Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

558 files changed, 441383 insertions, 0 deletions

diff --git a/kernel/.gitignore b/kernel/.gitignore
new file mode 100644
index 000000000..c6b299a6b
--- /dev/null
+++ b/kernel/.gitignore
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+/config_data
+/kheaders.md5
diff --git a/kernel/Kconfig.freezer b/kernel/Kconfig.freezer
new file mode 100644
index 000000000..68646feef
--- /dev/null
+++ b/kernel/Kconfig.freezer
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config FREEZER
+	def_bool PM_SLEEP || CGROUP_FREEZER
diff --git a/kernel/Kconfig.hz b/kernel/Kconfig.hz
new file mode 100644
index 000000000..38ef6d068
--- /dev/null
+++ b/kernel/Kconfig.hz
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Timer Interrupt Frequency Configuration
+#
+
+choice
+	prompt "Timer frequency"
+	default HZ_250
+	help
+	 Allows the configuration of the timer frequency. It is customary
+	 to have the timer interrupt run at 1000 Hz but 100 Hz may be more
+	 beneficial for servers and NUMA systems that do not need to have
+	 a fast response for user interaction and that may experience bus
+	 contention and cacheline bounces as a result of timer interrupts.
+	 Note that the timer interrupt occurs on each processor in an SMP
+	 environment leading to NR_CPUS * HZ number of timer interrupts
+	 per second.
+
+
+	config HZ_100
+		bool "100 HZ"
+	help
+	  100 Hz is a typical choice for servers, SMP and NUMA systems
+	  with lots of processors that may show reduced performance if
+	  too many timer interrupts are occurring.
+
+	config HZ_250
+		bool "250 HZ"
+	help
+	 250 Hz is a good compromise choice allowing server performance
+	 while also showing good interactive responsiveness even
+	 on SMP and NUMA systems. If you are going to be using NTSC video
+	 or multimedia, selected 300Hz instead.
+
+	config HZ_300
+		bool "300 HZ"
+	help
+	 300 Hz is a good compromise choice allowing server performance
+	 while also showing good interactive responsiveness even
+	 on SMP and NUMA systems and exactly dividing by both PAL and
+	 NTSC frame rates for video and multimedia work.
+
+	config HZ_1000
+		bool "1000 HZ"
+	help
+	 1000 Hz is the preferred choice for desktop systems and other
+	 systems requiring fast interactive responses to events.
+
+endchoice
+
+config HZ
+	int
+	default 100 if HZ_100
+	default 250 if HZ_250
+	default 300 if HZ_300
+	default 1000 if HZ_1000
+
+config SCHED_HRTICK
+	def_bool HIGH_RES_TIMERS
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
new file mode 100644
index 000000000..4198f0273
--- /dev/null
+++ b/kernel/Kconfig.locks
@@ -0,0 +1,261 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# The ARCH_INLINE foo is necessary because select ignores "depends on"
+#
+config ARCH_INLINE_SPIN_TRYLOCK
+	bool
+
+config ARCH_INLINE_SPIN_TRYLOCK_BH
+	bool
+
+config ARCH_INLINE_SPIN_LOCK
+	bool
+
+config ARCH_INLINE_SPIN_LOCK_BH
+	bool
+
+config ARCH_INLINE_SPIN_LOCK_IRQ
+	bool
+
+config ARCH_INLINE_SPIN_LOCK_IRQSAVE
+	bool
+
+config ARCH_INLINE_SPIN_UNLOCK
+	bool
+
+config ARCH_INLINE_SPIN_UNLOCK_BH
+	bool
+
+config ARCH_INLINE_SPIN_UNLOCK_IRQ
+	bool
+
+config ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
+	bool
+
+
+config ARCH_INLINE_READ_TRYLOCK
+	bool
+
+config ARCH_INLINE_READ_LOCK
+	bool
+
+config ARCH_INLINE_READ_LOCK_BH
+	bool
+
+config ARCH_INLINE_READ_LOCK_IRQ
+	bool
+
+config ARCH_INLINE_READ_LOCK_IRQSAVE
+	bool
+
+config ARCH_INLINE_READ_UNLOCK
+	bool
+
+config ARCH_INLINE_READ_UNLOCK_BH
+	bool
+
+config ARCH_INLINE_READ_UNLOCK_IRQ
+	bool
+
+config ARCH_INLINE_READ_UNLOCK_IRQRESTORE
+	bool
+
+
+config ARCH_INLINE_WRITE_TRYLOCK
+	bool
+
+config ARCH_INLINE_WRITE_LOCK
+	bool
+
+config ARCH_INLINE_WRITE_LOCK_BH
+	bool
+
+config ARCH_INLINE_WRITE_LOCK_IRQ
+	bool
+
+config ARCH_INLINE_WRITE_LOCK_IRQSAVE
+	bool
+
+config ARCH_INLINE_WRITE_UNLOCK
+	bool
+
+config ARCH_INLINE_WRITE_UNLOCK_BH
+	bool
+
+config ARCH_INLINE_WRITE_UNLOCK_IRQ
+	bool
+
+config ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
+	bool
+
+config UNINLINE_SPIN_UNLOCK
+	bool
+
+#
+# lock_* functions are inlined when:
+#   - DEBUG_SPINLOCK=n and GENERIC_LOCKBREAK=n and ARCH_INLINE_*LOCK=y
+#
+# trylock_* functions are inlined when:
+#   - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y
+#
+# unlock and unlock_irq functions are inlined when:
+#   - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y
+#  or
+#   - DEBUG_SPINLOCK=n and PREEMPTION=n
+#
+# unlock_bh and unlock_irqrestore functions are inlined when:
+#   - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y
+#
+
+if !DEBUG_SPINLOCK
+
+config INLINE_SPIN_TRYLOCK
+	def_bool y
+	depends on ARCH_INLINE_SPIN_TRYLOCK
+
+config INLINE_SPIN_TRYLOCK_BH
+	def_bool y
+	depends on ARCH_INLINE_SPIN_TRYLOCK_BH
+
+config INLINE_SPIN_LOCK
+	def_bool y
+	depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK
+
+config INLINE_SPIN_LOCK_BH
+	def_bool y
+	depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK_BH
+
+config INLINE_SPIN_LOCK_IRQ
+	def_bool y
+	depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK_IRQ
+
+config INLINE_SPIN_LOCK_IRQSAVE
+	def_bool y
+	depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK_IRQSAVE
+
+config INLINE_SPIN_UNLOCK_BH
+	def_bool y
+	depends on ARCH_INLINE_SPIN_UNLOCK_BH
+
+config INLINE_SPIN_UNLOCK_IRQ
+	def_bool y
+	depends on !PREEMPTION || ARCH_INLINE_SPIN_UNLOCK_IRQ
+
+config INLINE_SPIN_UNLOCK_IRQRESTORE
+	def_bool y
+	depends on ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
+
+
+config INLINE_READ_TRYLOCK
+	def_bool y
+	depends on ARCH_INLINE_READ_TRYLOCK
+
+config INLINE_READ_LOCK
+	def_bool y
+	depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK
+
+config INLINE_READ_LOCK_BH
+	def_bool y
+	depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK_BH
+
+config INLINE_READ_LOCK_IRQ
+	def_bool y
+	depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK_IRQ
+
+config INLINE_READ_LOCK_IRQSAVE
+	def_bool y
+	depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK_IRQSAVE
+
+config INLINE_READ_UNLOCK
+	def_bool y
+	depends on !PREEMPTION || ARCH_INLINE_READ_UNLOCK
+
+config INLINE_READ_UNLOCK_BH
+	def_bool y
+	depends on ARCH_INLINE_READ_UNLOCK_BH
+
+config INLINE_READ_UNLOCK_IRQ
+	def_bool y
+	depends on !PREEMPTION || ARCH_INLINE_READ_UNLOCK_IRQ
+
+config INLINE_READ_UNLOCK_IRQRESTORE
+	def_bool y
+	depends on ARCH_INLINE_READ_UNLOCK_IRQRESTORE
+
+
+config INLINE_WRITE_TRYLOCK
+	def_bool y
+	depends on ARCH_INLINE_WRITE_TRYLOCK
+
+config INLINE_WRITE_LOCK
+	def_bool y
+	depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK
+
+config INLINE_WRITE_LOCK_BH
+	def_bool y
+	depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK_BH
+
+config INLINE_WRITE_LOCK_IRQ
+	def_bool y
+	depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK_IRQ
+
+config INLINE_WRITE_LOCK_IRQSAVE
+	def_bool y
+	depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK_IRQSAVE
+
+config INLINE_WRITE_UNLOCK
+	def_bool y
+	depends on !PREEMPTION || ARCH_INLINE_WRITE_UNLOCK
+
+config INLINE_WRITE_UNLOCK_BH
+	def_bool y
+	depends on ARCH_INLINE_WRITE_UNLOCK_BH
+
+config INLINE_WRITE_UNLOCK_IRQ
+	def_bool y
+	depends on !PREEMPTION || ARCH_INLINE_WRITE_UNLOCK_IRQ
+
+config INLINE_WRITE_UNLOCK_IRQRESTORE
+	def_bool y
+	depends on ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
+
+endif
+
+config ARCH_SUPPORTS_ATOMIC_RMW
+	bool
+
+config MUTEX_SPIN_ON_OWNER
+	def_bool y
+	depends on SMP && ARCH_SUPPORTS_ATOMIC_RMW
+
+config RWSEM_SPIN_ON_OWNER
+       def_bool y
+       depends on SMP && ARCH_SUPPORTS_ATOMIC_RMW
+
+config LOCK_SPIN_ON_OWNER
+       def_bool y
+       depends on MUTEX_SPIN_ON_OWNER || RWSEM_SPIN_ON_OWNER
+
+config ARCH_USE_QUEUED_SPINLOCKS
+	bool
+
+config QUEUED_SPINLOCKS
+	def_bool y if ARCH_USE_QUEUED_SPINLOCKS
+	depends on SMP
+
+config BPF_ARCH_SPINLOCK
+	bool
+
+config ARCH_USE_QUEUED_RWLOCKS
+	bool
+
+config QUEUED_RWLOCKS
+	def_bool y if ARCH_USE_QUEUED_RWLOCKS
+	depends on SMP && !PREEMPT_RT
+
+config ARCH_HAS_MMIOWB
+	bool
+
+config MMIOWB
+	def_bool y if ARCH_HAS_MMIOWB
+	depends on SMP
diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
new file mode 100644
index 000000000..c2f1fd95a
--- /dev/null
+++ b/kernel/Kconfig.preempt
@@ -0,0 +1,136 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config PREEMPT_NONE_BUILD
+	bool
+
+config PREEMPT_VOLUNTARY_BUILD
+	bool
+
+config PREEMPT_BUILD
+	bool
+	select PREEMPTION
+	select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK
+
+choice
+	prompt "Preemption Model"
+	default PREEMPT_NONE
+
+config PREEMPT_NONE
+	bool "No Forced Preemption (Server)"
+	select PREEMPT_NONE_BUILD if !PREEMPT_DYNAMIC
+	help
+	  This is the traditional Linux preemption model, geared towards
+	  throughput. It will still provide good latencies most of the
+	  time, but there are no guarantees and occasional longer delays
+	  are possible.
+
+	  Select this option if you are building a kernel for a server or
+	  scientific/computation system, or if you want to maximize the
+	  raw processing power of the kernel, irrespective of scheduling
+	  latencies.
+
+config PREEMPT_VOLUNTARY
+	bool "Voluntary Kernel Preemption (Desktop)"
+	depends on !ARCH_NO_PREEMPT
+	select PREEMPT_VOLUNTARY_BUILD if !PREEMPT_DYNAMIC
+	help
+	  This option reduces the latency of the kernel by adding more
+	  "explicit preemption points" to the kernel code. These new
+	  preemption points have been selected to reduce the maximum
+	  latency of rescheduling, providing faster application reactions,
+	  at the cost of slightly lower throughput.
+
+	  This allows reaction to interactive events by allowing a
+	  low priority process to voluntarily preempt itself even if it
+	  is in kernel mode executing a system call. This allows
+	  applications to run more 'smoothly' even when the system is
+	  under load.
+
+	  Select this if you are building a kernel for a desktop system.
+
+config PREEMPT
+	bool "Preemptible Kernel (Low-Latency Desktop)"
+	depends on !ARCH_NO_PREEMPT
+	select PREEMPT_BUILD
+	help
+	  This option reduces the latency of the kernel by making
+	  all kernel code (that is not executing in a critical section)
+	  preemptible.  This allows reaction to interactive events by
+	  permitting a low priority process to be preempted involuntarily
+	  even if it is in kernel mode executing a system call and would
+	  otherwise not be about to reach a natural preemption point.
+	  This allows applications to run more 'smoothly' even when the
+	  system is under load, at the cost of slightly lower throughput
+	  and a slight runtime overhead to kernel code.
+
+	  Select this if you are building a kernel for a desktop or
+	  embedded system with latency requirements in the milliseconds
+	  range.
+
+config PREEMPT_RT
+	bool "Fully Preemptible Kernel (Real-Time)"
+	depends on EXPERT && ARCH_SUPPORTS_RT
+	select PREEMPTION
+	help
+	  This option turns the kernel into a real-time kernel by replacing
+	  various locking primitives (spinlocks, rwlocks, etc.) with
+	  preemptible priority-inheritance aware variants, enforcing
+	  interrupt threading and introducing mechanisms to break up long
+	  non-preemptible sections. This makes the kernel, except for very
+	  low level and critical code paths (entry code, scheduler, low
+	  level interrupt handling) fully preemptible and brings most
+	  execution contexts under scheduler control.
+
+	  Select this if you are building a kernel for systems which
+	  require real-time guarantees.
+
+endchoice
+
+config PREEMPT_COUNT
+       bool
+
+config PREEMPTION
+       bool
+       select PREEMPT_COUNT
+
+config PREEMPT_DYNAMIC
+	bool "Preemption behaviour defined on boot"
+	depends on HAVE_PREEMPT_DYNAMIC && !PREEMPT_RT
+	select JUMP_LABEL if HAVE_PREEMPT_DYNAMIC_KEY
+	select PREEMPT_BUILD
+	default y if HAVE_PREEMPT_DYNAMIC_CALL
+	help
+	  This option allows to define the preemption model on the kernel
+	  command line parameter and thus override the default preemption
+	  model defined during compile time.
+
+	  The feature is primarily interesting for Linux distributions which
+	  provide a pre-built kernel binary to reduce the number of kernel
+	  flavors they offer while still offering different usecases.
+
+	  The runtime overhead is negligible with HAVE_STATIC_CALL_INLINE enabled
+	  but if runtime patching is not available for the specific architecture
+	  then the potential overhead should be considered.
+
+	  Interesting if you want the same pre-built kernel should be used for
+	  both Server and Desktop workloads.
+
+config SCHED_CORE
+	bool "Core Scheduling for SMT"
+	depends on SCHED_SMT
+	help
+	  This option permits Core Scheduling, a means of coordinated task
+	  selection across SMT siblings. When enabled -- see
+	  prctl(PR_SCHED_CORE) -- task selection ensures that all SMT siblings
+	  will execute a task from the same 'core group', forcing idle when no
+	  matching task is found.
+
+	  Use of this feature includes:
+	   - mitigation of some (not all) SMT side channels;
+	   - limiting SMT interference to improve determinism and/or performance.
+
+	  SCHED_CORE is default disabled. When it is enabled and unused,
+	  which is the likely usage by Linux distributions, there should
+	  be no measurable impact on performance.
+
+
diff --git a/kernel/Makefile b/kernel/Makefile
new file mode 100644
index 000000000..ebc692242
--- /dev/null
+++ b/kernel/Makefile
@@ -0,0 +1,158 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the linux kernel.
+#
+
+obj-y     = fork.o exec_domain.o panic.o \
+	    cpu.o exit.o softirq.o resource.o \
+	    sysctl.o capability.o ptrace.o user.o \
+	    signal.o sys.o umh.o workqueue.o pid.o task_work.o \
+	    extable.o params.o \
+	    kthread.o sys_ni.o nsproxy.o \
+	    notifier.o ksysfs.o cred.o reboot.o \
+	    async.o range.o smpboot.o ucount.o regset.o
+
+obj-$(CONFIG_USERMODE_DRIVER) += usermode_driver.o
+obj-$(CONFIG_MODULES) += kmod.o
+obj-$(CONFIG_MULTIUSER) += groups.o
+
+ifdef CONFIG_FUNCTION_TRACER
+# Do not trace internal ftrace files
+CFLAGS_REMOVE_irq_work.o = $(CC_FLAGS_FTRACE)
+endif
+
+# Prevents flicker of uninteresting __do_softirq()/__local_bh_disable_ip()
+# in coverage traces.
+KCOV_INSTRUMENT_softirq.o := n
+# Avoid KCSAN instrumentation in softirq ("No shared variables, all the data
+# are CPU local" => assume no data races), to reduce overhead in interrupts.
+KCSAN_SANITIZE_softirq.o = n
+# These are called from save_stack_trace() on slub debug path,
+# and produce insane amounts of uninteresting coverage.
+KCOV_INSTRUMENT_extable.o := n
+KCOV_INSTRUMENT_stacktrace.o := n
+# Don't self-instrument.
+KCOV_INSTRUMENT_kcov.o := n
+# If sanitizers detect any issues in kcov, it may lead to recursion
+# via printk, etc.
+KASAN_SANITIZE_kcov.o := n
+KCSAN_SANITIZE_kcov.o := n
+UBSAN_SANITIZE_kcov.o := n
+KMSAN_SANITIZE_kcov.o := n
+CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack) -fno-stack-protector
+
+obj-y += sched/
+obj-y += locking/
+obj-y += power/
+obj-y += printk/
+obj-y += irq/
+obj-y += rcu/
+obj-y += livepatch/
+obj-y += dma/
+obj-y += entry/
+obj-$(CONFIG_MODULES) += module/
+
+obj-$(CONFIG_KCMP) += kcmp.o
+obj-$(CONFIG_FREEZER) += freezer.o
+obj-$(CONFIG_PROFILING) += profile.o
+obj-$(CONFIG_STACKTRACE) += stacktrace.o
+obj-y += time/
+obj-$(CONFIG_FUTEX) += futex/
+obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
+obj-$(CONFIG_SMP) += smp.o
+ifneq ($(CONFIG_SMP),y)
+obj-y += up.o
+endif
+obj-$(CONFIG_UID16) += uid16.o
+obj-$(CONFIG_MODULE_SIG_FORMAT) += module_signature.o
+obj-$(CONFIG_KALLSYMS) += kallsyms.o
+obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
+obj-$(CONFIG_CRASH_CORE) += crash_core.o
+obj-$(CONFIG_KEXEC_CORE) += kexec_core.o
+obj-$(CONFIG_KEXEC) += kexec.o
+obj-$(CONFIG_KEXEC_FILE) += kexec_file.o
+obj-$(CONFIG_KEXEC_ELF) += kexec_elf.o
+obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o
+obj-$(CONFIG_COMPAT) += compat.o
+obj-$(CONFIG_CGROUPS) += cgroup/
+obj-$(CONFIG_UTS_NS) += utsname.o
+obj-$(CONFIG_USER_NS) += user_namespace.o
+obj-$(CONFIG_PID_NS) += pid_namespace.o
+obj-$(CONFIG_IKCONFIG) += configs.o
+obj-$(CONFIG_IKHEADERS) += kheaders.o
+obj-$(CONFIG_SMP) += stop_machine.o
+obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
+obj-$(CONFIG_AUDITSYSCALL) += auditsc.o audit_watch.o audit_fsnotify.o audit_tree.o
+obj-$(CONFIG_GCOV_KERNEL) += gcov/
+obj-$(CONFIG_KCOV) += kcov.o
+obj-$(CONFIG_KPROBES) += kprobes.o
+obj-$(CONFIG_FAIL_FUNCTION) += fail_function.o
+obj-$(CONFIG_KGDB) += debug/
+obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
+obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
+obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_hld.o
+obj-$(CONFIG_SECCOMP) += seccomp.o
+obj-$(CONFIG_RELAY) += relay.o
+obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
+obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
+obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
+obj-$(CONFIG_TRACEPOINTS) += tracepoint.o
+obj-$(CONFIG_LATENCYTOP) += latencytop.o
+obj-$(CONFIG_FUNCTION_TRACER) += trace/
+obj-$(CONFIG_TRACING) += trace/
+obj-$(CONFIG_TRACE_CLOCK) += trace/
+obj-$(CONFIG_RING_BUFFER) += trace/
+obj-$(CONFIG_TRACEPOINTS) += trace/
+obj-$(CONFIG_RETHOOK) += trace/
+obj-$(CONFIG_IRQ_WORK) += irq_work.o
+obj-$(CONFIG_CPU_PM) += cpu_pm.o
+obj-$(CONFIG_BPF) += bpf/
+obj-$(CONFIG_KCSAN) += kcsan/
+obj-$(CONFIG_SHADOW_CALL_STACK) += scs.o
+obj-$(CONFIG_HAVE_STATIC_CALL) += static_call.o
+obj-$(CONFIG_HAVE_STATIC_CALL_INLINE) += static_call_inline.o
+obj-$(CONFIG_CFI_CLANG) += cfi.o
+
+obj-$(CONFIG_PERF_EVENTS) += events/
+
+obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o
+obj-$(CONFIG_PADATA) += padata.o
+obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
+obj-$(CONFIG_JUMP_LABEL) += jump_label.o
+obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o
+obj-$(CONFIG_TORTURE_TEST) += torture.o
+
+obj-$(CONFIG_HAS_IOMEM) += iomem.o
+obj-$(CONFIG_RSEQ) += rseq.o
+obj-$(CONFIG_WATCH_QUEUE) += watch_queue.o
+
+obj-$(CONFIG_RESOURCE_KUNIT_TEST) += resource_kunit.o
+obj-$(CONFIG_SYSCTL_KUNIT_TEST) += sysctl-test.o
+
+CFLAGS_stackleak.o += $(DISABLE_STACKLEAK_PLUGIN)
+obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o
+KASAN_SANITIZE_stackleak.o := n
+KCSAN_SANITIZE_stackleak.o := n
+KCOV_INSTRUMENT_stackleak.o := n
+
+obj-$(CONFIG_SCF_TORTURE_TEST) += scftorture.o
+
+$(obj)/configs.o: $(obj)/config_data.gz
+
+targets += config_data config_data.gz
+$(obj)/config_data.gz: $(obj)/config_data FORCE
+	$(call if_changed,gzip)
+
+filechk_cat = cat $<
+
+$(obj)/config_data: $(KCONFIG_CONFIG) FORCE
+	$(call filechk,cat)
+
+$(obj)/kheaders.o: $(obj)/kheaders_data.tar.xz
+
+quiet_cmd_genikh = CHK     $(obj)/kheaders_data.tar.xz
+      cmd_genikh = $(CONFIG_SHELL) $(srctree)/kernel/gen_kheaders.sh $@
+$(obj)/kheaders_data.tar.xz: FORCE
+	$(call cmd,genikh)
+
+clean-files := kheaders_data.tar.xz kheaders.md5
diff --git a/kernel/acct.c b/kernel/acct.c
new file mode 100644
index 000000000..034a26daa
--- /dev/null
+++ b/kernel/acct.c
@@ -0,0 +1,623 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/kernel/acct.c
+ *
+ *  BSD Process Accounting for Linux
+ *
+ *  Author: Marco van Wieringen <mvw@planets.elm.net>
+ *
+ *  Some code based on ideas and code from:
+ *  Thomas K. Dyas <tdyas@eden.rutgers.edu>
+ *
+ *  This file implements BSD-style process accounting. Whenever any
+ *  process exits, an accounting record of type "struct acct" is
+ *  written to the file specified with the acct() system call. It is
+ *  up to user-level programs to do useful things with the accounting
+ *  log. The kernel just provides the raw accounting information.
+ *
+ * (C) Copyright 1995 - 1997 Marco van Wieringen - ELM Consultancy B.V.
+ *
+ *  Plugged two leaks. 1) It didn't return acct_file into the free_filps if
+ *  the file happened to be read-only. 2) If the accounting was suspended
+ *  due to the lack of space it happily allowed to reopen it and completely
+ *  lost the old acct_file. 3/10/98, Al Viro.
+ *
+ *  Now we silently close acct_file on attempt to reopen. Cleaned sys_acct().
+ *  XTerms and EMACS are manifestations of pure evil. 21/10/98, AV.
+ *
+ *  Fixed a nasty interaction with sys_umount(). If the accounting
+ *  was suspeneded we failed to stop it on umount(). Messy.
+ *  Another one: remount to readonly didn't stop accounting.
+ *	Question: what should we do if we have CAP_SYS_ADMIN but not
+ *  CAP_SYS_PACCT? Current code does the following: umount returns -EBUSY
+ *  unless we are messing with the root. In that case we are getting a
+ *  real mess with do_remount_sb(). 9/11/98, AV.
+ *
+ *  Fixed a bunch of races (and pair of leaks). Probably not the best way,
+ *  but this one obviously doesn't introduce deadlocks. Later. BTW, found
+ *  one race (and leak) in BSD implementation.
+ *  OK, that's better. ANOTHER race and leak in BSD variant. There always
+ *  is one more bug... 10/11/98, AV.
+ *
+ *	Oh, fsck... Oopsable SMP race in do_process_acct() - we must hold
+ * ->mmap_lock to walk the vma list of current->mm. Nasty, since it leaks
+ * a struct file opened for write. Fixed. 2/6/2000, AV.
+ */
+
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/acct.h>
+#include <linux/capability.h>
+#include <linux/file.h>
+#include <linux/tty.h>
+#include <linux/security.h>
+#include <linux/vfs.h>
+#include <linux/jiffies.h>
+#include <linux/times.h>
+#include <linux/syscalls.h>
+#include <linux/mount.h>
+#include <linux/uaccess.h>
+#include <linux/sched/cputime.h>
+
+#include <asm/div64.h>
+#include <linux/pid_namespace.h>
+#include <linux/fs_pin.h>
+
+/*
+ * These constants control the amount of freespace that suspend and
+ * resume the process accounting system, and the time delay between
+ * each check.
+ * Turned into sysctl-controllable parameters. AV, 12/11/98
+ */
+
+static int acct_parm[3] = {4, 2, 30};
+#define RESUME		(acct_parm[0])	/* >foo% free space - resume */
+#define SUSPEND		(acct_parm[1])	/* <foo% free space - suspend */
+#define ACCT_TIMEOUT	(acct_parm[2])	/* foo second timeout between checks */
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table kern_acct_table[] = {
+	{
+		.procname       = "acct",
+		.data           = &acct_parm,
+		.maxlen         = 3*sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec,
+	},
+	{ }
+};
+
+static __init int kernel_acct_sysctls_init(void)
+{
+	register_sysctl_init("kernel", kern_acct_table);
+	return 0;
+}
+late_initcall(kernel_acct_sysctls_init);
+#endif /* CONFIG_SYSCTL */
+
+/*
+ * External references and all of the globals.
+ */
+
+struct bsd_acct_struct {
+	struct fs_pin		pin;
+	atomic_long_t		count;
+	struct rcu_head		rcu;
+	struct mutex		lock;
+	int			active;
+	unsigned long		needcheck;
+	struct file		*file;
+	struct pid_namespace	*ns;
+	struct work_struct	work;
+	struct completion	done;
+};
+
+static void do_acct_process(struct bsd_acct_struct *acct);
+
+/*
+ * Check the amount of free space and suspend/resume accordingly.
+ */
+static int check_free_space(struct bsd_acct_struct *acct)
+{
+	struct kstatfs sbuf;
+
+	if (time_is_after_jiffies(acct->needcheck))
+		goto out;
+
+	/* May block */
+	if (vfs_statfs(&acct->file->f_path, &sbuf))
+		goto out;
+
+	if (acct->active) {
+		u64 suspend = sbuf.f_blocks * SUSPEND;
+		do_div(suspend, 100);
+		if (sbuf.f_bavail <= suspend) {
+			acct->active = 0;
+			pr_info("Process accounting paused\n");
+		}
+	} else {
+		u64 resume = sbuf.f_blocks * RESUME;
+		do_div(resume, 100);
+		if (sbuf.f_bavail >= resume) {
+			acct->active = 1;
+			pr_info("Process accounting resumed\n");
+		}
+	}
+
+	acct->needcheck = jiffies + ACCT_TIMEOUT*HZ;
+out:
+	return acct->active;
+}
+
+static void acct_put(struct bsd_acct_struct *p)
+{
+	if (atomic_long_dec_and_test(&p->count))
+		kfree_rcu(p, rcu);
+}
+
+static inline struct bsd_acct_struct *to_acct(struct fs_pin *p)
+{
+	return p ? container_of(p, struct bsd_acct_struct, pin) : NULL;
+}
+
+static struct bsd_acct_struct *acct_get(struct pid_namespace *ns)
+{
+	struct bsd_acct_struct *res;
+again:
+	smp_rmb();
+	rcu_read_lock();
+	res = to_acct(READ_ONCE(ns->bacct));
+	if (!res) {
+		rcu_read_unlock();
+		return NULL;
+	}
+	if (!atomic_long_inc_not_zero(&res->count)) {
+		rcu_read_unlock();
+		cpu_relax();
+		goto again;
+	}
+	rcu_read_unlock();
+	mutex_lock(&res->lock);
+	if (res != to_acct(READ_ONCE(ns->bacct))) {
+		mutex_unlock(&res->lock);
+		acct_put(res);
+		goto again;
+	}
+	return res;
+}
+
+static void acct_pin_kill(struct fs_pin *pin)
+{
+	struct bsd_acct_struct *acct = to_acct(pin);
+	mutex_lock(&acct->lock);
+	do_acct_process(acct);
+	schedule_work(&acct->work);
+	wait_for_completion(&acct->done);
+	cmpxchg(&acct->ns->bacct, pin, NULL);
+	mutex_unlock(&acct->lock);
+	pin_remove(pin);
+	acct_put(acct);
+}
+
+static void close_work(struct work_struct *work)
+{
+	struct bsd_acct_struct *acct = container_of(work, struct bsd_acct_struct, work);
+	struct file *file = acct->file;
+	if (file->f_op->flush)
+		file->f_op->flush(file, NULL);
+	__fput_sync(file);
+	complete(&acct->done);
+}
+
+static int acct_on(struct filename *pathname)
+{
+	struct file *file;
+	struct vfsmount *mnt, *internal;
+	struct pid_namespace *ns = task_active_pid_ns(current);
+	struct bsd_acct_struct *acct;
+	struct fs_pin *old;
+	int err;
+
+	acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL);
+	if (!acct)
+		return -ENOMEM;
+
+	/* Difference from BSD - they don't do O_APPEND */
+	file = file_open_name(pathname, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
+	if (IS_ERR(file)) {
+		kfree(acct);
+		return PTR_ERR(file);
+	}
+
+	if (!S_ISREG(file_inode(file)->i_mode)) {
+		kfree(acct);
+		filp_close(file, NULL);
+		return -EACCES;
+	}
+
+	if (!(file->f_mode & FMODE_CAN_WRITE)) {
+		kfree(acct);
+		filp_close(file, NULL);
+		return -EIO;
+	}
+	internal = mnt_clone_internal(&file->f_path);
+	if (IS_ERR(internal)) {
+		kfree(acct);
+		filp_close(file, NULL);
+		return PTR_ERR(internal);
+	}
+	err = __mnt_want_write(internal);
+	if (err) {
+		mntput(internal);
+		kfree(acct);
+		filp_close(file, NULL);
+		return err;
+	}
+	mnt = file->f_path.mnt;
+	file->f_path.mnt = internal;
+
+	atomic_long_set(&acct->count, 1);
+	init_fs_pin(&acct->pin, acct_pin_kill);
+	acct->file = file;
+	acct->needcheck = jiffies;
+	acct->ns = ns;
+	mutex_init(&acct->lock);
+	INIT_WORK(&acct->work, close_work);
+	init_completion(&acct->done);
+	mutex_lock_nested(&acct->lock, 1);	/* nobody has seen it yet */
+	pin_insert(&acct->pin, mnt);
+
+	rcu_read_lock();
+	old = xchg(&ns->bacct, &acct->pin);
+	mutex_unlock(&acct->lock);
+	pin_kill(old);
+	__mnt_drop_write(mnt);
+	mntput(mnt);
+	return 0;
+}
+
+static DEFINE_MUTEX(acct_on_mutex);
+
+/**
+ * sys_acct - enable/disable process accounting
+ * @name: file name for accounting records or NULL to shutdown accounting
+ *
+ * sys_acct() is the only system call needed to implement process
+ * accounting. It takes the name of the file where accounting records
+ * should be written. If the filename is NULL, accounting will be
+ * shutdown.
+ *
+ * Returns: 0 for success or negative errno values for failure.
+ */
+SYSCALL_DEFINE1(acct, const char __user *, name)
+{
+	int error = 0;
+
+	if (!capable(CAP_SYS_PACCT))
+		return -EPERM;
+
+	if (name) {
+		struct filename *tmp = getname(name);
+
+		if (IS_ERR(tmp))
+			return PTR_ERR(tmp);
+		mutex_lock(&acct_on_mutex);
+		error = acct_on(tmp);
+		mutex_unlock(&acct_on_mutex);
+		putname(tmp);
+	} else {
+		rcu_read_lock();
+		pin_kill(task_active_pid_ns(current)->bacct);
+	}
+
+	return error;
+}
+
+void acct_exit_ns(struct pid_namespace *ns)
+{
+	rcu_read_lock();
+	pin_kill(ns->bacct);
+}
+
+/*
+ *  encode an unsigned long into a comp_t
+ *
+ *  This routine has been adopted from the encode_comp_t() function in
+ *  the kern_acct.c file of the FreeBSD operating system. The encoding
+ *  is a 13-bit fraction with a 3-bit (base 8) exponent.
+ */
+
+#define	MANTSIZE	13			/* 13 bit mantissa. */
+#define	EXPSIZE		3			/* Base 8 (3 bit) exponent. */
+#define	MAXFRACT	((1 << MANTSIZE) - 1)	/* Maximum fractional value. */
+
+static comp_t encode_comp_t(unsigned long value)
+{
+	int exp, rnd;
+
+	exp = rnd = 0;
+	while (value > MAXFRACT) {
+		rnd = value & (1 << (EXPSIZE - 1));	/* Round up? */
+		value >>= EXPSIZE;	/* Base 8 exponent == 3 bit shift. */
+		exp++;
+	}
+
+	/*
+	 * If we need to round up, do it (and handle overflow correctly).
+	 */
+	if (rnd && (++value > MAXFRACT)) {
+		value >>= EXPSIZE;
+		exp++;
+	}
+
+	if (exp > (((comp_t) ~0U) >> MANTSIZE))
+		return (comp_t) ~0U;
+	/*
+	 * Clean it up and polish it off.
+	 */
+	exp <<= MANTSIZE;		/* Shift the exponent into place */
+	exp += value;			/* and add on the mantissa. */
+	return exp;
+}
+
+#if ACCT_VERSION == 1 || ACCT_VERSION == 2
+/*
+ * encode an u64 into a comp2_t (24 bits)
+ *
+ * Format: 5 bit base 2 exponent, 20 bits mantissa.
+ * The leading bit of the mantissa is not stored, but implied for
+ * non-zero exponents.
+ * Largest encodable value is 50 bits.
+ */
+
+#define MANTSIZE2       20                      /* 20 bit mantissa. */
+#define EXPSIZE2        5                       /* 5 bit base 2 exponent. */
+#define MAXFRACT2       ((1ul << MANTSIZE2) - 1) /* Maximum fractional value. */
+#define MAXEXP2         ((1 << EXPSIZE2) - 1)    /* Maximum exponent. */
+
+static comp2_t encode_comp2_t(u64 value)
+{
+	int exp, rnd;
+
+	exp = (value > (MAXFRACT2>>1));
+	rnd = 0;
+	while (value > MAXFRACT2) {
+		rnd = value & 1;
+		value >>= 1;
+		exp++;
+	}
+
+	/*
+	 * If we need to round up, do it (and handle overflow correctly).
+	 */
+	if (rnd && (++value > MAXFRACT2)) {
+		value >>= 1;
+		exp++;
+	}
+
+	if (exp > MAXEXP2) {
+		/* Overflow. Return largest representable number instead. */
+		return (1ul << (MANTSIZE2+EXPSIZE2-1)) - 1;
+	} else {
+		return (value & (MAXFRACT2>>1)) | (exp << (MANTSIZE2-1));
+	}
+}
+#elif ACCT_VERSION == 3
+/*
+ * encode an u64 into a 32 bit IEEE float
+ */
+static u32 encode_float(u64 value)
+{
+	unsigned exp = 190;
+	unsigned u;
+
+	if (value == 0)
+		return 0;
+	while ((s64)value > 0) {
+		value <<= 1;
+		exp--;
+	}
+	u = (u32)(value >> 40) & 0x7fffffu;
+	return u | (exp << 23);
+}
+#endif
+
+/*
+ *  Write an accounting entry for an exiting process
+ *
+ *  The acct_process() call is the workhorse of the process
+ *  accounting system. The struct acct is built here and then written
+ *  into the accounting file. This function should only be called from
+ *  do_exit() or when switching to a different output file.
+ */
+
+static void fill_ac(acct_t *ac)
+{
+	struct pacct_struct *pacct = &current->signal->pacct;
+	u64 elapsed, run_time;
+	time64_t btime;
+	struct tty_struct *tty;
+
+	/*
+	 * Fill the accounting struct with the needed info as recorded
+	 * by the different kernel functions.
+	 */
+	memset(ac, 0, sizeof(acct_t));
+
+	ac->ac_version = ACCT_VERSION | ACCT_BYTEORDER;
+	strlcpy(ac->ac_comm, current->comm, sizeof(ac->ac_comm));
+
+	/* calculate run_time in nsec*/
+	run_time = ktime_get_ns();
+	run_time -= current->group_leader->start_time;
+	/* convert nsec -> AHZ */
+	elapsed = nsec_to_AHZ(run_time);
+#if ACCT_VERSION == 3
+	ac->ac_etime = encode_float(elapsed);
+#else
+	ac->ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ?
+				(unsigned long) elapsed : (unsigned long) -1l);
+#endif
+#if ACCT_VERSION == 1 || ACCT_VERSION == 2
+	{
+		/* new enlarged etime field */
+		comp2_t etime = encode_comp2_t(elapsed);
+
+		ac->ac_etime_hi = etime >> 16;
+		ac->ac_etime_lo = (u16) etime;
+	}
+#endif
+	do_div(elapsed, AHZ);
+	btime = ktime_get_real_seconds() - elapsed;
+	ac->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX);
+#if ACCT_VERSION==2
+	ac->ac_ahz = AHZ;
+#endif
+
+	spin_lock_irq(&current->sighand->siglock);
+	tty = current->signal->tty;	/* Safe as we hold the siglock */
+	ac->ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
+	ac->ac_utime = encode_comp_t(nsec_to_AHZ(pacct->ac_utime));
+	ac->ac_stime = encode_comp_t(nsec_to_AHZ(pacct->ac_stime));
+	ac->ac_flag = pacct->ac_flag;
+	ac->ac_mem = encode_comp_t(pacct->ac_mem);
+	ac->ac_minflt = encode_comp_t(pacct->ac_minflt);
+	ac->ac_majflt = encode_comp_t(pacct->ac_majflt);
+	ac->ac_exitcode = pacct->ac_exitcode;
+	spin_unlock_irq(&current->sighand->siglock);
+}
+/*
+ *  do_acct_process does all actual work. Caller holds the reference to file.
+ */
+static void do_acct_process(struct bsd_acct_struct *acct)
+{
+	acct_t ac;
+	unsigned long flim;
+	const struct cred *orig_cred;
+	struct file *file = acct->file;
+
+	/*
+	 * Accounting records are not subject to resource limits.
+	 */
+	flim = rlimit(RLIMIT_FSIZE);
+	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
+	/* Perform file operations on behalf of whoever enabled accounting */
+	orig_cred = override_creds(file->f_cred);
+
+	/*
+	 * First check to see if there is enough free_space to continue
+	 * the process accounting system.
+	 */
+	if (!check_free_space(acct))
+		goto out;
+
+	fill_ac(&ac);
+	/* we really need to bite the bullet and change layout */
+	ac.ac_uid = from_kuid_munged(file->f_cred->user_ns, orig_cred->uid);
+	ac.ac_gid = from_kgid_munged(file->f_cred->user_ns, orig_cred->gid);
+#if ACCT_VERSION == 1 || ACCT_VERSION == 2
+	/* backward-compatible 16 bit fields */
+	ac.ac_uid16 = ac.ac_uid;
+	ac.ac_gid16 = ac.ac_gid;
+#elif ACCT_VERSION == 3
+	{
+		struct pid_namespace *ns = acct->ns;
+
+		ac.ac_pid = task_tgid_nr_ns(current, ns);
+		rcu_read_lock();
+		ac.ac_ppid = task_tgid_nr_ns(rcu_dereference(current->real_parent),
+					     ns);
+		rcu_read_unlock();
+	}
+#endif
+	/*
+	 * Get freeze protection. If the fs is frozen, just skip the write
+	 * as we could deadlock the system otherwise.
+	 */
+	if (file_start_write_trylock(file)) {
+		/* it's been opened O_APPEND, so position is irrelevant */
+		loff_t pos = 0;
+		__kernel_write(file, &ac, sizeof(acct_t), &pos);
+		file_end_write(file);
+	}
+out:
+	current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
+	revert_creds(orig_cred);
+}
+
+/**
+ * acct_collect - collect accounting information into pacct_struct
+ * @exitcode: task exit code
+ * @group_dead: not 0, if this thread is the last one in the process.
+ */
+void acct_collect(long exitcode, int group_dead)
+{
+	struct pacct_struct *pacct = &current->signal->pacct;
+	u64 utime, stime;
+	unsigned long vsize = 0;
+
+	if (group_dead && current->mm) {
+		struct mm_struct *mm = current->mm;
+		VMA_ITERATOR(vmi, mm, 0);
+		struct vm_area_struct *vma;
+
+		mmap_read_lock(mm);
+		for_each_vma(vmi, vma)
+			vsize += vma->vm_end - vma->vm_start;
+		mmap_read_unlock(mm);
+	}
+
+	spin_lock_irq(&current->sighand->siglock);
+	if (group_dead)
+		pacct->ac_mem = vsize / 1024;
+	if (thread_group_leader(current)) {
+		pacct->ac_exitcode = exitcode;
+		if (current->flags & PF_FORKNOEXEC)
+			pacct->ac_flag |= AFORK;
+	}
+	if (current->flags & PF_SUPERPRIV)
+		pacct->ac_flag |= ASU;
+	if (current->flags & PF_DUMPCORE)
+		pacct->ac_flag |= ACORE;
+	if (current->flags & PF_SIGNALED)
+		pacct->ac_flag |= AXSIG;
+
+	task_cputime(current, &utime, &stime);
+	pacct->ac_utime += utime;
+	pacct->ac_stime += stime;
+	pacct->ac_minflt += current->min_flt;
+	pacct->ac_majflt += current->maj_flt;
+	spin_unlock_irq(&current->sighand->siglock);
+}
+
+static void slow_acct_process(struct pid_namespace *ns)
+{
+	for ( ; ns; ns = ns->parent) {
+		struct bsd_acct_struct *acct = acct_get(ns);
+		if (acct) {
+			do_acct_process(acct);
+			mutex_unlock(&acct->lock);
+			acct_put(acct);
+		}
+	}
+}
+
+/**
+ * acct_process - handles process accounting for an exiting task
+ */
+void acct_process(void)
+{
+	struct pid_namespace *ns;
+
+	/*
+	 * This loop is safe lockless, since current is still
+	 * alive and holds its namespace, which in turn holds
+	 * its parent.
+	 */
+	for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent) {
+		if (ns->bacct)
+			break;
+	}
+	if (unlikely(ns))
+		slow_acct_process(ns);
+}
diff --git a/kernel/async.c b/kernel/async.c
new file mode 100644
index 000000000..673bba6bd
--- /dev/null
+++ b/kernel/async.c
@@ -0,0 +1,346 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * async.c: Asynchronous function calls for boot performance
+ *
+ * (C) Copyright 2009 Intel Corporation
+ * Author: Arjan van de Ven <arjan@linux.intel.com>
+ */
+
+
+/*
+
+Goals and Theory of Operation
+
+The primary goal of this feature is to reduce the kernel boot time,
+by doing various independent hardware delays and discovery operations
+decoupled and not strictly serialized.
+
+More specifically, the asynchronous function call concept allows
+certain operations (primarily during system boot) to happen
+asynchronously, out of order, while these operations still
+have their externally visible parts happen sequentially and in-order.
+(not unlike how out-of-order CPUs retire their instructions in order)
+
+Key to the asynchronous function call implementation is the concept of
+a "sequence cookie" (which, although it has an abstracted type, can be
+thought of as a monotonically incrementing number).
+
+The async core will assign each scheduled event such a sequence cookie and
+pass this to the called functions.
+
+The asynchronously called function should before doing a globally visible
+operation, such as registering device numbers, call the
+async_synchronize_cookie() function and pass in its own cookie. The
+async_synchronize_cookie() function will make sure that all asynchronous
+operations that were scheduled prior to the operation corresponding with the
+cookie have completed.
+
+Subsystem/driver initialization code that scheduled asynchronous probe
+functions, but which shares global resources with other drivers/subsystems
+that do not use the asynchronous call feature, need to do a full
+synchronization with the async_synchronize_full() function, before returning
+from their init function. This is to maintain strict ordering between the
+asynchronous and synchronous parts of the kernel.
+
+*/
+
+#include <linux/async.h>
+#include <linux/atomic.h>
+#include <linux/ktime.h>
+#include <linux/export.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#include "workqueue_internal.h"
+
+static async_cookie_t next_cookie = 1;
+
+#define MAX_WORK		32768
+#define ASYNC_COOKIE_MAX	ULLONG_MAX	/* infinity cookie */
+
+static LIST_HEAD(async_global_pending);	/* pending from all registered doms */
+static ASYNC_DOMAIN(async_dfl_domain);
+static DEFINE_SPINLOCK(async_lock);
+
+struct async_entry {
+	struct list_head	domain_list;
+	struct list_head	global_list;
+	struct work_struct	work;
+	async_cookie_t		cookie;
+	async_func_t		func;
+	void			*data;
+	struct async_domain	*domain;
+};
+
+static DECLARE_WAIT_QUEUE_HEAD(async_done);
+
+static atomic_t entry_count;
+
+static long long microseconds_since(ktime_t start)
+{
+	ktime_t now = ktime_get();
+	return ktime_to_ns(ktime_sub(now, start)) >> 10;
+}
+
+static async_cookie_t lowest_in_progress(struct async_domain *domain)
+{
+	struct async_entry *first = NULL;
+	async_cookie_t ret = ASYNC_COOKIE_MAX;
+	unsigned long flags;
+
+	spin_lock_irqsave(&async_lock, flags);
+
+	if (domain) {
+		if (!list_empty(&domain->pending))
+			first = list_first_entry(&domain->pending,
+					struct async_entry, domain_list);
+	} else {
+		if (!list_empty(&async_global_pending))
+			first = list_first_entry(&async_global_pending,
+					struct async_entry, global_list);
+	}
+
+	if (first)
+		ret = first->cookie;
+
+	spin_unlock_irqrestore(&async_lock, flags);
+	return ret;
+}
+
+/*
+ * pick the first pending entry and run it
+ */
+static void async_run_entry_fn(struct work_struct *work)
+{
+	struct async_entry *entry =
+		container_of(work, struct async_entry, work);
+	unsigned long flags;
+	ktime_t calltime;
+
+	/* 1) run (and print duration) */
+	pr_debug("calling  %lli_%pS @ %i\n", (long long)entry->cookie,
+		 entry->func, task_pid_nr(current));
+	calltime = ktime_get();
+
+	entry->func(entry->data, entry->cookie);
+
+	pr_debug("initcall %lli_%pS returned after %lld usecs\n",
+		 (long long)entry->cookie, entry->func,
+		 microseconds_since(calltime));
+
+	/* 2) remove self from the pending queues */
+	spin_lock_irqsave(&async_lock, flags);
+	list_del_init(&entry->domain_list);
+	list_del_init(&entry->global_list);
+
+	/* 3) free the entry */
+	kfree(entry);
+	atomic_dec(&entry_count);
+
+	spin_unlock_irqrestore(&async_lock, flags);
+
+	/* 4) wake up any waiters */
+	wake_up(&async_done);
+}
+
+static async_cookie_t __async_schedule_node_domain(async_func_t func,
+						   void *data, int node,
+						   struct async_domain *domain,
+						   struct async_entry *entry)
+{
+	async_cookie_t newcookie;
+	unsigned long flags;
+
+	INIT_LIST_HEAD(&entry->domain_list);
+	INIT_LIST_HEAD(&entry->global_list);
+	INIT_WORK(&entry->work, async_run_entry_fn);
+	entry->func = func;
+	entry->data = data;
+	entry->domain = domain;
+
+	spin_lock_irqsave(&async_lock, flags);
+
+	/* allocate cookie and queue */
+	newcookie = entry->cookie = next_cookie++;
+
+	list_add_tail(&entry->domain_list, &domain->pending);
+	if (domain->registered)
+		list_add_tail(&entry->global_list, &async_global_pending);
+
+	atomic_inc(&entry_count);
+	spin_unlock_irqrestore(&async_lock, flags);
+
+	/* schedule for execution */
+	queue_work_node(node, system_unbound_wq, &entry->work);
+
+	return newcookie;
+}
+
+/**
+ * async_schedule_node_domain - NUMA specific version of async_schedule_domain
+ * @func: function to execute asynchronously
+ * @data: data pointer to pass to the function
+ * @node: NUMA node that we want to schedule this on or close to
+ * @domain: the domain
+ *
+ * Returns an async_cookie_t that may be used for checkpointing later.
+ * @domain may be used in the async_synchronize_*_domain() functions to
+ * wait within a certain synchronization domain rather than globally.
+ *
+ * Note: This function may be called from atomic or non-atomic contexts.
+ *
+ * The node requested will be honored on a best effort basis. If the node
+ * has no CPUs associated with it then the work is distributed among all
+ * available CPUs.
+ */
+async_cookie_t async_schedule_node_domain(async_func_t func, void *data,
+					  int node, struct async_domain *domain)
+{
+	struct async_entry *entry;
+	unsigned long flags;
+	async_cookie_t newcookie;
+
+	/* allow irq-off callers */
+	entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC);
+
+	/*
+	 * If we're out of memory or if there's too much work
+	 * pending already, we execute synchronously.
+	 */
+	if (!entry || atomic_read(&entry_count) > MAX_WORK) {
+		kfree(entry);
+		spin_lock_irqsave(&async_lock, flags);
+		newcookie = next_cookie++;
+		spin_unlock_irqrestore(&async_lock, flags);
+
+		/* low on memory.. run synchronously */
+		func(data, newcookie);
+		return newcookie;
+	}
+
+	return __async_schedule_node_domain(func, data, node, domain, entry);
+}
+EXPORT_SYMBOL_GPL(async_schedule_node_domain);
+
+/**
+ * async_schedule_node - NUMA specific version of async_schedule
+ * @func: function to execute asynchronously
+ * @data: data pointer to pass to the function
+ * @node: NUMA node that we want to schedule this on or close to
+ *
+ * Returns an async_cookie_t that may be used for checkpointing later.
+ * Note: This function may be called from atomic or non-atomic contexts.
+ *
+ * The node requested will be honored on a best effort basis. If the node
+ * has no CPUs associated with it then the work is distributed among all
+ * available CPUs.
+ */
+async_cookie_t async_schedule_node(async_func_t func, void *data, int node)
+{
+	return async_schedule_node_domain(func, data, node, &async_dfl_domain);
+}
+EXPORT_SYMBOL_GPL(async_schedule_node);
+
+/**
+ * async_schedule_dev_nocall - A simplified variant of async_schedule_dev()
+ * @func: function to execute asynchronously
+ * @dev: device argument to be passed to function
+ *
+ * @dev is used as both the argument for the function and to provide NUMA
+ * context for where to run the function.
+ *
+ * If the asynchronous execution of @func is scheduled successfully, return
+ * true. Otherwise, do nothing and return false, unlike async_schedule_dev()
+ * that will run the function synchronously then.
+ */
+bool async_schedule_dev_nocall(async_func_t func, struct device *dev)
+{
+	struct async_entry *entry;
+
+	entry = kzalloc(sizeof(struct async_entry), GFP_KERNEL);
+
+	/* Give up if there is no memory or too much work. */
+	if (!entry || atomic_read(&entry_count) > MAX_WORK) {
+		kfree(entry);
+		return false;
+	}
+
+	__async_schedule_node_domain(func, dev, dev_to_node(dev),
+				     &async_dfl_domain, entry);
+	return true;
+}
+
+/**
+ * async_synchronize_full - synchronize all asynchronous function calls
+ *
+ * This function waits until all asynchronous function calls have been done.
+ */
+void async_synchronize_full(void)
+{
+	async_synchronize_full_domain(NULL);
+}
+EXPORT_SYMBOL_GPL(async_synchronize_full);
+
+/**
+ * async_synchronize_full_domain - synchronize all asynchronous function within a certain domain
+ * @domain: the domain to synchronize
+ *
+ * This function waits until all asynchronous function calls for the
+ * synchronization domain specified by @domain have been done.
+ */
+void async_synchronize_full_domain(struct async_domain *domain)
+{
+	async_synchronize_cookie_domain(ASYNC_COOKIE_MAX, domain);
+}
+EXPORT_SYMBOL_GPL(async_synchronize_full_domain);
+
+/**
+ * async_synchronize_cookie_domain - synchronize asynchronous function calls within a certain domain with cookie checkpointing
+ * @cookie: async_cookie_t to use as checkpoint
+ * @domain: the domain to synchronize (%NULL for all registered domains)
+ *
+ * This function waits until all asynchronous function calls for the
+ * synchronization domain specified by @domain submitted prior to @cookie
+ * have been done.
+ */
+void async_synchronize_cookie_domain(async_cookie_t cookie, struct async_domain *domain)
+{
+	ktime_t starttime;
+
+	pr_debug("async_waiting @ %i\n", task_pid_nr(current));
+	starttime = ktime_get();
+
+	wait_event(async_done, lowest_in_progress(domain) >= cookie);
+
+	pr_debug("async_continuing @ %i after %lli usec\n", task_pid_nr(current),
+		 microseconds_since(starttime));
+}
+EXPORT_SYMBOL_GPL(async_synchronize_cookie_domain);
+
+/**
+ * async_synchronize_cookie - synchronize asynchronous function calls with cookie checkpointing
+ * @cookie: async_cookie_t to use as checkpoint
+ *
+ * This function waits until all asynchronous function calls prior to @cookie
+ * have been done.
+ */
+void async_synchronize_cookie(async_cookie_t cookie)
+{
+	async_synchronize_cookie_domain(cookie, &async_dfl_domain);
+}
+EXPORT_SYMBOL_GPL(async_synchronize_cookie);
+
+/**
+ * current_is_async - is %current an async worker task?
+ *
+ * Returns %true if %current is an async worker task.
+ */
+bool current_is_async(void)
+{
+	struct worker *worker = current_wq_worker();
+
+	return worker && worker->current_func == async_run_entry_fn;
+}
+EXPORT_SYMBOL_GPL(current_is_async);
diff --git a/kernel/audit.c b/kernel/audit.c
new file mode 100644
index 000000000..9bc0b0301
--- /dev/null
+++ b/kernel/audit.c
@@ -0,0 +1,2464 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* audit.c -- Auditing support
+ * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
+ * System-call specific features have moved to auditsc.c
+ *
+ * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
+ * All Rights Reserved.
+ *
+ * Written by Rickard E. (Rik) Faith <faith@redhat.com>
+ *
+ * Goals: 1) Integrate fully with Security Modules.
+ *	  2) Minimal run-time overhead:
+ *	     a) Minimal when syscall auditing is disabled (audit_enable=0).
+ *	     b) Small when syscall auditing is enabled and no audit record
+ *		is generated (defer as much work as possible to record
+ *		generation time):
+ *		i) context is allocated,
+ *		ii) names from getname are stored without a copy, and
+ *		iii) inode information stored from path_lookup.
+ *	  3) Ability to disable syscall auditing at boot time (audit=0).
+ *	  4) Usable by other parts of the kernel (if audit_log* is called,
+ *	     then a syscall record will be generated automatically for the
+ *	     current syscall).
+ *	  5) Netlink interface to user-space.
+ *	  6) Support low-overhead kernel-based filtering to minimize the
+ *	     information that must be passed to user-space.
+ *
+ * Audit userspace, documentation, tests, and bug/issue trackers:
+ * 	https://github.com/linux-audit
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/file.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/atomic.h>
+#include <linux/mm.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/kthread.h>
+#include <linux/kernel.h>
+#include <linux/syscalls.h>
+#include <linux/spinlock.h>
+#include <linux/rcupdate.h>
+#include <linux/mutex.h>
+#include <linux/gfp.h>
+#include <linux/pid.h>
+
+#include <linux/audit.h>
+
+#include <net/sock.h>
+#include <net/netlink.h>
+#include <linux/skbuff.h>
+#ifdef CONFIG_SECURITY
+#include <linux/security.h>
+#endif
+#include <linux/freezer.h>
+#include <linux/pid_namespace.h>
+#include <net/netns/generic.h>
+
+#include "audit.h"
+
+/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
+ * (Initialization happens after skb_init is called.) */
+#define AUDIT_DISABLED		-1
+#define AUDIT_UNINITIALIZED	0
+#define AUDIT_INITIALIZED	1
+static int	audit_initialized = AUDIT_UNINITIALIZED;
+
+u32		audit_enabled = AUDIT_OFF;
+bool		audit_ever_enabled = !!AUDIT_OFF;
+
+EXPORT_SYMBOL_GPL(audit_enabled);
+
+/* Default state when kernel boots without any parameters. */
+static u32	audit_default = AUDIT_OFF;
+
+/* If auditing cannot proceed, audit_failure selects what happens. */
+static u32	audit_failure = AUDIT_FAIL_PRINTK;
+
+/* private audit network namespace index */
+static unsigned int audit_net_id;
+
+/**
+ * struct audit_net - audit private network namespace data
+ * @sk: communication socket
+ */
+struct audit_net {
+	struct sock *sk;
+};
+
+/**
+ * struct auditd_connection - kernel/auditd connection state
+ * @pid: auditd PID
+ * @portid: netlink portid
+ * @net: the associated network namespace
+ * @rcu: RCU head
+ *
+ * Description:
+ * This struct is RCU protected; you must either hold the RCU lock for reading
+ * or the associated spinlock for writing.
+ */
+struct auditd_connection {
+	struct pid *pid;
+	u32 portid;
+	struct net *net;
+	struct rcu_head rcu;
+};
+static struct auditd_connection __rcu *auditd_conn;
+static DEFINE_SPINLOCK(auditd_conn_lock);
+
+/* If audit_rate_limit is non-zero, limit the rate of sending audit records
+ * to that number per second.  This prevents DoS attacks, but results in
+ * audit records being dropped. */
+static u32	audit_rate_limit;
+
+/* Number of outstanding audit_buffers allowed.
+ * When set to zero, this means unlimited. */
+static u32	audit_backlog_limit = 64;
+#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
+static u32	audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
+
+/* The identity of the user shutting down the audit system. */
+static kuid_t		audit_sig_uid = INVALID_UID;
+static pid_t		audit_sig_pid = -1;
+static u32		audit_sig_sid;
+
+/* Records can be lost in several ways:
+   0) [suppressed in audit_alloc]
+   1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
+   2) out of memory in audit_log_move [alloc_skb]
+   3) suppressed due to audit_rate_limit
+   4) suppressed due to audit_backlog_limit
+*/
+static atomic_t	audit_lost = ATOMIC_INIT(0);
+
+/* Monotonically increasing sum of time the kernel has spent
+ * waiting while the backlog limit is exceeded.
+ */
+static atomic_t audit_backlog_wait_time_actual = ATOMIC_INIT(0);
+
+/* Hash for inode-based rules */
+struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
+
+static struct kmem_cache *audit_buffer_cache;
+
+/* queue msgs to send via kauditd_task */
+static struct sk_buff_head audit_queue;
+/* queue msgs due to temporary unicast send problems */
+static struct sk_buff_head audit_retry_queue;
+/* queue msgs waiting for new auditd connection */
+static struct sk_buff_head audit_hold_queue;
+
+/* queue servicing thread */
+static struct task_struct *kauditd_task;
+static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
+
+/* waitqueue for callers who are blocked on the audit backlog */
+static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
+
+static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
+				   .mask = -1,
+				   .features = 0,
+				   .lock = 0,};
+
+static char *audit_feature_names[2] = {
+	"only_unset_loginuid",
+	"loginuid_immutable",
+};
+
+/**
+ * struct audit_ctl_mutex - serialize requests from userspace
+ * @lock: the mutex used for locking
+ * @owner: the task which owns the lock
+ *
+ * Description:
+ * This is the lock struct used to ensure we only process userspace requests
+ * in an orderly fashion.  We can't simply use a mutex/lock here because we
+ * need to track lock ownership so we don't end up blocking the lock owner in
+ * audit_log_start() or similar.
+ */
+static struct audit_ctl_mutex {
+	struct mutex lock;
+	void *owner;
+} audit_cmd_mutex;
+
+/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
+ * audit records.  Since printk uses a 1024 byte buffer, this buffer
+ * should be at least that large. */
+#define AUDIT_BUFSIZ 1024
+
+/* The audit_buffer is used when formatting an audit record.  The caller
+ * locks briefly to get the record off the freelist or to allocate the
+ * buffer, and locks briefly to send the buffer to the netlink layer or
+ * to place it on a transmit queue.  Multiple audit_buffers can be in
+ * use simultaneously. */
+struct audit_buffer {
+	struct sk_buff       *skb;	/* formatted skb ready to send */
+	struct audit_context *ctx;	/* NULL or associated context */
+	gfp_t		     gfp_mask;
+};
+
+struct audit_reply {
+	__u32 portid;
+	struct net *net;
+	struct sk_buff *skb;
+};
+
+/**
+ * auditd_test_task - Check to see if a given task is an audit daemon
+ * @task: the task to check
+ *
+ * Description:
+ * Return 1 if the task is a registered audit daemon, 0 otherwise.
+ */
+int auditd_test_task(struct task_struct *task)
+{
+	int rc;
+	struct auditd_connection *ac;
+
+	rcu_read_lock();
+	ac = rcu_dereference(auditd_conn);
+	rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
+	rcu_read_unlock();
+
+	return rc;
+}
+
+/**
+ * audit_ctl_lock - Take the audit control lock
+ */
+void audit_ctl_lock(void)
+{
+	mutex_lock(&audit_cmd_mutex.lock);
+	audit_cmd_mutex.owner = current;
+}
+
+/**
+ * audit_ctl_unlock - Drop the audit control lock
+ */
+void audit_ctl_unlock(void)
+{
+	audit_cmd_mutex.owner = NULL;
+	mutex_unlock(&audit_cmd_mutex.lock);
+}
+
+/**
+ * audit_ctl_owner_current - Test to see if the current task owns the lock
+ *
+ * Description:
+ * Return true if the current task owns the audit control lock, false if it
+ * doesn't own the lock.
+ */
+static bool audit_ctl_owner_current(void)
+{
+	return (current == audit_cmd_mutex.owner);
+}
+
+/**
+ * auditd_pid_vnr - Return the auditd PID relative to the namespace
+ *
+ * Description:
+ * Returns the PID in relation to the namespace, 0 on failure.
+ */
+static pid_t auditd_pid_vnr(void)
+{
+	pid_t pid;
+	const struct auditd_connection *ac;
+
+	rcu_read_lock();
+	ac = rcu_dereference(auditd_conn);
+	if (!ac || !ac->pid)
+		pid = 0;
+	else
+		pid = pid_vnr(ac->pid);
+	rcu_read_unlock();
+
+	return pid;
+}
+
+/**
+ * audit_get_sk - Return the audit socket for the given network namespace
+ * @net: the destination network namespace
+ *
+ * Description:
+ * Returns the sock pointer if valid, NULL otherwise.  The caller must ensure
+ * that a reference is held for the network namespace while the sock is in use.
+ */
+static struct sock *audit_get_sk(const struct net *net)
+{
+	struct audit_net *aunet;
+
+	if (!net)
+		return NULL;
+
+	aunet = net_generic(net, audit_net_id);
+	return aunet->sk;
+}
+
+void audit_panic(const char *message)
+{
+	switch (audit_failure) {
+	case AUDIT_FAIL_SILENT:
+		break;
+	case AUDIT_FAIL_PRINTK:
+		if (printk_ratelimit())
+			pr_err("%s\n", message);
+		break;
+	case AUDIT_FAIL_PANIC:
+		panic("audit: %s\n", message);
+		break;
+	}
+}
+
+static inline int audit_rate_check(void)
+{
+	static unsigned long	last_check = 0;
+	static int		messages   = 0;
+	static DEFINE_SPINLOCK(lock);
+	unsigned long		flags;
+	unsigned long		now;
+	int			retval	   = 0;
+
+	if (!audit_rate_limit) return 1;
+
+	spin_lock_irqsave(&lock, flags);
+	if (++messages < audit_rate_limit) {
+		retval = 1;
+	} else {
+		now = jiffies;
+		if (time_after(now, last_check + HZ)) {
+			last_check = now;
+			messages   = 0;
+			retval     = 1;
+		}
+	}
+	spin_unlock_irqrestore(&lock, flags);
+
+	return retval;
+}
+
+/**
+ * audit_log_lost - conditionally log lost audit message event
+ * @message: the message stating reason for lost audit message
+ *
+ * Emit at least 1 message per second, even if audit_rate_check is
+ * throttling.
+ * Always increment the lost messages counter.
+*/
+void audit_log_lost(const char *message)
+{
+	static unsigned long	last_msg = 0;
+	static DEFINE_SPINLOCK(lock);
+	unsigned long		flags;
+	unsigned long		now;
+	int			print;
+
+	atomic_inc(&audit_lost);
+
+	print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
+
+	if (!print) {
+		spin_lock_irqsave(&lock, flags);
+		now = jiffies;
+		if (time_after(now, last_msg + HZ)) {
+			print = 1;
+			last_msg = now;
+		}
+		spin_unlock_irqrestore(&lock, flags);
+	}
+
+	if (print) {
+		if (printk_ratelimit())
+			pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
+				atomic_read(&audit_lost),
+				audit_rate_limit,
+				audit_backlog_limit);
+		audit_panic(message);
+	}
+}
+
+static int audit_log_config_change(char *function_name, u32 new, u32 old,
+				   int allow_changes)
+{
+	struct audit_buffer *ab;
+	int rc = 0;
+
+	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
+	if (unlikely(!ab))
+		return rc;
+	audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
+	audit_log_session_info(ab);
+	rc = audit_log_task_context(ab);
+	if (rc)
+		allow_changes = 0; /* Something weird, deny request */
+	audit_log_format(ab, " res=%d", allow_changes);
+	audit_log_end(ab);
+	return rc;
+}
+
+static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
+{
+	int allow_changes, rc = 0;
+	u32 old = *to_change;
+
+	/* check if we are locked */
+	if (audit_enabled == AUDIT_LOCKED)
+		allow_changes = 0;
+	else
+		allow_changes = 1;
+
+	if (audit_enabled != AUDIT_OFF) {
+		rc = audit_log_config_change(function_name, new, old, allow_changes);
+		if (rc)
+			allow_changes = 0;
+	}
+
+	/* If we are allowed, make the change */
+	if (allow_changes == 1)
+		*to_change = new;
+	/* Not allowed, update reason */
+	else if (rc == 0)
+		rc = -EPERM;
+	return rc;
+}
+
+static int audit_set_rate_limit(u32 limit)
+{
+	return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
+}
+
+static int audit_set_backlog_limit(u32 limit)
+{
+	return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
+}
+
+static int audit_set_backlog_wait_time(u32 timeout)
+{
+	return audit_do_config_change("audit_backlog_wait_time",
+				      &audit_backlog_wait_time, timeout);
+}
+
+static int audit_set_enabled(u32 state)
+{
+	int rc;
+	if (state > AUDIT_LOCKED)
+		return -EINVAL;
+
+	rc =  audit_do_config_change("audit_enabled", &audit_enabled, state);
+	if (!rc)
+		audit_ever_enabled |= !!state;
+
+	return rc;
+}
+
+static int audit_set_failure(u32 state)
+{
+	if (state != AUDIT_FAIL_SILENT
+	    && state != AUDIT_FAIL_PRINTK
+	    && state != AUDIT_FAIL_PANIC)
+		return -EINVAL;
+
+	return audit_do_config_change("audit_failure", &audit_failure, state);
+}
+
+/**
+ * auditd_conn_free - RCU helper to release an auditd connection struct
+ * @rcu: RCU head
+ *
+ * Description:
+ * Drop any references inside the auditd connection tracking struct and free
+ * the memory.
+ */
+static void auditd_conn_free(struct rcu_head *rcu)
+{
+	struct auditd_connection *ac;
+
+	ac = container_of(rcu, struct auditd_connection, rcu);
+	put_pid(ac->pid);
+	put_net(ac->net);
+	kfree(ac);
+}
+
+/**
+ * auditd_set - Set/Reset the auditd connection state
+ * @pid: auditd PID
+ * @portid: auditd netlink portid
+ * @net: auditd network namespace pointer
+ *
+ * Description:
+ * This function will obtain and drop network namespace references as
+ * necessary.  Returns zero on success, negative values on failure.
+ */
+static int auditd_set(struct pid *pid, u32 portid, struct net *net)
+{
+	unsigned long flags;
+	struct auditd_connection *ac_old, *ac_new;
+
+	if (!pid || !net)
+		return -EINVAL;
+
+	ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
+	if (!ac_new)
+		return -ENOMEM;
+	ac_new->pid = get_pid(pid);
+	ac_new->portid = portid;
+	ac_new->net = get_net(net);
+
+	spin_lock_irqsave(&auditd_conn_lock, flags);
+	ac_old = rcu_dereference_protected(auditd_conn,
+					   lockdep_is_held(&auditd_conn_lock));
+	rcu_assign_pointer(auditd_conn, ac_new);
+	spin_unlock_irqrestore(&auditd_conn_lock, flags);
+
+	if (ac_old)
+		call_rcu(&ac_old->rcu, auditd_conn_free);
+
+	return 0;
+}
+
+/**
+ * kauditd_printk_skb - Print the audit record to the ring buffer
+ * @skb: audit record
+ *
+ * Whatever the reason, this packet may not make it to the auditd connection
+ * so write it via printk so the information isn't completely lost.
+ */
+static void kauditd_printk_skb(struct sk_buff *skb)
+{
+	struct nlmsghdr *nlh = nlmsg_hdr(skb);
+	char *data = nlmsg_data(nlh);
+
+	if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
+		pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
+}
+
+/**
+ * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
+ * @skb: audit record
+ * @error: error code (unused)
+ *
+ * Description:
+ * This should only be used by the kauditd_thread when it fails to flush the
+ * hold queue.
+ */
+static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error)
+{
+	/* put the record back in the queue */
+	skb_queue_tail(&audit_hold_queue, skb);
+}
+
+/**
+ * kauditd_hold_skb - Queue an audit record, waiting for auditd
+ * @skb: audit record
+ * @error: error code
+ *
+ * Description:
+ * Queue the audit record, waiting for an instance of auditd.  When this
+ * function is called we haven't given up yet on sending the record, but things
+ * are not looking good.  The first thing we want to do is try to write the
+ * record via printk and then see if we want to try and hold on to the record
+ * and queue it, if we have room.  If we want to hold on to the record, but we
+ * don't have room, record a record lost message.
+ */
+static void kauditd_hold_skb(struct sk_buff *skb, int error)
+{
+	/* at this point it is uncertain if we will ever send this to auditd so
+	 * try to send the message via printk before we go any further */
+	kauditd_printk_skb(skb);
+
+	/* can we just silently drop the message? */
+	if (!audit_default)
+		goto drop;
+
+	/* the hold queue is only for when the daemon goes away completely,
+	 * not -EAGAIN failures; if we are in a -EAGAIN state requeue the
+	 * record on the retry queue unless it's full, in which case drop it
+	 */
+	if (error == -EAGAIN) {
+		if (!audit_backlog_limit ||
+		    skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
+			skb_queue_tail(&audit_retry_queue, skb);
+			return;
+		}
+		audit_log_lost("kauditd retry queue overflow");
+		goto drop;
+	}
+
+	/* if we have room in the hold queue, queue the message */
+	if (!audit_backlog_limit ||
+	    skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
+		skb_queue_tail(&audit_hold_queue, skb);
+		return;
+	}
+
+	/* we have no other options - drop the message */
+	audit_log_lost("kauditd hold queue overflow");
+drop:
+	kfree_skb(skb);
+}
+
+/**
+ * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
+ * @skb: audit record
+ * @error: error code (unused)
+ *
+ * Description:
+ * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
+ * but for some reason we are having problems sending it audit records so
+ * queue the given record and attempt to resend.
+ */
+static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error)
+{
+	if (!audit_backlog_limit ||
+	    skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
+		skb_queue_tail(&audit_retry_queue, skb);
+		return;
+	}
+
+	/* we have to drop the record, send it via printk as a last effort */
+	kauditd_printk_skb(skb);
+	audit_log_lost("kauditd retry queue overflow");
+	kfree_skb(skb);
+}
+
+/**
+ * auditd_reset - Disconnect the auditd connection
+ * @ac: auditd connection state
+ *
+ * Description:
+ * Break the auditd/kauditd connection and move all the queued records into the
+ * hold queue in case auditd reconnects.  It is important to note that the @ac
+ * pointer should never be dereferenced inside this function as it may be NULL
+ * or invalid, you can only compare the memory address!  If @ac is NULL then
+ * the connection will always be reset.
+ */
+static void auditd_reset(const struct auditd_connection *ac)
+{
+	unsigned long flags;
+	struct sk_buff *skb;
+	struct auditd_connection *ac_old;
+
+	/* if it isn't already broken, break the connection */
+	spin_lock_irqsave(&auditd_conn_lock, flags);
+	ac_old = rcu_dereference_protected(auditd_conn,
+					   lockdep_is_held(&auditd_conn_lock));
+	if (ac && ac != ac_old) {
+		/* someone already registered a new auditd connection */
+		spin_unlock_irqrestore(&auditd_conn_lock, flags);
+		return;
+	}
+	rcu_assign_pointer(auditd_conn, NULL);
+	spin_unlock_irqrestore(&auditd_conn_lock, flags);
+
+	if (ac_old)
+		call_rcu(&ac_old->rcu, auditd_conn_free);
+
+	/* flush the retry queue to the hold queue, but don't touch the main
+	 * queue since we need to process that normally for multicast */
+	while ((skb = skb_dequeue(&audit_retry_queue)))
+		kauditd_hold_skb(skb, -ECONNREFUSED);
+}
+
+/**
+ * auditd_send_unicast_skb - Send a record via unicast to auditd
+ * @skb: audit record
+ *
+ * Description:
+ * Send a skb to the audit daemon, returns positive/zero values on success and
+ * negative values on failure; in all cases the skb will be consumed by this
+ * function.  If the send results in -ECONNREFUSED the connection with auditd
+ * will be reset.  This function may sleep so callers should not hold any locks
+ * where this would cause a problem.
+ */
+static int auditd_send_unicast_skb(struct sk_buff *skb)
+{
+	int rc;
+	u32 portid;
+	struct net *net;
+	struct sock *sk;
+	struct auditd_connection *ac;
+
+	/* NOTE: we can't call netlink_unicast while in the RCU section so
+	 *       take a reference to the network namespace and grab local
+	 *       copies of the namespace, the sock, and the portid; the
+	 *       namespace and sock aren't going to go away while we hold a
+	 *       reference and if the portid does become invalid after the RCU
+	 *       section netlink_unicast() should safely return an error */
+
+	rcu_read_lock();
+	ac = rcu_dereference(auditd_conn);
+	if (!ac) {
+		rcu_read_unlock();
+		kfree_skb(skb);
+		rc = -ECONNREFUSED;
+		goto err;
+	}
+	net = get_net(ac->net);
+	sk = audit_get_sk(net);
+	portid = ac->portid;
+	rcu_read_unlock();
+
+	rc = netlink_unicast(sk, skb, portid, 0);
+	put_net(net);
+	if (rc < 0)
+		goto err;
+
+	return rc;
+
+err:
+	if (ac && rc == -ECONNREFUSED)
+		auditd_reset(ac);
+	return rc;
+}
+
+/**
+ * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
+ * @sk: the sending sock
+ * @portid: the netlink destination
+ * @queue: the skb queue to process
+ * @retry_limit: limit on number of netlink unicast failures
+ * @skb_hook: per-skb hook for additional processing
+ * @err_hook: hook called if the skb fails the netlink unicast send
+ *
+ * Description:
+ * Run through the given queue and attempt to send the audit records to auditd,
+ * returns zero on success, negative values on failure.  It is up to the caller
+ * to ensure that the @sk is valid for the duration of this function.
+ *
+ */
+static int kauditd_send_queue(struct sock *sk, u32 portid,
+			      struct sk_buff_head *queue,
+			      unsigned int retry_limit,
+			      void (*skb_hook)(struct sk_buff *skb),
+			      void (*err_hook)(struct sk_buff *skb, int error))
+{
+	int rc = 0;
+	struct sk_buff *skb = NULL;
+	struct sk_buff *skb_tail;
+	unsigned int failed = 0;
+
+	/* NOTE: kauditd_thread takes care of all our locking, we just use
+	 *       the netlink info passed to us (e.g. sk and portid) */
+
+	skb_tail = skb_peek_tail(queue);
+	while ((skb != skb_tail) && (skb = skb_dequeue(queue))) {
+		/* call the skb_hook for each skb we touch */
+		if (skb_hook)
+			(*skb_hook)(skb);
+
+		/* can we send to anyone via unicast? */
+		if (!sk) {
+			if (err_hook)
+				(*err_hook)(skb, -ECONNREFUSED);
+			continue;
+		}
+
+retry:
+		/* grab an extra skb reference in case of error */
+		skb_get(skb);
+		rc = netlink_unicast(sk, skb, portid, 0);
+		if (rc < 0) {
+			/* send failed - try a few times unless fatal error */
+			if (++failed >= retry_limit ||
+			    rc == -ECONNREFUSED || rc == -EPERM) {
+				sk = NULL;
+				if (err_hook)
+					(*err_hook)(skb, rc);
+				if (rc == -EAGAIN)
+					rc = 0;
+				/* continue to drain the queue */
+				continue;
+			} else
+				goto retry;
+		} else {
+			/* skb sent - drop the extra reference and continue */
+			consume_skb(skb);
+			failed = 0;
+		}
+	}
+
+	return (rc >= 0 ? 0 : rc);
+}
+
+/*
+ * kauditd_send_multicast_skb - Send a record to any multicast listeners
+ * @skb: audit record
+ *
+ * Description:
+ * Write a multicast message to anyone listening in the initial network
+ * namespace.  This function doesn't consume an skb as might be expected since
+ * it has to copy it anyways.
+ */
+static void kauditd_send_multicast_skb(struct sk_buff *skb)
+{
+	struct sk_buff *copy;
+	struct sock *sock = audit_get_sk(&init_net);
+	struct nlmsghdr *nlh;
+
+	/* NOTE: we are not taking an additional reference for init_net since
+	 *       we don't have to worry about it going away */
+
+	if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
+		return;
+
+	/*
+	 * The seemingly wasteful skb_copy() rather than bumping the refcount
+	 * using skb_get() is necessary because non-standard mods are made to
+	 * the skb by the original kaudit unicast socket send routine.  The
+	 * existing auditd daemon assumes this breakage.  Fixing this would
+	 * require co-ordinating a change in the established protocol between
+	 * the kaudit kernel subsystem and the auditd userspace code.  There is
+	 * no reason for new multicast clients to continue with this
+	 * non-compliance.
+	 */
+	copy = skb_copy(skb, GFP_KERNEL);
+	if (!copy)
+		return;
+	nlh = nlmsg_hdr(copy);
+	nlh->nlmsg_len = skb->len;
+
+	nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
+}
+
+/**
+ * kauditd_thread - Worker thread to send audit records to userspace
+ * @dummy: unused
+ */
+static int kauditd_thread(void *dummy)
+{
+	int rc;
+	u32 portid = 0;
+	struct net *net = NULL;
+	struct sock *sk = NULL;
+	struct auditd_connection *ac;
+
+#define UNICAST_RETRIES 5
+
+	set_freezable();
+	while (!kthread_should_stop()) {
+		/* NOTE: see the lock comments in auditd_send_unicast_skb() */
+		rcu_read_lock();
+		ac = rcu_dereference(auditd_conn);
+		if (!ac) {
+			rcu_read_unlock();
+			goto main_queue;
+		}
+		net = get_net(ac->net);
+		sk = audit_get_sk(net);
+		portid = ac->portid;
+		rcu_read_unlock();
+
+		/* attempt to flush the hold queue */
+		rc = kauditd_send_queue(sk, portid,
+					&audit_hold_queue, UNICAST_RETRIES,
+					NULL, kauditd_rehold_skb);
+		if (rc < 0) {
+			sk = NULL;
+			auditd_reset(ac);
+			goto main_queue;
+		}
+
+		/* attempt to flush the retry queue */
+		rc = kauditd_send_queue(sk, portid,
+					&audit_retry_queue, UNICAST_RETRIES,
+					NULL, kauditd_hold_skb);
+		if (rc < 0) {
+			sk = NULL;
+			auditd_reset(ac);
+			goto main_queue;
+		}
+
+main_queue:
+		/* process the main queue - do the multicast send and attempt
+		 * unicast, dump failed record sends to the retry queue; if
+		 * sk == NULL due to previous failures we will just do the
+		 * multicast send and move the record to the hold queue */
+		rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
+					kauditd_send_multicast_skb,
+					(sk ?
+					 kauditd_retry_skb : kauditd_hold_skb));
+		if (ac && rc < 0)
+			auditd_reset(ac);
+		sk = NULL;
+
+		/* drop our netns reference, no auditd sends past this line */
+		if (net) {
+			put_net(net);
+			net = NULL;
+		}
+
+		/* we have processed all the queues so wake everyone */
+		wake_up(&audit_backlog_wait);
+
+		/* NOTE: we want to wake up if there is anything on the queue,
+		 *       regardless of if an auditd is connected, as we need to
+		 *       do the multicast send and rotate records from the
+		 *       main queue to the retry/hold queues */
+		wait_event_freezable(kauditd_wait,
+				     (skb_queue_len(&audit_queue) ? 1 : 0));
+	}
+
+	return 0;
+}
+
+int audit_send_list_thread(void *_dest)
+{
+	struct audit_netlink_list *dest = _dest;
+	struct sk_buff *skb;
+	struct sock *sk = audit_get_sk(dest->net);
+
+	/* wait for parent to finish and send an ACK */
+	audit_ctl_lock();
+	audit_ctl_unlock();
+
+	while ((skb = __skb_dequeue(&dest->q)) != NULL)
+		netlink_unicast(sk, skb, dest->portid, 0);
+
+	put_net(dest->net);
+	kfree(dest);
+
+	return 0;
+}
+
+struct sk_buff *audit_make_reply(int seq, int type, int done,
+				 int multi, const void *payload, int size)
+{
+	struct sk_buff	*skb;
+	struct nlmsghdr	*nlh;
+	void		*data;
+	int		flags = multi ? NLM_F_MULTI : 0;
+	int		t     = done  ? NLMSG_DONE  : type;
+
+	skb = nlmsg_new(size, GFP_KERNEL);
+	if (!skb)
+		return NULL;
+
+	nlh	= nlmsg_put(skb, 0, seq, t, size, flags);
+	if (!nlh)
+		goto out_kfree_skb;
+	data = nlmsg_data(nlh);
+	memcpy(data, payload, size);
+	return skb;
+
+out_kfree_skb:
+	kfree_skb(skb);
+	return NULL;
+}
+
+static void audit_free_reply(struct audit_reply *reply)
+{
+	if (!reply)
+		return;
+
+	kfree_skb(reply->skb);
+	if (reply->net)
+		put_net(reply->net);
+	kfree(reply);
+}
+
+static int audit_send_reply_thread(void *arg)
+{
+	struct audit_reply *reply = (struct audit_reply *)arg;
+
+	audit_ctl_lock();
+	audit_ctl_unlock();
+
+	/* Ignore failure. It'll only happen if the sender goes away,
+	   because our timeout is set to infinite. */
+	netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
+	reply->skb = NULL;
+	audit_free_reply(reply);
+	return 0;
+}
+
+/**
+ * audit_send_reply - send an audit reply message via netlink
+ * @request_skb: skb of request we are replying to (used to target the reply)
+ * @seq: sequence number
+ * @type: audit message type
+ * @done: done (last) flag
+ * @multi: multi-part message flag
+ * @payload: payload data
+ * @size: payload size
+ *
+ * Allocates a skb, builds the netlink message, and sends it to the port id.
+ */
+static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
+			     int multi, const void *payload, int size)
+{
+	struct task_struct *tsk;
+	struct audit_reply *reply;
+
+	reply = kzalloc(sizeof(*reply), GFP_KERNEL);
+	if (!reply)
+		return;
+
+	reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
+	if (!reply->skb)
+		goto err;
+	reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
+	reply->portid = NETLINK_CB(request_skb).portid;
+
+	tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
+	if (IS_ERR(tsk))
+		goto err;
+
+	return;
+
+err:
+	audit_free_reply(reply);
+}
+
+/*
+ * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
+ * control messages.
+ */
+static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
+{
+	int err = 0;
+
+	/* Only support initial user namespace for now. */
+	/*
+	 * We return ECONNREFUSED because it tricks userspace into thinking
+	 * that audit was not configured into the kernel.  Lots of users
+	 * configure their PAM stack (because that's what the distro does)
+	 * to reject login if unable to send messages to audit.  If we return
+	 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
+	 * configured in and will let login proceed.  If we return EPERM
+	 * userspace will reject all logins.  This should be removed when we
+	 * support non init namespaces!!
+	 */
+	if (current_user_ns() != &init_user_ns)
+		return -ECONNREFUSED;
+
+	switch (msg_type) {
+	case AUDIT_LIST:
+	case AUDIT_ADD:
+	case AUDIT_DEL:
+		return -EOPNOTSUPP;
+	case AUDIT_GET:
+	case AUDIT_SET:
+	case AUDIT_GET_FEATURE:
+	case AUDIT_SET_FEATURE:
+	case AUDIT_LIST_RULES:
+	case AUDIT_ADD_RULE:
+	case AUDIT_DEL_RULE:
+	case AUDIT_SIGNAL_INFO:
+	case AUDIT_TTY_GET:
+	case AUDIT_TTY_SET:
+	case AUDIT_TRIM:
+	case AUDIT_MAKE_EQUIV:
+		/* Only support auditd and auditctl in initial pid namespace
+		 * for now. */
+		if (task_active_pid_ns(current) != &init_pid_ns)
+			return -EPERM;
+
+		if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
+			err = -EPERM;
+		break;
+	case AUDIT_USER:
+	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
+	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
+		if (!netlink_capable(skb, CAP_AUDIT_WRITE))
+			err = -EPERM;
+		break;
+	default:  /* bad msg */
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+static void audit_log_common_recv_msg(struct audit_context *context,
+					struct audit_buffer **ab, u16 msg_type)
+{
+	uid_t uid = from_kuid(&init_user_ns, current_uid());
+	pid_t pid = task_tgid_nr(current);
+
+	if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
+		*ab = NULL;
+		return;
+	}
+
+	*ab = audit_log_start(context, GFP_KERNEL, msg_type);
+	if (unlikely(!*ab))
+		return;
+	audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
+	audit_log_session_info(*ab);
+	audit_log_task_context(*ab);
+}
+
+static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
+					   u16 msg_type)
+{
+	audit_log_common_recv_msg(NULL, ab, msg_type);
+}
+
+static int is_audit_feature_set(int i)
+{
+	return af.features & AUDIT_FEATURE_TO_MASK(i);
+}
+
+
+static int audit_get_feature(struct sk_buff *skb)
+{
+	u32 seq;
+
+	seq = nlmsg_hdr(skb)->nlmsg_seq;
+
+	audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
+
+	return 0;
+}
+
+static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
+				     u32 old_lock, u32 new_lock, int res)
+{
+	struct audit_buffer *ab;
+
+	if (audit_enabled == AUDIT_OFF)
+		return;
+
+	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
+	if (!ab)
+		return;
+	audit_log_task_info(ab);
+	audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
+			 audit_feature_names[which], !!old_feature, !!new_feature,
+			 !!old_lock, !!new_lock, res);
+	audit_log_end(ab);
+}
+
+static int audit_set_feature(struct audit_features *uaf)
+{
+	int i;
+
+	BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
+
+	/* if there is ever a version 2 we should handle that here */
+
+	for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
+		u32 feature = AUDIT_FEATURE_TO_MASK(i);
+		u32 old_feature, new_feature, old_lock, new_lock;
+
+		/* if we are not changing this feature, move along */
+		if (!(feature & uaf->mask))
+			continue;
+
+		old_feature = af.features & feature;
+		new_feature = uaf->features & feature;
+		new_lock = (uaf->lock | af.lock) & feature;
+		old_lock = af.lock & feature;
+
+		/* are we changing a locked feature? */
+		if (old_lock && (new_feature != old_feature)) {
+			audit_log_feature_change(i, old_feature, new_feature,
+						 old_lock, new_lock, 0);
+			return -EPERM;
+		}
+	}
+	/* nothing invalid, do the changes */
+	for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
+		u32 feature = AUDIT_FEATURE_TO_MASK(i);
+		u32 old_feature, new_feature, old_lock, new_lock;
+
+		/* if we are not changing this feature, move along */
+		if (!(feature & uaf->mask))
+			continue;
+
+		old_feature = af.features & feature;
+		new_feature = uaf->features & feature;
+		old_lock = af.lock & feature;
+		new_lock = (uaf->lock | af.lock) & feature;
+
+		if (new_feature != old_feature)
+			audit_log_feature_change(i, old_feature, new_feature,
+						 old_lock, new_lock, 1);
+
+		if (new_feature)
+			af.features |= feature;
+		else
+			af.features &= ~feature;
+		af.lock |= new_lock;
+	}
+
+	return 0;
+}
+
+static int audit_replace(struct pid *pid)
+{
+	pid_t pvnr;
+	struct sk_buff *skb;
+
+	pvnr = pid_vnr(pid);
+	skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
+	if (!skb)
+		return -ENOMEM;
+	return auditd_send_unicast_skb(skb);
+}
+
+static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
+{
+	u32			seq;
+	void			*data;
+	int			data_len;
+	int			err;
+	struct audit_buffer	*ab;
+	u16			msg_type = nlh->nlmsg_type;
+	struct audit_sig_info   *sig_data;
+	char			*ctx = NULL;
+	u32			len;
+
+	err = audit_netlink_ok(skb, msg_type);
+	if (err)
+		return err;
+
+	seq  = nlh->nlmsg_seq;
+	data = nlmsg_data(nlh);
+	data_len = nlmsg_len(nlh);
+
+	switch (msg_type) {
+	case AUDIT_GET: {
+		struct audit_status	s;
+		memset(&s, 0, sizeof(s));
+		s.enabled		   = audit_enabled;
+		s.failure		   = audit_failure;
+		/* NOTE: use pid_vnr() so the PID is relative to the current
+		 *       namespace */
+		s.pid			   = auditd_pid_vnr();
+		s.rate_limit		   = audit_rate_limit;
+		s.backlog_limit		   = audit_backlog_limit;
+		s.lost			   = atomic_read(&audit_lost);
+		s.backlog		   = skb_queue_len(&audit_queue);
+		s.feature_bitmap	   = AUDIT_FEATURE_BITMAP_ALL;
+		s.backlog_wait_time	   = audit_backlog_wait_time;
+		s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual);
+		audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
+		break;
+	}
+	case AUDIT_SET: {
+		struct audit_status	s;
+		memset(&s, 0, sizeof(s));
+		/* guard against past and future API changes */
+		memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
+		if (s.mask & AUDIT_STATUS_ENABLED) {
+			err = audit_set_enabled(s.enabled);
+			if (err < 0)
+				return err;
+		}
+		if (s.mask & AUDIT_STATUS_FAILURE) {
+			err = audit_set_failure(s.failure);
+			if (err < 0)
+				return err;
+		}
+		if (s.mask & AUDIT_STATUS_PID) {
+			/* NOTE: we are using the vnr PID functions below
+			 *       because the s.pid value is relative to the
+			 *       namespace of the caller; at present this
+			 *       doesn't matter much since you can really only
+			 *       run auditd from the initial pid namespace, but
+			 *       something to keep in mind if this changes */
+			pid_t new_pid = s.pid;
+			pid_t auditd_pid;
+			struct pid *req_pid = task_tgid(current);
+
+			/* Sanity check - PID values must match. Setting
+			 * pid to 0 is how auditd ends auditing. */
+			if (new_pid && (new_pid != pid_vnr(req_pid)))
+				return -EINVAL;
+
+			/* test the auditd connection */
+			audit_replace(req_pid);
+
+			auditd_pid = auditd_pid_vnr();
+			if (auditd_pid) {
+				/* replacing a healthy auditd is not allowed */
+				if (new_pid) {
+					audit_log_config_change("audit_pid",
+							new_pid, auditd_pid, 0);
+					return -EEXIST;
+				}
+				/* only current auditd can unregister itself */
+				if (pid_vnr(req_pid) != auditd_pid) {
+					audit_log_config_change("audit_pid",
+							new_pid, auditd_pid, 0);
+					return -EACCES;
+				}
+			}
+
+			if (new_pid) {
+				/* register a new auditd connection */
+				err = auditd_set(req_pid,
+						 NETLINK_CB(skb).portid,
+						 sock_net(NETLINK_CB(skb).sk));
+				if (audit_enabled != AUDIT_OFF)
+					audit_log_config_change("audit_pid",
+								new_pid,
+								auditd_pid,
+								err ? 0 : 1);
+				if (err)
+					return err;
+
+				/* try to process any backlog */
+				wake_up_interruptible(&kauditd_wait);
+			} else {
+				if (audit_enabled != AUDIT_OFF)
+					audit_log_config_change("audit_pid",
+								new_pid,
+								auditd_pid, 1);
+
+				/* unregister the auditd connection */
+				auditd_reset(NULL);
+			}
+		}
+		if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
+			err = audit_set_rate_limit(s.rate_limit);
+			if (err < 0)
+				return err;
+		}
+		if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
+			err = audit_set_backlog_limit(s.backlog_limit);
+			if (err < 0)
+				return err;
+		}
+		if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
+			if (sizeof(s) > (size_t)nlh->nlmsg_len)
+				return -EINVAL;
+			if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
+				return -EINVAL;
+			err = audit_set_backlog_wait_time(s.backlog_wait_time);
+			if (err < 0)
+				return err;
+		}
+		if (s.mask == AUDIT_STATUS_LOST) {
+			u32 lost = atomic_xchg(&audit_lost, 0);
+
+			audit_log_config_change("lost", 0, lost, 1);
+			return lost;
+		}
+		if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) {
+			u32 actual = atomic_xchg(&audit_backlog_wait_time_actual, 0);
+
+			audit_log_config_change("backlog_wait_time_actual", 0, actual, 1);
+			return actual;
+		}
+		break;
+	}
+	case AUDIT_GET_FEATURE:
+		err = audit_get_feature(skb);
+		if (err)
+			return err;
+		break;
+	case AUDIT_SET_FEATURE:
+		if (data_len < sizeof(struct audit_features))
+			return -EINVAL;
+		err = audit_set_feature(data);
+		if (err)
+			return err;
+		break;
+	case AUDIT_USER:
+	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
+	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
+		if (!audit_enabled && msg_type != AUDIT_USER_AVC)
+			return 0;
+		/* exit early if there isn't at least one character to print */
+		if (data_len < 2)
+			return -EINVAL;
+
+		err = audit_filter(msg_type, AUDIT_FILTER_USER);
+		if (err == 1) { /* match or error */
+			char *str = data;
+
+			err = 0;
+			if (msg_type == AUDIT_USER_TTY) {
+				err = tty_audit_push();
+				if (err)
+					break;
+			}
+			audit_log_user_recv_msg(&ab, msg_type);
+			if (msg_type != AUDIT_USER_TTY) {
+				/* ensure NULL termination */
+				str[data_len - 1] = '\0';
+				audit_log_format(ab, " msg='%.*s'",
+						 AUDIT_MESSAGE_TEXT_MAX,
+						 str);
+			} else {
+				audit_log_format(ab, " data=");
+				if (str[data_len - 1] == '\0')
+					data_len--;
+				audit_log_n_untrustedstring(ab, str, data_len);
+			}
+			audit_log_end(ab);
+		}
+		break;
+	case AUDIT_ADD_RULE:
+	case AUDIT_DEL_RULE:
+		if (data_len < sizeof(struct audit_rule_data))
+			return -EINVAL;
+		if (audit_enabled == AUDIT_LOCKED) {
+			audit_log_common_recv_msg(audit_context(), &ab,
+						  AUDIT_CONFIG_CHANGE);
+			audit_log_format(ab, " op=%s audit_enabled=%d res=0",
+					 msg_type == AUDIT_ADD_RULE ?
+						"add_rule" : "remove_rule",
+					 audit_enabled);
+			audit_log_end(ab);
+			return -EPERM;
+		}
+		err = audit_rule_change(msg_type, seq, data, data_len);
+		break;
+	case AUDIT_LIST_RULES:
+		err = audit_list_rules_send(skb, seq);
+		break;
+	case AUDIT_TRIM:
+		audit_trim_trees();
+		audit_log_common_recv_msg(audit_context(), &ab,
+					  AUDIT_CONFIG_CHANGE);
+		audit_log_format(ab, " op=trim res=1");
+		audit_log_end(ab);
+		break;
+	case AUDIT_MAKE_EQUIV: {
+		void *bufp = data;
+		u32 sizes[2];
+		size_t msglen = data_len;
+		char *old, *new;
+
+		err = -EINVAL;
+		if (msglen < 2 * sizeof(u32))
+			break;
+		memcpy(sizes, bufp, 2 * sizeof(u32));
+		bufp += 2 * sizeof(u32);
+		msglen -= 2 * sizeof(u32);
+		old = audit_unpack_string(&bufp, &msglen, sizes[0]);
+		if (IS_ERR(old)) {
+			err = PTR_ERR(old);
+			break;
+		}
+		new = audit_unpack_string(&bufp, &msglen, sizes[1]);
+		if (IS_ERR(new)) {
+			err = PTR_ERR(new);
+			kfree(old);
+			break;
+		}
+		/* OK, here comes... */
+		err = audit_tag_tree(old, new);
+
+		audit_log_common_recv_msg(audit_context(), &ab,
+					  AUDIT_CONFIG_CHANGE);
+		audit_log_format(ab, " op=make_equiv old=");
+		audit_log_untrustedstring(ab, old);
+		audit_log_format(ab, " new=");
+		audit_log_untrustedstring(ab, new);
+		audit_log_format(ab, " res=%d", !err);
+		audit_log_end(ab);
+		kfree(old);
+		kfree(new);
+		break;
+	}
+	case AUDIT_SIGNAL_INFO:
+		len = 0;
+		if (audit_sig_sid) {
+			err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
+			if (err)
+				return err;
+		}
+		sig_data = kmalloc(struct_size(sig_data, ctx, len), GFP_KERNEL);
+		if (!sig_data) {
+			if (audit_sig_sid)
+				security_release_secctx(ctx, len);
+			return -ENOMEM;
+		}
+		sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
+		sig_data->pid = audit_sig_pid;
+		if (audit_sig_sid) {
+			memcpy(sig_data->ctx, ctx, len);
+			security_release_secctx(ctx, len);
+		}
+		audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
+				 sig_data, struct_size(sig_data, ctx, len));
+		kfree(sig_data);
+		break;
+	case AUDIT_TTY_GET: {
+		struct audit_tty_status s;
+		unsigned int t;
+
+		t = READ_ONCE(current->signal->audit_tty);
+		s.enabled = t & AUDIT_TTY_ENABLE;
+		s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
+
+		audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
+		break;
+	}
+	case AUDIT_TTY_SET: {
+		struct audit_tty_status s, old;
+		struct audit_buffer	*ab;
+		unsigned int t;
+
+		memset(&s, 0, sizeof(s));
+		/* guard against past and future API changes */
+		memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
+		/* check if new data is valid */
+		if ((s.enabled != 0 && s.enabled != 1) ||
+		    (s.log_passwd != 0 && s.log_passwd != 1))
+			err = -EINVAL;
+
+		if (err)
+			t = READ_ONCE(current->signal->audit_tty);
+		else {
+			t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
+			t = xchg(&current->signal->audit_tty, t);
+		}
+		old.enabled = t & AUDIT_TTY_ENABLE;
+		old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
+
+		audit_log_common_recv_msg(audit_context(), &ab,
+					  AUDIT_CONFIG_CHANGE);
+		audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
+				 " old-log_passwd=%d new-log_passwd=%d res=%d",
+				 old.enabled, s.enabled, old.log_passwd,
+				 s.log_passwd, !err);
+		audit_log_end(ab);
+		break;
+	}
+	default:
+		err = -EINVAL;
+		break;
+	}
+
+	return err < 0 ? err : 0;
+}
+
+/**
+ * audit_receive - receive messages from a netlink control socket
+ * @skb: the message buffer
+ *
+ * Parse the provided skb and deal with any messages that may be present,
+ * malformed skbs are discarded.
+ */
+static void audit_receive(struct sk_buff  *skb)
+{
+	struct nlmsghdr *nlh;
+	/*
+	 * len MUST be signed for nlmsg_next to be able to dec it below 0
+	 * if the nlmsg_len was not aligned
+	 */
+	int len;
+	int err;
+
+	nlh = nlmsg_hdr(skb);
+	len = skb->len;
+
+	audit_ctl_lock();
+	while (nlmsg_ok(nlh, len)) {
+		err = audit_receive_msg(skb, nlh);
+		/* if err or if this message says it wants a response */
+		if (err || (nlh->nlmsg_flags & NLM_F_ACK))
+			netlink_ack(skb, nlh, err, NULL);
+
+		nlh = nlmsg_next(nlh, &len);
+	}
+	audit_ctl_unlock();
+
+	/* can't block with the ctrl lock, so penalize the sender now */
+	if (audit_backlog_limit &&
+	    (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
+		DECLARE_WAITQUEUE(wait, current);
+
+		/* wake kauditd to try and flush the queue */
+		wake_up_interruptible(&kauditd_wait);
+
+		add_wait_queue_exclusive(&audit_backlog_wait, &wait);
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		schedule_timeout(audit_backlog_wait_time);
+		remove_wait_queue(&audit_backlog_wait, &wait);
+	}
+}
+
+/* Log information about who is connecting to the audit multicast socket */
+static void audit_log_multicast(int group, const char *op, int err)
+{
+	const struct cred *cred;
+	struct tty_struct *tty;
+	char comm[sizeof(current->comm)];
+	struct audit_buffer *ab;
+
+	if (!audit_enabled)
+		return;
+
+	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER);
+	if (!ab)
+		return;
+
+	cred = current_cred();
+	tty = audit_get_tty();
+	audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u",
+			 task_pid_nr(current),
+			 from_kuid(&init_user_ns, cred->uid),
+			 from_kuid(&init_user_ns, audit_get_loginuid(current)),
+			 tty ? tty_name(tty) : "(none)",
+			 audit_get_sessionid(current));
+	audit_put_tty(tty);
+	audit_log_task_context(ab); /* subj= */
+	audit_log_format(ab, " comm=");
+	audit_log_untrustedstring(ab, get_task_comm(comm, current));
+	audit_log_d_path_exe(ab, current->mm); /* exe= */
+	audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err);
+	audit_log_end(ab);
+}
+
+/* Run custom bind function on netlink socket group connect or bind requests. */
+static int audit_multicast_bind(struct net *net, int group)
+{
+	int err = 0;
+
+	if (!capable(CAP_AUDIT_READ))
+		err = -EPERM;
+	audit_log_multicast(group, "connect", err);
+	return err;
+}
+
+static void audit_multicast_unbind(struct net *net, int group)
+{
+	audit_log_multicast(group, "disconnect", 0);
+}
+
+static int __net_init audit_net_init(struct net *net)
+{
+	struct netlink_kernel_cfg cfg = {
+		.input	= audit_receive,
+		.bind	= audit_multicast_bind,
+		.unbind	= audit_multicast_unbind,
+		.flags	= NL_CFG_F_NONROOT_RECV,
+		.groups	= AUDIT_NLGRP_MAX,
+	};
+
+	struct audit_net *aunet = net_generic(net, audit_net_id);
+
+	aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
+	if (aunet->sk == NULL) {
+		audit_panic("cannot initialize netlink socket in namespace");
+		return -ENOMEM;
+	}
+	/* limit the timeout in case auditd is blocked/stopped */
+	aunet->sk->sk_sndtimeo = HZ / 10;
+
+	return 0;
+}
+
+static void __net_exit audit_net_exit(struct net *net)
+{
+	struct audit_net *aunet = net_generic(net, audit_net_id);
+
+	/* NOTE: you would think that we would want to check the auditd
+	 * connection and potentially reset it here if it lives in this
+	 * namespace, but since the auditd connection tracking struct holds a
+	 * reference to this namespace (see auditd_set()) we are only ever
+	 * going to get here after that connection has been released */
+
+	netlink_kernel_release(aunet->sk);
+}
+
+static struct pernet_operations audit_net_ops __net_initdata = {
+	.init = audit_net_init,
+	.exit = audit_net_exit,
+	.id = &audit_net_id,
+	.size = sizeof(struct audit_net),
+};
+
+/* Initialize audit support at boot time. */
+static int __init audit_init(void)
+{
+	int i;
+
+	if (audit_initialized == AUDIT_DISABLED)
+		return 0;
+
+	audit_buffer_cache = kmem_cache_create("audit_buffer",
+					       sizeof(struct audit_buffer),
+					       0, SLAB_PANIC, NULL);
+
+	skb_queue_head_init(&audit_queue);
+	skb_queue_head_init(&audit_retry_queue);
+	skb_queue_head_init(&audit_hold_queue);
+
+	for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
+		INIT_LIST_HEAD(&audit_inode_hash[i]);
+
+	mutex_init(&audit_cmd_mutex.lock);
+	audit_cmd_mutex.owner = NULL;
+
+	pr_info("initializing netlink subsys (%s)\n",
+		audit_default ? "enabled" : "disabled");
+	register_pernet_subsys(&audit_net_ops);
+
+	audit_initialized = AUDIT_INITIALIZED;
+
+	kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
+	if (IS_ERR(kauditd_task)) {
+		int err = PTR_ERR(kauditd_task);
+		panic("audit: failed to start the kauditd thread (%d)\n", err);
+	}
+
+	audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
+		"state=initialized audit_enabled=%u res=1",
+		 audit_enabled);
+
+	return 0;
+}
+postcore_initcall(audit_init);
+
+/*
+ * Process kernel command-line parameter at boot time.
+ * audit={0|off} or audit={1|on}.
+ */
+static int __init audit_enable(char *str)
+{
+	if (!strcasecmp(str, "off") || !strcmp(str, "0"))
+		audit_default = AUDIT_OFF;
+	else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
+		audit_default = AUDIT_ON;
+	else {
+		pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
+		audit_default = AUDIT_ON;
+	}
+
+	if (audit_default == AUDIT_OFF)
+		audit_initialized = AUDIT_DISABLED;
+	if (audit_set_enabled(audit_default))
+		pr_err("audit: error setting audit state (%d)\n",
+		       audit_default);
+
+	pr_info("%s\n", audit_default ?
+		"enabled (after initialization)" : "disabled (until reboot)");
+
+	return 1;
+}
+__setup("audit=", audit_enable);
+
+/* Process kernel command-line parameter at boot time.
+ * audit_backlog_limit=<n> */
+static int __init audit_backlog_limit_set(char *str)
+{
+	u32 audit_backlog_limit_arg;
+
+	pr_info("audit_backlog_limit: ");
+	if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
+		pr_cont("using default of %u, unable to parse %s\n",
+			audit_backlog_limit, str);
+		return 1;
+	}
+
+	audit_backlog_limit = audit_backlog_limit_arg;
+	pr_cont("%d\n", audit_backlog_limit);
+
+	return 1;
+}
+__setup("audit_backlog_limit=", audit_backlog_limit_set);
+
+static void audit_buffer_free(struct audit_buffer *ab)
+{
+	if (!ab)
+		return;
+
+	kfree_skb(ab->skb);
+	kmem_cache_free(audit_buffer_cache, ab);
+}
+
+static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
+					       gfp_t gfp_mask, int type)
+{
+	struct audit_buffer *ab;
+
+	ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
+	if (!ab)
+		return NULL;
+
+	ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
+	if (!ab->skb)
+		goto err;
+	if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
+		goto err;
+
+	ab->ctx = ctx;
+	ab->gfp_mask = gfp_mask;
+
+	return ab;
+
+err:
+	audit_buffer_free(ab);
+	return NULL;
+}
+
+/**
+ * audit_serial - compute a serial number for the audit record
+ *
+ * Compute a serial number for the audit record.  Audit records are
+ * written to user-space as soon as they are generated, so a complete
+ * audit record may be written in several pieces.  The timestamp of the
+ * record and this serial number are used by the user-space tools to
+ * determine which pieces belong to the same audit record.  The
+ * (timestamp,serial) tuple is unique for each syscall and is live from
+ * syscall entry to syscall exit.
+ *
+ * NOTE: Another possibility is to store the formatted records off the
+ * audit context (for those records that have a context), and emit them
+ * all at syscall exit.  However, this could delay the reporting of
+ * significant errors until syscall exit (or never, if the system
+ * halts).
+ */
+unsigned int audit_serial(void)
+{
+	static atomic_t serial = ATOMIC_INIT(0);
+
+	return atomic_inc_return(&serial);
+}
+
+static inline void audit_get_stamp(struct audit_context *ctx,
+				   struct timespec64 *t, unsigned int *serial)
+{
+	if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
+		ktime_get_coarse_real_ts64(t);
+		*serial = audit_serial();
+	}
+}
+
+/**
+ * audit_log_start - obtain an audit buffer
+ * @ctx: audit_context (may be NULL)
+ * @gfp_mask: type of allocation
+ * @type: audit message type
+ *
+ * Returns audit_buffer pointer on success or NULL on error.
+ *
+ * Obtain an audit buffer.  This routine does locking to obtain the
+ * audit buffer, but then no locking is required for calls to
+ * audit_log_*format.  If the task (ctx) is a task that is currently in a
+ * syscall, then the syscall is marked as auditable and an audit record
+ * will be written at syscall exit.  If there is no associated task, then
+ * task context (ctx) should be NULL.
+ */
+struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
+				     int type)
+{
+	struct audit_buffer *ab;
+	struct timespec64 t;
+	unsigned int serial;
+
+	if (audit_initialized != AUDIT_INITIALIZED)
+		return NULL;
+
+	if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
+		return NULL;
+
+	/* NOTE: don't ever fail/sleep on these two conditions:
+	 * 1. auditd generated record - since we need auditd to drain the
+	 *    queue; also, when we are checking for auditd, compare PIDs using
+	 *    task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
+	 *    using a PID anchored in the caller's namespace
+	 * 2. generator holding the audit_cmd_mutex - we don't want to block
+	 *    while holding the mutex, although we do penalize the sender
+	 *    later in audit_receive() when it is safe to block
+	 */
+	if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
+		long stime = audit_backlog_wait_time;
+
+		while (audit_backlog_limit &&
+		       (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
+			/* wake kauditd to try and flush the queue */
+			wake_up_interruptible(&kauditd_wait);
+
+			/* sleep if we are allowed and we haven't exhausted our
+			 * backlog wait limit */
+			if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
+				long rtime = stime;
+
+				DECLARE_WAITQUEUE(wait, current);
+
+				add_wait_queue_exclusive(&audit_backlog_wait,
+							 &wait);
+				set_current_state(TASK_UNINTERRUPTIBLE);
+				stime = schedule_timeout(rtime);
+				atomic_add(rtime - stime, &audit_backlog_wait_time_actual);
+				remove_wait_queue(&audit_backlog_wait, &wait);
+			} else {
+				if (audit_rate_check() && printk_ratelimit())
+					pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
+						skb_queue_len(&audit_queue),
+						audit_backlog_limit);
+				audit_log_lost("backlog limit exceeded");
+				return NULL;
+			}
+		}
+	}
+
+	ab = audit_buffer_alloc(ctx, gfp_mask, type);
+	if (!ab) {
+		audit_log_lost("out of memory in audit_log_start");
+		return NULL;
+	}
+
+	audit_get_stamp(ab->ctx, &t, &serial);
+	/* cancel dummy context to enable supporting records */
+	if (ctx)
+		ctx->dummy = 0;
+	audit_log_format(ab, "audit(%llu.%03lu:%u): ",
+			 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
+
+	return ab;
+}
+
+/**
+ * audit_expand - expand skb in the audit buffer
+ * @ab: audit_buffer
+ * @extra: space to add at tail of the skb
+ *
+ * Returns 0 (no space) on failed expansion, or available space if
+ * successful.
+ */
+static inline int audit_expand(struct audit_buffer *ab, int extra)
+{
+	struct sk_buff *skb = ab->skb;
+	int oldtail = skb_tailroom(skb);
+	int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
+	int newtail = skb_tailroom(skb);
+
+	if (ret < 0) {
+		audit_log_lost("out of memory in audit_expand");
+		return 0;
+	}
+
+	skb->truesize += newtail - oldtail;
+	return newtail;
+}
+
+/*
+ * Format an audit message into the audit buffer.  If there isn't enough
+ * room in the audit buffer, more room will be allocated and vsnprint
+ * will be called a second time.  Currently, we assume that a printk
+ * can't format message larger than 1024 bytes, so we don't either.
+ */
+static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
+			      va_list args)
+{
+	int len, avail;
+	struct sk_buff *skb;
+	va_list args2;
+
+	if (!ab)
+		return;
+
+	BUG_ON(!ab->skb);
+	skb = ab->skb;
+	avail = skb_tailroom(skb);
+	if (avail == 0) {
+		avail = audit_expand(ab, AUDIT_BUFSIZ);
+		if (!avail)
+			goto out;
+	}
+	va_copy(args2, args);
+	len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
+	if (len >= avail) {
+		/* The printk buffer is 1024 bytes long, so if we get
+		 * here and AUDIT_BUFSIZ is at least 1024, then we can
+		 * log everything that printk could have logged. */
+		avail = audit_expand(ab,
+			max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
+		if (!avail)
+			goto out_va_end;
+		len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
+	}
+	if (len > 0)
+		skb_put(skb, len);
+out_va_end:
+	va_end(args2);
+out:
+	return;
+}
+
+/**
+ * audit_log_format - format a message into the audit buffer.
+ * @ab: audit_buffer
+ * @fmt: format string
+ * @...: optional parameters matching @fmt string
+ *
+ * All the work is done in audit_log_vformat.
+ */
+void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
+{
+	va_list args;
+
+	if (!ab)
+		return;
+	va_start(args, fmt);
+	audit_log_vformat(ab, fmt, args);
+	va_end(args);
+}
+
+/**
+ * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
+ * @ab: the audit_buffer
+ * @buf: buffer to convert to hex
+ * @len: length of @buf to be converted
+ *
+ * No return value; failure to expand is silently ignored.
+ *
+ * This function will take the passed buf and convert it into a string of
+ * ascii hex digits. The new string is placed onto the skb.
+ */
+void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
+		size_t len)
+{
+	int i, avail, new_len;
+	unsigned char *ptr;
+	struct sk_buff *skb;
+
+	if (!ab)
+		return;
+
+	BUG_ON(!ab->skb);
+	skb = ab->skb;
+	avail = skb_tailroom(skb);
+	new_len = len<<1;
+	if (new_len >= avail) {
+		/* Round the buffer request up to the next multiple */
+		new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
+		avail = audit_expand(ab, new_len);
+		if (!avail)
+			return;
+	}
+
+	ptr = skb_tail_pointer(skb);
+	for (i = 0; i < len; i++)
+		ptr = hex_byte_pack_upper(ptr, buf[i]);
+	*ptr = 0;
+	skb_put(skb, len << 1); /* new string is twice the old string */
+}
+
+/*
+ * Format a string of no more than slen characters into the audit buffer,
+ * enclosed in quote marks.
+ */
+void audit_log_n_string(struct audit_buffer *ab, const char *string,
+			size_t slen)
+{
+	int avail, new_len;
+	unsigned char *ptr;
+	struct sk_buff *skb;
+
+	if (!ab)
+		return;
+
+	BUG_ON(!ab->skb);
+	skb = ab->skb;
+	avail = skb_tailroom(skb);
+	new_len = slen + 3;	/* enclosing quotes + null terminator */
+	if (new_len > avail) {
+		avail = audit_expand(ab, new_len);
+		if (!avail)
+			return;
+	}
+	ptr = skb_tail_pointer(skb);
+	*ptr++ = '"';
+	memcpy(ptr, string, slen);
+	ptr += slen;
+	*ptr++ = '"';
+	*ptr = 0;
+	skb_put(skb, slen + 2);	/* don't include null terminator */
+}
+
+/**
+ * audit_string_contains_control - does a string need to be logged in hex
+ * @string: string to be checked
+ * @len: max length of the string to check
+ */
+bool audit_string_contains_control(const char *string, size_t len)
+{
+	const unsigned char *p;
+	for (p = string; p < (const unsigned char *)string + len; p++) {
+		if (*p == '"' || *p < 0x21 || *p > 0x7e)
+			return true;
+	}
+	return false;
+}
+
+/**
+ * audit_log_n_untrustedstring - log a string that may contain random characters
+ * @ab: audit_buffer
+ * @len: length of string (not including trailing null)
+ * @string: string to be logged
+ *
+ * This code will escape a string that is passed to it if the string
+ * contains a control character, unprintable character, double quote mark,
+ * or a space. Unescaped strings will start and end with a double quote mark.
+ * Strings that are escaped are printed in hex (2 digits per char).
+ *
+ * The caller specifies the number of characters in the string to log, which may
+ * or may not be the entire string.
+ */
+void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
+				 size_t len)
+{
+	if (audit_string_contains_control(string, len))
+		audit_log_n_hex(ab, string, len);
+	else
+		audit_log_n_string(ab, string, len);
+}
+
+/**
+ * audit_log_untrustedstring - log a string that may contain random characters
+ * @ab: audit_buffer
+ * @string: string to be logged
+ *
+ * Same as audit_log_n_untrustedstring(), except that strlen is used to
+ * determine string length.
+ */
+void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
+{
+	audit_log_n_untrustedstring(ab, string, strlen(string));
+}
+
+/* This is a helper-function to print the escaped d_path */
+void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
+		      const struct path *path)
+{
+	char *p, *pathname;
+
+	if (prefix)
+		audit_log_format(ab, "%s", prefix);
+
+	/* We will allow 11 spaces for ' (deleted)' to be appended */
+	pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
+	if (!pathname) {
+		audit_log_format(ab, "\"<no_memory>\"");
+		return;
+	}
+	p = d_path(path, pathname, PATH_MAX+11);
+	if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
+		/* FIXME: can we save some information here? */
+		audit_log_format(ab, "\"<too_long>\"");
+	} else
+		audit_log_untrustedstring(ab, p);
+	kfree(pathname);
+}
+
+void audit_log_session_info(struct audit_buffer *ab)
+{
+	unsigned int sessionid = audit_get_sessionid(current);
+	uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
+
+	audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
+}
+
+void audit_log_key(struct audit_buffer *ab, char *key)
+{
+	audit_log_format(ab, " key=");
+	if (key)
+		audit_log_untrustedstring(ab, key);
+	else
+		audit_log_format(ab, "(null)");
+}
+
+int audit_log_task_context(struct audit_buffer *ab)
+{
+	char *ctx = NULL;
+	unsigned len;
+	int error;
+	u32 sid;
+
+	security_current_getsecid_subj(&sid);
+	if (!sid)
+		return 0;
+
+	error = security_secid_to_secctx(sid, &ctx, &len);
+	if (error) {
+		if (error != -EINVAL)
+			goto error_path;
+		return 0;
+	}
+
+	audit_log_format(ab, " subj=%s", ctx);
+	security_release_secctx(ctx, len);
+	return 0;
+
+error_path:
+	audit_panic("error in audit_log_task_context");
+	return error;
+}
+EXPORT_SYMBOL(audit_log_task_context);
+
+void audit_log_d_path_exe(struct audit_buffer *ab,
+			  struct mm_struct *mm)
+{
+	struct file *exe_file;
+
+	if (!mm)
+		goto out_null;
+
+	exe_file = get_mm_exe_file(mm);
+	if (!exe_file)
+		goto out_null;
+
+	audit_log_d_path(ab, " exe=", &exe_file->f_path);
+	fput(exe_file);
+	return;
+out_null:
+	audit_log_format(ab, " exe=(null)");
+}
+
+struct tty_struct *audit_get_tty(void)
+{
+	struct tty_struct *tty = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&current->sighand->siglock, flags);
+	if (current->signal)
+		tty = tty_kref_get(current->signal->tty);
+	spin_unlock_irqrestore(&current->sighand->siglock, flags);
+	return tty;
+}
+
+void audit_put_tty(struct tty_struct *tty)
+{
+	tty_kref_put(tty);
+}
+
+void audit_log_task_info(struct audit_buffer *ab)
+{
+	const struct cred *cred;
+	char comm[sizeof(current->comm)];
+	struct tty_struct *tty;
+
+	if (!ab)
+		return;
+
+	cred = current_cred();
+	tty = audit_get_tty();
+	audit_log_format(ab,
+			 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
+			 " euid=%u suid=%u fsuid=%u"
+			 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
+			 task_ppid_nr(current),
+			 task_tgid_nr(current),
+			 from_kuid(&init_user_ns, audit_get_loginuid(current)),
+			 from_kuid(&init_user_ns, cred->uid),
+			 from_kgid(&init_user_ns, cred->gid),
+			 from_kuid(&init_user_ns, cred->euid),
+			 from_kuid(&init_user_ns, cred->suid),
+			 from_kuid(&init_user_ns, cred->fsuid),
+			 from_kgid(&init_user_ns, cred->egid),
+			 from_kgid(&init_user_ns, cred->sgid),
+			 from_kgid(&init_user_ns, cred->fsgid),
+			 tty ? tty_name(tty) : "(none)",
+			 audit_get_sessionid(current));
+	audit_put_tty(tty);
+	audit_log_format(ab, " comm=");
+	audit_log_untrustedstring(ab, get_task_comm(comm, current));
+	audit_log_d_path_exe(ab, current->mm);
+	audit_log_task_context(ab);
+}
+EXPORT_SYMBOL(audit_log_task_info);
+
+/**
+ * audit_log_path_denied - report a path restriction denial
+ * @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
+ * @operation: specific operation name
+ */
+void audit_log_path_denied(int type, const char *operation)
+{
+	struct audit_buffer *ab;
+
+	if (!audit_enabled || audit_dummy_context())
+		return;
+
+	/* Generate log with subject, operation, outcome. */
+	ab = audit_log_start(audit_context(), GFP_KERNEL, type);
+	if (!ab)
+		return;
+	audit_log_format(ab, "op=%s", operation);
+	audit_log_task_info(ab);
+	audit_log_format(ab, " res=0");
+	audit_log_end(ab);
+}
+
+/* global counter which is incremented every time something logs in */
+static atomic_t session_id = ATOMIC_INIT(0);
+
+static int audit_set_loginuid_perm(kuid_t loginuid)
+{
+	/* if we are unset, we don't need privs */
+	if (!audit_loginuid_set(current))
+		return 0;
+	/* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
+	if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
+		return -EPERM;
+	/* it is set, you need permission */
+	if (!capable(CAP_AUDIT_CONTROL))
+		return -EPERM;
+	/* reject if this is not an unset and we don't allow that */
+	if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
+				 && uid_valid(loginuid))
+		return -EPERM;
+	return 0;
+}
+
+static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
+				   unsigned int oldsessionid,
+				   unsigned int sessionid, int rc)
+{
+	struct audit_buffer *ab;
+	uid_t uid, oldloginuid, loginuid;
+	struct tty_struct *tty;
+
+	if (!audit_enabled)
+		return;
+
+	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
+	if (!ab)
+		return;
+
+	uid = from_kuid(&init_user_ns, task_uid(current));
+	oldloginuid = from_kuid(&init_user_ns, koldloginuid);
+	loginuid = from_kuid(&init_user_ns, kloginuid);
+	tty = audit_get_tty();
+
+	audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
+	audit_log_task_context(ab);
+	audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
+			 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
+			 oldsessionid, sessionid, !rc);
+	audit_put_tty(tty);
+	audit_log_end(ab);
+}
+
+/**
+ * audit_set_loginuid - set current task's loginuid
+ * @loginuid: loginuid value
+ *
+ * Returns 0.
+ *
+ * Called (set) from fs/proc/base.c::proc_loginuid_write().
+ */
+int audit_set_loginuid(kuid_t loginuid)
+{
+	unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
+	kuid_t oldloginuid;
+	int rc;
+
+	oldloginuid = audit_get_loginuid(current);
+	oldsessionid = audit_get_sessionid(current);
+
+	rc = audit_set_loginuid_perm(loginuid);
+	if (rc)
+		goto out;
+
+	/* are we setting or clearing? */
+	if (uid_valid(loginuid)) {
+		sessionid = (unsigned int)atomic_inc_return(&session_id);
+		if (unlikely(sessionid == AUDIT_SID_UNSET))
+			sessionid = (unsigned int)atomic_inc_return(&session_id);
+	}
+
+	current->sessionid = sessionid;
+	current->loginuid = loginuid;
+out:
+	audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
+	return rc;
+}
+
+/**
+ * audit_signal_info - record signal info for shutting down audit subsystem
+ * @sig: signal value
+ * @t: task being signaled
+ *
+ * If the audit subsystem is being terminated, record the task (pid)
+ * and uid that is doing that.
+ */
+int audit_signal_info(int sig, struct task_struct *t)
+{
+	kuid_t uid = current_uid(), auid;
+
+	if (auditd_test_task(t) &&
+	    (sig == SIGTERM || sig == SIGHUP ||
+	     sig == SIGUSR1 || sig == SIGUSR2)) {
+		audit_sig_pid = task_tgid_nr(current);
+		auid = audit_get_loginuid(current);
+		if (uid_valid(auid))
+			audit_sig_uid = auid;
+		else
+			audit_sig_uid = uid;
+		security_current_getsecid_subj(&audit_sig_sid);
+	}
+
+	return audit_signal_info_syscall(t);
+}
+
+/**
+ * audit_log_end - end one audit record
+ * @ab: the audit_buffer
+ *
+ * We can not do a netlink send inside an irq context because it blocks (last
+ * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
+ * queue and a kthread is scheduled to remove them from the queue outside the
+ * irq context.  May be called in any context.
+ */
+void audit_log_end(struct audit_buffer *ab)
+{
+	struct sk_buff *skb;
+	struct nlmsghdr *nlh;
+
+	if (!ab)
+		return;
+
+	if (audit_rate_check()) {
+		skb = ab->skb;
+		ab->skb = NULL;
+
+		/* setup the netlink header, see the comments in
+		 * kauditd_send_multicast_skb() for length quirks */
+		nlh = nlmsg_hdr(skb);
+		nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
+
+		/* queue the netlink packet and poke the kauditd thread */
+		skb_queue_tail(&audit_queue, skb);
+		wake_up_interruptible(&kauditd_wait);
+	} else
+		audit_log_lost("rate limit exceeded");
+
+	audit_buffer_free(ab);
+}
+
+/**
+ * audit_log - Log an audit record
+ * @ctx: audit context
+ * @gfp_mask: type of allocation
+ * @type: audit message type
+ * @fmt: format string to use
+ * @...: variable parameters matching the format string
+ *
+ * This is a convenience function that calls audit_log_start,
+ * audit_log_vformat, and audit_log_end.  It may be called
+ * in any context.
+ */
+void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
+	       const char *fmt, ...)
+{
+	struct audit_buffer *ab;
+	va_list args;
+
+	ab = audit_log_start(ctx, gfp_mask, type);
+	if (ab) {
+		va_start(args, fmt);
+		audit_log_vformat(ab, fmt, args);
+		va_end(args);
+		audit_log_end(ab);
+	}
+}
+
+EXPORT_SYMBOL(audit_log_start);
+EXPORT_SYMBOL(audit_log_end);
+EXPORT_SYMBOL(audit_log_format);
+EXPORT_SYMBOL(audit_log);
diff --git a/kernel/audit.h b/kernel/audit.h
new file mode 100644
index 000000000..c57b008b9
--- /dev/null
+++ b/kernel/audit.h
@@ -0,0 +1,347 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* audit -- definition of audit_context structure and supporting types
+ *
+ * Copyright 2003-2004 Red Hat, Inc.
+ * Copyright 2005 Hewlett-Packard Development Company, L.P.
+ * Copyright 2005 IBM Corporation
+ */
+
+#ifndef _KERNEL_AUDIT_H_
+#define _KERNEL_AUDIT_H_
+
+#include <linux/fs.h>
+#include <linux/audit.h>
+#include <linux/skbuff.h>
+#include <uapi/linux/mqueue.h>
+#include <linux/tty.h>
+#include <uapi/linux/openat2.h> // struct open_how
+
+/* AUDIT_NAMES is the number of slots we reserve in the audit_context
+ * for saving names from getname().  If we get more names we will allocate
+ * a name dynamically and also add those to the list anchored by names_list. */
+#define AUDIT_NAMES	5
+
+/* At task start time, the audit_state is set in the audit_context using
+   a per-task filter.  At syscall entry, the audit_state is augmented by
+   the syscall filter. */
+enum audit_state {
+	AUDIT_STATE_DISABLED,	/* Do not create per-task audit_context.
+				 * No syscall-specific audit records can
+				 * be generated. */
+	AUDIT_STATE_BUILD,	/* Create the per-task audit_context,
+				 * and fill it in at syscall
+				 * entry time.  This makes a full
+				 * syscall record available if some
+				 * other part of the kernel decides it
+				 * should be recorded. */
+	AUDIT_STATE_RECORD	/* Create the per-task audit_context,
+				 * always fill it in at syscall entry
+				 * time, and always write out the audit
+				 * record at syscall exit time.  */
+};
+
+/* Rule lists */
+struct audit_watch;
+struct audit_fsnotify_mark;
+struct audit_tree;
+struct audit_chunk;
+
+struct audit_entry {
+	struct list_head	list;
+	struct rcu_head		rcu;
+	struct audit_krule	rule;
+};
+
+struct audit_cap_data {
+	kernel_cap_t		permitted;
+	kernel_cap_t		inheritable;
+	union {
+		unsigned int	fE;		/* effective bit of file cap */
+		kernel_cap_t	effective;	/* effective set of process */
+	};
+	kernel_cap_t		ambient;
+	kuid_t			rootid;
+};
+
+/* When fs/namei.c:getname() is called, we store the pointer in name and bump
+ * the refcnt in the associated filename struct.
+ *
+ * Further, in fs/namei.c:path_lookup() we store the inode and device.
+ */
+struct audit_names {
+	struct list_head	list;		/* audit_context->names_list */
+
+	struct filename		*name;
+	int			name_len;	/* number of chars to log */
+	bool			hidden;		/* don't log this record */
+
+	unsigned long		ino;
+	dev_t			dev;
+	umode_t			mode;
+	kuid_t			uid;
+	kgid_t			gid;
+	dev_t			rdev;
+	u32			osid;
+	struct audit_cap_data	fcap;
+	unsigned int		fcap_ver;
+	unsigned char		type;		/* record type */
+	/*
+	 * This was an allocated audit_names and not from the array of
+	 * names allocated in the task audit context.  Thus this name
+	 * should be freed on syscall exit.
+	 */
+	bool			should_free;
+};
+
+struct audit_proctitle {
+	int	len;	/* length of the cmdline field. */
+	char	*value;	/* the cmdline field */
+};
+
+/* The per-task audit context. */
+struct audit_context {
+	int		    dummy;	/* must be the first element */
+	enum {
+		AUDIT_CTX_UNUSED,	/* audit_context is currently unused */
+		AUDIT_CTX_SYSCALL,	/* in use by syscall */
+		AUDIT_CTX_URING,	/* in use by io_uring */
+	} context;
+	enum audit_state    state, current_state;
+	unsigned int	    serial;     /* serial number for record */
+	int		    major;      /* syscall number */
+	int		    uring_op;   /* uring operation */
+	struct timespec64   ctime;      /* time of syscall entry */
+	unsigned long	    argv[4];    /* syscall arguments */
+	long		    return_code;/* syscall return code */
+	u64		    prio;
+	int		    return_valid; /* return code is valid */
+	/*
+	 * The names_list is the list of all audit_names collected during this
+	 * syscall.  The first AUDIT_NAMES entries in the names_list will
+	 * actually be from the preallocated_names array for performance
+	 * reasons.  Except during allocation they should never be referenced
+	 * through the preallocated_names array and should only be found/used
+	 * by running the names_list.
+	 */
+	struct audit_names  preallocated_names[AUDIT_NAMES];
+	int		    name_count; /* total records in names_list */
+	struct list_head    names_list;	/* struct audit_names->list anchor */
+	char		    *filterkey;	/* key for rule that triggered record */
+	struct path	    pwd;
+	struct audit_aux_data *aux;
+	struct audit_aux_data *aux_pids;
+	struct sockaddr_storage *sockaddr;
+	size_t sockaddr_len;
+				/* Save things to print about task_struct */
+	pid_t		    ppid;
+	kuid_t		    uid, euid, suid, fsuid;
+	kgid_t		    gid, egid, sgid, fsgid;
+	unsigned long	    personality;
+	int		    arch;
+
+	pid_t		    target_pid;
+	kuid_t		    target_auid;
+	kuid_t		    target_uid;
+	unsigned int	    target_sessionid;
+	u32		    target_sid;
+	char		    target_comm[TASK_COMM_LEN];
+
+	struct audit_tree_refs *trees, *first_trees;
+	struct list_head killed_trees;
+	int tree_count;
+
+	int type;
+	union {
+		struct {
+			int nargs;
+			long args[6];
+		} socketcall;
+		struct {
+			kuid_t			uid;
+			kgid_t			gid;
+			umode_t			mode;
+			u32			osid;
+			int			has_perm;
+			uid_t			perm_uid;
+			gid_t			perm_gid;
+			umode_t			perm_mode;
+			unsigned long		qbytes;
+		} ipc;
+		struct {
+			mqd_t			mqdes;
+			struct mq_attr		mqstat;
+		} mq_getsetattr;
+		struct {
+			mqd_t			mqdes;
+			int			sigev_signo;
+		} mq_notify;
+		struct {
+			mqd_t			mqdes;
+			size_t			msg_len;
+			unsigned int		msg_prio;
+			struct timespec64	abs_timeout;
+		} mq_sendrecv;
+		struct {
+			int			oflag;
+			umode_t			mode;
+			struct mq_attr		attr;
+		} mq_open;
+		struct {
+			pid_t			pid;
+			struct audit_cap_data	cap;
+		} capset;
+		struct {
+			int			fd;
+			int			flags;
+		} mmap;
+		struct open_how openat2;
+		struct {
+			int			argc;
+		} execve;
+		struct {
+			char			*name;
+		} module;
+		struct {
+			struct audit_ntp_data	ntp_data;
+			struct timespec64	tk_injoffset;
+		} time;
+	};
+	int fds[2];
+	struct audit_proctitle proctitle;
+};
+
+extern bool audit_ever_enabled;
+
+extern void audit_log_session_info(struct audit_buffer *ab);
+
+extern int auditd_test_task(struct task_struct *task);
+
+#define AUDIT_INODE_BUCKETS	32
+extern struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
+
+static inline int audit_hash_ino(u32 ino)
+{
+	return (ino & (AUDIT_INODE_BUCKETS-1));
+}
+
+/* Indicates that audit should log the full pathname. */
+#define AUDIT_NAME_FULL -1
+
+extern int audit_match_class(int class, unsigned syscall);
+extern int audit_comparator(const u32 left, const u32 op, const u32 right);
+extern int audit_uid_comparator(kuid_t left, u32 op, kuid_t right);
+extern int audit_gid_comparator(kgid_t left, u32 op, kgid_t right);
+extern int parent_len(const char *path);
+extern int audit_compare_dname_path(const struct qstr *dname, const char *path, int plen);
+extern struct sk_buff *audit_make_reply(int seq, int type, int done, int multi,
+					const void *payload, int size);
+extern void		    audit_panic(const char *message);
+
+struct audit_netlink_list {
+	__u32 portid;
+	struct net *net;
+	struct sk_buff_head q;
+};
+
+int audit_send_list_thread(void *_dest);
+
+extern struct mutex audit_filter_mutex;
+extern int audit_del_rule(struct audit_entry *entry);
+extern void audit_free_rule_rcu(struct rcu_head *head);
+extern struct list_head audit_filter_list[];
+
+extern struct audit_entry *audit_dupe_rule(struct audit_krule *old);
+
+extern void audit_log_d_path_exe(struct audit_buffer *ab,
+				 struct mm_struct *mm);
+
+extern struct tty_struct *audit_get_tty(void);
+extern void audit_put_tty(struct tty_struct *tty);
+
+/* audit watch/mark/tree functions */
+#ifdef CONFIG_AUDITSYSCALL
+extern unsigned int audit_serial(void);
+extern int auditsc_get_stamp(struct audit_context *ctx,
+			      struct timespec64 *t, unsigned int *serial);
+
+extern void audit_put_watch(struct audit_watch *watch);
+extern void audit_get_watch(struct audit_watch *watch);
+extern int audit_to_watch(struct audit_krule *krule, char *path, int len,
+			  u32 op);
+extern int audit_add_watch(struct audit_krule *krule, struct list_head **list);
+extern void audit_remove_watch_rule(struct audit_krule *krule);
+extern char *audit_watch_path(struct audit_watch *watch);
+extern int audit_watch_compare(struct audit_watch *watch, unsigned long ino,
+			       dev_t dev);
+
+extern struct audit_fsnotify_mark *audit_alloc_mark(struct audit_krule *krule,
+						    char *pathname, int len);
+extern char *audit_mark_path(struct audit_fsnotify_mark *mark);
+extern void audit_remove_mark(struct audit_fsnotify_mark *audit_mark);
+extern void audit_remove_mark_rule(struct audit_krule *krule);
+extern int audit_mark_compare(struct audit_fsnotify_mark *mark,
+			      unsigned long ino, dev_t dev);
+extern int audit_dupe_exe(struct audit_krule *new, struct audit_krule *old);
+extern int audit_exe_compare(struct task_struct *tsk,
+			     struct audit_fsnotify_mark *mark);
+
+extern struct audit_chunk *audit_tree_lookup(const struct inode *inode);
+extern void audit_put_chunk(struct audit_chunk *chunk);
+extern bool audit_tree_match(struct audit_chunk *chunk,
+			     struct audit_tree *tree);
+extern int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op);
+extern int audit_add_tree_rule(struct audit_krule *rule);
+extern int audit_remove_tree_rule(struct audit_krule *rule);
+extern void audit_trim_trees(void);
+extern int audit_tag_tree(char *old, char *new);
+extern const char *audit_tree_path(struct audit_tree *tree);
+extern void audit_put_tree(struct audit_tree *tree);
+extern void audit_kill_trees(struct audit_context *context);
+
+extern int audit_signal_info_syscall(struct task_struct *t);
+extern void audit_filter_inodes(struct task_struct *tsk,
+				struct audit_context *ctx);
+extern struct list_head *audit_killed_trees(void);
+#else /* CONFIG_AUDITSYSCALL */
+#define auditsc_get_stamp(c, t, s) 0
+#define audit_put_watch(w) do { } while (0)
+#define audit_get_watch(w) do { } while (0)
+#define audit_to_watch(k, p, l, o) (-EINVAL)
+#define audit_add_watch(k, l) (-EINVAL)
+#define audit_remove_watch_rule(k) BUG()
+#define audit_watch_path(w) ""
+#define audit_watch_compare(w, i, d) 0
+
+#define audit_alloc_mark(k, p, l) (ERR_PTR(-EINVAL))
+#define audit_mark_path(m) ""
+#define audit_remove_mark(m) do { } while (0)
+#define audit_remove_mark_rule(k) do { } while (0)
+#define audit_mark_compare(m, i, d) 0
+#define audit_exe_compare(t, m) (-EINVAL)
+#define audit_dupe_exe(n, o) (-EINVAL)
+
+#define audit_remove_tree_rule(rule) BUG()
+#define audit_add_tree_rule(rule) -EINVAL
+#define audit_make_tree(rule, str, op) -EINVAL
+#define audit_trim_trees() do { } while (0)
+#define audit_put_tree(tree) do { } while (0)
+#define audit_tag_tree(old, new) -EINVAL
+#define audit_tree_path(rule) ""	/* never called */
+#define audit_kill_trees(context) BUG()
+
+static inline int audit_signal_info_syscall(struct task_struct *t)
+{
+	return 0;
+}
+
+#define audit_filter_inodes(t, c) AUDIT_STATE_DISABLED
+#endif /* CONFIG_AUDITSYSCALL */
+
+extern char *audit_unpack_string(void **bufp, size_t *remain, size_t len);
+
+extern int audit_filter(int msgtype, unsigned int listtype);
+
+extern void audit_ctl_lock(void);
+extern void audit_ctl_unlock(void);
+
+#endif
diff --git a/kernel/audit_fsnotify.c b/kernel/audit_fsnotify.c
new file mode 100644
index 000000000..c565fbf66
--- /dev/null
+++ b/kernel/audit_fsnotify.c
@@ -0,0 +1,193 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* audit_fsnotify.c -- tracking inodes
+ *
+ * Copyright 2003-2009,2014-2015 Red Hat, Inc.
+ * Copyright 2005 Hewlett-Packard Development Company, L.P.
+ * Copyright 2005 IBM Corporation
+ */
+
+#include <linux/kernel.h>
+#include <linux/audit.h>
+#include <linux/kthread.h>
+#include <linux/mutex.h>
+#include <linux/fs.h>
+#include <linux/fsnotify_backend.h>
+#include <linux/namei.h>
+#include <linux/netlink.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include "audit.h"
+
+/*
+ * this mark lives on the parent directory of the inode in question.
+ * but dev, ino, and path are about the child
+ */
+struct audit_fsnotify_mark {
+	dev_t dev;		/* associated superblock device */
+	unsigned long ino;	/* associated inode number */
+	char *path;		/* insertion path */
+	struct fsnotify_mark mark; /* fsnotify mark on the inode */
+	struct audit_krule *rule;
+};
+
+/* fsnotify handle. */
+static struct fsnotify_group *audit_fsnotify_group;
+
+/* fsnotify events we care about. */
+#define AUDIT_FS_EVENTS (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
+			 FS_MOVE_SELF)
+
+static void audit_fsnotify_mark_free(struct audit_fsnotify_mark *audit_mark)
+{
+	kfree(audit_mark->path);
+	kfree(audit_mark);
+}
+
+static void audit_fsnotify_free_mark(struct fsnotify_mark *mark)
+{
+	struct audit_fsnotify_mark *audit_mark;
+
+	audit_mark = container_of(mark, struct audit_fsnotify_mark, mark);
+	audit_fsnotify_mark_free(audit_mark);
+}
+
+char *audit_mark_path(struct audit_fsnotify_mark *mark)
+{
+	return mark->path;
+}
+
+int audit_mark_compare(struct audit_fsnotify_mark *mark, unsigned long ino, dev_t dev)
+{
+	if (mark->ino == AUDIT_INO_UNSET)
+		return 0;
+	return (mark->ino == ino) && (mark->dev == dev);
+}
+
+static void audit_update_mark(struct audit_fsnotify_mark *audit_mark,
+			     const struct inode *inode)
+{
+	audit_mark->dev = inode ? inode->i_sb->s_dev : AUDIT_DEV_UNSET;
+	audit_mark->ino = inode ? inode->i_ino : AUDIT_INO_UNSET;
+}
+
+struct audit_fsnotify_mark *audit_alloc_mark(struct audit_krule *krule, char *pathname, int len)
+{
+	struct audit_fsnotify_mark *audit_mark;
+	struct path path;
+	struct dentry *dentry;
+	struct inode *inode;
+	int ret;
+
+	if (pathname[0] != '/' || pathname[len-1] == '/')
+		return ERR_PTR(-EINVAL);
+
+	dentry = kern_path_locked(pathname, &path);
+	if (IS_ERR(dentry))
+		return ERR_CAST(dentry); /* returning an error */
+	inode = path.dentry->d_inode;
+	inode_unlock(inode);
+
+	audit_mark = kzalloc(sizeof(*audit_mark), GFP_KERNEL);
+	if (unlikely(!audit_mark)) {
+		audit_mark = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	fsnotify_init_mark(&audit_mark->mark, audit_fsnotify_group);
+	audit_mark->mark.mask = AUDIT_FS_EVENTS;
+	audit_mark->path = pathname;
+	audit_update_mark(audit_mark, dentry->d_inode);
+	audit_mark->rule = krule;
+
+	ret = fsnotify_add_inode_mark(&audit_mark->mark, inode, 0);
+	if (ret < 0) {
+		audit_mark->path = NULL;
+		fsnotify_put_mark(&audit_mark->mark);
+		audit_mark = ERR_PTR(ret);
+	}
+out:
+	dput(dentry);
+	path_put(&path);
+	return audit_mark;
+}
+
+static void audit_mark_log_rule_change(struct audit_fsnotify_mark *audit_mark, char *op)
+{
+	struct audit_buffer *ab;
+	struct audit_krule *rule = audit_mark->rule;
+
+	if (!audit_enabled)
+		return;
+	ab = audit_log_start(audit_context(), GFP_NOFS, AUDIT_CONFIG_CHANGE);
+	if (unlikely(!ab))
+		return;
+	audit_log_session_info(ab);
+	audit_log_format(ab, " op=%s path=", op);
+	audit_log_untrustedstring(ab, audit_mark->path);
+	audit_log_key(ab, rule->filterkey);
+	audit_log_format(ab, " list=%d res=1", rule->listnr);
+	audit_log_end(ab);
+}
+
+void audit_remove_mark(struct audit_fsnotify_mark *audit_mark)
+{
+	fsnotify_destroy_mark(&audit_mark->mark, audit_fsnotify_group);
+	fsnotify_put_mark(&audit_mark->mark);
+}
+
+void audit_remove_mark_rule(struct audit_krule *krule)
+{
+	struct audit_fsnotify_mark *mark = krule->exe;
+
+	audit_remove_mark(mark);
+}
+
+static void audit_autoremove_mark_rule(struct audit_fsnotify_mark *audit_mark)
+{
+	struct audit_krule *rule = audit_mark->rule;
+	struct audit_entry *entry = container_of(rule, struct audit_entry, rule);
+
+	audit_mark_log_rule_change(audit_mark, "autoremove_rule");
+	audit_del_rule(entry);
+}
+
+/* Update mark data in audit rules based on fsnotify events. */
+static int audit_mark_handle_event(struct fsnotify_mark *inode_mark, u32 mask,
+				   struct inode *inode, struct inode *dir,
+				   const struct qstr *dname, u32 cookie)
+{
+	struct audit_fsnotify_mark *audit_mark;
+
+	audit_mark = container_of(inode_mark, struct audit_fsnotify_mark, mark);
+
+	if (WARN_ON_ONCE(inode_mark->group != audit_fsnotify_group))
+		return 0;
+
+	if (mask & (FS_CREATE|FS_MOVED_TO|FS_DELETE|FS_MOVED_FROM)) {
+		if (audit_compare_dname_path(dname, audit_mark->path, AUDIT_NAME_FULL))
+			return 0;
+		audit_update_mark(audit_mark, inode);
+	} else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF)) {
+		audit_autoremove_mark_rule(audit_mark);
+	}
+
+	return 0;
+}
+
+static const struct fsnotify_ops audit_mark_fsnotify_ops = {
+	.handle_inode_event = audit_mark_handle_event,
+	.free_mark = audit_fsnotify_free_mark,
+};
+
+static int __init audit_fsnotify_init(void)
+{
+	audit_fsnotify_group = fsnotify_alloc_group(&audit_mark_fsnotify_ops,
+						    FSNOTIFY_GROUP_DUPS);
+	if (IS_ERR(audit_fsnotify_group)) {
+		audit_fsnotify_group = NULL;
+		audit_panic("cannot create audit fsnotify group");
+	}
+	return 0;
+}
+device_initcall(audit_fsnotify_init);
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
new file mode 100644
index 000000000..e867c17d3
--- /dev/null
+++ b/kernel/audit_tree.c
@@ -0,0 +1,1086 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "audit.h"
+#include <linux/fsnotify_backend.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/kthread.h>
+#include <linux/refcount.h>
+#include <linux/slab.h>
+
+struct audit_tree;
+struct audit_chunk;
+
+struct audit_tree {
+	refcount_t count;
+	int goner;
+	struct audit_chunk *root;
+	struct list_head chunks;
+	struct list_head rules;
+	struct list_head list;
+	struct list_head same_root;
+	struct rcu_head head;
+	char pathname[];
+};
+
+struct audit_chunk {
+	struct list_head hash;
+	unsigned long key;
+	struct fsnotify_mark *mark;
+	struct list_head trees;		/* with root here */
+	int count;
+	atomic_long_t refs;
+	struct rcu_head head;
+	struct audit_node {
+		struct list_head list;
+		struct audit_tree *owner;
+		unsigned index;		/* index; upper bit indicates 'will prune' */
+	} owners[];
+};
+
+struct audit_tree_mark {
+	struct fsnotify_mark mark;
+	struct audit_chunk *chunk;
+};
+
+static LIST_HEAD(tree_list);
+static LIST_HEAD(prune_list);
+static struct task_struct *prune_thread;
+
+/*
+ * One struct chunk is attached to each inode of interest through
+ * audit_tree_mark (fsnotify mark). We replace struct chunk on tagging /
+ * untagging, the mark is stable as long as there is chunk attached. The
+ * association between mark and chunk is protected by hash_lock and
+ * audit_tree_group->mark_mutex. Thus as long as we hold
+ * audit_tree_group->mark_mutex and check that the mark is alive by
+ * FSNOTIFY_MARK_FLAG_ATTACHED flag check, we are sure the mark points to
+ * the current chunk.
+ *
+ * Rules have pointer to struct audit_tree.
+ * Rules have struct list_head rlist forming a list of rules over
+ * the same tree.
+ * References to struct chunk are collected at audit_inode{,_child}()
+ * time and used in AUDIT_TREE rule matching.
+ * These references are dropped at the same time we are calling
+ * audit_free_names(), etc.
+ *
+ * Cyclic lists galore:
+ * tree.chunks anchors chunk.owners[].list			hash_lock
+ * tree.rules anchors rule.rlist				audit_filter_mutex
+ * chunk.trees anchors tree.same_root				hash_lock
+ * chunk.hash is a hash with middle bits of watch.inode as
+ * a hash function.						RCU, hash_lock
+ *
+ * tree is refcounted; one reference for "some rules on rules_list refer to
+ * it", one for each chunk with pointer to it.
+ *
+ * chunk is refcounted by embedded .refs. Mark associated with the chunk holds
+ * one chunk reference. This reference is dropped either when a mark is going
+ * to be freed (corresponding inode goes away) or when chunk attached to the
+ * mark gets replaced. This reference must be dropped using
+ * audit_mark_put_chunk() to make sure the reference is dropped only after RCU
+ * grace period as it protects RCU readers of the hash table.
+ *
+ * node.index allows to get from node.list to containing chunk.
+ * MSB of that sucker is stolen to mark taggings that we might have to
+ * revert - several operations have very unpleasant cleanup logics and
+ * that makes a difference.  Some.
+ */
+
+static struct fsnotify_group *audit_tree_group;
+static struct kmem_cache *audit_tree_mark_cachep __read_mostly;
+
+static struct audit_tree *alloc_tree(const char *s)
+{
+	struct audit_tree *tree;
+
+	tree = kmalloc(struct_size(tree, pathname, strlen(s) + 1), GFP_KERNEL);
+	if (tree) {
+		refcount_set(&tree->count, 1);
+		tree->goner = 0;
+		INIT_LIST_HEAD(&tree->chunks);
+		INIT_LIST_HEAD(&tree->rules);
+		INIT_LIST_HEAD(&tree->list);
+		INIT_LIST_HEAD(&tree->same_root);
+		tree->root = NULL;
+		strcpy(tree->pathname, s);
+	}
+	return tree;
+}
+
+static inline void get_tree(struct audit_tree *tree)
+{
+	refcount_inc(&tree->count);
+}
+
+static inline void put_tree(struct audit_tree *tree)
+{
+	if (refcount_dec_and_test(&tree->count))
+		kfree_rcu(tree, head);
+}
+
+/* to avoid bringing the entire thing in audit.h */
+const char *audit_tree_path(struct audit_tree *tree)
+{
+	return tree->pathname;
+}
+
+static void free_chunk(struct audit_chunk *chunk)
+{
+	int i;
+
+	for (i = 0; i < chunk->count; i++) {
+		if (chunk->owners[i].owner)
+			put_tree(chunk->owners[i].owner);
+	}
+	kfree(chunk);
+}
+
+void audit_put_chunk(struct audit_chunk *chunk)
+{
+	if (atomic_long_dec_and_test(&chunk->refs))
+		free_chunk(chunk);
+}
+
+static void __put_chunk(struct rcu_head *rcu)
+{
+	struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head);
+	audit_put_chunk(chunk);
+}
+
+/*
+ * Drop reference to the chunk that was held by the mark. This is the reference
+ * that gets dropped after we've removed the chunk from the hash table and we
+ * use it to make sure chunk cannot be freed before RCU grace period expires.
+ */
+static void audit_mark_put_chunk(struct audit_chunk *chunk)
+{
+	call_rcu(&chunk->head, __put_chunk);
+}
+
+static inline struct audit_tree_mark *audit_mark(struct fsnotify_mark *mark)
+{
+	return container_of(mark, struct audit_tree_mark, mark);
+}
+
+static struct audit_chunk *mark_chunk(struct fsnotify_mark *mark)
+{
+	return audit_mark(mark)->chunk;
+}
+
+static void audit_tree_destroy_watch(struct fsnotify_mark *mark)
+{
+	kmem_cache_free(audit_tree_mark_cachep, audit_mark(mark));
+}
+
+static struct fsnotify_mark *alloc_mark(void)
+{
+	struct audit_tree_mark *amark;
+
+	amark = kmem_cache_zalloc(audit_tree_mark_cachep, GFP_KERNEL);
+	if (!amark)
+		return NULL;
+	fsnotify_init_mark(&amark->mark, audit_tree_group);
+	amark->mark.mask = FS_IN_IGNORED;
+	return &amark->mark;
+}
+
+static struct audit_chunk *alloc_chunk(int count)
+{
+	struct audit_chunk *chunk;
+	int i;
+
+	chunk = kzalloc(struct_size(chunk, owners, count), GFP_KERNEL);
+	if (!chunk)
+		return NULL;
+
+	INIT_LIST_HEAD(&chunk->hash);
+	INIT_LIST_HEAD(&chunk->trees);
+	chunk->count = count;
+	atomic_long_set(&chunk->refs, 1);
+	for (i = 0; i < count; i++) {
+		INIT_LIST_HEAD(&chunk->owners[i].list);
+		chunk->owners[i].index = i;
+	}
+	return chunk;
+}
+
+enum {HASH_SIZE = 128};
+static struct list_head chunk_hash_heads[HASH_SIZE];
+static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock);
+
+/* Function to return search key in our hash from inode. */
+static unsigned long inode_to_key(const struct inode *inode)
+{
+	/* Use address pointed to by connector->obj as the key */
+	return (unsigned long)&inode->i_fsnotify_marks;
+}
+
+static inline struct list_head *chunk_hash(unsigned long key)
+{
+	unsigned long n = key / L1_CACHE_BYTES;
+	return chunk_hash_heads + n % HASH_SIZE;
+}
+
+/* hash_lock & mark->group->mark_mutex is held by caller */
+static void insert_hash(struct audit_chunk *chunk)
+{
+	struct list_head *list;
+
+	/*
+	 * Make sure chunk is fully initialized before making it visible in the
+	 * hash. Pairs with a data dependency barrier in READ_ONCE() in
+	 * audit_tree_lookup().
+	 */
+	smp_wmb();
+	WARN_ON_ONCE(!chunk->key);
+	list = chunk_hash(chunk->key);
+	list_add_rcu(&chunk->hash, list);
+}
+
+/* called under rcu_read_lock */
+struct audit_chunk *audit_tree_lookup(const struct inode *inode)
+{
+	unsigned long key = inode_to_key(inode);
+	struct list_head *list = chunk_hash(key);
+	struct audit_chunk *p;
+
+	list_for_each_entry_rcu(p, list, hash) {
+		/*
+		 * We use a data dependency barrier in READ_ONCE() to make sure
+		 * the chunk we see is fully initialized.
+		 */
+		if (READ_ONCE(p->key) == key) {
+			atomic_long_inc(&p->refs);
+			return p;
+		}
+	}
+	return NULL;
+}
+
+bool audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree)
+{
+	int n;
+	for (n = 0; n < chunk->count; n++)
+		if (chunk->owners[n].owner == tree)
+			return true;
+	return false;
+}
+
+/* tagging and untagging inodes with trees */
+
+static struct audit_chunk *find_chunk(struct audit_node *p)
+{
+	int index = p->index & ~(1U<<31);
+	p -= index;
+	return container_of(p, struct audit_chunk, owners[0]);
+}
+
+static void replace_mark_chunk(struct fsnotify_mark *mark,
+			       struct audit_chunk *chunk)
+{
+	struct audit_chunk *old;
+
+	assert_spin_locked(&hash_lock);
+	old = mark_chunk(mark);
+	audit_mark(mark)->chunk = chunk;
+	if (chunk)
+		chunk->mark = mark;
+	if (old)
+		old->mark = NULL;
+}
+
+static void replace_chunk(struct audit_chunk *new, struct audit_chunk *old)
+{
+	struct audit_tree *owner;
+	int i, j;
+
+	new->key = old->key;
+	list_splice_init(&old->trees, &new->trees);
+	list_for_each_entry(owner, &new->trees, same_root)
+		owner->root = new;
+	for (i = j = 0; j < old->count; i++, j++) {
+		if (!old->owners[j].owner) {
+			i--;
+			continue;
+		}
+		owner = old->owners[j].owner;
+		new->owners[i].owner = owner;
+		new->owners[i].index = old->owners[j].index - j + i;
+		if (!owner) /* result of earlier fallback */
+			continue;
+		get_tree(owner);
+		list_replace_init(&old->owners[j].list, &new->owners[i].list);
+	}
+	replace_mark_chunk(old->mark, new);
+	/*
+	 * Make sure chunk is fully initialized before making it visible in the
+	 * hash. Pairs with a data dependency barrier in READ_ONCE() in
+	 * audit_tree_lookup().
+	 */
+	smp_wmb();
+	list_replace_rcu(&old->hash, &new->hash);
+}
+
+static void remove_chunk_node(struct audit_chunk *chunk, struct audit_node *p)
+{
+	struct audit_tree *owner = p->owner;
+
+	if (owner->root == chunk) {
+		list_del_init(&owner->same_root);
+		owner->root = NULL;
+	}
+	list_del_init(&p->list);
+	p->owner = NULL;
+	put_tree(owner);
+}
+
+static int chunk_count_trees(struct audit_chunk *chunk)
+{
+	int i;
+	int ret = 0;
+
+	for (i = 0; i < chunk->count; i++)
+		if (chunk->owners[i].owner)
+			ret++;
+	return ret;
+}
+
+static void untag_chunk(struct audit_chunk *chunk, struct fsnotify_mark *mark)
+{
+	struct audit_chunk *new;
+	int size;
+
+	fsnotify_group_lock(audit_tree_group);
+	/*
+	 * mark_mutex stabilizes chunk attached to the mark so we can check
+	 * whether it didn't change while we've dropped hash_lock.
+	 */
+	if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED) ||
+	    mark_chunk(mark) != chunk)
+		goto out_mutex;
+
+	size = chunk_count_trees(chunk);
+	if (!size) {
+		spin_lock(&hash_lock);
+		list_del_init(&chunk->trees);
+		list_del_rcu(&chunk->hash);
+		replace_mark_chunk(mark, NULL);
+		spin_unlock(&hash_lock);
+		fsnotify_detach_mark(mark);
+		fsnotify_group_unlock(audit_tree_group);
+		audit_mark_put_chunk(chunk);
+		fsnotify_free_mark(mark);
+		return;
+	}
+
+	new = alloc_chunk(size);
+	if (!new)
+		goto out_mutex;
+
+	spin_lock(&hash_lock);
+	/*
+	 * This has to go last when updating chunk as once replace_chunk() is
+	 * called, new RCU readers can see the new chunk.
+	 */
+	replace_chunk(new, chunk);
+	spin_unlock(&hash_lock);
+	fsnotify_group_unlock(audit_tree_group);
+	audit_mark_put_chunk(chunk);
+	return;
+
+out_mutex:
+	fsnotify_group_unlock(audit_tree_group);
+}
+
+/* Call with group->mark_mutex held, releases it */
+static int create_chunk(struct inode *inode, struct audit_tree *tree)
+{
+	struct fsnotify_mark *mark;
+	struct audit_chunk *chunk = alloc_chunk(1);
+
+	if (!chunk) {
+		fsnotify_group_unlock(audit_tree_group);
+		return -ENOMEM;
+	}
+
+	mark = alloc_mark();
+	if (!mark) {
+		fsnotify_group_unlock(audit_tree_group);
+		kfree(chunk);
+		return -ENOMEM;
+	}
+
+	if (fsnotify_add_inode_mark_locked(mark, inode, 0)) {
+		fsnotify_group_unlock(audit_tree_group);
+		fsnotify_put_mark(mark);
+		kfree(chunk);
+		return -ENOSPC;
+	}
+
+	spin_lock(&hash_lock);
+	if (tree->goner) {
+		spin_unlock(&hash_lock);
+		fsnotify_detach_mark(mark);
+		fsnotify_group_unlock(audit_tree_group);
+		fsnotify_free_mark(mark);
+		fsnotify_put_mark(mark);
+		kfree(chunk);
+		return 0;
+	}
+	replace_mark_chunk(mark, chunk);
+	chunk->owners[0].index = (1U << 31);
+	chunk->owners[0].owner = tree;
+	get_tree(tree);
+	list_add(&chunk->owners[0].list, &tree->chunks);
+	if (!tree->root) {
+		tree->root = chunk;
+		list_add(&tree->same_root, &chunk->trees);
+	}
+	chunk->key = inode_to_key(inode);
+	/*
+	 * Inserting into the hash table has to go last as once we do that RCU
+	 * readers can see the chunk.
+	 */
+	insert_hash(chunk);
+	spin_unlock(&hash_lock);
+	fsnotify_group_unlock(audit_tree_group);
+	/*
+	 * Drop our initial reference. When mark we point to is getting freed,
+	 * we get notification through ->freeing_mark callback and cleanup
+	 * chunk pointing to this mark.
+	 */
+	fsnotify_put_mark(mark);
+	return 0;
+}
+
+/* the first tagged inode becomes root of tree */
+static int tag_chunk(struct inode *inode, struct audit_tree *tree)
+{
+	struct fsnotify_mark *mark;
+	struct audit_chunk *chunk, *old;
+	struct audit_node *p;
+	int n;
+
+	fsnotify_group_lock(audit_tree_group);
+	mark = fsnotify_find_mark(&inode->i_fsnotify_marks, audit_tree_group);
+	if (!mark)
+		return create_chunk(inode, tree);
+
+	/*
+	 * Found mark is guaranteed to be attached and mark_mutex protects mark
+	 * from getting detached and thus it makes sure there is chunk attached
+	 * to the mark.
+	 */
+	/* are we already there? */
+	spin_lock(&hash_lock);
+	old = mark_chunk(mark);
+	for (n = 0; n < old->count; n++) {
+		if (old->owners[n].owner == tree) {
+			spin_unlock(&hash_lock);
+			fsnotify_group_unlock(audit_tree_group);
+			fsnotify_put_mark(mark);
+			return 0;
+		}
+	}
+	spin_unlock(&hash_lock);
+
+	chunk = alloc_chunk(old->count + 1);
+	if (!chunk) {
+		fsnotify_group_unlock(audit_tree_group);
+		fsnotify_put_mark(mark);
+		return -ENOMEM;
+	}
+
+	spin_lock(&hash_lock);
+	if (tree->goner) {
+		spin_unlock(&hash_lock);
+		fsnotify_group_unlock(audit_tree_group);
+		fsnotify_put_mark(mark);
+		kfree(chunk);
+		return 0;
+	}
+	p = &chunk->owners[chunk->count - 1];
+	p->index = (chunk->count - 1) | (1U<<31);
+	p->owner = tree;
+	get_tree(tree);
+	list_add(&p->list, &tree->chunks);
+	if (!tree->root) {
+		tree->root = chunk;
+		list_add(&tree->same_root, &chunk->trees);
+	}
+	/*
+	 * This has to go last when updating chunk as once replace_chunk() is
+	 * called, new RCU readers can see the new chunk.
+	 */
+	replace_chunk(chunk, old);
+	spin_unlock(&hash_lock);
+	fsnotify_group_unlock(audit_tree_group);
+	fsnotify_put_mark(mark); /* pair to fsnotify_find_mark */
+	audit_mark_put_chunk(old);
+
+	return 0;
+}
+
+static void audit_tree_log_remove_rule(struct audit_context *context,
+				       struct audit_krule *rule)
+{
+	struct audit_buffer *ab;
+
+	if (!audit_enabled)
+		return;
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
+	if (unlikely(!ab))
+		return;
+	audit_log_format(ab, "op=remove_rule dir=");
+	audit_log_untrustedstring(ab, rule->tree->pathname);
+	audit_log_key(ab, rule->filterkey);
+	audit_log_format(ab, " list=%d res=1", rule->listnr);
+	audit_log_end(ab);
+}
+
+static void kill_rules(struct audit_context *context, struct audit_tree *tree)
+{
+	struct audit_krule *rule, *next;
+	struct audit_entry *entry;
+
+	list_for_each_entry_safe(rule, next, &tree->rules, rlist) {
+		entry = container_of(rule, struct audit_entry, rule);
+
+		list_del_init(&rule->rlist);
+		if (rule->tree) {
+			/* not a half-baked one */
+			audit_tree_log_remove_rule(context, rule);
+			if (entry->rule.exe)
+				audit_remove_mark(entry->rule.exe);
+			rule->tree = NULL;
+			list_del_rcu(&entry->list);
+			list_del(&entry->rule.list);
+			call_rcu(&entry->rcu, audit_free_rule_rcu);
+		}
+	}
+}
+
+/*
+ * Remove tree from chunks. If 'tagged' is set, remove tree only from tagged
+ * chunks. The function expects tagged chunks are all at the beginning of the
+ * chunks list.
+ */
+static void prune_tree_chunks(struct audit_tree *victim, bool tagged)
+{
+	spin_lock(&hash_lock);
+	while (!list_empty(&victim->chunks)) {
+		struct audit_node *p;
+		struct audit_chunk *chunk;
+		struct fsnotify_mark *mark;
+
+		p = list_first_entry(&victim->chunks, struct audit_node, list);
+		/* have we run out of marked? */
+		if (tagged && !(p->index & (1U<<31)))
+			break;
+		chunk = find_chunk(p);
+		mark = chunk->mark;
+		remove_chunk_node(chunk, p);
+		/* Racing with audit_tree_freeing_mark()? */
+		if (!mark)
+			continue;
+		fsnotify_get_mark(mark);
+		spin_unlock(&hash_lock);
+
+		untag_chunk(chunk, mark);
+		fsnotify_put_mark(mark);
+
+		spin_lock(&hash_lock);
+	}
+	spin_unlock(&hash_lock);
+}
+
+/*
+ * finish killing struct audit_tree
+ */
+static void prune_one(struct audit_tree *victim)
+{
+	prune_tree_chunks(victim, false);
+	put_tree(victim);
+}
+
+/* trim the uncommitted chunks from tree */
+
+static void trim_marked(struct audit_tree *tree)
+{
+	struct list_head *p, *q;
+	spin_lock(&hash_lock);
+	if (tree->goner) {
+		spin_unlock(&hash_lock);
+		return;
+	}
+	/* reorder */
+	for (p = tree->chunks.next; p != &tree->chunks; p = q) {
+		struct audit_node *node = list_entry(p, struct audit_node, list);
+		q = p->next;
+		if (node->index & (1U<<31)) {
+			list_del_init(p);
+			list_add(p, &tree->chunks);
+		}
+	}
+	spin_unlock(&hash_lock);
+
+	prune_tree_chunks(tree, true);
+
+	spin_lock(&hash_lock);
+	if (!tree->root && !tree->goner) {
+		tree->goner = 1;
+		spin_unlock(&hash_lock);
+		mutex_lock(&audit_filter_mutex);
+		kill_rules(audit_context(), tree);
+		list_del_init(&tree->list);
+		mutex_unlock(&audit_filter_mutex);
+		prune_one(tree);
+	} else {
+		spin_unlock(&hash_lock);
+	}
+}
+
+static void audit_schedule_prune(void);
+
+/* called with audit_filter_mutex */
+int audit_remove_tree_rule(struct audit_krule *rule)
+{
+	struct audit_tree *tree;
+	tree = rule->tree;
+	if (tree) {
+		spin_lock(&hash_lock);
+		list_del_init(&rule->rlist);
+		if (list_empty(&tree->rules) && !tree->goner) {
+			tree->root = NULL;
+			list_del_init(&tree->same_root);
+			tree->goner = 1;
+			list_move(&tree->list, &prune_list);
+			rule->tree = NULL;
+			spin_unlock(&hash_lock);
+			audit_schedule_prune();
+			return 1;
+		}
+		rule->tree = NULL;
+		spin_unlock(&hash_lock);
+		return 1;
+	}
+	return 0;
+}
+
+static int compare_root(struct vfsmount *mnt, void *arg)
+{
+	return inode_to_key(d_backing_inode(mnt->mnt_root)) ==
+	       (unsigned long)arg;
+}
+
+void audit_trim_trees(void)
+{
+	struct list_head cursor;
+
+	mutex_lock(&audit_filter_mutex);
+	list_add(&cursor, &tree_list);
+	while (cursor.next != &tree_list) {
+		struct audit_tree *tree;
+		struct path path;
+		struct vfsmount *root_mnt;
+		struct audit_node *node;
+		int err;
+
+		tree = container_of(cursor.next, struct audit_tree, list);
+		get_tree(tree);
+		list_move(&cursor, &tree->list);
+		mutex_unlock(&audit_filter_mutex);
+
+		err = kern_path(tree->pathname, 0, &path);
+		if (err)
+			goto skip_it;
+
+		root_mnt = collect_mounts(&path);
+		path_put(&path);
+		if (IS_ERR(root_mnt))
+			goto skip_it;
+
+		spin_lock(&hash_lock);
+		list_for_each_entry(node, &tree->chunks, list) {
+			struct audit_chunk *chunk = find_chunk(node);
+			/* this could be NULL if the watch is dying else where... */
+			node->index |= 1U<<31;
+			if (iterate_mounts(compare_root,
+					   (void *)(chunk->key),
+					   root_mnt))
+				node->index &= ~(1U<<31);
+		}
+		spin_unlock(&hash_lock);
+		trim_marked(tree);
+		drop_collected_mounts(root_mnt);
+skip_it:
+		put_tree(tree);
+		mutex_lock(&audit_filter_mutex);
+	}
+	list_del(&cursor);
+	mutex_unlock(&audit_filter_mutex);
+}
+
+int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op)
+{
+
+	if (pathname[0] != '/' ||
+	    (rule->listnr != AUDIT_FILTER_EXIT &&
+	     rule->listnr != AUDIT_FILTER_URING_EXIT) ||
+	    op != Audit_equal ||
+	    rule->inode_f || rule->watch || rule->tree)
+		return -EINVAL;
+	rule->tree = alloc_tree(pathname);
+	if (!rule->tree)
+		return -ENOMEM;
+	return 0;
+}
+
+void audit_put_tree(struct audit_tree *tree)
+{
+	put_tree(tree);
+}
+
+static int tag_mount(struct vfsmount *mnt, void *arg)
+{
+	return tag_chunk(d_backing_inode(mnt->mnt_root), arg);
+}
+
+/*
+ * That gets run when evict_chunk() ends up needing to kill audit_tree.
+ * Runs from a separate thread.
+ */
+static int prune_tree_thread(void *unused)
+{
+	for (;;) {
+		if (list_empty(&prune_list)) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			schedule();
+		}
+
+		audit_ctl_lock();
+		mutex_lock(&audit_filter_mutex);
+
+		while (!list_empty(&prune_list)) {
+			struct audit_tree *victim;
+
+			victim = list_entry(prune_list.next,
+					struct audit_tree, list);
+			list_del_init(&victim->list);
+
+			mutex_unlock(&audit_filter_mutex);
+
+			prune_one(victim);
+
+			mutex_lock(&audit_filter_mutex);
+		}
+
+		mutex_unlock(&audit_filter_mutex);
+		audit_ctl_unlock();
+	}
+	return 0;
+}
+
+static int audit_launch_prune(void)
+{
+	if (prune_thread)
+		return 0;
+	prune_thread = kthread_run(prune_tree_thread, NULL,
+				"audit_prune_tree");
+	if (IS_ERR(prune_thread)) {
+		pr_err("cannot start thread audit_prune_tree");
+		prune_thread = NULL;
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+/* called with audit_filter_mutex */
+int audit_add_tree_rule(struct audit_krule *rule)
+{
+	struct audit_tree *seed = rule->tree, *tree;
+	struct path path;
+	struct vfsmount *mnt;
+	int err;
+
+	rule->tree = NULL;
+	list_for_each_entry(tree, &tree_list, list) {
+		if (!strcmp(seed->pathname, tree->pathname)) {
+			put_tree(seed);
+			rule->tree = tree;
+			list_add(&rule->rlist, &tree->rules);
+			return 0;
+		}
+	}
+	tree = seed;
+	list_add(&tree->list, &tree_list);
+	list_add(&rule->rlist, &tree->rules);
+	/* do not set rule->tree yet */
+	mutex_unlock(&audit_filter_mutex);
+
+	if (unlikely(!prune_thread)) {
+		err = audit_launch_prune();
+		if (err)
+			goto Err;
+	}
+
+	err = kern_path(tree->pathname, 0, &path);
+	if (err)
+		goto Err;
+	mnt = collect_mounts(&path);
+	path_put(&path);
+	if (IS_ERR(mnt)) {
+		err = PTR_ERR(mnt);
+		goto Err;
+	}
+
+	get_tree(tree);
+	err = iterate_mounts(tag_mount, tree, mnt);
+	drop_collected_mounts(mnt);
+
+	if (!err) {
+		struct audit_node *node;
+		spin_lock(&hash_lock);
+		list_for_each_entry(node, &tree->chunks, list)
+			node->index &= ~(1U<<31);
+		spin_unlock(&hash_lock);
+	} else {
+		trim_marked(tree);
+		goto Err;
+	}
+
+	mutex_lock(&audit_filter_mutex);
+	if (list_empty(&rule->rlist)) {
+		put_tree(tree);
+		return -ENOENT;
+	}
+	rule->tree = tree;
+	put_tree(tree);
+
+	return 0;
+Err:
+	mutex_lock(&audit_filter_mutex);
+	list_del_init(&tree->list);
+	list_del_init(&tree->rules);
+	put_tree(tree);
+	return err;
+}
+
+int audit_tag_tree(char *old, char *new)
+{
+	struct list_head cursor, barrier;
+	int failed = 0;
+	struct path path1, path2;
+	struct vfsmount *tagged;
+	int err;
+
+	err = kern_path(new, 0, &path2);
+	if (err)
+		return err;
+	tagged = collect_mounts(&path2);
+	path_put(&path2);
+	if (IS_ERR(tagged))
+		return PTR_ERR(tagged);
+
+	err = kern_path(old, 0, &path1);
+	if (err) {
+		drop_collected_mounts(tagged);
+		return err;
+	}
+
+	mutex_lock(&audit_filter_mutex);
+	list_add(&barrier, &tree_list);
+	list_add(&cursor, &barrier);
+
+	while (cursor.next != &tree_list) {
+		struct audit_tree *tree;
+		int good_one = 0;
+
+		tree = container_of(cursor.next, struct audit_tree, list);
+		get_tree(tree);
+		list_move(&cursor, &tree->list);
+		mutex_unlock(&audit_filter_mutex);
+
+		err = kern_path(tree->pathname, 0, &path2);
+		if (!err) {
+			good_one = path_is_under(&path1, &path2);
+			path_put(&path2);
+		}
+
+		if (!good_one) {
+			put_tree(tree);
+			mutex_lock(&audit_filter_mutex);
+			continue;
+		}
+
+		failed = iterate_mounts(tag_mount, tree, tagged);
+		if (failed) {
+			put_tree(tree);
+			mutex_lock(&audit_filter_mutex);
+			break;
+		}
+
+		mutex_lock(&audit_filter_mutex);
+		spin_lock(&hash_lock);
+		if (!tree->goner) {
+			list_move(&tree->list, &tree_list);
+		}
+		spin_unlock(&hash_lock);
+		put_tree(tree);
+	}
+
+	while (barrier.prev != &tree_list) {
+		struct audit_tree *tree;
+
+		tree = container_of(barrier.prev, struct audit_tree, list);
+		get_tree(tree);
+		list_move(&tree->list, &barrier);
+		mutex_unlock(&audit_filter_mutex);
+
+		if (!failed) {
+			struct audit_node *node;
+			spin_lock(&hash_lock);
+			list_for_each_entry(node, &tree->chunks, list)
+				node->index &= ~(1U<<31);
+			spin_unlock(&hash_lock);
+		} else {
+			trim_marked(tree);
+		}
+
+		put_tree(tree);
+		mutex_lock(&audit_filter_mutex);
+	}
+	list_del(&barrier);
+	list_del(&cursor);
+	mutex_unlock(&audit_filter_mutex);
+	path_put(&path1);
+	drop_collected_mounts(tagged);
+	return failed;
+}
+
+
+static void audit_schedule_prune(void)
+{
+	wake_up_process(prune_thread);
+}
+
+/*
+ * ... and that one is done if evict_chunk() decides to delay until the end
+ * of syscall.  Runs synchronously.
+ */
+void audit_kill_trees(struct audit_context *context)
+{
+	struct list_head *list = &context->killed_trees;
+
+	audit_ctl_lock();
+	mutex_lock(&audit_filter_mutex);
+
+	while (!list_empty(list)) {
+		struct audit_tree *victim;
+
+		victim = list_entry(list->next, struct audit_tree, list);
+		kill_rules(context, victim);
+		list_del_init(&victim->list);
+
+		mutex_unlock(&audit_filter_mutex);
+
+		prune_one(victim);
+
+		mutex_lock(&audit_filter_mutex);
+	}
+
+	mutex_unlock(&audit_filter_mutex);
+	audit_ctl_unlock();
+}
+
+/*
+ *  Here comes the stuff asynchronous to auditctl operations
+ */
+
+static void evict_chunk(struct audit_chunk *chunk)
+{
+	struct audit_tree *owner;
+	struct list_head *postponed = audit_killed_trees();
+	int need_prune = 0;
+	int n;
+
+	mutex_lock(&audit_filter_mutex);
+	spin_lock(&hash_lock);
+	while (!list_empty(&chunk->trees)) {
+		owner = list_entry(chunk->trees.next,
+				   struct audit_tree, same_root);
+		owner->goner = 1;
+		owner->root = NULL;
+		list_del_init(&owner->same_root);
+		spin_unlock(&hash_lock);
+		if (!postponed) {
+			kill_rules(audit_context(), owner);
+			list_move(&owner->list, &prune_list);
+			need_prune = 1;
+		} else {
+			list_move(&owner->list, postponed);
+		}
+		spin_lock(&hash_lock);
+	}
+	list_del_rcu(&chunk->hash);
+	for (n = 0; n < chunk->count; n++)
+		list_del_init(&chunk->owners[n].list);
+	spin_unlock(&hash_lock);
+	mutex_unlock(&audit_filter_mutex);
+	if (need_prune)
+		audit_schedule_prune();
+}
+
+static int audit_tree_handle_event(struct fsnotify_mark *mark, u32 mask,
+				   struct inode *inode, struct inode *dir,
+				   const struct qstr *file_name, u32 cookie)
+{
+	return 0;
+}
+
+static void audit_tree_freeing_mark(struct fsnotify_mark *mark,
+				    struct fsnotify_group *group)
+{
+	struct audit_chunk *chunk;
+
+	fsnotify_group_lock(mark->group);
+	spin_lock(&hash_lock);
+	chunk = mark_chunk(mark);
+	replace_mark_chunk(mark, NULL);
+	spin_unlock(&hash_lock);
+	fsnotify_group_unlock(mark->group);
+	if (chunk) {
+		evict_chunk(chunk);
+		audit_mark_put_chunk(chunk);
+	}
+
+	/*
+	 * We are guaranteed to have at least one reference to the mark from
+	 * either the inode or the caller of fsnotify_destroy_mark().
+	 */
+	BUG_ON(refcount_read(&mark->refcnt) < 1);
+}
+
+static const struct fsnotify_ops audit_tree_ops = {
+	.handle_inode_event = audit_tree_handle_event,
+	.freeing_mark = audit_tree_freeing_mark,
+	.free_mark = audit_tree_destroy_watch,
+};
+
+static int __init audit_tree_init(void)
+{
+	int i;
+
+	audit_tree_mark_cachep = KMEM_CACHE(audit_tree_mark, SLAB_PANIC);
+
+	audit_tree_group = fsnotify_alloc_group(&audit_tree_ops, 0);
+	if (IS_ERR(audit_tree_group))
+		audit_panic("cannot initialize fsnotify group for rectree watches");
+
+	for (i = 0; i < HASH_SIZE; i++)
+		INIT_LIST_HEAD(&chunk_hash_heads[i]);
+
+	return 0;
+}
+__initcall(audit_tree_init);
diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
new file mode 100644
index 000000000..7a98cd176
--- /dev/null
+++ b/kernel/audit_watch.c
@@ -0,0 +1,544 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* audit_watch.c -- watching inodes
+ *
+ * Copyright 2003-2009 Red Hat, Inc.
+ * Copyright 2005 Hewlett-Packard Development Company, L.P.
+ * Copyright 2005 IBM Corporation
+ */
+
+#include <linux/file.h>
+#include <linux/kernel.h>
+#include <linux/audit.h>
+#include <linux/kthread.h>
+#include <linux/mutex.h>
+#include <linux/fs.h>
+#include <linux/fsnotify_backend.h>
+#include <linux/namei.h>
+#include <linux/netlink.h>
+#include <linux/refcount.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include "audit.h"
+
+/*
+ * Reference counting:
+ *
+ * audit_parent: lifetime is from audit_init_parent() to receipt of an FS_IGNORED
+ * 	event.  Each audit_watch holds a reference to its associated parent.
+ *
+ * audit_watch: if added to lists, lifetime is from audit_init_watch() to
+ * 	audit_remove_watch().  Additionally, an audit_watch may exist
+ * 	temporarily to assist in searching existing filter data.  Each
+ * 	audit_krule holds a reference to its associated watch.
+ */
+
+struct audit_watch {
+	refcount_t		count;	/* reference count */
+	dev_t			dev;	/* associated superblock device */
+	char			*path;	/* insertion path */
+	unsigned long		ino;	/* associated inode number */
+	struct audit_parent	*parent; /* associated parent */
+	struct list_head	wlist;	/* entry in parent->watches list */
+	struct list_head	rules;	/* anchor for krule->rlist */
+};
+
+struct audit_parent {
+	struct list_head	watches; /* anchor for audit_watch->wlist */
+	struct fsnotify_mark mark; /* fsnotify mark on the inode */
+};
+
+/* fsnotify handle. */
+static struct fsnotify_group *audit_watch_group;
+
+/* fsnotify events we care about. */
+#define AUDIT_FS_WATCH (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
+			FS_MOVE_SELF | FS_UNMOUNT)
+
+static void audit_free_parent(struct audit_parent *parent)
+{
+	WARN_ON(!list_empty(&parent->watches));
+	kfree(parent);
+}
+
+static void audit_watch_free_mark(struct fsnotify_mark *entry)
+{
+	struct audit_parent *parent;
+
+	parent = container_of(entry, struct audit_parent, mark);
+	audit_free_parent(parent);
+}
+
+static void audit_get_parent(struct audit_parent *parent)
+{
+	if (likely(parent))
+		fsnotify_get_mark(&parent->mark);
+}
+
+static void audit_put_parent(struct audit_parent *parent)
+{
+	if (likely(parent))
+		fsnotify_put_mark(&parent->mark);
+}
+
+/*
+ * Find and return the audit_parent on the given inode.  If found a reference
+ * is taken on this parent.
+ */
+static inline struct audit_parent *audit_find_parent(struct inode *inode)
+{
+	struct audit_parent *parent = NULL;
+	struct fsnotify_mark *entry;
+
+	entry = fsnotify_find_mark(&inode->i_fsnotify_marks, audit_watch_group);
+	if (entry)
+		parent = container_of(entry, struct audit_parent, mark);
+
+	return parent;
+}
+
+void audit_get_watch(struct audit_watch *watch)
+{
+	refcount_inc(&watch->count);
+}
+
+void audit_put_watch(struct audit_watch *watch)
+{
+	if (refcount_dec_and_test(&watch->count)) {
+		WARN_ON(watch->parent);
+		WARN_ON(!list_empty(&watch->rules));
+		kfree(watch->path);
+		kfree(watch);
+	}
+}
+
+static void audit_remove_watch(struct audit_watch *watch)
+{
+	list_del(&watch->wlist);
+	audit_put_parent(watch->parent);
+	watch->parent = NULL;
+	audit_put_watch(watch); /* match initial get */
+}
+
+char *audit_watch_path(struct audit_watch *watch)
+{
+	return watch->path;
+}
+
+int audit_watch_compare(struct audit_watch *watch, unsigned long ino, dev_t dev)
+{
+	return (watch->ino != AUDIT_INO_UNSET) &&
+		(watch->ino == ino) &&
+		(watch->dev == dev);
+}
+
+/* Initialize a parent watch entry. */
+static struct audit_parent *audit_init_parent(const struct path *path)
+{
+	struct inode *inode = d_backing_inode(path->dentry);
+	struct audit_parent *parent;
+	int ret;
+
+	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
+	if (unlikely(!parent))
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&parent->watches);
+
+	fsnotify_init_mark(&parent->mark, audit_watch_group);
+	parent->mark.mask = AUDIT_FS_WATCH;
+	ret = fsnotify_add_inode_mark(&parent->mark, inode, 0);
+	if (ret < 0) {
+		audit_free_parent(parent);
+		return ERR_PTR(ret);
+	}
+
+	return parent;
+}
+
+/* Initialize a watch entry. */
+static struct audit_watch *audit_init_watch(char *path)
+{
+	struct audit_watch *watch;
+
+	watch = kzalloc(sizeof(*watch), GFP_KERNEL);
+	if (unlikely(!watch))
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&watch->rules);
+	refcount_set(&watch->count, 1);
+	watch->path = path;
+	watch->dev = AUDIT_DEV_UNSET;
+	watch->ino = AUDIT_INO_UNSET;
+
+	return watch;
+}
+
+/* Translate a watch string to kernel representation. */
+int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op)
+{
+	struct audit_watch *watch;
+
+	if (!audit_watch_group)
+		return -EOPNOTSUPP;
+
+	if (path[0] != '/' || path[len-1] == '/' ||
+	    (krule->listnr != AUDIT_FILTER_EXIT &&
+	     krule->listnr != AUDIT_FILTER_URING_EXIT) ||
+	    op != Audit_equal ||
+	    krule->inode_f || krule->watch || krule->tree)
+		return -EINVAL;
+
+	watch = audit_init_watch(path);
+	if (IS_ERR(watch))
+		return PTR_ERR(watch);
+
+	krule->watch = watch;
+
+	return 0;
+}
+
+/* Duplicate the given audit watch.  The new watch's rules list is initialized
+ * to an empty list and wlist is undefined. */
+static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
+{
+	char *path;
+	struct audit_watch *new;
+
+	path = kstrdup(old->path, GFP_KERNEL);
+	if (unlikely(!path))
+		return ERR_PTR(-ENOMEM);
+
+	new = audit_init_watch(path);
+	if (IS_ERR(new)) {
+		kfree(path);
+		goto out;
+	}
+
+	new->dev = old->dev;
+	new->ino = old->ino;
+	audit_get_parent(old->parent);
+	new->parent = old->parent;
+
+out:
+	return new;
+}
+
+static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watch *w, char *op)
+{
+	struct audit_buffer *ab;
+
+	if (!audit_enabled)
+		return;
+	ab = audit_log_start(audit_context(), GFP_NOFS, AUDIT_CONFIG_CHANGE);
+	if (!ab)
+		return;
+	audit_log_session_info(ab);
+	audit_log_format(ab, "op=%s path=", op);
+	audit_log_untrustedstring(ab, w->path);
+	audit_log_key(ab, r->filterkey);
+	audit_log_format(ab, " list=%d res=1", r->listnr);
+	audit_log_end(ab);
+}
+
+/* Update inode info in audit rules based on filesystem event. */
+static void audit_update_watch(struct audit_parent *parent,
+			       const struct qstr *dname, dev_t dev,
+			       unsigned long ino, unsigned invalidating)
+{
+	struct audit_watch *owatch, *nwatch, *nextw;
+	struct audit_krule *r, *nextr;
+	struct audit_entry *oentry, *nentry;
+
+	mutex_lock(&audit_filter_mutex);
+	/* Run all of the watches on this parent looking for the one that
+	 * matches the given dname */
+	list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
+		if (audit_compare_dname_path(dname, owatch->path,
+					     AUDIT_NAME_FULL))
+			continue;
+
+		/* If the update involves invalidating rules, do the inode-based
+		 * filtering now, so we don't omit records. */
+		if (invalidating && !audit_dummy_context())
+			audit_filter_inodes(current, audit_context());
+
+		/* updating ino will likely change which audit_hash_list we
+		 * are on so we need a new watch for the new list */
+		nwatch = audit_dupe_watch(owatch);
+		if (IS_ERR(nwatch)) {
+			mutex_unlock(&audit_filter_mutex);
+			audit_panic("error updating watch, skipping");
+			return;
+		}
+		nwatch->dev = dev;
+		nwatch->ino = ino;
+
+		list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
+
+			oentry = container_of(r, struct audit_entry, rule);
+			list_del(&oentry->rule.rlist);
+			list_del_rcu(&oentry->list);
+
+			nentry = audit_dupe_rule(&oentry->rule);
+			if (IS_ERR(nentry)) {
+				list_del(&oentry->rule.list);
+				audit_panic("error updating watch, removing");
+			} else {
+				int h = audit_hash_ino((u32)ino);
+
+				/*
+				 * nentry->rule.watch == oentry->rule.watch so
+				 * we must drop that reference and set it to our
+				 * new watch.
+				 */
+				audit_put_watch(nentry->rule.watch);
+				audit_get_watch(nwatch);
+				nentry->rule.watch = nwatch;
+				list_add(&nentry->rule.rlist, &nwatch->rules);
+				list_add_rcu(&nentry->list, &audit_inode_hash[h]);
+				list_replace(&oentry->rule.list,
+					     &nentry->rule.list);
+			}
+			if (oentry->rule.exe)
+				audit_remove_mark(oentry->rule.exe);
+
+			call_rcu(&oentry->rcu, audit_free_rule_rcu);
+		}
+
+		audit_remove_watch(owatch);
+		goto add_watch_to_parent; /* event applies to a single watch */
+	}
+	mutex_unlock(&audit_filter_mutex);
+	return;
+
+add_watch_to_parent:
+	list_add(&nwatch->wlist, &parent->watches);
+	mutex_unlock(&audit_filter_mutex);
+	return;
+}
+
+/* Remove all watches & rules associated with a parent that is going away. */
+static void audit_remove_parent_watches(struct audit_parent *parent)
+{
+	struct audit_watch *w, *nextw;
+	struct audit_krule *r, *nextr;
+	struct audit_entry *e;
+
+	mutex_lock(&audit_filter_mutex);
+	list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
+		list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
+			e = container_of(r, struct audit_entry, rule);
+			audit_watch_log_rule_change(r, w, "remove_rule");
+			if (e->rule.exe)
+				audit_remove_mark(e->rule.exe);
+			list_del(&r->rlist);
+			list_del(&r->list);
+			list_del_rcu(&e->list);
+			call_rcu(&e->rcu, audit_free_rule_rcu);
+		}
+		audit_remove_watch(w);
+	}
+	mutex_unlock(&audit_filter_mutex);
+
+	fsnotify_destroy_mark(&parent->mark, audit_watch_group);
+}
+
+/* Get path information necessary for adding watches. */
+static int audit_get_nd(struct audit_watch *watch, struct path *parent)
+{
+	struct dentry *d = kern_path_locked(watch->path, parent);
+	if (IS_ERR(d))
+		return PTR_ERR(d);
+	if (d_is_positive(d)) {
+		/* update watch filter fields */
+		watch->dev = d->d_sb->s_dev;
+		watch->ino = d_backing_inode(d)->i_ino;
+	}
+	inode_unlock(d_backing_inode(parent->dentry));
+	dput(d);
+	return 0;
+}
+
+/* Associate the given rule with an existing parent.
+ * Caller must hold audit_filter_mutex. */
+static void audit_add_to_parent(struct audit_krule *krule,
+				struct audit_parent *parent)
+{
+	struct audit_watch *w, *watch = krule->watch;
+	int watch_found = 0;
+
+	BUG_ON(!mutex_is_locked(&audit_filter_mutex));
+
+	list_for_each_entry(w, &parent->watches, wlist) {
+		if (strcmp(watch->path, w->path))
+			continue;
+
+		watch_found = 1;
+
+		/* put krule's ref to temporary watch */
+		audit_put_watch(watch);
+
+		audit_get_watch(w);
+		krule->watch = watch = w;
+
+		audit_put_parent(parent);
+		break;
+	}
+
+	if (!watch_found) {
+		watch->parent = parent;
+
+		audit_get_watch(watch);
+		list_add(&watch->wlist, &parent->watches);
+	}
+	list_add(&krule->rlist, &watch->rules);
+}
+
+/* Find a matching watch entry, or add this one.
+ * Caller must hold audit_filter_mutex. */
+int audit_add_watch(struct audit_krule *krule, struct list_head **list)
+{
+	struct audit_watch *watch = krule->watch;
+	struct audit_parent *parent;
+	struct path parent_path;
+	int h, ret = 0;
+
+	/*
+	 * When we will be calling audit_add_to_parent, krule->watch might have
+	 * been updated and watch might have been freed.
+	 * So we need to keep a reference of watch.
+	 */
+	audit_get_watch(watch);
+
+	mutex_unlock(&audit_filter_mutex);
+
+	/* Avoid calling path_lookup under audit_filter_mutex. */
+	ret = audit_get_nd(watch, &parent_path);
+
+	/* caller expects mutex locked */
+	mutex_lock(&audit_filter_mutex);
+
+	if (ret) {
+		audit_put_watch(watch);
+		return ret;
+	}
+
+	/* either find an old parent or attach a new one */
+	parent = audit_find_parent(d_backing_inode(parent_path.dentry));
+	if (!parent) {
+		parent = audit_init_parent(&parent_path);
+		if (IS_ERR(parent)) {
+			ret = PTR_ERR(parent);
+			goto error;
+		}
+	}
+
+	audit_add_to_parent(krule, parent);
+
+	h = audit_hash_ino((u32)watch->ino);
+	*list = &audit_inode_hash[h];
+error:
+	path_put(&parent_path);
+	audit_put_watch(watch);
+	return ret;
+}
+
+void audit_remove_watch_rule(struct audit_krule *krule)
+{
+	struct audit_watch *watch = krule->watch;
+	struct audit_parent *parent = watch->parent;
+
+	list_del(&krule->rlist);
+
+	if (list_empty(&watch->rules)) {
+		/*
+		 * audit_remove_watch() drops our reference to 'parent' which
+		 * can get freed. Grab our own reference to be safe.
+		 */
+		audit_get_parent(parent);
+		audit_remove_watch(watch);
+		if (list_empty(&parent->watches))
+			fsnotify_destroy_mark(&parent->mark, audit_watch_group);
+		audit_put_parent(parent);
+	}
+}
+
+/* Update watch data in audit rules based on fsnotify events. */
+static int audit_watch_handle_event(struct fsnotify_mark *inode_mark, u32 mask,
+				    struct inode *inode, struct inode *dir,
+				    const struct qstr *dname, u32 cookie)
+{
+	struct audit_parent *parent;
+
+	parent = container_of(inode_mark, struct audit_parent, mark);
+
+	if (WARN_ON_ONCE(inode_mark->group != audit_watch_group))
+		return 0;
+
+	if (mask & (FS_CREATE|FS_MOVED_TO) && inode)
+		audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0);
+	else if (mask & (FS_DELETE|FS_MOVED_FROM))
+		audit_update_watch(parent, dname, AUDIT_DEV_UNSET, AUDIT_INO_UNSET, 1);
+	else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF))
+		audit_remove_parent_watches(parent);
+
+	return 0;
+}
+
+static const struct fsnotify_ops audit_watch_fsnotify_ops = {
+	.handle_inode_event =	audit_watch_handle_event,
+	.free_mark =		audit_watch_free_mark,
+};
+
+static int __init audit_watch_init(void)
+{
+	audit_watch_group = fsnotify_alloc_group(&audit_watch_fsnotify_ops, 0);
+	if (IS_ERR(audit_watch_group)) {
+		audit_watch_group = NULL;
+		audit_panic("cannot create audit fsnotify group");
+	}
+	return 0;
+}
+device_initcall(audit_watch_init);
+
+int audit_dupe_exe(struct audit_krule *new, struct audit_krule *old)
+{
+	struct audit_fsnotify_mark *audit_mark;
+	char *pathname;
+
+	pathname = kstrdup(audit_mark_path(old->exe), GFP_KERNEL);
+	if (!pathname)
+		return -ENOMEM;
+
+	audit_mark = audit_alloc_mark(new, pathname, strlen(pathname));
+	if (IS_ERR(audit_mark)) {
+		kfree(pathname);
+		return PTR_ERR(audit_mark);
+	}
+	new->exe = audit_mark;
+
+	return 0;
+}
+
+int audit_exe_compare(struct task_struct *tsk, struct audit_fsnotify_mark *mark)
+{
+	struct file *exe_file;
+	unsigned long ino;
+	dev_t dev;
+
+	/* only do exe filtering if we are recording @current events/records */
+	if (tsk != current)
+		return 0;
+
+	if (!current->mm)
+		return 0;
+	exe_file = get_mm_exe_file(current->mm);
+	if (!exe_file)
+		return 0;
+	ino = file_inode(exe_file)->i_ino;
+	dev = file_inode(exe_file)->i_sb->s_dev;
+	fput(exe_file);
+
+	return audit_mark_compare(mark, ino, dev);
+}
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
new file mode 100644
index 000000000..42d99896e
--- /dev/null
+++ b/kernel/auditfilter.c
@@ -0,0 +1,1455 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* auditfilter.c -- filtering of audit events
+ *
+ * Copyright 2003-2004 Red Hat, Inc.
+ * Copyright 2005 Hewlett-Packard Development Company, L.P.
+ * Copyright 2005 IBM Corporation
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/audit.h>
+#include <linux/kthread.h>
+#include <linux/mutex.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/netlink.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include <net/net_namespace.h>
+#include <net/sock.h>
+#include "audit.h"
+
+/*
+ * Locking model:
+ *
+ * audit_filter_mutex:
+ *		Synchronizes writes and blocking reads of audit's filterlist
+ *		data.  Rcu is used to traverse the filterlist and access
+ *		contents of structs audit_entry, audit_watch and opaque
+ *		LSM rules during filtering.  If modified, these structures
+ *		must be copied and replace their counterparts in the filterlist.
+ *		An audit_parent struct is not accessed during filtering, so may
+ *		be written directly provided audit_filter_mutex is held.
+ */
+
+/* Audit filter lists, defined in <linux/audit.h> */
+struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
+	LIST_HEAD_INIT(audit_filter_list[0]),
+	LIST_HEAD_INIT(audit_filter_list[1]),
+	LIST_HEAD_INIT(audit_filter_list[2]),
+	LIST_HEAD_INIT(audit_filter_list[3]),
+	LIST_HEAD_INIT(audit_filter_list[4]),
+	LIST_HEAD_INIT(audit_filter_list[5]),
+	LIST_HEAD_INIT(audit_filter_list[6]),
+	LIST_HEAD_INIT(audit_filter_list[7]),
+#if AUDIT_NR_FILTERS != 8
+#error Fix audit_filter_list initialiser
+#endif
+};
+static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
+	LIST_HEAD_INIT(audit_rules_list[0]),
+	LIST_HEAD_INIT(audit_rules_list[1]),
+	LIST_HEAD_INIT(audit_rules_list[2]),
+	LIST_HEAD_INIT(audit_rules_list[3]),
+	LIST_HEAD_INIT(audit_rules_list[4]),
+	LIST_HEAD_INIT(audit_rules_list[5]),
+	LIST_HEAD_INIT(audit_rules_list[6]),
+	LIST_HEAD_INIT(audit_rules_list[7]),
+};
+
+DEFINE_MUTEX(audit_filter_mutex);
+
+static void audit_free_lsm_field(struct audit_field *f)
+{
+	switch (f->type) {
+	case AUDIT_SUBJ_USER:
+	case AUDIT_SUBJ_ROLE:
+	case AUDIT_SUBJ_TYPE:
+	case AUDIT_SUBJ_SEN:
+	case AUDIT_SUBJ_CLR:
+	case AUDIT_OBJ_USER:
+	case AUDIT_OBJ_ROLE:
+	case AUDIT_OBJ_TYPE:
+	case AUDIT_OBJ_LEV_LOW:
+	case AUDIT_OBJ_LEV_HIGH:
+		kfree(f->lsm_str);
+		security_audit_rule_free(f->lsm_rule);
+	}
+}
+
+static inline void audit_free_rule(struct audit_entry *e)
+{
+	int i;
+	struct audit_krule *erule = &e->rule;
+
+	/* some rules don't have associated watches */
+	if (erule->watch)
+		audit_put_watch(erule->watch);
+	if (erule->fields)
+		for (i = 0; i < erule->field_count; i++)
+			audit_free_lsm_field(&erule->fields[i]);
+	kfree(erule->fields);
+	kfree(erule->filterkey);
+	kfree(e);
+}
+
+void audit_free_rule_rcu(struct rcu_head *head)
+{
+	struct audit_entry *e = container_of(head, struct audit_entry, rcu);
+	audit_free_rule(e);
+}
+
+/* Initialize an audit filterlist entry. */
+static inline struct audit_entry *audit_init_entry(u32 field_count)
+{
+	struct audit_entry *entry;
+	struct audit_field *fields;
+
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	if (unlikely(!entry))
+		return NULL;
+
+	fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
+	if (unlikely(!fields)) {
+		kfree(entry);
+		return NULL;
+	}
+	entry->rule.fields = fields;
+
+	return entry;
+}
+
+/* Unpack a filter field's string representation from user-space
+ * buffer. */
+char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
+{
+	char *str;
+
+	if (!*bufp || (len == 0) || (len > *remain))
+		return ERR_PTR(-EINVAL);
+
+	/* Of the currently implemented string fields, PATH_MAX
+	 * defines the longest valid length.
+	 */
+	if (len > PATH_MAX)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	str = kmalloc(len + 1, GFP_KERNEL);
+	if (unlikely(!str))
+		return ERR_PTR(-ENOMEM);
+
+	memcpy(str, *bufp, len);
+	str[len] = 0;
+	*bufp += len;
+	*remain -= len;
+
+	return str;
+}
+
+/* Translate an inode field to kernel representation. */
+static inline int audit_to_inode(struct audit_krule *krule,
+				 struct audit_field *f)
+{
+	if ((krule->listnr != AUDIT_FILTER_EXIT &&
+	     krule->listnr != AUDIT_FILTER_URING_EXIT) ||
+	    krule->inode_f || krule->watch || krule->tree ||
+	    (f->op != Audit_equal && f->op != Audit_not_equal))
+		return -EINVAL;
+
+	krule->inode_f = f;
+	return 0;
+}
+
+static __u32 *classes[AUDIT_SYSCALL_CLASSES];
+
+int __init audit_register_class(int class, unsigned *list)
+{
+	__u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+	while (*list != ~0U) {
+		unsigned n = *list++;
+		if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
+			kfree(p);
+			return -EINVAL;
+		}
+		p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
+	}
+	if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
+		kfree(p);
+		return -EINVAL;
+	}
+	classes[class] = p;
+	return 0;
+}
+
+int audit_match_class(int class, unsigned syscall)
+{
+	if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
+		return 0;
+	if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
+		return 0;
+	return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
+}
+
+#ifdef CONFIG_AUDITSYSCALL
+static inline int audit_match_class_bits(int class, u32 *mask)
+{
+	int i;
+
+	if (classes[class]) {
+		for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
+			if (mask[i] & classes[class][i])
+				return 0;
+	}
+	return 1;
+}
+
+static int audit_match_signal(struct audit_entry *entry)
+{
+	struct audit_field *arch = entry->rule.arch_f;
+
+	if (!arch) {
+		/* When arch is unspecified, we must check both masks on biarch
+		 * as syscall number alone is ambiguous. */
+		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
+					       entry->rule.mask) &&
+			audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
+					       entry->rule.mask));
+	}
+
+	switch(audit_classify_arch(arch->val)) {
+	case 0: /* native */
+		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
+					       entry->rule.mask));
+	case 1: /* 32bit on biarch */
+		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
+					       entry->rule.mask));
+	default:
+		return 1;
+	}
+}
+#endif
+
+/* Common user-space to kernel rule translation. */
+static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
+{
+	unsigned listnr;
+	struct audit_entry *entry;
+	int i, err;
+
+	err = -EINVAL;
+	listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
+	switch(listnr) {
+	default:
+		goto exit_err;
+#ifdef CONFIG_AUDITSYSCALL
+	case AUDIT_FILTER_ENTRY:
+		pr_err("AUDIT_FILTER_ENTRY is deprecated\n");
+		goto exit_err;
+	case AUDIT_FILTER_EXIT:
+	case AUDIT_FILTER_URING_EXIT:
+	case AUDIT_FILTER_TASK:
+#endif
+	case AUDIT_FILTER_USER:
+	case AUDIT_FILTER_EXCLUDE:
+	case AUDIT_FILTER_FS:
+		;
+	}
+	if (unlikely(rule->action == AUDIT_POSSIBLE)) {
+		pr_err("AUDIT_POSSIBLE is deprecated\n");
+		goto exit_err;
+	}
+	if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
+		goto exit_err;
+	if (rule->field_count > AUDIT_MAX_FIELDS)
+		goto exit_err;
+
+	err = -ENOMEM;
+	entry = audit_init_entry(rule->field_count);
+	if (!entry)
+		goto exit_err;
+
+	entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
+	entry->rule.listnr = listnr;
+	entry->rule.action = rule->action;
+	entry->rule.field_count = rule->field_count;
+
+	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
+		entry->rule.mask[i] = rule->mask[i];
+
+	for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
+		int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
+		__u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
+		__u32 *class;
+
+		if (!(*p & AUDIT_BIT(bit)))
+			continue;
+		*p &= ~AUDIT_BIT(bit);
+		class = classes[i];
+		if (class) {
+			int j;
+			for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
+				entry->rule.mask[j] |= class[j];
+		}
+	}
+
+	return entry;
+
+exit_err:
+	return ERR_PTR(err);
+}
+
+static u32 audit_ops[] =
+{
+	[Audit_equal] = AUDIT_EQUAL,
+	[Audit_not_equal] = AUDIT_NOT_EQUAL,
+	[Audit_bitmask] = AUDIT_BIT_MASK,
+	[Audit_bittest] = AUDIT_BIT_TEST,
+	[Audit_lt] = AUDIT_LESS_THAN,
+	[Audit_gt] = AUDIT_GREATER_THAN,
+	[Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
+	[Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
+};
+
+static u32 audit_to_op(u32 op)
+{
+	u32 n;
+	for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
+		;
+	return n;
+}
+
+/* check if an audit field is valid */
+static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
+{
+	switch (f->type) {
+	case AUDIT_MSGTYPE:
+		if (entry->rule.listnr != AUDIT_FILTER_EXCLUDE &&
+		    entry->rule.listnr != AUDIT_FILTER_USER)
+			return -EINVAL;
+		break;
+	case AUDIT_FSTYPE:
+		if (entry->rule.listnr != AUDIT_FILTER_FS)
+			return -EINVAL;
+		break;
+	case AUDIT_PERM:
+		if (entry->rule.listnr == AUDIT_FILTER_URING_EXIT)
+			return -EINVAL;
+		break;
+	}
+
+	switch (entry->rule.listnr) {
+	case AUDIT_FILTER_FS:
+		switch(f->type) {
+		case AUDIT_FSTYPE:
+		case AUDIT_FILTERKEY:
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	/* Check for valid field type and op */
+	switch (f->type) {
+	case AUDIT_ARG0:
+	case AUDIT_ARG1:
+	case AUDIT_ARG2:
+	case AUDIT_ARG3:
+	case AUDIT_PERS: /* <uapi/linux/personality.h> */
+	case AUDIT_DEVMINOR:
+		/* all ops are valid */
+		break;
+	case AUDIT_UID:
+	case AUDIT_EUID:
+	case AUDIT_SUID:
+	case AUDIT_FSUID:
+	case AUDIT_LOGINUID:
+	case AUDIT_OBJ_UID:
+	case AUDIT_GID:
+	case AUDIT_EGID:
+	case AUDIT_SGID:
+	case AUDIT_FSGID:
+	case AUDIT_OBJ_GID:
+	case AUDIT_PID:
+	case AUDIT_MSGTYPE:
+	case AUDIT_PPID:
+	case AUDIT_DEVMAJOR:
+	case AUDIT_EXIT:
+	case AUDIT_SUCCESS:
+	case AUDIT_INODE:
+	case AUDIT_SESSIONID:
+	case AUDIT_SUBJ_SEN:
+	case AUDIT_SUBJ_CLR:
+	case AUDIT_OBJ_LEV_LOW:
+	case AUDIT_OBJ_LEV_HIGH:
+	case AUDIT_SADDR_FAM:
+		/* bit ops are only useful on syscall args */
+		if (f->op == Audit_bitmask || f->op == Audit_bittest)
+			return -EINVAL;
+		break;
+	case AUDIT_SUBJ_USER:
+	case AUDIT_SUBJ_ROLE:
+	case AUDIT_SUBJ_TYPE:
+	case AUDIT_OBJ_USER:
+	case AUDIT_OBJ_ROLE:
+	case AUDIT_OBJ_TYPE:
+	case AUDIT_WATCH:
+	case AUDIT_DIR:
+	case AUDIT_FILTERKEY:
+	case AUDIT_LOGINUID_SET:
+	case AUDIT_ARCH:
+	case AUDIT_FSTYPE:
+	case AUDIT_PERM:
+	case AUDIT_FILETYPE:
+	case AUDIT_FIELD_COMPARE:
+	case AUDIT_EXE:
+		/* only equal and not equal valid ops */
+		if (f->op != Audit_not_equal && f->op != Audit_equal)
+			return -EINVAL;
+		break;
+	default:
+		/* field not recognized */
+		return -EINVAL;
+	}
+
+	/* Check for select valid field values */
+	switch (f->type) {
+	case AUDIT_LOGINUID_SET:
+		if ((f->val != 0) && (f->val != 1))
+			return -EINVAL;
+		break;
+	case AUDIT_PERM:
+		if (f->val & ~15)
+			return -EINVAL;
+		break;
+	case AUDIT_FILETYPE:
+		if (f->val & ~S_IFMT)
+			return -EINVAL;
+		break;
+	case AUDIT_FIELD_COMPARE:
+		if (f->val > AUDIT_MAX_FIELD_COMPARE)
+			return -EINVAL;
+		break;
+	case AUDIT_SADDR_FAM:
+		if (f->val >= AF_MAX)
+			return -EINVAL;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/* Translate struct audit_rule_data to kernel's rule representation. */
+static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
+					       size_t datasz)
+{
+	int err = 0;
+	struct audit_entry *entry;
+	void *bufp;
+	size_t remain = datasz - sizeof(struct audit_rule_data);
+	int i;
+	char *str;
+	struct audit_fsnotify_mark *audit_mark;
+
+	entry = audit_to_entry_common(data);
+	if (IS_ERR(entry))
+		goto exit_nofree;
+
+	bufp = data->buf;
+	for (i = 0; i < data->field_count; i++) {
+		struct audit_field *f = &entry->rule.fields[i];
+		u32 f_val;
+
+		err = -EINVAL;
+
+		f->op = audit_to_op(data->fieldflags[i]);
+		if (f->op == Audit_bad)
+			goto exit_free;
+
+		f->type = data->fields[i];
+		f_val = data->values[i];
+
+		/* Support legacy tests for a valid loginuid */
+		if ((f->type == AUDIT_LOGINUID) && (f_val == AUDIT_UID_UNSET)) {
+			f->type = AUDIT_LOGINUID_SET;
+			f_val = 0;
+			entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
+		}
+
+		err = audit_field_valid(entry, f);
+		if (err)
+			goto exit_free;
+
+		err = -EINVAL;
+		switch (f->type) {
+		case AUDIT_LOGINUID:
+		case AUDIT_UID:
+		case AUDIT_EUID:
+		case AUDIT_SUID:
+		case AUDIT_FSUID:
+		case AUDIT_OBJ_UID:
+			f->uid = make_kuid(current_user_ns(), f_val);
+			if (!uid_valid(f->uid))
+				goto exit_free;
+			break;
+		case AUDIT_GID:
+		case AUDIT_EGID:
+		case AUDIT_SGID:
+		case AUDIT_FSGID:
+		case AUDIT_OBJ_GID:
+			f->gid = make_kgid(current_user_ns(), f_val);
+			if (!gid_valid(f->gid))
+				goto exit_free;
+			break;
+		case AUDIT_ARCH:
+			f->val = f_val;
+			entry->rule.arch_f = f;
+			break;
+		case AUDIT_SUBJ_USER:
+		case AUDIT_SUBJ_ROLE:
+		case AUDIT_SUBJ_TYPE:
+		case AUDIT_SUBJ_SEN:
+		case AUDIT_SUBJ_CLR:
+		case AUDIT_OBJ_USER:
+		case AUDIT_OBJ_ROLE:
+		case AUDIT_OBJ_TYPE:
+		case AUDIT_OBJ_LEV_LOW:
+		case AUDIT_OBJ_LEV_HIGH:
+			str = audit_unpack_string(&bufp, &remain, f_val);
+			if (IS_ERR(str)) {
+				err = PTR_ERR(str);
+				goto exit_free;
+			}
+			entry->rule.buflen += f_val;
+			f->lsm_str = str;
+			err = security_audit_rule_init(f->type, f->op, str,
+						       (void **)&f->lsm_rule);
+			/* Keep currently invalid fields around in case they
+			 * become valid after a policy reload. */
+			if (err == -EINVAL) {
+				pr_warn("audit rule for LSM \'%s\' is invalid\n",
+					str);
+				err = 0;
+			} else if (err)
+				goto exit_free;
+			break;
+		case AUDIT_WATCH:
+			str = audit_unpack_string(&bufp, &remain, f_val);
+			if (IS_ERR(str)) {
+				err = PTR_ERR(str);
+				goto exit_free;
+			}
+			err = audit_to_watch(&entry->rule, str, f_val, f->op);
+			if (err) {
+				kfree(str);
+				goto exit_free;
+			}
+			entry->rule.buflen += f_val;
+			break;
+		case AUDIT_DIR:
+			str = audit_unpack_string(&bufp, &remain, f_val);
+			if (IS_ERR(str)) {
+				err = PTR_ERR(str);
+				goto exit_free;
+			}
+			err = audit_make_tree(&entry->rule, str, f->op);
+			kfree(str);
+			if (err)
+				goto exit_free;
+			entry->rule.buflen += f_val;
+			break;
+		case AUDIT_INODE:
+			f->val = f_val;
+			err = audit_to_inode(&entry->rule, f);
+			if (err)
+				goto exit_free;
+			break;
+		case AUDIT_FILTERKEY:
+			if (entry->rule.filterkey || f_val > AUDIT_MAX_KEY_LEN)
+				goto exit_free;
+			str = audit_unpack_string(&bufp, &remain, f_val);
+			if (IS_ERR(str)) {
+				err = PTR_ERR(str);
+				goto exit_free;
+			}
+			entry->rule.buflen += f_val;
+			entry->rule.filterkey = str;
+			break;
+		case AUDIT_EXE:
+			if (entry->rule.exe || f_val > PATH_MAX)
+				goto exit_free;
+			str = audit_unpack_string(&bufp, &remain, f_val);
+			if (IS_ERR(str)) {
+				err = PTR_ERR(str);
+				goto exit_free;
+			}
+			audit_mark = audit_alloc_mark(&entry->rule, str, f_val);
+			if (IS_ERR(audit_mark)) {
+				kfree(str);
+				err = PTR_ERR(audit_mark);
+				goto exit_free;
+			}
+			entry->rule.buflen += f_val;
+			entry->rule.exe = audit_mark;
+			break;
+		default:
+			f->val = f_val;
+			break;
+		}
+	}
+
+	if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
+		entry->rule.inode_f = NULL;
+
+exit_nofree:
+	return entry;
+
+exit_free:
+	if (entry->rule.tree)
+		audit_put_tree(entry->rule.tree); /* that's the temporary one */
+	if (entry->rule.exe)
+		audit_remove_mark(entry->rule.exe); /* that's the template one */
+	audit_free_rule(entry);
+	return ERR_PTR(err);
+}
+
+/* Pack a filter field's string representation into data block. */
+static inline size_t audit_pack_string(void **bufp, const char *str)
+{
+	size_t len = strlen(str);
+
+	memcpy(*bufp, str, len);
+	*bufp += len;
+
+	return len;
+}
+
+/* Translate kernel rule representation to struct audit_rule_data. */
+static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
+{
+	struct audit_rule_data *data;
+	void *bufp;
+	int i;
+
+	data = kmalloc(struct_size(data, buf, krule->buflen), GFP_KERNEL);
+	if (unlikely(!data))
+		return NULL;
+	memset(data, 0, sizeof(*data));
+
+	data->flags = krule->flags | krule->listnr;
+	data->action = krule->action;
+	data->field_count = krule->field_count;
+	bufp = data->buf;
+	for (i = 0; i < data->field_count; i++) {
+		struct audit_field *f = &krule->fields[i];
+
+		data->fields[i] = f->type;
+		data->fieldflags[i] = audit_ops[f->op];
+		switch(f->type) {
+		case AUDIT_SUBJ_USER:
+		case AUDIT_SUBJ_ROLE:
+		case AUDIT_SUBJ_TYPE:
+		case AUDIT_SUBJ_SEN:
+		case AUDIT_SUBJ_CLR:
+		case AUDIT_OBJ_USER:
+		case AUDIT_OBJ_ROLE:
+		case AUDIT_OBJ_TYPE:
+		case AUDIT_OBJ_LEV_LOW:
+		case AUDIT_OBJ_LEV_HIGH:
+			data->buflen += data->values[i] =
+				audit_pack_string(&bufp, f->lsm_str);
+			break;
+		case AUDIT_WATCH:
+			data->buflen += data->values[i] =
+				audit_pack_string(&bufp,
+						  audit_watch_path(krule->watch));
+			break;
+		case AUDIT_DIR:
+			data->buflen += data->values[i] =
+				audit_pack_string(&bufp,
+						  audit_tree_path(krule->tree));
+			break;
+		case AUDIT_FILTERKEY:
+			data->buflen += data->values[i] =
+				audit_pack_string(&bufp, krule->filterkey);
+			break;
+		case AUDIT_EXE:
+			data->buflen += data->values[i] =
+				audit_pack_string(&bufp, audit_mark_path(krule->exe));
+			break;
+		case AUDIT_LOGINUID_SET:
+			if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
+				data->fields[i] = AUDIT_LOGINUID;
+				data->values[i] = AUDIT_UID_UNSET;
+				break;
+			}
+			fallthrough;	/* if set */
+		default:
+			data->values[i] = f->val;
+		}
+	}
+	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
+
+	return data;
+}
+
+/* Compare two rules in kernel format.  Considered success if rules
+ * don't match. */
+static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
+{
+	int i;
+
+	if (a->flags != b->flags ||
+	    a->pflags != b->pflags ||
+	    a->listnr != b->listnr ||
+	    a->action != b->action ||
+	    a->field_count != b->field_count)
+		return 1;
+
+	for (i = 0; i < a->field_count; i++) {
+		if (a->fields[i].type != b->fields[i].type ||
+		    a->fields[i].op != b->fields[i].op)
+			return 1;
+
+		switch(a->fields[i].type) {
+		case AUDIT_SUBJ_USER:
+		case AUDIT_SUBJ_ROLE:
+		case AUDIT_SUBJ_TYPE:
+		case AUDIT_SUBJ_SEN:
+		case AUDIT_SUBJ_CLR:
+		case AUDIT_OBJ_USER:
+		case AUDIT_OBJ_ROLE:
+		case AUDIT_OBJ_TYPE:
+		case AUDIT_OBJ_LEV_LOW:
+		case AUDIT_OBJ_LEV_HIGH:
+			if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
+				return 1;
+			break;
+		case AUDIT_WATCH:
+			if (strcmp(audit_watch_path(a->watch),
+				   audit_watch_path(b->watch)))
+				return 1;
+			break;
+		case AUDIT_DIR:
+			if (strcmp(audit_tree_path(a->tree),
+				   audit_tree_path(b->tree)))
+				return 1;
+			break;
+		case AUDIT_FILTERKEY:
+			/* both filterkeys exist based on above type compare */
+			if (strcmp(a->filterkey, b->filterkey))
+				return 1;
+			break;
+		case AUDIT_EXE:
+			/* both paths exist based on above type compare */
+			if (strcmp(audit_mark_path(a->exe),
+				   audit_mark_path(b->exe)))
+				return 1;
+			break;
+		case AUDIT_UID:
+		case AUDIT_EUID:
+		case AUDIT_SUID:
+		case AUDIT_FSUID:
+		case AUDIT_LOGINUID:
+		case AUDIT_OBJ_UID:
+			if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
+				return 1;
+			break;
+		case AUDIT_GID:
+		case AUDIT_EGID:
+		case AUDIT_SGID:
+		case AUDIT_FSGID:
+		case AUDIT_OBJ_GID:
+			if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
+				return 1;
+			break;
+		default:
+			if (a->fields[i].val != b->fields[i].val)
+				return 1;
+		}
+	}
+
+	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
+		if (a->mask[i] != b->mask[i])
+			return 1;
+
+	return 0;
+}
+
+/* Duplicate LSM field information.  The lsm_rule is opaque, so must be
+ * re-initialized. */
+static inline int audit_dupe_lsm_field(struct audit_field *df,
+					   struct audit_field *sf)
+{
+	int ret = 0;
+	char *lsm_str;
+
+	/* our own copy of lsm_str */
+	lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
+	if (unlikely(!lsm_str))
+		return -ENOMEM;
+	df->lsm_str = lsm_str;
+
+	/* our own (refreshed) copy of lsm_rule */
+	ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
+				       (void **)&df->lsm_rule);
+	/* Keep currently invalid fields around in case they
+	 * become valid after a policy reload. */
+	if (ret == -EINVAL) {
+		pr_warn("audit rule for LSM \'%s\' is invalid\n",
+			df->lsm_str);
+		ret = 0;
+	}
+
+	return ret;
+}
+
+/* Duplicate an audit rule.  This will be a deep copy with the exception
+ * of the watch - that pointer is carried over.  The LSM specific fields
+ * will be updated in the copy.  The point is to be able to replace the old
+ * rule with the new rule in the filterlist, then free the old rule.
+ * The rlist element is undefined; list manipulations are handled apart from
+ * the initial copy. */
+struct audit_entry *audit_dupe_rule(struct audit_krule *old)
+{
+	u32 fcount = old->field_count;
+	struct audit_entry *entry;
+	struct audit_krule *new;
+	char *fk;
+	int i, err = 0;
+
+	entry = audit_init_entry(fcount);
+	if (unlikely(!entry))
+		return ERR_PTR(-ENOMEM);
+
+	new = &entry->rule;
+	new->flags = old->flags;
+	new->pflags = old->pflags;
+	new->listnr = old->listnr;
+	new->action = old->action;
+	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
+		new->mask[i] = old->mask[i];
+	new->prio = old->prio;
+	new->buflen = old->buflen;
+	new->inode_f = old->inode_f;
+	new->field_count = old->field_count;
+
+	/*
+	 * note that we are OK with not refcounting here; audit_match_tree()
+	 * never dereferences tree and we can't get false positives there
+	 * since we'd have to have rule gone from the list *and* removed
+	 * before the chunks found by lookup had been allocated, i.e. before
+	 * the beginning of list scan.
+	 */
+	new->tree = old->tree;
+	memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
+
+	/* deep copy this information, updating the lsm_rule fields, because
+	 * the originals will all be freed when the old rule is freed. */
+	for (i = 0; i < fcount; i++) {
+		switch (new->fields[i].type) {
+		case AUDIT_SUBJ_USER:
+		case AUDIT_SUBJ_ROLE:
+		case AUDIT_SUBJ_TYPE:
+		case AUDIT_SUBJ_SEN:
+		case AUDIT_SUBJ_CLR:
+		case AUDIT_OBJ_USER:
+		case AUDIT_OBJ_ROLE:
+		case AUDIT_OBJ_TYPE:
+		case AUDIT_OBJ_LEV_LOW:
+		case AUDIT_OBJ_LEV_HIGH:
+			err = audit_dupe_lsm_field(&new->fields[i],
+						       &old->fields[i]);
+			break;
+		case AUDIT_FILTERKEY:
+			fk = kstrdup(old->filterkey, GFP_KERNEL);
+			if (unlikely(!fk))
+				err = -ENOMEM;
+			else
+				new->filterkey = fk;
+			break;
+		case AUDIT_EXE:
+			err = audit_dupe_exe(new, old);
+			break;
+		}
+		if (err) {
+			if (new->exe)
+				audit_remove_mark(new->exe);
+			audit_free_rule(entry);
+			return ERR_PTR(err);
+		}
+	}
+
+	if (old->watch) {
+		audit_get_watch(old->watch);
+		new->watch = old->watch;
+	}
+
+	return entry;
+}
+
+/* Find an existing audit rule.
+ * Caller must hold audit_filter_mutex to prevent stale rule data. */
+static struct audit_entry *audit_find_rule(struct audit_entry *entry,
+					   struct list_head **p)
+{
+	struct audit_entry *e, *found = NULL;
+	struct list_head *list;
+	int h;
+
+	if (entry->rule.inode_f) {
+		h = audit_hash_ino(entry->rule.inode_f->val);
+		*p = list = &audit_inode_hash[h];
+	} else if (entry->rule.watch) {
+		/* we don't know the inode number, so must walk entire hash */
+		for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
+			list = &audit_inode_hash[h];
+			list_for_each_entry(e, list, list)
+				if (!audit_compare_rule(&entry->rule, &e->rule)) {
+					found = e;
+					goto out;
+				}
+		}
+		goto out;
+	} else {
+		*p = list = &audit_filter_list[entry->rule.listnr];
+	}
+
+	list_for_each_entry(e, list, list)
+		if (!audit_compare_rule(&entry->rule, &e->rule)) {
+			found = e;
+			goto out;
+		}
+
+out:
+	return found;
+}
+
+static u64 prio_low = ~0ULL/2;
+static u64 prio_high = ~0ULL/2 - 1;
+
+/* Add rule to given filterlist if not a duplicate. */
+static inline int audit_add_rule(struct audit_entry *entry)
+{
+	struct audit_entry *e;
+	struct audit_watch *watch = entry->rule.watch;
+	struct audit_tree *tree = entry->rule.tree;
+	struct list_head *list;
+	int err = 0;
+#ifdef CONFIG_AUDITSYSCALL
+	int dont_count = 0;
+
+	/* If any of these, don't count towards total */
+	switch(entry->rule.listnr) {
+	case AUDIT_FILTER_USER:
+	case AUDIT_FILTER_EXCLUDE:
+	case AUDIT_FILTER_FS:
+		dont_count = 1;
+	}
+#endif
+
+	mutex_lock(&audit_filter_mutex);
+	e = audit_find_rule(entry, &list);
+	if (e) {
+		mutex_unlock(&audit_filter_mutex);
+		err = -EEXIST;
+		/* normally audit_add_tree_rule() will free it on failure */
+		if (tree)
+			audit_put_tree(tree);
+		return err;
+	}
+
+	if (watch) {
+		/* audit_filter_mutex is dropped and re-taken during this call */
+		err = audit_add_watch(&entry->rule, &list);
+		if (err) {
+			mutex_unlock(&audit_filter_mutex);
+			/*
+			 * normally audit_add_tree_rule() will free it
+			 * on failure
+			 */
+			if (tree)
+				audit_put_tree(tree);
+			return err;
+		}
+	}
+	if (tree) {
+		err = audit_add_tree_rule(&entry->rule);
+		if (err) {
+			mutex_unlock(&audit_filter_mutex);
+			return err;
+		}
+	}
+
+	entry->rule.prio = ~0ULL;
+	if (entry->rule.listnr == AUDIT_FILTER_EXIT ||
+	    entry->rule.listnr == AUDIT_FILTER_URING_EXIT) {
+		if (entry->rule.flags & AUDIT_FILTER_PREPEND)
+			entry->rule.prio = ++prio_high;
+		else
+			entry->rule.prio = --prio_low;
+	}
+
+	if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
+		list_add(&entry->rule.list,
+			 &audit_rules_list[entry->rule.listnr]);
+		list_add_rcu(&entry->list, list);
+		entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
+	} else {
+		list_add_tail(&entry->rule.list,
+			      &audit_rules_list[entry->rule.listnr]);
+		list_add_tail_rcu(&entry->list, list);
+	}
+#ifdef CONFIG_AUDITSYSCALL
+	if (!dont_count)
+		audit_n_rules++;
+
+	if (!audit_match_signal(entry))
+		audit_signals++;
+#endif
+	mutex_unlock(&audit_filter_mutex);
+
+	return err;
+}
+
+/* Remove an existing rule from filterlist. */
+int audit_del_rule(struct audit_entry *entry)
+{
+	struct audit_entry  *e;
+	struct audit_tree *tree = entry->rule.tree;
+	struct list_head *list;
+	int ret = 0;
+#ifdef CONFIG_AUDITSYSCALL
+	int dont_count = 0;
+
+	/* If any of these, don't count towards total */
+	switch(entry->rule.listnr) {
+	case AUDIT_FILTER_USER:
+	case AUDIT_FILTER_EXCLUDE:
+	case AUDIT_FILTER_FS:
+		dont_count = 1;
+	}
+#endif
+
+	mutex_lock(&audit_filter_mutex);
+	e = audit_find_rule(entry, &list);
+	if (!e) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	if (e->rule.watch)
+		audit_remove_watch_rule(&e->rule);
+
+	if (e->rule.tree)
+		audit_remove_tree_rule(&e->rule);
+
+	if (e->rule.exe)
+		audit_remove_mark_rule(&e->rule);
+
+#ifdef CONFIG_AUDITSYSCALL
+	if (!dont_count)
+		audit_n_rules--;
+
+	if (!audit_match_signal(entry))
+		audit_signals--;
+#endif
+
+	list_del_rcu(&e->list);
+	list_del(&e->rule.list);
+	call_rcu(&e->rcu, audit_free_rule_rcu);
+
+out:
+	mutex_unlock(&audit_filter_mutex);
+
+	if (tree)
+		audit_put_tree(tree);	/* that's the temporary one */
+
+	return ret;
+}
+
+/* List rules using struct audit_rule_data. */
+static void audit_list_rules(int seq, struct sk_buff_head *q)
+{
+	struct sk_buff *skb;
+	struct audit_krule *r;
+	int i;
+
+	/* This is a blocking read, so use audit_filter_mutex instead of rcu
+	 * iterator to sync with list writers. */
+	for (i=0; i<AUDIT_NR_FILTERS; i++) {
+		list_for_each_entry(r, &audit_rules_list[i], list) {
+			struct audit_rule_data *data;
+
+			data = audit_krule_to_data(r);
+			if (unlikely(!data))
+				break;
+			skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
+					       data,
+					       struct_size(data, buf, data->buflen));
+			if (skb)
+				skb_queue_tail(q, skb);
+			kfree(data);
+		}
+	}
+	skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
+	if (skb)
+		skb_queue_tail(q, skb);
+}
+
+/* Log rule additions and removals */
+static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
+{
+	struct audit_buffer *ab;
+
+	if (!audit_enabled)
+		return;
+
+	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
+	if (!ab)
+		return;
+	audit_log_session_info(ab);
+	audit_log_task_context(ab);
+	audit_log_format(ab, " op=%s", action);
+	audit_log_key(ab, rule->filterkey);
+	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
+	audit_log_end(ab);
+}
+
+/**
+ * audit_rule_change - apply all rules to the specified message type
+ * @type: audit message type
+ * @seq: netlink audit message sequence (serial) number
+ * @data: payload data
+ * @datasz: size of payload data
+ */
+int audit_rule_change(int type, int seq, void *data, size_t datasz)
+{
+	int err = 0;
+	struct audit_entry *entry;
+
+	switch (type) {
+	case AUDIT_ADD_RULE:
+		entry = audit_data_to_entry(data, datasz);
+		if (IS_ERR(entry))
+			return PTR_ERR(entry);
+		err = audit_add_rule(entry);
+		audit_log_rule_change("add_rule", &entry->rule, !err);
+		break;
+	case AUDIT_DEL_RULE:
+		entry = audit_data_to_entry(data, datasz);
+		if (IS_ERR(entry))
+			return PTR_ERR(entry);
+		err = audit_del_rule(entry);
+		audit_log_rule_change("remove_rule", &entry->rule, !err);
+		break;
+	default:
+		WARN_ON(1);
+		return -EINVAL;
+	}
+
+	if (err || type == AUDIT_DEL_RULE) {
+		if (entry->rule.exe)
+			audit_remove_mark(entry->rule.exe);
+		audit_free_rule(entry);
+	}
+
+	return err;
+}
+
+/**
+ * audit_list_rules_send - list the audit rules
+ * @request_skb: skb of request we are replying to (used to target the reply)
+ * @seq: netlink audit message sequence (serial) number
+ */
+int audit_list_rules_send(struct sk_buff *request_skb, int seq)
+{
+	struct task_struct *tsk;
+	struct audit_netlink_list *dest;
+
+	/* We can't just spew out the rules here because we might fill
+	 * the available socket buffer space and deadlock waiting for
+	 * auditctl to read from it... which isn't ever going to
+	 * happen if we're actually running in the context of auditctl
+	 * trying to _send_ the stuff */
+
+	dest = kmalloc(sizeof(*dest), GFP_KERNEL);
+	if (!dest)
+		return -ENOMEM;
+	dest->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
+	dest->portid = NETLINK_CB(request_skb).portid;
+	skb_queue_head_init(&dest->q);
+
+	mutex_lock(&audit_filter_mutex);
+	audit_list_rules(seq, &dest->q);
+	mutex_unlock(&audit_filter_mutex);
+
+	tsk = kthread_run(audit_send_list_thread, dest, "audit_send_list");
+	if (IS_ERR(tsk)) {
+		skb_queue_purge(&dest->q);
+		put_net(dest->net);
+		kfree(dest);
+		return PTR_ERR(tsk);
+	}
+
+	return 0;
+}
+
+int audit_comparator(u32 left, u32 op, u32 right)
+{
+	switch (op) {
+	case Audit_equal:
+		return (left == right);
+	case Audit_not_equal:
+		return (left != right);
+	case Audit_lt:
+		return (left < right);
+	case Audit_le:
+		return (left <= right);
+	case Audit_gt:
+		return (left > right);
+	case Audit_ge:
+		return (left >= right);
+	case Audit_bitmask:
+		return (left & right);
+	case Audit_bittest:
+		return ((left & right) == right);
+	default:
+		return 0;
+	}
+}
+
+int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
+{
+	switch (op) {
+	case Audit_equal:
+		return uid_eq(left, right);
+	case Audit_not_equal:
+		return !uid_eq(left, right);
+	case Audit_lt:
+		return uid_lt(left, right);
+	case Audit_le:
+		return uid_lte(left, right);
+	case Audit_gt:
+		return uid_gt(left, right);
+	case Audit_ge:
+		return uid_gte(left, right);
+	case Audit_bitmask:
+	case Audit_bittest:
+	default:
+		return 0;
+	}
+}
+
+int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
+{
+	switch (op) {
+	case Audit_equal:
+		return gid_eq(left, right);
+	case Audit_not_equal:
+		return !gid_eq(left, right);
+	case Audit_lt:
+		return gid_lt(left, right);
+	case Audit_le:
+		return gid_lte(left, right);
+	case Audit_gt:
+		return gid_gt(left, right);
+	case Audit_ge:
+		return gid_gte(left, right);
+	case Audit_bitmask:
+	case Audit_bittest:
+	default:
+		return 0;
+	}
+}
+
+/**
+ * parent_len - find the length of the parent portion of a pathname
+ * @path: pathname of which to determine length
+ */
+int parent_len(const char *path)
+{
+	int plen;
+	const char *p;
+
+	plen = strlen(path);
+
+	if (plen == 0)
+		return plen;
+
+	/* disregard trailing slashes */
+	p = path + plen - 1;
+	while ((*p == '/') && (p > path))
+		p--;
+
+	/* walk backward until we find the next slash or hit beginning */
+	while ((*p != '/') && (p > path))
+		p--;
+
+	/* did we find a slash? Then increment to include it in path */
+	if (*p == '/')
+		p++;
+
+	return p - path;
+}
+
+/**
+ * audit_compare_dname_path - compare given dentry name with last component in
+ * 			      given path. Return of 0 indicates a match.
+ * @dname:	dentry name that we're comparing
+ * @path:	full pathname that we're comparing
+ * @parentlen:	length of the parent if known. Passing in AUDIT_NAME_FULL
+ * 		here indicates that we must compute this value.
+ */
+int audit_compare_dname_path(const struct qstr *dname, const char *path, int parentlen)
+{
+	int dlen, pathlen;
+	const char *p;
+
+	dlen = dname->len;
+	pathlen = strlen(path);
+	if (pathlen < dlen)
+		return 1;
+
+	parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
+	if (pathlen - parentlen != dlen)
+		return 1;
+
+	p = path + parentlen;
+
+	return strncmp(p, dname->name, dlen);
+}
+
+int audit_filter(int msgtype, unsigned int listtype)
+{
+	struct audit_entry *e;
+	int ret = 1; /* Audit by default */
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
+		int i, result = 0;
+
+		for (i = 0; i < e->rule.field_count; i++) {
+			struct audit_field *f = &e->rule.fields[i];
+			pid_t pid;
+			u32 sid;
+
+			switch (f->type) {
+			case AUDIT_PID:
+				pid = task_pid_nr(current);
+				result = audit_comparator(pid, f->op, f->val);
+				break;
+			case AUDIT_UID:
+				result = audit_uid_comparator(current_uid(), f->op, f->uid);
+				break;
+			case AUDIT_GID:
+				result = audit_gid_comparator(current_gid(), f->op, f->gid);
+				break;
+			case AUDIT_LOGINUID:
+				result = audit_uid_comparator(audit_get_loginuid(current),
+							      f->op, f->uid);
+				break;
+			case AUDIT_LOGINUID_SET:
+				result = audit_comparator(audit_loginuid_set(current),
+							  f->op, f->val);
+				break;
+			case AUDIT_MSGTYPE:
+				result = audit_comparator(msgtype, f->op, f->val);
+				break;
+			case AUDIT_SUBJ_USER:
+			case AUDIT_SUBJ_ROLE:
+			case AUDIT_SUBJ_TYPE:
+			case AUDIT_SUBJ_SEN:
+			case AUDIT_SUBJ_CLR:
+				if (f->lsm_rule) {
+					security_current_getsecid_subj(&sid);
+					result = security_audit_rule_match(sid,
+						   f->type, f->op, f->lsm_rule);
+				}
+				break;
+			case AUDIT_EXE:
+				result = audit_exe_compare(current, e->rule.exe);
+				if (f->op == Audit_not_equal)
+					result = !result;
+				break;
+			default:
+				goto unlock_and_return;
+			}
+			if (result < 0) /* error */
+				goto unlock_and_return;
+			if (!result)
+				break;
+		}
+		if (result > 0) {
+			if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_EXCLUDE)
+				ret = 0;
+			break;
+		}
+	}
+unlock_and_return:
+	rcu_read_unlock();
+	return ret;
+}
+
+static int update_lsm_rule(struct audit_krule *r)
+{
+	struct audit_entry *entry = container_of(r, struct audit_entry, rule);
+	struct audit_entry *nentry;
+	int err = 0;
+
+	if (!security_audit_rule_known(r))
+		return 0;
+
+	nentry = audit_dupe_rule(r);
+	if (entry->rule.exe)
+		audit_remove_mark(entry->rule.exe);
+	if (IS_ERR(nentry)) {
+		/* save the first error encountered for the
+		 * return value */
+		err = PTR_ERR(nentry);
+		audit_panic("error updating LSM filters");
+		if (r->watch)
+			list_del(&r->rlist);
+		list_del_rcu(&entry->list);
+		list_del(&r->list);
+	} else {
+		if (r->watch || r->tree)
+			list_replace_init(&r->rlist, &nentry->rule.rlist);
+		list_replace_rcu(&entry->list, &nentry->list);
+		list_replace(&r->list, &nentry->rule.list);
+	}
+	call_rcu(&entry->rcu, audit_free_rule_rcu);
+
+	return err;
+}
+
+/* This function will re-initialize the lsm_rule field of all applicable rules.
+ * It will traverse the filter lists serarching for rules that contain LSM
+ * specific filter fields.  When such a rule is found, it is copied, the
+ * LSM field is re-initialized, and the old rule is replaced with the
+ * updated rule. */
+int audit_update_lsm_rules(void)
+{
+	struct audit_krule *r, *n;
+	int i, err = 0;
+
+	/* audit_filter_mutex synchronizes the writers */
+	mutex_lock(&audit_filter_mutex);
+
+	for (i = 0; i < AUDIT_NR_FILTERS; i++) {
+		list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
+			int res = update_lsm_rule(r);
+			if (!err)
+				err = res;
+		}
+	}
+	mutex_unlock(&audit_filter_mutex);
+
+	return err;
+}
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
new file mode 100644
index 000000000..c5f41fc75
--- /dev/null
+++ b/kernel/auditsc.c
@@ -0,0 +1,3027 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* auditsc.c -- System-call auditing support
+ * Handles all system-call specific auditing features.
+ *
+ * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
+ * Copyright 2005 Hewlett-Packard Development Company, L.P.
+ * Copyright (C) 2005, 2006 IBM Corporation
+ * All Rights Reserved.
+ *
+ * Written by Rickard E. (Rik) Faith <faith@redhat.com>
+ *
+ * Many of the ideas implemented here are from Stephen C. Tweedie,
+ * especially the idea of avoiding a copy by using getname.
+ *
+ * The method for actual interception of syscall entry and exit (not in
+ * this file -- see entry.S) is based on a GPL'd patch written by
+ * okir@suse.de and Copyright 2003 SuSE Linux AG.
+ *
+ * POSIX message queue support added by George Wilson <ltcgcw@us.ibm.com>,
+ * 2006.
+ *
+ * The support of additional filter rules compares (>, <, >=, <=) was
+ * added by Dustin Kirkland <dustin.kirkland@us.ibm.com>, 2005.
+ *
+ * Modified by Amy Griffis <amy.griffis@hp.com> to collect additional
+ * filesystem information.
+ *
+ * Subject and object context labeling support added by <danjones@us.ibm.com>
+ * and <dustin.kirkland@us.ibm.com> for LSPP certification compliance.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <asm/types.h>
+#include <linux/atomic.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/mm.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/mount.h>
+#include <linux/socket.h>
+#include <linux/mqueue.h>
+#include <linux/audit.h>
+#include <linux/personality.h>
+#include <linux/time.h>
+#include <linux/netlink.h>
+#include <linux/compiler.h>
+#include <asm/unistd.h>
+#include <linux/security.h>
+#include <linux/list.h>
+#include <linux/binfmts.h>
+#include <linux/highmem.h>
+#include <linux/syscalls.h>
+#include <asm/syscall.h>
+#include <linux/capability.h>
+#include <linux/fs_struct.h>
+#include <linux/compat.h>
+#include <linux/ctype.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+#include <linux/fsnotify_backend.h>
+#include <uapi/linux/limits.h>
+#include <uapi/linux/netfilter/nf_tables.h>
+#include <uapi/linux/openat2.h> // struct open_how
+
+#include "audit.h"
+
+/* flags stating the success for a syscall */
+#define AUDITSC_INVALID 0
+#define AUDITSC_SUCCESS 1
+#define AUDITSC_FAILURE 2
+
+/* no execve audit message should be longer than this (userspace limits),
+ * see the note near the top of audit_log_execve_info() about this value */
+#define MAX_EXECVE_AUDIT_LEN 7500
+
+/* max length to print of cmdline/proctitle value during audit */
+#define MAX_PROCTITLE_AUDIT_LEN 128
+
+/* number of audit rules */
+int audit_n_rules;
+
+/* determines whether we collect data for signals sent */
+int audit_signals;
+
+struct audit_aux_data {
+	struct audit_aux_data	*next;
+	int			type;
+};
+
+/* Number of target pids per aux struct. */
+#define AUDIT_AUX_PIDS	16
+
+struct audit_aux_data_pids {
+	struct audit_aux_data	d;
+	pid_t			target_pid[AUDIT_AUX_PIDS];
+	kuid_t			target_auid[AUDIT_AUX_PIDS];
+	kuid_t			target_uid[AUDIT_AUX_PIDS];
+	unsigned int		target_sessionid[AUDIT_AUX_PIDS];
+	u32			target_sid[AUDIT_AUX_PIDS];
+	char 			target_comm[AUDIT_AUX_PIDS][TASK_COMM_LEN];
+	int			pid_count;
+};
+
+struct audit_aux_data_bprm_fcaps {
+	struct audit_aux_data	d;
+	struct audit_cap_data	fcap;
+	unsigned int		fcap_ver;
+	struct audit_cap_data	old_pcap;
+	struct audit_cap_data	new_pcap;
+};
+
+struct audit_tree_refs {
+	struct audit_tree_refs *next;
+	struct audit_chunk *c[31];
+};
+
+struct audit_nfcfgop_tab {
+	enum audit_nfcfgop	op;
+	const char		*s;
+};
+
+static const struct audit_nfcfgop_tab audit_nfcfgs[] = {
+	{ AUDIT_XT_OP_REGISTER,			"xt_register"		   },
+	{ AUDIT_XT_OP_REPLACE,			"xt_replace"		   },
+	{ AUDIT_XT_OP_UNREGISTER,		"xt_unregister"		   },
+	{ AUDIT_NFT_OP_TABLE_REGISTER,		"nft_register_table"	   },
+	{ AUDIT_NFT_OP_TABLE_UNREGISTER,	"nft_unregister_table"	   },
+	{ AUDIT_NFT_OP_CHAIN_REGISTER,		"nft_register_chain"	   },
+	{ AUDIT_NFT_OP_CHAIN_UNREGISTER,	"nft_unregister_chain"	   },
+	{ AUDIT_NFT_OP_RULE_REGISTER,		"nft_register_rule"	   },
+	{ AUDIT_NFT_OP_RULE_UNREGISTER,		"nft_unregister_rule"	   },
+	{ AUDIT_NFT_OP_SET_REGISTER,		"nft_register_set"	   },
+	{ AUDIT_NFT_OP_SET_UNREGISTER,		"nft_unregister_set"	   },
+	{ AUDIT_NFT_OP_SETELEM_REGISTER,	"nft_register_setelem"	   },
+	{ AUDIT_NFT_OP_SETELEM_UNREGISTER,	"nft_unregister_setelem"   },
+	{ AUDIT_NFT_OP_GEN_REGISTER,		"nft_register_gen"	   },
+	{ AUDIT_NFT_OP_OBJ_REGISTER,		"nft_register_obj"	   },
+	{ AUDIT_NFT_OP_OBJ_UNREGISTER,		"nft_unregister_obj"	   },
+	{ AUDIT_NFT_OP_OBJ_RESET,		"nft_reset_obj"		   },
+	{ AUDIT_NFT_OP_FLOWTABLE_REGISTER,	"nft_register_flowtable"   },
+	{ AUDIT_NFT_OP_FLOWTABLE_UNREGISTER,	"nft_unregister_flowtable" },
+	{ AUDIT_NFT_OP_INVALID,			"nft_invalid"		   },
+};
+
+static int audit_match_perm(struct audit_context *ctx, int mask)
+{
+	unsigned n;
+
+	if (unlikely(!ctx))
+		return 0;
+	n = ctx->major;
+
+	switch (audit_classify_syscall(ctx->arch, n)) {
+	case AUDITSC_NATIVE:
+		if ((mask & AUDIT_PERM_WRITE) &&
+		     audit_match_class(AUDIT_CLASS_WRITE, n))
+			return 1;
+		if ((mask & AUDIT_PERM_READ) &&
+		     audit_match_class(AUDIT_CLASS_READ, n))
+			return 1;
+		if ((mask & AUDIT_PERM_ATTR) &&
+		     audit_match_class(AUDIT_CLASS_CHATTR, n))
+			return 1;
+		return 0;
+	case AUDITSC_COMPAT: /* 32bit on biarch */
+		if ((mask & AUDIT_PERM_WRITE) &&
+		     audit_match_class(AUDIT_CLASS_WRITE_32, n))
+			return 1;
+		if ((mask & AUDIT_PERM_READ) &&
+		     audit_match_class(AUDIT_CLASS_READ_32, n))
+			return 1;
+		if ((mask & AUDIT_PERM_ATTR) &&
+		     audit_match_class(AUDIT_CLASS_CHATTR_32, n))
+			return 1;
+		return 0;
+	case AUDITSC_OPEN:
+		return mask & ACC_MODE(ctx->argv[1]);
+	case AUDITSC_OPENAT:
+		return mask & ACC_MODE(ctx->argv[2]);
+	case AUDITSC_SOCKETCALL:
+		return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
+	case AUDITSC_EXECVE:
+		return mask & AUDIT_PERM_EXEC;
+	case AUDITSC_OPENAT2:
+		return mask & ACC_MODE((u32)ctx->openat2.flags);
+	default:
+		return 0;
+	}
+}
+
+static int audit_match_filetype(struct audit_context *ctx, int val)
+{
+	struct audit_names *n;
+	umode_t mode = (umode_t)val;
+
+	if (unlikely(!ctx))
+		return 0;
+
+	list_for_each_entry(n, &ctx->names_list, list) {
+		if ((n->ino != AUDIT_INO_UNSET) &&
+		    ((n->mode & S_IFMT) == mode))
+			return 1;
+	}
+
+	return 0;
+}
+
+/*
+ * We keep a linked list of fixed-sized (31 pointer) arrays of audit_chunk *;
+ * ->first_trees points to its beginning, ->trees - to the current end of data.
+ * ->tree_count is the number of free entries in array pointed to by ->trees.
+ * Original condition is (NULL, NULL, 0); as soon as it grows we never revert to NULL,
+ * "empty" becomes (p, p, 31) afterwards.  We don't shrink the list (and seriously,
+ * it's going to remain 1-element for almost any setup) until we free context itself.
+ * References in it _are_ dropped - at the same time we free/drop aux stuff.
+ */
+
+static void audit_set_auditable(struct audit_context *ctx)
+{
+	if (!ctx->prio) {
+		ctx->prio = 1;
+		ctx->current_state = AUDIT_STATE_RECORD;
+	}
+}
+
+static int put_tree_ref(struct audit_context *ctx, struct audit_chunk *chunk)
+{
+	struct audit_tree_refs *p = ctx->trees;
+	int left = ctx->tree_count;
+
+	if (likely(left)) {
+		p->c[--left] = chunk;
+		ctx->tree_count = left;
+		return 1;
+	}
+	if (!p)
+		return 0;
+	p = p->next;
+	if (p) {
+		p->c[30] = chunk;
+		ctx->trees = p;
+		ctx->tree_count = 30;
+		return 1;
+	}
+	return 0;
+}
+
+static int grow_tree_refs(struct audit_context *ctx)
+{
+	struct audit_tree_refs *p = ctx->trees;
+
+	ctx->trees = kzalloc(sizeof(struct audit_tree_refs), GFP_KERNEL);
+	if (!ctx->trees) {
+		ctx->trees = p;
+		return 0;
+	}
+	if (p)
+		p->next = ctx->trees;
+	else
+		ctx->first_trees = ctx->trees;
+	ctx->tree_count = 31;
+	return 1;
+}
+
+static void unroll_tree_refs(struct audit_context *ctx,
+		      struct audit_tree_refs *p, int count)
+{
+	struct audit_tree_refs *q;
+	int n;
+
+	if (!p) {
+		/* we started with empty chain */
+		p = ctx->first_trees;
+		count = 31;
+		/* if the very first allocation has failed, nothing to do */
+		if (!p)
+			return;
+	}
+	n = count;
+	for (q = p; q != ctx->trees; q = q->next, n = 31) {
+		while (n--) {
+			audit_put_chunk(q->c[n]);
+			q->c[n] = NULL;
+		}
+	}
+	while (n-- > ctx->tree_count) {
+		audit_put_chunk(q->c[n]);
+		q->c[n] = NULL;
+	}
+	ctx->trees = p;
+	ctx->tree_count = count;
+}
+
+static void free_tree_refs(struct audit_context *ctx)
+{
+	struct audit_tree_refs *p, *q;
+
+	for (p = ctx->first_trees; p; p = q) {
+		q = p->next;
+		kfree(p);
+	}
+}
+
+static int match_tree_refs(struct audit_context *ctx, struct audit_tree *tree)
+{
+	struct audit_tree_refs *p;
+	int n;
+
+	if (!tree)
+		return 0;
+	/* full ones */
+	for (p = ctx->first_trees; p != ctx->trees; p = p->next) {
+		for (n = 0; n < 31; n++)
+			if (audit_tree_match(p->c[n], tree))
+				return 1;
+	}
+	/* partial */
+	if (p) {
+		for (n = ctx->tree_count; n < 31; n++)
+			if (audit_tree_match(p->c[n], tree))
+				return 1;
+	}
+	return 0;
+}
+
+static int audit_compare_uid(kuid_t uid,
+			     struct audit_names *name,
+			     struct audit_field *f,
+			     struct audit_context *ctx)
+{
+	struct audit_names *n;
+	int rc;
+
+	if (name) {
+		rc = audit_uid_comparator(uid, f->op, name->uid);
+		if (rc)
+			return rc;
+	}
+
+	if (ctx) {
+		list_for_each_entry(n, &ctx->names_list, list) {
+			rc = audit_uid_comparator(uid, f->op, n->uid);
+			if (rc)
+				return rc;
+		}
+	}
+	return 0;
+}
+
+static int audit_compare_gid(kgid_t gid,
+			     struct audit_names *name,
+			     struct audit_field *f,
+			     struct audit_context *ctx)
+{
+	struct audit_names *n;
+	int rc;
+
+	if (name) {
+		rc = audit_gid_comparator(gid, f->op, name->gid);
+		if (rc)
+			return rc;
+	}
+
+	if (ctx) {
+		list_for_each_entry(n, &ctx->names_list, list) {
+			rc = audit_gid_comparator(gid, f->op, n->gid);
+			if (rc)
+				return rc;
+		}
+	}
+	return 0;
+}
+
+static int audit_field_compare(struct task_struct *tsk,
+			       const struct cred *cred,
+			       struct audit_field *f,
+			       struct audit_context *ctx,
+			       struct audit_names *name)
+{
+	switch (f->val) {
+	/* process to file object comparisons */
+	case AUDIT_COMPARE_UID_TO_OBJ_UID:
+		return audit_compare_uid(cred->uid, name, f, ctx);
+	case AUDIT_COMPARE_GID_TO_OBJ_GID:
+		return audit_compare_gid(cred->gid, name, f, ctx);
+	case AUDIT_COMPARE_EUID_TO_OBJ_UID:
+		return audit_compare_uid(cred->euid, name, f, ctx);
+	case AUDIT_COMPARE_EGID_TO_OBJ_GID:
+		return audit_compare_gid(cred->egid, name, f, ctx);
+	case AUDIT_COMPARE_AUID_TO_OBJ_UID:
+		return audit_compare_uid(audit_get_loginuid(tsk), name, f, ctx);
+	case AUDIT_COMPARE_SUID_TO_OBJ_UID:
+		return audit_compare_uid(cred->suid, name, f, ctx);
+	case AUDIT_COMPARE_SGID_TO_OBJ_GID:
+		return audit_compare_gid(cred->sgid, name, f, ctx);
+	case AUDIT_COMPARE_FSUID_TO_OBJ_UID:
+		return audit_compare_uid(cred->fsuid, name, f, ctx);
+	case AUDIT_COMPARE_FSGID_TO_OBJ_GID:
+		return audit_compare_gid(cred->fsgid, name, f, ctx);
+	/* uid comparisons */
+	case AUDIT_COMPARE_UID_TO_AUID:
+		return audit_uid_comparator(cred->uid, f->op,
+					    audit_get_loginuid(tsk));
+	case AUDIT_COMPARE_UID_TO_EUID:
+		return audit_uid_comparator(cred->uid, f->op, cred->euid);
+	case AUDIT_COMPARE_UID_TO_SUID:
+		return audit_uid_comparator(cred->uid, f->op, cred->suid);
+	case AUDIT_COMPARE_UID_TO_FSUID:
+		return audit_uid_comparator(cred->uid, f->op, cred->fsuid);
+	/* auid comparisons */
+	case AUDIT_COMPARE_AUID_TO_EUID:
+		return audit_uid_comparator(audit_get_loginuid(tsk), f->op,
+					    cred->euid);
+	case AUDIT_COMPARE_AUID_TO_SUID:
+		return audit_uid_comparator(audit_get_loginuid(tsk), f->op,
+					    cred->suid);
+	case AUDIT_COMPARE_AUID_TO_FSUID:
+		return audit_uid_comparator(audit_get_loginuid(tsk), f->op,
+					    cred->fsuid);
+	/* euid comparisons */
+	case AUDIT_COMPARE_EUID_TO_SUID:
+		return audit_uid_comparator(cred->euid, f->op, cred->suid);
+	case AUDIT_COMPARE_EUID_TO_FSUID:
+		return audit_uid_comparator(cred->euid, f->op, cred->fsuid);
+	/* suid comparisons */
+	case AUDIT_COMPARE_SUID_TO_FSUID:
+		return audit_uid_comparator(cred->suid, f->op, cred->fsuid);
+	/* gid comparisons */
+	case AUDIT_COMPARE_GID_TO_EGID:
+		return audit_gid_comparator(cred->gid, f->op, cred->egid);
+	case AUDIT_COMPARE_GID_TO_SGID:
+		return audit_gid_comparator(cred->gid, f->op, cred->sgid);
+	case AUDIT_COMPARE_GID_TO_FSGID:
+		return audit_gid_comparator(cred->gid, f->op, cred->fsgid);
+	/* egid comparisons */
+	case AUDIT_COMPARE_EGID_TO_SGID:
+		return audit_gid_comparator(cred->egid, f->op, cred->sgid);
+	case AUDIT_COMPARE_EGID_TO_FSGID:
+		return audit_gid_comparator(cred->egid, f->op, cred->fsgid);
+	/* sgid comparison */
+	case AUDIT_COMPARE_SGID_TO_FSGID:
+		return audit_gid_comparator(cred->sgid, f->op, cred->fsgid);
+	default:
+		WARN(1, "Missing AUDIT_COMPARE define.  Report as a bug\n");
+		return 0;
+	}
+	return 0;
+}
+
+/* Determine if any context name data matches a rule's watch data */
+/* Compare a task_struct with an audit_rule.  Return 1 on match, 0
+ * otherwise.
+ *
+ * If task_creation is true, this is an explicit indication that we are
+ * filtering a task rule at task creation time.  This and tsk == current are
+ * the only situations where tsk->cred may be accessed without an rcu read lock.
+ */
+static int audit_filter_rules(struct task_struct *tsk,
+			      struct audit_krule *rule,
+			      struct audit_context *ctx,
+			      struct audit_names *name,
+			      enum audit_state *state,
+			      bool task_creation)
+{
+	const struct cred *cred;
+	int i, need_sid = 1;
+	u32 sid;
+	unsigned int sessionid;
+
+	if (ctx && rule->prio <= ctx->prio)
+		return 0;
+
+	cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
+
+	for (i = 0; i < rule->field_count; i++) {
+		struct audit_field *f = &rule->fields[i];
+		struct audit_names *n;
+		int result = 0;
+		pid_t pid;
+
+		switch (f->type) {
+		case AUDIT_PID:
+			pid = task_tgid_nr(tsk);
+			result = audit_comparator(pid, f->op, f->val);
+			break;
+		case AUDIT_PPID:
+			if (ctx) {
+				if (!ctx->ppid)
+					ctx->ppid = task_ppid_nr(tsk);
+				result = audit_comparator(ctx->ppid, f->op, f->val);
+			}
+			break;
+		case AUDIT_EXE:
+			result = audit_exe_compare(tsk, rule->exe);
+			if (f->op == Audit_not_equal)
+				result = !result;
+			break;
+		case AUDIT_UID:
+			result = audit_uid_comparator(cred->uid, f->op, f->uid);
+			break;
+		case AUDIT_EUID:
+			result = audit_uid_comparator(cred->euid, f->op, f->uid);
+			break;
+		case AUDIT_SUID:
+			result = audit_uid_comparator(cred->suid, f->op, f->uid);
+			break;
+		case AUDIT_FSUID:
+			result = audit_uid_comparator(cred->fsuid, f->op, f->uid);
+			break;
+		case AUDIT_GID:
+			result = audit_gid_comparator(cred->gid, f->op, f->gid);
+			if (f->op == Audit_equal) {
+				if (!result)
+					result = groups_search(cred->group_info, f->gid);
+			} else if (f->op == Audit_not_equal) {
+				if (result)
+					result = !groups_search(cred->group_info, f->gid);
+			}
+			break;
+		case AUDIT_EGID:
+			result = audit_gid_comparator(cred->egid, f->op, f->gid);
+			if (f->op == Audit_equal) {
+				if (!result)
+					result = groups_search(cred->group_info, f->gid);
+			} else if (f->op == Audit_not_equal) {
+				if (result)
+					result = !groups_search(cred->group_info, f->gid);
+			}
+			break;
+		case AUDIT_SGID:
+			result = audit_gid_comparator(cred->sgid, f->op, f->gid);
+			break;
+		case AUDIT_FSGID:
+			result = audit_gid_comparator(cred->fsgid, f->op, f->gid);
+			break;
+		case AUDIT_SESSIONID:
+			sessionid = audit_get_sessionid(tsk);
+			result = audit_comparator(sessionid, f->op, f->val);
+			break;
+		case AUDIT_PERS:
+			result = audit_comparator(tsk->personality, f->op, f->val);
+			break;
+		case AUDIT_ARCH:
+			if (ctx)
+				result = audit_comparator(ctx->arch, f->op, f->val);
+			break;
+
+		case AUDIT_EXIT:
+			if (ctx && ctx->return_valid != AUDITSC_INVALID)
+				result = audit_comparator(ctx->return_code, f->op, f->val);
+			break;
+		case AUDIT_SUCCESS:
+			if (ctx && ctx->return_valid != AUDITSC_INVALID) {
+				if (f->val)
+					result = audit_comparator(ctx->return_valid, f->op, AUDITSC_SUCCESS);
+				else
+					result = audit_comparator(ctx->return_valid, f->op, AUDITSC_FAILURE);
+			}
+			break;
+		case AUDIT_DEVMAJOR:
+			if (name) {
+				if (audit_comparator(MAJOR(name->dev), f->op, f->val) ||
+				    audit_comparator(MAJOR(name->rdev), f->op, f->val))
+					++result;
+			} else if (ctx) {
+				list_for_each_entry(n, &ctx->names_list, list) {
+					if (audit_comparator(MAJOR(n->dev), f->op, f->val) ||
+					    audit_comparator(MAJOR(n->rdev), f->op, f->val)) {
+						++result;
+						break;
+					}
+				}
+			}
+			break;
+		case AUDIT_DEVMINOR:
+			if (name) {
+				if (audit_comparator(MINOR(name->dev), f->op, f->val) ||
+				    audit_comparator(MINOR(name->rdev), f->op, f->val))
+					++result;
+			} else if (ctx) {
+				list_for_each_entry(n, &ctx->names_list, list) {
+					if (audit_comparator(MINOR(n->dev), f->op, f->val) ||
+					    audit_comparator(MINOR(n->rdev), f->op, f->val)) {
+						++result;
+						break;
+					}
+				}
+			}
+			break;
+		case AUDIT_INODE:
+			if (name)
+				result = audit_comparator(name->ino, f->op, f->val);
+			else if (ctx) {
+				list_for_each_entry(n, &ctx->names_list, list) {
+					if (audit_comparator(n->ino, f->op, f->val)) {
+						++result;
+						break;
+					}
+				}
+			}
+			break;
+		case AUDIT_OBJ_UID:
+			if (name) {
+				result = audit_uid_comparator(name->uid, f->op, f->uid);
+			} else if (ctx) {
+				list_for_each_entry(n, &ctx->names_list, list) {
+					if (audit_uid_comparator(n->uid, f->op, f->uid)) {
+						++result;
+						break;
+					}
+				}
+			}
+			break;
+		case AUDIT_OBJ_GID:
+			if (name) {
+				result = audit_gid_comparator(name->gid, f->op, f->gid);
+			} else if (ctx) {
+				list_for_each_entry(n, &ctx->names_list, list) {
+					if (audit_gid_comparator(n->gid, f->op, f->gid)) {
+						++result;
+						break;
+					}
+				}
+			}
+			break;
+		case AUDIT_WATCH:
+			if (name) {
+				result = audit_watch_compare(rule->watch,
+							     name->ino,
+							     name->dev);
+				if (f->op == Audit_not_equal)
+					result = !result;
+			}
+			break;
+		case AUDIT_DIR:
+			if (ctx) {
+				result = match_tree_refs(ctx, rule->tree);
+				if (f->op == Audit_not_equal)
+					result = !result;
+			}
+			break;
+		case AUDIT_LOGINUID:
+			result = audit_uid_comparator(audit_get_loginuid(tsk),
+						      f->op, f->uid);
+			break;
+		case AUDIT_LOGINUID_SET:
+			result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val);
+			break;
+		case AUDIT_SADDR_FAM:
+			if (ctx && ctx->sockaddr)
+				result = audit_comparator(ctx->sockaddr->ss_family,
+							  f->op, f->val);
+			break;
+		case AUDIT_SUBJ_USER:
+		case AUDIT_SUBJ_ROLE:
+		case AUDIT_SUBJ_TYPE:
+		case AUDIT_SUBJ_SEN:
+		case AUDIT_SUBJ_CLR:
+			/* NOTE: this may return negative values indicating
+			   a temporary error.  We simply treat this as a
+			   match for now to avoid losing information that
+			   may be wanted.   An error message will also be
+			   logged upon error */
+			if (f->lsm_rule) {
+				if (need_sid) {
+					/* @tsk should always be equal to
+					 * @current with the exception of
+					 * fork()/copy_process() in which case
+					 * the new @tsk creds are still a dup
+					 * of @current's creds so we can still
+					 * use security_current_getsecid_subj()
+					 * here even though it always refs
+					 * @current's creds
+					 */
+					security_current_getsecid_subj(&sid);
+					need_sid = 0;
+				}
+				result = security_audit_rule_match(sid, f->type,
+								   f->op,
+								   f->lsm_rule);
+			}
+			break;
+		case AUDIT_OBJ_USER:
+		case AUDIT_OBJ_ROLE:
+		case AUDIT_OBJ_TYPE:
+		case AUDIT_OBJ_LEV_LOW:
+		case AUDIT_OBJ_LEV_HIGH:
+			/* The above note for AUDIT_SUBJ_USER...AUDIT_SUBJ_CLR
+			   also applies here */
+			if (f->lsm_rule) {
+				/* Find files that match */
+				if (name) {
+					result = security_audit_rule_match(
+								name->osid,
+								f->type,
+								f->op,
+								f->lsm_rule);
+				} else if (ctx) {
+					list_for_each_entry(n, &ctx->names_list, list) {
+						if (security_audit_rule_match(
+								n->osid,
+								f->type,
+								f->op,
+								f->lsm_rule)) {
+							++result;
+							break;
+						}
+					}
+				}
+				/* Find ipc objects that match */
+				if (!ctx || ctx->type != AUDIT_IPC)
+					break;
+				if (security_audit_rule_match(ctx->ipc.osid,
+							      f->type, f->op,
+							      f->lsm_rule))
+					++result;
+			}
+			break;
+		case AUDIT_ARG0:
+		case AUDIT_ARG1:
+		case AUDIT_ARG2:
+		case AUDIT_ARG3:
+			if (ctx)
+				result = audit_comparator(ctx->argv[f->type-AUDIT_ARG0], f->op, f->val);
+			break;
+		case AUDIT_FILTERKEY:
+			/* ignore this field for filtering */
+			result = 1;
+			break;
+		case AUDIT_PERM:
+			result = audit_match_perm(ctx, f->val);
+			if (f->op == Audit_not_equal)
+				result = !result;
+			break;
+		case AUDIT_FILETYPE:
+			result = audit_match_filetype(ctx, f->val);
+			if (f->op == Audit_not_equal)
+				result = !result;
+			break;
+		case AUDIT_FIELD_COMPARE:
+			result = audit_field_compare(tsk, cred, f, ctx, name);
+			break;
+		}
+		if (!result)
+			return 0;
+	}
+
+	if (ctx) {
+		if (rule->filterkey) {
+			kfree(ctx->filterkey);
+			ctx->filterkey = kstrdup(rule->filterkey, GFP_ATOMIC);
+		}
+		ctx->prio = rule->prio;
+	}
+	switch (rule->action) {
+	case AUDIT_NEVER:
+		*state = AUDIT_STATE_DISABLED;
+		break;
+	case AUDIT_ALWAYS:
+		*state = AUDIT_STATE_RECORD;
+		break;
+	}
+	return 1;
+}
+
+/* At process creation time, we can determine if system-call auditing is
+ * completely disabled for this task.  Since we only have the task
+ * structure at this point, we can only check uid and gid.
+ */
+static enum audit_state audit_filter_task(struct task_struct *tsk, char **key)
+{
+	struct audit_entry *e;
+	enum audit_state   state;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TASK], list) {
+		if (audit_filter_rules(tsk, &e->rule, NULL, NULL,
+				       &state, true)) {
+			if (state == AUDIT_STATE_RECORD)
+				*key = kstrdup(e->rule.filterkey, GFP_ATOMIC);
+			rcu_read_unlock();
+			return state;
+		}
+	}
+	rcu_read_unlock();
+	return AUDIT_STATE_BUILD;
+}
+
+static int audit_in_mask(const struct audit_krule *rule, unsigned long val)
+{
+	int word, bit;
+
+	if (val > 0xffffffff)
+		return false;
+
+	word = AUDIT_WORD(val);
+	if (word >= AUDIT_BITMASK_SIZE)
+		return false;
+
+	bit = AUDIT_BIT(val);
+
+	return rule->mask[word] & bit;
+}
+
+/**
+ * audit_filter_uring - apply filters to an io_uring operation
+ * @tsk: associated task
+ * @ctx: audit context
+ */
+static void audit_filter_uring(struct task_struct *tsk,
+			       struct audit_context *ctx)
+{
+	struct audit_entry *e;
+	enum audit_state state;
+
+	if (auditd_test_task(tsk))
+		return;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_URING_EXIT],
+				list) {
+		if (audit_in_mask(&e->rule, ctx->uring_op) &&
+		    audit_filter_rules(tsk, &e->rule, ctx, NULL, &state,
+				       false)) {
+			rcu_read_unlock();
+			ctx->current_state = state;
+			return;
+		}
+	}
+	rcu_read_unlock();
+}
+
+/* At syscall exit time, this filter is called if the audit_state is
+ * not low enough that auditing cannot take place, but is also not
+ * high enough that we already know we have to write an audit record
+ * (i.e., the state is AUDIT_STATE_BUILD).
+ */
+static void audit_filter_syscall(struct task_struct *tsk,
+				 struct audit_context *ctx)
+{
+	struct audit_entry *e;
+	enum audit_state state;
+
+	if (auditd_test_task(tsk))
+		return;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_EXIT], list) {
+		if (audit_in_mask(&e->rule, ctx->major) &&
+		    audit_filter_rules(tsk, &e->rule, ctx, NULL,
+				       &state, false)) {
+			rcu_read_unlock();
+			ctx->current_state = state;
+			return;
+		}
+	}
+	rcu_read_unlock();
+	return;
+}
+
+/*
+ * Given an audit_name check the inode hash table to see if they match.
+ * Called holding the rcu read lock to protect the use of audit_inode_hash
+ */
+static int audit_filter_inode_name(struct task_struct *tsk,
+				   struct audit_names *n,
+				   struct audit_context *ctx) {
+	int h = audit_hash_ino((u32)n->ino);
+	struct list_head *list = &audit_inode_hash[h];
+	struct audit_entry *e;
+	enum audit_state state;
+
+	list_for_each_entry_rcu(e, list, list) {
+		if (audit_in_mask(&e->rule, ctx->major) &&
+		    audit_filter_rules(tsk, &e->rule, ctx, n, &state, false)) {
+			ctx->current_state = state;
+			return 1;
+		}
+	}
+	return 0;
+}
+
+/* At syscall exit time, this filter is called if any audit_names have been
+ * collected during syscall processing.  We only check rules in sublists at hash
+ * buckets applicable to the inode numbers in audit_names.
+ * Regarding audit_state, same rules apply as for audit_filter_syscall().
+ */
+void audit_filter_inodes(struct task_struct *tsk, struct audit_context *ctx)
+{
+	struct audit_names *n;
+
+	if (auditd_test_task(tsk))
+		return;
+
+	rcu_read_lock();
+
+	list_for_each_entry(n, &ctx->names_list, list) {
+		if (audit_filter_inode_name(tsk, n, ctx))
+			break;
+	}
+	rcu_read_unlock();
+}
+
+static inline void audit_proctitle_free(struct audit_context *context)
+{
+	kfree(context->proctitle.value);
+	context->proctitle.value = NULL;
+	context->proctitle.len = 0;
+}
+
+static inline void audit_free_module(struct audit_context *context)
+{
+	if (context->type == AUDIT_KERN_MODULE) {
+		kfree(context->module.name);
+		context->module.name = NULL;
+	}
+}
+static inline void audit_free_names(struct audit_context *context)
+{
+	struct audit_names *n, *next;
+
+	list_for_each_entry_safe(n, next, &context->names_list, list) {
+		list_del(&n->list);
+		if (n->name)
+			putname(n->name);
+		if (n->should_free)
+			kfree(n);
+	}
+	context->name_count = 0;
+	path_put(&context->pwd);
+	context->pwd.dentry = NULL;
+	context->pwd.mnt = NULL;
+}
+
+static inline void audit_free_aux(struct audit_context *context)
+{
+	struct audit_aux_data *aux;
+
+	while ((aux = context->aux)) {
+		context->aux = aux->next;
+		kfree(aux);
+	}
+	context->aux = NULL;
+	while ((aux = context->aux_pids)) {
+		context->aux_pids = aux->next;
+		kfree(aux);
+	}
+	context->aux_pids = NULL;
+}
+
+/**
+ * audit_reset_context - reset a audit_context structure
+ * @ctx: the audit_context to reset
+ *
+ * All fields in the audit_context will be reset to an initial state, all
+ * references held by fields will be dropped, and private memory will be
+ * released.  When this function returns the audit_context will be suitable
+ * for reuse, so long as the passed context is not NULL or a dummy context.
+ */
+static void audit_reset_context(struct audit_context *ctx)
+{
+	if (!ctx)
+		return;
+
+	/* if ctx is non-null, reset the "ctx->context" regardless */
+	ctx->context = AUDIT_CTX_UNUSED;
+	if (ctx->dummy)
+		return;
+
+	/*
+	 * NOTE: It shouldn't matter in what order we release the fields, so
+	 *       release them in the order in which they appear in the struct;
+	 *       this gives us some hope of quickly making sure we are
+	 *       resetting the audit_context properly.
+	 *
+	 *       Other things worth mentioning:
+	 *       - we don't reset "dummy"
+	 *       - we don't reset "state", we do reset "current_state"
+	 *       - we preserve "filterkey" if "state" is AUDIT_STATE_RECORD
+	 *       - much of this is likely overkill, but play it safe for now
+	 *       - we really need to work on improving the audit_context struct
+	 */
+
+	ctx->current_state = ctx->state;
+	ctx->serial = 0;
+	ctx->major = 0;
+	ctx->uring_op = 0;
+	ctx->ctime = (struct timespec64){ .tv_sec = 0, .tv_nsec = 0 };
+	memset(ctx->argv, 0, sizeof(ctx->argv));
+	ctx->return_code = 0;
+	ctx->prio = (ctx->state == AUDIT_STATE_RECORD ? ~0ULL : 0);
+	ctx->return_valid = AUDITSC_INVALID;
+	audit_free_names(ctx);
+	if (ctx->state != AUDIT_STATE_RECORD) {
+		kfree(ctx->filterkey);
+		ctx->filterkey = NULL;
+	}
+	audit_free_aux(ctx);
+	kfree(ctx->sockaddr);
+	ctx->sockaddr = NULL;
+	ctx->sockaddr_len = 0;
+	ctx->ppid = 0;
+	ctx->uid = ctx->euid = ctx->suid = ctx->fsuid = KUIDT_INIT(0);
+	ctx->gid = ctx->egid = ctx->sgid = ctx->fsgid = KGIDT_INIT(0);
+	ctx->personality = 0;
+	ctx->arch = 0;
+	ctx->target_pid = 0;
+	ctx->target_auid = ctx->target_uid = KUIDT_INIT(0);
+	ctx->target_sessionid = 0;
+	ctx->target_sid = 0;
+	ctx->target_comm[0] = '\0';
+	unroll_tree_refs(ctx, NULL, 0);
+	WARN_ON(!list_empty(&ctx->killed_trees));
+	audit_free_module(ctx);
+	ctx->fds[0] = -1;
+	ctx->type = 0; /* reset last for audit_free_*() */
+}
+
+static inline struct audit_context *audit_alloc_context(enum audit_state state)
+{
+	struct audit_context *context;
+
+	context = kzalloc(sizeof(*context), GFP_KERNEL);
+	if (!context)
+		return NULL;
+	context->context = AUDIT_CTX_UNUSED;
+	context->state = state;
+	context->prio = state == AUDIT_STATE_RECORD ? ~0ULL : 0;
+	INIT_LIST_HEAD(&context->killed_trees);
+	INIT_LIST_HEAD(&context->names_list);
+	context->fds[0] = -1;
+	context->return_valid = AUDITSC_INVALID;
+	return context;
+}
+
+/**
+ * audit_alloc - allocate an audit context block for a task
+ * @tsk: task
+ *
+ * Filter on the task information and allocate a per-task audit context
+ * if necessary.  Doing so turns on system call auditing for the
+ * specified task.  This is called from copy_process, so no lock is
+ * needed.
+ */
+int audit_alloc(struct task_struct *tsk)
+{
+	struct audit_context *context;
+	enum audit_state     state;
+	char *key = NULL;
+
+	if (likely(!audit_ever_enabled))
+		return 0;
+
+	state = audit_filter_task(tsk, &key);
+	if (state == AUDIT_STATE_DISABLED) {
+		clear_task_syscall_work(tsk, SYSCALL_AUDIT);
+		return 0;
+	}
+
+	if (!(context = audit_alloc_context(state))) {
+		kfree(key);
+		audit_log_lost("out of memory in audit_alloc");
+		return -ENOMEM;
+	}
+	context->filterkey = key;
+
+	audit_set_context(tsk, context);
+	set_task_syscall_work(tsk, SYSCALL_AUDIT);
+	return 0;
+}
+
+static inline void audit_free_context(struct audit_context *context)
+{
+	/* resetting is extra work, but it is likely just noise */
+	audit_reset_context(context);
+	audit_proctitle_free(context);
+	free_tree_refs(context);
+	kfree(context->filterkey);
+	kfree(context);
+}
+
+static int audit_log_pid_context(struct audit_context *context, pid_t pid,
+				 kuid_t auid, kuid_t uid, unsigned int sessionid,
+				 u32 sid, char *comm)
+{
+	struct audit_buffer *ab;
+	char *ctx = NULL;
+	u32 len;
+	int rc = 0;
+
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
+	if (!ab)
+		return rc;
+
+	audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid,
+			 from_kuid(&init_user_ns, auid),
+			 from_kuid(&init_user_ns, uid), sessionid);
+	if (sid) {
+		if (security_secid_to_secctx(sid, &ctx, &len)) {
+			audit_log_format(ab, " obj=(none)");
+			rc = 1;
+		} else {
+			audit_log_format(ab, " obj=%s", ctx);
+			security_release_secctx(ctx, len);
+		}
+	}
+	audit_log_format(ab, " ocomm=");
+	audit_log_untrustedstring(ab, comm);
+	audit_log_end(ab);
+
+	return rc;
+}
+
+static void audit_log_execve_info(struct audit_context *context,
+				  struct audit_buffer **ab)
+{
+	long len_max;
+	long len_rem;
+	long len_full;
+	long len_buf;
+	long len_abuf = 0;
+	long len_tmp;
+	bool require_data;
+	bool encode;
+	unsigned int iter;
+	unsigned int arg;
+	char *buf_head;
+	char *buf;
+	const char __user *p = (const char __user *)current->mm->arg_start;
+
+	/* NOTE: this buffer needs to be large enough to hold all the non-arg
+	 *       data we put in the audit record for this argument (see the
+	 *       code below) ... at this point in time 96 is plenty */
+	char abuf[96];
+
+	/* NOTE: we set MAX_EXECVE_AUDIT_LEN to a rather arbitrary limit, the
+	 *       current value of 7500 is not as important as the fact that it
+	 *       is less than 8k, a setting of 7500 gives us plenty of wiggle
+	 *       room if we go over a little bit in the logging below */
+	WARN_ON_ONCE(MAX_EXECVE_AUDIT_LEN > 7500);
+	len_max = MAX_EXECVE_AUDIT_LEN;
+
+	/* scratch buffer to hold the userspace args */
+	buf_head = kmalloc(MAX_EXECVE_AUDIT_LEN + 1, GFP_KERNEL);
+	if (!buf_head) {
+		audit_panic("out of memory for argv string");
+		return;
+	}
+	buf = buf_head;
+
+	audit_log_format(*ab, "argc=%d", context->execve.argc);
+
+	len_rem = len_max;
+	len_buf = 0;
+	len_full = 0;
+	require_data = true;
+	encode = false;
+	iter = 0;
+	arg = 0;
+	do {
+		/* NOTE: we don't ever want to trust this value for anything
+		 *       serious, but the audit record format insists we
+		 *       provide an argument length for really long arguments,
+		 *       e.g. > MAX_EXECVE_AUDIT_LEN, so we have no choice but
+		 *       to use strncpy_from_user() to obtain this value for
+		 *       recording in the log, although we don't use it
+		 *       anywhere here to avoid a double-fetch problem */
+		if (len_full == 0)
+			len_full = strnlen_user(p, MAX_ARG_STRLEN) - 1;
+
+		/* read more data from userspace */
+		if (require_data) {
+			/* can we make more room in the buffer? */
+			if (buf != buf_head) {
+				memmove(buf_head, buf, len_buf);
+				buf = buf_head;
+			}
+
+			/* fetch as much as we can of the argument */
+			len_tmp = strncpy_from_user(&buf_head[len_buf], p,
+						    len_max - len_buf);
+			if (len_tmp == -EFAULT) {
+				/* unable to copy from userspace */
+				send_sig(SIGKILL, current, 0);
+				goto out;
+			} else if (len_tmp == (len_max - len_buf)) {
+				/* buffer is not large enough */
+				require_data = true;
+				/* NOTE: if we are going to span multiple
+				 *       buffers force the encoding so we stand
+				 *       a chance at a sane len_full value and
+				 *       consistent record encoding */
+				encode = true;
+				len_full = len_full * 2;
+				p += len_tmp;
+			} else {
+				require_data = false;
+				if (!encode)
+					encode = audit_string_contains_control(
+								buf, len_tmp);
+				/* try to use a trusted value for len_full */
+				if (len_full < len_max)
+					len_full = (encode ?
+						    len_tmp * 2 : len_tmp);
+				p += len_tmp + 1;
+			}
+			len_buf += len_tmp;
+			buf_head[len_buf] = '\0';
+
+			/* length of the buffer in the audit record? */
+			len_abuf = (encode ? len_buf * 2 : len_buf + 2);
+		}
+
+		/* write as much as we can to the audit log */
+		if (len_buf >= 0) {
+			/* NOTE: some magic numbers here - basically if we
+			 *       can't fit a reasonable amount of data into the
+			 *       existing audit buffer, flush it and start with
+			 *       a new buffer */
+			if ((sizeof(abuf) + 8) > len_rem) {
+				len_rem = len_max;
+				audit_log_end(*ab);
+				*ab = audit_log_start(context,
+						      GFP_KERNEL, AUDIT_EXECVE);
+				if (!*ab)
+					goto out;
+			}
+
+			/* create the non-arg portion of the arg record */
+			len_tmp = 0;
+			if (require_data || (iter > 0) ||
+			    ((len_abuf + sizeof(abuf)) > len_rem)) {
+				if (iter == 0) {
+					len_tmp += snprintf(&abuf[len_tmp],
+							sizeof(abuf) - len_tmp,
+							" a%d_len=%lu",
+							arg, len_full);
+				}
+				len_tmp += snprintf(&abuf[len_tmp],
+						    sizeof(abuf) - len_tmp,
+						    " a%d[%d]=", arg, iter++);
+			} else
+				len_tmp += snprintf(&abuf[len_tmp],
+						    sizeof(abuf) - len_tmp,
+						    " a%d=", arg);
+			WARN_ON(len_tmp >= sizeof(abuf));
+			abuf[sizeof(abuf) - 1] = '\0';
+
+			/* log the arg in the audit record */
+			audit_log_format(*ab, "%s", abuf);
+			len_rem -= len_tmp;
+			len_tmp = len_buf;
+			if (encode) {
+				if (len_abuf > len_rem)
+					len_tmp = len_rem / 2; /* encoding */
+				audit_log_n_hex(*ab, buf, len_tmp);
+				len_rem -= len_tmp * 2;
+				len_abuf -= len_tmp * 2;
+			} else {
+				if (len_abuf > len_rem)
+					len_tmp = len_rem - 2; /* quotes */
+				audit_log_n_string(*ab, buf, len_tmp);
+				len_rem -= len_tmp + 2;
+				/* don't subtract the "2" because we still need
+				 * to add quotes to the remaining string */
+				len_abuf -= len_tmp;
+			}
+			len_buf -= len_tmp;
+			buf += len_tmp;
+		}
+
+		/* ready to move to the next argument? */
+		if ((len_buf == 0) && !require_data) {
+			arg++;
+			iter = 0;
+			len_full = 0;
+			require_data = true;
+			encode = false;
+		}
+	} while (arg < context->execve.argc);
+
+	/* NOTE: the caller handles the final audit_log_end() call */
+
+out:
+	kfree(buf_head);
+}
+
+static void audit_log_cap(struct audit_buffer *ab, char *prefix,
+			  kernel_cap_t *cap)
+{
+	int i;
+
+	if (cap_isclear(*cap)) {
+		audit_log_format(ab, " %s=0", prefix);
+		return;
+	}
+	audit_log_format(ab, " %s=", prefix);
+	CAP_FOR_EACH_U32(i)
+		audit_log_format(ab, "%08x", cap->cap[CAP_LAST_U32 - i]);
+}
+
+static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
+{
+	if (name->fcap_ver == -1) {
+		audit_log_format(ab, " cap_fe=? cap_fver=? cap_fp=? cap_fi=?");
+		return;
+	}
+	audit_log_cap(ab, "cap_fp", &name->fcap.permitted);
+	audit_log_cap(ab, "cap_fi", &name->fcap.inheritable);
+	audit_log_format(ab, " cap_fe=%d cap_fver=%x cap_frootid=%d",
+			 name->fcap.fE, name->fcap_ver,
+			 from_kuid(&init_user_ns, name->fcap.rootid));
+}
+
+static void audit_log_time(struct audit_context *context, struct audit_buffer **ab)
+{
+	const struct audit_ntp_data *ntp = &context->time.ntp_data;
+	const struct timespec64 *tk = &context->time.tk_injoffset;
+	static const char * const ntp_name[] = {
+		"offset",
+		"freq",
+		"status",
+		"tai",
+		"tick",
+		"adjust",
+	};
+	int type;
+
+	if (context->type == AUDIT_TIME_ADJNTPVAL) {
+		for (type = 0; type < AUDIT_NTP_NVALS; type++) {
+			if (ntp->vals[type].newval != ntp->vals[type].oldval) {
+				if (!*ab) {
+					*ab = audit_log_start(context,
+							GFP_KERNEL,
+							AUDIT_TIME_ADJNTPVAL);
+					if (!*ab)
+						return;
+				}
+				audit_log_format(*ab, "op=%s old=%lli new=%lli",
+						 ntp_name[type],
+						 ntp->vals[type].oldval,
+						 ntp->vals[type].newval);
+				audit_log_end(*ab);
+				*ab = NULL;
+			}
+		}
+	}
+	if (tk->tv_sec != 0 || tk->tv_nsec != 0) {
+		if (!*ab) {
+			*ab = audit_log_start(context, GFP_KERNEL,
+					      AUDIT_TIME_INJOFFSET);
+			if (!*ab)
+				return;
+		}
+		audit_log_format(*ab, "sec=%lli nsec=%li",
+				 (long long)tk->tv_sec, tk->tv_nsec);
+		audit_log_end(*ab);
+		*ab = NULL;
+	}
+}
+
+static void show_special(struct audit_context *context, int *call_panic)
+{
+	struct audit_buffer *ab;
+	int i;
+
+	ab = audit_log_start(context, GFP_KERNEL, context->type);
+	if (!ab)
+		return;
+
+	switch (context->type) {
+	case AUDIT_SOCKETCALL: {
+		int nargs = context->socketcall.nargs;
+
+		audit_log_format(ab, "nargs=%d", nargs);
+		for (i = 0; i < nargs; i++)
+			audit_log_format(ab, " a%d=%lx", i,
+				context->socketcall.args[i]);
+		break; }
+	case AUDIT_IPC: {
+		u32 osid = context->ipc.osid;
+
+		audit_log_format(ab, "ouid=%u ogid=%u mode=%#ho",
+				 from_kuid(&init_user_ns, context->ipc.uid),
+				 from_kgid(&init_user_ns, context->ipc.gid),
+				 context->ipc.mode);
+		if (osid) {
+			char *ctx = NULL;
+			u32 len;
+
+			if (security_secid_to_secctx(osid, &ctx, &len)) {
+				audit_log_format(ab, " osid=%u", osid);
+				*call_panic = 1;
+			} else {
+				audit_log_format(ab, " obj=%s", ctx);
+				security_release_secctx(ctx, len);
+			}
+		}
+		if (context->ipc.has_perm) {
+			audit_log_end(ab);
+			ab = audit_log_start(context, GFP_KERNEL,
+					     AUDIT_IPC_SET_PERM);
+			if (unlikely(!ab))
+				return;
+			audit_log_format(ab,
+				"qbytes=%lx ouid=%u ogid=%u mode=%#ho",
+				context->ipc.qbytes,
+				context->ipc.perm_uid,
+				context->ipc.perm_gid,
+				context->ipc.perm_mode);
+		}
+		break; }
+	case AUDIT_MQ_OPEN:
+		audit_log_format(ab,
+			"oflag=0x%x mode=%#ho mq_flags=0x%lx mq_maxmsg=%ld "
+			"mq_msgsize=%ld mq_curmsgs=%ld",
+			context->mq_open.oflag, context->mq_open.mode,
+			context->mq_open.attr.mq_flags,
+			context->mq_open.attr.mq_maxmsg,
+			context->mq_open.attr.mq_msgsize,
+			context->mq_open.attr.mq_curmsgs);
+		break;
+	case AUDIT_MQ_SENDRECV:
+		audit_log_format(ab,
+			"mqdes=%d msg_len=%zd msg_prio=%u "
+			"abs_timeout_sec=%lld abs_timeout_nsec=%ld",
+			context->mq_sendrecv.mqdes,
+			context->mq_sendrecv.msg_len,
+			context->mq_sendrecv.msg_prio,
+			(long long) context->mq_sendrecv.abs_timeout.tv_sec,
+			context->mq_sendrecv.abs_timeout.tv_nsec);
+		break;
+	case AUDIT_MQ_NOTIFY:
+		audit_log_format(ab, "mqdes=%d sigev_signo=%d",
+				context->mq_notify.mqdes,
+				context->mq_notify.sigev_signo);
+		break;
+	case AUDIT_MQ_GETSETATTR: {
+		struct mq_attr *attr = &context->mq_getsetattr.mqstat;
+
+		audit_log_format(ab,
+			"mqdes=%d mq_flags=0x%lx mq_maxmsg=%ld mq_msgsize=%ld "
+			"mq_curmsgs=%ld ",
+			context->mq_getsetattr.mqdes,
+			attr->mq_flags, attr->mq_maxmsg,
+			attr->mq_msgsize, attr->mq_curmsgs);
+		break; }
+	case AUDIT_CAPSET:
+		audit_log_format(ab, "pid=%d", context->capset.pid);
+		audit_log_cap(ab, "cap_pi", &context->capset.cap.inheritable);
+		audit_log_cap(ab, "cap_pp", &context->capset.cap.permitted);
+		audit_log_cap(ab, "cap_pe", &context->capset.cap.effective);
+		audit_log_cap(ab, "cap_pa", &context->capset.cap.ambient);
+		break;
+	case AUDIT_MMAP:
+		audit_log_format(ab, "fd=%d flags=0x%x", context->mmap.fd,
+				 context->mmap.flags);
+		break;
+	case AUDIT_OPENAT2:
+		audit_log_format(ab, "oflag=0%llo mode=0%llo resolve=0x%llx",
+				 context->openat2.flags,
+				 context->openat2.mode,
+				 context->openat2.resolve);
+		break;
+	case AUDIT_EXECVE:
+		audit_log_execve_info(context, &ab);
+		break;
+	case AUDIT_KERN_MODULE:
+		audit_log_format(ab, "name=");
+		if (context->module.name) {
+			audit_log_untrustedstring(ab, context->module.name);
+		} else
+			audit_log_format(ab, "(null)");
+
+		break;
+	case AUDIT_TIME_ADJNTPVAL:
+	case AUDIT_TIME_INJOFFSET:
+		/* this call deviates from the rest, eating the buffer */
+		audit_log_time(context, &ab);
+		break;
+	}
+	audit_log_end(ab);
+}
+
+static inline int audit_proctitle_rtrim(char *proctitle, int len)
+{
+	char *end = proctitle + len - 1;
+
+	while (end > proctitle && !isprint(*end))
+		end--;
+
+	/* catch the case where proctitle is only 1 non-print character */
+	len = end - proctitle + 1;
+	len -= isprint(proctitle[len-1]) == 0;
+	return len;
+}
+
+/*
+ * audit_log_name - produce AUDIT_PATH record from struct audit_names
+ * @context: audit_context for the task
+ * @n: audit_names structure with reportable details
+ * @path: optional path to report instead of audit_names->name
+ * @record_num: record number to report when handling a list of names
+ * @call_panic: optional pointer to int that will be updated if secid fails
+ */
+static void audit_log_name(struct audit_context *context, struct audit_names *n,
+		    const struct path *path, int record_num, int *call_panic)
+{
+	struct audit_buffer *ab;
+
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
+	if (!ab)
+		return;
+
+	audit_log_format(ab, "item=%d", record_num);
+
+	if (path)
+		audit_log_d_path(ab, " name=", path);
+	else if (n->name) {
+		switch (n->name_len) {
+		case AUDIT_NAME_FULL:
+			/* log the full path */
+			audit_log_format(ab, " name=");
+			audit_log_untrustedstring(ab, n->name->name);
+			break;
+		case 0:
+			/* name was specified as a relative path and the
+			 * directory component is the cwd
+			 */
+			if (context->pwd.dentry && context->pwd.mnt)
+				audit_log_d_path(ab, " name=", &context->pwd);
+			else
+				audit_log_format(ab, " name=(null)");
+			break;
+		default:
+			/* log the name's directory component */
+			audit_log_format(ab, " name=");
+			audit_log_n_untrustedstring(ab, n->name->name,
+						    n->name_len);
+		}
+	} else
+		audit_log_format(ab, " name=(null)");
+
+	if (n->ino != AUDIT_INO_UNSET)
+		audit_log_format(ab, " inode=%lu dev=%02x:%02x mode=%#ho ouid=%u ogid=%u rdev=%02x:%02x",
+				 n->ino,
+				 MAJOR(n->dev),
+				 MINOR(n->dev),
+				 n->mode,
+				 from_kuid(&init_user_ns, n->uid),
+				 from_kgid(&init_user_ns, n->gid),
+				 MAJOR(n->rdev),
+				 MINOR(n->rdev));
+	if (n->osid != 0) {
+		char *ctx = NULL;
+		u32 len;
+
+		if (security_secid_to_secctx(
+			n->osid, &ctx, &len)) {
+			audit_log_format(ab, " osid=%u", n->osid);
+			if (call_panic)
+				*call_panic = 2;
+		} else {
+			audit_log_format(ab, " obj=%s", ctx);
+			security_release_secctx(ctx, len);
+		}
+	}
+
+	/* log the audit_names record type */
+	switch (n->type) {
+	case AUDIT_TYPE_NORMAL:
+		audit_log_format(ab, " nametype=NORMAL");
+		break;
+	case AUDIT_TYPE_PARENT:
+		audit_log_format(ab, " nametype=PARENT");
+		break;
+	case AUDIT_TYPE_CHILD_DELETE:
+		audit_log_format(ab, " nametype=DELETE");
+		break;
+	case AUDIT_TYPE_CHILD_CREATE:
+		audit_log_format(ab, " nametype=CREATE");
+		break;
+	default:
+		audit_log_format(ab, " nametype=UNKNOWN");
+		break;
+	}
+
+	audit_log_fcaps(ab, n);
+	audit_log_end(ab);
+}
+
+static void audit_log_proctitle(void)
+{
+	int res;
+	char *buf;
+	char *msg = "(null)";
+	int len = strlen(msg);
+	struct audit_context *context = audit_context();
+	struct audit_buffer *ab;
+
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_PROCTITLE);
+	if (!ab)
+		return;	/* audit_panic or being filtered */
+
+	audit_log_format(ab, "proctitle=");
+
+	/* Not  cached */
+	if (!context->proctitle.value) {
+		buf = kmalloc(MAX_PROCTITLE_AUDIT_LEN, GFP_KERNEL);
+		if (!buf)
+			goto out;
+		/* Historically called this from procfs naming */
+		res = get_cmdline(current, buf, MAX_PROCTITLE_AUDIT_LEN);
+		if (res == 0) {
+			kfree(buf);
+			goto out;
+		}
+		res = audit_proctitle_rtrim(buf, res);
+		if (res == 0) {
+			kfree(buf);
+			goto out;
+		}
+		context->proctitle.value = buf;
+		context->proctitle.len = res;
+	}
+	msg = context->proctitle.value;
+	len = context->proctitle.len;
+out:
+	audit_log_n_untrustedstring(ab, msg, len);
+	audit_log_end(ab);
+}
+
+/**
+ * audit_log_uring - generate a AUDIT_URINGOP record
+ * @ctx: the audit context
+ */
+static void audit_log_uring(struct audit_context *ctx)
+{
+	struct audit_buffer *ab;
+	const struct cred *cred;
+
+	ab = audit_log_start(ctx, GFP_ATOMIC, AUDIT_URINGOP);
+	if (!ab)
+		return;
+	cred = current_cred();
+	audit_log_format(ab, "uring_op=%d", ctx->uring_op);
+	if (ctx->return_valid != AUDITSC_INVALID)
+		audit_log_format(ab, " success=%s exit=%ld",
+				 (ctx->return_valid == AUDITSC_SUCCESS ?
+				  "yes" : "no"),
+				 ctx->return_code);
+	audit_log_format(ab,
+			 " items=%d"
+			 " ppid=%d pid=%d uid=%u gid=%u euid=%u suid=%u"
+			 " fsuid=%u egid=%u sgid=%u fsgid=%u",
+			 ctx->name_count,
+			 task_ppid_nr(current), task_tgid_nr(current),
+			 from_kuid(&init_user_ns, cred->uid),
+			 from_kgid(&init_user_ns, cred->gid),
+			 from_kuid(&init_user_ns, cred->euid),
+			 from_kuid(&init_user_ns, cred->suid),
+			 from_kuid(&init_user_ns, cred->fsuid),
+			 from_kgid(&init_user_ns, cred->egid),
+			 from_kgid(&init_user_ns, cred->sgid),
+			 from_kgid(&init_user_ns, cred->fsgid));
+	audit_log_task_context(ab);
+	audit_log_key(ab, ctx->filterkey);
+	audit_log_end(ab);
+}
+
+static void audit_log_exit(void)
+{
+	int i, call_panic = 0;
+	struct audit_context *context = audit_context();
+	struct audit_buffer *ab;
+	struct audit_aux_data *aux;
+	struct audit_names *n;
+
+	context->personality = current->personality;
+
+	switch (context->context) {
+	case AUDIT_CTX_SYSCALL:
+		ab = audit_log_start(context, GFP_KERNEL, AUDIT_SYSCALL);
+		if (!ab)
+			return;
+		audit_log_format(ab, "arch=%x syscall=%d",
+				 context->arch, context->major);
+		if (context->personality != PER_LINUX)
+			audit_log_format(ab, " per=%lx", context->personality);
+		if (context->return_valid != AUDITSC_INVALID)
+			audit_log_format(ab, " success=%s exit=%ld",
+					 (context->return_valid == AUDITSC_SUCCESS ?
+					  "yes" : "no"),
+					 context->return_code);
+		audit_log_format(ab,
+				 " a0=%lx a1=%lx a2=%lx a3=%lx items=%d",
+				 context->argv[0],
+				 context->argv[1],
+				 context->argv[2],
+				 context->argv[3],
+				 context->name_count);
+		audit_log_task_info(ab);
+		audit_log_key(ab, context->filterkey);
+		audit_log_end(ab);
+		break;
+	case AUDIT_CTX_URING:
+		audit_log_uring(context);
+		break;
+	default:
+		BUG();
+		break;
+	}
+
+	for (aux = context->aux; aux; aux = aux->next) {
+
+		ab = audit_log_start(context, GFP_KERNEL, aux->type);
+		if (!ab)
+			continue; /* audit_panic has been called */
+
+		switch (aux->type) {
+
+		case AUDIT_BPRM_FCAPS: {
+			struct audit_aux_data_bprm_fcaps *axs = (void *)aux;
+
+			audit_log_format(ab, "fver=%x", axs->fcap_ver);
+			audit_log_cap(ab, "fp", &axs->fcap.permitted);
+			audit_log_cap(ab, "fi", &axs->fcap.inheritable);
+			audit_log_format(ab, " fe=%d", axs->fcap.fE);
+			audit_log_cap(ab, "old_pp", &axs->old_pcap.permitted);
+			audit_log_cap(ab, "old_pi", &axs->old_pcap.inheritable);
+			audit_log_cap(ab, "old_pe", &axs->old_pcap.effective);
+			audit_log_cap(ab, "old_pa", &axs->old_pcap.ambient);
+			audit_log_cap(ab, "pp", &axs->new_pcap.permitted);
+			audit_log_cap(ab, "pi", &axs->new_pcap.inheritable);
+			audit_log_cap(ab, "pe", &axs->new_pcap.effective);
+			audit_log_cap(ab, "pa", &axs->new_pcap.ambient);
+			audit_log_format(ab, " frootid=%d",
+					 from_kuid(&init_user_ns,
+						   axs->fcap.rootid));
+			break; }
+
+		}
+		audit_log_end(ab);
+	}
+
+	if (context->type)
+		show_special(context, &call_panic);
+
+	if (context->fds[0] >= 0) {
+		ab = audit_log_start(context, GFP_KERNEL, AUDIT_FD_PAIR);
+		if (ab) {
+			audit_log_format(ab, "fd0=%d fd1=%d",
+					context->fds[0], context->fds[1]);
+			audit_log_end(ab);
+		}
+	}
+
+	if (context->sockaddr_len) {
+		ab = audit_log_start(context, GFP_KERNEL, AUDIT_SOCKADDR);
+		if (ab) {
+			audit_log_format(ab, "saddr=");
+			audit_log_n_hex(ab, (void *)context->sockaddr,
+					context->sockaddr_len);
+			audit_log_end(ab);
+		}
+	}
+
+	for (aux = context->aux_pids; aux; aux = aux->next) {
+		struct audit_aux_data_pids *axs = (void *)aux;
+
+		for (i = 0; i < axs->pid_count; i++)
+			if (audit_log_pid_context(context, axs->target_pid[i],
+						  axs->target_auid[i],
+						  axs->target_uid[i],
+						  axs->target_sessionid[i],
+						  axs->target_sid[i],
+						  axs->target_comm[i]))
+				call_panic = 1;
+	}
+
+	if (context->target_pid &&
+	    audit_log_pid_context(context, context->target_pid,
+				  context->target_auid, context->target_uid,
+				  context->target_sessionid,
+				  context->target_sid, context->target_comm))
+			call_panic = 1;
+
+	if (context->pwd.dentry && context->pwd.mnt) {
+		ab = audit_log_start(context, GFP_KERNEL, AUDIT_CWD);
+		if (ab) {
+			audit_log_d_path(ab, "cwd=", &context->pwd);
+			audit_log_end(ab);
+		}
+	}
+
+	i = 0;
+	list_for_each_entry(n, &context->names_list, list) {
+		if (n->hidden)
+			continue;
+		audit_log_name(context, n, NULL, i++, &call_panic);
+	}
+
+	if (context->context == AUDIT_CTX_SYSCALL)
+		audit_log_proctitle();
+
+	/* Send end of event record to help user space know we are finished */
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_EOE);
+	if (ab)
+		audit_log_end(ab);
+	if (call_panic)
+		audit_panic("error in audit_log_exit()");
+}
+
+/**
+ * __audit_free - free a per-task audit context
+ * @tsk: task whose audit context block to free
+ *
+ * Called from copy_process, do_exit, and the io_uring code
+ */
+void __audit_free(struct task_struct *tsk)
+{
+	struct audit_context *context = tsk->audit_context;
+
+	if (!context)
+		return;
+
+	/* this may generate CONFIG_CHANGE records */
+	if (!list_empty(&context->killed_trees))
+		audit_kill_trees(context);
+
+	/* We are called either by do_exit() or the fork() error handling code;
+	 * in the former case tsk == current and in the latter tsk is a
+	 * random task_struct that doesn't have any meaningful data we
+	 * need to log via audit_log_exit().
+	 */
+	if (tsk == current && !context->dummy) {
+		context->return_valid = AUDITSC_INVALID;
+		context->return_code = 0;
+		if (context->context == AUDIT_CTX_SYSCALL) {
+			audit_filter_syscall(tsk, context);
+			audit_filter_inodes(tsk, context);
+			if (context->current_state == AUDIT_STATE_RECORD)
+				audit_log_exit();
+		} else if (context->context == AUDIT_CTX_URING) {
+			/* TODO: verify this case is real and valid */
+			audit_filter_uring(tsk, context);
+			audit_filter_inodes(tsk, context);
+			if (context->current_state == AUDIT_STATE_RECORD)
+				audit_log_uring(context);
+		}
+	}
+
+	audit_set_context(tsk, NULL);
+	audit_free_context(context);
+}
+
+/**
+ * audit_return_fixup - fixup the return codes in the audit_context
+ * @ctx: the audit_context
+ * @success: true/false value to indicate if the operation succeeded or not
+ * @code: operation return code
+ *
+ * We need to fixup the return code in the audit logs if the actual return
+ * codes are later going to be fixed by the arch specific signal handlers.
+ */
+static void audit_return_fixup(struct audit_context *ctx,
+			       int success, long code)
+{
+	/*
+	 * This is actually a test for:
+	 * (rc == ERESTARTSYS ) || (rc == ERESTARTNOINTR) ||
+	 * (rc == ERESTARTNOHAND) || (rc == ERESTART_RESTARTBLOCK)
+	 *
+	 * but is faster than a bunch of ||
+	 */
+	if (unlikely(code <= -ERESTARTSYS) &&
+	    (code >= -ERESTART_RESTARTBLOCK) &&
+	    (code != -ENOIOCTLCMD))
+		ctx->return_code = -EINTR;
+	else
+		ctx->return_code  = code;
+	ctx->return_valid = (success ? AUDITSC_SUCCESS : AUDITSC_FAILURE);
+}
+
+/**
+ * __audit_uring_entry - prepare the kernel task's audit context for io_uring
+ * @op: the io_uring opcode
+ *
+ * This is similar to audit_syscall_entry() but is intended for use by io_uring
+ * operations.  This function should only ever be called from
+ * audit_uring_entry() as we rely on the audit context checking present in that
+ * function.
+ */
+void __audit_uring_entry(u8 op)
+{
+	struct audit_context *ctx = audit_context();
+
+	if (ctx->state == AUDIT_STATE_DISABLED)
+		return;
+
+	/*
+	 * NOTE: It's possible that we can be called from the process' context
+	 *       before it returns to userspace, and before audit_syscall_exit()
+	 *       is called.  In this case there is not much to do, just record
+	 *       the io_uring details and return.
+	 */
+	ctx->uring_op = op;
+	if (ctx->context == AUDIT_CTX_SYSCALL)
+		return;
+
+	ctx->dummy = !audit_n_rules;
+	if (!ctx->dummy && ctx->state == AUDIT_STATE_BUILD)
+		ctx->prio = 0;
+
+	ctx->context = AUDIT_CTX_URING;
+	ctx->current_state = ctx->state;
+	ktime_get_coarse_real_ts64(&ctx->ctime);
+}
+
+/**
+ * __audit_uring_exit - wrap up the kernel task's audit context after io_uring
+ * @success: true/false value to indicate if the operation succeeded or not
+ * @code: operation return code
+ *
+ * This is similar to audit_syscall_exit() but is intended for use by io_uring
+ * operations.  This function should only ever be called from
+ * audit_uring_exit() as we rely on the audit context checking present in that
+ * function.
+ */
+void __audit_uring_exit(int success, long code)
+{
+	struct audit_context *ctx = audit_context();
+
+	if (ctx->dummy) {
+		if (ctx->context != AUDIT_CTX_URING)
+			return;
+		goto out;
+	}
+
+	audit_return_fixup(ctx, success, code);
+	if (ctx->context == AUDIT_CTX_SYSCALL) {
+		/*
+		 * NOTE: See the note in __audit_uring_entry() about the case
+		 *       where we may be called from process context before we
+		 *       return to userspace via audit_syscall_exit().  In this
+		 *       case we simply emit a URINGOP record and bail, the
+		 *       normal syscall exit handling will take care of
+		 *       everything else.
+		 *       It is also worth mentioning that when we are called,
+		 *       the current process creds may differ from the creds
+		 *       used during the normal syscall processing; keep that
+		 *       in mind if/when we move the record generation code.
+		 */
+
+		/*
+		 * We need to filter on the syscall info here to decide if we
+		 * should emit a URINGOP record.  I know it seems odd but this
+		 * solves the problem where users have a filter to block *all*
+		 * syscall records in the "exit" filter; we want to preserve
+		 * the behavior here.
+		 */
+		audit_filter_syscall(current, ctx);
+		if (ctx->current_state != AUDIT_STATE_RECORD)
+			audit_filter_uring(current, ctx);
+		audit_filter_inodes(current, ctx);
+		if (ctx->current_state != AUDIT_STATE_RECORD)
+			return;
+
+		audit_log_uring(ctx);
+		return;
+	}
+
+	/* this may generate CONFIG_CHANGE records */
+	if (!list_empty(&ctx->killed_trees))
+		audit_kill_trees(ctx);
+
+	/* run through both filters to ensure we set the filterkey properly */
+	audit_filter_uring(current, ctx);
+	audit_filter_inodes(current, ctx);
+	if (ctx->current_state != AUDIT_STATE_RECORD)
+		goto out;
+	audit_log_exit();
+
+out:
+	audit_reset_context(ctx);
+}
+
+/**
+ * __audit_syscall_entry - fill in an audit record at syscall entry
+ * @major: major syscall type (function)
+ * @a1: additional syscall register 1
+ * @a2: additional syscall register 2
+ * @a3: additional syscall register 3
+ * @a4: additional syscall register 4
+ *
+ * Fill in audit context at syscall entry.  This only happens if the
+ * audit context was created when the task was created and the state or
+ * filters demand the audit context be built.  If the state from the
+ * per-task filter or from the per-syscall filter is AUDIT_STATE_RECORD,
+ * then the record will be written at syscall exit time (otherwise, it
+ * will only be written if another part of the kernel requests that it
+ * be written).
+ */
+void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2,
+			   unsigned long a3, unsigned long a4)
+{
+	struct audit_context *context = audit_context();
+	enum audit_state     state;
+
+	if (!audit_enabled || !context)
+		return;
+
+	WARN_ON(context->context != AUDIT_CTX_UNUSED);
+	WARN_ON(context->name_count);
+	if (context->context != AUDIT_CTX_UNUSED || context->name_count) {
+		audit_panic("unrecoverable error in audit_syscall_entry()");
+		return;
+	}
+
+	state = context->state;
+	if (state == AUDIT_STATE_DISABLED)
+		return;
+
+	context->dummy = !audit_n_rules;
+	if (!context->dummy && state == AUDIT_STATE_BUILD) {
+		context->prio = 0;
+		if (auditd_test_task(current))
+			return;
+	}
+
+	context->arch	    = syscall_get_arch(current);
+	context->major      = major;
+	context->argv[0]    = a1;
+	context->argv[1]    = a2;
+	context->argv[2]    = a3;
+	context->argv[3]    = a4;
+	context->context = AUDIT_CTX_SYSCALL;
+	context->current_state  = state;
+	ktime_get_coarse_real_ts64(&context->ctime);
+}
+
+/**
+ * __audit_syscall_exit - deallocate audit context after a system call
+ * @success: success value of the syscall
+ * @return_code: return value of the syscall
+ *
+ * Tear down after system call.  If the audit context has been marked as
+ * auditable (either because of the AUDIT_STATE_RECORD state from
+ * filtering, or because some other part of the kernel wrote an audit
+ * message), then write out the syscall information.  In call cases,
+ * free the names stored from getname().
+ */
+void __audit_syscall_exit(int success, long return_code)
+{
+	struct audit_context *context = audit_context();
+
+	if (!context || context->dummy ||
+	    context->context != AUDIT_CTX_SYSCALL)
+		goto out;
+
+	/* this may generate CONFIG_CHANGE records */
+	if (!list_empty(&context->killed_trees))
+		audit_kill_trees(context);
+
+	audit_return_fixup(context, success, return_code);
+	/* run through both filters to ensure we set the filterkey properly */
+	audit_filter_syscall(current, context);
+	audit_filter_inodes(current, context);
+	if (context->current_state != AUDIT_STATE_RECORD)
+		goto out;
+
+	audit_log_exit();
+
+out:
+	audit_reset_context(context);
+}
+
+static inline void handle_one(const struct inode *inode)
+{
+	struct audit_context *context;
+	struct audit_tree_refs *p;
+	struct audit_chunk *chunk;
+	int count;
+
+	if (likely(!inode->i_fsnotify_marks))
+		return;
+	context = audit_context();
+	p = context->trees;
+	count = context->tree_count;
+	rcu_read_lock();
+	chunk = audit_tree_lookup(inode);
+	rcu_read_unlock();
+	if (!chunk)
+		return;
+	if (likely(put_tree_ref(context, chunk)))
+		return;
+	if (unlikely(!grow_tree_refs(context))) {
+		pr_warn("out of memory, audit has lost a tree reference\n");
+		audit_set_auditable(context);
+		audit_put_chunk(chunk);
+		unroll_tree_refs(context, p, count);
+		return;
+	}
+	put_tree_ref(context, chunk);
+}
+
+static void handle_path(const struct dentry *dentry)
+{
+	struct audit_context *context;
+	struct audit_tree_refs *p;
+	const struct dentry *d, *parent;
+	struct audit_chunk *drop;
+	unsigned long seq;
+	int count;
+
+	context = audit_context();
+	p = context->trees;
+	count = context->tree_count;
+retry:
+	drop = NULL;
+	d = dentry;
+	rcu_read_lock();
+	seq = read_seqbegin(&rename_lock);
+	for(;;) {
+		struct inode *inode = d_backing_inode(d);
+
+		if (inode && unlikely(inode->i_fsnotify_marks)) {
+			struct audit_chunk *chunk;
+
+			chunk = audit_tree_lookup(inode);
+			if (chunk) {
+				if (unlikely(!put_tree_ref(context, chunk))) {
+					drop = chunk;
+					break;
+				}
+			}
+		}
+		parent = d->d_parent;
+		if (parent == d)
+			break;
+		d = parent;
+	}
+	if (unlikely(read_seqretry(&rename_lock, seq) || drop)) {  /* in this order */
+		rcu_read_unlock();
+		if (!drop) {
+			/* just a race with rename */
+			unroll_tree_refs(context, p, count);
+			goto retry;
+		}
+		audit_put_chunk(drop);
+		if (grow_tree_refs(context)) {
+			/* OK, got more space */
+			unroll_tree_refs(context, p, count);
+			goto retry;
+		}
+		/* too bad */
+		pr_warn("out of memory, audit has lost a tree reference\n");
+		unroll_tree_refs(context, p, count);
+		audit_set_auditable(context);
+		return;
+	}
+	rcu_read_unlock();
+}
+
+static struct audit_names *audit_alloc_name(struct audit_context *context,
+						unsigned char type)
+{
+	struct audit_names *aname;
+
+	if (context->name_count < AUDIT_NAMES) {
+		aname = &context->preallocated_names[context->name_count];
+		memset(aname, 0, sizeof(*aname));
+	} else {
+		aname = kzalloc(sizeof(*aname), GFP_NOFS);
+		if (!aname)
+			return NULL;
+		aname->should_free = true;
+	}
+
+	aname->ino = AUDIT_INO_UNSET;
+	aname->type = type;
+	list_add_tail(&aname->list, &context->names_list);
+
+	context->name_count++;
+	if (!context->pwd.dentry)
+		get_fs_pwd(current->fs, &context->pwd);
+	return aname;
+}
+
+/**
+ * __audit_reusename - fill out filename with info from existing entry
+ * @uptr: userland ptr to pathname
+ *
+ * Search the audit_names list for the current audit context. If there is an
+ * existing entry with a matching "uptr" then return the filename
+ * associated with that audit_name. If not, return NULL.
+ */
+struct filename *
+__audit_reusename(const __user char *uptr)
+{
+	struct audit_context *context = audit_context();
+	struct audit_names *n;
+
+	list_for_each_entry(n, &context->names_list, list) {
+		if (!n->name)
+			continue;
+		if (n->name->uptr == uptr) {
+			atomic_inc(&n->name->refcnt);
+			return n->name;
+		}
+	}
+	return NULL;
+}
+
+/**
+ * __audit_getname - add a name to the list
+ * @name: name to add
+ *
+ * Add a name to the list of audit names for this context.
+ * Called from fs/namei.c:getname().
+ */
+void __audit_getname(struct filename *name)
+{
+	struct audit_context *context = audit_context();
+	struct audit_names *n;
+
+	if (context->context == AUDIT_CTX_UNUSED)
+		return;
+
+	n = audit_alloc_name(context, AUDIT_TYPE_UNKNOWN);
+	if (!n)
+		return;
+
+	n->name = name;
+	n->name_len = AUDIT_NAME_FULL;
+	name->aname = n;
+	atomic_inc(&name->refcnt);
+}
+
+static inline int audit_copy_fcaps(struct audit_names *name,
+				   const struct dentry *dentry)
+{
+	struct cpu_vfs_cap_data caps;
+	int rc;
+
+	if (!dentry)
+		return 0;
+
+	rc = get_vfs_caps_from_disk(&init_user_ns, dentry, &caps);
+	if (rc)
+		return rc;
+
+	name->fcap.permitted = caps.permitted;
+	name->fcap.inheritable = caps.inheritable;
+	name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
+	name->fcap.rootid = caps.rootid;
+	name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
+				VFS_CAP_REVISION_SHIFT;
+
+	return 0;
+}
+
+/* Copy inode data into an audit_names. */
+static void audit_copy_inode(struct audit_names *name,
+			     const struct dentry *dentry,
+			     struct inode *inode, unsigned int flags)
+{
+	name->ino   = inode->i_ino;
+	name->dev   = inode->i_sb->s_dev;
+	name->mode  = inode->i_mode;
+	name->uid   = inode->i_uid;
+	name->gid   = inode->i_gid;
+	name->rdev  = inode->i_rdev;
+	security_inode_getsecid(inode, &name->osid);
+	if (flags & AUDIT_INODE_NOEVAL) {
+		name->fcap_ver = -1;
+		return;
+	}
+	audit_copy_fcaps(name, dentry);
+}
+
+/**
+ * __audit_inode - store the inode and device from a lookup
+ * @name: name being audited
+ * @dentry: dentry being audited
+ * @flags: attributes for this particular entry
+ */
+void __audit_inode(struct filename *name, const struct dentry *dentry,
+		   unsigned int flags)
+{
+	struct audit_context *context = audit_context();
+	struct inode *inode = d_backing_inode(dentry);
+	struct audit_names *n;
+	bool parent = flags & AUDIT_INODE_PARENT;
+	struct audit_entry *e;
+	struct list_head *list = &audit_filter_list[AUDIT_FILTER_FS];
+	int i;
+
+	if (context->context == AUDIT_CTX_UNUSED)
+		return;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(e, list, list) {
+		for (i = 0; i < e->rule.field_count; i++) {
+			struct audit_field *f = &e->rule.fields[i];
+
+			if (f->type == AUDIT_FSTYPE
+			    && audit_comparator(inode->i_sb->s_magic,
+						f->op, f->val)
+			    && e->rule.action == AUDIT_NEVER) {
+				rcu_read_unlock();
+				return;
+			}
+		}
+	}
+	rcu_read_unlock();
+
+	if (!name)
+		goto out_alloc;
+
+	/*
+	 * If we have a pointer to an audit_names entry already, then we can
+	 * just use it directly if the type is correct.
+	 */
+	n = name->aname;
+	if (n) {
+		if (parent) {
+			if (n->type == AUDIT_TYPE_PARENT ||
+			    n->type == AUDIT_TYPE_UNKNOWN)
+				goto out;
+		} else {
+			if (n->type != AUDIT_TYPE_PARENT)
+				goto out;
+		}
+	}
+
+	list_for_each_entry_reverse(n, &context->names_list, list) {
+		if (n->ino) {
+			/* valid inode number, use that for the comparison */
+			if (n->ino != inode->i_ino ||
+			    n->dev != inode->i_sb->s_dev)
+				continue;
+		} else if (n->name) {
+			/* inode number has not been set, check the name */
+			if (strcmp(n->name->name, name->name))
+				continue;
+		} else
+			/* no inode and no name (?!) ... this is odd ... */
+			continue;
+
+		/* match the correct record type */
+		if (parent) {
+			if (n->type == AUDIT_TYPE_PARENT ||
+			    n->type == AUDIT_TYPE_UNKNOWN)
+				goto out;
+		} else {
+			if (n->type != AUDIT_TYPE_PARENT)
+				goto out;
+		}
+	}
+
+out_alloc:
+	/* unable to find an entry with both a matching name and type */
+	n = audit_alloc_name(context, AUDIT_TYPE_UNKNOWN);
+	if (!n)
+		return;
+	if (name) {
+		n->name = name;
+		atomic_inc(&name->refcnt);
+	}
+
+out:
+	if (parent) {
+		n->name_len = n->name ? parent_len(n->name->name) : AUDIT_NAME_FULL;
+		n->type = AUDIT_TYPE_PARENT;
+		if (flags & AUDIT_INODE_HIDDEN)
+			n->hidden = true;
+	} else {
+		n->name_len = AUDIT_NAME_FULL;
+		n->type = AUDIT_TYPE_NORMAL;
+	}
+	handle_path(dentry);
+	audit_copy_inode(n, dentry, inode, flags & AUDIT_INODE_NOEVAL);
+}
+
+void __audit_file(const struct file *file)
+{
+	__audit_inode(NULL, file->f_path.dentry, 0);
+}
+
+/**
+ * __audit_inode_child - collect inode info for created/removed objects
+ * @parent: inode of dentry parent
+ * @dentry: dentry being audited
+ * @type:   AUDIT_TYPE_* value that we're looking for
+ *
+ * For syscalls that create or remove filesystem objects, audit_inode
+ * can only collect information for the filesystem object's parent.
+ * This call updates the audit context with the child's information.
+ * Syscalls that create a new filesystem object must be hooked after
+ * the object is created.  Syscalls that remove a filesystem object
+ * must be hooked prior, in order to capture the target inode during
+ * unsuccessful attempts.
+ */
+void __audit_inode_child(struct inode *parent,
+			 const struct dentry *dentry,
+			 const unsigned char type)
+{
+	struct audit_context *context = audit_context();
+	struct inode *inode = d_backing_inode(dentry);
+	const struct qstr *dname = &dentry->d_name;
+	struct audit_names *n, *found_parent = NULL, *found_child = NULL;
+	struct audit_entry *e;
+	struct list_head *list = &audit_filter_list[AUDIT_FILTER_FS];
+	int i;
+
+	if (context->context == AUDIT_CTX_UNUSED)
+		return;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(e, list, list) {
+		for (i = 0; i < e->rule.field_count; i++) {
+			struct audit_field *f = &e->rule.fields[i];
+
+			if (f->type == AUDIT_FSTYPE
+			    && audit_comparator(parent->i_sb->s_magic,
+						f->op, f->val)
+			    && e->rule.action == AUDIT_NEVER) {
+				rcu_read_unlock();
+				return;
+			}
+		}
+	}
+	rcu_read_unlock();
+
+	if (inode)
+		handle_one(inode);
+
+	/* look for a parent entry first */
+	list_for_each_entry(n, &context->names_list, list) {
+		if (!n->name ||
+		    (n->type != AUDIT_TYPE_PARENT &&
+		     n->type != AUDIT_TYPE_UNKNOWN))
+			continue;
+
+		if (n->ino == parent->i_ino && n->dev == parent->i_sb->s_dev &&
+		    !audit_compare_dname_path(dname,
+					      n->name->name, n->name_len)) {
+			if (n->type == AUDIT_TYPE_UNKNOWN)
+				n->type = AUDIT_TYPE_PARENT;
+			found_parent = n;
+			break;
+		}
+	}
+
+	cond_resched();
+
+	/* is there a matching child entry? */
+	list_for_each_entry(n, &context->names_list, list) {
+		/* can only match entries that have a name */
+		if (!n->name ||
+		    (n->type != type && n->type != AUDIT_TYPE_UNKNOWN))
+			continue;
+
+		if (!strcmp(dname->name, n->name->name) ||
+		    !audit_compare_dname_path(dname, n->name->name,
+						found_parent ?
+						found_parent->name_len :
+						AUDIT_NAME_FULL)) {
+			if (n->type == AUDIT_TYPE_UNKNOWN)
+				n->type = type;
+			found_child = n;
+			break;
+		}
+	}
+
+	if (!found_parent) {
+		/* create a new, "anonymous" parent record */
+		n = audit_alloc_name(context, AUDIT_TYPE_PARENT);
+		if (!n)
+			return;
+		audit_copy_inode(n, NULL, parent, 0);
+	}
+
+	if (!found_child) {
+		found_child = audit_alloc_name(context, type);
+		if (!found_child)
+			return;
+
+		/* Re-use the name belonging to the slot for a matching parent
+		 * directory. All names for this context are relinquished in
+		 * audit_free_names() */
+		if (found_parent) {
+			found_child->name = found_parent->name;
+			found_child->name_len = AUDIT_NAME_FULL;
+			atomic_inc(&found_child->name->refcnt);
+		}
+	}
+
+	if (inode)
+		audit_copy_inode(found_child, dentry, inode, 0);
+	else
+		found_child->ino = AUDIT_INO_UNSET;
+}
+EXPORT_SYMBOL_GPL(__audit_inode_child);
+
+/**
+ * auditsc_get_stamp - get local copies of audit_context values
+ * @ctx: audit_context for the task
+ * @t: timespec64 to store time recorded in the audit_context
+ * @serial: serial value that is recorded in the audit_context
+ *
+ * Also sets the context as auditable.
+ */
+int auditsc_get_stamp(struct audit_context *ctx,
+		       struct timespec64 *t, unsigned int *serial)
+{
+	if (ctx->context == AUDIT_CTX_UNUSED)
+		return 0;
+	if (!ctx->serial)
+		ctx->serial = audit_serial();
+	t->tv_sec  = ctx->ctime.tv_sec;
+	t->tv_nsec = ctx->ctime.tv_nsec;
+	*serial    = ctx->serial;
+	if (!ctx->prio) {
+		ctx->prio = 1;
+		ctx->current_state = AUDIT_STATE_RECORD;
+	}
+	return 1;
+}
+
+/**
+ * __audit_mq_open - record audit data for a POSIX MQ open
+ * @oflag: open flag
+ * @mode: mode bits
+ * @attr: queue attributes
+ *
+ */
+void __audit_mq_open(int oflag, umode_t mode, struct mq_attr *attr)
+{
+	struct audit_context *context = audit_context();
+
+	if (attr)
+		memcpy(&context->mq_open.attr, attr, sizeof(struct mq_attr));
+	else
+		memset(&context->mq_open.attr, 0, sizeof(struct mq_attr));
+
+	context->mq_open.oflag = oflag;
+	context->mq_open.mode = mode;
+
+	context->type = AUDIT_MQ_OPEN;
+}
+
+/**
+ * __audit_mq_sendrecv - record audit data for a POSIX MQ timed send/receive
+ * @mqdes: MQ descriptor
+ * @msg_len: Message length
+ * @msg_prio: Message priority
+ * @abs_timeout: Message timeout in absolute time
+ *
+ */
+void __audit_mq_sendrecv(mqd_t mqdes, size_t msg_len, unsigned int msg_prio,
+			const struct timespec64 *abs_timeout)
+{
+	struct audit_context *context = audit_context();
+	struct timespec64 *p = &context->mq_sendrecv.abs_timeout;
+
+	if (abs_timeout)
+		memcpy(p, abs_timeout, sizeof(*p));
+	else
+		memset(p, 0, sizeof(*p));
+
+	context->mq_sendrecv.mqdes = mqdes;
+	context->mq_sendrecv.msg_len = msg_len;
+	context->mq_sendrecv.msg_prio = msg_prio;
+
+	context->type = AUDIT_MQ_SENDRECV;
+}
+
+/**
+ * __audit_mq_notify - record audit data for a POSIX MQ notify
+ * @mqdes: MQ descriptor
+ * @notification: Notification event
+ *
+ */
+
+void __audit_mq_notify(mqd_t mqdes, const struct sigevent *notification)
+{
+	struct audit_context *context = audit_context();
+
+	if (notification)
+		context->mq_notify.sigev_signo = notification->sigev_signo;
+	else
+		context->mq_notify.sigev_signo = 0;
+
+	context->mq_notify.mqdes = mqdes;
+	context->type = AUDIT_MQ_NOTIFY;
+}
+
+/**
+ * __audit_mq_getsetattr - record audit data for a POSIX MQ get/set attribute
+ * @mqdes: MQ descriptor
+ * @mqstat: MQ flags
+ *
+ */
+void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
+{
+	struct audit_context *context = audit_context();
+
+	context->mq_getsetattr.mqdes = mqdes;
+	context->mq_getsetattr.mqstat = *mqstat;
+	context->type = AUDIT_MQ_GETSETATTR;
+}
+
+/**
+ * __audit_ipc_obj - record audit data for ipc object
+ * @ipcp: ipc permissions
+ *
+ */
+void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
+{
+	struct audit_context *context = audit_context();
+
+	context->ipc.uid = ipcp->uid;
+	context->ipc.gid = ipcp->gid;
+	context->ipc.mode = ipcp->mode;
+	context->ipc.has_perm = 0;
+	security_ipc_getsecid(ipcp, &context->ipc.osid);
+	context->type = AUDIT_IPC;
+}
+
+/**
+ * __audit_ipc_set_perm - record audit data for new ipc permissions
+ * @qbytes: msgq bytes
+ * @uid: msgq user id
+ * @gid: msgq group id
+ * @mode: msgq mode (permissions)
+ *
+ * Called only after audit_ipc_obj().
+ */
+void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode)
+{
+	struct audit_context *context = audit_context();
+
+	context->ipc.qbytes = qbytes;
+	context->ipc.perm_uid = uid;
+	context->ipc.perm_gid = gid;
+	context->ipc.perm_mode = mode;
+	context->ipc.has_perm = 1;
+}
+
+void __audit_bprm(struct linux_binprm *bprm)
+{
+	struct audit_context *context = audit_context();
+
+	context->type = AUDIT_EXECVE;
+	context->execve.argc = bprm->argc;
+}
+
+
+/**
+ * __audit_socketcall - record audit data for sys_socketcall
+ * @nargs: number of args, which should not be more than AUDITSC_ARGS.
+ * @args: args array
+ *
+ */
+int __audit_socketcall(int nargs, unsigned long *args)
+{
+	struct audit_context *context = audit_context();
+
+	if (nargs <= 0 || nargs > AUDITSC_ARGS || !args)
+		return -EINVAL;
+	context->type = AUDIT_SOCKETCALL;
+	context->socketcall.nargs = nargs;
+	memcpy(context->socketcall.args, args, nargs * sizeof(unsigned long));
+	return 0;
+}
+
+/**
+ * __audit_fd_pair - record audit data for pipe and socketpair
+ * @fd1: the first file descriptor
+ * @fd2: the second file descriptor
+ *
+ */
+void __audit_fd_pair(int fd1, int fd2)
+{
+	struct audit_context *context = audit_context();
+
+	context->fds[0] = fd1;
+	context->fds[1] = fd2;
+}
+
+/**
+ * __audit_sockaddr - record audit data for sys_bind, sys_connect, sys_sendto
+ * @len: data length in user space
+ * @a: data address in kernel space
+ *
+ * Returns 0 for success or NULL context or < 0 on error.
+ */
+int __audit_sockaddr(int len, void *a)
+{
+	struct audit_context *context = audit_context();
+
+	if (!context->sockaddr) {
+		void *p = kmalloc(sizeof(struct sockaddr_storage), GFP_KERNEL);
+
+		if (!p)
+			return -ENOMEM;
+		context->sockaddr = p;
+	}
+
+	context->sockaddr_len = len;
+	memcpy(context->sockaddr, a, len);
+	return 0;
+}
+
+void __audit_ptrace(struct task_struct *t)
+{
+	struct audit_context *context = audit_context();
+
+	context->target_pid = task_tgid_nr(t);
+	context->target_auid = audit_get_loginuid(t);
+	context->target_uid = task_uid(t);
+	context->target_sessionid = audit_get_sessionid(t);
+	security_task_getsecid_obj(t, &context->target_sid);
+	memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
+}
+
+/**
+ * audit_signal_info_syscall - record signal info for syscalls
+ * @t: task being signaled
+ *
+ * If the audit subsystem is being terminated, record the task (pid)
+ * and uid that is doing that.
+ */
+int audit_signal_info_syscall(struct task_struct *t)
+{
+	struct audit_aux_data_pids *axp;
+	struct audit_context *ctx = audit_context();
+	kuid_t t_uid = task_uid(t);
+
+	if (!audit_signals || audit_dummy_context())
+		return 0;
+
+	/* optimize the common case by putting first signal recipient directly
+	 * in audit_context */
+	if (!ctx->target_pid) {
+		ctx->target_pid = task_tgid_nr(t);
+		ctx->target_auid = audit_get_loginuid(t);
+		ctx->target_uid = t_uid;
+		ctx->target_sessionid = audit_get_sessionid(t);
+		security_task_getsecid_obj(t, &ctx->target_sid);
+		memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
+		return 0;
+	}
+
+	axp = (void *)ctx->aux_pids;
+	if (!axp || axp->pid_count == AUDIT_AUX_PIDS) {
+		axp = kzalloc(sizeof(*axp), GFP_ATOMIC);
+		if (!axp)
+			return -ENOMEM;
+
+		axp->d.type = AUDIT_OBJ_PID;
+		axp->d.next = ctx->aux_pids;
+		ctx->aux_pids = (void *)axp;
+	}
+	BUG_ON(axp->pid_count >= AUDIT_AUX_PIDS);
+
+	axp->target_pid[axp->pid_count] = task_tgid_nr(t);
+	axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
+	axp->target_uid[axp->pid_count] = t_uid;
+	axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
+	security_task_getsecid_obj(t, &axp->target_sid[axp->pid_count]);
+	memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
+	axp->pid_count++;
+
+	return 0;
+}
+
+/**
+ * __audit_log_bprm_fcaps - store information about a loading bprm and relevant fcaps
+ * @bprm: pointer to the bprm being processed
+ * @new: the proposed new credentials
+ * @old: the old credentials
+ *
+ * Simply check if the proc already has the caps given by the file and if not
+ * store the priv escalation info for later auditing at the end of the syscall
+ *
+ * -Eric
+ */
+int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
+			   const struct cred *new, const struct cred *old)
+{
+	struct audit_aux_data_bprm_fcaps *ax;
+	struct audit_context *context = audit_context();
+	struct cpu_vfs_cap_data vcaps;
+
+	ax = kmalloc(sizeof(*ax), GFP_KERNEL);
+	if (!ax)
+		return -ENOMEM;
+
+	ax->d.type = AUDIT_BPRM_FCAPS;
+	ax->d.next = context->aux;
+	context->aux = (void *)ax;
+
+	get_vfs_caps_from_disk(&init_user_ns,
+			       bprm->file->f_path.dentry, &vcaps);
+
+	ax->fcap.permitted = vcaps.permitted;
+	ax->fcap.inheritable = vcaps.inheritable;
+	ax->fcap.fE = !!(vcaps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
+	ax->fcap.rootid = vcaps.rootid;
+	ax->fcap_ver = (vcaps.magic_etc & VFS_CAP_REVISION_MASK) >> VFS_CAP_REVISION_SHIFT;
+
+	ax->old_pcap.permitted   = old->cap_permitted;
+	ax->old_pcap.inheritable = old->cap_inheritable;
+	ax->old_pcap.effective   = old->cap_effective;
+	ax->old_pcap.ambient     = old->cap_ambient;
+
+	ax->new_pcap.permitted   = new->cap_permitted;
+	ax->new_pcap.inheritable = new->cap_inheritable;
+	ax->new_pcap.effective   = new->cap_effective;
+	ax->new_pcap.ambient     = new->cap_ambient;
+	return 0;
+}
+
+/**
+ * __audit_log_capset - store information about the arguments to the capset syscall
+ * @new: the new credentials
+ * @old: the old (current) credentials
+ *
+ * Record the arguments userspace sent to sys_capset for later printing by the
+ * audit system if applicable
+ */
+void __audit_log_capset(const struct cred *new, const struct cred *old)
+{
+	struct audit_context *context = audit_context();
+
+	context->capset.pid = task_tgid_nr(current);
+	context->capset.cap.effective   = new->cap_effective;
+	context->capset.cap.inheritable = new->cap_effective;
+	context->capset.cap.permitted   = new->cap_permitted;
+	context->capset.cap.ambient     = new->cap_ambient;
+	context->type = AUDIT_CAPSET;
+}
+
+void __audit_mmap_fd(int fd, int flags)
+{
+	struct audit_context *context = audit_context();
+
+	context->mmap.fd = fd;
+	context->mmap.flags = flags;
+	context->type = AUDIT_MMAP;
+}
+
+void __audit_openat2_how(struct open_how *how)
+{
+	struct audit_context *context = audit_context();
+
+	context->openat2.flags = how->flags;
+	context->openat2.mode = how->mode;
+	context->openat2.resolve = how->resolve;
+	context->type = AUDIT_OPENAT2;
+}
+
+void __audit_log_kern_module(char *name)
+{
+	struct audit_context *context = audit_context();
+
+	context->module.name = kstrdup(name, GFP_KERNEL);
+	if (!context->module.name)
+		audit_log_lost("out of memory in __audit_log_kern_module");
+	context->type = AUDIT_KERN_MODULE;
+}
+
+void __audit_fanotify(unsigned int response)
+{
+	audit_log(audit_context(), GFP_KERNEL,
+		AUDIT_FANOTIFY,	"resp=%u", response);
+}
+
+void __audit_tk_injoffset(struct timespec64 offset)
+{
+	struct audit_context *context = audit_context();
+
+	/* only set type if not already set by NTP */
+	if (!context->type)
+		context->type = AUDIT_TIME_INJOFFSET;
+	memcpy(&context->time.tk_injoffset, &offset, sizeof(offset));
+}
+
+void __audit_ntp_log(const struct audit_ntp_data *ad)
+{
+	struct audit_context *context = audit_context();
+	int type;
+
+	for (type = 0; type < AUDIT_NTP_NVALS; type++)
+		if (ad->vals[type].newval != ad->vals[type].oldval) {
+			/* unconditionally set type, overwriting TK */
+			context->type = AUDIT_TIME_ADJNTPVAL;
+			memcpy(&context->time.ntp_data, ad, sizeof(*ad));
+			break;
+		}
+}
+
+void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
+		       enum audit_nfcfgop op, gfp_t gfp)
+{
+	struct audit_buffer *ab;
+	char comm[sizeof(current->comm)];
+
+	ab = audit_log_start(audit_context(), gfp, AUDIT_NETFILTER_CFG);
+	if (!ab)
+		return;
+	audit_log_format(ab, "table=%s family=%u entries=%u op=%s",
+			 name, af, nentries, audit_nfcfgs[op].s);
+
+	audit_log_format(ab, " pid=%u", task_pid_nr(current));
+	audit_log_task_context(ab); /* subj= */
+	audit_log_format(ab, " comm=");
+	audit_log_untrustedstring(ab, get_task_comm(comm, current));
+	audit_log_end(ab);
+}
+EXPORT_SYMBOL_GPL(__audit_log_nfcfg);
+
+static void audit_log_task(struct audit_buffer *ab)
+{
+	kuid_t auid, uid;
+	kgid_t gid;
+	unsigned int sessionid;
+	char comm[sizeof(current->comm)];
+
+	auid = audit_get_loginuid(current);
+	sessionid = audit_get_sessionid(current);
+	current_uid_gid(&uid, &gid);
+
+	audit_log_format(ab, "auid=%u uid=%u gid=%u ses=%u",
+			 from_kuid(&init_user_ns, auid),
+			 from_kuid(&init_user_ns, uid),
+			 from_kgid(&init_user_ns, gid),
+			 sessionid);
+	audit_log_task_context(ab);
+	audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current));
+	audit_log_untrustedstring(ab, get_task_comm(comm, current));
+	audit_log_d_path_exe(ab, current->mm);
+}
+
+/**
+ * audit_core_dumps - record information about processes that end abnormally
+ * @signr: signal value
+ *
+ * If a process ends with a core dump, something fishy is going on and we
+ * should record the event for investigation.
+ */
+void audit_core_dumps(long signr)
+{
+	struct audit_buffer *ab;
+
+	if (!audit_enabled)
+		return;
+
+	if (signr == SIGQUIT)	/* don't care for those */
+		return;
+
+	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_ABEND);
+	if (unlikely(!ab))
+		return;
+	audit_log_task(ab);
+	audit_log_format(ab, " sig=%ld res=1", signr);
+	audit_log_end(ab);
+}
+
+/**
+ * audit_seccomp - record information about a seccomp action
+ * @syscall: syscall number
+ * @signr: signal value
+ * @code: the seccomp action
+ *
+ * Record the information associated with a seccomp action. Event filtering for
+ * seccomp actions that are not to be logged is done in seccomp_log().
+ * Therefore, this function forces auditing independent of the audit_enabled
+ * and dummy context state because seccomp actions should be logged even when
+ * audit is not in use.
+ */
+void audit_seccomp(unsigned long syscall, long signr, int code)
+{
+	struct audit_buffer *ab;
+
+	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_SECCOMP);
+	if (unlikely(!ab))
+		return;
+	audit_log_task(ab);
+	audit_log_format(ab, " sig=%ld arch=%x syscall=%ld compat=%d ip=0x%lx code=0x%x",
+			 signr, syscall_get_arch(current), syscall,
+			 in_compat_syscall(), KSTK_EIP(current), code);
+	audit_log_end(ab);
+}
+
+void audit_seccomp_actions_logged(const char *names, const char *old_names,
+				  int res)
+{
+	struct audit_buffer *ab;
+
+	if (!audit_enabled)
+		return;
+
+	ab = audit_log_start(audit_context(), GFP_KERNEL,
+			     AUDIT_CONFIG_CHANGE);
+	if (unlikely(!ab))
+		return;
+
+	audit_log_format(ab,
+			 "op=seccomp-logging actions=%s old-actions=%s res=%d",
+			 names, old_names, res);
+	audit_log_end(ab);
+}
+
+struct list_head *audit_killed_trees(void)
+{
+	struct audit_context *ctx = audit_context();
+	if (likely(!ctx || ctx->context == AUDIT_CTX_UNUSED))
+		return NULL;
+	return &ctx->killed_trees;
+}
diff --git a/kernel/backtracetest.c b/kernel/backtracetest.c
new file mode 100644
index 000000000..370217dd7
--- /dev/null
+++ b/kernel/backtracetest.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Simple stack backtrace regression test module
+ *
+ * (C) Copyright 2008 Intel Corporation
+ * Author: Arjan van de Ven <arjan@linux.intel.com>
+ */
+
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+
+static void backtrace_test_normal(void)
+{
+	pr_info("Testing a backtrace from process context.\n");
+	pr_info("The following trace is a kernel self test and not a bug!\n");
+
+	dump_stack();
+}
+
+static DECLARE_COMPLETION(backtrace_work);
+
+static void backtrace_test_irq_callback(unsigned long data)
+{
+	dump_stack();
+	complete(&backtrace_work);
+}
+
+static DECLARE_TASKLET_OLD(backtrace_tasklet, &backtrace_test_irq_callback);
+
+static void backtrace_test_irq(void)
+{
+	pr_info("Testing a backtrace from irq context.\n");
+	pr_info("The following trace is a kernel self test and not a bug!\n");
+
+	init_completion(&backtrace_work);
+	tasklet_schedule(&backtrace_tasklet);
+	wait_for_completion(&backtrace_work);
+}
+
+#ifdef CONFIG_STACKTRACE
+static void backtrace_test_saved(void)
+{
+	unsigned long entries[8];
+	unsigned int nr_entries;
+
+	pr_info("Testing a saved backtrace.\n");
+	pr_info("The following trace is a kernel self test and not a bug!\n");
+
+	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
+	stack_trace_print(entries, nr_entries, 0);
+}
+#else
+static void backtrace_test_saved(void)
+{
+	pr_info("Saved backtrace test skipped.\n");
+}
+#endif
+
+static int backtrace_regression_test(void)
+{
+	pr_info("====[ backtrace testing ]===========\n");
+
+	backtrace_test_normal();
+	backtrace_test_irq();
+	backtrace_test_saved();
+
+	pr_info("====[ end of backtrace testing ]====\n");
+	return 0;
+}
+
+static void exitf(void)
+{
+}
+
+module_init(backtrace_regression_test);
+module_exit(exitf);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
diff --git a/kernel/bounds.c b/kernel/bounds.c
new file mode 100644
index 000000000..b529182e8
--- /dev/null
+++ b/kernel/bounds.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generate definitions needed by the preprocessor.
+ * This code generates raw asm output which is post-processed
+ * to extract and format the required data.
+ */
+
+#define __GENERATING_BOUNDS_H
+/* Include headers that define the enum constants of interest */
+#include <linux/page-flags.h>
+#include <linux/mmzone.h>
+#include <linux/kbuild.h>
+#include <linux/log2.h>
+#include <linux/spinlock_types.h>
+
+int main(void)
+{
+	/* The enum constants to put into include/generated/bounds.h */
+	DEFINE(NR_PAGEFLAGS, __NR_PAGEFLAGS);
+	DEFINE(MAX_NR_ZONES, __MAX_NR_ZONES);
+#ifdef CONFIG_SMP
+	DEFINE(NR_CPUS_BITS, ilog2(CONFIG_NR_CPUS));
+#endif
+	DEFINE(SPINLOCK_SIZE, sizeof(spinlock_t));
+#ifdef CONFIG_LRU_GEN
+	DEFINE(LRU_GEN_WIDTH, order_base_2(MAX_NR_GENS + 1));
+	DEFINE(__LRU_REFS_WIDTH, MAX_NR_TIERS - 2);
+#else
+	DEFINE(LRU_GEN_WIDTH, 0);
+	DEFINE(__LRU_REFS_WIDTH, 0);
+#endif
+	/* End of constants */
+
+	return 0;
+}
diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig
new file mode 100644
index 000000000..2dfe1079f
--- /dev/null
+++ b/kernel/bpf/Kconfig
@@ -0,0 +1,102 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+# BPF interpreter that, for example, classic socket filters depend on.
+config BPF
+	bool
+
+# Used by archs to tell that they support BPF JIT compiler plus which
+# flavour. Only one of the two can be selected for a specific arch since
+# eBPF JIT supersedes the cBPF JIT.
+
+# Classic BPF JIT (cBPF)
+config HAVE_CBPF_JIT
+	bool
+
+# Extended BPF JIT (eBPF)
+config HAVE_EBPF_JIT
+	bool
+
+# Used by archs to tell that they want the BPF JIT compiler enabled by
+# default for kernels that were compiled with BPF JIT support.
+config ARCH_WANT_DEFAULT_BPF_JIT
+	bool
+
+menu "BPF subsystem"
+
+config BPF_SYSCALL
+	bool "Enable bpf() system call"
+	select BPF
+	select IRQ_WORK
+	select TASKS_RCU if PREEMPTION
+	select TASKS_TRACE_RCU
+	select BINARY_PRINTF
+	select NET_SOCK_MSG if NET
+	select PAGE_POOL if NET
+	default n
+	help
+	  Enable the bpf() system call that allows to manipulate BPF programs
+	  and maps via file descriptors.
+
+config BPF_JIT
+	bool "Enable BPF Just In Time compiler"
+	depends on BPF
+	depends on HAVE_CBPF_JIT || HAVE_EBPF_JIT
+	depends on MODULES
+	help
+	  BPF programs are normally handled by a BPF interpreter. This option
+	  allows the kernel to generate native code when a program is loaded
+	  into the kernel. This will significantly speed-up processing of BPF
+	  programs.
+
+	  Note, an admin should enable this feature changing:
+	  /proc/sys/net/core/bpf_jit_enable
+	  /proc/sys/net/core/bpf_jit_harden   (optional)
+	  /proc/sys/net/core/bpf_jit_kallsyms (optional)
+
+config BPF_JIT_ALWAYS_ON
+	bool "Permanently enable BPF JIT and remove BPF interpreter"
+	depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT
+	help
+	  Enables BPF JIT and removes BPF interpreter to avoid speculative
+	  execution of BPF instructions by the interpreter.
+
+	  When CONFIG_BPF_JIT_ALWAYS_ON is enabled, /proc/sys/net/core/bpf_jit_enable
+	  is permanently set to 1 and setting any other value than that will
+	  return failure.
+
+config BPF_JIT_DEFAULT_ON
+	def_bool ARCH_WANT_DEFAULT_BPF_JIT || BPF_JIT_ALWAYS_ON
+	depends on HAVE_EBPF_JIT && BPF_JIT
+
+config BPF_UNPRIV_DEFAULT_OFF
+	bool "Disable unprivileged BPF by default"
+	default y
+	depends on BPF_SYSCALL
+	help
+	  Disables unprivileged BPF by default by setting the corresponding
+	  /proc/sys/kernel/unprivileged_bpf_disabled knob to 2. An admin can
+	  still reenable it by setting it to 0 later on, or permanently
+	  disable it by setting it to 1 (from which no other transition to
+	  0 is possible anymore).
+
+	  Unprivileged BPF could be used to exploit certain potential
+	  speculative execution side-channel vulnerabilities on unmitigated
+	  affected hardware.
+
+	  If you are unsure how to answer this question, answer Y.
+
+source "kernel/bpf/preload/Kconfig"
+
+config BPF_LSM
+	bool "Enable BPF LSM Instrumentation"
+	depends on BPF_EVENTS
+	depends on BPF_SYSCALL
+	depends on SECURITY
+	depends on BPF_JIT
+	help
+	  Enables instrumentation of the security hooks with BPF programs for
+	  implementing dynamic MAC and Audit Policies.
+
+	  If you are unsure how to answer this question, answer N.
+
+endmenu # "BPF subsystem"
diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
new file mode 100644
index 000000000..341c94f20
--- /dev/null
+++ b/kernel/bpf/Makefile
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y := core.o
+ifneq ($(CONFIG_BPF_JIT_ALWAYS_ON),y)
+# ___bpf_prog_run() needs GCSE disabled on x86; see 3193c0836f203 for details
+cflags-nogcse-$(CONFIG_X86)$(CONFIG_CC_IS_GCC) := -fno-gcse
+endif
+CFLAGS_core.o += $(call cc-disable-warning, override-init) $(cflags-nogcse-yy)
+
+obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o bpf_iter.o map_iter.o task_iter.o prog_iter.o link_iter.o
+obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o bloom_filter.o
+obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o ringbuf.o
+obj-$(CONFIG_BPF_SYSCALL) += bpf_local_storage.o bpf_task_storage.o
+obj-${CONFIG_BPF_LSM}	  += bpf_inode_storage.o
+obj-$(CONFIG_BPF_SYSCALL) += disasm.o
+obj-$(CONFIG_BPF_JIT) += trampoline.o
+obj-$(CONFIG_BPF_SYSCALL) += btf.o memalloc.o
+obj-$(CONFIG_BPF_JIT) += dispatcher.o
+ifeq ($(CONFIG_NET),y)
+obj-$(CONFIG_BPF_SYSCALL) += devmap.o
+obj-$(CONFIG_BPF_SYSCALL) += cpumap.o
+obj-$(CONFIG_BPF_SYSCALL) += offload.o
+obj-$(CONFIG_BPF_SYSCALL) += net_namespace.o
+endif
+ifeq ($(CONFIG_PERF_EVENTS),y)
+obj-$(CONFIG_BPF_SYSCALL) += stackmap.o
+endif
+ifeq ($(CONFIG_CGROUPS),y)
+obj-$(CONFIG_BPF_SYSCALL) += cgroup_iter.o
+endif
+obj-$(CONFIG_CGROUP_BPF) += cgroup.o
+ifeq ($(CONFIG_INET),y)
+obj-$(CONFIG_BPF_SYSCALL) += reuseport_array.o
+endif
+ifeq ($(CONFIG_SYSFS),y)
+obj-$(CONFIG_DEBUG_INFO_BTF) += sysfs_btf.o
+endif
+ifeq ($(CONFIG_BPF_JIT),y)
+obj-$(CONFIG_BPF_SYSCALL) += bpf_struct_ops.o
+obj-${CONFIG_BPF_LSM} += bpf_lsm.o
+endif
+obj-$(CONFIG_BPF_PRELOAD) += preload/
+
+obj-$(CONFIG_BPF_SYSCALL) += relo_core.o
+$(obj)/relo_core.o: $(srctree)/tools/lib/bpf/relo_core.c FORCE
+	$(call if_changed_rule,cc_o_c)
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
new file mode 100644
index 000000000..c04e69f34
--- /dev/null
+++ b/kernel/bpf/arraymap.c
@@ -0,0 +1,1356 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ * Copyright (c) 2016,2017 Facebook
+ */
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/filter.h>
+#include <linux/perf_event.h>
+#include <uapi/linux/btf.h>
+#include <linux/rcupdate_trace.h>
+#include <linux/btf_ids.h>
+
+#include "map_in_map.h"
+
+#define ARRAY_CREATE_FLAG_MASK \
+	(BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK | \
+	 BPF_F_PRESERVE_ELEMS | BPF_F_INNER_MAP)
+
+static void bpf_array_free_percpu(struct bpf_array *array)
+{
+	int i;
+
+	for (i = 0; i < array->map.max_entries; i++) {
+		free_percpu(array->pptrs[i]);
+		cond_resched();
+	}
+}
+
+static int bpf_array_alloc_percpu(struct bpf_array *array)
+{
+	void __percpu *ptr;
+	int i;
+
+	for (i = 0; i < array->map.max_entries; i++) {
+		ptr = bpf_map_alloc_percpu(&array->map, array->elem_size, 8,
+					   GFP_USER | __GFP_NOWARN);
+		if (!ptr) {
+			bpf_array_free_percpu(array);
+			return -ENOMEM;
+		}
+		array->pptrs[i] = ptr;
+		cond_resched();
+	}
+
+	return 0;
+}
+
+/* Called from syscall */
+int array_map_alloc_check(union bpf_attr *attr)
+{
+	bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
+	int numa_node = bpf_map_attr_numa_node(attr);
+
+	/* check sanity of attributes */
+	if (attr->max_entries == 0 || attr->key_size != 4 ||
+	    attr->value_size == 0 ||
+	    attr->map_flags & ~ARRAY_CREATE_FLAG_MASK ||
+	    !bpf_map_flags_access_ok(attr->map_flags) ||
+	    (percpu && numa_node != NUMA_NO_NODE))
+		return -EINVAL;
+
+	if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
+	    attr->map_flags & (BPF_F_MMAPABLE | BPF_F_INNER_MAP))
+		return -EINVAL;
+
+	if (attr->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
+	    attr->map_flags & BPF_F_PRESERVE_ELEMS)
+		return -EINVAL;
+
+	/* avoid overflow on round_up(map->value_size) */
+	if (attr->value_size > INT_MAX)
+		return -E2BIG;
+
+	return 0;
+}
+
+static struct bpf_map *array_map_alloc(union bpf_attr *attr)
+{
+	bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
+	int numa_node = bpf_map_attr_numa_node(attr);
+	u32 elem_size, index_mask, max_entries;
+	bool bypass_spec_v1 = bpf_bypass_spec_v1();
+	u64 array_size, mask64;
+	struct bpf_array *array;
+
+	elem_size = round_up(attr->value_size, 8);
+
+	max_entries = attr->max_entries;
+
+	/* On 32 bit archs roundup_pow_of_two() with max_entries that has
+	 * upper most bit set in u32 space is undefined behavior due to
+	 * resulting 1U << 32, so do it manually here in u64 space.
+	 */
+	mask64 = fls_long(max_entries - 1);
+	mask64 = 1ULL << mask64;
+	mask64 -= 1;
+
+	index_mask = mask64;
+	if (!bypass_spec_v1) {
+		/* round up array size to nearest power of 2,
+		 * since cpu will speculate within index_mask limits
+		 */
+		max_entries = index_mask + 1;
+		/* Check for overflows. */
+		if (max_entries < attr->max_entries)
+			return ERR_PTR(-E2BIG);
+	}
+
+	array_size = sizeof(*array);
+	if (percpu) {
+		array_size += (u64) max_entries * sizeof(void *);
+	} else {
+		/* rely on vmalloc() to return page-aligned memory and
+		 * ensure array->value is exactly page-aligned
+		 */
+		if (attr->map_flags & BPF_F_MMAPABLE) {
+			array_size = PAGE_ALIGN(array_size);
+			array_size += PAGE_ALIGN((u64) max_entries * elem_size);
+		} else {
+			array_size += (u64) max_entries * elem_size;
+		}
+	}
+
+	/* allocate all map elements and zero-initialize them */
+	if (attr->map_flags & BPF_F_MMAPABLE) {
+		void *data;
+
+		/* kmalloc'ed memory can't be mmap'ed, use explicit vmalloc */
+		data = bpf_map_area_mmapable_alloc(array_size, numa_node);
+		if (!data)
+			return ERR_PTR(-ENOMEM);
+		array = data + PAGE_ALIGN(sizeof(struct bpf_array))
+			- offsetof(struct bpf_array, value);
+	} else {
+		array = bpf_map_area_alloc(array_size, numa_node);
+	}
+	if (!array)
+		return ERR_PTR(-ENOMEM);
+	array->index_mask = index_mask;
+	array->map.bypass_spec_v1 = bypass_spec_v1;
+
+	/* copy mandatory map attributes */
+	bpf_map_init_from_attr(&array->map, attr);
+	array->elem_size = elem_size;
+
+	if (percpu && bpf_array_alloc_percpu(array)) {
+		bpf_map_area_free(array);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return &array->map;
+}
+
+static void *array_map_elem_ptr(struct bpf_array* array, u32 index)
+{
+	return array->value + (u64)array->elem_size * index;
+}
+
+/* Called from syscall or from eBPF program */
+static void *array_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	u32 index = *(u32 *)key;
+
+	if (unlikely(index >= array->map.max_entries))
+		return NULL;
+
+	return array->value + (u64)array->elem_size * (index & array->index_mask);
+}
+
+static int array_map_direct_value_addr(const struct bpf_map *map, u64 *imm,
+				       u32 off)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+
+	if (map->max_entries != 1)
+		return -ENOTSUPP;
+	if (off >= map->value_size)
+		return -EINVAL;
+
+	*imm = (unsigned long)array->value;
+	return 0;
+}
+
+static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm,
+				       u32 *off)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	u64 base = (unsigned long)array->value;
+	u64 range = array->elem_size;
+
+	if (map->max_entries != 1)
+		return -ENOTSUPP;
+	if (imm < base || imm >= base + range)
+		return -ENOENT;
+
+	*off = imm - base;
+	return 0;
+}
+
+/* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
+static int array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	struct bpf_insn *insn = insn_buf;
+	u32 elem_size = array->elem_size;
+	const int ret = BPF_REG_0;
+	const int map_ptr = BPF_REG_1;
+	const int index = BPF_REG_2;
+
+	if (map->map_flags & BPF_F_INNER_MAP)
+		return -EOPNOTSUPP;
+
+	*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
+	*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
+	if (!map->bypass_spec_v1) {
+		*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 4);
+		*insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
+	} else {
+		*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 3);
+	}
+
+	if (is_power_of_2(elem_size)) {
+		*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
+	} else {
+		*insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
+	}
+	*insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
+	*insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
+	*insn++ = BPF_MOV64_IMM(ret, 0);
+	return insn - insn_buf;
+}
+
+/* Called from eBPF program */
+static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	u32 index = *(u32 *)key;
+
+	if (unlikely(index >= array->map.max_entries))
+		return NULL;
+
+	return this_cpu_ptr(array->pptrs[index & array->index_mask]);
+}
+
+static void *percpu_array_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	u32 index = *(u32 *)key;
+
+	if (cpu >= nr_cpu_ids)
+		return NULL;
+
+	if (unlikely(index >= array->map.max_entries))
+		return NULL;
+
+	return per_cpu_ptr(array->pptrs[index & array->index_mask], cpu);
+}
+
+int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	u32 index = *(u32 *)key;
+	void __percpu *pptr;
+	int cpu, off = 0;
+	u32 size;
+
+	if (unlikely(index >= array->map.max_entries))
+		return -ENOENT;
+
+	/* per_cpu areas are zero-filled and bpf programs can only
+	 * access 'value_size' of them, so copying rounded areas
+	 * will not leak any kernel data
+	 */
+	size = array->elem_size;
+	rcu_read_lock();
+	pptr = array->pptrs[index & array->index_mask];
+	for_each_possible_cpu(cpu) {
+		copy_map_value_long(map, value + off, per_cpu_ptr(pptr, cpu));
+		check_and_init_map_value(map, value + off);
+		off += size;
+	}
+	rcu_read_unlock();
+	return 0;
+}
+
+/* Called from syscall */
+static int array_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	u32 index = key ? *(u32 *)key : U32_MAX;
+	u32 *next = (u32 *)next_key;
+
+	if (index >= array->map.max_entries) {
+		*next = 0;
+		return 0;
+	}
+
+	if (index == array->map.max_entries - 1)
+		return -ENOENT;
+
+	*next = index + 1;
+	return 0;
+}
+
+static void check_and_free_fields(struct bpf_array *arr, void *val)
+{
+	if (map_value_has_timer(&arr->map))
+		bpf_timer_cancel_and_free(val + arr->map.timer_off);
+	if (map_value_has_kptrs(&arr->map))
+		bpf_map_free_kptrs(&arr->map, val);
+}
+
+/* Called from syscall or from eBPF program */
+static int array_map_update_elem(struct bpf_map *map, void *key, void *value,
+				 u64 map_flags)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	u32 index = *(u32 *)key;
+	char *val;
+
+	if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
+		/* unknown flags */
+		return -EINVAL;
+
+	if (unlikely(index >= array->map.max_entries))
+		/* all elements were pre-allocated, cannot insert a new one */
+		return -E2BIG;
+
+	if (unlikely(map_flags & BPF_NOEXIST))
+		/* all elements already exist */
+		return -EEXIST;
+
+	if (unlikely((map_flags & BPF_F_LOCK) &&
+		     !map_value_has_spin_lock(map)))
+		return -EINVAL;
+
+	if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
+		val = this_cpu_ptr(array->pptrs[index & array->index_mask]);
+		copy_map_value(map, val, value);
+		check_and_free_fields(array, val);
+	} else {
+		val = array->value +
+			(u64)array->elem_size * (index & array->index_mask);
+		if (map_flags & BPF_F_LOCK)
+			copy_map_value_locked(map, val, value, false);
+		else
+			copy_map_value(map, val, value);
+		check_and_free_fields(array, val);
+	}
+	return 0;
+}
+
+int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
+			    u64 map_flags)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	u32 index = *(u32 *)key;
+	void __percpu *pptr;
+	int cpu, off = 0;
+	u32 size;
+
+	if (unlikely(map_flags > BPF_EXIST))
+		/* unknown flags */
+		return -EINVAL;
+
+	if (unlikely(index >= array->map.max_entries))
+		/* all elements were pre-allocated, cannot insert a new one */
+		return -E2BIG;
+
+	if (unlikely(map_flags == BPF_NOEXIST))
+		/* all elements already exist */
+		return -EEXIST;
+
+	/* the user space will provide round_up(value_size, 8) bytes that
+	 * will be copied into per-cpu area. bpf programs can only access
+	 * value_size of it. During lookup the same extra bytes will be
+	 * returned or zeros which were zero-filled by percpu_alloc,
+	 * so no kernel data leaks possible
+	 */
+	size = array->elem_size;
+	rcu_read_lock();
+	pptr = array->pptrs[index & array->index_mask];
+	for_each_possible_cpu(cpu) {
+		copy_map_value_long(map, per_cpu_ptr(pptr, cpu), value + off);
+		check_and_free_fields(array, per_cpu_ptr(pptr, cpu));
+		off += size;
+	}
+	rcu_read_unlock();
+	return 0;
+}
+
+/* Called from syscall or from eBPF program */
+static int array_map_delete_elem(struct bpf_map *map, void *key)
+{
+	return -EINVAL;
+}
+
+static void *array_map_vmalloc_addr(struct bpf_array *array)
+{
+	return (void *)round_down((unsigned long)array, PAGE_SIZE);
+}
+
+static void array_map_free_timers(struct bpf_map *map)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	int i;
+
+	/* We don't reset or free kptr on uref dropping to zero. */
+	if (!map_value_has_timer(map))
+		return;
+
+	for (i = 0; i < array->map.max_entries; i++)
+		bpf_timer_cancel_and_free(array_map_elem_ptr(array, i) + map->timer_off);
+}
+
+/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
+static void array_map_free(struct bpf_map *map)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	int i;
+
+	if (map_value_has_kptrs(map)) {
+		if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
+			for (i = 0; i < array->map.max_entries; i++) {
+				void __percpu *pptr = array->pptrs[i & array->index_mask];
+				int cpu;
+
+				for_each_possible_cpu(cpu) {
+					bpf_map_free_kptrs(map, per_cpu_ptr(pptr, cpu));
+					cond_resched();
+				}
+			}
+		} else {
+			for (i = 0; i < array->map.max_entries; i++)
+				bpf_map_free_kptrs(map, array_map_elem_ptr(array, i));
+		}
+		bpf_map_free_kptr_off_tab(map);
+	}
+
+	if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
+		bpf_array_free_percpu(array);
+
+	if (array->map.map_flags & BPF_F_MMAPABLE)
+		bpf_map_area_free(array_map_vmalloc_addr(array));
+	else
+		bpf_map_area_free(array);
+}
+
+static void array_map_seq_show_elem(struct bpf_map *map, void *key,
+				    struct seq_file *m)
+{
+	void *value;
+
+	rcu_read_lock();
+
+	value = array_map_lookup_elem(map, key);
+	if (!value) {
+		rcu_read_unlock();
+		return;
+	}
+
+	if (map->btf_key_type_id)
+		seq_printf(m, "%u: ", *(u32 *)key);
+	btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
+	seq_puts(m, "\n");
+
+	rcu_read_unlock();
+}
+
+static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
+					   struct seq_file *m)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	u32 index = *(u32 *)key;
+	void __percpu *pptr;
+	int cpu;
+
+	rcu_read_lock();
+
+	seq_printf(m, "%u: {\n", *(u32 *)key);
+	pptr = array->pptrs[index & array->index_mask];
+	for_each_possible_cpu(cpu) {
+		seq_printf(m, "\tcpu%d: ", cpu);
+		btf_type_seq_show(map->btf, map->btf_value_type_id,
+				  per_cpu_ptr(pptr, cpu), m);
+		seq_puts(m, "\n");
+	}
+	seq_puts(m, "}\n");
+
+	rcu_read_unlock();
+}
+
+static int array_map_check_btf(const struct bpf_map *map,
+			       const struct btf *btf,
+			       const struct btf_type *key_type,
+			       const struct btf_type *value_type)
+{
+	u32 int_data;
+
+	/* One exception for keyless BTF: .bss/.data/.rodata map */
+	if (btf_type_is_void(key_type)) {
+		if (map->map_type != BPF_MAP_TYPE_ARRAY ||
+		    map->max_entries != 1)
+			return -EINVAL;
+
+		if (BTF_INFO_KIND(value_type->info) != BTF_KIND_DATASEC)
+			return -EINVAL;
+
+		return 0;
+	}
+
+	if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
+		return -EINVAL;
+
+	int_data = *(u32 *)(key_type + 1);
+	/* bpf array can only take a u32 key. This check makes sure
+	 * that the btf matches the attr used during map_create.
+	 */
+	if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int array_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	pgoff_t pgoff = PAGE_ALIGN(sizeof(*array)) >> PAGE_SHIFT;
+
+	if (!(map->map_flags & BPF_F_MMAPABLE))
+		return -EINVAL;
+
+	if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) >
+	    PAGE_ALIGN((u64)array->map.max_entries * array->elem_size))
+		return -EINVAL;
+
+	return remap_vmalloc_range(vma, array_map_vmalloc_addr(array),
+				   vma->vm_pgoff + pgoff);
+}
+
+static bool array_map_meta_equal(const struct bpf_map *meta0,
+				 const struct bpf_map *meta1)
+{
+	if (!bpf_map_meta_equal(meta0, meta1))
+		return false;
+	return meta0->map_flags & BPF_F_INNER_MAP ? true :
+	       meta0->max_entries == meta1->max_entries;
+}
+
+struct bpf_iter_seq_array_map_info {
+	struct bpf_map *map;
+	void *percpu_value_buf;
+	u32 index;
+};
+
+static void *bpf_array_map_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct bpf_iter_seq_array_map_info *info = seq->private;
+	struct bpf_map *map = info->map;
+	struct bpf_array *array;
+	u32 index;
+
+	if (info->index >= map->max_entries)
+		return NULL;
+
+	if (*pos == 0)
+		++*pos;
+	array = container_of(map, struct bpf_array, map);
+	index = info->index & array->index_mask;
+	if (info->percpu_value_buf)
+	       return array->pptrs[index];
+	return array_map_elem_ptr(array, index);
+}
+
+static void *bpf_array_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct bpf_iter_seq_array_map_info *info = seq->private;
+	struct bpf_map *map = info->map;
+	struct bpf_array *array;
+	u32 index;
+
+	++*pos;
+	++info->index;
+	if (info->index >= map->max_entries)
+		return NULL;
+
+	array = container_of(map, struct bpf_array, map);
+	index = info->index & array->index_mask;
+	if (info->percpu_value_buf)
+	       return array->pptrs[index];
+	return array_map_elem_ptr(array, index);
+}
+
+static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
+{
+	struct bpf_iter_seq_array_map_info *info = seq->private;
+	struct bpf_iter__bpf_map_elem ctx = {};
+	struct bpf_map *map = info->map;
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	struct bpf_iter_meta meta;
+	struct bpf_prog *prog;
+	int off = 0, cpu = 0;
+	void __percpu **pptr;
+	u32 size;
+
+	meta.seq = seq;
+	prog = bpf_iter_get_info(&meta, v == NULL);
+	if (!prog)
+		return 0;
+
+	ctx.meta = &meta;
+	ctx.map = info->map;
+	if (v) {
+		ctx.key = &info->index;
+
+		if (!info->percpu_value_buf) {
+			ctx.value = v;
+		} else {
+			pptr = v;
+			size = array->elem_size;
+			for_each_possible_cpu(cpu) {
+				copy_map_value_long(map, info->percpu_value_buf + off,
+						    per_cpu_ptr(pptr, cpu));
+				check_and_init_map_value(map, info->percpu_value_buf + off);
+				off += size;
+			}
+			ctx.value = info->percpu_value_buf;
+		}
+	}
+
+	return bpf_iter_run_prog(prog, &ctx);
+}
+
+static int bpf_array_map_seq_show(struct seq_file *seq, void *v)
+{
+	return __bpf_array_map_seq_show(seq, v);
+}
+
+static void bpf_array_map_seq_stop(struct seq_file *seq, void *v)
+{
+	if (!v)
+		(void)__bpf_array_map_seq_show(seq, NULL);
+}
+
+static int bpf_iter_init_array_map(void *priv_data,
+				   struct bpf_iter_aux_info *aux)
+{
+	struct bpf_iter_seq_array_map_info *seq_info = priv_data;
+	struct bpf_map *map = aux->map;
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	void *value_buf;
+	u32 buf_size;
+
+	if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
+		buf_size = array->elem_size * num_possible_cpus();
+		value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
+		if (!value_buf)
+			return -ENOMEM;
+
+		seq_info->percpu_value_buf = value_buf;
+	}
+
+	/* bpf_iter_attach_map() acquires a map uref, and the uref may be
+	 * released before or in the middle of iterating map elements, so
+	 * acquire an extra map uref for iterator.
+	 */
+	bpf_map_inc_with_uref(map);
+	seq_info->map = map;
+	return 0;
+}
+
+static void bpf_iter_fini_array_map(void *priv_data)
+{
+	struct bpf_iter_seq_array_map_info *seq_info = priv_data;
+
+	bpf_map_put_with_uref(seq_info->map);
+	kfree(seq_info->percpu_value_buf);
+}
+
+static const struct seq_operations bpf_array_map_seq_ops = {
+	.start	= bpf_array_map_seq_start,
+	.next	= bpf_array_map_seq_next,
+	.stop	= bpf_array_map_seq_stop,
+	.show	= bpf_array_map_seq_show,
+};
+
+static const struct bpf_iter_seq_info iter_seq_info = {
+	.seq_ops		= &bpf_array_map_seq_ops,
+	.init_seq_private	= bpf_iter_init_array_map,
+	.fini_seq_private	= bpf_iter_fini_array_map,
+	.seq_priv_size		= sizeof(struct bpf_iter_seq_array_map_info),
+};
+
+static int bpf_for_each_array_elem(struct bpf_map *map, bpf_callback_t callback_fn,
+				   void *callback_ctx, u64 flags)
+{
+	u32 i, key, num_elems = 0;
+	struct bpf_array *array;
+	bool is_percpu;
+	u64 ret = 0;
+	void *val;
+
+	if (flags != 0)
+		return -EINVAL;
+
+	is_percpu = map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
+	array = container_of(map, struct bpf_array, map);
+	if (is_percpu)
+		migrate_disable();
+	for (i = 0; i < map->max_entries; i++) {
+		if (is_percpu)
+			val = this_cpu_ptr(array->pptrs[i]);
+		else
+			val = array_map_elem_ptr(array, i);
+		num_elems++;
+		key = i;
+		ret = callback_fn((u64)(long)map, (u64)(long)&key,
+				  (u64)(long)val, (u64)(long)callback_ctx, 0);
+		/* return value: 0 - continue, 1 - stop and return */
+		if (ret)
+			break;
+	}
+
+	if (is_percpu)
+		migrate_enable();
+	return num_elems;
+}
+
+BTF_ID_LIST_SINGLE(array_map_btf_ids, struct, bpf_array)
+const struct bpf_map_ops array_map_ops = {
+	.map_meta_equal = array_map_meta_equal,
+	.map_alloc_check = array_map_alloc_check,
+	.map_alloc = array_map_alloc,
+	.map_free = array_map_free,
+	.map_get_next_key = array_map_get_next_key,
+	.map_release_uref = array_map_free_timers,
+	.map_lookup_elem = array_map_lookup_elem,
+	.map_update_elem = array_map_update_elem,
+	.map_delete_elem = array_map_delete_elem,
+	.map_gen_lookup = array_map_gen_lookup,
+	.map_direct_value_addr = array_map_direct_value_addr,
+	.map_direct_value_meta = array_map_direct_value_meta,
+	.map_mmap = array_map_mmap,
+	.map_seq_show_elem = array_map_seq_show_elem,
+	.map_check_btf = array_map_check_btf,
+	.map_lookup_batch = generic_map_lookup_batch,
+	.map_update_batch = generic_map_update_batch,
+	.map_set_for_each_callback_args = map_set_for_each_callback_args,
+	.map_for_each_callback = bpf_for_each_array_elem,
+	.map_btf_id = &array_map_btf_ids[0],
+	.iter_seq_info = &iter_seq_info,
+};
+
+const struct bpf_map_ops percpu_array_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = array_map_alloc_check,
+	.map_alloc = array_map_alloc,
+	.map_free = array_map_free,
+	.map_get_next_key = array_map_get_next_key,
+	.map_lookup_elem = percpu_array_map_lookup_elem,
+	.map_update_elem = array_map_update_elem,
+	.map_delete_elem = array_map_delete_elem,
+	.map_lookup_percpu_elem = percpu_array_map_lookup_percpu_elem,
+	.map_seq_show_elem = percpu_array_map_seq_show_elem,
+	.map_check_btf = array_map_check_btf,
+	.map_lookup_batch = generic_map_lookup_batch,
+	.map_update_batch = generic_map_update_batch,
+	.map_set_for_each_callback_args = map_set_for_each_callback_args,
+	.map_for_each_callback = bpf_for_each_array_elem,
+	.map_btf_id = &array_map_btf_ids[0],
+	.iter_seq_info = &iter_seq_info,
+};
+
+static int fd_array_map_alloc_check(union bpf_attr *attr)
+{
+	/* only file descriptors can be stored in this type of map */
+	if (attr->value_size != sizeof(u32))
+		return -EINVAL;
+	/* Program read-only/write-only not supported for special maps yet. */
+	if (attr->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG))
+		return -EINVAL;
+	return array_map_alloc_check(attr);
+}
+
+static void fd_array_map_free(struct bpf_map *map)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	int i;
+
+	/* make sure it's empty */
+	for (i = 0; i < array->map.max_entries; i++)
+		BUG_ON(array->ptrs[i] != NULL);
+
+	bpf_map_area_free(array);
+}
+
+static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
+/* only called from syscall */
+int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
+{
+	void **elem, *ptr;
+	int ret =  0;
+
+	if (!map->ops->map_fd_sys_lookup_elem)
+		return -ENOTSUPP;
+
+	rcu_read_lock();
+	elem = array_map_lookup_elem(map, key);
+	if (elem && (ptr = READ_ONCE(*elem)))
+		*value = map->ops->map_fd_sys_lookup_elem(ptr);
+	else
+		ret = -ENOENT;
+	rcu_read_unlock();
+
+	return ret;
+}
+
+/* only called from syscall */
+int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
+				 void *key, void *value, u64 map_flags)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	void *new_ptr, *old_ptr;
+	u32 index = *(u32 *)key, ufd;
+
+	if (map_flags != BPF_ANY)
+		return -EINVAL;
+
+	if (index >= array->map.max_entries)
+		return -E2BIG;
+
+	ufd = *(u32 *)value;
+	new_ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
+	if (IS_ERR(new_ptr))
+		return PTR_ERR(new_ptr);
+
+	if (map->ops->map_poke_run) {
+		mutex_lock(&array->aux->poke_mutex);
+		old_ptr = xchg(array->ptrs + index, new_ptr);
+		map->ops->map_poke_run(map, index, old_ptr, new_ptr);
+		mutex_unlock(&array->aux->poke_mutex);
+	} else {
+		old_ptr = xchg(array->ptrs + index, new_ptr);
+	}
+
+	if (old_ptr)
+		map->ops->map_fd_put_ptr(map, old_ptr, true);
+	return 0;
+}
+
+static int fd_array_map_delete_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	void *old_ptr;
+	u32 index = *(u32 *)key;
+
+	if (index >= array->map.max_entries)
+		return -E2BIG;
+
+	if (map->ops->map_poke_run) {
+		mutex_lock(&array->aux->poke_mutex);
+		old_ptr = xchg(array->ptrs + index, NULL);
+		map->ops->map_poke_run(map, index, old_ptr, NULL);
+		mutex_unlock(&array->aux->poke_mutex);
+	} else {
+		old_ptr = xchg(array->ptrs + index, NULL);
+	}
+
+	if (old_ptr) {
+		map->ops->map_fd_put_ptr(map, old_ptr, true);
+		return 0;
+	} else {
+		return -ENOENT;
+	}
+}
+
+static void *prog_fd_array_get_ptr(struct bpf_map *map,
+				   struct file *map_file, int fd)
+{
+	struct bpf_prog *prog = bpf_prog_get(fd);
+
+	if (IS_ERR(prog))
+		return prog;
+
+	if (!bpf_prog_map_compatible(map, prog)) {
+		bpf_prog_put(prog);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return prog;
+}
+
+static void prog_fd_array_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
+{
+	/* bpf_prog is freed after one RCU or tasks trace grace period */
+	bpf_prog_put(ptr);
+}
+
+static u32 prog_fd_array_sys_lookup_elem(void *ptr)
+{
+	return ((struct bpf_prog *)ptr)->aux->id;
+}
+
+/* decrement refcnt of all bpf_progs that are stored in this map */
+static void bpf_fd_array_map_clear(struct bpf_map *map)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	int i;
+
+	for (i = 0; i < array->map.max_entries; i++)
+		fd_array_map_delete_elem(map, &i);
+}
+
+static void prog_array_map_seq_show_elem(struct bpf_map *map, void *key,
+					 struct seq_file *m)
+{
+	void **elem, *ptr;
+	u32 prog_id;
+
+	rcu_read_lock();
+
+	elem = array_map_lookup_elem(map, key);
+	if (elem) {
+		ptr = READ_ONCE(*elem);
+		if (ptr) {
+			seq_printf(m, "%u: ", *(u32 *)key);
+			prog_id = prog_fd_array_sys_lookup_elem(ptr);
+			btf_type_seq_show(map->btf, map->btf_value_type_id,
+					  &prog_id, m);
+			seq_puts(m, "\n");
+		}
+	}
+
+	rcu_read_unlock();
+}
+
+struct prog_poke_elem {
+	struct list_head list;
+	struct bpf_prog_aux *aux;
+};
+
+static int prog_array_map_poke_track(struct bpf_map *map,
+				     struct bpf_prog_aux *prog_aux)
+{
+	struct prog_poke_elem *elem;
+	struct bpf_array_aux *aux;
+	int ret = 0;
+
+	aux = container_of(map, struct bpf_array, map)->aux;
+	mutex_lock(&aux->poke_mutex);
+	list_for_each_entry(elem, &aux->poke_progs, list) {
+		if (elem->aux == prog_aux)
+			goto out;
+	}
+
+	elem = kmalloc(sizeof(*elem), GFP_KERNEL);
+	if (!elem) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	INIT_LIST_HEAD(&elem->list);
+	/* We must track the program's aux info at this point in time
+	 * since the program pointer itself may not be stable yet, see
+	 * also comment in prog_array_map_poke_run().
+	 */
+	elem->aux = prog_aux;
+
+	list_add_tail(&elem->list, &aux->poke_progs);
+out:
+	mutex_unlock(&aux->poke_mutex);
+	return ret;
+}
+
+static void prog_array_map_poke_untrack(struct bpf_map *map,
+					struct bpf_prog_aux *prog_aux)
+{
+	struct prog_poke_elem *elem, *tmp;
+	struct bpf_array_aux *aux;
+
+	aux = container_of(map, struct bpf_array, map)->aux;
+	mutex_lock(&aux->poke_mutex);
+	list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
+		if (elem->aux == prog_aux) {
+			list_del_init(&elem->list);
+			kfree(elem);
+			break;
+		}
+	}
+	mutex_unlock(&aux->poke_mutex);
+}
+
+void __weak bpf_arch_poke_desc_update(struct bpf_jit_poke_descriptor *poke,
+				      struct bpf_prog *new, struct bpf_prog *old)
+{
+	WARN_ON_ONCE(1);
+}
+
+static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
+				    struct bpf_prog *old,
+				    struct bpf_prog *new)
+{
+	struct prog_poke_elem *elem;
+	struct bpf_array_aux *aux;
+
+	aux = container_of(map, struct bpf_array, map)->aux;
+	WARN_ON_ONCE(!mutex_is_locked(&aux->poke_mutex));
+
+	list_for_each_entry(elem, &aux->poke_progs, list) {
+		struct bpf_jit_poke_descriptor *poke;
+		int i;
+
+		for (i = 0; i < elem->aux->size_poke_tab; i++) {
+			poke = &elem->aux->poke_tab[i];
+
+			/* Few things to be aware of:
+			 *
+			 * 1) We can only ever access aux in this context, but
+			 *    not aux->prog since it might not be stable yet and
+			 *    there could be danger of use after free otherwise.
+			 * 2) Initially when we start tracking aux, the program
+			 *    is not JITed yet and also does not have a kallsyms
+			 *    entry. We skip these as poke->tailcall_target_stable
+			 *    is not active yet. The JIT will do the final fixup
+			 *    before setting it stable. The various
+			 *    poke->tailcall_target_stable are successively
+			 *    activated, so tail call updates can arrive from here
+			 *    while JIT is still finishing its final fixup for
+			 *    non-activated poke entries.
+			 * 3) Also programs reaching refcount of zero while patching
+			 *    is in progress is okay since we're protected under
+			 *    poke_mutex and untrack the programs before the JIT
+			 *    buffer is freed.
+			 */
+			if (!READ_ONCE(poke->tailcall_target_stable))
+				continue;
+			if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
+				continue;
+			if (poke->tail_call.map != map ||
+			    poke->tail_call.key != key)
+				continue;
+
+			bpf_arch_poke_desc_update(poke, new, old);
+		}
+	}
+}
+
+static void prog_array_map_clear_deferred(struct work_struct *work)
+{
+	struct bpf_map *map = container_of(work, struct bpf_array_aux,
+					   work)->map;
+	bpf_fd_array_map_clear(map);
+	bpf_map_put(map);
+}
+
+static void prog_array_map_clear(struct bpf_map *map)
+{
+	struct bpf_array_aux *aux = container_of(map, struct bpf_array,
+						 map)->aux;
+	bpf_map_inc(map);
+	schedule_work(&aux->work);
+}
+
+static struct bpf_map *prog_array_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_array_aux *aux;
+	struct bpf_map *map;
+
+	aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT);
+	if (!aux)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_WORK(&aux->work, prog_array_map_clear_deferred);
+	INIT_LIST_HEAD(&aux->poke_progs);
+	mutex_init(&aux->poke_mutex);
+
+	map = array_map_alloc(attr);
+	if (IS_ERR(map)) {
+		kfree(aux);
+		return map;
+	}
+
+	container_of(map, struct bpf_array, map)->aux = aux;
+	aux->map = map;
+
+	return map;
+}
+
+static void prog_array_map_free(struct bpf_map *map)
+{
+	struct prog_poke_elem *elem, *tmp;
+	struct bpf_array_aux *aux;
+
+	aux = container_of(map, struct bpf_array, map)->aux;
+	list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
+		list_del_init(&elem->list);
+		kfree(elem);
+	}
+	kfree(aux);
+	fd_array_map_free(map);
+}
+
+/* prog_array->aux->{type,jited} is a runtime binding.
+ * Doing static check alone in the verifier is not enough.
+ * Thus, prog_array_map cannot be used as an inner_map
+ * and map_meta_equal is not implemented.
+ */
+const struct bpf_map_ops prog_array_map_ops = {
+	.map_alloc_check = fd_array_map_alloc_check,
+	.map_alloc = prog_array_map_alloc,
+	.map_free = prog_array_map_free,
+	.map_poke_track = prog_array_map_poke_track,
+	.map_poke_untrack = prog_array_map_poke_untrack,
+	.map_poke_run = prog_array_map_poke_run,
+	.map_get_next_key = array_map_get_next_key,
+	.map_lookup_elem = fd_array_map_lookup_elem,
+	.map_delete_elem = fd_array_map_delete_elem,
+	.map_fd_get_ptr = prog_fd_array_get_ptr,
+	.map_fd_put_ptr = prog_fd_array_put_ptr,
+	.map_fd_sys_lookup_elem = prog_fd_array_sys_lookup_elem,
+	.map_release_uref = prog_array_map_clear,
+	.map_seq_show_elem = prog_array_map_seq_show_elem,
+	.map_btf_id = &array_map_btf_ids[0],
+};
+
+static struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
+						   struct file *map_file)
+{
+	struct bpf_event_entry *ee;
+
+	ee = kzalloc(sizeof(*ee), GFP_ATOMIC);
+	if (ee) {
+		ee->event = perf_file->private_data;
+		ee->perf_file = perf_file;
+		ee->map_file = map_file;
+	}
+
+	return ee;
+}
+
+static void __bpf_event_entry_free(struct rcu_head *rcu)
+{
+	struct bpf_event_entry *ee;
+
+	ee = container_of(rcu, struct bpf_event_entry, rcu);
+	fput(ee->perf_file);
+	kfree(ee);
+}
+
+static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
+{
+	call_rcu(&ee->rcu, __bpf_event_entry_free);
+}
+
+static void *perf_event_fd_array_get_ptr(struct bpf_map *map,
+					 struct file *map_file, int fd)
+{
+	struct bpf_event_entry *ee;
+	struct perf_event *event;
+	struct file *perf_file;
+	u64 value;
+
+	perf_file = perf_event_get(fd);
+	if (IS_ERR(perf_file))
+		return perf_file;
+
+	ee = ERR_PTR(-EOPNOTSUPP);
+	event = perf_file->private_data;
+	if (perf_event_read_local(event, &value, NULL, NULL) == -EOPNOTSUPP)
+		goto err_out;
+
+	ee = bpf_event_entry_gen(perf_file, map_file);
+	if (ee)
+		return ee;
+	ee = ERR_PTR(-ENOMEM);
+err_out:
+	fput(perf_file);
+	return ee;
+}
+
+static void perf_event_fd_array_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
+{
+	/* bpf_perf_event is freed after one RCU grace period */
+	bpf_event_entry_free_rcu(ptr);
+}
+
+static void perf_event_fd_array_release(struct bpf_map *map,
+					struct file *map_file)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	struct bpf_event_entry *ee;
+	int i;
+
+	if (map->map_flags & BPF_F_PRESERVE_ELEMS)
+		return;
+
+	rcu_read_lock();
+	for (i = 0; i < array->map.max_entries; i++) {
+		ee = READ_ONCE(array->ptrs[i]);
+		if (ee && ee->map_file == map_file)
+			fd_array_map_delete_elem(map, &i);
+	}
+	rcu_read_unlock();
+}
+
+static void perf_event_fd_array_map_free(struct bpf_map *map)
+{
+	if (map->map_flags & BPF_F_PRESERVE_ELEMS)
+		bpf_fd_array_map_clear(map);
+	fd_array_map_free(map);
+}
+
+const struct bpf_map_ops perf_event_array_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = fd_array_map_alloc_check,
+	.map_alloc = array_map_alloc,
+	.map_free = perf_event_fd_array_map_free,
+	.map_get_next_key = array_map_get_next_key,
+	.map_lookup_elem = fd_array_map_lookup_elem,
+	.map_delete_elem = fd_array_map_delete_elem,
+	.map_fd_get_ptr = perf_event_fd_array_get_ptr,
+	.map_fd_put_ptr = perf_event_fd_array_put_ptr,
+	.map_release = perf_event_fd_array_release,
+	.map_check_btf = map_check_no_btf,
+	.map_btf_id = &array_map_btf_ids[0],
+};
+
+#ifdef CONFIG_CGROUPS
+static void *cgroup_fd_array_get_ptr(struct bpf_map *map,
+				     struct file *map_file /* not used */,
+				     int fd)
+{
+	return cgroup_get_from_fd(fd);
+}
+
+static void cgroup_fd_array_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
+{
+	/* cgroup_put free cgrp after a rcu grace period */
+	cgroup_put(ptr);
+}
+
+static void cgroup_fd_array_free(struct bpf_map *map)
+{
+	bpf_fd_array_map_clear(map);
+	fd_array_map_free(map);
+}
+
+const struct bpf_map_ops cgroup_array_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = fd_array_map_alloc_check,
+	.map_alloc = array_map_alloc,
+	.map_free = cgroup_fd_array_free,
+	.map_get_next_key = array_map_get_next_key,
+	.map_lookup_elem = fd_array_map_lookup_elem,
+	.map_delete_elem = fd_array_map_delete_elem,
+	.map_fd_get_ptr = cgroup_fd_array_get_ptr,
+	.map_fd_put_ptr = cgroup_fd_array_put_ptr,
+	.map_check_btf = map_check_no_btf,
+	.map_btf_id = &array_map_btf_ids[0],
+};
+#endif
+
+static struct bpf_map *array_of_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_map *map, *inner_map_meta;
+
+	inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
+	if (IS_ERR(inner_map_meta))
+		return inner_map_meta;
+
+	map = array_map_alloc(attr);
+	if (IS_ERR(map)) {
+		bpf_map_meta_free(inner_map_meta);
+		return map;
+	}
+
+	map->inner_map_meta = inner_map_meta;
+
+	return map;
+}
+
+static void array_of_map_free(struct bpf_map *map)
+{
+	/* map->inner_map_meta is only accessed by syscall which
+	 * is protected by fdget/fdput.
+	 */
+	bpf_map_meta_free(map->inner_map_meta);
+	bpf_fd_array_map_clear(map);
+	fd_array_map_free(map);
+}
+
+static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_map **inner_map = array_map_lookup_elem(map, key);
+
+	if (!inner_map)
+		return NULL;
+
+	return READ_ONCE(*inner_map);
+}
+
+static int array_of_map_gen_lookup(struct bpf_map *map,
+				   struct bpf_insn *insn_buf)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	u32 elem_size = array->elem_size;
+	struct bpf_insn *insn = insn_buf;
+	const int ret = BPF_REG_0;
+	const int map_ptr = BPF_REG_1;
+	const int index = BPF_REG_2;
+
+	*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
+	*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
+	if (!map->bypass_spec_v1) {
+		*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 6);
+		*insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
+	} else {
+		*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
+	}
+	if (is_power_of_2(elem_size))
+		*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
+	else
+		*insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
+	*insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
+	*insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
+	*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
+	*insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
+	*insn++ = BPF_MOV64_IMM(ret, 0);
+
+	return insn - insn_buf;
+}
+
+const struct bpf_map_ops array_of_maps_map_ops = {
+	.map_alloc_check = fd_array_map_alloc_check,
+	.map_alloc = array_of_map_alloc,
+	.map_free = array_of_map_free,
+	.map_get_next_key = array_map_get_next_key,
+	.map_lookup_elem = array_of_map_lookup_elem,
+	.map_delete_elem = fd_array_map_delete_elem,
+	.map_fd_get_ptr = bpf_map_fd_get_ptr,
+	.map_fd_put_ptr = bpf_map_fd_put_ptr,
+	.map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
+	.map_gen_lookup = array_of_map_gen_lookup,
+	.map_lookup_batch = generic_map_lookup_batch,
+	.map_update_batch = generic_map_update_batch,
+	.map_check_btf = map_check_no_btf,
+	.map_btf_id = &array_map_btf_ids[0],
+};
diff --git a/kernel/bpf/bloom_filter.c b/kernel/bpf/bloom_filter.c
new file mode 100644
index 000000000..48ee75084
--- /dev/null
+++ b/kernel/bpf/bloom_filter.c
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+
+#include <linux/bitmap.h>
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/err.h>
+#include <linux/jhash.h>
+#include <linux/random.h>
+#include <linux/btf_ids.h>
+
+#define BLOOM_CREATE_FLAG_MASK \
+	(BPF_F_NUMA_NODE | BPF_F_ZERO_SEED | BPF_F_ACCESS_MASK)
+
+struct bpf_bloom_filter {
+	struct bpf_map map;
+	u32 bitset_mask;
+	u32 hash_seed;
+	/* If the size of the values in the bloom filter is u32 aligned,
+	 * then it is more performant to use jhash2 as the underlying hash
+	 * function, else we use jhash. This tracks the number of u32s
+	 * in an u32-aligned value size. If the value size is not u32 aligned,
+	 * this will be 0.
+	 */
+	u32 aligned_u32_count;
+	u32 nr_hash_funcs;
+	unsigned long bitset[];
+};
+
+static u32 hash(struct bpf_bloom_filter *bloom, void *value,
+		u32 value_size, u32 index)
+{
+	u32 h;
+
+	if (bloom->aligned_u32_count)
+		h = jhash2(value, bloom->aligned_u32_count,
+			   bloom->hash_seed + index);
+	else
+		h = jhash(value, value_size, bloom->hash_seed + index);
+
+	return h & bloom->bitset_mask;
+}
+
+static int bloom_map_peek_elem(struct bpf_map *map, void *value)
+{
+	struct bpf_bloom_filter *bloom =
+		container_of(map, struct bpf_bloom_filter, map);
+	u32 i, h;
+
+	for (i = 0; i < bloom->nr_hash_funcs; i++) {
+		h = hash(bloom, value, map->value_size, i);
+		if (!test_bit(h, bloom->bitset))
+			return -ENOENT;
+	}
+
+	return 0;
+}
+
+static int bloom_map_push_elem(struct bpf_map *map, void *value, u64 flags)
+{
+	struct bpf_bloom_filter *bloom =
+		container_of(map, struct bpf_bloom_filter, map);
+	u32 i, h;
+
+	if (flags != BPF_ANY)
+		return -EINVAL;
+
+	for (i = 0; i < bloom->nr_hash_funcs; i++) {
+		h = hash(bloom, value, map->value_size, i);
+		set_bit(h, bloom->bitset);
+	}
+
+	return 0;
+}
+
+static int bloom_map_pop_elem(struct bpf_map *map, void *value)
+{
+	return -EOPNOTSUPP;
+}
+
+static int bloom_map_delete_elem(struct bpf_map *map, void *value)
+{
+	return -EOPNOTSUPP;
+}
+
+static int bloom_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
+{
+	return -EOPNOTSUPP;
+}
+
+static struct bpf_map *bloom_map_alloc(union bpf_attr *attr)
+{
+	u32 bitset_bytes, bitset_mask, nr_hash_funcs, nr_bits;
+	int numa_node = bpf_map_attr_numa_node(attr);
+	struct bpf_bloom_filter *bloom;
+
+	if (!bpf_capable())
+		return ERR_PTR(-EPERM);
+
+	if (attr->key_size != 0 || attr->value_size == 0 ||
+	    attr->max_entries == 0 ||
+	    attr->map_flags & ~BLOOM_CREATE_FLAG_MASK ||
+	    !bpf_map_flags_access_ok(attr->map_flags) ||
+	    /* The lower 4 bits of map_extra (0xF) specify the number
+	     * of hash functions
+	     */
+	    (attr->map_extra & ~0xF))
+		return ERR_PTR(-EINVAL);
+
+	nr_hash_funcs = attr->map_extra;
+	if (nr_hash_funcs == 0)
+		/* Default to using 5 hash functions if unspecified */
+		nr_hash_funcs = 5;
+
+	/* For the bloom filter, the optimal bit array size that minimizes the
+	 * false positive probability is n * k / ln(2) where n is the number of
+	 * expected entries in the bloom filter and k is the number of hash
+	 * functions. We use 7 / 5 to approximate 1 / ln(2).
+	 *
+	 * We round this up to the nearest power of two to enable more efficient
+	 * hashing using bitmasks. The bitmask will be the bit array size - 1.
+	 *
+	 * If this overflows a u32, the bit array size will have 2^32 (4
+	 * GB) bits.
+	 */
+	if (check_mul_overflow(attr->max_entries, nr_hash_funcs, &nr_bits) ||
+	    check_mul_overflow(nr_bits / 5, (u32)7, &nr_bits) ||
+	    nr_bits > (1UL << 31)) {
+		/* The bit array size is 2^32 bits but to avoid overflowing the
+		 * u32, we use U32_MAX, which will round up to the equivalent
+		 * number of bytes
+		 */
+		bitset_bytes = BITS_TO_BYTES(U32_MAX);
+		bitset_mask = U32_MAX;
+	} else {
+		if (nr_bits <= BITS_PER_LONG)
+			nr_bits = BITS_PER_LONG;
+		else
+			nr_bits = roundup_pow_of_two(nr_bits);
+		bitset_bytes = BITS_TO_BYTES(nr_bits);
+		bitset_mask = nr_bits - 1;
+	}
+
+	bitset_bytes = roundup(bitset_bytes, sizeof(unsigned long));
+	bloom = bpf_map_area_alloc(sizeof(*bloom) + bitset_bytes, numa_node);
+
+	if (!bloom)
+		return ERR_PTR(-ENOMEM);
+
+	bpf_map_init_from_attr(&bloom->map, attr);
+
+	bloom->nr_hash_funcs = nr_hash_funcs;
+	bloom->bitset_mask = bitset_mask;
+
+	/* Check whether the value size is u32-aligned */
+	if ((attr->value_size & (sizeof(u32) - 1)) == 0)
+		bloom->aligned_u32_count =
+			attr->value_size / sizeof(u32);
+
+	if (!(attr->map_flags & BPF_F_ZERO_SEED))
+		bloom->hash_seed = get_random_u32();
+
+	return &bloom->map;
+}
+
+static void bloom_map_free(struct bpf_map *map)
+{
+	struct bpf_bloom_filter *bloom =
+		container_of(map, struct bpf_bloom_filter, map);
+
+	bpf_map_area_free(bloom);
+}
+
+static void *bloom_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	/* The eBPF program should use map_peek_elem instead */
+	return ERR_PTR(-EINVAL);
+}
+
+static int bloom_map_update_elem(struct bpf_map *map, void *key,
+				 void *value, u64 flags)
+{
+	/* The eBPF program should use map_push_elem instead */
+	return -EINVAL;
+}
+
+static int bloom_map_check_btf(const struct bpf_map *map,
+			       const struct btf *btf,
+			       const struct btf_type *key_type,
+			       const struct btf_type *value_type)
+{
+	/* Bloom filter maps are keyless */
+	return btf_type_is_void(key_type) ? 0 : -EINVAL;
+}
+
+BTF_ID_LIST_SINGLE(bpf_bloom_map_btf_ids, struct, bpf_bloom_filter)
+const struct bpf_map_ops bloom_filter_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc = bloom_map_alloc,
+	.map_free = bloom_map_free,
+	.map_get_next_key = bloom_map_get_next_key,
+	.map_push_elem = bloom_map_push_elem,
+	.map_peek_elem = bloom_map_peek_elem,
+	.map_pop_elem = bloom_map_pop_elem,
+	.map_lookup_elem = bloom_map_lookup_elem,
+	.map_update_elem = bloom_map_update_elem,
+	.map_delete_elem = bloom_map_delete_elem,
+	.map_check_btf = bloom_map_check_btf,
+	.map_btf_id = &bpf_bloom_map_btf_ids[0],
+};
diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c
new file mode 100644
index 000000000..5f7683b19
--- /dev/null
+++ b/kernel/bpf/bpf_inode_storage.c
@@ -0,0 +1,284 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019 Facebook
+ * Copyright 2020 Google LLC.
+ */
+
+#include <linux/rculist.h>
+#include <linux/list.h>
+#include <linux/hash.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/bpf.h>
+#include <linux/bpf_local_storage.h>
+#include <net/sock.h>
+#include <uapi/linux/sock_diag.h>
+#include <uapi/linux/btf.h>
+#include <linux/bpf_lsm.h>
+#include <linux/btf_ids.h>
+#include <linux/fdtable.h>
+#include <linux/rcupdate_trace.h>
+
+DEFINE_BPF_STORAGE_CACHE(inode_cache);
+
+static struct bpf_local_storage __rcu **
+inode_storage_ptr(void *owner)
+{
+	struct inode *inode = owner;
+	struct bpf_storage_blob *bsb;
+
+	bsb = bpf_inode(inode);
+	if (!bsb)
+		return NULL;
+	return &bsb->storage;
+}
+
+static struct bpf_local_storage_data *inode_storage_lookup(struct inode *inode,
+							   struct bpf_map *map,
+							   bool cacheit_lockit)
+{
+	struct bpf_local_storage *inode_storage;
+	struct bpf_local_storage_map *smap;
+	struct bpf_storage_blob *bsb;
+
+	bsb = bpf_inode(inode);
+	if (!bsb)
+		return NULL;
+
+	inode_storage =
+		rcu_dereference_check(bsb->storage, bpf_rcu_lock_held());
+	if (!inode_storage)
+		return NULL;
+
+	smap = (struct bpf_local_storage_map *)map;
+	return bpf_local_storage_lookup(inode_storage, smap, cacheit_lockit);
+}
+
+void bpf_inode_storage_free(struct inode *inode)
+{
+	struct bpf_local_storage_elem *selem;
+	struct bpf_local_storage *local_storage;
+	bool free_inode_storage = false;
+	struct bpf_storage_blob *bsb;
+	struct hlist_node *n;
+
+	bsb = bpf_inode(inode);
+	if (!bsb)
+		return;
+
+	rcu_read_lock();
+
+	local_storage = rcu_dereference(bsb->storage);
+	if (!local_storage) {
+		rcu_read_unlock();
+		return;
+	}
+
+	/* Neither the bpf_prog nor the bpf-map's syscall
+	 * could be modifying the local_storage->list now.
+	 * Thus, no elem can be added-to or deleted-from the
+	 * local_storage->list by the bpf_prog or by the bpf-map's syscall.
+	 *
+	 * It is racing with bpf_local_storage_map_free() alone
+	 * when unlinking elem from the local_storage->list and
+	 * the map's bucket->list.
+	 */
+	raw_spin_lock_bh(&local_storage->lock);
+	hlist_for_each_entry_safe(selem, n, &local_storage->list, snode) {
+		/* Always unlink from map before unlinking from
+		 * local_storage.
+		 */
+		bpf_selem_unlink_map(selem);
+		free_inode_storage = bpf_selem_unlink_storage_nolock(
+			local_storage, selem, false, false);
+	}
+	raw_spin_unlock_bh(&local_storage->lock);
+	rcu_read_unlock();
+
+	/* free_inoode_storage should always be true as long as
+	 * local_storage->list was non-empty.
+	 */
+	if (free_inode_storage)
+		kfree_rcu(local_storage, rcu);
+}
+
+static void *bpf_fd_inode_storage_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_local_storage_data *sdata;
+	struct file *f;
+	int fd;
+
+	fd = *(int *)key;
+	f = fget_raw(fd);
+	if (!f)
+		return ERR_PTR(-EBADF);
+
+	sdata = inode_storage_lookup(f->f_inode, map, true);
+	fput(f);
+	return sdata ? sdata->data : NULL;
+}
+
+static int bpf_fd_inode_storage_update_elem(struct bpf_map *map, void *key,
+					 void *value, u64 map_flags)
+{
+	struct bpf_local_storage_data *sdata;
+	struct file *f;
+	int fd;
+
+	fd = *(int *)key;
+	f = fget_raw(fd);
+	if (!f)
+		return -EBADF;
+	if (!inode_storage_ptr(f->f_inode)) {
+		fput(f);
+		return -EBADF;
+	}
+
+	sdata = bpf_local_storage_update(f->f_inode,
+					 (struct bpf_local_storage_map *)map,
+					 value, map_flags, GFP_ATOMIC);
+	fput(f);
+	return PTR_ERR_OR_ZERO(sdata);
+}
+
+static int inode_storage_delete(struct inode *inode, struct bpf_map *map)
+{
+	struct bpf_local_storage_data *sdata;
+
+	sdata = inode_storage_lookup(inode, map, false);
+	if (!sdata)
+		return -ENOENT;
+
+	bpf_selem_unlink(SELEM(sdata), true);
+
+	return 0;
+}
+
+static int bpf_fd_inode_storage_delete_elem(struct bpf_map *map, void *key)
+{
+	struct file *f;
+	int fd, err;
+
+	fd = *(int *)key;
+	f = fget_raw(fd);
+	if (!f)
+		return -EBADF;
+
+	err = inode_storage_delete(f->f_inode, map);
+	fput(f);
+	return err;
+}
+
+/* *gfp_flags* is a hidden argument provided by the verifier */
+BPF_CALL_5(bpf_inode_storage_get, struct bpf_map *, map, struct inode *, inode,
+	   void *, value, u64, flags, gfp_t, gfp_flags)
+{
+	struct bpf_local_storage_data *sdata;
+
+	WARN_ON_ONCE(!bpf_rcu_lock_held());
+	if (flags & ~(BPF_LOCAL_STORAGE_GET_F_CREATE))
+		return (unsigned long)NULL;
+
+	/* explicitly check that the inode_storage_ptr is not
+	 * NULL as inode_storage_lookup returns NULL in this case and
+	 * bpf_local_storage_update expects the owner to have a
+	 * valid storage pointer.
+	 */
+	if (!inode || !inode_storage_ptr(inode))
+		return (unsigned long)NULL;
+
+	sdata = inode_storage_lookup(inode, map, true);
+	if (sdata)
+		return (unsigned long)sdata->data;
+
+	/* This helper must only called from where the inode is guaranteed
+	 * to have a refcount and cannot be freed.
+	 */
+	if (flags & BPF_LOCAL_STORAGE_GET_F_CREATE) {
+		sdata = bpf_local_storage_update(
+			inode, (struct bpf_local_storage_map *)map, value,
+			BPF_NOEXIST, gfp_flags);
+		return IS_ERR(sdata) ? (unsigned long)NULL :
+					     (unsigned long)sdata->data;
+	}
+
+	return (unsigned long)NULL;
+}
+
+BPF_CALL_2(bpf_inode_storage_delete,
+	   struct bpf_map *, map, struct inode *, inode)
+{
+	WARN_ON_ONCE(!bpf_rcu_lock_held());
+	if (!inode)
+		return -EINVAL;
+
+	/* This helper must only called from where the inode is guaranteed
+	 * to have a refcount and cannot be freed.
+	 */
+	return inode_storage_delete(inode, map);
+}
+
+static int notsupp_get_next_key(struct bpf_map *map, void *key,
+				void *next_key)
+{
+	return -ENOTSUPP;
+}
+
+static struct bpf_map *inode_storage_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_local_storage_map *smap;
+
+	smap = bpf_local_storage_map_alloc(attr);
+	if (IS_ERR(smap))
+		return ERR_CAST(smap);
+
+	smap->cache_idx = bpf_local_storage_cache_idx_get(&inode_cache);
+	return &smap->map;
+}
+
+static void inode_storage_map_free(struct bpf_map *map)
+{
+	struct bpf_local_storage_map *smap;
+
+	smap = (struct bpf_local_storage_map *)map;
+	bpf_local_storage_cache_idx_free(&inode_cache, smap->cache_idx);
+	bpf_local_storage_map_free(smap, NULL);
+}
+
+BTF_ID_LIST_SINGLE(inode_storage_map_btf_ids, struct,
+		   bpf_local_storage_map)
+const struct bpf_map_ops inode_storage_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = bpf_local_storage_map_alloc_check,
+	.map_alloc = inode_storage_map_alloc,
+	.map_free = inode_storage_map_free,
+	.map_get_next_key = notsupp_get_next_key,
+	.map_lookup_elem = bpf_fd_inode_storage_lookup_elem,
+	.map_update_elem = bpf_fd_inode_storage_update_elem,
+	.map_delete_elem = bpf_fd_inode_storage_delete_elem,
+	.map_check_btf = bpf_local_storage_map_check_btf,
+	.map_btf_id = &inode_storage_map_btf_ids[0],
+	.map_owner_storage_ptr = inode_storage_ptr,
+};
+
+BTF_ID_LIST_SINGLE(bpf_inode_storage_btf_ids, struct, inode)
+
+const struct bpf_func_proto bpf_inode_storage_get_proto = {
+	.func		= bpf_inode_storage_get,
+	.gpl_only	= false,
+	.ret_type	= RET_PTR_TO_MAP_VALUE_OR_NULL,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_BTF_ID,
+	.arg2_btf_id	= &bpf_inode_storage_btf_ids[0],
+	.arg3_type	= ARG_PTR_TO_MAP_VALUE_OR_NULL,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+const struct bpf_func_proto bpf_inode_storage_delete_proto = {
+	.func		= bpf_inode_storage_delete,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_BTF_ID,
+	.arg2_btf_id	= &bpf_inode_storage_btf_ids[0],
+};
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
new file mode 100644
index 000000000..5dc307bde
--- /dev/null
+++ b/kernel/bpf/bpf_iter.c
@@ -0,0 +1,778 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2020 Facebook */
+
+#include <linux/fs.h>
+#include <linux/anon_inodes.h>
+#include <linux/filter.h>
+#include <linux/bpf.h>
+#include <linux/rcupdate_trace.h>
+
+struct bpf_iter_target_info {
+	struct list_head list;
+	const struct bpf_iter_reg *reg_info;
+	u32 btf_id;	/* cached value */
+};
+
+struct bpf_iter_link {
+	struct bpf_link link;
+	struct bpf_iter_aux_info aux;
+	struct bpf_iter_target_info *tinfo;
+};
+
+struct bpf_iter_priv_data {
+	struct bpf_iter_target_info *tinfo;
+	const struct bpf_iter_seq_info *seq_info;
+	struct bpf_prog *prog;
+	u64 session_id;
+	u64 seq_num;
+	bool done_stop;
+	u8 target_private[] __aligned(8);
+};
+
+static struct list_head targets = LIST_HEAD_INIT(targets);
+static DEFINE_MUTEX(targets_mutex);
+
+/* protect bpf_iter_link changes */
+static DEFINE_MUTEX(link_mutex);
+
+/* incremented on every opened seq_file */
+static atomic64_t session_id;
+
+static int prepare_seq_file(struct file *file, struct bpf_iter_link *link,
+			    const struct bpf_iter_seq_info *seq_info);
+
+static void bpf_iter_inc_seq_num(struct seq_file *seq)
+{
+	struct bpf_iter_priv_data *iter_priv;
+
+	iter_priv = container_of(seq->private, struct bpf_iter_priv_data,
+				 target_private);
+	iter_priv->seq_num++;
+}
+
+static void bpf_iter_dec_seq_num(struct seq_file *seq)
+{
+	struct bpf_iter_priv_data *iter_priv;
+
+	iter_priv = container_of(seq->private, struct bpf_iter_priv_data,
+				 target_private);
+	iter_priv->seq_num--;
+}
+
+static void bpf_iter_done_stop(struct seq_file *seq)
+{
+	struct bpf_iter_priv_data *iter_priv;
+
+	iter_priv = container_of(seq->private, struct bpf_iter_priv_data,
+				 target_private);
+	iter_priv->done_stop = true;
+}
+
+static inline bool bpf_iter_target_support_resched(const struct bpf_iter_target_info *tinfo)
+{
+	return tinfo->reg_info->feature & BPF_ITER_RESCHED;
+}
+
+static bool bpf_iter_support_resched(struct seq_file *seq)
+{
+	struct bpf_iter_priv_data *iter_priv;
+
+	iter_priv = container_of(seq->private, struct bpf_iter_priv_data,
+				 target_private);
+	return bpf_iter_target_support_resched(iter_priv->tinfo);
+}
+
+/* maximum visited objects before bailing out */
+#define MAX_ITER_OBJECTS	1000000
+
+/* bpf_seq_read, a customized and simpler version for bpf iterator.
+ * The following are differences from seq_read():
+ *  . fixed buffer size (PAGE_SIZE)
+ *  . assuming NULL ->llseek()
+ *  . stop() may call bpf program, handling potential overflow there
+ */
+static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,
+			    loff_t *ppos)
+{
+	struct seq_file *seq = file->private_data;
+	size_t n, offs, copied = 0;
+	int err = 0, num_objs = 0;
+	bool can_resched;
+	void *p;
+
+	mutex_lock(&seq->lock);
+
+	if (!seq->buf) {
+		seq->size = PAGE_SIZE << 3;
+		seq->buf = kvmalloc(seq->size, GFP_KERNEL);
+		if (!seq->buf) {
+			err = -ENOMEM;
+			goto done;
+		}
+	}
+
+	if (seq->count) {
+		n = min(seq->count, size);
+		err = copy_to_user(buf, seq->buf + seq->from, n);
+		if (err) {
+			err = -EFAULT;
+			goto done;
+		}
+		seq->count -= n;
+		seq->from += n;
+		copied = n;
+		goto done;
+	}
+
+	seq->from = 0;
+	p = seq->op->start(seq, &seq->index);
+	if (!p)
+		goto stop;
+	if (IS_ERR(p)) {
+		err = PTR_ERR(p);
+		seq->op->stop(seq, p);
+		seq->count = 0;
+		goto done;
+	}
+
+	err = seq->op->show(seq, p);
+	if (err > 0) {
+		/* object is skipped, decrease seq_num, so next
+		 * valid object can reuse the same seq_num.
+		 */
+		bpf_iter_dec_seq_num(seq);
+		seq->count = 0;
+	} else if (err < 0 || seq_has_overflowed(seq)) {
+		if (!err)
+			err = -E2BIG;
+		seq->op->stop(seq, p);
+		seq->count = 0;
+		goto done;
+	}
+
+	can_resched = bpf_iter_support_resched(seq);
+	while (1) {
+		loff_t pos = seq->index;
+
+		num_objs++;
+		offs = seq->count;
+		p = seq->op->next(seq, p, &seq->index);
+		if (pos == seq->index) {
+			pr_info_ratelimited("buggy seq_file .next function %ps "
+				"did not updated position index\n",
+				seq->op->next);
+			seq->index++;
+		}
+
+		if (IS_ERR_OR_NULL(p))
+			break;
+
+		/* got a valid next object, increase seq_num */
+		bpf_iter_inc_seq_num(seq);
+
+		if (seq->count >= size)
+			break;
+
+		if (num_objs >= MAX_ITER_OBJECTS) {
+			if (offs == 0) {
+				err = -EAGAIN;
+				seq->op->stop(seq, p);
+				goto done;
+			}
+			break;
+		}
+
+		err = seq->op->show(seq, p);
+		if (err > 0) {
+			bpf_iter_dec_seq_num(seq);
+			seq->count = offs;
+		} else if (err < 0 || seq_has_overflowed(seq)) {
+			seq->count = offs;
+			if (offs == 0) {
+				if (!err)
+					err = -E2BIG;
+				seq->op->stop(seq, p);
+				goto done;
+			}
+			break;
+		}
+
+		if (can_resched)
+			cond_resched();
+	}
+stop:
+	offs = seq->count;
+	if (IS_ERR(p)) {
+		seq->op->stop(seq, NULL);
+		err = PTR_ERR(p);
+		goto done;
+	}
+	/* bpf program called if !p */
+	seq->op->stop(seq, p);
+	if (!p) {
+		if (!seq_has_overflowed(seq)) {
+			bpf_iter_done_stop(seq);
+		} else {
+			seq->count = offs;
+			if (offs == 0) {
+				err = -E2BIG;
+				goto done;
+			}
+		}
+	}
+
+	n = min(seq->count, size);
+	err = copy_to_user(buf, seq->buf, n);
+	if (err) {
+		err = -EFAULT;
+		goto done;
+	}
+	copied = n;
+	seq->count -= n;
+	seq->from = n;
+done:
+	if (!copied)
+		copied = err;
+	else
+		*ppos += copied;
+	mutex_unlock(&seq->lock);
+	return copied;
+}
+
+static const struct bpf_iter_seq_info *
+__get_seq_info(struct bpf_iter_link *link)
+{
+	const struct bpf_iter_seq_info *seq_info;
+
+	if (link->aux.map) {
+		seq_info = link->aux.map->ops->iter_seq_info;
+		if (seq_info)
+			return seq_info;
+	}
+
+	return link->tinfo->reg_info->seq_info;
+}
+
+static int iter_open(struct inode *inode, struct file *file)
+{
+	struct bpf_iter_link *link = inode->i_private;
+
+	return prepare_seq_file(file, link, __get_seq_info(link));
+}
+
+static int iter_release(struct inode *inode, struct file *file)
+{
+	struct bpf_iter_priv_data *iter_priv;
+	struct seq_file *seq;
+
+	seq = file->private_data;
+	if (!seq)
+		return 0;
+
+	iter_priv = container_of(seq->private, struct bpf_iter_priv_data,
+				 target_private);
+
+	if (iter_priv->seq_info->fini_seq_private)
+		iter_priv->seq_info->fini_seq_private(seq->private);
+
+	bpf_prog_put(iter_priv->prog);
+	seq->private = iter_priv;
+
+	return seq_release_private(inode, file);
+}
+
+const struct file_operations bpf_iter_fops = {
+	.open		= iter_open,
+	.llseek		= no_llseek,
+	.read		= bpf_seq_read,
+	.release	= iter_release,
+};
+
+/* The argument reg_info will be cached in bpf_iter_target_info.
+ * The common practice is to declare target reg_info as
+ * a const static variable and passed as an argument to
+ * bpf_iter_reg_target().
+ */
+int bpf_iter_reg_target(const struct bpf_iter_reg *reg_info)
+{
+	struct bpf_iter_target_info *tinfo;
+
+	tinfo = kzalloc(sizeof(*tinfo), GFP_KERNEL);
+	if (!tinfo)
+		return -ENOMEM;
+
+	tinfo->reg_info = reg_info;
+	INIT_LIST_HEAD(&tinfo->list);
+
+	mutex_lock(&targets_mutex);
+	list_add(&tinfo->list, &targets);
+	mutex_unlock(&targets_mutex);
+
+	return 0;
+}
+
+void bpf_iter_unreg_target(const struct bpf_iter_reg *reg_info)
+{
+	struct bpf_iter_target_info *tinfo;
+	bool found = false;
+
+	mutex_lock(&targets_mutex);
+	list_for_each_entry(tinfo, &targets, list) {
+		if (reg_info == tinfo->reg_info) {
+			list_del(&tinfo->list);
+			kfree(tinfo);
+			found = true;
+			break;
+		}
+	}
+	mutex_unlock(&targets_mutex);
+
+	WARN_ON(found == false);
+}
+
+static void cache_btf_id(struct bpf_iter_target_info *tinfo,
+			 struct bpf_prog *prog)
+{
+	tinfo->btf_id = prog->aux->attach_btf_id;
+}
+
+bool bpf_iter_prog_supported(struct bpf_prog *prog)
+{
+	const char *attach_fname = prog->aux->attach_func_name;
+	struct bpf_iter_target_info *tinfo = NULL, *iter;
+	u32 prog_btf_id = prog->aux->attach_btf_id;
+	const char *prefix = BPF_ITER_FUNC_PREFIX;
+	int prefix_len = strlen(prefix);
+
+	if (strncmp(attach_fname, prefix, prefix_len))
+		return false;
+
+	mutex_lock(&targets_mutex);
+	list_for_each_entry(iter, &targets, list) {
+		if (iter->btf_id && iter->btf_id == prog_btf_id) {
+			tinfo = iter;
+			break;
+		}
+		if (!strcmp(attach_fname + prefix_len, iter->reg_info->target)) {
+			cache_btf_id(iter, prog);
+			tinfo = iter;
+			break;
+		}
+	}
+	mutex_unlock(&targets_mutex);
+
+	if (tinfo) {
+		prog->aux->ctx_arg_info_size = tinfo->reg_info->ctx_arg_info_size;
+		prog->aux->ctx_arg_info = tinfo->reg_info->ctx_arg_info;
+	}
+
+	return tinfo != NULL;
+}
+
+const struct bpf_func_proto *
+bpf_iter_get_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	const struct bpf_iter_target_info *tinfo;
+	const struct bpf_func_proto *fn = NULL;
+
+	mutex_lock(&targets_mutex);
+	list_for_each_entry(tinfo, &targets, list) {
+		if (tinfo->btf_id == prog->aux->attach_btf_id) {
+			const struct bpf_iter_reg *reg_info;
+
+			reg_info = tinfo->reg_info;
+			if (reg_info->get_func_proto)
+				fn = reg_info->get_func_proto(func_id, prog);
+			break;
+		}
+	}
+	mutex_unlock(&targets_mutex);
+
+	return fn;
+}
+
+static void bpf_iter_link_release(struct bpf_link *link)
+{
+	struct bpf_iter_link *iter_link =
+		container_of(link, struct bpf_iter_link, link);
+
+	if (iter_link->tinfo->reg_info->detach_target)
+		iter_link->tinfo->reg_info->detach_target(&iter_link->aux);
+}
+
+static void bpf_iter_link_dealloc(struct bpf_link *link)
+{
+	struct bpf_iter_link *iter_link =
+		container_of(link, struct bpf_iter_link, link);
+
+	kfree(iter_link);
+}
+
+static int bpf_iter_link_replace(struct bpf_link *link,
+				 struct bpf_prog *new_prog,
+				 struct bpf_prog *old_prog)
+{
+	int ret = 0;
+
+	mutex_lock(&link_mutex);
+	if (old_prog && link->prog != old_prog) {
+		ret = -EPERM;
+		goto out_unlock;
+	}
+
+	if (link->prog->type != new_prog->type ||
+	    link->prog->expected_attach_type != new_prog->expected_attach_type ||
+	    link->prog->aux->attach_btf_id != new_prog->aux->attach_btf_id) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	old_prog = xchg(&link->prog, new_prog);
+	bpf_prog_put(old_prog);
+
+out_unlock:
+	mutex_unlock(&link_mutex);
+	return ret;
+}
+
+static void bpf_iter_link_show_fdinfo(const struct bpf_link *link,
+				      struct seq_file *seq)
+{
+	struct bpf_iter_link *iter_link =
+		container_of(link, struct bpf_iter_link, link);
+	bpf_iter_show_fdinfo_t show_fdinfo;
+
+	seq_printf(seq,
+		   "target_name:\t%s\n",
+		   iter_link->tinfo->reg_info->target);
+
+	show_fdinfo = iter_link->tinfo->reg_info->show_fdinfo;
+	if (show_fdinfo)
+		show_fdinfo(&iter_link->aux, seq);
+}
+
+static int bpf_iter_link_fill_link_info(const struct bpf_link *link,
+					struct bpf_link_info *info)
+{
+	struct bpf_iter_link *iter_link =
+		container_of(link, struct bpf_iter_link, link);
+	char __user *ubuf = u64_to_user_ptr(info->iter.target_name);
+	bpf_iter_fill_link_info_t fill_link_info;
+	u32 ulen = info->iter.target_name_len;
+	const char *target_name;
+	u32 target_len;
+
+	if (!ulen ^ !ubuf)
+		return -EINVAL;
+
+	target_name = iter_link->tinfo->reg_info->target;
+	target_len =  strlen(target_name);
+	info->iter.target_name_len = target_len + 1;
+
+	if (ubuf) {
+		if (ulen >= target_len + 1) {
+			if (copy_to_user(ubuf, target_name, target_len + 1))
+				return -EFAULT;
+		} else {
+			char zero = '\0';
+
+			if (copy_to_user(ubuf, target_name, ulen - 1))
+				return -EFAULT;
+			if (put_user(zero, ubuf + ulen - 1))
+				return -EFAULT;
+			return -ENOSPC;
+		}
+	}
+
+	fill_link_info = iter_link->tinfo->reg_info->fill_link_info;
+	if (fill_link_info)
+		return fill_link_info(&iter_link->aux, info);
+
+	return 0;
+}
+
+static const struct bpf_link_ops bpf_iter_link_lops = {
+	.release = bpf_iter_link_release,
+	.dealloc = bpf_iter_link_dealloc,
+	.update_prog = bpf_iter_link_replace,
+	.show_fdinfo = bpf_iter_link_show_fdinfo,
+	.fill_link_info = bpf_iter_link_fill_link_info,
+};
+
+bool bpf_link_is_iter(struct bpf_link *link)
+{
+	return link->ops == &bpf_iter_link_lops;
+}
+
+int bpf_iter_link_attach(const union bpf_attr *attr, bpfptr_t uattr,
+			 struct bpf_prog *prog)
+{
+	struct bpf_iter_target_info *tinfo = NULL, *iter;
+	struct bpf_link_primer link_primer;
+	union bpf_iter_link_info linfo;
+	struct bpf_iter_link *link;
+	u32 prog_btf_id, linfo_len;
+	bpfptr_t ulinfo;
+	int err;
+
+	if (attr->link_create.target_fd || attr->link_create.flags)
+		return -EINVAL;
+
+	memset(&linfo, 0, sizeof(union bpf_iter_link_info));
+
+	ulinfo = make_bpfptr(attr->link_create.iter_info, uattr.is_kernel);
+	linfo_len = attr->link_create.iter_info_len;
+	if (bpfptr_is_null(ulinfo) ^ !linfo_len)
+		return -EINVAL;
+
+	if (!bpfptr_is_null(ulinfo)) {
+		err = bpf_check_uarg_tail_zero(ulinfo, sizeof(linfo),
+					       linfo_len);
+		if (err)
+			return err;
+		linfo_len = min_t(u32, linfo_len, sizeof(linfo));
+		if (copy_from_bpfptr(&linfo, ulinfo, linfo_len))
+			return -EFAULT;
+	}
+
+	prog_btf_id = prog->aux->attach_btf_id;
+	mutex_lock(&targets_mutex);
+	list_for_each_entry(iter, &targets, list) {
+		if (iter->btf_id == prog_btf_id) {
+			tinfo = iter;
+			break;
+		}
+	}
+	mutex_unlock(&targets_mutex);
+	if (!tinfo)
+		return -ENOENT;
+
+	/* Only allow sleepable program for resched-able iterator */
+	if (prog->aux->sleepable && !bpf_iter_target_support_resched(tinfo))
+		return -EINVAL;
+
+	link = kzalloc(sizeof(*link), GFP_USER | __GFP_NOWARN);
+	if (!link)
+		return -ENOMEM;
+
+	bpf_link_init(&link->link, BPF_LINK_TYPE_ITER, &bpf_iter_link_lops, prog);
+	link->tinfo = tinfo;
+
+	err = bpf_link_prime(&link->link, &link_primer);
+	if (err) {
+		kfree(link);
+		return err;
+	}
+
+	if (tinfo->reg_info->attach_target) {
+		err = tinfo->reg_info->attach_target(prog, &linfo, &link->aux);
+		if (err) {
+			bpf_link_cleanup(&link_primer);
+			return err;
+		}
+	}
+
+	return bpf_link_settle(&link_primer);
+}
+
+static void init_seq_meta(struct bpf_iter_priv_data *priv_data,
+			  struct bpf_iter_target_info *tinfo,
+			  const struct bpf_iter_seq_info *seq_info,
+			  struct bpf_prog *prog)
+{
+	priv_data->tinfo = tinfo;
+	priv_data->seq_info = seq_info;
+	priv_data->prog = prog;
+	priv_data->session_id = atomic64_inc_return(&session_id);
+	priv_data->seq_num = 0;
+	priv_data->done_stop = false;
+}
+
+static int prepare_seq_file(struct file *file, struct bpf_iter_link *link,
+			    const struct bpf_iter_seq_info *seq_info)
+{
+	struct bpf_iter_priv_data *priv_data;
+	struct bpf_iter_target_info *tinfo;
+	struct bpf_prog *prog;
+	u32 total_priv_dsize;
+	struct seq_file *seq;
+	int err = 0;
+
+	mutex_lock(&link_mutex);
+	prog = link->link.prog;
+	bpf_prog_inc(prog);
+	mutex_unlock(&link_mutex);
+
+	tinfo = link->tinfo;
+	total_priv_dsize = offsetof(struct bpf_iter_priv_data, target_private) +
+			   seq_info->seq_priv_size;
+	priv_data = __seq_open_private(file, seq_info->seq_ops,
+				       total_priv_dsize);
+	if (!priv_data) {
+		err = -ENOMEM;
+		goto release_prog;
+	}
+
+	if (seq_info->init_seq_private) {
+		err = seq_info->init_seq_private(priv_data->target_private, &link->aux);
+		if (err)
+			goto release_seq_file;
+	}
+
+	init_seq_meta(priv_data, tinfo, seq_info, prog);
+	seq = file->private_data;
+	seq->private = priv_data->target_private;
+
+	return 0;
+
+release_seq_file:
+	seq_release_private(file->f_inode, file);
+	file->private_data = NULL;
+release_prog:
+	bpf_prog_put(prog);
+	return err;
+}
+
+int bpf_iter_new_fd(struct bpf_link *link)
+{
+	struct bpf_iter_link *iter_link;
+	struct file *file;
+	unsigned int flags;
+	int err, fd;
+
+	if (link->ops != &bpf_iter_link_lops)
+		return -EINVAL;
+
+	flags = O_RDONLY | O_CLOEXEC;
+	fd = get_unused_fd_flags(flags);
+	if (fd < 0)
+		return fd;
+
+	file = anon_inode_getfile("bpf_iter", &bpf_iter_fops, NULL, flags);
+	if (IS_ERR(file)) {
+		err = PTR_ERR(file);
+		goto free_fd;
+	}
+
+	iter_link = container_of(link, struct bpf_iter_link, link);
+	err = prepare_seq_file(file, iter_link, __get_seq_info(iter_link));
+	if (err)
+		goto free_file;
+
+	fd_install(fd, file);
+	return fd;
+
+free_file:
+	fput(file);
+free_fd:
+	put_unused_fd(fd);
+	return err;
+}
+
+struct bpf_prog *bpf_iter_get_info(struct bpf_iter_meta *meta, bool in_stop)
+{
+	struct bpf_iter_priv_data *iter_priv;
+	struct seq_file *seq;
+	void *seq_priv;
+
+	seq = meta->seq;
+	if (seq->file->f_op != &bpf_iter_fops)
+		return NULL;
+
+	seq_priv = seq->private;
+	iter_priv = container_of(seq_priv, struct bpf_iter_priv_data,
+				 target_private);
+
+	if (in_stop && iter_priv->done_stop)
+		return NULL;
+
+	meta->session_id = iter_priv->session_id;
+	meta->seq_num = iter_priv->seq_num;
+
+	return iter_priv->prog;
+}
+
+int bpf_iter_run_prog(struct bpf_prog *prog, void *ctx)
+{
+	struct bpf_run_ctx run_ctx, *old_run_ctx;
+	int ret;
+
+	if (prog->aux->sleepable) {
+		rcu_read_lock_trace();
+		migrate_disable();
+		might_fault();
+		old_run_ctx = bpf_set_run_ctx(&run_ctx);
+		ret = bpf_prog_run(prog, ctx);
+		bpf_reset_run_ctx(old_run_ctx);
+		migrate_enable();
+		rcu_read_unlock_trace();
+	} else {
+		rcu_read_lock();
+		migrate_disable();
+		old_run_ctx = bpf_set_run_ctx(&run_ctx);
+		ret = bpf_prog_run(prog, ctx);
+		bpf_reset_run_ctx(old_run_ctx);
+		migrate_enable();
+		rcu_read_unlock();
+	}
+
+	/* bpf program can only return 0 or 1:
+	 *  0 : okay
+	 *  1 : retry the same object
+	 * The bpf_iter_run_prog() return value
+	 * will be seq_ops->show() return value.
+	 */
+	return ret == 0 ? 0 : -EAGAIN;
+}
+
+BPF_CALL_4(bpf_for_each_map_elem, struct bpf_map *, map, void *, callback_fn,
+	   void *, callback_ctx, u64, flags)
+{
+	return map->ops->map_for_each_callback(map, callback_fn, callback_ctx, flags);
+}
+
+const struct bpf_func_proto bpf_for_each_map_elem_proto = {
+	.func		= bpf_for_each_map_elem,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_FUNC,
+	.arg3_type	= ARG_PTR_TO_STACK_OR_NULL,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_4(bpf_loop, u32, nr_loops, void *, callback_fn, void *, callback_ctx,
+	   u64, flags)
+{
+	bpf_callback_t callback = (bpf_callback_t)callback_fn;
+	u64 ret;
+	u32 i;
+
+	/* Note: these safety checks are also verified when bpf_loop
+	 * is inlined, be careful to modify this code in sync. See
+	 * function verifier.c:inline_bpf_loop.
+	 */
+	if (flags)
+		return -EINVAL;
+	if (nr_loops > BPF_MAX_LOOPS)
+		return -E2BIG;
+
+	for (i = 0; i < nr_loops; i++) {
+		ret = callback((u64)i, (u64)(long)callback_ctx, 0, 0, 0);
+		/* return value: 0 - continue, 1 - stop and return */
+		if (ret)
+			return i + 1;
+	}
+
+	return i;
+}
+
+const struct bpf_func_proto bpf_loop_proto = {
+	.func		= bpf_loop,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_ANYTHING,
+	.arg2_type	= ARG_PTR_TO_FUNC,
+	.arg3_type	= ARG_PTR_TO_STACK_OR_NULL,
+	.arg4_type	= ARG_ANYTHING,
+};
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
new file mode 100644
index 000000000..d9d88a2cd
--- /dev/null
+++ b/kernel/bpf/bpf_local_storage.c
@@ -0,0 +1,666 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2019 Facebook  */
+#include <linux/rculist.h>
+#include <linux/list.h>
+#include <linux/hash.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/bpf.h>
+#include <linux/btf_ids.h>
+#include <linux/bpf_local_storage.h>
+#include <net/sock.h>
+#include <uapi/linux/sock_diag.h>
+#include <uapi/linux/btf.h>
+#include <linux/rcupdate.h>
+#include <linux/rcupdate_trace.h>
+#include <linux/rcupdate_wait.h>
+
+#define BPF_LOCAL_STORAGE_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_CLONE)
+
+static struct bpf_local_storage_map_bucket *
+select_bucket(struct bpf_local_storage_map *smap,
+	      struct bpf_local_storage_elem *selem)
+{
+	return &smap->buckets[hash_ptr(selem, smap->bucket_log)];
+}
+
+static int mem_charge(struct bpf_local_storage_map *smap, void *owner, u32 size)
+{
+	struct bpf_map *map = &smap->map;
+
+	if (!map->ops->map_local_storage_charge)
+		return 0;
+
+	return map->ops->map_local_storage_charge(smap, owner, size);
+}
+
+static void mem_uncharge(struct bpf_local_storage_map *smap, void *owner,
+			 u32 size)
+{
+	struct bpf_map *map = &smap->map;
+
+	if (map->ops->map_local_storage_uncharge)
+		map->ops->map_local_storage_uncharge(smap, owner, size);
+}
+
+static struct bpf_local_storage __rcu **
+owner_storage(struct bpf_local_storage_map *smap, void *owner)
+{
+	struct bpf_map *map = &smap->map;
+
+	return map->ops->map_owner_storage_ptr(owner);
+}
+
+static bool selem_linked_to_storage_lockless(const struct bpf_local_storage_elem *selem)
+{
+	return !hlist_unhashed_lockless(&selem->snode);
+}
+
+static bool selem_linked_to_storage(const struct bpf_local_storage_elem *selem)
+{
+	return !hlist_unhashed(&selem->snode);
+}
+
+static bool selem_linked_to_map_lockless(const struct bpf_local_storage_elem *selem)
+{
+	return !hlist_unhashed_lockless(&selem->map_node);
+}
+
+static bool selem_linked_to_map(const struct bpf_local_storage_elem *selem)
+{
+	return !hlist_unhashed(&selem->map_node);
+}
+
+struct bpf_local_storage_elem *
+bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner,
+		void *value, bool charge_mem, gfp_t gfp_flags)
+{
+	struct bpf_local_storage_elem *selem;
+
+	if (charge_mem && mem_charge(smap, owner, smap->elem_size))
+		return NULL;
+
+	selem = bpf_map_kzalloc(&smap->map, smap->elem_size,
+				gfp_flags | __GFP_NOWARN);
+	if (selem) {
+		if (value)
+			copy_map_value(&smap->map, SDATA(selem)->data, value);
+		return selem;
+	}
+
+	if (charge_mem)
+		mem_uncharge(smap, owner, smap->elem_size);
+
+	return NULL;
+}
+
+void bpf_local_storage_free_rcu(struct rcu_head *rcu)
+{
+	struct bpf_local_storage *local_storage;
+
+	local_storage = container_of(rcu, struct bpf_local_storage, rcu);
+	kfree_rcu(local_storage, rcu);
+}
+
+static void bpf_selem_free_rcu(struct rcu_head *rcu)
+{
+	struct bpf_local_storage_elem *selem;
+
+	selem = container_of(rcu, struct bpf_local_storage_elem, rcu);
+	kfree_rcu(selem, rcu);
+}
+
+/* local_storage->lock must be held and selem->local_storage == local_storage.
+ * The caller must ensure selem->smap is still valid to be
+ * dereferenced for its smap->elem_size and smap->cache_idx.
+ */
+bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage,
+				     struct bpf_local_storage_elem *selem,
+				     bool uncharge_mem, bool use_trace_rcu)
+{
+	struct bpf_local_storage_map *smap;
+	bool free_local_storage;
+	void *owner;
+
+	smap = rcu_dereference_check(SDATA(selem)->smap, bpf_rcu_lock_held());
+	owner = local_storage->owner;
+
+	/* All uncharging on the owner must be done first.
+	 * The owner may be freed once the last selem is unlinked
+	 * from local_storage.
+	 */
+	if (uncharge_mem)
+		mem_uncharge(smap, owner, smap->elem_size);
+
+	free_local_storage = hlist_is_singular_node(&selem->snode,
+						    &local_storage->list);
+	if (free_local_storage) {
+		mem_uncharge(smap, owner, sizeof(struct bpf_local_storage));
+		local_storage->owner = NULL;
+
+		/* After this RCU_INIT, owner may be freed and cannot be used */
+		RCU_INIT_POINTER(*owner_storage(smap, owner), NULL);
+
+		/* local_storage is not freed now.  local_storage->lock is
+		 * still held and raw_spin_unlock_bh(&local_storage->lock)
+		 * will be done by the caller.
+		 *
+		 * Although the unlock will be done under
+		 * rcu_read_lock(),  it is more intuitive to
+		 * read if the freeing of the storage is done
+		 * after the raw_spin_unlock_bh(&local_storage->lock).
+		 *
+		 * Hence, a "bool free_local_storage" is returned
+		 * to the caller which then calls then frees the storage after
+		 * all the RCU grace periods have expired.
+		 */
+	}
+	hlist_del_init_rcu(&selem->snode);
+	if (rcu_access_pointer(local_storage->cache[smap->cache_idx]) ==
+	    SDATA(selem))
+		RCU_INIT_POINTER(local_storage->cache[smap->cache_idx], NULL);
+
+	if (use_trace_rcu)
+		call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_rcu);
+	else
+		kfree_rcu(selem, rcu);
+
+	return free_local_storage;
+}
+
+static void __bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem,
+				       bool use_trace_rcu)
+{
+	struct bpf_local_storage *local_storage;
+	bool free_local_storage = false;
+	unsigned long flags;
+
+	if (unlikely(!selem_linked_to_storage_lockless(selem)))
+		/* selem has already been unlinked from sk */
+		return;
+
+	local_storage = rcu_dereference_check(selem->local_storage,
+					      bpf_rcu_lock_held());
+	raw_spin_lock_irqsave(&local_storage->lock, flags);
+	if (likely(selem_linked_to_storage(selem)))
+		free_local_storage = bpf_selem_unlink_storage_nolock(
+			local_storage, selem, true, use_trace_rcu);
+	raw_spin_unlock_irqrestore(&local_storage->lock, flags);
+
+	if (free_local_storage) {
+		if (use_trace_rcu)
+			call_rcu_tasks_trace(&local_storage->rcu,
+				     bpf_local_storage_free_rcu);
+		else
+			kfree_rcu(local_storage, rcu);
+	}
+}
+
+void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage,
+				   struct bpf_local_storage_elem *selem)
+{
+	RCU_INIT_POINTER(selem->local_storage, local_storage);
+	hlist_add_head_rcu(&selem->snode, &local_storage->list);
+}
+
+void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem)
+{
+	struct bpf_local_storage_map *smap;
+	struct bpf_local_storage_map_bucket *b;
+	unsigned long flags;
+
+	if (unlikely(!selem_linked_to_map_lockless(selem)))
+		/* selem has already be unlinked from smap */
+		return;
+
+	smap = rcu_dereference_check(SDATA(selem)->smap, bpf_rcu_lock_held());
+	b = select_bucket(smap, selem);
+	raw_spin_lock_irqsave(&b->lock, flags);
+	if (likely(selem_linked_to_map(selem)))
+		hlist_del_init_rcu(&selem->map_node);
+	raw_spin_unlock_irqrestore(&b->lock, flags);
+}
+
+void bpf_selem_link_map(struct bpf_local_storage_map *smap,
+			struct bpf_local_storage_elem *selem)
+{
+	struct bpf_local_storage_map_bucket *b = select_bucket(smap, selem);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&b->lock, flags);
+	RCU_INIT_POINTER(SDATA(selem)->smap, smap);
+	hlist_add_head_rcu(&selem->map_node, &b->list);
+	raw_spin_unlock_irqrestore(&b->lock, flags);
+}
+
+void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool use_trace_rcu)
+{
+	/* Always unlink from map before unlinking from local_storage
+	 * because selem will be freed after successfully unlinked from
+	 * the local_storage.
+	 */
+	bpf_selem_unlink_map(selem);
+	__bpf_selem_unlink_storage(selem, use_trace_rcu);
+}
+
+struct bpf_local_storage_data *
+bpf_local_storage_lookup(struct bpf_local_storage *local_storage,
+			 struct bpf_local_storage_map *smap,
+			 bool cacheit_lockit)
+{
+	struct bpf_local_storage_data *sdata;
+	struct bpf_local_storage_elem *selem;
+
+	/* Fast path (cache hit) */
+	sdata = rcu_dereference_check(local_storage->cache[smap->cache_idx],
+				      bpf_rcu_lock_held());
+	if (sdata && rcu_access_pointer(sdata->smap) == smap)
+		return sdata;
+
+	/* Slow path (cache miss) */
+	hlist_for_each_entry_rcu(selem, &local_storage->list, snode,
+				  rcu_read_lock_trace_held())
+		if (rcu_access_pointer(SDATA(selem)->smap) == smap)
+			break;
+
+	if (!selem)
+		return NULL;
+
+	sdata = SDATA(selem);
+	if (cacheit_lockit) {
+		unsigned long flags;
+
+		/* spinlock is needed to avoid racing with the
+		 * parallel delete.  Otherwise, publishing an already
+		 * deleted sdata to the cache will become a use-after-free
+		 * problem in the next bpf_local_storage_lookup().
+		 */
+		raw_spin_lock_irqsave(&local_storage->lock, flags);
+		if (selem_linked_to_storage(selem))
+			rcu_assign_pointer(local_storage->cache[smap->cache_idx],
+					   sdata);
+		raw_spin_unlock_irqrestore(&local_storage->lock, flags);
+	}
+
+	return sdata;
+}
+
+static int check_flags(const struct bpf_local_storage_data *old_sdata,
+		       u64 map_flags)
+{
+	if (old_sdata && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
+		/* elem already exists */
+		return -EEXIST;
+
+	if (!old_sdata && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
+		/* elem doesn't exist, cannot update it */
+		return -ENOENT;
+
+	return 0;
+}
+
+int bpf_local_storage_alloc(void *owner,
+			    struct bpf_local_storage_map *smap,
+			    struct bpf_local_storage_elem *first_selem,
+			    gfp_t gfp_flags)
+{
+	struct bpf_local_storage *prev_storage, *storage;
+	struct bpf_local_storage **owner_storage_ptr;
+	int err;
+
+	err = mem_charge(smap, owner, sizeof(*storage));
+	if (err)
+		return err;
+
+	storage = bpf_map_kzalloc(&smap->map, sizeof(*storage),
+				  gfp_flags | __GFP_NOWARN);
+	if (!storage) {
+		err = -ENOMEM;
+		goto uncharge;
+	}
+
+	INIT_HLIST_HEAD(&storage->list);
+	raw_spin_lock_init(&storage->lock);
+	storage->owner = owner;
+
+	bpf_selem_link_storage_nolock(storage, first_selem);
+	bpf_selem_link_map(smap, first_selem);
+
+	owner_storage_ptr =
+		(struct bpf_local_storage **)owner_storage(smap, owner);
+	/* Publish storage to the owner.
+	 * Instead of using any lock of the kernel object (i.e. owner),
+	 * cmpxchg will work with any kernel object regardless what
+	 * the running context is, bh, irq...etc.
+	 *
+	 * From now on, the owner->storage pointer (e.g. sk->sk_bpf_storage)
+	 * is protected by the storage->lock.  Hence, when freeing
+	 * the owner->storage, the storage->lock must be held before
+	 * setting owner->storage ptr to NULL.
+	 */
+	prev_storage = cmpxchg(owner_storage_ptr, NULL, storage);
+	if (unlikely(prev_storage)) {
+		bpf_selem_unlink_map(first_selem);
+		err = -EAGAIN;
+		goto uncharge;
+
+		/* Note that even first_selem was linked to smap's
+		 * bucket->list, first_selem can be freed immediately
+		 * (instead of kfree_rcu) because
+		 * bpf_local_storage_map_free() does a
+		 * synchronize_rcu_mult (waiting for both sleepable and
+		 * normal programs) before walking the bucket->list.
+		 * Hence, no one is accessing selem from the
+		 * bucket->list under rcu_read_lock().
+		 */
+	}
+
+	return 0;
+
+uncharge:
+	kfree(storage);
+	mem_uncharge(smap, owner, sizeof(*storage));
+	return err;
+}
+
+/* sk cannot be going away because it is linking new elem
+ * to sk->sk_bpf_storage. (i.e. sk->sk_refcnt cannot be 0).
+ * Otherwise, it will become a leak (and other memory issues
+ * during map destruction).
+ */
+struct bpf_local_storage_data *
+bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap,
+			 void *value, u64 map_flags, gfp_t gfp_flags)
+{
+	struct bpf_local_storage_data *old_sdata = NULL;
+	struct bpf_local_storage_elem *selem = NULL;
+	struct bpf_local_storage *local_storage;
+	unsigned long flags;
+	int err;
+
+	/* BPF_EXIST and BPF_NOEXIST cannot be both set */
+	if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST) ||
+	    /* BPF_F_LOCK can only be used in a value with spin_lock */
+	    unlikely((map_flags & BPF_F_LOCK) &&
+		     !map_value_has_spin_lock(&smap->map)))
+		return ERR_PTR(-EINVAL);
+
+	if (gfp_flags == GFP_KERNEL && (map_flags & ~BPF_F_LOCK) != BPF_NOEXIST)
+		return ERR_PTR(-EINVAL);
+
+	local_storage = rcu_dereference_check(*owner_storage(smap, owner),
+					      bpf_rcu_lock_held());
+	if (!local_storage || hlist_empty(&local_storage->list)) {
+		/* Very first elem for the owner */
+		err = check_flags(NULL, map_flags);
+		if (err)
+			return ERR_PTR(err);
+
+		selem = bpf_selem_alloc(smap, owner, value, true, gfp_flags);
+		if (!selem)
+			return ERR_PTR(-ENOMEM);
+
+		err = bpf_local_storage_alloc(owner, smap, selem, gfp_flags);
+		if (err) {
+			kfree(selem);
+			mem_uncharge(smap, owner, smap->elem_size);
+			return ERR_PTR(err);
+		}
+
+		return SDATA(selem);
+	}
+
+	if ((map_flags & BPF_F_LOCK) && !(map_flags & BPF_NOEXIST)) {
+		/* Hoping to find an old_sdata to do inline update
+		 * such that it can avoid taking the local_storage->lock
+		 * and changing the lists.
+		 */
+		old_sdata =
+			bpf_local_storage_lookup(local_storage, smap, false);
+		err = check_flags(old_sdata, map_flags);
+		if (err)
+			return ERR_PTR(err);
+		if (old_sdata && selem_linked_to_storage_lockless(SELEM(old_sdata))) {
+			copy_map_value_locked(&smap->map, old_sdata->data,
+					      value, false);
+			return old_sdata;
+		}
+	}
+
+	if (gfp_flags == GFP_KERNEL) {
+		selem = bpf_selem_alloc(smap, owner, value, true, gfp_flags);
+		if (!selem)
+			return ERR_PTR(-ENOMEM);
+	}
+
+	raw_spin_lock_irqsave(&local_storage->lock, flags);
+
+	/* Recheck local_storage->list under local_storage->lock */
+	if (unlikely(hlist_empty(&local_storage->list))) {
+		/* A parallel del is happening and local_storage is going
+		 * away.  It has just been checked before, so very
+		 * unlikely.  Return instead of retry to keep things
+		 * simple.
+		 */
+		err = -EAGAIN;
+		goto unlock_err;
+	}
+
+	old_sdata = bpf_local_storage_lookup(local_storage, smap, false);
+	err = check_flags(old_sdata, map_flags);
+	if (err)
+		goto unlock_err;
+
+	if (old_sdata && (map_flags & BPF_F_LOCK)) {
+		copy_map_value_locked(&smap->map, old_sdata->data, value,
+				      false);
+		selem = SELEM(old_sdata);
+		goto unlock;
+	}
+
+	if (gfp_flags != GFP_KERNEL) {
+		/* local_storage->lock is held.  Hence, we are sure
+		 * we can unlink and uncharge the old_sdata successfully
+		 * later.  Hence, instead of charging the new selem now
+		 * and then uncharge the old selem later (which may cause
+		 * a potential but unnecessary charge failure),  avoid taking
+		 * a charge at all here (the "!old_sdata" check) and the
+		 * old_sdata will not be uncharged later during
+		 * bpf_selem_unlink_storage_nolock().
+		 */
+		selem = bpf_selem_alloc(smap, owner, value, !old_sdata, gfp_flags);
+		if (!selem) {
+			err = -ENOMEM;
+			goto unlock_err;
+		}
+	}
+
+	/* First, link the new selem to the map */
+	bpf_selem_link_map(smap, selem);
+
+	/* Second, link (and publish) the new selem to local_storage */
+	bpf_selem_link_storage_nolock(local_storage, selem);
+
+	/* Third, remove old selem, SELEM(old_sdata) */
+	if (old_sdata) {
+		bpf_selem_unlink_map(SELEM(old_sdata));
+		bpf_selem_unlink_storage_nolock(local_storage, SELEM(old_sdata),
+						false, true);
+	}
+
+unlock:
+	raw_spin_unlock_irqrestore(&local_storage->lock, flags);
+	return SDATA(selem);
+
+unlock_err:
+	raw_spin_unlock_irqrestore(&local_storage->lock, flags);
+	if (selem) {
+		mem_uncharge(smap, owner, smap->elem_size);
+		kfree(selem);
+	}
+	return ERR_PTR(err);
+}
+
+u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache)
+{
+	u64 min_usage = U64_MAX;
+	u16 i, res = 0;
+
+	spin_lock(&cache->idx_lock);
+
+	for (i = 0; i < BPF_LOCAL_STORAGE_CACHE_SIZE; i++) {
+		if (cache->idx_usage_counts[i] < min_usage) {
+			min_usage = cache->idx_usage_counts[i];
+			res = i;
+
+			/* Found a free cache_idx */
+			if (!min_usage)
+				break;
+		}
+	}
+	cache->idx_usage_counts[res]++;
+
+	spin_unlock(&cache->idx_lock);
+
+	return res;
+}
+
+void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache,
+				      u16 idx)
+{
+	spin_lock(&cache->idx_lock);
+	cache->idx_usage_counts[idx]--;
+	spin_unlock(&cache->idx_lock);
+}
+
+void bpf_local_storage_map_free(struct bpf_local_storage_map *smap,
+				int __percpu *busy_counter)
+{
+	struct bpf_local_storage_elem *selem;
+	struct bpf_local_storage_map_bucket *b;
+	unsigned int i;
+
+	/* Note that this map might be concurrently cloned from
+	 * bpf_sk_storage_clone. Wait for any existing bpf_sk_storage_clone
+	 * RCU read section to finish before proceeding. New RCU
+	 * read sections should be prevented via bpf_map_inc_not_zero.
+	 */
+	synchronize_rcu();
+
+	/* bpf prog and the userspace can no longer access this map
+	 * now.  No new selem (of this map) can be added
+	 * to the owner->storage or to the map bucket's list.
+	 *
+	 * The elem of this map can be cleaned up here
+	 * or when the storage is freed e.g.
+	 * by bpf_sk_storage_free() during __sk_destruct().
+	 */
+	for (i = 0; i < (1U << smap->bucket_log); i++) {
+		b = &smap->buckets[i];
+
+		rcu_read_lock();
+		/* No one is adding to b->list now */
+		while ((selem = hlist_entry_safe(
+				rcu_dereference_raw(hlist_first_rcu(&b->list)),
+				struct bpf_local_storage_elem, map_node))) {
+			if (busy_counter) {
+				migrate_disable();
+				this_cpu_inc(*busy_counter);
+			}
+			bpf_selem_unlink(selem, false);
+			if (busy_counter) {
+				this_cpu_dec(*busy_counter);
+				migrate_enable();
+			}
+			cond_resched_rcu();
+		}
+		rcu_read_unlock();
+	}
+
+	/* While freeing the storage we may still need to access the map.
+	 *
+	 * e.g. when bpf_sk_storage_free() has unlinked selem from the map
+	 * which then made the above while((selem = ...)) loop
+	 * exit immediately.
+	 *
+	 * However, while freeing the storage one still needs to access the
+	 * smap->elem_size to do the uncharging in
+	 * bpf_selem_unlink_storage_nolock().
+	 *
+	 * Hence, wait another rcu grace period for the storage to be freed.
+	 */
+	synchronize_rcu();
+
+	kvfree(smap->buckets);
+	bpf_map_area_free(smap);
+}
+
+int bpf_local_storage_map_alloc_check(union bpf_attr *attr)
+{
+	if (attr->map_flags & ~BPF_LOCAL_STORAGE_CREATE_FLAG_MASK ||
+	    !(attr->map_flags & BPF_F_NO_PREALLOC) ||
+	    attr->max_entries ||
+	    attr->key_size != sizeof(int) || !attr->value_size ||
+	    /* Enforce BTF for userspace sk dumping */
+	    !attr->btf_key_type_id || !attr->btf_value_type_id)
+		return -EINVAL;
+
+	if (!bpf_capable())
+		return -EPERM;
+
+	if (attr->value_size > BPF_LOCAL_STORAGE_MAX_VALUE_SIZE)
+		return -E2BIG;
+
+	return 0;
+}
+
+struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_local_storage_map *smap;
+	unsigned int i;
+	u32 nbuckets;
+
+	smap = bpf_map_area_alloc(sizeof(*smap), NUMA_NO_NODE);
+	if (!smap)
+		return ERR_PTR(-ENOMEM);
+	bpf_map_init_from_attr(&smap->map, attr);
+
+	nbuckets = roundup_pow_of_two(num_possible_cpus());
+	/* Use at least 2 buckets, select_bucket() is undefined behavior with 1 bucket */
+	nbuckets = max_t(u32, 2, nbuckets);
+	smap->bucket_log = ilog2(nbuckets);
+
+	smap->buckets = kvcalloc(sizeof(*smap->buckets), nbuckets,
+				 GFP_USER | __GFP_NOWARN | __GFP_ACCOUNT);
+	if (!smap->buckets) {
+		bpf_map_area_free(smap);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	for (i = 0; i < nbuckets; i++) {
+		INIT_HLIST_HEAD(&smap->buckets[i].list);
+		raw_spin_lock_init(&smap->buckets[i].lock);
+	}
+
+	smap->elem_size =
+		sizeof(struct bpf_local_storage_elem) + attr->value_size;
+
+	return smap;
+}
+
+int bpf_local_storage_map_check_btf(const struct bpf_map *map,
+				    const struct btf *btf,
+				    const struct btf_type *key_type,
+				    const struct btf_type *value_type)
+{
+	u32 int_data;
+
+	if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
+		return -EINVAL;
+
+	int_data = *(u32 *)(key_type + 1);
+	if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data))
+		return -EINVAL;
+
+	return 0;
+}
diff --git a/kernel/bpf/bpf_lru_list.c b/kernel/bpf/bpf_lru_list.c
new file mode 100644
index 000000000..3dabdd137
--- /dev/null
+++ b/kernel/bpf/bpf_lru_list.c
@@ -0,0 +1,700 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2016 Facebook
+ */
+#include <linux/cpumask.h>
+#include <linux/spinlock.h>
+#include <linux/percpu.h>
+
+#include "bpf_lru_list.h"
+
+#define LOCAL_FREE_TARGET		(128)
+#define LOCAL_NR_SCANS			LOCAL_FREE_TARGET
+
+#define PERCPU_FREE_TARGET		(4)
+#define PERCPU_NR_SCANS			PERCPU_FREE_TARGET
+
+/* Helpers to get the local list index */
+#define LOCAL_LIST_IDX(t)	((t) - BPF_LOCAL_LIST_T_OFFSET)
+#define LOCAL_FREE_LIST_IDX	LOCAL_LIST_IDX(BPF_LRU_LOCAL_LIST_T_FREE)
+#define LOCAL_PENDING_LIST_IDX	LOCAL_LIST_IDX(BPF_LRU_LOCAL_LIST_T_PENDING)
+#define IS_LOCAL_LIST_TYPE(t)	((t) >= BPF_LOCAL_LIST_T_OFFSET)
+
+static int get_next_cpu(int cpu)
+{
+	cpu = cpumask_next(cpu, cpu_possible_mask);
+	if (cpu >= nr_cpu_ids)
+		cpu = cpumask_first(cpu_possible_mask);
+	return cpu;
+}
+
+/* Local list helpers */
+static struct list_head *local_free_list(struct bpf_lru_locallist *loc_l)
+{
+	return &loc_l->lists[LOCAL_FREE_LIST_IDX];
+}
+
+static struct list_head *local_pending_list(struct bpf_lru_locallist *loc_l)
+{
+	return &loc_l->lists[LOCAL_PENDING_LIST_IDX];
+}
+
+/* bpf_lru_node helpers */
+static bool bpf_lru_node_is_ref(const struct bpf_lru_node *node)
+{
+	return READ_ONCE(node->ref);
+}
+
+static void bpf_lru_node_clear_ref(struct bpf_lru_node *node)
+{
+	WRITE_ONCE(node->ref, 0);
+}
+
+static void bpf_lru_list_count_inc(struct bpf_lru_list *l,
+				   enum bpf_lru_list_type type)
+{
+	if (type < NR_BPF_LRU_LIST_COUNT)
+		l->counts[type]++;
+}
+
+static void bpf_lru_list_count_dec(struct bpf_lru_list *l,
+				   enum bpf_lru_list_type type)
+{
+	if (type < NR_BPF_LRU_LIST_COUNT)
+		l->counts[type]--;
+}
+
+static void __bpf_lru_node_move_to_free(struct bpf_lru_list *l,
+					struct bpf_lru_node *node,
+					struct list_head *free_list,
+					enum bpf_lru_list_type tgt_free_type)
+{
+	if (WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(node->type)))
+		return;
+
+	/* If the removing node is the next_inactive_rotation candidate,
+	 * move the next_inactive_rotation pointer also.
+	 */
+	if (&node->list == l->next_inactive_rotation)
+		l->next_inactive_rotation = l->next_inactive_rotation->prev;
+
+	bpf_lru_list_count_dec(l, node->type);
+
+	node->type = tgt_free_type;
+	list_move(&node->list, free_list);
+}
+
+/* Move nodes from local list to the LRU list */
+static void __bpf_lru_node_move_in(struct bpf_lru_list *l,
+				   struct bpf_lru_node *node,
+				   enum bpf_lru_list_type tgt_type)
+{
+	if (WARN_ON_ONCE(!IS_LOCAL_LIST_TYPE(node->type)) ||
+	    WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(tgt_type)))
+		return;
+
+	bpf_lru_list_count_inc(l, tgt_type);
+	node->type = tgt_type;
+	bpf_lru_node_clear_ref(node);
+	list_move(&node->list, &l->lists[tgt_type]);
+}
+
+/* Move nodes between or within active and inactive list (like
+ * active to inactive, inactive to active or tail of active back to
+ * the head of active).
+ */
+static void __bpf_lru_node_move(struct bpf_lru_list *l,
+				struct bpf_lru_node *node,
+				enum bpf_lru_list_type tgt_type)
+{
+	if (WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(node->type)) ||
+	    WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(tgt_type)))
+		return;
+
+	if (node->type != tgt_type) {
+		bpf_lru_list_count_dec(l, node->type);
+		bpf_lru_list_count_inc(l, tgt_type);
+		node->type = tgt_type;
+	}
+	bpf_lru_node_clear_ref(node);
+
+	/* If the moving node is the next_inactive_rotation candidate,
+	 * move the next_inactive_rotation pointer also.
+	 */
+	if (&node->list == l->next_inactive_rotation)
+		l->next_inactive_rotation = l->next_inactive_rotation->prev;
+
+	list_move(&node->list, &l->lists[tgt_type]);
+}
+
+static bool bpf_lru_list_inactive_low(const struct bpf_lru_list *l)
+{
+	return l->counts[BPF_LRU_LIST_T_INACTIVE] <
+		l->counts[BPF_LRU_LIST_T_ACTIVE];
+}
+
+/* Rotate the active list:
+ * 1. Start from tail
+ * 2. If the node has the ref bit set, it will be rotated
+ *    back to the head of active list with the ref bit cleared.
+ *    Give this node one more chance to survive in the active list.
+ * 3. If the ref bit is not set, move it to the head of the
+ *    inactive list.
+ * 4. It will at most scan nr_scans nodes
+ */
+static void __bpf_lru_list_rotate_active(struct bpf_lru *lru,
+					 struct bpf_lru_list *l)
+{
+	struct list_head *active = &l->lists[BPF_LRU_LIST_T_ACTIVE];
+	struct bpf_lru_node *node, *tmp_node, *first_node;
+	unsigned int i = 0;
+
+	first_node = list_first_entry(active, struct bpf_lru_node, list);
+	list_for_each_entry_safe_reverse(node, tmp_node, active, list) {
+		if (bpf_lru_node_is_ref(node))
+			__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_ACTIVE);
+		else
+			__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_INACTIVE);
+
+		if (++i == lru->nr_scans || node == first_node)
+			break;
+	}
+}
+
+/* Rotate the inactive list.  It starts from the next_inactive_rotation
+ * 1. If the node has ref bit set, it will be moved to the head
+ *    of active list with the ref bit cleared.
+ * 2. If the node does not have ref bit set, it will leave it
+ *    at its current location (i.e. do nothing) so that it can
+ *    be considered during the next inactive_shrink.
+ * 3. It will at most scan nr_scans nodes
+ */
+static void __bpf_lru_list_rotate_inactive(struct bpf_lru *lru,
+					   struct bpf_lru_list *l)
+{
+	struct list_head *inactive = &l->lists[BPF_LRU_LIST_T_INACTIVE];
+	struct list_head *cur, *last, *next = inactive;
+	struct bpf_lru_node *node;
+	unsigned int i = 0;
+
+	if (list_empty(inactive))
+		return;
+
+	last = l->next_inactive_rotation->next;
+	if (last == inactive)
+		last = last->next;
+
+	cur = l->next_inactive_rotation;
+	while (i < lru->nr_scans) {
+		if (cur == inactive) {
+			cur = cur->prev;
+			continue;
+		}
+
+		node = list_entry(cur, struct bpf_lru_node, list);
+		next = cur->prev;
+		if (bpf_lru_node_is_ref(node))
+			__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_ACTIVE);
+		if (cur == last)
+			break;
+		cur = next;
+		i++;
+	}
+
+	l->next_inactive_rotation = next;
+}
+
+/* Shrink the inactive list.  It starts from the tail of the
+ * inactive list and only move the nodes without the ref bit
+ * set to the designated free list.
+ */
+static unsigned int
+__bpf_lru_list_shrink_inactive(struct bpf_lru *lru,
+			       struct bpf_lru_list *l,
+			       unsigned int tgt_nshrink,
+			       struct list_head *free_list,
+			       enum bpf_lru_list_type tgt_free_type)
+{
+	struct list_head *inactive = &l->lists[BPF_LRU_LIST_T_INACTIVE];
+	struct bpf_lru_node *node, *tmp_node;
+	unsigned int nshrinked = 0;
+	unsigned int i = 0;
+
+	list_for_each_entry_safe_reverse(node, tmp_node, inactive, list) {
+		if (bpf_lru_node_is_ref(node)) {
+			__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_ACTIVE);
+		} else if (lru->del_from_htab(lru->del_arg, node)) {
+			__bpf_lru_node_move_to_free(l, node, free_list,
+						    tgt_free_type);
+			if (++nshrinked == tgt_nshrink)
+				break;
+		}
+
+		if (++i == lru->nr_scans)
+			break;
+	}
+
+	return nshrinked;
+}
+
+/* 1. Rotate the active list (if needed)
+ * 2. Always rotate the inactive list
+ */
+static void __bpf_lru_list_rotate(struct bpf_lru *lru, struct bpf_lru_list *l)
+{
+	if (bpf_lru_list_inactive_low(l))
+		__bpf_lru_list_rotate_active(lru, l);
+
+	__bpf_lru_list_rotate_inactive(lru, l);
+}
+
+/* Calls __bpf_lru_list_shrink_inactive() to shrink some
+ * ref-bit-cleared nodes and move them to the designated
+ * free list.
+ *
+ * If it cannot get a free node after calling
+ * __bpf_lru_list_shrink_inactive().  It will just remove
+ * one node from either inactive or active list without
+ * honoring the ref-bit.  It prefers inactive list to active
+ * list in this situation.
+ */
+static unsigned int __bpf_lru_list_shrink(struct bpf_lru *lru,
+					  struct bpf_lru_list *l,
+					  unsigned int tgt_nshrink,
+					  struct list_head *free_list,
+					  enum bpf_lru_list_type tgt_free_type)
+
+{
+	struct bpf_lru_node *node, *tmp_node;
+	struct list_head *force_shrink_list;
+	unsigned int nshrinked;
+
+	nshrinked = __bpf_lru_list_shrink_inactive(lru, l, tgt_nshrink,
+						   free_list, tgt_free_type);
+	if (nshrinked)
+		return nshrinked;
+
+	/* Do a force shrink by ignoring the reference bit */
+	if (!list_empty(&l->lists[BPF_LRU_LIST_T_INACTIVE]))
+		force_shrink_list = &l->lists[BPF_LRU_LIST_T_INACTIVE];
+	else
+		force_shrink_list = &l->lists[BPF_LRU_LIST_T_ACTIVE];
+
+	list_for_each_entry_safe_reverse(node, tmp_node, force_shrink_list,
+					 list) {
+		if (lru->del_from_htab(lru->del_arg, node)) {
+			__bpf_lru_node_move_to_free(l, node, free_list,
+						    tgt_free_type);
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+/* Flush the nodes from the local pending list to the LRU list */
+static void __local_list_flush(struct bpf_lru_list *l,
+			       struct bpf_lru_locallist *loc_l)
+{
+	struct bpf_lru_node *node, *tmp_node;
+
+	list_for_each_entry_safe_reverse(node, tmp_node,
+					 local_pending_list(loc_l), list) {
+		if (bpf_lru_node_is_ref(node))
+			__bpf_lru_node_move_in(l, node, BPF_LRU_LIST_T_ACTIVE);
+		else
+			__bpf_lru_node_move_in(l, node,
+					       BPF_LRU_LIST_T_INACTIVE);
+	}
+}
+
+static void bpf_lru_list_push_free(struct bpf_lru_list *l,
+				   struct bpf_lru_node *node)
+{
+	unsigned long flags;
+
+	if (WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(node->type)))
+		return;
+
+	raw_spin_lock_irqsave(&l->lock, flags);
+	__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_FREE);
+	raw_spin_unlock_irqrestore(&l->lock, flags);
+}
+
+static void bpf_lru_list_pop_free_to_local(struct bpf_lru *lru,
+					   struct bpf_lru_locallist *loc_l)
+{
+	struct bpf_lru_list *l = &lru->common_lru.lru_list;
+	struct bpf_lru_node *node, *tmp_node;
+	unsigned int nfree = 0;
+
+	raw_spin_lock(&l->lock);
+
+	__local_list_flush(l, loc_l);
+
+	__bpf_lru_list_rotate(lru, l);
+
+	list_for_each_entry_safe(node, tmp_node, &l->lists[BPF_LRU_LIST_T_FREE],
+				 list) {
+		__bpf_lru_node_move_to_free(l, node, local_free_list(loc_l),
+					    BPF_LRU_LOCAL_LIST_T_FREE);
+		if (++nfree == LOCAL_FREE_TARGET)
+			break;
+	}
+
+	if (nfree < LOCAL_FREE_TARGET)
+		__bpf_lru_list_shrink(lru, l, LOCAL_FREE_TARGET - nfree,
+				      local_free_list(loc_l),
+				      BPF_LRU_LOCAL_LIST_T_FREE);
+
+	raw_spin_unlock(&l->lock);
+}
+
+static void __local_list_add_pending(struct bpf_lru *lru,
+				     struct bpf_lru_locallist *loc_l,
+				     int cpu,
+				     struct bpf_lru_node *node,
+				     u32 hash)
+{
+	*(u32 *)((void *)node + lru->hash_offset) = hash;
+	node->cpu = cpu;
+	node->type = BPF_LRU_LOCAL_LIST_T_PENDING;
+	bpf_lru_node_clear_ref(node);
+	list_add(&node->list, local_pending_list(loc_l));
+}
+
+static struct bpf_lru_node *
+__local_list_pop_free(struct bpf_lru_locallist *loc_l)
+{
+	struct bpf_lru_node *node;
+
+	node = list_first_entry_or_null(local_free_list(loc_l),
+					struct bpf_lru_node,
+					list);
+	if (node)
+		list_del(&node->list);
+
+	return node;
+}
+
+static struct bpf_lru_node *
+__local_list_pop_pending(struct bpf_lru *lru, struct bpf_lru_locallist *loc_l)
+{
+	struct bpf_lru_node *node;
+	bool force = false;
+
+ignore_ref:
+	/* Get from the tail (i.e. older element) of the pending list. */
+	list_for_each_entry_reverse(node, local_pending_list(loc_l),
+				    list) {
+		if ((!bpf_lru_node_is_ref(node) || force) &&
+		    lru->del_from_htab(lru->del_arg, node)) {
+			list_del(&node->list);
+			return node;
+		}
+	}
+
+	if (!force) {
+		force = true;
+		goto ignore_ref;
+	}
+
+	return NULL;
+}
+
+static struct bpf_lru_node *bpf_percpu_lru_pop_free(struct bpf_lru *lru,
+						    u32 hash)
+{
+	struct list_head *free_list;
+	struct bpf_lru_node *node = NULL;
+	struct bpf_lru_list *l;
+	unsigned long flags;
+	int cpu = raw_smp_processor_id();
+
+	l = per_cpu_ptr(lru->percpu_lru, cpu);
+
+	raw_spin_lock_irqsave(&l->lock, flags);
+
+	__bpf_lru_list_rotate(lru, l);
+
+	free_list = &l->lists[BPF_LRU_LIST_T_FREE];
+	if (list_empty(free_list))
+		__bpf_lru_list_shrink(lru, l, PERCPU_FREE_TARGET, free_list,
+				      BPF_LRU_LIST_T_FREE);
+
+	if (!list_empty(free_list)) {
+		node = list_first_entry(free_list, struct bpf_lru_node, list);
+		*(u32 *)((void *)node + lru->hash_offset) = hash;
+		bpf_lru_node_clear_ref(node);
+		__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_INACTIVE);
+	}
+
+	raw_spin_unlock_irqrestore(&l->lock, flags);
+
+	return node;
+}
+
+static struct bpf_lru_node *bpf_common_lru_pop_free(struct bpf_lru *lru,
+						    u32 hash)
+{
+	struct bpf_lru_locallist *loc_l, *steal_loc_l;
+	struct bpf_common_lru *clru = &lru->common_lru;
+	struct bpf_lru_node *node;
+	int steal, first_steal;
+	unsigned long flags;
+	int cpu = raw_smp_processor_id();
+
+	loc_l = per_cpu_ptr(clru->local_list, cpu);
+
+	raw_spin_lock_irqsave(&loc_l->lock, flags);
+
+	node = __local_list_pop_free(loc_l);
+	if (!node) {
+		bpf_lru_list_pop_free_to_local(lru, loc_l);
+		node = __local_list_pop_free(loc_l);
+	}
+
+	if (node)
+		__local_list_add_pending(lru, loc_l, cpu, node, hash);
+
+	raw_spin_unlock_irqrestore(&loc_l->lock, flags);
+
+	if (node)
+		return node;
+
+	/* No free nodes found from the local free list and
+	 * the global LRU list.
+	 *
+	 * Steal from the local free/pending list of the
+	 * current CPU and remote CPU in RR.  It starts
+	 * with the loc_l->next_steal CPU.
+	 */
+
+	first_steal = loc_l->next_steal;
+	steal = first_steal;
+	do {
+		steal_loc_l = per_cpu_ptr(clru->local_list, steal);
+
+		raw_spin_lock_irqsave(&steal_loc_l->lock, flags);
+
+		node = __local_list_pop_free(steal_loc_l);
+		if (!node)
+			node = __local_list_pop_pending(lru, steal_loc_l);
+
+		raw_spin_unlock_irqrestore(&steal_loc_l->lock, flags);
+
+		steal = get_next_cpu(steal);
+	} while (!node && steal != first_steal);
+
+	loc_l->next_steal = steal;
+
+	if (node) {
+		raw_spin_lock_irqsave(&loc_l->lock, flags);
+		__local_list_add_pending(lru, loc_l, cpu, node, hash);
+		raw_spin_unlock_irqrestore(&loc_l->lock, flags);
+	}
+
+	return node;
+}
+
+struct bpf_lru_node *bpf_lru_pop_free(struct bpf_lru *lru, u32 hash)
+{
+	if (lru->percpu)
+		return bpf_percpu_lru_pop_free(lru, hash);
+	else
+		return bpf_common_lru_pop_free(lru, hash);
+}
+
+static void bpf_common_lru_push_free(struct bpf_lru *lru,
+				     struct bpf_lru_node *node)
+{
+	u8 node_type = READ_ONCE(node->type);
+	unsigned long flags;
+
+	if (WARN_ON_ONCE(node_type == BPF_LRU_LIST_T_FREE) ||
+	    WARN_ON_ONCE(node_type == BPF_LRU_LOCAL_LIST_T_FREE))
+		return;
+
+	if (node_type == BPF_LRU_LOCAL_LIST_T_PENDING) {
+		struct bpf_lru_locallist *loc_l;
+
+		loc_l = per_cpu_ptr(lru->common_lru.local_list, node->cpu);
+
+		raw_spin_lock_irqsave(&loc_l->lock, flags);
+
+		if (unlikely(node->type != BPF_LRU_LOCAL_LIST_T_PENDING)) {
+			raw_spin_unlock_irqrestore(&loc_l->lock, flags);
+			goto check_lru_list;
+		}
+
+		node->type = BPF_LRU_LOCAL_LIST_T_FREE;
+		bpf_lru_node_clear_ref(node);
+		list_move(&node->list, local_free_list(loc_l));
+
+		raw_spin_unlock_irqrestore(&loc_l->lock, flags);
+		return;
+	}
+
+check_lru_list:
+	bpf_lru_list_push_free(&lru->common_lru.lru_list, node);
+}
+
+static void bpf_percpu_lru_push_free(struct bpf_lru *lru,
+				     struct bpf_lru_node *node)
+{
+	struct bpf_lru_list *l;
+	unsigned long flags;
+
+	l = per_cpu_ptr(lru->percpu_lru, node->cpu);
+
+	raw_spin_lock_irqsave(&l->lock, flags);
+
+	__bpf_lru_node_move(l, node, BPF_LRU_LIST_T_FREE);
+
+	raw_spin_unlock_irqrestore(&l->lock, flags);
+}
+
+void bpf_lru_push_free(struct bpf_lru *lru, struct bpf_lru_node *node)
+{
+	if (lru->percpu)
+		bpf_percpu_lru_push_free(lru, node);
+	else
+		bpf_common_lru_push_free(lru, node);
+}
+
+static void bpf_common_lru_populate(struct bpf_lru *lru, void *buf,
+				    u32 node_offset, u32 elem_size,
+				    u32 nr_elems)
+{
+	struct bpf_lru_list *l = &lru->common_lru.lru_list;
+	u32 i;
+
+	for (i = 0; i < nr_elems; i++) {
+		struct bpf_lru_node *node;
+
+		node = (struct bpf_lru_node *)(buf + node_offset);
+		node->type = BPF_LRU_LIST_T_FREE;
+		bpf_lru_node_clear_ref(node);
+		list_add(&node->list, &l->lists[BPF_LRU_LIST_T_FREE]);
+		buf += elem_size;
+	}
+}
+
+static void bpf_percpu_lru_populate(struct bpf_lru *lru, void *buf,
+				    u32 node_offset, u32 elem_size,
+				    u32 nr_elems)
+{
+	u32 i, pcpu_entries;
+	int cpu;
+	struct bpf_lru_list *l;
+
+	pcpu_entries = nr_elems / num_possible_cpus();
+
+	i = 0;
+
+	for_each_possible_cpu(cpu) {
+		struct bpf_lru_node *node;
+
+		l = per_cpu_ptr(lru->percpu_lru, cpu);
+again:
+		node = (struct bpf_lru_node *)(buf + node_offset);
+		node->cpu = cpu;
+		node->type = BPF_LRU_LIST_T_FREE;
+		bpf_lru_node_clear_ref(node);
+		list_add(&node->list, &l->lists[BPF_LRU_LIST_T_FREE]);
+		i++;
+		buf += elem_size;
+		if (i == nr_elems)
+			break;
+		if (i % pcpu_entries)
+			goto again;
+	}
+}
+
+void bpf_lru_populate(struct bpf_lru *lru, void *buf, u32 node_offset,
+		      u32 elem_size, u32 nr_elems)
+{
+	if (lru->percpu)
+		bpf_percpu_lru_populate(lru, buf, node_offset, elem_size,
+					nr_elems);
+	else
+		bpf_common_lru_populate(lru, buf, node_offset, elem_size,
+					nr_elems);
+}
+
+static void bpf_lru_locallist_init(struct bpf_lru_locallist *loc_l, int cpu)
+{
+	int i;
+
+	for (i = 0; i < NR_BPF_LRU_LOCAL_LIST_T; i++)
+		INIT_LIST_HEAD(&loc_l->lists[i]);
+
+	loc_l->next_steal = cpu;
+
+	raw_spin_lock_init(&loc_l->lock);
+}
+
+static void bpf_lru_list_init(struct bpf_lru_list *l)
+{
+	int i;
+
+	for (i = 0; i < NR_BPF_LRU_LIST_T; i++)
+		INIT_LIST_HEAD(&l->lists[i]);
+
+	for (i = 0; i < NR_BPF_LRU_LIST_COUNT; i++)
+		l->counts[i] = 0;
+
+	l->next_inactive_rotation = &l->lists[BPF_LRU_LIST_T_INACTIVE];
+
+	raw_spin_lock_init(&l->lock);
+}
+
+int bpf_lru_init(struct bpf_lru *lru, bool percpu, u32 hash_offset,
+		 del_from_htab_func del_from_htab, void *del_arg)
+{
+	int cpu;
+
+	if (percpu) {
+		lru->percpu_lru = alloc_percpu(struct bpf_lru_list);
+		if (!lru->percpu_lru)
+			return -ENOMEM;
+
+		for_each_possible_cpu(cpu) {
+			struct bpf_lru_list *l;
+
+			l = per_cpu_ptr(lru->percpu_lru, cpu);
+			bpf_lru_list_init(l);
+		}
+		lru->nr_scans = PERCPU_NR_SCANS;
+	} else {
+		struct bpf_common_lru *clru = &lru->common_lru;
+
+		clru->local_list = alloc_percpu(struct bpf_lru_locallist);
+		if (!clru->local_list)
+			return -ENOMEM;
+
+		for_each_possible_cpu(cpu) {
+			struct bpf_lru_locallist *loc_l;
+
+			loc_l = per_cpu_ptr(clru->local_list, cpu);
+			bpf_lru_locallist_init(loc_l, cpu);
+		}
+
+		bpf_lru_list_init(&clru->lru_list);
+		lru->nr_scans = LOCAL_NR_SCANS;
+	}
+
+	lru->percpu = percpu;
+	lru->del_from_htab = del_from_htab;
+	lru->del_arg = del_arg;
+	lru->hash_offset = hash_offset;
+
+	return 0;
+}
+
+void bpf_lru_destroy(struct bpf_lru *lru)
+{
+	if (lru->percpu)
+		free_percpu(lru->percpu_lru);
+	else
+		free_percpu(lru->common_lru.local_list);
+}
diff --git a/kernel/bpf/bpf_lru_list.h b/kernel/bpf/bpf_lru_list.h
new file mode 100644
index 000000000..8f3c8b2b4
--- /dev/null
+++ b/kernel/bpf/bpf_lru_list.h
@@ -0,0 +1,80 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (c) 2016 Facebook
+ */
+#ifndef __BPF_LRU_LIST_H_
+#define __BPF_LRU_LIST_H_
+
+#include <linux/cache.h>
+#include <linux/list.h>
+#include <linux/spinlock_types.h>
+
+#define NR_BPF_LRU_LIST_T	(3)
+#define NR_BPF_LRU_LIST_COUNT	(2)
+#define NR_BPF_LRU_LOCAL_LIST_T (2)
+#define BPF_LOCAL_LIST_T_OFFSET NR_BPF_LRU_LIST_T
+
+enum bpf_lru_list_type {
+	BPF_LRU_LIST_T_ACTIVE,
+	BPF_LRU_LIST_T_INACTIVE,
+	BPF_LRU_LIST_T_FREE,
+	BPF_LRU_LOCAL_LIST_T_FREE,
+	BPF_LRU_LOCAL_LIST_T_PENDING,
+};
+
+struct bpf_lru_node {
+	struct list_head list;
+	u16 cpu;
+	u8 type;
+	u8 ref;
+};
+
+struct bpf_lru_list {
+	struct list_head lists[NR_BPF_LRU_LIST_T];
+	unsigned int counts[NR_BPF_LRU_LIST_COUNT];
+	/* The next inactive list rotation starts from here */
+	struct list_head *next_inactive_rotation;
+
+	raw_spinlock_t lock ____cacheline_aligned_in_smp;
+};
+
+struct bpf_lru_locallist {
+	struct list_head lists[NR_BPF_LRU_LOCAL_LIST_T];
+	u16 next_steal;
+	raw_spinlock_t lock;
+};
+
+struct bpf_common_lru {
+	struct bpf_lru_list lru_list;
+	struct bpf_lru_locallist __percpu *local_list;
+};
+
+typedef bool (*del_from_htab_func)(void *arg, struct bpf_lru_node *node);
+
+struct bpf_lru {
+	union {
+		struct bpf_common_lru common_lru;
+		struct bpf_lru_list __percpu *percpu_lru;
+	};
+	del_from_htab_func del_from_htab;
+	void *del_arg;
+	unsigned int hash_offset;
+	unsigned int nr_scans;
+	bool percpu;
+};
+
+static inline void bpf_lru_node_set_ref(struct bpf_lru_node *node)
+{
+	if (!READ_ONCE(node->ref))
+		WRITE_ONCE(node->ref, 1);
+}
+
+int bpf_lru_init(struct bpf_lru *lru, bool percpu, u32 hash_offset,
+		 del_from_htab_func del_from_htab, void *delete_arg);
+void bpf_lru_populate(struct bpf_lru *lru, void *buf, u32 node_offset,
+		      u32 elem_size, u32 nr_elems);
+void bpf_lru_destroy(struct bpf_lru *lru);
+struct bpf_lru_node *bpf_lru_pop_free(struct bpf_lru *lru, u32 hash);
+void bpf_lru_push_free(struct bpf_lru *lru, struct bpf_lru_node *node);
+void bpf_lru_promote(struct bpf_lru *lru, struct bpf_lru_node *node);
+
+#endif
diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c
new file mode 100644
index 000000000..e6a76da4b
--- /dev/null
+++ b/kernel/bpf/bpf_lsm.c
@@ -0,0 +1,356 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (C) 2020 Google LLC.
+ */
+
+#include <linux/filter.h>
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/binfmts.h>
+#include <linux/lsm_hooks.h>
+#include <linux/bpf_lsm.h>
+#include <linux/kallsyms.h>
+#include <linux/bpf_verifier.h>
+#include <net/bpf_sk_storage.h>
+#include <linux/bpf_local_storage.h>
+#include <linux/btf_ids.h>
+#include <linux/ima.h>
+#include <linux/bpf-cgroup.h>
+
+/* For every LSM hook that allows attachment of BPF programs, declare a nop
+ * function where a BPF program can be attached.
+ */
+#define LSM_HOOK(RET, DEFAULT, NAME, ...)	\
+noinline RET bpf_lsm_##NAME(__VA_ARGS__)	\
+{						\
+	return DEFAULT;				\
+}
+
+#include <linux/lsm_hook_defs.h>
+#undef LSM_HOOK
+
+#define LSM_HOOK(RET, DEFAULT, NAME, ...) BTF_ID(func, bpf_lsm_##NAME)
+BTF_SET_START(bpf_lsm_hooks)
+#include <linux/lsm_hook_defs.h>
+#undef LSM_HOOK
+BTF_SET_END(bpf_lsm_hooks)
+
+/* List of LSM hooks that should operate on 'current' cgroup regardless
+ * of function signature.
+ */
+BTF_SET_START(bpf_lsm_current_hooks)
+/* operate on freshly allocated sk without any cgroup association */
+#ifdef CONFIG_SECURITY_NETWORK
+BTF_ID(func, bpf_lsm_sk_alloc_security)
+BTF_ID(func, bpf_lsm_sk_free_security)
+#endif
+BTF_SET_END(bpf_lsm_current_hooks)
+
+/* List of LSM hooks that trigger while the socket is properly locked.
+ */
+BTF_SET_START(bpf_lsm_locked_sockopt_hooks)
+#ifdef CONFIG_SECURITY_NETWORK
+BTF_ID(func, bpf_lsm_sock_graft)
+BTF_ID(func, bpf_lsm_inet_csk_clone)
+BTF_ID(func, bpf_lsm_inet_conn_established)
+#endif
+BTF_SET_END(bpf_lsm_locked_sockopt_hooks)
+
+/* List of LSM hooks that trigger while the socket is _not_ locked,
+ * but it's ok to call bpf_{g,s}etsockopt because the socket is still
+ * in the early init phase.
+ */
+BTF_SET_START(bpf_lsm_unlocked_sockopt_hooks)
+#ifdef CONFIG_SECURITY_NETWORK
+BTF_ID(func, bpf_lsm_socket_post_create)
+BTF_ID(func, bpf_lsm_socket_socketpair)
+#endif
+BTF_SET_END(bpf_lsm_unlocked_sockopt_hooks)
+
+#ifdef CONFIG_CGROUP_BPF
+void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog,
+			     bpf_func_t *bpf_func)
+{
+	const struct btf_param *args __maybe_unused;
+
+	if (btf_type_vlen(prog->aux->attach_func_proto) < 1 ||
+	    btf_id_set_contains(&bpf_lsm_current_hooks,
+				prog->aux->attach_btf_id)) {
+		*bpf_func = __cgroup_bpf_run_lsm_current;
+		return;
+	}
+
+#ifdef CONFIG_NET
+	args = btf_params(prog->aux->attach_func_proto);
+
+	if (args[0].type == btf_sock_ids[BTF_SOCK_TYPE_SOCKET])
+		*bpf_func = __cgroup_bpf_run_lsm_socket;
+	else if (args[0].type == btf_sock_ids[BTF_SOCK_TYPE_SOCK])
+		*bpf_func = __cgroup_bpf_run_lsm_sock;
+	else
+#endif
+		*bpf_func = __cgroup_bpf_run_lsm_current;
+}
+#endif
+
+int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
+			const struct bpf_prog *prog)
+{
+	if (!prog->gpl_compatible) {
+		bpf_log(vlog,
+			"LSM programs must have a GPL compatible license\n");
+		return -EINVAL;
+	}
+
+	if (!btf_id_set_contains(&bpf_lsm_hooks, prog->aux->attach_btf_id)) {
+		bpf_log(vlog, "attach_btf_id %u points to wrong type name %s\n",
+			prog->aux->attach_btf_id, prog->aux->attach_func_name);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* Mask for all the currently supported BPRM option flags */
+#define BPF_F_BRPM_OPTS_MASK	BPF_F_BPRM_SECUREEXEC
+
+BPF_CALL_2(bpf_bprm_opts_set, struct linux_binprm *, bprm, u64, flags)
+{
+	if (flags & ~BPF_F_BRPM_OPTS_MASK)
+		return -EINVAL;
+
+	bprm->secureexec = (flags & BPF_F_BPRM_SECUREEXEC);
+	return 0;
+}
+
+BTF_ID_LIST_SINGLE(bpf_bprm_opts_set_btf_ids, struct, linux_binprm)
+
+static const struct bpf_func_proto bpf_bprm_opts_set_proto = {
+	.func		= bpf_bprm_opts_set,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_BTF_ID,
+	.arg1_btf_id	= &bpf_bprm_opts_set_btf_ids[0],
+	.arg2_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_3(bpf_ima_inode_hash, struct inode *, inode, void *, dst, u32, size)
+{
+	return ima_inode_hash(inode, dst, size);
+}
+
+static bool bpf_ima_inode_hash_allowed(const struct bpf_prog *prog)
+{
+	return bpf_lsm_is_sleepable_hook(prog->aux->attach_btf_id);
+}
+
+BTF_ID_LIST_SINGLE(bpf_ima_inode_hash_btf_ids, struct, inode)
+
+static const struct bpf_func_proto bpf_ima_inode_hash_proto = {
+	.func		= bpf_ima_inode_hash,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_BTF_ID,
+	.arg1_btf_id	= &bpf_ima_inode_hash_btf_ids[0],
+	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg3_type	= ARG_CONST_SIZE,
+	.allowed	= bpf_ima_inode_hash_allowed,
+};
+
+BPF_CALL_3(bpf_ima_file_hash, struct file *, file, void *, dst, u32, size)
+{
+	return ima_file_hash(file, dst, size);
+}
+
+BTF_ID_LIST_SINGLE(bpf_ima_file_hash_btf_ids, struct, file)
+
+static const struct bpf_func_proto bpf_ima_file_hash_proto = {
+	.func		= bpf_ima_file_hash,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_BTF_ID,
+	.arg1_btf_id	= &bpf_ima_file_hash_btf_ids[0],
+	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg3_type	= ARG_CONST_SIZE,
+	.allowed	= bpf_ima_inode_hash_allowed,
+};
+
+BPF_CALL_1(bpf_get_attach_cookie, void *, ctx)
+{
+	struct bpf_trace_run_ctx *run_ctx;
+
+	run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx);
+	return run_ctx->bpf_cookie;
+}
+
+static const struct bpf_func_proto bpf_get_attach_cookie_proto = {
+	.func		= bpf_get_attach_cookie,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+};
+
+static const struct bpf_func_proto *
+bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	const struct bpf_func_proto *func_proto;
+
+	if (prog->expected_attach_type == BPF_LSM_CGROUP) {
+		func_proto = cgroup_common_func_proto(func_id, prog);
+		if (func_proto)
+			return func_proto;
+	}
+
+	switch (func_id) {
+	case BPF_FUNC_inode_storage_get:
+		return &bpf_inode_storage_get_proto;
+	case BPF_FUNC_inode_storage_delete:
+		return &bpf_inode_storage_delete_proto;
+#ifdef CONFIG_NET
+	case BPF_FUNC_sk_storage_get:
+		return &bpf_sk_storage_get_proto;
+	case BPF_FUNC_sk_storage_delete:
+		return &bpf_sk_storage_delete_proto;
+#endif /* CONFIG_NET */
+	case BPF_FUNC_spin_lock:
+		return &bpf_spin_lock_proto;
+	case BPF_FUNC_spin_unlock:
+		return &bpf_spin_unlock_proto;
+	case BPF_FUNC_bprm_opts_set:
+		return &bpf_bprm_opts_set_proto;
+	case BPF_FUNC_ima_inode_hash:
+		return prog->aux->sleepable ? &bpf_ima_inode_hash_proto : NULL;
+	case BPF_FUNC_ima_file_hash:
+		return prog->aux->sleepable ? &bpf_ima_file_hash_proto : NULL;
+	case BPF_FUNC_get_attach_cookie:
+		return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto : NULL;
+#ifdef CONFIG_NET
+	case BPF_FUNC_setsockopt:
+		if (prog->expected_attach_type != BPF_LSM_CGROUP)
+			return NULL;
+		if (btf_id_set_contains(&bpf_lsm_locked_sockopt_hooks,
+					prog->aux->attach_btf_id))
+			return &bpf_sk_setsockopt_proto;
+		if (btf_id_set_contains(&bpf_lsm_unlocked_sockopt_hooks,
+					prog->aux->attach_btf_id))
+			return &bpf_unlocked_sk_setsockopt_proto;
+		return NULL;
+	case BPF_FUNC_getsockopt:
+		if (prog->expected_attach_type != BPF_LSM_CGROUP)
+			return NULL;
+		if (btf_id_set_contains(&bpf_lsm_locked_sockopt_hooks,
+					prog->aux->attach_btf_id))
+			return &bpf_sk_getsockopt_proto;
+		if (btf_id_set_contains(&bpf_lsm_unlocked_sockopt_hooks,
+					prog->aux->attach_btf_id))
+			return &bpf_unlocked_sk_getsockopt_proto;
+		return NULL;
+#endif
+	default:
+		return tracing_prog_func_proto(func_id, prog);
+	}
+}
+
+/* The set of hooks which are called without pagefaults disabled and are allowed
+ * to "sleep" and thus can be used for sleepable BPF programs.
+ */
+BTF_SET_START(sleepable_lsm_hooks)
+BTF_ID(func, bpf_lsm_bpf)
+BTF_ID(func, bpf_lsm_bpf_map)
+BTF_ID(func, bpf_lsm_bpf_map_alloc_security)
+BTF_ID(func, bpf_lsm_bpf_map_free_security)
+BTF_ID(func, bpf_lsm_bpf_prog)
+BTF_ID(func, bpf_lsm_bprm_check_security)
+BTF_ID(func, bpf_lsm_bprm_committed_creds)
+BTF_ID(func, bpf_lsm_bprm_committing_creds)
+BTF_ID(func, bpf_lsm_bprm_creds_for_exec)
+BTF_ID(func, bpf_lsm_bprm_creds_from_file)
+BTF_ID(func, bpf_lsm_capget)
+BTF_ID(func, bpf_lsm_capset)
+BTF_ID(func, bpf_lsm_cred_prepare)
+BTF_ID(func, bpf_lsm_file_ioctl)
+BTF_ID(func, bpf_lsm_file_lock)
+BTF_ID(func, bpf_lsm_file_open)
+BTF_ID(func, bpf_lsm_file_receive)
+
+#ifdef CONFIG_SECURITY_NETWORK
+BTF_ID(func, bpf_lsm_inet_conn_established)
+#endif /* CONFIG_SECURITY_NETWORK */
+
+BTF_ID(func, bpf_lsm_inode_create)
+BTF_ID(func, bpf_lsm_inode_free_security)
+BTF_ID(func, bpf_lsm_inode_getattr)
+BTF_ID(func, bpf_lsm_inode_getxattr)
+BTF_ID(func, bpf_lsm_inode_mknod)
+BTF_ID(func, bpf_lsm_inode_need_killpriv)
+BTF_ID(func, bpf_lsm_inode_post_setxattr)
+BTF_ID(func, bpf_lsm_inode_readlink)
+BTF_ID(func, bpf_lsm_inode_rename)
+BTF_ID(func, bpf_lsm_inode_rmdir)
+BTF_ID(func, bpf_lsm_inode_setattr)
+BTF_ID(func, bpf_lsm_inode_setxattr)
+BTF_ID(func, bpf_lsm_inode_symlink)
+BTF_ID(func, bpf_lsm_inode_unlink)
+BTF_ID(func, bpf_lsm_kernel_module_request)
+BTF_ID(func, bpf_lsm_kernel_read_file)
+BTF_ID(func, bpf_lsm_kernfs_init_security)
+
+#ifdef CONFIG_KEYS
+BTF_ID(func, bpf_lsm_key_free)
+#endif /* CONFIG_KEYS */
+
+BTF_ID(func, bpf_lsm_mmap_file)
+BTF_ID(func, bpf_lsm_netlink_send)
+BTF_ID(func, bpf_lsm_path_notify)
+BTF_ID(func, bpf_lsm_release_secctx)
+BTF_ID(func, bpf_lsm_sb_alloc_security)
+BTF_ID(func, bpf_lsm_sb_eat_lsm_opts)
+BTF_ID(func, bpf_lsm_sb_kern_mount)
+BTF_ID(func, bpf_lsm_sb_mount)
+BTF_ID(func, bpf_lsm_sb_remount)
+BTF_ID(func, bpf_lsm_sb_set_mnt_opts)
+BTF_ID(func, bpf_lsm_sb_show_options)
+BTF_ID(func, bpf_lsm_sb_statfs)
+BTF_ID(func, bpf_lsm_sb_umount)
+BTF_ID(func, bpf_lsm_settime)
+
+#ifdef CONFIG_SECURITY_NETWORK
+BTF_ID(func, bpf_lsm_socket_accept)
+BTF_ID(func, bpf_lsm_socket_bind)
+BTF_ID(func, bpf_lsm_socket_connect)
+BTF_ID(func, bpf_lsm_socket_create)
+BTF_ID(func, bpf_lsm_socket_getpeername)
+BTF_ID(func, bpf_lsm_socket_getpeersec_dgram)
+BTF_ID(func, bpf_lsm_socket_getsockname)
+BTF_ID(func, bpf_lsm_socket_getsockopt)
+BTF_ID(func, bpf_lsm_socket_listen)
+BTF_ID(func, bpf_lsm_socket_post_create)
+BTF_ID(func, bpf_lsm_socket_recvmsg)
+BTF_ID(func, bpf_lsm_socket_sendmsg)
+BTF_ID(func, bpf_lsm_socket_shutdown)
+BTF_ID(func, bpf_lsm_socket_socketpair)
+#endif /* CONFIG_SECURITY_NETWORK */
+
+BTF_ID(func, bpf_lsm_syslog)
+BTF_ID(func, bpf_lsm_task_alloc)
+BTF_ID(func, bpf_lsm_current_getsecid_subj)
+BTF_ID(func, bpf_lsm_task_getsecid_obj)
+BTF_ID(func, bpf_lsm_task_prctl)
+BTF_ID(func, bpf_lsm_task_setscheduler)
+BTF_ID(func, bpf_lsm_task_to_inode)
+BTF_ID(func, bpf_lsm_userns_create)
+BTF_SET_END(sleepable_lsm_hooks)
+
+bool bpf_lsm_is_sleepable_hook(u32 btf_id)
+{
+	return btf_id_set_contains(&sleepable_lsm_hooks, btf_id);
+}
+
+const struct bpf_prog_ops lsm_prog_ops = {
+};
+
+const struct bpf_verifier_ops lsm_verifier_ops = {
+	.get_func_proto = bpf_lsm_func_proto,
+	.is_valid_access = btf_ctx_access,
+};
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
new file mode 100644
index 000000000..84b2d9dba
--- /dev/null
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -0,0 +1,701 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2019 Facebook */
+
+#include <linux/bpf.h>
+#include <linux/bpf_verifier.h>
+#include <linux/btf.h>
+#include <linux/filter.h>
+#include <linux/slab.h>
+#include <linux/numa.h>
+#include <linux/seq_file.h>
+#include <linux/refcount.h>
+#include <linux/mutex.h>
+#include <linux/btf_ids.h>
+
+enum bpf_struct_ops_state {
+	BPF_STRUCT_OPS_STATE_INIT,
+	BPF_STRUCT_OPS_STATE_INUSE,
+	BPF_STRUCT_OPS_STATE_TOBEFREE,
+};
+
+#define BPF_STRUCT_OPS_COMMON_VALUE			\
+	refcount_t refcnt;				\
+	enum bpf_struct_ops_state state
+
+struct bpf_struct_ops_value {
+	BPF_STRUCT_OPS_COMMON_VALUE;
+	char data[] ____cacheline_aligned_in_smp;
+};
+
+struct bpf_struct_ops_map {
+	struct bpf_map map;
+	struct rcu_head rcu;
+	const struct bpf_struct_ops *st_ops;
+	/* protect map_update */
+	struct mutex lock;
+	/* link has all the bpf_links that is populated
+	 * to the func ptr of the kernel's struct
+	 * (in kvalue.data).
+	 */
+	struct bpf_link **links;
+	/* image is a page that has all the trampolines
+	 * that stores the func args before calling the bpf_prog.
+	 * A PAGE_SIZE "image" is enough to store all trampoline for
+	 * "links[]".
+	 */
+	void *image;
+	/* uvalue->data stores the kernel struct
+	 * (e.g. tcp_congestion_ops) that is more useful
+	 * to userspace than the kvalue.  For example,
+	 * the bpf_prog's id is stored instead of the kernel
+	 * address of a func ptr.
+	 */
+	struct bpf_struct_ops_value *uvalue;
+	/* kvalue.data stores the actual kernel's struct
+	 * (e.g. tcp_congestion_ops) that will be
+	 * registered to the kernel subsystem.
+	 */
+	struct bpf_struct_ops_value kvalue;
+};
+
+#define VALUE_PREFIX "bpf_struct_ops_"
+#define VALUE_PREFIX_LEN (sizeof(VALUE_PREFIX) - 1)
+
+/* bpf_struct_ops_##_name (e.g. bpf_struct_ops_tcp_congestion_ops) is
+ * the map's value exposed to the userspace and its btf-type-id is
+ * stored at the map->btf_vmlinux_value_type_id.
+ *
+ */
+#define BPF_STRUCT_OPS_TYPE(_name)				\
+extern struct bpf_struct_ops bpf_##_name;			\
+								\
+struct bpf_struct_ops_##_name {						\
+	BPF_STRUCT_OPS_COMMON_VALUE;				\
+	struct _name data ____cacheline_aligned_in_smp;		\
+};
+#include "bpf_struct_ops_types.h"
+#undef BPF_STRUCT_OPS_TYPE
+
+enum {
+#define BPF_STRUCT_OPS_TYPE(_name) BPF_STRUCT_OPS_TYPE_##_name,
+#include "bpf_struct_ops_types.h"
+#undef BPF_STRUCT_OPS_TYPE
+	__NR_BPF_STRUCT_OPS_TYPE,
+};
+
+static struct bpf_struct_ops * const bpf_struct_ops[] = {
+#define BPF_STRUCT_OPS_TYPE(_name)				\
+	[BPF_STRUCT_OPS_TYPE_##_name] = &bpf_##_name,
+#include "bpf_struct_ops_types.h"
+#undef BPF_STRUCT_OPS_TYPE
+};
+
+const struct bpf_verifier_ops bpf_struct_ops_verifier_ops = {
+};
+
+const struct bpf_prog_ops bpf_struct_ops_prog_ops = {
+#ifdef CONFIG_NET
+	.test_run = bpf_struct_ops_test_run,
+#endif
+};
+
+static const struct btf_type *module_type;
+
+void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
+{
+	s32 type_id, value_id, module_id;
+	const struct btf_member *member;
+	struct bpf_struct_ops *st_ops;
+	const struct btf_type *t;
+	char value_name[128];
+	const char *mname;
+	u32 i, j;
+
+	/* Ensure BTF type is emitted for "struct bpf_struct_ops_##_name" */
+#define BPF_STRUCT_OPS_TYPE(_name) BTF_TYPE_EMIT(struct bpf_struct_ops_##_name);
+#include "bpf_struct_ops_types.h"
+#undef BPF_STRUCT_OPS_TYPE
+
+	module_id = btf_find_by_name_kind(btf, "module", BTF_KIND_STRUCT);
+	if (module_id < 0) {
+		pr_warn("Cannot find struct module in btf_vmlinux\n");
+		return;
+	}
+	module_type = btf_type_by_id(btf, module_id);
+
+	for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
+		st_ops = bpf_struct_ops[i];
+
+		if (strlen(st_ops->name) + VALUE_PREFIX_LEN >=
+		    sizeof(value_name)) {
+			pr_warn("struct_ops name %s is too long\n",
+				st_ops->name);
+			continue;
+		}
+		sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
+
+		value_id = btf_find_by_name_kind(btf, value_name,
+						 BTF_KIND_STRUCT);
+		if (value_id < 0) {
+			pr_warn("Cannot find struct %s in btf_vmlinux\n",
+				value_name);
+			continue;
+		}
+
+		type_id = btf_find_by_name_kind(btf, st_ops->name,
+						BTF_KIND_STRUCT);
+		if (type_id < 0) {
+			pr_warn("Cannot find struct %s in btf_vmlinux\n",
+				st_ops->name);
+			continue;
+		}
+		t = btf_type_by_id(btf, type_id);
+		if (btf_type_vlen(t) > BPF_STRUCT_OPS_MAX_NR_MEMBERS) {
+			pr_warn("Cannot support #%u members in struct %s\n",
+				btf_type_vlen(t), st_ops->name);
+			continue;
+		}
+
+		for_each_member(j, t, member) {
+			const struct btf_type *func_proto;
+
+			mname = btf_name_by_offset(btf, member->name_off);
+			if (!*mname) {
+				pr_warn("anon member in struct %s is not supported\n",
+					st_ops->name);
+				break;
+			}
+
+			if (__btf_member_bitfield_size(t, member)) {
+				pr_warn("bit field member %s in struct %s is not supported\n",
+					mname, st_ops->name);
+				break;
+			}
+
+			func_proto = btf_type_resolve_func_ptr(btf,
+							       member->type,
+							       NULL);
+			if (func_proto &&
+			    btf_distill_func_proto(log, btf,
+						   func_proto, mname,
+						   &st_ops->func_models[j])) {
+				pr_warn("Error in parsing func ptr %s in struct %s\n",
+					mname, st_ops->name);
+				break;
+			}
+		}
+
+		if (j == btf_type_vlen(t)) {
+			if (st_ops->init(btf)) {
+				pr_warn("Error in init bpf_struct_ops %s\n",
+					st_ops->name);
+			} else {
+				st_ops->type_id = type_id;
+				st_ops->type = t;
+				st_ops->value_id = value_id;
+				st_ops->value_type = btf_type_by_id(btf,
+								    value_id);
+			}
+		}
+	}
+}
+
+extern struct btf *btf_vmlinux;
+
+static const struct bpf_struct_ops *
+bpf_struct_ops_find_value(u32 value_id)
+{
+	unsigned int i;
+
+	if (!value_id || !btf_vmlinux)
+		return NULL;
+
+	for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
+		if (bpf_struct_ops[i]->value_id == value_id)
+			return bpf_struct_ops[i];
+	}
+
+	return NULL;
+}
+
+const struct bpf_struct_ops *bpf_struct_ops_find(u32 type_id)
+{
+	unsigned int i;
+
+	if (!type_id || !btf_vmlinux)
+		return NULL;
+
+	for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
+		if (bpf_struct_ops[i]->type_id == type_id)
+			return bpf_struct_ops[i];
+	}
+
+	return NULL;
+}
+
+static int bpf_struct_ops_map_get_next_key(struct bpf_map *map, void *key,
+					   void *next_key)
+{
+	if (key && *(u32 *)key == 0)
+		return -ENOENT;
+
+	*(u32 *)next_key = 0;
+	return 0;
+}
+
+int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, void *key,
+				       void *value)
+{
+	struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map;
+	struct bpf_struct_ops_value *uvalue, *kvalue;
+	enum bpf_struct_ops_state state;
+
+	if (unlikely(*(u32 *)key != 0))
+		return -ENOENT;
+
+	kvalue = &st_map->kvalue;
+	/* Pair with smp_store_release() during map_update */
+	state = smp_load_acquire(&kvalue->state);
+	if (state == BPF_STRUCT_OPS_STATE_INIT) {
+		memset(value, 0, map->value_size);
+		return 0;
+	}
+
+	/* No lock is needed.  state and refcnt do not need
+	 * to be updated together under atomic context.
+	 */
+	uvalue = value;
+	memcpy(uvalue, st_map->uvalue, map->value_size);
+	uvalue->state = state;
+	refcount_set(&uvalue->refcnt, refcount_read(&kvalue->refcnt));
+
+	return 0;
+}
+
+static void *bpf_struct_ops_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static void bpf_struct_ops_map_put_progs(struct bpf_struct_ops_map *st_map)
+{
+	const struct btf_type *t = st_map->st_ops->type;
+	u32 i;
+
+	for (i = 0; i < btf_type_vlen(t); i++) {
+		if (st_map->links[i]) {
+			bpf_link_put(st_map->links[i]);
+			st_map->links[i] = NULL;
+		}
+	}
+}
+
+static int check_zero_holes(const struct btf_type *t, void *data)
+{
+	const struct btf_member *member;
+	u32 i, moff, msize, prev_mend = 0;
+	const struct btf_type *mtype;
+
+	for_each_member(i, t, member) {
+		moff = __btf_member_bit_offset(t, member) / 8;
+		if (moff > prev_mend &&
+		    memchr_inv(data + prev_mend, 0, moff - prev_mend))
+			return -EINVAL;
+
+		mtype = btf_type_by_id(btf_vmlinux, member->type);
+		mtype = btf_resolve_size(btf_vmlinux, mtype, &msize);
+		if (IS_ERR(mtype))
+			return PTR_ERR(mtype);
+		prev_mend = moff + msize;
+	}
+
+	if (t->size > prev_mend &&
+	    memchr_inv(data + prev_mend, 0, t->size - prev_mend))
+		return -EINVAL;
+
+	return 0;
+}
+
+static void bpf_struct_ops_link_release(struct bpf_link *link)
+{
+}
+
+static void bpf_struct_ops_link_dealloc(struct bpf_link *link)
+{
+	struct bpf_tramp_link *tlink = container_of(link, struct bpf_tramp_link, link);
+
+	kfree(tlink);
+}
+
+const struct bpf_link_ops bpf_struct_ops_link_lops = {
+	.release = bpf_struct_ops_link_release,
+	.dealloc = bpf_struct_ops_link_dealloc,
+};
+
+int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks,
+				      struct bpf_tramp_link *link,
+				      const struct btf_func_model *model,
+				      void *image, void *image_end)
+{
+	u32 flags;
+
+	tlinks[BPF_TRAMP_FENTRY].links[0] = link;
+	tlinks[BPF_TRAMP_FENTRY].nr_links = 1;
+	/* BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops,
+	 * and it must be used alone.
+	 */
+	flags = model->ret_size > 0 ? BPF_TRAMP_F_RET_FENTRY_RET : 0;
+	return arch_prepare_bpf_trampoline(NULL, image, image_end,
+					   model, flags, tlinks, NULL);
+}
+
+static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
+					  void *value, u64 flags)
+{
+	struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map;
+	const struct bpf_struct_ops *st_ops = st_map->st_ops;
+	struct bpf_struct_ops_value *uvalue, *kvalue;
+	const struct btf_member *member;
+	const struct btf_type *t = st_ops->type;
+	struct bpf_tramp_links *tlinks = NULL;
+	void *udata, *kdata;
+	int prog_fd, err = 0;
+	void *image, *image_end;
+	u32 i;
+
+	if (flags)
+		return -EINVAL;
+
+	if (*(u32 *)key != 0)
+		return -E2BIG;
+
+	err = check_zero_holes(st_ops->value_type, value);
+	if (err)
+		return err;
+
+	uvalue = value;
+	err = check_zero_holes(t, uvalue->data);
+	if (err)
+		return err;
+
+	if (uvalue->state || refcount_read(&uvalue->refcnt))
+		return -EINVAL;
+
+	tlinks = kcalloc(BPF_TRAMP_MAX, sizeof(*tlinks), GFP_KERNEL);
+	if (!tlinks)
+		return -ENOMEM;
+
+	uvalue = (struct bpf_struct_ops_value *)st_map->uvalue;
+	kvalue = (struct bpf_struct_ops_value *)&st_map->kvalue;
+
+	mutex_lock(&st_map->lock);
+
+	if (kvalue->state != BPF_STRUCT_OPS_STATE_INIT) {
+		err = -EBUSY;
+		goto unlock;
+	}
+
+	memcpy(uvalue, value, map->value_size);
+
+	udata = &uvalue->data;
+	kdata = &kvalue->data;
+	image = st_map->image;
+	image_end = st_map->image + PAGE_SIZE;
+
+	for_each_member(i, t, member) {
+		const struct btf_type *mtype, *ptype;
+		struct bpf_prog *prog;
+		struct bpf_tramp_link *link;
+		u32 moff;
+
+		moff = __btf_member_bit_offset(t, member) / 8;
+		ptype = btf_type_resolve_ptr(btf_vmlinux, member->type, NULL);
+		if (ptype == module_type) {
+			if (*(void **)(udata + moff))
+				goto reset_unlock;
+			*(void **)(kdata + moff) = BPF_MODULE_OWNER;
+			continue;
+		}
+
+		err = st_ops->init_member(t, member, kdata, udata);
+		if (err < 0)
+			goto reset_unlock;
+
+		/* The ->init_member() has handled this member */
+		if (err > 0)
+			continue;
+
+		/* If st_ops->init_member does not handle it,
+		 * we will only handle func ptrs and zero-ed members
+		 * here.  Reject everything else.
+		 */
+
+		/* All non func ptr member must be 0 */
+		if (!ptype || !btf_type_is_func_proto(ptype)) {
+			u32 msize;
+
+			mtype = btf_type_by_id(btf_vmlinux, member->type);
+			mtype = btf_resolve_size(btf_vmlinux, mtype, &msize);
+			if (IS_ERR(mtype)) {
+				err = PTR_ERR(mtype);
+				goto reset_unlock;
+			}
+
+			if (memchr_inv(udata + moff, 0, msize)) {
+				err = -EINVAL;
+				goto reset_unlock;
+			}
+
+			continue;
+		}
+
+		prog_fd = (int)(*(unsigned long *)(udata + moff));
+		/* Similar check as the attr->attach_prog_fd */
+		if (!prog_fd)
+			continue;
+
+		prog = bpf_prog_get(prog_fd);
+		if (IS_ERR(prog)) {
+			err = PTR_ERR(prog);
+			goto reset_unlock;
+		}
+
+		if (prog->type != BPF_PROG_TYPE_STRUCT_OPS ||
+		    prog->aux->attach_btf_id != st_ops->type_id ||
+		    prog->expected_attach_type != i) {
+			bpf_prog_put(prog);
+			err = -EINVAL;
+			goto reset_unlock;
+		}
+
+		link = kzalloc(sizeof(*link), GFP_USER);
+		if (!link) {
+			bpf_prog_put(prog);
+			err = -ENOMEM;
+			goto reset_unlock;
+		}
+		bpf_link_init(&link->link, BPF_LINK_TYPE_STRUCT_OPS,
+			      &bpf_struct_ops_link_lops, prog);
+		st_map->links[i] = &link->link;
+
+		err = bpf_struct_ops_prepare_trampoline(tlinks, link,
+							&st_ops->func_models[i],
+							image, image_end);
+		if (err < 0)
+			goto reset_unlock;
+
+		*(void **)(kdata + moff) = image;
+		image += err;
+
+		/* put prog_id to udata */
+		*(unsigned long *)(udata + moff) = prog->aux->id;
+	}
+
+	refcount_set(&kvalue->refcnt, 1);
+	bpf_map_inc(map);
+
+	set_memory_ro((long)st_map->image, 1);
+	set_memory_x((long)st_map->image, 1);
+	err = st_ops->reg(kdata);
+	if (likely(!err)) {
+		/* Pair with smp_load_acquire() during lookup_elem().
+		 * It ensures the above udata updates (e.g. prog->aux->id)
+		 * can be seen once BPF_STRUCT_OPS_STATE_INUSE is set.
+		 */
+		smp_store_release(&kvalue->state, BPF_STRUCT_OPS_STATE_INUSE);
+		goto unlock;
+	}
+
+	/* Error during st_ops->reg(). Can happen if this struct_ops needs to be
+	 * verified as a whole, after all init_member() calls. Can also happen if
+	 * there was a race in registering the struct_ops (under the same name) to
+	 * a sub-system through different struct_ops's maps.
+	 */
+	set_memory_nx((long)st_map->image, 1);
+	set_memory_rw((long)st_map->image, 1);
+	bpf_map_put(map);
+
+reset_unlock:
+	bpf_struct_ops_map_put_progs(st_map);
+	memset(uvalue, 0, map->value_size);
+	memset(kvalue, 0, map->value_size);
+unlock:
+	kfree(tlinks);
+	mutex_unlock(&st_map->lock);
+	return err;
+}
+
+static int bpf_struct_ops_map_delete_elem(struct bpf_map *map, void *key)
+{
+	enum bpf_struct_ops_state prev_state;
+	struct bpf_struct_ops_map *st_map;
+
+	st_map = (struct bpf_struct_ops_map *)map;
+	prev_state = cmpxchg(&st_map->kvalue.state,
+			     BPF_STRUCT_OPS_STATE_INUSE,
+			     BPF_STRUCT_OPS_STATE_TOBEFREE);
+	switch (prev_state) {
+	case BPF_STRUCT_OPS_STATE_INUSE:
+		st_map->st_ops->unreg(&st_map->kvalue.data);
+		if (refcount_dec_and_test(&st_map->kvalue.refcnt))
+			bpf_map_put(map);
+		return 0;
+	case BPF_STRUCT_OPS_STATE_TOBEFREE:
+		return -EINPROGRESS;
+	case BPF_STRUCT_OPS_STATE_INIT:
+		return -ENOENT;
+	default:
+		WARN_ON_ONCE(1);
+		/* Should never happen.  Treat it as not found. */
+		return -ENOENT;
+	}
+}
+
+static void bpf_struct_ops_map_seq_show_elem(struct bpf_map *map, void *key,
+					     struct seq_file *m)
+{
+	void *value;
+	int err;
+
+	value = kmalloc(map->value_size, GFP_USER | __GFP_NOWARN);
+	if (!value)
+		return;
+
+	err = bpf_struct_ops_map_sys_lookup_elem(map, key, value);
+	if (!err) {
+		btf_type_seq_show(btf_vmlinux, map->btf_vmlinux_value_type_id,
+				  value, m);
+		seq_puts(m, "\n");
+	}
+
+	kfree(value);
+}
+
+static void bpf_struct_ops_map_free(struct bpf_map *map)
+{
+	struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map;
+
+	if (st_map->links)
+		bpf_struct_ops_map_put_progs(st_map);
+	bpf_map_area_free(st_map->links);
+	bpf_jit_free_exec(st_map->image);
+	bpf_map_area_free(st_map->uvalue);
+	bpf_map_area_free(st_map);
+}
+
+static int bpf_struct_ops_map_alloc_check(union bpf_attr *attr)
+{
+	if (attr->key_size != sizeof(unsigned int) || attr->max_entries != 1 ||
+	    attr->map_flags || !attr->btf_vmlinux_value_type_id)
+		return -EINVAL;
+	return 0;
+}
+
+static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr)
+{
+	const struct bpf_struct_ops *st_ops;
+	size_t st_map_size;
+	struct bpf_struct_ops_map *st_map;
+	const struct btf_type *t, *vt;
+	struct bpf_map *map;
+
+	if (!bpf_capable())
+		return ERR_PTR(-EPERM);
+
+	st_ops = bpf_struct_ops_find_value(attr->btf_vmlinux_value_type_id);
+	if (!st_ops)
+		return ERR_PTR(-ENOTSUPP);
+
+	vt = st_ops->value_type;
+	if (attr->value_size != vt->size)
+		return ERR_PTR(-EINVAL);
+
+	t = st_ops->type;
+
+	st_map_size = sizeof(*st_map) +
+		/* kvalue stores the
+		 * struct bpf_struct_ops_tcp_congestions_ops
+		 */
+		(vt->size - sizeof(struct bpf_struct_ops_value));
+
+	st_map = bpf_map_area_alloc(st_map_size, NUMA_NO_NODE);
+	if (!st_map)
+		return ERR_PTR(-ENOMEM);
+
+	st_map->st_ops = st_ops;
+	map = &st_map->map;
+
+	st_map->uvalue = bpf_map_area_alloc(vt->size, NUMA_NO_NODE);
+	st_map->links =
+		bpf_map_area_alloc(btf_type_vlen(t) * sizeof(struct bpf_links *),
+				   NUMA_NO_NODE);
+	st_map->image = bpf_jit_alloc_exec(PAGE_SIZE);
+	if (!st_map->uvalue || !st_map->links || !st_map->image) {
+		bpf_struct_ops_map_free(map);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	mutex_init(&st_map->lock);
+	set_vm_flush_reset_perms(st_map->image);
+	bpf_map_init_from_attr(map, attr);
+
+	return map;
+}
+
+BTF_ID_LIST_SINGLE(bpf_struct_ops_map_btf_ids, struct, bpf_struct_ops_map)
+const struct bpf_map_ops bpf_struct_ops_map_ops = {
+	.map_alloc_check = bpf_struct_ops_map_alloc_check,
+	.map_alloc = bpf_struct_ops_map_alloc,
+	.map_free = bpf_struct_ops_map_free,
+	.map_get_next_key = bpf_struct_ops_map_get_next_key,
+	.map_lookup_elem = bpf_struct_ops_map_lookup_elem,
+	.map_delete_elem = bpf_struct_ops_map_delete_elem,
+	.map_update_elem = bpf_struct_ops_map_update_elem,
+	.map_seq_show_elem = bpf_struct_ops_map_seq_show_elem,
+	.map_btf_id = &bpf_struct_ops_map_btf_ids[0],
+};
+
+/* "const void *" because some subsystem is
+ * passing a const (e.g. const struct tcp_congestion_ops *)
+ */
+bool bpf_struct_ops_get(const void *kdata)
+{
+	struct bpf_struct_ops_value *kvalue;
+
+	kvalue = container_of(kdata, struct bpf_struct_ops_value, data);
+
+	return refcount_inc_not_zero(&kvalue->refcnt);
+}
+
+static void bpf_struct_ops_put_rcu(struct rcu_head *head)
+{
+	struct bpf_struct_ops_map *st_map;
+
+	st_map = container_of(head, struct bpf_struct_ops_map, rcu);
+	bpf_map_put(&st_map->map);
+}
+
+void bpf_struct_ops_put(const void *kdata)
+{
+	struct bpf_struct_ops_value *kvalue;
+
+	kvalue = container_of(kdata, struct bpf_struct_ops_value, data);
+	if (refcount_dec_and_test(&kvalue->refcnt)) {
+		struct bpf_struct_ops_map *st_map;
+
+		st_map = container_of(kvalue, struct bpf_struct_ops_map,
+				      kvalue);
+		/* The struct_ops's function may switch to another struct_ops.
+		 *
+		 * For example, bpf_tcp_cc_x->init() may switch to
+		 * another tcp_cc_y by calling
+		 * setsockopt(TCP_CONGESTION, "tcp_cc_y").
+		 * During the switch,  bpf_struct_ops_put(tcp_cc_x) is called
+		 * and its map->refcnt may reach 0 which then free its
+		 * trampoline image while tcp_cc_x is still running.
+		 *
+		 * Thus, a rcu grace period is needed here.
+		 */
+		call_rcu(&st_map->rcu, bpf_struct_ops_put_rcu);
+	}
+}
diff --git a/kernel/bpf/bpf_struct_ops_types.h b/kernel/bpf/bpf_struct_ops_types.h
new file mode 100644
index 000000000..5678a9ddf
--- /dev/null
+++ b/kernel/bpf/bpf_struct_ops_types.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* internal file - do not include directly */
+
+#ifdef CONFIG_BPF_JIT
+#ifdef CONFIG_NET
+BPF_STRUCT_OPS_TYPE(bpf_dummy_ops)
+#endif
+#ifdef CONFIG_INET
+#include <net/tcp.h>
+BPF_STRUCT_OPS_TYPE(tcp_congestion_ops)
+#endif
+#endif
diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c
new file mode 100644
index 000000000..6f2906233
--- /dev/null
+++ b/kernel/bpf/bpf_task_storage.c
@@ -0,0 +1,343 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2020 Facebook
+ * Copyright 2020 Google LLC.
+ */
+
+#include <linux/pid.h>
+#include <linux/sched.h>
+#include <linux/rculist.h>
+#include <linux/list.h>
+#include <linux/hash.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/bpf.h>
+#include <linux/bpf_local_storage.h>
+#include <linux/filter.h>
+#include <uapi/linux/btf.h>
+#include <linux/btf_ids.h>
+#include <linux/fdtable.h>
+#include <linux/rcupdate_trace.h>
+
+DEFINE_BPF_STORAGE_CACHE(task_cache);
+
+static DEFINE_PER_CPU(int, bpf_task_storage_busy);
+
+static void bpf_task_storage_lock(void)
+{
+	migrate_disable();
+	this_cpu_inc(bpf_task_storage_busy);
+}
+
+static void bpf_task_storage_unlock(void)
+{
+	this_cpu_dec(bpf_task_storage_busy);
+	migrate_enable();
+}
+
+static bool bpf_task_storage_trylock(void)
+{
+	migrate_disable();
+	if (unlikely(this_cpu_inc_return(bpf_task_storage_busy) != 1)) {
+		this_cpu_dec(bpf_task_storage_busy);
+		migrate_enable();
+		return false;
+	}
+	return true;
+}
+
+static struct bpf_local_storage __rcu **task_storage_ptr(void *owner)
+{
+	struct task_struct *task = owner;
+
+	return &task->bpf_storage;
+}
+
+static struct bpf_local_storage_data *
+task_storage_lookup(struct task_struct *task, struct bpf_map *map,
+		    bool cacheit_lockit)
+{
+	struct bpf_local_storage *task_storage;
+	struct bpf_local_storage_map *smap;
+
+	task_storage =
+		rcu_dereference_check(task->bpf_storage, bpf_rcu_lock_held());
+	if (!task_storage)
+		return NULL;
+
+	smap = (struct bpf_local_storage_map *)map;
+	return bpf_local_storage_lookup(task_storage, smap, cacheit_lockit);
+}
+
+void bpf_task_storage_free(struct task_struct *task)
+{
+	struct bpf_local_storage_elem *selem;
+	struct bpf_local_storage *local_storage;
+	bool free_task_storage = false;
+	struct hlist_node *n;
+	unsigned long flags;
+
+	rcu_read_lock();
+
+	local_storage = rcu_dereference(task->bpf_storage);
+	if (!local_storage) {
+		rcu_read_unlock();
+		return;
+	}
+
+	/* Neither the bpf_prog nor the bpf-map's syscall
+	 * could be modifying the local_storage->list now.
+	 * Thus, no elem can be added-to or deleted-from the
+	 * local_storage->list by the bpf_prog or by the bpf-map's syscall.
+	 *
+	 * It is racing with bpf_local_storage_map_free() alone
+	 * when unlinking elem from the local_storage->list and
+	 * the map's bucket->list.
+	 */
+	bpf_task_storage_lock();
+	raw_spin_lock_irqsave(&local_storage->lock, flags);
+	hlist_for_each_entry_safe(selem, n, &local_storage->list, snode) {
+		/* Always unlink from map before unlinking from
+		 * local_storage.
+		 */
+		bpf_selem_unlink_map(selem);
+		free_task_storage = bpf_selem_unlink_storage_nolock(
+			local_storage, selem, false, false);
+	}
+	raw_spin_unlock_irqrestore(&local_storage->lock, flags);
+	bpf_task_storage_unlock();
+	rcu_read_unlock();
+
+	/* free_task_storage should always be true as long as
+	 * local_storage->list was non-empty.
+	 */
+	if (free_task_storage)
+		kfree_rcu(local_storage, rcu);
+}
+
+static void *bpf_pid_task_storage_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_local_storage_data *sdata;
+	struct task_struct *task;
+	unsigned int f_flags;
+	struct pid *pid;
+	int fd, err;
+
+	fd = *(int *)key;
+	pid = pidfd_get_pid(fd, &f_flags);
+	if (IS_ERR(pid))
+		return ERR_CAST(pid);
+
+	/* We should be in an RCU read side critical section, it should be safe
+	 * to call pid_task.
+	 */
+	WARN_ON_ONCE(!rcu_read_lock_held());
+	task = pid_task(pid, PIDTYPE_PID);
+	if (!task) {
+		err = -ENOENT;
+		goto out;
+	}
+
+	bpf_task_storage_lock();
+	sdata = task_storage_lookup(task, map, true);
+	bpf_task_storage_unlock();
+	put_pid(pid);
+	return sdata ? sdata->data : NULL;
+out:
+	put_pid(pid);
+	return ERR_PTR(err);
+}
+
+static int bpf_pid_task_storage_update_elem(struct bpf_map *map, void *key,
+					    void *value, u64 map_flags)
+{
+	struct bpf_local_storage_data *sdata;
+	struct task_struct *task;
+	unsigned int f_flags;
+	struct pid *pid;
+	int fd, err;
+
+	fd = *(int *)key;
+	pid = pidfd_get_pid(fd, &f_flags);
+	if (IS_ERR(pid))
+		return PTR_ERR(pid);
+
+	/* We should be in an RCU read side critical section, it should be safe
+	 * to call pid_task.
+	 */
+	WARN_ON_ONCE(!rcu_read_lock_held());
+	task = pid_task(pid, PIDTYPE_PID);
+	if (!task) {
+		err = -ENOENT;
+		goto out;
+	}
+
+	bpf_task_storage_lock();
+	sdata = bpf_local_storage_update(
+		task, (struct bpf_local_storage_map *)map, value, map_flags,
+		GFP_ATOMIC);
+	bpf_task_storage_unlock();
+
+	err = PTR_ERR_OR_ZERO(sdata);
+out:
+	put_pid(pid);
+	return err;
+}
+
+static int task_storage_delete(struct task_struct *task, struct bpf_map *map)
+{
+	struct bpf_local_storage_data *sdata;
+
+	sdata = task_storage_lookup(task, map, false);
+	if (!sdata)
+		return -ENOENT;
+
+	bpf_selem_unlink(SELEM(sdata), true);
+
+	return 0;
+}
+
+static int bpf_pid_task_storage_delete_elem(struct bpf_map *map, void *key)
+{
+	struct task_struct *task;
+	unsigned int f_flags;
+	struct pid *pid;
+	int fd, err;
+
+	fd = *(int *)key;
+	pid = pidfd_get_pid(fd, &f_flags);
+	if (IS_ERR(pid))
+		return PTR_ERR(pid);
+
+	/* We should be in an RCU read side critical section, it should be safe
+	 * to call pid_task.
+	 */
+	WARN_ON_ONCE(!rcu_read_lock_held());
+	task = pid_task(pid, PIDTYPE_PID);
+	if (!task) {
+		err = -ENOENT;
+		goto out;
+	}
+
+	bpf_task_storage_lock();
+	err = task_storage_delete(task, map);
+	bpf_task_storage_unlock();
+out:
+	put_pid(pid);
+	return err;
+}
+
+/* *gfp_flags* is a hidden argument provided by the verifier */
+BPF_CALL_5(bpf_task_storage_get, struct bpf_map *, map, struct task_struct *,
+	   task, void *, value, u64, flags, gfp_t, gfp_flags)
+{
+	struct bpf_local_storage_data *sdata;
+
+	WARN_ON_ONCE(!bpf_rcu_lock_held());
+	if (flags & ~(BPF_LOCAL_STORAGE_GET_F_CREATE))
+		return (unsigned long)NULL;
+
+	if (!task)
+		return (unsigned long)NULL;
+
+	if (!bpf_task_storage_trylock())
+		return (unsigned long)NULL;
+
+	sdata = task_storage_lookup(task, map, true);
+	if (sdata)
+		goto unlock;
+
+	/* only allocate new storage, when the task is refcounted */
+	if (refcount_read(&task->usage) &&
+	    (flags & BPF_LOCAL_STORAGE_GET_F_CREATE))
+		sdata = bpf_local_storage_update(
+			task, (struct bpf_local_storage_map *)map, value,
+			BPF_NOEXIST, gfp_flags);
+
+unlock:
+	bpf_task_storage_unlock();
+	return IS_ERR_OR_NULL(sdata) ? (unsigned long)NULL :
+		(unsigned long)sdata->data;
+}
+
+BPF_CALL_2(bpf_task_storage_delete, struct bpf_map *, map, struct task_struct *,
+	   task)
+{
+	int ret;
+
+	WARN_ON_ONCE(!bpf_rcu_lock_held());
+	if (!task)
+		return -EINVAL;
+
+	if (!bpf_task_storage_trylock())
+		return -EBUSY;
+
+	/* This helper must only be called from places where the lifetime of the task
+	 * is guaranteed. Either by being refcounted or by being protected
+	 * by an RCU read-side critical section.
+	 */
+	ret = task_storage_delete(task, map);
+	bpf_task_storage_unlock();
+	return ret;
+}
+
+static int notsupp_get_next_key(struct bpf_map *map, void *key, void *next_key)
+{
+	return -ENOTSUPP;
+}
+
+static struct bpf_map *task_storage_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_local_storage_map *smap;
+
+	smap = bpf_local_storage_map_alloc(attr);
+	if (IS_ERR(smap))
+		return ERR_CAST(smap);
+
+	smap->cache_idx = bpf_local_storage_cache_idx_get(&task_cache);
+	return &smap->map;
+}
+
+static void task_storage_map_free(struct bpf_map *map)
+{
+	struct bpf_local_storage_map *smap;
+
+	smap = (struct bpf_local_storage_map *)map;
+	bpf_local_storage_cache_idx_free(&task_cache, smap->cache_idx);
+	bpf_local_storage_map_free(smap, &bpf_task_storage_busy);
+}
+
+BTF_ID_LIST_SINGLE(task_storage_map_btf_ids, struct, bpf_local_storage_map)
+const struct bpf_map_ops task_storage_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = bpf_local_storage_map_alloc_check,
+	.map_alloc = task_storage_map_alloc,
+	.map_free = task_storage_map_free,
+	.map_get_next_key = notsupp_get_next_key,
+	.map_lookup_elem = bpf_pid_task_storage_lookup_elem,
+	.map_update_elem = bpf_pid_task_storage_update_elem,
+	.map_delete_elem = bpf_pid_task_storage_delete_elem,
+	.map_check_btf = bpf_local_storage_map_check_btf,
+	.map_btf_id = &task_storage_map_btf_ids[0],
+	.map_owner_storage_ptr = task_storage_ptr,
+};
+
+const struct bpf_func_proto bpf_task_storage_get_proto = {
+	.func = bpf_task_storage_get,
+	.gpl_only = false,
+	.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
+	.arg1_type = ARG_CONST_MAP_PTR,
+	.arg2_type = ARG_PTR_TO_BTF_ID,
+	.arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
+	.arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
+	.arg4_type = ARG_ANYTHING,
+};
+
+const struct bpf_func_proto bpf_task_storage_delete_proto = {
+	.func = bpf_task_storage_delete,
+	.gpl_only = false,
+	.ret_type = RET_INTEGER,
+	.arg1_type = ARG_CONST_MAP_PTR,
+	.arg2_type = ARG_PTR_TO_BTF_ID,
+	.arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
+};
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
new file mode 100644
index 000000000..7582ec4fd
--- /dev/null
+++ b/kernel/bpf/btf.c
@@ -0,0 +1,8035 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2018 Facebook */
+
+#include <uapi/linux/btf.h>
+#include <uapi/linux/bpf.h>
+#include <uapi/linux/bpf_perf_event.h>
+#include <uapi/linux/types.h>
+#include <linux/seq_file.h>
+#include <linux/compiler.h>
+#include <linux/ctype.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/idr.h>
+#include <linux/sort.h>
+#include <linux/bpf_verifier.h>
+#include <linux/btf.h>
+#include <linux/btf_ids.h>
+#include <linux/skmsg.h>
+#include <linux/perf_event.h>
+#include <linux/bsearch.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+#include <net/sock.h>
+#include "../tools/lib/bpf/relo_core.h"
+
+/* BTF (BPF Type Format) is the meta data format which describes
+ * the data types of BPF program/map.  Hence, it basically focus
+ * on the C programming language which the modern BPF is primary
+ * using.
+ *
+ * ELF Section:
+ * ~~~~~~~~~~~
+ * The BTF data is stored under the ".BTF" ELF section
+ *
+ * struct btf_type:
+ * ~~~~~~~~~~~~~~~
+ * Each 'struct btf_type' object describes a C data type.
+ * Depending on the type it is describing, a 'struct btf_type'
+ * object may be followed by more data.  F.e.
+ * To describe an array, 'struct btf_type' is followed by
+ * 'struct btf_array'.
+ *
+ * 'struct btf_type' and any extra data following it are
+ * 4 bytes aligned.
+ *
+ * Type section:
+ * ~~~~~~~~~~~~~
+ * The BTF type section contains a list of 'struct btf_type' objects.
+ * Each one describes a C type.  Recall from the above section
+ * that a 'struct btf_type' object could be immediately followed by extra
+ * data in order to describe some particular C types.
+ *
+ * type_id:
+ * ~~~~~~~
+ * Each btf_type object is identified by a type_id.  The type_id
+ * is implicitly implied by the location of the btf_type object in
+ * the BTF type section.  The first one has type_id 1.  The second
+ * one has type_id 2...etc.  Hence, an earlier btf_type has
+ * a smaller type_id.
+ *
+ * A btf_type object may refer to another btf_type object by using
+ * type_id (i.e. the "type" in the "struct btf_type").
+ *
+ * NOTE that we cannot assume any reference-order.
+ * A btf_type object can refer to an earlier btf_type object
+ * but it can also refer to a later btf_type object.
+ *
+ * For example, to describe "const void *".  A btf_type
+ * object describing "const" may refer to another btf_type
+ * object describing "void *".  This type-reference is done
+ * by specifying type_id:
+ *
+ * [1] CONST (anon) type_id=2
+ * [2] PTR (anon) type_id=0
+ *
+ * The above is the btf_verifier debug log:
+ *   - Each line started with "[?]" is a btf_type object
+ *   - [?] is the type_id of the btf_type object.
+ *   - CONST/PTR is the BTF_KIND_XXX
+ *   - "(anon)" is the name of the type.  It just
+ *     happens that CONST and PTR has no name.
+ *   - type_id=XXX is the 'u32 type' in btf_type
+ *
+ * NOTE: "void" has type_id 0
+ *
+ * String section:
+ * ~~~~~~~~~~~~~~
+ * The BTF string section contains the names used by the type section.
+ * Each string is referred by an "offset" from the beginning of the
+ * string section.
+ *
+ * Each string is '\0' terminated.
+ *
+ * The first character in the string section must be '\0'
+ * which is used to mean 'anonymous'. Some btf_type may not
+ * have a name.
+ */
+
+/* BTF verification:
+ *
+ * To verify BTF data, two passes are needed.
+ *
+ * Pass #1
+ * ~~~~~~~
+ * The first pass is to collect all btf_type objects to
+ * an array: "btf->types".
+ *
+ * Depending on the C type that a btf_type is describing,
+ * a btf_type may be followed by extra data.  We don't know
+ * how many btf_type is there, and more importantly we don't
+ * know where each btf_type is located in the type section.
+ *
+ * Without knowing the location of each type_id, most verifications
+ * cannot be done.  e.g. an earlier btf_type may refer to a later
+ * btf_type (recall the "const void *" above), so we cannot
+ * check this type-reference in the first pass.
+ *
+ * In the first pass, it still does some verifications (e.g.
+ * checking the name is a valid offset to the string section).
+ *
+ * Pass #2
+ * ~~~~~~~
+ * The main focus is to resolve a btf_type that is referring
+ * to another type.
+ *
+ * We have to ensure the referring type:
+ * 1) does exist in the BTF (i.e. in btf->types[])
+ * 2) does not cause a loop:
+ *	struct A {
+ *		struct B b;
+ *	};
+ *
+ *	struct B {
+ *		struct A a;
+ *	};
+ *
+ * btf_type_needs_resolve() decides if a btf_type needs
+ * to be resolved.
+ *
+ * The needs_resolve type implements the "resolve()" ops which
+ * essentially does a DFS and detects backedge.
+ *
+ * During resolve (or DFS), different C types have different
+ * "RESOLVED" conditions.
+ *
+ * When resolving a BTF_KIND_STRUCT, we need to resolve all its
+ * members because a member is always referring to another
+ * type.  A struct's member can be treated as "RESOLVED" if
+ * it is referring to a BTF_KIND_PTR.  Otherwise, the
+ * following valid C struct would be rejected:
+ *
+ *	struct A {
+ *		int m;
+ *		struct A *a;
+ *	};
+ *
+ * When resolving a BTF_KIND_PTR, it needs to keep resolving if
+ * it is referring to another BTF_KIND_PTR.  Otherwise, we cannot
+ * detect a pointer loop, e.g.:
+ * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
+ *                        ^                                         |
+ *                        +-----------------------------------------+
+ *
+ */
+
+#define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
+#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
+#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
+#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
+#define BITS_ROUNDUP_BYTES(bits) \
+	(BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
+
+#define BTF_INFO_MASK 0x9f00ffff
+#define BTF_INT_MASK 0x0fffffff
+#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
+#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
+
+/* 16MB for 64k structs and each has 16 members and
+ * a few MB spaces for the string section.
+ * The hard limit is S32_MAX.
+ */
+#define BTF_MAX_SIZE (16 * 1024 * 1024)
+
+#define for_each_member_from(i, from, struct_type, member)		\
+	for (i = from, member = btf_type_member(struct_type) + from;	\
+	     i < btf_type_vlen(struct_type);				\
+	     i++, member++)
+
+#define for_each_vsi_from(i, from, struct_type, member)				\
+	for (i = from, member = btf_type_var_secinfo(struct_type) + from;	\
+	     i < btf_type_vlen(struct_type);					\
+	     i++, member++)
+
+DEFINE_IDR(btf_idr);
+DEFINE_SPINLOCK(btf_idr_lock);
+
+enum btf_kfunc_hook {
+	BTF_KFUNC_HOOK_XDP,
+	BTF_KFUNC_HOOK_TC,
+	BTF_KFUNC_HOOK_STRUCT_OPS,
+	BTF_KFUNC_HOOK_TRACING,
+	BTF_KFUNC_HOOK_SYSCALL,
+	BTF_KFUNC_HOOK_MAX,
+};
+
+enum {
+	BTF_KFUNC_SET_MAX_CNT = 256,
+	BTF_DTOR_KFUNC_MAX_CNT = 256,
+};
+
+struct btf_kfunc_set_tab {
+	struct btf_id_set8 *sets[BTF_KFUNC_HOOK_MAX];
+};
+
+struct btf_id_dtor_kfunc_tab {
+	u32 cnt;
+	struct btf_id_dtor_kfunc dtors[];
+};
+
+struct btf {
+	void *data;
+	struct btf_type **types;
+	u32 *resolved_ids;
+	u32 *resolved_sizes;
+	const char *strings;
+	void *nohdr_data;
+	struct btf_header hdr;
+	u32 nr_types; /* includes VOID for base BTF */
+	u32 types_size;
+	u32 data_size;
+	refcount_t refcnt;
+	u32 id;
+	struct rcu_head rcu;
+	struct btf_kfunc_set_tab *kfunc_set_tab;
+	struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab;
+
+	/* split BTF support */
+	struct btf *base_btf;
+	u32 start_id; /* first type ID in this BTF (0 for base BTF) */
+	u32 start_str_off; /* first string offset (0 for base BTF) */
+	char name[MODULE_NAME_LEN];
+	bool kernel_btf;
+};
+
+enum verifier_phase {
+	CHECK_META,
+	CHECK_TYPE,
+};
+
+struct resolve_vertex {
+	const struct btf_type *t;
+	u32 type_id;
+	u16 next_member;
+};
+
+enum visit_state {
+	NOT_VISITED,
+	VISITED,
+	RESOLVED,
+};
+
+enum resolve_mode {
+	RESOLVE_TBD,	/* To Be Determined */
+	RESOLVE_PTR,	/* Resolving for Pointer */
+	RESOLVE_STRUCT_OR_ARRAY,	/* Resolving for struct/union
+					 * or array
+					 */
+};
+
+#define MAX_RESOLVE_DEPTH 32
+
+struct btf_sec_info {
+	u32 off;
+	u32 len;
+};
+
+struct btf_verifier_env {
+	struct btf *btf;
+	u8 *visit_states;
+	struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
+	struct bpf_verifier_log log;
+	u32 log_type_id;
+	u32 top_stack;
+	enum verifier_phase phase;
+	enum resolve_mode resolve_mode;
+};
+
+static const char * const btf_kind_str[NR_BTF_KINDS] = {
+	[BTF_KIND_UNKN]		= "UNKNOWN",
+	[BTF_KIND_INT]		= "INT",
+	[BTF_KIND_PTR]		= "PTR",
+	[BTF_KIND_ARRAY]	= "ARRAY",
+	[BTF_KIND_STRUCT]	= "STRUCT",
+	[BTF_KIND_UNION]	= "UNION",
+	[BTF_KIND_ENUM]		= "ENUM",
+	[BTF_KIND_FWD]		= "FWD",
+	[BTF_KIND_TYPEDEF]	= "TYPEDEF",
+	[BTF_KIND_VOLATILE]	= "VOLATILE",
+	[BTF_KIND_CONST]	= "CONST",
+	[BTF_KIND_RESTRICT]	= "RESTRICT",
+	[BTF_KIND_FUNC]		= "FUNC",
+	[BTF_KIND_FUNC_PROTO]	= "FUNC_PROTO",
+	[BTF_KIND_VAR]		= "VAR",
+	[BTF_KIND_DATASEC]	= "DATASEC",
+	[BTF_KIND_FLOAT]	= "FLOAT",
+	[BTF_KIND_DECL_TAG]	= "DECL_TAG",
+	[BTF_KIND_TYPE_TAG]	= "TYPE_TAG",
+	[BTF_KIND_ENUM64]	= "ENUM64",
+};
+
+const char *btf_type_str(const struct btf_type *t)
+{
+	return btf_kind_str[BTF_INFO_KIND(t->info)];
+}
+
+/* Chunk size we use in safe copy of data to be shown. */
+#define BTF_SHOW_OBJ_SAFE_SIZE		32
+
+/*
+ * This is the maximum size of a base type value (equivalent to a
+ * 128-bit int); if we are at the end of our safe buffer and have
+ * less than 16 bytes space we can't be assured of being able
+ * to copy the next type safely, so in such cases we will initiate
+ * a new copy.
+ */
+#define BTF_SHOW_OBJ_BASE_TYPE_SIZE	16
+
+/* Type name size */
+#define BTF_SHOW_NAME_SIZE		80
+
+/*
+ * Common data to all BTF show operations. Private show functions can add
+ * their own data to a structure containing a struct btf_show and consult it
+ * in the show callback.  See btf_type_show() below.
+ *
+ * One challenge with showing nested data is we want to skip 0-valued
+ * data, but in order to figure out whether a nested object is all zeros
+ * we need to walk through it.  As a result, we need to make two passes
+ * when handling structs, unions and arrays; the first path simply looks
+ * for nonzero data, while the second actually does the display.  The first
+ * pass is signalled by show->state.depth_check being set, and if we
+ * encounter a non-zero value we set show->state.depth_to_show to
+ * the depth at which we encountered it.  When we have completed the
+ * first pass, we will know if anything needs to be displayed if
+ * depth_to_show > depth.  See btf_[struct,array]_show() for the
+ * implementation of this.
+ *
+ * Another problem is we want to ensure the data for display is safe to
+ * access.  To support this, the anonymous "struct {} obj" tracks the data
+ * object and our safe copy of it.  We copy portions of the data needed
+ * to the object "copy" buffer, but because its size is limited to
+ * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
+ * traverse larger objects for display.
+ *
+ * The various data type show functions all start with a call to
+ * btf_show_start_type() which returns a pointer to the safe copy
+ * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
+ * raw data itself).  btf_show_obj_safe() is responsible for
+ * using copy_from_kernel_nofault() to update the safe data if necessary
+ * as we traverse the object's data.  skbuff-like semantics are
+ * used:
+ *
+ * - obj.head points to the start of the toplevel object for display
+ * - obj.size is the size of the toplevel object
+ * - obj.data points to the current point in the original data at
+ *   which our safe data starts.  obj.data will advance as we copy
+ *   portions of the data.
+ *
+ * In most cases a single copy will suffice, but larger data structures
+ * such as "struct task_struct" will require many copies.  The logic in
+ * btf_show_obj_safe() handles the logic that determines if a new
+ * copy_from_kernel_nofault() is needed.
+ */
+struct btf_show {
+	u64 flags;
+	void *target;	/* target of show operation (seq file, buffer) */
+	void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
+	const struct btf *btf;
+	/* below are used during iteration */
+	struct {
+		u8 depth;
+		u8 depth_to_show;
+		u8 depth_check;
+		u8 array_member:1,
+		   array_terminated:1;
+		u16 array_encoding;
+		u32 type_id;
+		int status;			/* non-zero for error */
+		const struct btf_type *type;
+		const struct btf_member *member;
+		char name[BTF_SHOW_NAME_SIZE];	/* space for member name/type */
+	} state;
+	struct {
+		u32 size;
+		void *head;
+		void *data;
+		u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
+	} obj;
+};
+
+struct btf_kind_operations {
+	s32 (*check_meta)(struct btf_verifier_env *env,
+			  const struct btf_type *t,
+			  u32 meta_left);
+	int (*resolve)(struct btf_verifier_env *env,
+		       const struct resolve_vertex *v);
+	int (*check_member)(struct btf_verifier_env *env,
+			    const struct btf_type *struct_type,
+			    const struct btf_member *member,
+			    const struct btf_type *member_type);
+	int (*check_kflag_member)(struct btf_verifier_env *env,
+				  const struct btf_type *struct_type,
+				  const struct btf_member *member,
+				  const struct btf_type *member_type);
+	void (*log_details)(struct btf_verifier_env *env,
+			    const struct btf_type *t);
+	void (*show)(const struct btf *btf, const struct btf_type *t,
+			 u32 type_id, void *data, u8 bits_offsets,
+			 struct btf_show *show);
+};
+
+static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
+static struct btf_type btf_void;
+
+static int btf_resolve(struct btf_verifier_env *env,
+		       const struct btf_type *t, u32 type_id);
+
+static int btf_func_check(struct btf_verifier_env *env,
+			  const struct btf_type *t);
+
+static bool btf_type_is_modifier(const struct btf_type *t)
+{
+	/* Some of them is not strictly a C modifier
+	 * but they are grouped into the same bucket
+	 * for BTF concern:
+	 *   A type (t) that refers to another
+	 *   type through t->type AND its size cannot
+	 *   be determined without following the t->type.
+	 *
+	 * ptr does not fall into this bucket
+	 * because its size is always sizeof(void *).
+	 */
+	switch (BTF_INFO_KIND(t->info)) {
+	case BTF_KIND_TYPEDEF:
+	case BTF_KIND_VOLATILE:
+	case BTF_KIND_CONST:
+	case BTF_KIND_RESTRICT:
+	case BTF_KIND_TYPE_TAG:
+		return true;
+	}
+
+	return false;
+}
+
+bool btf_type_is_void(const struct btf_type *t)
+{
+	return t == &btf_void;
+}
+
+static bool btf_type_is_fwd(const struct btf_type *t)
+{
+	return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
+}
+
+static bool btf_type_nosize(const struct btf_type *t)
+{
+	return btf_type_is_void(t) || btf_type_is_fwd(t) ||
+	       btf_type_is_func(t) || btf_type_is_func_proto(t);
+}
+
+static bool btf_type_nosize_or_null(const struct btf_type *t)
+{
+	return !t || btf_type_nosize(t);
+}
+
+static bool __btf_type_is_struct(const struct btf_type *t)
+{
+	return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
+}
+
+static bool btf_type_is_array(const struct btf_type *t)
+{
+	return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
+}
+
+static bool btf_type_is_datasec(const struct btf_type *t)
+{
+	return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
+}
+
+static bool btf_type_is_decl_tag(const struct btf_type *t)
+{
+	return BTF_INFO_KIND(t->info) == BTF_KIND_DECL_TAG;
+}
+
+static bool btf_type_is_decl_tag_target(const struct btf_type *t)
+{
+	return btf_type_is_func(t) || btf_type_is_struct(t) ||
+	       btf_type_is_var(t) || btf_type_is_typedef(t);
+}
+
+u32 btf_nr_types(const struct btf *btf)
+{
+	u32 total = 0;
+
+	while (btf) {
+		total += btf->nr_types;
+		btf = btf->base_btf;
+	}
+
+	return total;
+}
+
+s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
+{
+	const struct btf_type *t;
+	const char *tname;
+	u32 i, total;
+
+	total = btf_nr_types(btf);
+	for (i = 1; i < total; i++) {
+		t = btf_type_by_id(btf, i);
+		if (BTF_INFO_KIND(t->info) != kind)
+			continue;
+
+		tname = btf_name_by_offset(btf, t->name_off);
+		if (!strcmp(tname, name))
+			return i;
+	}
+
+	return -ENOENT;
+}
+
+static s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
+{
+	struct btf *btf;
+	s32 ret;
+	int id;
+
+	btf = bpf_get_btf_vmlinux();
+	if (IS_ERR(btf))
+		return PTR_ERR(btf);
+	if (!btf)
+		return -EINVAL;
+
+	ret = btf_find_by_name_kind(btf, name, kind);
+	/* ret is never zero, since btf_find_by_name_kind returns
+	 * positive btf_id or negative error.
+	 */
+	if (ret > 0) {
+		btf_get(btf);
+		*btf_p = btf;
+		return ret;
+	}
+
+	/* If name is not found in vmlinux's BTF then search in module's BTFs */
+	spin_lock_bh(&btf_idr_lock);
+	idr_for_each_entry(&btf_idr, btf, id) {
+		if (!btf_is_module(btf))
+			continue;
+		/* linear search could be slow hence unlock/lock
+		 * the IDR to avoiding holding it for too long
+		 */
+		btf_get(btf);
+		spin_unlock_bh(&btf_idr_lock);
+		ret = btf_find_by_name_kind(btf, name, kind);
+		if (ret > 0) {
+			*btf_p = btf;
+			return ret;
+		}
+		btf_put(btf);
+		spin_lock_bh(&btf_idr_lock);
+	}
+	spin_unlock_bh(&btf_idr_lock);
+	return ret;
+}
+
+const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
+					       u32 id, u32 *res_id)
+{
+	const struct btf_type *t = btf_type_by_id(btf, id);
+
+	while (btf_type_is_modifier(t)) {
+		id = t->type;
+		t = btf_type_by_id(btf, t->type);
+	}
+
+	if (res_id)
+		*res_id = id;
+
+	return t;
+}
+
+const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
+					    u32 id, u32 *res_id)
+{
+	const struct btf_type *t;
+
+	t = btf_type_skip_modifiers(btf, id, NULL);
+	if (!btf_type_is_ptr(t))
+		return NULL;
+
+	return btf_type_skip_modifiers(btf, t->type, res_id);
+}
+
+const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
+						 u32 id, u32 *res_id)
+{
+	const struct btf_type *ptype;
+
+	ptype = btf_type_resolve_ptr(btf, id, res_id);
+	if (ptype && btf_type_is_func_proto(ptype))
+		return ptype;
+
+	return NULL;
+}
+
+/* Types that act only as a source, not sink or intermediate
+ * type when resolving.
+ */
+static bool btf_type_is_resolve_source_only(const struct btf_type *t)
+{
+	return btf_type_is_var(t) ||
+	       btf_type_is_decl_tag(t) ||
+	       btf_type_is_datasec(t);
+}
+
+/* What types need to be resolved?
+ *
+ * btf_type_is_modifier() is an obvious one.
+ *
+ * btf_type_is_struct() because its member refers to
+ * another type (through member->type).
+ *
+ * btf_type_is_var() because the variable refers to
+ * another type. btf_type_is_datasec() holds multiple
+ * btf_type_is_var() types that need resolving.
+ *
+ * btf_type_is_array() because its element (array->type)
+ * refers to another type.  Array can be thought of a
+ * special case of struct while array just has the same
+ * member-type repeated by array->nelems of times.
+ */
+static bool btf_type_needs_resolve(const struct btf_type *t)
+{
+	return btf_type_is_modifier(t) ||
+	       btf_type_is_ptr(t) ||
+	       btf_type_is_struct(t) ||
+	       btf_type_is_array(t) ||
+	       btf_type_is_var(t) ||
+	       btf_type_is_func(t) ||
+	       btf_type_is_decl_tag(t) ||
+	       btf_type_is_datasec(t);
+}
+
+/* t->size can be used */
+static bool btf_type_has_size(const struct btf_type *t)
+{
+	switch (BTF_INFO_KIND(t->info)) {
+	case BTF_KIND_INT:
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION:
+	case BTF_KIND_ENUM:
+	case BTF_KIND_DATASEC:
+	case BTF_KIND_FLOAT:
+	case BTF_KIND_ENUM64:
+		return true;
+	}
+
+	return false;
+}
+
+static const char *btf_int_encoding_str(u8 encoding)
+{
+	if (encoding == 0)
+		return "(none)";
+	else if (encoding == BTF_INT_SIGNED)
+		return "SIGNED";
+	else if (encoding == BTF_INT_CHAR)
+		return "CHAR";
+	else if (encoding == BTF_INT_BOOL)
+		return "BOOL";
+	else
+		return "UNKN";
+}
+
+static u32 btf_type_int(const struct btf_type *t)
+{
+	return *(u32 *)(t + 1);
+}
+
+static const struct btf_array *btf_type_array(const struct btf_type *t)
+{
+	return (const struct btf_array *)(t + 1);
+}
+
+static const struct btf_enum *btf_type_enum(const struct btf_type *t)
+{
+	return (const struct btf_enum *)(t + 1);
+}
+
+static const struct btf_var *btf_type_var(const struct btf_type *t)
+{
+	return (const struct btf_var *)(t + 1);
+}
+
+static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
+{
+	return (const struct btf_decl_tag *)(t + 1);
+}
+
+static const struct btf_enum64 *btf_type_enum64(const struct btf_type *t)
+{
+	return (const struct btf_enum64 *)(t + 1);
+}
+
+static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
+{
+	return kind_ops[BTF_INFO_KIND(t->info)];
+}
+
+static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
+{
+	if (!BTF_STR_OFFSET_VALID(offset))
+		return false;
+
+	while (offset < btf->start_str_off)
+		btf = btf->base_btf;
+
+	offset -= btf->start_str_off;
+	return offset < btf->hdr.str_len;
+}
+
+static bool __btf_name_char_ok(char c, bool first)
+{
+	if ((first ? !isalpha(c) :
+		     !isalnum(c)) &&
+	    c != '_' &&
+	    c != '.')
+		return false;
+	return true;
+}
+
+static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
+{
+	while (offset < btf->start_str_off)
+		btf = btf->base_btf;
+
+	offset -= btf->start_str_off;
+	if (offset < btf->hdr.str_len)
+		return &btf->strings[offset];
+
+	return NULL;
+}
+
+static bool __btf_name_valid(const struct btf *btf, u32 offset)
+{
+	/* offset must be valid */
+	const char *src = btf_str_by_offset(btf, offset);
+	const char *src_limit;
+
+	if (!__btf_name_char_ok(*src, true))
+		return false;
+
+	/* set a limit on identifier length */
+	src_limit = src + KSYM_NAME_LEN;
+	src++;
+	while (*src && src < src_limit) {
+		if (!__btf_name_char_ok(*src, false))
+			return false;
+		src++;
+	}
+
+	return !*src;
+}
+
+static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
+{
+	return __btf_name_valid(btf, offset);
+}
+
+static bool btf_name_valid_section(const struct btf *btf, u32 offset)
+{
+	return __btf_name_valid(btf, offset);
+}
+
+static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
+{
+	const char *name;
+
+	if (!offset)
+		return "(anon)";
+
+	name = btf_str_by_offset(btf, offset);
+	return name ?: "(invalid-name-offset)";
+}
+
+const char *btf_name_by_offset(const struct btf *btf, u32 offset)
+{
+	return btf_str_by_offset(btf, offset);
+}
+
+const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
+{
+	while (type_id < btf->start_id)
+		btf = btf->base_btf;
+
+	type_id -= btf->start_id;
+	if (type_id >= btf->nr_types)
+		return NULL;
+	return btf->types[type_id];
+}
+EXPORT_SYMBOL_GPL(btf_type_by_id);
+
+/*
+ * Regular int is not a bit field and it must be either
+ * u8/u16/u32/u64 or __int128.
+ */
+static bool btf_type_int_is_regular(const struct btf_type *t)
+{
+	u8 nr_bits, nr_bytes;
+	u32 int_data;
+
+	int_data = btf_type_int(t);
+	nr_bits = BTF_INT_BITS(int_data);
+	nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
+	if (BITS_PER_BYTE_MASKED(nr_bits) ||
+	    BTF_INT_OFFSET(int_data) ||
+	    (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
+	     nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
+	     nr_bytes != (2 * sizeof(u64)))) {
+		return false;
+	}
+
+	return true;
+}
+
+/*
+ * Check that given struct member is a regular int with expected
+ * offset and size.
+ */
+bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
+			   const struct btf_member *m,
+			   u32 expected_offset, u32 expected_size)
+{
+	const struct btf_type *t;
+	u32 id, int_data;
+	u8 nr_bits;
+
+	id = m->type;
+	t = btf_type_id_size(btf, &id, NULL);
+	if (!t || !btf_type_is_int(t))
+		return false;
+
+	int_data = btf_type_int(t);
+	nr_bits = BTF_INT_BITS(int_data);
+	if (btf_type_kflag(s)) {
+		u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
+		u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
+
+		/* if kflag set, int should be a regular int and
+		 * bit offset should be at byte boundary.
+		 */
+		return !bitfield_size &&
+		       BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
+		       BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
+	}
+
+	if (BTF_INT_OFFSET(int_data) ||
+	    BITS_PER_BYTE_MASKED(m->offset) ||
+	    BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
+	    BITS_PER_BYTE_MASKED(nr_bits) ||
+	    BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
+		return false;
+
+	return true;
+}
+
+/* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
+static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
+						       u32 id)
+{
+	const struct btf_type *t = btf_type_by_id(btf, id);
+
+	while (btf_type_is_modifier(t) &&
+	       BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
+		t = btf_type_by_id(btf, t->type);
+	}
+
+	return t;
+}
+
+#define BTF_SHOW_MAX_ITER	10
+
+#define BTF_KIND_BIT(kind)	(1ULL << kind)
+
+/*
+ * Populate show->state.name with type name information.
+ * Format of type name is
+ *
+ * [.member_name = ] (type_name)
+ */
+static const char *btf_show_name(struct btf_show *show)
+{
+	/* BTF_MAX_ITER array suffixes "[]" */
+	const char *array_suffixes = "[][][][][][][][][][]";
+	const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
+	/* BTF_MAX_ITER pointer suffixes "*" */
+	const char *ptr_suffixes = "**********";
+	const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
+	const char *name = NULL, *prefix = "", *parens = "";
+	const struct btf_member *m = show->state.member;
+	const struct btf_type *t;
+	const struct btf_array *array;
+	u32 id = show->state.type_id;
+	const char *member = NULL;
+	bool show_member = false;
+	u64 kinds = 0;
+	int i;
+
+	show->state.name[0] = '\0';
+
+	/*
+	 * Don't show type name if we're showing an array member;
+	 * in that case we show the array type so don't need to repeat
+	 * ourselves for each member.
+	 */
+	if (show->state.array_member)
+		return "";
+
+	/* Retrieve member name, if any. */
+	if (m) {
+		member = btf_name_by_offset(show->btf, m->name_off);
+		show_member = strlen(member) > 0;
+		id = m->type;
+	}
+
+	/*
+	 * Start with type_id, as we have resolved the struct btf_type *
+	 * via btf_modifier_show() past the parent typedef to the child
+	 * struct, int etc it is defined as.  In such cases, the type_id
+	 * still represents the starting type while the struct btf_type *
+	 * in our show->state points at the resolved type of the typedef.
+	 */
+	t = btf_type_by_id(show->btf, id);
+	if (!t)
+		return "";
+
+	/*
+	 * The goal here is to build up the right number of pointer and
+	 * array suffixes while ensuring the type name for a typedef
+	 * is represented.  Along the way we accumulate a list of
+	 * BTF kinds we have encountered, since these will inform later
+	 * display; for example, pointer types will not require an
+	 * opening "{" for struct, we will just display the pointer value.
+	 *
+	 * We also want to accumulate the right number of pointer or array
+	 * indices in the format string while iterating until we get to
+	 * the typedef/pointee/array member target type.
+	 *
+	 * We start by pointing at the end of pointer and array suffix
+	 * strings; as we accumulate pointers and arrays we move the pointer
+	 * or array string backwards so it will show the expected number of
+	 * '*' or '[]' for the type.  BTF_SHOW_MAX_ITER of nesting of pointers
+	 * and/or arrays and typedefs are supported as a precaution.
+	 *
+	 * We also want to get typedef name while proceeding to resolve
+	 * type it points to so that we can add parentheses if it is a
+	 * "typedef struct" etc.
+	 */
+	for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
+
+		switch (BTF_INFO_KIND(t->info)) {
+		case BTF_KIND_TYPEDEF:
+			if (!name)
+				name = btf_name_by_offset(show->btf,
+							       t->name_off);
+			kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
+			id = t->type;
+			break;
+		case BTF_KIND_ARRAY:
+			kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
+			parens = "[";
+			if (!t)
+				return "";
+			array = btf_type_array(t);
+			if (array_suffix > array_suffixes)
+				array_suffix -= 2;
+			id = array->type;
+			break;
+		case BTF_KIND_PTR:
+			kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
+			if (ptr_suffix > ptr_suffixes)
+				ptr_suffix -= 1;
+			id = t->type;
+			break;
+		default:
+			id = 0;
+			break;
+		}
+		if (!id)
+			break;
+		t = btf_type_skip_qualifiers(show->btf, id);
+	}
+	/* We may not be able to represent this type; bail to be safe */
+	if (i == BTF_SHOW_MAX_ITER)
+		return "";
+
+	if (!name)
+		name = btf_name_by_offset(show->btf, t->name_off);
+
+	switch (BTF_INFO_KIND(t->info)) {
+	case BTF_KIND_STRUCT:
+	case BTF_KIND_UNION:
+		prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
+			 "struct" : "union";
+		/* if it's an array of struct/union, parens is already set */
+		if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
+			parens = "{";
+		break;
+	case BTF_KIND_ENUM:
+	case BTF_KIND_ENUM64:
+		prefix = "enum";
+		break;
+	default:
+		break;
+	}
+
+	/* pointer does not require parens */
+	if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
+		parens = "";
+	/* typedef does not require struct/union/enum prefix */
+	if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
+		prefix = "";
+
+	if (!name)
+		name = "";
+
+	/* Even if we don't want type name info, we want parentheses etc */
+	if (show->flags & BTF_SHOW_NONAME)
+		snprintf(show->state.name, sizeof(show->state.name), "%s",
+			 parens);
+	else
+		snprintf(show->state.name, sizeof(show->state.name),
+			 "%s%s%s(%s%s%s%s%s%s)%s",
+			 /* first 3 strings comprise ".member = " */
+			 show_member ? "." : "",
+			 show_member ? member : "",
+			 show_member ? " = " : "",
+			 /* ...next is our prefix (struct, enum, etc) */
+			 prefix,
+			 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
+			 /* ...this is the type name itself */
+			 name,
+			 /* ...suffixed by the appropriate '*', '[]' suffixes */
+			 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
+			 array_suffix, parens);
+
+	return show->state.name;
+}
+
+static const char *__btf_show_indent(struct btf_show *show)
+{
+	const char *indents = "                                ";
+	const char *indent = &indents[strlen(indents)];
+
+	if ((indent - show->state.depth) >= indents)
+		return indent - show->state.depth;
+	return indents;
+}
+
+static const char *btf_show_indent(struct btf_show *show)
+{
+	return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
+}
+
+static const char *btf_show_newline(struct btf_show *show)
+{
+	return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
+}
+
+static const char *btf_show_delim(struct btf_show *show)
+{
+	if (show->state.depth == 0)
+		return "";
+
+	if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
+		BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
+		return "|";
+
+	return ",";
+}
+
+__printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
+{
+	va_list args;
+
+	if (!show->state.depth_check) {
+		va_start(args, fmt);
+		show->showfn(show, fmt, args);
+		va_end(args);
+	}
+}
+
+/* Macros are used here as btf_show_type_value[s]() prepends and appends
+ * format specifiers to the format specifier passed in; these do the work of
+ * adding indentation, delimiters etc while the caller simply has to specify
+ * the type value(s) in the format specifier + value(s).
+ */
+#define btf_show_type_value(show, fmt, value)				       \
+	do {								       \
+		if ((value) != (__typeof__(value))0 ||			       \
+		    (show->flags & BTF_SHOW_ZERO) ||			       \
+		    show->state.depth == 0) {				       \
+			btf_show(show, "%s%s" fmt "%s%s",		       \
+				 btf_show_indent(show),			       \
+				 btf_show_name(show),			       \
+				 value, btf_show_delim(show),		       \
+				 btf_show_newline(show));		       \
+			if (show->state.depth > show->state.depth_to_show)     \
+				show->state.depth_to_show = show->state.depth; \
+		}							       \
+	} while (0)
+
+#define btf_show_type_values(show, fmt, ...)				       \
+	do {								       \
+		btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show),       \
+			 btf_show_name(show),				       \
+			 __VA_ARGS__, btf_show_delim(show),		       \
+			 btf_show_newline(show));			       \
+		if (show->state.depth > show->state.depth_to_show)	       \
+			show->state.depth_to_show = show->state.depth;	       \
+	} while (0)
+
+/* How much is left to copy to safe buffer after @data? */
+static int btf_show_obj_size_left(struct btf_show *show, void *data)
+{
+	return show->obj.head + show->obj.size - data;
+}
+
+/* Is object pointed to by @data of @size already copied to our safe buffer? */
+static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
+{
+	return data >= show->obj.data &&
+	       (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
+}
+
+/*
+ * If object pointed to by @data of @size falls within our safe buffer, return
+ * the equivalent pointer to the same safe data.  Assumes
+ * copy_from_kernel_nofault() has already happened and our safe buffer is
+ * populated.
+ */
+static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
+{
+	if (btf_show_obj_is_safe(show, data, size))
+		return show->obj.safe + (data - show->obj.data);
+	return NULL;
+}
+
+/*
+ * Return a safe-to-access version of data pointed to by @data.
+ * We do this by copying the relevant amount of information
+ * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
+ *
+ * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
+ * safe copy is needed.
+ *
+ * Otherwise we need to determine if we have the required amount
+ * of data (determined by the @data pointer and the size of the
+ * largest base type we can encounter (represented by
+ * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
+ * that we will be able to print some of the current object,
+ * and if more is needed a copy will be triggered.
+ * Some objects such as structs will not fit into the buffer;
+ * in such cases additional copies when we iterate over their
+ * members may be needed.
+ *
+ * btf_show_obj_safe() is used to return a safe buffer for
+ * btf_show_start_type(); this ensures that as we recurse into
+ * nested types we always have safe data for the given type.
+ * This approach is somewhat wasteful; it's possible for example
+ * that when iterating over a large union we'll end up copying the
+ * same data repeatedly, but the goal is safety not performance.
+ * We use stack data as opposed to per-CPU buffers because the
+ * iteration over a type can take some time, and preemption handling
+ * would greatly complicate use of the safe buffer.
+ */
+static void *btf_show_obj_safe(struct btf_show *show,
+			       const struct btf_type *t,
+			       void *data)
+{
+	const struct btf_type *rt;
+	int size_left, size;
+	void *safe = NULL;
+
+	if (show->flags & BTF_SHOW_UNSAFE)
+		return data;
+
+	rt = btf_resolve_size(show->btf, t, &size);
+	if (IS_ERR(rt)) {
+		show->state.status = PTR_ERR(rt);
+		return NULL;
+	}
+
+	/*
+	 * Is this toplevel object? If so, set total object size and
+	 * initialize pointers.  Otherwise check if we still fall within
+	 * our safe object data.
+	 */
+	if (show->state.depth == 0) {
+		show->obj.size = size;
+		show->obj.head = data;
+	} else {
+		/*
+		 * If the size of the current object is > our remaining
+		 * safe buffer we _may_ need to do a new copy.  However
+		 * consider the case of a nested struct; it's size pushes
+		 * us over the safe buffer limit, but showing any individual
+		 * struct members does not.  In such cases, we don't need
+		 * to initiate a fresh copy yet; however we definitely need
+		 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
+		 * in our buffer, regardless of the current object size.
+		 * The logic here is that as we resolve types we will
+		 * hit a base type at some point, and we need to be sure
+		 * the next chunk of data is safely available to display
+		 * that type info safely.  We cannot rely on the size of
+		 * the current object here because it may be much larger
+		 * than our current buffer (e.g. task_struct is 8k).
+		 * All we want to do here is ensure that we can print the
+		 * next basic type, which we can if either
+		 * - the current type size is within the safe buffer; or
+		 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
+		 *   the safe buffer.
+		 */
+		safe = __btf_show_obj_safe(show, data,
+					   min(size,
+					       BTF_SHOW_OBJ_BASE_TYPE_SIZE));
+	}
+
+	/*
+	 * We need a new copy to our safe object, either because we haven't
+	 * yet copied and are initializing safe data, or because the data
+	 * we want falls outside the boundaries of the safe object.
+	 */
+	if (!safe) {
+		size_left = btf_show_obj_size_left(show, data);
+		if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
+			size_left = BTF_SHOW_OBJ_SAFE_SIZE;
+		show->state.status = copy_from_kernel_nofault(show->obj.safe,
+							      data, size_left);
+		if (!show->state.status) {
+			show->obj.data = data;
+			safe = show->obj.safe;
+		}
+	}
+
+	return safe;
+}
+
+/*
+ * Set the type we are starting to show and return a safe data pointer
+ * to be used for showing the associated data.
+ */
+static void *btf_show_start_type(struct btf_show *show,
+				 const struct btf_type *t,
+				 u32 type_id, void *data)
+{
+	show->state.type = t;
+	show->state.type_id = type_id;
+	show->state.name[0] = '\0';
+
+	return btf_show_obj_safe(show, t, data);
+}
+
+static void btf_show_end_type(struct btf_show *show)
+{
+	show->state.type = NULL;
+	show->state.type_id = 0;
+	show->state.name[0] = '\0';
+}
+
+static void *btf_show_start_aggr_type(struct btf_show *show,
+				      const struct btf_type *t,
+				      u32 type_id, void *data)
+{
+	void *safe_data = btf_show_start_type(show, t, type_id, data);
+
+	if (!safe_data)
+		return safe_data;
+
+	btf_show(show, "%s%s%s", btf_show_indent(show),
+		 btf_show_name(show),
+		 btf_show_newline(show));
+	show->state.depth++;
+	return safe_data;
+}
+
+static void btf_show_end_aggr_type(struct btf_show *show,
+				   const char *suffix)
+{
+	show->state.depth--;
+	btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
+		 btf_show_delim(show), btf_show_newline(show));
+	btf_show_end_type(show);
+}
+
+static void btf_show_start_member(struct btf_show *show,
+				  const struct btf_member *m)
+{
+	show->state.member = m;
+}
+
+static void btf_show_start_array_member(struct btf_show *show)
+{
+	show->state.array_member = 1;
+	btf_show_start_member(show, NULL);
+}
+
+static void btf_show_end_member(struct btf_show *show)
+{
+	show->state.member = NULL;
+}
+
+static void btf_show_end_array_member(struct btf_show *show)
+{
+	show->state.array_member = 0;
+	btf_show_end_member(show);
+}
+
+static void *btf_show_start_array_type(struct btf_show *show,
+				       const struct btf_type *t,
+				       u32 type_id,
+				       u16 array_encoding,
+				       void *data)
+{
+	show->state.array_encoding = array_encoding;
+	show->state.array_terminated = 0;
+	return btf_show_start_aggr_type(show, t, type_id, data);
+}
+
+static void btf_show_end_array_type(struct btf_show *show)
+{
+	show->state.array_encoding = 0;
+	show->state.array_terminated = 0;
+	btf_show_end_aggr_type(show, "]");
+}
+
+static void *btf_show_start_struct_type(struct btf_show *show,
+					const struct btf_type *t,
+					u32 type_id,
+					void *data)
+{
+	return btf_show_start_aggr_type(show, t, type_id, data);
+}
+
+static void btf_show_end_struct_type(struct btf_show *show)
+{
+	btf_show_end_aggr_type(show, "}");
+}
+
+__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
+					      const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	bpf_verifier_vlog(log, fmt, args);
+	va_end(args);
+}
+
+__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
+					    const char *fmt, ...)
+{
+	struct bpf_verifier_log *log = &env->log;
+	va_list args;
+
+	if (!bpf_verifier_log_needed(log))
+		return;
+
+	va_start(args, fmt);
+	bpf_verifier_vlog(log, fmt, args);
+	va_end(args);
+}
+
+__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
+						   const struct btf_type *t,
+						   bool log_details,
+						   const char *fmt, ...)
+{
+	struct bpf_verifier_log *log = &env->log;
+	struct btf *btf = env->btf;
+	va_list args;
+
+	if (!bpf_verifier_log_needed(log))
+		return;
+
+	/* btf verifier prints all types it is processing via
+	 * btf_verifier_log_type(..., fmt = NULL).
+	 * Skip those prints for in-kernel BTF verification.
+	 */
+	if (log->level == BPF_LOG_KERNEL && !fmt)
+		return;
+
+	__btf_verifier_log(log, "[%u] %s %s%s",
+			   env->log_type_id,
+			   btf_type_str(t),
+			   __btf_name_by_offset(btf, t->name_off),
+			   log_details ? " " : "");
+
+	if (log_details)
+		btf_type_ops(t)->log_details(env, t);
+
+	if (fmt && *fmt) {
+		__btf_verifier_log(log, " ");
+		va_start(args, fmt);
+		bpf_verifier_vlog(log, fmt, args);
+		va_end(args);
+	}
+
+	__btf_verifier_log(log, "\n");
+}
+
+#define btf_verifier_log_type(env, t, ...) \
+	__btf_verifier_log_type((env), (t), true, __VA_ARGS__)
+#define btf_verifier_log_basic(env, t, ...) \
+	__btf_verifier_log_type((env), (t), false, __VA_ARGS__)
+
+__printf(4, 5)
+static void btf_verifier_log_member(struct btf_verifier_env *env,
+				    const struct btf_type *struct_type,
+				    const struct btf_member *member,
+				    const char *fmt, ...)
+{
+	struct bpf_verifier_log *log = &env->log;
+	struct btf *btf = env->btf;
+	va_list args;
+
+	if (!bpf_verifier_log_needed(log))
+		return;
+
+	if (log->level == BPF_LOG_KERNEL && !fmt)
+		return;
+	/* The CHECK_META phase already did a btf dump.
+	 *
+	 * If member is logged again, it must hit an error in
+	 * parsing this member.  It is useful to print out which
+	 * struct this member belongs to.
+	 */
+	if (env->phase != CHECK_META)
+		btf_verifier_log_type(env, struct_type, NULL);
+
+	if (btf_type_kflag(struct_type))
+		__btf_verifier_log(log,
+				   "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
+				   __btf_name_by_offset(btf, member->name_off),
+				   member->type,
+				   BTF_MEMBER_BITFIELD_SIZE(member->offset),
+				   BTF_MEMBER_BIT_OFFSET(member->offset));
+	else
+		__btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
+				   __btf_name_by_offset(btf, member->name_off),
+				   member->type, member->offset);
+
+	if (fmt && *fmt) {
+		__btf_verifier_log(log, " ");
+		va_start(args, fmt);
+		bpf_verifier_vlog(log, fmt, args);
+		va_end(args);
+	}
+
+	__btf_verifier_log(log, "\n");
+}
+
+__printf(4, 5)
+static void btf_verifier_log_vsi(struct btf_verifier_env *env,
+				 const struct btf_type *datasec_type,
+				 const struct btf_var_secinfo *vsi,
+				 const char *fmt, ...)
+{
+	struct bpf_verifier_log *log = &env->log;
+	va_list args;
+
+	if (!bpf_verifier_log_needed(log))
+		return;
+	if (log->level == BPF_LOG_KERNEL && !fmt)
+		return;
+	if (env->phase != CHECK_META)
+		btf_verifier_log_type(env, datasec_type, NULL);
+
+	__btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
+			   vsi->type, vsi->offset, vsi->size);
+	if (fmt && *fmt) {
+		__btf_verifier_log(log, " ");
+		va_start(args, fmt);
+		bpf_verifier_vlog(log, fmt, args);
+		va_end(args);
+	}
+
+	__btf_verifier_log(log, "\n");
+}
+
+static void btf_verifier_log_hdr(struct btf_verifier_env *env,
+				 u32 btf_data_size)
+{
+	struct bpf_verifier_log *log = &env->log;
+	const struct btf *btf = env->btf;
+	const struct btf_header *hdr;
+
+	if (!bpf_verifier_log_needed(log))
+		return;
+
+	if (log->level == BPF_LOG_KERNEL)
+		return;
+	hdr = &btf->hdr;
+	__btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
+	__btf_verifier_log(log, "version: %u\n", hdr->version);
+	__btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
+	__btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
+	__btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
+	__btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
+	__btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
+	__btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
+	__btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
+}
+
+static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
+{
+	struct btf *btf = env->btf;
+
+	if (btf->types_size == btf->nr_types) {
+		/* Expand 'types' array */
+
+		struct btf_type **new_types;
+		u32 expand_by, new_size;
+
+		if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
+			btf_verifier_log(env, "Exceeded max num of types");
+			return -E2BIG;
+		}
+
+		expand_by = max_t(u32, btf->types_size >> 2, 16);
+		new_size = min_t(u32, BTF_MAX_TYPE,
+				 btf->types_size + expand_by);
+
+		new_types = kvcalloc(new_size, sizeof(*new_types),
+				     GFP_KERNEL | __GFP_NOWARN);
+		if (!new_types)
+			return -ENOMEM;
+
+		if (btf->nr_types == 0) {
+			if (!btf->base_btf) {
+				/* lazily init VOID type */
+				new_types[0] = &btf_void;
+				btf->nr_types++;
+			}
+		} else {
+			memcpy(new_types, btf->types,
+			       sizeof(*btf->types) * btf->nr_types);
+		}
+
+		kvfree(btf->types);
+		btf->types = new_types;
+		btf->types_size = new_size;
+	}
+
+	btf->types[btf->nr_types++] = t;
+
+	return 0;
+}
+
+static int btf_alloc_id(struct btf *btf)
+{
+	int id;
+
+	idr_preload(GFP_KERNEL);
+	spin_lock_bh(&btf_idr_lock);
+	id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
+	if (id > 0)
+		btf->id = id;
+	spin_unlock_bh(&btf_idr_lock);
+	idr_preload_end();
+
+	if (WARN_ON_ONCE(!id))
+		return -ENOSPC;
+
+	return id > 0 ? 0 : id;
+}
+
+static void btf_free_id(struct btf *btf)
+{
+	unsigned long flags;
+
+	/*
+	 * In map-in-map, calling map_delete_elem() on outer
+	 * map will call bpf_map_put on the inner map.
+	 * It will then eventually call btf_free_id()
+	 * on the inner map.  Some of the map_delete_elem()
+	 * implementation may have irq disabled, so
+	 * we need to use the _irqsave() version instead
+	 * of the _bh() version.
+	 */
+	spin_lock_irqsave(&btf_idr_lock, flags);
+	idr_remove(&btf_idr, btf->id);
+	spin_unlock_irqrestore(&btf_idr_lock, flags);
+}
+
+static void btf_free_kfunc_set_tab(struct btf *btf)
+{
+	struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
+	int hook;
+
+	if (!tab)
+		return;
+	/* For module BTF, we directly assign the sets being registered, so
+	 * there is nothing to free except kfunc_set_tab.
+	 */
+	if (btf_is_module(btf))
+		goto free_tab;
+	for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++)
+		kfree(tab->sets[hook]);
+free_tab:
+	kfree(tab);
+	btf->kfunc_set_tab = NULL;
+}
+
+static void btf_free_dtor_kfunc_tab(struct btf *btf)
+{
+	struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
+
+	if (!tab)
+		return;
+	kfree(tab);
+	btf->dtor_kfunc_tab = NULL;
+}
+
+static void btf_free(struct btf *btf)
+{
+	btf_free_dtor_kfunc_tab(btf);
+	btf_free_kfunc_set_tab(btf);
+	kvfree(btf->types);
+	kvfree(btf->resolved_sizes);
+	kvfree(btf->resolved_ids);
+	kvfree(btf->data);
+	kfree(btf);
+}
+
+static void btf_free_rcu(struct rcu_head *rcu)
+{
+	struct btf *btf = container_of(rcu, struct btf, rcu);
+
+	btf_free(btf);
+}
+
+void btf_get(struct btf *btf)
+{
+	refcount_inc(&btf->refcnt);
+}
+
+void btf_put(struct btf *btf)
+{
+	if (btf && refcount_dec_and_test(&btf->refcnt)) {
+		btf_free_id(btf);
+		call_rcu(&btf->rcu, btf_free_rcu);
+	}
+}
+
+static int env_resolve_init(struct btf_verifier_env *env)
+{
+	struct btf *btf = env->btf;
+	u32 nr_types = btf->nr_types;
+	u32 *resolved_sizes = NULL;
+	u32 *resolved_ids = NULL;
+	u8 *visit_states = NULL;
+
+	resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
+				  GFP_KERNEL | __GFP_NOWARN);
+	if (!resolved_sizes)
+		goto nomem;
+
+	resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
+				GFP_KERNEL | __GFP_NOWARN);
+	if (!resolved_ids)
+		goto nomem;
+
+	visit_states = kvcalloc(nr_types, sizeof(*visit_states),
+				GFP_KERNEL | __GFP_NOWARN);
+	if (!visit_states)
+		goto nomem;
+
+	btf->resolved_sizes = resolved_sizes;
+	btf->resolved_ids = resolved_ids;
+	env->visit_states = visit_states;
+
+	return 0;
+
+nomem:
+	kvfree(resolved_sizes);
+	kvfree(resolved_ids);
+	kvfree(visit_states);
+	return -ENOMEM;
+}
+
+static void btf_verifier_env_free(struct btf_verifier_env *env)
+{
+	kvfree(env->visit_states);
+	kfree(env);
+}
+
+static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
+				     const struct btf_type *next_type)
+{
+	switch (env->resolve_mode) {
+	case RESOLVE_TBD:
+		/* int, enum or void is a sink */
+		return !btf_type_needs_resolve(next_type);
+	case RESOLVE_PTR:
+		/* int, enum, void, struct, array, func or func_proto is a sink
+		 * for ptr
+		 */
+		return !btf_type_is_modifier(next_type) &&
+			!btf_type_is_ptr(next_type);
+	case RESOLVE_STRUCT_OR_ARRAY:
+		/* int, enum, void, ptr, func or func_proto is a sink
+		 * for struct and array
+		 */
+		return !btf_type_is_modifier(next_type) &&
+			!btf_type_is_array(next_type) &&
+			!btf_type_is_struct(next_type);
+	default:
+		BUG();
+	}
+}
+
+static bool env_type_is_resolved(const struct btf_verifier_env *env,
+				 u32 type_id)
+{
+	/* base BTF types should be resolved by now */
+	if (type_id < env->btf->start_id)
+		return true;
+
+	return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
+}
+
+static int env_stack_push(struct btf_verifier_env *env,
+			  const struct btf_type *t, u32 type_id)
+{
+	const struct btf *btf = env->btf;
+	struct resolve_vertex *v;
+
+	if (env->top_stack == MAX_RESOLVE_DEPTH)
+		return -E2BIG;
+
+	if (type_id < btf->start_id
+	    || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
+		return -EEXIST;
+
+	env->visit_states[type_id - btf->start_id] = VISITED;
+
+	v = &env->stack[env->top_stack++];
+	v->t = t;
+	v->type_id = type_id;
+	v->next_member = 0;
+
+	if (env->resolve_mode == RESOLVE_TBD) {
+		if (btf_type_is_ptr(t))
+			env->resolve_mode = RESOLVE_PTR;
+		else if (btf_type_is_struct(t) || btf_type_is_array(t))
+			env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
+	}
+
+	return 0;
+}
+
+static void env_stack_set_next_member(struct btf_verifier_env *env,
+				      u16 next_member)
+{
+	env->stack[env->top_stack - 1].next_member = next_member;
+}
+
+static void env_stack_pop_resolved(struct btf_verifier_env *env,
+				   u32 resolved_type_id,
+				   u32 resolved_size)
+{
+	u32 type_id = env->stack[--(env->top_stack)].type_id;
+	struct btf *btf = env->btf;
+
+	type_id -= btf->start_id; /* adjust to local type id */
+	btf->resolved_sizes[type_id] = resolved_size;
+	btf->resolved_ids[type_id] = resolved_type_id;
+	env->visit_states[type_id] = RESOLVED;
+}
+
+static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
+{
+	return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
+}
+
+/* Resolve the size of a passed-in "type"
+ *
+ * type: is an array (e.g. u32 array[x][y])
+ * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
+ * *type_size: (x * y * sizeof(u32)).  Hence, *type_size always
+ *             corresponds to the return type.
+ * *elem_type: u32
+ * *elem_id: id of u32
+ * *total_nelems: (x * y).  Hence, individual elem size is
+ *                (*type_size / *total_nelems)
+ * *type_id: id of type if it's changed within the function, 0 if not
+ *
+ * type: is not an array (e.g. const struct X)
+ * return type: type "struct X"
+ * *type_size: sizeof(struct X)
+ * *elem_type: same as return type ("struct X")
+ * *elem_id: 0
+ * *total_nelems: 1
+ * *type_id: id of type if it's changed within the function, 0 if not
+ */
+static const struct btf_type *
+__btf_resolve_size(const struct btf *btf, const struct btf_type *type,
+		   u32 *type_size, const struct btf_type **elem_type,
+		   u32 *elem_id, u32 *total_nelems, u32 *type_id)
+{
+	const struct btf_type *array_type = NULL;
+	const struct btf_array *array = NULL;
+	u32 i, size, nelems = 1, id = 0;
+
+	for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
+		switch (BTF_INFO_KIND(type->info)) {
+		/* type->size can be used */
+		case BTF_KIND_INT:
+		case BTF_KIND_STRUCT:
+		case BTF_KIND_UNION:
+		case BTF_KIND_ENUM:
+		case BTF_KIND_FLOAT:
+		case BTF_KIND_ENUM64:
+			size = type->size;
+			goto resolved;
+
+		case BTF_KIND_PTR:
+			size = sizeof(void *);
+			goto resolved;
+
+		/* Modifiers */
+		case BTF_KIND_TYPEDEF:
+		case BTF_KIND_VOLATILE:
+		case BTF_KIND_CONST:
+		case BTF_KIND_RESTRICT:
+		case BTF_KIND_TYPE_TAG:
+			id = type->type;
+			type = btf_type_by_id(btf, type->type);
+			break;
+
+		case BTF_KIND_ARRAY:
+			if (!array_type)
+				array_type = type;
+			array = btf_type_array(type);
+			if (nelems && array->nelems > U32_MAX / nelems)
+				return ERR_PTR(-EINVAL);
+			nelems *= array->nelems;
+			type = btf_type_by_id(btf, array->type);
+			break;
+
+		/* type without size */
+		default:
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
+	return ERR_PTR(-EINVAL);
+
+resolved:
+	if (nelems && size > U32_MAX / nelems)
+		return ERR_PTR(-EINVAL);
+
+	*type_size = nelems * size;
+	if (total_nelems)
+		*total_nelems = nelems;
+	if (elem_type)
+		*elem_type = type;
+	if (elem_id)
+		*elem_id = array ? array->type : 0;
+	if (type_id && id)
+		*type_id = id;
+
+	return array_type ? : type;
+}
+
+const struct btf_type *
+btf_resolve_size(const struct btf *btf, const struct btf_type *type,
+		 u32 *type_size)
+{
+	return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
+}
+
+static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
+{
+	while (type_id < btf->start_id)
+		btf = btf->base_btf;
+
+	return btf->resolved_ids[type_id - btf->start_id];
+}
+
+/* The input param "type_id" must point to a needs_resolve type */
+static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
+						  u32 *type_id)
+{
+	*type_id = btf_resolved_type_id(btf, *type_id);
+	return btf_type_by_id(btf, *type_id);
+}
+
+static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
+{
+	while (type_id < btf->start_id)
+		btf = btf->base_btf;
+
+	return btf->resolved_sizes[type_id - btf->start_id];
+}
+
+const struct btf_type *btf_type_id_size(const struct btf *btf,
+					u32 *type_id, u32 *ret_size)
+{
+	const struct btf_type *size_type;
+	u32 size_type_id = *type_id;
+	u32 size = 0;
+
+	size_type = btf_type_by_id(btf, size_type_id);
+	if (btf_type_nosize_or_null(size_type))
+		return NULL;
+
+	if (btf_type_has_size(size_type)) {
+		size = size_type->size;
+	} else if (btf_type_is_array(size_type)) {
+		size = btf_resolved_type_size(btf, size_type_id);
+	} else if (btf_type_is_ptr(size_type)) {
+		size = sizeof(void *);
+	} else {
+		if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
+				 !btf_type_is_var(size_type)))
+			return NULL;
+
+		size_type_id = btf_resolved_type_id(btf, size_type_id);
+		size_type = btf_type_by_id(btf, size_type_id);
+		if (btf_type_nosize_or_null(size_type))
+			return NULL;
+		else if (btf_type_has_size(size_type))
+			size = size_type->size;
+		else if (btf_type_is_array(size_type))
+			size = btf_resolved_type_size(btf, size_type_id);
+		else if (btf_type_is_ptr(size_type))
+			size = sizeof(void *);
+		else
+			return NULL;
+	}
+
+	*type_id = size_type_id;
+	if (ret_size)
+		*ret_size = size;
+
+	return size_type;
+}
+
+static int btf_df_check_member(struct btf_verifier_env *env,
+			       const struct btf_type *struct_type,
+			       const struct btf_member *member,
+			       const struct btf_type *member_type)
+{
+	btf_verifier_log_basic(env, struct_type,
+			       "Unsupported check_member");
+	return -EINVAL;
+}
+
+static int btf_df_check_kflag_member(struct btf_verifier_env *env,
+				     const struct btf_type *struct_type,
+				     const struct btf_member *member,
+				     const struct btf_type *member_type)
+{
+	btf_verifier_log_basic(env, struct_type,
+			       "Unsupported check_kflag_member");
+	return -EINVAL;
+}
+
+/* Used for ptr, array struct/union and float type members.
+ * int, enum and modifier types have their specific callback functions.
+ */
+static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
+					  const struct btf_type *struct_type,
+					  const struct btf_member *member,
+					  const struct btf_type *member_type)
+{
+	if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Invalid member bitfield_size");
+		return -EINVAL;
+	}
+
+	/* bitfield size is 0, so member->offset represents bit offset only.
+	 * It is safe to call non kflag check_member variants.
+	 */
+	return btf_type_ops(member_type)->check_member(env, struct_type,
+						       member,
+						       member_type);
+}
+
+static int btf_df_resolve(struct btf_verifier_env *env,
+			  const struct resolve_vertex *v)
+{
+	btf_verifier_log_basic(env, v->t, "Unsupported resolve");
+	return -EINVAL;
+}
+
+static void btf_df_show(const struct btf *btf, const struct btf_type *t,
+			u32 type_id, void *data, u8 bits_offsets,
+			struct btf_show *show)
+{
+	btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
+}
+
+static int btf_int_check_member(struct btf_verifier_env *env,
+				const struct btf_type *struct_type,
+				const struct btf_member *member,
+				const struct btf_type *member_type)
+{
+	u32 int_data = btf_type_int(member_type);
+	u32 struct_bits_off = member->offset;
+	u32 struct_size = struct_type->size;
+	u32 nr_copy_bits;
+	u32 bytes_offset;
+
+	if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
+		btf_verifier_log_member(env, struct_type, member,
+					"bits_offset exceeds U32_MAX");
+		return -EINVAL;
+	}
+
+	struct_bits_off += BTF_INT_OFFSET(int_data);
+	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
+	nr_copy_bits = BTF_INT_BITS(int_data) +
+		BITS_PER_BYTE_MASKED(struct_bits_off);
+
+	if (nr_copy_bits > BITS_PER_U128) {
+		btf_verifier_log_member(env, struct_type, member,
+					"nr_copy_bits exceeds 128");
+		return -EINVAL;
+	}
+
+	if (struct_size < bytes_offset ||
+	    struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member exceeds struct_size");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int btf_int_check_kflag_member(struct btf_verifier_env *env,
+				      const struct btf_type *struct_type,
+				      const struct btf_member *member,
+				      const struct btf_type *member_type)
+{
+	u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
+	u32 int_data = btf_type_int(member_type);
+	u32 struct_size = struct_type->size;
+	u32 nr_copy_bits;
+
+	/* a regular int type is required for the kflag int member */
+	if (!btf_type_int_is_regular(member_type)) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Invalid member base type");
+		return -EINVAL;
+	}
+
+	/* check sanity of bitfield size */
+	nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
+	struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
+	nr_int_data_bits = BTF_INT_BITS(int_data);
+	if (!nr_bits) {
+		/* Not a bitfield member, member offset must be at byte
+		 * boundary.
+		 */
+		if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
+			btf_verifier_log_member(env, struct_type, member,
+						"Invalid member offset");
+			return -EINVAL;
+		}
+
+		nr_bits = nr_int_data_bits;
+	} else if (nr_bits > nr_int_data_bits) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Invalid member bitfield_size");
+		return -EINVAL;
+	}
+
+	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
+	nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
+	if (nr_copy_bits > BITS_PER_U128) {
+		btf_verifier_log_member(env, struct_type, member,
+					"nr_copy_bits exceeds 128");
+		return -EINVAL;
+	}
+
+	if (struct_size < bytes_offset ||
+	    struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member exceeds struct_size");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static s32 btf_int_check_meta(struct btf_verifier_env *env,
+			      const struct btf_type *t,
+			      u32 meta_left)
+{
+	u32 int_data, nr_bits, meta_needed = sizeof(int_data);
+	u16 encoding;
+
+	if (meta_left < meta_needed) {
+		btf_verifier_log_basic(env, t,
+				       "meta_left:%u meta_needed:%u",
+				       meta_left, meta_needed);
+		return -EINVAL;
+	}
+
+	if (btf_type_vlen(t)) {
+		btf_verifier_log_type(env, t, "vlen != 0");
+		return -EINVAL;
+	}
+
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
+	int_data = btf_type_int(t);
+	if (int_data & ~BTF_INT_MASK) {
+		btf_verifier_log_basic(env, t, "Invalid int_data:%x",
+				       int_data);
+		return -EINVAL;
+	}
+
+	nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
+
+	if (nr_bits > BITS_PER_U128) {
+		btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
+				      BITS_PER_U128);
+		return -EINVAL;
+	}
+
+	if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
+		btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
+		return -EINVAL;
+	}
+
+	/*
+	 * Only one of the encoding bits is allowed and it
+	 * should be sufficient for the pretty print purpose (i.e. decoding).
+	 * Multiple bits can be allowed later if it is found
+	 * to be insufficient.
+	 */
+	encoding = BTF_INT_ENCODING(int_data);
+	if (encoding &&
+	    encoding != BTF_INT_SIGNED &&
+	    encoding != BTF_INT_CHAR &&
+	    encoding != BTF_INT_BOOL) {
+		btf_verifier_log_type(env, t, "Unsupported encoding");
+		return -ENOTSUPP;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	return meta_needed;
+}
+
+static void btf_int_log(struct btf_verifier_env *env,
+			const struct btf_type *t)
+{
+	int int_data = btf_type_int(t);
+
+	btf_verifier_log(env,
+			 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
+			 t->size, BTF_INT_OFFSET(int_data),
+			 BTF_INT_BITS(int_data),
+			 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
+}
+
+static void btf_int128_print(struct btf_show *show, void *data)
+{
+	/* data points to a __int128 number.
+	 * Suppose
+	 *     int128_num = *(__int128 *)data;
+	 * The below formulas shows what upper_num and lower_num represents:
+	 *     upper_num = int128_num >> 64;
+	 *     lower_num = int128_num & 0xffffffffFFFFFFFFULL;
+	 */
+	u64 upper_num, lower_num;
+
+#ifdef __BIG_ENDIAN_BITFIELD
+	upper_num = *(u64 *)data;
+	lower_num = *(u64 *)(data + 8);
+#else
+	upper_num = *(u64 *)(data + 8);
+	lower_num = *(u64 *)data;
+#endif
+	if (upper_num == 0)
+		btf_show_type_value(show, "0x%llx", lower_num);
+	else
+		btf_show_type_values(show, "0x%llx%016llx", upper_num,
+				     lower_num);
+}
+
+static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
+			     u16 right_shift_bits)
+{
+	u64 upper_num, lower_num;
+
+#ifdef __BIG_ENDIAN_BITFIELD
+	upper_num = print_num[0];
+	lower_num = print_num[1];
+#else
+	upper_num = print_num[1];
+	lower_num = print_num[0];
+#endif
+
+	/* shake out un-needed bits by shift/or operations */
+	if (left_shift_bits >= 64) {
+		upper_num = lower_num << (left_shift_bits - 64);
+		lower_num = 0;
+	} else {
+		upper_num = (upper_num << left_shift_bits) |
+			    (lower_num >> (64 - left_shift_bits));
+		lower_num = lower_num << left_shift_bits;
+	}
+
+	if (right_shift_bits >= 64) {
+		lower_num = upper_num >> (right_shift_bits - 64);
+		upper_num = 0;
+	} else {
+		lower_num = (lower_num >> right_shift_bits) |
+			    (upper_num << (64 - right_shift_bits));
+		upper_num = upper_num >> right_shift_bits;
+	}
+
+#ifdef __BIG_ENDIAN_BITFIELD
+	print_num[0] = upper_num;
+	print_num[1] = lower_num;
+#else
+	print_num[0] = lower_num;
+	print_num[1] = upper_num;
+#endif
+}
+
+static void btf_bitfield_show(void *data, u8 bits_offset,
+			      u8 nr_bits, struct btf_show *show)
+{
+	u16 left_shift_bits, right_shift_bits;
+	u8 nr_copy_bytes;
+	u8 nr_copy_bits;
+	u64 print_num[2] = {};
+
+	nr_copy_bits = nr_bits + bits_offset;
+	nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
+
+	memcpy(print_num, data, nr_copy_bytes);
+
+#ifdef __BIG_ENDIAN_BITFIELD
+	left_shift_bits = bits_offset;
+#else
+	left_shift_bits = BITS_PER_U128 - nr_copy_bits;
+#endif
+	right_shift_bits = BITS_PER_U128 - nr_bits;
+
+	btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
+	btf_int128_print(show, print_num);
+}
+
+
+static void btf_int_bits_show(const struct btf *btf,
+			      const struct btf_type *t,
+			      void *data, u8 bits_offset,
+			      struct btf_show *show)
+{
+	u32 int_data = btf_type_int(t);
+	u8 nr_bits = BTF_INT_BITS(int_data);
+	u8 total_bits_offset;
+
+	/*
+	 * bits_offset is at most 7.
+	 * BTF_INT_OFFSET() cannot exceed 128 bits.
+	 */
+	total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
+	data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
+	bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
+	btf_bitfield_show(data, bits_offset, nr_bits, show);
+}
+
+static void btf_int_show(const struct btf *btf, const struct btf_type *t,
+			 u32 type_id, void *data, u8 bits_offset,
+			 struct btf_show *show)
+{
+	u32 int_data = btf_type_int(t);
+	u8 encoding = BTF_INT_ENCODING(int_data);
+	bool sign = encoding & BTF_INT_SIGNED;
+	u8 nr_bits = BTF_INT_BITS(int_data);
+	void *safe_data;
+
+	safe_data = btf_show_start_type(show, t, type_id, data);
+	if (!safe_data)
+		return;
+
+	if (bits_offset || BTF_INT_OFFSET(int_data) ||
+	    BITS_PER_BYTE_MASKED(nr_bits)) {
+		btf_int_bits_show(btf, t, safe_data, bits_offset, show);
+		goto out;
+	}
+
+	switch (nr_bits) {
+	case 128:
+		btf_int128_print(show, safe_data);
+		break;
+	case 64:
+		if (sign)
+			btf_show_type_value(show, "%lld", *(s64 *)safe_data);
+		else
+			btf_show_type_value(show, "%llu", *(u64 *)safe_data);
+		break;
+	case 32:
+		if (sign)
+			btf_show_type_value(show, "%d", *(s32 *)safe_data);
+		else
+			btf_show_type_value(show, "%u", *(u32 *)safe_data);
+		break;
+	case 16:
+		if (sign)
+			btf_show_type_value(show, "%d", *(s16 *)safe_data);
+		else
+			btf_show_type_value(show, "%u", *(u16 *)safe_data);
+		break;
+	case 8:
+		if (show->state.array_encoding == BTF_INT_CHAR) {
+			/* check for null terminator */
+			if (show->state.array_terminated)
+				break;
+			if (*(char *)data == '\0') {
+				show->state.array_terminated = 1;
+				break;
+			}
+			if (isprint(*(char *)data)) {
+				btf_show_type_value(show, "'%c'",
+						    *(char *)safe_data);
+				break;
+			}
+		}
+		if (sign)
+			btf_show_type_value(show, "%d", *(s8 *)safe_data);
+		else
+			btf_show_type_value(show, "%u", *(u8 *)safe_data);
+		break;
+	default:
+		btf_int_bits_show(btf, t, safe_data, bits_offset, show);
+		break;
+	}
+out:
+	btf_show_end_type(show);
+}
+
+static const struct btf_kind_operations int_ops = {
+	.check_meta = btf_int_check_meta,
+	.resolve = btf_df_resolve,
+	.check_member = btf_int_check_member,
+	.check_kflag_member = btf_int_check_kflag_member,
+	.log_details = btf_int_log,
+	.show = btf_int_show,
+};
+
+static int btf_modifier_check_member(struct btf_verifier_env *env,
+				     const struct btf_type *struct_type,
+				     const struct btf_member *member,
+				     const struct btf_type *member_type)
+{
+	const struct btf_type *resolved_type;
+	u32 resolved_type_id = member->type;
+	struct btf_member resolved_member;
+	struct btf *btf = env->btf;
+
+	resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
+	if (!resolved_type) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Invalid member");
+		return -EINVAL;
+	}
+
+	resolved_member = *member;
+	resolved_member.type = resolved_type_id;
+
+	return btf_type_ops(resolved_type)->check_member(env, struct_type,
+							 &resolved_member,
+							 resolved_type);
+}
+
+static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
+					   const struct btf_type *struct_type,
+					   const struct btf_member *member,
+					   const struct btf_type *member_type)
+{
+	const struct btf_type *resolved_type;
+	u32 resolved_type_id = member->type;
+	struct btf_member resolved_member;
+	struct btf *btf = env->btf;
+
+	resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
+	if (!resolved_type) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Invalid member");
+		return -EINVAL;
+	}
+
+	resolved_member = *member;
+	resolved_member.type = resolved_type_id;
+
+	return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
+							       &resolved_member,
+							       resolved_type);
+}
+
+static int btf_ptr_check_member(struct btf_verifier_env *env,
+				const struct btf_type *struct_type,
+				const struct btf_member *member,
+				const struct btf_type *member_type)
+{
+	u32 struct_size, struct_bits_off, bytes_offset;
+
+	struct_size = struct_type->size;
+	struct_bits_off = member->offset;
+	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
+
+	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member is not byte aligned");
+		return -EINVAL;
+	}
+
+	if (struct_size - bytes_offset < sizeof(void *)) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member exceeds struct_size");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int btf_ref_type_check_meta(struct btf_verifier_env *env,
+				   const struct btf_type *t,
+				   u32 meta_left)
+{
+	const char *value;
+
+	if (btf_type_vlen(t)) {
+		btf_verifier_log_type(env, t, "vlen != 0");
+		return -EINVAL;
+	}
+
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
+	if (!BTF_TYPE_ID_VALID(t->type)) {
+		btf_verifier_log_type(env, t, "Invalid type_id");
+		return -EINVAL;
+	}
+
+	/* typedef/type_tag type must have a valid name, and other ref types,
+	 * volatile, const, restrict, should have a null name.
+	 */
+	if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
+		if (!t->name_off ||
+		    !btf_name_valid_identifier(env->btf, t->name_off)) {
+			btf_verifier_log_type(env, t, "Invalid name");
+			return -EINVAL;
+		}
+	} else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
+		value = btf_name_by_offset(env->btf, t->name_off);
+		if (!value || !value[0]) {
+			btf_verifier_log_type(env, t, "Invalid name");
+			return -EINVAL;
+		}
+	} else {
+		if (t->name_off) {
+			btf_verifier_log_type(env, t, "Invalid name");
+			return -EINVAL;
+		}
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	return 0;
+}
+
+static int btf_modifier_resolve(struct btf_verifier_env *env,
+				const struct resolve_vertex *v)
+{
+	const struct btf_type *t = v->t;
+	const struct btf_type *next_type;
+	u32 next_type_id = t->type;
+	struct btf *btf = env->btf;
+
+	next_type = btf_type_by_id(btf, next_type_id);
+	if (!next_type || btf_type_is_resolve_source_only(next_type)) {
+		btf_verifier_log_type(env, v->t, "Invalid type_id");
+		return -EINVAL;
+	}
+
+	if (!env_type_is_resolve_sink(env, next_type) &&
+	    !env_type_is_resolved(env, next_type_id))
+		return env_stack_push(env, next_type, next_type_id);
+
+	/* Figure out the resolved next_type_id with size.
+	 * They will be stored in the current modifier's
+	 * resolved_ids and resolved_sizes such that it can
+	 * save us a few type-following when we use it later (e.g. in
+	 * pretty print).
+	 */
+	if (!btf_type_id_size(btf, &next_type_id, NULL)) {
+		if (env_type_is_resolved(env, next_type_id))
+			next_type = btf_type_id_resolve(btf, &next_type_id);
+
+		/* "typedef void new_void", "const void"...etc */
+		if (!btf_type_is_void(next_type) &&
+		    !btf_type_is_fwd(next_type) &&
+		    !btf_type_is_func_proto(next_type)) {
+			btf_verifier_log_type(env, v->t, "Invalid type_id");
+			return -EINVAL;
+		}
+	}
+
+	env_stack_pop_resolved(env, next_type_id, 0);
+
+	return 0;
+}
+
+static int btf_var_resolve(struct btf_verifier_env *env,
+			   const struct resolve_vertex *v)
+{
+	const struct btf_type *next_type;
+	const struct btf_type *t = v->t;
+	u32 next_type_id = t->type;
+	struct btf *btf = env->btf;
+
+	next_type = btf_type_by_id(btf, next_type_id);
+	if (!next_type || btf_type_is_resolve_source_only(next_type)) {
+		btf_verifier_log_type(env, v->t, "Invalid type_id");
+		return -EINVAL;
+	}
+
+	if (!env_type_is_resolve_sink(env, next_type) &&
+	    !env_type_is_resolved(env, next_type_id))
+		return env_stack_push(env, next_type, next_type_id);
+
+	if (btf_type_is_modifier(next_type)) {
+		const struct btf_type *resolved_type;
+		u32 resolved_type_id;
+
+		resolved_type_id = next_type_id;
+		resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
+
+		if (btf_type_is_ptr(resolved_type) &&
+		    !env_type_is_resolve_sink(env, resolved_type) &&
+		    !env_type_is_resolved(env, resolved_type_id))
+			return env_stack_push(env, resolved_type,
+					      resolved_type_id);
+	}
+
+	/* We must resolve to something concrete at this point, no
+	 * forward types or similar that would resolve to size of
+	 * zero is allowed.
+	 */
+	if (!btf_type_id_size(btf, &next_type_id, NULL)) {
+		btf_verifier_log_type(env, v->t, "Invalid type_id");
+		return -EINVAL;
+	}
+
+	env_stack_pop_resolved(env, next_type_id, 0);
+
+	return 0;
+}
+
+static int btf_ptr_resolve(struct btf_verifier_env *env,
+			   const struct resolve_vertex *v)
+{
+	const struct btf_type *next_type;
+	const struct btf_type *t = v->t;
+	u32 next_type_id = t->type;
+	struct btf *btf = env->btf;
+
+	next_type = btf_type_by_id(btf, next_type_id);
+	if (!next_type || btf_type_is_resolve_source_only(next_type)) {
+		btf_verifier_log_type(env, v->t, "Invalid type_id");
+		return -EINVAL;
+	}
+
+	if (!env_type_is_resolve_sink(env, next_type) &&
+	    !env_type_is_resolved(env, next_type_id))
+		return env_stack_push(env, next_type, next_type_id);
+
+	/* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
+	 * the modifier may have stopped resolving when it was resolved
+	 * to a ptr (last-resolved-ptr).
+	 *
+	 * We now need to continue from the last-resolved-ptr to
+	 * ensure the last-resolved-ptr will not referring back to
+	 * the current ptr (t).
+	 */
+	if (btf_type_is_modifier(next_type)) {
+		const struct btf_type *resolved_type;
+		u32 resolved_type_id;
+
+		resolved_type_id = next_type_id;
+		resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
+
+		if (btf_type_is_ptr(resolved_type) &&
+		    !env_type_is_resolve_sink(env, resolved_type) &&
+		    !env_type_is_resolved(env, resolved_type_id))
+			return env_stack_push(env, resolved_type,
+					      resolved_type_id);
+	}
+
+	if (!btf_type_id_size(btf, &next_type_id, NULL)) {
+		if (env_type_is_resolved(env, next_type_id))
+			next_type = btf_type_id_resolve(btf, &next_type_id);
+
+		if (!btf_type_is_void(next_type) &&
+		    !btf_type_is_fwd(next_type) &&
+		    !btf_type_is_func_proto(next_type)) {
+			btf_verifier_log_type(env, v->t, "Invalid type_id");
+			return -EINVAL;
+		}
+	}
+
+	env_stack_pop_resolved(env, next_type_id, 0);
+
+	return 0;
+}
+
+static void btf_modifier_show(const struct btf *btf,
+			      const struct btf_type *t,
+			      u32 type_id, void *data,
+			      u8 bits_offset, struct btf_show *show)
+{
+	if (btf->resolved_ids)
+		t = btf_type_id_resolve(btf, &type_id);
+	else
+		t = btf_type_skip_modifiers(btf, type_id, NULL);
+
+	btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
+}
+
+static void btf_var_show(const struct btf *btf, const struct btf_type *t,
+			 u32 type_id, void *data, u8 bits_offset,
+			 struct btf_show *show)
+{
+	t = btf_type_id_resolve(btf, &type_id);
+
+	btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
+}
+
+static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
+			 u32 type_id, void *data, u8 bits_offset,
+			 struct btf_show *show)
+{
+	void *safe_data;
+
+	safe_data = btf_show_start_type(show, t, type_id, data);
+	if (!safe_data)
+		return;
+
+	/* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
+	if (show->flags & BTF_SHOW_PTR_RAW)
+		btf_show_type_value(show, "0x%px", *(void **)safe_data);
+	else
+		btf_show_type_value(show, "0x%p", *(void **)safe_data);
+	btf_show_end_type(show);
+}
+
+static void btf_ref_type_log(struct btf_verifier_env *env,
+			     const struct btf_type *t)
+{
+	btf_verifier_log(env, "type_id=%u", t->type);
+}
+
+static struct btf_kind_operations modifier_ops = {
+	.check_meta = btf_ref_type_check_meta,
+	.resolve = btf_modifier_resolve,
+	.check_member = btf_modifier_check_member,
+	.check_kflag_member = btf_modifier_check_kflag_member,
+	.log_details = btf_ref_type_log,
+	.show = btf_modifier_show,
+};
+
+static struct btf_kind_operations ptr_ops = {
+	.check_meta = btf_ref_type_check_meta,
+	.resolve = btf_ptr_resolve,
+	.check_member = btf_ptr_check_member,
+	.check_kflag_member = btf_generic_check_kflag_member,
+	.log_details = btf_ref_type_log,
+	.show = btf_ptr_show,
+};
+
+static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
+			      const struct btf_type *t,
+			      u32 meta_left)
+{
+	if (btf_type_vlen(t)) {
+		btf_verifier_log_type(env, t, "vlen != 0");
+		return -EINVAL;
+	}
+
+	if (t->type) {
+		btf_verifier_log_type(env, t, "type != 0");
+		return -EINVAL;
+	}
+
+	/* fwd type must have a valid name */
+	if (!t->name_off ||
+	    !btf_name_valid_identifier(env->btf, t->name_off)) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	return 0;
+}
+
+static void btf_fwd_type_log(struct btf_verifier_env *env,
+			     const struct btf_type *t)
+{
+	btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
+}
+
+static struct btf_kind_operations fwd_ops = {
+	.check_meta = btf_fwd_check_meta,
+	.resolve = btf_df_resolve,
+	.check_member = btf_df_check_member,
+	.check_kflag_member = btf_df_check_kflag_member,
+	.log_details = btf_fwd_type_log,
+	.show = btf_df_show,
+};
+
+static int btf_array_check_member(struct btf_verifier_env *env,
+				  const struct btf_type *struct_type,
+				  const struct btf_member *member,
+				  const struct btf_type *member_type)
+{
+	u32 struct_bits_off = member->offset;
+	u32 struct_size, bytes_offset;
+	u32 array_type_id, array_size;
+	struct btf *btf = env->btf;
+
+	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member is not byte aligned");
+		return -EINVAL;
+	}
+
+	array_type_id = member->type;
+	btf_type_id_size(btf, &array_type_id, &array_size);
+	struct_size = struct_type->size;
+	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
+	if (struct_size - bytes_offset < array_size) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member exceeds struct_size");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static s32 btf_array_check_meta(struct btf_verifier_env *env,
+				const struct btf_type *t,
+				u32 meta_left)
+{
+	const struct btf_array *array = btf_type_array(t);
+	u32 meta_needed = sizeof(*array);
+
+	if (meta_left < meta_needed) {
+		btf_verifier_log_basic(env, t,
+				       "meta_left:%u meta_needed:%u",
+				       meta_left, meta_needed);
+		return -EINVAL;
+	}
+
+	/* array type should not have a name */
+	if (t->name_off) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
+	if (btf_type_vlen(t)) {
+		btf_verifier_log_type(env, t, "vlen != 0");
+		return -EINVAL;
+	}
+
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
+	if (t->size) {
+		btf_verifier_log_type(env, t, "size != 0");
+		return -EINVAL;
+	}
+
+	/* Array elem type and index type cannot be in type void,
+	 * so !array->type and !array->index_type are not allowed.
+	 */
+	if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
+		btf_verifier_log_type(env, t, "Invalid elem");
+		return -EINVAL;
+	}
+
+	if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
+		btf_verifier_log_type(env, t, "Invalid index");
+		return -EINVAL;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	return meta_needed;
+}
+
+static int btf_array_resolve(struct btf_verifier_env *env,
+			     const struct resolve_vertex *v)
+{
+	const struct btf_array *array = btf_type_array(v->t);
+	const struct btf_type *elem_type, *index_type;
+	u32 elem_type_id, index_type_id;
+	struct btf *btf = env->btf;
+	u32 elem_size;
+
+	/* Check array->index_type */
+	index_type_id = array->index_type;
+	index_type = btf_type_by_id(btf, index_type_id);
+	if (btf_type_nosize_or_null(index_type) ||
+	    btf_type_is_resolve_source_only(index_type)) {
+		btf_verifier_log_type(env, v->t, "Invalid index");
+		return -EINVAL;
+	}
+
+	if (!env_type_is_resolve_sink(env, index_type) &&
+	    !env_type_is_resolved(env, index_type_id))
+		return env_stack_push(env, index_type, index_type_id);
+
+	index_type = btf_type_id_size(btf, &index_type_id, NULL);
+	if (!index_type || !btf_type_is_int(index_type) ||
+	    !btf_type_int_is_regular(index_type)) {
+		btf_verifier_log_type(env, v->t, "Invalid index");
+		return -EINVAL;
+	}
+
+	/* Check array->type */
+	elem_type_id = array->type;
+	elem_type = btf_type_by_id(btf, elem_type_id);
+	if (btf_type_nosize_or_null(elem_type) ||
+	    btf_type_is_resolve_source_only(elem_type)) {
+		btf_verifier_log_type(env, v->t,
+				      "Invalid elem");
+		return -EINVAL;
+	}
+
+	if (!env_type_is_resolve_sink(env, elem_type) &&
+	    !env_type_is_resolved(env, elem_type_id))
+		return env_stack_push(env, elem_type, elem_type_id);
+
+	elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
+	if (!elem_type) {
+		btf_verifier_log_type(env, v->t, "Invalid elem");
+		return -EINVAL;
+	}
+
+	if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
+		btf_verifier_log_type(env, v->t, "Invalid array of int");
+		return -EINVAL;
+	}
+
+	if (array->nelems && elem_size > U32_MAX / array->nelems) {
+		btf_verifier_log_type(env, v->t,
+				      "Array size overflows U32_MAX");
+		return -EINVAL;
+	}
+
+	env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
+
+	return 0;
+}
+
+static void btf_array_log(struct btf_verifier_env *env,
+			  const struct btf_type *t)
+{
+	const struct btf_array *array = btf_type_array(t);
+
+	btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
+			 array->type, array->index_type, array->nelems);
+}
+
+static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
+			     u32 type_id, void *data, u8 bits_offset,
+			     struct btf_show *show)
+{
+	const struct btf_array *array = btf_type_array(t);
+	const struct btf_kind_operations *elem_ops;
+	const struct btf_type *elem_type;
+	u32 i, elem_size = 0, elem_type_id;
+	u16 encoding = 0;
+
+	elem_type_id = array->type;
+	elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
+	if (elem_type && btf_type_has_size(elem_type))
+		elem_size = elem_type->size;
+
+	if (elem_type && btf_type_is_int(elem_type)) {
+		u32 int_type = btf_type_int(elem_type);
+
+		encoding = BTF_INT_ENCODING(int_type);
+
+		/*
+		 * BTF_INT_CHAR encoding never seems to be set for
+		 * char arrays, so if size is 1 and element is
+		 * printable as a char, we'll do that.
+		 */
+		if (elem_size == 1)
+			encoding = BTF_INT_CHAR;
+	}
+
+	if (!btf_show_start_array_type(show, t, type_id, encoding, data))
+		return;
+
+	if (!elem_type)
+		goto out;
+	elem_ops = btf_type_ops(elem_type);
+
+	for (i = 0; i < array->nelems; i++) {
+
+		btf_show_start_array_member(show);
+
+		elem_ops->show(btf, elem_type, elem_type_id, data,
+			       bits_offset, show);
+		data += elem_size;
+
+		btf_show_end_array_member(show);
+
+		if (show->state.array_terminated)
+			break;
+	}
+out:
+	btf_show_end_array_type(show);
+}
+
+static void btf_array_show(const struct btf *btf, const struct btf_type *t,
+			   u32 type_id, void *data, u8 bits_offset,
+			   struct btf_show *show)
+{
+	const struct btf_member *m = show->state.member;
+
+	/*
+	 * First check if any members would be shown (are non-zero).
+	 * See comments above "struct btf_show" definition for more
+	 * details on how this works at a high-level.
+	 */
+	if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
+		if (!show->state.depth_check) {
+			show->state.depth_check = show->state.depth + 1;
+			show->state.depth_to_show = 0;
+		}
+		__btf_array_show(btf, t, type_id, data, bits_offset, show);
+		show->state.member = m;
+
+		if (show->state.depth_check != show->state.depth + 1)
+			return;
+		show->state.depth_check = 0;
+
+		if (show->state.depth_to_show <= show->state.depth)
+			return;
+		/*
+		 * Reaching here indicates we have recursed and found
+		 * non-zero array member(s).
+		 */
+	}
+	__btf_array_show(btf, t, type_id, data, bits_offset, show);
+}
+
+static struct btf_kind_operations array_ops = {
+	.check_meta = btf_array_check_meta,
+	.resolve = btf_array_resolve,
+	.check_member = btf_array_check_member,
+	.check_kflag_member = btf_generic_check_kflag_member,
+	.log_details = btf_array_log,
+	.show = btf_array_show,
+};
+
+static int btf_struct_check_member(struct btf_verifier_env *env,
+				   const struct btf_type *struct_type,
+				   const struct btf_member *member,
+				   const struct btf_type *member_type)
+{
+	u32 struct_bits_off = member->offset;
+	u32 struct_size, bytes_offset;
+
+	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member is not byte aligned");
+		return -EINVAL;
+	}
+
+	struct_size = struct_type->size;
+	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
+	if (struct_size - bytes_offset < member_type->size) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member exceeds struct_size");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static s32 btf_struct_check_meta(struct btf_verifier_env *env,
+				 const struct btf_type *t,
+				 u32 meta_left)
+{
+	bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
+	const struct btf_member *member;
+	u32 meta_needed, last_offset;
+	struct btf *btf = env->btf;
+	u32 struct_size = t->size;
+	u32 offset;
+	u16 i;
+
+	meta_needed = btf_type_vlen(t) * sizeof(*member);
+	if (meta_left < meta_needed) {
+		btf_verifier_log_basic(env, t,
+				       "meta_left:%u meta_needed:%u",
+				       meta_left, meta_needed);
+		return -EINVAL;
+	}
+
+	/* struct type either no name or a valid one */
+	if (t->name_off &&
+	    !btf_name_valid_identifier(env->btf, t->name_off)) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	last_offset = 0;
+	for_each_member(i, t, member) {
+		if (!btf_name_offset_valid(btf, member->name_off)) {
+			btf_verifier_log_member(env, t, member,
+						"Invalid member name_offset:%u",
+						member->name_off);
+			return -EINVAL;
+		}
+
+		/* struct member either no name or a valid one */
+		if (member->name_off &&
+		    !btf_name_valid_identifier(btf, member->name_off)) {
+			btf_verifier_log_member(env, t, member, "Invalid name");
+			return -EINVAL;
+		}
+		/* A member cannot be in type void */
+		if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
+			btf_verifier_log_member(env, t, member,
+						"Invalid type_id");
+			return -EINVAL;
+		}
+
+		offset = __btf_member_bit_offset(t, member);
+		if (is_union && offset) {
+			btf_verifier_log_member(env, t, member,
+						"Invalid member bits_offset");
+			return -EINVAL;
+		}
+
+		/*
+		 * ">" instead of ">=" because the last member could be
+		 * "char a[0];"
+		 */
+		if (last_offset > offset) {
+			btf_verifier_log_member(env, t, member,
+						"Invalid member bits_offset");
+			return -EINVAL;
+		}
+
+		if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
+			btf_verifier_log_member(env, t, member,
+						"Member bits_offset exceeds its struct size");
+			return -EINVAL;
+		}
+
+		btf_verifier_log_member(env, t, member, NULL);
+		last_offset = offset;
+	}
+
+	return meta_needed;
+}
+
+static int btf_struct_resolve(struct btf_verifier_env *env,
+			      const struct resolve_vertex *v)
+{
+	const struct btf_member *member;
+	int err;
+	u16 i;
+
+	/* Before continue resolving the next_member,
+	 * ensure the last member is indeed resolved to a
+	 * type with size info.
+	 */
+	if (v->next_member) {
+		const struct btf_type *last_member_type;
+		const struct btf_member *last_member;
+		u32 last_member_type_id;
+
+		last_member = btf_type_member(v->t) + v->next_member - 1;
+		last_member_type_id = last_member->type;
+		if (WARN_ON_ONCE(!env_type_is_resolved(env,
+						       last_member_type_id)))
+			return -EINVAL;
+
+		last_member_type = btf_type_by_id(env->btf,
+						  last_member_type_id);
+		if (btf_type_kflag(v->t))
+			err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
+								last_member,
+								last_member_type);
+		else
+			err = btf_type_ops(last_member_type)->check_member(env, v->t,
+								last_member,
+								last_member_type);
+		if (err)
+			return err;
+	}
+
+	for_each_member_from(i, v->next_member, v->t, member) {
+		u32 member_type_id = member->type;
+		const struct btf_type *member_type = btf_type_by_id(env->btf,
+								member_type_id);
+
+		if (btf_type_nosize_or_null(member_type) ||
+		    btf_type_is_resolve_source_only(member_type)) {
+			btf_verifier_log_member(env, v->t, member,
+						"Invalid member");
+			return -EINVAL;
+		}
+
+		if (!env_type_is_resolve_sink(env, member_type) &&
+		    !env_type_is_resolved(env, member_type_id)) {
+			env_stack_set_next_member(env, i + 1);
+			return env_stack_push(env, member_type, member_type_id);
+		}
+
+		if (btf_type_kflag(v->t))
+			err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
+									    member,
+									    member_type);
+		else
+			err = btf_type_ops(member_type)->check_member(env, v->t,
+								      member,
+								      member_type);
+		if (err)
+			return err;
+	}
+
+	env_stack_pop_resolved(env, 0, 0);
+
+	return 0;
+}
+
+static void btf_struct_log(struct btf_verifier_env *env,
+			   const struct btf_type *t)
+{
+	btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
+}
+
+enum btf_field_type {
+	BTF_FIELD_SPIN_LOCK,
+	BTF_FIELD_TIMER,
+	BTF_FIELD_KPTR,
+};
+
+enum {
+	BTF_FIELD_IGNORE = 0,
+	BTF_FIELD_FOUND  = 1,
+};
+
+struct btf_field_info {
+	u32 type_id;
+	u32 off;
+	enum bpf_kptr_type type;
+};
+
+static int btf_find_struct(const struct btf *btf, const struct btf_type *t,
+			   u32 off, int sz, struct btf_field_info *info)
+{
+	if (!__btf_type_is_struct(t))
+		return BTF_FIELD_IGNORE;
+	if (t->size != sz)
+		return BTF_FIELD_IGNORE;
+	info->off = off;
+	return BTF_FIELD_FOUND;
+}
+
+static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
+			 u32 off, int sz, struct btf_field_info *info)
+{
+	enum bpf_kptr_type type;
+	u32 res_id;
+
+	/* For PTR, sz is always == 8 */
+	if (!btf_type_is_ptr(t))
+		return BTF_FIELD_IGNORE;
+	t = btf_type_by_id(btf, t->type);
+
+	if (!btf_type_is_type_tag(t))
+		return BTF_FIELD_IGNORE;
+	/* Reject extra tags */
+	if (btf_type_is_type_tag(btf_type_by_id(btf, t->type)))
+		return -EINVAL;
+	if (!strcmp("kptr", __btf_name_by_offset(btf, t->name_off)))
+		type = BPF_KPTR_UNREF;
+	else if (!strcmp("kptr_ref", __btf_name_by_offset(btf, t->name_off)))
+		type = BPF_KPTR_REF;
+	else
+		return -EINVAL;
+
+	/* Get the base type */
+	t = btf_type_skip_modifiers(btf, t->type, &res_id);
+	/* Only pointer to struct is allowed */
+	if (!__btf_type_is_struct(t))
+		return -EINVAL;
+
+	info->type_id = res_id;
+	info->off = off;
+	info->type = type;
+	return BTF_FIELD_FOUND;
+}
+
+static int btf_find_struct_field(const struct btf *btf, const struct btf_type *t,
+				 const char *name, int sz, int align,
+				 enum btf_field_type field_type,
+				 struct btf_field_info *info, int info_cnt)
+{
+	const struct btf_member *member;
+	struct btf_field_info tmp;
+	int ret, idx = 0;
+	u32 i, off;
+
+	for_each_member(i, t, member) {
+		const struct btf_type *member_type = btf_type_by_id(btf,
+								    member->type);
+
+		if (name && strcmp(__btf_name_by_offset(btf, member_type->name_off), name))
+			continue;
+
+		off = __btf_member_bit_offset(t, member);
+		if (off % 8)
+			/* valid C code cannot generate such BTF */
+			return -EINVAL;
+		off /= 8;
+		if (off % align)
+			return -EINVAL;
+
+		switch (field_type) {
+		case BTF_FIELD_SPIN_LOCK:
+		case BTF_FIELD_TIMER:
+			ret = btf_find_struct(btf, member_type, off, sz,
+					      idx < info_cnt ? &info[idx] : &tmp);
+			if (ret < 0)
+				return ret;
+			break;
+		case BTF_FIELD_KPTR:
+			ret = btf_find_kptr(btf, member_type, off, sz,
+					    idx < info_cnt ? &info[idx] : &tmp);
+			if (ret < 0)
+				return ret;
+			break;
+		default:
+			return -EFAULT;
+		}
+
+		if (ret == BTF_FIELD_IGNORE)
+			continue;
+		if (idx >= info_cnt)
+			return -E2BIG;
+		++idx;
+	}
+	return idx;
+}
+
+static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
+				const char *name, int sz, int align,
+				enum btf_field_type field_type,
+				struct btf_field_info *info, int info_cnt)
+{
+	const struct btf_var_secinfo *vsi;
+	struct btf_field_info tmp;
+	int ret, idx = 0;
+	u32 i, off;
+
+	for_each_vsi(i, t, vsi) {
+		const struct btf_type *var = btf_type_by_id(btf, vsi->type);
+		const struct btf_type *var_type = btf_type_by_id(btf, var->type);
+
+		off = vsi->offset;
+
+		if (name && strcmp(__btf_name_by_offset(btf, var_type->name_off), name))
+			continue;
+		if (vsi->size != sz)
+			continue;
+		if (off % align)
+			return -EINVAL;
+
+		switch (field_type) {
+		case BTF_FIELD_SPIN_LOCK:
+		case BTF_FIELD_TIMER:
+			ret = btf_find_struct(btf, var_type, off, sz,
+					      idx < info_cnt ? &info[idx] : &tmp);
+			if (ret < 0)
+				return ret;
+			break;
+		case BTF_FIELD_KPTR:
+			ret = btf_find_kptr(btf, var_type, off, sz,
+					    idx < info_cnt ? &info[idx] : &tmp);
+			if (ret < 0)
+				return ret;
+			break;
+		default:
+			return -EFAULT;
+		}
+
+		if (ret == BTF_FIELD_IGNORE)
+			continue;
+		if (idx >= info_cnt)
+			return -E2BIG;
+		++idx;
+	}
+	return idx;
+}
+
+static int btf_find_field(const struct btf *btf, const struct btf_type *t,
+			  enum btf_field_type field_type,
+			  struct btf_field_info *info, int info_cnt)
+{
+	const char *name;
+	int sz, align;
+
+	switch (field_type) {
+	case BTF_FIELD_SPIN_LOCK:
+		name = "bpf_spin_lock";
+		sz = sizeof(struct bpf_spin_lock);
+		align = __alignof__(struct bpf_spin_lock);
+		break;
+	case BTF_FIELD_TIMER:
+		name = "bpf_timer";
+		sz = sizeof(struct bpf_timer);
+		align = __alignof__(struct bpf_timer);
+		break;
+	case BTF_FIELD_KPTR:
+		name = NULL;
+		sz = sizeof(u64);
+		align = 8;
+		break;
+	default:
+		return -EFAULT;
+	}
+
+	if (__btf_type_is_struct(t))
+		return btf_find_struct_field(btf, t, name, sz, align, field_type, info, info_cnt);
+	else if (btf_type_is_datasec(t))
+		return btf_find_datasec_var(btf, t, name, sz, align, field_type, info, info_cnt);
+	return -EINVAL;
+}
+
+/* find 'struct bpf_spin_lock' in map value.
+ * return >= 0 offset if found
+ * and < 0 in case of error
+ */
+int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t)
+{
+	struct btf_field_info info;
+	int ret;
+
+	ret = btf_find_field(btf, t, BTF_FIELD_SPIN_LOCK, &info, 1);
+	if (ret < 0)
+		return ret;
+	if (!ret)
+		return -ENOENT;
+	return info.off;
+}
+
+int btf_find_timer(const struct btf *btf, const struct btf_type *t)
+{
+	struct btf_field_info info;
+	int ret;
+
+	ret = btf_find_field(btf, t, BTF_FIELD_TIMER, &info, 1);
+	if (ret < 0)
+		return ret;
+	if (!ret)
+		return -ENOENT;
+	return info.off;
+}
+
+struct bpf_map_value_off *btf_parse_kptrs(const struct btf *btf,
+					  const struct btf_type *t)
+{
+	struct btf_field_info info_arr[BPF_MAP_VALUE_OFF_MAX];
+	struct bpf_map_value_off *tab;
+	struct btf *kernel_btf = NULL;
+	struct module *mod = NULL;
+	int ret, i, nr_off;
+
+	ret = btf_find_field(btf, t, BTF_FIELD_KPTR, info_arr, ARRAY_SIZE(info_arr));
+	if (ret < 0)
+		return ERR_PTR(ret);
+	if (!ret)
+		return NULL;
+
+	nr_off = ret;
+	tab = kzalloc(offsetof(struct bpf_map_value_off, off[nr_off]), GFP_KERNEL | __GFP_NOWARN);
+	if (!tab)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < nr_off; i++) {
+		const struct btf_type *t;
+		s32 id;
+
+		/* Find type in map BTF, and use it to look up the matching type
+		 * in vmlinux or module BTFs, by name and kind.
+		 */
+		t = btf_type_by_id(btf, info_arr[i].type_id);
+		id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info),
+				     &kernel_btf);
+		if (id < 0) {
+			ret = id;
+			goto end;
+		}
+
+		/* Find and stash the function pointer for the destruction function that
+		 * needs to be eventually invoked from the map free path.
+		 */
+		if (info_arr[i].type == BPF_KPTR_REF) {
+			const struct btf_type *dtor_func;
+			const char *dtor_func_name;
+			unsigned long addr;
+			s32 dtor_btf_id;
+
+			/* This call also serves as a whitelist of allowed objects that
+			 * can be used as a referenced pointer and be stored in a map at
+			 * the same time.
+			 */
+			dtor_btf_id = btf_find_dtor_kfunc(kernel_btf, id);
+			if (dtor_btf_id < 0) {
+				ret = dtor_btf_id;
+				goto end_btf;
+			}
+
+			dtor_func = btf_type_by_id(kernel_btf, dtor_btf_id);
+			if (!dtor_func) {
+				ret = -ENOENT;
+				goto end_btf;
+			}
+
+			if (btf_is_module(kernel_btf)) {
+				mod = btf_try_get_module(kernel_btf);
+				if (!mod) {
+					ret = -ENXIO;
+					goto end_btf;
+				}
+			}
+
+			/* We already verified dtor_func to be btf_type_is_func
+			 * in register_btf_id_dtor_kfuncs.
+			 */
+			dtor_func_name = __btf_name_by_offset(kernel_btf, dtor_func->name_off);
+			addr = kallsyms_lookup_name(dtor_func_name);
+			if (!addr) {
+				ret = -EINVAL;
+				goto end_mod;
+			}
+			tab->off[i].kptr.dtor = (void *)addr;
+		}
+
+		tab->off[i].offset = info_arr[i].off;
+		tab->off[i].type = info_arr[i].type;
+		tab->off[i].kptr.btf_id = id;
+		tab->off[i].kptr.btf = kernel_btf;
+		tab->off[i].kptr.module = mod;
+	}
+	tab->nr_off = nr_off;
+	return tab;
+end_mod:
+	module_put(mod);
+end_btf:
+	btf_put(kernel_btf);
+end:
+	while (i--) {
+		btf_put(tab->off[i].kptr.btf);
+		if (tab->off[i].kptr.module)
+			module_put(tab->off[i].kptr.module);
+	}
+	kfree(tab);
+	return ERR_PTR(ret);
+}
+
+static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
+			      u32 type_id, void *data, u8 bits_offset,
+			      struct btf_show *show)
+{
+	const struct btf_member *member;
+	void *safe_data;
+	u32 i;
+
+	safe_data = btf_show_start_struct_type(show, t, type_id, data);
+	if (!safe_data)
+		return;
+
+	for_each_member(i, t, member) {
+		const struct btf_type *member_type = btf_type_by_id(btf,
+								member->type);
+		const struct btf_kind_operations *ops;
+		u32 member_offset, bitfield_size;
+		u32 bytes_offset;
+		u8 bits8_offset;
+
+		btf_show_start_member(show, member);
+
+		member_offset = __btf_member_bit_offset(t, member);
+		bitfield_size = __btf_member_bitfield_size(t, member);
+		bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
+		bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
+		if (bitfield_size) {
+			safe_data = btf_show_start_type(show, member_type,
+							member->type,
+							data + bytes_offset);
+			if (safe_data)
+				btf_bitfield_show(safe_data,
+						  bits8_offset,
+						  bitfield_size, show);
+			btf_show_end_type(show);
+		} else {
+			ops = btf_type_ops(member_type);
+			ops->show(btf, member_type, member->type,
+				  data + bytes_offset, bits8_offset, show);
+		}
+
+		btf_show_end_member(show);
+	}
+
+	btf_show_end_struct_type(show);
+}
+
+static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
+			    u32 type_id, void *data, u8 bits_offset,
+			    struct btf_show *show)
+{
+	const struct btf_member *m = show->state.member;
+
+	/*
+	 * First check if any members would be shown (are non-zero).
+	 * See comments above "struct btf_show" definition for more
+	 * details on how this works at a high-level.
+	 */
+	if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
+		if (!show->state.depth_check) {
+			show->state.depth_check = show->state.depth + 1;
+			show->state.depth_to_show = 0;
+		}
+		__btf_struct_show(btf, t, type_id, data, bits_offset, show);
+		/* Restore saved member data here */
+		show->state.member = m;
+		if (show->state.depth_check != show->state.depth + 1)
+			return;
+		show->state.depth_check = 0;
+
+		if (show->state.depth_to_show <= show->state.depth)
+			return;
+		/*
+		 * Reaching here indicates we have recursed and found
+		 * non-zero child values.
+		 */
+	}
+
+	__btf_struct_show(btf, t, type_id, data, bits_offset, show);
+}
+
+static struct btf_kind_operations struct_ops = {
+	.check_meta = btf_struct_check_meta,
+	.resolve = btf_struct_resolve,
+	.check_member = btf_struct_check_member,
+	.check_kflag_member = btf_generic_check_kflag_member,
+	.log_details = btf_struct_log,
+	.show = btf_struct_show,
+};
+
+static int btf_enum_check_member(struct btf_verifier_env *env,
+				 const struct btf_type *struct_type,
+				 const struct btf_member *member,
+				 const struct btf_type *member_type)
+{
+	u32 struct_bits_off = member->offset;
+	u32 struct_size, bytes_offset;
+
+	if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member is not byte aligned");
+		return -EINVAL;
+	}
+
+	struct_size = struct_type->size;
+	bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
+	if (struct_size - bytes_offset < member_type->size) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member exceeds struct_size");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
+				       const struct btf_type *struct_type,
+				       const struct btf_member *member,
+				       const struct btf_type *member_type)
+{
+	u32 struct_bits_off, nr_bits, bytes_end, struct_size;
+	u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
+
+	struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
+	nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
+	if (!nr_bits) {
+		if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
+			btf_verifier_log_member(env, struct_type, member,
+						"Member is not byte aligned");
+			return -EINVAL;
+		}
+
+		nr_bits = int_bitsize;
+	} else if (nr_bits > int_bitsize) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Invalid member bitfield_size");
+		return -EINVAL;
+	}
+
+	struct_size = struct_type->size;
+	bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
+	if (struct_size < bytes_end) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member exceeds struct_size");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static s32 btf_enum_check_meta(struct btf_verifier_env *env,
+			       const struct btf_type *t,
+			       u32 meta_left)
+{
+	const struct btf_enum *enums = btf_type_enum(t);
+	struct btf *btf = env->btf;
+	const char *fmt_str;
+	u16 i, nr_enums;
+	u32 meta_needed;
+
+	nr_enums = btf_type_vlen(t);
+	meta_needed = nr_enums * sizeof(*enums);
+
+	if (meta_left < meta_needed) {
+		btf_verifier_log_basic(env, t,
+				       "meta_left:%u meta_needed:%u",
+				       meta_left, meta_needed);
+		return -EINVAL;
+	}
+
+	if (t->size > 8 || !is_power_of_2(t->size)) {
+		btf_verifier_log_type(env, t, "Unexpected size");
+		return -EINVAL;
+	}
+
+	/* enum type either no name or a valid one */
+	if (t->name_off &&
+	    !btf_name_valid_identifier(env->btf, t->name_off)) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	for (i = 0; i < nr_enums; i++) {
+		if (!btf_name_offset_valid(btf, enums[i].name_off)) {
+			btf_verifier_log(env, "\tInvalid name_offset:%u",
+					 enums[i].name_off);
+			return -EINVAL;
+		}
+
+		/* enum member must have a valid name */
+		if (!enums[i].name_off ||
+		    !btf_name_valid_identifier(btf, enums[i].name_off)) {
+			btf_verifier_log_type(env, t, "Invalid name");
+			return -EINVAL;
+		}
+
+		if (env->log.level == BPF_LOG_KERNEL)
+			continue;
+		fmt_str = btf_type_kflag(t) ? "\t%s val=%d\n" : "\t%s val=%u\n";
+		btf_verifier_log(env, fmt_str,
+				 __btf_name_by_offset(btf, enums[i].name_off),
+				 enums[i].val);
+	}
+
+	return meta_needed;
+}
+
+static void btf_enum_log(struct btf_verifier_env *env,
+			 const struct btf_type *t)
+{
+	btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
+}
+
+static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
+			  u32 type_id, void *data, u8 bits_offset,
+			  struct btf_show *show)
+{
+	const struct btf_enum *enums = btf_type_enum(t);
+	u32 i, nr_enums = btf_type_vlen(t);
+	void *safe_data;
+	int v;
+
+	safe_data = btf_show_start_type(show, t, type_id, data);
+	if (!safe_data)
+		return;
+
+	v = *(int *)safe_data;
+
+	for (i = 0; i < nr_enums; i++) {
+		if (v != enums[i].val)
+			continue;
+
+		btf_show_type_value(show, "%s",
+				    __btf_name_by_offset(btf,
+							 enums[i].name_off));
+
+		btf_show_end_type(show);
+		return;
+	}
+
+	if (btf_type_kflag(t))
+		btf_show_type_value(show, "%d", v);
+	else
+		btf_show_type_value(show, "%u", v);
+	btf_show_end_type(show);
+}
+
+static struct btf_kind_operations enum_ops = {
+	.check_meta = btf_enum_check_meta,
+	.resolve = btf_df_resolve,
+	.check_member = btf_enum_check_member,
+	.check_kflag_member = btf_enum_check_kflag_member,
+	.log_details = btf_enum_log,
+	.show = btf_enum_show,
+};
+
+static s32 btf_enum64_check_meta(struct btf_verifier_env *env,
+				 const struct btf_type *t,
+				 u32 meta_left)
+{
+	const struct btf_enum64 *enums = btf_type_enum64(t);
+	struct btf *btf = env->btf;
+	const char *fmt_str;
+	u16 i, nr_enums;
+	u32 meta_needed;
+
+	nr_enums = btf_type_vlen(t);
+	meta_needed = nr_enums * sizeof(*enums);
+
+	if (meta_left < meta_needed) {
+		btf_verifier_log_basic(env, t,
+				       "meta_left:%u meta_needed:%u",
+				       meta_left, meta_needed);
+		return -EINVAL;
+	}
+
+	if (t->size > 8 || !is_power_of_2(t->size)) {
+		btf_verifier_log_type(env, t, "Unexpected size");
+		return -EINVAL;
+	}
+
+	/* enum type either no name or a valid one */
+	if (t->name_off &&
+	    !btf_name_valid_identifier(env->btf, t->name_off)) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	for (i = 0; i < nr_enums; i++) {
+		if (!btf_name_offset_valid(btf, enums[i].name_off)) {
+			btf_verifier_log(env, "\tInvalid name_offset:%u",
+					 enums[i].name_off);
+			return -EINVAL;
+		}
+
+		/* enum member must have a valid name */
+		if (!enums[i].name_off ||
+		    !btf_name_valid_identifier(btf, enums[i].name_off)) {
+			btf_verifier_log_type(env, t, "Invalid name");
+			return -EINVAL;
+		}
+
+		if (env->log.level == BPF_LOG_KERNEL)
+			continue;
+
+		fmt_str = btf_type_kflag(t) ? "\t%s val=%lld\n" : "\t%s val=%llu\n";
+		btf_verifier_log(env, fmt_str,
+				 __btf_name_by_offset(btf, enums[i].name_off),
+				 btf_enum64_value(enums + i));
+	}
+
+	return meta_needed;
+}
+
+static void btf_enum64_show(const struct btf *btf, const struct btf_type *t,
+			    u32 type_id, void *data, u8 bits_offset,
+			    struct btf_show *show)
+{
+	const struct btf_enum64 *enums = btf_type_enum64(t);
+	u32 i, nr_enums = btf_type_vlen(t);
+	void *safe_data;
+	s64 v;
+
+	safe_data = btf_show_start_type(show, t, type_id, data);
+	if (!safe_data)
+		return;
+
+	v = *(u64 *)safe_data;
+
+	for (i = 0; i < nr_enums; i++) {
+		if (v != btf_enum64_value(enums + i))
+			continue;
+
+		btf_show_type_value(show, "%s",
+				    __btf_name_by_offset(btf,
+							 enums[i].name_off));
+
+		btf_show_end_type(show);
+		return;
+	}
+
+	if (btf_type_kflag(t))
+		btf_show_type_value(show, "%lld", v);
+	else
+		btf_show_type_value(show, "%llu", v);
+	btf_show_end_type(show);
+}
+
+static struct btf_kind_operations enum64_ops = {
+	.check_meta = btf_enum64_check_meta,
+	.resolve = btf_df_resolve,
+	.check_member = btf_enum_check_member,
+	.check_kflag_member = btf_enum_check_kflag_member,
+	.log_details = btf_enum_log,
+	.show = btf_enum64_show,
+};
+
+static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
+				     const struct btf_type *t,
+				     u32 meta_left)
+{
+	u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
+
+	if (meta_left < meta_needed) {
+		btf_verifier_log_basic(env, t,
+				       "meta_left:%u meta_needed:%u",
+				       meta_left, meta_needed);
+		return -EINVAL;
+	}
+
+	if (t->name_off) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	return meta_needed;
+}
+
+static void btf_func_proto_log(struct btf_verifier_env *env,
+			       const struct btf_type *t)
+{
+	const struct btf_param *args = (const struct btf_param *)(t + 1);
+	u16 nr_args = btf_type_vlen(t), i;
+
+	btf_verifier_log(env, "return=%u args=(", t->type);
+	if (!nr_args) {
+		btf_verifier_log(env, "void");
+		goto done;
+	}
+
+	if (nr_args == 1 && !args[0].type) {
+		/* Only one vararg */
+		btf_verifier_log(env, "vararg");
+		goto done;
+	}
+
+	btf_verifier_log(env, "%u %s", args[0].type,
+			 __btf_name_by_offset(env->btf,
+					      args[0].name_off));
+	for (i = 1; i < nr_args - 1; i++)
+		btf_verifier_log(env, ", %u %s", args[i].type,
+				 __btf_name_by_offset(env->btf,
+						      args[i].name_off));
+
+	if (nr_args > 1) {
+		const struct btf_param *last_arg = &args[nr_args - 1];
+
+		if (last_arg->type)
+			btf_verifier_log(env, ", %u %s", last_arg->type,
+					 __btf_name_by_offset(env->btf,
+							      last_arg->name_off));
+		else
+			btf_verifier_log(env, ", vararg");
+	}
+
+done:
+	btf_verifier_log(env, ")");
+}
+
+static struct btf_kind_operations func_proto_ops = {
+	.check_meta = btf_func_proto_check_meta,
+	.resolve = btf_df_resolve,
+	/*
+	 * BTF_KIND_FUNC_PROTO cannot be directly referred by
+	 * a struct's member.
+	 *
+	 * It should be a function pointer instead.
+	 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
+	 *
+	 * Hence, there is no btf_func_check_member().
+	 */
+	.check_member = btf_df_check_member,
+	.check_kflag_member = btf_df_check_kflag_member,
+	.log_details = btf_func_proto_log,
+	.show = btf_df_show,
+};
+
+static s32 btf_func_check_meta(struct btf_verifier_env *env,
+			       const struct btf_type *t,
+			       u32 meta_left)
+{
+	if (!t->name_off ||
+	    !btf_name_valid_identifier(env->btf, t->name_off)) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
+	if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
+		btf_verifier_log_type(env, t, "Invalid func linkage");
+		return -EINVAL;
+	}
+
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	return 0;
+}
+
+static int btf_func_resolve(struct btf_verifier_env *env,
+			    const struct resolve_vertex *v)
+{
+	const struct btf_type *t = v->t;
+	u32 next_type_id = t->type;
+	int err;
+
+	err = btf_func_check(env, t);
+	if (err)
+		return err;
+
+	env_stack_pop_resolved(env, next_type_id, 0);
+	return 0;
+}
+
+static struct btf_kind_operations func_ops = {
+	.check_meta = btf_func_check_meta,
+	.resolve = btf_func_resolve,
+	.check_member = btf_df_check_member,
+	.check_kflag_member = btf_df_check_kflag_member,
+	.log_details = btf_ref_type_log,
+	.show = btf_df_show,
+};
+
+static s32 btf_var_check_meta(struct btf_verifier_env *env,
+			      const struct btf_type *t,
+			      u32 meta_left)
+{
+	const struct btf_var *var;
+	u32 meta_needed = sizeof(*var);
+
+	if (meta_left < meta_needed) {
+		btf_verifier_log_basic(env, t,
+				       "meta_left:%u meta_needed:%u",
+				       meta_left, meta_needed);
+		return -EINVAL;
+	}
+
+	if (btf_type_vlen(t)) {
+		btf_verifier_log_type(env, t, "vlen != 0");
+		return -EINVAL;
+	}
+
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
+	if (!t->name_off ||
+	    !__btf_name_valid(env->btf, t->name_off)) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
+	/* A var cannot be in type void */
+	if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
+		btf_verifier_log_type(env, t, "Invalid type_id");
+		return -EINVAL;
+	}
+
+	var = btf_type_var(t);
+	if (var->linkage != BTF_VAR_STATIC &&
+	    var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
+		btf_verifier_log_type(env, t, "Linkage not supported");
+		return -EINVAL;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	return meta_needed;
+}
+
+static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
+{
+	const struct btf_var *var = btf_type_var(t);
+
+	btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
+}
+
+static const struct btf_kind_operations var_ops = {
+	.check_meta		= btf_var_check_meta,
+	.resolve		= btf_var_resolve,
+	.check_member		= btf_df_check_member,
+	.check_kflag_member	= btf_df_check_kflag_member,
+	.log_details		= btf_var_log,
+	.show			= btf_var_show,
+};
+
+static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
+				  const struct btf_type *t,
+				  u32 meta_left)
+{
+	const struct btf_var_secinfo *vsi;
+	u64 last_vsi_end_off = 0, sum = 0;
+	u32 i, meta_needed;
+
+	meta_needed = btf_type_vlen(t) * sizeof(*vsi);
+	if (meta_left < meta_needed) {
+		btf_verifier_log_basic(env, t,
+				       "meta_left:%u meta_needed:%u",
+				       meta_left, meta_needed);
+		return -EINVAL;
+	}
+
+	if (!t->size) {
+		btf_verifier_log_type(env, t, "size == 0");
+		return -EINVAL;
+	}
+
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
+	if (!t->name_off ||
+	    !btf_name_valid_section(env->btf, t->name_off)) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	for_each_vsi(i, t, vsi) {
+		/* A var cannot be in type void */
+		if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
+			btf_verifier_log_vsi(env, t, vsi,
+					     "Invalid type_id");
+			return -EINVAL;
+		}
+
+		if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
+			btf_verifier_log_vsi(env, t, vsi,
+					     "Invalid offset");
+			return -EINVAL;
+		}
+
+		if (!vsi->size || vsi->size > t->size) {
+			btf_verifier_log_vsi(env, t, vsi,
+					     "Invalid size");
+			return -EINVAL;
+		}
+
+		last_vsi_end_off = vsi->offset + vsi->size;
+		if (last_vsi_end_off > t->size) {
+			btf_verifier_log_vsi(env, t, vsi,
+					     "Invalid offset+size");
+			return -EINVAL;
+		}
+
+		btf_verifier_log_vsi(env, t, vsi, NULL);
+		sum += vsi->size;
+	}
+
+	if (t->size < sum) {
+		btf_verifier_log_type(env, t, "Invalid btf_info size");
+		return -EINVAL;
+	}
+
+	return meta_needed;
+}
+
+static int btf_datasec_resolve(struct btf_verifier_env *env,
+			       const struct resolve_vertex *v)
+{
+	const struct btf_var_secinfo *vsi;
+	struct btf *btf = env->btf;
+	u16 i;
+
+	env->resolve_mode = RESOLVE_TBD;
+	for_each_vsi_from(i, v->next_member, v->t, vsi) {
+		u32 var_type_id = vsi->type, type_id, type_size = 0;
+		const struct btf_type *var_type = btf_type_by_id(env->btf,
+								 var_type_id);
+		if (!var_type || !btf_type_is_var(var_type)) {
+			btf_verifier_log_vsi(env, v->t, vsi,
+					     "Not a VAR kind member");
+			return -EINVAL;
+		}
+
+		if (!env_type_is_resolve_sink(env, var_type) &&
+		    !env_type_is_resolved(env, var_type_id)) {
+			env_stack_set_next_member(env, i + 1);
+			return env_stack_push(env, var_type, var_type_id);
+		}
+
+		type_id = var_type->type;
+		if (!btf_type_id_size(btf, &type_id, &type_size)) {
+			btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
+			return -EINVAL;
+		}
+
+		if (vsi->size < type_size) {
+			btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
+			return -EINVAL;
+		}
+	}
+
+	env_stack_pop_resolved(env, 0, 0);
+	return 0;
+}
+
+static void btf_datasec_log(struct btf_verifier_env *env,
+			    const struct btf_type *t)
+{
+	btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
+}
+
+static void btf_datasec_show(const struct btf *btf,
+			     const struct btf_type *t, u32 type_id,
+			     void *data, u8 bits_offset,
+			     struct btf_show *show)
+{
+	const struct btf_var_secinfo *vsi;
+	const struct btf_type *var;
+	u32 i;
+
+	if (!btf_show_start_type(show, t, type_id, data))
+		return;
+
+	btf_show_type_value(show, "section (\"%s\") = {",
+			    __btf_name_by_offset(btf, t->name_off));
+	for_each_vsi(i, t, vsi) {
+		var = btf_type_by_id(btf, vsi->type);
+		if (i)
+			btf_show(show, ",");
+		btf_type_ops(var)->show(btf, var, vsi->type,
+					data + vsi->offset, bits_offset, show);
+	}
+	btf_show_end_type(show);
+}
+
+static const struct btf_kind_operations datasec_ops = {
+	.check_meta		= btf_datasec_check_meta,
+	.resolve		= btf_datasec_resolve,
+	.check_member		= btf_df_check_member,
+	.check_kflag_member	= btf_df_check_kflag_member,
+	.log_details		= btf_datasec_log,
+	.show			= btf_datasec_show,
+};
+
+static s32 btf_float_check_meta(struct btf_verifier_env *env,
+				const struct btf_type *t,
+				u32 meta_left)
+{
+	if (btf_type_vlen(t)) {
+		btf_verifier_log_type(env, t, "vlen != 0");
+		return -EINVAL;
+	}
+
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
+	if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
+	    t->size != 16) {
+		btf_verifier_log_type(env, t, "Invalid type_size");
+		return -EINVAL;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	return 0;
+}
+
+static int btf_float_check_member(struct btf_verifier_env *env,
+				  const struct btf_type *struct_type,
+				  const struct btf_member *member,
+				  const struct btf_type *member_type)
+{
+	u64 start_offset_bytes;
+	u64 end_offset_bytes;
+	u64 misalign_bits;
+	u64 align_bytes;
+	u64 align_bits;
+
+	/* Different architectures have different alignment requirements, so
+	 * here we check only for the reasonable minimum. This way we ensure
+	 * that types after CO-RE can pass the kernel BTF verifier.
+	 */
+	align_bytes = min_t(u64, sizeof(void *), member_type->size);
+	align_bits = align_bytes * BITS_PER_BYTE;
+	div64_u64_rem(member->offset, align_bits, &misalign_bits);
+	if (misalign_bits) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member is not properly aligned");
+		return -EINVAL;
+	}
+
+	start_offset_bytes = member->offset / BITS_PER_BYTE;
+	end_offset_bytes = start_offset_bytes + member_type->size;
+	if (end_offset_bytes > struct_type->size) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member exceeds struct_size");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void btf_float_log(struct btf_verifier_env *env,
+			  const struct btf_type *t)
+{
+	btf_verifier_log(env, "size=%u", t->size);
+}
+
+static const struct btf_kind_operations float_ops = {
+	.check_meta = btf_float_check_meta,
+	.resolve = btf_df_resolve,
+	.check_member = btf_float_check_member,
+	.check_kflag_member = btf_generic_check_kflag_member,
+	.log_details = btf_float_log,
+	.show = btf_df_show,
+};
+
+static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
+			      const struct btf_type *t,
+			      u32 meta_left)
+{
+	const struct btf_decl_tag *tag;
+	u32 meta_needed = sizeof(*tag);
+	s32 component_idx;
+	const char *value;
+
+	if (meta_left < meta_needed) {
+		btf_verifier_log_basic(env, t,
+				       "meta_left:%u meta_needed:%u",
+				       meta_left, meta_needed);
+		return -EINVAL;
+	}
+
+	value = btf_name_by_offset(env->btf, t->name_off);
+	if (!value || !value[0]) {
+		btf_verifier_log_type(env, t, "Invalid value");
+		return -EINVAL;
+	}
+
+	if (btf_type_vlen(t)) {
+		btf_verifier_log_type(env, t, "vlen != 0");
+		return -EINVAL;
+	}
+
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
+	component_idx = btf_type_decl_tag(t)->component_idx;
+	if (component_idx < -1) {
+		btf_verifier_log_type(env, t, "Invalid component_idx");
+		return -EINVAL;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	return meta_needed;
+}
+
+static int btf_decl_tag_resolve(struct btf_verifier_env *env,
+			   const struct resolve_vertex *v)
+{
+	const struct btf_type *next_type;
+	const struct btf_type *t = v->t;
+	u32 next_type_id = t->type;
+	struct btf *btf = env->btf;
+	s32 component_idx;
+	u32 vlen;
+
+	next_type = btf_type_by_id(btf, next_type_id);
+	if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
+		btf_verifier_log_type(env, v->t, "Invalid type_id");
+		return -EINVAL;
+	}
+
+	if (!env_type_is_resolve_sink(env, next_type) &&
+	    !env_type_is_resolved(env, next_type_id))
+		return env_stack_push(env, next_type, next_type_id);
+
+	component_idx = btf_type_decl_tag(t)->component_idx;
+	if (component_idx != -1) {
+		if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
+			btf_verifier_log_type(env, v->t, "Invalid component_idx");
+			return -EINVAL;
+		}
+
+		if (btf_type_is_struct(next_type)) {
+			vlen = btf_type_vlen(next_type);
+		} else {
+			/* next_type should be a function */
+			next_type = btf_type_by_id(btf, next_type->type);
+			vlen = btf_type_vlen(next_type);
+		}
+
+		if ((u32)component_idx >= vlen) {
+			btf_verifier_log_type(env, v->t, "Invalid component_idx");
+			return -EINVAL;
+		}
+	}
+
+	env_stack_pop_resolved(env, next_type_id, 0);
+
+	return 0;
+}
+
+static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
+{
+	btf_verifier_log(env, "type=%u component_idx=%d", t->type,
+			 btf_type_decl_tag(t)->component_idx);
+}
+
+static const struct btf_kind_operations decl_tag_ops = {
+	.check_meta = btf_decl_tag_check_meta,
+	.resolve = btf_decl_tag_resolve,
+	.check_member = btf_df_check_member,
+	.check_kflag_member = btf_df_check_kflag_member,
+	.log_details = btf_decl_tag_log,
+	.show = btf_df_show,
+};
+
+static int btf_func_proto_check(struct btf_verifier_env *env,
+				const struct btf_type *t)
+{
+	const struct btf_type *ret_type;
+	const struct btf_param *args;
+	const struct btf *btf;
+	u16 nr_args, i;
+	int err;
+
+	btf = env->btf;
+	args = (const struct btf_param *)(t + 1);
+	nr_args = btf_type_vlen(t);
+
+	/* Check func return type which could be "void" (t->type == 0) */
+	if (t->type) {
+		u32 ret_type_id = t->type;
+
+		ret_type = btf_type_by_id(btf, ret_type_id);
+		if (!ret_type) {
+			btf_verifier_log_type(env, t, "Invalid return type");
+			return -EINVAL;
+		}
+
+		if (btf_type_is_resolve_source_only(ret_type)) {
+			btf_verifier_log_type(env, t, "Invalid return type");
+			return -EINVAL;
+		}
+
+		if (btf_type_needs_resolve(ret_type) &&
+		    !env_type_is_resolved(env, ret_type_id)) {
+			err = btf_resolve(env, ret_type, ret_type_id);
+			if (err)
+				return err;
+		}
+
+		/* Ensure the return type is a type that has a size */
+		if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
+			btf_verifier_log_type(env, t, "Invalid return type");
+			return -EINVAL;
+		}
+	}
+
+	if (!nr_args)
+		return 0;
+
+	/* Last func arg type_id could be 0 if it is a vararg */
+	if (!args[nr_args - 1].type) {
+		if (args[nr_args - 1].name_off) {
+			btf_verifier_log_type(env, t, "Invalid arg#%u",
+					      nr_args);
+			return -EINVAL;
+		}
+		nr_args--;
+	}
+
+	err = 0;
+	for (i = 0; i < nr_args; i++) {
+		const struct btf_type *arg_type;
+		u32 arg_type_id;
+
+		arg_type_id = args[i].type;
+		arg_type = btf_type_by_id(btf, arg_type_id);
+		if (!arg_type) {
+			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
+			err = -EINVAL;
+			break;
+		}
+
+		if (btf_type_is_resolve_source_only(arg_type)) {
+			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
+			return -EINVAL;
+		}
+
+		if (args[i].name_off &&
+		    (!btf_name_offset_valid(btf, args[i].name_off) ||
+		     !btf_name_valid_identifier(btf, args[i].name_off))) {
+			btf_verifier_log_type(env, t,
+					      "Invalid arg#%u", i + 1);
+			err = -EINVAL;
+			break;
+		}
+
+		if (btf_type_needs_resolve(arg_type) &&
+		    !env_type_is_resolved(env, arg_type_id)) {
+			err = btf_resolve(env, arg_type, arg_type_id);
+			if (err)
+				break;
+		}
+
+		if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
+			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
+			err = -EINVAL;
+			break;
+		}
+	}
+
+	return err;
+}
+
+static int btf_func_check(struct btf_verifier_env *env,
+			  const struct btf_type *t)
+{
+	const struct btf_type *proto_type;
+	const struct btf_param *args;
+	const struct btf *btf;
+	u16 nr_args, i;
+
+	btf = env->btf;
+	proto_type = btf_type_by_id(btf, t->type);
+
+	if (!proto_type || !btf_type_is_func_proto(proto_type)) {
+		btf_verifier_log_type(env, t, "Invalid type_id");
+		return -EINVAL;
+	}
+
+	args = (const struct btf_param *)(proto_type + 1);
+	nr_args = btf_type_vlen(proto_type);
+	for (i = 0; i < nr_args; i++) {
+		if (!args[i].name_off && args[i].type) {
+			btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
+	[BTF_KIND_INT] = &int_ops,
+	[BTF_KIND_PTR] = &ptr_ops,
+	[BTF_KIND_ARRAY] = &array_ops,
+	[BTF_KIND_STRUCT] = &struct_ops,
+	[BTF_KIND_UNION] = &struct_ops,
+	[BTF_KIND_ENUM] = &enum_ops,
+	[BTF_KIND_FWD] = &fwd_ops,
+	[BTF_KIND_TYPEDEF] = &modifier_ops,
+	[BTF_KIND_VOLATILE] = &modifier_ops,
+	[BTF_KIND_CONST] = &modifier_ops,
+	[BTF_KIND_RESTRICT] = &modifier_ops,
+	[BTF_KIND_FUNC] = &func_ops,
+	[BTF_KIND_FUNC_PROTO] = &func_proto_ops,
+	[BTF_KIND_VAR] = &var_ops,
+	[BTF_KIND_DATASEC] = &datasec_ops,
+	[BTF_KIND_FLOAT] = &float_ops,
+	[BTF_KIND_DECL_TAG] = &decl_tag_ops,
+	[BTF_KIND_TYPE_TAG] = &modifier_ops,
+	[BTF_KIND_ENUM64] = &enum64_ops,
+};
+
+static s32 btf_check_meta(struct btf_verifier_env *env,
+			  const struct btf_type *t,
+			  u32 meta_left)
+{
+	u32 saved_meta_left = meta_left;
+	s32 var_meta_size;
+
+	if (meta_left < sizeof(*t)) {
+		btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
+				 env->log_type_id, meta_left, sizeof(*t));
+		return -EINVAL;
+	}
+	meta_left -= sizeof(*t);
+
+	if (t->info & ~BTF_INFO_MASK) {
+		btf_verifier_log(env, "[%u] Invalid btf_info:%x",
+				 env->log_type_id, t->info);
+		return -EINVAL;
+	}
+
+	if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
+	    BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
+		btf_verifier_log(env, "[%u] Invalid kind:%u",
+				 env->log_type_id, BTF_INFO_KIND(t->info));
+		return -EINVAL;
+	}
+
+	if (!btf_name_offset_valid(env->btf, t->name_off)) {
+		btf_verifier_log(env, "[%u] Invalid name_offset:%u",
+				 env->log_type_id, t->name_off);
+		return -EINVAL;
+	}
+
+	var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
+	if (var_meta_size < 0)
+		return var_meta_size;
+
+	meta_left -= var_meta_size;
+
+	return saved_meta_left - meta_left;
+}
+
+static int btf_check_all_metas(struct btf_verifier_env *env)
+{
+	struct btf *btf = env->btf;
+	struct btf_header *hdr;
+	void *cur, *end;
+
+	hdr = &btf->hdr;
+	cur = btf->nohdr_data + hdr->type_off;
+	end = cur + hdr->type_len;
+
+	env->log_type_id = btf->base_btf ? btf->start_id : 1;
+	while (cur < end) {
+		struct btf_type *t = cur;
+		s32 meta_size;
+
+		meta_size = btf_check_meta(env, t, end - cur);
+		if (meta_size < 0)
+			return meta_size;
+
+		btf_add_type(env, t);
+		cur += meta_size;
+		env->log_type_id++;
+	}
+
+	return 0;
+}
+
+static bool btf_resolve_valid(struct btf_verifier_env *env,
+			      const struct btf_type *t,
+			      u32 type_id)
+{
+	struct btf *btf = env->btf;
+
+	if (!env_type_is_resolved(env, type_id))
+		return false;
+
+	if (btf_type_is_struct(t) || btf_type_is_datasec(t))
+		return !btf_resolved_type_id(btf, type_id) &&
+		       !btf_resolved_type_size(btf, type_id);
+
+	if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
+		return btf_resolved_type_id(btf, type_id) &&
+		       !btf_resolved_type_size(btf, type_id);
+
+	if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
+	    btf_type_is_var(t)) {
+		t = btf_type_id_resolve(btf, &type_id);
+		return t &&
+		       !btf_type_is_modifier(t) &&
+		       !btf_type_is_var(t) &&
+		       !btf_type_is_datasec(t);
+	}
+
+	if (btf_type_is_array(t)) {
+		const struct btf_array *array = btf_type_array(t);
+		const struct btf_type *elem_type;
+		u32 elem_type_id = array->type;
+		u32 elem_size;
+
+		elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
+		return elem_type && !btf_type_is_modifier(elem_type) &&
+			(array->nelems * elem_size ==
+			 btf_resolved_type_size(btf, type_id));
+	}
+
+	return false;
+}
+
+static int btf_resolve(struct btf_verifier_env *env,
+		       const struct btf_type *t, u32 type_id)
+{
+	u32 save_log_type_id = env->log_type_id;
+	const struct resolve_vertex *v;
+	int err = 0;
+
+	env->resolve_mode = RESOLVE_TBD;
+	env_stack_push(env, t, type_id);
+	while (!err && (v = env_stack_peak(env))) {
+		env->log_type_id = v->type_id;
+		err = btf_type_ops(v->t)->resolve(env, v);
+	}
+
+	env->log_type_id = type_id;
+	if (err == -E2BIG) {
+		btf_verifier_log_type(env, t,
+				      "Exceeded max resolving depth:%u",
+				      MAX_RESOLVE_DEPTH);
+	} else if (err == -EEXIST) {
+		btf_verifier_log_type(env, t, "Loop detected");
+	}
+
+	/* Final sanity check */
+	if (!err && !btf_resolve_valid(env, t, type_id)) {
+		btf_verifier_log_type(env, t, "Invalid resolve state");
+		err = -EINVAL;
+	}
+
+	env->log_type_id = save_log_type_id;
+	return err;
+}
+
+static int btf_check_all_types(struct btf_verifier_env *env)
+{
+	struct btf *btf = env->btf;
+	const struct btf_type *t;
+	u32 type_id, i;
+	int err;
+
+	err = env_resolve_init(env);
+	if (err)
+		return err;
+
+	env->phase++;
+	for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
+		type_id = btf->start_id + i;
+		t = btf_type_by_id(btf, type_id);
+
+		env->log_type_id = type_id;
+		if (btf_type_needs_resolve(t) &&
+		    !env_type_is_resolved(env, type_id)) {
+			err = btf_resolve(env, t, type_id);
+			if (err)
+				return err;
+		}
+
+		if (btf_type_is_func_proto(t)) {
+			err = btf_func_proto_check(env, t);
+			if (err)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+static int btf_parse_type_sec(struct btf_verifier_env *env)
+{
+	const struct btf_header *hdr = &env->btf->hdr;
+	int err;
+
+	/* Type section must align to 4 bytes */
+	if (hdr->type_off & (sizeof(u32) - 1)) {
+		btf_verifier_log(env, "Unaligned type_off");
+		return -EINVAL;
+	}
+
+	if (!env->btf->base_btf && !hdr->type_len) {
+		btf_verifier_log(env, "No type found");
+		return -EINVAL;
+	}
+
+	err = btf_check_all_metas(env);
+	if (err)
+		return err;
+
+	return btf_check_all_types(env);
+}
+
+static int btf_parse_str_sec(struct btf_verifier_env *env)
+{
+	const struct btf_header *hdr;
+	struct btf *btf = env->btf;
+	const char *start, *end;
+
+	hdr = &btf->hdr;
+	start = btf->nohdr_data + hdr->str_off;
+	end = start + hdr->str_len;
+
+	if (end != btf->data + btf->data_size) {
+		btf_verifier_log(env, "String section is not at the end");
+		return -EINVAL;
+	}
+
+	btf->strings = start;
+
+	if (btf->base_btf && !hdr->str_len)
+		return 0;
+	if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
+		btf_verifier_log(env, "Invalid string section");
+		return -EINVAL;
+	}
+	if (!btf->base_btf && start[0]) {
+		btf_verifier_log(env, "Invalid string section");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const size_t btf_sec_info_offset[] = {
+	offsetof(struct btf_header, type_off),
+	offsetof(struct btf_header, str_off),
+};
+
+static int btf_sec_info_cmp(const void *a, const void *b)
+{
+	const struct btf_sec_info *x = a;
+	const struct btf_sec_info *y = b;
+
+	return (int)(x->off - y->off) ? : (int)(x->len - y->len);
+}
+
+static int btf_check_sec_info(struct btf_verifier_env *env,
+			      u32 btf_data_size)
+{
+	struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
+	u32 total, expected_total, i;
+	const struct btf_header *hdr;
+	const struct btf *btf;
+
+	btf = env->btf;
+	hdr = &btf->hdr;
+
+	/* Populate the secs from hdr */
+	for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
+		secs[i] = *(struct btf_sec_info *)((void *)hdr +
+						   btf_sec_info_offset[i]);
+
+	sort(secs, ARRAY_SIZE(btf_sec_info_offset),
+	     sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
+
+	/* Check for gaps and overlap among sections */
+	total = 0;
+	expected_total = btf_data_size - hdr->hdr_len;
+	for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
+		if (expected_total < secs[i].off) {
+			btf_verifier_log(env, "Invalid section offset");
+			return -EINVAL;
+		}
+		if (total < secs[i].off) {
+			/* gap */
+			btf_verifier_log(env, "Unsupported section found");
+			return -EINVAL;
+		}
+		if (total > secs[i].off) {
+			btf_verifier_log(env, "Section overlap found");
+			return -EINVAL;
+		}
+		if (expected_total - total < secs[i].len) {
+			btf_verifier_log(env,
+					 "Total section length too long");
+			return -EINVAL;
+		}
+		total += secs[i].len;
+	}
+
+	/* There is data other than hdr and known sections */
+	if (expected_total != total) {
+		btf_verifier_log(env, "Unsupported section found");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int btf_parse_hdr(struct btf_verifier_env *env)
+{
+	u32 hdr_len, hdr_copy, btf_data_size;
+	const struct btf_header *hdr;
+	struct btf *btf;
+
+	btf = env->btf;
+	btf_data_size = btf->data_size;
+
+	if (btf_data_size < offsetofend(struct btf_header, hdr_len)) {
+		btf_verifier_log(env, "hdr_len not found");
+		return -EINVAL;
+	}
+
+	hdr = btf->data;
+	hdr_len = hdr->hdr_len;
+	if (btf_data_size < hdr_len) {
+		btf_verifier_log(env, "btf_header not found");
+		return -EINVAL;
+	}
+
+	/* Ensure the unsupported header fields are zero */
+	if (hdr_len > sizeof(btf->hdr)) {
+		u8 *expected_zero = btf->data + sizeof(btf->hdr);
+		u8 *end = btf->data + hdr_len;
+
+		for (; expected_zero < end; expected_zero++) {
+			if (*expected_zero) {
+				btf_verifier_log(env, "Unsupported btf_header");
+				return -E2BIG;
+			}
+		}
+	}
+
+	hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
+	memcpy(&btf->hdr, btf->data, hdr_copy);
+
+	hdr = &btf->hdr;
+
+	btf_verifier_log_hdr(env, btf_data_size);
+
+	if (hdr->magic != BTF_MAGIC) {
+		btf_verifier_log(env, "Invalid magic");
+		return -EINVAL;
+	}
+
+	if (hdr->version != BTF_VERSION) {
+		btf_verifier_log(env, "Unsupported version");
+		return -ENOTSUPP;
+	}
+
+	if (hdr->flags) {
+		btf_verifier_log(env, "Unsupported flags");
+		return -ENOTSUPP;
+	}
+
+	if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
+		btf_verifier_log(env, "No data");
+		return -EINVAL;
+	}
+
+	return btf_check_sec_info(env, btf_data_size);
+}
+
+static int btf_check_type_tags(struct btf_verifier_env *env,
+			       struct btf *btf, int start_id)
+{
+	int i, n, good_id = start_id - 1;
+	bool in_tags;
+
+	n = btf_nr_types(btf);
+	for (i = start_id; i < n; i++) {
+		const struct btf_type *t;
+		int chain_limit = 32;
+		u32 cur_id = i;
+
+		t = btf_type_by_id(btf, i);
+		if (!t)
+			return -EINVAL;
+		if (!btf_type_is_modifier(t))
+			continue;
+
+		cond_resched();
+
+		in_tags = btf_type_is_type_tag(t);
+		while (btf_type_is_modifier(t)) {
+			if (!chain_limit--) {
+				btf_verifier_log(env, "Max chain length or cycle detected");
+				return -ELOOP;
+			}
+			if (btf_type_is_type_tag(t)) {
+				if (!in_tags) {
+					btf_verifier_log(env, "Type tags don't precede modifiers");
+					return -EINVAL;
+				}
+			} else if (in_tags) {
+				in_tags = false;
+			}
+			if (cur_id <= good_id)
+				break;
+			/* Move to next type */
+			cur_id = t->type;
+			t = btf_type_by_id(btf, cur_id);
+			if (!t)
+				return -EINVAL;
+		}
+		good_id = i;
+	}
+	return 0;
+}
+
+static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
+			     u32 log_level, char __user *log_ubuf, u32 log_size)
+{
+	struct btf_verifier_env *env = NULL;
+	struct bpf_verifier_log *log;
+	struct btf *btf = NULL;
+	u8 *data;
+	int err;
+
+	if (btf_data_size > BTF_MAX_SIZE)
+		return ERR_PTR(-E2BIG);
+
+	env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
+	if (!env)
+		return ERR_PTR(-ENOMEM);
+
+	log = &env->log;
+	if (log_level || log_ubuf || log_size) {
+		/* user requested verbose verifier output
+		 * and supplied buffer to store the verification trace
+		 */
+		log->level = log_level;
+		log->ubuf = log_ubuf;
+		log->len_total = log_size;
+
+		/* log attributes have to be sane */
+		if (!bpf_verifier_log_attr_valid(log)) {
+			err = -EINVAL;
+			goto errout;
+		}
+	}
+
+	btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
+	if (!btf) {
+		err = -ENOMEM;
+		goto errout;
+	}
+	env->btf = btf;
+
+	data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
+	if (!data) {
+		err = -ENOMEM;
+		goto errout;
+	}
+
+	btf->data = data;
+	btf->data_size = btf_data_size;
+
+	if (copy_from_bpfptr(data, btf_data, btf_data_size)) {
+		err = -EFAULT;
+		goto errout;
+	}
+
+	err = btf_parse_hdr(env);
+	if (err)
+		goto errout;
+
+	btf->nohdr_data = btf->data + btf->hdr.hdr_len;
+
+	err = btf_parse_str_sec(env);
+	if (err)
+		goto errout;
+
+	err = btf_parse_type_sec(env);
+	if (err)
+		goto errout;
+
+	err = btf_check_type_tags(env, btf, 1);
+	if (err)
+		goto errout;
+
+	if (log->level && bpf_verifier_log_full(log)) {
+		err = -ENOSPC;
+		goto errout;
+	}
+
+	btf_verifier_env_free(env);
+	refcount_set(&btf->refcnt, 1);
+	return btf;
+
+errout:
+	btf_verifier_env_free(env);
+	if (btf)
+		btf_free(btf);
+	return ERR_PTR(err);
+}
+
+extern char __weak __start_BTF[];
+extern char __weak __stop_BTF[];
+extern struct btf *btf_vmlinux;
+
+#define BPF_MAP_TYPE(_id, _ops)
+#define BPF_LINK_TYPE(_id, _name)
+static union {
+	struct bpf_ctx_convert {
+#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
+	prog_ctx_type _id##_prog; \
+	kern_ctx_type _id##_kern;
+#include <linux/bpf_types.h>
+#undef BPF_PROG_TYPE
+	} *__t;
+	/* 't' is written once under lock. Read many times. */
+	const struct btf_type *t;
+} bpf_ctx_convert;
+enum {
+#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
+	__ctx_convert##_id,
+#include <linux/bpf_types.h>
+#undef BPF_PROG_TYPE
+	__ctx_convert_unused, /* to avoid empty enum in extreme .config */
+};
+static u8 bpf_ctx_convert_map[] = {
+#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
+	[_id] = __ctx_convert##_id,
+#include <linux/bpf_types.h>
+#undef BPF_PROG_TYPE
+	0, /* avoid empty array */
+};
+#undef BPF_MAP_TYPE
+#undef BPF_LINK_TYPE
+
+static const struct btf_member *
+btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
+		      const struct btf_type *t, enum bpf_prog_type prog_type,
+		      int arg)
+{
+	const struct btf_type *conv_struct;
+	const struct btf_type *ctx_struct;
+	const struct btf_member *ctx_type;
+	const char *tname, *ctx_tname;
+
+	conv_struct = bpf_ctx_convert.t;
+	if (!conv_struct) {
+		bpf_log(log, "btf_vmlinux is malformed\n");
+		return NULL;
+	}
+	t = btf_type_by_id(btf, t->type);
+	while (btf_type_is_modifier(t))
+		t = btf_type_by_id(btf, t->type);
+	if (!btf_type_is_struct(t)) {
+		/* Only pointer to struct is supported for now.
+		 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
+		 * is not supported yet.
+		 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
+		 */
+		return NULL;
+	}
+	tname = btf_name_by_offset(btf, t->name_off);
+	if (!tname) {
+		bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
+		return NULL;
+	}
+	/* prog_type is valid bpf program type. No need for bounds check. */
+	ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
+	/* ctx_struct is a pointer to prog_ctx_type in vmlinux.
+	 * Like 'struct __sk_buff'
+	 */
+	ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type);
+	if (!ctx_struct)
+		/* should not happen */
+		return NULL;
+again:
+	ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off);
+	if (!ctx_tname) {
+		/* should not happen */
+		bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
+		return NULL;
+	}
+	/* only compare that prog's ctx type name is the same as
+	 * kernel expects. No need to compare field by field.
+	 * It's ok for bpf prog to do:
+	 * struct __sk_buff {};
+	 * int socket_filter_bpf_prog(struct __sk_buff *skb)
+	 * { // no fields of skb are ever used }
+	 */
+	if (strcmp(ctx_tname, tname)) {
+		/* bpf_user_pt_regs_t is a typedef, so resolve it to
+		 * underlying struct and check name again
+		 */
+		if (!btf_type_is_modifier(ctx_struct))
+			return NULL;
+		while (btf_type_is_modifier(ctx_struct))
+			ctx_struct = btf_type_by_id(btf_vmlinux, ctx_struct->type);
+		goto again;
+	}
+	return ctx_type;
+}
+
+static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
+				     struct btf *btf,
+				     const struct btf_type *t,
+				     enum bpf_prog_type prog_type,
+				     int arg)
+{
+	const struct btf_member *prog_ctx_type, *kern_ctx_type;
+
+	prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type, arg);
+	if (!prog_ctx_type)
+		return -ENOENT;
+	kern_ctx_type = prog_ctx_type + 1;
+	return kern_ctx_type->type;
+}
+
+BTF_ID_LIST(bpf_ctx_convert_btf_id)
+BTF_ID(struct, bpf_ctx_convert)
+
+struct btf *btf_parse_vmlinux(void)
+{
+	struct btf_verifier_env *env = NULL;
+	struct bpf_verifier_log *log;
+	struct btf *btf = NULL;
+	int err;
+
+	env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
+	if (!env)
+		return ERR_PTR(-ENOMEM);
+
+	log = &env->log;
+	log->level = BPF_LOG_KERNEL;
+
+	btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
+	if (!btf) {
+		err = -ENOMEM;
+		goto errout;
+	}
+	env->btf = btf;
+
+	btf->data = __start_BTF;
+	btf->data_size = __stop_BTF - __start_BTF;
+	btf->kernel_btf = true;
+	snprintf(btf->name, sizeof(btf->name), "vmlinux");
+
+	err = btf_parse_hdr(env);
+	if (err)
+		goto errout;
+
+	btf->nohdr_data = btf->data + btf->hdr.hdr_len;
+
+	err = btf_parse_str_sec(env);
+	if (err)
+		goto errout;
+
+	err = btf_check_all_metas(env);
+	if (err)
+		goto errout;
+
+	err = btf_check_type_tags(env, btf, 1);
+	if (err)
+		goto errout;
+
+	/* btf_parse_vmlinux() runs under bpf_verifier_lock */
+	bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
+
+	bpf_struct_ops_init(btf, log);
+
+	refcount_set(&btf->refcnt, 1);
+
+	err = btf_alloc_id(btf);
+	if (err)
+		goto errout;
+
+	btf_verifier_env_free(env);
+	return btf;
+
+errout:
+	btf_verifier_env_free(env);
+	if (btf) {
+		kvfree(btf->types);
+		kfree(btf);
+	}
+	return ERR_PTR(err);
+}
+
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+
+static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
+{
+	struct btf_verifier_env *env = NULL;
+	struct bpf_verifier_log *log;
+	struct btf *btf = NULL, *base_btf;
+	int err;
+
+	base_btf = bpf_get_btf_vmlinux();
+	if (IS_ERR(base_btf))
+		return base_btf;
+	if (!base_btf)
+		return ERR_PTR(-EINVAL);
+
+	env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
+	if (!env)
+		return ERR_PTR(-ENOMEM);
+
+	log = &env->log;
+	log->level = BPF_LOG_KERNEL;
+
+	btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
+	if (!btf) {
+		err = -ENOMEM;
+		goto errout;
+	}
+	env->btf = btf;
+
+	btf->base_btf = base_btf;
+	btf->start_id = base_btf->nr_types;
+	btf->start_str_off = base_btf->hdr.str_len;
+	btf->kernel_btf = true;
+	snprintf(btf->name, sizeof(btf->name), "%s", module_name);
+
+	btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
+	if (!btf->data) {
+		err = -ENOMEM;
+		goto errout;
+	}
+	memcpy(btf->data, data, data_size);
+	btf->data_size = data_size;
+
+	err = btf_parse_hdr(env);
+	if (err)
+		goto errout;
+
+	btf->nohdr_data = btf->data + btf->hdr.hdr_len;
+
+	err = btf_parse_str_sec(env);
+	if (err)
+		goto errout;
+
+	err = btf_check_all_metas(env);
+	if (err)
+		goto errout;
+
+	err = btf_check_type_tags(env, btf, btf_nr_types(base_btf));
+	if (err)
+		goto errout;
+
+	btf_verifier_env_free(env);
+	refcount_set(&btf->refcnt, 1);
+	return btf;
+
+errout:
+	btf_verifier_env_free(env);
+	if (btf) {
+		kvfree(btf->data);
+		kvfree(btf->types);
+		kfree(btf);
+	}
+	return ERR_PTR(err);
+}
+
+#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
+
+struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
+{
+	struct bpf_prog *tgt_prog = prog->aux->dst_prog;
+
+	if (tgt_prog)
+		return tgt_prog->aux->btf;
+	else
+		return prog->aux->attach_btf;
+}
+
+static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
+{
+	/* skip modifiers */
+	t = btf_type_skip_modifiers(btf, t->type, NULL);
+
+	return btf_type_is_int(t);
+}
+
+static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto,
+			   int off)
+{
+	const struct btf_param *args;
+	const struct btf_type *t;
+	u32 offset = 0, nr_args;
+	int i;
+
+	if (!func_proto)
+		return off / 8;
+
+	nr_args = btf_type_vlen(func_proto);
+	args = (const struct btf_param *)(func_proto + 1);
+	for (i = 0; i < nr_args; i++) {
+		t = btf_type_skip_modifiers(btf, args[i].type, NULL);
+		offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
+		if (off < offset)
+			return i;
+	}
+
+	t = btf_type_skip_modifiers(btf, func_proto->type, NULL);
+	offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
+	if (off < offset)
+		return nr_args;
+
+	return nr_args + 1;
+}
+
+bool btf_ctx_access(int off, int size, enum bpf_access_type type,
+		    const struct bpf_prog *prog,
+		    struct bpf_insn_access_aux *info)
+{
+	const struct btf_type *t = prog->aux->attach_func_proto;
+	struct bpf_prog *tgt_prog = prog->aux->dst_prog;
+	struct btf *btf = bpf_prog_get_target_btf(prog);
+	const char *tname = prog->aux->attach_func_name;
+	struct bpf_verifier_log *log = info->log;
+	const struct btf_param *args;
+	const char *tag_value;
+	u32 nr_args, arg;
+	int i, ret;
+
+	if (off % 8) {
+		bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
+			tname, off);
+		return false;
+	}
+	arg = get_ctx_arg_idx(btf, t, off);
+	args = (const struct btf_param *)(t + 1);
+	/* if (t == NULL) Fall back to default BPF prog with
+	 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
+	 */
+	nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
+	if (prog->aux->attach_btf_trace) {
+		/* skip first 'void *__data' argument in btf_trace_##name typedef */
+		args++;
+		nr_args--;
+	}
+
+	if (arg > nr_args) {
+		bpf_log(log, "func '%s' doesn't have %d-th argument\n",
+			tname, arg + 1);
+		return false;
+	}
+
+	if (arg == nr_args) {
+		switch (prog->expected_attach_type) {
+		case BPF_LSM_CGROUP:
+		case BPF_LSM_MAC:
+		case BPF_TRACE_FEXIT:
+			/* When LSM programs are attached to void LSM hooks
+			 * they use FEXIT trampolines and when attached to
+			 * int LSM hooks, they use MODIFY_RETURN trampolines.
+			 *
+			 * While the LSM programs are BPF_MODIFY_RETURN-like
+			 * the check:
+			 *
+			 *	if (ret_type != 'int')
+			 *		return -EINVAL;
+			 *
+			 * is _not_ done here. This is still safe as LSM hooks
+			 * have only void and int return types.
+			 */
+			if (!t)
+				return true;
+			t = btf_type_by_id(btf, t->type);
+			break;
+		case BPF_MODIFY_RETURN:
+			/* For now the BPF_MODIFY_RETURN can only be attached to
+			 * functions that return an int.
+			 */
+			if (!t)
+				return false;
+
+			t = btf_type_skip_modifiers(btf, t->type, NULL);
+			if (!btf_type_is_small_int(t)) {
+				bpf_log(log,
+					"ret type %s not allowed for fmod_ret\n",
+					btf_type_str(t));
+				return false;
+			}
+			break;
+		default:
+			bpf_log(log, "func '%s' doesn't have %d-th argument\n",
+				tname, arg + 1);
+			return false;
+		}
+	} else {
+		if (!t)
+			/* Default prog with MAX_BPF_FUNC_REG_ARGS args */
+			return true;
+		t = btf_type_by_id(btf, args[arg].type);
+	}
+
+	/* skip modifiers */
+	while (btf_type_is_modifier(t))
+		t = btf_type_by_id(btf, t->type);
+	if (btf_type_is_small_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
+		/* accessing a scalar */
+		return true;
+	if (!btf_type_is_ptr(t)) {
+		bpf_log(log,
+			"func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
+			tname, arg,
+			__btf_name_by_offset(btf, t->name_off),
+			btf_type_str(t));
+		return false;
+	}
+
+	/* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
+	for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
+		const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
+		u32 type, flag;
+
+		type = base_type(ctx_arg_info->reg_type);
+		flag = type_flag(ctx_arg_info->reg_type);
+		if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
+		    (flag & PTR_MAYBE_NULL)) {
+			info->reg_type = ctx_arg_info->reg_type;
+			return true;
+		}
+	}
+
+	if (t->type == 0)
+		/* This is a pointer to void.
+		 * It is the same as scalar from the verifier safety pov.
+		 * No further pointer walking is allowed.
+		 */
+		return true;
+
+	if (is_int_ptr(btf, t))
+		return true;
+
+	/* this is a pointer to another type */
+	for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
+		const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
+
+		if (ctx_arg_info->offset == off) {
+			if (!ctx_arg_info->btf_id) {
+				bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
+				return false;
+			}
+
+			info->reg_type = ctx_arg_info->reg_type;
+			info->btf = btf_vmlinux;
+			info->btf_id = ctx_arg_info->btf_id;
+			return true;
+		}
+	}
+
+	info->reg_type = PTR_TO_BTF_ID;
+	if (tgt_prog) {
+		enum bpf_prog_type tgt_type;
+
+		if (tgt_prog->type == BPF_PROG_TYPE_EXT)
+			tgt_type = tgt_prog->aux->saved_dst_prog_type;
+		else
+			tgt_type = tgt_prog->type;
+
+		ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
+		if (ret > 0) {
+			info->btf = btf_vmlinux;
+			info->btf_id = ret;
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	info->btf = btf;
+	info->btf_id = t->type;
+	t = btf_type_by_id(btf, t->type);
+
+	if (btf_type_is_type_tag(t)) {
+		tag_value = __btf_name_by_offset(btf, t->name_off);
+		if (strcmp(tag_value, "user") == 0)
+			info->reg_type |= MEM_USER;
+		if (strcmp(tag_value, "percpu") == 0)
+			info->reg_type |= MEM_PERCPU;
+	}
+
+	/* skip modifiers */
+	while (btf_type_is_modifier(t)) {
+		info->btf_id = t->type;
+		t = btf_type_by_id(btf, t->type);
+	}
+	if (!btf_type_is_struct(t)) {
+		bpf_log(log,
+			"func '%s' arg%d type %s is not a struct\n",
+			tname, arg, btf_type_str(t));
+		return false;
+	}
+	bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
+		tname, arg, info->btf_id, btf_type_str(t),
+		__btf_name_by_offset(btf, t->name_off));
+	return true;
+}
+
+enum bpf_struct_walk_result {
+	/* < 0 error */
+	WALK_SCALAR = 0,
+	WALK_PTR,
+	WALK_STRUCT,
+};
+
+static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
+			   const struct btf_type *t, int off, int size,
+			   u32 *next_btf_id, enum bpf_type_flag *flag)
+{
+	u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
+	const struct btf_type *mtype, *elem_type = NULL;
+	const struct btf_member *member;
+	const char *tname, *mname, *tag_value;
+	u32 vlen, elem_id, mid;
+
+again:
+	tname = __btf_name_by_offset(btf, t->name_off);
+	if (!btf_type_is_struct(t)) {
+		bpf_log(log, "Type '%s' is not a struct\n", tname);
+		return -EINVAL;
+	}
+
+	vlen = btf_type_vlen(t);
+	if (off + size > t->size) {
+		/* If the last element is a variable size array, we may
+		 * need to relax the rule.
+		 */
+		struct btf_array *array_elem;
+
+		if (vlen == 0)
+			goto error;
+
+		member = btf_type_member(t) + vlen - 1;
+		mtype = btf_type_skip_modifiers(btf, member->type,
+						NULL);
+		if (!btf_type_is_array(mtype))
+			goto error;
+
+		array_elem = (struct btf_array *)(mtype + 1);
+		if (array_elem->nelems != 0)
+			goto error;
+
+		moff = __btf_member_bit_offset(t, member) / 8;
+		if (off < moff)
+			goto error;
+
+		/* Only allow structure for now, can be relaxed for
+		 * other types later.
+		 */
+		t = btf_type_skip_modifiers(btf, array_elem->type,
+					    NULL);
+		if (!btf_type_is_struct(t))
+			goto error;
+
+		off = (off - moff) % t->size;
+		goto again;
+
+error:
+		bpf_log(log, "access beyond struct %s at off %u size %u\n",
+			tname, off, size);
+		return -EACCES;
+	}
+
+	for_each_member(i, t, member) {
+		/* offset of the field in bytes */
+		moff = __btf_member_bit_offset(t, member) / 8;
+		if (off + size <= moff)
+			/* won't find anything, field is already too far */
+			break;
+
+		if (__btf_member_bitfield_size(t, member)) {
+			u32 end_bit = __btf_member_bit_offset(t, member) +
+				__btf_member_bitfield_size(t, member);
+
+			/* off <= moff instead of off == moff because clang
+			 * does not generate a BTF member for anonymous
+			 * bitfield like the ":16" here:
+			 * struct {
+			 *	int :16;
+			 *	int x:8;
+			 * };
+			 */
+			if (off <= moff &&
+			    BITS_ROUNDUP_BYTES(end_bit) <= off + size)
+				return WALK_SCALAR;
+
+			/* off may be accessing a following member
+			 *
+			 * or
+			 *
+			 * Doing partial access at either end of this
+			 * bitfield.  Continue on this case also to
+			 * treat it as not accessing this bitfield
+			 * and eventually error out as field not
+			 * found to keep it simple.
+			 * It could be relaxed if there was a legit
+			 * partial access case later.
+			 */
+			continue;
+		}
+
+		/* In case of "off" is pointing to holes of a struct */
+		if (off < moff)
+			break;
+
+		/* type of the field */
+		mid = member->type;
+		mtype = btf_type_by_id(btf, member->type);
+		mname = __btf_name_by_offset(btf, member->name_off);
+
+		mtype = __btf_resolve_size(btf, mtype, &msize,
+					   &elem_type, &elem_id, &total_nelems,
+					   &mid);
+		if (IS_ERR(mtype)) {
+			bpf_log(log, "field %s doesn't have size\n", mname);
+			return -EFAULT;
+		}
+
+		mtrue_end = moff + msize;
+		if (off >= mtrue_end)
+			/* no overlap with member, keep iterating */
+			continue;
+
+		if (btf_type_is_array(mtype)) {
+			u32 elem_idx;
+
+			/* __btf_resolve_size() above helps to
+			 * linearize a multi-dimensional array.
+			 *
+			 * The logic here is treating an array
+			 * in a struct as the following way:
+			 *
+			 * struct outer {
+			 *	struct inner array[2][2];
+			 * };
+			 *
+			 * looks like:
+			 *
+			 * struct outer {
+			 *	struct inner array_elem0;
+			 *	struct inner array_elem1;
+			 *	struct inner array_elem2;
+			 *	struct inner array_elem3;
+			 * };
+			 *
+			 * When accessing outer->array[1][0], it moves
+			 * moff to "array_elem2", set mtype to
+			 * "struct inner", and msize also becomes
+			 * sizeof(struct inner).  Then most of the
+			 * remaining logic will fall through without
+			 * caring the current member is an array or
+			 * not.
+			 *
+			 * Unlike mtype/msize/moff, mtrue_end does not
+			 * change.  The naming difference ("_true") tells
+			 * that it is not always corresponding to
+			 * the current mtype/msize/moff.
+			 * It is the true end of the current
+			 * member (i.e. array in this case).  That
+			 * will allow an int array to be accessed like
+			 * a scratch space,
+			 * i.e. allow access beyond the size of
+			 *      the array's element as long as it is
+			 *      within the mtrue_end boundary.
+			 */
+
+			/* skip empty array */
+			if (moff == mtrue_end)
+				continue;
+
+			msize /= total_nelems;
+			elem_idx = (off - moff) / msize;
+			moff += elem_idx * msize;
+			mtype = elem_type;
+			mid = elem_id;
+		}
+
+		/* the 'off' we're looking for is either equal to start
+		 * of this field or inside of this struct
+		 */
+		if (btf_type_is_struct(mtype)) {
+			/* our field must be inside that union or struct */
+			t = mtype;
+
+			/* return if the offset matches the member offset */
+			if (off == moff) {
+				*next_btf_id = mid;
+				return WALK_STRUCT;
+			}
+
+			/* adjust offset we're looking for */
+			off -= moff;
+			goto again;
+		}
+
+		if (btf_type_is_ptr(mtype)) {
+			const struct btf_type *stype, *t;
+			enum bpf_type_flag tmp_flag = 0;
+			u32 id;
+
+			if (msize != size || off != moff) {
+				bpf_log(log,
+					"cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
+					mname, moff, tname, off, size);
+				return -EACCES;
+			}
+
+			/* check type tag */
+			t = btf_type_by_id(btf, mtype->type);
+			if (btf_type_is_type_tag(t)) {
+				tag_value = __btf_name_by_offset(btf, t->name_off);
+				/* check __user tag */
+				if (strcmp(tag_value, "user") == 0)
+					tmp_flag = MEM_USER;
+				/* check __percpu tag */
+				if (strcmp(tag_value, "percpu") == 0)
+					tmp_flag = MEM_PERCPU;
+			}
+
+			stype = btf_type_skip_modifiers(btf, mtype->type, &id);
+			if (btf_type_is_struct(stype)) {
+				*next_btf_id = id;
+				*flag = tmp_flag;
+				return WALK_PTR;
+			}
+		}
+
+		/* Allow more flexible access within an int as long as
+		 * it is within mtrue_end.
+		 * Since mtrue_end could be the end of an array,
+		 * that also allows using an array of int as a scratch
+		 * space. e.g. skb->cb[].
+		 */
+		if (off + size > mtrue_end && !(*flag & PTR_UNTRUSTED)) {
+			bpf_log(log,
+				"access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
+				mname, mtrue_end, tname, off, size);
+			return -EACCES;
+		}
+
+		return WALK_SCALAR;
+	}
+	bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
+	return -EINVAL;
+}
+
+int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
+		      const struct btf_type *t, int off, int size,
+		      enum bpf_access_type atype __maybe_unused,
+		      u32 *next_btf_id, enum bpf_type_flag *flag)
+{
+	enum bpf_type_flag tmp_flag = 0;
+	int err;
+	u32 id;
+
+	do {
+		err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag);
+
+		switch (err) {
+		case WALK_PTR:
+			/* If we found the pointer or scalar on t+off,
+			 * we're done.
+			 */
+			*next_btf_id = id;
+			*flag = tmp_flag;
+			return PTR_TO_BTF_ID;
+		case WALK_SCALAR:
+			return SCALAR_VALUE;
+		case WALK_STRUCT:
+			/* We found nested struct, so continue the search
+			 * by diving in it. At this point the offset is
+			 * aligned with the new type, so set it to 0.
+			 */
+			t = btf_type_by_id(btf, id);
+			off = 0;
+			break;
+		default:
+			/* It's either error or unknown return value..
+			 * scream and leave.
+			 */
+			if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
+				return -EINVAL;
+			return err;
+		}
+	} while (t);
+
+	return -EINVAL;
+}
+
+/* Check that two BTF types, each specified as an BTF object + id, are exactly
+ * the same. Trivial ID check is not enough due to module BTFs, because we can
+ * end up with two different module BTFs, but IDs point to the common type in
+ * vmlinux BTF.
+ */
+static bool btf_types_are_same(const struct btf *btf1, u32 id1,
+			       const struct btf *btf2, u32 id2)
+{
+	if (id1 != id2)
+		return false;
+	if (btf1 == btf2)
+		return true;
+	return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
+}
+
+bool btf_struct_ids_match(struct bpf_verifier_log *log,
+			  const struct btf *btf, u32 id, int off,
+			  const struct btf *need_btf, u32 need_type_id,
+			  bool strict)
+{
+	const struct btf_type *type;
+	enum bpf_type_flag flag;
+	int err;
+
+	/* Are we already done? */
+	if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
+		return true;
+	/* In case of strict type match, we do not walk struct, the top level
+	 * type match must succeed. When strict is true, off should have already
+	 * been 0.
+	 */
+	if (strict)
+		return false;
+again:
+	type = btf_type_by_id(btf, id);
+	if (!type)
+		return false;
+	err = btf_struct_walk(log, btf, type, off, 1, &id, &flag);
+	if (err != WALK_STRUCT)
+		return false;
+
+	/* We found nested struct object. If it matches
+	 * the requested ID, we're done. Otherwise let's
+	 * continue the search with offset 0 in the new
+	 * type.
+	 */
+	if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
+		off = 0;
+		goto again;
+	}
+
+	return true;
+}
+
+static int __get_type_size(struct btf *btf, u32 btf_id,
+			   const struct btf_type **ret_type)
+{
+	const struct btf_type *t;
+
+	*ret_type = btf_type_by_id(btf, 0);
+	if (!btf_id)
+		/* void */
+		return 0;
+	t = btf_type_by_id(btf, btf_id);
+	while (t && btf_type_is_modifier(t))
+		t = btf_type_by_id(btf, t->type);
+	if (!t)
+		return -EINVAL;
+	*ret_type = t;
+	if (btf_type_is_ptr(t))
+		/* kernel size of pointer. Not BPF's size of pointer*/
+		return sizeof(void *);
+	if (btf_type_is_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
+		return t->size;
+	return -EINVAL;
+}
+
+int btf_distill_func_proto(struct bpf_verifier_log *log,
+			   struct btf *btf,
+			   const struct btf_type *func,
+			   const char *tname,
+			   struct btf_func_model *m)
+{
+	const struct btf_param *args;
+	const struct btf_type *t;
+	u32 i, nargs;
+	int ret;
+
+	if (!func) {
+		/* BTF function prototype doesn't match the verifier types.
+		 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
+		 */
+		for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
+			m->arg_size[i] = 8;
+			m->arg_flags[i] = 0;
+		}
+		m->ret_size = 8;
+		m->nr_args = MAX_BPF_FUNC_REG_ARGS;
+		return 0;
+	}
+	args = (const struct btf_param *)(func + 1);
+	nargs = btf_type_vlen(func);
+	if (nargs > MAX_BPF_FUNC_ARGS) {
+		bpf_log(log,
+			"The function %s has %d arguments. Too many.\n",
+			tname, nargs);
+		return -EINVAL;
+	}
+	ret = __get_type_size(btf, func->type, &t);
+	if (ret < 0 || __btf_type_is_struct(t)) {
+		bpf_log(log,
+			"The function %s return type %s is unsupported.\n",
+			tname, btf_type_str(t));
+		return -EINVAL;
+	}
+	m->ret_size = ret;
+
+	for (i = 0; i < nargs; i++) {
+		if (i == nargs - 1 && args[i].type == 0) {
+			bpf_log(log,
+				"The function %s with variable args is unsupported.\n",
+				tname);
+			return -EINVAL;
+		}
+		ret = __get_type_size(btf, args[i].type, &t);
+
+		/* No support of struct argument size greater than 16 bytes */
+		if (ret < 0 || ret > 16) {
+			bpf_log(log,
+				"The function %s arg%d type %s is unsupported.\n",
+				tname, i, btf_type_str(t));
+			return -EINVAL;
+		}
+		if (ret == 0) {
+			bpf_log(log,
+				"The function %s has malformed void argument.\n",
+				tname);
+			return -EINVAL;
+		}
+		m->arg_size[i] = ret;
+		m->arg_flags[i] = __btf_type_is_struct(t) ? BTF_FMODEL_STRUCT_ARG : 0;
+	}
+	m->nr_args = nargs;
+	return 0;
+}
+
+/* Compare BTFs of two functions assuming only scalars and pointers to context.
+ * t1 points to BTF_KIND_FUNC in btf1
+ * t2 points to BTF_KIND_FUNC in btf2
+ * Returns:
+ * EINVAL - function prototype mismatch
+ * EFAULT - verifier bug
+ * 0 - 99% match. The last 1% is validated by the verifier.
+ */
+static int btf_check_func_type_match(struct bpf_verifier_log *log,
+				     struct btf *btf1, const struct btf_type *t1,
+				     struct btf *btf2, const struct btf_type *t2)
+{
+	const struct btf_param *args1, *args2;
+	const char *fn1, *fn2, *s1, *s2;
+	u32 nargs1, nargs2, i;
+
+	fn1 = btf_name_by_offset(btf1, t1->name_off);
+	fn2 = btf_name_by_offset(btf2, t2->name_off);
+
+	if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
+		bpf_log(log, "%s() is not a global function\n", fn1);
+		return -EINVAL;
+	}
+	if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
+		bpf_log(log, "%s() is not a global function\n", fn2);
+		return -EINVAL;
+	}
+
+	t1 = btf_type_by_id(btf1, t1->type);
+	if (!t1 || !btf_type_is_func_proto(t1))
+		return -EFAULT;
+	t2 = btf_type_by_id(btf2, t2->type);
+	if (!t2 || !btf_type_is_func_proto(t2))
+		return -EFAULT;
+
+	args1 = (const struct btf_param *)(t1 + 1);
+	nargs1 = btf_type_vlen(t1);
+	args2 = (const struct btf_param *)(t2 + 1);
+	nargs2 = btf_type_vlen(t2);
+
+	if (nargs1 != nargs2) {
+		bpf_log(log, "%s() has %d args while %s() has %d args\n",
+			fn1, nargs1, fn2, nargs2);
+		return -EINVAL;
+	}
+
+	t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
+	t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
+	if (t1->info != t2->info) {
+		bpf_log(log,
+			"Return type %s of %s() doesn't match type %s of %s()\n",
+			btf_type_str(t1), fn1,
+			btf_type_str(t2), fn2);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < nargs1; i++) {
+		t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
+		t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
+
+		if (t1->info != t2->info) {
+			bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
+				i, fn1, btf_type_str(t1),
+				fn2, btf_type_str(t2));
+			return -EINVAL;
+		}
+		if (btf_type_has_size(t1) && t1->size != t2->size) {
+			bpf_log(log,
+				"arg%d in %s() has size %d while %s() has %d\n",
+				i, fn1, t1->size,
+				fn2, t2->size);
+			return -EINVAL;
+		}
+
+		/* global functions are validated with scalars and pointers
+		 * to context only. And only global functions can be replaced.
+		 * Hence type check only those types.
+		 */
+		if (btf_type_is_int(t1) || btf_is_any_enum(t1))
+			continue;
+		if (!btf_type_is_ptr(t1)) {
+			bpf_log(log,
+				"arg%d in %s() has unrecognized type\n",
+				i, fn1);
+			return -EINVAL;
+		}
+		t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
+		t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
+		if (!btf_type_is_struct(t1)) {
+			bpf_log(log,
+				"arg%d in %s() is not a pointer to context\n",
+				i, fn1);
+			return -EINVAL;
+		}
+		if (!btf_type_is_struct(t2)) {
+			bpf_log(log,
+				"arg%d in %s() is not a pointer to context\n",
+				i, fn2);
+			return -EINVAL;
+		}
+		/* This is an optional check to make program writing easier.
+		 * Compare names of structs and report an error to the user.
+		 * btf_prepare_func_args() already checked that t2 struct
+		 * is a context type. btf_prepare_func_args() will check
+		 * later that t1 struct is a context type as well.
+		 */
+		s1 = btf_name_by_offset(btf1, t1->name_off);
+		s2 = btf_name_by_offset(btf2, t2->name_off);
+		if (strcmp(s1, s2)) {
+			bpf_log(log,
+				"arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
+				i, fn1, s1, fn2, s2);
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+/* Compare BTFs of given program with BTF of target program */
+int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
+			 struct btf *btf2, const struct btf_type *t2)
+{
+	struct btf *btf1 = prog->aux->btf;
+	const struct btf_type *t1;
+	u32 btf_id = 0;
+
+	if (!prog->aux->func_info) {
+		bpf_log(log, "Program extension requires BTF\n");
+		return -EINVAL;
+	}
+
+	btf_id = prog->aux->func_info[0].type_id;
+	if (!btf_id)
+		return -EFAULT;
+
+	t1 = btf_type_by_id(btf1, btf_id);
+	if (!t1 || !btf_type_is_func(t1))
+		return -EFAULT;
+
+	return btf_check_func_type_match(log, btf1, t1, btf2, t2);
+}
+
+static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
+#ifdef CONFIG_NET
+	[PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
+	[PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
+	[PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
+#endif
+};
+
+/* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
+static bool __btf_type_is_scalar_struct(struct bpf_verifier_log *log,
+					const struct btf *btf,
+					const struct btf_type *t, int rec)
+{
+	const struct btf_type *member_type;
+	const struct btf_member *member;
+	u32 i;
+
+	if (!btf_type_is_struct(t))
+		return false;
+
+	for_each_member(i, t, member) {
+		const struct btf_array *array;
+
+		member_type = btf_type_skip_modifiers(btf, member->type, NULL);
+		if (btf_type_is_struct(member_type)) {
+			if (rec >= 3) {
+				bpf_log(log, "max struct nesting depth exceeded\n");
+				return false;
+			}
+			if (!__btf_type_is_scalar_struct(log, btf, member_type, rec + 1))
+				return false;
+			continue;
+		}
+		if (btf_type_is_array(member_type)) {
+			array = btf_type_array(member_type);
+			if (!array->nelems)
+				return false;
+			member_type = btf_type_skip_modifiers(btf, array->type, NULL);
+			if (!btf_type_is_scalar(member_type))
+				return false;
+			continue;
+		}
+		if (!btf_type_is_scalar(member_type))
+			return false;
+	}
+	return true;
+}
+
+static bool is_kfunc_arg_mem_size(const struct btf *btf,
+				  const struct btf_param *arg,
+				  const struct bpf_reg_state *reg)
+{
+	int len, sfx_len = sizeof("__sz") - 1;
+	const struct btf_type *t;
+	const char *param_name;
+
+	t = btf_type_skip_modifiers(btf, arg->type, NULL);
+	if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
+		return false;
+
+	/* In the future, this can be ported to use BTF tagging */
+	param_name = btf_name_by_offset(btf, arg->name_off);
+	if (str_is_empty(param_name))
+		return false;
+	len = strlen(param_name);
+	if (len < sfx_len)
+		return false;
+	param_name += len - sfx_len;
+	if (strncmp(param_name, "__sz", sfx_len))
+		return false;
+
+	return true;
+}
+
+static bool btf_is_kfunc_arg_mem_size(const struct btf *btf,
+				      const struct btf_param *arg,
+				      const struct bpf_reg_state *reg,
+				      const char *name)
+{
+	int len, target_len = strlen(name);
+	const struct btf_type *t;
+	const char *param_name;
+
+	t = btf_type_skip_modifiers(btf, arg->type, NULL);
+	if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
+		return false;
+
+	param_name = btf_name_by_offset(btf, arg->name_off);
+	if (str_is_empty(param_name))
+		return false;
+	len = strlen(param_name);
+	if (len != target_len)
+		return false;
+	if (strcmp(param_name, name))
+		return false;
+
+	return true;
+}
+
+static int btf_check_func_arg_match(struct bpf_verifier_env *env,
+				    const struct btf *btf, u32 func_id,
+				    struct bpf_reg_state *regs,
+				    bool ptr_to_mem_ok,
+				    struct bpf_kfunc_arg_meta *kfunc_meta,
+				    bool processing_call)
+{
+	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
+	bool rel = false, kptr_get = false, trusted_args = false;
+	bool sleepable = false;
+	struct bpf_verifier_log *log = &env->log;
+	u32 i, nargs, ref_id, ref_obj_id = 0;
+	bool is_kfunc = btf_is_kernel(btf);
+	const char *func_name, *ref_tname;
+	const struct btf_type *t, *ref_t;
+	const struct btf_param *args;
+	int ref_regno = 0, ret;
+
+	t = btf_type_by_id(btf, func_id);
+	if (!t || !btf_type_is_func(t)) {
+		/* These checks were already done by the verifier while loading
+		 * struct bpf_func_info or in add_kfunc_call().
+		 */
+		bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n",
+			func_id);
+		return -EFAULT;
+	}
+	func_name = btf_name_by_offset(btf, t->name_off);
+
+	t = btf_type_by_id(btf, t->type);
+	if (!t || !btf_type_is_func_proto(t)) {
+		bpf_log(log, "Invalid BTF of func %s\n", func_name);
+		return -EFAULT;
+	}
+	args = (const struct btf_param *)(t + 1);
+	nargs = btf_type_vlen(t);
+	if (nargs > MAX_BPF_FUNC_REG_ARGS) {
+		bpf_log(log, "Function %s has %d > %d args\n", func_name, nargs,
+			MAX_BPF_FUNC_REG_ARGS);
+		return -EINVAL;
+	}
+
+	if (is_kfunc && kfunc_meta) {
+		/* Only kfunc can be release func */
+		rel = kfunc_meta->flags & KF_RELEASE;
+		kptr_get = kfunc_meta->flags & KF_KPTR_GET;
+		trusted_args = kfunc_meta->flags & KF_TRUSTED_ARGS;
+		sleepable = kfunc_meta->flags & KF_SLEEPABLE;
+	}
+
+	/* check that BTF function arguments match actual types that the
+	 * verifier sees.
+	 */
+	for (i = 0; i < nargs; i++) {
+		enum bpf_arg_type arg_type = ARG_DONTCARE;
+		u32 regno = i + 1;
+		struct bpf_reg_state *reg = &regs[regno];
+		bool obj_ptr = false;
+
+		t = btf_type_skip_modifiers(btf, args[i].type, NULL);
+		if (btf_type_is_scalar(t)) {
+			if (is_kfunc && kfunc_meta) {
+				bool is_buf_size = false;
+
+				/* check for any const scalar parameter of name "rdonly_buf_size"
+				 * or "rdwr_buf_size"
+				 */
+				if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg,
+							      "rdonly_buf_size")) {
+					kfunc_meta->r0_rdonly = true;
+					is_buf_size = true;
+				} else if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg,
+								     "rdwr_buf_size"))
+					is_buf_size = true;
+
+				if (is_buf_size) {
+					if (kfunc_meta->r0_size) {
+						bpf_log(log, "2 or more rdonly/rdwr_buf_size parameters for kfunc");
+						return -EINVAL;
+					}
+
+					if (!tnum_is_const(reg->var_off)) {
+						bpf_log(log, "R%d is not a const\n", regno);
+						return -EINVAL;
+					}
+
+					kfunc_meta->r0_size = reg->var_off.value;
+					ret = mark_chain_precision(env, regno);
+					if (ret)
+						return ret;
+				}
+			}
+
+			if (reg->type == SCALAR_VALUE)
+				continue;
+			bpf_log(log, "R%d is not a scalar\n", regno);
+			return -EINVAL;
+		}
+
+		if (!btf_type_is_ptr(t)) {
+			bpf_log(log, "Unrecognized arg#%d type %s\n",
+				i, btf_type_str(t));
+			return -EINVAL;
+		}
+
+		/* These register types have special constraints wrt ref_obj_id
+		 * and offset checks. The rest of trusted args don't.
+		 */
+		obj_ptr = reg->type == PTR_TO_CTX || reg->type == PTR_TO_BTF_ID ||
+			  reg2btf_ids[base_type(reg->type)];
+
+		/* Check if argument must be a referenced pointer, args + i has
+		 * been verified to be a pointer (after skipping modifiers).
+		 * PTR_TO_CTX is ok without having non-zero ref_obj_id.
+		 */
+		if (is_kfunc && trusted_args && (obj_ptr && reg->type != PTR_TO_CTX) && !reg->ref_obj_id) {
+			bpf_log(log, "R%d must be referenced\n", regno);
+			return -EINVAL;
+		}
+
+		ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
+		ref_tname = btf_name_by_offset(btf, ref_t->name_off);
+
+		/* Trusted args have the same offset checks as release arguments */
+		if ((trusted_args && obj_ptr) || (rel && reg->ref_obj_id))
+			arg_type |= OBJ_RELEASE;
+		ret = check_func_arg_reg_off(env, reg, regno, arg_type);
+		if (ret < 0)
+			return ret;
+
+		if (is_kfunc && reg->ref_obj_id) {
+			/* Ensure only one argument is referenced PTR_TO_BTF_ID */
+			if (ref_obj_id) {
+				bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
+					regno, reg->ref_obj_id, ref_obj_id);
+				return -EFAULT;
+			}
+			ref_regno = regno;
+			ref_obj_id = reg->ref_obj_id;
+		}
+
+		/* kptr_get is only true for kfunc */
+		if (i == 0 && kptr_get) {
+			struct bpf_map_value_off_desc *off_desc;
+
+			if (reg->type != PTR_TO_MAP_VALUE) {
+				bpf_log(log, "arg#0 expected pointer to map value\n");
+				return -EINVAL;
+			}
+
+			/* check_func_arg_reg_off allows var_off for
+			 * PTR_TO_MAP_VALUE, but we need fixed offset to find
+			 * off_desc.
+			 */
+			if (!tnum_is_const(reg->var_off)) {
+				bpf_log(log, "arg#0 must have constant offset\n");
+				return -EINVAL;
+			}
+
+			off_desc = bpf_map_kptr_off_contains(reg->map_ptr, reg->off + reg->var_off.value);
+			if (!off_desc || off_desc->type != BPF_KPTR_REF) {
+				bpf_log(log, "arg#0 no referenced kptr at map value offset=%llu\n",
+					reg->off + reg->var_off.value);
+				return -EINVAL;
+			}
+
+			if (!btf_type_is_ptr(ref_t)) {
+				bpf_log(log, "arg#0 BTF type must be a double pointer\n");
+				return -EINVAL;
+			}
+
+			ref_t = btf_type_skip_modifiers(btf, ref_t->type, &ref_id);
+			ref_tname = btf_name_by_offset(btf, ref_t->name_off);
+
+			if (!btf_type_is_struct(ref_t)) {
+				bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
+					func_name, i, btf_type_str(ref_t), ref_tname);
+				return -EINVAL;
+			}
+			if (!btf_struct_ids_match(log, btf, ref_id, 0, off_desc->kptr.btf,
+						  off_desc->kptr.btf_id, true)) {
+				bpf_log(log, "kernel function %s args#%d expected pointer to %s %s\n",
+					func_name, i, btf_type_str(ref_t), ref_tname);
+				return -EINVAL;
+			}
+			/* rest of the arguments can be anything, like normal kfunc */
+		} else if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
+			/* If function expects ctx type in BTF check that caller
+			 * is passing PTR_TO_CTX.
+			 */
+			if (reg->type != PTR_TO_CTX) {
+				bpf_log(log,
+					"arg#%d expected pointer to ctx, but got %s\n",
+					i, btf_type_str(t));
+				return -EINVAL;
+			}
+		} else if (is_kfunc && (reg->type == PTR_TO_BTF_ID ||
+			   (reg2btf_ids[base_type(reg->type)] && !type_flag(reg->type)))) {
+			const struct btf_type *reg_ref_t;
+			const struct btf *reg_btf;
+			const char *reg_ref_tname;
+			u32 reg_ref_id;
+
+			if (!btf_type_is_struct(ref_t)) {
+				bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
+					func_name, i, btf_type_str(ref_t),
+					ref_tname);
+				return -EINVAL;
+			}
+
+			if (reg->type == PTR_TO_BTF_ID) {
+				reg_btf = reg->btf;
+				reg_ref_id = reg->btf_id;
+			} else {
+				reg_btf = btf_vmlinux;
+				reg_ref_id = *reg2btf_ids[base_type(reg->type)];
+			}
+
+			reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id,
+							    &reg_ref_id);
+			reg_ref_tname = btf_name_by_offset(reg_btf,
+							   reg_ref_t->name_off);
+			if (!btf_struct_ids_match(log, reg_btf, reg_ref_id,
+						  reg->off, btf, ref_id,
+						  trusted_args || (rel && reg->ref_obj_id))) {
+				bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
+					func_name, i,
+					btf_type_str(ref_t), ref_tname,
+					regno, btf_type_str(reg_ref_t),
+					reg_ref_tname);
+				return -EINVAL;
+			}
+		} else if (ptr_to_mem_ok && processing_call) {
+			const struct btf_type *resolve_ret;
+			u32 type_size;
+
+			if (is_kfunc) {
+				bool arg_mem_size = i + 1 < nargs && is_kfunc_arg_mem_size(btf, &args[i + 1], &regs[regno + 1]);
+				bool arg_dynptr = btf_type_is_struct(ref_t) &&
+						  !strcmp(ref_tname,
+							  stringify_struct(bpf_dynptr_kern));
+
+				/* Permit pointer to mem, but only when argument
+				 * type is pointer to scalar, or struct composed
+				 * (recursively) of scalars.
+				 * When arg_mem_size is true, the pointer can be
+				 * void *.
+				 * Also permit initialized local dynamic pointers.
+				 */
+				if (!btf_type_is_scalar(ref_t) &&
+				    !__btf_type_is_scalar_struct(log, btf, ref_t, 0) &&
+				    !arg_dynptr &&
+				    (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
+					bpf_log(log,
+						"arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
+						i, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
+					return -EINVAL;
+				}
+
+				if (arg_dynptr) {
+					if (reg->type != PTR_TO_STACK) {
+						bpf_log(log, "arg#%d pointer type %s %s not to stack\n",
+							i, btf_type_str(ref_t),
+							ref_tname);
+						return -EINVAL;
+					}
+
+					if (!is_dynptr_reg_valid_init(env, reg)) {
+						bpf_log(log,
+							"arg#%d pointer type %s %s must be valid and initialized\n",
+							i, btf_type_str(ref_t),
+							ref_tname);
+						return -EINVAL;
+					}
+
+					if (!is_dynptr_type_expected(env, reg,
+							ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL)) {
+						bpf_log(log,
+							"arg#%d pointer type %s %s points to unsupported dynamic pointer type\n",
+							i, btf_type_str(ref_t),
+							ref_tname);
+						return -EINVAL;
+					}
+
+					continue;
+				}
+
+				/* Check for mem, len pair */
+				if (arg_mem_size) {
+					if (check_kfunc_mem_size_reg(env, &regs[regno + 1], regno + 1)) {
+						bpf_log(log, "arg#%d arg#%d memory, len pair leads to invalid memory access\n",
+							i, i + 1);
+						return -EINVAL;
+					}
+					i++;
+					continue;
+				}
+			}
+
+			resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
+			if (IS_ERR(resolve_ret)) {
+				bpf_log(log,
+					"arg#%d reference type('%s %s') size cannot be determined: %ld\n",
+					i, btf_type_str(ref_t), ref_tname,
+					PTR_ERR(resolve_ret));
+				return -EINVAL;
+			}
+
+			if (check_mem_reg(env, reg, regno, type_size))
+				return -EINVAL;
+		} else {
+			bpf_log(log, "reg type unsupported for arg#%d %sfunction %s#%d\n", i,
+				is_kfunc ? "kernel " : "", func_name, func_id);
+			return -EINVAL;
+		}
+	}
+
+	/* Either both are set, or neither */
+	WARN_ON_ONCE((ref_obj_id && !ref_regno) || (!ref_obj_id && ref_regno));
+	/* We already made sure ref_obj_id is set only for one argument. We do
+	 * allow (!rel && ref_obj_id), so that passing such referenced
+	 * PTR_TO_BTF_ID to other kfuncs works. Note that rel is only true when
+	 * is_kfunc is true.
+	 */
+	if (rel && !ref_obj_id) {
+		bpf_log(log, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
+			func_name);
+		return -EINVAL;
+	}
+
+	if (sleepable && !env->prog->aux->sleepable) {
+		bpf_log(log, "kernel function %s is sleepable but the program is not\n",
+			func_name);
+		return -EINVAL;
+	}
+
+	if (kfunc_meta && ref_obj_id)
+		kfunc_meta->ref_obj_id = ref_obj_id;
+
+	/* returns argument register number > 0 in case of reference release kfunc */
+	return rel ? ref_regno : 0;
+}
+
+/* Compare BTF of a function declaration with given bpf_reg_state.
+ * Returns:
+ * EFAULT - there is a verifier bug. Abort verification.
+ * EINVAL - there is a type mismatch or BTF is not available.
+ * 0 - BTF matches with what bpf_reg_state expects.
+ * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
+ */
+int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
+				struct bpf_reg_state *regs)
+{
+	struct bpf_prog *prog = env->prog;
+	struct btf *btf = prog->aux->btf;
+	bool is_global;
+	u32 btf_id;
+	int err;
+
+	if (!prog->aux->func_info)
+		return -EINVAL;
+
+	btf_id = prog->aux->func_info[subprog].type_id;
+	if (!btf_id)
+		return -EFAULT;
+
+	if (prog->aux->func_info_aux[subprog].unreliable)
+		return -EINVAL;
+
+	is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
+	err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, false);
+
+	/* Compiler optimizations can remove arguments from static functions
+	 * or mismatched type can be passed into a global function.
+	 * In such cases mark the function as unreliable from BTF point of view.
+	 */
+	if (err)
+		prog->aux->func_info_aux[subprog].unreliable = true;
+	return err;
+}
+
+/* Compare BTF of a function call with given bpf_reg_state.
+ * Returns:
+ * EFAULT - there is a verifier bug. Abort verification.
+ * EINVAL - there is a type mismatch or BTF is not available.
+ * 0 - BTF matches with what bpf_reg_state expects.
+ * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
+ *
+ * NOTE: the code is duplicated from btf_check_subprog_arg_match()
+ * because btf_check_func_arg_match() is still doing both. Once that
+ * function is split in 2, we can call from here btf_check_subprog_arg_match()
+ * first, and then treat the calling part in a new code path.
+ */
+int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog,
+			   struct bpf_reg_state *regs)
+{
+	struct bpf_prog *prog = env->prog;
+	struct btf *btf = prog->aux->btf;
+	bool is_global;
+	u32 btf_id;
+	int err;
+
+	if (!prog->aux->func_info)
+		return -EINVAL;
+
+	btf_id = prog->aux->func_info[subprog].type_id;
+	if (!btf_id)
+		return -EFAULT;
+
+	if (prog->aux->func_info_aux[subprog].unreliable)
+		return -EINVAL;
+
+	is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
+	err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, true);
+
+	/* Compiler optimizations can remove arguments from static functions
+	 * or mismatched type can be passed into a global function.
+	 * In such cases mark the function as unreliable from BTF point of view.
+	 */
+	if (err)
+		prog->aux->func_info_aux[subprog].unreliable = true;
+	return err;
+}
+
+int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
+			      const struct btf *btf, u32 func_id,
+			      struct bpf_reg_state *regs,
+			      struct bpf_kfunc_arg_meta *meta)
+{
+	return btf_check_func_arg_match(env, btf, func_id, regs, true, meta, true);
+}
+
+/* Convert BTF of a function into bpf_reg_state if possible
+ * Returns:
+ * EFAULT - there is a verifier bug. Abort verification.
+ * EINVAL - cannot convert BTF.
+ * 0 - Successfully converted BTF into bpf_reg_state
+ * (either PTR_TO_CTX or SCALAR_VALUE).
+ */
+int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
+			  struct bpf_reg_state *regs)
+{
+	struct bpf_verifier_log *log = &env->log;
+	struct bpf_prog *prog = env->prog;
+	enum bpf_prog_type prog_type = prog->type;
+	struct btf *btf = prog->aux->btf;
+	const struct btf_param *args;
+	const struct btf_type *t, *ref_t;
+	u32 i, nargs, btf_id;
+	const char *tname;
+
+	if (!prog->aux->func_info ||
+	    prog->aux->func_info_aux[subprog].linkage != BTF_FUNC_GLOBAL) {
+		bpf_log(log, "Verifier bug\n");
+		return -EFAULT;
+	}
+
+	btf_id = prog->aux->func_info[subprog].type_id;
+	if (!btf_id) {
+		bpf_log(log, "Global functions need valid BTF\n");
+		return -EFAULT;
+	}
+
+	t = btf_type_by_id(btf, btf_id);
+	if (!t || !btf_type_is_func(t)) {
+		/* These checks were already done by the verifier while loading
+		 * struct bpf_func_info
+		 */
+		bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
+			subprog);
+		return -EFAULT;
+	}
+	tname = btf_name_by_offset(btf, t->name_off);
+
+	if (log->level & BPF_LOG_LEVEL)
+		bpf_log(log, "Validating %s() func#%d...\n",
+			tname, subprog);
+
+	if (prog->aux->func_info_aux[subprog].unreliable) {
+		bpf_log(log, "Verifier bug in function %s()\n", tname);
+		return -EFAULT;
+	}
+	if (prog_type == BPF_PROG_TYPE_EXT)
+		prog_type = prog->aux->dst_prog->type;
+
+	t = btf_type_by_id(btf, t->type);
+	if (!t || !btf_type_is_func_proto(t)) {
+		bpf_log(log, "Invalid type of function %s()\n", tname);
+		return -EFAULT;
+	}
+	args = (const struct btf_param *)(t + 1);
+	nargs = btf_type_vlen(t);
+	if (nargs > MAX_BPF_FUNC_REG_ARGS) {
+		bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
+			tname, nargs, MAX_BPF_FUNC_REG_ARGS);
+		return -EINVAL;
+	}
+	/* check that function returns int */
+	t = btf_type_by_id(btf, t->type);
+	while (btf_type_is_modifier(t))
+		t = btf_type_by_id(btf, t->type);
+	if (!btf_type_is_int(t) && !btf_is_any_enum(t)) {
+		bpf_log(log,
+			"Global function %s() doesn't return scalar. Only those are supported.\n",
+			tname);
+		return -EINVAL;
+	}
+	/* Convert BTF function arguments into verifier types.
+	 * Only PTR_TO_CTX and SCALAR are supported atm.
+	 */
+	for (i = 0; i < nargs; i++) {
+		struct bpf_reg_state *reg = &regs[i + 1];
+
+		t = btf_type_by_id(btf, args[i].type);
+		while (btf_type_is_modifier(t))
+			t = btf_type_by_id(btf, t->type);
+		if (btf_type_is_int(t) || btf_is_any_enum(t)) {
+			reg->type = SCALAR_VALUE;
+			continue;
+		}
+		if (btf_type_is_ptr(t)) {
+			if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
+				reg->type = PTR_TO_CTX;
+				continue;
+			}
+
+			t = btf_type_skip_modifiers(btf, t->type, NULL);
+
+			ref_t = btf_resolve_size(btf, t, &reg->mem_size);
+			if (IS_ERR(ref_t)) {
+				bpf_log(log,
+				    "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
+				    i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
+					PTR_ERR(ref_t));
+				return -EINVAL;
+			}
+
+			reg->type = PTR_TO_MEM | PTR_MAYBE_NULL;
+			reg->id = ++env->id_gen;
+
+			continue;
+		}
+		bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
+			i, btf_type_str(t), tname);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
+			  struct btf_show *show)
+{
+	const struct btf_type *t = btf_type_by_id(btf, type_id);
+
+	show->btf = btf;
+	memset(&show->state, 0, sizeof(show->state));
+	memset(&show->obj, 0, sizeof(show->obj));
+
+	btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
+}
+
+static void btf_seq_show(struct btf_show *show, const char *fmt,
+			 va_list args)
+{
+	seq_vprintf((struct seq_file *)show->target, fmt, args);
+}
+
+int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
+			    void *obj, struct seq_file *m, u64 flags)
+{
+	struct btf_show sseq;
+
+	sseq.target = m;
+	sseq.showfn = btf_seq_show;
+	sseq.flags = flags;
+
+	btf_type_show(btf, type_id, obj, &sseq);
+
+	return sseq.state.status;
+}
+
+void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
+		       struct seq_file *m)
+{
+	(void) btf_type_seq_show_flags(btf, type_id, obj, m,
+				       BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
+				       BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
+}
+
+struct btf_show_snprintf {
+	struct btf_show show;
+	int len_left;		/* space left in string */
+	int len;		/* length we would have written */
+};
+
+static void btf_snprintf_show(struct btf_show *show, const char *fmt,
+			      va_list args)
+{
+	struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
+	int len;
+
+	len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
+
+	if (len < 0) {
+		ssnprintf->len_left = 0;
+		ssnprintf->len = len;
+	} else if (len >= ssnprintf->len_left) {
+		/* no space, drive on to get length we would have written */
+		ssnprintf->len_left = 0;
+		ssnprintf->len += len;
+	} else {
+		ssnprintf->len_left -= len;
+		ssnprintf->len += len;
+		show->target += len;
+	}
+}
+
+int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
+			   char *buf, int len, u64 flags)
+{
+	struct btf_show_snprintf ssnprintf;
+
+	ssnprintf.show.target = buf;
+	ssnprintf.show.flags = flags;
+	ssnprintf.show.showfn = btf_snprintf_show;
+	ssnprintf.len_left = len;
+	ssnprintf.len = 0;
+
+	btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
+
+	/* If we encountered an error, return it. */
+	if (ssnprintf.show.state.status)
+		return ssnprintf.show.state.status;
+
+	/* Otherwise return length we would have written */
+	return ssnprintf.len;
+}
+
+#ifdef CONFIG_PROC_FS
+static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
+{
+	const struct btf *btf = filp->private_data;
+
+	seq_printf(m, "btf_id:\t%u\n", btf->id);
+}
+#endif
+
+static int btf_release(struct inode *inode, struct file *filp)
+{
+	btf_put(filp->private_data);
+	return 0;
+}
+
+const struct file_operations btf_fops = {
+#ifdef CONFIG_PROC_FS
+	.show_fdinfo	= bpf_btf_show_fdinfo,
+#endif
+	.release	= btf_release,
+};
+
+static int __btf_new_fd(struct btf *btf)
+{
+	return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
+}
+
+int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr)
+{
+	struct btf *btf;
+	int ret;
+
+	btf = btf_parse(make_bpfptr(attr->btf, uattr.is_kernel),
+			attr->btf_size, attr->btf_log_level,
+			u64_to_user_ptr(attr->btf_log_buf),
+			attr->btf_log_size);
+	if (IS_ERR(btf))
+		return PTR_ERR(btf);
+
+	ret = btf_alloc_id(btf);
+	if (ret) {
+		btf_free(btf);
+		return ret;
+	}
+
+	/*
+	 * The BTF ID is published to the userspace.
+	 * All BTF free must go through call_rcu() from
+	 * now on (i.e. free by calling btf_put()).
+	 */
+
+	ret = __btf_new_fd(btf);
+	if (ret < 0)
+		btf_put(btf);
+
+	return ret;
+}
+
+struct btf *btf_get_by_fd(int fd)
+{
+	struct btf *btf;
+	struct fd f;
+
+	f = fdget(fd);
+
+	if (!f.file)
+		return ERR_PTR(-EBADF);
+
+	if (f.file->f_op != &btf_fops) {
+		fdput(f);
+		return ERR_PTR(-EINVAL);
+	}
+
+	btf = f.file->private_data;
+	refcount_inc(&btf->refcnt);
+	fdput(f);
+
+	return btf;
+}
+
+int btf_get_info_by_fd(const struct btf *btf,
+		       const union bpf_attr *attr,
+		       union bpf_attr __user *uattr)
+{
+	struct bpf_btf_info __user *uinfo;
+	struct bpf_btf_info info;
+	u32 info_copy, btf_copy;
+	void __user *ubtf;
+	char __user *uname;
+	u32 uinfo_len, uname_len, name_len;
+	int ret = 0;
+
+	uinfo = u64_to_user_ptr(attr->info.info);
+	uinfo_len = attr->info.info_len;
+
+	info_copy = min_t(u32, uinfo_len, sizeof(info));
+	memset(&info, 0, sizeof(info));
+	if (copy_from_user(&info, uinfo, info_copy))
+		return -EFAULT;
+
+	info.id = btf->id;
+	ubtf = u64_to_user_ptr(info.btf);
+	btf_copy = min_t(u32, btf->data_size, info.btf_size);
+	if (copy_to_user(ubtf, btf->data, btf_copy))
+		return -EFAULT;
+	info.btf_size = btf->data_size;
+
+	info.kernel_btf = btf->kernel_btf;
+
+	uname = u64_to_user_ptr(info.name);
+	uname_len = info.name_len;
+	if (!uname ^ !uname_len)
+		return -EINVAL;
+
+	name_len = strlen(btf->name);
+	info.name_len = name_len;
+
+	if (uname) {
+		if (uname_len >= name_len + 1) {
+			if (copy_to_user(uname, btf->name, name_len + 1))
+				return -EFAULT;
+		} else {
+			char zero = '\0';
+
+			if (copy_to_user(uname, btf->name, uname_len - 1))
+				return -EFAULT;
+			if (put_user(zero, uname + uname_len - 1))
+				return -EFAULT;
+			/* let user-space know about too short buffer */
+			ret = -ENOSPC;
+		}
+	}
+
+	if (copy_to_user(uinfo, &info, info_copy) ||
+	    put_user(info_copy, &uattr->info.info_len))
+		return -EFAULT;
+
+	return ret;
+}
+
+int btf_get_fd_by_id(u32 id)
+{
+	struct btf *btf;
+	int fd;
+
+	rcu_read_lock();
+	btf = idr_find(&btf_idr, id);
+	if (!btf || !refcount_inc_not_zero(&btf->refcnt))
+		btf = ERR_PTR(-ENOENT);
+	rcu_read_unlock();
+
+	if (IS_ERR(btf))
+		return PTR_ERR(btf);
+
+	fd = __btf_new_fd(btf);
+	if (fd < 0)
+		btf_put(btf);
+
+	return fd;
+}
+
+u32 btf_obj_id(const struct btf *btf)
+{
+	return btf->id;
+}
+
+bool btf_is_kernel(const struct btf *btf)
+{
+	return btf->kernel_btf;
+}
+
+bool btf_is_module(const struct btf *btf)
+{
+	return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
+}
+
+static int btf_id_cmp_func(const void *a, const void *b)
+{
+	const int *pa = a, *pb = b;
+
+	return *pa - *pb;
+}
+
+bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
+{
+	return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
+}
+
+static void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id)
+{
+	return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func);
+}
+
+enum {
+	BTF_MODULE_F_LIVE = (1 << 0),
+};
+
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+struct btf_module {
+	struct list_head list;
+	struct module *module;
+	struct btf *btf;
+	struct bin_attribute *sysfs_attr;
+	int flags;
+};
+
+static LIST_HEAD(btf_modules);
+static DEFINE_MUTEX(btf_module_mutex);
+
+static ssize_t
+btf_module_read(struct file *file, struct kobject *kobj,
+		struct bin_attribute *bin_attr,
+		char *buf, loff_t off, size_t len)
+{
+	const struct btf *btf = bin_attr->private;
+
+	memcpy(buf, btf->data + off, len);
+	return len;
+}
+
+static void purge_cand_cache(struct btf *btf);
+
+static int btf_module_notify(struct notifier_block *nb, unsigned long op,
+			     void *module)
+{
+	struct btf_module *btf_mod, *tmp;
+	struct module *mod = module;
+	struct btf *btf;
+	int err = 0;
+
+	if (mod->btf_data_size == 0 ||
+	    (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
+	     op != MODULE_STATE_GOING))
+		goto out;
+
+	switch (op) {
+	case MODULE_STATE_COMING:
+		btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
+		if (!btf_mod) {
+			err = -ENOMEM;
+			goto out;
+		}
+		btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
+		if (IS_ERR(btf)) {
+			pr_warn("failed to validate module [%s] BTF: %ld\n",
+				mod->name, PTR_ERR(btf));
+			kfree(btf_mod);
+			if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
+				err = PTR_ERR(btf);
+			goto out;
+		}
+		err = btf_alloc_id(btf);
+		if (err) {
+			btf_free(btf);
+			kfree(btf_mod);
+			goto out;
+		}
+
+		purge_cand_cache(NULL);
+		mutex_lock(&btf_module_mutex);
+		btf_mod->module = module;
+		btf_mod->btf = btf;
+		list_add(&btf_mod->list, &btf_modules);
+		mutex_unlock(&btf_module_mutex);
+
+		if (IS_ENABLED(CONFIG_SYSFS)) {
+			struct bin_attribute *attr;
+
+			attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+			if (!attr)
+				goto out;
+
+			sysfs_bin_attr_init(attr);
+			attr->attr.name = btf->name;
+			attr->attr.mode = 0444;
+			attr->size = btf->data_size;
+			attr->private = btf;
+			attr->read = btf_module_read;
+
+			err = sysfs_create_bin_file(btf_kobj, attr);
+			if (err) {
+				pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
+					mod->name, err);
+				kfree(attr);
+				err = 0;
+				goto out;
+			}
+
+			btf_mod->sysfs_attr = attr;
+		}
+
+		break;
+	case MODULE_STATE_LIVE:
+		mutex_lock(&btf_module_mutex);
+		list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
+			if (btf_mod->module != module)
+				continue;
+
+			btf_mod->flags |= BTF_MODULE_F_LIVE;
+			break;
+		}
+		mutex_unlock(&btf_module_mutex);
+		break;
+	case MODULE_STATE_GOING:
+		mutex_lock(&btf_module_mutex);
+		list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
+			if (btf_mod->module != module)
+				continue;
+
+			list_del(&btf_mod->list);
+			if (btf_mod->sysfs_attr)
+				sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
+			purge_cand_cache(btf_mod->btf);
+			btf_put(btf_mod->btf);
+			kfree(btf_mod->sysfs_attr);
+			kfree(btf_mod);
+			break;
+		}
+		mutex_unlock(&btf_module_mutex);
+		break;
+	}
+out:
+	return notifier_from_errno(err);
+}
+
+static struct notifier_block btf_module_nb = {
+	.notifier_call = btf_module_notify,
+};
+
+static int __init btf_module_init(void)
+{
+	register_module_notifier(&btf_module_nb);
+	return 0;
+}
+
+fs_initcall(btf_module_init);
+#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
+
+struct module *btf_try_get_module(const struct btf *btf)
+{
+	struct module *res = NULL;
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+	struct btf_module *btf_mod, *tmp;
+
+	mutex_lock(&btf_module_mutex);
+	list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
+		if (btf_mod->btf != btf)
+			continue;
+
+		/* We must only consider module whose __init routine has
+		 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
+		 * which is set from the notifier callback for
+		 * MODULE_STATE_LIVE.
+		 */
+		if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
+			res = btf_mod->module;
+
+		break;
+	}
+	mutex_unlock(&btf_module_mutex);
+#endif
+
+	return res;
+}
+
+/* Returns struct btf corresponding to the struct module.
+ * This function can return NULL or ERR_PTR.
+ */
+static struct btf *btf_get_module_btf(const struct module *module)
+{
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+	struct btf_module *btf_mod, *tmp;
+#endif
+	struct btf *btf = NULL;
+
+	if (!module) {
+		btf = bpf_get_btf_vmlinux();
+		if (!IS_ERR_OR_NULL(btf))
+			btf_get(btf);
+		return btf;
+	}
+
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+	mutex_lock(&btf_module_mutex);
+	list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
+		if (btf_mod->module != module)
+			continue;
+
+		btf_get(btf_mod->btf);
+		btf = btf_mod->btf;
+		break;
+	}
+	mutex_unlock(&btf_module_mutex);
+#endif
+
+	return btf;
+}
+
+BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
+{
+	struct btf *btf = NULL;
+	int btf_obj_fd = 0;
+	long ret;
+
+	if (flags)
+		return -EINVAL;
+
+	if (name_sz <= 1 || name[name_sz - 1])
+		return -EINVAL;
+
+	ret = bpf_find_btf_id(name, kind, &btf);
+	if (ret > 0 && btf_is_module(btf)) {
+		btf_obj_fd = __btf_new_fd(btf);
+		if (btf_obj_fd < 0) {
+			btf_put(btf);
+			return btf_obj_fd;
+		}
+		return ret | (((u64)btf_obj_fd) << 32);
+	}
+	if (ret > 0)
+		btf_put(btf);
+	return ret;
+}
+
+const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
+	.func		= bpf_btf_find_by_name_kind,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg2_type	= ARG_CONST_SIZE,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
+#define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
+BTF_TRACING_TYPE_xxx
+#undef BTF_TRACING_TYPE
+
+/* Kernel Function (kfunc) BTF ID set registration API */
+
+static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
+				  struct btf_id_set8 *add_set)
+{
+	bool vmlinux_set = !btf_is_module(btf);
+	struct btf_kfunc_set_tab *tab;
+	struct btf_id_set8 *set;
+	u32 set_cnt;
+	int ret;
+
+	if (hook >= BTF_KFUNC_HOOK_MAX) {
+		ret = -EINVAL;
+		goto end;
+	}
+
+	if (!add_set->cnt)
+		return 0;
+
+	tab = btf->kfunc_set_tab;
+	if (!tab) {
+		tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
+		if (!tab)
+			return -ENOMEM;
+		btf->kfunc_set_tab = tab;
+	}
+
+	set = tab->sets[hook];
+	/* Warn when register_btf_kfunc_id_set is called twice for the same hook
+	 * for module sets.
+	 */
+	if (WARN_ON_ONCE(set && !vmlinux_set)) {
+		ret = -EINVAL;
+		goto end;
+	}
+
+	/* We don't need to allocate, concatenate, and sort module sets, because
+	 * only one is allowed per hook. Hence, we can directly assign the
+	 * pointer and return.
+	 */
+	if (!vmlinux_set) {
+		tab->sets[hook] = add_set;
+		return 0;
+	}
+
+	/* In case of vmlinux sets, there may be more than one set being
+	 * registered per hook. To create a unified set, we allocate a new set
+	 * and concatenate all individual sets being registered. While each set
+	 * is individually sorted, they may become unsorted when concatenated,
+	 * hence re-sorting the final set again is required to make binary
+	 * searching the set using btf_id_set8_contains function work.
+	 */
+	set_cnt = set ? set->cnt : 0;
+
+	if (set_cnt > U32_MAX - add_set->cnt) {
+		ret = -EOVERFLOW;
+		goto end;
+	}
+
+	if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
+		ret = -E2BIG;
+		goto end;
+	}
+
+	/* Grow set */
+	set = krealloc(tab->sets[hook],
+		       offsetof(struct btf_id_set8, pairs[set_cnt + add_set->cnt]),
+		       GFP_KERNEL | __GFP_NOWARN);
+	if (!set) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+	/* For newly allocated set, initialize set->cnt to 0 */
+	if (!tab->sets[hook])
+		set->cnt = 0;
+	tab->sets[hook] = set;
+
+	/* Concatenate the two sets */
+	memcpy(set->pairs + set->cnt, add_set->pairs, add_set->cnt * sizeof(set->pairs[0]));
+	set->cnt += add_set->cnt;
+
+	sort(set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func, NULL);
+
+	return 0;
+end:
+	btf_free_kfunc_set_tab(btf);
+	return ret;
+}
+
+static u32 *__btf_kfunc_id_set_contains(const struct btf *btf,
+					enum btf_kfunc_hook hook,
+					u32 kfunc_btf_id)
+{
+	struct btf_id_set8 *set;
+	u32 *id;
+
+	if (hook >= BTF_KFUNC_HOOK_MAX)
+		return NULL;
+	if (!btf->kfunc_set_tab)
+		return NULL;
+	set = btf->kfunc_set_tab->sets[hook];
+	if (!set)
+		return NULL;
+	id = btf_id_set8_contains(set, kfunc_btf_id);
+	if (!id)
+		return NULL;
+	/* The flags for BTF ID are located next to it */
+	return id + 1;
+}
+
+static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
+{
+	switch (prog_type) {
+	case BPF_PROG_TYPE_XDP:
+		return BTF_KFUNC_HOOK_XDP;
+	case BPF_PROG_TYPE_SCHED_CLS:
+		return BTF_KFUNC_HOOK_TC;
+	case BPF_PROG_TYPE_STRUCT_OPS:
+		return BTF_KFUNC_HOOK_STRUCT_OPS;
+	case BPF_PROG_TYPE_TRACING:
+	case BPF_PROG_TYPE_LSM:
+		return BTF_KFUNC_HOOK_TRACING;
+	case BPF_PROG_TYPE_SYSCALL:
+		return BTF_KFUNC_HOOK_SYSCALL;
+	default:
+		return BTF_KFUNC_HOOK_MAX;
+	}
+}
+
+/* Caution:
+ * Reference to the module (obtained using btf_try_get_module) corresponding to
+ * the struct btf *MUST* be held when calling this function from verifier
+ * context. This is usually true as we stash references in prog's kfunc_btf_tab;
+ * keeping the reference for the duration of the call provides the necessary
+ * protection for looking up a well-formed btf->kfunc_set_tab.
+ */
+u32 *btf_kfunc_id_set_contains(const struct btf *btf,
+			       enum bpf_prog_type prog_type,
+			       u32 kfunc_btf_id)
+{
+	enum btf_kfunc_hook hook;
+
+	hook = bpf_prog_type_to_kfunc_hook(prog_type);
+	return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id);
+}
+
+/* This function must be invoked only from initcalls/module init functions */
+int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
+			      const struct btf_kfunc_id_set *kset)
+{
+	enum btf_kfunc_hook hook;
+	struct btf *btf;
+	int ret;
+
+	btf = btf_get_module_btf(kset->owner);
+	if (!btf) {
+		if (!kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
+			pr_err("missing vmlinux BTF, cannot register kfuncs\n");
+			return -ENOENT;
+		}
+		if (kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES))
+			pr_warn("missing module BTF, cannot register kfuncs\n");
+		return 0;
+	}
+	if (IS_ERR(btf))
+		return PTR_ERR(btf);
+
+	hook = bpf_prog_type_to_kfunc_hook(prog_type);
+	ret = btf_populate_kfunc_set(btf, hook, kset->set);
+	btf_put(btf);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
+
+s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
+{
+	struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
+	struct btf_id_dtor_kfunc *dtor;
+
+	if (!tab)
+		return -ENOENT;
+	/* Even though the size of tab->dtors[0] is > sizeof(u32), we only need
+	 * to compare the first u32 with btf_id, so we can reuse btf_id_cmp_func.
+	 */
+	BUILD_BUG_ON(offsetof(struct btf_id_dtor_kfunc, btf_id) != 0);
+	dtor = bsearch(&btf_id, tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func);
+	if (!dtor)
+		return -ENOENT;
+	return dtor->kfunc_btf_id;
+}
+
+static int btf_check_dtor_kfuncs(struct btf *btf, const struct btf_id_dtor_kfunc *dtors, u32 cnt)
+{
+	const struct btf_type *dtor_func, *dtor_func_proto, *t;
+	const struct btf_param *args;
+	s32 dtor_btf_id;
+	u32 nr_args, i;
+
+	for (i = 0; i < cnt; i++) {
+		dtor_btf_id = dtors[i].kfunc_btf_id;
+
+		dtor_func = btf_type_by_id(btf, dtor_btf_id);
+		if (!dtor_func || !btf_type_is_func(dtor_func))
+			return -EINVAL;
+
+		dtor_func_proto = btf_type_by_id(btf, dtor_func->type);
+		if (!dtor_func_proto || !btf_type_is_func_proto(dtor_func_proto))
+			return -EINVAL;
+
+		/* Make sure the prototype of the destructor kfunc is 'void func(type *)' */
+		t = btf_type_by_id(btf, dtor_func_proto->type);
+		if (!t || !btf_type_is_void(t))
+			return -EINVAL;
+
+		nr_args = btf_type_vlen(dtor_func_proto);
+		if (nr_args != 1)
+			return -EINVAL;
+		args = btf_params(dtor_func_proto);
+		t = btf_type_by_id(btf, args[0].type);
+		/* Allow any pointer type, as width on targets Linux supports
+		 * will be same for all pointer types (i.e. sizeof(void *))
+		 */
+		if (!t || !btf_type_is_ptr(t))
+			return -EINVAL;
+	}
+	return 0;
+}
+
+/* This function must be invoked only from initcalls/module init functions */
+int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
+				struct module *owner)
+{
+	struct btf_id_dtor_kfunc_tab *tab;
+	struct btf *btf;
+	u32 tab_cnt;
+	int ret;
+
+	btf = btf_get_module_btf(owner);
+	if (!btf) {
+		if (!owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
+			pr_err("missing vmlinux BTF, cannot register dtor kfuncs\n");
+			return -ENOENT;
+		}
+		if (owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) {
+			pr_err("missing module BTF, cannot register dtor kfuncs\n");
+			return -ENOENT;
+		}
+		return 0;
+	}
+	if (IS_ERR(btf))
+		return PTR_ERR(btf);
+
+	if (add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
+		pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
+		ret = -E2BIG;
+		goto end;
+	}
+
+	/* Ensure that the prototype of dtor kfuncs being registered is sane */
+	ret = btf_check_dtor_kfuncs(btf, dtors, add_cnt);
+	if (ret < 0)
+		goto end;
+
+	tab = btf->dtor_kfunc_tab;
+	/* Only one call allowed for modules */
+	if (WARN_ON_ONCE(tab && btf_is_module(btf))) {
+		ret = -EINVAL;
+		goto end;
+	}
+
+	tab_cnt = tab ? tab->cnt : 0;
+	if (tab_cnt > U32_MAX - add_cnt) {
+		ret = -EOVERFLOW;
+		goto end;
+	}
+	if (tab_cnt + add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
+		pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
+		ret = -E2BIG;
+		goto end;
+	}
+
+	tab = krealloc(btf->dtor_kfunc_tab,
+		       offsetof(struct btf_id_dtor_kfunc_tab, dtors[tab_cnt + add_cnt]),
+		       GFP_KERNEL | __GFP_NOWARN);
+	if (!tab) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+	if (!btf->dtor_kfunc_tab)
+		tab->cnt = 0;
+	btf->dtor_kfunc_tab = tab;
+
+	memcpy(tab->dtors + tab->cnt, dtors, add_cnt * sizeof(tab->dtors[0]));
+	tab->cnt += add_cnt;
+
+	sort(tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func, NULL);
+
+end:
+	if (ret)
+		btf_free_dtor_kfunc_tab(btf);
+	btf_put(btf);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_btf_id_dtor_kfuncs);
+
+#define MAX_TYPES_ARE_COMPAT_DEPTH 2
+
+/* Check local and target types for compatibility. This check is used for
+ * type-based CO-RE relocations and follow slightly different rules than
+ * field-based relocations. This function assumes that root types were already
+ * checked for name match. Beyond that initial root-level name check, names
+ * are completely ignored. Compatibility rules are as follows:
+ *   - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs/ENUM64s are considered compatible, but
+ *     kind should match for local and target types (i.e., STRUCT is not
+ *     compatible with UNION);
+ *   - for ENUMs/ENUM64s, the size is ignored;
+ *   - for INT, size and signedness are ignored;
+ *   - for ARRAY, dimensionality is ignored, element types are checked for
+ *     compatibility recursively;
+ *   - CONST/VOLATILE/RESTRICT modifiers are ignored;
+ *   - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
+ *   - FUNC_PROTOs are compatible if they have compatible signature: same
+ *     number of input args and compatible return and argument types.
+ * These rules are not set in stone and probably will be adjusted as we get
+ * more experience with using BPF CO-RE relocations.
+ */
+int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
+			      const struct btf *targ_btf, __u32 targ_id)
+{
+	return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id,
+					   MAX_TYPES_ARE_COMPAT_DEPTH);
+}
+
+#define MAX_TYPES_MATCH_DEPTH 2
+
+int bpf_core_types_match(const struct btf *local_btf, u32 local_id,
+			 const struct btf *targ_btf, u32 targ_id)
+{
+	return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false,
+				      MAX_TYPES_MATCH_DEPTH);
+}
+
+static bool bpf_core_is_flavor_sep(const char *s)
+{
+	/* check X___Y name pattern, where X and Y are not underscores */
+	return s[0] != '_' &&				      /* X */
+	       s[1] == '_' && s[2] == '_' && s[3] == '_' &&   /* ___ */
+	       s[4] != '_';				      /* Y */
+}
+
+size_t bpf_core_essential_name_len(const char *name)
+{
+	size_t n = strlen(name);
+	int i;
+
+	for (i = n - 5; i >= 0; i--) {
+		if (bpf_core_is_flavor_sep(name + i))
+			return i + 1;
+	}
+	return n;
+}
+
+struct bpf_cand_cache {
+	const char *name;
+	u32 name_len;
+	u16 kind;
+	u16 cnt;
+	struct {
+		const struct btf *btf;
+		u32 id;
+	} cands[];
+};
+
+static void bpf_free_cands(struct bpf_cand_cache *cands)
+{
+	if (!cands->cnt)
+		/* empty candidate array was allocated on stack */
+		return;
+	kfree(cands);
+}
+
+static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
+{
+	kfree(cands->name);
+	kfree(cands);
+}
+
+#define VMLINUX_CAND_CACHE_SIZE 31
+static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
+
+#define MODULE_CAND_CACHE_SIZE 31
+static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
+
+static DEFINE_MUTEX(cand_cache_mutex);
+
+static void __print_cand_cache(struct bpf_verifier_log *log,
+			       struct bpf_cand_cache **cache,
+			       int cache_size)
+{
+	struct bpf_cand_cache *cc;
+	int i, j;
+
+	for (i = 0; i < cache_size; i++) {
+		cc = cache[i];
+		if (!cc)
+			continue;
+		bpf_log(log, "[%d]%s(", i, cc->name);
+		for (j = 0; j < cc->cnt; j++) {
+			bpf_log(log, "%d", cc->cands[j].id);
+			if (j < cc->cnt - 1)
+				bpf_log(log, " ");
+		}
+		bpf_log(log, "), ");
+	}
+}
+
+static void print_cand_cache(struct bpf_verifier_log *log)
+{
+	mutex_lock(&cand_cache_mutex);
+	bpf_log(log, "vmlinux_cand_cache:");
+	__print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
+	bpf_log(log, "\nmodule_cand_cache:");
+	__print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
+	bpf_log(log, "\n");
+	mutex_unlock(&cand_cache_mutex);
+}
+
+static u32 hash_cands(struct bpf_cand_cache *cands)
+{
+	return jhash(cands->name, cands->name_len, 0);
+}
+
+static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
+					       struct bpf_cand_cache **cache,
+					       int cache_size)
+{
+	struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
+
+	if (cc && cc->name_len == cands->name_len &&
+	    !strncmp(cc->name, cands->name, cands->name_len))
+		return cc;
+	return NULL;
+}
+
+static size_t sizeof_cands(int cnt)
+{
+	return offsetof(struct bpf_cand_cache, cands[cnt]);
+}
+
+static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
+						  struct bpf_cand_cache **cache,
+						  int cache_size)
+{
+	struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
+
+	if (*cc) {
+		bpf_free_cands_from_cache(*cc);
+		*cc = NULL;
+	}
+	new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL);
+	if (!new_cands) {
+		bpf_free_cands(cands);
+		return ERR_PTR(-ENOMEM);
+	}
+	/* strdup the name, since it will stay in cache.
+	 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
+	 */
+	new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL);
+	bpf_free_cands(cands);
+	if (!new_cands->name) {
+		kfree(new_cands);
+		return ERR_PTR(-ENOMEM);
+	}
+	*cc = new_cands;
+	return new_cands;
+}
+
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
+			       int cache_size)
+{
+	struct bpf_cand_cache *cc;
+	int i, j;
+
+	for (i = 0; i < cache_size; i++) {
+		cc = cache[i];
+		if (!cc)
+			continue;
+		if (!btf) {
+			/* when new module is loaded purge all of module_cand_cache,
+			 * since new module might have candidates with the name
+			 * that matches cached cands.
+			 */
+			bpf_free_cands_from_cache(cc);
+			cache[i] = NULL;
+			continue;
+		}
+		/* when module is unloaded purge cache entries
+		 * that match module's btf
+		 */
+		for (j = 0; j < cc->cnt; j++)
+			if (cc->cands[j].btf == btf) {
+				bpf_free_cands_from_cache(cc);
+				cache[i] = NULL;
+				break;
+			}
+	}
+
+}
+
+static void purge_cand_cache(struct btf *btf)
+{
+	mutex_lock(&cand_cache_mutex);
+	__purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
+	mutex_unlock(&cand_cache_mutex);
+}
+#endif
+
+static struct bpf_cand_cache *
+bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
+		   int targ_start_id)
+{
+	struct bpf_cand_cache *new_cands;
+	const struct btf_type *t;
+	const char *targ_name;
+	size_t targ_essent_len;
+	int n, i;
+
+	n = btf_nr_types(targ_btf);
+	for (i = targ_start_id; i < n; i++) {
+		t = btf_type_by_id(targ_btf, i);
+		if (btf_kind(t) != cands->kind)
+			continue;
+
+		targ_name = btf_name_by_offset(targ_btf, t->name_off);
+		if (!targ_name)
+			continue;
+
+		/* the resched point is before strncmp to make sure that search
+		 * for non-existing name will have a chance to schedule().
+		 */
+		cond_resched();
+
+		if (strncmp(cands->name, targ_name, cands->name_len) != 0)
+			continue;
+
+		targ_essent_len = bpf_core_essential_name_len(targ_name);
+		if (targ_essent_len != cands->name_len)
+			continue;
+
+		/* most of the time there is only one candidate for a given kind+name pair */
+		new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL);
+		if (!new_cands) {
+			bpf_free_cands(cands);
+			return ERR_PTR(-ENOMEM);
+		}
+
+		memcpy(new_cands, cands, sizeof_cands(cands->cnt));
+		bpf_free_cands(cands);
+		cands = new_cands;
+		cands->cands[cands->cnt].btf = targ_btf;
+		cands->cands[cands->cnt].id = i;
+		cands->cnt++;
+	}
+	return cands;
+}
+
+static struct bpf_cand_cache *
+bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
+{
+	struct bpf_cand_cache *cands, *cc, local_cand = {};
+	const struct btf *local_btf = ctx->btf;
+	const struct btf_type *local_type;
+	const struct btf *main_btf;
+	size_t local_essent_len;
+	struct btf *mod_btf;
+	const char *name;
+	int id;
+
+	main_btf = bpf_get_btf_vmlinux();
+	if (IS_ERR(main_btf))
+		return ERR_CAST(main_btf);
+	if (!main_btf)
+		return ERR_PTR(-EINVAL);
+
+	local_type = btf_type_by_id(local_btf, local_type_id);
+	if (!local_type)
+		return ERR_PTR(-EINVAL);
+
+	name = btf_name_by_offset(local_btf, local_type->name_off);
+	if (str_is_empty(name))
+		return ERR_PTR(-EINVAL);
+	local_essent_len = bpf_core_essential_name_len(name);
+
+	cands = &local_cand;
+	cands->name = name;
+	cands->kind = btf_kind(local_type);
+	cands->name_len = local_essent_len;
+
+	cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
+	/* cands is a pointer to stack here */
+	if (cc) {
+		if (cc->cnt)
+			return cc;
+		goto check_modules;
+	}
+
+	/* Attempt to find target candidates in vmlinux BTF first */
+	cands = bpf_core_add_cands(cands, main_btf, 1);
+	if (IS_ERR(cands))
+		return ERR_CAST(cands);
+
+	/* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
+
+	/* populate cache even when cands->cnt == 0 */
+	cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
+	if (IS_ERR(cc))
+		return ERR_CAST(cc);
+
+	/* if vmlinux BTF has any candidate, don't go for module BTFs */
+	if (cc->cnt)
+		return cc;
+
+check_modules:
+	/* cands is a pointer to stack here and cands->cnt == 0 */
+	cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
+	if (cc)
+		/* if cache has it return it even if cc->cnt == 0 */
+		return cc;
+
+	/* If candidate is not found in vmlinux's BTF then search in module's BTFs */
+	spin_lock_bh(&btf_idr_lock);
+	idr_for_each_entry(&btf_idr, mod_btf, id) {
+		if (!btf_is_module(mod_btf))
+			continue;
+		/* linear search could be slow hence unlock/lock
+		 * the IDR to avoiding holding it for too long
+		 */
+		btf_get(mod_btf);
+		spin_unlock_bh(&btf_idr_lock);
+		cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
+		btf_put(mod_btf);
+		if (IS_ERR(cands))
+			return ERR_CAST(cands);
+		spin_lock_bh(&btf_idr_lock);
+	}
+	spin_unlock_bh(&btf_idr_lock);
+	/* cands is a pointer to kmalloced memory here if cands->cnt > 0
+	 * or pointer to stack if cands->cnd == 0.
+	 * Copy it into the cache even when cands->cnt == 0 and
+	 * return the result.
+	 */
+	return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
+}
+
+int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
+		   int relo_idx, void *insn)
+{
+	bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
+	struct bpf_core_cand_list cands = {};
+	struct bpf_core_relo_res targ_res;
+	struct bpf_core_spec *specs;
+	int err;
+
+	/* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
+	 * into arrays of btf_ids of struct fields and array indices.
+	 */
+	specs = kcalloc(3, sizeof(*specs), GFP_KERNEL);
+	if (!specs)
+		return -ENOMEM;
+
+	if (need_cands) {
+		struct bpf_cand_cache *cc;
+		int i;
+
+		mutex_lock(&cand_cache_mutex);
+		cc = bpf_core_find_cands(ctx, relo->type_id);
+		if (IS_ERR(cc)) {
+			bpf_log(ctx->log, "target candidate search failed for %d\n",
+				relo->type_id);
+			err = PTR_ERR(cc);
+			goto out;
+		}
+		if (cc->cnt) {
+			cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL);
+			if (!cands.cands) {
+				err = -ENOMEM;
+				goto out;
+			}
+		}
+		for (i = 0; i < cc->cnt; i++) {
+			bpf_log(ctx->log,
+				"CO-RE relocating %s %s: found target candidate [%d]\n",
+				btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
+			cands.cands[i].btf = cc->cands[i].btf;
+			cands.cands[i].id = cc->cands[i].id;
+		}
+		cands.len = cc->cnt;
+		/* cand_cache_mutex needs to span the cache lookup and
+		 * copy of btf pointer into bpf_core_cand_list,
+		 * since module can be unloaded while bpf_core_calc_relo_insn
+		 * is working with module's btf.
+		 */
+	}
+
+	err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
+				      &targ_res);
+	if (err)
+		goto out;
+
+	err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
+				  &targ_res);
+
+out:
+	kfree(specs);
+	if (need_cands) {
+		kfree(cands.cands);
+		mutex_unlock(&cand_cache_mutex);
+		if (ctx->log->level & BPF_LOG_LEVEL2)
+			print_cand_cache(ctx->log);
+	}
+	return err;
+}
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
new file mode 100644
index 000000000..bb70f400c
--- /dev/null
+++ b/kernel/bpf/cgroup.c
@@ -0,0 +1,2561 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Functions to manage eBPF programs attached to cgroups
+ *
+ * Copyright (c) 2016 Daniel Mack
+ */
+
+#include <linux/kernel.h>
+#include <linux/atomic.h>
+#include <linux/cgroup.h>
+#include <linux/filter.h>
+#include <linux/slab.h>
+#include <linux/sysctl.h>
+#include <linux/string.h>
+#include <linux/bpf.h>
+#include <linux/bpf-cgroup.h>
+#include <linux/bpf_lsm.h>
+#include <linux/bpf_verifier.h>
+#include <net/sock.h>
+#include <net/bpf_sk_storage.h>
+
+#include "../cgroup/cgroup-internal.h"
+
+DEFINE_STATIC_KEY_ARRAY_FALSE(cgroup_bpf_enabled_key, MAX_CGROUP_BPF_ATTACH_TYPE);
+EXPORT_SYMBOL(cgroup_bpf_enabled_key);
+
+/* __always_inline is necessary to prevent indirect call through run_prog
+ * function pointer.
+ */
+static __always_inline int
+bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
+		      enum cgroup_bpf_attach_type atype,
+		      const void *ctx, bpf_prog_run_fn run_prog,
+		      int retval, u32 *ret_flags)
+{
+	const struct bpf_prog_array_item *item;
+	const struct bpf_prog *prog;
+	const struct bpf_prog_array *array;
+	struct bpf_run_ctx *old_run_ctx;
+	struct bpf_cg_run_ctx run_ctx;
+	u32 func_ret;
+
+	run_ctx.retval = retval;
+	migrate_disable();
+	rcu_read_lock();
+	array = rcu_dereference(cgrp->effective[atype]);
+	item = &array->items[0];
+	old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
+	while ((prog = READ_ONCE(item->prog))) {
+		run_ctx.prog_item = item;
+		func_ret = run_prog(prog, ctx);
+		if (ret_flags) {
+			*(ret_flags) |= (func_ret >> 1);
+			func_ret &= 1;
+		}
+		if (!func_ret && !IS_ERR_VALUE((long)run_ctx.retval))
+			run_ctx.retval = -EPERM;
+		item++;
+	}
+	bpf_reset_run_ctx(old_run_ctx);
+	rcu_read_unlock();
+	migrate_enable();
+	return run_ctx.retval;
+}
+
+unsigned int __cgroup_bpf_run_lsm_sock(const void *ctx,
+				       const struct bpf_insn *insn)
+{
+	const struct bpf_prog *shim_prog;
+	struct sock *sk;
+	struct cgroup *cgrp;
+	int ret = 0;
+	u64 *args;
+
+	args = (u64 *)ctx;
+	sk = (void *)(unsigned long)args[0];
+	/*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/
+	shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi));
+
+	cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	if (likely(cgrp))
+		ret = bpf_prog_run_array_cg(&cgrp->bpf,
+					    shim_prog->aux->cgroup_atype,
+					    ctx, bpf_prog_run, 0, NULL);
+	return ret;
+}
+
+unsigned int __cgroup_bpf_run_lsm_socket(const void *ctx,
+					 const struct bpf_insn *insn)
+{
+	const struct bpf_prog *shim_prog;
+	struct socket *sock;
+	struct cgroup *cgrp;
+	int ret = 0;
+	u64 *args;
+
+	args = (u64 *)ctx;
+	sock = (void *)(unsigned long)args[0];
+	/*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/
+	shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi));
+
+	cgrp = sock_cgroup_ptr(&sock->sk->sk_cgrp_data);
+	if (likely(cgrp))
+		ret = bpf_prog_run_array_cg(&cgrp->bpf,
+					    shim_prog->aux->cgroup_atype,
+					    ctx, bpf_prog_run, 0, NULL);
+	return ret;
+}
+
+unsigned int __cgroup_bpf_run_lsm_current(const void *ctx,
+					  const struct bpf_insn *insn)
+{
+	const struct bpf_prog *shim_prog;
+	struct cgroup *cgrp;
+	int ret = 0;
+
+	/*shim_prog = container_of(insn, struct bpf_prog, insnsi);*/
+	shim_prog = (const struct bpf_prog *)((void *)insn - offsetof(struct bpf_prog, insnsi));
+
+	/* We rely on trampoline's __bpf_prog_enter_lsm_cgroup to grab RCU read lock. */
+	cgrp = task_dfl_cgroup(current);
+	if (likely(cgrp))
+		ret = bpf_prog_run_array_cg(&cgrp->bpf,
+					    shim_prog->aux->cgroup_atype,
+					    ctx, bpf_prog_run, 0, NULL);
+	return ret;
+}
+
+#ifdef CONFIG_BPF_LSM
+struct cgroup_lsm_atype {
+	u32 attach_btf_id;
+	int refcnt;
+};
+
+static struct cgroup_lsm_atype cgroup_lsm_atype[CGROUP_LSM_NUM];
+
+static enum cgroup_bpf_attach_type
+bpf_cgroup_atype_find(enum bpf_attach_type attach_type, u32 attach_btf_id)
+{
+	int i;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	if (attach_type != BPF_LSM_CGROUP)
+		return to_cgroup_bpf_attach_type(attach_type);
+
+	for (i = 0; i < ARRAY_SIZE(cgroup_lsm_atype); i++)
+		if (cgroup_lsm_atype[i].attach_btf_id == attach_btf_id)
+			return CGROUP_LSM_START + i;
+
+	for (i = 0; i < ARRAY_SIZE(cgroup_lsm_atype); i++)
+		if (cgroup_lsm_atype[i].attach_btf_id == 0)
+			return CGROUP_LSM_START + i;
+
+	return -E2BIG;
+
+}
+
+void bpf_cgroup_atype_get(u32 attach_btf_id, int cgroup_atype)
+{
+	int i = cgroup_atype - CGROUP_LSM_START;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	WARN_ON_ONCE(cgroup_lsm_atype[i].attach_btf_id &&
+		     cgroup_lsm_atype[i].attach_btf_id != attach_btf_id);
+
+	cgroup_lsm_atype[i].attach_btf_id = attach_btf_id;
+	cgroup_lsm_atype[i].refcnt++;
+}
+
+void bpf_cgroup_atype_put(int cgroup_atype)
+{
+	int i = cgroup_atype - CGROUP_LSM_START;
+
+	cgroup_lock();
+	if (--cgroup_lsm_atype[i].refcnt <= 0)
+		cgroup_lsm_atype[i].attach_btf_id = 0;
+	WARN_ON_ONCE(cgroup_lsm_atype[i].refcnt < 0);
+	cgroup_unlock();
+}
+#else
+static enum cgroup_bpf_attach_type
+bpf_cgroup_atype_find(enum bpf_attach_type attach_type, u32 attach_btf_id)
+{
+	if (attach_type != BPF_LSM_CGROUP)
+		return to_cgroup_bpf_attach_type(attach_type);
+	return -EOPNOTSUPP;
+}
+#endif /* CONFIG_BPF_LSM */
+
+void cgroup_bpf_offline(struct cgroup *cgrp)
+{
+	cgroup_get(cgrp);
+	percpu_ref_kill(&cgrp->bpf.refcnt);
+}
+
+static void bpf_cgroup_storages_free(struct bpf_cgroup_storage *storages[])
+{
+	enum bpf_cgroup_storage_type stype;
+
+	for_each_cgroup_storage_type(stype)
+		bpf_cgroup_storage_free(storages[stype]);
+}
+
+static int bpf_cgroup_storages_alloc(struct bpf_cgroup_storage *storages[],
+				     struct bpf_cgroup_storage *new_storages[],
+				     enum bpf_attach_type type,
+				     struct bpf_prog *prog,
+				     struct cgroup *cgrp)
+{
+	enum bpf_cgroup_storage_type stype;
+	struct bpf_cgroup_storage_key key;
+	struct bpf_map *map;
+
+	key.cgroup_inode_id = cgroup_id(cgrp);
+	key.attach_type = type;
+
+	for_each_cgroup_storage_type(stype) {
+		map = prog->aux->cgroup_storage[stype];
+		if (!map)
+			continue;
+
+		storages[stype] = cgroup_storage_lookup((void *)map, &key, false);
+		if (storages[stype])
+			continue;
+
+		storages[stype] = bpf_cgroup_storage_alloc(prog, stype);
+		if (IS_ERR(storages[stype])) {
+			bpf_cgroup_storages_free(new_storages);
+			return -ENOMEM;
+		}
+
+		new_storages[stype] = storages[stype];
+	}
+
+	return 0;
+}
+
+static void bpf_cgroup_storages_assign(struct bpf_cgroup_storage *dst[],
+				       struct bpf_cgroup_storage *src[])
+{
+	enum bpf_cgroup_storage_type stype;
+
+	for_each_cgroup_storage_type(stype)
+		dst[stype] = src[stype];
+}
+
+static void bpf_cgroup_storages_link(struct bpf_cgroup_storage *storages[],
+				     struct cgroup *cgrp,
+				     enum bpf_attach_type attach_type)
+{
+	enum bpf_cgroup_storage_type stype;
+
+	for_each_cgroup_storage_type(stype)
+		bpf_cgroup_storage_link(storages[stype], cgrp, attach_type);
+}
+
+/* Called when bpf_cgroup_link is auto-detached from dying cgroup.
+ * It drops cgroup and bpf_prog refcounts, and marks bpf_link as defunct. It
+ * doesn't free link memory, which will eventually be done by bpf_link's
+ * release() callback, when its last FD is closed.
+ */
+static void bpf_cgroup_link_auto_detach(struct bpf_cgroup_link *link)
+{
+	cgroup_put(link->cgroup);
+	link->cgroup = NULL;
+}
+
+/**
+ * cgroup_bpf_release() - put references of all bpf programs and
+ *                        release all cgroup bpf data
+ * @work: work structure embedded into the cgroup to modify
+ */
+static void cgroup_bpf_release(struct work_struct *work)
+{
+	struct cgroup *p, *cgrp = container_of(work, struct cgroup,
+					       bpf.release_work);
+	struct bpf_prog_array *old_array;
+	struct list_head *storages = &cgrp->bpf.storages;
+	struct bpf_cgroup_storage *storage, *stmp;
+
+	unsigned int atype;
+
+	cgroup_lock();
+
+	for (atype = 0; atype < ARRAY_SIZE(cgrp->bpf.progs); atype++) {
+		struct hlist_head *progs = &cgrp->bpf.progs[atype];
+		struct bpf_prog_list *pl;
+		struct hlist_node *pltmp;
+
+		hlist_for_each_entry_safe(pl, pltmp, progs, node) {
+			hlist_del(&pl->node);
+			if (pl->prog) {
+				if (pl->prog->expected_attach_type == BPF_LSM_CGROUP)
+					bpf_trampoline_unlink_cgroup_shim(pl->prog);
+				bpf_prog_put(pl->prog);
+			}
+			if (pl->link) {
+				if (pl->link->link.prog->expected_attach_type == BPF_LSM_CGROUP)
+					bpf_trampoline_unlink_cgroup_shim(pl->link->link.prog);
+				bpf_cgroup_link_auto_detach(pl->link);
+			}
+			kfree(pl);
+			static_branch_dec(&cgroup_bpf_enabled_key[atype]);
+		}
+		old_array = rcu_dereference_protected(
+				cgrp->bpf.effective[atype],
+				lockdep_is_held(&cgroup_mutex));
+		bpf_prog_array_free(old_array);
+	}
+
+	list_for_each_entry_safe(storage, stmp, storages, list_cg) {
+		bpf_cgroup_storage_unlink(storage);
+		bpf_cgroup_storage_free(storage);
+	}
+
+	cgroup_unlock();
+
+	for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
+		cgroup_bpf_put(p);
+
+	percpu_ref_exit(&cgrp->bpf.refcnt);
+	cgroup_put(cgrp);
+}
+
+/**
+ * cgroup_bpf_release_fn() - callback used to schedule releasing
+ *                           of bpf cgroup data
+ * @ref: percpu ref counter structure
+ */
+static void cgroup_bpf_release_fn(struct percpu_ref *ref)
+{
+	struct cgroup *cgrp = container_of(ref, struct cgroup, bpf.refcnt);
+
+	INIT_WORK(&cgrp->bpf.release_work, cgroup_bpf_release);
+	queue_work(system_wq, &cgrp->bpf.release_work);
+}
+
+/* Get underlying bpf_prog of bpf_prog_list entry, regardless if it's through
+ * link or direct prog.
+ */
+static struct bpf_prog *prog_list_prog(struct bpf_prog_list *pl)
+{
+	if (pl->prog)
+		return pl->prog;
+	if (pl->link)
+		return pl->link->link.prog;
+	return NULL;
+}
+
+/* count number of elements in the list.
+ * it's slow but the list cannot be long
+ */
+static u32 prog_list_length(struct hlist_head *head)
+{
+	struct bpf_prog_list *pl;
+	u32 cnt = 0;
+
+	hlist_for_each_entry(pl, head, node) {
+		if (!prog_list_prog(pl))
+			continue;
+		cnt++;
+	}
+	return cnt;
+}
+
+/* if parent has non-overridable prog attached,
+ * disallow attaching new programs to the descendent cgroup.
+ * if parent has overridable or multi-prog, allow attaching
+ */
+static bool hierarchy_allows_attach(struct cgroup *cgrp,
+				    enum cgroup_bpf_attach_type atype)
+{
+	struct cgroup *p;
+
+	p = cgroup_parent(cgrp);
+	if (!p)
+		return true;
+	do {
+		u32 flags = p->bpf.flags[atype];
+		u32 cnt;
+
+		if (flags & BPF_F_ALLOW_MULTI)
+			return true;
+		cnt = prog_list_length(&p->bpf.progs[atype]);
+		WARN_ON_ONCE(cnt > 1);
+		if (cnt == 1)
+			return !!(flags & BPF_F_ALLOW_OVERRIDE);
+		p = cgroup_parent(p);
+	} while (p);
+	return true;
+}
+
+/* compute a chain of effective programs for a given cgroup:
+ * start from the list of programs in this cgroup and add
+ * all parent programs.
+ * Note that parent's F_ALLOW_OVERRIDE-type program is yielding
+ * to programs in this cgroup
+ */
+static int compute_effective_progs(struct cgroup *cgrp,
+				   enum cgroup_bpf_attach_type atype,
+				   struct bpf_prog_array **array)
+{
+	struct bpf_prog_array_item *item;
+	struct bpf_prog_array *progs;
+	struct bpf_prog_list *pl;
+	struct cgroup *p = cgrp;
+	int cnt = 0;
+
+	/* count number of effective programs by walking parents */
+	do {
+		if (cnt == 0 || (p->bpf.flags[atype] & BPF_F_ALLOW_MULTI))
+			cnt += prog_list_length(&p->bpf.progs[atype]);
+		p = cgroup_parent(p);
+	} while (p);
+
+	progs = bpf_prog_array_alloc(cnt, GFP_KERNEL);
+	if (!progs)
+		return -ENOMEM;
+
+	/* populate the array with effective progs */
+	cnt = 0;
+	p = cgrp;
+	do {
+		if (cnt > 0 && !(p->bpf.flags[atype] & BPF_F_ALLOW_MULTI))
+			continue;
+
+		hlist_for_each_entry(pl, &p->bpf.progs[atype], node) {
+			if (!prog_list_prog(pl))
+				continue;
+
+			item = &progs->items[cnt];
+			item->prog = prog_list_prog(pl);
+			bpf_cgroup_storages_assign(item->cgroup_storage,
+						   pl->storage);
+			cnt++;
+		}
+	} while ((p = cgroup_parent(p)));
+
+	*array = progs;
+	return 0;
+}
+
+static void activate_effective_progs(struct cgroup *cgrp,
+				     enum cgroup_bpf_attach_type atype,
+				     struct bpf_prog_array *old_array)
+{
+	old_array = rcu_replace_pointer(cgrp->bpf.effective[atype], old_array,
+					lockdep_is_held(&cgroup_mutex));
+	/* free prog array after grace period, since __cgroup_bpf_run_*()
+	 * might be still walking the array
+	 */
+	bpf_prog_array_free(old_array);
+}
+
+/**
+ * cgroup_bpf_inherit() - inherit effective programs from parent
+ * @cgrp: the cgroup to modify
+ */
+int cgroup_bpf_inherit(struct cgroup *cgrp)
+{
+/* has to use marco instead of const int, since compiler thinks
+ * that array below is variable length
+ */
+#define	NR ARRAY_SIZE(cgrp->bpf.effective)
+	struct bpf_prog_array *arrays[NR] = {};
+	struct cgroup *p;
+	int ret, i;
+
+	ret = percpu_ref_init(&cgrp->bpf.refcnt, cgroup_bpf_release_fn, 0,
+			      GFP_KERNEL);
+	if (ret)
+		return ret;
+
+	for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
+		cgroup_bpf_get(p);
+
+	for (i = 0; i < NR; i++)
+		INIT_HLIST_HEAD(&cgrp->bpf.progs[i]);
+
+	INIT_LIST_HEAD(&cgrp->bpf.storages);
+
+	for (i = 0; i < NR; i++)
+		if (compute_effective_progs(cgrp, i, &arrays[i]))
+			goto cleanup;
+
+	for (i = 0; i < NR; i++)
+		activate_effective_progs(cgrp, i, arrays[i]);
+
+	return 0;
+cleanup:
+	for (i = 0; i < NR; i++)
+		bpf_prog_array_free(arrays[i]);
+
+	for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
+		cgroup_bpf_put(p);
+
+	percpu_ref_exit(&cgrp->bpf.refcnt);
+
+	return -ENOMEM;
+}
+
+static int update_effective_progs(struct cgroup *cgrp,
+				  enum cgroup_bpf_attach_type atype)
+{
+	struct cgroup_subsys_state *css;
+	int err;
+
+	/* allocate and recompute effective prog arrays */
+	css_for_each_descendant_pre(css, &cgrp->self) {
+		struct cgroup *desc = container_of(css, struct cgroup, self);
+
+		if (percpu_ref_is_zero(&desc->bpf.refcnt))
+			continue;
+
+		err = compute_effective_progs(desc, atype, &desc->bpf.inactive);
+		if (err)
+			goto cleanup;
+	}
+
+	/* all allocations were successful. Activate all prog arrays */
+	css_for_each_descendant_pre(css, &cgrp->self) {
+		struct cgroup *desc = container_of(css, struct cgroup, self);
+
+		if (percpu_ref_is_zero(&desc->bpf.refcnt)) {
+			if (unlikely(desc->bpf.inactive)) {
+				bpf_prog_array_free(desc->bpf.inactive);
+				desc->bpf.inactive = NULL;
+			}
+			continue;
+		}
+
+		activate_effective_progs(desc, atype, desc->bpf.inactive);
+		desc->bpf.inactive = NULL;
+	}
+
+	return 0;
+
+cleanup:
+	/* oom while computing effective. Free all computed effective arrays
+	 * since they were not activated
+	 */
+	css_for_each_descendant_pre(css, &cgrp->self) {
+		struct cgroup *desc = container_of(css, struct cgroup, self);
+
+		bpf_prog_array_free(desc->bpf.inactive);
+		desc->bpf.inactive = NULL;
+	}
+
+	return err;
+}
+
+#define BPF_CGROUP_MAX_PROGS 64
+
+static struct bpf_prog_list *find_attach_entry(struct hlist_head *progs,
+					       struct bpf_prog *prog,
+					       struct bpf_cgroup_link *link,
+					       struct bpf_prog *replace_prog,
+					       bool allow_multi)
+{
+	struct bpf_prog_list *pl;
+
+	/* single-attach case */
+	if (!allow_multi) {
+		if (hlist_empty(progs))
+			return NULL;
+		return hlist_entry(progs->first, typeof(*pl), node);
+	}
+
+	hlist_for_each_entry(pl, progs, node) {
+		if (prog && pl->prog == prog && prog != replace_prog)
+			/* disallow attaching the same prog twice */
+			return ERR_PTR(-EINVAL);
+		if (link && pl->link == link)
+			/* disallow attaching the same link twice */
+			return ERR_PTR(-EINVAL);
+	}
+
+	/* direct prog multi-attach w/ replacement case */
+	if (replace_prog) {
+		hlist_for_each_entry(pl, progs, node) {
+			if (pl->prog == replace_prog)
+				/* a match found */
+				return pl;
+		}
+		/* prog to replace not found for cgroup */
+		return ERR_PTR(-ENOENT);
+	}
+
+	return NULL;
+}
+
+/**
+ * __cgroup_bpf_attach() - Attach the program or the link to a cgroup, and
+ *                         propagate the change to descendants
+ * @cgrp: The cgroup which descendants to traverse
+ * @prog: A program to attach
+ * @link: A link to attach
+ * @replace_prog: Previously attached program to replace if BPF_F_REPLACE is set
+ * @type: Type of attach operation
+ * @flags: Option flags
+ *
+ * Exactly one of @prog or @link can be non-null.
+ * Must be called with cgroup_mutex held.
+ */
+static int __cgroup_bpf_attach(struct cgroup *cgrp,
+			       struct bpf_prog *prog, struct bpf_prog *replace_prog,
+			       struct bpf_cgroup_link *link,
+			       enum bpf_attach_type type, u32 flags)
+{
+	u32 saved_flags = (flags & (BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI));
+	struct bpf_prog *old_prog = NULL;
+	struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {};
+	struct bpf_cgroup_storage *new_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {};
+	struct bpf_prog *new_prog = prog ? : link->link.prog;
+	enum cgroup_bpf_attach_type atype;
+	struct bpf_prog_list *pl;
+	struct hlist_head *progs;
+	int err;
+
+	if (((flags & BPF_F_ALLOW_OVERRIDE) && (flags & BPF_F_ALLOW_MULTI)) ||
+	    ((flags & BPF_F_REPLACE) && !(flags & BPF_F_ALLOW_MULTI)))
+		/* invalid combination */
+		return -EINVAL;
+	if (link && (prog || replace_prog))
+		/* only either link or prog/replace_prog can be specified */
+		return -EINVAL;
+	if (!!replace_prog != !!(flags & BPF_F_REPLACE))
+		/* replace_prog implies BPF_F_REPLACE, and vice versa */
+		return -EINVAL;
+
+	atype = bpf_cgroup_atype_find(type, new_prog->aux->attach_btf_id);
+	if (atype < 0)
+		return -EINVAL;
+
+	progs = &cgrp->bpf.progs[atype];
+
+	if (!hierarchy_allows_attach(cgrp, atype))
+		return -EPERM;
+
+	if (!hlist_empty(progs) && cgrp->bpf.flags[atype] != saved_flags)
+		/* Disallow attaching non-overridable on top
+		 * of existing overridable in this cgroup.
+		 * Disallow attaching multi-prog if overridable or none
+		 */
+		return -EPERM;
+
+	if (prog_list_length(progs) >= BPF_CGROUP_MAX_PROGS)
+		return -E2BIG;
+
+	pl = find_attach_entry(progs, prog, link, replace_prog,
+			       flags & BPF_F_ALLOW_MULTI);
+	if (IS_ERR(pl))
+		return PTR_ERR(pl);
+
+	if (bpf_cgroup_storages_alloc(storage, new_storage, type,
+				      prog ? : link->link.prog, cgrp))
+		return -ENOMEM;
+
+	if (pl) {
+		old_prog = pl->prog;
+	} else {
+		struct hlist_node *last = NULL;
+
+		pl = kmalloc(sizeof(*pl), GFP_KERNEL);
+		if (!pl) {
+			bpf_cgroup_storages_free(new_storage);
+			return -ENOMEM;
+		}
+		if (hlist_empty(progs))
+			hlist_add_head(&pl->node, progs);
+		else
+			hlist_for_each(last, progs) {
+				if (last->next)
+					continue;
+				hlist_add_behind(&pl->node, last);
+				break;
+			}
+	}
+
+	pl->prog = prog;
+	pl->link = link;
+	bpf_cgroup_storages_assign(pl->storage, storage);
+	cgrp->bpf.flags[atype] = saved_flags;
+
+	if (type == BPF_LSM_CGROUP) {
+		err = bpf_trampoline_link_cgroup_shim(new_prog, atype);
+		if (err)
+			goto cleanup;
+	}
+
+	err = update_effective_progs(cgrp, atype);
+	if (err)
+		goto cleanup_trampoline;
+
+	if (old_prog) {
+		if (type == BPF_LSM_CGROUP)
+			bpf_trampoline_unlink_cgroup_shim(old_prog);
+		bpf_prog_put(old_prog);
+	} else {
+		static_branch_inc(&cgroup_bpf_enabled_key[atype]);
+	}
+	bpf_cgroup_storages_link(new_storage, cgrp, type);
+	return 0;
+
+cleanup_trampoline:
+	if (type == BPF_LSM_CGROUP)
+		bpf_trampoline_unlink_cgroup_shim(new_prog);
+
+cleanup:
+	if (old_prog) {
+		pl->prog = old_prog;
+		pl->link = NULL;
+	}
+	bpf_cgroup_storages_free(new_storage);
+	if (!old_prog) {
+		hlist_del(&pl->node);
+		kfree(pl);
+	}
+	return err;
+}
+
+static int cgroup_bpf_attach(struct cgroup *cgrp,
+			     struct bpf_prog *prog, struct bpf_prog *replace_prog,
+			     struct bpf_cgroup_link *link,
+			     enum bpf_attach_type type,
+			     u32 flags)
+{
+	int ret;
+
+	cgroup_lock();
+	ret = __cgroup_bpf_attach(cgrp, prog, replace_prog, link, type, flags);
+	cgroup_unlock();
+	return ret;
+}
+
+/* Swap updated BPF program for given link in effective program arrays across
+ * all descendant cgroups. This function is guaranteed to succeed.
+ */
+static void replace_effective_prog(struct cgroup *cgrp,
+				   enum cgroup_bpf_attach_type atype,
+				   struct bpf_cgroup_link *link)
+{
+	struct bpf_prog_array_item *item;
+	struct cgroup_subsys_state *css;
+	struct bpf_prog_array *progs;
+	struct bpf_prog_list *pl;
+	struct hlist_head *head;
+	struct cgroup *cg;
+	int pos;
+
+	css_for_each_descendant_pre(css, &cgrp->self) {
+		struct cgroup *desc = container_of(css, struct cgroup, self);
+
+		if (percpu_ref_is_zero(&desc->bpf.refcnt))
+			continue;
+
+		/* find position of link in effective progs array */
+		for (pos = 0, cg = desc; cg; cg = cgroup_parent(cg)) {
+			if (pos && !(cg->bpf.flags[atype] & BPF_F_ALLOW_MULTI))
+				continue;
+
+			head = &cg->bpf.progs[atype];
+			hlist_for_each_entry(pl, head, node) {
+				if (!prog_list_prog(pl))
+					continue;
+				if (pl->link == link)
+					goto found;
+				pos++;
+			}
+		}
+found:
+		BUG_ON(!cg);
+		progs = rcu_dereference_protected(
+				desc->bpf.effective[atype],
+				lockdep_is_held(&cgroup_mutex));
+		item = &progs->items[pos];
+		WRITE_ONCE(item->prog, link->link.prog);
+	}
+}
+
+/**
+ * __cgroup_bpf_replace() - Replace link's program and propagate the change
+ *                          to descendants
+ * @cgrp: The cgroup which descendants to traverse
+ * @link: A link for which to replace BPF program
+ * @type: Type of attach operation
+ *
+ * Must be called with cgroup_mutex held.
+ */
+static int __cgroup_bpf_replace(struct cgroup *cgrp,
+				struct bpf_cgroup_link *link,
+				struct bpf_prog *new_prog)
+{
+	enum cgroup_bpf_attach_type atype;
+	struct bpf_prog *old_prog;
+	struct bpf_prog_list *pl;
+	struct hlist_head *progs;
+	bool found = false;
+
+	atype = bpf_cgroup_atype_find(link->type, new_prog->aux->attach_btf_id);
+	if (atype < 0)
+		return -EINVAL;
+
+	progs = &cgrp->bpf.progs[atype];
+
+	if (link->link.prog->type != new_prog->type)
+		return -EINVAL;
+
+	hlist_for_each_entry(pl, progs, node) {
+		if (pl->link == link) {
+			found = true;
+			break;
+		}
+	}
+	if (!found)
+		return -ENOENT;
+
+	old_prog = xchg(&link->link.prog, new_prog);
+	replace_effective_prog(cgrp, atype, link);
+	bpf_prog_put(old_prog);
+	return 0;
+}
+
+static int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *new_prog,
+			      struct bpf_prog *old_prog)
+{
+	struct bpf_cgroup_link *cg_link;
+	int ret;
+
+	cg_link = container_of(link, struct bpf_cgroup_link, link);
+
+	cgroup_lock();
+	/* link might have been auto-released by dying cgroup, so fail */
+	if (!cg_link->cgroup) {
+		ret = -ENOLINK;
+		goto out_unlock;
+	}
+	if (old_prog && link->prog != old_prog) {
+		ret = -EPERM;
+		goto out_unlock;
+	}
+	ret = __cgroup_bpf_replace(cg_link->cgroup, cg_link, new_prog);
+out_unlock:
+	cgroup_unlock();
+	return ret;
+}
+
+static struct bpf_prog_list *find_detach_entry(struct hlist_head *progs,
+					       struct bpf_prog *prog,
+					       struct bpf_cgroup_link *link,
+					       bool allow_multi)
+{
+	struct bpf_prog_list *pl;
+
+	if (!allow_multi) {
+		if (hlist_empty(progs))
+			/* report error when trying to detach and nothing is attached */
+			return ERR_PTR(-ENOENT);
+
+		/* to maintain backward compatibility NONE and OVERRIDE cgroups
+		 * allow detaching with invalid FD (prog==NULL) in legacy mode
+		 */
+		return hlist_entry(progs->first, typeof(*pl), node);
+	}
+
+	if (!prog && !link)
+		/* to detach MULTI prog the user has to specify valid FD
+		 * of the program or link to be detached
+		 */
+		return ERR_PTR(-EINVAL);
+
+	/* find the prog or link and detach it */
+	hlist_for_each_entry(pl, progs, node) {
+		if (pl->prog == prog && pl->link == link)
+			return pl;
+	}
+	return ERR_PTR(-ENOENT);
+}
+
+/**
+ * purge_effective_progs() - After compute_effective_progs fails to alloc new
+ *                           cgrp->bpf.inactive table we can recover by
+ *                           recomputing the array in place.
+ *
+ * @cgrp: The cgroup which descendants to travers
+ * @prog: A program to detach or NULL
+ * @link: A link to detach or NULL
+ * @atype: Type of detach operation
+ */
+static void purge_effective_progs(struct cgroup *cgrp, struct bpf_prog *prog,
+				  struct bpf_cgroup_link *link,
+				  enum cgroup_bpf_attach_type atype)
+{
+	struct cgroup_subsys_state *css;
+	struct bpf_prog_array *progs;
+	struct bpf_prog_list *pl;
+	struct hlist_head *head;
+	struct cgroup *cg;
+	int pos;
+
+	/* recompute effective prog array in place */
+	css_for_each_descendant_pre(css, &cgrp->self) {
+		struct cgroup *desc = container_of(css, struct cgroup, self);
+
+		if (percpu_ref_is_zero(&desc->bpf.refcnt))
+			continue;
+
+		/* find position of link or prog in effective progs array */
+		for (pos = 0, cg = desc; cg; cg = cgroup_parent(cg)) {
+			if (pos && !(cg->bpf.flags[atype] & BPF_F_ALLOW_MULTI))
+				continue;
+
+			head = &cg->bpf.progs[atype];
+			hlist_for_each_entry(pl, head, node) {
+				if (!prog_list_prog(pl))
+					continue;
+				if (pl->prog == prog && pl->link == link)
+					goto found;
+				pos++;
+			}
+		}
+
+		/* no link or prog match, skip the cgroup of this layer */
+		continue;
+found:
+		progs = rcu_dereference_protected(
+				desc->bpf.effective[atype],
+				lockdep_is_held(&cgroup_mutex));
+
+		/* Remove the program from the array */
+		WARN_ONCE(bpf_prog_array_delete_safe_at(progs, pos),
+			  "Failed to purge a prog from array at index %d", pos);
+	}
+}
+
+/**
+ * __cgroup_bpf_detach() - Detach the program or link from a cgroup, and
+ *                         propagate the change to descendants
+ * @cgrp: The cgroup which descendants to traverse
+ * @prog: A program to detach or NULL
+ * @link: A link to detach or NULL
+ * @type: Type of detach operation
+ *
+ * At most one of @prog or @link can be non-NULL.
+ * Must be called with cgroup_mutex held.
+ */
+static int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
+			       struct bpf_cgroup_link *link, enum bpf_attach_type type)
+{
+	enum cgroup_bpf_attach_type atype;
+	struct bpf_prog *old_prog;
+	struct bpf_prog_list *pl;
+	struct hlist_head *progs;
+	u32 attach_btf_id = 0;
+	u32 flags;
+
+	if (prog)
+		attach_btf_id = prog->aux->attach_btf_id;
+	if (link)
+		attach_btf_id = link->link.prog->aux->attach_btf_id;
+
+	atype = bpf_cgroup_atype_find(type, attach_btf_id);
+	if (atype < 0)
+		return -EINVAL;
+
+	progs = &cgrp->bpf.progs[atype];
+	flags = cgrp->bpf.flags[atype];
+
+	if (prog && link)
+		/* only one of prog or link can be specified */
+		return -EINVAL;
+
+	pl = find_detach_entry(progs, prog, link, flags & BPF_F_ALLOW_MULTI);
+	if (IS_ERR(pl))
+		return PTR_ERR(pl);
+
+	/* mark it deleted, so it's ignored while recomputing effective */
+	old_prog = pl->prog;
+	pl->prog = NULL;
+	pl->link = NULL;
+
+	if (update_effective_progs(cgrp, atype)) {
+		/* if update effective array failed replace the prog with a dummy prog*/
+		pl->prog = old_prog;
+		pl->link = link;
+		purge_effective_progs(cgrp, old_prog, link, atype);
+	}
+
+	/* now can actually delete it from this cgroup list */
+	hlist_del(&pl->node);
+
+	kfree(pl);
+	if (hlist_empty(progs))
+		/* last program was detached, reset flags to zero */
+		cgrp->bpf.flags[atype] = 0;
+	if (old_prog) {
+		if (type == BPF_LSM_CGROUP)
+			bpf_trampoline_unlink_cgroup_shim(old_prog);
+		bpf_prog_put(old_prog);
+	}
+	static_branch_dec(&cgroup_bpf_enabled_key[atype]);
+	return 0;
+}
+
+static int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
+			     enum bpf_attach_type type)
+{
+	int ret;
+
+	cgroup_lock();
+	ret = __cgroup_bpf_detach(cgrp, prog, NULL, type);
+	cgroup_unlock();
+	return ret;
+}
+
+/* Must be called with cgroup_mutex held to avoid races. */
+static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
+			      union bpf_attr __user *uattr)
+{
+	__u32 __user *prog_attach_flags = u64_to_user_ptr(attr->query.prog_attach_flags);
+	bool effective_query = attr->query.query_flags & BPF_F_QUERY_EFFECTIVE;
+	__u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
+	enum bpf_attach_type type = attr->query.attach_type;
+	enum cgroup_bpf_attach_type from_atype, to_atype;
+	enum cgroup_bpf_attach_type atype;
+	struct bpf_prog_array *effective;
+	int cnt, ret = 0, i;
+	int total_cnt = 0;
+	u32 flags;
+
+	if (effective_query && prog_attach_flags)
+		return -EINVAL;
+
+	if (type == BPF_LSM_CGROUP) {
+		if (!effective_query && attr->query.prog_cnt &&
+		    prog_ids && !prog_attach_flags)
+			return -EINVAL;
+
+		from_atype = CGROUP_LSM_START;
+		to_atype = CGROUP_LSM_END;
+		flags = 0;
+	} else {
+		from_atype = to_cgroup_bpf_attach_type(type);
+		if (from_atype < 0)
+			return -EINVAL;
+		to_atype = from_atype;
+		flags = cgrp->bpf.flags[from_atype];
+	}
+
+	for (atype = from_atype; atype <= to_atype; atype++) {
+		if (effective_query) {
+			effective = rcu_dereference_protected(cgrp->bpf.effective[atype],
+							      lockdep_is_held(&cgroup_mutex));
+			total_cnt += bpf_prog_array_length(effective);
+		} else {
+			total_cnt += prog_list_length(&cgrp->bpf.progs[atype]);
+		}
+	}
+
+	/* always output uattr->query.attach_flags as 0 during effective query */
+	flags = effective_query ? 0 : flags;
+	if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
+		return -EFAULT;
+	if (copy_to_user(&uattr->query.prog_cnt, &total_cnt, sizeof(total_cnt)))
+		return -EFAULT;
+	if (attr->query.prog_cnt == 0 || !prog_ids || !total_cnt)
+		/* return early if user requested only program count + flags */
+		return 0;
+
+	if (attr->query.prog_cnt < total_cnt) {
+		total_cnt = attr->query.prog_cnt;
+		ret = -ENOSPC;
+	}
+
+	for (atype = from_atype; atype <= to_atype && total_cnt; atype++) {
+		if (effective_query) {
+			effective = rcu_dereference_protected(cgrp->bpf.effective[atype],
+							      lockdep_is_held(&cgroup_mutex));
+			cnt = min_t(int, bpf_prog_array_length(effective), total_cnt);
+			ret = bpf_prog_array_copy_to_user(effective, prog_ids, cnt);
+		} else {
+			struct hlist_head *progs;
+			struct bpf_prog_list *pl;
+			struct bpf_prog *prog;
+			u32 id;
+
+			progs = &cgrp->bpf.progs[atype];
+			cnt = min_t(int, prog_list_length(progs), total_cnt);
+			i = 0;
+			hlist_for_each_entry(pl, progs, node) {
+				prog = prog_list_prog(pl);
+				id = prog->aux->id;
+				if (copy_to_user(prog_ids + i, &id, sizeof(id)))
+					return -EFAULT;
+				if (++i == cnt)
+					break;
+			}
+
+			if (prog_attach_flags) {
+				flags = cgrp->bpf.flags[atype];
+
+				for (i = 0; i < cnt; i++)
+					if (copy_to_user(prog_attach_flags + i,
+							 &flags, sizeof(flags)))
+						return -EFAULT;
+				prog_attach_flags += cnt;
+			}
+		}
+
+		prog_ids += cnt;
+		total_cnt -= cnt;
+	}
+	return ret;
+}
+
+static int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
+			    union bpf_attr __user *uattr)
+{
+	int ret;
+
+	cgroup_lock();
+	ret = __cgroup_bpf_query(cgrp, attr, uattr);
+	cgroup_unlock();
+	return ret;
+}
+
+int cgroup_bpf_prog_attach(const union bpf_attr *attr,
+			   enum bpf_prog_type ptype, struct bpf_prog *prog)
+{
+	struct bpf_prog *replace_prog = NULL;
+	struct cgroup *cgrp;
+	int ret;
+
+	cgrp = cgroup_get_from_fd(attr->target_fd);
+	if (IS_ERR(cgrp))
+		return PTR_ERR(cgrp);
+
+	if ((attr->attach_flags & BPF_F_ALLOW_MULTI) &&
+	    (attr->attach_flags & BPF_F_REPLACE)) {
+		replace_prog = bpf_prog_get_type(attr->replace_bpf_fd, ptype);
+		if (IS_ERR(replace_prog)) {
+			cgroup_put(cgrp);
+			return PTR_ERR(replace_prog);
+		}
+	}
+
+	ret = cgroup_bpf_attach(cgrp, prog, replace_prog, NULL,
+				attr->attach_type, attr->attach_flags);
+
+	if (replace_prog)
+		bpf_prog_put(replace_prog);
+	cgroup_put(cgrp);
+	return ret;
+}
+
+int cgroup_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype)
+{
+	struct bpf_prog *prog;
+	struct cgroup *cgrp;
+	int ret;
+
+	cgrp = cgroup_get_from_fd(attr->target_fd);
+	if (IS_ERR(cgrp))
+		return PTR_ERR(cgrp);
+
+	prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
+	if (IS_ERR(prog))
+		prog = NULL;
+
+	ret = cgroup_bpf_detach(cgrp, prog, attr->attach_type);
+	if (prog)
+		bpf_prog_put(prog);
+
+	cgroup_put(cgrp);
+	return ret;
+}
+
+static void bpf_cgroup_link_release(struct bpf_link *link)
+{
+	struct bpf_cgroup_link *cg_link =
+		container_of(link, struct bpf_cgroup_link, link);
+	struct cgroup *cg;
+
+	/* link might have been auto-detached by dying cgroup already,
+	 * in that case our work is done here
+	 */
+	if (!cg_link->cgroup)
+		return;
+
+	cgroup_lock();
+
+	/* re-check cgroup under lock again */
+	if (!cg_link->cgroup) {
+		cgroup_unlock();
+		return;
+	}
+
+	WARN_ON(__cgroup_bpf_detach(cg_link->cgroup, NULL, cg_link,
+				    cg_link->type));
+	if (cg_link->type == BPF_LSM_CGROUP)
+		bpf_trampoline_unlink_cgroup_shim(cg_link->link.prog);
+
+	cg = cg_link->cgroup;
+	cg_link->cgroup = NULL;
+
+	cgroup_unlock();
+
+	cgroup_put(cg);
+}
+
+static void bpf_cgroup_link_dealloc(struct bpf_link *link)
+{
+	struct bpf_cgroup_link *cg_link =
+		container_of(link, struct bpf_cgroup_link, link);
+
+	kfree(cg_link);
+}
+
+static int bpf_cgroup_link_detach(struct bpf_link *link)
+{
+	bpf_cgroup_link_release(link);
+
+	return 0;
+}
+
+static void bpf_cgroup_link_show_fdinfo(const struct bpf_link *link,
+					struct seq_file *seq)
+{
+	struct bpf_cgroup_link *cg_link =
+		container_of(link, struct bpf_cgroup_link, link);
+	u64 cg_id = 0;
+
+	cgroup_lock();
+	if (cg_link->cgroup)
+		cg_id = cgroup_id(cg_link->cgroup);
+	cgroup_unlock();
+
+	seq_printf(seq,
+		   "cgroup_id:\t%llu\n"
+		   "attach_type:\t%d\n",
+		   cg_id,
+		   cg_link->type);
+}
+
+static int bpf_cgroup_link_fill_link_info(const struct bpf_link *link,
+					  struct bpf_link_info *info)
+{
+	struct bpf_cgroup_link *cg_link =
+		container_of(link, struct bpf_cgroup_link, link);
+	u64 cg_id = 0;
+
+	cgroup_lock();
+	if (cg_link->cgroup)
+		cg_id = cgroup_id(cg_link->cgroup);
+	cgroup_unlock();
+
+	info->cgroup.cgroup_id = cg_id;
+	info->cgroup.attach_type = cg_link->type;
+	return 0;
+}
+
+static const struct bpf_link_ops bpf_cgroup_link_lops = {
+	.release = bpf_cgroup_link_release,
+	.dealloc = bpf_cgroup_link_dealloc,
+	.detach = bpf_cgroup_link_detach,
+	.update_prog = cgroup_bpf_replace,
+	.show_fdinfo = bpf_cgroup_link_show_fdinfo,
+	.fill_link_info = bpf_cgroup_link_fill_link_info,
+};
+
+int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
+{
+	struct bpf_link_primer link_primer;
+	struct bpf_cgroup_link *link;
+	struct cgroup *cgrp;
+	int err;
+
+	if (attr->link_create.flags)
+		return -EINVAL;
+
+	cgrp = cgroup_get_from_fd(attr->link_create.target_fd);
+	if (IS_ERR(cgrp))
+		return PTR_ERR(cgrp);
+
+	link = kzalloc(sizeof(*link), GFP_USER);
+	if (!link) {
+		err = -ENOMEM;
+		goto out_put_cgroup;
+	}
+	bpf_link_init(&link->link, BPF_LINK_TYPE_CGROUP, &bpf_cgroup_link_lops,
+		      prog);
+	link->cgroup = cgrp;
+	link->type = attr->link_create.attach_type;
+
+	err = bpf_link_prime(&link->link, &link_primer);
+	if (err) {
+		kfree(link);
+		goto out_put_cgroup;
+	}
+
+	err = cgroup_bpf_attach(cgrp, NULL, NULL, link,
+				link->type, BPF_F_ALLOW_MULTI);
+	if (err) {
+		bpf_link_cleanup(&link_primer);
+		goto out_put_cgroup;
+	}
+
+	return bpf_link_settle(&link_primer);
+
+out_put_cgroup:
+	cgroup_put(cgrp);
+	return err;
+}
+
+int cgroup_bpf_prog_query(const union bpf_attr *attr,
+			  union bpf_attr __user *uattr)
+{
+	struct cgroup *cgrp;
+	int ret;
+
+	cgrp = cgroup_get_from_fd(attr->query.target_fd);
+	if (IS_ERR(cgrp))
+		return PTR_ERR(cgrp);
+
+	ret = cgroup_bpf_query(cgrp, attr, uattr);
+
+	cgroup_put(cgrp);
+	return ret;
+}
+
+/**
+ * __cgroup_bpf_run_filter_skb() - Run a program for packet filtering
+ * @sk: The socket sending or receiving traffic
+ * @skb: The skb that is being sent or received
+ * @type: The type of program to be executed
+ *
+ * If no socket is passed, or the socket is not of type INET or INET6,
+ * this function does nothing and returns 0.
+ *
+ * The program type passed in via @type must be suitable for network
+ * filtering. No further check is performed to assert that.
+ *
+ * For egress packets, this function can return:
+ *   NET_XMIT_SUCCESS    (0)	- continue with packet output
+ *   NET_XMIT_DROP       (1)	- drop packet and notify TCP to call cwr
+ *   NET_XMIT_CN         (2)	- continue with packet output and notify TCP
+ *				  to call cwr
+ *   -err			- drop packet
+ *
+ * For ingress packets, this function will return -EPERM if any
+ * attached program was found and if it returned != 1 during execution.
+ * Otherwise 0 is returned.
+ */
+int __cgroup_bpf_run_filter_skb(struct sock *sk,
+				struct sk_buff *skb,
+				enum cgroup_bpf_attach_type atype)
+{
+	unsigned int offset = skb->data - skb_network_header(skb);
+	struct sock *save_sk;
+	void *saved_data_end;
+	struct cgroup *cgrp;
+	int ret;
+
+	if (!sk || !sk_fullsock(sk))
+		return 0;
+
+	if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)
+		return 0;
+
+	cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	save_sk = skb->sk;
+	skb->sk = sk;
+	__skb_push(skb, offset);
+
+	/* compute pointers for the bpf prog */
+	bpf_compute_and_save_data_end(skb, &saved_data_end);
+
+	if (atype == CGROUP_INET_EGRESS) {
+		u32 flags = 0;
+		bool cn;
+
+		ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, skb,
+					    __bpf_prog_run_save_cb, 0, &flags);
+
+		/* Return values of CGROUP EGRESS BPF programs are:
+		 *   0: drop packet
+		 *   1: keep packet
+		 *   2: drop packet and cn
+		 *   3: keep packet and cn
+		 *
+		 * The returned value is then converted to one of the NET_XMIT
+		 * or an error code that is then interpreted as drop packet
+		 * (and no cn):
+		 *   0: NET_XMIT_SUCCESS  skb should be transmitted
+		 *   1: NET_XMIT_DROP     skb should be dropped and cn
+		 *   2: NET_XMIT_CN       skb should be transmitted and cn
+		 *   3: -err              skb should be dropped
+		 */
+
+		cn = flags & BPF_RET_SET_CN;
+		if (ret && !IS_ERR_VALUE((long)ret))
+			ret = -EFAULT;
+		if (!ret)
+			ret = (cn ? NET_XMIT_CN : NET_XMIT_SUCCESS);
+		else
+			ret = (cn ? NET_XMIT_DROP : ret);
+	} else {
+		ret = bpf_prog_run_array_cg(&cgrp->bpf, atype,
+					    skb, __bpf_prog_run_save_cb, 0,
+					    NULL);
+		if (ret && !IS_ERR_VALUE((long)ret))
+			ret = -EFAULT;
+	}
+	bpf_restore_data_end(skb, saved_data_end);
+	__skb_pull(skb, offset);
+	skb->sk = save_sk;
+
+	return ret;
+}
+EXPORT_SYMBOL(__cgroup_bpf_run_filter_skb);
+
+/**
+ * __cgroup_bpf_run_filter_sk() - Run a program on a sock
+ * @sk: sock structure to manipulate
+ * @type: The type of program to be executed
+ *
+ * socket is passed is expected to be of type INET or INET6.
+ *
+ * The program type passed in via @type must be suitable for sock
+ * filtering. No further check is performed to assert that.
+ *
+ * This function will return %-EPERM if any if an attached program was found
+ * and if it returned != 1 during execution. In all other cases, 0 is returned.
+ */
+int __cgroup_bpf_run_filter_sk(struct sock *sk,
+			       enum cgroup_bpf_attach_type atype)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+
+	return bpf_prog_run_array_cg(&cgrp->bpf, atype, sk, bpf_prog_run, 0,
+				     NULL);
+}
+EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk);
+
+/**
+ * __cgroup_bpf_run_filter_sock_addr() - Run a program on a sock and
+ *                                       provided by user sockaddr
+ * @sk: sock struct that will use sockaddr
+ * @uaddr: sockaddr struct provided by user
+ * @type: The type of program to be executed
+ * @t_ctx: Pointer to attach type specific context
+ * @flags: Pointer to u32 which contains higher bits of BPF program
+ *         return value (OR'ed together).
+ *
+ * socket is expected to be of type INET or INET6.
+ *
+ * This function will return %-EPERM if an attached program is found and
+ * returned value != 1 during execution. In all other cases, 0 is returned.
+ */
+int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
+				      struct sockaddr *uaddr,
+				      enum cgroup_bpf_attach_type atype,
+				      void *t_ctx,
+				      u32 *flags)
+{
+	struct bpf_sock_addr_kern ctx = {
+		.sk = sk,
+		.uaddr = uaddr,
+		.t_ctx = t_ctx,
+	};
+	struct sockaddr_storage unspec;
+	struct cgroup *cgrp;
+
+	/* Check socket family since not all sockets represent network
+	 * endpoint (e.g. AF_UNIX).
+	 */
+	if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)
+		return 0;
+
+	if (!ctx.uaddr) {
+		memset(&unspec, 0, sizeof(unspec));
+		ctx.uaddr = (struct sockaddr *)&unspec;
+	}
+
+	cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	return bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run,
+				     0, flags);
+}
+EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_addr);
+
+/**
+ * __cgroup_bpf_run_filter_sock_ops() - Run a program on a sock
+ * @sk: socket to get cgroup from
+ * @sock_ops: bpf_sock_ops_kern struct to pass to program. Contains
+ * sk with connection information (IP addresses, etc.) May not contain
+ * cgroup info if it is a req sock.
+ * @type: The type of program to be executed
+ *
+ * socket passed is expected to be of type INET or INET6.
+ *
+ * The program type passed in via @type must be suitable for sock_ops
+ * filtering. No further check is performed to assert that.
+ *
+ * This function will return %-EPERM if any if an attached program was found
+ * and if it returned != 1 during execution. In all other cases, 0 is returned.
+ */
+int __cgroup_bpf_run_filter_sock_ops(struct sock *sk,
+				     struct bpf_sock_ops_kern *sock_ops,
+				     enum cgroup_bpf_attach_type atype)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+
+	return bpf_prog_run_array_cg(&cgrp->bpf, atype, sock_ops, bpf_prog_run,
+				     0, NULL);
+}
+EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_ops);
+
+int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
+				      short access, enum cgroup_bpf_attach_type atype)
+{
+	struct cgroup *cgrp;
+	struct bpf_cgroup_dev_ctx ctx = {
+		.access_type = (access << 16) | dev_type,
+		.major = major,
+		.minor = minor,
+	};
+	int ret;
+
+	rcu_read_lock();
+	cgrp = task_dfl_cgroup(current);
+	ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0,
+				    NULL);
+	rcu_read_unlock();
+
+	return ret;
+}
+
+BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags)
+{
+	/* flags argument is not used now,
+	 * but provides an ability to extend the API.
+	 * verifier checks that its value is correct.
+	 */
+	enum bpf_cgroup_storage_type stype = cgroup_storage_type(map);
+	struct bpf_cgroup_storage *storage;
+	struct bpf_cg_run_ctx *ctx;
+	void *ptr;
+
+	/* get current cgroup storage from BPF run context */
+	ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
+	storage = ctx->prog_item->cgroup_storage[stype];
+
+	if (stype == BPF_CGROUP_STORAGE_SHARED)
+		ptr = &READ_ONCE(storage->buf)->data[0];
+	else
+		ptr = this_cpu_ptr(storage->percpu_buf);
+
+	return (unsigned long)ptr;
+}
+
+const struct bpf_func_proto bpf_get_local_storage_proto = {
+	.func		= bpf_get_local_storage,
+	.gpl_only	= false,
+	.ret_type	= RET_PTR_TO_MAP_VALUE,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_0(bpf_get_retval)
+{
+	struct bpf_cg_run_ctx *ctx =
+		container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
+
+	return ctx->retval;
+}
+
+const struct bpf_func_proto bpf_get_retval_proto = {
+	.func		= bpf_get_retval,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_1(bpf_set_retval, int, retval)
+{
+	struct bpf_cg_run_ctx *ctx =
+		container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
+
+	ctx->retval = retval;
+	return 0;
+}
+
+const struct bpf_func_proto bpf_set_retval_proto = {
+	.func		= bpf_set_retval,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_ANYTHING,
+};
+
+static const struct bpf_func_proto *
+cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	const struct bpf_func_proto *func_proto;
+
+	func_proto = cgroup_common_func_proto(func_id, prog);
+	if (func_proto)
+		return func_proto;
+
+	func_proto = cgroup_current_func_proto(func_id, prog);
+	if (func_proto)
+		return func_proto;
+
+	switch (func_id) {
+	case BPF_FUNC_perf_event_output:
+		return &bpf_event_output_data_proto;
+	default:
+		return bpf_base_func_proto(func_id);
+	}
+}
+
+static bool cgroup_dev_is_valid_access(int off, int size,
+				       enum bpf_access_type type,
+				       const struct bpf_prog *prog,
+				       struct bpf_insn_access_aux *info)
+{
+	const int size_default = sizeof(__u32);
+
+	if (type == BPF_WRITE)
+		return false;
+
+	if (off < 0 || off + size > sizeof(struct bpf_cgroup_dev_ctx))
+		return false;
+	/* The verifier guarantees that size > 0. */
+	if (off % size != 0)
+		return false;
+
+	switch (off) {
+	case bpf_ctx_range(struct bpf_cgroup_dev_ctx, access_type):
+		bpf_ctx_record_field_size(info, size_default);
+		if (!bpf_ctx_narrow_access_ok(off, size, size_default))
+			return false;
+		break;
+	default:
+		if (size != size_default)
+			return false;
+	}
+
+	return true;
+}
+
+const struct bpf_prog_ops cg_dev_prog_ops = {
+};
+
+const struct bpf_verifier_ops cg_dev_verifier_ops = {
+	.get_func_proto		= cgroup_dev_func_proto,
+	.is_valid_access	= cgroup_dev_is_valid_access,
+};
+
+/**
+ * __cgroup_bpf_run_filter_sysctl - Run a program on sysctl
+ *
+ * @head: sysctl table header
+ * @table: sysctl table
+ * @write: sysctl is being read (= 0) or written (= 1)
+ * @buf: pointer to buffer (in and out)
+ * @pcount: value-result argument: value is size of buffer pointed to by @buf,
+ *	result is size of @new_buf if program set new value, initial value
+ *	otherwise
+ * @ppos: value-result argument: value is position at which read from or write
+ *	to sysctl is happening, result is new position if program overrode it,
+ *	initial value otherwise
+ * @type: type of program to be executed
+ *
+ * Program is run when sysctl is being accessed, either read or written, and
+ * can allow or deny such access.
+ *
+ * This function will return %-EPERM if an attached program is found and
+ * returned value != 1 during execution. In all other cases 0 is returned.
+ */
+int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,
+				   struct ctl_table *table, int write,
+				   char **buf, size_t *pcount, loff_t *ppos,
+				   enum cgroup_bpf_attach_type atype)
+{
+	struct bpf_sysctl_kern ctx = {
+		.head = head,
+		.table = table,
+		.write = write,
+		.ppos = ppos,
+		.cur_val = NULL,
+		.cur_len = PAGE_SIZE,
+		.new_val = NULL,
+		.new_len = 0,
+		.new_updated = 0,
+	};
+	struct cgroup *cgrp;
+	loff_t pos = 0;
+	int ret;
+
+	ctx.cur_val = kmalloc_track_caller(ctx.cur_len, GFP_KERNEL);
+	if (!ctx.cur_val ||
+	    table->proc_handler(table, 0, ctx.cur_val, &ctx.cur_len, &pos)) {
+		/* Let BPF program decide how to proceed. */
+		ctx.cur_len = 0;
+	}
+
+	if (write && *buf && *pcount) {
+		/* BPF program should be able to override new value with a
+		 * buffer bigger than provided by user.
+		 */
+		ctx.new_val = kmalloc_track_caller(PAGE_SIZE, GFP_KERNEL);
+		ctx.new_len = min_t(size_t, PAGE_SIZE, *pcount);
+		if (ctx.new_val) {
+			memcpy(ctx.new_val, *buf, ctx.new_len);
+		} else {
+			/* Let BPF program decide how to proceed. */
+			ctx.new_len = 0;
+		}
+	}
+
+	rcu_read_lock();
+	cgrp = task_dfl_cgroup(current);
+	ret = bpf_prog_run_array_cg(&cgrp->bpf, atype, &ctx, bpf_prog_run, 0,
+				    NULL);
+	rcu_read_unlock();
+
+	kfree(ctx.cur_val);
+
+	if (ret == 1 && ctx.new_updated) {
+		kfree(*buf);
+		*buf = ctx.new_val;
+		*pcount = ctx.new_len;
+	} else {
+		kfree(ctx.new_val);
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_NET
+static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen,
+			     struct bpf_sockopt_buf *buf)
+{
+	if (unlikely(max_optlen < 0))
+		return -EINVAL;
+
+	if (unlikely(max_optlen > PAGE_SIZE)) {
+		/* We don't expose optvals that are greater than PAGE_SIZE
+		 * to the BPF program.
+		 */
+		max_optlen = PAGE_SIZE;
+	}
+
+	if (max_optlen <= sizeof(buf->data)) {
+		/* When the optval fits into BPF_SOCKOPT_KERN_BUF_SIZE
+		 * bytes avoid the cost of kzalloc.
+		 */
+		ctx->optval = buf->data;
+		ctx->optval_end = ctx->optval + max_optlen;
+		return max_optlen;
+	}
+
+	ctx->optval = kzalloc(max_optlen, GFP_USER);
+	if (!ctx->optval)
+		return -ENOMEM;
+
+	ctx->optval_end = ctx->optval + max_optlen;
+
+	return max_optlen;
+}
+
+static void sockopt_free_buf(struct bpf_sockopt_kern *ctx,
+			     struct bpf_sockopt_buf *buf)
+{
+	if (ctx->optval == buf->data)
+		return;
+	kfree(ctx->optval);
+}
+
+static bool sockopt_buf_allocated(struct bpf_sockopt_kern *ctx,
+				  struct bpf_sockopt_buf *buf)
+{
+	return ctx->optval != buf->data;
+}
+
+int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
+				       int *optname, char __user *optval,
+				       int *optlen, char **kernel_optval)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	struct bpf_sockopt_buf buf = {};
+	struct bpf_sockopt_kern ctx = {
+		.sk = sk,
+		.level = *level,
+		.optname = *optname,
+	};
+	int ret, max_optlen;
+
+	/* Allocate a bit more than the initial user buffer for
+	 * BPF program. The canonical use case is overriding
+	 * TCP_CONGESTION(nv) to TCP_CONGESTION(cubic).
+	 */
+	max_optlen = max_t(int, 16, *optlen);
+	max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf);
+	if (max_optlen < 0)
+		return max_optlen;
+
+	ctx.optlen = *optlen;
+
+	if (copy_from_user(ctx.optval, optval, min(*optlen, max_optlen)) != 0) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	lock_sock(sk);
+	ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_SETSOCKOPT,
+				    &ctx, bpf_prog_run, 0, NULL);
+	release_sock(sk);
+
+	if (ret)
+		goto out;
+
+	if (ctx.optlen == -1) {
+		/* optlen set to -1, bypass kernel */
+		ret = 1;
+	} else if (ctx.optlen > max_optlen || ctx.optlen < -1) {
+		/* optlen is out of bounds */
+		if (*optlen > PAGE_SIZE && ctx.optlen >= 0) {
+			pr_info_once("bpf setsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n",
+				     ctx.optlen, max_optlen);
+			ret = 0;
+			goto out;
+		}
+		ret = -EFAULT;
+	} else {
+		/* optlen within bounds, run kernel handler */
+		ret = 0;
+
+		/* export any potential modifications */
+		*level = ctx.level;
+		*optname = ctx.optname;
+
+		/* optlen == 0 from BPF indicates that we should
+		 * use original userspace data.
+		 */
+		if (ctx.optlen != 0) {
+			*optlen = ctx.optlen;
+			/* We've used bpf_sockopt_kern->buf as an intermediary
+			 * storage, but the BPF program indicates that we need
+			 * to pass this data to the kernel setsockopt handler.
+			 * No way to export on-stack buf, have to allocate a
+			 * new buffer.
+			 */
+			if (!sockopt_buf_allocated(&ctx, &buf)) {
+				void *p = kmalloc(ctx.optlen, GFP_USER);
+
+				if (!p) {
+					ret = -ENOMEM;
+					goto out;
+				}
+				memcpy(p, ctx.optval, ctx.optlen);
+				*kernel_optval = p;
+			} else {
+				*kernel_optval = ctx.optval;
+			}
+			/* export and don't free sockopt buf */
+			return 0;
+		}
+	}
+
+out:
+	sockopt_free_buf(&ctx, &buf);
+	return ret;
+}
+
+int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
+				       int optname, char __user *optval,
+				       int __user *optlen, int max_optlen,
+				       int retval)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	struct bpf_sockopt_buf buf = {};
+	struct bpf_sockopt_kern ctx = {
+		.sk = sk,
+		.level = level,
+		.optname = optname,
+		.current_task = current,
+	};
+	int orig_optlen;
+	int ret;
+
+	orig_optlen = max_optlen;
+	ctx.optlen = max_optlen;
+	max_optlen = sockopt_alloc_buf(&ctx, max_optlen, &buf);
+	if (max_optlen < 0)
+		return max_optlen;
+
+	if (!retval) {
+		/* If kernel getsockopt finished successfully,
+		 * copy whatever was returned to the user back
+		 * into our temporary buffer. Set optlen to the
+		 * one that kernel returned as well to let
+		 * BPF programs inspect the value.
+		 */
+
+		if (get_user(ctx.optlen, optlen)) {
+			ret = -EFAULT;
+			goto out;
+		}
+
+		if (ctx.optlen < 0) {
+			ret = -EFAULT;
+			goto out;
+		}
+		orig_optlen = ctx.optlen;
+
+		if (copy_from_user(ctx.optval, optval,
+				   min(ctx.optlen, max_optlen)) != 0) {
+			ret = -EFAULT;
+			goto out;
+		}
+	}
+
+	lock_sock(sk);
+	ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT,
+				    &ctx, bpf_prog_run, retval, NULL);
+	release_sock(sk);
+
+	if (ret < 0)
+		goto out;
+
+	if (optval && (ctx.optlen > max_optlen || ctx.optlen < 0)) {
+		if (orig_optlen > PAGE_SIZE && ctx.optlen >= 0) {
+			pr_info_once("bpf getsockopt: ignoring program buffer with optlen=%d (max_optlen=%d)\n",
+				     ctx.optlen, max_optlen);
+			ret = retval;
+			goto out;
+		}
+		ret = -EFAULT;
+		goto out;
+	}
+
+	if (ctx.optlen != 0) {
+		if (optval && copy_to_user(optval, ctx.optval, ctx.optlen)) {
+			ret = -EFAULT;
+			goto out;
+		}
+		if (put_user(ctx.optlen, optlen)) {
+			ret = -EFAULT;
+			goto out;
+		}
+	}
+
+out:
+	sockopt_free_buf(&ctx, &buf);
+	return ret;
+}
+
+int __cgroup_bpf_run_filter_getsockopt_kern(struct sock *sk, int level,
+					    int optname, void *optval,
+					    int *optlen, int retval)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
+	struct bpf_sockopt_kern ctx = {
+		.sk = sk,
+		.level = level,
+		.optname = optname,
+		.optlen = *optlen,
+		.optval = optval,
+		.optval_end = optval + *optlen,
+		.current_task = current,
+	};
+	int ret;
+
+	/* Note that __cgroup_bpf_run_filter_getsockopt doesn't copy
+	 * user data back into BPF buffer when reval != 0. This is
+	 * done as an optimization to avoid extra copy, assuming
+	 * kernel won't populate the data in case of an error.
+	 * Here we always pass the data and memset() should
+	 * be called if that data shouldn't be "exported".
+	 */
+
+	ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT,
+				    &ctx, bpf_prog_run, retval, NULL);
+	if (ret < 0)
+		return ret;
+
+	if (ctx.optlen > *optlen)
+		return -EFAULT;
+
+	/* BPF programs can shrink the buffer, export the modifications.
+	 */
+	if (ctx.optlen != 0)
+		*optlen = ctx.optlen;
+
+	return ret;
+}
+#endif
+
+static ssize_t sysctl_cpy_dir(const struct ctl_dir *dir, char **bufp,
+			      size_t *lenp)
+{
+	ssize_t tmp_ret = 0, ret;
+
+	if (dir->header.parent) {
+		tmp_ret = sysctl_cpy_dir(dir->header.parent, bufp, lenp);
+		if (tmp_ret < 0)
+			return tmp_ret;
+	}
+
+	ret = strscpy(*bufp, dir->header.ctl_table[0].procname, *lenp);
+	if (ret < 0)
+		return ret;
+	*bufp += ret;
+	*lenp -= ret;
+	ret += tmp_ret;
+
+	/* Avoid leading slash. */
+	if (!ret)
+		return ret;
+
+	tmp_ret = strscpy(*bufp, "/", *lenp);
+	if (tmp_ret < 0)
+		return tmp_ret;
+	*bufp += tmp_ret;
+	*lenp -= tmp_ret;
+
+	return ret + tmp_ret;
+}
+
+BPF_CALL_4(bpf_sysctl_get_name, struct bpf_sysctl_kern *, ctx, char *, buf,
+	   size_t, buf_len, u64, flags)
+{
+	ssize_t tmp_ret = 0, ret;
+
+	if (!buf)
+		return -EINVAL;
+
+	if (!(flags & BPF_F_SYSCTL_BASE_NAME)) {
+		if (!ctx->head)
+			return -EINVAL;
+		tmp_ret = sysctl_cpy_dir(ctx->head->parent, &buf, &buf_len);
+		if (tmp_ret < 0)
+			return tmp_ret;
+	}
+
+	ret = strscpy(buf, ctx->table->procname, buf_len);
+
+	return ret < 0 ? ret : tmp_ret + ret;
+}
+
+static const struct bpf_func_proto bpf_sysctl_get_name_proto = {
+	.func		= bpf_sysctl_get_name,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_MEM,
+	.arg3_type	= ARG_CONST_SIZE,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+static int copy_sysctl_value(char *dst, size_t dst_len, char *src,
+			     size_t src_len)
+{
+	if (!dst)
+		return -EINVAL;
+
+	if (!dst_len)
+		return -E2BIG;
+
+	if (!src || !src_len) {
+		memset(dst, 0, dst_len);
+		return -EINVAL;
+	}
+
+	memcpy(dst, src, min(dst_len, src_len));
+
+	if (dst_len > src_len) {
+		memset(dst + src_len, '\0', dst_len - src_len);
+		return src_len;
+	}
+
+	dst[dst_len - 1] = '\0';
+
+	return -E2BIG;
+}
+
+BPF_CALL_3(bpf_sysctl_get_current_value, struct bpf_sysctl_kern *, ctx,
+	   char *, buf, size_t, buf_len)
+{
+	return copy_sysctl_value(buf, buf_len, ctx->cur_val, ctx->cur_len);
+}
+
+static const struct bpf_func_proto bpf_sysctl_get_current_value_proto = {
+	.func		= bpf_sysctl_get_current_value,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg3_type	= ARG_CONST_SIZE,
+};
+
+BPF_CALL_3(bpf_sysctl_get_new_value, struct bpf_sysctl_kern *, ctx, char *, buf,
+	   size_t, buf_len)
+{
+	if (!ctx->write) {
+		if (buf && buf_len)
+			memset(buf, '\0', buf_len);
+		return -EINVAL;
+	}
+	return copy_sysctl_value(buf, buf_len, ctx->new_val, ctx->new_len);
+}
+
+static const struct bpf_func_proto bpf_sysctl_get_new_value_proto = {
+	.func		= bpf_sysctl_get_new_value,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg3_type	= ARG_CONST_SIZE,
+};
+
+BPF_CALL_3(bpf_sysctl_set_new_value, struct bpf_sysctl_kern *, ctx,
+	   const char *, buf, size_t, buf_len)
+{
+	if (!ctx->write || !ctx->new_val || !ctx->new_len || !buf || !buf_len)
+		return -EINVAL;
+
+	if (buf_len > PAGE_SIZE - 1)
+		return -E2BIG;
+
+	memcpy(ctx->new_val, buf, buf_len);
+	ctx->new_len = buf_len;
+	ctx->new_updated = 1;
+
+	return 0;
+}
+
+static const struct bpf_func_proto bpf_sysctl_set_new_value_proto = {
+	.func		= bpf_sysctl_set_new_value,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg3_type	= ARG_CONST_SIZE,
+};
+
+static const struct bpf_func_proto *
+sysctl_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	const struct bpf_func_proto *func_proto;
+
+	func_proto = cgroup_common_func_proto(func_id, prog);
+	if (func_proto)
+		return func_proto;
+
+	func_proto = cgroup_current_func_proto(func_id, prog);
+	if (func_proto)
+		return func_proto;
+
+	switch (func_id) {
+	case BPF_FUNC_sysctl_get_name:
+		return &bpf_sysctl_get_name_proto;
+	case BPF_FUNC_sysctl_get_current_value:
+		return &bpf_sysctl_get_current_value_proto;
+	case BPF_FUNC_sysctl_get_new_value:
+		return &bpf_sysctl_get_new_value_proto;
+	case BPF_FUNC_sysctl_set_new_value:
+		return &bpf_sysctl_set_new_value_proto;
+	case BPF_FUNC_ktime_get_coarse_ns:
+		return &bpf_ktime_get_coarse_ns_proto;
+	case BPF_FUNC_perf_event_output:
+		return &bpf_event_output_data_proto;
+	default:
+		return bpf_base_func_proto(func_id);
+	}
+}
+
+static bool sysctl_is_valid_access(int off, int size, enum bpf_access_type type,
+				   const struct bpf_prog *prog,
+				   struct bpf_insn_access_aux *info)
+{
+	const int size_default = sizeof(__u32);
+
+	if (off < 0 || off + size > sizeof(struct bpf_sysctl) || off % size)
+		return false;
+
+	switch (off) {
+	case bpf_ctx_range(struct bpf_sysctl, write):
+		if (type != BPF_READ)
+			return false;
+		bpf_ctx_record_field_size(info, size_default);
+		return bpf_ctx_narrow_access_ok(off, size, size_default);
+	case bpf_ctx_range(struct bpf_sysctl, file_pos):
+		if (type == BPF_READ) {
+			bpf_ctx_record_field_size(info, size_default);
+			return bpf_ctx_narrow_access_ok(off, size, size_default);
+		} else {
+			return size == size_default;
+		}
+	default:
+		return false;
+	}
+}
+
+static u32 sysctl_convert_ctx_access(enum bpf_access_type type,
+				     const struct bpf_insn *si,
+				     struct bpf_insn *insn_buf,
+				     struct bpf_prog *prog, u32 *target_size)
+{
+	struct bpf_insn *insn = insn_buf;
+	u32 read_size;
+
+	switch (si->off) {
+	case offsetof(struct bpf_sysctl, write):
+		*insn++ = BPF_LDX_MEM(
+			BPF_SIZE(si->code), si->dst_reg, si->src_reg,
+			bpf_target_off(struct bpf_sysctl_kern, write,
+				       sizeof_field(struct bpf_sysctl_kern,
+						    write),
+				       target_size));
+		break;
+	case offsetof(struct bpf_sysctl, file_pos):
+		/* ppos is a pointer so it should be accessed via indirect
+		 * loads and stores. Also for stores additional temporary
+		 * register is used since neither src_reg nor dst_reg can be
+		 * overridden.
+		 */
+		if (type == BPF_WRITE) {
+			int treg = BPF_REG_9;
+
+			if (si->src_reg == treg || si->dst_reg == treg)
+				--treg;
+			if (si->src_reg == treg || si->dst_reg == treg)
+				--treg;
+			*insn++ = BPF_STX_MEM(
+				BPF_DW, si->dst_reg, treg,
+				offsetof(struct bpf_sysctl_kern, tmp_reg));
+			*insn++ = BPF_LDX_MEM(
+				BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos),
+				treg, si->dst_reg,
+				offsetof(struct bpf_sysctl_kern, ppos));
+			*insn++ = BPF_STX_MEM(
+				BPF_SIZEOF(u32), treg, si->src_reg,
+				bpf_ctx_narrow_access_offset(
+					0, sizeof(u32), sizeof(loff_t)));
+			*insn++ = BPF_LDX_MEM(
+				BPF_DW, treg, si->dst_reg,
+				offsetof(struct bpf_sysctl_kern, tmp_reg));
+		} else {
+			*insn++ = BPF_LDX_MEM(
+				BPF_FIELD_SIZEOF(struct bpf_sysctl_kern, ppos),
+				si->dst_reg, si->src_reg,
+				offsetof(struct bpf_sysctl_kern, ppos));
+			read_size = bpf_size_to_bytes(BPF_SIZE(si->code));
+			*insn++ = BPF_LDX_MEM(
+				BPF_SIZE(si->code), si->dst_reg, si->dst_reg,
+				bpf_ctx_narrow_access_offset(
+					0, read_size, sizeof(loff_t)));
+		}
+		*target_size = sizeof(u32);
+		break;
+	}
+
+	return insn - insn_buf;
+}
+
+const struct bpf_verifier_ops cg_sysctl_verifier_ops = {
+	.get_func_proto		= sysctl_func_proto,
+	.is_valid_access	= sysctl_is_valid_access,
+	.convert_ctx_access	= sysctl_convert_ctx_access,
+};
+
+const struct bpf_prog_ops cg_sysctl_prog_ops = {
+};
+
+#ifdef CONFIG_NET
+BPF_CALL_1(bpf_get_netns_cookie_sockopt, struct bpf_sockopt_kern *, ctx)
+{
+	const struct net *net = ctx ? sock_net(ctx->sk) : &init_net;
+
+	return net->net_cookie;
+}
+
+static const struct bpf_func_proto bpf_get_netns_cookie_sockopt_proto = {
+	.func		= bpf_get_netns_cookie_sockopt,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX_OR_NULL,
+};
+#endif
+
+static const struct bpf_func_proto *
+cg_sockopt_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	const struct bpf_func_proto *func_proto;
+
+	func_proto = cgroup_common_func_proto(func_id, prog);
+	if (func_proto)
+		return func_proto;
+
+	func_proto = cgroup_current_func_proto(func_id, prog);
+	if (func_proto)
+		return func_proto;
+
+	switch (func_id) {
+#ifdef CONFIG_NET
+	case BPF_FUNC_get_netns_cookie:
+		return &bpf_get_netns_cookie_sockopt_proto;
+	case BPF_FUNC_sk_storage_get:
+		return &bpf_sk_storage_get_proto;
+	case BPF_FUNC_sk_storage_delete:
+		return &bpf_sk_storage_delete_proto;
+	case BPF_FUNC_setsockopt:
+		if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT)
+			return &bpf_sk_setsockopt_proto;
+		return NULL;
+	case BPF_FUNC_getsockopt:
+		if (prog->expected_attach_type == BPF_CGROUP_SETSOCKOPT)
+			return &bpf_sk_getsockopt_proto;
+		return NULL;
+#endif
+#ifdef CONFIG_INET
+	case BPF_FUNC_tcp_sock:
+		return &bpf_tcp_sock_proto;
+#endif
+	case BPF_FUNC_perf_event_output:
+		return &bpf_event_output_data_proto;
+	default:
+		return bpf_base_func_proto(func_id);
+	}
+}
+
+static bool cg_sockopt_is_valid_access(int off, int size,
+				       enum bpf_access_type type,
+				       const struct bpf_prog *prog,
+				       struct bpf_insn_access_aux *info)
+{
+	const int size_default = sizeof(__u32);
+
+	if (off < 0 || off >= sizeof(struct bpf_sockopt))
+		return false;
+
+	if (off % size != 0)
+		return false;
+
+	if (type == BPF_WRITE) {
+		switch (off) {
+		case offsetof(struct bpf_sockopt, retval):
+			if (size != size_default)
+				return false;
+			return prog->expected_attach_type ==
+				BPF_CGROUP_GETSOCKOPT;
+		case offsetof(struct bpf_sockopt, optname):
+			fallthrough;
+		case offsetof(struct bpf_sockopt, level):
+			if (size != size_default)
+				return false;
+			return prog->expected_attach_type ==
+				BPF_CGROUP_SETSOCKOPT;
+		case offsetof(struct bpf_sockopt, optlen):
+			return size == size_default;
+		default:
+			return false;
+		}
+	}
+
+	switch (off) {
+	case offsetof(struct bpf_sockopt, sk):
+		if (size != sizeof(__u64))
+			return false;
+		info->reg_type = PTR_TO_SOCKET;
+		break;
+	case offsetof(struct bpf_sockopt, optval):
+		if (size != sizeof(__u64))
+			return false;
+		info->reg_type = PTR_TO_PACKET;
+		break;
+	case offsetof(struct bpf_sockopt, optval_end):
+		if (size != sizeof(__u64))
+			return false;
+		info->reg_type = PTR_TO_PACKET_END;
+		break;
+	case offsetof(struct bpf_sockopt, retval):
+		if (size != size_default)
+			return false;
+		return prog->expected_attach_type == BPF_CGROUP_GETSOCKOPT;
+	default:
+		if (size != size_default)
+			return false;
+		break;
+	}
+	return true;
+}
+
+#define CG_SOCKOPT_ACCESS_FIELD(T, F)					\
+	T(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, F),			\
+	  si->dst_reg, si->src_reg,					\
+	  offsetof(struct bpf_sockopt_kern, F))
+
+static u32 cg_sockopt_convert_ctx_access(enum bpf_access_type type,
+					 const struct bpf_insn *si,
+					 struct bpf_insn *insn_buf,
+					 struct bpf_prog *prog,
+					 u32 *target_size)
+{
+	struct bpf_insn *insn = insn_buf;
+
+	switch (si->off) {
+	case offsetof(struct bpf_sockopt, sk):
+		*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, sk);
+		break;
+	case offsetof(struct bpf_sockopt, level):
+		if (type == BPF_WRITE)
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, level);
+		else
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, level);
+		break;
+	case offsetof(struct bpf_sockopt, optname):
+		if (type == BPF_WRITE)
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, optname);
+		else
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optname);
+		break;
+	case offsetof(struct bpf_sockopt, optlen):
+		if (type == BPF_WRITE)
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_STX_MEM, optlen);
+		else
+			*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optlen);
+		break;
+	case offsetof(struct bpf_sockopt, retval):
+		BUILD_BUG_ON(offsetof(struct bpf_cg_run_ctx, run_ctx) != 0);
+
+		if (type == BPF_WRITE) {
+			int treg = BPF_REG_9;
+
+			if (si->src_reg == treg || si->dst_reg == treg)
+				--treg;
+			if (si->src_reg == treg || si->dst_reg == treg)
+				--treg;
+			*insn++ = BPF_STX_MEM(BPF_DW, si->dst_reg, treg,
+					      offsetof(struct bpf_sockopt_kern, tmp_reg));
+			*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, current_task),
+					      treg, si->dst_reg,
+					      offsetof(struct bpf_sockopt_kern, current_task));
+			*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct task_struct, bpf_ctx),
+					      treg, treg,
+					      offsetof(struct task_struct, bpf_ctx));
+			*insn++ = BPF_STX_MEM(BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval),
+					      treg, si->src_reg,
+					      offsetof(struct bpf_cg_run_ctx, retval));
+			*insn++ = BPF_LDX_MEM(BPF_DW, treg, si->dst_reg,
+					      offsetof(struct bpf_sockopt_kern, tmp_reg));
+		} else {
+			*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sockopt_kern, current_task),
+					      si->dst_reg, si->src_reg,
+					      offsetof(struct bpf_sockopt_kern, current_task));
+			*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct task_struct, bpf_ctx),
+					      si->dst_reg, si->dst_reg,
+					      offsetof(struct task_struct, bpf_ctx));
+			*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_cg_run_ctx, retval),
+					      si->dst_reg, si->dst_reg,
+					      offsetof(struct bpf_cg_run_ctx, retval));
+		}
+		break;
+	case offsetof(struct bpf_sockopt, optval):
+		*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optval);
+		break;
+	case offsetof(struct bpf_sockopt, optval_end):
+		*insn++ = CG_SOCKOPT_ACCESS_FIELD(BPF_LDX_MEM, optval_end);
+		break;
+	}
+
+	return insn - insn_buf;
+}
+
+static int cg_sockopt_get_prologue(struct bpf_insn *insn_buf,
+				   bool direct_write,
+				   const struct bpf_prog *prog)
+{
+	/* Nothing to do for sockopt argument. The data is kzalloc'ated.
+	 */
+	return 0;
+}
+
+const struct bpf_verifier_ops cg_sockopt_verifier_ops = {
+	.get_func_proto		= cg_sockopt_func_proto,
+	.is_valid_access	= cg_sockopt_is_valid_access,
+	.convert_ctx_access	= cg_sockopt_convert_ctx_access,
+	.gen_prologue		= cg_sockopt_get_prologue,
+};
+
+const struct bpf_prog_ops cg_sockopt_prog_ops = {
+};
+
+/* Common helpers for cgroup hooks. */
+const struct bpf_func_proto *
+cgroup_common_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	switch (func_id) {
+	case BPF_FUNC_get_local_storage:
+		return &bpf_get_local_storage_proto;
+	case BPF_FUNC_get_retval:
+		switch (prog->expected_attach_type) {
+		case BPF_CGROUP_INET_INGRESS:
+		case BPF_CGROUP_INET_EGRESS:
+		case BPF_CGROUP_SOCK_OPS:
+		case BPF_CGROUP_UDP4_RECVMSG:
+		case BPF_CGROUP_UDP6_RECVMSG:
+		case BPF_CGROUP_INET4_GETPEERNAME:
+		case BPF_CGROUP_INET6_GETPEERNAME:
+		case BPF_CGROUP_INET4_GETSOCKNAME:
+		case BPF_CGROUP_INET6_GETSOCKNAME:
+			return NULL;
+		default:
+			return &bpf_get_retval_proto;
+		}
+	case BPF_FUNC_set_retval:
+		switch (prog->expected_attach_type) {
+		case BPF_CGROUP_INET_INGRESS:
+		case BPF_CGROUP_INET_EGRESS:
+		case BPF_CGROUP_SOCK_OPS:
+		case BPF_CGROUP_UDP4_RECVMSG:
+		case BPF_CGROUP_UDP6_RECVMSG:
+		case BPF_CGROUP_INET4_GETPEERNAME:
+		case BPF_CGROUP_INET6_GETPEERNAME:
+		case BPF_CGROUP_INET4_GETSOCKNAME:
+		case BPF_CGROUP_INET6_GETSOCKNAME:
+			return NULL;
+		default:
+			return &bpf_set_retval_proto;
+		}
+	default:
+		return NULL;
+	}
+}
+
+/* Common helpers for cgroup hooks with valid process context. */
+const struct bpf_func_proto *
+cgroup_current_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	switch (func_id) {
+	case BPF_FUNC_get_current_uid_gid:
+		return &bpf_get_current_uid_gid_proto;
+	case BPF_FUNC_get_current_pid_tgid:
+		return &bpf_get_current_pid_tgid_proto;
+	case BPF_FUNC_get_current_comm:
+		return &bpf_get_current_comm_proto;
+	case BPF_FUNC_get_current_cgroup_id:
+		return &bpf_get_current_cgroup_id_proto;
+	case BPF_FUNC_get_current_ancestor_cgroup_id:
+		return &bpf_get_current_ancestor_cgroup_id_proto;
+#ifdef CONFIG_CGROUP_NET_CLASSID
+	case BPF_FUNC_get_cgroup_classid:
+		return &bpf_get_cgroup_classid_curr_proto;
+#endif
+	default:
+		return NULL;
+	}
+}
diff --git a/kernel/bpf/cgroup_iter.c b/kernel/bpf/cgroup_iter.c
new file mode 100644
index 000000000..d57ccb024
--- /dev/null
+++ b/kernel/bpf/cgroup_iter.c
@@ -0,0 +1,296 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2022 Google */
+#include <linux/bpf.h>
+#include <linux/btf_ids.h>
+#include <linux/cgroup.h>
+#include <linux/kernel.h>
+#include <linux/seq_file.h>
+
+#include "../cgroup/cgroup-internal.h"  /* cgroup_mutex and cgroup_is_dead */
+
+/* cgroup_iter provides four modes of traversal to the cgroup hierarchy.
+ *
+ *  1. Walk the descendants of a cgroup in pre-order.
+ *  2. Walk the descendants of a cgroup in post-order.
+ *  3. Walk the ancestors of a cgroup.
+ *  4. Show the given cgroup only.
+ *
+ * For walking descendants, cgroup_iter can walk in either pre-order or
+ * post-order. For walking ancestors, the iter walks up from a cgroup to
+ * the root.
+ *
+ * The iter program can terminate the walk early by returning 1. Walk
+ * continues if prog returns 0.
+ *
+ * The prog can check (seq->num == 0) to determine whether this is
+ * the first element. The prog may also be passed a NULL cgroup,
+ * which means the walk has completed and the prog has a chance to
+ * do post-processing, such as outputting an epilogue.
+ *
+ * Note: the iter_prog is called with cgroup_mutex held.
+ *
+ * Currently only one session is supported, which means, depending on the
+ * volume of data bpf program intends to send to user space, the number
+ * of cgroups that can be walked is limited. For example, given the current
+ * buffer size is 8 * PAGE_SIZE, if the program sends 64B data for each
+ * cgroup, assuming PAGE_SIZE is 4kb, the total number of cgroups that can
+ * be walked is 512. This is a limitation of cgroup_iter. If the output data
+ * is larger than the kernel buffer size, after all data in the kernel buffer
+ * is consumed by user space, the subsequent read() syscall will signal
+ * EOPNOTSUPP. In order to work around, the user may have to update their
+ * program to reduce the volume of data sent to output. For example, skip
+ * some uninteresting cgroups.
+ */
+
+struct bpf_iter__cgroup {
+	__bpf_md_ptr(struct bpf_iter_meta *, meta);
+	__bpf_md_ptr(struct cgroup *, cgroup);
+};
+
+struct cgroup_iter_priv {
+	struct cgroup_subsys_state *start_css;
+	bool visited_all;
+	bool terminate;
+	int order;
+};
+
+static void *cgroup_iter_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct cgroup_iter_priv *p = seq->private;
+
+	cgroup_lock();
+
+	/* cgroup_iter doesn't support read across multiple sessions. */
+	if (*pos > 0) {
+		if (p->visited_all)
+			return NULL;
+
+		/* Haven't visited all, but because cgroup_mutex has dropped,
+		 * return -EOPNOTSUPP to indicate incomplete iteration.
+		 */
+		return ERR_PTR(-EOPNOTSUPP);
+	}
+
+	++*pos;
+	p->terminate = false;
+	p->visited_all = false;
+	if (p->order == BPF_CGROUP_ITER_DESCENDANTS_PRE)
+		return css_next_descendant_pre(NULL, p->start_css);
+	else if (p->order == BPF_CGROUP_ITER_DESCENDANTS_POST)
+		return css_next_descendant_post(NULL, p->start_css);
+	else /* BPF_CGROUP_ITER_SELF_ONLY and BPF_CGROUP_ITER_ANCESTORS_UP */
+		return p->start_css;
+}
+
+static int __cgroup_iter_seq_show(struct seq_file *seq,
+				  struct cgroup_subsys_state *css, int in_stop);
+
+static void cgroup_iter_seq_stop(struct seq_file *seq, void *v)
+{
+	struct cgroup_iter_priv *p = seq->private;
+
+	cgroup_unlock();
+
+	/* pass NULL to the prog for post-processing */
+	if (!v) {
+		__cgroup_iter_seq_show(seq, NULL, true);
+		p->visited_all = true;
+	}
+}
+
+static void *cgroup_iter_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct cgroup_subsys_state *curr = (struct cgroup_subsys_state *)v;
+	struct cgroup_iter_priv *p = seq->private;
+
+	++*pos;
+	if (p->terminate)
+		return NULL;
+
+	if (p->order == BPF_CGROUP_ITER_DESCENDANTS_PRE)
+		return css_next_descendant_pre(curr, p->start_css);
+	else if (p->order == BPF_CGROUP_ITER_DESCENDANTS_POST)
+		return css_next_descendant_post(curr, p->start_css);
+	else if (p->order == BPF_CGROUP_ITER_ANCESTORS_UP)
+		return curr->parent;
+	else  /* BPF_CGROUP_ITER_SELF_ONLY */
+		return NULL;
+}
+
+static int __cgroup_iter_seq_show(struct seq_file *seq,
+				  struct cgroup_subsys_state *css, int in_stop)
+{
+	struct cgroup_iter_priv *p = seq->private;
+	struct bpf_iter__cgroup ctx;
+	struct bpf_iter_meta meta;
+	struct bpf_prog *prog;
+	int ret = 0;
+
+	/* cgroup is dead, skip this element */
+	if (css && cgroup_is_dead(css->cgroup))
+		return 0;
+
+	ctx.meta = &meta;
+	ctx.cgroup = css ? css->cgroup : NULL;
+	meta.seq = seq;
+	prog = bpf_iter_get_info(&meta, in_stop);
+	if (prog)
+		ret = bpf_iter_run_prog(prog, &ctx);
+
+	/* if prog returns > 0, terminate after this element. */
+	if (ret != 0)
+		p->terminate = true;
+
+	return 0;
+}
+
+static int cgroup_iter_seq_show(struct seq_file *seq, void *v)
+{
+	return __cgroup_iter_seq_show(seq, (struct cgroup_subsys_state *)v,
+				      false);
+}
+
+static const struct seq_operations cgroup_iter_seq_ops = {
+	.start  = cgroup_iter_seq_start,
+	.next   = cgroup_iter_seq_next,
+	.stop   = cgroup_iter_seq_stop,
+	.show   = cgroup_iter_seq_show,
+};
+
+BTF_ID_LIST_SINGLE(bpf_cgroup_btf_id, struct, cgroup)
+
+static int cgroup_iter_seq_init(void *priv, struct bpf_iter_aux_info *aux)
+{
+	struct cgroup_iter_priv *p = (struct cgroup_iter_priv *)priv;
+	struct cgroup *cgrp = aux->cgroup.start;
+
+	/* bpf_iter_attach_cgroup() has already acquired an extra reference
+	 * for the start cgroup, but the reference may be released after
+	 * cgroup_iter_seq_init(), so acquire another reference for the
+	 * start cgroup.
+	 */
+	p->start_css = &cgrp->self;
+	css_get(p->start_css);
+	p->terminate = false;
+	p->visited_all = false;
+	p->order = aux->cgroup.order;
+	return 0;
+}
+
+static void cgroup_iter_seq_fini(void *priv)
+{
+	struct cgroup_iter_priv *p = (struct cgroup_iter_priv *)priv;
+
+	css_put(p->start_css);
+}
+
+static const struct bpf_iter_seq_info cgroup_iter_seq_info = {
+	.seq_ops		= &cgroup_iter_seq_ops,
+	.init_seq_private	= cgroup_iter_seq_init,
+	.fini_seq_private	= cgroup_iter_seq_fini,
+	.seq_priv_size		= sizeof(struct cgroup_iter_priv),
+};
+
+static int bpf_iter_attach_cgroup(struct bpf_prog *prog,
+				  union bpf_iter_link_info *linfo,
+				  struct bpf_iter_aux_info *aux)
+{
+	int fd = linfo->cgroup.cgroup_fd;
+	u64 id = linfo->cgroup.cgroup_id;
+	int order = linfo->cgroup.order;
+	struct cgroup *cgrp;
+
+	if (order != BPF_CGROUP_ITER_DESCENDANTS_PRE &&
+	    order != BPF_CGROUP_ITER_DESCENDANTS_POST &&
+	    order != BPF_CGROUP_ITER_ANCESTORS_UP &&
+	    order != BPF_CGROUP_ITER_SELF_ONLY)
+		return -EINVAL;
+
+	if (fd && id)
+		return -EINVAL;
+
+	if (fd)
+		cgrp = cgroup_v1v2_get_from_fd(fd);
+	else if (id)
+		cgrp = cgroup_get_from_id(id);
+	else /* walk the entire hierarchy by default. */
+		cgrp = cgroup_get_from_path("/");
+
+	if (IS_ERR(cgrp))
+		return PTR_ERR(cgrp);
+
+	aux->cgroup.start = cgrp;
+	aux->cgroup.order = order;
+	return 0;
+}
+
+static void bpf_iter_detach_cgroup(struct bpf_iter_aux_info *aux)
+{
+	cgroup_put(aux->cgroup.start);
+}
+
+static void bpf_iter_cgroup_show_fdinfo(const struct bpf_iter_aux_info *aux,
+					struct seq_file *seq)
+{
+	char *buf;
+
+	buf = kzalloc(PATH_MAX, GFP_KERNEL);
+	if (!buf) {
+		seq_puts(seq, "cgroup_path:\t<unknown>\n");
+		goto show_order;
+	}
+
+	/* If cgroup_path_ns() fails, buf will be an empty string, cgroup_path
+	 * will print nothing.
+	 *
+	 * Path is in the calling process's cgroup namespace.
+	 */
+	cgroup_path_ns(aux->cgroup.start, buf, PATH_MAX,
+		       current->nsproxy->cgroup_ns);
+	seq_printf(seq, "cgroup_path:\t%s\n", buf);
+	kfree(buf);
+
+show_order:
+	if (aux->cgroup.order == BPF_CGROUP_ITER_DESCENDANTS_PRE)
+		seq_puts(seq, "order: descendants_pre\n");
+	else if (aux->cgroup.order == BPF_CGROUP_ITER_DESCENDANTS_POST)
+		seq_puts(seq, "order: descendants_post\n");
+	else if (aux->cgroup.order == BPF_CGROUP_ITER_ANCESTORS_UP)
+		seq_puts(seq, "order: ancestors_up\n");
+	else /* BPF_CGROUP_ITER_SELF_ONLY */
+		seq_puts(seq, "order: self_only\n");
+}
+
+static int bpf_iter_cgroup_fill_link_info(const struct bpf_iter_aux_info *aux,
+					  struct bpf_link_info *info)
+{
+	info->iter.cgroup.order = aux->cgroup.order;
+	info->iter.cgroup.cgroup_id = cgroup_id(aux->cgroup.start);
+	return 0;
+}
+
+DEFINE_BPF_ITER_FUNC(cgroup, struct bpf_iter_meta *meta,
+		     struct cgroup *cgroup)
+
+static struct bpf_iter_reg bpf_cgroup_reg_info = {
+	.target			= "cgroup",
+	.feature		= BPF_ITER_RESCHED,
+	.attach_target		= bpf_iter_attach_cgroup,
+	.detach_target		= bpf_iter_detach_cgroup,
+	.show_fdinfo		= bpf_iter_cgroup_show_fdinfo,
+	.fill_link_info		= bpf_iter_cgroup_fill_link_info,
+	.ctx_arg_info_size	= 1,
+	.ctx_arg_info		= {
+		{ offsetof(struct bpf_iter__cgroup, cgroup),
+		  PTR_TO_BTF_ID_OR_NULL },
+	},
+	.seq_info		= &cgroup_iter_seq_info,
+};
+
+static int __init bpf_cgroup_iter_init(void)
+{
+	bpf_cgroup_reg_info.ctx_arg_info[0].btf_id = bpf_cgroup_btf_id[0];
+	return bpf_iter_reg_target(&bpf_cgroup_reg_info);
+}
+
+late_initcall(bpf_cgroup_iter_init);
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
new file mode 100644
index 000000000..76bf1de26
--- /dev/null
+++ b/kernel/bpf/core.c
@@ -0,0 +1,2772 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Linux Socket Filter - Kernel level socket filtering
+ *
+ * Based on the design of the Berkeley Packet Filter. The new
+ * internal format has been designed by PLUMgrid:
+ *
+ *	Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
+ *
+ * Authors:
+ *
+ *	Jay Schulist <jschlst@samba.org>
+ *	Alexei Starovoitov <ast@plumgrid.com>
+ *	Daniel Borkmann <dborkman@redhat.com>
+ *
+ * Andi Kleen - Fix a few bad bugs and races.
+ * Kris Katterjohn - Added many additional checks in bpf_check_classic()
+ */
+
+#include <uapi/linux/btf.h>
+#include <linux/filter.h>
+#include <linux/skbuff.h>
+#include <linux/vmalloc.h>
+#include <linux/random.h>
+#include <linux/moduleloader.h>
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/objtool.h>
+#include <linux/rbtree_latch.h>
+#include <linux/kallsyms.h>
+#include <linux/rcupdate.h>
+#include <linux/perf_event.h>
+#include <linux/extable.h>
+#include <linux/log2.h>
+#include <linux/bpf_verifier.h>
+#include <linux/nodemask.h>
+#include <linux/nospec.h>
+
+#include <asm/barrier.h>
+#include <asm/unaligned.h>
+
+/* Registers */
+#define BPF_R0	regs[BPF_REG_0]
+#define BPF_R1	regs[BPF_REG_1]
+#define BPF_R2	regs[BPF_REG_2]
+#define BPF_R3	regs[BPF_REG_3]
+#define BPF_R4	regs[BPF_REG_4]
+#define BPF_R5	regs[BPF_REG_5]
+#define BPF_R6	regs[BPF_REG_6]
+#define BPF_R7	regs[BPF_REG_7]
+#define BPF_R8	regs[BPF_REG_8]
+#define BPF_R9	regs[BPF_REG_9]
+#define BPF_R10	regs[BPF_REG_10]
+
+/* Named registers */
+#define DST	regs[insn->dst_reg]
+#define SRC	regs[insn->src_reg]
+#define FP	regs[BPF_REG_FP]
+#define AX	regs[BPF_REG_AX]
+#define ARG1	regs[BPF_REG_ARG1]
+#define CTX	regs[BPF_REG_CTX]
+#define IMM	insn->imm
+
+/* No hurry in this branch
+ *
+ * Exported for the bpf jit load helper.
+ */
+void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
+{
+	u8 *ptr = NULL;
+
+	if (k >= SKF_NET_OFF) {
+		ptr = skb_network_header(skb) + k - SKF_NET_OFF;
+	} else if (k >= SKF_LL_OFF) {
+		if (unlikely(!skb_mac_header_was_set(skb)))
+			return NULL;
+		ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
+	}
+	if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
+		return ptr;
+
+	return NULL;
+}
+
+struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags)
+{
+	gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags;
+	struct bpf_prog_aux *aux;
+	struct bpf_prog *fp;
+
+	size = round_up(size, PAGE_SIZE);
+	fp = __vmalloc(size, gfp_flags);
+	if (fp == NULL)
+		return NULL;
+
+	aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT | gfp_extra_flags);
+	if (aux == NULL) {
+		vfree(fp);
+		return NULL;
+	}
+	fp->active = alloc_percpu_gfp(int, GFP_KERNEL_ACCOUNT | gfp_extra_flags);
+	if (!fp->active) {
+		vfree(fp);
+		kfree(aux);
+		return NULL;
+	}
+
+	fp->pages = size / PAGE_SIZE;
+	fp->aux = aux;
+	fp->aux->prog = fp;
+	fp->jit_requested = ebpf_jit_enabled();
+	fp->blinding_requested = bpf_jit_blinding_enabled(fp);
+#ifdef CONFIG_CGROUP_BPF
+	aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID;
+#endif
+
+	INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode);
+	mutex_init(&fp->aux->used_maps_mutex);
+	mutex_init(&fp->aux->dst_mutex);
+
+	return fp;
+}
+
+struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
+{
+	gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags;
+	struct bpf_prog *prog;
+	int cpu;
+
+	prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags);
+	if (!prog)
+		return NULL;
+
+	prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags);
+	if (!prog->stats) {
+		free_percpu(prog->active);
+		kfree(prog->aux);
+		vfree(prog);
+		return NULL;
+	}
+
+	for_each_possible_cpu(cpu) {
+		struct bpf_prog_stats *pstats;
+
+		pstats = per_cpu_ptr(prog->stats, cpu);
+		u64_stats_init(&pstats->syncp);
+	}
+	return prog;
+}
+EXPORT_SYMBOL_GPL(bpf_prog_alloc);
+
+int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog)
+{
+	if (!prog->aux->nr_linfo || !prog->jit_requested)
+		return 0;
+
+	prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo,
+					  sizeof(*prog->aux->jited_linfo),
+					  GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
+	if (!prog->aux->jited_linfo)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void bpf_prog_jit_attempt_done(struct bpf_prog *prog)
+{
+	if (prog->aux->jited_linfo &&
+	    (!prog->jited || !prog->aux->jited_linfo[0])) {
+		kvfree(prog->aux->jited_linfo);
+		prog->aux->jited_linfo = NULL;
+	}
+
+	kfree(prog->aux->kfunc_tab);
+	prog->aux->kfunc_tab = NULL;
+}
+
+/* The jit engine is responsible to provide an array
+ * for insn_off to the jited_off mapping (insn_to_jit_off).
+ *
+ * The idx to this array is the insn_off.  Hence, the insn_off
+ * here is relative to the prog itself instead of the main prog.
+ * This array has one entry for each xlated bpf insn.
+ *
+ * jited_off is the byte off to the end of the jited insn.
+ *
+ * Hence, with
+ * insn_start:
+ *      The first bpf insn off of the prog.  The insn off
+ *      here is relative to the main prog.
+ *      e.g. if prog is a subprog, insn_start > 0
+ * linfo_idx:
+ *      The prog's idx to prog->aux->linfo and jited_linfo
+ *
+ * jited_linfo[linfo_idx] = prog->bpf_func
+ *
+ * For i > linfo_idx,
+ *
+ * jited_linfo[i] = prog->bpf_func +
+ *	insn_to_jit_off[linfo[i].insn_off - insn_start - 1]
+ */
+void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,
+			       const u32 *insn_to_jit_off)
+{
+	u32 linfo_idx, insn_start, insn_end, nr_linfo, i;
+	const struct bpf_line_info *linfo;
+	void **jited_linfo;
+
+	if (!prog->aux->jited_linfo)
+		/* Userspace did not provide linfo */
+		return;
+
+	linfo_idx = prog->aux->linfo_idx;
+	linfo = &prog->aux->linfo[linfo_idx];
+	insn_start = linfo[0].insn_off;
+	insn_end = insn_start + prog->len;
+
+	jited_linfo = &prog->aux->jited_linfo[linfo_idx];
+	jited_linfo[0] = prog->bpf_func;
+
+	nr_linfo = prog->aux->nr_linfo - linfo_idx;
+
+	for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++)
+		/* The verifier ensures that linfo[i].insn_off is
+		 * strictly increasing
+		 */
+		jited_linfo[i] = prog->bpf_func +
+			insn_to_jit_off[linfo[i].insn_off - insn_start - 1];
+}
+
+struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
+				  gfp_t gfp_extra_flags)
+{
+	gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags;
+	struct bpf_prog *fp;
+	u32 pages;
+
+	size = round_up(size, PAGE_SIZE);
+	pages = size / PAGE_SIZE;
+	if (pages <= fp_old->pages)
+		return fp_old;
+
+	fp = __vmalloc(size, gfp_flags);
+	if (fp) {
+		memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
+		fp->pages = pages;
+		fp->aux->prog = fp;
+
+		/* We keep fp->aux from fp_old around in the new
+		 * reallocated structure.
+		 */
+		fp_old->aux = NULL;
+		fp_old->stats = NULL;
+		fp_old->active = NULL;
+		__bpf_prog_free(fp_old);
+	}
+
+	return fp;
+}
+
+void __bpf_prog_free(struct bpf_prog *fp)
+{
+	if (fp->aux) {
+		mutex_destroy(&fp->aux->used_maps_mutex);
+		mutex_destroy(&fp->aux->dst_mutex);
+		kfree(fp->aux->poke_tab);
+		kfree(fp->aux);
+	}
+	free_percpu(fp->stats);
+	free_percpu(fp->active);
+	vfree(fp);
+}
+
+int bpf_prog_calc_tag(struct bpf_prog *fp)
+{
+	const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
+	u32 raw_size = bpf_prog_tag_scratch_size(fp);
+	u32 digest[SHA1_DIGEST_WORDS];
+	u32 ws[SHA1_WORKSPACE_WORDS];
+	u32 i, bsize, psize, blocks;
+	struct bpf_insn *dst;
+	bool was_ld_map;
+	u8 *raw, *todo;
+	__be32 *result;
+	__be64 *bits;
+
+	raw = vmalloc(raw_size);
+	if (!raw)
+		return -ENOMEM;
+
+	sha1_init(digest);
+	memset(ws, 0, sizeof(ws));
+
+	/* We need to take out the map fd for the digest calculation
+	 * since they are unstable from user space side.
+	 */
+	dst = (void *)raw;
+	for (i = 0, was_ld_map = false; i < fp->len; i++) {
+		dst[i] = fp->insnsi[i];
+		if (!was_ld_map &&
+		    dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
+		    (dst[i].src_reg == BPF_PSEUDO_MAP_FD ||
+		     dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) {
+			was_ld_map = true;
+			dst[i].imm = 0;
+		} else if (was_ld_map &&
+			   dst[i].code == 0 &&
+			   dst[i].dst_reg == 0 &&
+			   dst[i].src_reg == 0 &&
+			   dst[i].off == 0) {
+			was_ld_map = false;
+			dst[i].imm = 0;
+		} else {
+			was_ld_map = false;
+		}
+	}
+
+	psize = bpf_prog_insn_size(fp);
+	memset(&raw[psize], 0, raw_size - psize);
+	raw[psize++] = 0x80;
+
+	bsize  = round_up(psize, SHA1_BLOCK_SIZE);
+	blocks = bsize / SHA1_BLOCK_SIZE;
+	todo   = raw;
+	if (bsize - psize >= sizeof(__be64)) {
+		bits = (__be64 *)(todo + bsize - sizeof(__be64));
+	} else {
+		bits = (__be64 *)(todo + bsize + bits_offset);
+		blocks++;
+	}
+	*bits = cpu_to_be64((psize - 1) << 3);
+
+	while (blocks--) {
+		sha1_transform(digest, todo, ws);
+		todo += SHA1_BLOCK_SIZE;
+	}
+
+	result = (__force __be32 *)digest;
+	for (i = 0; i < SHA1_DIGEST_WORDS; i++)
+		result[i] = cpu_to_be32(digest[i]);
+	memcpy(fp->tag, result, sizeof(fp->tag));
+
+	vfree(raw);
+	return 0;
+}
+
+static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old,
+				s32 end_new, s32 curr, const bool probe_pass)
+{
+	const s64 imm_min = S32_MIN, imm_max = S32_MAX;
+	s32 delta = end_new - end_old;
+	s64 imm = insn->imm;
+
+	if (curr < pos && curr + imm + 1 >= end_old)
+		imm += delta;
+	else if (curr >= end_new && curr + imm + 1 < end_new)
+		imm -= delta;
+	if (imm < imm_min || imm > imm_max)
+		return -ERANGE;
+	if (!probe_pass)
+		insn->imm = imm;
+	return 0;
+}
+
+static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old,
+				s32 end_new, s32 curr, const bool probe_pass)
+{
+	s64 off_min, off_max, off;
+	s32 delta = end_new - end_old;
+
+	if (insn->code == (BPF_JMP32 | BPF_JA)) {
+		off = insn->imm;
+		off_min = S32_MIN;
+		off_max = S32_MAX;
+	} else {
+		off = insn->off;
+		off_min = S16_MIN;
+		off_max = S16_MAX;
+	}
+
+	if (curr < pos && curr + off + 1 >= end_old)
+		off += delta;
+	else if (curr >= end_new && curr + off + 1 < end_new)
+		off -= delta;
+	if (off < off_min || off > off_max)
+		return -ERANGE;
+	if (!probe_pass) {
+		if (insn->code == (BPF_JMP32 | BPF_JA))
+			insn->imm = off;
+		else
+			insn->off = off;
+	}
+	return 0;
+}
+
+static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old,
+			    s32 end_new, const bool probe_pass)
+{
+	u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0);
+	struct bpf_insn *insn = prog->insnsi;
+	int ret = 0;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		u8 code;
+
+		/* In the probing pass we still operate on the original,
+		 * unpatched image in order to check overflows before we
+		 * do any other adjustments. Therefore skip the patchlet.
+		 */
+		if (probe_pass && i == pos) {
+			i = end_new;
+			insn = prog->insnsi + end_old;
+		}
+		if (bpf_pseudo_func(insn)) {
+			ret = bpf_adj_delta_to_imm(insn, pos, end_old,
+						   end_new, i, probe_pass);
+			if (ret)
+				return ret;
+			continue;
+		}
+		code = insn->code;
+		if ((BPF_CLASS(code) != BPF_JMP &&
+		     BPF_CLASS(code) != BPF_JMP32) ||
+		    BPF_OP(code) == BPF_EXIT)
+			continue;
+		/* Adjust offset of jmps if we cross patch boundaries. */
+		if (BPF_OP(code) == BPF_CALL) {
+			if (insn->src_reg != BPF_PSEUDO_CALL)
+				continue;
+			ret = bpf_adj_delta_to_imm(insn, pos, end_old,
+						   end_new, i, probe_pass);
+		} else {
+			ret = bpf_adj_delta_to_off(insn, pos, end_old,
+						   end_new, i, probe_pass);
+		}
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta)
+{
+	struct bpf_line_info *linfo;
+	u32 i, nr_linfo;
+
+	nr_linfo = prog->aux->nr_linfo;
+	if (!nr_linfo || !delta)
+		return;
+
+	linfo = prog->aux->linfo;
+
+	for (i = 0; i < nr_linfo; i++)
+		if (off < linfo[i].insn_off)
+			break;
+
+	/* Push all off < linfo[i].insn_off by delta */
+	for (; i < nr_linfo; i++)
+		linfo[i].insn_off += delta;
+}
+
+struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
+				       const struct bpf_insn *patch, u32 len)
+{
+	u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
+	const u32 cnt_max = S16_MAX;
+	struct bpf_prog *prog_adj;
+	int err;
+
+	/* Since our patchlet doesn't expand the image, we're done. */
+	if (insn_delta == 0) {
+		memcpy(prog->insnsi + off, patch, sizeof(*patch));
+		return prog;
+	}
+
+	insn_adj_cnt = prog->len + insn_delta;
+
+	/* Reject anything that would potentially let the insn->off
+	 * target overflow when we have excessive program expansions.
+	 * We need to probe here before we do any reallocation where
+	 * we afterwards may not fail anymore.
+	 */
+	if (insn_adj_cnt > cnt_max &&
+	    (err = bpf_adj_branches(prog, off, off + 1, off + len, true)))
+		return ERR_PTR(err);
+
+	/* Several new instructions need to be inserted. Make room
+	 * for them. Likely, there's no need for a new allocation as
+	 * last page could have large enough tailroom.
+	 */
+	prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
+				    GFP_USER);
+	if (!prog_adj)
+		return ERR_PTR(-ENOMEM);
+
+	prog_adj->len = insn_adj_cnt;
+
+	/* Patching happens in 3 steps:
+	 *
+	 * 1) Move over tail of insnsi from next instruction onwards,
+	 *    so we can patch the single target insn with one or more
+	 *    new ones (patching is always from 1 to n insns, n > 0).
+	 * 2) Inject new instructions at the target location.
+	 * 3) Adjust branch offsets if necessary.
+	 */
+	insn_rest = insn_adj_cnt - off - len;
+
+	memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
+		sizeof(*patch) * insn_rest);
+	memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
+
+	/* We are guaranteed to not fail at this point, otherwise
+	 * the ship has sailed to reverse to the original state. An
+	 * overflow cannot happen at this point.
+	 */
+	BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false));
+
+	bpf_adj_linfo(prog_adj, off, insn_delta);
+
+	return prog_adj;
+}
+
+int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt)
+{
+	/* Branch offsets can't overflow when program is shrinking, no need
+	 * to call bpf_adj_branches(..., true) here
+	 */
+	memmove(prog->insnsi + off, prog->insnsi + off + cnt,
+		sizeof(struct bpf_insn) * (prog->len - off - cnt));
+	prog->len -= cnt;
+
+	return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false));
+}
+
+static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)
+{
+	int i;
+
+	for (i = 0; i < fp->aux->func_cnt; i++)
+		bpf_prog_kallsyms_del(fp->aux->func[i]);
+}
+
+void bpf_prog_kallsyms_del_all(struct bpf_prog *fp)
+{
+	bpf_prog_kallsyms_del_subprogs(fp);
+	bpf_prog_kallsyms_del(fp);
+}
+
+#ifdef CONFIG_BPF_JIT
+/* All BPF JIT sysctl knobs here. */
+int bpf_jit_enable   __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
+int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
+int bpf_jit_harden   __read_mostly;
+long bpf_jit_limit   __read_mostly;
+long bpf_jit_limit_max __read_mostly;
+
+static void
+bpf_prog_ksym_set_addr(struct bpf_prog *prog)
+{
+	WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
+
+	prog->aux->ksym.start = (unsigned long) prog->bpf_func;
+	prog->aux->ksym.end   = prog->aux->ksym.start + prog->jited_len;
+}
+
+static void
+bpf_prog_ksym_set_name(struct bpf_prog *prog)
+{
+	char *sym = prog->aux->ksym.name;
+	const char *end = sym + KSYM_NAME_LEN;
+	const struct btf_type *type;
+	const char *func_name;
+
+	BUILD_BUG_ON(sizeof("bpf_prog_") +
+		     sizeof(prog->tag) * 2 +
+		     /* name has been null terminated.
+		      * We should need +1 for the '_' preceding
+		      * the name.  However, the null character
+		      * is double counted between the name and the
+		      * sizeof("bpf_prog_") above, so we omit
+		      * the +1 here.
+		      */
+		     sizeof(prog->aux->name) > KSYM_NAME_LEN);
+
+	sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
+	sym  = bin2hex(sym, prog->tag, sizeof(prog->tag));
+
+	/* prog->aux->name will be ignored if full btf name is available */
+	if (prog->aux->func_info_cnt) {
+		type = btf_type_by_id(prog->aux->btf,
+				      prog->aux->func_info[prog->aux->func_idx].type_id);
+		func_name = btf_name_by_offset(prog->aux->btf, type->name_off);
+		snprintf(sym, (size_t)(end - sym), "_%s", func_name);
+		return;
+	}
+
+	if (prog->aux->name[0])
+		snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
+	else
+		*sym = 0;
+}
+
+static unsigned long bpf_get_ksym_start(struct latch_tree_node *n)
+{
+	return container_of(n, struct bpf_ksym, tnode)->start;
+}
+
+static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
+					  struct latch_tree_node *b)
+{
+	return bpf_get_ksym_start(a) < bpf_get_ksym_start(b);
+}
+
+static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
+{
+	unsigned long val = (unsigned long)key;
+	const struct bpf_ksym *ksym;
+
+	ksym = container_of(n, struct bpf_ksym, tnode);
+
+	if (val < ksym->start)
+		return -1;
+	/* Ensure that we detect return addresses as part of the program, when
+	 * the final instruction is a call for a program part of the stack
+	 * trace. Therefore, do val > ksym->end instead of val >= ksym->end.
+	 */
+	if (val > ksym->end)
+		return  1;
+
+	return 0;
+}
+
+static const struct latch_tree_ops bpf_tree_ops = {
+	.less	= bpf_tree_less,
+	.comp	= bpf_tree_comp,
+};
+
+static DEFINE_SPINLOCK(bpf_lock);
+static LIST_HEAD(bpf_kallsyms);
+static struct latch_tree_root bpf_tree __cacheline_aligned;
+
+void bpf_ksym_add(struct bpf_ksym *ksym)
+{
+	spin_lock_bh(&bpf_lock);
+	WARN_ON_ONCE(!list_empty(&ksym->lnode));
+	list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms);
+	latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
+	spin_unlock_bh(&bpf_lock);
+}
+
+static void __bpf_ksym_del(struct bpf_ksym *ksym)
+{
+	if (list_empty(&ksym->lnode))
+		return;
+
+	latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
+	list_del_rcu(&ksym->lnode);
+}
+
+void bpf_ksym_del(struct bpf_ksym *ksym)
+{
+	spin_lock_bh(&bpf_lock);
+	__bpf_ksym_del(ksym);
+	spin_unlock_bh(&bpf_lock);
+}
+
+static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
+{
+	return fp->jited && !bpf_prog_was_classic(fp);
+}
+
+void bpf_prog_kallsyms_add(struct bpf_prog *fp)
+{
+	if (!bpf_prog_kallsyms_candidate(fp) ||
+	    !bpf_capable())
+		return;
+
+	bpf_prog_ksym_set_addr(fp);
+	bpf_prog_ksym_set_name(fp);
+	fp->aux->ksym.prog = true;
+
+	bpf_ksym_add(&fp->aux->ksym);
+}
+
+void bpf_prog_kallsyms_del(struct bpf_prog *fp)
+{
+	if (!bpf_prog_kallsyms_candidate(fp))
+		return;
+
+	bpf_ksym_del(&fp->aux->ksym);
+}
+
+static struct bpf_ksym *bpf_ksym_find(unsigned long addr)
+{
+	struct latch_tree_node *n;
+
+	n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
+	return n ? container_of(n, struct bpf_ksym, tnode) : NULL;
+}
+
+const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
+				 unsigned long *off, char *sym)
+{
+	struct bpf_ksym *ksym;
+	char *ret = NULL;
+
+	rcu_read_lock();
+	ksym = bpf_ksym_find(addr);
+	if (ksym) {
+		unsigned long symbol_start = ksym->start;
+		unsigned long symbol_end = ksym->end;
+
+		strncpy(sym, ksym->name, KSYM_NAME_LEN);
+
+		ret = sym;
+		if (size)
+			*size = symbol_end - symbol_start;
+		if (off)
+			*off  = addr - symbol_start;
+	}
+	rcu_read_unlock();
+
+	return ret;
+}
+
+bool is_bpf_text_address(unsigned long addr)
+{
+	bool ret;
+
+	rcu_read_lock();
+	ret = bpf_ksym_find(addr) != NULL;
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr)
+{
+	struct bpf_ksym *ksym = bpf_ksym_find(addr);
+
+	return ksym && ksym->prog ?
+	       container_of(ksym, struct bpf_prog_aux, ksym)->prog :
+	       NULL;
+}
+
+const struct exception_table_entry *search_bpf_extables(unsigned long addr)
+{
+	const struct exception_table_entry *e = NULL;
+	struct bpf_prog *prog;
+
+	rcu_read_lock();
+	prog = bpf_prog_ksym_find(addr);
+	if (!prog)
+		goto out;
+	if (!prog->aux->num_exentries)
+		goto out;
+
+	e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr);
+out:
+	rcu_read_unlock();
+	return e;
+}
+
+int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
+		    char *sym)
+{
+	struct bpf_ksym *ksym;
+	unsigned int it = 0;
+	int ret = -ERANGE;
+
+	if (!bpf_jit_kallsyms_enabled())
+		return ret;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) {
+		if (it++ != symnum)
+			continue;
+
+		strncpy(sym, ksym->name, KSYM_NAME_LEN);
+
+		*value = ksym->start;
+		*type  = BPF_SYM_ELF_TYPE;
+
+		ret = 0;
+		break;
+	}
+	rcu_read_unlock();
+
+	return ret;
+}
+
+int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
+				struct bpf_jit_poke_descriptor *poke)
+{
+	struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
+	static const u32 poke_tab_max = 1024;
+	u32 slot = prog->aux->size_poke_tab;
+	u32 size = slot + 1;
+
+	if (size > poke_tab_max)
+		return -ENOSPC;
+	if (poke->tailcall_target || poke->tailcall_target_stable ||
+	    poke->tailcall_bypass || poke->adj_off || poke->bypass_addr)
+		return -EINVAL;
+
+	switch (poke->reason) {
+	case BPF_POKE_REASON_TAIL_CALL:
+		if (!poke->tail_call.map)
+			return -EINVAL;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL);
+	if (!tab)
+		return -ENOMEM;
+
+	memcpy(&tab[slot], poke, sizeof(*poke));
+	prog->aux->size_poke_tab = size;
+	prog->aux->poke_tab = tab;
+
+	return slot;
+}
+
+/*
+ * BPF program pack allocator.
+ *
+ * Most BPF programs are pretty small. Allocating a hole page for each
+ * program is sometime a waste. Many small bpf program also adds pressure
+ * to instruction TLB. To solve this issue, we introduce a BPF program pack
+ * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86)
+ * to host BPF programs.
+ */
+#define BPF_PROG_CHUNK_SHIFT	6
+#define BPF_PROG_CHUNK_SIZE	(1 << BPF_PROG_CHUNK_SHIFT)
+#define BPF_PROG_CHUNK_MASK	(~(BPF_PROG_CHUNK_SIZE - 1))
+
+struct bpf_prog_pack {
+	struct list_head list;
+	void *ptr;
+	unsigned long bitmap[];
+};
+
+void bpf_jit_fill_hole_with_zero(void *area, unsigned int size)
+{
+	memset(area, 0, size);
+}
+
+#define BPF_PROG_SIZE_TO_NBITS(size)	(round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE)
+
+static DEFINE_MUTEX(pack_mutex);
+static LIST_HEAD(pack_list);
+
+/* PMD_SIZE is not available in some special config, e.g. ARCH=arm with
+ * CONFIG_MMU=n. Use PAGE_SIZE in these cases.
+ */
+#ifdef PMD_SIZE
+#define BPF_PROG_PACK_SIZE (PMD_SIZE * num_possible_nodes())
+#else
+#define BPF_PROG_PACK_SIZE PAGE_SIZE
+#endif
+
+#define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE)
+
+static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns)
+{
+	struct bpf_prog_pack *pack;
+
+	pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)),
+		       GFP_KERNEL);
+	if (!pack)
+		return NULL;
+	pack->ptr = module_alloc(BPF_PROG_PACK_SIZE);
+	if (!pack->ptr) {
+		kfree(pack);
+		return NULL;
+	}
+	bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE);
+	bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE);
+	list_add_tail(&pack->list, &pack_list);
+
+	set_vm_flush_reset_perms(pack->ptr);
+	set_memory_ro((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE);
+	set_memory_x((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE);
+	return pack;
+}
+
+void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns)
+{
+	unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size);
+	struct bpf_prog_pack *pack;
+	unsigned long pos;
+	void *ptr = NULL;
+
+	mutex_lock(&pack_mutex);
+	if (size > BPF_PROG_PACK_SIZE) {
+		size = round_up(size, PAGE_SIZE);
+		ptr = module_alloc(size);
+		if (ptr) {
+			bpf_fill_ill_insns(ptr, size);
+			set_vm_flush_reset_perms(ptr);
+			set_memory_ro((unsigned long)ptr, size / PAGE_SIZE);
+			set_memory_x((unsigned long)ptr, size / PAGE_SIZE);
+		}
+		goto out;
+	}
+	list_for_each_entry(pack, &pack_list, list) {
+		pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
+						 nbits, 0);
+		if (pos < BPF_PROG_CHUNK_COUNT)
+			goto found_free_area;
+	}
+
+	pack = alloc_new_pack(bpf_fill_ill_insns);
+	if (!pack)
+		goto out;
+
+	pos = 0;
+
+found_free_area:
+	bitmap_set(pack->bitmap, pos, nbits);
+	ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT);
+
+out:
+	mutex_unlock(&pack_mutex);
+	return ptr;
+}
+
+void bpf_prog_pack_free(struct bpf_binary_header *hdr)
+{
+	struct bpf_prog_pack *pack = NULL, *tmp;
+	unsigned int nbits;
+	unsigned long pos;
+
+	mutex_lock(&pack_mutex);
+	if (hdr->size > BPF_PROG_PACK_SIZE) {
+		module_memfree(hdr);
+		goto out;
+	}
+
+	list_for_each_entry(tmp, &pack_list, list) {
+		if ((void *)hdr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > (void *)hdr) {
+			pack = tmp;
+			break;
+		}
+	}
+
+	if (WARN_ONCE(!pack, "bpf_prog_pack bug\n"))
+		goto out;
+
+	nbits = BPF_PROG_SIZE_TO_NBITS(hdr->size);
+	pos = ((unsigned long)hdr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT;
+
+	WARN_ONCE(bpf_arch_text_invalidate(hdr, hdr->size),
+		  "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n");
+
+	bitmap_clear(pack->bitmap, pos, nbits);
+	if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
+				       BPF_PROG_CHUNK_COUNT, 0) == 0) {
+		list_del(&pack->list);
+		module_memfree(pack->ptr);
+		kfree(pack);
+	}
+out:
+	mutex_unlock(&pack_mutex);
+}
+
+static atomic_long_t bpf_jit_current;
+
+/* Can be overridden by an arch's JIT compiler if it has a custom,
+ * dedicated BPF backend memory area, or if neither of the two
+ * below apply.
+ */
+u64 __weak bpf_jit_alloc_exec_limit(void)
+{
+#if defined(MODULES_VADDR)
+	return MODULES_END - MODULES_VADDR;
+#else
+	return VMALLOC_END - VMALLOC_START;
+#endif
+}
+
+static int __init bpf_jit_charge_init(void)
+{
+	/* Only used as heuristic here to derive limit. */
+	bpf_jit_limit_max = bpf_jit_alloc_exec_limit();
+	bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 1,
+					    PAGE_SIZE), LONG_MAX);
+	return 0;
+}
+pure_initcall(bpf_jit_charge_init);
+
+int bpf_jit_charge_modmem(u32 size)
+{
+	if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) {
+		if (!bpf_capable()) {
+			atomic_long_sub(size, &bpf_jit_current);
+			return -EPERM;
+		}
+	}
+
+	return 0;
+}
+
+void bpf_jit_uncharge_modmem(u32 size)
+{
+	atomic_long_sub(size, &bpf_jit_current);
+}
+
+void *__weak bpf_jit_alloc_exec(unsigned long size)
+{
+	return module_alloc(size);
+}
+
+void __weak bpf_jit_free_exec(void *addr)
+{
+	module_memfree(addr);
+}
+
+struct bpf_binary_header *
+bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
+		     unsigned int alignment,
+		     bpf_jit_fill_hole_t bpf_fill_ill_insns)
+{
+	struct bpf_binary_header *hdr;
+	u32 size, hole, start;
+
+	WARN_ON_ONCE(!is_power_of_2(alignment) ||
+		     alignment > BPF_IMAGE_ALIGNMENT);
+
+	/* Most of BPF filters are really small, but if some of them
+	 * fill a page, allow at least 128 extra bytes to insert a
+	 * random section of illegal instructions.
+	 */
+	size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
+
+	if (bpf_jit_charge_modmem(size))
+		return NULL;
+	hdr = bpf_jit_alloc_exec(size);
+	if (!hdr) {
+		bpf_jit_uncharge_modmem(size);
+		return NULL;
+	}
+
+	/* Fill space with illegal/arch-dep instructions. */
+	bpf_fill_ill_insns(hdr, size);
+
+	hdr->size = size;
+	hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
+		     PAGE_SIZE - sizeof(*hdr));
+	start = prandom_u32_max(hole) & ~(alignment - 1);
+
+	/* Leave a random number of instructions before BPF code. */
+	*image_ptr = &hdr->image[start];
+
+	return hdr;
+}
+
+void bpf_jit_binary_free(struct bpf_binary_header *hdr)
+{
+	u32 size = hdr->size;
+
+	bpf_jit_free_exec(hdr);
+	bpf_jit_uncharge_modmem(size);
+}
+
+/* Allocate jit binary from bpf_prog_pack allocator.
+ * Since the allocated memory is RO+X, the JIT engine cannot write directly
+ * to the memory. To solve this problem, a RW buffer is also allocated at
+ * as the same time. The JIT engine should calculate offsets based on the
+ * RO memory address, but write JITed program to the RW buffer. Once the
+ * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies
+ * the JITed program to the RO memory.
+ */
+struct bpf_binary_header *
+bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr,
+			  unsigned int alignment,
+			  struct bpf_binary_header **rw_header,
+			  u8 **rw_image,
+			  bpf_jit_fill_hole_t bpf_fill_ill_insns)
+{
+	struct bpf_binary_header *ro_header;
+	u32 size, hole, start;
+
+	WARN_ON_ONCE(!is_power_of_2(alignment) ||
+		     alignment > BPF_IMAGE_ALIGNMENT);
+
+	/* add 16 bytes for a random section of illegal instructions */
+	size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE);
+
+	if (bpf_jit_charge_modmem(size))
+		return NULL;
+	ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns);
+	if (!ro_header) {
+		bpf_jit_uncharge_modmem(size);
+		return NULL;
+	}
+
+	*rw_header = kvmalloc(size, GFP_KERNEL);
+	if (!*rw_header) {
+		bpf_arch_text_copy(&ro_header->size, &size, sizeof(size));
+		bpf_prog_pack_free(ro_header);
+		bpf_jit_uncharge_modmem(size);
+		return NULL;
+	}
+
+	/* Fill space with illegal/arch-dep instructions. */
+	bpf_fill_ill_insns(*rw_header, size);
+	(*rw_header)->size = size;
+
+	hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)),
+		     BPF_PROG_CHUNK_SIZE - sizeof(*ro_header));
+	start = prandom_u32_max(hole) & ~(alignment - 1);
+
+	*image_ptr = &ro_header->image[start];
+	*rw_image = &(*rw_header)->image[start];
+
+	return ro_header;
+}
+
+/* Copy JITed text from rw_header to its final location, the ro_header. */
+int bpf_jit_binary_pack_finalize(struct bpf_prog *prog,
+				 struct bpf_binary_header *ro_header,
+				 struct bpf_binary_header *rw_header)
+{
+	void *ptr;
+
+	ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size);
+
+	kvfree(rw_header);
+
+	if (IS_ERR(ptr)) {
+		bpf_prog_pack_free(ro_header);
+		return PTR_ERR(ptr);
+	}
+	return 0;
+}
+
+/* bpf_jit_binary_pack_free is called in two different scenarios:
+ *   1) when the program is freed after;
+ *   2) when the JIT engine fails (before bpf_jit_binary_pack_finalize).
+ * For case 2), we need to free both the RO memory and the RW buffer.
+ *
+ * bpf_jit_binary_pack_free requires proper ro_header->size. However,
+ * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size
+ * must be set with either bpf_jit_binary_pack_finalize (normal path) or
+ * bpf_arch_text_copy (when jit fails).
+ */
+void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header,
+			      struct bpf_binary_header *rw_header)
+{
+	u32 size = ro_header->size;
+
+	bpf_prog_pack_free(ro_header);
+	kvfree(rw_header);
+	bpf_jit_uncharge_modmem(size);
+}
+
+struct bpf_binary_header *
+bpf_jit_binary_pack_hdr(const struct bpf_prog *fp)
+{
+	unsigned long real_start = (unsigned long)fp->bpf_func;
+	unsigned long addr;
+
+	addr = real_start & BPF_PROG_CHUNK_MASK;
+	return (void *)addr;
+}
+
+static inline struct bpf_binary_header *
+bpf_jit_binary_hdr(const struct bpf_prog *fp)
+{
+	unsigned long real_start = (unsigned long)fp->bpf_func;
+	unsigned long addr;
+
+	addr = real_start & PAGE_MASK;
+	return (void *)addr;
+}
+
+/* This symbol is only overridden by archs that have different
+ * requirements than the usual eBPF JITs, f.e. when they only
+ * implement cBPF JIT, do not set images read-only, etc.
+ */
+void __weak bpf_jit_free(struct bpf_prog *fp)
+{
+	if (fp->jited) {
+		struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
+
+		bpf_jit_binary_free(hdr);
+		WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
+	}
+
+	bpf_prog_unlock_free(fp);
+}
+
+int bpf_jit_get_func_addr(const struct bpf_prog *prog,
+			  const struct bpf_insn *insn, bool extra_pass,
+			  u64 *func_addr, bool *func_addr_fixed)
+{
+	s16 off = insn->off;
+	s32 imm = insn->imm;
+	u8 *addr;
+
+	*func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL;
+	if (!*func_addr_fixed) {
+		/* Place-holder address till the last pass has collected
+		 * all addresses for JITed subprograms in which case we
+		 * can pick them up from prog->aux.
+		 */
+		if (!extra_pass)
+			addr = NULL;
+		else if (prog->aux->func &&
+			 off >= 0 && off < prog->aux->func_cnt)
+			addr = (u8 *)prog->aux->func[off]->bpf_func;
+		else
+			return -EINVAL;
+	} else {
+		/* Address of a BPF helper call. Since part of the core
+		 * kernel, it's always at a fixed location. __bpf_call_base
+		 * and the helper with imm relative to it are both in core
+		 * kernel.
+		 */
+		addr = (u8 *)__bpf_call_base + imm;
+	}
+
+	*func_addr = (unsigned long)addr;
+	return 0;
+}
+
+static int bpf_jit_blind_insn(const struct bpf_insn *from,
+			      const struct bpf_insn *aux,
+			      struct bpf_insn *to_buff,
+			      bool emit_zext)
+{
+	struct bpf_insn *to = to_buff;
+	u32 imm_rnd = get_random_u32();
+	s16 off;
+
+	BUILD_BUG_ON(BPF_REG_AX  + 1 != MAX_BPF_JIT_REG);
+	BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
+
+	/* Constraints on AX register:
+	 *
+	 * AX register is inaccessible from user space. It is mapped in
+	 * all JITs, and used here for constant blinding rewrites. It is
+	 * typically "stateless" meaning its contents are only valid within
+	 * the executed instruction, but not across several instructions.
+	 * There are a few exceptions however which are further detailed
+	 * below.
+	 *
+	 * Constant blinding is only used by JITs, not in the interpreter.
+	 * The interpreter uses AX in some occasions as a local temporary
+	 * register e.g. in DIV or MOD instructions.
+	 *
+	 * In restricted circumstances, the verifier can also use the AX
+	 * register for rewrites as long as they do not interfere with
+	 * the above cases!
+	 */
+	if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX)
+		goto out;
+
+	if (from->imm == 0 &&
+	    (from->code == (BPF_ALU   | BPF_MOV | BPF_K) ||
+	     from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
+		*to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
+		goto out;
+	}
+
+	switch (from->code) {
+	case BPF_ALU | BPF_ADD | BPF_K:
+	case BPF_ALU | BPF_SUB | BPF_K:
+	case BPF_ALU | BPF_AND | BPF_K:
+	case BPF_ALU | BPF_OR  | BPF_K:
+	case BPF_ALU | BPF_XOR | BPF_K:
+	case BPF_ALU | BPF_MUL | BPF_K:
+	case BPF_ALU | BPF_MOV | BPF_K:
+	case BPF_ALU | BPF_DIV | BPF_K:
+	case BPF_ALU | BPF_MOD | BPF_K:
+		*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
+		*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
+		*to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
+		break;
+
+	case BPF_ALU64 | BPF_ADD | BPF_K:
+	case BPF_ALU64 | BPF_SUB | BPF_K:
+	case BPF_ALU64 | BPF_AND | BPF_K:
+	case BPF_ALU64 | BPF_OR  | BPF_K:
+	case BPF_ALU64 | BPF_XOR | BPF_K:
+	case BPF_ALU64 | BPF_MUL | BPF_K:
+	case BPF_ALU64 | BPF_MOV | BPF_K:
+	case BPF_ALU64 | BPF_DIV | BPF_K:
+	case BPF_ALU64 | BPF_MOD | BPF_K:
+		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
+		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
+		*to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
+		break;
+
+	case BPF_JMP | BPF_JEQ  | BPF_K:
+	case BPF_JMP | BPF_JNE  | BPF_K:
+	case BPF_JMP | BPF_JGT  | BPF_K:
+	case BPF_JMP | BPF_JLT  | BPF_K:
+	case BPF_JMP | BPF_JGE  | BPF_K:
+	case BPF_JMP | BPF_JLE  | BPF_K:
+	case BPF_JMP | BPF_JSGT | BPF_K:
+	case BPF_JMP | BPF_JSLT | BPF_K:
+	case BPF_JMP | BPF_JSGE | BPF_K:
+	case BPF_JMP | BPF_JSLE | BPF_K:
+	case BPF_JMP | BPF_JSET | BPF_K:
+		/* Accommodate for extra offset in case of a backjump. */
+		off = from->off;
+		if (off < 0)
+			off -= 2;
+		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
+		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
+		*to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
+		break;
+
+	case BPF_JMP32 | BPF_JEQ  | BPF_K:
+	case BPF_JMP32 | BPF_JNE  | BPF_K:
+	case BPF_JMP32 | BPF_JGT  | BPF_K:
+	case BPF_JMP32 | BPF_JLT  | BPF_K:
+	case BPF_JMP32 | BPF_JGE  | BPF_K:
+	case BPF_JMP32 | BPF_JLE  | BPF_K:
+	case BPF_JMP32 | BPF_JSGT | BPF_K:
+	case BPF_JMP32 | BPF_JSLT | BPF_K:
+	case BPF_JMP32 | BPF_JSGE | BPF_K:
+	case BPF_JMP32 | BPF_JSLE | BPF_K:
+	case BPF_JMP32 | BPF_JSET | BPF_K:
+		/* Accommodate for extra offset in case of a backjump. */
+		off = from->off;
+		if (off < 0)
+			off -= 2;
+		*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
+		*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
+		*to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX,
+				      off);
+		break;
+
+	case BPF_LD | BPF_IMM | BPF_DW:
+		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
+		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
+		*to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
+		*to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
+		break;
+	case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
+		*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
+		*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
+		if (emit_zext)
+			*to++ = BPF_ZEXT_REG(BPF_REG_AX);
+		*to++ = BPF_ALU64_REG(BPF_OR,  aux[0].dst_reg, BPF_REG_AX);
+		break;
+
+	case BPF_ST | BPF_MEM | BPF_DW:
+	case BPF_ST | BPF_MEM | BPF_W:
+	case BPF_ST | BPF_MEM | BPF_H:
+	case BPF_ST | BPF_MEM | BPF_B:
+		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
+		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
+		*to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
+		break;
+	}
+out:
+	return to - to_buff;
+}
+
+static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
+					      gfp_t gfp_extra_flags)
+{
+	gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
+	struct bpf_prog *fp;
+
+	fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags);
+	if (fp != NULL) {
+		/* aux->prog still points to the fp_other one, so
+		 * when promoting the clone to the real program,
+		 * this still needs to be adapted.
+		 */
+		memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
+	}
+
+	return fp;
+}
+
+static void bpf_prog_clone_free(struct bpf_prog *fp)
+{
+	/* aux was stolen by the other clone, so we cannot free
+	 * it from this path! It will be freed eventually by the
+	 * other program on release.
+	 *
+	 * At this point, we don't need a deferred release since
+	 * clone is guaranteed to not be locked.
+	 */
+	fp->aux = NULL;
+	fp->stats = NULL;
+	fp->active = NULL;
+	__bpf_prog_free(fp);
+}
+
+void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
+{
+	/* We have to repoint aux->prog to self, as we don't
+	 * know whether fp here is the clone or the original.
+	 */
+	fp->aux->prog = fp;
+	bpf_prog_clone_free(fp_other);
+}
+
+struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
+{
+	struct bpf_insn insn_buff[16], aux[2];
+	struct bpf_prog *clone, *tmp;
+	int insn_delta, insn_cnt;
+	struct bpf_insn *insn;
+	int i, rewritten;
+
+	if (!prog->blinding_requested || prog->blinded)
+		return prog;
+
+	clone = bpf_prog_clone_create(prog, GFP_USER);
+	if (!clone)
+		return ERR_PTR(-ENOMEM);
+
+	insn_cnt = clone->len;
+	insn = clone->insnsi;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		if (bpf_pseudo_func(insn)) {
+			/* ld_imm64 with an address of bpf subprog is not
+			 * a user controlled constant. Don't randomize it,
+			 * since it will conflict with jit_subprogs() logic.
+			 */
+			insn++;
+			i++;
+			continue;
+		}
+
+		/* We temporarily need to hold the original ld64 insn
+		 * so that we can still access the first part in the
+		 * second blinding run.
+		 */
+		if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
+		    insn[1].code == 0)
+			memcpy(aux, insn, sizeof(aux));
+
+		rewritten = bpf_jit_blind_insn(insn, aux, insn_buff,
+						clone->aux->verifier_zext);
+		if (!rewritten)
+			continue;
+
+		tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
+		if (IS_ERR(tmp)) {
+			/* Patching may have repointed aux->prog during
+			 * realloc from the original one, so we need to
+			 * fix it up here on error.
+			 */
+			bpf_jit_prog_release_other(prog, clone);
+			return tmp;
+		}
+
+		clone = tmp;
+		insn_delta = rewritten - 1;
+
+		/* Walk new program and skip insns we just inserted. */
+		insn = clone->insnsi + i + insn_delta;
+		insn_cnt += insn_delta;
+		i        += insn_delta;
+	}
+
+	clone->blinded = 1;
+	return clone;
+}
+#endif /* CONFIG_BPF_JIT */
+
+/* Base function for offset calculation. Needs to go into .text section,
+ * therefore keeping it non-static as well; will also be used by JITs
+ * anyway later on, so do not let the compiler omit it. This also needs
+ * to go into kallsyms for correlation from e.g. bpftool, so naming
+ * must not change.
+ */
+noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__bpf_call_base);
+
+/* All UAPI available opcodes. */
+#define BPF_INSN_MAP(INSN_2, INSN_3)		\
+	/* 32 bit ALU operations. */		\
+	/*   Register based. */			\
+	INSN_3(ALU, ADD,  X),			\
+	INSN_3(ALU, SUB,  X),			\
+	INSN_3(ALU, AND,  X),			\
+	INSN_3(ALU, OR,   X),			\
+	INSN_3(ALU, LSH,  X),			\
+	INSN_3(ALU, RSH,  X),			\
+	INSN_3(ALU, XOR,  X),			\
+	INSN_3(ALU, MUL,  X),			\
+	INSN_3(ALU, MOV,  X),			\
+	INSN_3(ALU, ARSH, X),			\
+	INSN_3(ALU, DIV,  X),			\
+	INSN_3(ALU, MOD,  X),			\
+	INSN_2(ALU, NEG),			\
+	INSN_3(ALU, END, TO_BE),		\
+	INSN_3(ALU, END, TO_LE),		\
+	/*   Immediate based. */		\
+	INSN_3(ALU, ADD,  K),			\
+	INSN_3(ALU, SUB,  K),			\
+	INSN_3(ALU, AND,  K),			\
+	INSN_3(ALU, OR,   K),			\
+	INSN_3(ALU, LSH,  K),			\
+	INSN_3(ALU, RSH,  K),			\
+	INSN_3(ALU, XOR,  K),			\
+	INSN_3(ALU, MUL,  K),			\
+	INSN_3(ALU, MOV,  K),			\
+	INSN_3(ALU, ARSH, K),			\
+	INSN_3(ALU, DIV,  K),			\
+	INSN_3(ALU, MOD,  K),			\
+	/* 64 bit ALU operations. */		\
+	/*   Register based. */			\
+	INSN_3(ALU64, ADD,  X),			\
+	INSN_3(ALU64, SUB,  X),			\
+	INSN_3(ALU64, AND,  X),			\
+	INSN_3(ALU64, OR,   X),			\
+	INSN_3(ALU64, LSH,  X),			\
+	INSN_3(ALU64, RSH,  X),			\
+	INSN_3(ALU64, XOR,  X),			\
+	INSN_3(ALU64, MUL,  X),			\
+	INSN_3(ALU64, MOV,  X),			\
+	INSN_3(ALU64, ARSH, X),			\
+	INSN_3(ALU64, DIV,  X),			\
+	INSN_3(ALU64, MOD,  X),			\
+	INSN_2(ALU64, NEG),			\
+	/*   Immediate based. */		\
+	INSN_3(ALU64, ADD,  K),			\
+	INSN_3(ALU64, SUB,  K),			\
+	INSN_3(ALU64, AND,  K),			\
+	INSN_3(ALU64, OR,   K),			\
+	INSN_3(ALU64, LSH,  K),			\
+	INSN_3(ALU64, RSH,  K),			\
+	INSN_3(ALU64, XOR,  K),			\
+	INSN_3(ALU64, MUL,  K),			\
+	INSN_3(ALU64, MOV,  K),			\
+	INSN_3(ALU64, ARSH, K),			\
+	INSN_3(ALU64, DIV,  K),			\
+	INSN_3(ALU64, MOD,  K),			\
+	/* Call instruction. */			\
+	INSN_2(JMP, CALL),			\
+	/* Exit instruction. */			\
+	INSN_2(JMP, EXIT),			\
+	/* 32-bit Jump instructions. */		\
+	/*   Register based. */			\
+	INSN_3(JMP32, JEQ,  X),			\
+	INSN_3(JMP32, JNE,  X),			\
+	INSN_3(JMP32, JGT,  X),			\
+	INSN_3(JMP32, JLT,  X),			\
+	INSN_3(JMP32, JGE,  X),			\
+	INSN_3(JMP32, JLE,  X),			\
+	INSN_3(JMP32, JSGT, X),			\
+	INSN_3(JMP32, JSLT, X),			\
+	INSN_3(JMP32, JSGE, X),			\
+	INSN_3(JMP32, JSLE, X),			\
+	INSN_3(JMP32, JSET, X),			\
+	/*   Immediate based. */		\
+	INSN_3(JMP32, JEQ,  K),			\
+	INSN_3(JMP32, JNE,  K),			\
+	INSN_3(JMP32, JGT,  K),			\
+	INSN_3(JMP32, JLT,  K),			\
+	INSN_3(JMP32, JGE,  K),			\
+	INSN_3(JMP32, JLE,  K),			\
+	INSN_3(JMP32, JSGT, K),			\
+	INSN_3(JMP32, JSLT, K),			\
+	INSN_3(JMP32, JSGE, K),			\
+	INSN_3(JMP32, JSLE, K),			\
+	INSN_3(JMP32, JSET, K),			\
+	/* Jump instructions. */		\
+	/*   Register based. */			\
+	INSN_3(JMP, JEQ,  X),			\
+	INSN_3(JMP, JNE,  X),			\
+	INSN_3(JMP, JGT,  X),			\
+	INSN_3(JMP, JLT,  X),			\
+	INSN_3(JMP, JGE,  X),			\
+	INSN_3(JMP, JLE,  X),			\
+	INSN_3(JMP, JSGT, X),			\
+	INSN_3(JMP, JSLT, X),			\
+	INSN_3(JMP, JSGE, X),			\
+	INSN_3(JMP, JSLE, X),			\
+	INSN_3(JMP, JSET, X),			\
+	/*   Immediate based. */		\
+	INSN_3(JMP, JEQ,  K),			\
+	INSN_3(JMP, JNE,  K),			\
+	INSN_3(JMP, JGT,  K),			\
+	INSN_3(JMP, JLT,  K),			\
+	INSN_3(JMP, JGE,  K),			\
+	INSN_3(JMP, JLE,  K),			\
+	INSN_3(JMP, JSGT, K),			\
+	INSN_3(JMP, JSLT, K),			\
+	INSN_3(JMP, JSGE, K),			\
+	INSN_3(JMP, JSLE, K),			\
+	INSN_3(JMP, JSET, K),			\
+	INSN_2(JMP, JA),			\
+	INSN_2(JMP32, JA),			\
+	/* Store instructions. */		\
+	/*   Register based. */			\
+	INSN_3(STX, MEM,  B),			\
+	INSN_3(STX, MEM,  H),			\
+	INSN_3(STX, MEM,  W),			\
+	INSN_3(STX, MEM,  DW),			\
+	INSN_3(STX, ATOMIC, W),			\
+	INSN_3(STX, ATOMIC, DW),		\
+	/*   Immediate based. */		\
+	INSN_3(ST, MEM, B),			\
+	INSN_3(ST, MEM, H),			\
+	INSN_3(ST, MEM, W),			\
+	INSN_3(ST, MEM, DW),			\
+	/* Load instructions. */		\
+	/*   Register based. */			\
+	INSN_3(LDX, MEM, B),			\
+	INSN_3(LDX, MEM, H),			\
+	INSN_3(LDX, MEM, W),			\
+	INSN_3(LDX, MEM, DW),			\
+	/*   Immediate based. */		\
+	INSN_3(LD, IMM, DW)
+
+bool bpf_opcode_in_insntable(u8 code)
+{
+#define BPF_INSN_2_TBL(x, y)    [BPF_##x | BPF_##y] = true
+#define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
+	static const bool public_insntable[256] = {
+		[0 ... 255] = false,
+		/* Now overwrite non-defaults ... */
+		BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
+		/* UAPI exposed, but rewritten opcodes. cBPF carry-over. */
+		[BPF_LD | BPF_ABS | BPF_B] = true,
+		[BPF_LD | BPF_ABS | BPF_H] = true,
+		[BPF_LD | BPF_ABS | BPF_W] = true,
+		[BPF_LD | BPF_IND | BPF_B] = true,
+		[BPF_LD | BPF_IND | BPF_H] = true,
+		[BPF_LD | BPF_IND | BPF_W] = true,
+	};
+#undef BPF_INSN_3_TBL
+#undef BPF_INSN_2_TBL
+	return public_insntable[code];
+}
+
+#ifndef CONFIG_BPF_JIT_ALWAYS_ON
+u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
+{
+	memset(dst, 0, size);
+	return -EFAULT;
+}
+
+/**
+ *	___bpf_prog_run - run eBPF program on a given context
+ *	@regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
+ *	@insn: is the array of eBPF instructions
+ *
+ * Decode and execute eBPF instructions.
+ *
+ * Return: whatever value is in %BPF_R0 at program exit
+ */
+static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn)
+{
+#define BPF_INSN_2_LBL(x, y)    [BPF_##x | BPF_##y] = &&x##_##y
+#define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
+	static const void * const jumptable[256] __annotate_jump_table = {
+		[0 ... 255] = &&default_label,
+		/* Now overwrite non-defaults ... */
+		BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
+		/* Non-UAPI available opcodes. */
+		[BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,
+		[BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
+		[BPF_ST  | BPF_NOSPEC] = &&ST_NOSPEC,
+		[BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B,
+		[BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H,
+		[BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W,
+		[BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW,
+	};
+#undef BPF_INSN_3_LBL
+#undef BPF_INSN_2_LBL
+	u32 tail_call_cnt = 0;
+
+#define CONT	 ({ insn++; goto select_insn; })
+#define CONT_JMP ({ insn++; goto select_insn; })
+
+select_insn:
+	goto *jumptable[insn->code];
+
+	/* Explicitly mask the register-based shift amounts with 63 or 31
+	 * to avoid undefined behavior. Normally this won't affect the
+	 * generated code, for example, in case of native 64 bit archs such
+	 * as x86-64 or arm64, the compiler is optimizing the AND away for
+	 * the interpreter. In case of JITs, each of the JIT backends compiles
+	 * the BPF shift operations to machine instructions which produce
+	 * implementation-defined results in such a case; the resulting
+	 * contents of the register may be arbitrary, but program behaviour
+	 * as a whole remains defined. In other words, in case of JIT backends,
+	 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation.
+	 */
+	/* ALU (shifts) */
+#define SHT(OPCODE, OP)					\
+	ALU64_##OPCODE##_X:				\
+		DST = DST OP (SRC & 63);		\
+		CONT;					\
+	ALU_##OPCODE##_X:				\
+		DST = (u32) DST OP ((u32) SRC & 31);	\
+		CONT;					\
+	ALU64_##OPCODE##_K:				\
+		DST = DST OP IMM;			\
+		CONT;					\
+	ALU_##OPCODE##_K:				\
+		DST = (u32) DST OP (u32) IMM;		\
+		CONT;
+	/* ALU (rest) */
+#define ALU(OPCODE, OP)					\
+	ALU64_##OPCODE##_X:				\
+		DST = DST OP SRC;			\
+		CONT;					\
+	ALU_##OPCODE##_X:				\
+		DST = (u32) DST OP (u32) SRC;		\
+		CONT;					\
+	ALU64_##OPCODE##_K:				\
+		DST = DST OP IMM;			\
+		CONT;					\
+	ALU_##OPCODE##_K:				\
+		DST = (u32) DST OP (u32) IMM;		\
+		CONT;
+	ALU(ADD,  +)
+	ALU(SUB,  -)
+	ALU(AND,  &)
+	ALU(OR,   |)
+	ALU(XOR,  ^)
+	ALU(MUL,  *)
+	SHT(LSH, <<)
+	SHT(RSH, >>)
+#undef SHT
+#undef ALU
+	ALU_NEG:
+		DST = (u32) -DST;
+		CONT;
+	ALU64_NEG:
+		DST = -DST;
+		CONT;
+	ALU_MOV_X:
+		DST = (u32) SRC;
+		CONT;
+	ALU_MOV_K:
+		DST = (u32) IMM;
+		CONT;
+	ALU64_MOV_X:
+		DST = SRC;
+		CONT;
+	ALU64_MOV_K:
+		DST = IMM;
+		CONT;
+	LD_IMM_DW:
+		DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
+		insn++;
+		CONT;
+	ALU_ARSH_X:
+		DST = (u64) (u32) (((s32) DST) >> (SRC & 31));
+		CONT;
+	ALU_ARSH_K:
+		DST = (u64) (u32) (((s32) DST) >> IMM);
+		CONT;
+	ALU64_ARSH_X:
+		(*(s64 *) &DST) >>= (SRC & 63);
+		CONT;
+	ALU64_ARSH_K:
+		(*(s64 *) &DST) >>= IMM;
+		CONT;
+	ALU64_MOD_X:
+		div64_u64_rem(DST, SRC, &AX);
+		DST = AX;
+		CONT;
+	ALU_MOD_X:
+		AX = (u32) DST;
+		DST = do_div(AX, (u32) SRC);
+		CONT;
+	ALU64_MOD_K:
+		div64_u64_rem(DST, IMM, &AX);
+		DST = AX;
+		CONT;
+	ALU_MOD_K:
+		AX = (u32) DST;
+		DST = do_div(AX, (u32) IMM);
+		CONT;
+	ALU64_DIV_X:
+		DST = div64_u64(DST, SRC);
+		CONT;
+	ALU_DIV_X:
+		AX = (u32) DST;
+		do_div(AX, (u32) SRC);
+		DST = (u32) AX;
+		CONT;
+	ALU64_DIV_K:
+		DST = div64_u64(DST, IMM);
+		CONT;
+	ALU_DIV_K:
+		AX = (u32) DST;
+		do_div(AX, (u32) IMM);
+		DST = (u32) AX;
+		CONT;
+	ALU_END_TO_BE:
+		switch (IMM) {
+		case 16:
+			DST = (__force u16) cpu_to_be16(DST);
+			break;
+		case 32:
+			DST = (__force u32) cpu_to_be32(DST);
+			break;
+		case 64:
+			DST = (__force u64) cpu_to_be64(DST);
+			break;
+		}
+		CONT;
+	ALU_END_TO_LE:
+		switch (IMM) {
+		case 16:
+			DST = (__force u16) cpu_to_le16(DST);
+			break;
+		case 32:
+			DST = (__force u32) cpu_to_le32(DST);
+			break;
+		case 64:
+			DST = (__force u64) cpu_to_le64(DST);
+			break;
+		}
+		CONT;
+
+	/* CALL */
+	JMP_CALL:
+		/* Function call scratches BPF_R1-BPF_R5 registers,
+		 * preserves BPF_R6-BPF_R9, and stores return value
+		 * into BPF_R0.
+		 */
+		BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
+						       BPF_R4, BPF_R5);
+		CONT;
+
+	JMP_CALL_ARGS:
+		BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
+							    BPF_R3, BPF_R4,
+							    BPF_R5,
+							    insn + insn->off + 1);
+		CONT;
+
+	JMP_TAIL_CALL: {
+		struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
+		struct bpf_array *array = container_of(map, struct bpf_array, map);
+		struct bpf_prog *prog;
+		u32 index = BPF_R3;
+
+		if (unlikely(index >= array->map.max_entries))
+			goto out;
+
+		if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT))
+			goto out;
+
+		tail_call_cnt++;
+
+		prog = READ_ONCE(array->ptrs[index]);
+		if (!prog)
+			goto out;
+
+		/* ARG1 at this point is guaranteed to point to CTX from
+		 * the verifier side due to the fact that the tail call is
+		 * handled like a helper, that is, bpf_tail_call_proto,
+		 * where arg1_type is ARG_PTR_TO_CTX.
+		 */
+		insn = prog->insnsi;
+		goto select_insn;
+out:
+		CONT;
+	}
+	JMP_JA:
+		insn += insn->off;
+		CONT;
+	JMP32_JA:
+		insn += insn->imm;
+		CONT;
+	JMP_EXIT:
+		return BPF_R0;
+	/* JMP */
+#define COND_JMP(SIGN, OPCODE, CMP_OP)				\
+	JMP_##OPCODE##_X:					\
+		if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) {	\
+			insn += insn->off;			\
+			CONT_JMP;				\
+		}						\
+		CONT;						\
+	JMP32_##OPCODE##_X:					\
+		if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) {	\
+			insn += insn->off;			\
+			CONT_JMP;				\
+		}						\
+		CONT;						\
+	JMP_##OPCODE##_K:					\
+		if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) {	\
+			insn += insn->off;			\
+			CONT_JMP;				\
+		}						\
+		CONT;						\
+	JMP32_##OPCODE##_K:					\
+		if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) {	\
+			insn += insn->off;			\
+			CONT_JMP;				\
+		}						\
+		CONT;
+	COND_JMP(u, JEQ, ==)
+	COND_JMP(u, JNE, !=)
+	COND_JMP(u, JGT, >)
+	COND_JMP(u, JLT, <)
+	COND_JMP(u, JGE, >=)
+	COND_JMP(u, JLE, <=)
+	COND_JMP(u, JSET, &)
+	COND_JMP(s, JSGT, >)
+	COND_JMP(s, JSLT, <)
+	COND_JMP(s, JSGE, >=)
+	COND_JMP(s, JSLE, <=)
+#undef COND_JMP
+	/* ST, STX and LDX*/
+	ST_NOSPEC:
+		/* Speculation barrier for mitigating Speculative Store Bypass.
+		 * In case of arm64, we rely on the firmware mitigation as
+		 * controlled via the ssbd kernel parameter. Whenever the
+		 * mitigation is enabled, it works for all of the kernel code
+		 * with no need to provide any additional instructions here.
+		 * In case of x86, we use 'lfence' insn for mitigation. We
+		 * reuse preexisting logic from Spectre v1 mitigation that
+		 * happens to produce the required code on x86 for v4 as well.
+		 */
+		barrier_nospec();
+		CONT;
+#define LDST(SIZEOP, SIZE)						\
+	STX_MEM_##SIZEOP:						\
+		*(SIZE *)(unsigned long) (DST + insn->off) = SRC;	\
+		CONT;							\
+	ST_MEM_##SIZEOP:						\
+		*(SIZE *)(unsigned long) (DST + insn->off) = IMM;	\
+		CONT;							\
+	LDX_MEM_##SIZEOP:						\
+		DST = *(SIZE *)(unsigned long) (SRC + insn->off);	\
+		CONT;							\
+	LDX_PROBE_MEM_##SIZEOP:						\
+		bpf_probe_read_kernel(&DST, sizeof(SIZE),		\
+				      (const void *)(long) (SRC + insn->off));	\
+		DST = *((SIZE *)&DST);					\
+		CONT;
+
+	LDST(B,   u8)
+	LDST(H,  u16)
+	LDST(W,  u32)
+	LDST(DW, u64)
+#undef LDST
+
+#define ATOMIC_ALU_OP(BOP, KOP)						\
+		case BOP:						\
+			if (BPF_SIZE(insn->code) == BPF_W)		\
+				atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \
+					     (DST + insn->off));	\
+			else						\
+				atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \
+					       (DST + insn->off));	\
+			break;						\
+		case BOP | BPF_FETCH:					\
+			if (BPF_SIZE(insn->code) == BPF_W)		\
+				SRC = (u32) atomic_fetch_##KOP(		\
+					(u32) SRC,			\
+					(atomic_t *)(unsigned long) (DST + insn->off)); \
+			else						\
+				SRC = (u64) atomic64_fetch_##KOP(	\
+					(u64) SRC,			\
+					(atomic64_t *)(unsigned long) (DST + insn->off)); \
+			break;
+
+	STX_ATOMIC_DW:
+	STX_ATOMIC_W:
+		switch (IMM) {
+		ATOMIC_ALU_OP(BPF_ADD, add)
+		ATOMIC_ALU_OP(BPF_AND, and)
+		ATOMIC_ALU_OP(BPF_OR, or)
+		ATOMIC_ALU_OP(BPF_XOR, xor)
+#undef ATOMIC_ALU_OP
+
+		case BPF_XCHG:
+			if (BPF_SIZE(insn->code) == BPF_W)
+				SRC = (u32) atomic_xchg(
+					(atomic_t *)(unsigned long) (DST + insn->off),
+					(u32) SRC);
+			else
+				SRC = (u64) atomic64_xchg(
+					(atomic64_t *)(unsigned long) (DST + insn->off),
+					(u64) SRC);
+			break;
+		case BPF_CMPXCHG:
+			if (BPF_SIZE(insn->code) == BPF_W)
+				BPF_R0 = (u32) atomic_cmpxchg(
+					(atomic_t *)(unsigned long) (DST + insn->off),
+					(u32) BPF_R0, (u32) SRC);
+			else
+				BPF_R0 = (u64) atomic64_cmpxchg(
+					(atomic64_t *)(unsigned long) (DST + insn->off),
+					(u64) BPF_R0, (u64) SRC);
+			break;
+
+		default:
+			goto default_label;
+		}
+		CONT;
+
+	default_label:
+		/* If we ever reach this, we have a bug somewhere. Die hard here
+		 * instead of just returning 0; we could be somewhere in a subprog,
+		 * so execution could continue otherwise which we do /not/ want.
+		 *
+		 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable().
+		 */
+		pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n",
+			insn->code, insn->imm);
+		BUG_ON(1);
+		return 0;
+}
+
+#define PROG_NAME(stack_size) __bpf_prog_run##stack_size
+#define DEFINE_BPF_PROG_RUN(stack_size) \
+static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
+{ \
+	u64 stack[stack_size / sizeof(u64)]; \
+	u64 regs[MAX_BPF_EXT_REG] = {}; \
+\
+	FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
+	ARG1 = (u64) (unsigned long) ctx; \
+	return ___bpf_prog_run(regs, insn); \
+}
+
+#define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size
+#define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \
+static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \
+				      const struct bpf_insn *insn) \
+{ \
+	u64 stack[stack_size / sizeof(u64)]; \
+	u64 regs[MAX_BPF_EXT_REG]; \
+\
+	FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
+	BPF_R1 = r1; \
+	BPF_R2 = r2; \
+	BPF_R3 = r3; \
+	BPF_R4 = r4; \
+	BPF_R5 = r5; \
+	return ___bpf_prog_run(regs, insn); \
+}
+
+#define EVAL1(FN, X) FN(X)
+#define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
+#define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
+#define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
+#define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
+#define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
+
+EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
+EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
+EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
+
+EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192);
+EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384);
+EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512);
+
+#define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
+
+static unsigned int (*interpreters[])(const void *ctx,
+				      const struct bpf_insn *insn) = {
+EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
+EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
+EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
+};
+#undef PROG_NAME_LIST
+#define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
+static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
+				  const struct bpf_insn *insn) = {
+EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
+EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
+EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
+};
+#undef PROG_NAME_LIST
+
+void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
+{
+	stack_depth = max_t(u32, stack_depth, 1);
+	insn->off = (s16) insn->imm;
+	insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] -
+		__bpf_call_base_args;
+	insn->code = BPF_JMP | BPF_CALL_ARGS;
+}
+
+#else
+static unsigned int __bpf_prog_ret0_warn(const void *ctx,
+					 const struct bpf_insn *insn)
+{
+	/* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON
+	 * is not working properly, so warn about it!
+	 */
+	WARN_ON_ONCE(1);
+	return 0;
+}
+#endif
+
+bool bpf_prog_map_compatible(struct bpf_map *map,
+			     const struct bpf_prog *fp)
+{
+	enum bpf_prog_type prog_type = resolve_prog_type(fp);
+	bool ret;
+
+	if (fp->kprobe_override)
+		return false;
+
+	spin_lock(&map->owner.lock);
+	if (!map->owner.type) {
+		/* There's no owner yet where we could check for
+		 * compatibility.
+		 */
+		map->owner.type  = prog_type;
+		map->owner.jited = fp->jited;
+		map->owner.xdp_has_frags = fp->aux->xdp_has_frags;
+		ret = true;
+	} else {
+		ret = map->owner.type  == prog_type &&
+		      map->owner.jited == fp->jited &&
+		      map->owner.xdp_has_frags == fp->aux->xdp_has_frags;
+	}
+	spin_unlock(&map->owner.lock);
+
+	return ret;
+}
+
+static int bpf_check_tail_call(const struct bpf_prog *fp)
+{
+	struct bpf_prog_aux *aux = fp->aux;
+	int i, ret = 0;
+
+	mutex_lock(&aux->used_maps_mutex);
+	for (i = 0; i < aux->used_map_cnt; i++) {
+		struct bpf_map *map = aux->used_maps[i];
+
+		if (!map_type_contains_progs(map))
+			continue;
+
+		if (!bpf_prog_map_compatible(map, fp)) {
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
+out:
+	mutex_unlock(&aux->used_maps_mutex);
+	return ret;
+}
+
+static void bpf_prog_select_func(struct bpf_prog *fp)
+{
+#ifndef CONFIG_BPF_JIT_ALWAYS_ON
+	u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
+
+	fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
+#else
+	fp->bpf_func = __bpf_prog_ret0_warn;
+#endif
+}
+
+/**
+ *	bpf_prog_select_runtime - select exec runtime for BPF program
+ *	@fp: bpf_prog populated with BPF program
+ *	@err: pointer to error variable
+ *
+ * Try to JIT eBPF program, if JIT is not available, use interpreter.
+ * The BPF program will be executed via bpf_prog_run() function.
+ *
+ * Return: the &fp argument along with &err set to 0 for success or
+ * a negative errno code on failure
+ */
+struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
+{
+	/* In case of BPF to BPF calls, verifier did all the prep
+	 * work with regards to JITing, etc.
+	 */
+	bool jit_needed = false;
+
+	if (fp->bpf_func)
+		goto finalize;
+
+	if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) ||
+	    bpf_prog_has_kfunc_call(fp))
+		jit_needed = true;
+
+	bpf_prog_select_func(fp);
+
+	/* eBPF JITs can rewrite the program in case constant
+	 * blinding is active. However, in case of error during
+	 * blinding, bpf_int_jit_compile() must always return a
+	 * valid program, which in this case would simply not
+	 * be JITed, but falls back to the interpreter.
+	 */
+	if (!bpf_prog_is_dev_bound(fp->aux)) {
+		*err = bpf_prog_alloc_jited_linfo(fp);
+		if (*err)
+			return fp;
+
+		fp = bpf_int_jit_compile(fp);
+		bpf_prog_jit_attempt_done(fp);
+		if (!fp->jited && jit_needed) {
+			*err = -ENOTSUPP;
+			return fp;
+		}
+	} else {
+		*err = bpf_prog_offload_compile(fp);
+		if (*err)
+			return fp;
+	}
+
+finalize:
+	bpf_prog_lock_ro(fp);
+
+	/* The tail call compatibility check can only be done at
+	 * this late stage as we need to determine, if we deal
+	 * with JITed or non JITed program concatenations and not
+	 * all eBPF JITs might immediately support all features.
+	 */
+	*err = bpf_check_tail_call(fp);
+
+	return fp;
+}
+EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
+
+static unsigned int __bpf_prog_ret1(const void *ctx,
+				    const struct bpf_insn *insn)
+{
+	return 1;
+}
+
+static struct bpf_prog_dummy {
+	struct bpf_prog prog;
+} dummy_bpf_prog = {
+	.prog = {
+		.bpf_func = __bpf_prog_ret1,
+	},
+};
+
+struct bpf_empty_prog_array bpf_empty_prog_array = {
+	.null_prog = NULL,
+};
+EXPORT_SYMBOL(bpf_empty_prog_array);
+
+struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
+{
+	if (prog_cnt)
+		return kzalloc(sizeof(struct bpf_prog_array) +
+			       sizeof(struct bpf_prog_array_item) *
+			       (prog_cnt + 1),
+			       flags);
+
+	return &bpf_empty_prog_array.hdr;
+}
+
+void bpf_prog_array_free(struct bpf_prog_array *progs)
+{
+	if (!progs || progs == &bpf_empty_prog_array.hdr)
+		return;
+	kfree_rcu(progs, rcu);
+}
+
+static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu)
+{
+	struct bpf_prog_array *progs;
+
+	progs = container_of(rcu, struct bpf_prog_array, rcu);
+	kfree_rcu(progs, rcu);
+}
+
+void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs)
+{
+	if (!progs || progs == &bpf_empty_prog_array.hdr)
+		return;
+	call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb);
+}
+
+int bpf_prog_array_length(struct bpf_prog_array *array)
+{
+	struct bpf_prog_array_item *item;
+	u32 cnt = 0;
+
+	for (item = array->items; item->prog; item++)
+		if (item->prog != &dummy_bpf_prog.prog)
+			cnt++;
+	return cnt;
+}
+
+bool bpf_prog_array_is_empty(struct bpf_prog_array *array)
+{
+	struct bpf_prog_array_item *item;
+
+	for (item = array->items; item->prog; item++)
+		if (item->prog != &dummy_bpf_prog.prog)
+			return false;
+	return true;
+}
+
+static bool bpf_prog_array_copy_core(struct bpf_prog_array *array,
+				     u32 *prog_ids,
+				     u32 request_cnt)
+{
+	struct bpf_prog_array_item *item;
+	int i = 0;
+
+	for (item = array->items; item->prog; item++) {
+		if (item->prog == &dummy_bpf_prog.prog)
+			continue;
+		prog_ids[i] = item->prog->aux->id;
+		if (++i == request_cnt) {
+			item++;
+			break;
+		}
+	}
+
+	return !!(item->prog);
+}
+
+int bpf_prog_array_copy_to_user(struct bpf_prog_array *array,
+				__u32 __user *prog_ids, u32 cnt)
+{
+	unsigned long err = 0;
+	bool nospc;
+	u32 *ids;
+
+	/* users of this function are doing:
+	 * cnt = bpf_prog_array_length();
+	 * if (cnt > 0)
+	 *     bpf_prog_array_copy_to_user(..., cnt);
+	 * so below kcalloc doesn't need extra cnt > 0 check.
+	 */
+	ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);
+	if (!ids)
+		return -ENOMEM;
+	nospc = bpf_prog_array_copy_core(array, ids, cnt);
+	err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
+	kfree(ids);
+	if (err)
+		return -EFAULT;
+	if (nospc)
+		return -ENOSPC;
+	return 0;
+}
+
+void bpf_prog_array_delete_safe(struct bpf_prog_array *array,
+				struct bpf_prog *old_prog)
+{
+	struct bpf_prog_array_item *item;
+
+	for (item = array->items; item->prog; item++)
+		if (item->prog == old_prog) {
+			WRITE_ONCE(item->prog, &dummy_bpf_prog.prog);
+			break;
+		}
+}
+
+/**
+ * bpf_prog_array_delete_safe_at() - Replaces the program at the given
+ *                                   index into the program array with
+ *                                   a dummy no-op program.
+ * @array: a bpf_prog_array
+ * @index: the index of the program to replace
+ *
+ * Skips over dummy programs, by not counting them, when calculating
+ * the position of the program to replace.
+ *
+ * Return:
+ * * 0		- Success
+ * * -EINVAL	- Invalid index value. Must be a non-negative integer.
+ * * -ENOENT	- Index out of range
+ */
+int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index)
+{
+	return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog);
+}
+
+/**
+ * bpf_prog_array_update_at() - Updates the program at the given index
+ *                              into the program array.
+ * @array: a bpf_prog_array
+ * @index: the index of the program to update
+ * @prog: the program to insert into the array
+ *
+ * Skips over dummy programs, by not counting them, when calculating
+ * the position of the program to update.
+ *
+ * Return:
+ * * 0		- Success
+ * * -EINVAL	- Invalid index value. Must be a non-negative integer.
+ * * -ENOENT	- Index out of range
+ */
+int bpf_prog_array_update_at(struct bpf_prog_array *array, int index,
+			     struct bpf_prog *prog)
+{
+	struct bpf_prog_array_item *item;
+
+	if (unlikely(index < 0))
+		return -EINVAL;
+
+	for (item = array->items; item->prog; item++) {
+		if (item->prog == &dummy_bpf_prog.prog)
+			continue;
+		if (!index) {
+			WRITE_ONCE(item->prog, prog);
+			return 0;
+		}
+		index--;
+	}
+	return -ENOENT;
+}
+
+int bpf_prog_array_copy(struct bpf_prog_array *old_array,
+			struct bpf_prog *exclude_prog,
+			struct bpf_prog *include_prog,
+			u64 bpf_cookie,
+			struct bpf_prog_array **new_array)
+{
+	int new_prog_cnt, carry_prog_cnt = 0;
+	struct bpf_prog_array_item *existing, *new;
+	struct bpf_prog_array *array;
+	bool found_exclude = false;
+
+	/* Figure out how many existing progs we need to carry over to
+	 * the new array.
+	 */
+	if (old_array) {
+		existing = old_array->items;
+		for (; existing->prog; existing++) {
+			if (existing->prog == exclude_prog) {
+				found_exclude = true;
+				continue;
+			}
+			if (existing->prog != &dummy_bpf_prog.prog)
+				carry_prog_cnt++;
+			if (existing->prog == include_prog)
+				return -EEXIST;
+		}
+	}
+
+	if (exclude_prog && !found_exclude)
+		return -ENOENT;
+
+	/* How many progs (not NULL) will be in the new array? */
+	new_prog_cnt = carry_prog_cnt;
+	if (include_prog)
+		new_prog_cnt += 1;
+
+	/* Do we have any prog (not NULL) in the new array? */
+	if (!new_prog_cnt) {
+		*new_array = NULL;
+		return 0;
+	}
+
+	/* +1 as the end of prog_array is marked with NULL */
+	array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);
+	if (!array)
+		return -ENOMEM;
+	new = array->items;
+
+	/* Fill in the new prog array */
+	if (carry_prog_cnt) {
+		existing = old_array->items;
+		for (; existing->prog; existing++) {
+			if (existing->prog == exclude_prog ||
+			    existing->prog == &dummy_bpf_prog.prog)
+				continue;
+
+			new->prog = existing->prog;
+			new->bpf_cookie = existing->bpf_cookie;
+			new++;
+		}
+	}
+	if (include_prog) {
+		new->prog = include_prog;
+		new->bpf_cookie = bpf_cookie;
+		new++;
+	}
+	new->prog = NULL;
+	*new_array = array;
+	return 0;
+}
+
+int bpf_prog_array_copy_info(struct bpf_prog_array *array,
+			     u32 *prog_ids, u32 request_cnt,
+			     u32 *prog_cnt)
+{
+	u32 cnt = 0;
+
+	if (array)
+		cnt = bpf_prog_array_length(array);
+
+	*prog_cnt = cnt;
+
+	/* return early if user requested only program count or nothing to copy */
+	if (!request_cnt || !cnt)
+		return 0;
+
+	/* this function is called under trace/bpf_trace.c: bpf_event_mutex */
+	return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC
+								     : 0;
+}
+
+void __bpf_free_used_maps(struct bpf_prog_aux *aux,
+			  struct bpf_map **used_maps, u32 len)
+{
+	struct bpf_map *map;
+	u32 i;
+
+	for (i = 0; i < len; i++) {
+		map = used_maps[i];
+		if (map->ops->map_poke_untrack)
+			map->ops->map_poke_untrack(map, aux);
+		bpf_map_put(map);
+	}
+}
+
+static void bpf_free_used_maps(struct bpf_prog_aux *aux)
+{
+	__bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt);
+	kfree(aux->used_maps);
+}
+
+void __bpf_free_used_btfs(struct bpf_prog_aux *aux,
+			  struct btf_mod_pair *used_btfs, u32 len)
+{
+#ifdef CONFIG_BPF_SYSCALL
+	struct btf_mod_pair *btf_mod;
+	u32 i;
+
+	for (i = 0; i < len; i++) {
+		btf_mod = &used_btfs[i];
+		if (btf_mod->module)
+			module_put(btf_mod->module);
+		btf_put(btf_mod->btf);
+	}
+#endif
+}
+
+static void bpf_free_used_btfs(struct bpf_prog_aux *aux)
+{
+	__bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt);
+	kfree(aux->used_btfs);
+}
+
+static void bpf_prog_free_deferred(struct work_struct *work)
+{
+	struct bpf_prog_aux *aux;
+	int i;
+
+	aux = container_of(work, struct bpf_prog_aux, work);
+#ifdef CONFIG_BPF_SYSCALL
+	bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab);
+#endif
+#ifdef CONFIG_CGROUP_BPF
+	if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID)
+		bpf_cgroup_atype_put(aux->cgroup_atype);
+#endif
+	bpf_free_used_maps(aux);
+	bpf_free_used_btfs(aux);
+	if (bpf_prog_is_dev_bound(aux))
+		bpf_prog_offload_destroy(aux->prog);
+#ifdef CONFIG_PERF_EVENTS
+	if (aux->prog->has_callchain_buf)
+		put_callchain_buffers();
+#endif
+	if (aux->dst_trampoline)
+		bpf_trampoline_put(aux->dst_trampoline);
+	for (i = 0; i < aux->func_cnt; i++) {
+		/* We can just unlink the subprog poke descriptor table as
+		 * it was originally linked to the main program and is also
+		 * released along with it.
+		 */
+		aux->func[i]->aux->poke_tab = NULL;
+		bpf_jit_free(aux->func[i]);
+	}
+	if (aux->func_cnt) {
+		kfree(aux->func);
+		bpf_prog_unlock_free(aux->prog);
+	} else {
+		bpf_jit_free(aux->prog);
+	}
+}
+
+void bpf_prog_free(struct bpf_prog *fp)
+{
+	struct bpf_prog_aux *aux = fp->aux;
+
+	if (aux->dst_prog)
+		bpf_prog_put(aux->dst_prog);
+	INIT_WORK(&aux->work, bpf_prog_free_deferred);
+	schedule_work(&aux->work);
+}
+EXPORT_SYMBOL_GPL(bpf_prog_free);
+
+/* RNG for unpriviledged user space with separated state from prandom_u32(). */
+static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
+
+void bpf_user_rnd_init_once(void)
+{
+	prandom_init_once(&bpf_user_rnd_state);
+}
+
+BPF_CALL_0(bpf_user_rnd_u32)
+{
+	/* Should someone ever have the rather unwise idea to use some
+	 * of the registers passed into this function, then note that
+	 * this function is called from native eBPF and classic-to-eBPF
+	 * transformations. Register assignments from both sides are
+	 * different, f.e. classic always sets fn(ctx, A, X) here.
+	 */
+	struct rnd_state *state;
+	u32 res;
+
+	state = &get_cpu_var(bpf_user_rnd_state);
+	res = prandom_u32_state(state);
+	put_cpu_var(bpf_user_rnd_state);
+
+	return res;
+}
+
+BPF_CALL_0(bpf_get_raw_cpu_id)
+{
+	return raw_smp_processor_id();
+}
+
+/* Weak definitions of helper functions in case we don't have bpf syscall. */
+const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
+const struct bpf_func_proto bpf_map_update_elem_proto __weak;
+const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
+const struct bpf_func_proto bpf_map_push_elem_proto __weak;
+const struct bpf_func_proto bpf_map_pop_elem_proto __weak;
+const struct bpf_func_proto bpf_map_peek_elem_proto __weak;
+const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak;
+const struct bpf_func_proto bpf_spin_lock_proto __weak;
+const struct bpf_func_proto bpf_spin_unlock_proto __weak;
+const struct bpf_func_proto bpf_jiffies64_proto __weak;
+
+const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
+const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
+const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
+const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
+const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak;
+const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak;
+const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak;
+
+const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
+const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
+const struct bpf_func_proto bpf_get_current_comm_proto __weak;
+const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak;
+const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak;
+const struct bpf_func_proto bpf_get_local_storage_proto __weak;
+const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak;
+const struct bpf_func_proto bpf_snprintf_btf_proto __weak;
+const struct bpf_func_proto bpf_seq_printf_btf_proto __weak;
+const struct bpf_func_proto bpf_set_retval_proto __weak;
+const struct bpf_func_proto bpf_get_retval_proto __weak;
+
+const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
+{
+	return NULL;
+}
+
+const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void)
+{
+	return NULL;
+}
+
+u64 __weak
+bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
+		 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
+{
+	return -ENOTSUPP;
+}
+EXPORT_SYMBOL_GPL(bpf_event_output);
+
+/* Always built-in helper functions. */
+const struct bpf_func_proto bpf_tail_call_proto = {
+	.func		= NULL,
+	.gpl_only	= false,
+	.ret_type	= RET_VOID,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_CONST_MAP_PTR,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+/* Stub for JITs that only support cBPF. eBPF programs are interpreted.
+ * It is encouraged to implement bpf_int_jit_compile() instead, so that
+ * eBPF and implicitly also cBPF can get JITed!
+ */
+struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
+{
+	return prog;
+}
+
+/* Stub for JITs that support eBPF. All cBPF code gets transformed into
+ * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
+ */
+void __weak bpf_jit_compile(struct bpf_prog *prog)
+{
+}
+
+bool __weak bpf_helper_changes_pkt_data(void *func)
+{
+	return false;
+}
+
+/* Return TRUE if the JIT backend wants verifier to enable sub-register usage
+ * analysis code and wants explicit zero extension inserted by verifier.
+ * Otherwise, return FALSE.
+ *
+ * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if
+ * you don't override this. JITs that don't want these extra insns can detect
+ * them using insn_is_zext.
+ */
+bool __weak bpf_jit_needs_zext(void)
+{
+	return false;
+}
+
+/* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */
+bool __weak bpf_jit_supports_subprog_tailcalls(void)
+{
+	return false;
+}
+
+bool __weak bpf_jit_supports_kfunc_call(void)
+{
+	return false;
+}
+
+/* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
+ * skb_copy_bits(), so provide a weak definition of it for NET-less config.
+ */
+int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
+			 int len)
+{
+	return -EFAULT;
+}
+
+int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
+			      void *addr1, void *addr2)
+{
+	return -ENOTSUPP;
+}
+
+void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len)
+{
+	return ERR_PTR(-ENOTSUPP);
+}
+
+int __weak bpf_arch_text_invalidate(void *dst, size_t len)
+{
+	return -ENOTSUPP;
+}
+
+DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
+EXPORT_SYMBOL(bpf_stats_enabled_key);
+
+/* All definitions of tracepoints related to BPF. */
+#define CREATE_TRACE_POINTS
+#include <linux/bpf_trace.h>
+
+EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
+EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx);
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
new file mode 100644
index 000000000..08a8e8102
--- /dev/null
+++ b/kernel/bpf/cpumap.c
@@ -0,0 +1,817 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* bpf/cpumap.c
+ *
+ * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
+ */
+
+/* The 'cpumap' is primarily used as a backend map for XDP BPF helper
+ * call bpf_redirect_map() and XDP_REDIRECT action, like 'devmap'.
+ *
+ * Unlike devmap which redirects XDP frames out another NIC device,
+ * this map type redirects raw XDP frames to another CPU.  The remote
+ * CPU will do SKB-allocation and call the normal network stack.
+ *
+ * This is a scalability and isolation mechanism, that allow
+ * separating the early driver network XDP layer, from the rest of the
+ * netstack, and assigning dedicated CPUs for this stage.  This
+ * basically allows for 10G wirespeed pre-filtering via bpf.
+ */
+#include <linux/bitops.h>
+#include <linux/bpf.h>
+#include <linux/filter.h>
+#include <linux/ptr_ring.h>
+#include <net/xdp.h>
+
+#include <linux/sched.h>
+#include <linux/workqueue.h>
+#include <linux/kthread.h>
+#include <linux/capability.h>
+#include <linux/completion.h>
+#include <trace/events/xdp.h>
+#include <linux/btf_ids.h>
+
+#include <linux/netdevice.h>   /* netif_receive_skb_list */
+#include <linux/etherdevice.h> /* eth_type_trans */
+
+/* General idea: XDP packets getting XDP redirected to another CPU,
+ * will maximum be stored/queued for one driver ->poll() call.  It is
+ * guaranteed that queueing the frame and the flush operation happen on
+ * same CPU.  Thus, cpu_map_flush operation can deduct via this_cpu_ptr()
+ * which queue in bpf_cpu_map_entry contains packets.
+ */
+
+#define CPU_MAP_BULK_SIZE 8  /* 8 == one cacheline on 64-bit archs */
+struct bpf_cpu_map_entry;
+struct bpf_cpu_map;
+
+struct xdp_bulk_queue {
+	void *q[CPU_MAP_BULK_SIZE];
+	struct list_head flush_node;
+	struct bpf_cpu_map_entry *obj;
+	unsigned int count;
+};
+
+/* Struct for every remote "destination" CPU in map */
+struct bpf_cpu_map_entry {
+	u32 cpu;    /* kthread CPU and map index */
+	int map_id; /* Back reference to map */
+
+	/* XDP can run multiple RX-ring queues, need __percpu enqueue store */
+	struct xdp_bulk_queue __percpu *bulkq;
+
+	struct bpf_cpu_map *cmap;
+
+	/* Queue with potential multi-producers, and single-consumer kthread */
+	struct ptr_ring *queue;
+	struct task_struct *kthread;
+
+	struct bpf_cpumap_val value;
+	struct bpf_prog *prog;
+
+	atomic_t refcnt; /* Control when this struct can be free'ed */
+	struct rcu_head rcu;
+
+	struct work_struct kthread_stop_wq;
+	struct completion kthread_running;
+};
+
+struct bpf_cpu_map {
+	struct bpf_map map;
+	/* Below members specific for map type */
+	struct bpf_cpu_map_entry __rcu **cpu_map;
+};
+
+static DEFINE_PER_CPU(struct list_head, cpu_map_flush_list);
+
+static struct bpf_map *cpu_map_alloc(union bpf_attr *attr)
+{
+	u32 value_size = attr->value_size;
+	struct bpf_cpu_map *cmap;
+	int err = -ENOMEM;
+
+	if (!bpf_capable())
+		return ERR_PTR(-EPERM);
+
+	/* check sanity of attributes */
+	if (attr->max_entries == 0 || attr->key_size != 4 ||
+	    (value_size != offsetofend(struct bpf_cpumap_val, qsize) &&
+	     value_size != offsetofend(struct bpf_cpumap_val, bpf_prog.fd)) ||
+	    attr->map_flags & ~BPF_F_NUMA_NODE)
+		return ERR_PTR(-EINVAL);
+
+	cmap = bpf_map_area_alloc(sizeof(*cmap), NUMA_NO_NODE);
+	if (!cmap)
+		return ERR_PTR(-ENOMEM);
+
+	bpf_map_init_from_attr(&cmap->map, attr);
+
+	/* Pre-limit array size based on NR_CPUS, not final CPU check */
+	if (cmap->map.max_entries > NR_CPUS) {
+		err = -E2BIG;
+		goto free_cmap;
+	}
+
+	/* Alloc array for possible remote "destination" CPUs */
+	cmap->cpu_map = bpf_map_area_alloc(cmap->map.max_entries *
+					   sizeof(struct bpf_cpu_map_entry *),
+					   cmap->map.numa_node);
+	if (!cmap->cpu_map)
+		goto free_cmap;
+
+	return &cmap->map;
+free_cmap:
+	bpf_map_area_free(cmap);
+	return ERR_PTR(err);
+}
+
+static void get_cpu_map_entry(struct bpf_cpu_map_entry *rcpu)
+{
+	atomic_inc(&rcpu->refcnt);
+}
+
+static void __cpu_map_ring_cleanup(struct ptr_ring *ring)
+{
+	/* The tear-down procedure should have made sure that queue is
+	 * empty.  See __cpu_map_entry_replace() and work-queue
+	 * invoked cpu_map_kthread_stop(). Catch any broken behaviour
+	 * gracefully and warn once.
+	 */
+	void *ptr;
+
+	while ((ptr = ptr_ring_consume(ring))) {
+		WARN_ON_ONCE(1);
+		if (unlikely(__ptr_test_bit(0, &ptr))) {
+			__ptr_clear_bit(0, &ptr);
+			kfree_skb(ptr);
+			continue;
+		}
+		xdp_return_frame(ptr);
+	}
+}
+
+static void put_cpu_map_entry(struct bpf_cpu_map_entry *rcpu)
+{
+	if (atomic_dec_and_test(&rcpu->refcnt)) {
+		if (rcpu->prog)
+			bpf_prog_put(rcpu->prog);
+		/* The queue should be empty at this point */
+		__cpu_map_ring_cleanup(rcpu->queue);
+		ptr_ring_cleanup(rcpu->queue, NULL);
+		kfree(rcpu->queue);
+		kfree(rcpu);
+	}
+}
+
+/* called from workqueue, to workaround syscall using preempt_disable */
+static void cpu_map_kthread_stop(struct work_struct *work)
+{
+	struct bpf_cpu_map_entry *rcpu;
+
+	rcpu = container_of(work, struct bpf_cpu_map_entry, kthread_stop_wq);
+
+	/* Wait for flush in __cpu_map_entry_free(), via full RCU barrier,
+	 * as it waits until all in-flight call_rcu() callbacks complete.
+	 */
+	rcu_barrier();
+
+	/* kthread_stop will wake_up_process and wait for it to complete */
+	kthread_stop(rcpu->kthread);
+}
+
+static void cpu_map_bpf_prog_run_skb(struct bpf_cpu_map_entry *rcpu,
+				     struct list_head *listp,
+				     struct xdp_cpumap_stats *stats)
+{
+	struct sk_buff *skb, *tmp;
+	struct xdp_buff xdp;
+	u32 act;
+	int err;
+
+	list_for_each_entry_safe(skb, tmp, listp, list) {
+		act = bpf_prog_run_generic_xdp(skb, &xdp, rcpu->prog);
+		switch (act) {
+		case XDP_PASS:
+			break;
+		case XDP_REDIRECT:
+			skb_list_del_init(skb);
+			err = xdp_do_generic_redirect(skb->dev, skb, &xdp,
+						      rcpu->prog);
+			if (unlikely(err)) {
+				kfree_skb(skb);
+				stats->drop++;
+			} else {
+				stats->redirect++;
+			}
+			return;
+		default:
+			bpf_warn_invalid_xdp_action(NULL, rcpu->prog, act);
+			fallthrough;
+		case XDP_ABORTED:
+			trace_xdp_exception(skb->dev, rcpu->prog, act);
+			fallthrough;
+		case XDP_DROP:
+			skb_list_del_init(skb);
+			kfree_skb(skb);
+			stats->drop++;
+			return;
+		}
+	}
+}
+
+static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu,
+				    void **frames, int n,
+				    struct xdp_cpumap_stats *stats)
+{
+	struct xdp_rxq_info rxq;
+	struct xdp_buff xdp;
+	int i, nframes = 0;
+
+	xdp_set_return_frame_no_direct();
+	xdp.rxq = &rxq;
+
+	for (i = 0; i < n; i++) {
+		struct xdp_frame *xdpf = frames[i];
+		u32 act;
+		int err;
+
+		rxq.dev = xdpf->dev_rx;
+		rxq.mem = xdpf->mem;
+		/* TODO: report queue_index to xdp_rxq_info */
+
+		xdp_convert_frame_to_buff(xdpf, &xdp);
+
+		act = bpf_prog_run_xdp(rcpu->prog, &xdp);
+		switch (act) {
+		case XDP_PASS:
+			err = xdp_update_frame_from_buff(&xdp, xdpf);
+			if (err < 0) {
+				xdp_return_frame(xdpf);
+				stats->drop++;
+			} else {
+				frames[nframes++] = xdpf;
+				stats->pass++;
+			}
+			break;
+		case XDP_REDIRECT:
+			err = xdp_do_redirect(xdpf->dev_rx, &xdp,
+					      rcpu->prog);
+			if (unlikely(err)) {
+				xdp_return_frame(xdpf);
+				stats->drop++;
+			} else {
+				stats->redirect++;
+			}
+			break;
+		default:
+			bpf_warn_invalid_xdp_action(NULL, rcpu->prog, act);
+			fallthrough;
+		case XDP_DROP:
+			xdp_return_frame(xdpf);
+			stats->drop++;
+			break;
+		}
+	}
+
+	xdp_clear_return_frame_no_direct();
+
+	return nframes;
+}
+
+#define CPUMAP_BATCH 8
+
+static int cpu_map_bpf_prog_run(struct bpf_cpu_map_entry *rcpu, void **frames,
+				int xdp_n, struct xdp_cpumap_stats *stats,
+				struct list_head *list)
+{
+	int nframes;
+
+	if (!rcpu->prog)
+		return xdp_n;
+
+	rcu_read_lock_bh();
+
+	nframes = cpu_map_bpf_prog_run_xdp(rcpu, frames, xdp_n, stats);
+
+	if (stats->redirect)
+		xdp_do_flush();
+
+	if (unlikely(!list_empty(list)))
+		cpu_map_bpf_prog_run_skb(rcpu, list, stats);
+
+	rcu_read_unlock_bh(); /* resched point, may call do_softirq() */
+
+	return nframes;
+}
+
+static int cpu_map_kthread_run(void *data)
+{
+	struct bpf_cpu_map_entry *rcpu = data;
+
+	complete(&rcpu->kthread_running);
+	set_current_state(TASK_INTERRUPTIBLE);
+
+	/* When kthread gives stop order, then rcpu have been disconnected
+	 * from map, thus no new packets can enter. Remaining in-flight
+	 * per CPU stored packets are flushed to this queue.  Wait honoring
+	 * kthread_stop signal until queue is empty.
+	 */
+	while (!kthread_should_stop() || !__ptr_ring_empty(rcpu->queue)) {
+		struct xdp_cpumap_stats stats = {}; /* zero stats */
+		unsigned int kmem_alloc_drops = 0, sched = 0;
+		gfp_t gfp = __GFP_ZERO | GFP_ATOMIC;
+		int i, n, m, nframes, xdp_n;
+		void *frames[CPUMAP_BATCH];
+		void *skbs[CPUMAP_BATCH];
+		LIST_HEAD(list);
+
+		/* Release CPU reschedule checks */
+		if (__ptr_ring_empty(rcpu->queue)) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			/* Recheck to avoid lost wake-up */
+			if (__ptr_ring_empty(rcpu->queue)) {
+				schedule();
+				sched = 1;
+			} else {
+				__set_current_state(TASK_RUNNING);
+			}
+		} else {
+			sched = cond_resched();
+		}
+
+		/*
+		 * The bpf_cpu_map_entry is single consumer, with this
+		 * kthread CPU pinned. Lockless access to ptr_ring
+		 * consume side valid as no-resize allowed of queue.
+		 */
+		n = __ptr_ring_consume_batched(rcpu->queue, frames,
+					       CPUMAP_BATCH);
+		for (i = 0, xdp_n = 0; i < n; i++) {
+			void *f = frames[i];
+			struct page *page;
+
+			if (unlikely(__ptr_test_bit(0, &f))) {
+				struct sk_buff *skb = f;
+
+				__ptr_clear_bit(0, &skb);
+				list_add_tail(&skb->list, &list);
+				continue;
+			}
+
+			frames[xdp_n++] = f;
+			page = virt_to_page(f);
+
+			/* Bring struct page memory area to curr CPU. Read by
+			 * build_skb_around via page_is_pfmemalloc(), and when
+			 * freed written by page_frag_free call.
+			 */
+			prefetchw(page);
+		}
+
+		/* Support running another XDP prog on this CPU */
+		nframes = cpu_map_bpf_prog_run(rcpu, frames, xdp_n, &stats, &list);
+		if (nframes) {
+			m = kmem_cache_alloc_bulk(skbuff_head_cache, gfp, nframes, skbs);
+			if (unlikely(m == 0)) {
+				for (i = 0; i < nframes; i++)
+					skbs[i] = NULL; /* effect: xdp_return_frame */
+				kmem_alloc_drops += nframes;
+			}
+		}
+
+		local_bh_disable();
+		for (i = 0; i < nframes; i++) {
+			struct xdp_frame *xdpf = frames[i];
+			struct sk_buff *skb = skbs[i];
+
+			skb = __xdp_build_skb_from_frame(xdpf, skb,
+							 xdpf->dev_rx);
+			if (!skb) {
+				xdp_return_frame(xdpf);
+				continue;
+			}
+
+			list_add_tail(&skb->list, &list);
+		}
+		netif_receive_skb_list(&list);
+
+		/* Feedback loop via tracepoint */
+		trace_xdp_cpumap_kthread(rcpu->map_id, n, kmem_alloc_drops,
+					 sched, &stats);
+
+		local_bh_enable(); /* resched point, may call do_softirq() */
+	}
+	__set_current_state(TASK_RUNNING);
+
+	put_cpu_map_entry(rcpu);
+	return 0;
+}
+
+static int __cpu_map_load_bpf_program(struct bpf_cpu_map_entry *rcpu,
+				      struct bpf_map *map, int fd)
+{
+	struct bpf_prog *prog;
+
+	prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_XDP);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
+	if (prog->expected_attach_type != BPF_XDP_CPUMAP ||
+	    !bpf_prog_map_compatible(map, prog)) {
+		bpf_prog_put(prog);
+		return -EINVAL;
+	}
+
+	rcpu->value.bpf_prog.id = prog->aux->id;
+	rcpu->prog = prog;
+
+	return 0;
+}
+
+static struct bpf_cpu_map_entry *
+__cpu_map_entry_alloc(struct bpf_map *map, struct bpf_cpumap_val *value,
+		      u32 cpu)
+{
+	int numa, err, i, fd = value->bpf_prog.fd;
+	gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
+	struct bpf_cpu_map_entry *rcpu;
+	struct xdp_bulk_queue *bq;
+
+	/* Have map->numa_node, but choose node of redirect target CPU */
+	numa = cpu_to_node(cpu);
+
+	rcpu = bpf_map_kmalloc_node(map, sizeof(*rcpu), gfp | __GFP_ZERO, numa);
+	if (!rcpu)
+		return NULL;
+
+	/* Alloc percpu bulkq */
+	rcpu->bulkq = bpf_map_alloc_percpu(map, sizeof(*rcpu->bulkq),
+					   sizeof(void *), gfp);
+	if (!rcpu->bulkq)
+		goto free_rcu;
+
+	for_each_possible_cpu(i) {
+		bq = per_cpu_ptr(rcpu->bulkq, i);
+		bq->obj = rcpu;
+	}
+
+	/* Alloc queue */
+	rcpu->queue = bpf_map_kmalloc_node(map, sizeof(*rcpu->queue), gfp,
+					   numa);
+	if (!rcpu->queue)
+		goto free_bulkq;
+
+	err = ptr_ring_init(rcpu->queue, value->qsize, gfp);
+	if (err)
+		goto free_queue;
+
+	rcpu->cpu    = cpu;
+	rcpu->map_id = map->id;
+	rcpu->value.qsize  = value->qsize;
+
+	if (fd > 0 && __cpu_map_load_bpf_program(rcpu, map, fd))
+		goto free_ptr_ring;
+
+	/* Setup kthread */
+	init_completion(&rcpu->kthread_running);
+	rcpu->kthread = kthread_create_on_node(cpu_map_kthread_run, rcpu, numa,
+					       "cpumap/%d/map:%d", cpu,
+					       map->id);
+	if (IS_ERR(rcpu->kthread))
+		goto free_prog;
+
+	get_cpu_map_entry(rcpu); /* 1-refcnt for being in cmap->cpu_map[] */
+	get_cpu_map_entry(rcpu); /* 1-refcnt for kthread */
+
+	/* Make sure kthread runs on a single CPU */
+	kthread_bind(rcpu->kthread, cpu);
+	wake_up_process(rcpu->kthread);
+
+	/* Make sure kthread has been running, so kthread_stop() will not
+	 * stop the kthread prematurely and all pending frames or skbs
+	 * will be handled by the kthread before kthread_stop() returns.
+	 */
+	wait_for_completion(&rcpu->kthread_running);
+
+	return rcpu;
+
+free_prog:
+	if (rcpu->prog)
+		bpf_prog_put(rcpu->prog);
+free_ptr_ring:
+	ptr_ring_cleanup(rcpu->queue, NULL);
+free_queue:
+	kfree(rcpu->queue);
+free_bulkq:
+	free_percpu(rcpu->bulkq);
+free_rcu:
+	kfree(rcpu);
+	return NULL;
+}
+
+static void __cpu_map_entry_free(struct rcu_head *rcu)
+{
+	struct bpf_cpu_map_entry *rcpu;
+
+	/* This cpu_map_entry have been disconnected from map and one
+	 * RCU grace-period have elapsed.  Thus, XDP cannot queue any
+	 * new packets and cannot change/set flush_needed that can
+	 * find this entry.
+	 */
+	rcpu = container_of(rcu, struct bpf_cpu_map_entry, rcu);
+
+	free_percpu(rcpu->bulkq);
+	/* Cannot kthread_stop() here, last put free rcpu resources */
+	put_cpu_map_entry(rcpu);
+}
+
+/* After xchg pointer to bpf_cpu_map_entry, use the call_rcu() to
+ * ensure any driver rcu critical sections have completed, but this
+ * does not guarantee a flush has happened yet. Because driver side
+ * rcu_read_lock/unlock only protects the running XDP program.  The
+ * atomic xchg and NULL-ptr check in __cpu_map_flush() makes sure a
+ * pending flush op doesn't fail.
+ *
+ * The bpf_cpu_map_entry is still used by the kthread, and there can
+ * still be pending packets (in queue and percpu bulkq).  A refcnt
+ * makes sure to last user (kthread_stop vs. call_rcu) free memory
+ * resources.
+ *
+ * The rcu callback __cpu_map_entry_free flush remaining packets in
+ * percpu bulkq to queue.  Due to caller map_delete_elem() disable
+ * preemption, cannot call kthread_stop() to make sure queue is empty.
+ * Instead a work_queue is started for stopping kthread,
+ * cpu_map_kthread_stop, which waits for an RCU grace period before
+ * stopping kthread, emptying the queue.
+ */
+static void __cpu_map_entry_replace(struct bpf_cpu_map *cmap,
+				    u32 key_cpu, struct bpf_cpu_map_entry *rcpu)
+{
+	struct bpf_cpu_map_entry *old_rcpu;
+
+	old_rcpu = unrcu_pointer(xchg(&cmap->cpu_map[key_cpu], RCU_INITIALIZER(rcpu)));
+	if (old_rcpu) {
+		call_rcu(&old_rcpu->rcu, __cpu_map_entry_free);
+		INIT_WORK(&old_rcpu->kthread_stop_wq, cpu_map_kthread_stop);
+		schedule_work(&old_rcpu->kthread_stop_wq);
+	}
+}
+
+static int cpu_map_delete_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map);
+	u32 key_cpu = *(u32 *)key;
+
+	if (key_cpu >= map->max_entries)
+		return -EINVAL;
+
+	/* notice caller map_delete_elem() use preempt_disable() */
+	__cpu_map_entry_replace(cmap, key_cpu, NULL);
+	return 0;
+}
+
+static int cpu_map_update_elem(struct bpf_map *map, void *key, void *value,
+			       u64 map_flags)
+{
+	struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map);
+	struct bpf_cpumap_val cpumap_value = {};
+	struct bpf_cpu_map_entry *rcpu;
+	/* Array index key correspond to CPU number */
+	u32 key_cpu = *(u32 *)key;
+
+	memcpy(&cpumap_value, value, map->value_size);
+
+	if (unlikely(map_flags > BPF_EXIST))
+		return -EINVAL;
+	if (unlikely(key_cpu >= cmap->map.max_entries))
+		return -E2BIG;
+	if (unlikely(map_flags == BPF_NOEXIST))
+		return -EEXIST;
+	if (unlikely(cpumap_value.qsize > 16384)) /* sanity limit on qsize */
+		return -EOVERFLOW;
+
+	/* Make sure CPU is a valid possible cpu */
+	if (key_cpu >= nr_cpumask_bits || !cpu_possible(key_cpu))
+		return -ENODEV;
+
+	if (cpumap_value.qsize == 0) {
+		rcpu = NULL; /* Same as deleting */
+	} else {
+		/* Updating qsize cause re-allocation of bpf_cpu_map_entry */
+		rcpu = __cpu_map_entry_alloc(map, &cpumap_value, key_cpu);
+		if (!rcpu)
+			return -ENOMEM;
+		rcpu->cmap = cmap;
+	}
+	rcu_read_lock();
+	__cpu_map_entry_replace(cmap, key_cpu, rcpu);
+	rcu_read_unlock();
+	return 0;
+}
+
+static void cpu_map_free(struct bpf_map *map)
+{
+	struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map);
+	u32 i;
+
+	/* At this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
+	 * so the bpf programs (can be more than one that used this map) were
+	 * disconnected from events. Wait for outstanding critical sections in
+	 * these programs to complete. The rcu critical section only guarantees
+	 * no further "XDP/bpf-side" reads against bpf_cpu_map->cpu_map.
+	 * It does __not__ ensure pending flush operations (if any) are
+	 * complete.
+	 */
+
+	synchronize_rcu();
+
+	/* For cpu_map the remote CPUs can still be using the entries
+	 * (struct bpf_cpu_map_entry).
+	 */
+	for (i = 0; i < cmap->map.max_entries; i++) {
+		struct bpf_cpu_map_entry *rcpu;
+
+		rcpu = rcu_dereference_raw(cmap->cpu_map[i]);
+		if (!rcpu)
+			continue;
+
+		/* bq flush and cleanup happens after RCU grace-period */
+		__cpu_map_entry_replace(cmap, i, NULL); /* call_rcu */
+	}
+	bpf_map_area_free(cmap->cpu_map);
+	bpf_map_area_free(cmap);
+}
+
+/* Elements are kept alive by RCU; either by rcu_read_lock() (from syscall) or
+ * by local_bh_disable() (from XDP calls inside NAPI). The
+ * rcu_read_lock_bh_held() below makes lockdep accept both.
+ */
+static void *__cpu_map_lookup_elem(struct bpf_map *map, u32 key)
+{
+	struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map);
+	struct bpf_cpu_map_entry *rcpu;
+
+	if (key >= map->max_entries)
+		return NULL;
+
+	rcpu = rcu_dereference_check(cmap->cpu_map[key],
+				     rcu_read_lock_bh_held());
+	return rcpu;
+}
+
+static void *cpu_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_cpu_map_entry *rcpu =
+		__cpu_map_lookup_elem(map, *(u32 *)key);
+
+	return rcpu ? &rcpu->value : NULL;
+}
+
+static int cpu_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
+{
+	struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map);
+	u32 index = key ? *(u32 *)key : U32_MAX;
+	u32 *next = next_key;
+
+	if (index >= cmap->map.max_entries) {
+		*next = 0;
+		return 0;
+	}
+
+	if (index == cmap->map.max_entries - 1)
+		return -ENOENT;
+	*next = index + 1;
+	return 0;
+}
+
+static int cpu_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags)
+{
+	return __bpf_xdp_redirect_map(map, ifindex, flags, 0,
+				      __cpu_map_lookup_elem);
+}
+
+BTF_ID_LIST_SINGLE(cpu_map_btf_ids, struct, bpf_cpu_map)
+const struct bpf_map_ops cpu_map_ops = {
+	.map_meta_equal		= bpf_map_meta_equal,
+	.map_alloc		= cpu_map_alloc,
+	.map_free		= cpu_map_free,
+	.map_delete_elem	= cpu_map_delete_elem,
+	.map_update_elem	= cpu_map_update_elem,
+	.map_lookup_elem	= cpu_map_lookup_elem,
+	.map_get_next_key	= cpu_map_get_next_key,
+	.map_check_btf		= map_check_no_btf,
+	.map_btf_id		= &cpu_map_btf_ids[0],
+	.map_redirect		= cpu_map_redirect,
+};
+
+static void bq_flush_to_queue(struct xdp_bulk_queue *bq)
+{
+	struct bpf_cpu_map_entry *rcpu = bq->obj;
+	unsigned int processed = 0, drops = 0;
+	const int to_cpu = rcpu->cpu;
+	struct ptr_ring *q;
+	int i;
+
+	if (unlikely(!bq->count))
+		return;
+
+	q = rcpu->queue;
+	spin_lock(&q->producer_lock);
+
+	for (i = 0; i < bq->count; i++) {
+		struct xdp_frame *xdpf = bq->q[i];
+		int err;
+
+		err = __ptr_ring_produce(q, xdpf);
+		if (err) {
+			drops++;
+			xdp_return_frame_rx_napi(xdpf);
+		}
+		processed++;
+	}
+	bq->count = 0;
+	spin_unlock(&q->producer_lock);
+
+	__list_del_clearprev(&bq->flush_node);
+
+	/* Feedback loop via tracepoints */
+	trace_xdp_cpumap_enqueue(rcpu->map_id, processed, drops, to_cpu);
+}
+
+/* Runs under RCU-read-side, plus in softirq under NAPI protection.
+ * Thus, safe percpu variable access.
+ */
+static void bq_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf)
+{
+	struct list_head *flush_list = this_cpu_ptr(&cpu_map_flush_list);
+	struct xdp_bulk_queue *bq = this_cpu_ptr(rcpu->bulkq);
+
+	if (unlikely(bq->count == CPU_MAP_BULK_SIZE))
+		bq_flush_to_queue(bq);
+
+	/* Notice, xdp_buff/page MUST be queued here, long enough for
+	 * driver to code invoking us to finished, due to driver
+	 * (e.g. ixgbe) recycle tricks based on page-refcnt.
+	 *
+	 * Thus, incoming xdp_frame is always queued here (else we race
+	 * with another CPU on page-refcnt and remaining driver code).
+	 * Queue time is very short, as driver will invoke flush
+	 * operation, when completing napi->poll call.
+	 */
+	bq->q[bq->count++] = xdpf;
+
+	if (!bq->flush_node.prev)
+		list_add(&bq->flush_node, flush_list);
+}
+
+int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf,
+		    struct net_device *dev_rx)
+{
+	/* Info needed when constructing SKB on remote CPU */
+	xdpf->dev_rx = dev_rx;
+
+	bq_enqueue(rcpu, xdpf);
+	return 0;
+}
+
+int cpu_map_generic_redirect(struct bpf_cpu_map_entry *rcpu,
+			     struct sk_buff *skb)
+{
+	int ret;
+
+	__skb_pull(skb, skb->mac_len);
+	skb_set_redirected(skb, false);
+	__ptr_set_bit(0, &skb);
+
+	ret = ptr_ring_produce(rcpu->queue, skb);
+	if (ret < 0)
+		goto trace;
+
+	wake_up_process(rcpu->kthread);
+trace:
+	trace_xdp_cpumap_enqueue(rcpu->map_id, !ret, !!ret, rcpu->cpu);
+	return ret;
+}
+
+void __cpu_map_flush(void)
+{
+	struct list_head *flush_list = this_cpu_ptr(&cpu_map_flush_list);
+	struct xdp_bulk_queue *bq, *tmp;
+
+	list_for_each_entry_safe(bq, tmp, flush_list, flush_node) {
+		bq_flush_to_queue(bq);
+
+		/* If already running, costs spin_lock_irqsave + smb_mb */
+		wake_up_process(bq->obj->kthread);
+	}
+}
+
+static int __init cpu_map_init(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		INIT_LIST_HEAD(&per_cpu(cpu_map_flush_list, cpu));
+	return 0;
+}
+
+subsys_initcall(cpu_map_init);
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
new file mode 100644
index 000000000..f9a87dcc5
--- /dev/null
+++ b/kernel/bpf/devmap.c
@@ -0,0 +1,1133 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
+ */
+
+/* Devmaps primary use is as a backend map for XDP BPF helper call
+ * bpf_redirect_map(). Because XDP is mostly concerned with performance we
+ * spent some effort to ensure the datapath with redirect maps does not use
+ * any locking. This is a quick note on the details.
+ *
+ * We have three possible paths to get into the devmap control plane bpf
+ * syscalls, bpf programs, and driver side xmit/flush operations. A bpf syscall
+ * will invoke an update, delete, or lookup operation. To ensure updates and
+ * deletes appear atomic from the datapath side xchg() is used to modify the
+ * netdev_map array. Then because the datapath does a lookup into the netdev_map
+ * array (read-only) from an RCU critical section we use call_rcu() to wait for
+ * an rcu grace period before free'ing the old data structures. This ensures the
+ * datapath always has a valid copy. However, the datapath does a "flush"
+ * operation that pushes any pending packets in the driver outside the RCU
+ * critical section. Each bpf_dtab_netdev tracks these pending operations using
+ * a per-cpu flush list. The bpf_dtab_netdev object will not be destroyed  until
+ * this list is empty, indicating outstanding flush operations have completed.
+ *
+ * BPF syscalls may race with BPF program calls on any of the update, delete
+ * or lookup operations. As noted above the xchg() operation also keep the
+ * netdev_map consistent in this case. From the devmap side BPF programs
+ * calling into these operations are the same as multiple user space threads
+ * making system calls.
+ *
+ * Finally, any of the above may race with a netdev_unregister notifier. The
+ * unregister notifier must search for net devices in the map structure that
+ * contain a reference to the net device and remove them. This is a two step
+ * process (a) dereference the bpf_dtab_netdev object in netdev_map and (b)
+ * check to see if the ifindex is the same as the net_device being removed.
+ * When removing the dev a cmpxchg() is used to ensure the correct dev is
+ * removed, in the case of a concurrent update or delete operation it is
+ * possible that the initially referenced dev is no longer in the map. As the
+ * notifier hook walks the map we know that new dev references can not be
+ * added by the user because core infrastructure ensures dev_get_by_index()
+ * calls will fail at this point.
+ *
+ * The devmap_hash type is a map type which interprets keys as ifindexes and
+ * indexes these using a hashmap. This allows maps that use ifindex as key to be
+ * densely packed instead of having holes in the lookup array for unused
+ * ifindexes. The setup and packet enqueue/send code is shared between the two
+ * types of devmap; only the lookup and insertion is different.
+ */
+#include <linux/bpf.h>
+#include <net/xdp.h>
+#include <linux/filter.h>
+#include <trace/events/xdp.h>
+#include <linux/btf_ids.h>
+
+#define DEV_CREATE_FLAG_MASK \
+	(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
+
+struct xdp_dev_bulk_queue {
+	struct xdp_frame *q[DEV_MAP_BULK_SIZE];
+	struct list_head flush_node;
+	struct net_device *dev;
+	struct net_device *dev_rx;
+	struct bpf_prog *xdp_prog;
+	unsigned int count;
+};
+
+struct bpf_dtab_netdev {
+	struct net_device *dev; /* must be first member, due to tracepoint */
+	struct hlist_node index_hlist;
+	struct bpf_dtab *dtab;
+	struct bpf_prog *xdp_prog;
+	struct rcu_head rcu;
+	unsigned int idx;
+	struct bpf_devmap_val val;
+};
+
+struct bpf_dtab {
+	struct bpf_map map;
+	struct bpf_dtab_netdev __rcu **netdev_map; /* DEVMAP type only */
+	struct list_head list;
+
+	/* these are only used for DEVMAP_HASH type maps */
+	struct hlist_head *dev_index_head;
+	spinlock_t index_lock;
+	unsigned int items;
+	u32 n_buckets;
+};
+
+static DEFINE_PER_CPU(struct list_head, dev_flush_list);
+static DEFINE_SPINLOCK(dev_map_lock);
+static LIST_HEAD(dev_map_list);
+
+static struct hlist_head *dev_map_create_hash(unsigned int entries,
+					      int numa_node)
+{
+	int i;
+	struct hlist_head *hash;
+
+	hash = bpf_map_area_alloc((u64) entries * sizeof(*hash), numa_node);
+	if (hash != NULL)
+		for (i = 0; i < entries; i++)
+			INIT_HLIST_HEAD(&hash[i]);
+
+	return hash;
+}
+
+static inline struct hlist_head *dev_map_index_hash(struct bpf_dtab *dtab,
+						    int idx)
+{
+	return &dtab->dev_index_head[idx & (dtab->n_buckets - 1)];
+}
+
+static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
+{
+	u32 valsize = attr->value_size;
+
+	/* check sanity of attributes. 2 value sizes supported:
+	 * 4 bytes: ifindex
+	 * 8 bytes: ifindex + prog fd
+	 */
+	if (attr->max_entries == 0 || attr->key_size != 4 ||
+	    (valsize != offsetofend(struct bpf_devmap_val, ifindex) &&
+	     valsize != offsetofend(struct bpf_devmap_val, bpf_prog.fd)) ||
+	    attr->map_flags & ~DEV_CREATE_FLAG_MASK)
+		return -EINVAL;
+
+	/* Lookup returns a pointer straight to dev->ifindex, so make sure the
+	 * verifier prevents writes from the BPF side
+	 */
+	attr->map_flags |= BPF_F_RDONLY_PROG;
+
+
+	bpf_map_init_from_attr(&dtab->map, attr);
+
+	if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+		dtab->n_buckets = roundup_pow_of_two(dtab->map.max_entries);
+
+		if (!dtab->n_buckets) /* Overflow check */
+			return -EINVAL;
+	}
+
+	if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+		dtab->dev_index_head = dev_map_create_hash(dtab->n_buckets,
+							   dtab->map.numa_node);
+		if (!dtab->dev_index_head)
+			return -ENOMEM;
+
+		spin_lock_init(&dtab->index_lock);
+	} else {
+		dtab->netdev_map = bpf_map_area_alloc((u64) dtab->map.max_entries *
+						      sizeof(struct bpf_dtab_netdev *),
+						      dtab->map.numa_node);
+		if (!dtab->netdev_map)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_dtab *dtab;
+	int err;
+
+	if (!capable(CAP_NET_ADMIN))
+		return ERR_PTR(-EPERM);
+
+	dtab = bpf_map_area_alloc(sizeof(*dtab), NUMA_NO_NODE);
+	if (!dtab)
+		return ERR_PTR(-ENOMEM);
+
+	err = dev_map_init_map(dtab, attr);
+	if (err) {
+		bpf_map_area_free(dtab);
+		return ERR_PTR(err);
+	}
+
+	spin_lock(&dev_map_lock);
+	list_add_tail_rcu(&dtab->list, &dev_map_list);
+	spin_unlock(&dev_map_lock);
+
+	return &dtab->map;
+}
+
+static void dev_map_free(struct bpf_map *map)
+{
+	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+	int i;
+
+	/* At this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
+	 * so the programs (can be more than one that used this map) were
+	 * disconnected from events. The following synchronize_rcu() guarantees
+	 * both rcu read critical sections complete and waits for
+	 * preempt-disable regions (NAPI being the relevant context here) so we
+	 * are certain there will be no further reads against the netdev_map and
+	 * all flush operations are complete. Flush operations can only be done
+	 * from NAPI context for this reason.
+	 */
+
+	spin_lock(&dev_map_lock);
+	list_del_rcu(&dtab->list);
+	spin_unlock(&dev_map_lock);
+
+	bpf_clear_redirect_map(map);
+	synchronize_rcu();
+
+	/* Make sure prior __dev_map_entry_free() have completed. */
+	rcu_barrier();
+
+	if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+		for (i = 0; i < dtab->n_buckets; i++) {
+			struct bpf_dtab_netdev *dev;
+			struct hlist_head *head;
+			struct hlist_node *next;
+
+			head = dev_map_index_hash(dtab, i);
+
+			hlist_for_each_entry_safe(dev, next, head, index_hlist) {
+				hlist_del_rcu(&dev->index_hlist);
+				if (dev->xdp_prog)
+					bpf_prog_put(dev->xdp_prog);
+				dev_put(dev->dev);
+				kfree(dev);
+			}
+		}
+
+		bpf_map_area_free(dtab->dev_index_head);
+	} else {
+		for (i = 0; i < dtab->map.max_entries; i++) {
+			struct bpf_dtab_netdev *dev;
+
+			dev = rcu_dereference_raw(dtab->netdev_map[i]);
+			if (!dev)
+				continue;
+
+			if (dev->xdp_prog)
+				bpf_prog_put(dev->xdp_prog);
+			dev_put(dev->dev);
+			kfree(dev);
+		}
+
+		bpf_map_area_free(dtab->netdev_map);
+	}
+
+	bpf_map_area_free(dtab);
+}
+
+static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
+{
+	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+	u32 index = key ? *(u32 *)key : U32_MAX;
+	u32 *next = next_key;
+
+	if (index >= dtab->map.max_entries) {
+		*next = 0;
+		return 0;
+	}
+
+	if (index == dtab->map.max_entries - 1)
+		return -ENOENT;
+	*next = index + 1;
+	return 0;
+}
+
+/* Elements are kept alive by RCU; either by rcu_read_lock() (from syscall) or
+ * by local_bh_disable() (from XDP calls inside NAPI). The
+ * rcu_read_lock_bh_held() below makes lockdep accept both.
+ */
+static void *__dev_map_hash_lookup_elem(struct bpf_map *map, u32 key)
+{
+	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+	struct hlist_head *head = dev_map_index_hash(dtab, key);
+	struct bpf_dtab_netdev *dev;
+
+	hlist_for_each_entry_rcu(dev, head, index_hlist,
+				 lockdep_is_held(&dtab->index_lock))
+		if (dev->idx == key)
+			return dev;
+
+	return NULL;
+}
+
+static int dev_map_hash_get_next_key(struct bpf_map *map, void *key,
+				    void *next_key)
+{
+	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+	u32 idx, *next = next_key;
+	struct bpf_dtab_netdev *dev, *next_dev;
+	struct hlist_head *head;
+	int i = 0;
+
+	if (!key)
+		goto find_first;
+
+	idx = *(u32 *)key;
+
+	dev = __dev_map_hash_lookup_elem(map, idx);
+	if (!dev)
+		goto find_first;
+
+	next_dev = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&dev->index_hlist)),
+				    struct bpf_dtab_netdev, index_hlist);
+
+	if (next_dev) {
+		*next = next_dev->idx;
+		return 0;
+	}
+
+	i = idx & (dtab->n_buckets - 1);
+	i++;
+
+ find_first:
+	for (; i < dtab->n_buckets; i++) {
+		head = dev_map_index_hash(dtab, i);
+
+		next_dev = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),
+					    struct bpf_dtab_netdev,
+					    index_hlist);
+		if (next_dev) {
+			*next = next_dev->idx;
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+
+static int dev_map_bpf_prog_run(struct bpf_prog *xdp_prog,
+				struct xdp_frame **frames, int n,
+				struct net_device *dev)
+{
+	struct xdp_txq_info txq = { .dev = dev };
+	struct xdp_buff xdp;
+	int i, nframes = 0;
+
+	for (i = 0; i < n; i++) {
+		struct xdp_frame *xdpf = frames[i];
+		u32 act;
+		int err;
+
+		xdp_convert_frame_to_buff(xdpf, &xdp);
+		xdp.txq = &txq;
+
+		act = bpf_prog_run_xdp(xdp_prog, &xdp);
+		switch (act) {
+		case XDP_PASS:
+			err = xdp_update_frame_from_buff(&xdp, xdpf);
+			if (unlikely(err < 0))
+				xdp_return_frame_rx_napi(xdpf);
+			else
+				frames[nframes++] = xdpf;
+			break;
+		default:
+			bpf_warn_invalid_xdp_action(NULL, xdp_prog, act);
+			fallthrough;
+		case XDP_ABORTED:
+			trace_xdp_exception(dev, xdp_prog, act);
+			fallthrough;
+		case XDP_DROP:
+			xdp_return_frame_rx_napi(xdpf);
+			break;
+		}
+	}
+	return nframes; /* sent frames count */
+}
+
+static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags)
+{
+	struct net_device *dev = bq->dev;
+	unsigned int cnt = bq->count;
+	int sent = 0, err = 0;
+	int to_send = cnt;
+	int i;
+
+	if (unlikely(!cnt))
+		return;
+
+	for (i = 0; i < cnt; i++) {
+		struct xdp_frame *xdpf = bq->q[i];
+
+		prefetch(xdpf);
+	}
+
+	if (bq->xdp_prog) {
+		to_send = dev_map_bpf_prog_run(bq->xdp_prog, bq->q, cnt, dev);
+		if (!to_send)
+			goto out;
+	}
+
+	sent = dev->netdev_ops->ndo_xdp_xmit(dev, to_send, bq->q, flags);
+	if (sent < 0) {
+		/* If ndo_xdp_xmit fails with an errno, no frames have
+		 * been xmit'ed.
+		 */
+		err = sent;
+		sent = 0;
+	}
+
+	/* If not all frames have been transmitted, it is our
+	 * responsibility to free them
+	 */
+	for (i = sent; unlikely(i < to_send); i++)
+		xdp_return_frame_rx_napi(bq->q[i]);
+
+out:
+	bq->count = 0;
+	trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, cnt - sent, err);
+}
+
+/* __dev_flush is called from xdp_do_flush() which _must_ be signalled from the
+ * driver before returning from its napi->poll() routine. See the comment above
+ * xdp_do_flush() in filter.c.
+ */
+void __dev_flush(void)
+{
+	struct list_head *flush_list = this_cpu_ptr(&dev_flush_list);
+	struct xdp_dev_bulk_queue *bq, *tmp;
+
+	list_for_each_entry_safe(bq, tmp, flush_list, flush_node) {
+		bq_xmit_all(bq, XDP_XMIT_FLUSH);
+		bq->dev_rx = NULL;
+		bq->xdp_prog = NULL;
+		__list_del_clearprev(&bq->flush_node);
+	}
+}
+
+/* Elements are kept alive by RCU; either by rcu_read_lock() (from syscall) or
+ * by local_bh_disable() (from XDP calls inside NAPI). The
+ * rcu_read_lock_bh_held() below makes lockdep accept both.
+ */
+static void *__dev_map_lookup_elem(struct bpf_map *map, u32 key)
+{
+	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+	struct bpf_dtab_netdev *obj;
+
+	if (key >= map->max_entries)
+		return NULL;
+
+	obj = rcu_dereference_check(dtab->netdev_map[key],
+				    rcu_read_lock_bh_held());
+	return obj;
+}
+
+/* Runs in NAPI, i.e., softirq under local_bh_disable(). Thus, safe percpu
+ * variable access, and map elements stick around. See comment above
+ * xdp_do_flush() in filter.c.
+ */
+static void bq_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
+		       struct net_device *dev_rx, struct bpf_prog *xdp_prog)
+{
+	struct list_head *flush_list = this_cpu_ptr(&dev_flush_list);
+	struct xdp_dev_bulk_queue *bq = this_cpu_ptr(dev->xdp_bulkq);
+
+	if (unlikely(bq->count == DEV_MAP_BULK_SIZE))
+		bq_xmit_all(bq, 0);
+
+	/* Ingress dev_rx will be the same for all xdp_frame's in
+	 * bulk_queue, because bq stored per-CPU and must be flushed
+	 * from net_device drivers NAPI func end.
+	 *
+	 * Do the same with xdp_prog and flush_list since these fields
+	 * are only ever modified together.
+	 */
+	if (!bq->dev_rx) {
+		bq->dev_rx = dev_rx;
+		bq->xdp_prog = xdp_prog;
+		list_add(&bq->flush_node, flush_list);
+	}
+
+	bq->q[bq->count++] = xdpf;
+}
+
+static inline int __xdp_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
+				struct net_device *dev_rx,
+				struct bpf_prog *xdp_prog)
+{
+	int err;
+
+	if (!dev->netdev_ops->ndo_xdp_xmit)
+		return -EOPNOTSUPP;
+
+	err = xdp_ok_fwd_dev(dev, xdp_get_frame_len(xdpf));
+	if (unlikely(err))
+		return err;
+
+	bq_enqueue(dev, xdpf, dev_rx, xdp_prog);
+	return 0;
+}
+
+static u32 dev_map_bpf_prog_run_skb(struct sk_buff *skb, struct bpf_dtab_netdev *dst)
+{
+	struct xdp_txq_info txq = { .dev = dst->dev };
+	struct xdp_buff xdp;
+	u32 act;
+
+	if (!dst->xdp_prog)
+		return XDP_PASS;
+
+	__skb_pull(skb, skb->mac_len);
+	xdp.txq = &txq;
+
+	act = bpf_prog_run_generic_xdp(skb, &xdp, dst->xdp_prog);
+	switch (act) {
+	case XDP_PASS:
+		__skb_push(skb, skb->mac_len);
+		break;
+	default:
+		bpf_warn_invalid_xdp_action(NULL, dst->xdp_prog, act);
+		fallthrough;
+	case XDP_ABORTED:
+		trace_xdp_exception(dst->dev, dst->xdp_prog, act);
+		fallthrough;
+	case XDP_DROP:
+		kfree_skb(skb);
+		break;
+	}
+
+	return act;
+}
+
+int dev_xdp_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
+		    struct net_device *dev_rx)
+{
+	return __xdp_enqueue(dev, xdpf, dev_rx, NULL);
+}
+
+int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_frame *xdpf,
+		    struct net_device *dev_rx)
+{
+	struct net_device *dev = dst->dev;
+
+	return __xdp_enqueue(dev, xdpf, dev_rx, dst->xdp_prog);
+}
+
+static bool is_valid_dst(struct bpf_dtab_netdev *obj, struct xdp_frame *xdpf)
+{
+	if (!obj ||
+	    !obj->dev->netdev_ops->ndo_xdp_xmit)
+		return false;
+
+	if (xdp_ok_fwd_dev(obj->dev, xdp_get_frame_len(xdpf)))
+		return false;
+
+	return true;
+}
+
+static int dev_map_enqueue_clone(struct bpf_dtab_netdev *obj,
+				 struct net_device *dev_rx,
+				 struct xdp_frame *xdpf)
+{
+	struct xdp_frame *nxdpf;
+
+	nxdpf = xdpf_clone(xdpf);
+	if (!nxdpf)
+		return -ENOMEM;
+
+	bq_enqueue(obj->dev, nxdpf, dev_rx, obj->xdp_prog);
+
+	return 0;
+}
+
+static inline bool is_ifindex_excluded(int *excluded, int num_excluded, int ifindex)
+{
+	while (num_excluded--) {
+		if (ifindex == excluded[num_excluded])
+			return true;
+	}
+	return false;
+}
+
+/* Get ifindex of each upper device. 'indexes' must be able to hold at
+ * least MAX_NEST_DEV elements.
+ * Returns the number of ifindexes added.
+ */
+static int get_upper_ifindexes(struct net_device *dev, int *indexes)
+{
+	struct net_device *upper;
+	struct list_head *iter;
+	int n = 0;
+
+	netdev_for_each_upper_dev_rcu(dev, upper, iter) {
+		indexes[n++] = upper->ifindex;
+	}
+	return n;
+}
+
+int dev_map_enqueue_multi(struct xdp_frame *xdpf, struct net_device *dev_rx,
+			  struct bpf_map *map, bool exclude_ingress)
+{
+	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+	struct bpf_dtab_netdev *dst, *last_dst = NULL;
+	int excluded_devices[1+MAX_NEST_DEV];
+	struct hlist_head *head;
+	int num_excluded = 0;
+	unsigned int i;
+	int err;
+
+	if (exclude_ingress) {
+		num_excluded = get_upper_ifindexes(dev_rx, excluded_devices);
+		excluded_devices[num_excluded++] = dev_rx->ifindex;
+	}
+
+	if (map->map_type == BPF_MAP_TYPE_DEVMAP) {
+		for (i = 0; i < map->max_entries; i++) {
+			dst = rcu_dereference_check(dtab->netdev_map[i],
+						    rcu_read_lock_bh_held());
+			if (!is_valid_dst(dst, xdpf))
+				continue;
+
+			if (is_ifindex_excluded(excluded_devices, num_excluded, dst->dev->ifindex))
+				continue;
+
+			/* we only need n-1 clones; last_dst enqueued below */
+			if (!last_dst) {
+				last_dst = dst;
+				continue;
+			}
+
+			err = dev_map_enqueue_clone(last_dst, dev_rx, xdpf);
+			if (err)
+				return err;
+
+			last_dst = dst;
+		}
+	} else { /* BPF_MAP_TYPE_DEVMAP_HASH */
+		for (i = 0; i < dtab->n_buckets; i++) {
+			head = dev_map_index_hash(dtab, i);
+			hlist_for_each_entry_rcu(dst, head, index_hlist,
+						 lockdep_is_held(&dtab->index_lock)) {
+				if (!is_valid_dst(dst, xdpf))
+					continue;
+
+				if (is_ifindex_excluded(excluded_devices, num_excluded,
+							dst->dev->ifindex))
+					continue;
+
+				/* we only need n-1 clones; last_dst enqueued below */
+				if (!last_dst) {
+					last_dst = dst;
+					continue;
+				}
+
+				err = dev_map_enqueue_clone(last_dst, dev_rx, xdpf);
+				if (err)
+					return err;
+
+				last_dst = dst;
+			}
+		}
+	}
+
+	/* consume the last copy of the frame */
+	if (last_dst)
+		bq_enqueue(last_dst->dev, xdpf, dev_rx, last_dst->xdp_prog);
+	else
+		xdp_return_frame_rx_napi(xdpf); /* dtab is empty */
+
+	return 0;
+}
+
+int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
+			     struct bpf_prog *xdp_prog)
+{
+	int err;
+
+	err = xdp_ok_fwd_dev(dst->dev, skb->len);
+	if (unlikely(err))
+		return err;
+
+	/* Redirect has already succeeded semantically at this point, so we just
+	 * return 0 even if packet is dropped. Helper below takes care of
+	 * freeing skb.
+	 */
+	if (dev_map_bpf_prog_run_skb(skb, dst) != XDP_PASS)
+		return 0;
+
+	skb->dev = dst->dev;
+	generic_xdp_tx(skb, xdp_prog);
+
+	return 0;
+}
+
+static int dev_map_redirect_clone(struct bpf_dtab_netdev *dst,
+				  struct sk_buff *skb,
+				  struct bpf_prog *xdp_prog)
+{
+	struct sk_buff *nskb;
+	int err;
+
+	nskb = skb_clone(skb, GFP_ATOMIC);
+	if (!nskb)
+		return -ENOMEM;
+
+	err = dev_map_generic_redirect(dst, nskb, xdp_prog);
+	if (unlikely(err)) {
+		consume_skb(nskb);
+		return err;
+	}
+
+	return 0;
+}
+
+int dev_map_redirect_multi(struct net_device *dev, struct sk_buff *skb,
+			   struct bpf_prog *xdp_prog, struct bpf_map *map,
+			   bool exclude_ingress)
+{
+	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+	struct bpf_dtab_netdev *dst, *last_dst = NULL;
+	int excluded_devices[1+MAX_NEST_DEV];
+	struct hlist_head *head;
+	struct hlist_node *next;
+	int num_excluded = 0;
+	unsigned int i;
+	int err;
+
+	if (exclude_ingress) {
+		num_excluded = get_upper_ifindexes(dev, excluded_devices);
+		excluded_devices[num_excluded++] = dev->ifindex;
+	}
+
+	if (map->map_type == BPF_MAP_TYPE_DEVMAP) {
+		for (i = 0; i < map->max_entries; i++) {
+			dst = rcu_dereference_check(dtab->netdev_map[i],
+						    rcu_read_lock_bh_held());
+			if (!dst)
+				continue;
+
+			if (is_ifindex_excluded(excluded_devices, num_excluded, dst->dev->ifindex))
+				continue;
+
+			/* we only need n-1 clones; last_dst enqueued below */
+			if (!last_dst) {
+				last_dst = dst;
+				continue;
+			}
+
+			err = dev_map_redirect_clone(last_dst, skb, xdp_prog);
+			if (err)
+				return err;
+
+			last_dst = dst;
+
+		}
+	} else { /* BPF_MAP_TYPE_DEVMAP_HASH */
+		for (i = 0; i < dtab->n_buckets; i++) {
+			head = dev_map_index_hash(dtab, i);
+			hlist_for_each_entry_safe(dst, next, head, index_hlist) {
+				if (!dst)
+					continue;
+
+				if (is_ifindex_excluded(excluded_devices, num_excluded,
+							dst->dev->ifindex))
+					continue;
+
+				/* we only need n-1 clones; last_dst enqueued below */
+				if (!last_dst) {
+					last_dst = dst;
+					continue;
+				}
+
+				err = dev_map_redirect_clone(last_dst, skb, xdp_prog);
+				if (err)
+					return err;
+
+				last_dst = dst;
+			}
+		}
+	}
+
+	/* consume the first skb and return */
+	if (last_dst)
+		return dev_map_generic_redirect(last_dst, skb, xdp_prog);
+
+	/* dtab is empty */
+	consume_skb(skb);
+	return 0;
+}
+
+static void *dev_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_dtab_netdev *obj = __dev_map_lookup_elem(map, *(u32 *)key);
+
+	return obj ? &obj->val : NULL;
+}
+
+static void *dev_map_hash_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_dtab_netdev *obj = __dev_map_hash_lookup_elem(map,
+								*(u32 *)key);
+	return obj ? &obj->val : NULL;
+}
+
+static void __dev_map_entry_free(struct rcu_head *rcu)
+{
+	struct bpf_dtab_netdev *dev;
+
+	dev = container_of(rcu, struct bpf_dtab_netdev, rcu);
+	if (dev->xdp_prog)
+		bpf_prog_put(dev->xdp_prog);
+	dev_put(dev->dev);
+	kfree(dev);
+}
+
+static int dev_map_delete_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+	struct bpf_dtab_netdev *old_dev;
+	int k = *(u32 *)key;
+
+	if (k >= map->max_entries)
+		return -EINVAL;
+
+	old_dev = unrcu_pointer(xchg(&dtab->netdev_map[k], NULL));
+	if (old_dev)
+		call_rcu(&old_dev->rcu, __dev_map_entry_free);
+	return 0;
+}
+
+static int dev_map_hash_delete_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+	struct bpf_dtab_netdev *old_dev;
+	int k = *(u32 *)key;
+	unsigned long flags;
+	int ret = -ENOENT;
+
+	spin_lock_irqsave(&dtab->index_lock, flags);
+
+	old_dev = __dev_map_hash_lookup_elem(map, k);
+	if (old_dev) {
+		dtab->items--;
+		hlist_del_init_rcu(&old_dev->index_hlist);
+		call_rcu(&old_dev->rcu, __dev_map_entry_free);
+		ret = 0;
+	}
+	spin_unlock_irqrestore(&dtab->index_lock, flags);
+
+	return ret;
+}
+
+static struct bpf_dtab_netdev *__dev_map_alloc_node(struct net *net,
+						    struct bpf_dtab *dtab,
+						    struct bpf_devmap_val *val,
+						    unsigned int idx)
+{
+	struct bpf_prog *prog = NULL;
+	struct bpf_dtab_netdev *dev;
+
+	dev = bpf_map_kmalloc_node(&dtab->map, sizeof(*dev),
+				   GFP_NOWAIT | __GFP_NOWARN,
+				   dtab->map.numa_node);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	dev->dev = dev_get_by_index(net, val->ifindex);
+	if (!dev->dev)
+		goto err_out;
+
+	if (val->bpf_prog.fd > 0) {
+		prog = bpf_prog_get_type_dev(val->bpf_prog.fd,
+					     BPF_PROG_TYPE_XDP, false);
+		if (IS_ERR(prog))
+			goto err_put_dev;
+		if (prog->expected_attach_type != BPF_XDP_DEVMAP ||
+		    !bpf_prog_map_compatible(&dtab->map, prog))
+			goto err_put_prog;
+	}
+
+	dev->idx = idx;
+	dev->dtab = dtab;
+	if (prog) {
+		dev->xdp_prog = prog;
+		dev->val.bpf_prog.id = prog->aux->id;
+	} else {
+		dev->xdp_prog = NULL;
+		dev->val.bpf_prog.id = 0;
+	}
+	dev->val.ifindex = val->ifindex;
+
+	return dev;
+err_put_prog:
+	bpf_prog_put(prog);
+err_put_dev:
+	dev_put(dev->dev);
+err_out:
+	kfree(dev);
+	return ERR_PTR(-EINVAL);
+}
+
+static int __dev_map_update_elem(struct net *net, struct bpf_map *map,
+				 void *key, void *value, u64 map_flags)
+{
+	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+	struct bpf_dtab_netdev *dev, *old_dev;
+	struct bpf_devmap_val val = {};
+	u32 i = *(u32 *)key;
+
+	if (unlikely(map_flags > BPF_EXIST))
+		return -EINVAL;
+	if (unlikely(i >= dtab->map.max_entries))
+		return -E2BIG;
+	if (unlikely(map_flags == BPF_NOEXIST))
+		return -EEXIST;
+
+	/* already verified value_size <= sizeof val */
+	memcpy(&val, value, map->value_size);
+
+	if (!val.ifindex) {
+		dev = NULL;
+		/* can not specify fd if ifindex is 0 */
+		if (val.bpf_prog.fd > 0)
+			return -EINVAL;
+	} else {
+		dev = __dev_map_alloc_node(net, dtab, &val, i);
+		if (IS_ERR(dev))
+			return PTR_ERR(dev);
+	}
+
+	/* Use call_rcu() here to ensure rcu critical sections have completed
+	 * Remembering the driver side flush operation will happen before the
+	 * net device is removed.
+	 */
+	old_dev = unrcu_pointer(xchg(&dtab->netdev_map[i], RCU_INITIALIZER(dev)));
+	if (old_dev)
+		call_rcu(&old_dev->rcu, __dev_map_entry_free);
+
+	return 0;
+}
+
+static int dev_map_update_elem(struct bpf_map *map, void *key, void *value,
+			       u64 map_flags)
+{
+	return __dev_map_update_elem(current->nsproxy->net_ns,
+				     map, key, value, map_flags);
+}
+
+static int __dev_map_hash_update_elem(struct net *net, struct bpf_map *map,
+				     void *key, void *value, u64 map_flags)
+{
+	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
+	struct bpf_dtab_netdev *dev, *old_dev;
+	struct bpf_devmap_val val = {};
+	u32 idx = *(u32 *)key;
+	unsigned long flags;
+	int err = -EEXIST;
+
+	/* already verified value_size <= sizeof val */
+	memcpy(&val, value, map->value_size);
+
+	if (unlikely(map_flags > BPF_EXIST || !val.ifindex))
+		return -EINVAL;
+
+	spin_lock_irqsave(&dtab->index_lock, flags);
+
+	old_dev = __dev_map_hash_lookup_elem(map, idx);
+	if (old_dev && (map_flags & BPF_NOEXIST))
+		goto out_err;
+
+	dev = __dev_map_alloc_node(net, dtab, &val, idx);
+	if (IS_ERR(dev)) {
+		err = PTR_ERR(dev);
+		goto out_err;
+	}
+
+	if (old_dev) {
+		hlist_del_rcu(&old_dev->index_hlist);
+	} else {
+		if (dtab->items >= dtab->map.max_entries) {
+			spin_unlock_irqrestore(&dtab->index_lock, flags);
+			call_rcu(&dev->rcu, __dev_map_entry_free);
+			return -E2BIG;
+		}
+		dtab->items++;
+	}
+
+	hlist_add_head_rcu(&dev->index_hlist,
+			   dev_map_index_hash(dtab, idx));
+	spin_unlock_irqrestore(&dtab->index_lock, flags);
+
+	if (old_dev)
+		call_rcu(&old_dev->rcu, __dev_map_entry_free);
+
+	return 0;
+
+out_err:
+	spin_unlock_irqrestore(&dtab->index_lock, flags);
+	return err;
+}
+
+static int dev_map_hash_update_elem(struct bpf_map *map, void *key, void *value,
+				   u64 map_flags)
+{
+	return __dev_map_hash_update_elem(current->nsproxy->net_ns,
+					 map, key, value, map_flags);
+}
+
+static int dev_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags)
+{
+	return __bpf_xdp_redirect_map(map, ifindex, flags,
+				      BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS,
+				      __dev_map_lookup_elem);
+}
+
+static int dev_hash_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags)
+{
+	return __bpf_xdp_redirect_map(map, ifindex, flags,
+				      BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS,
+				      __dev_map_hash_lookup_elem);
+}
+
+BTF_ID_LIST_SINGLE(dev_map_btf_ids, struct, bpf_dtab)
+const struct bpf_map_ops dev_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc = dev_map_alloc,
+	.map_free = dev_map_free,
+	.map_get_next_key = dev_map_get_next_key,
+	.map_lookup_elem = dev_map_lookup_elem,
+	.map_update_elem = dev_map_update_elem,
+	.map_delete_elem = dev_map_delete_elem,
+	.map_check_btf = map_check_no_btf,
+	.map_btf_id = &dev_map_btf_ids[0],
+	.map_redirect = dev_map_redirect,
+};
+
+const struct bpf_map_ops dev_map_hash_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc = dev_map_alloc,
+	.map_free = dev_map_free,
+	.map_get_next_key = dev_map_hash_get_next_key,
+	.map_lookup_elem = dev_map_hash_lookup_elem,
+	.map_update_elem = dev_map_hash_update_elem,
+	.map_delete_elem = dev_map_hash_delete_elem,
+	.map_check_btf = map_check_no_btf,
+	.map_btf_id = &dev_map_btf_ids[0],
+	.map_redirect = dev_hash_map_redirect,
+};
+
+static void dev_map_hash_remove_netdev(struct bpf_dtab *dtab,
+				       struct net_device *netdev)
+{
+	unsigned long flags;
+	u32 i;
+
+	spin_lock_irqsave(&dtab->index_lock, flags);
+	for (i = 0; i < dtab->n_buckets; i++) {
+		struct bpf_dtab_netdev *dev;
+		struct hlist_head *head;
+		struct hlist_node *next;
+
+		head = dev_map_index_hash(dtab, i);
+
+		hlist_for_each_entry_safe(dev, next, head, index_hlist) {
+			if (netdev != dev->dev)
+				continue;
+
+			dtab->items--;
+			hlist_del_rcu(&dev->index_hlist);
+			call_rcu(&dev->rcu, __dev_map_entry_free);
+		}
+	}
+	spin_unlock_irqrestore(&dtab->index_lock, flags);
+}
+
+static int dev_map_notification(struct notifier_block *notifier,
+				ulong event, void *ptr)
+{
+	struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
+	struct bpf_dtab *dtab;
+	int i, cpu;
+
+	switch (event) {
+	case NETDEV_REGISTER:
+		if (!netdev->netdev_ops->ndo_xdp_xmit || netdev->xdp_bulkq)
+			break;
+
+		/* will be freed in free_netdev() */
+		netdev->xdp_bulkq = alloc_percpu(struct xdp_dev_bulk_queue);
+		if (!netdev->xdp_bulkq)
+			return NOTIFY_BAD;
+
+		for_each_possible_cpu(cpu)
+			per_cpu_ptr(netdev->xdp_bulkq, cpu)->dev = netdev;
+		break;
+	case NETDEV_UNREGISTER:
+		/* This rcu_read_lock/unlock pair is needed because
+		 * dev_map_list is an RCU list AND to ensure a delete
+		 * operation does not free a netdev_map entry while we
+		 * are comparing it against the netdev being unregistered.
+		 */
+		rcu_read_lock();
+		list_for_each_entry_rcu(dtab, &dev_map_list, list) {
+			if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+				dev_map_hash_remove_netdev(dtab, netdev);
+				continue;
+			}
+
+			for (i = 0; i < dtab->map.max_entries; i++) {
+				struct bpf_dtab_netdev *dev, *odev;
+
+				dev = rcu_dereference(dtab->netdev_map[i]);
+				if (!dev || netdev != dev->dev)
+					continue;
+				odev = unrcu_pointer(cmpxchg(&dtab->netdev_map[i], RCU_INITIALIZER(dev), NULL));
+				if (dev == odev)
+					call_rcu(&dev->rcu,
+						 __dev_map_entry_free);
+			}
+		}
+		rcu_read_unlock();
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block dev_map_notifier = {
+	.notifier_call = dev_map_notification,
+};
+
+static int __init dev_map_init(void)
+{
+	int cpu;
+
+	/* Assure tracepoint shadow struct _bpf_dtab_netdev is in sync */
+	BUILD_BUG_ON(offsetof(struct bpf_dtab_netdev, dev) !=
+		     offsetof(struct _bpf_dtab_netdev, dev));
+	register_netdevice_notifier(&dev_map_notifier);
+
+	for_each_possible_cpu(cpu)
+		INIT_LIST_HEAD(&per_cpu(dev_flush_list, cpu));
+	return 0;
+}
+
+subsys_initcall(dev_map_init);
diff --git a/kernel/bpf/disasm.c b/kernel/bpf/disasm.c
new file mode 100644
index 000000000..7b4afb7d9
--- /dev/null
+++ b/kernel/bpf/disasm.c
@@ -0,0 +1,304 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ * Copyright (c) 2016 Facebook
+ */
+
+#include <linux/bpf.h>
+
+#include "disasm.h"
+
+#define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x)
+static const char * const func_id_str[] = {
+	__BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN)
+};
+#undef __BPF_FUNC_STR_FN
+
+static const char *__func_get_name(const struct bpf_insn_cbs *cbs,
+				   const struct bpf_insn *insn,
+				   char *buff, size_t len)
+{
+	BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID);
+
+	if (!insn->src_reg &&
+	    insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID &&
+	    func_id_str[insn->imm])
+		return func_id_str[insn->imm];
+
+	if (cbs && cbs->cb_call) {
+		const char *res;
+
+		res = cbs->cb_call(cbs->private_data, insn);
+		if (res)
+			return res;
+	}
+
+	if (insn->src_reg == BPF_PSEUDO_CALL)
+		snprintf(buff, len, "%+d", insn->imm);
+	else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL)
+		snprintf(buff, len, "kernel-function");
+
+	return buff;
+}
+
+static const char *__func_imm_name(const struct bpf_insn_cbs *cbs,
+				   const struct bpf_insn *insn,
+				   u64 full_imm, char *buff, size_t len)
+{
+	if (cbs && cbs->cb_imm)
+		return cbs->cb_imm(cbs->private_data, insn, full_imm);
+
+	snprintf(buff, len, "0x%llx", (unsigned long long)full_imm);
+	return buff;
+}
+
+const char *func_id_name(int id)
+{
+	if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id])
+		return func_id_str[id];
+	else
+		return "unknown";
+}
+
+const char *const bpf_class_string[8] = {
+	[BPF_LD]    = "ld",
+	[BPF_LDX]   = "ldx",
+	[BPF_ST]    = "st",
+	[BPF_STX]   = "stx",
+	[BPF_ALU]   = "alu",
+	[BPF_JMP]   = "jmp",
+	[BPF_JMP32] = "jmp32",
+	[BPF_ALU64] = "alu64",
+};
+
+const char *const bpf_alu_string[16] = {
+	[BPF_ADD >> 4]  = "+=",
+	[BPF_SUB >> 4]  = "-=",
+	[BPF_MUL >> 4]  = "*=",
+	[BPF_DIV >> 4]  = "/=",
+	[BPF_OR  >> 4]  = "|=",
+	[BPF_AND >> 4]  = "&=",
+	[BPF_LSH >> 4]  = "<<=",
+	[BPF_RSH >> 4]  = ">>=",
+	[BPF_NEG >> 4]  = "neg",
+	[BPF_MOD >> 4]  = "%=",
+	[BPF_XOR >> 4]  = "^=",
+	[BPF_MOV >> 4]  = "=",
+	[BPF_ARSH >> 4] = "s>>=",
+	[BPF_END >> 4]  = "endian",
+};
+
+static const char *const bpf_atomic_alu_string[16] = {
+	[BPF_ADD >> 4]  = "add",
+	[BPF_AND >> 4]  = "and",
+	[BPF_OR >> 4]  = "or",
+	[BPF_XOR >> 4]  = "xor",
+};
+
+static const char *const bpf_ldst_string[] = {
+	[BPF_W >> 3]  = "u32",
+	[BPF_H >> 3]  = "u16",
+	[BPF_B >> 3]  = "u8",
+	[BPF_DW >> 3] = "u64",
+};
+
+static const char *const bpf_jmp_string[16] = {
+	[BPF_JA >> 4]   = "jmp",
+	[BPF_JEQ >> 4]  = "==",
+	[BPF_JGT >> 4]  = ">",
+	[BPF_JLT >> 4]  = "<",
+	[BPF_JGE >> 4]  = ">=",
+	[BPF_JLE >> 4]  = "<=",
+	[BPF_JSET >> 4] = "&",
+	[BPF_JNE >> 4]  = "!=",
+	[BPF_JSGT >> 4] = "s>",
+	[BPF_JSLT >> 4] = "s<",
+	[BPF_JSGE >> 4] = "s>=",
+	[BPF_JSLE >> 4] = "s<=",
+	[BPF_CALL >> 4] = "call",
+	[BPF_EXIT >> 4] = "exit",
+};
+
+static void print_bpf_end_insn(bpf_insn_print_t verbose,
+			       void *private_data,
+			       const struct bpf_insn *insn)
+{
+	verbose(private_data, "(%02x) r%d = %s%d r%d\n",
+		insn->code, insn->dst_reg,
+		BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le",
+		insn->imm, insn->dst_reg);
+}
+
+void print_bpf_insn(const struct bpf_insn_cbs *cbs,
+		    const struct bpf_insn *insn,
+		    bool allow_ptr_leaks)
+{
+	const bpf_insn_print_t verbose = cbs->cb_print;
+	u8 class = BPF_CLASS(insn->code);
+
+	if (class == BPF_ALU || class == BPF_ALU64) {
+		if (BPF_OP(insn->code) == BPF_END) {
+			if (class == BPF_ALU64)
+				verbose(cbs->private_data, "BUG_alu64_%02x\n", insn->code);
+			else
+				print_bpf_end_insn(verbose, cbs->private_data, insn);
+		} else if (BPF_OP(insn->code) == BPF_NEG) {
+			verbose(cbs->private_data, "(%02x) %c%d = -%c%d\n",
+				insn->code, class == BPF_ALU ? 'w' : 'r',
+				insn->dst_reg, class == BPF_ALU ? 'w' : 'r',
+				insn->dst_reg);
+		} else if (BPF_SRC(insn->code) == BPF_X) {
+			verbose(cbs->private_data, "(%02x) %c%d %s %c%d\n",
+				insn->code, class == BPF_ALU ? 'w' : 'r',
+				insn->dst_reg,
+				bpf_alu_string[BPF_OP(insn->code) >> 4],
+				class == BPF_ALU ? 'w' : 'r',
+				insn->src_reg);
+		} else {
+			verbose(cbs->private_data, "(%02x) %c%d %s %d\n",
+				insn->code, class == BPF_ALU ? 'w' : 'r',
+				insn->dst_reg,
+				bpf_alu_string[BPF_OP(insn->code) >> 4],
+				insn->imm);
+		}
+	} else if (class == BPF_STX) {
+		if (BPF_MODE(insn->code) == BPF_MEM)
+			verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = r%d\n",
+				insn->code,
+				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+				insn->dst_reg,
+				insn->off, insn->src_reg);
+		else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
+			 (insn->imm == BPF_ADD || insn->imm == BPF_AND ||
+			  insn->imm == BPF_OR || insn->imm == BPF_XOR)) {
+			verbose(cbs->private_data, "(%02x) lock *(%s *)(r%d %+d) %s r%d\n",
+				insn->code,
+				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+				insn->dst_reg, insn->off,
+				bpf_alu_string[BPF_OP(insn->imm) >> 4],
+				insn->src_reg);
+		} else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
+			   (insn->imm == (BPF_ADD | BPF_FETCH) ||
+			    insn->imm == (BPF_AND | BPF_FETCH) ||
+			    insn->imm == (BPF_OR | BPF_FETCH) ||
+			    insn->imm == (BPF_XOR | BPF_FETCH))) {
+			verbose(cbs->private_data, "(%02x) r%d = atomic%s_fetch_%s((%s *)(r%d %+d), r%d)\n",
+				insn->code, insn->src_reg,
+				BPF_SIZE(insn->code) == BPF_DW ? "64" : "",
+				bpf_atomic_alu_string[BPF_OP(insn->imm) >> 4],
+				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+				insn->dst_reg, insn->off, insn->src_reg);
+		} else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
+			   insn->imm == BPF_CMPXCHG) {
+			verbose(cbs->private_data, "(%02x) r0 = atomic%s_cmpxchg((%s *)(r%d %+d), r0, r%d)\n",
+				insn->code,
+				BPF_SIZE(insn->code) == BPF_DW ? "64" : "",
+				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+				insn->dst_reg, insn->off,
+				insn->src_reg);
+		} else if (BPF_MODE(insn->code) == BPF_ATOMIC &&
+			   insn->imm == BPF_XCHG) {
+			verbose(cbs->private_data, "(%02x) r%d = atomic%s_xchg((%s *)(r%d %+d), r%d)\n",
+				insn->code, insn->src_reg,
+				BPF_SIZE(insn->code) == BPF_DW ? "64" : "",
+				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+				insn->dst_reg, insn->off, insn->src_reg);
+		} else {
+			verbose(cbs->private_data, "BUG_%02x\n", insn->code);
+		}
+	} else if (class == BPF_ST) {
+		if (BPF_MODE(insn->code) == BPF_MEM) {
+			verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = %d\n",
+				insn->code,
+				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+				insn->dst_reg,
+				insn->off, insn->imm);
+		} else if (BPF_MODE(insn->code) == 0xc0 /* BPF_NOSPEC, no UAPI */) {
+			verbose(cbs->private_data, "(%02x) nospec\n", insn->code);
+		} else {
+			verbose(cbs->private_data, "BUG_st_%02x\n", insn->code);
+		}
+	} else if (class == BPF_LDX) {
+		if (BPF_MODE(insn->code) != BPF_MEM) {
+			verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code);
+			return;
+		}
+		verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)\n",
+			insn->code, insn->dst_reg,
+			bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+			insn->src_reg, insn->off);
+	} else if (class == BPF_LD) {
+		if (BPF_MODE(insn->code) == BPF_ABS) {
+			verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[%d]\n",
+				insn->code,
+				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+				insn->imm);
+		} else if (BPF_MODE(insn->code) == BPF_IND) {
+			verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[r%d + %d]\n",
+				insn->code,
+				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+				insn->src_reg, insn->imm);
+		} else if (BPF_MODE(insn->code) == BPF_IMM &&
+			   BPF_SIZE(insn->code) == BPF_DW) {
+			/* At this point, we already made sure that the second
+			 * part of the ldimm64 insn is accessible.
+			 */
+			u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
+			bool is_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD ||
+				      insn->src_reg == BPF_PSEUDO_MAP_VALUE;
+			char tmp[64];
+
+			if (is_ptr && !allow_ptr_leaks)
+				imm = 0;
+
+			verbose(cbs->private_data, "(%02x) r%d = %s\n",
+				insn->code, insn->dst_reg,
+				__func_imm_name(cbs, insn, imm,
+						tmp, sizeof(tmp)));
+		} else {
+			verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code);
+			return;
+		}
+	} else if (class == BPF_JMP32 || class == BPF_JMP) {
+		u8 opcode = BPF_OP(insn->code);
+
+		if (opcode == BPF_CALL) {
+			char tmp[64];
+
+			if (insn->src_reg == BPF_PSEUDO_CALL) {
+				verbose(cbs->private_data, "(%02x) call pc%s\n",
+					insn->code,
+					__func_get_name(cbs, insn,
+							tmp, sizeof(tmp)));
+			} else {
+				strcpy(tmp, "unknown");
+				verbose(cbs->private_data, "(%02x) call %s#%d\n", insn->code,
+					__func_get_name(cbs, insn,
+							tmp, sizeof(tmp)),
+					insn->imm);
+			}
+		} else if (insn->code == (BPF_JMP | BPF_JA)) {
+			verbose(cbs->private_data, "(%02x) goto pc%+d\n",
+				insn->code, insn->off);
+		} else if (insn->code == (BPF_JMP | BPF_EXIT)) {
+			verbose(cbs->private_data, "(%02x) exit\n", insn->code);
+		} else if (BPF_SRC(insn->code) == BPF_X) {
+			verbose(cbs->private_data,
+				"(%02x) if %c%d %s %c%d goto pc%+d\n",
+				insn->code, class == BPF_JMP32 ? 'w' : 'r',
+				insn->dst_reg,
+				bpf_jmp_string[BPF_OP(insn->code) >> 4],
+				class == BPF_JMP32 ? 'w' : 'r',
+				insn->src_reg, insn->off);
+		} else {
+			verbose(cbs->private_data,
+				"(%02x) if %c%d %s 0x%x goto pc%+d\n",
+				insn->code, class == BPF_JMP32 ? 'w' : 'r',
+				insn->dst_reg,
+				bpf_jmp_string[BPF_OP(insn->code) >> 4],
+				insn->imm, insn->off);
+		}
+	} else {
+		verbose(cbs->private_data, "(%02x) %s\n",
+			insn->code, bpf_class_string[class]);
+	}
+}
diff --git a/kernel/bpf/disasm.h b/kernel/bpf/disasm.h
new file mode 100644
index 000000000..a4b040793
--- /dev/null
+++ b/kernel/bpf/disasm.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ * Copyright (c) 2016 Facebook
+ */
+
+#ifndef __BPF_DISASM_H__
+#define __BPF_DISASM_H__
+
+#include <linux/bpf.h>
+#include <linux/kernel.h>
+#include <linux/stringify.h>
+#ifndef __KERNEL__
+#include <stdio.h>
+#include <string.h>
+#endif
+
+extern const char *const bpf_alu_string[16];
+extern const char *const bpf_class_string[8];
+
+const char *func_id_name(int id);
+
+typedef __printf(2, 3) void (*bpf_insn_print_t)(void *private_data,
+						const char *, ...);
+typedef const char *(*bpf_insn_revmap_call_t)(void *private_data,
+					      const struct bpf_insn *insn);
+typedef const char *(*bpf_insn_print_imm_t)(void *private_data,
+					    const struct bpf_insn *insn,
+					    __u64 full_imm);
+
+struct bpf_insn_cbs {
+	bpf_insn_print_t	cb_print;
+	bpf_insn_revmap_call_t	cb_call;
+	bpf_insn_print_imm_t	cb_imm;
+	void			*private_data;
+};
+
+void print_bpf_insn(const struct bpf_insn_cbs *cbs,
+		    const struct bpf_insn *insn,
+		    bool allow_ptr_leaks);
+#endif
diff --git a/kernel/bpf/dispatcher.c b/kernel/bpf/dispatcher.c
new file mode 100644
index 000000000..c19719f48
--- /dev/null
+++ b/kernel/bpf/dispatcher.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2019 Intel Corporation. */
+
+#include <linux/hash.h>
+#include <linux/bpf.h>
+#include <linux/filter.h>
+#include <linux/static_call.h>
+
+/* The BPF dispatcher is a multiway branch code generator. The
+ * dispatcher is a mechanism to avoid the performance penalty of an
+ * indirect call, which is expensive when retpolines are enabled. A
+ * dispatch client registers a BPF program into the dispatcher, and if
+ * there is available room in the dispatcher a direct call to the BPF
+ * program will be generated. All calls to the BPF programs called via
+ * the dispatcher will then be a direct call, instead of an
+ * indirect. The dispatcher hijacks a trampoline function it via the
+ * __fentry__ of the trampoline. The trampoline function has the
+ * following signature:
+ *
+ * unsigned int trampoline(const void *ctx, const struct bpf_insn *insnsi,
+ *                         unsigned int (*bpf_func)(const void *,
+ *                                                  const struct bpf_insn *));
+ */
+
+static struct bpf_dispatcher_prog *bpf_dispatcher_find_prog(
+	struct bpf_dispatcher *d, struct bpf_prog *prog)
+{
+	int i;
+
+	for (i = 0; i < BPF_DISPATCHER_MAX; i++) {
+		if (prog == d->progs[i].prog)
+			return &d->progs[i];
+	}
+	return NULL;
+}
+
+static struct bpf_dispatcher_prog *bpf_dispatcher_find_free(
+	struct bpf_dispatcher *d)
+{
+	return bpf_dispatcher_find_prog(d, NULL);
+}
+
+static bool bpf_dispatcher_add_prog(struct bpf_dispatcher *d,
+				    struct bpf_prog *prog)
+{
+	struct bpf_dispatcher_prog *entry;
+
+	if (!prog)
+		return false;
+
+	entry = bpf_dispatcher_find_prog(d, prog);
+	if (entry) {
+		refcount_inc(&entry->users);
+		return false;
+	}
+
+	entry = bpf_dispatcher_find_free(d);
+	if (!entry)
+		return false;
+
+	bpf_prog_inc(prog);
+	entry->prog = prog;
+	refcount_set(&entry->users, 1);
+	d->num_progs++;
+	return true;
+}
+
+static bool bpf_dispatcher_remove_prog(struct bpf_dispatcher *d,
+				       struct bpf_prog *prog)
+{
+	struct bpf_dispatcher_prog *entry;
+
+	if (!prog)
+		return false;
+
+	entry = bpf_dispatcher_find_prog(d, prog);
+	if (!entry)
+		return false;
+
+	if (refcount_dec_and_test(&entry->users)) {
+		entry->prog = NULL;
+		bpf_prog_put(prog);
+		d->num_progs--;
+		return true;
+	}
+	return false;
+}
+
+int __weak arch_prepare_bpf_dispatcher(void *image, void *buf, s64 *funcs, int num_funcs)
+{
+	return -ENOTSUPP;
+}
+
+static int bpf_dispatcher_prepare(struct bpf_dispatcher *d, void *image, void *buf)
+{
+	s64 ips[BPF_DISPATCHER_MAX] = {}, *ipsp = &ips[0];
+	int i;
+
+	for (i = 0; i < BPF_DISPATCHER_MAX; i++) {
+		if (d->progs[i].prog)
+			*ipsp++ = (s64)(uintptr_t)d->progs[i].prog->bpf_func;
+	}
+	return arch_prepare_bpf_dispatcher(image, buf, &ips[0], d->num_progs);
+}
+
+static void bpf_dispatcher_update(struct bpf_dispatcher *d, int prev_num_progs)
+{
+	void *new, *tmp;
+	u32 noff = 0;
+
+	if (prev_num_progs)
+		noff = d->image_off ^ (PAGE_SIZE / 2);
+
+	new = d->num_progs ? d->image + noff : NULL;
+	tmp = d->num_progs ? d->rw_image + noff : NULL;
+	if (new) {
+		/* Prepare the dispatcher in d->rw_image. Then use
+		 * bpf_arch_text_copy to update d->image, which is RO+X.
+		 */
+		if (bpf_dispatcher_prepare(d, new, tmp))
+			return;
+		if (IS_ERR(bpf_arch_text_copy(new, tmp, PAGE_SIZE / 2)))
+			return;
+	}
+
+	__BPF_DISPATCHER_UPDATE(d, new ?: (void *)&bpf_dispatcher_nop_func);
+
+	if (new)
+		d->image_off = noff;
+}
+
+void bpf_dispatcher_change_prog(struct bpf_dispatcher *d, struct bpf_prog *from,
+				struct bpf_prog *to)
+{
+	bool changed = false;
+	int prev_num_progs;
+
+	if (from == to)
+		return;
+
+	mutex_lock(&d->mutex);
+	if (!d->image) {
+		d->image = bpf_prog_pack_alloc(PAGE_SIZE, bpf_jit_fill_hole_with_zero);
+		if (!d->image)
+			goto out;
+		d->rw_image = bpf_jit_alloc_exec(PAGE_SIZE);
+		if (!d->rw_image) {
+			u32 size = PAGE_SIZE;
+
+			bpf_arch_text_copy(d->image, &size, sizeof(size));
+			bpf_prog_pack_free((struct bpf_binary_header *)d->image);
+			d->image = NULL;
+			goto out;
+		}
+		bpf_image_ksym_add(d->image, &d->ksym);
+	}
+
+	prev_num_progs = d->num_progs;
+	changed |= bpf_dispatcher_remove_prog(d, from);
+	changed |= bpf_dispatcher_add_prog(d, to);
+
+	if (!changed)
+		goto out;
+
+	bpf_dispatcher_update(d, prev_num_progs);
+out:
+	mutex_unlock(&d->mutex);
+}
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
new file mode 100644
index 000000000..88c71de0a
--- /dev/null
+++ b/kernel/bpf/hashtab.c
@@ -0,0 +1,2540 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ * Copyright (c) 2016 Facebook
+ */
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/jhash.h>
+#include <linux/filter.h>
+#include <linux/rculist_nulls.h>
+#include <linux/random.h>
+#include <uapi/linux/btf.h>
+#include <linux/rcupdate_trace.h>
+#include <linux/btf_ids.h>
+#include "percpu_freelist.h"
+#include "bpf_lru_list.h"
+#include "map_in_map.h"
+#include <linux/bpf_mem_alloc.h>
+
+#define HTAB_CREATE_FLAG_MASK						\
+	(BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE |	\
+	 BPF_F_ACCESS_MASK | BPF_F_ZERO_SEED)
+
+#define BATCH_OPS(_name)			\
+	.map_lookup_batch =			\
+	_name##_map_lookup_batch,		\
+	.map_lookup_and_delete_batch =		\
+	_name##_map_lookup_and_delete_batch,	\
+	.map_update_batch =			\
+	generic_map_update_batch,		\
+	.map_delete_batch =			\
+	generic_map_delete_batch
+
+/*
+ * The bucket lock has two protection scopes:
+ *
+ * 1) Serializing concurrent operations from BPF programs on different
+ *    CPUs
+ *
+ * 2) Serializing concurrent operations from BPF programs and sys_bpf()
+ *
+ * BPF programs can execute in any context including perf, kprobes and
+ * tracing. As there are almost no limits where perf, kprobes and tracing
+ * can be invoked from the lock operations need to be protected against
+ * deadlocks. Deadlocks can be caused by recursion and by an invocation in
+ * the lock held section when functions which acquire this lock are invoked
+ * from sys_bpf(). BPF recursion is prevented by incrementing the per CPU
+ * variable bpf_prog_active, which prevents BPF programs attached to perf
+ * events, kprobes and tracing to be invoked before the prior invocation
+ * from one of these contexts completed. sys_bpf() uses the same mechanism
+ * by pinning the task to the current CPU and incrementing the recursion
+ * protection across the map operation.
+ *
+ * This has subtle implications on PREEMPT_RT. PREEMPT_RT forbids certain
+ * operations like memory allocations (even with GFP_ATOMIC) from atomic
+ * contexts. This is required because even with GFP_ATOMIC the memory
+ * allocator calls into code paths which acquire locks with long held lock
+ * sections. To ensure the deterministic behaviour these locks are regular
+ * spinlocks, which are converted to 'sleepable' spinlocks on RT. The only
+ * true atomic contexts on an RT kernel are the low level hardware
+ * handling, scheduling, low level interrupt handling, NMIs etc. None of
+ * these contexts should ever do memory allocations.
+ *
+ * As regular device interrupt handlers and soft interrupts are forced into
+ * thread context, the existing code which does
+ *   spin_lock*(); alloc(GFP_ATOMIC); spin_unlock*();
+ * just works.
+ *
+ * In theory the BPF locks could be converted to regular spinlocks as well,
+ * but the bucket locks and percpu_freelist locks can be taken from
+ * arbitrary contexts (perf, kprobes, tracepoints) which are required to be
+ * atomic contexts even on RT. Before the introduction of bpf_mem_alloc,
+ * it is only safe to use raw spinlock for preallocated hash map on a RT kernel,
+ * because there is no memory allocation within the lock held sections. However
+ * after hash map was fully converted to use bpf_mem_alloc, there will be
+ * non-synchronous memory allocation for non-preallocated hash map, so it is
+ * safe to always use raw spinlock for bucket lock.
+ */
+struct bucket {
+	struct hlist_nulls_head head;
+	raw_spinlock_t raw_lock;
+};
+
+#define HASHTAB_MAP_LOCK_COUNT 8
+#define HASHTAB_MAP_LOCK_MASK (HASHTAB_MAP_LOCK_COUNT - 1)
+
+struct bpf_htab {
+	struct bpf_map map;
+	struct bpf_mem_alloc ma;
+	struct bpf_mem_alloc pcpu_ma;
+	struct bucket *buckets;
+	void *elems;
+	union {
+		struct pcpu_freelist freelist;
+		struct bpf_lru lru;
+	};
+	struct htab_elem *__percpu *extra_elems;
+	/* number of elements in non-preallocated hashtable are kept
+	 * in either pcount or count
+	 */
+	struct percpu_counter pcount;
+	atomic_t count;
+	bool use_percpu_counter;
+	u32 n_buckets;	/* number of hash buckets */
+	u32 elem_size;	/* size of each element in bytes */
+	u32 hashrnd;
+	struct lock_class_key lockdep_key;
+	int __percpu *map_locked[HASHTAB_MAP_LOCK_COUNT];
+};
+
+/* each htab element is struct htab_elem + key + value */
+struct htab_elem {
+	union {
+		struct hlist_nulls_node hash_node;
+		struct {
+			void *padding;
+			union {
+				struct pcpu_freelist_node fnode;
+				struct htab_elem *batch_flink;
+			};
+		};
+	};
+	union {
+		/* pointer to per-cpu pointer */
+		void *ptr_to_pptr;
+		struct bpf_lru_node lru_node;
+	};
+	u32 hash;
+	char key[] __aligned(8);
+};
+
+static inline bool htab_is_prealloc(const struct bpf_htab *htab)
+{
+	return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
+}
+
+static void htab_init_buckets(struct bpf_htab *htab)
+{
+	unsigned int i;
+
+	for (i = 0; i < htab->n_buckets; i++) {
+		INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
+		raw_spin_lock_init(&htab->buckets[i].raw_lock);
+		lockdep_set_class(&htab->buckets[i].raw_lock,
+					  &htab->lockdep_key);
+		cond_resched();
+	}
+}
+
+static inline int htab_lock_bucket(const struct bpf_htab *htab,
+				   struct bucket *b, u32 hash,
+				   unsigned long *pflags)
+{
+	unsigned long flags;
+
+	hash = hash & min_t(u32, HASHTAB_MAP_LOCK_MASK, htab->n_buckets - 1);
+
+	preempt_disable();
+	local_irq_save(flags);
+	if (unlikely(__this_cpu_inc_return(*(htab->map_locked[hash])) != 1)) {
+		__this_cpu_dec(*(htab->map_locked[hash]));
+		local_irq_restore(flags);
+		preempt_enable();
+		return -EBUSY;
+	}
+
+	raw_spin_lock(&b->raw_lock);
+	*pflags = flags;
+
+	return 0;
+}
+
+static inline void htab_unlock_bucket(const struct bpf_htab *htab,
+				      struct bucket *b, u32 hash,
+				      unsigned long flags)
+{
+	hash = hash & min_t(u32, HASHTAB_MAP_LOCK_MASK, htab->n_buckets - 1);
+	raw_spin_unlock(&b->raw_lock);
+	__this_cpu_dec(*(htab->map_locked[hash]));
+	local_irq_restore(flags);
+	preempt_enable();
+}
+
+static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
+
+static bool htab_is_lru(const struct bpf_htab *htab)
+{
+	return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
+		htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
+}
+
+static bool htab_is_percpu(const struct bpf_htab *htab)
+{
+	return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+		htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
+}
+
+static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
+				     void __percpu *pptr)
+{
+	*(void __percpu **)(l->key + key_size) = pptr;
+}
+
+static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
+{
+	return *(void __percpu **)(l->key + key_size);
+}
+
+static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
+{
+	return *(void **)(l->key + roundup(map->key_size, 8));
+}
+
+static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
+{
+	return (struct htab_elem *) (htab->elems + i * (u64)htab->elem_size);
+}
+
+static bool htab_has_extra_elems(struct bpf_htab *htab)
+{
+	return !htab_is_percpu(htab) && !htab_is_lru(htab);
+}
+
+static void htab_free_prealloced_timers(struct bpf_htab *htab)
+{
+	u32 num_entries = htab->map.max_entries;
+	int i;
+
+	if (!map_value_has_timer(&htab->map))
+		return;
+	if (htab_has_extra_elems(htab))
+		num_entries += num_possible_cpus();
+
+	for (i = 0; i < num_entries; i++) {
+		struct htab_elem *elem;
+
+		elem = get_htab_elem(htab, i);
+		bpf_timer_cancel_and_free(elem->key +
+					  round_up(htab->map.key_size, 8) +
+					  htab->map.timer_off);
+		cond_resched();
+	}
+}
+
+static void htab_free_prealloced_kptrs(struct bpf_htab *htab)
+{
+	u32 num_entries = htab->map.max_entries;
+	int i;
+
+	if (!map_value_has_kptrs(&htab->map))
+		return;
+	if (htab_has_extra_elems(htab))
+		num_entries += num_possible_cpus();
+
+	for (i = 0; i < num_entries; i++) {
+		struct htab_elem *elem;
+
+		elem = get_htab_elem(htab, i);
+		bpf_map_free_kptrs(&htab->map, elem->key + round_up(htab->map.key_size, 8));
+		cond_resched();
+	}
+}
+
+static void htab_free_elems(struct bpf_htab *htab)
+{
+	int i;
+
+	if (!htab_is_percpu(htab))
+		goto free_elems;
+
+	for (i = 0; i < htab->map.max_entries; i++) {
+		void __percpu *pptr;
+
+		pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
+					 htab->map.key_size);
+		free_percpu(pptr);
+		cond_resched();
+	}
+free_elems:
+	bpf_map_area_free(htab->elems);
+}
+
+/* The LRU list has a lock (lru_lock). Each htab bucket has a lock
+ * (bucket_lock). If both locks need to be acquired together, the lock
+ * order is always lru_lock -> bucket_lock and this only happens in
+ * bpf_lru_list.c logic. For example, certain code path of
+ * bpf_lru_pop_free(), which is called by function prealloc_lru_pop(),
+ * will acquire lru_lock first followed by acquiring bucket_lock.
+ *
+ * In hashtab.c, to avoid deadlock, lock acquisition of
+ * bucket_lock followed by lru_lock is not allowed. In such cases,
+ * bucket_lock needs to be released first before acquiring lru_lock.
+ */
+static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
+					  u32 hash)
+{
+	struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
+	struct htab_elem *l;
+
+	if (node) {
+		l = container_of(node, struct htab_elem, lru_node);
+		memcpy(l->key, key, htab->map.key_size);
+		return l;
+	}
+
+	return NULL;
+}
+
+static int prealloc_init(struct bpf_htab *htab)
+{
+	u32 num_entries = htab->map.max_entries;
+	int err = -ENOMEM, i;
+
+	if (htab_has_extra_elems(htab))
+		num_entries += num_possible_cpus();
+
+	htab->elems = bpf_map_area_alloc((u64)htab->elem_size * num_entries,
+					 htab->map.numa_node);
+	if (!htab->elems)
+		return -ENOMEM;
+
+	if (!htab_is_percpu(htab))
+		goto skip_percpu_elems;
+
+	for (i = 0; i < num_entries; i++) {
+		u32 size = round_up(htab->map.value_size, 8);
+		void __percpu *pptr;
+
+		pptr = bpf_map_alloc_percpu(&htab->map, size, 8,
+					    GFP_USER | __GFP_NOWARN);
+		if (!pptr)
+			goto free_elems;
+		htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
+				  pptr);
+		cond_resched();
+	}
+
+skip_percpu_elems:
+	if (htab_is_lru(htab))
+		err = bpf_lru_init(&htab->lru,
+				   htab->map.map_flags & BPF_F_NO_COMMON_LRU,
+				   offsetof(struct htab_elem, hash) -
+				   offsetof(struct htab_elem, lru_node),
+				   htab_lru_map_delete_node,
+				   htab);
+	else
+		err = pcpu_freelist_init(&htab->freelist);
+
+	if (err)
+		goto free_elems;
+
+	if (htab_is_lru(htab))
+		bpf_lru_populate(&htab->lru, htab->elems,
+				 offsetof(struct htab_elem, lru_node),
+				 htab->elem_size, num_entries);
+	else
+		pcpu_freelist_populate(&htab->freelist,
+				       htab->elems + offsetof(struct htab_elem, fnode),
+				       htab->elem_size, num_entries);
+
+	return 0;
+
+free_elems:
+	htab_free_elems(htab);
+	return err;
+}
+
+static void prealloc_destroy(struct bpf_htab *htab)
+{
+	htab_free_elems(htab);
+
+	if (htab_is_lru(htab))
+		bpf_lru_destroy(&htab->lru);
+	else
+		pcpu_freelist_destroy(&htab->freelist);
+}
+
+static int alloc_extra_elems(struct bpf_htab *htab)
+{
+	struct htab_elem *__percpu *pptr, *l_new;
+	struct pcpu_freelist_node *l;
+	int cpu;
+
+	pptr = bpf_map_alloc_percpu(&htab->map, sizeof(struct htab_elem *), 8,
+				    GFP_USER | __GFP_NOWARN);
+	if (!pptr)
+		return -ENOMEM;
+
+	for_each_possible_cpu(cpu) {
+		l = pcpu_freelist_pop(&htab->freelist);
+		/* pop will succeed, since prealloc_init()
+		 * preallocated extra num_possible_cpus elements
+		 */
+		l_new = container_of(l, struct htab_elem, fnode);
+		*per_cpu_ptr(pptr, cpu) = l_new;
+	}
+	htab->extra_elems = pptr;
+	return 0;
+}
+
+/* Called from syscall */
+static int htab_map_alloc_check(union bpf_attr *attr)
+{
+	bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+		       attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
+	bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
+		    attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
+	/* percpu_lru means each cpu has its own LRU list.
+	 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
+	 * the map's value itself is percpu.  percpu_lru has
+	 * nothing to do with the map's value.
+	 */
+	bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
+	bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
+	bool zero_seed = (attr->map_flags & BPF_F_ZERO_SEED);
+	int numa_node = bpf_map_attr_numa_node(attr);
+
+	BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
+		     offsetof(struct htab_elem, hash_node.pprev));
+
+	if (lru && !bpf_capable())
+		/* LRU implementation is much complicated than other
+		 * maps.  Hence, limit to CAP_BPF.
+		 */
+		return -EPERM;
+
+	if (zero_seed && !capable(CAP_SYS_ADMIN))
+		/* Guard against local DoS, and discourage production use. */
+		return -EPERM;
+
+	if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK ||
+	    !bpf_map_flags_access_ok(attr->map_flags))
+		return -EINVAL;
+
+	if (!lru && percpu_lru)
+		return -EINVAL;
+
+	if (lru && !prealloc)
+		return -ENOTSUPP;
+
+	if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
+		return -EINVAL;
+
+	/* check sanity of attributes.
+	 * value_size == 0 may be allowed in the future to use map as a set
+	 */
+	if (attr->max_entries == 0 || attr->key_size == 0 ||
+	    attr->value_size == 0)
+		return -EINVAL;
+
+	if ((u64)attr->key_size + attr->value_size >= KMALLOC_MAX_SIZE -
+	   sizeof(struct htab_elem))
+		/* if key_size + value_size is bigger, the user space won't be
+		 * able to access the elements via bpf syscall. This check
+		 * also makes sure that the elem_size doesn't overflow and it's
+		 * kmalloc-able later in htab_map_update_elem()
+		 */
+		return -E2BIG;
+
+	return 0;
+}
+
+static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
+{
+	bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+		       attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
+	bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
+		    attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
+	/* percpu_lru means each cpu has its own LRU list.
+	 * it is different from BPF_MAP_TYPE_PERCPU_HASH where
+	 * the map's value itself is percpu.  percpu_lru has
+	 * nothing to do with the map's value.
+	 */
+	bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
+	bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
+	struct bpf_htab *htab;
+	int err, i;
+
+	htab = bpf_map_area_alloc(sizeof(*htab), NUMA_NO_NODE);
+	if (!htab)
+		return ERR_PTR(-ENOMEM);
+
+	lockdep_register_key(&htab->lockdep_key);
+
+	bpf_map_init_from_attr(&htab->map, attr);
+
+	if (percpu_lru) {
+		/* ensure each CPU's lru list has >=1 elements.
+		 * since we are at it, make each lru list has the same
+		 * number of elements.
+		 */
+		htab->map.max_entries = roundup(attr->max_entries,
+						num_possible_cpus());
+		if (htab->map.max_entries < attr->max_entries)
+			htab->map.max_entries = rounddown(attr->max_entries,
+							  num_possible_cpus());
+	}
+
+	/* hash table size must be power of 2 */
+	htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
+
+	htab->elem_size = sizeof(struct htab_elem) +
+			  round_up(htab->map.key_size, 8);
+	if (percpu)
+		htab->elem_size += sizeof(void *);
+	else
+		htab->elem_size += round_up(htab->map.value_size, 8);
+
+	err = -E2BIG;
+	/* prevent zero size kmalloc and check for u32 overflow */
+	if (htab->n_buckets == 0 ||
+	    htab->n_buckets > U32_MAX / sizeof(struct bucket))
+		goto free_htab;
+
+	err = -ENOMEM;
+	htab->buckets = bpf_map_area_alloc(htab->n_buckets *
+					   sizeof(struct bucket),
+					   htab->map.numa_node);
+	if (!htab->buckets)
+		goto free_htab;
+
+	for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) {
+		htab->map_locked[i] = bpf_map_alloc_percpu(&htab->map,
+							   sizeof(int),
+							   sizeof(int),
+							   GFP_USER);
+		if (!htab->map_locked[i])
+			goto free_map_locked;
+	}
+
+	if (htab->map.map_flags & BPF_F_ZERO_SEED)
+		htab->hashrnd = 0;
+	else
+		htab->hashrnd = get_random_u32();
+
+	htab_init_buckets(htab);
+
+/* compute_batch_value() computes batch value as num_online_cpus() * 2
+ * and __percpu_counter_compare() needs
+ * htab->max_entries - cur_number_of_elems to be more than batch * num_online_cpus()
+ * for percpu_counter to be faster than atomic_t. In practice the average bpf
+ * hash map size is 10k, which means that a system with 64 cpus will fill
+ * hashmap to 20% of 10k before percpu_counter becomes ineffective. Therefore
+ * define our own batch count as 32 then 10k hash map can be filled up to 80%:
+ * 10k - 8k > 32 _batch_ * 64 _cpus_
+ * and __percpu_counter_compare() will still be fast. At that point hash map
+ * collisions will dominate its performance anyway. Assume that hash map filled
+ * to 50+% isn't going to be O(1) and use the following formula to choose
+ * between percpu_counter and atomic_t.
+ */
+#define PERCPU_COUNTER_BATCH 32
+	if (attr->max_entries / 2 > num_online_cpus() * PERCPU_COUNTER_BATCH)
+		htab->use_percpu_counter = true;
+
+	if (htab->use_percpu_counter) {
+		err = percpu_counter_init(&htab->pcount, 0, GFP_KERNEL);
+		if (err)
+			goto free_map_locked;
+	}
+
+	if (prealloc) {
+		err = prealloc_init(htab);
+		if (err)
+			goto free_map_locked;
+
+		if (!percpu && !lru) {
+			/* lru itself can remove the least used element, so
+			 * there is no need for an extra elem during map_update.
+			 */
+			err = alloc_extra_elems(htab);
+			if (err)
+				goto free_prealloc;
+		}
+	} else {
+		err = bpf_mem_alloc_init(&htab->ma, htab->elem_size, false);
+		if (err)
+			goto free_map_locked;
+		if (percpu) {
+			err = bpf_mem_alloc_init(&htab->pcpu_ma,
+						 round_up(htab->map.value_size, 8), true);
+			if (err)
+				goto free_map_locked;
+		}
+	}
+
+	return &htab->map;
+
+free_prealloc:
+	prealloc_destroy(htab);
+free_map_locked:
+	if (htab->use_percpu_counter)
+		percpu_counter_destroy(&htab->pcount);
+	for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
+		free_percpu(htab->map_locked[i]);
+	bpf_map_area_free(htab->buckets);
+	bpf_mem_alloc_destroy(&htab->pcpu_ma);
+	bpf_mem_alloc_destroy(&htab->ma);
+free_htab:
+	lockdep_unregister_key(&htab->lockdep_key);
+	bpf_map_area_free(htab);
+	return ERR_PTR(err);
+}
+
+static inline u32 htab_map_hash(const void *key, u32 key_len, u32 hashrnd)
+{
+	return jhash(key, key_len, hashrnd);
+}
+
+static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
+{
+	return &htab->buckets[hash & (htab->n_buckets - 1)];
+}
+
+static inline struct hlist_nulls_head *select_bucket(struct bpf_htab *htab, u32 hash)
+{
+	return &__select_bucket(htab, hash)->head;
+}
+
+/* this lookup function can only be called with bucket lock taken */
+static struct htab_elem *lookup_elem_raw(struct hlist_nulls_head *head, u32 hash,
+					 void *key, u32 key_size)
+{
+	struct hlist_nulls_node *n;
+	struct htab_elem *l;
+
+	hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
+		if (l->hash == hash && !memcmp(&l->key, key, key_size))
+			return l;
+
+	return NULL;
+}
+
+/* can be called without bucket lock. it will repeat the loop in
+ * the unlikely event when elements moved from one bucket into another
+ * while link list is being walked
+ */
+static struct htab_elem *lookup_nulls_elem_raw(struct hlist_nulls_head *head,
+					       u32 hash, void *key,
+					       u32 key_size, u32 n_buckets)
+{
+	struct hlist_nulls_node *n;
+	struct htab_elem *l;
+
+again:
+	hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
+		if (l->hash == hash && !memcmp(&l->key, key, key_size))
+			return l;
+
+	if (unlikely(get_nulls_value(n) != (hash & (n_buckets - 1))))
+		goto again;
+
+	return NULL;
+}
+
+/* Called from syscall or from eBPF program directly, so
+ * arguments have to match bpf_map_lookup_elem() exactly.
+ * The return value is adjusted by BPF instructions
+ * in htab_map_gen_lookup().
+ */
+static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct hlist_nulls_head *head;
+	struct htab_elem *l;
+	u32 hash, key_size;
+
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+		     !rcu_read_lock_bh_held());
+
+	key_size = map->key_size;
+
+	hash = htab_map_hash(key, key_size, htab->hashrnd);
+
+	head = select_bucket(htab, hash);
+
+	l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
+
+	return l;
+}
+
+static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct htab_elem *l = __htab_map_lookup_elem(map, key);
+
+	if (l)
+		return l->key + round_up(map->key_size, 8);
+
+	return NULL;
+}
+
+/* inline bpf_map_lookup_elem() call.
+ * Instead of:
+ * bpf_prog
+ *   bpf_map_lookup_elem
+ *     map->ops->map_lookup_elem
+ *       htab_map_lookup_elem
+ *         __htab_map_lookup_elem
+ * do:
+ * bpf_prog
+ *   __htab_map_lookup_elem
+ */
+static int htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
+{
+	struct bpf_insn *insn = insn_buf;
+	const int ret = BPF_REG_0;
+
+	BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
+		     (void *(*)(struct bpf_map *map, void *key))NULL));
+	*insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
+	*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
+	*insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
+				offsetof(struct htab_elem, key) +
+				round_up(map->key_size, 8));
+	return insn - insn_buf;
+}
+
+static __always_inline void *__htab_lru_map_lookup_elem(struct bpf_map *map,
+							void *key, const bool mark)
+{
+	struct htab_elem *l = __htab_map_lookup_elem(map, key);
+
+	if (l) {
+		if (mark)
+			bpf_lru_node_set_ref(&l->lru_node);
+		return l->key + round_up(map->key_size, 8);
+	}
+
+	return NULL;
+}
+
+static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	return __htab_lru_map_lookup_elem(map, key, true);
+}
+
+static void *htab_lru_map_lookup_elem_sys(struct bpf_map *map, void *key)
+{
+	return __htab_lru_map_lookup_elem(map, key, false);
+}
+
+static int htab_lru_map_gen_lookup(struct bpf_map *map,
+				   struct bpf_insn *insn_buf)
+{
+	struct bpf_insn *insn = insn_buf;
+	const int ret = BPF_REG_0;
+	const int ref_reg = BPF_REG_1;
+
+	BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
+		     (void *(*)(struct bpf_map *map, void *key))NULL));
+	*insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
+	*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4);
+	*insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret,
+			      offsetof(struct htab_elem, lru_node) +
+			      offsetof(struct bpf_lru_node, ref));
+	*insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1);
+	*insn++ = BPF_ST_MEM(BPF_B, ret,
+			     offsetof(struct htab_elem, lru_node) +
+			     offsetof(struct bpf_lru_node, ref),
+			     1);
+	*insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
+				offsetof(struct htab_elem, key) +
+				round_up(map->key_size, 8));
+	return insn - insn_buf;
+}
+
+static void check_and_free_fields(struct bpf_htab *htab,
+				  struct htab_elem *elem)
+{
+	void *map_value = elem->key + round_up(htab->map.key_size, 8);
+
+	if (map_value_has_timer(&htab->map))
+		bpf_timer_cancel_and_free(map_value + htab->map.timer_off);
+	if (map_value_has_kptrs(&htab->map))
+		bpf_map_free_kptrs(&htab->map, map_value);
+}
+
+/* It is called from the bpf_lru_list when the LRU needs to delete
+ * older elements from the htab.
+ */
+static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
+{
+	struct bpf_htab *htab = arg;
+	struct htab_elem *l = NULL, *tgt_l;
+	struct hlist_nulls_head *head;
+	struct hlist_nulls_node *n;
+	unsigned long flags;
+	struct bucket *b;
+	int ret;
+
+	tgt_l = container_of(node, struct htab_elem, lru_node);
+	b = __select_bucket(htab, tgt_l->hash);
+	head = &b->head;
+
+	ret = htab_lock_bucket(htab, b, tgt_l->hash, &flags);
+	if (ret)
+		return false;
+
+	hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
+		if (l == tgt_l) {
+			hlist_nulls_del_rcu(&l->hash_node);
+			check_and_free_fields(htab, l);
+			break;
+		}
+
+	htab_unlock_bucket(htab, b, tgt_l->hash, flags);
+
+	return l == tgt_l;
+}
+
+/* Called from syscall */
+static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct hlist_nulls_head *head;
+	struct htab_elem *l, *next_l;
+	u32 hash, key_size;
+	int i = 0;
+
+	WARN_ON_ONCE(!rcu_read_lock_held());
+
+	key_size = map->key_size;
+
+	if (!key)
+		goto find_first_elem;
+
+	hash = htab_map_hash(key, key_size, htab->hashrnd);
+
+	head = select_bucket(htab, hash);
+
+	/* lookup the key */
+	l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
+
+	if (!l)
+		goto find_first_elem;
+
+	/* key was found, get next key in the same bucket */
+	next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_next_rcu(&l->hash_node)),
+				  struct htab_elem, hash_node);
+
+	if (next_l) {
+		/* if next elem in this hash list is non-zero, just return it */
+		memcpy(next_key, next_l->key, key_size);
+		return 0;
+	}
+
+	/* no more elements in this hash list, go to the next bucket */
+	i = hash & (htab->n_buckets - 1);
+	i++;
+
+find_first_elem:
+	/* iterate over buckets */
+	for (; i < htab->n_buckets; i++) {
+		head = select_bucket(htab, i);
+
+		/* pick first element in the bucket */
+		next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_first_rcu(head)),
+					  struct htab_elem, hash_node);
+		if (next_l) {
+			/* if it's not empty, just return it */
+			memcpy(next_key, next_l->key, key_size);
+			return 0;
+		}
+	}
+
+	/* iterated over all buckets and all elements */
+	return -ENOENT;
+}
+
+static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
+{
+	if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
+		bpf_mem_cache_free(&htab->pcpu_ma, l->ptr_to_pptr);
+	check_and_free_fields(htab, l);
+	bpf_mem_cache_free(&htab->ma, l);
+}
+
+static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
+{
+	struct bpf_map *map = &htab->map;
+	void *ptr;
+
+	if (map->ops->map_fd_put_ptr) {
+		ptr = fd_htab_map_get_ptr(map, l);
+		map->ops->map_fd_put_ptr(map, ptr, true);
+	}
+}
+
+static bool is_map_full(struct bpf_htab *htab)
+{
+	if (htab->use_percpu_counter)
+		return __percpu_counter_compare(&htab->pcount, htab->map.max_entries,
+						PERCPU_COUNTER_BATCH) >= 0;
+	return atomic_read(&htab->count) >= htab->map.max_entries;
+}
+
+static void inc_elem_count(struct bpf_htab *htab)
+{
+	if (htab->use_percpu_counter)
+		percpu_counter_add_batch(&htab->pcount, 1, PERCPU_COUNTER_BATCH);
+	else
+		atomic_inc(&htab->count);
+}
+
+static void dec_elem_count(struct bpf_htab *htab)
+{
+	if (htab->use_percpu_counter)
+		percpu_counter_add_batch(&htab->pcount, -1, PERCPU_COUNTER_BATCH);
+	else
+		atomic_dec(&htab->count);
+}
+
+
+static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
+{
+	htab_put_fd_value(htab, l);
+
+	if (htab_is_prealloc(htab)) {
+		check_and_free_fields(htab, l);
+		__pcpu_freelist_push(&htab->freelist, &l->fnode);
+	} else {
+		dec_elem_count(htab);
+		htab_elem_free(htab, l);
+	}
+}
+
+static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
+			    void *value, bool onallcpus)
+{
+	if (!onallcpus) {
+		/* copy true value_size bytes */
+		memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);
+	} else {
+		u32 size = round_up(htab->map.value_size, 8);
+		int off = 0, cpu;
+
+		for_each_possible_cpu(cpu) {
+			bpf_long_memcpy(per_cpu_ptr(pptr, cpu),
+					value + off, size);
+			off += size;
+		}
+	}
+}
+
+static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr,
+			    void *value, bool onallcpus)
+{
+	/* When not setting the initial value on all cpus, zero-fill element
+	 * values for other cpus. Otherwise, bpf program has no way to ensure
+	 * known initial values for cpus other than current one
+	 * (onallcpus=false always when coming from bpf prog).
+	 */
+	if (!onallcpus) {
+		u32 size = round_up(htab->map.value_size, 8);
+		int current_cpu = raw_smp_processor_id();
+		int cpu;
+
+		for_each_possible_cpu(cpu) {
+			if (cpu == current_cpu)
+				bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value,
+						size);
+			else
+				memset(per_cpu_ptr(pptr, cpu), 0, size);
+		}
+	} else {
+		pcpu_copy_value(htab, pptr, value, onallcpus);
+	}
+}
+
+static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
+{
+	return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
+	       BITS_PER_LONG == 64;
+}
+
+static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
+					 void *value, u32 key_size, u32 hash,
+					 bool percpu, bool onallcpus,
+					 struct htab_elem *old_elem)
+{
+	u32 size = htab->map.value_size;
+	bool prealloc = htab_is_prealloc(htab);
+	struct htab_elem *l_new, **pl_new;
+	void __percpu *pptr;
+
+	if (prealloc) {
+		if (old_elem) {
+			/* if we're updating the existing element,
+			 * use per-cpu extra elems to avoid freelist_pop/push
+			 */
+			pl_new = this_cpu_ptr(htab->extra_elems);
+			l_new = *pl_new;
+			htab_put_fd_value(htab, old_elem);
+			*pl_new = old_elem;
+		} else {
+			struct pcpu_freelist_node *l;
+
+			l = __pcpu_freelist_pop(&htab->freelist);
+			if (!l)
+				return ERR_PTR(-E2BIG);
+			l_new = container_of(l, struct htab_elem, fnode);
+		}
+	} else {
+		if (is_map_full(htab))
+			if (!old_elem)
+				/* when map is full and update() is replacing
+				 * old element, it's ok to allocate, since
+				 * old element will be freed immediately.
+				 * Otherwise return an error
+				 */
+				return ERR_PTR(-E2BIG);
+		inc_elem_count(htab);
+		l_new = bpf_mem_cache_alloc(&htab->ma);
+		if (!l_new) {
+			l_new = ERR_PTR(-ENOMEM);
+			goto dec_count;
+		}
+	}
+
+	memcpy(l_new->key, key, key_size);
+	if (percpu) {
+		if (prealloc) {
+			pptr = htab_elem_get_ptr(l_new, key_size);
+		} else {
+			/* alloc_percpu zero-fills */
+			pptr = bpf_mem_cache_alloc(&htab->pcpu_ma);
+			if (!pptr) {
+				bpf_mem_cache_free(&htab->ma, l_new);
+				l_new = ERR_PTR(-ENOMEM);
+				goto dec_count;
+			}
+			l_new->ptr_to_pptr = pptr;
+			pptr = *(void **)pptr;
+		}
+
+		pcpu_init_value(htab, pptr, value, onallcpus);
+
+		if (!prealloc)
+			htab_elem_set_ptr(l_new, key_size, pptr);
+	} else if (fd_htab_map_needs_adjust(htab)) {
+		size = round_up(size, 8);
+		memcpy(l_new->key + round_up(key_size, 8), value, size);
+	} else {
+		copy_map_value(&htab->map,
+			       l_new->key + round_up(key_size, 8),
+			       value);
+	}
+
+	l_new->hash = hash;
+	return l_new;
+dec_count:
+	dec_elem_count(htab);
+	return l_new;
+}
+
+static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
+		       u64 map_flags)
+{
+	if (l_old && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
+		/* elem already exists */
+		return -EEXIST;
+
+	if (!l_old && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
+		/* elem doesn't exist, cannot update it */
+		return -ENOENT;
+
+	return 0;
+}
+
+/* Called from syscall or from eBPF program */
+static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
+				u64 map_flags)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct htab_elem *l_new = NULL, *l_old;
+	struct hlist_nulls_head *head;
+	unsigned long flags;
+	struct bucket *b;
+	u32 key_size, hash;
+	int ret;
+
+	if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
+		/* unknown flags */
+		return -EINVAL;
+
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+		     !rcu_read_lock_bh_held());
+
+	key_size = map->key_size;
+
+	hash = htab_map_hash(key, key_size, htab->hashrnd);
+
+	b = __select_bucket(htab, hash);
+	head = &b->head;
+
+	if (unlikely(map_flags & BPF_F_LOCK)) {
+		if (unlikely(!map_value_has_spin_lock(map)))
+			return -EINVAL;
+		/* find an element without taking the bucket lock */
+		l_old = lookup_nulls_elem_raw(head, hash, key, key_size,
+					      htab->n_buckets);
+		ret = check_flags(htab, l_old, map_flags);
+		if (ret)
+			return ret;
+		if (l_old) {
+			/* grab the element lock and update value in place */
+			copy_map_value_locked(map,
+					      l_old->key + round_up(key_size, 8),
+					      value, false);
+			return 0;
+		}
+		/* fall through, grab the bucket lock and lookup again.
+		 * 99.9% chance that the element won't be found,
+		 * but second lookup under lock has to be done.
+		 */
+	}
+
+	ret = htab_lock_bucket(htab, b, hash, &flags);
+	if (ret)
+		return ret;
+
+	l_old = lookup_elem_raw(head, hash, key, key_size);
+
+	ret = check_flags(htab, l_old, map_flags);
+	if (ret)
+		goto err;
+
+	if (unlikely(l_old && (map_flags & BPF_F_LOCK))) {
+		/* first lookup without the bucket lock didn't find the element,
+		 * but second lookup with the bucket lock found it.
+		 * This case is highly unlikely, but has to be dealt with:
+		 * grab the element lock in addition to the bucket lock
+		 * and update element in place
+		 */
+		copy_map_value_locked(map,
+				      l_old->key + round_up(key_size, 8),
+				      value, false);
+		ret = 0;
+		goto err;
+	}
+
+	l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
+				l_old);
+	if (IS_ERR(l_new)) {
+		/* all pre-allocated elements are in use or memory exhausted */
+		ret = PTR_ERR(l_new);
+		goto err;
+	}
+
+	/* add new element to the head of the list, so that
+	 * concurrent search will find it before old elem
+	 */
+	hlist_nulls_add_head_rcu(&l_new->hash_node, head);
+	if (l_old) {
+		hlist_nulls_del_rcu(&l_old->hash_node);
+		if (!htab_is_prealloc(htab))
+			free_htab_elem(htab, l_old);
+		else
+			check_and_free_fields(htab, l_old);
+	}
+	ret = 0;
+err:
+	htab_unlock_bucket(htab, b, hash, flags);
+	return ret;
+}
+
+static void htab_lru_push_free(struct bpf_htab *htab, struct htab_elem *elem)
+{
+	check_and_free_fields(htab, elem);
+	bpf_lru_push_free(&htab->lru, &elem->lru_node);
+}
+
+static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
+				    u64 map_flags)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct htab_elem *l_new, *l_old = NULL;
+	struct hlist_nulls_head *head;
+	unsigned long flags;
+	struct bucket *b;
+	u32 key_size, hash;
+	int ret;
+
+	if (unlikely(map_flags > BPF_EXIST))
+		/* unknown flags */
+		return -EINVAL;
+
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+		     !rcu_read_lock_bh_held());
+
+	key_size = map->key_size;
+
+	hash = htab_map_hash(key, key_size, htab->hashrnd);
+
+	b = __select_bucket(htab, hash);
+	head = &b->head;
+
+	/* For LRU, we need to alloc before taking bucket's
+	 * spinlock because getting free nodes from LRU may need
+	 * to remove older elements from htab and this removal
+	 * operation will need a bucket lock.
+	 */
+	l_new = prealloc_lru_pop(htab, key, hash);
+	if (!l_new)
+		return -ENOMEM;
+	copy_map_value(&htab->map,
+		       l_new->key + round_up(map->key_size, 8), value);
+
+	ret = htab_lock_bucket(htab, b, hash, &flags);
+	if (ret)
+		goto err_lock_bucket;
+
+	l_old = lookup_elem_raw(head, hash, key, key_size);
+
+	ret = check_flags(htab, l_old, map_flags);
+	if (ret)
+		goto err;
+
+	/* add new element to the head of the list, so that
+	 * concurrent search will find it before old elem
+	 */
+	hlist_nulls_add_head_rcu(&l_new->hash_node, head);
+	if (l_old) {
+		bpf_lru_node_set_ref(&l_new->lru_node);
+		hlist_nulls_del_rcu(&l_old->hash_node);
+	}
+	ret = 0;
+
+err:
+	htab_unlock_bucket(htab, b, hash, flags);
+
+err_lock_bucket:
+	if (ret)
+		htab_lru_push_free(htab, l_new);
+	else if (l_old)
+		htab_lru_push_free(htab, l_old);
+
+	return ret;
+}
+
+static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
+					 void *value, u64 map_flags,
+					 bool onallcpus)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct htab_elem *l_new = NULL, *l_old;
+	struct hlist_nulls_head *head;
+	unsigned long flags;
+	struct bucket *b;
+	u32 key_size, hash;
+	int ret;
+
+	if (unlikely(map_flags > BPF_EXIST))
+		/* unknown flags */
+		return -EINVAL;
+
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+		     !rcu_read_lock_bh_held());
+
+	key_size = map->key_size;
+
+	hash = htab_map_hash(key, key_size, htab->hashrnd);
+
+	b = __select_bucket(htab, hash);
+	head = &b->head;
+
+	ret = htab_lock_bucket(htab, b, hash, &flags);
+	if (ret)
+		return ret;
+
+	l_old = lookup_elem_raw(head, hash, key, key_size);
+
+	ret = check_flags(htab, l_old, map_flags);
+	if (ret)
+		goto err;
+
+	if (l_old) {
+		/* per-cpu hash map can update value in-place */
+		pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
+				value, onallcpus);
+	} else {
+		l_new = alloc_htab_elem(htab, key, value, key_size,
+					hash, true, onallcpus, NULL);
+		if (IS_ERR(l_new)) {
+			ret = PTR_ERR(l_new);
+			goto err;
+		}
+		hlist_nulls_add_head_rcu(&l_new->hash_node, head);
+	}
+	ret = 0;
+err:
+	htab_unlock_bucket(htab, b, hash, flags);
+	return ret;
+}
+
+static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
+					     void *value, u64 map_flags,
+					     bool onallcpus)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct htab_elem *l_new = NULL, *l_old;
+	struct hlist_nulls_head *head;
+	unsigned long flags;
+	struct bucket *b;
+	u32 key_size, hash;
+	int ret;
+
+	if (unlikely(map_flags > BPF_EXIST))
+		/* unknown flags */
+		return -EINVAL;
+
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+		     !rcu_read_lock_bh_held());
+
+	key_size = map->key_size;
+
+	hash = htab_map_hash(key, key_size, htab->hashrnd);
+
+	b = __select_bucket(htab, hash);
+	head = &b->head;
+
+	/* For LRU, we need to alloc before taking bucket's
+	 * spinlock because LRU's elem alloc may need
+	 * to remove older elem from htab and this removal
+	 * operation will need a bucket lock.
+	 */
+	if (map_flags != BPF_EXIST) {
+		l_new = prealloc_lru_pop(htab, key, hash);
+		if (!l_new)
+			return -ENOMEM;
+	}
+
+	ret = htab_lock_bucket(htab, b, hash, &flags);
+	if (ret)
+		goto err_lock_bucket;
+
+	l_old = lookup_elem_raw(head, hash, key, key_size);
+
+	ret = check_flags(htab, l_old, map_flags);
+	if (ret)
+		goto err;
+
+	if (l_old) {
+		bpf_lru_node_set_ref(&l_old->lru_node);
+
+		/* per-cpu hash map can update value in-place */
+		pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
+				value, onallcpus);
+	} else {
+		pcpu_init_value(htab, htab_elem_get_ptr(l_new, key_size),
+				value, onallcpus);
+		hlist_nulls_add_head_rcu(&l_new->hash_node, head);
+		l_new = NULL;
+	}
+	ret = 0;
+err:
+	htab_unlock_bucket(htab, b, hash, flags);
+err_lock_bucket:
+	if (l_new)
+		bpf_lru_push_free(&htab->lru, &l_new->lru_node);
+	return ret;
+}
+
+static int htab_percpu_map_update_elem(struct bpf_map *map, void *key,
+				       void *value, u64 map_flags)
+{
+	return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
+}
+
+static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
+					   void *value, u64 map_flags)
+{
+	return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
+						 false);
+}
+
+/* Called from syscall or from eBPF program */
+static int htab_map_delete_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct hlist_nulls_head *head;
+	struct bucket *b;
+	struct htab_elem *l;
+	unsigned long flags;
+	u32 hash, key_size;
+	int ret;
+
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+		     !rcu_read_lock_bh_held());
+
+	key_size = map->key_size;
+
+	hash = htab_map_hash(key, key_size, htab->hashrnd);
+	b = __select_bucket(htab, hash);
+	head = &b->head;
+
+	ret = htab_lock_bucket(htab, b, hash, &flags);
+	if (ret)
+		return ret;
+
+	l = lookup_elem_raw(head, hash, key, key_size);
+
+	if (l) {
+		hlist_nulls_del_rcu(&l->hash_node);
+		free_htab_elem(htab, l);
+	} else {
+		ret = -ENOENT;
+	}
+
+	htab_unlock_bucket(htab, b, hash, flags);
+	return ret;
+}
+
+static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct hlist_nulls_head *head;
+	struct bucket *b;
+	struct htab_elem *l;
+	unsigned long flags;
+	u32 hash, key_size;
+	int ret;
+
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+		     !rcu_read_lock_bh_held());
+
+	key_size = map->key_size;
+
+	hash = htab_map_hash(key, key_size, htab->hashrnd);
+	b = __select_bucket(htab, hash);
+	head = &b->head;
+
+	ret = htab_lock_bucket(htab, b, hash, &flags);
+	if (ret)
+		return ret;
+
+	l = lookup_elem_raw(head, hash, key, key_size);
+
+	if (l)
+		hlist_nulls_del_rcu(&l->hash_node);
+	else
+		ret = -ENOENT;
+
+	htab_unlock_bucket(htab, b, hash, flags);
+	if (l)
+		htab_lru_push_free(htab, l);
+	return ret;
+}
+
+static void delete_all_elements(struct bpf_htab *htab)
+{
+	int i;
+
+	/* It's called from a worker thread, so disable migration here,
+	 * since bpf_mem_cache_free() relies on that.
+	 */
+	migrate_disable();
+	for (i = 0; i < htab->n_buckets; i++) {
+		struct hlist_nulls_head *head = select_bucket(htab, i);
+		struct hlist_nulls_node *n;
+		struct htab_elem *l;
+
+		hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
+			hlist_nulls_del_rcu(&l->hash_node);
+			htab_elem_free(htab, l);
+		}
+	}
+	migrate_enable();
+}
+
+static void htab_free_malloced_timers(struct bpf_htab *htab)
+{
+	int i;
+
+	rcu_read_lock();
+	for (i = 0; i < htab->n_buckets; i++) {
+		struct hlist_nulls_head *head = select_bucket(htab, i);
+		struct hlist_nulls_node *n;
+		struct htab_elem *l;
+
+		hlist_nulls_for_each_entry(l, n, head, hash_node) {
+			/* We don't reset or free kptr on uref dropping to zero,
+			 * hence just free timer.
+			 */
+			bpf_timer_cancel_and_free(l->key +
+						  round_up(htab->map.key_size, 8) +
+						  htab->map.timer_off);
+		}
+		cond_resched_rcu();
+	}
+	rcu_read_unlock();
+}
+
+static void htab_map_free_timers(struct bpf_map *map)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+
+	/* We don't reset or free kptr on uref dropping to zero. */
+	if (!map_value_has_timer(&htab->map))
+		return;
+	if (!htab_is_prealloc(htab))
+		htab_free_malloced_timers(htab);
+	else
+		htab_free_prealloced_timers(htab);
+}
+
+/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
+static void htab_map_free(struct bpf_map *map)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	int i;
+
+	/* bpf_free_used_maps() or close(map_fd) will trigger this map_free callback.
+	 * bpf_free_used_maps() is called after bpf prog is no longer executing.
+	 * There is no need to synchronize_rcu() here to protect map elements.
+	 */
+
+	/* htab no longer uses call_rcu() directly. bpf_mem_alloc does it
+	 * underneath and is reponsible for waiting for callbacks to finish
+	 * during bpf_mem_alloc_destroy().
+	 */
+	if (!htab_is_prealloc(htab)) {
+		delete_all_elements(htab);
+	} else {
+		htab_free_prealloced_kptrs(htab);
+		prealloc_destroy(htab);
+	}
+
+	bpf_map_free_kptr_off_tab(map);
+	free_percpu(htab->extra_elems);
+	bpf_map_area_free(htab->buckets);
+	bpf_mem_alloc_destroy(&htab->pcpu_ma);
+	bpf_mem_alloc_destroy(&htab->ma);
+	if (htab->use_percpu_counter)
+		percpu_counter_destroy(&htab->pcount);
+	for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
+		free_percpu(htab->map_locked[i]);
+	lockdep_unregister_key(&htab->lockdep_key);
+	bpf_map_area_free(htab);
+}
+
+static void htab_map_seq_show_elem(struct bpf_map *map, void *key,
+				   struct seq_file *m)
+{
+	void *value;
+
+	rcu_read_lock();
+
+	value = htab_map_lookup_elem(map, key);
+	if (!value) {
+		rcu_read_unlock();
+		return;
+	}
+
+	btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
+	seq_puts(m, ": ");
+	btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
+	seq_puts(m, "\n");
+
+	rcu_read_unlock();
+}
+
+static int __htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
+					     void *value, bool is_lru_map,
+					     bool is_percpu, u64 flags)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct hlist_nulls_head *head;
+	unsigned long bflags;
+	struct htab_elem *l;
+	u32 hash, key_size;
+	struct bucket *b;
+	int ret;
+
+	key_size = map->key_size;
+
+	hash = htab_map_hash(key, key_size, htab->hashrnd);
+	b = __select_bucket(htab, hash);
+	head = &b->head;
+
+	ret = htab_lock_bucket(htab, b, hash, &bflags);
+	if (ret)
+		return ret;
+
+	l = lookup_elem_raw(head, hash, key, key_size);
+	if (!l) {
+		ret = -ENOENT;
+	} else {
+		if (is_percpu) {
+			u32 roundup_value_size = round_up(map->value_size, 8);
+			void __percpu *pptr;
+			int off = 0, cpu;
+
+			pptr = htab_elem_get_ptr(l, key_size);
+			for_each_possible_cpu(cpu) {
+				bpf_long_memcpy(value + off,
+						per_cpu_ptr(pptr, cpu),
+						roundup_value_size);
+				off += roundup_value_size;
+			}
+		} else {
+			u32 roundup_key_size = round_up(map->key_size, 8);
+
+			if (flags & BPF_F_LOCK)
+				copy_map_value_locked(map, value, l->key +
+						      roundup_key_size,
+						      true);
+			else
+				copy_map_value(map, value, l->key +
+					       roundup_key_size);
+			/* Zeroing special fields in the temp buffer */
+			check_and_init_map_value(map, value);
+		}
+
+		hlist_nulls_del_rcu(&l->hash_node);
+		if (!is_lru_map)
+			free_htab_elem(htab, l);
+	}
+
+	htab_unlock_bucket(htab, b, hash, bflags);
+
+	if (is_lru_map && l)
+		htab_lru_push_free(htab, l);
+
+	return ret;
+}
+
+static int htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
+					   void *value, u64 flags)
+{
+	return __htab_map_lookup_and_delete_elem(map, key, value, false, false,
+						 flags);
+}
+
+static int htab_percpu_map_lookup_and_delete_elem(struct bpf_map *map,
+						  void *key, void *value,
+						  u64 flags)
+{
+	return __htab_map_lookup_and_delete_elem(map, key, value, false, true,
+						 flags);
+}
+
+static int htab_lru_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
+					       void *value, u64 flags)
+{
+	return __htab_map_lookup_and_delete_elem(map, key, value, true, false,
+						 flags);
+}
+
+static int htab_lru_percpu_map_lookup_and_delete_elem(struct bpf_map *map,
+						      void *key, void *value,
+						      u64 flags)
+{
+	return __htab_map_lookup_and_delete_elem(map, key, value, true, true,
+						 flags);
+}
+
+static int
+__htab_map_lookup_and_delete_batch(struct bpf_map *map,
+				   const union bpf_attr *attr,
+				   union bpf_attr __user *uattr,
+				   bool do_delete, bool is_lru_map,
+				   bool is_percpu)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	u32 bucket_cnt, total, key_size, value_size, roundup_key_size;
+	void *keys = NULL, *values = NULL, *value, *dst_key, *dst_val;
+	void __user *uvalues = u64_to_user_ptr(attr->batch.values);
+	void __user *ukeys = u64_to_user_ptr(attr->batch.keys);
+	void __user *ubatch = u64_to_user_ptr(attr->batch.in_batch);
+	u32 batch, max_count, size, bucket_size, map_id;
+	struct htab_elem *node_to_free = NULL;
+	u64 elem_map_flags, map_flags;
+	struct hlist_nulls_head *head;
+	struct hlist_nulls_node *n;
+	unsigned long flags = 0;
+	bool locked = false;
+	struct htab_elem *l;
+	struct bucket *b;
+	int ret = 0;
+
+	elem_map_flags = attr->batch.elem_flags;
+	if ((elem_map_flags & ~BPF_F_LOCK) ||
+	    ((elem_map_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map)))
+		return -EINVAL;
+
+	map_flags = attr->batch.flags;
+	if (map_flags)
+		return -EINVAL;
+
+	max_count = attr->batch.count;
+	if (!max_count)
+		return 0;
+
+	if (put_user(0, &uattr->batch.count))
+		return -EFAULT;
+
+	batch = 0;
+	if (ubatch && copy_from_user(&batch, ubatch, sizeof(batch)))
+		return -EFAULT;
+
+	if (batch >= htab->n_buckets)
+		return -ENOENT;
+
+	key_size = htab->map.key_size;
+	roundup_key_size = round_up(htab->map.key_size, 8);
+	value_size = htab->map.value_size;
+	size = round_up(value_size, 8);
+	if (is_percpu)
+		value_size = size * num_possible_cpus();
+	total = 0;
+	/* while experimenting with hash tables with sizes ranging from 10 to
+	 * 1000, it was observed that a bucket can have up to 5 entries.
+	 */
+	bucket_size = 5;
+
+alloc:
+	/* We cannot do copy_from_user or copy_to_user inside
+	 * the rcu_read_lock. Allocate enough space here.
+	 */
+	keys = kvmalloc_array(key_size, bucket_size, GFP_USER | __GFP_NOWARN);
+	values = kvmalloc_array(value_size, bucket_size, GFP_USER | __GFP_NOWARN);
+	if (!keys || !values) {
+		ret = -ENOMEM;
+		goto after_loop;
+	}
+
+again:
+	bpf_disable_instrumentation();
+	rcu_read_lock();
+again_nocopy:
+	dst_key = keys;
+	dst_val = values;
+	b = &htab->buckets[batch];
+	head = &b->head;
+	/* do not grab the lock unless need it (bucket_cnt > 0). */
+	if (locked) {
+		ret = htab_lock_bucket(htab, b, batch, &flags);
+		if (ret) {
+			rcu_read_unlock();
+			bpf_enable_instrumentation();
+			goto after_loop;
+		}
+	}
+
+	bucket_cnt = 0;
+	hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
+		bucket_cnt++;
+
+	if (bucket_cnt && !locked) {
+		locked = true;
+		goto again_nocopy;
+	}
+
+	if (bucket_cnt > (max_count - total)) {
+		if (total == 0)
+			ret = -ENOSPC;
+		/* Note that since bucket_cnt > 0 here, it is implicit
+		 * that the locked was grabbed, so release it.
+		 */
+		htab_unlock_bucket(htab, b, batch, flags);
+		rcu_read_unlock();
+		bpf_enable_instrumentation();
+		goto after_loop;
+	}
+
+	if (bucket_cnt > bucket_size) {
+		bucket_size = bucket_cnt;
+		/* Note that since bucket_cnt > 0 here, it is implicit
+		 * that the locked was grabbed, so release it.
+		 */
+		htab_unlock_bucket(htab, b, batch, flags);
+		rcu_read_unlock();
+		bpf_enable_instrumentation();
+		kvfree(keys);
+		kvfree(values);
+		goto alloc;
+	}
+
+	/* Next block is only safe to run if you have grabbed the lock */
+	if (!locked)
+		goto next_batch;
+
+	hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
+		memcpy(dst_key, l->key, key_size);
+
+		if (is_percpu) {
+			int off = 0, cpu;
+			void __percpu *pptr;
+
+			pptr = htab_elem_get_ptr(l, map->key_size);
+			for_each_possible_cpu(cpu) {
+				bpf_long_memcpy(dst_val + off,
+						per_cpu_ptr(pptr, cpu), size);
+				off += size;
+			}
+		} else {
+			value = l->key + roundup_key_size;
+			if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
+				struct bpf_map **inner_map = value;
+
+				 /* Actual value is the id of the inner map */
+				map_id = map->ops->map_fd_sys_lookup_elem(*inner_map);
+				value = &map_id;
+			}
+
+			if (elem_map_flags & BPF_F_LOCK)
+				copy_map_value_locked(map, dst_val, value,
+						      true);
+			else
+				copy_map_value(map, dst_val, value);
+			/* Zeroing special fields in the temp buffer */
+			check_and_init_map_value(map, dst_val);
+		}
+		if (do_delete) {
+			hlist_nulls_del_rcu(&l->hash_node);
+
+			/* bpf_lru_push_free() will acquire lru_lock, which
+			 * may cause deadlock. See comments in function
+			 * prealloc_lru_pop(). Let us do bpf_lru_push_free()
+			 * after releasing the bucket lock.
+			 */
+			if (is_lru_map) {
+				l->batch_flink = node_to_free;
+				node_to_free = l;
+			} else {
+				free_htab_elem(htab, l);
+			}
+		}
+		dst_key += key_size;
+		dst_val += value_size;
+	}
+
+	htab_unlock_bucket(htab, b, batch, flags);
+	locked = false;
+
+	while (node_to_free) {
+		l = node_to_free;
+		node_to_free = node_to_free->batch_flink;
+		htab_lru_push_free(htab, l);
+	}
+
+next_batch:
+	/* If we are not copying data, we can go to next bucket and avoid
+	 * unlocking the rcu.
+	 */
+	if (!bucket_cnt && (batch + 1 < htab->n_buckets)) {
+		batch++;
+		goto again_nocopy;
+	}
+
+	rcu_read_unlock();
+	bpf_enable_instrumentation();
+	if (bucket_cnt && (copy_to_user(ukeys + total * key_size, keys,
+	    key_size * bucket_cnt) ||
+	    copy_to_user(uvalues + total * value_size, values,
+	    value_size * bucket_cnt))) {
+		ret = -EFAULT;
+		goto after_loop;
+	}
+
+	total += bucket_cnt;
+	batch++;
+	if (batch >= htab->n_buckets) {
+		ret = -ENOENT;
+		goto after_loop;
+	}
+	goto again;
+
+after_loop:
+	if (ret == -EFAULT)
+		goto out;
+
+	/* copy # of entries and next batch */
+	ubatch = u64_to_user_ptr(attr->batch.out_batch);
+	if (copy_to_user(ubatch, &batch, sizeof(batch)) ||
+	    put_user(total, &uattr->batch.count))
+		ret = -EFAULT;
+
+out:
+	kvfree(keys);
+	kvfree(values);
+	return ret;
+}
+
+static int
+htab_percpu_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
+			     union bpf_attr __user *uattr)
+{
+	return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
+						  false, true);
+}
+
+static int
+htab_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
+					const union bpf_attr *attr,
+					union bpf_attr __user *uattr)
+{
+	return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
+						  false, true);
+}
+
+static int
+htab_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
+		      union bpf_attr __user *uattr)
+{
+	return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
+						  false, false);
+}
+
+static int
+htab_map_lookup_and_delete_batch(struct bpf_map *map,
+				 const union bpf_attr *attr,
+				 union bpf_attr __user *uattr)
+{
+	return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
+						  false, false);
+}
+
+static int
+htab_lru_percpu_map_lookup_batch(struct bpf_map *map,
+				 const union bpf_attr *attr,
+				 union bpf_attr __user *uattr)
+{
+	return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
+						  true, true);
+}
+
+static int
+htab_lru_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
+					    const union bpf_attr *attr,
+					    union bpf_attr __user *uattr)
+{
+	return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
+						  true, true);
+}
+
+static int
+htab_lru_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
+			  union bpf_attr __user *uattr)
+{
+	return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
+						  true, false);
+}
+
+static int
+htab_lru_map_lookup_and_delete_batch(struct bpf_map *map,
+				     const union bpf_attr *attr,
+				     union bpf_attr __user *uattr)
+{
+	return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
+						  true, false);
+}
+
+struct bpf_iter_seq_hash_map_info {
+	struct bpf_map *map;
+	struct bpf_htab *htab;
+	void *percpu_value_buf; // non-zero means percpu hash
+	u32 bucket_id;
+	u32 skip_elems;
+};
+
+static struct htab_elem *
+bpf_hash_map_seq_find_next(struct bpf_iter_seq_hash_map_info *info,
+			   struct htab_elem *prev_elem)
+{
+	const struct bpf_htab *htab = info->htab;
+	u32 skip_elems = info->skip_elems;
+	u32 bucket_id = info->bucket_id;
+	struct hlist_nulls_head *head;
+	struct hlist_nulls_node *n;
+	struct htab_elem *elem;
+	struct bucket *b;
+	u32 i, count;
+
+	if (bucket_id >= htab->n_buckets)
+		return NULL;
+
+	/* try to find next elem in the same bucket */
+	if (prev_elem) {
+		/* no update/deletion on this bucket, prev_elem should be still valid
+		 * and we won't skip elements.
+		 */
+		n = rcu_dereference_raw(hlist_nulls_next_rcu(&prev_elem->hash_node));
+		elem = hlist_nulls_entry_safe(n, struct htab_elem, hash_node);
+		if (elem)
+			return elem;
+
+		/* not found, unlock and go to the next bucket */
+		b = &htab->buckets[bucket_id++];
+		rcu_read_unlock();
+		skip_elems = 0;
+	}
+
+	for (i = bucket_id; i < htab->n_buckets; i++) {
+		b = &htab->buckets[i];
+		rcu_read_lock();
+
+		count = 0;
+		head = &b->head;
+		hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
+			if (count >= skip_elems) {
+				info->bucket_id = i;
+				info->skip_elems = count;
+				return elem;
+			}
+			count++;
+		}
+
+		rcu_read_unlock();
+		skip_elems = 0;
+	}
+
+	info->bucket_id = i;
+	info->skip_elems = 0;
+	return NULL;
+}
+
+static void *bpf_hash_map_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct bpf_iter_seq_hash_map_info *info = seq->private;
+	struct htab_elem *elem;
+
+	elem = bpf_hash_map_seq_find_next(info, NULL);
+	if (!elem)
+		return NULL;
+
+	if (*pos == 0)
+		++*pos;
+	return elem;
+}
+
+static void *bpf_hash_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct bpf_iter_seq_hash_map_info *info = seq->private;
+
+	++*pos;
+	++info->skip_elems;
+	return bpf_hash_map_seq_find_next(info, v);
+}
+
+static int __bpf_hash_map_seq_show(struct seq_file *seq, struct htab_elem *elem)
+{
+	struct bpf_iter_seq_hash_map_info *info = seq->private;
+	u32 roundup_key_size, roundup_value_size;
+	struct bpf_iter__bpf_map_elem ctx = {};
+	struct bpf_map *map = info->map;
+	struct bpf_iter_meta meta;
+	int ret = 0, off = 0, cpu;
+	struct bpf_prog *prog;
+	void __percpu *pptr;
+
+	meta.seq = seq;
+	prog = bpf_iter_get_info(&meta, elem == NULL);
+	if (prog) {
+		ctx.meta = &meta;
+		ctx.map = info->map;
+		if (elem) {
+			roundup_key_size = round_up(map->key_size, 8);
+			ctx.key = elem->key;
+			if (!info->percpu_value_buf) {
+				ctx.value = elem->key + roundup_key_size;
+			} else {
+				roundup_value_size = round_up(map->value_size, 8);
+				pptr = htab_elem_get_ptr(elem, map->key_size);
+				for_each_possible_cpu(cpu) {
+					bpf_long_memcpy(info->percpu_value_buf + off,
+							per_cpu_ptr(pptr, cpu),
+							roundup_value_size);
+					off += roundup_value_size;
+				}
+				ctx.value = info->percpu_value_buf;
+			}
+		}
+		ret = bpf_iter_run_prog(prog, &ctx);
+	}
+
+	return ret;
+}
+
+static int bpf_hash_map_seq_show(struct seq_file *seq, void *v)
+{
+	return __bpf_hash_map_seq_show(seq, v);
+}
+
+static void bpf_hash_map_seq_stop(struct seq_file *seq, void *v)
+{
+	if (!v)
+		(void)__bpf_hash_map_seq_show(seq, NULL);
+	else
+		rcu_read_unlock();
+}
+
+static int bpf_iter_init_hash_map(void *priv_data,
+				  struct bpf_iter_aux_info *aux)
+{
+	struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
+	struct bpf_map *map = aux->map;
+	void *value_buf;
+	u32 buf_size;
+
+	if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+	    map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
+		buf_size = round_up(map->value_size, 8) * num_possible_cpus();
+		value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
+		if (!value_buf)
+			return -ENOMEM;
+
+		seq_info->percpu_value_buf = value_buf;
+	}
+
+	bpf_map_inc_with_uref(map);
+	seq_info->map = map;
+	seq_info->htab = container_of(map, struct bpf_htab, map);
+	return 0;
+}
+
+static void bpf_iter_fini_hash_map(void *priv_data)
+{
+	struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
+
+	bpf_map_put_with_uref(seq_info->map);
+	kfree(seq_info->percpu_value_buf);
+}
+
+static const struct seq_operations bpf_hash_map_seq_ops = {
+	.start	= bpf_hash_map_seq_start,
+	.next	= bpf_hash_map_seq_next,
+	.stop	= bpf_hash_map_seq_stop,
+	.show	= bpf_hash_map_seq_show,
+};
+
+static const struct bpf_iter_seq_info iter_seq_info = {
+	.seq_ops		= &bpf_hash_map_seq_ops,
+	.init_seq_private	= bpf_iter_init_hash_map,
+	.fini_seq_private	= bpf_iter_fini_hash_map,
+	.seq_priv_size		= sizeof(struct bpf_iter_seq_hash_map_info),
+};
+
+static int bpf_for_each_hash_elem(struct bpf_map *map, bpf_callback_t callback_fn,
+				  void *callback_ctx, u64 flags)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct hlist_nulls_head *head;
+	struct hlist_nulls_node *n;
+	struct htab_elem *elem;
+	u32 roundup_key_size;
+	int i, num_elems = 0;
+	void __percpu *pptr;
+	struct bucket *b;
+	void *key, *val;
+	bool is_percpu;
+	u64 ret = 0;
+
+	if (flags != 0)
+		return -EINVAL;
+
+	is_percpu = htab_is_percpu(htab);
+
+	roundup_key_size = round_up(map->key_size, 8);
+	/* disable migration so percpu value prepared here will be the
+	 * same as the one seen by the bpf program with bpf_map_lookup_elem().
+	 */
+	if (is_percpu)
+		migrate_disable();
+	for (i = 0; i < htab->n_buckets; i++) {
+		b = &htab->buckets[i];
+		rcu_read_lock();
+		head = &b->head;
+		hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
+			key = elem->key;
+			if (is_percpu) {
+				/* current cpu value for percpu map */
+				pptr = htab_elem_get_ptr(elem, map->key_size);
+				val = this_cpu_ptr(pptr);
+			} else {
+				val = elem->key + roundup_key_size;
+			}
+			num_elems++;
+			ret = callback_fn((u64)(long)map, (u64)(long)key,
+					  (u64)(long)val, (u64)(long)callback_ctx, 0);
+			/* return value: 0 - continue, 1 - stop and return */
+			if (ret) {
+				rcu_read_unlock();
+				goto out;
+			}
+		}
+		rcu_read_unlock();
+	}
+out:
+	if (is_percpu)
+		migrate_enable();
+	return num_elems;
+}
+
+BTF_ID_LIST_SINGLE(htab_map_btf_ids, struct, bpf_htab)
+const struct bpf_map_ops htab_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = htab_map_alloc_check,
+	.map_alloc = htab_map_alloc,
+	.map_free = htab_map_free,
+	.map_get_next_key = htab_map_get_next_key,
+	.map_release_uref = htab_map_free_timers,
+	.map_lookup_elem = htab_map_lookup_elem,
+	.map_lookup_and_delete_elem = htab_map_lookup_and_delete_elem,
+	.map_update_elem = htab_map_update_elem,
+	.map_delete_elem = htab_map_delete_elem,
+	.map_gen_lookup = htab_map_gen_lookup,
+	.map_seq_show_elem = htab_map_seq_show_elem,
+	.map_set_for_each_callback_args = map_set_for_each_callback_args,
+	.map_for_each_callback = bpf_for_each_hash_elem,
+	BATCH_OPS(htab),
+	.map_btf_id = &htab_map_btf_ids[0],
+	.iter_seq_info = &iter_seq_info,
+};
+
+const struct bpf_map_ops htab_lru_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = htab_map_alloc_check,
+	.map_alloc = htab_map_alloc,
+	.map_free = htab_map_free,
+	.map_get_next_key = htab_map_get_next_key,
+	.map_release_uref = htab_map_free_timers,
+	.map_lookup_elem = htab_lru_map_lookup_elem,
+	.map_lookup_and_delete_elem = htab_lru_map_lookup_and_delete_elem,
+	.map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys,
+	.map_update_elem = htab_lru_map_update_elem,
+	.map_delete_elem = htab_lru_map_delete_elem,
+	.map_gen_lookup = htab_lru_map_gen_lookup,
+	.map_seq_show_elem = htab_map_seq_show_elem,
+	.map_set_for_each_callback_args = map_set_for_each_callback_args,
+	.map_for_each_callback = bpf_for_each_hash_elem,
+	BATCH_OPS(htab_lru),
+	.map_btf_id = &htab_map_btf_ids[0],
+	.iter_seq_info = &iter_seq_info,
+};
+
+/* Called from eBPF program */
+static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct htab_elem *l = __htab_map_lookup_elem(map, key);
+
+	if (l)
+		return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
+	else
+		return NULL;
+}
+
+static void *htab_percpu_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
+{
+	struct htab_elem *l;
+
+	if (cpu >= nr_cpu_ids)
+		return NULL;
+
+	l = __htab_map_lookup_elem(map, key);
+	if (l)
+		return per_cpu_ptr(htab_elem_get_ptr(l, map->key_size), cpu);
+	else
+		return NULL;
+}
+
+static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct htab_elem *l = __htab_map_lookup_elem(map, key);
+
+	if (l) {
+		bpf_lru_node_set_ref(&l->lru_node);
+		return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
+	}
+
+	return NULL;
+}
+
+static void *htab_lru_percpu_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
+{
+	struct htab_elem *l;
+
+	if (cpu >= nr_cpu_ids)
+		return NULL;
+
+	l = __htab_map_lookup_elem(map, key);
+	if (l) {
+		bpf_lru_node_set_ref(&l->lru_node);
+		return per_cpu_ptr(htab_elem_get_ptr(l, map->key_size), cpu);
+	}
+
+	return NULL;
+}
+
+int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
+{
+	struct htab_elem *l;
+	void __percpu *pptr;
+	int ret = -ENOENT;
+	int cpu, off = 0;
+	u32 size;
+
+	/* per_cpu areas are zero-filled and bpf programs can only
+	 * access 'value_size' of them, so copying rounded areas
+	 * will not leak any kernel data
+	 */
+	size = round_up(map->value_size, 8);
+	rcu_read_lock();
+	l = __htab_map_lookup_elem(map, key);
+	if (!l)
+		goto out;
+	/* We do not mark LRU map element here in order to not mess up
+	 * eviction heuristics when user space does a map walk.
+	 */
+	pptr = htab_elem_get_ptr(l, map->key_size);
+	for_each_possible_cpu(cpu) {
+		bpf_long_memcpy(value + off,
+				per_cpu_ptr(pptr, cpu), size);
+		off += size;
+	}
+	ret = 0;
+out:
+	rcu_read_unlock();
+	return ret;
+}
+
+int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
+			   u64 map_flags)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	int ret;
+
+	rcu_read_lock();
+	if (htab_is_lru(htab))
+		ret = __htab_lru_percpu_map_update_elem(map, key, value,
+							map_flags, true);
+	else
+		ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
+						    true);
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static void htab_percpu_map_seq_show_elem(struct bpf_map *map, void *key,
+					  struct seq_file *m)
+{
+	struct htab_elem *l;
+	void __percpu *pptr;
+	int cpu;
+
+	rcu_read_lock();
+
+	l = __htab_map_lookup_elem(map, key);
+	if (!l) {
+		rcu_read_unlock();
+		return;
+	}
+
+	btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
+	seq_puts(m, ": {\n");
+	pptr = htab_elem_get_ptr(l, map->key_size);
+	for_each_possible_cpu(cpu) {
+		seq_printf(m, "\tcpu%d: ", cpu);
+		btf_type_seq_show(map->btf, map->btf_value_type_id,
+				  per_cpu_ptr(pptr, cpu), m);
+		seq_puts(m, "\n");
+	}
+	seq_puts(m, "}\n");
+
+	rcu_read_unlock();
+}
+
+const struct bpf_map_ops htab_percpu_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = htab_map_alloc_check,
+	.map_alloc = htab_map_alloc,
+	.map_free = htab_map_free,
+	.map_get_next_key = htab_map_get_next_key,
+	.map_lookup_elem = htab_percpu_map_lookup_elem,
+	.map_lookup_and_delete_elem = htab_percpu_map_lookup_and_delete_elem,
+	.map_update_elem = htab_percpu_map_update_elem,
+	.map_delete_elem = htab_map_delete_elem,
+	.map_lookup_percpu_elem = htab_percpu_map_lookup_percpu_elem,
+	.map_seq_show_elem = htab_percpu_map_seq_show_elem,
+	.map_set_for_each_callback_args = map_set_for_each_callback_args,
+	.map_for_each_callback = bpf_for_each_hash_elem,
+	BATCH_OPS(htab_percpu),
+	.map_btf_id = &htab_map_btf_ids[0],
+	.iter_seq_info = &iter_seq_info,
+};
+
+const struct bpf_map_ops htab_lru_percpu_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = htab_map_alloc_check,
+	.map_alloc = htab_map_alloc,
+	.map_free = htab_map_free,
+	.map_get_next_key = htab_map_get_next_key,
+	.map_lookup_elem = htab_lru_percpu_map_lookup_elem,
+	.map_lookup_and_delete_elem = htab_lru_percpu_map_lookup_and_delete_elem,
+	.map_update_elem = htab_lru_percpu_map_update_elem,
+	.map_delete_elem = htab_lru_map_delete_elem,
+	.map_lookup_percpu_elem = htab_lru_percpu_map_lookup_percpu_elem,
+	.map_seq_show_elem = htab_percpu_map_seq_show_elem,
+	.map_set_for_each_callback_args = map_set_for_each_callback_args,
+	.map_for_each_callback = bpf_for_each_hash_elem,
+	BATCH_OPS(htab_lru_percpu),
+	.map_btf_id = &htab_map_btf_ids[0],
+	.iter_seq_info = &iter_seq_info,
+};
+
+static int fd_htab_map_alloc_check(union bpf_attr *attr)
+{
+	if (attr->value_size != sizeof(u32))
+		return -EINVAL;
+	return htab_map_alloc_check(attr);
+}
+
+static void fd_htab_map_free(struct bpf_map *map)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct hlist_nulls_node *n;
+	struct hlist_nulls_head *head;
+	struct htab_elem *l;
+	int i;
+
+	for (i = 0; i < htab->n_buckets; i++) {
+		head = select_bucket(htab, i);
+
+		hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
+			void *ptr = fd_htab_map_get_ptr(map, l);
+
+			map->ops->map_fd_put_ptr(map, ptr, false);
+		}
+	}
+
+	htab_map_free(map);
+}
+
+/* only called from syscall */
+int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
+{
+	void **ptr;
+	int ret = 0;
+
+	if (!map->ops->map_fd_sys_lookup_elem)
+		return -ENOTSUPP;
+
+	rcu_read_lock();
+	ptr = htab_map_lookup_elem(map, key);
+	if (ptr)
+		*value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
+	else
+		ret = -ENOENT;
+	rcu_read_unlock();
+
+	return ret;
+}
+
+/* only called from syscall */
+int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
+				void *key, void *value, u64 map_flags)
+{
+	void *ptr;
+	int ret;
+	u32 ufd = *(u32 *)value;
+
+	ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+
+	ret = htab_map_update_elem(map, key, &ptr, map_flags);
+	if (ret)
+		map->ops->map_fd_put_ptr(map, ptr, false);
+
+	return ret;
+}
+
+static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_map *map, *inner_map_meta;
+
+	inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
+	if (IS_ERR(inner_map_meta))
+		return inner_map_meta;
+
+	map = htab_map_alloc(attr);
+	if (IS_ERR(map)) {
+		bpf_map_meta_free(inner_map_meta);
+		return map;
+	}
+
+	map->inner_map_meta = inner_map_meta;
+
+	return map;
+}
+
+static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_map **inner_map  = htab_map_lookup_elem(map, key);
+
+	if (!inner_map)
+		return NULL;
+
+	return READ_ONCE(*inner_map);
+}
+
+static int htab_of_map_gen_lookup(struct bpf_map *map,
+				  struct bpf_insn *insn_buf)
+{
+	struct bpf_insn *insn = insn_buf;
+	const int ret = BPF_REG_0;
+
+	BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
+		     (void *(*)(struct bpf_map *map, void *key))NULL));
+	*insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
+	*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2);
+	*insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
+				offsetof(struct htab_elem, key) +
+				round_up(map->key_size, 8));
+	*insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
+
+	return insn - insn_buf;
+}
+
+static void htab_of_map_free(struct bpf_map *map)
+{
+	bpf_map_meta_free(map->inner_map_meta);
+	fd_htab_map_free(map);
+}
+
+const struct bpf_map_ops htab_of_maps_map_ops = {
+	.map_alloc_check = fd_htab_map_alloc_check,
+	.map_alloc = htab_of_map_alloc,
+	.map_free = htab_of_map_free,
+	.map_get_next_key = htab_map_get_next_key,
+	.map_lookup_elem = htab_of_map_lookup_elem,
+	.map_delete_elem = htab_map_delete_elem,
+	.map_fd_get_ptr = bpf_map_fd_get_ptr,
+	.map_fd_put_ptr = bpf_map_fd_put_ptr,
+	.map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
+	.map_gen_lookup = htab_of_map_gen_lookup,
+	.map_check_btf = map_check_no_btf,
+	BATCH_OPS(htab),
+	.map_btf_id = &htab_map_btf_ids[0],
+};
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
new file mode 100644
index 000000000..6212e4ae0
--- /dev/null
+++ b/kernel/bpf/helpers.c
@@ -0,0 +1,1726 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ */
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/bpf-cgroup.h>
+#include <linux/rcupdate.h>
+#include <linux/random.h>
+#include <linux/smp.h>
+#include <linux/topology.h>
+#include <linux/ktime.h>
+#include <linux/sched.h>
+#include <linux/uidgid.h>
+#include <linux/filter.h>
+#include <linux/ctype.h>
+#include <linux/jiffies.h>
+#include <linux/pid_namespace.h>
+#include <linux/poison.h>
+#include <linux/proc_ns.h>
+#include <linux/security.h>
+#include <linux/btf_ids.h>
+
+#include "../../lib/kstrtox.h"
+
+/* If kernel subsystem is allowing eBPF programs to call this function,
+ * inside its own verifier_ops->get_func_proto() callback it should return
+ * bpf_map_lookup_elem_proto, so that verifier can properly check the arguments
+ *
+ * Different map implementations will rely on rcu in map methods
+ * lookup/update/delete, therefore eBPF programs must run under rcu lock
+ * if program is allowed to access maps, so check rcu_read_lock_held in
+ * all three functions.
+ */
+BPF_CALL_2(bpf_map_lookup_elem, struct bpf_map *, map, void *, key)
+{
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
+	return (unsigned long) map->ops->map_lookup_elem(map, key);
+}
+
+const struct bpf_func_proto bpf_map_lookup_elem_proto = {
+	.func		= bpf_map_lookup_elem,
+	.gpl_only	= false,
+	.pkt_access	= true,
+	.ret_type	= RET_PTR_TO_MAP_VALUE_OR_NULL,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_MAP_KEY,
+};
+
+BPF_CALL_4(bpf_map_update_elem, struct bpf_map *, map, void *, key,
+	   void *, value, u64, flags)
+{
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
+	return map->ops->map_update_elem(map, key, value, flags);
+}
+
+const struct bpf_func_proto bpf_map_update_elem_proto = {
+	.func		= bpf_map_update_elem,
+	.gpl_only	= false,
+	.pkt_access	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_MAP_KEY,
+	.arg3_type	= ARG_PTR_TO_MAP_VALUE,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_2(bpf_map_delete_elem, struct bpf_map *, map, void *, key)
+{
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
+	return map->ops->map_delete_elem(map, key);
+}
+
+const struct bpf_func_proto bpf_map_delete_elem_proto = {
+	.func		= bpf_map_delete_elem,
+	.gpl_only	= false,
+	.pkt_access	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_MAP_KEY,
+};
+
+BPF_CALL_3(bpf_map_push_elem, struct bpf_map *, map, void *, value, u64, flags)
+{
+	return map->ops->map_push_elem(map, value, flags);
+}
+
+const struct bpf_func_proto bpf_map_push_elem_proto = {
+	.func		= bpf_map_push_elem,
+	.gpl_only	= false,
+	.pkt_access	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_MAP_VALUE,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value)
+{
+	return map->ops->map_pop_elem(map, value);
+}
+
+const struct bpf_func_proto bpf_map_pop_elem_proto = {
+	.func		= bpf_map_pop_elem,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_MAP_VALUE | MEM_UNINIT,
+};
+
+BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void *, value)
+{
+	return map->ops->map_peek_elem(map, value);
+}
+
+const struct bpf_func_proto bpf_map_peek_elem_proto = {
+	.func		= bpf_map_peek_elem,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_MAP_VALUE | MEM_UNINIT,
+};
+
+BPF_CALL_3(bpf_map_lookup_percpu_elem, struct bpf_map *, map, void *, key, u32, cpu)
+{
+	WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
+	return (unsigned long) map->ops->map_lookup_percpu_elem(map, key, cpu);
+}
+
+const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto = {
+	.func		= bpf_map_lookup_percpu_elem,
+	.gpl_only	= false,
+	.pkt_access	= true,
+	.ret_type	= RET_PTR_TO_MAP_VALUE_OR_NULL,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_MAP_KEY,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+const struct bpf_func_proto bpf_get_prandom_u32_proto = {
+	.func		= bpf_user_rnd_u32,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_0(bpf_get_smp_processor_id)
+{
+	return smp_processor_id();
+}
+
+const struct bpf_func_proto bpf_get_smp_processor_id_proto = {
+	.func		= bpf_get_smp_processor_id,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_0(bpf_get_numa_node_id)
+{
+	return numa_node_id();
+}
+
+const struct bpf_func_proto bpf_get_numa_node_id_proto = {
+	.func		= bpf_get_numa_node_id,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_0(bpf_ktime_get_ns)
+{
+	/* NMI safe access to clock monotonic */
+	return ktime_get_mono_fast_ns();
+}
+
+const struct bpf_func_proto bpf_ktime_get_ns_proto = {
+	.func		= bpf_ktime_get_ns,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_0(bpf_ktime_get_boot_ns)
+{
+	/* NMI safe access to clock boottime */
+	return ktime_get_boot_fast_ns();
+}
+
+const struct bpf_func_proto bpf_ktime_get_boot_ns_proto = {
+	.func		= bpf_ktime_get_boot_ns,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_0(bpf_ktime_get_coarse_ns)
+{
+	return ktime_get_coarse_ns();
+}
+
+const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto = {
+	.func		= bpf_ktime_get_coarse_ns,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_0(bpf_ktime_get_tai_ns)
+{
+	/* NMI safe access to clock tai */
+	return ktime_get_tai_fast_ns();
+}
+
+const struct bpf_func_proto bpf_ktime_get_tai_ns_proto = {
+	.func		= bpf_ktime_get_tai_ns,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_0(bpf_get_current_pid_tgid)
+{
+	struct task_struct *task = current;
+
+	if (unlikely(!task))
+		return -EINVAL;
+
+	return (u64) task->tgid << 32 | task->pid;
+}
+
+const struct bpf_func_proto bpf_get_current_pid_tgid_proto = {
+	.func		= bpf_get_current_pid_tgid,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_0(bpf_get_current_uid_gid)
+{
+	struct task_struct *task = current;
+	kuid_t uid;
+	kgid_t gid;
+
+	if (unlikely(!task))
+		return -EINVAL;
+
+	current_uid_gid(&uid, &gid);
+	return (u64) from_kgid(&init_user_ns, gid) << 32 |
+		     from_kuid(&init_user_ns, uid);
+}
+
+const struct bpf_func_proto bpf_get_current_uid_gid_proto = {
+	.func		= bpf_get_current_uid_gid,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_2(bpf_get_current_comm, char *, buf, u32, size)
+{
+	struct task_struct *task = current;
+
+	if (unlikely(!task))
+		goto err_clear;
+
+	/* Verifier guarantees that size > 0 */
+	strscpy(buf, task->comm, size);
+	return 0;
+err_clear:
+	memset(buf, 0, size);
+	return -EINVAL;
+}
+
+const struct bpf_func_proto bpf_get_current_comm_proto = {
+	.func		= bpf_get_current_comm,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg2_type	= ARG_CONST_SIZE,
+};
+
+#if defined(CONFIG_QUEUED_SPINLOCKS) || defined(CONFIG_BPF_ARCH_SPINLOCK)
+
+static inline void __bpf_spin_lock(struct bpf_spin_lock *lock)
+{
+	arch_spinlock_t *l = (void *)lock;
+	union {
+		__u32 val;
+		arch_spinlock_t lock;
+	} u = { .lock = __ARCH_SPIN_LOCK_UNLOCKED };
+
+	compiletime_assert(u.val == 0, "__ARCH_SPIN_LOCK_UNLOCKED not 0");
+	BUILD_BUG_ON(sizeof(*l) != sizeof(__u32));
+	BUILD_BUG_ON(sizeof(*lock) != sizeof(__u32));
+	arch_spin_lock(l);
+}
+
+static inline void __bpf_spin_unlock(struct bpf_spin_lock *lock)
+{
+	arch_spinlock_t *l = (void *)lock;
+
+	arch_spin_unlock(l);
+}
+
+#else
+
+static inline void __bpf_spin_lock(struct bpf_spin_lock *lock)
+{
+	atomic_t *l = (void *)lock;
+
+	BUILD_BUG_ON(sizeof(*l) != sizeof(*lock));
+	do {
+		atomic_cond_read_relaxed(l, !VAL);
+	} while (atomic_xchg(l, 1));
+}
+
+static inline void __bpf_spin_unlock(struct bpf_spin_lock *lock)
+{
+	atomic_t *l = (void *)lock;
+
+	atomic_set_release(l, 0);
+}
+
+#endif
+
+static DEFINE_PER_CPU(unsigned long, irqsave_flags);
+
+static inline void __bpf_spin_lock_irqsave(struct bpf_spin_lock *lock)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__bpf_spin_lock(lock);
+	__this_cpu_write(irqsave_flags, flags);
+}
+
+notrace BPF_CALL_1(bpf_spin_lock, struct bpf_spin_lock *, lock)
+{
+	__bpf_spin_lock_irqsave(lock);
+	return 0;
+}
+
+const struct bpf_func_proto bpf_spin_lock_proto = {
+	.func		= bpf_spin_lock,
+	.gpl_only	= false,
+	.ret_type	= RET_VOID,
+	.arg1_type	= ARG_PTR_TO_SPIN_LOCK,
+};
+
+static inline void __bpf_spin_unlock_irqrestore(struct bpf_spin_lock *lock)
+{
+	unsigned long flags;
+
+	flags = __this_cpu_read(irqsave_flags);
+	__bpf_spin_unlock(lock);
+	local_irq_restore(flags);
+}
+
+notrace BPF_CALL_1(bpf_spin_unlock, struct bpf_spin_lock *, lock)
+{
+	__bpf_spin_unlock_irqrestore(lock);
+	return 0;
+}
+
+const struct bpf_func_proto bpf_spin_unlock_proto = {
+	.func		= bpf_spin_unlock,
+	.gpl_only	= false,
+	.ret_type	= RET_VOID,
+	.arg1_type	= ARG_PTR_TO_SPIN_LOCK,
+};
+
+void copy_map_value_locked(struct bpf_map *map, void *dst, void *src,
+			   bool lock_src)
+{
+	struct bpf_spin_lock *lock;
+
+	if (lock_src)
+		lock = src + map->spin_lock_off;
+	else
+		lock = dst + map->spin_lock_off;
+	preempt_disable();
+	__bpf_spin_lock_irqsave(lock);
+	copy_map_value(map, dst, src);
+	__bpf_spin_unlock_irqrestore(lock);
+	preempt_enable();
+}
+
+BPF_CALL_0(bpf_jiffies64)
+{
+	return get_jiffies_64();
+}
+
+const struct bpf_func_proto bpf_jiffies64_proto = {
+	.func		= bpf_jiffies64,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+#ifdef CONFIG_CGROUPS
+BPF_CALL_0(bpf_get_current_cgroup_id)
+{
+	struct cgroup *cgrp;
+	u64 cgrp_id;
+
+	rcu_read_lock();
+	cgrp = task_dfl_cgroup(current);
+	cgrp_id = cgroup_id(cgrp);
+	rcu_read_unlock();
+
+	return cgrp_id;
+}
+
+const struct bpf_func_proto bpf_get_current_cgroup_id_proto = {
+	.func		= bpf_get_current_cgroup_id,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_1(bpf_get_current_ancestor_cgroup_id, int, ancestor_level)
+{
+	struct cgroup *cgrp;
+	struct cgroup *ancestor;
+	u64 cgrp_id;
+
+	rcu_read_lock();
+	cgrp = task_dfl_cgroup(current);
+	ancestor = cgroup_ancestor(cgrp, ancestor_level);
+	cgrp_id = ancestor ? cgroup_id(ancestor) : 0;
+	rcu_read_unlock();
+
+	return cgrp_id;
+}
+
+const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto = {
+	.func		= bpf_get_current_ancestor_cgroup_id,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_ANYTHING,
+};
+#endif /* CONFIG_CGROUPS */
+
+#define BPF_STRTOX_BASE_MASK 0x1F
+
+static int __bpf_strtoull(const char *buf, size_t buf_len, u64 flags,
+			  unsigned long long *res, bool *is_negative)
+{
+	unsigned int base = flags & BPF_STRTOX_BASE_MASK;
+	const char *cur_buf = buf;
+	size_t cur_len = buf_len;
+	unsigned int consumed;
+	size_t val_len;
+	char str[64];
+
+	if (!buf || !buf_len || !res || !is_negative)
+		return -EINVAL;
+
+	if (base != 0 && base != 8 && base != 10 && base != 16)
+		return -EINVAL;
+
+	if (flags & ~BPF_STRTOX_BASE_MASK)
+		return -EINVAL;
+
+	while (cur_buf < buf + buf_len && isspace(*cur_buf))
+		++cur_buf;
+
+	*is_negative = (cur_buf < buf + buf_len && *cur_buf == '-');
+	if (*is_negative)
+		++cur_buf;
+
+	consumed = cur_buf - buf;
+	cur_len -= consumed;
+	if (!cur_len)
+		return -EINVAL;
+
+	cur_len = min(cur_len, sizeof(str) - 1);
+	memcpy(str, cur_buf, cur_len);
+	str[cur_len] = '\0';
+	cur_buf = str;
+
+	cur_buf = _parse_integer_fixup_radix(cur_buf, &base);
+	val_len = _parse_integer(cur_buf, base, res);
+
+	if (val_len & KSTRTOX_OVERFLOW)
+		return -ERANGE;
+
+	if (val_len == 0)
+		return -EINVAL;
+
+	cur_buf += val_len;
+	consumed += cur_buf - str;
+
+	return consumed;
+}
+
+static int __bpf_strtoll(const char *buf, size_t buf_len, u64 flags,
+			 long long *res)
+{
+	unsigned long long _res;
+	bool is_negative;
+	int err;
+
+	err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative);
+	if (err < 0)
+		return err;
+	if (is_negative) {
+		if ((long long)-_res > 0)
+			return -ERANGE;
+		*res = -_res;
+	} else {
+		if ((long long)_res < 0)
+			return -ERANGE;
+		*res = _res;
+	}
+	return err;
+}
+
+BPF_CALL_4(bpf_strtol, const char *, buf, size_t, buf_len, u64, flags,
+	   long *, res)
+{
+	long long _res;
+	int err;
+
+	err = __bpf_strtoll(buf, buf_len, flags, &_res);
+	if (err < 0)
+		return err;
+	if (_res != (long)_res)
+		return -ERANGE;
+	*res = _res;
+	return err;
+}
+
+const struct bpf_func_proto bpf_strtol_proto = {
+	.func		= bpf_strtol,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg2_type	= ARG_CONST_SIZE,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_PTR_TO_LONG,
+};
+
+BPF_CALL_4(bpf_strtoul, const char *, buf, size_t, buf_len, u64, flags,
+	   unsigned long *, res)
+{
+	unsigned long long _res;
+	bool is_negative;
+	int err;
+
+	err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative);
+	if (err < 0)
+		return err;
+	if (is_negative)
+		return -EINVAL;
+	if (_res != (unsigned long)_res)
+		return -ERANGE;
+	*res = _res;
+	return err;
+}
+
+const struct bpf_func_proto bpf_strtoul_proto = {
+	.func		= bpf_strtoul,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg2_type	= ARG_CONST_SIZE,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_PTR_TO_LONG,
+};
+
+BPF_CALL_3(bpf_strncmp, const char *, s1, u32, s1_sz, const char *, s2)
+{
+	return strncmp(s1, s2, s1_sz);
+}
+
+static const struct bpf_func_proto bpf_strncmp_proto = {
+	.func		= bpf_strncmp,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_MEM,
+	.arg2_type	= ARG_CONST_SIZE,
+	.arg3_type	= ARG_PTR_TO_CONST_STR,
+};
+
+BPF_CALL_4(bpf_get_ns_current_pid_tgid, u64, dev, u64, ino,
+	   struct bpf_pidns_info *, nsdata, u32, size)
+{
+	struct task_struct *task = current;
+	struct pid_namespace *pidns;
+	int err = -EINVAL;
+
+	if (unlikely(size != sizeof(struct bpf_pidns_info)))
+		goto clear;
+
+	if (unlikely((u64)(dev_t)dev != dev))
+		goto clear;
+
+	if (unlikely(!task))
+		goto clear;
+
+	pidns = task_active_pid_ns(task);
+	if (unlikely(!pidns)) {
+		err = -ENOENT;
+		goto clear;
+	}
+
+	if (!ns_match(&pidns->ns, (dev_t)dev, ino))
+		goto clear;
+
+	nsdata->pid = task_pid_nr_ns(task, pidns);
+	nsdata->tgid = task_tgid_nr_ns(task, pidns);
+	return 0;
+clear:
+	memset((void *)nsdata, 0, (size_t) size);
+	return err;
+}
+
+const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto = {
+	.func		= bpf_get_ns_current_pid_tgid,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_ANYTHING,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type      = ARG_PTR_TO_UNINIT_MEM,
+	.arg4_type      = ARG_CONST_SIZE,
+};
+
+static const struct bpf_func_proto bpf_get_raw_smp_processor_id_proto = {
+	.func		= bpf_get_raw_cpu_id,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_5(bpf_event_output_data, void *, ctx, struct bpf_map *, map,
+	   u64, flags, void *, data, u64, size)
+{
+	if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
+		return -EINVAL;
+
+	return bpf_event_output(map, flags, data, size, NULL, 0, NULL);
+}
+
+const struct bpf_func_proto bpf_event_output_data_proto =  {
+	.func		= bpf_event_output_data,
+	.gpl_only       = true,
+	.ret_type       = RET_INTEGER,
+	.arg1_type      = ARG_PTR_TO_CTX,
+	.arg2_type      = ARG_CONST_MAP_PTR,
+	.arg3_type      = ARG_ANYTHING,
+	.arg4_type      = ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg5_type      = ARG_CONST_SIZE_OR_ZERO,
+};
+
+BPF_CALL_3(bpf_copy_from_user, void *, dst, u32, size,
+	   const void __user *, user_ptr)
+{
+	int ret = copy_from_user(dst, user_ptr, size);
+
+	if (unlikely(ret)) {
+		memset(dst, 0, size);
+		ret = -EFAULT;
+	}
+
+	return ret;
+}
+
+const struct bpf_func_proto bpf_copy_from_user_proto = {
+	.func		= bpf_copy_from_user,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_5(bpf_copy_from_user_task, void *, dst, u32, size,
+	   const void __user *, user_ptr, struct task_struct *, tsk, u64, flags)
+{
+	int ret;
+
+	/* flags is not used yet */
+	if (unlikely(flags))
+		return -EINVAL;
+
+	if (unlikely(!size))
+		return 0;
+
+	ret = access_process_vm(tsk, (unsigned long)user_ptr, dst, size, 0);
+	if (ret == size)
+		return 0;
+
+	memset(dst, 0, size);
+	/* Return -EFAULT for partial read */
+	return ret < 0 ? ret : -EFAULT;
+}
+
+const struct bpf_func_proto bpf_copy_from_user_task_proto = {
+	.func		= bpf_copy_from_user_task,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_PTR_TO_BTF_ID,
+	.arg4_btf_id	= &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
+	.arg5_type	= ARG_ANYTHING
+};
+
+BPF_CALL_2(bpf_per_cpu_ptr, const void *, ptr, u32, cpu)
+{
+	if (cpu >= nr_cpu_ids)
+		return (unsigned long)NULL;
+
+	return (unsigned long)per_cpu_ptr((const void __percpu *)ptr, cpu);
+}
+
+const struct bpf_func_proto bpf_per_cpu_ptr_proto = {
+	.func		= bpf_per_cpu_ptr,
+	.gpl_only	= false,
+	.ret_type	= RET_PTR_TO_MEM_OR_BTF_ID | PTR_MAYBE_NULL | MEM_RDONLY,
+	.arg1_type	= ARG_PTR_TO_PERCPU_BTF_ID,
+	.arg2_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_1(bpf_this_cpu_ptr, const void *, percpu_ptr)
+{
+	return (unsigned long)this_cpu_ptr((const void __percpu *)percpu_ptr);
+}
+
+const struct bpf_func_proto bpf_this_cpu_ptr_proto = {
+	.func		= bpf_this_cpu_ptr,
+	.gpl_only	= false,
+	.ret_type	= RET_PTR_TO_MEM_OR_BTF_ID | MEM_RDONLY,
+	.arg1_type	= ARG_PTR_TO_PERCPU_BTF_ID,
+};
+
+static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
+		size_t bufsz)
+{
+	void __user *user_ptr = (__force void __user *)unsafe_ptr;
+
+	buf[0] = 0;
+
+	switch (fmt_ptype) {
+	case 's':
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+		if ((unsigned long)unsafe_ptr < TASK_SIZE)
+			return strncpy_from_user_nofault(buf, user_ptr, bufsz);
+		fallthrough;
+#endif
+	case 'k':
+		return strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz);
+	case 'u':
+		return strncpy_from_user_nofault(buf, user_ptr, bufsz);
+	}
+
+	return -EINVAL;
+}
+
+/* Per-cpu temp buffers used by printf-like helpers to store the bprintf binary
+ * arguments representation.
+ */
+#define MAX_BPRINTF_BUF_LEN	512
+
+/* Support executing three nested bprintf helper calls on a given CPU */
+#define MAX_BPRINTF_NEST_LEVEL	3
+struct bpf_bprintf_buffers {
+	char tmp_bufs[MAX_BPRINTF_NEST_LEVEL][MAX_BPRINTF_BUF_LEN];
+};
+static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs);
+static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
+
+static int try_get_fmt_tmp_buf(char **tmp_buf)
+{
+	struct bpf_bprintf_buffers *bufs;
+	int nest_level;
+
+	preempt_disable();
+	nest_level = this_cpu_inc_return(bpf_bprintf_nest_level);
+	if (WARN_ON_ONCE(nest_level > MAX_BPRINTF_NEST_LEVEL)) {
+		this_cpu_dec(bpf_bprintf_nest_level);
+		preempt_enable();
+		return -EBUSY;
+	}
+	bufs = this_cpu_ptr(&bpf_bprintf_bufs);
+	*tmp_buf = bufs->tmp_bufs[nest_level - 1];
+
+	return 0;
+}
+
+void bpf_bprintf_cleanup(void)
+{
+	if (this_cpu_read(bpf_bprintf_nest_level)) {
+		this_cpu_dec(bpf_bprintf_nest_level);
+		preempt_enable();
+	}
+}
+
+/*
+ * bpf_bprintf_prepare - Generic pass on format strings for bprintf-like helpers
+ *
+ * Returns a negative value if fmt is an invalid format string or 0 otherwise.
+ *
+ * This can be used in two ways:
+ * - Format string verification only: when bin_args is NULL
+ * - Arguments preparation: in addition to the above verification, it writes in
+ *   bin_args a binary representation of arguments usable by bstr_printf where
+ *   pointers from BPF have been sanitized.
+ *
+ * In argument preparation mode, if 0 is returned, safe temporary buffers are
+ * allocated and bpf_bprintf_cleanup should be called to free them after use.
+ */
+int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
+			u32 **bin_args, u32 num_args)
+{
+	char *unsafe_ptr = NULL, *tmp_buf = NULL, *tmp_buf_end, *fmt_end;
+	size_t sizeof_cur_arg, sizeof_cur_ip;
+	int err, i, num_spec = 0;
+	u64 cur_arg;
+	char fmt_ptype, cur_ip[16], ip_spec[] = "%pXX";
+
+	fmt_end = strnchr(fmt, fmt_size, 0);
+	if (!fmt_end)
+		return -EINVAL;
+	fmt_size = fmt_end - fmt;
+
+	if (bin_args) {
+		if (num_args && try_get_fmt_tmp_buf(&tmp_buf))
+			return -EBUSY;
+
+		tmp_buf_end = tmp_buf + MAX_BPRINTF_BUF_LEN;
+		*bin_args = (u32 *)tmp_buf;
+	}
+
+	for (i = 0; i < fmt_size; i++) {
+		if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		if (fmt[i] != '%')
+			continue;
+
+		if (fmt[i + 1] == '%') {
+			i++;
+			continue;
+		}
+
+		if (num_spec >= num_args) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		/* The string is zero-terminated so if fmt[i] != 0, we can
+		 * always access fmt[i + 1], in the worst case it will be a 0
+		 */
+		i++;
+
+		/* skip optional "[0 +-][num]" width formatting field */
+		while (fmt[i] == '0' || fmt[i] == '+'  || fmt[i] == '-' ||
+		       fmt[i] == ' ')
+			i++;
+		if (fmt[i] >= '1' && fmt[i] <= '9') {
+			i++;
+			while (fmt[i] >= '0' && fmt[i] <= '9')
+				i++;
+		}
+
+		if (fmt[i] == 'p') {
+			sizeof_cur_arg = sizeof(long);
+
+			if ((fmt[i + 1] == 'k' || fmt[i + 1] == 'u') &&
+			    fmt[i + 2] == 's') {
+				fmt_ptype = fmt[i + 1];
+				i += 2;
+				goto fmt_str;
+			}
+
+			if (fmt[i + 1] == 0 || isspace(fmt[i + 1]) ||
+			    ispunct(fmt[i + 1]) || fmt[i + 1] == 'K' ||
+			    fmt[i + 1] == 'x' || fmt[i + 1] == 's' ||
+			    fmt[i + 1] == 'S') {
+				/* just kernel pointers */
+				if (tmp_buf)
+					cur_arg = raw_args[num_spec];
+				i++;
+				goto nocopy_fmt;
+			}
+
+			if (fmt[i + 1] == 'B') {
+				if (tmp_buf)  {
+					err = snprintf(tmp_buf,
+						       (tmp_buf_end - tmp_buf),
+						       "%pB",
+						       (void *)(long)raw_args[num_spec]);
+					tmp_buf += (err + 1);
+				}
+
+				i++;
+				num_spec++;
+				continue;
+			}
+
+			/* only support "%pI4", "%pi4", "%pI6" and "%pi6". */
+			if ((fmt[i + 1] != 'i' && fmt[i + 1] != 'I') ||
+			    (fmt[i + 2] != '4' && fmt[i + 2] != '6')) {
+				err = -EINVAL;
+				goto out;
+			}
+
+			i += 2;
+			if (!tmp_buf)
+				goto nocopy_fmt;
+
+			sizeof_cur_ip = (fmt[i] == '4') ? 4 : 16;
+			if (tmp_buf_end - tmp_buf < sizeof_cur_ip) {
+				err = -ENOSPC;
+				goto out;
+			}
+
+			unsafe_ptr = (char *)(long)raw_args[num_spec];
+			err = copy_from_kernel_nofault(cur_ip, unsafe_ptr,
+						       sizeof_cur_ip);
+			if (err < 0)
+				memset(cur_ip, 0, sizeof_cur_ip);
+
+			/* hack: bstr_printf expects IP addresses to be
+			 * pre-formatted as strings, ironically, the easiest way
+			 * to do that is to call snprintf.
+			 */
+			ip_spec[2] = fmt[i - 1];
+			ip_spec[3] = fmt[i];
+			err = snprintf(tmp_buf, tmp_buf_end - tmp_buf,
+				       ip_spec, &cur_ip);
+
+			tmp_buf += err + 1;
+			num_spec++;
+
+			continue;
+		} else if (fmt[i] == 's') {
+			fmt_ptype = fmt[i];
+fmt_str:
+			if (fmt[i + 1] != 0 &&
+			    !isspace(fmt[i + 1]) &&
+			    !ispunct(fmt[i + 1])) {
+				err = -EINVAL;
+				goto out;
+			}
+
+			if (!tmp_buf)
+				goto nocopy_fmt;
+
+			if (tmp_buf_end == tmp_buf) {
+				err = -ENOSPC;
+				goto out;
+			}
+
+			unsafe_ptr = (char *)(long)raw_args[num_spec];
+			err = bpf_trace_copy_string(tmp_buf, unsafe_ptr,
+						    fmt_ptype,
+						    tmp_buf_end - tmp_buf);
+			if (err < 0) {
+				tmp_buf[0] = '\0';
+				err = 1;
+			}
+
+			tmp_buf += err;
+			num_spec++;
+
+			continue;
+		} else if (fmt[i] == 'c') {
+			if (!tmp_buf)
+				goto nocopy_fmt;
+
+			if (tmp_buf_end == tmp_buf) {
+				err = -ENOSPC;
+				goto out;
+			}
+
+			*tmp_buf = raw_args[num_spec];
+			tmp_buf++;
+			num_spec++;
+
+			continue;
+		}
+
+		sizeof_cur_arg = sizeof(int);
+
+		if (fmt[i] == 'l') {
+			sizeof_cur_arg = sizeof(long);
+			i++;
+		}
+		if (fmt[i] == 'l') {
+			sizeof_cur_arg = sizeof(long long);
+			i++;
+		}
+
+		if (fmt[i] != 'i' && fmt[i] != 'd' && fmt[i] != 'u' &&
+		    fmt[i] != 'x' && fmt[i] != 'X') {
+			err = -EINVAL;
+			goto out;
+		}
+
+		if (tmp_buf)
+			cur_arg = raw_args[num_spec];
+nocopy_fmt:
+		if (tmp_buf) {
+			tmp_buf = PTR_ALIGN(tmp_buf, sizeof(u32));
+			if (tmp_buf_end - tmp_buf < sizeof_cur_arg) {
+				err = -ENOSPC;
+				goto out;
+			}
+
+			if (sizeof_cur_arg == 8) {
+				*(u32 *)tmp_buf = *(u32 *)&cur_arg;
+				*(u32 *)(tmp_buf + 4) = *((u32 *)&cur_arg + 1);
+			} else {
+				*(u32 *)tmp_buf = (u32)(long)cur_arg;
+			}
+			tmp_buf += sizeof_cur_arg;
+		}
+		num_spec++;
+	}
+
+	err = 0;
+out:
+	if (err)
+		bpf_bprintf_cleanup();
+	return err;
+}
+
+BPF_CALL_5(bpf_snprintf, char *, str, u32, str_size, char *, fmt,
+	   const void *, data, u32, data_len)
+{
+	int err, num_args;
+	u32 *bin_args;
+
+	if (data_len % 8 || data_len > MAX_BPRINTF_VARARGS * 8 ||
+	    (data_len && !data))
+		return -EINVAL;
+	num_args = data_len / 8;
+
+	/* ARG_PTR_TO_CONST_STR guarantees that fmt is zero-terminated so we
+	 * can safely give an unbounded size.
+	 */
+	err = bpf_bprintf_prepare(fmt, UINT_MAX, data, &bin_args, num_args);
+	if (err < 0)
+		return err;
+
+	err = bstr_printf(str, str_size, fmt, bin_args);
+
+	bpf_bprintf_cleanup();
+
+	return err + 1;
+}
+
+const struct bpf_func_proto bpf_snprintf_proto = {
+	.func		= bpf_snprintf,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_MEM_OR_NULL,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg3_type	= ARG_PTR_TO_CONST_STR,
+	.arg4_type	= ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY,
+	.arg5_type	= ARG_CONST_SIZE_OR_ZERO,
+};
+
+/* BPF map elements can contain 'struct bpf_timer'.
+ * Such map owns all of its BPF timers.
+ * 'struct bpf_timer' is allocated as part of map element allocation
+ * and it's zero initialized.
+ * That space is used to keep 'struct bpf_timer_kern'.
+ * bpf_timer_init() allocates 'struct bpf_hrtimer', inits hrtimer, and
+ * remembers 'struct bpf_map *' pointer it's part of.
+ * bpf_timer_set_callback() increments prog refcnt and assign bpf callback_fn.
+ * bpf_timer_start() arms the timer.
+ * If user space reference to a map goes to zero at this point
+ * ops->map_release_uref callback is responsible for cancelling the timers,
+ * freeing their memory, and decrementing prog's refcnts.
+ * bpf_timer_cancel() cancels the timer and decrements prog's refcnt.
+ * Inner maps can contain bpf timers as well. ops->map_release_uref is
+ * freeing the timers when inner map is replaced or deleted by user space.
+ */
+struct bpf_hrtimer {
+	struct hrtimer timer;
+	struct bpf_map *map;
+	struct bpf_prog *prog;
+	void __rcu *callback_fn;
+	void *value;
+};
+
+/* the actual struct hidden inside uapi struct bpf_timer */
+struct bpf_timer_kern {
+	struct bpf_hrtimer *timer;
+	/* bpf_spin_lock is used here instead of spinlock_t to make
+	 * sure that it always fits into space reserved by struct bpf_timer
+	 * regardless of LOCKDEP and spinlock debug flags.
+	 */
+	struct bpf_spin_lock lock;
+} __attribute__((aligned(8)));
+
+static DEFINE_PER_CPU(struct bpf_hrtimer *, hrtimer_running);
+
+static enum hrtimer_restart bpf_timer_cb(struct hrtimer *hrtimer)
+{
+	struct bpf_hrtimer *t = container_of(hrtimer, struct bpf_hrtimer, timer);
+	struct bpf_map *map = t->map;
+	void *value = t->value;
+	bpf_callback_t callback_fn;
+	void *key;
+	u32 idx;
+
+	BTF_TYPE_EMIT(struct bpf_timer);
+	callback_fn = rcu_dereference_check(t->callback_fn, rcu_read_lock_bh_held());
+	if (!callback_fn)
+		goto out;
+
+	/* bpf_timer_cb() runs in hrtimer_run_softirq. It doesn't migrate and
+	 * cannot be preempted by another bpf_timer_cb() on the same cpu.
+	 * Remember the timer this callback is servicing to prevent
+	 * deadlock if callback_fn() calls bpf_timer_cancel() or
+	 * bpf_map_delete_elem() on the same timer.
+	 */
+	this_cpu_write(hrtimer_running, t);
+	if (map->map_type == BPF_MAP_TYPE_ARRAY) {
+		struct bpf_array *array = container_of(map, struct bpf_array, map);
+
+		/* compute the key */
+		idx = ((char *)value - array->value) / array->elem_size;
+		key = &idx;
+	} else { /* hash or lru */
+		key = value - round_up(map->key_size, 8);
+	}
+
+	callback_fn((u64)(long)map, (u64)(long)key, (u64)(long)value, 0, 0);
+	/* The verifier checked that return value is zero. */
+
+	this_cpu_write(hrtimer_running, NULL);
+out:
+	return HRTIMER_NORESTART;
+}
+
+BPF_CALL_3(bpf_timer_init, struct bpf_timer_kern *, timer, struct bpf_map *, map,
+	   u64, flags)
+{
+	clockid_t clockid = flags & (MAX_CLOCKS - 1);
+	struct bpf_hrtimer *t;
+	int ret = 0;
+
+	BUILD_BUG_ON(MAX_CLOCKS != 16);
+	BUILD_BUG_ON(sizeof(struct bpf_timer_kern) > sizeof(struct bpf_timer));
+	BUILD_BUG_ON(__alignof__(struct bpf_timer_kern) != __alignof__(struct bpf_timer));
+
+	if (in_nmi())
+		return -EOPNOTSUPP;
+
+	if (flags >= MAX_CLOCKS ||
+	    /* similar to timerfd except _ALARM variants are not supported */
+	    (clockid != CLOCK_MONOTONIC &&
+	     clockid != CLOCK_REALTIME &&
+	     clockid != CLOCK_BOOTTIME))
+		return -EINVAL;
+	__bpf_spin_lock_irqsave(&timer->lock);
+	t = timer->timer;
+	if (t) {
+		ret = -EBUSY;
+		goto out;
+	}
+	/* allocate hrtimer via map_kmalloc to use memcg accounting */
+	t = bpf_map_kmalloc_node(map, sizeof(*t), GFP_ATOMIC, map->numa_node);
+	if (!t) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	t->value = (void *)timer - map->timer_off;
+	t->map = map;
+	t->prog = NULL;
+	rcu_assign_pointer(t->callback_fn, NULL);
+	hrtimer_init(&t->timer, clockid, HRTIMER_MODE_REL_SOFT);
+	t->timer.function = bpf_timer_cb;
+	WRITE_ONCE(timer->timer, t);
+	/* Guarantee the order between timer->timer and map->usercnt. So
+	 * when there are concurrent uref release and bpf timer init, either
+	 * bpf_timer_cancel_and_free() called by uref release reads a no-NULL
+	 * timer or atomic64_read() below returns a zero usercnt.
+	 */
+	smp_mb();
+	if (!atomic64_read(&map->usercnt)) {
+		/* maps with timers must be either held by user space
+		 * or pinned in bpffs.
+		 */
+		WRITE_ONCE(timer->timer, NULL);
+		kfree(t);
+		ret = -EPERM;
+	}
+out:
+	__bpf_spin_unlock_irqrestore(&timer->lock);
+	return ret;
+}
+
+static const struct bpf_func_proto bpf_timer_init_proto = {
+	.func		= bpf_timer_init,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_TIMER,
+	.arg2_type	= ARG_CONST_MAP_PTR,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_3(bpf_timer_set_callback, struct bpf_timer_kern *, timer, void *, callback_fn,
+	   struct bpf_prog_aux *, aux)
+{
+	struct bpf_prog *prev, *prog = aux->prog;
+	struct bpf_hrtimer *t;
+	int ret = 0;
+
+	if (in_nmi())
+		return -EOPNOTSUPP;
+	__bpf_spin_lock_irqsave(&timer->lock);
+	t = timer->timer;
+	if (!t) {
+		ret = -EINVAL;
+		goto out;
+	}
+	if (!atomic64_read(&t->map->usercnt)) {
+		/* maps with timers must be either held by user space
+		 * or pinned in bpffs. Otherwise timer might still be
+		 * running even when bpf prog is detached and user space
+		 * is gone, since map_release_uref won't ever be called.
+		 */
+		ret = -EPERM;
+		goto out;
+	}
+	prev = t->prog;
+	if (prev != prog) {
+		/* Bump prog refcnt once. Every bpf_timer_set_callback()
+		 * can pick different callback_fn-s within the same prog.
+		 */
+		prog = bpf_prog_inc_not_zero(prog);
+		if (IS_ERR(prog)) {
+			ret = PTR_ERR(prog);
+			goto out;
+		}
+		if (prev)
+			/* Drop prev prog refcnt when swapping with new prog */
+			bpf_prog_put(prev);
+		t->prog = prog;
+	}
+	rcu_assign_pointer(t->callback_fn, callback_fn);
+out:
+	__bpf_spin_unlock_irqrestore(&timer->lock);
+	return ret;
+}
+
+static const struct bpf_func_proto bpf_timer_set_callback_proto = {
+	.func		= bpf_timer_set_callback,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_TIMER,
+	.arg2_type	= ARG_PTR_TO_FUNC,
+};
+
+BPF_CALL_3(bpf_timer_start, struct bpf_timer_kern *, timer, u64, nsecs, u64, flags)
+{
+	struct bpf_hrtimer *t;
+	int ret = 0;
+
+	if (in_nmi())
+		return -EOPNOTSUPP;
+	if (flags)
+		return -EINVAL;
+	__bpf_spin_lock_irqsave(&timer->lock);
+	t = timer->timer;
+	if (!t || !t->prog) {
+		ret = -EINVAL;
+		goto out;
+	}
+	hrtimer_start(&t->timer, ns_to_ktime(nsecs), HRTIMER_MODE_REL_SOFT);
+out:
+	__bpf_spin_unlock_irqrestore(&timer->lock);
+	return ret;
+}
+
+static const struct bpf_func_proto bpf_timer_start_proto = {
+	.func		= bpf_timer_start,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_TIMER,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+static void drop_prog_refcnt(struct bpf_hrtimer *t)
+{
+	struct bpf_prog *prog = t->prog;
+
+	if (prog) {
+		bpf_prog_put(prog);
+		t->prog = NULL;
+		rcu_assign_pointer(t->callback_fn, NULL);
+	}
+}
+
+BPF_CALL_1(bpf_timer_cancel, struct bpf_timer_kern *, timer)
+{
+	struct bpf_hrtimer *t;
+	int ret = 0;
+
+	if (in_nmi())
+		return -EOPNOTSUPP;
+	__bpf_spin_lock_irqsave(&timer->lock);
+	t = timer->timer;
+	if (!t) {
+		ret = -EINVAL;
+		goto out;
+	}
+	if (this_cpu_read(hrtimer_running) == t) {
+		/* If bpf callback_fn is trying to bpf_timer_cancel()
+		 * its own timer the hrtimer_cancel() will deadlock
+		 * since it waits for callback_fn to finish
+		 */
+		ret = -EDEADLK;
+		goto out;
+	}
+	drop_prog_refcnt(t);
+out:
+	__bpf_spin_unlock_irqrestore(&timer->lock);
+	/* Cancel the timer and wait for associated callback to finish
+	 * if it was running.
+	 */
+	ret = ret ?: hrtimer_cancel(&t->timer);
+	return ret;
+}
+
+static const struct bpf_func_proto bpf_timer_cancel_proto = {
+	.func		= bpf_timer_cancel,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_TIMER,
+};
+
+/* This function is called by map_delete/update_elem for individual element and
+ * by ops->map_release_uref when the user space reference to a map reaches zero.
+ */
+void bpf_timer_cancel_and_free(void *val)
+{
+	struct bpf_timer_kern *timer = val;
+	struct bpf_hrtimer *t;
+
+	/* Performance optimization: read timer->timer without lock first. */
+	if (!READ_ONCE(timer->timer))
+		return;
+
+	__bpf_spin_lock_irqsave(&timer->lock);
+	/* re-read it under lock */
+	t = timer->timer;
+	if (!t)
+		goto out;
+	drop_prog_refcnt(t);
+	/* The subsequent bpf_timer_start/cancel() helpers won't be able to use
+	 * this timer, since it won't be initialized.
+	 */
+	WRITE_ONCE(timer->timer, NULL);
+out:
+	__bpf_spin_unlock_irqrestore(&timer->lock);
+	if (!t)
+		return;
+	/* Cancel the timer and wait for callback to complete if it was running.
+	 * If hrtimer_cancel() can be safely called it's safe to call kfree(t)
+	 * right after for both preallocated and non-preallocated maps.
+	 * The timer->timer = NULL was already done and no code path can
+	 * see address 't' anymore.
+	 *
+	 * Check that bpf_map_delete/update_elem() wasn't called from timer
+	 * callback_fn. In such case don't call hrtimer_cancel() (since it will
+	 * deadlock) and don't call hrtimer_try_to_cancel() (since it will just
+	 * return -1). Though callback_fn is still running on this cpu it's
+	 * safe to do kfree(t) because bpf_timer_cb() read everything it needed
+	 * from 't'. The bpf subprog callback_fn won't be able to access 't',
+	 * since timer->timer = NULL was already done. The timer will be
+	 * effectively cancelled because bpf_timer_cb() will return
+	 * HRTIMER_NORESTART.
+	 */
+	if (this_cpu_read(hrtimer_running) != t)
+		hrtimer_cancel(&t->timer);
+	kfree(t);
+}
+
+BPF_CALL_2(bpf_kptr_xchg, void *, map_value, void *, ptr)
+{
+	unsigned long *kptr = map_value;
+
+	return xchg(kptr, (unsigned long)ptr);
+}
+
+/* Unlike other PTR_TO_BTF_ID helpers the btf_id in bpf_kptr_xchg()
+ * helper is determined dynamically by the verifier. Use BPF_PTR_POISON to
+ * denote type that verifier will determine.
+ */
+static const struct bpf_func_proto bpf_kptr_xchg_proto = {
+	.func         = bpf_kptr_xchg,
+	.gpl_only     = false,
+	.ret_type     = RET_PTR_TO_BTF_ID_OR_NULL,
+	.ret_btf_id   = BPF_PTR_POISON,
+	.arg1_type    = ARG_PTR_TO_KPTR,
+	.arg2_type    = ARG_PTR_TO_BTF_ID_OR_NULL | OBJ_RELEASE,
+	.arg2_btf_id  = BPF_PTR_POISON,
+};
+
+/* Since the upper 8 bits of dynptr->size is reserved, the
+ * maximum supported size is 2^24 - 1.
+ */
+#define DYNPTR_MAX_SIZE	((1UL << 24) - 1)
+#define DYNPTR_TYPE_SHIFT	28
+#define DYNPTR_SIZE_MASK	0xFFFFFF
+#define DYNPTR_RDONLY_BIT	BIT(31)
+
+static bool bpf_dynptr_is_rdonly(struct bpf_dynptr_kern *ptr)
+{
+	return ptr->size & DYNPTR_RDONLY_BIT;
+}
+
+static void bpf_dynptr_set_type(struct bpf_dynptr_kern *ptr, enum bpf_dynptr_type type)
+{
+	ptr->size |= type << DYNPTR_TYPE_SHIFT;
+}
+
+u32 bpf_dynptr_get_size(struct bpf_dynptr_kern *ptr)
+{
+	return ptr->size & DYNPTR_SIZE_MASK;
+}
+
+int bpf_dynptr_check_size(u32 size)
+{
+	return size > DYNPTR_MAX_SIZE ? -E2BIG : 0;
+}
+
+void bpf_dynptr_init(struct bpf_dynptr_kern *ptr, void *data,
+		     enum bpf_dynptr_type type, u32 offset, u32 size)
+{
+	ptr->data = data;
+	ptr->offset = offset;
+	ptr->size = size;
+	bpf_dynptr_set_type(ptr, type);
+}
+
+void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr)
+{
+	memset(ptr, 0, sizeof(*ptr));
+}
+
+static int bpf_dynptr_check_off_len(struct bpf_dynptr_kern *ptr, u32 offset, u32 len)
+{
+	u32 size = bpf_dynptr_get_size(ptr);
+
+	if (len > size || offset > size - len)
+		return -E2BIG;
+
+	return 0;
+}
+
+BPF_CALL_4(bpf_dynptr_from_mem, void *, data, u32, size, u64, flags, struct bpf_dynptr_kern *, ptr)
+{
+	int err;
+
+	BTF_TYPE_EMIT(struct bpf_dynptr);
+
+	err = bpf_dynptr_check_size(size);
+	if (err)
+		goto error;
+
+	/* flags is currently unsupported */
+	if (flags) {
+		err = -EINVAL;
+		goto error;
+	}
+
+	bpf_dynptr_init(ptr, data, BPF_DYNPTR_TYPE_LOCAL, 0, size);
+
+	return 0;
+
+error:
+	bpf_dynptr_set_null(ptr);
+	return err;
+}
+
+static const struct bpf_func_proto bpf_dynptr_from_mem_proto = {
+	.func		= bpf_dynptr_from_mem,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL | MEM_UNINIT,
+};
+
+BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, struct bpf_dynptr_kern *, src,
+	   u32, offset, u64, flags)
+{
+	int err;
+
+	if (!src->data || flags)
+		return -EINVAL;
+
+	err = bpf_dynptr_check_off_len(src, offset, len);
+	if (err)
+		return err;
+
+	memcpy(dst, src->data + src->offset + offset, len);
+
+	return 0;
+}
+
+static const struct bpf_func_proto bpf_dynptr_read_proto = {
+	.func		= bpf_dynptr_read,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg3_type	= ARG_PTR_TO_DYNPTR,
+	.arg4_type	= ARG_ANYTHING,
+	.arg5_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_5(bpf_dynptr_write, struct bpf_dynptr_kern *, dst, u32, offset, void *, src,
+	   u32, len, u64, flags)
+{
+	int err;
+
+	if (!dst->data || flags || bpf_dynptr_is_rdonly(dst))
+		return -EINVAL;
+
+	err = bpf_dynptr_check_off_len(dst, offset, len);
+	if (err)
+		return err;
+
+	memcpy(dst->data + dst->offset + offset, src, len);
+
+	return 0;
+}
+
+static const struct bpf_func_proto bpf_dynptr_write_proto = {
+	.func		= bpf_dynptr_write,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_DYNPTR,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg4_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg5_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_3(bpf_dynptr_data, struct bpf_dynptr_kern *, ptr, u32, offset, u32, len)
+{
+	int err;
+
+	if (!ptr->data)
+		return 0;
+
+	err = bpf_dynptr_check_off_len(ptr, offset, len);
+	if (err)
+		return 0;
+
+	if (bpf_dynptr_is_rdonly(ptr))
+		return 0;
+
+	return (unsigned long)(ptr->data + ptr->offset + offset);
+}
+
+static const struct bpf_func_proto bpf_dynptr_data_proto = {
+	.func		= bpf_dynptr_data,
+	.gpl_only	= false,
+	.ret_type	= RET_PTR_TO_DYNPTR_MEM_OR_NULL,
+	.arg1_type	= ARG_PTR_TO_DYNPTR,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_CONST_ALLOC_SIZE_OR_ZERO,
+};
+
+const struct bpf_func_proto bpf_get_current_task_proto __weak;
+const struct bpf_func_proto bpf_get_current_task_btf_proto __weak;
+const struct bpf_func_proto bpf_probe_read_user_proto __weak;
+const struct bpf_func_proto bpf_probe_read_user_str_proto __weak;
+const struct bpf_func_proto bpf_probe_read_kernel_proto __weak;
+const struct bpf_func_proto bpf_probe_read_kernel_str_proto __weak;
+const struct bpf_func_proto bpf_task_pt_regs_proto __weak;
+
+const struct bpf_func_proto *
+bpf_base_func_proto(enum bpf_func_id func_id)
+{
+	switch (func_id) {
+	case BPF_FUNC_map_lookup_elem:
+		return &bpf_map_lookup_elem_proto;
+	case BPF_FUNC_map_update_elem:
+		return &bpf_map_update_elem_proto;
+	case BPF_FUNC_map_delete_elem:
+		return &bpf_map_delete_elem_proto;
+	case BPF_FUNC_map_push_elem:
+		return &bpf_map_push_elem_proto;
+	case BPF_FUNC_map_pop_elem:
+		return &bpf_map_pop_elem_proto;
+	case BPF_FUNC_map_peek_elem:
+		return &bpf_map_peek_elem_proto;
+	case BPF_FUNC_map_lookup_percpu_elem:
+		return &bpf_map_lookup_percpu_elem_proto;
+	case BPF_FUNC_get_prandom_u32:
+		return &bpf_get_prandom_u32_proto;
+	case BPF_FUNC_get_smp_processor_id:
+		return &bpf_get_raw_smp_processor_id_proto;
+	case BPF_FUNC_get_numa_node_id:
+		return &bpf_get_numa_node_id_proto;
+	case BPF_FUNC_tail_call:
+		return &bpf_tail_call_proto;
+	case BPF_FUNC_ktime_get_ns:
+		return &bpf_ktime_get_ns_proto;
+	case BPF_FUNC_ktime_get_boot_ns:
+		return &bpf_ktime_get_boot_ns_proto;
+	case BPF_FUNC_ktime_get_tai_ns:
+		return &bpf_ktime_get_tai_ns_proto;
+	case BPF_FUNC_ringbuf_output:
+		return &bpf_ringbuf_output_proto;
+	case BPF_FUNC_ringbuf_reserve:
+		return &bpf_ringbuf_reserve_proto;
+	case BPF_FUNC_ringbuf_submit:
+		return &bpf_ringbuf_submit_proto;
+	case BPF_FUNC_ringbuf_discard:
+		return &bpf_ringbuf_discard_proto;
+	case BPF_FUNC_ringbuf_query:
+		return &bpf_ringbuf_query_proto;
+	case BPF_FUNC_strncmp:
+		return &bpf_strncmp_proto;
+	case BPF_FUNC_strtol:
+		return &bpf_strtol_proto;
+	case BPF_FUNC_strtoul:
+		return &bpf_strtoul_proto;
+	default:
+		break;
+	}
+
+	if (!bpf_capable())
+		return NULL;
+
+	switch (func_id) {
+	case BPF_FUNC_spin_lock:
+		return &bpf_spin_lock_proto;
+	case BPF_FUNC_spin_unlock:
+		return &bpf_spin_unlock_proto;
+	case BPF_FUNC_jiffies64:
+		return &bpf_jiffies64_proto;
+	case BPF_FUNC_per_cpu_ptr:
+		return &bpf_per_cpu_ptr_proto;
+	case BPF_FUNC_this_cpu_ptr:
+		return &bpf_this_cpu_ptr_proto;
+	case BPF_FUNC_timer_init:
+		return &bpf_timer_init_proto;
+	case BPF_FUNC_timer_set_callback:
+		return &bpf_timer_set_callback_proto;
+	case BPF_FUNC_timer_start:
+		return &bpf_timer_start_proto;
+	case BPF_FUNC_timer_cancel:
+		return &bpf_timer_cancel_proto;
+	case BPF_FUNC_kptr_xchg:
+		return &bpf_kptr_xchg_proto;
+	case BPF_FUNC_for_each_map_elem:
+		return &bpf_for_each_map_elem_proto;
+	case BPF_FUNC_loop:
+		return &bpf_loop_proto;
+	case BPF_FUNC_user_ringbuf_drain:
+		return &bpf_user_ringbuf_drain_proto;
+	case BPF_FUNC_ringbuf_reserve_dynptr:
+		return &bpf_ringbuf_reserve_dynptr_proto;
+	case BPF_FUNC_ringbuf_submit_dynptr:
+		return &bpf_ringbuf_submit_dynptr_proto;
+	case BPF_FUNC_ringbuf_discard_dynptr:
+		return &bpf_ringbuf_discard_dynptr_proto;
+	case BPF_FUNC_dynptr_from_mem:
+		return &bpf_dynptr_from_mem_proto;
+	case BPF_FUNC_dynptr_read:
+		return &bpf_dynptr_read_proto;
+	case BPF_FUNC_dynptr_write:
+		return &bpf_dynptr_write_proto;
+	case BPF_FUNC_dynptr_data:
+		return &bpf_dynptr_data_proto;
+	default:
+		break;
+	}
+
+	if (!perfmon_capable())
+		return NULL;
+
+	switch (func_id) {
+	case BPF_FUNC_trace_printk:
+		return bpf_get_trace_printk_proto();
+	case BPF_FUNC_get_current_task:
+		return &bpf_get_current_task_proto;
+	case BPF_FUNC_get_current_task_btf:
+		return &bpf_get_current_task_btf_proto;
+	case BPF_FUNC_probe_read_user:
+		return &bpf_probe_read_user_proto;
+	case BPF_FUNC_probe_read_kernel:
+		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
+		       NULL : &bpf_probe_read_kernel_proto;
+	case BPF_FUNC_probe_read_user_str:
+		return &bpf_probe_read_user_str_proto;
+	case BPF_FUNC_probe_read_kernel_str:
+		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
+		       NULL : &bpf_probe_read_kernel_str_proto;
+	case BPF_FUNC_snprintf_btf:
+		return &bpf_snprintf_btf_proto;
+	case BPF_FUNC_snprintf:
+		return &bpf_snprintf_proto;
+	case BPF_FUNC_task_pt_regs:
+		return &bpf_task_pt_regs_proto;
+	case BPF_FUNC_trace_vprintk:
+		return bpf_get_trace_vprintk_proto();
+	default:
+		return NULL;
+	}
+}
+
+BTF_SET8_START(tracing_btf_ids)
+#ifdef CONFIG_KEXEC_CORE
+BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE)
+#endif
+BTF_SET8_END(tracing_btf_ids)
+
+static const struct btf_kfunc_id_set tracing_kfunc_set = {
+	.owner = THIS_MODULE,
+	.set   = &tracing_btf_ids,
+};
+
+static int __init kfunc_init(void)
+{
+	return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &tracing_kfunc_set);
+}
+
+late_initcall(kfunc_init);
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
new file mode 100644
index 000000000..4f841e167
--- /dev/null
+++ b/kernel/bpf/inode.c
@@ -0,0 +1,820 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Minimal file system backend for holding eBPF maps and programs,
+ * used by bpf(2) object pinning.
+ *
+ * Authors:
+ *
+ *	Daniel Borkmann <daniel@iogearbox.net>
+ */
+
+#include <linux/init.h>
+#include <linux/magic.h>
+#include <linux/major.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/fs.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/kdev_t.h>
+#include <linux/filter.h>
+#include <linux/bpf.h>
+#include <linux/bpf_trace.h>
+#include "preload/bpf_preload.h"
+
+enum bpf_type {
+	BPF_TYPE_UNSPEC	= 0,
+	BPF_TYPE_PROG,
+	BPF_TYPE_MAP,
+	BPF_TYPE_LINK,
+};
+
+static void *bpf_any_get(void *raw, enum bpf_type type)
+{
+	switch (type) {
+	case BPF_TYPE_PROG:
+		bpf_prog_inc(raw);
+		break;
+	case BPF_TYPE_MAP:
+		bpf_map_inc_with_uref(raw);
+		break;
+	case BPF_TYPE_LINK:
+		bpf_link_inc(raw);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
+
+	return raw;
+}
+
+static void bpf_any_put(void *raw, enum bpf_type type)
+{
+	switch (type) {
+	case BPF_TYPE_PROG:
+		bpf_prog_put(raw);
+		break;
+	case BPF_TYPE_MAP:
+		bpf_map_put_with_uref(raw);
+		break;
+	case BPF_TYPE_LINK:
+		bpf_link_put(raw);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
+}
+
+static void *bpf_fd_probe_obj(u32 ufd, enum bpf_type *type)
+{
+	void *raw;
+
+	raw = bpf_map_get_with_uref(ufd);
+	if (!IS_ERR(raw)) {
+		*type = BPF_TYPE_MAP;
+		return raw;
+	}
+
+	raw = bpf_prog_get(ufd);
+	if (!IS_ERR(raw)) {
+		*type = BPF_TYPE_PROG;
+		return raw;
+	}
+
+	raw = bpf_link_get_from_fd(ufd);
+	if (!IS_ERR(raw)) {
+		*type = BPF_TYPE_LINK;
+		return raw;
+	}
+
+	return ERR_PTR(-EINVAL);
+}
+
+static const struct inode_operations bpf_dir_iops;
+
+static const struct inode_operations bpf_prog_iops = { };
+static const struct inode_operations bpf_map_iops  = { };
+static const struct inode_operations bpf_link_iops  = { };
+
+static struct inode *bpf_get_inode(struct super_block *sb,
+				   const struct inode *dir,
+				   umode_t mode)
+{
+	struct inode *inode;
+
+	switch (mode & S_IFMT) {
+	case S_IFDIR:
+	case S_IFREG:
+	case S_IFLNK:
+		break;
+	default:
+		return ERR_PTR(-EINVAL);
+	}
+
+	inode = new_inode(sb);
+	if (!inode)
+		return ERR_PTR(-ENOSPC);
+
+	inode->i_ino = get_next_ino();
+	inode->i_atime = current_time(inode);
+	inode->i_mtime = inode->i_atime;
+	inode->i_ctime = inode->i_atime;
+
+	inode_init_owner(&init_user_ns, inode, dir, mode);
+
+	return inode;
+}
+
+static int bpf_inode_type(const struct inode *inode, enum bpf_type *type)
+{
+	*type = BPF_TYPE_UNSPEC;
+	if (inode->i_op == &bpf_prog_iops)
+		*type = BPF_TYPE_PROG;
+	else if (inode->i_op == &bpf_map_iops)
+		*type = BPF_TYPE_MAP;
+	else if (inode->i_op == &bpf_link_iops)
+		*type = BPF_TYPE_LINK;
+	else
+		return -EACCES;
+
+	return 0;
+}
+
+static void bpf_dentry_finalize(struct dentry *dentry, struct inode *inode,
+				struct inode *dir)
+{
+	d_instantiate(dentry, inode);
+	dget(dentry);
+
+	dir->i_mtime = current_time(dir);
+	dir->i_ctime = dir->i_mtime;
+}
+
+static int bpf_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+		     struct dentry *dentry, umode_t mode)
+{
+	struct inode *inode;
+
+	inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFDIR);
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+
+	inode->i_op = &bpf_dir_iops;
+	inode->i_fop = &simple_dir_operations;
+
+	inc_nlink(inode);
+	inc_nlink(dir);
+
+	bpf_dentry_finalize(dentry, inode, dir);
+	return 0;
+}
+
+struct map_iter {
+	void *key;
+	bool done;
+};
+
+static struct map_iter *map_iter(struct seq_file *m)
+{
+	return m->private;
+}
+
+static struct bpf_map *seq_file_to_map(struct seq_file *m)
+{
+	return file_inode(m->file)->i_private;
+}
+
+static void map_iter_free(struct map_iter *iter)
+{
+	if (iter) {
+		kfree(iter->key);
+		kfree(iter);
+	}
+}
+
+static struct map_iter *map_iter_alloc(struct bpf_map *map)
+{
+	struct map_iter *iter;
+
+	iter = kzalloc(sizeof(*iter), GFP_KERNEL | __GFP_NOWARN);
+	if (!iter)
+		goto error;
+
+	iter->key = kzalloc(map->key_size, GFP_KERNEL | __GFP_NOWARN);
+	if (!iter->key)
+		goto error;
+
+	return iter;
+
+error:
+	map_iter_free(iter);
+	return NULL;
+}
+
+static void *map_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct bpf_map *map = seq_file_to_map(m);
+	void *key = map_iter(m)->key;
+	void *prev_key;
+
+	(*pos)++;
+	if (map_iter(m)->done)
+		return NULL;
+
+	if (unlikely(v == SEQ_START_TOKEN))
+		prev_key = NULL;
+	else
+		prev_key = key;
+
+	rcu_read_lock();
+	if (map->ops->map_get_next_key(map, prev_key, key)) {
+		map_iter(m)->done = true;
+		key = NULL;
+	}
+	rcu_read_unlock();
+	return key;
+}
+
+static void *map_seq_start(struct seq_file *m, loff_t *pos)
+{
+	if (map_iter(m)->done)
+		return NULL;
+
+	return *pos ? map_iter(m)->key : SEQ_START_TOKEN;
+}
+
+static void map_seq_stop(struct seq_file *m, void *v)
+{
+}
+
+static int map_seq_show(struct seq_file *m, void *v)
+{
+	struct bpf_map *map = seq_file_to_map(m);
+	void *key = map_iter(m)->key;
+
+	if (unlikely(v == SEQ_START_TOKEN)) {
+		seq_puts(m, "# WARNING!! The output is for debug purpose only\n");
+		seq_puts(m, "# WARNING!! The output format will change\n");
+	} else {
+		map->ops->map_seq_show_elem(map, key, m);
+	}
+
+	return 0;
+}
+
+static const struct seq_operations bpffs_map_seq_ops = {
+	.start	= map_seq_start,
+	.next	= map_seq_next,
+	.show	= map_seq_show,
+	.stop	= map_seq_stop,
+};
+
+static int bpffs_map_open(struct inode *inode, struct file *file)
+{
+	struct bpf_map *map = inode->i_private;
+	struct map_iter *iter;
+	struct seq_file *m;
+	int err;
+
+	iter = map_iter_alloc(map);
+	if (!iter)
+		return -ENOMEM;
+
+	err = seq_open(file, &bpffs_map_seq_ops);
+	if (err) {
+		map_iter_free(iter);
+		return err;
+	}
+
+	m = file->private_data;
+	m->private = iter;
+
+	return 0;
+}
+
+static int bpffs_map_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *m = file->private_data;
+
+	map_iter_free(map_iter(m));
+
+	return seq_release(inode, file);
+}
+
+/* bpffs_map_fops should only implement the basic
+ * read operation for a BPF map.  The purpose is to
+ * provide a simple user intuitive way to do
+ * "cat bpffs/pathto/a-pinned-map".
+ *
+ * Other operations (e.g. write, lookup...) should be realized by
+ * the userspace tools (e.g. bpftool) through the
+ * BPF_OBJ_GET_INFO_BY_FD and the map's lookup/update
+ * interface.
+ */
+static const struct file_operations bpffs_map_fops = {
+	.open		= bpffs_map_open,
+	.read		= seq_read,
+	.release	= bpffs_map_release,
+};
+
+static int bpffs_obj_open(struct inode *inode, struct file *file)
+{
+	return -EIO;
+}
+
+static const struct file_operations bpffs_obj_fops = {
+	.open		= bpffs_obj_open,
+};
+
+static int bpf_mkobj_ops(struct dentry *dentry, umode_t mode, void *raw,
+			 const struct inode_operations *iops,
+			 const struct file_operations *fops)
+{
+	struct inode *dir = dentry->d_parent->d_inode;
+	struct inode *inode = bpf_get_inode(dir->i_sb, dir, mode);
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+
+	inode->i_op = iops;
+	inode->i_fop = fops;
+	inode->i_private = raw;
+
+	bpf_dentry_finalize(dentry, inode, dir);
+	return 0;
+}
+
+static int bpf_mkprog(struct dentry *dentry, umode_t mode, void *arg)
+{
+	return bpf_mkobj_ops(dentry, mode, arg, &bpf_prog_iops,
+			     &bpffs_obj_fops);
+}
+
+static int bpf_mkmap(struct dentry *dentry, umode_t mode, void *arg)
+{
+	struct bpf_map *map = arg;
+
+	return bpf_mkobj_ops(dentry, mode, arg, &bpf_map_iops,
+			     bpf_map_support_seq_show(map) ?
+			     &bpffs_map_fops : &bpffs_obj_fops);
+}
+
+static int bpf_mklink(struct dentry *dentry, umode_t mode, void *arg)
+{
+	struct bpf_link *link = arg;
+
+	return bpf_mkobj_ops(dentry, mode, arg, &bpf_link_iops,
+			     bpf_link_is_iter(link) ?
+			     &bpf_iter_fops : &bpffs_obj_fops);
+}
+
+static struct dentry *
+bpf_lookup(struct inode *dir, struct dentry *dentry, unsigned flags)
+{
+	/* Dots in names (e.g. "/sys/fs/bpf/foo.bar") are reserved for future
+	 * extensions. That allows popoulate_bpffs() create special files.
+	 */
+	if ((dir->i_mode & S_IALLUGO) &&
+	    strchr(dentry->d_name.name, '.'))
+		return ERR_PTR(-EPERM);
+
+	return simple_lookup(dir, dentry, flags);
+}
+
+static int bpf_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, const char *target)
+{
+	char *link = kstrdup(target, GFP_USER | __GFP_NOWARN);
+	struct inode *inode;
+
+	if (!link)
+		return -ENOMEM;
+
+	inode = bpf_get_inode(dir->i_sb, dir, S_IRWXUGO | S_IFLNK);
+	if (IS_ERR(inode)) {
+		kfree(link);
+		return PTR_ERR(inode);
+	}
+
+	inode->i_op = &simple_symlink_inode_operations;
+	inode->i_link = link;
+
+	bpf_dentry_finalize(dentry, inode, dir);
+	return 0;
+}
+
+static const struct inode_operations bpf_dir_iops = {
+	.lookup		= bpf_lookup,
+	.mkdir		= bpf_mkdir,
+	.symlink	= bpf_symlink,
+	.rmdir		= simple_rmdir,
+	.rename		= simple_rename,
+	.link		= simple_link,
+	.unlink		= simple_unlink,
+};
+
+/* pin iterator link into bpffs */
+static int bpf_iter_link_pin_kernel(struct dentry *parent,
+				    const char *name, struct bpf_link *link)
+{
+	umode_t mode = S_IFREG | S_IRUSR;
+	struct dentry *dentry;
+	int ret;
+
+	inode_lock(parent->d_inode);
+	dentry = lookup_one_len(name, parent, strlen(name));
+	if (IS_ERR(dentry)) {
+		inode_unlock(parent->d_inode);
+		return PTR_ERR(dentry);
+	}
+	ret = bpf_mkobj_ops(dentry, mode, link, &bpf_link_iops,
+			    &bpf_iter_fops);
+	dput(dentry);
+	inode_unlock(parent->d_inode);
+	return ret;
+}
+
+static int bpf_obj_do_pin(const char __user *pathname, void *raw,
+			  enum bpf_type type)
+{
+	struct dentry *dentry;
+	struct inode *dir;
+	struct path path;
+	umode_t mode;
+	int ret;
+
+	dentry = user_path_create(AT_FDCWD, pathname, &path, 0);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+
+	mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask());
+
+	ret = security_path_mknod(&path, dentry, mode, 0);
+	if (ret)
+		goto out;
+
+	dir = d_inode(path.dentry);
+	if (dir->i_op != &bpf_dir_iops) {
+		ret = -EPERM;
+		goto out;
+	}
+
+	switch (type) {
+	case BPF_TYPE_PROG:
+		ret = vfs_mkobj(dentry, mode, bpf_mkprog, raw);
+		break;
+	case BPF_TYPE_MAP:
+		ret = vfs_mkobj(dentry, mode, bpf_mkmap, raw);
+		break;
+	case BPF_TYPE_LINK:
+		ret = vfs_mkobj(dentry, mode, bpf_mklink, raw);
+		break;
+	default:
+		ret = -EPERM;
+	}
+out:
+	done_path_create(&path, dentry);
+	return ret;
+}
+
+int bpf_obj_pin_user(u32 ufd, const char __user *pathname)
+{
+	enum bpf_type type;
+	void *raw;
+	int ret;
+
+	raw = bpf_fd_probe_obj(ufd, &type);
+	if (IS_ERR(raw))
+		return PTR_ERR(raw);
+
+	ret = bpf_obj_do_pin(pathname, raw, type);
+	if (ret != 0)
+		bpf_any_put(raw, type);
+
+	return ret;
+}
+
+static void *bpf_obj_do_get(const char __user *pathname,
+			    enum bpf_type *type, int flags)
+{
+	struct inode *inode;
+	struct path path;
+	void *raw;
+	int ret;
+
+	ret = user_path_at(AT_FDCWD, pathname, LOOKUP_FOLLOW, &path);
+	if (ret)
+		return ERR_PTR(ret);
+
+	inode = d_backing_inode(path.dentry);
+	ret = path_permission(&path, ACC_MODE(flags));
+	if (ret)
+		goto out;
+
+	ret = bpf_inode_type(inode, type);
+	if (ret)
+		goto out;
+
+	raw = bpf_any_get(inode->i_private, *type);
+	if (!IS_ERR(raw))
+		touch_atime(&path);
+
+	path_put(&path);
+	return raw;
+out:
+	path_put(&path);
+	return ERR_PTR(ret);
+}
+
+int bpf_obj_get_user(const char __user *pathname, int flags)
+{
+	enum bpf_type type = BPF_TYPE_UNSPEC;
+	int f_flags;
+	void *raw;
+	int ret;
+
+	f_flags = bpf_get_file_flag(flags);
+	if (f_flags < 0)
+		return f_flags;
+
+	raw = bpf_obj_do_get(pathname, &type, f_flags);
+	if (IS_ERR(raw))
+		return PTR_ERR(raw);
+
+	if (type == BPF_TYPE_PROG)
+		ret = bpf_prog_new_fd(raw);
+	else if (type == BPF_TYPE_MAP)
+		ret = bpf_map_new_fd(raw, f_flags);
+	else if (type == BPF_TYPE_LINK)
+		ret = (f_flags != O_RDWR) ? -EINVAL : bpf_link_new_fd(raw);
+	else
+		return -ENOENT;
+
+	if (ret < 0)
+		bpf_any_put(raw, type);
+	return ret;
+}
+
+static struct bpf_prog *__get_prog_inode(struct inode *inode, enum bpf_prog_type type)
+{
+	struct bpf_prog *prog;
+	int ret = inode_permission(&init_user_ns, inode, MAY_READ);
+	if (ret)
+		return ERR_PTR(ret);
+
+	if (inode->i_op == &bpf_map_iops)
+		return ERR_PTR(-EINVAL);
+	if (inode->i_op == &bpf_link_iops)
+		return ERR_PTR(-EINVAL);
+	if (inode->i_op != &bpf_prog_iops)
+		return ERR_PTR(-EACCES);
+
+	prog = inode->i_private;
+
+	ret = security_bpf_prog(prog);
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	if (!bpf_prog_get_ok(prog, &type, false))
+		return ERR_PTR(-EINVAL);
+
+	bpf_prog_inc(prog);
+	return prog;
+}
+
+struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type type)
+{
+	struct bpf_prog *prog;
+	struct path path;
+	int ret = kern_path(name, LOOKUP_FOLLOW, &path);
+	if (ret)
+		return ERR_PTR(ret);
+	prog = __get_prog_inode(d_backing_inode(path.dentry), type);
+	if (!IS_ERR(prog))
+		touch_atime(&path);
+	path_put(&path);
+	return prog;
+}
+EXPORT_SYMBOL(bpf_prog_get_type_path);
+
+/*
+ * Display the mount options in /proc/mounts.
+ */
+static int bpf_show_options(struct seq_file *m, struct dentry *root)
+{
+	umode_t mode = d_inode(root)->i_mode & S_IALLUGO & ~S_ISVTX;
+
+	if (mode != S_IRWXUGO)
+		seq_printf(m, ",mode=%o", mode);
+	return 0;
+}
+
+static void bpf_free_inode(struct inode *inode)
+{
+	enum bpf_type type;
+
+	if (S_ISLNK(inode->i_mode))
+		kfree(inode->i_link);
+	if (!bpf_inode_type(inode, &type))
+		bpf_any_put(inode->i_private, type);
+	free_inode_nonrcu(inode);
+}
+
+static const struct super_operations bpf_super_ops = {
+	.statfs		= simple_statfs,
+	.drop_inode	= generic_delete_inode,
+	.show_options	= bpf_show_options,
+	.free_inode	= bpf_free_inode,
+};
+
+enum {
+	OPT_MODE,
+};
+
+static const struct fs_parameter_spec bpf_fs_parameters[] = {
+	fsparam_u32oct	("mode",			OPT_MODE),
+	{}
+};
+
+struct bpf_mount_opts {
+	umode_t mode;
+};
+
+static int bpf_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct bpf_mount_opts *opts = fc->fs_private;
+	struct fs_parse_result result;
+	int opt;
+
+	opt = fs_parse(fc, bpf_fs_parameters, param, &result);
+	if (opt < 0) {
+		/* We might like to report bad mount options here, but
+		 * traditionally we've ignored all mount options, so we'd
+		 * better continue to ignore non-existing options for bpf.
+		 */
+		if (opt == -ENOPARAM) {
+			opt = vfs_parse_fs_param_source(fc, param);
+			if (opt != -ENOPARAM)
+				return opt;
+
+			return 0;
+		}
+
+		if (opt < 0)
+			return opt;
+	}
+
+	switch (opt) {
+	case OPT_MODE:
+		opts->mode = result.uint_32 & S_IALLUGO;
+		break;
+	}
+
+	return 0;
+}
+
+struct bpf_preload_ops *bpf_preload_ops;
+EXPORT_SYMBOL_GPL(bpf_preload_ops);
+
+static bool bpf_preload_mod_get(void)
+{
+	/* If bpf_preload.ko wasn't loaded earlier then load it now.
+	 * When bpf_preload is built into vmlinux the module's __init
+	 * function will populate it.
+	 */
+	if (!bpf_preload_ops) {
+		request_module("bpf_preload");
+		if (!bpf_preload_ops)
+			return false;
+	}
+	/* And grab the reference, so the module doesn't disappear while the
+	 * kernel is interacting with the kernel module and its UMD.
+	 */
+	if (!try_module_get(bpf_preload_ops->owner)) {
+		pr_err("bpf_preload module get failed.\n");
+		return false;
+	}
+	return true;
+}
+
+static void bpf_preload_mod_put(void)
+{
+	if (bpf_preload_ops)
+		/* now user can "rmmod bpf_preload" if necessary */
+		module_put(bpf_preload_ops->owner);
+}
+
+static DEFINE_MUTEX(bpf_preload_lock);
+
+static int populate_bpffs(struct dentry *parent)
+{
+	struct bpf_preload_info objs[BPF_PRELOAD_LINKS] = {};
+	int err = 0, i;
+
+	/* grab the mutex to make sure the kernel interactions with bpf_preload
+	 * are serialized
+	 */
+	mutex_lock(&bpf_preload_lock);
+
+	/* if bpf_preload.ko wasn't built into vmlinux then load it */
+	if (!bpf_preload_mod_get())
+		goto out;
+
+	err = bpf_preload_ops->preload(objs);
+	if (err)
+		goto out_put;
+	for (i = 0; i < BPF_PRELOAD_LINKS; i++) {
+		bpf_link_inc(objs[i].link);
+		err = bpf_iter_link_pin_kernel(parent,
+					       objs[i].link_name, objs[i].link);
+		if (err) {
+			bpf_link_put(objs[i].link);
+			goto out_put;
+		}
+	}
+out_put:
+	bpf_preload_mod_put();
+out:
+	mutex_unlock(&bpf_preload_lock);
+	return err;
+}
+
+static int bpf_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+	static const struct tree_descr bpf_rfiles[] = { { "" } };
+	struct bpf_mount_opts *opts = fc->fs_private;
+	struct inode *inode;
+	int ret;
+
+	ret = simple_fill_super(sb, BPF_FS_MAGIC, bpf_rfiles);
+	if (ret)
+		return ret;
+
+	sb->s_op = &bpf_super_ops;
+
+	inode = sb->s_root->d_inode;
+	inode->i_op = &bpf_dir_iops;
+	inode->i_mode &= ~S_IALLUGO;
+	populate_bpffs(sb->s_root);
+	inode->i_mode |= S_ISVTX | opts->mode;
+	return 0;
+}
+
+static int bpf_get_tree(struct fs_context *fc)
+{
+	return get_tree_nodev(fc, bpf_fill_super);
+}
+
+static void bpf_free_fc(struct fs_context *fc)
+{
+	kfree(fc->fs_private);
+}
+
+static const struct fs_context_operations bpf_context_ops = {
+	.free		= bpf_free_fc,
+	.parse_param	= bpf_parse_param,
+	.get_tree	= bpf_get_tree,
+};
+
+/*
+ * Set up the filesystem mount context.
+ */
+static int bpf_init_fs_context(struct fs_context *fc)
+{
+	struct bpf_mount_opts *opts;
+
+	opts = kzalloc(sizeof(struct bpf_mount_opts), GFP_KERNEL);
+	if (!opts)
+		return -ENOMEM;
+
+	opts->mode = S_IRWXUGO;
+
+	fc->fs_private = opts;
+	fc->ops = &bpf_context_ops;
+	return 0;
+}
+
+static struct file_system_type bpf_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "bpf",
+	.init_fs_context = bpf_init_fs_context,
+	.parameters	= bpf_fs_parameters,
+	.kill_sb	= kill_litter_super,
+};
+
+static int __init bpf_init(void)
+{
+	int ret;
+
+	ret = sysfs_create_mount_point(fs_kobj, "bpf");
+	if (ret)
+		return ret;
+
+	ret = register_filesystem(&bpf_fs_type);
+	if (ret)
+		sysfs_remove_mount_point(fs_kobj, "bpf");
+
+	return ret;
+}
+fs_initcall(bpf_init);
diff --git a/kernel/bpf/link_iter.c b/kernel/bpf/link_iter.c
new file mode 100644
index 000000000..fec8005a1
--- /dev/null
+++ b/kernel/bpf/link_iter.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2022 Red Hat, Inc. */
+#include <linux/bpf.h>
+#include <linux/fs.h>
+#include <linux/filter.h>
+#include <linux/kernel.h>
+#include <linux/btf_ids.h>
+
+struct bpf_iter_seq_link_info {
+	u32 link_id;
+};
+
+static void *bpf_link_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct bpf_iter_seq_link_info *info = seq->private;
+	struct bpf_link *link;
+
+	link = bpf_link_get_curr_or_next(&info->link_id);
+	if (!link)
+		return NULL;
+
+	if (*pos == 0)
+		++*pos;
+	return link;
+}
+
+static void *bpf_link_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct bpf_iter_seq_link_info *info = seq->private;
+
+	++*pos;
+	++info->link_id;
+	bpf_link_put((struct bpf_link *)v);
+	return bpf_link_get_curr_or_next(&info->link_id);
+}
+
+struct bpf_iter__bpf_link {
+	__bpf_md_ptr(struct bpf_iter_meta *, meta);
+	__bpf_md_ptr(struct bpf_link *, link);
+};
+
+DEFINE_BPF_ITER_FUNC(bpf_link, struct bpf_iter_meta *meta, struct bpf_link *link)
+
+static int __bpf_link_seq_show(struct seq_file *seq, void *v, bool in_stop)
+{
+	struct bpf_iter__bpf_link ctx;
+	struct bpf_iter_meta meta;
+	struct bpf_prog *prog;
+	int ret = 0;
+
+	ctx.meta = &meta;
+	ctx.link = v;
+	meta.seq = seq;
+	prog = bpf_iter_get_info(&meta, in_stop);
+	if (prog)
+		ret = bpf_iter_run_prog(prog, &ctx);
+
+	return ret;
+}
+
+static int bpf_link_seq_show(struct seq_file *seq, void *v)
+{
+	return __bpf_link_seq_show(seq, v, false);
+}
+
+static void bpf_link_seq_stop(struct seq_file *seq, void *v)
+{
+	if (!v)
+		(void)__bpf_link_seq_show(seq, v, true);
+	else
+		bpf_link_put((struct bpf_link *)v);
+}
+
+static const struct seq_operations bpf_link_seq_ops = {
+	.start	= bpf_link_seq_start,
+	.next	= bpf_link_seq_next,
+	.stop	= bpf_link_seq_stop,
+	.show	= bpf_link_seq_show,
+};
+
+BTF_ID_LIST(btf_bpf_link_id)
+BTF_ID(struct, bpf_link)
+
+static const struct bpf_iter_seq_info bpf_link_seq_info = {
+	.seq_ops		= &bpf_link_seq_ops,
+	.init_seq_private	= NULL,
+	.fini_seq_private	= NULL,
+	.seq_priv_size		= sizeof(struct bpf_iter_seq_link_info),
+};
+
+static struct bpf_iter_reg bpf_link_reg_info = {
+	.target			= "bpf_link",
+	.ctx_arg_info_size	= 1,
+	.ctx_arg_info		= {
+		{ offsetof(struct bpf_iter__bpf_link, link),
+		  PTR_TO_BTF_ID_OR_NULL },
+	},
+	.seq_info		= &bpf_link_seq_info,
+};
+
+static int __init bpf_link_iter_init(void)
+{
+	bpf_link_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_link_id;
+	return bpf_iter_reg_target(&bpf_link_reg_info);
+}
+
+late_initcall(bpf_link_iter_init);
diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c
new file mode 100644
index 000000000..f01ca6f1e
--- /dev/null
+++ b/kernel/bpf/local_storage.c
@@ -0,0 +1,607 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf-cgroup.h>
+#include <linux/bpf.h>
+#include <linux/bpf_local_storage.h>
+#include <linux/btf.h>
+#include <linux/bug.h>
+#include <linux/filter.h>
+#include <linux/mm.h>
+#include <linux/rbtree.h>
+#include <linux/slab.h>
+#include <uapi/linux/btf.h>
+#include <linux/btf_ids.h>
+
+#ifdef CONFIG_CGROUP_BPF
+
+#include "../cgroup/cgroup-internal.h"
+
+#define LOCAL_STORAGE_CREATE_FLAG_MASK					\
+	(BPF_F_NUMA_NODE | BPF_F_ACCESS_MASK)
+
+struct bpf_cgroup_storage_map {
+	struct bpf_map map;
+
+	spinlock_t lock;
+	struct rb_root root;
+	struct list_head list;
+};
+
+static struct bpf_cgroup_storage_map *map_to_storage(struct bpf_map *map)
+{
+	return container_of(map, struct bpf_cgroup_storage_map, map);
+}
+
+static bool attach_type_isolated(const struct bpf_map *map)
+{
+	return map->key_size == sizeof(struct bpf_cgroup_storage_key);
+}
+
+static int bpf_cgroup_storage_key_cmp(const struct bpf_cgroup_storage_map *map,
+				      const void *_key1, const void *_key2)
+{
+	if (attach_type_isolated(&map->map)) {
+		const struct bpf_cgroup_storage_key *key1 = _key1;
+		const struct bpf_cgroup_storage_key *key2 = _key2;
+
+		if (key1->cgroup_inode_id < key2->cgroup_inode_id)
+			return -1;
+		else if (key1->cgroup_inode_id > key2->cgroup_inode_id)
+			return 1;
+		else if (key1->attach_type < key2->attach_type)
+			return -1;
+		else if (key1->attach_type > key2->attach_type)
+			return 1;
+	} else {
+		const __u64 *cgroup_inode_id1 = _key1;
+		const __u64 *cgroup_inode_id2 = _key2;
+
+		if (*cgroup_inode_id1 < *cgroup_inode_id2)
+			return -1;
+		else if (*cgroup_inode_id1 > *cgroup_inode_id2)
+			return 1;
+	}
+	return 0;
+}
+
+struct bpf_cgroup_storage *
+cgroup_storage_lookup(struct bpf_cgroup_storage_map *map,
+		      void *key, bool locked)
+{
+	struct rb_root *root = &map->root;
+	struct rb_node *node;
+
+	if (!locked)
+		spin_lock_bh(&map->lock);
+
+	node = root->rb_node;
+	while (node) {
+		struct bpf_cgroup_storage *storage;
+
+		storage = container_of(node, struct bpf_cgroup_storage, node);
+
+		switch (bpf_cgroup_storage_key_cmp(map, key, &storage->key)) {
+		case -1:
+			node = node->rb_left;
+			break;
+		case 1:
+			node = node->rb_right;
+			break;
+		default:
+			if (!locked)
+				spin_unlock_bh(&map->lock);
+			return storage;
+		}
+	}
+
+	if (!locked)
+		spin_unlock_bh(&map->lock);
+
+	return NULL;
+}
+
+static int cgroup_storage_insert(struct bpf_cgroup_storage_map *map,
+				 struct bpf_cgroup_storage *storage)
+{
+	struct rb_root *root = &map->root;
+	struct rb_node **new = &(root->rb_node), *parent = NULL;
+
+	while (*new) {
+		struct bpf_cgroup_storage *this;
+
+		this = container_of(*new, struct bpf_cgroup_storage, node);
+
+		parent = *new;
+		switch (bpf_cgroup_storage_key_cmp(map, &storage->key, &this->key)) {
+		case -1:
+			new = &((*new)->rb_left);
+			break;
+		case 1:
+			new = &((*new)->rb_right);
+			break;
+		default:
+			return -EEXIST;
+		}
+	}
+
+	rb_link_node(&storage->node, parent, new);
+	rb_insert_color(&storage->node, root);
+
+	return 0;
+}
+
+static void *cgroup_storage_lookup_elem(struct bpf_map *_map, void *key)
+{
+	struct bpf_cgroup_storage_map *map = map_to_storage(_map);
+	struct bpf_cgroup_storage *storage;
+
+	storage = cgroup_storage_lookup(map, key, false);
+	if (!storage)
+		return NULL;
+
+	return &READ_ONCE(storage->buf)->data[0];
+}
+
+static int cgroup_storage_update_elem(struct bpf_map *map, void *key,
+				      void *value, u64 flags)
+{
+	struct bpf_cgroup_storage *storage;
+	struct bpf_storage_buffer *new;
+
+	if (unlikely(flags & ~(BPF_F_LOCK | BPF_EXIST)))
+		return -EINVAL;
+
+	if (unlikely((flags & BPF_F_LOCK) &&
+		     !map_value_has_spin_lock(map)))
+		return -EINVAL;
+
+	storage = cgroup_storage_lookup((struct bpf_cgroup_storage_map *)map,
+					key, false);
+	if (!storage)
+		return -ENOENT;
+
+	if (flags & BPF_F_LOCK) {
+		copy_map_value_locked(map, storage->buf->data, value, false);
+		return 0;
+	}
+
+	new = bpf_map_kmalloc_node(map, struct_size(new, data, map->value_size),
+				   __GFP_ZERO | GFP_NOWAIT | __GFP_NOWARN,
+				   map->numa_node);
+	if (!new)
+		return -ENOMEM;
+
+	memcpy(&new->data[0], value, map->value_size);
+	check_and_init_map_value(map, new->data);
+
+	new = xchg(&storage->buf, new);
+	kfree_rcu(new, rcu);
+
+	return 0;
+}
+
+int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key,
+				   void *value)
+{
+	struct bpf_cgroup_storage_map *map = map_to_storage(_map);
+	struct bpf_cgroup_storage *storage;
+	int cpu, off = 0;
+	u32 size;
+
+	rcu_read_lock();
+	storage = cgroup_storage_lookup(map, key, false);
+	if (!storage) {
+		rcu_read_unlock();
+		return -ENOENT;
+	}
+
+	/* per_cpu areas are zero-filled and bpf programs can only
+	 * access 'value_size' of them, so copying rounded areas
+	 * will not leak any kernel data
+	 */
+	size = round_up(_map->value_size, 8);
+	for_each_possible_cpu(cpu) {
+		bpf_long_memcpy(value + off,
+				per_cpu_ptr(storage->percpu_buf, cpu), size);
+		off += size;
+	}
+	rcu_read_unlock();
+	return 0;
+}
+
+int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key,
+				     void *value, u64 map_flags)
+{
+	struct bpf_cgroup_storage_map *map = map_to_storage(_map);
+	struct bpf_cgroup_storage *storage;
+	int cpu, off = 0;
+	u32 size;
+
+	if (map_flags != BPF_ANY && map_flags != BPF_EXIST)
+		return -EINVAL;
+
+	rcu_read_lock();
+	storage = cgroup_storage_lookup(map, key, false);
+	if (!storage) {
+		rcu_read_unlock();
+		return -ENOENT;
+	}
+
+	/* the user space will provide round_up(value_size, 8) bytes that
+	 * will be copied into per-cpu area. bpf programs can only access
+	 * value_size of it. During lookup the same extra bytes will be
+	 * returned or zeros which were zero-filled by percpu_alloc,
+	 * so no kernel data leaks possible
+	 */
+	size = round_up(_map->value_size, 8);
+	for_each_possible_cpu(cpu) {
+		bpf_long_memcpy(per_cpu_ptr(storage->percpu_buf, cpu),
+				value + off, size);
+		off += size;
+	}
+	rcu_read_unlock();
+	return 0;
+}
+
+static int cgroup_storage_get_next_key(struct bpf_map *_map, void *key,
+				       void *_next_key)
+{
+	struct bpf_cgroup_storage_map *map = map_to_storage(_map);
+	struct bpf_cgroup_storage *storage;
+
+	spin_lock_bh(&map->lock);
+
+	if (list_empty(&map->list))
+		goto enoent;
+
+	if (key) {
+		storage = cgroup_storage_lookup(map, key, true);
+		if (!storage)
+			goto enoent;
+
+		storage = list_next_entry(storage, list_map);
+		if (!storage)
+			goto enoent;
+	} else {
+		storage = list_first_entry(&map->list,
+					 struct bpf_cgroup_storage, list_map);
+	}
+
+	spin_unlock_bh(&map->lock);
+
+	if (attach_type_isolated(&map->map)) {
+		struct bpf_cgroup_storage_key *next = _next_key;
+		*next = storage->key;
+	} else {
+		__u64 *next = _next_key;
+		*next = storage->key.cgroup_inode_id;
+	}
+	return 0;
+
+enoent:
+	spin_unlock_bh(&map->lock);
+	return -ENOENT;
+}
+
+static struct bpf_map *cgroup_storage_map_alloc(union bpf_attr *attr)
+{
+	__u32 max_value_size = BPF_LOCAL_STORAGE_MAX_VALUE_SIZE;
+	int numa_node = bpf_map_attr_numa_node(attr);
+	struct bpf_cgroup_storage_map *map;
+
+	/* percpu is bound by PCPU_MIN_UNIT_SIZE, non-percu
+	 * is the same as other local storages.
+	 */
+	if (attr->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
+		max_value_size = min_t(__u32, max_value_size,
+				       PCPU_MIN_UNIT_SIZE);
+
+	if (attr->key_size != sizeof(struct bpf_cgroup_storage_key) &&
+	    attr->key_size != sizeof(__u64))
+		return ERR_PTR(-EINVAL);
+
+	if (attr->value_size == 0)
+		return ERR_PTR(-EINVAL);
+
+	if (attr->value_size > max_value_size)
+		return ERR_PTR(-E2BIG);
+
+	if (attr->map_flags & ~LOCAL_STORAGE_CREATE_FLAG_MASK ||
+	    !bpf_map_flags_access_ok(attr->map_flags))
+		return ERR_PTR(-EINVAL);
+
+	if (attr->max_entries)
+		/* max_entries is not used and enforced to be 0 */
+		return ERR_PTR(-EINVAL);
+
+	map = bpf_map_area_alloc(sizeof(struct bpf_cgroup_storage_map), numa_node);
+	if (!map)
+		return ERR_PTR(-ENOMEM);
+
+	/* copy mandatory map attributes */
+	bpf_map_init_from_attr(&map->map, attr);
+
+	spin_lock_init(&map->lock);
+	map->root = RB_ROOT;
+	INIT_LIST_HEAD(&map->list);
+
+	return &map->map;
+}
+
+static void cgroup_storage_map_free(struct bpf_map *_map)
+{
+	struct bpf_cgroup_storage_map *map = map_to_storage(_map);
+	struct list_head *storages = &map->list;
+	struct bpf_cgroup_storage *storage, *stmp;
+
+	cgroup_lock();
+
+	list_for_each_entry_safe(storage, stmp, storages, list_map) {
+		bpf_cgroup_storage_unlink(storage);
+		bpf_cgroup_storage_free(storage);
+	}
+
+	cgroup_unlock();
+
+	WARN_ON(!RB_EMPTY_ROOT(&map->root));
+	WARN_ON(!list_empty(&map->list));
+
+	bpf_map_area_free(map);
+}
+
+static int cgroup_storage_delete_elem(struct bpf_map *map, void *key)
+{
+	return -EINVAL;
+}
+
+static int cgroup_storage_check_btf(const struct bpf_map *map,
+				    const struct btf *btf,
+				    const struct btf_type *key_type,
+				    const struct btf_type *value_type)
+{
+	if (attach_type_isolated(map)) {
+		struct btf_member *m;
+		u32 offset, size;
+
+		/* Key is expected to be of struct bpf_cgroup_storage_key type,
+		 * which is:
+		 * struct bpf_cgroup_storage_key {
+		 *	__u64	cgroup_inode_id;
+		 *	__u32	attach_type;
+		 * };
+		 */
+
+		/*
+		 * Key_type must be a structure with two fields.
+		 */
+		if (BTF_INFO_KIND(key_type->info) != BTF_KIND_STRUCT ||
+		    BTF_INFO_VLEN(key_type->info) != 2)
+			return -EINVAL;
+
+		/*
+		 * The first field must be a 64 bit integer at 0 offset.
+		 */
+		m = (struct btf_member *)(key_type + 1);
+		size = sizeof_field(struct bpf_cgroup_storage_key, cgroup_inode_id);
+		if (!btf_member_is_reg_int(btf, key_type, m, 0, size))
+			return -EINVAL;
+
+		/*
+		 * The second field must be a 32 bit integer at 64 bit offset.
+		 */
+		m++;
+		offset = offsetof(struct bpf_cgroup_storage_key, attach_type);
+		size = sizeof_field(struct bpf_cgroup_storage_key, attach_type);
+		if (!btf_member_is_reg_int(btf, key_type, m, offset, size))
+			return -EINVAL;
+	} else {
+		u32 int_data;
+
+		/*
+		 * Key is expected to be u64, which stores the cgroup_inode_id
+		 */
+
+		if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
+			return -EINVAL;
+
+		int_data = *(u32 *)(key_type + 1);
+		if (BTF_INT_BITS(int_data) != 64 || BTF_INT_OFFSET(int_data))
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void cgroup_storage_seq_show_elem(struct bpf_map *map, void *key,
+					 struct seq_file *m)
+{
+	enum bpf_cgroup_storage_type stype;
+	struct bpf_cgroup_storage *storage;
+	int cpu;
+
+	rcu_read_lock();
+	storage = cgroup_storage_lookup(map_to_storage(map), key, false);
+	if (!storage) {
+		rcu_read_unlock();
+		return;
+	}
+
+	btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
+	stype = cgroup_storage_type(map);
+	if (stype == BPF_CGROUP_STORAGE_SHARED) {
+		seq_puts(m, ": ");
+		btf_type_seq_show(map->btf, map->btf_value_type_id,
+				  &READ_ONCE(storage->buf)->data[0], m);
+		seq_puts(m, "\n");
+	} else {
+		seq_puts(m, ": {\n");
+		for_each_possible_cpu(cpu) {
+			seq_printf(m, "\tcpu%d: ", cpu);
+			btf_type_seq_show(map->btf, map->btf_value_type_id,
+					  per_cpu_ptr(storage->percpu_buf, cpu),
+					  m);
+			seq_puts(m, "\n");
+		}
+		seq_puts(m, "}\n");
+	}
+	rcu_read_unlock();
+}
+
+BTF_ID_LIST_SINGLE(cgroup_storage_map_btf_ids, struct,
+		   bpf_cgroup_storage_map)
+const struct bpf_map_ops cgroup_storage_map_ops = {
+	.map_alloc = cgroup_storage_map_alloc,
+	.map_free = cgroup_storage_map_free,
+	.map_get_next_key = cgroup_storage_get_next_key,
+	.map_lookup_elem = cgroup_storage_lookup_elem,
+	.map_update_elem = cgroup_storage_update_elem,
+	.map_delete_elem = cgroup_storage_delete_elem,
+	.map_check_btf = cgroup_storage_check_btf,
+	.map_seq_show_elem = cgroup_storage_seq_show_elem,
+	.map_btf_id = &cgroup_storage_map_btf_ids[0],
+};
+
+int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *_map)
+{
+	enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map);
+
+	if (aux->cgroup_storage[stype] &&
+	    aux->cgroup_storage[stype] != _map)
+		return -EBUSY;
+
+	aux->cgroup_storage[stype] = _map;
+	return 0;
+}
+
+static size_t bpf_cgroup_storage_calculate_size(struct bpf_map *map, u32 *pages)
+{
+	size_t size;
+
+	if (cgroup_storage_type(map) == BPF_CGROUP_STORAGE_SHARED) {
+		size = sizeof(struct bpf_storage_buffer) + map->value_size;
+		*pages = round_up(sizeof(struct bpf_cgroup_storage) + size,
+				  PAGE_SIZE) >> PAGE_SHIFT;
+	} else {
+		size = map->value_size;
+		*pages = round_up(round_up(size, 8) * num_possible_cpus(),
+				  PAGE_SIZE) >> PAGE_SHIFT;
+	}
+
+	return size;
+}
+
+struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog,
+					enum bpf_cgroup_storage_type stype)
+{
+	const gfp_t gfp = __GFP_ZERO | GFP_USER;
+	struct bpf_cgroup_storage *storage;
+	struct bpf_map *map;
+	size_t size;
+	u32 pages;
+
+	map = prog->aux->cgroup_storage[stype];
+	if (!map)
+		return NULL;
+
+	size = bpf_cgroup_storage_calculate_size(map, &pages);
+
+	storage = bpf_map_kmalloc_node(map, sizeof(struct bpf_cgroup_storage),
+				       gfp, map->numa_node);
+	if (!storage)
+		goto enomem;
+
+	if (stype == BPF_CGROUP_STORAGE_SHARED) {
+		storage->buf = bpf_map_kmalloc_node(map, size, gfp,
+						    map->numa_node);
+		if (!storage->buf)
+			goto enomem;
+		check_and_init_map_value(map, storage->buf->data);
+	} else {
+		storage->percpu_buf = bpf_map_alloc_percpu(map, size, 8, gfp);
+		if (!storage->percpu_buf)
+			goto enomem;
+	}
+
+	storage->map = (struct bpf_cgroup_storage_map *)map;
+
+	return storage;
+
+enomem:
+	kfree(storage);
+	return ERR_PTR(-ENOMEM);
+}
+
+static void free_shared_cgroup_storage_rcu(struct rcu_head *rcu)
+{
+	struct bpf_cgroup_storage *storage =
+		container_of(rcu, struct bpf_cgroup_storage, rcu);
+
+	kfree(storage->buf);
+	kfree(storage);
+}
+
+static void free_percpu_cgroup_storage_rcu(struct rcu_head *rcu)
+{
+	struct bpf_cgroup_storage *storage =
+		container_of(rcu, struct bpf_cgroup_storage, rcu);
+
+	free_percpu(storage->percpu_buf);
+	kfree(storage);
+}
+
+void bpf_cgroup_storage_free(struct bpf_cgroup_storage *storage)
+{
+	enum bpf_cgroup_storage_type stype;
+	struct bpf_map *map;
+
+	if (!storage)
+		return;
+
+	map = &storage->map->map;
+	stype = cgroup_storage_type(map);
+	if (stype == BPF_CGROUP_STORAGE_SHARED)
+		call_rcu(&storage->rcu, free_shared_cgroup_storage_rcu);
+	else
+		call_rcu(&storage->rcu, free_percpu_cgroup_storage_rcu);
+}
+
+void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage,
+			     struct cgroup *cgroup,
+			     enum bpf_attach_type type)
+{
+	struct bpf_cgroup_storage_map *map;
+
+	if (!storage)
+		return;
+
+	storage->key.attach_type = type;
+	storage->key.cgroup_inode_id = cgroup_id(cgroup);
+
+	map = storage->map;
+
+	spin_lock_bh(&map->lock);
+	WARN_ON(cgroup_storage_insert(map, storage));
+	list_add(&storage->list_map, &map->list);
+	list_add(&storage->list_cg, &cgroup->bpf.storages);
+	spin_unlock_bh(&map->lock);
+}
+
+void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage)
+{
+	struct bpf_cgroup_storage_map *map;
+	struct rb_root *root;
+
+	if (!storage)
+		return;
+
+	map = storage->map;
+
+	spin_lock_bh(&map->lock);
+	root = &map->root;
+	rb_erase(&storage->node, root);
+
+	list_del(&storage->list_map);
+	list_del(&storage->list_cg);
+	spin_unlock_bh(&map->lock);
+}
+
+#endif
diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
new file mode 100644
index 000000000..ce3a091d5
--- /dev/null
+++ b/kernel/bpf/lpm_trie.c
@@ -0,0 +1,740 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Longest prefix match list implementation
+ *
+ * Copyright (c) 2016,2017 Daniel Mack
+ * Copyright (c) 2016 David Herrmann
+ */
+
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
+#include <net/ipv6.h>
+#include <uapi/linux/btf.h>
+#include <linux/btf_ids.h>
+
+/* Intermediate node */
+#define LPM_TREE_NODE_FLAG_IM BIT(0)
+
+struct lpm_trie_node;
+
+struct lpm_trie_node {
+	struct rcu_head rcu;
+	struct lpm_trie_node __rcu	*child[2];
+	u32				prefixlen;
+	u32				flags;
+	u8				data[];
+};
+
+struct lpm_trie {
+	struct bpf_map			map;
+	struct lpm_trie_node __rcu	*root;
+	size_t				n_entries;
+	size_t				max_prefixlen;
+	size_t				data_size;
+	spinlock_t			lock;
+};
+
+/* This trie implements a longest prefix match algorithm that can be used to
+ * match IP addresses to a stored set of ranges.
+ *
+ * Data stored in @data of struct bpf_lpm_key and struct lpm_trie_node is
+ * interpreted as big endian, so data[0] stores the most significant byte.
+ *
+ * Match ranges are internally stored in instances of struct lpm_trie_node
+ * which each contain their prefix length as well as two pointers that may
+ * lead to more nodes containing more specific matches. Each node also stores
+ * a value that is defined by and returned to userspace via the update_elem
+ * and lookup functions.
+ *
+ * For instance, let's start with a trie that was created with a prefix length
+ * of 32, so it can be used for IPv4 addresses, and one single element that
+ * matches 192.168.0.0/16. The data array would hence contain
+ * [0xc0, 0xa8, 0x00, 0x00] in big-endian notation. This documentation will
+ * stick to IP-address notation for readability though.
+ *
+ * As the trie is empty initially, the new node (1) will be places as root
+ * node, denoted as (R) in the example below. As there are no other node, both
+ * child pointers are %NULL.
+ *
+ *              +----------------+
+ *              |       (1)  (R) |
+ *              | 192.168.0.0/16 |
+ *              |    value: 1    |
+ *              |   [0]    [1]   |
+ *              +----------------+
+ *
+ * Next, let's add a new node (2) matching 192.168.0.0/24. As there is already
+ * a node with the same data and a smaller prefix (ie, a less specific one),
+ * node (2) will become a child of (1). In child index depends on the next bit
+ * that is outside of what (1) matches, and that bit is 0, so (2) will be
+ * child[0] of (1):
+ *
+ *              +----------------+
+ *              |       (1)  (R) |
+ *              | 192.168.0.0/16 |
+ *              |    value: 1    |
+ *              |   [0]    [1]   |
+ *              +----------------+
+ *                   |
+ *    +----------------+
+ *    |       (2)      |
+ *    | 192.168.0.0/24 |
+ *    |    value: 2    |
+ *    |   [0]    [1]   |
+ *    +----------------+
+ *
+ * The child[1] slot of (1) could be filled with another node which has bit #17
+ * (the next bit after the ones that (1) matches on) set to 1. For instance,
+ * 192.168.128.0/24:
+ *
+ *              +----------------+
+ *              |       (1)  (R) |
+ *              | 192.168.0.0/16 |
+ *              |    value: 1    |
+ *              |   [0]    [1]   |
+ *              +----------------+
+ *                   |      |
+ *    +----------------+  +------------------+
+ *    |       (2)      |  |        (3)       |
+ *    | 192.168.0.0/24 |  | 192.168.128.0/24 |
+ *    |    value: 2    |  |     value: 3     |
+ *    |   [0]    [1]   |  |    [0]    [1]    |
+ *    +----------------+  +------------------+
+ *
+ * Let's add another node (4) to the game for 192.168.1.0/24. In order to place
+ * it, node (1) is looked at first, and because (4) of the semantics laid out
+ * above (bit #17 is 0), it would normally be attached to (1) as child[0].
+ * However, that slot is already allocated, so a new node is needed in between.
+ * That node does not have a value attached to it and it will never be
+ * returned to users as result of a lookup. It is only there to differentiate
+ * the traversal further. It will get a prefix as wide as necessary to
+ * distinguish its two children:
+ *
+ *                      +----------------+
+ *                      |       (1)  (R) |
+ *                      | 192.168.0.0/16 |
+ *                      |    value: 1    |
+ *                      |   [0]    [1]   |
+ *                      +----------------+
+ *                           |      |
+ *            +----------------+  +------------------+
+ *            |       (4)  (I) |  |        (3)       |
+ *            | 192.168.0.0/23 |  | 192.168.128.0/24 |
+ *            |    value: ---  |  |     value: 3     |
+ *            |   [0]    [1]   |  |    [0]    [1]    |
+ *            +----------------+  +------------------+
+ *                 |      |
+ *  +----------------+  +----------------+
+ *  |       (2)      |  |       (5)      |
+ *  | 192.168.0.0/24 |  | 192.168.1.0/24 |
+ *  |    value: 2    |  |     value: 5   |
+ *  |   [0]    [1]   |  |   [0]    [1]   |
+ *  +----------------+  +----------------+
+ *
+ * 192.168.1.1/32 would be a child of (5) etc.
+ *
+ * An intermediate node will be turned into a 'real' node on demand. In the
+ * example above, (4) would be re-used if 192.168.0.0/23 is added to the trie.
+ *
+ * A fully populated trie would have a height of 32 nodes, as the trie was
+ * created with a prefix length of 32.
+ *
+ * The lookup starts at the root node. If the current node matches and if there
+ * is a child that can be used to become more specific, the trie is traversed
+ * downwards. The last node in the traversal that is a non-intermediate one is
+ * returned.
+ */
+
+static inline int extract_bit(const u8 *data, size_t index)
+{
+	return !!(data[index / 8] & (1 << (7 - (index % 8))));
+}
+
+/**
+ * longest_prefix_match() - determine the longest prefix
+ * @trie:	The trie to get internal sizes from
+ * @node:	The node to operate on
+ * @key:	The key to compare to @node
+ *
+ * Determine the longest prefix of @node that matches the bits in @key.
+ */
+static size_t longest_prefix_match(const struct lpm_trie *trie,
+				   const struct lpm_trie_node *node,
+				   const struct bpf_lpm_trie_key *key)
+{
+	u32 limit = min(node->prefixlen, key->prefixlen);
+	u32 prefixlen = 0, i = 0;
+
+	BUILD_BUG_ON(offsetof(struct lpm_trie_node, data) % sizeof(u32));
+	BUILD_BUG_ON(offsetof(struct bpf_lpm_trie_key, data) % sizeof(u32));
+
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(CONFIG_64BIT)
+
+	/* data_size >= 16 has very small probability.
+	 * We do not use a loop for optimal code generation.
+	 */
+	if (trie->data_size >= 8) {
+		u64 diff = be64_to_cpu(*(__be64 *)node->data ^
+				       *(__be64 *)key->data);
+
+		prefixlen = 64 - fls64(diff);
+		if (prefixlen >= limit)
+			return limit;
+		if (diff)
+			return prefixlen;
+		i = 8;
+	}
+#endif
+
+	while (trie->data_size >= i + 4) {
+		u32 diff = be32_to_cpu(*(__be32 *)&node->data[i] ^
+				       *(__be32 *)&key->data[i]);
+
+		prefixlen += 32 - fls(diff);
+		if (prefixlen >= limit)
+			return limit;
+		if (diff)
+			return prefixlen;
+		i += 4;
+	}
+
+	if (trie->data_size >= i + 2) {
+		u16 diff = be16_to_cpu(*(__be16 *)&node->data[i] ^
+				       *(__be16 *)&key->data[i]);
+
+		prefixlen += 16 - fls(diff);
+		if (prefixlen >= limit)
+			return limit;
+		if (diff)
+			return prefixlen;
+		i += 2;
+	}
+
+	if (trie->data_size >= i + 1) {
+		prefixlen += 8 - fls(node->data[i] ^ key->data[i]);
+
+		if (prefixlen >= limit)
+			return limit;
+	}
+
+	return prefixlen;
+}
+
+/* Called from syscall or from eBPF program */
+static void *trie_lookup_elem(struct bpf_map *map, void *_key)
+{
+	struct lpm_trie *trie = container_of(map, struct lpm_trie, map);
+	struct lpm_trie_node *node, *found = NULL;
+	struct bpf_lpm_trie_key *key = _key;
+
+	if (key->prefixlen > trie->max_prefixlen)
+		return NULL;
+
+	/* Start walking the trie from the root node ... */
+
+	for (node = rcu_dereference_check(trie->root, rcu_read_lock_bh_held());
+	     node;) {
+		unsigned int next_bit;
+		size_t matchlen;
+
+		/* Determine the longest prefix of @node that matches @key.
+		 * If it's the maximum possible prefix for this trie, we have
+		 * an exact match and can return it directly.
+		 */
+		matchlen = longest_prefix_match(trie, node, key);
+		if (matchlen == trie->max_prefixlen) {
+			found = node;
+			break;
+		}
+
+		/* If the number of bits that match is smaller than the prefix
+		 * length of @node, bail out and return the node we have seen
+		 * last in the traversal (ie, the parent).
+		 */
+		if (matchlen < node->prefixlen)
+			break;
+
+		/* Consider this node as return candidate unless it is an
+		 * artificially added intermediate one.
+		 */
+		if (!(node->flags & LPM_TREE_NODE_FLAG_IM))
+			found = node;
+
+		/* If the node match is fully satisfied, let's see if we can
+		 * become more specific. Determine the next bit in the key and
+		 * traverse down.
+		 */
+		next_bit = extract_bit(key->data, node->prefixlen);
+		node = rcu_dereference_check(node->child[next_bit],
+					     rcu_read_lock_bh_held());
+	}
+
+	if (!found)
+		return NULL;
+
+	return found->data + trie->data_size;
+}
+
+static struct lpm_trie_node *lpm_trie_node_alloc(const struct lpm_trie *trie,
+						 const void *value)
+{
+	struct lpm_trie_node *node;
+	size_t size = sizeof(struct lpm_trie_node) + trie->data_size;
+
+	if (value)
+		size += trie->map.value_size;
+
+	node = bpf_map_kmalloc_node(&trie->map, size, GFP_NOWAIT | __GFP_NOWARN,
+				    trie->map.numa_node);
+	if (!node)
+		return NULL;
+
+	node->flags = 0;
+
+	if (value)
+		memcpy(node->data + trie->data_size, value,
+		       trie->map.value_size);
+
+	return node;
+}
+
+/* Called from syscall or from eBPF program */
+static int trie_update_elem(struct bpf_map *map,
+			    void *_key, void *value, u64 flags)
+{
+	struct lpm_trie *trie = container_of(map, struct lpm_trie, map);
+	struct lpm_trie_node *node, *im_node = NULL, *new_node = NULL;
+	struct lpm_trie_node __rcu **slot;
+	struct bpf_lpm_trie_key *key = _key;
+	unsigned long irq_flags;
+	unsigned int next_bit;
+	size_t matchlen = 0;
+	int ret = 0;
+
+	if (unlikely(flags > BPF_EXIST))
+		return -EINVAL;
+
+	if (key->prefixlen > trie->max_prefixlen)
+		return -EINVAL;
+
+	spin_lock_irqsave(&trie->lock, irq_flags);
+
+	/* Allocate and fill a new node */
+
+	if (trie->n_entries == trie->map.max_entries) {
+		ret = -ENOSPC;
+		goto out;
+	}
+
+	new_node = lpm_trie_node_alloc(trie, value);
+	if (!new_node) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	trie->n_entries++;
+
+	new_node->prefixlen = key->prefixlen;
+	RCU_INIT_POINTER(new_node->child[0], NULL);
+	RCU_INIT_POINTER(new_node->child[1], NULL);
+	memcpy(new_node->data, key->data, trie->data_size);
+
+	/* Now find a slot to attach the new node. To do that, walk the tree
+	 * from the root and match as many bits as possible for each node until
+	 * we either find an empty slot or a slot that needs to be replaced by
+	 * an intermediate node.
+	 */
+	slot = &trie->root;
+
+	while ((node = rcu_dereference_protected(*slot,
+					lockdep_is_held(&trie->lock)))) {
+		matchlen = longest_prefix_match(trie, node, key);
+
+		if (node->prefixlen != matchlen ||
+		    node->prefixlen == key->prefixlen ||
+		    node->prefixlen == trie->max_prefixlen)
+			break;
+
+		next_bit = extract_bit(key->data, node->prefixlen);
+		slot = &node->child[next_bit];
+	}
+
+	/* If the slot is empty (a free child pointer or an empty root),
+	 * simply assign the @new_node to that slot and be done.
+	 */
+	if (!node) {
+		rcu_assign_pointer(*slot, new_node);
+		goto out;
+	}
+
+	/* If the slot we picked already exists, replace it with @new_node
+	 * which already has the correct data array set.
+	 */
+	if (node->prefixlen == matchlen) {
+		new_node->child[0] = node->child[0];
+		new_node->child[1] = node->child[1];
+
+		if (!(node->flags & LPM_TREE_NODE_FLAG_IM))
+			trie->n_entries--;
+
+		rcu_assign_pointer(*slot, new_node);
+		kfree_rcu(node, rcu);
+
+		goto out;
+	}
+
+	/* If the new node matches the prefix completely, it must be inserted
+	 * as an ancestor. Simply insert it between @node and *@slot.
+	 */
+	if (matchlen == key->prefixlen) {
+		next_bit = extract_bit(node->data, matchlen);
+		rcu_assign_pointer(new_node->child[next_bit], node);
+		rcu_assign_pointer(*slot, new_node);
+		goto out;
+	}
+
+	im_node = lpm_trie_node_alloc(trie, NULL);
+	if (!im_node) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	im_node->prefixlen = matchlen;
+	im_node->flags |= LPM_TREE_NODE_FLAG_IM;
+	memcpy(im_node->data, node->data, trie->data_size);
+
+	/* Now determine which child to install in which slot */
+	if (extract_bit(key->data, matchlen)) {
+		rcu_assign_pointer(im_node->child[0], node);
+		rcu_assign_pointer(im_node->child[1], new_node);
+	} else {
+		rcu_assign_pointer(im_node->child[0], new_node);
+		rcu_assign_pointer(im_node->child[1], node);
+	}
+
+	/* Finally, assign the intermediate node to the determined slot */
+	rcu_assign_pointer(*slot, im_node);
+
+out:
+	if (ret) {
+		if (new_node)
+			trie->n_entries--;
+
+		kfree(new_node);
+		kfree(im_node);
+	}
+
+	spin_unlock_irqrestore(&trie->lock, irq_flags);
+
+	return ret;
+}
+
+/* Called from syscall or from eBPF program */
+static int trie_delete_elem(struct bpf_map *map, void *_key)
+{
+	struct lpm_trie *trie = container_of(map, struct lpm_trie, map);
+	struct bpf_lpm_trie_key *key = _key;
+	struct lpm_trie_node __rcu **trim, **trim2;
+	struct lpm_trie_node *node, *parent;
+	unsigned long irq_flags;
+	unsigned int next_bit;
+	size_t matchlen = 0;
+	int ret = 0;
+
+	if (key->prefixlen > trie->max_prefixlen)
+		return -EINVAL;
+
+	spin_lock_irqsave(&trie->lock, irq_flags);
+
+	/* Walk the tree looking for an exact key/length match and keeping
+	 * track of the path we traverse.  We will need to know the node
+	 * we wish to delete, and the slot that points to the node we want
+	 * to delete.  We may also need to know the nodes parent and the
+	 * slot that contains it.
+	 */
+	trim = &trie->root;
+	trim2 = trim;
+	parent = NULL;
+	while ((node = rcu_dereference_protected(
+		       *trim, lockdep_is_held(&trie->lock)))) {
+		matchlen = longest_prefix_match(trie, node, key);
+
+		if (node->prefixlen != matchlen ||
+		    node->prefixlen == key->prefixlen)
+			break;
+
+		parent = node;
+		trim2 = trim;
+		next_bit = extract_bit(key->data, node->prefixlen);
+		trim = &node->child[next_bit];
+	}
+
+	if (!node || node->prefixlen != key->prefixlen ||
+	    node->prefixlen != matchlen ||
+	    (node->flags & LPM_TREE_NODE_FLAG_IM)) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	trie->n_entries--;
+
+	/* If the node we are removing has two children, simply mark it
+	 * as intermediate and we are done.
+	 */
+	if (rcu_access_pointer(node->child[0]) &&
+	    rcu_access_pointer(node->child[1])) {
+		node->flags |= LPM_TREE_NODE_FLAG_IM;
+		goto out;
+	}
+
+	/* If the parent of the node we are about to delete is an intermediate
+	 * node, and the deleted node doesn't have any children, we can delete
+	 * the intermediate parent as well and promote its other child
+	 * up the tree.  Doing this maintains the invariant that all
+	 * intermediate nodes have exactly 2 children and that there are no
+	 * unnecessary intermediate nodes in the tree.
+	 */
+	if (parent && (parent->flags & LPM_TREE_NODE_FLAG_IM) &&
+	    !node->child[0] && !node->child[1]) {
+		if (node == rcu_access_pointer(parent->child[0]))
+			rcu_assign_pointer(
+				*trim2, rcu_access_pointer(parent->child[1]));
+		else
+			rcu_assign_pointer(
+				*trim2, rcu_access_pointer(parent->child[0]));
+		kfree_rcu(parent, rcu);
+		kfree_rcu(node, rcu);
+		goto out;
+	}
+
+	/* The node we are removing has either zero or one child. If there
+	 * is a child, move it into the removed node's slot then delete
+	 * the node.  Otherwise just clear the slot and delete the node.
+	 */
+	if (node->child[0])
+		rcu_assign_pointer(*trim, rcu_access_pointer(node->child[0]));
+	else if (node->child[1])
+		rcu_assign_pointer(*trim, rcu_access_pointer(node->child[1]));
+	else
+		RCU_INIT_POINTER(*trim, NULL);
+	kfree_rcu(node, rcu);
+
+out:
+	spin_unlock_irqrestore(&trie->lock, irq_flags);
+
+	return ret;
+}
+
+#define LPM_DATA_SIZE_MAX	256
+#define LPM_DATA_SIZE_MIN	1
+
+#define LPM_VAL_SIZE_MAX	(KMALLOC_MAX_SIZE - LPM_DATA_SIZE_MAX - \
+				 sizeof(struct lpm_trie_node))
+#define LPM_VAL_SIZE_MIN	1
+
+#define LPM_KEY_SIZE(X)		(sizeof(struct bpf_lpm_trie_key) + (X))
+#define LPM_KEY_SIZE_MAX	LPM_KEY_SIZE(LPM_DATA_SIZE_MAX)
+#define LPM_KEY_SIZE_MIN	LPM_KEY_SIZE(LPM_DATA_SIZE_MIN)
+
+#define LPM_CREATE_FLAG_MASK	(BPF_F_NO_PREALLOC | BPF_F_NUMA_NODE |	\
+				 BPF_F_ACCESS_MASK)
+
+static struct bpf_map *trie_alloc(union bpf_attr *attr)
+{
+	struct lpm_trie *trie;
+
+	if (!bpf_capable())
+		return ERR_PTR(-EPERM);
+
+	/* check sanity of attributes */
+	if (attr->max_entries == 0 ||
+	    !(attr->map_flags & BPF_F_NO_PREALLOC) ||
+	    attr->map_flags & ~LPM_CREATE_FLAG_MASK ||
+	    !bpf_map_flags_access_ok(attr->map_flags) ||
+	    attr->key_size < LPM_KEY_SIZE_MIN ||
+	    attr->key_size > LPM_KEY_SIZE_MAX ||
+	    attr->value_size < LPM_VAL_SIZE_MIN ||
+	    attr->value_size > LPM_VAL_SIZE_MAX)
+		return ERR_PTR(-EINVAL);
+
+	trie = bpf_map_area_alloc(sizeof(*trie), NUMA_NO_NODE);
+	if (!trie)
+		return ERR_PTR(-ENOMEM);
+
+	/* copy mandatory map attributes */
+	bpf_map_init_from_attr(&trie->map, attr);
+	trie->data_size = attr->key_size -
+			  offsetof(struct bpf_lpm_trie_key, data);
+	trie->max_prefixlen = trie->data_size * 8;
+
+	spin_lock_init(&trie->lock);
+
+	return &trie->map;
+}
+
+static void trie_free(struct bpf_map *map)
+{
+	struct lpm_trie *trie = container_of(map, struct lpm_trie, map);
+	struct lpm_trie_node __rcu **slot;
+	struct lpm_trie_node *node;
+
+	/* Always start at the root and walk down to a node that has no
+	 * children. Then free that node, nullify its reference in the parent
+	 * and start over.
+	 */
+
+	for (;;) {
+		slot = &trie->root;
+
+		for (;;) {
+			node = rcu_dereference_protected(*slot, 1);
+			if (!node)
+				goto out;
+
+			if (rcu_access_pointer(node->child[0])) {
+				slot = &node->child[0];
+				continue;
+			}
+
+			if (rcu_access_pointer(node->child[1])) {
+				slot = &node->child[1];
+				continue;
+			}
+
+			kfree(node);
+			RCU_INIT_POINTER(*slot, NULL);
+			break;
+		}
+	}
+
+out:
+	bpf_map_area_free(trie);
+}
+
+static int trie_get_next_key(struct bpf_map *map, void *_key, void *_next_key)
+{
+	struct lpm_trie_node *node, *next_node = NULL, *parent, *search_root;
+	struct lpm_trie *trie = container_of(map, struct lpm_trie, map);
+	struct bpf_lpm_trie_key *key = _key, *next_key = _next_key;
+	struct lpm_trie_node **node_stack = NULL;
+	int err = 0, stack_ptr = -1;
+	unsigned int next_bit;
+	size_t matchlen;
+
+	/* The get_next_key follows postorder. For the 4 node example in
+	 * the top of this file, the trie_get_next_key() returns the following
+	 * one after another:
+	 *   192.168.0.0/24
+	 *   192.168.1.0/24
+	 *   192.168.128.0/24
+	 *   192.168.0.0/16
+	 *
+	 * The idea is to return more specific keys before less specific ones.
+	 */
+
+	/* Empty trie */
+	search_root = rcu_dereference(trie->root);
+	if (!search_root)
+		return -ENOENT;
+
+	/* For invalid key, find the leftmost node in the trie */
+	if (!key || key->prefixlen > trie->max_prefixlen)
+		goto find_leftmost;
+
+	node_stack = kmalloc_array(trie->max_prefixlen,
+				   sizeof(struct lpm_trie_node *),
+				   GFP_ATOMIC | __GFP_NOWARN);
+	if (!node_stack)
+		return -ENOMEM;
+
+	/* Try to find the exact node for the given key */
+	for (node = search_root; node;) {
+		node_stack[++stack_ptr] = node;
+		matchlen = longest_prefix_match(trie, node, key);
+		if (node->prefixlen != matchlen ||
+		    node->prefixlen == key->prefixlen)
+			break;
+
+		next_bit = extract_bit(key->data, node->prefixlen);
+		node = rcu_dereference(node->child[next_bit]);
+	}
+	if (!node || node->prefixlen != key->prefixlen ||
+	    (node->flags & LPM_TREE_NODE_FLAG_IM))
+		goto find_leftmost;
+
+	/* The node with the exactly-matching key has been found,
+	 * find the first node in postorder after the matched node.
+	 */
+	node = node_stack[stack_ptr];
+	while (stack_ptr > 0) {
+		parent = node_stack[stack_ptr - 1];
+		if (rcu_dereference(parent->child[0]) == node) {
+			search_root = rcu_dereference(parent->child[1]);
+			if (search_root)
+				goto find_leftmost;
+		}
+		if (!(parent->flags & LPM_TREE_NODE_FLAG_IM)) {
+			next_node = parent;
+			goto do_copy;
+		}
+
+		node = parent;
+		stack_ptr--;
+	}
+
+	/* did not find anything */
+	err = -ENOENT;
+	goto free_stack;
+
+find_leftmost:
+	/* Find the leftmost non-intermediate node, all intermediate nodes
+	 * have exact two children, so this function will never return NULL.
+	 */
+	for (node = search_root; node;) {
+		if (node->flags & LPM_TREE_NODE_FLAG_IM) {
+			node = rcu_dereference(node->child[0]);
+		} else {
+			next_node = node;
+			node = rcu_dereference(node->child[0]);
+			if (!node)
+				node = rcu_dereference(next_node->child[1]);
+		}
+	}
+do_copy:
+	next_key->prefixlen = next_node->prefixlen;
+	memcpy((void *)next_key + offsetof(struct bpf_lpm_trie_key, data),
+	       next_node->data, trie->data_size);
+free_stack:
+	kfree(node_stack);
+	return err;
+}
+
+static int trie_check_btf(const struct bpf_map *map,
+			  const struct btf *btf,
+			  const struct btf_type *key_type,
+			  const struct btf_type *value_type)
+{
+	/* Keys must have struct bpf_lpm_trie_key embedded. */
+	return BTF_INFO_KIND(key_type->info) != BTF_KIND_STRUCT ?
+	       -EINVAL : 0;
+}
+
+BTF_ID_LIST_SINGLE(trie_map_btf_ids, struct, lpm_trie)
+const struct bpf_map_ops trie_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc = trie_alloc,
+	.map_free = trie_free,
+	.map_get_next_key = trie_get_next_key,
+	.map_lookup_elem = trie_lookup_elem,
+	.map_update_elem = trie_update_elem,
+	.map_delete_elem = trie_delete_elem,
+	.map_lookup_batch = generic_map_lookup_batch,
+	.map_update_batch = generic_map_update_batch,
+	.map_delete_batch = generic_map_delete_batch,
+	.map_check_btf = trie_check_btf,
+	.map_btf_id = &trie_map_btf_ids[0],
+};
diff --git a/kernel/bpf/map_in_map.c b/kernel/bpf/map_in_map.c
new file mode 100644
index 000000000..141f33320
--- /dev/null
+++ b/kernel/bpf/map_in_map.c
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2017 Facebook
+ */
+#include <linux/slab.h>
+#include <linux/bpf.h>
+#include <linux/btf.h>
+
+#include "map_in_map.h"
+
+struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd)
+{
+	struct bpf_map *inner_map, *inner_map_meta;
+	u32 inner_map_meta_size;
+	struct fd f;
+
+	f = fdget(inner_map_ufd);
+	inner_map = __bpf_map_get(f);
+	if (IS_ERR(inner_map))
+		return inner_map;
+
+	/* Does not support >1 level map-in-map */
+	if (inner_map->inner_map_meta) {
+		fdput(f);
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (!inner_map->ops->map_meta_equal) {
+		fdput(f);
+		return ERR_PTR(-ENOTSUPP);
+	}
+
+	if (map_value_has_spin_lock(inner_map)) {
+		fdput(f);
+		return ERR_PTR(-ENOTSUPP);
+	}
+
+	inner_map_meta_size = sizeof(*inner_map_meta);
+	/* In some cases verifier needs to access beyond just base map. */
+	if (inner_map->ops == &array_map_ops)
+		inner_map_meta_size = sizeof(struct bpf_array);
+
+	inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER);
+	if (!inner_map_meta) {
+		fdput(f);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	inner_map_meta->map_type = inner_map->map_type;
+	inner_map_meta->key_size = inner_map->key_size;
+	inner_map_meta->value_size = inner_map->value_size;
+	inner_map_meta->map_flags = inner_map->map_flags;
+	inner_map_meta->max_entries = inner_map->max_entries;
+	inner_map_meta->spin_lock_off = inner_map->spin_lock_off;
+	inner_map_meta->timer_off = inner_map->timer_off;
+	inner_map_meta->kptr_off_tab = bpf_map_copy_kptr_off_tab(inner_map);
+	if (inner_map->btf) {
+		btf_get(inner_map->btf);
+		inner_map_meta->btf = inner_map->btf;
+	}
+
+	/* Misc members not needed in bpf_map_meta_equal() check. */
+	inner_map_meta->ops = inner_map->ops;
+	if (inner_map->ops == &array_map_ops) {
+		struct bpf_array *inner_array_meta =
+			container_of(inner_map_meta, struct bpf_array, map);
+		struct bpf_array *inner_array = container_of(inner_map, struct bpf_array, map);
+
+		inner_array_meta->index_mask = inner_array->index_mask;
+		inner_array_meta->elem_size = inner_array->elem_size;
+		inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1;
+	}
+
+	fdput(f);
+	return inner_map_meta;
+}
+
+void bpf_map_meta_free(struct bpf_map *map_meta)
+{
+	bpf_map_free_kptr_off_tab(map_meta);
+	btf_put(map_meta->btf);
+	kfree(map_meta);
+}
+
+bool bpf_map_meta_equal(const struct bpf_map *meta0,
+			const struct bpf_map *meta1)
+{
+	/* No need to compare ops because it is covered by map_type */
+	return meta0->map_type == meta1->map_type &&
+		meta0->key_size == meta1->key_size &&
+		meta0->value_size == meta1->value_size &&
+		meta0->timer_off == meta1->timer_off &&
+		meta0->map_flags == meta1->map_flags &&
+		bpf_map_equal_kptr_off_tab(meta0, meta1);
+}
+
+void *bpf_map_fd_get_ptr(struct bpf_map *map,
+			 struct file *map_file /* not used */,
+			 int ufd)
+{
+	struct bpf_map *inner_map, *inner_map_meta;
+	struct fd f;
+
+	f = fdget(ufd);
+	inner_map = __bpf_map_get(f);
+	if (IS_ERR(inner_map))
+		return inner_map;
+
+	inner_map_meta = map->inner_map_meta;
+	if (inner_map_meta->ops->map_meta_equal(inner_map_meta, inner_map))
+		bpf_map_inc(inner_map);
+	else
+		inner_map = ERR_PTR(-EINVAL);
+
+	fdput(f);
+	return inner_map;
+}
+
+void bpf_map_fd_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
+{
+	struct bpf_map *inner_map = ptr;
+
+	/* The inner map may still be used by both non-sleepable and sleepable
+	 * bpf program, so free it after one RCU grace period and one tasks
+	 * trace RCU grace period.
+	 */
+	if (need_defer)
+		WRITE_ONCE(inner_map->free_after_mult_rcu_gp, true);
+	bpf_map_put(inner_map);
+}
+
+u32 bpf_map_fd_sys_lookup_elem(void *ptr)
+{
+	return ((struct bpf_map *)ptr)->id;
+}
diff --git a/kernel/bpf/map_in_map.h b/kernel/bpf/map_in_map.h
new file mode 100644
index 000000000..7d6160235
--- /dev/null
+++ b/kernel/bpf/map_in_map.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (c) 2017 Facebook
+ */
+#ifndef __MAP_IN_MAP_H__
+#define __MAP_IN_MAP_H__
+
+#include <linux/types.h>
+
+struct file;
+struct bpf_map;
+
+struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd);
+void bpf_map_meta_free(struct bpf_map *map_meta);
+void *bpf_map_fd_get_ptr(struct bpf_map *map, struct file *map_file,
+			 int ufd);
+void bpf_map_fd_put_ptr(struct bpf_map *map, void *ptr, bool need_defer);
+u32 bpf_map_fd_sys_lookup_elem(void *ptr);
+
+#endif
diff --git a/kernel/bpf/map_iter.c b/kernel/bpf/map_iter.c
new file mode 100644
index 000000000..b0fa190b0
--- /dev/null
+++ b/kernel/bpf/map_iter.c
@@ -0,0 +1,195 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2020 Facebook */
+#include <linux/bpf.h>
+#include <linux/fs.h>
+#include <linux/filter.h>
+#include <linux/kernel.h>
+#include <linux/btf_ids.h>
+
+struct bpf_iter_seq_map_info {
+	u32 map_id;
+};
+
+static void *bpf_map_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct bpf_iter_seq_map_info *info = seq->private;
+	struct bpf_map *map;
+
+	map = bpf_map_get_curr_or_next(&info->map_id);
+	if (!map)
+		return NULL;
+
+	if (*pos == 0)
+		++*pos;
+	return map;
+}
+
+static void *bpf_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct bpf_iter_seq_map_info *info = seq->private;
+
+	++*pos;
+	++info->map_id;
+	bpf_map_put((struct bpf_map *)v);
+	return bpf_map_get_curr_or_next(&info->map_id);
+}
+
+struct bpf_iter__bpf_map {
+	__bpf_md_ptr(struct bpf_iter_meta *, meta);
+	__bpf_md_ptr(struct bpf_map *, map);
+};
+
+DEFINE_BPF_ITER_FUNC(bpf_map, struct bpf_iter_meta *meta, struct bpf_map *map)
+
+static int __bpf_map_seq_show(struct seq_file *seq, void *v, bool in_stop)
+{
+	struct bpf_iter__bpf_map ctx;
+	struct bpf_iter_meta meta;
+	struct bpf_prog *prog;
+	int ret = 0;
+
+	ctx.meta = &meta;
+	ctx.map = v;
+	meta.seq = seq;
+	prog = bpf_iter_get_info(&meta, in_stop);
+	if (prog)
+		ret = bpf_iter_run_prog(prog, &ctx);
+
+	return ret;
+}
+
+static int bpf_map_seq_show(struct seq_file *seq, void *v)
+{
+	return __bpf_map_seq_show(seq, v, false);
+}
+
+static void bpf_map_seq_stop(struct seq_file *seq, void *v)
+{
+	if (!v)
+		(void)__bpf_map_seq_show(seq, v, true);
+	else
+		bpf_map_put((struct bpf_map *)v);
+}
+
+static const struct seq_operations bpf_map_seq_ops = {
+	.start	= bpf_map_seq_start,
+	.next	= bpf_map_seq_next,
+	.stop	= bpf_map_seq_stop,
+	.show	= bpf_map_seq_show,
+};
+
+BTF_ID_LIST(btf_bpf_map_id)
+BTF_ID(struct, bpf_map)
+
+static const struct bpf_iter_seq_info bpf_map_seq_info = {
+	.seq_ops		= &bpf_map_seq_ops,
+	.init_seq_private	= NULL,
+	.fini_seq_private	= NULL,
+	.seq_priv_size		= sizeof(struct bpf_iter_seq_map_info),
+};
+
+static struct bpf_iter_reg bpf_map_reg_info = {
+	.target			= "bpf_map",
+	.ctx_arg_info_size	= 1,
+	.ctx_arg_info		= {
+		{ offsetof(struct bpf_iter__bpf_map, map),
+		  PTR_TO_BTF_ID_OR_NULL },
+	},
+	.seq_info		= &bpf_map_seq_info,
+};
+
+static int bpf_iter_attach_map(struct bpf_prog *prog,
+			       union bpf_iter_link_info *linfo,
+			       struct bpf_iter_aux_info *aux)
+{
+	u32 key_acc_size, value_acc_size, key_size, value_size;
+	struct bpf_map *map;
+	bool is_percpu = false;
+	int err = -EINVAL;
+
+	if (!linfo->map.map_fd)
+		return -EBADF;
+
+	map = bpf_map_get_with_uref(linfo->map.map_fd);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+
+	if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+	    map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
+	    map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
+		is_percpu = true;
+	else if (map->map_type != BPF_MAP_TYPE_HASH &&
+		 map->map_type != BPF_MAP_TYPE_LRU_HASH &&
+		 map->map_type != BPF_MAP_TYPE_ARRAY)
+		goto put_map;
+
+	key_acc_size = prog->aux->max_rdonly_access;
+	value_acc_size = prog->aux->max_rdwr_access;
+	key_size = map->key_size;
+	if (!is_percpu)
+		value_size = map->value_size;
+	else
+		value_size = round_up(map->value_size, 8) * num_possible_cpus();
+
+	if (key_acc_size > key_size || value_acc_size > value_size) {
+		err = -EACCES;
+		goto put_map;
+	}
+
+	aux->map = map;
+	return 0;
+
+put_map:
+	bpf_map_put_with_uref(map);
+	return err;
+}
+
+static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux)
+{
+	bpf_map_put_with_uref(aux->map);
+}
+
+void bpf_iter_map_show_fdinfo(const struct bpf_iter_aux_info *aux,
+			      struct seq_file *seq)
+{
+	seq_printf(seq, "map_id:\t%u\n", aux->map->id);
+}
+
+int bpf_iter_map_fill_link_info(const struct bpf_iter_aux_info *aux,
+				struct bpf_link_info *info)
+{
+	info->iter.map.map_id = aux->map->id;
+	return 0;
+}
+
+DEFINE_BPF_ITER_FUNC(bpf_map_elem, struct bpf_iter_meta *meta,
+		     struct bpf_map *map, void *key, void *value)
+
+static const struct bpf_iter_reg bpf_map_elem_reg_info = {
+	.target			= "bpf_map_elem",
+	.attach_target		= bpf_iter_attach_map,
+	.detach_target		= bpf_iter_detach_map,
+	.show_fdinfo		= bpf_iter_map_show_fdinfo,
+	.fill_link_info		= bpf_iter_map_fill_link_info,
+	.ctx_arg_info_size	= 2,
+	.ctx_arg_info		= {
+		{ offsetof(struct bpf_iter__bpf_map_elem, key),
+		  PTR_TO_BUF | PTR_MAYBE_NULL | MEM_RDONLY },
+		{ offsetof(struct bpf_iter__bpf_map_elem, value),
+		  PTR_TO_BUF | PTR_MAYBE_NULL },
+	},
+};
+
+static int __init bpf_map_iter_init(void)
+{
+	int ret;
+
+	bpf_map_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_map_id;
+	ret = bpf_iter_reg_target(&bpf_map_reg_info);
+	if (ret)
+		return ret;
+
+	return bpf_iter_reg_target(&bpf_map_elem_reg_info);
+}
+
+late_initcall(bpf_map_iter_init);
diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c
new file mode 100644
index 000000000..ace303a22
--- /dev/null
+++ b/kernel/bpf/memalloc.c
@@ -0,0 +1,649 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+#include <linux/mm.h>
+#include <linux/llist.h>
+#include <linux/bpf.h>
+#include <linux/irq_work.h>
+#include <linux/bpf_mem_alloc.h>
+#include <linux/memcontrol.h>
+#include <asm/local.h>
+
+/* Any context (including NMI) BPF specific memory allocator.
+ *
+ * Tracing BPF programs can attach to kprobe and fentry. Hence they
+ * run in unknown context where calling plain kmalloc() might not be safe.
+ *
+ * Front-end kmalloc() with per-cpu per-bucket cache of free elements.
+ * Refill this cache asynchronously from irq_work.
+ *
+ * CPU_0 buckets
+ * 16 32 64 96 128 196 256 512 1024 2048 4096
+ * ...
+ * CPU_N buckets
+ * 16 32 64 96 128 196 256 512 1024 2048 4096
+ *
+ * The buckets are prefilled at the start.
+ * BPF programs always run with migration disabled.
+ * It's safe to allocate from cache of the current cpu with irqs disabled.
+ * Free-ing is always done into bucket of the current cpu as well.
+ * irq_work trims extra free elements from buckets with kfree
+ * and refills them with kmalloc, so global kmalloc logic takes care
+ * of freeing objects allocated by one cpu and freed on another.
+ *
+ * Every allocated objected is padded with extra 8 bytes that contains
+ * struct llist_node.
+ */
+#define LLIST_NODE_SZ sizeof(struct llist_node)
+
+/* similar to kmalloc, but sizeof == 8 bucket is gone */
+static u8 size_index[24] __ro_after_init = {
+	3,	/* 8 */
+	3,	/* 16 */
+	4,	/* 24 */
+	4,	/* 32 */
+	5,	/* 40 */
+	5,	/* 48 */
+	5,	/* 56 */
+	5,	/* 64 */
+	1,	/* 72 */
+	1,	/* 80 */
+	1,	/* 88 */
+	1,	/* 96 */
+	6,	/* 104 */
+	6,	/* 112 */
+	6,	/* 120 */
+	6,	/* 128 */
+	2,	/* 136 */
+	2,	/* 144 */
+	2,	/* 152 */
+	2,	/* 160 */
+	2,	/* 168 */
+	2,	/* 176 */
+	2,	/* 184 */
+	2	/* 192 */
+};
+
+static int bpf_mem_cache_idx(size_t size)
+{
+	if (!size || size > 4096)
+		return -1;
+
+	if (size <= 192)
+		return size_index[(size - 1) / 8] - 1;
+
+	return fls(size - 1) - 2;
+}
+
+#define NUM_CACHES 11
+
+struct bpf_mem_cache {
+	/* per-cpu list of free objects of size 'unit_size'.
+	 * All accesses are done with interrupts disabled and 'active' counter
+	 * protection with __llist_add() and __llist_del_first().
+	 */
+	struct llist_head free_llist;
+	local_t active;
+
+	/* Operations on the free_list from unit_alloc/unit_free/bpf_mem_refill
+	 * are sequenced by per-cpu 'active' counter. But unit_free() cannot
+	 * fail. When 'active' is busy the unit_free() will add an object to
+	 * free_llist_extra.
+	 */
+	struct llist_head free_llist_extra;
+
+	struct irq_work refill_work;
+	struct obj_cgroup *objcg;
+	int unit_size;
+	/* count of objects in free_llist */
+	int free_cnt;
+	int low_watermark, high_watermark, batch;
+	int percpu_size;
+
+	struct rcu_head rcu;
+	struct llist_head free_by_rcu;
+	struct llist_head waiting_for_gp;
+	atomic_t call_rcu_in_progress;
+};
+
+struct bpf_mem_caches {
+	struct bpf_mem_cache cache[NUM_CACHES];
+};
+
+static struct llist_node notrace *__llist_del_first(struct llist_head *head)
+{
+	struct llist_node *entry, *next;
+
+	entry = head->first;
+	if (!entry)
+		return NULL;
+	next = entry->next;
+	head->first = next;
+	return entry;
+}
+
+static void *__alloc(struct bpf_mem_cache *c, int node)
+{
+	/* Allocate, but don't deplete atomic reserves that typical
+	 * GFP_ATOMIC would do. irq_work runs on this cpu and kmalloc
+	 * will allocate from the current numa node which is what we
+	 * want here.
+	 */
+	gfp_t flags = GFP_NOWAIT | __GFP_NOWARN | __GFP_ACCOUNT;
+
+	if (c->percpu_size) {
+		void **obj = kmalloc_node(c->percpu_size, flags, node);
+		void *pptr = __alloc_percpu_gfp(c->unit_size, 8, flags);
+
+		if (!obj || !pptr) {
+			free_percpu(pptr);
+			kfree(obj);
+			return NULL;
+		}
+		obj[1] = pptr;
+		return obj;
+	}
+
+	return kmalloc_node(c->unit_size, flags | __GFP_ZERO, node);
+}
+
+static struct mem_cgroup *get_memcg(const struct bpf_mem_cache *c)
+{
+#ifdef CONFIG_MEMCG_KMEM
+	if (c->objcg)
+		return get_mem_cgroup_from_objcg(c->objcg);
+#endif
+
+#ifdef CONFIG_MEMCG
+	return root_mem_cgroup;
+#else
+	return NULL;
+#endif
+}
+
+/* Mostly runs from irq_work except __init phase. */
+static void alloc_bulk(struct bpf_mem_cache *c, int cnt, int node)
+{
+	struct mem_cgroup *memcg = NULL, *old_memcg;
+	unsigned long flags;
+	void *obj;
+	int i;
+
+	memcg = get_memcg(c);
+	old_memcg = set_active_memcg(memcg);
+	for (i = 0; i < cnt; i++) {
+		obj = __alloc(c, node);
+		if (!obj)
+			break;
+		if (IS_ENABLED(CONFIG_PREEMPT_RT))
+			/* In RT irq_work runs in per-cpu kthread, so disable
+			 * interrupts to avoid preemption and interrupts and
+			 * reduce the chance of bpf prog executing on this cpu
+			 * when active counter is busy.
+			 */
+			local_irq_save(flags);
+		/* alloc_bulk runs from irq_work which will not preempt a bpf
+		 * program that does unit_alloc/unit_free since IRQs are
+		 * disabled there. There is no race to increment 'active'
+		 * counter. It protects free_llist from corruption in case NMI
+		 * bpf prog preempted this loop.
+		 */
+		WARN_ON_ONCE(local_inc_return(&c->active) != 1);
+		__llist_add(obj, &c->free_llist);
+		c->free_cnt++;
+		local_dec(&c->active);
+		if (IS_ENABLED(CONFIG_PREEMPT_RT))
+			local_irq_restore(flags);
+	}
+	set_active_memcg(old_memcg);
+	mem_cgroup_put(memcg);
+}
+
+static void free_one(struct bpf_mem_cache *c, void *obj)
+{
+	if (c->percpu_size) {
+		free_percpu(((void **)obj)[1]);
+		kfree(obj);
+		return;
+	}
+
+	kfree(obj);
+}
+
+static void __free_rcu(struct rcu_head *head)
+{
+	struct bpf_mem_cache *c = container_of(head, struct bpf_mem_cache, rcu);
+	struct llist_node *llnode = llist_del_all(&c->waiting_for_gp);
+	struct llist_node *pos, *t;
+
+	llist_for_each_safe(pos, t, llnode)
+		free_one(c, pos);
+	atomic_set(&c->call_rcu_in_progress, 0);
+}
+
+static void __free_rcu_tasks_trace(struct rcu_head *head)
+{
+	struct bpf_mem_cache *c = container_of(head, struct bpf_mem_cache, rcu);
+
+	call_rcu(&c->rcu, __free_rcu);
+}
+
+static void enque_to_free(struct bpf_mem_cache *c, void *obj)
+{
+	struct llist_node *llnode = obj;
+
+	/* bpf_mem_cache is a per-cpu object. Freeing happens in irq_work.
+	 * Nothing races to add to free_by_rcu list.
+	 */
+	__llist_add(llnode, &c->free_by_rcu);
+}
+
+static void do_call_rcu(struct bpf_mem_cache *c)
+{
+	struct llist_node *llnode, *t;
+
+	if (atomic_xchg(&c->call_rcu_in_progress, 1))
+		return;
+
+	WARN_ON_ONCE(!llist_empty(&c->waiting_for_gp));
+	llist_for_each_safe(llnode, t, __llist_del_all(&c->free_by_rcu))
+		/* There is no concurrent __llist_add(waiting_for_gp) access.
+		 * It doesn't race with llist_del_all either.
+		 * But there could be two concurrent llist_del_all(waiting_for_gp):
+		 * from __free_rcu() and from drain_mem_cache().
+		 */
+		__llist_add(llnode, &c->waiting_for_gp);
+	/* Use call_rcu_tasks_trace() to wait for sleepable progs to finish.
+	 * Then use call_rcu() to wait for normal progs to finish
+	 * and finally do free_one() on each element.
+	 */
+	call_rcu_tasks_trace(&c->rcu, __free_rcu_tasks_trace);
+}
+
+static void free_bulk(struct bpf_mem_cache *c)
+{
+	struct llist_node *llnode, *t;
+	unsigned long flags;
+	int cnt;
+
+	do {
+		if (IS_ENABLED(CONFIG_PREEMPT_RT))
+			local_irq_save(flags);
+		WARN_ON_ONCE(local_inc_return(&c->active) != 1);
+		llnode = __llist_del_first(&c->free_llist);
+		if (llnode)
+			cnt = --c->free_cnt;
+		else
+			cnt = 0;
+		local_dec(&c->active);
+		if (IS_ENABLED(CONFIG_PREEMPT_RT))
+			local_irq_restore(flags);
+		if (llnode)
+			enque_to_free(c, llnode);
+	} while (cnt > (c->high_watermark + c->low_watermark) / 2);
+
+	/* and drain free_llist_extra */
+	llist_for_each_safe(llnode, t, llist_del_all(&c->free_llist_extra))
+		enque_to_free(c, llnode);
+	do_call_rcu(c);
+}
+
+static void bpf_mem_refill(struct irq_work *work)
+{
+	struct bpf_mem_cache *c = container_of(work, struct bpf_mem_cache, refill_work);
+	int cnt;
+
+	/* Racy access to free_cnt. It doesn't need to be 100% accurate */
+	cnt = c->free_cnt;
+	if (cnt < c->low_watermark)
+		/* irq_work runs on this cpu and kmalloc will allocate
+		 * from the current numa node which is what we want here.
+		 */
+		alloc_bulk(c, c->batch, NUMA_NO_NODE);
+	else if (cnt > c->high_watermark)
+		free_bulk(c);
+}
+
+static void notrace irq_work_raise(struct bpf_mem_cache *c)
+{
+	irq_work_queue(&c->refill_work);
+}
+
+/* For typical bpf map case that uses bpf_mem_cache_alloc and single bucket
+ * the freelist cache will be elem_size * 64 (or less) on each cpu.
+ *
+ * For bpf programs that don't have statically known allocation sizes and
+ * assuming (low_mark + high_mark) / 2 as an average number of elements per
+ * bucket and all buckets are used the total amount of memory in freelists
+ * on each cpu will be:
+ * 64*16 + 64*32 + 64*64 + 64*96 + 64*128 + 64*196 + 64*256 + 32*512 + 16*1024 + 8*2048 + 4*4096
+ * == ~ 116 Kbyte using below heuristic.
+ * Initialized, but unused bpf allocator (not bpf map specific one) will
+ * consume ~ 11 Kbyte per cpu.
+ * Typical case will be between 11K and 116K closer to 11K.
+ * bpf progs can and should share bpf_mem_cache when possible.
+ */
+
+static void prefill_mem_cache(struct bpf_mem_cache *c, int cpu)
+{
+	init_irq_work(&c->refill_work, bpf_mem_refill);
+	if (c->unit_size <= 256) {
+		c->low_watermark = 32;
+		c->high_watermark = 96;
+	} else {
+		/* When page_size == 4k, order-0 cache will have low_mark == 2
+		 * and high_mark == 6 with batch alloc of 3 individual pages at
+		 * a time.
+		 * 8k allocs and above low == 1, high == 3, batch == 1.
+		 */
+		c->low_watermark = max(32 * 256 / c->unit_size, 1);
+		c->high_watermark = max(96 * 256 / c->unit_size, 3);
+	}
+	c->batch = max((c->high_watermark - c->low_watermark) / 4 * 3, 1);
+
+	/* To avoid consuming memory assume that 1st run of bpf
+	 * prog won't be doing more than 4 map_update_elem from
+	 * irq disabled region
+	 */
+	alloc_bulk(c, c->unit_size <= 256 ? 4 : 1, cpu_to_node(cpu));
+}
+
+/* When size != 0 bpf_mem_cache for each cpu.
+ * This is typical bpf hash map use case when all elements have equal size.
+ *
+ * When size == 0 allocate 11 bpf_mem_cache-s for each cpu, then rely on
+ * kmalloc/kfree. Max allocation size is 4096 in this case.
+ * This is bpf_dynptr and bpf_kptr use case.
+ */
+int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu)
+{
+	static u16 sizes[NUM_CACHES] = {96, 192, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096};
+	struct bpf_mem_caches *cc, __percpu *pcc;
+	struct bpf_mem_cache *c, __percpu *pc;
+	struct obj_cgroup *objcg = NULL;
+	int cpu, i, unit_size, percpu_size = 0;
+
+	if (size) {
+		pc = __alloc_percpu_gfp(sizeof(*pc), 8, GFP_KERNEL);
+		if (!pc)
+			return -ENOMEM;
+
+		if (percpu)
+			/* room for llist_node and per-cpu pointer */
+			percpu_size = LLIST_NODE_SZ + sizeof(void *);
+		else
+			size += LLIST_NODE_SZ; /* room for llist_node */
+		unit_size = size;
+
+#ifdef CONFIG_MEMCG_KMEM
+		objcg = get_obj_cgroup_from_current();
+#endif
+		for_each_possible_cpu(cpu) {
+			c = per_cpu_ptr(pc, cpu);
+			c->unit_size = unit_size;
+			c->objcg = objcg;
+			c->percpu_size = percpu_size;
+			prefill_mem_cache(c, cpu);
+		}
+		ma->cache = pc;
+		return 0;
+	}
+
+	/* size == 0 && percpu is an invalid combination */
+	if (WARN_ON_ONCE(percpu))
+		return -EINVAL;
+
+	pcc = __alloc_percpu_gfp(sizeof(*cc), 8, GFP_KERNEL);
+	if (!pcc)
+		return -ENOMEM;
+#ifdef CONFIG_MEMCG_KMEM
+	objcg = get_obj_cgroup_from_current();
+#endif
+	for_each_possible_cpu(cpu) {
+		cc = per_cpu_ptr(pcc, cpu);
+		for (i = 0; i < NUM_CACHES; i++) {
+			c = &cc->cache[i];
+			c->unit_size = sizes[i];
+			c->objcg = objcg;
+			prefill_mem_cache(c, cpu);
+		}
+	}
+	ma->caches = pcc;
+	return 0;
+}
+
+static void drain_mem_cache(struct bpf_mem_cache *c)
+{
+	struct llist_node *llnode, *t;
+
+	/* No progs are using this bpf_mem_cache, but htab_map_free() called
+	 * bpf_mem_cache_free() for all remaining elements and they can be in
+	 * free_by_rcu or in waiting_for_gp lists, so drain those lists now.
+	 *
+	 * Except for waiting_for_gp list, there are no concurrent operations
+	 * on these lists, so it is safe to use __llist_del_all().
+	 */
+	llist_for_each_safe(llnode, t, __llist_del_all(&c->free_by_rcu))
+		free_one(c, llnode);
+	llist_for_each_safe(llnode, t, llist_del_all(&c->waiting_for_gp))
+		free_one(c, llnode);
+	llist_for_each_safe(llnode, t, __llist_del_all(&c->free_llist))
+		free_one(c, llnode);
+	llist_for_each_safe(llnode, t, __llist_del_all(&c->free_llist_extra))
+		free_one(c, llnode);
+}
+
+static void free_mem_alloc_no_barrier(struct bpf_mem_alloc *ma)
+{
+	free_percpu(ma->cache);
+	free_percpu(ma->caches);
+	ma->cache = NULL;
+	ma->caches = NULL;
+}
+
+static void free_mem_alloc(struct bpf_mem_alloc *ma)
+{
+	/* waiting_for_gp lists was drained, but __free_rcu might
+	 * still execute. Wait for it now before we freeing percpu caches.
+	 */
+	rcu_barrier_tasks_trace();
+	rcu_barrier();
+	free_mem_alloc_no_barrier(ma);
+}
+
+static void free_mem_alloc_deferred(struct work_struct *work)
+{
+	struct bpf_mem_alloc *ma = container_of(work, struct bpf_mem_alloc, work);
+
+	free_mem_alloc(ma);
+	kfree(ma);
+}
+
+static void destroy_mem_alloc(struct bpf_mem_alloc *ma, int rcu_in_progress)
+{
+	struct bpf_mem_alloc *copy;
+
+	if (!rcu_in_progress) {
+		/* Fast path. No callbacks are pending, hence no need to do
+		 * rcu_barrier-s.
+		 */
+		free_mem_alloc_no_barrier(ma);
+		return;
+	}
+
+	copy = kmalloc(sizeof(*ma), GFP_KERNEL);
+	if (!copy) {
+		/* Slow path with inline barrier-s */
+		free_mem_alloc(ma);
+		return;
+	}
+
+	/* Defer barriers into worker to let the rest of map memory to be freed */
+	copy->cache = ma->cache;
+	ma->cache = NULL;
+	copy->caches = ma->caches;
+	ma->caches = NULL;
+	INIT_WORK(&copy->work, free_mem_alloc_deferred);
+	queue_work(system_unbound_wq, &copy->work);
+}
+
+void bpf_mem_alloc_destroy(struct bpf_mem_alloc *ma)
+{
+	struct bpf_mem_caches *cc;
+	struct bpf_mem_cache *c;
+	int cpu, i, rcu_in_progress;
+
+	if (ma->cache) {
+		rcu_in_progress = 0;
+		for_each_possible_cpu(cpu) {
+			c = per_cpu_ptr(ma->cache, cpu);
+			/*
+			 * refill_work may be unfinished for PREEMPT_RT kernel
+			 * in which irq work is invoked in a per-CPU RT thread.
+			 * It is also possible for kernel with
+			 * arch_irq_work_has_interrupt() being false and irq
+			 * work is invoked in timer interrupt. So waiting for
+			 * the completion of irq work to ease the handling of
+			 * concurrency.
+			 */
+			irq_work_sync(&c->refill_work);
+			drain_mem_cache(c);
+			rcu_in_progress += atomic_read(&c->call_rcu_in_progress);
+		}
+		/* objcg is the same across cpus */
+		if (c->objcg)
+			obj_cgroup_put(c->objcg);
+		destroy_mem_alloc(ma, rcu_in_progress);
+	}
+	if (ma->caches) {
+		rcu_in_progress = 0;
+		for_each_possible_cpu(cpu) {
+			cc = per_cpu_ptr(ma->caches, cpu);
+			for (i = 0; i < NUM_CACHES; i++) {
+				c = &cc->cache[i];
+				irq_work_sync(&c->refill_work);
+				drain_mem_cache(c);
+				rcu_in_progress += atomic_read(&c->call_rcu_in_progress);
+			}
+		}
+		if (c->objcg)
+			obj_cgroup_put(c->objcg);
+		destroy_mem_alloc(ma, rcu_in_progress);
+	}
+}
+
+/* notrace is necessary here and in other functions to make sure
+ * bpf programs cannot attach to them and cause llist corruptions.
+ */
+static void notrace *unit_alloc(struct bpf_mem_cache *c)
+{
+	struct llist_node *llnode = NULL;
+	unsigned long flags;
+	int cnt = 0;
+
+	/* Disable irqs to prevent the following race for majority of prog types:
+	 * prog_A
+	 *   bpf_mem_alloc
+	 *      preemption or irq -> prog_B
+	 *        bpf_mem_alloc
+	 *
+	 * but prog_B could be a perf_event NMI prog.
+	 * Use per-cpu 'active' counter to order free_list access between
+	 * unit_alloc/unit_free/bpf_mem_refill.
+	 */
+	local_irq_save(flags);
+	if (local_inc_return(&c->active) == 1) {
+		llnode = __llist_del_first(&c->free_llist);
+		if (llnode)
+			cnt = --c->free_cnt;
+	}
+	local_dec(&c->active);
+	local_irq_restore(flags);
+
+	WARN_ON(cnt < 0);
+
+	if (cnt < c->low_watermark)
+		irq_work_raise(c);
+	return llnode;
+}
+
+/* Though 'ptr' object could have been allocated on a different cpu
+ * add it to the free_llist of the current cpu.
+ * Let kfree() logic deal with it when it's later called from irq_work.
+ */
+static void notrace unit_free(struct bpf_mem_cache *c, void *ptr)
+{
+	struct llist_node *llnode = ptr - LLIST_NODE_SZ;
+	unsigned long flags;
+	int cnt = 0;
+
+	BUILD_BUG_ON(LLIST_NODE_SZ > 8);
+
+	local_irq_save(flags);
+	if (local_inc_return(&c->active) == 1) {
+		__llist_add(llnode, &c->free_llist);
+		cnt = ++c->free_cnt;
+	} else {
+		/* unit_free() cannot fail. Therefore add an object to atomic
+		 * llist. free_bulk() will drain it. Though free_llist_extra is
+		 * a per-cpu list we have to use atomic llist_add here, since
+		 * it also can be interrupted by bpf nmi prog that does another
+		 * unit_free() into the same free_llist_extra.
+		 */
+		llist_add(llnode, &c->free_llist_extra);
+	}
+	local_dec(&c->active);
+	local_irq_restore(flags);
+
+	if (cnt > c->high_watermark)
+		/* free few objects from current cpu into global kmalloc pool */
+		irq_work_raise(c);
+}
+
+/* Called from BPF program or from sys_bpf syscall.
+ * In both cases migration is disabled.
+ */
+void notrace *bpf_mem_alloc(struct bpf_mem_alloc *ma, size_t size)
+{
+	int idx;
+	void *ret;
+
+	if (!size)
+		return ZERO_SIZE_PTR;
+
+	idx = bpf_mem_cache_idx(size + LLIST_NODE_SZ);
+	if (idx < 0)
+		return NULL;
+
+	ret = unit_alloc(this_cpu_ptr(ma->caches)->cache + idx);
+	return !ret ? NULL : ret + LLIST_NODE_SZ;
+}
+
+void notrace bpf_mem_free(struct bpf_mem_alloc *ma, void *ptr)
+{
+	int idx;
+
+	if (!ptr)
+		return;
+
+	idx = bpf_mem_cache_idx(ksize(ptr - LLIST_NODE_SZ));
+	if (idx < 0)
+		return;
+
+	unit_free(this_cpu_ptr(ma->caches)->cache + idx, ptr);
+}
+
+void notrace *bpf_mem_cache_alloc(struct bpf_mem_alloc *ma)
+{
+	void *ret;
+
+	ret = unit_alloc(this_cpu_ptr(ma->cache));
+	return !ret ? NULL : ret + LLIST_NODE_SZ;
+}
+
+void notrace bpf_mem_cache_free(struct bpf_mem_alloc *ma, void *ptr)
+{
+	if (!ptr)
+		return;
+
+	unit_free(this_cpu_ptr(ma->cache), ptr);
+}
diff --git a/kernel/bpf/mmap_unlock_work.h b/kernel/bpf/mmap_unlock_work.h
new file mode 100644
index 000000000..5d18d7d85
--- /dev/null
+++ b/kernel/bpf/mmap_unlock_work.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (c) 2021 Facebook
+ */
+
+#ifndef __MMAP_UNLOCK_WORK_H__
+#define __MMAP_UNLOCK_WORK_H__
+#include <linux/irq_work.h>
+
+/* irq_work to run mmap_read_unlock() in irq_work */
+struct mmap_unlock_irq_work {
+	struct irq_work irq_work;
+	struct mm_struct *mm;
+};
+
+DECLARE_PER_CPU(struct mmap_unlock_irq_work, mmap_unlock_work);
+
+/*
+ * We cannot do mmap_read_unlock() when the irq is disabled, because of
+ * risk to deadlock with rq_lock. To look up vma when the irqs are
+ * disabled, we need to run mmap_read_unlock() in irq_work. We use a
+ * percpu variable to do the irq_work. If the irq_work is already used
+ * by another lookup, we fall over.
+ */
+static inline bool bpf_mmap_unlock_get_irq_work(struct mmap_unlock_irq_work **work_ptr)
+{
+	struct mmap_unlock_irq_work *work = NULL;
+	bool irq_work_busy = false;
+
+	if (irqs_disabled()) {
+		if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {
+			work = this_cpu_ptr(&mmap_unlock_work);
+			if (irq_work_is_busy(&work->irq_work)) {
+				/* cannot queue more up_read, fallback */
+				irq_work_busy = true;
+			}
+		} else {
+			/*
+			 * PREEMPT_RT does not allow to trylock mmap sem in
+			 * interrupt disabled context. Force the fallback code.
+			 */
+			irq_work_busy = true;
+		}
+	}
+
+	*work_ptr = work;
+	return irq_work_busy;
+}
+
+static inline void bpf_mmap_unlock_mm(struct mmap_unlock_irq_work *work, struct mm_struct *mm)
+{
+	if (!work) {
+		mmap_read_unlock(mm);
+	} else {
+		work->mm = mm;
+
+		/* The lock will be released once we're out of interrupt
+		 * context. Tell lockdep that we've released it now so
+		 * it doesn't complain that we forgot to release it.
+		 */
+		rwsem_release(&mm->mmap_lock.dep_map, _RET_IP_);
+		irq_work_queue(&work->irq_work);
+	}
+}
+
+#endif /* __MMAP_UNLOCK_WORK_H__ */
diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c
new file mode 100644
index 000000000..868cc2c43
--- /dev/null
+++ b/kernel/bpf/net_namespace.c
@@ -0,0 +1,567 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <linux/bpf-netns.h>
+#include <linux/filter.h>
+#include <net/net_namespace.h>
+
+/*
+ * Functions to manage BPF programs attached to netns
+ */
+
+struct bpf_netns_link {
+	struct bpf_link	link;
+	enum bpf_attach_type type;
+	enum netns_bpf_attach_type netns_type;
+
+	/* We don't hold a ref to net in order to auto-detach the link
+	 * when netns is going away. Instead we rely on pernet
+	 * pre_exit callback to clear this pointer. Must be accessed
+	 * with netns_bpf_mutex held.
+	 */
+	struct net *net;
+	struct list_head node; /* node in list of links attached to net */
+};
+
+/* Protects updates to netns_bpf */
+DEFINE_MUTEX(netns_bpf_mutex);
+
+static void netns_bpf_attach_type_unneed(enum netns_bpf_attach_type type)
+{
+	switch (type) {
+#ifdef CONFIG_INET
+	case NETNS_BPF_SK_LOOKUP:
+		static_branch_dec(&bpf_sk_lookup_enabled);
+		break;
+#endif
+	default:
+		break;
+	}
+}
+
+static void netns_bpf_attach_type_need(enum netns_bpf_attach_type type)
+{
+	switch (type) {
+#ifdef CONFIG_INET
+	case NETNS_BPF_SK_LOOKUP:
+		static_branch_inc(&bpf_sk_lookup_enabled);
+		break;
+#endif
+	default:
+		break;
+	}
+}
+
+/* Must be called with netns_bpf_mutex held. */
+static void netns_bpf_run_array_detach(struct net *net,
+				       enum netns_bpf_attach_type type)
+{
+	struct bpf_prog_array *run_array;
+
+	run_array = rcu_replace_pointer(net->bpf.run_array[type], NULL,
+					lockdep_is_held(&netns_bpf_mutex));
+	bpf_prog_array_free(run_array);
+}
+
+static int link_index(struct net *net, enum netns_bpf_attach_type type,
+		      struct bpf_netns_link *link)
+{
+	struct bpf_netns_link *pos;
+	int i = 0;
+
+	list_for_each_entry(pos, &net->bpf.links[type], node) {
+		if (pos == link)
+			return i;
+		i++;
+	}
+	return -ENOENT;
+}
+
+static int link_count(struct net *net, enum netns_bpf_attach_type type)
+{
+	struct list_head *pos;
+	int i = 0;
+
+	list_for_each(pos, &net->bpf.links[type])
+		i++;
+	return i;
+}
+
+static void fill_prog_array(struct net *net, enum netns_bpf_attach_type type,
+			    struct bpf_prog_array *prog_array)
+{
+	struct bpf_netns_link *pos;
+	unsigned int i = 0;
+
+	list_for_each_entry(pos, &net->bpf.links[type], node) {
+		prog_array->items[i].prog = pos->link.prog;
+		i++;
+	}
+}
+
+static void bpf_netns_link_release(struct bpf_link *link)
+{
+	struct bpf_netns_link *net_link =
+		container_of(link, struct bpf_netns_link, link);
+	enum netns_bpf_attach_type type = net_link->netns_type;
+	struct bpf_prog_array *old_array, *new_array;
+	struct net *net;
+	int cnt, idx;
+
+	mutex_lock(&netns_bpf_mutex);
+
+	/* We can race with cleanup_net, but if we see a non-NULL
+	 * struct net pointer, pre_exit has not run yet and wait for
+	 * netns_bpf_mutex.
+	 */
+	net = net_link->net;
+	if (!net)
+		goto out_unlock;
+
+	/* Mark attach point as unused */
+	netns_bpf_attach_type_unneed(type);
+
+	/* Remember link position in case of safe delete */
+	idx = link_index(net, type, net_link);
+	list_del(&net_link->node);
+
+	cnt = link_count(net, type);
+	if (!cnt) {
+		netns_bpf_run_array_detach(net, type);
+		goto out_unlock;
+	}
+
+	old_array = rcu_dereference_protected(net->bpf.run_array[type],
+					      lockdep_is_held(&netns_bpf_mutex));
+	new_array = bpf_prog_array_alloc(cnt, GFP_KERNEL);
+	if (!new_array) {
+		WARN_ON(bpf_prog_array_delete_safe_at(old_array, idx));
+		goto out_unlock;
+	}
+	fill_prog_array(net, type, new_array);
+	rcu_assign_pointer(net->bpf.run_array[type], new_array);
+	bpf_prog_array_free(old_array);
+
+out_unlock:
+	net_link->net = NULL;
+	mutex_unlock(&netns_bpf_mutex);
+}
+
+static int bpf_netns_link_detach(struct bpf_link *link)
+{
+	bpf_netns_link_release(link);
+	return 0;
+}
+
+static void bpf_netns_link_dealloc(struct bpf_link *link)
+{
+	struct bpf_netns_link *net_link =
+		container_of(link, struct bpf_netns_link, link);
+
+	kfree(net_link);
+}
+
+static int bpf_netns_link_update_prog(struct bpf_link *link,
+				      struct bpf_prog *new_prog,
+				      struct bpf_prog *old_prog)
+{
+	struct bpf_netns_link *net_link =
+		container_of(link, struct bpf_netns_link, link);
+	enum netns_bpf_attach_type type = net_link->netns_type;
+	struct bpf_prog_array *run_array;
+	struct net *net;
+	int idx, ret;
+
+	if (old_prog && old_prog != link->prog)
+		return -EPERM;
+	if (new_prog->type != link->prog->type)
+		return -EINVAL;
+
+	mutex_lock(&netns_bpf_mutex);
+
+	net = net_link->net;
+	if (!net || !check_net(net)) {
+		/* Link auto-detached or netns dying */
+		ret = -ENOLINK;
+		goto out_unlock;
+	}
+
+	run_array = rcu_dereference_protected(net->bpf.run_array[type],
+					      lockdep_is_held(&netns_bpf_mutex));
+	idx = link_index(net, type, net_link);
+	ret = bpf_prog_array_update_at(run_array, idx, new_prog);
+	if (ret)
+		goto out_unlock;
+
+	old_prog = xchg(&link->prog, new_prog);
+	bpf_prog_put(old_prog);
+
+out_unlock:
+	mutex_unlock(&netns_bpf_mutex);
+	return ret;
+}
+
+static int bpf_netns_link_fill_info(const struct bpf_link *link,
+				    struct bpf_link_info *info)
+{
+	const struct bpf_netns_link *net_link =
+		container_of(link, struct bpf_netns_link, link);
+	unsigned int inum = 0;
+	struct net *net;
+
+	mutex_lock(&netns_bpf_mutex);
+	net = net_link->net;
+	if (net && check_net(net))
+		inum = net->ns.inum;
+	mutex_unlock(&netns_bpf_mutex);
+
+	info->netns.netns_ino = inum;
+	info->netns.attach_type = net_link->type;
+	return 0;
+}
+
+static void bpf_netns_link_show_fdinfo(const struct bpf_link *link,
+				       struct seq_file *seq)
+{
+	struct bpf_link_info info = {};
+
+	bpf_netns_link_fill_info(link, &info);
+	seq_printf(seq,
+		   "netns_ino:\t%u\n"
+		   "attach_type:\t%u\n",
+		   info.netns.netns_ino,
+		   info.netns.attach_type);
+}
+
+static const struct bpf_link_ops bpf_netns_link_ops = {
+	.release = bpf_netns_link_release,
+	.dealloc = bpf_netns_link_dealloc,
+	.detach = bpf_netns_link_detach,
+	.update_prog = bpf_netns_link_update_prog,
+	.fill_link_info = bpf_netns_link_fill_info,
+	.show_fdinfo = bpf_netns_link_show_fdinfo,
+};
+
+/* Must be called with netns_bpf_mutex held. */
+static int __netns_bpf_prog_query(const union bpf_attr *attr,
+				  union bpf_attr __user *uattr,
+				  struct net *net,
+				  enum netns_bpf_attach_type type)
+{
+	__u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
+	struct bpf_prog_array *run_array;
+	u32 prog_cnt = 0, flags = 0;
+
+	run_array = rcu_dereference_protected(net->bpf.run_array[type],
+					      lockdep_is_held(&netns_bpf_mutex));
+	if (run_array)
+		prog_cnt = bpf_prog_array_length(run_array);
+
+	if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
+		return -EFAULT;
+	if (copy_to_user(&uattr->query.prog_cnt, &prog_cnt, sizeof(prog_cnt)))
+		return -EFAULT;
+	if (!attr->query.prog_cnt || !prog_ids || !prog_cnt)
+		return 0;
+
+	return bpf_prog_array_copy_to_user(run_array, prog_ids,
+					   attr->query.prog_cnt);
+}
+
+int netns_bpf_prog_query(const union bpf_attr *attr,
+			 union bpf_attr __user *uattr)
+{
+	enum netns_bpf_attach_type type;
+	struct net *net;
+	int ret;
+
+	if (attr->query.query_flags)
+		return -EINVAL;
+
+	type = to_netns_bpf_attach_type(attr->query.attach_type);
+	if (type < 0)
+		return -EINVAL;
+
+	net = get_net_ns_by_fd(attr->query.target_fd);
+	if (IS_ERR(net))
+		return PTR_ERR(net);
+
+	mutex_lock(&netns_bpf_mutex);
+	ret = __netns_bpf_prog_query(attr, uattr, net, type);
+	mutex_unlock(&netns_bpf_mutex);
+
+	put_net(net);
+	return ret;
+}
+
+int netns_bpf_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)
+{
+	struct bpf_prog_array *run_array;
+	enum netns_bpf_attach_type type;
+	struct bpf_prog *attached;
+	struct net *net;
+	int ret;
+
+	if (attr->target_fd || attr->attach_flags || attr->replace_bpf_fd)
+		return -EINVAL;
+
+	type = to_netns_bpf_attach_type(attr->attach_type);
+	if (type < 0)
+		return -EINVAL;
+
+	net = current->nsproxy->net_ns;
+	mutex_lock(&netns_bpf_mutex);
+
+	/* Attaching prog directly is not compatible with links */
+	if (!list_empty(&net->bpf.links[type])) {
+		ret = -EEXIST;
+		goto out_unlock;
+	}
+
+	switch (type) {
+	case NETNS_BPF_FLOW_DISSECTOR:
+		ret = flow_dissector_bpf_prog_attach_check(net, prog);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	if (ret)
+		goto out_unlock;
+
+	attached = net->bpf.progs[type];
+	if (attached == prog) {
+		/* The same program cannot be attached twice */
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	run_array = rcu_dereference_protected(net->bpf.run_array[type],
+					      lockdep_is_held(&netns_bpf_mutex));
+	if (run_array) {
+		WRITE_ONCE(run_array->items[0].prog, prog);
+	} else {
+		run_array = bpf_prog_array_alloc(1, GFP_KERNEL);
+		if (!run_array) {
+			ret = -ENOMEM;
+			goto out_unlock;
+		}
+		run_array->items[0].prog = prog;
+		rcu_assign_pointer(net->bpf.run_array[type], run_array);
+	}
+
+	net->bpf.progs[type] = prog;
+	if (attached)
+		bpf_prog_put(attached);
+
+out_unlock:
+	mutex_unlock(&netns_bpf_mutex);
+
+	return ret;
+}
+
+/* Must be called with netns_bpf_mutex held. */
+static int __netns_bpf_prog_detach(struct net *net,
+				   enum netns_bpf_attach_type type,
+				   struct bpf_prog *old)
+{
+	struct bpf_prog *attached;
+
+	/* Progs attached via links cannot be detached */
+	if (!list_empty(&net->bpf.links[type]))
+		return -EINVAL;
+
+	attached = net->bpf.progs[type];
+	if (!attached || attached != old)
+		return -ENOENT;
+	netns_bpf_run_array_detach(net, type);
+	net->bpf.progs[type] = NULL;
+	bpf_prog_put(attached);
+	return 0;
+}
+
+int netns_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype)
+{
+	enum netns_bpf_attach_type type;
+	struct bpf_prog *prog;
+	int ret;
+
+	if (attr->target_fd)
+		return -EINVAL;
+
+	type = to_netns_bpf_attach_type(attr->attach_type);
+	if (type < 0)
+		return -EINVAL;
+
+	prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
+	mutex_lock(&netns_bpf_mutex);
+	ret = __netns_bpf_prog_detach(current->nsproxy->net_ns, type, prog);
+	mutex_unlock(&netns_bpf_mutex);
+
+	bpf_prog_put(prog);
+
+	return ret;
+}
+
+static int netns_bpf_max_progs(enum netns_bpf_attach_type type)
+{
+	switch (type) {
+	case NETNS_BPF_FLOW_DISSECTOR:
+		return 1;
+	case NETNS_BPF_SK_LOOKUP:
+		return 64;
+	default:
+		return 0;
+	}
+}
+
+static int netns_bpf_link_attach(struct net *net, struct bpf_link *link,
+				 enum netns_bpf_attach_type type)
+{
+	struct bpf_netns_link *net_link =
+		container_of(link, struct bpf_netns_link, link);
+	struct bpf_prog_array *run_array;
+	int cnt, err;
+
+	mutex_lock(&netns_bpf_mutex);
+
+	cnt = link_count(net, type);
+	if (cnt >= netns_bpf_max_progs(type)) {
+		err = -E2BIG;
+		goto out_unlock;
+	}
+	/* Links are not compatible with attaching prog directly */
+	if (net->bpf.progs[type]) {
+		err = -EEXIST;
+		goto out_unlock;
+	}
+
+	switch (type) {
+	case NETNS_BPF_FLOW_DISSECTOR:
+		err = flow_dissector_bpf_prog_attach_check(net, link->prog);
+		break;
+	case NETNS_BPF_SK_LOOKUP:
+		err = 0; /* nothing to check */
+		break;
+	default:
+		err = -EINVAL;
+		break;
+	}
+	if (err)
+		goto out_unlock;
+
+	run_array = bpf_prog_array_alloc(cnt + 1, GFP_KERNEL);
+	if (!run_array) {
+		err = -ENOMEM;
+		goto out_unlock;
+	}
+
+	list_add_tail(&net_link->node, &net->bpf.links[type]);
+
+	fill_prog_array(net, type, run_array);
+	run_array = rcu_replace_pointer(net->bpf.run_array[type], run_array,
+					lockdep_is_held(&netns_bpf_mutex));
+	bpf_prog_array_free(run_array);
+
+	/* Mark attach point as used */
+	netns_bpf_attach_type_need(type);
+
+out_unlock:
+	mutex_unlock(&netns_bpf_mutex);
+	return err;
+}
+
+int netns_bpf_link_create(const union bpf_attr *attr, struct bpf_prog *prog)
+{
+	enum netns_bpf_attach_type netns_type;
+	struct bpf_link_primer link_primer;
+	struct bpf_netns_link *net_link;
+	enum bpf_attach_type type;
+	struct net *net;
+	int err;
+
+	if (attr->link_create.flags)
+		return -EINVAL;
+
+	type = attr->link_create.attach_type;
+	netns_type = to_netns_bpf_attach_type(type);
+	if (netns_type < 0)
+		return -EINVAL;
+
+	net = get_net_ns_by_fd(attr->link_create.target_fd);
+	if (IS_ERR(net))
+		return PTR_ERR(net);
+
+	net_link = kzalloc(sizeof(*net_link), GFP_USER);
+	if (!net_link) {
+		err = -ENOMEM;
+		goto out_put_net;
+	}
+	bpf_link_init(&net_link->link, BPF_LINK_TYPE_NETNS,
+		      &bpf_netns_link_ops, prog);
+	net_link->net = net;
+	net_link->type = type;
+	net_link->netns_type = netns_type;
+
+	err = bpf_link_prime(&net_link->link, &link_primer);
+	if (err) {
+		kfree(net_link);
+		goto out_put_net;
+	}
+
+	err = netns_bpf_link_attach(net, &net_link->link, netns_type);
+	if (err) {
+		bpf_link_cleanup(&link_primer);
+		goto out_put_net;
+	}
+
+	put_net(net);
+	return bpf_link_settle(&link_primer);
+
+out_put_net:
+	put_net(net);
+	return err;
+}
+
+static int __net_init netns_bpf_pernet_init(struct net *net)
+{
+	int type;
+
+	for (type = 0; type < MAX_NETNS_BPF_ATTACH_TYPE; type++)
+		INIT_LIST_HEAD(&net->bpf.links[type]);
+
+	return 0;
+}
+
+static void __net_exit netns_bpf_pernet_pre_exit(struct net *net)
+{
+	enum netns_bpf_attach_type type;
+	struct bpf_netns_link *net_link;
+
+	mutex_lock(&netns_bpf_mutex);
+	for (type = 0; type < MAX_NETNS_BPF_ATTACH_TYPE; type++) {
+		netns_bpf_run_array_detach(net, type);
+		list_for_each_entry(net_link, &net->bpf.links[type], node) {
+			net_link->net = NULL; /* auto-detach link */
+			netns_bpf_attach_type_unneed(type);
+		}
+		if (net->bpf.progs[type])
+			bpf_prog_put(net->bpf.progs[type]);
+	}
+	mutex_unlock(&netns_bpf_mutex);
+}
+
+static struct pernet_operations netns_bpf_pernet_ops __net_initdata = {
+	.init = netns_bpf_pernet_init,
+	.pre_exit = netns_bpf_pernet_pre_exit,
+};
+
+static int __init netns_bpf_init(void)
+{
+	return register_pernet_subsys(&netns_bpf_pernet_ops);
+}
+
+subsys_initcall(netns_bpf_init);
diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
new file mode 100644
index 000000000..190d9f9dc
--- /dev/null
+++ b/kernel/bpf/offload.c
@@ -0,0 +1,709 @@
+/*
+ * Copyright (C) 2017-2018 Netronome Systems, Inc.
+ *
+ * This software is licensed under the GNU General License Version 2,
+ * June 1991 as shown in the file COPYING in the top-level directory of this
+ * source tree.
+ *
+ * THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
+ * WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE
+ * OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
+ * THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+ */
+
+#include <linux/bpf.h>
+#include <linux/bpf_verifier.h>
+#include <linux/bug.h>
+#include <linux/kdev_t.h>
+#include <linux/list.h>
+#include <linux/lockdep.h>
+#include <linux/netdevice.h>
+#include <linux/printk.h>
+#include <linux/proc_ns.h>
+#include <linux/rhashtable.h>
+#include <linux/rtnetlink.h>
+#include <linux/rwsem.h>
+
+/* Protects offdevs, members of bpf_offload_netdev and offload members
+ * of all progs.
+ * RTNL lock cannot be taken when holding this lock.
+ */
+static DECLARE_RWSEM(bpf_devs_lock);
+
+struct bpf_offload_dev {
+	const struct bpf_prog_offload_ops *ops;
+	struct list_head netdevs;
+	void *priv;
+};
+
+struct bpf_offload_netdev {
+	struct rhash_head l;
+	struct net_device *netdev;
+	struct bpf_offload_dev *offdev;
+	struct list_head progs;
+	struct list_head maps;
+	struct list_head offdev_netdevs;
+};
+
+static const struct rhashtable_params offdevs_params = {
+	.nelem_hint		= 4,
+	.key_len		= sizeof(struct net_device *),
+	.key_offset		= offsetof(struct bpf_offload_netdev, netdev),
+	.head_offset		= offsetof(struct bpf_offload_netdev, l),
+	.automatic_shrinking	= true,
+};
+
+static struct rhashtable offdevs;
+static bool offdevs_inited;
+
+static int bpf_dev_offload_check(struct net_device *netdev)
+{
+	if (!netdev)
+		return -EINVAL;
+	if (!netdev->netdev_ops->ndo_bpf)
+		return -EOPNOTSUPP;
+	return 0;
+}
+
+static struct bpf_offload_netdev *
+bpf_offload_find_netdev(struct net_device *netdev)
+{
+	lockdep_assert_held(&bpf_devs_lock);
+
+	if (!offdevs_inited)
+		return NULL;
+	return rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
+}
+
+int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
+{
+	struct bpf_offload_netdev *ondev;
+	struct bpf_prog_offload *offload;
+	int err;
+
+	if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS &&
+	    attr->prog_type != BPF_PROG_TYPE_XDP)
+		return -EINVAL;
+
+	if (attr->prog_flags)
+		return -EINVAL;
+
+	offload = kzalloc(sizeof(*offload), GFP_USER);
+	if (!offload)
+		return -ENOMEM;
+
+	offload->prog = prog;
+
+	offload->netdev = dev_get_by_index(current->nsproxy->net_ns,
+					   attr->prog_ifindex);
+	err = bpf_dev_offload_check(offload->netdev);
+	if (err)
+		goto err_maybe_put;
+
+	down_write(&bpf_devs_lock);
+	ondev = bpf_offload_find_netdev(offload->netdev);
+	if (!ondev) {
+		err = -EINVAL;
+		goto err_unlock;
+	}
+	offload->offdev = ondev->offdev;
+	prog->aux->offload = offload;
+	list_add_tail(&offload->offloads, &ondev->progs);
+	dev_put(offload->netdev);
+	up_write(&bpf_devs_lock);
+
+	return 0;
+err_unlock:
+	up_write(&bpf_devs_lock);
+err_maybe_put:
+	if (offload->netdev)
+		dev_put(offload->netdev);
+	kfree(offload);
+	return err;
+}
+
+int bpf_prog_offload_verifier_prep(struct bpf_prog *prog)
+{
+	struct bpf_prog_offload *offload;
+	int ret = -ENODEV;
+
+	down_read(&bpf_devs_lock);
+	offload = prog->aux->offload;
+	if (offload) {
+		ret = offload->offdev->ops->prepare(prog);
+		offload->dev_state = !ret;
+	}
+	up_read(&bpf_devs_lock);
+
+	return ret;
+}
+
+int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
+				 int insn_idx, int prev_insn_idx)
+{
+	struct bpf_prog_offload *offload;
+	int ret = -ENODEV;
+
+	down_read(&bpf_devs_lock);
+	offload = env->prog->aux->offload;
+	if (offload)
+		ret = offload->offdev->ops->insn_hook(env, insn_idx,
+						      prev_insn_idx);
+	up_read(&bpf_devs_lock);
+
+	return ret;
+}
+
+int bpf_prog_offload_finalize(struct bpf_verifier_env *env)
+{
+	struct bpf_prog_offload *offload;
+	int ret = -ENODEV;
+
+	down_read(&bpf_devs_lock);
+	offload = env->prog->aux->offload;
+	if (offload) {
+		if (offload->offdev->ops->finalize)
+			ret = offload->offdev->ops->finalize(env);
+		else
+			ret = 0;
+	}
+	up_read(&bpf_devs_lock);
+
+	return ret;
+}
+
+void
+bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,
+			      struct bpf_insn *insn)
+{
+	const struct bpf_prog_offload_ops *ops;
+	struct bpf_prog_offload *offload;
+	int ret = -EOPNOTSUPP;
+
+	down_read(&bpf_devs_lock);
+	offload = env->prog->aux->offload;
+	if (offload) {
+		ops = offload->offdev->ops;
+		if (!offload->opt_failed && ops->replace_insn)
+			ret = ops->replace_insn(env, off, insn);
+		offload->opt_failed |= ret;
+	}
+	up_read(&bpf_devs_lock);
+}
+
+void
+bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
+{
+	struct bpf_prog_offload *offload;
+	int ret = -EOPNOTSUPP;
+
+	down_read(&bpf_devs_lock);
+	offload = env->prog->aux->offload;
+	if (offload) {
+		if (!offload->opt_failed && offload->offdev->ops->remove_insns)
+			ret = offload->offdev->ops->remove_insns(env, off, cnt);
+		offload->opt_failed |= ret;
+	}
+	up_read(&bpf_devs_lock);
+}
+
+static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
+{
+	struct bpf_prog_offload *offload = prog->aux->offload;
+
+	if (offload->dev_state)
+		offload->offdev->ops->destroy(prog);
+
+	list_del_init(&offload->offloads);
+	kfree(offload);
+	prog->aux->offload = NULL;
+}
+
+void bpf_prog_offload_destroy(struct bpf_prog *prog)
+{
+	down_write(&bpf_devs_lock);
+	if (prog->aux->offload)
+		__bpf_prog_offload_destroy(prog);
+	up_write(&bpf_devs_lock);
+}
+
+static int bpf_prog_offload_translate(struct bpf_prog *prog)
+{
+	struct bpf_prog_offload *offload;
+	int ret = -ENODEV;
+
+	down_read(&bpf_devs_lock);
+	offload = prog->aux->offload;
+	if (offload)
+		ret = offload->offdev->ops->translate(prog);
+	up_read(&bpf_devs_lock);
+
+	return ret;
+}
+
+static unsigned int bpf_prog_warn_on_exec(const void *ctx,
+					  const struct bpf_insn *insn)
+{
+	WARN(1, "attempt to execute device eBPF program on the host!");
+	return 0;
+}
+
+int bpf_prog_offload_compile(struct bpf_prog *prog)
+{
+	prog->bpf_func = bpf_prog_warn_on_exec;
+
+	return bpf_prog_offload_translate(prog);
+}
+
+struct ns_get_path_bpf_prog_args {
+	struct bpf_prog *prog;
+	struct bpf_prog_info *info;
+};
+
+static struct ns_common *bpf_prog_offload_info_fill_ns(void *private_data)
+{
+	struct ns_get_path_bpf_prog_args *args = private_data;
+	struct bpf_prog_aux *aux = args->prog->aux;
+	struct ns_common *ns;
+	struct net *net;
+
+	rtnl_lock();
+	down_read(&bpf_devs_lock);
+
+	if (aux->offload) {
+		args->info->ifindex = aux->offload->netdev->ifindex;
+		net = dev_net(aux->offload->netdev);
+		get_net(net);
+		ns = &net->ns;
+	} else {
+		args->info->ifindex = 0;
+		ns = NULL;
+	}
+
+	up_read(&bpf_devs_lock);
+	rtnl_unlock();
+
+	return ns;
+}
+
+int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
+			       struct bpf_prog *prog)
+{
+	struct ns_get_path_bpf_prog_args args = {
+		.prog	= prog,
+		.info	= info,
+	};
+	struct bpf_prog_aux *aux = prog->aux;
+	struct inode *ns_inode;
+	struct path ns_path;
+	char __user *uinsns;
+	int res;
+	u32 ulen;
+
+	res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args);
+	if (res) {
+		if (!info->ifindex)
+			return -ENODEV;
+		return res;
+	}
+
+	down_read(&bpf_devs_lock);
+
+	if (!aux->offload) {
+		up_read(&bpf_devs_lock);
+		return -ENODEV;
+	}
+
+	ulen = info->jited_prog_len;
+	info->jited_prog_len = aux->offload->jited_len;
+	if (info->jited_prog_len && ulen) {
+		uinsns = u64_to_user_ptr(info->jited_prog_insns);
+		ulen = min_t(u32, info->jited_prog_len, ulen);
+		if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {
+			up_read(&bpf_devs_lock);
+			return -EFAULT;
+		}
+	}
+
+	up_read(&bpf_devs_lock);
+
+	ns_inode = ns_path.dentry->d_inode;
+	info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
+	info->netns_ino = ns_inode->i_ino;
+	path_put(&ns_path);
+
+	return 0;
+}
+
+const struct bpf_prog_ops bpf_offload_prog_ops = {
+};
+
+static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap,
+			       enum bpf_netdev_command cmd)
+{
+	struct netdev_bpf data = {};
+	struct net_device *netdev;
+
+	ASSERT_RTNL();
+
+	data.command = cmd;
+	data.offmap = offmap;
+	/* Caller must make sure netdev is valid */
+	netdev = offmap->netdev;
+
+	return netdev->netdev_ops->ndo_bpf(netdev, &data);
+}
+
+struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr)
+{
+	struct net *net = current->nsproxy->net_ns;
+	struct bpf_offload_netdev *ondev;
+	struct bpf_offloaded_map *offmap;
+	int err;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return ERR_PTR(-EPERM);
+	if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
+	    attr->map_type != BPF_MAP_TYPE_HASH)
+		return ERR_PTR(-EINVAL);
+
+	offmap = bpf_map_area_alloc(sizeof(*offmap), NUMA_NO_NODE);
+	if (!offmap)
+		return ERR_PTR(-ENOMEM);
+
+	bpf_map_init_from_attr(&offmap->map, attr);
+
+	rtnl_lock();
+	down_write(&bpf_devs_lock);
+	offmap->netdev = __dev_get_by_index(net, attr->map_ifindex);
+	err = bpf_dev_offload_check(offmap->netdev);
+	if (err)
+		goto err_unlock;
+
+	ondev = bpf_offload_find_netdev(offmap->netdev);
+	if (!ondev) {
+		err = -EINVAL;
+		goto err_unlock;
+	}
+
+	err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC);
+	if (err)
+		goto err_unlock;
+
+	list_add_tail(&offmap->offloads, &ondev->maps);
+	up_write(&bpf_devs_lock);
+	rtnl_unlock();
+
+	return &offmap->map;
+
+err_unlock:
+	up_write(&bpf_devs_lock);
+	rtnl_unlock();
+	bpf_map_area_free(offmap);
+	return ERR_PTR(err);
+}
+
+static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap)
+{
+	WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE));
+	/* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */
+	bpf_map_free_id(&offmap->map, true);
+	list_del_init(&offmap->offloads);
+	offmap->netdev = NULL;
+}
+
+void bpf_map_offload_map_free(struct bpf_map *map)
+{
+	struct bpf_offloaded_map *offmap = map_to_offmap(map);
+
+	rtnl_lock();
+	down_write(&bpf_devs_lock);
+	if (offmap->netdev)
+		__bpf_map_offload_destroy(offmap);
+	up_write(&bpf_devs_lock);
+	rtnl_unlock();
+
+	bpf_map_area_free(offmap);
+}
+
+int bpf_map_offload_lookup_elem(struct bpf_map *map, void *key, void *value)
+{
+	struct bpf_offloaded_map *offmap = map_to_offmap(map);
+	int ret = -ENODEV;
+
+	down_read(&bpf_devs_lock);
+	if (offmap->netdev)
+		ret = offmap->dev_ops->map_lookup_elem(offmap, key, value);
+	up_read(&bpf_devs_lock);
+
+	return ret;
+}
+
+int bpf_map_offload_update_elem(struct bpf_map *map,
+				void *key, void *value, u64 flags)
+{
+	struct bpf_offloaded_map *offmap = map_to_offmap(map);
+	int ret = -ENODEV;
+
+	if (unlikely(flags > BPF_EXIST))
+		return -EINVAL;
+
+	down_read(&bpf_devs_lock);
+	if (offmap->netdev)
+		ret = offmap->dev_ops->map_update_elem(offmap, key, value,
+						       flags);
+	up_read(&bpf_devs_lock);
+
+	return ret;
+}
+
+int bpf_map_offload_delete_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_offloaded_map *offmap = map_to_offmap(map);
+	int ret = -ENODEV;
+
+	down_read(&bpf_devs_lock);
+	if (offmap->netdev)
+		ret = offmap->dev_ops->map_delete_elem(offmap, key);
+	up_read(&bpf_devs_lock);
+
+	return ret;
+}
+
+int bpf_map_offload_get_next_key(struct bpf_map *map, void *key, void *next_key)
+{
+	struct bpf_offloaded_map *offmap = map_to_offmap(map);
+	int ret = -ENODEV;
+
+	down_read(&bpf_devs_lock);
+	if (offmap->netdev)
+		ret = offmap->dev_ops->map_get_next_key(offmap, key, next_key);
+	up_read(&bpf_devs_lock);
+
+	return ret;
+}
+
+struct ns_get_path_bpf_map_args {
+	struct bpf_offloaded_map *offmap;
+	struct bpf_map_info *info;
+};
+
+static struct ns_common *bpf_map_offload_info_fill_ns(void *private_data)
+{
+	struct ns_get_path_bpf_map_args *args = private_data;
+	struct ns_common *ns;
+	struct net *net;
+
+	rtnl_lock();
+	down_read(&bpf_devs_lock);
+
+	if (args->offmap->netdev) {
+		args->info->ifindex = args->offmap->netdev->ifindex;
+		net = dev_net(args->offmap->netdev);
+		get_net(net);
+		ns = &net->ns;
+	} else {
+		args->info->ifindex = 0;
+		ns = NULL;
+	}
+
+	up_read(&bpf_devs_lock);
+	rtnl_unlock();
+
+	return ns;
+}
+
+int bpf_map_offload_info_fill(struct bpf_map_info *info, struct bpf_map *map)
+{
+	struct ns_get_path_bpf_map_args args = {
+		.offmap	= map_to_offmap(map),
+		.info	= info,
+	};
+	struct inode *ns_inode;
+	struct path ns_path;
+	int res;
+
+	res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args);
+	if (res) {
+		if (!info->ifindex)
+			return -ENODEV;
+		return res;
+	}
+
+	ns_inode = ns_path.dentry->d_inode;
+	info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
+	info->netns_ino = ns_inode->i_ino;
+	path_put(&ns_path);
+
+	return 0;
+}
+
+static bool __bpf_offload_dev_match(struct bpf_prog *prog,
+				    struct net_device *netdev)
+{
+	struct bpf_offload_netdev *ondev1, *ondev2;
+	struct bpf_prog_offload *offload;
+
+	if (!bpf_prog_is_dev_bound(prog->aux))
+		return false;
+
+	offload = prog->aux->offload;
+	if (!offload)
+		return false;
+	if (offload->netdev == netdev)
+		return true;
+
+	ondev1 = bpf_offload_find_netdev(offload->netdev);
+	ondev2 = bpf_offload_find_netdev(netdev);
+
+	return ondev1 && ondev2 && ondev1->offdev == ondev2->offdev;
+}
+
+bool bpf_offload_dev_match(struct bpf_prog *prog, struct net_device *netdev)
+{
+	bool ret;
+
+	down_read(&bpf_devs_lock);
+	ret = __bpf_offload_dev_match(prog, netdev);
+	up_read(&bpf_devs_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(bpf_offload_dev_match);
+
+bool bpf_offload_prog_map_match(struct bpf_prog *prog, struct bpf_map *map)
+{
+	struct bpf_offloaded_map *offmap;
+	bool ret;
+
+	if (!bpf_map_is_dev_bound(map))
+		return bpf_map_offload_neutral(map);
+	offmap = map_to_offmap(map);
+
+	down_read(&bpf_devs_lock);
+	ret = __bpf_offload_dev_match(prog, offmap->netdev);
+	up_read(&bpf_devs_lock);
+
+	return ret;
+}
+
+int bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev,
+				    struct net_device *netdev)
+{
+	struct bpf_offload_netdev *ondev;
+	int err;
+
+	ondev = kzalloc(sizeof(*ondev), GFP_KERNEL);
+	if (!ondev)
+		return -ENOMEM;
+
+	ondev->netdev = netdev;
+	ondev->offdev = offdev;
+	INIT_LIST_HEAD(&ondev->progs);
+	INIT_LIST_HEAD(&ondev->maps);
+
+	down_write(&bpf_devs_lock);
+	err = rhashtable_insert_fast(&offdevs, &ondev->l, offdevs_params);
+	if (err) {
+		netdev_warn(netdev, "failed to register for BPF offload\n");
+		goto err_unlock_free;
+	}
+
+	list_add(&ondev->offdev_netdevs, &offdev->netdevs);
+	up_write(&bpf_devs_lock);
+	return 0;
+
+err_unlock_free:
+	up_write(&bpf_devs_lock);
+	kfree(ondev);
+	return err;
+}
+EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_register);
+
+void bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev,
+				       struct net_device *netdev)
+{
+	struct bpf_offload_netdev *ondev, *altdev;
+	struct bpf_offloaded_map *offmap, *mtmp;
+	struct bpf_prog_offload *offload, *ptmp;
+
+	ASSERT_RTNL();
+
+	down_write(&bpf_devs_lock);
+	ondev = rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
+	if (WARN_ON(!ondev))
+		goto unlock;
+
+	WARN_ON(rhashtable_remove_fast(&offdevs, &ondev->l, offdevs_params));
+	list_del(&ondev->offdev_netdevs);
+
+	/* Try to move the objects to another netdev of the device */
+	altdev = list_first_entry_or_null(&offdev->netdevs,
+					  struct bpf_offload_netdev,
+					  offdev_netdevs);
+	if (altdev) {
+		list_for_each_entry(offload, &ondev->progs, offloads)
+			offload->netdev = altdev->netdev;
+		list_splice_init(&ondev->progs, &altdev->progs);
+
+		list_for_each_entry(offmap, &ondev->maps, offloads)
+			offmap->netdev = altdev->netdev;
+		list_splice_init(&ondev->maps, &altdev->maps);
+	} else {
+		list_for_each_entry_safe(offload, ptmp, &ondev->progs, offloads)
+			__bpf_prog_offload_destroy(offload->prog);
+		list_for_each_entry_safe(offmap, mtmp, &ondev->maps, offloads)
+			__bpf_map_offload_destroy(offmap);
+	}
+
+	WARN_ON(!list_empty(&ondev->progs));
+	WARN_ON(!list_empty(&ondev->maps));
+	kfree(ondev);
+unlock:
+	up_write(&bpf_devs_lock);
+}
+EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_unregister);
+
+struct bpf_offload_dev *
+bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops, void *priv)
+{
+	struct bpf_offload_dev *offdev;
+	int err;
+
+	down_write(&bpf_devs_lock);
+	if (!offdevs_inited) {
+		err = rhashtable_init(&offdevs, &offdevs_params);
+		if (err) {
+			up_write(&bpf_devs_lock);
+			return ERR_PTR(err);
+		}
+		offdevs_inited = true;
+	}
+	up_write(&bpf_devs_lock);
+
+	offdev = kzalloc(sizeof(*offdev), GFP_KERNEL);
+	if (!offdev)
+		return ERR_PTR(-ENOMEM);
+
+	offdev->ops = ops;
+	offdev->priv = priv;
+	INIT_LIST_HEAD(&offdev->netdevs);
+
+	return offdev;
+}
+EXPORT_SYMBOL_GPL(bpf_offload_dev_create);
+
+void bpf_offload_dev_destroy(struct bpf_offload_dev *offdev)
+{
+	WARN_ON(!list_empty(&offdev->netdevs));
+	kfree(offdev);
+}
+EXPORT_SYMBOL_GPL(bpf_offload_dev_destroy);
+
+void *bpf_offload_dev_priv(struct bpf_offload_dev *offdev)
+{
+	return offdev->priv;
+}
+EXPORT_SYMBOL_GPL(bpf_offload_dev_priv);
diff --git a/kernel/bpf/percpu_freelist.c b/kernel/bpf/percpu_freelist.c
new file mode 100644
index 000000000..034cf87b5
--- /dev/null
+++ b/kernel/bpf/percpu_freelist.c
@@ -0,0 +1,200 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2016 Facebook
+ */
+#include "percpu_freelist.h"
+
+int pcpu_freelist_init(struct pcpu_freelist *s)
+{
+	int cpu;
+
+	s->freelist = alloc_percpu(struct pcpu_freelist_head);
+	if (!s->freelist)
+		return -ENOMEM;
+
+	for_each_possible_cpu(cpu) {
+		struct pcpu_freelist_head *head = per_cpu_ptr(s->freelist, cpu);
+
+		raw_spin_lock_init(&head->lock);
+		head->first = NULL;
+	}
+	raw_spin_lock_init(&s->extralist.lock);
+	s->extralist.first = NULL;
+	return 0;
+}
+
+void pcpu_freelist_destroy(struct pcpu_freelist *s)
+{
+	free_percpu(s->freelist);
+}
+
+static inline void pcpu_freelist_push_node(struct pcpu_freelist_head *head,
+					   struct pcpu_freelist_node *node)
+{
+	node->next = head->first;
+	WRITE_ONCE(head->first, node);
+}
+
+static inline void ___pcpu_freelist_push(struct pcpu_freelist_head *head,
+					 struct pcpu_freelist_node *node)
+{
+	raw_spin_lock(&head->lock);
+	pcpu_freelist_push_node(head, node);
+	raw_spin_unlock(&head->lock);
+}
+
+static inline bool pcpu_freelist_try_push_extra(struct pcpu_freelist *s,
+						struct pcpu_freelist_node *node)
+{
+	if (!raw_spin_trylock(&s->extralist.lock))
+		return false;
+
+	pcpu_freelist_push_node(&s->extralist, node);
+	raw_spin_unlock(&s->extralist.lock);
+	return true;
+}
+
+static inline void ___pcpu_freelist_push_nmi(struct pcpu_freelist *s,
+					     struct pcpu_freelist_node *node)
+{
+	int cpu, orig_cpu;
+
+	orig_cpu = raw_smp_processor_id();
+	while (1) {
+		for_each_cpu_wrap(cpu, cpu_possible_mask, orig_cpu) {
+			struct pcpu_freelist_head *head;
+
+			head = per_cpu_ptr(s->freelist, cpu);
+			if (raw_spin_trylock(&head->lock)) {
+				pcpu_freelist_push_node(head, node);
+				raw_spin_unlock(&head->lock);
+				return;
+			}
+		}
+
+		/* cannot lock any per cpu lock, try extralist */
+		if (pcpu_freelist_try_push_extra(s, node))
+			return;
+	}
+}
+
+void __pcpu_freelist_push(struct pcpu_freelist *s,
+			struct pcpu_freelist_node *node)
+{
+	if (in_nmi())
+		___pcpu_freelist_push_nmi(s, node);
+	else
+		___pcpu_freelist_push(this_cpu_ptr(s->freelist), node);
+}
+
+void pcpu_freelist_push(struct pcpu_freelist *s,
+			struct pcpu_freelist_node *node)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__pcpu_freelist_push(s, node);
+	local_irq_restore(flags);
+}
+
+void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
+			    u32 nr_elems)
+{
+	struct pcpu_freelist_head *head;
+	unsigned int cpu, cpu_idx, i, j, n, m;
+
+	n = nr_elems / num_possible_cpus();
+	m = nr_elems % num_possible_cpus();
+
+	cpu_idx = 0;
+	for_each_possible_cpu(cpu) {
+		head = per_cpu_ptr(s->freelist, cpu);
+		j = n + (cpu_idx < m ? 1 : 0);
+		for (i = 0; i < j; i++) {
+			/* No locking required as this is not visible yet. */
+			pcpu_freelist_push_node(head, buf);
+			buf += elem_size;
+		}
+		cpu_idx++;
+	}
+}
+
+static struct pcpu_freelist_node *___pcpu_freelist_pop(struct pcpu_freelist *s)
+{
+	struct pcpu_freelist_head *head;
+	struct pcpu_freelist_node *node;
+	int cpu;
+
+	for_each_cpu_wrap(cpu, cpu_possible_mask, raw_smp_processor_id()) {
+		head = per_cpu_ptr(s->freelist, cpu);
+		if (!READ_ONCE(head->first))
+			continue;
+		raw_spin_lock(&head->lock);
+		node = head->first;
+		if (node) {
+			WRITE_ONCE(head->first, node->next);
+			raw_spin_unlock(&head->lock);
+			return node;
+		}
+		raw_spin_unlock(&head->lock);
+	}
+
+	/* per cpu lists are all empty, try extralist */
+	if (!READ_ONCE(s->extralist.first))
+		return NULL;
+	raw_spin_lock(&s->extralist.lock);
+	node = s->extralist.first;
+	if (node)
+		WRITE_ONCE(s->extralist.first, node->next);
+	raw_spin_unlock(&s->extralist.lock);
+	return node;
+}
+
+static struct pcpu_freelist_node *
+___pcpu_freelist_pop_nmi(struct pcpu_freelist *s)
+{
+	struct pcpu_freelist_head *head;
+	struct pcpu_freelist_node *node;
+	int cpu;
+
+	for_each_cpu_wrap(cpu, cpu_possible_mask, raw_smp_processor_id()) {
+		head = per_cpu_ptr(s->freelist, cpu);
+		if (!READ_ONCE(head->first))
+			continue;
+		if (raw_spin_trylock(&head->lock)) {
+			node = head->first;
+			if (node) {
+				WRITE_ONCE(head->first, node->next);
+				raw_spin_unlock(&head->lock);
+				return node;
+			}
+			raw_spin_unlock(&head->lock);
+		}
+	}
+
+	/* cannot pop from per cpu lists, try extralist */
+	if (!READ_ONCE(s->extralist.first) || !raw_spin_trylock(&s->extralist.lock))
+		return NULL;
+	node = s->extralist.first;
+	if (node)
+		WRITE_ONCE(s->extralist.first, node->next);
+	raw_spin_unlock(&s->extralist.lock);
+	return node;
+}
+
+struct pcpu_freelist_node *__pcpu_freelist_pop(struct pcpu_freelist *s)
+{
+	if (in_nmi())
+		return ___pcpu_freelist_pop_nmi(s);
+	return ___pcpu_freelist_pop(s);
+}
+
+struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s)
+{
+	struct pcpu_freelist_node *ret;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	ret = __pcpu_freelist_pop(s);
+	local_irq_restore(flags);
+	return ret;
+}
diff --git a/kernel/bpf/percpu_freelist.h b/kernel/bpf/percpu_freelist.h
new file mode 100644
index 000000000..3c76553cf
--- /dev/null
+++ b/kernel/bpf/percpu_freelist.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (c) 2016 Facebook
+ */
+#ifndef __PERCPU_FREELIST_H__
+#define __PERCPU_FREELIST_H__
+#include <linux/spinlock.h>
+#include <linux/percpu.h>
+
+struct pcpu_freelist_head {
+	struct pcpu_freelist_node *first;
+	raw_spinlock_t lock;
+};
+
+struct pcpu_freelist {
+	struct pcpu_freelist_head __percpu *freelist;
+	struct pcpu_freelist_head extralist;
+};
+
+struct pcpu_freelist_node {
+	struct pcpu_freelist_node *next;
+};
+
+/* pcpu_freelist_* do spin_lock_irqsave. */
+void pcpu_freelist_push(struct pcpu_freelist *, struct pcpu_freelist_node *);
+struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *);
+/* __pcpu_freelist_* do spin_lock only. caller must disable irqs. */
+void __pcpu_freelist_push(struct pcpu_freelist *, struct pcpu_freelist_node *);
+struct pcpu_freelist_node *__pcpu_freelist_pop(struct pcpu_freelist *);
+void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
+			    u32 nr_elems);
+int pcpu_freelist_init(struct pcpu_freelist *);
+void pcpu_freelist_destroy(struct pcpu_freelist *s);
+#endif
diff --git a/kernel/bpf/preload/.gitignore b/kernel/bpf/preload/.gitignore
new file mode 100644
index 000000000..945232290
--- /dev/null
+++ b/kernel/bpf/preload/.gitignore
@@ -0,0 +1,2 @@
+/libbpf
+/bpf_preload_umd
diff --git a/kernel/bpf/preload/Kconfig b/kernel/bpf/preload/Kconfig
new file mode 100644
index 000000000..c9d45c9d6
--- /dev/null
+++ b/kernel/bpf/preload/Kconfig
@@ -0,0 +1,26 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config USERMODE_DRIVER
+	bool
+	default n
+
+menuconfig BPF_PRELOAD
+	bool "Preload BPF file system with kernel specific program and map iterators"
+	depends on BPF
+	depends on BPF_SYSCALL
+	# The dependency on !COMPILE_TEST prevents it from being enabled
+	# in allmodconfig or allyesconfig configurations
+	depends on !COMPILE_TEST
+	select USERMODE_DRIVER
+	help
+	  This builds kernel module with several embedded BPF programs that are
+	  pinned into BPF FS mount point as human readable files that are
+	  useful in debugging and introspection of BPF programs and maps.
+
+if BPF_PRELOAD
+config BPF_PRELOAD_UMD
+	tristate "bpf_preload kernel module"
+	default m
+	help
+	  This builds bpf_preload kernel module with embedded BPF programs for
+	  introspection in bpffs.
+endif
diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile
new file mode 100644
index 000000000..20f89cc0a
--- /dev/null
+++ b/kernel/bpf/preload/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+
+LIBBPF_INCLUDE = $(srctree)/tools/lib
+
+obj-$(CONFIG_BPF_PRELOAD_UMD) += bpf_preload.o
+CFLAGS_bpf_preload_kern.o += -I$(LIBBPF_INCLUDE)
+bpf_preload-objs += bpf_preload_kern.o
diff --git a/kernel/bpf/preload/bpf_preload.h b/kernel/bpf/preload/bpf_preload.h
new file mode 100644
index 000000000..f065c9121
--- /dev/null
+++ b/kernel/bpf/preload/bpf_preload.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BPF_PRELOAD_H
+#define _BPF_PRELOAD_H
+
+struct bpf_preload_info {
+	char link_name[16];
+	struct bpf_link *link;
+};
+
+struct bpf_preload_ops {
+	int (*preload)(struct bpf_preload_info *);
+	struct module *owner;
+};
+extern struct bpf_preload_ops *bpf_preload_ops;
+#define BPF_PRELOAD_LINKS 2
+#endif
diff --git a/kernel/bpf/preload/bpf_preload_kern.c b/kernel/bpf/preload/bpf_preload_kern.c
new file mode 100644
index 000000000..5106b5372
--- /dev/null
+++ b/kernel/bpf/preload/bpf_preload_kern.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/init.h>
+#include <linux/module.h>
+#include "bpf_preload.h"
+#include "iterators/iterators.lskel.h"
+
+static struct bpf_link *maps_link, *progs_link;
+static struct iterators_bpf *skel;
+
+static void free_links_and_skel(void)
+{
+	if (!IS_ERR_OR_NULL(maps_link))
+		bpf_link_put(maps_link);
+	if (!IS_ERR_OR_NULL(progs_link))
+		bpf_link_put(progs_link);
+	iterators_bpf__destroy(skel);
+}
+
+static int preload(struct bpf_preload_info *obj)
+{
+	strlcpy(obj[0].link_name, "maps.debug", sizeof(obj[0].link_name));
+	obj[0].link = maps_link;
+	strlcpy(obj[1].link_name, "progs.debug", sizeof(obj[1].link_name));
+	obj[1].link = progs_link;
+	return 0;
+}
+
+static struct bpf_preload_ops ops = {
+	.preload = preload,
+	.owner = THIS_MODULE,
+};
+
+static int load_skel(void)
+{
+	int err;
+
+	skel = iterators_bpf__open();
+	if (!skel)
+		return -ENOMEM;
+	err = iterators_bpf__load(skel);
+	if (err)
+		goto out;
+	err = iterators_bpf__attach(skel);
+	if (err)
+		goto out;
+	maps_link = bpf_link_get_from_fd(skel->links.dump_bpf_map_fd);
+	if (IS_ERR(maps_link)) {
+		err = PTR_ERR(maps_link);
+		goto out;
+	}
+	progs_link = bpf_link_get_from_fd(skel->links.dump_bpf_prog_fd);
+	if (IS_ERR(progs_link)) {
+		err = PTR_ERR(progs_link);
+		goto out;
+	}
+	/* Avoid taking over stdin/stdout/stderr of init process. Zeroing out
+	 * makes skel_closenz() a no-op later in iterators_bpf__destroy().
+	 */
+	close_fd(skel->links.dump_bpf_map_fd);
+	skel->links.dump_bpf_map_fd = 0;
+	close_fd(skel->links.dump_bpf_prog_fd);
+	skel->links.dump_bpf_prog_fd = 0;
+	return 0;
+out:
+	free_links_and_skel();
+	return err;
+}
+
+static int __init load(void)
+{
+	int err;
+
+	err = load_skel();
+	if (err)
+		return err;
+	bpf_preload_ops = &ops;
+	return err;
+}
+
+static void __exit fini(void)
+{
+	bpf_preload_ops = NULL;
+	free_links_and_skel();
+}
+late_initcall(load);
+module_exit(fini);
+MODULE_LICENSE("GPL");
diff --git a/kernel/bpf/preload/iterators/.gitignore b/kernel/bpf/preload/iterators/.gitignore
new file mode 100644
index 000000000..ffdb70230
--- /dev/null
+++ b/kernel/bpf/preload/iterators/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+/.output
diff --git a/kernel/bpf/preload/iterators/Makefile b/kernel/bpf/preload/iterators/Makefile
new file mode 100644
index 000000000..6762b1260
--- /dev/null
+++ b/kernel/bpf/preload/iterators/Makefile
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: GPL-2.0
+OUTPUT := .output
+abs_out := $(abspath $(OUTPUT))
+
+CLANG ?= clang
+LLC ?= llc
+LLVM_STRIP ?= llvm-strip
+
+TOOLS_PATH := $(abspath ../../../../tools)
+BPFTOOL_SRC := $(TOOLS_PATH)/bpf/bpftool
+BPFTOOL_OUTPUT := $(abs_out)/bpftool
+DEFAULT_BPFTOOL := $(BPFTOOL_OUTPUT)/bootstrap/bpftool
+BPFTOOL ?= $(DEFAULT_BPFTOOL)
+
+LIBBPF_SRC := $(TOOLS_PATH)/lib/bpf
+LIBBPF_OUTPUT := $(abs_out)/libbpf
+LIBBPF_DESTDIR := $(LIBBPF_OUTPUT)
+LIBBPF_INCLUDE := $(LIBBPF_DESTDIR)/include
+BPFOBJ := $(LIBBPF_OUTPUT)/libbpf.a
+
+INCLUDES := -I$(OUTPUT) -I$(LIBBPF_INCLUDE) -I$(TOOLS_PATH)/include/uapi
+CFLAGS := -g -Wall
+
+ifeq ($(V),1)
+Q =
+msg =
+else
+Q = @
+msg = @printf '  %-8s %s%s\n' "$(1)" "$(notdir $(2))" "$(if $(3), $(3))";
+MAKEFLAGS += --no-print-directory
+submake_extras := feature_display=0
+endif
+
+.DELETE_ON_ERROR:
+
+.PHONY: all clean
+
+all: iterators.lskel.h
+
+clean:
+	$(call msg,CLEAN)
+	$(Q)rm -rf $(OUTPUT) iterators
+
+iterators.lskel.h: $(OUTPUT)/iterators.bpf.o | $(BPFTOOL)
+	$(call msg,GEN-SKEL,$@)
+	$(Q)$(BPFTOOL) gen skeleton -L $< > $@
+
+
+$(OUTPUT)/iterators.bpf.o: iterators.bpf.c $(BPFOBJ) | $(OUTPUT)
+	$(call msg,BPF,$@)
+	$(Q)$(CLANG) -g -O2 -target bpf $(INCLUDES)			      \
+		 -c $(filter %.c,$^) -o $@ &&				      \
+	$(LLVM_STRIP) -g $@
+
+$(OUTPUT) $(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT):
+	$(call msg,MKDIR,$@)
+	$(Q)mkdir -p $@
+
+$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUTPUT)
+	$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC)			       \
+		    OUTPUT=$(abspath $(dir $@))/ prefix=		       \
+		    DESTDIR=$(LIBBPF_DESTDIR) $(abspath $@) install_headers
+
+$(DEFAULT_BPFTOOL): | $(BPFTOOL_OUTPUT)
+	$(Q)$(MAKE) $(submake_extras) -C $(BPFTOOL_SRC)	OUTPUT=$(BPFTOOL_OUTPUT)/ bootstrap
diff --git a/kernel/bpf/preload/iterators/README b/kernel/bpf/preload/iterators/README
new file mode 100644
index 000000000..7fd6d39a9
--- /dev/null
+++ b/kernel/bpf/preload/iterators/README
@@ -0,0 +1,4 @@
+WARNING:
+If you change "iterators.bpf.c" do "make -j" in this directory to rebuild "iterators.skel.h".
+Make sure to have clang 10 installed.
+See Documentation/bpf/bpf_devel_QA.rst
diff --git a/kernel/bpf/preload/iterators/iterators.bpf.c b/kernel/bpf/preload/iterators/iterators.bpf.c
new file mode 100644
index 000000000..03af86331
--- /dev/null
+++ b/kernel/bpf/preload/iterators/iterators.bpf.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+
+#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)
+struct seq_file;
+struct bpf_iter_meta {
+	struct seq_file *seq;
+	__u64 session_id;
+	__u64 seq_num;
+};
+
+struct bpf_map {
+	__u32 id;
+	char name[16];
+	__u32 max_entries;
+};
+
+struct bpf_iter__bpf_map {
+	struct bpf_iter_meta *meta;
+	struct bpf_map *map;
+};
+
+struct btf_type {
+	__u32 name_off;
+};
+
+struct btf_header {
+	__u32   str_len;
+};
+
+struct btf {
+	const char *strings;
+	struct btf_type **types;
+	struct btf_header hdr;
+};
+
+struct bpf_prog_aux {
+	__u32 id;
+	char name[16];
+	const char *attach_func_name;
+	struct bpf_prog *dst_prog;
+	struct bpf_func_info *func_info;
+	struct btf *btf;
+};
+
+struct bpf_prog {
+	struct bpf_prog_aux *aux;
+};
+
+struct bpf_iter__bpf_prog {
+	struct bpf_iter_meta *meta;
+	struct bpf_prog *prog;
+};
+#pragma clang attribute pop
+
+static const char *get_name(struct btf *btf, long btf_id, const char *fallback)
+{
+	struct btf_type **types, *t;
+	unsigned int name_off;
+	const char *str;
+
+	if (!btf)
+		return fallback;
+	str = btf->strings;
+	types = btf->types;
+	bpf_probe_read_kernel(&t, sizeof(t), types + btf_id);
+	name_off = BPF_CORE_READ(t, name_off);
+	if (name_off >= btf->hdr.str_len)
+		return fallback;
+	return str + name_off;
+}
+
+SEC("iter/bpf_map")
+int dump_bpf_map(struct bpf_iter__bpf_map *ctx)
+{
+	struct seq_file *seq = ctx->meta->seq;
+	__u64 seq_num = ctx->meta->seq_num;
+	struct bpf_map *map = ctx->map;
+
+	if (!map)
+		return 0;
+
+	if (seq_num == 0)
+		BPF_SEQ_PRINTF(seq, "  id name             max_entries\n");
+
+	BPF_SEQ_PRINTF(seq, "%4u %-16s%6d\n", map->id, map->name, map->max_entries);
+	return 0;
+}
+
+SEC("iter/bpf_prog")
+int dump_bpf_prog(struct bpf_iter__bpf_prog *ctx)
+{
+	struct seq_file *seq = ctx->meta->seq;
+	__u64 seq_num = ctx->meta->seq_num;
+	struct bpf_prog *prog = ctx->prog;
+	struct bpf_prog_aux *aux;
+
+	if (!prog)
+		return 0;
+
+	aux = prog->aux;
+	if (seq_num == 0)
+		BPF_SEQ_PRINTF(seq, "  id name             attached\n");
+
+	BPF_SEQ_PRINTF(seq, "%4u %-16s %s %s\n", aux->id,
+		       get_name(aux->btf, aux->func_info[0].type_id, aux->name),
+		       aux->attach_func_name, aux->dst_prog->aux->name);
+	return 0;
+}
+char LICENSE[] SEC("license") = "GPL";
diff --git a/kernel/bpf/preload/iterators/iterators.lskel.h b/kernel/bpf/preload/iterators/iterators.lskel.h
new file mode 100644
index 000000000..70f236a82
--- /dev/null
+++ b/kernel/bpf/preload/iterators/iterators.lskel.h
@@ -0,0 +1,425 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+/* THIS FILE IS AUTOGENERATED! */
+#ifndef __ITERATORS_BPF_SKEL_H__
+#define __ITERATORS_BPF_SKEL_H__
+
+#include <bpf/skel_internal.h>
+
+struct iterators_bpf {
+	struct bpf_loader_ctx ctx;
+	struct {
+		struct bpf_map_desc rodata;
+	} maps;
+	struct {
+		struct bpf_prog_desc dump_bpf_map;
+		struct bpf_prog_desc dump_bpf_prog;
+	} progs;
+	struct {
+		int dump_bpf_map_fd;
+		int dump_bpf_prog_fd;
+	} links;
+	struct iterators_bpf__rodata {
+	} *rodata;
+};
+
+static inline int
+iterators_bpf__dump_bpf_map__attach(struct iterators_bpf *skel)
+{
+	int prog_fd = skel->progs.dump_bpf_map.prog_fd;
+	int fd = skel_link_create(prog_fd, 0, BPF_TRACE_ITER);
+
+	if (fd > 0)
+		skel->links.dump_bpf_map_fd = fd;
+	return fd;
+}
+
+static inline int
+iterators_bpf__dump_bpf_prog__attach(struct iterators_bpf *skel)
+{
+	int prog_fd = skel->progs.dump_bpf_prog.prog_fd;
+	int fd = skel_link_create(prog_fd, 0, BPF_TRACE_ITER);
+
+	if (fd > 0)
+		skel->links.dump_bpf_prog_fd = fd;
+	return fd;
+}
+
+static inline int
+iterators_bpf__attach(struct iterators_bpf *skel)
+{
+	int ret = 0;
+
+	ret = ret < 0 ? ret : iterators_bpf__dump_bpf_map__attach(skel);
+	ret = ret < 0 ? ret : iterators_bpf__dump_bpf_prog__attach(skel);
+	return ret < 0 ? ret : 0;
+}
+
+static inline void
+iterators_bpf__detach(struct iterators_bpf *skel)
+{
+	skel_closenz(skel->links.dump_bpf_map_fd);
+	skel_closenz(skel->links.dump_bpf_prog_fd);
+}
+static void
+iterators_bpf__destroy(struct iterators_bpf *skel)
+{
+	if (!skel)
+		return;
+	iterators_bpf__detach(skel);
+	skel_closenz(skel->progs.dump_bpf_map.prog_fd);
+	skel_closenz(skel->progs.dump_bpf_prog.prog_fd);
+	skel_free_map_data(skel->rodata, skel->maps.rodata.initial_value, 4096);
+	skel_closenz(skel->maps.rodata.map_fd);
+	skel_free(skel);
+}
+static inline struct iterators_bpf *
+iterators_bpf__open(void)
+{
+	struct iterators_bpf *skel;
+
+	skel = skel_alloc(sizeof(*skel));
+	if (!skel)
+		goto cleanup;
+	skel->ctx.sz = (void *)&skel->links - (void *)skel;
+	skel->rodata = skel_prep_map_data((void *)"\
+\x20\x20\x69\x64\x20\x6e\x61\x6d\x65\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\
+\x20\x20\x20\x6d\x61\x78\x5f\x65\x6e\x74\x72\x69\x65\x73\x0a\0\x25\x34\x75\x20\
+\x25\x2d\x31\x36\x73\x25\x36\x64\x0a\0\x20\x20\x69\x64\x20\x6e\x61\x6d\x65\x20\
+\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x61\x74\x74\x61\x63\x68\x65\
+\x64\x0a\0\x25\x34\x75\x20\x25\x2d\x31\x36\x73\x20\x25\x73\x20\x25\x73\x0a\0", 4096, 98);
+	if (!skel->rodata)
+		goto cleanup;
+	skel->maps.rodata.initial_value = (__u64) (long) skel->rodata;
+	return skel;
+cleanup:
+	iterators_bpf__destroy(skel);
+	return NULL;
+}
+
+static inline int
+iterators_bpf__load(struct iterators_bpf *skel)
+{
+	struct bpf_load_and_run_opts opts = {};
+	int err;
+
+	opts.ctx = (struct bpf_loader_ctx *)skel;
+	opts.data_sz = 6056;
+	opts.data = (void *)"\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x9f\xeb\x01\0\
+\x18\0\0\0\0\0\0\0\x1c\x04\0\0\x1c\x04\0\0\xf9\x04\0\0\0\0\0\0\0\0\0\x02\x02\0\
+\0\0\x01\0\0\0\x02\0\0\x04\x10\0\0\0\x13\0\0\0\x03\0\0\0\0\0\0\0\x18\0\0\0\x04\
+\0\0\0\x40\0\0\0\0\0\0\0\0\0\0\x02\x08\0\0\0\0\0\0\0\0\0\0\x02\x0d\0\0\0\0\0\0\
+\0\x01\0\0\x0d\x06\0\0\0\x1c\0\0\0\x01\0\0\0\x20\0\0\0\0\0\0\x01\x04\0\0\0\x20\
+\0\0\x01\x24\0\0\0\x01\0\0\x0c\x05\0\0\0\xa3\0\0\0\x03\0\0\x04\x18\0\0\0\xb1\0\
+\0\0\x09\0\0\0\0\0\0\0\xb5\0\0\0\x0b\0\0\0\x40\0\0\0\xc0\0\0\0\x0b\0\0\0\x80\0\
+\0\0\0\0\0\0\0\0\0\x02\x0a\0\0\0\xc8\0\0\0\0\0\0\x07\0\0\0\0\xd1\0\0\0\0\0\0\
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+	opts.insns_sz = 2216;
+	opts.insns = (void *)"\
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+\x18\x12\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x08\x17\0\0\x7b\x01\0\0\0\0\0\0\x18\
+\x60\0\0\0\0\0\0\0\0\0\0\x28\x14\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x50\x17\0\0\
+\x7b\x01\0\0\0\0\0\0\x18\x60\0\0\0\0\0\0\0\0\0\0\x30\x14\0\0\x18\x61\0\0\0\0\0\
+\0\0\0\0\0\x60\x17\0\0\x7b\x01\0\0\0\0\0\0\x18\x60\0\0\0\0\0\0\0\0\0\0\xd0\x15\
+\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x80\x17\0\0\x7b\x01\0\0\0\0\0\0\x18\x60\0\0\0\
+\0\0\0\0\0\0\0\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x78\x17\0\0\x7b\x01\0\0\0\0\
+\0\0\x61\x60\x08\0\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x18\x17\0\0\x63\x01\0\0\
+\0\0\0\0\x61\x60\x0c\0\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x1c\x17\0\0\x63\x01\
+\0\0\0\0\0\0\x79\x60\x10\0\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x20\x17\0\0\x7b\
+\x01\0\0\0\0\0\0\x61\xa0\x78\xff\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x48\x17\0\
+\0\x63\x01\0\0\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x90\x17\0\0\xb7\x02\0\0\x12\
+\0\0\0\xb7\x03\0\0\x0c\0\0\0\xb7\x04\0\0\0\0\0\0\x85\0\0\0\xa7\0\0\0\xbf\x07\0\
+\0\0\0\0\0\xc5\x07\x13\xff\0\0\0\0\x18\x60\0\0\0\0\0\0\0\0\0\0\0\x17\0\0\x63\
+\x70\x6c\0\0\0\0\0\x77\x07\0\0\x20\0\0\0\x63\x70\x70\0\0\0\0\0\xb7\x01\0\0\x05\
+\0\0\0\x18\x62\0\0\0\0\0\0\0\0\0\0\0\x17\0\0\xb7\x03\0\0\x8c\0\0\0\x85\0\0\0\
+\xa6\0\0\0\xbf\x07\0\0\0\0\0\0\x18\x60\0\0\0\0\0\0\0\0\0\0\x70\x17\0\0\x61\x01\
+\0\0\0\0\0\0\xd5\x01\x02\0\0\0\0\0\xbf\x19\0\0\0\0\0\0\x85\0\0\0\xa8\0\0\0\xc5\
+\x07\x01\xff\0\0\0\0\x63\x7a\x84\xff\0\0\0\0\x61\xa1\x78\xff\0\0\0\0\xd5\x01\
+\x02\0\0\0\0\0\xbf\x19\0\0\0\0\0\0\x85\0\0\0\xa8\0\0\0\x61\xa0\x80\xff\0\0\0\0\
+\x63\x06\x28\0\0\0\0\0\x61\xa0\x84\xff\0\0\0\0\x63\x06\x2c\0\0\0\0\0\x18\x61\0\
+\0\0\0\0\0\0\0\0\0\0\0\0\0\x61\x10\0\0\0\0\0\0\x63\x06\x18\0\0\0\0\0\xb7\0\0\0\
+\0\0\0\0\x95\0\0\0\0\0\0\0";
+	err = bpf_load_and_run(&opts);
+	if (err < 0)
+		return err;
+	skel->rodata = skel_finalize_map_data(&skel->maps.rodata.initial_value,
+					4096, PROT_READ, skel->maps.rodata.map_fd);
+	if (!skel->rodata)
+		return -ENOMEM;
+	return 0;
+}
+
+static inline struct iterators_bpf *
+iterators_bpf__open_and_load(void)
+{
+	struct iterators_bpf *skel;
+
+	skel = iterators_bpf__open();
+	if (!skel)
+		return NULL;
+	if (iterators_bpf__load(skel)) {
+		iterators_bpf__destroy(skel);
+		return NULL;
+	}
+	return skel;
+}
+
+#endif /* __ITERATORS_BPF_SKEL_H__ */
diff --git a/kernel/bpf/prog_iter.c b/kernel/bpf/prog_iter.c
new file mode 100644
index 000000000..53a73c841
--- /dev/null
+++ b/kernel/bpf/prog_iter.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2020 Facebook */
+#include <linux/bpf.h>
+#include <linux/fs.h>
+#include <linux/filter.h>
+#include <linux/kernel.h>
+#include <linux/btf_ids.h>
+
+struct bpf_iter_seq_prog_info {
+	u32 prog_id;
+};
+
+static void *bpf_prog_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct bpf_iter_seq_prog_info *info = seq->private;
+	struct bpf_prog *prog;
+
+	prog = bpf_prog_get_curr_or_next(&info->prog_id);
+	if (!prog)
+		return NULL;
+
+	if (*pos == 0)
+		++*pos;
+	return prog;
+}
+
+static void *bpf_prog_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct bpf_iter_seq_prog_info *info = seq->private;
+
+	++*pos;
+	++info->prog_id;
+	bpf_prog_put((struct bpf_prog *)v);
+	return bpf_prog_get_curr_or_next(&info->prog_id);
+}
+
+struct bpf_iter__bpf_prog {
+	__bpf_md_ptr(struct bpf_iter_meta *, meta);
+	__bpf_md_ptr(struct bpf_prog *, prog);
+};
+
+DEFINE_BPF_ITER_FUNC(bpf_prog, struct bpf_iter_meta *meta, struct bpf_prog *prog)
+
+static int __bpf_prog_seq_show(struct seq_file *seq, void *v, bool in_stop)
+{
+	struct bpf_iter__bpf_prog ctx;
+	struct bpf_iter_meta meta;
+	struct bpf_prog *prog;
+	int ret = 0;
+
+	ctx.meta = &meta;
+	ctx.prog = v;
+	meta.seq = seq;
+	prog = bpf_iter_get_info(&meta, in_stop);
+	if (prog)
+		ret = bpf_iter_run_prog(prog, &ctx);
+
+	return ret;
+}
+
+static int bpf_prog_seq_show(struct seq_file *seq, void *v)
+{
+	return __bpf_prog_seq_show(seq, v, false);
+}
+
+static void bpf_prog_seq_stop(struct seq_file *seq, void *v)
+{
+	if (!v)
+		(void)__bpf_prog_seq_show(seq, v, true);
+	else
+		bpf_prog_put((struct bpf_prog *)v);
+}
+
+static const struct seq_operations bpf_prog_seq_ops = {
+	.start	= bpf_prog_seq_start,
+	.next	= bpf_prog_seq_next,
+	.stop	= bpf_prog_seq_stop,
+	.show	= bpf_prog_seq_show,
+};
+
+BTF_ID_LIST(btf_bpf_prog_id)
+BTF_ID(struct, bpf_prog)
+
+static const struct bpf_iter_seq_info bpf_prog_seq_info = {
+	.seq_ops		= &bpf_prog_seq_ops,
+	.init_seq_private	= NULL,
+	.fini_seq_private	= NULL,
+	.seq_priv_size		= sizeof(struct bpf_iter_seq_prog_info),
+};
+
+static struct bpf_iter_reg bpf_prog_reg_info = {
+	.target			= "bpf_prog",
+	.ctx_arg_info_size	= 1,
+	.ctx_arg_info		= {
+		{ offsetof(struct bpf_iter__bpf_prog, prog),
+		  PTR_TO_BTF_ID_OR_NULL },
+	},
+	.seq_info		= &bpf_prog_seq_info,
+};
+
+static int __init bpf_prog_iter_init(void)
+{
+	bpf_prog_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_prog_id;
+	return bpf_iter_reg_target(&bpf_prog_reg_info);
+}
+
+late_initcall(bpf_prog_iter_init);
diff --git a/kernel/bpf/queue_stack_maps.c b/kernel/bpf/queue_stack_maps.c
new file mode 100644
index 000000000..a8fe64031
--- /dev/null
+++ b/kernel/bpf/queue_stack_maps.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * queue_stack_maps.c: BPF queue and stack maps
+ *
+ * Copyright (c) 2018 Politecnico di Torino
+ */
+#include <linux/bpf.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/capability.h>
+#include <linux/btf_ids.h>
+#include "percpu_freelist.h"
+
+#define QUEUE_STACK_CREATE_FLAG_MASK \
+	(BPF_F_NUMA_NODE | BPF_F_ACCESS_MASK)
+
+struct bpf_queue_stack {
+	struct bpf_map map;
+	raw_spinlock_t lock;
+	u32 head, tail;
+	u32 size; /* max_entries + 1 */
+
+	char elements[] __aligned(8);
+};
+
+static struct bpf_queue_stack *bpf_queue_stack(struct bpf_map *map)
+{
+	return container_of(map, struct bpf_queue_stack, map);
+}
+
+static bool queue_stack_map_is_empty(struct bpf_queue_stack *qs)
+{
+	return qs->head == qs->tail;
+}
+
+static bool queue_stack_map_is_full(struct bpf_queue_stack *qs)
+{
+	u32 head = qs->head + 1;
+
+	if (unlikely(head >= qs->size))
+		head = 0;
+
+	return head == qs->tail;
+}
+
+/* Called from syscall */
+static int queue_stack_map_alloc_check(union bpf_attr *attr)
+{
+	if (!bpf_capable())
+		return -EPERM;
+
+	/* check sanity of attributes */
+	if (attr->max_entries == 0 || attr->key_size != 0 ||
+	    attr->value_size == 0 ||
+	    attr->map_flags & ~QUEUE_STACK_CREATE_FLAG_MASK ||
+	    !bpf_map_flags_access_ok(attr->map_flags))
+		return -EINVAL;
+
+	if (attr->value_size > KMALLOC_MAX_SIZE)
+		/* if value_size is bigger, the user space won't be able to
+		 * access the elements.
+		 */
+		return -E2BIG;
+
+	return 0;
+}
+
+static struct bpf_map *queue_stack_map_alloc(union bpf_attr *attr)
+{
+	int numa_node = bpf_map_attr_numa_node(attr);
+	struct bpf_queue_stack *qs;
+	u64 size, queue_size;
+
+	size = (u64) attr->max_entries + 1;
+	queue_size = sizeof(*qs) + size * attr->value_size;
+
+	qs = bpf_map_area_alloc(queue_size, numa_node);
+	if (!qs)
+		return ERR_PTR(-ENOMEM);
+
+	bpf_map_init_from_attr(&qs->map, attr);
+
+	qs->size = size;
+
+	raw_spin_lock_init(&qs->lock);
+
+	return &qs->map;
+}
+
+/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
+static void queue_stack_map_free(struct bpf_map *map)
+{
+	struct bpf_queue_stack *qs = bpf_queue_stack(map);
+
+	bpf_map_area_free(qs);
+}
+
+static int __queue_map_get(struct bpf_map *map, void *value, bool delete)
+{
+	struct bpf_queue_stack *qs = bpf_queue_stack(map);
+	unsigned long flags;
+	int err = 0;
+	void *ptr;
+
+	if (in_nmi()) {
+		if (!raw_spin_trylock_irqsave(&qs->lock, flags))
+			return -EBUSY;
+	} else {
+		raw_spin_lock_irqsave(&qs->lock, flags);
+	}
+
+	if (queue_stack_map_is_empty(qs)) {
+		memset(value, 0, qs->map.value_size);
+		err = -ENOENT;
+		goto out;
+	}
+
+	ptr = &qs->elements[qs->tail * qs->map.value_size];
+	memcpy(value, ptr, qs->map.value_size);
+
+	if (delete) {
+		if (unlikely(++qs->tail >= qs->size))
+			qs->tail = 0;
+	}
+
+out:
+	raw_spin_unlock_irqrestore(&qs->lock, flags);
+	return err;
+}
+
+
+static int __stack_map_get(struct bpf_map *map, void *value, bool delete)
+{
+	struct bpf_queue_stack *qs = bpf_queue_stack(map);
+	unsigned long flags;
+	int err = 0;
+	void *ptr;
+	u32 index;
+
+	if (in_nmi()) {
+		if (!raw_spin_trylock_irqsave(&qs->lock, flags))
+			return -EBUSY;
+	} else {
+		raw_spin_lock_irqsave(&qs->lock, flags);
+	}
+
+	if (queue_stack_map_is_empty(qs)) {
+		memset(value, 0, qs->map.value_size);
+		err = -ENOENT;
+		goto out;
+	}
+
+	index = qs->head - 1;
+	if (unlikely(index >= qs->size))
+		index = qs->size - 1;
+
+	ptr = &qs->elements[index * qs->map.value_size];
+	memcpy(value, ptr, qs->map.value_size);
+
+	if (delete)
+		qs->head = index;
+
+out:
+	raw_spin_unlock_irqrestore(&qs->lock, flags);
+	return err;
+}
+
+/* Called from syscall or from eBPF program */
+static int queue_map_peek_elem(struct bpf_map *map, void *value)
+{
+	return __queue_map_get(map, value, false);
+}
+
+/* Called from syscall or from eBPF program */
+static int stack_map_peek_elem(struct bpf_map *map, void *value)
+{
+	return __stack_map_get(map, value, false);
+}
+
+/* Called from syscall or from eBPF program */
+static int queue_map_pop_elem(struct bpf_map *map, void *value)
+{
+	return __queue_map_get(map, value, true);
+}
+
+/* Called from syscall or from eBPF program */
+static int stack_map_pop_elem(struct bpf_map *map, void *value)
+{
+	return __stack_map_get(map, value, true);
+}
+
+/* Called from syscall or from eBPF program */
+static int queue_stack_map_push_elem(struct bpf_map *map, void *value,
+				     u64 flags)
+{
+	struct bpf_queue_stack *qs = bpf_queue_stack(map);
+	unsigned long irq_flags;
+	int err = 0;
+	void *dst;
+
+	/* BPF_EXIST is used to force making room for a new element in case the
+	 * map is full
+	 */
+	bool replace = (flags & BPF_EXIST);
+
+	/* Check supported flags for queue and stack maps */
+	if (flags & BPF_NOEXIST || flags > BPF_EXIST)
+		return -EINVAL;
+
+	if (in_nmi()) {
+		if (!raw_spin_trylock_irqsave(&qs->lock, irq_flags))
+			return -EBUSY;
+	} else {
+		raw_spin_lock_irqsave(&qs->lock, irq_flags);
+	}
+
+	if (queue_stack_map_is_full(qs)) {
+		if (!replace) {
+			err = -E2BIG;
+			goto out;
+		}
+		/* advance tail pointer to overwrite oldest element */
+		if (unlikely(++qs->tail >= qs->size))
+			qs->tail = 0;
+	}
+
+	dst = &qs->elements[qs->head * qs->map.value_size];
+	memcpy(dst, value, qs->map.value_size);
+
+	if (unlikely(++qs->head >= qs->size))
+		qs->head = 0;
+
+out:
+	raw_spin_unlock_irqrestore(&qs->lock, irq_flags);
+	return err;
+}
+
+/* Called from syscall or from eBPF program */
+static void *queue_stack_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	return NULL;
+}
+
+/* Called from syscall or from eBPF program */
+static int queue_stack_map_update_elem(struct bpf_map *map, void *key,
+				       void *value, u64 flags)
+{
+	return -EINVAL;
+}
+
+/* Called from syscall or from eBPF program */
+static int queue_stack_map_delete_elem(struct bpf_map *map, void *key)
+{
+	return -EINVAL;
+}
+
+/* Called from syscall */
+static int queue_stack_map_get_next_key(struct bpf_map *map, void *key,
+					void *next_key)
+{
+	return -EINVAL;
+}
+
+BTF_ID_LIST_SINGLE(queue_map_btf_ids, struct, bpf_queue_stack)
+const struct bpf_map_ops queue_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = queue_stack_map_alloc_check,
+	.map_alloc = queue_stack_map_alloc,
+	.map_free = queue_stack_map_free,
+	.map_lookup_elem = queue_stack_map_lookup_elem,
+	.map_update_elem = queue_stack_map_update_elem,
+	.map_delete_elem = queue_stack_map_delete_elem,
+	.map_push_elem = queue_stack_map_push_elem,
+	.map_pop_elem = queue_map_pop_elem,
+	.map_peek_elem = queue_map_peek_elem,
+	.map_get_next_key = queue_stack_map_get_next_key,
+	.map_btf_id = &queue_map_btf_ids[0],
+};
+
+const struct bpf_map_ops stack_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = queue_stack_map_alloc_check,
+	.map_alloc = queue_stack_map_alloc,
+	.map_free = queue_stack_map_free,
+	.map_lookup_elem = queue_stack_map_lookup_elem,
+	.map_update_elem = queue_stack_map_update_elem,
+	.map_delete_elem = queue_stack_map_delete_elem,
+	.map_push_elem = queue_stack_map_push_elem,
+	.map_pop_elem = stack_map_pop_elem,
+	.map_peek_elem = stack_map_peek_elem,
+	.map_get_next_key = queue_stack_map_get_next_key,
+	.map_btf_id = &queue_map_btf_ids[0],
+};
diff --git a/kernel/bpf/reuseport_array.c b/kernel/bpf/reuseport_array.c
new file mode 100644
index 000000000..82c61612f
--- /dev/null
+++ b/kernel/bpf/reuseport_array.c
@@ -0,0 +1,348 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018 Facebook
+ */
+#include <linux/bpf.h>
+#include <linux/err.h>
+#include <linux/sock_diag.h>
+#include <net/sock_reuseport.h>
+#include <linux/btf_ids.h>
+
+struct reuseport_array {
+	struct bpf_map map;
+	struct sock __rcu *ptrs[];
+};
+
+static struct reuseport_array *reuseport_array(struct bpf_map *map)
+{
+	return (struct reuseport_array *)map;
+}
+
+/* The caller must hold the reuseport_lock */
+void bpf_sk_reuseport_detach(struct sock *sk)
+{
+	struct sock __rcu **socks;
+
+	write_lock_bh(&sk->sk_callback_lock);
+	socks = __locked_read_sk_user_data_with_flags(sk, SK_USER_DATA_BPF);
+	if (socks) {
+		WRITE_ONCE(sk->sk_user_data, NULL);
+		/*
+		 * Do not move this NULL assignment outside of
+		 * sk->sk_callback_lock because there is
+		 * a race with reuseport_array_free()
+		 * which does not hold the reuseport_lock.
+		 */
+		RCU_INIT_POINTER(*socks, NULL);
+	}
+	write_unlock_bh(&sk->sk_callback_lock);
+}
+
+static int reuseport_array_alloc_check(union bpf_attr *attr)
+{
+	if (attr->value_size != sizeof(u32) &&
+	    attr->value_size != sizeof(u64))
+		return -EINVAL;
+
+	return array_map_alloc_check(attr);
+}
+
+static void *reuseport_array_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct reuseport_array *array = reuseport_array(map);
+	u32 index = *(u32 *)key;
+
+	if (unlikely(index >= array->map.max_entries))
+		return NULL;
+
+	return rcu_dereference(array->ptrs[index]);
+}
+
+/* Called from syscall only */
+static int reuseport_array_delete_elem(struct bpf_map *map, void *key)
+{
+	struct reuseport_array *array = reuseport_array(map);
+	u32 index = *(u32 *)key;
+	struct sock *sk;
+	int err;
+
+	if (index >= map->max_entries)
+		return -E2BIG;
+
+	if (!rcu_access_pointer(array->ptrs[index]))
+		return -ENOENT;
+
+	spin_lock_bh(&reuseport_lock);
+
+	sk = rcu_dereference_protected(array->ptrs[index],
+				       lockdep_is_held(&reuseport_lock));
+	if (sk) {
+		write_lock_bh(&sk->sk_callback_lock);
+		WRITE_ONCE(sk->sk_user_data, NULL);
+		RCU_INIT_POINTER(array->ptrs[index], NULL);
+		write_unlock_bh(&sk->sk_callback_lock);
+		err = 0;
+	} else {
+		err = -ENOENT;
+	}
+
+	spin_unlock_bh(&reuseport_lock);
+
+	return err;
+}
+
+static void reuseport_array_free(struct bpf_map *map)
+{
+	struct reuseport_array *array = reuseport_array(map);
+	struct sock *sk;
+	u32 i;
+
+	/*
+	 * ops->map_*_elem() will not be able to access this
+	 * array now. Hence, this function only races with
+	 * bpf_sk_reuseport_detach() which was triggered by
+	 * close() or disconnect().
+	 *
+	 * This function and bpf_sk_reuseport_detach() are
+	 * both removing sk from "array".  Who removes it
+	 * first does not matter.
+	 *
+	 * The only concern here is bpf_sk_reuseport_detach()
+	 * may access "array" which is being freed here.
+	 * bpf_sk_reuseport_detach() access this "array"
+	 * through sk->sk_user_data _and_ with sk->sk_callback_lock
+	 * held which is enough because this "array" is not freed
+	 * until all sk->sk_user_data has stopped referencing this "array".
+	 *
+	 * Hence, due to the above, taking "reuseport_lock" is not
+	 * needed here.
+	 */
+
+	/*
+	 * Since reuseport_lock is not taken, sk is accessed under
+	 * rcu_read_lock()
+	 */
+	rcu_read_lock();
+	for (i = 0; i < map->max_entries; i++) {
+		sk = rcu_dereference(array->ptrs[i]);
+		if (sk) {
+			write_lock_bh(&sk->sk_callback_lock);
+			/*
+			 * No need for WRITE_ONCE(). At this point,
+			 * no one is reading it without taking the
+			 * sk->sk_callback_lock.
+			 */
+			sk->sk_user_data = NULL;
+			write_unlock_bh(&sk->sk_callback_lock);
+			RCU_INIT_POINTER(array->ptrs[i], NULL);
+		}
+	}
+	rcu_read_unlock();
+
+	/*
+	 * Once reaching here, all sk->sk_user_data is not
+	 * referencing this "array". "array" can be freed now.
+	 */
+	bpf_map_area_free(array);
+}
+
+static struct bpf_map *reuseport_array_alloc(union bpf_attr *attr)
+{
+	int numa_node = bpf_map_attr_numa_node(attr);
+	struct reuseport_array *array;
+
+	if (!bpf_capable())
+		return ERR_PTR(-EPERM);
+
+	/* allocate all map elements and zero-initialize them */
+	array = bpf_map_area_alloc(struct_size(array, ptrs, attr->max_entries), numa_node);
+	if (!array)
+		return ERR_PTR(-ENOMEM);
+
+	/* copy mandatory map attributes */
+	bpf_map_init_from_attr(&array->map, attr);
+
+	return &array->map;
+}
+
+int bpf_fd_reuseport_array_lookup_elem(struct bpf_map *map, void *key,
+				       void *value)
+{
+	struct sock *sk;
+	int err;
+
+	if (map->value_size != sizeof(u64))
+		return -ENOSPC;
+
+	rcu_read_lock();
+	sk = reuseport_array_lookup_elem(map, key);
+	if (sk) {
+		*(u64 *)value = __sock_gen_cookie(sk);
+		err = 0;
+	} else {
+		err = -ENOENT;
+	}
+	rcu_read_unlock();
+
+	return err;
+}
+
+static int
+reuseport_array_update_check(const struct reuseport_array *array,
+			     const struct sock *nsk,
+			     const struct sock *osk,
+			     const struct sock_reuseport *nsk_reuse,
+			     u32 map_flags)
+{
+	if (osk && map_flags == BPF_NOEXIST)
+		return -EEXIST;
+
+	if (!osk && map_flags == BPF_EXIST)
+		return -ENOENT;
+
+	if (nsk->sk_protocol != IPPROTO_UDP && nsk->sk_protocol != IPPROTO_TCP)
+		return -ENOTSUPP;
+
+	if (nsk->sk_family != AF_INET && nsk->sk_family != AF_INET6)
+		return -ENOTSUPP;
+
+	if (nsk->sk_type != SOCK_STREAM && nsk->sk_type != SOCK_DGRAM)
+		return -ENOTSUPP;
+
+	/*
+	 * sk must be hashed (i.e. listening in the TCP case or binded
+	 * in the UDP case) and
+	 * it must also be a SO_REUSEPORT sk (i.e. reuse cannot be NULL).
+	 *
+	 * Also, sk will be used in bpf helper that is protected by
+	 * rcu_read_lock().
+	 */
+	if (!sock_flag(nsk, SOCK_RCU_FREE) || !sk_hashed(nsk) || !nsk_reuse)
+		return -EINVAL;
+
+	/* READ_ONCE because the sk->sk_callback_lock may not be held here */
+	if (READ_ONCE(nsk->sk_user_data))
+		return -EBUSY;
+
+	return 0;
+}
+
+/*
+ * Called from syscall only.
+ * The "nsk" in the fd refcnt.
+ * The "osk" and "reuse" are protected by reuseport_lock.
+ */
+int bpf_fd_reuseport_array_update_elem(struct bpf_map *map, void *key,
+				       void *value, u64 map_flags)
+{
+	struct reuseport_array *array = reuseport_array(map);
+	struct sock *free_osk = NULL, *osk, *nsk;
+	struct sock_reuseport *reuse;
+	u32 index = *(u32 *)key;
+	uintptr_t sk_user_data;
+	struct socket *socket;
+	int err, fd;
+
+	if (map_flags > BPF_EXIST)
+		return -EINVAL;
+
+	if (index >= map->max_entries)
+		return -E2BIG;
+
+	if (map->value_size == sizeof(u64)) {
+		u64 fd64 = *(u64 *)value;
+
+		if (fd64 > S32_MAX)
+			return -EINVAL;
+		fd = fd64;
+	} else {
+		fd = *(int *)value;
+	}
+
+	socket = sockfd_lookup(fd, &err);
+	if (!socket)
+		return err;
+
+	nsk = socket->sk;
+	if (!nsk) {
+		err = -EINVAL;
+		goto put_file;
+	}
+
+	/* Quick checks before taking reuseport_lock */
+	err = reuseport_array_update_check(array, nsk,
+					   rcu_access_pointer(array->ptrs[index]),
+					   rcu_access_pointer(nsk->sk_reuseport_cb),
+					   map_flags);
+	if (err)
+		goto put_file;
+
+	spin_lock_bh(&reuseport_lock);
+	/*
+	 * Some of the checks only need reuseport_lock
+	 * but it is done under sk_callback_lock also
+	 * for simplicity reason.
+	 */
+	write_lock_bh(&nsk->sk_callback_lock);
+
+	osk = rcu_dereference_protected(array->ptrs[index],
+					lockdep_is_held(&reuseport_lock));
+	reuse = rcu_dereference_protected(nsk->sk_reuseport_cb,
+					  lockdep_is_held(&reuseport_lock));
+	err = reuseport_array_update_check(array, nsk, osk, reuse, map_flags);
+	if (err)
+		goto put_file_unlock;
+
+	sk_user_data = (uintptr_t)&array->ptrs[index] | SK_USER_DATA_NOCOPY |
+		SK_USER_DATA_BPF;
+	WRITE_ONCE(nsk->sk_user_data, (void *)sk_user_data);
+	rcu_assign_pointer(array->ptrs[index], nsk);
+	free_osk = osk;
+	err = 0;
+
+put_file_unlock:
+	write_unlock_bh(&nsk->sk_callback_lock);
+
+	if (free_osk) {
+		write_lock_bh(&free_osk->sk_callback_lock);
+		WRITE_ONCE(free_osk->sk_user_data, NULL);
+		write_unlock_bh(&free_osk->sk_callback_lock);
+	}
+
+	spin_unlock_bh(&reuseport_lock);
+put_file:
+	fput(socket->file);
+	return err;
+}
+
+/* Called from syscall */
+static int reuseport_array_get_next_key(struct bpf_map *map, void *key,
+					void *next_key)
+{
+	struct reuseport_array *array = reuseport_array(map);
+	u32 index = key ? *(u32 *)key : U32_MAX;
+	u32 *next = (u32 *)next_key;
+
+	if (index >= array->map.max_entries) {
+		*next = 0;
+		return 0;
+	}
+
+	if (index == array->map.max_entries - 1)
+		return -ENOENT;
+
+	*next = index + 1;
+	return 0;
+}
+
+BTF_ID_LIST_SINGLE(reuseport_array_map_btf_ids, struct, reuseport_array)
+const struct bpf_map_ops reuseport_array_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc_check = reuseport_array_alloc_check,
+	.map_alloc = reuseport_array_alloc,
+	.map_free = reuseport_array_free,
+	.map_lookup_elem = reuseport_array_lookup_elem,
+	.map_get_next_key = reuseport_array_get_next_key,
+	.map_delete_elem = reuseport_array_delete_elem,
+	.map_btf_id = &reuseport_array_map_btf_ids[0],
+};
diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c
new file mode 100644
index 000000000..9e832acf4
--- /dev/null
+++ b/kernel/bpf/ringbuf.c
@@ -0,0 +1,776 @@
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/err.h>
+#include <linux/irq_work.h>
+#include <linux/slab.h>
+#include <linux/filter.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/wait.h>
+#include <linux/poll.h>
+#include <linux/kmemleak.h>
+#include <uapi/linux/btf.h>
+#include <linux/btf_ids.h>
+
+#define RINGBUF_CREATE_FLAG_MASK (BPF_F_NUMA_NODE)
+
+/* non-mmap()'able part of bpf_ringbuf (everything up to consumer page) */
+#define RINGBUF_PGOFF \
+	(offsetof(struct bpf_ringbuf, consumer_pos) >> PAGE_SHIFT)
+/* consumer page and producer page */
+#define RINGBUF_POS_PAGES 2
+
+#define RINGBUF_MAX_RECORD_SZ (UINT_MAX/4)
+
+/* Maximum size of ring buffer area is limited by 32-bit page offset within
+ * record header, counted in pages. Reserve 8 bits for extensibility, and take
+ * into account few extra pages for consumer/producer pages and
+ * non-mmap()'able parts. This gives 64GB limit, which seems plenty for single
+ * ring buffer.
+ */
+#define RINGBUF_MAX_DATA_SZ \
+	(((1ULL << 24) - RINGBUF_POS_PAGES - RINGBUF_PGOFF) * PAGE_SIZE)
+
+struct bpf_ringbuf {
+	wait_queue_head_t waitq;
+	struct irq_work work;
+	u64 mask;
+	struct page **pages;
+	int nr_pages;
+	spinlock_t spinlock ____cacheline_aligned_in_smp;
+	/* For user-space producer ring buffers, an atomic_t busy bit is used
+	 * to synchronize access to the ring buffers in the kernel, rather than
+	 * the spinlock that is used for kernel-producer ring buffers. This is
+	 * done because the ring buffer must hold a lock across a BPF program's
+	 * callback:
+	 *
+	 *    __bpf_user_ringbuf_peek() // lock acquired
+	 * -> program callback_fn()
+	 * -> __bpf_user_ringbuf_sample_release() // lock released
+	 *
+	 * It is unsafe and incorrect to hold an IRQ spinlock across what could
+	 * be a long execution window, so we instead simply disallow concurrent
+	 * access to the ring buffer by kernel consumers, and return -EBUSY from
+	 * __bpf_user_ringbuf_peek() if the busy bit is held by another task.
+	 */
+	atomic_t busy ____cacheline_aligned_in_smp;
+	/* Consumer and producer counters are put into separate pages to
+	 * allow each position to be mapped with different permissions.
+	 * This prevents a user-space application from modifying the
+	 * position and ruining in-kernel tracking. The permissions of the
+	 * pages depend on who is producing samples: user-space or the
+	 * kernel.
+	 *
+	 * Kernel-producer
+	 * ---------------
+	 * The producer position and data pages are mapped as r/o in
+	 * userspace. For this approach, bits in the header of samples are
+	 * used to signal to user-space, and to other producers, whether a
+	 * sample is currently being written.
+	 *
+	 * User-space producer
+	 * -------------------
+	 * Only the page containing the consumer position is mapped r/o in
+	 * user-space. User-space producers also use bits of the header to
+	 * communicate to the kernel, but the kernel must carefully check and
+	 * validate each sample to ensure that they're correctly formatted, and
+	 * fully contained within the ring buffer.
+	 */
+	unsigned long consumer_pos __aligned(PAGE_SIZE);
+	unsigned long producer_pos __aligned(PAGE_SIZE);
+	char data[] __aligned(PAGE_SIZE);
+};
+
+struct bpf_ringbuf_map {
+	struct bpf_map map;
+	struct bpf_ringbuf *rb;
+};
+
+/* 8-byte ring buffer record header structure */
+struct bpf_ringbuf_hdr {
+	u32 len;
+	u32 pg_off;
+};
+
+static struct bpf_ringbuf *bpf_ringbuf_area_alloc(size_t data_sz, int numa_node)
+{
+	const gfp_t flags = GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL |
+			    __GFP_NOWARN | __GFP_ZERO;
+	int nr_meta_pages = RINGBUF_PGOFF + RINGBUF_POS_PAGES;
+	int nr_data_pages = data_sz >> PAGE_SHIFT;
+	int nr_pages = nr_meta_pages + nr_data_pages;
+	struct page **pages, *page;
+	struct bpf_ringbuf *rb;
+	size_t array_size;
+	int i;
+
+	/* Each data page is mapped twice to allow "virtual"
+	 * continuous read of samples wrapping around the end of ring
+	 * buffer area:
+	 * ------------------------------------------------------
+	 * | meta pages |  real data pages  |  same data pages  |
+	 * ------------------------------------------------------
+	 * |            | 1 2 3 4 5 6 7 8 9 | 1 2 3 4 5 6 7 8 9 |
+	 * ------------------------------------------------------
+	 * |            | TA             DA | TA             DA |
+	 * ------------------------------------------------------
+	 *                               ^^^^^^^
+	 *                                  |
+	 * Here, no need to worry about special handling of wrapped-around
+	 * data due to double-mapped data pages. This works both in kernel and
+	 * when mmap()'ed in user-space, simplifying both kernel and
+	 * user-space implementations significantly.
+	 */
+	array_size = (nr_meta_pages + 2 * nr_data_pages) * sizeof(*pages);
+	pages = bpf_map_area_alloc(array_size, numa_node);
+	if (!pages)
+		return NULL;
+
+	for (i = 0; i < nr_pages; i++) {
+		page = alloc_pages_node(numa_node, flags, 0);
+		if (!page) {
+			nr_pages = i;
+			goto err_free_pages;
+		}
+		pages[i] = page;
+		if (i >= nr_meta_pages)
+			pages[nr_data_pages + i] = page;
+	}
+
+	rb = vmap(pages, nr_meta_pages + 2 * nr_data_pages,
+		  VM_MAP | VM_USERMAP, PAGE_KERNEL);
+	if (rb) {
+		kmemleak_not_leak(pages);
+		rb->pages = pages;
+		rb->nr_pages = nr_pages;
+		return rb;
+	}
+
+err_free_pages:
+	for (i = 0; i < nr_pages; i++)
+		__free_page(pages[i]);
+	bpf_map_area_free(pages);
+	return NULL;
+}
+
+static void bpf_ringbuf_notify(struct irq_work *work)
+{
+	struct bpf_ringbuf *rb = container_of(work, struct bpf_ringbuf, work);
+
+	wake_up_all(&rb->waitq);
+}
+
+static struct bpf_ringbuf *bpf_ringbuf_alloc(size_t data_sz, int numa_node)
+{
+	struct bpf_ringbuf *rb;
+
+	rb = bpf_ringbuf_area_alloc(data_sz, numa_node);
+	if (!rb)
+		return NULL;
+
+	spin_lock_init(&rb->spinlock);
+	atomic_set(&rb->busy, 0);
+	init_waitqueue_head(&rb->waitq);
+	init_irq_work(&rb->work, bpf_ringbuf_notify);
+
+	rb->mask = data_sz - 1;
+	rb->consumer_pos = 0;
+	rb->producer_pos = 0;
+
+	return rb;
+}
+
+static struct bpf_map *ringbuf_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_ringbuf_map *rb_map;
+
+	if (attr->map_flags & ~RINGBUF_CREATE_FLAG_MASK)
+		return ERR_PTR(-EINVAL);
+
+	if (attr->key_size || attr->value_size ||
+	    !is_power_of_2(attr->max_entries) ||
+	    !PAGE_ALIGNED(attr->max_entries))
+		return ERR_PTR(-EINVAL);
+
+#ifdef CONFIG_64BIT
+	/* on 32-bit arch, it's impossible to overflow record's hdr->pgoff */
+	if (attr->max_entries > RINGBUF_MAX_DATA_SZ)
+		return ERR_PTR(-E2BIG);
+#endif
+
+	rb_map = bpf_map_area_alloc(sizeof(*rb_map), NUMA_NO_NODE);
+	if (!rb_map)
+		return ERR_PTR(-ENOMEM);
+
+	bpf_map_init_from_attr(&rb_map->map, attr);
+
+	rb_map->rb = bpf_ringbuf_alloc(attr->max_entries, rb_map->map.numa_node);
+	if (!rb_map->rb) {
+		bpf_map_area_free(rb_map);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return &rb_map->map;
+}
+
+static void bpf_ringbuf_free(struct bpf_ringbuf *rb)
+{
+	/* copy pages pointer and nr_pages to local variable, as we are going
+	 * to unmap rb itself with vunmap() below
+	 */
+	struct page **pages = rb->pages;
+	int i, nr_pages = rb->nr_pages;
+
+	vunmap(rb);
+	for (i = 0; i < nr_pages; i++)
+		__free_page(pages[i]);
+	bpf_map_area_free(pages);
+}
+
+static void ringbuf_map_free(struct bpf_map *map)
+{
+	struct bpf_ringbuf_map *rb_map;
+
+	rb_map = container_of(map, struct bpf_ringbuf_map, map);
+	bpf_ringbuf_free(rb_map->rb);
+	bpf_map_area_free(rb_map);
+}
+
+static void *ringbuf_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	return ERR_PTR(-ENOTSUPP);
+}
+
+static int ringbuf_map_update_elem(struct bpf_map *map, void *key, void *value,
+				   u64 flags)
+{
+	return -ENOTSUPP;
+}
+
+static int ringbuf_map_delete_elem(struct bpf_map *map, void *key)
+{
+	return -ENOTSUPP;
+}
+
+static int ringbuf_map_get_next_key(struct bpf_map *map, void *key,
+				    void *next_key)
+{
+	return -ENOTSUPP;
+}
+
+static int ringbuf_map_mmap_kern(struct bpf_map *map, struct vm_area_struct *vma)
+{
+	struct bpf_ringbuf_map *rb_map;
+
+	rb_map = container_of(map, struct bpf_ringbuf_map, map);
+
+	if (vma->vm_flags & VM_WRITE) {
+		/* allow writable mapping for the consumer_pos only */
+		if (vma->vm_pgoff != 0 || vma->vm_end - vma->vm_start != PAGE_SIZE)
+			return -EPERM;
+	} else {
+		vma->vm_flags &= ~VM_MAYWRITE;
+	}
+	/* remap_vmalloc_range() checks size and offset constraints */
+	return remap_vmalloc_range(vma, rb_map->rb,
+				   vma->vm_pgoff + RINGBUF_PGOFF);
+}
+
+static int ringbuf_map_mmap_user(struct bpf_map *map, struct vm_area_struct *vma)
+{
+	struct bpf_ringbuf_map *rb_map;
+
+	rb_map = container_of(map, struct bpf_ringbuf_map, map);
+
+	if (vma->vm_flags & VM_WRITE) {
+		if (vma->vm_pgoff == 0)
+			/* Disallow writable mappings to the consumer pointer,
+			 * and allow writable mappings to both the producer
+			 * position, and the ring buffer data itself.
+			 */
+			return -EPERM;
+	} else {
+		vma->vm_flags &= ~VM_MAYWRITE;
+	}
+	/* remap_vmalloc_range() checks size and offset constraints */
+	return remap_vmalloc_range(vma, rb_map->rb, vma->vm_pgoff + RINGBUF_PGOFF);
+}
+
+static unsigned long ringbuf_avail_data_sz(struct bpf_ringbuf *rb)
+{
+	unsigned long cons_pos, prod_pos;
+
+	cons_pos = smp_load_acquire(&rb->consumer_pos);
+	prod_pos = smp_load_acquire(&rb->producer_pos);
+	return prod_pos - cons_pos;
+}
+
+static u32 ringbuf_total_data_sz(const struct bpf_ringbuf *rb)
+{
+	return rb->mask + 1;
+}
+
+static __poll_t ringbuf_map_poll_kern(struct bpf_map *map, struct file *filp,
+				      struct poll_table_struct *pts)
+{
+	struct bpf_ringbuf_map *rb_map;
+
+	rb_map = container_of(map, struct bpf_ringbuf_map, map);
+	poll_wait(filp, &rb_map->rb->waitq, pts);
+
+	if (ringbuf_avail_data_sz(rb_map->rb))
+		return EPOLLIN | EPOLLRDNORM;
+	return 0;
+}
+
+static __poll_t ringbuf_map_poll_user(struct bpf_map *map, struct file *filp,
+				      struct poll_table_struct *pts)
+{
+	struct bpf_ringbuf_map *rb_map;
+
+	rb_map = container_of(map, struct bpf_ringbuf_map, map);
+	poll_wait(filp, &rb_map->rb->waitq, pts);
+
+	if (ringbuf_avail_data_sz(rb_map->rb) < ringbuf_total_data_sz(rb_map->rb))
+		return EPOLLOUT | EPOLLWRNORM;
+	return 0;
+}
+
+BTF_ID_LIST_SINGLE(ringbuf_map_btf_ids, struct, bpf_ringbuf_map)
+const struct bpf_map_ops ringbuf_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc = ringbuf_map_alloc,
+	.map_free = ringbuf_map_free,
+	.map_mmap = ringbuf_map_mmap_kern,
+	.map_poll = ringbuf_map_poll_kern,
+	.map_lookup_elem = ringbuf_map_lookup_elem,
+	.map_update_elem = ringbuf_map_update_elem,
+	.map_delete_elem = ringbuf_map_delete_elem,
+	.map_get_next_key = ringbuf_map_get_next_key,
+	.map_btf_id = &ringbuf_map_btf_ids[0],
+};
+
+BTF_ID_LIST_SINGLE(user_ringbuf_map_btf_ids, struct, bpf_ringbuf_map)
+const struct bpf_map_ops user_ringbuf_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc = ringbuf_map_alloc,
+	.map_free = ringbuf_map_free,
+	.map_mmap = ringbuf_map_mmap_user,
+	.map_poll = ringbuf_map_poll_user,
+	.map_lookup_elem = ringbuf_map_lookup_elem,
+	.map_update_elem = ringbuf_map_update_elem,
+	.map_delete_elem = ringbuf_map_delete_elem,
+	.map_get_next_key = ringbuf_map_get_next_key,
+	.map_btf_id = &user_ringbuf_map_btf_ids[0],
+};
+
+/* Given pointer to ring buffer record metadata and struct bpf_ringbuf itself,
+ * calculate offset from record metadata to ring buffer in pages, rounded
+ * down. This page offset is stored as part of record metadata and allows to
+ * restore struct bpf_ringbuf * from record pointer. This page offset is
+ * stored at offset 4 of record metadata header.
+ */
+static size_t bpf_ringbuf_rec_pg_off(struct bpf_ringbuf *rb,
+				     struct bpf_ringbuf_hdr *hdr)
+{
+	return ((void *)hdr - (void *)rb) >> PAGE_SHIFT;
+}
+
+/* Given pointer to ring buffer record header, restore pointer to struct
+ * bpf_ringbuf itself by using page offset stored at offset 4
+ */
+static struct bpf_ringbuf *
+bpf_ringbuf_restore_from_rec(struct bpf_ringbuf_hdr *hdr)
+{
+	unsigned long addr = (unsigned long)(void *)hdr;
+	unsigned long off = (unsigned long)hdr->pg_off << PAGE_SHIFT;
+
+	return (void*)((addr & PAGE_MASK) - off);
+}
+
+static void *__bpf_ringbuf_reserve(struct bpf_ringbuf *rb, u64 size)
+{
+	unsigned long cons_pos, prod_pos, new_prod_pos, flags;
+	u32 len, pg_off;
+	struct bpf_ringbuf_hdr *hdr;
+
+	if (unlikely(size > RINGBUF_MAX_RECORD_SZ))
+		return NULL;
+
+	len = round_up(size + BPF_RINGBUF_HDR_SZ, 8);
+	if (len > ringbuf_total_data_sz(rb))
+		return NULL;
+
+	cons_pos = smp_load_acquire(&rb->consumer_pos);
+
+	if (in_nmi()) {
+		if (!spin_trylock_irqsave(&rb->spinlock, flags))
+			return NULL;
+	} else {
+		spin_lock_irqsave(&rb->spinlock, flags);
+	}
+
+	prod_pos = rb->producer_pos;
+	new_prod_pos = prod_pos + len;
+
+	/* check for out of ringbuf space by ensuring producer position
+	 * doesn't advance more than (ringbuf_size - 1) ahead
+	 */
+	if (new_prod_pos - cons_pos > rb->mask) {
+		spin_unlock_irqrestore(&rb->spinlock, flags);
+		return NULL;
+	}
+
+	hdr = (void *)rb->data + (prod_pos & rb->mask);
+	pg_off = bpf_ringbuf_rec_pg_off(rb, hdr);
+	hdr->len = size | BPF_RINGBUF_BUSY_BIT;
+	hdr->pg_off = pg_off;
+
+	/* pairs with consumer's smp_load_acquire() */
+	smp_store_release(&rb->producer_pos, new_prod_pos);
+
+	spin_unlock_irqrestore(&rb->spinlock, flags);
+
+	return (void *)hdr + BPF_RINGBUF_HDR_SZ;
+}
+
+BPF_CALL_3(bpf_ringbuf_reserve, struct bpf_map *, map, u64, size, u64, flags)
+{
+	struct bpf_ringbuf_map *rb_map;
+
+	if (unlikely(flags))
+		return 0;
+
+	rb_map = container_of(map, struct bpf_ringbuf_map, map);
+	return (unsigned long)__bpf_ringbuf_reserve(rb_map->rb, size);
+}
+
+const struct bpf_func_proto bpf_ringbuf_reserve_proto = {
+	.func		= bpf_ringbuf_reserve,
+	.ret_type	= RET_PTR_TO_ALLOC_MEM_OR_NULL,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_CONST_ALLOC_SIZE_OR_ZERO,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+static void bpf_ringbuf_commit(void *sample, u64 flags, bool discard)
+{
+	unsigned long rec_pos, cons_pos;
+	struct bpf_ringbuf_hdr *hdr;
+	struct bpf_ringbuf *rb;
+	u32 new_len;
+
+	hdr = sample - BPF_RINGBUF_HDR_SZ;
+	rb = bpf_ringbuf_restore_from_rec(hdr);
+	new_len = hdr->len ^ BPF_RINGBUF_BUSY_BIT;
+	if (discard)
+		new_len |= BPF_RINGBUF_DISCARD_BIT;
+
+	/* update record header with correct final size prefix */
+	xchg(&hdr->len, new_len);
+
+	/* if consumer caught up and is waiting for our record, notify about
+	 * new data availability
+	 */
+	rec_pos = (void *)hdr - (void *)rb->data;
+	cons_pos = smp_load_acquire(&rb->consumer_pos) & rb->mask;
+
+	if (flags & BPF_RB_FORCE_WAKEUP)
+		irq_work_queue(&rb->work);
+	else if (cons_pos == rec_pos && !(flags & BPF_RB_NO_WAKEUP))
+		irq_work_queue(&rb->work);
+}
+
+BPF_CALL_2(bpf_ringbuf_submit, void *, sample, u64, flags)
+{
+	bpf_ringbuf_commit(sample, flags, false /* discard */);
+	return 0;
+}
+
+const struct bpf_func_proto bpf_ringbuf_submit_proto = {
+	.func		= bpf_ringbuf_submit,
+	.ret_type	= RET_VOID,
+	.arg1_type	= ARG_PTR_TO_ALLOC_MEM | OBJ_RELEASE,
+	.arg2_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_2(bpf_ringbuf_discard, void *, sample, u64, flags)
+{
+	bpf_ringbuf_commit(sample, flags, true /* discard */);
+	return 0;
+}
+
+const struct bpf_func_proto bpf_ringbuf_discard_proto = {
+	.func		= bpf_ringbuf_discard,
+	.ret_type	= RET_VOID,
+	.arg1_type	= ARG_PTR_TO_ALLOC_MEM | OBJ_RELEASE,
+	.arg2_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_4(bpf_ringbuf_output, struct bpf_map *, map, void *, data, u64, size,
+	   u64, flags)
+{
+	struct bpf_ringbuf_map *rb_map;
+	void *rec;
+
+	if (unlikely(flags & ~(BPF_RB_NO_WAKEUP | BPF_RB_FORCE_WAKEUP)))
+		return -EINVAL;
+
+	rb_map = container_of(map, struct bpf_ringbuf_map, map);
+	rec = __bpf_ringbuf_reserve(rb_map->rb, size);
+	if (!rec)
+		return -EAGAIN;
+
+	memcpy(rec, data, size);
+	bpf_ringbuf_commit(rec, flags, false /* discard */);
+	return 0;
+}
+
+const struct bpf_func_proto bpf_ringbuf_output_proto = {
+	.func		= bpf_ringbuf_output,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg3_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_2(bpf_ringbuf_query, struct bpf_map *, map, u64, flags)
+{
+	struct bpf_ringbuf *rb;
+
+	rb = container_of(map, struct bpf_ringbuf_map, map)->rb;
+
+	switch (flags) {
+	case BPF_RB_AVAIL_DATA:
+		return ringbuf_avail_data_sz(rb);
+	case BPF_RB_RING_SIZE:
+		return ringbuf_total_data_sz(rb);
+	case BPF_RB_CONS_POS:
+		return smp_load_acquire(&rb->consumer_pos);
+	case BPF_RB_PROD_POS:
+		return smp_load_acquire(&rb->producer_pos);
+	default:
+		return 0;
+	}
+}
+
+const struct bpf_func_proto bpf_ringbuf_query_proto = {
+	.func		= bpf_ringbuf_query,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_4(bpf_ringbuf_reserve_dynptr, struct bpf_map *, map, u32, size, u64, flags,
+	   struct bpf_dynptr_kern *, ptr)
+{
+	struct bpf_ringbuf_map *rb_map;
+	void *sample;
+	int err;
+
+	if (unlikely(flags)) {
+		bpf_dynptr_set_null(ptr);
+		return -EINVAL;
+	}
+
+	err = bpf_dynptr_check_size(size);
+	if (err) {
+		bpf_dynptr_set_null(ptr);
+		return err;
+	}
+
+	rb_map = container_of(map, struct bpf_ringbuf_map, map);
+
+	sample = __bpf_ringbuf_reserve(rb_map->rb, size);
+	if (!sample) {
+		bpf_dynptr_set_null(ptr);
+		return -EINVAL;
+	}
+
+	bpf_dynptr_init(ptr, sample, BPF_DYNPTR_TYPE_RINGBUF, 0, size);
+
+	return 0;
+}
+
+const struct bpf_func_proto bpf_ringbuf_reserve_dynptr_proto = {
+	.func		= bpf_ringbuf_reserve_dynptr,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_RINGBUF | MEM_UNINIT,
+};
+
+BPF_CALL_2(bpf_ringbuf_submit_dynptr, struct bpf_dynptr_kern *, ptr, u64, flags)
+{
+	if (!ptr->data)
+		return 0;
+
+	bpf_ringbuf_commit(ptr->data, flags, false /* discard */);
+
+	bpf_dynptr_set_null(ptr);
+
+	return 0;
+}
+
+const struct bpf_func_proto bpf_ringbuf_submit_dynptr_proto = {
+	.func		= bpf_ringbuf_submit_dynptr,
+	.ret_type	= RET_VOID,
+	.arg1_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_RINGBUF | OBJ_RELEASE,
+	.arg2_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_2(bpf_ringbuf_discard_dynptr, struct bpf_dynptr_kern *, ptr, u64, flags)
+{
+	if (!ptr->data)
+		return 0;
+
+	bpf_ringbuf_commit(ptr->data, flags, true /* discard */);
+
+	bpf_dynptr_set_null(ptr);
+
+	return 0;
+}
+
+const struct bpf_func_proto bpf_ringbuf_discard_dynptr_proto = {
+	.func		= bpf_ringbuf_discard_dynptr,
+	.ret_type	= RET_VOID,
+	.arg1_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_RINGBUF | OBJ_RELEASE,
+	.arg2_type	= ARG_ANYTHING,
+};
+
+static int __bpf_user_ringbuf_peek(struct bpf_ringbuf *rb, void **sample, u32 *size)
+{
+	int err;
+	u32 hdr_len, sample_len, total_len, flags, *hdr;
+	u64 cons_pos, prod_pos;
+
+	/* Synchronizes with smp_store_release() in user-space producer. */
+	prod_pos = smp_load_acquire(&rb->producer_pos);
+	if (prod_pos % 8)
+		return -EINVAL;
+
+	/* Synchronizes with smp_store_release() in __bpf_user_ringbuf_sample_release() */
+	cons_pos = smp_load_acquire(&rb->consumer_pos);
+	if (cons_pos >= prod_pos)
+		return -ENODATA;
+
+	hdr = (u32 *)((uintptr_t)rb->data + (uintptr_t)(cons_pos & rb->mask));
+	/* Synchronizes with smp_store_release() in user-space producer. */
+	hdr_len = smp_load_acquire(hdr);
+	flags = hdr_len & (BPF_RINGBUF_BUSY_BIT | BPF_RINGBUF_DISCARD_BIT);
+	sample_len = hdr_len & ~flags;
+	total_len = round_up(sample_len + BPF_RINGBUF_HDR_SZ, 8);
+
+	/* The sample must fit within the region advertised by the producer position. */
+	if (total_len > prod_pos - cons_pos)
+		return -EINVAL;
+
+	/* The sample must fit within the data region of the ring buffer. */
+	if (total_len > ringbuf_total_data_sz(rb))
+		return -E2BIG;
+
+	/* The sample must fit into a struct bpf_dynptr. */
+	err = bpf_dynptr_check_size(sample_len);
+	if (err)
+		return -E2BIG;
+
+	if (flags & BPF_RINGBUF_DISCARD_BIT) {
+		/* If the discard bit is set, the sample should be skipped.
+		 *
+		 * Update the consumer pos, and return -EAGAIN so the caller
+		 * knows to skip this sample and try to read the next one.
+		 */
+		smp_store_release(&rb->consumer_pos, cons_pos + total_len);
+		return -EAGAIN;
+	}
+
+	if (flags & BPF_RINGBUF_BUSY_BIT)
+		return -ENODATA;
+
+	*sample = (void *)((uintptr_t)rb->data +
+			   (uintptr_t)((cons_pos + BPF_RINGBUF_HDR_SZ) & rb->mask));
+	*size = sample_len;
+	return 0;
+}
+
+static void __bpf_user_ringbuf_sample_release(struct bpf_ringbuf *rb, size_t size, u64 flags)
+{
+	u64 consumer_pos;
+	u32 rounded_size = round_up(size + BPF_RINGBUF_HDR_SZ, 8);
+
+	/* Using smp_load_acquire() is unnecessary here, as the busy-bit
+	 * prevents another task from writing to consumer_pos after it was read
+	 * by this task with smp_load_acquire() in __bpf_user_ringbuf_peek().
+	 */
+	consumer_pos = rb->consumer_pos;
+	 /* Synchronizes with smp_load_acquire() in user-space producer. */
+	smp_store_release(&rb->consumer_pos, consumer_pos + rounded_size);
+}
+
+BPF_CALL_4(bpf_user_ringbuf_drain, struct bpf_map *, map,
+	   void *, callback_fn, void *, callback_ctx, u64, flags)
+{
+	struct bpf_ringbuf *rb;
+	long samples, discarded_samples = 0, ret = 0;
+	bpf_callback_t callback = (bpf_callback_t)callback_fn;
+	u64 wakeup_flags = BPF_RB_NO_WAKEUP | BPF_RB_FORCE_WAKEUP;
+	int busy = 0;
+
+	if (unlikely(flags & ~wakeup_flags))
+		return -EINVAL;
+
+	rb = container_of(map, struct bpf_ringbuf_map, map)->rb;
+
+	/* If another consumer is already consuming a sample, wait for them to finish. */
+	if (!atomic_try_cmpxchg(&rb->busy, &busy, 1))
+		return -EBUSY;
+
+	for (samples = 0; samples < BPF_MAX_USER_RINGBUF_SAMPLES && ret == 0; samples++) {
+		int err;
+		u32 size;
+		void *sample;
+		struct bpf_dynptr_kern dynptr;
+
+		err = __bpf_user_ringbuf_peek(rb, &sample, &size);
+		if (err) {
+			if (err == -ENODATA) {
+				break;
+			} else if (err == -EAGAIN) {
+				discarded_samples++;
+				continue;
+			} else {
+				ret = err;
+				goto schedule_work_return;
+			}
+		}
+
+		bpf_dynptr_init(&dynptr, sample, BPF_DYNPTR_TYPE_LOCAL, 0, size);
+		ret = callback((uintptr_t)&dynptr, (uintptr_t)callback_ctx, 0, 0, 0);
+		__bpf_user_ringbuf_sample_release(rb, size, flags);
+	}
+	ret = samples - discarded_samples;
+
+schedule_work_return:
+	/* Prevent the clearing of the busy-bit from being reordered before the
+	 * storing of any rb consumer or producer positions.
+	 */
+	smp_mb__before_atomic();
+	atomic_set(&rb->busy, 0);
+
+	if (flags & BPF_RB_FORCE_WAKEUP)
+		irq_work_queue(&rb->work);
+	else if (!(flags & BPF_RB_NO_WAKEUP) && samples > 0)
+		irq_work_queue(&rb->work);
+	return ret;
+}
+
+const struct bpf_func_proto bpf_user_ringbuf_drain_proto = {
+	.func		= bpf_user_ringbuf_drain,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_FUNC,
+	.arg3_type	= ARG_PTR_TO_STACK_OR_NULL,
+	.arg4_type	= ARG_ANYTHING,
+};
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
new file mode 100644
index 000000000..f86db3cf7
--- /dev/null
+++ b/kernel/bpf/stackmap.c
@@ -0,0 +1,677 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2016 Facebook
+ */
+#include <linux/bpf.h>
+#include <linux/jhash.h>
+#include <linux/filter.h>
+#include <linux/kernel.h>
+#include <linux/stacktrace.h>
+#include <linux/perf_event.h>
+#include <linux/btf_ids.h>
+#include <linux/buildid.h>
+#include "percpu_freelist.h"
+#include "mmap_unlock_work.h"
+
+#define STACK_CREATE_FLAG_MASK					\
+	(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY |	\
+	 BPF_F_STACK_BUILD_ID)
+
+struct stack_map_bucket {
+	struct pcpu_freelist_node fnode;
+	u32 hash;
+	u32 nr;
+	u64 data[];
+};
+
+struct bpf_stack_map {
+	struct bpf_map map;
+	void *elems;
+	struct pcpu_freelist freelist;
+	u32 n_buckets;
+	struct stack_map_bucket *buckets[];
+};
+
+static inline bool stack_map_use_build_id(struct bpf_map *map)
+{
+	return (map->map_flags & BPF_F_STACK_BUILD_ID);
+}
+
+static inline int stack_map_data_size(struct bpf_map *map)
+{
+	return stack_map_use_build_id(map) ?
+		sizeof(struct bpf_stack_build_id) : sizeof(u64);
+}
+
+static int prealloc_elems_and_freelist(struct bpf_stack_map *smap)
+{
+	u64 elem_size = sizeof(struct stack_map_bucket) +
+			(u64)smap->map.value_size;
+	int err;
+
+	smap->elems = bpf_map_area_alloc(elem_size * smap->map.max_entries,
+					 smap->map.numa_node);
+	if (!smap->elems)
+		return -ENOMEM;
+
+	err = pcpu_freelist_init(&smap->freelist);
+	if (err)
+		goto free_elems;
+
+	pcpu_freelist_populate(&smap->freelist, smap->elems, elem_size,
+			       smap->map.max_entries);
+	return 0;
+
+free_elems:
+	bpf_map_area_free(smap->elems);
+	return err;
+}
+
+/* Called from syscall */
+static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
+{
+	u32 value_size = attr->value_size;
+	struct bpf_stack_map *smap;
+	u64 cost, n_buckets;
+	int err;
+
+	if (!bpf_capable())
+		return ERR_PTR(-EPERM);
+
+	if (attr->map_flags & ~STACK_CREATE_FLAG_MASK)
+		return ERR_PTR(-EINVAL);
+
+	/* check sanity of attributes */
+	if (attr->max_entries == 0 || attr->key_size != 4 ||
+	    value_size < 8 || value_size % 8)
+		return ERR_PTR(-EINVAL);
+
+	BUILD_BUG_ON(sizeof(struct bpf_stack_build_id) % sizeof(u64));
+	if (attr->map_flags & BPF_F_STACK_BUILD_ID) {
+		if (value_size % sizeof(struct bpf_stack_build_id) ||
+		    value_size / sizeof(struct bpf_stack_build_id)
+		    > sysctl_perf_event_max_stack)
+			return ERR_PTR(-EINVAL);
+	} else if (value_size / 8 > sysctl_perf_event_max_stack)
+		return ERR_PTR(-EINVAL);
+
+	/* hash table size must be power of 2 */
+	n_buckets = roundup_pow_of_two(attr->max_entries);
+	if (!n_buckets)
+		return ERR_PTR(-E2BIG);
+
+	cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap);
+	smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr));
+	if (!smap)
+		return ERR_PTR(-ENOMEM);
+
+	bpf_map_init_from_attr(&smap->map, attr);
+	smap->n_buckets = n_buckets;
+
+	err = get_callchain_buffers(sysctl_perf_event_max_stack);
+	if (err)
+		goto free_smap;
+
+	err = prealloc_elems_and_freelist(smap);
+	if (err)
+		goto put_buffers;
+
+	return &smap->map;
+
+put_buffers:
+	put_callchain_buffers();
+free_smap:
+	bpf_map_area_free(smap);
+	return ERR_PTR(err);
+}
+
+static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
+					  u64 *ips, u32 trace_nr, bool user)
+{
+	int i;
+	struct mmap_unlock_irq_work *work = NULL;
+	bool irq_work_busy = bpf_mmap_unlock_get_irq_work(&work);
+	struct vm_area_struct *vma, *prev_vma = NULL;
+	const char *prev_build_id;
+
+	/* If the irq_work is in use, fall back to report ips. Same
+	 * fallback is used for kernel stack (!user) on a stackmap with
+	 * build_id.
+	 */
+	if (!user || !current || !current->mm || irq_work_busy ||
+	    !mmap_read_trylock(current->mm)) {
+		/* cannot access current->mm, fall back to ips */
+		for (i = 0; i < trace_nr; i++) {
+			id_offs[i].status = BPF_STACK_BUILD_ID_IP;
+			id_offs[i].ip = ips[i];
+			memset(id_offs[i].build_id, 0, BUILD_ID_SIZE_MAX);
+		}
+		return;
+	}
+
+	for (i = 0; i < trace_nr; i++) {
+		if (range_in_vma(prev_vma, ips[i], ips[i])) {
+			vma = prev_vma;
+			memcpy(id_offs[i].build_id, prev_build_id,
+			       BUILD_ID_SIZE_MAX);
+			goto build_id_valid;
+		}
+		vma = find_vma(current->mm, ips[i]);
+		if (!vma || build_id_parse(vma, id_offs[i].build_id, NULL)) {
+			/* per entry fall back to ips */
+			id_offs[i].status = BPF_STACK_BUILD_ID_IP;
+			id_offs[i].ip = ips[i];
+			memset(id_offs[i].build_id, 0, BUILD_ID_SIZE_MAX);
+			continue;
+		}
+build_id_valid:
+		id_offs[i].offset = (vma->vm_pgoff << PAGE_SHIFT) + ips[i]
+			- vma->vm_start;
+		id_offs[i].status = BPF_STACK_BUILD_ID_VALID;
+		prev_vma = vma;
+		prev_build_id = id_offs[i].build_id;
+	}
+	bpf_mmap_unlock_mm(work, current->mm);
+}
+
+static struct perf_callchain_entry *
+get_callchain_entry_for_task(struct task_struct *task, u32 max_depth)
+{
+#ifdef CONFIG_STACKTRACE
+	struct perf_callchain_entry *entry;
+	int rctx;
+
+	entry = get_callchain_entry(&rctx);
+
+	if (!entry)
+		return NULL;
+
+	entry->nr = stack_trace_save_tsk(task, (unsigned long *)entry->ip,
+					 max_depth, 0);
+
+	/* stack_trace_save_tsk() works on unsigned long array, while
+	 * perf_callchain_entry uses u64 array. For 32-bit systems, it is
+	 * necessary to fix this mismatch.
+	 */
+	if (__BITS_PER_LONG != 64) {
+		unsigned long *from = (unsigned long *) entry->ip;
+		u64 *to = entry->ip;
+		int i;
+
+		/* copy data from the end to avoid using extra buffer */
+		for (i = entry->nr - 1; i >= 0; i--)
+			to[i] = (u64)(from[i]);
+	}
+
+	put_callchain_entry(rctx);
+
+	return entry;
+#else /* CONFIG_STACKTRACE */
+	return NULL;
+#endif
+}
+
+static long __bpf_get_stackid(struct bpf_map *map,
+			      struct perf_callchain_entry *trace, u64 flags)
+{
+	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
+	struct stack_map_bucket *bucket, *new_bucket, *old_bucket;
+	u32 skip = flags & BPF_F_SKIP_FIELD_MASK;
+	u32 hash, id, trace_nr, trace_len;
+	bool user = flags & BPF_F_USER_STACK;
+	u64 *ips;
+	bool hash_matches;
+
+	if (trace->nr <= skip)
+		/* skipping more than usable stack trace */
+		return -EFAULT;
+
+	trace_nr = trace->nr - skip;
+	trace_len = trace_nr * sizeof(u64);
+	ips = trace->ip + skip;
+	hash = jhash2((u32 *)ips, trace_len / sizeof(u32), 0);
+	id = hash & (smap->n_buckets - 1);
+	bucket = READ_ONCE(smap->buckets[id]);
+
+	hash_matches = bucket && bucket->hash == hash;
+	/* fast cmp */
+	if (hash_matches && flags & BPF_F_FAST_STACK_CMP)
+		return id;
+
+	if (stack_map_use_build_id(map)) {
+		/* for build_id+offset, pop a bucket before slow cmp */
+		new_bucket = (struct stack_map_bucket *)
+			pcpu_freelist_pop(&smap->freelist);
+		if (unlikely(!new_bucket))
+			return -ENOMEM;
+		new_bucket->nr = trace_nr;
+		stack_map_get_build_id_offset(
+			(struct bpf_stack_build_id *)new_bucket->data,
+			ips, trace_nr, user);
+		trace_len = trace_nr * sizeof(struct bpf_stack_build_id);
+		if (hash_matches && bucket->nr == trace_nr &&
+		    memcmp(bucket->data, new_bucket->data, trace_len) == 0) {
+			pcpu_freelist_push(&smap->freelist, &new_bucket->fnode);
+			return id;
+		}
+		if (bucket && !(flags & BPF_F_REUSE_STACKID)) {
+			pcpu_freelist_push(&smap->freelist, &new_bucket->fnode);
+			return -EEXIST;
+		}
+	} else {
+		if (hash_matches && bucket->nr == trace_nr &&
+		    memcmp(bucket->data, ips, trace_len) == 0)
+			return id;
+		if (bucket && !(flags & BPF_F_REUSE_STACKID))
+			return -EEXIST;
+
+		new_bucket = (struct stack_map_bucket *)
+			pcpu_freelist_pop(&smap->freelist);
+		if (unlikely(!new_bucket))
+			return -ENOMEM;
+		memcpy(new_bucket->data, ips, trace_len);
+	}
+
+	new_bucket->hash = hash;
+	new_bucket->nr = trace_nr;
+
+	old_bucket = xchg(&smap->buckets[id], new_bucket);
+	if (old_bucket)
+		pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
+	return id;
+}
+
+BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map,
+	   u64, flags)
+{
+	u32 max_depth = map->value_size / stack_map_data_size(map);
+	u32 skip = flags & BPF_F_SKIP_FIELD_MASK;
+	bool user = flags & BPF_F_USER_STACK;
+	struct perf_callchain_entry *trace;
+	bool kernel = !user;
+
+	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
+			       BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID)))
+		return -EINVAL;
+
+	max_depth += skip;
+	if (max_depth > sysctl_perf_event_max_stack)
+		max_depth = sysctl_perf_event_max_stack;
+
+	trace = get_perf_callchain(regs, 0, kernel, user, max_depth,
+				   false, false);
+
+	if (unlikely(!trace))
+		/* couldn't fetch the stack trace */
+		return -EFAULT;
+
+	return __bpf_get_stackid(map, trace, flags);
+}
+
+const struct bpf_func_proto bpf_get_stackid_proto = {
+	.func		= bpf_get_stackid,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_CONST_MAP_PTR,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+static __u64 count_kernel_ip(struct perf_callchain_entry *trace)
+{
+	__u64 nr_kernel = 0;
+
+	while (nr_kernel < trace->nr) {
+		if (trace->ip[nr_kernel] == PERF_CONTEXT_USER)
+			break;
+		nr_kernel++;
+	}
+	return nr_kernel;
+}
+
+BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx,
+	   struct bpf_map *, map, u64, flags)
+{
+	struct perf_event *event = ctx->event;
+	struct perf_callchain_entry *trace;
+	bool kernel, user;
+	__u64 nr_kernel;
+	int ret;
+
+	/* perf_sample_data doesn't have callchain, use bpf_get_stackid */
+	if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN))
+		return bpf_get_stackid((unsigned long)(ctx->regs),
+				       (unsigned long) map, flags, 0, 0);
+
+	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
+			       BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID)))
+		return -EINVAL;
+
+	user = flags & BPF_F_USER_STACK;
+	kernel = !user;
+
+	trace = ctx->data->callchain;
+	if (unlikely(!trace))
+		return -EFAULT;
+
+	nr_kernel = count_kernel_ip(trace);
+
+	if (kernel) {
+		__u64 nr = trace->nr;
+
+		trace->nr = nr_kernel;
+		ret = __bpf_get_stackid(map, trace, flags);
+
+		/* restore nr */
+		trace->nr = nr;
+	} else { /* user */
+		u64 skip = flags & BPF_F_SKIP_FIELD_MASK;
+
+		skip += nr_kernel;
+		if (skip > BPF_F_SKIP_FIELD_MASK)
+			return -EFAULT;
+
+		flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip;
+		ret = __bpf_get_stackid(map, trace, flags);
+	}
+	return ret;
+}
+
+const struct bpf_func_proto bpf_get_stackid_proto_pe = {
+	.func		= bpf_get_stackid_pe,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_CONST_MAP_PTR,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task,
+			    struct perf_callchain_entry *trace_in,
+			    void *buf, u32 size, u64 flags)
+{
+	u32 trace_nr, copy_len, elem_size, num_elem, max_depth;
+	bool user_build_id = flags & BPF_F_USER_BUILD_ID;
+	bool crosstask = task && task != current;
+	u32 skip = flags & BPF_F_SKIP_FIELD_MASK;
+	bool user = flags & BPF_F_USER_STACK;
+	struct perf_callchain_entry *trace;
+	bool kernel = !user;
+	int err = -EINVAL;
+	u64 *ips;
+
+	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
+			       BPF_F_USER_BUILD_ID)))
+		goto clear;
+	if (kernel && user_build_id)
+		goto clear;
+
+	elem_size = (user && user_build_id) ? sizeof(struct bpf_stack_build_id)
+					    : sizeof(u64);
+	if (unlikely(size % elem_size))
+		goto clear;
+
+	/* cannot get valid user stack for task without user_mode regs */
+	if (task && user && !user_mode(regs))
+		goto err_fault;
+
+	/* get_perf_callchain does not support crosstask user stack walking
+	 * but returns an empty stack instead of NULL.
+	 */
+	if (crosstask && user) {
+		err = -EOPNOTSUPP;
+		goto clear;
+	}
+
+	num_elem = size / elem_size;
+	max_depth = num_elem + skip;
+	if (sysctl_perf_event_max_stack < max_depth)
+		max_depth = sysctl_perf_event_max_stack;
+
+	if (trace_in)
+		trace = trace_in;
+	else if (kernel && task)
+		trace = get_callchain_entry_for_task(task, max_depth);
+	else
+		trace = get_perf_callchain(regs, 0, kernel, user, max_depth,
+					   crosstask, false);
+	if (unlikely(!trace))
+		goto err_fault;
+
+	if (trace->nr < skip)
+		goto err_fault;
+
+	trace_nr = trace->nr - skip;
+	trace_nr = (trace_nr <= num_elem) ? trace_nr : num_elem;
+	copy_len = trace_nr * elem_size;
+
+	ips = trace->ip + skip;
+	if (user && user_build_id)
+		stack_map_get_build_id_offset(buf, ips, trace_nr, user);
+	else
+		memcpy(buf, ips, copy_len);
+
+	if (size > copy_len)
+		memset(buf + copy_len, 0, size - copy_len);
+	return copy_len;
+
+err_fault:
+	err = -EFAULT;
+clear:
+	memset(buf, 0, size);
+	return err;
+}
+
+BPF_CALL_4(bpf_get_stack, struct pt_regs *, regs, void *, buf, u32, size,
+	   u64, flags)
+{
+	return __bpf_get_stack(regs, NULL, NULL, buf, size, flags);
+}
+
+const struct bpf_func_proto bpf_get_stack_proto = {
+	.func		= bpf_get_stack,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg3_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_4(bpf_get_task_stack, struct task_struct *, task, void *, buf,
+	   u32, size, u64, flags)
+{
+	struct pt_regs *regs;
+	long res = -EINVAL;
+
+	if (!try_get_task_stack(task))
+		return -EFAULT;
+
+	regs = task_pt_regs(task);
+	if (regs)
+		res = __bpf_get_stack(regs, task, NULL, buf, size, flags);
+	put_task_stack(task);
+
+	return res;
+}
+
+const struct bpf_func_proto bpf_get_task_stack_proto = {
+	.func		= bpf_get_task_stack,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_BTF_ID,
+	.arg1_btf_id	= &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
+	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg3_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx,
+	   void *, buf, u32, size, u64, flags)
+{
+	struct pt_regs *regs = (struct pt_regs *)(ctx->regs);
+	struct perf_event *event = ctx->event;
+	struct perf_callchain_entry *trace;
+	bool kernel, user;
+	int err = -EINVAL;
+	__u64 nr_kernel;
+
+	if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN))
+		return __bpf_get_stack(regs, NULL, NULL, buf, size, flags);
+
+	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
+			       BPF_F_USER_BUILD_ID)))
+		goto clear;
+
+	user = flags & BPF_F_USER_STACK;
+	kernel = !user;
+
+	err = -EFAULT;
+	trace = ctx->data->callchain;
+	if (unlikely(!trace))
+		goto clear;
+
+	nr_kernel = count_kernel_ip(trace);
+
+	if (kernel) {
+		__u64 nr = trace->nr;
+
+		trace->nr = nr_kernel;
+		err = __bpf_get_stack(regs, NULL, trace, buf, size, flags);
+
+		/* restore nr */
+		trace->nr = nr;
+	} else { /* user */
+		u64 skip = flags & BPF_F_SKIP_FIELD_MASK;
+
+		skip += nr_kernel;
+		if (skip > BPF_F_SKIP_FIELD_MASK)
+			goto clear;
+
+		flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip;
+		err = __bpf_get_stack(regs, NULL, trace, buf, size, flags);
+	}
+	return err;
+
+clear:
+	memset(buf, 0, size);
+	return err;
+
+}
+
+const struct bpf_func_proto bpf_get_stack_proto_pe = {
+	.func		= bpf_get_stack_pe,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg3_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+/* Called from eBPF program */
+static void *stack_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
+/* Called from syscall */
+int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
+{
+	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
+	struct stack_map_bucket *bucket, *old_bucket;
+	u32 id = *(u32 *)key, trace_len;
+
+	if (unlikely(id >= smap->n_buckets))
+		return -ENOENT;
+
+	bucket = xchg(&smap->buckets[id], NULL);
+	if (!bucket)
+		return -ENOENT;
+
+	trace_len = bucket->nr * stack_map_data_size(map);
+	memcpy(value, bucket->data, trace_len);
+	memset(value + trace_len, 0, map->value_size - trace_len);
+
+	old_bucket = xchg(&smap->buckets[id], bucket);
+	if (old_bucket)
+		pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
+	return 0;
+}
+
+static int stack_map_get_next_key(struct bpf_map *map, void *key,
+				  void *next_key)
+{
+	struct bpf_stack_map *smap = container_of(map,
+						  struct bpf_stack_map, map);
+	u32 id;
+
+	WARN_ON_ONCE(!rcu_read_lock_held());
+
+	if (!key) {
+		id = 0;
+	} else {
+		id = *(u32 *)key;
+		if (id >= smap->n_buckets || !smap->buckets[id])
+			id = 0;
+		else
+			id++;
+	}
+
+	while (id < smap->n_buckets && !smap->buckets[id])
+		id++;
+
+	if (id >= smap->n_buckets)
+		return -ENOENT;
+
+	*(u32 *)next_key = id;
+	return 0;
+}
+
+static int stack_map_update_elem(struct bpf_map *map, void *key, void *value,
+				 u64 map_flags)
+{
+	return -EINVAL;
+}
+
+/* Called from syscall or from eBPF program */
+static int stack_map_delete_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
+	struct stack_map_bucket *old_bucket;
+	u32 id = *(u32 *)key;
+
+	if (unlikely(id >= smap->n_buckets))
+		return -E2BIG;
+
+	old_bucket = xchg(&smap->buckets[id], NULL);
+	if (old_bucket) {
+		pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
+		return 0;
+	} else {
+		return -ENOENT;
+	}
+}
+
+/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
+static void stack_map_free(struct bpf_map *map)
+{
+	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
+
+	bpf_map_area_free(smap->elems);
+	pcpu_freelist_destroy(&smap->freelist);
+	bpf_map_area_free(smap);
+	put_callchain_buffers();
+}
+
+BTF_ID_LIST_SINGLE(stack_trace_map_btf_ids, struct, bpf_stack_map)
+const struct bpf_map_ops stack_trace_map_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc = stack_map_alloc,
+	.map_free = stack_map_free,
+	.map_get_next_key = stack_map_get_next_key,
+	.map_lookup_elem = stack_map_lookup_elem,
+	.map_update_elem = stack_map_update_elem,
+	.map_delete_elem = stack_map_delete_elem,
+	.map_check_btf = map_check_no_btf,
+	.map_btf_id = &stack_trace_map_btf_ids[0],
+};
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
new file mode 100644
index 000000000..8d0c38a8d
--- /dev/null
+++ b/kernel/bpf/syscall.c
@@ -0,0 +1,5356 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ */
+#include <linux/bpf.h>
+#include <linux/bpf-cgroup.h>
+#include <linux/bpf_trace.h>
+#include <linux/bpf_lirc.h>
+#include <linux/bpf_verifier.h>
+#include <linux/bsearch.h>
+#include <linux/btf.h>
+#include <linux/syscalls.h>
+#include <linux/slab.h>
+#include <linux/sched/signal.h>
+#include <linux/vmalloc.h>
+#include <linux/mmzone.h>
+#include <linux/anon_inodes.h>
+#include <linux/fdtable.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/license.h>
+#include <linux/filter.h>
+#include <linux/kernel.h>
+#include <linux/idr.h>
+#include <linux/cred.h>
+#include <linux/timekeeping.h>
+#include <linux/ctype.h>
+#include <linux/nospec.h>
+#include <linux/audit.h>
+#include <uapi/linux/btf.h>
+#include <linux/pgtable.h>
+#include <linux/bpf_lsm.h>
+#include <linux/poll.h>
+#include <linux/sort.h>
+#include <linux/bpf-netns.h>
+#include <linux/rcupdate_trace.h>
+#include <linux/memcontrol.h>
+#include <linux/trace_events.h>
+
+#define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \
+			  (map)->map_type == BPF_MAP_TYPE_CGROUP_ARRAY || \
+			  (map)->map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS)
+#define IS_FD_PROG_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PROG_ARRAY)
+#define IS_FD_HASH(map) ((map)->map_type == BPF_MAP_TYPE_HASH_OF_MAPS)
+#define IS_FD_MAP(map) (IS_FD_ARRAY(map) || IS_FD_PROG_ARRAY(map) || \
+			IS_FD_HASH(map))
+
+#define BPF_OBJ_FLAG_MASK   (BPF_F_RDONLY | BPF_F_WRONLY)
+
+DEFINE_PER_CPU(int, bpf_prog_active);
+static DEFINE_IDR(prog_idr);
+static DEFINE_SPINLOCK(prog_idr_lock);
+static DEFINE_IDR(map_idr);
+static DEFINE_SPINLOCK(map_idr_lock);
+static DEFINE_IDR(link_idr);
+static DEFINE_SPINLOCK(link_idr_lock);
+
+int sysctl_unprivileged_bpf_disabled __read_mostly =
+	IS_BUILTIN(CONFIG_BPF_UNPRIV_DEFAULT_OFF) ? 2 : 0;
+
+static const struct bpf_map_ops * const bpf_map_types[] = {
+#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
+#define BPF_MAP_TYPE(_id, _ops) \
+	[_id] = &_ops,
+#define BPF_LINK_TYPE(_id, _name)
+#include <linux/bpf_types.h>
+#undef BPF_PROG_TYPE
+#undef BPF_MAP_TYPE
+#undef BPF_LINK_TYPE
+};
+
+/*
+ * If we're handed a bigger struct than we know of, ensure all the unknown bits
+ * are 0 - i.e. new user-space does not rely on any kernel feature extensions
+ * we don't know about yet.
+ *
+ * There is a ToCToU between this function call and the following
+ * copy_from_user() call. However, this is not a concern since this function is
+ * meant to be a future-proofing of bits.
+ */
+int bpf_check_uarg_tail_zero(bpfptr_t uaddr,
+			     size_t expected_size,
+			     size_t actual_size)
+{
+	int res;
+
+	if (unlikely(actual_size > PAGE_SIZE))	/* silly large */
+		return -E2BIG;
+
+	if (actual_size <= expected_size)
+		return 0;
+
+	if (uaddr.is_kernel)
+		res = memchr_inv(uaddr.kernel + expected_size, 0,
+				 actual_size - expected_size) == NULL;
+	else
+		res = check_zeroed_user(uaddr.user + expected_size,
+					actual_size - expected_size);
+	if (res < 0)
+		return res;
+	return res ? 0 : -E2BIG;
+}
+
+const struct bpf_map_ops bpf_map_offload_ops = {
+	.map_meta_equal = bpf_map_meta_equal,
+	.map_alloc = bpf_map_offload_map_alloc,
+	.map_free = bpf_map_offload_map_free,
+	.map_check_btf = map_check_no_btf,
+};
+
+static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
+{
+	const struct bpf_map_ops *ops;
+	u32 type = attr->map_type;
+	struct bpf_map *map;
+	int err;
+
+	if (type >= ARRAY_SIZE(bpf_map_types))
+		return ERR_PTR(-EINVAL);
+	type = array_index_nospec(type, ARRAY_SIZE(bpf_map_types));
+	ops = bpf_map_types[type];
+	if (!ops)
+		return ERR_PTR(-EINVAL);
+
+	if (ops->map_alloc_check) {
+		err = ops->map_alloc_check(attr);
+		if (err)
+			return ERR_PTR(err);
+	}
+	if (attr->map_ifindex)
+		ops = &bpf_map_offload_ops;
+	map = ops->map_alloc(attr);
+	if (IS_ERR(map))
+		return map;
+	map->ops = ops;
+	map->map_type = type;
+	return map;
+}
+
+static void bpf_map_write_active_inc(struct bpf_map *map)
+{
+	atomic64_inc(&map->writecnt);
+}
+
+static void bpf_map_write_active_dec(struct bpf_map *map)
+{
+	atomic64_dec(&map->writecnt);
+}
+
+bool bpf_map_write_active(const struct bpf_map *map)
+{
+	return atomic64_read(&map->writecnt) != 0;
+}
+
+static u32 bpf_map_value_size(const struct bpf_map *map)
+{
+	if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+	    map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
+	    map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY ||
+	    map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
+		return round_up(map->value_size, 8) * num_possible_cpus();
+	else if (IS_FD_MAP(map))
+		return sizeof(u32);
+	else
+		return  map->value_size;
+}
+
+static void maybe_wait_bpf_programs(struct bpf_map *map)
+{
+	/* Wait for any running BPF programs to complete so that
+	 * userspace, when we return to it, knows that all programs
+	 * that could be running use the new map value.
+	 */
+	if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS ||
+	    map->map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS)
+		synchronize_rcu();
+}
+
+static int bpf_map_update_value(struct bpf_map *map, struct fd f, void *key,
+				void *value, __u64 flags)
+{
+	int err;
+
+	/* Need to create a kthread, thus must support schedule */
+	if (bpf_map_is_dev_bound(map)) {
+		return bpf_map_offload_update_elem(map, key, value, flags);
+	} else if (map->map_type == BPF_MAP_TYPE_CPUMAP ||
+		   map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
+		return map->ops->map_update_elem(map, key, value, flags);
+	} else if (map->map_type == BPF_MAP_TYPE_SOCKHASH ||
+		   map->map_type == BPF_MAP_TYPE_SOCKMAP) {
+		return sock_map_update_elem_sys(map, key, value, flags);
+	} else if (IS_FD_PROG_ARRAY(map)) {
+		return bpf_fd_array_map_update_elem(map, f.file, key, value,
+						    flags);
+	}
+
+	bpf_disable_instrumentation();
+	if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+	    map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
+		err = bpf_percpu_hash_update(map, key, value, flags);
+	} else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
+		err = bpf_percpu_array_update(map, key, value, flags);
+	} else if (map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) {
+		err = bpf_percpu_cgroup_storage_update(map, key, value,
+						       flags);
+	} else if (IS_FD_ARRAY(map)) {
+		rcu_read_lock();
+		err = bpf_fd_array_map_update_elem(map, f.file, key, value,
+						   flags);
+		rcu_read_unlock();
+	} else if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
+		rcu_read_lock();
+		err = bpf_fd_htab_map_update_elem(map, f.file, key, value,
+						  flags);
+		rcu_read_unlock();
+	} else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) {
+		/* rcu_read_lock() is not needed */
+		err = bpf_fd_reuseport_array_update_elem(map, key, value,
+							 flags);
+	} else if (map->map_type == BPF_MAP_TYPE_QUEUE ||
+		   map->map_type == BPF_MAP_TYPE_STACK ||
+		   map->map_type == BPF_MAP_TYPE_BLOOM_FILTER) {
+		err = map->ops->map_push_elem(map, value, flags);
+	} else {
+		rcu_read_lock();
+		err = map->ops->map_update_elem(map, key, value, flags);
+		rcu_read_unlock();
+	}
+	bpf_enable_instrumentation();
+	maybe_wait_bpf_programs(map);
+
+	return err;
+}
+
+static int bpf_map_copy_value(struct bpf_map *map, void *key, void *value,
+			      __u64 flags)
+{
+	void *ptr;
+	int err;
+
+	if (bpf_map_is_dev_bound(map))
+		return bpf_map_offload_lookup_elem(map, key, value);
+
+	bpf_disable_instrumentation();
+	if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+	    map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
+		err = bpf_percpu_hash_copy(map, key, value);
+	} else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
+		err = bpf_percpu_array_copy(map, key, value);
+	} else if (map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) {
+		err = bpf_percpu_cgroup_storage_copy(map, key, value);
+	} else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) {
+		err = bpf_stackmap_copy(map, key, value);
+	} else if (IS_FD_ARRAY(map) || IS_FD_PROG_ARRAY(map)) {
+		err = bpf_fd_array_map_lookup_elem(map, key, value);
+	} else if (IS_FD_HASH(map)) {
+		err = bpf_fd_htab_map_lookup_elem(map, key, value);
+	} else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) {
+		err = bpf_fd_reuseport_array_lookup_elem(map, key, value);
+	} else if (map->map_type == BPF_MAP_TYPE_QUEUE ||
+		   map->map_type == BPF_MAP_TYPE_STACK ||
+		   map->map_type == BPF_MAP_TYPE_BLOOM_FILTER) {
+		err = map->ops->map_peek_elem(map, value);
+	} else if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
+		/* struct_ops map requires directly updating "value" */
+		err = bpf_struct_ops_map_sys_lookup_elem(map, key, value);
+	} else {
+		rcu_read_lock();
+		if (map->ops->map_lookup_elem_sys_only)
+			ptr = map->ops->map_lookup_elem_sys_only(map, key);
+		else
+			ptr = map->ops->map_lookup_elem(map, key);
+		if (IS_ERR(ptr)) {
+			err = PTR_ERR(ptr);
+		} else if (!ptr) {
+			err = -ENOENT;
+		} else {
+			err = 0;
+			if (flags & BPF_F_LOCK)
+				/* lock 'ptr' and copy everything but lock */
+				copy_map_value_locked(map, value, ptr, true);
+			else
+				copy_map_value(map, value, ptr);
+			/* mask lock and timer, since value wasn't zero inited */
+			check_and_init_map_value(map, value);
+		}
+		rcu_read_unlock();
+	}
+
+	bpf_enable_instrumentation();
+	maybe_wait_bpf_programs(map);
+
+	return err;
+}
+
+/* Please, do not use this function outside from the map creation path
+ * (e.g. in map update path) without taking care of setting the active
+ * memory cgroup (see at bpf_map_kmalloc_node() for example).
+ */
+static void *__bpf_map_area_alloc(u64 size, int numa_node, bool mmapable)
+{
+	/* We really just want to fail instead of triggering OOM killer
+	 * under memory pressure, therefore we set __GFP_NORETRY to kmalloc,
+	 * which is used for lower order allocation requests.
+	 *
+	 * It has been observed that higher order allocation requests done by
+	 * vmalloc with __GFP_NORETRY being set might fail due to not trying
+	 * to reclaim memory from the page cache, thus we set
+	 * __GFP_RETRY_MAYFAIL to avoid such situations.
+	 */
+
+	const gfp_t gfp = __GFP_NOWARN | __GFP_ZERO | __GFP_ACCOUNT;
+	unsigned int flags = 0;
+	unsigned long align = 1;
+	void *area;
+
+	if (size >= SIZE_MAX)
+		return NULL;
+
+	/* kmalloc()'ed memory can't be mmap()'ed */
+	if (mmapable) {
+		BUG_ON(!PAGE_ALIGNED(size));
+		align = SHMLBA;
+		flags = VM_USERMAP;
+	} else if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
+		area = kmalloc_node(size, gfp | GFP_USER | __GFP_NORETRY,
+				    numa_node);
+		if (area != NULL)
+			return area;
+	}
+
+	return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END,
+			gfp | GFP_KERNEL | __GFP_RETRY_MAYFAIL, PAGE_KERNEL,
+			flags, numa_node, __builtin_return_address(0));
+}
+
+void *bpf_map_area_alloc(u64 size, int numa_node)
+{
+	return __bpf_map_area_alloc(size, numa_node, false);
+}
+
+void *bpf_map_area_mmapable_alloc(u64 size, int numa_node)
+{
+	return __bpf_map_area_alloc(size, numa_node, true);
+}
+
+void bpf_map_area_free(void *area)
+{
+	kvfree(area);
+}
+
+static u32 bpf_map_flags_retain_permanent(u32 flags)
+{
+	/* Some map creation flags are not tied to the map object but
+	 * rather to the map fd instead, so they have no meaning upon
+	 * map object inspection since multiple file descriptors with
+	 * different (access) properties can exist here. Thus, given
+	 * this has zero meaning for the map itself, lets clear these
+	 * from here.
+	 */
+	return flags & ~(BPF_F_RDONLY | BPF_F_WRONLY);
+}
+
+void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr)
+{
+	map->map_type = attr->map_type;
+	map->key_size = attr->key_size;
+	map->value_size = attr->value_size;
+	map->max_entries = attr->max_entries;
+	map->map_flags = bpf_map_flags_retain_permanent(attr->map_flags);
+	map->numa_node = bpf_map_attr_numa_node(attr);
+	map->map_extra = attr->map_extra;
+}
+
+static int bpf_map_alloc_id(struct bpf_map *map)
+{
+	int id;
+
+	idr_preload(GFP_KERNEL);
+	spin_lock_bh(&map_idr_lock);
+	id = idr_alloc_cyclic(&map_idr, map, 1, INT_MAX, GFP_ATOMIC);
+	if (id > 0)
+		map->id = id;
+	spin_unlock_bh(&map_idr_lock);
+	idr_preload_end();
+
+	if (WARN_ON_ONCE(!id))
+		return -ENOSPC;
+
+	return id > 0 ? 0 : id;
+}
+
+void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock)
+{
+	unsigned long flags;
+
+	/* Offloaded maps are removed from the IDR store when their device
+	 * disappears - even if someone holds an fd to them they are unusable,
+	 * the memory is gone, all ops will fail; they are simply waiting for
+	 * refcnt to drop to be freed.
+	 */
+	if (!map->id)
+		return;
+
+	if (do_idr_lock)
+		spin_lock_irqsave(&map_idr_lock, flags);
+	else
+		__acquire(&map_idr_lock);
+
+	idr_remove(&map_idr, map->id);
+	map->id = 0;
+
+	if (do_idr_lock)
+		spin_unlock_irqrestore(&map_idr_lock, flags);
+	else
+		__release(&map_idr_lock);
+}
+
+#ifdef CONFIG_MEMCG_KMEM
+static void bpf_map_save_memcg(struct bpf_map *map)
+{
+	/* Currently if a map is created by a process belonging to the root
+	 * memory cgroup, get_obj_cgroup_from_current() will return NULL.
+	 * So we have to check map->objcg for being NULL each time it's
+	 * being used.
+	 */
+	map->objcg = get_obj_cgroup_from_current();
+}
+
+static void bpf_map_release_memcg(struct bpf_map *map)
+{
+	if (map->objcg)
+		obj_cgroup_put(map->objcg);
+}
+
+static struct mem_cgroup *bpf_map_get_memcg(const struct bpf_map *map)
+{
+	if (map->objcg)
+		return get_mem_cgroup_from_objcg(map->objcg);
+
+	return root_mem_cgroup;
+}
+
+void *bpf_map_kmalloc_node(const struct bpf_map *map, size_t size, gfp_t flags,
+			   int node)
+{
+	struct mem_cgroup *memcg, *old_memcg;
+	void *ptr;
+
+	memcg = bpf_map_get_memcg(map);
+	old_memcg = set_active_memcg(memcg);
+	ptr = kmalloc_node(size, flags | __GFP_ACCOUNT, node);
+	set_active_memcg(old_memcg);
+	mem_cgroup_put(memcg);
+
+	return ptr;
+}
+
+void *bpf_map_kzalloc(const struct bpf_map *map, size_t size, gfp_t flags)
+{
+	struct mem_cgroup *memcg, *old_memcg;
+	void *ptr;
+
+	memcg = bpf_map_get_memcg(map);
+	old_memcg = set_active_memcg(memcg);
+	ptr = kzalloc(size, flags | __GFP_ACCOUNT);
+	set_active_memcg(old_memcg);
+	mem_cgroup_put(memcg);
+
+	return ptr;
+}
+
+void __percpu *bpf_map_alloc_percpu(const struct bpf_map *map, size_t size,
+				    size_t align, gfp_t flags)
+{
+	struct mem_cgroup *memcg, *old_memcg;
+	void __percpu *ptr;
+
+	memcg = bpf_map_get_memcg(map);
+	old_memcg = set_active_memcg(memcg);
+	ptr = __alloc_percpu_gfp(size, align, flags | __GFP_ACCOUNT);
+	set_active_memcg(old_memcg);
+	mem_cgroup_put(memcg);
+
+	return ptr;
+}
+
+#else
+static void bpf_map_save_memcg(struct bpf_map *map)
+{
+}
+
+static void bpf_map_release_memcg(struct bpf_map *map)
+{
+}
+#endif
+
+static int bpf_map_kptr_off_cmp(const void *a, const void *b)
+{
+	const struct bpf_map_value_off_desc *off_desc1 = a, *off_desc2 = b;
+
+	if (off_desc1->offset < off_desc2->offset)
+		return -1;
+	else if (off_desc1->offset > off_desc2->offset)
+		return 1;
+	return 0;
+}
+
+struct bpf_map_value_off_desc *bpf_map_kptr_off_contains(struct bpf_map *map, u32 offset)
+{
+	/* Since members are iterated in btf_find_field in increasing order,
+	 * offsets appended to kptr_off_tab are in increasing order, so we can
+	 * do bsearch to find exact match.
+	 */
+	struct bpf_map_value_off *tab;
+
+	if (!map_value_has_kptrs(map))
+		return NULL;
+	tab = map->kptr_off_tab;
+	return bsearch(&offset, tab->off, tab->nr_off, sizeof(tab->off[0]), bpf_map_kptr_off_cmp);
+}
+
+void bpf_map_free_kptr_off_tab(struct bpf_map *map)
+{
+	struct bpf_map_value_off *tab = map->kptr_off_tab;
+	int i;
+
+	if (!map_value_has_kptrs(map))
+		return;
+	for (i = 0; i < tab->nr_off; i++) {
+		if (tab->off[i].kptr.module)
+			module_put(tab->off[i].kptr.module);
+		btf_put(tab->off[i].kptr.btf);
+	}
+	kfree(tab);
+	map->kptr_off_tab = NULL;
+}
+
+struct bpf_map_value_off *bpf_map_copy_kptr_off_tab(const struct bpf_map *map)
+{
+	struct bpf_map_value_off *tab = map->kptr_off_tab, *new_tab;
+	int size, i;
+
+	if (!map_value_has_kptrs(map))
+		return ERR_PTR(-ENOENT);
+	size = offsetof(struct bpf_map_value_off, off[tab->nr_off]);
+	new_tab = kmemdup(tab, size, GFP_KERNEL | __GFP_NOWARN);
+	if (!new_tab)
+		return ERR_PTR(-ENOMEM);
+	/* Do a deep copy of the kptr_off_tab */
+	for (i = 0; i < tab->nr_off; i++) {
+		btf_get(tab->off[i].kptr.btf);
+		if (tab->off[i].kptr.module && !try_module_get(tab->off[i].kptr.module)) {
+			while (i--) {
+				if (tab->off[i].kptr.module)
+					module_put(tab->off[i].kptr.module);
+				btf_put(tab->off[i].kptr.btf);
+			}
+			kfree(new_tab);
+			return ERR_PTR(-ENXIO);
+		}
+	}
+	return new_tab;
+}
+
+bool bpf_map_equal_kptr_off_tab(const struct bpf_map *map_a, const struct bpf_map *map_b)
+{
+	struct bpf_map_value_off *tab_a = map_a->kptr_off_tab, *tab_b = map_b->kptr_off_tab;
+	bool a_has_kptr = map_value_has_kptrs(map_a), b_has_kptr = map_value_has_kptrs(map_b);
+	int size;
+
+	if (!a_has_kptr && !b_has_kptr)
+		return true;
+	if (a_has_kptr != b_has_kptr)
+		return false;
+	if (tab_a->nr_off != tab_b->nr_off)
+		return false;
+	size = offsetof(struct bpf_map_value_off, off[tab_a->nr_off]);
+	return !memcmp(tab_a, tab_b, size);
+}
+
+/* Caller must ensure map_value_has_kptrs is true. Note that this function can
+ * be called on a map value while the map_value is visible to BPF programs, as
+ * it ensures the correct synchronization, and we already enforce the same using
+ * the bpf_kptr_xchg helper on the BPF program side for referenced kptrs.
+ */
+void bpf_map_free_kptrs(struct bpf_map *map, void *map_value)
+{
+	struct bpf_map_value_off *tab = map->kptr_off_tab;
+	unsigned long *btf_id_ptr;
+	int i;
+
+	for (i = 0; i < tab->nr_off; i++) {
+		struct bpf_map_value_off_desc *off_desc = &tab->off[i];
+		unsigned long old_ptr;
+
+		btf_id_ptr = map_value + off_desc->offset;
+		if (off_desc->type == BPF_KPTR_UNREF) {
+			u64 *p = (u64 *)btf_id_ptr;
+
+			WRITE_ONCE(*p, 0);
+			continue;
+		}
+		old_ptr = xchg(btf_id_ptr, 0);
+		off_desc->kptr.dtor((void *)old_ptr);
+	}
+}
+
+/* called from workqueue */
+static void bpf_map_free_deferred(struct work_struct *work)
+{
+	struct bpf_map *map = container_of(work, struct bpf_map, work);
+
+	security_bpf_map_free(map);
+	kfree(map->off_arr);
+	bpf_map_release_memcg(map);
+	/* implementation dependent freeing, map_free callback also does
+	 * bpf_map_free_kptr_off_tab, if needed.
+	 */
+	map->ops->map_free(map);
+}
+
+static void bpf_map_put_uref(struct bpf_map *map)
+{
+	if (atomic64_dec_and_test(&map->usercnt)) {
+		if (map->ops->map_release_uref)
+			map->ops->map_release_uref(map);
+	}
+}
+
+static void bpf_map_free_in_work(struct bpf_map *map)
+{
+	INIT_WORK(&map->work, bpf_map_free_deferred);
+	/* Avoid spawning kworkers, since they all might contend
+	 * for the same mutex like slab_mutex.
+	 */
+	queue_work(system_unbound_wq, &map->work);
+}
+
+static void bpf_map_free_rcu_gp(struct rcu_head *rcu)
+{
+	bpf_map_free_in_work(container_of(rcu, struct bpf_map, rcu));
+}
+
+static void bpf_map_free_mult_rcu_gp(struct rcu_head *rcu)
+{
+	if (rcu_trace_implies_rcu_gp())
+		bpf_map_free_rcu_gp(rcu);
+	else
+		call_rcu(rcu, bpf_map_free_rcu_gp);
+}
+
+/* decrement map refcnt and schedule it for freeing via workqueue
+ * (unrelying map implementation ops->map_free() might sleep)
+ */
+static void __bpf_map_put(struct bpf_map *map, bool do_idr_lock)
+{
+	if (atomic64_dec_and_test(&map->refcnt)) {
+		/* bpf_map_free_id() must be called first */
+		bpf_map_free_id(map, do_idr_lock);
+		btf_put(map->btf);
+
+		if (READ_ONCE(map->free_after_mult_rcu_gp))
+			call_rcu_tasks_trace(&map->rcu, bpf_map_free_mult_rcu_gp);
+		else
+			bpf_map_free_in_work(map);
+	}
+}
+
+void bpf_map_put(struct bpf_map *map)
+{
+	__bpf_map_put(map, true);
+}
+EXPORT_SYMBOL_GPL(bpf_map_put);
+
+void bpf_map_put_with_uref(struct bpf_map *map)
+{
+	bpf_map_put_uref(map);
+	bpf_map_put(map);
+}
+
+static int bpf_map_release(struct inode *inode, struct file *filp)
+{
+	struct bpf_map *map = filp->private_data;
+
+	if (map->ops->map_release)
+		map->ops->map_release(map, filp);
+
+	bpf_map_put_with_uref(map);
+	return 0;
+}
+
+static fmode_t map_get_sys_perms(struct bpf_map *map, struct fd f)
+{
+	fmode_t mode = f.file->f_mode;
+
+	/* Our file permissions may have been overridden by global
+	 * map permissions facing syscall side.
+	 */
+	if (READ_ONCE(map->frozen))
+		mode &= ~FMODE_CAN_WRITE;
+	return mode;
+}
+
+#ifdef CONFIG_PROC_FS
+/* Provides an approximation of the map's memory footprint.
+ * Used only to provide a backward compatibility and display
+ * a reasonable "memlock" info.
+ */
+static unsigned long bpf_map_memory_footprint(const struct bpf_map *map)
+{
+	unsigned long size;
+
+	size = round_up(map->key_size + bpf_map_value_size(map), 8);
+
+	return round_up(map->max_entries * size, PAGE_SIZE);
+}
+
+static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
+{
+	struct bpf_map *map = filp->private_data;
+	u32 type = 0, jited = 0;
+
+	if (map_type_contains_progs(map)) {
+		spin_lock(&map->owner.lock);
+		type  = map->owner.type;
+		jited = map->owner.jited;
+		spin_unlock(&map->owner.lock);
+	}
+
+	seq_printf(m,
+		   "map_type:\t%u\n"
+		   "key_size:\t%u\n"
+		   "value_size:\t%u\n"
+		   "max_entries:\t%u\n"
+		   "map_flags:\t%#x\n"
+		   "map_extra:\t%#llx\n"
+		   "memlock:\t%lu\n"
+		   "map_id:\t%u\n"
+		   "frozen:\t%u\n",
+		   map->map_type,
+		   map->key_size,
+		   map->value_size,
+		   map->max_entries,
+		   map->map_flags,
+		   (unsigned long long)map->map_extra,
+		   bpf_map_memory_footprint(map),
+		   map->id,
+		   READ_ONCE(map->frozen));
+	if (type) {
+		seq_printf(m, "owner_prog_type:\t%u\n", type);
+		seq_printf(m, "owner_jited:\t%u\n", jited);
+	}
+}
+#endif
+
+static ssize_t bpf_dummy_read(struct file *filp, char __user *buf, size_t siz,
+			      loff_t *ppos)
+{
+	/* We need this handler such that alloc_file() enables
+	 * f_mode with FMODE_CAN_READ.
+	 */
+	return -EINVAL;
+}
+
+static ssize_t bpf_dummy_write(struct file *filp, const char __user *buf,
+			       size_t siz, loff_t *ppos)
+{
+	/* We need this handler such that alloc_file() enables
+	 * f_mode with FMODE_CAN_WRITE.
+	 */
+	return -EINVAL;
+}
+
+/* called for any extra memory-mapped regions (except initial) */
+static void bpf_map_mmap_open(struct vm_area_struct *vma)
+{
+	struct bpf_map *map = vma->vm_file->private_data;
+
+	if (vma->vm_flags & VM_MAYWRITE)
+		bpf_map_write_active_inc(map);
+}
+
+/* called for all unmapped memory region (including initial) */
+static void bpf_map_mmap_close(struct vm_area_struct *vma)
+{
+	struct bpf_map *map = vma->vm_file->private_data;
+
+	if (vma->vm_flags & VM_MAYWRITE)
+		bpf_map_write_active_dec(map);
+}
+
+static const struct vm_operations_struct bpf_map_default_vmops = {
+	.open		= bpf_map_mmap_open,
+	.close		= bpf_map_mmap_close,
+};
+
+static int bpf_map_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	struct bpf_map *map = filp->private_data;
+	int err;
+
+	if (!map->ops->map_mmap || map_value_has_spin_lock(map) ||
+	    map_value_has_timer(map) || map_value_has_kptrs(map))
+		return -ENOTSUPP;
+
+	if (!(vma->vm_flags & VM_SHARED))
+		return -EINVAL;
+
+	mutex_lock(&map->freeze_mutex);
+
+	if (vma->vm_flags & VM_WRITE) {
+		if (map->frozen) {
+			err = -EPERM;
+			goto out;
+		}
+		/* map is meant to be read-only, so do not allow mapping as
+		 * writable, because it's possible to leak a writable page
+		 * reference and allows user-space to still modify it after
+		 * freezing, while verifier will assume contents do not change
+		 */
+		if (map->map_flags & BPF_F_RDONLY_PROG) {
+			err = -EACCES;
+			goto out;
+		}
+	}
+
+	/* set default open/close callbacks */
+	vma->vm_ops = &bpf_map_default_vmops;
+	vma->vm_private_data = map;
+	vma->vm_flags &= ~VM_MAYEXEC;
+	if (!(vma->vm_flags & VM_WRITE))
+		/* disallow re-mapping with PROT_WRITE */
+		vma->vm_flags &= ~VM_MAYWRITE;
+
+	err = map->ops->map_mmap(map, vma);
+	if (err)
+		goto out;
+
+	if (vma->vm_flags & VM_MAYWRITE)
+		bpf_map_write_active_inc(map);
+out:
+	mutex_unlock(&map->freeze_mutex);
+	return err;
+}
+
+static __poll_t bpf_map_poll(struct file *filp, struct poll_table_struct *pts)
+{
+	struct bpf_map *map = filp->private_data;
+
+	if (map->ops->map_poll)
+		return map->ops->map_poll(map, filp, pts);
+
+	return EPOLLERR;
+}
+
+const struct file_operations bpf_map_fops = {
+#ifdef CONFIG_PROC_FS
+	.show_fdinfo	= bpf_map_show_fdinfo,
+#endif
+	.release	= bpf_map_release,
+	.read		= bpf_dummy_read,
+	.write		= bpf_dummy_write,
+	.mmap		= bpf_map_mmap,
+	.poll		= bpf_map_poll,
+};
+
+int bpf_map_new_fd(struct bpf_map *map, int flags)
+{
+	int ret;
+
+	ret = security_bpf_map(map, OPEN_FMODE(flags));
+	if (ret < 0)
+		return ret;
+
+	return anon_inode_getfd("bpf-map", &bpf_map_fops, map,
+				flags | O_CLOEXEC);
+}
+
+int bpf_get_file_flag(int flags)
+{
+	if ((flags & BPF_F_RDONLY) && (flags & BPF_F_WRONLY))
+		return -EINVAL;
+	if (flags & BPF_F_RDONLY)
+		return O_RDONLY;
+	if (flags & BPF_F_WRONLY)
+		return O_WRONLY;
+	return O_RDWR;
+}
+
+/* helper macro to check that unused fields 'union bpf_attr' are zero */
+#define CHECK_ATTR(CMD) \
+	memchr_inv((void *) &attr->CMD##_LAST_FIELD + \
+		   sizeof(attr->CMD##_LAST_FIELD), 0, \
+		   sizeof(*attr) - \
+		   offsetof(union bpf_attr, CMD##_LAST_FIELD) - \
+		   sizeof(attr->CMD##_LAST_FIELD)) != NULL
+
+/* dst and src must have at least "size" number of bytes.
+ * Return strlen on success and < 0 on error.
+ */
+int bpf_obj_name_cpy(char *dst, const char *src, unsigned int size)
+{
+	const char *end = src + size;
+	const char *orig_src = src;
+
+	memset(dst, 0, size);
+	/* Copy all isalnum(), '_' and '.' chars. */
+	while (src < end && *src) {
+		if (!isalnum(*src) &&
+		    *src != '_' && *src != '.')
+			return -EINVAL;
+		*dst++ = *src++;
+	}
+
+	/* No '\0' found in "size" number of bytes */
+	if (src == end)
+		return -EINVAL;
+
+	return src - orig_src;
+}
+
+int map_check_no_btf(const struct bpf_map *map,
+		     const struct btf *btf,
+		     const struct btf_type *key_type,
+		     const struct btf_type *value_type)
+{
+	return -ENOTSUPP;
+}
+
+static int map_off_arr_cmp(const void *_a, const void *_b, const void *priv)
+{
+	const u32 a = *(const u32 *)_a;
+	const u32 b = *(const u32 *)_b;
+
+	if (a < b)
+		return -1;
+	else if (a > b)
+		return 1;
+	return 0;
+}
+
+static void map_off_arr_swap(void *_a, void *_b, int size, const void *priv)
+{
+	struct bpf_map *map = (struct bpf_map *)priv;
+	u32 *off_base = map->off_arr->field_off;
+	u32 *a = _a, *b = _b;
+	u8 *sz_a, *sz_b;
+
+	sz_a = map->off_arr->field_sz + (a - off_base);
+	sz_b = map->off_arr->field_sz + (b - off_base);
+
+	swap(*a, *b);
+	swap(*sz_a, *sz_b);
+}
+
+static int bpf_map_alloc_off_arr(struct bpf_map *map)
+{
+	bool has_spin_lock = map_value_has_spin_lock(map);
+	bool has_timer = map_value_has_timer(map);
+	bool has_kptrs = map_value_has_kptrs(map);
+	struct bpf_map_off_arr *off_arr;
+	u32 i;
+
+	if (!has_spin_lock && !has_timer && !has_kptrs) {
+		map->off_arr = NULL;
+		return 0;
+	}
+
+	off_arr = kmalloc(sizeof(*map->off_arr), GFP_KERNEL | __GFP_NOWARN);
+	if (!off_arr)
+		return -ENOMEM;
+	map->off_arr = off_arr;
+
+	off_arr->cnt = 0;
+	if (has_spin_lock) {
+		i = off_arr->cnt;
+
+		off_arr->field_off[i] = map->spin_lock_off;
+		off_arr->field_sz[i] = sizeof(struct bpf_spin_lock);
+		off_arr->cnt++;
+	}
+	if (has_timer) {
+		i = off_arr->cnt;
+
+		off_arr->field_off[i] = map->timer_off;
+		off_arr->field_sz[i] = sizeof(struct bpf_timer);
+		off_arr->cnt++;
+	}
+	if (has_kptrs) {
+		struct bpf_map_value_off *tab = map->kptr_off_tab;
+		u32 *off = &off_arr->field_off[off_arr->cnt];
+		u8 *sz = &off_arr->field_sz[off_arr->cnt];
+
+		for (i = 0; i < tab->nr_off; i++) {
+			*off++ = tab->off[i].offset;
+			*sz++ = sizeof(u64);
+		}
+		off_arr->cnt += tab->nr_off;
+	}
+
+	if (off_arr->cnt == 1)
+		return 0;
+	sort_r(off_arr->field_off, off_arr->cnt, sizeof(off_arr->field_off[0]),
+	       map_off_arr_cmp, map_off_arr_swap, map);
+	return 0;
+}
+
+static int map_check_btf(struct bpf_map *map, const struct btf *btf,
+			 u32 btf_key_id, u32 btf_value_id)
+{
+	const struct btf_type *key_type, *value_type;
+	u32 key_size, value_size;
+	int ret = 0;
+
+	/* Some maps allow key to be unspecified. */
+	if (btf_key_id) {
+		key_type = btf_type_id_size(btf, &btf_key_id, &key_size);
+		if (!key_type || key_size != map->key_size)
+			return -EINVAL;
+	} else {
+		key_type = btf_type_by_id(btf, 0);
+		if (!map->ops->map_check_btf)
+			return -EINVAL;
+	}
+
+	value_type = btf_type_id_size(btf, &btf_value_id, &value_size);
+	if (!value_type || value_size != map->value_size)
+		return -EINVAL;
+
+	map->spin_lock_off = btf_find_spin_lock(btf, value_type);
+
+	if (map_value_has_spin_lock(map)) {
+		if (map->map_flags & BPF_F_RDONLY_PROG)
+			return -EACCES;
+		if (map->map_type != BPF_MAP_TYPE_HASH &&
+		    map->map_type != BPF_MAP_TYPE_ARRAY &&
+		    map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
+		    map->map_type != BPF_MAP_TYPE_SK_STORAGE &&
+		    map->map_type != BPF_MAP_TYPE_INODE_STORAGE &&
+		    map->map_type != BPF_MAP_TYPE_TASK_STORAGE)
+			return -ENOTSUPP;
+		if (map->spin_lock_off + sizeof(struct bpf_spin_lock) >
+		    map->value_size) {
+			WARN_ONCE(1,
+				  "verifier bug spin_lock_off %d value_size %d\n",
+				  map->spin_lock_off, map->value_size);
+			return -EFAULT;
+		}
+	}
+
+	map->timer_off = btf_find_timer(btf, value_type);
+	if (map_value_has_timer(map)) {
+		if (map->map_flags & BPF_F_RDONLY_PROG)
+			return -EACCES;
+		if (map->map_type != BPF_MAP_TYPE_HASH &&
+		    map->map_type != BPF_MAP_TYPE_LRU_HASH &&
+		    map->map_type != BPF_MAP_TYPE_ARRAY)
+			return -EOPNOTSUPP;
+	}
+
+	map->kptr_off_tab = btf_parse_kptrs(btf, value_type);
+	if (map_value_has_kptrs(map)) {
+		if (!bpf_capable()) {
+			ret = -EPERM;
+			goto free_map_tab;
+		}
+		if (map->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG)) {
+			ret = -EACCES;
+			goto free_map_tab;
+		}
+		if (map->map_type != BPF_MAP_TYPE_HASH &&
+		    map->map_type != BPF_MAP_TYPE_LRU_HASH &&
+		    map->map_type != BPF_MAP_TYPE_ARRAY &&
+		    map->map_type != BPF_MAP_TYPE_PERCPU_ARRAY) {
+			ret = -EOPNOTSUPP;
+			goto free_map_tab;
+		}
+	}
+
+	if (map->ops->map_check_btf) {
+		ret = map->ops->map_check_btf(map, btf, key_type, value_type);
+		if (ret < 0)
+			goto free_map_tab;
+	}
+
+	return ret;
+free_map_tab:
+	bpf_map_free_kptr_off_tab(map);
+	return ret;
+}
+
+#define BPF_MAP_CREATE_LAST_FIELD map_extra
+/* called via syscall */
+static int map_create(union bpf_attr *attr)
+{
+	int numa_node = bpf_map_attr_numa_node(attr);
+	struct bpf_map *map;
+	int f_flags;
+	int err;
+
+	err = CHECK_ATTR(BPF_MAP_CREATE);
+	if (err)
+		return -EINVAL;
+
+	if (attr->btf_vmlinux_value_type_id) {
+		if (attr->map_type != BPF_MAP_TYPE_STRUCT_OPS ||
+		    attr->btf_key_type_id || attr->btf_value_type_id)
+			return -EINVAL;
+	} else if (attr->btf_key_type_id && !attr->btf_value_type_id) {
+		return -EINVAL;
+	}
+
+	if (attr->map_type != BPF_MAP_TYPE_BLOOM_FILTER &&
+	    attr->map_extra != 0)
+		return -EINVAL;
+
+	f_flags = bpf_get_file_flag(attr->map_flags);
+	if (f_flags < 0)
+		return f_flags;
+
+	if (numa_node != NUMA_NO_NODE &&
+	    ((unsigned int)numa_node >= nr_node_ids ||
+	     !node_online(numa_node)))
+		return -EINVAL;
+
+	/* find map type and init map: hashtable vs rbtree vs bloom vs ... */
+	map = find_and_alloc_map(attr);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+
+	err = bpf_obj_name_cpy(map->name, attr->map_name,
+			       sizeof(attr->map_name));
+	if (err < 0)
+		goto free_map;
+
+	atomic64_set(&map->refcnt, 1);
+	atomic64_set(&map->usercnt, 1);
+	mutex_init(&map->freeze_mutex);
+	spin_lock_init(&map->owner.lock);
+
+	map->spin_lock_off = -EINVAL;
+	map->timer_off = -EINVAL;
+	if (attr->btf_key_type_id || attr->btf_value_type_id ||
+	    /* Even the map's value is a kernel's struct,
+	     * the bpf_prog.o must have BTF to begin with
+	     * to figure out the corresponding kernel's
+	     * counter part.  Thus, attr->btf_fd has
+	     * to be valid also.
+	     */
+	    attr->btf_vmlinux_value_type_id) {
+		struct btf *btf;
+
+		btf = btf_get_by_fd(attr->btf_fd);
+		if (IS_ERR(btf)) {
+			err = PTR_ERR(btf);
+			goto free_map;
+		}
+		if (btf_is_kernel(btf)) {
+			btf_put(btf);
+			err = -EACCES;
+			goto free_map;
+		}
+		map->btf = btf;
+
+		if (attr->btf_value_type_id) {
+			err = map_check_btf(map, btf, attr->btf_key_type_id,
+					    attr->btf_value_type_id);
+			if (err)
+				goto free_map;
+		}
+
+		map->btf_key_type_id = attr->btf_key_type_id;
+		map->btf_value_type_id = attr->btf_value_type_id;
+		map->btf_vmlinux_value_type_id =
+			attr->btf_vmlinux_value_type_id;
+	}
+
+	err = bpf_map_alloc_off_arr(map);
+	if (err)
+		goto free_map;
+
+	err = security_bpf_map_alloc(map);
+	if (err)
+		goto free_map_off_arr;
+
+	err = bpf_map_alloc_id(map);
+	if (err)
+		goto free_map_sec;
+
+	bpf_map_save_memcg(map);
+
+	err = bpf_map_new_fd(map, f_flags);
+	if (err < 0) {
+		/* failed to allocate fd.
+		 * bpf_map_put_with_uref() is needed because the above
+		 * bpf_map_alloc_id() has published the map
+		 * to the userspace and the userspace may
+		 * have refcnt-ed it through BPF_MAP_GET_FD_BY_ID.
+		 */
+		bpf_map_put_with_uref(map);
+		return err;
+	}
+
+	return err;
+
+free_map_sec:
+	security_bpf_map_free(map);
+free_map_off_arr:
+	kfree(map->off_arr);
+free_map:
+	btf_put(map->btf);
+	map->ops->map_free(map);
+	return err;
+}
+
+/* if error is returned, fd is released.
+ * On success caller should complete fd access with matching fdput()
+ */
+struct bpf_map *__bpf_map_get(struct fd f)
+{
+	if (!f.file)
+		return ERR_PTR(-EBADF);
+	if (f.file->f_op != &bpf_map_fops) {
+		fdput(f);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return f.file->private_data;
+}
+
+void bpf_map_inc(struct bpf_map *map)
+{
+	atomic64_inc(&map->refcnt);
+}
+EXPORT_SYMBOL_GPL(bpf_map_inc);
+
+void bpf_map_inc_with_uref(struct bpf_map *map)
+{
+	atomic64_inc(&map->refcnt);
+	atomic64_inc(&map->usercnt);
+}
+EXPORT_SYMBOL_GPL(bpf_map_inc_with_uref);
+
+struct bpf_map *bpf_map_get(u32 ufd)
+{
+	struct fd f = fdget(ufd);
+	struct bpf_map *map;
+
+	map = __bpf_map_get(f);
+	if (IS_ERR(map))
+		return map;
+
+	bpf_map_inc(map);
+	fdput(f);
+
+	return map;
+}
+EXPORT_SYMBOL(bpf_map_get);
+
+struct bpf_map *bpf_map_get_with_uref(u32 ufd)
+{
+	struct fd f = fdget(ufd);
+	struct bpf_map *map;
+
+	map = __bpf_map_get(f);
+	if (IS_ERR(map))
+		return map;
+
+	bpf_map_inc_with_uref(map);
+	fdput(f);
+
+	return map;
+}
+
+/* map_idr_lock should have been held */
+static struct bpf_map *__bpf_map_inc_not_zero(struct bpf_map *map, bool uref)
+{
+	int refold;
+
+	refold = atomic64_fetch_add_unless(&map->refcnt, 1, 0);
+	if (!refold)
+		return ERR_PTR(-ENOENT);
+	if (uref)
+		atomic64_inc(&map->usercnt);
+
+	return map;
+}
+
+struct bpf_map *bpf_map_inc_not_zero(struct bpf_map *map)
+{
+	spin_lock_bh(&map_idr_lock);
+	map = __bpf_map_inc_not_zero(map, false);
+	spin_unlock_bh(&map_idr_lock);
+
+	return map;
+}
+EXPORT_SYMBOL_GPL(bpf_map_inc_not_zero);
+
+int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
+{
+	return -ENOTSUPP;
+}
+
+static void *__bpf_copy_key(void __user *ukey, u64 key_size)
+{
+	if (key_size)
+		return vmemdup_user(ukey, key_size);
+
+	if (ukey)
+		return ERR_PTR(-EINVAL);
+
+	return NULL;
+}
+
+static void *___bpf_copy_key(bpfptr_t ukey, u64 key_size)
+{
+	if (key_size)
+		return kvmemdup_bpfptr(ukey, key_size);
+
+	if (!bpfptr_is_null(ukey))
+		return ERR_PTR(-EINVAL);
+
+	return NULL;
+}
+
+/* last field in 'union bpf_attr' used by this command */
+#define BPF_MAP_LOOKUP_ELEM_LAST_FIELD flags
+
+static int map_lookup_elem(union bpf_attr *attr)
+{
+	void __user *ukey = u64_to_user_ptr(attr->key);
+	void __user *uvalue = u64_to_user_ptr(attr->value);
+	int ufd = attr->map_fd;
+	struct bpf_map *map;
+	void *key, *value;
+	u32 value_size;
+	struct fd f;
+	int err;
+
+	if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM))
+		return -EINVAL;
+
+	if (attr->flags & ~BPF_F_LOCK)
+		return -EINVAL;
+
+	f = fdget(ufd);
+	map = __bpf_map_get(f);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+	if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ)) {
+		err = -EPERM;
+		goto err_put;
+	}
+
+	if ((attr->flags & BPF_F_LOCK) &&
+	    !map_value_has_spin_lock(map)) {
+		err = -EINVAL;
+		goto err_put;
+	}
+
+	key = __bpf_copy_key(ukey, map->key_size);
+	if (IS_ERR(key)) {
+		err = PTR_ERR(key);
+		goto err_put;
+	}
+
+	value_size = bpf_map_value_size(map);
+
+	err = -ENOMEM;
+	value = kvmalloc(value_size, GFP_USER | __GFP_NOWARN);
+	if (!value)
+		goto free_key;
+
+	if (map->map_type == BPF_MAP_TYPE_BLOOM_FILTER) {
+		if (copy_from_user(value, uvalue, value_size))
+			err = -EFAULT;
+		else
+			err = bpf_map_copy_value(map, key, value, attr->flags);
+		goto free_value;
+	}
+
+	err = bpf_map_copy_value(map, key, value, attr->flags);
+	if (err)
+		goto free_value;
+
+	err = -EFAULT;
+	if (copy_to_user(uvalue, value, value_size) != 0)
+		goto free_value;
+
+	err = 0;
+
+free_value:
+	kvfree(value);
+free_key:
+	kvfree(key);
+err_put:
+	fdput(f);
+	return err;
+}
+
+
+#define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags
+
+static int map_update_elem(union bpf_attr *attr, bpfptr_t uattr)
+{
+	bpfptr_t ukey = make_bpfptr(attr->key, uattr.is_kernel);
+	bpfptr_t uvalue = make_bpfptr(attr->value, uattr.is_kernel);
+	int ufd = attr->map_fd;
+	struct bpf_map *map;
+	void *key, *value;
+	u32 value_size;
+	struct fd f;
+	int err;
+
+	if (CHECK_ATTR(BPF_MAP_UPDATE_ELEM))
+		return -EINVAL;
+
+	f = fdget(ufd);
+	map = __bpf_map_get(f);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+	bpf_map_write_active_inc(map);
+	if (!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
+		err = -EPERM;
+		goto err_put;
+	}
+
+	if ((attr->flags & BPF_F_LOCK) &&
+	    !map_value_has_spin_lock(map)) {
+		err = -EINVAL;
+		goto err_put;
+	}
+
+	key = ___bpf_copy_key(ukey, map->key_size);
+	if (IS_ERR(key)) {
+		err = PTR_ERR(key);
+		goto err_put;
+	}
+
+	value_size = bpf_map_value_size(map);
+	value = kvmemdup_bpfptr(uvalue, value_size);
+	if (IS_ERR(value)) {
+		err = PTR_ERR(value);
+		goto free_key;
+	}
+
+	err = bpf_map_update_value(map, f, key, value, attr->flags);
+
+	kvfree(value);
+free_key:
+	kvfree(key);
+err_put:
+	bpf_map_write_active_dec(map);
+	fdput(f);
+	return err;
+}
+
+#define BPF_MAP_DELETE_ELEM_LAST_FIELD key
+
+static int map_delete_elem(union bpf_attr *attr, bpfptr_t uattr)
+{
+	bpfptr_t ukey = make_bpfptr(attr->key, uattr.is_kernel);
+	int ufd = attr->map_fd;
+	struct bpf_map *map;
+	struct fd f;
+	void *key;
+	int err;
+
+	if (CHECK_ATTR(BPF_MAP_DELETE_ELEM))
+		return -EINVAL;
+
+	f = fdget(ufd);
+	map = __bpf_map_get(f);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+	bpf_map_write_active_inc(map);
+	if (!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
+		err = -EPERM;
+		goto err_put;
+	}
+
+	key = ___bpf_copy_key(ukey, map->key_size);
+	if (IS_ERR(key)) {
+		err = PTR_ERR(key);
+		goto err_put;
+	}
+
+	if (bpf_map_is_dev_bound(map)) {
+		err = bpf_map_offload_delete_elem(map, key);
+		goto out;
+	} else if (IS_FD_PROG_ARRAY(map) ||
+		   map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
+		/* These maps require sleepable context */
+		err = map->ops->map_delete_elem(map, key);
+		goto out;
+	}
+
+	bpf_disable_instrumentation();
+	rcu_read_lock();
+	err = map->ops->map_delete_elem(map, key);
+	rcu_read_unlock();
+	bpf_enable_instrumentation();
+	maybe_wait_bpf_programs(map);
+out:
+	kvfree(key);
+err_put:
+	bpf_map_write_active_dec(map);
+	fdput(f);
+	return err;
+}
+
+/* last field in 'union bpf_attr' used by this command */
+#define BPF_MAP_GET_NEXT_KEY_LAST_FIELD next_key
+
+static int map_get_next_key(union bpf_attr *attr)
+{
+	void __user *ukey = u64_to_user_ptr(attr->key);
+	void __user *unext_key = u64_to_user_ptr(attr->next_key);
+	int ufd = attr->map_fd;
+	struct bpf_map *map;
+	void *key, *next_key;
+	struct fd f;
+	int err;
+
+	if (CHECK_ATTR(BPF_MAP_GET_NEXT_KEY))
+		return -EINVAL;
+
+	f = fdget(ufd);
+	map = __bpf_map_get(f);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+	if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ)) {
+		err = -EPERM;
+		goto err_put;
+	}
+
+	if (ukey) {
+		key = __bpf_copy_key(ukey, map->key_size);
+		if (IS_ERR(key)) {
+			err = PTR_ERR(key);
+			goto err_put;
+		}
+	} else {
+		key = NULL;
+	}
+
+	err = -ENOMEM;
+	next_key = kvmalloc(map->key_size, GFP_USER);
+	if (!next_key)
+		goto free_key;
+
+	if (bpf_map_is_dev_bound(map)) {
+		err = bpf_map_offload_get_next_key(map, key, next_key);
+		goto out;
+	}
+
+	rcu_read_lock();
+	err = map->ops->map_get_next_key(map, key, next_key);
+	rcu_read_unlock();
+out:
+	if (err)
+		goto free_next_key;
+
+	err = -EFAULT;
+	if (copy_to_user(unext_key, next_key, map->key_size) != 0)
+		goto free_next_key;
+
+	err = 0;
+
+free_next_key:
+	kvfree(next_key);
+free_key:
+	kvfree(key);
+err_put:
+	fdput(f);
+	return err;
+}
+
+int generic_map_delete_batch(struct bpf_map *map,
+			     const union bpf_attr *attr,
+			     union bpf_attr __user *uattr)
+{
+	void __user *keys = u64_to_user_ptr(attr->batch.keys);
+	u32 cp, max_count;
+	int err = 0;
+	void *key;
+
+	if (attr->batch.elem_flags & ~BPF_F_LOCK)
+		return -EINVAL;
+
+	if ((attr->batch.elem_flags & BPF_F_LOCK) &&
+	    !map_value_has_spin_lock(map)) {
+		return -EINVAL;
+	}
+
+	max_count = attr->batch.count;
+	if (!max_count)
+		return 0;
+
+	key = kvmalloc(map->key_size, GFP_USER | __GFP_NOWARN);
+	if (!key)
+		return -ENOMEM;
+
+	for (cp = 0; cp < max_count; cp++) {
+		err = -EFAULT;
+		if (copy_from_user(key, keys + cp * map->key_size,
+				   map->key_size))
+			break;
+
+		if (bpf_map_is_dev_bound(map)) {
+			err = bpf_map_offload_delete_elem(map, key);
+			break;
+		}
+
+		bpf_disable_instrumentation();
+		rcu_read_lock();
+		err = map->ops->map_delete_elem(map, key);
+		rcu_read_unlock();
+		bpf_enable_instrumentation();
+		if (err)
+			break;
+		cond_resched();
+	}
+	if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp)))
+		err = -EFAULT;
+
+	kvfree(key);
+
+	maybe_wait_bpf_programs(map);
+	return err;
+}
+
+int generic_map_update_batch(struct bpf_map *map,
+			     const union bpf_attr *attr,
+			     union bpf_attr __user *uattr)
+{
+	void __user *values = u64_to_user_ptr(attr->batch.values);
+	void __user *keys = u64_to_user_ptr(attr->batch.keys);
+	u32 value_size, cp, max_count;
+	int ufd = attr->batch.map_fd;
+	void *key, *value;
+	struct fd f;
+	int err = 0;
+
+	if (attr->batch.elem_flags & ~BPF_F_LOCK)
+		return -EINVAL;
+
+	if ((attr->batch.elem_flags & BPF_F_LOCK) &&
+	    !map_value_has_spin_lock(map)) {
+		return -EINVAL;
+	}
+
+	value_size = bpf_map_value_size(map);
+
+	max_count = attr->batch.count;
+	if (!max_count)
+		return 0;
+
+	key = kvmalloc(map->key_size, GFP_USER | __GFP_NOWARN);
+	if (!key)
+		return -ENOMEM;
+
+	value = kvmalloc(value_size, GFP_USER | __GFP_NOWARN);
+	if (!value) {
+		kvfree(key);
+		return -ENOMEM;
+	}
+
+	f = fdget(ufd); /* bpf_map_do_batch() guarantees ufd is valid */
+	for (cp = 0; cp < max_count; cp++) {
+		err = -EFAULT;
+		if (copy_from_user(key, keys + cp * map->key_size,
+		    map->key_size) ||
+		    copy_from_user(value, values + cp * value_size, value_size))
+			break;
+
+		err = bpf_map_update_value(map, f, key, value,
+					   attr->batch.elem_flags);
+
+		if (err)
+			break;
+		cond_resched();
+	}
+
+	if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp)))
+		err = -EFAULT;
+
+	kvfree(value);
+	kvfree(key);
+	fdput(f);
+	return err;
+}
+
+#define MAP_LOOKUP_RETRIES 3
+
+int generic_map_lookup_batch(struct bpf_map *map,
+				    const union bpf_attr *attr,
+				    union bpf_attr __user *uattr)
+{
+	void __user *uobatch = u64_to_user_ptr(attr->batch.out_batch);
+	void __user *ubatch = u64_to_user_ptr(attr->batch.in_batch);
+	void __user *values = u64_to_user_ptr(attr->batch.values);
+	void __user *keys = u64_to_user_ptr(attr->batch.keys);
+	void *buf, *buf_prevkey, *prev_key, *key, *value;
+	int err, retry = MAP_LOOKUP_RETRIES;
+	u32 value_size, cp, max_count;
+
+	if (attr->batch.elem_flags & ~BPF_F_LOCK)
+		return -EINVAL;
+
+	if ((attr->batch.elem_flags & BPF_F_LOCK) &&
+	    !map_value_has_spin_lock(map))
+		return -EINVAL;
+
+	value_size = bpf_map_value_size(map);
+
+	max_count = attr->batch.count;
+	if (!max_count)
+		return 0;
+
+	if (put_user(0, &uattr->batch.count))
+		return -EFAULT;
+
+	buf_prevkey = kvmalloc(map->key_size, GFP_USER | __GFP_NOWARN);
+	if (!buf_prevkey)
+		return -ENOMEM;
+
+	buf = kvmalloc(map->key_size + value_size, GFP_USER | __GFP_NOWARN);
+	if (!buf) {
+		kvfree(buf_prevkey);
+		return -ENOMEM;
+	}
+
+	err = -EFAULT;
+	prev_key = NULL;
+	if (ubatch && copy_from_user(buf_prevkey, ubatch, map->key_size))
+		goto free_buf;
+	key = buf;
+	value = key + map->key_size;
+	if (ubatch)
+		prev_key = buf_prevkey;
+
+	for (cp = 0; cp < max_count;) {
+		rcu_read_lock();
+		err = map->ops->map_get_next_key(map, prev_key, key);
+		rcu_read_unlock();
+		if (err)
+			break;
+		err = bpf_map_copy_value(map, key, value,
+					 attr->batch.elem_flags);
+
+		if (err == -ENOENT) {
+			if (retry) {
+				retry--;
+				continue;
+			}
+			err = -EINTR;
+			break;
+		}
+
+		if (err)
+			goto free_buf;
+
+		if (copy_to_user(keys + cp * map->key_size, key,
+				 map->key_size)) {
+			err = -EFAULT;
+			goto free_buf;
+		}
+		if (copy_to_user(values + cp * value_size, value, value_size)) {
+			err = -EFAULT;
+			goto free_buf;
+		}
+
+		if (!prev_key)
+			prev_key = buf_prevkey;
+
+		swap(prev_key, key);
+		retry = MAP_LOOKUP_RETRIES;
+		cp++;
+		cond_resched();
+	}
+
+	if (err == -EFAULT)
+		goto free_buf;
+
+	if ((copy_to_user(&uattr->batch.count, &cp, sizeof(cp)) ||
+		    (cp && copy_to_user(uobatch, prev_key, map->key_size))))
+		err = -EFAULT;
+
+free_buf:
+	kvfree(buf_prevkey);
+	kvfree(buf);
+	return err;
+}
+
+#define BPF_MAP_LOOKUP_AND_DELETE_ELEM_LAST_FIELD flags
+
+static int map_lookup_and_delete_elem(union bpf_attr *attr)
+{
+	void __user *ukey = u64_to_user_ptr(attr->key);
+	void __user *uvalue = u64_to_user_ptr(attr->value);
+	int ufd = attr->map_fd;
+	struct bpf_map *map;
+	void *key, *value;
+	u32 value_size;
+	struct fd f;
+	int err;
+
+	if (CHECK_ATTR(BPF_MAP_LOOKUP_AND_DELETE_ELEM))
+		return -EINVAL;
+
+	if (attr->flags & ~BPF_F_LOCK)
+		return -EINVAL;
+
+	f = fdget(ufd);
+	map = __bpf_map_get(f);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+	bpf_map_write_active_inc(map);
+	if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ) ||
+	    !(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
+		err = -EPERM;
+		goto err_put;
+	}
+
+	if (attr->flags &&
+	    (map->map_type == BPF_MAP_TYPE_QUEUE ||
+	     map->map_type == BPF_MAP_TYPE_STACK)) {
+		err = -EINVAL;
+		goto err_put;
+	}
+
+	if ((attr->flags & BPF_F_LOCK) &&
+	    !map_value_has_spin_lock(map)) {
+		err = -EINVAL;
+		goto err_put;
+	}
+
+	key = __bpf_copy_key(ukey, map->key_size);
+	if (IS_ERR(key)) {
+		err = PTR_ERR(key);
+		goto err_put;
+	}
+
+	value_size = bpf_map_value_size(map);
+
+	err = -ENOMEM;
+	value = kvmalloc(value_size, GFP_USER | __GFP_NOWARN);
+	if (!value)
+		goto free_key;
+
+	err = -ENOTSUPP;
+	if (map->map_type == BPF_MAP_TYPE_QUEUE ||
+	    map->map_type == BPF_MAP_TYPE_STACK) {
+		err = map->ops->map_pop_elem(map, value);
+	} else if (map->map_type == BPF_MAP_TYPE_HASH ||
+		   map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
+		   map->map_type == BPF_MAP_TYPE_LRU_HASH ||
+		   map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
+		if (!bpf_map_is_dev_bound(map)) {
+			bpf_disable_instrumentation();
+			rcu_read_lock();
+			err = map->ops->map_lookup_and_delete_elem(map, key, value, attr->flags);
+			rcu_read_unlock();
+			bpf_enable_instrumentation();
+		}
+	}
+
+	if (err)
+		goto free_value;
+
+	if (copy_to_user(uvalue, value, value_size) != 0) {
+		err = -EFAULT;
+		goto free_value;
+	}
+
+	err = 0;
+
+free_value:
+	kvfree(value);
+free_key:
+	kvfree(key);
+err_put:
+	bpf_map_write_active_dec(map);
+	fdput(f);
+	return err;
+}
+
+#define BPF_MAP_FREEZE_LAST_FIELD map_fd
+
+static int map_freeze(const union bpf_attr *attr)
+{
+	int err = 0, ufd = attr->map_fd;
+	struct bpf_map *map;
+	struct fd f;
+
+	if (CHECK_ATTR(BPF_MAP_FREEZE))
+		return -EINVAL;
+
+	f = fdget(ufd);
+	map = __bpf_map_get(f);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+
+	if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS ||
+	    map_value_has_timer(map) || map_value_has_kptrs(map)) {
+		fdput(f);
+		return -ENOTSUPP;
+	}
+
+	mutex_lock(&map->freeze_mutex);
+	if (bpf_map_write_active(map)) {
+		err = -EBUSY;
+		goto err_put;
+	}
+	if (READ_ONCE(map->frozen)) {
+		err = -EBUSY;
+		goto err_put;
+	}
+	if (!bpf_capable()) {
+		err = -EPERM;
+		goto err_put;
+	}
+
+	WRITE_ONCE(map->frozen, true);
+err_put:
+	mutex_unlock(&map->freeze_mutex);
+	fdput(f);
+	return err;
+}
+
+static const struct bpf_prog_ops * const bpf_prog_types[] = {
+#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
+	[_id] = & _name ## _prog_ops,
+#define BPF_MAP_TYPE(_id, _ops)
+#define BPF_LINK_TYPE(_id, _name)
+#include <linux/bpf_types.h>
+#undef BPF_PROG_TYPE
+#undef BPF_MAP_TYPE
+#undef BPF_LINK_TYPE
+};
+
+static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)
+{
+	const struct bpf_prog_ops *ops;
+
+	if (type >= ARRAY_SIZE(bpf_prog_types))
+		return -EINVAL;
+	type = array_index_nospec(type, ARRAY_SIZE(bpf_prog_types));
+	ops = bpf_prog_types[type];
+	if (!ops)
+		return -EINVAL;
+
+	if (!bpf_prog_is_dev_bound(prog->aux))
+		prog->aux->ops = ops;
+	else
+		prog->aux->ops = &bpf_offload_prog_ops;
+	prog->type = type;
+	return 0;
+}
+
+enum bpf_audit {
+	BPF_AUDIT_LOAD,
+	BPF_AUDIT_UNLOAD,
+	BPF_AUDIT_MAX,
+};
+
+static const char * const bpf_audit_str[BPF_AUDIT_MAX] = {
+	[BPF_AUDIT_LOAD]   = "LOAD",
+	[BPF_AUDIT_UNLOAD] = "UNLOAD",
+};
+
+static void bpf_audit_prog(const struct bpf_prog *prog, unsigned int op)
+{
+	struct audit_context *ctx = NULL;
+	struct audit_buffer *ab;
+
+	if (WARN_ON_ONCE(op >= BPF_AUDIT_MAX))
+		return;
+	if (audit_enabled == AUDIT_OFF)
+		return;
+	if (!in_irq() && !irqs_disabled())
+		ctx = audit_context();
+	ab = audit_log_start(ctx, GFP_ATOMIC, AUDIT_BPF);
+	if (unlikely(!ab))
+		return;
+	audit_log_format(ab, "prog-id=%u op=%s",
+			 prog->aux->id, bpf_audit_str[op]);
+	audit_log_end(ab);
+}
+
+static int bpf_prog_alloc_id(struct bpf_prog *prog)
+{
+	int id;
+
+	idr_preload(GFP_KERNEL);
+	spin_lock_bh(&prog_idr_lock);
+	id = idr_alloc_cyclic(&prog_idr, prog, 1, INT_MAX, GFP_ATOMIC);
+	if (id > 0)
+		prog->aux->id = id;
+	spin_unlock_bh(&prog_idr_lock);
+	idr_preload_end();
+
+	/* id is in [1, INT_MAX) */
+	if (WARN_ON_ONCE(!id))
+		return -ENOSPC;
+
+	return id > 0 ? 0 : id;
+}
+
+void bpf_prog_free_id(struct bpf_prog *prog, bool do_idr_lock)
+{
+	unsigned long flags;
+
+	/* cBPF to eBPF migrations are currently not in the idr store.
+	 * Offloaded programs are removed from the store when their device
+	 * disappears - even if someone grabs an fd to them they are unusable,
+	 * simply waiting for refcnt to drop to be freed.
+	 */
+	if (!prog->aux->id)
+		return;
+
+	if (do_idr_lock)
+		spin_lock_irqsave(&prog_idr_lock, flags);
+	else
+		__acquire(&prog_idr_lock);
+
+	idr_remove(&prog_idr, prog->aux->id);
+	prog->aux->id = 0;
+
+	if (do_idr_lock)
+		spin_unlock_irqrestore(&prog_idr_lock, flags);
+	else
+		__release(&prog_idr_lock);
+}
+
+static void __bpf_prog_put_rcu(struct rcu_head *rcu)
+{
+	struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu);
+
+	kvfree(aux->func_info);
+	kfree(aux->func_info_aux);
+	free_uid(aux->user);
+	security_bpf_prog_free(aux);
+	bpf_prog_free(aux->prog);
+}
+
+static void __bpf_prog_put_noref(struct bpf_prog *prog, bool deferred)
+{
+	bpf_prog_kallsyms_del_all(prog);
+	btf_put(prog->aux->btf);
+	kvfree(prog->aux->jited_linfo);
+	kvfree(prog->aux->linfo);
+	kfree(prog->aux->kfunc_tab);
+	if (prog->aux->attach_btf)
+		btf_put(prog->aux->attach_btf);
+
+	if (deferred) {
+		if (prog->aux->sleepable)
+			call_rcu_tasks_trace(&prog->aux->rcu, __bpf_prog_put_rcu);
+		else
+			call_rcu(&prog->aux->rcu, __bpf_prog_put_rcu);
+	} else {
+		__bpf_prog_put_rcu(&prog->aux->rcu);
+	}
+}
+
+static void bpf_prog_put_deferred(struct work_struct *work)
+{
+	struct bpf_prog_aux *aux;
+	struct bpf_prog *prog;
+
+	aux = container_of(work, struct bpf_prog_aux, work);
+	prog = aux->prog;
+	perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_UNLOAD, 0);
+	bpf_audit_prog(prog, BPF_AUDIT_UNLOAD);
+	bpf_prog_free_id(prog, true);
+	__bpf_prog_put_noref(prog, true);
+}
+
+static void __bpf_prog_put(struct bpf_prog *prog, bool do_idr_lock)
+{
+	struct bpf_prog_aux *aux = prog->aux;
+
+	if (atomic64_dec_and_test(&aux->refcnt)) {
+		if (in_irq() || irqs_disabled()) {
+			INIT_WORK(&aux->work, bpf_prog_put_deferred);
+			schedule_work(&aux->work);
+		} else {
+			bpf_prog_put_deferred(&aux->work);
+		}
+	}
+}
+
+void bpf_prog_put(struct bpf_prog *prog)
+{
+	__bpf_prog_put(prog, true);
+}
+EXPORT_SYMBOL_GPL(bpf_prog_put);
+
+static int bpf_prog_release(struct inode *inode, struct file *filp)
+{
+	struct bpf_prog *prog = filp->private_data;
+
+	bpf_prog_put(prog);
+	return 0;
+}
+
+struct bpf_prog_kstats {
+	u64 nsecs;
+	u64 cnt;
+	u64 misses;
+};
+
+void notrace bpf_prog_inc_misses_counter(struct bpf_prog *prog)
+{
+	struct bpf_prog_stats *stats;
+	unsigned int flags;
+
+	stats = this_cpu_ptr(prog->stats);
+	flags = u64_stats_update_begin_irqsave(&stats->syncp);
+	u64_stats_inc(&stats->misses);
+	u64_stats_update_end_irqrestore(&stats->syncp, flags);
+}
+
+static void bpf_prog_get_stats(const struct bpf_prog *prog,
+			       struct bpf_prog_kstats *stats)
+{
+	u64 nsecs = 0, cnt = 0, misses = 0;
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		const struct bpf_prog_stats *st;
+		unsigned int start;
+		u64 tnsecs, tcnt, tmisses;
+
+		st = per_cpu_ptr(prog->stats, cpu);
+		do {
+			start = u64_stats_fetch_begin_irq(&st->syncp);
+			tnsecs = u64_stats_read(&st->nsecs);
+			tcnt = u64_stats_read(&st->cnt);
+			tmisses = u64_stats_read(&st->misses);
+		} while (u64_stats_fetch_retry_irq(&st->syncp, start));
+		nsecs += tnsecs;
+		cnt += tcnt;
+		misses += tmisses;
+	}
+	stats->nsecs = nsecs;
+	stats->cnt = cnt;
+	stats->misses = misses;
+}
+
+#ifdef CONFIG_PROC_FS
+static void bpf_prog_show_fdinfo(struct seq_file *m, struct file *filp)
+{
+	const struct bpf_prog *prog = filp->private_data;
+	char prog_tag[sizeof(prog->tag) * 2 + 1] = { };
+	struct bpf_prog_kstats stats;
+
+	bpf_prog_get_stats(prog, &stats);
+	bin2hex(prog_tag, prog->tag, sizeof(prog->tag));
+	seq_printf(m,
+		   "prog_type:\t%u\n"
+		   "prog_jited:\t%u\n"
+		   "prog_tag:\t%s\n"
+		   "memlock:\t%llu\n"
+		   "prog_id:\t%u\n"
+		   "run_time_ns:\t%llu\n"
+		   "run_cnt:\t%llu\n"
+		   "recursion_misses:\t%llu\n"
+		   "verified_insns:\t%u\n",
+		   prog->type,
+		   prog->jited,
+		   prog_tag,
+		   prog->pages * 1ULL << PAGE_SHIFT,
+		   prog->aux->id,
+		   stats.nsecs,
+		   stats.cnt,
+		   stats.misses,
+		   prog->aux->verified_insns);
+}
+#endif
+
+const struct file_operations bpf_prog_fops = {
+#ifdef CONFIG_PROC_FS
+	.show_fdinfo	= bpf_prog_show_fdinfo,
+#endif
+	.release	= bpf_prog_release,
+	.read		= bpf_dummy_read,
+	.write		= bpf_dummy_write,
+};
+
+int bpf_prog_new_fd(struct bpf_prog *prog)
+{
+	int ret;
+
+	ret = security_bpf_prog(prog);
+	if (ret < 0)
+		return ret;
+
+	return anon_inode_getfd("bpf-prog", &bpf_prog_fops, prog,
+				O_RDWR | O_CLOEXEC);
+}
+
+static struct bpf_prog *____bpf_prog_get(struct fd f)
+{
+	if (!f.file)
+		return ERR_PTR(-EBADF);
+	if (f.file->f_op != &bpf_prog_fops) {
+		fdput(f);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return f.file->private_data;
+}
+
+void bpf_prog_add(struct bpf_prog *prog, int i)
+{
+	atomic64_add(i, &prog->aux->refcnt);
+}
+EXPORT_SYMBOL_GPL(bpf_prog_add);
+
+void bpf_prog_sub(struct bpf_prog *prog, int i)
+{
+	/* Only to be used for undoing previous bpf_prog_add() in some
+	 * error path. We still know that another entity in our call
+	 * path holds a reference to the program, thus atomic_sub() can
+	 * be safely used in such cases!
+	 */
+	WARN_ON(atomic64_sub_return(i, &prog->aux->refcnt) == 0);
+}
+EXPORT_SYMBOL_GPL(bpf_prog_sub);
+
+void bpf_prog_inc(struct bpf_prog *prog)
+{
+	atomic64_inc(&prog->aux->refcnt);
+}
+EXPORT_SYMBOL_GPL(bpf_prog_inc);
+
+/* prog_idr_lock should have been held */
+struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog)
+{
+	int refold;
+
+	refold = atomic64_fetch_add_unless(&prog->aux->refcnt, 1, 0);
+
+	if (!refold)
+		return ERR_PTR(-ENOENT);
+
+	return prog;
+}
+EXPORT_SYMBOL_GPL(bpf_prog_inc_not_zero);
+
+bool bpf_prog_get_ok(struct bpf_prog *prog,
+			    enum bpf_prog_type *attach_type, bool attach_drv)
+{
+	/* not an attachment, just a refcount inc, always allow */
+	if (!attach_type)
+		return true;
+
+	if (prog->type != *attach_type)
+		return false;
+	if (bpf_prog_is_dev_bound(prog->aux) && !attach_drv)
+		return false;
+
+	return true;
+}
+
+static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *attach_type,
+				       bool attach_drv)
+{
+	struct fd f = fdget(ufd);
+	struct bpf_prog *prog;
+
+	prog = ____bpf_prog_get(f);
+	if (IS_ERR(prog))
+		return prog;
+	if (!bpf_prog_get_ok(prog, attach_type, attach_drv)) {
+		prog = ERR_PTR(-EINVAL);
+		goto out;
+	}
+
+	bpf_prog_inc(prog);
+out:
+	fdput(f);
+	return prog;
+}
+
+struct bpf_prog *bpf_prog_get(u32 ufd)
+{
+	return __bpf_prog_get(ufd, NULL, false);
+}
+
+struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type,
+				       bool attach_drv)
+{
+	return __bpf_prog_get(ufd, &type, attach_drv);
+}
+EXPORT_SYMBOL_GPL(bpf_prog_get_type_dev);
+
+/* Initially all BPF programs could be loaded w/o specifying
+ * expected_attach_type. Later for some of them specifying expected_attach_type
+ * at load time became required so that program could be validated properly.
+ * Programs of types that are allowed to be loaded both w/ and w/o (for
+ * backward compatibility) expected_attach_type, should have the default attach
+ * type assigned to expected_attach_type for the latter case, so that it can be
+ * validated later at attach time.
+ *
+ * bpf_prog_load_fixup_attach_type() sets expected_attach_type in @attr if
+ * prog type requires it but has some attach types that have to be backward
+ * compatible.
+ */
+static void bpf_prog_load_fixup_attach_type(union bpf_attr *attr)
+{
+	switch (attr->prog_type) {
+	case BPF_PROG_TYPE_CGROUP_SOCK:
+		/* Unfortunately BPF_ATTACH_TYPE_UNSPEC enumeration doesn't
+		 * exist so checking for non-zero is the way to go here.
+		 */
+		if (!attr->expected_attach_type)
+			attr->expected_attach_type =
+				BPF_CGROUP_INET_SOCK_CREATE;
+		break;
+	case BPF_PROG_TYPE_SK_REUSEPORT:
+		if (!attr->expected_attach_type)
+			attr->expected_attach_type =
+				BPF_SK_REUSEPORT_SELECT;
+		break;
+	}
+}
+
+static int
+bpf_prog_load_check_attach(enum bpf_prog_type prog_type,
+			   enum bpf_attach_type expected_attach_type,
+			   struct btf *attach_btf, u32 btf_id,
+			   struct bpf_prog *dst_prog)
+{
+	if (btf_id) {
+		if (btf_id > BTF_MAX_TYPE)
+			return -EINVAL;
+
+		if (!attach_btf && !dst_prog)
+			return -EINVAL;
+
+		switch (prog_type) {
+		case BPF_PROG_TYPE_TRACING:
+		case BPF_PROG_TYPE_LSM:
+		case BPF_PROG_TYPE_STRUCT_OPS:
+		case BPF_PROG_TYPE_EXT:
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	if (attach_btf && (!btf_id || dst_prog))
+		return -EINVAL;
+
+	if (dst_prog && prog_type != BPF_PROG_TYPE_TRACING &&
+	    prog_type != BPF_PROG_TYPE_EXT)
+		return -EINVAL;
+
+	switch (prog_type) {
+	case BPF_PROG_TYPE_CGROUP_SOCK:
+		switch (expected_attach_type) {
+		case BPF_CGROUP_INET_SOCK_CREATE:
+		case BPF_CGROUP_INET_SOCK_RELEASE:
+		case BPF_CGROUP_INET4_POST_BIND:
+		case BPF_CGROUP_INET6_POST_BIND:
+			return 0;
+		default:
+			return -EINVAL;
+		}
+	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+		switch (expected_attach_type) {
+		case BPF_CGROUP_INET4_BIND:
+		case BPF_CGROUP_INET6_BIND:
+		case BPF_CGROUP_INET4_CONNECT:
+		case BPF_CGROUP_INET6_CONNECT:
+		case BPF_CGROUP_INET4_GETPEERNAME:
+		case BPF_CGROUP_INET6_GETPEERNAME:
+		case BPF_CGROUP_INET4_GETSOCKNAME:
+		case BPF_CGROUP_INET6_GETSOCKNAME:
+		case BPF_CGROUP_UDP4_SENDMSG:
+		case BPF_CGROUP_UDP6_SENDMSG:
+		case BPF_CGROUP_UDP4_RECVMSG:
+		case BPF_CGROUP_UDP6_RECVMSG:
+			return 0;
+		default:
+			return -EINVAL;
+		}
+	case BPF_PROG_TYPE_CGROUP_SKB:
+		switch (expected_attach_type) {
+		case BPF_CGROUP_INET_INGRESS:
+		case BPF_CGROUP_INET_EGRESS:
+			return 0;
+		default:
+			return -EINVAL;
+		}
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+		switch (expected_attach_type) {
+		case BPF_CGROUP_SETSOCKOPT:
+		case BPF_CGROUP_GETSOCKOPT:
+			return 0;
+		default:
+			return -EINVAL;
+		}
+	case BPF_PROG_TYPE_SK_LOOKUP:
+		if (expected_attach_type == BPF_SK_LOOKUP)
+			return 0;
+		return -EINVAL;
+	case BPF_PROG_TYPE_SK_REUSEPORT:
+		switch (expected_attach_type) {
+		case BPF_SK_REUSEPORT_SELECT:
+		case BPF_SK_REUSEPORT_SELECT_OR_MIGRATE:
+			return 0;
+		default:
+			return -EINVAL;
+		}
+	case BPF_PROG_TYPE_SYSCALL:
+	case BPF_PROG_TYPE_EXT:
+		if (expected_attach_type)
+			return -EINVAL;
+		fallthrough;
+	default:
+		return 0;
+	}
+}
+
+static bool is_net_admin_prog_type(enum bpf_prog_type prog_type)
+{
+	switch (prog_type) {
+	case BPF_PROG_TYPE_SCHED_CLS:
+	case BPF_PROG_TYPE_SCHED_ACT:
+	case BPF_PROG_TYPE_XDP:
+	case BPF_PROG_TYPE_LWT_IN:
+	case BPF_PROG_TYPE_LWT_OUT:
+	case BPF_PROG_TYPE_LWT_XMIT:
+	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
+	case BPF_PROG_TYPE_SK_SKB:
+	case BPF_PROG_TYPE_SK_MSG:
+	case BPF_PROG_TYPE_LIRC_MODE2:
+	case BPF_PROG_TYPE_FLOW_DISSECTOR:
+	case BPF_PROG_TYPE_CGROUP_DEVICE:
+	case BPF_PROG_TYPE_CGROUP_SOCK:
+	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+	case BPF_PROG_TYPE_CGROUP_SYSCTL:
+	case BPF_PROG_TYPE_SOCK_OPS:
+	case BPF_PROG_TYPE_EXT: /* extends any prog */
+		return true;
+	case BPF_PROG_TYPE_CGROUP_SKB:
+		/* always unpriv */
+	case BPF_PROG_TYPE_SK_REUSEPORT:
+		/* equivalent to SOCKET_FILTER. need CAP_BPF only */
+	default:
+		return false;
+	}
+}
+
+static bool is_perfmon_prog_type(enum bpf_prog_type prog_type)
+{
+	switch (prog_type) {
+	case BPF_PROG_TYPE_KPROBE:
+	case BPF_PROG_TYPE_TRACEPOINT:
+	case BPF_PROG_TYPE_PERF_EVENT:
+	case BPF_PROG_TYPE_RAW_TRACEPOINT:
+	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
+	case BPF_PROG_TYPE_TRACING:
+	case BPF_PROG_TYPE_LSM:
+	case BPF_PROG_TYPE_STRUCT_OPS: /* has access to struct sock */
+	case BPF_PROG_TYPE_EXT: /* extends any prog */
+		return true;
+	default:
+		return false;
+	}
+}
+
+/* last field in 'union bpf_attr' used by this command */
+#define	BPF_PROG_LOAD_LAST_FIELD core_relo_rec_size
+
+static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr)
+{
+	enum bpf_prog_type type = attr->prog_type;
+	struct bpf_prog *prog, *dst_prog = NULL;
+	struct btf *attach_btf = NULL;
+	int err;
+	char license[128];
+	bool is_gpl;
+
+	if (CHECK_ATTR(BPF_PROG_LOAD))
+		return -EINVAL;
+
+	if (attr->prog_flags & ~(BPF_F_STRICT_ALIGNMENT |
+				 BPF_F_ANY_ALIGNMENT |
+				 BPF_F_TEST_STATE_FREQ |
+				 BPF_F_SLEEPABLE |
+				 BPF_F_TEST_RND_HI32 |
+				 BPF_F_XDP_HAS_FRAGS))
+		return -EINVAL;
+
+	if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) &&
+	    (attr->prog_flags & BPF_F_ANY_ALIGNMENT) &&
+	    !bpf_capable())
+		return -EPERM;
+
+	/* copy eBPF program license from user space */
+	if (strncpy_from_bpfptr(license,
+				make_bpfptr(attr->license, uattr.is_kernel),
+				sizeof(license) - 1) < 0)
+		return -EFAULT;
+	license[sizeof(license) - 1] = 0;
+
+	/* eBPF programs must be GPL compatible to use GPL-ed functions */
+	is_gpl = license_is_gpl_compatible(license);
+
+	if (attr->insn_cnt == 0 ||
+	    attr->insn_cnt > (bpf_capable() ? BPF_COMPLEXITY_LIMIT_INSNS : BPF_MAXINSNS))
+		return -E2BIG;
+	if (type != BPF_PROG_TYPE_SOCKET_FILTER &&
+	    type != BPF_PROG_TYPE_CGROUP_SKB &&
+	    !bpf_capable())
+		return -EPERM;
+
+	if (is_net_admin_prog_type(type) && !capable(CAP_NET_ADMIN) && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	if (is_perfmon_prog_type(type) && !perfmon_capable())
+		return -EPERM;
+
+	/* attach_prog_fd/attach_btf_obj_fd can specify fd of either bpf_prog
+	 * or btf, we need to check which one it is
+	 */
+	if (attr->attach_prog_fd) {
+		dst_prog = bpf_prog_get(attr->attach_prog_fd);
+		if (IS_ERR(dst_prog)) {
+			dst_prog = NULL;
+			attach_btf = btf_get_by_fd(attr->attach_btf_obj_fd);
+			if (IS_ERR(attach_btf))
+				return -EINVAL;
+			if (!btf_is_kernel(attach_btf)) {
+				/* attaching through specifying bpf_prog's BTF
+				 * objects directly might be supported eventually
+				 */
+				btf_put(attach_btf);
+				return -ENOTSUPP;
+			}
+		}
+	} else if (attr->attach_btf_id) {
+		/* fall back to vmlinux BTF, if BTF type ID is specified */
+		attach_btf = bpf_get_btf_vmlinux();
+		if (IS_ERR(attach_btf))
+			return PTR_ERR(attach_btf);
+		if (!attach_btf)
+			return -EINVAL;
+		btf_get(attach_btf);
+	}
+
+	bpf_prog_load_fixup_attach_type(attr);
+	if (bpf_prog_load_check_attach(type, attr->expected_attach_type,
+				       attach_btf, attr->attach_btf_id,
+				       dst_prog)) {
+		if (dst_prog)
+			bpf_prog_put(dst_prog);
+		if (attach_btf)
+			btf_put(attach_btf);
+		return -EINVAL;
+	}
+
+	/* plain bpf_prog allocation */
+	prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER);
+	if (!prog) {
+		if (dst_prog)
+			bpf_prog_put(dst_prog);
+		if (attach_btf)
+			btf_put(attach_btf);
+		return -ENOMEM;
+	}
+
+	prog->expected_attach_type = attr->expected_attach_type;
+	prog->aux->attach_btf = attach_btf;
+	prog->aux->attach_btf_id = attr->attach_btf_id;
+	prog->aux->dst_prog = dst_prog;
+	prog->aux->offload_requested = !!attr->prog_ifindex;
+	prog->aux->sleepable = attr->prog_flags & BPF_F_SLEEPABLE;
+	prog->aux->xdp_has_frags = attr->prog_flags & BPF_F_XDP_HAS_FRAGS;
+
+	err = security_bpf_prog_alloc(prog->aux);
+	if (err)
+		goto free_prog;
+
+	prog->aux->user = get_current_user();
+	prog->len = attr->insn_cnt;
+
+	err = -EFAULT;
+	if (copy_from_bpfptr(prog->insns,
+			     make_bpfptr(attr->insns, uattr.is_kernel),
+			     bpf_prog_insn_size(prog)) != 0)
+		goto free_prog_sec;
+
+	prog->orig_prog = NULL;
+	prog->jited = 0;
+
+	atomic64_set(&prog->aux->refcnt, 1);
+	prog->gpl_compatible = is_gpl ? 1 : 0;
+
+	if (bpf_prog_is_dev_bound(prog->aux)) {
+		err = bpf_prog_offload_init(prog, attr);
+		if (err)
+			goto free_prog_sec;
+	}
+
+	/* find program type: socket_filter vs tracing_filter */
+	err = find_prog_type(type, prog);
+	if (err < 0)
+		goto free_prog_sec;
+
+	prog->aux->load_time = ktime_get_boottime_ns();
+	err = bpf_obj_name_cpy(prog->aux->name, attr->prog_name,
+			       sizeof(attr->prog_name));
+	if (err < 0)
+		goto free_prog_sec;
+
+	/* run eBPF verifier */
+	err = bpf_check(&prog, attr, uattr);
+	if (err < 0)
+		goto free_used_maps;
+
+	prog = bpf_prog_select_runtime(prog, &err);
+	if (err < 0)
+		goto free_used_maps;
+
+	err = bpf_prog_alloc_id(prog);
+	if (err)
+		goto free_used_maps;
+
+	/* Upon success of bpf_prog_alloc_id(), the BPF prog is
+	 * effectively publicly exposed. However, retrieving via
+	 * bpf_prog_get_fd_by_id() will take another reference,
+	 * therefore it cannot be gone underneath us.
+	 *
+	 * Only for the time /after/ successful bpf_prog_new_fd()
+	 * and before returning to userspace, we might just hold
+	 * one reference and any parallel close on that fd could
+	 * rip everything out. Hence, below notifications must
+	 * happen before bpf_prog_new_fd().
+	 *
+	 * Also, any failure handling from this point onwards must
+	 * be using bpf_prog_put() given the program is exposed.
+	 */
+	bpf_prog_kallsyms_add(prog);
+	perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_LOAD, 0);
+	bpf_audit_prog(prog, BPF_AUDIT_LOAD);
+
+	err = bpf_prog_new_fd(prog);
+	if (err < 0)
+		bpf_prog_put(prog);
+	return err;
+
+free_used_maps:
+	/* In case we have subprogs, we need to wait for a grace
+	 * period before we can tear down JIT memory since symbols
+	 * are already exposed under kallsyms.
+	 */
+	__bpf_prog_put_noref(prog, prog->aux->func_cnt);
+	return err;
+free_prog_sec:
+	free_uid(prog->aux->user);
+	security_bpf_prog_free(prog->aux);
+free_prog:
+	if (prog->aux->attach_btf)
+		btf_put(prog->aux->attach_btf);
+	bpf_prog_free(prog);
+	return err;
+}
+
+#define BPF_OBJ_LAST_FIELD file_flags
+
+static int bpf_obj_pin(const union bpf_attr *attr)
+{
+	if (CHECK_ATTR(BPF_OBJ) || attr->file_flags != 0)
+		return -EINVAL;
+
+	return bpf_obj_pin_user(attr->bpf_fd, u64_to_user_ptr(attr->pathname));
+}
+
+static int bpf_obj_get(const union bpf_attr *attr)
+{
+	if (CHECK_ATTR(BPF_OBJ) || attr->bpf_fd != 0 ||
+	    attr->file_flags & ~BPF_OBJ_FLAG_MASK)
+		return -EINVAL;
+
+	return bpf_obj_get_user(u64_to_user_ptr(attr->pathname),
+				attr->file_flags);
+}
+
+void bpf_link_init(struct bpf_link *link, enum bpf_link_type type,
+		   const struct bpf_link_ops *ops, struct bpf_prog *prog)
+{
+	atomic64_set(&link->refcnt, 1);
+	link->type = type;
+	link->id = 0;
+	link->ops = ops;
+	link->prog = prog;
+}
+
+static void bpf_link_free_id(int id)
+{
+	if (!id)
+		return;
+
+	spin_lock_bh(&link_idr_lock);
+	idr_remove(&link_idr, id);
+	spin_unlock_bh(&link_idr_lock);
+}
+
+/* Clean up bpf_link and corresponding anon_inode file and FD. After
+ * anon_inode is created, bpf_link can't be just kfree()'d due to deferred
+ * anon_inode's release() call. This helper marksbpf_link as
+ * defunct, releases anon_inode file and puts reserved FD. bpf_prog's refcnt
+ * is not decremented, it's the responsibility of a calling code that failed
+ * to complete bpf_link initialization.
+ */
+void bpf_link_cleanup(struct bpf_link_primer *primer)
+{
+	primer->link->prog = NULL;
+	bpf_link_free_id(primer->id);
+	fput(primer->file);
+	put_unused_fd(primer->fd);
+}
+
+void bpf_link_inc(struct bpf_link *link)
+{
+	atomic64_inc(&link->refcnt);
+}
+
+/* bpf_link_free is guaranteed to be called from process context */
+static void bpf_link_free(struct bpf_link *link)
+{
+	bpf_link_free_id(link->id);
+	if (link->prog) {
+		/* detach BPF program, clean up used resources */
+		link->ops->release(link);
+		bpf_prog_put(link->prog);
+	}
+	/* free bpf_link and its containing memory */
+	link->ops->dealloc(link);
+}
+
+static void bpf_link_put_deferred(struct work_struct *work)
+{
+	struct bpf_link *link = container_of(work, struct bpf_link, work);
+
+	bpf_link_free(link);
+}
+
+/* bpf_link_put can be called from atomic context, but ensures that resources
+ * are freed from process context
+ */
+void bpf_link_put(struct bpf_link *link)
+{
+	if (!atomic64_dec_and_test(&link->refcnt))
+		return;
+
+	if (in_atomic()) {
+		INIT_WORK(&link->work, bpf_link_put_deferred);
+		schedule_work(&link->work);
+	} else {
+		bpf_link_free(link);
+	}
+}
+EXPORT_SYMBOL(bpf_link_put);
+
+static int bpf_link_release(struct inode *inode, struct file *filp)
+{
+	struct bpf_link *link = filp->private_data;
+
+	bpf_link_put(link);
+	return 0;
+}
+
+#ifdef CONFIG_PROC_FS
+#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
+#define BPF_MAP_TYPE(_id, _ops)
+#define BPF_LINK_TYPE(_id, _name) [_id] = #_name,
+static const char *bpf_link_type_strs[] = {
+	[BPF_LINK_TYPE_UNSPEC] = "<invalid>",
+#include <linux/bpf_types.h>
+};
+#undef BPF_PROG_TYPE
+#undef BPF_MAP_TYPE
+#undef BPF_LINK_TYPE
+
+static void bpf_link_show_fdinfo(struct seq_file *m, struct file *filp)
+{
+	const struct bpf_link *link = filp->private_data;
+	const struct bpf_prog *prog = link->prog;
+	char prog_tag[sizeof(prog->tag) * 2 + 1] = { };
+
+	bin2hex(prog_tag, prog->tag, sizeof(prog->tag));
+	seq_printf(m,
+		   "link_type:\t%s\n"
+		   "link_id:\t%u\n"
+		   "prog_tag:\t%s\n"
+		   "prog_id:\t%u\n",
+		   bpf_link_type_strs[link->type],
+		   link->id,
+		   prog_tag,
+		   prog->aux->id);
+	if (link->ops->show_fdinfo)
+		link->ops->show_fdinfo(link, m);
+}
+#endif
+
+static const struct file_operations bpf_link_fops = {
+#ifdef CONFIG_PROC_FS
+	.show_fdinfo	= bpf_link_show_fdinfo,
+#endif
+	.release	= bpf_link_release,
+	.read		= bpf_dummy_read,
+	.write		= bpf_dummy_write,
+};
+
+static int bpf_link_alloc_id(struct bpf_link *link)
+{
+	int id;
+
+	idr_preload(GFP_KERNEL);
+	spin_lock_bh(&link_idr_lock);
+	id = idr_alloc_cyclic(&link_idr, link, 1, INT_MAX, GFP_ATOMIC);
+	spin_unlock_bh(&link_idr_lock);
+	idr_preload_end();
+
+	return id;
+}
+
+/* Prepare bpf_link to be exposed to user-space by allocating anon_inode file,
+ * reserving unused FD and allocating ID from link_idr. This is to be paired
+ * with bpf_link_settle() to install FD and ID and expose bpf_link to
+ * user-space, if bpf_link is successfully attached. If not, bpf_link and
+ * pre-allocated resources are to be freed with bpf_cleanup() call. All the
+ * transient state is passed around in struct bpf_link_primer.
+ * This is preferred way to create and initialize bpf_link, especially when
+ * there are complicated and expensive operations in between creating bpf_link
+ * itself and attaching it to BPF hook. By using bpf_link_prime() and
+ * bpf_link_settle() kernel code using bpf_link doesn't have to perform
+ * expensive (and potentially failing) roll back operations in a rare case
+ * that file, FD, or ID can't be allocated.
+ */
+int bpf_link_prime(struct bpf_link *link, struct bpf_link_primer *primer)
+{
+	struct file *file;
+	int fd, id;
+
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fd < 0)
+		return fd;
+
+
+	id = bpf_link_alloc_id(link);
+	if (id < 0) {
+		put_unused_fd(fd);
+		return id;
+	}
+
+	file = anon_inode_getfile("bpf_link", &bpf_link_fops, link, O_CLOEXEC);
+	if (IS_ERR(file)) {
+		bpf_link_free_id(id);
+		put_unused_fd(fd);
+		return PTR_ERR(file);
+	}
+
+	primer->link = link;
+	primer->file = file;
+	primer->fd = fd;
+	primer->id = id;
+	return 0;
+}
+
+int bpf_link_settle(struct bpf_link_primer *primer)
+{
+	/* make bpf_link fetchable by ID */
+	spin_lock_bh(&link_idr_lock);
+	primer->link->id = primer->id;
+	spin_unlock_bh(&link_idr_lock);
+	/* make bpf_link fetchable by FD */
+	fd_install(primer->fd, primer->file);
+	/* pass through installed FD */
+	return primer->fd;
+}
+
+int bpf_link_new_fd(struct bpf_link *link)
+{
+	return anon_inode_getfd("bpf-link", &bpf_link_fops, link, O_CLOEXEC);
+}
+
+struct bpf_link *bpf_link_get_from_fd(u32 ufd)
+{
+	struct fd f = fdget(ufd);
+	struct bpf_link *link;
+
+	if (!f.file)
+		return ERR_PTR(-EBADF);
+	if (f.file->f_op != &bpf_link_fops) {
+		fdput(f);
+		return ERR_PTR(-EINVAL);
+	}
+
+	link = f.file->private_data;
+	bpf_link_inc(link);
+	fdput(f);
+
+	return link;
+}
+EXPORT_SYMBOL(bpf_link_get_from_fd);
+
+static void bpf_tracing_link_release(struct bpf_link *link)
+{
+	struct bpf_tracing_link *tr_link =
+		container_of(link, struct bpf_tracing_link, link.link);
+
+	WARN_ON_ONCE(bpf_trampoline_unlink_prog(&tr_link->link,
+						tr_link->trampoline));
+
+	bpf_trampoline_put(tr_link->trampoline);
+
+	/* tgt_prog is NULL if target is a kernel function */
+	if (tr_link->tgt_prog)
+		bpf_prog_put(tr_link->tgt_prog);
+}
+
+static void bpf_tracing_link_dealloc(struct bpf_link *link)
+{
+	struct bpf_tracing_link *tr_link =
+		container_of(link, struct bpf_tracing_link, link.link);
+
+	kfree(tr_link);
+}
+
+static void bpf_tracing_link_show_fdinfo(const struct bpf_link *link,
+					 struct seq_file *seq)
+{
+	struct bpf_tracing_link *tr_link =
+		container_of(link, struct bpf_tracing_link, link.link);
+
+	seq_printf(seq,
+		   "attach_type:\t%d\n",
+		   tr_link->attach_type);
+}
+
+static int bpf_tracing_link_fill_link_info(const struct bpf_link *link,
+					   struct bpf_link_info *info)
+{
+	struct bpf_tracing_link *tr_link =
+		container_of(link, struct bpf_tracing_link, link.link);
+
+	info->tracing.attach_type = tr_link->attach_type;
+	bpf_trampoline_unpack_key(tr_link->trampoline->key,
+				  &info->tracing.target_obj_id,
+				  &info->tracing.target_btf_id);
+
+	return 0;
+}
+
+static const struct bpf_link_ops bpf_tracing_link_lops = {
+	.release = bpf_tracing_link_release,
+	.dealloc = bpf_tracing_link_dealloc,
+	.show_fdinfo = bpf_tracing_link_show_fdinfo,
+	.fill_link_info = bpf_tracing_link_fill_link_info,
+};
+
+static int bpf_tracing_prog_attach(struct bpf_prog *prog,
+				   int tgt_prog_fd,
+				   u32 btf_id,
+				   u64 bpf_cookie)
+{
+	struct bpf_link_primer link_primer;
+	struct bpf_prog *tgt_prog = NULL;
+	struct bpf_trampoline *tr = NULL;
+	struct bpf_tracing_link *link;
+	u64 key = 0;
+	int err;
+
+	switch (prog->type) {
+	case BPF_PROG_TYPE_TRACING:
+		if (prog->expected_attach_type != BPF_TRACE_FENTRY &&
+		    prog->expected_attach_type != BPF_TRACE_FEXIT &&
+		    prog->expected_attach_type != BPF_MODIFY_RETURN) {
+			err = -EINVAL;
+			goto out_put_prog;
+		}
+		break;
+	case BPF_PROG_TYPE_EXT:
+		if (prog->expected_attach_type != 0) {
+			err = -EINVAL;
+			goto out_put_prog;
+		}
+		break;
+	case BPF_PROG_TYPE_LSM:
+		if (prog->expected_attach_type != BPF_LSM_MAC) {
+			err = -EINVAL;
+			goto out_put_prog;
+		}
+		break;
+	default:
+		err = -EINVAL;
+		goto out_put_prog;
+	}
+
+	if (!!tgt_prog_fd != !!btf_id) {
+		err = -EINVAL;
+		goto out_put_prog;
+	}
+
+	if (tgt_prog_fd) {
+		/* For now we only allow new targets for BPF_PROG_TYPE_EXT */
+		if (prog->type != BPF_PROG_TYPE_EXT) {
+			err = -EINVAL;
+			goto out_put_prog;
+		}
+
+		tgt_prog = bpf_prog_get(tgt_prog_fd);
+		if (IS_ERR(tgt_prog)) {
+			err = PTR_ERR(tgt_prog);
+			tgt_prog = NULL;
+			goto out_put_prog;
+		}
+
+		key = bpf_trampoline_compute_key(tgt_prog, NULL, btf_id);
+	}
+
+	link = kzalloc(sizeof(*link), GFP_USER);
+	if (!link) {
+		err = -ENOMEM;
+		goto out_put_prog;
+	}
+	bpf_link_init(&link->link.link, BPF_LINK_TYPE_TRACING,
+		      &bpf_tracing_link_lops, prog);
+	link->attach_type = prog->expected_attach_type;
+	link->link.cookie = bpf_cookie;
+
+	mutex_lock(&prog->aux->dst_mutex);
+
+	/* There are a few possible cases here:
+	 *
+	 * - if prog->aux->dst_trampoline is set, the program was just loaded
+	 *   and not yet attached to anything, so we can use the values stored
+	 *   in prog->aux
+	 *
+	 * - if prog->aux->dst_trampoline is NULL, the program has already been
+         *   attached to a target and its initial target was cleared (below)
+	 *
+	 * - if tgt_prog != NULL, the caller specified tgt_prog_fd +
+	 *   target_btf_id using the link_create API.
+	 *
+	 * - if tgt_prog == NULL when this function was called using the old
+	 *   raw_tracepoint_open API, and we need a target from prog->aux
+	 *
+	 * - if prog->aux->dst_trampoline and tgt_prog is NULL, the program
+	 *   was detached and is going for re-attachment.
+	 *
+	 * - if prog->aux->dst_trampoline is NULL and tgt_prog and prog->aux->attach_btf
+	 *   are NULL, then program was already attached and user did not provide
+	 *   tgt_prog_fd so we have no way to find out or create trampoline
+	 */
+	if (!prog->aux->dst_trampoline && !tgt_prog) {
+		/*
+		 * Allow re-attach for TRACING and LSM programs. If it's
+		 * currently linked, bpf_trampoline_link_prog will fail.
+		 * EXT programs need to specify tgt_prog_fd, so they
+		 * re-attach in separate code path.
+		 */
+		if (prog->type != BPF_PROG_TYPE_TRACING &&
+		    prog->type != BPF_PROG_TYPE_LSM) {
+			err = -EINVAL;
+			goto out_unlock;
+		}
+		/* We can allow re-attach only if we have valid attach_btf. */
+		if (!prog->aux->attach_btf) {
+			err = -EINVAL;
+			goto out_unlock;
+		}
+		btf_id = prog->aux->attach_btf_id;
+		key = bpf_trampoline_compute_key(NULL, prog->aux->attach_btf, btf_id);
+	}
+
+	if (!prog->aux->dst_trampoline ||
+	    (key && key != prog->aux->dst_trampoline->key)) {
+		/* If there is no saved target, or the specified target is
+		 * different from the destination specified at load time, we
+		 * need a new trampoline and a check for compatibility
+		 */
+		struct bpf_attach_target_info tgt_info = {};
+
+		err = bpf_check_attach_target(NULL, prog, tgt_prog, btf_id,
+					      &tgt_info);
+		if (err)
+			goto out_unlock;
+
+		tr = bpf_trampoline_get(key, &tgt_info);
+		if (!tr) {
+			err = -ENOMEM;
+			goto out_unlock;
+		}
+	} else {
+		/* The caller didn't specify a target, or the target was the
+		 * same as the destination supplied during program load. This
+		 * means we can reuse the trampoline and reference from program
+		 * load time, and there is no need to allocate a new one. This
+		 * can only happen once for any program, as the saved values in
+		 * prog->aux are cleared below.
+		 */
+		tr = prog->aux->dst_trampoline;
+		tgt_prog = prog->aux->dst_prog;
+	}
+
+	err = bpf_link_prime(&link->link.link, &link_primer);
+	if (err)
+		goto out_unlock;
+
+	err = bpf_trampoline_link_prog(&link->link, tr);
+	if (err) {
+		bpf_link_cleanup(&link_primer);
+		link = NULL;
+		goto out_unlock;
+	}
+
+	link->tgt_prog = tgt_prog;
+	link->trampoline = tr;
+
+	/* Always clear the trampoline and target prog from prog->aux to make
+	 * sure the original attach destination is not kept alive after a
+	 * program is (re-)attached to another target.
+	 */
+	if (prog->aux->dst_prog &&
+	    (tgt_prog_fd || tr != prog->aux->dst_trampoline))
+		/* got extra prog ref from syscall, or attaching to different prog */
+		bpf_prog_put(prog->aux->dst_prog);
+	if (prog->aux->dst_trampoline && tr != prog->aux->dst_trampoline)
+		/* we allocated a new trampoline, so free the old one */
+		bpf_trampoline_put(prog->aux->dst_trampoline);
+
+	prog->aux->dst_prog = NULL;
+	prog->aux->dst_trampoline = NULL;
+	mutex_unlock(&prog->aux->dst_mutex);
+
+	return bpf_link_settle(&link_primer);
+out_unlock:
+	if (tr && tr != prog->aux->dst_trampoline)
+		bpf_trampoline_put(tr);
+	mutex_unlock(&prog->aux->dst_mutex);
+	kfree(link);
+out_put_prog:
+	if (tgt_prog_fd && tgt_prog)
+		bpf_prog_put(tgt_prog);
+	return err;
+}
+
+struct bpf_raw_tp_link {
+	struct bpf_link link;
+	struct bpf_raw_event_map *btp;
+};
+
+static void bpf_raw_tp_link_release(struct bpf_link *link)
+{
+	struct bpf_raw_tp_link *raw_tp =
+		container_of(link, struct bpf_raw_tp_link, link);
+
+	bpf_probe_unregister(raw_tp->btp, raw_tp->link.prog);
+	bpf_put_raw_tracepoint(raw_tp->btp);
+}
+
+static void bpf_raw_tp_link_dealloc(struct bpf_link *link)
+{
+	struct bpf_raw_tp_link *raw_tp =
+		container_of(link, struct bpf_raw_tp_link, link);
+
+	kfree(raw_tp);
+}
+
+static void bpf_raw_tp_link_show_fdinfo(const struct bpf_link *link,
+					struct seq_file *seq)
+{
+	struct bpf_raw_tp_link *raw_tp_link =
+		container_of(link, struct bpf_raw_tp_link, link);
+
+	seq_printf(seq,
+		   "tp_name:\t%s\n",
+		   raw_tp_link->btp->tp->name);
+}
+
+static int bpf_raw_tp_link_fill_link_info(const struct bpf_link *link,
+					  struct bpf_link_info *info)
+{
+	struct bpf_raw_tp_link *raw_tp_link =
+		container_of(link, struct bpf_raw_tp_link, link);
+	char __user *ubuf = u64_to_user_ptr(info->raw_tracepoint.tp_name);
+	const char *tp_name = raw_tp_link->btp->tp->name;
+	u32 ulen = info->raw_tracepoint.tp_name_len;
+	size_t tp_len = strlen(tp_name);
+
+	if (!ulen ^ !ubuf)
+		return -EINVAL;
+
+	info->raw_tracepoint.tp_name_len = tp_len + 1;
+
+	if (!ubuf)
+		return 0;
+
+	if (ulen >= tp_len + 1) {
+		if (copy_to_user(ubuf, tp_name, tp_len + 1))
+			return -EFAULT;
+	} else {
+		char zero = '\0';
+
+		if (copy_to_user(ubuf, tp_name, ulen - 1))
+			return -EFAULT;
+		if (put_user(zero, ubuf + ulen - 1))
+			return -EFAULT;
+		return -ENOSPC;
+	}
+
+	return 0;
+}
+
+static const struct bpf_link_ops bpf_raw_tp_link_lops = {
+	.release = bpf_raw_tp_link_release,
+	.dealloc = bpf_raw_tp_link_dealloc,
+	.show_fdinfo = bpf_raw_tp_link_show_fdinfo,
+	.fill_link_info = bpf_raw_tp_link_fill_link_info,
+};
+
+#ifdef CONFIG_PERF_EVENTS
+struct bpf_perf_link {
+	struct bpf_link link;
+	struct file *perf_file;
+};
+
+static void bpf_perf_link_release(struct bpf_link *link)
+{
+	struct bpf_perf_link *perf_link = container_of(link, struct bpf_perf_link, link);
+	struct perf_event *event = perf_link->perf_file->private_data;
+
+	perf_event_free_bpf_prog(event);
+	fput(perf_link->perf_file);
+}
+
+static void bpf_perf_link_dealloc(struct bpf_link *link)
+{
+	struct bpf_perf_link *perf_link = container_of(link, struct bpf_perf_link, link);
+
+	kfree(perf_link);
+}
+
+static const struct bpf_link_ops bpf_perf_link_lops = {
+	.release = bpf_perf_link_release,
+	.dealloc = bpf_perf_link_dealloc,
+};
+
+static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
+{
+	struct bpf_link_primer link_primer;
+	struct bpf_perf_link *link;
+	struct perf_event *event;
+	struct file *perf_file;
+	int err;
+
+	if (attr->link_create.flags)
+		return -EINVAL;
+
+	perf_file = perf_event_get(attr->link_create.target_fd);
+	if (IS_ERR(perf_file))
+		return PTR_ERR(perf_file);
+
+	link = kzalloc(sizeof(*link), GFP_USER);
+	if (!link) {
+		err = -ENOMEM;
+		goto out_put_file;
+	}
+	bpf_link_init(&link->link, BPF_LINK_TYPE_PERF_EVENT, &bpf_perf_link_lops, prog);
+	link->perf_file = perf_file;
+
+	err = bpf_link_prime(&link->link, &link_primer);
+	if (err) {
+		kfree(link);
+		goto out_put_file;
+	}
+
+	event = perf_file->private_data;
+	err = perf_event_set_bpf_prog(event, prog, attr->link_create.perf_event.bpf_cookie);
+	if (err) {
+		bpf_link_cleanup(&link_primer);
+		goto out_put_file;
+	}
+	/* perf_event_set_bpf_prog() doesn't take its own refcnt on prog */
+	bpf_prog_inc(prog);
+
+	return bpf_link_settle(&link_primer);
+
+out_put_file:
+	fput(perf_file);
+	return err;
+}
+#else
+static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
+{
+	return -EOPNOTSUPP;
+}
+#endif /* CONFIG_PERF_EVENTS */
+
+static int bpf_raw_tp_link_attach(struct bpf_prog *prog,
+				  const char __user *user_tp_name)
+{
+	struct bpf_link_primer link_primer;
+	struct bpf_raw_tp_link *link;
+	struct bpf_raw_event_map *btp;
+	const char *tp_name;
+	char buf[128];
+	int err;
+
+	switch (prog->type) {
+	case BPF_PROG_TYPE_TRACING:
+	case BPF_PROG_TYPE_EXT:
+	case BPF_PROG_TYPE_LSM:
+		if (user_tp_name)
+			/* The attach point for this category of programs
+			 * should be specified via btf_id during program load.
+			 */
+			return -EINVAL;
+		if (prog->type == BPF_PROG_TYPE_TRACING &&
+		    prog->expected_attach_type == BPF_TRACE_RAW_TP) {
+			tp_name = prog->aux->attach_func_name;
+			break;
+		}
+		return bpf_tracing_prog_attach(prog, 0, 0, 0);
+	case BPF_PROG_TYPE_RAW_TRACEPOINT:
+	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
+		if (strncpy_from_user(buf, user_tp_name, sizeof(buf) - 1) < 0)
+			return -EFAULT;
+		buf[sizeof(buf) - 1] = 0;
+		tp_name = buf;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	btp = bpf_get_raw_tracepoint(tp_name);
+	if (!btp)
+		return -ENOENT;
+
+	link = kzalloc(sizeof(*link), GFP_USER);
+	if (!link) {
+		err = -ENOMEM;
+		goto out_put_btp;
+	}
+	bpf_link_init(&link->link, BPF_LINK_TYPE_RAW_TRACEPOINT,
+		      &bpf_raw_tp_link_lops, prog);
+	link->btp = btp;
+
+	err = bpf_link_prime(&link->link, &link_primer);
+	if (err) {
+		kfree(link);
+		goto out_put_btp;
+	}
+
+	err = bpf_probe_register(link->btp, prog);
+	if (err) {
+		bpf_link_cleanup(&link_primer);
+		goto out_put_btp;
+	}
+
+	return bpf_link_settle(&link_primer);
+
+out_put_btp:
+	bpf_put_raw_tracepoint(btp);
+	return err;
+}
+
+#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd
+
+static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
+{
+	struct bpf_prog *prog;
+	int fd;
+
+	if (CHECK_ATTR(BPF_RAW_TRACEPOINT_OPEN))
+		return -EINVAL;
+
+	prog = bpf_prog_get(attr->raw_tracepoint.prog_fd);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
+	fd = bpf_raw_tp_link_attach(prog, u64_to_user_ptr(attr->raw_tracepoint.name));
+	if (fd < 0)
+		bpf_prog_put(prog);
+	return fd;
+}
+
+static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog,
+					     enum bpf_attach_type attach_type)
+{
+	switch (prog->type) {
+	case BPF_PROG_TYPE_CGROUP_SOCK:
+	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+	case BPF_PROG_TYPE_SK_LOOKUP:
+		return attach_type == prog->expected_attach_type ? 0 : -EINVAL;
+	case BPF_PROG_TYPE_CGROUP_SKB:
+		if (!capable(CAP_NET_ADMIN))
+			/* cg-skb progs can be loaded by unpriv user.
+			 * check permissions at attach time.
+			 */
+			return -EPERM;
+		return prog->enforce_expected_attach_type &&
+			prog->expected_attach_type != attach_type ?
+			-EINVAL : 0;
+	case BPF_PROG_TYPE_KPROBE:
+		if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI &&
+		    attach_type != BPF_TRACE_KPROBE_MULTI)
+			return -EINVAL;
+		return 0;
+	default:
+		return 0;
+	}
+}
+
+static enum bpf_prog_type
+attach_type_to_prog_type(enum bpf_attach_type attach_type)
+{
+	switch (attach_type) {
+	case BPF_CGROUP_INET_INGRESS:
+	case BPF_CGROUP_INET_EGRESS:
+		return BPF_PROG_TYPE_CGROUP_SKB;
+	case BPF_CGROUP_INET_SOCK_CREATE:
+	case BPF_CGROUP_INET_SOCK_RELEASE:
+	case BPF_CGROUP_INET4_POST_BIND:
+	case BPF_CGROUP_INET6_POST_BIND:
+		return BPF_PROG_TYPE_CGROUP_SOCK;
+	case BPF_CGROUP_INET4_BIND:
+	case BPF_CGROUP_INET6_BIND:
+	case BPF_CGROUP_INET4_CONNECT:
+	case BPF_CGROUP_INET6_CONNECT:
+	case BPF_CGROUP_INET4_GETPEERNAME:
+	case BPF_CGROUP_INET6_GETPEERNAME:
+	case BPF_CGROUP_INET4_GETSOCKNAME:
+	case BPF_CGROUP_INET6_GETSOCKNAME:
+	case BPF_CGROUP_UDP4_SENDMSG:
+	case BPF_CGROUP_UDP6_SENDMSG:
+	case BPF_CGROUP_UDP4_RECVMSG:
+	case BPF_CGROUP_UDP6_RECVMSG:
+		return BPF_PROG_TYPE_CGROUP_SOCK_ADDR;
+	case BPF_CGROUP_SOCK_OPS:
+		return BPF_PROG_TYPE_SOCK_OPS;
+	case BPF_CGROUP_DEVICE:
+		return BPF_PROG_TYPE_CGROUP_DEVICE;
+	case BPF_SK_MSG_VERDICT:
+		return BPF_PROG_TYPE_SK_MSG;
+	case BPF_SK_SKB_STREAM_PARSER:
+	case BPF_SK_SKB_STREAM_VERDICT:
+	case BPF_SK_SKB_VERDICT:
+		return BPF_PROG_TYPE_SK_SKB;
+	case BPF_LIRC_MODE2:
+		return BPF_PROG_TYPE_LIRC_MODE2;
+	case BPF_FLOW_DISSECTOR:
+		return BPF_PROG_TYPE_FLOW_DISSECTOR;
+	case BPF_CGROUP_SYSCTL:
+		return BPF_PROG_TYPE_CGROUP_SYSCTL;
+	case BPF_CGROUP_GETSOCKOPT:
+	case BPF_CGROUP_SETSOCKOPT:
+		return BPF_PROG_TYPE_CGROUP_SOCKOPT;
+	case BPF_TRACE_ITER:
+	case BPF_TRACE_RAW_TP:
+	case BPF_TRACE_FENTRY:
+	case BPF_TRACE_FEXIT:
+	case BPF_MODIFY_RETURN:
+		return BPF_PROG_TYPE_TRACING;
+	case BPF_LSM_MAC:
+		return BPF_PROG_TYPE_LSM;
+	case BPF_SK_LOOKUP:
+		return BPF_PROG_TYPE_SK_LOOKUP;
+	case BPF_XDP:
+		return BPF_PROG_TYPE_XDP;
+	case BPF_LSM_CGROUP:
+		return BPF_PROG_TYPE_LSM;
+	default:
+		return BPF_PROG_TYPE_UNSPEC;
+	}
+}
+
+#define BPF_PROG_ATTACH_LAST_FIELD replace_bpf_fd
+
+#define BPF_F_ATTACH_MASK \
+	(BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI | BPF_F_REPLACE)
+
+static int bpf_prog_attach(const union bpf_attr *attr)
+{
+	enum bpf_prog_type ptype;
+	struct bpf_prog *prog;
+	int ret;
+
+	if (CHECK_ATTR(BPF_PROG_ATTACH))
+		return -EINVAL;
+
+	if (attr->attach_flags & ~BPF_F_ATTACH_MASK)
+		return -EINVAL;
+
+	ptype = attach_type_to_prog_type(attr->attach_type);
+	if (ptype == BPF_PROG_TYPE_UNSPEC)
+		return -EINVAL;
+
+	prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
+	if (bpf_prog_attach_check_attach_type(prog, attr->attach_type)) {
+		bpf_prog_put(prog);
+		return -EINVAL;
+	}
+
+	switch (ptype) {
+	case BPF_PROG_TYPE_SK_SKB:
+	case BPF_PROG_TYPE_SK_MSG:
+		ret = sock_map_get_from_fd(attr, prog);
+		break;
+	case BPF_PROG_TYPE_LIRC_MODE2:
+		ret = lirc_prog_attach(attr, prog);
+		break;
+	case BPF_PROG_TYPE_FLOW_DISSECTOR:
+		ret = netns_bpf_prog_attach(attr, prog);
+		break;
+	case BPF_PROG_TYPE_CGROUP_DEVICE:
+	case BPF_PROG_TYPE_CGROUP_SKB:
+	case BPF_PROG_TYPE_CGROUP_SOCK:
+	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+	case BPF_PROG_TYPE_CGROUP_SYSCTL:
+	case BPF_PROG_TYPE_SOCK_OPS:
+	case BPF_PROG_TYPE_LSM:
+		if (ptype == BPF_PROG_TYPE_LSM &&
+		    prog->expected_attach_type != BPF_LSM_CGROUP)
+			ret = -EINVAL;
+		else
+			ret = cgroup_bpf_prog_attach(attr, ptype, prog);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	if (ret)
+		bpf_prog_put(prog);
+	return ret;
+}
+
+#define BPF_PROG_DETACH_LAST_FIELD attach_type
+
+static int bpf_prog_detach(const union bpf_attr *attr)
+{
+	enum bpf_prog_type ptype;
+
+	if (CHECK_ATTR(BPF_PROG_DETACH))
+		return -EINVAL;
+
+	ptype = attach_type_to_prog_type(attr->attach_type);
+
+	switch (ptype) {
+	case BPF_PROG_TYPE_SK_MSG:
+	case BPF_PROG_TYPE_SK_SKB:
+		return sock_map_prog_detach(attr, ptype);
+	case BPF_PROG_TYPE_LIRC_MODE2:
+		return lirc_prog_detach(attr);
+	case BPF_PROG_TYPE_FLOW_DISSECTOR:
+		return netns_bpf_prog_detach(attr, ptype);
+	case BPF_PROG_TYPE_CGROUP_DEVICE:
+	case BPF_PROG_TYPE_CGROUP_SKB:
+	case BPF_PROG_TYPE_CGROUP_SOCK:
+	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+	case BPF_PROG_TYPE_CGROUP_SYSCTL:
+	case BPF_PROG_TYPE_SOCK_OPS:
+	case BPF_PROG_TYPE_LSM:
+		return cgroup_bpf_prog_detach(attr, ptype);
+	default:
+		return -EINVAL;
+	}
+}
+
+#define BPF_PROG_QUERY_LAST_FIELD query.prog_attach_flags
+
+static int bpf_prog_query(const union bpf_attr *attr,
+			  union bpf_attr __user *uattr)
+{
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+	if (CHECK_ATTR(BPF_PROG_QUERY))
+		return -EINVAL;
+	if (attr->query.query_flags & ~BPF_F_QUERY_EFFECTIVE)
+		return -EINVAL;
+
+	switch (attr->query.attach_type) {
+	case BPF_CGROUP_INET_INGRESS:
+	case BPF_CGROUP_INET_EGRESS:
+	case BPF_CGROUP_INET_SOCK_CREATE:
+	case BPF_CGROUP_INET_SOCK_RELEASE:
+	case BPF_CGROUP_INET4_BIND:
+	case BPF_CGROUP_INET6_BIND:
+	case BPF_CGROUP_INET4_POST_BIND:
+	case BPF_CGROUP_INET6_POST_BIND:
+	case BPF_CGROUP_INET4_CONNECT:
+	case BPF_CGROUP_INET6_CONNECT:
+	case BPF_CGROUP_INET4_GETPEERNAME:
+	case BPF_CGROUP_INET6_GETPEERNAME:
+	case BPF_CGROUP_INET4_GETSOCKNAME:
+	case BPF_CGROUP_INET6_GETSOCKNAME:
+	case BPF_CGROUP_UDP4_SENDMSG:
+	case BPF_CGROUP_UDP6_SENDMSG:
+	case BPF_CGROUP_UDP4_RECVMSG:
+	case BPF_CGROUP_UDP6_RECVMSG:
+	case BPF_CGROUP_SOCK_OPS:
+	case BPF_CGROUP_DEVICE:
+	case BPF_CGROUP_SYSCTL:
+	case BPF_CGROUP_GETSOCKOPT:
+	case BPF_CGROUP_SETSOCKOPT:
+	case BPF_LSM_CGROUP:
+		return cgroup_bpf_prog_query(attr, uattr);
+	case BPF_LIRC_MODE2:
+		return lirc_prog_query(attr, uattr);
+	case BPF_FLOW_DISSECTOR:
+	case BPF_SK_LOOKUP:
+		return netns_bpf_prog_query(attr, uattr);
+	case BPF_SK_SKB_STREAM_PARSER:
+	case BPF_SK_SKB_STREAM_VERDICT:
+	case BPF_SK_MSG_VERDICT:
+	case BPF_SK_SKB_VERDICT:
+		return sock_map_bpf_prog_query(attr, uattr);
+	default:
+		return -EINVAL;
+	}
+}
+
+#define BPF_PROG_TEST_RUN_LAST_FIELD test.batch_size
+
+static int bpf_prog_test_run(const union bpf_attr *attr,
+			     union bpf_attr __user *uattr)
+{
+	struct bpf_prog *prog;
+	int ret = -ENOTSUPP;
+
+	if (CHECK_ATTR(BPF_PROG_TEST_RUN))
+		return -EINVAL;
+
+	if ((attr->test.ctx_size_in && !attr->test.ctx_in) ||
+	    (!attr->test.ctx_size_in && attr->test.ctx_in))
+		return -EINVAL;
+
+	if ((attr->test.ctx_size_out && !attr->test.ctx_out) ||
+	    (!attr->test.ctx_size_out && attr->test.ctx_out))
+		return -EINVAL;
+
+	prog = bpf_prog_get(attr->test.prog_fd);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
+	if (prog->aux->ops->test_run)
+		ret = prog->aux->ops->test_run(prog, attr, uattr);
+
+	bpf_prog_put(prog);
+	return ret;
+}
+
+#define BPF_OBJ_GET_NEXT_ID_LAST_FIELD next_id
+
+static int bpf_obj_get_next_id(const union bpf_attr *attr,
+			       union bpf_attr __user *uattr,
+			       struct idr *idr,
+			       spinlock_t *lock)
+{
+	u32 next_id = attr->start_id;
+	int err = 0;
+
+	if (CHECK_ATTR(BPF_OBJ_GET_NEXT_ID) || next_id >= INT_MAX)
+		return -EINVAL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	next_id++;
+	spin_lock_bh(lock);
+	if (!idr_get_next(idr, &next_id))
+		err = -ENOENT;
+	spin_unlock_bh(lock);
+
+	if (!err)
+		err = put_user(next_id, &uattr->next_id);
+
+	return err;
+}
+
+struct bpf_map *bpf_map_get_curr_or_next(u32 *id)
+{
+	struct bpf_map *map;
+
+	spin_lock_bh(&map_idr_lock);
+again:
+	map = idr_get_next(&map_idr, id);
+	if (map) {
+		map = __bpf_map_inc_not_zero(map, false);
+		if (IS_ERR(map)) {
+			(*id)++;
+			goto again;
+		}
+	}
+	spin_unlock_bh(&map_idr_lock);
+
+	return map;
+}
+
+struct bpf_prog *bpf_prog_get_curr_or_next(u32 *id)
+{
+	struct bpf_prog *prog;
+
+	spin_lock_bh(&prog_idr_lock);
+again:
+	prog = idr_get_next(&prog_idr, id);
+	if (prog) {
+		prog = bpf_prog_inc_not_zero(prog);
+		if (IS_ERR(prog)) {
+			(*id)++;
+			goto again;
+		}
+	}
+	spin_unlock_bh(&prog_idr_lock);
+
+	return prog;
+}
+
+#define BPF_PROG_GET_FD_BY_ID_LAST_FIELD prog_id
+
+struct bpf_prog *bpf_prog_by_id(u32 id)
+{
+	struct bpf_prog *prog;
+
+	if (!id)
+		return ERR_PTR(-ENOENT);
+
+	spin_lock_bh(&prog_idr_lock);
+	prog = idr_find(&prog_idr, id);
+	if (prog)
+		prog = bpf_prog_inc_not_zero(prog);
+	else
+		prog = ERR_PTR(-ENOENT);
+	spin_unlock_bh(&prog_idr_lock);
+	return prog;
+}
+
+static int bpf_prog_get_fd_by_id(const union bpf_attr *attr)
+{
+	struct bpf_prog *prog;
+	u32 id = attr->prog_id;
+	int fd;
+
+	if (CHECK_ATTR(BPF_PROG_GET_FD_BY_ID))
+		return -EINVAL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	prog = bpf_prog_by_id(id);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
+	fd = bpf_prog_new_fd(prog);
+	if (fd < 0)
+		bpf_prog_put(prog);
+
+	return fd;
+}
+
+#define BPF_MAP_GET_FD_BY_ID_LAST_FIELD open_flags
+
+static int bpf_map_get_fd_by_id(const union bpf_attr *attr)
+{
+	struct bpf_map *map;
+	u32 id = attr->map_id;
+	int f_flags;
+	int fd;
+
+	if (CHECK_ATTR(BPF_MAP_GET_FD_BY_ID) ||
+	    attr->open_flags & ~BPF_OBJ_FLAG_MASK)
+		return -EINVAL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	f_flags = bpf_get_file_flag(attr->open_flags);
+	if (f_flags < 0)
+		return f_flags;
+
+	spin_lock_bh(&map_idr_lock);
+	map = idr_find(&map_idr, id);
+	if (map)
+		map = __bpf_map_inc_not_zero(map, true);
+	else
+		map = ERR_PTR(-ENOENT);
+	spin_unlock_bh(&map_idr_lock);
+
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+
+	fd = bpf_map_new_fd(map, f_flags);
+	if (fd < 0)
+		bpf_map_put_with_uref(map);
+
+	return fd;
+}
+
+static const struct bpf_map *bpf_map_from_imm(const struct bpf_prog *prog,
+					      unsigned long addr, u32 *off,
+					      u32 *type)
+{
+	const struct bpf_map *map;
+	int i;
+
+	mutex_lock(&prog->aux->used_maps_mutex);
+	for (i = 0, *off = 0; i < prog->aux->used_map_cnt; i++) {
+		map = prog->aux->used_maps[i];
+		if (map == (void *)addr) {
+			*type = BPF_PSEUDO_MAP_FD;
+			goto out;
+		}
+		if (!map->ops->map_direct_value_meta)
+			continue;
+		if (!map->ops->map_direct_value_meta(map, addr, off)) {
+			*type = BPF_PSEUDO_MAP_VALUE;
+			goto out;
+		}
+	}
+	map = NULL;
+
+out:
+	mutex_unlock(&prog->aux->used_maps_mutex);
+	return map;
+}
+
+static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog,
+					      const struct cred *f_cred)
+{
+	const struct bpf_map *map;
+	struct bpf_insn *insns;
+	u32 off, type;
+	u64 imm;
+	u8 code;
+	int i;
+
+	insns = kmemdup(prog->insnsi, bpf_prog_insn_size(prog),
+			GFP_USER);
+	if (!insns)
+		return insns;
+
+	for (i = 0; i < prog->len; i++) {
+		code = insns[i].code;
+
+		if (code == (BPF_JMP | BPF_TAIL_CALL)) {
+			insns[i].code = BPF_JMP | BPF_CALL;
+			insns[i].imm = BPF_FUNC_tail_call;
+			/* fall-through */
+		}
+		if (code == (BPF_JMP | BPF_CALL) ||
+		    code == (BPF_JMP | BPF_CALL_ARGS)) {
+			if (code == (BPF_JMP | BPF_CALL_ARGS))
+				insns[i].code = BPF_JMP | BPF_CALL;
+			if (!bpf_dump_raw_ok(f_cred))
+				insns[i].imm = 0;
+			continue;
+		}
+		if (BPF_CLASS(code) == BPF_LDX && BPF_MODE(code) == BPF_PROBE_MEM) {
+			insns[i].code = BPF_LDX | BPF_SIZE(code) | BPF_MEM;
+			continue;
+		}
+
+		if (code != (BPF_LD | BPF_IMM | BPF_DW))
+			continue;
+
+		imm = ((u64)insns[i + 1].imm << 32) | (u32)insns[i].imm;
+		map = bpf_map_from_imm(prog, imm, &off, &type);
+		if (map) {
+			insns[i].src_reg = type;
+			insns[i].imm = map->id;
+			insns[i + 1].imm = off;
+			continue;
+		}
+	}
+
+	return insns;
+}
+
+static int set_info_rec_size(struct bpf_prog_info *info)
+{
+	/*
+	 * Ensure info.*_rec_size is the same as kernel expected size
+	 *
+	 * or
+	 *
+	 * Only allow zero *_rec_size if both _rec_size and _cnt are
+	 * zero.  In this case, the kernel will set the expected
+	 * _rec_size back to the info.
+	 */
+
+	if ((info->nr_func_info || info->func_info_rec_size) &&
+	    info->func_info_rec_size != sizeof(struct bpf_func_info))
+		return -EINVAL;
+
+	if ((info->nr_line_info || info->line_info_rec_size) &&
+	    info->line_info_rec_size != sizeof(struct bpf_line_info))
+		return -EINVAL;
+
+	if ((info->nr_jited_line_info || info->jited_line_info_rec_size) &&
+	    info->jited_line_info_rec_size != sizeof(__u64))
+		return -EINVAL;
+
+	info->func_info_rec_size = sizeof(struct bpf_func_info);
+	info->line_info_rec_size = sizeof(struct bpf_line_info);
+	info->jited_line_info_rec_size = sizeof(__u64);
+
+	return 0;
+}
+
+static int bpf_prog_get_info_by_fd(struct file *file,
+				   struct bpf_prog *prog,
+				   const union bpf_attr *attr,
+				   union bpf_attr __user *uattr)
+{
+	struct bpf_prog_info __user *uinfo = u64_to_user_ptr(attr->info.info);
+	struct btf *attach_btf = bpf_prog_get_target_btf(prog);
+	struct bpf_prog_info info;
+	u32 info_len = attr->info.info_len;
+	struct bpf_prog_kstats stats;
+	char __user *uinsns;
+	u32 ulen;
+	int err;
+
+	err = bpf_check_uarg_tail_zero(USER_BPFPTR(uinfo), sizeof(info), info_len);
+	if (err)
+		return err;
+	info_len = min_t(u32, sizeof(info), info_len);
+
+	memset(&info, 0, sizeof(info));
+	if (copy_from_user(&info, uinfo, info_len))
+		return -EFAULT;
+
+	info.type = prog->type;
+	info.id = prog->aux->id;
+	info.load_time = prog->aux->load_time;
+	info.created_by_uid = from_kuid_munged(current_user_ns(),
+					       prog->aux->user->uid);
+	info.gpl_compatible = prog->gpl_compatible;
+
+	memcpy(info.tag, prog->tag, sizeof(prog->tag));
+	memcpy(info.name, prog->aux->name, sizeof(prog->aux->name));
+
+	mutex_lock(&prog->aux->used_maps_mutex);
+	ulen = info.nr_map_ids;
+	info.nr_map_ids = prog->aux->used_map_cnt;
+	ulen = min_t(u32, info.nr_map_ids, ulen);
+	if (ulen) {
+		u32 __user *user_map_ids = u64_to_user_ptr(info.map_ids);
+		u32 i;
+
+		for (i = 0; i < ulen; i++)
+			if (put_user(prog->aux->used_maps[i]->id,
+				     &user_map_ids[i])) {
+				mutex_unlock(&prog->aux->used_maps_mutex);
+				return -EFAULT;
+			}
+	}
+	mutex_unlock(&prog->aux->used_maps_mutex);
+
+	err = set_info_rec_size(&info);
+	if (err)
+		return err;
+
+	bpf_prog_get_stats(prog, &stats);
+	info.run_time_ns = stats.nsecs;
+	info.run_cnt = stats.cnt;
+	info.recursion_misses = stats.misses;
+
+	info.verified_insns = prog->aux->verified_insns;
+
+	if (!bpf_capable()) {
+		info.jited_prog_len = 0;
+		info.xlated_prog_len = 0;
+		info.nr_jited_ksyms = 0;
+		info.nr_jited_func_lens = 0;
+		info.nr_func_info = 0;
+		info.nr_line_info = 0;
+		info.nr_jited_line_info = 0;
+		goto done;
+	}
+
+	ulen = info.xlated_prog_len;
+	info.xlated_prog_len = bpf_prog_insn_size(prog);
+	if (info.xlated_prog_len && ulen) {
+		struct bpf_insn *insns_sanitized;
+		bool fault;
+
+		if (prog->blinded && !bpf_dump_raw_ok(file->f_cred)) {
+			info.xlated_prog_insns = 0;
+			goto done;
+		}
+		insns_sanitized = bpf_insn_prepare_dump(prog, file->f_cred);
+		if (!insns_sanitized)
+			return -ENOMEM;
+		uinsns = u64_to_user_ptr(info.xlated_prog_insns);
+		ulen = min_t(u32, info.xlated_prog_len, ulen);
+		fault = copy_to_user(uinsns, insns_sanitized, ulen);
+		kfree(insns_sanitized);
+		if (fault)
+			return -EFAULT;
+	}
+
+	if (bpf_prog_is_dev_bound(prog->aux)) {
+		err = bpf_prog_offload_info_fill(&info, prog);
+		if (err)
+			return err;
+		goto done;
+	}
+
+	/* NOTE: the following code is supposed to be skipped for offload.
+	 * bpf_prog_offload_info_fill() is the place to fill similar fields
+	 * for offload.
+	 */
+	ulen = info.jited_prog_len;
+	if (prog->aux->func_cnt) {
+		u32 i;
+
+		info.jited_prog_len = 0;
+		for (i = 0; i < prog->aux->func_cnt; i++)
+			info.jited_prog_len += prog->aux->func[i]->jited_len;
+	} else {
+		info.jited_prog_len = prog->jited_len;
+	}
+
+	if (info.jited_prog_len && ulen) {
+		if (bpf_dump_raw_ok(file->f_cred)) {
+			uinsns = u64_to_user_ptr(info.jited_prog_insns);
+			ulen = min_t(u32, info.jited_prog_len, ulen);
+
+			/* for multi-function programs, copy the JITed
+			 * instructions for all the functions
+			 */
+			if (prog->aux->func_cnt) {
+				u32 len, free, i;
+				u8 *img;
+
+				free = ulen;
+				for (i = 0; i < prog->aux->func_cnt; i++) {
+					len = prog->aux->func[i]->jited_len;
+					len = min_t(u32, len, free);
+					img = (u8 *) prog->aux->func[i]->bpf_func;
+					if (copy_to_user(uinsns, img, len))
+						return -EFAULT;
+					uinsns += len;
+					free -= len;
+					if (!free)
+						break;
+				}
+			} else {
+				if (copy_to_user(uinsns, prog->bpf_func, ulen))
+					return -EFAULT;
+			}
+		} else {
+			info.jited_prog_insns = 0;
+		}
+	}
+
+	ulen = info.nr_jited_ksyms;
+	info.nr_jited_ksyms = prog->aux->func_cnt ? : 1;
+	if (ulen) {
+		if (bpf_dump_raw_ok(file->f_cred)) {
+			unsigned long ksym_addr;
+			u64 __user *user_ksyms;
+			u32 i;
+
+			/* copy the address of the kernel symbol
+			 * corresponding to each function
+			 */
+			ulen = min_t(u32, info.nr_jited_ksyms, ulen);
+			user_ksyms = u64_to_user_ptr(info.jited_ksyms);
+			if (prog->aux->func_cnt) {
+				for (i = 0; i < ulen; i++) {
+					ksym_addr = (unsigned long)
+						prog->aux->func[i]->bpf_func;
+					if (put_user((u64) ksym_addr,
+						     &user_ksyms[i]))
+						return -EFAULT;
+				}
+			} else {
+				ksym_addr = (unsigned long) prog->bpf_func;
+				if (put_user((u64) ksym_addr, &user_ksyms[0]))
+					return -EFAULT;
+			}
+		} else {
+			info.jited_ksyms = 0;
+		}
+	}
+
+	ulen = info.nr_jited_func_lens;
+	info.nr_jited_func_lens = prog->aux->func_cnt ? : 1;
+	if (ulen) {
+		if (bpf_dump_raw_ok(file->f_cred)) {
+			u32 __user *user_lens;
+			u32 func_len, i;
+
+			/* copy the JITed image lengths for each function */
+			ulen = min_t(u32, info.nr_jited_func_lens, ulen);
+			user_lens = u64_to_user_ptr(info.jited_func_lens);
+			if (prog->aux->func_cnt) {
+				for (i = 0; i < ulen; i++) {
+					func_len =
+						prog->aux->func[i]->jited_len;
+					if (put_user(func_len, &user_lens[i]))
+						return -EFAULT;
+				}
+			} else {
+				func_len = prog->jited_len;
+				if (put_user(func_len, &user_lens[0]))
+					return -EFAULT;
+			}
+		} else {
+			info.jited_func_lens = 0;
+		}
+	}
+
+	if (prog->aux->btf)
+		info.btf_id = btf_obj_id(prog->aux->btf);
+	info.attach_btf_id = prog->aux->attach_btf_id;
+	if (attach_btf)
+		info.attach_btf_obj_id = btf_obj_id(attach_btf);
+
+	ulen = info.nr_func_info;
+	info.nr_func_info = prog->aux->func_info_cnt;
+	if (info.nr_func_info && ulen) {
+		char __user *user_finfo;
+
+		user_finfo = u64_to_user_ptr(info.func_info);
+		ulen = min_t(u32, info.nr_func_info, ulen);
+		if (copy_to_user(user_finfo, prog->aux->func_info,
+				 info.func_info_rec_size * ulen))
+			return -EFAULT;
+	}
+
+	ulen = info.nr_line_info;
+	info.nr_line_info = prog->aux->nr_linfo;
+	if (info.nr_line_info && ulen) {
+		__u8 __user *user_linfo;
+
+		user_linfo = u64_to_user_ptr(info.line_info);
+		ulen = min_t(u32, info.nr_line_info, ulen);
+		if (copy_to_user(user_linfo, prog->aux->linfo,
+				 info.line_info_rec_size * ulen))
+			return -EFAULT;
+	}
+
+	ulen = info.nr_jited_line_info;
+	if (prog->aux->jited_linfo)
+		info.nr_jited_line_info = prog->aux->nr_linfo;
+	else
+		info.nr_jited_line_info = 0;
+	if (info.nr_jited_line_info && ulen) {
+		if (bpf_dump_raw_ok(file->f_cred)) {
+			unsigned long line_addr;
+			__u64 __user *user_linfo;
+			u32 i;
+
+			user_linfo = u64_to_user_ptr(info.jited_line_info);
+			ulen = min_t(u32, info.nr_jited_line_info, ulen);
+			for (i = 0; i < ulen; i++) {
+				line_addr = (unsigned long)prog->aux->jited_linfo[i];
+				if (put_user((__u64)line_addr, &user_linfo[i]))
+					return -EFAULT;
+			}
+		} else {
+			info.jited_line_info = 0;
+		}
+	}
+
+	ulen = info.nr_prog_tags;
+	info.nr_prog_tags = prog->aux->func_cnt ? : 1;
+	if (ulen) {
+		__u8 __user (*user_prog_tags)[BPF_TAG_SIZE];
+		u32 i;
+
+		user_prog_tags = u64_to_user_ptr(info.prog_tags);
+		ulen = min_t(u32, info.nr_prog_tags, ulen);
+		if (prog->aux->func_cnt) {
+			for (i = 0; i < ulen; i++) {
+				if (copy_to_user(user_prog_tags[i],
+						 prog->aux->func[i]->tag,
+						 BPF_TAG_SIZE))
+					return -EFAULT;
+			}
+		} else {
+			if (copy_to_user(user_prog_tags[0],
+					 prog->tag, BPF_TAG_SIZE))
+				return -EFAULT;
+		}
+	}
+
+done:
+	if (copy_to_user(uinfo, &info, info_len) ||
+	    put_user(info_len, &uattr->info.info_len))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int bpf_map_get_info_by_fd(struct file *file,
+				  struct bpf_map *map,
+				  const union bpf_attr *attr,
+				  union bpf_attr __user *uattr)
+{
+	struct bpf_map_info __user *uinfo = u64_to_user_ptr(attr->info.info);
+	struct bpf_map_info info;
+	u32 info_len = attr->info.info_len;
+	int err;
+
+	err = bpf_check_uarg_tail_zero(USER_BPFPTR(uinfo), sizeof(info), info_len);
+	if (err)
+		return err;
+	info_len = min_t(u32, sizeof(info), info_len);
+
+	memset(&info, 0, sizeof(info));
+	info.type = map->map_type;
+	info.id = map->id;
+	info.key_size = map->key_size;
+	info.value_size = map->value_size;
+	info.max_entries = map->max_entries;
+	info.map_flags = map->map_flags;
+	info.map_extra = map->map_extra;
+	memcpy(info.name, map->name, sizeof(map->name));
+
+	if (map->btf) {
+		info.btf_id = btf_obj_id(map->btf);
+		info.btf_key_type_id = map->btf_key_type_id;
+		info.btf_value_type_id = map->btf_value_type_id;
+	}
+	info.btf_vmlinux_value_type_id = map->btf_vmlinux_value_type_id;
+
+	if (bpf_map_is_dev_bound(map)) {
+		err = bpf_map_offload_info_fill(&info, map);
+		if (err)
+			return err;
+	}
+
+	if (copy_to_user(uinfo, &info, info_len) ||
+	    put_user(info_len, &uattr->info.info_len))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int bpf_btf_get_info_by_fd(struct file *file,
+				  struct btf *btf,
+				  const union bpf_attr *attr,
+				  union bpf_attr __user *uattr)
+{
+	struct bpf_btf_info __user *uinfo = u64_to_user_ptr(attr->info.info);
+	u32 info_len = attr->info.info_len;
+	int err;
+
+	err = bpf_check_uarg_tail_zero(USER_BPFPTR(uinfo), sizeof(*uinfo), info_len);
+	if (err)
+		return err;
+
+	return btf_get_info_by_fd(btf, attr, uattr);
+}
+
+static int bpf_link_get_info_by_fd(struct file *file,
+				  struct bpf_link *link,
+				  const union bpf_attr *attr,
+				  union bpf_attr __user *uattr)
+{
+	struct bpf_link_info __user *uinfo = u64_to_user_ptr(attr->info.info);
+	struct bpf_link_info info;
+	u32 info_len = attr->info.info_len;
+	int err;
+
+	err = bpf_check_uarg_tail_zero(USER_BPFPTR(uinfo), sizeof(info), info_len);
+	if (err)
+		return err;
+	info_len = min_t(u32, sizeof(info), info_len);
+
+	memset(&info, 0, sizeof(info));
+	if (copy_from_user(&info, uinfo, info_len))
+		return -EFAULT;
+
+	info.type = link->type;
+	info.id = link->id;
+	info.prog_id = link->prog->aux->id;
+
+	if (link->ops->fill_link_info) {
+		err = link->ops->fill_link_info(link, &info);
+		if (err)
+			return err;
+	}
+
+	if (copy_to_user(uinfo, &info, info_len) ||
+	    put_user(info_len, &uattr->info.info_len))
+		return -EFAULT;
+
+	return 0;
+}
+
+
+#define BPF_OBJ_GET_INFO_BY_FD_LAST_FIELD info.info
+
+static int bpf_obj_get_info_by_fd(const union bpf_attr *attr,
+				  union bpf_attr __user *uattr)
+{
+	int ufd = attr->info.bpf_fd;
+	struct fd f;
+	int err;
+
+	if (CHECK_ATTR(BPF_OBJ_GET_INFO_BY_FD))
+		return -EINVAL;
+
+	f = fdget(ufd);
+	if (!f.file)
+		return -EBADFD;
+
+	if (f.file->f_op == &bpf_prog_fops)
+		err = bpf_prog_get_info_by_fd(f.file, f.file->private_data, attr,
+					      uattr);
+	else if (f.file->f_op == &bpf_map_fops)
+		err = bpf_map_get_info_by_fd(f.file, f.file->private_data, attr,
+					     uattr);
+	else if (f.file->f_op == &btf_fops)
+		err = bpf_btf_get_info_by_fd(f.file, f.file->private_data, attr, uattr);
+	else if (f.file->f_op == &bpf_link_fops)
+		err = bpf_link_get_info_by_fd(f.file, f.file->private_data,
+					      attr, uattr);
+	else
+		err = -EINVAL;
+
+	fdput(f);
+	return err;
+}
+
+#define BPF_BTF_LOAD_LAST_FIELD btf_log_level
+
+static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr)
+{
+	if (CHECK_ATTR(BPF_BTF_LOAD))
+		return -EINVAL;
+
+	if (!bpf_capable())
+		return -EPERM;
+
+	return btf_new_fd(attr, uattr);
+}
+
+#define BPF_BTF_GET_FD_BY_ID_LAST_FIELD btf_id
+
+static int bpf_btf_get_fd_by_id(const union bpf_attr *attr)
+{
+	if (CHECK_ATTR(BPF_BTF_GET_FD_BY_ID))
+		return -EINVAL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	return btf_get_fd_by_id(attr->btf_id);
+}
+
+static int bpf_task_fd_query_copy(const union bpf_attr *attr,
+				    union bpf_attr __user *uattr,
+				    u32 prog_id, u32 fd_type,
+				    const char *buf, u64 probe_offset,
+				    u64 probe_addr)
+{
+	char __user *ubuf = u64_to_user_ptr(attr->task_fd_query.buf);
+	u32 len = buf ? strlen(buf) : 0, input_len;
+	int err = 0;
+
+	if (put_user(len, &uattr->task_fd_query.buf_len))
+		return -EFAULT;
+	input_len = attr->task_fd_query.buf_len;
+	if (input_len && ubuf) {
+		if (!len) {
+			/* nothing to copy, just make ubuf NULL terminated */
+			char zero = '\0';
+
+			if (put_user(zero, ubuf))
+				return -EFAULT;
+		} else if (input_len >= len + 1) {
+			/* ubuf can hold the string with NULL terminator */
+			if (copy_to_user(ubuf, buf, len + 1))
+				return -EFAULT;
+		} else {
+			/* ubuf cannot hold the string with NULL terminator,
+			 * do a partial copy with NULL terminator.
+			 */
+			char zero = '\0';
+
+			err = -ENOSPC;
+			if (copy_to_user(ubuf, buf, input_len - 1))
+				return -EFAULT;
+			if (put_user(zero, ubuf + input_len - 1))
+				return -EFAULT;
+		}
+	}
+
+	if (put_user(prog_id, &uattr->task_fd_query.prog_id) ||
+	    put_user(fd_type, &uattr->task_fd_query.fd_type) ||
+	    put_user(probe_offset, &uattr->task_fd_query.probe_offset) ||
+	    put_user(probe_addr, &uattr->task_fd_query.probe_addr))
+		return -EFAULT;
+
+	return err;
+}
+
+#define BPF_TASK_FD_QUERY_LAST_FIELD task_fd_query.probe_addr
+
+static int bpf_task_fd_query(const union bpf_attr *attr,
+			     union bpf_attr __user *uattr)
+{
+	pid_t pid = attr->task_fd_query.pid;
+	u32 fd = attr->task_fd_query.fd;
+	const struct perf_event *event;
+	struct task_struct *task;
+	struct file *file;
+	int err;
+
+	if (CHECK_ATTR(BPF_TASK_FD_QUERY))
+		return -EINVAL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (attr->task_fd_query.flags != 0)
+		return -EINVAL;
+
+	rcu_read_lock();
+	task = get_pid_task(find_vpid(pid), PIDTYPE_PID);
+	rcu_read_unlock();
+	if (!task)
+		return -ENOENT;
+
+	err = 0;
+	file = fget_task(task, fd);
+	put_task_struct(task);
+	if (!file)
+		return -EBADF;
+
+	if (file->f_op == &bpf_link_fops) {
+		struct bpf_link *link = file->private_data;
+
+		if (link->ops == &bpf_raw_tp_link_lops) {
+			struct bpf_raw_tp_link *raw_tp =
+				container_of(link, struct bpf_raw_tp_link, link);
+			struct bpf_raw_event_map *btp = raw_tp->btp;
+
+			err = bpf_task_fd_query_copy(attr, uattr,
+						     raw_tp->link.prog->aux->id,
+						     BPF_FD_TYPE_RAW_TRACEPOINT,
+						     btp->tp->name, 0, 0);
+			goto put_file;
+		}
+		goto out_not_supp;
+	}
+
+	event = perf_get_event(file);
+	if (!IS_ERR(event)) {
+		u64 probe_offset, probe_addr;
+		u32 prog_id, fd_type;
+		const char *buf;
+
+		err = bpf_get_perf_event_info(event, &prog_id, &fd_type,
+					      &buf, &probe_offset,
+					      &probe_addr);
+		if (!err)
+			err = bpf_task_fd_query_copy(attr, uattr, prog_id,
+						     fd_type, buf,
+						     probe_offset,
+						     probe_addr);
+		goto put_file;
+	}
+
+out_not_supp:
+	err = -ENOTSUPP;
+put_file:
+	fput(file);
+	return err;
+}
+
+#define BPF_MAP_BATCH_LAST_FIELD batch.flags
+
+#define BPF_DO_BATCH(fn)			\
+	do {					\
+		if (!fn) {			\
+			err = -ENOTSUPP;	\
+			goto err_put;		\
+		}				\
+		err = fn(map, attr, uattr);	\
+	} while (0)
+
+static int bpf_map_do_batch(const union bpf_attr *attr,
+			    union bpf_attr __user *uattr,
+			    int cmd)
+{
+	bool has_read  = cmd == BPF_MAP_LOOKUP_BATCH ||
+			 cmd == BPF_MAP_LOOKUP_AND_DELETE_BATCH;
+	bool has_write = cmd != BPF_MAP_LOOKUP_BATCH;
+	struct bpf_map *map;
+	int err, ufd;
+	struct fd f;
+
+	if (CHECK_ATTR(BPF_MAP_BATCH))
+		return -EINVAL;
+
+	ufd = attr->batch.map_fd;
+	f = fdget(ufd);
+	map = __bpf_map_get(f);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+	if (has_write)
+		bpf_map_write_active_inc(map);
+	if (has_read && !(map_get_sys_perms(map, f) & FMODE_CAN_READ)) {
+		err = -EPERM;
+		goto err_put;
+	}
+	if (has_write && !(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
+		err = -EPERM;
+		goto err_put;
+	}
+
+	if (cmd == BPF_MAP_LOOKUP_BATCH)
+		BPF_DO_BATCH(map->ops->map_lookup_batch);
+	else if (cmd == BPF_MAP_LOOKUP_AND_DELETE_BATCH)
+		BPF_DO_BATCH(map->ops->map_lookup_and_delete_batch);
+	else if (cmd == BPF_MAP_UPDATE_BATCH)
+		BPF_DO_BATCH(map->ops->map_update_batch);
+	else
+		BPF_DO_BATCH(map->ops->map_delete_batch);
+err_put:
+	if (has_write)
+		bpf_map_write_active_dec(map);
+	fdput(f);
+	return err;
+}
+
+#define BPF_LINK_CREATE_LAST_FIELD link_create.kprobe_multi.cookies
+static int link_create(union bpf_attr *attr, bpfptr_t uattr)
+{
+	enum bpf_prog_type ptype;
+	struct bpf_prog *prog;
+	int ret;
+
+	if (CHECK_ATTR(BPF_LINK_CREATE))
+		return -EINVAL;
+
+	prog = bpf_prog_get(attr->link_create.prog_fd);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
+	ret = bpf_prog_attach_check_attach_type(prog,
+						attr->link_create.attach_type);
+	if (ret)
+		goto out;
+
+	switch (prog->type) {
+	case BPF_PROG_TYPE_EXT:
+		break;
+	case BPF_PROG_TYPE_PERF_EVENT:
+	case BPF_PROG_TYPE_TRACEPOINT:
+		if (attr->link_create.attach_type != BPF_PERF_EVENT) {
+			ret = -EINVAL;
+			goto out;
+		}
+		break;
+	case BPF_PROG_TYPE_KPROBE:
+		if (attr->link_create.attach_type != BPF_PERF_EVENT &&
+		    attr->link_create.attach_type != BPF_TRACE_KPROBE_MULTI) {
+			ret = -EINVAL;
+			goto out;
+		}
+		break;
+	default:
+		ptype = attach_type_to_prog_type(attr->link_create.attach_type);
+		if (ptype == BPF_PROG_TYPE_UNSPEC || ptype != prog->type) {
+			ret = -EINVAL;
+			goto out;
+		}
+		break;
+	}
+
+	switch (prog->type) {
+	case BPF_PROG_TYPE_CGROUP_SKB:
+	case BPF_PROG_TYPE_CGROUP_SOCK:
+	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+	case BPF_PROG_TYPE_SOCK_OPS:
+	case BPF_PROG_TYPE_CGROUP_DEVICE:
+	case BPF_PROG_TYPE_CGROUP_SYSCTL:
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+		ret = cgroup_bpf_link_attach(attr, prog);
+		break;
+	case BPF_PROG_TYPE_EXT:
+		ret = bpf_tracing_prog_attach(prog,
+					      attr->link_create.target_fd,
+					      attr->link_create.target_btf_id,
+					      attr->link_create.tracing.cookie);
+		break;
+	case BPF_PROG_TYPE_LSM:
+	case BPF_PROG_TYPE_TRACING:
+		if (attr->link_create.attach_type != prog->expected_attach_type) {
+			ret = -EINVAL;
+			goto out;
+		}
+		if (prog->expected_attach_type == BPF_TRACE_RAW_TP)
+			ret = bpf_raw_tp_link_attach(prog, NULL);
+		else if (prog->expected_attach_type == BPF_TRACE_ITER)
+			ret = bpf_iter_link_attach(attr, uattr, prog);
+		else if (prog->expected_attach_type == BPF_LSM_CGROUP)
+			ret = cgroup_bpf_link_attach(attr, prog);
+		else
+			ret = bpf_tracing_prog_attach(prog,
+						      attr->link_create.target_fd,
+						      attr->link_create.target_btf_id,
+						      attr->link_create.tracing.cookie);
+		break;
+	case BPF_PROG_TYPE_FLOW_DISSECTOR:
+	case BPF_PROG_TYPE_SK_LOOKUP:
+		ret = netns_bpf_link_create(attr, prog);
+		break;
+#ifdef CONFIG_NET
+	case BPF_PROG_TYPE_XDP:
+		ret = bpf_xdp_link_attach(attr, prog);
+		break;
+#endif
+	case BPF_PROG_TYPE_PERF_EVENT:
+	case BPF_PROG_TYPE_TRACEPOINT:
+		ret = bpf_perf_link_attach(attr, prog);
+		break;
+	case BPF_PROG_TYPE_KPROBE:
+		if (attr->link_create.attach_type == BPF_PERF_EVENT)
+			ret = bpf_perf_link_attach(attr, prog);
+		else
+			ret = bpf_kprobe_multi_link_attach(attr, prog);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+out:
+	if (ret < 0)
+		bpf_prog_put(prog);
+	return ret;
+}
+
+#define BPF_LINK_UPDATE_LAST_FIELD link_update.old_prog_fd
+
+static int link_update(union bpf_attr *attr)
+{
+	struct bpf_prog *old_prog = NULL, *new_prog;
+	struct bpf_link *link;
+	u32 flags;
+	int ret;
+
+	if (CHECK_ATTR(BPF_LINK_UPDATE))
+		return -EINVAL;
+
+	flags = attr->link_update.flags;
+	if (flags & ~BPF_F_REPLACE)
+		return -EINVAL;
+
+	link = bpf_link_get_from_fd(attr->link_update.link_fd);
+	if (IS_ERR(link))
+		return PTR_ERR(link);
+
+	new_prog = bpf_prog_get(attr->link_update.new_prog_fd);
+	if (IS_ERR(new_prog)) {
+		ret = PTR_ERR(new_prog);
+		goto out_put_link;
+	}
+
+	if (flags & BPF_F_REPLACE) {
+		old_prog = bpf_prog_get(attr->link_update.old_prog_fd);
+		if (IS_ERR(old_prog)) {
+			ret = PTR_ERR(old_prog);
+			old_prog = NULL;
+			goto out_put_progs;
+		}
+	} else if (attr->link_update.old_prog_fd) {
+		ret = -EINVAL;
+		goto out_put_progs;
+	}
+
+	if (link->ops->update_prog)
+		ret = link->ops->update_prog(link, new_prog, old_prog);
+	else
+		ret = -EINVAL;
+
+out_put_progs:
+	if (old_prog)
+		bpf_prog_put(old_prog);
+	if (ret)
+		bpf_prog_put(new_prog);
+out_put_link:
+	bpf_link_put(link);
+	return ret;
+}
+
+#define BPF_LINK_DETACH_LAST_FIELD link_detach.link_fd
+
+static int link_detach(union bpf_attr *attr)
+{
+	struct bpf_link *link;
+	int ret;
+
+	if (CHECK_ATTR(BPF_LINK_DETACH))
+		return -EINVAL;
+
+	link = bpf_link_get_from_fd(attr->link_detach.link_fd);
+	if (IS_ERR(link))
+		return PTR_ERR(link);
+
+	if (link->ops->detach)
+		ret = link->ops->detach(link);
+	else
+		ret = -EOPNOTSUPP;
+
+	bpf_link_put(link);
+	return ret;
+}
+
+static struct bpf_link *bpf_link_inc_not_zero(struct bpf_link *link)
+{
+	return atomic64_fetch_add_unless(&link->refcnt, 1, 0) ? link : ERR_PTR(-ENOENT);
+}
+
+struct bpf_link *bpf_link_by_id(u32 id)
+{
+	struct bpf_link *link;
+
+	if (!id)
+		return ERR_PTR(-ENOENT);
+
+	spin_lock_bh(&link_idr_lock);
+	/* before link is "settled", ID is 0, pretend it doesn't exist yet */
+	link = idr_find(&link_idr, id);
+	if (link) {
+		if (link->id)
+			link = bpf_link_inc_not_zero(link);
+		else
+			link = ERR_PTR(-EAGAIN);
+	} else {
+		link = ERR_PTR(-ENOENT);
+	}
+	spin_unlock_bh(&link_idr_lock);
+	return link;
+}
+
+struct bpf_link *bpf_link_get_curr_or_next(u32 *id)
+{
+	struct bpf_link *link;
+
+	spin_lock_bh(&link_idr_lock);
+again:
+	link = idr_get_next(&link_idr, id);
+	if (link) {
+		link = bpf_link_inc_not_zero(link);
+		if (IS_ERR(link)) {
+			(*id)++;
+			goto again;
+		}
+	}
+	spin_unlock_bh(&link_idr_lock);
+
+	return link;
+}
+
+#define BPF_LINK_GET_FD_BY_ID_LAST_FIELD link_id
+
+static int bpf_link_get_fd_by_id(const union bpf_attr *attr)
+{
+	struct bpf_link *link;
+	u32 id = attr->link_id;
+	int fd;
+
+	if (CHECK_ATTR(BPF_LINK_GET_FD_BY_ID))
+		return -EINVAL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	link = bpf_link_by_id(id);
+	if (IS_ERR(link))
+		return PTR_ERR(link);
+
+	fd = bpf_link_new_fd(link);
+	if (fd < 0)
+		bpf_link_put(link);
+
+	return fd;
+}
+
+DEFINE_MUTEX(bpf_stats_enabled_mutex);
+
+static int bpf_stats_release(struct inode *inode, struct file *file)
+{
+	mutex_lock(&bpf_stats_enabled_mutex);
+	static_key_slow_dec(&bpf_stats_enabled_key.key);
+	mutex_unlock(&bpf_stats_enabled_mutex);
+	return 0;
+}
+
+static const struct file_operations bpf_stats_fops = {
+	.release = bpf_stats_release,
+};
+
+static int bpf_enable_runtime_stats(void)
+{
+	int fd;
+
+	mutex_lock(&bpf_stats_enabled_mutex);
+
+	/* Set a very high limit to avoid overflow */
+	if (static_key_count(&bpf_stats_enabled_key.key) > INT_MAX / 2) {
+		mutex_unlock(&bpf_stats_enabled_mutex);
+		return -EBUSY;
+	}
+
+	fd = anon_inode_getfd("bpf-stats", &bpf_stats_fops, NULL, O_CLOEXEC);
+	if (fd >= 0)
+		static_key_slow_inc(&bpf_stats_enabled_key.key);
+
+	mutex_unlock(&bpf_stats_enabled_mutex);
+	return fd;
+}
+
+#define BPF_ENABLE_STATS_LAST_FIELD enable_stats.type
+
+static int bpf_enable_stats(union bpf_attr *attr)
+{
+
+	if (CHECK_ATTR(BPF_ENABLE_STATS))
+		return -EINVAL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	switch (attr->enable_stats.type) {
+	case BPF_STATS_RUN_TIME:
+		return bpf_enable_runtime_stats();
+	default:
+		break;
+	}
+	return -EINVAL;
+}
+
+#define BPF_ITER_CREATE_LAST_FIELD iter_create.flags
+
+static int bpf_iter_create(union bpf_attr *attr)
+{
+	struct bpf_link *link;
+	int err;
+
+	if (CHECK_ATTR(BPF_ITER_CREATE))
+		return -EINVAL;
+
+	if (attr->iter_create.flags)
+		return -EINVAL;
+
+	link = bpf_link_get_from_fd(attr->iter_create.link_fd);
+	if (IS_ERR(link))
+		return PTR_ERR(link);
+
+	err = bpf_iter_new_fd(link);
+	bpf_link_put(link);
+
+	return err;
+}
+
+#define BPF_PROG_BIND_MAP_LAST_FIELD prog_bind_map.flags
+
+static int bpf_prog_bind_map(union bpf_attr *attr)
+{
+	struct bpf_prog *prog;
+	struct bpf_map *map;
+	struct bpf_map **used_maps_old, **used_maps_new;
+	int i, ret = 0;
+
+	if (CHECK_ATTR(BPF_PROG_BIND_MAP))
+		return -EINVAL;
+
+	if (attr->prog_bind_map.flags)
+		return -EINVAL;
+
+	prog = bpf_prog_get(attr->prog_bind_map.prog_fd);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
+	map = bpf_map_get(attr->prog_bind_map.map_fd);
+	if (IS_ERR(map)) {
+		ret = PTR_ERR(map);
+		goto out_prog_put;
+	}
+
+	mutex_lock(&prog->aux->used_maps_mutex);
+
+	used_maps_old = prog->aux->used_maps;
+
+	for (i = 0; i < prog->aux->used_map_cnt; i++)
+		if (used_maps_old[i] == map) {
+			bpf_map_put(map);
+			goto out_unlock;
+		}
+
+	used_maps_new = kmalloc_array(prog->aux->used_map_cnt + 1,
+				      sizeof(used_maps_new[0]),
+				      GFP_KERNEL);
+	if (!used_maps_new) {
+		ret = -ENOMEM;
+		goto out_unlock;
+	}
+
+	memcpy(used_maps_new, used_maps_old,
+	       sizeof(used_maps_old[0]) * prog->aux->used_map_cnt);
+	used_maps_new[prog->aux->used_map_cnt] = map;
+
+	prog->aux->used_map_cnt++;
+	prog->aux->used_maps = used_maps_new;
+
+	kfree(used_maps_old);
+
+out_unlock:
+	mutex_unlock(&prog->aux->used_maps_mutex);
+
+	if (ret)
+		bpf_map_put(map);
+out_prog_put:
+	bpf_prog_put(prog);
+	return ret;
+}
+
+static int __sys_bpf(int cmd, bpfptr_t uattr, unsigned int size)
+{
+	union bpf_attr attr;
+	bool capable;
+	int err;
+
+	capable = bpf_capable() || !sysctl_unprivileged_bpf_disabled;
+
+	/* Intent here is for unprivileged_bpf_disabled to block key object
+	 * creation commands for unprivileged users; other actions depend
+	 * of fd availability and access to bpffs, so are dependent on
+	 * object creation success.  Capabilities are later verified for
+	 * operations such as load and map create, so even with unprivileged
+	 * BPF disabled, capability checks are still carried out for these
+	 * and other operations.
+	 */
+	if (!capable &&
+	    (cmd == BPF_MAP_CREATE || cmd == BPF_PROG_LOAD))
+		return -EPERM;
+
+	err = bpf_check_uarg_tail_zero(uattr, sizeof(attr), size);
+	if (err)
+		return err;
+	size = min_t(u32, size, sizeof(attr));
+
+	/* copy attributes from user space, may be less than sizeof(bpf_attr) */
+	memset(&attr, 0, sizeof(attr));
+	if (copy_from_bpfptr(&attr, uattr, size) != 0)
+		return -EFAULT;
+
+	err = security_bpf(cmd, &attr, size);
+	if (err < 0)
+		return err;
+
+	switch (cmd) {
+	case BPF_MAP_CREATE:
+		err = map_create(&attr);
+		break;
+	case BPF_MAP_LOOKUP_ELEM:
+		err = map_lookup_elem(&attr);
+		break;
+	case BPF_MAP_UPDATE_ELEM:
+		err = map_update_elem(&attr, uattr);
+		break;
+	case BPF_MAP_DELETE_ELEM:
+		err = map_delete_elem(&attr, uattr);
+		break;
+	case BPF_MAP_GET_NEXT_KEY:
+		err = map_get_next_key(&attr);
+		break;
+	case BPF_MAP_FREEZE:
+		err = map_freeze(&attr);
+		break;
+	case BPF_PROG_LOAD:
+		err = bpf_prog_load(&attr, uattr);
+		break;
+	case BPF_OBJ_PIN:
+		err = bpf_obj_pin(&attr);
+		break;
+	case BPF_OBJ_GET:
+		err = bpf_obj_get(&attr);
+		break;
+	case BPF_PROG_ATTACH:
+		err = bpf_prog_attach(&attr);
+		break;
+	case BPF_PROG_DETACH:
+		err = bpf_prog_detach(&attr);
+		break;
+	case BPF_PROG_QUERY:
+		err = bpf_prog_query(&attr, uattr.user);
+		break;
+	case BPF_PROG_TEST_RUN:
+		err = bpf_prog_test_run(&attr, uattr.user);
+		break;
+	case BPF_PROG_GET_NEXT_ID:
+		err = bpf_obj_get_next_id(&attr, uattr.user,
+					  &prog_idr, &prog_idr_lock);
+		break;
+	case BPF_MAP_GET_NEXT_ID:
+		err = bpf_obj_get_next_id(&attr, uattr.user,
+					  &map_idr, &map_idr_lock);
+		break;
+	case BPF_BTF_GET_NEXT_ID:
+		err = bpf_obj_get_next_id(&attr, uattr.user,
+					  &btf_idr, &btf_idr_lock);
+		break;
+	case BPF_PROG_GET_FD_BY_ID:
+		err = bpf_prog_get_fd_by_id(&attr);
+		break;
+	case BPF_MAP_GET_FD_BY_ID:
+		err = bpf_map_get_fd_by_id(&attr);
+		break;
+	case BPF_OBJ_GET_INFO_BY_FD:
+		err = bpf_obj_get_info_by_fd(&attr, uattr.user);
+		break;
+	case BPF_RAW_TRACEPOINT_OPEN:
+		err = bpf_raw_tracepoint_open(&attr);
+		break;
+	case BPF_BTF_LOAD:
+		err = bpf_btf_load(&attr, uattr);
+		break;
+	case BPF_BTF_GET_FD_BY_ID:
+		err = bpf_btf_get_fd_by_id(&attr);
+		break;
+	case BPF_TASK_FD_QUERY:
+		err = bpf_task_fd_query(&attr, uattr.user);
+		break;
+	case BPF_MAP_LOOKUP_AND_DELETE_ELEM:
+		err = map_lookup_and_delete_elem(&attr);
+		break;
+	case BPF_MAP_LOOKUP_BATCH:
+		err = bpf_map_do_batch(&attr, uattr.user, BPF_MAP_LOOKUP_BATCH);
+		break;
+	case BPF_MAP_LOOKUP_AND_DELETE_BATCH:
+		err = bpf_map_do_batch(&attr, uattr.user,
+				       BPF_MAP_LOOKUP_AND_DELETE_BATCH);
+		break;
+	case BPF_MAP_UPDATE_BATCH:
+		err = bpf_map_do_batch(&attr, uattr.user, BPF_MAP_UPDATE_BATCH);
+		break;
+	case BPF_MAP_DELETE_BATCH:
+		err = bpf_map_do_batch(&attr, uattr.user, BPF_MAP_DELETE_BATCH);
+		break;
+	case BPF_LINK_CREATE:
+		err = link_create(&attr, uattr);
+		break;
+	case BPF_LINK_UPDATE:
+		err = link_update(&attr);
+		break;
+	case BPF_LINK_GET_FD_BY_ID:
+		err = bpf_link_get_fd_by_id(&attr);
+		break;
+	case BPF_LINK_GET_NEXT_ID:
+		err = bpf_obj_get_next_id(&attr, uattr.user,
+					  &link_idr, &link_idr_lock);
+		break;
+	case BPF_ENABLE_STATS:
+		err = bpf_enable_stats(&attr);
+		break;
+	case BPF_ITER_CREATE:
+		err = bpf_iter_create(&attr);
+		break;
+	case BPF_LINK_DETACH:
+		err = link_detach(&attr);
+		break;
+	case BPF_PROG_BIND_MAP:
+		err = bpf_prog_bind_map(&attr);
+		break;
+	default:
+		err = -EINVAL;
+		break;
+	}
+
+	return err;
+}
+
+SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
+{
+	return __sys_bpf(cmd, USER_BPFPTR(uattr), size);
+}
+
+static bool syscall_prog_is_valid_access(int off, int size,
+					 enum bpf_access_type type,
+					 const struct bpf_prog *prog,
+					 struct bpf_insn_access_aux *info)
+{
+	if (off < 0 || off >= U16_MAX)
+		return false;
+	if (off % size != 0)
+		return false;
+	return true;
+}
+
+BPF_CALL_3(bpf_sys_bpf, int, cmd, union bpf_attr *, attr, u32, attr_size)
+{
+	switch (cmd) {
+	case BPF_MAP_CREATE:
+	case BPF_MAP_DELETE_ELEM:
+	case BPF_MAP_UPDATE_ELEM:
+	case BPF_MAP_FREEZE:
+	case BPF_MAP_GET_FD_BY_ID:
+	case BPF_PROG_LOAD:
+	case BPF_BTF_LOAD:
+	case BPF_LINK_CREATE:
+	case BPF_RAW_TRACEPOINT_OPEN:
+		break;
+	default:
+		return -EINVAL;
+	}
+	return __sys_bpf(cmd, KERNEL_BPFPTR(attr), attr_size);
+}
+
+
+/* To shut up -Wmissing-prototypes.
+ * This function is used by the kernel light skeleton
+ * to load bpf programs when modules are loaded or during kernel boot.
+ * See tools/lib/bpf/skel_internal.h
+ */
+int kern_sys_bpf(int cmd, union bpf_attr *attr, unsigned int size);
+
+int kern_sys_bpf(int cmd, union bpf_attr *attr, unsigned int size)
+{
+	struct bpf_prog * __maybe_unused prog;
+	struct bpf_tramp_run_ctx __maybe_unused run_ctx;
+
+	switch (cmd) {
+#ifdef CONFIG_BPF_JIT /* __bpf_prog_enter_sleepable used by trampoline and JIT */
+	case BPF_PROG_TEST_RUN:
+		if (attr->test.data_in || attr->test.data_out ||
+		    attr->test.ctx_out || attr->test.duration ||
+		    attr->test.repeat || attr->test.flags)
+			return -EINVAL;
+
+		prog = bpf_prog_get_type(attr->test.prog_fd, BPF_PROG_TYPE_SYSCALL);
+		if (IS_ERR(prog))
+			return PTR_ERR(prog);
+
+		if (attr->test.ctx_size_in < prog->aux->max_ctx_offset ||
+		    attr->test.ctx_size_in > U16_MAX) {
+			bpf_prog_put(prog);
+			return -EINVAL;
+		}
+
+		run_ctx.bpf_cookie = 0;
+		if (!__bpf_prog_enter_sleepable_recur(prog, &run_ctx)) {
+			/* recursion detected */
+			__bpf_prog_exit_sleepable_recur(prog, 0, &run_ctx);
+			bpf_prog_put(prog);
+			return -EBUSY;
+		}
+		attr->test.retval = bpf_prog_run(prog, (void *) (long) attr->test.ctx_in);
+		__bpf_prog_exit_sleepable_recur(prog, 0 /* bpf_prog_run does runtime stats */,
+						&run_ctx);
+		bpf_prog_put(prog);
+		return 0;
+#endif
+	default:
+		return ____bpf_sys_bpf(cmd, attr, size);
+	}
+}
+EXPORT_SYMBOL(kern_sys_bpf);
+
+static const struct bpf_func_proto bpf_sys_bpf_proto = {
+	.func		= bpf_sys_bpf,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_ANYTHING,
+	.arg2_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg3_type	= ARG_CONST_SIZE,
+};
+
+const struct bpf_func_proto * __weak
+tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	return bpf_base_func_proto(func_id);
+}
+
+BPF_CALL_1(bpf_sys_close, u32, fd)
+{
+	/* When bpf program calls this helper there should not be
+	 * an fdget() without matching completed fdput().
+	 * This helper is allowed in the following callchain only:
+	 * sys_bpf->prog_test_run->bpf_prog->bpf_sys_close
+	 */
+	return close_fd(fd);
+}
+
+static const struct bpf_func_proto bpf_sys_close_proto = {
+	.func		= bpf_sys_close,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_4(bpf_kallsyms_lookup_name, const char *, name, int, name_sz, int, flags, u64 *, res)
+{
+	if (flags)
+		return -EINVAL;
+
+	if (name_sz <= 1 || name[name_sz - 1])
+		return -EINVAL;
+
+	if (!bpf_dump_raw_ok(current_cred()))
+		return -EPERM;
+
+	*res = kallsyms_lookup_name(name);
+	return *res ? 0 : -ENOENT;
+}
+
+static const struct bpf_func_proto bpf_kallsyms_lookup_name_proto = {
+	.func		= bpf_kallsyms_lookup_name,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_MEM,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_PTR_TO_LONG,
+};
+
+static const struct bpf_func_proto *
+syscall_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	switch (func_id) {
+	case BPF_FUNC_sys_bpf:
+		return !perfmon_capable() ? NULL : &bpf_sys_bpf_proto;
+	case BPF_FUNC_btf_find_by_name_kind:
+		return &bpf_btf_find_by_name_kind_proto;
+	case BPF_FUNC_sys_close:
+		return &bpf_sys_close_proto;
+	case BPF_FUNC_kallsyms_lookup_name:
+		return &bpf_kallsyms_lookup_name_proto;
+	default:
+		return tracing_prog_func_proto(func_id, prog);
+	}
+}
+
+const struct bpf_verifier_ops bpf_syscall_verifier_ops = {
+	.get_func_proto  = syscall_prog_func_proto,
+	.is_valid_access = syscall_prog_is_valid_access,
+};
+
+const struct bpf_prog_ops bpf_syscall_prog_ops = {
+	.test_run = bpf_prog_test_run_syscall,
+};
+
+#ifdef CONFIG_SYSCTL
+static int bpf_stats_handler(struct ctl_table *table, int write,
+			     void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct static_key *key = (struct static_key *)table->data;
+	static int saved_val;
+	int val, ret;
+	struct ctl_table tmp = {
+		.data   = &val,
+		.maxlen = sizeof(val),
+		.mode   = table->mode,
+		.extra1 = SYSCTL_ZERO,
+		.extra2 = SYSCTL_ONE,
+	};
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	mutex_lock(&bpf_stats_enabled_mutex);
+	val = saved_val;
+	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+	if (write && !ret && val != saved_val) {
+		if (val)
+			static_key_slow_inc(key);
+		else
+			static_key_slow_dec(key);
+		saved_val = val;
+	}
+	mutex_unlock(&bpf_stats_enabled_mutex);
+	return ret;
+}
+
+void __weak unpriv_ebpf_notify(int new_state)
+{
+}
+
+static int bpf_unpriv_handler(struct ctl_table *table, int write,
+			      void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int ret, unpriv_enable = *(int *)table->data;
+	bool locked_state = unpriv_enable == 1;
+	struct ctl_table tmp = *table;
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	tmp.data = &unpriv_enable;
+	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+	if (write && !ret) {
+		if (locked_state && unpriv_enable != 1)
+			return -EPERM;
+		*(int *)table->data = unpriv_enable;
+	}
+
+	if (write)
+		unpriv_ebpf_notify(unpriv_enable);
+
+	return ret;
+}
+
+static struct ctl_table bpf_syscall_table[] = {
+	{
+		.procname	= "unprivileged_bpf_disabled",
+		.data		= &sysctl_unprivileged_bpf_disabled,
+		.maxlen		= sizeof(sysctl_unprivileged_bpf_disabled),
+		.mode		= 0644,
+		.proc_handler	= bpf_unpriv_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_TWO,
+	},
+	{
+		.procname	= "bpf_stats_enabled",
+		.data		= &bpf_stats_enabled_key.key,
+		.maxlen		= sizeof(bpf_stats_enabled_key),
+		.mode		= 0644,
+		.proc_handler	= bpf_stats_handler,
+	},
+	{ }
+};
+
+static int __init bpf_syscall_sysctl_init(void)
+{
+	register_sysctl_init("kernel", bpf_syscall_table);
+	return 0;
+}
+late_initcall(bpf_syscall_sysctl_init);
+#endif /* CONFIG_SYSCTL */
diff --git a/kernel/bpf/sysfs_btf.c b/kernel/bpf/sysfs_btf.c
new file mode 100644
index 000000000..ef6911aee
--- /dev/null
+++ b/kernel/bpf/sysfs_btf.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Provide kernel BTF information for introspection and use by eBPF tools.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kobject.h>
+#include <linux/init.h>
+#include <linux/sysfs.h>
+
+/* See scripts/link-vmlinux.sh, gen_btf() func for details */
+extern char __weak __start_BTF[];
+extern char __weak __stop_BTF[];
+
+static ssize_t
+btf_vmlinux_read(struct file *file, struct kobject *kobj,
+		 struct bin_attribute *bin_attr,
+		 char *buf, loff_t off, size_t len)
+{
+	memcpy(buf, __start_BTF + off, len);
+	return len;
+}
+
+static struct bin_attribute bin_attr_btf_vmlinux __ro_after_init = {
+	.attr = { .name = "vmlinux", .mode = 0444, },
+	.read = btf_vmlinux_read,
+};
+
+struct kobject *btf_kobj;
+
+static int __init btf_vmlinux_init(void)
+{
+	bin_attr_btf_vmlinux.size = __stop_BTF - __start_BTF;
+
+	if (!__start_BTF || bin_attr_btf_vmlinux.size == 0)
+		return 0;
+
+	btf_kobj = kobject_create_and_add("btf", kernel_kobj);
+	if (!btf_kobj)
+		return -ENOMEM;
+
+	return sysfs_create_bin_file(btf_kobj, &bin_attr_btf_vmlinux);
+}
+
+subsys_initcall(btf_vmlinux_init);
diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
new file mode 100644
index 000000000..c4ab9d6cd
--- /dev/null
+++ b/kernel/bpf/task_iter.c
@@ -0,0 +1,864 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2020 Facebook */
+
+#include <linux/init.h>
+#include <linux/namei.h>
+#include <linux/pid_namespace.h>
+#include <linux/fs.h>
+#include <linux/fdtable.h>
+#include <linux/filter.h>
+#include <linux/btf_ids.h>
+#include "mmap_unlock_work.h"
+
+static const char * const iter_task_type_names[] = {
+	"ALL",
+	"TID",
+	"PID",
+};
+
+struct bpf_iter_seq_task_common {
+	struct pid_namespace *ns;
+	enum bpf_iter_task_type	type;
+	u32 pid;
+	u32 pid_visiting;
+};
+
+struct bpf_iter_seq_task_info {
+	/* The first field must be struct bpf_iter_seq_task_common.
+	 * this is assumed by {init, fini}_seq_pidns() callback functions.
+	 */
+	struct bpf_iter_seq_task_common common;
+	u32 tid;
+};
+
+static struct task_struct *task_group_seq_get_next(struct bpf_iter_seq_task_common *common,
+						   u32 *tid,
+						   bool skip_if_dup_files)
+{
+	struct task_struct *task, *next_task;
+	struct pid *pid;
+	u32 saved_tid;
+
+	if (!*tid) {
+		/* The first time, the iterator calls this function. */
+		pid = find_pid_ns(common->pid, common->ns);
+		if (!pid)
+			return NULL;
+
+		task = get_pid_task(pid, PIDTYPE_TGID);
+		if (!task)
+			return NULL;
+
+		*tid = common->pid;
+		common->pid_visiting = common->pid;
+
+		return task;
+	}
+
+	/* If the control returns to user space and comes back to the
+	 * kernel again, *tid and common->pid_visiting should be the
+	 * same for task_seq_start() to pick up the correct task.
+	 */
+	if (*tid == common->pid_visiting) {
+		pid = find_pid_ns(common->pid_visiting, common->ns);
+		task = get_pid_task(pid, PIDTYPE_PID);
+
+		return task;
+	}
+
+	pid = find_pid_ns(common->pid_visiting, common->ns);
+	if (!pid)
+		return NULL;
+
+	task = get_pid_task(pid, PIDTYPE_PID);
+	if (!task)
+		return NULL;
+
+retry:
+	if (!pid_alive(task)) {
+		put_task_struct(task);
+		return NULL;
+	}
+
+	next_task = next_thread(task);
+	put_task_struct(task);
+	if (!next_task)
+		return NULL;
+
+	saved_tid = *tid;
+	*tid = __task_pid_nr_ns(next_task, PIDTYPE_PID, common->ns);
+	if (!*tid || *tid == common->pid) {
+		/* Run out of tasks of a process.  The tasks of a
+		 * thread_group are linked as circular linked list.
+		 */
+		*tid = saved_tid;
+		return NULL;
+	}
+
+	get_task_struct(next_task);
+	common->pid_visiting = *tid;
+
+	if (skip_if_dup_files && task->files == task->group_leader->files) {
+		task = next_task;
+		goto retry;
+	}
+
+	return next_task;
+}
+
+static struct task_struct *task_seq_get_next(struct bpf_iter_seq_task_common *common,
+					     u32 *tid,
+					     bool skip_if_dup_files)
+{
+	struct task_struct *task = NULL;
+	struct pid *pid;
+
+	if (common->type == BPF_TASK_ITER_TID) {
+		if (*tid && *tid != common->pid)
+			return NULL;
+		rcu_read_lock();
+		pid = find_pid_ns(common->pid, common->ns);
+		if (pid) {
+			task = get_pid_task(pid, PIDTYPE_TGID);
+			*tid = common->pid;
+		}
+		rcu_read_unlock();
+
+		return task;
+	}
+
+	if (common->type == BPF_TASK_ITER_TGID) {
+		rcu_read_lock();
+		task = task_group_seq_get_next(common, tid, skip_if_dup_files);
+		rcu_read_unlock();
+
+		return task;
+	}
+
+	rcu_read_lock();
+retry:
+	pid = find_ge_pid(*tid, common->ns);
+	if (pid) {
+		*tid = pid_nr_ns(pid, common->ns);
+		task = get_pid_task(pid, PIDTYPE_PID);
+		if (!task) {
+			++*tid;
+			goto retry;
+		} else if (skip_if_dup_files && !thread_group_leader(task) &&
+			   task->files == task->group_leader->files) {
+			put_task_struct(task);
+			task = NULL;
+			++*tid;
+			goto retry;
+		}
+	}
+	rcu_read_unlock();
+
+	return task;
+}
+
+static void *task_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct bpf_iter_seq_task_info *info = seq->private;
+	struct task_struct *task;
+
+	task = task_seq_get_next(&info->common, &info->tid, false);
+	if (!task)
+		return NULL;
+
+	if (*pos == 0)
+		++*pos;
+	return task;
+}
+
+static void *task_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct bpf_iter_seq_task_info *info = seq->private;
+	struct task_struct *task;
+
+	++*pos;
+	++info->tid;
+	put_task_struct((struct task_struct *)v);
+	task = task_seq_get_next(&info->common, &info->tid, false);
+	if (!task)
+		return NULL;
+
+	return task;
+}
+
+struct bpf_iter__task {
+	__bpf_md_ptr(struct bpf_iter_meta *, meta);
+	__bpf_md_ptr(struct task_struct *, task);
+};
+
+DEFINE_BPF_ITER_FUNC(task, struct bpf_iter_meta *meta, struct task_struct *task)
+
+static int __task_seq_show(struct seq_file *seq, struct task_struct *task,
+			   bool in_stop)
+{
+	struct bpf_iter_meta meta;
+	struct bpf_iter__task ctx;
+	struct bpf_prog *prog;
+
+	meta.seq = seq;
+	prog = bpf_iter_get_info(&meta, in_stop);
+	if (!prog)
+		return 0;
+
+	ctx.meta = &meta;
+	ctx.task = task;
+	return bpf_iter_run_prog(prog, &ctx);
+}
+
+static int task_seq_show(struct seq_file *seq, void *v)
+{
+	return __task_seq_show(seq, v, false);
+}
+
+static void task_seq_stop(struct seq_file *seq, void *v)
+{
+	if (!v)
+		(void)__task_seq_show(seq, v, true);
+	else
+		put_task_struct((struct task_struct *)v);
+}
+
+static int bpf_iter_attach_task(struct bpf_prog *prog,
+				union bpf_iter_link_info *linfo,
+				struct bpf_iter_aux_info *aux)
+{
+	unsigned int flags;
+	struct pid *pid;
+	pid_t tgid;
+
+	if ((!!linfo->task.tid + !!linfo->task.pid + !!linfo->task.pid_fd) > 1)
+		return -EINVAL;
+
+	aux->task.type = BPF_TASK_ITER_ALL;
+	if (linfo->task.tid != 0) {
+		aux->task.type = BPF_TASK_ITER_TID;
+		aux->task.pid = linfo->task.tid;
+	}
+	if (linfo->task.pid != 0) {
+		aux->task.type = BPF_TASK_ITER_TGID;
+		aux->task.pid = linfo->task.pid;
+	}
+	if (linfo->task.pid_fd != 0) {
+		aux->task.type = BPF_TASK_ITER_TGID;
+
+		pid = pidfd_get_pid(linfo->task.pid_fd, &flags);
+		if (IS_ERR(pid))
+			return PTR_ERR(pid);
+
+		tgid = pid_nr_ns(pid, task_active_pid_ns(current));
+		aux->task.pid = tgid;
+		put_pid(pid);
+	}
+
+	return 0;
+}
+
+static const struct seq_operations task_seq_ops = {
+	.start	= task_seq_start,
+	.next	= task_seq_next,
+	.stop	= task_seq_stop,
+	.show	= task_seq_show,
+};
+
+struct bpf_iter_seq_task_file_info {
+	/* The first field must be struct bpf_iter_seq_task_common.
+	 * this is assumed by {init, fini}_seq_pidns() callback functions.
+	 */
+	struct bpf_iter_seq_task_common common;
+	struct task_struct *task;
+	u32 tid;
+	u32 fd;
+};
+
+static struct file *
+task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info)
+{
+	u32 saved_tid = info->tid;
+	struct task_struct *curr_task;
+	unsigned int curr_fd = info->fd;
+
+	/* If this function returns a non-NULL file object,
+	 * it held a reference to the task/file.
+	 * Otherwise, it does not hold any reference.
+	 */
+again:
+	if (info->task) {
+		curr_task = info->task;
+		curr_fd = info->fd;
+	} else {
+		curr_task = task_seq_get_next(&info->common, &info->tid, true);
+                if (!curr_task) {
+                        info->task = NULL;
+                        return NULL;
+                }
+
+		/* set info->task */
+		info->task = curr_task;
+		if (saved_tid == info->tid)
+			curr_fd = info->fd;
+		else
+			curr_fd = 0;
+	}
+
+	rcu_read_lock();
+	for (;; curr_fd++) {
+		struct file *f;
+		f = task_lookup_next_fd_rcu(curr_task, &curr_fd);
+		if (!f)
+			break;
+		if (!get_file_rcu(f))
+			continue;
+
+		/* set info->fd */
+		info->fd = curr_fd;
+		rcu_read_unlock();
+		return f;
+	}
+
+	/* the current task is done, go to the next task */
+	rcu_read_unlock();
+	put_task_struct(curr_task);
+
+	if (info->common.type == BPF_TASK_ITER_TID) {
+		info->task = NULL;
+		return NULL;
+	}
+
+	info->task = NULL;
+	info->fd = 0;
+	saved_tid = ++(info->tid);
+	goto again;
+}
+
+static void *task_file_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct bpf_iter_seq_task_file_info *info = seq->private;
+	struct file *file;
+
+	info->task = NULL;
+	file = task_file_seq_get_next(info);
+	if (file && *pos == 0)
+		++*pos;
+
+	return file;
+}
+
+static void *task_file_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct bpf_iter_seq_task_file_info *info = seq->private;
+
+	++*pos;
+	++info->fd;
+	fput((struct file *)v);
+	return task_file_seq_get_next(info);
+}
+
+struct bpf_iter__task_file {
+	__bpf_md_ptr(struct bpf_iter_meta *, meta);
+	__bpf_md_ptr(struct task_struct *, task);
+	u32 fd __aligned(8);
+	__bpf_md_ptr(struct file *, file);
+};
+
+DEFINE_BPF_ITER_FUNC(task_file, struct bpf_iter_meta *meta,
+		     struct task_struct *task, u32 fd,
+		     struct file *file)
+
+static int __task_file_seq_show(struct seq_file *seq, struct file *file,
+				bool in_stop)
+{
+	struct bpf_iter_seq_task_file_info *info = seq->private;
+	struct bpf_iter__task_file ctx;
+	struct bpf_iter_meta meta;
+	struct bpf_prog *prog;
+
+	meta.seq = seq;
+	prog = bpf_iter_get_info(&meta, in_stop);
+	if (!prog)
+		return 0;
+
+	ctx.meta = &meta;
+	ctx.task = info->task;
+	ctx.fd = info->fd;
+	ctx.file = file;
+	return bpf_iter_run_prog(prog, &ctx);
+}
+
+static int task_file_seq_show(struct seq_file *seq, void *v)
+{
+	return __task_file_seq_show(seq, v, false);
+}
+
+static void task_file_seq_stop(struct seq_file *seq, void *v)
+{
+	struct bpf_iter_seq_task_file_info *info = seq->private;
+
+	if (!v) {
+		(void)__task_file_seq_show(seq, v, true);
+	} else {
+		fput((struct file *)v);
+		put_task_struct(info->task);
+		info->task = NULL;
+	}
+}
+
+static int init_seq_pidns(void *priv_data, struct bpf_iter_aux_info *aux)
+{
+	struct bpf_iter_seq_task_common *common = priv_data;
+
+	common->ns = get_pid_ns(task_active_pid_ns(current));
+	common->type = aux->task.type;
+	common->pid = aux->task.pid;
+
+	return 0;
+}
+
+static void fini_seq_pidns(void *priv_data)
+{
+	struct bpf_iter_seq_task_common *common = priv_data;
+
+	put_pid_ns(common->ns);
+}
+
+static const struct seq_operations task_file_seq_ops = {
+	.start	= task_file_seq_start,
+	.next	= task_file_seq_next,
+	.stop	= task_file_seq_stop,
+	.show	= task_file_seq_show,
+};
+
+struct bpf_iter_seq_task_vma_info {
+	/* The first field must be struct bpf_iter_seq_task_common.
+	 * this is assumed by {init, fini}_seq_pidns() callback functions.
+	 */
+	struct bpf_iter_seq_task_common common;
+	struct task_struct *task;
+	struct mm_struct *mm;
+	struct vm_area_struct *vma;
+	u32 tid;
+	unsigned long prev_vm_start;
+	unsigned long prev_vm_end;
+};
+
+enum bpf_task_vma_iter_find_op {
+	task_vma_iter_first_vma,   /* use find_vma() with addr 0 */
+	task_vma_iter_next_vma,    /* use vma_next() with curr_vma */
+	task_vma_iter_find_vma,    /* use find_vma() to find next vma */
+};
+
+static struct vm_area_struct *
+task_vma_seq_get_next(struct bpf_iter_seq_task_vma_info *info)
+{
+	enum bpf_task_vma_iter_find_op op;
+	struct vm_area_struct *curr_vma;
+	struct task_struct *curr_task;
+	struct mm_struct *curr_mm;
+	u32 saved_tid = info->tid;
+
+	/* If this function returns a non-NULL vma, it holds a reference to
+	 * the task_struct, holds a refcount on mm->mm_users, and holds
+	 * read lock on vma->mm->mmap_lock.
+	 * If this function returns NULL, it does not hold any reference or
+	 * lock.
+	 */
+	if (info->task) {
+		curr_task = info->task;
+		curr_vma = info->vma;
+		curr_mm = info->mm;
+		/* In case of lock contention, drop mmap_lock to unblock
+		 * the writer.
+		 *
+		 * After relock, call find(mm, prev_vm_end - 1) to find
+		 * new vma to process.
+		 *
+		 *   +------+------+-----------+
+		 *   | VMA1 | VMA2 | VMA3      |
+		 *   +------+------+-----------+
+		 *   |      |      |           |
+		 *  4k     8k     16k         400k
+		 *
+		 * For example, curr_vma == VMA2. Before unlock, we set
+		 *
+		 *    prev_vm_start = 8k
+		 *    prev_vm_end   = 16k
+		 *
+		 * There are a few cases:
+		 *
+		 * 1) VMA2 is freed, but VMA3 exists.
+		 *
+		 *    find_vma() will return VMA3, just process VMA3.
+		 *
+		 * 2) VMA2 still exists.
+		 *
+		 *    find_vma() will return VMA2, process VMA2->next.
+		 *
+		 * 3) no more vma in this mm.
+		 *
+		 *    Process the next task.
+		 *
+		 * 4) find_vma() returns a different vma, VMA2'.
+		 *
+		 *    4.1) If VMA2 covers same range as VMA2', skip VMA2',
+		 *         because we already covered the range;
+		 *    4.2) VMA2 and VMA2' covers different ranges, process
+		 *         VMA2'.
+		 */
+		if (mmap_lock_is_contended(curr_mm)) {
+			info->prev_vm_start = curr_vma->vm_start;
+			info->prev_vm_end = curr_vma->vm_end;
+			op = task_vma_iter_find_vma;
+			mmap_read_unlock(curr_mm);
+			if (mmap_read_lock_killable(curr_mm)) {
+				mmput(curr_mm);
+				goto finish;
+			}
+		} else {
+			op = task_vma_iter_next_vma;
+		}
+	} else {
+again:
+		curr_task = task_seq_get_next(&info->common, &info->tid, true);
+		if (!curr_task) {
+			info->tid++;
+			goto finish;
+		}
+
+		if (saved_tid != info->tid) {
+			/* new task, process the first vma */
+			op = task_vma_iter_first_vma;
+		} else {
+			/* Found the same tid, which means the user space
+			 * finished data in previous buffer and read more.
+			 * We dropped mmap_lock before returning to user
+			 * space, so it is necessary to use find_vma() to
+			 * find the next vma to process.
+			 */
+			op = task_vma_iter_find_vma;
+		}
+
+		curr_mm = get_task_mm(curr_task);
+		if (!curr_mm)
+			goto next_task;
+
+		if (mmap_read_lock_killable(curr_mm)) {
+			mmput(curr_mm);
+			goto finish;
+		}
+	}
+
+	switch (op) {
+	case task_vma_iter_first_vma:
+		curr_vma = find_vma(curr_mm, 0);
+		break;
+	case task_vma_iter_next_vma:
+		curr_vma = find_vma(curr_mm, curr_vma->vm_end);
+		break;
+	case task_vma_iter_find_vma:
+		/* We dropped mmap_lock so it is necessary to use find_vma
+		 * to find the next vma. This is similar to the  mechanism
+		 * in show_smaps_rollup().
+		 */
+		curr_vma = find_vma(curr_mm, info->prev_vm_end - 1);
+		/* case 1) and 4.2) above just use curr_vma */
+
+		/* check for case 2) or case 4.1) above */
+		if (curr_vma &&
+		    curr_vma->vm_start == info->prev_vm_start &&
+		    curr_vma->vm_end == info->prev_vm_end)
+			curr_vma = find_vma(curr_mm, curr_vma->vm_end);
+		break;
+	}
+	if (!curr_vma) {
+		/* case 3) above, or case 2) 4.1) with vma->next == NULL */
+		mmap_read_unlock(curr_mm);
+		mmput(curr_mm);
+		goto next_task;
+	}
+	info->task = curr_task;
+	info->vma = curr_vma;
+	info->mm = curr_mm;
+	return curr_vma;
+
+next_task:
+	if (info->common.type == BPF_TASK_ITER_TID)
+		goto finish;
+
+	put_task_struct(curr_task);
+	info->task = NULL;
+	info->mm = NULL;
+	info->tid++;
+	goto again;
+
+finish:
+	if (curr_task)
+		put_task_struct(curr_task);
+	info->task = NULL;
+	info->vma = NULL;
+	info->mm = NULL;
+	return NULL;
+}
+
+static void *task_vma_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct bpf_iter_seq_task_vma_info *info = seq->private;
+	struct vm_area_struct *vma;
+
+	vma = task_vma_seq_get_next(info);
+	if (vma && *pos == 0)
+		++*pos;
+
+	return vma;
+}
+
+static void *task_vma_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct bpf_iter_seq_task_vma_info *info = seq->private;
+
+	++*pos;
+	return task_vma_seq_get_next(info);
+}
+
+struct bpf_iter__task_vma {
+	__bpf_md_ptr(struct bpf_iter_meta *, meta);
+	__bpf_md_ptr(struct task_struct *, task);
+	__bpf_md_ptr(struct vm_area_struct *, vma);
+};
+
+DEFINE_BPF_ITER_FUNC(task_vma, struct bpf_iter_meta *meta,
+		     struct task_struct *task, struct vm_area_struct *vma)
+
+static int __task_vma_seq_show(struct seq_file *seq, bool in_stop)
+{
+	struct bpf_iter_seq_task_vma_info *info = seq->private;
+	struct bpf_iter__task_vma ctx;
+	struct bpf_iter_meta meta;
+	struct bpf_prog *prog;
+
+	meta.seq = seq;
+	prog = bpf_iter_get_info(&meta, in_stop);
+	if (!prog)
+		return 0;
+
+	ctx.meta = &meta;
+	ctx.task = info->task;
+	ctx.vma = info->vma;
+	return bpf_iter_run_prog(prog, &ctx);
+}
+
+static int task_vma_seq_show(struct seq_file *seq, void *v)
+{
+	return __task_vma_seq_show(seq, false);
+}
+
+static void task_vma_seq_stop(struct seq_file *seq, void *v)
+{
+	struct bpf_iter_seq_task_vma_info *info = seq->private;
+
+	if (!v) {
+		(void)__task_vma_seq_show(seq, true);
+	} else {
+		/* info->vma has not been seen by the BPF program. If the
+		 * user space reads more, task_vma_seq_get_next should
+		 * return this vma again. Set prev_vm_start to ~0UL,
+		 * so that we don't skip the vma returned by the next
+		 * find_vma() (case task_vma_iter_find_vma in
+		 * task_vma_seq_get_next()).
+		 */
+		info->prev_vm_start = ~0UL;
+		info->prev_vm_end = info->vma->vm_end;
+		mmap_read_unlock(info->mm);
+		mmput(info->mm);
+		info->mm = NULL;
+		put_task_struct(info->task);
+		info->task = NULL;
+	}
+}
+
+static const struct seq_operations task_vma_seq_ops = {
+	.start	= task_vma_seq_start,
+	.next	= task_vma_seq_next,
+	.stop	= task_vma_seq_stop,
+	.show	= task_vma_seq_show,
+};
+
+static const struct bpf_iter_seq_info task_seq_info = {
+	.seq_ops		= &task_seq_ops,
+	.init_seq_private	= init_seq_pidns,
+	.fini_seq_private	= fini_seq_pidns,
+	.seq_priv_size		= sizeof(struct bpf_iter_seq_task_info),
+};
+
+static int bpf_iter_fill_link_info(const struct bpf_iter_aux_info *aux, struct bpf_link_info *info)
+{
+	switch (aux->task.type) {
+	case BPF_TASK_ITER_TID:
+		info->iter.task.tid = aux->task.pid;
+		break;
+	case BPF_TASK_ITER_TGID:
+		info->iter.task.pid = aux->task.pid;
+		break;
+	default:
+		break;
+	}
+	return 0;
+}
+
+static void bpf_iter_task_show_fdinfo(const struct bpf_iter_aux_info *aux, struct seq_file *seq)
+{
+	seq_printf(seq, "task_type:\t%s\n", iter_task_type_names[aux->task.type]);
+	if (aux->task.type == BPF_TASK_ITER_TID)
+		seq_printf(seq, "tid:\t%u\n", aux->task.pid);
+	else if (aux->task.type == BPF_TASK_ITER_TGID)
+		seq_printf(seq, "pid:\t%u\n", aux->task.pid);
+}
+
+static struct bpf_iter_reg task_reg_info = {
+	.target			= "task",
+	.attach_target		= bpf_iter_attach_task,
+	.feature		= BPF_ITER_RESCHED,
+	.ctx_arg_info_size	= 1,
+	.ctx_arg_info		= {
+		{ offsetof(struct bpf_iter__task, task),
+		  PTR_TO_BTF_ID_OR_NULL },
+	},
+	.seq_info		= &task_seq_info,
+	.fill_link_info		= bpf_iter_fill_link_info,
+	.show_fdinfo		= bpf_iter_task_show_fdinfo,
+};
+
+static const struct bpf_iter_seq_info task_file_seq_info = {
+	.seq_ops		= &task_file_seq_ops,
+	.init_seq_private	= init_seq_pidns,
+	.fini_seq_private	= fini_seq_pidns,
+	.seq_priv_size		= sizeof(struct bpf_iter_seq_task_file_info),
+};
+
+static struct bpf_iter_reg task_file_reg_info = {
+	.target			= "task_file",
+	.attach_target		= bpf_iter_attach_task,
+	.feature		= BPF_ITER_RESCHED,
+	.ctx_arg_info_size	= 2,
+	.ctx_arg_info		= {
+		{ offsetof(struct bpf_iter__task_file, task),
+		  PTR_TO_BTF_ID_OR_NULL },
+		{ offsetof(struct bpf_iter__task_file, file),
+		  PTR_TO_BTF_ID_OR_NULL },
+	},
+	.seq_info		= &task_file_seq_info,
+	.fill_link_info		= bpf_iter_fill_link_info,
+	.show_fdinfo		= bpf_iter_task_show_fdinfo,
+};
+
+static const struct bpf_iter_seq_info task_vma_seq_info = {
+	.seq_ops		= &task_vma_seq_ops,
+	.init_seq_private	= init_seq_pidns,
+	.fini_seq_private	= fini_seq_pidns,
+	.seq_priv_size		= sizeof(struct bpf_iter_seq_task_vma_info),
+};
+
+static struct bpf_iter_reg task_vma_reg_info = {
+	.target			= "task_vma",
+	.attach_target		= bpf_iter_attach_task,
+	.feature		= BPF_ITER_RESCHED,
+	.ctx_arg_info_size	= 2,
+	.ctx_arg_info		= {
+		{ offsetof(struct bpf_iter__task_vma, task),
+		  PTR_TO_BTF_ID_OR_NULL },
+		{ offsetof(struct bpf_iter__task_vma, vma),
+		  PTR_TO_BTF_ID_OR_NULL },
+	},
+	.seq_info		= &task_vma_seq_info,
+	.fill_link_info		= bpf_iter_fill_link_info,
+	.show_fdinfo		= bpf_iter_task_show_fdinfo,
+};
+
+BPF_CALL_5(bpf_find_vma, struct task_struct *, task, u64, start,
+	   bpf_callback_t, callback_fn, void *, callback_ctx, u64, flags)
+{
+	struct mmap_unlock_irq_work *work = NULL;
+	struct vm_area_struct *vma;
+	bool irq_work_busy = false;
+	struct mm_struct *mm;
+	int ret = -ENOENT;
+
+	if (flags)
+		return -EINVAL;
+
+	if (!task)
+		return -ENOENT;
+
+	mm = task->mm;
+	if (!mm)
+		return -ENOENT;
+
+	irq_work_busy = bpf_mmap_unlock_get_irq_work(&work);
+
+	if (irq_work_busy || !mmap_read_trylock(mm))
+		return -EBUSY;
+
+	vma = find_vma(mm, start);
+
+	if (vma && vma->vm_start <= start && vma->vm_end > start) {
+		callback_fn((u64)(long)task, (u64)(long)vma,
+			    (u64)(long)callback_ctx, 0, 0);
+		ret = 0;
+	}
+	bpf_mmap_unlock_mm(work, mm);
+	return ret;
+}
+
+const struct bpf_func_proto bpf_find_vma_proto = {
+	.func		= bpf_find_vma,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_BTF_ID,
+	.arg1_btf_id	= &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_PTR_TO_FUNC,
+	.arg4_type	= ARG_PTR_TO_STACK_OR_NULL,
+	.arg5_type	= ARG_ANYTHING,
+};
+
+DEFINE_PER_CPU(struct mmap_unlock_irq_work, mmap_unlock_work);
+
+static void do_mmap_read_unlock(struct irq_work *entry)
+{
+	struct mmap_unlock_irq_work *work;
+
+	if (WARN_ON_ONCE(IS_ENABLED(CONFIG_PREEMPT_RT)))
+		return;
+
+	work = container_of(entry, struct mmap_unlock_irq_work, irq_work);
+	mmap_read_unlock_non_owner(work->mm);
+}
+
+static int __init task_iter_init(void)
+{
+	struct mmap_unlock_irq_work *work;
+	int ret, cpu;
+
+	for_each_possible_cpu(cpu) {
+		work = per_cpu_ptr(&mmap_unlock_work, cpu);
+		init_irq_work(&work->irq_work, do_mmap_read_unlock);
+	}
+
+	task_reg_info.ctx_arg_info[0].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_TASK];
+	ret = bpf_iter_reg_target(&task_reg_info);
+	if (ret)
+		return ret;
+
+	task_file_reg_info.ctx_arg_info[0].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_TASK];
+	task_file_reg_info.ctx_arg_info[1].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_FILE];
+	ret =  bpf_iter_reg_target(&task_file_reg_info);
+	if (ret)
+		return ret;
+
+	task_vma_reg_info.ctx_arg_info[0].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_TASK];
+	task_vma_reg_info.ctx_arg_info[1].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_VMA];
+	return bpf_iter_reg_target(&task_vma_reg_info);
+}
+late_initcall(task_iter_init);
diff --git a/kernel/bpf/tnum.c b/kernel/bpf/tnum.c
new file mode 100644
index 000000000..3d7127f43
--- /dev/null
+++ b/kernel/bpf/tnum.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* tnum: tracked (or tristate) numbers
+ *
+ * A tnum tracks knowledge about the bits of a value.  Each bit can be either
+ * known (0 or 1), or unknown (x).  Arithmetic operations on tnums will
+ * propagate the unknown bits such that the tnum result represents all the
+ * possible results for possible values of the operands.
+ */
+#include <linux/kernel.h>
+#include <linux/tnum.h>
+
+#define TNUM(_v, _m)	(struct tnum){.value = _v, .mask = _m}
+/* A completely unknown value */
+const struct tnum tnum_unknown = { .value = 0, .mask = -1 };
+
+struct tnum tnum_const(u64 value)
+{
+	return TNUM(value, 0);
+}
+
+struct tnum tnum_range(u64 min, u64 max)
+{
+	u64 chi = min ^ max, delta;
+	u8 bits = fls64(chi);
+
+	/* special case, needed because 1ULL << 64 is undefined */
+	if (bits > 63)
+		return tnum_unknown;
+	/* e.g. if chi = 4, bits = 3, delta = (1<<3) - 1 = 7.
+	 * if chi = 0, bits = 0, delta = (1<<0) - 1 = 0, so we return
+	 *  constant min (since min == max).
+	 */
+	delta = (1ULL << bits) - 1;
+	return TNUM(min & ~delta, delta);
+}
+
+struct tnum tnum_lshift(struct tnum a, u8 shift)
+{
+	return TNUM(a.value << shift, a.mask << shift);
+}
+
+struct tnum tnum_rshift(struct tnum a, u8 shift)
+{
+	return TNUM(a.value >> shift, a.mask >> shift);
+}
+
+struct tnum tnum_arshift(struct tnum a, u8 min_shift, u8 insn_bitness)
+{
+	/* if a.value is negative, arithmetic shifting by minimum shift
+	 * will have larger negative offset compared to more shifting.
+	 * If a.value is nonnegative, arithmetic shifting by minimum shift
+	 * will have larger positive offset compare to more shifting.
+	 */
+	if (insn_bitness == 32)
+		return TNUM((u32)(((s32)a.value) >> min_shift),
+			    (u32)(((s32)a.mask)  >> min_shift));
+	else
+		return TNUM((s64)a.value >> min_shift,
+			    (s64)a.mask  >> min_shift);
+}
+
+struct tnum tnum_add(struct tnum a, struct tnum b)
+{
+	u64 sm, sv, sigma, chi, mu;
+
+	sm = a.mask + b.mask;
+	sv = a.value + b.value;
+	sigma = sm + sv;
+	chi = sigma ^ sv;
+	mu = chi | a.mask | b.mask;
+	return TNUM(sv & ~mu, mu);
+}
+
+struct tnum tnum_sub(struct tnum a, struct tnum b)
+{
+	u64 dv, alpha, beta, chi, mu;
+
+	dv = a.value - b.value;
+	alpha = dv + a.mask;
+	beta = dv - b.mask;
+	chi = alpha ^ beta;
+	mu = chi | a.mask | b.mask;
+	return TNUM(dv & ~mu, mu);
+}
+
+struct tnum tnum_and(struct tnum a, struct tnum b)
+{
+	u64 alpha, beta, v;
+
+	alpha = a.value | a.mask;
+	beta = b.value | b.mask;
+	v = a.value & b.value;
+	return TNUM(v, alpha & beta & ~v);
+}
+
+struct tnum tnum_or(struct tnum a, struct tnum b)
+{
+	u64 v, mu;
+
+	v = a.value | b.value;
+	mu = a.mask | b.mask;
+	return TNUM(v, mu & ~v);
+}
+
+struct tnum tnum_xor(struct tnum a, struct tnum b)
+{
+	u64 v, mu;
+
+	v = a.value ^ b.value;
+	mu = a.mask | b.mask;
+	return TNUM(v & ~mu, mu);
+}
+
+/* Generate partial products by multiplying each bit in the multiplier (tnum a)
+ * with the multiplicand (tnum b), and add the partial products after
+ * appropriately bit-shifting them. Instead of directly performing tnum addition
+ * on the generated partial products, equivalenty, decompose each partial
+ * product into two tnums, consisting of the value-sum (acc_v) and the
+ * mask-sum (acc_m) and then perform tnum addition on them. The following paper
+ * explains the algorithm in more detail: https://arxiv.org/abs/2105.05398.
+ */
+struct tnum tnum_mul(struct tnum a, struct tnum b)
+{
+	u64 acc_v = a.value * b.value;
+	struct tnum acc_m = TNUM(0, 0);
+
+	while (a.value || a.mask) {
+		/* LSB of tnum a is a certain 1 */
+		if (a.value & 1)
+			acc_m = tnum_add(acc_m, TNUM(0, b.mask));
+		/* LSB of tnum a is uncertain */
+		else if (a.mask & 1)
+			acc_m = tnum_add(acc_m, TNUM(0, b.value | b.mask));
+		/* Note: no case for LSB is certain 0 */
+		a = tnum_rshift(a, 1);
+		b = tnum_lshift(b, 1);
+	}
+	return tnum_add(TNUM(acc_v, 0), acc_m);
+}
+
+/* Note that if a and b disagree - i.e. one has a 'known 1' where the other has
+ * a 'known 0' - this will return a 'known 1' for that bit.
+ */
+struct tnum tnum_intersect(struct tnum a, struct tnum b)
+{
+	u64 v, mu;
+
+	v = a.value | b.value;
+	mu = a.mask & b.mask;
+	return TNUM(v & ~mu, mu);
+}
+
+struct tnum tnum_cast(struct tnum a, u8 size)
+{
+	a.value &= (1ULL << (size * 8)) - 1;
+	a.mask &= (1ULL << (size * 8)) - 1;
+	return a;
+}
+
+bool tnum_is_aligned(struct tnum a, u64 size)
+{
+	if (!size)
+		return true;
+	return !((a.value | a.mask) & (size - 1));
+}
+
+bool tnum_in(struct tnum a, struct tnum b)
+{
+	if (b.mask & ~a.mask)
+		return false;
+	b.value &= ~a.mask;
+	return a.value == b.value;
+}
+
+int tnum_strn(char *str, size_t size, struct tnum a)
+{
+	return snprintf(str, size, "(%#llx; %#llx)", a.value, a.mask);
+}
+EXPORT_SYMBOL_GPL(tnum_strn);
+
+int tnum_sbin(char *str, size_t size, struct tnum a)
+{
+	size_t n;
+
+	for (n = 64; n; n--) {
+		if (n < size) {
+			if (a.mask & 1)
+				str[n - 1] = 'x';
+			else if (a.value & 1)
+				str[n - 1] = '1';
+			else
+				str[n - 1] = '0';
+		}
+		a.mask >>= 1;
+		a.value >>= 1;
+	}
+	str[min(size - 1, (size_t)64)] = 0;
+	return 64;
+}
+
+struct tnum tnum_subreg(struct tnum a)
+{
+	return tnum_cast(a, 4);
+}
+
+struct tnum tnum_clear_subreg(struct tnum a)
+{
+	return tnum_lshift(tnum_rshift(a, 32), 32);
+}
+
+struct tnum tnum_const_subreg(struct tnum a, u32 value)
+{
+	return tnum_or(tnum_clear_subreg(a), tnum_const(value));
+}
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
new file mode 100644
index 000000000..748ac8616
--- /dev/null
+++ b/kernel/bpf/trampoline.c
@@ -0,0 +1,1080 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2019 Facebook */
+#include <linux/hash.h>
+#include <linux/bpf.h>
+#include <linux/filter.h>
+#include <linux/ftrace.h>
+#include <linux/rbtree_latch.h>
+#include <linux/perf_event.h>
+#include <linux/btf.h>
+#include <linux/rcupdate_trace.h>
+#include <linux/rcupdate_wait.h>
+#include <linux/module.h>
+#include <linux/static_call.h>
+#include <linux/bpf_verifier.h>
+#include <linux/bpf_lsm.h>
+#include <linux/delay.h>
+
+/* dummy _ops. The verifier will operate on target program's ops. */
+const struct bpf_verifier_ops bpf_extension_verifier_ops = {
+};
+const struct bpf_prog_ops bpf_extension_prog_ops = {
+};
+
+/* btf_vmlinux has ~22k attachable functions. 1k htab is enough. */
+#define TRAMPOLINE_HASH_BITS 10
+#define TRAMPOLINE_TABLE_SIZE (1 << TRAMPOLINE_HASH_BITS)
+
+static struct hlist_head trampoline_table[TRAMPOLINE_TABLE_SIZE];
+
+/* serializes access to trampoline_table */
+static DEFINE_MUTEX(trampoline_mutex);
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mutex);
+
+static int bpf_tramp_ftrace_ops_func(struct ftrace_ops *ops, enum ftrace_ops_cmd cmd)
+{
+	struct bpf_trampoline *tr = ops->private;
+	int ret = 0;
+
+	if (cmd == FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF) {
+		/* This is called inside register_ftrace_direct_multi(), so
+		 * tr->mutex is already locked.
+		 */
+		lockdep_assert_held_once(&tr->mutex);
+
+		/* Instead of updating the trampoline here, we propagate
+		 * -EAGAIN to register_ftrace_direct_multi(). Then we can
+		 * retry register_ftrace_direct_multi() after updating the
+		 * trampoline.
+		 */
+		if ((tr->flags & BPF_TRAMP_F_CALL_ORIG) &&
+		    !(tr->flags & BPF_TRAMP_F_ORIG_STACK)) {
+			if (WARN_ON_ONCE(tr->flags & BPF_TRAMP_F_SHARE_IPMODIFY))
+				return -EBUSY;
+
+			tr->flags |= BPF_TRAMP_F_SHARE_IPMODIFY;
+			return -EAGAIN;
+		}
+
+		return 0;
+	}
+
+	/* The normal locking order is
+	 *    tr->mutex => direct_mutex (ftrace.c) => ftrace_lock (ftrace.c)
+	 *
+	 * The following two commands are called from
+	 *
+	 *   prepare_direct_functions_for_ipmodify
+	 *   cleanup_direct_functions_after_ipmodify
+	 *
+	 * In both cases, direct_mutex is already locked. Use
+	 * mutex_trylock(&tr->mutex) to avoid deadlock in race condition
+	 * (something else is making changes to this same trampoline).
+	 */
+	if (!mutex_trylock(&tr->mutex)) {
+		/* sleep 1 ms to make sure whatever holding tr->mutex makes
+		 * some progress.
+		 */
+		msleep(1);
+		return -EAGAIN;
+	}
+
+	switch (cmd) {
+	case FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER:
+		tr->flags |= BPF_TRAMP_F_SHARE_IPMODIFY;
+
+		if ((tr->flags & BPF_TRAMP_F_CALL_ORIG) &&
+		    !(tr->flags & BPF_TRAMP_F_ORIG_STACK))
+			ret = bpf_trampoline_update(tr, false /* lock_direct_mutex */);
+		break;
+	case FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER:
+		tr->flags &= ~BPF_TRAMP_F_SHARE_IPMODIFY;
+
+		if (tr->flags & BPF_TRAMP_F_ORIG_STACK)
+			ret = bpf_trampoline_update(tr, false /* lock_direct_mutex */);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	mutex_unlock(&tr->mutex);
+	return ret;
+}
+#endif
+
+bool bpf_prog_has_trampoline(const struct bpf_prog *prog)
+{
+	enum bpf_attach_type eatype = prog->expected_attach_type;
+	enum bpf_prog_type ptype = prog->type;
+
+	return (ptype == BPF_PROG_TYPE_TRACING &&
+		(eatype == BPF_TRACE_FENTRY || eatype == BPF_TRACE_FEXIT ||
+		 eatype == BPF_MODIFY_RETURN)) ||
+		(ptype == BPF_PROG_TYPE_LSM && eatype == BPF_LSM_MAC);
+}
+
+void bpf_image_ksym_add(void *data, struct bpf_ksym *ksym)
+{
+	ksym->start = (unsigned long) data;
+	ksym->end = ksym->start + PAGE_SIZE;
+	bpf_ksym_add(ksym);
+	perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, ksym->start,
+			   PAGE_SIZE, false, ksym->name);
+}
+
+void bpf_image_ksym_del(struct bpf_ksym *ksym)
+{
+	bpf_ksym_del(ksym);
+	perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, ksym->start,
+			   PAGE_SIZE, true, ksym->name);
+}
+
+static struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
+{
+	struct bpf_trampoline *tr;
+	struct hlist_head *head;
+	int i;
+
+	mutex_lock(&trampoline_mutex);
+	head = &trampoline_table[hash_64(key, TRAMPOLINE_HASH_BITS)];
+	hlist_for_each_entry(tr, head, hlist) {
+		if (tr->key == key) {
+			refcount_inc(&tr->refcnt);
+			goto out;
+		}
+	}
+	tr = kzalloc(sizeof(*tr), GFP_KERNEL);
+	if (!tr)
+		goto out;
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	tr->fops = kzalloc(sizeof(struct ftrace_ops), GFP_KERNEL);
+	if (!tr->fops) {
+		kfree(tr);
+		tr = NULL;
+		goto out;
+	}
+	tr->fops->private = tr;
+	tr->fops->ops_func = bpf_tramp_ftrace_ops_func;
+#endif
+
+	tr->key = key;
+	INIT_HLIST_NODE(&tr->hlist);
+	hlist_add_head(&tr->hlist, head);
+	refcount_set(&tr->refcnt, 1);
+	mutex_init(&tr->mutex);
+	for (i = 0; i < BPF_TRAMP_MAX; i++)
+		INIT_HLIST_HEAD(&tr->progs_hlist[i]);
+out:
+	mutex_unlock(&trampoline_mutex);
+	return tr;
+}
+
+static int bpf_trampoline_module_get(struct bpf_trampoline *tr)
+{
+	struct module *mod;
+	int err = 0;
+
+	preempt_disable();
+	mod = __module_text_address((unsigned long) tr->func.addr);
+	if (mod && !try_module_get(mod))
+		err = -ENOENT;
+	preempt_enable();
+	tr->mod = mod;
+	return err;
+}
+
+static void bpf_trampoline_module_put(struct bpf_trampoline *tr)
+{
+	module_put(tr->mod);
+	tr->mod = NULL;
+}
+
+static int unregister_fentry(struct bpf_trampoline *tr, void *old_addr)
+{
+	void *ip = tr->func.addr;
+	int ret;
+
+	if (tr->func.ftrace_managed)
+		ret = unregister_ftrace_direct_multi(tr->fops, (long)old_addr);
+	else
+		ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, old_addr, NULL);
+
+	if (!ret)
+		bpf_trampoline_module_put(tr);
+	return ret;
+}
+
+static int modify_fentry(struct bpf_trampoline *tr, void *old_addr, void *new_addr,
+			 bool lock_direct_mutex)
+{
+	void *ip = tr->func.addr;
+	int ret;
+
+	if (tr->func.ftrace_managed) {
+		if (lock_direct_mutex)
+			ret = modify_ftrace_direct_multi(tr->fops, (long)new_addr);
+		else
+			ret = modify_ftrace_direct_multi_nolock(tr->fops, (long)new_addr);
+	} else {
+		ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, old_addr, new_addr);
+	}
+	return ret;
+}
+
+/* first time registering */
+static int register_fentry(struct bpf_trampoline *tr, void *new_addr)
+{
+	void *ip = tr->func.addr;
+	unsigned long faddr;
+	int ret;
+
+	faddr = ftrace_location((unsigned long)ip);
+	if (faddr) {
+		if (!tr->fops)
+			return -ENOTSUPP;
+		tr->func.ftrace_managed = true;
+	}
+
+	if (bpf_trampoline_module_get(tr))
+		return -ENOENT;
+
+	if (tr->func.ftrace_managed) {
+		ftrace_set_filter_ip(tr->fops, (unsigned long)ip, 0, 1);
+		ret = register_ftrace_direct_multi(tr->fops, (long)new_addr);
+	} else {
+		ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, NULL, new_addr);
+	}
+
+	if (ret)
+		bpf_trampoline_module_put(tr);
+	return ret;
+}
+
+static struct bpf_tramp_links *
+bpf_trampoline_get_progs(const struct bpf_trampoline *tr, int *total, bool *ip_arg)
+{
+	struct bpf_tramp_link *link;
+	struct bpf_tramp_links *tlinks;
+	struct bpf_tramp_link **links;
+	int kind;
+
+	*total = 0;
+	tlinks = kcalloc(BPF_TRAMP_MAX, sizeof(*tlinks), GFP_KERNEL);
+	if (!tlinks)
+		return ERR_PTR(-ENOMEM);
+
+	for (kind = 0; kind < BPF_TRAMP_MAX; kind++) {
+		tlinks[kind].nr_links = tr->progs_cnt[kind];
+		*total += tr->progs_cnt[kind];
+		links = tlinks[kind].links;
+
+		hlist_for_each_entry(link, &tr->progs_hlist[kind], tramp_hlist) {
+			*ip_arg |= link->link.prog->call_get_func_ip;
+			*links++ = link;
+		}
+	}
+	return tlinks;
+}
+
+static void bpf_tramp_image_free(struct bpf_tramp_image *im)
+{
+	bpf_image_ksym_del(&im->ksym);
+	bpf_jit_free_exec(im->image);
+	bpf_jit_uncharge_modmem(PAGE_SIZE);
+	percpu_ref_exit(&im->pcref);
+	kfree_rcu(im, rcu);
+}
+
+static void __bpf_tramp_image_put_deferred(struct work_struct *work)
+{
+	struct bpf_tramp_image *im;
+
+	im = container_of(work, struct bpf_tramp_image, work);
+	bpf_tramp_image_free(im);
+}
+
+/* callback, fexit step 3 or fentry step 2 */
+static void __bpf_tramp_image_put_rcu(struct rcu_head *rcu)
+{
+	struct bpf_tramp_image *im;
+
+	im = container_of(rcu, struct bpf_tramp_image, rcu);
+	INIT_WORK(&im->work, __bpf_tramp_image_put_deferred);
+	schedule_work(&im->work);
+}
+
+/* callback, fexit step 2. Called after percpu_ref_kill confirms. */
+static void __bpf_tramp_image_release(struct percpu_ref *pcref)
+{
+	struct bpf_tramp_image *im;
+
+	im = container_of(pcref, struct bpf_tramp_image, pcref);
+	call_rcu_tasks(&im->rcu, __bpf_tramp_image_put_rcu);
+}
+
+/* callback, fexit or fentry step 1 */
+static void __bpf_tramp_image_put_rcu_tasks(struct rcu_head *rcu)
+{
+	struct bpf_tramp_image *im;
+
+	im = container_of(rcu, struct bpf_tramp_image, rcu);
+	if (im->ip_after_call)
+		/* the case of fmod_ret/fexit trampoline and CONFIG_PREEMPTION=y */
+		percpu_ref_kill(&im->pcref);
+	else
+		/* the case of fentry trampoline */
+		call_rcu_tasks(&im->rcu, __bpf_tramp_image_put_rcu);
+}
+
+static void bpf_tramp_image_put(struct bpf_tramp_image *im)
+{
+	/* The trampoline image that calls original function is using:
+	 * rcu_read_lock_trace to protect sleepable bpf progs
+	 * rcu_read_lock to protect normal bpf progs
+	 * percpu_ref to protect trampoline itself
+	 * rcu tasks to protect trampoline asm not covered by percpu_ref
+	 * (which are few asm insns before __bpf_tramp_enter and
+	 *  after __bpf_tramp_exit)
+	 *
+	 * The trampoline is unreachable before bpf_tramp_image_put().
+	 *
+	 * First, patch the trampoline to avoid calling into fexit progs.
+	 * The progs will be freed even if the original function is still
+	 * executing or sleeping.
+	 * In case of CONFIG_PREEMPT=y use call_rcu_tasks() to wait on
+	 * first few asm instructions to execute and call into
+	 * __bpf_tramp_enter->percpu_ref_get.
+	 * Then use percpu_ref_kill to wait for the trampoline and the original
+	 * function to finish.
+	 * Then use call_rcu_tasks() to make sure few asm insns in
+	 * the trampoline epilogue are done as well.
+	 *
+	 * In !PREEMPT case the task that got interrupted in the first asm
+	 * insns won't go through an RCU quiescent state which the
+	 * percpu_ref_kill will be waiting for. Hence the first
+	 * call_rcu_tasks() is not necessary.
+	 */
+	if (im->ip_after_call) {
+		int err = bpf_arch_text_poke(im->ip_after_call, BPF_MOD_JUMP,
+					     NULL, im->ip_epilogue);
+		WARN_ON(err);
+		if (IS_ENABLED(CONFIG_PREEMPTION))
+			call_rcu_tasks(&im->rcu, __bpf_tramp_image_put_rcu_tasks);
+		else
+			percpu_ref_kill(&im->pcref);
+		return;
+	}
+
+	/* The trampoline without fexit and fmod_ret progs doesn't call original
+	 * function and doesn't use percpu_ref.
+	 * Use call_rcu_tasks_trace() to wait for sleepable progs to finish.
+	 * Then use call_rcu_tasks() to wait for the rest of trampoline asm
+	 * and normal progs.
+	 */
+	call_rcu_tasks_trace(&im->rcu, __bpf_tramp_image_put_rcu_tasks);
+}
+
+static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key)
+{
+	struct bpf_tramp_image *im;
+	struct bpf_ksym *ksym;
+	void *image;
+	int err = -ENOMEM;
+
+	im = kzalloc(sizeof(*im), GFP_KERNEL);
+	if (!im)
+		goto out;
+
+	err = bpf_jit_charge_modmem(PAGE_SIZE);
+	if (err)
+		goto out_free_im;
+
+	err = -ENOMEM;
+	im->image = image = bpf_jit_alloc_exec(PAGE_SIZE);
+	if (!image)
+		goto out_uncharge;
+	set_vm_flush_reset_perms(image);
+
+	err = percpu_ref_init(&im->pcref, __bpf_tramp_image_release, 0, GFP_KERNEL);
+	if (err)
+		goto out_free_image;
+
+	ksym = &im->ksym;
+	INIT_LIST_HEAD_RCU(&ksym->lnode);
+	snprintf(ksym->name, KSYM_NAME_LEN, "bpf_trampoline_%llu", key);
+	bpf_image_ksym_add(image, ksym);
+	return im;
+
+out_free_image:
+	bpf_jit_free_exec(im->image);
+out_uncharge:
+	bpf_jit_uncharge_modmem(PAGE_SIZE);
+out_free_im:
+	kfree(im);
+out:
+	return ERR_PTR(err);
+}
+
+static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mutex)
+{
+	struct bpf_tramp_image *im;
+	struct bpf_tramp_links *tlinks;
+	u32 orig_flags = tr->flags;
+	bool ip_arg = false;
+	int err, total;
+
+	tlinks = bpf_trampoline_get_progs(tr, &total, &ip_arg);
+	if (IS_ERR(tlinks))
+		return PTR_ERR(tlinks);
+
+	if (total == 0) {
+		err = unregister_fentry(tr, tr->cur_image->image);
+		bpf_tramp_image_put(tr->cur_image);
+		tr->cur_image = NULL;
+		goto out;
+	}
+
+	im = bpf_tramp_image_alloc(tr->key);
+	if (IS_ERR(im)) {
+		err = PTR_ERR(im);
+		goto out;
+	}
+
+	/* clear all bits except SHARE_IPMODIFY and TAIL_CALL_CTX */
+	tr->flags &= (BPF_TRAMP_F_SHARE_IPMODIFY | BPF_TRAMP_F_TAIL_CALL_CTX);
+
+	if (tlinks[BPF_TRAMP_FEXIT].nr_links ||
+	    tlinks[BPF_TRAMP_MODIFY_RETURN].nr_links) {
+		/* NOTE: BPF_TRAMP_F_RESTORE_REGS and BPF_TRAMP_F_SKIP_FRAME
+		 * should not be set together.
+		 */
+		tr->flags |= BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_SKIP_FRAME;
+	} else {
+		tr->flags |= BPF_TRAMP_F_RESTORE_REGS;
+	}
+
+	if (ip_arg)
+		tr->flags |= BPF_TRAMP_F_IP_ARG;
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+again:
+	if ((tr->flags & BPF_TRAMP_F_SHARE_IPMODIFY) &&
+	    (tr->flags & BPF_TRAMP_F_CALL_ORIG))
+		tr->flags |= BPF_TRAMP_F_ORIG_STACK;
+#endif
+
+	err = arch_prepare_bpf_trampoline(im, im->image, im->image + PAGE_SIZE,
+					  &tr->func.model, tr->flags, tlinks,
+					  tr->func.addr);
+	if (err < 0)
+		goto out_free;
+
+	set_memory_ro((long)im->image, 1);
+	set_memory_x((long)im->image, 1);
+
+	WARN_ON(tr->cur_image && total == 0);
+	if (tr->cur_image)
+		/* progs already running at this address */
+		err = modify_fentry(tr, tr->cur_image->image, im->image, lock_direct_mutex);
+	else
+		/* first time registering */
+		err = register_fentry(tr, im->image);
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	if (err == -EAGAIN) {
+		/* -EAGAIN from bpf_tramp_ftrace_ops_func. Now
+		 * BPF_TRAMP_F_SHARE_IPMODIFY is set, we can generate the
+		 * trampoline again, and retry register.
+		 */
+		/* reset fops->func and fops->trampoline for re-register */
+		tr->fops->func = NULL;
+		tr->fops->trampoline = 0;
+
+		/* reset im->image memory attr for arch_prepare_bpf_trampoline */
+		set_memory_nx((long)im->image, 1);
+		set_memory_rw((long)im->image, 1);
+		goto again;
+	}
+#endif
+	if (err)
+		goto out_free;
+
+	if (tr->cur_image)
+		bpf_tramp_image_put(tr->cur_image);
+	tr->cur_image = im;
+out:
+	/* If any error happens, restore previous flags */
+	if (err)
+		tr->flags = orig_flags;
+	kfree(tlinks);
+	return err;
+
+out_free:
+	bpf_tramp_image_free(im);
+	goto out;
+}
+
+static enum bpf_tramp_prog_type bpf_attach_type_to_tramp(struct bpf_prog *prog)
+{
+	switch (prog->expected_attach_type) {
+	case BPF_TRACE_FENTRY:
+		return BPF_TRAMP_FENTRY;
+	case BPF_MODIFY_RETURN:
+		return BPF_TRAMP_MODIFY_RETURN;
+	case BPF_TRACE_FEXIT:
+		return BPF_TRAMP_FEXIT;
+	case BPF_LSM_MAC:
+		if (!prog->aux->attach_func_proto->type)
+			/* The function returns void, we cannot modify its
+			 * return value.
+			 */
+			return BPF_TRAMP_FEXIT;
+		else
+			return BPF_TRAMP_MODIFY_RETURN;
+	default:
+		return BPF_TRAMP_REPLACE;
+	}
+}
+
+static int __bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
+{
+	enum bpf_tramp_prog_type kind;
+	struct bpf_tramp_link *link_exiting;
+	int err = 0;
+	int cnt = 0, i;
+
+	kind = bpf_attach_type_to_tramp(link->link.prog);
+	if (tr->extension_prog)
+		/* cannot attach fentry/fexit if extension prog is attached.
+		 * cannot overwrite extension prog either.
+		 */
+		return -EBUSY;
+
+	for (i = 0; i < BPF_TRAMP_MAX; i++)
+		cnt += tr->progs_cnt[i];
+
+	if (kind == BPF_TRAMP_REPLACE) {
+		/* Cannot attach extension if fentry/fexit are in use. */
+		if (cnt)
+			return -EBUSY;
+		tr->extension_prog = link->link.prog;
+		return bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP, NULL,
+					  link->link.prog->bpf_func);
+	}
+	if (cnt >= BPF_MAX_TRAMP_LINKS)
+		return -E2BIG;
+	if (!hlist_unhashed(&link->tramp_hlist))
+		/* prog already linked */
+		return -EBUSY;
+	hlist_for_each_entry(link_exiting, &tr->progs_hlist[kind], tramp_hlist) {
+		if (link_exiting->link.prog != link->link.prog)
+			continue;
+		/* prog already linked */
+		return -EBUSY;
+	}
+
+	hlist_add_head(&link->tramp_hlist, &tr->progs_hlist[kind]);
+	tr->progs_cnt[kind]++;
+	err = bpf_trampoline_update(tr, true /* lock_direct_mutex */);
+	if (err) {
+		hlist_del_init(&link->tramp_hlist);
+		tr->progs_cnt[kind]--;
+	}
+	return err;
+}
+
+int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
+{
+	int err;
+
+	mutex_lock(&tr->mutex);
+	err = __bpf_trampoline_link_prog(link, tr);
+	mutex_unlock(&tr->mutex);
+	return err;
+}
+
+static int __bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
+{
+	enum bpf_tramp_prog_type kind;
+	int err;
+
+	kind = bpf_attach_type_to_tramp(link->link.prog);
+	if (kind == BPF_TRAMP_REPLACE) {
+		WARN_ON_ONCE(!tr->extension_prog);
+		err = bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP,
+					 tr->extension_prog->bpf_func, NULL);
+		tr->extension_prog = NULL;
+		return err;
+	}
+	hlist_del_init(&link->tramp_hlist);
+	tr->progs_cnt[kind]--;
+	return bpf_trampoline_update(tr, true /* lock_direct_mutex */);
+}
+
+/* bpf_trampoline_unlink_prog() should never fail. */
+int bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
+{
+	int err;
+
+	mutex_lock(&tr->mutex);
+	err = __bpf_trampoline_unlink_prog(link, tr);
+	mutex_unlock(&tr->mutex);
+	return err;
+}
+
+#if defined(CONFIG_CGROUP_BPF) && defined(CONFIG_BPF_LSM)
+static void bpf_shim_tramp_link_release(struct bpf_link *link)
+{
+	struct bpf_shim_tramp_link *shim_link =
+		container_of(link, struct bpf_shim_tramp_link, link.link);
+
+	/* paired with 'shim_link->trampoline = tr' in bpf_trampoline_link_cgroup_shim */
+	if (!shim_link->trampoline)
+		return;
+
+	WARN_ON_ONCE(bpf_trampoline_unlink_prog(&shim_link->link, shim_link->trampoline));
+	bpf_trampoline_put(shim_link->trampoline);
+}
+
+static void bpf_shim_tramp_link_dealloc(struct bpf_link *link)
+{
+	struct bpf_shim_tramp_link *shim_link =
+		container_of(link, struct bpf_shim_tramp_link, link.link);
+
+	kfree(shim_link);
+}
+
+static const struct bpf_link_ops bpf_shim_tramp_link_lops = {
+	.release = bpf_shim_tramp_link_release,
+	.dealloc = bpf_shim_tramp_link_dealloc,
+};
+
+static struct bpf_shim_tramp_link *cgroup_shim_alloc(const struct bpf_prog *prog,
+						     bpf_func_t bpf_func,
+						     int cgroup_atype)
+{
+	struct bpf_shim_tramp_link *shim_link = NULL;
+	struct bpf_prog *p;
+
+	shim_link = kzalloc(sizeof(*shim_link), GFP_USER);
+	if (!shim_link)
+		return NULL;
+
+	p = bpf_prog_alloc(1, 0);
+	if (!p) {
+		kfree(shim_link);
+		return NULL;
+	}
+
+	p->jited = false;
+	p->bpf_func = bpf_func;
+
+	p->aux->cgroup_atype = cgroup_atype;
+	p->aux->attach_func_proto = prog->aux->attach_func_proto;
+	p->aux->attach_btf_id = prog->aux->attach_btf_id;
+	p->aux->attach_btf = prog->aux->attach_btf;
+	btf_get(p->aux->attach_btf);
+	p->type = BPF_PROG_TYPE_LSM;
+	p->expected_attach_type = BPF_LSM_MAC;
+	bpf_prog_inc(p);
+	bpf_link_init(&shim_link->link.link, BPF_LINK_TYPE_UNSPEC,
+		      &bpf_shim_tramp_link_lops, p);
+	bpf_cgroup_atype_get(p->aux->attach_btf_id, cgroup_atype);
+
+	return shim_link;
+}
+
+static struct bpf_shim_tramp_link *cgroup_shim_find(struct bpf_trampoline *tr,
+						    bpf_func_t bpf_func)
+{
+	struct bpf_tramp_link *link;
+	int kind;
+
+	for (kind = 0; kind < BPF_TRAMP_MAX; kind++) {
+		hlist_for_each_entry(link, &tr->progs_hlist[kind], tramp_hlist) {
+			struct bpf_prog *p = link->link.prog;
+
+			if (p->bpf_func == bpf_func)
+				return container_of(link, struct bpf_shim_tramp_link, link);
+		}
+	}
+
+	return NULL;
+}
+
+int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog,
+				    int cgroup_atype)
+{
+	struct bpf_shim_tramp_link *shim_link = NULL;
+	struct bpf_attach_target_info tgt_info = {};
+	struct bpf_trampoline *tr;
+	bpf_func_t bpf_func;
+	u64 key;
+	int err;
+
+	err = bpf_check_attach_target(NULL, prog, NULL,
+				      prog->aux->attach_btf_id,
+				      &tgt_info);
+	if (err)
+		return err;
+
+	key = bpf_trampoline_compute_key(NULL, prog->aux->attach_btf,
+					 prog->aux->attach_btf_id);
+
+	bpf_lsm_find_cgroup_shim(prog, &bpf_func);
+	tr = bpf_trampoline_get(key, &tgt_info);
+	if (!tr)
+		return  -ENOMEM;
+
+	mutex_lock(&tr->mutex);
+
+	shim_link = cgroup_shim_find(tr, bpf_func);
+	if (shim_link) {
+		/* Reusing existing shim attached by the other program. */
+		bpf_link_inc(&shim_link->link.link);
+
+		mutex_unlock(&tr->mutex);
+		bpf_trampoline_put(tr); /* bpf_trampoline_get above */
+		return 0;
+	}
+
+	/* Allocate and install new shim. */
+
+	shim_link = cgroup_shim_alloc(prog, bpf_func, cgroup_atype);
+	if (!shim_link) {
+		err = -ENOMEM;
+		goto err;
+	}
+
+	err = __bpf_trampoline_link_prog(&shim_link->link, tr);
+	if (err)
+		goto err;
+
+	shim_link->trampoline = tr;
+	/* note, we're still holding tr refcnt from above */
+
+	mutex_unlock(&tr->mutex);
+
+	return 0;
+err:
+	mutex_unlock(&tr->mutex);
+
+	if (shim_link)
+		bpf_link_put(&shim_link->link.link);
+
+	/* have to release tr while _not_ holding its mutex */
+	bpf_trampoline_put(tr); /* bpf_trampoline_get above */
+
+	return err;
+}
+
+void bpf_trampoline_unlink_cgroup_shim(struct bpf_prog *prog)
+{
+	struct bpf_shim_tramp_link *shim_link = NULL;
+	struct bpf_trampoline *tr;
+	bpf_func_t bpf_func;
+	u64 key;
+
+	key = bpf_trampoline_compute_key(NULL, prog->aux->attach_btf,
+					 prog->aux->attach_btf_id);
+
+	bpf_lsm_find_cgroup_shim(prog, &bpf_func);
+	tr = bpf_trampoline_lookup(key);
+	if (WARN_ON_ONCE(!tr))
+		return;
+
+	mutex_lock(&tr->mutex);
+	shim_link = cgroup_shim_find(tr, bpf_func);
+	mutex_unlock(&tr->mutex);
+
+	if (shim_link)
+		bpf_link_put(&shim_link->link.link);
+
+	bpf_trampoline_put(tr); /* bpf_trampoline_lookup above */
+}
+#endif
+
+struct bpf_trampoline *bpf_trampoline_get(u64 key,
+					  struct bpf_attach_target_info *tgt_info)
+{
+	struct bpf_trampoline *tr;
+
+	tr = bpf_trampoline_lookup(key);
+	if (!tr)
+		return NULL;
+
+	mutex_lock(&tr->mutex);
+	if (tr->func.addr)
+		goto out;
+
+	memcpy(&tr->func.model, &tgt_info->fmodel, sizeof(tgt_info->fmodel));
+	tr->func.addr = (void *)tgt_info->tgt_addr;
+out:
+	mutex_unlock(&tr->mutex);
+	return tr;
+}
+
+void bpf_trampoline_put(struct bpf_trampoline *tr)
+{
+	int i;
+
+	if (!tr)
+		return;
+	mutex_lock(&trampoline_mutex);
+	if (!refcount_dec_and_test(&tr->refcnt))
+		goto out;
+	WARN_ON_ONCE(mutex_is_locked(&tr->mutex));
+
+	for (i = 0; i < BPF_TRAMP_MAX; i++)
+		if (WARN_ON_ONCE(!hlist_empty(&tr->progs_hlist[i])))
+			goto out;
+
+	/* This code will be executed even when the last bpf_tramp_image
+	 * is alive. All progs are detached from the trampoline and the
+	 * trampoline image is patched with jmp into epilogue to skip
+	 * fexit progs. The fentry-only trampoline will be freed via
+	 * multiple rcu callbacks.
+	 */
+	hlist_del(&tr->hlist);
+	if (tr->fops) {
+		ftrace_free_filter(tr->fops);
+		kfree(tr->fops);
+	}
+	kfree(tr);
+out:
+	mutex_unlock(&trampoline_mutex);
+}
+
+#define NO_START_TIME 1
+static __always_inline u64 notrace bpf_prog_start_time(void)
+{
+	u64 start = NO_START_TIME;
+
+	if (static_branch_unlikely(&bpf_stats_enabled_key)) {
+		start = sched_clock();
+		if (unlikely(!start))
+			start = NO_START_TIME;
+	}
+	return start;
+}
+
+/* The logic is similar to bpf_prog_run(), but with an explicit
+ * rcu_read_lock() and migrate_disable() which are required
+ * for the trampoline. The macro is split into
+ * call __bpf_prog_enter
+ * call prog->bpf_func
+ * call __bpf_prog_exit
+ *
+ * __bpf_prog_enter returns:
+ * 0 - skip execution of the bpf prog
+ * 1 - execute bpf prog
+ * [2..MAX_U64] - execute bpf prog and record execution time.
+ *     This is start time.
+ */
+static u64 notrace __bpf_prog_enter_recur(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx)
+	__acquires(RCU)
+{
+	rcu_read_lock();
+	migrate_disable();
+
+	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
+	if (unlikely(this_cpu_inc_return(*(prog->active)) != 1)) {
+		bpf_prog_inc_misses_counter(prog);
+		return 0;
+	}
+	return bpf_prog_start_time();
+}
+
+static void notrace update_prog_stats(struct bpf_prog *prog,
+				      u64 start)
+{
+	struct bpf_prog_stats *stats;
+
+	if (static_branch_unlikely(&bpf_stats_enabled_key) &&
+	    /* static_key could be enabled in __bpf_prog_enter*
+	     * and disabled in __bpf_prog_exit*.
+	     * And vice versa.
+	     * Hence check that 'start' is valid.
+	     */
+	    start > NO_START_TIME) {
+		unsigned long flags;
+
+		stats = this_cpu_ptr(prog->stats);
+		flags = u64_stats_update_begin_irqsave(&stats->syncp);
+		u64_stats_inc(&stats->cnt);
+		u64_stats_add(&stats->nsecs, sched_clock() - start);
+		u64_stats_update_end_irqrestore(&stats->syncp, flags);
+	}
+}
+
+static void notrace __bpf_prog_exit_recur(struct bpf_prog *prog, u64 start,
+					  struct bpf_tramp_run_ctx *run_ctx)
+	__releases(RCU)
+{
+	bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
+	update_prog_stats(prog, start);
+	this_cpu_dec(*(prog->active));
+	migrate_enable();
+	rcu_read_unlock();
+}
+
+static u64 notrace __bpf_prog_enter_lsm_cgroup(struct bpf_prog *prog,
+					       struct bpf_tramp_run_ctx *run_ctx)
+	__acquires(RCU)
+{
+	/* Runtime stats are exported via actual BPF_LSM_CGROUP
+	 * programs, not the shims.
+	 */
+	rcu_read_lock();
+	migrate_disable();
+
+	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
+	return NO_START_TIME;
+}
+
+static void notrace __bpf_prog_exit_lsm_cgroup(struct bpf_prog *prog, u64 start,
+					       struct bpf_tramp_run_ctx *run_ctx)
+	__releases(RCU)
+{
+	bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
+	migrate_enable();
+	rcu_read_unlock();
+}
+
+u64 notrace __bpf_prog_enter_sleepable_recur(struct bpf_prog *prog,
+					     struct bpf_tramp_run_ctx *run_ctx)
+{
+	rcu_read_lock_trace();
+	migrate_disable();
+	might_fault();
+
+	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
+	if (unlikely(this_cpu_inc_return(*(prog->active)) != 1)) {
+		bpf_prog_inc_misses_counter(prog);
+		return 0;
+	}
+	return bpf_prog_start_time();
+}
+
+void notrace __bpf_prog_exit_sleepable_recur(struct bpf_prog *prog, u64 start,
+					     struct bpf_tramp_run_ctx *run_ctx)
+{
+	bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
+	update_prog_stats(prog, start);
+	this_cpu_dec(*(prog->active));
+	migrate_enable();
+	rcu_read_unlock_trace();
+}
+
+static u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog,
+					      struct bpf_tramp_run_ctx *run_ctx)
+{
+	rcu_read_lock_trace();
+	migrate_disable();
+	might_fault();
+
+	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
+	return bpf_prog_start_time();
+}
+
+static void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start,
+					      struct bpf_tramp_run_ctx *run_ctx)
+{
+	bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
+	update_prog_stats(prog, start);
+	migrate_enable();
+	rcu_read_unlock_trace();
+}
+
+static u64 notrace __bpf_prog_enter(struct bpf_prog *prog,
+				    struct bpf_tramp_run_ctx *run_ctx)
+	__acquires(RCU)
+{
+	rcu_read_lock();
+	migrate_disable();
+
+	run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
+	return bpf_prog_start_time();
+}
+
+static void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start,
+				    struct bpf_tramp_run_ctx *run_ctx)
+	__releases(RCU)
+{
+	bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
+	update_prog_stats(prog, start);
+	migrate_enable();
+	rcu_read_unlock();
+}
+
+void notrace __bpf_tramp_enter(struct bpf_tramp_image *tr)
+{
+	percpu_ref_get(&tr->pcref);
+}
+
+void notrace __bpf_tramp_exit(struct bpf_tramp_image *tr)
+{
+	percpu_ref_put(&tr->pcref);
+}
+
+bpf_trampoline_enter_t bpf_trampoline_enter(const struct bpf_prog *prog)
+{
+	bool sleepable = prog->aux->sleepable;
+
+	if (bpf_prog_check_recur(prog))
+		return sleepable ? __bpf_prog_enter_sleepable_recur :
+			__bpf_prog_enter_recur;
+
+	if (resolve_prog_type(prog) == BPF_PROG_TYPE_LSM &&
+	    prog->expected_attach_type == BPF_LSM_CGROUP)
+		return __bpf_prog_enter_lsm_cgroup;
+
+	return sleepable ? __bpf_prog_enter_sleepable : __bpf_prog_enter;
+}
+
+bpf_trampoline_exit_t bpf_trampoline_exit(const struct bpf_prog *prog)
+{
+	bool sleepable = prog->aux->sleepable;
+
+	if (bpf_prog_check_recur(prog))
+		return sleepable ? __bpf_prog_exit_sleepable_recur :
+			__bpf_prog_exit_recur;
+
+	if (resolve_prog_type(prog) == BPF_PROG_TYPE_LSM &&
+	    prog->expected_attach_type == BPF_LSM_CGROUP)
+		return __bpf_prog_exit_lsm_cgroup;
+
+	return sleepable ? __bpf_prog_exit_sleepable : __bpf_prog_exit;
+}
+
+int __weak
+arch_prepare_bpf_trampoline(struct bpf_tramp_image *tr, void *image, void *image_end,
+			    const struct btf_func_model *m, u32 flags,
+			    struct bpf_tramp_links *tlinks,
+			    void *orig_call)
+{
+	return -ENOTSUPP;
+}
+
+static int __init init_trampolines(void)
+{
+	int i;
+
+	for (i = 0; i < TRAMPOLINE_TABLE_SIZE; i++)
+		INIT_HLIST_HEAD(&trampoline_table[i]);
+	return 0;
+}
+late_initcall(init_trampolines);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
new file mode 100644
index 000000000..23b6d57b5
--- /dev/null
+++ b/kernel/bpf/verifier.c
@@ -0,0 +1,15761 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ * Copyright (c) 2016 Facebook
+ * Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
+ */
+#include <uapi/linux/btf.h>
+#include <linux/bpf-cgroup.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/bpf_verifier.h>
+#include <linux/filter.h>
+#include <net/netlink.h>
+#include <linux/file.h>
+#include <linux/vmalloc.h>
+#include <linux/stringify.h>
+#include <linux/bsearch.h>
+#include <linux/sort.h>
+#include <linux/perf_event.h>
+#include <linux/ctype.h>
+#include <linux/error-injection.h>
+#include <linux/bpf_lsm.h>
+#include <linux/btf_ids.h>
+#include <linux/poison.h>
+
+#include "disasm.h"
+
+static const struct bpf_verifier_ops * const bpf_verifier_ops[] = {
+#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
+	[_id] = & _name ## _verifier_ops,
+#define BPF_MAP_TYPE(_id, _ops)
+#define BPF_LINK_TYPE(_id, _name)
+#include <linux/bpf_types.h>
+#undef BPF_PROG_TYPE
+#undef BPF_MAP_TYPE
+#undef BPF_LINK_TYPE
+};
+
+/* bpf_check() is a static code analyzer that walks eBPF program
+ * instruction by instruction and updates register/stack state.
+ * All paths of conditional branches are analyzed until 'bpf_exit' insn.
+ *
+ * The first pass is depth-first-search to check that the program is a DAG.
+ * It rejects the following programs:
+ * - larger than BPF_MAXINSNS insns
+ * - if loop is present (detected via back-edge)
+ * - unreachable insns exist (shouldn't be a forest. program = one function)
+ * - out of bounds or malformed jumps
+ * The second pass is all possible path descent from the 1st insn.
+ * Since it's analyzing all paths through the program, the length of the
+ * analysis is limited to 64k insn, which may be hit even if total number of
+ * insn is less then 4K, but there are too many branches that change stack/regs.
+ * Number of 'branches to be analyzed' is limited to 1k
+ *
+ * On entry to each instruction, each register has a type, and the instruction
+ * changes the types of the registers depending on instruction semantics.
+ * If instruction is BPF_MOV64_REG(BPF_REG_1, BPF_REG_5), then type of R5 is
+ * copied to R1.
+ *
+ * All registers are 64-bit.
+ * R0 - return register
+ * R1-R5 argument passing registers
+ * R6-R9 callee saved registers
+ * R10 - frame pointer read-only
+ *
+ * At the start of BPF program the register R1 contains a pointer to bpf_context
+ * and has type PTR_TO_CTX.
+ *
+ * Verifier tracks arithmetic operations on pointers in case:
+ *    BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+ *    BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -20),
+ * 1st insn copies R10 (which has FRAME_PTR) type into R1
+ * and 2nd arithmetic instruction is pattern matched to recognize
+ * that it wants to construct a pointer to some element within stack.
+ * So after 2nd insn, the register R1 has type PTR_TO_STACK
+ * (and -20 constant is saved for further stack bounds checking).
+ * Meaning that this reg is a pointer to stack plus known immediate constant.
+ *
+ * Most of the time the registers have SCALAR_VALUE type, which
+ * means the register has some value, but it's not a valid pointer.
+ * (like pointer plus pointer becomes SCALAR_VALUE type)
+ *
+ * When verifier sees load or store instructions the type of base register
+ * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK, PTR_TO_SOCKET. These are
+ * four pointer types recognized by check_mem_access() function.
+ *
+ * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value'
+ * and the range of [ptr, ptr + map's value_size) is accessible.
+ *
+ * registers used to pass values to function calls are checked against
+ * function argument constraints.
+ *
+ * ARG_PTR_TO_MAP_KEY is one of such argument constraints.
+ * It means that the register type passed to this function must be
+ * PTR_TO_STACK and it will be used inside the function as
+ * 'pointer to map element key'
+ *
+ * For example the argument constraints for bpf_map_lookup_elem():
+ *   .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
+ *   .arg1_type = ARG_CONST_MAP_PTR,
+ *   .arg2_type = ARG_PTR_TO_MAP_KEY,
+ *
+ * ret_type says that this function returns 'pointer to map elem value or null'
+ * function expects 1st argument to be a const pointer to 'struct bpf_map' and
+ * 2nd argument should be a pointer to stack, which will be used inside
+ * the helper function as a pointer to map element key.
+ *
+ * On the kernel side the helper function looks like:
+ * u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+ * {
+ *    struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
+ *    void *key = (void *) (unsigned long) r2;
+ *    void *value;
+ *
+ *    here kernel can access 'key' and 'map' pointers safely, knowing that
+ *    [key, key + map->key_size) bytes are valid and were initialized on
+ *    the stack of eBPF program.
+ * }
+ *
+ * Corresponding eBPF program may look like:
+ *    BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),  // after this insn R2 type is FRAME_PTR
+ *    BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), // after this insn R2 type is PTR_TO_STACK
+ *    BPF_LD_MAP_FD(BPF_REG_1, map_fd),      // after this insn R1 type is CONST_PTR_TO_MAP
+ *    BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ * here verifier looks at prototype of map_lookup_elem() and sees:
+ * .arg1_type == ARG_CONST_MAP_PTR and R1->type == CONST_PTR_TO_MAP, which is ok,
+ * Now verifier knows that this map has key of R1->map_ptr->key_size bytes
+ *
+ * Then .arg2_type == ARG_PTR_TO_MAP_KEY and R2->type == PTR_TO_STACK, ok so far,
+ * Now verifier checks that [R2, R2 + map's key_size) are within stack limits
+ * and were initialized prior to this call.
+ * If it's ok, then verifier allows this BPF_CALL insn and looks at
+ * .ret_type which is RET_PTR_TO_MAP_VALUE_OR_NULL, so it sets
+ * R0->type = PTR_TO_MAP_VALUE_OR_NULL which means bpf_map_lookup_elem() function
+ * returns either pointer to map value or NULL.
+ *
+ * When type PTR_TO_MAP_VALUE_OR_NULL passes through 'if (reg != 0) goto +off'
+ * insn, the register holding that pointer in the true branch changes state to
+ * PTR_TO_MAP_VALUE and the same register changes state to CONST_IMM in the false
+ * branch. See check_cond_jmp_op().
+ *
+ * After the call R0 is set to return type of the function and registers R1-R5
+ * are set to NOT_INIT to indicate that they are no longer readable.
+ *
+ * The following reference types represent a potential reference to a kernel
+ * resource which, after first being allocated, must be checked and freed by
+ * the BPF program:
+ * - PTR_TO_SOCKET_OR_NULL, PTR_TO_SOCKET
+ *
+ * When the verifier sees a helper call return a reference type, it allocates a
+ * pointer id for the reference and stores it in the current function state.
+ * Similar to the way that PTR_TO_MAP_VALUE_OR_NULL is converted into
+ * PTR_TO_MAP_VALUE, PTR_TO_SOCKET_OR_NULL becomes PTR_TO_SOCKET when the type
+ * passes through a NULL-check conditional. For the branch wherein the state is
+ * changed to CONST_IMM, the verifier releases the reference.
+ *
+ * For each helper function that allocates a reference, such as
+ * bpf_sk_lookup_tcp(), there is a corresponding release function, such as
+ * bpf_sk_release(). When a reference type passes into the release function,
+ * the verifier also releases the reference. If any unchecked or unreleased
+ * reference remains at the end of the program, the verifier rejects it.
+ */
+
+/* verifier_state + insn_idx are pushed to stack when branch is encountered */
+struct bpf_verifier_stack_elem {
+	/* verifer state is 'st'
+	 * before processing instruction 'insn_idx'
+	 * and after processing instruction 'prev_insn_idx'
+	 */
+	struct bpf_verifier_state st;
+	int insn_idx;
+	int prev_insn_idx;
+	struct bpf_verifier_stack_elem *next;
+	/* length of verifier log at the time this state was pushed on stack */
+	u32 log_pos;
+};
+
+#define BPF_COMPLEXITY_LIMIT_JMP_SEQ	8192
+#define BPF_COMPLEXITY_LIMIT_STATES	64
+
+#define BPF_MAP_KEY_POISON	(1ULL << 63)
+#define BPF_MAP_KEY_SEEN	(1ULL << 62)
+
+#define BPF_MAP_PTR_UNPRIV	1UL
+#define BPF_MAP_PTR_POISON	((void *)((0xeB9FUL << 1) +	\
+					  POISON_POINTER_DELTA))
+#define BPF_MAP_PTR(X)		((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV))
+
+static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx);
+static int release_reference(struct bpf_verifier_env *env, int ref_obj_id);
+
+static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux)
+{
+	return BPF_MAP_PTR(aux->map_ptr_state) == BPF_MAP_PTR_POISON;
+}
+
+static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data *aux)
+{
+	return aux->map_ptr_state & BPF_MAP_PTR_UNPRIV;
+}
+
+static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux,
+			      const struct bpf_map *map, bool unpriv)
+{
+	BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON & BPF_MAP_PTR_UNPRIV);
+	unpriv |= bpf_map_ptr_unpriv(aux);
+	aux->map_ptr_state = (unsigned long)map |
+			     (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL);
+}
+
+static bool bpf_map_key_poisoned(const struct bpf_insn_aux_data *aux)
+{
+	return aux->map_key_state & BPF_MAP_KEY_POISON;
+}
+
+static bool bpf_map_key_unseen(const struct bpf_insn_aux_data *aux)
+{
+	return !(aux->map_key_state & BPF_MAP_KEY_SEEN);
+}
+
+static u64 bpf_map_key_immediate(const struct bpf_insn_aux_data *aux)
+{
+	return aux->map_key_state & ~(BPF_MAP_KEY_SEEN | BPF_MAP_KEY_POISON);
+}
+
+static void bpf_map_key_store(struct bpf_insn_aux_data *aux, u64 state)
+{
+	bool poisoned = bpf_map_key_poisoned(aux);
+
+	aux->map_key_state = state | BPF_MAP_KEY_SEEN |
+			     (poisoned ? BPF_MAP_KEY_POISON : 0ULL);
+}
+
+static bool bpf_pseudo_call(const struct bpf_insn *insn)
+{
+	return insn->code == (BPF_JMP | BPF_CALL) &&
+	       insn->src_reg == BPF_PSEUDO_CALL;
+}
+
+static bool bpf_pseudo_kfunc_call(const struct bpf_insn *insn)
+{
+	return insn->code == (BPF_JMP | BPF_CALL) &&
+	       insn->src_reg == BPF_PSEUDO_KFUNC_CALL;
+}
+
+struct bpf_call_arg_meta {
+	struct bpf_map *map_ptr;
+	bool raw_mode;
+	bool pkt_access;
+	u8 release_regno;
+	int regno;
+	int access_size;
+	int mem_size;
+	u64 msize_max_value;
+	int ref_obj_id;
+	int map_uid;
+	int func_id;
+	struct btf *btf;
+	u32 btf_id;
+	struct btf *ret_btf;
+	u32 ret_btf_id;
+	u32 subprogno;
+	struct bpf_map_value_off_desc *kptr_off_desc;
+	u8 uninit_dynptr_regno;
+};
+
+struct btf *btf_vmlinux;
+
+static DEFINE_MUTEX(bpf_verifier_lock);
+
+static const struct bpf_line_info *
+find_linfo(const struct bpf_verifier_env *env, u32 insn_off)
+{
+	const struct bpf_line_info *linfo;
+	const struct bpf_prog *prog;
+	u32 i, nr_linfo;
+
+	prog = env->prog;
+	nr_linfo = prog->aux->nr_linfo;
+
+	if (!nr_linfo || insn_off >= prog->len)
+		return NULL;
+
+	linfo = prog->aux->linfo;
+	for (i = 1; i < nr_linfo; i++)
+		if (insn_off < linfo[i].insn_off)
+			break;
+
+	return &linfo[i - 1];
+}
+
+void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt,
+		       va_list args)
+{
+	unsigned int n;
+
+	n = vscnprintf(log->kbuf, BPF_VERIFIER_TMP_LOG_SIZE, fmt, args);
+
+	WARN_ONCE(n >= BPF_VERIFIER_TMP_LOG_SIZE - 1,
+		  "verifier log line truncated - local buffer too short\n");
+
+	if (log->level == BPF_LOG_KERNEL) {
+		bool newline = n > 0 && log->kbuf[n - 1] == '\n';
+
+		pr_err("BPF: %s%s", log->kbuf, newline ? "" : "\n");
+		return;
+	}
+
+	n = min(log->len_total - log->len_used - 1, n);
+	log->kbuf[n] = '\0';
+	if (!copy_to_user(log->ubuf + log->len_used, log->kbuf, n + 1))
+		log->len_used += n;
+	else
+		log->ubuf = NULL;
+}
+
+static void bpf_vlog_reset(struct bpf_verifier_log *log, u32 new_pos)
+{
+	char zero = 0;
+
+	if (!bpf_verifier_log_needed(log))
+		return;
+
+	log->len_used = new_pos;
+	if (put_user(zero, log->ubuf + new_pos))
+		log->ubuf = NULL;
+}
+
+/* log_level controls verbosity level of eBPF verifier.
+ * bpf_verifier_log_write() is used to dump the verification trace to the log,
+ * so the user can figure out what's wrong with the program
+ */
+__printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,
+					   const char *fmt, ...)
+{
+	va_list args;
+
+	if (!bpf_verifier_log_needed(&env->log))
+		return;
+
+	va_start(args, fmt);
+	bpf_verifier_vlog(&env->log, fmt, args);
+	va_end(args);
+}
+EXPORT_SYMBOL_GPL(bpf_verifier_log_write);
+
+__printf(2, 3) static void verbose(void *private_data, const char *fmt, ...)
+{
+	struct bpf_verifier_env *env = private_data;
+	va_list args;
+
+	if (!bpf_verifier_log_needed(&env->log))
+		return;
+
+	va_start(args, fmt);
+	bpf_verifier_vlog(&env->log, fmt, args);
+	va_end(args);
+}
+
+__printf(2, 3) void bpf_log(struct bpf_verifier_log *log,
+			    const char *fmt, ...)
+{
+	va_list args;
+
+	if (!bpf_verifier_log_needed(log))
+		return;
+
+	va_start(args, fmt);
+	bpf_verifier_vlog(log, fmt, args);
+	va_end(args);
+}
+EXPORT_SYMBOL_GPL(bpf_log);
+
+static const char *ltrim(const char *s)
+{
+	while (isspace(*s))
+		s++;
+
+	return s;
+}
+
+__printf(3, 4) static void verbose_linfo(struct bpf_verifier_env *env,
+					 u32 insn_off,
+					 const char *prefix_fmt, ...)
+{
+	const struct bpf_line_info *linfo;
+
+	if (!bpf_verifier_log_needed(&env->log))
+		return;
+
+	linfo = find_linfo(env, insn_off);
+	if (!linfo || linfo == env->prev_linfo)
+		return;
+
+	if (prefix_fmt) {
+		va_list args;
+
+		va_start(args, prefix_fmt);
+		bpf_verifier_vlog(&env->log, prefix_fmt, args);
+		va_end(args);
+	}
+
+	verbose(env, "%s\n",
+		ltrim(btf_name_by_offset(env->prog->aux->btf,
+					 linfo->line_off)));
+
+	env->prev_linfo = linfo;
+}
+
+static void verbose_invalid_scalar(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *reg,
+				   struct tnum *range, const char *ctx,
+				   const char *reg_name)
+{
+	char tn_buf[48];
+
+	verbose(env, "At %s the register %s ", ctx, reg_name);
+	if (!tnum_is_unknown(reg->var_off)) {
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env, "has value %s", tn_buf);
+	} else {
+		verbose(env, "has unknown scalar value");
+	}
+	tnum_strn(tn_buf, sizeof(tn_buf), *range);
+	verbose(env, " should have been in %s\n", tn_buf);
+}
+
+static bool type_is_pkt_pointer(enum bpf_reg_type type)
+{
+	type = base_type(type);
+	return type == PTR_TO_PACKET ||
+	       type == PTR_TO_PACKET_META;
+}
+
+static bool type_is_sk_pointer(enum bpf_reg_type type)
+{
+	return type == PTR_TO_SOCKET ||
+		type == PTR_TO_SOCK_COMMON ||
+		type == PTR_TO_TCP_SOCK ||
+		type == PTR_TO_XDP_SOCK;
+}
+
+static bool reg_type_not_null(enum bpf_reg_type type)
+{
+	return type == PTR_TO_SOCKET ||
+		type == PTR_TO_TCP_SOCK ||
+		type == PTR_TO_MAP_VALUE ||
+		type == PTR_TO_MAP_KEY ||
+		type == PTR_TO_SOCK_COMMON;
+}
+
+static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
+{
+	return reg->type == PTR_TO_MAP_VALUE &&
+		map_value_has_spin_lock(reg->map_ptr);
+}
+
+static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type)
+{
+	type = base_type(type);
+	return type == PTR_TO_SOCKET || type == PTR_TO_TCP_SOCK ||
+		type == PTR_TO_MEM || type == PTR_TO_BTF_ID;
+}
+
+static bool type_is_rdonly_mem(u32 type)
+{
+	return type & MEM_RDONLY;
+}
+
+static bool type_may_be_null(u32 type)
+{
+	return type & PTR_MAYBE_NULL;
+}
+
+static bool is_acquire_function(enum bpf_func_id func_id,
+				const struct bpf_map *map)
+{
+	enum bpf_map_type map_type = map ? map->map_type : BPF_MAP_TYPE_UNSPEC;
+
+	if (func_id == BPF_FUNC_sk_lookup_tcp ||
+	    func_id == BPF_FUNC_sk_lookup_udp ||
+	    func_id == BPF_FUNC_skc_lookup_tcp ||
+	    func_id == BPF_FUNC_ringbuf_reserve ||
+	    func_id == BPF_FUNC_kptr_xchg)
+		return true;
+
+	if (func_id == BPF_FUNC_map_lookup_elem &&
+	    (map_type == BPF_MAP_TYPE_SOCKMAP ||
+	     map_type == BPF_MAP_TYPE_SOCKHASH))
+		return true;
+
+	return false;
+}
+
+static bool is_ptr_cast_function(enum bpf_func_id func_id)
+{
+	return func_id == BPF_FUNC_tcp_sock ||
+		func_id == BPF_FUNC_sk_fullsock ||
+		func_id == BPF_FUNC_skc_to_tcp_sock ||
+		func_id == BPF_FUNC_skc_to_tcp6_sock ||
+		func_id == BPF_FUNC_skc_to_udp6_sock ||
+		func_id == BPF_FUNC_skc_to_mptcp_sock ||
+		func_id == BPF_FUNC_skc_to_tcp_timewait_sock ||
+		func_id == BPF_FUNC_skc_to_tcp_request_sock;
+}
+
+static bool is_dynptr_ref_function(enum bpf_func_id func_id)
+{
+	return func_id == BPF_FUNC_dynptr_data;
+}
+
+static bool is_callback_calling_function(enum bpf_func_id func_id)
+{
+	return func_id == BPF_FUNC_for_each_map_elem ||
+	       func_id == BPF_FUNC_timer_set_callback ||
+	       func_id == BPF_FUNC_find_vma ||
+	       func_id == BPF_FUNC_loop ||
+	       func_id == BPF_FUNC_user_ringbuf_drain;
+}
+
+static bool helper_multiple_ref_obj_use(enum bpf_func_id func_id,
+					const struct bpf_map *map)
+{
+	int ref_obj_uses = 0;
+
+	if (is_ptr_cast_function(func_id))
+		ref_obj_uses++;
+	if (is_acquire_function(func_id, map))
+		ref_obj_uses++;
+	if (is_dynptr_ref_function(func_id))
+		ref_obj_uses++;
+
+	return ref_obj_uses > 1;
+}
+
+static bool is_cmpxchg_insn(const struct bpf_insn *insn)
+{
+	return BPF_CLASS(insn->code) == BPF_STX &&
+	       BPF_MODE(insn->code) == BPF_ATOMIC &&
+	       insn->imm == BPF_CMPXCHG;
+}
+
+/* string representation of 'enum bpf_reg_type'
+ *
+ * Note that reg_type_str() can not appear more than once in a single verbose()
+ * statement.
+ */
+static const char *reg_type_str(struct bpf_verifier_env *env,
+				enum bpf_reg_type type)
+{
+	char postfix[16] = {0}, prefix[32] = {0};
+	static const char * const str[] = {
+		[NOT_INIT]		= "?",
+		[SCALAR_VALUE]		= "scalar",
+		[PTR_TO_CTX]		= "ctx",
+		[CONST_PTR_TO_MAP]	= "map_ptr",
+		[PTR_TO_MAP_VALUE]	= "map_value",
+		[PTR_TO_STACK]		= "fp",
+		[PTR_TO_PACKET]		= "pkt",
+		[PTR_TO_PACKET_META]	= "pkt_meta",
+		[PTR_TO_PACKET_END]	= "pkt_end",
+		[PTR_TO_FLOW_KEYS]	= "flow_keys",
+		[PTR_TO_SOCKET]		= "sock",
+		[PTR_TO_SOCK_COMMON]	= "sock_common",
+		[PTR_TO_TCP_SOCK]	= "tcp_sock",
+		[PTR_TO_TP_BUFFER]	= "tp_buffer",
+		[PTR_TO_XDP_SOCK]	= "xdp_sock",
+		[PTR_TO_BTF_ID]		= "ptr_",
+		[PTR_TO_MEM]		= "mem",
+		[PTR_TO_BUF]		= "buf",
+		[PTR_TO_FUNC]		= "func",
+		[PTR_TO_MAP_KEY]	= "map_key",
+		[PTR_TO_DYNPTR]		= "dynptr_ptr",
+	};
+
+	if (type & PTR_MAYBE_NULL) {
+		if (base_type(type) == PTR_TO_BTF_ID)
+			strncpy(postfix, "or_null_", 16);
+		else
+			strncpy(postfix, "_or_null", 16);
+	}
+
+	if (type & MEM_RDONLY)
+		strncpy(prefix, "rdonly_", 32);
+	if (type & MEM_ALLOC)
+		strncpy(prefix, "alloc_", 32);
+	if (type & MEM_USER)
+		strncpy(prefix, "user_", 32);
+	if (type & MEM_PERCPU)
+		strncpy(prefix, "percpu_", 32);
+	if (type & PTR_UNTRUSTED)
+		strncpy(prefix, "untrusted_", 32);
+
+	snprintf(env->type_str_buf, TYPE_STR_BUF_LEN, "%s%s%s",
+		 prefix, str[base_type(type)], postfix);
+	return env->type_str_buf;
+}
+
+static char slot_type_char[] = {
+	[STACK_INVALID]	= '?',
+	[STACK_SPILL]	= 'r',
+	[STACK_MISC]	= 'm',
+	[STACK_ZERO]	= '0',
+	[STACK_DYNPTR]	= 'd',
+};
+
+static void print_liveness(struct bpf_verifier_env *env,
+			   enum bpf_reg_liveness live)
+{
+	if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN | REG_LIVE_DONE))
+	    verbose(env, "_");
+	if (live & REG_LIVE_READ)
+		verbose(env, "r");
+	if (live & REG_LIVE_WRITTEN)
+		verbose(env, "w");
+	if (live & REG_LIVE_DONE)
+		verbose(env, "D");
+}
+
+static int get_spi(s32 off)
+{
+	return (-off - 1) / BPF_REG_SIZE;
+}
+
+static bool is_spi_bounds_valid(struct bpf_func_state *state, int spi, int nr_slots)
+{
+	int allocated_slots = state->allocated_stack / BPF_REG_SIZE;
+
+	/* We need to check that slots between [spi - nr_slots + 1, spi] are
+	 * within [0, allocated_stack).
+	 *
+	 * Please note that the spi grows downwards. For example, a dynptr
+	 * takes the size of two stack slots; the first slot will be at
+	 * spi and the second slot will be at spi - 1.
+	 */
+	return spi - nr_slots + 1 >= 0 && spi < allocated_slots;
+}
+
+static struct bpf_func_state *func(struct bpf_verifier_env *env,
+				   const struct bpf_reg_state *reg)
+{
+	struct bpf_verifier_state *cur = env->cur_state;
+
+	return cur->frame[reg->frameno];
+}
+
+static const char *kernel_type_name(const struct btf* btf, u32 id)
+{
+	return btf_name_by_offset(btf, btf_type_by_id(btf, id)->name_off);
+}
+
+static void mark_reg_scratched(struct bpf_verifier_env *env, u32 regno)
+{
+	env->scratched_regs |= 1U << regno;
+}
+
+static void mark_stack_slot_scratched(struct bpf_verifier_env *env, u32 spi)
+{
+	env->scratched_stack_slots |= 1ULL << spi;
+}
+
+static bool reg_scratched(const struct bpf_verifier_env *env, u32 regno)
+{
+	return (env->scratched_regs >> regno) & 1;
+}
+
+static bool stack_slot_scratched(const struct bpf_verifier_env *env, u64 regno)
+{
+	return (env->scratched_stack_slots >> regno) & 1;
+}
+
+static bool verifier_state_scratched(const struct bpf_verifier_env *env)
+{
+	return env->scratched_regs || env->scratched_stack_slots;
+}
+
+static void mark_verifier_state_clean(struct bpf_verifier_env *env)
+{
+	env->scratched_regs = 0U;
+	env->scratched_stack_slots = 0ULL;
+}
+
+/* Used for printing the entire verifier state. */
+static void mark_verifier_state_scratched(struct bpf_verifier_env *env)
+{
+	env->scratched_regs = ~0U;
+	env->scratched_stack_slots = ~0ULL;
+}
+
+static enum bpf_dynptr_type arg_to_dynptr_type(enum bpf_arg_type arg_type)
+{
+	switch (arg_type & DYNPTR_TYPE_FLAG_MASK) {
+	case DYNPTR_TYPE_LOCAL:
+		return BPF_DYNPTR_TYPE_LOCAL;
+	case DYNPTR_TYPE_RINGBUF:
+		return BPF_DYNPTR_TYPE_RINGBUF;
+	default:
+		return BPF_DYNPTR_TYPE_INVALID;
+	}
+}
+
+static bool dynptr_type_refcounted(enum bpf_dynptr_type type)
+{
+	return type == BPF_DYNPTR_TYPE_RINGBUF;
+}
+
+static int mark_stack_slots_dynptr(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+				   enum bpf_arg_type arg_type, int insn_idx)
+{
+	struct bpf_func_state *state = func(env, reg);
+	enum bpf_dynptr_type type;
+	int spi, i, id;
+
+	spi = get_spi(reg->off);
+
+	if (!is_spi_bounds_valid(state, spi, BPF_DYNPTR_NR_SLOTS))
+		return -EINVAL;
+
+	for (i = 0; i < BPF_REG_SIZE; i++) {
+		state->stack[spi].slot_type[i] = STACK_DYNPTR;
+		state->stack[spi - 1].slot_type[i] = STACK_DYNPTR;
+	}
+
+	type = arg_to_dynptr_type(arg_type);
+	if (type == BPF_DYNPTR_TYPE_INVALID)
+		return -EINVAL;
+
+	state->stack[spi].spilled_ptr.dynptr.first_slot = true;
+	state->stack[spi].spilled_ptr.dynptr.type = type;
+	state->stack[spi - 1].spilled_ptr.dynptr.type = type;
+
+	if (dynptr_type_refcounted(type)) {
+		/* The id is used to track proper releasing */
+		id = acquire_reference_state(env, insn_idx);
+		if (id < 0)
+			return id;
+
+		state->stack[spi].spilled_ptr.id = id;
+		state->stack[spi - 1].spilled_ptr.id = id;
+	}
+
+	return 0;
+}
+
+static int unmark_stack_slots_dynptr(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi, i;
+
+	spi = get_spi(reg->off);
+
+	if (!is_spi_bounds_valid(state, spi, BPF_DYNPTR_NR_SLOTS))
+		return -EINVAL;
+
+	for (i = 0; i < BPF_REG_SIZE; i++) {
+		state->stack[spi].slot_type[i] = STACK_INVALID;
+		state->stack[spi - 1].slot_type[i] = STACK_INVALID;
+	}
+
+	/* Invalidate any slices associated with this dynptr */
+	if (dynptr_type_refcounted(state->stack[spi].spilled_ptr.dynptr.type)) {
+		release_reference(env, state->stack[spi].spilled_ptr.id);
+		state->stack[spi].spilled_ptr.id = 0;
+		state->stack[spi - 1].spilled_ptr.id = 0;
+	}
+
+	state->stack[spi].spilled_ptr.dynptr.first_slot = false;
+	state->stack[spi].spilled_ptr.dynptr.type = 0;
+	state->stack[spi - 1].spilled_ptr.dynptr.type = 0;
+
+	return 0;
+}
+
+static bool is_dynptr_reg_valid_uninit(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi = get_spi(reg->off);
+	int i;
+
+	if (!is_spi_bounds_valid(state, spi, BPF_DYNPTR_NR_SLOTS))
+		return true;
+
+	for (i = 0; i < BPF_REG_SIZE; i++) {
+		if (state->stack[spi].slot_type[i] == STACK_DYNPTR ||
+		    state->stack[spi - 1].slot_type[i] == STACK_DYNPTR)
+			return false;
+	}
+
+	return true;
+}
+
+bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env,
+			      struct bpf_reg_state *reg)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi = get_spi(reg->off);
+	int i;
+
+	if (!is_spi_bounds_valid(state, spi, BPF_DYNPTR_NR_SLOTS) ||
+	    !state->stack[spi].spilled_ptr.dynptr.first_slot)
+		return false;
+
+	for (i = 0; i < BPF_REG_SIZE; i++) {
+		if (state->stack[spi].slot_type[i] != STACK_DYNPTR ||
+		    state->stack[spi - 1].slot_type[i] != STACK_DYNPTR)
+			return false;
+	}
+
+	return true;
+}
+
+bool is_dynptr_type_expected(struct bpf_verifier_env *env,
+			     struct bpf_reg_state *reg,
+			     enum bpf_arg_type arg_type)
+{
+	struct bpf_func_state *state = func(env, reg);
+	enum bpf_dynptr_type dynptr_type;
+	int spi = get_spi(reg->off);
+
+	/* ARG_PTR_TO_DYNPTR takes any type of dynptr */
+	if (arg_type == ARG_PTR_TO_DYNPTR)
+		return true;
+
+	dynptr_type = arg_to_dynptr_type(arg_type);
+
+	return state->stack[spi].spilled_ptr.dynptr.type == dynptr_type;
+}
+
+/* The reg state of a pointer or a bounded scalar was saved when
+ * it was spilled to the stack.
+ */
+static bool is_spilled_reg(const struct bpf_stack_state *stack)
+{
+	return stack->slot_type[BPF_REG_SIZE - 1] == STACK_SPILL;
+}
+
+static void scrub_spilled_slot(u8 *stype)
+{
+	if (*stype != STACK_INVALID)
+		*stype = STACK_MISC;
+}
+
+static void print_verifier_state(struct bpf_verifier_env *env,
+				 const struct bpf_func_state *state,
+				 bool print_all)
+{
+	const struct bpf_reg_state *reg;
+	enum bpf_reg_type t;
+	int i;
+
+	if (state->frameno)
+		verbose(env, " frame%d:", state->frameno);
+	for (i = 0; i < MAX_BPF_REG; i++) {
+		reg = &state->regs[i];
+		t = reg->type;
+		if (t == NOT_INIT)
+			continue;
+		if (!print_all && !reg_scratched(env, i))
+			continue;
+		verbose(env, " R%d", i);
+		print_liveness(env, reg->live);
+		verbose(env, "=");
+		if (t == SCALAR_VALUE && reg->precise)
+			verbose(env, "P");
+		if ((t == SCALAR_VALUE || t == PTR_TO_STACK) &&
+		    tnum_is_const(reg->var_off)) {
+			/* reg->off should be 0 for SCALAR_VALUE */
+			verbose(env, "%s", t == SCALAR_VALUE ? "" : reg_type_str(env, t));
+			verbose(env, "%lld", reg->var_off.value + reg->off);
+		} else {
+			const char *sep = "";
+
+			verbose(env, "%s", reg_type_str(env, t));
+			if (base_type(t) == PTR_TO_BTF_ID)
+				verbose(env, "%s", kernel_type_name(reg->btf, reg->btf_id));
+			verbose(env, "(");
+/*
+ * _a stands for append, was shortened to avoid multiline statements below.
+ * This macro is used to output a comma separated list of attributes.
+ */
+#define verbose_a(fmt, ...) ({ verbose(env, "%s" fmt, sep, __VA_ARGS__); sep = ","; })
+
+			if (reg->id)
+				verbose_a("id=%d", reg->id);
+			if (reg_type_may_be_refcounted_or_null(t) && reg->ref_obj_id)
+				verbose_a("ref_obj_id=%d", reg->ref_obj_id);
+			if (t != SCALAR_VALUE)
+				verbose_a("off=%d", reg->off);
+			if (type_is_pkt_pointer(t))
+				verbose_a("r=%d", reg->range);
+			else if (base_type(t) == CONST_PTR_TO_MAP ||
+				 base_type(t) == PTR_TO_MAP_KEY ||
+				 base_type(t) == PTR_TO_MAP_VALUE)
+				verbose_a("ks=%d,vs=%d",
+					  reg->map_ptr->key_size,
+					  reg->map_ptr->value_size);
+			if (tnum_is_const(reg->var_off)) {
+				/* Typically an immediate SCALAR_VALUE, but
+				 * could be a pointer whose offset is too big
+				 * for reg->off
+				 */
+				verbose_a("imm=%llx", reg->var_off.value);
+			} else {
+				if (reg->smin_value != reg->umin_value &&
+				    reg->smin_value != S64_MIN)
+					verbose_a("smin=%lld", (long long)reg->smin_value);
+				if (reg->smax_value != reg->umax_value &&
+				    reg->smax_value != S64_MAX)
+					verbose_a("smax=%lld", (long long)reg->smax_value);
+				if (reg->umin_value != 0)
+					verbose_a("umin=%llu", (unsigned long long)reg->umin_value);
+				if (reg->umax_value != U64_MAX)
+					verbose_a("umax=%llu", (unsigned long long)reg->umax_value);
+				if (!tnum_is_unknown(reg->var_off)) {
+					char tn_buf[48];
+
+					tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+					verbose_a("var_off=%s", tn_buf);
+				}
+				if (reg->s32_min_value != reg->smin_value &&
+				    reg->s32_min_value != S32_MIN)
+					verbose_a("s32_min=%d", (int)(reg->s32_min_value));
+				if (reg->s32_max_value != reg->smax_value &&
+				    reg->s32_max_value != S32_MAX)
+					verbose_a("s32_max=%d", (int)(reg->s32_max_value));
+				if (reg->u32_min_value != reg->umin_value &&
+				    reg->u32_min_value != U32_MIN)
+					verbose_a("u32_min=%d", (int)(reg->u32_min_value));
+				if (reg->u32_max_value != reg->umax_value &&
+				    reg->u32_max_value != U32_MAX)
+					verbose_a("u32_max=%d", (int)(reg->u32_max_value));
+			}
+#undef verbose_a
+
+			verbose(env, ")");
+		}
+	}
+	for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+		char types_buf[BPF_REG_SIZE + 1];
+		bool valid = false;
+		int j;
+
+		for (j = 0; j < BPF_REG_SIZE; j++) {
+			if (state->stack[i].slot_type[j] != STACK_INVALID)
+				valid = true;
+			types_buf[j] = slot_type_char[
+					state->stack[i].slot_type[j]];
+		}
+		types_buf[BPF_REG_SIZE] = 0;
+		if (!valid)
+			continue;
+		if (!print_all && !stack_slot_scratched(env, i))
+			continue;
+		verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
+		print_liveness(env, state->stack[i].spilled_ptr.live);
+		if (is_spilled_reg(&state->stack[i])) {
+			reg = &state->stack[i].spilled_ptr;
+			t = reg->type;
+			verbose(env, "=%s", t == SCALAR_VALUE ? "" : reg_type_str(env, t));
+			if (t == SCALAR_VALUE && reg->precise)
+				verbose(env, "P");
+			if (t == SCALAR_VALUE && tnum_is_const(reg->var_off))
+				verbose(env, "%lld", reg->var_off.value + reg->off);
+		} else {
+			verbose(env, "=%s", types_buf);
+		}
+	}
+	if (state->acquired_refs && state->refs[0].id) {
+		verbose(env, " refs=%d", state->refs[0].id);
+		for (i = 1; i < state->acquired_refs; i++)
+			if (state->refs[i].id)
+				verbose(env, ",%d", state->refs[i].id);
+	}
+	if (state->in_callback_fn)
+		verbose(env, " cb");
+	if (state->in_async_callback_fn)
+		verbose(env, " async_cb");
+	verbose(env, "\n");
+	if (!print_all)
+		mark_verifier_state_clean(env);
+}
+
+static inline u32 vlog_alignment(u32 pos)
+{
+	return round_up(max(pos + BPF_LOG_MIN_ALIGNMENT / 2, BPF_LOG_ALIGNMENT),
+			BPF_LOG_MIN_ALIGNMENT) - pos - 1;
+}
+
+static void print_insn_state(struct bpf_verifier_env *env,
+			     const struct bpf_func_state *state)
+{
+	if (env->prev_log_len && env->prev_log_len == env->log.len_used) {
+		/* remove new line character */
+		bpf_vlog_reset(&env->log, env->prev_log_len - 1);
+		verbose(env, "%*c;", vlog_alignment(env->prev_insn_print_len), ' ');
+	} else {
+		verbose(env, "%d:", env->insn_idx);
+	}
+	print_verifier_state(env, state, false);
+}
+
+/* copy array src of length n * size bytes to dst. dst is reallocated if it's too
+ * small to hold src. This is different from krealloc since we don't want to preserve
+ * the contents of dst.
+ *
+ * Leaves dst untouched if src is NULL or length is zero. Returns NULL if memory could
+ * not be allocated.
+ */
+static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t flags)
+{
+	size_t alloc_bytes;
+	void *orig = dst;
+	size_t bytes;
+
+	if (ZERO_OR_NULL_PTR(src))
+		goto out;
+
+	if (unlikely(check_mul_overflow(n, size, &bytes)))
+		return NULL;
+
+	alloc_bytes = max(ksize(orig), kmalloc_size_roundup(bytes));
+	dst = krealloc(orig, alloc_bytes, flags);
+	if (!dst) {
+		kfree(orig);
+		return NULL;
+	}
+
+	memcpy(dst, src, bytes);
+out:
+	return dst ? dst : ZERO_SIZE_PTR;
+}
+
+/* resize an array from old_n items to new_n items. the array is reallocated if it's too
+ * small to hold new_n items. new items are zeroed out if the array grows.
+ *
+ * Contrary to krealloc_array, does not free arr if new_n is zero.
+ */
+static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size)
+{
+	size_t alloc_size;
+	void *new_arr;
+
+	if (!new_n || old_n == new_n)
+		goto out;
+
+	alloc_size = kmalloc_size_roundup(size_mul(new_n, size));
+	new_arr = krealloc(arr, alloc_size, GFP_KERNEL);
+	if (!new_arr) {
+		kfree(arr);
+		return NULL;
+	}
+	arr = new_arr;
+
+	if (new_n > old_n)
+		memset(arr + old_n * size, 0, (new_n - old_n) * size);
+
+out:
+	return arr ? arr : ZERO_SIZE_PTR;
+}
+
+static int copy_reference_state(struct bpf_func_state *dst, const struct bpf_func_state *src)
+{
+	dst->refs = copy_array(dst->refs, src->refs, src->acquired_refs,
+			       sizeof(struct bpf_reference_state), GFP_KERNEL);
+	if (!dst->refs)
+		return -ENOMEM;
+
+	dst->acquired_refs = src->acquired_refs;
+	return 0;
+}
+
+static int copy_stack_state(struct bpf_func_state *dst, const struct bpf_func_state *src)
+{
+	size_t n = src->allocated_stack / BPF_REG_SIZE;
+
+	dst->stack = copy_array(dst->stack, src->stack, n, sizeof(struct bpf_stack_state),
+				GFP_KERNEL);
+	if (!dst->stack)
+		return -ENOMEM;
+
+	dst->allocated_stack = src->allocated_stack;
+	return 0;
+}
+
+static int resize_reference_state(struct bpf_func_state *state, size_t n)
+{
+	state->refs = realloc_array(state->refs, state->acquired_refs, n,
+				    sizeof(struct bpf_reference_state));
+	if (!state->refs)
+		return -ENOMEM;
+
+	state->acquired_refs = n;
+	return 0;
+}
+
+static int grow_stack_state(struct bpf_func_state *state, int size)
+{
+	size_t old_n = state->allocated_stack / BPF_REG_SIZE, n = size / BPF_REG_SIZE;
+
+	if (old_n >= n)
+		return 0;
+
+	state->stack = realloc_array(state->stack, old_n, n, sizeof(struct bpf_stack_state));
+	if (!state->stack)
+		return -ENOMEM;
+
+	state->allocated_stack = size;
+	return 0;
+}
+
+/* Acquire a pointer id from the env and update the state->refs to include
+ * this new pointer reference.
+ * On success, returns a valid pointer id to associate with the register
+ * On failure, returns a negative errno.
+ */
+static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx)
+{
+	struct bpf_func_state *state = cur_func(env);
+	int new_ofs = state->acquired_refs;
+	int id, err;
+
+	err = resize_reference_state(state, state->acquired_refs + 1);
+	if (err)
+		return err;
+	id = ++env->id_gen;
+	state->refs[new_ofs].id = id;
+	state->refs[new_ofs].insn_idx = insn_idx;
+	state->refs[new_ofs].callback_ref = state->in_callback_fn ? state->frameno : 0;
+
+	return id;
+}
+
+/* release function corresponding to acquire_reference_state(). Idempotent. */
+static int release_reference_state(struct bpf_func_state *state, int ptr_id)
+{
+	int i, last_idx;
+
+	last_idx = state->acquired_refs - 1;
+	for (i = 0; i < state->acquired_refs; i++) {
+		if (state->refs[i].id == ptr_id) {
+			/* Cannot release caller references in callbacks */
+			if (state->in_callback_fn && state->refs[i].callback_ref != state->frameno)
+				return -EINVAL;
+			if (last_idx && i != last_idx)
+				memcpy(&state->refs[i], &state->refs[last_idx],
+				       sizeof(*state->refs));
+			memset(&state->refs[last_idx], 0, sizeof(*state->refs));
+			state->acquired_refs--;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static void free_func_state(struct bpf_func_state *state)
+{
+	if (!state)
+		return;
+	kfree(state->refs);
+	kfree(state->stack);
+	kfree(state);
+}
+
+static void clear_jmp_history(struct bpf_verifier_state *state)
+{
+	kfree(state->jmp_history);
+	state->jmp_history = NULL;
+	state->jmp_history_cnt = 0;
+}
+
+static void free_verifier_state(struct bpf_verifier_state *state,
+				bool free_self)
+{
+	int i;
+
+	for (i = 0; i <= state->curframe; i++) {
+		free_func_state(state->frame[i]);
+		state->frame[i] = NULL;
+	}
+	clear_jmp_history(state);
+	if (free_self)
+		kfree(state);
+}
+
+/* copy verifier state from src to dst growing dst stack space
+ * when necessary to accommodate larger src stack
+ */
+static int copy_func_state(struct bpf_func_state *dst,
+			   const struct bpf_func_state *src)
+{
+	int err;
+
+	memcpy(dst, src, offsetof(struct bpf_func_state, acquired_refs));
+	err = copy_reference_state(dst, src);
+	if (err)
+		return err;
+	return copy_stack_state(dst, src);
+}
+
+static int copy_verifier_state(struct bpf_verifier_state *dst_state,
+			       const struct bpf_verifier_state *src)
+{
+	struct bpf_func_state *dst;
+	int i, err;
+
+	dst_state->jmp_history = copy_array(dst_state->jmp_history, src->jmp_history,
+					    src->jmp_history_cnt, sizeof(struct bpf_idx_pair),
+					    GFP_USER);
+	if (!dst_state->jmp_history)
+		return -ENOMEM;
+	dst_state->jmp_history_cnt = src->jmp_history_cnt;
+
+	/* if dst has more stack frames then src frame, free them */
+	for (i = src->curframe + 1; i <= dst_state->curframe; i++) {
+		free_func_state(dst_state->frame[i]);
+		dst_state->frame[i] = NULL;
+	}
+	dst_state->speculative = src->speculative;
+	dst_state->curframe = src->curframe;
+	dst_state->active_spin_lock = src->active_spin_lock;
+	dst_state->branches = src->branches;
+	dst_state->parent = src->parent;
+	dst_state->first_insn_idx = src->first_insn_idx;
+	dst_state->last_insn_idx = src->last_insn_idx;
+	for (i = 0; i <= src->curframe; i++) {
+		dst = dst_state->frame[i];
+		if (!dst) {
+			dst = kzalloc(sizeof(*dst), GFP_KERNEL);
+			if (!dst)
+				return -ENOMEM;
+			dst_state->frame[i] = dst;
+		}
+		err = copy_func_state(dst, src->frame[i]);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
+{
+	while (st) {
+		u32 br = --st->branches;
+
+		/* WARN_ON(br > 1) technically makes sense here,
+		 * but see comment in push_stack(), hence:
+		 */
+		WARN_ONCE((int)br < 0,
+			  "BUG update_branch_counts:branches_to_explore=%d\n",
+			  br);
+		if (br)
+			break;
+		st = st->parent;
+	}
+}
+
+static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx,
+		     int *insn_idx, bool pop_log)
+{
+	struct bpf_verifier_state *cur = env->cur_state;
+	struct bpf_verifier_stack_elem *elem, *head = env->head;
+	int err;
+
+	if (env->head == NULL)
+		return -ENOENT;
+
+	if (cur) {
+		err = copy_verifier_state(cur, &head->st);
+		if (err)
+			return err;
+	}
+	if (pop_log)
+		bpf_vlog_reset(&env->log, head->log_pos);
+	if (insn_idx)
+		*insn_idx = head->insn_idx;
+	if (prev_insn_idx)
+		*prev_insn_idx = head->prev_insn_idx;
+	elem = head->next;
+	free_verifier_state(&head->st, false);
+	kfree(head);
+	env->head = elem;
+	env->stack_size--;
+	return 0;
+}
+
+static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env,
+					     int insn_idx, int prev_insn_idx,
+					     bool speculative)
+{
+	struct bpf_verifier_state *cur = env->cur_state;
+	struct bpf_verifier_stack_elem *elem;
+	int err;
+
+	elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL);
+	if (!elem)
+		goto err;
+
+	elem->insn_idx = insn_idx;
+	elem->prev_insn_idx = prev_insn_idx;
+	elem->next = env->head;
+	elem->log_pos = env->log.len_used;
+	env->head = elem;
+	env->stack_size++;
+	err = copy_verifier_state(&elem->st, cur);
+	if (err)
+		goto err;
+	elem->st.speculative |= speculative;
+	if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) {
+		verbose(env, "The sequence of %d jumps is too complex.\n",
+			env->stack_size);
+		goto err;
+	}
+	if (elem->st.parent) {
+		++elem->st.parent->branches;
+		/* WARN_ON(branches > 2) technically makes sense here,
+		 * but
+		 * 1. speculative states will bump 'branches' for non-branch
+		 * instructions
+		 * 2. is_state_visited() heuristics may decide not to create
+		 * a new state for a sequence of branches and all such current
+		 * and cloned states will be pointing to a single parent state
+		 * which might have large 'branches' count.
+		 */
+	}
+	return &elem->st;
+err:
+	free_verifier_state(env->cur_state, true);
+	env->cur_state = NULL;
+	/* pop all elements and return */
+	while (!pop_stack(env, NULL, NULL, false));
+	return NULL;
+}
+
+#define CALLER_SAVED_REGS 6
+static const int caller_saved[CALLER_SAVED_REGS] = {
+	BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5
+};
+
+static void __mark_reg_not_init(const struct bpf_verifier_env *env,
+				struct bpf_reg_state *reg);
+
+/* This helper doesn't clear reg->id */
+static void ___mark_reg_known(struct bpf_reg_state *reg, u64 imm)
+{
+	reg->var_off = tnum_const(imm);
+	reg->smin_value = (s64)imm;
+	reg->smax_value = (s64)imm;
+	reg->umin_value = imm;
+	reg->umax_value = imm;
+
+	reg->s32_min_value = (s32)imm;
+	reg->s32_max_value = (s32)imm;
+	reg->u32_min_value = (u32)imm;
+	reg->u32_max_value = (u32)imm;
+}
+
+/* Mark the unknown part of a register (variable offset or scalar value) as
+ * known to have the value @imm.
+ */
+static void __mark_reg_known(struct bpf_reg_state *reg, u64 imm)
+{
+	/* Clear id, off, and union(map_ptr, range) */
+	memset(((u8 *)reg) + sizeof(reg->type), 0,
+	       offsetof(struct bpf_reg_state, var_off) - sizeof(reg->type));
+	___mark_reg_known(reg, imm);
+}
+
+static void __mark_reg32_known(struct bpf_reg_state *reg, u64 imm)
+{
+	reg->var_off = tnum_const_subreg(reg->var_off, imm);
+	reg->s32_min_value = (s32)imm;
+	reg->s32_max_value = (s32)imm;
+	reg->u32_min_value = (u32)imm;
+	reg->u32_max_value = (u32)imm;
+}
+
+/* Mark the 'variable offset' part of a register as zero.  This should be
+ * used only on registers holding a pointer type.
+ */
+static void __mark_reg_known_zero(struct bpf_reg_state *reg)
+{
+	__mark_reg_known(reg, 0);
+}
+
+static void __mark_reg_const_zero(struct bpf_reg_state *reg)
+{
+	__mark_reg_known(reg, 0);
+	reg->type = SCALAR_VALUE;
+}
+
+static void mark_reg_known_zero(struct bpf_verifier_env *env,
+				struct bpf_reg_state *regs, u32 regno)
+{
+	if (WARN_ON(regno >= MAX_BPF_REG)) {
+		verbose(env, "mark_reg_known_zero(regs, %u)\n", regno);
+		/* Something bad happened, let's kill all regs */
+		for (regno = 0; regno < MAX_BPF_REG; regno++)
+			__mark_reg_not_init(env, regs + regno);
+		return;
+	}
+	__mark_reg_known_zero(regs + regno);
+}
+
+static void mark_ptr_not_null_reg(struct bpf_reg_state *reg)
+{
+	if (base_type(reg->type) == PTR_TO_MAP_VALUE) {
+		const struct bpf_map *map = reg->map_ptr;
+
+		if (map->inner_map_meta) {
+			reg->type = CONST_PTR_TO_MAP;
+			reg->map_ptr = map->inner_map_meta;
+			/* transfer reg's id which is unique for every map_lookup_elem
+			 * as UID of the inner map.
+			 */
+			if (map_value_has_timer(map->inner_map_meta))
+				reg->map_uid = reg->id;
+		} else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
+			reg->type = PTR_TO_XDP_SOCK;
+		} else if (map->map_type == BPF_MAP_TYPE_SOCKMAP ||
+			   map->map_type == BPF_MAP_TYPE_SOCKHASH) {
+			reg->type = PTR_TO_SOCKET;
+		} else {
+			reg->type = PTR_TO_MAP_VALUE;
+		}
+		return;
+	}
+
+	reg->type &= ~PTR_MAYBE_NULL;
+}
+
+static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg)
+{
+	return type_is_pkt_pointer(reg->type);
+}
+
+static bool reg_is_pkt_pointer_any(const struct bpf_reg_state *reg)
+{
+	return reg_is_pkt_pointer(reg) ||
+	       reg->type == PTR_TO_PACKET_END;
+}
+
+/* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */
+static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg,
+				    enum bpf_reg_type which)
+{
+	/* The register can already have a range from prior markings.
+	 * This is fine as long as it hasn't been advanced from its
+	 * origin.
+	 */
+	return reg->type == which &&
+	       reg->id == 0 &&
+	       reg->off == 0 &&
+	       tnum_equals_const(reg->var_off, 0);
+}
+
+/* Reset the min/max bounds of a register */
+static void __mark_reg_unbounded(struct bpf_reg_state *reg)
+{
+	reg->smin_value = S64_MIN;
+	reg->smax_value = S64_MAX;
+	reg->umin_value = 0;
+	reg->umax_value = U64_MAX;
+
+	reg->s32_min_value = S32_MIN;
+	reg->s32_max_value = S32_MAX;
+	reg->u32_min_value = 0;
+	reg->u32_max_value = U32_MAX;
+}
+
+static void __mark_reg64_unbounded(struct bpf_reg_state *reg)
+{
+	reg->smin_value = S64_MIN;
+	reg->smax_value = S64_MAX;
+	reg->umin_value = 0;
+	reg->umax_value = U64_MAX;
+}
+
+static void __mark_reg32_unbounded(struct bpf_reg_state *reg)
+{
+	reg->s32_min_value = S32_MIN;
+	reg->s32_max_value = S32_MAX;
+	reg->u32_min_value = 0;
+	reg->u32_max_value = U32_MAX;
+}
+
+static void __update_reg32_bounds(struct bpf_reg_state *reg)
+{
+	struct tnum var32_off = tnum_subreg(reg->var_off);
+
+	/* min signed is max(sign bit) | min(other bits) */
+	reg->s32_min_value = max_t(s32, reg->s32_min_value,
+			var32_off.value | (var32_off.mask & S32_MIN));
+	/* max signed is min(sign bit) | max(other bits) */
+	reg->s32_max_value = min_t(s32, reg->s32_max_value,
+			var32_off.value | (var32_off.mask & S32_MAX));
+	reg->u32_min_value = max_t(u32, reg->u32_min_value, (u32)var32_off.value);
+	reg->u32_max_value = min(reg->u32_max_value,
+				 (u32)(var32_off.value | var32_off.mask));
+}
+
+static void __update_reg64_bounds(struct bpf_reg_state *reg)
+{
+	/* min signed is max(sign bit) | min(other bits) */
+	reg->smin_value = max_t(s64, reg->smin_value,
+				reg->var_off.value | (reg->var_off.mask & S64_MIN));
+	/* max signed is min(sign bit) | max(other bits) */
+	reg->smax_value = min_t(s64, reg->smax_value,
+				reg->var_off.value | (reg->var_off.mask & S64_MAX));
+	reg->umin_value = max(reg->umin_value, reg->var_off.value);
+	reg->umax_value = min(reg->umax_value,
+			      reg->var_off.value | reg->var_off.mask);
+}
+
+static void __update_reg_bounds(struct bpf_reg_state *reg)
+{
+	__update_reg32_bounds(reg);
+	__update_reg64_bounds(reg);
+}
+
+/* Uses signed min/max values to inform unsigned, and vice-versa */
+static void __reg32_deduce_bounds(struct bpf_reg_state *reg)
+{
+	/* Learn sign from signed bounds.
+	 * If we cannot cross the sign boundary, then signed and unsigned bounds
+	 * are the same, so combine.  This works even in the negative case, e.g.
+	 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
+	 */
+	if (reg->s32_min_value >= 0 || reg->s32_max_value < 0) {
+		reg->s32_min_value = reg->u32_min_value =
+			max_t(u32, reg->s32_min_value, reg->u32_min_value);
+		reg->s32_max_value = reg->u32_max_value =
+			min_t(u32, reg->s32_max_value, reg->u32_max_value);
+		return;
+	}
+	/* Learn sign from unsigned bounds.  Signed bounds cross the sign
+	 * boundary, so we must be careful.
+	 */
+	if ((s32)reg->u32_max_value >= 0) {
+		/* Positive.  We can't learn anything from the smin, but smax
+		 * is positive, hence safe.
+		 */
+		reg->s32_min_value = reg->u32_min_value;
+		reg->s32_max_value = reg->u32_max_value =
+			min_t(u32, reg->s32_max_value, reg->u32_max_value);
+	} else if ((s32)reg->u32_min_value < 0) {
+		/* Negative.  We can't learn anything from the smax, but smin
+		 * is negative, hence safe.
+		 */
+		reg->s32_min_value = reg->u32_min_value =
+			max_t(u32, reg->s32_min_value, reg->u32_min_value);
+		reg->s32_max_value = reg->u32_max_value;
+	}
+}
+
+static void __reg64_deduce_bounds(struct bpf_reg_state *reg)
+{
+	/* Learn sign from signed bounds.
+	 * If we cannot cross the sign boundary, then signed and unsigned bounds
+	 * are the same, so combine.  This works even in the negative case, e.g.
+	 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
+	 */
+	if (reg->smin_value >= 0 || reg->smax_value < 0) {
+		reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value,
+							  reg->umin_value);
+		reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value,
+							  reg->umax_value);
+		return;
+	}
+	/* Learn sign from unsigned bounds.  Signed bounds cross the sign
+	 * boundary, so we must be careful.
+	 */
+	if ((s64)reg->umax_value >= 0) {
+		/* Positive.  We can't learn anything from the smin, but smax
+		 * is positive, hence safe.
+		 */
+		reg->smin_value = reg->umin_value;
+		reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value,
+							  reg->umax_value);
+	} else if ((s64)reg->umin_value < 0) {
+		/* Negative.  We can't learn anything from the smax, but smin
+		 * is negative, hence safe.
+		 */
+		reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value,
+							  reg->umin_value);
+		reg->smax_value = reg->umax_value;
+	}
+}
+
+static void __reg_deduce_bounds(struct bpf_reg_state *reg)
+{
+	__reg32_deduce_bounds(reg);
+	__reg64_deduce_bounds(reg);
+}
+
+/* Attempts to improve var_off based on unsigned min/max information */
+static void __reg_bound_offset(struct bpf_reg_state *reg)
+{
+	struct tnum var64_off = tnum_intersect(reg->var_off,
+					       tnum_range(reg->umin_value,
+							  reg->umax_value));
+	struct tnum var32_off = tnum_intersect(tnum_subreg(var64_off),
+					       tnum_range(reg->u32_min_value,
+							  reg->u32_max_value));
+
+	reg->var_off = tnum_or(tnum_clear_subreg(var64_off), var32_off);
+}
+
+static void reg_bounds_sync(struct bpf_reg_state *reg)
+{
+	/* We might have learned new bounds from the var_off. */
+	__update_reg_bounds(reg);
+	/* We might have learned something about the sign bit. */
+	__reg_deduce_bounds(reg);
+	/* We might have learned some bits from the bounds. */
+	__reg_bound_offset(reg);
+	/* Intersecting with the old var_off might have improved our bounds
+	 * slightly, e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
+	 * then new var_off is (0; 0x7f...fc) which improves our umax.
+	 */
+	__update_reg_bounds(reg);
+}
+
+static bool __reg32_bound_s64(s32 a)
+{
+	return a >= 0 && a <= S32_MAX;
+}
+
+static void __reg_assign_32_into_64(struct bpf_reg_state *reg)
+{
+	reg->umin_value = reg->u32_min_value;
+	reg->umax_value = reg->u32_max_value;
+
+	/* Attempt to pull 32-bit signed bounds into 64-bit bounds but must
+	 * be positive otherwise set to worse case bounds and refine later
+	 * from tnum.
+	 */
+	if (__reg32_bound_s64(reg->s32_min_value) &&
+	    __reg32_bound_s64(reg->s32_max_value)) {
+		reg->smin_value = reg->s32_min_value;
+		reg->smax_value = reg->s32_max_value;
+	} else {
+		reg->smin_value = 0;
+		reg->smax_value = U32_MAX;
+	}
+}
+
+static void __reg_combine_32_into_64(struct bpf_reg_state *reg)
+{
+	/* special case when 64-bit register has upper 32-bit register
+	 * zeroed. Typically happens after zext or <<32, >>32 sequence
+	 * allowing us to use 32-bit bounds directly,
+	 */
+	if (tnum_equals_const(tnum_clear_subreg(reg->var_off), 0)) {
+		__reg_assign_32_into_64(reg);
+	} else {
+		/* Otherwise the best we can do is push lower 32bit known and
+		 * unknown bits into register (var_off set from jmp logic)
+		 * then learn as much as possible from the 64-bit tnum
+		 * known and unknown bits. The previous smin/smax bounds are
+		 * invalid here because of jmp32 compare so mark them unknown
+		 * so they do not impact tnum bounds calculation.
+		 */
+		__mark_reg64_unbounded(reg);
+	}
+	reg_bounds_sync(reg);
+}
+
+static bool __reg64_bound_s32(s64 a)
+{
+	return a >= S32_MIN && a <= S32_MAX;
+}
+
+static bool __reg64_bound_u32(u64 a)
+{
+	return a >= U32_MIN && a <= U32_MAX;
+}
+
+static void __reg_combine_64_into_32(struct bpf_reg_state *reg)
+{
+	__mark_reg32_unbounded(reg);
+	if (__reg64_bound_s32(reg->smin_value) && __reg64_bound_s32(reg->smax_value)) {
+		reg->s32_min_value = (s32)reg->smin_value;
+		reg->s32_max_value = (s32)reg->smax_value;
+	}
+	if (__reg64_bound_u32(reg->umin_value) && __reg64_bound_u32(reg->umax_value)) {
+		reg->u32_min_value = (u32)reg->umin_value;
+		reg->u32_max_value = (u32)reg->umax_value;
+	}
+	reg_bounds_sync(reg);
+}
+
+/* Mark a register as having a completely unknown (scalar) value. */
+static void __mark_reg_unknown(const struct bpf_verifier_env *env,
+			       struct bpf_reg_state *reg)
+{
+	/*
+	 * Clear type, id, off, and union(map_ptr, range) and
+	 * padding between 'type' and union
+	 */
+	memset(reg, 0, offsetof(struct bpf_reg_state, var_off));
+	reg->type = SCALAR_VALUE;
+	reg->var_off = tnum_unknown;
+	reg->frameno = 0;
+	reg->precise = !env->bpf_capable;
+	__mark_reg_unbounded(reg);
+}
+
+static void mark_reg_unknown(struct bpf_verifier_env *env,
+			     struct bpf_reg_state *regs, u32 regno)
+{
+	if (WARN_ON(regno >= MAX_BPF_REG)) {
+		verbose(env, "mark_reg_unknown(regs, %u)\n", regno);
+		/* Something bad happened, let's kill all regs except FP */
+		for (regno = 0; regno < BPF_REG_FP; regno++)
+			__mark_reg_not_init(env, regs + regno);
+		return;
+	}
+	__mark_reg_unknown(env, regs + regno);
+}
+
+static void __mark_reg_not_init(const struct bpf_verifier_env *env,
+				struct bpf_reg_state *reg)
+{
+	__mark_reg_unknown(env, reg);
+	reg->type = NOT_INIT;
+}
+
+static void mark_reg_not_init(struct bpf_verifier_env *env,
+			      struct bpf_reg_state *regs, u32 regno)
+{
+	if (WARN_ON(regno >= MAX_BPF_REG)) {
+		verbose(env, "mark_reg_not_init(regs, %u)\n", regno);
+		/* Something bad happened, let's kill all regs except FP */
+		for (regno = 0; regno < BPF_REG_FP; regno++)
+			__mark_reg_not_init(env, regs + regno);
+		return;
+	}
+	__mark_reg_not_init(env, regs + regno);
+}
+
+static void mark_btf_ld_reg(struct bpf_verifier_env *env,
+			    struct bpf_reg_state *regs, u32 regno,
+			    enum bpf_reg_type reg_type,
+			    struct btf *btf, u32 btf_id,
+			    enum bpf_type_flag flag)
+{
+	if (reg_type == SCALAR_VALUE) {
+		mark_reg_unknown(env, regs, regno);
+		return;
+	}
+	mark_reg_known_zero(env, regs, regno);
+	regs[regno].type = PTR_TO_BTF_ID | flag;
+	regs[regno].btf = btf;
+	regs[regno].btf_id = btf_id;
+}
+
+#define DEF_NOT_SUBREG	(0)
+static void init_reg_state(struct bpf_verifier_env *env,
+			   struct bpf_func_state *state)
+{
+	struct bpf_reg_state *regs = state->regs;
+	int i;
+
+	for (i = 0; i < MAX_BPF_REG; i++) {
+		mark_reg_not_init(env, regs, i);
+		regs[i].live = REG_LIVE_NONE;
+		regs[i].parent = NULL;
+		regs[i].subreg_def = DEF_NOT_SUBREG;
+	}
+
+	/* frame pointer */
+	regs[BPF_REG_FP].type = PTR_TO_STACK;
+	mark_reg_known_zero(env, regs, BPF_REG_FP);
+	regs[BPF_REG_FP].frameno = state->frameno;
+}
+
+#define BPF_MAIN_FUNC (-1)
+static void init_func_state(struct bpf_verifier_env *env,
+			    struct bpf_func_state *state,
+			    int callsite, int frameno, int subprogno)
+{
+	state->callsite = callsite;
+	state->frameno = frameno;
+	state->subprogno = subprogno;
+	state->callback_ret_range = tnum_range(0, 0);
+	init_reg_state(env, state);
+	mark_verifier_state_scratched(env);
+}
+
+/* Similar to push_stack(), but for async callbacks */
+static struct bpf_verifier_state *push_async_cb(struct bpf_verifier_env *env,
+						int insn_idx, int prev_insn_idx,
+						int subprog)
+{
+	struct bpf_verifier_stack_elem *elem;
+	struct bpf_func_state *frame;
+
+	elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL);
+	if (!elem)
+		goto err;
+
+	elem->insn_idx = insn_idx;
+	elem->prev_insn_idx = prev_insn_idx;
+	elem->next = env->head;
+	elem->log_pos = env->log.len_used;
+	env->head = elem;
+	env->stack_size++;
+	if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) {
+		verbose(env,
+			"The sequence of %d jumps is too complex for async cb.\n",
+			env->stack_size);
+		goto err;
+	}
+	/* Unlike push_stack() do not copy_verifier_state().
+	 * The caller state doesn't matter.
+	 * This is async callback. It starts in a fresh stack.
+	 * Initialize it similar to do_check_common().
+	 */
+	elem->st.branches = 1;
+	frame = kzalloc(sizeof(*frame), GFP_KERNEL);
+	if (!frame)
+		goto err;
+	init_func_state(env, frame,
+			BPF_MAIN_FUNC /* callsite */,
+			0 /* frameno within this callchain */,
+			subprog /* subprog number within this prog */);
+	elem->st.frame[0] = frame;
+	return &elem->st;
+err:
+	free_verifier_state(env->cur_state, true);
+	env->cur_state = NULL;
+	/* pop all elements and return */
+	while (!pop_stack(env, NULL, NULL, false));
+	return NULL;
+}
+
+
+enum reg_arg_type {
+	SRC_OP,		/* register is used as source operand */
+	DST_OP,		/* register is used as destination operand */
+	DST_OP_NO_MARK	/* same as above, check only, don't mark */
+};
+
+static int cmp_subprogs(const void *a, const void *b)
+{
+	return ((struct bpf_subprog_info *)a)->start -
+	       ((struct bpf_subprog_info *)b)->start;
+}
+
+static int find_subprog(struct bpf_verifier_env *env, int off)
+{
+	struct bpf_subprog_info *p;
+
+	p = bsearch(&off, env->subprog_info, env->subprog_cnt,
+		    sizeof(env->subprog_info[0]), cmp_subprogs);
+	if (!p)
+		return -ENOENT;
+	return p - env->subprog_info;
+
+}
+
+static int add_subprog(struct bpf_verifier_env *env, int off)
+{
+	int insn_cnt = env->prog->len;
+	int ret;
+
+	if (off >= insn_cnt || off < 0) {
+		verbose(env, "call to invalid destination\n");
+		return -EINVAL;
+	}
+	ret = find_subprog(env, off);
+	if (ret >= 0)
+		return ret;
+	if (env->subprog_cnt >= BPF_MAX_SUBPROGS) {
+		verbose(env, "too many subprograms\n");
+		return -E2BIG;
+	}
+	/* determine subprog starts. The end is one before the next starts */
+	env->subprog_info[env->subprog_cnt++].start = off;
+	sort(env->subprog_info, env->subprog_cnt,
+	     sizeof(env->subprog_info[0]), cmp_subprogs, NULL);
+	return env->subprog_cnt - 1;
+}
+
+#define MAX_KFUNC_DESCS 256
+#define MAX_KFUNC_BTFS	256
+
+struct bpf_kfunc_desc {
+	struct btf_func_model func_model;
+	u32 func_id;
+	s32 imm;
+	u16 offset;
+};
+
+struct bpf_kfunc_btf {
+	struct btf *btf;
+	struct module *module;
+	u16 offset;
+};
+
+struct bpf_kfunc_desc_tab {
+	struct bpf_kfunc_desc descs[MAX_KFUNC_DESCS];
+	u32 nr_descs;
+};
+
+struct bpf_kfunc_btf_tab {
+	struct bpf_kfunc_btf descs[MAX_KFUNC_BTFS];
+	u32 nr_descs;
+};
+
+static int kfunc_desc_cmp_by_id_off(const void *a, const void *b)
+{
+	const struct bpf_kfunc_desc *d0 = a;
+	const struct bpf_kfunc_desc *d1 = b;
+
+	/* func_id is not greater than BTF_MAX_TYPE */
+	return d0->func_id - d1->func_id ?: d0->offset - d1->offset;
+}
+
+static int kfunc_btf_cmp_by_off(const void *a, const void *b)
+{
+	const struct bpf_kfunc_btf *d0 = a;
+	const struct bpf_kfunc_btf *d1 = b;
+
+	return d0->offset - d1->offset;
+}
+
+static const struct bpf_kfunc_desc *
+find_kfunc_desc(const struct bpf_prog *prog, u32 func_id, u16 offset)
+{
+	struct bpf_kfunc_desc desc = {
+		.func_id = func_id,
+		.offset = offset,
+	};
+	struct bpf_kfunc_desc_tab *tab;
+
+	tab = prog->aux->kfunc_tab;
+	return bsearch(&desc, tab->descs, tab->nr_descs,
+		       sizeof(tab->descs[0]), kfunc_desc_cmp_by_id_off);
+}
+
+static struct btf *__find_kfunc_desc_btf(struct bpf_verifier_env *env,
+					 s16 offset)
+{
+	struct bpf_kfunc_btf kf_btf = { .offset = offset };
+	struct bpf_kfunc_btf_tab *tab;
+	struct bpf_kfunc_btf *b;
+	struct module *mod;
+	struct btf *btf;
+	int btf_fd;
+
+	tab = env->prog->aux->kfunc_btf_tab;
+	b = bsearch(&kf_btf, tab->descs, tab->nr_descs,
+		    sizeof(tab->descs[0]), kfunc_btf_cmp_by_off);
+	if (!b) {
+		if (tab->nr_descs == MAX_KFUNC_BTFS) {
+			verbose(env, "too many different module BTFs\n");
+			return ERR_PTR(-E2BIG);
+		}
+
+		if (bpfptr_is_null(env->fd_array)) {
+			verbose(env, "kfunc offset > 0 without fd_array is invalid\n");
+			return ERR_PTR(-EPROTO);
+		}
+
+		if (copy_from_bpfptr_offset(&btf_fd, env->fd_array,
+					    offset * sizeof(btf_fd),
+					    sizeof(btf_fd)))
+			return ERR_PTR(-EFAULT);
+
+		btf = btf_get_by_fd(btf_fd);
+		if (IS_ERR(btf)) {
+			verbose(env, "invalid module BTF fd specified\n");
+			return btf;
+		}
+
+		if (!btf_is_module(btf)) {
+			verbose(env, "BTF fd for kfunc is not a module BTF\n");
+			btf_put(btf);
+			return ERR_PTR(-EINVAL);
+		}
+
+		mod = btf_try_get_module(btf);
+		if (!mod) {
+			btf_put(btf);
+			return ERR_PTR(-ENXIO);
+		}
+
+		b = &tab->descs[tab->nr_descs++];
+		b->btf = btf;
+		b->module = mod;
+		b->offset = offset;
+
+		sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
+		     kfunc_btf_cmp_by_off, NULL);
+	}
+	return b->btf;
+}
+
+void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab)
+{
+	if (!tab)
+		return;
+
+	while (tab->nr_descs--) {
+		module_put(tab->descs[tab->nr_descs].module);
+		btf_put(tab->descs[tab->nr_descs].btf);
+	}
+	kfree(tab);
+}
+
+static struct btf *find_kfunc_desc_btf(struct bpf_verifier_env *env, s16 offset)
+{
+	if (offset) {
+		if (offset < 0) {
+			/* In the future, this can be allowed to increase limit
+			 * of fd index into fd_array, interpreted as u16.
+			 */
+			verbose(env, "negative offset disallowed for kernel module function call\n");
+			return ERR_PTR(-EINVAL);
+		}
+
+		return __find_kfunc_desc_btf(env, offset);
+	}
+	return btf_vmlinux ?: ERR_PTR(-ENOENT);
+}
+
+static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id, s16 offset)
+{
+	const struct btf_type *func, *func_proto;
+	struct bpf_kfunc_btf_tab *btf_tab;
+	struct bpf_kfunc_desc_tab *tab;
+	struct bpf_prog_aux *prog_aux;
+	struct bpf_kfunc_desc *desc;
+	const char *func_name;
+	struct btf *desc_btf;
+	unsigned long call_imm;
+	unsigned long addr;
+	int err;
+
+	prog_aux = env->prog->aux;
+	tab = prog_aux->kfunc_tab;
+	btf_tab = prog_aux->kfunc_btf_tab;
+	if (!tab) {
+		if (!btf_vmlinux) {
+			verbose(env, "calling kernel function is not supported without CONFIG_DEBUG_INFO_BTF\n");
+			return -ENOTSUPP;
+		}
+
+		if (!env->prog->jit_requested) {
+			verbose(env, "JIT is required for calling kernel function\n");
+			return -ENOTSUPP;
+		}
+
+		if (!bpf_jit_supports_kfunc_call()) {
+			verbose(env, "JIT does not support calling kernel function\n");
+			return -ENOTSUPP;
+		}
+
+		if (!env->prog->gpl_compatible) {
+			verbose(env, "cannot call kernel function from non-GPL compatible program\n");
+			return -EINVAL;
+		}
+
+		tab = kzalloc(sizeof(*tab), GFP_KERNEL);
+		if (!tab)
+			return -ENOMEM;
+		prog_aux->kfunc_tab = tab;
+	}
+
+	/* func_id == 0 is always invalid, but instead of returning an error, be
+	 * conservative and wait until the code elimination pass before returning
+	 * error, so that invalid calls that get pruned out can be in BPF programs
+	 * loaded from userspace.  It is also required that offset be untouched
+	 * for such calls.
+	 */
+	if (!func_id && !offset)
+		return 0;
+
+	if (!btf_tab && offset) {
+		btf_tab = kzalloc(sizeof(*btf_tab), GFP_KERNEL);
+		if (!btf_tab)
+			return -ENOMEM;
+		prog_aux->kfunc_btf_tab = btf_tab;
+	}
+
+	desc_btf = find_kfunc_desc_btf(env, offset);
+	if (IS_ERR(desc_btf)) {
+		verbose(env, "failed to find BTF for kernel function\n");
+		return PTR_ERR(desc_btf);
+	}
+
+	if (find_kfunc_desc(env->prog, func_id, offset))
+		return 0;
+
+	if (tab->nr_descs == MAX_KFUNC_DESCS) {
+		verbose(env, "too many different kernel function calls\n");
+		return -E2BIG;
+	}
+
+	func = btf_type_by_id(desc_btf, func_id);
+	if (!func || !btf_type_is_func(func)) {
+		verbose(env, "kernel btf_id %u is not a function\n",
+			func_id);
+		return -EINVAL;
+	}
+	func_proto = btf_type_by_id(desc_btf, func->type);
+	if (!func_proto || !btf_type_is_func_proto(func_proto)) {
+		verbose(env, "kernel function btf_id %u does not have a valid func_proto\n",
+			func_id);
+		return -EINVAL;
+	}
+
+	func_name = btf_name_by_offset(desc_btf, func->name_off);
+	addr = kallsyms_lookup_name(func_name);
+	if (!addr) {
+		verbose(env, "cannot find address for kernel function %s\n",
+			func_name);
+		return -EINVAL;
+	}
+
+	call_imm = BPF_CALL_IMM(addr);
+	/* Check whether or not the relative offset overflows desc->imm */
+	if ((unsigned long)(s32)call_imm != call_imm) {
+		verbose(env, "address of kernel function %s is out of range\n",
+			func_name);
+		return -EINVAL;
+	}
+
+	desc = &tab->descs[tab->nr_descs++];
+	desc->func_id = func_id;
+	desc->imm = call_imm;
+	desc->offset = offset;
+	err = btf_distill_func_proto(&env->log, desc_btf,
+				     func_proto, func_name,
+				     &desc->func_model);
+	if (!err)
+		sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
+		     kfunc_desc_cmp_by_id_off, NULL);
+	return err;
+}
+
+static int kfunc_desc_cmp_by_imm(const void *a, const void *b)
+{
+	const struct bpf_kfunc_desc *d0 = a;
+	const struct bpf_kfunc_desc *d1 = b;
+
+	if (d0->imm > d1->imm)
+		return 1;
+	else if (d0->imm < d1->imm)
+		return -1;
+	return 0;
+}
+
+static void sort_kfunc_descs_by_imm(struct bpf_prog *prog)
+{
+	struct bpf_kfunc_desc_tab *tab;
+
+	tab = prog->aux->kfunc_tab;
+	if (!tab)
+		return;
+
+	sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
+	     kfunc_desc_cmp_by_imm, NULL);
+}
+
+bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog)
+{
+	return !!prog->aux->kfunc_tab;
+}
+
+const struct btf_func_model *
+bpf_jit_find_kfunc_model(const struct bpf_prog *prog,
+			 const struct bpf_insn *insn)
+{
+	const struct bpf_kfunc_desc desc = {
+		.imm = insn->imm,
+	};
+	const struct bpf_kfunc_desc *res;
+	struct bpf_kfunc_desc_tab *tab;
+
+	tab = prog->aux->kfunc_tab;
+	res = bsearch(&desc, tab->descs, tab->nr_descs,
+		      sizeof(tab->descs[0]), kfunc_desc_cmp_by_imm);
+
+	return res ? &res->func_model : NULL;
+}
+
+static int add_subprog_and_kfunc(struct bpf_verifier_env *env)
+{
+	struct bpf_subprog_info *subprog = env->subprog_info;
+	struct bpf_insn *insn = env->prog->insnsi;
+	int i, ret, insn_cnt = env->prog->len;
+
+	/* Add entry function. */
+	ret = add_subprog(env, 0);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn) &&
+		    !bpf_pseudo_kfunc_call(insn))
+			continue;
+
+		if (!env->bpf_capable) {
+			verbose(env, "loading/calling other bpf or kernel functions are allowed for CAP_BPF and CAP_SYS_ADMIN\n");
+			return -EPERM;
+		}
+
+		if (bpf_pseudo_func(insn) || bpf_pseudo_call(insn))
+			ret = add_subprog(env, i + insn->imm + 1);
+		else
+			ret = add_kfunc_call(env, insn->imm, insn->off);
+
+		if (ret < 0)
+			return ret;
+	}
+
+	/* Add a fake 'exit' subprog which could simplify subprog iteration
+	 * logic. 'subprog_cnt' should not be increased.
+	 */
+	subprog[env->subprog_cnt].start = insn_cnt;
+
+	if (env->log.level & BPF_LOG_LEVEL2)
+		for (i = 0; i < env->subprog_cnt; i++)
+			verbose(env, "func#%d @%d\n", i, subprog[i].start);
+
+	return 0;
+}
+
+static int check_subprogs(struct bpf_verifier_env *env)
+{
+	int i, subprog_start, subprog_end, off, cur_subprog = 0;
+	struct bpf_subprog_info *subprog = env->subprog_info;
+	struct bpf_insn *insn = env->prog->insnsi;
+	int insn_cnt = env->prog->len;
+
+	/* now check that all jumps are within the same subprog */
+	subprog_start = subprog[cur_subprog].start;
+	subprog_end = subprog[cur_subprog + 1].start;
+	for (i = 0; i < insn_cnt; i++) {
+		u8 code = insn[i].code;
+
+		if (code == (BPF_JMP | BPF_CALL) &&
+		    insn[i].imm == BPF_FUNC_tail_call &&
+		    insn[i].src_reg != BPF_PSEUDO_CALL)
+			subprog[cur_subprog].has_tail_call = true;
+		if (BPF_CLASS(code) == BPF_LD &&
+		    (BPF_MODE(code) == BPF_ABS || BPF_MODE(code) == BPF_IND))
+			subprog[cur_subprog].has_ld_abs = true;
+		if (BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32)
+			goto next;
+		if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL)
+			goto next;
+		if (code == (BPF_JMP32 | BPF_JA))
+			off = i + insn[i].imm + 1;
+		else
+			off = i + insn[i].off + 1;
+		if (off < subprog_start || off >= subprog_end) {
+			verbose(env, "jump out of range from insn %d to %d\n", i, off);
+			return -EINVAL;
+		}
+next:
+		if (i == subprog_end - 1) {
+			/* to avoid fall-through from one subprog into another
+			 * the last insn of the subprog should be either exit
+			 * or unconditional jump back
+			 */
+			if (code != (BPF_JMP | BPF_EXIT) &&
+			    code != (BPF_JMP32 | BPF_JA) &&
+			    code != (BPF_JMP | BPF_JA)) {
+				verbose(env, "last insn is not an exit or jmp\n");
+				return -EINVAL;
+			}
+			subprog_start = subprog_end;
+			cur_subprog++;
+			if (cur_subprog < env->subprog_cnt)
+				subprog_end = subprog[cur_subprog + 1].start;
+		}
+	}
+	return 0;
+}
+
+/* Parentage chain of this register (or stack slot) should take care of all
+ * issues like callee-saved registers, stack slot allocation time, etc.
+ */
+static int mark_reg_read(struct bpf_verifier_env *env,
+			 const struct bpf_reg_state *state,
+			 struct bpf_reg_state *parent, u8 flag)
+{
+	bool writes = parent == state->parent; /* Observe write marks */
+	int cnt = 0;
+
+	while (parent) {
+		/* if read wasn't screened by an earlier write ... */
+		if (writes && state->live & REG_LIVE_WRITTEN)
+			break;
+		if (parent->live & REG_LIVE_DONE) {
+			verbose(env, "verifier BUG type %s var_off %lld off %d\n",
+				reg_type_str(env, parent->type),
+				parent->var_off.value, parent->off);
+			return -EFAULT;
+		}
+		/* The first condition is more likely to be true than the
+		 * second, checked it first.
+		 */
+		if ((parent->live & REG_LIVE_READ) == flag ||
+		    parent->live & REG_LIVE_READ64)
+			/* The parentage chain never changes and
+			 * this parent was already marked as LIVE_READ.
+			 * There is no need to keep walking the chain again and
+			 * keep re-marking all parents as LIVE_READ.
+			 * This case happens when the same register is read
+			 * multiple times without writes into it in-between.
+			 * Also, if parent has the stronger REG_LIVE_READ64 set,
+			 * then no need to set the weak REG_LIVE_READ32.
+			 */
+			break;
+		/* ... then we depend on parent's value */
+		parent->live |= flag;
+		/* REG_LIVE_READ64 overrides REG_LIVE_READ32. */
+		if (flag == REG_LIVE_READ64)
+			parent->live &= ~REG_LIVE_READ32;
+		state = parent;
+		parent = state->parent;
+		writes = true;
+		cnt++;
+	}
+
+	if (env->longest_mark_read_walk < cnt)
+		env->longest_mark_read_walk = cnt;
+	return 0;
+}
+
+/* This function is supposed to be used by the following 32-bit optimization
+ * code only. It returns TRUE if the source or destination register operates
+ * on 64-bit, otherwise return FALSE.
+ */
+static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn,
+		     u32 regno, struct bpf_reg_state *reg, enum reg_arg_type t)
+{
+	u8 code, class, op;
+
+	code = insn->code;
+	class = BPF_CLASS(code);
+	op = BPF_OP(code);
+	if (class == BPF_JMP) {
+		/* BPF_EXIT for "main" will reach here. Return TRUE
+		 * conservatively.
+		 */
+		if (op == BPF_EXIT)
+			return true;
+		if (op == BPF_CALL) {
+			/* BPF to BPF call will reach here because of marking
+			 * caller saved clobber with DST_OP_NO_MARK for which we
+			 * don't care the register def because they are anyway
+			 * marked as NOT_INIT already.
+			 */
+			if (insn->src_reg == BPF_PSEUDO_CALL)
+				return false;
+			/* Helper call will reach here because of arg type
+			 * check, conservatively return TRUE.
+			 */
+			if (t == SRC_OP)
+				return true;
+
+			return false;
+		}
+	}
+
+	if (class == BPF_ALU64 || class == BPF_JMP ||
+	    /* BPF_END always use BPF_ALU class. */
+	    (class == BPF_ALU && op == BPF_END && insn->imm == 64))
+		return true;
+
+	if (class == BPF_ALU || class == BPF_JMP32)
+		return false;
+
+	if (class == BPF_LDX) {
+		if (t != SRC_OP)
+			return BPF_SIZE(code) == BPF_DW;
+		/* LDX source must be ptr. */
+		return true;
+	}
+
+	if (class == BPF_STX) {
+		/* BPF_STX (including atomic variants) has multiple source
+		 * operands, one of which is a ptr. Check whether the caller is
+		 * asking about it.
+		 */
+		if (t == SRC_OP && reg->type != SCALAR_VALUE)
+			return true;
+		return BPF_SIZE(code) == BPF_DW;
+	}
+
+	if (class == BPF_LD) {
+		u8 mode = BPF_MODE(code);
+
+		/* LD_IMM64 */
+		if (mode == BPF_IMM)
+			return true;
+
+		/* Both LD_IND and LD_ABS return 32-bit data. */
+		if (t != SRC_OP)
+			return  false;
+
+		/* Implicit ctx ptr. */
+		if (regno == BPF_REG_6)
+			return true;
+
+		/* Explicit source could be any width. */
+		return true;
+	}
+
+	if (class == BPF_ST)
+		/* The only source register for BPF_ST is a ptr. */
+		return true;
+
+	/* Conservatively return true at default. */
+	return true;
+}
+
+/* Return the regno defined by the insn, or -1. */
+static int insn_def_regno(const struct bpf_insn *insn)
+{
+	switch (BPF_CLASS(insn->code)) {
+	case BPF_JMP:
+	case BPF_JMP32:
+	case BPF_ST:
+		return -1;
+	case BPF_STX:
+		if (BPF_MODE(insn->code) == BPF_ATOMIC &&
+		    (insn->imm & BPF_FETCH)) {
+			if (insn->imm == BPF_CMPXCHG)
+				return BPF_REG_0;
+			else
+				return insn->src_reg;
+		} else {
+			return -1;
+		}
+	default:
+		return insn->dst_reg;
+	}
+}
+
+/* Return TRUE if INSN has defined any 32-bit value explicitly. */
+static bool insn_has_def32(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+	int dst_reg = insn_def_regno(insn);
+
+	if (dst_reg == -1)
+		return false;
+
+	return !is_reg64(env, insn, dst_reg, NULL, DST_OP);
+}
+
+static void mark_insn_zext(struct bpf_verifier_env *env,
+			   struct bpf_reg_state *reg)
+{
+	s32 def_idx = reg->subreg_def;
+
+	if (def_idx == DEF_NOT_SUBREG)
+		return;
+
+	env->insn_aux_data[def_idx - 1].zext_dst = true;
+	/* The dst will be zero extended, so won't be sub-register anymore. */
+	reg->subreg_def = DEF_NOT_SUBREG;
+}
+
+static int check_reg_arg(struct bpf_verifier_env *env, u32 regno,
+			 enum reg_arg_type t)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_insn *insn = env->prog->insnsi + env->insn_idx;
+	struct bpf_reg_state *reg, *regs = state->regs;
+	bool rw64;
+
+	if (regno >= MAX_BPF_REG) {
+		verbose(env, "R%d is invalid\n", regno);
+		return -EINVAL;
+	}
+
+	mark_reg_scratched(env, regno);
+
+	reg = &regs[regno];
+	rw64 = is_reg64(env, insn, regno, reg, t);
+	if (t == SRC_OP) {
+		/* check whether register used as source operand can be read */
+		if (reg->type == NOT_INIT) {
+			verbose(env, "R%d !read_ok\n", regno);
+			return -EACCES;
+		}
+		/* We don't need to worry about FP liveness because it's read-only */
+		if (regno == BPF_REG_FP)
+			return 0;
+
+		if (rw64)
+			mark_insn_zext(env, reg);
+
+		return mark_reg_read(env, reg, reg->parent,
+				     rw64 ? REG_LIVE_READ64 : REG_LIVE_READ32);
+	} else {
+		/* check whether register used as dest operand can be written to */
+		if (regno == BPF_REG_FP) {
+			verbose(env, "frame pointer is read only\n");
+			return -EACCES;
+		}
+		reg->live |= REG_LIVE_WRITTEN;
+		reg->subreg_def = rw64 ? DEF_NOT_SUBREG : env->insn_idx + 1;
+		if (t == DST_OP)
+			mark_reg_unknown(env, regs, regno);
+	}
+	return 0;
+}
+
+static void mark_jmp_point(struct bpf_verifier_env *env, int idx)
+{
+	env->insn_aux_data[idx].jmp_point = true;
+}
+
+static bool is_jmp_point(struct bpf_verifier_env *env, int insn_idx)
+{
+	return env->insn_aux_data[insn_idx].jmp_point;
+}
+
+/* for any branch, call, exit record the history of jmps in the given state */
+static int push_jmp_history(struct bpf_verifier_env *env,
+			    struct bpf_verifier_state *cur)
+{
+	u32 cnt = cur->jmp_history_cnt;
+	struct bpf_idx_pair *p;
+	size_t alloc_size;
+
+	if (!is_jmp_point(env, env->insn_idx))
+		return 0;
+
+	cnt++;
+	alloc_size = kmalloc_size_roundup(size_mul(cnt, sizeof(*p)));
+	p = krealloc(cur->jmp_history, alloc_size, GFP_USER);
+	if (!p)
+		return -ENOMEM;
+	p[cnt - 1].idx = env->insn_idx;
+	p[cnt - 1].prev_idx = env->prev_insn_idx;
+	cur->jmp_history = p;
+	cur->jmp_history_cnt = cnt;
+	return 0;
+}
+
+/* Backtrack one insn at a time. If idx is not at the top of recorded
+ * history then previous instruction came from straight line execution.
+ * Return -ENOENT if we exhausted all instructions within given state.
+ *
+ * It's legal to have a bit of a looping with the same starting and ending
+ * insn index within the same state, e.g.: 3->4->5->3, so just because current
+ * instruction index is the same as state's first_idx doesn't mean we are
+ * done. If there is still some jump history left, we should keep going. We
+ * need to take into account that we might have a jump history between given
+ * state's parent and itself, due to checkpointing. In this case, we'll have
+ * history entry recording a jump from last instruction of parent state and
+ * first instruction of given state.
+ */
+static int get_prev_insn_idx(struct bpf_verifier_state *st, int i,
+			     u32 *history)
+{
+	u32 cnt = *history;
+
+	if (i == st->first_insn_idx) {
+		if (cnt == 0)
+			return -ENOENT;
+		if (cnt == 1 && st->jmp_history[0].idx == i)
+			return -ENOENT;
+	}
+
+	if (cnt && st->jmp_history[cnt - 1].idx == i) {
+		i = st->jmp_history[cnt - 1].prev_idx;
+		(*history)--;
+	} else {
+		i--;
+	}
+	return i;
+}
+
+static const char *disasm_kfunc_name(void *data, const struct bpf_insn *insn)
+{
+	const struct btf_type *func;
+	struct btf *desc_btf;
+
+	if (insn->src_reg != BPF_PSEUDO_KFUNC_CALL)
+		return NULL;
+
+	desc_btf = find_kfunc_desc_btf(data, insn->off);
+	if (IS_ERR(desc_btf))
+		return "<error>";
+
+	func = btf_type_by_id(desc_btf, insn->imm);
+	return btf_name_by_offset(desc_btf, func->name_off);
+}
+
+/* For given verifier state backtrack_insn() is called from the last insn to
+ * the first insn. Its purpose is to compute a bitmask of registers and
+ * stack slots that needs precision in the parent verifier state.
+ */
+static int backtrack_insn(struct bpf_verifier_env *env, int idx,
+			  u32 *reg_mask, u64 *stack_mask)
+{
+	const struct bpf_insn_cbs cbs = {
+		.cb_call	= disasm_kfunc_name,
+		.cb_print	= verbose,
+		.private_data	= env,
+	};
+	struct bpf_insn *insn = env->prog->insnsi + idx;
+	u8 class = BPF_CLASS(insn->code);
+	u8 opcode = BPF_OP(insn->code);
+	u8 mode = BPF_MODE(insn->code);
+	u32 dreg = 1u << insn->dst_reg;
+	u32 sreg = 1u << insn->src_reg;
+	u32 spi;
+
+	if (insn->code == 0)
+		return 0;
+	if (env->log.level & BPF_LOG_LEVEL2) {
+		verbose(env, "regs=%x stack=%llx before ", *reg_mask, *stack_mask);
+		verbose(env, "%d: ", idx);
+		print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
+	}
+
+	if (class == BPF_ALU || class == BPF_ALU64) {
+		if (!(*reg_mask & dreg))
+			return 0;
+		if (opcode == BPF_END || opcode == BPF_NEG) {
+			/* sreg is reserved and unused
+			 * dreg still need precision before this insn
+			 */
+			return 0;
+		} else if (opcode == BPF_MOV) {
+			if (BPF_SRC(insn->code) == BPF_X) {
+				/* dreg = sreg
+				 * dreg needs precision after this insn
+				 * sreg needs precision before this insn
+				 */
+				*reg_mask &= ~dreg;
+				*reg_mask |= sreg;
+			} else {
+				/* dreg = K
+				 * dreg needs precision after this insn.
+				 * Corresponding register is already marked
+				 * as precise=true in this verifier state.
+				 * No further markings in parent are necessary
+				 */
+				*reg_mask &= ~dreg;
+			}
+		} else {
+			if (BPF_SRC(insn->code) == BPF_X) {
+				/* dreg += sreg
+				 * both dreg and sreg need precision
+				 * before this insn
+				 */
+				*reg_mask |= sreg;
+			} /* else dreg += K
+			   * dreg still needs precision before this insn
+			   */
+		}
+	} else if (class == BPF_LDX) {
+		if (!(*reg_mask & dreg))
+			return 0;
+		*reg_mask &= ~dreg;
+
+		/* scalars can only be spilled into stack w/o losing precision.
+		 * Load from any other memory can be zero extended.
+		 * The desire to keep that precision is already indicated
+		 * by 'precise' mark in corresponding register of this state.
+		 * No further tracking necessary.
+		 */
+		if (insn->src_reg != BPF_REG_FP)
+			return 0;
+
+		/* dreg = *(u64 *)[fp - off] was a fill from the stack.
+		 * that [fp - off] slot contains scalar that needs to be
+		 * tracked with precision
+		 */
+		spi = (-insn->off - 1) / BPF_REG_SIZE;
+		if (spi >= 64) {
+			verbose(env, "BUG spi %d\n", spi);
+			WARN_ONCE(1, "verifier backtracking bug");
+			return -EFAULT;
+		}
+		*stack_mask |= 1ull << spi;
+	} else if (class == BPF_STX || class == BPF_ST) {
+		if (*reg_mask & dreg)
+			/* stx & st shouldn't be using _scalar_ dst_reg
+			 * to access memory. It means backtracking
+			 * encountered a case of pointer subtraction.
+			 */
+			return -ENOTSUPP;
+		/* scalars can only be spilled into stack */
+		if (insn->dst_reg != BPF_REG_FP)
+			return 0;
+		spi = (-insn->off - 1) / BPF_REG_SIZE;
+		if (spi >= 64) {
+			verbose(env, "BUG spi %d\n", spi);
+			WARN_ONCE(1, "verifier backtracking bug");
+			return -EFAULT;
+		}
+		if (!(*stack_mask & (1ull << spi)))
+			return 0;
+		*stack_mask &= ~(1ull << spi);
+		if (class == BPF_STX)
+			*reg_mask |= sreg;
+	} else if (class == BPF_JMP || class == BPF_JMP32) {
+		if (opcode == BPF_CALL) {
+			if (insn->src_reg == BPF_PSEUDO_CALL)
+				return -ENOTSUPP;
+			/* kfunc with imm==0 is invalid and fixup_kfunc_call will
+			 * catch this error later. Make backtracking conservative
+			 * with ENOTSUPP.
+			 */
+			if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && insn->imm == 0)
+				return -ENOTSUPP;
+			/* BPF helpers that invoke callback subprogs are
+			 * equivalent to BPF_PSEUDO_CALL above
+			 */
+			if (insn->src_reg == 0 && is_callback_calling_function(insn->imm))
+				return -ENOTSUPP;
+			/* regular helper call sets R0 */
+			*reg_mask &= ~1;
+			if (*reg_mask & 0x3f) {
+				/* if backtracing was looking for registers R1-R5
+				 * they should have been found already.
+				 */
+				verbose(env, "BUG regs %x\n", *reg_mask);
+				WARN_ONCE(1, "verifier backtracking bug");
+				return -EFAULT;
+			}
+		} else if (opcode == BPF_EXIT) {
+			return -ENOTSUPP;
+		} else if (BPF_SRC(insn->code) == BPF_X) {
+			if (!(*reg_mask & (dreg | sreg)))
+				return 0;
+			/* dreg <cond> sreg
+			 * Both dreg and sreg need precision before
+			 * this insn. If only sreg was marked precise
+			 * before it would be equally necessary to
+			 * propagate it to dreg.
+			 */
+			*reg_mask |= (sreg | dreg);
+			 /* else dreg <cond> K
+			  * Only dreg still needs precision before
+			  * this insn, so for the K-based conditional
+			  * there is nothing new to be marked.
+			  */
+		}
+	} else if (class == BPF_LD) {
+		if (!(*reg_mask & dreg))
+			return 0;
+		*reg_mask &= ~dreg;
+		/* It's ld_imm64 or ld_abs or ld_ind.
+		 * For ld_imm64 no further tracking of precision
+		 * into parent is necessary
+		 */
+		if (mode == BPF_IND || mode == BPF_ABS)
+			/* to be analyzed */
+			return -ENOTSUPP;
+	}
+	return 0;
+}
+
+/* the scalar precision tracking algorithm:
+ * . at the start all registers have precise=false.
+ * . scalar ranges are tracked as normal through alu and jmp insns.
+ * . once precise value of the scalar register is used in:
+ *   .  ptr + scalar alu
+ *   . if (scalar cond K|scalar)
+ *   .  helper_call(.., scalar, ...) where ARG_CONST is expected
+ *   backtrack through the verifier states and mark all registers and
+ *   stack slots with spilled constants that these scalar regisers
+ *   should be precise.
+ * . during state pruning two registers (or spilled stack slots)
+ *   are equivalent if both are not precise.
+ *
+ * Note the verifier cannot simply walk register parentage chain,
+ * since many different registers and stack slots could have been
+ * used to compute single precise scalar.
+ *
+ * The approach of starting with precise=true for all registers and then
+ * backtrack to mark a register as not precise when the verifier detects
+ * that program doesn't care about specific value (e.g., when helper
+ * takes register as ARG_ANYTHING parameter) is not safe.
+ *
+ * It's ok to walk single parentage chain of the verifier states.
+ * It's possible that this backtracking will go all the way till 1st insn.
+ * All other branches will be explored for needing precision later.
+ *
+ * The backtracking needs to deal with cases like:
+ *   R8=map_value(id=0,off=0,ks=4,vs=1952,imm=0) R9_w=map_value(id=0,off=40,ks=4,vs=1952,imm=0)
+ * r9 -= r8
+ * r5 = r9
+ * if r5 > 0x79f goto pc+7
+ *    R5_w=inv(id=0,umax_value=1951,var_off=(0x0; 0x7ff))
+ * r5 += 1
+ * ...
+ * call bpf_perf_event_output#25
+ *   where .arg5_type = ARG_CONST_SIZE_OR_ZERO
+ *
+ * and this case:
+ * r6 = 1
+ * call foo // uses callee's r6 inside to compute r0
+ * r0 += r6
+ * if r0 == 0 goto
+ *
+ * to track above reg_mask/stack_mask needs to be independent for each frame.
+ *
+ * Also if parent's curframe > frame where backtracking started,
+ * the verifier need to mark registers in both frames, otherwise callees
+ * may incorrectly prune callers. This is similar to
+ * commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences")
+ *
+ * For now backtracking falls back into conservative marking.
+ */
+static void mark_all_scalars_precise(struct bpf_verifier_env *env,
+				     struct bpf_verifier_state *st)
+{
+	struct bpf_func_state *func;
+	struct bpf_reg_state *reg;
+	int i, j;
+
+	/* big hammer: mark all scalars precise in this path.
+	 * pop_stack may still get !precise scalars.
+	 * We also skip current state and go straight to first parent state,
+	 * because precision markings in current non-checkpointed state are
+	 * not needed. See why in the comment in __mark_chain_precision below.
+	 */
+	for (st = st->parent; st; st = st->parent) {
+		for (i = 0; i <= st->curframe; i++) {
+			func = st->frame[i];
+			for (j = 0; j < BPF_REG_FP; j++) {
+				reg = &func->regs[j];
+				if (reg->type != SCALAR_VALUE)
+					continue;
+				reg->precise = true;
+			}
+			for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) {
+				if (!is_spilled_reg(&func->stack[j]))
+					continue;
+				reg = &func->stack[j].spilled_ptr;
+				if (reg->type != SCALAR_VALUE)
+					continue;
+				reg->precise = true;
+			}
+		}
+	}
+}
+
+static void mark_all_scalars_imprecise(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
+{
+	struct bpf_func_state *func;
+	struct bpf_reg_state *reg;
+	int i, j;
+
+	for (i = 0; i <= st->curframe; i++) {
+		func = st->frame[i];
+		for (j = 0; j < BPF_REG_FP; j++) {
+			reg = &func->regs[j];
+			if (reg->type != SCALAR_VALUE)
+				continue;
+			reg->precise = false;
+		}
+		for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) {
+			if (!is_spilled_reg(&func->stack[j]))
+				continue;
+			reg = &func->stack[j].spilled_ptr;
+			if (reg->type != SCALAR_VALUE)
+				continue;
+			reg->precise = false;
+		}
+	}
+}
+
+/*
+ * __mark_chain_precision() backtracks BPF program instruction sequence and
+ * chain of verifier states making sure that register *regno* (if regno >= 0)
+ * and/or stack slot *spi* (if spi >= 0) are marked as precisely tracked
+ * SCALARS, as well as any other registers and slots that contribute to
+ * a tracked state of given registers/stack slots, depending on specific BPF
+ * assembly instructions (see backtrack_insns() for exact instruction handling
+ * logic). This backtracking relies on recorded jmp_history and is able to
+ * traverse entire chain of parent states. This process ends only when all the
+ * necessary registers/slots and their transitive dependencies are marked as
+ * precise.
+ *
+ * One important and subtle aspect is that precise marks *do not matter* in
+ * the currently verified state (current state). It is important to understand
+ * why this is the case.
+ *
+ * First, note that current state is the state that is not yet "checkpointed",
+ * i.e., it is not yet put into env->explored_states, and it has no children
+ * states as well. It's ephemeral, and can end up either a) being discarded if
+ * compatible explored state is found at some point or BPF_EXIT instruction is
+ * reached or b) checkpointed and put into env->explored_states, branching out
+ * into one or more children states.
+ *
+ * In the former case, precise markings in current state are completely
+ * ignored by state comparison code (see regsafe() for details). Only
+ * checkpointed ("old") state precise markings are important, and if old
+ * state's register/slot is precise, regsafe() assumes current state's
+ * register/slot as precise and checks value ranges exactly and precisely. If
+ * states turn out to be compatible, current state's necessary precise
+ * markings and any required parent states' precise markings are enforced
+ * after the fact with propagate_precision() logic, after the fact. But it's
+ * important to realize that in this case, even after marking current state
+ * registers/slots as precise, we immediately discard current state. So what
+ * actually matters is any of the precise markings propagated into current
+ * state's parent states, which are always checkpointed (due to b) case above).
+ * As such, for scenario a) it doesn't matter if current state has precise
+ * markings set or not.
+ *
+ * Now, for the scenario b), checkpointing and forking into child(ren)
+ * state(s). Note that before current state gets to checkpointing step, any
+ * processed instruction always assumes precise SCALAR register/slot
+ * knowledge: if precise value or range is useful to prune jump branch, BPF
+ * verifier takes this opportunity enthusiastically. Similarly, when
+ * register's value is used to calculate offset or memory address, exact
+ * knowledge of SCALAR range is assumed, checked, and enforced. So, similar to
+ * what we mentioned above about state comparison ignoring precise markings
+ * during state comparison, BPF verifier ignores and also assumes precise
+ * markings *at will* during instruction verification process. But as verifier
+ * assumes precision, it also propagates any precision dependencies across
+ * parent states, which are not yet finalized, so can be further restricted
+ * based on new knowledge gained from restrictions enforced by their children
+ * states. This is so that once those parent states are finalized, i.e., when
+ * they have no more active children state, state comparison logic in
+ * is_state_visited() would enforce strict and precise SCALAR ranges, if
+ * required for correctness.
+ *
+ * To build a bit more intuition, note also that once a state is checkpointed,
+ * the path we took to get to that state is not important. This is crucial
+ * property for state pruning. When state is checkpointed and finalized at
+ * some instruction index, it can be correctly and safely used to "short
+ * circuit" any *compatible* state that reaches exactly the same instruction
+ * index. I.e., if we jumped to that instruction from a completely different
+ * code path than original finalized state was derived from, it doesn't
+ * matter, current state can be discarded because from that instruction
+ * forward having a compatible state will ensure we will safely reach the
+ * exit. States describe preconditions for further exploration, but completely
+ * forget the history of how we got here.
+ *
+ * This also means that even if we needed precise SCALAR range to get to
+ * finalized state, but from that point forward *that same* SCALAR register is
+ * never used in a precise context (i.e., it's precise value is not needed for
+ * correctness), it's correct and safe to mark such register as "imprecise"
+ * (i.e., precise marking set to false). This is what we rely on when we do
+ * not set precise marking in current state. If no child state requires
+ * precision for any given SCALAR register, it's safe to dictate that it can
+ * be imprecise. If any child state does require this register to be precise,
+ * we'll mark it precise later retroactively during precise markings
+ * propagation from child state to parent states.
+ *
+ * Skipping precise marking setting in current state is a mild version of
+ * relying on the above observation. But we can utilize this property even
+ * more aggressively by proactively forgetting any precise marking in the
+ * current state (which we inherited from the parent state), right before we
+ * checkpoint it and branch off into new child state. This is done by
+ * mark_all_scalars_imprecise() to hopefully get more permissive and generic
+ * finalized states which help in short circuiting more future states.
+ */
+static int __mark_chain_precision(struct bpf_verifier_env *env, int frame, int regno,
+				  int spi)
+{
+	struct bpf_verifier_state *st = env->cur_state;
+	int first_idx = st->first_insn_idx;
+	int last_idx = env->insn_idx;
+	struct bpf_func_state *func;
+	struct bpf_reg_state *reg;
+	u32 reg_mask = regno >= 0 ? 1u << regno : 0;
+	u64 stack_mask = spi >= 0 ? 1ull << spi : 0;
+	bool skip_first = true;
+	bool new_marks = false;
+	int i, err;
+
+	if (!env->bpf_capable)
+		return 0;
+
+	/* Do sanity checks against current state of register and/or stack
+	 * slot, but don't set precise flag in current state, as precision
+	 * tracking in the current state is unnecessary.
+	 */
+	func = st->frame[frame];
+	if (regno >= 0) {
+		reg = &func->regs[regno];
+		if (reg->type != SCALAR_VALUE) {
+			WARN_ONCE(1, "backtracing misuse");
+			return -EFAULT;
+		}
+		new_marks = true;
+	}
+
+	while (spi >= 0) {
+		if (!is_spilled_reg(&func->stack[spi])) {
+			stack_mask = 0;
+			break;
+		}
+		reg = &func->stack[spi].spilled_ptr;
+		if (reg->type != SCALAR_VALUE) {
+			stack_mask = 0;
+			break;
+		}
+		new_marks = true;
+		break;
+	}
+
+	if (!new_marks)
+		return 0;
+	if (!reg_mask && !stack_mask)
+		return 0;
+
+	for (;;) {
+		DECLARE_BITMAP(mask, 64);
+		u32 history = st->jmp_history_cnt;
+
+		if (env->log.level & BPF_LOG_LEVEL2)
+			verbose(env, "last_idx %d first_idx %d\n", last_idx, first_idx);
+
+		if (last_idx < 0) {
+			/* we are at the entry into subprog, which
+			 * is expected for global funcs, but only if
+			 * requested precise registers are R1-R5
+			 * (which are global func's input arguments)
+			 */
+			if (st->curframe == 0 &&
+			    st->frame[0]->subprogno > 0 &&
+			    st->frame[0]->callsite == BPF_MAIN_FUNC &&
+			    stack_mask == 0 && (reg_mask & ~0x3e) == 0) {
+				bitmap_from_u64(mask, reg_mask);
+				for_each_set_bit(i, mask, 32) {
+					reg = &st->frame[0]->regs[i];
+					if (reg->type != SCALAR_VALUE) {
+						reg_mask &= ~(1u << i);
+						continue;
+					}
+					reg->precise = true;
+				}
+				return 0;
+			}
+
+			verbose(env, "BUG backtracing func entry subprog %d reg_mask %x stack_mask %llx\n",
+				st->frame[0]->subprogno, reg_mask, stack_mask);
+			WARN_ONCE(1, "verifier backtracking bug");
+			return -EFAULT;
+		}
+
+		for (i = last_idx;;) {
+			if (skip_first) {
+				err = 0;
+				skip_first = false;
+			} else {
+				err = backtrack_insn(env, i, &reg_mask, &stack_mask);
+			}
+			if (err == -ENOTSUPP) {
+				mark_all_scalars_precise(env, st);
+				return 0;
+			} else if (err) {
+				return err;
+			}
+			if (!reg_mask && !stack_mask)
+				/* Found assignment(s) into tracked register in this state.
+				 * Since this state is already marked, just return.
+				 * Nothing to be tracked further in the parent state.
+				 */
+				return 0;
+			i = get_prev_insn_idx(st, i, &history);
+			if (i == -ENOENT)
+				break;
+			if (i >= env->prog->len) {
+				/* This can happen if backtracking reached insn 0
+				 * and there are still reg_mask or stack_mask
+				 * to backtrack.
+				 * It means the backtracking missed the spot where
+				 * particular register was initialized with a constant.
+				 */
+				verbose(env, "BUG backtracking idx %d\n", i);
+				WARN_ONCE(1, "verifier backtracking bug");
+				return -EFAULT;
+			}
+		}
+		st = st->parent;
+		if (!st)
+			break;
+
+		new_marks = false;
+		func = st->frame[frame];
+		bitmap_from_u64(mask, reg_mask);
+		for_each_set_bit(i, mask, 32) {
+			reg = &func->regs[i];
+			if (reg->type != SCALAR_VALUE) {
+				reg_mask &= ~(1u << i);
+				continue;
+			}
+			if (!reg->precise)
+				new_marks = true;
+			reg->precise = true;
+		}
+
+		bitmap_from_u64(mask, stack_mask);
+		for_each_set_bit(i, mask, 64) {
+			if (i >= func->allocated_stack / BPF_REG_SIZE) {
+				/* the sequence of instructions:
+				 * 2: (bf) r3 = r10
+				 * 3: (7b) *(u64 *)(r3 -8) = r0
+				 * 4: (79) r4 = *(u64 *)(r10 -8)
+				 * doesn't contain jmps. It's backtracked
+				 * as a single block.
+				 * During backtracking insn 3 is not recognized as
+				 * stack access, so at the end of backtracking
+				 * stack slot fp-8 is still marked in stack_mask.
+				 * However the parent state may not have accessed
+				 * fp-8 and it's "unallocated" stack space.
+				 * In such case fallback to conservative.
+				 */
+				mark_all_scalars_precise(env, st);
+				return 0;
+			}
+
+			if (!is_spilled_reg(&func->stack[i])) {
+				stack_mask &= ~(1ull << i);
+				continue;
+			}
+			reg = &func->stack[i].spilled_ptr;
+			if (reg->type != SCALAR_VALUE) {
+				stack_mask &= ~(1ull << i);
+				continue;
+			}
+			if (!reg->precise)
+				new_marks = true;
+			reg->precise = true;
+		}
+		if (env->log.level & BPF_LOG_LEVEL2) {
+			verbose(env, "parent %s regs=%x stack=%llx marks:",
+				new_marks ? "didn't have" : "already had",
+				reg_mask, stack_mask);
+			print_verifier_state(env, func, true);
+		}
+
+		if (!reg_mask && !stack_mask)
+			break;
+		if (!new_marks)
+			break;
+
+		last_idx = st->last_insn_idx;
+		first_idx = st->first_insn_idx;
+	}
+	return 0;
+}
+
+int mark_chain_precision(struct bpf_verifier_env *env, int regno)
+{
+	return __mark_chain_precision(env, env->cur_state->curframe, regno, -1);
+}
+
+static int mark_chain_precision_frame(struct bpf_verifier_env *env, int frame, int regno)
+{
+	return __mark_chain_precision(env, frame, regno, -1);
+}
+
+static int mark_chain_precision_stack_frame(struct bpf_verifier_env *env, int frame, int spi)
+{
+	return __mark_chain_precision(env, frame, -1, spi);
+}
+
+static bool is_spillable_regtype(enum bpf_reg_type type)
+{
+	switch (base_type(type)) {
+	case PTR_TO_MAP_VALUE:
+	case PTR_TO_STACK:
+	case PTR_TO_CTX:
+	case PTR_TO_PACKET:
+	case PTR_TO_PACKET_META:
+	case PTR_TO_PACKET_END:
+	case PTR_TO_FLOW_KEYS:
+	case CONST_PTR_TO_MAP:
+	case PTR_TO_SOCKET:
+	case PTR_TO_SOCK_COMMON:
+	case PTR_TO_TCP_SOCK:
+	case PTR_TO_XDP_SOCK:
+	case PTR_TO_BTF_ID:
+	case PTR_TO_BUF:
+	case PTR_TO_MEM:
+	case PTR_TO_FUNC:
+	case PTR_TO_MAP_KEY:
+		return true;
+	default:
+		return false;
+	}
+}
+
+/* Does this register contain a constant zero? */
+static bool register_is_null(struct bpf_reg_state *reg)
+{
+	return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0);
+}
+
+static bool register_is_const(struct bpf_reg_state *reg)
+{
+	return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off);
+}
+
+static bool __is_scalar_unbounded(struct bpf_reg_state *reg)
+{
+	return tnum_is_unknown(reg->var_off) &&
+	       reg->smin_value == S64_MIN && reg->smax_value == S64_MAX &&
+	       reg->umin_value == 0 && reg->umax_value == U64_MAX &&
+	       reg->s32_min_value == S32_MIN && reg->s32_max_value == S32_MAX &&
+	       reg->u32_min_value == 0 && reg->u32_max_value == U32_MAX;
+}
+
+static bool register_is_bounded(struct bpf_reg_state *reg)
+{
+	return reg->type == SCALAR_VALUE && !__is_scalar_unbounded(reg);
+}
+
+static bool __is_pointer_value(bool allow_ptr_leaks,
+			       const struct bpf_reg_state *reg)
+{
+	if (allow_ptr_leaks)
+		return false;
+
+	return reg->type != SCALAR_VALUE;
+}
+
+/* Copy src state preserving dst->parent and dst->live fields */
+static void copy_register_state(struct bpf_reg_state *dst, const struct bpf_reg_state *src)
+{
+	struct bpf_reg_state *parent = dst->parent;
+	enum bpf_reg_liveness live = dst->live;
+
+	*dst = *src;
+	dst->parent = parent;
+	dst->live = live;
+}
+
+static void save_register_state(struct bpf_func_state *state,
+				int spi, struct bpf_reg_state *reg,
+				int size)
+{
+	int i;
+
+	copy_register_state(&state->stack[spi].spilled_ptr, reg);
+	if (size == BPF_REG_SIZE)
+		state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+
+	for (i = BPF_REG_SIZE; i > BPF_REG_SIZE - size; i--)
+		state->stack[spi].slot_type[i - 1] = STACK_SPILL;
+
+	/* size < 8 bytes spill */
+	for (; i; i--)
+		scrub_spilled_slot(&state->stack[spi].slot_type[i - 1]);
+}
+
+static bool is_bpf_st_mem(struct bpf_insn *insn)
+{
+	return BPF_CLASS(insn->code) == BPF_ST && BPF_MODE(insn->code) == BPF_MEM;
+}
+
+/* check_stack_{read,write}_fixed_off functions track spill/fill of registers,
+ * stack boundary and alignment are checked in check_mem_access()
+ */
+static int check_stack_write_fixed_off(struct bpf_verifier_env *env,
+				       /* stack frame we're writing to */
+				       struct bpf_func_state *state,
+				       int off, int size, int value_regno,
+				       int insn_idx)
+{
+	struct bpf_func_state *cur; /* state of the current function */
+	int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err;
+	struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
+	struct bpf_reg_state *reg = NULL;
+	u32 dst_reg = insn->dst_reg;
+
+	err = grow_stack_state(state, round_up(slot + 1, BPF_REG_SIZE));
+	if (err)
+		return err;
+	/* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
+	 * so it's aligned access and [off, off + size) are within stack limits
+	 */
+	if (!env->allow_ptr_leaks &&
+	    is_spilled_reg(&state->stack[spi]) &&
+	    size != BPF_REG_SIZE) {
+		verbose(env, "attempt to corrupt spilled pointer on stack\n");
+		return -EACCES;
+	}
+
+	cur = env->cur_state->frame[env->cur_state->curframe];
+	if (value_regno >= 0)
+		reg = &cur->regs[value_regno];
+	if (!env->bypass_spec_v4) {
+		bool sanitize = reg && is_spillable_regtype(reg->type);
+
+		for (i = 0; i < size; i++) {
+			u8 type = state->stack[spi].slot_type[i];
+
+			if (type != STACK_MISC && type != STACK_ZERO) {
+				sanitize = true;
+				break;
+			}
+		}
+
+		if (sanitize)
+			env->insn_aux_data[insn_idx].sanitize_stack_spill = true;
+	}
+
+	mark_stack_slot_scratched(env, spi);
+	if (reg && !(off % BPF_REG_SIZE) && register_is_bounded(reg) &&
+	    !register_is_null(reg) && env->bpf_capable) {
+		if (dst_reg != BPF_REG_FP) {
+			/* The backtracking logic can only recognize explicit
+			 * stack slot address like [fp - 8]. Other spill of
+			 * scalar via different register has to be conservative.
+			 * Backtrack from here and mark all registers as precise
+			 * that contributed into 'reg' being a constant.
+			 */
+			err = mark_chain_precision(env, value_regno);
+			if (err)
+				return err;
+		}
+		save_register_state(state, spi, reg, size);
+		/* Break the relation on a narrowing spill. */
+		if (fls64(reg->umax_value) > BITS_PER_BYTE * size)
+			state->stack[spi].spilled_ptr.id = 0;
+	} else if (!reg && !(off % BPF_REG_SIZE) && is_bpf_st_mem(insn) &&
+		   insn->imm != 0 && env->bpf_capable) {
+		struct bpf_reg_state fake_reg = {};
+
+		__mark_reg_known(&fake_reg, insn->imm);
+		fake_reg.type = SCALAR_VALUE;
+		save_register_state(state, spi, &fake_reg, size);
+	} else if (reg && is_spillable_regtype(reg->type)) {
+		/* register containing pointer is being spilled into stack */
+		if (size != BPF_REG_SIZE) {
+			verbose_linfo(env, insn_idx, "; ");
+			verbose(env, "invalid size of register spill\n");
+			return -EACCES;
+		}
+		if (state != cur && reg->type == PTR_TO_STACK) {
+			verbose(env, "cannot spill pointers to stack into stack frame of the caller\n");
+			return -EINVAL;
+		}
+		save_register_state(state, spi, reg, size);
+	} else {
+		u8 type = STACK_MISC;
+
+		/* regular write of data into stack destroys any spilled ptr */
+		state->stack[spi].spilled_ptr.type = NOT_INIT;
+		/* Mark slots as STACK_MISC if they belonged to spilled ptr. */
+		if (is_spilled_reg(&state->stack[spi]))
+			for (i = 0; i < BPF_REG_SIZE; i++)
+				scrub_spilled_slot(&state->stack[spi].slot_type[i]);
+
+		/* only mark the slot as written if all 8 bytes were written
+		 * otherwise read propagation may incorrectly stop too soon
+		 * when stack slots are partially written.
+		 * This heuristic means that read propagation will be
+		 * conservative, since it will add reg_live_read marks
+		 * to stack slots all the way to first state when programs
+		 * writes+reads less than 8 bytes
+		 */
+		if (size == BPF_REG_SIZE)
+			state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+
+		/* when we zero initialize stack slots mark them as such */
+		if ((reg && register_is_null(reg)) ||
+		    (!reg && is_bpf_st_mem(insn) && insn->imm == 0)) {
+			/* backtracking doesn't work for STACK_ZERO yet. */
+			err = mark_chain_precision(env, value_regno);
+			if (err)
+				return err;
+			type = STACK_ZERO;
+		}
+
+		/* Mark slots affected by this stack write. */
+		for (i = 0; i < size; i++)
+			state->stack[spi].slot_type[(slot - i) % BPF_REG_SIZE] =
+				type;
+	}
+	return 0;
+}
+
+/* Write the stack: 'stack[ptr_regno + off] = value_regno'. 'ptr_regno' is
+ * known to contain a variable offset.
+ * This function checks whether the write is permitted and conservatively
+ * tracks the effects of the write, considering that each stack slot in the
+ * dynamic range is potentially written to.
+ *
+ * 'off' includes 'regno->off'.
+ * 'value_regno' can be -1, meaning that an unknown value is being written to
+ * the stack.
+ *
+ * Spilled pointers in range are not marked as written because we don't know
+ * what's going to be actually written. This means that read propagation for
+ * future reads cannot be terminated by this write.
+ *
+ * For privileged programs, uninitialized stack slots are considered
+ * initialized by this write (even though we don't know exactly what offsets
+ * are going to be written to). The idea is that we don't want the verifier to
+ * reject future reads that access slots written to through variable offsets.
+ */
+static int check_stack_write_var_off(struct bpf_verifier_env *env,
+				     /* func where register points to */
+				     struct bpf_func_state *state,
+				     int ptr_regno, int off, int size,
+				     int value_regno, int insn_idx)
+{
+	struct bpf_func_state *cur; /* state of the current function */
+	int min_off, max_off;
+	int i, err;
+	struct bpf_reg_state *ptr_reg = NULL, *value_reg = NULL;
+	bool writing_zero = false;
+	/* set if the fact that we're writing a zero is used to let any
+	 * stack slots remain STACK_ZERO
+	 */
+	bool zero_used = false;
+
+	cur = env->cur_state->frame[env->cur_state->curframe];
+	ptr_reg = &cur->regs[ptr_regno];
+	min_off = ptr_reg->smin_value + off;
+	max_off = ptr_reg->smax_value + off + size;
+	if (value_regno >= 0)
+		value_reg = &cur->regs[value_regno];
+	if (value_reg && register_is_null(value_reg))
+		writing_zero = true;
+
+	err = grow_stack_state(state, round_up(-min_off, BPF_REG_SIZE));
+	if (err)
+		return err;
+
+
+	/* Variable offset writes destroy any spilled pointers in range. */
+	for (i = min_off; i < max_off; i++) {
+		u8 new_type, *stype;
+		int slot, spi;
+
+		slot = -i - 1;
+		spi = slot / BPF_REG_SIZE;
+		stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
+		mark_stack_slot_scratched(env, spi);
+
+		if (!env->allow_ptr_leaks && *stype != STACK_MISC && *stype != STACK_ZERO) {
+			/* Reject the write if range we may write to has not
+			 * been initialized beforehand. If we didn't reject
+			 * here, the ptr status would be erased below (even
+			 * though not all slots are actually overwritten),
+			 * possibly opening the door to leaks.
+			 *
+			 * We do however catch STACK_INVALID case below, and
+			 * only allow reading possibly uninitialized memory
+			 * later for CAP_PERFMON, as the write may not happen to
+			 * that slot.
+			 */
+			verbose(env, "spilled ptr in range of var-offset stack write; insn %d, ptr off: %d",
+				insn_idx, i);
+			return -EINVAL;
+		}
+
+		/* Erase all spilled pointers. */
+		state->stack[spi].spilled_ptr.type = NOT_INIT;
+
+		/* Update the slot type. */
+		new_type = STACK_MISC;
+		if (writing_zero && *stype == STACK_ZERO) {
+			new_type = STACK_ZERO;
+			zero_used = true;
+		}
+		/* If the slot is STACK_INVALID, we check whether it's OK to
+		 * pretend that it will be initialized by this write. The slot
+		 * might not actually be written to, and so if we mark it as
+		 * initialized future reads might leak uninitialized memory.
+		 * For privileged programs, we will accept such reads to slots
+		 * that may or may not be written because, if we're reject
+		 * them, the error would be too confusing.
+		 */
+		if (*stype == STACK_INVALID && !env->allow_uninit_stack) {
+			verbose(env, "uninit stack in range of var-offset write prohibited for !root; insn %d, off: %d",
+					insn_idx, i);
+			return -EINVAL;
+		}
+		*stype = new_type;
+	}
+	if (zero_used) {
+		/* backtracking doesn't work for STACK_ZERO yet. */
+		err = mark_chain_precision(env, value_regno);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+/* When register 'dst_regno' is assigned some values from stack[min_off,
+ * max_off), we set the register's type according to the types of the
+ * respective stack slots. If all the stack values are known to be zeros, then
+ * so is the destination reg. Otherwise, the register is considered to be
+ * SCALAR. This function does not deal with register filling; the caller must
+ * ensure that all spilled registers in the stack range have been marked as
+ * read.
+ */
+static void mark_reg_stack_read(struct bpf_verifier_env *env,
+				/* func where src register points to */
+				struct bpf_func_state *ptr_state,
+				int min_off, int max_off, int dst_regno)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	int i, slot, spi;
+	u8 *stype;
+	int zeros = 0;
+
+	for (i = min_off; i < max_off; i++) {
+		slot = -i - 1;
+		spi = slot / BPF_REG_SIZE;
+		stype = ptr_state->stack[spi].slot_type;
+		if (stype[slot % BPF_REG_SIZE] != STACK_ZERO)
+			break;
+		zeros++;
+	}
+	if (zeros == max_off - min_off) {
+		/* any access_size read into register is zero extended,
+		 * so the whole register == const_zero
+		 */
+		__mark_reg_const_zero(&state->regs[dst_regno]);
+		/* backtracking doesn't support STACK_ZERO yet,
+		 * so mark it precise here, so that later
+		 * backtracking can stop here.
+		 * Backtracking may not need this if this register
+		 * doesn't participate in pointer adjustment.
+		 * Forward propagation of precise flag is not
+		 * necessary either. This mark is only to stop
+		 * backtracking. Any register that contributed
+		 * to const 0 was marked precise before spill.
+		 */
+		state->regs[dst_regno].precise = true;
+	} else {
+		/* have read misc data from the stack */
+		mark_reg_unknown(env, state->regs, dst_regno);
+	}
+	state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
+}
+
+/* Read the stack at 'off' and put the results into the register indicated by
+ * 'dst_regno'. It handles reg filling if the addressed stack slot is a
+ * spilled reg.
+ *
+ * 'dst_regno' can be -1, meaning that the read value is not going to a
+ * register.
+ *
+ * The access is assumed to be within the current stack bounds.
+ */
+static int check_stack_read_fixed_off(struct bpf_verifier_env *env,
+				      /* func where src register points to */
+				      struct bpf_func_state *reg_state,
+				      int off, int size, int dst_regno)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	int i, slot = -off - 1, spi = slot / BPF_REG_SIZE;
+	struct bpf_reg_state *reg;
+	u8 *stype, type;
+
+	stype = reg_state->stack[spi].slot_type;
+	reg = &reg_state->stack[spi].spilled_ptr;
+
+	if (is_spilled_reg(&reg_state->stack[spi])) {
+		u8 spill_size = 1;
+
+		for (i = BPF_REG_SIZE - 1; i > 0 && stype[i - 1] == STACK_SPILL; i--)
+			spill_size++;
+
+		if (size != BPF_REG_SIZE || spill_size != BPF_REG_SIZE) {
+			if (reg->type != SCALAR_VALUE) {
+				verbose_linfo(env, env->insn_idx, "; ");
+				verbose(env, "invalid size of register fill\n");
+				return -EACCES;
+			}
+
+			mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+			if (dst_regno < 0)
+				return 0;
+
+			if (!(off % BPF_REG_SIZE) && size == spill_size) {
+				/* The earlier check_reg_arg() has decided the
+				 * subreg_def for this insn.  Save it first.
+				 */
+				s32 subreg_def = state->regs[dst_regno].subreg_def;
+
+				copy_register_state(&state->regs[dst_regno], reg);
+				state->regs[dst_regno].subreg_def = subreg_def;
+			} else {
+				for (i = 0; i < size; i++) {
+					type = stype[(slot - i) % BPF_REG_SIZE];
+					if (type == STACK_SPILL)
+						continue;
+					if (type == STACK_MISC)
+						continue;
+					verbose(env, "invalid read from stack off %d+%d size %d\n",
+						off, i, size);
+					return -EACCES;
+				}
+				mark_reg_unknown(env, state->regs, dst_regno);
+			}
+			state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
+			return 0;
+		}
+
+		if (dst_regno >= 0) {
+			/* restore register state from stack */
+			copy_register_state(&state->regs[dst_regno], reg);
+			/* mark reg as written since spilled pointer state likely
+			 * has its liveness marks cleared by is_state_visited()
+			 * which resets stack/reg liveness for state transitions
+			 */
+			state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
+		} else if (__is_pointer_value(env->allow_ptr_leaks, reg)) {
+			/* If dst_regno==-1, the caller is asking us whether
+			 * it is acceptable to use this value as a SCALAR_VALUE
+			 * (e.g. for XADD).
+			 * We must not allow unprivileged callers to do that
+			 * with spilled pointers.
+			 */
+			verbose(env, "leaking pointer from stack off %d\n",
+				off);
+			return -EACCES;
+		}
+		mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+	} else {
+		for (i = 0; i < size; i++) {
+			type = stype[(slot - i) % BPF_REG_SIZE];
+			if (type == STACK_MISC)
+				continue;
+			if (type == STACK_ZERO)
+				continue;
+			verbose(env, "invalid read from stack off %d+%d size %d\n",
+				off, i, size);
+			return -EACCES;
+		}
+		mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+		if (dst_regno >= 0)
+			mark_reg_stack_read(env, reg_state, off, off + size, dst_regno);
+	}
+	return 0;
+}
+
+enum bpf_access_src {
+	ACCESS_DIRECT = 1,  /* the access is performed by an instruction */
+	ACCESS_HELPER = 2,  /* the access is performed by a helper */
+};
+
+static int check_stack_range_initialized(struct bpf_verifier_env *env,
+					 int regno, int off, int access_size,
+					 bool zero_size_allowed,
+					 enum bpf_access_src type,
+					 struct bpf_call_arg_meta *meta);
+
+static struct bpf_reg_state *reg_state(struct bpf_verifier_env *env, int regno)
+{
+	return cur_regs(env) + regno;
+}
+
+/* Read the stack at 'ptr_regno + off' and put the result into the register
+ * 'dst_regno'.
+ * 'off' includes the pointer register's fixed offset(i.e. 'ptr_regno.off'),
+ * but not its variable offset.
+ * 'size' is assumed to be <= reg size and the access is assumed to be aligned.
+ *
+ * As opposed to check_stack_read_fixed_off, this function doesn't deal with
+ * filling registers (i.e. reads of spilled register cannot be detected when
+ * the offset is not fixed). We conservatively mark 'dst_regno' as containing
+ * SCALAR_VALUE. That's why we assert that the 'ptr_regno' has a variable
+ * offset; for a fixed offset check_stack_read_fixed_off should be used
+ * instead.
+ */
+static int check_stack_read_var_off(struct bpf_verifier_env *env,
+				    int ptr_regno, int off, int size, int dst_regno)
+{
+	/* The state of the source register. */
+	struct bpf_reg_state *reg = reg_state(env, ptr_regno);
+	struct bpf_func_state *ptr_state = func(env, reg);
+	int err;
+	int min_off, max_off;
+
+	/* Note that we pass a NULL meta, so raw access will not be permitted.
+	 */
+	err = check_stack_range_initialized(env, ptr_regno, off, size,
+					    false, ACCESS_DIRECT, NULL);
+	if (err)
+		return err;
+
+	min_off = reg->smin_value + off;
+	max_off = reg->smax_value + off;
+	mark_reg_stack_read(env, ptr_state, min_off, max_off + size, dst_regno);
+	return 0;
+}
+
+/* check_stack_read dispatches to check_stack_read_fixed_off or
+ * check_stack_read_var_off.
+ *
+ * The caller must ensure that the offset falls within the allocated stack
+ * bounds.
+ *
+ * 'dst_regno' is a register which will receive the value from the stack. It
+ * can be -1, meaning that the read value is not going to a register.
+ */
+static int check_stack_read(struct bpf_verifier_env *env,
+			    int ptr_regno, int off, int size,
+			    int dst_regno)
+{
+	struct bpf_reg_state *reg = reg_state(env, ptr_regno);
+	struct bpf_func_state *state = func(env, reg);
+	int err;
+	/* Some accesses are only permitted with a static offset. */
+	bool var_off = !tnum_is_const(reg->var_off);
+
+	/* The offset is required to be static when reads don't go to a
+	 * register, in order to not leak pointers (see
+	 * check_stack_read_fixed_off).
+	 */
+	if (dst_regno < 0 && var_off) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env, "variable offset stack pointer cannot be passed into helper function; var_off=%s off=%d size=%d\n",
+			tn_buf, off, size);
+		return -EACCES;
+	}
+	/* Variable offset is prohibited for unprivileged mode for simplicity
+	 * since it requires corresponding support in Spectre masking for stack
+	 * ALU. See also retrieve_ptr_limit(). The check in
+	 * check_stack_access_for_ptr_arithmetic() called by
+	 * adjust_ptr_min_max_vals() prevents users from creating stack pointers
+	 * with variable offsets, therefore no check is required here. Further,
+	 * just checking it here would be insufficient as speculative stack
+	 * writes could still lead to unsafe speculative behaviour.
+	 */
+	if (!var_off) {
+		off += reg->var_off.value;
+		err = check_stack_read_fixed_off(env, state, off, size,
+						 dst_regno);
+	} else {
+		/* Variable offset stack reads need more conservative handling
+		 * than fixed offset ones. Note that dst_regno >= 0 on this
+		 * branch.
+		 */
+		err = check_stack_read_var_off(env, ptr_regno, off, size,
+					       dst_regno);
+	}
+	return err;
+}
+
+
+/* check_stack_write dispatches to check_stack_write_fixed_off or
+ * check_stack_write_var_off.
+ *
+ * 'ptr_regno' is the register used as a pointer into the stack.
+ * 'off' includes 'ptr_regno->off', but not its variable offset (if any).
+ * 'value_regno' is the register whose value we're writing to the stack. It can
+ * be -1, meaning that we're not writing from a register.
+ *
+ * The caller must ensure that the offset falls within the maximum stack size.
+ */
+static int check_stack_write(struct bpf_verifier_env *env,
+			     int ptr_regno, int off, int size,
+			     int value_regno, int insn_idx)
+{
+	struct bpf_reg_state *reg = reg_state(env, ptr_regno);
+	struct bpf_func_state *state = func(env, reg);
+	int err;
+
+	if (tnum_is_const(reg->var_off)) {
+		off += reg->var_off.value;
+		err = check_stack_write_fixed_off(env, state, off, size,
+						  value_regno, insn_idx);
+	} else {
+		/* Variable offset stack reads need more conservative handling
+		 * than fixed offset ones.
+		 */
+		err = check_stack_write_var_off(env, state,
+						ptr_regno, off, size,
+						value_regno, insn_idx);
+	}
+	return err;
+}
+
+static int check_map_access_type(struct bpf_verifier_env *env, u32 regno,
+				 int off, int size, enum bpf_access_type type)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_map *map = regs[regno].map_ptr;
+	u32 cap = bpf_map_flags_to_cap(map);
+
+	if (type == BPF_WRITE && !(cap & BPF_MAP_CAN_WRITE)) {
+		verbose(env, "write into map forbidden, value_size=%d off=%d size=%d\n",
+			map->value_size, off, size);
+		return -EACCES;
+	}
+
+	if (type == BPF_READ && !(cap & BPF_MAP_CAN_READ)) {
+		verbose(env, "read from map forbidden, value_size=%d off=%d size=%d\n",
+			map->value_size, off, size);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+/* check read/write into memory region (e.g., map value, ringbuf sample, etc) */
+static int __check_mem_access(struct bpf_verifier_env *env, int regno,
+			      int off, int size, u32 mem_size,
+			      bool zero_size_allowed)
+{
+	bool size_ok = size > 0 || (size == 0 && zero_size_allowed);
+	struct bpf_reg_state *reg;
+
+	if (off >= 0 && size_ok && (u64)off + size <= mem_size)
+		return 0;
+
+	reg = &cur_regs(env)[regno];
+	switch (reg->type) {
+	case PTR_TO_MAP_KEY:
+		verbose(env, "invalid access to map key, key_size=%d off=%d size=%d\n",
+			mem_size, off, size);
+		break;
+	case PTR_TO_MAP_VALUE:
+		verbose(env, "invalid access to map value, value_size=%d off=%d size=%d\n",
+			mem_size, off, size);
+		break;
+	case PTR_TO_PACKET:
+	case PTR_TO_PACKET_META:
+	case PTR_TO_PACKET_END:
+		verbose(env, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
+			off, size, regno, reg->id, off, mem_size);
+		break;
+	case PTR_TO_MEM:
+	default:
+		verbose(env, "invalid access to memory, mem_size=%u off=%d size=%d\n",
+			mem_size, off, size);
+	}
+
+	return -EACCES;
+}
+
+/* check read/write into a memory region with possible variable offset */
+static int check_mem_region_access(struct bpf_verifier_env *env, u32 regno,
+				   int off, int size, u32 mem_size,
+				   bool zero_size_allowed)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_reg_state *reg = &state->regs[regno];
+	int err;
+
+	/* We may have adjusted the register pointing to memory region, so we
+	 * need to try adding each of min_value and max_value to off
+	 * to make sure our theoretical access will be safe.
+	 *
+	 * The minimum value is only important with signed
+	 * comparisons where we can't assume the floor of a
+	 * value is 0.  If we are using signed variables for our
+	 * index'es we need to make sure that whatever we use
+	 * will have a set floor within our range.
+	 */
+	if (reg->smin_value < 0 &&
+	    (reg->smin_value == S64_MIN ||
+	     (off + reg->smin_value != (s64)(s32)(off + reg->smin_value)) ||
+	      reg->smin_value + off < 0)) {
+		verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
+			regno);
+		return -EACCES;
+	}
+	err = __check_mem_access(env, regno, reg->smin_value + off, size,
+				 mem_size, zero_size_allowed);
+	if (err) {
+		verbose(env, "R%d min value is outside of the allowed memory range\n",
+			regno);
+		return err;
+	}
+
+	/* If we haven't set a max value then we need to bail since we can't be
+	 * sure we won't do bad things.
+	 * If reg->umax_value + off could overflow, treat that as unbounded too.
+	 */
+	if (reg->umax_value >= BPF_MAX_VAR_OFF) {
+		verbose(env, "R%d unbounded memory access, make sure to bounds check any such access\n",
+			regno);
+		return -EACCES;
+	}
+	err = __check_mem_access(env, regno, reg->umax_value + off, size,
+				 mem_size, zero_size_allowed);
+	if (err) {
+		verbose(env, "R%d max value is outside of the allowed memory range\n",
+			regno);
+		return err;
+	}
+
+	return 0;
+}
+
+static int __check_ptr_off_reg(struct bpf_verifier_env *env,
+			       const struct bpf_reg_state *reg, int regno,
+			       bool fixed_off_ok)
+{
+	/* Access to this pointer-typed register or passing it to a helper
+	 * is only allowed in its original, unmodified form.
+	 */
+
+	if (reg->off < 0) {
+		verbose(env, "negative offset %s ptr R%d off=%d disallowed\n",
+			reg_type_str(env, reg->type), regno, reg->off);
+		return -EACCES;
+	}
+
+	if (!fixed_off_ok && reg->off) {
+		verbose(env, "dereference of modified %s ptr R%d off=%d disallowed\n",
+			reg_type_str(env, reg->type), regno, reg->off);
+		return -EACCES;
+	}
+
+	if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env, "variable %s access var_off=%s disallowed\n",
+			reg_type_str(env, reg->type), tn_buf);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+int check_ptr_off_reg(struct bpf_verifier_env *env,
+		      const struct bpf_reg_state *reg, int regno)
+{
+	return __check_ptr_off_reg(env, reg, regno, false);
+}
+
+static int map_kptr_match_type(struct bpf_verifier_env *env,
+			       struct bpf_map_value_off_desc *off_desc,
+			       struct bpf_reg_state *reg, u32 regno)
+{
+	const char *targ_name = kernel_type_name(off_desc->kptr.btf, off_desc->kptr.btf_id);
+	int perm_flags = PTR_MAYBE_NULL;
+	const char *reg_name = "";
+
+	/* Only unreferenced case accepts untrusted pointers */
+	if (off_desc->type == BPF_KPTR_UNREF)
+		perm_flags |= PTR_UNTRUSTED;
+
+	if (base_type(reg->type) != PTR_TO_BTF_ID || (type_flag(reg->type) & ~perm_flags))
+		goto bad_type;
+
+	if (!btf_is_kernel(reg->btf)) {
+		verbose(env, "R%d must point to kernel BTF\n", regno);
+		return -EINVAL;
+	}
+	/* We need to verify reg->type and reg->btf, before accessing reg->btf */
+	reg_name = kernel_type_name(reg->btf, reg->btf_id);
+
+	/* For ref_ptr case, release function check should ensure we get one
+	 * referenced PTR_TO_BTF_ID, and that its fixed offset is 0. For the
+	 * normal store of unreferenced kptr, we must ensure var_off is zero.
+	 * Since ref_ptr cannot be accessed directly by BPF insns, checks for
+	 * reg->off and reg->ref_obj_id are not needed here.
+	 */
+	if (__check_ptr_off_reg(env, reg, regno, true))
+		return -EACCES;
+
+	/* A full type match is needed, as BTF can be vmlinux or module BTF, and
+	 * we also need to take into account the reg->off.
+	 *
+	 * We want to support cases like:
+	 *
+	 * struct foo {
+	 *         struct bar br;
+	 *         struct baz bz;
+	 * };
+	 *
+	 * struct foo *v;
+	 * v = func();	      // PTR_TO_BTF_ID
+	 * val->foo = v;      // reg->off is zero, btf and btf_id match type
+	 * val->bar = &v->br; // reg->off is still zero, but we need to retry with
+	 *                    // first member type of struct after comparison fails
+	 * val->baz = &v->bz; // reg->off is non-zero, so struct needs to be walked
+	 *                    // to match type
+	 *
+	 * In the kptr_ref case, check_func_arg_reg_off already ensures reg->off
+	 * is zero. We must also ensure that btf_struct_ids_match does not walk
+	 * the struct to match type against first member of struct, i.e. reject
+	 * second case from above. Hence, when type is BPF_KPTR_REF, we set
+	 * strict mode to true for type match.
+	 */
+	if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off,
+				  off_desc->kptr.btf, off_desc->kptr.btf_id,
+				  off_desc->type == BPF_KPTR_REF))
+		goto bad_type;
+	return 0;
+bad_type:
+	verbose(env, "invalid kptr access, R%d type=%s%s ", regno,
+		reg_type_str(env, reg->type), reg_name);
+	verbose(env, "expected=%s%s", reg_type_str(env, PTR_TO_BTF_ID), targ_name);
+	if (off_desc->type == BPF_KPTR_UNREF)
+		verbose(env, " or %s%s\n", reg_type_str(env, PTR_TO_BTF_ID | PTR_UNTRUSTED),
+			targ_name);
+	else
+		verbose(env, "\n");
+	return -EINVAL;
+}
+
+static int check_map_kptr_access(struct bpf_verifier_env *env, u32 regno,
+				 int value_regno, int insn_idx,
+				 struct bpf_map_value_off_desc *off_desc)
+{
+	struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
+	int class = BPF_CLASS(insn->code);
+	struct bpf_reg_state *val_reg;
+
+	/* Things we already checked for in check_map_access and caller:
+	 *  - Reject cases where variable offset may touch kptr
+	 *  - size of access (must be BPF_DW)
+	 *  - tnum_is_const(reg->var_off)
+	 *  - off_desc->offset == off + reg->var_off.value
+	 */
+	/* Only BPF_[LDX,STX,ST] | BPF_MEM | BPF_DW is supported */
+	if (BPF_MODE(insn->code) != BPF_MEM) {
+		verbose(env, "kptr in map can only be accessed using BPF_MEM instruction mode\n");
+		return -EACCES;
+	}
+
+	/* We only allow loading referenced kptr, since it will be marked as
+	 * untrusted, similar to unreferenced kptr.
+	 */
+	if (class != BPF_LDX && off_desc->type == BPF_KPTR_REF) {
+		verbose(env, "store to referenced kptr disallowed\n");
+		return -EACCES;
+	}
+
+	if (class == BPF_LDX) {
+		val_reg = reg_state(env, value_regno);
+		/* We can simply mark the value_regno receiving the pointer
+		 * value from map as PTR_TO_BTF_ID, with the correct type.
+		 */
+		mark_btf_ld_reg(env, cur_regs(env), value_regno, PTR_TO_BTF_ID, off_desc->kptr.btf,
+				off_desc->kptr.btf_id, PTR_MAYBE_NULL | PTR_UNTRUSTED);
+		/* For mark_ptr_or_null_reg */
+		val_reg->id = ++env->id_gen;
+	} else if (class == BPF_STX) {
+		val_reg = reg_state(env, value_regno);
+		if (!register_is_null(val_reg) &&
+		    map_kptr_match_type(env, off_desc, val_reg, value_regno))
+			return -EACCES;
+	} else if (class == BPF_ST) {
+		if (insn->imm) {
+			verbose(env, "BPF_ST imm must be 0 when storing to kptr at off=%u\n",
+				off_desc->offset);
+			return -EACCES;
+		}
+	} else {
+		verbose(env, "kptr in map can only be accessed using BPF_LDX/BPF_STX/BPF_ST\n");
+		return -EACCES;
+	}
+	return 0;
+}
+
+/* check read/write into a map element with possible variable offset */
+static int check_map_access(struct bpf_verifier_env *env, u32 regno,
+			    int off, int size, bool zero_size_allowed,
+			    enum bpf_access_src src)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_reg_state *reg = &state->regs[regno];
+	struct bpf_map *map = reg->map_ptr;
+	int err;
+
+	err = check_mem_region_access(env, regno, off, size, map->value_size,
+				      zero_size_allowed);
+	if (err)
+		return err;
+
+	if (map_value_has_spin_lock(map)) {
+		u32 lock = map->spin_lock_off;
+
+		/* if any part of struct bpf_spin_lock can be touched by
+		 * load/store reject this program.
+		 * To check that [x1, x2) overlaps with [y1, y2)
+		 * it is sufficient to check x1 < y2 && y1 < x2.
+		 */
+		if (reg->smin_value + off < lock + sizeof(struct bpf_spin_lock) &&
+		     lock < reg->umax_value + off + size) {
+			verbose(env, "bpf_spin_lock cannot be accessed directly by load/store\n");
+			return -EACCES;
+		}
+	}
+	if (map_value_has_timer(map)) {
+		u32 t = map->timer_off;
+
+		if (reg->smin_value + off < t + sizeof(struct bpf_timer) &&
+		     t < reg->umax_value + off + size) {
+			verbose(env, "bpf_timer cannot be accessed directly by load/store\n");
+			return -EACCES;
+		}
+	}
+	if (map_value_has_kptrs(map)) {
+		struct bpf_map_value_off *tab = map->kptr_off_tab;
+		int i;
+
+		for (i = 0; i < tab->nr_off; i++) {
+			u32 p = tab->off[i].offset;
+
+			if (reg->smin_value + off < p + sizeof(u64) &&
+			    p < reg->umax_value + off + size) {
+				if (src != ACCESS_DIRECT) {
+					verbose(env, "kptr cannot be accessed indirectly by helper\n");
+					return -EACCES;
+				}
+				if (!tnum_is_const(reg->var_off)) {
+					verbose(env, "kptr access cannot have variable offset\n");
+					return -EACCES;
+				}
+				if (p != off + reg->var_off.value) {
+					verbose(env, "kptr access misaligned expected=%u off=%llu\n",
+						p, off + reg->var_off.value);
+					return -EACCES;
+				}
+				if (size != bpf_size_to_bytes(BPF_DW)) {
+					verbose(env, "kptr access size must be BPF_DW\n");
+					return -EACCES;
+				}
+				break;
+			}
+		}
+	}
+	return err;
+}
+
+#define MAX_PACKET_OFF 0xffff
+
+static bool may_access_direct_pkt_data(struct bpf_verifier_env *env,
+				       const struct bpf_call_arg_meta *meta,
+				       enum bpf_access_type t)
+{
+	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
+
+	switch (prog_type) {
+	/* Program types only with direct read access go here! */
+	case BPF_PROG_TYPE_LWT_IN:
+	case BPF_PROG_TYPE_LWT_OUT:
+	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
+	case BPF_PROG_TYPE_SK_REUSEPORT:
+	case BPF_PROG_TYPE_FLOW_DISSECTOR:
+	case BPF_PROG_TYPE_CGROUP_SKB:
+		if (t == BPF_WRITE)
+			return false;
+		fallthrough;
+
+	/* Program types with direct read + write access go here! */
+	case BPF_PROG_TYPE_SCHED_CLS:
+	case BPF_PROG_TYPE_SCHED_ACT:
+	case BPF_PROG_TYPE_XDP:
+	case BPF_PROG_TYPE_LWT_XMIT:
+	case BPF_PROG_TYPE_SK_SKB:
+	case BPF_PROG_TYPE_SK_MSG:
+		if (meta)
+			return meta->pkt_access;
+
+		env->seen_direct_write = true;
+		return true;
+
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+		if (t == BPF_WRITE)
+			env->seen_direct_write = true;
+
+		return true;
+
+	default:
+		return false;
+	}
+}
+
+static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
+			       int size, bool zero_size_allowed)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *reg = &regs[regno];
+	int err;
+
+	/* We may have added a variable offset to the packet pointer; but any
+	 * reg->range we have comes after that.  We are only checking the fixed
+	 * offset.
+	 */
+
+	/* We don't allow negative numbers, because we aren't tracking enough
+	 * detail to prove they're safe.
+	 */
+	if (reg->smin_value < 0) {
+		verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
+			regno);
+		return -EACCES;
+	}
+
+	err = reg->range < 0 ? -EINVAL :
+	      __check_mem_access(env, regno, off, size, reg->range,
+				 zero_size_allowed);
+	if (err) {
+		verbose(env, "R%d offset is outside of the packet\n", regno);
+		return err;
+	}
+
+	/* __check_mem_access has made sure "off + size - 1" is within u16.
+	 * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff,
+	 * otherwise find_good_pkt_pointers would have refused to set range info
+	 * that __check_mem_access would have rejected this pkt access.
+	 * Therefore, "off + reg->umax_value + size - 1" won't overflow u32.
+	 */
+	env->prog->aux->max_pkt_offset =
+		max_t(u32, env->prog->aux->max_pkt_offset,
+		      off + reg->umax_value + size - 1);
+
+	return err;
+}
+
+/* check access to 'struct bpf_context' fields.  Supports fixed offsets only */
+static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size,
+			    enum bpf_access_type t, enum bpf_reg_type *reg_type,
+			    struct btf **btf, u32 *btf_id)
+{
+	struct bpf_insn_access_aux info = {
+		.reg_type = *reg_type,
+		.log = &env->log,
+	};
+
+	if (env->ops->is_valid_access &&
+	    env->ops->is_valid_access(off, size, t, env->prog, &info)) {
+		/* A non zero info.ctx_field_size indicates that this field is a
+		 * candidate for later verifier transformation to load the whole
+		 * field and then apply a mask when accessed with a narrower
+		 * access than actual ctx access size. A zero info.ctx_field_size
+		 * will only allow for whole field access and rejects any other
+		 * type of narrower access.
+		 */
+		*reg_type = info.reg_type;
+
+		if (base_type(*reg_type) == PTR_TO_BTF_ID) {
+			*btf = info.btf;
+			*btf_id = info.btf_id;
+		} else {
+			env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size;
+		}
+		/* remember the offset of last byte accessed in ctx */
+		if (env->prog->aux->max_ctx_offset < off + size)
+			env->prog->aux->max_ctx_offset = off + size;
+		return 0;
+	}
+
+	verbose(env, "invalid bpf_context access off=%d size=%d\n", off, size);
+	return -EACCES;
+}
+
+static int check_flow_keys_access(struct bpf_verifier_env *env, int off,
+				  int size)
+{
+	if (size < 0 || off < 0 ||
+	    (u64)off + size > sizeof(struct bpf_flow_keys)) {
+		verbose(env, "invalid access to flow keys off=%d size=%d\n",
+			off, size);
+		return -EACCES;
+	}
+	return 0;
+}
+
+static int check_sock_access(struct bpf_verifier_env *env, int insn_idx,
+			     u32 regno, int off, int size,
+			     enum bpf_access_type t)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *reg = &regs[regno];
+	struct bpf_insn_access_aux info = {};
+	bool valid;
+
+	if (reg->smin_value < 0) {
+		verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
+			regno);
+		return -EACCES;
+	}
+
+	switch (reg->type) {
+	case PTR_TO_SOCK_COMMON:
+		valid = bpf_sock_common_is_valid_access(off, size, t, &info);
+		break;
+	case PTR_TO_SOCKET:
+		valid = bpf_sock_is_valid_access(off, size, t, &info);
+		break;
+	case PTR_TO_TCP_SOCK:
+		valid = bpf_tcp_sock_is_valid_access(off, size, t, &info);
+		break;
+	case PTR_TO_XDP_SOCK:
+		valid = bpf_xdp_sock_is_valid_access(off, size, t, &info);
+		break;
+	default:
+		valid = false;
+	}
+
+
+	if (valid) {
+		env->insn_aux_data[insn_idx].ctx_field_size =
+			info.ctx_field_size;
+		return 0;
+	}
+
+	verbose(env, "R%d invalid %s access off=%d size=%d\n",
+		regno, reg_type_str(env, reg->type), off, size);
+
+	return -EACCES;
+}
+
+static bool is_pointer_value(struct bpf_verifier_env *env, int regno)
+{
+	return __is_pointer_value(env->allow_ptr_leaks, reg_state(env, regno));
+}
+
+static bool is_ctx_reg(struct bpf_verifier_env *env, int regno)
+{
+	const struct bpf_reg_state *reg = reg_state(env, regno);
+
+	return reg->type == PTR_TO_CTX;
+}
+
+static bool is_sk_reg(struct bpf_verifier_env *env, int regno)
+{
+	const struct bpf_reg_state *reg = reg_state(env, regno);
+
+	return type_is_sk_pointer(reg->type);
+}
+
+static bool is_pkt_reg(struct bpf_verifier_env *env, int regno)
+{
+	const struct bpf_reg_state *reg = reg_state(env, regno);
+
+	return type_is_pkt_pointer(reg->type);
+}
+
+static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno)
+{
+	const struct bpf_reg_state *reg = reg_state(env, regno);
+
+	/* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */
+	return reg->type == PTR_TO_FLOW_KEYS;
+}
+
+static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
+				   const struct bpf_reg_state *reg,
+				   int off, int size, bool strict)
+{
+	struct tnum reg_off;
+	int ip_align;
+
+	/* Byte size accesses are always allowed. */
+	if (!strict || size == 1)
+		return 0;
+
+	/* For platforms that do not have a Kconfig enabling
+	 * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of
+	 * NET_IP_ALIGN is universally set to '2'.  And on platforms
+	 * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get
+	 * to this code only in strict mode where we want to emulate
+	 * the NET_IP_ALIGN==2 checking.  Therefore use an
+	 * unconditional IP align value of '2'.
+	 */
+	ip_align = 2;
+
+	reg_off = tnum_add(reg->var_off, tnum_const(ip_align + reg->off + off));
+	if (!tnum_is_aligned(reg_off, size)) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env,
+			"misaligned packet access off %d+%s+%d+%d size %d\n",
+			ip_align, tn_buf, reg->off, off, size);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+static int check_generic_ptr_alignment(struct bpf_verifier_env *env,
+				       const struct bpf_reg_state *reg,
+				       const char *pointer_desc,
+				       int off, int size, bool strict)
+{
+	struct tnum reg_off;
+
+	/* Byte size accesses are always allowed. */
+	if (!strict || size == 1)
+		return 0;
+
+	reg_off = tnum_add(reg->var_off, tnum_const(reg->off + off));
+	if (!tnum_is_aligned(reg_off, size)) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env, "misaligned %saccess off %s+%d+%d size %d\n",
+			pointer_desc, tn_buf, reg->off, off, size);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+static int check_ptr_alignment(struct bpf_verifier_env *env,
+			       const struct bpf_reg_state *reg, int off,
+			       int size, bool strict_alignment_once)
+{
+	bool strict = env->strict_alignment || strict_alignment_once;
+	const char *pointer_desc = "";
+
+	switch (reg->type) {
+	case PTR_TO_PACKET:
+	case PTR_TO_PACKET_META:
+		/* Special case, because of NET_IP_ALIGN. Given metadata sits
+		 * right in front, treat it the very same way.
+		 */
+		return check_pkt_ptr_alignment(env, reg, off, size, strict);
+	case PTR_TO_FLOW_KEYS:
+		pointer_desc = "flow keys ";
+		break;
+	case PTR_TO_MAP_KEY:
+		pointer_desc = "key ";
+		break;
+	case PTR_TO_MAP_VALUE:
+		pointer_desc = "value ";
+		break;
+	case PTR_TO_CTX:
+		pointer_desc = "context ";
+		break;
+	case PTR_TO_STACK:
+		pointer_desc = "stack ";
+		/* The stack spill tracking logic in check_stack_write_fixed_off()
+		 * and check_stack_read_fixed_off() relies on stack accesses being
+		 * aligned.
+		 */
+		strict = true;
+		break;
+	case PTR_TO_SOCKET:
+		pointer_desc = "sock ";
+		break;
+	case PTR_TO_SOCK_COMMON:
+		pointer_desc = "sock_common ";
+		break;
+	case PTR_TO_TCP_SOCK:
+		pointer_desc = "tcp_sock ";
+		break;
+	case PTR_TO_XDP_SOCK:
+		pointer_desc = "xdp_sock ";
+		break;
+	default:
+		break;
+	}
+	return check_generic_ptr_alignment(env, reg, pointer_desc, off, size,
+					   strict);
+}
+
+static int update_stack_depth(struct bpf_verifier_env *env,
+			      const struct bpf_func_state *func,
+			      int off)
+{
+	u16 stack = env->subprog_info[func->subprogno].stack_depth;
+
+	if (stack >= -off)
+		return 0;
+
+	/* update known max for given subprogram */
+	env->subprog_info[func->subprogno].stack_depth = -off;
+	return 0;
+}
+
+/* starting from main bpf function walk all instructions of the function
+ * and recursively walk all callees that given function can call.
+ * Ignore jump and exit insns.
+ * Since recursion is prevented by check_cfg() this algorithm
+ * only needs a local stack of MAX_CALL_FRAMES to remember callsites
+ */
+static int check_max_stack_depth_subprog(struct bpf_verifier_env *env, int idx)
+{
+	struct bpf_subprog_info *subprog = env->subprog_info;
+	struct bpf_insn *insn = env->prog->insnsi;
+	int depth = 0, frame = 0, i, subprog_end;
+	bool tail_call_reachable = false;
+	int ret_insn[MAX_CALL_FRAMES];
+	int ret_prog[MAX_CALL_FRAMES];
+	int j;
+
+	i = subprog[idx].start;
+process_func:
+	/* protect against potential stack overflow that might happen when
+	 * bpf2bpf calls get combined with tailcalls. Limit the caller's stack
+	 * depth for such case down to 256 so that the worst case scenario
+	 * would result in 8k stack size (32 which is tailcall limit * 256 =
+	 * 8k).
+	 *
+	 * To get the idea what might happen, see an example:
+	 * func1 -> sub rsp, 128
+	 *  subfunc1 -> sub rsp, 256
+	 *  tailcall1 -> add rsp, 256
+	 *   func2 -> sub rsp, 192 (total stack size = 128 + 192 = 320)
+	 *   subfunc2 -> sub rsp, 64
+	 *   subfunc22 -> sub rsp, 128
+	 *   tailcall2 -> add rsp, 128
+	 *    func3 -> sub rsp, 32 (total stack size 128 + 192 + 64 + 32 = 416)
+	 *
+	 * tailcall will unwind the current stack frame but it will not get rid
+	 * of caller's stack as shown on the example above.
+	 */
+	if (idx && subprog[idx].has_tail_call && depth >= 256) {
+		verbose(env,
+			"tail_calls are not allowed when call stack of previous frames is %d bytes. Too large\n",
+			depth);
+		return -EACCES;
+	}
+	/* round up to 32-bytes, since this is granularity
+	 * of interpreter stack size
+	 */
+	depth += round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
+	if (depth > MAX_BPF_STACK) {
+		verbose(env, "combined stack size of %d calls is %d. Too large\n",
+			frame + 1, depth);
+		return -EACCES;
+	}
+continue_func:
+	subprog_end = subprog[idx + 1].start;
+	for (; i < subprog_end; i++) {
+		int next_insn, sidx;
+
+		if (!bpf_pseudo_call(insn + i) && !bpf_pseudo_func(insn + i))
+			continue;
+		/* remember insn and function to return to */
+		ret_insn[frame] = i + 1;
+		ret_prog[frame] = idx;
+
+		/* find the callee */
+		next_insn = i + insn[i].imm + 1;
+		sidx = find_subprog(env, next_insn);
+		if (sidx < 0) {
+			WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
+				  next_insn);
+			return -EFAULT;
+		}
+		if (subprog[sidx].is_async_cb) {
+			if (subprog[sidx].has_tail_call) {
+				verbose(env, "verifier bug. subprog has tail_call and async cb\n");
+				return -EFAULT;
+			}
+			/* async callbacks don't increase bpf prog stack size unless called directly */
+			if (!bpf_pseudo_call(insn + i))
+				continue;
+		}
+		i = next_insn;
+		idx = sidx;
+
+		if (subprog[idx].has_tail_call)
+			tail_call_reachable = true;
+
+		frame++;
+		if (frame >= MAX_CALL_FRAMES) {
+			verbose(env, "the call stack of %d frames is too deep !\n",
+				frame);
+			return -E2BIG;
+		}
+		goto process_func;
+	}
+	/* if tail call got detected across bpf2bpf calls then mark each of the
+	 * currently present subprog frames as tail call reachable subprogs;
+	 * this info will be utilized by JIT so that we will be preserving the
+	 * tail call counter throughout bpf2bpf calls combined with tailcalls
+	 */
+	if (tail_call_reachable)
+		for (j = 0; j < frame; j++)
+			subprog[ret_prog[j]].tail_call_reachable = true;
+	if (subprog[0].tail_call_reachable)
+		env->prog->aux->tail_call_reachable = true;
+
+	/* end of for() loop means the last insn of the 'subprog'
+	 * was reached. Doesn't matter whether it was JA or EXIT
+	 */
+	if (frame == 0)
+		return 0;
+	depth -= round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
+	frame--;
+	i = ret_insn[frame];
+	idx = ret_prog[frame];
+	goto continue_func;
+}
+
+static int check_max_stack_depth(struct bpf_verifier_env *env)
+{
+	struct bpf_subprog_info *si = env->subprog_info;
+	int ret;
+
+	for (int i = 0; i < env->subprog_cnt; i++) {
+		if (!i || si[i].is_async_cb) {
+			ret = check_max_stack_depth_subprog(env, i);
+			if (ret < 0)
+				return ret;
+		}
+		continue;
+	}
+	return 0;
+}
+
+#ifndef CONFIG_BPF_JIT_ALWAYS_ON
+static int get_callee_stack_depth(struct bpf_verifier_env *env,
+				  const struct bpf_insn *insn, int idx)
+{
+	int start = idx + insn->imm + 1, subprog;
+
+	subprog = find_subprog(env, start);
+	if (subprog < 0) {
+		WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
+			  start);
+		return -EFAULT;
+	}
+	return env->subprog_info[subprog].stack_depth;
+}
+#endif
+
+static int __check_buffer_access(struct bpf_verifier_env *env,
+				 const char *buf_info,
+				 const struct bpf_reg_state *reg,
+				 int regno, int off, int size)
+{
+	if (off < 0) {
+		verbose(env,
+			"R%d invalid %s buffer access: off=%d, size=%d\n",
+			regno, buf_info, off, size);
+		return -EACCES;
+	}
+	if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env,
+			"R%d invalid variable buffer offset: off=%d, var_off=%s\n",
+			regno, off, tn_buf);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+static int check_tp_buffer_access(struct bpf_verifier_env *env,
+				  const struct bpf_reg_state *reg,
+				  int regno, int off, int size)
+{
+	int err;
+
+	err = __check_buffer_access(env, "tracepoint", reg, regno, off, size);
+	if (err)
+		return err;
+
+	if (off + size > env->prog->aux->max_tp_access)
+		env->prog->aux->max_tp_access = off + size;
+
+	return 0;
+}
+
+static int check_buffer_access(struct bpf_verifier_env *env,
+			       const struct bpf_reg_state *reg,
+			       int regno, int off, int size,
+			       bool zero_size_allowed,
+			       u32 *max_access)
+{
+	const char *buf_info = type_is_rdonly_mem(reg->type) ? "rdonly" : "rdwr";
+	int err;
+
+	err = __check_buffer_access(env, buf_info, reg, regno, off, size);
+	if (err)
+		return err;
+
+	if (off + size > *max_access)
+		*max_access = off + size;
+
+	return 0;
+}
+
+/* BPF architecture zero extends alu32 ops into 64-bit registesr */
+static void zext_32_to_64(struct bpf_reg_state *reg)
+{
+	reg->var_off = tnum_subreg(reg->var_off);
+	__reg_assign_32_into_64(reg);
+}
+
+/* truncate register to smaller size (in bytes)
+ * must be called with size < BPF_REG_SIZE
+ */
+static void coerce_reg_to_size(struct bpf_reg_state *reg, int size)
+{
+	u64 mask;
+
+	/* clear high bits in bit representation */
+	reg->var_off = tnum_cast(reg->var_off, size);
+
+	/* fix arithmetic bounds */
+	mask = ((u64)1 << (size * 8)) - 1;
+	if ((reg->umin_value & ~mask) == (reg->umax_value & ~mask)) {
+		reg->umin_value &= mask;
+		reg->umax_value &= mask;
+	} else {
+		reg->umin_value = 0;
+		reg->umax_value = mask;
+	}
+	reg->smin_value = reg->umin_value;
+	reg->smax_value = reg->umax_value;
+
+	/* If size is smaller than 32bit register the 32bit register
+	 * values are also truncated so we push 64-bit bounds into
+	 * 32-bit bounds. Above were truncated < 32-bits already.
+	 */
+	if (size >= 4)
+		return;
+	__reg_combine_64_into_32(reg);
+}
+
+static bool bpf_map_is_rdonly(const struct bpf_map *map)
+{
+	/* A map is considered read-only if the following condition are true:
+	 *
+	 * 1) BPF program side cannot change any of the map content. The
+	 *    BPF_F_RDONLY_PROG flag is throughout the lifetime of a map
+	 *    and was set at map creation time.
+	 * 2) The map value(s) have been initialized from user space by a
+	 *    loader and then "frozen", such that no new map update/delete
+	 *    operations from syscall side are possible for the rest of
+	 *    the map's lifetime from that point onwards.
+	 * 3) Any parallel/pending map update/delete operations from syscall
+	 *    side have been completed. Only after that point, it's safe to
+	 *    assume that map value(s) are immutable.
+	 */
+	return (map->map_flags & BPF_F_RDONLY_PROG) &&
+	       READ_ONCE(map->frozen) &&
+	       !bpf_map_write_active(map);
+}
+
+static int bpf_map_direct_read(struct bpf_map *map, int off, int size, u64 *val)
+{
+	void *ptr;
+	u64 addr;
+	int err;
+
+	err = map->ops->map_direct_value_addr(map, &addr, off);
+	if (err)
+		return err;
+	ptr = (void *)(long)addr + off;
+
+	switch (size) {
+	case sizeof(u8):
+		*val = (u64)*(u8 *)ptr;
+		break;
+	case sizeof(u16):
+		*val = (u64)*(u16 *)ptr;
+		break;
+	case sizeof(u32):
+		*val = (u64)*(u32 *)ptr;
+		break;
+	case sizeof(u64):
+		*val = *(u64 *)ptr;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *regs,
+				   int regno, int off, int size,
+				   enum bpf_access_type atype,
+				   int value_regno)
+{
+	struct bpf_reg_state *reg = regs + regno;
+	const struct btf_type *t = btf_type_by_id(reg->btf, reg->btf_id);
+	const char *tname = btf_name_by_offset(reg->btf, t->name_off);
+	enum bpf_type_flag flag = 0;
+	u32 btf_id;
+	int ret;
+
+	if (off < 0) {
+		verbose(env,
+			"R%d is ptr_%s invalid negative access: off=%d\n",
+			regno, tname, off);
+		return -EACCES;
+	}
+	if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env,
+			"R%d is ptr_%s invalid variable offset: off=%d, var_off=%s\n",
+			regno, tname, off, tn_buf);
+		return -EACCES;
+	}
+
+	if (reg->type & MEM_USER) {
+		verbose(env,
+			"R%d is ptr_%s access user memory: off=%d\n",
+			regno, tname, off);
+		return -EACCES;
+	}
+
+	if (reg->type & MEM_PERCPU) {
+		verbose(env,
+			"R%d is ptr_%s access percpu memory: off=%d\n",
+			regno, tname, off);
+		return -EACCES;
+	}
+
+	if (env->ops->btf_struct_access) {
+		ret = env->ops->btf_struct_access(&env->log, reg->btf, t,
+						  off, size, atype, &btf_id, &flag);
+	} else {
+		if (atype != BPF_READ) {
+			verbose(env, "only read is supported\n");
+			return -EACCES;
+		}
+
+		ret = btf_struct_access(&env->log, reg->btf, t, off, size,
+					atype, &btf_id, &flag);
+	}
+
+	if (ret < 0)
+		return ret;
+
+	/* If this is an untrusted pointer, all pointers formed by walking it
+	 * also inherit the untrusted flag.
+	 */
+	if (type_flag(reg->type) & PTR_UNTRUSTED)
+		flag |= PTR_UNTRUSTED;
+
+	if (atype == BPF_READ && value_regno >= 0)
+		mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id, flag);
+
+	return 0;
+}
+
+static int check_ptr_to_map_access(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *regs,
+				   int regno, int off, int size,
+				   enum bpf_access_type atype,
+				   int value_regno)
+{
+	struct bpf_reg_state *reg = regs + regno;
+	struct bpf_map *map = reg->map_ptr;
+	enum bpf_type_flag flag = 0;
+	const struct btf_type *t;
+	const char *tname;
+	u32 btf_id;
+	int ret;
+
+	if (!btf_vmlinux) {
+		verbose(env, "map_ptr access not supported without CONFIG_DEBUG_INFO_BTF\n");
+		return -ENOTSUPP;
+	}
+
+	if (!map->ops->map_btf_id || !*map->ops->map_btf_id) {
+		verbose(env, "map_ptr access not supported for map type %d\n",
+			map->map_type);
+		return -ENOTSUPP;
+	}
+
+	t = btf_type_by_id(btf_vmlinux, *map->ops->map_btf_id);
+	tname = btf_name_by_offset(btf_vmlinux, t->name_off);
+
+	if (!env->allow_ptr_to_map_access) {
+		verbose(env,
+			"%s access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN\n",
+			tname);
+		return -EPERM;
+	}
+
+	if (off < 0) {
+		verbose(env, "R%d is %s invalid negative access: off=%d\n",
+			regno, tname, off);
+		return -EACCES;
+	}
+
+	if (atype != BPF_READ) {
+		verbose(env, "only read from %s is supported\n", tname);
+		return -EACCES;
+	}
+
+	ret = btf_struct_access(&env->log, btf_vmlinux, t, off, size, atype, &btf_id, &flag);
+	if (ret < 0)
+		return ret;
+
+	if (value_regno >= 0)
+		mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id, flag);
+
+	return 0;
+}
+
+/* Check that the stack access at the given offset is within bounds. The
+ * maximum valid offset is -1.
+ *
+ * The minimum valid offset is -MAX_BPF_STACK for writes, and
+ * -state->allocated_stack for reads.
+ */
+static int check_stack_slot_within_bounds(int off,
+					  struct bpf_func_state *state,
+					  enum bpf_access_type t)
+{
+	int min_valid_off;
+
+	if (t == BPF_WRITE)
+		min_valid_off = -MAX_BPF_STACK;
+	else
+		min_valid_off = -state->allocated_stack;
+
+	if (off < min_valid_off || off > -1)
+		return -EACCES;
+	return 0;
+}
+
+/* Check that the stack access at 'regno + off' falls within the maximum stack
+ * bounds.
+ *
+ * 'off' includes `regno->offset`, but not its dynamic part (if any).
+ */
+static int check_stack_access_within_bounds(
+		struct bpf_verifier_env *env,
+		int regno, int off, int access_size,
+		enum bpf_access_src src, enum bpf_access_type type)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *reg = regs + regno;
+	struct bpf_func_state *state = func(env, reg);
+	int min_off, max_off;
+	int err;
+	char *err_extra;
+
+	if (src == ACCESS_HELPER)
+		/* We don't know if helpers are reading or writing (or both). */
+		err_extra = " indirect access to";
+	else if (type == BPF_READ)
+		err_extra = " read from";
+	else
+		err_extra = " write to";
+
+	if (tnum_is_const(reg->var_off)) {
+		min_off = reg->var_off.value + off;
+		max_off = min_off + access_size;
+	} else {
+		if (reg->smax_value >= BPF_MAX_VAR_OFF ||
+		    reg->smin_value <= -BPF_MAX_VAR_OFF) {
+			verbose(env, "invalid unbounded variable-offset%s stack R%d\n",
+				err_extra, regno);
+			return -EACCES;
+		}
+		min_off = reg->smin_value + off;
+		max_off = reg->smax_value + off + access_size;
+	}
+
+	err = check_stack_slot_within_bounds(min_off, state, type);
+	if (!err && max_off > 0)
+		err = -EINVAL; /* out of stack access into non-negative offsets */
+
+	if (err) {
+		if (tnum_is_const(reg->var_off)) {
+			verbose(env, "invalid%s stack R%d off=%d size=%d\n",
+				err_extra, regno, off, access_size);
+		} else {
+			char tn_buf[48];
+
+			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+			verbose(env, "invalid variable-offset%s stack R%d var_off=%s size=%d\n",
+				err_extra, regno, tn_buf, access_size);
+		}
+	}
+	return err;
+}
+
+/* check whether memory at (regno + off) is accessible for t = (read | write)
+ * if t==write, value_regno is a register which value is stored into memory
+ * if t==read, value_regno is a register which will receive the value from memory
+ * if t==write && value_regno==-1, some unknown value is stored into memory
+ * if t==read && value_regno==-1, don't care what we read from memory
+ */
+static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno,
+			    int off, int bpf_size, enum bpf_access_type t,
+			    int value_regno, bool strict_alignment_once)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *reg = regs + regno;
+	struct bpf_func_state *state;
+	int size, err = 0;
+
+	size = bpf_size_to_bytes(bpf_size);
+	if (size < 0)
+		return size;
+
+	/* alignment checks will add in reg->off themselves */
+	err = check_ptr_alignment(env, reg, off, size, strict_alignment_once);
+	if (err)
+		return err;
+
+	/* for access checks, reg->off is just part of off */
+	off += reg->off;
+
+	if (reg->type == PTR_TO_MAP_KEY) {
+		if (t == BPF_WRITE) {
+			verbose(env, "write to change key R%d not allowed\n", regno);
+			return -EACCES;
+		}
+
+		err = check_mem_region_access(env, regno, off, size,
+					      reg->map_ptr->key_size, false);
+		if (err)
+			return err;
+		if (value_regno >= 0)
+			mark_reg_unknown(env, regs, value_regno);
+	} else if (reg->type == PTR_TO_MAP_VALUE) {
+		struct bpf_map_value_off_desc *kptr_off_desc = NULL;
+
+		if (t == BPF_WRITE && value_regno >= 0 &&
+		    is_pointer_value(env, value_regno)) {
+			verbose(env, "R%d leaks addr into map\n", value_regno);
+			return -EACCES;
+		}
+		err = check_map_access_type(env, regno, off, size, t);
+		if (err)
+			return err;
+		err = check_map_access(env, regno, off, size, false, ACCESS_DIRECT);
+		if (err)
+			return err;
+		if (tnum_is_const(reg->var_off))
+			kptr_off_desc = bpf_map_kptr_off_contains(reg->map_ptr,
+								  off + reg->var_off.value);
+		if (kptr_off_desc) {
+			err = check_map_kptr_access(env, regno, value_regno, insn_idx,
+						    kptr_off_desc);
+		} else if (t == BPF_READ && value_regno >= 0) {
+			struct bpf_map *map = reg->map_ptr;
+
+			/* if map is read-only, track its contents as scalars */
+			if (tnum_is_const(reg->var_off) &&
+			    bpf_map_is_rdonly(map) &&
+			    map->ops->map_direct_value_addr) {
+				int map_off = off + reg->var_off.value;
+				u64 val = 0;
+
+				err = bpf_map_direct_read(map, map_off, size,
+							  &val);
+				if (err)
+					return err;
+
+				regs[value_regno].type = SCALAR_VALUE;
+				__mark_reg_known(&regs[value_regno], val);
+			} else {
+				mark_reg_unknown(env, regs, value_regno);
+			}
+		}
+	} else if (base_type(reg->type) == PTR_TO_MEM) {
+		bool rdonly_mem = type_is_rdonly_mem(reg->type);
+
+		if (type_may_be_null(reg->type)) {
+			verbose(env, "R%d invalid mem access '%s'\n", regno,
+				reg_type_str(env, reg->type));
+			return -EACCES;
+		}
+
+		if (t == BPF_WRITE && rdonly_mem) {
+			verbose(env, "R%d cannot write into %s\n",
+				regno, reg_type_str(env, reg->type));
+			return -EACCES;
+		}
+
+		if (t == BPF_WRITE && value_regno >= 0 &&
+		    is_pointer_value(env, value_regno)) {
+			verbose(env, "R%d leaks addr into mem\n", value_regno);
+			return -EACCES;
+		}
+
+		err = check_mem_region_access(env, regno, off, size,
+					      reg->mem_size, false);
+		if (!err && value_regno >= 0 && (t == BPF_READ || rdonly_mem))
+			mark_reg_unknown(env, regs, value_regno);
+	} else if (reg->type == PTR_TO_CTX) {
+		enum bpf_reg_type reg_type = SCALAR_VALUE;
+		struct btf *btf = NULL;
+		u32 btf_id = 0;
+
+		if (t == BPF_WRITE && value_regno >= 0 &&
+		    is_pointer_value(env, value_regno)) {
+			verbose(env, "R%d leaks addr into ctx\n", value_regno);
+			return -EACCES;
+		}
+
+		err = check_ptr_off_reg(env, reg, regno);
+		if (err < 0)
+			return err;
+
+		err = check_ctx_access(env, insn_idx, off, size, t, &reg_type, &btf,
+				       &btf_id);
+		if (err)
+			verbose_linfo(env, insn_idx, "; ");
+		if (!err && t == BPF_READ && value_regno >= 0) {
+			/* ctx access returns either a scalar, or a
+			 * PTR_TO_PACKET[_META,_END]. In the latter
+			 * case, we know the offset is zero.
+			 */
+			if (reg_type == SCALAR_VALUE) {
+				mark_reg_unknown(env, regs, value_regno);
+			} else {
+				mark_reg_known_zero(env, regs,
+						    value_regno);
+				if (type_may_be_null(reg_type))
+					regs[value_regno].id = ++env->id_gen;
+				/* A load of ctx field could have different
+				 * actual load size with the one encoded in the
+				 * insn. When the dst is PTR, it is for sure not
+				 * a sub-register.
+				 */
+				regs[value_regno].subreg_def = DEF_NOT_SUBREG;
+				if (base_type(reg_type) == PTR_TO_BTF_ID) {
+					regs[value_regno].btf = btf;
+					regs[value_regno].btf_id = btf_id;
+				}
+			}
+			regs[value_regno].type = reg_type;
+		}
+
+	} else if (reg->type == PTR_TO_STACK) {
+		/* Basic bounds checks. */
+		err = check_stack_access_within_bounds(env, regno, off, size, ACCESS_DIRECT, t);
+		if (err)
+			return err;
+
+		state = func(env, reg);
+		err = update_stack_depth(env, state, off);
+		if (err)
+			return err;
+
+		if (t == BPF_READ)
+			err = check_stack_read(env, regno, off, size,
+					       value_regno);
+		else
+			err = check_stack_write(env, regno, off, size,
+						value_regno, insn_idx);
+	} else if (reg_is_pkt_pointer(reg)) {
+		if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) {
+			verbose(env, "cannot write into packet\n");
+			return -EACCES;
+		}
+		if (t == BPF_WRITE && value_regno >= 0 &&
+		    is_pointer_value(env, value_regno)) {
+			verbose(env, "R%d leaks addr into packet\n",
+				value_regno);
+			return -EACCES;
+		}
+		err = check_packet_access(env, regno, off, size, false);
+		if (!err && t == BPF_READ && value_regno >= 0)
+			mark_reg_unknown(env, regs, value_regno);
+	} else if (reg->type == PTR_TO_FLOW_KEYS) {
+		if (t == BPF_WRITE && value_regno >= 0 &&
+		    is_pointer_value(env, value_regno)) {
+			verbose(env, "R%d leaks addr into flow keys\n",
+				value_regno);
+			return -EACCES;
+		}
+
+		err = check_flow_keys_access(env, off, size);
+		if (!err && t == BPF_READ && value_regno >= 0)
+			mark_reg_unknown(env, regs, value_regno);
+	} else if (type_is_sk_pointer(reg->type)) {
+		if (t == BPF_WRITE) {
+			verbose(env, "R%d cannot write into %s\n",
+				regno, reg_type_str(env, reg->type));
+			return -EACCES;
+		}
+		err = check_sock_access(env, insn_idx, regno, off, size, t);
+		if (!err && value_regno >= 0)
+			mark_reg_unknown(env, regs, value_regno);
+	} else if (reg->type == PTR_TO_TP_BUFFER) {
+		err = check_tp_buffer_access(env, reg, regno, off, size);
+		if (!err && t == BPF_READ && value_regno >= 0)
+			mark_reg_unknown(env, regs, value_regno);
+	} else if (base_type(reg->type) == PTR_TO_BTF_ID &&
+		   !type_may_be_null(reg->type)) {
+		err = check_ptr_to_btf_access(env, regs, regno, off, size, t,
+					      value_regno);
+	} else if (reg->type == CONST_PTR_TO_MAP) {
+		err = check_ptr_to_map_access(env, regs, regno, off, size, t,
+					      value_regno);
+	} else if (base_type(reg->type) == PTR_TO_BUF) {
+		bool rdonly_mem = type_is_rdonly_mem(reg->type);
+		u32 *max_access;
+
+		if (rdonly_mem) {
+			if (t == BPF_WRITE) {
+				verbose(env, "R%d cannot write into %s\n",
+					regno, reg_type_str(env, reg->type));
+				return -EACCES;
+			}
+			max_access = &env->prog->aux->max_rdonly_access;
+		} else {
+			max_access = &env->prog->aux->max_rdwr_access;
+		}
+
+		err = check_buffer_access(env, reg, regno, off, size, false,
+					  max_access);
+
+		if (!err && value_regno >= 0 && (rdonly_mem || t == BPF_READ))
+			mark_reg_unknown(env, regs, value_regno);
+	} else {
+		verbose(env, "R%d invalid mem access '%s'\n", regno,
+			reg_type_str(env, reg->type));
+		return -EACCES;
+	}
+
+	if (!err && size < BPF_REG_SIZE && value_regno >= 0 && t == BPF_READ &&
+	    regs[value_regno].type == SCALAR_VALUE) {
+		/* b/h/w load zero-extends, mark upper bits as known 0 */
+		coerce_reg_to_size(&regs[value_regno], size);
+	}
+	return err;
+}
+
+static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_insn *insn)
+{
+	int load_reg;
+	int err;
+
+	switch (insn->imm) {
+	case BPF_ADD:
+	case BPF_ADD | BPF_FETCH:
+	case BPF_AND:
+	case BPF_AND | BPF_FETCH:
+	case BPF_OR:
+	case BPF_OR | BPF_FETCH:
+	case BPF_XOR:
+	case BPF_XOR | BPF_FETCH:
+	case BPF_XCHG:
+	case BPF_CMPXCHG:
+		break;
+	default:
+		verbose(env, "BPF_ATOMIC uses invalid atomic opcode %02x\n", insn->imm);
+		return -EINVAL;
+	}
+
+	if (BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) {
+		verbose(env, "invalid atomic operand size\n");
+		return -EINVAL;
+	}
+
+	/* check src1 operand */
+	err = check_reg_arg(env, insn->src_reg, SRC_OP);
+	if (err)
+		return err;
+
+	/* check src2 operand */
+	err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+	if (err)
+		return err;
+
+	if (insn->imm == BPF_CMPXCHG) {
+		/* Check comparison of R0 with memory location */
+		const u32 aux_reg = BPF_REG_0;
+
+		err = check_reg_arg(env, aux_reg, SRC_OP);
+		if (err)
+			return err;
+
+		if (is_pointer_value(env, aux_reg)) {
+			verbose(env, "R%d leaks addr into mem\n", aux_reg);
+			return -EACCES;
+		}
+	}
+
+	if (is_pointer_value(env, insn->src_reg)) {
+		verbose(env, "R%d leaks addr into mem\n", insn->src_reg);
+		return -EACCES;
+	}
+
+	if (is_ctx_reg(env, insn->dst_reg) ||
+	    is_pkt_reg(env, insn->dst_reg) ||
+	    is_flow_key_reg(env, insn->dst_reg) ||
+	    is_sk_reg(env, insn->dst_reg)) {
+		verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n",
+			insn->dst_reg,
+			reg_type_str(env, reg_state(env, insn->dst_reg)->type));
+		return -EACCES;
+	}
+
+	if (insn->imm & BPF_FETCH) {
+		if (insn->imm == BPF_CMPXCHG)
+			load_reg = BPF_REG_0;
+		else
+			load_reg = insn->src_reg;
+
+		/* check and record load of old value */
+		err = check_reg_arg(env, load_reg, DST_OP);
+		if (err)
+			return err;
+	} else {
+		/* This instruction accesses a memory location but doesn't
+		 * actually load it into a register.
+		 */
+		load_reg = -1;
+	}
+
+	/* Check whether we can read the memory, with second call for fetch
+	 * case to simulate the register fill.
+	 */
+	err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
+			       BPF_SIZE(insn->code), BPF_READ, -1, true);
+	if (!err && load_reg >= 0)
+		err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
+				       BPF_SIZE(insn->code), BPF_READ, load_reg,
+				       true);
+	if (err)
+		return err;
+
+	/* Check whether we can write into the same memory. */
+	err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
+			       BPF_SIZE(insn->code), BPF_WRITE, -1, true);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+/* When register 'regno' is used to read the stack (either directly or through
+ * a helper function) make sure that it's within stack boundary and, depending
+ * on the access type, that all elements of the stack are initialized.
+ *
+ * 'off' includes 'regno->off', but not its dynamic part (if any).
+ *
+ * All registers that have been spilled on the stack in the slots within the
+ * read offsets are marked as read.
+ */
+static int check_stack_range_initialized(
+		struct bpf_verifier_env *env, int regno, int off,
+		int access_size, bool zero_size_allowed,
+		enum bpf_access_src type, struct bpf_call_arg_meta *meta)
+{
+	struct bpf_reg_state *reg = reg_state(env, regno);
+	struct bpf_func_state *state = func(env, reg);
+	int err, min_off, max_off, i, j, slot, spi;
+	char *err_extra = type == ACCESS_HELPER ? " indirect" : "";
+	enum bpf_access_type bounds_check_type;
+	/* Some accesses can write anything into the stack, others are
+	 * read-only.
+	 */
+	bool clobber = false;
+
+	if (access_size == 0 && !zero_size_allowed) {
+		verbose(env, "invalid zero-sized read\n");
+		return -EACCES;
+	}
+
+	if (type == ACCESS_HELPER) {
+		/* The bounds checks for writes are more permissive than for
+		 * reads. However, if raw_mode is not set, we'll do extra
+		 * checks below.
+		 */
+		bounds_check_type = BPF_WRITE;
+		clobber = true;
+	} else {
+		bounds_check_type = BPF_READ;
+	}
+	err = check_stack_access_within_bounds(env, regno, off, access_size,
+					       type, bounds_check_type);
+	if (err)
+		return err;
+
+
+	if (tnum_is_const(reg->var_off)) {
+		min_off = max_off = reg->var_off.value + off;
+	} else {
+		/* Variable offset is prohibited for unprivileged mode for
+		 * simplicity since it requires corresponding support in
+		 * Spectre masking for stack ALU.
+		 * See also retrieve_ptr_limit().
+		 */
+		if (!env->bypass_spec_v1) {
+			char tn_buf[48];
+
+			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+			verbose(env, "R%d%s variable offset stack access prohibited for !root, var_off=%s\n",
+				regno, err_extra, tn_buf);
+			return -EACCES;
+		}
+		/* Only initialized buffer on stack is allowed to be accessed
+		 * with variable offset. With uninitialized buffer it's hard to
+		 * guarantee that whole memory is marked as initialized on
+		 * helper return since specific bounds are unknown what may
+		 * cause uninitialized stack leaking.
+		 */
+		if (meta && meta->raw_mode)
+			meta = NULL;
+
+		min_off = reg->smin_value + off;
+		max_off = reg->smax_value + off;
+	}
+
+	if (meta && meta->raw_mode) {
+		meta->access_size = access_size;
+		meta->regno = regno;
+		return 0;
+	}
+
+	for (i = min_off; i < max_off + access_size; i++) {
+		u8 *stype;
+
+		slot = -i - 1;
+		spi = slot / BPF_REG_SIZE;
+		if (state->allocated_stack <= slot)
+			goto err;
+		stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
+		if (*stype == STACK_MISC)
+			goto mark;
+		if (*stype == STACK_ZERO) {
+			if (clobber) {
+				/* helper can write anything into the stack */
+				*stype = STACK_MISC;
+			}
+			goto mark;
+		}
+
+		if (is_spilled_reg(&state->stack[spi]) &&
+		    (state->stack[spi].spilled_ptr.type == SCALAR_VALUE ||
+		     env->allow_ptr_leaks)) {
+			if (clobber) {
+				__mark_reg_unknown(env, &state->stack[spi].spilled_ptr);
+				for (j = 0; j < BPF_REG_SIZE; j++)
+					scrub_spilled_slot(&state->stack[spi].slot_type[j]);
+			}
+			goto mark;
+		}
+
+err:
+		if (tnum_is_const(reg->var_off)) {
+			verbose(env, "invalid%s read from stack R%d off %d+%d size %d\n",
+				err_extra, regno, min_off, i - min_off, access_size);
+		} else {
+			char tn_buf[48];
+
+			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+			verbose(env, "invalid%s read from stack R%d var_off %s+%d size %d\n",
+				err_extra, regno, tn_buf, i - min_off, access_size);
+		}
+		return -EACCES;
+mark:
+		/* reading any byte out of 8-byte 'spill_slot' will cause
+		 * the whole slot to be marked as 'read'
+		 */
+		mark_reg_read(env, &state->stack[spi].spilled_ptr,
+			      state->stack[spi].spilled_ptr.parent,
+			      REG_LIVE_READ64);
+		/* We do not set REG_LIVE_WRITTEN for stack slot, as we can not
+		 * be sure that whether stack slot is written to or not. Hence,
+		 * we must still conservatively propagate reads upwards even if
+		 * helper may write to the entire memory range.
+		 */
+	}
+	return update_stack_depth(env, state, min_off);
+}
+
+static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
+				   int access_size, bool zero_size_allowed,
+				   struct bpf_call_arg_meta *meta)
+{
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	u32 *max_access;
+
+	switch (base_type(reg->type)) {
+	case PTR_TO_PACKET:
+	case PTR_TO_PACKET_META:
+		return check_packet_access(env, regno, reg->off, access_size,
+					   zero_size_allowed);
+	case PTR_TO_MAP_KEY:
+		if (meta && meta->raw_mode) {
+			verbose(env, "R%d cannot write into %s\n", regno,
+				reg_type_str(env, reg->type));
+			return -EACCES;
+		}
+		return check_mem_region_access(env, regno, reg->off, access_size,
+					       reg->map_ptr->key_size, false);
+	case PTR_TO_MAP_VALUE:
+		if (check_map_access_type(env, regno, reg->off, access_size,
+					  meta && meta->raw_mode ? BPF_WRITE :
+					  BPF_READ))
+			return -EACCES;
+		return check_map_access(env, regno, reg->off, access_size,
+					zero_size_allowed, ACCESS_HELPER);
+	case PTR_TO_MEM:
+		if (type_is_rdonly_mem(reg->type)) {
+			if (meta && meta->raw_mode) {
+				verbose(env, "R%d cannot write into %s\n", regno,
+					reg_type_str(env, reg->type));
+				return -EACCES;
+			}
+		}
+		return check_mem_region_access(env, regno, reg->off,
+					       access_size, reg->mem_size,
+					       zero_size_allowed);
+	case PTR_TO_BUF:
+		if (type_is_rdonly_mem(reg->type)) {
+			if (meta && meta->raw_mode) {
+				verbose(env, "R%d cannot write into %s\n", regno,
+					reg_type_str(env, reg->type));
+				return -EACCES;
+			}
+
+			max_access = &env->prog->aux->max_rdonly_access;
+		} else {
+			max_access = &env->prog->aux->max_rdwr_access;
+		}
+		return check_buffer_access(env, reg, regno, reg->off,
+					   access_size, zero_size_allowed,
+					   max_access);
+	case PTR_TO_STACK:
+		return check_stack_range_initialized(
+				env,
+				regno, reg->off, access_size,
+				zero_size_allowed, ACCESS_HELPER, meta);
+	case PTR_TO_CTX:
+		/* in case the function doesn't know how to access the context,
+		 * (because we are in a program of type SYSCALL for example), we
+		 * can not statically check its size.
+		 * Dynamically check it now.
+		 */
+		if (!env->ops->convert_ctx_access) {
+			enum bpf_access_type atype = meta && meta->raw_mode ? BPF_WRITE : BPF_READ;
+			int offset = access_size - 1;
+
+			/* Allow zero-byte read from PTR_TO_CTX */
+			if (access_size == 0)
+				return zero_size_allowed ? 0 : -EACCES;
+
+			return check_mem_access(env, env->insn_idx, regno, offset, BPF_B,
+						atype, -1, false);
+		}
+
+		fallthrough;
+	default: /* scalar_value or invalid ptr */
+		/* Allow zero-byte read from NULL, regardless of pointer type */
+		if (zero_size_allowed && access_size == 0 &&
+		    register_is_null(reg))
+			return 0;
+
+		verbose(env, "R%d type=%s ", regno,
+			reg_type_str(env, reg->type));
+		verbose(env, "expected=%s\n", reg_type_str(env, PTR_TO_STACK));
+		return -EACCES;
+	}
+}
+
+static int check_mem_size_reg(struct bpf_verifier_env *env,
+			      struct bpf_reg_state *reg, u32 regno,
+			      bool zero_size_allowed,
+			      struct bpf_call_arg_meta *meta)
+{
+	int err;
+
+	/* This is used to refine r0 return value bounds for helpers
+	 * that enforce this value as an upper bound on return values.
+	 * See do_refine_retval_range() for helpers that can refine
+	 * the return value. C type of helper is u32 so we pull register
+	 * bound from umax_value however, if negative verifier errors
+	 * out. Only upper bounds can be learned because retval is an
+	 * int type and negative retvals are allowed.
+	 */
+	meta->msize_max_value = reg->umax_value;
+
+	/* The register is SCALAR_VALUE; the access check
+	 * happens using its boundaries.
+	 */
+	if (!tnum_is_const(reg->var_off))
+		/* For unprivileged variable accesses, disable raw
+		 * mode so that the program is required to
+		 * initialize all the memory that the helper could
+		 * just partially fill up.
+		 */
+		meta = NULL;
+
+	if (reg->smin_value < 0) {
+		verbose(env, "R%d min value is negative, either use unsigned or 'var &= const'\n",
+			regno);
+		return -EACCES;
+	}
+
+	if (reg->umin_value == 0) {
+		err = check_helper_mem_access(env, regno - 1, 0,
+					      zero_size_allowed,
+					      meta);
+		if (err)
+			return err;
+	}
+
+	if (reg->umax_value >= BPF_MAX_VAR_SIZ) {
+		verbose(env, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n",
+			regno);
+		return -EACCES;
+	}
+	err = check_helper_mem_access(env, regno - 1,
+				      reg->umax_value,
+				      zero_size_allowed, meta);
+	if (!err)
+		err = mark_chain_precision(env, regno);
+	return err;
+}
+
+int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+		   u32 regno, u32 mem_size)
+{
+	bool may_be_null = type_may_be_null(reg->type);
+	struct bpf_reg_state saved_reg;
+	struct bpf_call_arg_meta meta;
+	int err;
+
+	if (register_is_null(reg))
+		return 0;
+
+	memset(&meta, 0, sizeof(meta));
+	/* Assuming that the register contains a value check if the memory
+	 * access is safe. Temporarily save and restore the register's state as
+	 * the conversion shouldn't be visible to a caller.
+	 */
+	if (may_be_null) {
+		saved_reg = *reg;
+		mark_ptr_not_null_reg(reg);
+	}
+
+	err = check_helper_mem_access(env, regno, mem_size, true, &meta);
+	/* Check access for BPF_WRITE */
+	meta.raw_mode = true;
+	err = err ?: check_helper_mem_access(env, regno, mem_size, true, &meta);
+
+	if (may_be_null)
+		*reg = saved_reg;
+
+	return err;
+}
+
+int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+			     u32 regno)
+{
+	struct bpf_reg_state *mem_reg = &cur_regs(env)[regno - 1];
+	bool may_be_null = type_may_be_null(mem_reg->type);
+	struct bpf_reg_state saved_reg;
+	struct bpf_call_arg_meta meta;
+	int err;
+
+	WARN_ON_ONCE(regno < BPF_REG_2 || regno > BPF_REG_5);
+
+	memset(&meta, 0, sizeof(meta));
+
+	if (may_be_null) {
+		saved_reg = *mem_reg;
+		mark_ptr_not_null_reg(mem_reg);
+	}
+
+	err = check_mem_size_reg(env, reg, regno, true, &meta);
+	/* Check access for BPF_WRITE */
+	meta.raw_mode = true;
+	err = err ?: check_mem_size_reg(env, reg, regno, true, &meta);
+
+	if (may_be_null)
+		*mem_reg = saved_reg;
+	return err;
+}
+
+/* Implementation details:
+ * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL
+ * Two bpf_map_lookups (even with the same key) will have different reg->id.
+ * For traditional PTR_TO_MAP_VALUE the verifier clears reg->id after
+ * value_or_null->value transition, since the verifier only cares about
+ * the range of access to valid map value pointer and doesn't care about actual
+ * address of the map element.
+ * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps
+ * reg->id > 0 after value_or_null->value transition. By doing so
+ * two bpf_map_lookups will be considered two different pointers that
+ * point to different bpf_spin_locks.
+ * The verifier allows taking only one bpf_spin_lock at a time to avoid
+ * dead-locks.
+ * Since only one bpf_spin_lock is allowed the checks are simpler than
+ * reg_is_refcounted() logic. The verifier needs to remember only
+ * one spin_lock instead of array of acquired_refs.
+ * cur_state->active_spin_lock remembers which map value element got locked
+ * and clears it after bpf_spin_unlock.
+ */
+static int process_spin_lock(struct bpf_verifier_env *env, int regno,
+			     bool is_lock)
+{
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_verifier_state *cur = env->cur_state;
+	bool is_const = tnum_is_const(reg->var_off);
+	struct bpf_map *map = reg->map_ptr;
+	u64 val = reg->var_off.value;
+
+	if (!is_const) {
+		verbose(env,
+			"R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n",
+			regno);
+		return -EINVAL;
+	}
+	if (!map->btf) {
+		verbose(env,
+			"map '%s' has to have BTF in order to use bpf_spin_lock\n",
+			map->name);
+		return -EINVAL;
+	}
+	if (!map_value_has_spin_lock(map)) {
+		if (map->spin_lock_off == -E2BIG)
+			verbose(env,
+				"map '%s' has more than one 'struct bpf_spin_lock'\n",
+				map->name);
+		else if (map->spin_lock_off == -ENOENT)
+			verbose(env,
+				"map '%s' doesn't have 'struct bpf_spin_lock'\n",
+				map->name);
+		else
+			verbose(env,
+				"map '%s' is not a struct type or bpf_spin_lock is mangled\n",
+				map->name);
+		return -EINVAL;
+	}
+	if (map->spin_lock_off != val + reg->off) {
+		verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock'\n",
+			val + reg->off);
+		return -EINVAL;
+	}
+	if (is_lock) {
+		if (cur->active_spin_lock) {
+			verbose(env,
+				"Locking two bpf_spin_locks are not allowed\n");
+			return -EINVAL;
+		}
+		cur->active_spin_lock = reg->id;
+	} else {
+		if (!cur->active_spin_lock) {
+			verbose(env, "bpf_spin_unlock without taking a lock\n");
+			return -EINVAL;
+		}
+		if (cur->active_spin_lock != reg->id) {
+			verbose(env, "bpf_spin_unlock of different lock\n");
+			return -EINVAL;
+		}
+		cur->active_spin_lock = 0;
+	}
+	return 0;
+}
+
+static int process_timer_func(struct bpf_verifier_env *env, int regno,
+			      struct bpf_call_arg_meta *meta)
+{
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	bool is_const = tnum_is_const(reg->var_off);
+	struct bpf_map *map = reg->map_ptr;
+	u64 val = reg->var_off.value;
+
+	if (!is_const) {
+		verbose(env,
+			"R%d doesn't have constant offset. bpf_timer has to be at the constant offset\n",
+			regno);
+		return -EINVAL;
+	}
+	if (!map->btf) {
+		verbose(env, "map '%s' has to have BTF in order to use bpf_timer\n",
+			map->name);
+		return -EINVAL;
+	}
+	if (!map_value_has_timer(map)) {
+		if (map->timer_off == -E2BIG)
+			verbose(env,
+				"map '%s' has more than one 'struct bpf_timer'\n",
+				map->name);
+		else if (map->timer_off == -ENOENT)
+			verbose(env,
+				"map '%s' doesn't have 'struct bpf_timer'\n",
+				map->name);
+		else
+			verbose(env,
+				"map '%s' is not a struct type or bpf_timer is mangled\n",
+				map->name);
+		return -EINVAL;
+	}
+	if (map->timer_off != val + reg->off) {
+		verbose(env, "off %lld doesn't point to 'struct bpf_timer' that is at %d\n",
+			val + reg->off, map->timer_off);
+		return -EINVAL;
+	}
+	if (meta->map_ptr) {
+		verbose(env, "verifier bug. Two map pointers in a timer helper\n");
+		return -EFAULT;
+	}
+	meta->map_uid = reg->map_uid;
+	meta->map_ptr = map;
+	return 0;
+}
+
+static int process_kptr_func(struct bpf_verifier_env *env, int regno,
+			     struct bpf_call_arg_meta *meta)
+{
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_map_value_off_desc *off_desc;
+	struct bpf_map *map_ptr = reg->map_ptr;
+	u32 kptr_off;
+	int ret;
+
+	if (!tnum_is_const(reg->var_off)) {
+		verbose(env,
+			"R%d doesn't have constant offset. kptr has to be at the constant offset\n",
+			regno);
+		return -EINVAL;
+	}
+	if (!map_ptr->btf) {
+		verbose(env, "map '%s' has to have BTF in order to use bpf_kptr_xchg\n",
+			map_ptr->name);
+		return -EINVAL;
+	}
+	if (!map_value_has_kptrs(map_ptr)) {
+		ret = PTR_ERR_OR_ZERO(map_ptr->kptr_off_tab);
+		if (ret == -E2BIG)
+			verbose(env, "map '%s' has more than %d kptr\n", map_ptr->name,
+				BPF_MAP_VALUE_OFF_MAX);
+		else if (ret == -EEXIST)
+			verbose(env, "map '%s' has repeating kptr BTF tags\n", map_ptr->name);
+		else
+			verbose(env, "map '%s' has no valid kptr\n", map_ptr->name);
+		return -EINVAL;
+	}
+
+	meta->map_ptr = map_ptr;
+	kptr_off = reg->off + reg->var_off.value;
+	off_desc = bpf_map_kptr_off_contains(map_ptr, kptr_off);
+	if (!off_desc) {
+		verbose(env, "off=%d doesn't point to kptr\n", kptr_off);
+		return -EACCES;
+	}
+	if (off_desc->type != BPF_KPTR_REF) {
+		verbose(env, "off=%d kptr isn't referenced kptr\n", kptr_off);
+		return -EACCES;
+	}
+	meta->kptr_off_desc = off_desc;
+	return 0;
+}
+
+static bool arg_type_is_mem_size(enum bpf_arg_type type)
+{
+	return type == ARG_CONST_SIZE ||
+	       type == ARG_CONST_SIZE_OR_ZERO;
+}
+
+static bool arg_type_is_release(enum bpf_arg_type type)
+{
+	return type & OBJ_RELEASE;
+}
+
+static bool arg_type_is_dynptr(enum bpf_arg_type type)
+{
+	return base_type(type) == ARG_PTR_TO_DYNPTR;
+}
+
+static int int_ptr_type_to_size(enum bpf_arg_type type)
+{
+	if (type == ARG_PTR_TO_INT)
+		return sizeof(u32);
+	else if (type == ARG_PTR_TO_LONG)
+		return sizeof(u64);
+
+	return -EINVAL;
+}
+
+static int resolve_map_arg_type(struct bpf_verifier_env *env,
+				 const struct bpf_call_arg_meta *meta,
+				 enum bpf_arg_type *arg_type)
+{
+	if (!meta->map_ptr) {
+		/* kernel subsystem misconfigured verifier */
+		verbose(env, "invalid map_ptr to access map->type\n");
+		return -EACCES;
+	}
+
+	switch (meta->map_ptr->map_type) {
+	case BPF_MAP_TYPE_SOCKMAP:
+	case BPF_MAP_TYPE_SOCKHASH:
+		if (*arg_type == ARG_PTR_TO_MAP_VALUE) {
+			*arg_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON;
+		} else {
+			verbose(env, "invalid arg_type for sockmap/sockhash\n");
+			return -EINVAL;
+		}
+		break;
+	case BPF_MAP_TYPE_BLOOM_FILTER:
+		if (meta->func_id == BPF_FUNC_map_peek_elem)
+			*arg_type = ARG_PTR_TO_MAP_VALUE;
+		break;
+	default:
+		break;
+	}
+	return 0;
+}
+
+struct bpf_reg_types {
+	const enum bpf_reg_type types[10];
+	u32 *btf_id;
+};
+
+static const struct bpf_reg_types map_key_value_types = {
+	.types = {
+		PTR_TO_STACK,
+		PTR_TO_PACKET,
+		PTR_TO_PACKET_META,
+		PTR_TO_MAP_KEY,
+		PTR_TO_MAP_VALUE,
+	},
+};
+
+static const struct bpf_reg_types sock_types = {
+	.types = {
+		PTR_TO_SOCK_COMMON,
+		PTR_TO_SOCKET,
+		PTR_TO_TCP_SOCK,
+		PTR_TO_XDP_SOCK,
+	},
+};
+
+#ifdef CONFIG_NET
+static const struct bpf_reg_types btf_id_sock_common_types = {
+	.types = {
+		PTR_TO_SOCK_COMMON,
+		PTR_TO_SOCKET,
+		PTR_TO_TCP_SOCK,
+		PTR_TO_XDP_SOCK,
+		PTR_TO_BTF_ID,
+	},
+	.btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
+};
+#endif
+
+static const struct bpf_reg_types mem_types = {
+	.types = {
+		PTR_TO_STACK,
+		PTR_TO_PACKET,
+		PTR_TO_PACKET_META,
+		PTR_TO_MAP_KEY,
+		PTR_TO_MAP_VALUE,
+		PTR_TO_MEM,
+		PTR_TO_MEM | MEM_ALLOC,
+		PTR_TO_BUF,
+	},
+};
+
+static const struct bpf_reg_types int_ptr_types = {
+	.types = {
+		PTR_TO_STACK,
+		PTR_TO_PACKET,
+		PTR_TO_PACKET_META,
+		PTR_TO_MAP_KEY,
+		PTR_TO_MAP_VALUE,
+	},
+};
+
+static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } };
+static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } };
+static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } };
+static const struct bpf_reg_types alloc_mem_types = { .types = { PTR_TO_MEM | MEM_ALLOC } };
+static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } };
+static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } };
+static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } };
+static const struct bpf_reg_types percpu_btf_ptr_types = { .types = { PTR_TO_BTF_ID | MEM_PERCPU } };
+static const struct bpf_reg_types func_ptr_types = { .types = { PTR_TO_FUNC } };
+static const struct bpf_reg_types stack_ptr_types = { .types = { PTR_TO_STACK } };
+static const struct bpf_reg_types const_str_ptr_types = { .types = { PTR_TO_MAP_VALUE } };
+static const struct bpf_reg_types timer_types = { .types = { PTR_TO_MAP_VALUE } };
+static const struct bpf_reg_types kptr_types = { .types = { PTR_TO_MAP_VALUE } };
+static const struct bpf_reg_types dynptr_types = {
+	.types = {
+		PTR_TO_STACK,
+		PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL,
+	}
+};
+
+static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = {
+	[ARG_PTR_TO_MAP_KEY]		= &map_key_value_types,
+	[ARG_PTR_TO_MAP_VALUE]		= &map_key_value_types,
+	[ARG_CONST_SIZE]		= &scalar_types,
+	[ARG_CONST_SIZE_OR_ZERO]	= &scalar_types,
+	[ARG_CONST_ALLOC_SIZE_OR_ZERO]	= &scalar_types,
+	[ARG_CONST_MAP_PTR]		= &const_map_ptr_types,
+	[ARG_PTR_TO_CTX]		= &context_types,
+	[ARG_PTR_TO_SOCK_COMMON]	= &sock_types,
+#ifdef CONFIG_NET
+	[ARG_PTR_TO_BTF_ID_SOCK_COMMON]	= &btf_id_sock_common_types,
+#endif
+	[ARG_PTR_TO_SOCKET]		= &fullsock_types,
+	[ARG_PTR_TO_BTF_ID]		= &btf_ptr_types,
+	[ARG_PTR_TO_SPIN_LOCK]		= &spin_lock_types,
+	[ARG_PTR_TO_MEM]		= &mem_types,
+	[ARG_PTR_TO_ALLOC_MEM]		= &alloc_mem_types,
+	[ARG_PTR_TO_INT]		= &int_ptr_types,
+	[ARG_PTR_TO_LONG]		= &int_ptr_types,
+	[ARG_PTR_TO_PERCPU_BTF_ID]	= &percpu_btf_ptr_types,
+	[ARG_PTR_TO_FUNC]		= &func_ptr_types,
+	[ARG_PTR_TO_STACK]		= &stack_ptr_types,
+	[ARG_PTR_TO_CONST_STR]		= &const_str_ptr_types,
+	[ARG_PTR_TO_TIMER]		= &timer_types,
+	[ARG_PTR_TO_KPTR]		= &kptr_types,
+	[ARG_PTR_TO_DYNPTR]		= &dynptr_types,
+};
+
+static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
+			  enum bpf_arg_type arg_type,
+			  const u32 *arg_btf_id,
+			  struct bpf_call_arg_meta *meta)
+{
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	enum bpf_reg_type expected, type = reg->type;
+	const struct bpf_reg_types *compatible;
+	int i, j;
+
+	compatible = compatible_reg_types[base_type(arg_type)];
+	if (!compatible) {
+		verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type);
+		return -EFAULT;
+	}
+
+	/* ARG_PTR_TO_MEM + RDONLY is compatible with PTR_TO_MEM and PTR_TO_MEM + RDONLY,
+	 * but ARG_PTR_TO_MEM is compatible only with PTR_TO_MEM and NOT with PTR_TO_MEM + RDONLY
+	 *
+	 * Same for MAYBE_NULL:
+	 *
+	 * ARG_PTR_TO_MEM + MAYBE_NULL is compatible with PTR_TO_MEM and PTR_TO_MEM + MAYBE_NULL,
+	 * but ARG_PTR_TO_MEM is compatible only with PTR_TO_MEM but NOT with PTR_TO_MEM + MAYBE_NULL
+	 *
+	 * Therefore we fold these flags depending on the arg_type before comparison.
+	 */
+	if (arg_type & MEM_RDONLY)
+		type &= ~MEM_RDONLY;
+	if (arg_type & PTR_MAYBE_NULL)
+		type &= ~PTR_MAYBE_NULL;
+
+	for (i = 0; i < ARRAY_SIZE(compatible->types); i++) {
+		expected = compatible->types[i];
+		if (expected == NOT_INIT)
+			break;
+
+		if (type == expected)
+			goto found;
+	}
+
+	verbose(env, "R%d type=%s expected=", regno, reg_type_str(env, reg->type));
+	for (j = 0; j + 1 < i; j++)
+		verbose(env, "%s, ", reg_type_str(env, compatible->types[j]));
+	verbose(env, "%s\n", reg_type_str(env, compatible->types[j]));
+	return -EACCES;
+
+found:
+	if (reg->type == PTR_TO_BTF_ID) {
+		/* For bpf_sk_release, it needs to match against first member
+		 * 'struct sock_common', hence make an exception for it. This
+		 * allows bpf_sk_release to work for multiple socket types.
+		 */
+		bool strict_type_match = arg_type_is_release(arg_type) &&
+					 meta->func_id != BPF_FUNC_sk_release;
+
+		if (!arg_btf_id) {
+			if (!compatible->btf_id) {
+				verbose(env, "verifier internal error: missing arg compatible BTF ID\n");
+				return -EFAULT;
+			}
+			arg_btf_id = compatible->btf_id;
+		}
+
+		if (meta->func_id == BPF_FUNC_kptr_xchg) {
+			if (map_kptr_match_type(env, meta->kptr_off_desc, reg, regno))
+				return -EACCES;
+		} else {
+			if (arg_btf_id == BPF_PTR_POISON) {
+				verbose(env, "verifier internal error:");
+				verbose(env, "R%d has non-overwritten BPF_PTR_POISON type\n",
+					regno);
+				return -EACCES;
+			}
+
+			if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off,
+						  btf_vmlinux, *arg_btf_id,
+						  strict_type_match)) {
+				verbose(env, "R%d is of type %s but %s is expected\n",
+					regno, kernel_type_name(reg->btf, reg->btf_id),
+					kernel_type_name(btf_vmlinux, *arg_btf_id));
+				return -EACCES;
+			}
+		}
+	}
+
+	return 0;
+}
+
+int check_func_arg_reg_off(struct bpf_verifier_env *env,
+			   const struct bpf_reg_state *reg, int regno,
+			   enum bpf_arg_type arg_type)
+{
+	enum bpf_reg_type type = reg->type;
+	bool fixed_off_ok = false;
+
+	switch ((u32)type) {
+	/* Pointer types where reg offset is explicitly allowed: */
+	case PTR_TO_STACK:
+		if (arg_type_is_dynptr(arg_type) && reg->off % BPF_REG_SIZE) {
+			verbose(env, "cannot pass in dynptr at an offset\n");
+			return -EINVAL;
+		}
+		fallthrough;
+	case PTR_TO_PACKET:
+	case PTR_TO_PACKET_META:
+	case PTR_TO_MAP_KEY:
+	case PTR_TO_MAP_VALUE:
+	case PTR_TO_MEM:
+	case PTR_TO_MEM | MEM_RDONLY:
+	case PTR_TO_MEM | MEM_ALLOC:
+	case PTR_TO_BUF:
+	case PTR_TO_BUF | MEM_RDONLY:
+	case SCALAR_VALUE:
+		/* Some of the argument types nevertheless require a
+		 * zero register offset.
+		 */
+		if (base_type(arg_type) != ARG_PTR_TO_ALLOC_MEM)
+			return 0;
+		break;
+	/* All the rest must be rejected, except PTR_TO_BTF_ID which allows
+	 * fixed offset.
+	 */
+	case PTR_TO_BTF_ID:
+		/* When referenced PTR_TO_BTF_ID is passed to release function,
+		 * it's fixed offset must be 0.	In the other cases, fixed offset
+		 * can be non-zero.
+		 */
+		if (arg_type_is_release(arg_type) && reg->off) {
+			verbose(env, "R%d must have zero offset when passed to release func\n",
+				regno);
+			return -EINVAL;
+		}
+		/* For arg is release pointer, fixed_off_ok must be false, but
+		 * we already checked and rejected reg->off != 0 above, so set
+		 * to true to allow fixed offset for all other cases.
+		 */
+		fixed_off_ok = true;
+		break;
+	default:
+		break;
+	}
+	return __check_ptr_off_reg(env, reg, regno, fixed_off_ok);
+}
+
+static u32 stack_slot_get_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi = get_spi(reg->off);
+
+	return state->stack[spi].spilled_ptr.id;
+}
+
+static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
+			  struct bpf_call_arg_meta *meta,
+			  const struct bpf_func_proto *fn)
+{
+	u32 regno = BPF_REG_1 + arg;
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	enum bpf_arg_type arg_type = fn->arg_type[arg];
+	enum bpf_reg_type type = reg->type;
+	u32 *arg_btf_id = NULL;
+	int err = 0;
+
+	if (arg_type == ARG_DONTCARE)
+		return 0;
+
+	err = check_reg_arg(env, regno, SRC_OP);
+	if (err)
+		return err;
+
+	if (arg_type == ARG_ANYTHING) {
+		if (is_pointer_value(env, regno)) {
+			verbose(env, "R%d leaks addr into helper function\n",
+				regno);
+			return -EACCES;
+		}
+		return 0;
+	}
+
+	if (type_is_pkt_pointer(type) &&
+	    !may_access_direct_pkt_data(env, meta, BPF_READ)) {
+		verbose(env, "helper access to the packet is not allowed\n");
+		return -EACCES;
+	}
+
+	if (base_type(arg_type) == ARG_PTR_TO_MAP_VALUE) {
+		err = resolve_map_arg_type(env, meta, &arg_type);
+		if (err)
+			return err;
+	}
+
+	if (register_is_null(reg) && type_may_be_null(arg_type))
+		/* A NULL register has a SCALAR_VALUE type, so skip
+		 * type checking.
+		 */
+		goto skip_type_check;
+
+	/* arg_btf_id and arg_size are in a union. */
+	if (base_type(arg_type) == ARG_PTR_TO_BTF_ID)
+		arg_btf_id = fn->arg_btf_id[arg];
+
+	err = check_reg_type(env, regno, arg_type, arg_btf_id, meta);
+	if (err)
+		return err;
+
+	err = check_func_arg_reg_off(env, reg, regno, arg_type);
+	if (err)
+		return err;
+
+skip_type_check:
+	if (arg_type_is_release(arg_type)) {
+		if (arg_type_is_dynptr(arg_type)) {
+			struct bpf_func_state *state = func(env, reg);
+			int spi = get_spi(reg->off);
+
+			if (!is_spi_bounds_valid(state, spi, BPF_DYNPTR_NR_SLOTS) ||
+			    !state->stack[spi].spilled_ptr.id) {
+				verbose(env, "arg %d is an unacquired reference\n", regno);
+				return -EINVAL;
+			}
+		} else if (!reg->ref_obj_id && !register_is_null(reg)) {
+			verbose(env, "R%d must be referenced when passed to release function\n",
+				regno);
+			return -EINVAL;
+		}
+		if (meta->release_regno) {
+			verbose(env, "verifier internal error: more than one release argument\n");
+			return -EFAULT;
+		}
+		meta->release_regno = regno;
+	}
+
+	if (reg->ref_obj_id) {
+		if (meta->ref_obj_id) {
+			verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
+				regno, reg->ref_obj_id,
+				meta->ref_obj_id);
+			return -EFAULT;
+		}
+		meta->ref_obj_id = reg->ref_obj_id;
+	}
+
+	switch (base_type(arg_type)) {
+	case ARG_CONST_MAP_PTR:
+		/* bpf_map_xxx(map_ptr) call: remember that map_ptr */
+		if (meta->map_ptr) {
+			/* Use map_uid (which is unique id of inner map) to reject:
+			 * inner_map1 = bpf_map_lookup_elem(outer_map, key1)
+			 * inner_map2 = bpf_map_lookup_elem(outer_map, key2)
+			 * if (inner_map1 && inner_map2) {
+			 *     timer = bpf_map_lookup_elem(inner_map1);
+			 *     if (timer)
+			 *         // mismatch would have been allowed
+			 *         bpf_timer_init(timer, inner_map2);
+			 * }
+			 *
+			 * Comparing map_ptr is enough to distinguish normal and outer maps.
+			 */
+			if (meta->map_ptr != reg->map_ptr ||
+			    meta->map_uid != reg->map_uid) {
+				verbose(env,
+					"timer pointer in R1 map_uid=%d doesn't match map pointer in R2 map_uid=%d\n",
+					meta->map_uid, reg->map_uid);
+				return -EINVAL;
+			}
+		}
+		meta->map_ptr = reg->map_ptr;
+		meta->map_uid = reg->map_uid;
+		break;
+	case ARG_PTR_TO_MAP_KEY:
+		/* bpf_map_xxx(..., map_ptr, ..., key) call:
+		 * check that [key, key + map->key_size) are within
+		 * stack limits and initialized
+		 */
+		if (!meta->map_ptr) {
+			/* in function declaration map_ptr must come before
+			 * map_key, so that it's verified and known before
+			 * we have to check map_key here. Otherwise it means
+			 * that kernel subsystem misconfigured verifier
+			 */
+			verbose(env, "invalid map_ptr to access map->key\n");
+			return -EACCES;
+		}
+		err = check_helper_mem_access(env, regno,
+					      meta->map_ptr->key_size, false,
+					      NULL);
+		break;
+	case ARG_PTR_TO_MAP_VALUE:
+		if (type_may_be_null(arg_type) && register_is_null(reg))
+			return 0;
+
+		/* bpf_map_xxx(..., map_ptr, ..., value) call:
+		 * check [value, value + map->value_size) validity
+		 */
+		if (!meta->map_ptr) {
+			/* kernel subsystem misconfigured verifier */
+			verbose(env, "invalid map_ptr to access map->value\n");
+			return -EACCES;
+		}
+		meta->raw_mode = arg_type & MEM_UNINIT;
+		err = check_helper_mem_access(env, regno,
+					      meta->map_ptr->value_size, false,
+					      meta);
+		break;
+	case ARG_PTR_TO_PERCPU_BTF_ID:
+		if (!reg->btf_id) {
+			verbose(env, "Helper has invalid btf_id in R%d\n", regno);
+			return -EACCES;
+		}
+		meta->ret_btf = reg->btf;
+		meta->ret_btf_id = reg->btf_id;
+		break;
+	case ARG_PTR_TO_SPIN_LOCK:
+		if (meta->func_id == BPF_FUNC_spin_lock) {
+			if (process_spin_lock(env, regno, true))
+				return -EACCES;
+		} else if (meta->func_id == BPF_FUNC_spin_unlock) {
+			if (process_spin_lock(env, regno, false))
+				return -EACCES;
+		} else {
+			verbose(env, "verifier internal error\n");
+			return -EFAULT;
+		}
+		break;
+	case ARG_PTR_TO_TIMER:
+		if (process_timer_func(env, regno, meta))
+			return -EACCES;
+		break;
+	case ARG_PTR_TO_FUNC:
+		meta->subprogno = reg->subprogno;
+		break;
+	case ARG_PTR_TO_MEM:
+		/* The access to this pointer is only checked when we hit the
+		 * next is_mem_size argument below.
+		 */
+		meta->raw_mode = arg_type & MEM_UNINIT;
+		if (arg_type & MEM_FIXED_SIZE) {
+			err = check_helper_mem_access(env, regno,
+						      fn->arg_size[arg], false,
+						      meta);
+		}
+		break;
+	case ARG_CONST_SIZE:
+		err = check_mem_size_reg(env, reg, regno, false, meta);
+		break;
+	case ARG_CONST_SIZE_OR_ZERO:
+		err = check_mem_size_reg(env, reg, regno, true, meta);
+		break;
+	case ARG_PTR_TO_DYNPTR:
+		/* We only need to check for initialized / uninitialized helper
+		 * dynptr args if the dynptr is not PTR_TO_DYNPTR, as the
+		 * assumption is that if it is, that a helper function
+		 * initialized the dynptr on behalf of the BPF program.
+		 */
+		if (base_type(reg->type) == PTR_TO_DYNPTR)
+			break;
+		if (arg_type & MEM_UNINIT) {
+			if (!is_dynptr_reg_valid_uninit(env, reg)) {
+				verbose(env, "Dynptr has to be an uninitialized dynptr\n");
+				return -EINVAL;
+			}
+
+			/* We only support one dynptr being uninitialized at the moment,
+			 * which is sufficient for the helper functions we have right now.
+			 */
+			if (meta->uninit_dynptr_regno) {
+				verbose(env, "verifier internal error: multiple uninitialized dynptr args\n");
+				return -EFAULT;
+			}
+
+			meta->uninit_dynptr_regno = regno;
+		} else if (!is_dynptr_reg_valid_init(env, reg)) {
+			verbose(env,
+				"Expected an initialized dynptr as arg #%d\n",
+				arg + 1);
+			return -EINVAL;
+		} else if (!is_dynptr_type_expected(env, reg, arg_type)) {
+			const char *err_extra = "";
+
+			switch (arg_type & DYNPTR_TYPE_FLAG_MASK) {
+			case DYNPTR_TYPE_LOCAL:
+				err_extra = "local";
+				break;
+			case DYNPTR_TYPE_RINGBUF:
+				err_extra = "ringbuf";
+				break;
+			default:
+				err_extra = "<unknown>";
+				break;
+			}
+			verbose(env,
+				"Expected a dynptr of type %s as arg #%d\n",
+				err_extra, arg + 1);
+			return -EINVAL;
+		}
+		break;
+	case ARG_CONST_ALLOC_SIZE_OR_ZERO:
+		if (!tnum_is_const(reg->var_off)) {
+			verbose(env, "R%d is not a known constant'\n",
+				regno);
+			return -EACCES;
+		}
+		meta->mem_size = reg->var_off.value;
+		err = mark_chain_precision(env, regno);
+		if (err)
+			return err;
+		break;
+	case ARG_PTR_TO_INT:
+	case ARG_PTR_TO_LONG:
+	{
+		int size = int_ptr_type_to_size(arg_type);
+
+		err = check_helper_mem_access(env, regno, size, false, meta);
+		if (err)
+			return err;
+		err = check_ptr_alignment(env, reg, 0, size, true);
+		break;
+	}
+	case ARG_PTR_TO_CONST_STR:
+	{
+		struct bpf_map *map = reg->map_ptr;
+		int map_off;
+		u64 map_addr;
+		char *str_ptr;
+
+		if (!bpf_map_is_rdonly(map)) {
+			verbose(env, "R%d does not point to a readonly map'\n", regno);
+			return -EACCES;
+		}
+
+		if (!tnum_is_const(reg->var_off)) {
+			verbose(env, "R%d is not a constant address'\n", regno);
+			return -EACCES;
+		}
+
+		if (!map->ops->map_direct_value_addr) {
+			verbose(env, "no direct value access support for this map type\n");
+			return -EACCES;
+		}
+
+		err = check_map_access(env, regno, reg->off,
+				       map->value_size - reg->off, false,
+				       ACCESS_HELPER);
+		if (err)
+			return err;
+
+		map_off = reg->off + reg->var_off.value;
+		err = map->ops->map_direct_value_addr(map, &map_addr, map_off);
+		if (err) {
+			verbose(env, "direct value access on string failed\n");
+			return err;
+		}
+
+		str_ptr = (char *)(long)(map_addr);
+		if (!strnchr(str_ptr + map_off, map->value_size - map_off, 0)) {
+			verbose(env, "string is not zero-terminated\n");
+			return -EINVAL;
+		}
+		break;
+	}
+	case ARG_PTR_TO_KPTR:
+		if (process_kptr_func(env, regno, meta))
+			return -EACCES;
+		break;
+	}
+
+	return err;
+}
+
+static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id)
+{
+	enum bpf_attach_type eatype = env->prog->expected_attach_type;
+	enum bpf_prog_type type = resolve_prog_type(env->prog);
+
+	if (func_id != BPF_FUNC_map_update_elem)
+		return false;
+
+	/* It's not possible to get access to a locked struct sock in these
+	 * contexts, so updating is safe.
+	 */
+	switch (type) {
+	case BPF_PROG_TYPE_TRACING:
+		if (eatype == BPF_TRACE_ITER)
+			return true;
+		break;
+	case BPF_PROG_TYPE_SOCKET_FILTER:
+	case BPF_PROG_TYPE_SCHED_CLS:
+	case BPF_PROG_TYPE_SCHED_ACT:
+	case BPF_PROG_TYPE_XDP:
+	case BPF_PROG_TYPE_SK_REUSEPORT:
+	case BPF_PROG_TYPE_FLOW_DISSECTOR:
+	case BPF_PROG_TYPE_SK_LOOKUP:
+		return true;
+	default:
+		break;
+	}
+
+	verbose(env, "cannot update sockmap in this context\n");
+	return false;
+}
+
+static bool allow_tail_call_in_subprogs(struct bpf_verifier_env *env)
+{
+	return env->prog->jit_requested &&
+	       bpf_jit_supports_subprog_tailcalls();
+}
+
+static int check_map_func_compatibility(struct bpf_verifier_env *env,
+					struct bpf_map *map, int func_id)
+{
+	if (!map)
+		return 0;
+
+	/* We need a two way check, first is from map perspective ... */
+	switch (map->map_type) {
+	case BPF_MAP_TYPE_PROG_ARRAY:
+		if (func_id != BPF_FUNC_tail_call)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
+		if (func_id != BPF_FUNC_perf_event_read &&
+		    func_id != BPF_FUNC_perf_event_output &&
+		    func_id != BPF_FUNC_skb_output &&
+		    func_id != BPF_FUNC_perf_event_read_value &&
+		    func_id != BPF_FUNC_xdp_output)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_RINGBUF:
+		if (func_id != BPF_FUNC_ringbuf_output &&
+		    func_id != BPF_FUNC_ringbuf_reserve &&
+		    func_id != BPF_FUNC_ringbuf_query &&
+		    func_id != BPF_FUNC_ringbuf_reserve_dynptr &&
+		    func_id != BPF_FUNC_ringbuf_submit_dynptr &&
+		    func_id != BPF_FUNC_ringbuf_discard_dynptr)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_USER_RINGBUF:
+		if (func_id != BPF_FUNC_user_ringbuf_drain)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_STACK_TRACE:
+		if (func_id != BPF_FUNC_get_stackid)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_CGROUP_ARRAY:
+		if (func_id != BPF_FUNC_skb_under_cgroup &&
+		    func_id != BPF_FUNC_current_task_under_cgroup)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_CGROUP_STORAGE:
+	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
+		if (func_id != BPF_FUNC_get_local_storage)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_DEVMAP:
+	case BPF_MAP_TYPE_DEVMAP_HASH:
+		if (func_id != BPF_FUNC_redirect_map &&
+		    func_id != BPF_FUNC_map_lookup_elem)
+			goto error;
+		break;
+	/* Restrict bpf side of cpumap and xskmap, open when use-cases
+	 * appear.
+	 */
+	case BPF_MAP_TYPE_CPUMAP:
+		if (func_id != BPF_FUNC_redirect_map)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_XSKMAP:
+		if (func_id != BPF_FUNC_redirect_map &&
+		    func_id != BPF_FUNC_map_lookup_elem)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+	case BPF_MAP_TYPE_HASH_OF_MAPS:
+		if (func_id != BPF_FUNC_map_lookup_elem)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_SOCKMAP:
+		if (func_id != BPF_FUNC_sk_redirect_map &&
+		    func_id != BPF_FUNC_sock_map_update &&
+		    func_id != BPF_FUNC_map_delete_elem &&
+		    func_id != BPF_FUNC_msg_redirect_map &&
+		    func_id != BPF_FUNC_sk_select_reuseport &&
+		    func_id != BPF_FUNC_map_lookup_elem &&
+		    !may_update_sockmap(env, func_id))
+			goto error;
+		break;
+	case BPF_MAP_TYPE_SOCKHASH:
+		if (func_id != BPF_FUNC_sk_redirect_hash &&
+		    func_id != BPF_FUNC_sock_hash_update &&
+		    func_id != BPF_FUNC_map_delete_elem &&
+		    func_id != BPF_FUNC_msg_redirect_hash &&
+		    func_id != BPF_FUNC_sk_select_reuseport &&
+		    func_id != BPF_FUNC_map_lookup_elem &&
+		    !may_update_sockmap(env, func_id))
+			goto error;
+		break;
+	case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
+		if (func_id != BPF_FUNC_sk_select_reuseport)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_QUEUE:
+	case BPF_MAP_TYPE_STACK:
+		if (func_id != BPF_FUNC_map_peek_elem &&
+		    func_id != BPF_FUNC_map_pop_elem &&
+		    func_id != BPF_FUNC_map_push_elem)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_SK_STORAGE:
+		if (func_id != BPF_FUNC_sk_storage_get &&
+		    func_id != BPF_FUNC_sk_storage_delete)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_INODE_STORAGE:
+		if (func_id != BPF_FUNC_inode_storage_get &&
+		    func_id != BPF_FUNC_inode_storage_delete)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_TASK_STORAGE:
+		if (func_id != BPF_FUNC_task_storage_get &&
+		    func_id != BPF_FUNC_task_storage_delete)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_BLOOM_FILTER:
+		if (func_id != BPF_FUNC_map_peek_elem &&
+		    func_id != BPF_FUNC_map_push_elem)
+			goto error;
+		break;
+	default:
+		break;
+	}
+
+	/* ... and second from the function itself. */
+	switch (func_id) {
+	case BPF_FUNC_tail_call:
+		if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
+			goto error;
+		if (env->subprog_cnt > 1 && !allow_tail_call_in_subprogs(env)) {
+			verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
+			return -EINVAL;
+		}
+		break;
+	case BPF_FUNC_perf_event_read:
+	case BPF_FUNC_perf_event_output:
+	case BPF_FUNC_perf_event_read_value:
+	case BPF_FUNC_skb_output:
+	case BPF_FUNC_xdp_output:
+		if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
+			goto error;
+		break;
+	case BPF_FUNC_ringbuf_output:
+	case BPF_FUNC_ringbuf_reserve:
+	case BPF_FUNC_ringbuf_query:
+	case BPF_FUNC_ringbuf_reserve_dynptr:
+	case BPF_FUNC_ringbuf_submit_dynptr:
+	case BPF_FUNC_ringbuf_discard_dynptr:
+		if (map->map_type != BPF_MAP_TYPE_RINGBUF)
+			goto error;
+		break;
+	case BPF_FUNC_user_ringbuf_drain:
+		if (map->map_type != BPF_MAP_TYPE_USER_RINGBUF)
+			goto error;
+		break;
+	case BPF_FUNC_get_stackid:
+		if (map->map_type != BPF_MAP_TYPE_STACK_TRACE)
+			goto error;
+		break;
+	case BPF_FUNC_current_task_under_cgroup:
+	case BPF_FUNC_skb_under_cgroup:
+		if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY)
+			goto error;
+		break;
+	case BPF_FUNC_redirect_map:
+		if (map->map_type != BPF_MAP_TYPE_DEVMAP &&
+		    map->map_type != BPF_MAP_TYPE_DEVMAP_HASH &&
+		    map->map_type != BPF_MAP_TYPE_CPUMAP &&
+		    map->map_type != BPF_MAP_TYPE_XSKMAP)
+			goto error;
+		break;
+	case BPF_FUNC_sk_redirect_map:
+	case BPF_FUNC_msg_redirect_map:
+	case BPF_FUNC_sock_map_update:
+		if (map->map_type != BPF_MAP_TYPE_SOCKMAP)
+			goto error;
+		break;
+	case BPF_FUNC_sk_redirect_hash:
+	case BPF_FUNC_msg_redirect_hash:
+	case BPF_FUNC_sock_hash_update:
+		if (map->map_type != BPF_MAP_TYPE_SOCKHASH)
+			goto error;
+		break;
+	case BPF_FUNC_get_local_storage:
+		if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
+		    map->map_type != BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
+			goto error;
+		break;
+	case BPF_FUNC_sk_select_reuseport:
+		if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY &&
+		    map->map_type != BPF_MAP_TYPE_SOCKMAP &&
+		    map->map_type != BPF_MAP_TYPE_SOCKHASH)
+			goto error;
+		break;
+	case BPF_FUNC_map_pop_elem:
+		if (map->map_type != BPF_MAP_TYPE_QUEUE &&
+		    map->map_type != BPF_MAP_TYPE_STACK)
+			goto error;
+		break;
+	case BPF_FUNC_map_peek_elem:
+	case BPF_FUNC_map_push_elem:
+		if (map->map_type != BPF_MAP_TYPE_QUEUE &&
+		    map->map_type != BPF_MAP_TYPE_STACK &&
+		    map->map_type != BPF_MAP_TYPE_BLOOM_FILTER)
+			goto error;
+		break;
+	case BPF_FUNC_map_lookup_percpu_elem:
+		if (map->map_type != BPF_MAP_TYPE_PERCPU_ARRAY &&
+		    map->map_type != BPF_MAP_TYPE_PERCPU_HASH &&
+		    map->map_type != BPF_MAP_TYPE_LRU_PERCPU_HASH)
+			goto error;
+		break;
+	case BPF_FUNC_sk_storage_get:
+	case BPF_FUNC_sk_storage_delete:
+		if (map->map_type != BPF_MAP_TYPE_SK_STORAGE)
+			goto error;
+		break;
+	case BPF_FUNC_inode_storage_get:
+	case BPF_FUNC_inode_storage_delete:
+		if (map->map_type != BPF_MAP_TYPE_INODE_STORAGE)
+			goto error;
+		break;
+	case BPF_FUNC_task_storage_get:
+	case BPF_FUNC_task_storage_delete:
+		if (map->map_type != BPF_MAP_TYPE_TASK_STORAGE)
+			goto error;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+error:
+	verbose(env, "cannot pass map_type %d into func %s#%d\n",
+		map->map_type, func_id_name(func_id), func_id);
+	return -EINVAL;
+}
+
+static bool check_raw_mode_ok(const struct bpf_func_proto *fn)
+{
+	int count = 0;
+
+	if (fn->arg1_type == ARG_PTR_TO_UNINIT_MEM)
+		count++;
+	if (fn->arg2_type == ARG_PTR_TO_UNINIT_MEM)
+		count++;
+	if (fn->arg3_type == ARG_PTR_TO_UNINIT_MEM)
+		count++;
+	if (fn->arg4_type == ARG_PTR_TO_UNINIT_MEM)
+		count++;
+	if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM)
+		count++;
+
+	/* We only support one arg being in raw mode at the moment,
+	 * which is sufficient for the helper functions we have
+	 * right now.
+	 */
+	return count <= 1;
+}
+
+static bool check_args_pair_invalid(const struct bpf_func_proto *fn, int arg)
+{
+	bool is_fixed = fn->arg_type[arg] & MEM_FIXED_SIZE;
+	bool has_size = fn->arg_size[arg] != 0;
+	bool is_next_size = false;
+
+	if (arg + 1 < ARRAY_SIZE(fn->arg_type))
+		is_next_size = arg_type_is_mem_size(fn->arg_type[arg + 1]);
+
+	if (base_type(fn->arg_type[arg]) != ARG_PTR_TO_MEM)
+		return is_next_size;
+
+	return has_size == is_next_size || is_next_size == is_fixed;
+}
+
+static bool check_arg_pair_ok(const struct bpf_func_proto *fn)
+{
+	/* bpf_xxx(..., buf, len) call will access 'len'
+	 * bytes from memory 'buf'. Both arg types need
+	 * to be paired, so make sure there's no buggy
+	 * helper function specification.
+	 */
+	if (arg_type_is_mem_size(fn->arg1_type) ||
+	    check_args_pair_invalid(fn, 0) ||
+	    check_args_pair_invalid(fn, 1) ||
+	    check_args_pair_invalid(fn, 2) ||
+	    check_args_pair_invalid(fn, 3) ||
+	    check_args_pair_invalid(fn, 4))
+		return false;
+
+	return true;
+}
+
+static bool check_btf_id_ok(const struct bpf_func_proto *fn)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) {
+		if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID && !fn->arg_btf_id[i])
+			return false;
+
+		if (base_type(fn->arg_type[i]) != ARG_PTR_TO_BTF_ID && fn->arg_btf_id[i] &&
+		    /* arg_btf_id and arg_size are in a union. */
+		    (base_type(fn->arg_type[i]) != ARG_PTR_TO_MEM ||
+		     !(fn->arg_type[i] & MEM_FIXED_SIZE)))
+			return false;
+	}
+
+	return true;
+}
+
+static int check_func_proto(const struct bpf_func_proto *fn, int func_id)
+{
+	return check_raw_mode_ok(fn) &&
+	       check_arg_pair_ok(fn) &&
+	       check_btf_id_ok(fn) ? 0 : -EINVAL;
+}
+
+/* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
+ * are now invalid, so turn them into unknown SCALAR_VALUE.
+ */
+static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
+{
+	struct bpf_func_state *state;
+	struct bpf_reg_state *reg;
+
+	bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
+		if (reg_is_pkt_pointer_any(reg))
+			__mark_reg_unknown(env, reg);
+	}));
+}
+
+enum {
+	AT_PKT_END = -1,
+	BEYOND_PKT_END = -2,
+};
+
+static void mark_pkt_end(struct bpf_verifier_state *vstate, int regn, bool range_open)
+{
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_reg_state *reg = &state->regs[regn];
+
+	if (reg->type != PTR_TO_PACKET)
+		/* PTR_TO_PACKET_META is not supported yet */
+		return;
+
+	/* The 'reg' is pkt > pkt_end or pkt >= pkt_end.
+	 * How far beyond pkt_end it goes is unknown.
+	 * if (!range_open) it's the case of pkt >= pkt_end
+	 * if (range_open) it's the case of pkt > pkt_end
+	 * hence this pointer is at least 1 byte bigger than pkt_end
+	 */
+	if (range_open)
+		reg->range = BEYOND_PKT_END;
+	else
+		reg->range = AT_PKT_END;
+}
+
+/* The pointer with the specified id has released its reference to kernel
+ * resources. Identify all copies of the same pointer and clear the reference.
+ */
+static int release_reference(struct bpf_verifier_env *env,
+			     int ref_obj_id)
+{
+	struct bpf_func_state *state;
+	struct bpf_reg_state *reg;
+	int err;
+
+	err = release_reference_state(cur_func(env), ref_obj_id);
+	if (err)
+		return err;
+
+	bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
+		if (reg->ref_obj_id == ref_obj_id) {
+			if (!env->allow_ptr_leaks)
+				__mark_reg_not_init(env, reg);
+			else
+				__mark_reg_unknown(env, reg);
+		}
+	}));
+
+	return 0;
+}
+
+static void clear_caller_saved_regs(struct bpf_verifier_env *env,
+				    struct bpf_reg_state *regs)
+{
+	int i;
+
+	/* after the call registers r0 - r5 were scratched */
+	for (i = 0; i < CALLER_SAVED_REGS; i++) {
+		mark_reg_not_init(env, regs, caller_saved[i]);
+		check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+	}
+}
+
+typedef int (*set_callee_state_fn)(struct bpf_verifier_env *env,
+				   struct bpf_func_state *caller,
+				   struct bpf_func_state *callee,
+				   int insn_idx);
+
+static int set_callee_state(struct bpf_verifier_env *env,
+			    struct bpf_func_state *caller,
+			    struct bpf_func_state *callee, int insn_idx);
+
+static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+			     int *insn_idx, int subprog,
+			     set_callee_state_fn set_callee_state_cb)
+{
+	struct bpf_verifier_state *state = env->cur_state;
+	struct bpf_func_info_aux *func_info_aux;
+	struct bpf_func_state *caller, *callee;
+	int err;
+	bool is_global = false;
+
+	if (state->curframe + 1 >= MAX_CALL_FRAMES) {
+		verbose(env, "the call stack of %d frames is too deep\n",
+			state->curframe + 2);
+		return -E2BIG;
+	}
+
+	caller = state->frame[state->curframe];
+	if (state->frame[state->curframe + 1]) {
+		verbose(env, "verifier bug. Frame %d already allocated\n",
+			state->curframe + 1);
+		return -EFAULT;
+	}
+
+	func_info_aux = env->prog->aux->func_info_aux;
+	if (func_info_aux)
+		is_global = func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
+	err = btf_check_subprog_call(env, subprog, caller->regs);
+	if (err == -EFAULT)
+		return err;
+	if (is_global) {
+		if (err) {
+			verbose(env, "Caller passes invalid args into func#%d\n",
+				subprog);
+			return err;
+		} else {
+			if (env->log.level & BPF_LOG_LEVEL)
+				verbose(env,
+					"Func#%d is global and valid. Skipping.\n",
+					subprog);
+			clear_caller_saved_regs(env, caller->regs);
+
+			/* All global functions return a 64-bit SCALAR_VALUE */
+			mark_reg_unknown(env, caller->regs, BPF_REG_0);
+			caller->regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
+
+			/* continue with next insn after call */
+			return 0;
+		}
+	}
+
+	/* set_callee_state is used for direct subprog calls, but we are
+	 * interested in validating only BPF helpers that can call subprogs as
+	 * callbacks
+	 */
+	if (set_callee_state_cb != set_callee_state && !is_callback_calling_function(insn->imm)) {
+		verbose(env, "verifier bug: helper %s#%d is not marked as callback-calling\n",
+			func_id_name(insn->imm), insn->imm);
+		return -EFAULT;
+	}
+
+	if (insn->code == (BPF_JMP | BPF_CALL) &&
+	    insn->src_reg == 0 &&
+	    insn->imm == BPF_FUNC_timer_set_callback) {
+		struct bpf_verifier_state *async_cb;
+
+		/* there is no real recursion here. timer callbacks are async */
+		env->subprog_info[subprog].is_async_cb = true;
+		async_cb = push_async_cb(env, env->subprog_info[subprog].start,
+					 *insn_idx, subprog);
+		if (!async_cb)
+			return -EFAULT;
+		callee = async_cb->frame[0];
+		callee->async_entry_cnt = caller->async_entry_cnt + 1;
+
+		/* Convert bpf_timer_set_callback() args into timer callback args */
+		err = set_callee_state_cb(env, caller, callee, *insn_idx);
+		if (err)
+			return err;
+
+		clear_caller_saved_regs(env, caller->regs);
+		mark_reg_unknown(env, caller->regs, BPF_REG_0);
+		caller->regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
+		/* continue with next insn after call */
+		return 0;
+	}
+
+	callee = kzalloc(sizeof(*callee), GFP_KERNEL);
+	if (!callee)
+		return -ENOMEM;
+	state->frame[state->curframe + 1] = callee;
+
+	/* callee cannot access r0, r6 - r9 for reading and has to write
+	 * into its own stack before reading from it.
+	 * callee can read/write into caller's stack
+	 */
+	init_func_state(env, callee,
+			/* remember the callsite, it will be used by bpf_exit */
+			*insn_idx /* callsite */,
+			state->curframe + 1 /* frameno within this callchain */,
+			subprog /* subprog number within this prog */);
+
+	/* Transfer references to the callee */
+	err = copy_reference_state(callee, caller);
+	if (err)
+		goto err_out;
+
+	err = set_callee_state_cb(env, caller, callee, *insn_idx);
+	if (err)
+		goto err_out;
+
+	clear_caller_saved_regs(env, caller->regs);
+
+	/* only increment it after check_reg_arg() finished */
+	state->curframe++;
+
+	/* and go analyze first insn of the callee */
+	*insn_idx = env->subprog_info[subprog].start - 1;
+
+	if (env->log.level & BPF_LOG_LEVEL) {
+		verbose(env, "caller:\n");
+		print_verifier_state(env, caller, true);
+		verbose(env, "callee:\n");
+		print_verifier_state(env, callee, true);
+	}
+	return 0;
+
+err_out:
+	free_func_state(callee);
+	state->frame[state->curframe + 1] = NULL;
+	return err;
+}
+
+int map_set_for_each_callback_args(struct bpf_verifier_env *env,
+				   struct bpf_func_state *caller,
+				   struct bpf_func_state *callee)
+{
+	/* bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn,
+	 *      void *callback_ctx, u64 flags);
+	 * callback_fn(struct bpf_map *map, void *key, void *value,
+	 *      void *callback_ctx);
+	 */
+	callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1];
+
+	callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_2]);
+	callee->regs[BPF_REG_2].map_ptr = caller->regs[BPF_REG_1].map_ptr;
+
+	callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_3]);
+	callee->regs[BPF_REG_3].map_ptr = caller->regs[BPF_REG_1].map_ptr;
+
+	/* pointer to stack or null */
+	callee->regs[BPF_REG_4] = caller->regs[BPF_REG_3];
+
+	/* unused */
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+	return 0;
+}
+
+static int set_callee_state(struct bpf_verifier_env *env,
+			    struct bpf_func_state *caller,
+			    struct bpf_func_state *callee, int insn_idx)
+{
+	int i;
+
+	/* copy r1 - r5 args that callee can access.  The copy includes parent
+	 * pointers, which connects us up to the liveness chain
+	 */
+	for (i = BPF_REG_1; i <= BPF_REG_5; i++)
+		callee->regs[i] = caller->regs[i];
+	return 0;
+}
+
+static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+			   int *insn_idx)
+{
+	int subprog, target_insn;
+
+	target_insn = *insn_idx + insn->imm + 1;
+	subprog = find_subprog(env, target_insn);
+	if (subprog < 0) {
+		verbose(env, "verifier bug. No program starts at insn %d\n",
+			target_insn);
+		return -EFAULT;
+	}
+
+	return __check_func_call(env, insn, insn_idx, subprog, set_callee_state);
+}
+
+static int set_map_elem_callback_state(struct bpf_verifier_env *env,
+				       struct bpf_func_state *caller,
+				       struct bpf_func_state *callee,
+				       int insn_idx)
+{
+	struct bpf_insn_aux_data *insn_aux = &env->insn_aux_data[insn_idx];
+	struct bpf_map *map;
+	int err;
+
+	if (bpf_map_ptr_poisoned(insn_aux)) {
+		verbose(env, "tail_call abusing map_ptr\n");
+		return -EINVAL;
+	}
+
+	map = BPF_MAP_PTR(insn_aux->map_ptr_state);
+	if (!map->ops->map_set_for_each_callback_args ||
+	    !map->ops->map_for_each_callback) {
+		verbose(env, "callback function not allowed for map\n");
+		return -ENOTSUPP;
+	}
+
+	err = map->ops->map_set_for_each_callback_args(env, caller, callee);
+	if (err)
+		return err;
+
+	callee->in_callback_fn = true;
+	callee->callback_ret_range = tnum_range(0, 1);
+	return 0;
+}
+
+static int set_loop_callback_state(struct bpf_verifier_env *env,
+				   struct bpf_func_state *caller,
+				   struct bpf_func_state *callee,
+				   int insn_idx)
+{
+	/* bpf_loop(u32 nr_loops, void *callback_fn, void *callback_ctx,
+	 *	    u64 flags);
+	 * callback_fn(u32 index, void *callback_ctx);
+	 */
+	callee->regs[BPF_REG_1].type = SCALAR_VALUE;
+	callee->regs[BPF_REG_2] = caller->regs[BPF_REG_3];
+
+	/* unused */
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+
+	callee->in_callback_fn = true;
+	callee->callback_ret_range = tnum_range(0, 1);
+	return 0;
+}
+
+static int set_timer_callback_state(struct bpf_verifier_env *env,
+				    struct bpf_func_state *caller,
+				    struct bpf_func_state *callee,
+				    int insn_idx)
+{
+	struct bpf_map *map_ptr = caller->regs[BPF_REG_1].map_ptr;
+
+	/* bpf_timer_set_callback(struct bpf_timer *timer, void *callback_fn);
+	 * callback_fn(struct bpf_map *map, void *key, void *value);
+	 */
+	callee->regs[BPF_REG_1].type = CONST_PTR_TO_MAP;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_1]);
+	callee->regs[BPF_REG_1].map_ptr = map_ptr;
+
+	callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_2]);
+	callee->regs[BPF_REG_2].map_ptr = map_ptr;
+
+	callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_3]);
+	callee->regs[BPF_REG_3].map_ptr = map_ptr;
+
+	/* unused */
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+	callee->in_async_callback_fn = true;
+	callee->callback_ret_range = tnum_range(0, 1);
+	return 0;
+}
+
+static int set_find_vma_callback_state(struct bpf_verifier_env *env,
+				       struct bpf_func_state *caller,
+				       struct bpf_func_state *callee,
+				       int insn_idx)
+{
+	/* bpf_find_vma(struct task_struct *task, u64 addr,
+	 *               void *callback_fn, void *callback_ctx, u64 flags)
+	 * (callback_fn)(struct task_struct *task,
+	 *               struct vm_area_struct *vma, void *callback_ctx);
+	 */
+	callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1];
+
+	callee->regs[BPF_REG_2].type = PTR_TO_BTF_ID;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_2]);
+	callee->regs[BPF_REG_2].btf =  btf_vmlinux;
+	callee->regs[BPF_REG_2].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_VMA],
+
+	/* pointer to stack or null */
+	callee->regs[BPF_REG_3] = caller->regs[BPF_REG_4];
+
+	/* unused */
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+	callee->in_callback_fn = true;
+	callee->callback_ret_range = tnum_range(0, 1);
+	return 0;
+}
+
+static int set_user_ringbuf_callback_state(struct bpf_verifier_env *env,
+					   struct bpf_func_state *caller,
+					   struct bpf_func_state *callee,
+					   int insn_idx)
+{
+	/* bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void
+	 *			  callback_ctx, u64 flags);
+	 * callback_fn(struct bpf_dynptr_t* dynptr, void *callback_ctx);
+	 */
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_0]);
+	callee->regs[BPF_REG_1].type = PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_1]);
+	callee->regs[BPF_REG_2] = caller->regs[BPF_REG_3];
+
+	/* unused */
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+
+	callee->in_callback_fn = true;
+	callee->callback_ret_range = tnum_range(0, 1);
+	return 0;
+}
+
+static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
+{
+	struct bpf_verifier_state *state = env->cur_state;
+	struct bpf_func_state *caller, *callee;
+	struct bpf_reg_state *r0;
+	int err;
+
+	callee = state->frame[state->curframe];
+	r0 = &callee->regs[BPF_REG_0];
+	if (r0->type == PTR_TO_STACK) {
+		/* technically it's ok to return caller's stack pointer
+		 * (or caller's caller's pointer) back to the caller,
+		 * since these pointers are valid. Only current stack
+		 * pointer will be invalid as soon as function exits,
+		 * but let's be conservative
+		 */
+		verbose(env, "cannot return stack pointer to the caller\n");
+		return -EINVAL;
+	}
+
+	caller = state->frame[state->curframe - 1];
+	if (callee->in_callback_fn) {
+		/* enforce R0 return value range [0, 1]. */
+		struct tnum range = callee->callback_ret_range;
+
+		if (r0->type != SCALAR_VALUE) {
+			verbose(env, "R0 not a scalar value\n");
+			return -EACCES;
+		}
+
+		/* we are going to rely on register's precise value */
+		err = mark_reg_read(env, r0, r0->parent, REG_LIVE_READ64);
+		err = err ?: mark_chain_precision(env, BPF_REG_0);
+		if (err)
+			return err;
+
+		if (!tnum_in(range, r0->var_off)) {
+			verbose_invalid_scalar(env, r0, &range, "callback return", "R0");
+			return -EINVAL;
+		}
+	} else {
+		/* return to the caller whatever r0 had in the callee */
+		caller->regs[BPF_REG_0] = *r0;
+	}
+
+	/* callback_fn frame should have released its own additions to parent's
+	 * reference state at this point, or check_reference_leak would
+	 * complain, hence it must be the same as the caller. There is no need
+	 * to copy it back.
+	 */
+	if (!callee->in_callback_fn) {
+		/* Transfer references to the caller */
+		err = copy_reference_state(caller, callee);
+		if (err)
+			return err;
+	}
+
+	*insn_idx = callee->callsite + 1;
+	if (env->log.level & BPF_LOG_LEVEL) {
+		verbose(env, "returning from callee:\n");
+		print_verifier_state(env, callee, true);
+		verbose(env, "to caller at %d:\n", *insn_idx);
+		print_verifier_state(env, caller, true);
+	}
+	/* clear everything in the callee */
+	free_func_state(callee);
+	state->frame[state->curframe--] = NULL;
+	return 0;
+}
+
+static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
+				   int func_id,
+				   struct bpf_call_arg_meta *meta)
+{
+	struct bpf_reg_state *ret_reg = &regs[BPF_REG_0];
+
+	if (ret_type != RET_INTEGER ||
+	    (func_id != BPF_FUNC_get_stack &&
+	     func_id != BPF_FUNC_get_task_stack &&
+	     func_id != BPF_FUNC_probe_read_str &&
+	     func_id != BPF_FUNC_probe_read_kernel_str &&
+	     func_id != BPF_FUNC_probe_read_user_str))
+		return;
+
+	ret_reg->smax_value = meta->msize_max_value;
+	ret_reg->s32_max_value = meta->msize_max_value;
+	ret_reg->smin_value = -MAX_ERRNO;
+	ret_reg->s32_min_value = -MAX_ERRNO;
+	reg_bounds_sync(ret_reg);
+}
+
+static int
+record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
+		int func_id, int insn_idx)
+{
+	struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
+	struct bpf_map *map = meta->map_ptr;
+
+	if (func_id != BPF_FUNC_tail_call &&
+	    func_id != BPF_FUNC_map_lookup_elem &&
+	    func_id != BPF_FUNC_map_update_elem &&
+	    func_id != BPF_FUNC_map_delete_elem &&
+	    func_id != BPF_FUNC_map_push_elem &&
+	    func_id != BPF_FUNC_map_pop_elem &&
+	    func_id != BPF_FUNC_map_peek_elem &&
+	    func_id != BPF_FUNC_for_each_map_elem &&
+	    func_id != BPF_FUNC_redirect_map &&
+	    func_id != BPF_FUNC_map_lookup_percpu_elem)
+		return 0;
+
+	if (map == NULL) {
+		verbose(env, "kernel subsystem misconfigured verifier\n");
+		return -EINVAL;
+	}
+
+	/* In case of read-only, some additional restrictions
+	 * need to be applied in order to prevent altering the
+	 * state of the map from program side.
+	 */
+	if ((map->map_flags & BPF_F_RDONLY_PROG) &&
+	    (func_id == BPF_FUNC_map_delete_elem ||
+	     func_id == BPF_FUNC_map_update_elem ||
+	     func_id == BPF_FUNC_map_push_elem ||
+	     func_id == BPF_FUNC_map_pop_elem)) {
+		verbose(env, "write into map forbidden\n");
+		return -EACCES;
+	}
+
+	if (!BPF_MAP_PTR(aux->map_ptr_state))
+		bpf_map_ptr_store(aux, meta->map_ptr,
+				  !meta->map_ptr->bypass_spec_v1);
+	else if (BPF_MAP_PTR(aux->map_ptr_state) != meta->map_ptr)
+		bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON,
+				  !meta->map_ptr->bypass_spec_v1);
+	return 0;
+}
+
+static int
+record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
+		int func_id, int insn_idx)
+{
+	struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
+	struct bpf_reg_state *regs = cur_regs(env), *reg;
+	struct bpf_map *map = meta->map_ptr;
+	u64 val, max;
+	int err;
+
+	if (func_id != BPF_FUNC_tail_call)
+		return 0;
+	if (!map || map->map_type != BPF_MAP_TYPE_PROG_ARRAY) {
+		verbose(env, "kernel subsystem misconfigured verifier\n");
+		return -EINVAL;
+	}
+
+	reg = &regs[BPF_REG_3];
+	val = reg->var_off.value;
+	max = map->max_entries;
+
+	if (!(register_is_const(reg) && val < max)) {
+		bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
+		return 0;
+	}
+
+	err = mark_chain_precision(env, BPF_REG_3);
+	if (err)
+		return err;
+	if (bpf_map_key_unseen(aux))
+		bpf_map_key_store(aux, val);
+	else if (!bpf_map_key_poisoned(aux) &&
+		  bpf_map_key_immediate(aux) != val)
+		bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
+	return 0;
+}
+
+static int check_reference_leak(struct bpf_verifier_env *env)
+{
+	struct bpf_func_state *state = cur_func(env);
+	bool refs_lingering = false;
+	int i;
+
+	if (state->frameno && !state->in_callback_fn)
+		return 0;
+
+	for (i = 0; i < state->acquired_refs; i++) {
+		if (state->in_callback_fn && state->refs[i].callback_ref != state->frameno)
+			continue;
+		verbose(env, "Unreleased reference id=%d alloc_insn=%d\n",
+			state->refs[i].id, state->refs[i].insn_idx);
+		refs_lingering = true;
+	}
+	return refs_lingering ? -EINVAL : 0;
+}
+
+static int check_bpf_snprintf_call(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *regs)
+{
+	struct bpf_reg_state *fmt_reg = &regs[BPF_REG_3];
+	struct bpf_reg_state *data_len_reg = &regs[BPF_REG_5];
+	struct bpf_map *fmt_map = fmt_reg->map_ptr;
+	int err, fmt_map_off, num_args;
+	u64 fmt_addr;
+	char *fmt;
+
+	/* data must be an array of u64 */
+	if (data_len_reg->var_off.value % 8)
+		return -EINVAL;
+	num_args = data_len_reg->var_off.value / 8;
+
+	/* fmt being ARG_PTR_TO_CONST_STR guarantees that var_off is const
+	 * and map_direct_value_addr is set.
+	 */
+	fmt_map_off = fmt_reg->off + fmt_reg->var_off.value;
+	err = fmt_map->ops->map_direct_value_addr(fmt_map, &fmt_addr,
+						  fmt_map_off);
+	if (err) {
+		verbose(env, "verifier bug\n");
+		return -EFAULT;
+	}
+	fmt = (char *)(long)fmt_addr + fmt_map_off;
+
+	/* We are also guaranteed that fmt+fmt_map_off is NULL terminated, we
+	 * can focus on validating the format specifiers.
+	 */
+	err = bpf_bprintf_prepare(fmt, UINT_MAX, NULL, NULL, num_args);
+	if (err < 0)
+		verbose(env, "Invalid format string\n");
+
+	return err;
+}
+
+static int check_get_func_ip(struct bpf_verifier_env *env)
+{
+	enum bpf_prog_type type = resolve_prog_type(env->prog);
+	int func_id = BPF_FUNC_get_func_ip;
+
+	if (type == BPF_PROG_TYPE_TRACING) {
+		if (!bpf_prog_has_trampoline(env->prog)) {
+			verbose(env, "func %s#%d supported only for fentry/fexit/fmod_ret programs\n",
+				func_id_name(func_id), func_id);
+			return -ENOTSUPP;
+		}
+		return 0;
+	} else if (type == BPF_PROG_TYPE_KPROBE) {
+		return 0;
+	}
+
+	verbose(env, "func %s#%d not supported for program type %d\n",
+		func_id_name(func_id), func_id, type);
+	return -ENOTSUPP;
+}
+
+static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env)
+{
+	return &env->insn_aux_data[env->insn_idx];
+}
+
+static bool loop_flag_is_zero(struct bpf_verifier_env *env)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *reg = &regs[BPF_REG_4];
+	bool reg_is_null = register_is_null(reg);
+
+	if (reg_is_null)
+		mark_chain_precision(env, BPF_REG_4);
+
+	return reg_is_null;
+}
+
+static void update_loop_inline_state(struct bpf_verifier_env *env, u32 subprogno)
+{
+	struct bpf_loop_inline_state *state = &cur_aux(env)->loop_inline_state;
+
+	if (!state->initialized) {
+		state->initialized = 1;
+		state->fit_for_inline = loop_flag_is_zero(env);
+		state->callback_subprogno = subprogno;
+		return;
+	}
+
+	if (!state->fit_for_inline)
+		return;
+
+	state->fit_for_inline = (loop_flag_is_zero(env) &&
+				 state->callback_subprogno == subprogno);
+}
+
+static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+			     int *insn_idx_p)
+{
+	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
+	const struct bpf_func_proto *fn = NULL;
+	enum bpf_return_type ret_type;
+	enum bpf_type_flag ret_flag;
+	struct bpf_reg_state *regs;
+	struct bpf_call_arg_meta meta;
+	int insn_idx = *insn_idx_p;
+	bool changes_data;
+	int i, err, func_id;
+
+	/* find function prototype */
+	func_id = insn->imm;
+	if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) {
+		verbose(env, "invalid func %s#%d\n", func_id_name(func_id),
+			func_id);
+		return -EINVAL;
+	}
+
+	if (env->ops->get_func_proto)
+		fn = env->ops->get_func_proto(func_id, env->prog);
+	if (!fn) {
+		verbose(env, "unknown func %s#%d\n", func_id_name(func_id),
+			func_id);
+		return -EINVAL;
+	}
+
+	/* eBPF programs must be GPL compatible to use GPL-ed functions */
+	if (!env->prog->gpl_compatible && fn->gpl_only) {
+		verbose(env, "cannot call GPL-restricted function from non-GPL compatible program\n");
+		return -EINVAL;
+	}
+
+	if (fn->allowed && !fn->allowed(env->prog)) {
+		verbose(env, "helper call is not allowed in probe\n");
+		return -EINVAL;
+	}
+
+	/* With LD_ABS/IND some JITs save/restore skb from r1. */
+	changes_data = bpf_helper_changes_pkt_data(fn->func);
+	if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) {
+		verbose(env, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n",
+			func_id_name(func_id), func_id);
+		return -EINVAL;
+	}
+
+	memset(&meta, 0, sizeof(meta));
+	meta.pkt_access = fn->pkt_access;
+
+	err = check_func_proto(fn, func_id);
+	if (err) {
+		verbose(env, "kernel subsystem misconfigured func %s#%d\n",
+			func_id_name(func_id), func_id);
+		return err;
+	}
+
+	meta.func_id = func_id;
+	/* check args */
+	for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
+		err = check_func_arg(env, i, &meta, fn);
+		if (err)
+			return err;
+	}
+
+	err = record_func_map(env, &meta, func_id, insn_idx);
+	if (err)
+		return err;
+
+	err = record_func_key(env, &meta, func_id, insn_idx);
+	if (err)
+		return err;
+
+	/* Mark slots with STACK_MISC in case of raw mode, stack offset
+	 * is inferred from register state.
+	 */
+	for (i = 0; i < meta.access_size; i++) {
+		err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
+				       BPF_WRITE, -1, false);
+		if (err)
+			return err;
+	}
+
+	regs = cur_regs(env);
+
+	if (meta.uninit_dynptr_regno) {
+		/* we write BPF_DW bits (8 bytes) at a time */
+		for (i = 0; i < BPF_DYNPTR_SIZE; i += 8) {
+			err = check_mem_access(env, insn_idx, meta.uninit_dynptr_regno,
+					       i, BPF_DW, BPF_WRITE, -1, false);
+			if (err)
+				return err;
+		}
+
+		err = mark_stack_slots_dynptr(env, &regs[meta.uninit_dynptr_regno],
+					      fn->arg_type[meta.uninit_dynptr_regno - BPF_REG_1],
+					      insn_idx);
+		if (err)
+			return err;
+	}
+
+	if (meta.release_regno) {
+		err = -EINVAL;
+		if (arg_type_is_dynptr(fn->arg_type[meta.release_regno - BPF_REG_1]))
+			err = unmark_stack_slots_dynptr(env, &regs[meta.release_regno]);
+		else if (meta.ref_obj_id)
+			err = release_reference(env, meta.ref_obj_id);
+		/* meta.ref_obj_id can only be 0 if register that is meant to be
+		 * released is NULL, which must be > R0.
+		 */
+		else if (register_is_null(&regs[meta.release_regno]))
+			err = 0;
+		if (err) {
+			verbose(env, "func %s#%d reference has not been acquired before\n",
+				func_id_name(func_id), func_id);
+			return err;
+		}
+	}
+
+	switch (func_id) {
+	case BPF_FUNC_tail_call:
+		err = check_reference_leak(env);
+		if (err) {
+			verbose(env, "tail_call would lead to reference leak\n");
+			return err;
+		}
+		break;
+	case BPF_FUNC_get_local_storage:
+		/* check that flags argument in get_local_storage(map, flags) is 0,
+		 * this is required because get_local_storage() can't return an error.
+		 */
+		if (!register_is_null(&regs[BPF_REG_2])) {
+			verbose(env, "get_local_storage() doesn't support non-zero flags\n");
+			return -EINVAL;
+		}
+		break;
+	case BPF_FUNC_for_each_map_elem:
+		err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
+					set_map_elem_callback_state);
+		break;
+	case BPF_FUNC_timer_set_callback:
+		err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
+					set_timer_callback_state);
+		break;
+	case BPF_FUNC_find_vma:
+		err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
+					set_find_vma_callback_state);
+		break;
+	case BPF_FUNC_snprintf:
+		err = check_bpf_snprintf_call(env, regs);
+		break;
+	case BPF_FUNC_loop:
+		update_loop_inline_state(env, meta.subprogno);
+		err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
+					set_loop_callback_state);
+		break;
+	case BPF_FUNC_dynptr_from_mem:
+		if (regs[BPF_REG_1].type != PTR_TO_MAP_VALUE) {
+			verbose(env, "Unsupported reg type %s for bpf_dynptr_from_mem data\n",
+				reg_type_str(env, regs[BPF_REG_1].type));
+			return -EACCES;
+		}
+		break;
+	case BPF_FUNC_set_retval:
+		if (prog_type == BPF_PROG_TYPE_LSM &&
+		    env->prog->expected_attach_type == BPF_LSM_CGROUP) {
+			if (!env->prog->aux->attach_func_proto->type) {
+				/* Make sure programs that attach to void
+				 * hooks don't try to modify return value.
+				 */
+				verbose(env, "BPF_LSM_CGROUP that attach to void LSM hooks can't modify return value!\n");
+				return -EINVAL;
+			}
+		}
+		break;
+	case BPF_FUNC_dynptr_data:
+		for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
+			if (arg_type_is_dynptr(fn->arg_type[i])) {
+				struct bpf_reg_state *reg = &regs[BPF_REG_1 + i];
+
+				if (meta.ref_obj_id) {
+					verbose(env, "verifier internal error: meta.ref_obj_id already set\n");
+					return -EFAULT;
+				}
+
+				if (base_type(reg->type) != PTR_TO_DYNPTR)
+					/* Find the id of the dynptr we're
+					 * tracking the reference of
+					 */
+					meta.ref_obj_id = stack_slot_get_id(env, reg);
+				break;
+			}
+		}
+		if (i == MAX_BPF_FUNC_REG_ARGS) {
+			verbose(env, "verifier internal error: no dynptr in bpf_dynptr_data()\n");
+			return -EFAULT;
+		}
+		break;
+	case BPF_FUNC_user_ringbuf_drain:
+		err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
+					set_user_ringbuf_callback_state);
+		break;
+	}
+
+	if (err)
+		return err;
+
+	/* reset caller saved regs */
+	for (i = 0; i < CALLER_SAVED_REGS; i++) {
+		mark_reg_not_init(env, regs, caller_saved[i]);
+		check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+	}
+
+	/* helper call returns 64-bit value. */
+	regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
+
+	/* update return register (already marked as written above) */
+	ret_type = fn->ret_type;
+	ret_flag = type_flag(ret_type);
+
+	switch (base_type(ret_type)) {
+	case RET_INTEGER:
+		/* sets type to SCALAR_VALUE */
+		mark_reg_unknown(env, regs, BPF_REG_0);
+		break;
+	case RET_VOID:
+		regs[BPF_REG_0].type = NOT_INIT;
+		break;
+	case RET_PTR_TO_MAP_VALUE:
+		/* There is no offset yet applied, variable or fixed */
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		/* remember map_ptr, so that check_map_access()
+		 * can check 'value_size' boundary of memory access
+		 * to map element returned from bpf_map_lookup_elem()
+		 */
+		if (meta.map_ptr == NULL) {
+			verbose(env,
+				"kernel subsystem misconfigured verifier\n");
+			return -EINVAL;
+		}
+		regs[BPF_REG_0].map_ptr = meta.map_ptr;
+		regs[BPF_REG_0].map_uid = meta.map_uid;
+		regs[BPF_REG_0].type = PTR_TO_MAP_VALUE | ret_flag;
+		if (!type_may_be_null(ret_type) &&
+		    map_value_has_spin_lock(meta.map_ptr)) {
+			regs[BPF_REG_0].id = ++env->id_gen;
+		}
+		break;
+	case RET_PTR_TO_SOCKET:
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		regs[BPF_REG_0].type = PTR_TO_SOCKET | ret_flag;
+		break;
+	case RET_PTR_TO_SOCK_COMMON:
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON | ret_flag;
+		break;
+	case RET_PTR_TO_TCP_SOCK:
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag;
+		break;
+	case RET_PTR_TO_ALLOC_MEM:
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
+		regs[BPF_REG_0].mem_size = meta.mem_size;
+		break;
+	case RET_PTR_TO_MEM_OR_BTF_ID:
+	{
+		const struct btf_type *t;
+
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		t = btf_type_skip_modifiers(meta.ret_btf, meta.ret_btf_id, NULL);
+		if (!btf_type_is_struct(t)) {
+			u32 tsize;
+			const struct btf_type *ret;
+			const char *tname;
+
+			/* resolve the type size of ksym. */
+			ret = btf_resolve_size(meta.ret_btf, t, &tsize);
+			if (IS_ERR(ret)) {
+				tname = btf_name_by_offset(meta.ret_btf, t->name_off);
+				verbose(env, "unable to resolve the size of type '%s': %ld\n",
+					tname, PTR_ERR(ret));
+				return -EINVAL;
+			}
+			regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
+			regs[BPF_REG_0].mem_size = tsize;
+		} else {
+			/* MEM_RDONLY may be carried from ret_flag, but it
+			 * doesn't apply on PTR_TO_BTF_ID. Fold it, otherwise
+			 * it will confuse the check of PTR_TO_BTF_ID in
+			 * check_mem_access().
+			 */
+			ret_flag &= ~MEM_RDONLY;
+
+			regs[BPF_REG_0].type = PTR_TO_BTF_ID | ret_flag;
+			regs[BPF_REG_0].btf = meta.ret_btf;
+			regs[BPF_REG_0].btf_id = meta.ret_btf_id;
+		}
+		break;
+	}
+	case RET_PTR_TO_BTF_ID:
+	{
+		struct btf *ret_btf;
+		int ret_btf_id;
+
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		regs[BPF_REG_0].type = PTR_TO_BTF_ID | ret_flag;
+		if (func_id == BPF_FUNC_kptr_xchg) {
+			ret_btf = meta.kptr_off_desc->kptr.btf;
+			ret_btf_id = meta.kptr_off_desc->kptr.btf_id;
+		} else {
+			if (fn->ret_btf_id == BPF_PTR_POISON) {
+				verbose(env, "verifier internal error:");
+				verbose(env, "func %s has non-overwritten BPF_PTR_POISON return type\n",
+					func_id_name(func_id));
+				return -EINVAL;
+			}
+			ret_btf = btf_vmlinux;
+			ret_btf_id = *fn->ret_btf_id;
+		}
+		if (ret_btf_id == 0) {
+			verbose(env, "invalid return type %u of func %s#%d\n",
+				base_type(ret_type), func_id_name(func_id),
+				func_id);
+			return -EINVAL;
+		}
+		regs[BPF_REG_0].btf = ret_btf;
+		regs[BPF_REG_0].btf_id = ret_btf_id;
+		break;
+	}
+	default:
+		verbose(env, "unknown return type %u of func %s#%d\n",
+			base_type(ret_type), func_id_name(func_id), func_id);
+		return -EINVAL;
+	}
+
+	if (type_may_be_null(regs[BPF_REG_0].type))
+		regs[BPF_REG_0].id = ++env->id_gen;
+
+	if (helper_multiple_ref_obj_use(func_id, meta.map_ptr)) {
+		verbose(env, "verifier internal error: func %s#%d sets ref_obj_id more than once\n",
+			func_id_name(func_id), func_id);
+		return -EFAULT;
+	}
+
+	if (is_ptr_cast_function(func_id) || is_dynptr_ref_function(func_id)) {
+		/* For release_reference() */
+		regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
+	} else if (is_acquire_function(func_id, meta.map_ptr)) {
+		int id = acquire_reference_state(env, insn_idx);
+
+		if (id < 0)
+			return id;
+		/* For mark_ptr_or_null_reg() */
+		regs[BPF_REG_0].id = id;
+		/* For release_reference() */
+		regs[BPF_REG_0].ref_obj_id = id;
+	}
+
+	do_refine_retval_range(regs, fn->ret_type, func_id, &meta);
+
+	err = check_map_func_compatibility(env, meta.map_ptr, func_id);
+	if (err)
+		return err;
+
+	if ((func_id == BPF_FUNC_get_stack ||
+	     func_id == BPF_FUNC_get_task_stack) &&
+	    !env->prog->has_callchain_buf) {
+		const char *err_str;
+
+#ifdef CONFIG_PERF_EVENTS
+		err = get_callchain_buffers(sysctl_perf_event_max_stack);
+		err_str = "cannot get callchain buffer for func %s#%d\n";
+#else
+		err = -ENOTSUPP;
+		err_str = "func %s#%d not supported without CONFIG_PERF_EVENTS\n";
+#endif
+		if (err) {
+			verbose(env, err_str, func_id_name(func_id), func_id);
+			return err;
+		}
+
+		env->prog->has_callchain_buf = true;
+	}
+
+	if (func_id == BPF_FUNC_get_stackid || func_id == BPF_FUNC_get_stack)
+		env->prog->call_get_stack = true;
+
+	if (func_id == BPF_FUNC_get_func_ip) {
+		if (check_get_func_ip(env))
+			return -ENOTSUPP;
+		env->prog->call_get_func_ip = true;
+	}
+
+	if (changes_data)
+		clear_all_pkt_pointers(env);
+	return 0;
+}
+
+/* mark_btf_func_reg_size() is used when the reg size is determined by
+ * the BTF func_proto's return value size and argument.
+ */
+static void mark_btf_func_reg_size(struct bpf_verifier_env *env, u32 regno,
+				   size_t reg_size)
+{
+	struct bpf_reg_state *reg = &cur_regs(env)[regno];
+
+	if (regno == BPF_REG_0) {
+		/* Function return value */
+		reg->live |= REG_LIVE_WRITTEN;
+		reg->subreg_def = reg_size == sizeof(u64) ?
+			DEF_NOT_SUBREG : env->insn_idx + 1;
+	} else {
+		/* Function argument */
+		if (reg_size == sizeof(u64)) {
+			mark_insn_zext(env, reg);
+			mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+		} else {
+			mark_reg_read(env, reg, reg->parent, REG_LIVE_READ32);
+		}
+	}
+}
+
+static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+			    int *insn_idx_p)
+{
+	const struct btf_type *t, *func, *func_proto, *ptr_type;
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_kfunc_arg_meta meta = { 0 };
+	const char *func_name, *ptr_type_name;
+	u32 i, nargs, func_id, ptr_type_id;
+	int err, insn_idx = *insn_idx_p;
+	const struct btf_param *args;
+	struct btf *desc_btf;
+	u32 *kfunc_flags;
+	bool acq;
+
+	/* skip for now, but return error when we find this in fixup_kfunc_call */
+	if (!insn->imm)
+		return 0;
+
+	desc_btf = find_kfunc_desc_btf(env, insn->off);
+	if (IS_ERR(desc_btf))
+		return PTR_ERR(desc_btf);
+
+	func_id = insn->imm;
+	func = btf_type_by_id(desc_btf, func_id);
+	func_name = btf_name_by_offset(desc_btf, func->name_off);
+	func_proto = btf_type_by_id(desc_btf, func->type);
+
+	kfunc_flags = btf_kfunc_id_set_contains(desc_btf, resolve_prog_type(env->prog), func_id);
+	if (!kfunc_flags) {
+		verbose(env, "calling kernel function %s is not allowed\n",
+			func_name);
+		return -EACCES;
+	}
+	if (*kfunc_flags & KF_DESTRUCTIVE && !capable(CAP_SYS_BOOT)) {
+		verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capabilities\n");
+		return -EACCES;
+	}
+
+	acq = *kfunc_flags & KF_ACQUIRE;
+
+	meta.flags = *kfunc_flags;
+
+	/* Check the arguments */
+	err = btf_check_kfunc_arg_match(env, desc_btf, func_id, regs, &meta);
+	if (err < 0)
+		return err;
+	/* In case of release function, we get register number of refcounted
+	 * PTR_TO_BTF_ID back from btf_check_kfunc_arg_match, do the release now
+	 */
+	if (err) {
+		err = release_reference(env, regs[err].ref_obj_id);
+		if (err) {
+			verbose(env, "kfunc %s#%d reference has not been acquired before\n",
+				func_name, func_id);
+			return err;
+		}
+	}
+
+	for (i = 0; i < CALLER_SAVED_REGS; i++)
+		mark_reg_not_init(env, regs, caller_saved[i]);
+
+	/* Check return type */
+	t = btf_type_skip_modifiers(desc_btf, func_proto->type, NULL);
+
+	if (acq && !btf_type_is_struct_ptr(desc_btf, t)) {
+		verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n");
+		return -EINVAL;
+	}
+
+	if (btf_type_is_scalar(t)) {
+		mark_reg_unknown(env, regs, BPF_REG_0);
+		mark_btf_func_reg_size(env, BPF_REG_0, t->size);
+	} else if (btf_type_is_ptr(t)) {
+		ptr_type = btf_type_skip_modifiers(desc_btf, t->type,
+						   &ptr_type_id);
+		if (!btf_type_is_struct(ptr_type)) {
+			if (!meta.r0_size) {
+				ptr_type_name = btf_name_by_offset(desc_btf,
+								   ptr_type->name_off);
+				verbose(env,
+					"kernel function %s returns pointer type %s %s is not supported\n",
+					func_name,
+					btf_type_str(ptr_type),
+					ptr_type_name);
+				return -EINVAL;
+			}
+
+			mark_reg_known_zero(env, regs, BPF_REG_0);
+			regs[BPF_REG_0].type = PTR_TO_MEM;
+			regs[BPF_REG_0].mem_size = meta.r0_size;
+
+			if (meta.r0_rdonly)
+				regs[BPF_REG_0].type |= MEM_RDONLY;
+
+			/* Ensures we don't access the memory after a release_reference() */
+			if (meta.ref_obj_id)
+				regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
+		} else {
+			mark_reg_known_zero(env, regs, BPF_REG_0);
+			regs[BPF_REG_0].btf = desc_btf;
+			regs[BPF_REG_0].type = PTR_TO_BTF_ID;
+			regs[BPF_REG_0].btf_id = ptr_type_id;
+		}
+		if (*kfunc_flags & KF_RET_NULL) {
+			regs[BPF_REG_0].type |= PTR_MAYBE_NULL;
+			/* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */
+			regs[BPF_REG_0].id = ++env->id_gen;
+		}
+		mark_btf_func_reg_size(env, BPF_REG_0, sizeof(void *));
+		if (acq) {
+			int id = acquire_reference_state(env, insn_idx);
+
+			if (id < 0)
+				return id;
+			regs[BPF_REG_0].id = id;
+			regs[BPF_REG_0].ref_obj_id = id;
+		}
+	} /* else { add_kfunc_call() ensures it is btf_type_is_void(t) } */
+
+	nargs = btf_type_vlen(func_proto);
+	args = (const struct btf_param *)(func_proto + 1);
+	for (i = 0; i < nargs; i++) {
+		u32 regno = i + 1;
+
+		t = btf_type_skip_modifiers(desc_btf, args[i].type, NULL);
+		if (btf_type_is_ptr(t))
+			mark_btf_func_reg_size(env, regno, sizeof(void *));
+		else
+			/* scalar. ensured by btf_check_kfunc_arg_match() */
+			mark_btf_func_reg_size(env, regno, t->size);
+	}
+
+	return 0;
+}
+
+static bool signed_add_overflows(s64 a, s64 b)
+{
+	/* Do the add in u64, where overflow is well-defined */
+	s64 res = (s64)((u64)a + (u64)b);
+
+	if (b < 0)
+		return res > a;
+	return res < a;
+}
+
+static bool signed_add32_overflows(s32 a, s32 b)
+{
+	/* Do the add in u32, where overflow is well-defined */
+	s32 res = (s32)((u32)a + (u32)b);
+
+	if (b < 0)
+		return res > a;
+	return res < a;
+}
+
+static bool signed_sub_overflows(s64 a, s64 b)
+{
+	/* Do the sub in u64, where overflow is well-defined */
+	s64 res = (s64)((u64)a - (u64)b);
+
+	if (b < 0)
+		return res < a;
+	return res > a;
+}
+
+static bool signed_sub32_overflows(s32 a, s32 b)
+{
+	/* Do the sub in u32, where overflow is well-defined */
+	s32 res = (s32)((u32)a - (u32)b);
+
+	if (b < 0)
+		return res < a;
+	return res > a;
+}
+
+static bool check_reg_sane_offset(struct bpf_verifier_env *env,
+				  const struct bpf_reg_state *reg,
+				  enum bpf_reg_type type)
+{
+	bool known = tnum_is_const(reg->var_off);
+	s64 val = reg->var_off.value;
+	s64 smin = reg->smin_value;
+
+	if (known && (val >= BPF_MAX_VAR_OFF || val <= -BPF_MAX_VAR_OFF)) {
+		verbose(env, "math between %s pointer and %lld is not allowed\n",
+			reg_type_str(env, type), val);
+		return false;
+	}
+
+	if (reg->off >= BPF_MAX_VAR_OFF || reg->off <= -BPF_MAX_VAR_OFF) {
+		verbose(env, "%s pointer offset %d is not allowed\n",
+			reg_type_str(env, type), reg->off);
+		return false;
+	}
+
+	if (smin == S64_MIN) {
+		verbose(env, "math between %s pointer and register with unbounded min value is not allowed\n",
+			reg_type_str(env, type));
+		return false;
+	}
+
+	if (smin >= BPF_MAX_VAR_OFF || smin <= -BPF_MAX_VAR_OFF) {
+		verbose(env, "value %lld makes %s pointer be out of bounds\n",
+			smin, reg_type_str(env, type));
+		return false;
+	}
+
+	return true;
+}
+
+enum {
+	REASON_BOUNDS	= -1,
+	REASON_TYPE	= -2,
+	REASON_PATHS	= -3,
+	REASON_LIMIT	= -4,
+	REASON_STACK	= -5,
+};
+
+static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg,
+			      u32 *alu_limit, bool mask_to_left)
+{
+	u32 max = 0, ptr_limit = 0;
+
+	switch (ptr_reg->type) {
+	case PTR_TO_STACK:
+		/* Offset 0 is out-of-bounds, but acceptable start for the
+		 * left direction, see BPF_REG_FP. Also, unknown scalar
+		 * offset where we would need to deal with min/max bounds is
+		 * currently prohibited for unprivileged.
+		 */
+		max = MAX_BPF_STACK + mask_to_left;
+		ptr_limit = -(ptr_reg->var_off.value + ptr_reg->off);
+		break;
+	case PTR_TO_MAP_VALUE:
+		max = ptr_reg->map_ptr->value_size;
+		ptr_limit = (mask_to_left ?
+			     ptr_reg->smin_value :
+			     ptr_reg->umax_value) + ptr_reg->off;
+		break;
+	default:
+		return REASON_TYPE;
+	}
+
+	if (ptr_limit >= max)
+		return REASON_LIMIT;
+	*alu_limit = ptr_limit;
+	return 0;
+}
+
+static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env,
+				    const struct bpf_insn *insn)
+{
+	return env->bypass_spec_v1 || BPF_SRC(insn->code) == BPF_K;
+}
+
+static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux,
+				       u32 alu_state, u32 alu_limit)
+{
+	/* If we arrived here from different branches with different
+	 * state or limits to sanitize, then this won't work.
+	 */
+	if (aux->alu_state &&
+	    (aux->alu_state != alu_state ||
+	     aux->alu_limit != alu_limit))
+		return REASON_PATHS;
+
+	/* Corresponding fixup done in do_misc_fixups(). */
+	aux->alu_state = alu_state;
+	aux->alu_limit = alu_limit;
+	return 0;
+}
+
+static int sanitize_val_alu(struct bpf_verifier_env *env,
+			    struct bpf_insn *insn)
+{
+	struct bpf_insn_aux_data *aux = cur_aux(env);
+
+	if (can_skip_alu_sanitation(env, insn))
+		return 0;
+
+	return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0);
+}
+
+static bool sanitize_needed(u8 opcode)
+{
+	return opcode == BPF_ADD || opcode == BPF_SUB;
+}
+
+struct bpf_sanitize_info {
+	struct bpf_insn_aux_data aux;
+	bool mask_to_left;
+};
+
+static struct bpf_verifier_state *
+sanitize_speculative_path(struct bpf_verifier_env *env,
+			  const struct bpf_insn *insn,
+			  u32 next_idx, u32 curr_idx)
+{
+	struct bpf_verifier_state *branch;
+	struct bpf_reg_state *regs;
+
+	branch = push_stack(env, next_idx, curr_idx, true);
+	if (branch && insn) {
+		regs = branch->frame[branch->curframe]->regs;
+		if (BPF_SRC(insn->code) == BPF_K) {
+			mark_reg_unknown(env, regs, insn->dst_reg);
+		} else if (BPF_SRC(insn->code) == BPF_X) {
+			mark_reg_unknown(env, regs, insn->dst_reg);
+			mark_reg_unknown(env, regs, insn->src_reg);
+		}
+	}
+	return branch;
+}
+
+static int sanitize_ptr_alu(struct bpf_verifier_env *env,
+			    struct bpf_insn *insn,
+			    const struct bpf_reg_state *ptr_reg,
+			    const struct bpf_reg_state *off_reg,
+			    struct bpf_reg_state *dst_reg,
+			    struct bpf_sanitize_info *info,
+			    const bool commit_window)
+{
+	struct bpf_insn_aux_data *aux = commit_window ? cur_aux(env) : &info->aux;
+	struct bpf_verifier_state *vstate = env->cur_state;
+	bool off_is_imm = tnum_is_const(off_reg->var_off);
+	bool off_is_neg = off_reg->smin_value < 0;
+	bool ptr_is_dst_reg = ptr_reg == dst_reg;
+	u8 opcode = BPF_OP(insn->code);
+	u32 alu_state, alu_limit;
+	struct bpf_reg_state tmp;
+	bool ret;
+	int err;
+
+	if (can_skip_alu_sanitation(env, insn))
+		return 0;
+
+	/* We already marked aux for masking from non-speculative
+	 * paths, thus we got here in the first place. We only care
+	 * to explore bad access from here.
+	 */
+	if (vstate->speculative)
+		goto do_sim;
+
+	if (!commit_window) {
+		if (!tnum_is_const(off_reg->var_off) &&
+		    (off_reg->smin_value < 0) != (off_reg->smax_value < 0))
+			return REASON_BOUNDS;
+
+		info->mask_to_left = (opcode == BPF_ADD &&  off_is_neg) ||
+				     (opcode == BPF_SUB && !off_is_neg);
+	}
+
+	err = retrieve_ptr_limit(ptr_reg, &alu_limit, info->mask_to_left);
+	if (err < 0)
+		return err;
+
+	if (commit_window) {
+		/* In commit phase we narrow the masking window based on
+		 * the observed pointer move after the simulated operation.
+		 */
+		alu_state = info->aux.alu_state;
+		alu_limit = abs(info->aux.alu_limit - alu_limit);
+	} else {
+		alu_state  = off_is_neg ? BPF_ALU_NEG_VALUE : 0;
+		alu_state |= off_is_imm ? BPF_ALU_IMMEDIATE : 0;
+		alu_state |= ptr_is_dst_reg ?
+			     BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST;
+
+		/* Limit pruning on unknown scalars to enable deep search for
+		 * potential masking differences from other program paths.
+		 */
+		if (!off_is_imm)
+			env->explore_alu_limits = true;
+	}
+
+	err = update_alu_sanitation_state(aux, alu_state, alu_limit);
+	if (err < 0)
+		return err;
+do_sim:
+	/* If we're in commit phase, we're done here given we already
+	 * pushed the truncated dst_reg into the speculative verification
+	 * stack.
+	 *
+	 * Also, when register is a known constant, we rewrite register-based
+	 * operation to immediate-based, and thus do not need masking (and as
+	 * a consequence, do not need to simulate the zero-truncation either).
+	 */
+	if (commit_window || off_is_imm)
+		return 0;
+
+	/* Simulate and find potential out-of-bounds access under
+	 * speculative execution from truncation as a result of
+	 * masking when off was not within expected range. If off
+	 * sits in dst, then we temporarily need to move ptr there
+	 * to simulate dst (== 0) +/-= ptr. Needed, for example,
+	 * for cases where we use K-based arithmetic in one direction
+	 * and truncated reg-based in the other in order to explore
+	 * bad access.
+	 */
+	if (!ptr_is_dst_reg) {
+		tmp = *dst_reg;
+		copy_register_state(dst_reg, ptr_reg);
+	}
+	ret = sanitize_speculative_path(env, NULL, env->insn_idx + 1,
+					env->insn_idx);
+	if (!ptr_is_dst_reg && ret)
+		*dst_reg = tmp;
+	return !ret ? REASON_STACK : 0;
+}
+
+static void sanitize_mark_insn_seen(struct bpf_verifier_env *env)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+
+	/* If we simulate paths under speculation, we don't update the
+	 * insn as 'seen' such that when we verify unreachable paths in
+	 * the non-speculative domain, sanitize_dead_code() can still
+	 * rewrite/sanitize them.
+	 */
+	if (!vstate->speculative)
+		env->insn_aux_data[env->insn_idx].seen = env->pass_cnt;
+}
+
+static int sanitize_err(struct bpf_verifier_env *env,
+			const struct bpf_insn *insn, int reason,
+			const struct bpf_reg_state *off_reg,
+			const struct bpf_reg_state *dst_reg)
+{
+	static const char *err = "pointer arithmetic with it prohibited for !root";
+	const char *op = BPF_OP(insn->code) == BPF_ADD ? "add" : "sub";
+	u32 dst = insn->dst_reg, src = insn->src_reg;
+
+	switch (reason) {
+	case REASON_BOUNDS:
+		verbose(env, "R%d has unknown scalar with mixed signed bounds, %s\n",
+			off_reg == dst_reg ? dst : src, err);
+		break;
+	case REASON_TYPE:
+		verbose(env, "R%d has pointer with unsupported alu operation, %s\n",
+			off_reg == dst_reg ? src : dst, err);
+		break;
+	case REASON_PATHS:
+		verbose(env, "R%d tried to %s from different maps, paths or scalars, %s\n",
+			dst, op, err);
+		break;
+	case REASON_LIMIT:
+		verbose(env, "R%d tried to %s beyond pointer bounds, %s\n",
+			dst, op, err);
+		break;
+	case REASON_STACK:
+		verbose(env, "R%d could not be pushed for speculative verification, %s\n",
+			dst, err);
+		break;
+	default:
+		verbose(env, "verifier internal error: unknown reason (%d)\n",
+			reason);
+		break;
+	}
+
+	return -EACCES;
+}
+
+/* check that stack access falls within stack limits and that 'reg' doesn't
+ * have a variable offset.
+ *
+ * Variable offset is prohibited for unprivileged mode for simplicity since it
+ * requires corresponding support in Spectre masking for stack ALU.  See also
+ * retrieve_ptr_limit().
+ *
+ *
+ * 'off' includes 'reg->off'.
+ */
+static int check_stack_access_for_ptr_arithmetic(
+				struct bpf_verifier_env *env,
+				int regno,
+				const struct bpf_reg_state *reg,
+				int off)
+{
+	if (!tnum_is_const(reg->var_off)) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env, "R%d variable stack access prohibited for !root, var_off=%s off=%d\n",
+			regno, tn_buf, off);
+		return -EACCES;
+	}
+
+	if (off >= 0 || off < -MAX_BPF_STACK) {
+		verbose(env, "R%d stack pointer arithmetic goes out of range, "
+			"prohibited for !root; off=%d\n", regno, off);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+static int sanitize_check_bounds(struct bpf_verifier_env *env,
+				 const struct bpf_insn *insn,
+				 const struct bpf_reg_state *dst_reg)
+{
+	u32 dst = insn->dst_reg;
+
+	/* For unprivileged we require that resulting offset must be in bounds
+	 * in order to be able to sanitize access later on.
+	 */
+	if (env->bypass_spec_v1)
+		return 0;
+
+	switch (dst_reg->type) {
+	case PTR_TO_STACK:
+		if (check_stack_access_for_ptr_arithmetic(env, dst, dst_reg,
+					dst_reg->off + dst_reg->var_off.value))
+			return -EACCES;
+		break;
+	case PTR_TO_MAP_VALUE:
+		if (check_map_access(env, dst, dst_reg->off, 1, false, ACCESS_HELPER)) {
+			verbose(env, "R%d pointer arithmetic of map value goes out of range, "
+				"prohibited for !root\n", dst);
+			return -EACCES;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off.
+ * Caller should also handle BPF_MOV case separately.
+ * If we return -EACCES, caller may want to try again treating pointer as a
+ * scalar.  So we only emit a diagnostic if !env->allow_ptr_leaks.
+ */
+static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
+				   struct bpf_insn *insn,
+				   const struct bpf_reg_state *ptr_reg,
+				   const struct bpf_reg_state *off_reg)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_reg_state *regs = state->regs, *dst_reg;
+	bool known = tnum_is_const(off_reg->var_off);
+	s64 smin_val = off_reg->smin_value, smax_val = off_reg->smax_value,
+	    smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value;
+	u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value,
+	    umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value;
+	struct bpf_sanitize_info info = {};
+	u8 opcode = BPF_OP(insn->code);
+	u32 dst = insn->dst_reg;
+	int ret;
+
+	dst_reg = &regs[dst];
+
+	if ((known && (smin_val != smax_val || umin_val != umax_val)) ||
+	    smin_val > smax_val || umin_val > umax_val) {
+		/* Taint dst register if offset had invalid bounds derived from
+		 * e.g. dead branches.
+		 */
+		__mark_reg_unknown(env, dst_reg);
+		return 0;
+	}
+
+	if (BPF_CLASS(insn->code) != BPF_ALU64) {
+		/* 32-bit ALU ops on pointers produce (meaningless) scalars */
+		if (opcode == BPF_SUB && env->allow_ptr_leaks) {
+			__mark_reg_unknown(env, dst_reg);
+			return 0;
+		}
+
+		verbose(env,
+			"R%d 32-bit pointer arithmetic prohibited\n",
+			dst);
+		return -EACCES;
+	}
+
+	if (ptr_reg->type & PTR_MAYBE_NULL) {
+		verbose(env, "R%d pointer arithmetic on %s prohibited, null-check it first\n",
+			dst, reg_type_str(env, ptr_reg->type));
+		return -EACCES;
+	}
+
+	switch (base_type(ptr_reg->type)) {
+	case PTR_TO_FLOW_KEYS:
+		if (known)
+			break;
+		fallthrough;
+	case CONST_PTR_TO_MAP:
+		/* smin_val represents the known value */
+		if (known && smin_val == 0 && opcode == BPF_ADD)
+			break;
+		fallthrough;
+	case PTR_TO_PACKET_END:
+	case PTR_TO_SOCKET:
+	case PTR_TO_SOCK_COMMON:
+	case PTR_TO_TCP_SOCK:
+	case PTR_TO_XDP_SOCK:
+		verbose(env, "R%d pointer arithmetic on %s prohibited\n",
+			dst, reg_type_str(env, ptr_reg->type));
+		return -EACCES;
+	default:
+		break;
+	}
+
+	/* In case of 'scalar += pointer', dst_reg inherits pointer type and id.
+	 * The id may be overwritten later if we create a new variable offset.
+	 */
+	dst_reg->type = ptr_reg->type;
+	dst_reg->id = ptr_reg->id;
+
+	if (!check_reg_sane_offset(env, off_reg, ptr_reg->type) ||
+	    !check_reg_sane_offset(env, ptr_reg, ptr_reg->type))
+		return -EINVAL;
+
+	/* pointer types do not carry 32-bit bounds at the moment. */
+	__mark_reg32_unbounded(dst_reg);
+
+	if (sanitize_needed(opcode)) {
+		ret = sanitize_ptr_alu(env, insn, ptr_reg, off_reg, dst_reg,
+				       &info, false);
+		if (ret < 0)
+			return sanitize_err(env, insn, ret, off_reg, dst_reg);
+	}
+
+	switch (opcode) {
+	case BPF_ADD:
+		/* We can take a fixed offset as long as it doesn't overflow
+		 * the s32 'off' field
+		 */
+		if (known && (ptr_reg->off + smin_val ==
+			      (s64)(s32)(ptr_reg->off + smin_val))) {
+			/* pointer += K.  Accumulate it into fixed offset */
+			dst_reg->smin_value = smin_ptr;
+			dst_reg->smax_value = smax_ptr;
+			dst_reg->umin_value = umin_ptr;
+			dst_reg->umax_value = umax_ptr;
+			dst_reg->var_off = ptr_reg->var_off;
+			dst_reg->off = ptr_reg->off + smin_val;
+			dst_reg->raw = ptr_reg->raw;
+			break;
+		}
+		/* A new variable offset is created.  Note that off_reg->off
+		 * == 0, since it's a scalar.
+		 * dst_reg gets the pointer type and since some positive
+		 * integer value was added to the pointer, give it a new 'id'
+		 * if it's a PTR_TO_PACKET.
+		 * this creates a new 'base' pointer, off_reg (variable) gets
+		 * added into the variable offset, and we copy the fixed offset
+		 * from ptr_reg.
+		 */
+		if (signed_add_overflows(smin_ptr, smin_val) ||
+		    signed_add_overflows(smax_ptr, smax_val)) {
+			dst_reg->smin_value = S64_MIN;
+			dst_reg->smax_value = S64_MAX;
+		} else {
+			dst_reg->smin_value = smin_ptr + smin_val;
+			dst_reg->smax_value = smax_ptr + smax_val;
+		}
+		if (umin_ptr + umin_val < umin_ptr ||
+		    umax_ptr + umax_val < umax_ptr) {
+			dst_reg->umin_value = 0;
+			dst_reg->umax_value = U64_MAX;
+		} else {
+			dst_reg->umin_value = umin_ptr + umin_val;
+			dst_reg->umax_value = umax_ptr + umax_val;
+		}
+		dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off);
+		dst_reg->off = ptr_reg->off;
+		dst_reg->raw = ptr_reg->raw;
+		if (reg_is_pkt_pointer(ptr_reg)) {
+			dst_reg->id = ++env->id_gen;
+			/* something was added to pkt_ptr, set range to zero */
+			memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
+		}
+		break;
+	case BPF_SUB:
+		if (dst_reg == off_reg) {
+			/* scalar -= pointer.  Creates an unknown scalar */
+			verbose(env, "R%d tried to subtract pointer from scalar\n",
+				dst);
+			return -EACCES;
+		}
+		/* We don't allow subtraction from FP, because (according to
+		 * test_verifier.c test "invalid fp arithmetic", JITs might not
+		 * be able to deal with it.
+		 */
+		if (ptr_reg->type == PTR_TO_STACK) {
+			verbose(env, "R%d subtraction from stack pointer prohibited\n",
+				dst);
+			return -EACCES;
+		}
+		if (known && (ptr_reg->off - smin_val ==
+			      (s64)(s32)(ptr_reg->off - smin_val))) {
+			/* pointer -= K.  Subtract it from fixed offset */
+			dst_reg->smin_value = smin_ptr;
+			dst_reg->smax_value = smax_ptr;
+			dst_reg->umin_value = umin_ptr;
+			dst_reg->umax_value = umax_ptr;
+			dst_reg->var_off = ptr_reg->var_off;
+			dst_reg->id = ptr_reg->id;
+			dst_reg->off = ptr_reg->off - smin_val;
+			dst_reg->raw = ptr_reg->raw;
+			break;
+		}
+		/* A new variable offset is created.  If the subtrahend is known
+		 * nonnegative, then any reg->range we had before is still good.
+		 */
+		if (signed_sub_overflows(smin_ptr, smax_val) ||
+		    signed_sub_overflows(smax_ptr, smin_val)) {
+			/* Overflow possible, we know nothing */
+			dst_reg->smin_value = S64_MIN;
+			dst_reg->smax_value = S64_MAX;
+		} else {
+			dst_reg->smin_value = smin_ptr - smax_val;
+			dst_reg->smax_value = smax_ptr - smin_val;
+		}
+		if (umin_ptr < umax_val) {
+			/* Overflow possible, we know nothing */
+			dst_reg->umin_value = 0;
+			dst_reg->umax_value = U64_MAX;
+		} else {
+			/* Cannot overflow (as long as bounds are consistent) */
+			dst_reg->umin_value = umin_ptr - umax_val;
+			dst_reg->umax_value = umax_ptr - umin_val;
+		}
+		dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off);
+		dst_reg->off = ptr_reg->off;
+		dst_reg->raw = ptr_reg->raw;
+		if (reg_is_pkt_pointer(ptr_reg)) {
+			dst_reg->id = ++env->id_gen;
+			/* something was added to pkt_ptr, set range to zero */
+			if (smin_val < 0)
+				memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
+		}
+		break;
+	case BPF_AND:
+	case BPF_OR:
+	case BPF_XOR:
+		/* bitwise ops on pointers are troublesome, prohibit. */
+		verbose(env, "R%d bitwise operator %s on pointer prohibited\n",
+			dst, bpf_alu_string[opcode >> 4]);
+		return -EACCES;
+	default:
+		/* other operators (e.g. MUL,LSH) produce non-pointer results */
+		verbose(env, "R%d pointer arithmetic with %s operator prohibited\n",
+			dst, bpf_alu_string[opcode >> 4]);
+		return -EACCES;
+	}
+
+	if (!check_reg_sane_offset(env, dst_reg, ptr_reg->type))
+		return -EINVAL;
+	reg_bounds_sync(dst_reg);
+	if (sanitize_check_bounds(env, insn, dst_reg) < 0)
+		return -EACCES;
+	if (sanitize_needed(opcode)) {
+		ret = sanitize_ptr_alu(env, insn, dst_reg, off_reg, dst_reg,
+				       &info, true);
+		if (ret < 0)
+			return sanitize_err(env, insn, ret, off_reg, dst_reg);
+	}
+
+	return 0;
+}
+
+static void scalar32_min_max_add(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	s32 smin_val = src_reg->s32_min_value;
+	s32 smax_val = src_reg->s32_max_value;
+	u32 umin_val = src_reg->u32_min_value;
+	u32 umax_val = src_reg->u32_max_value;
+
+	if (signed_add32_overflows(dst_reg->s32_min_value, smin_val) ||
+	    signed_add32_overflows(dst_reg->s32_max_value, smax_val)) {
+		dst_reg->s32_min_value = S32_MIN;
+		dst_reg->s32_max_value = S32_MAX;
+	} else {
+		dst_reg->s32_min_value += smin_val;
+		dst_reg->s32_max_value += smax_val;
+	}
+	if (dst_reg->u32_min_value + umin_val < umin_val ||
+	    dst_reg->u32_max_value + umax_val < umax_val) {
+		dst_reg->u32_min_value = 0;
+		dst_reg->u32_max_value = U32_MAX;
+	} else {
+		dst_reg->u32_min_value += umin_val;
+		dst_reg->u32_max_value += umax_val;
+	}
+}
+
+static void scalar_min_max_add(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	s64 smin_val = src_reg->smin_value;
+	s64 smax_val = src_reg->smax_value;
+	u64 umin_val = src_reg->umin_value;
+	u64 umax_val = src_reg->umax_value;
+
+	if (signed_add_overflows(dst_reg->smin_value, smin_val) ||
+	    signed_add_overflows(dst_reg->smax_value, smax_val)) {
+		dst_reg->smin_value = S64_MIN;
+		dst_reg->smax_value = S64_MAX;
+	} else {
+		dst_reg->smin_value += smin_val;
+		dst_reg->smax_value += smax_val;
+	}
+	if (dst_reg->umin_value + umin_val < umin_val ||
+	    dst_reg->umax_value + umax_val < umax_val) {
+		dst_reg->umin_value = 0;
+		dst_reg->umax_value = U64_MAX;
+	} else {
+		dst_reg->umin_value += umin_val;
+		dst_reg->umax_value += umax_val;
+	}
+}
+
+static void scalar32_min_max_sub(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	s32 smin_val = src_reg->s32_min_value;
+	s32 smax_val = src_reg->s32_max_value;
+	u32 umin_val = src_reg->u32_min_value;
+	u32 umax_val = src_reg->u32_max_value;
+
+	if (signed_sub32_overflows(dst_reg->s32_min_value, smax_val) ||
+	    signed_sub32_overflows(dst_reg->s32_max_value, smin_val)) {
+		/* Overflow possible, we know nothing */
+		dst_reg->s32_min_value = S32_MIN;
+		dst_reg->s32_max_value = S32_MAX;
+	} else {
+		dst_reg->s32_min_value -= smax_val;
+		dst_reg->s32_max_value -= smin_val;
+	}
+	if (dst_reg->u32_min_value < umax_val) {
+		/* Overflow possible, we know nothing */
+		dst_reg->u32_min_value = 0;
+		dst_reg->u32_max_value = U32_MAX;
+	} else {
+		/* Cannot overflow (as long as bounds are consistent) */
+		dst_reg->u32_min_value -= umax_val;
+		dst_reg->u32_max_value -= umin_val;
+	}
+}
+
+static void scalar_min_max_sub(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	s64 smin_val = src_reg->smin_value;
+	s64 smax_val = src_reg->smax_value;
+	u64 umin_val = src_reg->umin_value;
+	u64 umax_val = src_reg->umax_value;
+
+	if (signed_sub_overflows(dst_reg->smin_value, smax_val) ||
+	    signed_sub_overflows(dst_reg->smax_value, smin_val)) {
+		/* Overflow possible, we know nothing */
+		dst_reg->smin_value = S64_MIN;
+		dst_reg->smax_value = S64_MAX;
+	} else {
+		dst_reg->smin_value -= smax_val;
+		dst_reg->smax_value -= smin_val;
+	}
+	if (dst_reg->umin_value < umax_val) {
+		/* Overflow possible, we know nothing */
+		dst_reg->umin_value = 0;
+		dst_reg->umax_value = U64_MAX;
+	} else {
+		/* Cannot overflow (as long as bounds are consistent) */
+		dst_reg->umin_value -= umax_val;
+		dst_reg->umax_value -= umin_val;
+	}
+}
+
+static void scalar32_min_max_mul(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	s32 smin_val = src_reg->s32_min_value;
+	u32 umin_val = src_reg->u32_min_value;
+	u32 umax_val = src_reg->u32_max_value;
+
+	if (smin_val < 0 || dst_reg->s32_min_value < 0) {
+		/* Ain't nobody got time to multiply that sign */
+		__mark_reg32_unbounded(dst_reg);
+		return;
+	}
+	/* Both values are positive, so we can work with unsigned and
+	 * copy the result to signed (unless it exceeds S32_MAX).
+	 */
+	if (umax_val > U16_MAX || dst_reg->u32_max_value > U16_MAX) {
+		/* Potential overflow, we know nothing */
+		__mark_reg32_unbounded(dst_reg);
+		return;
+	}
+	dst_reg->u32_min_value *= umin_val;
+	dst_reg->u32_max_value *= umax_val;
+	if (dst_reg->u32_max_value > S32_MAX) {
+		/* Overflow possible, we know nothing */
+		dst_reg->s32_min_value = S32_MIN;
+		dst_reg->s32_max_value = S32_MAX;
+	} else {
+		dst_reg->s32_min_value = dst_reg->u32_min_value;
+		dst_reg->s32_max_value = dst_reg->u32_max_value;
+	}
+}
+
+static void scalar_min_max_mul(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	s64 smin_val = src_reg->smin_value;
+	u64 umin_val = src_reg->umin_value;
+	u64 umax_val = src_reg->umax_value;
+
+	if (smin_val < 0 || dst_reg->smin_value < 0) {
+		/* Ain't nobody got time to multiply that sign */
+		__mark_reg64_unbounded(dst_reg);
+		return;
+	}
+	/* Both values are positive, so we can work with unsigned and
+	 * copy the result to signed (unless it exceeds S64_MAX).
+	 */
+	if (umax_val > U32_MAX || dst_reg->umax_value > U32_MAX) {
+		/* Potential overflow, we know nothing */
+		__mark_reg64_unbounded(dst_reg);
+		return;
+	}
+	dst_reg->umin_value *= umin_val;
+	dst_reg->umax_value *= umax_val;
+	if (dst_reg->umax_value > S64_MAX) {
+		/* Overflow possible, we know nothing */
+		dst_reg->smin_value = S64_MIN;
+		dst_reg->smax_value = S64_MAX;
+	} else {
+		dst_reg->smin_value = dst_reg->umin_value;
+		dst_reg->smax_value = dst_reg->umax_value;
+	}
+}
+
+static void scalar32_min_max_and(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	bool src_known = tnum_subreg_is_const(src_reg->var_off);
+	bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
+	struct tnum var32_off = tnum_subreg(dst_reg->var_off);
+	s32 smin_val = src_reg->s32_min_value;
+	u32 umax_val = src_reg->u32_max_value;
+
+	if (src_known && dst_known) {
+		__mark_reg32_known(dst_reg, var32_off.value);
+		return;
+	}
+
+	/* We get our minimum from the var_off, since that's inherently
+	 * bitwise.  Our maximum is the minimum of the operands' maxima.
+	 */
+	dst_reg->u32_min_value = var32_off.value;
+	dst_reg->u32_max_value = min(dst_reg->u32_max_value, umax_val);
+	if (dst_reg->s32_min_value < 0 || smin_val < 0) {
+		/* Lose signed bounds when ANDing negative numbers,
+		 * ain't nobody got time for that.
+		 */
+		dst_reg->s32_min_value = S32_MIN;
+		dst_reg->s32_max_value = S32_MAX;
+	} else {
+		/* ANDing two positives gives a positive, so safe to
+		 * cast result into s64.
+		 */
+		dst_reg->s32_min_value = dst_reg->u32_min_value;
+		dst_reg->s32_max_value = dst_reg->u32_max_value;
+	}
+}
+
+static void scalar_min_max_and(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	bool src_known = tnum_is_const(src_reg->var_off);
+	bool dst_known = tnum_is_const(dst_reg->var_off);
+	s64 smin_val = src_reg->smin_value;
+	u64 umax_val = src_reg->umax_value;
+
+	if (src_known && dst_known) {
+		__mark_reg_known(dst_reg, dst_reg->var_off.value);
+		return;
+	}
+
+	/* We get our minimum from the var_off, since that's inherently
+	 * bitwise.  Our maximum is the minimum of the operands' maxima.
+	 */
+	dst_reg->umin_value = dst_reg->var_off.value;
+	dst_reg->umax_value = min(dst_reg->umax_value, umax_val);
+	if (dst_reg->smin_value < 0 || smin_val < 0) {
+		/* Lose signed bounds when ANDing negative numbers,
+		 * ain't nobody got time for that.
+		 */
+		dst_reg->smin_value = S64_MIN;
+		dst_reg->smax_value = S64_MAX;
+	} else {
+		/* ANDing two positives gives a positive, so safe to
+		 * cast result into s64.
+		 */
+		dst_reg->smin_value = dst_reg->umin_value;
+		dst_reg->smax_value = dst_reg->umax_value;
+	}
+	/* We may learn something more from the var_off */
+	__update_reg_bounds(dst_reg);
+}
+
+static void scalar32_min_max_or(struct bpf_reg_state *dst_reg,
+				struct bpf_reg_state *src_reg)
+{
+	bool src_known = tnum_subreg_is_const(src_reg->var_off);
+	bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
+	struct tnum var32_off = tnum_subreg(dst_reg->var_off);
+	s32 smin_val = src_reg->s32_min_value;
+	u32 umin_val = src_reg->u32_min_value;
+
+	if (src_known && dst_known) {
+		__mark_reg32_known(dst_reg, var32_off.value);
+		return;
+	}
+
+	/* We get our maximum from the var_off, and our minimum is the
+	 * maximum of the operands' minima
+	 */
+	dst_reg->u32_min_value = max(dst_reg->u32_min_value, umin_val);
+	dst_reg->u32_max_value = var32_off.value | var32_off.mask;
+	if (dst_reg->s32_min_value < 0 || smin_val < 0) {
+		/* Lose signed bounds when ORing negative numbers,
+		 * ain't nobody got time for that.
+		 */
+		dst_reg->s32_min_value = S32_MIN;
+		dst_reg->s32_max_value = S32_MAX;
+	} else {
+		/* ORing two positives gives a positive, so safe to
+		 * cast result into s64.
+		 */
+		dst_reg->s32_min_value = dst_reg->u32_min_value;
+		dst_reg->s32_max_value = dst_reg->u32_max_value;
+	}
+}
+
+static void scalar_min_max_or(struct bpf_reg_state *dst_reg,
+			      struct bpf_reg_state *src_reg)
+{
+	bool src_known = tnum_is_const(src_reg->var_off);
+	bool dst_known = tnum_is_const(dst_reg->var_off);
+	s64 smin_val = src_reg->smin_value;
+	u64 umin_val = src_reg->umin_value;
+
+	if (src_known && dst_known) {
+		__mark_reg_known(dst_reg, dst_reg->var_off.value);
+		return;
+	}
+
+	/* We get our maximum from the var_off, and our minimum is the
+	 * maximum of the operands' minima
+	 */
+	dst_reg->umin_value = max(dst_reg->umin_value, umin_val);
+	dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask;
+	if (dst_reg->smin_value < 0 || smin_val < 0) {
+		/* Lose signed bounds when ORing negative numbers,
+		 * ain't nobody got time for that.
+		 */
+		dst_reg->smin_value = S64_MIN;
+		dst_reg->smax_value = S64_MAX;
+	} else {
+		/* ORing two positives gives a positive, so safe to
+		 * cast result into s64.
+		 */
+		dst_reg->smin_value = dst_reg->umin_value;
+		dst_reg->smax_value = dst_reg->umax_value;
+	}
+	/* We may learn something more from the var_off */
+	__update_reg_bounds(dst_reg);
+}
+
+static void scalar32_min_max_xor(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	bool src_known = tnum_subreg_is_const(src_reg->var_off);
+	bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
+	struct tnum var32_off = tnum_subreg(dst_reg->var_off);
+	s32 smin_val = src_reg->s32_min_value;
+
+	if (src_known && dst_known) {
+		__mark_reg32_known(dst_reg, var32_off.value);
+		return;
+	}
+
+	/* We get both minimum and maximum from the var32_off. */
+	dst_reg->u32_min_value = var32_off.value;
+	dst_reg->u32_max_value = var32_off.value | var32_off.mask;
+
+	if (dst_reg->s32_min_value >= 0 && smin_val >= 0) {
+		/* XORing two positive sign numbers gives a positive,
+		 * so safe to cast u32 result into s32.
+		 */
+		dst_reg->s32_min_value = dst_reg->u32_min_value;
+		dst_reg->s32_max_value = dst_reg->u32_max_value;
+	} else {
+		dst_reg->s32_min_value = S32_MIN;
+		dst_reg->s32_max_value = S32_MAX;
+	}
+}
+
+static void scalar_min_max_xor(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	bool src_known = tnum_is_const(src_reg->var_off);
+	bool dst_known = tnum_is_const(dst_reg->var_off);
+	s64 smin_val = src_reg->smin_value;
+
+	if (src_known && dst_known) {
+		/* dst_reg->var_off.value has been updated earlier */
+		__mark_reg_known(dst_reg, dst_reg->var_off.value);
+		return;
+	}
+
+	/* We get both minimum and maximum from the var_off. */
+	dst_reg->umin_value = dst_reg->var_off.value;
+	dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask;
+
+	if (dst_reg->smin_value >= 0 && smin_val >= 0) {
+		/* XORing two positive sign numbers gives a positive,
+		 * so safe to cast u64 result into s64.
+		 */
+		dst_reg->smin_value = dst_reg->umin_value;
+		dst_reg->smax_value = dst_reg->umax_value;
+	} else {
+		dst_reg->smin_value = S64_MIN;
+		dst_reg->smax_value = S64_MAX;
+	}
+
+	__update_reg_bounds(dst_reg);
+}
+
+static void __scalar32_min_max_lsh(struct bpf_reg_state *dst_reg,
+				   u64 umin_val, u64 umax_val)
+{
+	/* We lose all sign bit information (except what we can pick
+	 * up from var_off)
+	 */
+	dst_reg->s32_min_value = S32_MIN;
+	dst_reg->s32_max_value = S32_MAX;
+	/* If we might shift our top bit out, then we know nothing */
+	if (umax_val > 31 || dst_reg->u32_max_value > 1ULL << (31 - umax_val)) {
+		dst_reg->u32_min_value = 0;
+		dst_reg->u32_max_value = U32_MAX;
+	} else {
+		dst_reg->u32_min_value <<= umin_val;
+		dst_reg->u32_max_value <<= umax_val;
+	}
+}
+
+static void scalar32_min_max_lsh(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	u32 umax_val = src_reg->u32_max_value;
+	u32 umin_val = src_reg->u32_min_value;
+	/* u32 alu operation will zext upper bits */
+	struct tnum subreg = tnum_subreg(dst_reg->var_off);
+
+	__scalar32_min_max_lsh(dst_reg, umin_val, umax_val);
+	dst_reg->var_off = tnum_subreg(tnum_lshift(subreg, umin_val));
+	/* Not required but being careful mark reg64 bounds as unknown so
+	 * that we are forced to pick them up from tnum and zext later and
+	 * if some path skips this step we are still safe.
+	 */
+	__mark_reg64_unbounded(dst_reg);
+	__update_reg32_bounds(dst_reg);
+}
+
+static void __scalar64_min_max_lsh(struct bpf_reg_state *dst_reg,
+				   u64 umin_val, u64 umax_val)
+{
+	/* Special case <<32 because it is a common compiler pattern to sign
+	 * extend subreg by doing <<32 s>>32. In this case if 32bit bounds are
+	 * positive we know this shift will also be positive so we can track
+	 * bounds correctly. Otherwise we lose all sign bit information except
+	 * what we can pick up from var_off. Perhaps we can generalize this
+	 * later to shifts of any length.
+	 */
+	if (umin_val == 32 && umax_val == 32 && dst_reg->s32_max_value >= 0)
+		dst_reg->smax_value = (s64)dst_reg->s32_max_value << 32;
+	else
+		dst_reg->smax_value = S64_MAX;
+
+	if (umin_val == 32 && umax_val == 32 && dst_reg->s32_min_value >= 0)
+		dst_reg->smin_value = (s64)dst_reg->s32_min_value << 32;
+	else
+		dst_reg->smin_value = S64_MIN;
+
+	/* If we might shift our top bit out, then we know nothing */
+	if (dst_reg->umax_value > 1ULL << (63 - umax_val)) {
+		dst_reg->umin_value = 0;
+		dst_reg->umax_value = U64_MAX;
+	} else {
+		dst_reg->umin_value <<= umin_val;
+		dst_reg->umax_value <<= umax_val;
+	}
+}
+
+static void scalar_min_max_lsh(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	u64 umax_val = src_reg->umax_value;
+	u64 umin_val = src_reg->umin_value;
+
+	/* scalar64 calc uses 32bit unshifted bounds so must be called first */
+	__scalar64_min_max_lsh(dst_reg, umin_val, umax_val);
+	__scalar32_min_max_lsh(dst_reg, umin_val, umax_val);
+
+	dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val);
+	/* We may learn something more from the var_off */
+	__update_reg_bounds(dst_reg);
+}
+
+static void scalar32_min_max_rsh(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	struct tnum subreg = tnum_subreg(dst_reg->var_off);
+	u32 umax_val = src_reg->u32_max_value;
+	u32 umin_val = src_reg->u32_min_value;
+
+	/* BPF_RSH is an unsigned shift.  If the value in dst_reg might
+	 * be negative, then either:
+	 * 1) src_reg might be zero, so the sign bit of the result is
+	 *    unknown, so we lose our signed bounds
+	 * 2) it's known negative, thus the unsigned bounds capture the
+	 *    signed bounds
+	 * 3) the signed bounds cross zero, so they tell us nothing
+	 *    about the result
+	 * If the value in dst_reg is known nonnegative, then again the
+	 * unsigned bounds capture the signed bounds.
+	 * Thus, in all cases it suffices to blow away our signed bounds
+	 * and rely on inferring new ones from the unsigned bounds and
+	 * var_off of the result.
+	 */
+	dst_reg->s32_min_value = S32_MIN;
+	dst_reg->s32_max_value = S32_MAX;
+
+	dst_reg->var_off = tnum_rshift(subreg, umin_val);
+	dst_reg->u32_min_value >>= umax_val;
+	dst_reg->u32_max_value >>= umin_val;
+
+	__mark_reg64_unbounded(dst_reg);
+	__update_reg32_bounds(dst_reg);
+}
+
+static void scalar_min_max_rsh(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	u64 umax_val = src_reg->umax_value;
+	u64 umin_val = src_reg->umin_value;
+
+	/* BPF_RSH is an unsigned shift.  If the value in dst_reg might
+	 * be negative, then either:
+	 * 1) src_reg might be zero, so the sign bit of the result is
+	 *    unknown, so we lose our signed bounds
+	 * 2) it's known negative, thus the unsigned bounds capture the
+	 *    signed bounds
+	 * 3) the signed bounds cross zero, so they tell us nothing
+	 *    about the result
+	 * If the value in dst_reg is known nonnegative, then again the
+	 * unsigned bounds capture the signed bounds.
+	 * Thus, in all cases it suffices to blow away our signed bounds
+	 * and rely on inferring new ones from the unsigned bounds and
+	 * var_off of the result.
+	 */
+	dst_reg->smin_value = S64_MIN;
+	dst_reg->smax_value = S64_MAX;
+	dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val);
+	dst_reg->umin_value >>= umax_val;
+	dst_reg->umax_value >>= umin_val;
+
+	/* Its not easy to operate on alu32 bounds here because it depends
+	 * on bits being shifted in. Take easy way out and mark unbounded
+	 * so we can recalculate later from tnum.
+	 */
+	__mark_reg32_unbounded(dst_reg);
+	__update_reg_bounds(dst_reg);
+}
+
+static void scalar32_min_max_arsh(struct bpf_reg_state *dst_reg,
+				  struct bpf_reg_state *src_reg)
+{
+	u64 umin_val = src_reg->u32_min_value;
+
+	/* Upon reaching here, src_known is true and
+	 * umax_val is equal to umin_val.
+	 */
+	dst_reg->s32_min_value = (u32)(((s32)dst_reg->s32_min_value) >> umin_val);
+	dst_reg->s32_max_value = (u32)(((s32)dst_reg->s32_max_value) >> umin_val);
+
+	dst_reg->var_off = tnum_arshift(tnum_subreg(dst_reg->var_off), umin_val, 32);
+
+	/* blow away the dst_reg umin_value/umax_value and rely on
+	 * dst_reg var_off to refine the result.
+	 */
+	dst_reg->u32_min_value = 0;
+	dst_reg->u32_max_value = U32_MAX;
+
+	__mark_reg64_unbounded(dst_reg);
+	__update_reg32_bounds(dst_reg);
+}
+
+static void scalar_min_max_arsh(struct bpf_reg_state *dst_reg,
+				struct bpf_reg_state *src_reg)
+{
+	u64 umin_val = src_reg->umin_value;
+
+	/* Upon reaching here, src_known is true and umax_val is equal
+	 * to umin_val.
+	 */
+	dst_reg->smin_value >>= umin_val;
+	dst_reg->smax_value >>= umin_val;
+
+	dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val, 64);
+
+	/* blow away the dst_reg umin_value/umax_value and rely on
+	 * dst_reg var_off to refine the result.
+	 */
+	dst_reg->umin_value = 0;
+	dst_reg->umax_value = U64_MAX;
+
+	/* Its not easy to operate on alu32 bounds here because it depends
+	 * on bits being shifted in from upper 32-bits. Take easy way out
+	 * and mark unbounded so we can recalculate later from tnum.
+	 */
+	__mark_reg32_unbounded(dst_reg);
+	__update_reg_bounds(dst_reg);
+}
+
+/* WARNING: This function does calculations on 64-bit values, but the actual
+ * execution may occur on 32-bit values. Therefore, things like bitshifts
+ * need extra checks in the 32-bit case.
+ */
+static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
+				      struct bpf_insn *insn,
+				      struct bpf_reg_state *dst_reg,
+				      struct bpf_reg_state src_reg)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	u8 opcode = BPF_OP(insn->code);
+	bool src_known;
+	s64 smin_val, smax_val;
+	u64 umin_val, umax_val;
+	s32 s32_min_val, s32_max_val;
+	u32 u32_min_val, u32_max_val;
+	u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32;
+	bool alu32 = (BPF_CLASS(insn->code) != BPF_ALU64);
+	int ret;
+
+	smin_val = src_reg.smin_value;
+	smax_val = src_reg.smax_value;
+	umin_val = src_reg.umin_value;
+	umax_val = src_reg.umax_value;
+
+	s32_min_val = src_reg.s32_min_value;
+	s32_max_val = src_reg.s32_max_value;
+	u32_min_val = src_reg.u32_min_value;
+	u32_max_val = src_reg.u32_max_value;
+
+	if (alu32) {
+		src_known = tnum_subreg_is_const(src_reg.var_off);
+		if ((src_known &&
+		     (s32_min_val != s32_max_val || u32_min_val != u32_max_val)) ||
+		    s32_min_val > s32_max_val || u32_min_val > u32_max_val) {
+			/* Taint dst register if offset had invalid bounds
+			 * derived from e.g. dead branches.
+			 */
+			__mark_reg_unknown(env, dst_reg);
+			return 0;
+		}
+	} else {
+		src_known = tnum_is_const(src_reg.var_off);
+		if ((src_known &&
+		     (smin_val != smax_val || umin_val != umax_val)) ||
+		    smin_val > smax_val || umin_val > umax_val) {
+			/* Taint dst register if offset had invalid bounds
+			 * derived from e.g. dead branches.
+			 */
+			__mark_reg_unknown(env, dst_reg);
+			return 0;
+		}
+	}
+
+	if (!src_known &&
+	    opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) {
+		__mark_reg_unknown(env, dst_reg);
+		return 0;
+	}
+
+	if (sanitize_needed(opcode)) {
+		ret = sanitize_val_alu(env, insn);
+		if (ret < 0)
+			return sanitize_err(env, insn, ret, NULL, NULL);
+	}
+
+	/* Calculate sign/unsigned bounds and tnum for alu32 and alu64 bit ops.
+	 * There are two classes of instructions: The first class we track both
+	 * alu32 and alu64 sign/unsigned bounds independently this provides the
+	 * greatest amount of precision when alu operations are mixed with jmp32
+	 * operations. These operations are BPF_ADD, BPF_SUB, BPF_MUL, BPF_ADD,
+	 * and BPF_OR. This is possible because these ops have fairly easy to
+	 * understand and calculate behavior in both 32-bit and 64-bit alu ops.
+	 * See alu32 verifier tests for examples. The second class of
+	 * operations, BPF_LSH, BPF_RSH, and BPF_ARSH, however are not so easy
+	 * with regards to tracking sign/unsigned bounds because the bits may
+	 * cross subreg boundaries in the alu64 case. When this happens we mark
+	 * the reg unbounded in the subreg bound space and use the resulting
+	 * tnum to calculate an approximation of the sign/unsigned bounds.
+	 */
+	switch (opcode) {
+	case BPF_ADD:
+		scalar32_min_max_add(dst_reg, &src_reg);
+		scalar_min_max_add(dst_reg, &src_reg);
+		dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off);
+		break;
+	case BPF_SUB:
+		scalar32_min_max_sub(dst_reg, &src_reg);
+		scalar_min_max_sub(dst_reg, &src_reg);
+		dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off);
+		break;
+	case BPF_MUL:
+		dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off);
+		scalar32_min_max_mul(dst_reg, &src_reg);
+		scalar_min_max_mul(dst_reg, &src_reg);
+		break;
+	case BPF_AND:
+		dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg.var_off);
+		scalar32_min_max_and(dst_reg, &src_reg);
+		scalar_min_max_and(dst_reg, &src_reg);
+		break;
+	case BPF_OR:
+		dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg.var_off);
+		scalar32_min_max_or(dst_reg, &src_reg);
+		scalar_min_max_or(dst_reg, &src_reg);
+		break;
+	case BPF_XOR:
+		dst_reg->var_off = tnum_xor(dst_reg->var_off, src_reg.var_off);
+		scalar32_min_max_xor(dst_reg, &src_reg);
+		scalar_min_max_xor(dst_reg, &src_reg);
+		break;
+	case BPF_LSH:
+		if (umax_val >= insn_bitness) {
+			/* Shifts greater than 31 or 63 are undefined.
+			 * This includes shifts by a negative number.
+			 */
+			mark_reg_unknown(env, regs, insn->dst_reg);
+			break;
+		}
+		if (alu32)
+			scalar32_min_max_lsh(dst_reg, &src_reg);
+		else
+			scalar_min_max_lsh(dst_reg, &src_reg);
+		break;
+	case BPF_RSH:
+		if (umax_val >= insn_bitness) {
+			/* Shifts greater than 31 or 63 are undefined.
+			 * This includes shifts by a negative number.
+			 */
+			mark_reg_unknown(env, regs, insn->dst_reg);
+			break;
+		}
+		if (alu32)
+			scalar32_min_max_rsh(dst_reg, &src_reg);
+		else
+			scalar_min_max_rsh(dst_reg, &src_reg);
+		break;
+	case BPF_ARSH:
+		if (umax_val >= insn_bitness) {
+			/* Shifts greater than 31 or 63 are undefined.
+			 * This includes shifts by a negative number.
+			 */
+			mark_reg_unknown(env, regs, insn->dst_reg);
+			break;
+		}
+		if (alu32)
+			scalar32_min_max_arsh(dst_reg, &src_reg);
+		else
+			scalar_min_max_arsh(dst_reg, &src_reg);
+		break;
+	default:
+		mark_reg_unknown(env, regs, insn->dst_reg);
+		break;
+	}
+
+	/* ALU32 ops are zero extended into 64bit register */
+	if (alu32)
+		zext_32_to_64(dst_reg);
+	reg_bounds_sync(dst_reg);
+	return 0;
+}
+
+/* Handles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max
+ * and var_off.
+ */
+static int adjust_reg_min_max_vals(struct bpf_verifier_env *env,
+				   struct bpf_insn *insn)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_reg_state *regs = state->regs, *dst_reg, *src_reg;
+	struct bpf_reg_state *ptr_reg = NULL, off_reg = {0};
+	u8 opcode = BPF_OP(insn->code);
+	int err;
+
+	dst_reg = &regs[insn->dst_reg];
+	src_reg = NULL;
+	if (dst_reg->type != SCALAR_VALUE)
+		ptr_reg = dst_reg;
+	else
+		/* Make sure ID is cleared otherwise dst_reg min/max could be
+		 * incorrectly propagated into other registers by find_equal_scalars()
+		 */
+		dst_reg->id = 0;
+	if (BPF_SRC(insn->code) == BPF_X) {
+		src_reg = &regs[insn->src_reg];
+		if (src_reg->type != SCALAR_VALUE) {
+			if (dst_reg->type != SCALAR_VALUE) {
+				/* Combining two pointers by any ALU op yields
+				 * an arbitrary scalar. Disallow all math except
+				 * pointer subtraction
+				 */
+				if (opcode == BPF_SUB && env->allow_ptr_leaks) {
+					mark_reg_unknown(env, regs, insn->dst_reg);
+					return 0;
+				}
+				verbose(env, "R%d pointer %s pointer prohibited\n",
+					insn->dst_reg,
+					bpf_alu_string[opcode >> 4]);
+				return -EACCES;
+			} else {
+				/* scalar += pointer
+				 * This is legal, but we have to reverse our
+				 * src/dest handling in computing the range
+				 */
+				err = mark_chain_precision(env, insn->dst_reg);
+				if (err)
+					return err;
+				return adjust_ptr_min_max_vals(env, insn,
+							       src_reg, dst_reg);
+			}
+		} else if (ptr_reg) {
+			/* pointer += scalar */
+			err = mark_chain_precision(env, insn->src_reg);
+			if (err)
+				return err;
+			return adjust_ptr_min_max_vals(env, insn,
+						       dst_reg, src_reg);
+		} else if (dst_reg->precise) {
+			/* if dst_reg is precise, src_reg should be precise as well */
+			err = mark_chain_precision(env, insn->src_reg);
+			if (err)
+				return err;
+		}
+	} else {
+		/* Pretend the src is a reg with a known value, since we only
+		 * need to be able to read from this state.
+		 */
+		off_reg.type = SCALAR_VALUE;
+		__mark_reg_known(&off_reg, insn->imm);
+		src_reg = &off_reg;
+		if (ptr_reg) /* pointer += K */
+			return adjust_ptr_min_max_vals(env, insn,
+						       ptr_reg, src_reg);
+	}
+
+	/* Got here implies adding two SCALAR_VALUEs */
+	if (WARN_ON_ONCE(ptr_reg)) {
+		print_verifier_state(env, state, true);
+		verbose(env, "verifier internal error: unexpected ptr_reg\n");
+		return -EINVAL;
+	}
+	if (WARN_ON(!src_reg)) {
+		print_verifier_state(env, state, true);
+		verbose(env, "verifier internal error: no src_reg\n");
+		return -EINVAL;
+	}
+	return adjust_scalar_min_max_vals(env, insn, dst_reg, *src_reg);
+}
+
+/* check validity of 32-bit and 64-bit arithmetic operations */
+static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	u8 opcode = BPF_OP(insn->code);
+	int err;
+
+	if (opcode == BPF_END || opcode == BPF_NEG) {
+		if (opcode == BPF_NEG) {
+			if (BPF_SRC(insn->code) != BPF_K ||
+			    insn->src_reg != BPF_REG_0 ||
+			    insn->off != 0 || insn->imm != 0) {
+				verbose(env, "BPF_NEG uses reserved fields\n");
+				return -EINVAL;
+			}
+		} else {
+			if (insn->src_reg != BPF_REG_0 || insn->off != 0 ||
+			    (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) ||
+			    BPF_CLASS(insn->code) == BPF_ALU64) {
+				verbose(env, "BPF_END uses reserved fields\n");
+				return -EINVAL;
+			}
+		}
+
+		/* check src operand */
+		err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+		if (err)
+			return err;
+
+		if (is_pointer_value(env, insn->dst_reg)) {
+			verbose(env, "R%d pointer arithmetic prohibited\n",
+				insn->dst_reg);
+			return -EACCES;
+		}
+
+		/* check dest operand */
+		err = check_reg_arg(env, insn->dst_reg, DST_OP);
+		if (err)
+			return err;
+
+	} else if (opcode == BPF_MOV) {
+
+		if (BPF_SRC(insn->code) == BPF_X) {
+			if (insn->imm != 0 || insn->off != 0) {
+				verbose(env, "BPF_MOV uses reserved fields\n");
+				return -EINVAL;
+			}
+
+			/* check src operand */
+			err = check_reg_arg(env, insn->src_reg, SRC_OP);
+			if (err)
+				return err;
+		} else {
+			if (insn->src_reg != BPF_REG_0 || insn->off != 0) {
+				verbose(env, "BPF_MOV uses reserved fields\n");
+				return -EINVAL;
+			}
+		}
+
+		/* check dest operand, mark as required later */
+		err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
+		if (err)
+			return err;
+
+		if (BPF_SRC(insn->code) == BPF_X) {
+			struct bpf_reg_state *src_reg = regs + insn->src_reg;
+			struct bpf_reg_state *dst_reg = regs + insn->dst_reg;
+
+			if (BPF_CLASS(insn->code) == BPF_ALU64) {
+				/* case: R1 = R2
+				 * copy register state to dest reg
+				 */
+				if (src_reg->type == SCALAR_VALUE && !src_reg->id)
+					/* Assign src and dst registers the same ID
+					 * that will be used by find_equal_scalars()
+					 * to propagate min/max range.
+					 */
+					src_reg->id = ++env->id_gen;
+				copy_register_state(dst_reg, src_reg);
+				dst_reg->live |= REG_LIVE_WRITTEN;
+				dst_reg->subreg_def = DEF_NOT_SUBREG;
+			} else {
+				/* R1 = (u32) R2 */
+				if (is_pointer_value(env, insn->src_reg)) {
+					verbose(env,
+						"R%d partial copy of pointer\n",
+						insn->src_reg);
+					return -EACCES;
+				} else if (src_reg->type == SCALAR_VALUE) {
+					copy_register_state(dst_reg, src_reg);
+					/* Make sure ID is cleared otherwise
+					 * dst_reg min/max could be incorrectly
+					 * propagated into src_reg by find_equal_scalars()
+					 */
+					dst_reg->id = 0;
+					dst_reg->live |= REG_LIVE_WRITTEN;
+					dst_reg->subreg_def = env->insn_idx + 1;
+				} else {
+					mark_reg_unknown(env, regs,
+							 insn->dst_reg);
+				}
+				zext_32_to_64(dst_reg);
+				reg_bounds_sync(dst_reg);
+			}
+		} else {
+			/* case: R = imm
+			 * remember the value we stored into this reg
+			 */
+			/* clear any state __mark_reg_known doesn't set */
+			mark_reg_unknown(env, regs, insn->dst_reg);
+			regs[insn->dst_reg].type = SCALAR_VALUE;
+			if (BPF_CLASS(insn->code) == BPF_ALU64) {
+				__mark_reg_known(regs + insn->dst_reg,
+						 insn->imm);
+			} else {
+				__mark_reg_known(regs + insn->dst_reg,
+						 (u32)insn->imm);
+			}
+		}
+
+	} else if (opcode > BPF_END) {
+		verbose(env, "invalid BPF_ALU opcode %x\n", opcode);
+		return -EINVAL;
+
+	} else {	/* all other ALU ops: and, sub, xor, add, ... */
+
+		if (BPF_SRC(insn->code) == BPF_X) {
+			if (insn->imm != 0 || insn->off != 0) {
+				verbose(env, "BPF_ALU uses reserved fields\n");
+				return -EINVAL;
+			}
+			/* check src1 operand */
+			err = check_reg_arg(env, insn->src_reg, SRC_OP);
+			if (err)
+				return err;
+		} else {
+			if (insn->src_reg != BPF_REG_0 || insn->off != 0) {
+				verbose(env, "BPF_ALU uses reserved fields\n");
+				return -EINVAL;
+			}
+		}
+
+		/* check src2 operand */
+		err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+		if (err)
+			return err;
+
+		if ((opcode == BPF_MOD || opcode == BPF_DIV) &&
+		    BPF_SRC(insn->code) == BPF_K && insn->imm == 0) {
+			verbose(env, "div by zero\n");
+			return -EINVAL;
+		}
+
+		if ((opcode == BPF_LSH || opcode == BPF_RSH ||
+		     opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) {
+			int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32;
+
+			if (insn->imm < 0 || insn->imm >= size) {
+				verbose(env, "invalid shift %d\n", insn->imm);
+				return -EINVAL;
+			}
+		}
+
+		/* check dest operand */
+		err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
+		if (err)
+			return err;
+
+		return adjust_reg_min_max_vals(env, insn);
+	}
+
+	return 0;
+}
+
+static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
+				   struct bpf_reg_state *dst_reg,
+				   enum bpf_reg_type type,
+				   bool range_right_open)
+{
+	struct bpf_func_state *state;
+	struct bpf_reg_state *reg;
+	int new_range;
+
+	if (dst_reg->off < 0 ||
+	    (dst_reg->off == 0 && range_right_open))
+		/* This doesn't give us any range */
+		return;
+
+	if (dst_reg->umax_value > MAX_PACKET_OFF ||
+	    dst_reg->umax_value + dst_reg->off > MAX_PACKET_OFF)
+		/* Risk of overflow.  For instance, ptr + (1<<63) may be less
+		 * than pkt_end, but that's because it's also less than pkt.
+		 */
+		return;
+
+	new_range = dst_reg->off;
+	if (range_right_open)
+		new_range++;
+
+	/* Examples for register markings:
+	 *
+	 * pkt_data in dst register:
+	 *
+	 *   r2 = r3;
+	 *   r2 += 8;
+	 *   if (r2 > pkt_end) goto <handle exception>
+	 *   <access okay>
+	 *
+	 *   r2 = r3;
+	 *   r2 += 8;
+	 *   if (r2 < pkt_end) goto <access okay>
+	 *   <handle exception>
+	 *
+	 *   Where:
+	 *     r2 == dst_reg, pkt_end == src_reg
+	 *     r2=pkt(id=n,off=8,r=0)
+	 *     r3=pkt(id=n,off=0,r=0)
+	 *
+	 * pkt_data in src register:
+	 *
+	 *   r2 = r3;
+	 *   r2 += 8;
+	 *   if (pkt_end >= r2) goto <access okay>
+	 *   <handle exception>
+	 *
+	 *   r2 = r3;
+	 *   r2 += 8;
+	 *   if (pkt_end <= r2) goto <handle exception>
+	 *   <access okay>
+	 *
+	 *   Where:
+	 *     pkt_end == dst_reg, r2 == src_reg
+	 *     r2=pkt(id=n,off=8,r=0)
+	 *     r3=pkt(id=n,off=0,r=0)
+	 *
+	 * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8)
+	 * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8)
+	 * and [r3, r3 + 8-1) respectively is safe to access depending on
+	 * the check.
+	 */
+
+	/* If our ids match, then we must have the same max_value.  And we
+	 * don't care about the other reg's fixed offset, since if it's too big
+	 * the range won't allow anything.
+	 * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
+	 */
+	bpf_for_each_reg_in_vstate(vstate, state, reg, ({
+		if (reg->type == type && reg->id == dst_reg->id)
+			/* keep the maximum range already checked */
+			reg->range = max(reg->range, new_range);
+	}));
+}
+
+static int is_branch32_taken(struct bpf_reg_state *reg, u32 val, u8 opcode)
+{
+	struct tnum subreg = tnum_subreg(reg->var_off);
+	s32 sval = (s32)val;
+
+	switch (opcode) {
+	case BPF_JEQ:
+		if (tnum_is_const(subreg))
+			return !!tnum_equals_const(subreg, val);
+		break;
+	case BPF_JNE:
+		if (tnum_is_const(subreg))
+			return !tnum_equals_const(subreg, val);
+		break;
+	case BPF_JSET:
+		if ((~subreg.mask & subreg.value) & val)
+			return 1;
+		if (!((subreg.mask | subreg.value) & val))
+			return 0;
+		break;
+	case BPF_JGT:
+		if (reg->u32_min_value > val)
+			return 1;
+		else if (reg->u32_max_value <= val)
+			return 0;
+		break;
+	case BPF_JSGT:
+		if (reg->s32_min_value > sval)
+			return 1;
+		else if (reg->s32_max_value <= sval)
+			return 0;
+		break;
+	case BPF_JLT:
+		if (reg->u32_max_value < val)
+			return 1;
+		else if (reg->u32_min_value >= val)
+			return 0;
+		break;
+	case BPF_JSLT:
+		if (reg->s32_max_value < sval)
+			return 1;
+		else if (reg->s32_min_value >= sval)
+			return 0;
+		break;
+	case BPF_JGE:
+		if (reg->u32_min_value >= val)
+			return 1;
+		else if (reg->u32_max_value < val)
+			return 0;
+		break;
+	case BPF_JSGE:
+		if (reg->s32_min_value >= sval)
+			return 1;
+		else if (reg->s32_max_value < sval)
+			return 0;
+		break;
+	case BPF_JLE:
+		if (reg->u32_max_value <= val)
+			return 1;
+		else if (reg->u32_min_value > val)
+			return 0;
+		break;
+	case BPF_JSLE:
+		if (reg->s32_max_value <= sval)
+			return 1;
+		else if (reg->s32_min_value > sval)
+			return 0;
+		break;
+	}
+
+	return -1;
+}
+
+
+static int is_branch64_taken(struct bpf_reg_state *reg, u64 val, u8 opcode)
+{
+	s64 sval = (s64)val;
+
+	switch (opcode) {
+	case BPF_JEQ:
+		if (tnum_is_const(reg->var_off))
+			return !!tnum_equals_const(reg->var_off, val);
+		break;
+	case BPF_JNE:
+		if (tnum_is_const(reg->var_off))
+			return !tnum_equals_const(reg->var_off, val);
+		break;
+	case BPF_JSET:
+		if ((~reg->var_off.mask & reg->var_off.value) & val)
+			return 1;
+		if (!((reg->var_off.mask | reg->var_off.value) & val))
+			return 0;
+		break;
+	case BPF_JGT:
+		if (reg->umin_value > val)
+			return 1;
+		else if (reg->umax_value <= val)
+			return 0;
+		break;
+	case BPF_JSGT:
+		if (reg->smin_value > sval)
+			return 1;
+		else if (reg->smax_value <= sval)
+			return 0;
+		break;
+	case BPF_JLT:
+		if (reg->umax_value < val)
+			return 1;
+		else if (reg->umin_value >= val)
+			return 0;
+		break;
+	case BPF_JSLT:
+		if (reg->smax_value < sval)
+			return 1;
+		else if (reg->smin_value >= sval)
+			return 0;
+		break;
+	case BPF_JGE:
+		if (reg->umin_value >= val)
+			return 1;
+		else if (reg->umax_value < val)
+			return 0;
+		break;
+	case BPF_JSGE:
+		if (reg->smin_value >= sval)
+			return 1;
+		else if (reg->smax_value < sval)
+			return 0;
+		break;
+	case BPF_JLE:
+		if (reg->umax_value <= val)
+			return 1;
+		else if (reg->umin_value > val)
+			return 0;
+		break;
+	case BPF_JSLE:
+		if (reg->smax_value <= sval)
+			return 1;
+		else if (reg->smin_value > sval)
+			return 0;
+		break;
+	}
+
+	return -1;
+}
+
+/* compute branch direction of the expression "if (reg opcode val) goto target;"
+ * and return:
+ *  1 - branch will be taken and "goto target" will be executed
+ *  0 - branch will not be taken and fall-through to next insn
+ * -1 - unknown. Example: "if (reg < 5)" is unknown when register value
+ *      range [0,10]
+ */
+static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode,
+			   bool is_jmp32)
+{
+	if (__is_pointer_value(false, reg)) {
+		if (!reg_type_not_null(reg->type))
+			return -1;
+
+		/* If pointer is valid tests against zero will fail so we can
+		 * use this to direct branch taken.
+		 */
+		if (val != 0)
+			return -1;
+
+		switch (opcode) {
+		case BPF_JEQ:
+			return 0;
+		case BPF_JNE:
+			return 1;
+		default:
+			return -1;
+		}
+	}
+
+	if (is_jmp32)
+		return is_branch32_taken(reg, val, opcode);
+	return is_branch64_taken(reg, val, opcode);
+}
+
+static int flip_opcode(u32 opcode)
+{
+	/* How can we transform "a <op> b" into "b <op> a"? */
+	static const u8 opcode_flip[16] = {
+		/* these stay the same */
+		[BPF_JEQ  >> 4] = BPF_JEQ,
+		[BPF_JNE  >> 4] = BPF_JNE,
+		[BPF_JSET >> 4] = BPF_JSET,
+		/* these swap "lesser" and "greater" (L and G in the opcodes) */
+		[BPF_JGE  >> 4] = BPF_JLE,
+		[BPF_JGT  >> 4] = BPF_JLT,
+		[BPF_JLE  >> 4] = BPF_JGE,
+		[BPF_JLT  >> 4] = BPF_JGT,
+		[BPF_JSGE >> 4] = BPF_JSLE,
+		[BPF_JSGT >> 4] = BPF_JSLT,
+		[BPF_JSLE >> 4] = BPF_JSGE,
+		[BPF_JSLT >> 4] = BPF_JSGT
+	};
+	return opcode_flip[opcode >> 4];
+}
+
+static int is_pkt_ptr_branch_taken(struct bpf_reg_state *dst_reg,
+				   struct bpf_reg_state *src_reg,
+				   u8 opcode)
+{
+	struct bpf_reg_state *pkt;
+
+	if (src_reg->type == PTR_TO_PACKET_END) {
+		pkt = dst_reg;
+	} else if (dst_reg->type == PTR_TO_PACKET_END) {
+		pkt = src_reg;
+		opcode = flip_opcode(opcode);
+	} else {
+		return -1;
+	}
+
+	if (pkt->range >= 0)
+		return -1;
+
+	switch (opcode) {
+	case BPF_JLE:
+		/* pkt <= pkt_end */
+		fallthrough;
+	case BPF_JGT:
+		/* pkt > pkt_end */
+		if (pkt->range == BEYOND_PKT_END)
+			/* pkt has at last one extra byte beyond pkt_end */
+			return opcode == BPF_JGT;
+		break;
+	case BPF_JLT:
+		/* pkt < pkt_end */
+		fallthrough;
+	case BPF_JGE:
+		/* pkt >= pkt_end */
+		if (pkt->range == BEYOND_PKT_END || pkt->range == AT_PKT_END)
+			return opcode == BPF_JGE;
+		break;
+	}
+	return -1;
+}
+
+/* Adjusts the register min/max values in the case that the dst_reg is the
+ * variable register that we are working on, and src_reg is a constant or we're
+ * simply doing a BPF_K check.
+ * In JEQ/JNE cases we also adjust the var_off values.
+ */
+static void reg_set_min_max(struct bpf_reg_state *true_reg,
+			    struct bpf_reg_state *false_reg,
+			    u64 val, u32 val32,
+			    u8 opcode, bool is_jmp32)
+{
+	struct tnum false_32off = tnum_subreg(false_reg->var_off);
+	struct tnum false_64off = false_reg->var_off;
+	struct tnum true_32off = tnum_subreg(true_reg->var_off);
+	struct tnum true_64off = true_reg->var_off;
+	s64 sval = (s64)val;
+	s32 sval32 = (s32)val32;
+
+	/* If the dst_reg is a pointer, we can't learn anything about its
+	 * variable offset from the compare (unless src_reg were a pointer into
+	 * the same object, but we don't bother with that.
+	 * Since false_reg and true_reg have the same type by construction, we
+	 * only need to check one of them for pointerness.
+	 */
+	if (__is_pointer_value(false, false_reg))
+		return;
+
+	switch (opcode) {
+	/* JEQ/JNE comparison doesn't change the register equivalence.
+	 *
+	 * r1 = r2;
+	 * if (r1 == 42) goto label;
+	 * ...
+	 * label: // here both r1 and r2 are known to be 42.
+	 *
+	 * Hence when marking register as known preserve it's ID.
+	 */
+	case BPF_JEQ:
+		if (is_jmp32) {
+			__mark_reg32_known(true_reg, val32);
+			true_32off = tnum_subreg(true_reg->var_off);
+		} else {
+			___mark_reg_known(true_reg, val);
+			true_64off = true_reg->var_off;
+		}
+		break;
+	case BPF_JNE:
+		if (is_jmp32) {
+			__mark_reg32_known(false_reg, val32);
+			false_32off = tnum_subreg(false_reg->var_off);
+		} else {
+			___mark_reg_known(false_reg, val);
+			false_64off = false_reg->var_off;
+		}
+		break;
+	case BPF_JSET:
+		if (is_jmp32) {
+			false_32off = tnum_and(false_32off, tnum_const(~val32));
+			if (is_power_of_2(val32))
+				true_32off = tnum_or(true_32off,
+						     tnum_const(val32));
+		} else {
+			false_64off = tnum_and(false_64off, tnum_const(~val));
+			if (is_power_of_2(val))
+				true_64off = tnum_or(true_64off,
+						     tnum_const(val));
+		}
+		break;
+	case BPF_JGE:
+	case BPF_JGT:
+	{
+		if (is_jmp32) {
+			u32 false_umax = opcode == BPF_JGT ? val32  : val32 - 1;
+			u32 true_umin = opcode == BPF_JGT ? val32 + 1 : val32;
+
+			false_reg->u32_max_value = min(false_reg->u32_max_value,
+						       false_umax);
+			true_reg->u32_min_value = max(true_reg->u32_min_value,
+						      true_umin);
+		} else {
+			u64 false_umax = opcode == BPF_JGT ? val    : val - 1;
+			u64 true_umin = opcode == BPF_JGT ? val + 1 : val;
+
+			false_reg->umax_value = min(false_reg->umax_value, false_umax);
+			true_reg->umin_value = max(true_reg->umin_value, true_umin);
+		}
+		break;
+	}
+	case BPF_JSGE:
+	case BPF_JSGT:
+	{
+		if (is_jmp32) {
+			s32 false_smax = opcode == BPF_JSGT ? sval32    : sval32 - 1;
+			s32 true_smin = opcode == BPF_JSGT ? sval32 + 1 : sval32;
+
+			false_reg->s32_max_value = min(false_reg->s32_max_value, false_smax);
+			true_reg->s32_min_value = max(true_reg->s32_min_value, true_smin);
+		} else {
+			s64 false_smax = opcode == BPF_JSGT ? sval    : sval - 1;
+			s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval;
+
+			false_reg->smax_value = min(false_reg->smax_value, false_smax);
+			true_reg->smin_value = max(true_reg->smin_value, true_smin);
+		}
+		break;
+	}
+	case BPF_JLE:
+	case BPF_JLT:
+	{
+		if (is_jmp32) {
+			u32 false_umin = opcode == BPF_JLT ? val32  : val32 + 1;
+			u32 true_umax = opcode == BPF_JLT ? val32 - 1 : val32;
+
+			false_reg->u32_min_value = max(false_reg->u32_min_value,
+						       false_umin);
+			true_reg->u32_max_value = min(true_reg->u32_max_value,
+						      true_umax);
+		} else {
+			u64 false_umin = opcode == BPF_JLT ? val    : val + 1;
+			u64 true_umax = opcode == BPF_JLT ? val - 1 : val;
+
+			false_reg->umin_value = max(false_reg->umin_value, false_umin);
+			true_reg->umax_value = min(true_reg->umax_value, true_umax);
+		}
+		break;
+	}
+	case BPF_JSLE:
+	case BPF_JSLT:
+	{
+		if (is_jmp32) {
+			s32 false_smin = opcode == BPF_JSLT ? sval32    : sval32 + 1;
+			s32 true_smax = opcode == BPF_JSLT ? sval32 - 1 : sval32;
+
+			false_reg->s32_min_value = max(false_reg->s32_min_value, false_smin);
+			true_reg->s32_max_value = min(true_reg->s32_max_value, true_smax);
+		} else {
+			s64 false_smin = opcode == BPF_JSLT ? sval    : sval + 1;
+			s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval;
+
+			false_reg->smin_value = max(false_reg->smin_value, false_smin);
+			true_reg->smax_value = min(true_reg->smax_value, true_smax);
+		}
+		break;
+	}
+	default:
+		return;
+	}
+
+	if (is_jmp32) {
+		false_reg->var_off = tnum_or(tnum_clear_subreg(false_64off),
+					     tnum_subreg(false_32off));
+		true_reg->var_off = tnum_or(tnum_clear_subreg(true_64off),
+					    tnum_subreg(true_32off));
+		__reg_combine_32_into_64(false_reg);
+		__reg_combine_32_into_64(true_reg);
+	} else {
+		false_reg->var_off = false_64off;
+		true_reg->var_off = true_64off;
+		__reg_combine_64_into_32(false_reg);
+		__reg_combine_64_into_32(true_reg);
+	}
+}
+
+/* Same as above, but for the case that dst_reg holds a constant and src_reg is
+ * the variable reg.
+ */
+static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
+				struct bpf_reg_state *false_reg,
+				u64 val, u32 val32,
+				u8 opcode, bool is_jmp32)
+{
+	opcode = flip_opcode(opcode);
+	/* This uses zero as "not present in table"; luckily the zero opcode,
+	 * BPF_JA, can't get here.
+	 */
+	if (opcode)
+		reg_set_min_max(true_reg, false_reg, val, val32, opcode, is_jmp32);
+}
+
+/* Regs are known to be equal, so intersect their min/max/var_off */
+static void __reg_combine_min_max(struct bpf_reg_state *src_reg,
+				  struct bpf_reg_state *dst_reg)
+{
+	src_reg->umin_value = dst_reg->umin_value = max(src_reg->umin_value,
+							dst_reg->umin_value);
+	src_reg->umax_value = dst_reg->umax_value = min(src_reg->umax_value,
+							dst_reg->umax_value);
+	src_reg->smin_value = dst_reg->smin_value = max(src_reg->smin_value,
+							dst_reg->smin_value);
+	src_reg->smax_value = dst_reg->smax_value = min(src_reg->smax_value,
+							dst_reg->smax_value);
+	src_reg->var_off = dst_reg->var_off = tnum_intersect(src_reg->var_off,
+							     dst_reg->var_off);
+	reg_bounds_sync(src_reg);
+	reg_bounds_sync(dst_reg);
+}
+
+static void reg_combine_min_max(struct bpf_reg_state *true_src,
+				struct bpf_reg_state *true_dst,
+				struct bpf_reg_state *false_src,
+				struct bpf_reg_state *false_dst,
+				u8 opcode)
+{
+	switch (opcode) {
+	case BPF_JEQ:
+		__reg_combine_min_max(true_src, true_dst);
+		break;
+	case BPF_JNE:
+		__reg_combine_min_max(false_src, false_dst);
+		break;
+	}
+}
+
+static void mark_ptr_or_null_reg(struct bpf_func_state *state,
+				 struct bpf_reg_state *reg, u32 id,
+				 bool is_null)
+{
+	if (type_may_be_null(reg->type) && reg->id == id &&
+	    !WARN_ON_ONCE(!reg->id)) {
+		if (WARN_ON_ONCE(reg->smin_value || reg->smax_value ||
+				 !tnum_equals_const(reg->var_off, 0) ||
+				 reg->off)) {
+			/* Old offset (both fixed and variable parts) should
+			 * have been known-zero, because we don't allow pointer
+			 * arithmetic on pointers that might be NULL. If we
+			 * see this happening, don't convert the register.
+			 */
+			return;
+		}
+		if (is_null) {
+			reg->type = SCALAR_VALUE;
+			/* We don't need id and ref_obj_id from this point
+			 * onwards anymore, thus we should better reset it,
+			 * so that state pruning has chances to take effect.
+			 */
+			reg->id = 0;
+			reg->ref_obj_id = 0;
+
+			return;
+		}
+
+		mark_ptr_not_null_reg(reg);
+
+		if (!reg_may_point_to_spin_lock(reg)) {
+			/* For not-NULL ptr, reg->ref_obj_id will be reset
+			 * in release_reference().
+			 *
+			 * reg->id is still used by spin_lock ptr. Other
+			 * than spin_lock ptr type, reg->id can be reset.
+			 */
+			reg->id = 0;
+		}
+	}
+}
+
+/* The logic is similar to find_good_pkt_pointers(), both could eventually
+ * be folded together at some point.
+ */
+static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno,
+				  bool is_null)
+{
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_reg_state *regs = state->regs, *reg;
+	u32 ref_obj_id = regs[regno].ref_obj_id;
+	u32 id = regs[regno].id;
+
+	if (ref_obj_id && ref_obj_id == id && is_null)
+		/* regs[regno] is in the " == NULL" branch.
+		 * No one could have freed the reference state before
+		 * doing the NULL check.
+		 */
+		WARN_ON_ONCE(release_reference_state(state, id));
+
+	bpf_for_each_reg_in_vstate(vstate, state, reg, ({
+		mark_ptr_or_null_reg(state, reg, id, is_null);
+	}));
+}
+
+static bool try_match_pkt_pointers(const struct bpf_insn *insn,
+				   struct bpf_reg_state *dst_reg,
+				   struct bpf_reg_state *src_reg,
+				   struct bpf_verifier_state *this_branch,
+				   struct bpf_verifier_state *other_branch)
+{
+	if (BPF_SRC(insn->code) != BPF_X)
+		return false;
+
+	/* Pointers are always 64-bit. */
+	if (BPF_CLASS(insn->code) == BPF_JMP32)
+		return false;
+
+	switch (BPF_OP(insn->code)) {
+	case BPF_JGT:
+		if ((dst_reg->type == PTR_TO_PACKET &&
+		     src_reg->type == PTR_TO_PACKET_END) ||
+		    (dst_reg->type == PTR_TO_PACKET_META &&
+		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
+			/* pkt_data' > pkt_end, pkt_meta' > pkt_data */
+			find_good_pkt_pointers(this_branch, dst_reg,
+					       dst_reg->type, false);
+			mark_pkt_end(other_branch, insn->dst_reg, true);
+		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
+			    src_reg->type == PTR_TO_PACKET) ||
+			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+			    src_reg->type == PTR_TO_PACKET_META)) {
+			/* pkt_end > pkt_data', pkt_data > pkt_meta' */
+			find_good_pkt_pointers(other_branch, src_reg,
+					       src_reg->type, true);
+			mark_pkt_end(this_branch, insn->src_reg, false);
+		} else {
+			return false;
+		}
+		break;
+	case BPF_JLT:
+		if ((dst_reg->type == PTR_TO_PACKET &&
+		     src_reg->type == PTR_TO_PACKET_END) ||
+		    (dst_reg->type == PTR_TO_PACKET_META &&
+		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
+			/* pkt_data' < pkt_end, pkt_meta' < pkt_data */
+			find_good_pkt_pointers(other_branch, dst_reg,
+					       dst_reg->type, true);
+			mark_pkt_end(this_branch, insn->dst_reg, false);
+		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
+			    src_reg->type == PTR_TO_PACKET) ||
+			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+			    src_reg->type == PTR_TO_PACKET_META)) {
+			/* pkt_end < pkt_data', pkt_data > pkt_meta' */
+			find_good_pkt_pointers(this_branch, src_reg,
+					       src_reg->type, false);
+			mark_pkt_end(other_branch, insn->src_reg, true);
+		} else {
+			return false;
+		}
+		break;
+	case BPF_JGE:
+		if ((dst_reg->type == PTR_TO_PACKET &&
+		     src_reg->type == PTR_TO_PACKET_END) ||
+		    (dst_reg->type == PTR_TO_PACKET_META &&
+		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
+			/* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */
+			find_good_pkt_pointers(this_branch, dst_reg,
+					       dst_reg->type, true);
+			mark_pkt_end(other_branch, insn->dst_reg, false);
+		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
+			    src_reg->type == PTR_TO_PACKET) ||
+			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+			    src_reg->type == PTR_TO_PACKET_META)) {
+			/* pkt_end >= pkt_data', pkt_data >= pkt_meta' */
+			find_good_pkt_pointers(other_branch, src_reg,
+					       src_reg->type, false);
+			mark_pkt_end(this_branch, insn->src_reg, true);
+		} else {
+			return false;
+		}
+		break;
+	case BPF_JLE:
+		if ((dst_reg->type == PTR_TO_PACKET &&
+		     src_reg->type == PTR_TO_PACKET_END) ||
+		    (dst_reg->type == PTR_TO_PACKET_META &&
+		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
+			/* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */
+			find_good_pkt_pointers(other_branch, dst_reg,
+					       dst_reg->type, false);
+			mark_pkt_end(this_branch, insn->dst_reg, true);
+		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
+			    src_reg->type == PTR_TO_PACKET) ||
+			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+			    src_reg->type == PTR_TO_PACKET_META)) {
+			/* pkt_end <= pkt_data', pkt_data <= pkt_meta' */
+			find_good_pkt_pointers(this_branch, src_reg,
+					       src_reg->type, true);
+			mark_pkt_end(other_branch, insn->src_reg, false);
+		} else {
+			return false;
+		}
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static void find_equal_scalars(struct bpf_verifier_state *vstate,
+			       struct bpf_reg_state *known_reg)
+{
+	struct bpf_func_state *state;
+	struct bpf_reg_state *reg;
+
+	bpf_for_each_reg_in_vstate(vstate, state, reg, ({
+		if (reg->type == SCALAR_VALUE && reg->id == known_reg->id)
+			copy_register_state(reg, known_reg);
+	}));
+}
+
+static int check_cond_jmp_op(struct bpf_verifier_env *env,
+			     struct bpf_insn *insn, int *insn_idx)
+{
+	struct bpf_verifier_state *this_branch = env->cur_state;
+	struct bpf_verifier_state *other_branch;
+	struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs;
+	struct bpf_reg_state *dst_reg, *other_branch_regs, *src_reg = NULL;
+	u8 opcode = BPF_OP(insn->code);
+	bool is_jmp32;
+	int pred = -1;
+	int err;
+
+	/* Only conditional jumps are expected to reach here. */
+	if (opcode == BPF_JA || opcode > BPF_JSLE) {
+		verbose(env, "invalid BPF_JMP/JMP32 opcode %x\n", opcode);
+		return -EINVAL;
+	}
+
+	/* check src2 operand */
+	err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+	if (err)
+		return err;
+
+	dst_reg = &regs[insn->dst_reg];
+	if (BPF_SRC(insn->code) == BPF_X) {
+		if (insn->imm != 0) {
+			verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
+			return -EINVAL;
+		}
+
+		/* check src1 operand */
+		err = check_reg_arg(env, insn->src_reg, SRC_OP);
+		if (err)
+			return err;
+
+		src_reg = &regs[insn->src_reg];
+		if (!(reg_is_pkt_pointer_any(dst_reg) && reg_is_pkt_pointer_any(src_reg)) &&
+		    is_pointer_value(env, insn->src_reg)) {
+			verbose(env, "R%d pointer comparison prohibited\n",
+				insn->src_reg);
+			return -EACCES;
+		}
+	} else {
+		if (insn->src_reg != BPF_REG_0) {
+			verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
+			return -EINVAL;
+		}
+	}
+
+	is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
+
+	if (BPF_SRC(insn->code) == BPF_K) {
+		pred = is_branch_taken(dst_reg, insn->imm, opcode, is_jmp32);
+	} else if (src_reg->type == SCALAR_VALUE &&
+		   is_jmp32 && tnum_is_const(tnum_subreg(src_reg->var_off))) {
+		pred = is_branch_taken(dst_reg,
+				       tnum_subreg(src_reg->var_off).value,
+				       opcode,
+				       is_jmp32);
+	} else if (src_reg->type == SCALAR_VALUE &&
+		   !is_jmp32 && tnum_is_const(src_reg->var_off)) {
+		pred = is_branch_taken(dst_reg,
+				       src_reg->var_off.value,
+				       opcode,
+				       is_jmp32);
+	} else if (reg_is_pkt_pointer_any(dst_reg) &&
+		   reg_is_pkt_pointer_any(src_reg) &&
+		   !is_jmp32) {
+		pred = is_pkt_ptr_branch_taken(dst_reg, src_reg, opcode);
+	}
+
+	if (pred >= 0) {
+		/* If we get here with a dst_reg pointer type it is because
+		 * above is_branch_taken() special cased the 0 comparison.
+		 */
+		if (!__is_pointer_value(false, dst_reg))
+			err = mark_chain_precision(env, insn->dst_reg);
+		if (BPF_SRC(insn->code) == BPF_X && !err &&
+		    !__is_pointer_value(false, src_reg))
+			err = mark_chain_precision(env, insn->src_reg);
+		if (err)
+			return err;
+	}
+
+	if (pred == 1) {
+		/* Only follow the goto, ignore fall-through. If needed, push
+		 * the fall-through branch for simulation under speculative
+		 * execution.
+		 */
+		if (!env->bypass_spec_v1 &&
+		    !sanitize_speculative_path(env, insn, *insn_idx + 1,
+					       *insn_idx))
+			return -EFAULT;
+		if (env->log.level & BPF_LOG_LEVEL)
+			print_insn_state(env, this_branch->frame[this_branch->curframe]);
+		*insn_idx += insn->off;
+		return 0;
+	} else if (pred == 0) {
+		/* Only follow the fall-through branch, since that's where the
+		 * program will go. If needed, push the goto branch for
+		 * simulation under speculative execution.
+		 */
+		if (!env->bypass_spec_v1 &&
+		    !sanitize_speculative_path(env, insn,
+					       *insn_idx + insn->off + 1,
+					       *insn_idx))
+			return -EFAULT;
+		if (env->log.level & BPF_LOG_LEVEL)
+			print_insn_state(env, this_branch->frame[this_branch->curframe]);
+		return 0;
+	}
+
+	other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx,
+				  false);
+	if (!other_branch)
+		return -EFAULT;
+	other_branch_regs = other_branch->frame[other_branch->curframe]->regs;
+
+	/* detect if we are comparing against a constant value so we can adjust
+	 * our min/max values for our dst register.
+	 * this is only legit if both are scalars (or pointers to the same
+	 * object, I suppose, but we don't support that right now), because
+	 * otherwise the different base pointers mean the offsets aren't
+	 * comparable.
+	 */
+	if (BPF_SRC(insn->code) == BPF_X) {
+		struct bpf_reg_state *src_reg = &regs[insn->src_reg];
+
+		if (dst_reg->type == SCALAR_VALUE &&
+		    src_reg->type == SCALAR_VALUE) {
+			if (tnum_is_const(src_reg->var_off) ||
+			    (is_jmp32 &&
+			     tnum_is_const(tnum_subreg(src_reg->var_off))))
+				reg_set_min_max(&other_branch_regs[insn->dst_reg],
+						dst_reg,
+						src_reg->var_off.value,
+						tnum_subreg(src_reg->var_off).value,
+						opcode, is_jmp32);
+			else if (tnum_is_const(dst_reg->var_off) ||
+				 (is_jmp32 &&
+				  tnum_is_const(tnum_subreg(dst_reg->var_off))))
+				reg_set_min_max_inv(&other_branch_regs[insn->src_reg],
+						    src_reg,
+						    dst_reg->var_off.value,
+						    tnum_subreg(dst_reg->var_off).value,
+						    opcode, is_jmp32);
+			else if (!is_jmp32 &&
+				 (opcode == BPF_JEQ || opcode == BPF_JNE))
+				/* Comparing for equality, we can combine knowledge */
+				reg_combine_min_max(&other_branch_regs[insn->src_reg],
+						    &other_branch_regs[insn->dst_reg],
+						    src_reg, dst_reg, opcode);
+			if (src_reg->id &&
+			    !WARN_ON_ONCE(src_reg->id != other_branch_regs[insn->src_reg].id)) {
+				find_equal_scalars(this_branch, src_reg);
+				find_equal_scalars(other_branch, &other_branch_regs[insn->src_reg]);
+			}
+
+		}
+	} else if (dst_reg->type == SCALAR_VALUE) {
+		reg_set_min_max(&other_branch_regs[insn->dst_reg],
+					dst_reg, insn->imm, (u32)insn->imm,
+					opcode, is_jmp32);
+	}
+
+	if (dst_reg->type == SCALAR_VALUE && dst_reg->id &&
+	    !WARN_ON_ONCE(dst_reg->id != other_branch_regs[insn->dst_reg].id)) {
+		find_equal_scalars(this_branch, dst_reg);
+		find_equal_scalars(other_branch, &other_branch_regs[insn->dst_reg]);
+	}
+
+	/* detect if R == 0 where R is returned from bpf_map_lookup_elem().
+	 * NOTE: these optimizations below are related with pointer comparison
+	 *       which will never be JMP32.
+	 */
+	if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K &&
+	    insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) &&
+	    type_may_be_null(dst_reg->type)) {
+		/* Mark all identical registers in each branch as either
+		 * safe or unknown depending R == 0 or R != 0 conditional.
+		 */
+		mark_ptr_or_null_regs(this_branch, insn->dst_reg,
+				      opcode == BPF_JNE);
+		mark_ptr_or_null_regs(other_branch, insn->dst_reg,
+				      opcode == BPF_JEQ);
+	} else if (!try_match_pkt_pointers(insn, dst_reg, &regs[insn->src_reg],
+					   this_branch, other_branch) &&
+		   is_pointer_value(env, insn->dst_reg)) {
+		verbose(env, "R%d pointer comparison prohibited\n",
+			insn->dst_reg);
+		return -EACCES;
+	}
+	if (env->log.level & BPF_LOG_LEVEL)
+		print_insn_state(env, this_branch->frame[this_branch->curframe]);
+	return 0;
+}
+
+/* verify BPF_LD_IMM64 instruction */
+static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+	struct bpf_insn_aux_data *aux = cur_aux(env);
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *dst_reg;
+	struct bpf_map *map;
+	int err;
+
+	if (BPF_SIZE(insn->code) != BPF_DW) {
+		verbose(env, "invalid BPF_LD_IMM insn\n");
+		return -EINVAL;
+	}
+	if (insn->off != 0) {
+		verbose(env, "BPF_LD_IMM64 uses reserved fields\n");
+		return -EINVAL;
+	}
+
+	err = check_reg_arg(env, insn->dst_reg, DST_OP);
+	if (err)
+		return err;
+
+	dst_reg = &regs[insn->dst_reg];
+	if (insn->src_reg == 0) {
+		u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
+
+		dst_reg->type = SCALAR_VALUE;
+		__mark_reg_known(&regs[insn->dst_reg], imm);
+		return 0;
+	}
+
+	/* All special src_reg cases are listed below. From this point onwards
+	 * we either succeed and assign a corresponding dst_reg->type after
+	 * zeroing the offset, or fail and reject the program.
+	 */
+	mark_reg_known_zero(env, regs, insn->dst_reg);
+
+	if (insn->src_reg == BPF_PSEUDO_BTF_ID) {
+		dst_reg->type = aux->btf_var.reg_type;
+		switch (base_type(dst_reg->type)) {
+		case PTR_TO_MEM:
+			dst_reg->mem_size = aux->btf_var.mem_size;
+			break;
+		case PTR_TO_BTF_ID:
+			dst_reg->btf = aux->btf_var.btf;
+			dst_reg->btf_id = aux->btf_var.btf_id;
+			break;
+		default:
+			verbose(env, "bpf verifier is misconfigured\n");
+			return -EFAULT;
+		}
+		return 0;
+	}
+
+	if (insn->src_reg == BPF_PSEUDO_FUNC) {
+		struct bpf_prog_aux *aux = env->prog->aux;
+		u32 subprogno = find_subprog(env,
+					     env->insn_idx + insn->imm + 1);
+
+		if (!aux->func_info) {
+			verbose(env, "missing btf func_info\n");
+			return -EINVAL;
+		}
+		if (aux->func_info_aux[subprogno].linkage != BTF_FUNC_STATIC) {
+			verbose(env, "callback function not static\n");
+			return -EINVAL;
+		}
+
+		dst_reg->type = PTR_TO_FUNC;
+		dst_reg->subprogno = subprogno;
+		return 0;
+	}
+
+	map = env->used_maps[aux->map_index];
+	dst_reg->map_ptr = map;
+
+	if (insn->src_reg == BPF_PSEUDO_MAP_VALUE ||
+	    insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE) {
+		dst_reg->type = PTR_TO_MAP_VALUE;
+		dst_reg->off = aux->map_off;
+		if (map_value_has_spin_lock(map))
+			dst_reg->id = ++env->id_gen;
+	} else if (insn->src_reg == BPF_PSEUDO_MAP_FD ||
+		   insn->src_reg == BPF_PSEUDO_MAP_IDX) {
+		dst_reg->type = CONST_PTR_TO_MAP;
+	} else {
+		verbose(env, "bpf verifier is misconfigured\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static bool may_access_skb(enum bpf_prog_type type)
+{
+	switch (type) {
+	case BPF_PROG_TYPE_SOCKET_FILTER:
+	case BPF_PROG_TYPE_SCHED_CLS:
+	case BPF_PROG_TYPE_SCHED_ACT:
+		return true;
+	default:
+		return false;
+	}
+}
+
+/* verify safety of LD_ABS|LD_IND instructions:
+ * - they can only appear in the programs where ctx == skb
+ * - since they are wrappers of function calls, they scratch R1-R5 registers,
+ *   preserve R6-R9, and store return value into R0
+ *
+ * Implicit input:
+ *   ctx == skb == R6 == CTX
+ *
+ * Explicit input:
+ *   SRC == any register
+ *   IMM == 32-bit immediate
+ *
+ * Output:
+ *   R0 - 8/16/32-bit skb data converted to cpu endianness
+ */
+static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	static const int ctx_reg = BPF_REG_6;
+	u8 mode = BPF_MODE(insn->code);
+	int i, err;
+
+	if (!may_access_skb(resolve_prog_type(env->prog))) {
+		verbose(env, "BPF_LD_[ABS|IND] instructions not allowed for this program type\n");
+		return -EINVAL;
+	}
+
+	if (!env->ops->gen_ld_abs) {
+		verbose(env, "bpf verifier is misconfigured\n");
+		return -EINVAL;
+	}
+
+	if (insn->dst_reg != BPF_REG_0 || insn->off != 0 ||
+	    BPF_SIZE(insn->code) == BPF_DW ||
+	    (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) {
+		verbose(env, "BPF_LD_[ABS|IND] uses reserved fields\n");
+		return -EINVAL;
+	}
+
+	/* check whether implicit source operand (register R6) is readable */
+	err = check_reg_arg(env, ctx_reg, SRC_OP);
+	if (err)
+		return err;
+
+	/* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as
+	 * gen_ld_abs() may terminate the program at runtime, leading to
+	 * reference leak.
+	 */
+	err = check_reference_leak(env);
+	if (err) {
+		verbose(env, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n");
+		return err;
+	}
+
+	if (env->cur_state->active_spin_lock) {
+		verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n");
+		return -EINVAL;
+	}
+
+	if (regs[ctx_reg].type != PTR_TO_CTX) {
+		verbose(env,
+			"at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
+		return -EINVAL;
+	}
+
+	if (mode == BPF_IND) {
+		/* check explicit source operand */
+		err = check_reg_arg(env, insn->src_reg, SRC_OP);
+		if (err)
+			return err;
+	}
+
+	err = check_ptr_off_reg(env, &regs[ctx_reg], ctx_reg);
+	if (err < 0)
+		return err;
+
+	/* reset caller saved regs to unreadable */
+	for (i = 0; i < CALLER_SAVED_REGS; i++) {
+		mark_reg_not_init(env, regs, caller_saved[i]);
+		check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+	}
+
+	/* mark destination R0 register as readable, since it contains
+	 * the value fetched from the packet.
+	 * Already marked as written above.
+	 */
+	mark_reg_unknown(env, regs, BPF_REG_0);
+	/* ld_abs load up to 32-bit skb data. */
+	regs[BPF_REG_0].subreg_def = env->insn_idx + 1;
+	return 0;
+}
+
+static int check_return_code(struct bpf_verifier_env *env)
+{
+	struct tnum enforce_attach_type_range = tnum_unknown;
+	const struct bpf_prog *prog = env->prog;
+	struct bpf_reg_state *reg;
+	struct tnum range = tnum_range(0, 1), const_0 = tnum_const(0);
+	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
+	int err;
+	struct bpf_func_state *frame = env->cur_state->frame[0];
+	const bool is_subprog = frame->subprogno;
+
+	/* LSM and struct_ops func-ptr's return type could be "void" */
+	if (!is_subprog) {
+		switch (prog_type) {
+		case BPF_PROG_TYPE_LSM:
+			if (prog->expected_attach_type == BPF_LSM_CGROUP)
+				/* See below, can be 0 or 0-1 depending on hook. */
+				break;
+			fallthrough;
+		case BPF_PROG_TYPE_STRUCT_OPS:
+			if (!prog->aux->attach_func_proto->type)
+				return 0;
+			break;
+		default:
+			break;
+		}
+	}
+
+	/* eBPF calling convention is such that R0 is used
+	 * to return the value from eBPF program.
+	 * Make sure that it's readable at this time
+	 * of bpf_exit, which means that program wrote
+	 * something into it earlier
+	 */
+	err = check_reg_arg(env, BPF_REG_0, SRC_OP);
+	if (err)
+		return err;
+
+	if (is_pointer_value(env, BPF_REG_0)) {
+		verbose(env, "R0 leaks addr as return value\n");
+		return -EACCES;
+	}
+
+	reg = cur_regs(env) + BPF_REG_0;
+
+	if (frame->in_async_callback_fn) {
+		/* enforce return zero from async callbacks like timer */
+		if (reg->type != SCALAR_VALUE) {
+			verbose(env, "In async callback the register R0 is not a known value (%s)\n",
+				reg_type_str(env, reg->type));
+			return -EINVAL;
+		}
+
+		if (!tnum_in(const_0, reg->var_off)) {
+			verbose_invalid_scalar(env, reg, &const_0, "async callback", "R0");
+			return -EINVAL;
+		}
+		return 0;
+	}
+
+	if (is_subprog) {
+		if (reg->type != SCALAR_VALUE) {
+			verbose(env, "At subprogram exit the register R0 is not a scalar value (%s)\n",
+				reg_type_str(env, reg->type));
+			return -EINVAL;
+		}
+		return 0;
+	}
+
+	switch (prog_type) {
+	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+		if (env->prog->expected_attach_type == BPF_CGROUP_UDP4_RECVMSG ||
+		    env->prog->expected_attach_type == BPF_CGROUP_UDP6_RECVMSG ||
+		    env->prog->expected_attach_type == BPF_CGROUP_INET4_GETPEERNAME ||
+		    env->prog->expected_attach_type == BPF_CGROUP_INET6_GETPEERNAME ||
+		    env->prog->expected_attach_type == BPF_CGROUP_INET4_GETSOCKNAME ||
+		    env->prog->expected_attach_type == BPF_CGROUP_INET6_GETSOCKNAME)
+			range = tnum_range(1, 1);
+		if (env->prog->expected_attach_type == BPF_CGROUP_INET4_BIND ||
+		    env->prog->expected_attach_type == BPF_CGROUP_INET6_BIND)
+			range = tnum_range(0, 3);
+		break;
+	case BPF_PROG_TYPE_CGROUP_SKB:
+		if (env->prog->expected_attach_type == BPF_CGROUP_INET_EGRESS) {
+			range = tnum_range(0, 3);
+			enforce_attach_type_range = tnum_range(2, 3);
+		}
+		break;
+	case BPF_PROG_TYPE_CGROUP_SOCK:
+	case BPF_PROG_TYPE_SOCK_OPS:
+	case BPF_PROG_TYPE_CGROUP_DEVICE:
+	case BPF_PROG_TYPE_CGROUP_SYSCTL:
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+		break;
+	case BPF_PROG_TYPE_RAW_TRACEPOINT:
+		if (!env->prog->aux->attach_btf_id)
+			return 0;
+		range = tnum_const(0);
+		break;
+	case BPF_PROG_TYPE_TRACING:
+		switch (env->prog->expected_attach_type) {
+		case BPF_TRACE_FENTRY:
+		case BPF_TRACE_FEXIT:
+			range = tnum_const(0);
+			break;
+		case BPF_TRACE_RAW_TP:
+		case BPF_MODIFY_RETURN:
+			return 0;
+		case BPF_TRACE_ITER:
+			break;
+		default:
+			return -ENOTSUPP;
+		}
+		break;
+	case BPF_PROG_TYPE_SK_LOOKUP:
+		range = tnum_range(SK_DROP, SK_PASS);
+		break;
+
+	case BPF_PROG_TYPE_LSM:
+		if (env->prog->expected_attach_type != BPF_LSM_CGROUP) {
+			/* Regular BPF_PROG_TYPE_LSM programs can return
+			 * any value.
+			 */
+			return 0;
+		}
+		if (!env->prog->aux->attach_func_proto->type) {
+			/* Make sure programs that attach to void
+			 * hooks don't try to modify return value.
+			 */
+			range = tnum_range(1, 1);
+		}
+		break;
+
+	case BPF_PROG_TYPE_EXT:
+		/* freplace program can return anything as its return value
+		 * depends on the to-be-replaced kernel func or bpf program.
+		 */
+	default:
+		return 0;
+	}
+
+	if (reg->type != SCALAR_VALUE) {
+		verbose(env, "At program exit the register R0 is not a known value (%s)\n",
+			reg_type_str(env, reg->type));
+		return -EINVAL;
+	}
+
+	if (!tnum_in(range, reg->var_off)) {
+		verbose_invalid_scalar(env, reg, &range, "program exit", "R0");
+		if (prog->expected_attach_type == BPF_LSM_CGROUP &&
+		    prog_type == BPF_PROG_TYPE_LSM &&
+		    !prog->aux->attach_func_proto->type)
+			verbose(env, "Note, BPF_LSM_CGROUP that attach to void LSM hooks can't modify return value!\n");
+		return -EINVAL;
+	}
+
+	if (!tnum_is_unknown(enforce_attach_type_range) &&
+	    tnum_in(enforce_attach_type_range, reg->var_off))
+		env->prog->enforce_expected_attach_type = 1;
+	return 0;
+}
+
+/* non-recursive DFS pseudo code
+ * 1  procedure DFS-iterative(G,v):
+ * 2      label v as discovered
+ * 3      let S be a stack
+ * 4      S.push(v)
+ * 5      while S is not empty
+ * 6            t <- S.pop()
+ * 7            if t is what we're looking for:
+ * 8                return t
+ * 9            for all edges e in G.adjacentEdges(t) do
+ * 10               if edge e is already labelled
+ * 11                   continue with the next edge
+ * 12               w <- G.adjacentVertex(t,e)
+ * 13               if vertex w is not discovered and not explored
+ * 14                   label e as tree-edge
+ * 15                   label w as discovered
+ * 16                   S.push(w)
+ * 17                   continue at 5
+ * 18               else if vertex w is discovered
+ * 19                   label e as back-edge
+ * 20               else
+ * 21                   // vertex w is explored
+ * 22                   label e as forward- or cross-edge
+ * 23           label t as explored
+ * 24           S.pop()
+ *
+ * convention:
+ * 0x10 - discovered
+ * 0x11 - discovered and fall-through edge labelled
+ * 0x12 - discovered and fall-through and branch edges labelled
+ * 0x20 - explored
+ */
+
+enum {
+	DISCOVERED = 0x10,
+	EXPLORED = 0x20,
+	FALLTHROUGH = 1,
+	BRANCH = 2,
+};
+
+static u32 state_htab_size(struct bpf_verifier_env *env)
+{
+	return env->prog->len;
+}
+
+static struct bpf_verifier_state_list **explored_state(
+					struct bpf_verifier_env *env,
+					int idx)
+{
+	struct bpf_verifier_state *cur = env->cur_state;
+	struct bpf_func_state *state = cur->frame[cur->curframe];
+
+	return &env->explored_states[(idx ^ state->callsite) % state_htab_size(env)];
+}
+
+static void mark_prune_point(struct bpf_verifier_env *env, int idx)
+{
+	env->insn_aux_data[idx].prune_point = true;
+}
+
+static bool is_prune_point(struct bpf_verifier_env *env, int insn_idx)
+{
+	return env->insn_aux_data[insn_idx].prune_point;
+}
+
+enum {
+	DONE_EXPLORING = 0,
+	KEEP_EXPLORING = 1,
+};
+
+/* t, w, e - match pseudo-code above:
+ * t - index of current instruction
+ * w - next instruction
+ * e - edge
+ */
+static int push_insn(int t, int w, int e, struct bpf_verifier_env *env,
+		     bool loop_ok)
+{
+	int *insn_stack = env->cfg.insn_stack;
+	int *insn_state = env->cfg.insn_state;
+
+	if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH))
+		return DONE_EXPLORING;
+
+	if (e == BRANCH && insn_state[t] >= (DISCOVERED | BRANCH))
+		return DONE_EXPLORING;
+
+	if (w < 0 || w >= env->prog->len) {
+		verbose_linfo(env, t, "%d: ", t);
+		verbose(env, "jump out of range from insn %d to %d\n", t, w);
+		return -EINVAL;
+	}
+
+	if (e == BRANCH) {
+		/* mark branch target for state pruning */
+		mark_prune_point(env, w);
+		mark_jmp_point(env, w);
+	}
+
+	if (insn_state[w] == 0) {
+		/* tree-edge */
+		insn_state[t] = DISCOVERED | e;
+		insn_state[w] = DISCOVERED;
+		if (env->cfg.cur_stack >= env->prog->len)
+			return -E2BIG;
+		insn_stack[env->cfg.cur_stack++] = w;
+		return KEEP_EXPLORING;
+	} else if ((insn_state[w] & 0xF0) == DISCOVERED) {
+		if (loop_ok && env->bpf_capable)
+			return DONE_EXPLORING;
+		verbose_linfo(env, t, "%d: ", t);
+		verbose_linfo(env, w, "%d: ", w);
+		verbose(env, "back-edge from insn %d to %d\n", t, w);
+		return -EINVAL;
+	} else if (insn_state[w] == EXPLORED) {
+		/* forward- or cross-edge */
+		insn_state[t] = DISCOVERED | e;
+	} else {
+		verbose(env, "insn state internal bug\n");
+		return -EFAULT;
+	}
+	return DONE_EXPLORING;
+}
+
+static int visit_func_call_insn(int t, struct bpf_insn *insns,
+				struct bpf_verifier_env *env,
+				bool visit_callee)
+{
+	int ret, insn_sz;
+
+	insn_sz = bpf_is_ldimm64(&insns[t]) ? 2 : 1;
+	ret = push_insn(t, t + insn_sz, FALLTHROUGH, env, false);
+	if (ret)
+		return ret;
+
+	mark_prune_point(env, t + insn_sz);
+	/* when we exit from subprog, we need to record non-linear history */
+	mark_jmp_point(env, t + insn_sz);
+
+	if (visit_callee) {
+		mark_prune_point(env, t);
+		ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env,
+				/* It's ok to allow recursion from CFG point of
+				 * view. __check_func_call() will do the actual
+				 * check.
+				 */
+				bpf_pseudo_func(insns + t));
+	}
+	return ret;
+}
+
+/* Visits the instruction at index t and returns one of the following:
+ *  < 0 - an error occurred
+ *  DONE_EXPLORING - the instruction was fully explored
+ *  KEEP_EXPLORING - there is still work to be done before it is fully explored
+ */
+static int visit_insn(int t, struct bpf_verifier_env *env)
+{
+	struct bpf_insn *insns = env->prog->insnsi, *insn = &insns[t];
+	int ret, off, insn_sz;
+
+	if (bpf_pseudo_func(insn))
+		return visit_func_call_insn(t, insns, env, true);
+
+	/* All non-branch instructions have a single fall-through edge. */
+	if (BPF_CLASS(insn->code) != BPF_JMP &&
+	    BPF_CLASS(insn->code) != BPF_JMP32) {
+		insn_sz = bpf_is_ldimm64(insn) ? 2 : 1;
+		return push_insn(t, t + insn_sz, FALLTHROUGH, env, false);
+	}
+
+	switch (BPF_OP(insn->code)) {
+	case BPF_EXIT:
+		return DONE_EXPLORING;
+
+	case BPF_CALL:
+		if (insn->imm == BPF_FUNC_timer_set_callback)
+			/* Mark this call insn as a prune point to trigger
+			 * is_state_visited() check before call itself is
+			 * processed by __check_func_call(). Otherwise new
+			 * async state will be pushed for further exploration.
+			 */
+			mark_prune_point(env, t);
+		return visit_func_call_insn(t, insns, env, insn->src_reg == BPF_PSEUDO_CALL);
+
+	case BPF_JA:
+		if (BPF_SRC(insn->code) != BPF_K)
+			return -EINVAL;
+
+		if (BPF_CLASS(insn->code) == BPF_JMP)
+			off = insn->off;
+		else
+			off = insn->imm;
+
+		/* unconditional jump with single edge */
+		ret = push_insn(t, t + off + 1, FALLTHROUGH, env,
+				true);
+		if (ret)
+			return ret;
+
+		mark_prune_point(env, t + off + 1);
+		mark_jmp_point(env, t + off + 1);
+
+		return ret;
+
+	default:
+		/* conditional jump with two edges */
+		mark_prune_point(env, t);
+
+		ret = push_insn(t, t + 1, FALLTHROUGH, env, true);
+		if (ret)
+			return ret;
+
+		return push_insn(t, t + insn->off + 1, BRANCH, env, true);
+	}
+}
+
+/* non-recursive depth-first-search to detect loops in BPF program
+ * loop == back-edge in directed graph
+ */
+static int check_cfg(struct bpf_verifier_env *env)
+{
+	int insn_cnt = env->prog->len;
+	int *insn_stack, *insn_state;
+	int ret = 0;
+	int i;
+
+	insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
+	if (!insn_state)
+		return -ENOMEM;
+
+	insn_stack = env->cfg.insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
+	if (!insn_stack) {
+		kvfree(insn_state);
+		return -ENOMEM;
+	}
+
+	insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */
+	insn_stack[0] = 0; /* 0 is the first instruction */
+	env->cfg.cur_stack = 1;
+
+	while (env->cfg.cur_stack > 0) {
+		int t = insn_stack[env->cfg.cur_stack - 1];
+
+		ret = visit_insn(t, env);
+		switch (ret) {
+		case DONE_EXPLORING:
+			insn_state[t] = EXPLORED;
+			env->cfg.cur_stack--;
+			break;
+		case KEEP_EXPLORING:
+			break;
+		default:
+			if (ret > 0) {
+				verbose(env, "visit_insn internal bug\n");
+				ret = -EFAULT;
+			}
+			goto err_free;
+		}
+	}
+
+	if (env->cfg.cur_stack < 0) {
+		verbose(env, "pop stack internal bug\n");
+		ret = -EFAULT;
+		goto err_free;
+	}
+
+	for (i = 0; i < insn_cnt; i++) {
+		struct bpf_insn *insn = &env->prog->insnsi[i];
+
+		if (insn_state[i] != EXPLORED) {
+			verbose(env, "unreachable insn %d\n", i);
+			ret = -EINVAL;
+			goto err_free;
+		}
+		if (bpf_is_ldimm64(insn)) {
+			if (insn_state[i + 1] != 0) {
+				verbose(env, "jump into the middle of ldimm64 insn %d\n", i);
+				ret = -EINVAL;
+				goto err_free;
+			}
+			i++; /* skip second half of ldimm64 */
+		}
+	}
+	ret = 0; /* cfg looks good */
+
+err_free:
+	kvfree(insn_state);
+	kvfree(insn_stack);
+	env->cfg.insn_state = env->cfg.insn_stack = NULL;
+	return ret;
+}
+
+static int check_abnormal_return(struct bpf_verifier_env *env)
+{
+	int i;
+
+	for (i = 1; i < env->subprog_cnt; i++) {
+		if (env->subprog_info[i].has_ld_abs) {
+			verbose(env, "LD_ABS is not allowed in subprogs without BTF\n");
+			return -EINVAL;
+		}
+		if (env->subprog_info[i].has_tail_call) {
+			verbose(env, "tail_call is not allowed in subprogs without BTF\n");
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+/* The minimum supported BTF func info size */
+#define MIN_BPF_FUNCINFO_SIZE	8
+#define MAX_FUNCINFO_REC_SIZE	252
+
+static int check_btf_func(struct bpf_verifier_env *env,
+			  const union bpf_attr *attr,
+			  bpfptr_t uattr)
+{
+	const struct btf_type *type, *func_proto, *ret_type;
+	u32 i, nfuncs, urec_size, min_size;
+	u32 krec_size = sizeof(struct bpf_func_info);
+	struct bpf_func_info *krecord;
+	struct bpf_func_info_aux *info_aux = NULL;
+	struct bpf_prog *prog;
+	const struct btf *btf;
+	bpfptr_t urecord;
+	u32 prev_offset = 0;
+	bool scalar_return;
+	int ret = -ENOMEM;
+
+	nfuncs = attr->func_info_cnt;
+	if (!nfuncs) {
+		if (check_abnormal_return(env))
+			return -EINVAL;
+		return 0;
+	}
+
+	if (nfuncs != env->subprog_cnt) {
+		verbose(env, "number of funcs in func_info doesn't match number of subprogs\n");
+		return -EINVAL;
+	}
+
+	urec_size = attr->func_info_rec_size;
+	if (urec_size < MIN_BPF_FUNCINFO_SIZE ||
+	    urec_size > MAX_FUNCINFO_REC_SIZE ||
+	    urec_size % sizeof(u32)) {
+		verbose(env, "invalid func info rec size %u\n", urec_size);
+		return -EINVAL;
+	}
+
+	prog = env->prog;
+	btf = prog->aux->btf;
+
+	urecord = make_bpfptr(attr->func_info, uattr.is_kernel);
+	min_size = min_t(u32, krec_size, urec_size);
+
+	krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN);
+	if (!krecord)
+		return -ENOMEM;
+	info_aux = kcalloc(nfuncs, sizeof(*info_aux), GFP_KERNEL | __GFP_NOWARN);
+	if (!info_aux)
+		goto err_free;
+
+	for (i = 0; i < nfuncs; i++) {
+		ret = bpf_check_uarg_tail_zero(urecord, krec_size, urec_size);
+		if (ret) {
+			if (ret == -E2BIG) {
+				verbose(env, "nonzero tailing record in func info");
+				/* set the size kernel expects so loader can zero
+				 * out the rest of the record.
+				 */
+				if (copy_to_bpfptr_offset(uattr,
+							  offsetof(union bpf_attr, func_info_rec_size),
+							  &min_size, sizeof(min_size)))
+					ret = -EFAULT;
+			}
+			goto err_free;
+		}
+
+		if (copy_from_bpfptr(&krecord[i], urecord, min_size)) {
+			ret = -EFAULT;
+			goto err_free;
+		}
+
+		/* check insn_off */
+		ret = -EINVAL;
+		if (i == 0) {
+			if (krecord[i].insn_off) {
+				verbose(env,
+					"nonzero insn_off %u for the first func info record",
+					krecord[i].insn_off);
+				goto err_free;
+			}
+		} else if (krecord[i].insn_off <= prev_offset) {
+			verbose(env,
+				"same or smaller insn offset (%u) than previous func info record (%u)",
+				krecord[i].insn_off, prev_offset);
+			goto err_free;
+		}
+
+		if (env->subprog_info[i].start != krecord[i].insn_off) {
+			verbose(env, "func_info BTF section doesn't match subprog layout in BPF program\n");
+			goto err_free;
+		}
+
+		/* check type_id */
+		type = btf_type_by_id(btf, krecord[i].type_id);
+		if (!type || !btf_type_is_func(type)) {
+			verbose(env, "invalid type id %d in func info",
+				krecord[i].type_id);
+			goto err_free;
+		}
+		info_aux[i].linkage = BTF_INFO_VLEN(type->info);
+
+		func_proto = btf_type_by_id(btf, type->type);
+		if (unlikely(!func_proto || !btf_type_is_func_proto(func_proto)))
+			/* btf_func_check() already verified it during BTF load */
+			goto err_free;
+		ret_type = btf_type_skip_modifiers(btf, func_proto->type, NULL);
+		scalar_return =
+			btf_type_is_small_int(ret_type) || btf_is_any_enum(ret_type);
+		if (i && !scalar_return && env->subprog_info[i].has_ld_abs) {
+			verbose(env, "LD_ABS is only allowed in functions that return 'int'.\n");
+			goto err_free;
+		}
+		if (i && !scalar_return && env->subprog_info[i].has_tail_call) {
+			verbose(env, "tail_call is only allowed in functions that return 'int'.\n");
+			goto err_free;
+		}
+
+		prev_offset = krecord[i].insn_off;
+		bpfptr_add(&urecord, urec_size);
+	}
+
+	prog->aux->func_info = krecord;
+	prog->aux->func_info_cnt = nfuncs;
+	prog->aux->func_info_aux = info_aux;
+	return 0;
+
+err_free:
+	kvfree(krecord);
+	kfree(info_aux);
+	return ret;
+}
+
+static void adjust_btf_func(struct bpf_verifier_env *env)
+{
+	struct bpf_prog_aux *aux = env->prog->aux;
+	int i;
+
+	if (!aux->func_info)
+		return;
+
+	for (i = 0; i < env->subprog_cnt; i++)
+		aux->func_info[i].insn_off = env->subprog_info[i].start;
+}
+
+#define MIN_BPF_LINEINFO_SIZE	offsetofend(struct bpf_line_info, line_col)
+#define MAX_LINEINFO_REC_SIZE	MAX_FUNCINFO_REC_SIZE
+
+static int check_btf_line(struct bpf_verifier_env *env,
+			  const union bpf_attr *attr,
+			  bpfptr_t uattr)
+{
+	u32 i, s, nr_linfo, ncopy, expected_size, rec_size, prev_offset = 0;
+	struct bpf_subprog_info *sub;
+	struct bpf_line_info *linfo;
+	struct bpf_prog *prog;
+	const struct btf *btf;
+	bpfptr_t ulinfo;
+	int err;
+
+	nr_linfo = attr->line_info_cnt;
+	if (!nr_linfo)
+		return 0;
+	if (nr_linfo > INT_MAX / sizeof(struct bpf_line_info))
+		return -EINVAL;
+
+	rec_size = attr->line_info_rec_size;
+	if (rec_size < MIN_BPF_LINEINFO_SIZE ||
+	    rec_size > MAX_LINEINFO_REC_SIZE ||
+	    rec_size & (sizeof(u32) - 1))
+		return -EINVAL;
+
+	/* Need to zero it in case the userspace may
+	 * pass in a smaller bpf_line_info object.
+	 */
+	linfo = kvcalloc(nr_linfo, sizeof(struct bpf_line_info),
+			 GFP_KERNEL | __GFP_NOWARN);
+	if (!linfo)
+		return -ENOMEM;
+
+	prog = env->prog;
+	btf = prog->aux->btf;
+
+	s = 0;
+	sub = env->subprog_info;
+	ulinfo = make_bpfptr(attr->line_info, uattr.is_kernel);
+	expected_size = sizeof(struct bpf_line_info);
+	ncopy = min_t(u32, expected_size, rec_size);
+	for (i = 0; i < nr_linfo; i++) {
+		err = bpf_check_uarg_tail_zero(ulinfo, expected_size, rec_size);
+		if (err) {
+			if (err == -E2BIG) {
+				verbose(env, "nonzero tailing record in line_info");
+				if (copy_to_bpfptr_offset(uattr,
+							  offsetof(union bpf_attr, line_info_rec_size),
+							  &expected_size, sizeof(expected_size)))
+					err = -EFAULT;
+			}
+			goto err_free;
+		}
+
+		if (copy_from_bpfptr(&linfo[i], ulinfo, ncopy)) {
+			err = -EFAULT;
+			goto err_free;
+		}
+
+		/*
+		 * Check insn_off to ensure
+		 * 1) strictly increasing AND
+		 * 2) bounded by prog->len
+		 *
+		 * The linfo[0].insn_off == 0 check logically falls into
+		 * the later "missing bpf_line_info for func..." case
+		 * because the first linfo[0].insn_off must be the
+		 * first sub also and the first sub must have
+		 * subprog_info[0].start == 0.
+		 */
+		if ((i && linfo[i].insn_off <= prev_offset) ||
+		    linfo[i].insn_off >= prog->len) {
+			verbose(env, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n",
+				i, linfo[i].insn_off, prev_offset,
+				prog->len);
+			err = -EINVAL;
+			goto err_free;
+		}
+
+		if (!prog->insnsi[linfo[i].insn_off].code) {
+			verbose(env,
+				"Invalid insn code at line_info[%u].insn_off\n",
+				i);
+			err = -EINVAL;
+			goto err_free;
+		}
+
+		if (!btf_name_by_offset(btf, linfo[i].line_off) ||
+		    !btf_name_by_offset(btf, linfo[i].file_name_off)) {
+			verbose(env, "Invalid line_info[%u].line_off or .file_name_off\n", i);
+			err = -EINVAL;
+			goto err_free;
+		}
+
+		if (s != env->subprog_cnt) {
+			if (linfo[i].insn_off == sub[s].start) {
+				sub[s].linfo_idx = i;
+				s++;
+			} else if (sub[s].start < linfo[i].insn_off) {
+				verbose(env, "missing bpf_line_info for func#%u\n", s);
+				err = -EINVAL;
+				goto err_free;
+			}
+		}
+
+		prev_offset = linfo[i].insn_off;
+		bpfptr_add(&ulinfo, rec_size);
+	}
+
+	if (s != env->subprog_cnt) {
+		verbose(env, "missing bpf_line_info for %u funcs starting from func#%u\n",
+			env->subprog_cnt - s, s);
+		err = -EINVAL;
+		goto err_free;
+	}
+
+	prog->aux->linfo = linfo;
+	prog->aux->nr_linfo = nr_linfo;
+
+	return 0;
+
+err_free:
+	kvfree(linfo);
+	return err;
+}
+
+#define MIN_CORE_RELO_SIZE	sizeof(struct bpf_core_relo)
+#define MAX_CORE_RELO_SIZE	MAX_FUNCINFO_REC_SIZE
+
+static int check_core_relo(struct bpf_verifier_env *env,
+			   const union bpf_attr *attr,
+			   bpfptr_t uattr)
+{
+	u32 i, nr_core_relo, ncopy, expected_size, rec_size;
+	struct bpf_core_relo core_relo = {};
+	struct bpf_prog *prog = env->prog;
+	const struct btf *btf = prog->aux->btf;
+	struct bpf_core_ctx ctx = {
+		.log = &env->log,
+		.btf = btf,
+	};
+	bpfptr_t u_core_relo;
+	int err;
+
+	nr_core_relo = attr->core_relo_cnt;
+	if (!nr_core_relo)
+		return 0;
+	if (nr_core_relo > INT_MAX / sizeof(struct bpf_core_relo))
+		return -EINVAL;
+
+	rec_size = attr->core_relo_rec_size;
+	if (rec_size < MIN_CORE_RELO_SIZE ||
+	    rec_size > MAX_CORE_RELO_SIZE ||
+	    rec_size % sizeof(u32))
+		return -EINVAL;
+
+	u_core_relo = make_bpfptr(attr->core_relos, uattr.is_kernel);
+	expected_size = sizeof(struct bpf_core_relo);
+	ncopy = min_t(u32, expected_size, rec_size);
+
+	/* Unlike func_info and line_info, copy and apply each CO-RE
+	 * relocation record one at a time.
+	 */
+	for (i = 0; i < nr_core_relo; i++) {
+		/* future proofing when sizeof(bpf_core_relo) changes */
+		err = bpf_check_uarg_tail_zero(u_core_relo, expected_size, rec_size);
+		if (err) {
+			if (err == -E2BIG) {
+				verbose(env, "nonzero tailing record in core_relo");
+				if (copy_to_bpfptr_offset(uattr,
+							  offsetof(union bpf_attr, core_relo_rec_size),
+							  &expected_size, sizeof(expected_size)))
+					err = -EFAULT;
+			}
+			break;
+		}
+
+		if (copy_from_bpfptr(&core_relo, u_core_relo, ncopy)) {
+			err = -EFAULT;
+			break;
+		}
+
+		if (core_relo.insn_off % 8 || core_relo.insn_off / 8 >= prog->len) {
+			verbose(env, "Invalid core_relo[%u].insn_off:%u prog->len:%u\n",
+				i, core_relo.insn_off, prog->len);
+			err = -EINVAL;
+			break;
+		}
+
+		err = bpf_core_apply(&ctx, &core_relo, i,
+				     &prog->insnsi[core_relo.insn_off / 8]);
+		if (err)
+			break;
+		bpfptr_add(&u_core_relo, rec_size);
+	}
+	return err;
+}
+
+static int check_btf_info(struct bpf_verifier_env *env,
+			  const union bpf_attr *attr,
+			  bpfptr_t uattr)
+{
+	struct btf *btf;
+	int err;
+
+	if (!attr->func_info_cnt && !attr->line_info_cnt) {
+		if (check_abnormal_return(env))
+			return -EINVAL;
+		return 0;
+	}
+
+	btf = btf_get_by_fd(attr->prog_btf_fd);
+	if (IS_ERR(btf))
+		return PTR_ERR(btf);
+	if (btf_is_kernel(btf)) {
+		btf_put(btf);
+		return -EACCES;
+	}
+	env->prog->aux->btf = btf;
+
+	err = check_btf_func(env, attr, uattr);
+	if (err)
+		return err;
+
+	err = check_btf_line(env, attr, uattr);
+	if (err)
+		return err;
+
+	err = check_core_relo(env, attr, uattr);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+/* check %cur's range satisfies %old's */
+static bool range_within(struct bpf_reg_state *old,
+			 struct bpf_reg_state *cur)
+{
+	return old->umin_value <= cur->umin_value &&
+	       old->umax_value >= cur->umax_value &&
+	       old->smin_value <= cur->smin_value &&
+	       old->smax_value >= cur->smax_value &&
+	       old->u32_min_value <= cur->u32_min_value &&
+	       old->u32_max_value >= cur->u32_max_value &&
+	       old->s32_min_value <= cur->s32_min_value &&
+	       old->s32_max_value >= cur->s32_max_value;
+}
+
+/* If in the old state two registers had the same id, then they need to have
+ * the same id in the new state as well.  But that id could be different from
+ * the old state, so we need to track the mapping from old to new ids.
+ * Once we have seen that, say, a reg with old id 5 had new id 9, any subsequent
+ * regs with old id 5 must also have new id 9 for the new state to be safe.  But
+ * regs with a different old id could still have new id 9, we don't care about
+ * that.
+ * So we look through our idmap to see if this old id has been seen before.  If
+ * so, we require the new id to match; otherwise, we add the id pair to the map.
+ */
+static bool check_ids(u32 old_id, u32 cur_id, struct bpf_id_pair *idmap)
+{
+	unsigned int i;
+
+	for (i = 0; i < BPF_ID_MAP_SIZE; i++) {
+		if (!idmap[i].old) {
+			/* Reached an empty slot; haven't seen this id before */
+			idmap[i].old = old_id;
+			idmap[i].cur = cur_id;
+			return true;
+		}
+		if (idmap[i].old == old_id)
+			return idmap[i].cur == cur_id;
+	}
+	/* We ran out of idmap slots, which should be impossible */
+	WARN_ON_ONCE(1);
+	return false;
+}
+
+static void clean_func_state(struct bpf_verifier_env *env,
+			     struct bpf_func_state *st)
+{
+	enum bpf_reg_liveness live;
+	int i, j;
+
+	for (i = 0; i < BPF_REG_FP; i++) {
+		live = st->regs[i].live;
+		/* liveness must not touch this register anymore */
+		st->regs[i].live |= REG_LIVE_DONE;
+		if (!(live & REG_LIVE_READ))
+			/* since the register is unused, clear its state
+			 * to make further comparison simpler
+			 */
+			__mark_reg_not_init(env, &st->regs[i]);
+	}
+
+	for (i = 0; i < st->allocated_stack / BPF_REG_SIZE; i++) {
+		live = st->stack[i].spilled_ptr.live;
+		/* liveness must not touch this stack slot anymore */
+		st->stack[i].spilled_ptr.live |= REG_LIVE_DONE;
+		if (!(live & REG_LIVE_READ)) {
+			__mark_reg_not_init(env, &st->stack[i].spilled_ptr);
+			for (j = 0; j < BPF_REG_SIZE; j++)
+				st->stack[i].slot_type[j] = STACK_INVALID;
+		}
+	}
+}
+
+static void clean_verifier_state(struct bpf_verifier_env *env,
+				 struct bpf_verifier_state *st)
+{
+	int i;
+
+	if (st->frame[0]->regs[0].live & REG_LIVE_DONE)
+		/* all regs in this state in all frames were already marked */
+		return;
+
+	for (i = 0; i <= st->curframe; i++)
+		clean_func_state(env, st->frame[i]);
+}
+
+/* the parentage chains form a tree.
+ * the verifier states are added to state lists at given insn and
+ * pushed into state stack for future exploration.
+ * when the verifier reaches bpf_exit insn some of the verifer states
+ * stored in the state lists have their final liveness state already,
+ * but a lot of states will get revised from liveness point of view when
+ * the verifier explores other branches.
+ * Example:
+ * 1: r0 = 1
+ * 2: if r1 == 100 goto pc+1
+ * 3: r0 = 2
+ * 4: exit
+ * when the verifier reaches exit insn the register r0 in the state list of
+ * insn 2 will be seen as !REG_LIVE_READ. Then the verifier pops the other_branch
+ * of insn 2 and goes exploring further. At the insn 4 it will walk the
+ * parentage chain from insn 4 into insn 2 and will mark r0 as REG_LIVE_READ.
+ *
+ * Since the verifier pushes the branch states as it sees them while exploring
+ * the program the condition of walking the branch instruction for the second
+ * time means that all states below this branch were already explored and
+ * their final liveness marks are already propagated.
+ * Hence when the verifier completes the search of state list in is_state_visited()
+ * we can call this clean_live_states() function to mark all liveness states
+ * as REG_LIVE_DONE to indicate that 'parent' pointers of 'struct bpf_reg_state'
+ * will not be used.
+ * This function also clears the registers and stack for states that !READ
+ * to simplify state merging.
+ *
+ * Important note here that walking the same branch instruction in the callee
+ * doesn't meant that the states are DONE. The verifier has to compare
+ * the callsites
+ */
+static void clean_live_states(struct bpf_verifier_env *env, int insn,
+			      struct bpf_verifier_state *cur)
+{
+	struct bpf_verifier_state_list *sl;
+	int i;
+
+	sl = *explored_state(env, insn);
+	while (sl) {
+		if (sl->state.branches)
+			goto next;
+		if (sl->state.insn_idx != insn ||
+		    sl->state.curframe != cur->curframe)
+			goto next;
+		for (i = 0; i <= cur->curframe; i++)
+			if (sl->state.frame[i]->callsite != cur->frame[i]->callsite)
+				goto next;
+		clean_verifier_state(env, &sl->state);
+next:
+		sl = sl->next;
+	}
+}
+
+/* Returns true if (rold safe implies rcur safe) */
+static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold,
+		    struct bpf_reg_state *rcur, struct bpf_id_pair *idmap)
+{
+	bool equal;
+
+	if (!(rold->live & REG_LIVE_READ))
+		/* explored state didn't use this */
+		return true;
+
+	equal = memcmp(rold, rcur, offsetof(struct bpf_reg_state, parent)) == 0;
+
+	if (rold->type == PTR_TO_STACK)
+		/* two stack pointers are equal only if they're pointing to
+		 * the same stack frame, since fp-8 in foo != fp-8 in bar
+		 */
+		return equal && rold->frameno == rcur->frameno;
+
+	if (equal)
+		return true;
+
+	if (rold->type == NOT_INIT)
+		/* explored state can't have used this */
+		return true;
+	if (rcur->type == NOT_INIT)
+		return false;
+	switch (base_type(rold->type)) {
+	case SCALAR_VALUE:
+		if (env->explore_alu_limits)
+			return false;
+		if (rcur->type == SCALAR_VALUE) {
+			if (!rold->precise)
+				return true;
+			/* new val must satisfy old val knowledge */
+			return range_within(rold, rcur) &&
+			       tnum_in(rold->var_off, rcur->var_off);
+		} else {
+			/* We're trying to use a pointer in place of a scalar.
+			 * Even if the scalar was unbounded, this could lead to
+			 * pointer leaks because scalars are allowed to leak
+			 * while pointers are not. We could make this safe in
+			 * special cases if root is calling us, but it's
+			 * probably not worth the hassle.
+			 */
+			return false;
+		}
+	case PTR_TO_MAP_KEY:
+	case PTR_TO_MAP_VALUE:
+		/* a PTR_TO_MAP_VALUE could be safe to use as a
+		 * PTR_TO_MAP_VALUE_OR_NULL into the same map.
+		 * However, if the old PTR_TO_MAP_VALUE_OR_NULL then got NULL-
+		 * checked, doing so could have affected others with the same
+		 * id, and we can't check for that because we lost the id when
+		 * we converted to a PTR_TO_MAP_VALUE.
+		 */
+		if (type_may_be_null(rold->type)) {
+			if (!type_may_be_null(rcur->type))
+				return false;
+			if (memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)))
+				return false;
+			/* Check our ids match any regs they're supposed to */
+			return check_ids(rold->id, rcur->id, idmap);
+		}
+
+		/* If the new min/max/var_off satisfy the old ones and
+		 * everything else matches, we are OK.
+		 * 'id' is not compared, since it's only used for maps with
+		 * bpf_spin_lock inside map element and in such cases if
+		 * the rest of the prog is valid for one map element then
+		 * it's valid for all map elements regardless of the key
+		 * used in bpf_map_lookup()
+		 */
+		return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 &&
+		       range_within(rold, rcur) &&
+		       tnum_in(rold->var_off, rcur->var_off);
+	case PTR_TO_PACKET_META:
+	case PTR_TO_PACKET:
+		if (rcur->type != rold->type)
+			return false;
+		/* We must have at least as much range as the old ptr
+		 * did, so that any accesses which were safe before are
+		 * still safe.  This is true even if old range < old off,
+		 * since someone could have accessed through (ptr - k), or
+		 * even done ptr -= k in a register, to get a safe access.
+		 */
+		if (rold->range > rcur->range)
+			return false;
+		/* If the offsets don't match, we can't trust our alignment;
+		 * nor can we be sure that we won't fall out of range.
+		 */
+		if (rold->off != rcur->off)
+			return false;
+		/* id relations must be preserved */
+		if (rold->id && !check_ids(rold->id, rcur->id, idmap))
+			return false;
+		/* new val must satisfy old val knowledge */
+		return range_within(rold, rcur) &&
+		       tnum_in(rold->var_off, rcur->var_off);
+	case PTR_TO_CTX:
+	case CONST_PTR_TO_MAP:
+	case PTR_TO_PACKET_END:
+	case PTR_TO_FLOW_KEYS:
+	case PTR_TO_SOCKET:
+	case PTR_TO_SOCK_COMMON:
+	case PTR_TO_TCP_SOCK:
+	case PTR_TO_XDP_SOCK:
+		/* Only valid matches are exact, which memcmp() above
+		 * would have accepted
+		 */
+	default:
+		/* Don't know what's going on, just say it's not safe */
+		return false;
+	}
+
+	/* Shouldn't get here; if we do, say it's not safe */
+	WARN_ON_ONCE(1);
+	return false;
+}
+
+static bool stacksafe(struct bpf_verifier_env *env, struct bpf_func_state *old,
+		      struct bpf_func_state *cur, struct bpf_id_pair *idmap)
+{
+	int i, spi;
+
+	/* walk slots of the explored stack and ignore any additional
+	 * slots in the current stack, since explored(safe) state
+	 * didn't use them
+	 */
+	for (i = 0; i < old->allocated_stack; i++) {
+		spi = i / BPF_REG_SIZE;
+
+		if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ)) {
+			i += BPF_REG_SIZE - 1;
+			/* explored state didn't use this */
+			continue;
+		}
+
+		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_INVALID)
+			continue;
+
+		/* explored stack has more populated slots than current stack
+		 * and these slots were used
+		 */
+		if (i >= cur->allocated_stack)
+			return false;
+
+		/* if old state was safe with misc data in the stack
+		 * it will be safe with zero-initialized stack.
+		 * The opposite is not true
+		 */
+		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC &&
+		    cur->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_ZERO)
+			continue;
+		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] !=
+		    cur->stack[spi].slot_type[i % BPF_REG_SIZE])
+			/* Ex: old explored (safe) state has STACK_SPILL in
+			 * this stack slot, but current has STACK_MISC ->
+			 * this verifier states are not equivalent,
+			 * return false to continue verification of this path
+			 */
+			return false;
+		if (i % BPF_REG_SIZE != BPF_REG_SIZE - 1)
+			continue;
+		if (!is_spilled_reg(&old->stack[spi]))
+			continue;
+		if (!regsafe(env, &old->stack[spi].spilled_ptr,
+			     &cur->stack[spi].spilled_ptr, idmap))
+			/* when explored and current stack slot are both storing
+			 * spilled registers, check that stored pointers types
+			 * are the same as well.
+			 * Ex: explored safe path could have stored
+			 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8}
+			 * but current path has stored:
+			 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16}
+			 * such verifier states are not equivalent.
+			 * return false to continue verification of this path
+			 */
+			return false;
+	}
+	return true;
+}
+
+static bool refsafe(struct bpf_func_state *old, struct bpf_func_state *cur)
+{
+	if (old->acquired_refs != cur->acquired_refs)
+		return false;
+	return !memcmp(old->refs, cur->refs,
+		       sizeof(*old->refs) * old->acquired_refs);
+}
+
+/* compare two verifier states
+ *
+ * all states stored in state_list are known to be valid, since
+ * verifier reached 'bpf_exit' instruction through them
+ *
+ * this function is called when verifier exploring different branches of
+ * execution popped from the state stack. If it sees an old state that has
+ * more strict register state and more strict stack state then this execution
+ * branch doesn't need to be explored further, since verifier already
+ * concluded that more strict state leads to valid finish.
+ *
+ * Therefore two states are equivalent if register state is more conservative
+ * and explored stack state is more conservative than the current one.
+ * Example:
+ *       explored                   current
+ * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC)
+ * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC)
+ *
+ * In other words if current stack state (one being explored) has more
+ * valid slots than old one that already passed validation, it means
+ * the verifier can stop exploring and conclude that current state is valid too
+ *
+ * Similarly with registers. If explored state has register type as invalid
+ * whereas register type in current state is meaningful, it means that
+ * the current state will reach 'bpf_exit' instruction safely
+ */
+static bool func_states_equal(struct bpf_verifier_env *env, struct bpf_func_state *old,
+			      struct bpf_func_state *cur)
+{
+	int i;
+
+	memset(env->idmap_scratch, 0, sizeof(env->idmap_scratch));
+	for (i = 0; i < MAX_BPF_REG; i++)
+		if (!regsafe(env, &old->regs[i], &cur->regs[i],
+			     env->idmap_scratch))
+			return false;
+
+	if (!stacksafe(env, old, cur, env->idmap_scratch))
+		return false;
+
+	if (!refsafe(old, cur))
+		return false;
+
+	return true;
+}
+
+static bool states_equal(struct bpf_verifier_env *env,
+			 struct bpf_verifier_state *old,
+			 struct bpf_verifier_state *cur)
+{
+	int i;
+
+	if (old->curframe != cur->curframe)
+		return false;
+
+	/* Verification state from speculative execution simulation
+	 * must never prune a non-speculative execution one.
+	 */
+	if (old->speculative && !cur->speculative)
+		return false;
+
+	if (old->active_spin_lock != cur->active_spin_lock)
+		return false;
+
+	/* for states to be equal callsites have to be the same
+	 * and all frame states need to be equivalent
+	 */
+	for (i = 0; i <= old->curframe; i++) {
+		if (old->frame[i]->callsite != cur->frame[i]->callsite)
+			return false;
+		if (!func_states_equal(env, old->frame[i], cur->frame[i]))
+			return false;
+	}
+	return true;
+}
+
+/* Return 0 if no propagation happened. Return negative error code if error
+ * happened. Otherwise, return the propagated bit.
+ */
+static int propagate_liveness_reg(struct bpf_verifier_env *env,
+				  struct bpf_reg_state *reg,
+				  struct bpf_reg_state *parent_reg)
+{
+	u8 parent_flag = parent_reg->live & REG_LIVE_READ;
+	u8 flag = reg->live & REG_LIVE_READ;
+	int err;
+
+	/* When comes here, read flags of PARENT_REG or REG could be any of
+	 * REG_LIVE_READ64, REG_LIVE_READ32, REG_LIVE_NONE. There is no need
+	 * of propagation if PARENT_REG has strongest REG_LIVE_READ64.
+	 */
+	if (parent_flag == REG_LIVE_READ64 ||
+	    /* Or if there is no read flag from REG. */
+	    !flag ||
+	    /* Or if the read flag from REG is the same as PARENT_REG. */
+	    parent_flag == flag)
+		return 0;
+
+	err = mark_reg_read(env, reg, parent_reg, flag);
+	if (err)
+		return err;
+
+	return flag;
+}
+
+/* A write screens off any subsequent reads; but write marks come from the
+ * straight-line code between a state and its parent.  When we arrive at an
+ * equivalent state (jump target or such) we didn't arrive by the straight-line
+ * code, so read marks in the state must propagate to the parent regardless
+ * of the state's write marks. That's what 'parent == state->parent' comparison
+ * in mark_reg_read() is for.
+ */
+static int propagate_liveness(struct bpf_verifier_env *env,
+			      const struct bpf_verifier_state *vstate,
+			      struct bpf_verifier_state *vparent)
+{
+	struct bpf_reg_state *state_reg, *parent_reg;
+	struct bpf_func_state *state, *parent;
+	int i, frame, err = 0;
+
+	if (vparent->curframe != vstate->curframe) {
+		WARN(1, "propagate_live: parent frame %d current frame %d\n",
+		     vparent->curframe, vstate->curframe);
+		return -EFAULT;
+	}
+	/* Propagate read liveness of registers... */
+	BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
+	for (frame = 0; frame <= vstate->curframe; frame++) {
+		parent = vparent->frame[frame];
+		state = vstate->frame[frame];
+		parent_reg = parent->regs;
+		state_reg = state->regs;
+		/* We don't need to worry about FP liveness, it's read-only */
+		for (i = frame < vstate->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) {
+			err = propagate_liveness_reg(env, &state_reg[i],
+						     &parent_reg[i]);
+			if (err < 0)
+				return err;
+			if (err == REG_LIVE_READ64)
+				mark_insn_zext(env, &parent_reg[i]);
+		}
+
+		/* Propagate stack slots. */
+		for (i = 0; i < state->allocated_stack / BPF_REG_SIZE &&
+			    i < parent->allocated_stack / BPF_REG_SIZE; i++) {
+			parent_reg = &parent->stack[i].spilled_ptr;
+			state_reg = &state->stack[i].spilled_ptr;
+			err = propagate_liveness_reg(env, state_reg,
+						     parent_reg);
+			if (err < 0)
+				return err;
+		}
+	}
+	return 0;
+}
+
+/* find precise scalars in the previous equivalent state and
+ * propagate them into the current state
+ */
+static int propagate_precision(struct bpf_verifier_env *env,
+			       const struct bpf_verifier_state *old)
+{
+	struct bpf_reg_state *state_reg;
+	struct bpf_func_state *state;
+	int i, err = 0, fr;
+
+	for (fr = old->curframe; fr >= 0; fr--) {
+		state = old->frame[fr];
+		state_reg = state->regs;
+		for (i = 0; i < BPF_REG_FP; i++, state_reg++) {
+			if (state_reg->type != SCALAR_VALUE ||
+			    !state_reg->precise ||
+			    !(state_reg->live & REG_LIVE_READ))
+				continue;
+			if (env->log.level & BPF_LOG_LEVEL2)
+				verbose(env, "frame %d: propagating r%d\n", fr, i);
+			err = mark_chain_precision_frame(env, fr, i);
+			if (err < 0)
+				return err;
+		}
+
+		for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+			if (!is_spilled_reg(&state->stack[i]))
+				continue;
+			state_reg = &state->stack[i].spilled_ptr;
+			if (state_reg->type != SCALAR_VALUE ||
+			    !state_reg->precise ||
+			    !(state_reg->live & REG_LIVE_READ))
+				continue;
+			if (env->log.level & BPF_LOG_LEVEL2)
+				verbose(env, "frame %d: propagating fp%d\n",
+					fr, (-i - 1) * BPF_REG_SIZE);
+			err = mark_chain_precision_stack_frame(env, fr, i);
+			if (err < 0)
+				return err;
+		}
+	}
+	return 0;
+}
+
+static bool states_maybe_looping(struct bpf_verifier_state *old,
+				 struct bpf_verifier_state *cur)
+{
+	struct bpf_func_state *fold, *fcur;
+	int i, fr = cur->curframe;
+
+	if (old->curframe != fr)
+		return false;
+
+	fold = old->frame[fr];
+	fcur = cur->frame[fr];
+	for (i = 0; i < MAX_BPF_REG; i++)
+		if (memcmp(&fold->regs[i], &fcur->regs[i],
+			   offsetof(struct bpf_reg_state, parent)))
+			return false;
+	return true;
+}
+
+
+static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
+{
+	struct bpf_verifier_state_list *new_sl;
+	struct bpf_verifier_state_list *sl, **pprev;
+	struct bpf_verifier_state *cur = env->cur_state, *new;
+	int i, j, err, states_cnt = 0;
+	bool add_new_state = env->test_state_freq ? true : false;
+
+	cur->last_insn_idx = env->prev_insn_idx;
+	if (!is_prune_point(env, insn_idx))
+		/* this 'insn_idx' instruction wasn't marked, so we will not
+		 * be doing state search here
+		 */
+		return push_jmp_history(env, cur);
+
+	/* bpf progs typically have pruning point every 4 instructions
+	 * http://vger.kernel.org/bpfconf2019.html#session-1
+	 * Do not add new state for future pruning if the verifier hasn't seen
+	 * at least 2 jumps and at least 8 instructions.
+	 * This heuristics helps decrease 'total_states' and 'peak_states' metric.
+	 * In tests that amounts to up to 50% reduction into total verifier
+	 * memory consumption and 20% verifier time speedup.
+	 */
+	if (env->jmps_processed - env->prev_jmps_processed >= 2 &&
+	    env->insn_processed - env->prev_insn_processed >= 8)
+		add_new_state = true;
+
+	pprev = explored_state(env, insn_idx);
+	sl = *pprev;
+
+	clean_live_states(env, insn_idx, cur);
+
+	while (sl) {
+		states_cnt++;
+		if (sl->state.insn_idx != insn_idx)
+			goto next;
+
+		if (sl->state.branches) {
+			struct bpf_func_state *frame = sl->state.frame[sl->state.curframe];
+
+			if (frame->in_async_callback_fn &&
+			    frame->async_entry_cnt != cur->frame[cur->curframe]->async_entry_cnt) {
+				/* Different async_entry_cnt means that the verifier is
+				 * processing another entry into async callback.
+				 * Seeing the same state is not an indication of infinite
+				 * loop or infinite recursion.
+				 * But finding the same state doesn't mean that it's safe
+				 * to stop processing the current state. The previous state
+				 * hasn't yet reached bpf_exit, since state.branches > 0.
+				 * Checking in_async_callback_fn alone is not enough either.
+				 * Since the verifier still needs to catch infinite loops
+				 * inside async callbacks.
+				 */
+			} else if (states_maybe_looping(&sl->state, cur) &&
+				   states_equal(env, &sl->state, cur)) {
+				verbose_linfo(env, insn_idx, "; ");
+				verbose(env, "infinite loop detected at insn %d\n", insn_idx);
+				return -EINVAL;
+			}
+			/* if the verifier is processing a loop, avoid adding new state
+			 * too often, since different loop iterations have distinct
+			 * states and may not help future pruning.
+			 * This threshold shouldn't be too low to make sure that
+			 * a loop with large bound will be rejected quickly.
+			 * The most abusive loop will be:
+			 * r1 += 1
+			 * if r1 < 1000000 goto pc-2
+			 * 1M insn_procssed limit / 100 == 10k peak states.
+			 * This threshold shouldn't be too high either, since states
+			 * at the end of the loop are likely to be useful in pruning.
+			 */
+			if (env->jmps_processed - env->prev_jmps_processed < 20 &&
+			    env->insn_processed - env->prev_insn_processed < 100)
+				add_new_state = false;
+			goto miss;
+		}
+		if (states_equal(env, &sl->state, cur)) {
+			sl->hit_cnt++;
+			/* reached equivalent register/stack state,
+			 * prune the search.
+			 * Registers read by the continuation are read by us.
+			 * If we have any write marks in env->cur_state, they
+			 * will prevent corresponding reads in the continuation
+			 * from reaching our parent (an explored_state).  Our
+			 * own state will get the read marks recorded, but
+			 * they'll be immediately forgotten as we're pruning
+			 * this state and will pop a new one.
+			 */
+			err = propagate_liveness(env, &sl->state, cur);
+
+			/* if previous state reached the exit with precision and
+			 * current state is equivalent to it (except precsion marks)
+			 * the precision needs to be propagated back in
+			 * the current state.
+			 */
+			err = err ? : push_jmp_history(env, cur);
+			err = err ? : propagate_precision(env, &sl->state);
+			if (err)
+				return err;
+			return 1;
+		}
+miss:
+		/* when new state is not going to be added do not increase miss count.
+		 * Otherwise several loop iterations will remove the state
+		 * recorded earlier. The goal of these heuristics is to have
+		 * states from some iterations of the loop (some in the beginning
+		 * and some at the end) to help pruning.
+		 */
+		if (add_new_state)
+			sl->miss_cnt++;
+		/* heuristic to determine whether this state is beneficial
+		 * to keep checking from state equivalence point of view.
+		 * Higher numbers increase max_states_per_insn and verification time,
+		 * but do not meaningfully decrease insn_processed.
+		 */
+		if (sl->miss_cnt > sl->hit_cnt * 3 + 3) {
+			/* the state is unlikely to be useful. Remove it to
+			 * speed up verification
+			 */
+			*pprev = sl->next;
+			if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE) {
+				u32 br = sl->state.branches;
+
+				WARN_ONCE(br,
+					  "BUG live_done but branches_to_explore %d\n",
+					  br);
+				free_verifier_state(&sl->state, false);
+				kfree(sl);
+				env->peak_states--;
+			} else {
+				/* cannot free this state, since parentage chain may
+				 * walk it later. Add it for free_list instead to
+				 * be freed at the end of verification
+				 */
+				sl->next = env->free_list;
+				env->free_list = sl;
+			}
+			sl = *pprev;
+			continue;
+		}
+next:
+		pprev = &sl->next;
+		sl = *pprev;
+	}
+
+	if (env->max_states_per_insn < states_cnt)
+		env->max_states_per_insn = states_cnt;
+
+	if (!env->bpf_capable && states_cnt > BPF_COMPLEXITY_LIMIT_STATES)
+		return push_jmp_history(env, cur);
+
+	if (!add_new_state)
+		return push_jmp_history(env, cur);
+
+	/* There were no equivalent states, remember the current one.
+	 * Technically the current state is not proven to be safe yet,
+	 * but it will either reach outer most bpf_exit (which means it's safe)
+	 * or it will be rejected. When there are no loops the verifier won't be
+	 * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx)
+	 * again on the way to bpf_exit.
+	 * When looping the sl->state.branches will be > 0 and this state
+	 * will not be considered for equivalence until branches == 0.
+	 */
+	new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL);
+	if (!new_sl)
+		return -ENOMEM;
+	env->total_states++;
+	env->peak_states++;
+	env->prev_jmps_processed = env->jmps_processed;
+	env->prev_insn_processed = env->insn_processed;
+
+	/* forget precise markings we inherited, see __mark_chain_precision */
+	if (env->bpf_capable)
+		mark_all_scalars_imprecise(env, cur);
+
+	/* add new state to the head of linked list */
+	new = &new_sl->state;
+	err = copy_verifier_state(new, cur);
+	if (err) {
+		free_verifier_state(new, false);
+		kfree(new_sl);
+		return err;
+	}
+	new->insn_idx = insn_idx;
+	WARN_ONCE(new->branches != 1,
+		  "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches, insn_idx);
+
+	cur->parent = new;
+	cur->first_insn_idx = insn_idx;
+	clear_jmp_history(cur);
+	new_sl->next = *explored_state(env, insn_idx);
+	*explored_state(env, insn_idx) = new_sl;
+	/* connect new state to parentage chain. Current frame needs all
+	 * registers connected. Only r6 - r9 of the callers are alive (pushed
+	 * to the stack implicitly by JITs) so in callers' frames connect just
+	 * r6 - r9 as an optimization. Callers will have r1 - r5 connected to
+	 * the state of the call instruction (with WRITTEN set), and r0 comes
+	 * from callee with its full parentage chain, anyway.
+	 */
+	/* clear write marks in current state: the writes we did are not writes
+	 * our child did, so they don't screen off its reads from us.
+	 * (There are no read marks in current state, because reads always mark
+	 * their parent and current state never has children yet.  Only
+	 * explored_states can get read marks.)
+	 */
+	for (j = 0; j <= cur->curframe; j++) {
+		for (i = j < cur->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++)
+			cur->frame[j]->regs[i].parent = &new->frame[j]->regs[i];
+		for (i = 0; i < BPF_REG_FP; i++)
+			cur->frame[j]->regs[i].live = REG_LIVE_NONE;
+	}
+
+	/* all stack frames are accessible from callee, clear them all */
+	for (j = 0; j <= cur->curframe; j++) {
+		struct bpf_func_state *frame = cur->frame[j];
+		struct bpf_func_state *newframe = new->frame[j];
+
+		for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++) {
+			frame->stack[i].spilled_ptr.live = REG_LIVE_NONE;
+			frame->stack[i].spilled_ptr.parent =
+						&newframe->stack[i].spilled_ptr;
+		}
+	}
+	return 0;
+}
+
+/* Return true if it's OK to have the same insn return a different type. */
+static bool reg_type_mismatch_ok(enum bpf_reg_type type)
+{
+	switch (base_type(type)) {
+	case PTR_TO_CTX:
+	case PTR_TO_SOCKET:
+	case PTR_TO_SOCK_COMMON:
+	case PTR_TO_TCP_SOCK:
+	case PTR_TO_XDP_SOCK:
+	case PTR_TO_BTF_ID:
+		return false;
+	default:
+		return true;
+	}
+}
+
+/* If an instruction was previously used with particular pointer types, then we
+ * need to be careful to avoid cases such as the below, where it may be ok
+ * for one branch accessing the pointer, but not ok for the other branch:
+ *
+ * R1 = sock_ptr
+ * goto X;
+ * ...
+ * R1 = some_other_valid_ptr;
+ * goto X;
+ * ...
+ * R2 = *(u32 *)(R1 + 0);
+ */
+static bool reg_type_mismatch(enum bpf_reg_type src, enum bpf_reg_type prev)
+{
+	return src != prev && (!reg_type_mismatch_ok(src) ||
+			       !reg_type_mismatch_ok(prev));
+}
+
+static int do_check(struct bpf_verifier_env *env)
+{
+	bool pop_log = !(env->log.level & BPF_LOG_LEVEL2);
+	struct bpf_verifier_state *state = env->cur_state;
+	struct bpf_insn *insns = env->prog->insnsi;
+	struct bpf_reg_state *regs;
+	int insn_cnt = env->prog->len;
+	bool do_print_state = false;
+	int prev_insn_idx = -1;
+
+	for (;;) {
+		struct bpf_insn *insn;
+		u8 class;
+		int err;
+
+		env->prev_insn_idx = prev_insn_idx;
+		if (env->insn_idx >= insn_cnt) {
+			verbose(env, "invalid insn idx %d insn_cnt %d\n",
+				env->insn_idx, insn_cnt);
+			return -EFAULT;
+		}
+
+		insn = &insns[env->insn_idx];
+		class = BPF_CLASS(insn->code);
+
+		if (++env->insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) {
+			verbose(env,
+				"BPF program is too large. Processed %d insn\n",
+				env->insn_processed);
+			return -E2BIG;
+		}
+
+		err = is_state_visited(env, env->insn_idx);
+		if (err < 0)
+			return err;
+		if (err == 1) {
+			/* found equivalent state, can prune the search */
+			if (env->log.level & BPF_LOG_LEVEL) {
+				if (do_print_state)
+					verbose(env, "\nfrom %d to %d%s: safe\n",
+						env->prev_insn_idx, env->insn_idx,
+						env->cur_state->speculative ?
+						" (speculative execution)" : "");
+				else
+					verbose(env, "%d: safe\n", env->insn_idx);
+			}
+			goto process_bpf_exit;
+		}
+
+		if (signal_pending(current))
+			return -EAGAIN;
+
+		if (need_resched())
+			cond_resched();
+
+		if (env->log.level & BPF_LOG_LEVEL2 && do_print_state) {
+			verbose(env, "\nfrom %d to %d%s:",
+				env->prev_insn_idx, env->insn_idx,
+				env->cur_state->speculative ?
+				" (speculative execution)" : "");
+			print_verifier_state(env, state->frame[state->curframe], true);
+			do_print_state = false;
+		}
+
+		if (env->log.level & BPF_LOG_LEVEL) {
+			const struct bpf_insn_cbs cbs = {
+				.cb_call	= disasm_kfunc_name,
+				.cb_print	= verbose,
+				.private_data	= env,
+			};
+
+			if (verifier_state_scratched(env))
+				print_insn_state(env, state->frame[state->curframe]);
+
+			verbose_linfo(env, env->insn_idx, "; ");
+			env->prev_log_len = env->log.len_used;
+			verbose(env, "%d: ", env->insn_idx);
+			print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
+			env->prev_insn_print_len = env->log.len_used - env->prev_log_len;
+			env->prev_log_len = env->log.len_used;
+		}
+
+		if (bpf_prog_is_dev_bound(env->prog->aux)) {
+			err = bpf_prog_offload_verify_insn(env, env->insn_idx,
+							   env->prev_insn_idx);
+			if (err)
+				return err;
+		}
+
+		regs = cur_regs(env);
+		sanitize_mark_insn_seen(env);
+		prev_insn_idx = env->insn_idx;
+
+		if (class == BPF_ALU || class == BPF_ALU64) {
+			err = check_alu_op(env, insn);
+			if (err)
+				return err;
+
+		} else if (class == BPF_LDX) {
+			enum bpf_reg_type *prev_src_type, src_reg_type;
+
+			/* check for reserved fields is already done */
+
+			/* check src operand */
+			err = check_reg_arg(env, insn->src_reg, SRC_OP);
+			if (err)
+				return err;
+
+			err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
+			if (err)
+				return err;
+
+			src_reg_type = regs[insn->src_reg].type;
+
+			/* check that memory (src_reg + off) is readable,
+			 * the state of dst_reg will be updated by this func
+			 */
+			err = check_mem_access(env, env->insn_idx, insn->src_reg,
+					       insn->off, BPF_SIZE(insn->code),
+					       BPF_READ, insn->dst_reg, false);
+			if (err)
+				return err;
+
+			prev_src_type = &env->insn_aux_data[env->insn_idx].ptr_type;
+
+			if (*prev_src_type == NOT_INIT) {
+				/* saw a valid insn
+				 * dst_reg = *(u32 *)(src_reg + off)
+				 * save type to validate intersecting paths
+				 */
+				*prev_src_type = src_reg_type;
+
+			} else if (reg_type_mismatch(src_reg_type, *prev_src_type)) {
+				/* ABuser program is trying to use the same insn
+				 * dst_reg = *(u32*) (src_reg + off)
+				 * with different pointer types:
+				 * src_reg == ctx in one branch and
+				 * src_reg == stack|map in some other branch.
+				 * Reject it.
+				 */
+				verbose(env, "same insn cannot be used with different pointers\n");
+				return -EINVAL;
+			}
+
+		} else if (class == BPF_STX) {
+			enum bpf_reg_type *prev_dst_type, dst_reg_type;
+
+			if (BPF_MODE(insn->code) == BPF_ATOMIC) {
+				err = check_atomic(env, env->insn_idx, insn);
+				if (err)
+					return err;
+				env->insn_idx++;
+				continue;
+			}
+
+			if (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0) {
+				verbose(env, "BPF_STX uses reserved fields\n");
+				return -EINVAL;
+			}
+
+			/* check src1 operand */
+			err = check_reg_arg(env, insn->src_reg, SRC_OP);
+			if (err)
+				return err;
+			/* check src2 operand */
+			err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+			if (err)
+				return err;
+
+			dst_reg_type = regs[insn->dst_reg].type;
+
+			/* check that memory (dst_reg + off) is writeable */
+			err = check_mem_access(env, env->insn_idx, insn->dst_reg,
+					       insn->off, BPF_SIZE(insn->code),
+					       BPF_WRITE, insn->src_reg, false);
+			if (err)
+				return err;
+
+			prev_dst_type = &env->insn_aux_data[env->insn_idx].ptr_type;
+
+			if (*prev_dst_type == NOT_INIT) {
+				*prev_dst_type = dst_reg_type;
+			} else if (reg_type_mismatch(dst_reg_type, *prev_dst_type)) {
+				verbose(env, "same insn cannot be used with different pointers\n");
+				return -EINVAL;
+			}
+
+		} else if (class == BPF_ST) {
+			if (BPF_MODE(insn->code) != BPF_MEM ||
+			    insn->src_reg != BPF_REG_0) {
+				verbose(env, "BPF_ST uses reserved fields\n");
+				return -EINVAL;
+			}
+			/* check src operand */
+			err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+			if (err)
+				return err;
+
+			if (is_ctx_reg(env, insn->dst_reg)) {
+				verbose(env, "BPF_ST stores into R%d %s is not allowed\n",
+					insn->dst_reg,
+					reg_type_str(env, reg_state(env, insn->dst_reg)->type));
+				return -EACCES;
+			}
+
+			/* check that memory (dst_reg + off) is writeable */
+			err = check_mem_access(env, env->insn_idx, insn->dst_reg,
+					       insn->off, BPF_SIZE(insn->code),
+					       BPF_WRITE, -1, false);
+			if (err)
+				return err;
+
+		} else if (class == BPF_JMP || class == BPF_JMP32) {
+			u8 opcode = BPF_OP(insn->code);
+
+			env->jmps_processed++;
+			if (opcode == BPF_CALL) {
+				if (BPF_SRC(insn->code) != BPF_K ||
+				    (insn->src_reg != BPF_PSEUDO_KFUNC_CALL
+				     && insn->off != 0) ||
+				    (insn->src_reg != BPF_REG_0 &&
+				     insn->src_reg != BPF_PSEUDO_CALL &&
+				     insn->src_reg != BPF_PSEUDO_KFUNC_CALL) ||
+				    insn->dst_reg != BPF_REG_0 ||
+				    class == BPF_JMP32) {
+					verbose(env, "BPF_CALL uses reserved fields\n");
+					return -EINVAL;
+				}
+
+				if (env->cur_state->active_spin_lock &&
+				    (insn->src_reg == BPF_PSEUDO_CALL ||
+				     insn->imm != BPF_FUNC_spin_unlock)) {
+					verbose(env, "function calls are not allowed while holding a lock\n");
+					return -EINVAL;
+				}
+				if (insn->src_reg == BPF_PSEUDO_CALL)
+					err = check_func_call(env, insn, &env->insn_idx);
+				else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL)
+					err = check_kfunc_call(env, insn, &env->insn_idx);
+				else
+					err = check_helper_call(env, insn, &env->insn_idx);
+				if (err)
+					return err;
+			} else if (opcode == BPF_JA) {
+				if (BPF_SRC(insn->code) != BPF_K ||
+				    insn->src_reg != BPF_REG_0 ||
+				    insn->dst_reg != BPF_REG_0 ||
+				    (class == BPF_JMP && insn->imm != 0) ||
+				    (class == BPF_JMP32 && insn->off != 0)) {
+					verbose(env, "BPF_JA uses reserved fields\n");
+					return -EINVAL;
+				}
+
+				if (class == BPF_JMP)
+					env->insn_idx += insn->off + 1;
+				else
+					env->insn_idx += insn->imm + 1;
+				continue;
+
+			} else if (opcode == BPF_EXIT) {
+				if (BPF_SRC(insn->code) != BPF_K ||
+				    insn->imm != 0 ||
+				    insn->src_reg != BPF_REG_0 ||
+				    insn->dst_reg != BPF_REG_0 ||
+				    class == BPF_JMP32) {
+					verbose(env, "BPF_EXIT uses reserved fields\n");
+					return -EINVAL;
+				}
+
+				if (env->cur_state->active_spin_lock) {
+					verbose(env, "bpf_spin_unlock is missing\n");
+					return -EINVAL;
+				}
+
+				/* We must do check_reference_leak here before
+				 * prepare_func_exit to handle the case when
+				 * state->curframe > 0, it may be a callback
+				 * function, for which reference_state must
+				 * match caller reference state when it exits.
+				 */
+				err = check_reference_leak(env);
+				if (err)
+					return err;
+
+				if (state->curframe) {
+					/* exit from nested function */
+					err = prepare_func_exit(env, &env->insn_idx);
+					if (err)
+						return err;
+					do_print_state = true;
+					continue;
+				}
+
+				err = check_return_code(env);
+				if (err)
+					return err;
+process_bpf_exit:
+				mark_verifier_state_scratched(env);
+				update_branch_counts(env, env->cur_state);
+				err = pop_stack(env, &prev_insn_idx,
+						&env->insn_idx, pop_log);
+				if (err < 0) {
+					if (err != -ENOENT)
+						return err;
+					break;
+				} else {
+					do_print_state = true;
+					continue;
+				}
+			} else {
+				err = check_cond_jmp_op(env, insn, &env->insn_idx);
+				if (err)
+					return err;
+			}
+		} else if (class == BPF_LD) {
+			u8 mode = BPF_MODE(insn->code);
+
+			if (mode == BPF_ABS || mode == BPF_IND) {
+				err = check_ld_abs(env, insn);
+				if (err)
+					return err;
+
+			} else if (mode == BPF_IMM) {
+				err = check_ld_imm(env, insn);
+				if (err)
+					return err;
+
+				env->insn_idx++;
+				sanitize_mark_insn_seen(env);
+			} else {
+				verbose(env, "invalid BPF_LD mode\n");
+				return -EINVAL;
+			}
+		} else {
+			verbose(env, "unknown insn class %d\n", class);
+			return -EINVAL;
+		}
+
+		env->insn_idx++;
+	}
+
+	return 0;
+}
+
+static int find_btf_percpu_datasec(struct btf *btf)
+{
+	const struct btf_type *t;
+	const char *tname;
+	int i, n;
+
+	/*
+	 * Both vmlinux and module each have their own ".data..percpu"
+	 * DATASECs in BTF. So for module's case, we need to skip vmlinux BTF
+	 * types to look at only module's own BTF types.
+	 */
+	n = btf_nr_types(btf);
+	if (btf_is_module(btf))
+		i = btf_nr_types(btf_vmlinux);
+	else
+		i = 1;
+
+	for(; i < n; i++) {
+		t = btf_type_by_id(btf, i);
+		if (BTF_INFO_KIND(t->info) != BTF_KIND_DATASEC)
+			continue;
+
+		tname = btf_name_by_offset(btf, t->name_off);
+		if (!strcmp(tname, ".data..percpu"))
+			return i;
+	}
+
+	return -ENOENT;
+}
+
+/* replace pseudo btf_id with kernel symbol address */
+static int check_pseudo_btf_id(struct bpf_verifier_env *env,
+			       struct bpf_insn *insn,
+			       struct bpf_insn_aux_data *aux)
+{
+	const struct btf_var_secinfo *vsi;
+	const struct btf_type *datasec;
+	struct btf_mod_pair *btf_mod;
+	const struct btf_type *t;
+	const char *sym_name;
+	bool percpu = false;
+	u32 type, id = insn->imm;
+	struct btf *btf;
+	s32 datasec_id;
+	u64 addr;
+	int i, btf_fd, err;
+
+	btf_fd = insn[1].imm;
+	if (btf_fd) {
+		btf = btf_get_by_fd(btf_fd);
+		if (IS_ERR(btf)) {
+			verbose(env, "invalid module BTF object FD specified.\n");
+			return -EINVAL;
+		}
+	} else {
+		if (!btf_vmlinux) {
+			verbose(env, "kernel is missing BTF, make sure CONFIG_DEBUG_INFO_BTF=y is specified in Kconfig.\n");
+			return -EINVAL;
+		}
+		btf = btf_vmlinux;
+		btf_get(btf);
+	}
+
+	t = btf_type_by_id(btf, id);
+	if (!t) {
+		verbose(env, "ldimm64 insn specifies invalid btf_id %d.\n", id);
+		err = -ENOENT;
+		goto err_put;
+	}
+
+	if (!btf_type_is_var(t)) {
+		verbose(env, "pseudo btf_id %d in ldimm64 isn't KIND_VAR.\n", id);
+		err = -EINVAL;
+		goto err_put;
+	}
+
+	sym_name = btf_name_by_offset(btf, t->name_off);
+	addr = kallsyms_lookup_name(sym_name);
+	if (!addr) {
+		verbose(env, "ldimm64 failed to find the address for kernel symbol '%s'.\n",
+			sym_name);
+		err = -ENOENT;
+		goto err_put;
+	}
+
+	datasec_id = find_btf_percpu_datasec(btf);
+	if (datasec_id > 0) {
+		datasec = btf_type_by_id(btf, datasec_id);
+		for_each_vsi(i, datasec, vsi) {
+			if (vsi->type == id) {
+				percpu = true;
+				break;
+			}
+		}
+	}
+
+	insn[0].imm = (u32)addr;
+	insn[1].imm = addr >> 32;
+
+	type = t->type;
+	t = btf_type_skip_modifiers(btf, type, NULL);
+	if (percpu) {
+		aux->btf_var.reg_type = PTR_TO_BTF_ID | MEM_PERCPU;
+		aux->btf_var.btf = btf;
+		aux->btf_var.btf_id = type;
+	} else if (!btf_type_is_struct(t)) {
+		const struct btf_type *ret;
+		const char *tname;
+		u32 tsize;
+
+		/* resolve the type size of ksym. */
+		ret = btf_resolve_size(btf, t, &tsize);
+		if (IS_ERR(ret)) {
+			tname = btf_name_by_offset(btf, t->name_off);
+			verbose(env, "ldimm64 unable to resolve the size of type '%s': %ld\n",
+				tname, PTR_ERR(ret));
+			err = -EINVAL;
+			goto err_put;
+		}
+		aux->btf_var.reg_type = PTR_TO_MEM | MEM_RDONLY;
+		aux->btf_var.mem_size = tsize;
+	} else {
+		aux->btf_var.reg_type = PTR_TO_BTF_ID;
+		aux->btf_var.btf = btf;
+		aux->btf_var.btf_id = type;
+	}
+
+	/* check whether we recorded this BTF (and maybe module) already */
+	for (i = 0; i < env->used_btf_cnt; i++) {
+		if (env->used_btfs[i].btf == btf) {
+			btf_put(btf);
+			return 0;
+		}
+	}
+
+	if (env->used_btf_cnt >= MAX_USED_BTFS) {
+		err = -E2BIG;
+		goto err_put;
+	}
+
+	btf_mod = &env->used_btfs[env->used_btf_cnt];
+	btf_mod->btf = btf;
+	btf_mod->module = NULL;
+
+	/* if we reference variables from kernel module, bump its refcount */
+	if (btf_is_module(btf)) {
+		btf_mod->module = btf_try_get_module(btf);
+		if (!btf_mod->module) {
+			err = -ENXIO;
+			goto err_put;
+		}
+	}
+
+	env->used_btf_cnt++;
+
+	return 0;
+err_put:
+	btf_put(btf);
+	return err;
+}
+
+static bool is_tracing_prog_type(enum bpf_prog_type type)
+{
+	switch (type) {
+	case BPF_PROG_TYPE_KPROBE:
+	case BPF_PROG_TYPE_TRACEPOINT:
+	case BPF_PROG_TYPE_PERF_EVENT:
+	case BPF_PROG_TYPE_RAW_TRACEPOINT:
+	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static int check_map_prog_compatibility(struct bpf_verifier_env *env,
+					struct bpf_map *map,
+					struct bpf_prog *prog)
+
+{
+	enum bpf_prog_type prog_type = resolve_prog_type(prog);
+
+	if (map_value_has_spin_lock(map)) {
+		if (prog_type == BPF_PROG_TYPE_SOCKET_FILTER) {
+			verbose(env, "socket filter progs cannot use bpf_spin_lock yet\n");
+			return -EINVAL;
+		}
+
+		if (is_tracing_prog_type(prog_type)) {
+			verbose(env, "tracing progs cannot use bpf_spin_lock yet\n");
+			return -EINVAL;
+		}
+
+		if (prog->aux->sleepable) {
+			verbose(env, "sleepable progs cannot use bpf_spin_lock yet\n");
+			return -EINVAL;
+		}
+	}
+
+	if (map_value_has_timer(map)) {
+		if (is_tracing_prog_type(prog_type)) {
+			verbose(env, "tracing progs cannot use bpf_timer yet\n");
+			return -EINVAL;
+		}
+	}
+
+	if ((bpf_prog_is_dev_bound(prog->aux) || bpf_map_is_dev_bound(map)) &&
+	    !bpf_offload_prog_map_match(prog, map)) {
+		verbose(env, "offload device mismatch between prog and map\n");
+		return -EINVAL;
+	}
+
+	if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
+		verbose(env, "bpf_struct_ops map cannot be used in prog\n");
+		return -EINVAL;
+	}
+
+	if (prog->aux->sleepable)
+		switch (map->map_type) {
+		case BPF_MAP_TYPE_HASH:
+		case BPF_MAP_TYPE_LRU_HASH:
+		case BPF_MAP_TYPE_ARRAY:
+		case BPF_MAP_TYPE_PERCPU_HASH:
+		case BPF_MAP_TYPE_PERCPU_ARRAY:
+		case BPF_MAP_TYPE_LRU_PERCPU_HASH:
+		case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+		case BPF_MAP_TYPE_HASH_OF_MAPS:
+		case BPF_MAP_TYPE_RINGBUF:
+		case BPF_MAP_TYPE_USER_RINGBUF:
+		case BPF_MAP_TYPE_INODE_STORAGE:
+		case BPF_MAP_TYPE_SK_STORAGE:
+		case BPF_MAP_TYPE_TASK_STORAGE:
+			break;
+		default:
+			verbose(env,
+				"Sleepable programs can only use array, hash, and ringbuf maps\n");
+			return -EINVAL;
+		}
+
+	return 0;
+}
+
+static bool bpf_map_is_cgroup_storage(struct bpf_map *map)
+{
+	return (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE ||
+		map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE);
+}
+
+/* find and rewrite pseudo imm in ld_imm64 instructions:
+ *
+ * 1. if it accesses map FD, replace it with actual map pointer.
+ * 2. if it accesses btf_id of a VAR, replace it with pointer to the var.
+ *
+ * NOTE: btf_vmlinux is required for converting pseudo btf_id.
+ */
+static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
+{
+	struct bpf_insn *insn = env->prog->insnsi;
+	int insn_cnt = env->prog->len;
+	int i, j, err;
+
+	err = bpf_prog_calc_tag(env->prog);
+	if (err)
+		return err;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		if (BPF_CLASS(insn->code) == BPF_LDX &&
+		    (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0)) {
+			verbose(env, "BPF_LDX uses reserved fields\n");
+			return -EINVAL;
+		}
+
+		if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) {
+			struct bpf_insn_aux_data *aux;
+			struct bpf_map *map;
+			struct fd f;
+			u64 addr;
+			u32 fd;
+
+			if (i == insn_cnt - 1 || insn[1].code != 0 ||
+			    insn[1].dst_reg != 0 || insn[1].src_reg != 0 ||
+			    insn[1].off != 0) {
+				verbose(env, "invalid bpf_ld_imm64 insn\n");
+				return -EINVAL;
+			}
+
+			if (insn[0].src_reg == 0)
+				/* valid generic load 64-bit imm */
+				goto next_insn;
+
+			if (insn[0].src_reg == BPF_PSEUDO_BTF_ID) {
+				aux = &env->insn_aux_data[i];
+				err = check_pseudo_btf_id(env, insn, aux);
+				if (err)
+					return err;
+				goto next_insn;
+			}
+
+			if (insn[0].src_reg == BPF_PSEUDO_FUNC) {
+				aux = &env->insn_aux_data[i];
+				aux->ptr_type = PTR_TO_FUNC;
+				goto next_insn;
+			}
+
+			/* In final convert_pseudo_ld_imm64() step, this is
+			 * converted into regular 64-bit imm load insn.
+			 */
+			switch (insn[0].src_reg) {
+			case BPF_PSEUDO_MAP_VALUE:
+			case BPF_PSEUDO_MAP_IDX_VALUE:
+				break;
+			case BPF_PSEUDO_MAP_FD:
+			case BPF_PSEUDO_MAP_IDX:
+				if (insn[1].imm == 0)
+					break;
+				fallthrough;
+			default:
+				verbose(env, "unrecognized bpf_ld_imm64 insn\n");
+				return -EINVAL;
+			}
+
+			switch (insn[0].src_reg) {
+			case BPF_PSEUDO_MAP_IDX_VALUE:
+			case BPF_PSEUDO_MAP_IDX:
+				if (bpfptr_is_null(env->fd_array)) {
+					verbose(env, "fd_idx without fd_array is invalid\n");
+					return -EPROTO;
+				}
+				if (copy_from_bpfptr_offset(&fd, env->fd_array,
+							    insn[0].imm * sizeof(fd),
+							    sizeof(fd)))
+					return -EFAULT;
+				break;
+			default:
+				fd = insn[0].imm;
+				break;
+			}
+
+			f = fdget(fd);
+			map = __bpf_map_get(f);
+			if (IS_ERR(map)) {
+				verbose(env, "fd %d is not pointing to valid bpf_map\n",
+					insn[0].imm);
+				return PTR_ERR(map);
+			}
+
+			err = check_map_prog_compatibility(env, map, env->prog);
+			if (err) {
+				fdput(f);
+				return err;
+			}
+
+			aux = &env->insn_aux_data[i];
+			if (insn[0].src_reg == BPF_PSEUDO_MAP_FD ||
+			    insn[0].src_reg == BPF_PSEUDO_MAP_IDX) {
+				addr = (unsigned long)map;
+			} else {
+				u32 off = insn[1].imm;
+
+				if (off >= BPF_MAX_VAR_OFF) {
+					verbose(env, "direct value offset of %u is not allowed\n", off);
+					fdput(f);
+					return -EINVAL;
+				}
+
+				if (!map->ops->map_direct_value_addr) {
+					verbose(env, "no direct value access support for this map type\n");
+					fdput(f);
+					return -EINVAL;
+				}
+
+				err = map->ops->map_direct_value_addr(map, &addr, off);
+				if (err) {
+					verbose(env, "invalid access to map value pointer, value_size=%u off=%u\n",
+						map->value_size, off);
+					fdput(f);
+					return err;
+				}
+
+				aux->map_off = off;
+				addr += off;
+			}
+
+			insn[0].imm = (u32)addr;
+			insn[1].imm = addr >> 32;
+
+			/* check whether we recorded this map already */
+			for (j = 0; j < env->used_map_cnt; j++) {
+				if (env->used_maps[j] == map) {
+					aux->map_index = j;
+					fdput(f);
+					goto next_insn;
+				}
+			}
+
+			if (env->used_map_cnt >= MAX_USED_MAPS) {
+				fdput(f);
+				return -E2BIG;
+			}
+
+			/* hold the map. If the program is rejected by verifier,
+			 * the map will be released by release_maps() or it
+			 * will be used by the valid program until it's unloaded
+			 * and all maps are released in free_used_maps()
+			 */
+			bpf_map_inc(map);
+
+			aux->map_index = env->used_map_cnt;
+			env->used_maps[env->used_map_cnt++] = map;
+
+			if (bpf_map_is_cgroup_storage(map) &&
+			    bpf_cgroup_storage_assign(env->prog->aux, map)) {
+				verbose(env, "only one cgroup storage of each type is allowed\n");
+				fdput(f);
+				return -EBUSY;
+			}
+
+			fdput(f);
+next_insn:
+			insn++;
+			i++;
+			continue;
+		}
+
+		/* Basic sanity check before we invest more work here. */
+		if (!bpf_opcode_in_insntable(insn->code)) {
+			verbose(env, "unknown opcode %02x\n", insn->code);
+			return -EINVAL;
+		}
+	}
+
+	/* now all pseudo BPF_LD_IMM64 instructions load valid
+	 * 'struct bpf_map *' into a register instead of user map_fd.
+	 * These pointers will be used later by verifier to validate map access.
+	 */
+	return 0;
+}
+
+/* drop refcnt of maps used by the rejected program */
+static void release_maps(struct bpf_verifier_env *env)
+{
+	__bpf_free_used_maps(env->prog->aux, env->used_maps,
+			     env->used_map_cnt);
+}
+
+/* drop refcnt of maps used by the rejected program */
+static void release_btfs(struct bpf_verifier_env *env)
+{
+	__bpf_free_used_btfs(env->prog->aux, env->used_btfs,
+			     env->used_btf_cnt);
+}
+
+/* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */
+static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env)
+{
+	struct bpf_insn *insn = env->prog->insnsi;
+	int insn_cnt = env->prog->len;
+	int i;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		if (insn->code != (BPF_LD | BPF_IMM | BPF_DW))
+			continue;
+		if (insn->src_reg == BPF_PSEUDO_FUNC)
+			continue;
+		insn->src_reg = 0;
+	}
+}
+
+/* single env->prog->insni[off] instruction was replaced with the range
+ * insni[off, off + cnt).  Adjust corresponding insn_aux_data by copying
+ * [0, off) and [off, end) to new locations, so the patched range stays zero
+ */
+static void adjust_insn_aux_data(struct bpf_verifier_env *env,
+				 struct bpf_insn_aux_data *new_data,
+				 struct bpf_prog *new_prog, u32 off, u32 cnt)
+{
+	struct bpf_insn_aux_data *old_data = env->insn_aux_data;
+	struct bpf_insn *insn = new_prog->insnsi;
+	u32 old_seen = old_data[off].seen;
+	u32 prog_len;
+	int i;
+
+	/* aux info at OFF always needs adjustment, no matter fast path
+	 * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the
+	 * original insn at old prog.
+	 */
+	old_data[off].zext_dst = insn_has_def32(env, insn + off + cnt - 1);
+
+	if (cnt == 1)
+		return;
+	prog_len = new_prog->len;
+
+	memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off);
+	memcpy(new_data + off + cnt - 1, old_data + off,
+	       sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1));
+	for (i = off; i < off + cnt - 1; i++) {
+		/* Expand insni[off]'s seen count to the patched range. */
+		new_data[i].seen = old_seen;
+		new_data[i].zext_dst = insn_has_def32(env, insn + i);
+	}
+	env->insn_aux_data = new_data;
+	vfree(old_data);
+}
+
+static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len)
+{
+	int i;
+
+	if (len == 1)
+		return;
+	/* NOTE: fake 'exit' subprog should be updated as well. */
+	for (i = 0; i <= env->subprog_cnt; i++) {
+		if (env->subprog_info[i].start <= off)
+			continue;
+		env->subprog_info[i].start += len - 1;
+	}
+}
+
+static void adjust_poke_descs(struct bpf_prog *prog, u32 off, u32 len)
+{
+	struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
+	int i, sz = prog->aux->size_poke_tab;
+	struct bpf_jit_poke_descriptor *desc;
+
+	for (i = 0; i < sz; i++) {
+		desc = &tab[i];
+		if (desc->insn_idx <= off)
+			continue;
+		desc->insn_idx += len - 1;
+	}
+}
+
+static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off,
+					    const struct bpf_insn *patch, u32 len)
+{
+	struct bpf_prog *new_prog;
+	struct bpf_insn_aux_data *new_data = NULL;
+
+	if (len > 1) {
+		new_data = vzalloc(array_size(env->prog->len + len - 1,
+					      sizeof(struct bpf_insn_aux_data)));
+		if (!new_data)
+			return NULL;
+	}
+
+	new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
+	if (IS_ERR(new_prog)) {
+		if (PTR_ERR(new_prog) == -ERANGE)
+			verbose(env,
+				"insn %d cannot be patched due to 16-bit range\n",
+				env->insn_aux_data[off].orig_idx);
+		vfree(new_data);
+		return NULL;
+	}
+	adjust_insn_aux_data(env, new_data, new_prog, off, len);
+	adjust_subprog_starts(env, off, len);
+	adjust_poke_descs(new_prog, off, len);
+	return new_prog;
+}
+
+static int adjust_subprog_starts_after_remove(struct bpf_verifier_env *env,
+					      u32 off, u32 cnt)
+{
+	int i, j;
+
+	/* find first prog starting at or after off (first to remove) */
+	for (i = 0; i < env->subprog_cnt; i++)
+		if (env->subprog_info[i].start >= off)
+			break;
+	/* find first prog starting at or after off + cnt (first to stay) */
+	for (j = i; j < env->subprog_cnt; j++)
+		if (env->subprog_info[j].start >= off + cnt)
+			break;
+	/* if j doesn't start exactly at off + cnt, we are just removing
+	 * the front of previous prog
+	 */
+	if (env->subprog_info[j].start != off + cnt)
+		j--;
+
+	if (j > i) {
+		struct bpf_prog_aux *aux = env->prog->aux;
+		int move;
+
+		/* move fake 'exit' subprog as well */
+		move = env->subprog_cnt + 1 - j;
+
+		memmove(env->subprog_info + i,
+			env->subprog_info + j,
+			sizeof(*env->subprog_info) * move);
+		env->subprog_cnt -= j - i;
+
+		/* remove func_info */
+		if (aux->func_info) {
+			move = aux->func_info_cnt - j;
+
+			memmove(aux->func_info + i,
+				aux->func_info + j,
+				sizeof(*aux->func_info) * move);
+			aux->func_info_cnt -= j - i;
+			/* func_info->insn_off is set after all code rewrites,
+			 * in adjust_btf_func() - no need to adjust
+			 */
+		}
+	} else {
+		/* convert i from "first prog to remove" to "first to adjust" */
+		if (env->subprog_info[i].start == off)
+			i++;
+	}
+
+	/* update fake 'exit' subprog as well */
+	for (; i <= env->subprog_cnt; i++)
+		env->subprog_info[i].start -= cnt;
+
+	return 0;
+}
+
+static int bpf_adj_linfo_after_remove(struct bpf_verifier_env *env, u32 off,
+				      u32 cnt)
+{
+	struct bpf_prog *prog = env->prog;
+	u32 i, l_off, l_cnt, nr_linfo;
+	struct bpf_line_info *linfo;
+
+	nr_linfo = prog->aux->nr_linfo;
+	if (!nr_linfo)
+		return 0;
+
+	linfo = prog->aux->linfo;
+
+	/* find first line info to remove, count lines to be removed */
+	for (i = 0; i < nr_linfo; i++)
+		if (linfo[i].insn_off >= off)
+			break;
+
+	l_off = i;
+	l_cnt = 0;
+	for (; i < nr_linfo; i++)
+		if (linfo[i].insn_off < off + cnt)
+			l_cnt++;
+		else
+			break;
+
+	/* First live insn doesn't match first live linfo, it needs to "inherit"
+	 * last removed linfo.  prog is already modified, so prog->len == off
+	 * means no live instructions after (tail of the program was removed).
+	 */
+	if (prog->len != off && l_cnt &&
+	    (i == nr_linfo || linfo[i].insn_off != off + cnt)) {
+		l_cnt--;
+		linfo[--i].insn_off = off + cnt;
+	}
+
+	/* remove the line info which refer to the removed instructions */
+	if (l_cnt) {
+		memmove(linfo + l_off, linfo + i,
+			sizeof(*linfo) * (nr_linfo - i));
+
+		prog->aux->nr_linfo -= l_cnt;
+		nr_linfo = prog->aux->nr_linfo;
+	}
+
+	/* pull all linfo[i].insn_off >= off + cnt in by cnt */
+	for (i = l_off; i < nr_linfo; i++)
+		linfo[i].insn_off -= cnt;
+
+	/* fix up all subprogs (incl. 'exit') which start >= off */
+	for (i = 0; i <= env->subprog_cnt; i++)
+		if (env->subprog_info[i].linfo_idx > l_off) {
+			/* program may have started in the removed region but
+			 * may not be fully removed
+			 */
+			if (env->subprog_info[i].linfo_idx >= l_off + l_cnt)
+				env->subprog_info[i].linfo_idx -= l_cnt;
+			else
+				env->subprog_info[i].linfo_idx = l_off;
+		}
+
+	return 0;
+}
+
+static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
+{
+	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+	unsigned int orig_prog_len = env->prog->len;
+	int err;
+
+	if (bpf_prog_is_dev_bound(env->prog->aux))
+		bpf_prog_offload_remove_insns(env, off, cnt);
+
+	err = bpf_remove_insns(env->prog, off, cnt);
+	if (err)
+		return err;
+
+	err = adjust_subprog_starts_after_remove(env, off, cnt);
+	if (err)
+		return err;
+
+	err = bpf_adj_linfo_after_remove(env, off, cnt);
+	if (err)
+		return err;
+
+	memmove(aux_data + off,	aux_data + off + cnt,
+		sizeof(*aux_data) * (orig_prog_len - off - cnt));
+
+	return 0;
+}
+
+/* The verifier does more data flow analysis than llvm and will not
+ * explore branches that are dead at run time. Malicious programs can
+ * have dead code too. Therefore replace all dead at-run-time code
+ * with 'ja -1'.
+ *
+ * Just nops are not optimal, e.g. if they would sit at the end of the
+ * program and through another bug we would manage to jump there, then
+ * we'd execute beyond program memory otherwise. Returning exception
+ * code also wouldn't work since we can have subprogs where the dead
+ * code could be located.
+ */
+static void sanitize_dead_code(struct bpf_verifier_env *env)
+{
+	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+	struct bpf_insn trap = BPF_JMP_IMM(BPF_JA, 0, 0, -1);
+	struct bpf_insn *insn = env->prog->insnsi;
+	const int insn_cnt = env->prog->len;
+	int i;
+
+	for (i = 0; i < insn_cnt; i++) {
+		if (aux_data[i].seen)
+			continue;
+		memcpy(insn + i, &trap, sizeof(trap));
+		aux_data[i].zext_dst = false;
+	}
+}
+
+static bool insn_is_cond_jump(u8 code)
+{
+	u8 op;
+
+	op = BPF_OP(code);
+	if (BPF_CLASS(code) == BPF_JMP32)
+		return op != BPF_JA;
+
+	if (BPF_CLASS(code) != BPF_JMP)
+		return false;
+
+	return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL;
+}
+
+static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env)
+{
+	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+	struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
+	struct bpf_insn *insn = env->prog->insnsi;
+	const int insn_cnt = env->prog->len;
+	int i;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		if (!insn_is_cond_jump(insn->code))
+			continue;
+
+		if (!aux_data[i + 1].seen)
+			ja.off = insn->off;
+		else if (!aux_data[i + 1 + insn->off].seen)
+			ja.off = 0;
+		else
+			continue;
+
+		if (bpf_prog_is_dev_bound(env->prog->aux))
+			bpf_prog_offload_replace_insn(env, i, &ja);
+
+		memcpy(insn, &ja, sizeof(ja));
+	}
+}
+
+static int opt_remove_dead_code(struct bpf_verifier_env *env)
+{
+	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+	int insn_cnt = env->prog->len;
+	int i, err;
+
+	for (i = 0; i < insn_cnt; i++) {
+		int j;
+
+		j = 0;
+		while (i + j < insn_cnt && !aux_data[i + j].seen)
+			j++;
+		if (!j)
+			continue;
+
+		err = verifier_remove_insns(env, i, j);
+		if (err)
+			return err;
+		insn_cnt = env->prog->len;
+	}
+
+	return 0;
+}
+
+static int opt_remove_nops(struct bpf_verifier_env *env)
+{
+	const struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
+	struct bpf_insn *insn = env->prog->insnsi;
+	int insn_cnt = env->prog->len;
+	int i, err;
+
+	for (i = 0; i < insn_cnt; i++) {
+		if (memcmp(&insn[i], &ja, sizeof(ja)))
+			continue;
+
+		err = verifier_remove_insns(env, i, 1);
+		if (err)
+			return err;
+		insn_cnt--;
+		i--;
+	}
+
+	return 0;
+}
+
+static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env,
+					 const union bpf_attr *attr)
+{
+	struct bpf_insn *patch, zext_patch[2], rnd_hi32_patch[4];
+	struct bpf_insn_aux_data *aux = env->insn_aux_data;
+	int i, patch_len, delta = 0, len = env->prog->len;
+	struct bpf_insn *insns = env->prog->insnsi;
+	struct bpf_prog *new_prog;
+	bool rnd_hi32;
+
+	rnd_hi32 = attr->prog_flags & BPF_F_TEST_RND_HI32;
+	zext_patch[1] = BPF_ZEXT_REG(0);
+	rnd_hi32_patch[1] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, 0);
+	rnd_hi32_patch[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
+	rnd_hi32_patch[3] = BPF_ALU64_REG(BPF_OR, 0, BPF_REG_AX);
+	for (i = 0; i < len; i++) {
+		int adj_idx = i + delta;
+		struct bpf_insn insn;
+		int load_reg;
+
+		insn = insns[adj_idx];
+		load_reg = insn_def_regno(&insn);
+		if (!aux[adj_idx].zext_dst) {
+			u8 code, class;
+			u32 imm_rnd;
+
+			if (!rnd_hi32)
+				continue;
+
+			code = insn.code;
+			class = BPF_CLASS(code);
+			if (load_reg == -1)
+				continue;
+
+			/* NOTE: arg "reg" (the fourth one) is only used for
+			 *       BPF_STX + SRC_OP, so it is safe to pass NULL
+			 *       here.
+			 */
+			if (is_reg64(env, &insn, load_reg, NULL, DST_OP)) {
+				if (class == BPF_LD &&
+				    BPF_MODE(code) == BPF_IMM)
+					i++;
+				continue;
+			}
+
+			/* ctx load could be transformed into wider load. */
+			if (class == BPF_LDX &&
+			    aux[adj_idx].ptr_type == PTR_TO_CTX)
+				continue;
+
+			imm_rnd = get_random_u32();
+			rnd_hi32_patch[0] = insn;
+			rnd_hi32_patch[1].imm = imm_rnd;
+			rnd_hi32_patch[3].dst_reg = load_reg;
+			patch = rnd_hi32_patch;
+			patch_len = 4;
+			goto apply_patch_buffer;
+		}
+
+		/* Add in an zero-extend instruction if a) the JIT has requested
+		 * it or b) it's a CMPXCHG.
+		 *
+		 * The latter is because: BPF_CMPXCHG always loads a value into
+		 * R0, therefore always zero-extends. However some archs'
+		 * equivalent instruction only does this load when the
+		 * comparison is successful. This detail of CMPXCHG is
+		 * orthogonal to the general zero-extension behaviour of the
+		 * CPU, so it's treated independently of bpf_jit_needs_zext.
+		 */
+		if (!bpf_jit_needs_zext() && !is_cmpxchg_insn(&insn))
+			continue;
+
+		/* Zero-extension is done by the caller. */
+		if (bpf_pseudo_kfunc_call(&insn))
+			continue;
+
+		if (WARN_ON(load_reg == -1)) {
+			verbose(env, "verifier bug. zext_dst is set, but no reg is defined\n");
+			return -EFAULT;
+		}
+
+		zext_patch[0] = insn;
+		zext_patch[1].dst_reg = load_reg;
+		zext_patch[1].src_reg = load_reg;
+		patch = zext_patch;
+		patch_len = 2;
+apply_patch_buffer:
+		new_prog = bpf_patch_insn_data(env, adj_idx, patch, patch_len);
+		if (!new_prog)
+			return -ENOMEM;
+		env->prog = new_prog;
+		insns = new_prog->insnsi;
+		aux = env->insn_aux_data;
+		delta += patch_len - 1;
+	}
+
+	return 0;
+}
+
+/* convert load instructions that access fields of a context type into a
+ * sequence of instructions that access fields of the underlying structure:
+ *     struct __sk_buff    -> struct sk_buff
+ *     struct bpf_sock_ops -> struct sock
+ */
+static int convert_ctx_accesses(struct bpf_verifier_env *env)
+{
+	const struct bpf_verifier_ops *ops = env->ops;
+	int i, cnt, size, ctx_field_size, delta = 0;
+	const int insn_cnt = env->prog->len;
+	struct bpf_insn insn_buf[16], *insn;
+	u32 target_size, size_default, off;
+	struct bpf_prog *new_prog;
+	enum bpf_access_type type;
+	bool is_narrower_load;
+
+	if (ops->gen_prologue || env->seen_direct_write) {
+		if (!ops->gen_prologue) {
+			verbose(env, "bpf verifier is misconfigured\n");
+			return -EINVAL;
+		}
+		cnt = ops->gen_prologue(insn_buf, env->seen_direct_write,
+					env->prog);
+		if (cnt >= ARRAY_SIZE(insn_buf)) {
+			verbose(env, "bpf verifier is misconfigured\n");
+			return -EINVAL;
+		} else if (cnt) {
+			new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			env->prog = new_prog;
+			delta += cnt - 1;
+		}
+	}
+
+	if (bpf_prog_is_dev_bound(env->prog->aux))
+		return 0;
+
+	insn = env->prog->insnsi + delta;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		bpf_convert_ctx_access_t convert_ctx_access;
+		bool ctx_access;
+
+		if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) ||
+		    insn->code == (BPF_LDX | BPF_MEM | BPF_H) ||
+		    insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
+		    insn->code == (BPF_LDX | BPF_MEM | BPF_DW)) {
+			type = BPF_READ;
+			ctx_access = true;
+		} else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) ||
+			   insn->code == (BPF_STX | BPF_MEM | BPF_H) ||
+			   insn->code == (BPF_STX | BPF_MEM | BPF_W) ||
+			   insn->code == (BPF_STX | BPF_MEM | BPF_DW) ||
+			   insn->code == (BPF_ST | BPF_MEM | BPF_B) ||
+			   insn->code == (BPF_ST | BPF_MEM | BPF_H) ||
+			   insn->code == (BPF_ST | BPF_MEM | BPF_W) ||
+			   insn->code == (BPF_ST | BPF_MEM | BPF_DW)) {
+			type = BPF_WRITE;
+			ctx_access = BPF_CLASS(insn->code) == BPF_STX;
+		} else {
+			continue;
+		}
+
+		if (type == BPF_WRITE &&
+		    env->insn_aux_data[i + delta].sanitize_stack_spill) {
+			struct bpf_insn patch[] = {
+				*insn,
+				BPF_ST_NOSPEC(),
+			};
+
+			cnt = ARRAY_SIZE(patch);
+			new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta    += cnt - 1;
+			env->prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+		if (!ctx_access)
+			continue;
+
+		switch ((int)env->insn_aux_data[i + delta].ptr_type) {
+		case PTR_TO_CTX:
+			if (!ops->convert_ctx_access)
+				continue;
+			convert_ctx_access = ops->convert_ctx_access;
+			break;
+		case PTR_TO_SOCKET:
+		case PTR_TO_SOCK_COMMON:
+			convert_ctx_access = bpf_sock_convert_ctx_access;
+			break;
+		case PTR_TO_TCP_SOCK:
+			convert_ctx_access = bpf_tcp_sock_convert_ctx_access;
+			break;
+		case PTR_TO_XDP_SOCK:
+			convert_ctx_access = bpf_xdp_sock_convert_ctx_access;
+			break;
+		case PTR_TO_BTF_ID:
+		case PTR_TO_BTF_ID | PTR_UNTRUSTED:
+			if (type == BPF_READ) {
+				insn->code = BPF_LDX | BPF_PROBE_MEM |
+					BPF_SIZE((insn)->code);
+				env->prog->aux->num_exentries++;
+			}
+			continue;
+		default:
+			continue;
+		}
+
+		ctx_field_size = env->insn_aux_data[i + delta].ctx_field_size;
+		size = BPF_LDST_BYTES(insn);
+
+		/* If the read access is a narrower load of the field,
+		 * convert to a 4/8-byte load, to minimum program type specific
+		 * convert_ctx_access changes. If conversion is successful,
+		 * we will apply proper mask to the result.
+		 */
+		is_narrower_load = size < ctx_field_size;
+		size_default = bpf_ctx_off_adjust_machine(ctx_field_size);
+		off = insn->off;
+		if (is_narrower_load) {
+			u8 size_code;
+
+			if (type == BPF_WRITE) {
+				verbose(env, "bpf verifier narrow ctx access misconfigured\n");
+				return -EINVAL;
+			}
+
+			size_code = BPF_H;
+			if (ctx_field_size == 4)
+				size_code = BPF_W;
+			else if (ctx_field_size == 8)
+				size_code = BPF_DW;
+
+			insn->off = off & ~(size_default - 1);
+			insn->code = BPF_LDX | BPF_MEM | size_code;
+		}
+
+		target_size = 0;
+		cnt = convert_ctx_access(type, insn, insn_buf, env->prog,
+					 &target_size);
+		if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) ||
+		    (ctx_field_size && !target_size)) {
+			verbose(env, "bpf verifier is misconfigured\n");
+			return -EINVAL;
+		}
+
+		if (is_narrower_load && size < target_size) {
+			u8 shift = bpf_ctx_narrow_access_offset(
+				off, size, size_default) * 8;
+			if (shift && cnt + 1 >= ARRAY_SIZE(insn_buf)) {
+				verbose(env, "bpf verifier narrow ctx load misconfigured\n");
+				return -EINVAL;
+			}
+			if (ctx_field_size <= 4) {
+				if (shift)
+					insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH,
+									insn->dst_reg,
+									shift);
+				insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
+								(1 << size * 8) - 1);
+			} else {
+				if (shift)
+					insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH,
+									insn->dst_reg,
+									shift);
+				insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
+								(1ULL << size * 8) - 1);
+			}
+		}
+
+		new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+		if (!new_prog)
+			return -ENOMEM;
+
+		delta += cnt - 1;
+
+		/* keep walking new program and skip insns we just inserted */
+		env->prog = new_prog;
+		insn      = new_prog->insnsi + i + delta;
+	}
+
+	return 0;
+}
+
+static int jit_subprogs(struct bpf_verifier_env *env)
+{
+	struct bpf_prog *prog = env->prog, **func, *tmp;
+	int i, j, subprog_start, subprog_end = 0, len, subprog;
+	struct bpf_map *map_ptr;
+	struct bpf_insn *insn;
+	void *old_bpf_func;
+	int err, num_exentries;
+
+	if (env->subprog_cnt <= 1)
+		return 0;
+
+	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
+		if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn))
+			continue;
+
+		/* Upon error here we cannot fall back to interpreter but
+		 * need a hard reject of the program. Thus -EFAULT is
+		 * propagated in any case.
+		 */
+		subprog = find_subprog(env, i + insn->imm + 1);
+		if (subprog < 0) {
+			WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
+				  i + insn->imm + 1);
+			return -EFAULT;
+		}
+		/* temporarily remember subprog id inside insn instead of
+		 * aux_data, since next loop will split up all insns into funcs
+		 */
+		insn->off = subprog;
+		/* remember original imm in case JIT fails and fallback
+		 * to interpreter will be needed
+		 */
+		env->insn_aux_data[i].call_imm = insn->imm;
+		/* point imm to __bpf_call_base+1 from JITs point of view */
+		insn->imm = 1;
+		if (bpf_pseudo_func(insn))
+			/* jit (e.g. x86_64) may emit fewer instructions
+			 * if it learns a u32 imm is the same as a u64 imm.
+			 * Force a non zero here.
+			 */
+			insn[1].imm = 1;
+	}
+
+	err = bpf_prog_alloc_jited_linfo(prog);
+	if (err)
+		goto out_undo_insn;
+
+	err = -ENOMEM;
+	func = kcalloc(env->subprog_cnt, sizeof(prog), GFP_KERNEL);
+	if (!func)
+		goto out_undo_insn;
+
+	for (i = 0; i < env->subprog_cnt; i++) {
+		subprog_start = subprog_end;
+		subprog_end = env->subprog_info[i + 1].start;
+
+		len = subprog_end - subprog_start;
+		/* bpf_prog_run() doesn't call subprogs directly,
+		 * hence main prog stats include the runtime of subprogs.
+		 * subprogs don't have IDs and not reachable via prog_get_next_id
+		 * func[i]->stats will never be accessed and stays NULL
+		 */
+		func[i] = bpf_prog_alloc_no_stats(bpf_prog_size(len), GFP_USER);
+		if (!func[i])
+			goto out_free;
+		memcpy(func[i]->insnsi, &prog->insnsi[subprog_start],
+		       len * sizeof(struct bpf_insn));
+		func[i]->type = prog->type;
+		func[i]->len = len;
+		if (bpf_prog_calc_tag(func[i]))
+			goto out_free;
+		func[i]->is_func = 1;
+		func[i]->aux->func_idx = i;
+		/* Below members will be freed only at prog->aux */
+		func[i]->aux->btf = prog->aux->btf;
+		func[i]->aux->func_info = prog->aux->func_info;
+		func[i]->aux->func_info_cnt = prog->aux->func_info_cnt;
+		func[i]->aux->poke_tab = prog->aux->poke_tab;
+		func[i]->aux->size_poke_tab = prog->aux->size_poke_tab;
+
+		for (j = 0; j < prog->aux->size_poke_tab; j++) {
+			struct bpf_jit_poke_descriptor *poke;
+
+			poke = &prog->aux->poke_tab[j];
+			if (poke->insn_idx < subprog_end &&
+			    poke->insn_idx >= subprog_start)
+				poke->aux = func[i]->aux;
+		}
+
+		func[i]->aux->name[0] = 'F';
+		func[i]->aux->stack_depth = env->subprog_info[i].stack_depth;
+		func[i]->jit_requested = 1;
+		func[i]->blinding_requested = prog->blinding_requested;
+		func[i]->aux->kfunc_tab = prog->aux->kfunc_tab;
+		func[i]->aux->kfunc_btf_tab = prog->aux->kfunc_btf_tab;
+		func[i]->aux->linfo = prog->aux->linfo;
+		func[i]->aux->nr_linfo = prog->aux->nr_linfo;
+		func[i]->aux->jited_linfo = prog->aux->jited_linfo;
+		func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx;
+		num_exentries = 0;
+		insn = func[i]->insnsi;
+		for (j = 0; j < func[i]->len; j++, insn++) {
+			if (BPF_CLASS(insn->code) == BPF_LDX &&
+			    BPF_MODE(insn->code) == BPF_PROBE_MEM)
+				num_exentries++;
+		}
+		func[i]->aux->num_exentries = num_exentries;
+		func[i]->aux->tail_call_reachable = env->subprog_info[i].tail_call_reachable;
+		func[i] = bpf_int_jit_compile(func[i]);
+		if (!func[i]->jited) {
+			err = -ENOTSUPP;
+			goto out_free;
+		}
+		cond_resched();
+	}
+
+	/* at this point all bpf functions were successfully JITed
+	 * now populate all bpf_calls with correct addresses and
+	 * run last pass of JIT
+	 */
+	for (i = 0; i < env->subprog_cnt; i++) {
+		insn = func[i]->insnsi;
+		for (j = 0; j < func[i]->len; j++, insn++) {
+			if (bpf_pseudo_func(insn)) {
+				subprog = insn->off;
+				insn[0].imm = (u32)(long)func[subprog]->bpf_func;
+				insn[1].imm = ((u64)(long)func[subprog]->bpf_func) >> 32;
+				continue;
+			}
+			if (!bpf_pseudo_call(insn))
+				continue;
+			subprog = insn->off;
+			insn->imm = BPF_CALL_IMM(func[subprog]->bpf_func);
+		}
+
+		/* we use the aux data to keep a list of the start addresses
+		 * of the JITed images for each function in the program
+		 *
+		 * for some architectures, such as powerpc64, the imm field
+		 * might not be large enough to hold the offset of the start
+		 * address of the callee's JITed image from __bpf_call_base
+		 *
+		 * in such cases, we can lookup the start address of a callee
+		 * by using its subprog id, available from the off field of
+		 * the call instruction, as an index for this list
+		 */
+		func[i]->aux->func = func;
+		func[i]->aux->func_cnt = env->subprog_cnt;
+	}
+	for (i = 0; i < env->subprog_cnt; i++) {
+		old_bpf_func = func[i]->bpf_func;
+		tmp = bpf_int_jit_compile(func[i]);
+		if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) {
+			verbose(env, "JIT doesn't support bpf-to-bpf calls\n");
+			err = -ENOTSUPP;
+			goto out_free;
+		}
+		cond_resched();
+	}
+
+	/* finally lock prog and jit images for all functions and
+	 * populate kallsysm. Begin at the first subprogram, since
+	 * bpf_prog_load will add the kallsyms for the main program.
+	 */
+	for (i = 1; i < env->subprog_cnt; i++) {
+		bpf_prog_lock_ro(func[i]);
+		bpf_prog_kallsyms_add(func[i]);
+	}
+
+	/* Last step: make now unused interpreter insns from main
+	 * prog consistent for later dump requests, so they can
+	 * later look the same as if they were interpreted only.
+	 */
+	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
+		if (bpf_pseudo_func(insn)) {
+			insn[0].imm = env->insn_aux_data[i].call_imm;
+			insn[1].imm = insn->off;
+			insn->off = 0;
+			continue;
+		}
+		if (!bpf_pseudo_call(insn))
+			continue;
+		insn->off = env->insn_aux_data[i].call_imm;
+		subprog = find_subprog(env, i + insn->off + 1);
+		insn->imm = subprog;
+	}
+
+	prog->jited = 1;
+	prog->bpf_func = func[0]->bpf_func;
+	prog->jited_len = func[0]->jited_len;
+	prog->aux->extable = func[0]->aux->extable;
+	prog->aux->num_exentries = func[0]->aux->num_exentries;
+	prog->aux->func = func;
+	prog->aux->func_cnt = env->subprog_cnt;
+	bpf_prog_jit_attempt_done(prog);
+	return 0;
+out_free:
+	/* We failed JIT'ing, so at this point we need to unregister poke
+	 * descriptors from subprogs, so that kernel is not attempting to
+	 * patch it anymore as we're freeing the subprog JIT memory.
+	 */
+	for (i = 0; i < prog->aux->size_poke_tab; i++) {
+		map_ptr = prog->aux->poke_tab[i].tail_call.map;
+		map_ptr->ops->map_poke_untrack(map_ptr, prog->aux);
+	}
+	/* At this point we're guaranteed that poke descriptors are not
+	 * live anymore. We can just unlink its descriptor table as it's
+	 * released with the main prog.
+	 */
+	for (i = 0; i < env->subprog_cnt; i++) {
+		if (!func[i])
+			continue;
+		func[i]->aux->poke_tab = NULL;
+		bpf_jit_free(func[i]);
+	}
+	kfree(func);
+out_undo_insn:
+	/* cleanup main prog to be interpreted */
+	prog->jit_requested = 0;
+	prog->blinding_requested = 0;
+	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
+		if (!bpf_pseudo_call(insn))
+			continue;
+		insn->off = 0;
+		insn->imm = env->insn_aux_data[i].call_imm;
+	}
+	bpf_prog_jit_attempt_done(prog);
+	return err;
+}
+
+static int fixup_call_args(struct bpf_verifier_env *env)
+{
+#ifndef CONFIG_BPF_JIT_ALWAYS_ON
+	struct bpf_prog *prog = env->prog;
+	struct bpf_insn *insn = prog->insnsi;
+	bool has_kfunc_call = bpf_prog_has_kfunc_call(prog);
+	int i, depth;
+#endif
+	int err = 0;
+
+	if (env->prog->jit_requested &&
+	    !bpf_prog_is_dev_bound(env->prog->aux)) {
+		err = jit_subprogs(env);
+		if (err == 0)
+			return 0;
+		if (err == -EFAULT)
+			return err;
+	}
+#ifndef CONFIG_BPF_JIT_ALWAYS_ON
+	if (has_kfunc_call) {
+		verbose(env, "calling kernel functions are not allowed in non-JITed programs\n");
+		return -EINVAL;
+	}
+	if (env->subprog_cnt > 1 && env->prog->aux->tail_call_reachable) {
+		/* When JIT fails the progs with bpf2bpf calls and tail_calls
+		 * have to be rejected, since interpreter doesn't support them yet.
+		 */
+		verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
+		return -EINVAL;
+	}
+	for (i = 0; i < prog->len; i++, insn++) {
+		if (bpf_pseudo_func(insn)) {
+			/* When JIT fails the progs with callback calls
+			 * have to be rejected, since interpreter doesn't support them yet.
+			 */
+			verbose(env, "callbacks are not allowed in non-JITed programs\n");
+			return -EINVAL;
+		}
+
+		if (!bpf_pseudo_call(insn))
+			continue;
+		depth = get_callee_stack_depth(env, insn, i);
+		if (depth < 0)
+			return depth;
+		bpf_patch_call_args(insn, depth);
+	}
+	err = 0;
+#endif
+	return err;
+}
+
+static int fixup_kfunc_call(struct bpf_verifier_env *env,
+			    struct bpf_insn *insn)
+{
+	const struct bpf_kfunc_desc *desc;
+
+	if (!insn->imm) {
+		verbose(env, "invalid kernel function call not eliminated in verifier pass\n");
+		return -EINVAL;
+	}
+
+	/* insn->imm has the btf func_id. Replace it with
+	 * an address (relative to __bpf_base_call).
+	 */
+	desc = find_kfunc_desc(env->prog, insn->imm, insn->off);
+	if (!desc) {
+		verbose(env, "verifier internal error: kernel function descriptor not found for func_id %u\n",
+			insn->imm);
+		return -EFAULT;
+	}
+
+	insn->imm = desc->imm;
+
+	return 0;
+}
+
+/* Do various post-verification rewrites in a single program pass.
+ * These rewrites simplify JIT and interpreter implementations.
+ */
+static int do_misc_fixups(struct bpf_verifier_env *env)
+{
+	struct bpf_prog *prog = env->prog;
+	enum bpf_attach_type eatype = prog->expected_attach_type;
+	enum bpf_prog_type prog_type = resolve_prog_type(prog);
+	struct bpf_insn *insn = prog->insnsi;
+	const struct bpf_func_proto *fn;
+	const int insn_cnt = prog->len;
+	const struct bpf_map_ops *ops;
+	struct bpf_insn_aux_data *aux;
+	struct bpf_insn insn_buf[16];
+	struct bpf_prog *new_prog;
+	struct bpf_map *map_ptr;
+	int i, ret, cnt, delta = 0;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		/* Make divide-by-zero exceptions impossible. */
+		if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) ||
+		    insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) ||
+		    insn->code == (BPF_ALU | BPF_MOD | BPF_X) ||
+		    insn->code == (BPF_ALU | BPF_DIV | BPF_X)) {
+			bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
+			bool isdiv = BPF_OP(insn->code) == BPF_DIV;
+			struct bpf_insn *patchlet;
+			struct bpf_insn chk_and_div[] = {
+				/* [R,W]x div 0 -> 0 */
+				BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
+					     BPF_JNE | BPF_K, insn->src_reg,
+					     0, 2, 0),
+				BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg),
+				BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+				*insn,
+			};
+			struct bpf_insn chk_and_mod[] = {
+				/* [R,W]x mod 0 -> [R,W]x */
+				BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
+					     BPF_JEQ | BPF_K, insn->src_reg,
+					     0, 1 + (is64 ? 0 : 1), 0),
+				*insn,
+				BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+				BPF_MOV32_REG(insn->dst_reg, insn->dst_reg),
+			};
+
+			patchlet = isdiv ? chk_and_div : chk_and_mod;
+			cnt = isdiv ? ARRAY_SIZE(chk_and_div) :
+				      ARRAY_SIZE(chk_and_mod) - (is64 ? 2 : 0);
+
+			new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta    += cnt - 1;
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+		/* Implement LD_ABS and LD_IND with a rewrite, if supported by the program type. */
+		if (BPF_CLASS(insn->code) == BPF_LD &&
+		    (BPF_MODE(insn->code) == BPF_ABS ||
+		     BPF_MODE(insn->code) == BPF_IND)) {
+			cnt = env->ops->gen_ld_abs(insn, insn_buf);
+			if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) {
+				verbose(env, "bpf verifier is misconfigured\n");
+				return -EINVAL;
+			}
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta    += cnt - 1;
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+		/* Rewrite pointer arithmetic to mitigate speculation attacks. */
+		if (insn->code == (BPF_ALU64 | BPF_ADD | BPF_X) ||
+		    insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) {
+			const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X;
+			const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X;
+			struct bpf_insn *patch = &insn_buf[0];
+			bool issrc, isneg, isimm;
+			u32 off_reg;
+
+			aux = &env->insn_aux_data[i + delta];
+			if (!aux->alu_state ||
+			    aux->alu_state == BPF_ALU_NON_POINTER)
+				continue;
+
+			isneg = aux->alu_state & BPF_ALU_NEG_VALUE;
+			issrc = (aux->alu_state & BPF_ALU_SANITIZE) ==
+				BPF_ALU_SANITIZE_SRC;
+			isimm = aux->alu_state & BPF_ALU_IMMEDIATE;
+
+			off_reg = issrc ? insn->src_reg : insn->dst_reg;
+			if (isimm) {
+				*patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
+			} else {
+				if (isneg)
+					*patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
+				*patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
+				*patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
+				*patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
+				*patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
+				*patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
+				*patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX, off_reg);
+			}
+			if (!issrc)
+				*patch++ = BPF_MOV64_REG(insn->dst_reg, insn->src_reg);
+			insn->src_reg = BPF_REG_AX;
+			if (isneg)
+				insn->code = insn->code == code_add ?
+					     code_sub : code_add;
+			*patch++ = *insn;
+			if (issrc && isneg && !isimm)
+				*patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
+			cnt = patch - insn_buf;
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta    += cnt - 1;
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+		if (insn->code != (BPF_JMP | BPF_CALL))
+			continue;
+		if (insn->src_reg == BPF_PSEUDO_CALL)
+			continue;
+		if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
+			ret = fixup_kfunc_call(env, insn);
+			if (ret)
+				return ret;
+			continue;
+		}
+
+		if (insn->imm == BPF_FUNC_get_route_realm)
+			prog->dst_needed = 1;
+		if (insn->imm == BPF_FUNC_get_prandom_u32)
+			bpf_user_rnd_init_once();
+		if (insn->imm == BPF_FUNC_override_return)
+			prog->kprobe_override = 1;
+		if (insn->imm == BPF_FUNC_tail_call) {
+			/* If we tail call into other programs, we
+			 * cannot make any assumptions since they can
+			 * be replaced dynamically during runtime in
+			 * the program array.
+			 */
+			prog->cb_access = 1;
+			if (!allow_tail_call_in_subprogs(env))
+				prog->aux->stack_depth = MAX_BPF_STACK;
+			prog->aux->max_pkt_offset = MAX_PACKET_OFF;
+
+			/* mark bpf_tail_call as different opcode to avoid
+			 * conditional branch in the interpreter for every normal
+			 * call and to prevent accidental JITing by JIT compiler
+			 * that doesn't support bpf_tail_call yet
+			 */
+			insn->imm = 0;
+			insn->code = BPF_JMP | BPF_TAIL_CALL;
+
+			aux = &env->insn_aux_data[i + delta];
+			if (env->bpf_capable && !prog->blinding_requested &&
+			    prog->jit_requested &&
+			    !bpf_map_key_poisoned(aux) &&
+			    !bpf_map_ptr_poisoned(aux) &&
+			    !bpf_map_ptr_unpriv(aux)) {
+				struct bpf_jit_poke_descriptor desc = {
+					.reason = BPF_POKE_REASON_TAIL_CALL,
+					.tail_call.map = BPF_MAP_PTR(aux->map_ptr_state),
+					.tail_call.key = bpf_map_key_immediate(aux),
+					.insn_idx = i + delta,
+				};
+
+				ret = bpf_jit_add_poke_descriptor(prog, &desc);
+				if (ret < 0) {
+					verbose(env, "adding tail call poke descriptor failed\n");
+					return ret;
+				}
+
+				insn->imm = ret + 1;
+				continue;
+			}
+
+			if (!bpf_map_ptr_unpriv(aux))
+				continue;
+
+			/* instead of changing every JIT dealing with tail_call
+			 * emit two extra insns:
+			 * if (index >= max_entries) goto out;
+			 * index &= array->index_mask;
+			 * to avoid out-of-bounds cpu speculation
+			 */
+			if (bpf_map_ptr_poisoned(aux)) {
+				verbose(env, "tail_call abusing map_ptr\n");
+				return -EINVAL;
+			}
+
+			map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
+			insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3,
+						  map_ptr->max_entries, 2);
+			insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3,
+						    container_of(map_ptr,
+								 struct bpf_array,
+								 map)->index_mask);
+			insn_buf[2] = *insn;
+			cnt = 3;
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta    += cnt - 1;
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+		if (insn->imm == BPF_FUNC_timer_set_callback) {
+			/* The verifier will process callback_fn as many times as necessary
+			 * with different maps and the register states prepared by
+			 * set_timer_callback_state will be accurate.
+			 *
+			 * The following use case is valid:
+			 *   map1 is shared by prog1, prog2, prog3.
+			 *   prog1 calls bpf_timer_init for some map1 elements
+			 *   prog2 calls bpf_timer_set_callback for some map1 elements.
+			 *     Those that were not bpf_timer_init-ed will return -EINVAL.
+			 *   prog3 calls bpf_timer_start for some map1 elements.
+			 *     Those that were not both bpf_timer_init-ed and
+			 *     bpf_timer_set_callback-ed will return -EINVAL.
+			 */
+			struct bpf_insn ld_addrs[2] = {
+				BPF_LD_IMM64(BPF_REG_3, (long)prog->aux),
+			};
+
+			insn_buf[0] = ld_addrs[0];
+			insn_buf[1] = ld_addrs[1];
+			insn_buf[2] = *insn;
+			cnt = 3;
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta    += cnt - 1;
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			goto patch_call_imm;
+		}
+
+		if (insn->imm == BPF_FUNC_task_storage_get ||
+		    insn->imm == BPF_FUNC_sk_storage_get ||
+		    insn->imm == BPF_FUNC_inode_storage_get) {
+			if (env->prog->aux->sleepable)
+				insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_KERNEL);
+			else
+				insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_ATOMIC);
+			insn_buf[1] = *insn;
+			cnt = 2;
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta += cnt - 1;
+			env->prog = prog = new_prog;
+			insn = new_prog->insnsi + i + delta;
+			goto patch_call_imm;
+		}
+
+		/* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup
+		 * and other inlining handlers are currently limited to 64 bit
+		 * only.
+		 */
+		if (prog->jit_requested && BITS_PER_LONG == 64 &&
+		    (insn->imm == BPF_FUNC_map_lookup_elem ||
+		     insn->imm == BPF_FUNC_map_update_elem ||
+		     insn->imm == BPF_FUNC_map_delete_elem ||
+		     insn->imm == BPF_FUNC_map_push_elem   ||
+		     insn->imm == BPF_FUNC_map_pop_elem    ||
+		     insn->imm == BPF_FUNC_map_peek_elem   ||
+		     insn->imm == BPF_FUNC_redirect_map    ||
+		     insn->imm == BPF_FUNC_for_each_map_elem ||
+		     insn->imm == BPF_FUNC_map_lookup_percpu_elem)) {
+			aux = &env->insn_aux_data[i + delta];
+			if (bpf_map_ptr_poisoned(aux))
+				goto patch_call_imm;
+
+			map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
+			ops = map_ptr->ops;
+			if (insn->imm == BPF_FUNC_map_lookup_elem &&
+			    ops->map_gen_lookup) {
+				cnt = ops->map_gen_lookup(map_ptr, insn_buf);
+				if (cnt == -EOPNOTSUPP)
+					goto patch_map_ops_generic;
+				if (cnt <= 0 || cnt >= ARRAY_SIZE(insn_buf)) {
+					verbose(env, "bpf verifier is misconfigured\n");
+					return -EINVAL;
+				}
+
+				new_prog = bpf_patch_insn_data(env, i + delta,
+							       insn_buf, cnt);
+				if (!new_prog)
+					return -ENOMEM;
+
+				delta    += cnt - 1;
+				env->prog = prog = new_prog;
+				insn      = new_prog->insnsi + i + delta;
+				continue;
+			}
+
+			BUILD_BUG_ON(!__same_type(ops->map_lookup_elem,
+				     (void *(*)(struct bpf_map *map, void *key))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_delete_elem,
+				     (int (*)(struct bpf_map *map, void *key))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_update_elem,
+				     (int (*)(struct bpf_map *map, void *key, void *value,
+					      u64 flags))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_push_elem,
+				     (int (*)(struct bpf_map *map, void *value,
+					      u64 flags))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_pop_elem,
+				     (int (*)(struct bpf_map *map, void *value))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_peek_elem,
+				     (int (*)(struct bpf_map *map, void *value))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_redirect,
+				     (int (*)(struct bpf_map *map, u32 ifindex, u64 flags))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_for_each_callback,
+				     (int (*)(struct bpf_map *map,
+					      bpf_callback_t callback_fn,
+					      void *callback_ctx,
+					      u64 flags))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_lookup_percpu_elem,
+				     (void *(*)(struct bpf_map *map, void *key, u32 cpu))NULL));
+
+patch_map_ops_generic:
+			switch (insn->imm) {
+			case BPF_FUNC_map_lookup_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_lookup_elem);
+				continue;
+			case BPF_FUNC_map_update_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_update_elem);
+				continue;
+			case BPF_FUNC_map_delete_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_delete_elem);
+				continue;
+			case BPF_FUNC_map_push_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_push_elem);
+				continue;
+			case BPF_FUNC_map_pop_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_pop_elem);
+				continue;
+			case BPF_FUNC_map_peek_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_peek_elem);
+				continue;
+			case BPF_FUNC_redirect_map:
+				insn->imm = BPF_CALL_IMM(ops->map_redirect);
+				continue;
+			case BPF_FUNC_for_each_map_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_for_each_callback);
+				continue;
+			case BPF_FUNC_map_lookup_percpu_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_lookup_percpu_elem);
+				continue;
+			}
+
+			goto patch_call_imm;
+		}
+
+		/* Implement bpf_jiffies64 inline. */
+		if (prog->jit_requested && BITS_PER_LONG == 64 &&
+		    insn->imm == BPF_FUNC_jiffies64) {
+			struct bpf_insn ld_jiffies_addr[2] = {
+				BPF_LD_IMM64(BPF_REG_0,
+					     (unsigned long)&jiffies),
+			};
+
+			insn_buf[0] = ld_jiffies_addr[0];
+			insn_buf[1] = ld_jiffies_addr[1];
+			insn_buf[2] = BPF_LDX_MEM(BPF_DW, BPF_REG_0,
+						  BPF_REG_0, 0);
+			cnt = 3;
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf,
+						       cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta    += cnt - 1;
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+		/* Implement bpf_get_func_arg inline. */
+		if (prog_type == BPF_PROG_TYPE_TRACING &&
+		    insn->imm == BPF_FUNC_get_func_arg) {
+			/* Load nr_args from ctx - 8 */
+			insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
+			insn_buf[1] = BPF_JMP32_REG(BPF_JGE, BPF_REG_2, BPF_REG_0, 6);
+			insn_buf[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_2, 3);
+			insn_buf[3] = BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_1);
+			insn_buf[4] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 0);
+			insn_buf[5] = BPF_STX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0);
+			insn_buf[6] = BPF_MOV64_IMM(BPF_REG_0, 0);
+			insn_buf[7] = BPF_JMP_A(1);
+			insn_buf[8] = BPF_MOV64_IMM(BPF_REG_0, -EINVAL);
+			cnt = 9;
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta    += cnt - 1;
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+		/* Implement bpf_get_func_ret inline. */
+		if (prog_type == BPF_PROG_TYPE_TRACING &&
+		    insn->imm == BPF_FUNC_get_func_ret) {
+			if (eatype == BPF_TRACE_FEXIT ||
+			    eatype == BPF_MODIFY_RETURN) {
+				/* Load nr_args from ctx - 8 */
+				insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
+				insn_buf[1] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_0, 3);
+				insn_buf[2] = BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1);
+				insn_buf[3] = BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0);
+				insn_buf[4] = BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_3, 0);
+				insn_buf[5] = BPF_MOV64_IMM(BPF_REG_0, 0);
+				cnt = 6;
+			} else {
+				insn_buf[0] = BPF_MOV64_IMM(BPF_REG_0, -EOPNOTSUPP);
+				cnt = 1;
+			}
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta    += cnt - 1;
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+		/* Implement get_func_arg_cnt inline. */
+		if (prog_type == BPF_PROG_TYPE_TRACING &&
+		    insn->imm == BPF_FUNC_get_func_arg_cnt) {
+			/* Load nr_args from ctx - 8 */
+			insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, 1);
+			if (!new_prog)
+				return -ENOMEM;
+
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+		/* Implement bpf_get_func_ip inline. */
+		if (prog_type == BPF_PROG_TYPE_TRACING &&
+		    insn->imm == BPF_FUNC_get_func_ip) {
+			/* Load IP address from ctx - 16 */
+			insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -16);
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, 1);
+			if (!new_prog)
+				return -ENOMEM;
+
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+patch_call_imm:
+		fn = env->ops->get_func_proto(insn->imm, env->prog);
+		/* all functions that have prototype and verifier allowed
+		 * programs to call them, must be real in-kernel functions
+		 */
+		if (!fn->func) {
+			verbose(env,
+				"kernel subsystem misconfigured func %s#%d\n",
+				func_id_name(insn->imm), insn->imm);
+			return -EFAULT;
+		}
+		insn->imm = fn->func - __bpf_call_base;
+	}
+
+	/* Since poke tab is now finalized, publish aux to tracker. */
+	for (i = 0; i < prog->aux->size_poke_tab; i++) {
+		map_ptr = prog->aux->poke_tab[i].tail_call.map;
+		if (!map_ptr->ops->map_poke_track ||
+		    !map_ptr->ops->map_poke_untrack ||
+		    !map_ptr->ops->map_poke_run) {
+			verbose(env, "bpf verifier is misconfigured\n");
+			return -EINVAL;
+		}
+
+		ret = map_ptr->ops->map_poke_track(map_ptr, prog->aux);
+		if (ret < 0) {
+			verbose(env, "tracking tail call prog failed\n");
+			return ret;
+		}
+	}
+
+	sort_kfunc_descs_by_imm(env->prog);
+
+	return 0;
+}
+
+static struct bpf_prog *inline_bpf_loop(struct bpf_verifier_env *env,
+					int position,
+					s32 stack_base,
+					u32 callback_subprogno,
+					u32 *cnt)
+{
+	s32 r6_offset = stack_base + 0 * BPF_REG_SIZE;
+	s32 r7_offset = stack_base + 1 * BPF_REG_SIZE;
+	s32 r8_offset = stack_base + 2 * BPF_REG_SIZE;
+	int reg_loop_max = BPF_REG_6;
+	int reg_loop_cnt = BPF_REG_7;
+	int reg_loop_ctx = BPF_REG_8;
+
+	struct bpf_prog *new_prog;
+	u32 callback_start;
+	u32 call_insn_offset;
+	s32 callback_offset;
+
+	/* This represents an inlined version of bpf_iter.c:bpf_loop,
+	 * be careful to modify this code in sync.
+	 */
+	struct bpf_insn insn_buf[] = {
+		/* Return error and jump to the end of the patch if
+		 * expected number of iterations is too big.
+		 */
+		BPF_JMP_IMM(BPF_JLE, BPF_REG_1, BPF_MAX_LOOPS, 2),
+		BPF_MOV32_IMM(BPF_REG_0, -E2BIG),
+		BPF_JMP_IMM(BPF_JA, 0, 0, 16),
+		/* spill R6, R7, R8 to use these as loop vars */
+		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, r6_offset),
+		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_7, r7_offset),
+		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_8, r8_offset),
+		/* initialize loop vars */
+		BPF_MOV64_REG(reg_loop_max, BPF_REG_1),
+		BPF_MOV32_IMM(reg_loop_cnt, 0),
+		BPF_MOV64_REG(reg_loop_ctx, BPF_REG_3),
+		/* loop header,
+		 * if reg_loop_cnt >= reg_loop_max skip the loop body
+		 */
+		BPF_JMP_REG(BPF_JGE, reg_loop_cnt, reg_loop_max, 5),
+		/* callback call,
+		 * correct callback offset would be set after patching
+		 */
+		BPF_MOV64_REG(BPF_REG_1, reg_loop_cnt),
+		BPF_MOV64_REG(BPF_REG_2, reg_loop_ctx),
+		BPF_CALL_REL(0),
+		/* increment loop counter */
+		BPF_ALU64_IMM(BPF_ADD, reg_loop_cnt, 1),
+		/* jump to loop header if callback returned 0 */
+		BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, -6),
+		/* return value of bpf_loop,
+		 * set R0 to the number of iterations
+		 */
+		BPF_MOV64_REG(BPF_REG_0, reg_loop_cnt),
+		/* restore original values of R6, R7, R8 */
+		BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, r6_offset),
+		BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_10, r7_offset),
+		BPF_LDX_MEM(BPF_DW, BPF_REG_8, BPF_REG_10, r8_offset),
+	};
+
+	*cnt = ARRAY_SIZE(insn_buf);
+	new_prog = bpf_patch_insn_data(env, position, insn_buf, *cnt);
+	if (!new_prog)
+		return new_prog;
+
+	/* callback start is known only after patching */
+	callback_start = env->subprog_info[callback_subprogno].start;
+	/* Note: insn_buf[12] is an offset of BPF_CALL_REL instruction */
+	call_insn_offset = position + 12;
+	callback_offset = callback_start - call_insn_offset - 1;
+	new_prog->insnsi[call_insn_offset].imm = callback_offset;
+
+	return new_prog;
+}
+
+static bool is_bpf_loop_call(struct bpf_insn *insn)
+{
+	return insn->code == (BPF_JMP | BPF_CALL) &&
+		insn->src_reg == 0 &&
+		insn->imm == BPF_FUNC_loop;
+}
+
+/* For all sub-programs in the program (including main) check
+ * insn_aux_data to see if there are bpf_loop calls that require
+ * inlining. If such calls are found the calls are replaced with a
+ * sequence of instructions produced by `inline_bpf_loop` function and
+ * subprog stack_depth is increased by the size of 3 registers.
+ * This stack space is used to spill values of the R6, R7, R8.  These
+ * registers are used to store the loop bound, counter and context
+ * variables.
+ */
+static int optimize_bpf_loop(struct bpf_verifier_env *env)
+{
+	struct bpf_subprog_info *subprogs = env->subprog_info;
+	int i, cur_subprog = 0, cnt, delta = 0;
+	struct bpf_insn *insn = env->prog->insnsi;
+	int insn_cnt = env->prog->len;
+	u16 stack_depth = subprogs[cur_subprog].stack_depth;
+	u16 stack_depth_roundup = round_up(stack_depth, 8) - stack_depth;
+	u16 stack_depth_extra = 0;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		struct bpf_loop_inline_state *inline_state =
+			&env->insn_aux_data[i + delta].loop_inline_state;
+
+		if (is_bpf_loop_call(insn) && inline_state->fit_for_inline) {
+			struct bpf_prog *new_prog;
+
+			stack_depth_extra = BPF_REG_SIZE * 3 + stack_depth_roundup;
+			new_prog = inline_bpf_loop(env,
+						   i + delta,
+						   -(stack_depth + stack_depth_extra),
+						   inline_state->callback_subprogno,
+						   &cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta     += cnt - 1;
+			env->prog  = new_prog;
+			insn       = new_prog->insnsi + i + delta;
+		}
+
+		if (subprogs[cur_subprog + 1].start == i + delta + 1) {
+			subprogs[cur_subprog].stack_depth += stack_depth_extra;
+			cur_subprog++;
+			stack_depth = subprogs[cur_subprog].stack_depth;
+			stack_depth_roundup = round_up(stack_depth, 8) - stack_depth;
+			stack_depth_extra = 0;
+		}
+	}
+
+	env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
+
+	return 0;
+}
+
+static void free_states(struct bpf_verifier_env *env)
+{
+	struct bpf_verifier_state_list *sl, *sln;
+	int i;
+
+	sl = env->free_list;
+	while (sl) {
+		sln = sl->next;
+		free_verifier_state(&sl->state, false);
+		kfree(sl);
+		sl = sln;
+	}
+	env->free_list = NULL;
+
+	if (!env->explored_states)
+		return;
+
+	for (i = 0; i < state_htab_size(env); i++) {
+		sl = env->explored_states[i];
+
+		while (sl) {
+			sln = sl->next;
+			free_verifier_state(&sl->state, false);
+			kfree(sl);
+			sl = sln;
+		}
+		env->explored_states[i] = NULL;
+	}
+}
+
+static int do_check_common(struct bpf_verifier_env *env, int subprog)
+{
+	bool pop_log = !(env->log.level & BPF_LOG_LEVEL2);
+	struct bpf_verifier_state *state;
+	struct bpf_reg_state *regs;
+	int ret, i;
+
+	env->prev_linfo = NULL;
+	env->pass_cnt++;
+
+	state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+	state->curframe = 0;
+	state->speculative = false;
+	state->branches = 1;
+	state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL);
+	if (!state->frame[0]) {
+		kfree(state);
+		return -ENOMEM;
+	}
+	env->cur_state = state;
+	init_func_state(env, state->frame[0],
+			BPF_MAIN_FUNC /* callsite */,
+			0 /* frameno */,
+			subprog);
+	state->first_insn_idx = env->subprog_info[subprog].start;
+	state->last_insn_idx = -1;
+
+	regs = state->frame[state->curframe]->regs;
+	if (subprog || env->prog->type == BPF_PROG_TYPE_EXT) {
+		ret = btf_prepare_func_args(env, subprog, regs);
+		if (ret)
+			goto out;
+		for (i = BPF_REG_1; i <= BPF_REG_5; i++) {
+			if (regs[i].type == PTR_TO_CTX)
+				mark_reg_known_zero(env, regs, i);
+			else if (regs[i].type == SCALAR_VALUE)
+				mark_reg_unknown(env, regs, i);
+			else if (base_type(regs[i].type) == PTR_TO_MEM) {
+				const u32 mem_size = regs[i].mem_size;
+
+				mark_reg_known_zero(env, regs, i);
+				regs[i].mem_size = mem_size;
+				regs[i].id = ++env->id_gen;
+			}
+		}
+	} else {
+		/* 1st arg to a function */
+		regs[BPF_REG_1].type = PTR_TO_CTX;
+		mark_reg_known_zero(env, regs, BPF_REG_1);
+		ret = btf_check_subprog_arg_match(env, subprog, regs);
+		if (ret == -EFAULT)
+			/* unlikely verifier bug. abort.
+			 * ret == 0 and ret < 0 are sadly acceptable for
+			 * main() function due to backward compatibility.
+			 * Like socket filter program may be written as:
+			 * int bpf_prog(struct pt_regs *ctx)
+			 * and never dereference that ctx in the program.
+			 * 'struct pt_regs' is a type mismatch for socket
+			 * filter that should be using 'struct __sk_buff'.
+			 */
+			goto out;
+	}
+
+	ret = do_check(env);
+out:
+	/* check for NULL is necessary, since cur_state can be freed inside
+	 * do_check() under memory pressure.
+	 */
+	if (env->cur_state) {
+		free_verifier_state(env->cur_state, true);
+		env->cur_state = NULL;
+	}
+	while (!pop_stack(env, NULL, NULL, false));
+	if (!ret && pop_log)
+		bpf_vlog_reset(&env->log, 0);
+	free_states(env);
+	return ret;
+}
+
+/* Verify all global functions in a BPF program one by one based on their BTF.
+ * All global functions must pass verification. Otherwise the whole program is rejected.
+ * Consider:
+ * int bar(int);
+ * int foo(int f)
+ * {
+ *    return bar(f);
+ * }
+ * int bar(int b)
+ * {
+ *    ...
+ * }
+ * foo() will be verified first for R1=any_scalar_value. During verification it
+ * will be assumed that bar() already verified successfully and call to bar()
+ * from foo() will be checked for type match only. Later bar() will be verified
+ * independently to check that it's safe for R1=any_scalar_value.
+ */
+static int do_check_subprogs(struct bpf_verifier_env *env)
+{
+	struct bpf_prog_aux *aux = env->prog->aux;
+	int i, ret;
+
+	if (!aux->func_info)
+		return 0;
+
+	for (i = 1; i < env->subprog_cnt; i++) {
+		if (aux->func_info_aux[i].linkage != BTF_FUNC_GLOBAL)
+			continue;
+		env->insn_idx = env->subprog_info[i].start;
+		WARN_ON_ONCE(env->insn_idx == 0);
+		ret = do_check_common(env, i);
+		if (ret) {
+			return ret;
+		} else if (env->log.level & BPF_LOG_LEVEL) {
+			verbose(env,
+				"Func#%d is safe for any args that match its prototype\n",
+				i);
+		}
+	}
+	return 0;
+}
+
+static int do_check_main(struct bpf_verifier_env *env)
+{
+	int ret;
+
+	env->insn_idx = 0;
+	ret = do_check_common(env, 0);
+	if (!ret)
+		env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
+	return ret;
+}
+
+
+static void print_verification_stats(struct bpf_verifier_env *env)
+{
+	int i;
+
+	if (env->log.level & BPF_LOG_STATS) {
+		verbose(env, "verification time %lld usec\n",
+			div_u64(env->verification_time, 1000));
+		verbose(env, "stack depth ");
+		for (i = 0; i < env->subprog_cnt; i++) {
+			u32 depth = env->subprog_info[i].stack_depth;
+
+			verbose(env, "%d", depth);
+			if (i + 1 < env->subprog_cnt)
+				verbose(env, "+");
+		}
+		verbose(env, "\n");
+	}
+	verbose(env, "processed %d insns (limit %d) max_states_per_insn %d "
+		"total_states %d peak_states %d mark_read %d\n",
+		env->insn_processed, BPF_COMPLEXITY_LIMIT_INSNS,
+		env->max_states_per_insn, env->total_states,
+		env->peak_states, env->longest_mark_read_walk);
+}
+
+static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
+{
+	const struct btf_type *t, *func_proto;
+	const struct bpf_struct_ops *st_ops;
+	const struct btf_member *member;
+	struct bpf_prog *prog = env->prog;
+	u32 btf_id, member_idx;
+	const char *mname;
+
+	if (!prog->gpl_compatible) {
+		verbose(env, "struct ops programs must have a GPL compatible license\n");
+		return -EINVAL;
+	}
+
+	btf_id = prog->aux->attach_btf_id;
+	st_ops = bpf_struct_ops_find(btf_id);
+	if (!st_ops) {
+		verbose(env, "attach_btf_id %u is not a supported struct\n",
+			btf_id);
+		return -ENOTSUPP;
+	}
+
+	t = st_ops->type;
+	member_idx = prog->expected_attach_type;
+	if (member_idx >= btf_type_vlen(t)) {
+		verbose(env, "attach to invalid member idx %u of struct %s\n",
+			member_idx, st_ops->name);
+		return -EINVAL;
+	}
+
+	member = &btf_type_member(t)[member_idx];
+	mname = btf_name_by_offset(btf_vmlinux, member->name_off);
+	func_proto = btf_type_resolve_func_ptr(btf_vmlinux, member->type,
+					       NULL);
+	if (!func_proto) {
+		verbose(env, "attach to invalid member %s(@idx %u) of struct %s\n",
+			mname, member_idx, st_ops->name);
+		return -EINVAL;
+	}
+
+	if (st_ops->check_member) {
+		int err = st_ops->check_member(t, member);
+
+		if (err) {
+			verbose(env, "attach to unsupported member %s of struct %s\n",
+				mname, st_ops->name);
+			return err;
+		}
+	}
+
+	prog->aux->attach_func_proto = func_proto;
+	prog->aux->attach_func_name = mname;
+	env->ops = st_ops->verifier_ops;
+
+	return 0;
+}
+#define SECURITY_PREFIX "security_"
+
+static int check_attach_modify_return(unsigned long addr, const char *func_name)
+{
+	if (within_error_injection_list(addr) ||
+	    !strncmp(SECURITY_PREFIX, func_name, sizeof(SECURITY_PREFIX) - 1))
+		return 0;
+
+	return -EINVAL;
+}
+
+/* list of non-sleepable functions that are otherwise on
+ * ALLOW_ERROR_INJECTION list
+ */
+BTF_SET_START(btf_non_sleepable_error_inject)
+/* Three functions below can be called from sleepable and non-sleepable context.
+ * Assume non-sleepable from bpf safety point of view.
+ */
+BTF_ID(func, __filemap_add_folio)
+BTF_ID(func, should_fail_alloc_page)
+BTF_ID(func, should_failslab)
+BTF_SET_END(btf_non_sleepable_error_inject)
+
+static int check_non_sleepable_error_inject(u32 btf_id)
+{
+	return btf_id_set_contains(&btf_non_sleepable_error_inject, btf_id);
+}
+
+int bpf_check_attach_target(struct bpf_verifier_log *log,
+			    const struct bpf_prog *prog,
+			    const struct bpf_prog *tgt_prog,
+			    u32 btf_id,
+			    struct bpf_attach_target_info *tgt_info)
+{
+	bool prog_extension = prog->type == BPF_PROG_TYPE_EXT;
+	const char prefix[] = "btf_trace_";
+	int ret = 0, subprog = -1, i;
+	const struct btf_type *t;
+	bool conservative = true;
+	const char *tname;
+	struct btf *btf;
+	long addr = 0;
+
+	if (!btf_id) {
+		bpf_log(log, "Tracing programs must provide btf_id\n");
+		return -EINVAL;
+	}
+	btf = tgt_prog ? tgt_prog->aux->btf : prog->aux->attach_btf;
+	if (!btf) {
+		bpf_log(log,
+			"FENTRY/FEXIT program can only be attached to another program annotated with BTF\n");
+		return -EINVAL;
+	}
+	t = btf_type_by_id(btf, btf_id);
+	if (!t) {
+		bpf_log(log, "attach_btf_id %u is invalid\n", btf_id);
+		return -EINVAL;
+	}
+	tname = btf_name_by_offset(btf, t->name_off);
+	if (!tname) {
+		bpf_log(log, "attach_btf_id %u doesn't have a name\n", btf_id);
+		return -EINVAL;
+	}
+	if (tgt_prog) {
+		struct bpf_prog_aux *aux = tgt_prog->aux;
+
+		for (i = 0; i < aux->func_info_cnt; i++)
+			if (aux->func_info[i].type_id == btf_id) {
+				subprog = i;
+				break;
+			}
+		if (subprog == -1) {
+			bpf_log(log, "Subprog %s doesn't exist\n", tname);
+			return -EINVAL;
+		}
+		conservative = aux->func_info_aux[subprog].unreliable;
+		if (prog_extension) {
+			if (conservative) {
+				bpf_log(log,
+					"Cannot replace static functions\n");
+				return -EINVAL;
+			}
+			if (!prog->jit_requested) {
+				bpf_log(log,
+					"Extension programs should be JITed\n");
+				return -EINVAL;
+			}
+		}
+		if (!tgt_prog->jited) {
+			bpf_log(log, "Can attach to only JITed progs\n");
+			return -EINVAL;
+		}
+		if (tgt_prog->type == prog->type) {
+			/* Cannot fentry/fexit another fentry/fexit program.
+			 * Cannot attach program extension to another extension.
+			 * It's ok to attach fentry/fexit to extension program.
+			 */
+			bpf_log(log, "Cannot recursively attach\n");
+			return -EINVAL;
+		}
+		if (tgt_prog->type == BPF_PROG_TYPE_TRACING &&
+		    prog_extension &&
+		    (tgt_prog->expected_attach_type == BPF_TRACE_FENTRY ||
+		     tgt_prog->expected_attach_type == BPF_TRACE_FEXIT)) {
+			/* Program extensions can extend all program types
+			 * except fentry/fexit. The reason is the following.
+			 * The fentry/fexit programs are used for performance
+			 * analysis, stats and can be attached to any program
+			 * type except themselves. When extension program is
+			 * replacing XDP function it is necessary to allow
+			 * performance analysis of all functions. Both original
+			 * XDP program and its program extension. Hence
+			 * attaching fentry/fexit to BPF_PROG_TYPE_EXT is
+			 * allowed. If extending of fentry/fexit was allowed it
+			 * would be possible to create long call chain
+			 * fentry->extension->fentry->extension beyond
+			 * reasonable stack size. Hence extending fentry is not
+			 * allowed.
+			 */
+			bpf_log(log, "Cannot extend fentry/fexit\n");
+			return -EINVAL;
+		}
+	} else {
+		if (prog_extension) {
+			bpf_log(log, "Cannot replace kernel functions\n");
+			return -EINVAL;
+		}
+	}
+
+	switch (prog->expected_attach_type) {
+	case BPF_TRACE_RAW_TP:
+		if (tgt_prog) {
+			bpf_log(log,
+				"Only FENTRY/FEXIT progs are attachable to another BPF prog\n");
+			return -EINVAL;
+		}
+		if (!btf_type_is_typedef(t)) {
+			bpf_log(log, "attach_btf_id %u is not a typedef\n",
+				btf_id);
+			return -EINVAL;
+		}
+		if (strncmp(prefix, tname, sizeof(prefix) - 1)) {
+			bpf_log(log, "attach_btf_id %u points to wrong type name %s\n",
+				btf_id, tname);
+			return -EINVAL;
+		}
+		tname += sizeof(prefix) - 1;
+		t = btf_type_by_id(btf, t->type);
+		if (!btf_type_is_ptr(t))
+			/* should never happen in valid vmlinux build */
+			return -EINVAL;
+		t = btf_type_by_id(btf, t->type);
+		if (!btf_type_is_func_proto(t))
+			/* should never happen in valid vmlinux build */
+			return -EINVAL;
+
+		break;
+	case BPF_TRACE_ITER:
+		if (!btf_type_is_func(t)) {
+			bpf_log(log, "attach_btf_id %u is not a function\n",
+				btf_id);
+			return -EINVAL;
+		}
+		t = btf_type_by_id(btf, t->type);
+		if (!btf_type_is_func_proto(t))
+			return -EINVAL;
+		ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel);
+		if (ret)
+			return ret;
+		break;
+	default:
+		if (!prog_extension)
+			return -EINVAL;
+		fallthrough;
+	case BPF_MODIFY_RETURN:
+	case BPF_LSM_MAC:
+	case BPF_LSM_CGROUP:
+	case BPF_TRACE_FENTRY:
+	case BPF_TRACE_FEXIT:
+		if (!btf_type_is_func(t)) {
+			bpf_log(log, "attach_btf_id %u is not a function\n",
+				btf_id);
+			return -EINVAL;
+		}
+		if (prog_extension &&
+		    btf_check_type_match(log, prog, btf, t))
+			return -EINVAL;
+		t = btf_type_by_id(btf, t->type);
+		if (!btf_type_is_func_proto(t))
+			return -EINVAL;
+
+		if ((prog->aux->saved_dst_prog_type || prog->aux->saved_dst_attach_type) &&
+		    (!tgt_prog || prog->aux->saved_dst_prog_type != tgt_prog->type ||
+		     prog->aux->saved_dst_attach_type != tgt_prog->expected_attach_type))
+			return -EINVAL;
+
+		if (tgt_prog && conservative)
+			t = NULL;
+
+		ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel);
+		if (ret < 0)
+			return ret;
+
+		if (tgt_prog) {
+			if (subprog == 0)
+				addr = (long) tgt_prog->bpf_func;
+			else
+				addr = (long) tgt_prog->aux->func[subprog]->bpf_func;
+		} else {
+			addr = kallsyms_lookup_name(tname);
+			if (!addr) {
+				bpf_log(log,
+					"The address of function %s cannot be found\n",
+					tname);
+				return -ENOENT;
+			}
+		}
+
+		if (prog->aux->sleepable) {
+			ret = -EINVAL;
+			switch (prog->type) {
+			case BPF_PROG_TYPE_TRACING:
+				/* fentry/fexit/fmod_ret progs can be sleepable only if they are
+				 * attached to ALLOW_ERROR_INJECTION and are not in denylist.
+				 */
+				if (!check_non_sleepable_error_inject(btf_id) &&
+				    within_error_injection_list(addr))
+					ret = 0;
+				break;
+			case BPF_PROG_TYPE_LSM:
+				/* LSM progs check that they are attached to bpf_lsm_*() funcs.
+				 * Only some of them are sleepable.
+				 */
+				if (bpf_lsm_is_sleepable_hook(btf_id))
+					ret = 0;
+				break;
+			default:
+				break;
+			}
+			if (ret) {
+				bpf_log(log, "%s is not sleepable\n", tname);
+				return ret;
+			}
+		} else if (prog->expected_attach_type == BPF_MODIFY_RETURN) {
+			if (tgt_prog) {
+				bpf_log(log, "can't modify return codes of BPF programs\n");
+				return -EINVAL;
+			}
+			ret = check_attach_modify_return(addr, tname);
+			if (ret) {
+				bpf_log(log, "%s() is not modifiable\n", tname);
+				return ret;
+			}
+		}
+
+		break;
+	}
+	tgt_info->tgt_addr = addr;
+	tgt_info->tgt_name = tname;
+	tgt_info->tgt_type = t;
+	return 0;
+}
+
+BTF_SET_START(btf_id_deny)
+BTF_ID_UNUSED
+#ifdef CONFIG_SMP
+BTF_ID(func, migrate_disable)
+BTF_ID(func, migrate_enable)
+#endif
+#if !defined CONFIG_PREEMPT_RCU && !defined CONFIG_TINY_RCU
+BTF_ID(func, rcu_read_unlock_strict)
+#endif
+#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_TRACE_PREEMPT_TOGGLE)
+BTF_ID(func, preempt_count_add)
+BTF_ID(func, preempt_count_sub)
+#endif
+BTF_SET_END(btf_id_deny)
+
+static int check_attach_btf_id(struct bpf_verifier_env *env)
+{
+	struct bpf_prog *prog = env->prog;
+	struct bpf_prog *tgt_prog = prog->aux->dst_prog;
+	struct bpf_attach_target_info tgt_info = {};
+	u32 btf_id = prog->aux->attach_btf_id;
+	struct bpf_trampoline *tr;
+	int ret;
+	u64 key;
+
+	if (prog->type == BPF_PROG_TYPE_SYSCALL) {
+		if (prog->aux->sleepable)
+			/* attach_btf_id checked to be zero already */
+			return 0;
+		verbose(env, "Syscall programs can only be sleepable\n");
+		return -EINVAL;
+	}
+
+	if (prog->aux->sleepable && prog->type != BPF_PROG_TYPE_TRACING &&
+	    prog->type != BPF_PROG_TYPE_LSM && prog->type != BPF_PROG_TYPE_KPROBE) {
+		verbose(env, "Only fentry/fexit/fmod_ret, lsm, and kprobe/uprobe programs can be sleepable\n");
+		return -EINVAL;
+	}
+
+	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS)
+		return check_struct_ops_btf_id(env);
+
+	if (prog->type != BPF_PROG_TYPE_TRACING &&
+	    prog->type != BPF_PROG_TYPE_LSM &&
+	    prog->type != BPF_PROG_TYPE_EXT)
+		return 0;
+
+	ret = bpf_check_attach_target(&env->log, prog, tgt_prog, btf_id, &tgt_info);
+	if (ret)
+		return ret;
+
+	if (tgt_prog && prog->type == BPF_PROG_TYPE_EXT) {
+		/* to make freplace equivalent to their targets, they need to
+		 * inherit env->ops and expected_attach_type for the rest of the
+		 * verification
+		 */
+		env->ops = bpf_verifier_ops[tgt_prog->type];
+		prog->expected_attach_type = tgt_prog->expected_attach_type;
+	}
+
+	/* store info about the attachment target that will be used later */
+	prog->aux->attach_func_proto = tgt_info.tgt_type;
+	prog->aux->attach_func_name = tgt_info.tgt_name;
+
+	if (tgt_prog) {
+		prog->aux->saved_dst_prog_type = tgt_prog->type;
+		prog->aux->saved_dst_attach_type = tgt_prog->expected_attach_type;
+	}
+
+	if (prog->expected_attach_type == BPF_TRACE_RAW_TP) {
+		prog->aux->attach_btf_trace = true;
+		return 0;
+	} else if (prog->expected_attach_type == BPF_TRACE_ITER) {
+		if (!bpf_iter_prog_supported(prog))
+			return -EINVAL;
+		return 0;
+	}
+
+	if (prog->type == BPF_PROG_TYPE_LSM) {
+		ret = bpf_lsm_verify_prog(&env->log, prog);
+		if (ret < 0)
+			return ret;
+	} else if (prog->type == BPF_PROG_TYPE_TRACING &&
+		   btf_id_set_contains(&btf_id_deny, btf_id)) {
+		return -EINVAL;
+	}
+
+	key = bpf_trampoline_compute_key(tgt_prog, prog->aux->attach_btf, btf_id);
+	tr = bpf_trampoline_get(key, &tgt_info);
+	if (!tr)
+		return -ENOMEM;
+
+	if (tgt_prog && tgt_prog->aux->tail_call_reachable)
+		tr->flags = BPF_TRAMP_F_TAIL_CALL_CTX;
+
+	prog->aux->dst_trampoline = tr;
+	return 0;
+}
+
+struct btf *bpf_get_btf_vmlinux(void)
+{
+	if (!btf_vmlinux && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
+		mutex_lock(&bpf_verifier_lock);
+		if (!btf_vmlinux)
+			btf_vmlinux = btf_parse_vmlinux();
+		mutex_unlock(&bpf_verifier_lock);
+	}
+	return btf_vmlinux;
+}
+
+int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr)
+{
+	u64 start_time = ktime_get_ns();
+	struct bpf_verifier_env *env;
+	struct bpf_verifier_log *log;
+	int i, len, ret = -EINVAL;
+	bool is_priv;
+
+	/* no program is valid */
+	if (ARRAY_SIZE(bpf_verifier_ops) == 0)
+		return -EINVAL;
+
+	/* 'struct bpf_verifier_env' can be global, but since it's not small,
+	 * allocate/free it every time bpf_check() is called
+	 */
+	env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL);
+	if (!env)
+		return -ENOMEM;
+	log = &env->log;
+
+	len = (*prog)->len;
+	env->insn_aux_data =
+		vzalloc(array_size(sizeof(struct bpf_insn_aux_data), len));
+	ret = -ENOMEM;
+	if (!env->insn_aux_data)
+		goto err_free_env;
+	for (i = 0; i < len; i++)
+		env->insn_aux_data[i].orig_idx = i;
+	env->prog = *prog;
+	env->ops = bpf_verifier_ops[env->prog->type];
+	env->fd_array = make_bpfptr(attr->fd_array, uattr.is_kernel);
+	is_priv = bpf_capable();
+
+	bpf_get_btf_vmlinux();
+
+	/* grab the mutex to protect few globals used by verifier */
+	if (!is_priv)
+		mutex_lock(&bpf_verifier_lock);
+
+	if (attr->log_level || attr->log_buf || attr->log_size) {
+		/* user requested verbose verifier output
+		 * and supplied buffer to store the verification trace
+		 */
+		log->level = attr->log_level;
+		log->ubuf = (char __user *) (unsigned long) attr->log_buf;
+		log->len_total = attr->log_size;
+
+		/* log attributes have to be sane */
+		if (!bpf_verifier_log_attr_valid(log)) {
+			ret = -EINVAL;
+			goto err_unlock;
+		}
+	}
+
+	mark_verifier_state_clean(env);
+
+	if (IS_ERR(btf_vmlinux)) {
+		/* Either gcc or pahole or kernel are broken. */
+		verbose(env, "in-kernel BTF is malformed\n");
+		ret = PTR_ERR(btf_vmlinux);
+		goto skip_full_check;
+	}
+
+	env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT);
+	if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
+		env->strict_alignment = true;
+	if (attr->prog_flags & BPF_F_ANY_ALIGNMENT)
+		env->strict_alignment = false;
+
+	env->allow_ptr_leaks = bpf_allow_ptr_leaks();
+	env->allow_uninit_stack = bpf_allow_uninit_stack();
+	env->allow_ptr_to_map_access = bpf_allow_ptr_to_map_access();
+	env->bypass_spec_v1 = bpf_bypass_spec_v1();
+	env->bypass_spec_v4 = bpf_bypass_spec_v4();
+	env->bpf_capable = bpf_capable();
+
+	if (is_priv)
+		env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
+
+	env->explored_states = kvcalloc(state_htab_size(env),
+				       sizeof(struct bpf_verifier_state_list *),
+				       GFP_USER);
+	ret = -ENOMEM;
+	if (!env->explored_states)
+		goto skip_full_check;
+
+	ret = add_subprog_and_kfunc(env);
+	if (ret < 0)
+		goto skip_full_check;
+
+	ret = check_subprogs(env);
+	if (ret < 0)
+		goto skip_full_check;
+
+	ret = check_btf_info(env, attr, uattr);
+	if (ret < 0)
+		goto skip_full_check;
+
+	ret = check_attach_btf_id(env);
+	if (ret)
+		goto skip_full_check;
+
+	ret = resolve_pseudo_ldimm64(env);
+	if (ret < 0)
+		goto skip_full_check;
+
+	if (bpf_prog_is_dev_bound(env->prog->aux)) {
+		ret = bpf_prog_offload_verifier_prep(env->prog);
+		if (ret)
+			goto skip_full_check;
+	}
+
+	ret = check_cfg(env);
+	if (ret < 0)
+		goto skip_full_check;
+
+	ret = do_check_subprogs(env);
+	ret = ret ?: do_check_main(env);
+
+	if (ret == 0 && bpf_prog_is_dev_bound(env->prog->aux))
+		ret = bpf_prog_offload_finalize(env);
+
+skip_full_check:
+	kvfree(env->explored_states);
+
+	if (ret == 0)
+		ret = check_max_stack_depth(env);
+
+	/* instruction rewrites happen after this point */
+	if (ret == 0)
+		ret = optimize_bpf_loop(env);
+
+	if (is_priv) {
+		if (ret == 0)
+			opt_hard_wire_dead_code_branches(env);
+		if (ret == 0)
+			ret = opt_remove_dead_code(env);
+		if (ret == 0)
+			ret = opt_remove_nops(env);
+	} else {
+		if (ret == 0)
+			sanitize_dead_code(env);
+	}
+
+	if (ret == 0)
+		/* program is valid, convert *(u32*)(ctx + off) accesses */
+		ret = convert_ctx_accesses(env);
+
+	if (ret == 0)
+		ret = do_misc_fixups(env);
+
+	/* do 32-bit optimization after insn patching has done so those patched
+	 * insns could be handled correctly.
+	 */
+	if (ret == 0 && !bpf_prog_is_dev_bound(env->prog->aux)) {
+		ret = opt_subreg_zext_lo32_rnd_hi32(env, attr);
+		env->prog->aux->verifier_zext = bpf_jit_needs_zext() ? !ret
+								     : false;
+	}
+
+	if (ret == 0)
+		ret = fixup_call_args(env);
+
+	env->verification_time = ktime_get_ns() - start_time;
+	print_verification_stats(env);
+	env->prog->aux->verified_insns = env->insn_processed;
+
+	if (log->level && bpf_verifier_log_full(log))
+		ret = -ENOSPC;
+	if (log->level && !log->ubuf) {
+		ret = -EFAULT;
+		goto err_release_maps;
+	}
+
+	if (ret)
+		goto err_release_maps;
+
+	if (env->used_map_cnt) {
+		/* if program passed verifier, update used_maps in bpf_prog_info */
+		env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt,
+							  sizeof(env->used_maps[0]),
+							  GFP_KERNEL);
+
+		if (!env->prog->aux->used_maps) {
+			ret = -ENOMEM;
+			goto err_release_maps;
+		}
+
+		memcpy(env->prog->aux->used_maps, env->used_maps,
+		       sizeof(env->used_maps[0]) * env->used_map_cnt);
+		env->prog->aux->used_map_cnt = env->used_map_cnt;
+	}
+	if (env->used_btf_cnt) {
+		/* if program passed verifier, update used_btfs in bpf_prog_aux */
+		env->prog->aux->used_btfs = kmalloc_array(env->used_btf_cnt,
+							  sizeof(env->used_btfs[0]),
+							  GFP_KERNEL);
+		if (!env->prog->aux->used_btfs) {
+			ret = -ENOMEM;
+			goto err_release_maps;
+		}
+
+		memcpy(env->prog->aux->used_btfs, env->used_btfs,
+		       sizeof(env->used_btfs[0]) * env->used_btf_cnt);
+		env->prog->aux->used_btf_cnt = env->used_btf_cnt;
+	}
+	if (env->used_map_cnt || env->used_btf_cnt) {
+		/* program is valid. Convert pseudo bpf_ld_imm64 into generic
+		 * bpf_ld_imm64 instructions
+		 */
+		convert_pseudo_ld_imm64(env);
+	}
+
+	adjust_btf_func(env);
+
+err_release_maps:
+	if (!env->prog->aux->used_maps)
+		/* if we didn't copy map pointers into bpf_prog_info, release
+		 * them now. Otherwise free_used_maps() will release them.
+		 */
+		release_maps(env);
+	if (!env->prog->aux->used_btfs)
+		release_btfs(env);
+
+	/* extension progs temporarily inherit the attach_type of their targets
+	   for verification purposes, so set it back to zero before returning
+	 */
+	if (env->prog->type == BPF_PROG_TYPE_EXT)
+		env->prog->expected_attach_type = 0;
+
+	*prog = env->prog;
+err_unlock:
+	if (!is_priv)
+		mutex_unlock(&bpf_verifier_lock);
+	vfree(env->insn_aux_data);
+err_free_env:
+	kfree(env);
+	return ret;
+}
diff --git a/kernel/capability.c b/kernel/capability.c
new file mode 100644
index 000000000..765194f5d
--- /dev/null
+++ b/kernel/capability.c
@@ -0,0 +1,535 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/kernel/capability.c
+ *
+ * Copyright (C) 1997  Andrew Main <zefram@fysh.org>
+ *
+ * Integrated into 2.1.97+,  Andrew G. Morgan <morgan@kernel.org>
+ * 30 May 2002:	Cleanup, Robert M. Love <rml@tech9.net>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/audit.h>
+#include <linux/capability.h>
+#include <linux/mm.h>
+#include <linux/export.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
+#include <linux/uaccess.h>
+
+/*
+ * Leveraged for setting/resetting capabilities
+ */
+
+const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;
+EXPORT_SYMBOL(__cap_empty_set);
+
+int file_caps_enabled = 1;
+
+static int __init file_caps_disable(char *str)
+{
+	file_caps_enabled = 0;
+	return 1;
+}
+__setup("no_file_caps", file_caps_disable);
+
+#ifdef CONFIG_MULTIUSER
+/*
+ * More recent versions of libcap are available from:
+ *
+ *   http://www.kernel.org/pub/linux/libs/security/linux-privs/
+ */
+
+static void warn_legacy_capability_use(void)
+{
+	char name[sizeof(current->comm)];
+
+	pr_info_once("warning: `%s' uses 32-bit capabilities (legacy support in use)\n",
+		     get_task_comm(name, current));
+}
+
+/*
+ * Version 2 capabilities worked fine, but the linux/capability.h file
+ * that accompanied their introduction encouraged their use without
+ * the necessary user-space source code changes. As such, we have
+ * created a version 3 with equivalent functionality to version 2, but
+ * with a header change to protect legacy source code from using
+ * version 2 when it wanted to use version 1. If your system has code
+ * that trips the following warning, it is using version 2 specific
+ * capabilities and may be doing so insecurely.
+ *
+ * The remedy is to either upgrade your version of libcap (to 2.10+,
+ * if the application is linked against it), or recompile your
+ * application with modern kernel headers and this warning will go
+ * away.
+ */
+
+static void warn_deprecated_v2(void)
+{
+	char name[sizeof(current->comm)];
+
+	pr_info_once("warning: `%s' uses deprecated v2 capabilities in a way that may be insecure\n",
+		     get_task_comm(name, current));
+}
+
+/*
+ * Version check. Return the number of u32s in each capability flag
+ * array, or a negative value on error.
+ */
+static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
+{
+	__u32 version;
+
+	if (get_user(version, &header->version))
+		return -EFAULT;
+
+	switch (version) {
+	case _LINUX_CAPABILITY_VERSION_1:
+		warn_legacy_capability_use();
+		*tocopy = _LINUX_CAPABILITY_U32S_1;
+		break;
+	case _LINUX_CAPABILITY_VERSION_2:
+		warn_deprecated_v2();
+		fallthrough;	/* v3 is otherwise equivalent to v2 */
+	case _LINUX_CAPABILITY_VERSION_3:
+		*tocopy = _LINUX_CAPABILITY_U32S_3;
+		break;
+	default:
+		if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version))
+			return -EFAULT;
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * The only thing that can change the capabilities of the current
+ * process is the current process. As such, we can't be in this code
+ * at the same time as we are in the process of setting capabilities
+ * in this process. The net result is that we can limit our use of
+ * locks to when we are reading the caps of another process.
+ */
+static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
+				     kernel_cap_t *pIp, kernel_cap_t *pPp)
+{
+	int ret;
+
+	if (pid && (pid != task_pid_vnr(current))) {
+		struct task_struct *target;
+
+		rcu_read_lock();
+
+		target = find_task_by_vpid(pid);
+		if (!target)
+			ret = -ESRCH;
+		else
+			ret = security_capget(target, pEp, pIp, pPp);
+
+		rcu_read_unlock();
+	} else
+		ret = security_capget(current, pEp, pIp, pPp);
+
+	return ret;
+}
+
+/**
+ * sys_capget - get the capabilities of a given process.
+ * @header: pointer to struct that contains capability version and
+ *	target pid data
+ * @dataptr: pointer to struct that contains the effective, permitted,
+ *	and inheritable capabilities that are returned
+ *
+ * Returns 0 on success and < 0 on error.
+ */
+SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr)
+{
+	int ret = 0;
+	pid_t pid;
+	unsigned tocopy;
+	kernel_cap_t pE, pI, pP;
+
+	ret = cap_validate_magic(header, &tocopy);
+	if ((dataptr == NULL) || (ret != 0))
+		return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret;
+
+	if (get_user(pid, &header->pid))
+		return -EFAULT;
+
+	if (pid < 0)
+		return -EINVAL;
+
+	ret = cap_get_target_pid(pid, &pE, &pI, &pP);
+	if (!ret) {
+		struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
+		unsigned i;
+
+		for (i = 0; i < tocopy; i++) {
+			kdata[i].effective = pE.cap[i];
+			kdata[i].permitted = pP.cap[i];
+			kdata[i].inheritable = pI.cap[i];
+		}
+
+		/*
+		 * Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S,
+		 * we silently drop the upper capabilities here. This
+		 * has the effect of making older libcap
+		 * implementations implicitly drop upper capability
+		 * bits when they perform a: capget/modify/capset
+		 * sequence.
+		 *
+		 * This behavior is considered fail-safe
+		 * behavior. Upgrading the application to a newer
+		 * version of libcap will enable access to the newer
+		 * capabilities.
+		 *
+		 * An alternative would be to return an error here
+		 * (-ERANGE), but that causes legacy applications to
+		 * unexpectedly fail; the capget/modify/capset aborts
+		 * before modification is attempted and the application
+		 * fails.
+		 */
+		if (copy_to_user(dataptr, kdata, tocopy
+				 * sizeof(struct __user_cap_data_struct))) {
+			return -EFAULT;
+		}
+	}
+
+	return ret;
+}
+
+/**
+ * sys_capset - set capabilities for a process or (*) a group of processes
+ * @header: pointer to struct that contains capability version and
+ *	target pid data
+ * @data: pointer to struct that contains the effective, permitted,
+ *	and inheritable capabilities
+ *
+ * Set capabilities for the current process only.  The ability to any other
+ * process(es) has been deprecated and removed.
+ *
+ * The restrictions on setting capabilities are specified as:
+ *
+ * I: any raised capabilities must be a subset of the old permitted
+ * P: any raised capabilities must be a subset of the old permitted
+ * E: must be set to a subset of new permitted
+ *
+ * Returns 0 on success and < 0 on error.
+ */
+SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data)
+{
+	struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
+	unsigned i, tocopy, copybytes;
+	kernel_cap_t inheritable, permitted, effective;
+	struct cred *new;
+	int ret;
+	pid_t pid;
+
+	ret = cap_validate_magic(header, &tocopy);
+	if (ret != 0)
+		return ret;
+
+	if (get_user(pid, &header->pid))
+		return -EFAULT;
+
+	/* may only affect current now */
+	if (pid != 0 && pid != task_pid_vnr(current))
+		return -EPERM;
+
+	copybytes = tocopy * sizeof(struct __user_cap_data_struct);
+	if (copybytes > sizeof(kdata))
+		return -EFAULT;
+
+	if (copy_from_user(&kdata, data, copybytes))
+		return -EFAULT;
+
+	for (i = 0; i < tocopy; i++) {
+		effective.cap[i] = kdata[i].effective;
+		permitted.cap[i] = kdata[i].permitted;
+		inheritable.cap[i] = kdata[i].inheritable;
+	}
+	while (i < _KERNEL_CAPABILITY_U32S) {
+		effective.cap[i] = 0;
+		permitted.cap[i] = 0;
+		inheritable.cap[i] = 0;
+		i++;
+	}
+
+	effective.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
+	permitted.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
+	inheritable.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
+
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+
+	ret = security_capset(new, current_cred(),
+			      &effective, &inheritable, &permitted);
+	if (ret < 0)
+		goto error;
+
+	audit_log_capset(new, current_cred());
+
+	return commit_creds(new);
+
+error:
+	abort_creds(new);
+	return ret;
+}
+
+/**
+ * has_ns_capability - Does a task have a capability in a specific user ns
+ * @t: The task in question
+ * @ns: target user namespace
+ * @cap: The capability to be tested for
+ *
+ * Return true if the specified task has the given superior capability
+ * currently in effect to the specified user namespace, false if not.
+ *
+ * Note that this does not set PF_SUPERPRIV on the task.
+ */
+bool has_ns_capability(struct task_struct *t,
+		       struct user_namespace *ns, int cap)
+{
+	int ret;
+
+	rcu_read_lock();
+	ret = security_capable(__task_cred(t), ns, cap, CAP_OPT_NONE);
+	rcu_read_unlock();
+
+	return (ret == 0);
+}
+
+/**
+ * has_capability - Does a task have a capability in init_user_ns
+ * @t: The task in question
+ * @cap: The capability to be tested for
+ *
+ * Return true if the specified task has the given superior capability
+ * currently in effect to the initial user namespace, false if not.
+ *
+ * Note that this does not set PF_SUPERPRIV on the task.
+ */
+bool has_capability(struct task_struct *t, int cap)
+{
+	return has_ns_capability(t, &init_user_ns, cap);
+}
+EXPORT_SYMBOL(has_capability);
+
+/**
+ * has_ns_capability_noaudit - Does a task have a capability (unaudited)
+ * in a specific user ns.
+ * @t: The task in question
+ * @ns: target user namespace
+ * @cap: The capability to be tested for
+ *
+ * Return true if the specified task has the given superior capability
+ * currently in effect to the specified user namespace, false if not.
+ * Do not write an audit message for the check.
+ *
+ * Note that this does not set PF_SUPERPRIV on the task.
+ */
+bool has_ns_capability_noaudit(struct task_struct *t,
+			       struct user_namespace *ns, int cap)
+{
+	int ret;
+
+	rcu_read_lock();
+	ret = security_capable(__task_cred(t), ns, cap, CAP_OPT_NOAUDIT);
+	rcu_read_unlock();
+
+	return (ret == 0);
+}
+
+/**
+ * has_capability_noaudit - Does a task have a capability (unaudited) in the
+ * initial user ns
+ * @t: The task in question
+ * @cap: The capability to be tested for
+ *
+ * Return true if the specified task has the given superior capability
+ * currently in effect to init_user_ns, false if not.  Don't write an
+ * audit message for the check.
+ *
+ * Note that this does not set PF_SUPERPRIV on the task.
+ */
+bool has_capability_noaudit(struct task_struct *t, int cap)
+{
+	return has_ns_capability_noaudit(t, &init_user_ns, cap);
+}
+EXPORT_SYMBOL(has_capability_noaudit);
+
+static bool ns_capable_common(struct user_namespace *ns,
+			      int cap,
+			      unsigned int opts)
+{
+	int capable;
+
+	if (unlikely(!cap_valid(cap))) {
+		pr_crit("capable() called with invalid cap=%u\n", cap);
+		BUG();
+	}
+
+	capable = security_capable(current_cred(), ns, cap, opts);
+	if (capable == 0) {
+		current->flags |= PF_SUPERPRIV;
+		return true;
+	}
+	return false;
+}
+
+/**
+ * ns_capable - Determine if the current task has a superior capability in effect
+ * @ns:  The usernamespace we want the capability in
+ * @cap: The capability to be tested for
+ *
+ * Return true if the current task has the given superior capability currently
+ * available for use, false if not.
+ *
+ * This sets PF_SUPERPRIV on the task if the capability is available on the
+ * assumption that it's about to be used.
+ */
+bool ns_capable(struct user_namespace *ns, int cap)
+{
+	return ns_capable_common(ns, cap, CAP_OPT_NONE);
+}
+EXPORT_SYMBOL(ns_capable);
+
+/**
+ * ns_capable_noaudit - Determine if the current task has a superior capability
+ * (unaudited) in effect
+ * @ns:  The usernamespace we want the capability in
+ * @cap: The capability to be tested for
+ *
+ * Return true if the current task has the given superior capability currently
+ * available for use, false if not.
+ *
+ * This sets PF_SUPERPRIV on the task if the capability is available on the
+ * assumption that it's about to be used.
+ */
+bool ns_capable_noaudit(struct user_namespace *ns, int cap)
+{
+	return ns_capable_common(ns, cap, CAP_OPT_NOAUDIT);
+}
+EXPORT_SYMBOL(ns_capable_noaudit);
+
+/**
+ * ns_capable_setid - Determine if the current task has a superior capability
+ * in effect, while signalling that this check is being done from within a
+ * setid or setgroups syscall.
+ * @ns:  The usernamespace we want the capability in
+ * @cap: The capability to be tested for
+ *
+ * Return true if the current task has the given superior capability currently
+ * available for use, false if not.
+ *
+ * This sets PF_SUPERPRIV on the task if the capability is available on the
+ * assumption that it's about to be used.
+ */
+bool ns_capable_setid(struct user_namespace *ns, int cap)
+{
+	return ns_capable_common(ns, cap, CAP_OPT_INSETID);
+}
+EXPORT_SYMBOL(ns_capable_setid);
+
+/**
+ * capable - Determine if the current task has a superior capability in effect
+ * @cap: The capability to be tested for
+ *
+ * Return true if the current task has the given superior capability currently
+ * available for use, false if not.
+ *
+ * This sets PF_SUPERPRIV on the task if the capability is available on the
+ * assumption that it's about to be used.
+ */
+bool capable(int cap)
+{
+	return ns_capable(&init_user_ns, cap);
+}
+EXPORT_SYMBOL(capable);
+#endif /* CONFIG_MULTIUSER */
+
+/**
+ * file_ns_capable - Determine if the file's opener had a capability in effect
+ * @file:  The file we want to check
+ * @ns:  The usernamespace we want the capability in
+ * @cap: The capability to be tested for
+ *
+ * Return true if task that opened the file had a capability in effect
+ * when the file was opened.
+ *
+ * This does not set PF_SUPERPRIV because the caller may not
+ * actually be privileged.
+ */
+bool file_ns_capable(const struct file *file, struct user_namespace *ns,
+		     int cap)
+{
+
+	if (WARN_ON_ONCE(!cap_valid(cap)))
+		return false;
+
+	if (security_capable(file->f_cred, ns, cap, CAP_OPT_NONE) == 0)
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL(file_ns_capable);
+
+/**
+ * privileged_wrt_inode_uidgid - Do capabilities in the namespace work over the inode?
+ * @ns: The user namespace in question
+ * @inode: The inode in question
+ *
+ * Return true if the inode uid and gid are within the namespace.
+ */
+bool privileged_wrt_inode_uidgid(struct user_namespace *ns,
+				 struct user_namespace *mnt_userns,
+				 const struct inode *inode)
+{
+	return kuid_has_mapping(ns, i_uid_into_mnt(mnt_userns, inode)) &&
+	       kgid_has_mapping(ns, i_gid_into_mnt(mnt_userns, inode));
+}
+
+/**
+ * capable_wrt_inode_uidgid - Check nsown_capable and uid and gid mapped
+ * @inode: The inode in question
+ * @cap: The capability in question
+ *
+ * Return true if the current task has the given capability targeted at
+ * its own user namespace and that the given inode's uid and gid are
+ * mapped into the current user namespace.
+ */
+bool capable_wrt_inode_uidgid(struct user_namespace *mnt_userns,
+			      const struct inode *inode, int cap)
+{
+	struct user_namespace *ns = current_user_ns();
+
+	return ns_capable(ns, cap) &&
+	       privileged_wrt_inode_uidgid(ns, mnt_userns, inode);
+}
+EXPORT_SYMBOL(capable_wrt_inode_uidgid);
+
+/**
+ * ptracer_capable - Determine if the ptracer holds CAP_SYS_PTRACE in the namespace
+ * @tsk: The task that may be ptraced
+ * @ns: The user namespace to search for CAP_SYS_PTRACE in
+ *
+ * Return true if the task that is ptracing the current task had CAP_SYS_PTRACE
+ * in the specified user namespace.
+ */
+bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns)
+{
+	int ret = 0;  /* An absent tracer adds no restrictions */
+	const struct cred *cred;
+
+	rcu_read_lock();
+	cred = rcu_dereference(tsk->ptracer_cred);
+	if (cred)
+		ret = security_capable(cred, ns, CAP_SYS_PTRACE,
+				       CAP_OPT_NOAUDIT);
+	rcu_read_unlock();
+	return (ret == 0);
+}
diff --git a/kernel/cfi.c b/kernel/cfi.c
new file mode 100644
index 000000000..08caad776
--- /dev/null
+++ b/kernel/cfi.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Clang Control Flow Integrity (CFI) error handling.
+ *
+ * Copyright (C) 2022 Google LLC
+ */
+
+#include <linux/cfi.h>
+
+enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr,
+				      unsigned long *target, u32 type)
+{
+	if (target)
+		pr_err("CFI failure at %pS (target: %pS; expected type: 0x%08x)\n",
+		       (void *)addr, (void *)*target, type);
+	else
+		pr_err("CFI failure at %pS (no target information)\n",
+		       (void *)addr);
+
+	if (IS_ENABLED(CONFIG_CFI_PERMISSIVE)) {
+		__warn(NULL, 0, (void *)addr, 0, regs, NULL);
+		return BUG_TRAP_TYPE_WARN;
+	}
+
+	return BUG_TRAP_TYPE_BUG;
+}
+
+#ifdef CONFIG_ARCH_USES_CFI_TRAPS
+static inline unsigned long trap_address(s32 *p)
+{
+	return (unsigned long)((long)p + (long)*p);
+}
+
+static bool is_trap(unsigned long addr, s32 *start, s32 *end)
+{
+	s32 *p;
+
+	for (p = start; p < end; ++p) {
+		if (trap_address(p) == addr)
+			return true;
+	}
+
+	return false;
+}
+
+#ifdef CONFIG_MODULES
+/* Populates `kcfi_trap(_end)?` fields in `struct module`. */
+void module_cfi_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
+			 struct module *mod)
+{
+	char *secstrings;
+	unsigned int i;
+
+	mod->kcfi_traps = NULL;
+	mod->kcfi_traps_end = NULL;
+
+	secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+
+	for (i = 1; i < hdr->e_shnum; i++) {
+		if (strcmp(secstrings + sechdrs[i].sh_name, "__kcfi_traps"))
+			continue;
+
+		mod->kcfi_traps = (s32 *)sechdrs[i].sh_addr;
+		mod->kcfi_traps_end = (s32 *)(sechdrs[i].sh_addr + sechdrs[i].sh_size);
+		break;
+	}
+}
+
+static bool is_module_cfi_trap(unsigned long addr)
+{
+	struct module *mod;
+	bool found = false;
+
+	rcu_read_lock_sched_notrace();
+
+	mod = __module_address(addr);
+	if (mod)
+		found = is_trap(addr, mod->kcfi_traps, mod->kcfi_traps_end);
+
+	rcu_read_unlock_sched_notrace();
+
+	return found;
+}
+#else /* CONFIG_MODULES */
+static inline bool is_module_cfi_trap(unsigned long addr)
+{
+	return false;
+}
+#endif /* CONFIG_MODULES */
+
+extern s32 __start___kcfi_traps[];
+extern s32 __stop___kcfi_traps[];
+
+bool is_cfi_trap(unsigned long addr)
+{
+	if (is_trap(addr, __start___kcfi_traps, __stop___kcfi_traps))
+		return true;
+
+	return is_module_cfi_trap(addr);
+}
+#endif /* CONFIG_ARCH_USES_CFI_TRAPS */
diff --git a/kernel/cgroup/Makefile b/kernel/cgroup/Makefile
new file mode 100644
index 000000000..12f8457ad
--- /dev/null
+++ b/kernel/cgroup/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y := cgroup.o rstat.o namespace.o cgroup-v1.o freezer.o
+
+obj-$(CONFIG_CGROUP_FREEZER) += legacy_freezer.o
+obj-$(CONFIG_CGROUP_PIDS) += pids.o
+obj-$(CONFIG_CGROUP_RDMA) += rdma.o
+obj-$(CONFIG_CPUSETS) += cpuset.o
+obj-$(CONFIG_CGROUP_MISC) += misc.o
+obj-$(CONFIG_CGROUP_DEBUG) += debug.o
diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
new file mode 100644
index 000000000..367b0a42a
--- /dev/null
+++ b/kernel/cgroup/cgroup-internal.h
@@ -0,0 +1,298 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __CGROUP_INTERNAL_H
+#define __CGROUP_INTERNAL_H
+
+#include <linux/cgroup.h>
+#include <linux/kernfs.h>
+#include <linux/workqueue.h>
+#include <linux/list.h>
+#include <linux/refcount.h>
+#include <linux/fs_parser.h>
+
+#define TRACE_CGROUP_PATH_LEN 1024
+extern spinlock_t trace_cgroup_path_lock;
+extern char trace_cgroup_path[TRACE_CGROUP_PATH_LEN];
+extern void __init enable_debug_cgroup(void);
+
+/*
+ * cgroup_path() takes a spin lock. It is good practice not to take
+ * spin locks within trace point handlers, as they are mostly hidden
+ * from normal view. As cgroup_path() can take the kernfs_rename_lock
+ * spin lock, it is best to not call that function from the trace event
+ * handler.
+ *
+ * Note: trace_cgroup_##type##_enabled() is a static branch that will only
+ *       be set when the trace event is enabled.
+ */
+#define TRACE_CGROUP_PATH(type, cgrp, ...)				\
+	do {								\
+		if (trace_cgroup_##type##_enabled()) {			\
+			unsigned long flags;				\
+			spin_lock_irqsave(&trace_cgroup_path_lock,	\
+					  flags);			\
+			cgroup_path(cgrp, trace_cgroup_path,		\
+				    TRACE_CGROUP_PATH_LEN);		\
+			trace_cgroup_##type(cgrp, trace_cgroup_path,	\
+					    ##__VA_ARGS__);		\
+			spin_unlock_irqrestore(&trace_cgroup_path_lock, \
+					       flags);			\
+		}							\
+	} while (0)
+
+/*
+ * The cgroup filesystem superblock creation/mount context.
+ */
+struct cgroup_fs_context {
+	struct kernfs_fs_context kfc;
+	struct cgroup_root	*root;
+	struct cgroup_namespace	*ns;
+	unsigned int	flags;			/* CGRP_ROOT_* flags */
+
+	/* cgroup1 bits */
+	bool		cpuset_clone_children;
+	bool		none;			/* User explicitly requested empty subsystem */
+	bool		all_ss;			/* Seen 'all' option */
+	u16		subsys_mask;		/* Selected subsystems */
+	char		*name;			/* Hierarchy name */
+	char		*release_agent;		/* Path for release notifications */
+};
+
+static inline struct cgroup_fs_context *cgroup_fc2context(struct fs_context *fc)
+{
+	struct kernfs_fs_context *kfc = fc->fs_private;
+
+	return container_of(kfc, struct cgroup_fs_context, kfc);
+}
+
+struct cgroup_pidlist;
+
+struct cgroup_file_ctx {
+	struct cgroup_namespace	*ns;
+
+	struct {
+		void			*trigger;
+	} psi;
+
+	struct {
+		bool			started;
+		struct css_task_iter	iter;
+	} procs;
+
+	struct {
+		struct cgroup_pidlist	*pidlist;
+	} procs1;
+};
+
+/*
+ * A cgroup can be associated with multiple css_sets as different tasks may
+ * belong to different cgroups on different hierarchies.  In the other
+ * direction, a css_set is naturally associated with multiple cgroups.
+ * This M:N relationship is represented by the following link structure
+ * which exists for each association and allows traversing the associations
+ * from both sides.
+ */
+struct cgrp_cset_link {
+	/* the cgroup and css_set this link associates */
+	struct cgroup		*cgrp;
+	struct css_set		*cset;
+
+	/* list of cgrp_cset_links anchored at cgrp->cset_links */
+	struct list_head	cset_link;
+
+	/* list of cgrp_cset_links anchored at css_set->cgrp_links */
+	struct list_head	cgrp_link;
+};
+
+/* used to track tasks and csets during migration */
+struct cgroup_taskset {
+	/* the src and dst cset list running through cset->mg_node */
+	struct list_head	src_csets;
+	struct list_head	dst_csets;
+
+	/* the number of tasks in the set */
+	int			nr_tasks;
+
+	/* the subsys currently being processed */
+	int			ssid;
+
+	/*
+	 * Fields for cgroup_taskset_*() iteration.
+	 *
+	 * Before migration is committed, the target migration tasks are on
+	 * ->mg_tasks of the csets on ->src_csets.  After, on ->mg_tasks of
+	 * the csets on ->dst_csets.  ->csets point to either ->src_csets
+	 * or ->dst_csets depending on whether migration is committed.
+	 *
+	 * ->cur_csets and ->cur_task point to the current task position
+	 * during iteration.
+	 */
+	struct list_head	*csets;
+	struct css_set		*cur_cset;
+	struct task_struct	*cur_task;
+};
+
+/* migration context also tracks preloading */
+struct cgroup_mgctx {
+	/*
+	 * Preloaded source and destination csets.  Used to guarantee
+	 * atomic success or failure on actual migration.
+	 */
+	struct list_head	preloaded_src_csets;
+	struct list_head	preloaded_dst_csets;
+
+	/* tasks and csets to migrate */
+	struct cgroup_taskset	tset;
+
+	/* subsystems affected by migration */
+	u16			ss_mask;
+};
+
+#define CGROUP_TASKSET_INIT(tset)						\
+{										\
+	.src_csets		= LIST_HEAD_INIT(tset.src_csets),		\
+	.dst_csets		= LIST_HEAD_INIT(tset.dst_csets),		\
+	.csets			= &tset.src_csets,				\
+}
+
+#define CGROUP_MGCTX_INIT(name)							\
+{										\
+	LIST_HEAD_INIT(name.preloaded_src_csets),				\
+	LIST_HEAD_INIT(name.preloaded_dst_csets),				\
+	CGROUP_TASKSET_INIT(name.tset),						\
+}
+
+#define DEFINE_CGROUP_MGCTX(name)						\
+	struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
+
+extern spinlock_t css_set_lock;
+extern struct cgroup_subsys *cgroup_subsys[];
+extern struct list_head cgroup_roots;
+
+/* iterate across the hierarchies */
+#define for_each_root(root)						\
+	list_for_each_entry((root), &cgroup_roots, root_list)
+
+/**
+ * for_each_subsys - iterate all enabled cgroup subsystems
+ * @ss: the iteration cursor
+ * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
+ */
+#define for_each_subsys(ss, ssid)					\
+	for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT &&		\
+	     (((ss) = cgroup_subsys[ssid]) || true); (ssid)++)
+
+static inline bool cgroup_is_dead(const struct cgroup *cgrp)
+{
+	return !(cgrp->self.flags & CSS_ONLINE);
+}
+
+static inline bool notify_on_release(const struct cgroup *cgrp)
+{
+	return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
+}
+
+void put_css_set_locked(struct css_set *cset);
+
+static inline void put_css_set(struct css_set *cset)
+{
+	unsigned long flags;
+
+	/*
+	 * Ensure that the refcount doesn't hit zero while any readers
+	 * can see it. Similar to atomic_dec_and_lock(), but for an
+	 * rwlock
+	 */
+	if (refcount_dec_not_one(&cset->refcount))
+		return;
+
+	spin_lock_irqsave(&css_set_lock, flags);
+	put_css_set_locked(cset);
+	spin_unlock_irqrestore(&css_set_lock, flags);
+}
+
+/*
+ * refcounted get/put for css_set objects
+ */
+static inline void get_css_set(struct css_set *cset)
+{
+	refcount_inc(&cset->refcount);
+}
+
+bool cgroup_ssid_enabled(int ssid);
+bool cgroup_on_dfl(const struct cgroup *cgrp);
+bool cgroup_is_thread_root(struct cgroup *cgrp);
+bool cgroup_is_threaded(struct cgroup *cgrp);
+
+struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root);
+struct cgroup *task_cgroup_from_root(struct task_struct *task,
+				     struct cgroup_root *root);
+struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline);
+void cgroup_kn_unlock(struct kernfs_node *kn);
+int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
+			  struct cgroup_namespace *ns);
+
+void cgroup_favor_dynmods(struct cgroup_root *root, bool favor);
+void cgroup_free_root(struct cgroup_root *root);
+void init_cgroup_root(struct cgroup_fs_context *ctx);
+int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask);
+int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
+int cgroup_do_get_tree(struct fs_context *fc);
+
+int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp);
+void cgroup_migrate_finish(struct cgroup_mgctx *mgctx);
+void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp,
+			    struct cgroup_mgctx *mgctx);
+int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx);
+int cgroup_migrate(struct task_struct *leader, bool threadgroup,
+		   struct cgroup_mgctx *mgctx);
+
+int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
+		       bool threadgroup);
+void cgroup_attach_lock(bool lock_threadgroup);
+void cgroup_attach_unlock(bool lock_threadgroup);
+struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup,
+					     bool *locked)
+	__acquires(&cgroup_threadgroup_rwsem);
+void cgroup_procs_write_finish(struct task_struct *task, bool locked)
+	__releases(&cgroup_threadgroup_rwsem);
+
+void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
+
+int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode);
+int cgroup_rmdir(struct kernfs_node *kn);
+int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
+		     struct kernfs_root *kf_root);
+
+int __cgroup_task_count(const struct cgroup *cgrp);
+int cgroup_task_count(const struct cgroup *cgrp);
+
+/*
+ * rstat.c
+ */
+int cgroup_rstat_init(struct cgroup *cgrp);
+void cgroup_rstat_exit(struct cgroup *cgrp);
+void cgroup_rstat_boot(void);
+void cgroup_base_stat_cputime_show(struct seq_file *seq);
+
+/*
+ * namespace.c
+ */
+extern const struct proc_ns_operations cgroupns_operations;
+
+/*
+ * cgroup-v1.c
+ */
+extern struct cftype cgroup1_base_files[];
+extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
+extern const struct fs_parameter_spec cgroup1_fs_parameters[];
+
+int proc_cgroupstats_show(struct seq_file *m, void *v);
+bool cgroup1_ssid_disabled(int ssid);
+void cgroup1_pidlist_destroy_all(struct cgroup *cgrp);
+void cgroup1_release_agent(struct work_struct *work);
+void cgroup1_check_for_release(struct cgroup *cgrp);
+int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param);
+int cgroup1_get_tree(struct fs_context *fc);
+int cgroup1_reconfigure(struct fs_context *ctx);
+
+#endif /* __CGROUP_INTERNAL_H */
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
new file mode 100644
index 000000000..289cc873c
--- /dev/null
+++ b/kernel/cgroup/cgroup-v1.c
@@ -0,0 +1,1308 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "cgroup-internal.h"
+
+#include <linux/ctype.h>
+#include <linux/kmod.h>
+#include <linux/sort.h>
+#include <linux/delay.h>
+#include <linux/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/task.h>
+#include <linux/magic.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/delayacct.h>
+#include <linux/pid_namespace.h>
+#include <linux/cgroupstats.h>
+#include <linux/fs_parser.h>
+
+#include <trace/events/cgroup.h>
+
+/*
+ * pidlists linger the following amount before being destroyed.  The goal
+ * is avoiding frequent destruction in the middle of consecutive read calls
+ * Expiring in the middle is a performance problem not a correctness one.
+ * 1 sec should be enough.
+ */
+#define CGROUP_PIDLIST_DESTROY_DELAY	HZ
+
+/* Controllers blocked by the commandline in v1 */
+static u16 cgroup_no_v1_mask;
+
+/* disable named v1 mounts */
+static bool cgroup_no_v1_named;
+
+/*
+ * pidlist destructions need to be flushed on cgroup destruction.  Use a
+ * separate workqueue as flush domain.
+ */
+static struct workqueue_struct *cgroup_pidlist_destroy_wq;
+
+/* protects cgroup_subsys->release_agent_path */
+static DEFINE_SPINLOCK(release_agent_path_lock);
+
+bool cgroup1_ssid_disabled(int ssid)
+{
+	return cgroup_no_v1_mask & (1 << ssid);
+}
+
+/**
+ * cgroup_attach_task_all - attach task 'tsk' to all cgroups of task 'from'
+ * @from: attach to all cgroups of a given task
+ * @tsk: the task to be attached
+ *
+ * Return: %0 on success or a negative errno code on failure
+ */
+int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk)
+{
+	struct cgroup_root *root;
+	int retval = 0;
+
+	cgroup_lock();
+	cgroup_attach_lock(true);
+	for_each_root(root) {
+		struct cgroup *from_cgrp;
+
+		spin_lock_irq(&css_set_lock);
+		from_cgrp = task_cgroup_from_root(from, root);
+		spin_unlock_irq(&css_set_lock);
+
+		retval = cgroup_attach_task(from_cgrp, tsk, false);
+		if (retval)
+			break;
+	}
+	cgroup_attach_unlock(true);
+	cgroup_unlock();
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(cgroup_attach_task_all);
+
+/**
+ * cgroup_transfer_tasks - move tasks from one cgroup to another
+ * @to: cgroup to which the tasks will be moved
+ * @from: cgroup in which the tasks currently reside
+ *
+ * Locking rules between cgroup_post_fork() and the migration path
+ * guarantee that, if a task is forking while being migrated, the new child
+ * is guaranteed to be either visible in the source cgroup after the
+ * parent's migration is complete or put into the target cgroup.  No task
+ * can slip out of migration through forking.
+ *
+ * Return: %0 on success or a negative errno code on failure
+ */
+int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
+{
+	DEFINE_CGROUP_MGCTX(mgctx);
+	struct cgrp_cset_link *link;
+	struct css_task_iter it;
+	struct task_struct *task;
+	int ret;
+
+	if (cgroup_on_dfl(to))
+		return -EINVAL;
+
+	ret = cgroup_migrate_vet_dst(to);
+	if (ret)
+		return ret;
+
+	cgroup_lock();
+
+	cgroup_attach_lock(true);
+
+	/* all tasks in @from are being moved, all csets are source */
+	spin_lock_irq(&css_set_lock);
+	list_for_each_entry(link, &from->cset_links, cset_link)
+		cgroup_migrate_add_src(link->cset, to, &mgctx);
+	spin_unlock_irq(&css_set_lock);
+
+	ret = cgroup_migrate_prepare_dst(&mgctx);
+	if (ret)
+		goto out_err;
+
+	/*
+	 * Migrate tasks one-by-one until @from is empty.  This fails iff
+	 * ->can_attach() fails.
+	 */
+	do {
+		css_task_iter_start(&from->self, 0, &it);
+
+		do {
+			task = css_task_iter_next(&it);
+		} while (task && (task->flags & PF_EXITING));
+
+		if (task)
+			get_task_struct(task);
+		css_task_iter_end(&it);
+
+		if (task) {
+			ret = cgroup_migrate(task, false, &mgctx);
+			if (!ret)
+				TRACE_CGROUP_PATH(transfer_tasks, to, task, false);
+			put_task_struct(task);
+		}
+	} while (task && !ret);
+out_err:
+	cgroup_migrate_finish(&mgctx);
+	cgroup_attach_unlock(true);
+	cgroup_unlock();
+	return ret;
+}
+
+/*
+ * Stuff for reading the 'tasks'/'procs' files.
+ *
+ * Reading this file can return large amounts of data if a cgroup has
+ * *lots* of attached tasks. So it may need several calls to read(),
+ * but we cannot guarantee that the information we produce is correct
+ * unless we produce it entirely atomically.
+ *
+ */
+
+/* which pidlist file are we talking about? */
+enum cgroup_filetype {
+	CGROUP_FILE_PROCS,
+	CGROUP_FILE_TASKS,
+};
+
+/*
+ * A pidlist is a list of pids that virtually represents the contents of one
+ * of the cgroup files ("procs" or "tasks"). We keep a list of such pidlists,
+ * a pair (one each for procs, tasks) for each pid namespace that's relevant
+ * to the cgroup.
+ */
+struct cgroup_pidlist {
+	/*
+	 * used to find which pidlist is wanted. doesn't change as long as
+	 * this particular list stays in the list.
+	*/
+	struct { enum cgroup_filetype type; struct pid_namespace *ns; } key;
+	/* array of xids */
+	pid_t *list;
+	/* how many elements the above list has */
+	int length;
+	/* each of these stored in a list by its cgroup */
+	struct list_head links;
+	/* pointer to the cgroup we belong to, for list removal purposes */
+	struct cgroup *owner;
+	/* for delayed destruction */
+	struct delayed_work destroy_dwork;
+};
+
+/*
+ * Used to destroy all pidlists lingering waiting for destroy timer.  None
+ * should be left afterwards.
+ */
+void cgroup1_pidlist_destroy_all(struct cgroup *cgrp)
+{
+	struct cgroup_pidlist *l, *tmp_l;
+
+	mutex_lock(&cgrp->pidlist_mutex);
+	list_for_each_entry_safe(l, tmp_l, &cgrp->pidlists, links)
+		mod_delayed_work(cgroup_pidlist_destroy_wq, &l->destroy_dwork, 0);
+	mutex_unlock(&cgrp->pidlist_mutex);
+
+	flush_workqueue(cgroup_pidlist_destroy_wq);
+	BUG_ON(!list_empty(&cgrp->pidlists));
+}
+
+static void cgroup_pidlist_destroy_work_fn(struct work_struct *work)
+{
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct cgroup_pidlist *l = container_of(dwork, struct cgroup_pidlist,
+						destroy_dwork);
+	struct cgroup_pidlist *tofree = NULL;
+
+	mutex_lock(&l->owner->pidlist_mutex);
+
+	/*
+	 * Destroy iff we didn't get queued again.  The state won't change
+	 * as destroy_dwork can only be queued while locked.
+	 */
+	if (!delayed_work_pending(dwork)) {
+		list_del(&l->links);
+		kvfree(l->list);
+		put_pid_ns(l->key.ns);
+		tofree = l;
+	}
+
+	mutex_unlock(&l->owner->pidlist_mutex);
+	kfree(tofree);
+}
+
+/*
+ * pidlist_uniq - given a kmalloc()ed list, strip out all duplicate entries
+ * Returns the number of unique elements.
+ */
+static int pidlist_uniq(pid_t *list, int length)
+{
+	int src, dest = 1;
+
+	/*
+	 * we presume the 0th element is unique, so i starts at 1. trivial
+	 * edge cases first; no work needs to be done for either
+	 */
+	if (length == 0 || length == 1)
+		return length;
+	/* src and dest walk down the list; dest counts unique elements */
+	for (src = 1; src < length; src++) {
+		/* find next unique element */
+		while (list[src] == list[src-1]) {
+			src++;
+			if (src == length)
+				goto after;
+		}
+		/* dest always points to where the next unique element goes */
+		list[dest] = list[src];
+		dest++;
+	}
+after:
+	return dest;
+}
+
+/*
+ * The two pid files - task and cgroup.procs - guaranteed that the result
+ * is sorted, which forced this whole pidlist fiasco.  As pid order is
+ * different per namespace, each namespace needs differently sorted list,
+ * making it impossible to use, for example, single rbtree of member tasks
+ * sorted by task pointer.  As pidlists can be fairly large, allocating one
+ * per open file is dangerous, so cgroup had to implement shared pool of
+ * pidlists keyed by cgroup and namespace.
+ */
+static int cmppid(const void *a, const void *b)
+{
+	return *(pid_t *)a - *(pid_t *)b;
+}
+
+static struct cgroup_pidlist *cgroup_pidlist_find(struct cgroup *cgrp,
+						  enum cgroup_filetype type)
+{
+	struct cgroup_pidlist *l;
+	/* don't need task_nsproxy() if we're looking at ourself */
+	struct pid_namespace *ns = task_active_pid_ns(current);
+
+	lockdep_assert_held(&cgrp->pidlist_mutex);
+
+	list_for_each_entry(l, &cgrp->pidlists, links)
+		if (l->key.type == type && l->key.ns == ns)
+			return l;
+	return NULL;
+}
+
+/*
+ * find the appropriate pidlist for our purpose (given procs vs tasks)
+ * returns with the lock on that pidlist already held, and takes care
+ * of the use count, or returns NULL with no locks held if we're out of
+ * memory.
+ */
+static struct cgroup_pidlist *cgroup_pidlist_find_create(struct cgroup *cgrp,
+						enum cgroup_filetype type)
+{
+	struct cgroup_pidlist *l;
+
+	lockdep_assert_held(&cgrp->pidlist_mutex);
+
+	l = cgroup_pidlist_find(cgrp, type);
+	if (l)
+		return l;
+
+	/* entry not found; create a new one */
+	l = kzalloc(sizeof(struct cgroup_pidlist), GFP_KERNEL);
+	if (!l)
+		return l;
+
+	INIT_DELAYED_WORK(&l->destroy_dwork, cgroup_pidlist_destroy_work_fn);
+	l->key.type = type;
+	/* don't need task_nsproxy() if we're looking at ourself */
+	l->key.ns = get_pid_ns(task_active_pid_ns(current));
+	l->owner = cgrp;
+	list_add(&l->links, &cgrp->pidlists);
+	return l;
+}
+
+/*
+ * Load a cgroup's pidarray with either procs' tgids or tasks' pids
+ */
+static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type,
+			      struct cgroup_pidlist **lp)
+{
+	pid_t *array;
+	int length;
+	int pid, n = 0; /* used for populating the array */
+	struct css_task_iter it;
+	struct task_struct *tsk;
+	struct cgroup_pidlist *l;
+
+	lockdep_assert_held(&cgrp->pidlist_mutex);
+
+	/*
+	 * If cgroup gets more users after we read count, we won't have
+	 * enough space - tough.  This race is indistinguishable to the
+	 * caller from the case that the additional cgroup users didn't
+	 * show up until sometime later on.
+	 */
+	length = cgroup_task_count(cgrp);
+	array = kvmalloc_array(length, sizeof(pid_t), GFP_KERNEL);
+	if (!array)
+		return -ENOMEM;
+	/* now, populate the array */
+	css_task_iter_start(&cgrp->self, 0, &it);
+	while ((tsk = css_task_iter_next(&it))) {
+		if (unlikely(n == length))
+			break;
+		/* get tgid or pid for procs or tasks file respectively */
+		if (type == CGROUP_FILE_PROCS)
+			pid = task_tgid_vnr(tsk);
+		else
+			pid = task_pid_vnr(tsk);
+		if (pid > 0) /* make sure to only use valid results */
+			array[n++] = pid;
+	}
+	css_task_iter_end(&it);
+	length = n;
+	/* now sort & strip out duplicates (tgids or recycled thread PIDs) */
+	sort(array, length, sizeof(pid_t), cmppid, NULL);
+	length = pidlist_uniq(array, length);
+
+	l = cgroup_pidlist_find_create(cgrp, type);
+	if (!l) {
+		kvfree(array);
+		return -ENOMEM;
+	}
+
+	/* store array, freeing old if necessary */
+	kvfree(l->list);
+	l->list = array;
+	l->length = length;
+	*lp = l;
+	return 0;
+}
+
+/*
+ * seq_file methods for the tasks/procs files. The seq_file position is the
+ * next pid to display; the seq_file iterator is a pointer to the pid
+ * in the cgroup->l->list array.
+ */
+
+static void *cgroup_pidlist_start(struct seq_file *s, loff_t *pos)
+{
+	/*
+	 * Initially we receive a position value that corresponds to
+	 * one more than the last pid shown (or 0 on the first call or
+	 * after a seek to the start). Use a binary-search to find the
+	 * next pid to display, if any
+	 */
+	struct kernfs_open_file *of = s->private;
+	struct cgroup_file_ctx *ctx = of->priv;
+	struct cgroup *cgrp = seq_css(s)->cgroup;
+	struct cgroup_pidlist *l;
+	enum cgroup_filetype type = seq_cft(s)->private;
+	int index = 0, pid = *pos;
+	int *iter, ret;
+
+	mutex_lock(&cgrp->pidlist_mutex);
+
+	/*
+	 * !NULL @ctx->procs1.pidlist indicates that this isn't the first
+	 * start() after open. If the matching pidlist is around, we can use
+	 * that. Look for it. Note that @ctx->procs1.pidlist can't be used
+	 * directly. It could already have been destroyed.
+	 */
+	if (ctx->procs1.pidlist)
+		ctx->procs1.pidlist = cgroup_pidlist_find(cgrp, type);
+
+	/*
+	 * Either this is the first start() after open or the matching
+	 * pidlist has been destroyed inbetween.  Create a new one.
+	 */
+	if (!ctx->procs1.pidlist) {
+		ret = pidlist_array_load(cgrp, type, &ctx->procs1.pidlist);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+	l = ctx->procs1.pidlist;
+
+	if (pid) {
+		int end = l->length;
+
+		while (index < end) {
+			int mid = (index + end) / 2;
+			if (l->list[mid] == pid) {
+				index = mid;
+				break;
+			} else if (l->list[mid] <= pid)
+				index = mid + 1;
+			else
+				end = mid;
+		}
+	}
+	/* If we're off the end of the array, we're done */
+	if (index >= l->length)
+		return NULL;
+	/* Update the abstract position to be the actual pid that we found */
+	iter = l->list + index;
+	*pos = *iter;
+	return iter;
+}
+
+static void cgroup_pidlist_stop(struct seq_file *s, void *v)
+{
+	struct kernfs_open_file *of = s->private;
+	struct cgroup_file_ctx *ctx = of->priv;
+	struct cgroup_pidlist *l = ctx->procs1.pidlist;
+
+	if (l)
+		mod_delayed_work(cgroup_pidlist_destroy_wq, &l->destroy_dwork,
+				 CGROUP_PIDLIST_DESTROY_DELAY);
+	mutex_unlock(&seq_css(s)->cgroup->pidlist_mutex);
+}
+
+static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos)
+{
+	struct kernfs_open_file *of = s->private;
+	struct cgroup_file_ctx *ctx = of->priv;
+	struct cgroup_pidlist *l = ctx->procs1.pidlist;
+	pid_t *p = v;
+	pid_t *end = l->list + l->length;
+	/*
+	 * Advance to the next pid in the array. If this goes off the
+	 * end, we're done
+	 */
+	p++;
+	if (p >= end) {
+		(*pos)++;
+		return NULL;
+	} else {
+		*pos = *p;
+		return p;
+	}
+}
+
+static int cgroup_pidlist_show(struct seq_file *s, void *v)
+{
+	seq_printf(s, "%d\n", *(int *)v);
+
+	return 0;
+}
+
+static ssize_t __cgroup1_procs_write(struct kernfs_open_file *of,
+				     char *buf, size_t nbytes, loff_t off,
+				     bool threadgroup)
+{
+	struct cgroup *cgrp;
+	struct task_struct *task;
+	const struct cred *cred, *tcred;
+	ssize_t ret;
+	bool locked;
+
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENODEV;
+
+	task = cgroup_procs_write_start(buf, threadgroup, &locked);
+	ret = PTR_ERR_OR_ZERO(task);
+	if (ret)
+		goto out_unlock;
+
+	/*
+	 * Even if we're attaching all tasks in the thread group, we only need
+	 * to check permissions on one of them. Check permissions using the
+	 * credentials from file open to protect against inherited fd attacks.
+	 */
+	cred = of->file->f_cred;
+	tcred = get_task_cred(task);
+	if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) &&
+	    !uid_eq(cred->euid, tcred->uid) &&
+	    !uid_eq(cred->euid, tcred->suid))
+		ret = -EACCES;
+	put_cred(tcred);
+	if (ret)
+		goto out_finish;
+
+	ret = cgroup_attach_task(cgrp, task, threadgroup);
+
+out_finish:
+	cgroup_procs_write_finish(task, locked);
+out_unlock:
+	cgroup_kn_unlock(of->kn);
+
+	return ret ?: nbytes;
+}
+
+static ssize_t cgroup1_procs_write(struct kernfs_open_file *of,
+				   char *buf, size_t nbytes, loff_t off)
+{
+	return __cgroup1_procs_write(of, buf, nbytes, off, true);
+}
+
+static ssize_t cgroup1_tasks_write(struct kernfs_open_file *of,
+				   char *buf, size_t nbytes, loff_t off)
+{
+	return __cgroup1_procs_write(of, buf, nbytes, off, false);
+}
+
+static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of,
+					  char *buf, size_t nbytes, loff_t off)
+{
+	struct cgroup *cgrp;
+	struct cgroup_file_ctx *ctx;
+
+	BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
+
+	/*
+	 * Release agent gets called with all capabilities,
+	 * require capabilities to set release agent.
+	 */
+	ctx = of->priv;
+	if ((ctx->ns->user_ns != &init_user_ns) ||
+	    !file_ns_capable(of->file, &init_user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENODEV;
+	spin_lock(&release_agent_path_lock);
+	strlcpy(cgrp->root->release_agent_path, strstrip(buf),
+		sizeof(cgrp->root->release_agent_path));
+	spin_unlock(&release_agent_path_lock);
+	cgroup_kn_unlock(of->kn);
+	return nbytes;
+}
+
+static int cgroup_release_agent_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+
+	spin_lock(&release_agent_path_lock);
+	seq_puts(seq, cgrp->root->release_agent_path);
+	spin_unlock(&release_agent_path_lock);
+	seq_putc(seq, '\n');
+	return 0;
+}
+
+static int cgroup_sane_behavior_show(struct seq_file *seq, void *v)
+{
+	seq_puts(seq, "0\n");
+	return 0;
+}
+
+static u64 cgroup_read_notify_on_release(struct cgroup_subsys_state *css,
+					 struct cftype *cft)
+{
+	return notify_on_release(css->cgroup);
+}
+
+static int cgroup_write_notify_on_release(struct cgroup_subsys_state *css,
+					  struct cftype *cft, u64 val)
+{
+	if (val)
+		set_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
+	else
+		clear_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
+	return 0;
+}
+
+static u64 cgroup_clone_children_read(struct cgroup_subsys_state *css,
+				      struct cftype *cft)
+{
+	return test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
+}
+
+static int cgroup_clone_children_write(struct cgroup_subsys_state *css,
+				       struct cftype *cft, u64 val)
+{
+	if (val)
+		set_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
+	else
+		clear_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
+	return 0;
+}
+
+/* cgroup core interface files for the legacy hierarchies */
+struct cftype cgroup1_base_files[] = {
+	{
+		.name = "cgroup.procs",
+		.seq_start = cgroup_pidlist_start,
+		.seq_next = cgroup_pidlist_next,
+		.seq_stop = cgroup_pidlist_stop,
+		.seq_show = cgroup_pidlist_show,
+		.private = CGROUP_FILE_PROCS,
+		.write = cgroup1_procs_write,
+	},
+	{
+		.name = "cgroup.clone_children",
+		.read_u64 = cgroup_clone_children_read,
+		.write_u64 = cgroup_clone_children_write,
+	},
+	{
+		.name = "cgroup.sane_behavior",
+		.flags = CFTYPE_ONLY_ON_ROOT,
+		.seq_show = cgroup_sane_behavior_show,
+	},
+	{
+		.name = "tasks",
+		.seq_start = cgroup_pidlist_start,
+		.seq_next = cgroup_pidlist_next,
+		.seq_stop = cgroup_pidlist_stop,
+		.seq_show = cgroup_pidlist_show,
+		.private = CGROUP_FILE_TASKS,
+		.write = cgroup1_tasks_write,
+	},
+	{
+		.name = "notify_on_release",
+		.read_u64 = cgroup_read_notify_on_release,
+		.write_u64 = cgroup_write_notify_on_release,
+	},
+	{
+		.name = "release_agent",
+		.flags = CFTYPE_ONLY_ON_ROOT,
+		.seq_show = cgroup_release_agent_show,
+		.write = cgroup_release_agent_write,
+		.max_write_len = PATH_MAX - 1,
+	},
+	{ }	/* terminate */
+};
+
+/* Display information about each subsystem and each hierarchy */
+int proc_cgroupstats_show(struct seq_file *m, void *v)
+{
+	struct cgroup_subsys *ss;
+	int i;
+
+	seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n");
+	/*
+	 * Grab the subsystems state racily. No need to add avenue to
+	 * cgroup_mutex contention.
+	 */
+
+	for_each_subsys(ss, i)
+		seq_printf(m, "%s\t%d\t%d\t%d\n",
+			   ss->legacy_name, ss->root->hierarchy_id,
+			   atomic_read(&ss->root->nr_cgrps),
+			   cgroup_ssid_enabled(i));
+
+	return 0;
+}
+
+/**
+ * cgroupstats_build - build and fill cgroupstats
+ * @stats: cgroupstats to fill information into
+ * @dentry: A dentry entry belonging to the cgroup for which stats have
+ * been requested.
+ *
+ * Build and fill cgroupstats so that taskstats can export it to user
+ * space.
+ *
+ * Return: %0 on success or a negative errno code on failure
+ */
+int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
+{
+	struct kernfs_node *kn = kernfs_node_from_dentry(dentry);
+	struct cgroup *cgrp;
+	struct css_task_iter it;
+	struct task_struct *tsk;
+
+	/* it should be kernfs_node belonging to cgroupfs and is a directory */
+	if (dentry->d_sb->s_type != &cgroup_fs_type || !kn ||
+	    kernfs_type(kn) != KERNFS_DIR)
+		return -EINVAL;
+
+	/*
+	 * We aren't being called from kernfs and there's no guarantee on
+	 * @kn->priv's validity.  For this and css_tryget_online_from_dir(),
+	 * @kn->priv is RCU safe.  Let's do the RCU dancing.
+	 */
+	rcu_read_lock();
+	cgrp = rcu_dereference(*(void __rcu __force **)&kn->priv);
+	if (!cgrp || !cgroup_tryget(cgrp)) {
+		rcu_read_unlock();
+		return -ENOENT;
+	}
+	rcu_read_unlock();
+
+	css_task_iter_start(&cgrp->self, 0, &it);
+	while ((tsk = css_task_iter_next(&it))) {
+		switch (READ_ONCE(tsk->__state)) {
+		case TASK_RUNNING:
+			stats->nr_running++;
+			break;
+		case TASK_INTERRUPTIBLE:
+			stats->nr_sleeping++;
+			break;
+		case TASK_UNINTERRUPTIBLE:
+			stats->nr_uninterruptible++;
+			break;
+		case TASK_STOPPED:
+			stats->nr_stopped++;
+			break;
+		default:
+			if (tsk->in_iowait)
+				stats->nr_io_wait++;
+			break;
+		}
+	}
+	css_task_iter_end(&it);
+
+	cgroup_put(cgrp);
+	return 0;
+}
+
+void cgroup1_check_for_release(struct cgroup *cgrp)
+{
+	if (notify_on_release(cgrp) && !cgroup_is_populated(cgrp) &&
+	    !css_has_online_children(&cgrp->self) && !cgroup_is_dead(cgrp))
+		schedule_work(&cgrp->release_agent_work);
+}
+
+/*
+ * Notify userspace when a cgroup is released, by running the
+ * configured release agent with the name of the cgroup (path
+ * relative to the root of cgroup file system) as the argument.
+ *
+ * Most likely, this user command will try to rmdir this cgroup.
+ *
+ * This races with the possibility that some other task will be
+ * attached to this cgroup before it is removed, or that some other
+ * user task will 'mkdir' a child cgroup of this cgroup.  That's ok.
+ * The presumed 'rmdir' will fail quietly if this cgroup is no longer
+ * unused, and this cgroup will be reprieved from its death sentence,
+ * to continue to serve a useful existence.  Next time it's released,
+ * we will get notified again, if it still has 'notify_on_release' set.
+ *
+ * The final arg to call_usermodehelper() is UMH_WAIT_EXEC, which
+ * means only wait until the task is successfully execve()'d.  The
+ * separate release agent task is forked by call_usermodehelper(),
+ * then control in this thread returns here, without waiting for the
+ * release agent task.  We don't bother to wait because the caller of
+ * this routine has no use for the exit status of the release agent
+ * task, so no sense holding our caller up for that.
+ */
+void cgroup1_release_agent(struct work_struct *work)
+{
+	struct cgroup *cgrp =
+		container_of(work, struct cgroup, release_agent_work);
+	char *pathbuf, *agentbuf;
+	char *argv[3], *envp[3];
+	int ret;
+
+	/* snoop agent path and exit early if empty */
+	if (!cgrp->root->release_agent_path[0])
+		return;
+
+	/* prepare argument buffers */
+	pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
+	agentbuf = kmalloc(PATH_MAX, GFP_KERNEL);
+	if (!pathbuf || !agentbuf)
+		goto out_free;
+
+	spin_lock(&release_agent_path_lock);
+	strlcpy(agentbuf, cgrp->root->release_agent_path, PATH_MAX);
+	spin_unlock(&release_agent_path_lock);
+	if (!agentbuf[0])
+		goto out_free;
+
+	ret = cgroup_path_ns(cgrp, pathbuf, PATH_MAX, &init_cgroup_ns);
+	if (ret < 0 || ret >= PATH_MAX)
+		goto out_free;
+
+	argv[0] = agentbuf;
+	argv[1] = pathbuf;
+	argv[2] = NULL;
+
+	/* minimal command environment */
+	envp[0] = "HOME=/";
+	envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
+	envp[2] = NULL;
+
+	call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
+out_free:
+	kfree(agentbuf);
+	kfree(pathbuf);
+}
+
+/*
+ * cgroup_rename - Only allow simple rename of directories in place.
+ */
+static int cgroup1_rename(struct kernfs_node *kn, struct kernfs_node *new_parent,
+			  const char *new_name_str)
+{
+	struct cgroup *cgrp = kn->priv;
+	int ret;
+
+	/* do not accept '\n' to prevent making /proc/<pid>/cgroup unparsable */
+	if (strchr(new_name_str, '\n'))
+		return -EINVAL;
+
+	if (kernfs_type(kn) != KERNFS_DIR)
+		return -ENOTDIR;
+	if (kn->parent != new_parent)
+		return -EIO;
+
+	/*
+	 * We're gonna grab cgroup_mutex which nests outside kernfs
+	 * active_ref.  kernfs_rename() doesn't require active_ref
+	 * protection.  Break them before grabbing cgroup_mutex.
+	 */
+	kernfs_break_active_protection(new_parent);
+	kernfs_break_active_protection(kn);
+
+	cgroup_lock();
+
+	ret = kernfs_rename(kn, new_parent, new_name_str);
+	if (!ret)
+		TRACE_CGROUP_PATH(rename, cgrp);
+
+	cgroup_unlock();
+
+	kernfs_unbreak_active_protection(kn);
+	kernfs_unbreak_active_protection(new_parent);
+	return ret;
+}
+
+static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_root)
+{
+	struct cgroup_root *root = cgroup_root_from_kf(kf_root);
+	struct cgroup_subsys *ss;
+	int ssid;
+
+	for_each_subsys(ss, ssid)
+		if (root->subsys_mask & (1 << ssid))
+			seq_show_option(seq, ss->legacy_name, NULL);
+	if (root->flags & CGRP_ROOT_NOPREFIX)
+		seq_puts(seq, ",noprefix");
+	if (root->flags & CGRP_ROOT_XATTR)
+		seq_puts(seq, ",xattr");
+	if (root->flags & CGRP_ROOT_CPUSET_V2_MODE)
+		seq_puts(seq, ",cpuset_v2_mode");
+	if (root->flags & CGRP_ROOT_FAVOR_DYNMODS)
+		seq_puts(seq, ",favordynmods");
+
+	spin_lock(&release_agent_path_lock);
+	if (strlen(root->release_agent_path))
+		seq_show_option(seq, "release_agent",
+				root->release_agent_path);
+	spin_unlock(&release_agent_path_lock);
+
+	if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags))
+		seq_puts(seq, ",clone_children");
+	if (strlen(root->name))
+		seq_show_option(seq, "name", root->name);
+	return 0;
+}
+
+enum cgroup1_param {
+	Opt_all,
+	Opt_clone_children,
+	Opt_cpuset_v2_mode,
+	Opt_name,
+	Opt_none,
+	Opt_noprefix,
+	Opt_release_agent,
+	Opt_xattr,
+	Opt_favordynmods,
+	Opt_nofavordynmods,
+};
+
+const struct fs_parameter_spec cgroup1_fs_parameters[] = {
+	fsparam_flag  ("all",		Opt_all),
+	fsparam_flag  ("clone_children", Opt_clone_children),
+	fsparam_flag  ("cpuset_v2_mode", Opt_cpuset_v2_mode),
+	fsparam_string("name",		Opt_name),
+	fsparam_flag  ("none",		Opt_none),
+	fsparam_flag  ("noprefix",	Opt_noprefix),
+	fsparam_string("release_agent",	Opt_release_agent),
+	fsparam_flag  ("xattr",		Opt_xattr),
+	fsparam_flag  ("favordynmods",	Opt_favordynmods),
+	fsparam_flag  ("nofavordynmods", Opt_nofavordynmods),
+	{}
+};
+
+int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+	struct cgroup_subsys *ss;
+	struct fs_parse_result result;
+	int opt, i;
+
+	opt = fs_parse(fc, cgroup1_fs_parameters, param, &result);
+	if (opt == -ENOPARAM) {
+		int ret;
+
+		ret = vfs_parse_fs_param_source(fc, param);
+		if (ret != -ENOPARAM)
+			return ret;
+		for_each_subsys(ss, i) {
+			if (strcmp(param->key, ss->legacy_name))
+				continue;
+			if (!cgroup_ssid_enabled(i) || cgroup1_ssid_disabled(i))
+				return invalfc(fc, "Disabled controller '%s'",
+					       param->key);
+			ctx->subsys_mask |= (1 << i);
+			return 0;
+		}
+		return invalfc(fc, "Unknown subsys name '%s'", param->key);
+	}
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_none:
+		/* Explicitly have no subsystems */
+		ctx->none = true;
+		break;
+	case Opt_all:
+		ctx->all_ss = true;
+		break;
+	case Opt_noprefix:
+		ctx->flags |= CGRP_ROOT_NOPREFIX;
+		break;
+	case Opt_clone_children:
+		ctx->cpuset_clone_children = true;
+		break;
+	case Opt_cpuset_v2_mode:
+		ctx->flags |= CGRP_ROOT_CPUSET_V2_MODE;
+		break;
+	case Opt_xattr:
+		ctx->flags |= CGRP_ROOT_XATTR;
+		break;
+	case Opt_favordynmods:
+		ctx->flags |= CGRP_ROOT_FAVOR_DYNMODS;
+		break;
+	case Opt_nofavordynmods:
+		ctx->flags &= ~CGRP_ROOT_FAVOR_DYNMODS;
+		break;
+	case Opt_release_agent:
+		/* Specifying two release agents is forbidden */
+		if (ctx->release_agent)
+			return invalfc(fc, "release_agent respecified");
+		/*
+		 * Release agent gets called with all capabilities,
+		 * require capabilities to set release agent.
+		 */
+		if ((fc->user_ns != &init_user_ns) || !capable(CAP_SYS_ADMIN))
+			return invalfc(fc, "Setting release_agent not allowed");
+		ctx->release_agent = param->string;
+		param->string = NULL;
+		break;
+	case Opt_name:
+		/* blocked by boot param? */
+		if (cgroup_no_v1_named)
+			return -ENOENT;
+		/* Can't specify an empty name */
+		if (!param->size)
+			return invalfc(fc, "Empty name");
+		if (param->size > MAX_CGROUP_ROOT_NAMELEN - 1)
+			return invalfc(fc, "Name too long");
+		/* Must match [\w.-]+ */
+		for (i = 0; i < param->size; i++) {
+			char c = param->string[i];
+			if (isalnum(c))
+				continue;
+			if ((c == '.') || (c == '-') || (c == '_'))
+				continue;
+			return invalfc(fc, "Invalid name");
+		}
+		/* Specifying two names is forbidden */
+		if (ctx->name)
+			return invalfc(fc, "name respecified");
+		ctx->name = param->string;
+		param->string = NULL;
+		break;
+	}
+	return 0;
+}
+
+static int check_cgroupfs_options(struct fs_context *fc)
+{
+	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+	u16 mask = U16_MAX;
+	u16 enabled = 0;
+	struct cgroup_subsys *ss;
+	int i;
+
+#ifdef CONFIG_CPUSETS
+	mask = ~((u16)1 << cpuset_cgrp_id);
+#endif
+	for_each_subsys(ss, i)
+		if (cgroup_ssid_enabled(i) && !cgroup1_ssid_disabled(i))
+			enabled |= 1 << i;
+
+	ctx->subsys_mask &= enabled;
+
+	/*
+	 * In absence of 'none', 'name=' and subsystem name options,
+	 * let's default to 'all'.
+	 */
+	if (!ctx->subsys_mask && !ctx->none && !ctx->name)
+		ctx->all_ss = true;
+
+	if (ctx->all_ss) {
+		/* Mutually exclusive option 'all' + subsystem name */
+		if (ctx->subsys_mask)
+			return invalfc(fc, "subsys name conflicts with all");
+		/* 'all' => select all the subsystems */
+		ctx->subsys_mask = enabled;
+	}
+
+	/*
+	 * We either have to specify by name or by subsystems. (So all
+	 * empty hierarchies must have a name).
+	 */
+	if (!ctx->subsys_mask && !ctx->name)
+		return invalfc(fc, "Need name or subsystem set");
+
+	/*
+	 * Option noprefix was introduced just for backward compatibility
+	 * with the old cpuset, so we allow noprefix only if mounting just
+	 * the cpuset subsystem.
+	 */
+	if ((ctx->flags & CGRP_ROOT_NOPREFIX) && (ctx->subsys_mask & mask))
+		return invalfc(fc, "noprefix used incorrectly");
+
+	/* Can't specify "none" and some subsystems */
+	if (ctx->subsys_mask && ctx->none)
+		return invalfc(fc, "none used incorrectly");
+
+	return 0;
+}
+
+int cgroup1_reconfigure(struct fs_context *fc)
+{
+	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+	struct kernfs_root *kf_root = kernfs_root_from_sb(fc->root->d_sb);
+	struct cgroup_root *root = cgroup_root_from_kf(kf_root);
+	int ret = 0;
+	u16 added_mask, removed_mask;
+
+	cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
+
+	/* See what subsystems are wanted */
+	ret = check_cgroupfs_options(fc);
+	if (ret)
+		goto out_unlock;
+
+	if (ctx->subsys_mask != root->subsys_mask || ctx->release_agent)
+		pr_warn("option changes via remount are deprecated (pid=%d comm=%s)\n",
+			task_tgid_nr(current), current->comm);
+
+	added_mask = ctx->subsys_mask & ~root->subsys_mask;
+	removed_mask = root->subsys_mask & ~ctx->subsys_mask;
+
+	/* Don't allow flags or name to change at remount */
+	if ((ctx->flags ^ root->flags) ||
+	    (ctx->name && strcmp(ctx->name, root->name))) {
+		errorfc(fc, "option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"",
+		       ctx->flags, ctx->name ?: "", root->flags, root->name);
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	/* remounting is not allowed for populated hierarchies */
+	if (!list_empty(&root->cgrp.self.children)) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+
+	ret = rebind_subsystems(root, added_mask);
+	if (ret)
+		goto out_unlock;
+
+	WARN_ON(rebind_subsystems(&cgrp_dfl_root, removed_mask));
+
+	if (ctx->release_agent) {
+		spin_lock(&release_agent_path_lock);
+		strcpy(root->release_agent_path, ctx->release_agent);
+		spin_unlock(&release_agent_path_lock);
+	}
+
+	trace_cgroup_remount(root);
+
+ out_unlock:
+	cgroup_unlock();
+	return ret;
+}
+
+struct kernfs_syscall_ops cgroup1_kf_syscall_ops = {
+	.rename			= cgroup1_rename,
+	.show_options		= cgroup1_show_options,
+	.mkdir			= cgroup_mkdir,
+	.rmdir			= cgroup_rmdir,
+	.show_path		= cgroup_show_path,
+};
+
+/*
+ * The guts of cgroup1 mount - find or create cgroup_root to use.
+ * Called with cgroup_mutex held; returns 0 on success, -E... on
+ * error and positive - in case when the candidate is busy dying.
+ * On success it stashes a reference to cgroup_root into given
+ * cgroup_fs_context; that reference is *NOT* counting towards the
+ * cgroup_root refcount.
+ */
+static int cgroup1_root_to_use(struct fs_context *fc)
+{
+	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+	struct cgroup_root *root;
+	struct cgroup_subsys *ss;
+	int i, ret;
+
+	/* First find the desired set of subsystems */
+	ret = check_cgroupfs_options(fc);
+	if (ret)
+		return ret;
+
+	/*
+	 * Destruction of cgroup root is asynchronous, so subsystems may
+	 * still be dying after the previous unmount.  Let's drain the
+	 * dying subsystems.  We just need to ensure that the ones
+	 * unmounted previously finish dying and don't care about new ones
+	 * starting.  Testing ref liveliness is good enough.
+	 */
+	for_each_subsys(ss, i) {
+		if (!(ctx->subsys_mask & (1 << i)) ||
+		    ss->root == &cgrp_dfl_root)
+			continue;
+
+		if (!percpu_ref_tryget_live(&ss->root->cgrp.self.refcnt))
+			return 1;	/* restart */
+		cgroup_put(&ss->root->cgrp);
+	}
+
+	for_each_root(root) {
+		bool name_match = false;
+
+		if (root == &cgrp_dfl_root)
+			continue;
+
+		/*
+		 * If we asked for a name then it must match.  Also, if
+		 * name matches but sybsys_mask doesn't, we should fail.
+		 * Remember whether name matched.
+		 */
+		if (ctx->name) {
+			if (strcmp(ctx->name, root->name))
+				continue;
+			name_match = true;
+		}
+
+		/*
+		 * If we asked for subsystems (or explicitly for no
+		 * subsystems) then they must match.
+		 */
+		if ((ctx->subsys_mask || ctx->none) &&
+		    (ctx->subsys_mask != root->subsys_mask)) {
+			if (!name_match)
+				continue;
+			return -EBUSY;
+		}
+
+		if (root->flags ^ ctx->flags)
+			pr_warn("new mount options do not match the existing superblock, will be ignored\n");
+
+		ctx->root = root;
+		return 0;
+	}
+
+	/*
+	 * No such thing, create a new one.  name= matching without subsys
+	 * specification is allowed for already existing hierarchies but we
+	 * can't create new one without subsys specification.
+	 */
+	if (!ctx->subsys_mask && !ctx->none)
+		return invalfc(fc, "No subsys list or none specified");
+
+	/* Hierarchies may only be created in the initial cgroup namespace. */
+	if (ctx->ns != &init_cgroup_ns)
+		return -EPERM;
+
+	root = kzalloc(sizeof(*root), GFP_KERNEL);
+	if (!root)
+		return -ENOMEM;
+
+	ctx->root = root;
+	init_cgroup_root(ctx);
+
+	ret = cgroup_setup_root(root, ctx->subsys_mask);
+	if (!ret)
+		cgroup_favor_dynmods(root, ctx->flags & CGRP_ROOT_FAVOR_DYNMODS);
+	else
+		cgroup_free_root(root);
+
+	return ret;
+}
+
+int cgroup1_get_tree(struct fs_context *fc)
+{
+	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+	int ret;
+
+	/* Check if the caller has permission to mount. */
+	if (!ns_capable(ctx->ns->user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
+
+	ret = cgroup1_root_to_use(fc);
+	if (!ret && !percpu_ref_tryget_live(&ctx->root->cgrp.self.refcnt))
+		ret = 1;	/* restart */
+
+	cgroup_unlock();
+
+	if (!ret)
+		ret = cgroup_do_get_tree(fc);
+
+	if (!ret && percpu_ref_is_dying(&ctx->root->cgrp.self.refcnt)) {
+		fc_drop_locked(fc);
+		ret = 1;
+	}
+
+	if (unlikely(ret > 0)) {
+		msleep(10);
+		return restart_syscall();
+	}
+	return ret;
+}
+
+static int __init cgroup1_wq_init(void)
+{
+	/*
+	 * Used to destroy pidlists and separate to serve as flush domain.
+	 * Cap @max_active to 1 too.
+	 */
+	cgroup_pidlist_destroy_wq = alloc_workqueue("cgroup_pidlist_destroy",
+						    0, 1);
+	BUG_ON(!cgroup_pidlist_destroy_wq);
+	return 0;
+}
+core_initcall(cgroup1_wq_init);
+
+static int __init cgroup_no_v1(char *str)
+{
+	struct cgroup_subsys *ss;
+	char *token;
+	int i;
+
+	while ((token = strsep(&str, ",")) != NULL) {
+		if (!*token)
+			continue;
+
+		if (!strcmp(token, "all")) {
+			cgroup_no_v1_mask = U16_MAX;
+			continue;
+		}
+
+		if (!strcmp(token, "named")) {
+			cgroup_no_v1_named = true;
+			continue;
+		}
+
+		for_each_subsys(ss, i) {
+			if (strcmp(token, ss->name) &&
+			    strcmp(token, ss->legacy_name))
+				continue;
+
+			cgroup_no_v1_mask |= 1 << i;
+		}
+	}
+	return 1;
+}
+__setup("cgroup_no_v1=", cgroup_no_v1);
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
new file mode 100644
index 000000000..97ecca433
--- /dev/null
+++ b/kernel/cgroup/cgroup.c
@@ -0,0 +1,7074 @@
+/*
+ *  Generic process-grouping system.
+ *
+ *  Based originally on the cpuset system, extracted by Paul Menage
+ *  Copyright (C) 2006 Google, Inc
+ *
+ *  Notifications support
+ *  Copyright (C) 2009 Nokia Corporation
+ *  Author: Kirill A. Shutemov
+ *
+ *  Copyright notices from the original cpuset code:
+ *  --------------------------------------------------
+ *  Copyright (C) 2003 BULL SA.
+ *  Copyright (C) 2004-2006 Silicon Graphics, Inc.
+ *
+ *  Portions derived from Patrick Mochel's sysfs code.
+ *  sysfs is Copyright (c) 2001-3 Patrick Mochel
+ *
+ *  2003-10-10 Written by Simon Derr.
+ *  2003-10-22 Updates by Stephen Hemminger.
+ *  2004 May-July Rework by Paul Jackson.
+ *  ---------------------------------------------------
+ *
+ *  This file is subject to the terms and conditions of the GNU General Public
+ *  License.  See the file COPYING in the main directory of the Linux
+ *  distribution for more details.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include "cgroup-internal.h"
+
+#include <linux/bpf-cgroup.h>
+#include <linux/cred.h>
+#include <linux/errno.h>
+#include <linux/init_task.h>
+#include <linux/kernel.h>
+#include <linux/magic.h>
+#include <linux/mutex.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/proc_fs.h>
+#include <linux/rcupdate.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/percpu-rwsem.h>
+#include <linux/string.h>
+#include <linux/hashtable.h>
+#include <linux/idr.h>
+#include <linux/kthread.h>
+#include <linux/atomic.h>
+#include <linux/cpuset.h>
+#include <linux/proc_ns.h>
+#include <linux/nsproxy.h>
+#include <linux/file.h>
+#include <linux/fs_parser.h>
+#include <linux/sched/cputime.h>
+#include <linux/sched/deadline.h>
+#include <linux/psi.h>
+#include <net/sock.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/cgroup.h>
+
+#define CGROUP_FILE_NAME_MAX		(MAX_CGROUP_TYPE_NAMELEN +	\
+					 MAX_CFTYPE_NAME + 2)
+/* let's not notify more than 100 times per second */
+#define CGROUP_FILE_NOTIFY_MIN_INTV	DIV_ROUND_UP(HZ, 100)
+
+/*
+ * To avoid confusing the compiler (and generating warnings) with code
+ * that attempts to access what would be a 0-element array (i.e. sized
+ * to a potentially empty array when CGROUP_SUBSYS_COUNT == 0), this
+ * constant expression can be added.
+ */
+#define CGROUP_HAS_SUBSYS_CONFIG	(CGROUP_SUBSYS_COUNT > 0)
+
+/*
+ * cgroup_mutex is the master lock.  Any modification to cgroup or its
+ * hierarchy must be performed while holding it.
+ *
+ * css_set_lock protects task->cgroups pointer, the list of css_set
+ * objects, and the chain of tasks off each css_set.
+ *
+ * These locks are exported if CONFIG_PROVE_RCU so that accessors in
+ * cgroup.h can use them for lockdep annotations.
+ */
+DEFINE_MUTEX(cgroup_mutex);
+DEFINE_SPINLOCK(css_set_lock);
+
+#ifdef CONFIG_PROVE_RCU
+EXPORT_SYMBOL_GPL(cgroup_mutex);
+EXPORT_SYMBOL_GPL(css_set_lock);
+#endif
+
+DEFINE_SPINLOCK(trace_cgroup_path_lock);
+char trace_cgroup_path[TRACE_CGROUP_PATH_LEN];
+static bool cgroup_debug __read_mostly;
+
+/*
+ * Protects cgroup_idr and css_idr so that IDs can be released without
+ * grabbing cgroup_mutex.
+ */
+static DEFINE_SPINLOCK(cgroup_idr_lock);
+
+/*
+ * Protects cgroup_file->kn for !self csses.  It synchronizes notifications
+ * against file removal/re-creation across css hiding.
+ */
+static DEFINE_SPINLOCK(cgroup_file_kn_lock);
+
+DEFINE_PERCPU_RWSEM(cgroup_threadgroup_rwsem);
+
+#define cgroup_assert_mutex_or_rcu_locked()				\
+	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
+			   !lockdep_is_held(&cgroup_mutex),		\
+			   "cgroup_mutex or RCU read lock required");
+
+/*
+ * cgroup destruction makes heavy use of work items and there can be a lot
+ * of concurrent destructions.  Use a separate workqueue so that cgroup
+ * destruction work items don't end up filling up max_active of system_wq
+ * which may lead to deadlock.
+ */
+static struct workqueue_struct *cgroup_destroy_wq;
+
+/* generate an array of cgroup subsystem pointers */
+#define SUBSYS(_x) [_x ## _cgrp_id] = &_x ## _cgrp_subsys,
+struct cgroup_subsys *cgroup_subsys[] = {
+#include <linux/cgroup_subsys.h>
+};
+#undef SUBSYS
+
+/* array of cgroup subsystem names */
+#define SUBSYS(_x) [_x ## _cgrp_id] = #_x,
+static const char *cgroup_subsys_name[] = {
+#include <linux/cgroup_subsys.h>
+};
+#undef SUBSYS
+
+/* array of static_keys for cgroup_subsys_enabled() and cgroup_subsys_on_dfl() */
+#define SUBSYS(_x)								\
+	DEFINE_STATIC_KEY_TRUE(_x ## _cgrp_subsys_enabled_key);			\
+	DEFINE_STATIC_KEY_TRUE(_x ## _cgrp_subsys_on_dfl_key);			\
+	EXPORT_SYMBOL_GPL(_x ## _cgrp_subsys_enabled_key);			\
+	EXPORT_SYMBOL_GPL(_x ## _cgrp_subsys_on_dfl_key);
+#include <linux/cgroup_subsys.h>
+#undef SUBSYS
+
+#define SUBSYS(_x) [_x ## _cgrp_id] = &_x ## _cgrp_subsys_enabled_key,
+static struct static_key_true *cgroup_subsys_enabled_key[] = {
+#include <linux/cgroup_subsys.h>
+};
+#undef SUBSYS
+
+#define SUBSYS(_x) [_x ## _cgrp_id] = &_x ## _cgrp_subsys_on_dfl_key,
+static struct static_key_true *cgroup_subsys_on_dfl_key[] = {
+#include <linux/cgroup_subsys.h>
+};
+#undef SUBSYS
+
+static DEFINE_PER_CPU(struct cgroup_rstat_cpu, cgrp_dfl_root_rstat_cpu);
+
+/* the default hierarchy */
+struct cgroup_root cgrp_dfl_root = { .cgrp.rstat_cpu = &cgrp_dfl_root_rstat_cpu };
+EXPORT_SYMBOL_GPL(cgrp_dfl_root);
+
+/*
+ * The default hierarchy always exists but is hidden until mounted for the
+ * first time.  This is for backward compatibility.
+ */
+static bool cgrp_dfl_visible;
+
+/* some controllers are not supported in the default hierarchy */
+static u16 cgrp_dfl_inhibit_ss_mask;
+
+/* some controllers are implicitly enabled on the default hierarchy */
+static u16 cgrp_dfl_implicit_ss_mask;
+
+/* some controllers can be threaded on the default hierarchy */
+static u16 cgrp_dfl_threaded_ss_mask;
+
+/* The list of hierarchy roots */
+LIST_HEAD(cgroup_roots);
+static int cgroup_root_count;
+
+/* hierarchy ID allocation and mapping, protected by cgroup_mutex */
+static DEFINE_IDR(cgroup_hierarchy_idr);
+
+/*
+ * Assign a monotonically increasing serial number to csses.  It guarantees
+ * cgroups with bigger numbers are newer than those with smaller numbers.
+ * Also, as csses are always appended to the parent's ->children list, it
+ * guarantees that sibling csses are always sorted in the ascending serial
+ * number order on the list.  Protected by cgroup_mutex.
+ */
+static u64 css_serial_nr_next = 1;
+
+/*
+ * These bitmasks identify subsystems with specific features to avoid
+ * having to do iterative checks repeatedly.
+ */
+static u16 have_fork_callback __read_mostly;
+static u16 have_exit_callback __read_mostly;
+static u16 have_release_callback __read_mostly;
+static u16 have_canfork_callback __read_mostly;
+
+/* cgroup namespace for init task */
+struct cgroup_namespace init_cgroup_ns = {
+	.ns.count	= REFCOUNT_INIT(2),
+	.user_ns	= &init_user_ns,
+	.ns.ops		= &cgroupns_operations,
+	.ns.inum	= PROC_CGROUP_INIT_INO,
+	.root_cset	= &init_css_set,
+};
+
+static struct file_system_type cgroup2_fs_type;
+static struct cftype cgroup_base_files[];
+static struct cftype cgroup_psi_files[];
+
+/* cgroup optional features */
+enum cgroup_opt_features {
+#ifdef CONFIG_PSI
+	OPT_FEATURE_PRESSURE,
+#endif
+	OPT_FEATURE_COUNT
+};
+
+static const char *cgroup_opt_feature_names[OPT_FEATURE_COUNT] = {
+#ifdef CONFIG_PSI
+	"pressure",
+#endif
+};
+
+static u16 cgroup_feature_disable_mask __read_mostly;
+
+static int cgroup_apply_control(struct cgroup *cgrp);
+static void cgroup_finalize_control(struct cgroup *cgrp, int ret);
+static void css_task_iter_skip(struct css_task_iter *it,
+			       struct task_struct *task);
+static int cgroup_destroy_locked(struct cgroup *cgrp);
+static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
+					      struct cgroup_subsys *ss);
+static void css_release(struct percpu_ref *ref);
+static void kill_css(struct cgroup_subsys_state *css);
+static int cgroup_addrm_files(struct cgroup_subsys_state *css,
+			      struct cgroup *cgrp, struct cftype cfts[],
+			      bool is_add);
+
+/**
+ * cgroup_ssid_enabled - cgroup subsys enabled test by subsys ID
+ * @ssid: subsys ID of interest
+ *
+ * cgroup_subsys_enabled() can only be used with literal subsys names which
+ * is fine for individual subsystems but unsuitable for cgroup core.  This
+ * is slower static_key_enabled() based test indexed by @ssid.
+ */
+bool cgroup_ssid_enabled(int ssid)
+{
+	if (!CGROUP_HAS_SUBSYS_CONFIG)
+		return false;
+
+	return static_key_enabled(cgroup_subsys_enabled_key[ssid]);
+}
+
+/**
+ * cgroup_on_dfl - test whether a cgroup is on the default hierarchy
+ * @cgrp: the cgroup of interest
+ *
+ * The default hierarchy is the v2 interface of cgroup and this function
+ * can be used to test whether a cgroup is on the default hierarchy for
+ * cases where a subsystem should behave differently depending on the
+ * interface version.
+ *
+ * List of changed behaviors:
+ *
+ * - Mount options "noprefix", "xattr", "clone_children", "release_agent"
+ *   and "name" are disallowed.
+ *
+ * - When mounting an existing superblock, mount options should match.
+ *
+ * - rename(2) is disallowed.
+ *
+ * - "tasks" is removed.  Everything should be at process granularity.  Use
+ *   "cgroup.procs" instead.
+ *
+ * - "cgroup.procs" is not sorted.  pids will be unique unless they got
+ *   recycled in-between reads.
+ *
+ * - "release_agent" and "notify_on_release" are removed.  Replacement
+ *   notification mechanism will be implemented.
+ *
+ * - "cgroup.clone_children" is removed.
+ *
+ * - "cgroup.subtree_populated" is available.  Its value is 0 if the cgroup
+ *   and its descendants contain no task; otherwise, 1.  The file also
+ *   generates kernfs notification which can be monitored through poll and
+ *   [di]notify when the value of the file changes.
+ *
+ * - cpuset: tasks will be kept in empty cpusets when hotplug happens and
+ *   take masks of ancestors with non-empty cpus/mems, instead of being
+ *   moved to an ancestor.
+ *
+ * - cpuset: a task can be moved into an empty cpuset, and again it takes
+ *   masks of ancestors.
+ *
+ * - blkcg: blk-throttle becomes properly hierarchical.
+ *
+ * - debug: disallowed on the default hierarchy.
+ */
+bool cgroup_on_dfl(const struct cgroup *cgrp)
+{
+	return cgrp->root == &cgrp_dfl_root;
+}
+
+/* IDR wrappers which synchronize using cgroup_idr_lock */
+static int cgroup_idr_alloc(struct idr *idr, void *ptr, int start, int end,
+			    gfp_t gfp_mask)
+{
+	int ret;
+
+	idr_preload(gfp_mask);
+	spin_lock_bh(&cgroup_idr_lock);
+	ret = idr_alloc(idr, ptr, start, end, gfp_mask & ~__GFP_DIRECT_RECLAIM);
+	spin_unlock_bh(&cgroup_idr_lock);
+	idr_preload_end();
+	return ret;
+}
+
+static void *cgroup_idr_replace(struct idr *idr, void *ptr, int id)
+{
+	void *ret;
+
+	spin_lock_bh(&cgroup_idr_lock);
+	ret = idr_replace(idr, ptr, id);
+	spin_unlock_bh(&cgroup_idr_lock);
+	return ret;
+}
+
+static void cgroup_idr_remove(struct idr *idr, int id)
+{
+	spin_lock_bh(&cgroup_idr_lock);
+	idr_remove(idr, id);
+	spin_unlock_bh(&cgroup_idr_lock);
+}
+
+static bool cgroup_has_tasks(struct cgroup *cgrp)
+{
+	return cgrp->nr_populated_csets;
+}
+
+bool cgroup_is_threaded(struct cgroup *cgrp)
+{
+	return cgrp->dom_cgrp != cgrp;
+}
+
+/* can @cgrp host both domain and threaded children? */
+static bool cgroup_is_mixable(struct cgroup *cgrp)
+{
+	/*
+	 * Root isn't under domain level resource control exempting it from
+	 * the no-internal-process constraint, so it can serve as a thread
+	 * root and a parent of resource domains at the same time.
+	 */
+	return !cgroup_parent(cgrp);
+}
+
+/* can @cgrp become a thread root? Should always be true for a thread root */
+static bool cgroup_can_be_thread_root(struct cgroup *cgrp)
+{
+	/* mixables don't care */
+	if (cgroup_is_mixable(cgrp))
+		return true;
+
+	/* domain roots can't be nested under threaded */
+	if (cgroup_is_threaded(cgrp))
+		return false;
+
+	/* can only have either domain or threaded children */
+	if (cgrp->nr_populated_domain_children)
+		return false;
+
+	/* and no domain controllers can be enabled */
+	if (cgrp->subtree_control & ~cgrp_dfl_threaded_ss_mask)
+		return false;
+
+	return true;
+}
+
+/* is @cgrp root of a threaded subtree? */
+bool cgroup_is_thread_root(struct cgroup *cgrp)
+{
+	/* thread root should be a domain */
+	if (cgroup_is_threaded(cgrp))
+		return false;
+
+	/* a domain w/ threaded children is a thread root */
+	if (cgrp->nr_threaded_children)
+		return true;
+
+	/*
+	 * A domain which has tasks and explicit threaded controllers
+	 * enabled is a thread root.
+	 */
+	if (cgroup_has_tasks(cgrp) &&
+	    (cgrp->subtree_control & cgrp_dfl_threaded_ss_mask))
+		return true;
+
+	return false;
+}
+
+/* a domain which isn't connected to the root w/o brekage can't be used */
+static bool cgroup_is_valid_domain(struct cgroup *cgrp)
+{
+	/* the cgroup itself can be a thread root */
+	if (cgroup_is_threaded(cgrp))
+		return false;
+
+	/* but the ancestors can't be unless mixable */
+	while ((cgrp = cgroup_parent(cgrp))) {
+		if (!cgroup_is_mixable(cgrp) && cgroup_is_thread_root(cgrp))
+			return false;
+		if (cgroup_is_threaded(cgrp))
+			return false;
+	}
+
+	return true;
+}
+
+/* subsystems visibly enabled on a cgroup */
+static u16 cgroup_control(struct cgroup *cgrp)
+{
+	struct cgroup *parent = cgroup_parent(cgrp);
+	u16 root_ss_mask = cgrp->root->subsys_mask;
+
+	if (parent) {
+		u16 ss_mask = parent->subtree_control;
+
+		/* threaded cgroups can only have threaded controllers */
+		if (cgroup_is_threaded(cgrp))
+			ss_mask &= cgrp_dfl_threaded_ss_mask;
+		return ss_mask;
+	}
+
+	if (cgroup_on_dfl(cgrp))
+		root_ss_mask &= ~(cgrp_dfl_inhibit_ss_mask |
+				  cgrp_dfl_implicit_ss_mask);
+	return root_ss_mask;
+}
+
+/* subsystems enabled on a cgroup */
+static u16 cgroup_ss_mask(struct cgroup *cgrp)
+{
+	struct cgroup *parent = cgroup_parent(cgrp);
+
+	if (parent) {
+		u16 ss_mask = parent->subtree_ss_mask;
+
+		/* threaded cgroups can only have threaded controllers */
+		if (cgroup_is_threaded(cgrp))
+			ss_mask &= cgrp_dfl_threaded_ss_mask;
+		return ss_mask;
+	}
+
+	return cgrp->root->subsys_mask;
+}
+
+/**
+ * cgroup_css - obtain a cgroup's css for the specified subsystem
+ * @cgrp: the cgroup of interest
+ * @ss: the subsystem of interest (%NULL returns @cgrp->self)
+ *
+ * Return @cgrp's css (cgroup_subsys_state) associated with @ss.  This
+ * function must be called either under cgroup_mutex or rcu_read_lock() and
+ * the caller is responsible for pinning the returned css if it wants to
+ * keep accessing it outside the said locks.  This function may return
+ * %NULL if @cgrp doesn't have @subsys_id enabled.
+ */
+static struct cgroup_subsys_state *cgroup_css(struct cgroup *cgrp,
+					      struct cgroup_subsys *ss)
+{
+	if (CGROUP_HAS_SUBSYS_CONFIG && ss)
+		return rcu_dereference_check(cgrp->subsys[ss->id],
+					lockdep_is_held(&cgroup_mutex));
+	else
+		return &cgrp->self;
+}
+
+/**
+ * cgroup_tryget_css - try to get a cgroup's css for the specified subsystem
+ * @cgrp: the cgroup of interest
+ * @ss: the subsystem of interest
+ *
+ * Find and get @cgrp's css associated with @ss.  If the css doesn't exist
+ * or is offline, %NULL is returned.
+ */
+static struct cgroup_subsys_state *cgroup_tryget_css(struct cgroup *cgrp,
+						     struct cgroup_subsys *ss)
+{
+	struct cgroup_subsys_state *css;
+
+	rcu_read_lock();
+	css = cgroup_css(cgrp, ss);
+	if (css && !css_tryget_online(css))
+		css = NULL;
+	rcu_read_unlock();
+
+	return css;
+}
+
+/**
+ * cgroup_e_css_by_mask - obtain a cgroup's effective css for the specified ss
+ * @cgrp: the cgroup of interest
+ * @ss: the subsystem of interest (%NULL returns @cgrp->self)
+ *
+ * Similar to cgroup_css() but returns the effective css, which is defined
+ * as the matching css of the nearest ancestor including self which has @ss
+ * enabled.  If @ss is associated with the hierarchy @cgrp is on, this
+ * function is guaranteed to return non-NULL css.
+ */
+static struct cgroup_subsys_state *cgroup_e_css_by_mask(struct cgroup *cgrp,
+							struct cgroup_subsys *ss)
+{
+	lockdep_assert_held(&cgroup_mutex);
+
+	if (!ss)
+		return &cgrp->self;
+
+	/*
+	 * This function is used while updating css associations and thus
+	 * can't test the csses directly.  Test ss_mask.
+	 */
+	while (!(cgroup_ss_mask(cgrp) & (1 << ss->id))) {
+		cgrp = cgroup_parent(cgrp);
+		if (!cgrp)
+			return NULL;
+	}
+
+	return cgroup_css(cgrp, ss);
+}
+
+/**
+ * cgroup_e_css - obtain a cgroup's effective css for the specified subsystem
+ * @cgrp: the cgroup of interest
+ * @ss: the subsystem of interest
+ *
+ * Find and get the effective css of @cgrp for @ss.  The effective css is
+ * defined as the matching css of the nearest ancestor including self which
+ * has @ss enabled.  If @ss is not mounted on the hierarchy @cgrp is on,
+ * the root css is returned, so this function always returns a valid css.
+ *
+ * The returned css is not guaranteed to be online, and therefore it is the
+ * callers responsibility to try get a reference for it.
+ */
+struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgrp,
+					 struct cgroup_subsys *ss)
+{
+	struct cgroup_subsys_state *css;
+
+	if (!CGROUP_HAS_SUBSYS_CONFIG)
+		return NULL;
+
+	do {
+		css = cgroup_css(cgrp, ss);
+
+		if (css)
+			return css;
+		cgrp = cgroup_parent(cgrp);
+	} while (cgrp);
+
+	return init_css_set.subsys[ss->id];
+}
+
+/**
+ * cgroup_get_e_css - get a cgroup's effective css for the specified subsystem
+ * @cgrp: the cgroup of interest
+ * @ss: the subsystem of interest
+ *
+ * Find and get the effective css of @cgrp for @ss.  The effective css is
+ * defined as the matching css of the nearest ancestor including self which
+ * has @ss enabled.  If @ss is not mounted on the hierarchy @cgrp is on,
+ * the root css is returned, so this function always returns a valid css.
+ * The returned css must be put using css_put().
+ */
+struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgrp,
+					     struct cgroup_subsys *ss)
+{
+	struct cgroup_subsys_state *css;
+
+	if (!CGROUP_HAS_SUBSYS_CONFIG)
+		return NULL;
+
+	rcu_read_lock();
+
+	do {
+		css = cgroup_css(cgrp, ss);
+
+		if (css && css_tryget_online(css))
+			goto out_unlock;
+		cgrp = cgroup_parent(cgrp);
+	} while (cgrp);
+
+	css = init_css_set.subsys[ss->id];
+	css_get(css);
+out_unlock:
+	rcu_read_unlock();
+	return css;
+}
+EXPORT_SYMBOL_GPL(cgroup_get_e_css);
+
+static void cgroup_get_live(struct cgroup *cgrp)
+{
+	WARN_ON_ONCE(cgroup_is_dead(cgrp));
+	css_get(&cgrp->self);
+}
+
+/**
+ * __cgroup_task_count - count the number of tasks in a cgroup. The caller
+ * is responsible for taking the css_set_lock.
+ * @cgrp: the cgroup in question
+ */
+int __cgroup_task_count(const struct cgroup *cgrp)
+{
+	int count = 0;
+	struct cgrp_cset_link *link;
+
+	lockdep_assert_held(&css_set_lock);
+
+	list_for_each_entry(link, &cgrp->cset_links, cset_link)
+		count += link->cset->nr_tasks;
+
+	return count;
+}
+
+/**
+ * cgroup_task_count - count the number of tasks in a cgroup.
+ * @cgrp: the cgroup in question
+ */
+int cgroup_task_count(const struct cgroup *cgrp)
+{
+	int count;
+
+	spin_lock_irq(&css_set_lock);
+	count = __cgroup_task_count(cgrp);
+	spin_unlock_irq(&css_set_lock);
+
+	return count;
+}
+
+struct cgroup_subsys_state *of_css(struct kernfs_open_file *of)
+{
+	struct cgroup *cgrp = of->kn->parent->priv;
+	struct cftype *cft = of_cft(of);
+
+	/*
+	 * This is open and unprotected implementation of cgroup_css().
+	 * seq_css() is only called from a kernfs file operation which has
+	 * an active reference on the file.  Because all the subsystem
+	 * files are drained before a css is disassociated with a cgroup,
+	 * the matching css from the cgroup's subsys table is guaranteed to
+	 * be and stay valid until the enclosing operation is complete.
+	 */
+	if (CGROUP_HAS_SUBSYS_CONFIG && cft->ss)
+		return rcu_dereference_raw(cgrp->subsys[cft->ss->id]);
+	else
+		return &cgrp->self;
+}
+EXPORT_SYMBOL_GPL(of_css);
+
+/**
+ * for_each_css - iterate all css's of a cgroup
+ * @css: the iteration cursor
+ * @ssid: the index of the subsystem, CGROUP_SUBSYS_COUNT after reaching the end
+ * @cgrp: the target cgroup to iterate css's of
+ *
+ * Should be called under cgroup_[tree_]mutex.
+ */
+#define for_each_css(css, ssid, cgrp)					\
+	for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT; (ssid)++)	\
+		if (!((css) = rcu_dereference_check(			\
+				(cgrp)->subsys[(ssid)],			\
+				lockdep_is_held(&cgroup_mutex)))) { }	\
+		else
+
+/**
+ * for_each_e_css - iterate all effective css's of a cgroup
+ * @css: the iteration cursor
+ * @ssid: the index of the subsystem, CGROUP_SUBSYS_COUNT after reaching the end
+ * @cgrp: the target cgroup to iterate css's of
+ *
+ * Should be called under cgroup_[tree_]mutex.
+ */
+#define for_each_e_css(css, ssid, cgrp)					    \
+	for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT; (ssid)++)	    \
+		if (!((css) = cgroup_e_css_by_mask(cgrp,		    \
+						   cgroup_subsys[(ssid)]))) \
+			;						    \
+		else
+
+/**
+ * do_each_subsys_mask - filter for_each_subsys with a bitmask
+ * @ss: the iteration cursor
+ * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
+ * @ss_mask: the bitmask
+ *
+ * The block will only run for cases where the ssid-th bit (1 << ssid) of
+ * @ss_mask is set.
+ */
+#define do_each_subsys_mask(ss, ssid, ss_mask) do {			\
+	unsigned long __ss_mask = (ss_mask);				\
+	if (!CGROUP_HAS_SUBSYS_CONFIG) {				\
+		(ssid) = 0;						\
+		break;							\
+	}								\
+	for_each_set_bit(ssid, &__ss_mask, CGROUP_SUBSYS_COUNT) {	\
+		(ss) = cgroup_subsys[ssid];				\
+		{
+
+#define while_each_subsys_mask()					\
+		}							\
+	}								\
+} while (false)
+
+/* iterate over child cgrps, lock should be held throughout iteration */
+#define cgroup_for_each_live_child(child, cgrp)				\
+	list_for_each_entry((child), &(cgrp)->self.children, self.sibling) \
+		if (({ lockdep_assert_held(&cgroup_mutex);		\
+		       cgroup_is_dead(child); }))			\
+			;						\
+		else
+
+/* walk live descendants in pre order */
+#define cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp)		\
+	css_for_each_descendant_pre((d_css), cgroup_css((cgrp), NULL))	\
+		if (({ lockdep_assert_held(&cgroup_mutex);		\
+		       (dsct) = (d_css)->cgroup;			\
+		       cgroup_is_dead(dsct); }))			\
+			;						\
+		else
+
+/* walk live descendants in postorder */
+#define cgroup_for_each_live_descendant_post(dsct, d_css, cgrp)		\
+	css_for_each_descendant_post((d_css), cgroup_css((cgrp), NULL))	\
+		if (({ lockdep_assert_held(&cgroup_mutex);		\
+		       (dsct) = (d_css)->cgroup;			\
+		       cgroup_is_dead(dsct); }))			\
+			;						\
+		else
+
+/*
+ * The default css_set - used by init and its children prior to any
+ * hierarchies being mounted. It contains a pointer to the root state
+ * for each subsystem. Also used to anchor the list of css_sets. Not
+ * reference-counted, to improve performance when child cgroups
+ * haven't been created.
+ */
+struct css_set init_css_set = {
+	.refcount		= REFCOUNT_INIT(1),
+	.dom_cset		= &init_css_set,
+	.tasks			= LIST_HEAD_INIT(init_css_set.tasks),
+	.mg_tasks		= LIST_HEAD_INIT(init_css_set.mg_tasks),
+	.dying_tasks		= LIST_HEAD_INIT(init_css_set.dying_tasks),
+	.task_iters		= LIST_HEAD_INIT(init_css_set.task_iters),
+	.threaded_csets		= LIST_HEAD_INIT(init_css_set.threaded_csets),
+	.cgrp_links		= LIST_HEAD_INIT(init_css_set.cgrp_links),
+	.mg_src_preload_node	= LIST_HEAD_INIT(init_css_set.mg_src_preload_node),
+	.mg_dst_preload_node	= LIST_HEAD_INIT(init_css_set.mg_dst_preload_node),
+	.mg_node		= LIST_HEAD_INIT(init_css_set.mg_node),
+
+	/*
+	 * The following field is re-initialized when this cset gets linked
+	 * in cgroup_init().  However, let's initialize the field
+	 * statically too so that the default cgroup can be accessed safely
+	 * early during boot.
+	 */
+	.dfl_cgrp		= &cgrp_dfl_root.cgrp,
+};
+
+static int css_set_count	= 1;	/* 1 for init_css_set */
+
+static bool css_set_threaded(struct css_set *cset)
+{
+	return cset->dom_cset != cset;
+}
+
+/**
+ * css_set_populated - does a css_set contain any tasks?
+ * @cset: target css_set
+ *
+ * css_set_populated() should be the same as !!cset->nr_tasks at steady
+ * state. However, css_set_populated() can be called while a task is being
+ * added to or removed from the linked list before the nr_tasks is
+ * properly updated. Hence, we can't just look at ->nr_tasks here.
+ */
+static bool css_set_populated(struct css_set *cset)
+{
+	lockdep_assert_held(&css_set_lock);
+
+	return !list_empty(&cset->tasks) || !list_empty(&cset->mg_tasks);
+}
+
+/**
+ * cgroup_update_populated - update the populated count of a cgroup
+ * @cgrp: the target cgroup
+ * @populated: inc or dec populated count
+ *
+ * One of the css_sets associated with @cgrp is either getting its first
+ * task or losing the last.  Update @cgrp->nr_populated_* accordingly.  The
+ * count is propagated towards root so that a given cgroup's
+ * nr_populated_children is zero iff none of its descendants contain any
+ * tasks.
+ *
+ * @cgrp's interface file "cgroup.populated" is zero if both
+ * @cgrp->nr_populated_csets and @cgrp->nr_populated_children are zero and
+ * 1 otherwise.  When the sum changes from or to zero, userland is notified
+ * that the content of the interface file has changed.  This can be used to
+ * detect when @cgrp and its descendants become populated or empty.
+ */
+static void cgroup_update_populated(struct cgroup *cgrp, bool populated)
+{
+	struct cgroup *child = NULL;
+	int adj = populated ? 1 : -1;
+
+	lockdep_assert_held(&css_set_lock);
+
+	do {
+		bool was_populated = cgroup_is_populated(cgrp);
+
+		if (!child) {
+			cgrp->nr_populated_csets += adj;
+		} else {
+			if (cgroup_is_threaded(child))
+				cgrp->nr_populated_threaded_children += adj;
+			else
+				cgrp->nr_populated_domain_children += adj;
+		}
+
+		if (was_populated == cgroup_is_populated(cgrp))
+			break;
+
+		cgroup1_check_for_release(cgrp);
+		TRACE_CGROUP_PATH(notify_populated, cgrp,
+				  cgroup_is_populated(cgrp));
+		cgroup_file_notify(&cgrp->events_file);
+
+		child = cgrp;
+		cgrp = cgroup_parent(cgrp);
+	} while (cgrp);
+}
+
+/**
+ * css_set_update_populated - update populated state of a css_set
+ * @cset: target css_set
+ * @populated: whether @cset is populated or depopulated
+ *
+ * @cset is either getting the first task or losing the last.  Update the
+ * populated counters of all associated cgroups accordingly.
+ */
+static void css_set_update_populated(struct css_set *cset, bool populated)
+{
+	struct cgrp_cset_link *link;
+
+	lockdep_assert_held(&css_set_lock);
+
+	list_for_each_entry(link, &cset->cgrp_links, cgrp_link)
+		cgroup_update_populated(link->cgrp, populated);
+}
+
+/*
+ * @task is leaving, advance task iterators which are pointing to it so
+ * that they can resume at the next position.  Advancing an iterator might
+ * remove it from the list, use safe walk.  See css_task_iter_skip() for
+ * details.
+ */
+static void css_set_skip_task_iters(struct css_set *cset,
+				    struct task_struct *task)
+{
+	struct css_task_iter *it, *pos;
+
+	list_for_each_entry_safe(it, pos, &cset->task_iters, iters_node)
+		css_task_iter_skip(it, task);
+}
+
+/**
+ * css_set_move_task - move a task from one css_set to another
+ * @task: task being moved
+ * @from_cset: css_set @task currently belongs to (may be NULL)
+ * @to_cset: new css_set @task is being moved to (may be NULL)
+ * @use_mg_tasks: move to @to_cset->mg_tasks instead of ->tasks
+ *
+ * Move @task from @from_cset to @to_cset.  If @task didn't belong to any
+ * css_set, @from_cset can be NULL.  If @task is being disassociated
+ * instead of moved, @to_cset can be NULL.
+ *
+ * This function automatically handles populated counter updates and
+ * css_task_iter adjustments but the caller is responsible for managing
+ * @from_cset and @to_cset's reference counts.
+ */
+static void css_set_move_task(struct task_struct *task,
+			      struct css_set *from_cset, struct css_set *to_cset,
+			      bool use_mg_tasks)
+{
+	lockdep_assert_held(&css_set_lock);
+
+	if (to_cset && !css_set_populated(to_cset))
+		css_set_update_populated(to_cset, true);
+
+	if (from_cset) {
+		WARN_ON_ONCE(list_empty(&task->cg_list));
+
+		css_set_skip_task_iters(from_cset, task);
+		list_del_init(&task->cg_list);
+		if (!css_set_populated(from_cset))
+			css_set_update_populated(from_cset, false);
+	} else {
+		WARN_ON_ONCE(!list_empty(&task->cg_list));
+	}
+
+	if (to_cset) {
+		/*
+		 * We are synchronized through cgroup_threadgroup_rwsem
+		 * against PF_EXITING setting such that we can't race
+		 * against cgroup_exit()/cgroup_free() dropping the css_set.
+		 */
+		WARN_ON_ONCE(task->flags & PF_EXITING);
+
+		cgroup_move_task(task, to_cset);
+		list_add_tail(&task->cg_list, use_mg_tasks ? &to_cset->mg_tasks :
+							     &to_cset->tasks);
+	}
+}
+
+/*
+ * hash table for cgroup groups. This improves the performance to find
+ * an existing css_set. This hash doesn't (currently) take into
+ * account cgroups in empty hierarchies.
+ */
+#define CSS_SET_HASH_BITS	7
+static DEFINE_HASHTABLE(css_set_table, CSS_SET_HASH_BITS);
+
+static unsigned long css_set_hash(struct cgroup_subsys_state *css[])
+{
+	unsigned long key = 0UL;
+	struct cgroup_subsys *ss;
+	int i;
+
+	for_each_subsys(ss, i)
+		key += (unsigned long)css[i];
+	key = (key >> 16) ^ key;
+
+	return key;
+}
+
+void put_css_set_locked(struct css_set *cset)
+{
+	struct cgrp_cset_link *link, *tmp_link;
+	struct cgroup_subsys *ss;
+	int ssid;
+
+	lockdep_assert_held(&css_set_lock);
+
+	if (!refcount_dec_and_test(&cset->refcount))
+		return;
+
+	WARN_ON_ONCE(!list_empty(&cset->threaded_csets));
+
+	/* This css_set is dead. Unlink it and release cgroup and css refs */
+	for_each_subsys(ss, ssid) {
+		list_del(&cset->e_cset_node[ssid]);
+		css_put(cset->subsys[ssid]);
+	}
+	hash_del(&cset->hlist);
+	css_set_count--;
+
+	list_for_each_entry_safe(link, tmp_link, &cset->cgrp_links, cgrp_link) {
+		list_del(&link->cset_link);
+		list_del(&link->cgrp_link);
+		if (cgroup_parent(link->cgrp))
+			cgroup_put(link->cgrp);
+		kfree(link);
+	}
+
+	if (css_set_threaded(cset)) {
+		list_del(&cset->threaded_csets_node);
+		put_css_set_locked(cset->dom_cset);
+	}
+
+	kfree_rcu(cset, rcu_head);
+}
+
+/**
+ * compare_css_sets - helper function for find_existing_css_set().
+ * @cset: candidate css_set being tested
+ * @old_cset: existing css_set for a task
+ * @new_cgrp: cgroup that's being entered by the task
+ * @template: desired set of css pointers in css_set (pre-calculated)
+ *
+ * Returns true if "cset" matches "old_cset" except for the hierarchy
+ * which "new_cgrp" belongs to, for which it should match "new_cgrp".
+ */
+static bool compare_css_sets(struct css_set *cset,
+			     struct css_set *old_cset,
+			     struct cgroup *new_cgrp,
+			     struct cgroup_subsys_state *template[])
+{
+	struct cgroup *new_dfl_cgrp;
+	struct list_head *l1, *l2;
+
+	/*
+	 * On the default hierarchy, there can be csets which are
+	 * associated with the same set of cgroups but different csses.
+	 * Let's first ensure that csses match.
+	 */
+	if (memcmp(template, cset->subsys, sizeof(cset->subsys)))
+		return false;
+
+
+	/* @cset's domain should match the default cgroup's */
+	if (cgroup_on_dfl(new_cgrp))
+		new_dfl_cgrp = new_cgrp;
+	else
+		new_dfl_cgrp = old_cset->dfl_cgrp;
+
+	if (new_dfl_cgrp->dom_cgrp != cset->dom_cset->dfl_cgrp)
+		return false;
+
+	/*
+	 * Compare cgroup pointers in order to distinguish between
+	 * different cgroups in hierarchies.  As different cgroups may
+	 * share the same effective css, this comparison is always
+	 * necessary.
+	 */
+	l1 = &cset->cgrp_links;
+	l2 = &old_cset->cgrp_links;
+	while (1) {
+		struct cgrp_cset_link *link1, *link2;
+		struct cgroup *cgrp1, *cgrp2;
+
+		l1 = l1->next;
+		l2 = l2->next;
+		/* See if we reached the end - both lists are equal length. */
+		if (l1 == &cset->cgrp_links) {
+			BUG_ON(l2 != &old_cset->cgrp_links);
+			break;
+		} else {
+			BUG_ON(l2 == &old_cset->cgrp_links);
+		}
+		/* Locate the cgroups associated with these links. */
+		link1 = list_entry(l1, struct cgrp_cset_link, cgrp_link);
+		link2 = list_entry(l2, struct cgrp_cset_link, cgrp_link);
+		cgrp1 = link1->cgrp;
+		cgrp2 = link2->cgrp;
+		/* Hierarchies should be linked in the same order. */
+		BUG_ON(cgrp1->root != cgrp2->root);
+
+		/*
+		 * If this hierarchy is the hierarchy of the cgroup
+		 * that's changing, then we need to check that this
+		 * css_set points to the new cgroup; if it's any other
+		 * hierarchy, then this css_set should point to the
+		 * same cgroup as the old css_set.
+		 */
+		if (cgrp1->root == new_cgrp->root) {
+			if (cgrp1 != new_cgrp)
+				return false;
+		} else {
+			if (cgrp1 != cgrp2)
+				return false;
+		}
+	}
+	return true;
+}
+
+/**
+ * find_existing_css_set - init css array and find the matching css_set
+ * @old_cset: the css_set that we're using before the cgroup transition
+ * @cgrp: the cgroup that we're moving into
+ * @template: out param for the new set of csses, should be clear on entry
+ */
+static struct css_set *find_existing_css_set(struct css_set *old_cset,
+					struct cgroup *cgrp,
+					struct cgroup_subsys_state *template[])
+{
+	struct cgroup_root *root = cgrp->root;
+	struct cgroup_subsys *ss;
+	struct css_set *cset;
+	unsigned long key;
+	int i;
+
+	/*
+	 * Build the set of subsystem state objects that we want to see in the
+	 * new css_set. While subsystems can change globally, the entries here
+	 * won't change, so no need for locking.
+	 */
+	for_each_subsys(ss, i) {
+		if (root->subsys_mask & (1UL << i)) {
+			/*
+			 * @ss is in this hierarchy, so we want the
+			 * effective css from @cgrp.
+			 */
+			template[i] = cgroup_e_css_by_mask(cgrp, ss);
+		} else {
+			/*
+			 * @ss is not in this hierarchy, so we don't want
+			 * to change the css.
+			 */
+			template[i] = old_cset->subsys[i];
+		}
+	}
+
+	key = css_set_hash(template);
+	hash_for_each_possible(css_set_table, cset, hlist, key) {
+		if (!compare_css_sets(cset, old_cset, cgrp, template))
+			continue;
+
+		/* This css_set matches what we need */
+		return cset;
+	}
+
+	/* No existing cgroup group matched */
+	return NULL;
+}
+
+static void free_cgrp_cset_links(struct list_head *links_to_free)
+{
+	struct cgrp_cset_link *link, *tmp_link;
+
+	list_for_each_entry_safe(link, tmp_link, links_to_free, cset_link) {
+		list_del(&link->cset_link);
+		kfree(link);
+	}
+}
+
+/**
+ * allocate_cgrp_cset_links - allocate cgrp_cset_links
+ * @count: the number of links to allocate
+ * @tmp_links: list_head the allocated links are put on
+ *
+ * Allocate @count cgrp_cset_link structures and chain them on @tmp_links
+ * through ->cset_link.  Returns 0 on success or -errno.
+ */
+static int allocate_cgrp_cset_links(int count, struct list_head *tmp_links)
+{
+	struct cgrp_cset_link *link;
+	int i;
+
+	INIT_LIST_HEAD(tmp_links);
+
+	for (i = 0; i < count; i++) {
+		link = kzalloc(sizeof(*link), GFP_KERNEL);
+		if (!link) {
+			free_cgrp_cset_links(tmp_links);
+			return -ENOMEM;
+		}
+		list_add(&link->cset_link, tmp_links);
+	}
+	return 0;
+}
+
+/**
+ * link_css_set - a helper function to link a css_set to a cgroup
+ * @tmp_links: cgrp_cset_link objects allocated by allocate_cgrp_cset_links()
+ * @cset: the css_set to be linked
+ * @cgrp: the destination cgroup
+ */
+static void link_css_set(struct list_head *tmp_links, struct css_set *cset,
+			 struct cgroup *cgrp)
+{
+	struct cgrp_cset_link *link;
+
+	BUG_ON(list_empty(tmp_links));
+
+	if (cgroup_on_dfl(cgrp))
+		cset->dfl_cgrp = cgrp;
+
+	link = list_first_entry(tmp_links, struct cgrp_cset_link, cset_link);
+	link->cset = cset;
+	link->cgrp = cgrp;
+
+	/*
+	 * Always add links to the tail of the lists so that the lists are
+	 * in chronological order.
+	 */
+	list_move_tail(&link->cset_link, &cgrp->cset_links);
+	list_add_tail(&link->cgrp_link, &cset->cgrp_links);
+
+	if (cgroup_parent(cgrp))
+		cgroup_get_live(cgrp);
+}
+
+/**
+ * find_css_set - return a new css_set with one cgroup updated
+ * @old_cset: the baseline css_set
+ * @cgrp: the cgroup to be updated
+ *
+ * Return a new css_set that's equivalent to @old_cset, but with @cgrp
+ * substituted into the appropriate hierarchy.
+ */
+static struct css_set *find_css_set(struct css_set *old_cset,
+				    struct cgroup *cgrp)
+{
+	struct cgroup_subsys_state *template[CGROUP_SUBSYS_COUNT] = { };
+	struct css_set *cset;
+	struct list_head tmp_links;
+	struct cgrp_cset_link *link;
+	struct cgroup_subsys *ss;
+	unsigned long key;
+	int ssid;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	/* First see if we already have a cgroup group that matches
+	 * the desired set */
+	spin_lock_irq(&css_set_lock);
+	cset = find_existing_css_set(old_cset, cgrp, template);
+	if (cset)
+		get_css_set(cset);
+	spin_unlock_irq(&css_set_lock);
+
+	if (cset)
+		return cset;
+
+	cset = kzalloc(sizeof(*cset), GFP_KERNEL);
+	if (!cset)
+		return NULL;
+
+	/* Allocate all the cgrp_cset_link objects that we'll need */
+	if (allocate_cgrp_cset_links(cgroup_root_count, &tmp_links) < 0) {
+		kfree(cset);
+		return NULL;
+	}
+
+	refcount_set(&cset->refcount, 1);
+	cset->dom_cset = cset;
+	INIT_LIST_HEAD(&cset->tasks);
+	INIT_LIST_HEAD(&cset->mg_tasks);
+	INIT_LIST_HEAD(&cset->dying_tasks);
+	INIT_LIST_HEAD(&cset->task_iters);
+	INIT_LIST_HEAD(&cset->threaded_csets);
+	INIT_HLIST_NODE(&cset->hlist);
+	INIT_LIST_HEAD(&cset->cgrp_links);
+	INIT_LIST_HEAD(&cset->mg_src_preload_node);
+	INIT_LIST_HEAD(&cset->mg_dst_preload_node);
+	INIT_LIST_HEAD(&cset->mg_node);
+
+	/* Copy the set of subsystem state objects generated in
+	 * find_existing_css_set() */
+	memcpy(cset->subsys, template, sizeof(cset->subsys));
+
+	spin_lock_irq(&css_set_lock);
+	/* Add reference counts and links from the new css_set. */
+	list_for_each_entry(link, &old_cset->cgrp_links, cgrp_link) {
+		struct cgroup *c = link->cgrp;
+
+		if (c->root == cgrp->root)
+			c = cgrp;
+		link_css_set(&tmp_links, cset, c);
+	}
+
+	BUG_ON(!list_empty(&tmp_links));
+
+	css_set_count++;
+
+	/* Add @cset to the hash table */
+	key = css_set_hash(cset->subsys);
+	hash_add(css_set_table, &cset->hlist, key);
+
+	for_each_subsys(ss, ssid) {
+		struct cgroup_subsys_state *css = cset->subsys[ssid];
+
+		list_add_tail(&cset->e_cset_node[ssid],
+			      &css->cgroup->e_csets[ssid]);
+		css_get(css);
+	}
+
+	spin_unlock_irq(&css_set_lock);
+
+	/*
+	 * If @cset should be threaded, look up the matching dom_cset and
+	 * link them up.  We first fully initialize @cset then look for the
+	 * dom_cset.  It's simpler this way and safe as @cset is guaranteed
+	 * to stay empty until we return.
+	 */
+	if (cgroup_is_threaded(cset->dfl_cgrp)) {
+		struct css_set *dcset;
+
+		dcset = find_css_set(cset, cset->dfl_cgrp->dom_cgrp);
+		if (!dcset) {
+			put_css_set(cset);
+			return NULL;
+		}
+
+		spin_lock_irq(&css_set_lock);
+		cset->dom_cset = dcset;
+		list_add_tail(&cset->threaded_csets_node,
+			      &dcset->threaded_csets);
+		spin_unlock_irq(&css_set_lock);
+	}
+
+	return cset;
+}
+
+struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root)
+{
+	struct cgroup *root_cgrp = kernfs_root_to_node(kf_root)->priv;
+
+	return root_cgrp->root;
+}
+
+void cgroup_favor_dynmods(struct cgroup_root *root, bool favor)
+{
+	bool favoring = root->flags & CGRP_ROOT_FAVOR_DYNMODS;
+
+	/* see the comment above CGRP_ROOT_FAVOR_DYNMODS definition */
+	if (favor && !favoring) {
+		rcu_sync_enter(&cgroup_threadgroup_rwsem.rss);
+		root->flags |= CGRP_ROOT_FAVOR_DYNMODS;
+	} else if (!favor && favoring) {
+		rcu_sync_exit(&cgroup_threadgroup_rwsem.rss);
+		root->flags &= ~CGRP_ROOT_FAVOR_DYNMODS;
+	}
+}
+
+static int cgroup_init_root_id(struct cgroup_root *root)
+{
+	int id;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	id = idr_alloc_cyclic(&cgroup_hierarchy_idr, root, 0, 0, GFP_KERNEL);
+	if (id < 0)
+		return id;
+
+	root->hierarchy_id = id;
+	return 0;
+}
+
+static void cgroup_exit_root_id(struct cgroup_root *root)
+{
+	lockdep_assert_held(&cgroup_mutex);
+
+	idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id);
+}
+
+void cgroup_free_root(struct cgroup_root *root)
+{
+	kfree(root);
+}
+
+static void cgroup_destroy_root(struct cgroup_root *root)
+{
+	struct cgroup *cgrp = &root->cgrp;
+	struct cgrp_cset_link *link, *tmp_link;
+
+	trace_cgroup_destroy_root(root);
+
+	cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
+
+	BUG_ON(atomic_read(&root->nr_cgrps));
+	BUG_ON(!list_empty(&cgrp->self.children));
+
+	/* Rebind all subsystems back to the default hierarchy */
+	WARN_ON(rebind_subsystems(&cgrp_dfl_root, root->subsys_mask));
+
+	/*
+	 * Release all the links from cset_links to this hierarchy's
+	 * root cgroup
+	 */
+	spin_lock_irq(&css_set_lock);
+
+	list_for_each_entry_safe(link, tmp_link, &cgrp->cset_links, cset_link) {
+		list_del(&link->cset_link);
+		list_del(&link->cgrp_link);
+		kfree(link);
+	}
+
+	spin_unlock_irq(&css_set_lock);
+
+	if (!list_empty(&root->root_list)) {
+		list_del(&root->root_list);
+		cgroup_root_count--;
+	}
+
+	cgroup_favor_dynmods(root, false);
+	cgroup_exit_root_id(root);
+
+	cgroup_unlock();
+
+	cgroup_rstat_exit(cgrp);
+	kernfs_destroy_root(root->kf_root);
+	cgroup_free_root(root);
+}
+
+/*
+ * Returned cgroup is without refcount but it's valid as long as cset pins it.
+ */
+static inline struct cgroup *__cset_cgroup_from_root(struct css_set *cset,
+					    struct cgroup_root *root)
+{
+	struct cgroup *res_cgroup = NULL;
+
+	if (cset == &init_css_set) {
+		res_cgroup = &root->cgrp;
+	} else if (root == &cgrp_dfl_root) {
+		res_cgroup = cset->dfl_cgrp;
+	} else {
+		struct cgrp_cset_link *link;
+		lockdep_assert_held(&css_set_lock);
+
+		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
+			struct cgroup *c = link->cgrp;
+
+			if (c->root == root) {
+				res_cgroup = c;
+				break;
+			}
+		}
+	}
+
+	BUG_ON(!res_cgroup);
+	return res_cgroup;
+}
+
+/*
+ * look up cgroup associated with current task's cgroup namespace on the
+ * specified hierarchy
+ */
+static struct cgroup *
+current_cgns_cgroup_from_root(struct cgroup_root *root)
+{
+	struct cgroup *res = NULL;
+	struct css_set *cset;
+
+	lockdep_assert_held(&css_set_lock);
+
+	rcu_read_lock();
+
+	cset = current->nsproxy->cgroup_ns->root_cset;
+	res = __cset_cgroup_from_root(cset, root);
+
+	rcu_read_unlock();
+
+	return res;
+}
+
+/*
+ * Look up cgroup associated with current task's cgroup namespace on the default
+ * hierarchy.
+ *
+ * Unlike current_cgns_cgroup_from_root(), this doesn't need locks:
+ * - Internal rcu_read_lock is unnecessary because we don't dereference any rcu
+ *   pointers.
+ * - css_set_lock is not needed because we just read cset->dfl_cgrp.
+ * - As a bonus returned cgrp is pinned with the current because it cannot
+ *   switch cgroup_ns asynchronously.
+ */
+static struct cgroup *current_cgns_cgroup_dfl(void)
+{
+	struct css_set *cset;
+
+	cset = current->nsproxy->cgroup_ns->root_cset;
+	return __cset_cgroup_from_root(cset, &cgrp_dfl_root);
+}
+
+/* look up cgroup associated with given css_set on the specified hierarchy */
+static struct cgroup *cset_cgroup_from_root(struct css_set *cset,
+					    struct cgroup_root *root)
+{
+	lockdep_assert_held(&cgroup_mutex);
+	lockdep_assert_held(&css_set_lock);
+
+	return __cset_cgroup_from_root(cset, root);
+}
+
+/*
+ * Return the cgroup for "task" from the given hierarchy. Must be
+ * called with cgroup_mutex and css_set_lock held.
+ */
+struct cgroup *task_cgroup_from_root(struct task_struct *task,
+				     struct cgroup_root *root)
+{
+	/*
+	 * No need to lock the task - since we hold css_set_lock the
+	 * task can't change groups.
+	 */
+	return cset_cgroup_from_root(task_css_set(task), root);
+}
+
+/*
+ * A task must hold cgroup_mutex to modify cgroups.
+ *
+ * Any task can increment and decrement the count field without lock.
+ * So in general, code holding cgroup_mutex can't rely on the count
+ * field not changing.  However, if the count goes to zero, then only
+ * cgroup_attach_task() can increment it again.  Because a count of zero
+ * means that no tasks are currently attached, therefore there is no
+ * way a task attached to that cgroup can fork (the other way to
+ * increment the count).  So code holding cgroup_mutex can safely
+ * assume that if the count is zero, it will stay zero. Similarly, if
+ * a task holds cgroup_mutex on a cgroup with zero count, it
+ * knows that the cgroup won't be removed, as cgroup_rmdir()
+ * needs that mutex.
+ *
+ * A cgroup can only be deleted if both its 'count' of using tasks
+ * is zero, and its list of 'children' cgroups is empty.  Since all
+ * tasks in the system use _some_ cgroup, and since there is always at
+ * least one task in the system (init, pid == 1), therefore, root cgroup
+ * always has either children cgroups and/or using tasks.  So we don't
+ * need a special hack to ensure that root cgroup cannot be deleted.
+ *
+ * P.S.  One more locking exception.  RCU is used to guard the
+ * update of a tasks cgroup pointer by cgroup_attach_task()
+ */
+
+static struct kernfs_syscall_ops cgroup_kf_syscall_ops;
+
+static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,
+			      char *buf)
+{
+	struct cgroup_subsys *ss = cft->ss;
+
+	if (cft->ss && !(cft->flags & CFTYPE_NO_PREFIX) &&
+	    !(cgrp->root->flags & CGRP_ROOT_NOPREFIX)) {
+		const char *dbg = (cft->flags & CFTYPE_DEBUG) ? ".__DEBUG__." : "";
+
+		snprintf(buf, CGROUP_FILE_NAME_MAX, "%s%s.%s",
+			 dbg, cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
+			 cft->name);
+	} else {
+		strscpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
+	}
+	return buf;
+}
+
+/**
+ * cgroup_file_mode - deduce file mode of a control file
+ * @cft: the control file in question
+ *
+ * S_IRUGO for read, S_IWUSR for write.
+ */
+static umode_t cgroup_file_mode(const struct cftype *cft)
+{
+	umode_t mode = 0;
+
+	if (cft->read_u64 || cft->read_s64 || cft->seq_show)
+		mode |= S_IRUGO;
+
+	if (cft->write_u64 || cft->write_s64 || cft->write) {
+		if (cft->flags & CFTYPE_WORLD_WRITABLE)
+			mode |= S_IWUGO;
+		else
+			mode |= S_IWUSR;
+	}
+
+	return mode;
+}
+
+/**
+ * cgroup_calc_subtree_ss_mask - calculate subtree_ss_mask
+ * @subtree_control: the new subtree_control mask to consider
+ * @this_ss_mask: available subsystems
+ *
+ * On the default hierarchy, a subsystem may request other subsystems to be
+ * enabled together through its ->depends_on mask.  In such cases, more
+ * subsystems than specified in "cgroup.subtree_control" may be enabled.
+ *
+ * This function calculates which subsystems need to be enabled if
+ * @subtree_control is to be applied while restricted to @this_ss_mask.
+ */
+static u16 cgroup_calc_subtree_ss_mask(u16 subtree_control, u16 this_ss_mask)
+{
+	u16 cur_ss_mask = subtree_control;
+	struct cgroup_subsys *ss;
+	int ssid;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	cur_ss_mask |= cgrp_dfl_implicit_ss_mask;
+
+	while (true) {
+		u16 new_ss_mask = cur_ss_mask;
+
+		do_each_subsys_mask(ss, ssid, cur_ss_mask) {
+			new_ss_mask |= ss->depends_on;
+		} while_each_subsys_mask();
+
+		/*
+		 * Mask out subsystems which aren't available.  This can
+		 * happen only if some depended-upon subsystems were bound
+		 * to non-default hierarchies.
+		 */
+		new_ss_mask &= this_ss_mask;
+
+		if (new_ss_mask == cur_ss_mask)
+			break;
+		cur_ss_mask = new_ss_mask;
+	}
+
+	return cur_ss_mask;
+}
+
+/**
+ * cgroup_kn_unlock - unlocking helper for cgroup kernfs methods
+ * @kn: the kernfs_node being serviced
+ *
+ * This helper undoes cgroup_kn_lock_live() and should be invoked before
+ * the method finishes if locking succeeded.  Note that once this function
+ * returns the cgroup returned by cgroup_kn_lock_live() may become
+ * inaccessible any time.  If the caller intends to continue to access the
+ * cgroup, it should pin it before invoking this function.
+ */
+void cgroup_kn_unlock(struct kernfs_node *kn)
+{
+	struct cgroup *cgrp;
+
+	if (kernfs_type(kn) == KERNFS_DIR)
+		cgrp = kn->priv;
+	else
+		cgrp = kn->parent->priv;
+
+	cgroup_unlock();
+
+	kernfs_unbreak_active_protection(kn);
+	cgroup_put(cgrp);
+}
+
+/**
+ * cgroup_kn_lock_live - locking helper for cgroup kernfs methods
+ * @kn: the kernfs_node being serviced
+ * @drain_offline: perform offline draining on the cgroup
+ *
+ * This helper is to be used by a cgroup kernfs method currently servicing
+ * @kn.  It breaks the active protection, performs cgroup locking and
+ * verifies that the associated cgroup is alive.  Returns the cgroup if
+ * alive; otherwise, %NULL.  A successful return should be undone by a
+ * matching cgroup_kn_unlock() invocation.  If @drain_offline is %true, the
+ * cgroup is drained of offlining csses before return.
+ *
+ * Any cgroup kernfs method implementation which requires locking the
+ * associated cgroup should use this helper.  It avoids nesting cgroup
+ * locking under kernfs active protection and allows all kernfs operations
+ * including self-removal.
+ */
+struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline)
+{
+	struct cgroup *cgrp;
+
+	if (kernfs_type(kn) == KERNFS_DIR)
+		cgrp = kn->priv;
+	else
+		cgrp = kn->parent->priv;
+
+	/*
+	 * We're gonna grab cgroup_mutex which nests outside kernfs
+	 * active_ref.  cgroup liveliness check alone provides enough
+	 * protection against removal.  Ensure @cgrp stays accessible and
+	 * break the active_ref protection.
+	 */
+	if (!cgroup_tryget(cgrp))
+		return NULL;
+	kernfs_break_active_protection(kn);
+
+	if (drain_offline)
+		cgroup_lock_and_drain_offline(cgrp);
+	else
+		cgroup_lock();
+
+	if (!cgroup_is_dead(cgrp))
+		return cgrp;
+
+	cgroup_kn_unlock(kn);
+	return NULL;
+}
+
+static void cgroup_rm_file(struct cgroup *cgrp, const struct cftype *cft)
+{
+	char name[CGROUP_FILE_NAME_MAX];
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	if (cft->file_offset) {
+		struct cgroup_subsys_state *css = cgroup_css(cgrp, cft->ss);
+		struct cgroup_file *cfile = (void *)css + cft->file_offset;
+
+		spin_lock_irq(&cgroup_file_kn_lock);
+		cfile->kn = NULL;
+		spin_unlock_irq(&cgroup_file_kn_lock);
+
+		del_timer_sync(&cfile->notify_timer);
+	}
+
+	kernfs_remove_by_name(cgrp->kn, cgroup_file_name(cgrp, cft, name));
+}
+
+/**
+ * css_clear_dir - remove subsys files in a cgroup directory
+ * @css: target css
+ */
+static void css_clear_dir(struct cgroup_subsys_state *css)
+{
+	struct cgroup *cgrp = css->cgroup;
+	struct cftype *cfts;
+
+	if (!(css->flags & CSS_VISIBLE))
+		return;
+
+	css->flags &= ~CSS_VISIBLE;
+
+	if (!css->ss) {
+		if (cgroup_on_dfl(cgrp)) {
+			cgroup_addrm_files(css, cgrp,
+					   cgroup_base_files, false);
+			if (cgroup_psi_enabled())
+				cgroup_addrm_files(css, cgrp,
+						   cgroup_psi_files, false);
+		} else {
+			cgroup_addrm_files(css, cgrp,
+					   cgroup1_base_files, false);
+		}
+	} else {
+		list_for_each_entry(cfts, &css->ss->cfts, node)
+			cgroup_addrm_files(css, cgrp, cfts, false);
+	}
+}
+
+/**
+ * css_populate_dir - create subsys files in a cgroup directory
+ * @css: target css
+ *
+ * On failure, no file is added.
+ */
+static int css_populate_dir(struct cgroup_subsys_state *css)
+{
+	struct cgroup *cgrp = css->cgroup;
+	struct cftype *cfts, *failed_cfts;
+	int ret;
+
+	if ((css->flags & CSS_VISIBLE) || !cgrp->kn)
+		return 0;
+
+	if (!css->ss) {
+		if (cgroup_on_dfl(cgrp)) {
+			ret = cgroup_addrm_files(&cgrp->self, cgrp,
+						 cgroup_base_files, true);
+			if (ret < 0)
+				return ret;
+
+			if (cgroup_psi_enabled()) {
+				ret = cgroup_addrm_files(&cgrp->self, cgrp,
+							 cgroup_psi_files, true);
+				if (ret < 0)
+					return ret;
+			}
+		} else {
+			cgroup_addrm_files(css, cgrp,
+					   cgroup1_base_files, true);
+		}
+	} else {
+		list_for_each_entry(cfts, &css->ss->cfts, node) {
+			ret = cgroup_addrm_files(css, cgrp, cfts, true);
+			if (ret < 0) {
+				failed_cfts = cfts;
+				goto err;
+			}
+		}
+	}
+
+	css->flags |= CSS_VISIBLE;
+
+	return 0;
+err:
+	list_for_each_entry(cfts, &css->ss->cfts, node) {
+		if (cfts == failed_cfts)
+			break;
+		cgroup_addrm_files(css, cgrp, cfts, false);
+	}
+	return ret;
+}
+
+int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask)
+{
+	struct cgroup *dcgrp = &dst_root->cgrp;
+	struct cgroup_subsys *ss;
+	int ssid, ret;
+	u16 dfl_disable_ss_mask = 0;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	do_each_subsys_mask(ss, ssid, ss_mask) {
+		/*
+		 * If @ss has non-root csses attached to it, can't move.
+		 * If @ss is an implicit controller, it is exempt from this
+		 * rule and can be stolen.
+		 */
+		if (css_next_child(NULL, cgroup_css(&ss->root->cgrp, ss)) &&
+		    !ss->implicit_on_dfl)
+			return -EBUSY;
+
+		/* can't move between two non-dummy roots either */
+		if (ss->root != &cgrp_dfl_root && dst_root != &cgrp_dfl_root)
+			return -EBUSY;
+
+		/*
+		 * Collect ssid's that need to be disabled from default
+		 * hierarchy.
+		 */
+		if (ss->root == &cgrp_dfl_root)
+			dfl_disable_ss_mask |= 1 << ssid;
+
+	} while_each_subsys_mask();
+
+	if (dfl_disable_ss_mask) {
+		struct cgroup *scgrp = &cgrp_dfl_root.cgrp;
+
+		/*
+		 * Controllers from default hierarchy that need to be rebound
+		 * are all disabled together in one go.
+		 */
+		cgrp_dfl_root.subsys_mask &= ~dfl_disable_ss_mask;
+		WARN_ON(cgroup_apply_control(scgrp));
+		cgroup_finalize_control(scgrp, 0);
+	}
+
+	do_each_subsys_mask(ss, ssid, ss_mask) {
+		struct cgroup_root *src_root = ss->root;
+		struct cgroup *scgrp = &src_root->cgrp;
+		struct cgroup_subsys_state *css = cgroup_css(scgrp, ss);
+		struct css_set *cset, *cset_pos;
+		struct css_task_iter *it;
+
+		WARN_ON(!css || cgroup_css(dcgrp, ss));
+
+		if (src_root != &cgrp_dfl_root) {
+			/* disable from the source */
+			src_root->subsys_mask &= ~(1 << ssid);
+			WARN_ON(cgroup_apply_control(scgrp));
+			cgroup_finalize_control(scgrp, 0);
+		}
+
+		/* rebind */
+		RCU_INIT_POINTER(scgrp->subsys[ssid], NULL);
+		rcu_assign_pointer(dcgrp->subsys[ssid], css);
+		ss->root = dst_root;
+		css->cgroup = dcgrp;
+
+		spin_lock_irq(&css_set_lock);
+		WARN_ON(!list_empty(&dcgrp->e_csets[ss->id]));
+		list_for_each_entry_safe(cset, cset_pos, &scgrp->e_csets[ss->id],
+					 e_cset_node[ss->id]) {
+			list_move_tail(&cset->e_cset_node[ss->id],
+				       &dcgrp->e_csets[ss->id]);
+			/*
+			 * all css_sets of scgrp together in same order to dcgrp,
+			 * patch in-flight iterators to preserve correct iteration.
+			 * since the iterator is always advanced right away and
+			 * finished when it->cset_pos meets it->cset_head, so only
+			 * update it->cset_head is enough here.
+			 */
+			list_for_each_entry(it, &cset->task_iters, iters_node)
+				if (it->cset_head == &scgrp->e_csets[ss->id])
+					it->cset_head = &dcgrp->e_csets[ss->id];
+		}
+		spin_unlock_irq(&css_set_lock);
+
+		if (ss->css_rstat_flush) {
+			list_del_rcu(&css->rstat_css_node);
+			synchronize_rcu();
+			list_add_rcu(&css->rstat_css_node,
+				     &dcgrp->rstat_css_list);
+		}
+
+		/* default hierarchy doesn't enable controllers by default */
+		dst_root->subsys_mask |= 1 << ssid;
+		if (dst_root == &cgrp_dfl_root) {
+			static_branch_enable(cgroup_subsys_on_dfl_key[ssid]);
+		} else {
+			dcgrp->subtree_control |= 1 << ssid;
+			static_branch_disable(cgroup_subsys_on_dfl_key[ssid]);
+		}
+
+		ret = cgroup_apply_control(dcgrp);
+		if (ret)
+			pr_warn("partial failure to rebind %s controller (err=%d)\n",
+				ss->name, ret);
+
+		if (ss->bind)
+			ss->bind(css);
+	} while_each_subsys_mask();
+
+	kernfs_activate(dcgrp->kn);
+	return 0;
+}
+
+int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
+		     struct kernfs_root *kf_root)
+{
+	int len = 0;
+	char *buf = NULL;
+	struct cgroup_root *kf_cgroot = cgroup_root_from_kf(kf_root);
+	struct cgroup *ns_cgroup;
+
+	buf = kmalloc(PATH_MAX, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	spin_lock_irq(&css_set_lock);
+	ns_cgroup = current_cgns_cgroup_from_root(kf_cgroot);
+	len = kernfs_path_from_node(kf_node, ns_cgroup->kn, buf, PATH_MAX);
+	spin_unlock_irq(&css_set_lock);
+
+	if (len >= PATH_MAX)
+		len = -ERANGE;
+	else if (len > 0) {
+		seq_escape(sf, buf, " \t\n\\");
+		len = 0;
+	}
+	kfree(buf);
+	return len;
+}
+
+enum cgroup2_param {
+	Opt_nsdelegate,
+	Opt_favordynmods,
+	Opt_memory_localevents,
+	Opt_memory_recursiveprot,
+	nr__cgroup2_params
+};
+
+static const struct fs_parameter_spec cgroup2_fs_parameters[] = {
+	fsparam_flag("nsdelegate",		Opt_nsdelegate),
+	fsparam_flag("favordynmods",		Opt_favordynmods),
+	fsparam_flag("memory_localevents",	Opt_memory_localevents),
+	fsparam_flag("memory_recursiveprot",	Opt_memory_recursiveprot),
+	{}
+};
+
+static int cgroup2_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+	struct fs_parse_result result;
+	int opt;
+
+	opt = fs_parse(fc, cgroup2_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_nsdelegate:
+		ctx->flags |= CGRP_ROOT_NS_DELEGATE;
+		return 0;
+	case Opt_favordynmods:
+		ctx->flags |= CGRP_ROOT_FAVOR_DYNMODS;
+		return 0;
+	case Opt_memory_localevents:
+		ctx->flags |= CGRP_ROOT_MEMORY_LOCAL_EVENTS;
+		return 0;
+	case Opt_memory_recursiveprot:
+		ctx->flags |= CGRP_ROOT_MEMORY_RECURSIVE_PROT;
+		return 0;
+	}
+	return -EINVAL;
+}
+
+static void apply_cgroup_root_flags(unsigned int root_flags)
+{
+	if (current->nsproxy->cgroup_ns == &init_cgroup_ns) {
+		if (root_flags & CGRP_ROOT_NS_DELEGATE)
+			cgrp_dfl_root.flags |= CGRP_ROOT_NS_DELEGATE;
+		else
+			cgrp_dfl_root.flags &= ~CGRP_ROOT_NS_DELEGATE;
+
+		cgroup_favor_dynmods(&cgrp_dfl_root,
+				     root_flags & CGRP_ROOT_FAVOR_DYNMODS);
+
+		if (root_flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS)
+			cgrp_dfl_root.flags |= CGRP_ROOT_MEMORY_LOCAL_EVENTS;
+		else
+			cgrp_dfl_root.flags &= ~CGRP_ROOT_MEMORY_LOCAL_EVENTS;
+
+		if (root_flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT)
+			cgrp_dfl_root.flags |= CGRP_ROOT_MEMORY_RECURSIVE_PROT;
+		else
+			cgrp_dfl_root.flags &= ~CGRP_ROOT_MEMORY_RECURSIVE_PROT;
+	}
+}
+
+static int cgroup_show_options(struct seq_file *seq, struct kernfs_root *kf_root)
+{
+	if (cgrp_dfl_root.flags & CGRP_ROOT_NS_DELEGATE)
+		seq_puts(seq, ",nsdelegate");
+	if (cgrp_dfl_root.flags & CGRP_ROOT_FAVOR_DYNMODS)
+		seq_puts(seq, ",favordynmods");
+	if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS)
+		seq_puts(seq, ",memory_localevents");
+	if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT)
+		seq_puts(seq, ",memory_recursiveprot");
+	return 0;
+}
+
+static int cgroup_reconfigure(struct fs_context *fc)
+{
+	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+
+	apply_cgroup_root_flags(ctx->flags);
+	return 0;
+}
+
+static void init_cgroup_housekeeping(struct cgroup *cgrp)
+{
+	struct cgroup_subsys *ss;
+	int ssid;
+
+	INIT_LIST_HEAD(&cgrp->self.sibling);
+	INIT_LIST_HEAD(&cgrp->self.children);
+	INIT_LIST_HEAD(&cgrp->cset_links);
+	INIT_LIST_HEAD(&cgrp->pidlists);
+	mutex_init(&cgrp->pidlist_mutex);
+	cgrp->self.cgroup = cgrp;
+	cgrp->self.flags |= CSS_ONLINE;
+	cgrp->dom_cgrp = cgrp;
+	cgrp->max_descendants = INT_MAX;
+	cgrp->max_depth = INT_MAX;
+	INIT_LIST_HEAD(&cgrp->rstat_css_list);
+	prev_cputime_init(&cgrp->prev_cputime);
+
+	for_each_subsys(ss, ssid)
+		INIT_LIST_HEAD(&cgrp->e_csets[ssid]);
+
+	init_waitqueue_head(&cgrp->offline_waitq);
+	INIT_WORK(&cgrp->release_agent_work, cgroup1_release_agent);
+}
+
+void init_cgroup_root(struct cgroup_fs_context *ctx)
+{
+	struct cgroup_root *root = ctx->root;
+	struct cgroup *cgrp = &root->cgrp;
+
+	INIT_LIST_HEAD(&root->root_list);
+	atomic_set(&root->nr_cgrps, 1);
+	cgrp->root = root;
+	init_cgroup_housekeeping(cgrp);
+
+	/* DYNMODS must be modified through cgroup_favor_dynmods() */
+	root->flags = ctx->flags & ~CGRP_ROOT_FAVOR_DYNMODS;
+	if (ctx->release_agent)
+		strscpy(root->release_agent_path, ctx->release_agent, PATH_MAX);
+	if (ctx->name)
+		strscpy(root->name, ctx->name, MAX_CGROUP_ROOT_NAMELEN);
+	if (ctx->cpuset_clone_children)
+		set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags);
+}
+
+int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
+{
+	LIST_HEAD(tmp_links);
+	struct cgroup *root_cgrp = &root->cgrp;
+	struct kernfs_syscall_ops *kf_sops;
+	struct css_set *cset;
+	int i, ret;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	ret = percpu_ref_init(&root_cgrp->self.refcnt, css_release,
+			      0, GFP_KERNEL);
+	if (ret)
+		goto out;
+
+	/*
+	 * We're accessing css_set_count without locking css_set_lock here,
+	 * but that's OK - it can only be increased by someone holding
+	 * cgroup_lock, and that's us.  Later rebinding may disable
+	 * controllers on the default hierarchy and thus create new csets,
+	 * which can't be more than the existing ones.  Allocate 2x.
+	 */
+	ret = allocate_cgrp_cset_links(2 * css_set_count, &tmp_links);
+	if (ret)
+		goto cancel_ref;
+
+	ret = cgroup_init_root_id(root);
+	if (ret)
+		goto cancel_ref;
+
+	kf_sops = root == &cgrp_dfl_root ?
+		&cgroup_kf_syscall_ops : &cgroup1_kf_syscall_ops;
+
+	root->kf_root = kernfs_create_root(kf_sops,
+					   KERNFS_ROOT_CREATE_DEACTIVATED |
+					   KERNFS_ROOT_SUPPORT_EXPORTOP |
+					   KERNFS_ROOT_SUPPORT_USER_XATTR,
+					   root_cgrp);
+	if (IS_ERR(root->kf_root)) {
+		ret = PTR_ERR(root->kf_root);
+		goto exit_root_id;
+	}
+	root_cgrp->kn = kernfs_root_to_node(root->kf_root);
+	WARN_ON_ONCE(cgroup_ino(root_cgrp) != 1);
+	root_cgrp->ancestors[0] = root_cgrp;
+
+	ret = css_populate_dir(&root_cgrp->self);
+	if (ret)
+		goto destroy_root;
+
+	ret = cgroup_rstat_init(root_cgrp);
+	if (ret)
+		goto destroy_root;
+
+	ret = rebind_subsystems(root, ss_mask);
+	if (ret)
+		goto exit_stats;
+
+	ret = cgroup_bpf_inherit(root_cgrp);
+	WARN_ON_ONCE(ret);
+
+	trace_cgroup_setup_root(root);
+
+	/*
+	 * There must be no failure case after here, since rebinding takes
+	 * care of subsystems' refcounts, which are explicitly dropped in
+	 * the failure exit path.
+	 */
+	list_add(&root->root_list, &cgroup_roots);
+	cgroup_root_count++;
+
+	/*
+	 * Link the root cgroup in this hierarchy into all the css_set
+	 * objects.
+	 */
+	spin_lock_irq(&css_set_lock);
+	hash_for_each(css_set_table, i, cset, hlist) {
+		link_css_set(&tmp_links, cset, root_cgrp);
+		if (css_set_populated(cset))
+			cgroup_update_populated(root_cgrp, true);
+	}
+	spin_unlock_irq(&css_set_lock);
+
+	BUG_ON(!list_empty(&root_cgrp->self.children));
+	BUG_ON(atomic_read(&root->nr_cgrps) != 1);
+
+	ret = 0;
+	goto out;
+
+exit_stats:
+	cgroup_rstat_exit(root_cgrp);
+destroy_root:
+	kernfs_destroy_root(root->kf_root);
+	root->kf_root = NULL;
+exit_root_id:
+	cgroup_exit_root_id(root);
+cancel_ref:
+	percpu_ref_exit(&root_cgrp->self.refcnt);
+out:
+	free_cgrp_cset_links(&tmp_links);
+	return ret;
+}
+
+int cgroup_do_get_tree(struct fs_context *fc)
+{
+	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+	int ret;
+
+	ctx->kfc.root = ctx->root->kf_root;
+	if (fc->fs_type == &cgroup2_fs_type)
+		ctx->kfc.magic = CGROUP2_SUPER_MAGIC;
+	else
+		ctx->kfc.magic = CGROUP_SUPER_MAGIC;
+	ret = kernfs_get_tree(fc);
+
+	/*
+	 * In non-init cgroup namespace, instead of root cgroup's dentry,
+	 * we return the dentry corresponding to the cgroupns->root_cgrp.
+	 */
+	if (!ret && ctx->ns != &init_cgroup_ns) {
+		struct dentry *nsdentry;
+		struct super_block *sb = fc->root->d_sb;
+		struct cgroup *cgrp;
+
+		cgroup_lock();
+		spin_lock_irq(&css_set_lock);
+
+		cgrp = cset_cgroup_from_root(ctx->ns->root_cset, ctx->root);
+
+		spin_unlock_irq(&css_set_lock);
+		cgroup_unlock();
+
+		nsdentry = kernfs_node_dentry(cgrp->kn, sb);
+		dput(fc->root);
+		if (IS_ERR(nsdentry)) {
+			deactivate_locked_super(sb);
+			ret = PTR_ERR(nsdentry);
+			nsdentry = NULL;
+		}
+		fc->root = nsdentry;
+	}
+
+	if (!ctx->kfc.new_sb_created)
+		cgroup_put(&ctx->root->cgrp);
+
+	return ret;
+}
+
+/*
+ * Destroy a cgroup filesystem context.
+ */
+static void cgroup_fs_context_free(struct fs_context *fc)
+{
+	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+
+	kfree(ctx->name);
+	kfree(ctx->release_agent);
+	put_cgroup_ns(ctx->ns);
+	kernfs_free_fs_context(fc);
+	kfree(ctx);
+}
+
+static int cgroup_get_tree(struct fs_context *fc)
+{
+	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+	int ret;
+
+	WRITE_ONCE(cgrp_dfl_visible, true);
+	cgroup_get_live(&cgrp_dfl_root.cgrp);
+	ctx->root = &cgrp_dfl_root;
+
+	ret = cgroup_do_get_tree(fc);
+	if (!ret)
+		apply_cgroup_root_flags(ctx->flags);
+	return ret;
+}
+
+static const struct fs_context_operations cgroup_fs_context_ops = {
+	.free		= cgroup_fs_context_free,
+	.parse_param	= cgroup2_parse_param,
+	.get_tree	= cgroup_get_tree,
+	.reconfigure	= cgroup_reconfigure,
+};
+
+static const struct fs_context_operations cgroup1_fs_context_ops = {
+	.free		= cgroup_fs_context_free,
+	.parse_param	= cgroup1_parse_param,
+	.get_tree	= cgroup1_get_tree,
+	.reconfigure	= cgroup1_reconfigure,
+};
+
+/*
+ * Initialise the cgroup filesystem creation/reconfiguration context.  Notably,
+ * we select the namespace we're going to use.
+ */
+static int cgroup_init_fs_context(struct fs_context *fc)
+{
+	struct cgroup_fs_context *ctx;
+
+	ctx = kzalloc(sizeof(struct cgroup_fs_context), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->ns = current->nsproxy->cgroup_ns;
+	get_cgroup_ns(ctx->ns);
+	fc->fs_private = &ctx->kfc;
+	if (fc->fs_type == &cgroup2_fs_type)
+		fc->ops = &cgroup_fs_context_ops;
+	else
+		fc->ops = &cgroup1_fs_context_ops;
+	put_user_ns(fc->user_ns);
+	fc->user_ns = get_user_ns(ctx->ns->user_ns);
+	fc->global = true;
+
+#ifdef CONFIG_CGROUP_FAVOR_DYNMODS
+	ctx->flags |= CGRP_ROOT_FAVOR_DYNMODS;
+#endif
+	return 0;
+}
+
+static void cgroup_kill_sb(struct super_block *sb)
+{
+	struct kernfs_root *kf_root = kernfs_root_from_sb(sb);
+	struct cgroup_root *root = cgroup_root_from_kf(kf_root);
+
+	/*
+	 * If @root doesn't have any children, start killing it.
+	 * This prevents new mounts by disabling percpu_ref_tryget_live().
+	 *
+	 * And don't kill the default root.
+	 */
+	if (list_empty(&root->cgrp.self.children) && root != &cgrp_dfl_root &&
+	    !percpu_ref_is_dying(&root->cgrp.self.refcnt)) {
+		cgroup_bpf_offline(&root->cgrp);
+		percpu_ref_kill(&root->cgrp.self.refcnt);
+	}
+	cgroup_put(&root->cgrp);
+	kernfs_kill_sb(sb);
+}
+
+struct file_system_type cgroup_fs_type = {
+	.name			= "cgroup",
+	.init_fs_context	= cgroup_init_fs_context,
+	.parameters		= cgroup1_fs_parameters,
+	.kill_sb		= cgroup_kill_sb,
+	.fs_flags		= FS_USERNS_MOUNT,
+};
+
+static struct file_system_type cgroup2_fs_type = {
+	.name			= "cgroup2",
+	.init_fs_context	= cgroup_init_fs_context,
+	.parameters		= cgroup2_fs_parameters,
+	.kill_sb		= cgroup_kill_sb,
+	.fs_flags		= FS_USERNS_MOUNT,
+};
+
+#ifdef CONFIG_CPUSETS
+static const struct fs_context_operations cpuset_fs_context_ops = {
+	.get_tree	= cgroup1_get_tree,
+	.free		= cgroup_fs_context_free,
+};
+
+/*
+ * This is ugly, but preserves the userspace API for existing cpuset
+ * users. If someone tries to mount the "cpuset" filesystem, we
+ * silently switch it to mount "cgroup" instead
+ */
+static int cpuset_init_fs_context(struct fs_context *fc)
+{
+	char *agent = kstrdup("/sbin/cpuset_release_agent", GFP_USER);
+	struct cgroup_fs_context *ctx;
+	int err;
+
+	err = cgroup_init_fs_context(fc);
+	if (err) {
+		kfree(agent);
+		return err;
+	}
+
+	fc->ops = &cpuset_fs_context_ops;
+
+	ctx = cgroup_fc2context(fc);
+	ctx->subsys_mask = 1 << cpuset_cgrp_id;
+	ctx->flags |= CGRP_ROOT_NOPREFIX;
+	ctx->release_agent = agent;
+
+	get_filesystem(&cgroup_fs_type);
+	put_filesystem(fc->fs_type);
+	fc->fs_type = &cgroup_fs_type;
+
+	return 0;
+}
+
+static struct file_system_type cpuset_fs_type = {
+	.name			= "cpuset",
+	.init_fs_context	= cpuset_init_fs_context,
+	.fs_flags		= FS_USERNS_MOUNT,
+};
+#endif
+
+int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
+			  struct cgroup_namespace *ns)
+{
+	struct cgroup *root = cset_cgroup_from_root(ns->root_cset, cgrp->root);
+
+	return kernfs_path_from_node(cgrp->kn, root->kn, buf, buflen);
+}
+
+int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+		   struct cgroup_namespace *ns)
+{
+	int ret;
+
+	cgroup_lock();
+	spin_lock_irq(&css_set_lock);
+
+	ret = cgroup_path_ns_locked(cgrp, buf, buflen, ns);
+
+	spin_unlock_irq(&css_set_lock);
+	cgroup_unlock();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cgroup_path_ns);
+
+/**
+ * task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
+ * @task: target task
+ * @buf: the buffer to write the path into
+ * @buflen: the length of the buffer
+ *
+ * Determine @task's cgroup on the first (the one with the lowest non-zero
+ * hierarchy_id) cgroup hierarchy and copy its path into @buf.  This
+ * function grabs cgroup_mutex and shouldn't be used inside locks used by
+ * cgroup controller callbacks.
+ *
+ * Return value is the same as kernfs_path().
+ */
+int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
+{
+	struct cgroup_root *root;
+	struct cgroup *cgrp;
+	int hierarchy_id = 1;
+	int ret;
+
+	cgroup_lock();
+	spin_lock_irq(&css_set_lock);
+
+	root = idr_get_next(&cgroup_hierarchy_idr, &hierarchy_id);
+
+	if (root) {
+		cgrp = task_cgroup_from_root(task, root);
+		ret = cgroup_path_ns_locked(cgrp, buf, buflen, &init_cgroup_ns);
+	} else {
+		/* if no hierarchy exists, everyone is in "/" */
+		ret = strscpy(buf, "/", buflen);
+	}
+
+	spin_unlock_irq(&css_set_lock);
+	cgroup_unlock();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(task_cgroup_path);
+
+/**
+ * cgroup_attach_lock - Lock for ->attach()
+ * @lock_threadgroup: whether to down_write cgroup_threadgroup_rwsem
+ *
+ * cgroup migration sometimes needs to stabilize threadgroups against forks and
+ * exits by write-locking cgroup_threadgroup_rwsem. However, some ->attach()
+ * implementations (e.g. cpuset), also need to disable CPU hotplug.
+ * Unfortunately, letting ->attach() operations acquire cpus_read_lock() can
+ * lead to deadlocks.
+ *
+ * Bringing up a CPU may involve creating and destroying tasks which requires
+ * read-locking threadgroup_rwsem, so threadgroup_rwsem nests inside
+ * cpus_read_lock(). If we call an ->attach() which acquires the cpus lock while
+ * write-locking threadgroup_rwsem, the locking order is reversed and we end up
+ * waiting for an on-going CPU hotplug operation which in turn is waiting for
+ * the threadgroup_rwsem to be released to create new tasks. For more details:
+ *
+ *   http://lkml.kernel.org/r/20220711174629.uehfmqegcwn2lqzu@wubuntu
+ *
+ * Resolve the situation by always acquiring cpus_read_lock() before optionally
+ * write-locking cgroup_threadgroup_rwsem. This allows ->attach() to assume that
+ * CPU hotplug is disabled on entry.
+ */
+void cgroup_attach_lock(bool lock_threadgroup)
+{
+	cpus_read_lock();
+	if (lock_threadgroup)
+		percpu_down_write(&cgroup_threadgroup_rwsem);
+}
+
+/**
+ * cgroup_attach_unlock - Undo cgroup_attach_lock()
+ * @lock_threadgroup: whether to up_write cgroup_threadgroup_rwsem
+ */
+void cgroup_attach_unlock(bool lock_threadgroup)
+{
+	if (lock_threadgroup)
+		percpu_up_write(&cgroup_threadgroup_rwsem);
+	cpus_read_unlock();
+}
+
+/**
+ * cgroup_migrate_add_task - add a migration target task to a migration context
+ * @task: target task
+ * @mgctx: target migration context
+ *
+ * Add @task, which is a migration target, to @mgctx->tset.  This function
+ * becomes noop if @task doesn't need to be migrated.  @task's css_set
+ * should have been added as a migration source and @task->cg_list will be
+ * moved from the css_set's tasks list to mg_tasks one.
+ */
+static void cgroup_migrate_add_task(struct task_struct *task,
+				    struct cgroup_mgctx *mgctx)
+{
+	struct css_set *cset;
+
+	lockdep_assert_held(&css_set_lock);
+
+	/* @task either already exited or can't exit until the end */
+	if (task->flags & PF_EXITING)
+		return;
+
+	/* cgroup_threadgroup_rwsem protects racing against forks */
+	WARN_ON_ONCE(list_empty(&task->cg_list));
+
+	cset = task_css_set(task);
+	if (!cset->mg_src_cgrp)
+		return;
+
+	mgctx->tset.nr_tasks++;
+
+	list_move_tail(&task->cg_list, &cset->mg_tasks);
+	if (list_empty(&cset->mg_node))
+		list_add_tail(&cset->mg_node,
+			      &mgctx->tset.src_csets);
+	if (list_empty(&cset->mg_dst_cset->mg_node))
+		list_add_tail(&cset->mg_dst_cset->mg_node,
+			      &mgctx->tset.dst_csets);
+}
+
+/**
+ * cgroup_taskset_first - reset taskset and return the first task
+ * @tset: taskset of interest
+ * @dst_cssp: output variable for the destination css
+ *
+ * @tset iteration is initialized and the first task is returned.
+ */
+struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
+					 struct cgroup_subsys_state **dst_cssp)
+{
+	tset->cur_cset = list_first_entry(tset->csets, struct css_set, mg_node);
+	tset->cur_task = NULL;
+
+	return cgroup_taskset_next(tset, dst_cssp);
+}
+
+/**
+ * cgroup_taskset_next - iterate to the next task in taskset
+ * @tset: taskset of interest
+ * @dst_cssp: output variable for the destination css
+ *
+ * Return the next task in @tset.  Iteration must have been initialized
+ * with cgroup_taskset_first().
+ */
+struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
+					struct cgroup_subsys_state **dst_cssp)
+{
+	struct css_set *cset = tset->cur_cset;
+	struct task_struct *task = tset->cur_task;
+
+	while (CGROUP_HAS_SUBSYS_CONFIG && &cset->mg_node != tset->csets) {
+		if (!task)
+			task = list_first_entry(&cset->mg_tasks,
+						struct task_struct, cg_list);
+		else
+			task = list_next_entry(task, cg_list);
+
+		if (&task->cg_list != &cset->mg_tasks) {
+			tset->cur_cset = cset;
+			tset->cur_task = task;
+
+			/*
+			 * This function may be called both before and
+			 * after cgroup_taskset_migrate().  The two cases
+			 * can be distinguished by looking at whether @cset
+			 * has its ->mg_dst_cset set.
+			 */
+			if (cset->mg_dst_cset)
+				*dst_cssp = cset->mg_dst_cset->subsys[tset->ssid];
+			else
+				*dst_cssp = cset->subsys[tset->ssid];
+
+			return task;
+		}
+
+		cset = list_next_entry(cset, mg_node);
+		task = NULL;
+	}
+
+	return NULL;
+}
+
+/**
+ * cgroup_migrate_execute - migrate a taskset
+ * @mgctx: migration context
+ *
+ * Migrate tasks in @mgctx as setup by migration preparation functions.
+ * This function fails iff one of the ->can_attach callbacks fails and
+ * guarantees that either all or none of the tasks in @mgctx are migrated.
+ * @mgctx is consumed regardless of success.
+ */
+static int cgroup_migrate_execute(struct cgroup_mgctx *mgctx)
+{
+	struct cgroup_taskset *tset = &mgctx->tset;
+	struct cgroup_subsys *ss;
+	struct task_struct *task, *tmp_task;
+	struct css_set *cset, *tmp_cset;
+	int ssid, failed_ssid, ret;
+
+	/* check that we can legitimately attach to the cgroup */
+	if (tset->nr_tasks) {
+		do_each_subsys_mask(ss, ssid, mgctx->ss_mask) {
+			if (ss->can_attach) {
+				tset->ssid = ssid;
+				ret = ss->can_attach(tset);
+				if (ret) {
+					failed_ssid = ssid;
+					goto out_cancel_attach;
+				}
+			}
+		} while_each_subsys_mask();
+	}
+
+	/*
+	 * Now that we're guaranteed success, proceed to move all tasks to
+	 * the new cgroup.  There are no failure cases after here, so this
+	 * is the commit point.
+	 */
+	spin_lock_irq(&css_set_lock);
+	list_for_each_entry(cset, &tset->src_csets, mg_node) {
+		list_for_each_entry_safe(task, tmp_task, &cset->mg_tasks, cg_list) {
+			struct css_set *from_cset = task_css_set(task);
+			struct css_set *to_cset = cset->mg_dst_cset;
+
+			get_css_set(to_cset);
+			to_cset->nr_tasks++;
+			css_set_move_task(task, from_cset, to_cset, true);
+			from_cset->nr_tasks--;
+			/*
+			 * If the source or destination cgroup is frozen,
+			 * the task might require to change its state.
+			 */
+			cgroup_freezer_migrate_task(task, from_cset->dfl_cgrp,
+						    to_cset->dfl_cgrp);
+			put_css_set_locked(from_cset);
+
+		}
+	}
+	spin_unlock_irq(&css_set_lock);
+
+	/*
+	 * Migration is committed, all target tasks are now on dst_csets.
+	 * Nothing is sensitive to fork() after this point.  Notify
+	 * controllers that migration is complete.
+	 */
+	tset->csets = &tset->dst_csets;
+
+	if (tset->nr_tasks) {
+		do_each_subsys_mask(ss, ssid, mgctx->ss_mask) {
+			if (ss->attach) {
+				tset->ssid = ssid;
+				ss->attach(tset);
+			}
+		} while_each_subsys_mask();
+	}
+
+	ret = 0;
+	goto out_release_tset;
+
+out_cancel_attach:
+	if (tset->nr_tasks) {
+		do_each_subsys_mask(ss, ssid, mgctx->ss_mask) {
+			if (ssid == failed_ssid)
+				break;
+			if (ss->cancel_attach) {
+				tset->ssid = ssid;
+				ss->cancel_attach(tset);
+			}
+		} while_each_subsys_mask();
+	}
+out_release_tset:
+	spin_lock_irq(&css_set_lock);
+	list_splice_init(&tset->dst_csets, &tset->src_csets);
+	list_for_each_entry_safe(cset, tmp_cset, &tset->src_csets, mg_node) {
+		list_splice_tail_init(&cset->mg_tasks, &cset->tasks);
+		list_del_init(&cset->mg_node);
+	}
+	spin_unlock_irq(&css_set_lock);
+
+	/*
+	 * Re-initialize the cgroup_taskset structure in case it is reused
+	 * again in another cgroup_migrate_add_task()/cgroup_migrate_execute()
+	 * iteration.
+	 */
+	tset->nr_tasks = 0;
+	tset->csets    = &tset->src_csets;
+	return ret;
+}
+
+/**
+ * cgroup_migrate_vet_dst - verify whether a cgroup can be migration destination
+ * @dst_cgrp: destination cgroup to test
+ *
+ * On the default hierarchy, except for the mixable, (possible) thread root
+ * and threaded cgroups, subtree_control must be zero for migration
+ * destination cgroups with tasks so that child cgroups don't compete
+ * against tasks.
+ */
+int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp)
+{
+	/* v1 doesn't have any restriction */
+	if (!cgroup_on_dfl(dst_cgrp))
+		return 0;
+
+	/* verify @dst_cgrp can host resources */
+	if (!cgroup_is_valid_domain(dst_cgrp->dom_cgrp))
+		return -EOPNOTSUPP;
+
+	/*
+	 * If @dst_cgrp is already or can become a thread root or is
+	 * threaded, it doesn't matter.
+	 */
+	if (cgroup_can_be_thread_root(dst_cgrp) || cgroup_is_threaded(dst_cgrp))
+		return 0;
+
+	/* apply no-internal-process constraint */
+	if (dst_cgrp->subtree_control)
+		return -EBUSY;
+
+	return 0;
+}
+
+/**
+ * cgroup_migrate_finish - cleanup after attach
+ * @mgctx: migration context
+ *
+ * Undo cgroup_migrate_add_src() and cgroup_migrate_prepare_dst().  See
+ * those functions for details.
+ */
+void cgroup_migrate_finish(struct cgroup_mgctx *mgctx)
+{
+	struct css_set *cset, *tmp_cset;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	spin_lock_irq(&css_set_lock);
+
+	list_for_each_entry_safe(cset, tmp_cset, &mgctx->preloaded_src_csets,
+				 mg_src_preload_node) {
+		cset->mg_src_cgrp = NULL;
+		cset->mg_dst_cgrp = NULL;
+		cset->mg_dst_cset = NULL;
+		list_del_init(&cset->mg_src_preload_node);
+		put_css_set_locked(cset);
+	}
+
+	list_for_each_entry_safe(cset, tmp_cset, &mgctx->preloaded_dst_csets,
+				 mg_dst_preload_node) {
+		cset->mg_src_cgrp = NULL;
+		cset->mg_dst_cgrp = NULL;
+		cset->mg_dst_cset = NULL;
+		list_del_init(&cset->mg_dst_preload_node);
+		put_css_set_locked(cset);
+	}
+
+	spin_unlock_irq(&css_set_lock);
+}
+
+/**
+ * cgroup_migrate_add_src - add a migration source css_set
+ * @src_cset: the source css_set to add
+ * @dst_cgrp: the destination cgroup
+ * @mgctx: migration context
+ *
+ * Tasks belonging to @src_cset are about to be migrated to @dst_cgrp.  Pin
+ * @src_cset and add it to @mgctx->src_csets, which should later be cleaned
+ * up by cgroup_migrate_finish().
+ *
+ * This function may be called without holding cgroup_threadgroup_rwsem
+ * even if the target is a process.  Threads may be created and destroyed
+ * but as long as cgroup_mutex is not dropped, no new css_set can be put
+ * into play and the preloaded css_sets are guaranteed to cover all
+ * migrations.
+ */
+void cgroup_migrate_add_src(struct css_set *src_cset,
+			    struct cgroup *dst_cgrp,
+			    struct cgroup_mgctx *mgctx)
+{
+	struct cgroup *src_cgrp;
+
+	lockdep_assert_held(&cgroup_mutex);
+	lockdep_assert_held(&css_set_lock);
+
+	/*
+	 * If ->dead, @src_set is associated with one or more dead cgroups
+	 * and doesn't contain any migratable tasks.  Ignore it early so
+	 * that the rest of migration path doesn't get confused by it.
+	 */
+	if (src_cset->dead)
+		return;
+
+	if (!list_empty(&src_cset->mg_src_preload_node))
+		return;
+
+	src_cgrp = cset_cgroup_from_root(src_cset, dst_cgrp->root);
+
+	WARN_ON(src_cset->mg_src_cgrp);
+	WARN_ON(src_cset->mg_dst_cgrp);
+	WARN_ON(!list_empty(&src_cset->mg_tasks));
+	WARN_ON(!list_empty(&src_cset->mg_node));
+
+	src_cset->mg_src_cgrp = src_cgrp;
+	src_cset->mg_dst_cgrp = dst_cgrp;
+	get_css_set(src_cset);
+	list_add_tail(&src_cset->mg_src_preload_node, &mgctx->preloaded_src_csets);
+}
+
+/**
+ * cgroup_migrate_prepare_dst - prepare destination css_sets for migration
+ * @mgctx: migration context
+ *
+ * Tasks are about to be moved and all the source css_sets have been
+ * preloaded to @mgctx->preloaded_src_csets.  This function looks up and
+ * pins all destination css_sets, links each to its source, and append them
+ * to @mgctx->preloaded_dst_csets.
+ *
+ * This function must be called after cgroup_migrate_add_src() has been
+ * called on each migration source css_set.  After migration is performed
+ * using cgroup_migrate(), cgroup_migrate_finish() must be called on
+ * @mgctx.
+ */
+int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx)
+{
+	struct css_set *src_cset, *tmp_cset;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	/* look up the dst cset for each src cset and link it to src */
+	list_for_each_entry_safe(src_cset, tmp_cset, &mgctx->preloaded_src_csets,
+				 mg_src_preload_node) {
+		struct css_set *dst_cset;
+		struct cgroup_subsys *ss;
+		int ssid;
+
+		dst_cset = find_css_set(src_cset, src_cset->mg_dst_cgrp);
+		if (!dst_cset)
+			return -ENOMEM;
+
+		WARN_ON_ONCE(src_cset->mg_dst_cset || dst_cset->mg_dst_cset);
+
+		/*
+		 * If src cset equals dst, it's noop.  Drop the src.
+		 * cgroup_migrate() will skip the cset too.  Note that we
+		 * can't handle src == dst as some nodes are used by both.
+		 */
+		if (src_cset == dst_cset) {
+			src_cset->mg_src_cgrp = NULL;
+			src_cset->mg_dst_cgrp = NULL;
+			list_del_init(&src_cset->mg_src_preload_node);
+			put_css_set(src_cset);
+			put_css_set(dst_cset);
+			continue;
+		}
+
+		src_cset->mg_dst_cset = dst_cset;
+
+		if (list_empty(&dst_cset->mg_dst_preload_node))
+			list_add_tail(&dst_cset->mg_dst_preload_node,
+				      &mgctx->preloaded_dst_csets);
+		else
+			put_css_set(dst_cset);
+
+		for_each_subsys(ss, ssid)
+			if (src_cset->subsys[ssid] != dst_cset->subsys[ssid])
+				mgctx->ss_mask |= 1 << ssid;
+	}
+
+	return 0;
+}
+
+/**
+ * cgroup_migrate - migrate a process or task to a cgroup
+ * @leader: the leader of the process or the task to migrate
+ * @threadgroup: whether @leader points to the whole process or a single task
+ * @mgctx: migration context
+ *
+ * Migrate a process or task denoted by @leader.  If migrating a process,
+ * the caller must be holding cgroup_threadgroup_rwsem.  The caller is also
+ * responsible for invoking cgroup_migrate_add_src() and
+ * cgroup_migrate_prepare_dst() on the targets before invoking this
+ * function and following up with cgroup_migrate_finish().
+ *
+ * As long as a controller's ->can_attach() doesn't fail, this function is
+ * guaranteed to succeed.  This means that, excluding ->can_attach()
+ * failure, when migrating multiple targets, the success or failure can be
+ * decided for all targets by invoking group_migrate_prepare_dst() before
+ * actually starting migrating.
+ */
+int cgroup_migrate(struct task_struct *leader, bool threadgroup,
+		   struct cgroup_mgctx *mgctx)
+{
+	struct task_struct *task;
+
+	/*
+	 * Prevent freeing of tasks while we take a snapshot. Tasks that are
+	 * already PF_EXITING could be freed from underneath us unless we
+	 * take an rcu_read_lock.
+	 */
+	spin_lock_irq(&css_set_lock);
+	rcu_read_lock();
+	task = leader;
+	do {
+		cgroup_migrate_add_task(task, mgctx);
+		if (!threadgroup)
+			break;
+	} while_each_thread(leader, task);
+	rcu_read_unlock();
+	spin_unlock_irq(&css_set_lock);
+
+	return cgroup_migrate_execute(mgctx);
+}
+
+/**
+ * cgroup_attach_task - attach a task or a whole threadgroup to a cgroup
+ * @dst_cgrp: the cgroup to attach to
+ * @leader: the task or the leader of the threadgroup to be attached
+ * @threadgroup: attach the whole threadgroup?
+ *
+ * Call holding cgroup_mutex and cgroup_threadgroup_rwsem.
+ */
+int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
+		       bool threadgroup)
+{
+	DEFINE_CGROUP_MGCTX(mgctx);
+	struct task_struct *task;
+	int ret = 0;
+
+	/* look up all src csets */
+	spin_lock_irq(&css_set_lock);
+	rcu_read_lock();
+	task = leader;
+	do {
+		cgroup_migrate_add_src(task_css_set(task), dst_cgrp, &mgctx);
+		if (!threadgroup)
+			break;
+	} while_each_thread(leader, task);
+	rcu_read_unlock();
+	spin_unlock_irq(&css_set_lock);
+
+	/* prepare dst csets and commit */
+	ret = cgroup_migrate_prepare_dst(&mgctx);
+	if (!ret)
+		ret = cgroup_migrate(leader, threadgroup, &mgctx);
+
+	cgroup_migrate_finish(&mgctx);
+
+	if (!ret)
+		TRACE_CGROUP_PATH(attach_task, dst_cgrp, leader, threadgroup);
+
+	return ret;
+}
+
+struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup,
+					     bool *threadgroup_locked)
+{
+	struct task_struct *tsk;
+	pid_t pid;
+
+	if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * If we migrate a single thread, we don't care about threadgroup
+	 * stability. If the thread is `current`, it won't exit(2) under our
+	 * hands or change PID through exec(2). We exclude
+	 * cgroup_update_dfl_csses and other cgroup_{proc,thread}s_write
+	 * callers by cgroup_mutex.
+	 * Therefore, we can skip the global lock.
+	 */
+	lockdep_assert_held(&cgroup_mutex);
+	*threadgroup_locked = pid || threadgroup;
+	cgroup_attach_lock(*threadgroup_locked);
+
+	rcu_read_lock();
+	if (pid) {
+		tsk = find_task_by_vpid(pid);
+		if (!tsk) {
+			tsk = ERR_PTR(-ESRCH);
+			goto out_unlock_threadgroup;
+		}
+	} else {
+		tsk = current;
+	}
+
+	if (threadgroup)
+		tsk = tsk->group_leader;
+
+	/*
+	 * kthreads may acquire PF_NO_SETAFFINITY during initialization.
+	 * If userland migrates such a kthread to a non-root cgroup, it can
+	 * become trapped in a cpuset, or RT kthread may be born in a
+	 * cgroup with no rt_runtime allocated.  Just say no.
+	 */
+	if (tsk->no_cgroup_migration || (tsk->flags & PF_NO_SETAFFINITY)) {
+		tsk = ERR_PTR(-EINVAL);
+		goto out_unlock_threadgroup;
+	}
+
+	get_task_struct(tsk);
+	goto out_unlock_rcu;
+
+out_unlock_threadgroup:
+	cgroup_attach_unlock(*threadgroup_locked);
+	*threadgroup_locked = false;
+out_unlock_rcu:
+	rcu_read_unlock();
+	return tsk;
+}
+
+void cgroup_procs_write_finish(struct task_struct *task, bool threadgroup_locked)
+{
+	struct cgroup_subsys *ss;
+	int ssid;
+
+	/* release reference from cgroup_procs_write_start() */
+	put_task_struct(task);
+
+	cgroup_attach_unlock(threadgroup_locked);
+
+	for_each_subsys(ss, ssid)
+		if (ss->post_attach)
+			ss->post_attach();
+}
+
+static void cgroup_print_ss_mask(struct seq_file *seq, u16 ss_mask)
+{
+	struct cgroup_subsys *ss;
+	bool printed = false;
+	int ssid;
+
+	do_each_subsys_mask(ss, ssid, ss_mask) {
+		if (printed)
+			seq_putc(seq, ' ');
+		seq_puts(seq, ss->name);
+		printed = true;
+	} while_each_subsys_mask();
+	if (printed)
+		seq_putc(seq, '\n');
+}
+
+/* show controllers which are enabled from the parent */
+static int cgroup_controllers_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+
+	cgroup_print_ss_mask(seq, cgroup_control(cgrp));
+	return 0;
+}
+
+/* show controllers which are enabled for a given cgroup's children */
+static int cgroup_subtree_control_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+
+	cgroup_print_ss_mask(seq, cgrp->subtree_control);
+	return 0;
+}
+
+/**
+ * cgroup_update_dfl_csses - update css assoc of a subtree in default hierarchy
+ * @cgrp: root of the subtree to update csses for
+ *
+ * @cgrp's control masks have changed and its subtree's css associations
+ * need to be updated accordingly.  This function looks up all css_sets
+ * which are attached to the subtree, creates the matching updated css_sets
+ * and migrates the tasks to the new ones.
+ */
+static int cgroup_update_dfl_csses(struct cgroup *cgrp)
+{
+	DEFINE_CGROUP_MGCTX(mgctx);
+	struct cgroup_subsys_state *d_css;
+	struct cgroup *dsct;
+	struct css_set *src_cset;
+	bool has_tasks;
+	int ret;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	/* look up all csses currently attached to @cgrp's subtree */
+	spin_lock_irq(&css_set_lock);
+	cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
+		struct cgrp_cset_link *link;
+
+		/*
+		 * As cgroup_update_dfl_csses() is only called by
+		 * cgroup_apply_control(). The csses associated with the
+		 * given cgrp will not be affected by changes made to
+		 * its subtree_control file. We can skip them.
+		 */
+		if (dsct == cgrp)
+			continue;
+
+		list_for_each_entry(link, &dsct->cset_links, cset_link)
+			cgroup_migrate_add_src(link->cset, dsct, &mgctx);
+	}
+	spin_unlock_irq(&css_set_lock);
+
+	/*
+	 * We need to write-lock threadgroup_rwsem while migrating tasks.
+	 * However, if there are no source csets for @cgrp, changing its
+	 * controllers isn't gonna produce any task migrations and the
+	 * write-locking can be skipped safely.
+	 */
+	has_tasks = !list_empty(&mgctx.preloaded_src_csets);
+	cgroup_attach_lock(has_tasks);
+
+	/* NULL dst indicates self on default hierarchy */
+	ret = cgroup_migrate_prepare_dst(&mgctx);
+	if (ret)
+		goto out_finish;
+
+	spin_lock_irq(&css_set_lock);
+	list_for_each_entry(src_cset, &mgctx.preloaded_src_csets,
+			    mg_src_preload_node) {
+		struct task_struct *task, *ntask;
+
+		/* all tasks in src_csets need to be migrated */
+		list_for_each_entry_safe(task, ntask, &src_cset->tasks, cg_list)
+			cgroup_migrate_add_task(task, &mgctx);
+	}
+	spin_unlock_irq(&css_set_lock);
+
+	ret = cgroup_migrate_execute(&mgctx);
+out_finish:
+	cgroup_migrate_finish(&mgctx);
+	cgroup_attach_unlock(has_tasks);
+	return ret;
+}
+
+/**
+ * cgroup_lock_and_drain_offline - lock cgroup_mutex and drain offlined csses
+ * @cgrp: root of the target subtree
+ *
+ * Because css offlining is asynchronous, userland may try to re-enable a
+ * controller while the previous css is still around.  This function grabs
+ * cgroup_mutex and drains the previous css instances of @cgrp's subtree.
+ */
+void cgroup_lock_and_drain_offline(struct cgroup *cgrp)
+	__acquires(&cgroup_mutex)
+{
+	struct cgroup *dsct;
+	struct cgroup_subsys_state *d_css;
+	struct cgroup_subsys *ss;
+	int ssid;
+
+restart:
+	cgroup_lock();
+
+	cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) {
+		for_each_subsys(ss, ssid) {
+			struct cgroup_subsys_state *css = cgroup_css(dsct, ss);
+			DEFINE_WAIT(wait);
+
+			if (!css || !percpu_ref_is_dying(&css->refcnt))
+				continue;
+
+			cgroup_get_live(dsct);
+			prepare_to_wait(&dsct->offline_waitq, &wait,
+					TASK_UNINTERRUPTIBLE);
+
+			cgroup_unlock();
+			schedule();
+			finish_wait(&dsct->offline_waitq, &wait);
+
+			cgroup_put(dsct);
+			goto restart;
+		}
+	}
+}
+
+/**
+ * cgroup_save_control - save control masks and dom_cgrp of a subtree
+ * @cgrp: root of the target subtree
+ *
+ * Save ->subtree_control, ->subtree_ss_mask and ->dom_cgrp to the
+ * respective old_ prefixed fields for @cgrp's subtree including @cgrp
+ * itself.
+ */
+static void cgroup_save_control(struct cgroup *cgrp)
+{
+	struct cgroup *dsct;
+	struct cgroup_subsys_state *d_css;
+
+	cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
+		dsct->old_subtree_control = dsct->subtree_control;
+		dsct->old_subtree_ss_mask = dsct->subtree_ss_mask;
+		dsct->old_dom_cgrp = dsct->dom_cgrp;
+	}
+}
+
+/**
+ * cgroup_propagate_control - refresh control masks of a subtree
+ * @cgrp: root of the target subtree
+ *
+ * For @cgrp and its subtree, ensure ->subtree_ss_mask matches
+ * ->subtree_control and propagate controller availability through the
+ * subtree so that descendants don't have unavailable controllers enabled.
+ */
+static void cgroup_propagate_control(struct cgroup *cgrp)
+{
+	struct cgroup *dsct;
+	struct cgroup_subsys_state *d_css;
+
+	cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
+		dsct->subtree_control &= cgroup_control(dsct);
+		dsct->subtree_ss_mask =
+			cgroup_calc_subtree_ss_mask(dsct->subtree_control,
+						    cgroup_ss_mask(dsct));
+	}
+}
+
+/**
+ * cgroup_restore_control - restore control masks and dom_cgrp of a subtree
+ * @cgrp: root of the target subtree
+ *
+ * Restore ->subtree_control, ->subtree_ss_mask and ->dom_cgrp from the
+ * respective old_ prefixed fields for @cgrp's subtree including @cgrp
+ * itself.
+ */
+static void cgroup_restore_control(struct cgroup *cgrp)
+{
+	struct cgroup *dsct;
+	struct cgroup_subsys_state *d_css;
+
+	cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) {
+		dsct->subtree_control = dsct->old_subtree_control;
+		dsct->subtree_ss_mask = dsct->old_subtree_ss_mask;
+		dsct->dom_cgrp = dsct->old_dom_cgrp;
+	}
+}
+
+static bool css_visible(struct cgroup_subsys_state *css)
+{
+	struct cgroup_subsys *ss = css->ss;
+	struct cgroup *cgrp = css->cgroup;
+
+	if (cgroup_control(cgrp) & (1 << ss->id))
+		return true;
+	if (!(cgroup_ss_mask(cgrp) & (1 << ss->id)))
+		return false;
+	return cgroup_on_dfl(cgrp) && ss->implicit_on_dfl;
+}
+
+/**
+ * cgroup_apply_control_enable - enable or show csses according to control
+ * @cgrp: root of the target subtree
+ *
+ * Walk @cgrp's subtree and create new csses or make the existing ones
+ * visible.  A css is created invisible if it's being implicitly enabled
+ * through dependency.  An invisible css is made visible when the userland
+ * explicitly enables it.
+ *
+ * Returns 0 on success, -errno on failure.  On failure, csses which have
+ * been processed already aren't cleaned up.  The caller is responsible for
+ * cleaning up with cgroup_apply_control_disable().
+ */
+static int cgroup_apply_control_enable(struct cgroup *cgrp)
+{
+	struct cgroup *dsct;
+	struct cgroup_subsys_state *d_css;
+	struct cgroup_subsys *ss;
+	int ssid, ret;
+
+	cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
+		for_each_subsys(ss, ssid) {
+			struct cgroup_subsys_state *css = cgroup_css(dsct, ss);
+
+			if (!(cgroup_ss_mask(dsct) & (1 << ss->id)))
+				continue;
+
+			if (!css) {
+				css = css_create(dsct, ss);
+				if (IS_ERR(css))
+					return PTR_ERR(css);
+			}
+
+			WARN_ON_ONCE(percpu_ref_is_dying(&css->refcnt));
+
+			if (css_visible(css)) {
+				ret = css_populate_dir(css);
+				if (ret)
+					return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * cgroup_apply_control_disable - kill or hide csses according to control
+ * @cgrp: root of the target subtree
+ *
+ * Walk @cgrp's subtree and kill and hide csses so that they match
+ * cgroup_ss_mask() and cgroup_visible_mask().
+ *
+ * A css is hidden when the userland requests it to be disabled while other
+ * subsystems are still depending on it.  The css must not actively control
+ * resources and be in the vanilla state if it's made visible again later.
+ * Controllers which may be depended upon should provide ->css_reset() for
+ * this purpose.
+ */
+static void cgroup_apply_control_disable(struct cgroup *cgrp)
+{
+	struct cgroup *dsct;
+	struct cgroup_subsys_state *d_css;
+	struct cgroup_subsys *ss;
+	int ssid;
+
+	cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) {
+		for_each_subsys(ss, ssid) {
+			struct cgroup_subsys_state *css = cgroup_css(dsct, ss);
+
+			if (!css)
+				continue;
+
+			WARN_ON_ONCE(percpu_ref_is_dying(&css->refcnt));
+
+			if (css->parent &&
+			    !(cgroup_ss_mask(dsct) & (1 << ss->id))) {
+				kill_css(css);
+			} else if (!css_visible(css)) {
+				css_clear_dir(css);
+				if (ss->css_reset)
+					ss->css_reset(css);
+			}
+		}
+	}
+}
+
+/**
+ * cgroup_apply_control - apply control mask updates to the subtree
+ * @cgrp: root of the target subtree
+ *
+ * subsystems can be enabled and disabled in a subtree using the following
+ * steps.
+ *
+ * 1. Call cgroup_save_control() to stash the current state.
+ * 2. Update ->subtree_control masks in the subtree as desired.
+ * 3. Call cgroup_apply_control() to apply the changes.
+ * 4. Optionally perform other related operations.
+ * 5. Call cgroup_finalize_control() to finish up.
+ *
+ * This function implements step 3 and propagates the mask changes
+ * throughout @cgrp's subtree, updates csses accordingly and perform
+ * process migrations.
+ */
+static int cgroup_apply_control(struct cgroup *cgrp)
+{
+	int ret;
+
+	cgroup_propagate_control(cgrp);
+
+	ret = cgroup_apply_control_enable(cgrp);
+	if (ret)
+		return ret;
+
+	/*
+	 * At this point, cgroup_e_css_by_mask() results reflect the new csses
+	 * making the following cgroup_update_dfl_csses() properly update
+	 * css associations of all tasks in the subtree.
+	 */
+	return cgroup_update_dfl_csses(cgrp);
+}
+
+/**
+ * cgroup_finalize_control - finalize control mask update
+ * @cgrp: root of the target subtree
+ * @ret: the result of the update
+ *
+ * Finalize control mask update.  See cgroup_apply_control() for more info.
+ */
+static void cgroup_finalize_control(struct cgroup *cgrp, int ret)
+{
+	if (ret) {
+		cgroup_restore_control(cgrp);
+		cgroup_propagate_control(cgrp);
+	}
+
+	cgroup_apply_control_disable(cgrp);
+}
+
+static int cgroup_vet_subtree_control_enable(struct cgroup *cgrp, u16 enable)
+{
+	u16 domain_enable = enable & ~cgrp_dfl_threaded_ss_mask;
+
+	/* if nothing is getting enabled, nothing to worry about */
+	if (!enable)
+		return 0;
+
+	/* can @cgrp host any resources? */
+	if (!cgroup_is_valid_domain(cgrp->dom_cgrp))
+		return -EOPNOTSUPP;
+
+	/* mixables don't care */
+	if (cgroup_is_mixable(cgrp))
+		return 0;
+
+	if (domain_enable) {
+		/* can't enable domain controllers inside a thread subtree */
+		if (cgroup_is_thread_root(cgrp) || cgroup_is_threaded(cgrp))
+			return -EOPNOTSUPP;
+	} else {
+		/*
+		 * Threaded controllers can handle internal competitions
+		 * and are always allowed inside a (prospective) thread
+		 * subtree.
+		 */
+		if (cgroup_can_be_thread_root(cgrp) || cgroup_is_threaded(cgrp))
+			return 0;
+	}
+
+	/*
+	 * Controllers can't be enabled for a cgroup with tasks to avoid
+	 * child cgroups competing against tasks.
+	 */
+	if (cgroup_has_tasks(cgrp))
+		return -EBUSY;
+
+	return 0;
+}
+
+/* change the enabled child controllers for a cgroup in the default hierarchy */
+static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of,
+					    char *buf, size_t nbytes,
+					    loff_t off)
+{
+	u16 enable = 0, disable = 0;
+	struct cgroup *cgrp, *child;
+	struct cgroup_subsys *ss;
+	char *tok;
+	int ssid, ret;
+
+	/*
+	 * Parse input - space separated list of subsystem names prefixed
+	 * with either + or -.
+	 */
+	buf = strstrip(buf);
+	while ((tok = strsep(&buf, " "))) {
+		if (tok[0] == '\0')
+			continue;
+		do_each_subsys_mask(ss, ssid, ~cgrp_dfl_inhibit_ss_mask) {
+			if (!cgroup_ssid_enabled(ssid) ||
+			    strcmp(tok + 1, ss->name))
+				continue;
+
+			if (*tok == '+') {
+				enable |= 1 << ssid;
+				disable &= ~(1 << ssid);
+			} else if (*tok == '-') {
+				disable |= 1 << ssid;
+				enable &= ~(1 << ssid);
+			} else {
+				return -EINVAL;
+			}
+			break;
+		} while_each_subsys_mask();
+		if (ssid == CGROUP_SUBSYS_COUNT)
+			return -EINVAL;
+	}
+
+	cgrp = cgroup_kn_lock_live(of->kn, true);
+	if (!cgrp)
+		return -ENODEV;
+
+	for_each_subsys(ss, ssid) {
+		if (enable & (1 << ssid)) {
+			if (cgrp->subtree_control & (1 << ssid)) {
+				enable &= ~(1 << ssid);
+				continue;
+			}
+
+			if (!(cgroup_control(cgrp) & (1 << ssid))) {
+				ret = -ENOENT;
+				goto out_unlock;
+			}
+		} else if (disable & (1 << ssid)) {
+			if (!(cgrp->subtree_control & (1 << ssid))) {
+				disable &= ~(1 << ssid);
+				continue;
+			}
+
+			/* a child has it enabled? */
+			cgroup_for_each_live_child(child, cgrp) {
+				if (child->subtree_control & (1 << ssid)) {
+					ret = -EBUSY;
+					goto out_unlock;
+				}
+			}
+		}
+	}
+
+	if (!enable && !disable) {
+		ret = 0;
+		goto out_unlock;
+	}
+
+	ret = cgroup_vet_subtree_control_enable(cgrp, enable);
+	if (ret)
+		goto out_unlock;
+
+	/* save and update control masks and prepare csses */
+	cgroup_save_control(cgrp);
+
+	cgrp->subtree_control |= enable;
+	cgrp->subtree_control &= ~disable;
+
+	ret = cgroup_apply_control(cgrp);
+	cgroup_finalize_control(cgrp, ret);
+	if (ret)
+		goto out_unlock;
+
+	kernfs_activate(cgrp->kn);
+out_unlock:
+	cgroup_kn_unlock(of->kn);
+	return ret ?: nbytes;
+}
+
+/**
+ * cgroup_enable_threaded - make @cgrp threaded
+ * @cgrp: the target cgroup
+ *
+ * Called when "threaded" is written to the cgroup.type interface file and
+ * tries to make @cgrp threaded and join the parent's resource domain.
+ * This function is never called on the root cgroup as cgroup.type doesn't
+ * exist on it.
+ */
+static int cgroup_enable_threaded(struct cgroup *cgrp)
+{
+	struct cgroup *parent = cgroup_parent(cgrp);
+	struct cgroup *dom_cgrp = parent->dom_cgrp;
+	struct cgroup *dsct;
+	struct cgroup_subsys_state *d_css;
+	int ret;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	/* noop if already threaded */
+	if (cgroup_is_threaded(cgrp))
+		return 0;
+
+	/*
+	 * If @cgroup is populated or has domain controllers enabled, it
+	 * can't be switched.  While the below cgroup_can_be_thread_root()
+	 * test can catch the same conditions, that's only when @parent is
+	 * not mixable, so let's check it explicitly.
+	 */
+	if (cgroup_is_populated(cgrp) ||
+	    cgrp->subtree_control & ~cgrp_dfl_threaded_ss_mask)
+		return -EOPNOTSUPP;
+
+	/* we're joining the parent's domain, ensure its validity */
+	if (!cgroup_is_valid_domain(dom_cgrp) ||
+	    !cgroup_can_be_thread_root(dom_cgrp))
+		return -EOPNOTSUPP;
+
+	/*
+	 * The following shouldn't cause actual migrations and should
+	 * always succeed.
+	 */
+	cgroup_save_control(cgrp);
+
+	cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp)
+		if (dsct == cgrp || cgroup_is_threaded(dsct))
+			dsct->dom_cgrp = dom_cgrp;
+
+	ret = cgroup_apply_control(cgrp);
+	if (!ret)
+		parent->nr_threaded_children++;
+
+	cgroup_finalize_control(cgrp, ret);
+	return ret;
+}
+
+static int cgroup_type_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+
+	if (cgroup_is_threaded(cgrp))
+		seq_puts(seq, "threaded\n");
+	else if (!cgroup_is_valid_domain(cgrp))
+		seq_puts(seq, "domain invalid\n");
+	else if (cgroup_is_thread_root(cgrp))
+		seq_puts(seq, "domain threaded\n");
+	else
+		seq_puts(seq, "domain\n");
+
+	return 0;
+}
+
+static ssize_t cgroup_type_write(struct kernfs_open_file *of, char *buf,
+				 size_t nbytes, loff_t off)
+{
+	struct cgroup *cgrp;
+	int ret;
+
+	/* only switching to threaded mode is supported */
+	if (strcmp(strstrip(buf), "threaded"))
+		return -EINVAL;
+
+	/* drain dying csses before we re-apply (threaded) subtree control */
+	cgrp = cgroup_kn_lock_live(of->kn, true);
+	if (!cgrp)
+		return -ENOENT;
+
+	/* threaded can only be enabled */
+	ret = cgroup_enable_threaded(cgrp);
+
+	cgroup_kn_unlock(of->kn);
+	return ret ?: nbytes;
+}
+
+static int cgroup_max_descendants_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+	int descendants = READ_ONCE(cgrp->max_descendants);
+
+	if (descendants == INT_MAX)
+		seq_puts(seq, "max\n");
+	else
+		seq_printf(seq, "%d\n", descendants);
+
+	return 0;
+}
+
+static ssize_t cgroup_max_descendants_write(struct kernfs_open_file *of,
+					   char *buf, size_t nbytes, loff_t off)
+{
+	struct cgroup *cgrp;
+	int descendants;
+	ssize_t ret;
+
+	buf = strstrip(buf);
+	if (!strcmp(buf, "max")) {
+		descendants = INT_MAX;
+	} else {
+		ret = kstrtoint(buf, 0, &descendants);
+		if (ret)
+			return ret;
+	}
+
+	if (descendants < 0)
+		return -ERANGE;
+
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENOENT;
+
+	cgrp->max_descendants = descendants;
+
+	cgroup_kn_unlock(of->kn);
+
+	return nbytes;
+}
+
+static int cgroup_max_depth_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+	int depth = READ_ONCE(cgrp->max_depth);
+
+	if (depth == INT_MAX)
+		seq_puts(seq, "max\n");
+	else
+		seq_printf(seq, "%d\n", depth);
+
+	return 0;
+}
+
+static ssize_t cgroup_max_depth_write(struct kernfs_open_file *of,
+				      char *buf, size_t nbytes, loff_t off)
+{
+	struct cgroup *cgrp;
+	ssize_t ret;
+	int depth;
+
+	buf = strstrip(buf);
+	if (!strcmp(buf, "max")) {
+		depth = INT_MAX;
+	} else {
+		ret = kstrtoint(buf, 0, &depth);
+		if (ret)
+			return ret;
+	}
+
+	if (depth < 0)
+		return -ERANGE;
+
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENOENT;
+
+	cgrp->max_depth = depth;
+
+	cgroup_kn_unlock(of->kn);
+
+	return nbytes;
+}
+
+static int cgroup_events_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+
+	seq_printf(seq, "populated %d\n", cgroup_is_populated(cgrp));
+	seq_printf(seq, "frozen %d\n", test_bit(CGRP_FROZEN, &cgrp->flags));
+
+	return 0;
+}
+
+static int cgroup_stat_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgroup = seq_css(seq)->cgroup;
+
+	seq_printf(seq, "nr_descendants %d\n",
+		   cgroup->nr_descendants);
+	seq_printf(seq, "nr_dying_descendants %d\n",
+		   cgroup->nr_dying_descendants);
+
+	return 0;
+}
+
+static int __maybe_unused cgroup_extra_stat_show(struct seq_file *seq,
+						 struct cgroup *cgrp, int ssid)
+{
+	struct cgroup_subsys *ss = cgroup_subsys[ssid];
+	struct cgroup_subsys_state *css;
+	int ret;
+
+	if (!ss->css_extra_stat_show)
+		return 0;
+
+	css = cgroup_tryget_css(cgrp, ss);
+	if (!css)
+		return 0;
+
+	ret = ss->css_extra_stat_show(seq, css);
+	css_put(css);
+	return ret;
+}
+
+static int cpu_stat_show(struct seq_file *seq, void *v)
+{
+	struct cgroup __maybe_unused *cgrp = seq_css(seq)->cgroup;
+	int ret = 0;
+
+	cgroup_base_stat_cputime_show(seq);
+#ifdef CONFIG_CGROUP_SCHED
+	ret = cgroup_extra_stat_show(seq, cgrp, cpu_cgrp_id);
+#endif
+	return ret;
+}
+
+#ifdef CONFIG_PSI
+static int cgroup_io_pressure_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+	struct psi_group *psi = cgroup_psi(cgrp);
+
+	return psi_show(seq, psi, PSI_IO);
+}
+static int cgroup_memory_pressure_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+	struct psi_group *psi = cgroup_psi(cgrp);
+
+	return psi_show(seq, psi, PSI_MEM);
+}
+static int cgroup_cpu_pressure_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+	struct psi_group *psi = cgroup_psi(cgrp);
+
+	return psi_show(seq, psi, PSI_CPU);
+}
+
+static ssize_t pressure_write(struct kernfs_open_file *of, char *buf,
+			      size_t nbytes, enum psi_res res)
+{
+	struct cgroup_file_ctx *ctx = of->priv;
+	struct psi_trigger *new;
+	struct cgroup *cgrp;
+	struct psi_group *psi;
+
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENODEV;
+
+	cgroup_get(cgrp);
+	cgroup_kn_unlock(of->kn);
+
+	/* Allow only one trigger per file descriptor */
+	if (ctx->psi.trigger) {
+		cgroup_put(cgrp);
+		return -EBUSY;
+	}
+
+	psi = cgroup_psi(cgrp);
+	new = psi_trigger_create(psi, buf, res, of->file, of);
+	if (IS_ERR(new)) {
+		cgroup_put(cgrp);
+		return PTR_ERR(new);
+	}
+
+	smp_store_release(&ctx->psi.trigger, new);
+	cgroup_put(cgrp);
+
+	return nbytes;
+}
+
+static ssize_t cgroup_io_pressure_write(struct kernfs_open_file *of,
+					  char *buf, size_t nbytes,
+					  loff_t off)
+{
+	return pressure_write(of, buf, nbytes, PSI_IO);
+}
+
+static ssize_t cgroup_memory_pressure_write(struct kernfs_open_file *of,
+					  char *buf, size_t nbytes,
+					  loff_t off)
+{
+	return pressure_write(of, buf, nbytes, PSI_MEM);
+}
+
+static ssize_t cgroup_cpu_pressure_write(struct kernfs_open_file *of,
+					  char *buf, size_t nbytes,
+					  loff_t off)
+{
+	return pressure_write(of, buf, nbytes, PSI_CPU);
+}
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+static int cgroup_irq_pressure_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+	struct psi_group *psi = cgroup_psi(cgrp);
+
+	return psi_show(seq, psi, PSI_IRQ);
+}
+
+static ssize_t cgroup_irq_pressure_write(struct kernfs_open_file *of,
+					 char *buf, size_t nbytes,
+					 loff_t off)
+{
+	return pressure_write(of, buf, nbytes, PSI_IRQ);
+}
+#endif
+
+static int cgroup_pressure_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+	struct psi_group *psi = cgroup_psi(cgrp);
+
+	seq_printf(seq, "%d\n", psi->enabled);
+
+	return 0;
+}
+
+static ssize_t cgroup_pressure_write(struct kernfs_open_file *of,
+				     char *buf, size_t nbytes,
+				     loff_t off)
+{
+	ssize_t ret;
+	int enable;
+	struct cgroup *cgrp;
+	struct psi_group *psi;
+
+	ret = kstrtoint(strstrip(buf), 0, &enable);
+	if (ret)
+		return ret;
+
+	if (enable < 0 || enable > 1)
+		return -ERANGE;
+
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENOENT;
+
+	psi = cgroup_psi(cgrp);
+	if (psi->enabled != enable) {
+		int i;
+
+		/* show or hide {cpu,memory,io,irq}.pressure files */
+		for (i = 0; i < NR_PSI_RESOURCES; i++)
+			cgroup_file_show(&cgrp->psi_files[i], enable);
+
+		psi->enabled = enable;
+		if (enable)
+			psi_cgroup_restart(psi);
+	}
+
+	cgroup_kn_unlock(of->kn);
+
+	return nbytes;
+}
+
+static __poll_t cgroup_pressure_poll(struct kernfs_open_file *of,
+					  poll_table *pt)
+{
+	struct cgroup_file_ctx *ctx = of->priv;
+
+	return psi_trigger_poll(&ctx->psi.trigger, of->file, pt);
+}
+
+static void cgroup_pressure_release(struct kernfs_open_file *of)
+{
+	struct cgroup_file_ctx *ctx = of->priv;
+
+	psi_trigger_destroy(ctx->psi.trigger);
+}
+
+bool cgroup_psi_enabled(void)
+{
+	if (static_branch_likely(&psi_disabled))
+		return false;
+
+	return (cgroup_feature_disable_mask & (1 << OPT_FEATURE_PRESSURE)) == 0;
+}
+
+#else /* CONFIG_PSI */
+bool cgroup_psi_enabled(void)
+{
+	return false;
+}
+
+#endif /* CONFIG_PSI */
+
+static int cgroup_freeze_show(struct seq_file *seq, void *v)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+
+	seq_printf(seq, "%d\n", cgrp->freezer.freeze);
+
+	return 0;
+}
+
+static ssize_t cgroup_freeze_write(struct kernfs_open_file *of,
+				   char *buf, size_t nbytes, loff_t off)
+{
+	struct cgroup *cgrp;
+	ssize_t ret;
+	int freeze;
+
+	ret = kstrtoint(strstrip(buf), 0, &freeze);
+	if (ret)
+		return ret;
+
+	if (freeze < 0 || freeze > 1)
+		return -ERANGE;
+
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENOENT;
+
+	cgroup_freeze(cgrp, freeze);
+
+	cgroup_kn_unlock(of->kn);
+
+	return nbytes;
+}
+
+static void __cgroup_kill(struct cgroup *cgrp)
+{
+	struct css_task_iter it;
+	struct task_struct *task;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	spin_lock_irq(&css_set_lock);
+	set_bit(CGRP_KILL, &cgrp->flags);
+	spin_unlock_irq(&css_set_lock);
+
+	css_task_iter_start(&cgrp->self, CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED, &it);
+	while ((task = css_task_iter_next(&it))) {
+		/* Ignore kernel threads here. */
+		if (task->flags & PF_KTHREAD)
+			continue;
+
+		/* Skip tasks that are already dying. */
+		if (__fatal_signal_pending(task))
+			continue;
+
+		send_sig(SIGKILL, task, 0);
+	}
+	css_task_iter_end(&it);
+
+	spin_lock_irq(&css_set_lock);
+	clear_bit(CGRP_KILL, &cgrp->flags);
+	spin_unlock_irq(&css_set_lock);
+}
+
+static void cgroup_kill(struct cgroup *cgrp)
+{
+	struct cgroup_subsys_state *css;
+	struct cgroup *dsct;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	cgroup_for_each_live_descendant_pre(dsct, css, cgrp)
+		__cgroup_kill(dsct);
+}
+
+static ssize_t cgroup_kill_write(struct kernfs_open_file *of, char *buf,
+				 size_t nbytes, loff_t off)
+{
+	ssize_t ret = 0;
+	int kill;
+	struct cgroup *cgrp;
+
+	ret = kstrtoint(strstrip(buf), 0, &kill);
+	if (ret)
+		return ret;
+
+	if (kill != 1)
+		return -ERANGE;
+
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENOENT;
+
+	/*
+	 * Killing is a process directed operation, i.e. the whole thread-group
+	 * is taken down so act like we do for cgroup.procs and only make this
+	 * writable in non-threaded cgroups.
+	 */
+	if (cgroup_is_threaded(cgrp))
+		ret = -EOPNOTSUPP;
+	else
+		cgroup_kill(cgrp);
+
+	cgroup_kn_unlock(of->kn);
+
+	return ret ?: nbytes;
+}
+
+static int cgroup_file_open(struct kernfs_open_file *of)
+{
+	struct cftype *cft = of_cft(of);
+	struct cgroup_file_ctx *ctx;
+	int ret;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->ns = current->nsproxy->cgroup_ns;
+	get_cgroup_ns(ctx->ns);
+	of->priv = ctx;
+
+	if (!cft->open)
+		return 0;
+
+	ret = cft->open(of);
+	if (ret) {
+		put_cgroup_ns(ctx->ns);
+		kfree(ctx);
+	}
+	return ret;
+}
+
+static void cgroup_file_release(struct kernfs_open_file *of)
+{
+	struct cftype *cft = of_cft(of);
+	struct cgroup_file_ctx *ctx = of->priv;
+
+	if (cft->release)
+		cft->release(of);
+	put_cgroup_ns(ctx->ns);
+	kfree(ctx);
+}
+
+static ssize_t cgroup_file_write(struct kernfs_open_file *of, char *buf,
+				 size_t nbytes, loff_t off)
+{
+	struct cgroup_file_ctx *ctx = of->priv;
+	struct cgroup *cgrp = of->kn->parent->priv;
+	struct cftype *cft = of_cft(of);
+	struct cgroup_subsys_state *css;
+	int ret;
+
+	if (!nbytes)
+		return 0;
+
+	/*
+	 * If namespaces are delegation boundaries, disallow writes to
+	 * files in an non-init namespace root from inside the namespace
+	 * except for the files explicitly marked delegatable -
+	 * cgroup.procs and cgroup.subtree_control.
+	 */
+	if ((cgrp->root->flags & CGRP_ROOT_NS_DELEGATE) &&
+	    !(cft->flags & CFTYPE_NS_DELEGATABLE) &&
+	    ctx->ns != &init_cgroup_ns && ctx->ns->root_cset->dfl_cgrp == cgrp)
+		return -EPERM;
+
+	if (cft->write)
+		return cft->write(of, buf, nbytes, off);
+
+	/*
+	 * kernfs guarantees that a file isn't deleted with operations in
+	 * flight, which means that the matching css is and stays alive and
+	 * doesn't need to be pinned.  The RCU locking is not necessary
+	 * either.  It's just for the convenience of using cgroup_css().
+	 */
+	rcu_read_lock();
+	css = cgroup_css(cgrp, cft->ss);
+	rcu_read_unlock();
+
+	if (cft->write_u64) {
+		unsigned long long v;
+		ret = kstrtoull(buf, 0, &v);
+		if (!ret)
+			ret = cft->write_u64(css, cft, v);
+	} else if (cft->write_s64) {
+		long long v;
+		ret = kstrtoll(buf, 0, &v);
+		if (!ret)
+			ret = cft->write_s64(css, cft, v);
+	} else {
+		ret = -EINVAL;
+	}
+
+	return ret ?: nbytes;
+}
+
+static __poll_t cgroup_file_poll(struct kernfs_open_file *of, poll_table *pt)
+{
+	struct cftype *cft = of_cft(of);
+
+	if (cft->poll)
+		return cft->poll(of, pt);
+
+	return kernfs_generic_poll(of, pt);
+}
+
+static void *cgroup_seqfile_start(struct seq_file *seq, loff_t *ppos)
+{
+	return seq_cft(seq)->seq_start(seq, ppos);
+}
+
+static void *cgroup_seqfile_next(struct seq_file *seq, void *v, loff_t *ppos)
+{
+	return seq_cft(seq)->seq_next(seq, v, ppos);
+}
+
+static void cgroup_seqfile_stop(struct seq_file *seq, void *v)
+{
+	if (seq_cft(seq)->seq_stop)
+		seq_cft(seq)->seq_stop(seq, v);
+}
+
+static int cgroup_seqfile_show(struct seq_file *m, void *arg)
+{
+	struct cftype *cft = seq_cft(m);
+	struct cgroup_subsys_state *css = seq_css(m);
+
+	if (cft->seq_show)
+		return cft->seq_show(m, arg);
+
+	if (cft->read_u64)
+		seq_printf(m, "%llu\n", cft->read_u64(css, cft));
+	else if (cft->read_s64)
+		seq_printf(m, "%lld\n", cft->read_s64(css, cft));
+	else
+		return -EINVAL;
+	return 0;
+}
+
+static struct kernfs_ops cgroup_kf_single_ops = {
+	.atomic_write_len	= PAGE_SIZE,
+	.open			= cgroup_file_open,
+	.release		= cgroup_file_release,
+	.write			= cgroup_file_write,
+	.poll			= cgroup_file_poll,
+	.seq_show		= cgroup_seqfile_show,
+};
+
+static struct kernfs_ops cgroup_kf_ops = {
+	.atomic_write_len	= PAGE_SIZE,
+	.open			= cgroup_file_open,
+	.release		= cgroup_file_release,
+	.write			= cgroup_file_write,
+	.poll			= cgroup_file_poll,
+	.seq_start		= cgroup_seqfile_start,
+	.seq_next		= cgroup_seqfile_next,
+	.seq_stop		= cgroup_seqfile_stop,
+	.seq_show		= cgroup_seqfile_show,
+};
+
+/* set uid and gid of cgroup dirs and files to that of the creator */
+static int cgroup_kn_set_ugid(struct kernfs_node *kn)
+{
+	struct iattr iattr = { .ia_valid = ATTR_UID | ATTR_GID,
+			       .ia_uid = current_fsuid(),
+			       .ia_gid = current_fsgid(), };
+
+	if (uid_eq(iattr.ia_uid, GLOBAL_ROOT_UID) &&
+	    gid_eq(iattr.ia_gid, GLOBAL_ROOT_GID))
+		return 0;
+
+	return kernfs_setattr(kn, &iattr);
+}
+
+static void cgroup_file_notify_timer(struct timer_list *timer)
+{
+	cgroup_file_notify(container_of(timer, struct cgroup_file,
+					notify_timer));
+}
+
+static int cgroup_add_file(struct cgroup_subsys_state *css, struct cgroup *cgrp,
+			   struct cftype *cft)
+{
+	char name[CGROUP_FILE_NAME_MAX];
+	struct kernfs_node *kn;
+	struct lock_class_key *key = NULL;
+	int ret;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	key = &cft->lockdep_key;
+#endif
+	kn = __kernfs_create_file(cgrp->kn, cgroup_file_name(cgrp, cft, name),
+				  cgroup_file_mode(cft),
+				  GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
+				  0, cft->kf_ops, cft,
+				  NULL, key);
+	if (IS_ERR(kn))
+		return PTR_ERR(kn);
+
+	ret = cgroup_kn_set_ugid(kn);
+	if (ret) {
+		kernfs_remove(kn);
+		return ret;
+	}
+
+	if (cft->file_offset) {
+		struct cgroup_file *cfile = (void *)css + cft->file_offset;
+
+		timer_setup(&cfile->notify_timer, cgroup_file_notify_timer, 0);
+
+		spin_lock_irq(&cgroup_file_kn_lock);
+		cfile->kn = kn;
+		spin_unlock_irq(&cgroup_file_kn_lock);
+	}
+
+	return 0;
+}
+
+/**
+ * cgroup_addrm_files - add or remove files to a cgroup directory
+ * @css: the target css
+ * @cgrp: the target cgroup (usually css->cgroup)
+ * @cfts: array of cftypes to be added
+ * @is_add: whether to add or remove
+ *
+ * Depending on @is_add, add or remove files defined by @cfts on @cgrp.
+ * For removals, this function never fails.
+ */
+static int cgroup_addrm_files(struct cgroup_subsys_state *css,
+			      struct cgroup *cgrp, struct cftype cfts[],
+			      bool is_add)
+{
+	struct cftype *cft, *cft_end = NULL;
+	int ret = 0;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+restart:
+	for (cft = cfts; cft != cft_end && cft->name[0] != '\0'; cft++) {
+		/* does cft->flags tell us to skip this file on @cgrp? */
+		if ((cft->flags & __CFTYPE_ONLY_ON_DFL) && !cgroup_on_dfl(cgrp))
+			continue;
+		if ((cft->flags & __CFTYPE_NOT_ON_DFL) && cgroup_on_dfl(cgrp))
+			continue;
+		if ((cft->flags & CFTYPE_NOT_ON_ROOT) && !cgroup_parent(cgrp))
+			continue;
+		if ((cft->flags & CFTYPE_ONLY_ON_ROOT) && cgroup_parent(cgrp))
+			continue;
+		if ((cft->flags & CFTYPE_DEBUG) && !cgroup_debug)
+			continue;
+		if (is_add) {
+			ret = cgroup_add_file(css, cgrp, cft);
+			if (ret) {
+				pr_warn("%s: failed to add %s, err=%d\n",
+					__func__, cft->name, ret);
+				cft_end = cft;
+				is_add = false;
+				goto restart;
+			}
+		} else {
+			cgroup_rm_file(cgrp, cft);
+		}
+	}
+	return ret;
+}
+
+static int cgroup_apply_cftypes(struct cftype *cfts, bool is_add)
+{
+	struct cgroup_subsys *ss = cfts[0].ss;
+	struct cgroup *root = &ss->root->cgrp;
+	struct cgroup_subsys_state *css;
+	int ret = 0;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	/* add/rm files for all cgroups created before */
+	css_for_each_descendant_pre(css, cgroup_css(root, ss)) {
+		struct cgroup *cgrp = css->cgroup;
+
+		if (!(css->flags & CSS_VISIBLE))
+			continue;
+
+		ret = cgroup_addrm_files(css, cgrp, cfts, is_add);
+		if (ret)
+			break;
+	}
+
+	if (is_add && !ret)
+		kernfs_activate(root->kn);
+	return ret;
+}
+
+static void cgroup_exit_cftypes(struct cftype *cfts)
+{
+	struct cftype *cft;
+
+	for (cft = cfts; cft->name[0] != '\0'; cft++) {
+		/* free copy for custom atomic_write_len, see init_cftypes() */
+		if (cft->max_write_len && cft->max_write_len != PAGE_SIZE)
+			kfree(cft->kf_ops);
+		cft->kf_ops = NULL;
+		cft->ss = NULL;
+
+		/* revert flags set by cgroup core while adding @cfts */
+		cft->flags &= ~(__CFTYPE_ONLY_ON_DFL | __CFTYPE_NOT_ON_DFL |
+				__CFTYPE_ADDED);
+	}
+}
+
+static int cgroup_init_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
+{
+	struct cftype *cft;
+	int ret = 0;
+
+	for (cft = cfts; cft->name[0] != '\0'; cft++) {
+		struct kernfs_ops *kf_ops;
+
+		WARN_ON(cft->ss || cft->kf_ops);
+
+		if (cft->flags & __CFTYPE_ADDED) {
+			ret = -EBUSY;
+			break;
+		}
+
+		if (cft->seq_start)
+			kf_ops = &cgroup_kf_ops;
+		else
+			kf_ops = &cgroup_kf_single_ops;
+
+		/*
+		 * Ugh... if @cft wants a custom max_write_len, we need to
+		 * make a copy of kf_ops to set its atomic_write_len.
+		 */
+		if (cft->max_write_len && cft->max_write_len != PAGE_SIZE) {
+			kf_ops = kmemdup(kf_ops, sizeof(*kf_ops), GFP_KERNEL);
+			if (!kf_ops) {
+				ret = -ENOMEM;
+				break;
+			}
+			kf_ops->atomic_write_len = cft->max_write_len;
+		}
+
+		cft->kf_ops = kf_ops;
+		cft->ss = ss;
+		cft->flags |= __CFTYPE_ADDED;
+	}
+
+	if (ret)
+		cgroup_exit_cftypes(cfts);
+	return ret;
+}
+
+static int cgroup_rm_cftypes_locked(struct cftype *cfts)
+{
+	lockdep_assert_held(&cgroup_mutex);
+
+	list_del(&cfts->node);
+	cgroup_apply_cftypes(cfts, false);
+	cgroup_exit_cftypes(cfts);
+	return 0;
+}
+
+/**
+ * cgroup_rm_cftypes - remove an array of cftypes from a subsystem
+ * @cfts: zero-length name terminated array of cftypes
+ *
+ * Unregister @cfts.  Files described by @cfts are removed from all
+ * existing cgroups and all future cgroups won't have them either.  This
+ * function can be called anytime whether @cfts' subsys is attached or not.
+ *
+ * Returns 0 on successful unregistration, -ENOENT if @cfts is not
+ * registered.
+ */
+int cgroup_rm_cftypes(struct cftype *cfts)
+{
+	int ret;
+
+	if (!cfts || cfts[0].name[0] == '\0')
+		return 0;
+
+	if (!(cfts[0].flags & __CFTYPE_ADDED))
+		return -ENOENT;
+
+	cgroup_lock();
+	ret = cgroup_rm_cftypes_locked(cfts);
+	cgroup_unlock();
+	return ret;
+}
+
+/**
+ * cgroup_add_cftypes - add an array of cftypes to a subsystem
+ * @ss: target cgroup subsystem
+ * @cfts: zero-length name terminated array of cftypes
+ *
+ * Register @cfts to @ss.  Files described by @cfts are created for all
+ * existing cgroups to which @ss is attached and all future cgroups will
+ * have them too.  This function can be called anytime whether @ss is
+ * attached or not.
+ *
+ * Returns 0 on successful registration, -errno on failure.  Note that this
+ * function currently returns 0 as long as @cfts registration is successful
+ * even if some file creation attempts on existing cgroups fail.
+ */
+static int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
+{
+	int ret;
+
+	if (!cgroup_ssid_enabled(ss->id))
+		return 0;
+
+	if (!cfts || cfts[0].name[0] == '\0')
+		return 0;
+
+	ret = cgroup_init_cftypes(ss, cfts);
+	if (ret)
+		return ret;
+
+	cgroup_lock();
+
+	list_add_tail(&cfts->node, &ss->cfts);
+	ret = cgroup_apply_cftypes(cfts, true);
+	if (ret)
+		cgroup_rm_cftypes_locked(cfts);
+
+	cgroup_unlock();
+	return ret;
+}
+
+/**
+ * cgroup_add_dfl_cftypes - add an array of cftypes for default hierarchy
+ * @ss: target cgroup subsystem
+ * @cfts: zero-length name terminated array of cftypes
+ *
+ * Similar to cgroup_add_cftypes() but the added files are only used for
+ * the default hierarchy.
+ */
+int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
+{
+	struct cftype *cft;
+
+	for (cft = cfts; cft && cft->name[0] != '\0'; cft++)
+		cft->flags |= __CFTYPE_ONLY_ON_DFL;
+	return cgroup_add_cftypes(ss, cfts);
+}
+
+/**
+ * cgroup_add_legacy_cftypes - add an array of cftypes for legacy hierarchies
+ * @ss: target cgroup subsystem
+ * @cfts: zero-length name terminated array of cftypes
+ *
+ * Similar to cgroup_add_cftypes() but the added files are only used for
+ * the legacy hierarchies.
+ */
+int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
+{
+	struct cftype *cft;
+
+	for (cft = cfts; cft && cft->name[0] != '\0'; cft++)
+		cft->flags |= __CFTYPE_NOT_ON_DFL;
+	return cgroup_add_cftypes(ss, cfts);
+}
+
+/**
+ * cgroup_file_notify - generate a file modified event for a cgroup_file
+ * @cfile: target cgroup_file
+ *
+ * @cfile must have been obtained by setting cftype->file_offset.
+ */
+void cgroup_file_notify(struct cgroup_file *cfile)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&cgroup_file_kn_lock, flags);
+	if (cfile->kn) {
+		unsigned long last = cfile->notified_at;
+		unsigned long next = last + CGROUP_FILE_NOTIFY_MIN_INTV;
+
+		if (time_in_range(jiffies, last, next)) {
+			timer_reduce(&cfile->notify_timer, next);
+		} else {
+			kernfs_notify(cfile->kn);
+			cfile->notified_at = jiffies;
+		}
+	}
+	spin_unlock_irqrestore(&cgroup_file_kn_lock, flags);
+}
+
+/**
+ * cgroup_file_show - show or hide a hidden cgroup file
+ * @cfile: target cgroup_file obtained by setting cftype->file_offset
+ * @show: whether to show or hide
+ */
+void cgroup_file_show(struct cgroup_file *cfile, bool show)
+{
+	struct kernfs_node *kn;
+
+	spin_lock_irq(&cgroup_file_kn_lock);
+	kn = cfile->kn;
+	kernfs_get(kn);
+	spin_unlock_irq(&cgroup_file_kn_lock);
+
+	if (kn)
+		kernfs_show(kn, show);
+
+	kernfs_put(kn);
+}
+
+/**
+ * css_next_child - find the next child of a given css
+ * @pos: the current position (%NULL to initiate traversal)
+ * @parent: css whose children to walk
+ *
+ * This function returns the next child of @parent and should be called
+ * under either cgroup_mutex or RCU read lock.  The only requirement is
+ * that @parent and @pos are accessible.  The next sibling is guaranteed to
+ * be returned regardless of their states.
+ *
+ * If a subsystem synchronizes ->css_online() and the start of iteration, a
+ * css which finished ->css_online() is guaranteed to be visible in the
+ * future iterations and will stay visible until the last reference is put.
+ * A css which hasn't finished ->css_online() or already finished
+ * ->css_offline() may show up during traversal.  It's each subsystem's
+ * responsibility to synchronize against on/offlining.
+ */
+struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
+					   struct cgroup_subsys_state *parent)
+{
+	struct cgroup_subsys_state *next;
+
+	cgroup_assert_mutex_or_rcu_locked();
+
+	/*
+	 * @pos could already have been unlinked from the sibling list.
+	 * Once a cgroup is removed, its ->sibling.next is no longer
+	 * updated when its next sibling changes.  CSS_RELEASED is set when
+	 * @pos is taken off list, at which time its next pointer is valid,
+	 * and, as releases are serialized, the one pointed to by the next
+	 * pointer is guaranteed to not have started release yet.  This
+	 * implies that if we observe !CSS_RELEASED on @pos in this RCU
+	 * critical section, the one pointed to by its next pointer is
+	 * guaranteed to not have finished its RCU grace period even if we
+	 * have dropped rcu_read_lock() in-between iterations.
+	 *
+	 * If @pos has CSS_RELEASED set, its next pointer can't be
+	 * dereferenced; however, as each css is given a monotonically
+	 * increasing unique serial number and always appended to the
+	 * sibling list, the next one can be found by walking the parent's
+	 * children until the first css with higher serial number than
+	 * @pos's.  While this path can be slower, it happens iff iteration
+	 * races against release and the race window is very small.
+	 */
+	if (!pos) {
+		next = list_entry_rcu(parent->children.next, struct cgroup_subsys_state, sibling);
+	} else if (likely(!(pos->flags & CSS_RELEASED))) {
+		next = list_entry_rcu(pos->sibling.next, struct cgroup_subsys_state, sibling);
+	} else {
+		list_for_each_entry_rcu(next, &parent->children, sibling,
+					lockdep_is_held(&cgroup_mutex))
+			if (next->serial_nr > pos->serial_nr)
+				break;
+	}
+
+	/*
+	 * @next, if not pointing to the head, can be dereferenced and is
+	 * the next sibling.
+	 */
+	if (&next->sibling != &parent->children)
+		return next;
+	return NULL;
+}
+
+/**
+ * css_next_descendant_pre - find the next descendant for pre-order walk
+ * @pos: the current position (%NULL to initiate traversal)
+ * @root: css whose descendants to walk
+ *
+ * To be used by css_for_each_descendant_pre().  Find the next descendant
+ * to visit for pre-order traversal of @root's descendants.  @root is
+ * included in the iteration and the first node to be visited.
+ *
+ * While this function requires cgroup_mutex or RCU read locking, it
+ * doesn't require the whole traversal to be contained in a single critical
+ * section.  This function will return the correct next descendant as long
+ * as both @pos and @root are accessible and @pos is a descendant of @root.
+ *
+ * If a subsystem synchronizes ->css_online() and the start of iteration, a
+ * css which finished ->css_online() is guaranteed to be visible in the
+ * future iterations and will stay visible until the last reference is put.
+ * A css which hasn't finished ->css_online() or already finished
+ * ->css_offline() may show up during traversal.  It's each subsystem's
+ * responsibility to synchronize against on/offlining.
+ */
+struct cgroup_subsys_state *
+css_next_descendant_pre(struct cgroup_subsys_state *pos,
+			struct cgroup_subsys_state *root)
+{
+	struct cgroup_subsys_state *next;
+
+	cgroup_assert_mutex_or_rcu_locked();
+
+	/* if first iteration, visit @root */
+	if (!pos)
+		return root;
+
+	/* visit the first child if exists */
+	next = css_next_child(NULL, pos);
+	if (next)
+		return next;
+
+	/* no child, visit my or the closest ancestor's next sibling */
+	while (pos != root) {
+		next = css_next_child(pos, pos->parent);
+		if (next)
+			return next;
+		pos = pos->parent;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(css_next_descendant_pre);
+
+/**
+ * css_rightmost_descendant - return the rightmost descendant of a css
+ * @pos: css of interest
+ *
+ * Return the rightmost descendant of @pos.  If there's no descendant, @pos
+ * is returned.  This can be used during pre-order traversal to skip
+ * subtree of @pos.
+ *
+ * While this function requires cgroup_mutex or RCU read locking, it
+ * doesn't require the whole traversal to be contained in a single critical
+ * section.  This function will return the correct rightmost descendant as
+ * long as @pos is accessible.
+ */
+struct cgroup_subsys_state *
+css_rightmost_descendant(struct cgroup_subsys_state *pos)
+{
+	struct cgroup_subsys_state *last, *tmp;
+
+	cgroup_assert_mutex_or_rcu_locked();
+
+	do {
+		last = pos;
+		/* ->prev isn't RCU safe, walk ->next till the end */
+		pos = NULL;
+		css_for_each_child(tmp, last)
+			pos = tmp;
+	} while (pos);
+
+	return last;
+}
+
+static struct cgroup_subsys_state *
+css_leftmost_descendant(struct cgroup_subsys_state *pos)
+{
+	struct cgroup_subsys_state *last;
+
+	do {
+		last = pos;
+		pos = css_next_child(NULL, pos);
+	} while (pos);
+
+	return last;
+}
+
+/**
+ * css_next_descendant_post - find the next descendant for post-order walk
+ * @pos: the current position (%NULL to initiate traversal)
+ * @root: css whose descendants to walk
+ *
+ * To be used by css_for_each_descendant_post().  Find the next descendant
+ * to visit for post-order traversal of @root's descendants.  @root is
+ * included in the iteration and the last node to be visited.
+ *
+ * While this function requires cgroup_mutex or RCU read locking, it
+ * doesn't require the whole traversal to be contained in a single critical
+ * section.  This function will return the correct next descendant as long
+ * as both @pos and @cgroup are accessible and @pos is a descendant of
+ * @cgroup.
+ *
+ * If a subsystem synchronizes ->css_online() and the start of iteration, a
+ * css which finished ->css_online() is guaranteed to be visible in the
+ * future iterations and will stay visible until the last reference is put.
+ * A css which hasn't finished ->css_online() or already finished
+ * ->css_offline() may show up during traversal.  It's each subsystem's
+ * responsibility to synchronize against on/offlining.
+ */
+struct cgroup_subsys_state *
+css_next_descendant_post(struct cgroup_subsys_state *pos,
+			 struct cgroup_subsys_state *root)
+{
+	struct cgroup_subsys_state *next;
+
+	cgroup_assert_mutex_or_rcu_locked();
+
+	/* if first iteration, visit leftmost descendant which may be @root */
+	if (!pos)
+		return css_leftmost_descendant(root);
+
+	/* if we visited @root, we're done */
+	if (pos == root)
+		return NULL;
+
+	/* if there's an unvisited sibling, visit its leftmost descendant */
+	next = css_next_child(pos, pos->parent);
+	if (next)
+		return css_leftmost_descendant(next);
+
+	/* no sibling left, visit parent */
+	return pos->parent;
+}
+
+/**
+ * css_has_online_children - does a css have online children
+ * @css: the target css
+ *
+ * Returns %true if @css has any online children; otherwise, %false.  This
+ * function can be called from any context but the caller is responsible
+ * for synchronizing against on/offlining as necessary.
+ */
+bool css_has_online_children(struct cgroup_subsys_state *css)
+{
+	struct cgroup_subsys_state *child;
+	bool ret = false;
+
+	rcu_read_lock();
+	css_for_each_child(child, css) {
+		if (child->flags & CSS_ONLINE) {
+			ret = true;
+			break;
+		}
+	}
+	rcu_read_unlock();
+	return ret;
+}
+
+static struct css_set *css_task_iter_next_css_set(struct css_task_iter *it)
+{
+	struct list_head *l;
+	struct cgrp_cset_link *link;
+	struct css_set *cset;
+
+	lockdep_assert_held(&css_set_lock);
+
+	/* find the next threaded cset */
+	if (it->tcset_pos) {
+		l = it->tcset_pos->next;
+
+		if (l != it->tcset_head) {
+			it->tcset_pos = l;
+			return container_of(l, struct css_set,
+					    threaded_csets_node);
+		}
+
+		it->tcset_pos = NULL;
+	}
+
+	/* find the next cset */
+	l = it->cset_pos;
+	l = l->next;
+	if (l == it->cset_head) {
+		it->cset_pos = NULL;
+		return NULL;
+	}
+
+	if (it->ss) {
+		cset = container_of(l, struct css_set, e_cset_node[it->ss->id]);
+	} else {
+		link = list_entry(l, struct cgrp_cset_link, cset_link);
+		cset = link->cset;
+	}
+
+	it->cset_pos = l;
+
+	/* initialize threaded css_set walking */
+	if (it->flags & CSS_TASK_ITER_THREADED) {
+		if (it->cur_dcset)
+			put_css_set_locked(it->cur_dcset);
+		it->cur_dcset = cset;
+		get_css_set(cset);
+
+		it->tcset_head = &cset->threaded_csets;
+		it->tcset_pos = &cset->threaded_csets;
+	}
+
+	return cset;
+}
+
+/**
+ * css_task_iter_advance_css_set - advance a task iterator to the next css_set
+ * @it: the iterator to advance
+ *
+ * Advance @it to the next css_set to walk.
+ */
+static void css_task_iter_advance_css_set(struct css_task_iter *it)
+{
+	struct css_set *cset;
+
+	lockdep_assert_held(&css_set_lock);
+
+	/* Advance to the next non-empty css_set and find first non-empty tasks list*/
+	while ((cset = css_task_iter_next_css_set(it))) {
+		if (!list_empty(&cset->tasks)) {
+			it->cur_tasks_head = &cset->tasks;
+			break;
+		} else if (!list_empty(&cset->mg_tasks)) {
+			it->cur_tasks_head = &cset->mg_tasks;
+			break;
+		} else if (!list_empty(&cset->dying_tasks)) {
+			it->cur_tasks_head = &cset->dying_tasks;
+			break;
+		}
+	}
+	if (!cset) {
+		it->task_pos = NULL;
+		return;
+	}
+	it->task_pos = it->cur_tasks_head->next;
+
+	/*
+	 * We don't keep css_sets locked across iteration steps and thus
+	 * need to take steps to ensure that iteration can be resumed after
+	 * the lock is re-acquired.  Iteration is performed at two levels -
+	 * css_sets and tasks in them.
+	 *
+	 * Once created, a css_set never leaves its cgroup lists, so a
+	 * pinned css_set is guaranteed to stay put and we can resume
+	 * iteration afterwards.
+	 *
+	 * Tasks may leave @cset across iteration steps.  This is resolved
+	 * by registering each iterator with the css_set currently being
+	 * walked and making css_set_move_task() advance iterators whose
+	 * next task is leaving.
+	 */
+	if (it->cur_cset) {
+		list_del(&it->iters_node);
+		put_css_set_locked(it->cur_cset);
+	}
+	get_css_set(cset);
+	it->cur_cset = cset;
+	list_add(&it->iters_node, &cset->task_iters);
+}
+
+static void css_task_iter_skip(struct css_task_iter *it,
+			       struct task_struct *task)
+{
+	lockdep_assert_held(&css_set_lock);
+
+	if (it->task_pos == &task->cg_list) {
+		it->task_pos = it->task_pos->next;
+		it->flags |= CSS_TASK_ITER_SKIPPED;
+	}
+}
+
+static void css_task_iter_advance(struct css_task_iter *it)
+{
+	struct task_struct *task;
+
+	lockdep_assert_held(&css_set_lock);
+repeat:
+	if (it->task_pos) {
+		/*
+		 * Advance iterator to find next entry. We go through cset
+		 * tasks, mg_tasks and dying_tasks, when consumed we move onto
+		 * the next cset.
+		 */
+		if (it->flags & CSS_TASK_ITER_SKIPPED)
+			it->flags &= ~CSS_TASK_ITER_SKIPPED;
+		else
+			it->task_pos = it->task_pos->next;
+
+		if (it->task_pos == &it->cur_cset->tasks) {
+			it->cur_tasks_head = &it->cur_cset->mg_tasks;
+			it->task_pos = it->cur_tasks_head->next;
+		}
+		if (it->task_pos == &it->cur_cset->mg_tasks) {
+			it->cur_tasks_head = &it->cur_cset->dying_tasks;
+			it->task_pos = it->cur_tasks_head->next;
+		}
+		if (it->task_pos == &it->cur_cset->dying_tasks)
+			css_task_iter_advance_css_set(it);
+	} else {
+		/* called from start, proceed to the first cset */
+		css_task_iter_advance_css_set(it);
+	}
+
+	if (!it->task_pos)
+		return;
+
+	task = list_entry(it->task_pos, struct task_struct, cg_list);
+
+	if (it->flags & CSS_TASK_ITER_PROCS) {
+		/* if PROCS, skip over tasks which aren't group leaders */
+		if (!thread_group_leader(task))
+			goto repeat;
+
+		/* and dying leaders w/o live member threads */
+		if (it->cur_tasks_head == &it->cur_cset->dying_tasks &&
+		    !atomic_read(&task->signal->live))
+			goto repeat;
+	} else {
+		/* skip all dying ones */
+		if (it->cur_tasks_head == &it->cur_cset->dying_tasks)
+			goto repeat;
+	}
+}
+
+/**
+ * css_task_iter_start - initiate task iteration
+ * @css: the css to walk tasks of
+ * @flags: CSS_TASK_ITER_* flags
+ * @it: the task iterator to use
+ *
+ * Initiate iteration through the tasks of @css.  The caller can call
+ * css_task_iter_next() to walk through the tasks until the function
+ * returns NULL.  On completion of iteration, css_task_iter_end() must be
+ * called.
+ */
+void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
+			 struct css_task_iter *it)
+{
+	memset(it, 0, sizeof(*it));
+
+	spin_lock_irq(&css_set_lock);
+
+	it->ss = css->ss;
+	it->flags = flags;
+
+	if (CGROUP_HAS_SUBSYS_CONFIG && it->ss)
+		it->cset_pos = &css->cgroup->e_csets[css->ss->id];
+	else
+		it->cset_pos = &css->cgroup->cset_links;
+
+	it->cset_head = it->cset_pos;
+
+	css_task_iter_advance(it);
+
+	spin_unlock_irq(&css_set_lock);
+}
+
+/**
+ * css_task_iter_next - return the next task for the iterator
+ * @it: the task iterator being iterated
+ *
+ * The "next" function for task iteration.  @it should have been
+ * initialized via css_task_iter_start().  Returns NULL when the iteration
+ * reaches the end.
+ */
+struct task_struct *css_task_iter_next(struct css_task_iter *it)
+{
+	if (it->cur_task) {
+		put_task_struct(it->cur_task);
+		it->cur_task = NULL;
+	}
+
+	spin_lock_irq(&css_set_lock);
+
+	/* @it may be half-advanced by skips, finish advancing */
+	if (it->flags & CSS_TASK_ITER_SKIPPED)
+		css_task_iter_advance(it);
+
+	if (it->task_pos) {
+		it->cur_task = list_entry(it->task_pos, struct task_struct,
+					  cg_list);
+		get_task_struct(it->cur_task);
+		css_task_iter_advance(it);
+	}
+
+	spin_unlock_irq(&css_set_lock);
+
+	return it->cur_task;
+}
+
+/**
+ * css_task_iter_end - finish task iteration
+ * @it: the task iterator to finish
+ *
+ * Finish task iteration started by css_task_iter_start().
+ */
+void css_task_iter_end(struct css_task_iter *it)
+{
+	if (it->cur_cset) {
+		spin_lock_irq(&css_set_lock);
+		list_del(&it->iters_node);
+		put_css_set_locked(it->cur_cset);
+		spin_unlock_irq(&css_set_lock);
+	}
+
+	if (it->cur_dcset)
+		put_css_set(it->cur_dcset);
+
+	if (it->cur_task)
+		put_task_struct(it->cur_task);
+}
+
+static void cgroup_procs_release(struct kernfs_open_file *of)
+{
+	struct cgroup_file_ctx *ctx = of->priv;
+
+	if (ctx->procs.started)
+		css_task_iter_end(&ctx->procs.iter);
+}
+
+static void *cgroup_procs_next(struct seq_file *s, void *v, loff_t *pos)
+{
+	struct kernfs_open_file *of = s->private;
+	struct cgroup_file_ctx *ctx = of->priv;
+
+	if (pos)
+		(*pos)++;
+
+	return css_task_iter_next(&ctx->procs.iter);
+}
+
+static void *__cgroup_procs_start(struct seq_file *s, loff_t *pos,
+				  unsigned int iter_flags)
+{
+	struct kernfs_open_file *of = s->private;
+	struct cgroup *cgrp = seq_css(s)->cgroup;
+	struct cgroup_file_ctx *ctx = of->priv;
+	struct css_task_iter *it = &ctx->procs.iter;
+
+	/*
+	 * When a seq_file is seeked, it's always traversed sequentially
+	 * from position 0, so we can simply keep iterating on !0 *pos.
+	 */
+	if (!ctx->procs.started) {
+		if (WARN_ON_ONCE((*pos)))
+			return ERR_PTR(-EINVAL);
+		css_task_iter_start(&cgrp->self, iter_flags, it);
+		ctx->procs.started = true;
+	} else if (!(*pos)) {
+		css_task_iter_end(it);
+		css_task_iter_start(&cgrp->self, iter_flags, it);
+	} else
+		return it->cur_task;
+
+	return cgroup_procs_next(s, NULL, NULL);
+}
+
+static void *cgroup_procs_start(struct seq_file *s, loff_t *pos)
+{
+	struct cgroup *cgrp = seq_css(s)->cgroup;
+
+	/*
+	 * All processes of a threaded subtree belong to the domain cgroup
+	 * of the subtree.  Only threads can be distributed across the
+	 * subtree.  Reject reads on cgroup.procs in the subtree proper.
+	 * They're always empty anyway.
+	 */
+	if (cgroup_is_threaded(cgrp))
+		return ERR_PTR(-EOPNOTSUPP);
+
+	return __cgroup_procs_start(s, pos, CSS_TASK_ITER_PROCS |
+					    CSS_TASK_ITER_THREADED);
+}
+
+static int cgroup_procs_show(struct seq_file *s, void *v)
+{
+	seq_printf(s, "%d\n", task_pid_vnr(v));
+	return 0;
+}
+
+static int cgroup_may_write(const struct cgroup *cgrp, struct super_block *sb)
+{
+	int ret;
+	struct inode *inode;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	inode = kernfs_get_inode(sb, cgrp->procs_file.kn);
+	if (!inode)
+		return -ENOMEM;
+
+	ret = inode_permission(&init_user_ns, inode, MAY_WRITE);
+	iput(inode);
+	return ret;
+}
+
+static int cgroup_procs_write_permission(struct cgroup *src_cgrp,
+					 struct cgroup *dst_cgrp,
+					 struct super_block *sb,
+					 struct cgroup_namespace *ns)
+{
+	struct cgroup *com_cgrp = src_cgrp;
+	int ret;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	/* find the common ancestor */
+	while (!cgroup_is_descendant(dst_cgrp, com_cgrp))
+		com_cgrp = cgroup_parent(com_cgrp);
+
+	/* %current should be authorized to migrate to the common ancestor */
+	ret = cgroup_may_write(com_cgrp, sb);
+	if (ret)
+		return ret;
+
+	/*
+	 * If namespaces are delegation boundaries, %current must be able
+	 * to see both source and destination cgroups from its namespace.
+	 */
+	if ((cgrp_dfl_root.flags & CGRP_ROOT_NS_DELEGATE) &&
+	    (!cgroup_is_descendant(src_cgrp, ns->root_cset->dfl_cgrp) ||
+	     !cgroup_is_descendant(dst_cgrp, ns->root_cset->dfl_cgrp)))
+		return -ENOENT;
+
+	return 0;
+}
+
+static int cgroup_attach_permissions(struct cgroup *src_cgrp,
+				     struct cgroup *dst_cgrp,
+				     struct super_block *sb, bool threadgroup,
+				     struct cgroup_namespace *ns)
+{
+	int ret = 0;
+
+	ret = cgroup_procs_write_permission(src_cgrp, dst_cgrp, sb, ns);
+	if (ret)
+		return ret;
+
+	ret = cgroup_migrate_vet_dst(dst_cgrp);
+	if (ret)
+		return ret;
+
+	if (!threadgroup && (src_cgrp->dom_cgrp != dst_cgrp->dom_cgrp))
+		ret = -EOPNOTSUPP;
+
+	return ret;
+}
+
+static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
+				    bool threadgroup)
+{
+	struct cgroup_file_ctx *ctx = of->priv;
+	struct cgroup *src_cgrp, *dst_cgrp;
+	struct task_struct *task;
+	const struct cred *saved_cred;
+	ssize_t ret;
+	bool threadgroup_locked;
+
+	dst_cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!dst_cgrp)
+		return -ENODEV;
+
+	task = cgroup_procs_write_start(buf, threadgroup, &threadgroup_locked);
+	ret = PTR_ERR_OR_ZERO(task);
+	if (ret)
+		goto out_unlock;
+
+	/* find the source cgroup */
+	spin_lock_irq(&css_set_lock);
+	src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root);
+	spin_unlock_irq(&css_set_lock);
+
+	/*
+	 * Process and thread migrations follow same delegation rule. Check
+	 * permissions using the credentials from file open to protect against
+	 * inherited fd attacks.
+	 */
+	saved_cred = override_creds(of->file->f_cred);
+	ret = cgroup_attach_permissions(src_cgrp, dst_cgrp,
+					of->file->f_path.dentry->d_sb,
+					threadgroup, ctx->ns);
+	revert_creds(saved_cred);
+	if (ret)
+		goto out_finish;
+
+	ret = cgroup_attach_task(dst_cgrp, task, threadgroup);
+
+out_finish:
+	cgroup_procs_write_finish(task, threadgroup_locked);
+out_unlock:
+	cgroup_kn_unlock(of->kn);
+
+	return ret;
+}
+
+static ssize_t cgroup_procs_write(struct kernfs_open_file *of,
+				  char *buf, size_t nbytes, loff_t off)
+{
+	return __cgroup_procs_write(of, buf, true) ?: nbytes;
+}
+
+static void *cgroup_threads_start(struct seq_file *s, loff_t *pos)
+{
+	return __cgroup_procs_start(s, pos, 0);
+}
+
+static ssize_t cgroup_threads_write(struct kernfs_open_file *of,
+				    char *buf, size_t nbytes, loff_t off)
+{
+	return __cgroup_procs_write(of, buf, false) ?: nbytes;
+}
+
+/* cgroup core interface files for the default hierarchy */
+static struct cftype cgroup_base_files[] = {
+	{
+		.name = "cgroup.type",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cgroup_type_show,
+		.write = cgroup_type_write,
+	},
+	{
+		.name = "cgroup.procs",
+		.flags = CFTYPE_NS_DELEGATABLE,
+		.file_offset = offsetof(struct cgroup, procs_file),
+		.release = cgroup_procs_release,
+		.seq_start = cgroup_procs_start,
+		.seq_next = cgroup_procs_next,
+		.seq_show = cgroup_procs_show,
+		.write = cgroup_procs_write,
+	},
+	{
+		.name = "cgroup.threads",
+		.flags = CFTYPE_NS_DELEGATABLE,
+		.release = cgroup_procs_release,
+		.seq_start = cgroup_threads_start,
+		.seq_next = cgroup_procs_next,
+		.seq_show = cgroup_procs_show,
+		.write = cgroup_threads_write,
+	},
+	{
+		.name = "cgroup.controllers",
+		.seq_show = cgroup_controllers_show,
+	},
+	{
+		.name = "cgroup.subtree_control",
+		.flags = CFTYPE_NS_DELEGATABLE,
+		.seq_show = cgroup_subtree_control_show,
+		.write = cgroup_subtree_control_write,
+	},
+	{
+		.name = "cgroup.events",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.file_offset = offsetof(struct cgroup, events_file),
+		.seq_show = cgroup_events_show,
+	},
+	{
+		.name = "cgroup.max.descendants",
+		.seq_show = cgroup_max_descendants_show,
+		.write = cgroup_max_descendants_write,
+	},
+	{
+		.name = "cgroup.max.depth",
+		.seq_show = cgroup_max_depth_show,
+		.write = cgroup_max_depth_write,
+	},
+	{
+		.name = "cgroup.stat",
+		.seq_show = cgroup_stat_show,
+	},
+	{
+		.name = "cgroup.freeze",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cgroup_freeze_show,
+		.write = cgroup_freeze_write,
+	},
+	{
+		.name = "cgroup.kill",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.write = cgroup_kill_write,
+	},
+	{
+		.name = "cpu.stat",
+		.seq_show = cpu_stat_show,
+	},
+	{ }	/* terminate */
+};
+
+static struct cftype cgroup_psi_files[] = {
+#ifdef CONFIG_PSI
+	{
+		.name = "io.pressure",
+		.file_offset = offsetof(struct cgroup, psi_files[PSI_IO]),
+		.seq_show = cgroup_io_pressure_show,
+		.write = cgroup_io_pressure_write,
+		.poll = cgroup_pressure_poll,
+		.release = cgroup_pressure_release,
+	},
+	{
+		.name = "memory.pressure",
+		.file_offset = offsetof(struct cgroup, psi_files[PSI_MEM]),
+		.seq_show = cgroup_memory_pressure_show,
+		.write = cgroup_memory_pressure_write,
+		.poll = cgroup_pressure_poll,
+		.release = cgroup_pressure_release,
+	},
+	{
+		.name = "cpu.pressure",
+		.file_offset = offsetof(struct cgroup, psi_files[PSI_CPU]),
+		.seq_show = cgroup_cpu_pressure_show,
+		.write = cgroup_cpu_pressure_write,
+		.poll = cgroup_pressure_poll,
+		.release = cgroup_pressure_release,
+	},
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	{
+		.name = "irq.pressure",
+		.file_offset = offsetof(struct cgroup, psi_files[PSI_IRQ]),
+		.seq_show = cgroup_irq_pressure_show,
+		.write = cgroup_irq_pressure_write,
+		.poll = cgroup_pressure_poll,
+		.release = cgroup_pressure_release,
+	},
+#endif
+	{
+		.name = "cgroup.pressure",
+		.seq_show = cgroup_pressure_show,
+		.write = cgroup_pressure_write,
+	},
+#endif /* CONFIG_PSI */
+	{ }	/* terminate */
+};
+
+/*
+ * css destruction is four-stage process.
+ *
+ * 1. Destruction starts.  Killing of the percpu_ref is initiated.
+ *    Implemented in kill_css().
+ *
+ * 2. When the percpu_ref is confirmed to be visible as killed on all CPUs
+ *    and thus css_tryget_online() is guaranteed to fail, the css can be
+ *    offlined by invoking offline_css().  After offlining, the base ref is
+ *    put.  Implemented in css_killed_work_fn().
+ *
+ * 3. When the percpu_ref reaches zero, the only possible remaining
+ *    accessors are inside RCU read sections.  css_release() schedules the
+ *    RCU callback.
+ *
+ * 4. After the grace period, the css can be freed.  Implemented in
+ *    css_free_work_fn().
+ *
+ * It is actually hairier because both step 2 and 4 require process context
+ * and thus involve punting to css->destroy_work adding two additional
+ * steps to the already complex sequence.
+ */
+static void css_free_rwork_fn(struct work_struct *work)
+{
+	struct cgroup_subsys_state *css = container_of(to_rcu_work(work),
+				struct cgroup_subsys_state, destroy_rwork);
+	struct cgroup_subsys *ss = css->ss;
+	struct cgroup *cgrp = css->cgroup;
+
+	percpu_ref_exit(&css->refcnt);
+
+	if (ss) {
+		/* css free path */
+		struct cgroup_subsys_state *parent = css->parent;
+		int id = css->id;
+
+		ss->css_free(css);
+		cgroup_idr_remove(&ss->css_idr, id);
+		cgroup_put(cgrp);
+
+		if (parent)
+			css_put(parent);
+	} else {
+		/* cgroup free path */
+		atomic_dec(&cgrp->root->nr_cgrps);
+		cgroup1_pidlist_destroy_all(cgrp);
+		cancel_work_sync(&cgrp->release_agent_work);
+
+		if (cgroup_parent(cgrp)) {
+			/*
+			 * We get a ref to the parent, and put the ref when
+			 * this cgroup is being freed, so it's guaranteed
+			 * that the parent won't be destroyed before its
+			 * children.
+			 */
+			cgroup_put(cgroup_parent(cgrp));
+			kernfs_put(cgrp->kn);
+			psi_cgroup_free(cgrp);
+			cgroup_rstat_exit(cgrp);
+			kfree(cgrp);
+		} else {
+			/*
+			 * This is root cgroup's refcnt reaching zero,
+			 * which indicates that the root should be
+			 * released.
+			 */
+			cgroup_destroy_root(cgrp->root);
+		}
+	}
+}
+
+static void css_release_work_fn(struct work_struct *work)
+{
+	struct cgroup_subsys_state *css =
+		container_of(work, struct cgroup_subsys_state, destroy_work);
+	struct cgroup_subsys *ss = css->ss;
+	struct cgroup *cgrp = css->cgroup;
+
+	cgroup_lock();
+
+	css->flags |= CSS_RELEASED;
+	list_del_rcu(&css->sibling);
+
+	if (ss) {
+		/* css release path */
+		if (!list_empty(&css->rstat_css_node)) {
+			cgroup_rstat_flush(cgrp);
+			list_del_rcu(&css->rstat_css_node);
+		}
+
+		cgroup_idr_replace(&ss->css_idr, NULL, css->id);
+		if (ss->css_released)
+			ss->css_released(css);
+	} else {
+		struct cgroup *tcgrp;
+
+		/* cgroup release path */
+		TRACE_CGROUP_PATH(release, cgrp);
+
+		cgroup_rstat_flush(cgrp);
+
+		spin_lock_irq(&css_set_lock);
+		for (tcgrp = cgroup_parent(cgrp); tcgrp;
+		     tcgrp = cgroup_parent(tcgrp))
+			tcgrp->nr_dying_descendants--;
+		spin_unlock_irq(&css_set_lock);
+
+		/*
+		 * There are two control paths which try to determine
+		 * cgroup from dentry without going through kernfs -
+		 * cgroupstats_build() and css_tryget_online_from_dir().
+		 * Those are supported by RCU protecting clearing of
+		 * cgrp->kn->priv backpointer.
+		 */
+		if (cgrp->kn)
+			RCU_INIT_POINTER(*(void __rcu __force **)&cgrp->kn->priv,
+					 NULL);
+	}
+
+	cgroup_unlock();
+
+	INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
+	queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
+}
+
+static void css_release(struct percpu_ref *ref)
+{
+	struct cgroup_subsys_state *css =
+		container_of(ref, struct cgroup_subsys_state, refcnt);
+
+	INIT_WORK(&css->destroy_work, css_release_work_fn);
+	queue_work(cgroup_destroy_wq, &css->destroy_work);
+}
+
+static void init_and_link_css(struct cgroup_subsys_state *css,
+			      struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+	lockdep_assert_held(&cgroup_mutex);
+
+	cgroup_get_live(cgrp);
+
+	memset(css, 0, sizeof(*css));
+	css->cgroup = cgrp;
+	css->ss = ss;
+	css->id = -1;
+	INIT_LIST_HEAD(&css->sibling);
+	INIT_LIST_HEAD(&css->children);
+	INIT_LIST_HEAD(&css->rstat_css_node);
+	css->serial_nr = css_serial_nr_next++;
+	atomic_set(&css->online_cnt, 0);
+
+	if (cgroup_parent(cgrp)) {
+		css->parent = cgroup_css(cgroup_parent(cgrp), ss);
+		css_get(css->parent);
+	}
+
+	if (ss->css_rstat_flush)
+		list_add_rcu(&css->rstat_css_node, &cgrp->rstat_css_list);
+
+	BUG_ON(cgroup_css(cgrp, ss));
+}
+
+/* invoke ->css_online() on a new CSS and mark it online if successful */
+static int online_css(struct cgroup_subsys_state *css)
+{
+	struct cgroup_subsys *ss = css->ss;
+	int ret = 0;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	if (ss->css_online)
+		ret = ss->css_online(css);
+	if (!ret) {
+		css->flags |= CSS_ONLINE;
+		rcu_assign_pointer(css->cgroup->subsys[ss->id], css);
+
+		atomic_inc(&css->online_cnt);
+		if (css->parent)
+			atomic_inc(&css->parent->online_cnt);
+	}
+	return ret;
+}
+
+/* if the CSS is online, invoke ->css_offline() on it and mark it offline */
+static void offline_css(struct cgroup_subsys_state *css)
+{
+	struct cgroup_subsys *ss = css->ss;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	if (!(css->flags & CSS_ONLINE))
+		return;
+
+	if (ss->css_offline)
+		ss->css_offline(css);
+
+	css->flags &= ~CSS_ONLINE;
+	RCU_INIT_POINTER(css->cgroup->subsys[ss->id], NULL);
+
+	wake_up_all(&css->cgroup->offline_waitq);
+}
+
+/**
+ * css_create - create a cgroup_subsys_state
+ * @cgrp: the cgroup new css will be associated with
+ * @ss: the subsys of new css
+ *
+ * Create a new css associated with @cgrp - @ss pair.  On success, the new
+ * css is online and installed in @cgrp.  This function doesn't create the
+ * interface files.  Returns 0 on success, -errno on failure.
+ */
+static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
+					      struct cgroup_subsys *ss)
+{
+	struct cgroup *parent = cgroup_parent(cgrp);
+	struct cgroup_subsys_state *parent_css = cgroup_css(parent, ss);
+	struct cgroup_subsys_state *css;
+	int err;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	css = ss->css_alloc(parent_css);
+	if (!css)
+		css = ERR_PTR(-ENOMEM);
+	if (IS_ERR(css))
+		return css;
+
+	init_and_link_css(css, ss, cgrp);
+
+	err = percpu_ref_init(&css->refcnt, css_release, 0, GFP_KERNEL);
+	if (err)
+		goto err_free_css;
+
+	err = cgroup_idr_alloc(&ss->css_idr, NULL, 2, 0, GFP_KERNEL);
+	if (err < 0)
+		goto err_free_css;
+	css->id = err;
+
+	/* @css is ready to be brought online now, make it visible */
+	list_add_tail_rcu(&css->sibling, &parent_css->children);
+	cgroup_idr_replace(&ss->css_idr, css, css->id);
+
+	err = online_css(css);
+	if (err)
+		goto err_list_del;
+
+	return css;
+
+err_list_del:
+	list_del_rcu(&css->sibling);
+err_free_css:
+	list_del_rcu(&css->rstat_css_node);
+	INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
+	queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
+	return ERR_PTR(err);
+}
+
+/*
+ * The returned cgroup is fully initialized including its control mask, but
+ * it isn't associated with its kernfs_node and doesn't have the control
+ * mask applied.
+ */
+static struct cgroup *cgroup_create(struct cgroup *parent, const char *name,
+				    umode_t mode)
+{
+	struct cgroup_root *root = parent->root;
+	struct cgroup *cgrp, *tcgrp;
+	struct kernfs_node *kn;
+	int level = parent->level + 1;
+	int ret;
+
+	/* allocate the cgroup and its ID, 0 is reserved for the root */
+	cgrp = kzalloc(struct_size(cgrp, ancestors, (level + 1)), GFP_KERNEL);
+	if (!cgrp)
+		return ERR_PTR(-ENOMEM);
+
+	ret = percpu_ref_init(&cgrp->self.refcnt, css_release, 0, GFP_KERNEL);
+	if (ret)
+		goto out_free_cgrp;
+
+	ret = cgroup_rstat_init(cgrp);
+	if (ret)
+		goto out_cancel_ref;
+
+	/* create the directory */
+	kn = kernfs_create_dir(parent->kn, name, mode, cgrp);
+	if (IS_ERR(kn)) {
+		ret = PTR_ERR(kn);
+		goto out_stat_exit;
+	}
+	cgrp->kn = kn;
+
+	init_cgroup_housekeeping(cgrp);
+
+	cgrp->self.parent = &parent->self;
+	cgrp->root = root;
+	cgrp->level = level;
+
+	ret = psi_cgroup_alloc(cgrp);
+	if (ret)
+		goto out_kernfs_remove;
+
+	ret = cgroup_bpf_inherit(cgrp);
+	if (ret)
+		goto out_psi_free;
+
+	/*
+	 * New cgroup inherits effective freeze counter, and
+	 * if the parent has to be frozen, the child has too.
+	 */
+	cgrp->freezer.e_freeze = parent->freezer.e_freeze;
+	if (cgrp->freezer.e_freeze) {
+		/*
+		 * Set the CGRP_FREEZE flag, so when a process will be
+		 * attached to the child cgroup, it will become frozen.
+		 * At this point the new cgroup is unpopulated, so we can
+		 * consider it frozen immediately.
+		 */
+		set_bit(CGRP_FREEZE, &cgrp->flags);
+		set_bit(CGRP_FROZEN, &cgrp->flags);
+	}
+
+	spin_lock_irq(&css_set_lock);
+	for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) {
+		cgrp->ancestors[tcgrp->level] = tcgrp;
+
+		if (tcgrp != cgrp) {
+			tcgrp->nr_descendants++;
+
+			/*
+			 * If the new cgroup is frozen, all ancestor cgroups
+			 * get a new frozen descendant, but their state can't
+			 * change because of this.
+			 */
+			if (cgrp->freezer.e_freeze)
+				tcgrp->freezer.nr_frozen_descendants++;
+		}
+	}
+	spin_unlock_irq(&css_set_lock);
+
+	if (notify_on_release(parent))
+		set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
+
+	if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &parent->flags))
+		set_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
+
+	cgrp->self.serial_nr = css_serial_nr_next++;
+
+	/* allocation complete, commit to creation */
+	list_add_tail_rcu(&cgrp->self.sibling, &cgroup_parent(cgrp)->self.children);
+	atomic_inc(&root->nr_cgrps);
+	cgroup_get_live(parent);
+
+	/*
+	 * On the default hierarchy, a child doesn't automatically inherit
+	 * subtree_control from the parent.  Each is configured manually.
+	 */
+	if (!cgroup_on_dfl(cgrp))
+		cgrp->subtree_control = cgroup_control(cgrp);
+
+	cgroup_propagate_control(cgrp);
+
+	return cgrp;
+
+out_psi_free:
+	psi_cgroup_free(cgrp);
+out_kernfs_remove:
+	kernfs_remove(cgrp->kn);
+out_stat_exit:
+	cgroup_rstat_exit(cgrp);
+out_cancel_ref:
+	percpu_ref_exit(&cgrp->self.refcnt);
+out_free_cgrp:
+	kfree(cgrp);
+	return ERR_PTR(ret);
+}
+
+static bool cgroup_check_hierarchy_limits(struct cgroup *parent)
+{
+	struct cgroup *cgroup;
+	int ret = false;
+	int level = 1;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	for (cgroup = parent; cgroup; cgroup = cgroup_parent(cgroup)) {
+		if (cgroup->nr_descendants >= cgroup->max_descendants)
+			goto fail;
+
+		if (level > cgroup->max_depth)
+			goto fail;
+
+		level++;
+	}
+
+	ret = true;
+fail:
+	return ret;
+}
+
+int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode)
+{
+	struct cgroup *parent, *cgrp;
+	int ret;
+
+	/* do not accept '\n' to prevent making /proc/<pid>/cgroup unparsable */
+	if (strchr(name, '\n'))
+		return -EINVAL;
+
+	parent = cgroup_kn_lock_live(parent_kn, false);
+	if (!parent)
+		return -ENODEV;
+
+	if (!cgroup_check_hierarchy_limits(parent)) {
+		ret = -EAGAIN;
+		goto out_unlock;
+	}
+
+	cgrp = cgroup_create(parent, name, mode);
+	if (IS_ERR(cgrp)) {
+		ret = PTR_ERR(cgrp);
+		goto out_unlock;
+	}
+
+	/*
+	 * This extra ref will be put in cgroup_free_fn() and guarantees
+	 * that @cgrp->kn is always accessible.
+	 */
+	kernfs_get(cgrp->kn);
+
+	ret = cgroup_kn_set_ugid(cgrp->kn);
+	if (ret)
+		goto out_destroy;
+
+	ret = css_populate_dir(&cgrp->self);
+	if (ret)
+		goto out_destroy;
+
+	ret = cgroup_apply_control_enable(cgrp);
+	if (ret)
+		goto out_destroy;
+
+	TRACE_CGROUP_PATH(mkdir, cgrp);
+
+	/* let's create and online css's */
+	kernfs_activate(cgrp->kn);
+
+	ret = 0;
+	goto out_unlock;
+
+out_destroy:
+	cgroup_destroy_locked(cgrp);
+out_unlock:
+	cgroup_kn_unlock(parent_kn);
+	return ret;
+}
+
+/*
+ * This is called when the refcnt of a css is confirmed to be killed.
+ * css_tryget_online() is now guaranteed to fail.  Tell the subsystem to
+ * initiate destruction and put the css ref from kill_css().
+ */
+static void css_killed_work_fn(struct work_struct *work)
+{
+	struct cgroup_subsys_state *css =
+		container_of(work, struct cgroup_subsys_state, destroy_work);
+
+	cgroup_lock();
+
+	do {
+		offline_css(css);
+		css_put(css);
+		/* @css can't go away while we're holding cgroup_mutex */
+		css = css->parent;
+	} while (css && atomic_dec_and_test(&css->online_cnt));
+
+	cgroup_unlock();
+}
+
+/* css kill confirmation processing requires process context, bounce */
+static void css_killed_ref_fn(struct percpu_ref *ref)
+{
+	struct cgroup_subsys_state *css =
+		container_of(ref, struct cgroup_subsys_state, refcnt);
+
+	if (atomic_dec_and_test(&css->online_cnt)) {
+		INIT_WORK(&css->destroy_work, css_killed_work_fn);
+		queue_work(cgroup_destroy_wq, &css->destroy_work);
+	}
+}
+
+/**
+ * kill_css - destroy a css
+ * @css: css to destroy
+ *
+ * This function initiates destruction of @css by removing cgroup interface
+ * files and putting its base reference.  ->css_offline() will be invoked
+ * asynchronously once css_tryget_online() is guaranteed to fail and when
+ * the reference count reaches zero, @css will be released.
+ */
+static void kill_css(struct cgroup_subsys_state *css)
+{
+	lockdep_assert_held(&cgroup_mutex);
+
+	if (css->flags & CSS_DYING)
+		return;
+
+	css->flags |= CSS_DYING;
+
+	/*
+	 * This must happen before css is disassociated with its cgroup.
+	 * See seq_css() for details.
+	 */
+	css_clear_dir(css);
+
+	/*
+	 * Killing would put the base ref, but we need to keep it alive
+	 * until after ->css_offline().
+	 */
+	css_get(css);
+
+	/*
+	 * cgroup core guarantees that, by the time ->css_offline() is
+	 * invoked, no new css reference will be given out via
+	 * css_tryget_online().  We can't simply call percpu_ref_kill() and
+	 * proceed to offlining css's because percpu_ref_kill() doesn't
+	 * guarantee that the ref is seen as killed on all CPUs on return.
+	 *
+	 * Use percpu_ref_kill_and_confirm() to get notifications as each
+	 * css is confirmed to be seen as killed on all CPUs.
+	 */
+	percpu_ref_kill_and_confirm(&css->refcnt, css_killed_ref_fn);
+}
+
+/**
+ * cgroup_destroy_locked - the first stage of cgroup destruction
+ * @cgrp: cgroup to be destroyed
+ *
+ * css's make use of percpu refcnts whose killing latency shouldn't be
+ * exposed to userland and are RCU protected.  Also, cgroup core needs to
+ * guarantee that css_tryget_online() won't succeed by the time
+ * ->css_offline() is invoked.  To satisfy all the requirements,
+ * destruction is implemented in the following two steps.
+ *
+ * s1. Verify @cgrp can be destroyed and mark it dying.  Remove all
+ *     userland visible parts and start killing the percpu refcnts of
+ *     css's.  Set up so that the next stage will be kicked off once all
+ *     the percpu refcnts are confirmed to be killed.
+ *
+ * s2. Invoke ->css_offline(), mark the cgroup dead and proceed with the
+ *     rest of destruction.  Once all cgroup references are gone, the
+ *     cgroup is RCU-freed.
+ *
+ * This function implements s1.  After this step, @cgrp is gone as far as
+ * the userland is concerned and a new cgroup with the same name may be
+ * created.  As cgroup doesn't care about the names internally, this
+ * doesn't cause any problem.
+ */
+static int cgroup_destroy_locked(struct cgroup *cgrp)
+	__releases(&cgroup_mutex) __acquires(&cgroup_mutex)
+{
+	struct cgroup *tcgrp, *parent = cgroup_parent(cgrp);
+	struct cgroup_subsys_state *css;
+	struct cgrp_cset_link *link;
+	int ssid;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	/*
+	 * Only migration can raise populated from zero and we're already
+	 * holding cgroup_mutex.
+	 */
+	if (cgroup_is_populated(cgrp))
+		return -EBUSY;
+
+	/*
+	 * Make sure there's no live children.  We can't test emptiness of
+	 * ->self.children as dead children linger on it while being
+	 * drained; otherwise, "rmdir parent/child parent" may fail.
+	 */
+	if (css_has_online_children(&cgrp->self))
+		return -EBUSY;
+
+	/*
+	 * Mark @cgrp and the associated csets dead.  The former prevents
+	 * further task migration and child creation by disabling
+	 * cgroup_lock_live_group().  The latter makes the csets ignored by
+	 * the migration path.
+	 */
+	cgrp->self.flags &= ~CSS_ONLINE;
+
+	spin_lock_irq(&css_set_lock);
+	list_for_each_entry(link, &cgrp->cset_links, cset_link)
+		link->cset->dead = true;
+	spin_unlock_irq(&css_set_lock);
+
+	/* initiate massacre of all css's */
+	for_each_css(css, ssid, cgrp)
+		kill_css(css);
+
+	/* clear and remove @cgrp dir, @cgrp has an extra ref on its kn */
+	css_clear_dir(&cgrp->self);
+	kernfs_remove(cgrp->kn);
+
+	if (cgroup_is_threaded(cgrp))
+		parent->nr_threaded_children--;
+
+	spin_lock_irq(&css_set_lock);
+	for (tcgrp = cgroup_parent(cgrp); tcgrp; tcgrp = cgroup_parent(tcgrp)) {
+		tcgrp->nr_descendants--;
+		tcgrp->nr_dying_descendants++;
+		/*
+		 * If the dying cgroup is frozen, decrease frozen descendants
+		 * counters of ancestor cgroups.
+		 */
+		if (test_bit(CGRP_FROZEN, &cgrp->flags))
+			tcgrp->freezer.nr_frozen_descendants--;
+	}
+	spin_unlock_irq(&css_set_lock);
+
+	cgroup1_check_for_release(parent);
+
+	cgroup_bpf_offline(cgrp);
+
+	/* put the base reference */
+	percpu_ref_kill(&cgrp->self.refcnt);
+
+	return 0;
+};
+
+int cgroup_rmdir(struct kernfs_node *kn)
+{
+	struct cgroup *cgrp;
+	int ret = 0;
+
+	cgrp = cgroup_kn_lock_live(kn, false);
+	if (!cgrp)
+		return 0;
+
+	ret = cgroup_destroy_locked(cgrp);
+	if (!ret)
+		TRACE_CGROUP_PATH(rmdir, cgrp);
+
+	cgroup_kn_unlock(kn);
+	return ret;
+}
+
+static struct kernfs_syscall_ops cgroup_kf_syscall_ops = {
+	.show_options		= cgroup_show_options,
+	.mkdir			= cgroup_mkdir,
+	.rmdir			= cgroup_rmdir,
+	.show_path		= cgroup_show_path,
+};
+
+static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early)
+{
+	struct cgroup_subsys_state *css;
+
+	pr_debug("Initializing cgroup subsys %s\n", ss->name);
+
+	cgroup_lock();
+
+	idr_init(&ss->css_idr);
+	INIT_LIST_HEAD(&ss->cfts);
+
+	/* Create the root cgroup state for this subsystem */
+	ss->root = &cgrp_dfl_root;
+	css = ss->css_alloc(NULL);
+	/* We don't handle early failures gracefully */
+	BUG_ON(IS_ERR(css));
+	init_and_link_css(css, ss, &cgrp_dfl_root.cgrp);
+
+	/*
+	 * Root csses are never destroyed and we can't initialize
+	 * percpu_ref during early init.  Disable refcnting.
+	 */
+	css->flags |= CSS_NO_REF;
+
+	if (early) {
+		/* allocation can't be done safely during early init */
+		css->id = 1;
+	} else {
+		css->id = cgroup_idr_alloc(&ss->css_idr, css, 1, 2, GFP_KERNEL);
+		BUG_ON(css->id < 0);
+	}
+
+	/* Update the init_css_set to contain a subsys
+	 * pointer to this state - since the subsystem is
+	 * newly registered, all tasks and hence the
+	 * init_css_set is in the subsystem's root cgroup. */
+	init_css_set.subsys[ss->id] = css;
+
+	have_fork_callback |= (bool)ss->fork << ss->id;
+	have_exit_callback |= (bool)ss->exit << ss->id;
+	have_release_callback |= (bool)ss->release << ss->id;
+	have_canfork_callback |= (bool)ss->can_fork << ss->id;
+
+	/* At system boot, before all subsystems have been
+	 * registered, no tasks have been forked, so we don't
+	 * need to invoke fork callbacks here. */
+	BUG_ON(!list_empty(&init_task.tasks));
+
+	BUG_ON(online_css(css));
+
+	cgroup_unlock();
+}
+
+/**
+ * cgroup_init_early - cgroup initialization at system boot
+ *
+ * Initialize cgroups at system boot, and initialize any
+ * subsystems that request early init.
+ */
+int __init cgroup_init_early(void)
+{
+	static struct cgroup_fs_context __initdata ctx;
+	struct cgroup_subsys *ss;
+	int i;
+
+	ctx.root = &cgrp_dfl_root;
+	init_cgroup_root(&ctx);
+	cgrp_dfl_root.cgrp.self.flags |= CSS_NO_REF;
+
+	RCU_INIT_POINTER(init_task.cgroups, &init_css_set);
+
+	for_each_subsys(ss, i) {
+		WARN(!ss->css_alloc || !ss->css_free || ss->name || ss->id,
+		     "invalid cgroup_subsys %d:%s css_alloc=%p css_free=%p id:name=%d:%s\n",
+		     i, cgroup_subsys_name[i], ss->css_alloc, ss->css_free,
+		     ss->id, ss->name);
+		WARN(strlen(cgroup_subsys_name[i]) > MAX_CGROUP_TYPE_NAMELEN,
+		     "cgroup_subsys_name %s too long\n", cgroup_subsys_name[i]);
+
+		ss->id = i;
+		ss->name = cgroup_subsys_name[i];
+		if (!ss->legacy_name)
+			ss->legacy_name = cgroup_subsys_name[i];
+
+		if (ss->early_init)
+			cgroup_init_subsys(ss, true);
+	}
+	return 0;
+}
+
+/**
+ * cgroup_init - cgroup initialization
+ *
+ * Register cgroup filesystem and /proc file, and initialize
+ * any subsystems that didn't request early init.
+ */
+int __init cgroup_init(void)
+{
+	struct cgroup_subsys *ss;
+	int ssid;
+
+	BUILD_BUG_ON(CGROUP_SUBSYS_COUNT > 16);
+	BUG_ON(cgroup_init_cftypes(NULL, cgroup_base_files));
+	BUG_ON(cgroup_init_cftypes(NULL, cgroup_psi_files));
+	BUG_ON(cgroup_init_cftypes(NULL, cgroup1_base_files));
+
+	cgroup_rstat_boot();
+
+	get_user_ns(init_cgroup_ns.user_ns);
+
+	cgroup_lock();
+
+	/*
+	 * Add init_css_set to the hash table so that dfl_root can link to
+	 * it during init.
+	 */
+	hash_add(css_set_table, &init_css_set.hlist,
+		 css_set_hash(init_css_set.subsys));
+
+	BUG_ON(cgroup_setup_root(&cgrp_dfl_root, 0));
+
+	cgroup_unlock();
+
+	for_each_subsys(ss, ssid) {
+		if (ss->early_init) {
+			struct cgroup_subsys_state *css =
+				init_css_set.subsys[ss->id];
+
+			css->id = cgroup_idr_alloc(&ss->css_idr, css, 1, 2,
+						   GFP_KERNEL);
+			BUG_ON(css->id < 0);
+		} else {
+			cgroup_init_subsys(ss, false);
+		}
+
+		list_add_tail(&init_css_set.e_cset_node[ssid],
+			      &cgrp_dfl_root.cgrp.e_csets[ssid]);
+
+		/*
+		 * Setting dfl_root subsys_mask needs to consider the
+		 * disabled flag and cftype registration needs kmalloc,
+		 * both of which aren't available during early_init.
+		 */
+		if (!cgroup_ssid_enabled(ssid))
+			continue;
+
+		if (cgroup1_ssid_disabled(ssid))
+			printk(KERN_INFO "Disabling %s control group subsystem in v1 mounts\n",
+			       ss->name);
+
+		cgrp_dfl_root.subsys_mask |= 1 << ss->id;
+
+		/* implicit controllers must be threaded too */
+		WARN_ON(ss->implicit_on_dfl && !ss->threaded);
+
+		if (ss->implicit_on_dfl)
+			cgrp_dfl_implicit_ss_mask |= 1 << ss->id;
+		else if (!ss->dfl_cftypes)
+			cgrp_dfl_inhibit_ss_mask |= 1 << ss->id;
+
+		if (ss->threaded)
+			cgrp_dfl_threaded_ss_mask |= 1 << ss->id;
+
+		if (ss->dfl_cftypes == ss->legacy_cftypes) {
+			WARN_ON(cgroup_add_cftypes(ss, ss->dfl_cftypes));
+		} else {
+			WARN_ON(cgroup_add_dfl_cftypes(ss, ss->dfl_cftypes));
+			WARN_ON(cgroup_add_legacy_cftypes(ss, ss->legacy_cftypes));
+		}
+
+		if (ss->bind)
+			ss->bind(init_css_set.subsys[ssid]);
+
+		cgroup_lock();
+		css_populate_dir(init_css_set.subsys[ssid]);
+		cgroup_unlock();
+	}
+
+	/* init_css_set.subsys[] has been updated, re-hash */
+	hash_del(&init_css_set.hlist);
+	hash_add(css_set_table, &init_css_set.hlist,
+		 css_set_hash(init_css_set.subsys));
+
+	WARN_ON(sysfs_create_mount_point(fs_kobj, "cgroup"));
+	WARN_ON(register_filesystem(&cgroup_fs_type));
+	WARN_ON(register_filesystem(&cgroup2_fs_type));
+	WARN_ON(!proc_create_single("cgroups", 0, NULL, proc_cgroupstats_show));
+#ifdef CONFIG_CPUSETS
+	WARN_ON(register_filesystem(&cpuset_fs_type));
+#endif
+
+	return 0;
+}
+
+static int __init cgroup_wq_init(void)
+{
+	/*
+	 * There isn't much point in executing destruction path in
+	 * parallel.  Good chunk is serialized with cgroup_mutex anyway.
+	 * Use 1 for @max_active.
+	 *
+	 * We would prefer to do this in cgroup_init() above, but that
+	 * is called before init_workqueues(): so leave this until after.
+	 */
+	cgroup_destroy_wq = alloc_workqueue("cgroup_destroy", 0, 1);
+	BUG_ON(!cgroup_destroy_wq);
+	return 0;
+}
+core_initcall(cgroup_wq_init);
+
+void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
+{
+	struct kernfs_node *kn;
+
+	kn = kernfs_find_and_get_node_by_id(cgrp_dfl_root.kf_root, id);
+	if (!kn)
+		return;
+	kernfs_path(kn, buf, buflen);
+	kernfs_put(kn);
+}
+
+/*
+ * cgroup_get_from_id : get the cgroup associated with cgroup id
+ * @id: cgroup id
+ * On success return the cgrp or ERR_PTR on failure
+ * Only cgroups within current task's cgroup NS are valid.
+ */
+struct cgroup *cgroup_get_from_id(u64 id)
+{
+	struct kernfs_node *kn;
+	struct cgroup *cgrp, *root_cgrp;
+
+	kn = kernfs_find_and_get_node_by_id(cgrp_dfl_root.kf_root, id);
+	if (!kn)
+		return ERR_PTR(-ENOENT);
+
+	if (kernfs_type(kn) != KERNFS_DIR) {
+		kernfs_put(kn);
+		return ERR_PTR(-ENOENT);
+	}
+
+	rcu_read_lock();
+
+	cgrp = rcu_dereference(*(void __rcu __force **)&kn->priv);
+	if (cgrp && !cgroup_tryget(cgrp))
+		cgrp = NULL;
+
+	rcu_read_unlock();
+	kernfs_put(kn);
+
+	if (!cgrp)
+		return ERR_PTR(-ENOENT);
+
+	root_cgrp = current_cgns_cgroup_dfl();
+	if (!cgroup_is_descendant(cgrp, root_cgrp)) {
+		cgroup_put(cgrp);
+		return ERR_PTR(-ENOENT);
+	}
+
+	return cgrp;
+}
+EXPORT_SYMBOL_GPL(cgroup_get_from_id);
+
+/*
+ * proc_cgroup_show()
+ *  - Print task's cgroup paths into seq_file, one line for each hierarchy
+ *  - Used for /proc/<pid>/cgroup.
+ */
+int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
+		     struct pid *pid, struct task_struct *tsk)
+{
+	char *buf;
+	int retval;
+	struct cgroup_root *root;
+
+	retval = -ENOMEM;
+	buf = kmalloc(PATH_MAX, GFP_KERNEL);
+	if (!buf)
+		goto out;
+
+	cgroup_lock();
+	spin_lock_irq(&css_set_lock);
+
+	for_each_root(root) {
+		struct cgroup_subsys *ss;
+		struct cgroup *cgrp;
+		int ssid, count = 0;
+
+		if (root == &cgrp_dfl_root && !READ_ONCE(cgrp_dfl_visible))
+			continue;
+
+		seq_printf(m, "%d:", root->hierarchy_id);
+		if (root != &cgrp_dfl_root)
+			for_each_subsys(ss, ssid)
+				if (root->subsys_mask & (1 << ssid))
+					seq_printf(m, "%s%s", count++ ? "," : "",
+						   ss->legacy_name);
+		if (strlen(root->name))
+			seq_printf(m, "%sname=%s", count ? "," : "",
+				   root->name);
+		seq_putc(m, ':');
+
+		cgrp = task_cgroup_from_root(tsk, root);
+
+		/*
+		 * On traditional hierarchies, all zombie tasks show up as
+		 * belonging to the root cgroup.  On the default hierarchy,
+		 * while a zombie doesn't show up in "cgroup.procs" and
+		 * thus can't be migrated, its /proc/PID/cgroup keeps
+		 * reporting the cgroup it belonged to before exiting.  If
+		 * the cgroup is removed before the zombie is reaped,
+		 * " (deleted)" is appended to the cgroup path.
+		 */
+		if (cgroup_on_dfl(cgrp) || !(tsk->flags & PF_EXITING)) {
+			retval = cgroup_path_ns_locked(cgrp, buf, PATH_MAX,
+						current->nsproxy->cgroup_ns);
+			if (retval >= PATH_MAX)
+				retval = -ENAMETOOLONG;
+			if (retval < 0)
+				goto out_unlock;
+
+			seq_puts(m, buf);
+		} else {
+			seq_puts(m, "/");
+		}
+
+		if (cgroup_on_dfl(cgrp) && cgroup_is_dead(cgrp))
+			seq_puts(m, " (deleted)\n");
+		else
+			seq_putc(m, '\n');
+	}
+
+	retval = 0;
+out_unlock:
+	spin_unlock_irq(&css_set_lock);
+	cgroup_unlock();
+	kfree(buf);
+out:
+	return retval;
+}
+
+/**
+ * cgroup_fork - initialize cgroup related fields during copy_process()
+ * @child: pointer to task_struct of forking parent process.
+ *
+ * A task is associated with the init_css_set until cgroup_post_fork()
+ * attaches it to the target css_set.
+ */
+void cgroup_fork(struct task_struct *child)
+{
+	RCU_INIT_POINTER(child->cgroups, &init_css_set);
+	INIT_LIST_HEAD(&child->cg_list);
+}
+
+/**
+ * cgroup_v1v2_get_from_file - get a cgroup pointer from a file pointer
+ * @f: file corresponding to cgroup_dir
+ *
+ * Find the cgroup from a file pointer associated with a cgroup directory.
+ * Returns a pointer to the cgroup on success. ERR_PTR is returned if the
+ * cgroup cannot be found.
+ */
+static struct cgroup *cgroup_v1v2_get_from_file(struct file *f)
+{
+	struct cgroup_subsys_state *css;
+
+	css = css_tryget_online_from_dir(f->f_path.dentry, NULL);
+	if (IS_ERR(css))
+		return ERR_CAST(css);
+
+	return css->cgroup;
+}
+
+/**
+ * cgroup_get_from_file - same as cgroup_v1v2_get_from_file, but only supports
+ * cgroup2.
+ * @f: file corresponding to cgroup2_dir
+ */
+static struct cgroup *cgroup_get_from_file(struct file *f)
+{
+	struct cgroup *cgrp = cgroup_v1v2_get_from_file(f);
+
+	if (IS_ERR(cgrp))
+		return ERR_CAST(cgrp);
+
+	if (!cgroup_on_dfl(cgrp)) {
+		cgroup_put(cgrp);
+		return ERR_PTR(-EBADF);
+	}
+
+	return cgrp;
+}
+
+/**
+ * cgroup_css_set_fork - find or create a css_set for a child process
+ * @kargs: the arguments passed to create the child process
+ *
+ * This functions finds or creates a new css_set which the child
+ * process will be attached to in cgroup_post_fork(). By default,
+ * the child process will be given the same css_set as its parent.
+ *
+ * If CLONE_INTO_CGROUP is specified this function will try to find an
+ * existing css_set which includes the requested cgroup and if not create
+ * a new css_set that the child will be attached to later. If this function
+ * succeeds it will hold cgroup_threadgroup_rwsem on return. If
+ * CLONE_INTO_CGROUP is requested this function will grab cgroup mutex
+ * before grabbing cgroup_threadgroup_rwsem and will hold a reference
+ * to the target cgroup.
+ */
+static int cgroup_css_set_fork(struct kernel_clone_args *kargs)
+	__acquires(&cgroup_mutex) __acquires(&cgroup_threadgroup_rwsem)
+{
+	int ret;
+	struct cgroup *dst_cgrp = NULL;
+	struct css_set *cset;
+	struct super_block *sb;
+	struct file *f;
+
+	if (kargs->flags & CLONE_INTO_CGROUP)
+		cgroup_lock();
+
+	cgroup_threadgroup_change_begin(current);
+
+	spin_lock_irq(&css_set_lock);
+	cset = task_css_set(current);
+	get_css_set(cset);
+	spin_unlock_irq(&css_set_lock);
+
+	if (!(kargs->flags & CLONE_INTO_CGROUP)) {
+		kargs->cset = cset;
+		return 0;
+	}
+
+	f = fget_raw(kargs->cgroup);
+	if (!f) {
+		ret = -EBADF;
+		goto err;
+	}
+	sb = f->f_path.dentry->d_sb;
+
+	dst_cgrp = cgroup_get_from_file(f);
+	if (IS_ERR(dst_cgrp)) {
+		ret = PTR_ERR(dst_cgrp);
+		dst_cgrp = NULL;
+		goto err;
+	}
+
+	if (cgroup_is_dead(dst_cgrp)) {
+		ret = -ENODEV;
+		goto err;
+	}
+
+	/*
+	 * Verify that we the target cgroup is writable for us. This is
+	 * usually done by the vfs layer but since we're not going through
+	 * the vfs layer here we need to do it "manually".
+	 */
+	ret = cgroup_may_write(dst_cgrp, sb);
+	if (ret)
+		goto err;
+
+	/*
+	 * Spawning a task directly into a cgroup works by passing a file
+	 * descriptor to the target cgroup directory. This can even be an O_PATH
+	 * file descriptor. But it can never be a cgroup.procs file descriptor.
+	 * This was done on purpose so spawning into a cgroup could be
+	 * conceptualized as an atomic
+	 *
+	 *   fd = openat(dfd_cgroup, "cgroup.procs", ...);
+	 *   write(fd, <child-pid>, ...);
+	 *
+	 * sequence, i.e. it's a shorthand for the caller opening and writing
+	 * cgroup.procs of the cgroup indicated by @dfd_cgroup. This allows us
+	 * to always use the caller's credentials.
+	 */
+	ret = cgroup_attach_permissions(cset->dfl_cgrp, dst_cgrp, sb,
+					!(kargs->flags & CLONE_THREAD),
+					current->nsproxy->cgroup_ns);
+	if (ret)
+		goto err;
+
+	kargs->cset = find_css_set(cset, dst_cgrp);
+	if (!kargs->cset) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	put_css_set(cset);
+	fput(f);
+	kargs->cgrp = dst_cgrp;
+	return ret;
+
+err:
+	cgroup_threadgroup_change_end(current);
+	cgroup_unlock();
+	if (f)
+		fput(f);
+	if (dst_cgrp)
+		cgroup_put(dst_cgrp);
+	put_css_set(cset);
+	if (kargs->cset)
+		put_css_set(kargs->cset);
+	return ret;
+}
+
+/**
+ * cgroup_css_set_put_fork - drop references we took during fork
+ * @kargs: the arguments passed to create the child process
+ *
+ * Drop references to the prepared css_set and target cgroup if
+ * CLONE_INTO_CGROUP was requested.
+ */
+static void cgroup_css_set_put_fork(struct kernel_clone_args *kargs)
+	__releases(&cgroup_threadgroup_rwsem) __releases(&cgroup_mutex)
+{
+	struct cgroup *cgrp = kargs->cgrp;
+	struct css_set *cset = kargs->cset;
+
+	cgroup_threadgroup_change_end(current);
+
+	if (cset) {
+		put_css_set(cset);
+		kargs->cset = NULL;
+	}
+
+	if (kargs->flags & CLONE_INTO_CGROUP) {
+		cgroup_unlock();
+		if (cgrp) {
+			cgroup_put(cgrp);
+			kargs->cgrp = NULL;
+		}
+	}
+}
+
+/**
+ * cgroup_can_fork - called on a new task before the process is exposed
+ * @child: the child process
+ * @kargs: the arguments passed to create the child process
+ *
+ * This prepares a new css_set for the child process which the child will
+ * be attached to in cgroup_post_fork().
+ * This calls the subsystem can_fork() callbacks. If the cgroup_can_fork()
+ * callback returns an error, the fork aborts with that error code. This
+ * allows for a cgroup subsystem to conditionally allow or deny new forks.
+ */
+int cgroup_can_fork(struct task_struct *child, struct kernel_clone_args *kargs)
+{
+	struct cgroup_subsys *ss;
+	int i, j, ret;
+
+	ret = cgroup_css_set_fork(kargs);
+	if (ret)
+		return ret;
+
+	do_each_subsys_mask(ss, i, have_canfork_callback) {
+		ret = ss->can_fork(child, kargs->cset);
+		if (ret)
+			goto out_revert;
+	} while_each_subsys_mask();
+
+	return 0;
+
+out_revert:
+	for_each_subsys(ss, j) {
+		if (j >= i)
+			break;
+		if (ss->cancel_fork)
+			ss->cancel_fork(child, kargs->cset);
+	}
+
+	cgroup_css_set_put_fork(kargs);
+
+	return ret;
+}
+
+/**
+ * cgroup_cancel_fork - called if a fork failed after cgroup_can_fork()
+ * @child: the child process
+ * @kargs: the arguments passed to create the child process
+ *
+ * This calls the cancel_fork() callbacks if a fork failed *after*
+ * cgroup_can_fork() succeeded and cleans up references we took to
+ * prepare a new css_set for the child process in cgroup_can_fork().
+ */
+void cgroup_cancel_fork(struct task_struct *child,
+			struct kernel_clone_args *kargs)
+{
+	struct cgroup_subsys *ss;
+	int i;
+
+	for_each_subsys(ss, i)
+		if (ss->cancel_fork)
+			ss->cancel_fork(child, kargs->cset);
+
+	cgroup_css_set_put_fork(kargs);
+}
+
+/**
+ * cgroup_post_fork - finalize cgroup setup for the child process
+ * @child: the child process
+ * @kargs: the arguments passed to create the child process
+ *
+ * Attach the child process to its css_set calling the subsystem fork()
+ * callbacks.
+ */
+void cgroup_post_fork(struct task_struct *child,
+		      struct kernel_clone_args *kargs)
+	__releases(&cgroup_threadgroup_rwsem) __releases(&cgroup_mutex)
+{
+	unsigned long cgrp_flags = 0;
+	bool kill = false;
+	struct cgroup_subsys *ss;
+	struct css_set *cset;
+	int i;
+
+	cset = kargs->cset;
+	kargs->cset = NULL;
+
+	spin_lock_irq(&css_set_lock);
+
+	/* init tasks are special, only link regular threads */
+	if (likely(child->pid)) {
+		if (kargs->cgrp)
+			cgrp_flags = kargs->cgrp->flags;
+		else
+			cgrp_flags = cset->dfl_cgrp->flags;
+
+		WARN_ON_ONCE(!list_empty(&child->cg_list));
+		cset->nr_tasks++;
+		css_set_move_task(child, NULL, cset, false);
+	} else {
+		put_css_set(cset);
+		cset = NULL;
+	}
+
+	if (!(child->flags & PF_KTHREAD)) {
+		if (unlikely(test_bit(CGRP_FREEZE, &cgrp_flags))) {
+			/*
+			 * If the cgroup has to be frozen, the new task has
+			 * too. Let's set the JOBCTL_TRAP_FREEZE jobctl bit to
+			 * get the task into the frozen state.
+			 */
+			spin_lock(&child->sighand->siglock);
+			WARN_ON_ONCE(child->frozen);
+			child->jobctl |= JOBCTL_TRAP_FREEZE;
+			spin_unlock(&child->sighand->siglock);
+
+			/*
+			 * Calling cgroup_update_frozen() isn't required here,
+			 * because it will be called anyway a bit later from
+			 * do_freezer_trap(). So we avoid cgroup's transient
+			 * switch from the frozen state and back.
+			 */
+		}
+
+		/*
+		 * If the cgroup is to be killed notice it now and take the
+		 * child down right after we finished preparing it for
+		 * userspace.
+		 */
+		kill = test_bit(CGRP_KILL, &cgrp_flags);
+	}
+
+	spin_unlock_irq(&css_set_lock);
+
+	/*
+	 * Call ss->fork().  This must happen after @child is linked on
+	 * css_set; otherwise, @child might change state between ->fork()
+	 * and addition to css_set.
+	 */
+	do_each_subsys_mask(ss, i, have_fork_callback) {
+		ss->fork(child);
+	} while_each_subsys_mask();
+
+	/* Make the new cset the root_cset of the new cgroup namespace. */
+	if (kargs->flags & CLONE_NEWCGROUP) {
+		struct css_set *rcset = child->nsproxy->cgroup_ns->root_cset;
+
+		get_css_set(cset);
+		child->nsproxy->cgroup_ns->root_cset = cset;
+		put_css_set(rcset);
+	}
+
+	/* Cgroup has to be killed so take down child immediately. */
+	if (unlikely(kill))
+		do_send_sig_info(SIGKILL, SEND_SIG_NOINFO, child, PIDTYPE_TGID);
+
+	cgroup_css_set_put_fork(kargs);
+}
+
+/**
+ * cgroup_exit - detach cgroup from exiting task
+ * @tsk: pointer to task_struct of exiting process
+ *
+ * Description: Detach cgroup from @tsk.
+ *
+ */
+void cgroup_exit(struct task_struct *tsk)
+{
+	struct cgroup_subsys *ss;
+	struct css_set *cset;
+	int i;
+
+	spin_lock_irq(&css_set_lock);
+
+	WARN_ON_ONCE(list_empty(&tsk->cg_list));
+	cset = task_css_set(tsk);
+	css_set_move_task(tsk, cset, NULL, false);
+	list_add_tail(&tsk->cg_list, &cset->dying_tasks);
+	cset->nr_tasks--;
+
+	if (dl_task(tsk))
+		dec_dl_tasks_cs(tsk);
+
+	WARN_ON_ONCE(cgroup_task_frozen(tsk));
+	if (unlikely(!(tsk->flags & PF_KTHREAD) &&
+		     test_bit(CGRP_FREEZE, &task_dfl_cgroup(tsk)->flags)))
+		cgroup_update_frozen(task_dfl_cgroup(tsk));
+
+	spin_unlock_irq(&css_set_lock);
+
+	/* see cgroup_post_fork() for details */
+	do_each_subsys_mask(ss, i, have_exit_callback) {
+		ss->exit(tsk);
+	} while_each_subsys_mask();
+}
+
+void cgroup_release(struct task_struct *task)
+{
+	struct cgroup_subsys *ss;
+	int ssid;
+
+	do_each_subsys_mask(ss, ssid, have_release_callback) {
+		ss->release(task);
+	} while_each_subsys_mask();
+
+	spin_lock_irq(&css_set_lock);
+	css_set_skip_task_iters(task_css_set(task), task);
+	list_del_init(&task->cg_list);
+	spin_unlock_irq(&css_set_lock);
+}
+
+void cgroup_free(struct task_struct *task)
+{
+	struct css_set *cset = task_css_set(task);
+	put_css_set(cset);
+}
+
+static int __init cgroup_disable(char *str)
+{
+	struct cgroup_subsys *ss;
+	char *token;
+	int i;
+
+	while ((token = strsep(&str, ",")) != NULL) {
+		if (!*token)
+			continue;
+
+		for_each_subsys(ss, i) {
+			if (strcmp(token, ss->name) &&
+			    strcmp(token, ss->legacy_name))
+				continue;
+
+			static_branch_disable(cgroup_subsys_enabled_key[i]);
+			pr_info("Disabling %s control group subsystem\n",
+				ss->name);
+		}
+
+		for (i = 0; i < OPT_FEATURE_COUNT; i++) {
+			if (strcmp(token, cgroup_opt_feature_names[i]))
+				continue;
+			cgroup_feature_disable_mask |= 1 << i;
+			pr_info("Disabling %s control group feature\n",
+				cgroup_opt_feature_names[i]);
+			break;
+		}
+	}
+	return 1;
+}
+__setup("cgroup_disable=", cgroup_disable);
+
+void __init __weak enable_debug_cgroup(void) { }
+
+static int __init enable_cgroup_debug(char *str)
+{
+	cgroup_debug = true;
+	enable_debug_cgroup();
+	return 1;
+}
+__setup("cgroup_debug", enable_cgroup_debug);
+
+/**
+ * css_tryget_online_from_dir - get corresponding css from a cgroup dentry
+ * @dentry: directory dentry of interest
+ * @ss: subsystem of interest
+ *
+ * If @dentry is a directory for a cgroup which has @ss enabled on it, try
+ * to get the corresponding css and return it.  If such css doesn't exist
+ * or can't be pinned, an ERR_PTR value is returned.
+ */
+struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
+						       struct cgroup_subsys *ss)
+{
+	struct kernfs_node *kn = kernfs_node_from_dentry(dentry);
+	struct file_system_type *s_type = dentry->d_sb->s_type;
+	struct cgroup_subsys_state *css = NULL;
+	struct cgroup *cgrp;
+
+	/* is @dentry a cgroup dir? */
+	if ((s_type != &cgroup_fs_type && s_type != &cgroup2_fs_type) ||
+	    !kn || kernfs_type(kn) != KERNFS_DIR)
+		return ERR_PTR(-EBADF);
+
+	rcu_read_lock();
+
+	/*
+	 * This path doesn't originate from kernfs and @kn could already
+	 * have been or be removed at any point.  @kn->priv is RCU
+	 * protected for this access.  See css_release_work_fn() for details.
+	 */
+	cgrp = rcu_dereference(*(void __rcu __force **)&kn->priv);
+	if (cgrp)
+		css = cgroup_css(cgrp, ss);
+
+	if (!css || !css_tryget_online(css))
+		css = ERR_PTR(-ENOENT);
+
+	rcu_read_unlock();
+	return css;
+}
+
+/**
+ * css_from_id - lookup css by id
+ * @id: the cgroup id
+ * @ss: cgroup subsys to be looked into
+ *
+ * Returns the css if there's valid one with @id, otherwise returns NULL.
+ * Should be called under rcu_read_lock().
+ */
+struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
+{
+	WARN_ON_ONCE(!rcu_read_lock_held());
+	return idr_find(&ss->css_idr, id);
+}
+
+/**
+ * cgroup_get_from_path - lookup and get a cgroup from its default hierarchy path
+ * @path: path on the default hierarchy
+ *
+ * Find the cgroup at @path on the default hierarchy, increment its
+ * reference count and return it.  Returns pointer to the found cgroup on
+ * success, ERR_PTR(-ENOENT) if @path doesn't exist or if the cgroup has already
+ * been released and ERR_PTR(-ENOTDIR) if @path points to a non-directory.
+ */
+struct cgroup *cgroup_get_from_path(const char *path)
+{
+	struct kernfs_node *kn;
+	struct cgroup *cgrp = ERR_PTR(-ENOENT);
+	struct cgroup *root_cgrp;
+
+	root_cgrp = current_cgns_cgroup_dfl();
+	kn = kernfs_walk_and_get(root_cgrp->kn, path);
+	if (!kn)
+		goto out;
+
+	if (kernfs_type(kn) != KERNFS_DIR) {
+		cgrp = ERR_PTR(-ENOTDIR);
+		goto out_kernfs;
+	}
+
+	rcu_read_lock();
+
+	cgrp = rcu_dereference(*(void __rcu __force **)&kn->priv);
+	if (!cgrp || !cgroup_tryget(cgrp))
+		cgrp = ERR_PTR(-ENOENT);
+
+	rcu_read_unlock();
+
+out_kernfs:
+	kernfs_put(kn);
+out:
+	return cgrp;
+}
+EXPORT_SYMBOL_GPL(cgroup_get_from_path);
+
+/**
+ * cgroup_v1v2_get_from_fd - get a cgroup pointer from a fd
+ * @fd: fd obtained by open(cgroup_dir)
+ *
+ * Find the cgroup from a fd which should be obtained
+ * by opening a cgroup directory.  Returns a pointer to the
+ * cgroup on success. ERR_PTR is returned if the cgroup
+ * cannot be found.
+ */
+struct cgroup *cgroup_v1v2_get_from_fd(int fd)
+{
+	struct cgroup *cgrp;
+	struct file *f;
+
+	f = fget_raw(fd);
+	if (!f)
+		return ERR_PTR(-EBADF);
+
+	cgrp = cgroup_v1v2_get_from_file(f);
+	fput(f);
+	return cgrp;
+}
+
+/**
+ * cgroup_get_from_fd - same as cgroup_v1v2_get_from_fd, but only supports
+ * cgroup2.
+ * @fd: fd obtained by open(cgroup2_dir)
+ */
+struct cgroup *cgroup_get_from_fd(int fd)
+{
+	struct cgroup *cgrp = cgroup_v1v2_get_from_fd(fd);
+
+	if (IS_ERR(cgrp))
+		return ERR_CAST(cgrp);
+
+	if (!cgroup_on_dfl(cgrp)) {
+		cgroup_put(cgrp);
+		return ERR_PTR(-EBADF);
+	}
+	return cgrp;
+}
+EXPORT_SYMBOL_GPL(cgroup_get_from_fd);
+
+static u64 power_of_ten(int power)
+{
+	u64 v = 1;
+	while (power--)
+		v *= 10;
+	return v;
+}
+
+/**
+ * cgroup_parse_float - parse a floating number
+ * @input: input string
+ * @dec_shift: number of decimal digits to shift
+ * @v: output
+ *
+ * Parse a decimal floating point number in @input and store the result in
+ * @v with decimal point right shifted @dec_shift times.  For example, if
+ * @input is "12.3456" and @dec_shift is 3, *@v will be set to 12345.
+ * Returns 0 on success, -errno otherwise.
+ *
+ * There's nothing cgroup specific about this function except that it's
+ * currently the only user.
+ */
+int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v)
+{
+	s64 whole, frac = 0;
+	int fstart = 0, fend = 0, flen;
+
+	if (!sscanf(input, "%lld.%n%lld%n", &whole, &fstart, &frac, &fend))
+		return -EINVAL;
+	if (frac < 0)
+		return -EINVAL;
+
+	flen = fend > fstart ? fend - fstart : 0;
+	if (flen < dec_shift)
+		frac *= power_of_ten(dec_shift - flen);
+	else
+		frac = DIV_ROUND_CLOSEST_ULL(frac, power_of_ten(flen - dec_shift));
+
+	*v = whole * power_of_ten(dec_shift) + frac;
+	return 0;
+}
+
+/*
+ * sock->sk_cgrp_data handling.  For more info, see sock_cgroup_data
+ * definition in cgroup-defs.h.
+ */
+#ifdef CONFIG_SOCK_CGROUP_DATA
+
+void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
+{
+	struct cgroup *cgroup;
+
+	rcu_read_lock();
+	/* Don't associate the sock with unrelated interrupted task's cgroup. */
+	if (in_interrupt()) {
+		cgroup = &cgrp_dfl_root.cgrp;
+		cgroup_get(cgroup);
+		goto out;
+	}
+
+	while (true) {
+		struct css_set *cset;
+
+		cset = task_css_set(current);
+		if (likely(cgroup_tryget(cset->dfl_cgrp))) {
+			cgroup = cset->dfl_cgrp;
+			break;
+		}
+		cpu_relax();
+	}
+out:
+	skcd->cgroup = cgroup;
+	cgroup_bpf_get(cgroup);
+	rcu_read_unlock();
+}
+
+void cgroup_sk_clone(struct sock_cgroup_data *skcd)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(skcd);
+
+	/*
+	 * We might be cloning a socket which is left in an empty
+	 * cgroup and the cgroup might have already been rmdir'd.
+	 * Don't use cgroup_get_live().
+	 */
+	cgroup_get(cgrp);
+	cgroup_bpf_get(cgrp);
+}
+
+void cgroup_sk_free(struct sock_cgroup_data *skcd)
+{
+	struct cgroup *cgrp = sock_cgroup_ptr(skcd);
+
+	cgroup_bpf_put(cgrp);
+	cgroup_put(cgrp);
+}
+
+#endif	/* CONFIG_SOCK_CGROUP_DATA */
+
+#ifdef CONFIG_SYSFS
+static ssize_t show_delegatable_files(struct cftype *files, char *buf,
+				      ssize_t size, const char *prefix)
+{
+	struct cftype *cft;
+	ssize_t ret = 0;
+
+	for (cft = files; cft && cft->name[0] != '\0'; cft++) {
+		if (!(cft->flags & CFTYPE_NS_DELEGATABLE))
+			continue;
+
+		if (prefix)
+			ret += snprintf(buf + ret, size - ret, "%s.", prefix);
+
+		ret += snprintf(buf + ret, size - ret, "%s\n", cft->name);
+
+		if (WARN_ON(ret >= size))
+			break;
+	}
+
+	return ret;
+}
+
+static ssize_t delegate_show(struct kobject *kobj, struct kobj_attribute *attr,
+			      char *buf)
+{
+	struct cgroup_subsys *ss;
+	int ssid;
+	ssize_t ret = 0;
+
+	ret = show_delegatable_files(cgroup_base_files, buf + ret,
+				     PAGE_SIZE - ret, NULL);
+	if (cgroup_psi_enabled())
+		ret += show_delegatable_files(cgroup_psi_files, buf + ret,
+					      PAGE_SIZE - ret, NULL);
+
+	for_each_subsys(ss, ssid)
+		ret += show_delegatable_files(ss->dfl_cftypes, buf + ret,
+					      PAGE_SIZE - ret,
+					      cgroup_subsys_name[ssid]);
+
+	return ret;
+}
+static struct kobj_attribute cgroup_delegate_attr = __ATTR_RO(delegate);
+
+static ssize_t features_show(struct kobject *kobj, struct kobj_attribute *attr,
+			     char *buf)
+{
+	return snprintf(buf, PAGE_SIZE,
+			"nsdelegate\n"
+			"favordynmods\n"
+			"memory_localevents\n"
+			"memory_recursiveprot\n");
+}
+static struct kobj_attribute cgroup_features_attr = __ATTR_RO(features);
+
+static struct attribute *cgroup_sysfs_attrs[] = {
+	&cgroup_delegate_attr.attr,
+	&cgroup_features_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group cgroup_sysfs_attr_group = {
+	.attrs = cgroup_sysfs_attrs,
+	.name = "cgroup",
+};
+
+static int __init cgroup_sysfs_init(void)
+{
+	return sysfs_create_group(kernel_kobj, &cgroup_sysfs_attr_group);
+}
+subsys_initcall(cgroup_sysfs_init);
+
+#endif /* CONFIG_SYSFS */
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
new file mode 100644
index 000000000..79e6a5d4c
--- /dev/null
+++ b/kernel/cgroup/cpuset.c
@@ -0,0 +1,4241 @@
+/*
+ *  kernel/cpuset.c
+ *
+ *  Processor and Memory placement constraints for sets of tasks.
+ *
+ *  Copyright (C) 2003 BULL SA.
+ *  Copyright (C) 2004-2007 Silicon Graphics, Inc.
+ *  Copyright (C) 2006 Google, Inc
+ *
+ *  Portions derived from Patrick Mochel's sysfs code.
+ *  sysfs is Copyright (c) 2001-3 Patrick Mochel
+ *
+ *  2003-10-10 Written by Simon Derr.
+ *  2003-10-22 Updates by Stephen Hemminger.
+ *  2004 May-July Rework by Paul Jackson.
+ *  2006 Rework by Paul Menage to use generic cgroups
+ *  2008 Rework of the scheduler domains and CPU hotplug handling
+ *       by Max Krasnyansky
+ *
+ *  This file is subject to the terms and conditions of the GNU General Public
+ *  License.  See the file COPYING in the main directory of the Linux
+ *  distribution for more details.
+ */
+
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/cpuset.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/kthread.h>
+#include <linux/list.h>
+#include <linux/mempolicy.h>
+#include <linux/mm.h>
+#include <linux/memory.h>
+#include <linux/export.h>
+#include <linux/mount.h>
+#include <linux/fs_context.h>
+#include <linux/namei.h>
+#include <linux/pagemap.h>
+#include <linux/proc_fs.h>
+#include <linux/rcupdate.h>
+#include <linux/sched.h>
+#include <linux/sched/deadline.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/task.h>
+#include <linux/seq_file.h>
+#include <linux/security.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/time.h>
+#include <linux/time64.h>
+#include <linux/backing-dev.h>
+#include <linux/sort.h>
+#include <linux/oom.h>
+#include <linux/sched/isolation.h>
+#include <linux/uaccess.h>
+#include <linux/atomic.h>
+#include <linux/mutex.h>
+#include <linux/cgroup.h>
+#include <linux/wait.h>
+
+DEFINE_STATIC_KEY_FALSE(cpusets_pre_enable_key);
+DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key);
+
+/*
+ * There could be abnormal cpuset configurations for cpu or memory
+ * node binding, add this key to provide a quick low-cost judgment
+ * of the situation.
+ */
+DEFINE_STATIC_KEY_FALSE(cpusets_insane_config_key);
+
+/* See "Frequency meter" comments, below. */
+
+struct fmeter {
+	int cnt;		/* unprocessed events count */
+	int val;		/* most recent output value */
+	time64_t time;		/* clock (secs) when val computed */
+	spinlock_t lock;	/* guards read or write of above */
+};
+
+/*
+ * Invalid partition error code
+ */
+enum prs_errcode {
+	PERR_NONE = 0,
+	PERR_INVCPUS,
+	PERR_INVPARENT,
+	PERR_NOTPART,
+	PERR_NOTEXCL,
+	PERR_NOCPUS,
+	PERR_HOTPLUG,
+	PERR_CPUSEMPTY,
+};
+
+static const char * const perr_strings[] = {
+	[PERR_INVCPUS]   = "Invalid cpu list in cpuset.cpus",
+	[PERR_INVPARENT] = "Parent is an invalid partition root",
+	[PERR_NOTPART]   = "Parent is not a partition root",
+	[PERR_NOTEXCL]   = "Cpu list in cpuset.cpus not exclusive",
+	[PERR_NOCPUS]    = "Parent unable to distribute cpu downstream",
+	[PERR_HOTPLUG]   = "No cpu available due to hotplug",
+	[PERR_CPUSEMPTY] = "cpuset.cpus is empty",
+};
+
+struct cpuset {
+	struct cgroup_subsys_state css;
+
+	unsigned long flags;		/* "unsigned long" so bitops work */
+
+	/*
+	 * On default hierarchy:
+	 *
+	 * The user-configured masks can only be changed by writing to
+	 * cpuset.cpus and cpuset.mems, and won't be limited by the
+	 * parent masks.
+	 *
+	 * The effective masks is the real masks that apply to the tasks
+	 * in the cpuset. They may be changed if the configured masks are
+	 * changed or hotplug happens.
+	 *
+	 * effective_mask == configured_mask & parent's effective_mask,
+	 * and if it ends up empty, it will inherit the parent's mask.
+	 *
+	 *
+	 * On legacy hierarchy:
+	 *
+	 * The user-configured masks are always the same with effective masks.
+	 */
+
+	/* user-configured CPUs and Memory Nodes allow to tasks */
+	cpumask_var_t cpus_allowed;
+	nodemask_t mems_allowed;
+
+	/* effective CPUs and Memory Nodes allow to tasks */
+	cpumask_var_t effective_cpus;
+	nodemask_t effective_mems;
+
+	/*
+	 * CPUs allocated to child sub-partitions (default hierarchy only)
+	 * - CPUs granted by the parent = effective_cpus U subparts_cpus
+	 * - effective_cpus and subparts_cpus are mutually exclusive.
+	 *
+	 * effective_cpus contains only onlined CPUs, but subparts_cpus
+	 * may have offlined ones.
+	 */
+	cpumask_var_t subparts_cpus;
+
+	/*
+	 * This is old Memory Nodes tasks took on.
+	 *
+	 * - top_cpuset.old_mems_allowed is initialized to mems_allowed.
+	 * - A new cpuset's old_mems_allowed is initialized when some
+	 *   task is moved into it.
+	 * - old_mems_allowed is used in cpuset_migrate_mm() when we change
+	 *   cpuset.mems_allowed and have tasks' nodemask updated, and
+	 *   then old_mems_allowed is updated to mems_allowed.
+	 */
+	nodemask_t old_mems_allowed;
+
+	struct fmeter fmeter;		/* memory_pressure filter */
+
+	/*
+	 * Tasks are being attached to this cpuset.  Used to prevent
+	 * zeroing cpus/mems_allowed between ->can_attach() and ->attach().
+	 */
+	int attach_in_progress;
+
+	/* partition number for rebuild_sched_domains() */
+	int pn;
+
+	/* for custom sched domain */
+	int relax_domain_level;
+
+	/* number of CPUs in subparts_cpus */
+	int nr_subparts_cpus;
+
+	/* partition root state */
+	int partition_root_state;
+
+	/*
+	 * Default hierarchy only:
+	 * use_parent_ecpus - set if using parent's effective_cpus
+	 * child_ecpus_count - # of children with use_parent_ecpus set
+	 */
+	int use_parent_ecpus;
+	int child_ecpus_count;
+
+	/*
+	 * number of SCHED_DEADLINE tasks attached to this cpuset, so that we
+	 * know when to rebuild associated root domain bandwidth information.
+	 */
+	int nr_deadline_tasks;
+	int nr_migrate_dl_tasks;
+	u64 sum_migrate_dl_bw;
+
+	/* Invalid partition error code, not lock protected */
+	enum prs_errcode prs_err;
+
+	/* Handle for cpuset.cpus.partition */
+	struct cgroup_file partition_file;
+};
+
+/*
+ * Partition root states:
+ *
+ *   0 - member (not a partition root)
+ *   1 - partition root
+ *   2 - partition root without load balancing (isolated)
+ *  -1 - invalid partition root
+ *  -2 - invalid isolated partition root
+ */
+#define PRS_MEMBER		0
+#define PRS_ROOT		1
+#define PRS_ISOLATED		2
+#define PRS_INVALID_ROOT	-1
+#define PRS_INVALID_ISOLATED	-2
+
+static inline bool is_prs_invalid(int prs_state)
+{
+	return prs_state < 0;
+}
+
+/*
+ * Temporary cpumasks for working with partitions that are passed among
+ * functions to avoid memory allocation in inner functions.
+ */
+struct tmpmasks {
+	cpumask_var_t addmask, delmask;	/* For partition root */
+	cpumask_var_t new_cpus;		/* For update_cpumasks_hier() */
+};
+
+static inline struct cpuset *css_cs(struct cgroup_subsys_state *css)
+{
+	return css ? container_of(css, struct cpuset, css) : NULL;
+}
+
+/* Retrieve the cpuset for a task */
+static inline struct cpuset *task_cs(struct task_struct *task)
+{
+	return css_cs(task_css(task, cpuset_cgrp_id));
+}
+
+static inline struct cpuset *parent_cs(struct cpuset *cs)
+{
+	return css_cs(cs->css.parent);
+}
+
+void inc_dl_tasks_cs(struct task_struct *p)
+{
+	struct cpuset *cs = task_cs(p);
+
+	cs->nr_deadline_tasks++;
+}
+
+void dec_dl_tasks_cs(struct task_struct *p)
+{
+	struct cpuset *cs = task_cs(p);
+
+	cs->nr_deadline_tasks--;
+}
+
+/* bits in struct cpuset flags field */
+typedef enum {
+	CS_ONLINE,
+	CS_CPU_EXCLUSIVE,
+	CS_MEM_EXCLUSIVE,
+	CS_MEM_HARDWALL,
+	CS_MEMORY_MIGRATE,
+	CS_SCHED_LOAD_BALANCE,
+	CS_SPREAD_PAGE,
+	CS_SPREAD_SLAB,
+} cpuset_flagbits_t;
+
+/* convenient tests for these bits */
+static inline bool is_cpuset_online(struct cpuset *cs)
+{
+	return test_bit(CS_ONLINE, &cs->flags) && !css_is_dying(&cs->css);
+}
+
+static inline int is_cpu_exclusive(const struct cpuset *cs)
+{
+	return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
+}
+
+static inline int is_mem_exclusive(const struct cpuset *cs)
+{
+	return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
+}
+
+static inline int is_mem_hardwall(const struct cpuset *cs)
+{
+	return test_bit(CS_MEM_HARDWALL, &cs->flags);
+}
+
+static inline int is_sched_load_balance(const struct cpuset *cs)
+{
+	return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
+}
+
+static inline int is_memory_migrate(const struct cpuset *cs)
+{
+	return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
+}
+
+static inline int is_spread_page(const struct cpuset *cs)
+{
+	return test_bit(CS_SPREAD_PAGE, &cs->flags);
+}
+
+static inline int is_spread_slab(const struct cpuset *cs)
+{
+	return test_bit(CS_SPREAD_SLAB, &cs->flags);
+}
+
+static inline int is_partition_valid(const struct cpuset *cs)
+{
+	return cs->partition_root_state > 0;
+}
+
+static inline int is_partition_invalid(const struct cpuset *cs)
+{
+	return cs->partition_root_state < 0;
+}
+
+/*
+ * Callers should hold callback_lock to modify partition_root_state.
+ */
+static inline void make_partition_invalid(struct cpuset *cs)
+{
+	if (is_partition_valid(cs))
+		cs->partition_root_state = -cs->partition_root_state;
+}
+
+/*
+ * Send notification event of whenever partition_root_state changes.
+ */
+static inline void notify_partition_change(struct cpuset *cs, int old_prs)
+{
+	if (old_prs == cs->partition_root_state)
+		return;
+	cgroup_file_notify(&cs->partition_file);
+
+	/* Reset prs_err if not invalid */
+	if (is_partition_valid(cs))
+		WRITE_ONCE(cs->prs_err, PERR_NONE);
+}
+
+static struct cpuset top_cpuset = {
+	.flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) |
+		  (1 << CS_MEM_EXCLUSIVE)),
+	.partition_root_state = PRS_ROOT,
+};
+
+/**
+ * cpuset_for_each_child - traverse online children of a cpuset
+ * @child_cs: loop cursor pointing to the current child
+ * @pos_css: used for iteration
+ * @parent_cs: target cpuset to walk children of
+ *
+ * Walk @child_cs through the online children of @parent_cs.  Must be used
+ * with RCU read locked.
+ */
+#define cpuset_for_each_child(child_cs, pos_css, parent_cs)		\
+	css_for_each_child((pos_css), &(parent_cs)->css)		\
+		if (is_cpuset_online(((child_cs) = css_cs((pos_css)))))
+
+/**
+ * cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants
+ * @des_cs: loop cursor pointing to the current descendant
+ * @pos_css: used for iteration
+ * @root_cs: target cpuset to walk ancestor of
+ *
+ * Walk @des_cs through the online descendants of @root_cs.  Must be used
+ * with RCU read locked.  The caller may modify @pos_css by calling
+ * css_rightmost_descendant() to skip subtree.  @root_cs is included in the
+ * iteration and the first node to be visited.
+ */
+#define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs)	\
+	css_for_each_descendant_pre((pos_css), &(root_cs)->css)		\
+		if (is_cpuset_online(((des_cs) = css_cs((pos_css)))))
+
+/*
+ * There are two global locks guarding cpuset structures - cpuset_mutex and
+ * callback_lock. We also require taking task_lock() when dereferencing a
+ * task's cpuset pointer. See "The task_lock() exception", at the end of this
+ * comment.  The cpuset code uses only cpuset_mutex. Other kernel subsystems
+ * can use cpuset_lock()/cpuset_unlock() to prevent change to cpuset
+ * structures. Note that cpuset_mutex needs to be a mutex as it is used in
+ * paths that rely on priority inheritance (e.g. scheduler - on RT) for
+ * correctness.
+ *
+ * A task must hold both locks to modify cpusets.  If a task holds
+ * cpuset_mutex, it blocks others, ensuring that it is the only task able to
+ * also acquire callback_lock and be able to modify cpusets.  It can perform
+ * various checks on the cpuset structure first, knowing nothing will change.
+ * It can also allocate memory while just holding cpuset_mutex.  While it is
+ * performing these checks, various callback routines can briefly acquire
+ * callback_lock to query cpusets.  Once it is ready to make the changes, it
+ * takes callback_lock, blocking everyone else.
+ *
+ * Calls to the kernel memory allocator can not be made while holding
+ * callback_lock, as that would risk double tripping on callback_lock
+ * from one of the callbacks into the cpuset code from within
+ * __alloc_pages().
+ *
+ * If a task is only holding callback_lock, then it has read-only
+ * access to cpusets.
+ *
+ * Now, the task_struct fields mems_allowed and mempolicy may be changed
+ * by other task, we use alloc_lock in the task_struct fields to protect
+ * them.
+ *
+ * The cpuset_common_file_read() handlers only hold callback_lock across
+ * small pieces of code, such as when reading out possibly multi-word
+ * cpumasks and nodemasks.
+ *
+ * Accessing a task's cpuset should be done in accordance with the
+ * guidelines for accessing subsystem state in kernel/cgroup.c
+ */
+
+static DEFINE_MUTEX(cpuset_mutex);
+
+void cpuset_lock(void)
+{
+	mutex_lock(&cpuset_mutex);
+}
+
+void cpuset_unlock(void)
+{
+	mutex_unlock(&cpuset_mutex);
+}
+
+static DEFINE_SPINLOCK(callback_lock);
+
+static struct workqueue_struct *cpuset_migrate_mm_wq;
+
+/*
+ * CPU / memory hotplug is handled asynchronously.
+ */
+static void cpuset_hotplug_workfn(struct work_struct *work);
+static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn);
+
+static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq);
+
+static inline void check_insane_mems_config(nodemask_t *nodes)
+{
+	if (!cpusets_insane_config() &&
+		movable_only_nodes(nodes)) {
+		static_branch_enable(&cpusets_insane_config_key);
+		pr_info("Unsupported (movable nodes only) cpuset configuration detected (nmask=%*pbl)!\n"
+			"Cpuset allocations might fail even with a lot of memory available.\n",
+			nodemask_pr_args(nodes));
+	}
+}
+
+/*
+ * Cgroup v2 behavior is used on the "cpus" and "mems" control files when
+ * on default hierarchy or when the cpuset_v2_mode flag is set by mounting
+ * the v1 cpuset cgroup filesystem with the "cpuset_v2_mode" mount option.
+ * With v2 behavior, "cpus" and "mems" are always what the users have
+ * requested and won't be changed by hotplug events. Only the effective
+ * cpus or mems will be affected.
+ */
+static inline bool is_in_v2_mode(void)
+{
+	return cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
+	      (cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE);
+}
+
+/**
+ * partition_is_populated - check if partition has tasks
+ * @cs: partition root to be checked
+ * @excluded_child: a child cpuset to be excluded in task checking
+ * Return: true if there are tasks, false otherwise
+ *
+ * It is assumed that @cs is a valid partition root. @excluded_child should
+ * be non-NULL when this cpuset is going to become a partition itself.
+ */
+static inline bool partition_is_populated(struct cpuset *cs,
+					  struct cpuset *excluded_child)
+{
+	struct cgroup_subsys_state *css;
+	struct cpuset *child;
+
+	if (cs->css.cgroup->nr_populated_csets)
+		return true;
+	if (!excluded_child && !cs->nr_subparts_cpus)
+		return cgroup_is_populated(cs->css.cgroup);
+
+	rcu_read_lock();
+	cpuset_for_each_child(child, css, cs) {
+		if (child == excluded_child)
+			continue;
+		if (is_partition_valid(child))
+			continue;
+		if (cgroup_is_populated(child->css.cgroup)) {
+			rcu_read_unlock();
+			return true;
+		}
+	}
+	rcu_read_unlock();
+	return false;
+}
+
+/*
+ * Return in pmask the portion of a task's cpusets's cpus_allowed that
+ * are online and are capable of running the task.  If none are found,
+ * walk up the cpuset hierarchy until we find one that does have some
+ * appropriate cpus.
+ *
+ * One way or another, we guarantee to return some non-empty subset
+ * of cpu_online_mask.
+ *
+ * Call with callback_lock or cpuset_mutex held.
+ */
+static void guarantee_online_cpus(struct task_struct *tsk,
+				  struct cpumask *pmask)
+{
+	const struct cpumask *possible_mask = task_cpu_possible_mask(tsk);
+	struct cpuset *cs;
+
+	if (WARN_ON(!cpumask_and(pmask, possible_mask, cpu_online_mask)))
+		cpumask_copy(pmask, cpu_online_mask);
+
+	rcu_read_lock();
+	cs = task_cs(tsk);
+
+	while (!cpumask_intersects(cs->effective_cpus, pmask)) {
+		cs = parent_cs(cs);
+		if (unlikely(!cs)) {
+			/*
+			 * The top cpuset doesn't have any online cpu as a
+			 * consequence of a race between cpuset_hotplug_work
+			 * and cpu hotplug notifier.  But we know the top
+			 * cpuset's effective_cpus is on its way to be
+			 * identical to cpu_online_mask.
+			 */
+			goto out_unlock;
+		}
+	}
+	cpumask_and(pmask, pmask, cs->effective_cpus);
+
+out_unlock:
+	rcu_read_unlock();
+}
+
+/*
+ * Return in *pmask the portion of a cpusets's mems_allowed that
+ * are online, with memory.  If none are online with memory, walk
+ * up the cpuset hierarchy until we find one that does have some
+ * online mems.  The top cpuset always has some mems online.
+ *
+ * One way or another, we guarantee to return some non-empty subset
+ * of node_states[N_MEMORY].
+ *
+ * Call with callback_lock or cpuset_mutex held.
+ */
+static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask)
+{
+	while (!nodes_intersects(cs->effective_mems, node_states[N_MEMORY]))
+		cs = parent_cs(cs);
+	nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]);
+}
+
+/*
+ * update task's spread flag if cpuset's page/slab spread flag is set
+ *
+ * Call with callback_lock or cpuset_mutex held. The check can be skipped
+ * if on default hierarchy.
+ */
+static void cpuset_update_task_spread_flags(struct cpuset *cs,
+					struct task_struct *tsk)
+{
+	if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys))
+		return;
+
+	if (is_spread_page(cs))
+		task_set_spread_page(tsk);
+	else
+		task_clear_spread_page(tsk);
+
+	if (is_spread_slab(cs))
+		task_set_spread_slab(tsk);
+	else
+		task_clear_spread_slab(tsk);
+}
+
+/*
+ * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
+ *
+ * One cpuset is a subset of another if all its allowed CPUs and
+ * Memory Nodes are a subset of the other, and its exclusive flags
+ * are only set if the other's are set.  Call holding cpuset_mutex.
+ */
+
+static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
+{
+	return	cpumask_subset(p->cpus_allowed, q->cpus_allowed) &&
+		nodes_subset(p->mems_allowed, q->mems_allowed) &&
+		is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
+		is_mem_exclusive(p) <= is_mem_exclusive(q);
+}
+
+/**
+ * alloc_cpumasks - allocate three cpumasks for cpuset
+ * @cs:  the cpuset that have cpumasks to be allocated.
+ * @tmp: the tmpmasks structure pointer
+ * Return: 0 if successful, -ENOMEM otherwise.
+ *
+ * Only one of the two input arguments should be non-NULL.
+ */
+static inline int alloc_cpumasks(struct cpuset *cs, struct tmpmasks *tmp)
+{
+	cpumask_var_t *pmask1, *pmask2, *pmask3;
+
+	if (cs) {
+		pmask1 = &cs->cpus_allowed;
+		pmask2 = &cs->effective_cpus;
+		pmask3 = &cs->subparts_cpus;
+	} else {
+		pmask1 = &tmp->new_cpus;
+		pmask2 = &tmp->addmask;
+		pmask3 = &tmp->delmask;
+	}
+
+	if (!zalloc_cpumask_var(pmask1, GFP_KERNEL))
+		return -ENOMEM;
+
+	if (!zalloc_cpumask_var(pmask2, GFP_KERNEL))
+		goto free_one;
+
+	if (!zalloc_cpumask_var(pmask3, GFP_KERNEL))
+		goto free_two;
+
+	return 0;
+
+free_two:
+	free_cpumask_var(*pmask2);
+free_one:
+	free_cpumask_var(*pmask1);
+	return -ENOMEM;
+}
+
+/**
+ * free_cpumasks - free cpumasks in a tmpmasks structure
+ * @cs:  the cpuset that have cpumasks to be free.
+ * @tmp: the tmpmasks structure pointer
+ */
+static inline void free_cpumasks(struct cpuset *cs, struct tmpmasks *tmp)
+{
+	if (cs) {
+		free_cpumask_var(cs->cpus_allowed);
+		free_cpumask_var(cs->effective_cpus);
+		free_cpumask_var(cs->subparts_cpus);
+	}
+	if (tmp) {
+		free_cpumask_var(tmp->new_cpus);
+		free_cpumask_var(tmp->addmask);
+		free_cpumask_var(tmp->delmask);
+	}
+}
+
+/**
+ * alloc_trial_cpuset - allocate a trial cpuset
+ * @cs: the cpuset that the trial cpuset duplicates
+ */
+static struct cpuset *alloc_trial_cpuset(struct cpuset *cs)
+{
+	struct cpuset *trial;
+
+	trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL);
+	if (!trial)
+		return NULL;
+
+	if (alloc_cpumasks(trial, NULL)) {
+		kfree(trial);
+		return NULL;
+	}
+
+	cpumask_copy(trial->cpus_allowed, cs->cpus_allowed);
+	cpumask_copy(trial->effective_cpus, cs->effective_cpus);
+	return trial;
+}
+
+/**
+ * free_cpuset - free the cpuset
+ * @cs: the cpuset to be freed
+ */
+static inline void free_cpuset(struct cpuset *cs)
+{
+	free_cpumasks(cs, NULL);
+	kfree(cs);
+}
+
+/*
+ * validate_change_legacy() - Validate conditions specific to legacy (v1)
+ *                            behavior.
+ */
+static int validate_change_legacy(struct cpuset *cur, struct cpuset *trial)
+{
+	struct cgroup_subsys_state *css;
+	struct cpuset *c, *par;
+	int ret;
+
+	WARN_ON_ONCE(!rcu_read_lock_held());
+
+	/* Each of our child cpusets must be a subset of us */
+	ret = -EBUSY;
+	cpuset_for_each_child(c, css, cur)
+		if (!is_cpuset_subset(c, trial))
+			goto out;
+
+	/* On legacy hierarchy, we must be a subset of our parent cpuset. */
+	ret = -EACCES;
+	par = parent_cs(cur);
+	if (par && !is_cpuset_subset(trial, par))
+		goto out;
+
+	ret = 0;
+out:
+	return ret;
+}
+
+/*
+ * validate_change() - Used to validate that any proposed cpuset change
+ *		       follows the structural rules for cpusets.
+ *
+ * If we replaced the flag and mask values of the current cpuset
+ * (cur) with those values in the trial cpuset (trial), would
+ * our various subset and exclusive rules still be valid?  Presumes
+ * cpuset_mutex held.
+ *
+ * 'cur' is the address of an actual, in-use cpuset.  Operations
+ * such as list traversal that depend on the actual address of the
+ * cpuset in the list must use cur below, not trial.
+ *
+ * 'trial' is the address of bulk structure copy of cur, with
+ * perhaps one or more of the fields cpus_allowed, mems_allowed,
+ * or flags changed to new, trial values.
+ *
+ * Return 0 if valid, -errno if not.
+ */
+
+static int validate_change(struct cpuset *cur, struct cpuset *trial)
+{
+	struct cgroup_subsys_state *css;
+	struct cpuset *c, *par;
+	int ret = 0;
+
+	rcu_read_lock();
+
+	if (!is_in_v2_mode())
+		ret = validate_change_legacy(cur, trial);
+	if (ret)
+		goto out;
+
+	/* Remaining checks don't apply to root cpuset */
+	if (cur == &top_cpuset)
+		goto out;
+
+	par = parent_cs(cur);
+
+	/*
+	 * Cpusets with tasks - existing or newly being attached - can't
+	 * be changed to have empty cpus_allowed or mems_allowed.
+	 */
+	ret = -ENOSPC;
+	if ((cgroup_is_populated(cur->css.cgroup) || cur->attach_in_progress)) {
+		if (!cpumask_empty(cur->cpus_allowed) &&
+		    cpumask_empty(trial->cpus_allowed))
+			goto out;
+		if (!nodes_empty(cur->mems_allowed) &&
+		    nodes_empty(trial->mems_allowed))
+			goto out;
+	}
+
+	/*
+	 * We can't shrink if we won't have enough room for SCHED_DEADLINE
+	 * tasks.
+	 */
+	ret = -EBUSY;
+	if (is_cpu_exclusive(cur) &&
+	    !cpuset_cpumask_can_shrink(cur->cpus_allowed,
+				       trial->cpus_allowed))
+		goto out;
+
+	/*
+	 * If either I or some sibling (!= me) is exclusive, we can't
+	 * overlap
+	 */
+	ret = -EINVAL;
+	cpuset_for_each_child(c, css, par) {
+		if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
+		    c != cur &&
+		    cpumask_intersects(trial->cpus_allowed, c->cpus_allowed))
+			goto out;
+		if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
+		    c != cur &&
+		    nodes_intersects(trial->mems_allowed, c->mems_allowed))
+			goto out;
+	}
+
+	ret = 0;
+out:
+	rcu_read_unlock();
+	return ret;
+}
+
+#ifdef CONFIG_SMP
+/*
+ * Helper routine for generate_sched_domains().
+ * Do cpusets a, b have overlapping effective cpus_allowed masks?
+ */
+static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
+{
+	return cpumask_intersects(a->effective_cpus, b->effective_cpus);
+}
+
+static void
+update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)
+{
+	if (dattr->relax_domain_level < c->relax_domain_level)
+		dattr->relax_domain_level = c->relax_domain_level;
+	return;
+}
+
+static void update_domain_attr_tree(struct sched_domain_attr *dattr,
+				    struct cpuset *root_cs)
+{
+	struct cpuset *cp;
+	struct cgroup_subsys_state *pos_css;
+
+	rcu_read_lock();
+	cpuset_for_each_descendant_pre(cp, pos_css, root_cs) {
+		/* skip the whole subtree if @cp doesn't have any CPU */
+		if (cpumask_empty(cp->cpus_allowed)) {
+			pos_css = css_rightmost_descendant(pos_css);
+			continue;
+		}
+
+		if (is_sched_load_balance(cp))
+			update_domain_attr(dattr, cp);
+	}
+	rcu_read_unlock();
+}
+
+/* Must be called with cpuset_mutex held.  */
+static inline int nr_cpusets(void)
+{
+	/* jump label reference count + the top-level cpuset */
+	return static_key_count(&cpusets_enabled_key.key) + 1;
+}
+
+/*
+ * generate_sched_domains()
+ *
+ * This function builds a partial partition of the systems CPUs
+ * A 'partial partition' is a set of non-overlapping subsets whose
+ * union is a subset of that set.
+ * The output of this function needs to be passed to kernel/sched/core.c
+ * partition_sched_domains() routine, which will rebuild the scheduler's
+ * load balancing domains (sched domains) as specified by that partial
+ * partition.
+ *
+ * See "What is sched_load_balance" in Documentation/admin-guide/cgroup-v1/cpusets.rst
+ * for a background explanation of this.
+ *
+ * Does not return errors, on the theory that the callers of this
+ * routine would rather not worry about failures to rebuild sched
+ * domains when operating in the severe memory shortage situations
+ * that could cause allocation failures below.
+ *
+ * Must be called with cpuset_mutex held.
+ *
+ * The three key local variables below are:
+ *    cp - cpuset pointer, used (together with pos_css) to perform a
+ *	   top-down scan of all cpusets. For our purposes, rebuilding
+ *	   the schedulers sched domains, we can ignore !is_sched_load_
+ *	   balance cpusets.
+ *  csa  - (for CpuSet Array) Array of pointers to all the cpusets
+ *	   that need to be load balanced, for convenient iterative
+ *	   access by the subsequent code that finds the best partition,
+ *	   i.e the set of domains (subsets) of CPUs such that the
+ *	   cpus_allowed of every cpuset marked is_sched_load_balance
+ *	   is a subset of one of these domains, while there are as
+ *	   many such domains as possible, each as small as possible.
+ * doms  - Conversion of 'csa' to an array of cpumasks, for passing to
+ *	   the kernel/sched/core.c routine partition_sched_domains() in a
+ *	   convenient format, that can be easily compared to the prior
+ *	   value to determine what partition elements (sched domains)
+ *	   were changed (added or removed.)
+ *
+ * Finding the best partition (set of domains):
+ *	The triple nested loops below over i, j, k scan over the
+ *	load balanced cpusets (using the array of cpuset pointers in
+ *	csa[]) looking for pairs of cpusets that have overlapping
+ *	cpus_allowed, but which don't have the same 'pn' partition
+ *	number and gives them in the same partition number.  It keeps
+ *	looping on the 'restart' label until it can no longer find
+ *	any such pairs.
+ *
+ *	The union of the cpus_allowed masks from the set of
+ *	all cpusets having the same 'pn' value then form the one
+ *	element of the partition (one sched domain) to be passed to
+ *	partition_sched_domains().
+ */
+static int generate_sched_domains(cpumask_var_t **domains,
+			struct sched_domain_attr **attributes)
+{
+	struct cpuset *cp;	/* top-down scan of cpusets */
+	struct cpuset **csa;	/* array of all cpuset ptrs */
+	int csn;		/* how many cpuset ptrs in csa so far */
+	int i, j, k;		/* indices for partition finding loops */
+	cpumask_var_t *doms;	/* resulting partition; i.e. sched domains */
+	struct sched_domain_attr *dattr;  /* attributes for custom domains */
+	int ndoms = 0;		/* number of sched domains in result */
+	int nslot;		/* next empty doms[] struct cpumask slot */
+	struct cgroup_subsys_state *pos_css;
+	bool root_load_balance = is_sched_load_balance(&top_cpuset);
+
+	doms = NULL;
+	dattr = NULL;
+	csa = NULL;
+
+	/* Special case for the 99% of systems with one, full, sched domain */
+	if (root_load_balance && !top_cpuset.nr_subparts_cpus) {
+		ndoms = 1;
+		doms = alloc_sched_domains(ndoms);
+		if (!doms)
+			goto done;
+
+		dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL);
+		if (dattr) {
+			*dattr = SD_ATTR_INIT;
+			update_domain_attr_tree(dattr, &top_cpuset);
+		}
+		cpumask_and(doms[0], top_cpuset.effective_cpus,
+			    housekeeping_cpumask(HK_TYPE_DOMAIN));
+
+		goto done;
+	}
+
+	csa = kmalloc_array(nr_cpusets(), sizeof(cp), GFP_KERNEL);
+	if (!csa)
+		goto done;
+	csn = 0;
+
+	rcu_read_lock();
+	if (root_load_balance)
+		csa[csn++] = &top_cpuset;
+	cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) {
+		if (cp == &top_cpuset)
+			continue;
+		/*
+		 * Continue traversing beyond @cp iff @cp has some CPUs and
+		 * isn't load balancing.  The former is obvious.  The
+		 * latter: All child cpusets contain a subset of the
+		 * parent's cpus, so just skip them, and then we call
+		 * update_domain_attr_tree() to calc relax_domain_level of
+		 * the corresponding sched domain.
+		 *
+		 * If root is load-balancing, we can skip @cp if it
+		 * is a subset of the root's effective_cpus.
+		 */
+		if (!cpumask_empty(cp->cpus_allowed) &&
+		    !(is_sched_load_balance(cp) &&
+		      cpumask_intersects(cp->cpus_allowed,
+					 housekeeping_cpumask(HK_TYPE_DOMAIN))))
+			continue;
+
+		if (root_load_balance &&
+		    cpumask_subset(cp->cpus_allowed, top_cpuset.effective_cpus))
+			continue;
+
+		if (is_sched_load_balance(cp) &&
+		    !cpumask_empty(cp->effective_cpus))
+			csa[csn++] = cp;
+
+		/* skip @cp's subtree if not a partition root */
+		if (!is_partition_valid(cp))
+			pos_css = css_rightmost_descendant(pos_css);
+	}
+	rcu_read_unlock();
+
+	for (i = 0; i < csn; i++)
+		csa[i]->pn = i;
+	ndoms = csn;
+
+restart:
+	/* Find the best partition (set of sched domains) */
+	for (i = 0; i < csn; i++) {
+		struct cpuset *a = csa[i];
+		int apn = a->pn;
+
+		for (j = 0; j < csn; j++) {
+			struct cpuset *b = csa[j];
+			int bpn = b->pn;
+
+			if (apn != bpn && cpusets_overlap(a, b)) {
+				for (k = 0; k < csn; k++) {
+					struct cpuset *c = csa[k];
+
+					if (c->pn == bpn)
+						c->pn = apn;
+				}
+				ndoms--;	/* one less element */
+				goto restart;
+			}
+		}
+	}
+
+	/*
+	 * Now we know how many domains to create.
+	 * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
+	 */
+	doms = alloc_sched_domains(ndoms);
+	if (!doms)
+		goto done;
+
+	/*
+	 * The rest of the code, including the scheduler, can deal with
+	 * dattr==NULL case. No need to abort if alloc fails.
+	 */
+	dattr = kmalloc_array(ndoms, sizeof(struct sched_domain_attr),
+			      GFP_KERNEL);
+
+	for (nslot = 0, i = 0; i < csn; i++) {
+		struct cpuset *a = csa[i];
+		struct cpumask *dp;
+		int apn = a->pn;
+
+		if (apn < 0) {
+			/* Skip completed partitions */
+			continue;
+		}
+
+		dp = doms[nslot];
+
+		if (nslot == ndoms) {
+			static int warnings = 10;
+			if (warnings) {
+				pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n",
+					nslot, ndoms, csn, i, apn);
+				warnings--;
+			}
+			continue;
+		}
+
+		cpumask_clear(dp);
+		if (dattr)
+			*(dattr + nslot) = SD_ATTR_INIT;
+		for (j = i; j < csn; j++) {
+			struct cpuset *b = csa[j];
+
+			if (apn == b->pn) {
+				cpumask_or(dp, dp, b->effective_cpus);
+				cpumask_and(dp, dp, housekeeping_cpumask(HK_TYPE_DOMAIN));
+				if (dattr)
+					update_domain_attr_tree(dattr + nslot, b);
+
+				/* Done with this partition */
+				b->pn = -1;
+			}
+		}
+		nslot++;
+	}
+	BUG_ON(nslot != ndoms);
+
+done:
+	kfree(csa);
+
+	/*
+	 * Fallback to the default domain if kmalloc() failed.
+	 * See comments in partition_sched_domains().
+	 */
+	if (doms == NULL)
+		ndoms = 1;
+
+	*domains    = doms;
+	*attributes = dattr;
+	return ndoms;
+}
+
+static void dl_update_tasks_root_domain(struct cpuset *cs)
+{
+	struct css_task_iter it;
+	struct task_struct *task;
+
+	if (cs->nr_deadline_tasks == 0)
+		return;
+
+	css_task_iter_start(&cs->css, 0, &it);
+
+	while ((task = css_task_iter_next(&it)))
+		dl_add_task_root_domain(task);
+
+	css_task_iter_end(&it);
+}
+
+static void dl_rebuild_rd_accounting(void)
+{
+	struct cpuset *cs = NULL;
+	struct cgroup_subsys_state *pos_css;
+
+	lockdep_assert_held(&cpuset_mutex);
+	lockdep_assert_cpus_held();
+	lockdep_assert_held(&sched_domains_mutex);
+
+	rcu_read_lock();
+
+	/*
+	 * Clear default root domain DL accounting, it will be computed again
+	 * if a task belongs to it.
+	 */
+	dl_clear_root_domain(&def_root_domain);
+
+	cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
+
+		if (cpumask_empty(cs->effective_cpus)) {
+			pos_css = css_rightmost_descendant(pos_css);
+			continue;
+		}
+
+		css_get(&cs->css);
+
+		rcu_read_unlock();
+
+		dl_update_tasks_root_domain(cs);
+
+		rcu_read_lock();
+		css_put(&cs->css);
+	}
+	rcu_read_unlock();
+}
+
+static void
+partition_and_rebuild_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+				    struct sched_domain_attr *dattr_new)
+{
+	mutex_lock(&sched_domains_mutex);
+	partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
+	dl_rebuild_rd_accounting();
+	mutex_unlock(&sched_domains_mutex);
+}
+
+/*
+ * Rebuild scheduler domains.
+ *
+ * If the flag 'sched_load_balance' of any cpuset with non-empty
+ * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
+ * which has that flag enabled, or if any cpuset with a non-empty
+ * 'cpus' is removed, then call this routine to rebuild the
+ * scheduler's dynamic sched domains.
+ *
+ * Call with cpuset_mutex held.  Takes cpus_read_lock().
+ */
+static void rebuild_sched_domains_locked(void)
+{
+	struct cgroup_subsys_state *pos_css;
+	struct sched_domain_attr *attr;
+	cpumask_var_t *doms;
+	struct cpuset *cs;
+	int ndoms;
+
+	lockdep_assert_cpus_held();
+	lockdep_assert_held(&cpuset_mutex);
+
+	/*
+	 * If we have raced with CPU hotplug, return early to avoid
+	 * passing doms with offlined cpu to partition_sched_domains().
+	 * Anyways, cpuset_hotplug_workfn() will rebuild sched domains.
+	 *
+	 * With no CPUs in any subpartitions, top_cpuset's effective CPUs
+	 * should be the same as the active CPUs, so checking only top_cpuset
+	 * is enough to detect racing CPU offlines.
+	 */
+	if (!top_cpuset.nr_subparts_cpus &&
+	    !cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
+		return;
+
+	/*
+	 * With subpartition CPUs, however, the effective CPUs of a partition
+	 * root should be only a subset of the active CPUs.  Since a CPU in any
+	 * partition root could be offlined, all must be checked.
+	 */
+	if (top_cpuset.nr_subparts_cpus) {
+		rcu_read_lock();
+		cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
+			if (!is_partition_valid(cs)) {
+				pos_css = css_rightmost_descendant(pos_css);
+				continue;
+			}
+			if (!cpumask_subset(cs->effective_cpus,
+					    cpu_active_mask)) {
+				rcu_read_unlock();
+				return;
+			}
+		}
+		rcu_read_unlock();
+	}
+
+	/* Generate domain masks and attrs */
+	ndoms = generate_sched_domains(&doms, &attr);
+
+	/* Have scheduler rebuild the domains */
+	partition_and_rebuild_sched_domains(ndoms, doms, attr);
+}
+#else /* !CONFIG_SMP */
+static void rebuild_sched_domains_locked(void)
+{
+}
+#endif /* CONFIG_SMP */
+
+void rebuild_sched_domains(void)
+{
+	cpus_read_lock();
+	mutex_lock(&cpuset_mutex);
+	rebuild_sched_domains_locked();
+	mutex_unlock(&cpuset_mutex);
+	cpus_read_unlock();
+}
+
+/**
+ * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
+ * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
+ * @new_cpus: the temp variable for the new effective_cpus mask
+ *
+ * Iterate through each task of @cs updating its cpus_allowed to the
+ * effective cpuset's.  As this function is called with cpuset_mutex held,
+ * cpuset membership stays stable.
+ */
+static void update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus)
+{
+	struct css_task_iter it;
+	struct task_struct *task;
+	bool top_cs = cs == &top_cpuset;
+
+	css_task_iter_start(&cs->css, 0, &it);
+	while ((task = css_task_iter_next(&it))) {
+		/*
+		 * Percpu kthreads in top_cpuset are ignored
+		 */
+		if (top_cs && (task->flags & PF_KTHREAD) &&
+		    kthread_is_per_cpu(task))
+			continue;
+
+		cpumask_and(new_cpus, cs->effective_cpus,
+			    task_cpu_possible_mask(task));
+		set_cpus_allowed_ptr(task, new_cpus);
+	}
+	css_task_iter_end(&it);
+}
+
+/**
+ * compute_effective_cpumask - Compute the effective cpumask of the cpuset
+ * @new_cpus: the temp variable for the new effective_cpus mask
+ * @cs: the cpuset the need to recompute the new effective_cpus mask
+ * @parent: the parent cpuset
+ *
+ * If the parent has subpartition CPUs, include them in the list of
+ * allowable CPUs in computing the new effective_cpus mask. Since offlined
+ * CPUs are not removed from subparts_cpus, we have to use cpu_active_mask
+ * to mask those out.
+ */
+static void compute_effective_cpumask(struct cpumask *new_cpus,
+				      struct cpuset *cs, struct cpuset *parent)
+{
+	if (parent->nr_subparts_cpus) {
+		cpumask_or(new_cpus, parent->effective_cpus,
+			   parent->subparts_cpus);
+		cpumask_and(new_cpus, new_cpus, cs->cpus_allowed);
+		cpumask_and(new_cpus, new_cpus, cpu_active_mask);
+	} else {
+		cpumask_and(new_cpus, cs->cpus_allowed, parent->effective_cpus);
+	}
+}
+
+/*
+ * Commands for update_parent_subparts_cpumask
+ */
+enum subparts_cmd {
+	partcmd_enable,		/* Enable partition root	 */
+	partcmd_disable,	/* Disable partition root	 */
+	partcmd_update,		/* Update parent's subparts_cpus */
+	partcmd_invalidate,	/* Make partition invalid	 */
+};
+
+static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
+		       int turning_on);
+/**
+ * update_parent_subparts_cpumask - update subparts_cpus mask of parent cpuset
+ * @cpuset:  The cpuset that requests change in partition root state
+ * @cmd:     Partition root state change command
+ * @newmask: Optional new cpumask for partcmd_update
+ * @tmp:     Temporary addmask and delmask
+ * Return:   0 or a partition root state error code
+ *
+ * For partcmd_enable, the cpuset is being transformed from a non-partition
+ * root to a partition root. The cpus_allowed mask of the given cpuset will
+ * be put into parent's subparts_cpus and taken away from parent's
+ * effective_cpus. The function will return 0 if all the CPUs listed in
+ * cpus_allowed can be granted or an error code will be returned.
+ *
+ * For partcmd_disable, the cpuset is being transformed from a partition
+ * root back to a non-partition root. Any CPUs in cpus_allowed that are in
+ * parent's subparts_cpus will be taken away from that cpumask and put back
+ * into parent's effective_cpus. 0 will always be returned.
+ *
+ * For partcmd_update, if the optional newmask is specified, the cpu list is
+ * to be changed from cpus_allowed to newmask. Otherwise, cpus_allowed is
+ * assumed to remain the same. The cpuset should either be a valid or invalid
+ * partition root. The partition root state may change from valid to invalid
+ * or vice versa. An error code will only be returned if transitioning from
+ * invalid to valid violates the exclusivity rule.
+ *
+ * For partcmd_invalidate, the current partition will be made invalid.
+ *
+ * The partcmd_enable and partcmd_disable commands are used by
+ * update_prstate(). An error code may be returned and the caller will check
+ * for error.
+ *
+ * The partcmd_update command is used by update_cpumasks_hier() with newmask
+ * NULL and update_cpumask() with newmask set. The partcmd_invalidate is used
+ * by update_cpumask() with NULL newmask. In both cases, the callers won't
+ * check for error and so partition_root_state and prs_error will be updated
+ * directly.
+ */
+static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
+					  struct cpumask *newmask,
+					  struct tmpmasks *tmp)
+{
+	struct cpuset *parent = parent_cs(cs);
+	int adding;	/* Moving cpus from effective_cpus to subparts_cpus */
+	int deleting;	/* Moving cpus from subparts_cpus to effective_cpus */
+	int old_prs, new_prs;
+	int part_error = PERR_NONE;	/* Partition error? */
+
+	lockdep_assert_held(&cpuset_mutex);
+
+	/*
+	 * The parent must be a partition root.
+	 * The new cpumask, if present, or the current cpus_allowed must
+	 * not be empty.
+	 */
+	if (!is_partition_valid(parent)) {
+		return is_partition_invalid(parent)
+		       ? PERR_INVPARENT : PERR_NOTPART;
+	}
+	if ((newmask && cpumask_empty(newmask)) ||
+	   (!newmask && cpumask_empty(cs->cpus_allowed)))
+		return PERR_CPUSEMPTY;
+
+	/*
+	 * new_prs will only be changed for the partcmd_update and
+	 * partcmd_invalidate commands.
+	 */
+	adding = deleting = false;
+	old_prs = new_prs = cs->partition_root_state;
+	if (cmd == partcmd_enable) {
+		/*
+		 * Enabling partition root is not allowed if cpus_allowed
+		 * doesn't overlap parent's cpus_allowed.
+		 */
+		if (!cpumask_intersects(cs->cpus_allowed, parent->cpus_allowed))
+			return PERR_INVCPUS;
+
+		/*
+		 * A parent can be left with no CPU as long as there is no
+		 * task directly associated with the parent partition.
+		 */
+		if (cpumask_subset(parent->effective_cpus, cs->cpus_allowed) &&
+		    partition_is_populated(parent, cs))
+			return PERR_NOCPUS;
+
+		cpumask_copy(tmp->addmask, cs->cpus_allowed);
+		adding = true;
+	} else if (cmd == partcmd_disable) {
+		/*
+		 * Need to remove cpus from parent's subparts_cpus for valid
+		 * partition root.
+		 */
+		deleting = !is_prs_invalid(old_prs) &&
+			   cpumask_and(tmp->delmask, cs->cpus_allowed,
+				       parent->subparts_cpus);
+	} else if (cmd == partcmd_invalidate) {
+		if (is_prs_invalid(old_prs))
+			return 0;
+
+		/*
+		 * Make the current partition invalid. It is assumed that
+		 * invalidation is caused by violating cpu exclusivity rule.
+		 */
+		deleting = cpumask_and(tmp->delmask, cs->cpus_allowed,
+				       parent->subparts_cpus);
+		if (old_prs > 0) {
+			new_prs = -old_prs;
+			part_error = PERR_NOTEXCL;
+		}
+	} else if (newmask) {
+		/*
+		 * partcmd_update with newmask:
+		 *
+		 * Compute add/delete mask to/from subparts_cpus
+		 *
+		 * delmask = cpus_allowed & ~newmask & parent->subparts_cpus
+		 * addmask = newmask & parent->cpus_allowed
+		 *		     & ~parent->subparts_cpus
+		 */
+		cpumask_andnot(tmp->delmask, cs->cpus_allowed, newmask);
+		deleting = cpumask_and(tmp->delmask, tmp->delmask,
+				       parent->subparts_cpus);
+
+		cpumask_and(tmp->addmask, newmask, parent->cpus_allowed);
+		adding = cpumask_andnot(tmp->addmask, tmp->addmask,
+					parent->subparts_cpus);
+		/*
+		 * Make partition invalid if parent's effective_cpus could
+		 * become empty and there are tasks in the parent.
+		 */
+		if (adding &&
+		    cpumask_subset(parent->effective_cpus, tmp->addmask) &&
+		    !cpumask_intersects(tmp->delmask, cpu_active_mask) &&
+		    partition_is_populated(parent, cs)) {
+			part_error = PERR_NOCPUS;
+			adding = false;
+			deleting = cpumask_and(tmp->delmask, cs->cpus_allowed,
+					       parent->subparts_cpus);
+		}
+	} else {
+		/*
+		 * partcmd_update w/o newmask:
+		 *
+		 * delmask = cpus_allowed & parent->subparts_cpus
+		 * addmask = cpus_allowed & parent->cpus_allowed
+		 *			  & ~parent->subparts_cpus
+		 *
+		 * This gets invoked either due to a hotplug event or from
+		 * update_cpumasks_hier(). This can cause the state of a
+		 * partition root to transition from valid to invalid or vice
+		 * versa. So we still need to compute the addmask and delmask.
+
+		 * A partition error happens when:
+		 * 1) Cpuset is valid partition, but parent does not distribute
+		 *    out any CPUs.
+		 * 2) Parent has tasks and all its effective CPUs will have
+		 *    to be distributed out.
+		 */
+		cpumask_and(tmp->addmask, cs->cpus_allowed,
+					  parent->cpus_allowed);
+		adding = cpumask_andnot(tmp->addmask, tmp->addmask,
+					parent->subparts_cpus);
+
+		if ((is_partition_valid(cs) && !parent->nr_subparts_cpus) ||
+		    (adding &&
+		     cpumask_subset(parent->effective_cpus, tmp->addmask) &&
+		     partition_is_populated(parent, cs))) {
+			part_error = PERR_NOCPUS;
+			adding = false;
+		}
+
+		if (part_error && is_partition_valid(cs) &&
+		    parent->nr_subparts_cpus)
+			deleting = cpumask_and(tmp->delmask, cs->cpus_allowed,
+					       parent->subparts_cpus);
+	}
+	if (part_error)
+		WRITE_ONCE(cs->prs_err, part_error);
+
+	if (cmd == partcmd_update) {
+		/*
+		 * Check for possible transition between valid and invalid
+		 * partition root.
+		 */
+		switch (cs->partition_root_state) {
+		case PRS_ROOT:
+		case PRS_ISOLATED:
+			if (part_error)
+				new_prs = -old_prs;
+			break;
+		case PRS_INVALID_ROOT:
+		case PRS_INVALID_ISOLATED:
+			if (!part_error)
+				new_prs = -old_prs;
+			break;
+		}
+	}
+
+	if (!adding && !deleting && (new_prs == old_prs))
+		return 0;
+
+	/*
+	 * Transitioning between invalid to valid or vice versa may require
+	 * changing CS_CPU_EXCLUSIVE and CS_SCHED_LOAD_BALANCE.
+	 */
+	if (old_prs != new_prs) {
+		if (is_prs_invalid(old_prs) && !is_cpu_exclusive(cs) &&
+		    (update_flag(CS_CPU_EXCLUSIVE, cs, 1) < 0))
+			return PERR_NOTEXCL;
+		if (is_prs_invalid(new_prs) && is_cpu_exclusive(cs))
+			update_flag(CS_CPU_EXCLUSIVE, cs, 0);
+	}
+
+	/*
+	 * Change the parent's subparts_cpus.
+	 * Newly added CPUs will be removed from effective_cpus and
+	 * newly deleted ones will be added back to effective_cpus.
+	 */
+	spin_lock_irq(&callback_lock);
+	if (adding) {
+		cpumask_or(parent->subparts_cpus,
+			   parent->subparts_cpus, tmp->addmask);
+		cpumask_andnot(parent->effective_cpus,
+			       parent->effective_cpus, tmp->addmask);
+	}
+	if (deleting) {
+		cpumask_andnot(parent->subparts_cpus,
+			       parent->subparts_cpus, tmp->delmask);
+		/*
+		 * Some of the CPUs in subparts_cpus might have been offlined.
+		 */
+		cpumask_and(tmp->delmask, tmp->delmask, cpu_active_mask);
+		cpumask_or(parent->effective_cpus,
+			   parent->effective_cpus, tmp->delmask);
+	}
+
+	parent->nr_subparts_cpus = cpumask_weight(parent->subparts_cpus);
+
+	if (old_prs != new_prs)
+		cs->partition_root_state = new_prs;
+
+	spin_unlock_irq(&callback_lock);
+
+	if (adding || deleting)
+		update_tasks_cpumask(parent, tmp->addmask);
+
+	/*
+	 * Set or clear CS_SCHED_LOAD_BALANCE when partcmd_update, if necessary.
+	 * rebuild_sched_domains_locked() may be called.
+	 */
+	if (old_prs != new_prs) {
+		if (old_prs == PRS_ISOLATED)
+			update_flag(CS_SCHED_LOAD_BALANCE, cs, 1);
+		else if (new_prs == PRS_ISOLATED)
+			update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
+	}
+	notify_partition_change(cs, old_prs);
+	return 0;
+}
+
+/*
+ * update_cpumasks_hier - Update effective cpumasks and tasks in the subtree
+ * @cs:  the cpuset to consider
+ * @tmp: temp variables for calculating effective_cpus & partition setup
+ * @force: don't skip any descendant cpusets if set
+ *
+ * When configured cpumask is changed, the effective cpumasks of this cpuset
+ * and all its descendants need to be updated.
+ *
+ * On legacy hierarchy, effective_cpus will be the same with cpu_allowed.
+ *
+ * Called with cpuset_mutex held
+ */
+static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp,
+				 bool force)
+{
+	struct cpuset *cp;
+	struct cgroup_subsys_state *pos_css;
+	bool need_rebuild_sched_domains = false;
+	int old_prs, new_prs;
+
+	rcu_read_lock();
+	cpuset_for_each_descendant_pre(cp, pos_css, cs) {
+		struct cpuset *parent = parent_cs(cp);
+		bool update_parent = false;
+
+		compute_effective_cpumask(tmp->new_cpus, cp, parent);
+
+		/*
+		 * If it becomes empty, inherit the effective mask of the
+		 * parent, which is guaranteed to have some CPUs unless
+		 * it is a partition root that has explicitly distributed
+		 * out all its CPUs.
+		 */
+		if (is_in_v2_mode() && cpumask_empty(tmp->new_cpus)) {
+			if (is_partition_valid(cp) &&
+			    cpumask_equal(cp->cpus_allowed, cp->subparts_cpus))
+				goto update_parent_subparts;
+
+			cpumask_copy(tmp->new_cpus, parent->effective_cpus);
+			if (!cp->use_parent_ecpus) {
+				cp->use_parent_ecpus = true;
+				parent->child_ecpus_count++;
+			}
+		} else if (cp->use_parent_ecpus) {
+			cp->use_parent_ecpus = false;
+			WARN_ON_ONCE(!parent->child_ecpus_count);
+			parent->child_ecpus_count--;
+		}
+
+		/*
+		 * Skip the whole subtree if
+		 * 1) the cpumask remains the same,
+		 * 2) has no partition root state,
+		 * 3) force flag not set, and
+		 * 4) for v2 load balance state same as its parent.
+		 */
+		if (!cp->partition_root_state && !force &&
+		    cpumask_equal(tmp->new_cpus, cp->effective_cpus) &&
+		    (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
+		    (is_sched_load_balance(parent) == is_sched_load_balance(cp)))) {
+			pos_css = css_rightmost_descendant(pos_css);
+			continue;
+		}
+
+update_parent_subparts:
+		/*
+		 * update_parent_subparts_cpumask() should have been called
+		 * for cs already in update_cpumask(). We should also call
+		 * update_tasks_cpumask() again for tasks in the parent
+		 * cpuset if the parent's subparts_cpus changes.
+		 */
+		old_prs = new_prs = cp->partition_root_state;
+		if ((cp != cs) && old_prs) {
+			switch (parent->partition_root_state) {
+			case PRS_ROOT:
+			case PRS_ISOLATED:
+				update_parent = true;
+				break;
+
+			default:
+				/*
+				 * When parent is not a partition root or is
+				 * invalid, child partition roots become
+				 * invalid too.
+				 */
+				if (is_partition_valid(cp))
+					new_prs = -cp->partition_root_state;
+				WRITE_ONCE(cp->prs_err,
+					   is_partition_invalid(parent)
+					   ? PERR_INVPARENT : PERR_NOTPART);
+				break;
+			}
+		}
+
+		if (!css_tryget_online(&cp->css))
+			continue;
+		rcu_read_unlock();
+
+		if (update_parent) {
+			update_parent_subparts_cpumask(cp, partcmd_update, NULL,
+						       tmp);
+			/*
+			 * The cpuset partition_root_state may become
+			 * invalid. Capture it.
+			 */
+			new_prs = cp->partition_root_state;
+		}
+
+		spin_lock_irq(&callback_lock);
+
+		if (cp->nr_subparts_cpus && !is_partition_valid(cp)) {
+			/*
+			 * Put all active subparts_cpus back to effective_cpus.
+			 */
+			cpumask_or(tmp->new_cpus, tmp->new_cpus,
+				   cp->subparts_cpus);
+			cpumask_and(tmp->new_cpus, tmp->new_cpus,
+				   cpu_active_mask);
+			cp->nr_subparts_cpus = 0;
+			cpumask_clear(cp->subparts_cpus);
+		}
+
+		cpumask_copy(cp->effective_cpus, tmp->new_cpus);
+		if (cp->nr_subparts_cpus) {
+			/*
+			 * Make sure that effective_cpus & subparts_cpus
+			 * are mutually exclusive.
+			 */
+			cpumask_andnot(cp->effective_cpus, cp->effective_cpus,
+				       cp->subparts_cpus);
+		}
+
+		cp->partition_root_state = new_prs;
+		spin_unlock_irq(&callback_lock);
+
+		notify_partition_change(cp, old_prs);
+
+		WARN_ON(!is_in_v2_mode() &&
+			!cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
+
+		update_tasks_cpumask(cp, tmp->new_cpus);
+
+		/*
+		 * On default hierarchy, inherit the CS_SCHED_LOAD_BALANCE
+		 * from parent if current cpuset isn't a valid partition root
+		 * and their load balance states differ.
+		 */
+		if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
+		    !is_partition_valid(cp) &&
+		    (is_sched_load_balance(parent) != is_sched_load_balance(cp))) {
+			if (is_sched_load_balance(parent))
+				set_bit(CS_SCHED_LOAD_BALANCE, &cp->flags);
+			else
+				clear_bit(CS_SCHED_LOAD_BALANCE, &cp->flags);
+		}
+
+		/*
+		 * On legacy hierarchy, if the effective cpumask of any non-
+		 * empty cpuset is changed, we need to rebuild sched domains.
+		 * On default hierarchy, the cpuset needs to be a partition
+		 * root as well.
+		 */
+		if (!cpumask_empty(cp->cpus_allowed) &&
+		    is_sched_load_balance(cp) &&
+		   (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
+		    is_partition_valid(cp)))
+			need_rebuild_sched_domains = true;
+
+		rcu_read_lock();
+		css_put(&cp->css);
+	}
+	rcu_read_unlock();
+
+	if (need_rebuild_sched_domains)
+		rebuild_sched_domains_locked();
+}
+
+/**
+ * update_sibling_cpumasks - Update siblings cpumasks
+ * @parent:  Parent cpuset
+ * @cs:      Current cpuset
+ * @tmp:     Temp variables
+ */
+static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
+				    struct tmpmasks *tmp)
+{
+	struct cpuset *sibling;
+	struct cgroup_subsys_state *pos_css;
+
+	lockdep_assert_held(&cpuset_mutex);
+
+	/*
+	 * Check all its siblings and call update_cpumasks_hier()
+	 * if their use_parent_ecpus flag is set in order for them
+	 * to use the right effective_cpus value.
+	 *
+	 * The update_cpumasks_hier() function may sleep. So we have to
+	 * release the RCU read lock before calling it.
+	 */
+	rcu_read_lock();
+	cpuset_for_each_child(sibling, pos_css, parent) {
+		if (sibling == cs)
+			continue;
+		if (!sibling->use_parent_ecpus)
+			continue;
+		if (!css_tryget_online(&sibling->css))
+			continue;
+
+		rcu_read_unlock();
+		update_cpumasks_hier(sibling, tmp, false);
+		rcu_read_lock();
+		css_put(&sibling->css);
+	}
+	rcu_read_unlock();
+}
+
+/**
+ * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
+ * @cs: the cpuset to consider
+ * @trialcs: trial cpuset
+ * @buf: buffer of cpu numbers written to this cpuset
+ */
+static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
+			  const char *buf)
+{
+	int retval;
+	struct tmpmasks tmp;
+	bool invalidate = false;
+
+	/* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */
+	if (cs == &top_cpuset)
+		return -EACCES;
+
+	/*
+	 * An empty cpus_allowed is ok only if the cpuset has no tasks.
+	 * Since cpulist_parse() fails on an empty mask, we special case
+	 * that parsing.  The validate_change() call ensures that cpusets
+	 * with tasks have cpus.
+	 */
+	if (!*buf) {
+		cpumask_clear(trialcs->cpus_allowed);
+	} else {
+		retval = cpulist_parse(buf, trialcs->cpus_allowed);
+		if (retval < 0)
+			return retval;
+
+		if (!cpumask_subset(trialcs->cpus_allowed,
+				    top_cpuset.cpus_allowed))
+			return -EINVAL;
+	}
+
+	/* Nothing to do if the cpus didn't change */
+	if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
+		return 0;
+
+#ifdef CONFIG_CPUMASK_OFFSTACK
+	/*
+	 * Use the cpumasks in trialcs for tmpmasks when they are pointers
+	 * to allocated cpumasks.
+	 *
+	 * Note that update_parent_subparts_cpumask() uses only addmask &
+	 * delmask, but not new_cpus.
+	 */
+	tmp.addmask  = trialcs->subparts_cpus;
+	tmp.delmask  = trialcs->effective_cpus;
+	tmp.new_cpus = NULL;
+#endif
+
+	retval = validate_change(cs, trialcs);
+
+	if ((retval == -EINVAL) && cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) {
+		struct cpuset *cp, *parent;
+		struct cgroup_subsys_state *css;
+
+		/*
+		 * The -EINVAL error code indicates that partition sibling
+		 * CPU exclusivity rule has been violated. We still allow
+		 * the cpumask change to proceed while invalidating the
+		 * partition. However, any conflicting sibling partitions
+		 * have to be marked as invalid too.
+		 */
+		invalidate = true;
+		rcu_read_lock();
+		parent = parent_cs(cs);
+		cpuset_for_each_child(cp, css, parent)
+			if (is_partition_valid(cp) &&
+			    cpumask_intersects(trialcs->cpus_allowed, cp->cpus_allowed)) {
+				rcu_read_unlock();
+				update_parent_subparts_cpumask(cp, partcmd_invalidate, NULL, &tmp);
+				rcu_read_lock();
+			}
+		rcu_read_unlock();
+		retval = 0;
+	}
+	if (retval < 0)
+		return retval;
+
+	if (cs->partition_root_state) {
+		if (invalidate)
+			update_parent_subparts_cpumask(cs, partcmd_invalidate,
+						       NULL, &tmp);
+		else
+			update_parent_subparts_cpumask(cs, partcmd_update,
+						trialcs->cpus_allowed, &tmp);
+	}
+
+	compute_effective_cpumask(trialcs->effective_cpus, trialcs,
+				  parent_cs(cs));
+	spin_lock_irq(&callback_lock);
+	cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
+
+	/*
+	 * Make sure that subparts_cpus, if not empty, is a subset of
+	 * cpus_allowed. Clear subparts_cpus if partition not valid or
+	 * empty effective cpus with tasks.
+	 */
+	if (cs->nr_subparts_cpus) {
+		if (!is_partition_valid(cs) ||
+		   (cpumask_subset(trialcs->effective_cpus, cs->subparts_cpus) &&
+		    partition_is_populated(cs, NULL))) {
+			cs->nr_subparts_cpus = 0;
+			cpumask_clear(cs->subparts_cpus);
+		} else {
+			cpumask_and(cs->subparts_cpus, cs->subparts_cpus,
+				    cs->cpus_allowed);
+			cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
+		}
+	}
+	spin_unlock_irq(&callback_lock);
+
+#ifdef CONFIG_CPUMASK_OFFSTACK
+	/* Now trialcs->cpus_allowed is available */
+	tmp.new_cpus = trialcs->cpus_allowed;
+#endif
+
+	/* effective_cpus will be updated here */
+	update_cpumasks_hier(cs, &tmp, false);
+
+	if (cs->partition_root_state) {
+		struct cpuset *parent = parent_cs(cs);
+
+		/*
+		 * For partition root, update the cpumasks of sibling
+		 * cpusets if they use parent's effective_cpus.
+		 */
+		if (parent->child_ecpus_count)
+			update_sibling_cpumasks(parent, cs, &tmp);
+	}
+	return 0;
+}
+
+/*
+ * Migrate memory region from one set of nodes to another.  This is
+ * performed asynchronously as it can be called from process migration path
+ * holding locks involved in process management.  All mm migrations are
+ * performed in the queued order and can be waited for by flushing
+ * cpuset_migrate_mm_wq.
+ */
+
+struct cpuset_migrate_mm_work {
+	struct work_struct	work;
+	struct mm_struct	*mm;
+	nodemask_t		from;
+	nodemask_t		to;
+};
+
+static void cpuset_migrate_mm_workfn(struct work_struct *work)
+{
+	struct cpuset_migrate_mm_work *mwork =
+		container_of(work, struct cpuset_migrate_mm_work, work);
+
+	/* on a wq worker, no need to worry about %current's mems_allowed */
+	do_migrate_pages(mwork->mm, &mwork->from, &mwork->to, MPOL_MF_MOVE_ALL);
+	mmput(mwork->mm);
+	kfree(mwork);
+}
+
+static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
+							const nodemask_t *to)
+{
+	struct cpuset_migrate_mm_work *mwork;
+
+	if (nodes_equal(*from, *to)) {
+		mmput(mm);
+		return;
+	}
+
+	mwork = kzalloc(sizeof(*mwork), GFP_KERNEL);
+	if (mwork) {
+		mwork->mm = mm;
+		mwork->from = *from;
+		mwork->to = *to;
+		INIT_WORK(&mwork->work, cpuset_migrate_mm_workfn);
+		queue_work(cpuset_migrate_mm_wq, &mwork->work);
+	} else {
+		mmput(mm);
+	}
+}
+
+static void cpuset_post_attach(void)
+{
+	flush_workqueue(cpuset_migrate_mm_wq);
+}
+
+/*
+ * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy
+ * @tsk: the task to change
+ * @newmems: new nodes that the task will be set
+ *
+ * We use the mems_allowed_seq seqlock to safely update both tsk->mems_allowed
+ * and rebind an eventual tasks' mempolicy. If the task is allocating in
+ * parallel, it might temporarily see an empty intersection, which results in
+ * a seqlock check and retry before OOM or allocation failure.
+ */
+static void cpuset_change_task_nodemask(struct task_struct *tsk,
+					nodemask_t *newmems)
+{
+	task_lock(tsk);
+
+	local_irq_disable();
+	write_seqcount_begin(&tsk->mems_allowed_seq);
+
+	nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
+	mpol_rebind_task(tsk, newmems);
+	tsk->mems_allowed = *newmems;
+
+	write_seqcount_end(&tsk->mems_allowed_seq);
+	local_irq_enable();
+
+	task_unlock(tsk);
+}
+
+static void *cpuset_being_rebound;
+
+/**
+ * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.
+ * @cs: the cpuset in which each task's mems_allowed mask needs to be changed
+ *
+ * Iterate through each task of @cs updating its mems_allowed to the
+ * effective cpuset's.  As this function is called with cpuset_mutex held,
+ * cpuset membership stays stable.
+ */
+static void update_tasks_nodemask(struct cpuset *cs)
+{
+	static nodemask_t newmems;	/* protected by cpuset_mutex */
+	struct css_task_iter it;
+	struct task_struct *task;
+
+	cpuset_being_rebound = cs;		/* causes mpol_dup() rebind */
+
+	guarantee_online_mems(cs, &newmems);
+
+	/*
+	 * The mpol_rebind_mm() call takes mmap_lock, which we couldn't
+	 * take while holding tasklist_lock.  Forks can happen - the
+	 * mpol_dup() cpuset_being_rebound check will catch such forks,
+	 * and rebind their vma mempolicies too.  Because we still hold
+	 * the global cpuset_mutex, we know that no other rebind effort
+	 * will be contending for the global variable cpuset_being_rebound.
+	 * It's ok if we rebind the same mm twice; mpol_rebind_mm()
+	 * is idempotent.  Also migrate pages in each mm to new nodes.
+	 */
+	css_task_iter_start(&cs->css, 0, &it);
+	while ((task = css_task_iter_next(&it))) {
+		struct mm_struct *mm;
+		bool migrate;
+
+		cpuset_change_task_nodemask(task, &newmems);
+
+		mm = get_task_mm(task);
+		if (!mm)
+			continue;
+
+		migrate = is_memory_migrate(cs);
+
+		mpol_rebind_mm(mm, &cs->mems_allowed);
+		if (migrate)
+			cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems);
+		else
+			mmput(mm);
+	}
+	css_task_iter_end(&it);
+
+	/*
+	 * All the tasks' nodemasks have been updated, update
+	 * cs->old_mems_allowed.
+	 */
+	cs->old_mems_allowed = newmems;
+
+	/* We're done rebinding vmas to this cpuset's new mems_allowed. */
+	cpuset_being_rebound = NULL;
+}
+
+/*
+ * update_nodemasks_hier - Update effective nodemasks and tasks in the subtree
+ * @cs: the cpuset to consider
+ * @new_mems: a temp variable for calculating new effective_mems
+ *
+ * When configured nodemask is changed, the effective nodemasks of this cpuset
+ * and all its descendants need to be updated.
+ *
+ * On legacy hierarchy, effective_mems will be the same with mems_allowed.
+ *
+ * Called with cpuset_mutex held
+ */
+static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
+{
+	struct cpuset *cp;
+	struct cgroup_subsys_state *pos_css;
+
+	rcu_read_lock();
+	cpuset_for_each_descendant_pre(cp, pos_css, cs) {
+		struct cpuset *parent = parent_cs(cp);
+
+		nodes_and(*new_mems, cp->mems_allowed, parent->effective_mems);
+
+		/*
+		 * If it becomes empty, inherit the effective mask of the
+		 * parent, which is guaranteed to have some MEMs.
+		 */
+		if (is_in_v2_mode() && nodes_empty(*new_mems))
+			*new_mems = parent->effective_mems;
+
+		/* Skip the whole subtree if the nodemask remains the same. */
+		if (nodes_equal(*new_mems, cp->effective_mems)) {
+			pos_css = css_rightmost_descendant(pos_css);
+			continue;
+		}
+
+		if (!css_tryget_online(&cp->css))
+			continue;
+		rcu_read_unlock();
+
+		spin_lock_irq(&callback_lock);
+		cp->effective_mems = *new_mems;
+		spin_unlock_irq(&callback_lock);
+
+		WARN_ON(!is_in_v2_mode() &&
+			!nodes_equal(cp->mems_allowed, cp->effective_mems));
+
+		update_tasks_nodemask(cp);
+
+		rcu_read_lock();
+		css_put(&cp->css);
+	}
+	rcu_read_unlock();
+}
+
+/*
+ * Handle user request to change the 'mems' memory placement
+ * of a cpuset.  Needs to validate the request, update the
+ * cpusets mems_allowed, and for each task in the cpuset,
+ * update mems_allowed and rebind task's mempolicy and any vma
+ * mempolicies and if the cpuset is marked 'memory_migrate',
+ * migrate the tasks pages to the new memory.
+ *
+ * Call with cpuset_mutex held. May take callback_lock during call.
+ * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
+ * lock each such tasks mm->mmap_lock, scan its vma's and rebind
+ * their mempolicies to the cpusets new mems_allowed.
+ */
+static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
+			   const char *buf)
+{
+	int retval;
+
+	/*
+	 * top_cpuset.mems_allowed tracks node_stats[N_MEMORY];
+	 * it's read-only
+	 */
+	if (cs == &top_cpuset) {
+		retval = -EACCES;
+		goto done;
+	}
+
+	/*
+	 * An empty mems_allowed is ok iff there are no tasks in the cpuset.
+	 * Since nodelist_parse() fails on an empty mask, we special case
+	 * that parsing.  The validate_change() call ensures that cpusets
+	 * with tasks have memory.
+	 */
+	if (!*buf) {
+		nodes_clear(trialcs->mems_allowed);
+	} else {
+		retval = nodelist_parse(buf, trialcs->mems_allowed);
+		if (retval < 0)
+			goto done;
+
+		if (!nodes_subset(trialcs->mems_allowed,
+				  top_cpuset.mems_allowed)) {
+			retval = -EINVAL;
+			goto done;
+		}
+	}
+
+	if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) {
+		retval = 0;		/* Too easy - nothing to do */
+		goto done;
+	}
+	retval = validate_change(cs, trialcs);
+	if (retval < 0)
+		goto done;
+
+	check_insane_mems_config(&trialcs->mems_allowed);
+
+	spin_lock_irq(&callback_lock);
+	cs->mems_allowed = trialcs->mems_allowed;
+	spin_unlock_irq(&callback_lock);
+
+	/* use trialcs->mems_allowed as a temp variable */
+	update_nodemasks_hier(cs, &trialcs->mems_allowed);
+done:
+	return retval;
+}
+
+bool current_cpuset_is_being_rebound(void)
+{
+	bool ret;
+
+	rcu_read_lock();
+	ret = task_cs(current) == cpuset_being_rebound;
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static int update_relax_domain_level(struct cpuset *cs, s64 val)
+{
+#ifdef CONFIG_SMP
+	if (val < -1 || val >= sched_domain_level_max)
+		return -EINVAL;
+#endif
+
+	if (val != cs->relax_domain_level) {
+		cs->relax_domain_level = val;
+		if (!cpumask_empty(cs->cpus_allowed) &&
+		    is_sched_load_balance(cs))
+			rebuild_sched_domains_locked();
+	}
+
+	return 0;
+}
+
+/**
+ * update_tasks_flags - update the spread flags of tasks in the cpuset.
+ * @cs: the cpuset in which each task's spread flags needs to be changed
+ *
+ * Iterate through each task of @cs updating its spread flags.  As this
+ * function is called with cpuset_mutex held, cpuset membership stays
+ * stable.
+ */
+static void update_tasks_flags(struct cpuset *cs)
+{
+	struct css_task_iter it;
+	struct task_struct *task;
+
+	css_task_iter_start(&cs->css, 0, &it);
+	while ((task = css_task_iter_next(&it)))
+		cpuset_update_task_spread_flags(cs, task);
+	css_task_iter_end(&it);
+}
+
+/*
+ * update_flag - read a 0 or a 1 in a file and update associated flag
+ * bit:		the bit to update (see cpuset_flagbits_t)
+ * cs:		the cpuset to update
+ * turning_on: 	whether the flag is being set or cleared
+ *
+ * Call with cpuset_mutex held.
+ */
+
+static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
+		       int turning_on)
+{
+	struct cpuset *trialcs;
+	int balance_flag_changed;
+	int spread_flag_changed;
+	int err;
+
+	trialcs = alloc_trial_cpuset(cs);
+	if (!trialcs)
+		return -ENOMEM;
+
+	if (turning_on)
+		set_bit(bit, &trialcs->flags);
+	else
+		clear_bit(bit, &trialcs->flags);
+
+	err = validate_change(cs, trialcs);
+	if (err < 0)
+		goto out;
+
+	balance_flag_changed = (is_sched_load_balance(cs) !=
+				is_sched_load_balance(trialcs));
+
+	spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
+			|| (is_spread_page(cs) != is_spread_page(trialcs)));
+
+	spin_lock_irq(&callback_lock);
+	cs->flags = trialcs->flags;
+	spin_unlock_irq(&callback_lock);
+
+	if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
+		rebuild_sched_domains_locked();
+
+	if (spread_flag_changed)
+		update_tasks_flags(cs);
+out:
+	free_cpuset(trialcs);
+	return err;
+}
+
+/**
+ * update_prstate - update partition_root_state
+ * @cs: the cpuset to update
+ * @new_prs: new partition root state
+ * Return: 0 if successful, != 0 if error
+ *
+ * Call with cpuset_mutex held.
+ */
+static int update_prstate(struct cpuset *cs, int new_prs)
+{
+	int err = PERR_NONE, old_prs = cs->partition_root_state;
+	bool sched_domain_rebuilt = false;
+	struct cpuset *parent = parent_cs(cs);
+	struct tmpmasks tmpmask;
+
+	if (old_prs == new_prs)
+		return 0;
+
+	/*
+	 * For a previously invalid partition root, leave it at being
+	 * invalid if new_prs is not "member".
+	 */
+	if (new_prs && is_prs_invalid(old_prs)) {
+		cs->partition_root_state = -new_prs;
+		return 0;
+	}
+
+	if (alloc_cpumasks(NULL, &tmpmask))
+		return -ENOMEM;
+
+	if (!old_prs) {
+		/*
+		 * Turning on partition root requires setting the
+		 * CS_CPU_EXCLUSIVE bit implicitly as well and cpus_allowed
+		 * cannot be empty.
+		 */
+		if (cpumask_empty(cs->cpus_allowed)) {
+			err = PERR_CPUSEMPTY;
+			goto out;
+		}
+
+		err = update_flag(CS_CPU_EXCLUSIVE, cs, 1);
+		if (err) {
+			err = PERR_NOTEXCL;
+			goto out;
+		}
+
+		err = update_parent_subparts_cpumask(cs, partcmd_enable,
+						     NULL, &tmpmask);
+		if (err) {
+			update_flag(CS_CPU_EXCLUSIVE, cs, 0);
+			goto out;
+		}
+
+		if (new_prs == PRS_ISOLATED) {
+			/*
+			 * Disable the load balance flag should not return an
+			 * error unless the system is running out of memory.
+			 */
+			update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
+			sched_domain_rebuilt = true;
+		}
+	} else if (old_prs && new_prs) {
+		/*
+		 * A change in load balance state only, no change in cpumasks.
+		 */
+		update_flag(CS_SCHED_LOAD_BALANCE, cs, (new_prs != PRS_ISOLATED));
+		sched_domain_rebuilt = true;
+		goto out;	/* Sched domain is rebuilt in update_flag() */
+	} else {
+		/*
+		 * Switching back to member is always allowed even if it
+		 * disables child partitions.
+		 */
+		update_parent_subparts_cpumask(cs, partcmd_disable, NULL,
+					       &tmpmask);
+
+		/*
+		 * If there are child partitions, they will all become invalid.
+		 */
+		if (unlikely(cs->nr_subparts_cpus)) {
+			spin_lock_irq(&callback_lock);
+			cs->nr_subparts_cpus = 0;
+			cpumask_clear(cs->subparts_cpus);
+			compute_effective_cpumask(cs->effective_cpus, cs, parent);
+			spin_unlock_irq(&callback_lock);
+		}
+
+		/* Turning off CS_CPU_EXCLUSIVE will not return error */
+		update_flag(CS_CPU_EXCLUSIVE, cs, 0);
+
+		if (!is_sched_load_balance(cs)) {
+			/* Make sure load balance is on */
+			update_flag(CS_SCHED_LOAD_BALANCE, cs, 1);
+			sched_domain_rebuilt = true;
+		}
+	}
+
+	update_tasks_cpumask(parent, tmpmask.new_cpus);
+
+	if (parent->child_ecpus_count)
+		update_sibling_cpumasks(parent, cs, &tmpmask);
+
+	if (!sched_domain_rebuilt)
+		rebuild_sched_domains_locked();
+out:
+	/*
+	 * Make partition invalid if an error happen
+	 */
+	if (err)
+		new_prs = -new_prs;
+	spin_lock_irq(&callback_lock);
+	cs->partition_root_state = new_prs;
+	WRITE_ONCE(cs->prs_err, err);
+	spin_unlock_irq(&callback_lock);
+	/*
+	 * Update child cpusets, if present.
+	 * Force update if switching back to member.
+	 */
+	if (!list_empty(&cs->css.children))
+		update_cpumasks_hier(cs, &tmpmask, !new_prs);
+
+	notify_partition_change(cs, old_prs);
+	free_cpumasks(NULL, &tmpmask);
+	return 0;
+}
+
+/*
+ * Frequency meter - How fast is some event occurring?
+ *
+ * These routines manage a digitally filtered, constant time based,
+ * event frequency meter.  There are four routines:
+ *   fmeter_init() - initialize a frequency meter.
+ *   fmeter_markevent() - called each time the event happens.
+ *   fmeter_getrate() - returns the recent rate of such events.
+ *   fmeter_update() - internal routine used to update fmeter.
+ *
+ * A common data structure is passed to each of these routines,
+ * which is used to keep track of the state required to manage the
+ * frequency meter and its digital filter.
+ *
+ * The filter works on the number of events marked per unit time.
+ * The filter is single-pole low-pass recursive (IIR).  The time unit
+ * is 1 second.  Arithmetic is done using 32-bit integers scaled to
+ * simulate 3 decimal digits of precision (multiplied by 1000).
+ *
+ * With an FM_COEF of 933, and a time base of 1 second, the filter
+ * has a half-life of 10 seconds, meaning that if the events quit
+ * happening, then the rate returned from the fmeter_getrate()
+ * will be cut in half each 10 seconds, until it converges to zero.
+ *
+ * It is not worth doing a real infinitely recursive filter.  If more
+ * than FM_MAXTICKS ticks have elapsed since the last filter event,
+ * just compute FM_MAXTICKS ticks worth, by which point the level
+ * will be stable.
+ *
+ * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid
+ * arithmetic overflow in the fmeter_update() routine.
+ *
+ * Given the simple 32 bit integer arithmetic used, this meter works
+ * best for reporting rates between one per millisecond (msec) and
+ * one per 32 (approx) seconds.  At constant rates faster than one
+ * per msec it maxes out at values just under 1,000,000.  At constant
+ * rates between one per msec, and one per second it will stabilize
+ * to a value N*1000, where N is the rate of events per second.
+ * At constant rates between one per second and one per 32 seconds,
+ * it will be choppy, moving up on the seconds that have an event,
+ * and then decaying until the next event.  At rates slower than
+ * about one in 32 seconds, it decays all the way back to zero between
+ * each event.
+ */
+
+#define FM_COEF 933		/* coefficient for half-life of 10 secs */
+#define FM_MAXTICKS ((u32)99)   /* useless computing more ticks than this */
+#define FM_MAXCNT 1000000	/* limit cnt to avoid overflow */
+#define FM_SCALE 1000		/* faux fixed point scale */
+
+/* Initialize a frequency meter */
+static void fmeter_init(struct fmeter *fmp)
+{
+	fmp->cnt = 0;
+	fmp->val = 0;
+	fmp->time = 0;
+	spin_lock_init(&fmp->lock);
+}
+
+/* Internal meter update - process cnt events and update value */
+static void fmeter_update(struct fmeter *fmp)
+{
+	time64_t now;
+	u32 ticks;
+
+	now = ktime_get_seconds();
+	ticks = now - fmp->time;
+
+	if (ticks == 0)
+		return;
+
+	ticks = min(FM_MAXTICKS, ticks);
+	while (ticks-- > 0)
+		fmp->val = (FM_COEF * fmp->val) / FM_SCALE;
+	fmp->time = now;
+
+	fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE;
+	fmp->cnt = 0;
+}
+
+/* Process any previous ticks, then bump cnt by one (times scale). */
+static void fmeter_markevent(struct fmeter *fmp)
+{
+	spin_lock(&fmp->lock);
+	fmeter_update(fmp);
+	fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE);
+	spin_unlock(&fmp->lock);
+}
+
+/* Process any previous ticks, then return current value. */
+static int fmeter_getrate(struct fmeter *fmp)
+{
+	int val;
+
+	spin_lock(&fmp->lock);
+	fmeter_update(fmp);
+	val = fmp->val;
+	spin_unlock(&fmp->lock);
+	return val;
+}
+
+static struct cpuset *cpuset_attach_old_cs;
+
+/*
+ * Check to see if a cpuset can accept a new task
+ * For v1, cpus_allowed and mems_allowed can't be empty.
+ * For v2, effective_cpus can't be empty.
+ * Note that in v1, effective_cpus = cpus_allowed.
+ */
+static int cpuset_can_attach_check(struct cpuset *cs)
+{
+	if (cpumask_empty(cs->effective_cpus) ||
+	   (!is_in_v2_mode() && nodes_empty(cs->mems_allowed)))
+		return -ENOSPC;
+	return 0;
+}
+
+static void reset_migrate_dl_data(struct cpuset *cs)
+{
+	cs->nr_migrate_dl_tasks = 0;
+	cs->sum_migrate_dl_bw = 0;
+}
+
+/* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held */
+static int cpuset_can_attach(struct cgroup_taskset *tset)
+{
+	struct cgroup_subsys_state *css;
+	struct cpuset *cs, *oldcs;
+	struct task_struct *task;
+	int ret;
+
+	/* used later by cpuset_attach() */
+	cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset, &css));
+	oldcs = cpuset_attach_old_cs;
+	cs = css_cs(css);
+
+	mutex_lock(&cpuset_mutex);
+
+	/* Check to see if task is allowed in the cpuset */
+	ret = cpuset_can_attach_check(cs);
+	if (ret)
+		goto out_unlock;
+
+	cgroup_taskset_for_each(task, css, tset) {
+		ret = task_can_attach(task);
+		if (ret)
+			goto out_unlock;
+		ret = security_task_setscheduler(task);
+		if (ret)
+			goto out_unlock;
+
+		if (dl_task(task)) {
+			cs->nr_migrate_dl_tasks++;
+			cs->sum_migrate_dl_bw += task->dl.dl_bw;
+		}
+	}
+
+	if (!cs->nr_migrate_dl_tasks)
+		goto out_success;
+
+	if (!cpumask_intersects(oldcs->effective_cpus, cs->effective_cpus)) {
+		int cpu = cpumask_any_and(cpu_active_mask, cs->effective_cpus);
+
+		if (unlikely(cpu >= nr_cpu_ids)) {
+			reset_migrate_dl_data(cs);
+			ret = -EINVAL;
+			goto out_unlock;
+		}
+
+		ret = dl_bw_alloc(cpu, cs->sum_migrate_dl_bw);
+		if (ret) {
+			reset_migrate_dl_data(cs);
+			goto out_unlock;
+		}
+	}
+
+out_success:
+	/*
+	 * Mark attach is in progress.  This makes validate_change() fail
+	 * changes which zero cpus/mems_allowed.
+	 */
+	cs->attach_in_progress++;
+out_unlock:
+	mutex_unlock(&cpuset_mutex);
+	return ret;
+}
+
+static void cpuset_cancel_attach(struct cgroup_taskset *tset)
+{
+	struct cgroup_subsys_state *css;
+	struct cpuset *cs;
+
+	cgroup_taskset_first(tset, &css);
+	cs = css_cs(css);
+
+	mutex_lock(&cpuset_mutex);
+	cs->attach_in_progress--;
+	if (!cs->attach_in_progress)
+		wake_up(&cpuset_attach_wq);
+
+	if (cs->nr_migrate_dl_tasks) {
+		int cpu = cpumask_any(cs->effective_cpus);
+
+		dl_bw_free(cpu, cs->sum_migrate_dl_bw);
+		reset_migrate_dl_data(cs);
+	}
+
+	mutex_unlock(&cpuset_mutex);
+}
+
+/*
+ * Protected by cpuset_mutex. cpus_attach is used only by cpuset_attach_task()
+ * but we can't allocate it dynamically there.  Define it global and
+ * allocate from cpuset_init().
+ */
+static cpumask_var_t cpus_attach;
+static nodemask_t cpuset_attach_nodemask_to;
+
+static void cpuset_attach_task(struct cpuset *cs, struct task_struct *task)
+{
+	lockdep_assert_held(&cpuset_mutex);
+
+	if (cs != &top_cpuset)
+		guarantee_online_cpus(task, cpus_attach);
+	else
+		cpumask_copy(cpus_attach, task_cpu_possible_mask(task));
+	/*
+	 * can_attach beforehand should guarantee that this doesn't
+	 * fail.  TODO: have a better way to handle failure here
+	 */
+	WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach));
+
+	cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to);
+	cpuset_update_task_spread_flags(cs, task);
+}
+
+static void cpuset_attach(struct cgroup_taskset *tset)
+{
+	struct task_struct *task;
+	struct task_struct *leader;
+	struct cgroup_subsys_state *css;
+	struct cpuset *cs;
+	struct cpuset *oldcs = cpuset_attach_old_cs;
+
+	cgroup_taskset_first(tset, &css);
+	cs = css_cs(css);
+
+	lockdep_assert_cpus_held();	/* see cgroup_attach_lock() */
+	mutex_lock(&cpuset_mutex);
+
+	guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
+
+	cgroup_taskset_for_each(task, css, tset)
+		cpuset_attach_task(cs, task);
+
+	/*
+	 * Change mm for all threadgroup leaders. This is expensive and may
+	 * sleep and should be moved outside migration path proper.
+	 */
+	cpuset_attach_nodemask_to = cs->effective_mems;
+	cgroup_taskset_for_each_leader(leader, css, tset) {
+		struct mm_struct *mm = get_task_mm(leader);
+
+		if (mm) {
+			mpol_rebind_mm(mm, &cpuset_attach_nodemask_to);
+
+			/*
+			 * old_mems_allowed is the same with mems_allowed
+			 * here, except if this task is being moved
+			 * automatically due to hotplug.  In that case
+			 * @mems_allowed has been updated and is empty, so
+			 * @old_mems_allowed is the right nodesets that we
+			 * migrate mm from.
+			 */
+			if (is_memory_migrate(cs))
+				cpuset_migrate_mm(mm, &oldcs->old_mems_allowed,
+						  &cpuset_attach_nodemask_to);
+			else
+				mmput(mm);
+		}
+	}
+
+	cs->old_mems_allowed = cpuset_attach_nodemask_to;
+
+	if (cs->nr_migrate_dl_tasks) {
+		cs->nr_deadline_tasks += cs->nr_migrate_dl_tasks;
+		oldcs->nr_deadline_tasks -= cs->nr_migrate_dl_tasks;
+		reset_migrate_dl_data(cs);
+	}
+
+	cs->attach_in_progress--;
+	if (!cs->attach_in_progress)
+		wake_up(&cpuset_attach_wq);
+
+	mutex_unlock(&cpuset_mutex);
+}
+
+/* The various types of files and directories in a cpuset file system */
+
+typedef enum {
+	FILE_MEMORY_MIGRATE,
+	FILE_CPULIST,
+	FILE_MEMLIST,
+	FILE_EFFECTIVE_CPULIST,
+	FILE_EFFECTIVE_MEMLIST,
+	FILE_SUBPARTS_CPULIST,
+	FILE_CPU_EXCLUSIVE,
+	FILE_MEM_EXCLUSIVE,
+	FILE_MEM_HARDWALL,
+	FILE_SCHED_LOAD_BALANCE,
+	FILE_PARTITION_ROOT,
+	FILE_SCHED_RELAX_DOMAIN_LEVEL,
+	FILE_MEMORY_PRESSURE_ENABLED,
+	FILE_MEMORY_PRESSURE,
+	FILE_SPREAD_PAGE,
+	FILE_SPREAD_SLAB,
+} cpuset_filetype_t;
+
+static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
+			    u64 val)
+{
+	struct cpuset *cs = css_cs(css);
+	cpuset_filetype_t type = cft->private;
+	int retval = 0;
+
+	cpus_read_lock();
+	mutex_lock(&cpuset_mutex);
+	if (!is_cpuset_online(cs)) {
+		retval = -ENODEV;
+		goto out_unlock;
+	}
+
+	switch (type) {
+	case FILE_CPU_EXCLUSIVE:
+		retval = update_flag(CS_CPU_EXCLUSIVE, cs, val);
+		break;
+	case FILE_MEM_EXCLUSIVE:
+		retval = update_flag(CS_MEM_EXCLUSIVE, cs, val);
+		break;
+	case FILE_MEM_HARDWALL:
+		retval = update_flag(CS_MEM_HARDWALL, cs, val);
+		break;
+	case FILE_SCHED_LOAD_BALANCE:
+		retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val);
+		break;
+	case FILE_MEMORY_MIGRATE:
+		retval = update_flag(CS_MEMORY_MIGRATE, cs, val);
+		break;
+	case FILE_MEMORY_PRESSURE_ENABLED:
+		cpuset_memory_pressure_enabled = !!val;
+		break;
+	case FILE_SPREAD_PAGE:
+		retval = update_flag(CS_SPREAD_PAGE, cs, val);
+		break;
+	case FILE_SPREAD_SLAB:
+		retval = update_flag(CS_SPREAD_SLAB, cs, val);
+		break;
+	default:
+		retval = -EINVAL;
+		break;
+	}
+out_unlock:
+	mutex_unlock(&cpuset_mutex);
+	cpus_read_unlock();
+	return retval;
+}
+
+static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
+			    s64 val)
+{
+	struct cpuset *cs = css_cs(css);
+	cpuset_filetype_t type = cft->private;
+	int retval = -ENODEV;
+
+	cpus_read_lock();
+	mutex_lock(&cpuset_mutex);
+	if (!is_cpuset_online(cs))
+		goto out_unlock;
+
+	switch (type) {
+	case FILE_SCHED_RELAX_DOMAIN_LEVEL:
+		retval = update_relax_domain_level(cs, val);
+		break;
+	default:
+		retval = -EINVAL;
+		break;
+	}
+out_unlock:
+	mutex_unlock(&cpuset_mutex);
+	cpus_read_unlock();
+	return retval;
+}
+
+/*
+ * Common handling for a write to a "cpus" or "mems" file.
+ */
+static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
+				    char *buf, size_t nbytes, loff_t off)
+{
+	struct cpuset *cs = css_cs(of_css(of));
+	struct cpuset *trialcs;
+	int retval = -ENODEV;
+
+	buf = strstrip(buf);
+
+	/*
+	 * CPU or memory hotunplug may leave @cs w/o any execution
+	 * resources, in which case the hotplug code asynchronously updates
+	 * configuration and transfers all tasks to the nearest ancestor
+	 * which can execute.
+	 *
+	 * As writes to "cpus" or "mems" may restore @cs's execution
+	 * resources, wait for the previously scheduled operations before
+	 * proceeding, so that we don't end up keep removing tasks added
+	 * after execution capability is restored.
+	 *
+	 * cpuset_hotplug_work calls back into cgroup core via
+	 * cgroup_transfer_tasks() and waiting for it from a cgroupfs
+	 * operation like this one can lead to a deadlock through kernfs
+	 * active_ref protection.  Let's break the protection.  Losing the
+	 * protection is okay as we check whether @cs is online after
+	 * grabbing cpuset_mutex anyway.  This only happens on the legacy
+	 * hierarchies.
+	 */
+	css_get(&cs->css);
+	kernfs_break_active_protection(of->kn);
+	flush_work(&cpuset_hotplug_work);
+
+	cpus_read_lock();
+	mutex_lock(&cpuset_mutex);
+	if (!is_cpuset_online(cs))
+		goto out_unlock;
+
+	trialcs = alloc_trial_cpuset(cs);
+	if (!trialcs) {
+		retval = -ENOMEM;
+		goto out_unlock;
+	}
+
+	switch (of_cft(of)->private) {
+	case FILE_CPULIST:
+		retval = update_cpumask(cs, trialcs, buf);
+		break;
+	case FILE_MEMLIST:
+		retval = update_nodemask(cs, trialcs, buf);
+		break;
+	default:
+		retval = -EINVAL;
+		break;
+	}
+
+	free_cpuset(trialcs);
+out_unlock:
+	mutex_unlock(&cpuset_mutex);
+	cpus_read_unlock();
+	kernfs_unbreak_active_protection(of->kn);
+	css_put(&cs->css);
+	flush_workqueue(cpuset_migrate_mm_wq);
+	return retval ?: nbytes;
+}
+
+/*
+ * These ascii lists should be read in a single call, by using a user
+ * buffer large enough to hold the entire map.  If read in smaller
+ * chunks, there is no guarantee of atomicity.  Since the display format
+ * used, list of ranges of sequential numbers, is variable length,
+ * and since these maps can change value dynamically, one could read
+ * gibberish by doing partial reads while a list was changing.
+ */
+static int cpuset_common_seq_show(struct seq_file *sf, void *v)
+{
+	struct cpuset *cs = css_cs(seq_css(sf));
+	cpuset_filetype_t type = seq_cft(sf)->private;
+	int ret = 0;
+
+	spin_lock_irq(&callback_lock);
+
+	switch (type) {
+	case FILE_CPULIST:
+		seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->cpus_allowed));
+		break;
+	case FILE_MEMLIST:
+		seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->mems_allowed));
+		break;
+	case FILE_EFFECTIVE_CPULIST:
+		seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->effective_cpus));
+		break;
+	case FILE_EFFECTIVE_MEMLIST:
+		seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->effective_mems));
+		break;
+	case FILE_SUBPARTS_CPULIST:
+		seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->subparts_cpus));
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	spin_unlock_irq(&callback_lock);
+	return ret;
+}
+
+static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+	struct cpuset *cs = css_cs(css);
+	cpuset_filetype_t type = cft->private;
+	switch (type) {
+	case FILE_CPU_EXCLUSIVE:
+		return is_cpu_exclusive(cs);
+	case FILE_MEM_EXCLUSIVE:
+		return is_mem_exclusive(cs);
+	case FILE_MEM_HARDWALL:
+		return is_mem_hardwall(cs);
+	case FILE_SCHED_LOAD_BALANCE:
+		return is_sched_load_balance(cs);
+	case FILE_MEMORY_MIGRATE:
+		return is_memory_migrate(cs);
+	case FILE_MEMORY_PRESSURE_ENABLED:
+		return cpuset_memory_pressure_enabled;
+	case FILE_MEMORY_PRESSURE:
+		return fmeter_getrate(&cs->fmeter);
+	case FILE_SPREAD_PAGE:
+		return is_spread_page(cs);
+	case FILE_SPREAD_SLAB:
+		return is_spread_slab(cs);
+	default:
+		BUG();
+	}
+
+	/* Unreachable but makes gcc happy */
+	return 0;
+}
+
+static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+	struct cpuset *cs = css_cs(css);
+	cpuset_filetype_t type = cft->private;
+	switch (type) {
+	case FILE_SCHED_RELAX_DOMAIN_LEVEL:
+		return cs->relax_domain_level;
+	default:
+		BUG();
+	}
+
+	/* Unreachable but makes gcc happy */
+	return 0;
+}
+
+static int sched_partition_show(struct seq_file *seq, void *v)
+{
+	struct cpuset *cs = css_cs(seq_css(seq));
+	const char *err, *type = NULL;
+
+	switch (cs->partition_root_state) {
+	case PRS_ROOT:
+		seq_puts(seq, "root\n");
+		break;
+	case PRS_ISOLATED:
+		seq_puts(seq, "isolated\n");
+		break;
+	case PRS_MEMBER:
+		seq_puts(seq, "member\n");
+		break;
+	case PRS_INVALID_ROOT:
+		type = "root";
+		fallthrough;
+	case PRS_INVALID_ISOLATED:
+		if (!type)
+			type = "isolated";
+		err = perr_strings[READ_ONCE(cs->prs_err)];
+		if (err)
+			seq_printf(seq, "%s invalid (%s)\n", type, err);
+		else
+			seq_printf(seq, "%s invalid\n", type);
+		break;
+	}
+	return 0;
+}
+
+static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf,
+				     size_t nbytes, loff_t off)
+{
+	struct cpuset *cs = css_cs(of_css(of));
+	int val;
+	int retval = -ENODEV;
+
+	buf = strstrip(buf);
+
+	/*
+	 * Convert "root" to ENABLED, and convert "member" to DISABLED.
+	 */
+	if (!strcmp(buf, "root"))
+		val = PRS_ROOT;
+	else if (!strcmp(buf, "member"))
+		val = PRS_MEMBER;
+	else if (!strcmp(buf, "isolated"))
+		val = PRS_ISOLATED;
+	else
+		return -EINVAL;
+
+	css_get(&cs->css);
+	cpus_read_lock();
+	mutex_lock(&cpuset_mutex);
+	if (!is_cpuset_online(cs))
+		goto out_unlock;
+
+	retval = update_prstate(cs, val);
+out_unlock:
+	mutex_unlock(&cpuset_mutex);
+	cpus_read_unlock();
+	css_put(&cs->css);
+	return retval ?: nbytes;
+}
+
+/*
+ * for the common functions, 'private' gives the type of file
+ */
+
+static struct cftype legacy_files[] = {
+	{
+		.name = "cpus",
+		.seq_show = cpuset_common_seq_show,
+		.write = cpuset_write_resmask,
+		.max_write_len = (100U + 6 * NR_CPUS),
+		.private = FILE_CPULIST,
+	},
+
+	{
+		.name = "mems",
+		.seq_show = cpuset_common_seq_show,
+		.write = cpuset_write_resmask,
+		.max_write_len = (100U + 6 * MAX_NUMNODES),
+		.private = FILE_MEMLIST,
+	},
+
+	{
+		.name = "effective_cpus",
+		.seq_show = cpuset_common_seq_show,
+		.private = FILE_EFFECTIVE_CPULIST,
+	},
+
+	{
+		.name = "effective_mems",
+		.seq_show = cpuset_common_seq_show,
+		.private = FILE_EFFECTIVE_MEMLIST,
+	},
+
+	{
+		.name = "cpu_exclusive",
+		.read_u64 = cpuset_read_u64,
+		.write_u64 = cpuset_write_u64,
+		.private = FILE_CPU_EXCLUSIVE,
+	},
+
+	{
+		.name = "mem_exclusive",
+		.read_u64 = cpuset_read_u64,
+		.write_u64 = cpuset_write_u64,
+		.private = FILE_MEM_EXCLUSIVE,
+	},
+
+	{
+		.name = "mem_hardwall",
+		.read_u64 = cpuset_read_u64,
+		.write_u64 = cpuset_write_u64,
+		.private = FILE_MEM_HARDWALL,
+	},
+
+	{
+		.name = "sched_load_balance",
+		.read_u64 = cpuset_read_u64,
+		.write_u64 = cpuset_write_u64,
+		.private = FILE_SCHED_LOAD_BALANCE,
+	},
+
+	{
+		.name = "sched_relax_domain_level",
+		.read_s64 = cpuset_read_s64,
+		.write_s64 = cpuset_write_s64,
+		.private = FILE_SCHED_RELAX_DOMAIN_LEVEL,
+	},
+
+	{
+		.name = "memory_migrate",
+		.read_u64 = cpuset_read_u64,
+		.write_u64 = cpuset_write_u64,
+		.private = FILE_MEMORY_MIGRATE,
+	},
+
+	{
+		.name = "memory_pressure",
+		.read_u64 = cpuset_read_u64,
+		.private = FILE_MEMORY_PRESSURE,
+	},
+
+	{
+		.name = "memory_spread_page",
+		.read_u64 = cpuset_read_u64,
+		.write_u64 = cpuset_write_u64,
+		.private = FILE_SPREAD_PAGE,
+	},
+
+	{
+		.name = "memory_spread_slab",
+		.read_u64 = cpuset_read_u64,
+		.write_u64 = cpuset_write_u64,
+		.private = FILE_SPREAD_SLAB,
+	},
+
+	{
+		.name = "memory_pressure_enabled",
+		.flags = CFTYPE_ONLY_ON_ROOT,
+		.read_u64 = cpuset_read_u64,
+		.write_u64 = cpuset_write_u64,
+		.private = FILE_MEMORY_PRESSURE_ENABLED,
+	},
+
+	{ }	/* terminate */
+};
+
+/*
+ * This is currently a minimal set for the default hierarchy. It can be
+ * expanded later on by migrating more features and control files from v1.
+ */
+static struct cftype dfl_files[] = {
+	{
+		.name = "cpus",
+		.seq_show = cpuset_common_seq_show,
+		.write = cpuset_write_resmask,
+		.max_write_len = (100U + 6 * NR_CPUS),
+		.private = FILE_CPULIST,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+
+	{
+		.name = "mems",
+		.seq_show = cpuset_common_seq_show,
+		.write = cpuset_write_resmask,
+		.max_write_len = (100U + 6 * MAX_NUMNODES),
+		.private = FILE_MEMLIST,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+
+	{
+		.name = "cpus.effective",
+		.seq_show = cpuset_common_seq_show,
+		.private = FILE_EFFECTIVE_CPULIST,
+	},
+
+	{
+		.name = "mems.effective",
+		.seq_show = cpuset_common_seq_show,
+		.private = FILE_EFFECTIVE_MEMLIST,
+	},
+
+	{
+		.name = "cpus.partition",
+		.seq_show = sched_partition_show,
+		.write = sched_partition_write,
+		.private = FILE_PARTITION_ROOT,
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.file_offset = offsetof(struct cpuset, partition_file),
+	},
+
+	{
+		.name = "cpus.subpartitions",
+		.seq_show = cpuset_common_seq_show,
+		.private = FILE_SUBPARTS_CPULIST,
+		.flags = CFTYPE_DEBUG,
+	},
+
+	{ }	/* terminate */
+};
+
+
+/*
+ *	cpuset_css_alloc - allocate a cpuset css
+ *	cgrp:	control group that the new cpuset will be part of
+ */
+
+static struct cgroup_subsys_state *
+cpuset_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+	struct cpuset *cs;
+
+	if (!parent_css)
+		return &top_cpuset.css;
+
+	cs = kzalloc(sizeof(*cs), GFP_KERNEL);
+	if (!cs)
+		return ERR_PTR(-ENOMEM);
+
+	if (alloc_cpumasks(cs, NULL)) {
+		kfree(cs);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	__set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
+	nodes_clear(cs->mems_allowed);
+	nodes_clear(cs->effective_mems);
+	fmeter_init(&cs->fmeter);
+	cs->relax_domain_level = -1;
+
+	/* Set CS_MEMORY_MIGRATE for default hierarchy */
+	if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys))
+		__set_bit(CS_MEMORY_MIGRATE, &cs->flags);
+
+	return &cs->css;
+}
+
+static int cpuset_css_online(struct cgroup_subsys_state *css)
+{
+	struct cpuset *cs = css_cs(css);
+	struct cpuset *parent = parent_cs(cs);
+	struct cpuset *tmp_cs;
+	struct cgroup_subsys_state *pos_css;
+
+	if (!parent)
+		return 0;
+
+	cpus_read_lock();
+	mutex_lock(&cpuset_mutex);
+
+	set_bit(CS_ONLINE, &cs->flags);
+	if (is_spread_page(parent))
+		set_bit(CS_SPREAD_PAGE, &cs->flags);
+	if (is_spread_slab(parent))
+		set_bit(CS_SPREAD_SLAB, &cs->flags);
+
+	cpuset_inc();
+
+	spin_lock_irq(&callback_lock);
+	if (is_in_v2_mode()) {
+		cpumask_copy(cs->effective_cpus, parent->effective_cpus);
+		cs->effective_mems = parent->effective_mems;
+		cs->use_parent_ecpus = true;
+		parent->child_ecpus_count++;
+	}
+
+	/*
+	 * For v2, clear CS_SCHED_LOAD_BALANCE if parent is isolated
+	 */
+	if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
+	    !is_sched_load_balance(parent))
+		clear_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
+
+	spin_unlock_irq(&callback_lock);
+
+	if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags))
+		goto out_unlock;
+
+	/*
+	 * Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is
+	 * set.  This flag handling is implemented in cgroup core for
+	 * historical reasons - the flag may be specified during mount.
+	 *
+	 * Currently, if any sibling cpusets have exclusive cpus or mem, we
+	 * refuse to clone the configuration - thereby refusing the task to
+	 * be entered, and as a result refusing the sys_unshare() or
+	 * clone() which initiated it.  If this becomes a problem for some
+	 * users who wish to allow that scenario, then this could be
+	 * changed to grant parent->cpus_allowed-sibling_cpus_exclusive
+	 * (and likewise for mems) to the new cgroup.
+	 */
+	rcu_read_lock();
+	cpuset_for_each_child(tmp_cs, pos_css, parent) {
+		if (is_mem_exclusive(tmp_cs) || is_cpu_exclusive(tmp_cs)) {
+			rcu_read_unlock();
+			goto out_unlock;
+		}
+	}
+	rcu_read_unlock();
+
+	spin_lock_irq(&callback_lock);
+	cs->mems_allowed = parent->mems_allowed;
+	cs->effective_mems = parent->mems_allowed;
+	cpumask_copy(cs->cpus_allowed, parent->cpus_allowed);
+	cpumask_copy(cs->effective_cpus, parent->cpus_allowed);
+	spin_unlock_irq(&callback_lock);
+out_unlock:
+	mutex_unlock(&cpuset_mutex);
+	cpus_read_unlock();
+	return 0;
+}
+
+/*
+ * If the cpuset being removed has its flag 'sched_load_balance'
+ * enabled, then simulate turning sched_load_balance off, which
+ * will call rebuild_sched_domains_locked(). That is not needed
+ * in the default hierarchy where only changes in partition
+ * will cause repartitioning.
+ *
+ * If the cpuset has the 'sched.partition' flag enabled, simulate
+ * turning 'sched.partition" off.
+ */
+
+static void cpuset_css_offline(struct cgroup_subsys_state *css)
+{
+	struct cpuset *cs = css_cs(css);
+
+	cpus_read_lock();
+	mutex_lock(&cpuset_mutex);
+
+	if (is_partition_valid(cs))
+		update_prstate(cs, 0);
+
+	if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
+	    is_sched_load_balance(cs))
+		update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
+
+	if (cs->use_parent_ecpus) {
+		struct cpuset *parent = parent_cs(cs);
+
+		cs->use_parent_ecpus = false;
+		parent->child_ecpus_count--;
+	}
+
+	cpuset_dec();
+	clear_bit(CS_ONLINE, &cs->flags);
+
+	mutex_unlock(&cpuset_mutex);
+	cpus_read_unlock();
+}
+
+static void cpuset_css_free(struct cgroup_subsys_state *css)
+{
+	struct cpuset *cs = css_cs(css);
+
+	free_cpuset(cs);
+}
+
+static void cpuset_bind(struct cgroup_subsys_state *root_css)
+{
+	mutex_lock(&cpuset_mutex);
+	spin_lock_irq(&callback_lock);
+
+	if (is_in_v2_mode()) {
+		cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask);
+		top_cpuset.mems_allowed = node_possible_map;
+	} else {
+		cpumask_copy(top_cpuset.cpus_allowed,
+			     top_cpuset.effective_cpus);
+		top_cpuset.mems_allowed = top_cpuset.effective_mems;
+	}
+
+	spin_unlock_irq(&callback_lock);
+	mutex_unlock(&cpuset_mutex);
+}
+
+/*
+ * In case the child is cloned into a cpuset different from its parent,
+ * additional checks are done to see if the move is allowed.
+ */
+static int cpuset_can_fork(struct task_struct *task, struct css_set *cset)
+{
+	struct cpuset *cs = css_cs(cset->subsys[cpuset_cgrp_id]);
+	bool same_cs;
+	int ret;
+
+	rcu_read_lock();
+	same_cs = (cs == task_cs(current));
+	rcu_read_unlock();
+
+	if (same_cs)
+		return 0;
+
+	lockdep_assert_held(&cgroup_mutex);
+	mutex_lock(&cpuset_mutex);
+
+	/* Check to see if task is allowed in the cpuset */
+	ret = cpuset_can_attach_check(cs);
+	if (ret)
+		goto out_unlock;
+
+	ret = task_can_attach(task);
+	if (ret)
+		goto out_unlock;
+
+	ret = security_task_setscheduler(task);
+	if (ret)
+		goto out_unlock;
+
+	/*
+	 * Mark attach is in progress.  This makes validate_change() fail
+	 * changes which zero cpus/mems_allowed.
+	 */
+	cs->attach_in_progress++;
+out_unlock:
+	mutex_unlock(&cpuset_mutex);
+	return ret;
+}
+
+static void cpuset_cancel_fork(struct task_struct *task, struct css_set *cset)
+{
+	struct cpuset *cs = css_cs(cset->subsys[cpuset_cgrp_id]);
+	bool same_cs;
+
+	rcu_read_lock();
+	same_cs = (cs == task_cs(current));
+	rcu_read_unlock();
+
+	if (same_cs)
+		return;
+
+	mutex_lock(&cpuset_mutex);
+	cs->attach_in_progress--;
+	if (!cs->attach_in_progress)
+		wake_up(&cpuset_attach_wq);
+	mutex_unlock(&cpuset_mutex);
+}
+
+/*
+ * Make sure the new task conform to the current state of its parent,
+ * which could have been changed by cpuset just after it inherits the
+ * state from the parent and before it sits on the cgroup's task list.
+ */
+static void cpuset_fork(struct task_struct *task)
+{
+	struct cpuset *cs;
+	bool same_cs;
+
+	rcu_read_lock();
+	cs = task_cs(task);
+	same_cs = (cs == task_cs(current));
+	rcu_read_unlock();
+
+	if (same_cs) {
+		if (cs == &top_cpuset)
+			return;
+
+		set_cpus_allowed_ptr(task, current->cpus_ptr);
+		task->mems_allowed = current->mems_allowed;
+		return;
+	}
+
+	/* CLONE_INTO_CGROUP */
+	mutex_lock(&cpuset_mutex);
+	guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
+	cpuset_attach_task(cs, task);
+
+	cs->attach_in_progress--;
+	if (!cs->attach_in_progress)
+		wake_up(&cpuset_attach_wq);
+
+	mutex_unlock(&cpuset_mutex);
+}
+
+struct cgroup_subsys cpuset_cgrp_subsys = {
+	.css_alloc	= cpuset_css_alloc,
+	.css_online	= cpuset_css_online,
+	.css_offline	= cpuset_css_offline,
+	.css_free	= cpuset_css_free,
+	.can_attach	= cpuset_can_attach,
+	.cancel_attach	= cpuset_cancel_attach,
+	.attach		= cpuset_attach,
+	.post_attach	= cpuset_post_attach,
+	.bind		= cpuset_bind,
+	.can_fork	= cpuset_can_fork,
+	.cancel_fork	= cpuset_cancel_fork,
+	.fork		= cpuset_fork,
+	.legacy_cftypes	= legacy_files,
+	.dfl_cftypes	= dfl_files,
+	.early_init	= true,
+	.threaded	= true,
+};
+
+/**
+ * cpuset_init - initialize cpusets at system boot
+ *
+ * Description: Initialize top_cpuset
+ **/
+
+int __init cpuset_init(void)
+{
+	BUG_ON(!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL));
+	BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL));
+	BUG_ON(!zalloc_cpumask_var(&top_cpuset.subparts_cpus, GFP_KERNEL));
+
+	cpumask_setall(top_cpuset.cpus_allowed);
+	nodes_setall(top_cpuset.mems_allowed);
+	cpumask_setall(top_cpuset.effective_cpus);
+	nodes_setall(top_cpuset.effective_mems);
+
+	fmeter_init(&top_cpuset.fmeter);
+	set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
+	top_cpuset.relax_domain_level = -1;
+
+	BUG_ON(!alloc_cpumask_var(&cpus_attach, GFP_KERNEL));
+
+	return 0;
+}
+
+/*
+ * If CPU and/or memory hotplug handlers, below, unplug any CPUs
+ * or memory nodes, we need to walk over the cpuset hierarchy,
+ * removing that CPU or node from all cpusets.  If this removes the
+ * last CPU or node from a cpuset, then move the tasks in the empty
+ * cpuset to its next-highest non-empty parent.
+ */
+static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
+{
+	struct cpuset *parent;
+
+	/*
+	 * Find its next-highest non-empty parent, (top cpuset
+	 * has online cpus, so can't be empty).
+	 */
+	parent = parent_cs(cs);
+	while (cpumask_empty(parent->cpus_allowed) ||
+			nodes_empty(parent->mems_allowed))
+		parent = parent_cs(parent);
+
+	if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) {
+		pr_err("cpuset: failed to transfer tasks out of empty cpuset ");
+		pr_cont_cgroup_name(cs->css.cgroup);
+		pr_cont("\n");
+	}
+}
+
+static void
+hotplug_update_tasks_legacy(struct cpuset *cs,
+			    struct cpumask *new_cpus, nodemask_t *new_mems,
+			    bool cpus_updated, bool mems_updated)
+{
+	bool is_empty;
+
+	spin_lock_irq(&callback_lock);
+	cpumask_copy(cs->cpus_allowed, new_cpus);
+	cpumask_copy(cs->effective_cpus, new_cpus);
+	cs->mems_allowed = *new_mems;
+	cs->effective_mems = *new_mems;
+	spin_unlock_irq(&callback_lock);
+
+	/*
+	 * Don't call update_tasks_cpumask() if the cpuset becomes empty,
+	 * as the tasks will be migrated to an ancestor.
+	 */
+	if (cpus_updated && !cpumask_empty(cs->cpus_allowed))
+		update_tasks_cpumask(cs, new_cpus);
+	if (mems_updated && !nodes_empty(cs->mems_allowed))
+		update_tasks_nodemask(cs);
+
+	is_empty = cpumask_empty(cs->cpus_allowed) ||
+		   nodes_empty(cs->mems_allowed);
+
+	mutex_unlock(&cpuset_mutex);
+
+	/*
+	 * Move tasks to the nearest ancestor with execution resources,
+	 * This is full cgroup operation which will also call back into
+	 * cpuset. Should be done outside any lock.
+	 */
+	if (is_empty)
+		remove_tasks_in_empty_cpuset(cs);
+
+	mutex_lock(&cpuset_mutex);
+}
+
+static void
+hotplug_update_tasks(struct cpuset *cs,
+		     struct cpumask *new_cpus, nodemask_t *new_mems,
+		     bool cpus_updated, bool mems_updated)
+{
+	/* A partition root is allowed to have empty effective cpus */
+	if (cpumask_empty(new_cpus) && !is_partition_valid(cs))
+		cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus);
+	if (nodes_empty(*new_mems))
+		*new_mems = parent_cs(cs)->effective_mems;
+
+	spin_lock_irq(&callback_lock);
+	cpumask_copy(cs->effective_cpus, new_cpus);
+	cs->effective_mems = *new_mems;
+	spin_unlock_irq(&callback_lock);
+
+	if (cpus_updated)
+		update_tasks_cpumask(cs, new_cpus);
+	if (mems_updated)
+		update_tasks_nodemask(cs);
+}
+
+static bool force_rebuild;
+
+void cpuset_force_rebuild(void)
+{
+	force_rebuild = true;
+}
+
+/**
+ * cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug
+ * @cs: cpuset in interest
+ * @tmp: the tmpmasks structure pointer
+ *
+ * Compare @cs's cpu and mem masks against top_cpuset and if some have gone
+ * offline, update @cs accordingly.  If @cs ends up with no CPU or memory,
+ * all its tasks are moved to the nearest ancestor with both resources.
+ */
+static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
+{
+	static cpumask_t new_cpus;
+	static nodemask_t new_mems;
+	bool cpus_updated;
+	bool mems_updated;
+	struct cpuset *parent;
+retry:
+	wait_event(cpuset_attach_wq, cs->attach_in_progress == 0);
+
+	mutex_lock(&cpuset_mutex);
+
+	/*
+	 * We have raced with task attaching. We wait until attaching
+	 * is finished, so we won't attach a task to an empty cpuset.
+	 */
+	if (cs->attach_in_progress) {
+		mutex_unlock(&cpuset_mutex);
+		goto retry;
+	}
+
+	parent = parent_cs(cs);
+	compute_effective_cpumask(&new_cpus, cs, parent);
+	nodes_and(new_mems, cs->mems_allowed, parent->effective_mems);
+
+	if (cs->nr_subparts_cpus)
+		/*
+		 * Make sure that CPUs allocated to child partitions
+		 * do not show up in effective_cpus.
+		 */
+		cpumask_andnot(&new_cpus, &new_cpus, cs->subparts_cpus);
+
+	if (!tmp || !cs->partition_root_state)
+		goto update_tasks;
+
+	/*
+	 * In the unlikely event that a partition root has empty
+	 * effective_cpus with tasks, we will have to invalidate child
+	 * partitions, if present, by setting nr_subparts_cpus to 0 to
+	 * reclaim their cpus.
+	 */
+	if (cs->nr_subparts_cpus && is_partition_valid(cs) &&
+	    cpumask_empty(&new_cpus) && partition_is_populated(cs, NULL)) {
+		spin_lock_irq(&callback_lock);
+		cs->nr_subparts_cpus = 0;
+		cpumask_clear(cs->subparts_cpus);
+		spin_unlock_irq(&callback_lock);
+		compute_effective_cpumask(&new_cpus, cs, parent);
+	}
+
+	/*
+	 * Force the partition to become invalid if either one of
+	 * the following conditions hold:
+	 * 1) empty effective cpus but not valid empty partition.
+	 * 2) parent is invalid or doesn't grant any cpus to child
+	 *    partitions.
+	 */
+	if (is_partition_valid(cs) && (!parent->nr_subparts_cpus ||
+	   (cpumask_empty(&new_cpus) && partition_is_populated(cs, NULL)))) {
+		int old_prs, parent_prs;
+
+		update_parent_subparts_cpumask(cs, partcmd_disable, NULL, tmp);
+		if (cs->nr_subparts_cpus) {
+			spin_lock_irq(&callback_lock);
+			cs->nr_subparts_cpus = 0;
+			cpumask_clear(cs->subparts_cpus);
+			spin_unlock_irq(&callback_lock);
+			compute_effective_cpumask(&new_cpus, cs, parent);
+		}
+
+		old_prs = cs->partition_root_state;
+		parent_prs = parent->partition_root_state;
+		if (is_partition_valid(cs)) {
+			spin_lock_irq(&callback_lock);
+			make_partition_invalid(cs);
+			spin_unlock_irq(&callback_lock);
+			if (is_prs_invalid(parent_prs))
+				WRITE_ONCE(cs->prs_err, PERR_INVPARENT);
+			else if (!parent_prs)
+				WRITE_ONCE(cs->prs_err, PERR_NOTPART);
+			else
+				WRITE_ONCE(cs->prs_err, PERR_HOTPLUG);
+			notify_partition_change(cs, old_prs);
+		}
+		cpuset_force_rebuild();
+	}
+
+	/*
+	 * On the other hand, an invalid partition root may be transitioned
+	 * back to a regular one.
+	 */
+	else if (is_partition_valid(parent) && is_partition_invalid(cs)) {
+		update_parent_subparts_cpumask(cs, partcmd_update, NULL, tmp);
+		if (is_partition_valid(cs))
+			cpuset_force_rebuild();
+	}
+
+update_tasks:
+	cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus);
+	mems_updated = !nodes_equal(new_mems, cs->effective_mems);
+
+	if (mems_updated)
+		check_insane_mems_config(&new_mems);
+
+	if (is_in_v2_mode())
+		hotplug_update_tasks(cs, &new_cpus, &new_mems,
+				     cpus_updated, mems_updated);
+	else
+		hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems,
+					    cpus_updated, mems_updated);
+
+	mutex_unlock(&cpuset_mutex);
+}
+
+/**
+ * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset
+ *
+ * This function is called after either CPU or memory configuration has
+ * changed and updates cpuset accordingly.  The top_cpuset is always
+ * synchronized to cpu_active_mask and N_MEMORY, which is necessary in
+ * order to make cpusets transparent (of no affect) on systems that are
+ * actively using CPU hotplug but making no active use of cpusets.
+ *
+ * Non-root cpusets are only affected by offlining.  If any CPUs or memory
+ * nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on
+ * all descendants.
+ *
+ * Note that CPU offlining during suspend is ignored.  We don't modify
+ * cpusets across suspend/resume cycles at all.
+ */
+static void cpuset_hotplug_workfn(struct work_struct *work)
+{
+	static cpumask_t new_cpus;
+	static nodemask_t new_mems;
+	bool cpus_updated, mems_updated;
+	bool on_dfl = is_in_v2_mode();
+	struct tmpmasks tmp, *ptmp = NULL;
+
+	if (on_dfl && !alloc_cpumasks(NULL, &tmp))
+		ptmp = &tmp;
+
+	mutex_lock(&cpuset_mutex);
+
+	/* fetch the available cpus/mems and find out which changed how */
+	cpumask_copy(&new_cpus, cpu_active_mask);
+	new_mems = node_states[N_MEMORY];
+
+	/*
+	 * If subparts_cpus is populated, it is likely that the check below
+	 * will produce a false positive on cpus_updated when the cpu list
+	 * isn't changed. It is extra work, but it is better to be safe.
+	 */
+	cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus);
+	mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);
+
+	/*
+	 * In the rare case that hotplug removes all the cpus in subparts_cpus,
+	 * we assumed that cpus are updated.
+	 */
+	if (!cpus_updated && top_cpuset.nr_subparts_cpus)
+		cpus_updated = true;
+
+	/* synchronize cpus_allowed to cpu_active_mask */
+	if (cpus_updated) {
+		spin_lock_irq(&callback_lock);
+		if (!on_dfl)
+			cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
+		/*
+		 * Make sure that CPUs allocated to child partitions
+		 * do not show up in effective_cpus. If no CPU is left,
+		 * we clear the subparts_cpus & let the child partitions
+		 * fight for the CPUs again.
+		 */
+		if (top_cpuset.nr_subparts_cpus) {
+			if (cpumask_subset(&new_cpus,
+					   top_cpuset.subparts_cpus)) {
+				top_cpuset.nr_subparts_cpus = 0;
+				cpumask_clear(top_cpuset.subparts_cpus);
+			} else {
+				cpumask_andnot(&new_cpus, &new_cpus,
+					       top_cpuset.subparts_cpus);
+			}
+		}
+		cpumask_copy(top_cpuset.effective_cpus, &new_cpus);
+		spin_unlock_irq(&callback_lock);
+		/* we don't mess with cpumasks of tasks in top_cpuset */
+	}
+
+	/* synchronize mems_allowed to N_MEMORY */
+	if (mems_updated) {
+		spin_lock_irq(&callback_lock);
+		if (!on_dfl)
+			top_cpuset.mems_allowed = new_mems;
+		top_cpuset.effective_mems = new_mems;
+		spin_unlock_irq(&callback_lock);
+		update_tasks_nodemask(&top_cpuset);
+	}
+
+	mutex_unlock(&cpuset_mutex);
+
+	/* if cpus or mems changed, we need to propagate to descendants */
+	if (cpus_updated || mems_updated) {
+		struct cpuset *cs;
+		struct cgroup_subsys_state *pos_css;
+
+		rcu_read_lock();
+		cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
+			if (cs == &top_cpuset || !css_tryget_online(&cs->css))
+				continue;
+			rcu_read_unlock();
+
+			cpuset_hotplug_update_tasks(cs, ptmp);
+
+			rcu_read_lock();
+			css_put(&cs->css);
+		}
+		rcu_read_unlock();
+	}
+
+	/* rebuild sched domains if cpus_allowed has changed */
+	if (cpus_updated || force_rebuild) {
+		force_rebuild = false;
+		rebuild_sched_domains();
+	}
+
+	free_cpumasks(NULL, ptmp);
+}
+
+void cpuset_update_active_cpus(void)
+{
+	/*
+	 * We're inside cpu hotplug critical region which usually nests
+	 * inside cgroup synchronization.  Bounce actual hotplug processing
+	 * to a work item to avoid reverse locking order.
+	 */
+	schedule_work(&cpuset_hotplug_work);
+}
+
+void cpuset_wait_for_hotplug(void)
+{
+	flush_work(&cpuset_hotplug_work);
+}
+
+/*
+ * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY].
+ * Call this routine anytime after node_states[N_MEMORY] changes.
+ * See cpuset_update_active_cpus() for CPU hotplug handling.
+ */
+static int cpuset_track_online_nodes(struct notifier_block *self,
+				unsigned long action, void *arg)
+{
+	schedule_work(&cpuset_hotplug_work);
+	return NOTIFY_OK;
+}
+
+static struct notifier_block cpuset_track_online_nodes_nb = {
+	.notifier_call = cpuset_track_online_nodes,
+	.priority = 10,		/* ??! */
+};
+
+/**
+ * cpuset_init_smp - initialize cpus_allowed
+ *
+ * Description: Finish top cpuset after cpu, node maps are initialized
+ */
+void __init cpuset_init_smp(void)
+{
+	/*
+	 * cpus_allowd/mems_allowed set to v2 values in the initial
+	 * cpuset_bind() call will be reset to v1 values in another
+	 * cpuset_bind() call when v1 cpuset is mounted.
+	 */
+	top_cpuset.old_mems_allowed = top_cpuset.mems_allowed;
+
+	cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask);
+	top_cpuset.effective_mems = node_states[N_MEMORY];
+
+	register_hotmemory_notifier(&cpuset_track_online_nodes_nb);
+
+	cpuset_migrate_mm_wq = alloc_ordered_workqueue("cpuset_migrate_mm", 0);
+	BUG_ON(!cpuset_migrate_mm_wq);
+}
+
+/**
+ * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
+ * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
+ * @pmask: pointer to struct cpumask variable to receive cpus_allowed set.
+ *
+ * Description: Returns the cpumask_var_t cpus_allowed of the cpuset
+ * attached to the specified @tsk.  Guaranteed to return some non-empty
+ * subset of cpu_online_mask, even if this means going outside the
+ * tasks cpuset.
+ **/
+
+void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&callback_lock, flags);
+	guarantee_online_cpus(tsk, pmask);
+	spin_unlock_irqrestore(&callback_lock, flags);
+}
+
+/**
+ * cpuset_cpus_allowed_fallback - final fallback before complete catastrophe.
+ * @tsk: pointer to task_struct with which the scheduler is struggling
+ *
+ * Description: In the case that the scheduler cannot find an allowed cpu in
+ * tsk->cpus_allowed, we fall back to task_cs(tsk)->cpus_allowed. In legacy
+ * mode however, this value is the same as task_cs(tsk)->effective_cpus,
+ * which will not contain a sane cpumask during cases such as cpu hotplugging.
+ * This is the absolute last resort for the scheduler and it is only used if
+ * _every_ other avenue has been traveled.
+ *
+ * Returns true if the affinity of @tsk was changed, false otherwise.
+ **/
+
+bool cpuset_cpus_allowed_fallback(struct task_struct *tsk)
+{
+	const struct cpumask *possible_mask = task_cpu_possible_mask(tsk);
+	const struct cpumask *cs_mask;
+	bool changed = false;
+
+	rcu_read_lock();
+	cs_mask = task_cs(tsk)->cpus_allowed;
+	if (is_in_v2_mode() && cpumask_subset(cs_mask, possible_mask)) {
+		do_set_cpus_allowed(tsk, cs_mask);
+		changed = true;
+	}
+	rcu_read_unlock();
+
+	/*
+	 * We own tsk->cpus_allowed, nobody can change it under us.
+	 *
+	 * But we used cs && cs->cpus_allowed lockless and thus can
+	 * race with cgroup_attach_task() or update_cpumask() and get
+	 * the wrong tsk->cpus_allowed. However, both cases imply the
+	 * subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr()
+	 * which takes task_rq_lock().
+	 *
+	 * If we are called after it dropped the lock we must see all
+	 * changes in tsk_cs()->cpus_allowed. Otherwise we can temporary
+	 * set any mask even if it is not right from task_cs() pov,
+	 * the pending set_cpus_allowed_ptr() will fix things.
+	 *
+	 * select_fallback_rq() will fix things ups and set cpu_possible_mask
+	 * if required.
+	 */
+	return changed;
+}
+
+void __init cpuset_init_current_mems_allowed(void)
+{
+	nodes_setall(current->mems_allowed);
+}
+
+/**
+ * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
+ * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
+ *
+ * Description: Returns the nodemask_t mems_allowed of the cpuset
+ * attached to the specified @tsk.  Guaranteed to return some non-empty
+ * subset of node_states[N_MEMORY], even if this means going outside the
+ * tasks cpuset.
+ **/
+
+nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
+{
+	nodemask_t mask;
+	unsigned long flags;
+
+	spin_lock_irqsave(&callback_lock, flags);
+	rcu_read_lock();
+	guarantee_online_mems(task_cs(tsk), &mask);
+	rcu_read_unlock();
+	spin_unlock_irqrestore(&callback_lock, flags);
+
+	return mask;
+}
+
+/**
+ * cpuset_nodemask_valid_mems_allowed - check nodemask vs. current mems_allowed
+ * @nodemask: the nodemask to be checked
+ *
+ * Are any of the nodes in the nodemask allowed in current->mems_allowed?
+ */
+int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
+{
+	return nodes_intersects(*nodemask, current->mems_allowed);
+}
+
+/*
+ * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or
+ * mem_hardwall ancestor to the specified cpuset.  Call holding
+ * callback_lock.  If no ancestor is mem_exclusive or mem_hardwall
+ * (an unusual configuration), then returns the root cpuset.
+ */
+static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
+{
+	while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && parent_cs(cs))
+		cs = parent_cs(cs);
+	return cs;
+}
+
+/*
+ * __cpuset_node_allowed - Can we allocate on a memory node?
+ * @node: is this an allowed node?
+ * @gfp_mask: memory allocation flags
+ *
+ * If we're in interrupt, yes, we can always allocate.  If @node is set in
+ * current's mems_allowed, yes.  If it's not a __GFP_HARDWALL request and this
+ * node is set in the nearest hardwalled cpuset ancestor to current's cpuset,
+ * yes.  If current has access to memory reserves as an oom victim, yes.
+ * Otherwise, no.
+ *
+ * GFP_USER allocations are marked with the __GFP_HARDWALL bit,
+ * and do not allow allocations outside the current tasks cpuset
+ * unless the task has been OOM killed.
+ * GFP_KERNEL allocations are not so marked, so can escape to the
+ * nearest enclosing hardwalled ancestor cpuset.
+ *
+ * Scanning up parent cpusets requires callback_lock.  The
+ * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
+ * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
+ * current tasks mems_allowed came up empty on the first pass over
+ * the zonelist.  So only GFP_KERNEL allocations, if all nodes in the
+ * cpuset are short of memory, might require taking the callback_lock.
+ *
+ * The first call here from mm/page_alloc:get_page_from_freelist()
+ * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
+ * so no allocation on a node outside the cpuset is allowed (unless
+ * in interrupt, of course).
+ *
+ * The second pass through get_page_from_freelist() doesn't even call
+ * here for GFP_ATOMIC calls.  For those calls, the __alloc_pages()
+ * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
+ * in alloc_flags.  That logic and the checks below have the combined
+ * affect that:
+ *	in_interrupt - any node ok (current task context irrelevant)
+ *	GFP_ATOMIC   - any node ok
+ *	tsk_is_oom_victim   - any node ok
+ *	GFP_KERNEL   - any node in enclosing hardwalled cpuset ok
+ *	GFP_USER     - only nodes in current tasks mems allowed ok.
+ */
+bool __cpuset_node_allowed(int node, gfp_t gfp_mask)
+{
+	struct cpuset *cs;		/* current cpuset ancestors */
+	bool allowed;			/* is allocation in zone z allowed? */
+	unsigned long flags;
+
+	if (in_interrupt())
+		return true;
+	if (node_isset(node, current->mems_allowed))
+		return true;
+	/*
+	 * Allow tasks that have access to memory reserves because they have
+	 * been OOM killed to get memory anywhere.
+	 */
+	if (unlikely(tsk_is_oom_victim(current)))
+		return true;
+	if (gfp_mask & __GFP_HARDWALL)	/* If hardwall request, stop here */
+		return false;
+
+	if (current->flags & PF_EXITING) /* Let dying task have memory */
+		return true;
+
+	/* Not hardwall and node outside mems_allowed: scan up cpusets */
+	spin_lock_irqsave(&callback_lock, flags);
+
+	rcu_read_lock();
+	cs = nearest_hardwall_ancestor(task_cs(current));
+	allowed = node_isset(node, cs->mems_allowed);
+	rcu_read_unlock();
+
+	spin_unlock_irqrestore(&callback_lock, flags);
+	return allowed;
+}
+
+/**
+ * cpuset_mem_spread_node() - On which node to begin search for a file page
+ * cpuset_slab_spread_node() - On which node to begin search for a slab page
+ *
+ * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
+ * tasks in a cpuset with is_spread_page or is_spread_slab set),
+ * and if the memory allocation used cpuset_mem_spread_node()
+ * to determine on which node to start looking, as it will for
+ * certain page cache or slab cache pages such as used for file
+ * system buffers and inode caches, then instead of starting on the
+ * local node to look for a free page, rather spread the starting
+ * node around the tasks mems_allowed nodes.
+ *
+ * We don't have to worry about the returned node being offline
+ * because "it can't happen", and even if it did, it would be ok.
+ *
+ * The routines calling guarantee_online_mems() are careful to
+ * only set nodes in task->mems_allowed that are online.  So it
+ * should not be possible for the following code to return an
+ * offline node.  But if it did, that would be ok, as this routine
+ * is not returning the node where the allocation must be, only
+ * the node where the search should start.  The zonelist passed to
+ * __alloc_pages() will include all nodes.  If the slab allocator
+ * is passed an offline node, it will fall back to the local node.
+ * See kmem_cache_alloc_node().
+ */
+
+static int cpuset_spread_node(int *rotor)
+{
+	return *rotor = next_node_in(*rotor, current->mems_allowed);
+}
+
+int cpuset_mem_spread_node(void)
+{
+	if (current->cpuset_mem_spread_rotor == NUMA_NO_NODE)
+		current->cpuset_mem_spread_rotor =
+			node_random(&current->mems_allowed);
+
+	return cpuset_spread_node(&current->cpuset_mem_spread_rotor);
+}
+
+int cpuset_slab_spread_node(void)
+{
+	if (current->cpuset_slab_spread_rotor == NUMA_NO_NODE)
+		current->cpuset_slab_spread_rotor =
+			node_random(&current->mems_allowed);
+
+	return cpuset_spread_node(&current->cpuset_slab_spread_rotor);
+}
+
+EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
+
+/**
+ * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's?
+ * @tsk1: pointer to task_struct of some task.
+ * @tsk2: pointer to task_struct of some other task.
+ *
+ * Description: Return true if @tsk1's mems_allowed intersects the
+ * mems_allowed of @tsk2.  Used by the OOM killer to determine if
+ * one of the task's memory usage might impact the memory available
+ * to the other.
+ **/
+
+int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
+				   const struct task_struct *tsk2)
+{
+	return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
+}
+
+/**
+ * cpuset_print_current_mems_allowed - prints current's cpuset and mems_allowed
+ *
+ * Description: Prints current's name, cpuset name, and cached copy of its
+ * mems_allowed to the kernel log.
+ */
+void cpuset_print_current_mems_allowed(void)
+{
+	struct cgroup *cgrp;
+
+	rcu_read_lock();
+
+	cgrp = task_cs(current)->css.cgroup;
+	pr_cont(",cpuset=");
+	pr_cont_cgroup_name(cgrp);
+	pr_cont(",mems_allowed=%*pbl",
+		nodemask_pr_args(&current->mems_allowed));
+
+	rcu_read_unlock();
+}
+
+/*
+ * Collection of memory_pressure is suppressed unless
+ * this flag is enabled by writing "1" to the special
+ * cpuset file 'memory_pressure_enabled' in the root cpuset.
+ */
+
+int cpuset_memory_pressure_enabled __read_mostly;
+
+/*
+ * __cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
+ *
+ * Keep a running average of the rate of synchronous (direct)
+ * page reclaim efforts initiated by tasks in each cpuset.
+ *
+ * This represents the rate at which some task in the cpuset
+ * ran low on memory on all nodes it was allowed to use, and
+ * had to enter the kernels page reclaim code in an effort to
+ * create more free memory by tossing clean pages or swapping
+ * or writing dirty pages.
+ *
+ * Display to user space in the per-cpuset read-only file
+ * "memory_pressure".  Value displayed is an integer
+ * representing the recent rate of entry into the synchronous
+ * (direct) page reclaim by any task attached to the cpuset.
+ */
+
+void __cpuset_memory_pressure_bump(void)
+{
+	rcu_read_lock();
+	fmeter_markevent(&task_cs(current)->fmeter);
+	rcu_read_unlock();
+}
+
+#ifdef CONFIG_PROC_PID_CPUSET
+/*
+ * proc_cpuset_show()
+ *  - Print tasks cpuset path into seq_file.
+ *  - Used for /proc/<pid>/cpuset.
+ *  - No need to task_lock(tsk) on this tsk->cpuset reference, as it
+ *    doesn't really matter if tsk->cpuset changes after we read it,
+ *    and we take cpuset_mutex, keeping cpuset_attach() from changing it
+ *    anyway.
+ */
+int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
+		     struct pid *pid, struct task_struct *tsk)
+{
+	char *buf;
+	struct cgroup_subsys_state *css;
+	int retval;
+
+	retval = -ENOMEM;
+	buf = kmalloc(PATH_MAX, GFP_KERNEL);
+	if (!buf)
+		goto out;
+
+	css = task_get_css(tsk, cpuset_cgrp_id);
+	retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
+				current->nsproxy->cgroup_ns);
+	css_put(css);
+	if (retval >= PATH_MAX)
+		retval = -ENAMETOOLONG;
+	if (retval < 0)
+		goto out_free;
+	seq_puts(m, buf);
+	seq_putc(m, '\n');
+	retval = 0;
+out_free:
+	kfree(buf);
+out:
+	return retval;
+}
+#endif /* CONFIG_PROC_PID_CPUSET */
+
+/* Display task mems_allowed in /proc/<pid>/status file. */
+void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task)
+{
+	seq_printf(m, "Mems_allowed:\t%*pb\n",
+		   nodemask_pr_args(&task->mems_allowed));
+	seq_printf(m, "Mems_allowed_list:\t%*pbl\n",
+		   nodemask_pr_args(&task->mems_allowed));
+}
diff --git a/kernel/cgroup/debug.c b/kernel/cgroup/debug.c
new file mode 100644
index 000000000..80aa3f027
--- /dev/null
+++ b/kernel/cgroup/debug.c
@@ -0,0 +1,381 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Debug controller
+ *
+ * WARNING: This controller is for cgroup core debugging only.
+ * Its interfaces are unstable and subject to changes at any time.
+ */
+#include <linux/ctype.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+
+#include "cgroup-internal.h"
+
+static struct cgroup_subsys_state *
+debug_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+	struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL);
+
+	if (!css)
+		return ERR_PTR(-ENOMEM);
+
+	return css;
+}
+
+static void debug_css_free(struct cgroup_subsys_state *css)
+{
+	kfree(css);
+}
+
+/*
+ * debug_taskcount_read - return the number of tasks in a cgroup.
+ * @cgrp: the cgroup in question
+ */
+static u64 debug_taskcount_read(struct cgroup_subsys_state *css,
+				struct cftype *cft)
+{
+	return cgroup_task_count(css->cgroup);
+}
+
+static int current_css_set_read(struct seq_file *seq, void *v)
+{
+	struct kernfs_open_file *of = seq->private;
+	struct css_set *cset;
+	struct cgroup_subsys *ss;
+	struct cgroup_subsys_state *css;
+	int i, refcnt;
+
+	if (!cgroup_kn_lock_live(of->kn, false))
+		return -ENODEV;
+
+	spin_lock_irq(&css_set_lock);
+	rcu_read_lock();
+	cset = task_css_set(current);
+	refcnt = refcount_read(&cset->refcount);
+	seq_printf(seq, "css_set %pK %d", cset, refcnt);
+	if (refcnt > cset->nr_tasks)
+		seq_printf(seq, " +%d", refcnt - cset->nr_tasks);
+	seq_puts(seq, "\n");
+
+	/*
+	 * Print the css'es stored in the current css_set.
+	 */
+	for_each_subsys(ss, i) {
+		css = cset->subsys[ss->id];
+		if (!css)
+			continue;
+		seq_printf(seq, "%2d: %-4s\t- %p[%d]\n", ss->id, ss->name,
+			  css, css->id);
+	}
+	rcu_read_unlock();
+	spin_unlock_irq(&css_set_lock);
+	cgroup_kn_unlock(of->kn);
+	return 0;
+}
+
+static u64 current_css_set_refcount_read(struct cgroup_subsys_state *css,
+					 struct cftype *cft)
+{
+	u64 count;
+
+	rcu_read_lock();
+	count = refcount_read(&task_css_set(current)->refcount);
+	rcu_read_unlock();
+	return count;
+}
+
+static int current_css_set_cg_links_read(struct seq_file *seq, void *v)
+{
+	struct cgrp_cset_link *link;
+	struct css_set *cset;
+	char *name_buf;
+
+	name_buf = kmalloc(NAME_MAX + 1, GFP_KERNEL);
+	if (!name_buf)
+		return -ENOMEM;
+
+	spin_lock_irq(&css_set_lock);
+	rcu_read_lock();
+	cset = task_css_set(current);
+	list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
+		struct cgroup *c = link->cgrp;
+
+		cgroup_name(c, name_buf, NAME_MAX + 1);
+		seq_printf(seq, "Root %d group %s\n",
+			   c->root->hierarchy_id, name_buf);
+	}
+	rcu_read_unlock();
+	spin_unlock_irq(&css_set_lock);
+	kfree(name_buf);
+	return 0;
+}
+
+#define MAX_TASKS_SHOWN_PER_CSS 25
+static int cgroup_css_links_read(struct seq_file *seq, void *v)
+{
+	struct cgroup_subsys_state *css = seq_css(seq);
+	struct cgrp_cset_link *link;
+	int dead_cnt = 0, extra_refs = 0, threaded_csets = 0;
+
+	spin_lock_irq(&css_set_lock);
+
+	list_for_each_entry(link, &css->cgroup->cset_links, cset_link) {
+		struct css_set *cset = link->cset;
+		struct task_struct *task;
+		int count = 0;
+		int refcnt = refcount_read(&cset->refcount);
+
+		/*
+		 * Print out the proc_cset and threaded_cset relationship
+		 * and highlight difference between refcount and task_count.
+		 */
+		seq_printf(seq, "css_set %pK", cset);
+		if (rcu_dereference_protected(cset->dom_cset, 1) != cset) {
+			threaded_csets++;
+			seq_printf(seq, "=>%pK", cset->dom_cset);
+		}
+		if (!list_empty(&cset->threaded_csets)) {
+			struct css_set *tcset;
+			int idx = 0;
+
+			list_for_each_entry(tcset, &cset->threaded_csets,
+					    threaded_csets_node) {
+				seq_puts(seq, idx ? "," : "<=");
+				seq_printf(seq, "%pK", tcset);
+				idx++;
+			}
+		} else {
+			seq_printf(seq, " %d", refcnt);
+			if (refcnt - cset->nr_tasks > 0) {
+				int extra = refcnt - cset->nr_tasks;
+
+				seq_printf(seq, " +%d", extra);
+				/*
+				 * Take out the one additional reference in
+				 * init_css_set.
+				 */
+				if (cset == &init_css_set)
+					extra--;
+				extra_refs += extra;
+			}
+		}
+		seq_puts(seq, "\n");
+
+		list_for_each_entry(task, &cset->tasks, cg_list) {
+			if (count++ <= MAX_TASKS_SHOWN_PER_CSS)
+				seq_printf(seq, "  task %d\n",
+					   task_pid_vnr(task));
+		}
+
+		list_for_each_entry(task, &cset->mg_tasks, cg_list) {
+			if (count++ <= MAX_TASKS_SHOWN_PER_CSS)
+				seq_printf(seq, "  task %d\n",
+					   task_pid_vnr(task));
+		}
+		/* show # of overflowed tasks */
+		if (count > MAX_TASKS_SHOWN_PER_CSS)
+			seq_printf(seq, "  ... (%d)\n",
+				   count - MAX_TASKS_SHOWN_PER_CSS);
+
+		if (cset->dead) {
+			seq_puts(seq, "    [dead]\n");
+			dead_cnt++;
+		}
+
+		WARN_ON(count != cset->nr_tasks);
+	}
+	spin_unlock_irq(&css_set_lock);
+
+	if (!dead_cnt && !extra_refs && !threaded_csets)
+		return 0;
+
+	seq_puts(seq, "\n");
+	if (threaded_csets)
+		seq_printf(seq, "threaded css_sets = %d\n", threaded_csets);
+	if (extra_refs)
+		seq_printf(seq, "extra references = %d\n", extra_refs);
+	if (dead_cnt)
+		seq_printf(seq, "dead css_sets = %d\n", dead_cnt);
+
+	return 0;
+}
+
+static int cgroup_subsys_states_read(struct seq_file *seq, void *v)
+{
+	struct kernfs_open_file *of = seq->private;
+	struct cgroup *cgrp;
+	struct cgroup_subsys *ss;
+	struct cgroup_subsys_state *css;
+	char pbuf[16];
+	int i;
+
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENODEV;
+
+	for_each_subsys(ss, i) {
+		css = rcu_dereference_check(cgrp->subsys[ss->id], true);
+		if (!css)
+			continue;
+
+		pbuf[0] = '\0';
+
+		/* Show the parent CSS if applicable*/
+		if (css->parent)
+			snprintf(pbuf, sizeof(pbuf) - 1, " P=%d",
+				 css->parent->id);
+		seq_printf(seq, "%2d: %-4s\t- %p[%d] %d%s\n", ss->id, ss->name,
+			  css, css->id,
+			  atomic_read(&css->online_cnt), pbuf);
+	}
+
+	cgroup_kn_unlock(of->kn);
+	return 0;
+}
+
+static void cgroup_masks_read_one(struct seq_file *seq, const char *name,
+				  u16 mask)
+{
+	struct cgroup_subsys *ss;
+	int ssid;
+	bool first = true;
+
+	seq_printf(seq, "%-17s: ", name);
+	for_each_subsys(ss, ssid) {
+		if (!(mask & (1 << ssid)))
+			continue;
+		if (!first)
+			seq_puts(seq, ", ");
+		seq_puts(seq, ss->name);
+		first = false;
+	}
+	seq_putc(seq, '\n');
+}
+
+static int cgroup_masks_read(struct seq_file *seq, void *v)
+{
+	struct kernfs_open_file *of = seq->private;
+	struct cgroup *cgrp;
+
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENODEV;
+
+	cgroup_masks_read_one(seq, "subtree_control", cgrp->subtree_control);
+	cgroup_masks_read_one(seq, "subtree_ss_mask", cgrp->subtree_ss_mask);
+
+	cgroup_kn_unlock(of->kn);
+	return 0;
+}
+
+static u64 releasable_read(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+	return (!cgroup_is_populated(css->cgroup) &&
+		!css_has_online_children(&css->cgroup->self));
+}
+
+static struct cftype debug_legacy_files[] =  {
+	{
+		.name = "taskcount",
+		.read_u64 = debug_taskcount_read,
+	},
+
+	{
+		.name = "current_css_set",
+		.seq_show = current_css_set_read,
+		.flags = CFTYPE_ONLY_ON_ROOT,
+	},
+
+	{
+		.name = "current_css_set_refcount",
+		.read_u64 = current_css_set_refcount_read,
+		.flags = CFTYPE_ONLY_ON_ROOT,
+	},
+
+	{
+		.name = "current_css_set_cg_links",
+		.seq_show = current_css_set_cg_links_read,
+		.flags = CFTYPE_ONLY_ON_ROOT,
+	},
+
+	{
+		.name = "cgroup_css_links",
+		.seq_show = cgroup_css_links_read,
+	},
+
+	{
+		.name = "cgroup_subsys_states",
+		.seq_show = cgroup_subsys_states_read,
+	},
+
+	{
+		.name = "cgroup_masks",
+		.seq_show = cgroup_masks_read,
+	},
+
+	{
+		.name = "releasable",
+		.read_u64 = releasable_read,
+	},
+
+	{ }	/* terminate */
+};
+
+static struct cftype debug_files[] =  {
+	{
+		.name = "taskcount",
+		.read_u64 = debug_taskcount_read,
+	},
+
+	{
+		.name = "current_css_set",
+		.seq_show = current_css_set_read,
+		.flags = CFTYPE_ONLY_ON_ROOT,
+	},
+
+	{
+		.name = "current_css_set_refcount",
+		.read_u64 = current_css_set_refcount_read,
+		.flags = CFTYPE_ONLY_ON_ROOT,
+	},
+
+	{
+		.name = "current_css_set_cg_links",
+		.seq_show = current_css_set_cg_links_read,
+		.flags = CFTYPE_ONLY_ON_ROOT,
+	},
+
+	{
+		.name = "css_links",
+		.seq_show = cgroup_css_links_read,
+	},
+
+	{
+		.name = "csses",
+		.seq_show = cgroup_subsys_states_read,
+	},
+
+	{
+		.name = "masks",
+		.seq_show = cgroup_masks_read,
+	},
+
+	{ }	/* terminate */
+};
+
+struct cgroup_subsys debug_cgrp_subsys = {
+	.css_alloc	= debug_css_alloc,
+	.css_free	= debug_css_free,
+	.legacy_cftypes	= debug_legacy_files,
+};
+
+/*
+ * On v2, debug is an implicit controller enabled by "cgroup_debug" boot
+ * parameter.
+ */
+void __init enable_debug_cgroup(void)
+{
+	debug_cgrp_subsys.dfl_cftypes = debug_files;
+	debug_cgrp_subsys.implicit_on_dfl = true;
+	debug_cgrp_subsys.threaded = true;
+}
diff --git a/kernel/cgroup/freezer.c b/kernel/cgroup/freezer.c
new file mode 100644
index 000000000..617861a54
--- /dev/null
+++ b/kernel/cgroup/freezer.c
@@ -0,0 +1,323 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/cgroup.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/sched/signal.h>
+
+#include "cgroup-internal.h"
+
+#include <trace/events/cgroup.h>
+
+/*
+ * Propagate the cgroup frozen state upwards by the cgroup tree.
+ */
+static void cgroup_propagate_frozen(struct cgroup *cgrp, bool frozen)
+{
+	int desc = 1;
+
+	/*
+	 * If the new state is frozen, some freezing ancestor cgroups may change
+	 * their state too, depending on if all their descendants are frozen.
+	 *
+	 * Otherwise, all ancestor cgroups are forced into the non-frozen state.
+	 */
+	while ((cgrp = cgroup_parent(cgrp))) {
+		if (frozen) {
+			cgrp->freezer.nr_frozen_descendants += desc;
+			if (!test_bit(CGRP_FROZEN, &cgrp->flags) &&
+			    test_bit(CGRP_FREEZE, &cgrp->flags) &&
+			    cgrp->freezer.nr_frozen_descendants ==
+			    cgrp->nr_descendants) {
+				set_bit(CGRP_FROZEN, &cgrp->flags);
+				cgroup_file_notify(&cgrp->events_file);
+				TRACE_CGROUP_PATH(notify_frozen, cgrp, 1);
+				desc++;
+			}
+		} else {
+			cgrp->freezer.nr_frozen_descendants -= desc;
+			if (test_bit(CGRP_FROZEN, &cgrp->flags)) {
+				clear_bit(CGRP_FROZEN, &cgrp->flags);
+				cgroup_file_notify(&cgrp->events_file);
+				TRACE_CGROUP_PATH(notify_frozen, cgrp, 0);
+				desc++;
+			}
+		}
+	}
+}
+
+/*
+ * Revisit the cgroup frozen state.
+ * Checks if the cgroup is really frozen and perform all state transitions.
+ */
+void cgroup_update_frozen(struct cgroup *cgrp)
+{
+	bool frozen;
+
+	lockdep_assert_held(&css_set_lock);
+
+	/*
+	 * If the cgroup has to be frozen (CGRP_FREEZE bit set),
+	 * and all tasks are frozen and/or stopped, let's consider
+	 * the cgroup frozen. Otherwise it's not frozen.
+	 */
+	frozen = test_bit(CGRP_FREEZE, &cgrp->flags) &&
+		cgrp->freezer.nr_frozen_tasks == __cgroup_task_count(cgrp);
+
+	if (frozen) {
+		/* Already there? */
+		if (test_bit(CGRP_FROZEN, &cgrp->flags))
+			return;
+
+		set_bit(CGRP_FROZEN, &cgrp->flags);
+	} else {
+		/* Already there? */
+		if (!test_bit(CGRP_FROZEN, &cgrp->flags))
+			return;
+
+		clear_bit(CGRP_FROZEN, &cgrp->flags);
+	}
+	cgroup_file_notify(&cgrp->events_file);
+	TRACE_CGROUP_PATH(notify_frozen, cgrp, frozen);
+
+	/* Update the state of ancestor cgroups. */
+	cgroup_propagate_frozen(cgrp, frozen);
+}
+
+/*
+ * Increment cgroup's nr_frozen_tasks.
+ */
+static void cgroup_inc_frozen_cnt(struct cgroup *cgrp)
+{
+	cgrp->freezer.nr_frozen_tasks++;
+}
+
+/*
+ * Decrement cgroup's nr_frozen_tasks.
+ */
+static void cgroup_dec_frozen_cnt(struct cgroup *cgrp)
+{
+	cgrp->freezer.nr_frozen_tasks--;
+	WARN_ON_ONCE(cgrp->freezer.nr_frozen_tasks < 0);
+}
+
+/*
+ * Enter frozen/stopped state, if not yet there. Update cgroup's counters,
+ * and revisit the state of the cgroup, if necessary.
+ */
+void cgroup_enter_frozen(void)
+{
+	struct cgroup *cgrp;
+
+	if (current->frozen)
+		return;
+
+	spin_lock_irq(&css_set_lock);
+	current->frozen = true;
+	cgrp = task_dfl_cgroup(current);
+	cgroup_inc_frozen_cnt(cgrp);
+	cgroup_update_frozen(cgrp);
+	spin_unlock_irq(&css_set_lock);
+}
+
+/*
+ * Conditionally leave frozen/stopped state. Update cgroup's counters,
+ * and revisit the state of the cgroup, if necessary.
+ *
+ * If always_leave is not set, and the cgroup is freezing,
+ * we're racing with the cgroup freezing. In this case, we don't
+ * drop the frozen counter to avoid a transient switch to
+ * the unfrozen state.
+ */
+void cgroup_leave_frozen(bool always_leave)
+{
+	struct cgroup *cgrp;
+
+	spin_lock_irq(&css_set_lock);
+	cgrp = task_dfl_cgroup(current);
+	if (always_leave || !test_bit(CGRP_FREEZE, &cgrp->flags)) {
+		cgroup_dec_frozen_cnt(cgrp);
+		cgroup_update_frozen(cgrp);
+		WARN_ON_ONCE(!current->frozen);
+		current->frozen = false;
+	} else if (!(current->jobctl & JOBCTL_TRAP_FREEZE)) {
+		spin_lock(&current->sighand->siglock);
+		current->jobctl |= JOBCTL_TRAP_FREEZE;
+		set_thread_flag(TIF_SIGPENDING);
+		spin_unlock(&current->sighand->siglock);
+	}
+	spin_unlock_irq(&css_set_lock);
+}
+
+/*
+ * Freeze or unfreeze the task by setting or clearing the JOBCTL_TRAP_FREEZE
+ * jobctl bit.
+ */
+static void cgroup_freeze_task(struct task_struct *task, bool freeze)
+{
+	unsigned long flags;
+
+	/* If the task is about to die, don't bother with freezing it. */
+	if (!lock_task_sighand(task, &flags))
+		return;
+
+	if (freeze) {
+		task->jobctl |= JOBCTL_TRAP_FREEZE;
+		signal_wake_up(task, false);
+	} else {
+		task->jobctl &= ~JOBCTL_TRAP_FREEZE;
+		wake_up_process(task);
+	}
+
+	unlock_task_sighand(task, &flags);
+}
+
+/*
+ * Freeze or unfreeze all tasks in the given cgroup.
+ */
+static void cgroup_do_freeze(struct cgroup *cgrp, bool freeze)
+{
+	struct css_task_iter it;
+	struct task_struct *task;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	spin_lock_irq(&css_set_lock);
+	if (freeze)
+		set_bit(CGRP_FREEZE, &cgrp->flags);
+	else
+		clear_bit(CGRP_FREEZE, &cgrp->flags);
+	spin_unlock_irq(&css_set_lock);
+
+	if (freeze)
+		TRACE_CGROUP_PATH(freeze, cgrp);
+	else
+		TRACE_CGROUP_PATH(unfreeze, cgrp);
+
+	css_task_iter_start(&cgrp->self, 0, &it);
+	while ((task = css_task_iter_next(&it))) {
+		/*
+		 * Ignore kernel threads here. Freezing cgroups containing
+		 * kthreads isn't supported.
+		 */
+		if (task->flags & PF_KTHREAD)
+			continue;
+		cgroup_freeze_task(task, freeze);
+	}
+	css_task_iter_end(&it);
+
+	/*
+	 * Cgroup state should be revisited here to cover empty leaf cgroups
+	 * and cgroups which descendants are already in the desired state.
+	 */
+	spin_lock_irq(&css_set_lock);
+	if (cgrp->nr_descendants == cgrp->freezer.nr_frozen_descendants)
+		cgroup_update_frozen(cgrp);
+	spin_unlock_irq(&css_set_lock);
+}
+
+/*
+ * Adjust the task state (freeze or unfreeze) and revisit the state of
+ * source and destination cgroups.
+ */
+void cgroup_freezer_migrate_task(struct task_struct *task,
+				 struct cgroup *src, struct cgroup *dst)
+{
+	lockdep_assert_held(&css_set_lock);
+
+	/*
+	 * Kernel threads are not supposed to be frozen at all.
+	 */
+	if (task->flags & PF_KTHREAD)
+		return;
+
+	/*
+	 * It's not necessary to do changes if both of the src and dst cgroups
+	 * are not freezing and task is not frozen.
+	 */
+	if (!test_bit(CGRP_FREEZE, &src->flags) &&
+	    !test_bit(CGRP_FREEZE, &dst->flags) &&
+	    !task->frozen)
+		return;
+
+	/*
+	 * Adjust counters of freezing and frozen tasks.
+	 * Note, that if the task is frozen, but the destination cgroup is not
+	 * frozen, we bump both counters to keep them balanced.
+	 */
+	if (task->frozen) {
+		cgroup_inc_frozen_cnt(dst);
+		cgroup_dec_frozen_cnt(src);
+	}
+	cgroup_update_frozen(dst);
+	cgroup_update_frozen(src);
+
+	/*
+	 * Force the task to the desired state.
+	 */
+	cgroup_freeze_task(task, test_bit(CGRP_FREEZE, &dst->flags));
+}
+
+void cgroup_freeze(struct cgroup *cgrp, bool freeze)
+{
+	struct cgroup_subsys_state *css;
+	struct cgroup *dsct;
+	bool applied = false;
+
+	lockdep_assert_held(&cgroup_mutex);
+
+	/*
+	 * Nothing changed? Just exit.
+	 */
+	if (cgrp->freezer.freeze == freeze)
+		return;
+
+	cgrp->freezer.freeze = freeze;
+
+	/*
+	 * Propagate changes downwards the cgroup tree.
+	 */
+	css_for_each_descendant_pre(css, &cgrp->self) {
+		dsct = css->cgroup;
+
+		if (cgroup_is_dead(dsct))
+			continue;
+
+		if (freeze) {
+			dsct->freezer.e_freeze++;
+			/*
+			 * Already frozen because of ancestor's settings?
+			 */
+			if (dsct->freezer.e_freeze > 1)
+				continue;
+		} else {
+			dsct->freezer.e_freeze--;
+			/*
+			 * Still frozen because of ancestor's settings?
+			 */
+			if (dsct->freezer.e_freeze > 0)
+				continue;
+
+			WARN_ON_ONCE(dsct->freezer.e_freeze < 0);
+		}
+
+		/*
+		 * Do change actual state: freeze or unfreeze.
+		 */
+		cgroup_do_freeze(dsct, freeze);
+		applied = true;
+	}
+
+	/*
+	 * Even if the actual state hasn't changed, let's notify a user.
+	 * The state can be enforced by an ancestor cgroup: the cgroup
+	 * can already be in the desired state or it can be locked in the
+	 * opposite state, so that the transition will never happen.
+	 * In both cases it's better to notify a user, that there is
+	 * nothing to wait for.
+	 */
+	if (!applied) {
+		TRACE_CGROUP_PATH(notify_frozen, cgrp,
+				  test_bit(CGRP_FROZEN, &cgrp->flags));
+		cgroup_file_notify(&cgrp->events_file);
+	}
+}
diff --git a/kernel/cgroup/legacy_freezer.c b/kernel/cgroup/legacy_freezer.c
new file mode 100644
index 000000000..66d170804
--- /dev/null
+++ b/kernel/cgroup/legacy_freezer.c
@@ -0,0 +1,487 @@
+/*
+ * cgroup_freezer.c -  control group freezer subsystem
+ *
+ * Copyright IBM Corporation, 2007
+ *
+ * Author : Cedric Le Goater <clg@fr.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/cgroup.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <linux/freezer.h>
+#include <linux/seq_file.h>
+#include <linux/mutex.h>
+#include <linux/cpu.h>
+
+/*
+ * A cgroup is freezing if any FREEZING flags are set.  FREEZING_SELF is
+ * set if "FROZEN" is written to freezer.state cgroupfs file, and cleared
+ * for "THAWED".  FREEZING_PARENT is set if the parent freezer is FREEZING
+ * for whatever reason.  IOW, a cgroup has FREEZING_PARENT set if one of
+ * its ancestors has FREEZING_SELF set.
+ */
+enum freezer_state_flags {
+	CGROUP_FREEZER_ONLINE	= (1 << 0), /* freezer is fully online */
+	CGROUP_FREEZING_SELF	= (1 << 1), /* this freezer is freezing */
+	CGROUP_FREEZING_PARENT	= (1 << 2), /* the parent freezer is freezing */
+	CGROUP_FROZEN		= (1 << 3), /* this and its descendants frozen */
+
+	/* mask for all FREEZING flags */
+	CGROUP_FREEZING		= CGROUP_FREEZING_SELF | CGROUP_FREEZING_PARENT,
+};
+
+struct freezer {
+	struct cgroup_subsys_state	css;
+	unsigned int			state;
+};
+
+static DEFINE_MUTEX(freezer_mutex);
+
+static inline struct freezer *css_freezer(struct cgroup_subsys_state *css)
+{
+	return css ? container_of(css, struct freezer, css) : NULL;
+}
+
+static inline struct freezer *task_freezer(struct task_struct *task)
+{
+	return css_freezer(task_css(task, freezer_cgrp_id));
+}
+
+static struct freezer *parent_freezer(struct freezer *freezer)
+{
+	return css_freezer(freezer->css.parent);
+}
+
+bool cgroup_freezing(struct task_struct *task)
+{
+	bool ret;
+	unsigned int state;
+
+	rcu_read_lock();
+	/* Check if the cgroup is still FREEZING, but not FROZEN. The extra
+	 * !FROZEN check is required, because the FREEZING bit is not cleared
+	 * when the state FROZEN is reached.
+	 */
+	state = task_freezer(task)->state;
+	ret = (state & CGROUP_FREEZING) && !(state & CGROUP_FROZEN);
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static const char *freezer_state_strs(unsigned int state)
+{
+	if (state & CGROUP_FROZEN)
+		return "FROZEN";
+	if (state & CGROUP_FREEZING)
+		return "FREEZING";
+	return "THAWED";
+};
+
+static struct cgroup_subsys_state *
+freezer_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+	struct freezer *freezer;
+
+	freezer = kzalloc(sizeof(struct freezer), GFP_KERNEL);
+	if (!freezer)
+		return ERR_PTR(-ENOMEM);
+
+	return &freezer->css;
+}
+
+/**
+ * freezer_css_online - commit creation of a freezer css
+ * @css: css being created
+ *
+ * We're committing to creation of @css.  Mark it online and inherit
+ * parent's freezing state while holding both parent's and our
+ * freezer->lock.
+ */
+static int freezer_css_online(struct cgroup_subsys_state *css)
+{
+	struct freezer *freezer = css_freezer(css);
+	struct freezer *parent = parent_freezer(freezer);
+
+	cpus_read_lock();
+	mutex_lock(&freezer_mutex);
+
+	freezer->state |= CGROUP_FREEZER_ONLINE;
+
+	if (parent && (parent->state & CGROUP_FREEZING)) {
+		freezer->state |= CGROUP_FREEZING_PARENT | CGROUP_FROZEN;
+		static_branch_inc_cpuslocked(&freezer_active);
+	}
+
+	mutex_unlock(&freezer_mutex);
+	cpus_read_unlock();
+	return 0;
+}
+
+/**
+ * freezer_css_offline - initiate destruction of a freezer css
+ * @css: css being destroyed
+ *
+ * @css is going away.  Mark it dead and decrement system_freezing_count if
+ * it was holding one.
+ */
+static void freezer_css_offline(struct cgroup_subsys_state *css)
+{
+	struct freezer *freezer = css_freezer(css);
+
+	cpus_read_lock();
+	mutex_lock(&freezer_mutex);
+
+	if (freezer->state & CGROUP_FREEZING)
+		static_branch_dec_cpuslocked(&freezer_active);
+
+	freezer->state = 0;
+
+	mutex_unlock(&freezer_mutex);
+	cpus_read_unlock();
+}
+
+static void freezer_css_free(struct cgroup_subsys_state *css)
+{
+	kfree(css_freezer(css));
+}
+
+/*
+ * Tasks can be migrated into a different freezer anytime regardless of its
+ * current state.  freezer_attach() is responsible for making new tasks
+ * conform to the current state.
+ *
+ * Freezer state changes and task migration are synchronized via
+ * @freezer->lock.  freezer_attach() makes the new tasks conform to the
+ * current state and all following state changes can see the new tasks.
+ */
+static void freezer_attach(struct cgroup_taskset *tset)
+{
+	struct task_struct *task;
+	struct cgroup_subsys_state *new_css;
+
+	mutex_lock(&freezer_mutex);
+
+	/*
+	 * Make the new tasks conform to the current state of @new_css.
+	 * For simplicity, when migrating any task to a FROZEN cgroup, we
+	 * revert it to FREEZING and let update_if_frozen() determine the
+	 * correct state later.
+	 *
+	 * Tasks in @tset are on @new_css but may not conform to its
+	 * current state before executing the following - !frozen tasks may
+	 * be visible in a FROZEN cgroup and frozen tasks in a THAWED one.
+	 */
+	cgroup_taskset_for_each(task, new_css, tset) {
+		struct freezer *freezer = css_freezer(new_css);
+
+		if (!(freezer->state & CGROUP_FREEZING)) {
+			__thaw_task(task);
+		} else {
+			freeze_task(task);
+
+			/* clear FROZEN and propagate upwards */
+			while (freezer && (freezer->state & CGROUP_FROZEN)) {
+				freezer->state &= ~CGROUP_FROZEN;
+				freezer = parent_freezer(freezer);
+			}
+		}
+	}
+
+	mutex_unlock(&freezer_mutex);
+}
+
+/**
+ * freezer_fork - cgroup post fork callback
+ * @task: a task which has just been forked
+ *
+ * @task has just been created and should conform to the current state of
+ * the cgroup_freezer it belongs to.  This function may race against
+ * freezer_attach().  Losing to freezer_attach() means that we don't have
+ * to do anything as freezer_attach() will put @task into the appropriate
+ * state.
+ */
+static void freezer_fork(struct task_struct *task)
+{
+	struct freezer *freezer;
+
+	/*
+	 * The root cgroup is non-freezable, so we can skip locking the
+	 * freezer.  This is safe regardless of race with task migration.
+	 * If we didn't race or won, skipping is obviously the right thing
+	 * to do.  If we lost and root is the new cgroup, noop is still the
+	 * right thing to do.
+	 */
+	if (task_css_is_root(task, freezer_cgrp_id))
+		return;
+
+	mutex_lock(&freezer_mutex);
+	rcu_read_lock();
+
+	freezer = task_freezer(task);
+	if (freezer->state & CGROUP_FREEZING)
+		freeze_task(task);
+
+	rcu_read_unlock();
+	mutex_unlock(&freezer_mutex);
+}
+
+/**
+ * update_if_frozen - update whether a cgroup finished freezing
+ * @css: css of interest
+ *
+ * Once FREEZING is initiated, transition to FROZEN is lazily updated by
+ * calling this function.  If the current state is FREEZING but not FROZEN,
+ * this function checks whether all tasks of this cgroup and the descendant
+ * cgroups finished freezing and, if so, sets FROZEN.
+ *
+ * The caller is responsible for grabbing RCU read lock and calling
+ * update_if_frozen() on all descendants prior to invoking this function.
+ *
+ * Task states and freezer state might disagree while tasks are being
+ * migrated into or out of @css, so we can't verify task states against
+ * @freezer state here.  See freezer_attach() for details.
+ */
+static void update_if_frozen(struct cgroup_subsys_state *css)
+{
+	struct freezer *freezer = css_freezer(css);
+	struct cgroup_subsys_state *pos;
+	struct css_task_iter it;
+	struct task_struct *task;
+
+	lockdep_assert_held(&freezer_mutex);
+
+	if (!(freezer->state & CGROUP_FREEZING) ||
+	    (freezer->state & CGROUP_FROZEN))
+		return;
+
+	/* are all (live) children frozen? */
+	rcu_read_lock();
+	css_for_each_child(pos, css) {
+		struct freezer *child = css_freezer(pos);
+
+		if ((child->state & CGROUP_FREEZER_ONLINE) &&
+		    !(child->state & CGROUP_FROZEN)) {
+			rcu_read_unlock();
+			return;
+		}
+	}
+	rcu_read_unlock();
+
+	/* are all tasks frozen? */
+	css_task_iter_start(css, 0, &it);
+
+	while ((task = css_task_iter_next(&it))) {
+		if (freezing(task) && !frozen(task))
+			goto out_iter_end;
+	}
+
+	freezer->state |= CGROUP_FROZEN;
+out_iter_end:
+	css_task_iter_end(&it);
+}
+
+static int freezer_read(struct seq_file *m, void *v)
+{
+	struct cgroup_subsys_state *css = seq_css(m), *pos;
+
+	mutex_lock(&freezer_mutex);
+	rcu_read_lock();
+
+	/* update states bottom-up */
+	css_for_each_descendant_post(pos, css) {
+		if (!css_tryget_online(pos))
+			continue;
+		rcu_read_unlock();
+
+		update_if_frozen(pos);
+
+		rcu_read_lock();
+		css_put(pos);
+	}
+
+	rcu_read_unlock();
+	mutex_unlock(&freezer_mutex);
+
+	seq_puts(m, freezer_state_strs(css_freezer(css)->state));
+	seq_putc(m, '\n');
+	return 0;
+}
+
+static void freeze_cgroup(struct freezer *freezer)
+{
+	struct css_task_iter it;
+	struct task_struct *task;
+
+	css_task_iter_start(&freezer->css, 0, &it);
+	while ((task = css_task_iter_next(&it)))
+		freeze_task(task);
+	css_task_iter_end(&it);
+}
+
+static void unfreeze_cgroup(struct freezer *freezer)
+{
+	struct css_task_iter it;
+	struct task_struct *task;
+
+	css_task_iter_start(&freezer->css, 0, &it);
+	while ((task = css_task_iter_next(&it)))
+		__thaw_task(task);
+	css_task_iter_end(&it);
+}
+
+/**
+ * freezer_apply_state - apply state change to a single cgroup_freezer
+ * @freezer: freezer to apply state change to
+ * @freeze: whether to freeze or unfreeze
+ * @state: CGROUP_FREEZING_* flag to set or clear
+ *
+ * Set or clear @state on @cgroup according to @freeze, and perform
+ * freezing or thawing as necessary.
+ */
+static void freezer_apply_state(struct freezer *freezer, bool freeze,
+				unsigned int state)
+{
+	/* also synchronizes against task migration, see freezer_attach() */
+	lockdep_assert_held(&freezer_mutex);
+
+	if (!(freezer->state & CGROUP_FREEZER_ONLINE))
+		return;
+
+	if (freeze) {
+		if (!(freezer->state & CGROUP_FREEZING))
+			static_branch_inc_cpuslocked(&freezer_active);
+		freezer->state |= state;
+		freeze_cgroup(freezer);
+	} else {
+		bool was_freezing = freezer->state & CGROUP_FREEZING;
+
+		freezer->state &= ~state;
+
+		if (!(freezer->state & CGROUP_FREEZING)) {
+			freezer->state &= ~CGROUP_FROZEN;
+			if (was_freezing)
+				static_branch_dec_cpuslocked(&freezer_active);
+			unfreeze_cgroup(freezer);
+		}
+	}
+}
+
+/**
+ * freezer_change_state - change the freezing state of a cgroup_freezer
+ * @freezer: freezer of interest
+ * @freeze: whether to freeze or thaw
+ *
+ * Freeze or thaw @freezer according to @freeze.  The operations are
+ * recursive - all descendants of @freezer will be affected.
+ */
+static void freezer_change_state(struct freezer *freezer, bool freeze)
+{
+	struct cgroup_subsys_state *pos;
+
+	cpus_read_lock();
+	/*
+	 * Update all its descendants in pre-order traversal.  Each
+	 * descendant will try to inherit its parent's FREEZING state as
+	 * CGROUP_FREEZING_PARENT.
+	 */
+	mutex_lock(&freezer_mutex);
+	rcu_read_lock();
+	css_for_each_descendant_pre(pos, &freezer->css) {
+		struct freezer *pos_f = css_freezer(pos);
+		struct freezer *parent = parent_freezer(pos_f);
+
+		if (!css_tryget_online(pos))
+			continue;
+		rcu_read_unlock();
+
+		if (pos_f == freezer)
+			freezer_apply_state(pos_f, freeze,
+					    CGROUP_FREEZING_SELF);
+		else
+			freezer_apply_state(pos_f,
+					    parent->state & CGROUP_FREEZING,
+					    CGROUP_FREEZING_PARENT);
+
+		rcu_read_lock();
+		css_put(pos);
+	}
+	rcu_read_unlock();
+	mutex_unlock(&freezer_mutex);
+	cpus_read_unlock();
+}
+
+static ssize_t freezer_write(struct kernfs_open_file *of,
+			     char *buf, size_t nbytes, loff_t off)
+{
+	bool freeze;
+
+	buf = strstrip(buf);
+
+	if (strcmp(buf, freezer_state_strs(0)) == 0)
+		freeze = false;
+	else if (strcmp(buf, freezer_state_strs(CGROUP_FROZEN)) == 0)
+		freeze = true;
+	else
+		return -EINVAL;
+
+	freezer_change_state(css_freezer(of_css(of)), freeze);
+	return nbytes;
+}
+
+static u64 freezer_self_freezing_read(struct cgroup_subsys_state *css,
+				      struct cftype *cft)
+{
+	struct freezer *freezer = css_freezer(css);
+
+	return (bool)(freezer->state & CGROUP_FREEZING_SELF);
+}
+
+static u64 freezer_parent_freezing_read(struct cgroup_subsys_state *css,
+					struct cftype *cft)
+{
+	struct freezer *freezer = css_freezer(css);
+
+	return (bool)(freezer->state & CGROUP_FREEZING_PARENT);
+}
+
+static struct cftype files[] = {
+	{
+		.name = "state",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = freezer_read,
+		.write = freezer_write,
+	},
+	{
+		.name = "self_freezing",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_u64 = freezer_self_freezing_read,
+	},
+	{
+		.name = "parent_freezing",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_u64 = freezer_parent_freezing_read,
+	},
+	{ }	/* terminate */
+};
+
+struct cgroup_subsys freezer_cgrp_subsys = {
+	.css_alloc	= freezer_css_alloc,
+	.css_online	= freezer_css_online,
+	.css_offline	= freezer_css_offline,
+	.css_free	= freezer_css_free,
+	.attach		= freezer_attach,
+	.fork		= freezer_fork,
+	.legacy_cftypes	= files,
+};
diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
new file mode 100644
index 000000000..fe3e8a0eb
--- /dev/null
+++ b/kernel/cgroup/misc.c
@@ -0,0 +1,424 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Miscellaneous cgroup controller
+ *
+ * Copyright 2020 Google LLC
+ * Author: Vipin Sharma <vipinsh@google.com>
+ */
+
+#include <linux/limits.h>
+#include <linux/cgroup.h>
+#include <linux/errno.h>
+#include <linux/atomic.h>
+#include <linux/slab.h>
+#include <linux/misc_cgroup.h>
+
+#define MAX_STR "max"
+#define MAX_NUM ULONG_MAX
+
+/* Miscellaneous res name, keep it in sync with enum misc_res_type */
+static const char *const misc_res_name[] = {
+#ifdef CONFIG_KVM_AMD_SEV
+	/* AMD SEV ASIDs resource */
+	"sev",
+	/* AMD SEV-ES ASIDs resource */
+	"sev_es",
+#endif
+};
+
+/* Root misc cgroup */
+static struct misc_cg root_cg;
+
+/*
+ * Miscellaneous resources capacity for the entire machine. 0 capacity means
+ * resource is not initialized or not present in the host.
+ *
+ * root_cg.max and capacity are independent of each other. root_cg.max can be
+ * more than the actual capacity. We are using Limits resource distribution
+ * model of cgroup for miscellaneous controller.
+ */
+static unsigned long misc_res_capacity[MISC_CG_RES_TYPES];
+
+/**
+ * parent_misc() - Get the parent of the passed misc cgroup.
+ * @cgroup: cgroup whose parent needs to be fetched.
+ *
+ * Context: Any context.
+ * Return:
+ * * struct misc_cg* - Parent of the @cgroup.
+ * * %NULL - If @cgroup is null or the passed cgroup does not have a parent.
+ */
+static struct misc_cg *parent_misc(struct misc_cg *cgroup)
+{
+	return cgroup ? css_misc(cgroup->css.parent) : NULL;
+}
+
+/**
+ * valid_type() - Check if @type is valid or not.
+ * @type: misc res type.
+ *
+ * Context: Any context.
+ * Return:
+ * * true - If valid type.
+ * * false - If not valid type.
+ */
+static inline bool valid_type(enum misc_res_type type)
+{
+	return type >= 0 && type < MISC_CG_RES_TYPES;
+}
+
+/**
+ * misc_cg_res_total_usage() - Get the current total usage of the resource.
+ * @type: misc res type.
+ *
+ * Context: Any context.
+ * Return: Current total usage of the resource.
+ */
+unsigned long misc_cg_res_total_usage(enum misc_res_type type)
+{
+	if (valid_type(type))
+		return atomic_long_read(&root_cg.res[type].usage);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(misc_cg_res_total_usage);
+
+/**
+ * misc_cg_set_capacity() - Set the capacity of the misc cgroup res.
+ * @type: Type of the misc res.
+ * @capacity: Supported capacity of the misc res on the host.
+ *
+ * If capacity is 0 then the charging a misc cgroup fails for that type.
+ *
+ * Context: Any context.
+ * Return:
+ * * %0 - Successfully registered the capacity.
+ * * %-EINVAL - If @type is invalid.
+ */
+int misc_cg_set_capacity(enum misc_res_type type, unsigned long capacity)
+{
+	if (!valid_type(type))
+		return -EINVAL;
+
+	WRITE_ONCE(misc_res_capacity[type], capacity);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(misc_cg_set_capacity);
+
+/**
+ * misc_cg_cancel_charge() - Cancel the charge from the misc cgroup.
+ * @type: Misc res type in misc cg to cancel the charge from.
+ * @cg: Misc cgroup to cancel charge from.
+ * @amount: Amount to cancel.
+ *
+ * Context: Any context.
+ */
+static void misc_cg_cancel_charge(enum misc_res_type type, struct misc_cg *cg,
+				  unsigned long amount)
+{
+	WARN_ONCE(atomic_long_add_negative(-amount, &cg->res[type].usage),
+		  "misc cgroup resource %s became less than 0",
+		  misc_res_name[type]);
+}
+
+/**
+ * misc_cg_try_charge() - Try charging the misc cgroup.
+ * @type: Misc res type to charge.
+ * @cg: Misc cgroup which will be charged.
+ * @amount: Amount to charge.
+ *
+ * Charge @amount to the misc cgroup. Caller must use the same cgroup during
+ * the uncharge call.
+ *
+ * Context: Any context.
+ * Return:
+ * * %0 - If successfully charged.
+ * * -EINVAL - If @type is invalid or misc res has 0 capacity.
+ * * -EBUSY - If max limit will be crossed or total usage will be more than the
+ *	      capacity.
+ */
+int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
+		       unsigned long amount)
+{
+	struct misc_cg *i, *j;
+	int ret;
+	struct misc_res *res;
+	int new_usage;
+
+	if (!(valid_type(type) && cg && READ_ONCE(misc_res_capacity[type])))
+		return -EINVAL;
+
+	if (!amount)
+		return 0;
+
+	for (i = cg; i; i = parent_misc(i)) {
+		res = &i->res[type];
+
+		new_usage = atomic_long_add_return(amount, &res->usage);
+		if (new_usage > READ_ONCE(res->max) ||
+		    new_usage > READ_ONCE(misc_res_capacity[type])) {
+			ret = -EBUSY;
+			goto err_charge;
+		}
+	}
+	return 0;
+
+err_charge:
+	for (j = i; j; j = parent_misc(j)) {
+		atomic_long_inc(&j->res[type].events);
+		cgroup_file_notify(&j->events_file);
+	}
+
+	for (j = cg; j != i; j = parent_misc(j))
+		misc_cg_cancel_charge(type, j, amount);
+	misc_cg_cancel_charge(type, i, amount);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(misc_cg_try_charge);
+
+/**
+ * misc_cg_uncharge() - Uncharge the misc cgroup.
+ * @type: Misc res type which was charged.
+ * @cg: Misc cgroup which will be uncharged.
+ * @amount: Charged amount.
+ *
+ * Context: Any context.
+ */
+void misc_cg_uncharge(enum misc_res_type type, struct misc_cg *cg,
+		      unsigned long amount)
+{
+	struct misc_cg *i;
+
+	if (!(amount && valid_type(type) && cg))
+		return;
+
+	for (i = cg; i; i = parent_misc(i))
+		misc_cg_cancel_charge(type, i, amount);
+}
+EXPORT_SYMBOL_GPL(misc_cg_uncharge);
+
+/**
+ * misc_cg_max_show() - Show the misc cgroup max limit.
+ * @sf: Interface file
+ * @v: Arguments passed
+ *
+ * Context: Any context.
+ * Return: 0 to denote successful print.
+ */
+static int misc_cg_max_show(struct seq_file *sf, void *v)
+{
+	int i;
+	struct misc_cg *cg = css_misc(seq_css(sf));
+	unsigned long max;
+
+	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
+		if (READ_ONCE(misc_res_capacity[i])) {
+			max = READ_ONCE(cg->res[i].max);
+			if (max == MAX_NUM)
+				seq_printf(sf, "%s max\n", misc_res_name[i]);
+			else
+				seq_printf(sf, "%s %lu\n", misc_res_name[i],
+					   max);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * misc_cg_max_write() - Update the maximum limit of the cgroup.
+ * @of: Handler for the file.
+ * @buf: Data from the user. It should be either "max", 0, or a positive
+ *	 integer.
+ * @nbytes: Number of bytes of the data.
+ * @off: Offset in the file.
+ *
+ * User can pass data like:
+ * echo sev 23 > misc.max, OR
+ * echo sev max > misc.max
+ *
+ * Context: Any context.
+ * Return:
+ * * >= 0 - Number of bytes processed in the input.
+ * * -EINVAL - If buf is not valid.
+ * * -ERANGE - If number is bigger than the unsigned long capacity.
+ */
+static ssize_t misc_cg_max_write(struct kernfs_open_file *of, char *buf,
+				 size_t nbytes, loff_t off)
+{
+	struct misc_cg *cg;
+	unsigned long max;
+	int ret = 0, i;
+	enum misc_res_type type = MISC_CG_RES_TYPES;
+	char *token;
+
+	buf = strstrip(buf);
+	token = strsep(&buf, " ");
+
+	if (!token || !buf)
+		return -EINVAL;
+
+	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
+		if (!strcmp(misc_res_name[i], token)) {
+			type = i;
+			break;
+		}
+	}
+
+	if (type == MISC_CG_RES_TYPES)
+		return -EINVAL;
+
+	if (!strcmp(MAX_STR, buf)) {
+		max = MAX_NUM;
+	} else {
+		ret = kstrtoul(buf, 0, &max);
+		if (ret)
+			return ret;
+	}
+
+	cg = css_misc(of_css(of));
+
+	if (READ_ONCE(misc_res_capacity[type]))
+		WRITE_ONCE(cg->res[type].max, max);
+	else
+		ret = -EINVAL;
+
+	return ret ? ret : nbytes;
+}
+
+/**
+ * misc_cg_current_show() - Show the current usage of the misc cgroup.
+ * @sf: Interface file
+ * @v: Arguments passed
+ *
+ * Context: Any context.
+ * Return: 0 to denote successful print.
+ */
+static int misc_cg_current_show(struct seq_file *sf, void *v)
+{
+	int i;
+	unsigned long usage;
+	struct misc_cg *cg = css_misc(seq_css(sf));
+
+	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
+		usage = atomic_long_read(&cg->res[i].usage);
+		if (READ_ONCE(misc_res_capacity[i]) || usage)
+			seq_printf(sf, "%s %lu\n", misc_res_name[i], usage);
+	}
+
+	return 0;
+}
+
+/**
+ * misc_cg_capacity_show() - Show the total capacity of misc res on the host.
+ * @sf: Interface file
+ * @v: Arguments passed
+ *
+ * Only present in the root cgroup directory.
+ *
+ * Context: Any context.
+ * Return: 0 to denote successful print.
+ */
+static int misc_cg_capacity_show(struct seq_file *sf, void *v)
+{
+	int i;
+	unsigned long cap;
+
+	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
+		cap = READ_ONCE(misc_res_capacity[i]);
+		if (cap)
+			seq_printf(sf, "%s %lu\n", misc_res_name[i], cap);
+	}
+
+	return 0;
+}
+
+static int misc_events_show(struct seq_file *sf, void *v)
+{
+	struct misc_cg *cg = css_misc(seq_css(sf));
+	unsigned long events, i;
+
+	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
+		events = atomic_long_read(&cg->res[i].events);
+		if (READ_ONCE(misc_res_capacity[i]) || events)
+			seq_printf(sf, "%s.max %lu\n", misc_res_name[i], events);
+	}
+	return 0;
+}
+
+/* Misc cgroup interface files */
+static struct cftype misc_cg_files[] = {
+	{
+		.name = "max",
+		.write = misc_cg_max_write,
+		.seq_show = misc_cg_max_show,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{
+		.name = "current",
+		.seq_show = misc_cg_current_show,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{
+		.name = "capacity",
+		.seq_show = misc_cg_capacity_show,
+		.flags = CFTYPE_ONLY_ON_ROOT,
+	},
+	{
+		.name = "events",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.file_offset = offsetof(struct misc_cg, events_file),
+		.seq_show = misc_events_show,
+	},
+	{}
+};
+
+/**
+ * misc_cg_alloc() - Allocate misc cgroup.
+ * @parent_css: Parent cgroup.
+ *
+ * Context: Process context.
+ * Return:
+ * * struct cgroup_subsys_state* - css of the allocated cgroup.
+ * * ERR_PTR(-ENOMEM) - No memory available to allocate.
+ */
+static struct cgroup_subsys_state *
+misc_cg_alloc(struct cgroup_subsys_state *parent_css)
+{
+	enum misc_res_type i;
+	struct misc_cg *cg;
+
+	if (!parent_css) {
+		cg = &root_cg;
+	} else {
+		cg = kzalloc(sizeof(*cg), GFP_KERNEL);
+		if (!cg)
+			return ERR_PTR(-ENOMEM);
+	}
+
+	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
+		WRITE_ONCE(cg->res[i].max, MAX_NUM);
+		atomic_long_set(&cg->res[i].usage, 0);
+	}
+
+	return &cg->css;
+}
+
+/**
+ * misc_cg_free() - Free the misc cgroup.
+ * @css: cgroup subsys object.
+ *
+ * Context: Any context.
+ */
+static void misc_cg_free(struct cgroup_subsys_state *css)
+{
+	kfree(css_misc(css));
+}
+
+/* Cgroup controller callbacks */
+struct cgroup_subsys misc_cgrp_subsys = {
+	.css_alloc = misc_cg_alloc,
+	.css_free = misc_cg_free,
+	.legacy_cftypes = misc_cg_files,
+	.dfl_cftypes = misc_cg_files,
+};
diff --git a/kernel/cgroup/namespace.c b/kernel/cgroup/namespace.c
new file mode 100644
index 000000000..144a464e4
--- /dev/null
+++ b/kernel/cgroup/namespace.c
@@ -0,0 +1,151 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "cgroup-internal.h"
+
+#include <linux/sched/task.h>
+#include <linux/slab.h>
+#include <linux/nsproxy.h>
+#include <linux/proc_ns.h>
+
+
+/* cgroup namespaces */
+
+static struct ucounts *inc_cgroup_namespaces(struct user_namespace *ns)
+{
+	return inc_ucount(ns, current_euid(), UCOUNT_CGROUP_NAMESPACES);
+}
+
+static void dec_cgroup_namespaces(struct ucounts *ucounts)
+{
+	dec_ucount(ucounts, UCOUNT_CGROUP_NAMESPACES);
+}
+
+static struct cgroup_namespace *alloc_cgroup_ns(void)
+{
+	struct cgroup_namespace *new_ns;
+	int ret;
+
+	new_ns = kzalloc(sizeof(struct cgroup_namespace), GFP_KERNEL_ACCOUNT);
+	if (!new_ns)
+		return ERR_PTR(-ENOMEM);
+	ret = ns_alloc_inum(&new_ns->ns);
+	if (ret) {
+		kfree(new_ns);
+		return ERR_PTR(ret);
+	}
+	refcount_set(&new_ns->ns.count, 1);
+	new_ns->ns.ops = &cgroupns_operations;
+	return new_ns;
+}
+
+void free_cgroup_ns(struct cgroup_namespace *ns)
+{
+	put_css_set(ns->root_cset);
+	dec_cgroup_namespaces(ns->ucounts);
+	put_user_ns(ns->user_ns);
+	ns_free_inum(&ns->ns);
+	kfree(ns);
+}
+EXPORT_SYMBOL(free_cgroup_ns);
+
+struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
+					struct user_namespace *user_ns,
+					struct cgroup_namespace *old_ns)
+{
+	struct cgroup_namespace *new_ns;
+	struct ucounts *ucounts;
+	struct css_set *cset;
+
+	BUG_ON(!old_ns);
+
+	if (!(flags & CLONE_NEWCGROUP)) {
+		get_cgroup_ns(old_ns);
+		return old_ns;
+	}
+
+	/* Allow only sysadmin to create cgroup namespace. */
+	if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+		return ERR_PTR(-EPERM);
+
+	ucounts = inc_cgroup_namespaces(user_ns);
+	if (!ucounts)
+		return ERR_PTR(-ENOSPC);
+
+	/* It is not safe to take cgroup_mutex here */
+	spin_lock_irq(&css_set_lock);
+	cset = task_css_set(current);
+	get_css_set(cset);
+	spin_unlock_irq(&css_set_lock);
+
+	new_ns = alloc_cgroup_ns();
+	if (IS_ERR(new_ns)) {
+		put_css_set(cset);
+		dec_cgroup_namespaces(ucounts);
+		return new_ns;
+	}
+
+	new_ns->user_ns = get_user_ns(user_ns);
+	new_ns->ucounts = ucounts;
+	new_ns->root_cset = cset;
+
+	return new_ns;
+}
+
+static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct cgroup_namespace, ns);
+}
+
+static int cgroupns_install(struct nsset *nsset, struct ns_common *ns)
+{
+	struct nsproxy *nsproxy = nsset->nsproxy;
+	struct cgroup_namespace *cgroup_ns = to_cg_ns(ns);
+
+	if (!ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN) ||
+	    !ns_capable(cgroup_ns->user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	/* Don't need to do anything if we are attaching to our own cgroupns. */
+	if (cgroup_ns == nsproxy->cgroup_ns)
+		return 0;
+
+	get_cgroup_ns(cgroup_ns);
+	put_cgroup_ns(nsproxy->cgroup_ns);
+	nsproxy->cgroup_ns = cgroup_ns;
+
+	return 0;
+}
+
+static struct ns_common *cgroupns_get(struct task_struct *task)
+{
+	struct cgroup_namespace *ns = NULL;
+	struct nsproxy *nsproxy;
+
+	task_lock(task);
+	nsproxy = task->nsproxy;
+	if (nsproxy) {
+		ns = nsproxy->cgroup_ns;
+		get_cgroup_ns(ns);
+	}
+	task_unlock(task);
+
+	return ns ? &ns->ns : NULL;
+}
+
+static void cgroupns_put(struct ns_common *ns)
+{
+	put_cgroup_ns(to_cg_ns(ns));
+}
+
+static struct user_namespace *cgroupns_owner(struct ns_common *ns)
+{
+	return to_cg_ns(ns)->user_ns;
+}
+
+const struct proc_ns_operations cgroupns_operations = {
+	.name		= "cgroup",
+	.type		= CLONE_NEWCGROUP,
+	.get		= cgroupns_get,
+	.put		= cgroupns_put,
+	.install	= cgroupns_install,
+	.owner		= cgroupns_owner,
+};
diff --git a/kernel/cgroup/pids.c b/kernel/cgroup/pids.c
new file mode 100644
index 000000000..7695e60bc
--- /dev/null
+++ b/kernel/cgroup/pids.c
@@ -0,0 +1,387 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Process number limiting controller for cgroups.
+ *
+ * Used to allow a cgroup hierarchy to stop any new processes from fork()ing
+ * after a certain limit is reached.
+ *
+ * Since it is trivial to hit the task limit without hitting any kmemcg limits
+ * in place, PIDs are a fundamental resource. As such, PID exhaustion must be
+ * preventable in the scope of a cgroup hierarchy by allowing resource limiting
+ * of the number of tasks in a cgroup.
+ *
+ * In order to use the `pids` controller, set the maximum number of tasks in
+ * pids.max (this is not available in the root cgroup for obvious reasons). The
+ * number of processes currently in the cgroup is given by pids.current.
+ * Organisational operations are not blocked by cgroup policies, so it is
+ * possible to have pids.current > pids.max. However, it is not possible to
+ * violate a cgroup policy through fork(). fork() will return -EAGAIN if forking
+ * would cause a cgroup policy to be violated.
+ *
+ * To set a cgroup to have no limit, set pids.max to "max". This is the default
+ * for all new cgroups (N.B. that PID limits are hierarchical, so the most
+ * stringent limit in the hierarchy is followed).
+ *
+ * pids.current tracks all child cgroup hierarchies, so parent/pids.current is
+ * a superset of parent/child/pids.current.
+ *
+ * Copyright (C) 2015 Aleksa Sarai <cyphar@cyphar.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/threads.h>
+#include <linux/atomic.h>
+#include <linux/cgroup.h>
+#include <linux/slab.h>
+#include <linux/sched/task.h>
+
+#define PIDS_MAX (PID_MAX_LIMIT + 1ULL)
+#define PIDS_MAX_STR "max"
+
+struct pids_cgroup {
+	struct cgroup_subsys_state	css;
+
+	/*
+	 * Use 64-bit types so that we can safely represent "max" as
+	 * %PIDS_MAX = (%PID_MAX_LIMIT + 1).
+	 */
+	atomic64_t			counter;
+	atomic64_t			limit;
+	int64_t				watermark;
+
+	/* Handle for "pids.events" */
+	struct cgroup_file		events_file;
+
+	/* Number of times fork failed because limit was hit. */
+	atomic64_t			events_limit;
+};
+
+static struct pids_cgroup *css_pids(struct cgroup_subsys_state *css)
+{
+	return container_of(css, struct pids_cgroup, css);
+}
+
+static struct pids_cgroup *parent_pids(struct pids_cgroup *pids)
+{
+	return css_pids(pids->css.parent);
+}
+
+static struct cgroup_subsys_state *
+pids_css_alloc(struct cgroup_subsys_state *parent)
+{
+	struct pids_cgroup *pids;
+
+	pids = kzalloc(sizeof(struct pids_cgroup), GFP_KERNEL);
+	if (!pids)
+		return ERR_PTR(-ENOMEM);
+
+	atomic64_set(&pids->counter, 0);
+	atomic64_set(&pids->limit, PIDS_MAX);
+	atomic64_set(&pids->events_limit, 0);
+	return &pids->css;
+}
+
+static void pids_css_free(struct cgroup_subsys_state *css)
+{
+	kfree(css_pids(css));
+}
+
+static void pids_update_watermark(struct pids_cgroup *p, int64_t nr_pids)
+{
+	/*
+	 * This is racy, but we don't need perfectly accurate tallying of
+	 * the watermark, and this lets us avoid extra atomic overhead.
+	 */
+	if (nr_pids > READ_ONCE(p->watermark))
+		WRITE_ONCE(p->watermark, nr_pids);
+}
+
+/**
+ * pids_cancel - uncharge the local pid count
+ * @pids: the pid cgroup state
+ * @num: the number of pids to cancel
+ *
+ * This function will WARN if the pid count goes under 0, because such a case is
+ * a bug in the pids controller proper.
+ */
+static void pids_cancel(struct pids_cgroup *pids, int num)
+{
+	/*
+	 * A negative count (or overflow for that matter) is invalid,
+	 * and indicates a bug in the `pids` controller proper.
+	 */
+	WARN_ON_ONCE(atomic64_add_negative(-num, &pids->counter));
+}
+
+/**
+ * pids_uncharge - hierarchically uncharge the pid count
+ * @pids: the pid cgroup state
+ * @num: the number of pids to uncharge
+ */
+static void pids_uncharge(struct pids_cgroup *pids, int num)
+{
+	struct pids_cgroup *p;
+
+	for (p = pids; parent_pids(p); p = parent_pids(p))
+		pids_cancel(p, num);
+}
+
+/**
+ * pids_charge - hierarchically charge the pid count
+ * @pids: the pid cgroup state
+ * @num: the number of pids to charge
+ *
+ * This function does *not* follow the pid limit set. It cannot fail and the new
+ * pid count may exceed the limit. This is only used for reverting failed
+ * attaches, where there is no other way out than violating the limit.
+ */
+static void pids_charge(struct pids_cgroup *pids, int num)
+{
+	struct pids_cgroup *p;
+
+	for (p = pids; parent_pids(p); p = parent_pids(p)) {
+		int64_t new = atomic64_add_return(num, &p->counter);
+
+		pids_update_watermark(p, new);
+	}
+}
+
+/**
+ * pids_try_charge - hierarchically try to charge the pid count
+ * @pids: the pid cgroup state
+ * @num: the number of pids to charge
+ *
+ * This function follows the set limit. It will fail if the charge would cause
+ * the new value to exceed the hierarchical limit. Returns 0 if the charge
+ * succeeded, otherwise -EAGAIN.
+ */
+static int pids_try_charge(struct pids_cgroup *pids, int num)
+{
+	struct pids_cgroup *p, *q;
+
+	for (p = pids; parent_pids(p); p = parent_pids(p)) {
+		int64_t new = atomic64_add_return(num, &p->counter);
+		int64_t limit = atomic64_read(&p->limit);
+
+		/*
+		 * Since new is capped to the maximum number of pid_t, if
+		 * p->limit is %PIDS_MAX then we know that this test will never
+		 * fail.
+		 */
+		if (new > limit)
+			goto revert;
+
+		/*
+		 * Not technically accurate if we go over limit somewhere up
+		 * the hierarchy, but that's tolerable for the watermark.
+		 */
+		pids_update_watermark(p, new);
+	}
+
+	return 0;
+
+revert:
+	for (q = pids; q != p; q = parent_pids(q))
+		pids_cancel(q, num);
+	pids_cancel(p, num);
+
+	return -EAGAIN;
+}
+
+static int pids_can_attach(struct cgroup_taskset *tset)
+{
+	struct task_struct *task;
+	struct cgroup_subsys_state *dst_css;
+
+	cgroup_taskset_for_each(task, dst_css, tset) {
+		struct pids_cgroup *pids = css_pids(dst_css);
+		struct cgroup_subsys_state *old_css;
+		struct pids_cgroup *old_pids;
+
+		/*
+		 * No need to pin @old_css between here and cancel_attach()
+		 * because cgroup core protects it from being freed before
+		 * the migration completes or fails.
+		 */
+		old_css = task_css(task, pids_cgrp_id);
+		old_pids = css_pids(old_css);
+
+		pids_charge(pids, 1);
+		pids_uncharge(old_pids, 1);
+	}
+
+	return 0;
+}
+
+static void pids_cancel_attach(struct cgroup_taskset *tset)
+{
+	struct task_struct *task;
+	struct cgroup_subsys_state *dst_css;
+
+	cgroup_taskset_for_each(task, dst_css, tset) {
+		struct pids_cgroup *pids = css_pids(dst_css);
+		struct cgroup_subsys_state *old_css;
+		struct pids_cgroup *old_pids;
+
+		old_css = task_css(task, pids_cgrp_id);
+		old_pids = css_pids(old_css);
+
+		pids_charge(old_pids, 1);
+		pids_uncharge(pids, 1);
+	}
+}
+
+/*
+ * task_css_check(true) in pids_can_fork() and pids_cancel_fork() relies
+ * on cgroup_threadgroup_change_begin() held by the copy_process().
+ */
+static int pids_can_fork(struct task_struct *task, struct css_set *cset)
+{
+	struct cgroup_subsys_state *css;
+	struct pids_cgroup *pids;
+	int err;
+
+	if (cset)
+		css = cset->subsys[pids_cgrp_id];
+	else
+		css = task_css_check(current, pids_cgrp_id, true);
+	pids = css_pids(css);
+	err = pids_try_charge(pids, 1);
+	if (err) {
+		/* Only log the first time events_limit is incremented. */
+		if (atomic64_inc_return(&pids->events_limit) == 1) {
+			pr_info("cgroup: fork rejected by pids controller in ");
+			pr_cont_cgroup_path(css->cgroup);
+			pr_cont("\n");
+		}
+		cgroup_file_notify(&pids->events_file);
+	}
+	return err;
+}
+
+static void pids_cancel_fork(struct task_struct *task, struct css_set *cset)
+{
+	struct cgroup_subsys_state *css;
+	struct pids_cgroup *pids;
+
+	if (cset)
+		css = cset->subsys[pids_cgrp_id];
+	else
+		css = task_css_check(current, pids_cgrp_id, true);
+	pids = css_pids(css);
+	pids_uncharge(pids, 1);
+}
+
+static void pids_release(struct task_struct *task)
+{
+	struct pids_cgroup *pids = css_pids(task_css(task, pids_cgrp_id));
+
+	pids_uncharge(pids, 1);
+}
+
+static ssize_t pids_max_write(struct kernfs_open_file *of, char *buf,
+			      size_t nbytes, loff_t off)
+{
+	struct cgroup_subsys_state *css = of_css(of);
+	struct pids_cgroup *pids = css_pids(css);
+	int64_t limit;
+	int err;
+
+	buf = strstrip(buf);
+	if (!strcmp(buf, PIDS_MAX_STR)) {
+		limit = PIDS_MAX;
+		goto set_limit;
+	}
+
+	err = kstrtoll(buf, 0, &limit);
+	if (err)
+		return err;
+
+	if (limit < 0 || limit >= PIDS_MAX)
+		return -EINVAL;
+
+set_limit:
+	/*
+	 * Limit updates don't need to be mutex'd, since it isn't
+	 * critical that any racing fork()s follow the new limit.
+	 */
+	atomic64_set(&pids->limit, limit);
+	return nbytes;
+}
+
+static int pids_max_show(struct seq_file *sf, void *v)
+{
+	struct cgroup_subsys_state *css = seq_css(sf);
+	struct pids_cgroup *pids = css_pids(css);
+	int64_t limit = atomic64_read(&pids->limit);
+
+	if (limit >= PIDS_MAX)
+		seq_printf(sf, "%s\n", PIDS_MAX_STR);
+	else
+		seq_printf(sf, "%lld\n", limit);
+
+	return 0;
+}
+
+static s64 pids_current_read(struct cgroup_subsys_state *css,
+			     struct cftype *cft)
+{
+	struct pids_cgroup *pids = css_pids(css);
+
+	return atomic64_read(&pids->counter);
+}
+
+static s64 pids_peak_read(struct cgroup_subsys_state *css,
+			  struct cftype *cft)
+{
+	struct pids_cgroup *pids = css_pids(css);
+
+	return READ_ONCE(pids->watermark);
+}
+
+static int pids_events_show(struct seq_file *sf, void *v)
+{
+	struct pids_cgroup *pids = css_pids(seq_css(sf));
+
+	seq_printf(sf, "max %lld\n", (s64)atomic64_read(&pids->events_limit));
+	return 0;
+}
+
+static struct cftype pids_files[] = {
+	{
+		.name = "max",
+		.write = pids_max_write,
+		.seq_show = pids_max_show,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{
+		.name = "current",
+		.read_s64 = pids_current_read,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{
+		.name = "peak",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_s64 = pids_peak_read,
+	},
+	{
+		.name = "events",
+		.seq_show = pids_events_show,
+		.file_offset = offsetof(struct pids_cgroup, events_file),
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{ }	/* terminate */
+};
+
+struct cgroup_subsys pids_cgrp_subsys = {
+	.css_alloc	= pids_css_alloc,
+	.css_free	= pids_css_free,
+	.can_attach 	= pids_can_attach,
+	.cancel_attach 	= pids_cancel_attach,
+	.can_fork	= pids_can_fork,
+	.cancel_fork	= pids_cancel_fork,
+	.release	= pids_release,
+	.legacy_cftypes	= pids_files,
+	.dfl_cftypes	= pids_files,
+	.threaded	= true,
+};
diff --git a/kernel/cgroup/rdma.c b/kernel/cgroup/rdma.c
new file mode 100644
index 000000000..313540660
--- /dev/null
+++ b/kernel/cgroup/rdma.c
@@ -0,0 +1,610 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * RDMA resource limiting controller for cgroups.
+ *
+ * Used to allow a cgroup hierarchy to stop processes from consuming
+ * additional RDMA resources after a certain limit is reached.
+ *
+ * Copyright (C) 2016 Parav Pandit <pandit.parav@gmail.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/cgroup.h>
+#include <linux/parser.h>
+#include <linux/cgroup_rdma.h>
+
+#define RDMACG_MAX_STR "max"
+
+/*
+ * Protects list of resource pools maintained on per cgroup basis
+ * and rdma device list.
+ */
+static DEFINE_MUTEX(rdmacg_mutex);
+static LIST_HEAD(rdmacg_devices);
+
+enum rdmacg_file_type {
+	RDMACG_RESOURCE_TYPE_MAX,
+	RDMACG_RESOURCE_TYPE_STAT,
+};
+
+/*
+ * resource table definition as to be seen by the user.
+ * Need to add entries to it when more resources are
+ * added/defined at IB verb/core layer.
+ */
+static char const *rdmacg_resource_names[] = {
+	[RDMACG_RESOURCE_HCA_HANDLE]	= "hca_handle",
+	[RDMACG_RESOURCE_HCA_OBJECT]	= "hca_object",
+};
+
+/* resource tracker for each resource of rdma cgroup */
+struct rdmacg_resource {
+	int max;
+	int usage;
+};
+
+/*
+ * resource pool object which represents per cgroup, per device
+ * resources. There are multiple instances of this object per cgroup,
+ * therefore it cannot be embedded within rdma_cgroup structure. It
+ * is maintained as list.
+ */
+struct rdmacg_resource_pool {
+	struct rdmacg_device	*device;
+	struct rdmacg_resource	resources[RDMACG_RESOURCE_MAX];
+
+	struct list_head	cg_node;
+	struct list_head	dev_node;
+
+	/* count active user tasks of this pool */
+	u64			usage_sum;
+	/* total number counts which are set to max */
+	int			num_max_cnt;
+};
+
+static struct rdma_cgroup *css_rdmacg(struct cgroup_subsys_state *css)
+{
+	return container_of(css, struct rdma_cgroup, css);
+}
+
+static struct rdma_cgroup *parent_rdmacg(struct rdma_cgroup *cg)
+{
+	return css_rdmacg(cg->css.parent);
+}
+
+static inline struct rdma_cgroup *get_current_rdmacg(void)
+{
+	return css_rdmacg(task_get_css(current, rdma_cgrp_id));
+}
+
+static void set_resource_limit(struct rdmacg_resource_pool *rpool,
+			       int index, int new_max)
+{
+	if (new_max == S32_MAX) {
+		if (rpool->resources[index].max != S32_MAX)
+			rpool->num_max_cnt++;
+	} else {
+		if (rpool->resources[index].max == S32_MAX)
+			rpool->num_max_cnt--;
+	}
+	rpool->resources[index].max = new_max;
+}
+
+static void set_all_resource_max_limit(struct rdmacg_resource_pool *rpool)
+{
+	int i;
+
+	for (i = 0; i < RDMACG_RESOURCE_MAX; i++)
+		set_resource_limit(rpool, i, S32_MAX);
+}
+
+static void free_cg_rpool_locked(struct rdmacg_resource_pool *rpool)
+{
+	lockdep_assert_held(&rdmacg_mutex);
+
+	list_del(&rpool->cg_node);
+	list_del(&rpool->dev_node);
+	kfree(rpool);
+}
+
+static struct rdmacg_resource_pool *
+find_cg_rpool_locked(struct rdma_cgroup *cg,
+		     struct rdmacg_device *device)
+
+{
+	struct rdmacg_resource_pool *pool;
+
+	lockdep_assert_held(&rdmacg_mutex);
+
+	list_for_each_entry(pool, &cg->rpools, cg_node)
+		if (pool->device == device)
+			return pool;
+
+	return NULL;
+}
+
+static struct rdmacg_resource_pool *
+get_cg_rpool_locked(struct rdma_cgroup *cg, struct rdmacg_device *device)
+{
+	struct rdmacg_resource_pool *rpool;
+
+	rpool = find_cg_rpool_locked(cg, device);
+	if (rpool)
+		return rpool;
+
+	rpool = kzalloc(sizeof(*rpool), GFP_KERNEL);
+	if (!rpool)
+		return ERR_PTR(-ENOMEM);
+
+	rpool->device = device;
+	set_all_resource_max_limit(rpool);
+
+	INIT_LIST_HEAD(&rpool->cg_node);
+	INIT_LIST_HEAD(&rpool->dev_node);
+	list_add_tail(&rpool->cg_node, &cg->rpools);
+	list_add_tail(&rpool->dev_node, &device->rpools);
+	return rpool;
+}
+
+/**
+ * uncharge_cg_locked - uncharge resource for rdma cgroup
+ * @cg: pointer to cg to uncharge and all parents in hierarchy
+ * @device: pointer to rdmacg device
+ * @index: index of the resource to uncharge in cg (resource pool)
+ *
+ * It also frees the resource pool which was created as part of
+ * charging operation when there are no resources attached to
+ * resource pool.
+ */
+static void
+uncharge_cg_locked(struct rdma_cgroup *cg,
+		   struct rdmacg_device *device,
+		   enum rdmacg_resource_type index)
+{
+	struct rdmacg_resource_pool *rpool;
+
+	rpool = find_cg_rpool_locked(cg, device);
+
+	/*
+	 * rpool cannot be null at this stage. Let kernel operate in case
+	 * if there a bug in IB stack or rdma controller, instead of crashing
+	 * the system.
+	 */
+	if (unlikely(!rpool)) {
+		pr_warn("Invalid device %p or rdma cgroup %p\n", cg, device);
+		return;
+	}
+
+	rpool->resources[index].usage--;
+
+	/*
+	 * A negative count (or overflow) is invalid,
+	 * it indicates a bug in the rdma controller.
+	 */
+	WARN_ON_ONCE(rpool->resources[index].usage < 0);
+	rpool->usage_sum--;
+	if (rpool->usage_sum == 0 &&
+	    rpool->num_max_cnt == RDMACG_RESOURCE_MAX) {
+		/*
+		 * No user of the rpool and all entries are set to max, so
+		 * safe to delete this rpool.
+		 */
+		free_cg_rpool_locked(rpool);
+	}
+}
+
+/**
+ * rdmacg_uncharge_hierarchy - hierarchically uncharge rdma resource count
+ * @device: pointer to rdmacg device
+ * @stop_cg: while traversing hirerchy, when meet with stop_cg cgroup
+ *           stop uncharging
+ * @index: index of the resource to uncharge in cg in given resource pool
+ */
+static void rdmacg_uncharge_hierarchy(struct rdma_cgroup *cg,
+				     struct rdmacg_device *device,
+				     struct rdma_cgroup *stop_cg,
+				     enum rdmacg_resource_type index)
+{
+	struct rdma_cgroup *p;
+
+	mutex_lock(&rdmacg_mutex);
+
+	for (p = cg; p != stop_cg; p = parent_rdmacg(p))
+		uncharge_cg_locked(p, device, index);
+
+	mutex_unlock(&rdmacg_mutex);
+
+	css_put(&cg->css);
+}
+
+/**
+ * rdmacg_uncharge - hierarchically uncharge rdma resource count
+ * @device: pointer to rdmacg device
+ * @index: index of the resource to uncharge in cgroup in given resource pool
+ */
+void rdmacg_uncharge(struct rdma_cgroup *cg,
+		     struct rdmacg_device *device,
+		     enum rdmacg_resource_type index)
+{
+	if (index >= RDMACG_RESOURCE_MAX)
+		return;
+
+	rdmacg_uncharge_hierarchy(cg, device, NULL, index);
+}
+EXPORT_SYMBOL(rdmacg_uncharge);
+
+/**
+ * rdmacg_try_charge - hierarchically try to charge the rdma resource
+ * @rdmacg: pointer to rdma cgroup which will own this resource
+ * @device: pointer to rdmacg device
+ * @index: index of the resource to charge in cgroup (resource pool)
+ *
+ * This function follows charging resource in hierarchical way.
+ * It will fail if the charge would cause the new value to exceed the
+ * hierarchical limit.
+ * Returns 0 if the charge succeeded, otherwise -EAGAIN, -ENOMEM or -EINVAL.
+ * Returns pointer to rdmacg for this resource when charging is successful.
+ *
+ * Charger needs to account resources on two criteria.
+ * (a) per cgroup & (b) per device resource usage.
+ * Per cgroup resource usage ensures that tasks of cgroup doesn't cross
+ * the configured limits. Per device provides granular configuration
+ * in multi device usage. It allocates resource pool in the hierarchy
+ * for each parent it come across for first resource. Later on resource
+ * pool will be available. Therefore it will be much faster thereon
+ * to charge/uncharge.
+ */
+int rdmacg_try_charge(struct rdma_cgroup **rdmacg,
+		      struct rdmacg_device *device,
+		      enum rdmacg_resource_type index)
+{
+	struct rdma_cgroup *cg, *p;
+	struct rdmacg_resource_pool *rpool;
+	s64 new;
+	int ret = 0;
+
+	if (index >= RDMACG_RESOURCE_MAX)
+		return -EINVAL;
+
+	/*
+	 * hold on to css, as cgroup can be removed but resource
+	 * accounting happens on css.
+	 */
+	cg = get_current_rdmacg();
+
+	mutex_lock(&rdmacg_mutex);
+	for (p = cg; p; p = parent_rdmacg(p)) {
+		rpool = get_cg_rpool_locked(p, device);
+		if (IS_ERR(rpool)) {
+			ret = PTR_ERR(rpool);
+			goto err;
+		} else {
+			new = rpool->resources[index].usage + 1;
+			if (new > rpool->resources[index].max) {
+				ret = -EAGAIN;
+				goto err;
+			} else {
+				rpool->resources[index].usage = new;
+				rpool->usage_sum++;
+			}
+		}
+	}
+	mutex_unlock(&rdmacg_mutex);
+
+	*rdmacg = cg;
+	return 0;
+
+err:
+	mutex_unlock(&rdmacg_mutex);
+	rdmacg_uncharge_hierarchy(cg, device, p, index);
+	return ret;
+}
+EXPORT_SYMBOL(rdmacg_try_charge);
+
+/**
+ * rdmacg_register_device - register rdmacg device to rdma controller.
+ * @device: pointer to rdmacg device whose resources need to be accounted.
+ *
+ * If IB stack wish a device to participate in rdma cgroup resource
+ * tracking, it must invoke this API to register with rdma cgroup before
+ * any user space application can start using the RDMA resources.
+ */
+void rdmacg_register_device(struct rdmacg_device *device)
+{
+	INIT_LIST_HEAD(&device->dev_node);
+	INIT_LIST_HEAD(&device->rpools);
+
+	mutex_lock(&rdmacg_mutex);
+	list_add_tail(&device->dev_node, &rdmacg_devices);
+	mutex_unlock(&rdmacg_mutex);
+}
+EXPORT_SYMBOL(rdmacg_register_device);
+
+/**
+ * rdmacg_unregister_device - unregister rdmacg device from rdma controller.
+ * @device: pointer to rdmacg device which was previously registered with rdma
+ *          controller using rdmacg_register_device().
+ *
+ * IB stack must invoke this after all the resources of the IB device
+ * are destroyed and after ensuring that no more resources will be created
+ * when this API is invoked.
+ */
+void rdmacg_unregister_device(struct rdmacg_device *device)
+{
+	struct rdmacg_resource_pool *rpool, *tmp;
+
+	/*
+	 * Synchronize with any active resource settings,
+	 * usage query happening via configfs.
+	 */
+	mutex_lock(&rdmacg_mutex);
+	list_del_init(&device->dev_node);
+
+	/*
+	 * Now that this device is off the cgroup list, its safe to free
+	 * all the rpool resources.
+	 */
+	list_for_each_entry_safe(rpool, tmp, &device->rpools, dev_node)
+		free_cg_rpool_locked(rpool);
+
+	mutex_unlock(&rdmacg_mutex);
+}
+EXPORT_SYMBOL(rdmacg_unregister_device);
+
+static int parse_resource(char *c, int *intval)
+{
+	substring_t argstr;
+	char *name, *value = c;
+	size_t len;
+	int ret, i;
+
+	name = strsep(&value, "=");
+	if (!name || !value)
+		return -EINVAL;
+
+	i = match_string(rdmacg_resource_names, RDMACG_RESOURCE_MAX, name);
+	if (i < 0)
+		return i;
+
+	len = strlen(value);
+
+	argstr.from = value;
+	argstr.to = value + len;
+
+	ret = match_int(&argstr, intval);
+	if (ret >= 0) {
+		if (*intval < 0)
+			return -EINVAL;
+		return i;
+	}
+	if (strncmp(value, RDMACG_MAX_STR, len) == 0) {
+		*intval = S32_MAX;
+		return i;
+	}
+	return -EINVAL;
+}
+
+static int rdmacg_parse_limits(char *options,
+			       int *new_limits, unsigned long *enables)
+{
+	char *c;
+	int err = -EINVAL;
+
+	/* parse resource options */
+	while ((c = strsep(&options, " ")) != NULL) {
+		int index, intval;
+
+		index = parse_resource(c, &intval);
+		if (index < 0)
+			goto err;
+
+		new_limits[index] = intval;
+		*enables |= BIT(index);
+	}
+	return 0;
+
+err:
+	return err;
+}
+
+static struct rdmacg_device *rdmacg_get_device_locked(const char *name)
+{
+	struct rdmacg_device *device;
+
+	lockdep_assert_held(&rdmacg_mutex);
+
+	list_for_each_entry(device, &rdmacg_devices, dev_node)
+		if (!strcmp(name, device->name))
+			return device;
+
+	return NULL;
+}
+
+static ssize_t rdmacg_resource_set_max(struct kernfs_open_file *of,
+				       char *buf, size_t nbytes, loff_t off)
+{
+	struct rdma_cgroup *cg = css_rdmacg(of_css(of));
+	const char *dev_name;
+	struct rdmacg_resource_pool *rpool;
+	struct rdmacg_device *device;
+	char *options = strstrip(buf);
+	int *new_limits;
+	unsigned long enables = 0;
+	int i = 0, ret = 0;
+
+	/* extract the device name first */
+	dev_name = strsep(&options, " ");
+	if (!dev_name) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	new_limits = kcalloc(RDMACG_RESOURCE_MAX, sizeof(int), GFP_KERNEL);
+	if (!new_limits) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = rdmacg_parse_limits(options, new_limits, &enables);
+	if (ret)
+		goto parse_err;
+
+	/* acquire lock to synchronize with hot plug devices */
+	mutex_lock(&rdmacg_mutex);
+
+	device = rdmacg_get_device_locked(dev_name);
+	if (!device) {
+		ret = -ENODEV;
+		goto dev_err;
+	}
+
+	rpool = get_cg_rpool_locked(cg, device);
+	if (IS_ERR(rpool)) {
+		ret = PTR_ERR(rpool);
+		goto dev_err;
+	}
+
+	/* now set the new limits of the rpool */
+	for_each_set_bit(i, &enables, RDMACG_RESOURCE_MAX)
+		set_resource_limit(rpool, i, new_limits[i]);
+
+	if (rpool->usage_sum == 0 &&
+	    rpool->num_max_cnt == RDMACG_RESOURCE_MAX) {
+		/*
+		 * No user of the rpool and all entries are set to max, so
+		 * safe to delete this rpool.
+		 */
+		free_cg_rpool_locked(rpool);
+	}
+
+dev_err:
+	mutex_unlock(&rdmacg_mutex);
+
+parse_err:
+	kfree(new_limits);
+
+err:
+	return ret ?: nbytes;
+}
+
+static void print_rpool_values(struct seq_file *sf,
+			       struct rdmacg_resource_pool *rpool)
+{
+	enum rdmacg_file_type sf_type;
+	int i;
+	u32 value;
+
+	sf_type = seq_cft(sf)->private;
+
+	for (i = 0; i < RDMACG_RESOURCE_MAX; i++) {
+		seq_puts(sf, rdmacg_resource_names[i]);
+		seq_putc(sf, '=');
+		if (sf_type == RDMACG_RESOURCE_TYPE_MAX) {
+			if (rpool)
+				value = rpool->resources[i].max;
+			else
+				value = S32_MAX;
+		} else {
+			if (rpool)
+				value = rpool->resources[i].usage;
+			else
+				value = 0;
+		}
+
+		if (value == S32_MAX)
+			seq_puts(sf, RDMACG_MAX_STR);
+		else
+			seq_printf(sf, "%d", value);
+		seq_putc(sf, ' ');
+	}
+}
+
+static int rdmacg_resource_read(struct seq_file *sf, void *v)
+{
+	struct rdmacg_device *device;
+	struct rdmacg_resource_pool *rpool;
+	struct rdma_cgroup *cg = css_rdmacg(seq_css(sf));
+
+	mutex_lock(&rdmacg_mutex);
+
+	list_for_each_entry(device, &rdmacg_devices, dev_node) {
+		seq_printf(sf, "%s ", device->name);
+
+		rpool = find_cg_rpool_locked(cg, device);
+		print_rpool_values(sf, rpool);
+
+		seq_putc(sf, '\n');
+	}
+
+	mutex_unlock(&rdmacg_mutex);
+	return 0;
+}
+
+static struct cftype rdmacg_files[] = {
+	{
+		.name = "max",
+		.write = rdmacg_resource_set_max,
+		.seq_show = rdmacg_resource_read,
+		.private = RDMACG_RESOURCE_TYPE_MAX,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{
+		.name = "current",
+		.seq_show = rdmacg_resource_read,
+		.private = RDMACG_RESOURCE_TYPE_STAT,
+		.flags = CFTYPE_NOT_ON_ROOT,
+	},
+	{ }	/* terminate */
+};
+
+static struct cgroup_subsys_state *
+rdmacg_css_alloc(struct cgroup_subsys_state *parent)
+{
+	struct rdma_cgroup *cg;
+
+	cg = kzalloc(sizeof(*cg), GFP_KERNEL);
+	if (!cg)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&cg->rpools);
+	return &cg->css;
+}
+
+static void rdmacg_css_free(struct cgroup_subsys_state *css)
+{
+	struct rdma_cgroup *cg = css_rdmacg(css);
+
+	kfree(cg);
+}
+
+/**
+ * rdmacg_css_offline - cgroup css_offline callback
+ * @css: css of interest
+ *
+ * This function is called when @css is about to go away and responsible
+ * for shooting down all rdmacg associated with @css. As part of that it
+ * marks all the resource pool entries to max value, so that when resources are
+ * uncharged, associated resource pool can be freed as well.
+ */
+static void rdmacg_css_offline(struct cgroup_subsys_state *css)
+{
+	struct rdma_cgroup *cg = css_rdmacg(css);
+	struct rdmacg_resource_pool *rpool;
+
+	mutex_lock(&rdmacg_mutex);
+
+	list_for_each_entry(rpool, &cg->rpools, cg_node)
+		set_all_resource_max_limit(rpool);
+
+	mutex_unlock(&rdmacg_mutex);
+}
+
+struct cgroup_subsys rdma_cgrp_subsys = {
+	.css_alloc	= rdmacg_css_alloc,
+	.css_free	= rdmacg_css_free,
+	.css_offline	= rdmacg_css_offline,
+	.legacy_cftypes	= rdmacg_files,
+	.dfl_cftypes	= rdmacg_files,
+};
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
new file mode 100644
index 000000000..7006fc8dd
--- /dev/null
+++ b/kernel/cgroup/rstat.c
@@ -0,0 +1,549 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include "cgroup-internal.h"
+
+#include <linux/sched/cputime.h>
+
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/btf_ids.h>
+
+static DEFINE_SPINLOCK(cgroup_rstat_lock);
+static DEFINE_PER_CPU(raw_spinlock_t, cgroup_rstat_cpu_lock);
+
+static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu);
+
+static struct cgroup_rstat_cpu *cgroup_rstat_cpu(struct cgroup *cgrp, int cpu)
+{
+	return per_cpu_ptr(cgrp->rstat_cpu, cpu);
+}
+
+/**
+ * cgroup_rstat_updated - keep track of updated rstat_cpu
+ * @cgrp: target cgroup
+ * @cpu: cpu on which rstat_cpu was updated
+ *
+ * @cgrp's rstat_cpu on @cpu was updated.  Put it on the parent's matching
+ * rstat_cpu->updated_children list.  See the comment on top of
+ * cgroup_rstat_cpu definition for details.
+ */
+void cgroup_rstat_updated(struct cgroup *cgrp, int cpu)
+{
+	raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu);
+	unsigned long flags;
+
+	/*
+	 * Speculative already-on-list test. This may race leading to
+	 * temporary inaccuracies, which is fine.
+	 *
+	 * Because @parent's updated_children is terminated with @parent
+	 * instead of NULL, we can tell whether @cgrp is on the list by
+	 * testing the next pointer for NULL.
+	 */
+	if (data_race(cgroup_rstat_cpu(cgrp, cpu)->updated_next))
+		return;
+
+	raw_spin_lock_irqsave(cpu_lock, flags);
+
+	/* put @cgrp and all ancestors on the corresponding updated lists */
+	while (true) {
+		struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
+		struct cgroup *parent = cgroup_parent(cgrp);
+		struct cgroup_rstat_cpu *prstatc;
+
+		/*
+		 * Both additions and removals are bottom-up.  If a cgroup
+		 * is already in the tree, all ancestors are.
+		 */
+		if (rstatc->updated_next)
+			break;
+
+		/* Root has no parent to link it to, but mark it busy */
+		if (!parent) {
+			rstatc->updated_next = cgrp;
+			break;
+		}
+
+		prstatc = cgroup_rstat_cpu(parent, cpu);
+		rstatc->updated_next = prstatc->updated_children;
+		prstatc->updated_children = cgrp;
+
+		cgrp = parent;
+	}
+
+	raw_spin_unlock_irqrestore(cpu_lock, flags);
+}
+
+/**
+ * cgroup_rstat_cpu_pop_updated - iterate and dismantle rstat_cpu updated tree
+ * @pos: current position
+ * @root: root of the tree to traversal
+ * @cpu: target cpu
+ *
+ * Walks the updated rstat_cpu tree on @cpu from @root.  %NULL @pos starts
+ * the traversal and %NULL return indicates the end.  During traversal,
+ * each returned cgroup is unlinked from the tree.  Must be called with the
+ * matching cgroup_rstat_cpu_lock held.
+ *
+ * The only ordering guarantee is that, for a parent and a child pair
+ * covered by a given traversal, if a child is visited, its parent is
+ * guaranteed to be visited afterwards.
+ */
+static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos,
+						   struct cgroup *root, int cpu)
+{
+	struct cgroup_rstat_cpu *rstatc;
+	struct cgroup *parent;
+
+	if (pos == root)
+		return NULL;
+
+	/*
+	 * We're gonna walk down to the first leaf and visit/remove it.  We
+	 * can pick whatever unvisited node as the starting point.
+	 */
+	if (!pos) {
+		pos = root;
+		/* return NULL if this subtree is not on-list */
+		if (!cgroup_rstat_cpu(pos, cpu)->updated_next)
+			return NULL;
+	} else {
+		pos = cgroup_parent(pos);
+	}
+
+	/* walk down to the first leaf */
+	while (true) {
+		rstatc = cgroup_rstat_cpu(pos, cpu);
+		if (rstatc->updated_children == pos)
+			break;
+		pos = rstatc->updated_children;
+	}
+
+	/*
+	 * Unlink @pos from the tree.  As the updated_children list is
+	 * singly linked, we have to walk it to find the removal point.
+	 * However, due to the way we traverse, @pos will be the first
+	 * child in most cases. The only exception is @root.
+	 */
+	parent = cgroup_parent(pos);
+	if (parent) {
+		struct cgroup_rstat_cpu *prstatc;
+		struct cgroup **nextp;
+
+		prstatc = cgroup_rstat_cpu(parent, cpu);
+		nextp = &prstatc->updated_children;
+		while (*nextp != pos) {
+			struct cgroup_rstat_cpu *nrstatc;
+
+			nrstatc = cgroup_rstat_cpu(*nextp, cpu);
+			WARN_ON_ONCE(*nextp == parent);
+			nextp = &nrstatc->updated_next;
+		}
+		*nextp = rstatc->updated_next;
+	}
+
+	rstatc->updated_next = NULL;
+	return pos;
+}
+
+/*
+ * A hook for bpf stat collectors to attach to and flush their stats.
+ * Together with providing bpf kfuncs for cgroup_rstat_updated() and
+ * cgroup_rstat_flush(), this enables a complete workflow where bpf progs that
+ * collect cgroup stats can integrate with rstat for efficient flushing.
+ *
+ * A static noinline declaration here could cause the compiler to optimize away
+ * the function. A global noinline declaration will keep the definition, but may
+ * optimize away the callsite. Therefore, __weak is needed to ensure that the
+ * call is still emitted, by telling the compiler that we don't know what the
+ * function might eventually be.
+ *
+ * __diag_* below are needed to dismiss the missing prototype warning.
+ */
+__diag_push();
+__diag_ignore_all("-Wmissing-prototypes",
+		  "kfuncs which will be used in BPF programs");
+
+__weak noinline void bpf_rstat_flush(struct cgroup *cgrp,
+				     struct cgroup *parent, int cpu)
+{
+}
+
+__diag_pop();
+
+/* see cgroup_rstat_flush() */
+static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep)
+	__releases(&cgroup_rstat_lock) __acquires(&cgroup_rstat_lock)
+{
+	int cpu;
+
+	lockdep_assert_held(&cgroup_rstat_lock);
+
+	for_each_possible_cpu(cpu) {
+		raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock,
+						       cpu);
+		struct cgroup *pos = NULL;
+		unsigned long flags;
+
+		/*
+		 * The _irqsave() is needed because cgroup_rstat_lock is
+		 * spinlock_t which is a sleeping lock on PREEMPT_RT. Acquiring
+		 * this lock with the _irq() suffix only disables interrupts on
+		 * a non-PREEMPT_RT kernel. The raw_spinlock_t below disables
+		 * interrupts on both configurations. The _irqsave() ensures
+		 * that interrupts are always disabled and later restored.
+		 */
+		raw_spin_lock_irqsave(cpu_lock, flags);
+		while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu))) {
+			struct cgroup_subsys_state *css;
+
+			cgroup_base_stat_flush(pos, cpu);
+			bpf_rstat_flush(pos, cgroup_parent(pos), cpu);
+
+			rcu_read_lock();
+			list_for_each_entry_rcu(css, &pos->rstat_css_list,
+						rstat_css_node)
+				css->ss->css_rstat_flush(css, cpu);
+			rcu_read_unlock();
+		}
+		raw_spin_unlock_irqrestore(cpu_lock, flags);
+
+		/* if @may_sleep, play nice and yield if necessary */
+		if (may_sleep && (need_resched() ||
+				  spin_needbreak(&cgroup_rstat_lock))) {
+			spin_unlock_irq(&cgroup_rstat_lock);
+			if (!cond_resched())
+				cpu_relax();
+			spin_lock_irq(&cgroup_rstat_lock);
+		}
+	}
+}
+
+/**
+ * cgroup_rstat_flush - flush stats in @cgrp's subtree
+ * @cgrp: target cgroup
+ *
+ * Collect all per-cpu stats in @cgrp's subtree into the global counters
+ * and propagate them upwards.  After this function returns, all cgroups in
+ * the subtree have up-to-date ->stat.
+ *
+ * This also gets all cgroups in the subtree including @cgrp off the
+ * ->updated_children lists.
+ *
+ * This function may block.
+ */
+void cgroup_rstat_flush(struct cgroup *cgrp)
+{
+	might_sleep();
+
+	spin_lock_irq(&cgroup_rstat_lock);
+	cgroup_rstat_flush_locked(cgrp, true);
+	spin_unlock_irq(&cgroup_rstat_lock);
+}
+
+/**
+ * cgroup_rstat_flush_irqsafe - irqsafe version of cgroup_rstat_flush()
+ * @cgrp: target cgroup
+ *
+ * This function can be called from any context.
+ */
+void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&cgroup_rstat_lock, flags);
+	cgroup_rstat_flush_locked(cgrp, false);
+	spin_unlock_irqrestore(&cgroup_rstat_lock, flags);
+}
+
+/**
+ * cgroup_rstat_flush_hold - flush stats in @cgrp's subtree and hold
+ * @cgrp: target cgroup
+ *
+ * Flush stats in @cgrp's subtree and prevent further flushes.  Must be
+ * paired with cgroup_rstat_flush_release().
+ *
+ * This function may block.
+ */
+void cgroup_rstat_flush_hold(struct cgroup *cgrp)
+	__acquires(&cgroup_rstat_lock)
+{
+	might_sleep();
+	spin_lock_irq(&cgroup_rstat_lock);
+	cgroup_rstat_flush_locked(cgrp, true);
+}
+
+/**
+ * cgroup_rstat_flush_release - release cgroup_rstat_flush_hold()
+ */
+void cgroup_rstat_flush_release(void)
+	__releases(&cgroup_rstat_lock)
+{
+	spin_unlock_irq(&cgroup_rstat_lock);
+}
+
+int cgroup_rstat_init(struct cgroup *cgrp)
+{
+	int cpu;
+
+	/* the root cgrp has rstat_cpu preallocated */
+	if (!cgrp->rstat_cpu) {
+		cgrp->rstat_cpu = alloc_percpu(struct cgroup_rstat_cpu);
+		if (!cgrp->rstat_cpu)
+			return -ENOMEM;
+	}
+
+	/* ->updated_children list is self terminated */
+	for_each_possible_cpu(cpu) {
+		struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
+
+		rstatc->updated_children = cgrp;
+		u64_stats_init(&rstatc->bsync);
+	}
+
+	return 0;
+}
+
+void cgroup_rstat_exit(struct cgroup *cgrp)
+{
+	int cpu;
+
+	cgroup_rstat_flush(cgrp);
+
+	/* sanity check */
+	for_each_possible_cpu(cpu) {
+		struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
+
+		if (WARN_ON_ONCE(rstatc->updated_children != cgrp) ||
+		    WARN_ON_ONCE(rstatc->updated_next))
+			return;
+	}
+
+	free_percpu(cgrp->rstat_cpu);
+	cgrp->rstat_cpu = NULL;
+}
+
+void __init cgroup_rstat_boot(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		raw_spin_lock_init(per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu));
+}
+
+/*
+ * Functions for cgroup basic resource statistics implemented on top of
+ * rstat.
+ */
+static void cgroup_base_stat_add(struct cgroup_base_stat *dst_bstat,
+				 struct cgroup_base_stat *src_bstat)
+{
+	dst_bstat->cputime.utime += src_bstat->cputime.utime;
+	dst_bstat->cputime.stime += src_bstat->cputime.stime;
+	dst_bstat->cputime.sum_exec_runtime += src_bstat->cputime.sum_exec_runtime;
+#ifdef CONFIG_SCHED_CORE
+	dst_bstat->forceidle_sum += src_bstat->forceidle_sum;
+#endif
+}
+
+static void cgroup_base_stat_sub(struct cgroup_base_stat *dst_bstat,
+				 struct cgroup_base_stat *src_bstat)
+{
+	dst_bstat->cputime.utime -= src_bstat->cputime.utime;
+	dst_bstat->cputime.stime -= src_bstat->cputime.stime;
+	dst_bstat->cputime.sum_exec_runtime -= src_bstat->cputime.sum_exec_runtime;
+#ifdef CONFIG_SCHED_CORE
+	dst_bstat->forceidle_sum -= src_bstat->forceidle_sum;
+#endif
+}
+
+static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
+{
+	struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
+	struct cgroup *parent = cgroup_parent(cgrp);
+	struct cgroup_base_stat delta;
+	unsigned seq;
+
+	/* Root-level stats are sourced from system-wide CPU stats */
+	if (!parent)
+		return;
+
+	/* fetch the current per-cpu values */
+	do {
+		seq = __u64_stats_fetch_begin(&rstatc->bsync);
+		delta = rstatc->bstat;
+	} while (__u64_stats_fetch_retry(&rstatc->bsync, seq));
+
+	/* propagate percpu delta to global */
+	cgroup_base_stat_sub(&delta, &rstatc->last_bstat);
+	cgroup_base_stat_add(&cgrp->bstat, &delta);
+	cgroup_base_stat_add(&rstatc->last_bstat, &delta);
+
+	/* propagate global delta to parent (unless that's root) */
+	if (cgroup_parent(parent)) {
+		delta = cgrp->bstat;
+		cgroup_base_stat_sub(&delta, &cgrp->last_bstat);
+		cgroup_base_stat_add(&parent->bstat, &delta);
+		cgroup_base_stat_add(&cgrp->last_bstat, &delta);
+	}
+}
+
+static struct cgroup_rstat_cpu *
+cgroup_base_stat_cputime_account_begin(struct cgroup *cgrp, unsigned long *flags)
+{
+	struct cgroup_rstat_cpu *rstatc;
+
+	rstatc = get_cpu_ptr(cgrp->rstat_cpu);
+	*flags = u64_stats_update_begin_irqsave(&rstatc->bsync);
+	return rstatc;
+}
+
+static void cgroup_base_stat_cputime_account_end(struct cgroup *cgrp,
+						 struct cgroup_rstat_cpu *rstatc,
+						 unsigned long flags)
+{
+	u64_stats_update_end_irqrestore(&rstatc->bsync, flags);
+	cgroup_rstat_updated(cgrp, smp_processor_id());
+	put_cpu_ptr(rstatc);
+}
+
+void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec)
+{
+	struct cgroup_rstat_cpu *rstatc;
+	unsigned long flags;
+
+	rstatc = cgroup_base_stat_cputime_account_begin(cgrp, &flags);
+	rstatc->bstat.cputime.sum_exec_runtime += delta_exec;
+	cgroup_base_stat_cputime_account_end(cgrp, rstatc, flags);
+}
+
+void __cgroup_account_cputime_field(struct cgroup *cgrp,
+				    enum cpu_usage_stat index, u64 delta_exec)
+{
+	struct cgroup_rstat_cpu *rstatc;
+	unsigned long flags;
+
+	rstatc = cgroup_base_stat_cputime_account_begin(cgrp, &flags);
+
+	switch (index) {
+	case CPUTIME_USER:
+	case CPUTIME_NICE:
+		rstatc->bstat.cputime.utime += delta_exec;
+		break;
+	case CPUTIME_SYSTEM:
+	case CPUTIME_IRQ:
+	case CPUTIME_SOFTIRQ:
+		rstatc->bstat.cputime.stime += delta_exec;
+		break;
+#ifdef CONFIG_SCHED_CORE
+	case CPUTIME_FORCEIDLE:
+		rstatc->bstat.forceidle_sum += delta_exec;
+		break;
+#endif
+	default:
+		break;
+	}
+
+	cgroup_base_stat_cputime_account_end(cgrp, rstatc, flags);
+}
+
+/*
+ * compute the cputime for the root cgroup by getting the per cpu data
+ * at a global level, then categorizing the fields in a manner consistent
+ * with how it is done by __cgroup_account_cputime_field for each bit of
+ * cpu time attributed to a cgroup.
+ */
+static void root_cgroup_cputime(struct cgroup_base_stat *bstat)
+{
+	struct task_cputime *cputime = &bstat->cputime;
+	int i;
+
+	memset(bstat, 0, sizeof(*bstat));
+	for_each_possible_cpu(i) {
+		struct kernel_cpustat kcpustat;
+		u64 *cpustat = kcpustat.cpustat;
+		u64 user = 0;
+		u64 sys = 0;
+
+		kcpustat_cpu_fetch(&kcpustat, i);
+
+		user += cpustat[CPUTIME_USER];
+		user += cpustat[CPUTIME_NICE];
+		cputime->utime += user;
+
+		sys += cpustat[CPUTIME_SYSTEM];
+		sys += cpustat[CPUTIME_IRQ];
+		sys += cpustat[CPUTIME_SOFTIRQ];
+		cputime->stime += sys;
+
+		cputime->sum_exec_runtime += user;
+		cputime->sum_exec_runtime += sys;
+		cputime->sum_exec_runtime += cpustat[CPUTIME_STEAL];
+
+#ifdef CONFIG_SCHED_CORE
+		bstat->forceidle_sum += cpustat[CPUTIME_FORCEIDLE];
+#endif
+	}
+}
+
+void cgroup_base_stat_cputime_show(struct seq_file *seq)
+{
+	struct cgroup *cgrp = seq_css(seq)->cgroup;
+	u64 usage, utime, stime;
+	struct cgroup_base_stat bstat;
+#ifdef CONFIG_SCHED_CORE
+	u64 forceidle_time;
+#endif
+
+	if (cgroup_parent(cgrp)) {
+		cgroup_rstat_flush_hold(cgrp);
+		usage = cgrp->bstat.cputime.sum_exec_runtime;
+		cputime_adjust(&cgrp->bstat.cputime, &cgrp->prev_cputime,
+			       &utime, &stime);
+#ifdef CONFIG_SCHED_CORE
+		forceidle_time = cgrp->bstat.forceidle_sum;
+#endif
+		cgroup_rstat_flush_release();
+	} else {
+		root_cgroup_cputime(&bstat);
+		usage = bstat.cputime.sum_exec_runtime;
+		utime = bstat.cputime.utime;
+		stime = bstat.cputime.stime;
+#ifdef CONFIG_SCHED_CORE
+		forceidle_time = bstat.forceidle_sum;
+#endif
+	}
+
+	do_div(usage, NSEC_PER_USEC);
+	do_div(utime, NSEC_PER_USEC);
+	do_div(stime, NSEC_PER_USEC);
+#ifdef CONFIG_SCHED_CORE
+	do_div(forceidle_time, NSEC_PER_USEC);
+#endif
+
+	seq_printf(seq, "usage_usec %llu\n"
+		   "user_usec %llu\n"
+		   "system_usec %llu\n",
+		   usage, utime, stime);
+
+#ifdef CONFIG_SCHED_CORE
+	seq_printf(seq, "core_sched.force_idle_usec %llu\n", forceidle_time);
+#endif
+}
+
+/* Add bpf kfuncs for cgroup_rstat_updated() and cgroup_rstat_flush() */
+BTF_SET8_START(bpf_rstat_kfunc_ids)
+BTF_ID_FLAGS(func, cgroup_rstat_updated)
+BTF_ID_FLAGS(func, cgroup_rstat_flush, KF_SLEEPABLE)
+BTF_SET8_END(bpf_rstat_kfunc_ids)
+
+static const struct btf_kfunc_id_set bpf_rstat_kfunc_set = {
+	.owner          = THIS_MODULE,
+	.set            = &bpf_rstat_kfunc_ids,
+};
+
+static int __init bpf_rstat_kfunc_init(void)
+{
+	return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING,
+					 &bpf_rstat_kfunc_set);
+}
+late_initcall(bpf_rstat_kfunc_init);
diff --git a/kernel/compat.c b/kernel/compat.c
new file mode 100644
index 000000000..fb50f29d9
--- /dev/null
+++ b/kernel/compat.c
@@ -0,0 +1,271 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/kernel/compat.c
+ *
+ *  Kernel compatibililty routines for e.g. 32 bit syscall support
+ *  on 64 bit kernels.
+ *
+ *  Copyright (C) 2002-2003 Stephen Rothwell, IBM Corporation
+ */
+
+#include <linux/linkage.h>
+#include <linux/compat.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/signal.h>
+#include <linux/sched.h>	/* for MAX_SCHEDULE_TIMEOUT */
+#include <linux/syscalls.h>
+#include <linux/unistd.h>
+#include <linux/security.h>
+#include <linux/export.h>
+#include <linux/migrate.h>
+#include <linux/posix-timers.h>
+#include <linux/times.h>
+#include <linux/ptrace.h>
+#include <linux/gfp.h>
+
+#include <linux/uaccess.h>
+
+#ifdef __ARCH_WANT_SYS_SIGPROCMASK
+
+/*
+ * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
+ * blocked set of signals to the supplied signal set
+ */
+static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
+{
+	memcpy(blocked->sig, &set, sizeof(set));
+}
+
+COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
+		       compat_old_sigset_t __user *, nset,
+		       compat_old_sigset_t __user *, oset)
+{
+	old_sigset_t old_set, new_set;
+	sigset_t new_blocked;
+
+	old_set = current->blocked.sig[0];
+
+	if (nset) {
+		if (get_user(new_set, nset))
+			return -EFAULT;
+		new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
+
+		new_blocked = current->blocked;
+
+		switch (how) {
+		case SIG_BLOCK:
+			sigaddsetmask(&new_blocked, new_set);
+			break;
+		case SIG_UNBLOCK:
+			sigdelsetmask(&new_blocked, new_set);
+			break;
+		case SIG_SETMASK:
+			compat_sig_setmask(&new_blocked, new_set);
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		set_current_blocked(&new_blocked);
+	}
+
+	if (oset) {
+		if (put_user(old_set, oset))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+#endif
+
+int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
+{
+	struct compat_rusage r32;
+	memset(&r32, 0, sizeof(r32));
+	r32.ru_utime.tv_sec = r->ru_utime.tv_sec;
+	r32.ru_utime.tv_usec = r->ru_utime.tv_usec;
+	r32.ru_stime.tv_sec = r->ru_stime.tv_sec;
+	r32.ru_stime.tv_usec = r->ru_stime.tv_usec;
+	r32.ru_maxrss = r->ru_maxrss;
+	r32.ru_ixrss = r->ru_ixrss;
+	r32.ru_idrss = r->ru_idrss;
+	r32.ru_isrss = r->ru_isrss;
+	r32.ru_minflt = r->ru_minflt;
+	r32.ru_majflt = r->ru_majflt;
+	r32.ru_nswap = r->ru_nswap;
+	r32.ru_inblock = r->ru_inblock;
+	r32.ru_oublock = r->ru_oublock;
+	r32.ru_msgsnd = r->ru_msgsnd;
+	r32.ru_msgrcv = r->ru_msgrcv;
+	r32.ru_nsignals = r->ru_nsignals;
+	r32.ru_nvcsw = r->ru_nvcsw;
+	r32.ru_nivcsw = r->ru_nivcsw;
+	if (copy_to_user(ru, &r32, sizeof(r32)))
+		return -EFAULT;
+	return 0;
+}
+
+static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
+				    unsigned len, struct cpumask *new_mask)
+{
+	unsigned long *k;
+
+	if (len < cpumask_size())
+		memset(new_mask, 0, cpumask_size());
+	else if (len > cpumask_size())
+		len = cpumask_size();
+
+	k = cpumask_bits(new_mask);
+	return compat_get_bitmap(k, user_mask_ptr, len * 8);
+}
+
+COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
+		       unsigned int, len,
+		       compat_ulong_t __user *, user_mask_ptr)
+{
+	cpumask_var_t new_mask;
+	int retval;
+
+	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
+	if (retval)
+		goto out;
+
+	retval = sched_setaffinity(pid, new_mask);
+out:
+	free_cpumask_var(new_mask);
+	return retval;
+}
+
+COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t,  pid, unsigned int, len,
+		       compat_ulong_t __user *, user_mask_ptr)
+{
+	int ret;
+	cpumask_var_t mask;
+
+	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
+		return -EINVAL;
+	if (len & (sizeof(compat_ulong_t)-1))
+		return -EINVAL;
+
+	if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	ret = sched_getaffinity(pid, mask);
+	if (ret == 0) {
+		unsigned int retlen = min(len, cpumask_size());
+
+		if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
+			ret = -EFAULT;
+		else
+			ret = retlen;
+	}
+	free_cpumask_var(mask);
+
+	return ret;
+}
+
+/*
+ * We currently only need the following fields from the sigevent
+ * structure: sigev_value, sigev_signo, sig_notify and (sometimes
+ * sigev_notify_thread_id).  The others are handled in user mode.
+ * We also assume that copying sigev_value.sival_int is sufficient
+ * to keep all the bits of sigev_value.sival_ptr intact.
+ */
+int get_compat_sigevent(struct sigevent *event,
+		const struct compat_sigevent __user *u_event)
+{
+	memset(event, 0, sizeof(*event));
+	return (!access_ok(u_event, sizeof(*u_event)) ||
+		__get_user(event->sigev_value.sival_int,
+			&u_event->sigev_value.sival_int) ||
+		__get_user(event->sigev_signo, &u_event->sigev_signo) ||
+		__get_user(event->sigev_notify, &u_event->sigev_notify) ||
+		__get_user(event->sigev_notify_thread_id,
+			&u_event->sigev_notify_thread_id))
+		? -EFAULT : 0;
+}
+
+long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
+		       unsigned long bitmap_size)
+{
+	unsigned long nr_compat_longs;
+
+	/* align bitmap up to nearest compat_long_t boundary */
+	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
+	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
+
+	if (!user_read_access_begin(umask, bitmap_size / 8))
+		return -EFAULT;
+
+	while (nr_compat_longs > 1) {
+		compat_ulong_t l1, l2;
+		unsafe_get_user(l1, umask++, Efault);
+		unsafe_get_user(l2, umask++, Efault);
+		*mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1;
+		nr_compat_longs -= 2;
+	}
+	if (nr_compat_longs)
+		unsafe_get_user(*mask, umask++, Efault);
+	user_read_access_end();
+	return 0;
+
+Efault:
+	user_read_access_end();
+	return -EFAULT;
+}
+
+long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
+		       unsigned long bitmap_size)
+{
+	unsigned long nr_compat_longs;
+
+	/* align bitmap up to nearest compat_long_t boundary */
+	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
+	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
+
+	if (!user_write_access_begin(umask, bitmap_size / 8))
+		return -EFAULT;
+
+	while (nr_compat_longs > 1) {
+		unsigned long m = *mask++;
+		unsafe_put_user((compat_ulong_t)m, umask++, Efault);
+		unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault);
+		nr_compat_longs -= 2;
+	}
+	if (nr_compat_longs)
+		unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);
+	user_write_access_end();
+	return 0;
+Efault:
+	user_write_access_end();
+	return -EFAULT;
+}
+
+int
+get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat)
+{
+#ifdef __BIG_ENDIAN
+	compat_sigset_t v;
+	if (copy_from_user(&v, compat, sizeof(compat_sigset_t)))
+		return -EFAULT;
+	switch (_NSIG_WORDS) {
+	case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 );
+		fallthrough;
+	case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );
+		fallthrough;
+	case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );
+		fallthrough;
+	case 1: set->sig[0] = v.sig[0] | (((long)v.sig[1]) << 32 );
+	}
+#else
+	if (copy_from_user(set, compat, sizeof(compat_sigset_t)))
+		return -EFAULT;
+#endif
+	return 0;
+}
+EXPORT_SYMBOL_GPL(get_compat_sigset);
diff --git a/kernel/configs.c b/kernel/configs.c
new file mode 100644
index 000000000..a28c79c5f
--- /dev/null
+++ b/kernel/configs.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * kernel/configs.c
+ * Echo the kernel .config file used to build the kernel
+ *
+ * Copyright (C) 2002 Khalid Aziz <khalid_aziz@hp.com>
+ * Copyright (C) 2002 Randy Dunlap <rdunlap@xenotime.net>
+ * Copyright (C) 2002 Al Stone <ahs3@fc.hp.com>
+ * Copyright (C) 2002 Hewlett-Packard Company
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/init.h>
+#include <linux/uaccess.h>
+
+/*
+ * "IKCFG_ST" and "IKCFG_ED" are used to extract the config data from
+ * a binary kernel image or a module. See scripts/extract-ikconfig.
+ */
+asm (
+"	.pushsection .rodata, \"a\"		\n"
+"	.ascii \"IKCFG_ST\"			\n"
+"	.global kernel_config_data		\n"
+"kernel_config_data:				\n"
+"	.incbin \"kernel/config_data.gz\"	\n"
+"	.global kernel_config_data_end		\n"
+"kernel_config_data_end:			\n"
+"	.ascii \"IKCFG_ED\"			\n"
+"	.popsection				\n"
+);
+
+#ifdef CONFIG_IKCONFIG_PROC
+
+extern char kernel_config_data;
+extern char kernel_config_data_end;
+
+static ssize_t
+ikconfig_read_current(struct file *file, char __user *buf,
+		      size_t len, loff_t * offset)
+{
+	return simple_read_from_buffer(buf, len, offset,
+				       &kernel_config_data,
+				       &kernel_config_data_end -
+				       &kernel_config_data);
+}
+
+static const struct proc_ops config_gz_proc_ops = {
+	.proc_read	= ikconfig_read_current,
+	.proc_lseek	= default_llseek,
+};
+
+static int __init ikconfig_init(void)
+{
+	struct proc_dir_entry *entry;
+
+	/* create the current config file */
+	entry = proc_create("config.gz", S_IFREG | S_IRUGO, NULL,
+			    &config_gz_proc_ops);
+	if (!entry)
+		return -ENOMEM;
+
+	proc_set_size(entry, &kernel_config_data_end - &kernel_config_data);
+
+	return 0;
+}
+
+static void __exit ikconfig_cleanup(void)
+{
+	remove_proc_entry("config.gz", NULL);
+}
+
+module_init(ikconfig_init);
+module_exit(ikconfig_cleanup);
+
+#endif /* CONFIG_IKCONFIG_PROC */
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Randy Dunlap");
+MODULE_DESCRIPTION("Echo the kernel .config file used to build the kernel");
diff --git a/kernel/configs/android-base.config b/kernel/configs/android-base.config
new file mode 100644
index 000000000..44b0f0146
--- /dev/null
+++ b/kernel/configs/android-base.config
@@ -0,0 +1,159 @@
+#  KEEP ALPHABETICALLY SORTED
+# CONFIG_DEVMEM is not set
+# CONFIG_FHANDLE is not set
+# CONFIG_INET_LRO is not set
+# CONFIG_NFSD is not set
+# CONFIG_NFS_FS is not set
+# CONFIG_OABI_COMPAT is not set
+# CONFIG_SYSVIPC is not set
+# CONFIG_USELIB is not set
+CONFIG_ANDROID_BINDER_IPC=y
+CONFIG_ANDROID_BINDER_DEVICES=binder,hwbinder,vndbinder
+CONFIG_ANDROID_LOW_MEMORY_KILLER=y
+CONFIG_ARMV8_DEPRECATED=y
+CONFIG_ASHMEM=y
+CONFIG_AUDIT=y
+CONFIG_BLK_DEV_INITRD=y
+CONFIG_CGROUPS=y
+CONFIG_CGROUP_BPF=y
+CONFIG_CGROUP_CPUACCT=y
+CONFIG_CGROUP_DEBUG=y
+CONFIG_CGROUP_FREEZER=y
+CONFIG_CGROUP_SCHED=y
+CONFIG_CP15_BARRIER_EMULATION=y
+CONFIG_DEFAULT_SECURITY_SELINUX=y
+CONFIG_EMBEDDED=y
+CONFIG_FB=y
+CONFIG_HARDENED_USERCOPY=y
+CONFIG_HIGH_RES_TIMERS=y
+CONFIG_IKCONFIG=y
+CONFIG_IKCONFIG_PROC=y
+CONFIG_INET6_AH=y
+CONFIG_INET6_ESP=y
+CONFIG_INET6_IPCOMP=y
+CONFIG_INET=y
+CONFIG_INET_DIAG_DESTROY=y
+CONFIG_INET_ESP=y
+CONFIG_INET_XFRM_MODE_TUNNEL=y
+CONFIG_IP6_NF_FILTER=y
+CONFIG_IP6_NF_IPTABLES=y
+CONFIG_IP6_NF_MANGLE=y
+CONFIG_IP6_NF_RAW=y
+CONFIG_IP6_NF_TARGET_REJECT=y
+CONFIG_IPV6=y
+CONFIG_IPV6_MIP6=y
+CONFIG_IPV6_MULTIPLE_TABLES=y
+CONFIG_IPV6_OPTIMISTIC_DAD=y
+CONFIG_IPV6_ROUTER_PREF=y
+CONFIG_IPV6_ROUTE_INFO=y
+CONFIG_IP_ADVANCED_ROUTER=y
+CONFIG_IP_MULTICAST=y
+CONFIG_IP_MULTIPLE_TABLES=y
+CONFIG_IP_NF_ARPFILTER=y
+CONFIG_IP_NF_ARPTABLES=y
+CONFIG_IP_NF_ARP_MANGLE=y
+CONFIG_IP_NF_FILTER=y
+CONFIG_IP_NF_IPTABLES=y
+CONFIG_IP_NF_MANGLE=y
+CONFIG_IP_NF_MATCH_AH=y
+CONFIG_IP_NF_MATCH_ECN=y
+CONFIG_IP_NF_MATCH_TTL=y
+CONFIG_IP_NF_NAT=y
+CONFIG_IP_NF_RAW=y
+CONFIG_IP_NF_SECURITY=y
+CONFIG_IP_NF_TARGET_MASQUERADE=y
+CONFIG_IP_NF_TARGET_NETMAP=y
+CONFIG_IP_NF_TARGET_REDIRECT=y
+CONFIG_IP_NF_TARGET_REJECT=y
+CONFIG_MODULES=y
+CONFIG_MODULE_UNLOAD=y
+CONFIG_MODVERSIONS=y
+CONFIG_NET=y
+CONFIG_NETDEVICES=y
+CONFIG_NETFILTER=y
+CONFIG_NETFILTER_TPROXY=y
+CONFIG_NETFILTER_XT_MATCH_COMMENT=y
+CONFIG_NETFILTER_XT_MATCH_CONNLIMIT=y
+CONFIG_NETFILTER_XT_MATCH_CONNMARK=y
+CONFIG_NETFILTER_XT_MATCH_CONNTRACK=y
+CONFIG_NETFILTER_XT_MATCH_HASHLIMIT=y
+CONFIG_NETFILTER_XT_MATCH_HELPER=y
+CONFIG_NETFILTER_XT_MATCH_IPRANGE=y
+CONFIG_NETFILTER_XT_MATCH_LENGTH=y
+CONFIG_NETFILTER_XT_MATCH_LIMIT=y
+CONFIG_NETFILTER_XT_MATCH_MAC=y
+CONFIG_NETFILTER_XT_MATCH_MARK=y
+CONFIG_NETFILTER_XT_MATCH_PKTTYPE=y
+CONFIG_NETFILTER_XT_MATCH_POLICY=y
+CONFIG_NETFILTER_XT_MATCH_QUOTA=y
+CONFIG_NETFILTER_XT_MATCH_SOCKET=y
+CONFIG_NETFILTER_XT_MATCH_STATE=y
+CONFIG_NETFILTER_XT_MATCH_STATISTIC=y
+CONFIG_NETFILTER_XT_MATCH_STRING=y
+CONFIG_NETFILTER_XT_MATCH_TIME=y
+CONFIG_NETFILTER_XT_MATCH_U32=y
+CONFIG_NETFILTER_XT_TARGET_CLASSIFY=y
+CONFIG_NETFILTER_XT_TARGET_CONNMARK=y
+CONFIG_NETFILTER_XT_TARGET_CONNSECMARK=y
+CONFIG_NETFILTER_XT_TARGET_IDLETIMER=y
+CONFIG_NETFILTER_XT_TARGET_MARK=y
+CONFIG_NETFILTER_XT_TARGET_NFLOG=y
+CONFIG_NETFILTER_XT_TARGET_NFQUEUE=y
+CONFIG_NETFILTER_XT_TARGET_SECMARK=y
+CONFIG_NETFILTER_XT_TARGET_TCPMSS=y
+CONFIG_NETFILTER_XT_TARGET_TPROXY=y
+CONFIG_NETFILTER_XT_TARGET_TRACE=y
+CONFIG_NET_CLS_ACT=y
+CONFIG_NET_CLS_U32=y
+CONFIG_NET_EMATCH=y
+CONFIG_NET_EMATCH_U32=y
+CONFIG_NET_KEY=y
+CONFIG_NET_SCHED=y
+CONFIG_NET_SCH_HTB=y
+CONFIG_NF_CONNTRACK=y
+CONFIG_NF_CONNTRACK_AMANDA=y
+CONFIG_NF_CONNTRACK_EVENTS=y
+CONFIG_NF_CONNTRACK_FTP=y
+CONFIG_NF_CONNTRACK_H323=y
+CONFIG_NF_CONNTRACK_IPV4=y
+CONFIG_NF_CONNTRACK_IPV6=y
+CONFIG_NF_CONNTRACK_IRC=y
+CONFIG_NF_CONNTRACK_NETBIOS_NS=y
+CONFIG_NF_CONNTRACK_PPTP=y
+CONFIG_NF_CONNTRACK_SANE=y
+CONFIG_NF_CONNTRACK_SECMARK=y
+CONFIG_NF_CONNTRACK_TFTP=y
+CONFIG_NF_CT_NETLINK=y
+CONFIG_NF_CT_PROTO_DCCP=y
+CONFIG_NF_CT_PROTO_SCTP=y
+CONFIG_NF_CT_PROTO_UDPLITE=y
+CONFIG_NF_NAT=y
+CONFIG_NO_HZ=y
+CONFIG_PACKET=y
+CONFIG_PM_AUTOSLEEP=y
+CONFIG_PM_WAKELOCKS=y
+CONFIG_PPP=y
+CONFIG_PPP_BSDCOMP=y
+CONFIG_PPP_DEFLATE=y
+CONFIG_PPP_MPPE=y
+CONFIG_PREEMPT=y
+CONFIG_QUOTA=y
+CONFIG_RANDOMIZE_BASE=y
+CONFIG_RTC_CLASS=y
+CONFIG_RT_GROUP_SCHED=y
+CONFIG_SECCOMP=y
+CONFIG_SECURITY=y
+CONFIG_SECURITY_NETWORK=y
+CONFIG_SECURITY_SELINUX=y
+CONFIG_SETEND_EMULATION=y
+CONFIG_STAGING=y
+CONFIG_SWP_EMULATION=y
+CONFIG_SYNC=y
+CONFIG_TUN=y
+CONFIG_UNIX=y
+CONFIG_USB_GADGET=y
+CONFIG_USB_CONFIGFS=y
+CONFIG_USB_CONFIGFS_F_FS=y
+CONFIG_USB_CONFIGFS_F_MIDI=y
+CONFIG_USB_OTG_WAKELOCK=y
+CONFIG_XFRM_USER=y
diff --git a/kernel/configs/android-recommended.config b/kernel/configs/android-recommended.config
new file mode 100644
index 000000000..e400fbbc8
--- /dev/null
+++ b/kernel/configs/android-recommended.config
@@ -0,0 +1,127 @@
+#  KEEP ALPHABETICALLY SORTED
+# CONFIG_BPF_UNPRIV_DEFAULT_OFF is not set
+# CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
+# CONFIG_INPUT_MOUSE is not set
+# CONFIG_LEGACY_PTYS is not set
+# CONFIG_NF_CONNTRACK_SIP is not set
+# CONFIG_PM_WAKELOCKS_GC is not set
+# CONFIG_VT is not set
+CONFIG_ARM64_SW_TTBR0_PAN=y
+CONFIG_BACKLIGHT_LCD_SUPPORT=y
+CONFIG_BLK_DEV_DM=y
+CONFIG_BLK_DEV_LOOP=y
+CONFIG_BLK_DEV_RAM=y
+CONFIG_BLK_DEV_RAM_SIZE=8192
+CONFIG_STACKPROTECTOR_STRONG=y
+CONFIG_COMPACTION=y
+CONFIG_CPU_SW_DOMAIN_PAN=y
+CONFIG_DM_CRYPT=y
+CONFIG_DM_UEVENT=y
+CONFIG_DM_VERITY=y
+CONFIG_DM_VERITY_FEC=y
+CONFIG_DRAGONRISE_FF=y
+CONFIG_ENABLE_DEFAULT_TRACERS=y
+CONFIG_EXT4_FS=y
+CONFIG_EXT4_FS_SECURITY=y
+CONFIG_FUSE_FS=y
+CONFIG_GREENASIA_FF=y
+CONFIG_HIDRAW=y
+CONFIG_HID_A4TECH=y
+CONFIG_HID_ACRUX=y
+CONFIG_HID_ACRUX_FF=y
+CONFIG_HID_APPLE=y
+CONFIG_HID_BELKIN=y
+CONFIG_HID_CHERRY=y
+CONFIG_HID_CHICONY=y
+CONFIG_HID_CYPRESS=y
+CONFIG_HID_DRAGONRISE=y
+CONFIG_HID_ELECOM=y
+CONFIG_HID_EMS_FF=y
+CONFIG_HID_EZKEY=y
+CONFIG_HID_GREENASIA=y
+CONFIG_HID_GYRATION=y
+CONFIG_HID_HOLTEK=y
+CONFIG_HID_KENSINGTON=y
+CONFIG_HID_KEYTOUCH=y
+CONFIG_HID_KYE=y
+CONFIG_HID_LCPOWER=y
+CONFIG_HID_LOGITECH=y
+CONFIG_HID_LOGITECH_DJ=y
+CONFIG_HID_MAGICMOUSE=y
+CONFIG_HID_MICROSOFT=y
+CONFIG_HID_MONTEREY=y
+CONFIG_HID_MULTITOUCH=y
+CONFIG_HID_NTRIG=y
+CONFIG_HID_ORTEK=y
+CONFIG_HID_PANTHERLORD=y
+CONFIG_HID_PETALYNX=y
+CONFIG_HID_PICOLCD=y
+CONFIG_HID_PRIMAX=y
+CONFIG_HID_PRODIKEYS=y
+CONFIG_HID_ROCCAT=y
+CONFIG_HID_SAITEK=y
+CONFIG_HID_SAMSUNG=y
+CONFIG_HID_SMARTJOYPLUS=y
+CONFIG_HID_SONY=y
+CONFIG_HID_SPEEDLINK=y
+CONFIG_HID_SUNPLUS=y
+CONFIG_HID_THRUSTMASTER=y
+CONFIG_HID_TIVO=y
+CONFIG_HID_TOPSEED=y
+CONFIG_HID_TWINHAN=y
+CONFIG_HID_UCLOGIC=y
+CONFIG_HID_WACOM=y
+CONFIG_HID_WALTOP=y
+CONFIG_HID_WIIMOTE=y
+CONFIG_HID_ZEROPLUS=y
+CONFIG_HID_ZYDACRON=y
+CONFIG_INPUT_EVDEV=y
+CONFIG_INPUT_GPIO=y
+CONFIG_INPUT_JOYSTICK=y
+CONFIG_INPUT_MISC=y
+CONFIG_INPUT_TABLET=y
+CONFIG_INPUT_UINPUT=y
+CONFIG_JOYSTICK_XPAD=y
+CONFIG_JOYSTICK_XPAD_FF=y
+CONFIG_JOYSTICK_XPAD_LEDS=y
+CONFIG_KALLSYMS_ALL=y
+CONFIG_KSM=y
+CONFIG_LOGIG940_FF=y
+CONFIG_LOGIRUMBLEPAD2_FF=y
+CONFIG_LOGITECH_FF=y
+CONFIG_MD=y
+CONFIG_MEDIA_SUPPORT=y
+CONFIG_MSDOS_FS=y
+CONFIG_PANIC_TIMEOUT=5
+CONFIG_PANTHERLORD_FF=y
+CONFIG_PERF_EVENTS=y
+CONFIG_PM_DEBUG=y
+CONFIG_PM_RUNTIME=y
+CONFIG_PM_WAKELOCKS_LIMIT=0
+CONFIG_POWER_SUPPLY=y
+CONFIG_PSTORE=y
+CONFIG_PSTORE_CONSOLE=y
+CONFIG_PSTORE_RAM=y
+CONFIG_SCHEDSTATS=y
+CONFIG_SMARTJOYPLUS_FF=y
+CONFIG_SND=y
+CONFIG_SOUND=y
+CONFIG_STRICT_KERNEL_RWX=y
+CONFIG_SUSPEND_TIME=y
+CONFIG_TABLET_USB_ACECAD=y
+CONFIG_TABLET_USB_AIPTEK=y
+CONFIG_TABLET_USB_HANWANG=y
+CONFIG_TABLET_USB_KBTAB=y
+CONFIG_TASKSTATS=y
+CONFIG_TASK_DELAY_ACCT=y
+CONFIG_TASK_IO_ACCOUNTING=y
+CONFIG_TASK_XACCT=y
+CONFIG_TIMER_STATS=y
+CONFIG_TMPFS=y
+CONFIG_TMPFS_POSIX_ACL=y
+CONFIG_UHID=y
+CONFIG_USB_ANNOUNCE_NEW_DEVICES=y
+CONFIG_USB_EHCI_HCD=y
+CONFIG_USB_HIDDEV=y
+CONFIG_USB_USBNET=y
+CONFIG_VFAT_FS=y
diff --git a/kernel/configs/debug.config b/kernel/configs/debug.config
new file mode 100644
index 000000000..e8db8d938
--- /dev/null
+++ b/kernel/configs/debug.config
@@ -0,0 +1,106 @@
+# The config is based on running daily CI for enterprise Linux distros to
+# seek regressions on linux-next builds on different bare-metal and virtual
+# platforms. It can be used for example,
+#
+# $ make ARCH=arm64 defconfig debug.config
+#
+# Keep alphabetically sorted inside each section.
+#
+# printk and dmesg options
+#
+CONFIG_DEBUG_BUGVERBOSE=y
+CONFIG_DYNAMIC_DEBUG=y
+CONFIG_PRINTK_CALLER=y
+CONFIG_PRINTK_TIME=y
+CONFIG_SYMBOLIC_ERRNAME=y
+#
+# Compile-time checks and compiler options
+#
+CONFIG_DEBUG_INFO=y
+CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
+CONFIG_DEBUG_SECTION_MISMATCH=y
+CONFIG_FRAME_WARN=2048
+CONFIG_SECTION_MISMATCH_WARN_ONLY=y
+#
+# Generic Kernel Debugging Instruments
+#
+# CONFIG_UBSAN_ALIGNMENT is not set
+# CONFIG_UBSAN_DIV_ZERO is not set
+# CONFIG_UBSAN_TRAP is not set
+# CONFIG_WARN_ALL_UNSEEDED_RANDOM is not set
+CONFIG_DEBUG_FS=y
+CONFIG_DEBUG_FS_ALLOW_ALL=y
+CONFIG_DEBUG_IRQFLAGS=y
+CONFIG_UBSAN=y
+CONFIG_UBSAN_BOOL=y
+CONFIG_UBSAN_BOUNDS=y
+CONFIG_UBSAN_ENUM=y
+CONFIG_UBSAN_SHIFT=y
+CONFIG_UBSAN_UNREACHABLE=y
+#
+# Memory Debugging
+#
+# CONFIG_DEBUG_PAGEALLOC is not set
+# CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF is not set
+# CONFIG_DEBUG_RODATA_TEST is not set
+# CONFIG_DEBUG_WX is not set
+# CONFIG_KFENCE is not set
+# CONFIG_PAGE_POISONING is not set
+# CONFIG_SLUB_STATS is not set
+CONFIG_PAGE_EXTENSION=y
+CONFIG_PAGE_OWNER=y
+CONFIG_DEBUG_KMEMLEAK=y
+CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN=y
+CONFIG_DEBUG_OBJECTS=y
+CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT=1
+CONFIG_DEBUG_OBJECTS_FREE=y
+CONFIG_DEBUG_OBJECTS_PERCPU_COUNTER=y
+CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
+CONFIG_DEBUG_OBJECTS_TIMERS=y
+CONFIG_DEBUG_OBJECTS_WORK=y
+CONFIG_DEBUG_PER_CPU_MAPS=y
+CONFIG_DEBUG_STACK_USAGE=y
+CONFIG_DEBUG_VIRTUAL=y
+CONFIG_DEBUG_VM=y
+CONFIG_DEBUG_VM_PGFLAGS=y
+CONFIG_DEBUG_VM_RB=y
+CONFIG_DEBUG_VM_VMACACHE=y
+CONFIG_GENERIC_PTDUMP=y
+CONFIG_KASAN=y
+CONFIG_KASAN_GENERIC=y
+CONFIG_KASAN_INLINE=y
+CONFIG_KASAN_VMALLOC=y
+CONFIG_PTDUMP_DEBUGFS=y
+CONFIG_SCHED_STACK_END_CHECK=y
+CONFIG_SLUB_DEBUG_ON=y
+#
+# Debug Oops, Lockups and Hangs
+#
+# CONFIG_BOOTPARAM_HUNG_TASK_PANIC is not set
+# CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC is not set
+CONFIG_DEBUG_ATOMIC_SLEEP=y
+CONFIG_DETECT_HUNG_TASK=y
+CONFIG_PANIC_ON_OOPS=y
+CONFIG_PANIC_TIMEOUT=0
+CONFIG_SOFTLOCKUP_DETECTOR=y
+#
+# Lock Debugging (spinlocks, mutexes, etc...)
+#
+# CONFIG_PROVE_RAW_LOCK_NESTING is not set
+CONFIG_PROVE_LOCKING=y
+#
+# Debug kernel data structures
+#
+CONFIG_BUG_ON_DATA_CORRUPTION=y
+#
+# RCU Debugging
+#
+CONFIG_PROVE_RCU=y
+CONFIG_PROVE_RCU_LIST=y
+#
+# Tracers
+#
+CONFIG_BRANCH_PROFILE_NONE=y
+CONFIG_DYNAMIC_FTRACE=y
+CONFIG_FTRACE=y
+CONFIG_FUNCTION_TRACER=y
diff --git a/kernel/configs/kvm_guest.config b/kernel/configs/kvm_guest.config
new file mode 100644
index 000000000..208481d91
--- /dev/null
+++ b/kernel/configs/kvm_guest.config
@@ -0,0 +1,34 @@
+CONFIG_NET=y
+CONFIG_NET_CORE=y
+CONFIG_NETDEVICES=y
+CONFIG_BLOCK=y
+CONFIG_BLK_DEV=y
+CONFIG_NETWORK_FILESYSTEMS=y
+CONFIG_INET=y
+CONFIG_TTY=y
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_IP_PNP=y
+CONFIG_IP_PNP_DHCP=y
+CONFIG_BINFMT_ELF=y
+CONFIG_PCI=y
+CONFIG_PCI_MSI=y
+CONFIG_DEBUG_KERNEL=y
+CONFIG_VIRTUALIZATION=y
+CONFIG_HYPERVISOR_GUEST=y
+CONFIG_PARAVIRT=y
+CONFIG_KVM_GUEST=y
+CONFIG_S390_GUEST=y
+CONFIG_VIRTIO=y
+CONFIG_VIRTIO_MENU=y
+CONFIG_VIRTIO_PCI=y
+CONFIG_VIRTIO_BLK=y
+CONFIG_VIRTIO_CONSOLE=y
+CONFIG_VIRTIO_NET=y
+CONFIG_9P_FS=y
+CONFIG_NET_9P=y
+CONFIG_NET_9P_VIRTIO=y
+CONFIG_SCSI_LOWLEVEL=y
+CONFIG_SCSI_VIRTIO=y
+CONFIG_VIRTIO_INPUT=y
+CONFIG_DRM_VIRTIO_GPU=y
diff --git a/kernel/configs/nopm.config b/kernel/configs/nopm.config
new file mode 100644
index 000000000..81ff07863
--- /dev/null
+++ b/kernel/configs/nopm.config
@@ -0,0 +1,15 @@
+CONFIG_PM=n
+CONFIG_SUSPEND=n
+CONFIG_HIBERNATION=n
+
+# Triggers PM on OMAP
+CONFIG_CPU_IDLE=n
+
+# Triggers enablement via hibernate callbacks
+CONFIG_XEN=n
+
+# ARM/ARM64 architectures that select PM unconditionally
+CONFIG_ARCH_OMAP2PLUS_TYPICAL=n
+CONFIG_ARCH_RENESAS=n
+CONFIG_ARCH_TEGRA=n
+CONFIG_ARCH_VEXPRESS=n
diff --git a/kernel/configs/rust.config b/kernel/configs/rust.config
new file mode 100644
index 000000000..38a7c5362
--- /dev/null
+++ b/kernel/configs/rust.config
@@ -0,0 +1 @@
+CONFIG_RUST=y
diff --git a/kernel/configs/tiny-base.config b/kernel/configs/tiny-base.config
new file mode 100644
index 000000000..2f0e6bf6d
--- /dev/null
+++ b/kernel/configs/tiny-base.config
@@ -0,0 +1 @@
+CONFIG_EMBEDDED=y
diff --git a/kernel/configs/tiny.config b/kernel/configs/tiny.config
new file mode 100644
index 000000000..8a44b93da
--- /dev/null
+++ b/kernel/configs/tiny.config
@@ -0,0 +1,11 @@
+# CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE is not set
+CONFIG_CC_OPTIMIZE_FOR_SIZE=y
+# CONFIG_KERNEL_GZIP is not set
+# CONFIG_KERNEL_BZIP2 is not set
+# CONFIG_KERNEL_LZMA is not set
+CONFIG_KERNEL_XZ=y
+# CONFIG_KERNEL_LZO is not set
+# CONFIG_KERNEL_LZ4 is not set
+# CONFIG_SLAB is not set
+# CONFIG_SLUB is not set
+CONFIG_SLOB=y
diff --git a/kernel/configs/x86_debug.config b/kernel/configs/x86_debug.config
new file mode 100644
index 000000000..6fac5b405
--- /dev/null
+++ b/kernel/configs/x86_debug.config
@@ -0,0 +1,17 @@
+CONFIG_X86_DEBUG_FPU=y
+CONFIG_LOCK_STAT=y
+CONFIG_DEBUG_VM=y
+CONFIG_DEBUG_VM_VMACACHE=y
+CONFIG_DEBUG_VM_RB=y
+CONFIG_DEBUG_SLAB=y
+CONFIG_DEBUG_KMEMLEAK=y
+CONFIG_DEBUG_PAGEALLOC=y
+CONFIG_SLUB_DEBUG_ON=y
+CONFIG_DEBUG_OBJECTS=y
+CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT=1
+CONFIG_GCOV_KERNEL=y
+CONFIG_LOCKDEP=y
+CONFIG_PROVE_LOCKING=y
+CONFIG_SCHEDSTATS=y
+CONFIG_NOINSTR_VALIDATION=y
+CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
diff --git a/kernel/configs/xen.config b/kernel/configs/xen.config
new file mode 100644
index 000000000..436f806aa
--- /dev/null
+++ b/kernel/configs/xen.config
@@ -0,0 +1,47 @@
+# global stuff - these enable us to allow some
+# of the not so generic stuff below for xen
+CONFIG_PARAVIRT=y
+CONFIG_NET=y
+CONFIG_NET_CORE=y
+CONFIG_NETDEVICES=y
+CONFIG_BLOCK=y
+CONFIG_WATCHDOG=y
+CONFIG_TARGET_CORE=y
+CONFIG_SCSI=y
+CONFIG_FB=y
+CONFIG_INPUT_MISC=y
+CONFIG_MEMORY_HOTPLUG=y
+CONFIG_TTY=y
+# Technically not required but otherwise produces
+# pretty useless systems starting from allnoconfig
+# You want TCP/IP and ELF binaries right?
+CONFIG_INET=y
+CONFIG_BINFMT_ELF=y
+# generic config
+CONFIG_XEN=y
+CONFIG_XEN_DOM0=y
+# backend drivers
+CONFIG_XEN_BACKEND=y
+CONFIG_XEN_BLKDEV_BACKEND=m
+CONFIG_XEN_NETDEV_BACKEND=m
+CONFIG_HVC_XEN=y
+CONFIG_XEN_WDT=m
+CONFIG_XEN_SCSI_BACKEND=m
+# frontend drivers
+CONFIG_XEN_FBDEV_FRONTEND=m
+CONFIG_HVC_XEN_FRONTEND=y
+CONFIG_INPUT_XEN_KBDDEV_FRONTEND=m
+CONFIG_XEN_SCSI_FRONTEND=m
+# others
+CONFIG_XEN_BALLOON=y
+CONFIG_XEN_DEV_EVTCHN=m
+CONFIG_XEN_BLKDEV_FRONTEND=m
+CONFIG_XEN_NETDEV_FRONTEND=m
+CONFIG_XENFS=m
+CONFIG_XEN_COMPAT_XENFS=y
+CONFIG_XEN_SYS_HYPERVISOR=y
+CONFIG_XEN_XENBUS_FRONTEND=y
+CONFIG_XEN_GNTDEV=m
+CONFIG_XEN_GRANT_DEV_ALLOC=m
+CONFIG_SWIOTLB_XEN=y
+CONFIG_XEN_PRIVCMD=m
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
new file mode 100644
index 000000000..a09f1c193
--- /dev/null
+++ b/kernel/context_tracking.c
@@ -0,0 +1,728 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Context tracking: Probe on high level context boundaries such as kernel,
+ * userspace, guest or idle.
+ *
+ * This is used by RCU to remove its dependency on the timer tick while a CPU
+ * runs in idle, userspace or guest mode.
+ *
+ * User/guest tracking started by Frederic Weisbecker:
+ *
+ * Copyright (C) 2012 Red Hat, Inc., Frederic Weisbecker
+ *
+ * Many thanks to Gilad Ben-Yossef, Paul McKenney, Ingo Molnar, Andrew Morton,
+ * Steven Rostedt, Peter Zijlstra for suggestions and improvements.
+ *
+ * RCU extended quiescent state bits imported from kernel/rcu/tree.c
+ * where the relevant authorship may be found.
+ */
+
+#include <linux/context_tracking.h>
+#include <linux/rcupdate.h>
+#include <linux/sched.h>
+#include <linux/hardirq.h>
+#include <linux/export.h>
+#include <linux/kprobes.h>
+#include <trace/events/rcu.h>
+
+
+DEFINE_PER_CPU(struct context_tracking, context_tracking) = {
+#ifdef CONFIG_CONTEXT_TRACKING_IDLE
+	.dynticks_nesting = 1,
+	.dynticks_nmi_nesting = DYNTICK_IRQ_NONIDLE,
+#endif
+	.state = ATOMIC_INIT(RCU_DYNTICKS_IDX),
+};
+EXPORT_SYMBOL_GPL(context_tracking);
+
+#ifdef CONFIG_CONTEXT_TRACKING_IDLE
+#define TPS(x)  tracepoint_string(x)
+
+/* Record the current task on dyntick-idle entry. */
+static __always_inline void rcu_dynticks_task_enter(void)
+{
+#if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL)
+	WRITE_ONCE(current->rcu_tasks_idle_cpu, smp_processor_id());
+#endif /* #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL) */
+}
+
+/* Record no current task on dyntick-idle exit. */
+static __always_inline void rcu_dynticks_task_exit(void)
+{
+#if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL)
+	WRITE_ONCE(current->rcu_tasks_idle_cpu, -1);
+#endif /* #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL) */
+}
+
+/* Turn on heavyweight RCU tasks trace readers on idle/user entry. */
+static __always_inline void rcu_dynticks_task_trace_enter(void)
+{
+#ifdef CONFIG_TASKS_TRACE_RCU
+	if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB))
+		current->trc_reader_special.b.need_mb = true;
+#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
+}
+
+/* Turn off heavyweight RCU tasks trace readers on idle/user exit. */
+static __always_inline void rcu_dynticks_task_trace_exit(void)
+{
+#ifdef CONFIG_TASKS_TRACE_RCU
+	if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB))
+		current->trc_reader_special.b.need_mb = false;
+#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
+}
+
+/*
+ * Record entry into an extended quiescent state.  This is only to be
+ * called when not already in an extended quiescent state, that is,
+ * RCU is watching prior to the call to this function and is no longer
+ * watching upon return.
+ */
+static noinstr void ct_kernel_exit_state(int offset)
+{
+	int seq;
+
+	/*
+	 * CPUs seeing atomic_add_return() must see prior RCU read-side
+	 * critical sections, and we also must force ordering with the
+	 * next idle sojourn.
+	 */
+	rcu_dynticks_task_trace_enter();  // Before ->dynticks update!
+	seq = ct_state_inc(offset);
+	// RCU is no longer watching.  Better be in extended quiescent state!
+	WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && (seq & RCU_DYNTICKS_IDX));
+}
+
+/*
+ * Record exit from an extended quiescent state.  This is only to be
+ * called from an extended quiescent state, that is, RCU is not watching
+ * prior to the call to this function and is watching upon return.
+ */
+static noinstr void ct_kernel_enter_state(int offset)
+{
+	int seq;
+
+	/*
+	 * CPUs seeing atomic_add_return() must see prior idle sojourns,
+	 * and we also must force ordering with the next RCU read-side
+	 * critical section.
+	 */
+	seq = ct_state_inc(offset);
+	// RCU is now watching.  Better not be in an extended quiescent state!
+	rcu_dynticks_task_trace_exit();  // After ->dynticks update!
+	WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !(seq & RCU_DYNTICKS_IDX));
+}
+
+/*
+ * Enter an RCU extended quiescent state, which can be either the
+ * idle loop or adaptive-tickless usermode execution.
+ *
+ * We crowbar the ->dynticks_nmi_nesting field to zero to allow for
+ * the possibility of usermode upcalls having messed up our count
+ * of interrupt nesting level during the prior busy period.
+ */
+static void noinstr ct_kernel_exit(bool user, int offset)
+{
+	struct context_tracking *ct = this_cpu_ptr(&context_tracking);
+
+	WARN_ON_ONCE(ct_dynticks_nmi_nesting() != DYNTICK_IRQ_NONIDLE);
+	WRITE_ONCE(ct->dynticks_nmi_nesting, 0);
+	WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) &&
+		     ct_dynticks_nesting() == 0);
+	if (ct_dynticks_nesting() != 1) {
+		// RCU will still be watching, so just do accounting and leave.
+		ct->dynticks_nesting--;
+		return;
+	}
+
+	instrumentation_begin();
+	lockdep_assert_irqs_disabled();
+	trace_rcu_dyntick(TPS("Start"), ct_dynticks_nesting(), 0, ct_dynticks());
+	WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current));
+	rcu_preempt_deferred_qs(current);
+
+	// instrumentation for the noinstr ct_kernel_exit_state()
+	instrument_atomic_write(&ct->state, sizeof(ct->state));
+
+	instrumentation_end();
+	WRITE_ONCE(ct->dynticks_nesting, 0); /* Avoid irq-access tearing. */
+	// RCU is watching here ...
+	ct_kernel_exit_state(offset);
+	// ... but is no longer watching here.
+	rcu_dynticks_task_enter();
+}
+
+/*
+ * Exit an RCU extended quiescent state, which can be either the
+ * idle loop or adaptive-tickless usermode execution.
+ *
+ * We crowbar the ->dynticks_nmi_nesting field to DYNTICK_IRQ_NONIDLE to
+ * allow for the possibility of usermode upcalls messing up our count of
+ * interrupt nesting level during the busy period that is just now starting.
+ */
+static void noinstr ct_kernel_enter(bool user, int offset)
+{
+	struct context_tracking *ct = this_cpu_ptr(&context_tracking);
+	long oldval;
+
+	WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !raw_irqs_disabled());
+	oldval = ct_dynticks_nesting();
+	WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && oldval < 0);
+	if (oldval) {
+		// RCU was already watching, so just do accounting and leave.
+		ct->dynticks_nesting++;
+		return;
+	}
+	rcu_dynticks_task_exit();
+	// RCU is not watching here ...
+	ct_kernel_enter_state(offset);
+	// ... but is watching here.
+	instrumentation_begin();
+
+	// instrumentation for the noinstr ct_kernel_enter_state()
+	instrument_atomic_write(&ct->state, sizeof(ct->state));
+
+	trace_rcu_dyntick(TPS("End"), ct_dynticks_nesting(), 1, ct_dynticks());
+	WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current));
+	WRITE_ONCE(ct->dynticks_nesting, 1);
+	WARN_ON_ONCE(ct_dynticks_nmi_nesting());
+	WRITE_ONCE(ct->dynticks_nmi_nesting, DYNTICK_IRQ_NONIDLE);
+	instrumentation_end();
+}
+
+/**
+ * ct_nmi_exit - inform RCU of exit from NMI context
+ *
+ * If we are returning from the outermost NMI handler that interrupted an
+ * RCU-idle period, update ct->state and ct->dynticks_nmi_nesting
+ * to let the RCU grace-period handling know that the CPU is back to
+ * being RCU-idle.
+ *
+ * If you add or remove a call to ct_nmi_exit(), be sure to test
+ * with CONFIG_RCU_EQS_DEBUG=y.
+ */
+void noinstr ct_nmi_exit(void)
+{
+	struct context_tracking *ct = this_cpu_ptr(&context_tracking);
+
+	instrumentation_begin();
+	/*
+	 * Check for ->dynticks_nmi_nesting underflow and bad ->dynticks.
+	 * (We are exiting an NMI handler, so RCU better be paying attention
+	 * to us!)
+	 */
+	WARN_ON_ONCE(ct_dynticks_nmi_nesting() <= 0);
+	WARN_ON_ONCE(rcu_dynticks_curr_cpu_in_eqs());
+
+	/*
+	 * If the nesting level is not 1, the CPU wasn't RCU-idle, so
+	 * leave it in non-RCU-idle state.
+	 */
+	if (ct_dynticks_nmi_nesting() != 1) {
+		trace_rcu_dyntick(TPS("--="), ct_dynticks_nmi_nesting(), ct_dynticks_nmi_nesting() - 2,
+				  ct_dynticks());
+		WRITE_ONCE(ct->dynticks_nmi_nesting, /* No store tearing. */
+			   ct_dynticks_nmi_nesting() - 2);
+		instrumentation_end();
+		return;
+	}
+
+	/* This NMI interrupted an RCU-idle CPU, restore RCU-idleness. */
+	trace_rcu_dyntick(TPS("Startirq"), ct_dynticks_nmi_nesting(), 0, ct_dynticks());
+	WRITE_ONCE(ct->dynticks_nmi_nesting, 0); /* Avoid store tearing. */
+
+	// instrumentation for the noinstr ct_kernel_exit_state()
+	instrument_atomic_write(&ct->state, sizeof(ct->state));
+	instrumentation_end();
+
+	// RCU is watching here ...
+	ct_kernel_exit_state(RCU_DYNTICKS_IDX);
+	// ... but is no longer watching here.
+
+	if (!in_nmi())
+		rcu_dynticks_task_enter();
+}
+
+/**
+ * ct_nmi_enter - inform RCU of entry to NMI context
+ *
+ * If the CPU was idle from RCU's viewpoint, update ct->state and
+ * ct->dynticks_nmi_nesting to let the RCU grace-period handling know
+ * that the CPU is active.  This implementation permits nested NMIs, as
+ * long as the nesting level does not overflow an int.  (You will probably
+ * run out of stack space first.)
+ *
+ * If you add or remove a call to ct_nmi_enter(), be sure to test
+ * with CONFIG_RCU_EQS_DEBUG=y.
+ */
+void noinstr ct_nmi_enter(void)
+{
+	long incby = 2;
+	struct context_tracking *ct = this_cpu_ptr(&context_tracking);
+
+	/* Complain about underflow. */
+	WARN_ON_ONCE(ct_dynticks_nmi_nesting() < 0);
+
+	/*
+	 * If idle from RCU viewpoint, atomically increment ->dynticks
+	 * to mark non-idle and increment ->dynticks_nmi_nesting by one.
+	 * Otherwise, increment ->dynticks_nmi_nesting by two.  This means
+	 * if ->dynticks_nmi_nesting is equal to one, we are guaranteed
+	 * to be in the outermost NMI handler that interrupted an RCU-idle
+	 * period (observation due to Andy Lutomirski).
+	 */
+	if (rcu_dynticks_curr_cpu_in_eqs()) {
+
+		if (!in_nmi())
+			rcu_dynticks_task_exit();
+
+		// RCU is not watching here ...
+		ct_kernel_enter_state(RCU_DYNTICKS_IDX);
+		// ... but is watching here.
+
+		instrumentation_begin();
+		// instrumentation for the noinstr rcu_dynticks_curr_cpu_in_eqs()
+		instrument_atomic_read(&ct->state, sizeof(ct->state));
+		// instrumentation for the noinstr ct_kernel_enter_state()
+		instrument_atomic_write(&ct->state, sizeof(ct->state));
+
+		incby = 1;
+	} else if (!in_nmi()) {
+		instrumentation_begin();
+		rcu_irq_enter_check_tick();
+	} else  {
+		instrumentation_begin();
+	}
+
+	trace_rcu_dyntick(incby == 1 ? TPS("Endirq") : TPS("++="),
+			  ct_dynticks_nmi_nesting(),
+			  ct_dynticks_nmi_nesting() + incby, ct_dynticks());
+	instrumentation_end();
+	WRITE_ONCE(ct->dynticks_nmi_nesting, /* Prevent store tearing. */
+		   ct_dynticks_nmi_nesting() + incby);
+	barrier();
+}
+
+/**
+ * ct_idle_enter - inform RCU that current CPU is entering idle
+ *
+ * Enter idle mode, in other words, -leave- the mode in which RCU
+ * read-side critical sections can occur.  (Though RCU read-side
+ * critical sections can occur in irq handlers in idle, a possibility
+ * handled by irq_enter() and irq_exit().)
+ *
+ * If you add or remove a call to ct_idle_enter(), be sure to test with
+ * CONFIG_RCU_EQS_DEBUG=y.
+ */
+void noinstr ct_idle_enter(void)
+{
+	WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !raw_irqs_disabled());
+	ct_kernel_exit(false, RCU_DYNTICKS_IDX + CONTEXT_IDLE);
+}
+EXPORT_SYMBOL_GPL(ct_idle_enter);
+
+/**
+ * ct_idle_exit - inform RCU that current CPU is leaving idle
+ *
+ * Exit idle mode, in other words, -enter- the mode in which RCU
+ * read-side critical sections can occur.
+ *
+ * If you add or remove a call to ct_idle_exit(), be sure to test with
+ * CONFIG_RCU_EQS_DEBUG=y.
+ */
+void noinstr ct_idle_exit(void)
+{
+	unsigned long flags;
+
+	raw_local_irq_save(flags);
+	ct_kernel_enter(false, RCU_DYNTICKS_IDX - CONTEXT_IDLE);
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(ct_idle_exit);
+
+/**
+ * ct_irq_enter - inform RCU that current CPU is entering irq away from idle
+ *
+ * Enter an interrupt handler, which might possibly result in exiting
+ * idle mode, in other words, entering the mode in which read-side critical
+ * sections can occur.  The caller must have disabled interrupts.
+ *
+ * Note that the Linux kernel is fully capable of entering an interrupt
+ * handler that it never exits, for example when doing upcalls to user mode!
+ * This code assumes that the idle loop never does upcalls to user mode.
+ * If your architecture's idle loop does do upcalls to user mode (or does
+ * anything else that results in unbalanced calls to the irq_enter() and
+ * irq_exit() functions), RCU will give you what you deserve, good and hard.
+ * But very infrequently and irreproducibly.
+ *
+ * Use things like work queues to work around this limitation.
+ *
+ * You have been warned.
+ *
+ * If you add or remove a call to ct_irq_enter(), be sure to test with
+ * CONFIG_RCU_EQS_DEBUG=y.
+ */
+noinstr void ct_irq_enter(void)
+{
+	lockdep_assert_irqs_disabled();
+	ct_nmi_enter();
+}
+
+/**
+ * ct_irq_exit - inform RCU that current CPU is exiting irq towards idle
+ *
+ * Exit from an interrupt handler, which might possibly result in entering
+ * idle mode, in other words, leaving the mode in which read-side critical
+ * sections can occur.  The caller must have disabled interrupts.
+ *
+ * This code assumes that the idle loop never does anything that might
+ * result in unbalanced calls to irq_enter() and irq_exit().  If your
+ * architecture's idle loop violates this assumption, RCU will give you what
+ * you deserve, good and hard.  But very infrequently and irreproducibly.
+ *
+ * Use things like work queues to work around this limitation.
+ *
+ * You have been warned.
+ *
+ * If you add or remove a call to ct_irq_exit(), be sure to test with
+ * CONFIG_RCU_EQS_DEBUG=y.
+ */
+noinstr void ct_irq_exit(void)
+{
+	lockdep_assert_irqs_disabled();
+	ct_nmi_exit();
+}
+
+/*
+ * Wrapper for ct_irq_enter() where interrupts are enabled.
+ *
+ * If you add or remove a call to ct_irq_enter_irqson(), be sure to test
+ * with CONFIG_RCU_EQS_DEBUG=y.
+ */
+void ct_irq_enter_irqson(void)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	ct_irq_enter();
+	local_irq_restore(flags);
+}
+
+/*
+ * Wrapper for ct_irq_exit() where interrupts are enabled.
+ *
+ * If you add or remove a call to ct_irq_exit_irqson(), be sure to test
+ * with CONFIG_RCU_EQS_DEBUG=y.
+ */
+void ct_irq_exit_irqson(void)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	ct_irq_exit();
+	local_irq_restore(flags);
+}
+#else
+static __always_inline void ct_kernel_exit(bool user, int offset) { }
+static __always_inline void ct_kernel_enter(bool user, int offset) { }
+#endif /* #ifdef CONFIG_CONTEXT_TRACKING_IDLE */
+
+#ifdef CONFIG_CONTEXT_TRACKING_USER
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/context_tracking.h>
+
+DEFINE_STATIC_KEY_FALSE(context_tracking_key);
+EXPORT_SYMBOL_GPL(context_tracking_key);
+
+static noinstr bool context_tracking_recursion_enter(void)
+{
+	int recursion;
+
+	recursion = __this_cpu_inc_return(context_tracking.recursion);
+	if (recursion == 1)
+		return true;
+
+	WARN_ONCE((recursion < 1), "Invalid context tracking recursion value %d\n", recursion);
+	__this_cpu_dec(context_tracking.recursion);
+
+	return false;
+}
+
+static __always_inline void context_tracking_recursion_exit(void)
+{
+	__this_cpu_dec(context_tracking.recursion);
+}
+
+/**
+ * __ct_user_enter - Inform the context tracking that the CPU is going
+ *		     to enter user or guest space mode.
+ *
+ * This function must be called right before we switch from the kernel
+ * to user or guest space, when it's guaranteed the remaining kernel
+ * instructions to execute won't use any RCU read side critical section
+ * because this function sets RCU in extended quiescent state.
+ */
+void noinstr __ct_user_enter(enum ctx_state state)
+{
+	struct context_tracking *ct = this_cpu_ptr(&context_tracking);
+	lockdep_assert_irqs_disabled();
+
+	/* Kernel threads aren't supposed to go to userspace */
+	WARN_ON_ONCE(!current->mm);
+
+	if (!context_tracking_recursion_enter())
+		return;
+
+	if (__ct_state() != state) {
+		if (ct->active) {
+			/*
+			 * At this stage, only low level arch entry code remains and
+			 * then we'll run in userspace. We can assume there won't be
+			 * any RCU read-side critical section until the next call to
+			 * user_exit() or ct_irq_enter(). Let's remove RCU's dependency
+			 * on the tick.
+			 */
+			if (state == CONTEXT_USER) {
+				instrumentation_begin();
+				trace_user_enter(0);
+				vtime_user_enter(current);
+				instrumentation_end();
+			}
+			/*
+			 * Other than generic entry implementation, we may be past the last
+			 * rescheduling opportunity in the entry code. Trigger a self IPI
+			 * that will fire and reschedule once we resume in user/guest mode.
+			 */
+			rcu_irq_work_resched();
+
+			/*
+			 * Enter RCU idle mode right before resuming userspace.  No use of RCU
+			 * is permitted between this call and rcu_eqs_exit(). This way the
+			 * CPU doesn't need to maintain the tick for RCU maintenance purposes
+			 * when the CPU runs in userspace.
+			 */
+			ct_kernel_exit(true, RCU_DYNTICKS_IDX + state);
+
+			/*
+			 * Special case if we only track user <-> kernel transitions for tickless
+			 * cputime accounting but we don't support RCU extended quiescent state.
+			 * In this we case we don't care about any concurrency/ordering.
+			 */
+			if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE))
+				arch_atomic_set(&ct->state, state);
+		} else {
+			/*
+			 * Even if context tracking is disabled on this CPU, because it's outside
+			 * the full dynticks mask for example, we still have to keep track of the
+			 * context transitions and states to prevent inconsistency on those of
+			 * other CPUs.
+			 * If a task triggers an exception in userspace, sleep on the exception
+			 * handler and then migrate to another CPU, that new CPU must know where
+			 * the exception returns by the time we call exception_exit().
+			 * This information can only be provided by the previous CPU when it called
+			 * exception_enter().
+			 * OTOH we can spare the calls to vtime and RCU when context_tracking.active
+			 * is false because we know that CPU is not tickless.
+			 */
+			if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) {
+				/* Tracking for vtime only, no concurrent RCU EQS accounting */
+				arch_atomic_set(&ct->state, state);
+			} else {
+				/*
+				 * Tracking for vtime and RCU EQS. Make sure we don't race
+				 * with NMIs. OTOH we don't care about ordering here since
+				 * RCU only requires RCU_DYNTICKS_IDX increments to be fully
+				 * ordered.
+				 */
+				arch_atomic_add(state, &ct->state);
+			}
+		}
+	}
+	context_tracking_recursion_exit();
+}
+EXPORT_SYMBOL_GPL(__ct_user_enter);
+
+/*
+ * OBSOLETE:
+ * This function should be noinstr but the below local_irq_restore() is
+ * unsafe because it involves illegal RCU uses through tracing and lockdep.
+ * This is unlikely to be fixed as this function is obsolete. The preferred
+ * way is to call __context_tracking_enter() through user_enter_irqoff()
+ * or context_tracking_guest_enter(). It should be the arch entry code
+ * responsibility to call into context tracking with IRQs disabled.
+ */
+void ct_user_enter(enum ctx_state state)
+{
+	unsigned long flags;
+
+	/*
+	 * Some contexts may involve an exception occuring in an irq,
+	 * leading to that nesting:
+	 * ct_irq_enter() rcu_eqs_exit(true) rcu_eqs_enter(true) ct_irq_exit()
+	 * This would mess up the dyntick_nesting count though. And rcu_irq_*()
+	 * helpers are enough to protect RCU uses inside the exception. So
+	 * just return immediately if we detect we are in an IRQ.
+	 */
+	if (in_interrupt())
+		return;
+
+	local_irq_save(flags);
+	__ct_user_enter(state);
+	local_irq_restore(flags);
+}
+NOKPROBE_SYMBOL(ct_user_enter);
+EXPORT_SYMBOL_GPL(ct_user_enter);
+
+/**
+ * user_enter_callable() - Unfortunate ASM callable version of user_enter() for
+ *			   archs that didn't manage to check the context tracking
+ *			   static key from low level code.
+ *
+ * This OBSOLETE function should be noinstr but it unsafely calls
+ * local_irq_restore(), involving illegal RCU uses through tracing and lockdep.
+ * This is unlikely to be fixed as this function is obsolete. The preferred
+ * way is to call user_enter_irqoff(). It should be the arch entry code
+ * responsibility to call into context tracking with IRQs disabled.
+ */
+void user_enter_callable(void)
+{
+	user_enter();
+}
+NOKPROBE_SYMBOL(user_enter_callable);
+
+/**
+ * __ct_user_exit - Inform the context tracking that the CPU is
+ *		    exiting user or guest mode and entering the kernel.
+ *
+ * This function must be called after we entered the kernel from user or
+ * guest space before any use of RCU read side critical section. This
+ * potentially include any high level kernel code like syscalls, exceptions,
+ * signal handling, etc...
+ *
+ * This call supports re-entrancy. This way it can be called from any exception
+ * handler without needing to know if we came from userspace or not.
+ */
+void noinstr __ct_user_exit(enum ctx_state state)
+{
+	struct context_tracking *ct = this_cpu_ptr(&context_tracking);
+
+	if (!context_tracking_recursion_enter())
+		return;
+
+	if (__ct_state() == state) {
+		if (ct->active) {
+			/*
+			 * Exit RCU idle mode while entering the kernel because it can
+			 * run a RCU read side critical section anytime.
+			 */
+			ct_kernel_enter(true, RCU_DYNTICKS_IDX - state);
+			if (state == CONTEXT_USER) {
+				instrumentation_begin();
+				vtime_user_exit(current);
+				trace_user_exit(0);
+				instrumentation_end();
+			}
+
+			/*
+			 * Special case if we only track user <-> kernel transitions for tickless
+			 * cputime accounting but we don't support RCU extended quiescent state.
+			 * In this we case we don't care about any concurrency/ordering.
+			 */
+			if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE))
+				arch_atomic_set(&ct->state, CONTEXT_KERNEL);
+
+		} else {
+			if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) {
+				/* Tracking for vtime only, no concurrent RCU EQS accounting */
+				arch_atomic_set(&ct->state, CONTEXT_KERNEL);
+			} else {
+				/*
+				 * Tracking for vtime and RCU EQS. Make sure we don't race
+				 * with NMIs. OTOH we don't care about ordering here since
+				 * RCU only requires RCU_DYNTICKS_IDX increments to be fully
+				 * ordered.
+				 */
+				arch_atomic_sub(state, &ct->state);
+			}
+		}
+	}
+	context_tracking_recursion_exit();
+}
+EXPORT_SYMBOL_GPL(__ct_user_exit);
+
+/*
+ * OBSOLETE:
+ * This function should be noinstr but the below local_irq_save() is
+ * unsafe because it involves illegal RCU uses through tracing and lockdep.
+ * This is unlikely to be fixed as this function is obsolete. The preferred
+ * way is to call __context_tracking_exit() through user_exit_irqoff()
+ * or context_tracking_guest_exit(). It should be the arch entry code
+ * responsibility to call into context tracking with IRQs disabled.
+ */
+void ct_user_exit(enum ctx_state state)
+{
+	unsigned long flags;
+
+	if (in_interrupt())
+		return;
+
+	local_irq_save(flags);
+	__ct_user_exit(state);
+	local_irq_restore(flags);
+}
+NOKPROBE_SYMBOL(ct_user_exit);
+EXPORT_SYMBOL_GPL(ct_user_exit);
+
+/**
+ * user_exit_callable() - Unfortunate ASM callable version of user_exit() for
+ *			  archs that didn't manage to check the context tracking
+ *			  static key from low level code.
+ *
+ * This OBSOLETE function should be noinstr but it unsafely calls local_irq_save(),
+ * involving illegal RCU uses through tracing and lockdep. This is unlikely
+ * to be fixed as this function is obsolete. The preferred way is to call
+ * user_exit_irqoff(). It should be the arch entry code responsibility to
+ * call into context tracking with IRQs disabled.
+ */
+void user_exit_callable(void)
+{
+	user_exit();
+}
+NOKPROBE_SYMBOL(user_exit_callable);
+
+void __init ct_cpu_track_user(int cpu)
+{
+	static __initdata bool initialized = false;
+
+	if (!per_cpu(context_tracking.active, cpu)) {
+		per_cpu(context_tracking.active, cpu) = true;
+		static_branch_inc(&context_tracking_key);
+	}
+
+	if (initialized)
+		return;
+
+#ifdef CONFIG_HAVE_TIF_NOHZ
+	/*
+	 * Set TIF_NOHZ to init/0 and let it propagate to all tasks through fork
+	 * This assumes that init is the only task at this early boot stage.
+	 */
+	set_tsk_thread_flag(&init_task, TIF_NOHZ);
+#endif
+	WARN_ON_ONCE(!tasklist_empty());
+
+	initialized = true;
+}
+
+#ifdef CONFIG_CONTEXT_TRACKING_USER_FORCE
+void __init context_tracking_init(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		ct_cpu_track_user(cpu);
+}
+#endif
+
+#endif /* #ifdef CONFIG_CONTEXT_TRACKING_USER */
diff --git a/kernel/cpu.c b/kernel/cpu.c
new file mode 100644
index 000000000..e6f010194
--- /dev/null
+++ b/kernel/cpu.c
@@ -0,0 +1,2821 @@
+/* CPU control.
+ * (C) 2001, 2002, 2003, 2004 Rusty Russell
+ *
+ * This code is licenced under the GPL.
+ */
+#include <linux/sched/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/smp.h>
+#include <linux/init.h>
+#include <linux/notifier.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/hotplug.h>
+#include <linux/sched/isolation.h>
+#include <linux/sched/task.h>
+#include <linux/sched/smt.h>
+#include <linux/unistd.h>
+#include <linux/cpu.h>
+#include <linux/oom.h>
+#include <linux/rcupdate.h>
+#include <linux/export.h>
+#include <linux/bug.h>
+#include <linux/kthread.h>
+#include <linux/stop_machine.h>
+#include <linux/mutex.h>
+#include <linux/gfp.h>
+#include <linux/suspend.h>
+#include <linux/lockdep.h>
+#include <linux/tick.h>
+#include <linux/irq.h>
+#include <linux/nmi.h>
+#include <linux/smpboot.h>
+#include <linux/relay.h>
+#include <linux/slab.h>
+#include <linux/scs.h>
+#include <linux/percpu-rwsem.h>
+#include <linux/cpuset.h>
+#include <linux/random.h>
+#include <linux/cc_platform.h>
+
+#include <trace/events/power.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/cpuhp.h>
+
+#include "smpboot.h"
+
+/**
+ * struct cpuhp_cpu_state - Per cpu hotplug state storage
+ * @state:	The current cpu state
+ * @target:	The target state
+ * @fail:	Current CPU hotplug callback state
+ * @thread:	Pointer to the hotplug thread
+ * @should_run:	Thread should execute
+ * @rollback:	Perform a rollback
+ * @single:	Single callback invocation
+ * @bringup:	Single callback bringup or teardown selector
+ * @cpu:	CPU number
+ * @node:	Remote CPU node; for multi-instance, do a
+ *		single entry callback for install/remove
+ * @last:	For multi-instance rollback, remember how far we got
+ * @cb_state:	The state for a single callback (install/uninstall)
+ * @result:	Result of the operation
+ * @done_up:	Signal completion to the issuer of the task for cpu-up
+ * @done_down:	Signal completion to the issuer of the task for cpu-down
+ */
+struct cpuhp_cpu_state {
+	enum cpuhp_state	state;
+	enum cpuhp_state	target;
+	enum cpuhp_state	fail;
+#ifdef CONFIG_SMP
+	struct task_struct	*thread;
+	bool			should_run;
+	bool			rollback;
+	bool			single;
+	bool			bringup;
+	struct hlist_node	*node;
+	struct hlist_node	*last;
+	enum cpuhp_state	cb_state;
+	int			result;
+	struct completion	done_up;
+	struct completion	done_down;
+#endif
+};
+
+static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = {
+	.fail = CPUHP_INVALID,
+};
+
+#ifdef CONFIG_SMP
+cpumask_t cpus_booted_once_mask;
+#endif
+
+#if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP)
+static struct lockdep_map cpuhp_state_up_map =
+	STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map);
+static struct lockdep_map cpuhp_state_down_map =
+	STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map);
+
+
+static inline void cpuhp_lock_acquire(bool bringup)
+{
+	lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map);
+}
+
+static inline void cpuhp_lock_release(bool bringup)
+{
+	lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map);
+}
+#else
+
+static inline void cpuhp_lock_acquire(bool bringup) { }
+static inline void cpuhp_lock_release(bool bringup) { }
+
+#endif
+
+/**
+ * struct cpuhp_step - Hotplug state machine step
+ * @name:	Name of the step
+ * @startup:	Startup function of the step
+ * @teardown:	Teardown function of the step
+ * @cant_stop:	Bringup/teardown can't be stopped at this step
+ * @multi_instance:	State has multiple instances which get added afterwards
+ */
+struct cpuhp_step {
+	const char		*name;
+	union {
+		int		(*single)(unsigned int cpu);
+		int		(*multi)(unsigned int cpu,
+					 struct hlist_node *node);
+	} startup;
+	union {
+		int		(*single)(unsigned int cpu);
+		int		(*multi)(unsigned int cpu,
+					 struct hlist_node *node);
+	} teardown;
+	/* private: */
+	struct hlist_head	list;
+	/* public: */
+	bool			cant_stop;
+	bool			multi_instance;
+};
+
+static DEFINE_MUTEX(cpuhp_state_mutex);
+static struct cpuhp_step cpuhp_hp_states[];
+
+static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state)
+{
+	return cpuhp_hp_states + state;
+}
+
+static bool cpuhp_step_empty(bool bringup, struct cpuhp_step *step)
+{
+	return bringup ? !step->startup.single : !step->teardown.single;
+}
+
+/**
+ * cpuhp_invoke_callback - Invoke the callbacks for a given state
+ * @cpu:	The cpu for which the callback should be invoked
+ * @state:	The state to do callbacks for
+ * @bringup:	True if the bringup callback should be invoked
+ * @node:	For multi-instance, do a single entry callback for install/remove
+ * @lastp:	For multi-instance rollback, remember how far we got
+ *
+ * Called from cpu hotplug and from the state register machinery.
+ *
+ * Return: %0 on success or a negative errno code
+ */
+static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state,
+				 bool bringup, struct hlist_node *node,
+				 struct hlist_node **lastp)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+	struct cpuhp_step *step = cpuhp_get_step(state);
+	int (*cbm)(unsigned int cpu, struct hlist_node *node);
+	int (*cb)(unsigned int cpu);
+	int ret, cnt;
+
+	if (st->fail == state) {
+		st->fail = CPUHP_INVALID;
+		return -EAGAIN;
+	}
+
+	if (cpuhp_step_empty(bringup, step)) {
+		WARN_ON_ONCE(1);
+		return 0;
+	}
+
+	if (!step->multi_instance) {
+		WARN_ON_ONCE(lastp && *lastp);
+		cb = bringup ? step->startup.single : step->teardown.single;
+
+		trace_cpuhp_enter(cpu, st->target, state, cb);
+		ret = cb(cpu);
+		trace_cpuhp_exit(cpu, st->state, state, ret);
+		return ret;
+	}
+	cbm = bringup ? step->startup.multi : step->teardown.multi;
+
+	/* Single invocation for instance add/remove */
+	if (node) {
+		WARN_ON_ONCE(lastp && *lastp);
+		trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
+		ret = cbm(cpu, node);
+		trace_cpuhp_exit(cpu, st->state, state, ret);
+		return ret;
+	}
+
+	/* State transition. Invoke on all instances */
+	cnt = 0;
+	hlist_for_each(node, &step->list) {
+		if (lastp && node == *lastp)
+			break;
+
+		trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
+		ret = cbm(cpu, node);
+		trace_cpuhp_exit(cpu, st->state, state, ret);
+		if (ret) {
+			if (!lastp)
+				goto err;
+
+			*lastp = node;
+			return ret;
+		}
+		cnt++;
+	}
+	if (lastp)
+		*lastp = NULL;
+	return 0;
+err:
+	/* Rollback the instances if one failed */
+	cbm = !bringup ? step->startup.multi : step->teardown.multi;
+	if (!cbm)
+		return ret;
+
+	hlist_for_each(node, &step->list) {
+		if (!cnt--)
+			break;
+
+		trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
+		ret = cbm(cpu, node);
+		trace_cpuhp_exit(cpu, st->state, state, ret);
+		/*
+		 * Rollback must not fail,
+		 */
+		WARN_ON_ONCE(ret);
+	}
+	return ret;
+}
+
+#ifdef CONFIG_SMP
+static bool cpuhp_is_ap_state(enum cpuhp_state state)
+{
+	/*
+	 * The extra check for CPUHP_TEARDOWN_CPU is only for documentation
+	 * purposes as that state is handled explicitly in cpu_down.
+	 */
+	return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU;
+}
+
+static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup)
+{
+	struct completion *done = bringup ? &st->done_up : &st->done_down;
+	wait_for_completion(done);
+}
+
+static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup)
+{
+	struct completion *done = bringup ? &st->done_up : &st->done_down;
+	complete(done);
+}
+
+/*
+ * The former STARTING/DYING states, ran with IRQs disabled and must not fail.
+ */
+static bool cpuhp_is_atomic_state(enum cpuhp_state state)
+{
+	return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE;
+}
+
+/* Serializes the updates to cpu_online_mask, cpu_present_mask */
+static DEFINE_MUTEX(cpu_add_remove_lock);
+bool cpuhp_tasks_frozen;
+EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen);
+
+/*
+ * The following two APIs (cpu_maps_update_begin/done) must be used when
+ * attempting to serialize the updates to cpu_online_mask & cpu_present_mask.
+ */
+void cpu_maps_update_begin(void)
+{
+	mutex_lock(&cpu_add_remove_lock);
+}
+
+void cpu_maps_update_done(void)
+{
+	mutex_unlock(&cpu_add_remove_lock);
+}
+
+/*
+ * If set, cpu_up and cpu_down will return -EBUSY and do nothing.
+ * Should always be manipulated under cpu_add_remove_lock
+ */
+static int cpu_hotplug_disabled;
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock);
+
+void cpus_read_lock(void)
+{
+	percpu_down_read(&cpu_hotplug_lock);
+}
+EXPORT_SYMBOL_GPL(cpus_read_lock);
+
+int cpus_read_trylock(void)
+{
+	return percpu_down_read_trylock(&cpu_hotplug_lock);
+}
+EXPORT_SYMBOL_GPL(cpus_read_trylock);
+
+void cpus_read_unlock(void)
+{
+	percpu_up_read(&cpu_hotplug_lock);
+}
+EXPORT_SYMBOL_GPL(cpus_read_unlock);
+
+void cpus_write_lock(void)
+{
+	percpu_down_write(&cpu_hotplug_lock);
+}
+
+void cpus_write_unlock(void)
+{
+	percpu_up_write(&cpu_hotplug_lock);
+}
+
+void lockdep_assert_cpus_held(void)
+{
+	/*
+	 * We can't have hotplug operations before userspace starts running,
+	 * and some init codepaths will knowingly not take the hotplug lock.
+	 * This is all valid, so mute lockdep until it makes sense to report
+	 * unheld locks.
+	 */
+	if (system_state < SYSTEM_RUNNING)
+		return;
+
+	percpu_rwsem_assert_held(&cpu_hotplug_lock);
+}
+
+#ifdef CONFIG_LOCKDEP
+int lockdep_is_cpus_held(void)
+{
+	return percpu_rwsem_is_held(&cpu_hotplug_lock);
+}
+#endif
+
+static void lockdep_acquire_cpus_lock(void)
+{
+	rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_);
+}
+
+static void lockdep_release_cpus_lock(void)
+{
+	rwsem_release(&cpu_hotplug_lock.dep_map, _THIS_IP_);
+}
+
+/*
+ * Wait for currently running CPU hotplug operations to complete (if any) and
+ * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
+ * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the
+ * hotplug path before performing hotplug operations. So acquiring that lock
+ * guarantees mutual exclusion from any currently running hotplug operations.
+ */
+void cpu_hotplug_disable(void)
+{
+	cpu_maps_update_begin();
+	cpu_hotplug_disabled++;
+	cpu_maps_update_done();
+}
+EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
+
+static void __cpu_hotplug_enable(void)
+{
+	if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n"))
+		return;
+	cpu_hotplug_disabled--;
+}
+
+void cpu_hotplug_enable(void)
+{
+	cpu_maps_update_begin();
+	__cpu_hotplug_enable();
+	cpu_maps_update_done();
+}
+EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
+
+#else
+
+static void lockdep_acquire_cpus_lock(void)
+{
+}
+
+static void lockdep_release_cpus_lock(void)
+{
+}
+
+#endif	/* CONFIG_HOTPLUG_CPU */
+
+/*
+ * Architectures that need SMT-specific errata handling during SMT hotplug
+ * should override this.
+ */
+void __weak arch_smt_update(void) { }
+
+#ifdef CONFIG_HOTPLUG_SMT
+enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED;
+
+void __init cpu_smt_disable(bool force)
+{
+	if (!cpu_smt_possible())
+		return;
+
+	if (force) {
+		pr_info("SMT: Force disabled\n");
+		cpu_smt_control = CPU_SMT_FORCE_DISABLED;
+	} else {
+		pr_info("SMT: disabled\n");
+		cpu_smt_control = CPU_SMT_DISABLED;
+	}
+}
+
+/*
+ * The decision whether SMT is supported can only be done after the full
+ * CPU identification. Called from architecture code.
+ */
+void __init cpu_smt_check_topology(void)
+{
+	if (!topology_smt_supported())
+		cpu_smt_control = CPU_SMT_NOT_SUPPORTED;
+}
+
+static int __init smt_cmdline_disable(char *str)
+{
+	cpu_smt_disable(str && !strcmp(str, "force"));
+	return 0;
+}
+early_param("nosmt", smt_cmdline_disable);
+
+/*
+ * For Archicture supporting partial SMT states check if the thread is allowed.
+ * Otherwise this has already been checked through cpu_smt_max_threads when
+ * setting the SMT level.
+ */
+static inline bool cpu_smt_thread_allowed(unsigned int cpu)
+{
+#ifdef CONFIG_SMT_NUM_THREADS_DYNAMIC
+	return topology_smt_thread_allowed(cpu);
+#else
+	return true;
+#endif
+}
+
+static inline bool cpu_bootable(unsigned int cpu)
+{
+	if (cpu_smt_control == CPU_SMT_ENABLED && cpu_smt_thread_allowed(cpu))
+		return true;
+
+	/* All CPUs are bootable if controls are not configured */
+	if (cpu_smt_control == CPU_SMT_NOT_IMPLEMENTED)
+		return true;
+
+	/* All CPUs are bootable if CPU is not SMT capable */
+	if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED)
+		return true;
+
+	if (topology_is_primary_thread(cpu))
+		return true;
+
+	/*
+	 * On x86 it's required to boot all logical CPUs at least once so
+	 * that the init code can get a chance to set CR4.MCE on each
+	 * CPU. Otherwise, a broadcasted MCE observing CR4.MCE=0b on any
+	 * core will shutdown the machine.
+	 */
+	return !cpumask_test_cpu(cpu, &cpus_booted_once_mask);
+}
+
+/* Returns true if SMT is not supported of forcefully (irreversibly) disabled */
+bool cpu_smt_possible(void)
+{
+	return cpu_smt_control != CPU_SMT_FORCE_DISABLED &&
+		cpu_smt_control != CPU_SMT_NOT_SUPPORTED;
+}
+EXPORT_SYMBOL_GPL(cpu_smt_possible);
+#else
+static inline bool cpu_bootable(unsigned int cpu) { return true; }
+#endif
+
+static inline enum cpuhp_state
+cpuhp_set_state(int cpu, struct cpuhp_cpu_state *st, enum cpuhp_state target)
+{
+	enum cpuhp_state prev_state = st->state;
+	bool bringup = st->state < target;
+
+	st->rollback = false;
+	st->last = NULL;
+
+	st->target = target;
+	st->single = false;
+	st->bringup = bringup;
+	if (cpu_dying(cpu) != !bringup)
+		set_cpu_dying(cpu, !bringup);
+
+	return prev_state;
+}
+
+static inline void
+cpuhp_reset_state(int cpu, struct cpuhp_cpu_state *st,
+		  enum cpuhp_state prev_state)
+{
+	bool bringup = !st->bringup;
+
+	st->target = prev_state;
+
+	/*
+	 * Already rolling back. No need invert the bringup value or to change
+	 * the current state.
+	 */
+	if (st->rollback)
+		return;
+
+	st->rollback = true;
+
+	/*
+	 * If we have st->last we need to undo partial multi_instance of this
+	 * state first. Otherwise start undo at the previous state.
+	 */
+	if (!st->last) {
+		if (st->bringup)
+			st->state--;
+		else
+			st->state++;
+	}
+
+	st->bringup = bringup;
+	if (cpu_dying(cpu) != !bringup)
+		set_cpu_dying(cpu, !bringup);
+}
+
+/* Regular hotplug invocation of the AP hotplug thread */
+static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st)
+{
+	if (!st->single && st->state == st->target)
+		return;
+
+	st->result = 0;
+	/*
+	 * Make sure the above stores are visible before should_run becomes
+	 * true. Paired with the mb() above in cpuhp_thread_fun()
+	 */
+	smp_mb();
+	st->should_run = true;
+	wake_up_process(st->thread);
+	wait_for_ap_thread(st, st->bringup);
+}
+
+static int cpuhp_kick_ap(int cpu, struct cpuhp_cpu_state *st,
+			 enum cpuhp_state target)
+{
+	enum cpuhp_state prev_state;
+	int ret;
+
+	prev_state = cpuhp_set_state(cpu, st, target);
+	__cpuhp_kick_ap(st);
+	if ((ret = st->result)) {
+		cpuhp_reset_state(cpu, st, prev_state);
+		__cpuhp_kick_ap(st);
+	}
+
+	return ret;
+}
+
+static int bringup_wait_for_ap(unsigned int cpu)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+
+	/* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */
+	wait_for_ap_thread(st, true);
+	if (WARN_ON_ONCE((!cpu_online(cpu))))
+		return -ECANCELED;
+
+	/* Unpark the hotplug thread of the target cpu */
+	kthread_unpark(st->thread);
+
+	/*
+	 * SMT soft disabling on X86 requires to bring the CPU out of the
+	 * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit.  The
+	 * CPU marked itself as booted_once in notify_cpu_starting() so the
+	 * cpu_bootable() check will now return false if this is not the
+	 * primary sibling.
+	 */
+	if (!cpu_bootable(cpu))
+		return -ECANCELED;
+
+	if (st->target <= CPUHP_AP_ONLINE_IDLE)
+		return 0;
+
+	return cpuhp_kick_ap(cpu, st, st->target);
+}
+
+static int bringup_cpu(unsigned int cpu)
+{
+	struct task_struct *idle = idle_thread_get(cpu);
+	int ret;
+
+	/*
+	 * Reset stale stack state from the last time this CPU was online.
+	 */
+	scs_task_reset(idle);
+	kasan_unpoison_task_stack(idle);
+
+	/*
+	 * Some architectures have to walk the irq descriptors to
+	 * setup the vector space for the cpu which comes online.
+	 * Prevent irq alloc/free across the bringup.
+	 */
+	irq_lock_sparse();
+
+	/* Arch-specific enabling code. */
+	ret = __cpu_up(cpu, idle);
+	irq_unlock_sparse();
+	if (ret)
+		return ret;
+	return bringup_wait_for_ap(cpu);
+}
+
+static int finish_cpu(unsigned int cpu)
+{
+	struct task_struct *idle = idle_thread_get(cpu);
+	struct mm_struct *mm = idle->active_mm;
+
+	/*
+	 * idle_task_exit() will have switched to &init_mm, now
+	 * clean up any remaining active_mm state.
+	 */
+	if (mm != &init_mm)
+		idle->active_mm = &init_mm;
+	mmdrop(mm);
+	return 0;
+}
+
+/*
+ * Hotplug state machine related functions
+ */
+
+/*
+ * Get the next state to run. Empty ones will be skipped. Returns true if a
+ * state must be run.
+ *
+ * st->state will be modified ahead of time, to match state_to_run, as if it
+ * has already ran.
+ */
+static bool cpuhp_next_state(bool bringup,
+			     enum cpuhp_state *state_to_run,
+			     struct cpuhp_cpu_state *st,
+			     enum cpuhp_state target)
+{
+	do {
+		if (bringup) {
+			if (st->state >= target)
+				return false;
+
+			*state_to_run = ++st->state;
+		} else {
+			if (st->state <= target)
+				return false;
+
+			*state_to_run = st->state--;
+		}
+
+		if (!cpuhp_step_empty(bringup, cpuhp_get_step(*state_to_run)))
+			break;
+	} while (true);
+
+	return true;
+}
+
+static int __cpuhp_invoke_callback_range(bool bringup,
+					 unsigned int cpu,
+					 struct cpuhp_cpu_state *st,
+					 enum cpuhp_state target,
+					 bool nofail)
+{
+	enum cpuhp_state state;
+	int ret = 0;
+
+	while (cpuhp_next_state(bringup, &state, st, target)) {
+		int err;
+
+		err = cpuhp_invoke_callback(cpu, state, bringup, NULL, NULL);
+		if (!err)
+			continue;
+
+		if (nofail) {
+			pr_warn("CPU %u %s state %s (%d) failed (%d)\n",
+				cpu, bringup ? "UP" : "DOWN",
+				cpuhp_get_step(st->state)->name,
+				st->state, err);
+			ret = -1;
+		} else {
+			ret = err;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static inline int cpuhp_invoke_callback_range(bool bringup,
+					      unsigned int cpu,
+					      struct cpuhp_cpu_state *st,
+					      enum cpuhp_state target)
+{
+	return __cpuhp_invoke_callback_range(bringup, cpu, st, target, false);
+}
+
+static inline void cpuhp_invoke_callback_range_nofail(bool bringup,
+						      unsigned int cpu,
+						      struct cpuhp_cpu_state *st,
+						      enum cpuhp_state target)
+{
+	__cpuhp_invoke_callback_range(bringup, cpu, st, target, true);
+}
+
+static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st)
+{
+	if (IS_ENABLED(CONFIG_HOTPLUG_CPU))
+		return true;
+	/*
+	 * When CPU hotplug is disabled, then taking the CPU down is not
+	 * possible because takedown_cpu() and the architecture and
+	 * subsystem specific mechanisms are not available. So the CPU
+	 * which would be completely unplugged again needs to stay around
+	 * in the current state.
+	 */
+	return st->state <= CPUHP_BRINGUP_CPU;
+}
+
+static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
+			      enum cpuhp_state target)
+{
+	enum cpuhp_state prev_state = st->state;
+	int ret = 0;
+
+	ret = cpuhp_invoke_callback_range(true, cpu, st, target);
+	if (ret) {
+		pr_debug("CPU UP failed (%d) CPU %u state %s (%d)\n",
+			 ret, cpu, cpuhp_get_step(st->state)->name,
+			 st->state);
+
+		cpuhp_reset_state(cpu, st, prev_state);
+		if (can_rollback_cpu(st))
+			WARN_ON(cpuhp_invoke_callback_range(false, cpu, st,
+							    prev_state));
+	}
+	return ret;
+}
+
+/*
+ * The cpu hotplug threads manage the bringup and teardown of the cpus
+ */
+static int cpuhp_should_run(unsigned int cpu)
+{
+	struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
+
+	return st->should_run;
+}
+
+/*
+ * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke
+ * callbacks when a state gets [un]installed at runtime.
+ *
+ * Each invocation of this function by the smpboot thread does a single AP
+ * state callback.
+ *
+ * It has 3 modes of operation:
+ *  - single: runs st->cb_state
+ *  - up:     runs ++st->state, while st->state < st->target
+ *  - down:   runs st->state--, while st->state > st->target
+ *
+ * When complete or on error, should_run is cleared and the completion is fired.
+ */
+static void cpuhp_thread_fun(unsigned int cpu)
+{
+	struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
+	bool bringup = st->bringup;
+	enum cpuhp_state state;
+
+	if (WARN_ON_ONCE(!st->should_run))
+		return;
+
+	/*
+	 * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures
+	 * that if we see ->should_run we also see the rest of the state.
+	 */
+	smp_mb();
+
+	/*
+	 * The BP holds the hotplug lock, but we're now running on the AP,
+	 * ensure that anybody asserting the lock is held, will actually find
+	 * it so.
+	 */
+	lockdep_acquire_cpus_lock();
+	cpuhp_lock_acquire(bringup);
+
+	if (st->single) {
+		state = st->cb_state;
+		st->should_run = false;
+	} else {
+		st->should_run = cpuhp_next_state(bringup, &state, st, st->target);
+		if (!st->should_run)
+			goto end;
+	}
+
+	WARN_ON_ONCE(!cpuhp_is_ap_state(state));
+
+	if (cpuhp_is_atomic_state(state)) {
+		local_irq_disable();
+		st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last);
+		local_irq_enable();
+
+		/*
+		 * STARTING/DYING must not fail!
+		 */
+		WARN_ON_ONCE(st->result);
+	} else {
+		st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last);
+	}
+
+	if (st->result) {
+		/*
+		 * If we fail on a rollback, we're up a creek without no
+		 * paddle, no way forward, no way back. We loose, thanks for
+		 * playing.
+		 */
+		WARN_ON_ONCE(st->rollback);
+		st->should_run = false;
+	}
+
+end:
+	cpuhp_lock_release(bringup);
+	lockdep_release_cpus_lock();
+
+	if (!st->should_run)
+		complete_ap_thread(st, bringup);
+}
+
+/* Invoke a single callback on a remote cpu */
+static int
+cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup,
+			 struct hlist_node *node)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+	int ret;
+
+	if (!cpu_online(cpu))
+		return 0;
+
+	cpuhp_lock_acquire(false);
+	cpuhp_lock_release(false);
+
+	cpuhp_lock_acquire(true);
+	cpuhp_lock_release(true);
+
+	/*
+	 * If we are up and running, use the hotplug thread. For early calls
+	 * we invoke the thread function directly.
+	 */
+	if (!st->thread)
+		return cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
+
+	st->rollback = false;
+	st->last = NULL;
+
+	st->node = node;
+	st->bringup = bringup;
+	st->cb_state = state;
+	st->single = true;
+
+	__cpuhp_kick_ap(st);
+
+	/*
+	 * If we failed and did a partial, do a rollback.
+	 */
+	if ((ret = st->result) && st->last) {
+		st->rollback = true;
+		st->bringup = !bringup;
+
+		__cpuhp_kick_ap(st);
+	}
+
+	/*
+	 * Clean up the leftovers so the next hotplug operation wont use stale
+	 * data.
+	 */
+	st->node = st->last = NULL;
+	return ret;
+}
+
+static int cpuhp_kick_ap_work(unsigned int cpu)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+	enum cpuhp_state prev_state = st->state;
+	int ret;
+
+	cpuhp_lock_acquire(false);
+	cpuhp_lock_release(false);
+
+	cpuhp_lock_acquire(true);
+	cpuhp_lock_release(true);
+
+	trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work);
+	ret = cpuhp_kick_ap(cpu, st, st->target);
+	trace_cpuhp_exit(cpu, st->state, prev_state, ret);
+
+	return ret;
+}
+
+static struct smp_hotplug_thread cpuhp_threads = {
+	.store			= &cpuhp_state.thread,
+	.thread_should_run	= cpuhp_should_run,
+	.thread_fn		= cpuhp_thread_fun,
+	.thread_comm		= "cpuhp/%u",
+	.selfparking		= true,
+};
+
+static __init void cpuhp_init_state(void)
+{
+	struct cpuhp_cpu_state *st;
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		st = per_cpu_ptr(&cpuhp_state, cpu);
+		init_completion(&st->done_up);
+		init_completion(&st->done_down);
+	}
+}
+
+void __init cpuhp_threads_init(void)
+{
+	cpuhp_init_state();
+	BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads));
+	kthread_unpark(this_cpu_read(cpuhp_state.thread));
+}
+
+/*
+ *
+ * Serialize hotplug trainwrecks outside of the cpu_hotplug_lock
+ * protected region.
+ *
+ * The operation is still serialized against concurrent CPU hotplug via
+ * cpu_add_remove_lock, i.e. CPU map protection.  But it is _not_
+ * serialized against other hotplug related activity like adding or
+ * removing of state callbacks and state instances, which invoke either the
+ * startup or the teardown callback of the affected state.
+ *
+ * This is required for subsystems which are unfixable vs. CPU hotplug and
+ * evade lock inversion problems by scheduling work which has to be
+ * completed _before_ cpu_up()/_cpu_down() returns.
+ *
+ * Don't even think about adding anything to this for any new code or even
+ * drivers. It's only purpose is to keep existing lock order trainwrecks
+ * working.
+ *
+ * For cpu_down() there might be valid reasons to finish cleanups which are
+ * not required to be done under cpu_hotplug_lock, but that's a different
+ * story and would be not invoked via this.
+ */
+static void cpu_up_down_serialize_trainwrecks(bool tasks_frozen)
+{
+	/*
+	 * cpusets delegate hotplug operations to a worker to "solve" the
+	 * lock order problems. Wait for the worker, but only if tasks are
+	 * _not_ frozen (suspend, hibernate) as that would wait forever.
+	 *
+	 * The wait is required because otherwise the hotplug operation
+	 * returns with inconsistent state, which could even be observed in
+	 * user space when a new CPU is brought up. The CPU plug uevent
+	 * would be delivered and user space reacting on it would fail to
+	 * move tasks to the newly plugged CPU up to the point where the
+	 * work has finished because up to that point the newly plugged CPU
+	 * is not assignable in cpusets/cgroups. On unplug that's not
+	 * necessarily a visible issue, but it is still inconsistent state,
+	 * which is the real problem which needs to be "fixed". This can't
+	 * prevent the transient state between scheduling the work and
+	 * returning from waiting for it.
+	 */
+	if (!tasks_frozen)
+		cpuset_wait_for_hotplug();
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+#ifndef arch_clear_mm_cpumask_cpu
+#define arch_clear_mm_cpumask_cpu(cpu, mm) cpumask_clear_cpu(cpu, mm_cpumask(mm))
+#endif
+
+/**
+ * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
+ * @cpu: a CPU id
+ *
+ * This function walks all processes, finds a valid mm struct for each one and
+ * then clears a corresponding bit in mm's cpumask.  While this all sounds
+ * trivial, there are various non-obvious corner cases, which this function
+ * tries to solve in a safe manner.
+ *
+ * Also note that the function uses a somewhat relaxed locking scheme, so it may
+ * be called only for an already offlined CPU.
+ */
+void clear_tasks_mm_cpumask(int cpu)
+{
+	struct task_struct *p;
+
+	/*
+	 * This function is called after the cpu is taken down and marked
+	 * offline, so its not like new tasks will ever get this cpu set in
+	 * their mm mask. -- Peter Zijlstra
+	 * Thus, we may use rcu_read_lock() here, instead of grabbing
+	 * full-fledged tasklist_lock.
+	 */
+	WARN_ON(cpu_online(cpu));
+	rcu_read_lock();
+	for_each_process(p) {
+		struct task_struct *t;
+
+		/*
+		 * Main thread might exit, but other threads may still have
+		 * a valid mm. Find one.
+		 */
+		t = find_lock_task_mm(p);
+		if (!t)
+			continue;
+		arch_clear_mm_cpumask_cpu(cpu, t->mm);
+		task_unlock(t);
+	}
+	rcu_read_unlock();
+}
+
+/* Take this CPU down. */
+static int take_cpu_down(void *_param)
+{
+	struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
+	enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE);
+	int err, cpu = smp_processor_id();
+
+	/* Ensure this CPU doesn't handle any more interrupts. */
+	err = __cpu_disable();
+	if (err < 0)
+		return err;
+
+	/*
+	 * Must be called from CPUHP_TEARDOWN_CPU, which means, as we are going
+	 * down, that the current state is CPUHP_TEARDOWN_CPU - 1.
+	 */
+	WARN_ON(st->state != (CPUHP_TEARDOWN_CPU - 1));
+
+	/*
+	 * Invoke the former CPU_DYING callbacks. DYING must not fail!
+	 */
+	cpuhp_invoke_callback_range_nofail(false, cpu, st, target);
+
+	/* Give up timekeeping duties */
+	tick_handover_do_timer();
+	/* Remove CPU from timer broadcasting */
+	tick_offline_cpu(cpu);
+	/* Park the stopper thread */
+	stop_machine_park(cpu);
+	return 0;
+}
+
+static int takedown_cpu(unsigned int cpu)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+	int err;
+
+	/* Park the smpboot threads */
+	kthread_park(st->thread);
+
+	/*
+	 * Prevent irq alloc/free while the dying cpu reorganizes the
+	 * interrupt affinities.
+	 */
+	irq_lock_sparse();
+
+	/*
+	 * So now all preempt/rcu users must observe !cpu_active().
+	 */
+	err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu));
+	if (err) {
+		/* CPU refused to die */
+		irq_unlock_sparse();
+		/* Unpark the hotplug thread so we can rollback there */
+		kthread_unpark(st->thread);
+		return err;
+	}
+	BUG_ON(cpu_online(cpu));
+
+	/*
+	 * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed
+	 * all runnable tasks from the CPU, there's only the idle task left now
+	 * that the migration thread is done doing the stop_machine thing.
+	 *
+	 * Wait for the stop thread to go away.
+	 */
+	wait_for_ap_thread(st, false);
+	BUG_ON(st->state != CPUHP_AP_IDLE_DEAD);
+
+	/* Interrupts are moved away from the dying cpu, reenable alloc/free */
+	irq_unlock_sparse();
+
+	hotplug_cpu__broadcast_tick_pull(cpu);
+	/* This actually kills the CPU. */
+	__cpu_die(cpu);
+
+	tick_cleanup_dead_cpu(cpu);
+	rcutree_migrate_callbacks(cpu);
+	return 0;
+}
+
+static void cpuhp_complete_idle_dead(void *arg)
+{
+	struct cpuhp_cpu_state *st = arg;
+
+	complete_ap_thread(st, false);
+}
+
+void cpuhp_report_idle_dead(void)
+{
+	struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
+
+	BUG_ON(st->state != CPUHP_AP_OFFLINE);
+	rcu_report_dead(smp_processor_id());
+	st->state = CPUHP_AP_IDLE_DEAD;
+	/*
+	 * We cannot call complete after rcu_report_dead() so we delegate it
+	 * to an online cpu.
+	 */
+	smp_call_function_single(cpumask_first(cpu_online_mask),
+				 cpuhp_complete_idle_dead, st, 0);
+}
+
+static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
+				enum cpuhp_state target)
+{
+	enum cpuhp_state prev_state = st->state;
+	int ret = 0;
+
+	ret = cpuhp_invoke_callback_range(false, cpu, st, target);
+	if (ret) {
+		pr_debug("CPU DOWN failed (%d) CPU %u state %s (%d)\n",
+			 ret, cpu, cpuhp_get_step(st->state)->name,
+			 st->state);
+
+		cpuhp_reset_state(cpu, st, prev_state);
+
+		if (st->state < prev_state)
+			WARN_ON(cpuhp_invoke_callback_range(true, cpu, st,
+							    prev_state));
+	}
+
+	return ret;
+}
+
+/* Requires cpu_add_remove_lock to be held */
+static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
+			   enum cpuhp_state target)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+	int prev_state, ret = 0;
+
+	if (num_online_cpus() == 1)
+		return -EBUSY;
+
+	if (!cpu_present(cpu))
+		return -EINVAL;
+
+	cpus_write_lock();
+
+	cpuhp_tasks_frozen = tasks_frozen;
+
+	prev_state = cpuhp_set_state(cpu, st, target);
+	/*
+	 * If the current CPU state is in the range of the AP hotplug thread,
+	 * then we need to kick the thread.
+	 */
+	if (st->state > CPUHP_TEARDOWN_CPU) {
+		st->target = max((int)target, CPUHP_TEARDOWN_CPU);
+		ret = cpuhp_kick_ap_work(cpu);
+		/*
+		 * The AP side has done the error rollback already. Just
+		 * return the error code..
+		 */
+		if (ret)
+			goto out;
+
+		/*
+		 * We might have stopped still in the range of the AP hotplug
+		 * thread. Nothing to do anymore.
+		 */
+		if (st->state > CPUHP_TEARDOWN_CPU)
+			goto out;
+
+		st->target = target;
+	}
+	/*
+	 * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need
+	 * to do the further cleanups.
+	 */
+	ret = cpuhp_down_callbacks(cpu, st, target);
+	if (ret && st->state < prev_state) {
+		if (st->state == CPUHP_TEARDOWN_CPU) {
+			cpuhp_reset_state(cpu, st, prev_state);
+			__cpuhp_kick_ap(st);
+		} else {
+			WARN(1, "DEAD callback error for CPU%d", cpu);
+		}
+	}
+
+out:
+	cpus_write_unlock();
+	/*
+	 * Do post unplug cleanup. This is still protected against
+	 * concurrent CPU hotplug via cpu_add_remove_lock.
+	 */
+	lockup_detector_cleanup();
+	arch_smt_update();
+	cpu_up_down_serialize_trainwrecks(tasks_frozen);
+	return ret;
+}
+
+struct cpu_down_work {
+	unsigned int		cpu;
+	enum cpuhp_state	target;
+};
+
+static long __cpu_down_maps_locked(void *arg)
+{
+	struct cpu_down_work *work = arg;
+
+	return _cpu_down(work->cpu, 0, work->target);
+}
+
+static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target)
+{
+	struct cpu_down_work work = { .cpu = cpu, .target = target, };
+
+	/*
+	 * If the platform does not support hotplug, report it explicitly to
+	 * differentiate it from a transient offlining failure.
+	 */
+	if (cc_platform_has(CC_ATTR_HOTPLUG_DISABLED))
+		return -EOPNOTSUPP;
+	if (cpu_hotplug_disabled)
+		return -EBUSY;
+
+	/*
+	 * Ensure that the control task does not run on the to be offlined
+	 * CPU to prevent a deadlock against cfs_b->period_timer.
+	 * Also keep at least one housekeeping cpu onlined to avoid generating
+	 * an empty sched_domain span.
+	 */
+	for_each_cpu_and(cpu, cpu_online_mask, housekeeping_cpumask(HK_TYPE_DOMAIN)) {
+		if (cpu != work.cpu)
+			return work_on_cpu(cpu, __cpu_down_maps_locked, &work);
+	}
+	return -EBUSY;
+}
+
+static int cpu_down(unsigned int cpu, enum cpuhp_state target)
+{
+	int err;
+
+	cpu_maps_update_begin();
+	err = cpu_down_maps_locked(cpu, target);
+	cpu_maps_update_done();
+	return err;
+}
+
+/**
+ * cpu_device_down - Bring down a cpu device
+ * @dev: Pointer to the cpu device to offline
+ *
+ * This function is meant to be used by device core cpu subsystem only.
+ *
+ * Other subsystems should use remove_cpu() instead.
+ *
+ * Return: %0 on success or a negative errno code
+ */
+int cpu_device_down(struct device *dev)
+{
+	return cpu_down(dev->id, CPUHP_OFFLINE);
+}
+
+int remove_cpu(unsigned int cpu)
+{
+	int ret;
+
+	lock_device_hotplug();
+	ret = device_offline(get_cpu_device(cpu));
+	unlock_device_hotplug();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(remove_cpu);
+
+void smp_shutdown_nonboot_cpus(unsigned int primary_cpu)
+{
+	unsigned int cpu;
+	int error;
+
+	cpu_maps_update_begin();
+
+	/*
+	 * Make certain the cpu I'm about to reboot on is online.
+	 *
+	 * This is inline to what migrate_to_reboot_cpu() already do.
+	 */
+	if (!cpu_online(primary_cpu))
+		primary_cpu = cpumask_first(cpu_online_mask);
+
+	for_each_online_cpu(cpu) {
+		if (cpu == primary_cpu)
+			continue;
+
+		error = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
+		if (error) {
+			pr_err("Failed to offline CPU%d - error=%d",
+				cpu, error);
+			break;
+		}
+	}
+
+	/*
+	 * Ensure all but the reboot CPU are offline.
+	 */
+	BUG_ON(num_online_cpus() > 1);
+
+	/*
+	 * Make sure the CPUs won't be enabled by someone else after this
+	 * point. Kexec will reboot to a new kernel shortly resetting
+	 * everything along the way.
+	 */
+	cpu_hotplug_disabled++;
+
+	cpu_maps_update_done();
+}
+
+#else
+#define takedown_cpu		NULL
+#endif /*CONFIG_HOTPLUG_CPU*/
+
+/**
+ * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU
+ * @cpu: cpu that just started
+ *
+ * It must be called by the arch code on the new cpu, before the new cpu
+ * enables interrupts and before the "boot" cpu returns from __cpu_up().
+ */
+void notify_cpu_starting(unsigned int cpu)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+	enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE);
+
+	rcu_cpu_starting(cpu);	/* Enables RCU usage on this CPU. */
+	cpumask_set_cpu(cpu, &cpus_booted_once_mask);
+
+	/*
+	 * STARTING must not fail!
+	 */
+	cpuhp_invoke_callback_range_nofail(true, cpu, st, target);
+}
+
+/*
+ * Called from the idle task. Wake up the controlling task which brings the
+ * hotplug thread of the upcoming CPU up and then delegates the rest of the
+ * online bringup to the hotplug thread.
+ */
+void cpuhp_online_idle(enum cpuhp_state state)
+{
+	struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
+
+	/* Happens for the boot cpu */
+	if (state != CPUHP_AP_ONLINE_IDLE)
+		return;
+
+	/*
+	 * Unpart the stopper thread before we start the idle loop (and start
+	 * scheduling); this ensures the stopper task is always available.
+	 */
+	stop_machine_unpark(smp_processor_id());
+
+	st->state = CPUHP_AP_ONLINE_IDLE;
+	complete_ap_thread(st, true);
+}
+
+/* Requires cpu_add_remove_lock to be held */
+static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+	struct task_struct *idle;
+	int ret = 0;
+
+	cpus_write_lock();
+
+	if (!cpu_present(cpu)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * The caller of cpu_up() might have raced with another
+	 * caller. Nothing to do.
+	 */
+	if (st->state >= target)
+		goto out;
+
+	if (st->state == CPUHP_OFFLINE) {
+		/* Let it fail before we try to bring the cpu up */
+		idle = idle_thread_get(cpu);
+		if (IS_ERR(idle)) {
+			ret = PTR_ERR(idle);
+			goto out;
+		}
+	}
+
+	cpuhp_tasks_frozen = tasks_frozen;
+
+	cpuhp_set_state(cpu, st, target);
+	/*
+	 * If the current CPU state is in the range of the AP hotplug thread,
+	 * then we need to kick the thread once more.
+	 */
+	if (st->state > CPUHP_BRINGUP_CPU) {
+		ret = cpuhp_kick_ap_work(cpu);
+		/*
+		 * The AP side has done the error rollback already. Just
+		 * return the error code..
+		 */
+		if (ret)
+			goto out;
+	}
+
+	/*
+	 * Try to reach the target state. We max out on the BP at
+	 * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is
+	 * responsible for bringing it up to the target state.
+	 */
+	target = min((int)target, CPUHP_BRINGUP_CPU);
+	ret = cpuhp_up_callbacks(cpu, st, target);
+out:
+	cpus_write_unlock();
+	arch_smt_update();
+	cpu_up_down_serialize_trainwrecks(tasks_frozen);
+	return ret;
+}
+
+static int cpu_up(unsigned int cpu, enum cpuhp_state target)
+{
+	int err = 0;
+
+	if (!cpu_possible(cpu)) {
+		pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n",
+		       cpu);
+#if defined(CONFIG_IA64)
+		pr_err("please check additional_cpus= boot parameter\n");
+#endif
+		return -EINVAL;
+	}
+
+	err = try_online_node(cpu_to_node(cpu));
+	if (err)
+		return err;
+
+	cpu_maps_update_begin();
+
+	if (cpu_hotplug_disabled) {
+		err = -EBUSY;
+		goto out;
+	}
+	if (!cpu_bootable(cpu)) {
+		err = -EPERM;
+		goto out;
+	}
+
+	err = _cpu_up(cpu, 0, target);
+out:
+	cpu_maps_update_done();
+	return err;
+}
+
+/**
+ * cpu_device_up - Bring up a cpu device
+ * @dev: Pointer to the cpu device to online
+ *
+ * This function is meant to be used by device core cpu subsystem only.
+ *
+ * Other subsystems should use add_cpu() instead.
+ *
+ * Return: %0 on success or a negative errno code
+ */
+int cpu_device_up(struct device *dev)
+{
+	return cpu_up(dev->id, CPUHP_ONLINE);
+}
+
+int add_cpu(unsigned int cpu)
+{
+	int ret;
+
+	lock_device_hotplug();
+	ret = device_online(get_cpu_device(cpu));
+	unlock_device_hotplug();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(add_cpu);
+
+/**
+ * bringup_hibernate_cpu - Bring up the CPU that we hibernated on
+ * @sleep_cpu: The cpu we hibernated on and should be brought up.
+ *
+ * On some architectures like arm64, we can hibernate on any CPU, but on
+ * wake up the CPU we hibernated on might be offline as a side effect of
+ * using maxcpus= for example.
+ *
+ * Return: %0 on success or a negative errno code
+ */
+int bringup_hibernate_cpu(unsigned int sleep_cpu)
+{
+	int ret;
+
+	if (!cpu_online(sleep_cpu)) {
+		pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n");
+		ret = cpu_up(sleep_cpu, CPUHP_ONLINE);
+		if (ret) {
+			pr_err("Failed to bring hibernate-CPU up!\n");
+			return ret;
+		}
+	}
+	return 0;
+}
+
+void bringup_nonboot_cpus(unsigned int setup_max_cpus)
+{
+	unsigned int cpu;
+
+	for_each_present_cpu(cpu) {
+		if (num_online_cpus() >= setup_max_cpus)
+			break;
+		if (!cpu_online(cpu))
+			cpu_up(cpu, CPUHP_ONLINE);
+	}
+}
+
+#ifdef CONFIG_PM_SLEEP_SMP
+static cpumask_var_t frozen_cpus;
+
+int freeze_secondary_cpus(int primary)
+{
+	int cpu, error = 0;
+
+	cpu_maps_update_begin();
+	if (primary == -1) {
+		primary = cpumask_first(cpu_online_mask);
+		if (!housekeeping_cpu(primary, HK_TYPE_TIMER))
+			primary = housekeeping_any_cpu(HK_TYPE_TIMER);
+	} else {
+		if (!cpu_online(primary))
+			primary = cpumask_first(cpu_online_mask);
+	}
+
+	/*
+	 * We take down all of the non-boot CPUs in one shot to avoid races
+	 * with the userspace trying to use the CPU hotplug at the same time
+	 */
+	cpumask_clear(frozen_cpus);
+
+	pr_info("Disabling non-boot CPUs ...\n");
+	for_each_online_cpu(cpu) {
+		if (cpu == primary)
+			continue;
+
+		if (pm_wakeup_pending()) {
+			pr_info("Wakeup pending. Abort CPU freeze\n");
+			error = -EBUSY;
+			break;
+		}
+
+		trace_suspend_resume(TPS("CPU_OFF"), cpu, true);
+		error = _cpu_down(cpu, 1, CPUHP_OFFLINE);
+		trace_suspend_resume(TPS("CPU_OFF"), cpu, false);
+		if (!error)
+			cpumask_set_cpu(cpu, frozen_cpus);
+		else {
+			pr_err("Error taking CPU%d down: %d\n", cpu, error);
+			break;
+		}
+	}
+
+	if (!error)
+		BUG_ON(num_online_cpus() > 1);
+	else
+		pr_err("Non-boot CPUs are not disabled\n");
+
+	/*
+	 * Make sure the CPUs won't be enabled by someone else. We need to do
+	 * this even in case of failure as all freeze_secondary_cpus() users are
+	 * supposed to do thaw_secondary_cpus() on the failure path.
+	 */
+	cpu_hotplug_disabled++;
+
+	cpu_maps_update_done();
+	return error;
+}
+
+void __weak arch_thaw_secondary_cpus_begin(void)
+{
+}
+
+void __weak arch_thaw_secondary_cpus_end(void)
+{
+}
+
+void thaw_secondary_cpus(void)
+{
+	int cpu, error;
+
+	/* Allow everyone to use the CPU hotplug again */
+	cpu_maps_update_begin();
+	__cpu_hotplug_enable();
+	if (cpumask_empty(frozen_cpus))
+		goto out;
+
+	pr_info("Enabling non-boot CPUs ...\n");
+
+	arch_thaw_secondary_cpus_begin();
+
+	for_each_cpu(cpu, frozen_cpus) {
+		trace_suspend_resume(TPS("CPU_ON"), cpu, true);
+		error = _cpu_up(cpu, 1, CPUHP_ONLINE);
+		trace_suspend_resume(TPS("CPU_ON"), cpu, false);
+		if (!error) {
+			pr_info("CPU%d is up\n", cpu);
+			continue;
+		}
+		pr_warn("Error taking CPU%d up: %d\n", cpu, error);
+	}
+
+	arch_thaw_secondary_cpus_end();
+
+	cpumask_clear(frozen_cpus);
+out:
+	cpu_maps_update_done();
+}
+
+static int __init alloc_frozen_cpus(void)
+{
+	if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO))
+		return -ENOMEM;
+	return 0;
+}
+core_initcall(alloc_frozen_cpus);
+
+/*
+ * When callbacks for CPU hotplug notifications are being executed, we must
+ * ensure that the state of the system with respect to the tasks being frozen
+ * or not, as reported by the notification, remains unchanged *throughout the
+ * duration* of the execution of the callbacks.
+ * Hence we need to prevent the freezer from racing with regular CPU hotplug.
+ *
+ * This synchronization is implemented by mutually excluding regular CPU
+ * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
+ * Hibernate notifications.
+ */
+static int
+cpu_hotplug_pm_callback(struct notifier_block *nb,
+			unsigned long action, void *ptr)
+{
+	switch (action) {
+
+	case PM_SUSPEND_PREPARE:
+	case PM_HIBERNATION_PREPARE:
+		cpu_hotplug_disable();
+		break;
+
+	case PM_POST_SUSPEND:
+	case PM_POST_HIBERNATION:
+		cpu_hotplug_enable();
+		break;
+
+	default:
+		return NOTIFY_DONE;
+	}
+
+	return NOTIFY_OK;
+}
+
+
+static int __init cpu_hotplug_pm_sync_init(void)
+{
+	/*
+	 * cpu_hotplug_pm_callback has higher priority than x86
+	 * bsp_pm_callback which depends on cpu_hotplug_pm_callback
+	 * to disable cpu hotplug to avoid cpu hotplug race.
+	 */
+	pm_notifier(cpu_hotplug_pm_callback, 0);
+	return 0;
+}
+core_initcall(cpu_hotplug_pm_sync_init);
+
+#endif /* CONFIG_PM_SLEEP_SMP */
+
+int __boot_cpu_id;
+
+#endif /* CONFIG_SMP */
+
+/* Boot processor state steps */
+static struct cpuhp_step cpuhp_hp_states[] = {
+	[CPUHP_OFFLINE] = {
+		.name			= "offline",
+		.startup.single		= NULL,
+		.teardown.single	= NULL,
+	},
+#ifdef CONFIG_SMP
+	[CPUHP_CREATE_THREADS]= {
+		.name			= "threads:prepare",
+		.startup.single		= smpboot_create_threads,
+		.teardown.single	= NULL,
+		.cant_stop		= true,
+	},
+	[CPUHP_PERF_PREPARE] = {
+		.name			= "perf:prepare",
+		.startup.single		= perf_event_init_cpu,
+		.teardown.single	= perf_event_exit_cpu,
+	},
+	[CPUHP_RANDOM_PREPARE] = {
+		.name			= "random:prepare",
+		.startup.single		= random_prepare_cpu,
+		.teardown.single	= NULL,
+	},
+	[CPUHP_WORKQUEUE_PREP] = {
+		.name			= "workqueue:prepare",
+		.startup.single		= workqueue_prepare_cpu,
+		.teardown.single	= NULL,
+	},
+	[CPUHP_HRTIMERS_PREPARE] = {
+		.name			= "hrtimers:prepare",
+		.startup.single		= hrtimers_prepare_cpu,
+		.teardown.single	= NULL,
+	},
+	[CPUHP_SMPCFD_PREPARE] = {
+		.name			= "smpcfd:prepare",
+		.startup.single		= smpcfd_prepare_cpu,
+		.teardown.single	= smpcfd_dead_cpu,
+	},
+	[CPUHP_RELAY_PREPARE] = {
+		.name			= "relay:prepare",
+		.startup.single		= relay_prepare_cpu,
+		.teardown.single	= NULL,
+	},
+	[CPUHP_SLAB_PREPARE] = {
+		.name			= "slab:prepare",
+		.startup.single		= slab_prepare_cpu,
+		.teardown.single	= slab_dead_cpu,
+	},
+	[CPUHP_RCUTREE_PREP] = {
+		.name			= "RCU/tree:prepare",
+		.startup.single		= rcutree_prepare_cpu,
+		.teardown.single	= rcutree_dead_cpu,
+	},
+	/*
+	 * On the tear-down path, timers_dead_cpu() must be invoked
+	 * before blk_mq_queue_reinit_notify() from notify_dead(),
+	 * otherwise a RCU stall occurs.
+	 */
+	[CPUHP_TIMERS_PREPARE] = {
+		.name			= "timers:prepare",
+		.startup.single		= timers_prepare_cpu,
+		.teardown.single	= timers_dead_cpu,
+	},
+	/* Kicks the plugged cpu into life */
+	[CPUHP_BRINGUP_CPU] = {
+		.name			= "cpu:bringup",
+		.startup.single		= bringup_cpu,
+		.teardown.single	= finish_cpu,
+		.cant_stop		= true,
+	},
+	/* Final state before CPU kills itself */
+	[CPUHP_AP_IDLE_DEAD] = {
+		.name			= "idle:dead",
+	},
+	/*
+	 * Last state before CPU enters the idle loop to die. Transient state
+	 * for synchronization.
+	 */
+	[CPUHP_AP_OFFLINE] = {
+		.name			= "ap:offline",
+		.cant_stop		= true,
+	},
+	/* First state is scheduler control. Interrupts are disabled */
+	[CPUHP_AP_SCHED_STARTING] = {
+		.name			= "sched:starting",
+		.startup.single		= sched_cpu_starting,
+		.teardown.single	= sched_cpu_dying,
+	},
+	[CPUHP_AP_RCUTREE_DYING] = {
+		.name			= "RCU/tree:dying",
+		.startup.single		= NULL,
+		.teardown.single	= rcutree_dying_cpu,
+	},
+	[CPUHP_AP_SMPCFD_DYING] = {
+		.name			= "smpcfd:dying",
+		.startup.single		= NULL,
+		.teardown.single	= smpcfd_dying_cpu,
+	},
+	[CPUHP_AP_HRTIMERS_DYING] = {
+		.name			= "hrtimers:dying",
+		.startup.single		= NULL,
+		.teardown.single	= hrtimers_cpu_dying,
+	},
+
+	/* Entry state on starting. Interrupts enabled from here on. Transient
+	 * state for synchronsization */
+	[CPUHP_AP_ONLINE] = {
+		.name			= "ap:online",
+	},
+	/*
+	 * Handled on control processor until the plugged processor manages
+	 * this itself.
+	 */
+	[CPUHP_TEARDOWN_CPU] = {
+		.name			= "cpu:teardown",
+		.startup.single		= NULL,
+		.teardown.single	= takedown_cpu,
+		.cant_stop		= true,
+	},
+
+	[CPUHP_AP_SCHED_WAIT_EMPTY] = {
+		.name			= "sched:waitempty",
+		.startup.single		= NULL,
+		.teardown.single	= sched_cpu_wait_empty,
+	},
+
+	/* Handle smpboot threads park/unpark */
+	[CPUHP_AP_SMPBOOT_THREADS] = {
+		.name			= "smpboot/threads:online",
+		.startup.single		= smpboot_unpark_threads,
+		.teardown.single	= smpboot_park_threads,
+	},
+	[CPUHP_AP_IRQ_AFFINITY_ONLINE] = {
+		.name			= "irq/affinity:online",
+		.startup.single		= irq_affinity_online_cpu,
+		.teardown.single	= NULL,
+	},
+	[CPUHP_AP_PERF_ONLINE] = {
+		.name			= "perf:online",
+		.startup.single		= perf_event_init_cpu,
+		.teardown.single	= perf_event_exit_cpu,
+	},
+	[CPUHP_AP_WATCHDOG_ONLINE] = {
+		.name			= "lockup_detector:online",
+		.startup.single		= lockup_detector_online_cpu,
+		.teardown.single	= lockup_detector_offline_cpu,
+	},
+	[CPUHP_AP_WORKQUEUE_ONLINE] = {
+		.name			= "workqueue:online",
+		.startup.single		= workqueue_online_cpu,
+		.teardown.single	= workqueue_offline_cpu,
+	},
+	[CPUHP_AP_RANDOM_ONLINE] = {
+		.name			= "random:online",
+		.startup.single		= random_online_cpu,
+		.teardown.single	= NULL,
+	},
+	[CPUHP_AP_RCUTREE_ONLINE] = {
+		.name			= "RCU/tree:online",
+		.startup.single		= rcutree_online_cpu,
+		.teardown.single	= rcutree_offline_cpu,
+	},
+#endif
+	/*
+	 * The dynamically registered state space is here
+	 */
+
+#ifdef CONFIG_SMP
+	/* Last state is scheduler control setting the cpu active */
+	[CPUHP_AP_ACTIVE] = {
+		.name			= "sched:active",
+		.startup.single		= sched_cpu_activate,
+		.teardown.single	= sched_cpu_deactivate,
+	},
+#endif
+
+	/* CPU is fully up and running. */
+	[CPUHP_ONLINE] = {
+		.name			= "online",
+		.startup.single		= NULL,
+		.teardown.single	= NULL,
+	},
+};
+
+/* Sanity check for callbacks */
+static int cpuhp_cb_check(enum cpuhp_state state)
+{
+	if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE)
+		return -EINVAL;
+	return 0;
+}
+
+/*
+ * Returns a free for dynamic slot assignment of the Online state. The states
+ * are protected by the cpuhp_slot_states mutex and an empty slot is identified
+ * by having no name assigned.
+ */
+static int cpuhp_reserve_state(enum cpuhp_state state)
+{
+	enum cpuhp_state i, end;
+	struct cpuhp_step *step;
+
+	switch (state) {
+	case CPUHP_AP_ONLINE_DYN:
+		step = cpuhp_hp_states + CPUHP_AP_ONLINE_DYN;
+		end = CPUHP_AP_ONLINE_DYN_END;
+		break;
+	case CPUHP_BP_PREPARE_DYN:
+		step = cpuhp_hp_states + CPUHP_BP_PREPARE_DYN;
+		end = CPUHP_BP_PREPARE_DYN_END;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	for (i = state; i <= end; i++, step++) {
+		if (!step->name)
+			return i;
+	}
+	WARN(1, "No more dynamic states available for CPU hotplug\n");
+	return -ENOSPC;
+}
+
+static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name,
+				 int (*startup)(unsigned int cpu),
+				 int (*teardown)(unsigned int cpu),
+				 bool multi_instance)
+{
+	/* (Un)Install the callbacks for further cpu hotplug operations */
+	struct cpuhp_step *sp;
+	int ret = 0;
+
+	/*
+	 * If name is NULL, then the state gets removed.
+	 *
+	 * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on
+	 * the first allocation from these dynamic ranges, so the removal
+	 * would trigger a new allocation and clear the wrong (already
+	 * empty) state, leaving the callbacks of the to be cleared state
+	 * dangling, which causes wreckage on the next hotplug operation.
+	 */
+	if (name && (state == CPUHP_AP_ONLINE_DYN ||
+		     state == CPUHP_BP_PREPARE_DYN)) {
+		ret = cpuhp_reserve_state(state);
+		if (ret < 0)
+			return ret;
+		state = ret;
+	}
+	sp = cpuhp_get_step(state);
+	if (name && sp->name)
+		return -EBUSY;
+
+	sp->startup.single = startup;
+	sp->teardown.single = teardown;
+	sp->name = name;
+	sp->multi_instance = multi_instance;
+	INIT_HLIST_HEAD(&sp->list);
+	return ret;
+}
+
+static void *cpuhp_get_teardown_cb(enum cpuhp_state state)
+{
+	return cpuhp_get_step(state)->teardown.single;
+}
+
+/*
+ * Call the startup/teardown function for a step either on the AP or
+ * on the current CPU.
+ */
+static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup,
+			    struct hlist_node *node)
+{
+	struct cpuhp_step *sp = cpuhp_get_step(state);
+	int ret;
+
+	/*
+	 * If there's nothing to do, we done.
+	 * Relies on the union for multi_instance.
+	 */
+	if (cpuhp_step_empty(bringup, sp))
+		return 0;
+	/*
+	 * The non AP bound callbacks can fail on bringup. On teardown
+	 * e.g. module removal we crash for now.
+	 */
+#ifdef CONFIG_SMP
+	if (cpuhp_is_ap_state(state))
+		ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node);
+	else
+		ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
+#else
+	ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
+#endif
+	BUG_ON(ret && !bringup);
+	return ret;
+}
+
+/*
+ * Called from __cpuhp_setup_state on a recoverable failure.
+ *
+ * Note: The teardown callbacks for rollback are not allowed to fail!
+ */
+static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state,
+				   struct hlist_node *node)
+{
+	int cpu;
+
+	/* Roll back the already executed steps on the other cpus */
+	for_each_present_cpu(cpu) {
+		struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+		int cpustate = st->state;
+
+		if (cpu >= failedcpu)
+			break;
+
+		/* Did we invoke the startup call on that cpu ? */
+		if (cpustate >= state)
+			cpuhp_issue_call(cpu, state, false, node);
+	}
+}
+
+int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state,
+					  struct hlist_node *node,
+					  bool invoke)
+{
+	struct cpuhp_step *sp;
+	int cpu;
+	int ret;
+
+	lockdep_assert_cpus_held();
+
+	sp = cpuhp_get_step(state);
+	if (sp->multi_instance == false)
+		return -EINVAL;
+
+	mutex_lock(&cpuhp_state_mutex);
+
+	if (!invoke || !sp->startup.multi)
+		goto add_node;
+
+	/*
+	 * Try to call the startup callback for each present cpu
+	 * depending on the hotplug state of the cpu.
+	 */
+	for_each_present_cpu(cpu) {
+		struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+		int cpustate = st->state;
+
+		if (cpustate < state)
+			continue;
+
+		ret = cpuhp_issue_call(cpu, state, true, node);
+		if (ret) {
+			if (sp->teardown.multi)
+				cpuhp_rollback_install(cpu, state, node);
+			goto unlock;
+		}
+	}
+add_node:
+	ret = 0;
+	hlist_add_head(node, &sp->list);
+unlock:
+	mutex_unlock(&cpuhp_state_mutex);
+	return ret;
+}
+
+int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node,
+			       bool invoke)
+{
+	int ret;
+
+	cpus_read_lock();
+	ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke);
+	cpus_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance);
+
+/**
+ * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state
+ * @state:		The state to setup
+ * @name:		Name of the step
+ * @invoke:		If true, the startup function is invoked for cpus where
+ *			cpu state >= @state
+ * @startup:		startup callback function
+ * @teardown:		teardown callback function
+ * @multi_instance:	State is set up for multiple instances which get
+ *			added afterwards.
+ *
+ * The caller needs to hold cpus read locked while calling this function.
+ * Return:
+ *   On success:
+ *      Positive state number if @state is CPUHP_AP_ONLINE_DYN;
+ *      0 for all other states
+ *   On failure: proper (negative) error code
+ */
+int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state,
+				   const char *name, bool invoke,
+				   int (*startup)(unsigned int cpu),
+				   int (*teardown)(unsigned int cpu),
+				   bool multi_instance)
+{
+	int cpu, ret = 0;
+	bool dynstate;
+
+	lockdep_assert_cpus_held();
+
+	if (cpuhp_cb_check(state) || !name)
+		return -EINVAL;
+
+	mutex_lock(&cpuhp_state_mutex);
+
+	ret = cpuhp_store_callbacks(state, name, startup, teardown,
+				    multi_instance);
+
+	dynstate = state == CPUHP_AP_ONLINE_DYN;
+	if (ret > 0 && dynstate) {
+		state = ret;
+		ret = 0;
+	}
+
+	if (ret || !invoke || !startup)
+		goto out;
+
+	/*
+	 * Try to call the startup callback for each present cpu
+	 * depending on the hotplug state of the cpu.
+	 */
+	for_each_present_cpu(cpu) {
+		struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+		int cpustate = st->state;
+
+		if (cpustate < state)
+			continue;
+
+		ret = cpuhp_issue_call(cpu, state, true, NULL);
+		if (ret) {
+			if (teardown)
+				cpuhp_rollback_install(cpu, state, NULL);
+			cpuhp_store_callbacks(state, NULL, NULL, NULL, false);
+			goto out;
+		}
+	}
+out:
+	mutex_unlock(&cpuhp_state_mutex);
+	/*
+	 * If the requested state is CPUHP_AP_ONLINE_DYN, return the
+	 * dynamically allocated state in case of success.
+	 */
+	if (!ret && dynstate)
+		return state;
+	return ret;
+}
+EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked);
+
+int __cpuhp_setup_state(enum cpuhp_state state,
+			const char *name, bool invoke,
+			int (*startup)(unsigned int cpu),
+			int (*teardown)(unsigned int cpu),
+			bool multi_instance)
+{
+	int ret;
+
+	cpus_read_lock();
+	ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup,
+					     teardown, multi_instance);
+	cpus_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL(__cpuhp_setup_state);
+
+int __cpuhp_state_remove_instance(enum cpuhp_state state,
+				  struct hlist_node *node, bool invoke)
+{
+	struct cpuhp_step *sp = cpuhp_get_step(state);
+	int cpu;
+
+	BUG_ON(cpuhp_cb_check(state));
+
+	if (!sp->multi_instance)
+		return -EINVAL;
+
+	cpus_read_lock();
+	mutex_lock(&cpuhp_state_mutex);
+
+	if (!invoke || !cpuhp_get_teardown_cb(state))
+		goto remove;
+	/*
+	 * Call the teardown callback for each present cpu depending
+	 * on the hotplug state of the cpu. This function is not
+	 * allowed to fail currently!
+	 */
+	for_each_present_cpu(cpu) {
+		struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+		int cpustate = st->state;
+
+		if (cpustate >= state)
+			cpuhp_issue_call(cpu, state, false, node);
+	}
+
+remove:
+	hlist_del(node);
+	mutex_unlock(&cpuhp_state_mutex);
+	cpus_read_unlock();
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance);
+
+/**
+ * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state
+ * @state:	The state to remove
+ * @invoke:	If true, the teardown function is invoked for cpus where
+ *		cpu state >= @state
+ *
+ * The caller needs to hold cpus read locked while calling this function.
+ * The teardown callback is currently not allowed to fail. Think
+ * about module removal!
+ */
+void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke)
+{
+	struct cpuhp_step *sp = cpuhp_get_step(state);
+	int cpu;
+
+	BUG_ON(cpuhp_cb_check(state));
+
+	lockdep_assert_cpus_held();
+
+	mutex_lock(&cpuhp_state_mutex);
+	if (sp->multi_instance) {
+		WARN(!hlist_empty(&sp->list),
+		     "Error: Removing state %d which has instances left.\n",
+		     state);
+		goto remove;
+	}
+
+	if (!invoke || !cpuhp_get_teardown_cb(state))
+		goto remove;
+
+	/*
+	 * Call the teardown callback for each present cpu depending
+	 * on the hotplug state of the cpu. This function is not
+	 * allowed to fail currently!
+	 */
+	for_each_present_cpu(cpu) {
+		struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+		int cpustate = st->state;
+
+		if (cpustate >= state)
+			cpuhp_issue_call(cpu, state, false, NULL);
+	}
+remove:
+	cpuhp_store_callbacks(state, NULL, NULL, NULL, false);
+	mutex_unlock(&cpuhp_state_mutex);
+}
+EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked);
+
+void __cpuhp_remove_state(enum cpuhp_state state, bool invoke)
+{
+	cpus_read_lock();
+	__cpuhp_remove_state_cpuslocked(state, invoke);
+	cpus_read_unlock();
+}
+EXPORT_SYMBOL(__cpuhp_remove_state);
+
+#ifdef CONFIG_HOTPLUG_SMT
+static void cpuhp_offline_cpu_device(unsigned int cpu)
+{
+	struct device *dev = get_cpu_device(cpu);
+
+	dev->offline = true;
+	/* Tell user space about the state change */
+	kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
+}
+
+static void cpuhp_online_cpu_device(unsigned int cpu)
+{
+	struct device *dev = get_cpu_device(cpu);
+
+	dev->offline = false;
+	/* Tell user space about the state change */
+	kobject_uevent(&dev->kobj, KOBJ_ONLINE);
+}
+
+int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
+{
+	int cpu, ret = 0;
+
+	cpu_maps_update_begin();
+	for_each_online_cpu(cpu) {
+		if (topology_is_primary_thread(cpu))
+			continue;
+		/*
+		 * Disable can be called with CPU_SMT_ENABLED when changing
+		 * from a higher to lower number of SMT threads per core.
+		 */
+		if (ctrlval == CPU_SMT_ENABLED && cpu_smt_thread_allowed(cpu))
+			continue;
+		ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
+		if (ret)
+			break;
+		/*
+		 * As this needs to hold the cpu maps lock it's impossible
+		 * to call device_offline() because that ends up calling
+		 * cpu_down() which takes cpu maps lock. cpu maps lock
+		 * needs to be held as this might race against in kernel
+		 * abusers of the hotplug machinery (thermal management).
+		 *
+		 * So nothing would update device:offline state. That would
+		 * leave the sysfs entry stale and prevent onlining after
+		 * smt control has been changed to 'off' again. This is
+		 * called under the sysfs hotplug lock, so it is properly
+		 * serialized against the regular offline usage.
+		 */
+		cpuhp_offline_cpu_device(cpu);
+	}
+	if (!ret)
+		cpu_smt_control = ctrlval;
+	cpu_maps_update_done();
+	return ret;
+}
+
+int cpuhp_smt_enable(void)
+{
+	int cpu, ret = 0;
+
+	cpu_maps_update_begin();
+	cpu_smt_control = CPU_SMT_ENABLED;
+	for_each_present_cpu(cpu) {
+		/* Skip online CPUs and CPUs on offline nodes */
+		if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))
+			continue;
+		if (!cpu_smt_thread_allowed(cpu))
+			continue;
+		ret = _cpu_up(cpu, 0, CPUHP_ONLINE);
+		if (ret)
+			break;
+		/* See comment in cpuhp_smt_disable() */
+		cpuhp_online_cpu_device(cpu);
+	}
+	cpu_maps_update_done();
+	return ret;
+}
+#endif
+
+#if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU)
+static ssize_t state_show(struct device *dev,
+			  struct device_attribute *attr, char *buf)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
+
+	return sprintf(buf, "%d\n", st->state);
+}
+static DEVICE_ATTR_RO(state);
+
+static ssize_t target_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
+	struct cpuhp_step *sp;
+	int target, ret;
+
+	ret = kstrtoint(buf, 10, &target);
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL
+	if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE)
+		return -EINVAL;
+#else
+	if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE)
+		return -EINVAL;
+#endif
+
+	ret = lock_device_hotplug_sysfs();
+	if (ret)
+		return ret;
+
+	mutex_lock(&cpuhp_state_mutex);
+	sp = cpuhp_get_step(target);
+	ret = !sp->name || sp->cant_stop ? -EINVAL : 0;
+	mutex_unlock(&cpuhp_state_mutex);
+	if (ret)
+		goto out;
+
+	if (st->state < target)
+		ret = cpu_up(dev->id, target);
+	else if (st->state > target)
+		ret = cpu_down(dev->id, target);
+	else if (WARN_ON(st->target != target))
+		st->target = target;
+out:
+	unlock_device_hotplug();
+	return ret ? ret : count;
+}
+
+static ssize_t target_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
+
+	return sprintf(buf, "%d\n", st->target);
+}
+static DEVICE_ATTR_RW(target);
+
+static ssize_t fail_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
+	struct cpuhp_step *sp;
+	int fail, ret;
+
+	ret = kstrtoint(buf, 10, &fail);
+	if (ret)
+		return ret;
+
+	if (fail == CPUHP_INVALID) {
+		st->fail = fail;
+		return count;
+	}
+
+	if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE)
+		return -EINVAL;
+
+	/*
+	 * Cannot fail STARTING/DYING callbacks.
+	 */
+	if (cpuhp_is_atomic_state(fail))
+		return -EINVAL;
+
+	/*
+	 * DEAD callbacks cannot fail...
+	 * ... neither can CPUHP_BRINGUP_CPU during hotunplug. The latter
+	 * triggering STARTING callbacks, a failure in this state would
+	 * hinder rollback.
+	 */
+	if (fail <= CPUHP_BRINGUP_CPU && st->state > CPUHP_BRINGUP_CPU)
+		return -EINVAL;
+
+	/*
+	 * Cannot fail anything that doesn't have callbacks.
+	 */
+	mutex_lock(&cpuhp_state_mutex);
+	sp = cpuhp_get_step(fail);
+	if (!sp->startup.single && !sp->teardown.single)
+		ret = -EINVAL;
+	mutex_unlock(&cpuhp_state_mutex);
+	if (ret)
+		return ret;
+
+	st->fail = fail;
+
+	return count;
+}
+
+static ssize_t fail_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
+
+	return sprintf(buf, "%d\n", st->fail);
+}
+
+static DEVICE_ATTR_RW(fail);
+
+static struct attribute *cpuhp_cpu_attrs[] = {
+	&dev_attr_state.attr,
+	&dev_attr_target.attr,
+	&dev_attr_fail.attr,
+	NULL
+};
+
+static const struct attribute_group cpuhp_cpu_attr_group = {
+	.attrs = cpuhp_cpu_attrs,
+	.name = "hotplug",
+	NULL
+};
+
+static ssize_t states_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	ssize_t cur, res = 0;
+	int i;
+
+	mutex_lock(&cpuhp_state_mutex);
+	for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) {
+		struct cpuhp_step *sp = cpuhp_get_step(i);
+
+		if (sp->name) {
+			cur = sprintf(buf, "%3d: %s\n", i, sp->name);
+			buf += cur;
+			res += cur;
+		}
+	}
+	mutex_unlock(&cpuhp_state_mutex);
+	return res;
+}
+static DEVICE_ATTR_RO(states);
+
+static struct attribute *cpuhp_cpu_root_attrs[] = {
+	&dev_attr_states.attr,
+	NULL
+};
+
+static const struct attribute_group cpuhp_cpu_root_attr_group = {
+	.attrs = cpuhp_cpu_root_attrs,
+	.name = "hotplug",
+	NULL
+};
+
+#ifdef CONFIG_HOTPLUG_SMT
+
+static ssize_t
+__store_smt_control(struct device *dev, struct device_attribute *attr,
+		    const char *buf, size_t count)
+{
+	int ctrlval, ret;
+
+	if (sysfs_streq(buf, "on"))
+		ctrlval = CPU_SMT_ENABLED;
+	else if (sysfs_streq(buf, "off"))
+		ctrlval = CPU_SMT_DISABLED;
+	else if (sysfs_streq(buf, "forceoff"))
+		ctrlval = CPU_SMT_FORCE_DISABLED;
+	else
+		return -EINVAL;
+
+	if (cpu_smt_control == CPU_SMT_FORCE_DISABLED)
+		return -EPERM;
+
+	if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED)
+		return -ENODEV;
+
+	ret = lock_device_hotplug_sysfs();
+	if (ret)
+		return ret;
+
+	if (ctrlval != cpu_smt_control) {
+		switch (ctrlval) {
+		case CPU_SMT_ENABLED:
+			ret = cpuhp_smt_enable();
+			break;
+		case CPU_SMT_DISABLED:
+		case CPU_SMT_FORCE_DISABLED:
+			ret = cpuhp_smt_disable(ctrlval);
+			break;
+		}
+	}
+
+	unlock_device_hotplug();
+	return ret ? ret : count;
+}
+
+#else /* !CONFIG_HOTPLUG_SMT */
+static ssize_t
+__store_smt_control(struct device *dev, struct device_attribute *attr,
+		    const char *buf, size_t count)
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_HOTPLUG_SMT */
+
+static const char *smt_states[] = {
+	[CPU_SMT_ENABLED]		= "on",
+	[CPU_SMT_DISABLED]		= "off",
+	[CPU_SMT_FORCE_DISABLED]	= "forceoff",
+	[CPU_SMT_NOT_SUPPORTED]		= "notsupported",
+	[CPU_SMT_NOT_IMPLEMENTED]	= "notimplemented",
+};
+
+static ssize_t control_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	const char *state = smt_states[cpu_smt_control];
+
+	return snprintf(buf, PAGE_SIZE - 2, "%s\n", state);
+}
+
+static ssize_t control_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	return __store_smt_control(dev, attr, buf, count);
+}
+static DEVICE_ATTR_RW(control);
+
+static ssize_t active_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active());
+}
+static DEVICE_ATTR_RO(active);
+
+static struct attribute *cpuhp_smt_attrs[] = {
+	&dev_attr_control.attr,
+	&dev_attr_active.attr,
+	NULL
+};
+
+static const struct attribute_group cpuhp_smt_attr_group = {
+	.attrs = cpuhp_smt_attrs,
+	.name = "smt",
+	NULL
+};
+
+static int __init cpu_smt_sysfs_init(void)
+{
+	return sysfs_create_group(&cpu_subsys.dev_root->kobj,
+				  &cpuhp_smt_attr_group);
+}
+
+static int __init cpuhp_sysfs_init(void)
+{
+	int cpu, ret;
+
+	ret = cpu_smt_sysfs_init();
+	if (ret)
+		return ret;
+
+	ret = sysfs_create_group(&cpu_subsys.dev_root->kobj,
+				 &cpuhp_cpu_root_attr_group);
+	if (ret)
+		return ret;
+
+	for_each_possible_cpu(cpu) {
+		struct device *dev = get_cpu_device(cpu);
+
+		if (!dev)
+			continue;
+		ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+device_initcall(cpuhp_sysfs_init);
+#endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */
+
+/*
+ * cpu_bit_bitmap[] is a special, "compressed" data structure that
+ * represents all NR_CPUS bits binary values of 1<<nr.
+ *
+ * It is used by cpumask_of() to get a constant address to a CPU
+ * mask value that has a single bit set only.
+ */
+
+/* cpu_bit_bitmap[0] is empty - so we can back into it */
+#define MASK_DECLARE_1(x)	[x+1][0] = (1UL << (x))
+#define MASK_DECLARE_2(x)	MASK_DECLARE_1(x), MASK_DECLARE_1(x+1)
+#define MASK_DECLARE_4(x)	MASK_DECLARE_2(x), MASK_DECLARE_2(x+2)
+#define MASK_DECLARE_8(x)	MASK_DECLARE_4(x), MASK_DECLARE_4(x+4)
+
+const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = {
+
+	MASK_DECLARE_8(0),	MASK_DECLARE_8(8),
+	MASK_DECLARE_8(16),	MASK_DECLARE_8(24),
+#if BITS_PER_LONG > 32
+	MASK_DECLARE_8(32),	MASK_DECLARE_8(40),
+	MASK_DECLARE_8(48),	MASK_DECLARE_8(56),
+#endif
+};
+EXPORT_SYMBOL_GPL(cpu_bit_bitmap);
+
+const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
+EXPORT_SYMBOL(cpu_all_bits);
+
+#ifdef CONFIG_INIT_ALL_POSSIBLE
+struct cpumask __cpu_possible_mask __read_mostly
+	= {CPU_BITS_ALL};
+#else
+struct cpumask __cpu_possible_mask __read_mostly;
+#endif
+EXPORT_SYMBOL(__cpu_possible_mask);
+
+struct cpumask __cpu_online_mask __read_mostly;
+EXPORT_SYMBOL(__cpu_online_mask);
+
+struct cpumask __cpu_present_mask __read_mostly;
+EXPORT_SYMBOL(__cpu_present_mask);
+
+struct cpumask __cpu_active_mask __read_mostly;
+EXPORT_SYMBOL(__cpu_active_mask);
+
+struct cpumask __cpu_dying_mask __read_mostly;
+EXPORT_SYMBOL(__cpu_dying_mask);
+
+atomic_t __num_online_cpus __read_mostly;
+EXPORT_SYMBOL(__num_online_cpus);
+
+void init_cpu_present(const struct cpumask *src)
+{
+	cpumask_copy(&__cpu_present_mask, src);
+}
+
+void init_cpu_possible(const struct cpumask *src)
+{
+	cpumask_copy(&__cpu_possible_mask, src);
+}
+
+void init_cpu_online(const struct cpumask *src)
+{
+	cpumask_copy(&__cpu_online_mask, src);
+}
+
+void set_cpu_online(unsigned int cpu, bool online)
+{
+	/*
+	 * atomic_inc/dec() is required to handle the horrid abuse of this
+	 * function by the reboot and kexec code which invoke it from
+	 * IPI/NMI broadcasts when shutting down CPUs. Invocation from
+	 * regular CPU hotplug is properly serialized.
+	 *
+	 * Note, that the fact that __num_online_cpus is of type atomic_t
+	 * does not protect readers which are not serialized against
+	 * concurrent hotplug operations.
+	 */
+	if (online) {
+		if (!cpumask_test_and_set_cpu(cpu, &__cpu_online_mask))
+			atomic_inc(&__num_online_cpus);
+	} else {
+		if (cpumask_test_and_clear_cpu(cpu, &__cpu_online_mask))
+			atomic_dec(&__num_online_cpus);
+	}
+}
+
+/*
+ * Activate the first processor.
+ */
+void __init boot_cpu_init(void)
+{
+	int cpu = smp_processor_id();
+
+	/* Mark the boot cpu "present", "online" etc for SMP and UP case */
+	set_cpu_online(cpu, true);
+	set_cpu_active(cpu, true);
+	set_cpu_present(cpu, true);
+	set_cpu_possible(cpu, true);
+
+#ifdef CONFIG_SMP
+	__boot_cpu_id = cpu;
+#endif
+}
+
+/*
+ * Must be called _AFTER_ setting up the per_cpu areas
+ */
+void __init boot_cpu_hotplug_init(void)
+{
+#ifdef CONFIG_SMP
+	cpumask_set_cpu(smp_processor_id(), &cpus_booted_once_mask);
+#endif
+	this_cpu_write(cpuhp_state.state, CPUHP_ONLINE);
+}
+
+/*
+ * These are used for a global "mitigations=" cmdline option for toggling
+ * optional CPU mitigations.
+ */
+enum cpu_mitigations {
+	CPU_MITIGATIONS_OFF,
+	CPU_MITIGATIONS_AUTO,
+	CPU_MITIGATIONS_AUTO_NOSMT,
+};
+
+static enum cpu_mitigations cpu_mitigations __ro_after_init =
+	CPU_MITIGATIONS_AUTO;
+
+static int __init mitigations_parse_cmdline(char *arg)
+{
+	if (!strcmp(arg, "off"))
+		cpu_mitigations = CPU_MITIGATIONS_OFF;
+	else if (!strcmp(arg, "auto"))
+		cpu_mitigations = CPU_MITIGATIONS_AUTO;
+	else if (!strcmp(arg, "auto,nosmt"))
+		cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT;
+	else
+		pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n",
+			arg);
+
+	return 0;
+}
+early_param("mitigations", mitigations_parse_cmdline);
+
+/* mitigations=off */
+bool cpu_mitigations_off(void)
+{
+	return cpu_mitigations == CPU_MITIGATIONS_OFF;
+}
+EXPORT_SYMBOL_GPL(cpu_mitigations_off);
+
+/* mitigations=auto,nosmt */
+bool cpu_mitigations_auto_nosmt(void)
+{
+	return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT;
+}
+EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt);
diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c
new file mode 100644
index 000000000..ba4ba71fa
--- /dev/null
+++ b/kernel/cpu_pm.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Author:
+ *	Colin Cross <ccross@android.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/cpu_pm.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/spinlock.h>
+#include <linux/syscore_ops.h>
+
+/*
+ * atomic_notifiers use a spinlock_t, which can block under PREEMPT_RT.
+ * Notifications for cpu_pm will be issued by the idle task itself, which can
+ * never block, IOW it requires using a raw_spinlock_t.
+ */
+static struct {
+	struct raw_notifier_head chain;
+	raw_spinlock_t lock;
+} cpu_pm_notifier = {
+	.chain = RAW_NOTIFIER_INIT(cpu_pm_notifier.chain),
+	.lock  = __RAW_SPIN_LOCK_UNLOCKED(cpu_pm_notifier.lock),
+};
+
+static int cpu_pm_notify(enum cpu_pm_event event)
+{
+	int ret;
+
+	/*
+	 * This introduces a RCU read critical section, which could be
+	 * disfunctional in cpu idle. Copy RCU_NONIDLE code to let RCU know
+	 * this.
+	 */
+	ct_irq_enter_irqson();
+	rcu_read_lock();
+	ret = raw_notifier_call_chain(&cpu_pm_notifier.chain, event, NULL);
+	rcu_read_unlock();
+	ct_irq_exit_irqson();
+
+	return notifier_to_errno(ret);
+}
+
+static int cpu_pm_notify_robust(enum cpu_pm_event event_up, enum cpu_pm_event event_down)
+{
+	unsigned long flags;
+	int ret;
+
+	ct_irq_enter_irqson();
+	raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags);
+	ret = raw_notifier_call_chain_robust(&cpu_pm_notifier.chain, event_up, event_down, NULL);
+	raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags);
+	ct_irq_exit_irqson();
+
+	return notifier_to_errno(ret);
+}
+
+/**
+ * cpu_pm_register_notifier - register a driver with cpu_pm
+ * @nb: notifier block to register
+ *
+ * Add a driver to a list of drivers that are notified about
+ * CPU and CPU cluster low power entry and exit.
+ *
+ * This function has the same return conditions as raw_notifier_chain_register.
+ */
+int cpu_pm_register_notifier(struct notifier_block *nb)
+{
+	unsigned long flags;
+	int ret;
+
+	raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags);
+	ret = raw_notifier_chain_register(&cpu_pm_notifier.chain, nb);
+	raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cpu_pm_register_notifier);
+
+/**
+ * cpu_pm_unregister_notifier - unregister a driver with cpu_pm
+ * @nb: notifier block to be unregistered
+ *
+ * Remove a driver from the CPU PM notifier list.
+ *
+ * This function has the same return conditions as raw_notifier_chain_unregister.
+ */
+int cpu_pm_unregister_notifier(struct notifier_block *nb)
+{
+	unsigned long flags;
+	int ret;
+
+	raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags);
+	ret = raw_notifier_chain_unregister(&cpu_pm_notifier.chain, nb);
+	raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
+
+/**
+ * cpu_pm_enter - CPU low power entry notifier
+ *
+ * Notifies listeners that a single CPU is entering a low power state that may
+ * cause some blocks in the same power domain as the cpu to reset.
+ *
+ * Must be called on the affected CPU with interrupts disabled.  Platform is
+ * responsible for ensuring that cpu_pm_enter is not called twice on the same
+ * CPU before cpu_pm_exit is called. Notified drivers can include VFP
+ * co-processor, interrupt controller and its PM extensions, local CPU
+ * timers context save/restore which shouldn't be interrupted. Hence it
+ * must be called with interrupts disabled.
+ *
+ * Return conditions are same as __raw_notifier_call_chain.
+ */
+int cpu_pm_enter(void)
+{
+	return cpu_pm_notify_robust(CPU_PM_ENTER, CPU_PM_ENTER_FAILED);
+}
+EXPORT_SYMBOL_GPL(cpu_pm_enter);
+
+/**
+ * cpu_pm_exit - CPU low power exit notifier
+ *
+ * Notifies listeners that a single CPU is exiting a low power state that may
+ * have caused some blocks in the same power domain as the cpu to reset.
+ *
+ * Notified drivers can include VFP co-processor, interrupt controller
+ * and its PM extensions, local CPU timers context save/restore which
+ * shouldn't be interrupted. Hence it must be called with interrupts disabled.
+ *
+ * Return conditions are same as __raw_notifier_call_chain.
+ */
+int cpu_pm_exit(void)
+{
+	return cpu_pm_notify(CPU_PM_EXIT);
+}
+EXPORT_SYMBOL_GPL(cpu_pm_exit);
+
+/**
+ * cpu_cluster_pm_enter - CPU cluster low power entry notifier
+ *
+ * Notifies listeners that all cpus in a power domain are entering a low power
+ * state that may cause some blocks in the same power domain to reset.
+ *
+ * Must be called after cpu_pm_enter has been called on all cpus in the power
+ * domain, and before cpu_pm_exit has been called on any cpu in the power
+ * domain. Notified drivers can include VFP co-processor, interrupt controller
+ * and its PM extensions, local CPU timers context save/restore which
+ * shouldn't be interrupted. Hence it must be called with interrupts disabled.
+ *
+ * Must be called with interrupts disabled.
+ *
+ * Return conditions are same as __raw_notifier_call_chain.
+ */
+int cpu_cluster_pm_enter(void)
+{
+	return cpu_pm_notify_robust(CPU_CLUSTER_PM_ENTER, CPU_CLUSTER_PM_ENTER_FAILED);
+}
+EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter);
+
+/**
+ * cpu_cluster_pm_exit - CPU cluster low power exit notifier
+ *
+ * Notifies listeners that all cpus in a power domain are exiting form a
+ * low power state that may have caused some blocks in the same power domain
+ * to reset.
+ *
+ * Must be called after cpu_cluster_pm_enter has been called for the power
+ * domain, and before cpu_pm_exit has been called on any cpu in the power
+ * domain. Notified drivers can include VFP co-processor, interrupt controller
+ * and its PM extensions, local CPU timers context save/restore which
+ * shouldn't be interrupted. Hence it must be called with interrupts disabled.
+ *
+ * Return conditions are same as __raw_notifier_call_chain.
+ */
+int cpu_cluster_pm_exit(void)
+{
+	return cpu_pm_notify(CPU_CLUSTER_PM_EXIT);
+}
+EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
+
+#ifdef CONFIG_PM
+static int cpu_pm_suspend(void)
+{
+	int ret;
+
+	ret = cpu_pm_enter();
+	if (ret)
+		return ret;
+
+	ret = cpu_cluster_pm_enter();
+	return ret;
+}
+
+static void cpu_pm_resume(void)
+{
+	cpu_cluster_pm_exit();
+	cpu_pm_exit();
+}
+
+static struct syscore_ops cpu_pm_syscore_ops = {
+	.suspend = cpu_pm_suspend,
+	.resume = cpu_pm_resume,
+};
+
+static int cpu_pm_init(void)
+{
+	register_syscore_ops(&cpu_pm_syscore_ops);
+	return 0;
+}
+core_initcall(cpu_pm_init);
+#endif
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
new file mode 100644
index 000000000..a0eb4d5cf
--- /dev/null
+++ b/kernel/crash_core.c
@@ -0,0 +1,514 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * crash.c - kernel crash support code.
+ * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
+ */
+
+#include <linux/buildid.h>
+#include <linux/crash_core.h>
+#include <linux/init.h>
+#include <linux/utsname.h>
+#include <linux/vmalloc.h>
+#include <linux/sizes.h>
+
+#include <asm/page.h>
+#include <asm/sections.h>
+
+#include <crypto/sha1.h>
+
+#include "kallsyms_internal.h"
+
+/* vmcoreinfo stuff */
+unsigned char *vmcoreinfo_data;
+size_t vmcoreinfo_size;
+u32 *vmcoreinfo_note;
+
+/* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
+static unsigned char *vmcoreinfo_data_safecopy;
+
+/*
+ * parsing the "crashkernel" commandline
+ *
+ * this code is intended to be called from architecture specific code
+ */
+
+
+/*
+ * This function parses command lines in the format
+ *
+ *   crashkernel=ramsize-range:size[,...][@offset]
+ *
+ * The function returns 0 on success and -EINVAL on failure.
+ */
+static int __init parse_crashkernel_mem(char *cmdline,
+					unsigned long long system_ram,
+					unsigned long long *crash_size,
+					unsigned long long *crash_base)
+{
+	char *cur = cmdline, *tmp;
+	unsigned long long total_mem = system_ram;
+
+	/*
+	 * Firmware sometimes reserves some memory regions for its own use,
+	 * so the system memory size is less than the actual physical memory
+	 * size. Work around this by rounding up the total size to 128M,
+	 * which is enough for most test cases.
+	 */
+	total_mem = roundup(total_mem, SZ_128M);
+
+	/* for each entry of the comma-separated list */
+	do {
+		unsigned long long start, end = ULLONG_MAX, size;
+
+		/* get the start of the range */
+		start = memparse(cur, &tmp);
+		if (cur == tmp) {
+			pr_warn("crashkernel: Memory value expected\n");
+			return -EINVAL;
+		}
+		cur = tmp;
+		if (*cur != '-') {
+			pr_warn("crashkernel: '-' expected\n");
+			return -EINVAL;
+		}
+		cur++;
+
+		/* if no ':' is here, than we read the end */
+		if (*cur != ':') {
+			end = memparse(cur, &tmp);
+			if (cur == tmp) {
+				pr_warn("crashkernel: Memory value expected\n");
+				return -EINVAL;
+			}
+			cur = tmp;
+			if (end <= start) {
+				pr_warn("crashkernel: end <= start\n");
+				return -EINVAL;
+			}
+		}
+
+		if (*cur != ':') {
+			pr_warn("crashkernel: ':' expected\n");
+			return -EINVAL;
+		}
+		cur++;
+
+		size = memparse(cur, &tmp);
+		if (cur == tmp) {
+			pr_warn("Memory value expected\n");
+			return -EINVAL;
+		}
+		cur = tmp;
+		if (size >= total_mem) {
+			pr_warn("crashkernel: invalid size\n");
+			return -EINVAL;
+		}
+
+		/* match ? */
+		if (total_mem >= start && total_mem < end) {
+			*crash_size = size;
+			break;
+		}
+	} while (*cur++ == ',');
+
+	if (*crash_size > 0) {
+		while (*cur && *cur != ' ' && *cur != '@')
+			cur++;
+		if (*cur == '@') {
+			cur++;
+			*crash_base = memparse(cur, &tmp);
+			if (cur == tmp) {
+				pr_warn("Memory value expected after '@'\n");
+				return -EINVAL;
+			}
+		}
+	} else
+		pr_info("crashkernel size resulted in zero bytes\n");
+
+	return 0;
+}
+
+/*
+ * That function parses "simple" (old) crashkernel command lines like
+ *
+ *	crashkernel=size[@offset]
+ *
+ * It returns 0 on success and -EINVAL on failure.
+ */
+static int __init parse_crashkernel_simple(char *cmdline,
+					   unsigned long long *crash_size,
+					   unsigned long long *crash_base)
+{
+	char *cur = cmdline;
+
+	*crash_size = memparse(cmdline, &cur);
+	if (cmdline == cur) {
+		pr_warn("crashkernel: memory value expected\n");
+		return -EINVAL;
+	}
+
+	if (*cur == '@')
+		*crash_base = memparse(cur+1, &cur);
+	else if (*cur != ' ' && *cur != '\0') {
+		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+#define SUFFIX_HIGH 0
+#define SUFFIX_LOW  1
+#define SUFFIX_NULL 2
+static __initdata char *suffix_tbl[] = {
+	[SUFFIX_HIGH] = ",high",
+	[SUFFIX_LOW]  = ",low",
+	[SUFFIX_NULL] = NULL,
+};
+
+/*
+ * That function parses "suffix"  crashkernel command lines like
+ *
+ *	crashkernel=size,[high|low]
+ *
+ * It returns 0 on success and -EINVAL on failure.
+ */
+static int __init parse_crashkernel_suffix(char *cmdline,
+					   unsigned long long	*crash_size,
+					   const char *suffix)
+{
+	char *cur = cmdline;
+
+	*crash_size = memparse(cmdline, &cur);
+	if (cmdline == cur) {
+		pr_warn("crashkernel: memory value expected\n");
+		return -EINVAL;
+	}
+
+	/* check with suffix */
+	if (strncmp(cur, suffix, strlen(suffix))) {
+		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
+		return -EINVAL;
+	}
+	cur += strlen(suffix);
+	if (*cur != ' ' && *cur != '\0') {
+		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static __init char *get_last_crashkernel(char *cmdline,
+			     const char *name,
+			     const char *suffix)
+{
+	char *p = cmdline, *ck_cmdline = NULL;
+
+	/* find crashkernel and use the last one if there are more */
+	p = strstr(p, name);
+	while (p) {
+		char *end_p = strchr(p, ' ');
+		char *q;
+
+		if (!end_p)
+			end_p = p + strlen(p);
+
+		if (!suffix) {
+			int i;
+
+			/* skip the one with any known suffix */
+			for (i = 0; suffix_tbl[i]; i++) {
+				q = end_p - strlen(suffix_tbl[i]);
+				if (!strncmp(q, suffix_tbl[i],
+					     strlen(suffix_tbl[i])))
+					goto next;
+			}
+			ck_cmdline = p;
+		} else {
+			q = end_p - strlen(suffix);
+			if (!strncmp(q, suffix, strlen(suffix)))
+				ck_cmdline = p;
+		}
+next:
+		p = strstr(p+1, name);
+	}
+
+	return ck_cmdline;
+}
+
+static int __init __parse_crashkernel(char *cmdline,
+			     unsigned long long system_ram,
+			     unsigned long long *crash_size,
+			     unsigned long long *crash_base,
+			     const char *name,
+			     const char *suffix)
+{
+	char	*first_colon, *first_space;
+	char	*ck_cmdline;
+
+	BUG_ON(!crash_size || !crash_base);
+	*crash_size = 0;
+	*crash_base = 0;
+
+	ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
+	if (!ck_cmdline)
+		return -ENOENT;
+
+	ck_cmdline += strlen(name);
+
+	if (suffix)
+		return parse_crashkernel_suffix(ck_cmdline, crash_size,
+				suffix);
+	/*
+	 * if the commandline contains a ':', then that's the extended
+	 * syntax -- if not, it must be the classic syntax
+	 */
+	first_colon = strchr(ck_cmdline, ':');
+	first_space = strchr(ck_cmdline, ' ');
+	if (first_colon && (!first_space || first_colon < first_space))
+		return parse_crashkernel_mem(ck_cmdline, system_ram,
+				crash_size, crash_base);
+
+	return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
+}
+
+/*
+ * That function is the entry point for command line parsing and should be
+ * called from the arch-specific code.
+ */
+int __init parse_crashkernel(char *cmdline,
+			     unsigned long long system_ram,
+			     unsigned long long *crash_size,
+			     unsigned long long *crash_base)
+{
+	return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
+					"crashkernel=", NULL);
+}
+
+int __init parse_crashkernel_high(char *cmdline,
+			     unsigned long long system_ram,
+			     unsigned long long *crash_size,
+			     unsigned long long *crash_base)
+{
+	return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
+				"crashkernel=", suffix_tbl[SUFFIX_HIGH]);
+}
+
+int __init parse_crashkernel_low(char *cmdline,
+			     unsigned long long system_ram,
+			     unsigned long long *crash_size,
+			     unsigned long long *crash_base)
+{
+	return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
+				"crashkernel=", suffix_tbl[SUFFIX_LOW]);
+}
+
+/*
+ * Add a dummy early_param handler to mark crashkernel= as a known command line
+ * parameter and suppress incorrect warnings in init/main.c.
+ */
+static int __init parse_crashkernel_dummy(char *arg)
+{
+	return 0;
+}
+early_param("crashkernel", parse_crashkernel_dummy);
+
+Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
+			  void *data, size_t data_len)
+{
+	struct elf_note *note = (struct elf_note *)buf;
+
+	note->n_namesz = strlen(name) + 1;
+	note->n_descsz = data_len;
+	note->n_type   = type;
+	buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf_Word));
+	memcpy(buf, name, note->n_namesz);
+	buf += DIV_ROUND_UP(note->n_namesz, sizeof(Elf_Word));
+	memcpy(buf, data, data_len);
+	buf += DIV_ROUND_UP(data_len, sizeof(Elf_Word));
+
+	return buf;
+}
+
+void final_note(Elf_Word *buf)
+{
+	memset(buf, 0, sizeof(struct elf_note));
+}
+
+static void update_vmcoreinfo_note(void)
+{
+	u32 *buf = vmcoreinfo_note;
+
+	if (!vmcoreinfo_size)
+		return;
+	buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
+			      vmcoreinfo_size);
+	final_note(buf);
+}
+
+void crash_update_vmcoreinfo_safecopy(void *ptr)
+{
+	if (ptr)
+		memcpy(ptr, vmcoreinfo_data, vmcoreinfo_size);
+
+	vmcoreinfo_data_safecopy = ptr;
+}
+
+void crash_save_vmcoreinfo(void)
+{
+	if (!vmcoreinfo_note)
+		return;
+
+	/* Use the safe copy to generate vmcoreinfo note if have */
+	if (vmcoreinfo_data_safecopy)
+		vmcoreinfo_data = vmcoreinfo_data_safecopy;
+
+	vmcoreinfo_append_str("CRASHTIME=%lld\n", ktime_get_real_seconds());
+	update_vmcoreinfo_note();
+}
+
+void vmcoreinfo_append_str(const char *fmt, ...)
+{
+	va_list args;
+	char buf[0x50];
+	size_t r;
+
+	va_start(args, fmt);
+	r = vscnprintf(buf, sizeof(buf), fmt, args);
+	va_end(args);
+
+	r = min(r, (size_t)VMCOREINFO_BYTES - vmcoreinfo_size);
+
+	memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
+
+	vmcoreinfo_size += r;
+}
+
+/*
+ * provide an empty default implementation here -- architecture
+ * code may override this
+ */
+void __weak arch_crash_save_vmcoreinfo(void)
+{}
+
+phys_addr_t __weak paddr_vmcoreinfo_note(void)
+{
+	return __pa(vmcoreinfo_note);
+}
+EXPORT_SYMBOL(paddr_vmcoreinfo_note);
+
+static int __init crash_save_vmcoreinfo_init(void)
+{
+	vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL);
+	if (!vmcoreinfo_data) {
+		pr_warn("Memory allocation for vmcoreinfo_data failed\n");
+		return -ENOMEM;
+	}
+
+	vmcoreinfo_note = alloc_pages_exact(VMCOREINFO_NOTE_SIZE,
+						GFP_KERNEL | __GFP_ZERO);
+	if (!vmcoreinfo_note) {
+		free_page((unsigned long)vmcoreinfo_data);
+		vmcoreinfo_data = NULL;
+		pr_warn("Memory allocation for vmcoreinfo_note failed\n");
+		return -ENOMEM;
+	}
+
+	VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
+	VMCOREINFO_BUILD_ID();
+	VMCOREINFO_PAGESIZE(PAGE_SIZE);
+
+	VMCOREINFO_SYMBOL(init_uts_ns);
+	VMCOREINFO_OFFSET(uts_namespace, name);
+	VMCOREINFO_SYMBOL(node_online_map);
+#ifdef CONFIG_MMU
+	VMCOREINFO_SYMBOL_ARRAY(swapper_pg_dir);
+#endif
+	VMCOREINFO_SYMBOL(_stext);
+	VMCOREINFO_SYMBOL(vmap_area_list);
+
+#ifndef CONFIG_NUMA
+	VMCOREINFO_SYMBOL(mem_map);
+	VMCOREINFO_SYMBOL(contig_page_data);
+#endif
+#ifdef CONFIG_SPARSEMEM
+	VMCOREINFO_SYMBOL_ARRAY(mem_section);
+	VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
+	VMCOREINFO_STRUCT_SIZE(mem_section);
+	VMCOREINFO_OFFSET(mem_section, section_mem_map);
+	VMCOREINFO_NUMBER(SECTION_SIZE_BITS);
+	VMCOREINFO_NUMBER(MAX_PHYSMEM_BITS);
+#endif
+	VMCOREINFO_STRUCT_SIZE(page);
+	VMCOREINFO_STRUCT_SIZE(pglist_data);
+	VMCOREINFO_STRUCT_SIZE(zone);
+	VMCOREINFO_STRUCT_SIZE(free_area);
+	VMCOREINFO_STRUCT_SIZE(list_head);
+	VMCOREINFO_SIZE(nodemask_t);
+	VMCOREINFO_OFFSET(page, flags);
+	VMCOREINFO_OFFSET(page, _refcount);
+	VMCOREINFO_OFFSET(page, mapping);
+	VMCOREINFO_OFFSET(page, lru);
+	VMCOREINFO_OFFSET(page, _mapcount);
+	VMCOREINFO_OFFSET(page, private);
+	VMCOREINFO_OFFSET(page, compound_dtor);
+	VMCOREINFO_OFFSET(page, compound_order);
+	VMCOREINFO_OFFSET(page, compound_head);
+	VMCOREINFO_OFFSET(pglist_data, node_zones);
+	VMCOREINFO_OFFSET(pglist_data, nr_zones);
+#ifdef CONFIG_FLATMEM
+	VMCOREINFO_OFFSET(pglist_data, node_mem_map);
+#endif
+	VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
+	VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
+	VMCOREINFO_OFFSET(pglist_data, node_id);
+	VMCOREINFO_OFFSET(zone, free_area);
+	VMCOREINFO_OFFSET(zone, vm_stat);
+	VMCOREINFO_OFFSET(zone, spanned_pages);
+	VMCOREINFO_OFFSET(free_area, free_list);
+	VMCOREINFO_OFFSET(list_head, next);
+	VMCOREINFO_OFFSET(list_head, prev);
+	VMCOREINFO_OFFSET(vmap_area, va_start);
+	VMCOREINFO_OFFSET(vmap_area, list);
+	VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
+	log_buf_vmcoreinfo_setup();
+	VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
+	VMCOREINFO_NUMBER(NR_FREE_PAGES);
+	VMCOREINFO_NUMBER(PG_lru);
+	VMCOREINFO_NUMBER(PG_private);
+	VMCOREINFO_NUMBER(PG_swapcache);
+	VMCOREINFO_NUMBER(PG_swapbacked);
+	VMCOREINFO_NUMBER(PG_slab);
+#ifdef CONFIG_MEMORY_FAILURE
+	VMCOREINFO_NUMBER(PG_hwpoison);
+#endif
+	VMCOREINFO_NUMBER(PG_head_mask);
+#define PAGE_BUDDY_MAPCOUNT_VALUE	(~PG_buddy)
+	VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
+#ifdef CONFIG_HUGETLB_PAGE
+	VMCOREINFO_NUMBER(HUGETLB_PAGE_DTOR);
+#define PAGE_OFFLINE_MAPCOUNT_VALUE	(~PG_offline)
+	VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE);
+#endif
+
+#ifdef CONFIG_KALLSYMS
+	VMCOREINFO_SYMBOL(kallsyms_names);
+	VMCOREINFO_SYMBOL(kallsyms_num_syms);
+	VMCOREINFO_SYMBOL(kallsyms_token_table);
+	VMCOREINFO_SYMBOL(kallsyms_token_index);
+#ifdef CONFIG_KALLSYMS_BASE_RELATIVE
+	VMCOREINFO_SYMBOL(kallsyms_offsets);
+	VMCOREINFO_SYMBOL(kallsyms_relative_base);
+#else
+	VMCOREINFO_SYMBOL(kallsyms_addresses);
+#endif /* CONFIG_KALLSYMS_BASE_RELATIVE */
+#endif /* CONFIG_KALLSYMS */
+
+	arch_crash_save_vmcoreinfo();
+	update_vmcoreinfo_note();
+
+	return 0;
+}
+
+subsys_initcall(crash_save_vmcoreinfo_init);
diff --git a/kernel/crash_dump.c b/kernel/crash_dump.c
new file mode 100644
index 000000000..92da32275
--- /dev/null
+++ b/kernel/crash_dump.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kernel.h>
+#include <linux/crash_dump.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+
+/*
+ * stores the physical address of elf header of crash image
+ *
+ * Note: elfcorehdr_addr is not just limited to vmcore. It is also used by
+ * is_kdump_kernel() to determine if we are booting after a panic. Hence put
+ * it under CONFIG_CRASH_DUMP and not CONFIG_PROC_VMCORE.
+ */
+unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
+EXPORT_SYMBOL_GPL(elfcorehdr_addr);
+
+/*
+ * stores the size of elf header of crash image
+ */
+unsigned long long elfcorehdr_size;
+
+/*
+ * elfcorehdr= specifies the location of elf core header stored by the crashed
+ * kernel. This option will be passed by kexec loader to the capture kernel.
+ *
+ * Syntax: elfcorehdr=[size[KMG]@]offset[KMG]
+ */
+static int __init setup_elfcorehdr(char *arg)
+{
+	char *end;
+	if (!arg)
+		return -EINVAL;
+	elfcorehdr_addr = memparse(arg, &end);
+	if (*end == '@') {
+		elfcorehdr_size = elfcorehdr_addr;
+		elfcorehdr_addr = memparse(end + 1, &end);
+	}
+	return end > arg ? 0 : -EINVAL;
+}
+early_param("elfcorehdr", setup_elfcorehdr);
diff --git a/kernel/cred.c b/kernel/cred.c
new file mode 100644
index 000000000..d35bc0aa9
--- /dev/null
+++ b/kernel/cred.c
@@ -0,0 +1,927 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Task credentials management - see Documentation/security/credentials.rst
+ *
+ * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+#include <linux/export.h>
+#include <linux/cred.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/sched/coredump.h>
+#include <linux/key.h>
+#include <linux/keyctl.h>
+#include <linux/init_task.h>
+#include <linux/security.h>
+#include <linux/binfmts.h>
+#include <linux/cn_proc.h>
+#include <linux/uidgid.h>
+
+#if 0
+#define kdebug(FMT, ...)						\
+	printk("[%-5.5s%5u] " FMT "\n",					\
+	       current->comm, current->pid, ##__VA_ARGS__)
+#else
+#define kdebug(FMT, ...)						\
+do {									\
+	if (0)								\
+		no_printk("[%-5.5s%5u] " FMT "\n",			\
+			  current->comm, current->pid, ##__VA_ARGS__);	\
+} while (0)
+#endif
+
+static struct kmem_cache *cred_jar;
+
+/* init to 2 - one for init_task, one to ensure it is never freed */
+static struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
+
+/*
+ * The initial credentials for the initial task
+ */
+struct cred init_cred = {
+	.usage			= ATOMIC_INIT(4),
+#ifdef CONFIG_DEBUG_CREDENTIALS
+	.subscribers		= ATOMIC_INIT(2),
+	.magic			= CRED_MAGIC,
+#endif
+	.uid			= GLOBAL_ROOT_UID,
+	.gid			= GLOBAL_ROOT_GID,
+	.suid			= GLOBAL_ROOT_UID,
+	.sgid			= GLOBAL_ROOT_GID,
+	.euid			= GLOBAL_ROOT_UID,
+	.egid			= GLOBAL_ROOT_GID,
+	.fsuid			= GLOBAL_ROOT_UID,
+	.fsgid			= GLOBAL_ROOT_GID,
+	.securebits		= SECUREBITS_DEFAULT,
+	.cap_inheritable	= CAP_EMPTY_SET,
+	.cap_permitted		= CAP_FULL_SET,
+	.cap_effective		= CAP_FULL_SET,
+	.cap_bset		= CAP_FULL_SET,
+	.user			= INIT_USER,
+	.user_ns		= &init_user_ns,
+	.group_info		= &init_groups,
+	.ucounts		= &init_ucounts,
+};
+
+static inline void set_cred_subscribers(struct cred *cred, int n)
+{
+#ifdef CONFIG_DEBUG_CREDENTIALS
+	atomic_set(&cred->subscribers, n);
+#endif
+}
+
+static inline int read_cred_subscribers(const struct cred *cred)
+{
+#ifdef CONFIG_DEBUG_CREDENTIALS
+	return atomic_read(&cred->subscribers);
+#else
+	return 0;
+#endif
+}
+
+static inline void alter_cred_subscribers(const struct cred *_cred, int n)
+{
+#ifdef CONFIG_DEBUG_CREDENTIALS
+	struct cred *cred = (struct cred *) _cred;
+
+	atomic_add(n, &cred->subscribers);
+#endif
+}
+
+/*
+ * The RCU callback to actually dispose of a set of credentials
+ */
+static void put_cred_rcu(struct rcu_head *rcu)
+{
+	struct cred *cred = container_of(rcu, struct cred, rcu);
+
+	kdebug("put_cred_rcu(%p)", cred);
+
+#ifdef CONFIG_DEBUG_CREDENTIALS
+	if (cred->magic != CRED_MAGIC_DEAD ||
+	    atomic_long_read(&cred->usage) != 0 ||
+	    read_cred_subscribers(cred) != 0)
+		panic("CRED: put_cred_rcu() sees %p with"
+		      " mag %x, put %p, usage %ld, subscr %d\n",
+		      cred, cred->magic, cred->put_addr,
+		      atomic_long_read(&cred->usage),
+		      read_cred_subscribers(cred));
+#else
+	if (atomic_long_read(&cred->usage) != 0)
+		panic("CRED: put_cred_rcu() sees %p with usage %ld\n",
+		      cred, atomic_long_read(&cred->usage));
+#endif
+
+	security_cred_free(cred);
+	key_put(cred->session_keyring);
+	key_put(cred->process_keyring);
+	key_put(cred->thread_keyring);
+	key_put(cred->request_key_auth);
+	if (cred->group_info)
+		put_group_info(cred->group_info);
+	free_uid(cred->user);
+	if (cred->ucounts)
+		put_ucounts(cred->ucounts);
+	put_user_ns(cred->user_ns);
+	kmem_cache_free(cred_jar, cred);
+}
+
+/**
+ * __put_cred - Destroy a set of credentials
+ * @cred: The record to release
+ *
+ * Destroy a set of credentials on which no references remain.
+ */
+void __put_cred(struct cred *cred)
+{
+	kdebug("__put_cred(%p{%ld,%d})", cred,
+	       atomic_long_read(&cred->usage),
+	       read_cred_subscribers(cred));
+
+	BUG_ON(atomic_long_read(&cred->usage) != 0);
+#ifdef CONFIG_DEBUG_CREDENTIALS
+	BUG_ON(read_cred_subscribers(cred) != 0);
+	cred->magic = CRED_MAGIC_DEAD;
+	cred->put_addr = __builtin_return_address(0);
+#endif
+	BUG_ON(cred == current->cred);
+	BUG_ON(cred == current->real_cred);
+
+	if (cred->non_rcu)
+		put_cred_rcu(&cred->rcu);
+	else
+		call_rcu(&cred->rcu, put_cred_rcu);
+}
+EXPORT_SYMBOL(__put_cred);
+
+/*
+ * Clean up a task's credentials when it exits
+ */
+void exit_creds(struct task_struct *tsk)
+{
+	struct cred *cred;
+
+	kdebug("exit_creds(%u,%p,%p,{%ld,%d})", tsk->pid, tsk->real_cred, tsk->cred,
+	       atomic_long_read(&tsk->cred->usage),
+	       read_cred_subscribers(tsk->cred));
+
+	cred = (struct cred *) tsk->real_cred;
+	tsk->real_cred = NULL;
+	validate_creds(cred);
+	alter_cred_subscribers(cred, -1);
+	put_cred(cred);
+
+	cred = (struct cred *) tsk->cred;
+	tsk->cred = NULL;
+	validate_creds(cred);
+	alter_cred_subscribers(cred, -1);
+	put_cred(cred);
+
+#ifdef CONFIG_KEYS_REQUEST_CACHE
+	key_put(tsk->cached_requested_key);
+	tsk->cached_requested_key = NULL;
+#endif
+}
+
+/**
+ * get_task_cred - Get another task's objective credentials
+ * @task: The task to query
+ *
+ * Get the objective credentials of a task, pinning them so that they can't go
+ * away.  Accessing a task's credentials directly is not permitted.
+ *
+ * The caller must also make sure task doesn't get deleted, either by holding a
+ * ref on task or by holding tasklist_lock to prevent it from being unlinked.
+ */
+const struct cred *get_task_cred(struct task_struct *task)
+{
+	const struct cred *cred;
+
+	rcu_read_lock();
+
+	do {
+		cred = __task_cred((task));
+		BUG_ON(!cred);
+	} while (!get_cred_rcu(cred));
+
+	rcu_read_unlock();
+	return cred;
+}
+EXPORT_SYMBOL(get_task_cred);
+
+/*
+ * Allocate blank credentials, such that the credentials can be filled in at a
+ * later date without risk of ENOMEM.
+ */
+struct cred *cred_alloc_blank(void)
+{
+	struct cred *new;
+
+	new = kmem_cache_zalloc(cred_jar, GFP_KERNEL);
+	if (!new)
+		return NULL;
+
+	atomic_long_set(&new->usage, 1);
+#ifdef CONFIG_DEBUG_CREDENTIALS
+	new->magic = CRED_MAGIC;
+#endif
+	if (security_cred_alloc_blank(new, GFP_KERNEL_ACCOUNT) < 0)
+		goto error;
+
+	return new;
+
+error:
+	abort_creds(new);
+	return NULL;
+}
+
+/**
+ * prepare_creds - Prepare a new set of credentials for modification
+ *
+ * Prepare a new set of task credentials for modification.  A task's creds
+ * shouldn't generally be modified directly, therefore this function is used to
+ * prepare a new copy, which the caller then modifies and then commits by
+ * calling commit_creds().
+ *
+ * Preparation involves making a copy of the objective creds for modification.
+ *
+ * Returns a pointer to the new creds-to-be if successful, NULL otherwise.
+ *
+ * Call commit_creds() or abort_creds() to clean up.
+ */
+struct cred *prepare_creds(void)
+{
+	struct task_struct *task = current;
+	const struct cred *old;
+	struct cred *new;
+
+	validate_process_creds();
+
+	new = kmem_cache_alloc(cred_jar, GFP_KERNEL);
+	if (!new)
+		return NULL;
+
+	kdebug("prepare_creds() alloc %p", new);
+
+	old = task->cred;
+	memcpy(new, old, sizeof(struct cred));
+
+	new->non_rcu = 0;
+	atomic_long_set(&new->usage, 1);
+	set_cred_subscribers(new, 0);
+	get_group_info(new->group_info);
+	get_uid(new->user);
+	get_user_ns(new->user_ns);
+
+#ifdef CONFIG_KEYS
+	key_get(new->session_keyring);
+	key_get(new->process_keyring);
+	key_get(new->thread_keyring);
+	key_get(new->request_key_auth);
+#endif
+
+#ifdef CONFIG_SECURITY
+	new->security = NULL;
+#endif
+
+	new->ucounts = get_ucounts(new->ucounts);
+	if (!new->ucounts)
+		goto error;
+
+	if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0)
+		goto error;
+
+	validate_creds(new);
+	return new;
+
+error:
+	abort_creds(new);
+	return NULL;
+}
+EXPORT_SYMBOL(prepare_creds);
+
+/*
+ * Prepare credentials for current to perform an execve()
+ * - The caller must hold ->cred_guard_mutex
+ */
+struct cred *prepare_exec_creds(void)
+{
+	struct cred *new;
+
+	new = prepare_creds();
+	if (!new)
+		return new;
+
+#ifdef CONFIG_KEYS
+	/* newly exec'd tasks don't get a thread keyring */
+	key_put(new->thread_keyring);
+	new->thread_keyring = NULL;
+
+	/* inherit the session keyring; new process keyring */
+	key_put(new->process_keyring);
+	new->process_keyring = NULL;
+#endif
+
+	new->suid = new->fsuid = new->euid;
+	new->sgid = new->fsgid = new->egid;
+
+	return new;
+}
+
+/*
+ * Copy credentials for the new process created by fork()
+ *
+ * We share if we can, but under some circumstances we have to generate a new
+ * set.
+ *
+ * The new process gets the current process's subjective credentials as its
+ * objective and subjective credentials
+ */
+int copy_creds(struct task_struct *p, unsigned long clone_flags)
+{
+	struct cred *new;
+	int ret;
+
+#ifdef CONFIG_KEYS_REQUEST_CACHE
+	p->cached_requested_key = NULL;
+#endif
+
+	if (
+#ifdef CONFIG_KEYS
+		!p->cred->thread_keyring &&
+#endif
+		clone_flags & CLONE_THREAD
+	    ) {
+		p->real_cred = get_cred(p->cred);
+		get_cred(p->cred);
+		alter_cred_subscribers(p->cred, 2);
+		kdebug("share_creds(%p{%ld,%d})",
+		       p->cred, atomic_long_read(&p->cred->usage),
+		       read_cred_subscribers(p->cred));
+		inc_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
+		return 0;
+	}
+
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+
+	if (clone_flags & CLONE_NEWUSER) {
+		ret = create_user_ns(new);
+		if (ret < 0)
+			goto error_put;
+		ret = set_cred_ucounts(new);
+		if (ret < 0)
+			goto error_put;
+	}
+
+#ifdef CONFIG_KEYS
+	/* new threads get their own thread keyrings if their parent already
+	 * had one */
+	if (new->thread_keyring) {
+		key_put(new->thread_keyring);
+		new->thread_keyring = NULL;
+		if (clone_flags & CLONE_THREAD)
+			install_thread_keyring_to_cred(new);
+	}
+
+	/* The process keyring is only shared between the threads in a process;
+	 * anything outside of those threads doesn't inherit.
+	 */
+	if (!(clone_flags & CLONE_THREAD)) {
+		key_put(new->process_keyring);
+		new->process_keyring = NULL;
+	}
+#endif
+
+	p->cred = p->real_cred = get_cred(new);
+	inc_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
+	alter_cred_subscribers(new, 2);
+	validate_creds(new);
+	return 0;
+
+error_put:
+	put_cred(new);
+	return ret;
+}
+
+static bool cred_cap_issubset(const struct cred *set, const struct cred *subset)
+{
+	const struct user_namespace *set_ns = set->user_ns;
+	const struct user_namespace *subset_ns = subset->user_ns;
+
+	/* If the two credentials are in the same user namespace see if
+	 * the capabilities of subset are a subset of set.
+	 */
+	if (set_ns == subset_ns)
+		return cap_issubset(subset->cap_permitted, set->cap_permitted);
+
+	/* The credentials are in a different user namespaces
+	 * therefore one is a subset of the other only if a set is an
+	 * ancestor of subset and set->euid is owner of subset or one
+	 * of subsets ancestors.
+	 */
+	for (;subset_ns != &init_user_ns; subset_ns = subset_ns->parent) {
+		if ((set_ns == subset_ns->parent)  &&
+		    uid_eq(subset_ns->owner, set->euid))
+			return true;
+	}
+
+	return false;
+}
+
+/**
+ * commit_creds - Install new credentials upon the current task
+ * @new: The credentials to be assigned
+ *
+ * Install a new set of credentials to the current task, using RCU to replace
+ * the old set.  Both the objective and the subjective credentials pointers are
+ * updated.  This function may not be called if the subjective credentials are
+ * in an overridden state.
+ *
+ * This function eats the caller's reference to the new credentials.
+ *
+ * Always returns 0 thus allowing this function to be tail-called at the end
+ * of, say, sys_setgid().
+ */
+int commit_creds(struct cred *new)
+{
+	struct task_struct *task = current;
+	const struct cred *old = task->real_cred;
+
+	kdebug("commit_creds(%p{%ld,%d})", new,
+	       atomic_long_read(&new->usage),
+	       read_cred_subscribers(new));
+
+	BUG_ON(task->cred != old);
+#ifdef CONFIG_DEBUG_CREDENTIALS
+	BUG_ON(read_cred_subscribers(old) < 2);
+	validate_creds(old);
+	validate_creds(new);
+#endif
+	BUG_ON(atomic_long_read(&new->usage) < 1);
+
+	get_cred(new); /* we will require a ref for the subj creds too */
+
+	/* dumpability changes */
+	if (!uid_eq(old->euid, new->euid) ||
+	    !gid_eq(old->egid, new->egid) ||
+	    !uid_eq(old->fsuid, new->fsuid) ||
+	    !gid_eq(old->fsgid, new->fsgid) ||
+	    !cred_cap_issubset(old, new)) {
+		if (task->mm)
+			set_dumpable(task->mm, suid_dumpable);
+		task->pdeath_signal = 0;
+		/*
+		 * If a task drops privileges and becomes nondumpable,
+		 * the dumpability change must become visible before
+		 * the credential change; otherwise, a __ptrace_may_access()
+		 * racing with this change may be able to attach to a task it
+		 * shouldn't be able to attach to (as if the task had dropped
+		 * privileges without becoming nondumpable).
+		 * Pairs with a read barrier in __ptrace_may_access().
+		 */
+		smp_wmb();
+	}
+
+	/* alter the thread keyring */
+	if (!uid_eq(new->fsuid, old->fsuid))
+		key_fsuid_changed(new);
+	if (!gid_eq(new->fsgid, old->fsgid))
+		key_fsgid_changed(new);
+
+	/* do it
+	 * RLIMIT_NPROC limits on user->processes have already been checked
+	 * in set_user().
+	 */
+	alter_cred_subscribers(new, 2);
+	if (new->user != old->user || new->user_ns != old->user_ns)
+		inc_rlimit_ucounts(new->ucounts, UCOUNT_RLIMIT_NPROC, 1);
+	rcu_assign_pointer(task->real_cred, new);
+	rcu_assign_pointer(task->cred, new);
+	if (new->user != old->user || new->user_ns != old->user_ns)
+		dec_rlimit_ucounts(old->ucounts, UCOUNT_RLIMIT_NPROC, 1);
+	alter_cred_subscribers(old, -2);
+
+	/* send notifications */
+	if (!uid_eq(new->uid,   old->uid)  ||
+	    !uid_eq(new->euid,  old->euid) ||
+	    !uid_eq(new->suid,  old->suid) ||
+	    !uid_eq(new->fsuid, old->fsuid))
+		proc_id_connector(task, PROC_EVENT_UID);
+
+	if (!gid_eq(new->gid,   old->gid)  ||
+	    !gid_eq(new->egid,  old->egid) ||
+	    !gid_eq(new->sgid,  old->sgid) ||
+	    !gid_eq(new->fsgid, old->fsgid))
+		proc_id_connector(task, PROC_EVENT_GID);
+
+	/* release the old obj and subj refs both */
+	put_cred(old);
+	put_cred(old);
+	return 0;
+}
+EXPORT_SYMBOL(commit_creds);
+
+/**
+ * abort_creds - Discard a set of credentials and unlock the current task
+ * @new: The credentials that were going to be applied
+ *
+ * Discard a set of credentials that were under construction and unlock the
+ * current task.
+ */
+void abort_creds(struct cred *new)
+{
+	kdebug("abort_creds(%p{%ld,%d})", new,
+	       atomic_long_read(&new->usage),
+	       read_cred_subscribers(new));
+
+#ifdef CONFIG_DEBUG_CREDENTIALS
+	BUG_ON(read_cred_subscribers(new) != 0);
+#endif
+	BUG_ON(atomic_long_read(&new->usage) < 1);
+	put_cred(new);
+}
+EXPORT_SYMBOL(abort_creds);
+
+/**
+ * override_creds - Override the current process's subjective credentials
+ * @new: The credentials to be assigned
+ *
+ * Install a set of temporary override subjective credentials on the current
+ * process, returning the old set for later reversion.
+ */
+const struct cred *override_creds(const struct cred *new)
+{
+	const struct cred *old = current->cred;
+
+	kdebug("override_creds(%p{%ld,%d})", new,
+	       atomic_long_read(&new->usage),
+	       read_cred_subscribers(new));
+
+	validate_creds(old);
+	validate_creds(new);
+
+	/*
+	 * NOTE! This uses 'get_new_cred()' rather than 'get_cred()'.
+	 *
+	 * That means that we do not clear the 'non_rcu' flag, since
+	 * we are only installing the cred into the thread-synchronous
+	 * '->cred' pointer, not the '->real_cred' pointer that is
+	 * visible to other threads under RCU.
+	 *
+	 * Also note that we did validate_creds() manually, not depending
+	 * on the validation in 'get_cred()'.
+	 */
+	get_new_cred((struct cred *)new);
+	alter_cred_subscribers(new, 1);
+	rcu_assign_pointer(current->cred, new);
+	alter_cred_subscribers(old, -1);
+
+	kdebug("override_creds() = %p{%ld,%d}", old,
+	       atomic_long_read(&old->usage),
+	       read_cred_subscribers(old));
+	return old;
+}
+EXPORT_SYMBOL(override_creds);
+
+/**
+ * revert_creds - Revert a temporary subjective credentials override
+ * @old: The credentials to be restored
+ *
+ * Revert a temporary set of override subjective credentials to an old set,
+ * discarding the override set.
+ */
+void revert_creds(const struct cred *old)
+{
+	const struct cred *override = current->cred;
+
+	kdebug("revert_creds(%p{%ld,%d})", old,
+	       atomic_long_read(&old->usage),
+	       read_cred_subscribers(old));
+
+	validate_creds(old);
+	validate_creds(override);
+	alter_cred_subscribers(old, 1);
+	rcu_assign_pointer(current->cred, old);
+	alter_cred_subscribers(override, -1);
+	put_cred(override);
+}
+EXPORT_SYMBOL(revert_creds);
+
+/**
+ * cred_fscmp - Compare two credentials with respect to filesystem access.
+ * @a: The first credential
+ * @b: The second credential
+ *
+ * cred_cmp() will return zero if both credentials have the same
+ * fsuid, fsgid, and supplementary groups.  That is, if they will both
+ * provide the same access to files based on mode/uid/gid.
+ * If the credentials are different, then either -1 or 1 will
+ * be returned depending on whether @a comes before or after @b
+ * respectively in an arbitrary, but stable, ordering of credentials.
+ *
+ * Return: -1, 0, or 1 depending on comparison
+ */
+int cred_fscmp(const struct cred *a, const struct cred *b)
+{
+	struct group_info *ga, *gb;
+	int g;
+
+	if (a == b)
+		return 0;
+	if (uid_lt(a->fsuid, b->fsuid))
+		return -1;
+	if (uid_gt(a->fsuid, b->fsuid))
+		return 1;
+
+	if (gid_lt(a->fsgid, b->fsgid))
+		return -1;
+	if (gid_gt(a->fsgid, b->fsgid))
+		return 1;
+
+	ga = a->group_info;
+	gb = b->group_info;
+	if (ga == gb)
+		return 0;
+	if (ga == NULL)
+		return -1;
+	if (gb == NULL)
+		return 1;
+	if (ga->ngroups < gb->ngroups)
+		return -1;
+	if (ga->ngroups > gb->ngroups)
+		return 1;
+
+	for (g = 0; g < ga->ngroups; g++) {
+		if (gid_lt(ga->gid[g], gb->gid[g]))
+			return -1;
+		if (gid_gt(ga->gid[g], gb->gid[g]))
+			return 1;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(cred_fscmp);
+
+int set_cred_ucounts(struct cred *new)
+{
+	struct ucounts *new_ucounts, *old_ucounts = new->ucounts;
+
+	/*
+	 * This optimization is needed because alloc_ucounts() uses locks
+	 * for table lookups.
+	 */
+	if (old_ucounts->ns == new->user_ns && uid_eq(old_ucounts->uid, new->uid))
+		return 0;
+
+	if (!(new_ucounts = alloc_ucounts(new->user_ns, new->uid)))
+		return -EAGAIN;
+
+	new->ucounts = new_ucounts;
+	put_ucounts(old_ucounts);
+
+	return 0;
+}
+
+/*
+ * initialise the credentials stuff
+ */
+void __init cred_init(void)
+{
+	/* allocate a slab in which we can store credentials */
+	cred_jar = kmem_cache_create("cred_jar", sizeof(struct cred), 0,
+			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL);
+}
+
+/**
+ * prepare_kernel_cred - Prepare a set of credentials for a kernel service
+ * @daemon: A userspace daemon to be used as a reference
+ *
+ * Prepare a set of credentials for a kernel service.  This can then be used to
+ * override a task's own credentials so that work can be done on behalf of that
+ * task that requires a different subjective context.
+ *
+ * @daemon is used to provide a base for the security record, but can be NULL.
+ * If @daemon is supplied, then the security data will be derived from that;
+ * otherwise they'll be set to 0 and no groups, full capabilities and no keys.
+ *
+ * The caller may change these controls afterwards if desired.
+ *
+ * Returns the new credentials or NULL if out of memory.
+ */
+struct cred *prepare_kernel_cred(struct task_struct *daemon)
+{
+	const struct cred *old;
+	struct cred *new;
+
+	new = kmem_cache_alloc(cred_jar, GFP_KERNEL);
+	if (!new)
+		return NULL;
+
+	kdebug("prepare_kernel_cred() alloc %p", new);
+
+	if (daemon)
+		old = get_task_cred(daemon);
+	else
+		old = get_cred(&init_cred);
+
+	validate_creds(old);
+
+	*new = *old;
+	new->non_rcu = 0;
+	atomic_long_set(&new->usage, 1);
+	set_cred_subscribers(new, 0);
+	get_uid(new->user);
+	get_user_ns(new->user_ns);
+	get_group_info(new->group_info);
+
+#ifdef CONFIG_KEYS
+	new->session_keyring = NULL;
+	new->process_keyring = NULL;
+	new->thread_keyring = NULL;
+	new->request_key_auth = NULL;
+	new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
+#endif
+
+#ifdef CONFIG_SECURITY
+	new->security = NULL;
+#endif
+	new->ucounts = get_ucounts(new->ucounts);
+	if (!new->ucounts)
+		goto error;
+
+	if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0)
+		goto error;
+
+	put_cred(old);
+	validate_creds(new);
+	return new;
+
+error:
+	put_cred(new);
+	put_cred(old);
+	return NULL;
+}
+EXPORT_SYMBOL(prepare_kernel_cred);
+
+/**
+ * set_security_override - Set the security ID in a set of credentials
+ * @new: The credentials to alter
+ * @secid: The LSM security ID to set
+ *
+ * Set the LSM security ID in a set of credentials so that the subjective
+ * security is overridden when an alternative set of credentials is used.
+ */
+int set_security_override(struct cred *new, u32 secid)
+{
+	return security_kernel_act_as(new, secid);
+}
+EXPORT_SYMBOL(set_security_override);
+
+/**
+ * set_security_override_from_ctx - Set the security ID in a set of credentials
+ * @new: The credentials to alter
+ * @secctx: The LSM security context to generate the security ID from.
+ *
+ * Set the LSM security ID in a set of credentials so that the subjective
+ * security is overridden when an alternative set of credentials is used.  The
+ * security ID is specified in string form as a security context to be
+ * interpreted by the LSM.
+ */
+int set_security_override_from_ctx(struct cred *new, const char *secctx)
+{
+	u32 secid;
+	int ret;
+
+	ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
+	if (ret < 0)
+		return ret;
+
+	return set_security_override(new, secid);
+}
+EXPORT_SYMBOL(set_security_override_from_ctx);
+
+/**
+ * set_create_files_as - Set the LSM file create context in a set of credentials
+ * @new: The credentials to alter
+ * @inode: The inode to take the context from
+ *
+ * Change the LSM file creation context in a set of credentials to be the same
+ * as the object context of the specified inode, so that the new inodes have
+ * the same MAC context as that inode.
+ */
+int set_create_files_as(struct cred *new, struct inode *inode)
+{
+	if (!uid_valid(inode->i_uid) || !gid_valid(inode->i_gid))
+		return -EINVAL;
+	new->fsuid = inode->i_uid;
+	new->fsgid = inode->i_gid;
+	return security_kernel_create_files_as(new, inode);
+}
+EXPORT_SYMBOL(set_create_files_as);
+
+#ifdef CONFIG_DEBUG_CREDENTIALS
+
+bool creds_are_invalid(const struct cred *cred)
+{
+	if (cred->magic != CRED_MAGIC)
+		return true;
+	return false;
+}
+EXPORT_SYMBOL(creds_are_invalid);
+
+/*
+ * dump invalid credentials
+ */
+static void dump_invalid_creds(const struct cred *cred, const char *label,
+			       const struct task_struct *tsk)
+{
+	printk(KERN_ERR "CRED: %s credentials: %p %s%s%s\n",
+	       label, cred,
+	       cred == &init_cred ? "[init]" : "",
+	       cred == tsk->real_cred ? "[real]" : "",
+	       cred == tsk->cred ? "[eff]" : "");
+	printk(KERN_ERR "CRED: ->magic=%x, put_addr=%p\n",
+	       cred->magic, cred->put_addr);
+	printk(KERN_ERR "CRED: ->usage=%ld, subscr=%d\n",
+	       atomic_long_read(&cred->usage),
+	       read_cred_subscribers(cred));
+	printk(KERN_ERR "CRED: ->*uid = { %d,%d,%d,%d }\n",
+		from_kuid_munged(&init_user_ns, cred->uid),
+		from_kuid_munged(&init_user_ns, cred->euid),
+		from_kuid_munged(&init_user_ns, cred->suid),
+		from_kuid_munged(&init_user_ns, cred->fsuid));
+	printk(KERN_ERR "CRED: ->*gid = { %d,%d,%d,%d }\n",
+		from_kgid_munged(&init_user_ns, cred->gid),
+		from_kgid_munged(&init_user_ns, cred->egid),
+		from_kgid_munged(&init_user_ns, cred->sgid),
+		from_kgid_munged(&init_user_ns, cred->fsgid));
+#ifdef CONFIG_SECURITY
+	printk(KERN_ERR "CRED: ->security is %p\n", cred->security);
+	if ((unsigned long) cred->security >= PAGE_SIZE &&
+	    (((unsigned long) cred->security & 0xffffff00) !=
+	     (POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8)))
+		printk(KERN_ERR "CRED: ->security {%x, %x}\n",
+		       ((u32*)cred->security)[0],
+		       ((u32*)cred->security)[1]);
+#endif
+}
+
+/*
+ * report use of invalid credentials
+ */
+void __noreturn __invalid_creds(const struct cred *cred, const char *file, unsigned line)
+{
+	printk(KERN_ERR "CRED: Invalid credentials\n");
+	printk(KERN_ERR "CRED: At %s:%u\n", file, line);
+	dump_invalid_creds(cred, "Specified", current);
+	BUG();
+}
+EXPORT_SYMBOL(__invalid_creds);
+
+/*
+ * check the credentials on a process
+ */
+void __validate_process_creds(struct task_struct *tsk,
+			      const char *file, unsigned line)
+{
+	if (tsk->cred == tsk->real_cred) {
+		if (unlikely(read_cred_subscribers(tsk->cred) < 2 ||
+			     creds_are_invalid(tsk->cred)))
+			goto invalid_creds;
+	} else {
+		if (unlikely(read_cred_subscribers(tsk->real_cred) < 1 ||
+			     read_cred_subscribers(tsk->cred) < 1 ||
+			     creds_are_invalid(tsk->real_cred) ||
+			     creds_are_invalid(tsk->cred)))
+			goto invalid_creds;
+	}
+	return;
+
+invalid_creds:
+	printk(KERN_ERR "CRED: Invalid process credentials\n");
+	printk(KERN_ERR "CRED: At %s:%u\n", file, line);
+
+	dump_invalid_creds(tsk->real_cred, "Real", tsk);
+	if (tsk->cred != tsk->real_cred)
+		dump_invalid_creds(tsk->cred, "Effective", tsk);
+	else
+		printk(KERN_ERR "CRED: Effective creds == Real creds\n");
+	BUG();
+}
+EXPORT_SYMBOL(__validate_process_creds);
+
+/*
+ * check creds for do_exit()
+ */
+void validate_creds_for_do_exit(struct task_struct *tsk)
+{
+	kdebug("validate_creds_for_do_exit(%p,%p{%ld,%d})",
+	       tsk->real_cred, tsk->cred,
+	       atomic_long_read(&tsk->cred->usage),
+	       read_cred_subscribers(tsk->cred));
+
+	__validate_process_creds(tsk, __FILE__, __LINE__);
+}
+
+#endif /* CONFIG_DEBUG_CREDENTIALS */
diff --git a/kernel/debug/Makefile b/kernel/debug/Makefile
new file mode 100644
index 000000000..332ee6c6e
--- /dev/null
+++ b/kernel/debug/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for the linux kernel debugger
+#
+
+obj-$(CONFIG_KGDB) += debug_core.o gdbstub.o
+obj-$(CONFIG_KGDB_KDB) += kdb/
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
new file mode 100644
index 000000000..3a904d869
--- /dev/null
+++ b/kernel/debug/debug_core.c
@@ -0,0 +1,1239 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Kernel Debug Core
+ *
+ * Maintainer: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002-2004 Timesys Corporation
+ * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com>
+ * Copyright (C) 2004 Pavel Machek <pavel@ucw.cz>
+ * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org>
+ * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
+ * Copyright (C) 2005-2009 Wind River Systems, Inc.
+ * Copyright (C) 2007 MontaVista Software, Inc.
+ * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * Contributors at various stages not listed above:
+ *  Jason Wessel ( jason.wessel@windriver.com )
+ *  George Anzinger <george@mvista.com>
+ *  Anurekh Saxena (anurekh.saxena@timesys.com)
+ *  Lake Stevens Instrument Division (Glenn Engel)
+ *  Jim Kingdon, Cygnus Support.
+ *
+ * Original KGDB stub: David Grothe <dave@gcom.com>,
+ * Tigran Aivazian <tigran@sco.com>
+ */
+
+#define pr_fmt(fmt) "KGDB: " fmt
+
+#include <linux/pid_namespace.h>
+#include <linux/clocksource.h>
+#include <linux/serial_core.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/console.h>
+#include <linux/threads.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/sysrq.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+#include <linux/nmi.h>
+#include <linux/pid.h>
+#include <linux/smp.h>
+#include <linux/mm.h>
+#include <linux/rcupdate.h>
+#include <linux/irq.h>
+#include <linux/security.h>
+
+#include <asm/cacheflush.h>
+#include <asm/byteorder.h>
+#include <linux/atomic.h>
+
+#include "debug_core.h"
+
+static int kgdb_break_asap;
+
+struct debuggerinfo_struct kgdb_info[NR_CPUS];
+
+/* kgdb_connected - Is a host GDB connected to us? */
+int				kgdb_connected;
+EXPORT_SYMBOL_GPL(kgdb_connected);
+
+/* All the KGDB handlers are installed */
+int			kgdb_io_module_registered;
+
+/* Guard for recursive entry */
+static int			exception_level;
+
+struct kgdb_io		*dbg_io_ops;
+static DEFINE_SPINLOCK(kgdb_registration_lock);
+
+/* Action for the reboot notifier, a global allow kdb to change it */
+static int kgdbreboot;
+/* kgdb console driver is loaded */
+static int kgdb_con_registered;
+/* determine if kgdb console output should be used */
+static int kgdb_use_con;
+/* Flag for alternate operations for early debugging */
+bool dbg_is_early = true;
+/* Next cpu to become the master debug core */
+int dbg_switch_cpu;
+
+/* Use kdb or gdbserver mode */
+int dbg_kdb_mode = 1;
+
+module_param(kgdb_use_con, int, 0644);
+module_param(kgdbreboot, int, 0644);
+
+/*
+ * Holds information about breakpoints in a kernel. These breakpoints are
+ * added and removed by gdb.
+ */
+static struct kgdb_bkpt		kgdb_break[KGDB_MAX_BREAKPOINTS] = {
+	[0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
+};
+
+/*
+ * The CPU# of the active CPU, or -1 if none:
+ */
+atomic_t			kgdb_active = ATOMIC_INIT(-1);
+EXPORT_SYMBOL_GPL(kgdb_active);
+static DEFINE_RAW_SPINLOCK(dbg_master_lock);
+static DEFINE_RAW_SPINLOCK(dbg_slave_lock);
+
+/*
+ * We use NR_CPUs not PERCPU, in case kgdb is used to debug early
+ * bootup code (which might not have percpu set up yet):
+ */
+static atomic_t			masters_in_kgdb;
+static atomic_t			slaves_in_kgdb;
+atomic_t			kgdb_setting_breakpoint;
+
+struct task_struct		*kgdb_usethread;
+struct task_struct		*kgdb_contthread;
+
+int				kgdb_single_step;
+static pid_t			kgdb_sstep_pid;
+
+/* to keep track of the CPU which is doing the single stepping*/
+atomic_t			kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
+
+/*
+ * If you are debugging a problem where roundup (the collection of
+ * all other CPUs) is a problem [this should be extremely rare],
+ * then use the nokgdbroundup option to avoid roundup. In that case
+ * the other CPUs might interfere with your debugging context, so
+ * use this with care:
+ */
+static int kgdb_do_roundup = 1;
+
+static int __init opt_nokgdbroundup(char *str)
+{
+	kgdb_do_roundup = 0;
+
+	return 0;
+}
+
+early_param("nokgdbroundup", opt_nokgdbroundup);
+
+/*
+ * Finally, some KGDB code :-)
+ */
+
+/*
+ * Weak aliases for breakpoint management,
+ * can be overridden by architectures when needed:
+ */
+int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
+{
+	int err;
+
+	err = copy_from_kernel_nofault(bpt->saved_instr, (char *)bpt->bpt_addr,
+				BREAK_INSTR_SIZE);
+	if (err)
+		return err;
+	err = copy_to_kernel_nofault((char *)bpt->bpt_addr,
+				 arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
+	return err;
+}
+NOKPROBE_SYMBOL(kgdb_arch_set_breakpoint);
+
+int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
+{
+	return copy_to_kernel_nofault((char *)bpt->bpt_addr,
+				  (char *)bpt->saved_instr, BREAK_INSTR_SIZE);
+}
+NOKPROBE_SYMBOL(kgdb_arch_remove_breakpoint);
+
+int __weak kgdb_validate_break_address(unsigned long addr)
+{
+	struct kgdb_bkpt tmp;
+	int err;
+
+	if (kgdb_within_blocklist(addr))
+		return -EINVAL;
+
+	/* Validate setting the breakpoint and then removing it.  If the
+	 * remove fails, the kernel needs to emit a bad message because we
+	 * are deep trouble not being able to put things back the way we
+	 * found them.
+	 */
+	tmp.bpt_addr = addr;
+	err = kgdb_arch_set_breakpoint(&tmp);
+	if (err)
+		return err;
+	err = kgdb_arch_remove_breakpoint(&tmp);
+	if (err)
+		pr_err("Critical breakpoint error, kernel memory destroyed at: %lx\n",
+		       addr);
+	return err;
+}
+
+unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+	return instruction_pointer(regs);
+}
+NOKPROBE_SYMBOL(kgdb_arch_pc);
+
+int __weak kgdb_arch_init(void)
+{
+	return 0;
+}
+
+int __weak kgdb_skipexception(int exception, struct pt_regs *regs)
+{
+	return 0;
+}
+NOKPROBE_SYMBOL(kgdb_skipexception);
+
+#ifdef CONFIG_SMP
+
+/*
+ * Default (weak) implementation for kgdb_roundup_cpus
+ */
+
+void __weak kgdb_call_nmi_hook(void *ignored)
+{
+	/*
+	 * NOTE: get_irq_regs() is supposed to get the registers from
+	 * before the IPI interrupt happened and so is supposed to
+	 * show where the processor was.  In some situations it's
+	 * possible we might be called without an IPI, so it might be
+	 * safer to figure out how to make kgdb_breakpoint() work
+	 * properly here.
+	 */
+	kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
+}
+NOKPROBE_SYMBOL(kgdb_call_nmi_hook);
+
+static DEFINE_PER_CPU(call_single_data_t, kgdb_roundup_csd) =
+	CSD_INIT(kgdb_call_nmi_hook, NULL);
+
+void __weak kgdb_roundup_cpus(void)
+{
+	call_single_data_t *csd;
+	int this_cpu = raw_smp_processor_id();
+	int cpu;
+	int ret;
+
+	for_each_online_cpu(cpu) {
+		/* No need to roundup ourselves */
+		if (cpu == this_cpu)
+			continue;
+
+		csd = &per_cpu(kgdb_roundup_csd, cpu);
+
+		/*
+		 * If it didn't round up last time, don't try again
+		 * since smp_call_function_single_async() will block.
+		 *
+		 * If rounding_up is false then we know that the
+		 * previous call must have at least started and that
+		 * means smp_call_function_single_async() won't block.
+		 */
+		if (kgdb_info[cpu].rounding_up)
+			continue;
+		kgdb_info[cpu].rounding_up = true;
+
+		ret = smp_call_function_single_async(cpu, csd);
+		if (ret)
+			kgdb_info[cpu].rounding_up = false;
+	}
+}
+NOKPROBE_SYMBOL(kgdb_roundup_cpus);
+
+#endif
+
+/*
+ * Some architectures need cache flushes when we set/clear a
+ * breakpoint:
+ */
+static void kgdb_flush_swbreak_addr(unsigned long addr)
+{
+	if (!CACHE_FLUSH_IS_SAFE)
+		return;
+
+	/* Force flush instruction cache if it was outside the mm */
+	flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
+}
+NOKPROBE_SYMBOL(kgdb_flush_swbreak_addr);
+
+/*
+ * SW breakpoint management:
+ */
+int dbg_activate_sw_breakpoints(void)
+{
+	int error;
+	int ret = 0;
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_SET)
+			continue;
+
+		error = kgdb_arch_set_breakpoint(&kgdb_break[i]);
+		if (error) {
+			ret = error;
+			pr_info("BP install failed: %lx\n",
+				kgdb_break[i].bpt_addr);
+			continue;
+		}
+
+		kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
+		kgdb_break[i].state = BP_ACTIVE;
+	}
+	return ret;
+}
+NOKPROBE_SYMBOL(dbg_activate_sw_breakpoints);
+
+int dbg_set_sw_break(unsigned long addr)
+{
+	int err = kgdb_validate_break_address(addr);
+	int breakno = -1;
+	int i;
+
+	if (err)
+		return err;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_SET) &&
+					(kgdb_break[i].bpt_addr == addr))
+			return -EEXIST;
+	}
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state == BP_REMOVED &&
+					kgdb_break[i].bpt_addr == addr) {
+			breakno = i;
+			break;
+		}
+	}
+
+	if (breakno == -1) {
+		for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+			if (kgdb_break[i].state == BP_UNDEFINED) {
+				breakno = i;
+				break;
+			}
+		}
+	}
+
+	if (breakno == -1)
+		return -E2BIG;
+
+	kgdb_break[breakno].state = BP_SET;
+	kgdb_break[breakno].type = BP_BREAKPOINT;
+	kgdb_break[breakno].bpt_addr = addr;
+
+	return 0;
+}
+
+int dbg_deactivate_sw_breakpoints(void)
+{
+	int error;
+	int ret = 0;
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_ACTIVE)
+			continue;
+		error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
+		if (error) {
+			pr_info("BP remove failed: %lx\n",
+				kgdb_break[i].bpt_addr);
+			ret = error;
+		}
+
+		kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
+		kgdb_break[i].state = BP_SET;
+	}
+	return ret;
+}
+NOKPROBE_SYMBOL(dbg_deactivate_sw_breakpoints);
+
+int dbg_remove_sw_break(unsigned long addr)
+{
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_SET) &&
+				(kgdb_break[i].bpt_addr == addr)) {
+			kgdb_break[i].state = BP_REMOVED;
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+
+int kgdb_isremovedbreak(unsigned long addr)
+{
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_REMOVED) &&
+					(kgdb_break[i].bpt_addr == addr))
+			return 1;
+	}
+	return 0;
+}
+
+int kgdb_has_hit_break(unsigned long addr)
+{
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state == BP_ACTIVE &&
+		    kgdb_break[i].bpt_addr == addr)
+			return 1;
+	}
+	return 0;
+}
+
+int dbg_remove_all_break(void)
+{
+	int error;
+	int i;
+
+	/* Clear memory breakpoints. */
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_ACTIVE)
+			goto setundefined;
+		error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
+		if (error)
+			pr_err("breakpoint remove failed: %lx\n",
+			       kgdb_break[i].bpt_addr);
+setundefined:
+		kgdb_break[i].state = BP_UNDEFINED;
+	}
+
+	/* Clear hardware breakpoints. */
+	if (arch_kgdb_ops.remove_all_hw_break)
+		arch_kgdb_ops.remove_all_hw_break();
+
+	return 0;
+}
+
+void kgdb_free_init_mem(void)
+{
+	int i;
+
+	/* Clear init memory breakpoints. */
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (init_section_contains((void *)kgdb_break[i].bpt_addr, 0))
+			kgdb_break[i].state = BP_UNDEFINED;
+	}
+}
+
+#ifdef CONFIG_KGDB_KDB
+void kdb_dump_stack_on_cpu(int cpu)
+{
+	if (cpu == raw_smp_processor_id() || !IS_ENABLED(CONFIG_SMP)) {
+		dump_stack();
+		return;
+	}
+
+	if (!(kgdb_info[cpu].exception_state & DCPU_IS_SLAVE)) {
+		kdb_printf("ERROR: Task on cpu %d didn't stop in the debugger\n",
+			   cpu);
+		return;
+	}
+
+	/*
+	 * In general, architectures don't support dumping the stack of a
+	 * "running" process that's not the current one.  From the point of
+	 * view of the Linux, kernel processes that are looping in the kgdb
+	 * slave loop are still "running".  There's also no API (that actually
+	 * works across all architectures) that can do a stack crawl based
+	 * on registers passed as a parameter.
+	 *
+	 * Solve this conundrum by asking slave CPUs to do the backtrace
+	 * themselves.
+	 */
+	kgdb_info[cpu].exception_state |= DCPU_WANT_BT;
+	while (kgdb_info[cpu].exception_state & DCPU_WANT_BT)
+		cpu_relax();
+}
+#endif
+
+/*
+ * Return true if there is a valid kgdb I/O module.  Also if no
+ * debugger is attached a message can be printed to the console about
+ * waiting for the debugger to attach.
+ *
+ * The print_wait argument is only to be true when called from inside
+ * the core kgdb_handle_exception, because it will wait for the
+ * debugger to attach.
+ */
+static int kgdb_io_ready(int print_wait)
+{
+	if (!dbg_io_ops)
+		return 0;
+	if (kgdb_connected)
+		return 1;
+	if (atomic_read(&kgdb_setting_breakpoint))
+		return 1;
+	if (print_wait) {
+#ifdef CONFIG_KGDB_KDB
+		if (!dbg_kdb_mode)
+			pr_crit("waiting... or $3#33 for KDB\n");
+#else
+		pr_crit("Waiting for remote debugger\n");
+#endif
+	}
+	return 1;
+}
+NOKPROBE_SYMBOL(kgdb_io_ready);
+
+static int kgdb_reenter_check(struct kgdb_state *ks)
+{
+	unsigned long addr;
+
+	if (atomic_read(&kgdb_active) != raw_smp_processor_id())
+		return 0;
+
+	/* Panic on recursive debugger calls: */
+	exception_level++;
+	addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
+	dbg_deactivate_sw_breakpoints();
+
+	/*
+	 * If the break point removed ok at the place exception
+	 * occurred, try to recover and print a warning to the end
+	 * user because the user planted a breakpoint in a place that
+	 * KGDB needs in order to function.
+	 */
+	if (dbg_remove_sw_break(addr) == 0) {
+		exception_level = 0;
+		kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+		dbg_activate_sw_breakpoints();
+		pr_crit("re-enter error: breakpoint removed %lx\n", addr);
+		WARN_ON_ONCE(1);
+
+		return 1;
+	}
+	dbg_remove_all_break();
+	kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+
+	if (exception_level > 1) {
+		dump_stack();
+		kgdb_io_module_registered = false;
+		panic("Recursive entry to debugger");
+	}
+
+	pr_crit("re-enter exception: ALL breakpoints killed\n");
+#ifdef CONFIG_KGDB_KDB
+	/* Allow kdb to debug itself one level */
+	return 0;
+#endif
+	dump_stack();
+	panic("Recursive entry to debugger");
+
+	return 1;
+}
+NOKPROBE_SYMBOL(kgdb_reenter_check);
+
+static void dbg_touch_watchdogs(void)
+{
+	touch_softlockup_watchdog_sync();
+	clocksource_touch_watchdog();
+	rcu_cpu_stall_reset();
+}
+NOKPROBE_SYMBOL(dbg_touch_watchdogs);
+
+static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs,
+		int exception_state)
+{
+	unsigned long flags;
+	int sstep_tries = 100;
+	int error;
+	int cpu;
+	int trace_on = 0;
+	int online_cpus = num_online_cpus();
+	u64 time_left;
+
+	kgdb_info[ks->cpu].enter_kgdb++;
+	kgdb_info[ks->cpu].exception_state |= exception_state;
+
+	if (exception_state == DCPU_WANT_MASTER)
+		atomic_inc(&masters_in_kgdb);
+	else
+		atomic_inc(&slaves_in_kgdb);
+
+	if (arch_kgdb_ops.disable_hw_break)
+		arch_kgdb_ops.disable_hw_break(regs);
+
+acquirelock:
+	rcu_read_lock();
+	/*
+	 * Interrupts will be restored by the 'trap return' code, except when
+	 * single stepping.
+	 */
+	local_irq_save(flags);
+
+	cpu = ks->cpu;
+	kgdb_info[cpu].debuggerinfo = regs;
+	kgdb_info[cpu].task = current;
+	kgdb_info[cpu].ret_state = 0;
+	kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT;
+
+	/* Make sure the above info reaches the primary CPU */
+	smp_mb();
+
+	if (exception_level == 1) {
+		if (raw_spin_trylock(&dbg_master_lock))
+			atomic_xchg(&kgdb_active, cpu);
+		goto cpu_master_loop;
+	}
+
+	/*
+	 * CPU will loop if it is a slave or request to become a kgdb
+	 * master cpu and acquire the kgdb_active lock:
+	 */
+	while (1) {
+cpu_loop:
+		if (kgdb_info[cpu].exception_state & DCPU_NEXT_MASTER) {
+			kgdb_info[cpu].exception_state &= ~DCPU_NEXT_MASTER;
+			goto cpu_master_loop;
+		} else if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) {
+			if (raw_spin_trylock(&dbg_master_lock)) {
+				atomic_xchg(&kgdb_active, cpu);
+				break;
+			}
+		} else if (kgdb_info[cpu].exception_state & DCPU_WANT_BT) {
+			dump_stack();
+			kgdb_info[cpu].exception_state &= ~DCPU_WANT_BT;
+		} else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) {
+			if (!raw_spin_is_locked(&dbg_slave_lock))
+				goto return_normal;
+		} else {
+return_normal:
+			/* Return to normal operation by executing any
+			 * hw breakpoint fixup.
+			 */
+			if (arch_kgdb_ops.correct_hw_break)
+				arch_kgdb_ops.correct_hw_break();
+			if (trace_on)
+				tracing_on();
+			kgdb_info[cpu].debuggerinfo = NULL;
+			kgdb_info[cpu].task = NULL;
+			kgdb_info[cpu].exception_state &=
+				~(DCPU_WANT_MASTER | DCPU_IS_SLAVE);
+			kgdb_info[cpu].enter_kgdb--;
+			smp_mb__before_atomic();
+			atomic_dec(&slaves_in_kgdb);
+			dbg_touch_watchdogs();
+			local_irq_restore(flags);
+			rcu_read_unlock();
+			return 0;
+		}
+		cpu_relax();
+	}
+
+	/*
+	 * For single stepping, try to only enter on the processor
+	 * that was single stepping.  To guard against a deadlock, the
+	 * kernel will only try for the value of sstep_tries before
+	 * giving up and continuing on.
+	 */
+	if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
+	    (kgdb_info[cpu].task &&
+	     kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) {
+		atomic_set(&kgdb_active, -1);
+		raw_spin_unlock(&dbg_master_lock);
+		dbg_touch_watchdogs();
+		local_irq_restore(flags);
+		rcu_read_unlock();
+
+		goto acquirelock;
+	}
+
+	if (!kgdb_io_ready(1)) {
+		kgdb_info[cpu].ret_state = 1;
+		goto kgdb_restore; /* No I/O connection, resume the system */
+	}
+
+	/*
+	 * Don't enter if we have hit a removed breakpoint.
+	 */
+	if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
+		goto kgdb_restore;
+
+	atomic_inc(&ignore_console_lock_warning);
+
+	/* Call the I/O driver's pre_exception routine */
+	if (dbg_io_ops->pre_exception)
+		dbg_io_ops->pre_exception();
+
+	/*
+	 * Get the passive CPU lock which will hold all the non-primary
+	 * CPU in a spin state while the debugger is active
+	 */
+	if (!kgdb_single_step)
+		raw_spin_lock(&dbg_slave_lock);
+
+#ifdef CONFIG_SMP
+	/* If send_ready set, slaves are already waiting */
+	if (ks->send_ready)
+		atomic_set(ks->send_ready, 1);
+
+	/* Signal the other CPUs to enter kgdb_wait() */
+	else if ((!kgdb_single_step) && kgdb_do_roundup)
+		kgdb_roundup_cpus();
+#endif
+
+	/*
+	 * Wait for the other CPUs to be notified and be waiting for us:
+	 */
+	time_left = MSEC_PER_SEC;
+	while (kgdb_do_roundup && --time_left &&
+	       (atomic_read(&masters_in_kgdb) + atomic_read(&slaves_in_kgdb)) !=
+		   online_cpus)
+		udelay(1000);
+	if (!time_left)
+		pr_crit("Timed out waiting for secondary CPUs.\n");
+
+	/*
+	 * At this point the primary processor is completely
+	 * in the debugger and all secondary CPUs are quiescent
+	 */
+	dbg_deactivate_sw_breakpoints();
+	kgdb_single_step = 0;
+	kgdb_contthread = current;
+	exception_level = 0;
+	trace_on = tracing_is_on();
+	if (trace_on)
+		tracing_off();
+
+	while (1) {
+cpu_master_loop:
+		if (dbg_kdb_mode) {
+			kgdb_connected = 1;
+			error = kdb_stub(ks);
+			if (error == -1)
+				continue;
+			kgdb_connected = 0;
+		} else {
+			/*
+			 * This is a brutal way to interfere with the debugger
+			 * and prevent gdb being used to poke at kernel memory.
+			 * This could cause trouble if lockdown is applied when
+			 * there is already an active gdb session. For now the
+			 * answer is simply "don't do that". Typically lockdown
+			 * *will* be applied before the debug core gets started
+			 * so only developers using kgdb for fairly advanced
+			 * early kernel debug can be biten by this. Hopefully
+			 * they are sophisticated enough to take care of
+			 * themselves, especially with help from the lockdown
+			 * message printed on the console!
+			 */
+			if (security_locked_down(LOCKDOWN_DBG_WRITE_KERNEL)) {
+				if (IS_ENABLED(CONFIG_KGDB_KDB)) {
+					/* Switch back to kdb if possible... */
+					dbg_kdb_mode = 1;
+					continue;
+				} else {
+					/* ... otherwise just bail */
+					break;
+				}
+			}
+			error = gdb_serial_stub(ks);
+		}
+
+		if (error == DBG_PASS_EVENT) {
+			dbg_kdb_mode = !dbg_kdb_mode;
+		} else if (error == DBG_SWITCH_CPU_EVENT) {
+			kgdb_info[dbg_switch_cpu].exception_state |=
+				DCPU_NEXT_MASTER;
+			goto cpu_loop;
+		} else {
+			kgdb_info[cpu].ret_state = error;
+			break;
+		}
+	}
+
+	dbg_activate_sw_breakpoints();
+
+	/* Call the I/O driver's post_exception routine */
+	if (dbg_io_ops->post_exception)
+		dbg_io_ops->post_exception();
+
+	atomic_dec(&ignore_console_lock_warning);
+
+	if (!kgdb_single_step) {
+		raw_spin_unlock(&dbg_slave_lock);
+		/* Wait till all the CPUs have quit from the debugger. */
+		while (kgdb_do_roundup && atomic_read(&slaves_in_kgdb))
+			cpu_relax();
+	}
+
+kgdb_restore:
+	if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
+		int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step);
+		if (kgdb_info[sstep_cpu].task)
+			kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid;
+		else
+			kgdb_sstep_pid = 0;
+	}
+	if (arch_kgdb_ops.correct_hw_break)
+		arch_kgdb_ops.correct_hw_break();
+	if (trace_on)
+		tracing_on();
+
+	kgdb_info[cpu].debuggerinfo = NULL;
+	kgdb_info[cpu].task = NULL;
+	kgdb_info[cpu].exception_state &=
+		~(DCPU_WANT_MASTER | DCPU_IS_SLAVE);
+	kgdb_info[cpu].enter_kgdb--;
+	smp_mb__before_atomic();
+	atomic_dec(&masters_in_kgdb);
+	/* Free kgdb_active */
+	atomic_set(&kgdb_active, -1);
+	raw_spin_unlock(&dbg_master_lock);
+	dbg_touch_watchdogs();
+	local_irq_restore(flags);
+	rcu_read_unlock();
+
+	return kgdb_info[cpu].ret_state;
+}
+NOKPROBE_SYMBOL(kgdb_cpu_enter);
+
+/*
+ * kgdb_handle_exception() - main entry point from a kernel exception
+ *
+ * Locking hierarchy:
+ *	interface locks, if any (begin_session)
+ *	kgdb lock (kgdb_active)
+ */
+int
+kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
+{
+	struct kgdb_state kgdb_var;
+	struct kgdb_state *ks = &kgdb_var;
+	int ret = 0;
+
+	if (arch_kgdb_ops.enable_nmi)
+		arch_kgdb_ops.enable_nmi(0);
+	/*
+	 * Avoid entering the debugger if we were triggered due to an oops
+	 * but panic_timeout indicates the system should automatically
+	 * reboot on panic. We don't want to get stuck waiting for input
+	 * on such systems, especially if its "just" an oops.
+	 */
+	if (signo != SIGTRAP && panic_timeout)
+		return 1;
+
+	memset(ks, 0, sizeof(struct kgdb_state));
+	ks->cpu			= raw_smp_processor_id();
+	ks->ex_vector		= evector;
+	ks->signo		= signo;
+	ks->err_code		= ecode;
+	ks->linux_regs		= regs;
+
+	if (kgdb_reenter_check(ks))
+		goto out; /* Ouch, double exception ! */
+	if (kgdb_info[ks->cpu].enter_kgdb != 0)
+		goto out;
+
+	ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
+out:
+	if (arch_kgdb_ops.enable_nmi)
+		arch_kgdb_ops.enable_nmi(1);
+	return ret;
+}
+NOKPROBE_SYMBOL(kgdb_handle_exception);
+
+/*
+ * GDB places a breakpoint at this function to know dynamically loaded objects.
+ */
+static int module_event(struct notifier_block *self, unsigned long val,
+	void *data)
+{
+	return 0;
+}
+
+static struct notifier_block dbg_module_load_nb = {
+	.notifier_call	= module_event,
+};
+
+int kgdb_nmicallback(int cpu, void *regs)
+{
+#ifdef CONFIG_SMP
+	struct kgdb_state kgdb_var;
+	struct kgdb_state *ks = &kgdb_var;
+
+	kgdb_info[cpu].rounding_up = false;
+
+	memset(ks, 0, sizeof(struct kgdb_state));
+	ks->cpu			= cpu;
+	ks->linux_regs		= regs;
+
+	if (kgdb_info[ks->cpu].enter_kgdb == 0 &&
+			raw_spin_is_locked(&dbg_master_lock)) {
+		kgdb_cpu_enter(ks, regs, DCPU_IS_SLAVE);
+		return 0;
+	}
+#endif
+	return 1;
+}
+NOKPROBE_SYMBOL(kgdb_nmicallback);
+
+int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code,
+							atomic_t *send_ready)
+{
+#ifdef CONFIG_SMP
+	if (!kgdb_io_ready(0) || !send_ready)
+		return 1;
+
+	if (kgdb_info[cpu].enter_kgdb == 0) {
+		struct kgdb_state kgdb_var;
+		struct kgdb_state *ks = &kgdb_var;
+
+		memset(ks, 0, sizeof(struct kgdb_state));
+		ks->cpu			= cpu;
+		ks->ex_vector		= trapnr;
+		ks->signo		= SIGTRAP;
+		ks->err_code		= err_code;
+		ks->linux_regs		= regs;
+		ks->send_ready		= send_ready;
+		kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
+		return 0;
+	}
+#endif
+	return 1;
+}
+NOKPROBE_SYMBOL(kgdb_nmicallin);
+
+static void kgdb_console_write(struct console *co, const char *s,
+   unsigned count)
+{
+	unsigned long flags;
+
+	/* If we're debugging, or KGDB has not connected, don't try
+	 * and print. */
+	if (!kgdb_connected || atomic_read(&kgdb_active) != -1 || dbg_kdb_mode)
+		return;
+
+	local_irq_save(flags);
+	gdbstub_msg_write(s, count);
+	local_irq_restore(flags);
+}
+
+static struct console kgdbcons = {
+	.name		= "kgdb",
+	.write		= kgdb_console_write,
+	.flags		= CON_PRINTBUFFER | CON_ENABLED,
+	.index		= -1,
+};
+
+static int __init opt_kgdb_con(char *str)
+{
+	kgdb_use_con = 1;
+
+	if (kgdb_io_module_registered && !kgdb_con_registered) {
+		register_console(&kgdbcons);
+		kgdb_con_registered = 1;
+	}
+
+	return 0;
+}
+
+early_param("kgdbcon", opt_kgdb_con);
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static void sysrq_handle_dbg(int key)
+{
+	if (!dbg_io_ops) {
+		pr_crit("ERROR: No KGDB I/O module available\n");
+		return;
+	}
+	if (!kgdb_connected) {
+#ifdef CONFIG_KGDB_KDB
+		if (!dbg_kdb_mode)
+			pr_crit("KGDB or $3#33 for KDB\n");
+#else
+		pr_crit("Entering KGDB\n");
+#endif
+	}
+
+	kgdb_breakpoint();
+}
+
+static const struct sysrq_key_op sysrq_dbg_op = {
+	.handler	= sysrq_handle_dbg,
+	.help_msg	= "debug(g)",
+	.action_msg	= "DEBUG",
+};
+#endif
+
+void kgdb_panic(const char *msg)
+{
+	if (!kgdb_io_module_registered)
+		return;
+
+	/*
+	 * We don't want to get stuck waiting for input from user if
+	 * "panic_timeout" indicates the system should automatically
+	 * reboot on panic.
+	 */
+	if (panic_timeout)
+		return;
+
+	debug_locks_off();
+	console_flush_on_panic(CONSOLE_FLUSH_PENDING);
+
+	if (dbg_kdb_mode)
+		kdb_printf("PANIC: %s\n", msg);
+
+	kgdb_breakpoint();
+}
+
+static void kgdb_initial_breakpoint(void)
+{
+	kgdb_break_asap = 0;
+
+	pr_crit("Waiting for connection from remote gdb...\n");
+	kgdb_breakpoint();
+}
+
+void __weak kgdb_arch_late(void)
+{
+}
+
+void __init dbg_late_init(void)
+{
+	dbg_is_early = false;
+	if (kgdb_io_module_registered)
+		kgdb_arch_late();
+	kdb_init(KDB_INIT_FULL);
+
+	if (kgdb_io_module_registered && kgdb_break_asap)
+		kgdb_initial_breakpoint();
+}
+
+static int
+dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x)
+{
+	/*
+	 * Take the following action on reboot notify depending on value:
+	 *    1 == Enter debugger
+	 *    0 == [the default] detach debug client
+	 *   -1 == Do nothing... and use this until the board resets
+	 */
+	switch (kgdbreboot) {
+	case 1:
+		kgdb_breakpoint();
+		goto done;
+	case -1:
+		goto done;
+	}
+	if (!dbg_kdb_mode)
+		gdbstub_exit(code);
+done:
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block dbg_reboot_notifier = {
+	.notifier_call		= dbg_notify_reboot,
+	.next			= NULL,
+	.priority		= INT_MAX,
+};
+
+static void kgdb_register_callbacks(void)
+{
+	if (!kgdb_io_module_registered) {
+		kgdb_io_module_registered = 1;
+		kgdb_arch_init();
+		if (!dbg_is_early)
+			kgdb_arch_late();
+		register_module_notifier(&dbg_module_load_nb);
+		register_reboot_notifier(&dbg_reboot_notifier);
+#ifdef CONFIG_MAGIC_SYSRQ
+		register_sysrq_key('g', &sysrq_dbg_op);
+#endif
+		if (kgdb_use_con && !kgdb_con_registered) {
+			register_console(&kgdbcons);
+			kgdb_con_registered = 1;
+		}
+	}
+}
+
+static void kgdb_unregister_callbacks(void)
+{
+	/*
+	 * When this routine is called KGDB should unregister from
+	 * handlers and clean up, making sure it is not handling any
+	 * break exceptions at the time.
+	 */
+	if (kgdb_io_module_registered) {
+		kgdb_io_module_registered = 0;
+		unregister_reboot_notifier(&dbg_reboot_notifier);
+		unregister_module_notifier(&dbg_module_load_nb);
+		kgdb_arch_exit();
+#ifdef CONFIG_MAGIC_SYSRQ
+		unregister_sysrq_key('g', &sysrq_dbg_op);
+#endif
+		if (kgdb_con_registered) {
+			unregister_console(&kgdbcons);
+			kgdb_con_registered = 0;
+		}
+	}
+}
+
+/**
+ *	kgdb_register_io_module - register KGDB IO module
+ *	@new_dbg_io_ops: the io ops vector
+ *
+ *	Register it with the KGDB core.
+ */
+int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops)
+{
+	struct kgdb_io *old_dbg_io_ops;
+	int err;
+
+	spin_lock(&kgdb_registration_lock);
+
+	old_dbg_io_ops = dbg_io_ops;
+	if (old_dbg_io_ops) {
+		if (!old_dbg_io_ops->deinit) {
+			spin_unlock(&kgdb_registration_lock);
+
+			pr_err("KGDB I/O driver %s can't replace %s.\n",
+				new_dbg_io_ops->name, old_dbg_io_ops->name);
+			return -EBUSY;
+		}
+		pr_info("Replacing I/O driver %s with %s\n",
+			old_dbg_io_ops->name, new_dbg_io_ops->name);
+	}
+
+	if (new_dbg_io_ops->init) {
+		err = new_dbg_io_ops->init();
+		if (err) {
+			spin_unlock(&kgdb_registration_lock);
+			return err;
+		}
+	}
+
+	dbg_io_ops = new_dbg_io_ops;
+
+	spin_unlock(&kgdb_registration_lock);
+
+	if (old_dbg_io_ops) {
+		old_dbg_io_ops->deinit();
+		return 0;
+	}
+
+	pr_info("Registered I/O driver %s\n", new_dbg_io_ops->name);
+
+	/* Arm KGDB now. */
+	kgdb_register_callbacks();
+
+	if (kgdb_break_asap &&
+	    (!dbg_is_early || IS_ENABLED(CONFIG_ARCH_HAS_EARLY_DEBUG)))
+		kgdb_initial_breakpoint();
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kgdb_register_io_module);
+
+/**
+ *	kgdb_unregister_io_module - unregister KGDB IO module
+ *	@old_dbg_io_ops: the io ops vector
+ *
+ *	Unregister it with the KGDB core.
+ */
+void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops)
+{
+	BUG_ON(kgdb_connected);
+
+	/*
+	 * KGDB is no longer able to communicate out, so
+	 * unregister our callbacks and reset state.
+	 */
+	kgdb_unregister_callbacks();
+
+	spin_lock(&kgdb_registration_lock);
+
+	WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops);
+	dbg_io_ops = NULL;
+
+	spin_unlock(&kgdb_registration_lock);
+
+	if (old_dbg_io_ops->deinit)
+		old_dbg_io_ops->deinit();
+
+	pr_info("Unregistered I/O driver %s, debugger disabled\n",
+		old_dbg_io_ops->name);
+}
+EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
+
+int dbg_io_get_char(void)
+{
+	int ret = dbg_io_ops->read_char();
+	if (ret == NO_POLL_CHAR)
+		return -1;
+	if (!dbg_kdb_mode)
+		return ret;
+	if (ret == 127)
+		return 8;
+	return ret;
+}
+
+/**
+ * kgdb_breakpoint - generate breakpoint exception
+ *
+ * This function will generate a breakpoint exception.  It is used at the
+ * beginning of a program to sync up with a debugger and can be used
+ * otherwise as a quick means to stop program execution and "break" into
+ * the debugger.
+ */
+noinline void kgdb_breakpoint(void)
+{
+	atomic_inc(&kgdb_setting_breakpoint);
+	wmb(); /* Sync point before breakpoint */
+	arch_kgdb_breakpoint();
+	wmb(); /* Sync point after breakpoint */
+	atomic_dec(&kgdb_setting_breakpoint);
+}
+EXPORT_SYMBOL_GPL(kgdb_breakpoint);
+
+static int __init opt_kgdb_wait(char *str)
+{
+	kgdb_break_asap = 1;
+
+	kdb_init(KDB_INIT_EARLY);
+	if (kgdb_io_module_registered &&
+	    IS_ENABLED(CONFIG_ARCH_HAS_EARLY_DEBUG))
+		kgdb_initial_breakpoint();
+
+	return 0;
+}
+
+early_param("kgdbwait", opt_kgdb_wait);
diff --git a/kernel/debug/debug_core.h b/kernel/debug/debug_core.h
new file mode 100644
index 000000000..cd22b5f68
--- /dev/null
+++ b/kernel/debug/debug_core.h
@@ -0,0 +1,87 @@
+/*
+ * Created by: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef _DEBUG_CORE_H_
+#define _DEBUG_CORE_H_
+/*
+ * These are the private implementation headers between the kernel
+ * debugger core and the debugger front end code.
+ */
+
+/* kernel debug core data structures */
+struct kgdb_state {
+	int			ex_vector;
+	int			signo;
+	int			err_code;
+	int			cpu;
+	int			pass_exception;
+	unsigned long		thr_query;
+	unsigned long		threadid;
+	long			kgdb_usethreadid;
+	struct pt_regs		*linux_regs;
+	atomic_t		*send_ready;
+};
+
+/* Exception state values */
+#define DCPU_WANT_MASTER 0x1 /* Waiting to become a master kgdb cpu */
+#define DCPU_NEXT_MASTER 0x2 /* Transition from one master cpu to another */
+#define DCPU_IS_SLAVE    0x4 /* Slave cpu enter exception */
+#define DCPU_WANT_BT     0x8 /* Slave cpu should backtrace then clear flag */
+
+struct debuggerinfo_struct {
+	void			*debuggerinfo;
+	struct task_struct	*task;
+	int			exception_state;
+	int			ret_state;
+	int			irq_depth;
+	int			enter_kgdb;
+	bool			rounding_up;
+};
+
+extern struct debuggerinfo_struct kgdb_info[];
+
+/* kernel debug core break point routines */
+extern int dbg_remove_all_break(void);
+extern int dbg_set_sw_break(unsigned long addr);
+extern int dbg_remove_sw_break(unsigned long addr);
+extern int dbg_activate_sw_breakpoints(void);
+extern int dbg_deactivate_sw_breakpoints(void);
+
+/* polled character access to i/o module */
+extern int dbg_io_get_char(void);
+
+/* stub return value for switching between the gdbstub and kdb */
+#define DBG_PASS_EVENT -12345
+/* Switch from one cpu to another */
+#define DBG_SWITCH_CPU_EVENT -123456
+extern int dbg_switch_cpu;
+
+/* gdbstub interface functions */
+extern int gdb_serial_stub(struct kgdb_state *ks);
+extern void gdbstub_msg_write(const char *s, int len);
+
+/* gdbstub functions used for kdb <-> gdbstub transition */
+extern int gdbstub_state(struct kgdb_state *ks, char *cmd);
+extern int dbg_kdb_mode;
+
+#ifdef CONFIG_KGDB_KDB
+extern int kdb_stub(struct kgdb_state *ks);
+extern int kdb_parse(const char *cmdstr);
+extern int kdb_common_init_state(struct kgdb_state *ks);
+extern int kdb_common_deinit_state(void);
+extern void kdb_dump_stack_on_cpu(int cpu);
+#else /* ! CONFIG_KGDB_KDB */
+static inline int kdb_stub(struct kgdb_state *ks)
+{
+	return DBG_PASS_EVENT;
+}
+#endif /* CONFIG_KGDB_KDB */
+
+#endif /* _DEBUG_CORE_H_ */
diff --git a/kernel/debug/gdbstub.c b/kernel/debug/gdbstub.c
new file mode 100644
index 000000000..9d34d2364
--- /dev/null
+++ b/kernel/debug/gdbstub.c
@@ -0,0 +1,1156 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Kernel Debug Core
+ *
+ * Maintainer: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002-2004 Timesys Corporation
+ * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com>
+ * Copyright (C) 2004 Pavel Machek <pavel@ucw.cz>
+ * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org>
+ * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
+ * Copyright (C) 2005-2009 Wind River Systems, Inc.
+ * Copyright (C) 2007 MontaVista Software, Inc.
+ * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * Contributors at various stages not listed above:
+ *  Jason Wessel ( jason.wessel@windriver.com )
+ *  George Anzinger <george@mvista.com>
+ *  Anurekh Saxena (anurekh.saxena@timesys.com)
+ *  Lake Stevens Instrument Division (Glenn Engel)
+ *  Jim Kingdon, Cygnus Support.
+ *
+ * Original KGDB stub: David Grothe <dave@gcom.com>,
+ * Tigran Aivazian <tigran@sco.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched/signal.h>
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+#include <linux/serial_core.h>
+#include <linux/reboot.h>
+#include <linux/uaccess.h>
+#include <asm/cacheflush.h>
+#include <asm/unaligned.h>
+#include "debug_core.h"
+
+#define KGDB_MAX_THREAD_QUERY 17
+
+/* Our I/O buffers. */
+static char			remcom_in_buffer[BUFMAX];
+static char			remcom_out_buffer[BUFMAX];
+static int			gdbstub_use_prev_in_buf;
+static int			gdbstub_prev_in_buf_pos;
+
+/* Storage for the registers, in GDB format. */
+static unsigned long		gdb_regs[(NUMREGBYTES +
+					sizeof(unsigned long) - 1) /
+					sizeof(unsigned long)];
+
+/*
+ * GDB remote protocol parser:
+ */
+
+#ifdef CONFIG_KGDB_KDB
+static int gdbstub_read_wait(void)
+{
+	int ret = -1;
+	int i;
+
+	if (unlikely(gdbstub_use_prev_in_buf)) {
+		if (gdbstub_prev_in_buf_pos < gdbstub_use_prev_in_buf)
+			return remcom_in_buffer[gdbstub_prev_in_buf_pos++];
+		else
+			gdbstub_use_prev_in_buf = 0;
+	}
+
+	/* poll any additional I/O interfaces that are defined */
+	while (ret < 0)
+		for (i = 0; kdb_poll_funcs[i] != NULL; i++) {
+			ret = kdb_poll_funcs[i]();
+			if (ret > 0)
+				break;
+		}
+	return ret;
+}
+#else
+static int gdbstub_read_wait(void)
+{
+	int ret = dbg_io_ops->read_char();
+	while (ret == NO_POLL_CHAR)
+		ret = dbg_io_ops->read_char();
+	return ret;
+}
+#endif
+/* scan for the sequence $<data>#<checksum> */
+static void get_packet(char *buffer)
+{
+	unsigned char checksum;
+	unsigned char xmitcsum;
+	int count;
+	char ch;
+
+	do {
+		/*
+		 * Spin and wait around for the start character, ignore all
+		 * other characters:
+		 */
+		while ((ch = (gdbstub_read_wait())) != '$')
+			/* nothing */;
+
+		kgdb_connected = 1;
+		checksum = 0;
+		xmitcsum = -1;
+
+		count = 0;
+
+		/*
+		 * now, read until a # or end of buffer is found:
+		 */
+		while (count < (BUFMAX - 1)) {
+			ch = gdbstub_read_wait();
+			if (ch == '#')
+				break;
+			checksum = checksum + ch;
+			buffer[count] = ch;
+			count = count + 1;
+		}
+
+		if (ch == '#') {
+			xmitcsum = hex_to_bin(gdbstub_read_wait()) << 4;
+			xmitcsum += hex_to_bin(gdbstub_read_wait());
+
+			if (checksum != xmitcsum)
+				/* failed checksum */
+				dbg_io_ops->write_char('-');
+			else
+				/* successful transfer */
+				dbg_io_ops->write_char('+');
+			if (dbg_io_ops->flush)
+				dbg_io_ops->flush();
+		}
+		buffer[count] = 0;
+	} while (checksum != xmitcsum);
+}
+
+/*
+ * Send the packet in buffer.
+ * Check for gdb connection if asked for.
+ */
+static void put_packet(char *buffer)
+{
+	unsigned char checksum;
+	int count;
+	char ch;
+
+	/*
+	 * $<packet info>#<checksum>.
+	 */
+	while (1) {
+		dbg_io_ops->write_char('$');
+		checksum = 0;
+		count = 0;
+
+		while ((ch = buffer[count])) {
+			dbg_io_ops->write_char(ch);
+			checksum += ch;
+			count++;
+		}
+
+		dbg_io_ops->write_char('#');
+		dbg_io_ops->write_char(hex_asc_hi(checksum));
+		dbg_io_ops->write_char(hex_asc_lo(checksum));
+		if (dbg_io_ops->flush)
+			dbg_io_ops->flush();
+
+		/* Now see what we get in reply. */
+		ch = gdbstub_read_wait();
+
+		if (ch == 3)
+			ch = gdbstub_read_wait();
+
+		/* If we get an ACK, we are done. */
+		if (ch == '+')
+			return;
+
+		/*
+		 * If we get the start of another packet, this means
+		 * that GDB is attempting to reconnect.  We will NAK
+		 * the packet being sent, and stop trying to send this
+		 * packet.
+		 */
+		if (ch == '$') {
+			dbg_io_ops->write_char('-');
+			if (dbg_io_ops->flush)
+				dbg_io_ops->flush();
+			return;
+		}
+	}
+}
+
+static char gdbmsgbuf[BUFMAX + 1];
+
+void gdbstub_msg_write(const char *s, int len)
+{
+	char *bufptr;
+	int wcount;
+	int i;
+
+	if (len == 0)
+		len = strlen(s);
+
+	/* 'O'utput */
+	gdbmsgbuf[0] = 'O';
+
+	/* Fill and send buffers... */
+	while (len > 0) {
+		bufptr = gdbmsgbuf + 1;
+
+		/* Calculate how many this time */
+		if ((len << 1) > (BUFMAX - 2))
+			wcount = (BUFMAX - 2) >> 1;
+		else
+			wcount = len;
+
+		/* Pack in hex chars */
+		for (i = 0; i < wcount; i++)
+			bufptr = hex_byte_pack(bufptr, s[i]);
+		*bufptr = '\0';
+
+		/* Move up */
+		s += wcount;
+		len -= wcount;
+
+		/* Write packet */
+		put_packet(gdbmsgbuf);
+	}
+}
+
+/*
+ * Convert the memory pointed to by mem into hex, placing result in
+ * buf.  Return a pointer to the last char put in buf (null). May
+ * return an error.
+ */
+char *kgdb_mem2hex(char *mem, char *buf, int count)
+{
+	char *tmp;
+	int err;
+
+	/*
+	 * We use the upper half of buf as an intermediate buffer for the
+	 * raw memory copy.  Hex conversion will work against this one.
+	 */
+	tmp = buf + count;
+
+	err = copy_from_kernel_nofault(tmp, mem, count);
+	if (err)
+		return NULL;
+	while (count > 0) {
+		buf = hex_byte_pack(buf, *tmp);
+		tmp++;
+		count--;
+	}
+	*buf = 0;
+
+	return buf;
+}
+
+/*
+ * Convert the hex array pointed to by buf into binary to be placed in
+ * mem.  Return a pointer to the character AFTER the last byte
+ * written.  May return an error.
+ */
+int kgdb_hex2mem(char *buf, char *mem, int count)
+{
+	char *tmp_raw;
+	char *tmp_hex;
+
+	/*
+	 * We use the upper half of buf as an intermediate buffer for the
+	 * raw memory that is converted from hex.
+	 */
+	tmp_raw = buf + count * 2;
+
+	tmp_hex = tmp_raw - 1;
+	while (tmp_hex >= buf) {
+		tmp_raw--;
+		*tmp_raw = hex_to_bin(*tmp_hex--);
+		*tmp_raw |= hex_to_bin(*tmp_hex--) << 4;
+	}
+
+	return copy_to_kernel_nofault(mem, tmp_raw, count);
+}
+
+/*
+ * While we find nice hex chars, build a long_val.
+ * Return number of chars processed.
+ */
+int kgdb_hex2long(char **ptr, unsigned long *long_val)
+{
+	int hex_val;
+	int num = 0;
+	int negate = 0;
+
+	*long_val = 0;
+
+	if (**ptr == '-') {
+		negate = 1;
+		(*ptr)++;
+	}
+	while (**ptr) {
+		hex_val = hex_to_bin(**ptr);
+		if (hex_val < 0)
+			break;
+
+		*long_val = (*long_val << 4) | hex_val;
+		num++;
+		(*ptr)++;
+	}
+
+	if (negate)
+		*long_val = -*long_val;
+
+	return num;
+}
+
+/*
+ * Copy the binary array pointed to by buf into mem.  Fix $, #, and
+ * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success.
+ * The input buf is overwritten with the result to write to mem.
+ */
+static int kgdb_ebin2mem(char *buf, char *mem, int count)
+{
+	int size = 0;
+	char *c = buf;
+
+	while (count-- > 0) {
+		c[size] = *buf++;
+		if (c[size] == 0x7d)
+			c[size] = *buf++ ^ 0x20;
+		size++;
+	}
+
+	return copy_to_kernel_nofault(mem, c, size);
+}
+
+#if DBG_MAX_REG_NUM > 0
+void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	int i;
+	int idx = 0;
+	char *ptr = (char *)gdb_regs;
+
+	for (i = 0; i < DBG_MAX_REG_NUM; i++) {
+		dbg_get_reg(i, ptr + idx, regs);
+		idx += dbg_reg_def[i].size;
+	}
+}
+
+void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	int i;
+	int idx = 0;
+	char *ptr = (char *)gdb_regs;
+
+	for (i = 0; i < DBG_MAX_REG_NUM; i++) {
+		dbg_set_reg(i, ptr + idx, regs);
+		idx += dbg_reg_def[i].size;
+	}
+}
+#endif /* DBG_MAX_REG_NUM > 0 */
+
+/* Write memory due to an 'M' or 'X' packet. */
+static int write_mem_msg(int binary)
+{
+	char *ptr = &remcom_in_buffer[1];
+	unsigned long addr;
+	unsigned long length;
+	int err;
+
+	if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
+	    kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
+		if (binary)
+			err = kgdb_ebin2mem(ptr, (char *)addr, length);
+		else
+			err = kgdb_hex2mem(ptr, (char *)addr, length);
+		if (err)
+			return err;
+		if (CACHE_FLUSH_IS_SAFE)
+			flush_icache_range(addr, addr + length);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static void error_packet(char *pkt, int error)
+{
+	error = -error;
+	pkt[0] = 'E';
+	pkt[1] = hex_asc[(error / 10)];
+	pkt[2] = hex_asc[(error % 10)];
+	pkt[3] = '\0';
+}
+
+/*
+ * Thread ID accessors. We represent a flat TID space to GDB, where
+ * the per CPU idle threads (which under Linux all have PID 0) are
+ * remapped to negative TIDs.
+ */
+
+#define BUF_THREAD_ID_SIZE	8
+
+static char *pack_threadid(char *pkt, unsigned char *id)
+{
+	unsigned char *limit;
+	int lzero = 1;
+
+	limit = id + (BUF_THREAD_ID_SIZE / 2);
+	while (id < limit) {
+		if (!lzero || *id != 0) {
+			pkt = hex_byte_pack(pkt, *id);
+			lzero = 0;
+		}
+		id++;
+	}
+
+	if (lzero)
+		pkt = hex_byte_pack(pkt, 0);
+
+	return pkt;
+}
+
+static void int_to_threadref(unsigned char *id, int value)
+{
+	put_unaligned_be32(value, id);
+}
+
+static struct task_struct *getthread(struct pt_regs *regs, int tid)
+{
+	/*
+	 * Non-positive TIDs are remapped to the cpu shadow information
+	 */
+	if (tid == 0 || tid == -1)
+		tid = -atomic_read(&kgdb_active) - 2;
+	if (tid < -1 && tid > -NR_CPUS - 2) {
+		if (kgdb_info[-tid - 2].task)
+			return kgdb_info[-tid - 2].task;
+		else
+			return idle_task(-tid - 2);
+	}
+	if (tid <= 0) {
+		printk(KERN_ERR "KGDB: Internal thread select error\n");
+		dump_stack();
+		return NULL;
+	}
+
+	/*
+	 * find_task_by_pid_ns() does not take the tasklist lock anymore
+	 * but is nicely RCU locked - hence is a pretty resilient
+	 * thing to use:
+	 */
+	return find_task_by_pid_ns(tid, &init_pid_ns);
+}
+
+
+/*
+ * Remap normal tasks to their real PID,
+ * CPU shadow threads are mapped to -CPU - 2
+ */
+static inline int shadow_pid(int realpid)
+{
+	if (realpid)
+		return realpid;
+
+	return -raw_smp_processor_id() - 2;
+}
+
+/*
+ * All the functions that start with gdb_cmd are the various
+ * operations to implement the handlers for the gdbserial protocol
+ * where KGDB is communicating with an external debugger
+ */
+
+/* Handle the '?' status packets */
+static void gdb_cmd_status(struct kgdb_state *ks)
+{
+	/*
+	 * We know that this packet is only sent
+	 * during initial connect.  So to be safe,
+	 * we clear out our breakpoints now in case
+	 * GDB is reconnecting.
+	 */
+	dbg_remove_all_break();
+
+	remcom_out_buffer[0] = 'S';
+	hex_byte_pack(&remcom_out_buffer[1], ks->signo);
+}
+
+static void gdb_get_regs_helper(struct kgdb_state *ks)
+{
+	struct task_struct *thread;
+	void *local_debuggerinfo;
+	int i;
+
+	thread = kgdb_usethread;
+	if (!thread) {
+		thread = kgdb_info[ks->cpu].task;
+		local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
+	} else {
+		local_debuggerinfo = NULL;
+		for_each_online_cpu(i) {
+			/*
+			 * Try to find the task on some other
+			 * or possibly this node if we do not
+			 * find the matching task then we try
+			 * to approximate the results.
+			 */
+			if (thread == kgdb_info[i].task)
+				local_debuggerinfo = kgdb_info[i].debuggerinfo;
+		}
+	}
+
+	/*
+	 * All threads that don't have debuggerinfo should be
+	 * in schedule() sleeping, since all other CPUs
+	 * are in kgdb_wait, and thus have debuggerinfo.
+	 */
+	if (local_debuggerinfo) {
+		pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
+	} else {
+		/*
+		 * Pull stuff saved during switch_to; nothing
+		 * else is accessible (or even particularly
+		 * relevant).
+		 *
+		 * This should be enough for a stack trace.
+		 */
+		sleeping_thread_to_gdb_regs(gdb_regs, thread);
+	}
+}
+
+/* Handle the 'g' get registers request */
+static void gdb_cmd_getregs(struct kgdb_state *ks)
+{
+	gdb_get_regs_helper(ks);
+	kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
+}
+
+/* Handle the 'G' set registers request */
+static void gdb_cmd_setregs(struct kgdb_state *ks)
+{
+	kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
+
+	if (kgdb_usethread && kgdb_usethread != current) {
+		error_packet(remcom_out_buffer, -EINVAL);
+	} else {
+		gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
+		strcpy(remcom_out_buffer, "OK");
+	}
+}
+
+/* Handle the 'm' memory read bytes */
+static void gdb_cmd_memread(struct kgdb_state *ks)
+{
+	char *ptr = &remcom_in_buffer[1];
+	unsigned long length;
+	unsigned long addr;
+	char *err;
+
+	if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
+					kgdb_hex2long(&ptr, &length) > 0) {
+		err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
+		if (!err)
+			error_packet(remcom_out_buffer, -EINVAL);
+	} else {
+		error_packet(remcom_out_buffer, -EINVAL);
+	}
+}
+
+/* Handle the 'M' memory write bytes */
+static void gdb_cmd_memwrite(struct kgdb_state *ks)
+{
+	int err = write_mem_msg(0);
+
+	if (err)
+		error_packet(remcom_out_buffer, err);
+	else
+		strcpy(remcom_out_buffer, "OK");
+}
+
+#if DBG_MAX_REG_NUM > 0
+static char *gdb_hex_reg_helper(int regnum, char *out)
+{
+	int i;
+	int offset = 0;
+
+	for (i = 0; i < regnum; i++)
+		offset += dbg_reg_def[i].size;
+	return kgdb_mem2hex((char *)gdb_regs + offset, out,
+			    dbg_reg_def[i].size);
+}
+
+/* Handle the 'p' individual register get */
+static void gdb_cmd_reg_get(struct kgdb_state *ks)
+{
+	unsigned long regnum;
+	char *ptr = &remcom_in_buffer[1];
+
+	kgdb_hex2long(&ptr, &regnum);
+	if (regnum >= DBG_MAX_REG_NUM) {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+	gdb_get_regs_helper(ks);
+	gdb_hex_reg_helper(regnum, remcom_out_buffer);
+}
+
+/* Handle the 'P' individual register set */
+static void gdb_cmd_reg_set(struct kgdb_state *ks)
+{
+	unsigned long regnum;
+	char *ptr = &remcom_in_buffer[1];
+	int i = 0;
+
+	kgdb_hex2long(&ptr, &regnum);
+	if (*ptr++ != '=' ||
+	    !(!kgdb_usethread || kgdb_usethread == current) ||
+	    !dbg_get_reg(regnum, gdb_regs, ks->linux_regs)) {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+	memset(gdb_regs, 0, sizeof(gdb_regs));
+	while (i < sizeof(gdb_regs) * 2)
+		if (hex_to_bin(ptr[i]) >= 0)
+			i++;
+		else
+			break;
+	i = i / 2;
+	kgdb_hex2mem(ptr, (char *)gdb_regs, i);
+	dbg_set_reg(regnum, gdb_regs, ks->linux_regs);
+	strcpy(remcom_out_buffer, "OK");
+}
+#endif /* DBG_MAX_REG_NUM > 0 */
+
+/* Handle the 'X' memory binary write bytes */
+static void gdb_cmd_binwrite(struct kgdb_state *ks)
+{
+	int err = write_mem_msg(1);
+
+	if (err)
+		error_packet(remcom_out_buffer, err);
+	else
+		strcpy(remcom_out_buffer, "OK");
+}
+
+/* Handle the 'D' or 'k', detach or kill packets */
+static void gdb_cmd_detachkill(struct kgdb_state *ks)
+{
+	int error;
+
+	/* The detach case */
+	if (remcom_in_buffer[0] == 'D') {
+		error = dbg_remove_all_break();
+		if (error < 0) {
+			error_packet(remcom_out_buffer, error);
+		} else {
+			strcpy(remcom_out_buffer, "OK");
+			kgdb_connected = 0;
+		}
+		put_packet(remcom_out_buffer);
+	} else {
+		/*
+		 * Assume the kill case, with no exit code checking,
+		 * trying to force detach the debugger:
+		 */
+		dbg_remove_all_break();
+		kgdb_connected = 0;
+	}
+}
+
+/* Handle the 'R' reboot packets */
+static int gdb_cmd_reboot(struct kgdb_state *ks)
+{
+	/* For now, only honor R0 */
+	if (strcmp(remcom_in_buffer, "R0") == 0) {
+		printk(KERN_CRIT "Executing emergency reboot\n");
+		strcpy(remcom_out_buffer, "OK");
+		put_packet(remcom_out_buffer);
+
+		/*
+		 * Execution should not return from
+		 * machine_emergency_restart()
+		 */
+		machine_emergency_restart();
+		kgdb_connected = 0;
+
+		return 1;
+	}
+	return 0;
+}
+
+/* Handle the 'q' query packets */
+static void gdb_cmd_query(struct kgdb_state *ks)
+{
+	struct task_struct *g;
+	struct task_struct *p;
+	unsigned char thref[BUF_THREAD_ID_SIZE];
+	char *ptr;
+	int i;
+	int cpu;
+	int finished = 0;
+
+	switch (remcom_in_buffer[1]) {
+	case 's':
+	case 'f':
+		if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10))
+			break;
+
+		i = 0;
+		remcom_out_buffer[0] = 'm';
+		ptr = remcom_out_buffer + 1;
+		if (remcom_in_buffer[1] == 'f') {
+			/* Each cpu is a shadow thread */
+			for_each_online_cpu(cpu) {
+				ks->thr_query = 0;
+				int_to_threadref(thref, -cpu - 2);
+				ptr = pack_threadid(ptr, thref);
+				*(ptr++) = ',';
+				i++;
+			}
+		}
+
+		for_each_process_thread(g, p) {
+			if (i >= ks->thr_query && !finished) {
+				int_to_threadref(thref, p->pid);
+				ptr = pack_threadid(ptr, thref);
+				*(ptr++) = ',';
+				ks->thr_query++;
+				if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
+					finished = 1;
+			}
+			i++;
+		}
+
+		*(--ptr) = '\0';
+		break;
+
+	case 'C':
+		/* Current thread id */
+		strcpy(remcom_out_buffer, "QC");
+		ks->threadid = shadow_pid(current->pid);
+		int_to_threadref(thref, ks->threadid);
+		pack_threadid(remcom_out_buffer + 2, thref);
+		break;
+	case 'T':
+		if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16))
+			break;
+
+		ks->threadid = 0;
+		ptr = remcom_in_buffer + 17;
+		kgdb_hex2long(&ptr, &ks->threadid);
+		if (!getthread(ks->linux_regs, ks->threadid)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		if ((int)ks->threadid > 0) {
+			kgdb_mem2hex(getthread(ks->linux_regs,
+					ks->threadid)->comm,
+					remcom_out_buffer, 16);
+		} else {
+			static char tmpstr[23 + BUF_THREAD_ID_SIZE];
+
+			sprintf(tmpstr, "shadowCPU%d",
+					(int)(-ks->threadid - 2));
+			kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
+		}
+		break;
+#ifdef CONFIG_KGDB_KDB
+	case 'R':
+		if (strncmp(remcom_in_buffer, "qRcmd,", 6) == 0) {
+			int len = strlen(remcom_in_buffer + 6);
+
+			if ((len % 2) != 0) {
+				strcpy(remcom_out_buffer, "E01");
+				break;
+			}
+			kgdb_hex2mem(remcom_in_buffer + 6,
+				     remcom_out_buffer, len);
+			len = len / 2;
+			remcom_out_buffer[len++] = 0;
+
+			kdb_common_init_state(ks);
+			kdb_parse(remcom_out_buffer);
+			kdb_common_deinit_state();
+
+			strcpy(remcom_out_buffer, "OK");
+		}
+		break;
+#endif
+#ifdef CONFIG_HAVE_ARCH_KGDB_QXFER_PKT
+	case 'S':
+		if (!strncmp(remcom_in_buffer, "qSupported:", 11))
+			strcpy(remcom_out_buffer, kgdb_arch_gdb_stub_feature);
+		break;
+	case 'X':
+		if (!strncmp(remcom_in_buffer, "qXfer:", 6))
+			kgdb_arch_handle_qxfer_pkt(remcom_in_buffer,
+						   remcom_out_buffer);
+		break;
+#endif
+	default:
+		break;
+	}
+}
+
+/* Handle the 'H' task query packets */
+static void gdb_cmd_task(struct kgdb_state *ks)
+{
+	struct task_struct *thread;
+	char *ptr;
+
+	switch (remcom_in_buffer[1]) {
+	case 'g':
+		ptr = &remcom_in_buffer[2];
+		kgdb_hex2long(&ptr, &ks->threadid);
+		thread = getthread(ks->linux_regs, ks->threadid);
+		if (!thread && ks->threadid > 0) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		kgdb_usethread = thread;
+		ks->kgdb_usethreadid = ks->threadid;
+		strcpy(remcom_out_buffer, "OK");
+		break;
+	case 'c':
+		ptr = &remcom_in_buffer[2];
+		kgdb_hex2long(&ptr, &ks->threadid);
+		if (!ks->threadid) {
+			kgdb_contthread = NULL;
+		} else {
+			thread = getthread(ks->linux_regs, ks->threadid);
+			if (!thread && ks->threadid > 0) {
+				error_packet(remcom_out_buffer, -EINVAL);
+				break;
+			}
+			kgdb_contthread = thread;
+		}
+		strcpy(remcom_out_buffer, "OK");
+		break;
+	}
+}
+
+/* Handle the 'T' thread query packets */
+static void gdb_cmd_thread(struct kgdb_state *ks)
+{
+	char *ptr = &remcom_in_buffer[1];
+	struct task_struct *thread;
+
+	kgdb_hex2long(&ptr, &ks->threadid);
+	thread = getthread(ks->linux_regs, ks->threadid);
+	if (thread)
+		strcpy(remcom_out_buffer, "OK");
+	else
+		error_packet(remcom_out_buffer, -EINVAL);
+}
+
+/* Handle the 'z' or 'Z' breakpoint remove or set packets */
+static void gdb_cmd_break(struct kgdb_state *ks)
+{
+	/*
+	 * Since GDB-5.3, it's been drafted that '0' is a software
+	 * breakpoint, '1' is a hardware breakpoint, so let's do that.
+	 */
+	char *bpt_type = &remcom_in_buffer[1];
+	char *ptr = &remcom_in_buffer[2];
+	unsigned long addr;
+	unsigned long length;
+	int error = 0;
+
+	if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
+		/* Unsupported */
+		if (*bpt_type > '4')
+			return;
+	} else {
+		if (*bpt_type != '0' && *bpt_type != '1')
+			/* Unsupported. */
+			return;
+	}
+
+	/*
+	 * Test if this is a hardware breakpoint, and
+	 * if we support it:
+	 */
+	if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
+		/* Unsupported. */
+		return;
+
+	if (*(ptr++) != ',') {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+	if (!kgdb_hex2long(&ptr, &addr)) {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+	if (*(ptr++) != ',' ||
+		!kgdb_hex2long(&ptr, &length)) {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+
+	if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
+		error = dbg_set_sw_break(addr);
+	else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
+		error = dbg_remove_sw_break(addr);
+	else if (remcom_in_buffer[0] == 'Z')
+		error = arch_kgdb_ops.set_hw_breakpoint(addr,
+			(int)length, *bpt_type - '0');
+	else if (remcom_in_buffer[0] == 'z')
+		error = arch_kgdb_ops.remove_hw_breakpoint(addr,
+			(int) length, *bpt_type - '0');
+
+	if (error == 0)
+		strcpy(remcom_out_buffer, "OK");
+	else
+		error_packet(remcom_out_buffer, error);
+}
+
+/* Handle the 'C' signal / exception passing packets */
+static int gdb_cmd_exception_pass(struct kgdb_state *ks)
+{
+	/* C09 == pass exception
+	 * C15 == detach kgdb, pass exception
+	 */
+	if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
+
+		ks->pass_exception = 1;
+		remcom_in_buffer[0] = 'c';
+
+	} else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
+
+		ks->pass_exception = 1;
+		remcom_in_buffer[0] = 'D';
+		dbg_remove_all_break();
+		kgdb_connected = 0;
+		return 1;
+
+	} else {
+		gdbstub_msg_write("KGDB only knows signal 9 (pass)"
+			" and 15 (pass and disconnect)\n"
+			"Executing a continue without signal passing\n", 0);
+		remcom_in_buffer[0] = 'c';
+	}
+
+	/* Indicate fall through */
+	return -1;
+}
+
+/*
+ * This function performs all gdbserial command processing
+ */
+int gdb_serial_stub(struct kgdb_state *ks)
+{
+	int error = 0;
+	int tmp;
+
+	/* Initialize comm buffer and globals. */
+	memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
+	kgdb_usethread = kgdb_info[ks->cpu].task;
+	ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
+	ks->pass_exception = 0;
+
+	if (kgdb_connected) {
+		unsigned char thref[BUF_THREAD_ID_SIZE];
+		char *ptr;
+
+		/* Reply to host that an exception has occurred */
+		ptr = remcom_out_buffer;
+		*ptr++ = 'T';
+		ptr = hex_byte_pack(ptr, ks->signo);
+		ptr += strlen(strcpy(ptr, "thread:"));
+		int_to_threadref(thref, shadow_pid(current->pid));
+		ptr = pack_threadid(ptr, thref);
+		*ptr++ = ';';
+		put_packet(remcom_out_buffer);
+	}
+
+	while (1) {
+		error = 0;
+
+		/* Clear the out buffer. */
+		memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
+
+		get_packet(remcom_in_buffer);
+
+		switch (remcom_in_buffer[0]) {
+		case '?': /* gdbserial status */
+			gdb_cmd_status(ks);
+			break;
+		case 'g': /* return the value of the CPU registers */
+			gdb_cmd_getregs(ks);
+			break;
+		case 'G': /* set the value of the CPU registers - return OK */
+			gdb_cmd_setregs(ks);
+			break;
+		case 'm': /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
+			gdb_cmd_memread(ks);
+			break;
+		case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
+			gdb_cmd_memwrite(ks);
+			break;
+#if DBG_MAX_REG_NUM > 0
+		case 'p': /* pXX Return gdb register XX (in hex) */
+			gdb_cmd_reg_get(ks);
+			break;
+		case 'P': /* PXX=aaaa Set gdb register XX to aaaa (in hex) */
+			gdb_cmd_reg_set(ks);
+			break;
+#endif /* DBG_MAX_REG_NUM > 0 */
+		case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
+			gdb_cmd_binwrite(ks);
+			break;
+			/* kill or detach. KGDB should treat this like a
+			 * continue.
+			 */
+		case 'D': /* Debugger detach */
+		case 'k': /* Debugger detach via kill */
+			gdb_cmd_detachkill(ks);
+			goto default_handle;
+		case 'R': /* Reboot */
+			if (gdb_cmd_reboot(ks))
+				goto default_handle;
+			break;
+		case 'q': /* query command */
+			gdb_cmd_query(ks);
+			break;
+		case 'H': /* task related */
+			gdb_cmd_task(ks);
+			break;
+		case 'T': /* Query thread status */
+			gdb_cmd_thread(ks);
+			break;
+		case 'z': /* Break point remove */
+		case 'Z': /* Break point set */
+			gdb_cmd_break(ks);
+			break;
+#ifdef CONFIG_KGDB_KDB
+		case '3': /* Escape into back into kdb */
+			if (remcom_in_buffer[1] == '\0') {
+				gdb_cmd_detachkill(ks);
+				return DBG_PASS_EVENT;
+			}
+			fallthrough;
+#endif
+		case 'C': /* Exception passing */
+			tmp = gdb_cmd_exception_pass(ks);
+			if (tmp > 0)
+				goto default_handle;
+			if (tmp == 0)
+				break;
+			fallthrough;	/* on tmp < 0 */
+		case 'c': /* Continue packet */
+		case 's': /* Single step packet */
+			if (kgdb_contthread && kgdb_contthread != current) {
+				/* Can't switch threads in kgdb */
+				error_packet(remcom_out_buffer, -EINVAL);
+				break;
+			}
+			fallthrough;	/* to default processing */
+		default:
+default_handle:
+			error = kgdb_arch_handle_exception(ks->ex_vector,
+						ks->signo,
+						ks->err_code,
+						remcom_in_buffer,
+						remcom_out_buffer,
+						ks->linux_regs);
+			/*
+			 * Leave cmd processing on error, detach,
+			 * kill, continue, or single step.
+			 */
+			if (error >= 0 || remcom_in_buffer[0] == 'D' ||
+			    remcom_in_buffer[0] == 'k') {
+				error = 0;
+				goto kgdb_exit;
+			}
+
+		}
+
+		/* reply to the request */
+		put_packet(remcom_out_buffer);
+	}
+
+kgdb_exit:
+	if (ks->pass_exception)
+		error = 1;
+	return error;
+}
+
+int gdbstub_state(struct kgdb_state *ks, char *cmd)
+{
+	int error;
+
+	switch (cmd[0]) {
+	case 'e':
+		error = kgdb_arch_handle_exception(ks->ex_vector,
+						   ks->signo,
+						   ks->err_code,
+						   remcom_in_buffer,
+						   remcom_out_buffer,
+						   ks->linux_regs);
+		return error;
+	case 's':
+	case 'c':
+		strscpy(remcom_in_buffer, cmd, sizeof(remcom_in_buffer));
+		return 0;
+	case '$':
+		strscpy(remcom_in_buffer, cmd, sizeof(remcom_in_buffer));
+		gdbstub_use_prev_in_buf = strlen(remcom_in_buffer);
+		gdbstub_prev_in_buf_pos = 0;
+		return 0;
+	}
+	dbg_io_ops->write_char('+');
+	put_packet(remcom_out_buffer);
+	return 0;
+}
+
+/**
+ * gdbstub_exit - Send an exit message to GDB
+ * @status: The exit code to report.
+ */
+void gdbstub_exit(int status)
+{
+	unsigned char checksum, ch, buffer[3];
+	int loop;
+
+	if (!kgdb_connected)
+		return;
+	kgdb_connected = 0;
+
+	if (!dbg_io_ops || dbg_kdb_mode)
+		return;
+
+	buffer[0] = 'W';
+	buffer[1] = hex_asc_hi(status);
+	buffer[2] = hex_asc_lo(status);
+
+	dbg_io_ops->write_char('$');
+	checksum = 0;
+
+	for (loop = 0; loop < 3; loop++) {
+		ch = buffer[loop];
+		checksum += ch;
+		dbg_io_ops->write_char(ch);
+	}
+
+	dbg_io_ops->write_char('#');
+	dbg_io_ops->write_char(hex_asc_hi(checksum));
+	dbg_io_ops->write_char(hex_asc_lo(checksum));
+
+	/* make sure the output is flushed, lest the bootloader clobber it */
+	if (dbg_io_ops->flush)
+		dbg_io_ops->flush();
+}
diff --git a/kernel/debug/kdb/.gitignore b/kernel/debug/kdb/.gitignore
new file mode 100644
index 000000000..df259542a
--- /dev/null
+++ b/kernel/debug/kdb/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+gen-kdb_cmds.c
diff --git a/kernel/debug/kdb/Makefile b/kernel/debug/kdb/Makefile
new file mode 100644
index 000000000..efac857c5
--- /dev/null
+++ b/kernel/debug/kdb/Makefile
@@ -0,0 +1,24 @@
+# This file is subject to the terms and conditions of the GNU General Public
+# License.  See the file "COPYING" in the main directory of this archive
+# for more details.
+#
+# Copyright (c) 1999-2004 Silicon Graphics, Inc.  All Rights Reserved.
+# Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
+#
+
+obj-y := kdb_io.o kdb_main.o kdb_support.o kdb_bt.o gen-kdb_cmds.o kdb_bp.o kdb_debugger.o
+obj-$(CONFIG_KDB_KEYBOARD)    += kdb_keyboard.o
+
+clean-files := gen-kdb_cmds.c
+
+quiet_cmd_gen-kdb = GENKDB  $@
+      cmd_gen-kdb = $(AWK) 'BEGIN {print "\#include <linux/stddef.h>"; print "\#include <linux/init.h>"} \
+		/^\#/{next} \
+		/^[ \t]*$$/{next} \
+		{gsub(/"/, "\\\"", $$0); \
+		  print "static __initdata char kdb_cmd" cmds++ "[] = \"" $$0 "\\n\";"} \
+		END {print "extern char *kdb_cmds[]; char __initdata *kdb_cmds[] = {"; for (i = 0; i < cmds; ++i) {print "  kdb_cmd" i ","}; print("  NULL\n};");}' \
+		$(filter-out %/Makefile,$^) > $@#
+
+$(obj)/gen-kdb_cmds.c:	$(src)/kdb_cmds $(src)/Makefile
+	$(call cmd,gen-kdb)
diff --git a/kernel/debug/kdb/kdb_bp.c b/kernel/debug/kdb/kdb_bp.c
new file mode 100644
index 000000000..372025cf1
--- /dev/null
+++ b/kernel/debug/kdb/kdb_bp.c
@@ -0,0 +1,591 @@
+/*
+ * Kernel Debugger Architecture Independent Breakpoint Handler
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 1999-2004 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ */
+
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/kdb.h>
+#include <linux/kgdb.h>
+#include <linux/smp.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include "kdb_private.h"
+
+/*
+ * Table of kdb_breakpoints
+ */
+kdb_bp_t kdb_breakpoints[KDB_MAXBPT];
+
+static void kdb_setsinglestep(struct pt_regs *regs)
+{
+	KDB_STATE_SET(DOING_SS);
+}
+
+static char *kdb_rwtypes[] = {
+	"Instruction(i)",
+	"Instruction(Register)",
+	"Data Write",
+	"I/O",
+	"Data Access"
+};
+
+static char *kdb_bptype(kdb_bp_t *bp)
+{
+	if (bp->bp_type < 0 || bp->bp_type > 4)
+		return "";
+
+	return kdb_rwtypes[bp->bp_type];
+}
+
+static int kdb_parsebp(int argc, const char **argv, int *nextargp, kdb_bp_t *bp)
+{
+	int nextarg = *nextargp;
+	int diag;
+
+	bp->bph_length = 1;
+	if ((argc + 1) != nextarg) {
+		if (strncasecmp(argv[nextarg], "datar", sizeof("datar")) == 0)
+			bp->bp_type = BP_ACCESS_WATCHPOINT;
+		else if (strncasecmp(argv[nextarg], "dataw", sizeof("dataw")) == 0)
+			bp->bp_type = BP_WRITE_WATCHPOINT;
+		else if (strncasecmp(argv[nextarg], "inst", sizeof("inst")) == 0)
+			bp->bp_type = BP_HARDWARE_BREAKPOINT;
+		else
+			return KDB_ARGCOUNT;
+
+		bp->bph_length = 1;
+
+		nextarg++;
+
+		if ((argc + 1) != nextarg) {
+			unsigned long len;
+
+			diag = kdbgetularg((char *)argv[nextarg],
+					   &len);
+			if (diag)
+				return diag;
+
+
+			if (len > 8)
+				return KDB_BADLENGTH;
+
+			bp->bph_length = len;
+			nextarg++;
+		}
+
+		if ((argc + 1) != nextarg)
+			return KDB_ARGCOUNT;
+	}
+
+	*nextargp = nextarg;
+	return 0;
+}
+
+static int _kdb_bp_remove(kdb_bp_t *bp)
+{
+	int ret = 1;
+	if (!bp->bp_installed)
+		return ret;
+	if (!bp->bp_type)
+		ret = dbg_remove_sw_break(bp->bp_addr);
+	else
+		ret = arch_kgdb_ops.remove_hw_breakpoint(bp->bp_addr,
+			 bp->bph_length,
+			 bp->bp_type);
+	if (ret == 0)
+		bp->bp_installed = 0;
+	return ret;
+}
+
+static void kdb_handle_bp(struct pt_regs *regs, kdb_bp_t *bp)
+{
+	if (KDB_DEBUG(BP))
+		kdb_printf("regs->ip = 0x%lx\n", instruction_pointer(regs));
+
+	/*
+	 * Setup single step
+	 */
+	kdb_setsinglestep(regs);
+
+	/*
+	 * Reset delay attribute
+	 */
+	bp->bp_delay = 0;
+	bp->bp_delayed = 1;
+}
+
+static int _kdb_bp_install(struct pt_regs *regs, kdb_bp_t *bp)
+{
+	int ret;
+	/*
+	 * Install the breakpoint, if it is not already installed.
+	 */
+
+	if (KDB_DEBUG(BP))
+		kdb_printf("%s: bp_installed %d\n",
+			   __func__, bp->bp_installed);
+	if (!KDB_STATE(SSBPT))
+		bp->bp_delay = 0;
+	if (bp->bp_installed)
+		return 1;
+	if (bp->bp_delay || (bp->bp_delayed && KDB_STATE(DOING_SS))) {
+		if (KDB_DEBUG(BP))
+			kdb_printf("%s: delayed bp\n", __func__);
+		kdb_handle_bp(regs, bp);
+		return 0;
+	}
+	if (!bp->bp_type)
+		ret = dbg_set_sw_break(bp->bp_addr);
+	else
+		ret = arch_kgdb_ops.set_hw_breakpoint(bp->bp_addr,
+			 bp->bph_length,
+			 bp->bp_type);
+	if (ret == 0) {
+		bp->bp_installed = 1;
+	} else {
+		kdb_printf("%s: failed to set breakpoint at 0x%lx\n",
+			   __func__, bp->bp_addr);
+		if (!bp->bp_type) {
+			kdb_printf("Software breakpoints are unavailable.\n"
+				   "  Boot the kernel with rodata=off\n"
+				   "  OR use hw breaks: help bph\n");
+		}
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * kdb_bp_install
+ *
+ *	Install kdb_breakpoints prior to returning from the
+ *	kernel debugger.  This allows the kdb_breakpoints to be set
+ *	upon functions that are used internally by kdb, such as
+ *	printk().  This function is only called once per kdb session.
+ */
+void kdb_bp_install(struct pt_regs *regs)
+{
+	int i;
+
+	for (i = 0; i < KDB_MAXBPT; i++) {
+		kdb_bp_t *bp = &kdb_breakpoints[i];
+
+		if (KDB_DEBUG(BP)) {
+			kdb_printf("%s: bp %d bp_enabled %d\n",
+				   __func__, i, bp->bp_enabled);
+		}
+		if (bp->bp_enabled)
+			_kdb_bp_install(regs, bp);
+	}
+}
+
+/*
+ * kdb_bp_remove
+ *
+ *	Remove kdb_breakpoints upon entry to the kernel debugger.
+ *
+ * Parameters:
+ *	None.
+ * Outputs:
+ *	None.
+ * Returns:
+ *	None.
+ * Locking:
+ *	None.
+ * Remarks:
+ */
+void kdb_bp_remove(void)
+{
+	int i;
+
+	for (i = KDB_MAXBPT - 1; i >= 0; i--) {
+		kdb_bp_t *bp = &kdb_breakpoints[i];
+
+		if (KDB_DEBUG(BP)) {
+			kdb_printf("%s: bp %d bp_enabled %d\n",
+				   __func__, i, bp->bp_enabled);
+		}
+		if (bp->bp_enabled)
+			_kdb_bp_remove(bp);
+	}
+}
+
+
+/*
+ * kdb_printbp
+ *
+ *	Internal function to format and print a breakpoint entry.
+ *
+ * Parameters:
+ *	None.
+ * Outputs:
+ *	None.
+ * Returns:
+ *	None.
+ * Locking:
+ *	None.
+ * Remarks:
+ */
+
+static void kdb_printbp(kdb_bp_t *bp, int i)
+{
+	kdb_printf("%s ", kdb_bptype(bp));
+	kdb_printf("BP #%d at ", i);
+	kdb_symbol_print(bp->bp_addr, NULL, KDB_SP_DEFAULT);
+
+	if (bp->bp_enabled)
+		kdb_printf("\n    is enabled ");
+	else
+		kdb_printf("\n    is disabled");
+
+	kdb_printf("  addr at %016lx, hardtype=%d installed=%d\n",
+		   bp->bp_addr, bp->bp_type, bp->bp_installed);
+
+	kdb_printf("\n");
+}
+
+/*
+ * kdb_bp
+ *
+ *	Handle the bp commands.
+ *
+ *	[bp|bph] <addr-expression> [DATAR|DATAW]
+ *
+ * Parameters:
+ *	argc	Count of arguments in argv
+ *	argv	Space delimited command line arguments
+ * Outputs:
+ *	None.
+ * Returns:
+ *	Zero for success, a kdb diagnostic if failure.
+ * Locking:
+ *	None.
+ * Remarks:
+ *
+ *	bp	Set breakpoint on all cpus.  Only use hardware assist if need.
+ *	bph	Set breakpoint on all cpus.  Force hardware register
+ */
+
+static int kdb_bp(int argc, const char **argv)
+{
+	int i, bpno;
+	kdb_bp_t *bp, *bp_check;
+	int diag;
+	char *symname = NULL;
+	long offset = 0ul;
+	int nextarg;
+	kdb_bp_t template = {0};
+
+	if (argc == 0) {
+		/*
+		 * Display breakpoint table
+		 */
+		for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT;
+		     bpno++, bp++) {
+			if (bp->bp_free)
+				continue;
+			kdb_printbp(bp, bpno);
+		}
+
+		return 0;
+	}
+
+	nextarg = 1;
+	diag = kdbgetaddrarg(argc, argv, &nextarg, &template.bp_addr,
+			     &offset, &symname);
+	if (diag)
+		return diag;
+	if (!template.bp_addr)
+		return KDB_BADINT;
+
+	/*
+	 * This check is redundant (since the breakpoint machinery should
+	 * be doing the same check during kdb_bp_install) but gives the
+	 * user immediate feedback.
+	 */
+	diag = kgdb_validate_break_address(template.bp_addr);
+	if (diag)
+		return diag;
+
+	/*
+	 * Find an empty bp structure to allocate
+	 */
+	for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT; bpno++, bp++) {
+		if (bp->bp_free)
+			break;
+	}
+
+	if (bpno == KDB_MAXBPT)
+		return KDB_TOOMANYBPT;
+
+	if (strcmp(argv[0], "bph") == 0) {
+		template.bp_type = BP_HARDWARE_BREAKPOINT;
+		diag = kdb_parsebp(argc, argv, &nextarg, &template);
+		if (diag)
+			return diag;
+	} else {
+		template.bp_type = BP_BREAKPOINT;
+	}
+
+	/*
+	 * Check for clashing breakpoints.
+	 *
+	 * Note, in this design we can't have hardware breakpoints
+	 * enabled for both read and write on the same address.
+	 */
+	for (i = 0, bp_check = kdb_breakpoints; i < KDB_MAXBPT;
+	     i++, bp_check++) {
+		if (!bp_check->bp_free &&
+		    bp_check->bp_addr == template.bp_addr) {
+			kdb_printf("You already have a breakpoint at "
+				   kdb_bfd_vma_fmt0 "\n", template.bp_addr);
+			return KDB_DUPBPT;
+		}
+	}
+
+	template.bp_enabled = 1;
+
+	/*
+	 * Actually allocate the breakpoint found earlier
+	 */
+	*bp = template;
+	bp->bp_free = 0;
+
+	kdb_printbp(bp, bpno);
+
+	return 0;
+}
+
+/*
+ * kdb_bc
+ *
+ *	Handles the 'bc', 'be', and 'bd' commands
+ *
+ *	[bd|bc|be] <breakpoint-number>
+ *	[bd|bc|be] *
+ *
+ * Parameters:
+ *	argc	Count of arguments in argv
+ *	argv	Space delimited command line arguments
+ * Outputs:
+ *	None.
+ * Returns:
+ *	Zero for success, a kdb diagnostic for failure
+ * Locking:
+ *	None.
+ * Remarks:
+ */
+static int kdb_bc(int argc, const char **argv)
+{
+	unsigned long addr;
+	kdb_bp_t *bp = NULL;
+	int lowbp = KDB_MAXBPT;
+	int highbp = 0;
+	int done = 0;
+	int i;
+	int diag = 0;
+
+	int cmd;			/* KDBCMD_B? */
+#define KDBCMD_BC	0
+#define KDBCMD_BE	1
+#define KDBCMD_BD	2
+
+	if (strcmp(argv[0], "be") == 0)
+		cmd = KDBCMD_BE;
+	else if (strcmp(argv[0], "bd") == 0)
+		cmd = KDBCMD_BD;
+	else
+		cmd = KDBCMD_BC;
+
+	if (argc != 1)
+		return KDB_ARGCOUNT;
+
+	if (strcmp(argv[1], "*") == 0) {
+		lowbp = 0;
+		highbp = KDB_MAXBPT;
+	} else {
+		diag = kdbgetularg(argv[1], &addr);
+		if (diag)
+			return diag;
+
+		/*
+		 * For addresses less than the maximum breakpoint number,
+		 * assume that the breakpoint number is desired.
+		 */
+		if (addr < KDB_MAXBPT) {
+			lowbp = highbp = addr;
+			highbp++;
+		} else {
+			for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT;
+			    i++, bp++) {
+				if (bp->bp_addr == addr) {
+					lowbp = highbp = i;
+					highbp++;
+					break;
+				}
+			}
+		}
+	}
+
+	/*
+	 * Now operate on the set of breakpoints matching the input
+	 * criteria (either '*' for all, or an individual breakpoint).
+	 */
+	for (bp = &kdb_breakpoints[lowbp], i = lowbp;
+	    i < highbp;
+	    i++, bp++) {
+		if (bp->bp_free)
+			continue;
+
+		done++;
+
+		switch (cmd) {
+		case KDBCMD_BC:
+			bp->bp_enabled = 0;
+
+			kdb_printf("Breakpoint %d at "
+				   kdb_bfd_vma_fmt " cleared\n",
+				   i, bp->bp_addr);
+
+			bp->bp_addr = 0;
+			bp->bp_free = 1;
+
+			break;
+		case KDBCMD_BE:
+			bp->bp_enabled = 1;
+
+			kdb_printf("Breakpoint %d at "
+				   kdb_bfd_vma_fmt " enabled",
+				   i, bp->bp_addr);
+
+			kdb_printf("\n");
+			break;
+		case KDBCMD_BD:
+			if (!bp->bp_enabled)
+				break;
+
+			bp->bp_enabled = 0;
+
+			kdb_printf("Breakpoint %d at "
+				   kdb_bfd_vma_fmt " disabled\n",
+				   i, bp->bp_addr);
+
+			break;
+		}
+		if (bp->bp_delay && (cmd == KDBCMD_BC || cmd == KDBCMD_BD)) {
+			bp->bp_delay = 0;
+			KDB_STATE_CLEAR(SSBPT);
+		}
+	}
+
+	return (!done) ? KDB_BPTNOTFOUND : 0;
+}
+
+/*
+ * kdb_ss
+ *
+ *	Process the 'ss' (Single Step) command.
+ *
+ *	ss
+ *
+ * Parameters:
+ *	argc	Argument count
+ *	argv	Argument vector
+ * Outputs:
+ *	None.
+ * Returns:
+ *	KDB_CMD_SS for success, a kdb error if failure.
+ * Locking:
+ *	None.
+ * Remarks:
+ *
+ *	Set the arch specific option to trigger a debug trap after the next
+ *	instruction.
+ */
+
+static int kdb_ss(int argc, const char **argv)
+{
+	if (argc != 0)
+		return KDB_ARGCOUNT;
+	/*
+	 * Set trace flag and go.
+	 */
+	KDB_STATE_SET(DOING_SS);
+	return KDB_CMD_SS;
+}
+
+static kdbtab_t bptab[] = {
+	{	.name = "bp",
+		.func = kdb_bp,
+		.usage = "[<vaddr>]",
+		.help = "Set/Display breakpoints",
+		.flags = KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS,
+	},
+	{	.name = "bl",
+		.func = kdb_bp,
+		.usage = "[<vaddr>]",
+		.help = "Display breakpoints",
+		.flags = KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS,
+	},
+	{	.name = "bc",
+		.func = kdb_bc,
+		.usage = "<bpnum>",
+		.help = "Clear Breakpoint",
+		.flags = KDB_ENABLE_FLOW_CTRL,
+	},
+	{	.name = "be",
+		.func = kdb_bc,
+		.usage = "<bpnum>",
+		.help = "Enable Breakpoint",
+		.flags = KDB_ENABLE_FLOW_CTRL,
+	},
+	{	.name = "bd",
+		.func = kdb_bc,
+		.usage = "<bpnum>",
+		.help = "Disable Breakpoint",
+		.flags = KDB_ENABLE_FLOW_CTRL,
+	},
+	{	.name = "ss",
+		.func = kdb_ss,
+		.usage = "",
+		.help = "Single Step",
+		.minlen = 1,
+		.flags = KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS,
+	},
+};
+
+static kdbtab_t bphcmd = {
+	.name = "bph",
+	.func = kdb_bp,
+	.usage = "[<vaddr>]",
+	.help = "[datar [length]|dataw [length]]   Set hw brk",
+	.flags = KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS,
+};
+
+/* Initialize the breakpoint table and register	breakpoint commands. */
+
+void __init kdb_initbptab(void)
+{
+	int i;
+	kdb_bp_t *bp;
+
+	/*
+	 * First time initialization.
+	 */
+	memset(&kdb_breakpoints, '\0', sizeof(kdb_breakpoints));
+
+	for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++)
+		bp->bp_free = 1;
+
+	kdb_register_table(bptab, ARRAY_SIZE(bptab));
+	if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)
+		kdb_register_table(&bphcmd, 1);
+}
diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
new file mode 100644
index 000000000..10b454554
--- /dev/null
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -0,0 +1,221 @@
+/*
+ * Kernel Debugger Architecture Independent Stack Traceback
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 1999-2004 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ */
+
+#include <linux/ctype.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/debug.h>
+#include <linux/kdb.h>
+#include <linux/nmi.h>
+#include "kdb_private.h"
+
+
+static void kdb_show_stack(struct task_struct *p, void *addr)
+{
+	kdb_trap_printk++;
+
+	if (!addr && kdb_task_has_cpu(p)) {
+		int old_lvl = console_loglevel;
+
+		console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
+		kdb_dump_stack_on_cpu(kdb_process_cpu(p));
+		console_loglevel = old_lvl;
+	} else {
+		show_stack(p, addr, KERN_EMERG);
+	}
+
+	kdb_trap_printk--;
+}
+
+/*
+ * kdb_bt
+ *
+ *	This function implements the 'bt' command.  Print a stack
+ *	traceback.
+ *
+ *	bt [<address-expression>]	(addr-exp is for alternate stacks)
+ *	btp <pid>			Kernel stack for <pid>
+ *	btt <address-expression>	Kernel stack for task structure at
+ *					<address-expression>
+ *	bta [state_chars>|A]		All useful processes, optionally
+ *					filtered by state
+ *	btc [<cpu>]			The current process on one cpu,
+ *					default is all cpus
+ *
+ *	bt <address-expression> refers to a address on the stack, that location
+ *	is assumed to contain a return address.
+ *
+ *	btt <address-expression> refers to the address of a struct task.
+ *
+ * Inputs:
+ *	argc	argument count
+ *	argv	argument vector
+ * Outputs:
+ *	None.
+ * Returns:
+ *	zero for success, a kdb diagnostic if error
+ * Locking:
+ *	none.
+ * Remarks:
+ *	Backtrack works best when the code uses frame pointers.  But even
+ *	without frame pointers we should get a reasonable trace.
+ *
+ *	mds comes in handy when examining the stack to do a manual traceback or
+ *	to get a starting point for bt <address-expression>.
+ */
+
+static int
+kdb_bt1(struct task_struct *p, const char *mask, bool btaprompt)
+{
+	char ch;
+
+	if (kdb_getarea(ch, (unsigned long)p) ||
+	    kdb_getarea(ch, (unsigned long)(p+1)-1))
+		return KDB_BADADDR;
+	if (!kdb_task_state(p, mask))
+		return 0;
+	kdb_printf("Stack traceback for pid %d\n", p->pid);
+	kdb_ps1(p);
+	kdb_show_stack(p, NULL);
+	if (btaprompt) {
+		kdb_printf("Enter <q> to end, <cr> or <space> to continue:");
+		do {
+			ch = kdb_getchar();
+		} while (!strchr("\r\n q", ch));
+		kdb_printf("\n");
+
+		/* reset the pager */
+		kdb_nextline = 1;
+
+		if (ch == 'q')
+			return 1;
+	}
+	touch_nmi_watchdog();
+	return 0;
+}
+
+static void
+kdb_bt_cpu(unsigned long cpu)
+{
+	struct task_struct *kdb_tsk;
+
+	if (cpu >= num_possible_cpus() || !cpu_online(cpu)) {
+		kdb_printf("WARNING: no process for cpu %ld\n", cpu);
+		return;
+	}
+
+	/* If a CPU failed to round up we could be here */
+	kdb_tsk = KDB_TSK(cpu);
+	if (!kdb_tsk) {
+		kdb_printf("WARNING: no task for cpu %ld\n", cpu);
+		return;
+	}
+
+	kdb_bt1(kdb_tsk, "A", false);
+}
+
+int
+kdb_bt(int argc, const char **argv)
+{
+	int diag;
+	int btaprompt = 1;
+	int nextarg;
+	unsigned long addr;
+	long offset;
+
+	/* Prompt after each proc in bta */
+	kdbgetintenv("BTAPROMPT", &btaprompt);
+
+	if (strcmp(argv[0], "bta") == 0) {
+		struct task_struct *g, *p;
+		unsigned long cpu;
+		const char *mask = argc ? argv[1] : kdbgetenv("PS");
+
+		if (argc == 0)
+			kdb_ps_suppressed();
+		/* Run the active tasks first */
+		for_each_online_cpu(cpu) {
+			p = kdb_curr_task(cpu);
+			if (kdb_bt1(p, mask, btaprompt))
+				return 0;
+		}
+		/* Now the inactive tasks */
+		for_each_process_thread(g, p) {
+			if (KDB_FLAG(CMD_INTERRUPT))
+				return 0;
+			if (task_curr(p))
+				continue;
+			if (kdb_bt1(p, mask, btaprompt))
+				return 0;
+		}
+	} else if (strcmp(argv[0], "btp") == 0) {
+		struct task_struct *p;
+		unsigned long pid;
+		if (argc != 1)
+			return KDB_ARGCOUNT;
+		diag = kdbgetularg((char *)argv[1], &pid);
+		if (diag)
+			return diag;
+		p = find_task_by_pid_ns(pid, &init_pid_ns);
+		if (p)
+			return kdb_bt1(p, "A", false);
+		kdb_printf("No process with pid == %ld found\n", pid);
+		return 0;
+	} else if (strcmp(argv[0], "btt") == 0) {
+		if (argc != 1)
+			return KDB_ARGCOUNT;
+		diag = kdbgetularg((char *)argv[1], &addr);
+		if (diag)
+			return diag;
+		return kdb_bt1((struct task_struct *)addr, "A", false);
+	} else if (strcmp(argv[0], "btc") == 0) {
+		unsigned long cpu = ~0;
+		if (argc > 1)
+			return KDB_ARGCOUNT;
+		if (argc == 1) {
+			diag = kdbgetularg((char *)argv[1], &cpu);
+			if (diag)
+				return diag;
+		}
+		if (cpu != ~0) {
+			kdb_bt_cpu(cpu);
+		} else {
+			/*
+			 * Recursive use of kdb_parse, do not use argv after
+			 * this point.
+			 */
+			argv = NULL;
+			kdb_printf("btc: cpu status: ");
+			kdb_parse("cpu\n");
+			for_each_online_cpu(cpu) {
+				kdb_bt_cpu(cpu);
+				touch_nmi_watchdog();
+			}
+		}
+		return 0;
+	} else {
+		if (argc) {
+			nextarg = 1;
+			diag = kdbgetaddrarg(argc, argv, &nextarg, &addr,
+					     &offset, NULL);
+			if (diag)
+				return diag;
+			kdb_show_stack(kdb_current_task, (void *)addr);
+			return 0;
+		} else {
+			return kdb_bt1(kdb_current_task, "A", false);
+		}
+	}
+
+	/* NOTREACHED */
+	return 0;
+}
diff --git a/kernel/debug/kdb/kdb_cmds b/kernel/debug/kdb/kdb_cmds
new file mode 100644
index 000000000..9834ad303
--- /dev/null
+++ b/kernel/debug/kdb/kdb_cmds
@@ -0,0 +1,31 @@
+# Initial commands for kdb, alter to suit your needs.
+# These commands are executed in kdb_init() context, no SMP, no
+# processes.  Commands that require process data (including stack or
+# registers) are not reliable this early.  set and bp commands should
+# be safe.  Global breakpoint commands affect each cpu as it is booted.
+
+# Standard debugging information for first level support, just type archkdb
+# or archkdbcpu or archkdbshort at the kdb prompt.
+
+defcmd dumpcommon "" "Common kdb debugging"
+  set BTAPROMPT 0
+  set LINES 10000
+  -summary
+  -cpu
+  -ps
+  -dmesg 600
+  -bt
+endefcmd
+
+defcmd dumpall "" "First line debugging"
+  pid R
+  -dumpcommon
+  -bta
+endefcmd
+
+defcmd dumpcpu "" "Same as dumpall but only tasks on cpus"
+  pid R
+  -dumpcommon
+  -btc
+endefcmd
+
diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c
new file mode 100644
index 000000000..e91fc3e4e
--- /dev/null
+++ b/kernel/debug/kdb/kdb_debugger.c
@@ -0,0 +1,176 @@
+/*
+ * Created by: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+#include <linux/kdebug.h>
+#include <linux/export.h>
+#include <linux/hardirq.h>
+#include "kdb_private.h"
+#include "../debug_core.h"
+
+/*
+ * KDB interface to KGDB internals
+ */
+get_char_func kdb_poll_funcs[] = {
+	dbg_io_get_char,
+	NULL,
+	NULL,
+	NULL,
+	NULL,
+	NULL,
+};
+EXPORT_SYMBOL_GPL(kdb_poll_funcs);
+
+int kdb_poll_idx = 1;
+EXPORT_SYMBOL_GPL(kdb_poll_idx);
+
+static struct kgdb_state *kdb_ks;
+
+int kdb_common_init_state(struct kgdb_state *ks)
+{
+	kdb_initial_cpu = atomic_read(&kgdb_active);
+	kdb_current_task = kgdb_info[ks->cpu].task;
+	kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
+	return 0;
+}
+
+int kdb_common_deinit_state(void)
+{
+	kdb_initial_cpu = -1;
+	kdb_current_task = NULL;
+	kdb_current_regs = NULL;
+	return 0;
+}
+
+int kdb_stub(struct kgdb_state *ks)
+{
+	int error = 0;
+	kdb_bp_t *bp;
+	unsigned long addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
+	kdb_reason_t reason = KDB_REASON_OOPS;
+	kdb_dbtrap_t db_result = KDB_DB_NOBPT;
+	int i;
+
+	kdb_ks = ks;
+	if (KDB_STATE(REENTRY)) {
+		reason = KDB_REASON_SWITCH;
+		KDB_STATE_CLEAR(REENTRY);
+		addr = instruction_pointer(ks->linux_regs);
+	}
+	ks->pass_exception = 0;
+	if (atomic_read(&kgdb_setting_breakpoint))
+		reason = KDB_REASON_KEYBOARD;
+
+	if (ks->err_code == KDB_REASON_SYSTEM_NMI && ks->signo == SIGTRAP)
+		reason = KDB_REASON_SYSTEM_NMI;
+
+	else if (in_nmi())
+		reason = KDB_REASON_NMI;
+
+	for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
+		if ((bp->bp_enabled) && (bp->bp_addr == addr)) {
+			reason = KDB_REASON_BREAK;
+			db_result = KDB_DB_BPT;
+			if (addr != instruction_pointer(ks->linux_regs))
+				kgdb_arch_set_pc(ks->linux_regs, addr);
+			break;
+		}
+	}
+	if (reason == KDB_REASON_BREAK || reason == KDB_REASON_SWITCH) {
+		for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
+			if (bp->bp_free)
+				continue;
+			if (bp->bp_addr == addr) {
+				bp->bp_delay = 1;
+				bp->bp_delayed = 1;
+	/*
+	 * SSBPT is set when the kernel debugger must single step a
+	 * task in order to re-establish an instruction breakpoint
+	 * which uses the instruction replacement mechanism.  It is
+	 * cleared by any action that removes the need to single-step
+	 * the breakpoint.
+	 */
+				reason = KDB_REASON_BREAK;
+				db_result = KDB_DB_BPT;
+				KDB_STATE_SET(SSBPT);
+				break;
+			}
+		}
+	}
+
+	if (reason != KDB_REASON_BREAK && ks->ex_vector == 0 &&
+		ks->signo == SIGTRAP) {
+		reason = KDB_REASON_SSTEP;
+		db_result = KDB_DB_BPT;
+	}
+	/* Set initial kdb state variables */
+	KDB_STATE_CLEAR(KGDB_TRANS);
+	kdb_common_init_state(ks);
+	/* Remove any breakpoints as needed by kdb and clear single step */
+	kdb_bp_remove();
+	KDB_STATE_CLEAR(DOING_SS);
+	KDB_STATE_SET(PAGER);
+	if (ks->err_code == DIE_OOPS || reason == KDB_REASON_OOPS) {
+		ks->pass_exception = 1;
+		KDB_FLAG_SET(CATASTROPHIC);
+	}
+	/* set CATASTROPHIC if the system contains unresponsive processors */
+	for_each_online_cpu(i)
+		if (!kgdb_info[i].enter_kgdb)
+			KDB_FLAG_SET(CATASTROPHIC);
+	if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) {
+		KDB_STATE_CLEAR(SSBPT);
+		KDB_STATE_CLEAR(DOING_SS);
+	} else {
+		/* Start kdb main loop */
+		error = kdb_main_loop(KDB_REASON_ENTER, reason,
+				      ks->err_code, db_result, ks->linux_regs);
+	}
+	/*
+	 * Upon exit from the kdb main loop setup break points and restart
+	 * the system based on the requested continue state
+	 */
+	kdb_common_deinit_state();
+	KDB_STATE_CLEAR(PAGER);
+	if (error == KDB_CMD_KGDB) {
+		if (KDB_STATE(DOING_KGDB))
+			KDB_STATE_CLEAR(DOING_KGDB);
+		return DBG_PASS_EVENT;
+	}
+	kdb_bp_install(ks->linux_regs);
+	/* Set the exit state to a single step or a continue */
+	if (KDB_STATE(DOING_SS))
+		gdbstub_state(ks, "s");
+	else
+		gdbstub_state(ks, "c");
+
+	KDB_FLAG_CLEAR(CATASTROPHIC);
+
+	/* Invoke arch specific exception handling prior to system resume */
+	kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, "e");
+	if (ks->pass_exception)
+		kgdb_info[ks->cpu].ret_state = 1;
+	if (error == KDB_CMD_CPU) {
+		KDB_STATE_SET(REENTRY);
+		/*
+		 * Force clear the single step bit because kdb emulates this
+		 * differently vs the gdbstub
+		 */
+		kgdb_single_step = 0;
+		return DBG_SWITCH_CPU_EVENT;
+	}
+	return kgdb_info[ks->cpu].ret_state;
+}
+
+void kdb_gdb_state_pass(char *buf)
+{
+	gdbstub_state(kdb_ks, buf);
+}
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
new file mode 100644
index 000000000..67d3c48a1
--- /dev/null
+++ b/kernel/debug/kdb/kdb_io.c
@@ -0,0 +1,869 @@
+/*
+ * Kernel Debugger Architecture Independent Console I/O handler
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 1999-2006 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ */
+
+#include <linux/types.h>
+#include <linux/ctype.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/kdev_t.h>
+#include <linux/console.h>
+#include <linux/string.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/nmi.h>
+#include <linux/delay.h>
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+#include <linux/kallsyms.h>
+#include "kdb_private.h"
+
+#define CMD_BUFLEN 256
+char kdb_prompt_str[CMD_BUFLEN];
+
+int kdb_trap_printk;
+int kdb_printf_cpu = -1;
+
+static int kgdb_transition_check(char *buffer)
+{
+	if (buffer[0] != '+' && buffer[0] != '$') {
+		KDB_STATE_SET(KGDB_TRANS);
+		kdb_printf("%s", buffer);
+	} else {
+		int slen = strlen(buffer);
+		if (slen > 3 && buffer[slen - 3] == '#') {
+			kdb_gdb_state_pass(buffer);
+			strcpy(buffer, "kgdb");
+			KDB_STATE_SET(DOING_KGDB);
+			return 1;
+		}
+	}
+	return 0;
+}
+
+/**
+ * kdb_handle_escape() - validity check on an accumulated escape sequence.
+ * @buf:	Accumulated escape characters to be examined. Note that buf
+ *		is not a string, it is an array of characters and need not be
+ *		nil terminated.
+ * @sz:		Number of accumulated escape characters.
+ *
+ * Return: -1 if the escape sequence is unwanted, 0 if it is incomplete,
+ * otherwise it returns a mapped key value to pass to the upper layers.
+ */
+static int kdb_handle_escape(char *buf, size_t sz)
+{
+	char *lastkey = buf + sz - 1;
+
+	switch (sz) {
+	case 1:
+		if (*lastkey == '\e')
+			return 0;
+		break;
+
+	case 2: /* \e<something> */
+		if (*lastkey == '[')
+			return 0;
+		break;
+
+	case 3:
+		switch (*lastkey) {
+		case 'A': /* \e[A, up arrow */
+			return 16;
+		case 'B': /* \e[B, down arrow */
+			return 14;
+		case 'C': /* \e[C, right arrow */
+			return 6;
+		case 'D': /* \e[D, left arrow */
+			return 2;
+		case '1': /* \e[<1,3,4>], may be home, del, end */
+		case '3':
+		case '4':
+			return 0;
+		}
+		break;
+
+	case 4:
+		if (*lastkey == '~') {
+			switch (buf[2]) {
+			case '1': /* \e[1~, home */
+				return 1;
+			case '3': /* \e[3~, del */
+				return 4;
+			case '4': /* \e[4~, end */
+				return 5;
+			}
+		}
+		break;
+	}
+
+	return -1;
+}
+
+/**
+ * kdb_getchar() - Read a single character from a kdb console (or consoles).
+ *
+ * Other than polling the various consoles that are currently enabled,
+ * most of the work done in this function is dealing with escape sequences.
+ *
+ * An escape key could be the start of a vt100 control sequence such as \e[D
+ * (left arrow) or it could be a character in its own right.  The standard
+ * method for detecting the difference is to wait for 2 seconds to see if there
+ * are any other characters.  kdb is complicated by the lack of a timer service
+ * (interrupts are off), by multiple input sources. Escape sequence processing
+ * has to be done as states in the polling loop.
+ *
+ * Return: The key pressed or a control code derived from an escape sequence.
+ */
+char kdb_getchar(void)
+{
+#define ESCAPE_UDELAY 1000
+#define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
+	char buf[4];	/* longest vt100 escape sequence is 4 bytes */
+	char *pbuf = buf;
+	int escape_delay = 0;
+	get_char_func *f, *f_prev = NULL;
+	int key;
+
+	for (f = &kdb_poll_funcs[0]; ; ++f) {
+		if (*f == NULL) {
+			/* Reset NMI watchdog once per poll loop */
+			touch_nmi_watchdog();
+			f = &kdb_poll_funcs[0];
+		}
+
+		key = (*f)();
+		if (key == -1) {
+			if (escape_delay) {
+				udelay(ESCAPE_UDELAY);
+				if (--escape_delay == 0)
+					return '\e';
+			}
+			continue;
+		}
+
+		/*
+		 * When the first character is received (or we get a change
+		 * input source) we set ourselves up to handle an escape
+		 * sequences (just in case).
+		 */
+		if (f_prev != f) {
+			f_prev = f;
+			pbuf = buf;
+			escape_delay = ESCAPE_DELAY;
+		}
+
+		*pbuf++ = key;
+		key = kdb_handle_escape(buf, pbuf - buf);
+		if (key < 0) /* no escape sequence; return best character */
+			return buf[pbuf - buf == 2 ? 1 : 0];
+		if (key > 0)
+			return key;
+	}
+
+	unreachable();
+}
+
+/*
+ * kdb_read
+ *
+ *	This function reads a string of characters, terminated by
+ *	a newline, or by reaching the end of the supplied buffer,
+ *	from the current kernel debugger console device.
+ * Parameters:
+ *	buffer	- Address of character buffer to receive input characters.
+ *	bufsize - size, in bytes, of the character buffer
+ * Returns:
+ *	Returns a pointer to the buffer containing the received
+ *	character string.  This string will be terminated by a
+ *	newline character.
+ * Locking:
+ *	No locks are required to be held upon entry to this
+ *	function.  It is not reentrant - it relies on the fact
+ *	that while kdb is running on only one "master debug" cpu.
+ * Remarks:
+ *	The buffer size must be >= 2.
+ */
+
+static char *kdb_read(char *buffer, size_t bufsize)
+{
+	char *cp = buffer;
+	char *bufend = buffer+bufsize-2;	/* Reserve space for newline
+						 * and null byte */
+	char *lastchar;
+	char *p_tmp;
+	char tmp;
+	static char tmpbuffer[CMD_BUFLEN];
+	int len = strlen(buffer);
+	int len_tmp;
+	int tab = 0;
+	int count;
+	int i;
+	int diag, dtab_count;
+	int key, buf_size, ret;
+
+
+	diag = kdbgetintenv("DTABCOUNT", &dtab_count);
+	if (diag)
+		dtab_count = 30;
+
+	if (len > 0) {
+		cp += len;
+		if (*(buffer+len-1) == '\n')
+			cp--;
+	}
+
+	lastchar = cp;
+	*cp = '\0';
+	kdb_printf("%s", buffer);
+poll_again:
+	key = kdb_getchar();
+	if (key != 9)
+		tab = 0;
+	switch (key) {
+	case 8: /* backspace */
+		if (cp > buffer) {
+			if (cp < lastchar) {
+				memcpy(tmpbuffer, cp, lastchar - cp);
+				memcpy(cp-1, tmpbuffer, lastchar - cp);
+			}
+			*(--lastchar) = '\0';
+			--cp;
+			kdb_printf("\b%s \r", cp);
+			tmp = *cp;
+			*cp = '\0';
+			kdb_printf(kdb_prompt_str);
+			kdb_printf("%s", buffer);
+			*cp = tmp;
+		}
+		break;
+	case 13: /* enter */
+		*lastchar++ = '\n';
+		*lastchar++ = '\0';
+		if (!KDB_STATE(KGDB_TRANS)) {
+			KDB_STATE_SET(KGDB_TRANS);
+			kdb_printf("%s", buffer);
+		}
+		kdb_printf("\n");
+		return buffer;
+	case 4: /* Del */
+		if (cp < lastchar) {
+			memcpy(tmpbuffer, cp+1, lastchar - cp - 1);
+			memcpy(cp, tmpbuffer, lastchar - cp - 1);
+			*(--lastchar) = '\0';
+			kdb_printf("%s \r", cp);
+			tmp = *cp;
+			*cp = '\0';
+			kdb_printf(kdb_prompt_str);
+			kdb_printf("%s", buffer);
+			*cp = tmp;
+		}
+		break;
+	case 1: /* Home */
+		if (cp > buffer) {
+			kdb_printf("\r");
+			kdb_printf(kdb_prompt_str);
+			cp = buffer;
+		}
+		break;
+	case 5: /* End */
+		if (cp < lastchar) {
+			kdb_printf("%s", cp);
+			cp = lastchar;
+		}
+		break;
+	case 2: /* Left */
+		if (cp > buffer) {
+			kdb_printf("\b");
+			--cp;
+		}
+		break;
+	case 14: /* Down */
+		memset(tmpbuffer, ' ',
+		       strlen(kdb_prompt_str) + (lastchar-buffer));
+		*(tmpbuffer+strlen(kdb_prompt_str) +
+		  (lastchar-buffer)) = '\0';
+		kdb_printf("\r%s\r", tmpbuffer);
+		*lastchar = (char)key;
+		*(lastchar+1) = '\0';
+		return lastchar;
+	case 6: /* Right */
+		if (cp < lastchar) {
+			kdb_printf("%c", *cp);
+			++cp;
+		}
+		break;
+	case 16: /* Up */
+		memset(tmpbuffer, ' ',
+		       strlen(kdb_prompt_str) + (lastchar-buffer));
+		*(tmpbuffer+strlen(kdb_prompt_str) +
+		  (lastchar-buffer)) = '\0';
+		kdb_printf("\r%s\r", tmpbuffer);
+		*lastchar = (char)key;
+		*(lastchar+1) = '\0';
+		return lastchar;
+	case 9: /* Tab */
+		if (tab < 2)
+			++tab;
+		p_tmp = buffer;
+		while (*p_tmp == ' ')
+			p_tmp++;
+		if (p_tmp > cp)
+			break;
+		memcpy(tmpbuffer, p_tmp, cp-p_tmp);
+		*(tmpbuffer + (cp-p_tmp)) = '\0';
+		p_tmp = strrchr(tmpbuffer, ' ');
+		if (p_tmp)
+			++p_tmp;
+		else
+			p_tmp = tmpbuffer;
+		len = strlen(p_tmp);
+		buf_size = sizeof(tmpbuffer) - (p_tmp - tmpbuffer);
+		count = kallsyms_symbol_complete(p_tmp, buf_size);
+		if (tab == 2 && count > 0) {
+			kdb_printf("\n%d symbols are found.", count);
+			if (count > dtab_count) {
+				count = dtab_count;
+				kdb_printf(" But only first %d symbols will"
+					   " be printed.\nYou can change the"
+					   " environment variable DTABCOUNT.",
+					   count);
+			}
+			kdb_printf("\n");
+			for (i = 0; i < count; i++) {
+				ret = kallsyms_symbol_next(p_tmp, i, buf_size);
+				if (WARN_ON(!ret))
+					break;
+				if (ret != -E2BIG)
+					kdb_printf("%s ", p_tmp);
+				else
+					kdb_printf("%s... ", p_tmp);
+				*(p_tmp + len) = '\0';
+			}
+			if (i >= dtab_count)
+				kdb_printf("...");
+			kdb_printf("\n");
+			kdb_printf(kdb_prompt_str);
+			kdb_printf("%s", buffer);
+		} else if (tab != 2 && count > 0) {
+			len_tmp = strlen(p_tmp);
+			strncpy(p_tmp+len_tmp, cp, lastchar-cp+1);
+			len_tmp = strlen(p_tmp);
+			strncpy(cp, p_tmp+len, len_tmp-len + 1);
+			len = len_tmp - len;
+			kdb_printf("%s", cp);
+			cp += len;
+			lastchar += len;
+		}
+		kdb_nextline = 1; /* reset output line number */
+		break;
+	default:
+		if (key >= 32 && lastchar < bufend) {
+			if (cp < lastchar) {
+				memcpy(tmpbuffer, cp, lastchar - cp);
+				memcpy(cp+1, tmpbuffer, lastchar - cp);
+				*++lastchar = '\0';
+				*cp = key;
+				kdb_printf("%s\r", cp);
+				++cp;
+				tmp = *cp;
+				*cp = '\0';
+				kdb_printf(kdb_prompt_str);
+				kdb_printf("%s", buffer);
+				*cp = tmp;
+			} else {
+				*++lastchar = '\0';
+				*cp++ = key;
+				/* The kgdb transition check will hide
+				 * printed characters if we think that
+				 * kgdb is connecting, until the check
+				 * fails */
+				if (!KDB_STATE(KGDB_TRANS)) {
+					if (kgdb_transition_check(buffer))
+						return buffer;
+				} else {
+					kdb_printf("%c", key);
+				}
+			}
+			/* Special escape to kgdb */
+			if (lastchar - buffer >= 5 &&
+			    strcmp(lastchar - 5, "$?#3f") == 0) {
+				kdb_gdb_state_pass(lastchar - 5);
+				strcpy(buffer, "kgdb");
+				KDB_STATE_SET(DOING_KGDB);
+				return buffer;
+			}
+			if (lastchar - buffer >= 11 &&
+			    strcmp(lastchar - 11, "$qSupported") == 0) {
+				kdb_gdb_state_pass(lastchar - 11);
+				strcpy(buffer, "kgdb");
+				KDB_STATE_SET(DOING_KGDB);
+				return buffer;
+			}
+		}
+		break;
+	}
+	goto poll_again;
+}
+
+/*
+ * kdb_getstr
+ *
+ *	Print the prompt string and read a command from the
+ *	input device.
+ *
+ * Parameters:
+ *	buffer	Address of buffer to receive command
+ *	bufsize Size of buffer in bytes
+ *	prompt	Pointer to string to use as prompt string
+ * Returns:
+ *	Pointer to command buffer.
+ * Locking:
+ *	None.
+ * Remarks:
+ *	For SMP kernels, the processor number will be
+ *	substituted for %d, %x or %o in the prompt.
+ */
+
+char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
+{
+	if (prompt && kdb_prompt_str != prompt)
+		strscpy(kdb_prompt_str, prompt, CMD_BUFLEN);
+	kdb_printf(kdb_prompt_str);
+	kdb_nextline = 1;	/* Prompt and input resets line number */
+	return kdb_read(buffer, bufsize);
+}
+
+/*
+ * kdb_input_flush
+ *
+ *	Get rid of any buffered console input.
+ *
+ * Parameters:
+ *	none
+ * Returns:
+ *	nothing
+ * Locking:
+ *	none
+ * Remarks:
+ *	Call this function whenever you want to flush input.  If there is any
+ *	outstanding input, it ignores all characters until there has been no
+ *	data for approximately 1ms.
+ */
+
+static void kdb_input_flush(void)
+{
+	get_char_func *f;
+	int res;
+	int flush_delay = 1;
+	while (flush_delay) {
+		flush_delay--;
+empty:
+		touch_nmi_watchdog();
+		for (f = &kdb_poll_funcs[0]; *f; ++f) {
+			res = (*f)();
+			if (res != -1) {
+				flush_delay = 1;
+				goto empty;
+			}
+		}
+		if (flush_delay)
+			mdelay(1);
+	}
+}
+
+/*
+ * kdb_printf
+ *
+ *	Print a string to the output device(s).
+ *
+ * Parameters:
+ *	printf-like format and optional args.
+ * Returns:
+ *	0
+ * Locking:
+ *	None.
+ * Remarks:
+ *	use 'kdbcons->write()' to avoid polluting 'log_buf' with
+ *	kdb output.
+ *
+ *  If the user is doing a cmd args | grep srch
+ *  then kdb_grepping_flag is set.
+ *  In that case we need to accumulate full lines (ending in \n) before
+ *  searching for the pattern.
+ */
+
+static char kdb_buffer[256];	/* A bit too big to go on stack */
+static char *next_avail = kdb_buffer;
+static int  size_avail;
+static int  suspend_grep;
+
+/*
+ * search arg1 to see if it contains arg2
+ * (kdmain.c provides flags for ^pat and pat$)
+ *
+ * return 1 for found, 0 for not found
+ */
+static int kdb_search_string(char *searched, char *searchfor)
+{
+	char firstchar, *cp;
+	int len1, len2;
+
+	/* not counting the newline at the end of "searched" */
+	len1 = strlen(searched)-1;
+	len2 = strlen(searchfor);
+	if (len1 < len2)
+		return 0;
+	if (kdb_grep_leading && kdb_grep_trailing && len1 != len2)
+		return 0;
+	if (kdb_grep_leading) {
+		if (!strncmp(searched, searchfor, len2))
+			return 1;
+	} else if (kdb_grep_trailing) {
+		if (!strncmp(searched+len1-len2, searchfor, len2))
+			return 1;
+	} else {
+		firstchar = *searchfor;
+		cp = searched;
+		while ((cp = strchr(cp, firstchar))) {
+			if (!strncmp(cp, searchfor, len2))
+				return 1;
+			cp++;
+		}
+	}
+	return 0;
+}
+
+static void kdb_msg_write(const char *msg, int msg_len)
+{
+	struct console *c;
+	const char *cp;
+	int len;
+
+	if (msg_len == 0)
+		return;
+
+	cp = msg;
+	len = msg_len;
+
+	while (len--) {
+		dbg_io_ops->write_char(*cp);
+		cp++;
+	}
+
+	for_each_console(c) {
+		if (!(c->flags & CON_ENABLED))
+			continue;
+		if (c == dbg_io_ops->cons)
+			continue;
+		/*
+		 * Set oops_in_progress to encourage the console drivers to
+		 * disregard their internal spin locks: in the current calling
+		 * context the risk of deadlock is a bigger problem than risks
+		 * due to re-entering the console driver. We operate directly on
+		 * oops_in_progress rather than using bust_spinlocks() because
+		 * the calls bust_spinlocks() makes on exit are not appropriate
+		 * for this calling context.
+		 */
+		++oops_in_progress;
+		c->write(c, msg, msg_len);
+		--oops_in_progress;
+		touch_nmi_watchdog();
+	}
+}
+
+int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
+{
+	int diag;
+	int linecount;
+	int colcount;
+	int logging, saved_loglevel = 0;
+	int retlen = 0;
+	int fnd, len;
+	int this_cpu, old_cpu;
+	char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
+	char *moreprompt = "more> ";
+	unsigned long flags;
+
+	/* Serialize kdb_printf if multiple cpus try to write at once.
+	 * But if any cpu goes recursive in kdb, just print the output,
+	 * even if it is interleaved with any other text.
+	 */
+	local_irq_save(flags);
+	this_cpu = smp_processor_id();
+	for (;;) {
+		old_cpu = cmpxchg(&kdb_printf_cpu, -1, this_cpu);
+		if (old_cpu == -1 || old_cpu == this_cpu)
+			break;
+
+		cpu_relax();
+	}
+
+	diag = kdbgetintenv("LINES", &linecount);
+	if (diag || linecount <= 1)
+		linecount = 24;
+
+	diag = kdbgetintenv("COLUMNS", &colcount);
+	if (diag || colcount <= 1)
+		colcount = 80;
+
+	diag = kdbgetintenv("LOGGING", &logging);
+	if (diag)
+		logging = 0;
+
+	if (!kdb_grepping_flag || suspend_grep) {
+		/* normally, every vsnprintf starts a new buffer */
+		next_avail = kdb_buffer;
+		size_avail = sizeof(kdb_buffer);
+	}
+	vsnprintf(next_avail, size_avail, fmt, ap);
+
+	/*
+	 * If kdb_parse() found that the command was cmd xxx | grep yyy
+	 * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
+	 *
+	 * Accumulate the print data up to a newline before searching it.
+	 * (vsnprintf does null-terminate the string that it generates)
+	 */
+
+	/* skip the search if prints are temporarily unconditional */
+	if (!suspend_grep && kdb_grepping_flag) {
+		cp = strchr(kdb_buffer, '\n');
+		if (!cp) {
+			/*
+			 * Special cases that don't end with newlines
+			 * but should be written without one:
+			 *   The "[nn]kdb> " prompt should
+			 *   appear at the front of the buffer.
+			 *
+			 *   The "[nn]more " prompt should also be
+			 *     (MOREPROMPT -> moreprompt)
+			 *   written *   but we print that ourselves,
+			 *   we set the suspend_grep flag to make
+			 *   it unconditional.
+			 *
+			 */
+			if (next_avail == kdb_buffer) {
+				/*
+				 * these should occur after a newline,
+				 * so they will be at the front of the
+				 * buffer
+				 */
+				cp2 = kdb_buffer;
+				len = strlen(kdb_prompt_str);
+				if (!strncmp(cp2, kdb_prompt_str, len)) {
+					/*
+					 * We're about to start a new
+					 * command, so we can go back
+					 * to normal mode.
+					 */
+					kdb_grepping_flag = 0;
+					goto kdb_printit;
+				}
+			}
+			/* no newline; don't search/write the buffer
+			   until one is there */
+			len = strlen(kdb_buffer);
+			next_avail = kdb_buffer + len;
+			size_avail = sizeof(kdb_buffer) - len;
+			goto kdb_print_out;
+		}
+
+		/*
+		 * The newline is present; print through it or discard
+		 * it, depending on the results of the search.
+		 */
+		cp++;	 	     /* to byte after the newline */
+		replaced_byte = *cp; /* remember what/where it was */
+		cphold = cp;
+		*cp = '\0';	     /* end the string for our search */
+
+		/*
+		 * We now have a newline at the end of the string
+		 * Only continue with this output if it contains the
+		 * search string.
+		 */
+		fnd = kdb_search_string(kdb_buffer, kdb_grep_string);
+		if (!fnd) {
+			/*
+			 * At this point the complete line at the start
+			 * of kdb_buffer can be discarded, as it does
+			 * not contain what the user is looking for.
+			 * Shift the buffer left.
+			 */
+			*cphold = replaced_byte;
+			strcpy(kdb_buffer, cphold);
+			len = strlen(kdb_buffer);
+			next_avail = kdb_buffer + len;
+			size_avail = sizeof(kdb_buffer) - len;
+			goto kdb_print_out;
+		}
+		if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH) {
+			/*
+			 * This was a interactive search (using '/' at more
+			 * prompt) and it has completed. Replace the \0 with
+			 * its original value to ensure multi-line strings
+			 * are handled properly, and return to normal mode.
+			 */
+			*cphold = replaced_byte;
+			kdb_grepping_flag = 0;
+		}
+		/*
+		 * at this point the string is a full line and
+		 * should be printed, up to the null.
+		 */
+	}
+kdb_printit:
+
+	/*
+	 * Write to all consoles.
+	 */
+	retlen = strlen(kdb_buffer);
+	cp = (char *) printk_skip_headers(kdb_buffer);
+	if (!dbg_kdb_mode && kgdb_connected)
+		gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
+	else
+		kdb_msg_write(cp, retlen - (cp - kdb_buffer));
+
+	if (logging) {
+		saved_loglevel = console_loglevel;
+		console_loglevel = CONSOLE_LOGLEVEL_SILENT;
+		if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK)
+			printk("%s", kdb_buffer);
+		else
+			pr_info("%s", kdb_buffer);
+	}
+
+	if (KDB_STATE(PAGER)) {
+		/*
+		 * Check printed string to decide how to bump the
+		 * kdb_nextline to control when the more prompt should
+		 * show up.
+		 */
+		int got = 0;
+		len = retlen;
+		while (len--) {
+			if (kdb_buffer[len] == '\n') {
+				kdb_nextline++;
+				got = 0;
+			} else if (kdb_buffer[len] == '\r') {
+				got = 0;
+			} else {
+				got++;
+			}
+		}
+		kdb_nextline += got / (colcount + 1);
+	}
+
+	/* check for having reached the LINES number of printed lines */
+	if (kdb_nextline >= linecount) {
+		char ch;
+
+		/* Watch out for recursion here.  Any routine that calls
+		 * kdb_printf will come back through here.  And kdb_read
+		 * uses kdb_printf to echo on serial consoles ...
+		 */
+		kdb_nextline = 1;	/* In case of recursion */
+
+		/*
+		 * Pause until cr.
+		 */
+		moreprompt = kdbgetenv("MOREPROMPT");
+		if (moreprompt == NULL)
+			moreprompt = "more> ";
+
+		kdb_input_flush();
+		kdb_msg_write(moreprompt, strlen(moreprompt));
+
+		if (logging)
+			printk("%s", moreprompt);
+
+		ch = kdb_getchar();
+		kdb_nextline = 1;	/* Really set output line 1 */
+
+		/* empty and reset the buffer: */
+		kdb_buffer[0] = '\0';
+		next_avail = kdb_buffer;
+		size_avail = sizeof(kdb_buffer);
+		if ((ch == 'q') || (ch == 'Q')) {
+			/* user hit q or Q */
+			KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
+			KDB_STATE_CLEAR(PAGER);
+			/* end of command output; back to normal mode */
+			kdb_grepping_flag = 0;
+			kdb_printf("\n");
+		} else if (ch == ' ') {
+			kdb_printf("\r");
+			suspend_grep = 1; /* for this recursion */
+		} else if (ch == '\n' || ch == '\r') {
+			kdb_nextline = linecount - 1;
+			kdb_printf("\r");
+			suspend_grep = 1; /* for this recursion */
+		} else if (ch == '/' && !kdb_grepping_flag) {
+			kdb_printf("\r");
+			kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
+				   kdbgetenv("SEARCHPROMPT") ?: "search> ");
+			*strchrnul(kdb_grep_string, '\n') = '\0';
+			kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
+			suspend_grep = 1; /* for this recursion */
+		} else if (ch) {
+			/* user hit something unexpected */
+			suspend_grep = 1; /* for this recursion */
+			if (ch != '/')
+				kdb_printf(
+				    "\nOnly 'q', 'Q' or '/' are processed at "
+				    "more prompt, input ignored\n");
+			else
+				kdb_printf("\n'/' cannot be used during | "
+					   "grep filtering, input ignored\n");
+		} else if (kdb_grepping_flag) {
+			/* user hit enter */
+			suspend_grep = 1; /* for this recursion */
+			kdb_printf("\n");
+		}
+		kdb_input_flush();
+	}
+
+	/*
+	 * For grep searches, shift the printed string left.
+	 *  replaced_byte contains the character that was overwritten with
+	 *  the terminating null, and cphold points to the null.
+	 * Then adjust the notion of available space in the buffer.
+	 */
+	if (kdb_grepping_flag && !suspend_grep) {
+		*cphold = replaced_byte;
+		strcpy(kdb_buffer, cphold);
+		len = strlen(kdb_buffer);
+		next_avail = kdb_buffer + len;
+		size_avail = sizeof(kdb_buffer) - len;
+	}
+
+kdb_print_out:
+	suspend_grep = 0; /* end of what may have been a recursive call */
+	if (logging)
+		console_loglevel = saved_loglevel;
+	/* kdb_printf_cpu locked the code above. */
+	smp_store_release(&kdb_printf_cpu, old_cpu);
+	local_irq_restore(flags);
+	return retlen;
+}
+
+int kdb_printf(const char *fmt, ...)
+{
+	va_list ap;
+	int r;
+
+	va_start(ap, fmt);
+	r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap);
+	va_end(ap);
+
+	return r;
+}
+EXPORT_SYMBOL_GPL(kdb_printf);
diff --git a/kernel/debug/kdb/kdb_keyboard.c b/kernel/debug/kdb/kdb_keyboard.c
new file mode 100644
index 000000000..f87c750d3
--- /dev/null
+++ b/kernel/debug/kdb/kdb_keyboard.c
@@ -0,0 +1,262 @@
+/*
+ * Kernel Debugger Architecture Dependent Console I/O handler
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.
+ *
+ * Copyright (c) 1999-2006 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ */
+
+#include <linux/kdb.h>
+#include <linux/keyboard.h>
+#include <linux/ctype.h>
+#include <linux/io.h>
+
+/* Keyboard Controller Registers on normal PCs. */
+
+#define KBD_STATUS_REG		0x64	/* Status register (R) */
+#define KBD_DATA_REG		0x60	/* Keyboard data register (R/W) */
+
+/* Status Register Bits */
+
+#define KBD_STAT_OBF 		0x01	/* Keyboard output buffer full */
+#define KBD_STAT_MOUSE_OBF	0x20	/* Mouse output buffer full */
+
+static int kbd_exists;
+static int kbd_last_ret;
+
+/*
+ * Check if the keyboard controller has a keypress for us.
+ * Some parts (Enter Release, LED change) are still blocking polled here,
+ * but hopefully they are all short.
+ */
+int kdb_get_kbd_char(void)
+{
+	int scancode, scanstatus;
+	static int shift_lock;	/* CAPS LOCK state (0-off, 1-on) */
+	static int shift_key;	/* Shift next keypress */
+	static int ctrl_key;
+	u_short keychar;
+
+	if (KDB_FLAG(NO_I8042) || KDB_FLAG(NO_VT_CONSOLE) ||
+	    (inb(KBD_STATUS_REG) == 0xff && inb(KBD_DATA_REG) == 0xff)) {
+		kbd_exists = 0;
+		return -1;
+	}
+	kbd_exists = 1;
+
+	if ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
+		return -1;
+
+	/*
+	 * Fetch the scancode
+	 */
+	scancode = inb(KBD_DATA_REG);
+	scanstatus = inb(KBD_STATUS_REG);
+
+	/*
+	 * Ignore mouse events.
+	 */
+	if (scanstatus & KBD_STAT_MOUSE_OBF)
+		return -1;
+
+	/*
+	 * Ignore release, trigger on make
+	 * (except for shift keys, where we want to
+	 *  keep the shift state so long as the key is
+	 *  held down).
+	 */
+
+	if (((scancode&0x7f) == 0x2a) || ((scancode&0x7f) == 0x36)) {
+		/*
+		 * Next key may use shift table
+		 */
+		if ((scancode & 0x80) == 0)
+			shift_key = 1;
+		else
+			shift_key = 0;
+		return -1;
+	}
+
+	if ((scancode&0x7f) == 0x1d) {
+		/*
+		 * Left ctrl key
+		 */
+		if ((scancode & 0x80) == 0)
+			ctrl_key = 1;
+		else
+			ctrl_key = 0;
+		return -1;
+	}
+
+	if ((scancode & 0x80) != 0) {
+		if (scancode == 0x9c)
+			kbd_last_ret = 0;
+		return -1;
+	}
+
+	scancode &= 0x7f;
+
+	/*
+	 * Translate scancode
+	 */
+
+	if (scancode == 0x3a) {
+		/*
+		 * Toggle caps lock
+		 */
+		shift_lock ^= 1;
+
+#ifdef	KDB_BLINK_LED
+		kdb_toggleled(0x4);
+#endif
+		return -1;
+	}
+
+	if (scancode == 0x0e) {
+		/*
+		 * Backspace
+		 */
+		return 8;
+	}
+
+	/* Special Key */
+	switch (scancode) {
+	case 0xF: /* Tab */
+		return 9;
+	case 0x53: /* Del */
+		return 4;
+	case 0x47: /* Home */
+		return 1;
+	case 0x4F: /* End */
+		return 5;
+	case 0x4B: /* Left */
+		return 2;
+	case 0x48: /* Up */
+		return 16;
+	case 0x50: /* Down */
+		return 14;
+	case 0x4D: /* Right */
+		return 6;
+	}
+
+	if (scancode == 0xe0)
+		return -1;
+
+	/*
+	 * For Japanese 86/106 keyboards
+	 * 	See comment in drivers/char/pc_keyb.c.
+	 * 	- Masahiro Adegawa
+	 */
+	if (scancode == 0x73)
+		scancode = 0x59;
+	else if (scancode == 0x7d)
+		scancode = 0x7c;
+
+	if (!shift_lock && !shift_key && !ctrl_key) {
+		keychar = plain_map[scancode];
+	} else if ((shift_lock || shift_key) && key_maps[1]) {
+		keychar = key_maps[1][scancode];
+	} else if (ctrl_key && key_maps[4]) {
+		keychar = key_maps[4][scancode];
+	} else {
+		keychar = 0x0020;
+		kdb_printf("Unknown state/scancode (%d)\n", scancode);
+	}
+	keychar &= 0x0fff;
+	if (keychar == '\t')
+		keychar = ' ';
+	switch (KTYP(keychar)) {
+	case KT_LETTER:
+	case KT_LATIN:
+		if (isprint(keychar))
+			break;		/* printable characters */
+		fallthrough;
+	case KT_SPEC:
+		if (keychar == K_ENTER)
+			break;
+		fallthrough;
+	default:
+		return -1;	/* ignore unprintables */
+	}
+
+	if (scancode == 0x1c) {
+		kbd_last_ret = 1;
+		return 13;
+	}
+
+	return keychar & 0xff;
+}
+EXPORT_SYMBOL_GPL(kdb_get_kbd_char);
+
+/*
+ * Best effort cleanup of ENTER break codes on leaving KDB. Called on
+ * exiting KDB, when we know we processed an ENTER or KP ENTER scan
+ * code.
+ */
+void kdb_kbd_cleanup_state(void)
+{
+	int scancode, scanstatus;
+
+	/*
+	 * Nothing to clean up, since either
+	 * ENTER was never pressed, or has already
+	 * gotten cleaned up.
+	 */
+	if (!kbd_last_ret)
+		return;
+
+	kbd_last_ret = 0;
+	/*
+	 * Enter key. Need to absorb the break code here, lest it gets
+	 * leaked out if we exit KDB as the result of processing 'g'.
+	 *
+	 * This has several interesting implications:
+	 * + Need to handle KP ENTER, which has break code 0xe0 0x9c.
+	 * + Need to handle repeat ENTER and repeat KP ENTER. Repeats
+	 *   only get a break code at the end of the repeated
+	 *   sequence. This means we can't propagate the repeated key
+	 *   press, and must swallow it away.
+	 * + Need to handle possible PS/2 mouse input.
+	 * + Need to handle mashed keys.
+	 */
+
+	while (1) {
+		while ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
+			cpu_relax();
+
+		/*
+		 * Fetch the scancode.
+		 */
+		scancode = inb(KBD_DATA_REG);
+		scanstatus = inb(KBD_STATUS_REG);
+
+		/*
+		 * Skip mouse input.
+		 */
+		if (scanstatus & KBD_STAT_MOUSE_OBF)
+			continue;
+
+		/*
+		 * If we see 0xe0, this is either a break code for KP
+		 * ENTER, or a repeat make for KP ENTER. Either way,
+		 * since the second byte is equivalent to an ENTER,
+		 * skip the 0xe0 and try again.
+		 *
+		 * If we see 0x1c, this must be a repeat ENTER or KP
+		 * ENTER (and we swallowed 0xe0 before). Try again.
+		 *
+		 * We can also see make and break codes for other keys
+		 * mashed before or after pressing ENTER. Thus, if we
+		 * see anything other than 0x9c, we have to try again.
+		 *
+		 * Note, if you held some key as ENTER was depressed,
+		 * that break code would get leaked out.
+		 */
+		if (scancode != 0x9c)
+			continue;
+
+		return;
+	}
+}
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
new file mode 100644
index 000000000..35aa2e98a
--- /dev/null
+++ b/kernel/debug/kdb/kdb_main.c
@@ -0,0 +1,2937 @@
+/*
+ * Kernel Debugger Architecture Independent Main Code
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1999-2004 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (C) 2000 Stephane Eranian <eranian@hpl.hp.com>
+ * Xscale (R) modifications copyright (C) 2003 Intel Corporation.
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ */
+
+#include <linux/ctype.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/kmsg_dump.h>
+#include <linux/reboot.h>
+#include <linux/sched.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/stat.h>
+#include <linux/sched/debug.h>
+#include <linux/sysrq.h>
+#include <linux/smp.h>
+#include <linux/utsname.h>
+#include <linux/vmalloc.h>
+#include <linux/atomic.h>
+#include <linux/moduleparam.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/kallsyms.h>
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+#include <linux/notifier.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/nmi.h>
+#include <linux/time.h>
+#include <linux/ptrace.h>
+#include <linux/sysctl.h>
+#include <linux/cpu.h>
+#include <linux/kdebug.h>
+#include <linux/proc_fs.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include "kdb_private.h"
+
+#undef	MODULE_PARAM_PREFIX
+#define	MODULE_PARAM_PREFIX "kdb."
+
+static int kdb_cmd_enabled = CONFIG_KDB_DEFAULT_ENABLE;
+module_param_named(cmd_enable, kdb_cmd_enabled, int, 0600);
+
+char kdb_grep_string[KDB_GREP_STRLEN];
+int kdb_grepping_flag;
+EXPORT_SYMBOL(kdb_grepping_flag);
+int kdb_grep_leading;
+int kdb_grep_trailing;
+
+/*
+ * Kernel debugger state flags
+ */
+unsigned int kdb_flags;
+
+/*
+ * kdb_lock protects updates to kdb_initial_cpu.  Used to
+ * single thread processors through the kernel debugger.
+ */
+int kdb_initial_cpu = -1;	/* cpu number that owns kdb */
+int kdb_nextline = 1;
+int kdb_state;			/* General KDB state */
+
+struct task_struct *kdb_current_task;
+struct pt_regs *kdb_current_regs;
+
+const char *kdb_diemsg;
+static int kdb_go_count;
+#ifdef CONFIG_KDB_CONTINUE_CATASTROPHIC
+static unsigned int kdb_continue_catastrophic =
+	CONFIG_KDB_CONTINUE_CATASTROPHIC;
+#else
+static unsigned int kdb_continue_catastrophic;
+#endif
+
+/* kdb_cmds_head describes the available commands. */
+static LIST_HEAD(kdb_cmds_head);
+
+typedef struct _kdbmsg {
+	int	km_diag;	/* kdb diagnostic */
+	char	*km_msg;	/* Corresponding message text */
+} kdbmsg_t;
+
+#define KDBMSG(msgnum, text) \
+	{ KDB_##msgnum, text }
+
+static kdbmsg_t kdbmsgs[] = {
+	KDBMSG(NOTFOUND, "Command Not Found"),
+	KDBMSG(ARGCOUNT, "Improper argument count, see usage."),
+	KDBMSG(BADWIDTH, "Illegal value for BYTESPERWORD use 1, 2, 4 or 8, "
+	       "8 is only allowed on 64 bit systems"),
+	KDBMSG(BADRADIX, "Illegal value for RADIX use 8, 10 or 16"),
+	KDBMSG(NOTENV, "Cannot find environment variable"),
+	KDBMSG(NOENVVALUE, "Environment variable should have value"),
+	KDBMSG(NOTIMP, "Command not implemented"),
+	KDBMSG(ENVFULL, "Environment full"),
+	KDBMSG(ENVBUFFULL, "Environment buffer full"),
+	KDBMSG(TOOMANYBPT, "Too many breakpoints defined"),
+#ifdef CONFIG_CPU_XSCALE
+	KDBMSG(TOOMANYDBREGS, "More breakpoints than ibcr registers defined"),
+#else
+	KDBMSG(TOOMANYDBREGS, "More breakpoints than db registers defined"),
+#endif
+	KDBMSG(DUPBPT, "Duplicate breakpoint address"),
+	KDBMSG(BPTNOTFOUND, "Breakpoint not found"),
+	KDBMSG(BADMODE, "Invalid IDMODE"),
+	KDBMSG(BADINT, "Illegal numeric value"),
+	KDBMSG(INVADDRFMT, "Invalid symbolic address format"),
+	KDBMSG(BADREG, "Invalid register name"),
+	KDBMSG(BADCPUNUM, "Invalid cpu number"),
+	KDBMSG(BADLENGTH, "Invalid length field"),
+	KDBMSG(NOBP, "No Breakpoint exists"),
+	KDBMSG(BADADDR, "Invalid address"),
+	KDBMSG(NOPERM, "Permission denied"),
+};
+#undef KDBMSG
+
+static const int __nkdb_err = ARRAY_SIZE(kdbmsgs);
+
+
+/*
+ * Initial environment.   This is all kept static and local to
+ * this file.   We don't want to rely on the memory allocation
+ * mechanisms in the kernel, so we use a very limited allocate-only
+ * heap for new and altered environment variables.  The entire
+ * environment is limited to a fixed number of entries (add more
+ * to __env[] if required) and a fixed amount of heap (add more to
+ * KDB_ENVBUFSIZE if required).
+ */
+
+static char *__env[31] = {
+#if defined(CONFIG_SMP)
+	"PROMPT=[%d]kdb> ",
+#else
+	"PROMPT=kdb> ",
+#endif
+	"MOREPROMPT=more> ",
+	"RADIX=16",
+	"MDCOUNT=8",		/* lines of md output */
+	KDB_PLATFORM_ENV,
+	"DTABCOUNT=30",
+	"NOSECT=1",
+};
+
+static const int __nenv = ARRAY_SIZE(__env);
+
+struct task_struct *kdb_curr_task(int cpu)
+{
+	struct task_struct *p = curr_task(cpu);
+#ifdef	_TIF_MCA_INIT
+	if ((task_thread_info(p)->flags & _TIF_MCA_INIT) && KDB_TSK(cpu))
+		p = krp->p;
+#endif
+	return p;
+}
+
+/*
+ * Update the permissions flags (kdb_cmd_enabled) to match the
+ * current lockdown state.
+ *
+ * Within this function the calls to security_locked_down() are "lazy". We
+ * avoid calling them if the current value of kdb_cmd_enabled already excludes
+ * flags that might be subject to lockdown. Additionally we deliberately check
+ * the lockdown flags independently (even though read lockdown implies write
+ * lockdown) since that results in both simpler code and clearer messages to
+ * the user on first-time debugger entry.
+ *
+ * The permission masks during a read+write lockdown permits the following
+ * flags: INSPECT, SIGNAL, REBOOT (and ALWAYS_SAFE).
+ *
+ * The INSPECT commands are not blocked during lockdown because they are
+ * not arbitrary memory reads. INSPECT covers the backtrace family (sometimes
+ * forcing them to have no arguments) and lsmod. These commands do expose
+ * some kernel state but do not allow the developer seated at the console to
+ * choose what state is reported. SIGNAL and REBOOT should not be controversial,
+ * given these are allowed for root during lockdown already.
+ */
+static void kdb_check_for_lockdown(void)
+{
+	const int write_flags = KDB_ENABLE_MEM_WRITE |
+				KDB_ENABLE_REG_WRITE |
+				KDB_ENABLE_FLOW_CTRL;
+	const int read_flags = KDB_ENABLE_MEM_READ |
+			       KDB_ENABLE_REG_READ;
+
+	bool need_to_lockdown_write = false;
+	bool need_to_lockdown_read = false;
+
+	if (kdb_cmd_enabled & (KDB_ENABLE_ALL | write_flags))
+		need_to_lockdown_write =
+			security_locked_down(LOCKDOWN_DBG_WRITE_KERNEL);
+
+	if (kdb_cmd_enabled & (KDB_ENABLE_ALL | read_flags))
+		need_to_lockdown_read =
+			security_locked_down(LOCKDOWN_DBG_READ_KERNEL);
+
+	/* De-compose KDB_ENABLE_ALL if required */
+	if (need_to_lockdown_write || need_to_lockdown_read)
+		if (kdb_cmd_enabled & KDB_ENABLE_ALL)
+			kdb_cmd_enabled = KDB_ENABLE_MASK & ~KDB_ENABLE_ALL;
+
+	if (need_to_lockdown_write)
+		kdb_cmd_enabled &= ~write_flags;
+
+	if (need_to_lockdown_read)
+		kdb_cmd_enabled &= ~read_flags;
+}
+
+/*
+ * Check whether the flags of the current command, the permissions of the kdb
+ * console and the lockdown state allow a command to be run.
+ */
+static bool kdb_check_flags(kdb_cmdflags_t flags, int permissions,
+				   bool no_args)
+{
+	/* permissions comes from userspace so needs massaging slightly */
+	permissions &= KDB_ENABLE_MASK;
+	permissions |= KDB_ENABLE_ALWAYS_SAFE;
+
+	/* some commands change group when launched with no arguments */
+	if (no_args)
+		permissions |= permissions << KDB_ENABLE_NO_ARGS_SHIFT;
+
+	flags |= KDB_ENABLE_ALL;
+
+	return permissions & flags;
+}
+
+/*
+ * kdbgetenv - This function will return the character string value of
+ *	an environment variable.
+ * Parameters:
+ *	match	A character string representing an environment variable.
+ * Returns:
+ *	NULL	No environment variable matches 'match'
+ *	char*	Pointer to string value of environment variable.
+ */
+char *kdbgetenv(const char *match)
+{
+	char **ep = __env;
+	int matchlen = strlen(match);
+	int i;
+
+	for (i = 0; i < __nenv; i++) {
+		char *e = *ep++;
+
+		if (!e)
+			continue;
+
+		if ((strncmp(match, e, matchlen) == 0)
+		 && ((e[matchlen] == '\0')
+		   || (e[matchlen] == '='))) {
+			char *cp = strchr(e, '=');
+			return cp ? ++cp : "";
+		}
+	}
+	return NULL;
+}
+
+/*
+ * kdballocenv - This function is used to allocate bytes for
+ *	environment entries.
+ * Parameters:
+ *	match	A character string representing a numeric value
+ * Outputs:
+ *	*value  the unsigned long representation of the env variable 'match'
+ * Returns:
+ *	Zero on success, a kdb diagnostic on failure.
+ * Remarks:
+ *	We use a static environment buffer (envbuffer) to hold the values
+ *	of dynamically generated environment variables (see kdb_set).  Buffer
+ *	space once allocated is never free'd, so over time, the amount of space
+ *	(currently 512 bytes) will be exhausted if env variables are changed
+ *	frequently.
+ */
+static char *kdballocenv(size_t bytes)
+{
+#define	KDB_ENVBUFSIZE	512
+	static char envbuffer[KDB_ENVBUFSIZE];
+	static int envbufsize;
+	char *ep = NULL;
+
+	if ((KDB_ENVBUFSIZE - envbufsize) >= bytes) {
+		ep = &envbuffer[envbufsize];
+		envbufsize += bytes;
+	}
+	return ep;
+}
+
+/*
+ * kdbgetulenv - This function will return the value of an unsigned
+ *	long-valued environment variable.
+ * Parameters:
+ *	match	A character string representing a numeric value
+ * Outputs:
+ *	*value  the unsigned long representation of the env variable 'match'
+ * Returns:
+ *	Zero on success, a kdb diagnostic on failure.
+ */
+static int kdbgetulenv(const char *match, unsigned long *value)
+{
+	char *ep;
+
+	ep = kdbgetenv(match);
+	if (!ep)
+		return KDB_NOTENV;
+	if (strlen(ep) == 0)
+		return KDB_NOENVVALUE;
+
+	*value = simple_strtoul(ep, NULL, 0);
+
+	return 0;
+}
+
+/*
+ * kdbgetintenv - This function will return the value of an
+ *	integer-valued environment variable.
+ * Parameters:
+ *	match	A character string representing an integer-valued env variable
+ * Outputs:
+ *	*value  the integer representation of the environment variable 'match'
+ * Returns:
+ *	Zero on success, a kdb diagnostic on failure.
+ */
+int kdbgetintenv(const char *match, int *value)
+{
+	unsigned long val;
+	int diag;
+
+	diag = kdbgetulenv(match, &val);
+	if (!diag)
+		*value = (int) val;
+	return diag;
+}
+
+/*
+ * kdb_setenv() - Alter an existing environment variable or create a new one.
+ * @var: Name of the variable
+ * @val: Value of the variable
+ *
+ * Return: Zero on success, a kdb diagnostic on failure.
+ */
+static int kdb_setenv(const char *var, const char *val)
+{
+	int i;
+	char *ep;
+	size_t varlen, vallen;
+
+	varlen = strlen(var);
+	vallen = strlen(val);
+	ep = kdballocenv(varlen + vallen + 2);
+	if (ep == (char *)0)
+		return KDB_ENVBUFFULL;
+
+	sprintf(ep, "%s=%s", var, val);
+
+	for (i = 0; i < __nenv; i++) {
+		if (__env[i]
+		 && ((strncmp(__env[i], var, varlen) == 0)
+		   && ((__env[i][varlen] == '\0')
+		    || (__env[i][varlen] == '=')))) {
+			__env[i] = ep;
+			return 0;
+		}
+	}
+
+	/*
+	 * Wasn't existing variable.  Fit into slot.
+	 */
+	for (i = 0; i < __nenv-1; i++) {
+		if (__env[i] == (char *)0) {
+			__env[i] = ep;
+			return 0;
+		}
+	}
+
+	return KDB_ENVFULL;
+}
+
+/*
+ * kdb_printenv() - Display the current environment variables.
+ */
+static void kdb_printenv(void)
+{
+	int i;
+
+	for (i = 0; i < __nenv; i++) {
+		if (__env[i])
+			kdb_printf("%s\n", __env[i]);
+	}
+}
+
+/*
+ * kdbgetularg - This function will convert a numeric string into an
+ *	unsigned long value.
+ * Parameters:
+ *	arg	A character string representing a numeric value
+ * Outputs:
+ *	*value  the unsigned long representation of arg.
+ * Returns:
+ *	Zero on success, a kdb diagnostic on failure.
+ */
+int kdbgetularg(const char *arg, unsigned long *value)
+{
+	char *endp;
+	unsigned long val;
+
+	val = simple_strtoul(arg, &endp, 0);
+
+	if (endp == arg) {
+		/*
+		 * Also try base 16, for us folks too lazy to type the
+		 * leading 0x...
+		 */
+		val = simple_strtoul(arg, &endp, 16);
+		if (endp == arg)
+			return KDB_BADINT;
+	}
+
+	*value = val;
+
+	return 0;
+}
+
+int kdbgetu64arg(const char *arg, u64 *value)
+{
+	char *endp;
+	u64 val;
+
+	val = simple_strtoull(arg, &endp, 0);
+
+	if (endp == arg) {
+
+		val = simple_strtoull(arg, &endp, 16);
+		if (endp == arg)
+			return KDB_BADINT;
+	}
+
+	*value = val;
+
+	return 0;
+}
+
+/*
+ * kdb_set - This function implements the 'set' command.  Alter an
+ *	existing environment variable or create a new one.
+ */
+int kdb_set(int argc, const char **argv)
+{
+	/*
+	 * we can be invoked two ways:
+	 *   set var=value    argv[1]="var", argv[2]="value"
+	 *   set var = value  argv[1]="var", argv[2]="=", argv[3]="value"
+	 * - if the latter, shift 'em down.
+	 */
+	if (argc == 3) {
+		argv[2] = argv[3];
+		argc--;
+	}
+
+	if (argc != 2)
+		return KDB_ARGCOUNT;
+
+	/*
+	 * Censor sensitive variables
+	 */
+	if (strcmp(argv[1], "PROMPT") == 0 &&
+	    !kdb_check_flags(KDB_ENABLE_MEM_READ, kdb_cmd_enabled, false))
+		return KDB_NOPERM;
+
+	/*
+	 * Check for internal variables
+	 */
+	if (strcmp(argv[1], "KDBDEBUG") == 0) {
+		unsigned int debugflags;
+		char *cp;
+
+		debugflags = simple_strtoul(argv[2], &cp, 0);
+		if (cp == argv[2] || debugflags & ~KDB_DEBUG_FLAG_MASK) {
+			kdb_printf("kdb: illegal debug flags '%s'\n",
+				    argv[2]);
+			return 0;
+		}
+		kdb_flags = (kdb_flags & ~KDB_DEBUG(MASK))
+			| (debugflags << KDB_DEBUG_FLAG_SHIFT);
+
+		return 0;
+	}
+
+	/*
+	 * Tokenizer squashed the '=' sign.  argv[1] is variable
+	 * name, argv[2] = value.
+	 */
+	return kdb_setenv(argv[1], argv[2]);
+}
+
+static int kdb_check_regs(void)
+{
+	if (!kdb_current_regs) {
+		kdb_printf("No current kdb registers."
+			   "  You may need to select another task\n");
+		return KDB_BADREG;
+	}
+	return 0;
+}
+
+/*
+ * kdbgetaddrarg - This function is responsible for parsing an
+ *	address-expression and returning the value of the expression,
+ *	symbol name, and offset to the caller.
+ *
+ *	The argument may consist of a numeric value (decimal or
+ *	hexadecimal), a symbol name, a register name (preceded by the
+ *	percent sign), an environment variable with a numeric value
+ *	(preceded by a dollar sign) or a simple arithmetic expression
+ *	consisting of a symbol name, +/-, and a numeric constant value
+ *	(offset).
+ * Parameters:
+ *	argc	- count of arguments in argv
+ *	argv	- argument vector
+ *	*nextarg - index to next unparsed argument in argv[]
+ *	regs	- Register state at time of KDB entry
+ * Outputs:
+ *	*value	- receives the value of the address-expression
+ *	*offset - receives the offset specified, if any
+ *	*name   - receives the symbol name, if any
+ *	*nextarg - index to next unparsed argument in argv[]
+ * Returns:
+ *	zero is returned on success, a kdb diagnostic code is
+ *      returned on error.
+ */
+int kdbgetaddrarg(int argc, const char **argv, int *nextarg,
+		  unsigned long *value,  long *offset,
+		  char **name)
+{
+	unsigned long addr;
+	unsigned long off = 0;
+	int positive;
+	int diag;
+	int found = 0;
+	char *symname;
+	char symbol = '\0';
+	char *cp;
+	kdb_symtab_t symtab;
+
+	/*
+	 * If the enable flags prohibit both arbitrary memory access
+	 * and flow control then there are no reasonable grounds to
+	 * provide symbol lookup.
+	 */
+	if (!kdb_check_flags(KDB_ENABLE_MEM_READ | KDB_ENABLE_FLOW_CTRL,
+			     kdb_cmd_enabled, false))
+		return KDB_NOPERM;
+
+	/*
+	 * Process arguments which follow the following syntax:
+	 *
+	 *  symbol | numeric-address [+/- numeric-offset]
+	 *  %register
+	 *  $environment-variable
+	 */
+
+	if (*nextarg > argc)
+		return KDB_ARGCOUNT;
+
+	symname = (char *)argv[*nextarg];
+
+	/*
+	 * If there is no whitespace between the symbol
+	 * or address and the '+' or '-' symbols, we
+	 * remember the character and replace it with a
+	 * null so the symbol/value can be properly parsed
+	 */
+	cp = strpbrk(symname, "+-");
+	if (cp != NULL) {
+		symbol = *cp;
+		*cp++ = '\0';
+	}
+
+	if (symname[0] == '$') {
+		diag = kdbgetulenv(&symname[1], &addr);
+		if (diag)
+			return diag;
+	} else if (symname[0] == '%') {
+		diag = kdb_check_regs();
+		if (diag)
+			return diag;
+		/* Implement register values with % at a later time as it is
+		 * arch optional.
+		 */
+		return KDB_NOTIMP;
+	} else {
+		found = kdbgetsymval(symname, &symtab);
+		if (found) {
+			addr = symtab.sym_start;
+		} else {
+			diag = kdbgetularg(argv[*nextarg], &addr);
+			if (diag)
+				return diag;
+		}
+	}
+
+	if (!found)
+		found = kdbnearsym(addr, &symtab);
+
+	(*nextarg)++;
+
+	if (name)
+		*name = symname;
+	if (value)
+		*value = addr;
+	if (offset && name && *name)
+		*offset = addr - symtab.sym_start;
+
+	if ((*nextarg > argc)
+	 && (symbol == '\0'))
+		return 0;
+
+	/*
+	 * check for +/- and offset
+	 */
+
+	if (symbol == '\0') {
+		if ((argv[*nextarg][0] != '+')
+		 && (argv[*nextarg][0] != '-')) {
+			/*
+			 * Not our argument.  Return.
+			 */
+			return 0;
+		} else {
+			positive = (argv[*nextarg][0] == '+');
+			(*nextarg)++;
+		}
+	} else
+		positive = (symbol == '+');
+
+	/*
+	 * Now there must be an offset!
+	 */
+	if ((*nextarg > argc)
+	 && (symbol == '\0')) {
+		return KDB_INVADDRFMT;
+	}
+
+	if (!symbol) {
+		cp = (char *)argv[*nextarg];
+		(*nextarg)++;
+	}
+
+	diag = kdbgetularg(cp, &off);
+	if (diag)
+		return diag;
+
+	if (!positive)
+		off = -off;
+
+	if (offset)
+		*offset += off;
+
+	if (value)
+		*value += off;
+
+	return 0;
+}
+
+static void kdb_cmderror(int diag)
+{
+	int i;
+
+	if (diag >= 0) {
+		kdb_printf("no error detected (diagnostic is %d)\n", diag);
+		return;
+	}
+
+	for (i = 0; i < __nkdb_err; i++) {
+		if (kdbmsgs[i].km_diag == diag) {
+			kdb_printf("diag: %d: %s\n", diag, kdbmsgs[i].km_msg);
+			return;
+		}
+	}
+
+	kdb_printf("Unknown diag %d\n", -diag);
+}
+
+/*
+ * kdb_defcmd, kdb_defcmd2 - This function implements the 'defcmd'
+ *	command which defines one command as a set of other commands,
+ *	terminated by endefcmd.  kdb_defcmd processes the initial
+ *	'defcmd' command, kdb_defcmd2 is invoked from kdb_parse for
+ *	the following commands until 'endefcmd'.
+ * Inputs:
+ *	argc	argument count
+ *	argv	argument vector
+ * Returns:
+ *	zero for success, a kdb diagnostic if error
+ */
+struct kdb_macro {
+	kdbtab_t cmd;			/* Macro command */
+	struct list_head statements;	/* Associated statement list */
+};
+
+struct kdb_macro_statement {
+	char *statement;		/* Statement text */
+	struct list_head list_node;	/* Statement list node */
+};
+
+static struct kdb_macro *kdb_macro;
+static bool defcmd_in_progress;
+
+/* Forward references */
+static int kdb_exec_defcmd(int argc, const char **argv);
+
+static int kdb_defcmd2(const char *cmdstr, const char *argv0)
+{
+	struct kdb_macro_statement *kms;
+
+	if (!kdb_macro)
+		return KDB_NOTIMP;
+
+	if (strcmp(argv0, "endefcmd") == 0) {
+		defcmd_in_progress = false;
+		if (!list_empty(&kdb_macro->statements))
+			kdb_register(&kdb_macro->cmd);
+		return 0;
+	}
+
+	kms = kmalloc(sizeof(*kms), GFP_KDB);
+	if (!kms) {
+		kdb_printf("Could not allocate new kdb macro command: %s\n",
+			   cmdstr);
+		return KDB_NOTIMP;
+	}
+
+	kms->statement = kdb_strdup(cmdstr, GFP_KDB);
+	list_add_tail(&kms->list_node, &kdb_macro->statements);
+
+	return 0;
+}
+
+static int kdb_defcmd(int argc, const char **argv)
+{
+	kdbtab_t *mp;
+
+	if (defcmd_in_progress) {
+		kdb_printf("kdb: nested defcmd detected, assuming missing "
+			   "endefcmd\n");
+		kdb_defcmd2("endefcmd", "endefcmd");
+	}
+	if (argc == 0) {
+		kdbtab_t *kp;
+		struct kdb_macro *kmp;
+		struct kdb_macro_statement *kms;
+
+		list_for_each_entry(kp, &kdb_cmds_head, list_node) {
+			if (kp->func == kdb_exec_defcmd) {
+				kdb_printf("defcmd %s \"%s\" \"%s\"\n",
+					   kp->name, kp->usage, kp->help);
+				kmp = container_of(kp, struct kdb_macro, cmd);
+				list_for_each_entry(kms, &kmp->statements,
+						    list_node)
+					kdb_printf("%s", kms->statement);
+				kdb_printf("endefcmd\n");
+			}
+		}
+		return 0;
+	}
+	if (argc != 3)
+		return KDB_ARGCOUNT;
+	if (in_dbg_master()) {
+		kdb_printf("Command only available during kdb_init()\n");
+		return KDB_NOTIMP;
+	}
+	kdb_macro = kzalloc(sizeof(*kdb_macro), GFP_KDB);
+	if (!kdb_macro)
+		goto fail_defcmd;
+
+	mp = &kdb_macro->cmd;
+	mp->func = kdb_exec_defcmd;
+	mp->minlen = 0;
+	mp->flags = KDB_ENABLE_ALWAYS_SAFE;
+	mp->name = kdb_strdup(argv[1], GFP_KDB);
+	if (!mp->name)
+		goto fail_name;
+	mp->usage = kdb_strdup(argv[2], GFP_KDB);
+	if (!mp->usage)
+		goto fail_usage;
+	mp->help = kdb_strdup(argv[3], GFP_KDB);
+	if (!mp->help)
+		goto fail_help;
+	if (mp->usage[0] == '"') {
+		strcpy(mp->usage, argv[2]+1);
+		mp->usage[strlen(mp->usage)-1] = '\0';
+	}
+	if (mp->help[0] == '"') {
+		strcpy(mp->help, argv[3]+1);
+		mp->help[strlen(mp->help)-1] = '\0';
+	}
+
+	INIT_LIST_HEAD(&kdb_macro->statements);
+	defcmd_in_progress = true;
+	return 0;
+fail_help:
+	kfree(mp->usage);
+fail_usage:
+	kfree(mp->name);
+fail_name:
+	kfree(kdb_macro);
+fail_defcmd:
+	kdb_printf("Could not allocate new kdb_macro entry for %s\n", argv[1]);
+	return KDB_NOTIMP;
+}
+
+/*
+ * kdb_exec_defcmd - Execute the set of commands associated with this
+ *	defcmd name.
+ * Inputs:
+ *	argc	argument count
+ *	argv	argument vector
+ * Returns:
+ *	zero for success, a kdb diagnostic if error
+ */
+static int kdb_exec_defcmd(int argc, const char **argv)
+{
+	int ret;
+	kdbtab_t *kp;
+	struct kdb_macro *kmp;
+	struct kdb_macro_statement *kms;
+
+	if (argc != 0)
+		return KDB_ARGCOUNT;
+
+	list_for_each_entry(kp, &kdb_cmds_head, list_node) {
+		if (strcmp(kp->name, argv[0]) == 0)
+			break;
+	}
+	if (list_entry_is_head(kp, &kdb_cmds_head, list_node)) {
+		kdb_printf("kdb_exec_defcmd: could not find commands for %s\n",
+			   argv[0]);
+		return KDB_NOTIMP;
+	}
+	kmp = container_of(kp, struct kdb_macro, cmd);
+	list_for_each_entry(kms, &kmp->statements, list_node) {
+		/*
+		 * Recursive use of kdb_parse, do not use argv after this point.
+		 */
+		argv = NULL;
+		kdb_printf("[%s]kdb> %s\n", kmp->cmd.name, kms->statement);
+		ret = kdb_parse(kms->statement);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+/* Command history */
+#define KDB_CMD_HISTORY_COUNT	32
+#define CMD_BUFLEN		200	/* kdb_printf: max printline
+					 * size == 256 */
+static unsigned int cmd_head, cmd_tail;
+static unsigned int cmdptr;
+static char cmd_hist[KDB_CMD_HISTORY_COUNT][CMD_BUFLEN];
+static char cmd_cur[CMD_BUFLEN];
+
+/*
+ * The "str" argument may point to something like  | grep xyz
+ */
+static void parse_grep(const char *str)
+{
+	int	len;
+	char	*cp = (char *)str, *cp2;
+
+	/* sanity check: we should have been called with the \ first */
+	if (*cp != '|')
+		return;
+	cp++;
+	while (isspace(*cp))
+		cp++;
+	if (!str_has_prefix(cp, "grep ")) {
+		kdb_printf("invalid 'pipe', see grephelp\n");
+		return;
+	}
+	cp += 5;
+	while (isspace(*cp))
+		cp++;
+	cp2 = strchr(cp, '\n');
+	if (cp2)
+		*cp2 = '\0'; /* remove the trailing newline */
+	len = strlen(cp);
+	if (len == 0) {
+		kdb_printf("invalid 'pipe', see grephelp\n");
+		return;
+	}
+	/* now cp points to a nonzero length search string */
+	if (*cp == '"') {
+		/* allow it be "x y z" by removing the "'s - there must
+		   be two of them */
+		cp++;
+		cp2 = strchr(cp, '"');
+		if (!cp2) {
+			kdb_printf("invalid quoted string, see grephelp\n");
+			return;
+		}
+		*cp2 = '\0'; /* end the string where the 2nd " was */
+	}
+	kdb_grep_leading = 0;
+	if (*cp == '^') {
+		kdb_grep_leading = 1;
+		cp++;
+	}
+	len = strlen(cp);
+	kdb_grep_trailing = 0;
+	if (*(cp+len-1) == '$') {
+		kdb_grep_trailing = 1;
+		*(cp+len-1) = '\0';
+	}
+	len = strlen(cp);
+	if (!len)
+		return;
+	if (len >= KDB_GREP_STRLEN) {
+		kdb_printf("search string too long\n");
+		return;
+	}
+	strcpy(kdb_grep_string, cp);
+	kdb_grepping_flag++;
+	return;
+}
+
+/*
+ * kdb_parse - Parse the command line, search the command table for a
+ *	matching command and invoke the command function.  This
+ *	function may be called recursively, if it is, the second call
+ *	will overwrite argv and cbuf.  It is the caller's
+ *	responsibility to save their argv if they recursively call
+ *	kdb_parse().
+ * Parameters:
+ *      cmdstr	The input command line to be parsed.
+ *	regs	The registers at the time kdb was entered.
+ * Returns:
+ *	Zero for success, a kdb diagnostic if failure.
+ * Remarks:
+ *	Limited to 20 tokens.
+ *
+ *	Real rudimentary tokenization. Basically only whitespace
+ *	is considered a token delimiter (but special consideration
+ *	is taken of the '=' sign as used by the 'set' command).
+ *
+ *	The algorithm used to tokenize the input string relies on
+ *	there being at least one whitespace (or otherwise useless)
+ *	character between tokens as the character immediately following
+ *	the token is altered in-place to a null-byte to terminate the
+ *	token string.
+ */
+
+#define MAXARGC	20
+
+int kdb_parse(const char *cmdstr)
+{
+	static char *argv[MAXARGC];
+	static int argc;
+	static char cbuf[CMD_BUFLEN+2];
+	char *cp;
+	char *cpp, quoted;
+	kdbtab_t *tp;
+	int escaped, ignore_errors = 0, check_grep = 0;
+
+	/*
+	 * First tokenize the command string.
+	 */
+	cp = (char *)cmdstr;
+
+	if (KDB_FLAG(CMD_INTERRUPT)) {
+		/* Previous command was interrupted, newline must not
+		 * repeat the command */
+		KDB_FLAG_CLEAR(CMD_INTERRUPT);
+		KDB_STATE_SET(PAGER);
+		argc = 0;	/* no repeat */
+	}
+
+	if (*cp != '\n' && *cp != '\0') {
+		argc = 0;
+		cpp = cbuf;
+		while (*cp) {
+			/* skip whitespace */
+			while (isspace(*cp))
+				cp++;
+			if ((*cp == '\0') || (*cp == '\n') ||
+			    (*cp == '#' && !defcmd_in_progress))
+				break;
+			/* special case: check for | grep pattern */
+			if (*cp == '|') {
+				check_grep++;
+				break;
+			}
+			if (cpp >= cbuf + CMD_BUFLEN) {
+				kdb_printf("kdb_parse: command buffer "
+					   "overflow, command ignored\n%s\n",
+					   cmdstr);
+				return KDB_NOTFOUND;
+			}
+			if (argc >= MAXARGC - 1) {
+				kdb_printf("kdb_parse: too many arguments, "
+					   "command ignored\n%s\n", cmdstr);
+				return KDB_NOTFOUND;
+			}
+			argv[argc++] = cpp;
+			escaped = 0;
+			quoted = '\0';
+			/* Copy to next unquoted and unescaped
+			 * whitespace or '=' */
+			while (*cp && *cp != '\n' &&
+			       (escaped || quoted || !isspace(*cp))) {
+				if (cpp >= cbuf + CMD_BUFLEN)
+					break;
+				if (escaped) {
+					escaped = 0;
+					*cpp++ = *cp++;
+					continue;
+				}
+				if (*cp == '\\') {
+					escaped = 1;
+					++cp;
+					continue;
+				}
+				if (*cp == quoted)
+					quoted = '\0';
+				else if (*cp == '\'' || *cp == '"')
+					quoted = *cp;
+				*cpp = *cp++;
+				if (*cpp == '=' && !quoted)
+					break;
+				++cpp;
+			}
+			*cpp++ = '\0';	/* Squash a ws or '=' character */
+		}
+	}
+	if (!argc)
+		return 0;
+	if (check_grep)
+		parse_grep(cp);
+	if (defcmd_in_progress) {
+		int result = kdb_defcmd2(cmdstr, argv[0]);
+		if (!defcmd_in_progress) {
+			argc = 0;	/* avoid repeat on endefcmd */
+			*(argv[0]) = '\0';
+		}
+		return result;
+	}
+	if (argv[0][0] == '-' && argv[0][1] &&
+	    (argv[0][1] < '0' || argv[0][1] > '9')) {
+		ignore_errors = 1;
+		++argv[0];
+	}
+
+	list_for_each_entry(tp, &kdb_cmds_head, list_node) {
+		/*
+		 * If this command is allowed to be abbreviated,
+		 * check to see if this is it.
+		 */
+		if (tp->minlen && (strlen(argv[0]) <= tp->minlen) &&
+		    (strncmp(argv[0], tp->name, tp->minlen) == 0))
+			break;
+
+		if (strcmp(argv[0], tp->name) == 0)
+			break;
+	}
+
+	/*
+	 * If we don't find a command by this name, see if the first
+	 * few characters of this match any of the known commands.
+	 * e.g., md1c20 should match md.
+	 */
+	if (list_entry_is_head(tp, &kdb_cmds_head, list_node)) {
+		list_for_each_entry(tp, &kdb_cmds_head, list_node) {
+			if (strncmp(argv[0], tp->name, strlen(tp->name)) == 0)
+				break;
+		}
+	}
+
+	if (!list_entry_is_head(tp, &kdb_cmds_head, list_node)) {
+		int result;
+
+		if (!kdb_check_flags(tp->flags, kdb_cmd_enabled, argc <= 1))
+			return KDB_NOPERM;
+
+		KDB_STATE_SET(CMD);
+		result = (*tp->func)(argc-1, (const char **)argv);
+		if (result && ignore_errors && result > KDB_CMD_GO)
+			result = 0;
+		KDB_STATE_CLEAR(CMD);
+
+		if (tp->flags & KDB_REPEAT_WITH_ARGS)
+			return result;
+
+		argc = tp->flags & KDB_REPEAT_NO_ARGS ? 1 : 0;
+		if (argv[argc])
+			*(argv[argc]) = '\0';
+		return result;
+	}
+
+	/*
+	 * If the input with which we were presented does not
+	 * map to an existing command, attempt to parse it as an
+	 * address argument and display the result.   Useful for
+	 * obtaining the address of a variable, or the nearest symbol
+	 * to an address contained in a register.
+	 */
+	{
+		unsigned long value;
+		char *name = NULL;
+		long offset;
+		int nextarg = 0;
+
+		if (kdbgetaddrarg(0, (const char **)argv, &nextarg,
+				  &value, &offset, &name)) {
+			return KDB_NOTFOUND;
+		}
+
+		kdb_printf("%s = ", argv[0]);
+		kdb_symbol_print(value, NULL, KDB_SP_DEFAULT);
+		kdb_printf("\n");
+		return 0;
+	}
+}
+
+
+static int handle_ctrl_cmd(char *cmd)
+{
+#define CTRL_P	16
+#define CTRL_N	14
+
+	/* initial situation */
+	if (cmd_head == cmd_tail)
+		return 0;
+	switch (*cmd) {
+	case CTRL_P:
+		if (cmdptr != cmd_tail)
+			cmdptr = (cmdptr + KDB_CMD_HISTORY_COUNT - 1) %
+				 KDB_CMD_HISTORY_COUNT;
+		strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
+		return 1;
+	case CTRL_N:
+		if (cmdptr != cmd_head)
+			cmdptr = (cmdptr+1) % KDB_CMD_HISTORY_COUNT;
+		strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * kdb_reboot - This function implements the 'reboot' command.  Reboot
+ *	the system immediately, or loop for ever on failure.
+ */
+static int kdb_reboot(int argc, const char **argv)
+{
+	emergency_restart();
+	kdb_printf("Hmm, kdb_reboot did not reboot, spinning here\n");
+	while (1)
+		cpu_relax();
+	/* NOTREACHED */
+	return 0;
+}
+
+static void kdb_dumpregs(struct pt_regs *regs)
+{
+	int old_lvl = console_loglevel;
+	console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
+	kdb_trap_printk++;
+	show_regs(regs);
+	kdb_trap_printk--;
+	kdb_printf("\n");
+	console_loglevel = old_lvl;
+}
+
+static void kdb_set_current_task(struct task_struct *p)
+{
+	kdb_current_task = p;
+
+	if (kdb_task_has_cpu(p)) {
+		kdb_current_regs = KDB_TSKREGS(kdb_process_cpu(p));
+		return;
+	}
+	kdb_current_regs = NULL;
+}
+
+static void drop_newline(char *buf)
+{
+	size_t len = strlen(buf);
+
+	if (len == 0)
+		return;
+	if (*(buf + len - 1) == '\n')
+		*(buf + len - 1) = '\0';
+}
+
+/*
+ * kdb_local - The main code for kdb.  This routine is invoked on a
+ *	specific processor, it is not global.  The main kdb() routine
+ *	ensures that only one processor at a time is in this routine.
+ *	This code is called with the real reason code on the first
+ *	entry to a kdb session, thereafter it is called with reason
+ *	SWITCH, even if the user goes back to the original cpu.
+ * Inputs:
+ *	reason		The reason KDB was invoked
+ *	error		The hardware-defined error code
+ *	regs		The exception frame at time of fault/breakpoint.
+ *	db_result	Result code from the break or debug point.
+ * Returns:
+ *	0	KDB was invoked for an event which it wasn't responsible
+ *	1	KDB handled the event for which it was invoked.
+ *	KDB_CMD_GO	User typed 'go'.
+ *	KDB_CMD_CPU	User switched to another cpu.
+ *	KDB_CMD_SS	Single step.
+ */
+static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
+		     kdb_dbtrap_t db_result)
+{
+	char *cmdbuf;
+	int diag;
+	struct task_struct *kdb_current =
+		kdb_curr_task(raw_smp_processor_id());
+
+	KDB_DEBUG_STATE("kdb_local 1", reason);
+
+	kdb_check_for_lockdown();
+
+	kdb_go_count = 0;
+	if (reason == KDB_REASON_DEBUG) {
+		/* special case below */
+	} else {
+		kdb_printf("\nEntering kdb (current=0x%px, pid %d) ",
+			   kdb_current, kdb_current ? kdb_current->pid : 0);
+#if defined(CONFIG_SMP)
+		kdb_printf("on processor %d ", raw_smp_processor_id());
+#endif
+	}
+
+	switch (reason) {
+	case KDB_REASON_DEBUG:
+	{
+		/*
+		 * If re-entering kdb after a single step
+		 * command, don't print the message.
+		 */
+		switch (db_result) {
+		case KDB_DB_BPT:
+			kdb_printf("\nEntering kdb (0x%px, pid %d) ",
+				   kdb_current, kdb_current->pid);
+#if defined(CONFIG_SMP)
+			kdb_printf("on processor %d ", raw_smp_processor_id());
+#endif
+			kdb_printf("due to Debug @ " kdb_machreg_fmt "\n",
+				   instruction_pointer(regs));
+			break;
+		case KDB_DB_SS:
+			break;
+		case KDB_DB_SSBPT:
+			KDB_DEBUG_STATE("kdb_local 4", reason);
+			return 1;	/* kdba_db_trap did the work */
+		default:
+			kdb_printf("kdb: Bad result from kdba_db_trap: %d\n",
+				   db_result);
+			break;
+		}
+
+	}
+		break;
+	case KDB_REASON_ENTER:
+		if (KDB_STATE(KEYBOARD))
+			kdb_printf("due to Keyboard Entry\n");
+		else
+			kdb_printf("due to KDB_ENTER()\n");
+		break;
+	case KDB_REASON_KEYBOARD:
+		KDB_STATE_SET(KEYBOARD);
+		kdb_printf("due to Keyboard Entry\n");
+		break;
+	case KDB_REASON_ENTER_SLAVE:
+		/* drop through, slaves only get released via cpu switch */
+	case KDB_REASON_SWITCH:
+		kdb_printf("due to cpu switch\n");
+		break;
+	case KDB_REASON_OOPS:
+		kdb_printf("Oops: %s\n", kdb_diemsg);
+		kdb_printf("due to oops @ " kdb_machreg_fmt "\n",
+			   instruction_pointer(regs));
+		kdb_dumpregs(regs);
+		break;
+	case KDB_REASON_SYSTEM_NMI:
+		kdb_printf("due to System NonMaskable Interrupt\n");
+		break;
+	case KDB_REASON_NMI:
+		kdb_printf("due to NonMaskable Interrupt @ "
+			   kdb_machreg_fmt "\n",
+			   instruction_pointer(regs));
+		break;
+	case KDB_REASON_SSTEP:
+	case KDB_REASON_BREAK:
+		kdb_printf("due to %s @ " kdb_machreg_fmt "\n",
+			   reason == KDB_REASON_BREAK ?
+			   "Breakpoint" : "SS trap", instruction_pointer(regs));
+		/*
+		 * Determine if this breakpoint is one that we
+		 * are interested in.
+		 */
+		if (db_result != KDB_DB_BPT) {
+			kdb_printf("kdb: error return from kdba_bp_trap: %d\n",
+				   db_result);
+			KDB_DEBUG_STATE("kdb_local 6", reason);
+			return 0;	/* Not for us, dismiss it */
+		}
+		break;
+	case KDB_REASON_RECURSE:
+		kdb_printf("due to Recursion @ " kdb_machreg_fmt "\n",
+			   instruction_pointer(regs));
+		break;
+	default:
+		kdb_printf("kdb: unexpected reason code: %d\n", reason);
+		KDB_DEBUG_STATE("kdb_local 8", reason);
+		return 0;	/* Not for us, dismiss it */
+	}
+
+	while (1) {
+		/*
+		 * Initialize pager context.
+		 */
+		kdb_nextline = 1;
+		KDB_STATE_CLEAR(SUPPRESS);
+		kdb_grepping_flag = 0;
+		/* ensure the old search does not leak into '/' commands */
+		kdb_grep_string[0] = '\0';
+
+		cmdbuf = cmd_cur;
+		*cmdbuf = '\0';
+		*(cmd_hist[cmd_head]) = '\0';
+
+do_full_getstr:
+		/* PROMPT can only be set if we have MEM_READ permission. */
+		snprintf(kdb_prompt_str, CMD_BUFLEN, kdbgetenv("PROMPT"),
+			 raw_smp_processor_id());
+
+		/*
+		 * Fetch command from keyboard
+		 */
+		cmdbuf = kdb_getstr(cmdbuf, CMD_BUFLEN, kdb_prompt_str);
+		if (*cmdbuf != '\n') {
+			if (*cmdbuf < 32) {
+				if (cmdptr == cmd_head) {
+					strscpy(cmd_hist[cmd_head], cmd_cur,
+						CMD_BUFLEN);
+					*(cmd_hist[cmd_head] +
+					  strlen(cmd_hist[cmd_head])-1) = '\0';
+				}
+				if (!handle_ctrl_cmd(cmdbuf))
+					*(cmd_cur+strlen(cmd_cur)-1) = '\0';
+				cmdbuf = cmd_cur;
+				goto do_full_getstr;
+			} else {
+				strscpy(cmd_hist[cmd_head], cmd_cur,
+					CMD_BUFLEN);
+			}
+
+			cmd_head = (cmd_head+1) % KDB_CMD_HISTORY_COUNT;
+			if (cmd_head == cmd_tail)
+				cmd_tail = (cmd_tail+1) % KDB_CMD_HISTORY_COUNT;
+		}
+
+		cmdptr = cmd_head;
+		diag = kdb_parse(cmdbuf);
+		if (diag == KDB_NOTFOUND) {
+			drop_newline(cmdbuf);
+			kdb_printf("Unknown kdb command: '%s'\n", cmdbuf);
+			diag = 0;
+		}
+		if (diag == KDB_CMD_GO
+		 || diag == KDB_CMD_CPU
+		 || diag == KDB_CMD_SS
+		 || diag == KDB_CMD_KGDB)
+			break;
+
+		if (diag)
+			kdb_cmderror(diag);
+	}
+	KDB_DEBUG_STATE("kdb_local 9", diag);
+	return diag;
+}
+
+
+/*
+ * kdb_print_state - Print the state data for the current processor
+ *	for debugging.
+ * Inputs:
+ *	text		Identifies the debug point
+ *	value		Any integer value to be printed, e.g. reason code.
+ */
+void kdb_print_state(const char *text, int value)
+{
+	kdb_printf("state: %s cpu %d value %d initial %d state %x\n",
+		   text, raw_smp_processor_id(), value, kdb_initial_cpu,
+		   kdb_state);
+}
+
+/*
+ * kdb_main_loop - After initial setup and assignment of the
+ *	controlling cpu, all cpus are in this loop.  One cpu is in
+ *	control and will issue the kdb prompt, the others will spin
+ *	until 'go' or cpu switch.
+ *
+ *	To get a consistent view of the kernel stacks for all
+ *	processes, this routine is invoked from the main kdb code via
+ *	an architecture specific routine.  kdba_main_loop is
+ *	responsible for making the kernel stacks consistent for all
+ *	processes, there should be no difference between a blocked
+ *	process and a running process as far as kdb is concerned.
+ * Inputs:
+ *	reason		The reason KDB was invoked
+ *	error		The hardware-defined error code
+ *	reason2		kdb's current reason code.
+ *			Initially error but can change
+ *			according to kdb state.
+ *	db_result	Result code from break or debug point.
+ *	regs		The exception frame at time of fault/breakpoint.
+ *			should always be valid.
+ * Returns:
+ *	0	KDB was invoked for an event which it wasn't responsible
+ *	1	KDB handled the event for which it was invoked.
+ */
+int kdb_main_loop(kdb_reason_t reason, kdb_reason_t reason2, int error,
+	      kdb_dbtrap_t db_result, struct pt_regs *regs)
+{
+	int result = 1;
+	/* Stay in kdb() until 'go', 'ss[b]' or an error */
+	while (1) {
+		/*
+		 * All processors except the one that is in control
+		 * will spin here.
+		 */
+		KDB_DEBUG_STATE("kdb_main_loop 1", reason);
+		while (KDB_STATE(HOLD_CPU)) {
+			/* state KDB is turned off by kdb_cpu to see if the
+			 * other cpus are still live, each cpu in this loop
+			 * turns it back on.
+			 */
+			if (!KDB_STATE(KDB))
+				KDB_STATE_SET(KDB);
+		}
+
+		KDB_STATE_CLEAR(SUPPRESS);
+		KDB_DEBUG_STATE("kdb_main_loop 2", reason);
+		if (KDB_STATE(LEAVING))
+			break;	/* Another cpu said 'go' */
+		/* Still using kdb, this processor is in control */
+		result = kdb_local(reason2, error, regs, db_result);
+		KDB_DEBUG_STATE("kdb_main_loop 3", result);
+
+		if (result == KDB_CMD_CPU)
+			break;
+
+		if (result == KDB_CMD_SS) {
+			KDB_STATE_SET(DOING_SS);
+			break;
+		}
+
+		if (result == KDB_CMD_KGDB) {
+			if (!KDB_STATE(DOING_KGDB))
+				kdb_printf("Entering please attach debugger "
+					   "or use $D#44+ or $3#33\n");
+			break;
+		}
+		if (result && result != 1 && result != KDB_CMD_GO)
+			kdb_printf("\nUnexpected kdb_local return code %d\n",
+				   result);
+		KDB_DEBUG_STATE("kdb_main_loop 4", reason);
+		break;
+	}
+	if (KDB_STATE(DOING_SS))
+		KDB_STATE_CLEAR(SSBPT);
+
+	/* Clean up any keyboard devices before leaving */
+	kdb_kbd_cleanup_state();
+
+	return result;
+}
+
+/*
+ * kdb_mdr - This function implements the guts of the 'mdr', memory
+ * read command.
+ *	mdr  <addr arg>,<byte count>
+ * Inputs:
+ *	addr	Start address
+ *	count	Number of bytes
+ * Returns:
+ *	Always 0.  Any errors are detected and printed by kdb_getarea.
+ */
+static int kdb_mdr(unsigned long addr, unsigned int count)
+{
+	unsigned char c;
+	while (count--) {
+		if (kdb_getarea(c, addr))
+			return 0;
+		kdb_printf("%02x", c);
+		addr++;
+	}
+	kdb_printf("\n");
+	return 0;
+}
+
+/*
+ * kdb_md - This function implements the 'md', 'md1', 'md2', 'md4',
+ *	'md8' 'mdr' and 'mds' commands.
+ *
+ *	md|mds  [<addr arg> [<line count> [<radix>]]]
+ *	mdWcN	[<addr arg> [<line count> [<radix>]]]
+ *		where W = is the width (1, 2, 4 or 8) and N is the count.
+ *		for eg., md1c20 reads 20 bytes, 1 at a time.
+ *	mdr  <addr arg>,<byte count>
+ */
+static void kdb_md_line(const char *fmtstr, unsigned long addr,
+			int symbolic, int nosect, int bytesperword,
+			int num, int repeat, int phys)
+{
+	/* print just one line of data */
+	kdb_symtab_t symtab;
+	char cbuf[32];
+	char *c = cbuf;
+	int i;
+	int j;
+	unsigned long word;
+
+	memset(cbuf, '\0', sizeof(cbuf));
+	if (phys)
+		kdb_printf("phys " kdb_machreg_fmt0 " ", addr);
+	else
+		kdb_printf(kdb_machreg_fmt0 " ", addr);
+
+	for (i = 0; i < num && repeat--; i++) {
+		if (phys) {
+			if (kdb_getphysword(&word, addr, bytesperword))
+				break;
+		} else if (kdb_getword(&word, addr, bytesperword))
+			break;
+		kdb_printf(fmtstr, word);
+		if (symbolic)
+			kdbnearsym(word, &symtab);
+		else
+			memset(&symtab, 0, sizeof(symtab));
+		if (symtab.sym_name) {
+			kdb_symbol_print(word, &symtab, 0);
+			if (!nosect) {
+				kdb_printf("\n");
+				kdb_printf("                       %s %s "
+					   kdb_machreg_fmt " "
+					   kdb_machreg_fmt " "
+					   kdb_machreg_fmt, symtab.mod_name,
+					   symtab.sec_name, symtab.sec_start,
+					   symtab.sym_start, symtab.sym_end);
+			}
+			addr += bytesperword;
+		} else {
+			union {
+				u64 word;
+				unsigned char c[8];
+			} wc;
+			unsigned char *cp;
+#ifdef	__BIG_ENDIAN
+			cp = wc.c + 8 - bytesperword;
+#else
+			cp = wc.c;
+#endif
+			wc.word = word;
+#define printable_char(c) \
+	({unsigned char __c = c; isascii(__c) && isprint(__c) ? __c : '.'; })
+			for (j = 0; j < bytesperword; j++)
+				*c++ = printable_char(*cp++);
+			addr += bytesperword;
+#undef printable_char
+		}
+	}
+	kdb_printf("%*s %s\n", (int)((num-i)*(2*bytesperword + 1)+1),
+		   " ", cbuf);
+}
+
+static int kdb_md(int argc, const char **argv)
+{
+	static unsigned long last_addr;
+	static int last_radix, last_bytesperword, last_repeat;
+	int radix = 16, mdcount = 8, bytesperword = KDB_WORD_SIZE, repeat;
+	int nosect = 0;
+	char fmtchar, fmtstr[64];
+	unsigned long addr;
+	unsigned long word;
+	long offset = 0;
+	int symbolic = 0;
+	int valid = 0;
+	int phys = 0;
+	int raw = 0;
+
+	kdbgetintenv("MDCOUNT", &mdcount);
+	kdbgetintenv("RADIX", &radix);
+	kdbgetintenv("BYTESPERWORD", &bytesperword);
+
+	/* Assume 'md <addr>' and start with environment values */
+	repeat = mdcount * 16 / bytesperword;
+
+	if (strcmp(argv[0], "mdr") == 0) {
+		if (argc == 2 || (argc == 0 && last_addr != 0))
+			valid = raw = 1;
+		else
+			return KDB_ARGCOUNT;
+	} else if (isdigit(argv[0][2])) {
+		bytesperword = (int)(argv[0][2] - '0');
+		if (bytesperword == 0) {
+			bytesperword = last_bytesperword;
+			if (bytesperword == 0)
+				bytesperword = 4;
+		}
+		last_bytesperword = bytesperword;
+		repeat = mdcount * 16 / bytesperword;
+		if (!argv[0][3])
+			valid = 1;
+		else if (argv[0][3] == 'c' && argv[0][4]) {
+			char *p;
+			repeat = simple_strtoul(argv[0] + 4, &p, 10);
+			mdcount = ((repeat * bytesperword) + 15) / 16;
+			valid = !*p;
+		}
+		last_repeat = repeat;
+	} else if (strcmp(argv[0], "md") == 0)
+		valid = 1;
+	else if (strcmp(argv[0], "mds") == 0)
+		valid = 1;
+	else if (strcmp(argv[0], "mdp") == 0) {
+		phys = valid = 1;
+	}
+	if (!valid)
+		return KDB_NOTFOUND;
+
+	if (argc == 0) {
+		if (last_addr == 0)
+			return KDB_ARGCOUNT;
+		addr = last_addr;
+		radix = last_radix;
+		bytesperword = last_bytesperword;
+		repeat = last_repeat;
+		if (raw)
+			mdcount = repeat;
+		else
+			mdcount = ((repeat * bytesperword) + 15) / 16;
+	}
+
+	if (argc) {
+		unsigned long val;
+		int diag, nextarg = 1;
+		diag = kdbgetaddrarg(argc, argv, &nextarg, &addr,
+				     &offset, NULL);
+		if (diag)
+			return diag;
+		if (argc > nextarg+2)
+			return KDB_ARGCOUNT;
+
+		if (argc >= nextarg) {
+			diag = kdbgetularg(argv[nextarg], &val);
+			if (!diag) {
+				mdcount = (int) val;
+				if (raw)
+					repeat = mdcount;
+				else
+					repeat = mdcount * 16 / bytesperword;
+			}
+		}
+		if (argc >= nextarg+1) {
+			diag = kdbgetularg(argv[nextarg+1], &val);
+			if (!diag)
+				radix = (int) val;
+		}
+	}
+
+	if (strcmp(argv[0], "mdr") == 0) {
+		int ret;
+		last_addr = addr;
+		ret = kdb_mdr(addr, mdcount);
+		last_addr += mdcount;
+		last_repeat = mdcount;
+		last_bytesperword = bytesperword; // to make REPEAT happy
+		return ret;
+	}
+
+	switch (radix) {
+	case 10:
+		fmtchar = 'd';
+		break;
+	case 16:
+		fmtchar = 'x';
+		break;
+	case 8:
+		fmtchar = 'o';
+		break;
+	default:
+		return KDB_BADRADIX;
+	}
+
+	last_radix = radix;
+
+	if (bytesperword > KDB_WORD_SIZE)
+		return KDB_BADWIDTH;
+
+	switch (bytesperword) {
+	case 8:
+		sprintf(fmtstr, "%%16.16l%c ", fmtchar);
+		break;
+	case 4:
+		sprintf(fmtstr, "%%8.8l%c ", fmtchar);
+		break;
+	case 2:
+		sprintf(fmtstr, "%%4.4l%c ", fmtchar);
+		break;
+	case 1:
+		sprintf(fmtstr, "%%2.2l%c ", fmtchar);
+		break;
+	default:
+		return KDB_BADWIDTH;
+	}
+
+	last_repeat = repeat;
+	last_bytesperword = bytesperword;
+
+	if (strcmp(argv[0], "mds") == 0) {
+		symbolic = 1;
+		/* Do not save these changes as last_*, they are temporary mds
+		 * overrides.
+		 */
+		bytesperword = KDB_WORD_SIZE;
+		repeat = mdcount;
+		kdbgetintenv("NOSECT", &nosect);
+	}
+
+	/* Round address down modulo BYTESPERWORD */
+
+	addr &= ~(bytesperword-1);
+
+	while (repeat > 0) {
+		unsigned long a;
+		int n, z, num = (symbolic ? 1 : (16 / bytesperword));
+
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+		for (a = addr, z = 0; z < repeat; a += bytesperword, ++z) {
+			if (phys) {
+				if (kdb_getphysword(&word, a, bytesperword)
+						|| word)
+					break;
+			} else if (kdb_getword(&word, a, bytesperword) || word)
+				break;
+		}
+		n = min(num, repeat);
+		kdb_md_line(fmtstr, addr, symbolic, nosect, bytesperword,
+			    num, repeat, phys);
+		addr += bytesperword * n;
+		repeat -= n;
+		z = (z + num - 1) / num;
+		if (z > 2) {
+			int s = num * (z-2);
+			kdb_printf(kdb_machreg_fmt0 "-" kdb_machreg_fmt0
+				   " zero suppressed\n",
+				addr, addr + bytesperword * s - 1);
+			addr += bytesperword * s;
+			repeat -= s;
+		}
+	}
+	last_addr = addr;
+
+	return 0;
+}
+
+/*
+ * kdb_mm - This function implements the 'mm' command.
+ *	mm address-expression new-value
+ * Remarks:
+ *	mm works on machine words, mmW works on bytes.
+ */
+static int kdb_mm(int argc, const char **argv)
+{
+	int diag;
+	unsigned long addr;
+	long offset = 0;
+	unsigned long contents;
+	int nextarg;
+	int width;
+
+	if (argv[0][2] && !isdigit(argv[0][2]))
+		return KDB_NOTFOUND;
+
+	if (argc < 2)
+		return KDB_ARGCOUNT;
+
+	nextarg = 1;
+	diag = kdbgetaddrarg(argc, argv, &nextarg, &addr, &offset, NULL);
+	if (diag)
+		return diag;
+
+	if (nextarg > argc)
+		return KDB_ARGCOUNT;
+	diag = kdbgetaddrarg(argc, argv, &nextarg, &contents, NULL, NULL);
+	if (diag)
+		return diag;
+
+	if (nextarg != argc + 1)
+		return KDB_ARGCOUNT;
+
+	width = argv[0][2] ? (argv[0][2] - '0') : (KDB_WORD_SIZE);
+	diag = kdb_putword(addr, contents, width);
+	if (diag)
+		return diag;
+
+	kdb_printf(kdb_machreg_fmt " = " kdb_machreg_fmt "\n", addr, contents);
+
+	return 0;
+}
+
+/*
+ * kdb_go - This function implements the 'go' command.
+ *	go [address-expression]
+ */
+static int kdb_go(int argc, const char **argv)
+{
+	unsigned long addr;
+	int diag;
+	int nextarg;
+	long offset;
+
+	if (raw_smp_processor_id() != kdb_initial_cpu) {
+		kdb_printf("go must execute on the entry cpu, "
+			   "please use \"cpu %d\" and then execute go\n",
+			   kdb_initial_cpu);
+		return KDB_BADCPUNUM;
+	}
+	if (argc == 1) {
+		nextarg = 1;
+		diag = kdbgetaddrarg(argc, argv, &nextarg,
+				     &addr, &offset, NULL);
+		if (diag)
+			return diag;
+	} else if (argc) {
+		return KDB_ARGCOUNT;
+	}
+
+	diag = KDB_CMD_GO;
+	if (KDB_FLAG(CATASTROPHIC)) {
+		kdb_printf("Catastrophic error detected\n");
+		kdb_printf("kdb_continue_catastrophic=%d, ",
+			kdb_continue_catastrophic);
+		if (kdb_continue_catastrophic == 0 && kdb_go_count++ == 0) {
+			kdb_printf("type go a second time if you really want "
+				   "to continue\n");
+			return 0;
+		}
+		if (kdb_continue_catastrophic == 2) {
+			kdb_printf("forcing reboot\n");
+			kdb_reboot(0, NULL);
+		}
+		kdb_printf("attempting to continue\n");
+	}
+	return diag;
+}
+
+/*
+ * kdb_rd - This function implements the 'rd' command.
+ */
+static int kdb_rd(int argc, const char **argv)
+{
+	int len = kdb_check_regs();
+#if DBG_MAX_REG_NUM > 0
+	int i;
+	char *rname;
+	int rsize;
+	u64 reg64;
+	u32 reg32;
+	u16 reg16;
+	u8 reg8;
+
+	if (len)
+		return len;
+
+	for (i = 0; i < DBG_MAX_REG_NUM; i++) {
+		rsize = dbg_reg_def[i].size * 2;
+		if (rsize > 16)
+			rsize = 2;
+		if (len + strlen(dbg_reg_def[i].name) + 4 + rsize > 80) {
+			len = 0;
+			kdb_printf("\n");
+		}
+		if (len)
+			len += kdb_printf("  ");
+		switch(dbg_reg_def[i].size * 8) {
+		case 8:
+			rname = dbg_get_reg(i, &reg8, kdb_current_regs);
+			if (!rname)
+				break;
+			len += kdb_printf("%s: %02x", rname, reg8);
+			break;
+		case 16:
+			rname = dbg_get_reg(i, &reg16, kdb_current_regs);
+			if (!rname)
+				break;
+			len += kdb_printf("%s: %04x", rname, reg16);
+			break;
+		case 32:
+			rname = dbg_get_reg(i, &reg32, kdb_current_regs);
+			if (!rname)
+				break;
+			len += kdb_printf("%s: %08x", rname, reg32);
+			break;
+		case 64:
+			rname = dbg_get_reg(i, &reg64, kdb_current_regs);
+			if (!rname)
+				break;
+			len += kdb_printf("%s: %016llx", rname, reg64);
+			break;
+		default:
+			len += kdb_printf("%s: ??", dbg_reg_def[i].name);
+		}
+	}
+	kdb_printf("\n");
+#else
+	if (len)
+		return len;
+
+	kdb_dumpregs(kdb_current_regs);
+#endif
+	return 0;
+}
+
+/*
+ * kdb_rm - This function implements the 'rm' (register modify)  command.
+ *	rm register-name new-contents
+ * Remarks:
+ *	Allows register modification with the same restrictions as gdb
+ */
+static int kdb_rm(int argc, const char **argv)
+{
+#if DBG_MAX_REG_NUM > 0
+	int diag;
+	const char *rname;
+	int i;
+	u64 reg64;
+	u32 reg32;
+	u16 reg16;
+	u8 reg8;
+
+	if (argc != 2)
+		return KDB_ARGCOUNT;
+	/*
+	 * Allow presence or absence of leading '%' symbol.
+	 */
+	rname = argv[1];
+	if (*rname == '%')
+		rname++;
+
+	diag = kdbgetu64arg(argv[2], &reg64);
+	if (diag)
+		return diag;
+
+	diag = kdb_check_regs();
+	if (diag)
+		return diag;
+
+	diag = KDB_BADREG;
+	for (i = 0; i < DBG_MAX_REG_NUM; i++) {
+		if (strcmp(rname, dbg_reg_def[i].name) == 0) {
+			diag = 0;
+			break;
+		}
+	}
+	if (!diag) {
+		switch(dbg_reg_def[i].size * 8) {
+		case 8:
+			reg8 = reg64;
+			dbg_set_reg(i, &reg8, kdb_current_regs);
+			break;
+		case 16:
+			reg16 = reg64;
+			dbg_set_reg(i, &reg16, kdb_current_regs);
+			break;
+		case 32:
+			reg32 = reg64;
+			dbg_set_reg(i, &reg32, kdb_current_regs);
+			break;
+		case 64:
+			dbg_set_reg(i, &reg64, kdb_current_regs);
+			break;
+		}
+	}
+	return diag;
+#else
+	kdb_printf("ERROR: Register set currently not implemented\n");
+    return 0;
+#endif
+}
+
+#if defined(CONFIG_MAGIC_SYSRQ)
+/*
+ * kdb_sr - This function implements the 'sr' (SYSRQ key) command
+ *	which interfaces to the soi-disant MAGIC SYSRQ functionality.
+ *		sr <magic-sysrq-code>
+ */
+static int kdb_sr(int argc, const char **argv)
+{
+	bool check_mask =
+	    !kdb_check_flags(KDB_ENABLE_ALL, kdb_cmd_enabled, false);
+
+	if (argc != 1)
+		return KDB_ARGCOUNT;
+
+	kdb_trap_printk++;
+	__handle_sysrq(*argv[1], check_mask);
+	kdb_trap_printk--;
+
+	return 0;
+}
+#endif	/* CONFIG_MAGIC_SYSRQ */
+
+/*
+ * kdb_ef - This function implements the 'regs' (display exception
+ *	frame) command.  This command takes an address and expects to
+ *	find an exception frame at that address, formats and prints
+ *	it.
+ *		regs address-expression
+ * Remarks:
+ *	Not done yet.
+ */
+static int kdb_ef(int argc, const char **argv)
+{
+	int diag;
+	unsigned long addr;
+	long offset;
+	int nextarg;
+
+	if (argc != 1)
+		return KDB_ARGCOUNT;
+
+	nextarg = 1;
+	diag = kdbgetaddrarg(argc, argv, &nextarg, &addr, &offset, NULL);
+	if (diag)
+		return diag;
+	show_regs((struct pt_regs *)addr);
+	return 0;
+}
+
+/*
+ * kdb_env - This function implements the 'env' command.  Display the
+ *	current environment variables.
+ */
+
+static int kdb_env(int argc, const char **argv)
+{
+	kdb_printenv();
+
+	if (KDB_DEBUG(MASK))
+		kdb_printf("KDBDEBUG=0x%x\n",
+			(kdb_flags & KDB_DEBUG(MASK)) >> KDB_DEBUG_FLAG_SHIFT);
+
+	return 0;
+}
+
+#ifdef CONFIG_PRINTK
+/*
+ * kdb_dmesg - This function implements the 'dmesg' command to display
+ *	the contents of the syslog buffer.
+ *		dmesg [lines] [adjust]
+ */
+static int kdb_dmesg(int argc, const char **argv)
+{
+	int diag;
+	int logging;
+	int lines = 0;
+	int adjust = 0;
+	int n = 0;
+	int skip = 0;
+	struct kmsg_dump_iter iter;
+	size_t len;
+	char buf[201];
+
+	if (argc > 2)
+		return KDB_ARGCOUNT;
+	if (argc) {
+		char *cp;
+		lines = simple_strtol(argv[1], &cp, 0);
+		if (*cp)
+			lines = 0;
+		if (argc > 1) {
+			adjust = simple_strtoul(argv[2], &cp, 0);
+			if (*cp || adjust < 0)
+				adjust = 0;
+		}
+	}
+
+	/* disable LOGGING if set */
+	diag = kdbgetintenv("LOGGING", &logging);
+	if (!diag && logging) {
+		const char *setargs[] = { "set", "LOGGING", "0" };
+		kdb_set(2, setargs);
+	}
+
+	kmsg_dump_rewind(&iter);
+	while (kmsg_dump_get_line(&iter, 1, NULL, 0, NULL))
+		n++;
+
+	if (lines < 0) {
+		if (adjust >= n)
+			kdb_printf("buffer only contains %d lines, nothing "
+				   "printed\n", n);
+		else if (adjust - lines >= n)
+			kdb_printf("buffer only contains %d lines, last %d "
+				   "lines printed\n", n, n - adjust);
+		skip = adjust;
+		lines = abs(lines);
+	} else if (lines > 0) {
+		skip = n - lines - adjust;
+		lines = abs(lines);
+		if (adjust >= n) {
+			kdb_printf("buffer only contains %d lines, "
+				   "nothing printed\n", n);
+			skip = n;
+		} else if (skip < 0) {
+			lines += skip;
+			skip = 0;
+			kdb_printf("buffer only contains %d lines, first "
+				   "%d lines printed\n", n, lines);
+		}
+	} else {
+		lines = n;
+	}
+
+	if (skip >= n || skip < 0)
+		return 0;
+
+	kmsg_dump_rewind(&iter);
+	while (kmsg_dump_get_line(&iter, 1, buf, sizeof(buf), &len)) {
+		if (skip) {
+			skip--;
+			continue;
+		}
+		if (!lines--)
+			break;
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+
+		kdb_printf("%.*s\n", (int)len - 1, buf);
+	}
+
+	return 0;
+}
+#endif /* CONFIG_PRINTK */
+
+/* Make sure we balance enable/disable calls, must disable first. */
+static atomic_t kdb_nmi_disabled;
+
+static int kdb_disable_nmi(int argc, const char *argv[])
+{
+	if (atomic_read(&kdb_nmi_disabled))
+		return 0;
+	atomic_set(&kdb_nmi_disabled, 1);
+	arch_kgdb_ops.enable_nmi(0);
+	return 0;
+}
+
+static int kdb_param_enable_nmi(const char *val, const struct kernel_param *kp)
+{
+	if (!atomic_add_unless(&kdb_nmi_disabled, -1, 0))
+		return -EINVAL;
+	arch_kgdb_ops.enable_nmi(1);
+	return 0;
+}
+
+static const struct kernel_param_ops kdb_param_ops_enable_nmi = {
+	.set = kdb_param_enable_nmi,
+};
+module_param_cb(enable_nmi, &kdb_param_ops_enable_nmi, NULL, 0600);
+
+/*
+ * kdb_cpu - This function implements the 'cpu' command.
+ *	cpu	[<cpunum>]
+ * Returns:
+ *	KDB_CMD_CPU for success, a kdb diagnostic if error
+ */
+static void kdb_cpu_status(void)
+{
+	int i, start_cpu, first_print = 1;
+	char state, prev_state = '?';
+
+	kdb_printf("Currently on cpu %d\n", raw_smp_processor_id());
+	kdb_printf("Available cpus: ");
+	for (start_cpu = -1, i = 0; i < NR_CPUS; i++) {
+		if (!cpu_online(i)) {
+			state = 'F';	/* cpu is offline */
+		} else if (!kgdb_info[i].enter_kgdb) {
+			state = 'D';	/* cpu is online but unresponsive */
+		} else {
+			state = ' ';	/* cpu is responding to kdb */
+			if (kdb_task_state_char(KDB_TSK(i)) == '-')
+				state = '-';	/* idle task */
+		}
+		if (state != prev_state) {
+			if (prev_state != '?') {
+				if (!first_print)
+					kdb_printf(", ");
+				first_print = 0;
+				kdb_printf("%d", start_cpu);
+				if (start_cpu < i-1)
+					kdb_printf("-%d", i-1);
+				if (prev_state != ' ')
+					kdb_printf("(%c)", prev_state);
+			}
+			prev_state = state;
+			start_cpu = i;
+		}
+	}
+	/* print the trailing cpus, ignoring them if they are all offline */
+	if (prev_state != 'F') {
+		if (!first_print)
+			kdb_printf(", ");
+		kdb_printf("%d", start_cpu);
+		if (start_cpu < i-1)
+			kdb_printf("-%d", i-1);
+		if (prev_state != ' ')
+			kdb_printf("(%c)", prev_state);
+	}
+	kdb_printf("\n");
+}
+
+static int kdb_cpu(int argc, const char **argv)
+{
+	unsigned long cpunum;
+	int diag;
+
+	if (argc == 0) {
+		kdb_cpu_status();
+		return 0;
+	}
+
+	if (argc != 1)
+		return KDB_ARGCOUNT;
+
+	diag = kdbgetularg(argv[1], &cpunum);
+	if (diag)
+		return diag;
+
+	/*
+	 * Validate cpunum
+	 */
+	if ((cpunum >= CONFIG_NR_CPUS) || !kgdb_info[cpunum].enter_kgdb)
+		return KDB_BADCPUNUM;
+
+	dbg_switch_cpu = cpunum;
+
+	/*
+	 * Switch to other cpu
+	 */
+	return KDB_CMD_CPU;
+}
+
+/* The user may not realize that ps/bta with no parameters does not print idle
+ * or sleeping system daemon processes, so tell them how many were suppressed.
+ */
+void kdb_ps_suppressed(void)
+{
+	int idle = 0, daemon = 0;
+	unsigned long cpu;
+	const struct task_struct *p, *g;
+	for_each_online_cpu(cpu) {
+		p = kdb_curr_task(cpu);
+		if (kdb_task_state(p, "-"))
+			++idle;
+	}
+	for_each_process_thread(g, p) {
+		if (kdb_task_state(p, "ims"))
+			++daemon;
+	}
+	if (idle || daemon) {
+		if (idle)
+			kdb_printf("%d idle process%s (state -)%s\n",
+				   idle, idle == 1 ? "" : "es",
+				   daemon ? " and " : "");
+		if (daemon)
+			kdb_printf("%d sleeping system daemon (state [ims]) "
+				   "process%s", daemon,
+				   daemon == 1 ? "" : "es");
+		kdb_printf(" suppressed,\nuse 'ps A' to see all.\n");
+	}
+}
+
+void kdb_ps1(const struct task_struct *p)
+{
+	int cpu;
+	unsigned long tmp;
+
+	if (!p ||
+	    copy_from_kernel_nofault(&tmp, (char *)p, sizeof(unsigned long)))
+		return;
+
+	cpu = kdb_process_cpu(p);
+	kdb_printf("0x%px %8d %8d  %d %4d   %c  0x%px %c%s\n",
+		   (void *)p, p->pid, p->parent->pid,
+		   kdb_task_has_cpu(p), kdb_process_cpu(p),
+		   kdb_task_state_char(p),
+		   (void *)(&p->thread),
+		   p == kdb_curr_task(raw_smp_processor_id()) ? '*' : ' ',
+		   p->comm);
+	if (kdb_task_has_cpu(p)) {
+		if (!KDB_TSK(cpu)) {
+			kdb_printf("  Error: no saved data for this cpu\n");
+		} else {
+			if (KDB_TSK(cpu) != p)
+				kdb_printf("  Error: does not match running "
+				   "process table (0x%px)\n", KDB_TSK(cpu));
+		}
+	}
+}
+
+/*
+ * kdb_ps - This function implements the 'ps' command which shows a
+ *	    list of the active processes.
+ *
+ * ps [<state_chars>]   Show processes, optionally selecting only those whose
+ *                      state character is found in <state_chars>.
+ */
+static int kdb_ps(int argc, const char **argv)
+{
+	struct task_struct *g, *p;
+	const char *mask;
+	unsigned long cpu;
+
+	if (argc == 0)
+		kdb_ps_suppressed();
+	kdb_printf("%-*s      Pid   Parent [*] cpu State %-*s Command\n",
+		(int)(2*sizeof(void *))+2, "Task Addr",
+		(int)(2*sizeof(void *))+2, "Thread");
+	mask = argc ? argv[1] : kdbgetenv("PS");
+	/* Run the active tasks first */
+	for_each_online_cpu(cpu) {
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+		p = kdb_curr_task(cpu);
+		if (kdb_task_state(p, mask))
+			kdb_ps1(p);
+	}
+	kdb_printf("\n");
+	/* Now the real tasks */
+	for_each_process_thread(g, p) {
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+		if (kdb_task_state(p, mask))
+			kdb_ps1(p);
+	}
+
+	return 0;
+}
+
+/*
+ * kdb_pid - This function implements the 'pid' command which switches
+ *	the currently active process.
+ *		pid [<pid> | R]
+ */
+static int kdb_pid(int argc, const char **argv)
+{
+	struct task_struct *p;
+	unsigned long val;
+	int diag;
+
+	if (argc > 1)
+		return KDB_ARGCOUNT;
+
+	if (argc) {
+		if (strcmp(argv[1], "R") == 0) {
+			p = KDB_TSK(kdb_initial_cpu);
+		} else {
+			diag = kdbgetularg(argv[1], &val);
+			if (diag)
+				return KDB_BADINT;
+
+			p = find_task_by_pid_ns((pid_t)val,	&init_pid_ns);
+			if (!p) {
+				kdb_printf("No task with pid=%d\n", (pid_t)val);
+				return 0;
+			}
+		}
+		kdb_set_current_task(p);
+	}
+	kdb_printf("KDB current process is %s(pid=%d)\n",
+		   kdb_current_task->comm,
+		   kdb_current_task->pid);
+
+	return 0;
+}
+
+static int kdb_kgdb(int argc, const char **argv)
+{
+	return KDB_CMD_KGDB;
+}
+
+/*
+ * kdb_help - This function implements the 'help' and '?' commands.
+ */
+static int kdb_help(int argc, const char **argv)
+{
+	kdbtab_t *kt;
+
+	kdb_printf("%-15.15s %-20.20s %s\n", "Command", "Usage", "Description");
+	kdb_printf("-----------------------------"
+		   "-----------------------------\n");
+	list_for_each_entry(kt, &kdb_cmds_head, list_node) {
+		char *space = "";
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+		if (!kdb_check_flags(kt->flags, kdb_cmd_enabled, true))
+			continue;
+		if (strlen(kt->usage) > 20)
+			space = "\n                                    ";
+		kdb_printf("%-15.15s %-20s%s%s\n", kt->name,
+			   kt->usage, space, kt->help);
+	}
+	return 0;
+}
+
+/*
+ * kdb_kill - This function implements the 'kill' commands.
+ */
+static int kdb_kill(int argc, const char **argv)
+{
+	long sig, pid;
+	char *endp;
+	struct task_struct *p;
+
+	if (argc != 2)
+		return KDB_ARGCOUNT;
+
+	sig = simple_strtol(argv[1], &endp, 0);
+	if (*endp)
+		return KDB_BADINT;
+	if ((sig >= 0) || !valid_signal(-sig)) {
+		kdb_printf("Invalid signal parameter.<-signal>\n");
+		return 0;
+	}
+	sig = -sig;
+
+	pid = simple_strtol(argv[2], &endp, 0);
+	if (*endp)
+		return KDB_BADINT;
+	if (pid <= 0) {
+		kdb_printf("Process ID must be large than 0.\n");
+		return 0;
+	}
+
+	/* Find the process. */
+	p = find_task_by_pid_ns(pid, &init_pid_ns);
+	if (!p) {
+		kdb_printf("The specified process isn't found.\n");
+		return 0;
+	}
+	p = p->group_leader;
+	kdb_send_sig(p, sig);
+	return 0;
+}
+
+/*
+ * Most of this code has been lifted from kernel/timer.c::sys_sysinfo().
+ * I cannot call that code directly from kdb, it has an unconditional
+ * cli()/sti() and calls routines that take locks which can stop the debugger.
+ */
+static void kdb_sysinfo(struct sysinfo *val)
+{
+	u64 uptime = ktime_get_mono_fast_ns();
+
+	memset(val, 0, sizeof(*val));
+	val->uptime = div_u64(uptime, NSEC_PER_SEC);
+	val->loads[0] = avenrun[0];
+	val->loads[1] = avenrun[1];
+	val->loads[2] = avenrun[2];
+	val->procs = nr_threads-1;
+	si_meminfo(val);
+
+	return;
+}
+
+/*
+ * kdb_summary - This function implements the 'summary' command.
+ */
+static int kdb_summary(int argc, const char **argv)
+{
+	time64_t now;
+	struct sysinfo val;
+
+	if (argc)
+		return KDB_ARGCOUNT;
+
+	kdb_printf("sysname    %s\n", init_uts_ns.name.sysname);
+	kdb_printf("release    %s\n", init_uts_ns.name.release);
+	kdb_printf("version    %s\n", init_uts_ns.name.version);
+	kdb_printf("machine    %s\n", init_uts_ns.name.machine);
+	kdb_printf("nodename   %s\n", init_uts_ns.name.nodename);
+	kdb_printf("domainname %s\n", init_uts_ns.name.domainname);
+
+	now = __ktime_get_real_seconds();
+	kdb_printf("date       %ptTs tz_minuteswest %d\n", &now, sys_tz.tz_minuteswest);
+	kdb_sysinfo(&val);
+	kdb_printf("uptime     ");
+	if (val.uptime > (24*60*60)) {
+		int days = val.uptime / (24*60*60);
+		val.uptime %= (24*60*60);
+		kdb_printf("%d day%s ", days, days == 1 ? "" : "s");
+	}
+	kdb_printf("%02ld:%02ld\n", val.uptime/(60*60), (val.uptime/60)%60);
+
+	kdb_printf("load avg   %ld.%02ld %ld.%02ld %ld.%02ld\n",
+		LOAD_INT(val.loads[0]), LOAD_FRAC(val.loads[0]),
+		LOAD_INT(val.loads[1]), LOAD_FRAC(val.loads[1]),
+		LOAD_INT(val.loads[2]), LOAD_FRAC(val.loads[2]));
+
+	/* Display in kilobytes */
+#define K(x) ((x) << (PAGE_SHIFT - 10))
+	kdb_printf("\nMemTotal:       %8lu kB\nMemFree:        %8lu kB\n"
+		   "Buffers:        %8lu kB\n",
+		   K(val.totalram), K(val.freeram), K(val.bufferram));
+	return 0;
+}
+
+/*
+ * kdb_per_cpu - This function implements the 'per_cpu' command.
+ */
+static int kdb_per_cpu(int argc, const char **argv)
+{
+	char fmtstr[64];
+	int cpu, diag, nextarg = 1;
+	unsigned long addr, symaddr, val, bytesperword = 0, whichcpu = ~0UL;
+
+	if (argc < 1 || argc > 3)
+		return KDB_ARGCOUNT;
+
+	diag = kdbgetaddrarg(argc, argv, &nextarg, &symaddr, NULL, NULL);
+	if (diag)
+		return diag;
+
+	if (argc >= 2) {
+		diag = kdbgetularg(argv[2], &bytesperword);
+		if (diag)
+			return diag;
+	}
+	if (!bytesperword)
+		bytesperword = KDB_WORD_SIZE;
+	else if (bytesperword > KDB_WORD_SIZE)
+		return KDB_BADWIDTH;
+	sprintf(fmtstr, "%%0%dlx ", (int)(2*bytesperword));
+	if (argc >= 3) {
+		diag = kdbgetularg(argv[3], &whichcpu);
+		if (diag)
+			return diag;
+		if (whichcpu >= nr_cpu_ids || !cpu_online(whichcpu)) {
+			kdb_printf("cpu %ld is not online\n", whichcpu);
+			return KDB_BADCPUNUM;
+		}
+	}
+
+	/* Most architectures use __per_cpu_offset[cpu], some use
+	 * __per_cpu_offset(cpu), smp has no __per_cpu_offset.
+	 */
+#ifdef	__per_cpu_offset
+#define KDB_PCU(cpu) __per_cpu_offset(cpu)
+#else
+#ifdef	CONFIG_SMP
+#define KDB_PCU(cpu) __per_cpu_offset[cpu]
+#else
+#define KDB_PCU(cpu) 0
+#endif
+#endif
+	for_each_online_cpu(cpu) {
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+
+		if (whichcpu != ~0UL && whichcpu != cpu)
+			continue;
+		addr = symaddr + KDB_PCU(cpu);
+		diag = kdb_getword(&val, addr, bytesperword);
+		if (diag) {
+			kdb_printf("%5d " kdb_bfd_vma_fmt0 " - unable to "
+				   "read, diag=%d\n", cpu, addr, diag);
+			continue;
+		}
+		kdb_printf("%5d ", cpu);
+		kdb_md_line(fmtstr, addr,
+			bytesperword == KDB_WORD_SIZE,
+			1, bytesperword, 1, 1, 0);
+	}
+#undef KDB_PCU
+	return 0;
+}
+
+/*
+ * display help for the use of cmd | grep pattern
+ */
+static int kdb_grep_help(int argc, const char **argv)
+{
+	kdb_printf("Usage of  cmd args | grep pattern:\n");
+	kdb_printf("  Any command's output may be filtered through an ");
+	kdb_printf("emulated 'pipe'.\n");
+	kdb_printf("  'grep' is just a key word.\n");
+	kdb_printf("  The pattern may include a very limited set of "
+		   "metacharacters:\n");
+	kdb_printf("   pattern or ^pattern or pattern$ or ^pattern$\n");
+	kdb_printf("  And if there are spaces in the pattern, you may "
+		   "quote it:\n");
+	kdb_printf("   \"pat tern\" or \"^pat tern\" or \"pat tern$\""
+		   " or \"^pat tern$\"\n");
+	return 0;
+}
+
+/**
+ * kdb_register() - This function is used to register a kernel debugger
+ *                  command.
+ * @cmd: pointer to kdb command
+ *
+ * Note that it's the job of the caller to keep the memory for the cmd
+ * allocated until unregister is called.
+ */
+int kdb_register(kdbtab_t *cmd)
+{
+	kdbtab_t *kp;
+
+	list_for_each_entry(kp, &kdb_cmds_head, list_node) {
+		if (strcmp(kp->name, cmd->name) == 0) {
+			kdb_printf("Duplicate kdb cmd: %s, func %p help %s\n",
+				   cmd->name, cmd->func, cmd->help);
+			return 1;
+		}
+	}
+
+	list_add_tail(&cmd->list_node, &kdb_cmds_head);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kdb_register);
+
+/**
+ * kdb_register_table() - This function is used to register a kdb command
+ *                        table.
+ * @kp: pointer to kdb command table
+ * @len: length of kdb command table
+ */
+void kdb_register_table(kdbtab_t *kp, size_t len)
+{
+	while (len--) {
+		list_add_tail(&kp->list_node, &kdb_cmds_head);
+		kp++;
+	}
+}
+
+/**
+ * kdb_unregister() - This function is used to unregister a kernel debugger
+ *                    command. It is generally called when a module which
+ *                    implements kdb command is unloaded.
+ * @cmd: pointer to kdb command
+ */
+void kdb_unregister(kdbtab_t *cmd)
+{
+	list_del(&cmd->list_node);
+}
+EXPORT_SYMBOL_GPL(kdb_unregister);
+
+static kdbtab_t maintab[] = {
+	{	.name = "md",
+		.func = kdb_md,
+		.usage = "<vaddr>",
+		.help = "Display Memory Contents, also mdWcN, e.g. md8c1",
+		.minlen = 1,
+		.flags = KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS,
+	},
+	{	.name = "mdr",
+		.func = kdb_md,
+		.usage = "<vaddr> <bytes>",
+		.help = "Display Raw Memory",
+		.flags = KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS,
+	},
+	{	.name = "mdp",
+		.func = kdb_md,
+		.usage = "<paddr> <bytes>",
+		.help = "Display Physical Memory",
+		.flags = KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS,
+	},
+	{	.name = "mds",
+		.func = kdb_md,
+		.usage = "<vaddr>",
+		.help = "Display Memory Symbolically",
+		.flags = KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS,
+	},
+	{	.name = "mm",
+		.func = kdb_mm,
+		.usage = "<vaddr> <contents>",
+		.help = "Modify Memory Contents",
+		.flags = KDB_ENABLE_MEM_WRITE | KDB_REPEAT_NO_ARGS,
+	},
+	{	.name = "go",
+		.func = kdb_go,
+		.usage = "[<vaddr>]",
+		.help = "Continue Execution",
+		.minlen = 1,
+		.flags = KDB_ENABLE_REG_WRITE |
+			     KDB_ENABLE_ALWAYS_SAFE_NO_ARGS,
+	},
+	{	.name = "rd",
+		.func = kdb_rd,
+		.usage = "",
+		.help = "Display Registers",
+		.flags = KDB_ENABLE_REG_READ,
+	},
+	{	.name = "rm",
+		.func = kdb_rm,
+		.usage = "<reg> <contents>",
+		.help = "Modify Registers",
+		.flags = KDB_ENABLE_REG_WRITE,
+	},
+	{	.name = "ef",
+		.func = kdb_ef,
+		.usage = "<vaddr>",
+		.help = "Display exception frame",
+		.flags = KDB_ENABLE_MEM_READ,
+	},
+	{	.name = "bt",
+		.func = kdb_bt,
+		.usage = "[<vaddr>]",
+		.help = "Stack traceback",
+		.minlen = 1,
+		.flags = KDB_ENABLE_MEM_READ | KDB_ENABLE_INSPECT_NO_ARGS,
+	},
+	{	.name = "btp",
+		.func = kdb_bt,
+		.usage = "<pid>",
+		.help = "Display stack for process <pid>",
+		.flags = KDB_ENABLE_INSPECT,
+	},
+	{	.name = "bta",
+		.func = kdb_bt,
+		.usage = "[<state_chars>|A]",
+		.help = "Backtrace all processes whose state matches",
+		.flags = KDB_ENABLE_INSPECT,
+	},
+	{	.name = "btc",
+		.func = kdb_bt,
+		.usage = "",
+		.help = "Backtrace current process on each cpu",
+		.flags = KDB_ENABLE_INSPECT,
+	},
+	{	.name = "btt",
+		.func = kdb_bt,
+		.usage = "<vaddr>",
+		.help = "Backtrace process given its struct task address",
+		.flags = KDB_ENABLE_MEM_READ | KDB_ENABLE_INSPECT_NO_ARGS,
+	},
+	{	.name = "env",
+		.func = kdb_env,
+		.usage = "",
+		.help = "Show environment variables",
+		.flags = KDB_ENABLE_ALWAYS_SAFE,
+	},
+	{	.name = "set",
+		.func = kdb_set,
+		.usage = "",
+		.help = "Set environment variables",
+		.flags = KDB_ENABLE_ALWAYS_SAFE,
+	},
+	{	.name = "help",
+		.func = kdb_help,
+		.usage = "",
+		.help = "Display Help Message",
+		.minlen = 1,
+		.flags = KDB_ENABLE_ALWAYS_SAFE,
+	},
+	{	.name = "?",
+		.func = kdb_help,
+		.usage = "",
+		.help = "Display Help Message",
+		.flags = KDB_ENABLE_ALWAYS_SAFE,
+	},
+	{	.name = "cpu",
+		.func = kdb_cpu,
+		.usage = "<cpunum>",
+		.help = "Switch to new cpu",
+		.flags = KDB_ENABLE_ALWAYS_SAFE_NO_ARGS,
+	},
+	{	.name = "kgdb",
+		.func = kdb_kgdb,
+		.usage = "",
+		.help = "Enter kgdb mode",
+		.flags = 0,
+	},
+	{	.name = "ps",
+		.func = kdb_ps,
+		.usage = "[<state_chars>|A]",
+		.help = "Display active task list",
+		.flags = KDB_ENABLE_INSPECT,
+	},
+	{	.name = "pid",
+		.func = kdb_pid,
+		.usage = "<pidnum>",
+		.help = "Switch to another task",
+		.flags = KDB_ENABLE_INSPECT,
+	},
+	{	.name = "reboot",
+		.func = kdb_reboot,
+		.usage = "",
+		.help = "Reboot the machine immediately",
+		.flags = KDB_ENABLE_REBOOT,
+	},
+#if defined(CONFIG_MODULES)
+	{	.name = "lsmod",
+		.func = kdb_lsmod,
+		.usage = "",
+		.help = "List loaded kernel modules",
+		.flags = KDB_ENABLE_INSPECT,
+	},
+#endif
+#if defined(CONFIG_MAGIC_SYSRQ)
+	{	.name = "sr",
+		.func = kdb_sr,
+		.usage = "<key>",
+		.help = "Magic SysRq key",
+		.flags = KDB_ENABLE_ALWAYS_SAFE,
+	},
+#endif
+#if defined(CONFIG_PRINTK)
+	{	.name = "dmesg",
+		.func = kdb_dmesg,
+		.usage = "[lines]",
+		.help = "Display syslog buffer",
+		.flags = KDB_ENABLE_ALWAYS_SAFE,
+	},
+#endif
+	{	.name = "defcmd",
+		.func = kdb_defcmd,
+		.usage = "name \"usage\" \"help\"",
+		.help = "Define a set of commands, down to endefcmd",
+		/*
+		 * Macros are always safe because when executed each
+		 * internal command re-enters kdb_parse() and is safety
+		 * checked individually.
+		 */
+		.flags = KDB_ENABLE_ALWAYS_SAFE,
+	},
+	{	.name = "kill",
+		.func = kdb_kill,
+		.usage = "<-signal> <pid>",
+		.help = "Send a signal to a process",
+		.flags = KDB_ENABLE_SIGNAL,
+	},
+	{	.name = "summary",
+		.func = kdb_summary,
+		.usage = "",
+		.help = "Summarize the system",
+		.minlen = 4,
+		.flags = KDB_ENABLE_ALWAYS_SAFE,
+	},
+	{	.name = "per_cpu",
+		.func = kdb_per_cpu,
+		.usage = "<sym> [<bytes>] [<cpu>]",
+		.help = "Display per_cpu variables",
+		.minlen = 3,
+		.flags = KDB_ENABLE_MEM_READ,
+	},
+	{	.name = "grephelp",
+		.func = kdb_grep_help,
+		.usage = "",
+		.help = "Display help on | grep",
+		.flags = KDB_ENABLE_ALWAYS_SAFE,
+	},
+};
+
+static kdbtab_t nmicmd = {
+	.name = "disable_nmi",
+	.func = kdb_disable_nmi,
+	.usage = "",
+	.help = "Disable NMI entry to KDB",
+	.flags = KDB_ENABLE_ALWAYS_SAFE,
+};
+
+/* Initialize the kdb command table. */
+static void __init kdb_inittab(void)
+{
+	kdb_register_table(maintab, ARRAY_SIZE(maintab));
+	if (arch_kgdb_ops.enable_nmi)
+		kdb_register_table(&nmicmd, 1);
+}
+
+/* Execute any commands defined in kdb_cmds.  */
+static void __init kdb_cmd_init(void)
+{
+	int i, diag;
+	for (i = 0; kdb_cmds[i]; ++i) {
+		diag = kdb_parse(kdb_cmds[i]);
+		if (diag)
+			kdb_printf("kdb command %s failed, kdb diag %d\n",
+				kdb_cmds[i], diag);
+	}
+	if (defcmd_in_progress) {
+		kdb_printf("Incomplete 'defcmd' set, forcing endefcmd\n");
+		kdb_parse("endefcmd");
+	}
+}
+
+/* Initialize kdb_printf, breakpoint tables and kdb state */
+void __init kdb_init(int lvl)
+{
+	static int kdb_init_lvl = KDB_NOT_INITIALIZED;
+	int i;
+
+	if (kdb_init_lvl == KDB_INIT_FULL || lvl <= kdb_init_lvl)
+		return;
+	for (i = kdb_init_lvl; i < lvl; i++) {
+		switch (i) {
+		case KDB_NOT_INITIALIZED:
+			kdb_inittab();		/* Initialize Command Table */
+			kdb_initbptab();	/* Initialize Breakpoints */
+			break;
+		case KDB_INIT_EARLY:
+			kdb_cmd_init();		/* Build kdb_cmds tables */
+			break;
+		}
+	}
+	kdb_init_lvl = lvl;
+}
diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h
new file mode 100644
index 000000000..1f8c519a5
--- /dev/null
+++ b/kernel/debug/kdb/kdb_private.h
@@ -0,0 +1,244 @@
+#ifndef _KDBPRIVATE_H
+#define _KDBPRIVATE_H
+
+/*
+ * Kernel Debugger Architecture Independent Private Headers
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 2000-2004 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ */
+
+#include <linux/kgdb.h>
+#include "../debug_core.h"
+
+/* Kernel Debugger Command codes.  Must not overlap with error codes. */
+#define KDB_CMD_GO	(-1001)
+#define KDB_CMD_CPU	(-1002)
+#define KDB_CMD_SS	(-1003)
+#define KDB_CMD_KGDB (-1005)
+
+/* Internal debug flags */
+#define KDB_DEBUG_FLAG_BP	0x0002	/* Breakpoint subsystem debug */
+#define KDB_DEBUG_FLAG_BB_SUMM	0x0004	/* Basic block analysis, summary only */
+#define KDB_DEBUG_FLAG_AR	0x0008	/* Activation record, generic */
+#define KDB_DEBUG_FLAG_ARA	0x0010	/* Activation record, arch specific */
+#define KDB_DEBUG_FLAG_BB	0x0020	/* All basic block analysis */
+#define KDB_DEBUG_FLAG_STATE	0x0040	/* State flags */
+#define KDB_DEBUG_FLAG_MASK	0xffff	/* All debug flags */
+#define KDB_DEBUG_FLAG_SHIFT	16	/* Shift factor for dbflags */
+
+#define KDB_DEBUG(flag)	(kdb_flags & \
+	(KDB_DEBUG_FLAG_##flag << KDB_DEBUG_FLAG_SHIFT))
+#define KDB_DEBUG_STATE(text, value) if (KDB_DEBUG(STATE)) \
+		kdb_print_state(text, value)
+
+#if BITS_PER_LONG == 32
+
+#define KDB_PLATFORM_ENV	"BYTESPERWORD=4"
+
+#define kdb_machreg_fmt		"0x%lx"
+#define kdb_machreg_fmt0	"0x%08lx"
+#define kdb_bfd_vma_fmt		"0x%lx"
+#define kdb_bfd_vma_fmt0	"0x%08lx"
+#define kdb_elfw_addr_fmt	"0x%x"
+#define kdb_elfw_addr_fmt0	"0x%08x"
+#define kdb_f_count_fmt		"%d"
+
+#elif BITS_PER_LONG == 64
+
+#define KDB_PLATFORM_ENV	"BYTESPERWORD=8"
+
+#define kdb_machreg_fmt		"0x%lx"
+#define kdb_machreg_fmt0	"0x%016lx"
+#define kdb_bfd_vma_fmt		"0x%lx"
+#define kdb_bfd_vma_fmt0	"0x%016lx"
+#define kdb_elfw_addr_fmt	"0x%x"
+#define kdb_elfw_addr_fmt0	"0x%016x"
+#define kdb_f_count_fmt		"%ld"
+
+#endif
+
+/*
+ * KDB_MAXBPT describes the total number of breakpoints
+ * supported by this architecture.
+ */
+#define KDB_MAXBPT	16
+
+/* Symbol table format returned by kallsyms. */
+typedef struct __ksymtab {
+		unsigned long value;	/* Address of symbol */
+		const char *mod_name;	/* Module containing symbol or
+					 * "kernel" */
+		unsigned long mod_start;
+		unsigned long mod_end;
+		const char *sec_name;	/* Section containing symbol */
+		unsigned long sec_start;
+		unsigned long sec_end;
+		const char *sym_name;	/* Full symbol name, including
+					 * any version */
+		unsigned long sym_start;
+		unsigned long sym_end;
+		} kdb_symtab_t;
+extern int kallsyms_symbol_next(char *prefix_name, int flag, int buf_size);
+extern int kallsyms_symbol_complete(char *prefix_name, int max_len);
+
+/* Exported Symbols for kernel loadable modules to use. */
+extern int kdb_getarea_size(void *, unsigned long, size_t);
+extern int kdb_putarea_size(unsigned long, void *, size_t);
+
+/*
+ * Like get_user and put_user, kdb_getarea and kdb_putarea take variable
+ * names, not pointers.  The underlying *_size functions take pointers.
+ */
+#define kdb_getarea(x, addr) kdb_getarea_size(&(x), addr, sizeof((x)))
+#define kdb_putarea(addr, x) kdb_putarea_size(addr, &(x), sizeof((x)))
+
+extern int kdb_getphysword(unsigned long *word,
+			unsigned long addr, size_t size);
+extern int kdb_getword(unsigned long *, unsigned long, size_t);
+extern int kdb_putword(unsigned long, unsigned long, size_t);
+
+extern int kdbgetularg(const char *, unsigned long *);
+extern int kdbgetu64arg(const char *, u64 *);
+extern char *kdbgetenv(const char *);
+extern int kdbgetaddrarg(int, const char **, int*, unsigned long *,
+			 long *, char **);
+extern int kdbgetsymval(const char *, kdb_symtab_t *);
+extern int kdbnearsym(unsigned long, kdb_symtab_t *);
+extern char *kdb_strdup(const char *str, gfp_t type);
+extern void kdb_symbol_print(unsigned long, const kdb_symtab_t *, unsigned int);
+
+/* Routine for debugging the debugger state. */
+extern void kdb_print_state(const char *, int);
+
+extern int kdb_state;
+#define KDB_STATE_KDB		0x00000001	/* Cpu is inside kdb */
+#define KDB_STATE_LEAVING	0x00000002	/* Cpu is leaving kdb */
+#define KDB_STATE_CMD		0x00000004	/* Running a kdb command */
+#define KDB_STATE_KDB_CONTROL	0x00000008	/* This cpu is under
+						 * kdb control */
+#define KDB_STATE_HOLD_CPU	0x00000010	/* Hold this cpu inside kdb */
+#define KDB_STATE_DOING_SS	0x00000020	/* Doing ss command */
+#define KDB_STATE_SSBPT		0x00000080	/* Install breakpoint
+						 * after one ss, independent of
+						 * DOING_SS */
+#define KDB_STATE_REENTRY	0x00000100	/* Valid re-entry into kdb */
+#define KDB_STATE_SUPPRESS	0x00000200	/* Suppress error messages */
+#define KDB_STATE_PAGER		0x00000400	/* pager is available */
+#define KDB_STATE_GO_SWITCH	0x00000800	/* go is switching
+						 * back to initial cpu */
+#define KDB_STATE_WAIT_IPI	0x00002000	/* Waiting for kdb_ipi() NMI */
+#define KDB_STATE_RECURSE	0x00004000	/* Recursive entry to kdb */
+#define KDB_STATE_IP_ADJUSTED	0x00008000	/* Restart IP has been
+						 * adjusted */
+#define KDB_STATE_GO1		0x00010000	/* go only releases one cpu */
+#define KDB_STATE_KEYBOARD	0x00020000	/* kdb entered via
+						 * keyboard on this cpu */
+#define KDB_STATE_KEXEC		0x00040000	/* kexec issued */
+#define KDB_STATE_DOING_KGDB	0x00080000	/* kgdb enter now issued */
+#define KDB_STATE_KGDB_TRANS	0x00200000	/* Transition to kgdb */
+#define KDB_STATE_ARCH		0xff000000	/* Reserved for arch
+						 * specific use */
+
+#define KDB_STATE(flag) (kdb_state & KDB_STATE_##flag)
+#define KDB_STATE_SET(flag) ((void)(kdb_state |= KDB_STATE_##flag))
+#define KDB_STATE_CLEAR(flag) ((void)(kdb_state &= ~KDB_STATE_##flag))
+
+extern int kdb_nextline; /* Current number of lines displayed */
+
+typedef struct _kdb_bp {
+	unsigned long	bp_addr;	/* Address breakpoint is present at */
+	unsigned int	bp_free:1;	/* This entry is available */
+	unsigned int	bp_enabled:1;	/* Breakpoint is active in register */
+	unsigned int	bp_type:4;	/* Uses hardware register */
+	unsigned int	bp_installed:1;	/* Breakpoint is installed */
+	unsigned int	bp_delay:1;	/* Do delayed bp handling */
+	unsigned int	bp_delayed:1;	/* Delayed breakpoint */
+	unsigned int	bph_length;	/* HW break length */
+} kdb_bp_t;
+
+#ifdef CONFIG_KGDB_KDB
+extern kdb_bp_t kdb_breakpoints[/* KDB_MAXBPT */];
+
+extern void kdb_register_table(kdbtab_t *kp, size_t len);
+extern int kdb_bt(int, const char **);	/* KDB display back trace */
+
+/* KDB breakpoint management functions */
+extern void kdb_initbptab(void);
+extern void kdb_bp_install(struct pt_regs *);
+extern void kdb_bp_remove(void);
+
+typedef enum {
+	KDB_DB_BPT,	/* Breakpoint */
+	KDB_DB_SS,	/* Single-step trap */
+	KDB_DB_SSBPT,	/* Single step over breakpoint */
+	KDB_DB_NOBPT	/* Spurious breakpoint */
+} kdb_dbtrap_t;
+
+extern int kdb_main_loop(kdb_reason_t, kdb_reason_t,
+			 int, kdb_dbtrap_t, struct pt_regs *);
+
+/* Miscellaneous functions and data areas */
+extern int kdb_grepping_flag;
+#define KDB_GREPPING_FLAG_SEARCH 0x8000
+extern char kdb_grep_string[];
+#define KDB_GREP_STRLEN 256
+extern int kdb_grep_leading;
+extern int kdb_grep_trailing;
+extern char *kdb_cmds[];
+extern char kdb_task_state_char (const struct task_struct *);
+extern bool kdb_task_state(const struct task_struct *p, const char *mask);
+extern void kdb_ps_suppressed(void);
+extern void kdb_ps1(const struct task_struct *p);
+extern void kdb_send_sig(struct task_struct *p, int sig);
+extern char kdb_getchar(void);
+extern char *kdb_getstr(char *, size_t, const char *);
+extern void kdb_gdb_state_pass(char *buf);
+
+/* Defines for kdb_symbol_print */
+#define KDB_SP_SPACEB	0x0001		/* Space before string */
+#define KDB_SP_SPACEA	0x0002		/* Space after string */
+#define KDB_SP_PAREN	0x0004		/* Parenthesis around string */
+#define KDB_SP_VALUE	0x0008		/* Print the value of the address */
+#define KDB_SP_SYMSIZE	0x0010		/* Print the size of the symbol */
+#define KDB_SP_NEWLINE	0x0020		/* Newline after string */
+#define KDB_SP_DEFAULT (KDB_SP_VALUE|KDB_SP_PAREN)
+
+#define KDB_TSK(cpu) kgdb_info[cpu].task
+#define KDB_TSKREGS(cpu) kgdb_info[cpu].debuggerinfo
+
+extern struct task_struct *kdb_curr_task(int);
+
+#define kdb_task_has_cpu(p) (task_curr(p))
+
+#define GFP_KDB (in_dbg_master() ? GFP_ATOMIC : GFP_KERNEL)
+
+extern struct task_struct *kdb_current_task;
+extern struct pt_regs *kdb_current_regs;
+
+#ifdef CONFIG_KDB_KEYBOARD
+extern void kdb_kbd_cleanup_state(void);
+#else /* ! CONFIG_KDB_KEYBOARD */
+#define kdb_kbd_cleanup_state()
+#endif /* ! CONFIG_KDB_KEYBOARD */
+
+extern char kdb_prompt_str[];
+
+#define	KDB_WORD_SIZE	((int)sizeof(unsigned long))
+
+#endif /* CONFIG_KGDB_KDB */
+
+#define kdb_func_printf(format, args...) \
+	kdb_printf("%s: " format, __func__, ## args)
+
+#define kdb_dbg_printf(mask, format, args...) \
+	do { \
+		if (KDB_DEBUG(mask)) \
+			kdb_func_printf(format, ## args); \
+	} while (0)
+
+#endif	/* !_KDBPRIVATE_H */
diff --git a/kernel/debug/kdb/kdb_support.c b/kernel/debug/kdb/kdb_support.c
new file mode 100644
index 000000000..0a3949714
--- /dev/null
+++ b/kernel/debug/kdb/kdb_support.c
@@ -0,0 +1,556 @@
+/*
+ * Kernel Debugger Architecture Independent Support Functions
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 1999-2004 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ * 03/02/13    added new 2.5 kallsyms <xavier.bru@bull.net>
+ */
+
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/kallsyms.h>
+#include <linux/stddef.h>
+#include <linux/vmalloc.h>
+#include <linux/ptrace.h>
+#include <linux/highmem.h>
+#include <linux/hardirq.h>
+#include <linux/delay.h>
+#include <linux/uaccess.h>
+#include <linux/kdb.h>
+#include <linux/slab.h>
+#include <linux/ctype.h>
+#include "kdb_private.h"
+
+/*
+ * kdbgetsymval - Return the address of the given symbol.
+ *
+ * Parameters:
+ *	symname	Character string containing symbol name
+ *      symtab  Structure to receive results
+ * Returns:
+ *	0	Symbol not found, symtab zero filled
+ *	1	Symbol mapped to module/symbol/section, data in symtab
+ */
+int kdbgetsymval(const char *symname, kdb_symtab_t *symtab)
+{
+	kdb_dbg_printf(AR, "symname=%s, symtab=%px\n", symname, symtab);
+	memset(symtab, 0, sizeof(*symtab));
+	symtab->sym_start = kallsyms_lookup_name(symname);
+	if (symtab->sym_start) {
+		kdb_dbg_printf(AR, "returns 1, symtab->sym_start=0x%lx\n",
+			       symtab->sym_start);
+		return 1;
+	}
+	kdb_dbg_printf(AR, "returns 0\n");
+	return 0;
+}
+EXPORT_SYMBOL(kdbgetsymval);
+
+/**
+ * kdbnearsym() - Return the name of the symbol with the nearest address
+ *                less than @addr.
+ * @addr: Address to check for near symbol
+ * @symtab: Structure to receive results
+ *
+ * WARNING: This function may return a pointer to a single statically
+ * allocated buffer (namebuf). kdb's unusual calling context (single
+ * threaded, all other CPUs halted) provides us sufficient locking for
+ * this to be safe. The only constraint imposed by the static buffer is
+ * that the caller must consume any previous reply prior to another call
+ * to lookup a new symbol.
+ *
+ * Note that, strictly speaking, some architectures may re-enter the kdb
+ * trap if the system turns out to be very badly damaged and this breaks
+ * the single-threaded assumption above. In these circumstances successful
+ * continuation and exit from the inner trap is unlikely to work and any
+ * user attempting this receives a prominent warning before being allowed
+ * to progress. In these circumstances we remain memory safe because
+ * namebuf[KSYM_NAME_LEN-1] will never change from '\0' although we do
+ * tolerate the possibility of garbled symbol display from the outer kdb
+ * trap.
+ *
+ * Return:
+ * * 0 - No sections contain this address, symtab zero filled
+ * * 1 - Address mapped to module/symbol/section, data in symtab
+ */
+int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
+{
+	int ret = 0;
+	unsigned long symbolsize = 0;
+	unsigned long offset = 0;
+	static char namebuf[KSYM_NAME_LEN];
+
+	kdb_dbg_printf(AR, "addr=0x%lx, symtab=%px\n", addr, symtab);
+	memset(symtab, 0, sizeof(*symtab));
+
+	if (addr < 4096)
+		goto out;
+
+	symtab->sym_name = kallsyms_lookup(addr, &symbolsize , &offset,
+				(char **)(&symtab->mod_name), namebuf);
+	if (offset > 8*1024*1024) {
+		symtab->sym_name = NULL;
+		addr = offset = symbolsize = 0;
+	}
+	symtab->sym_start = addr - offset;
+	symtab->sym_end = symtab->sym_start + symbolsize;
+	ret = symtab->sym_name != NULL && *(symtab->sym_name) != '\0';
+
+	if (symtab->mod_name == NULL)
+		symtab->mod_name = "kernel";
+	kdb_dbg_printf(AR, "returns %d symtab->sym_start=0x%lx, symtab->mod_name=%px, symtab->sym_name=%px (%s)\n",
+		       ret, symtab->sym_start, symtab->mod_name, symtab->sym_name, symtab->sym_name);
+out:
+	return ret;
+}
+
+static char ks_namebuf[KSYM_NAME_LEN+1], ks_namebuf_prev[KSYM_NAME_LEN+1];
+
+/*
+ * kallsyms_symbol_complete
+ *
+ * Parameters:
+ *	prefix_name	prefix of a symbol name to lookup
+ *	max_len		maximum length that can be returned
+ * Returns:
+ *	Number of symbols which match the given prefix.
+ * Notes:
+ *	prefix_name is changed to contain the longest unique prefix that
+ *	starts with this prefix (tab completion).
+ */
+int kallsyms_symbol_complete(char *prefix_name, int max_len)
+{
+	loff_t pos = 0;
+	int prefix_len = strlen(prefix_name), prev_len = 0;
+	int i, number = 0;
+	const char *name;
+
+	while ((name = kdb_walk_kallsyms(&pos))) {
+		if (strncmp(name, prefix_name, prefix_len) == 0) {
+			strscpy(ks_namebuf, name, sizeof(ks_namebuf));
+			/* Work out the longest name that matches the prefix */
+			if (++number == 1) {
+				prev_len = min_t(int, max_len-1,
+						 strlen(ks_namebuf));
+				memcpy(ks_namebuf_prev, ks_namebuf, prev_len);
+				ks_namebuf_prev[prev_len] = '\0';
+				continue;
+			}
+			for (i = 0; i < prev_len; i++) {
+				if (ks_namebuf[i] != ks_namebuf_prev[i]) {
+					prev_len = i;
+					ks_namebuf_prev[i] = '\0';
+					break;
+				}
+			}
+		}
+	}
+	if (prev_len > prefix_len)
+		memcpy(prefix_name, ks_namebuf_prev, prev_len+1);
+	return number;
+}
+
+/*
+ * kallsyms_symbol_next
+ *
+ * Parameters:
+ *	prefix_name	prefix of a symbol name to lookup
+ *	flag	0 means search from the head, 1 means continue search.
+ *	buf_size	maximum length that can be written to prefix_name
+ *			buffer
+ * Returns:
+ *	1 if a symbol matches the given prefix.
+ *	0 if no string found
+ */
+int kallsyms_symbol_next(char *prefix_name, int flag, int buf_size)
+{
+	int prefix_len = strlen(prefix_name);
+	static loff_t pos;
+	const char *name;
+
+	if (!flag)
+		pos = 0;
+
+	while ((name = kdb_walk_kallsyms(&pos))) {
+		if (!strncmp(name, prefix_name, prefix_len))
+			return strscpy(prefix_name, name, buf_size);
+	}
+	return 0;
+}
+
+/*
+ * kdb_symbol_print - Standard method for printing a symbol name and offset.
+ * Inputs:
+ *	addr	Address to be printed.
+ *	symtab	Address of symbol data, if NULL this routine does its
+ *		own lookup.
+ *	punc	Punctuation for string, bit field.
+ * Remarks:
+ *	The string and its punctuation is only printed if the address
+ *	is inside the kernel, except that the value is always printed
+ *	when requested.
+ */
+void kdb_symbol_print(unsigned long addr, const kdb_symtab_t *symtab_p,
+		      unsigned int punc)
+{
+	kdb_symtab_t symtab, *symtab_p2;
+	if (symtab_p) {
+		symtab_p2 = (kdb_symtab_t *)symtab_p;
+	} else {
+		symtab_p2 = &symtab;
+		kdbnearsym(addr, symtab_p2);
+	}
+	if (!(symtab_p2->sym_name || (punc & KDB_SP_VALUE)))
+		return;
+	if (punc & KDB_SP_SPACEB)
+		kdb_printf(" ");
+	if (punc & KDB_SP_VALUE)
+		kdb_printf(kdb_machreg_fmt0, addr);
+	if (symtab_p2->sym_name) {
+		if (punc & KDB_SP_VALUE)
+			kdb_printf(" ");
+		if (punc & KDB_SP_PAREN)
+			kdb_printf("(");
+		if (strcmp(symtab_p2->mod_name, "kernel"))
+			kdb_printf("[%s]", symtab_p2->mod_name);
+		kdb_printf("%s", symtab_p2->sym_name);
+		if (addr != symtab_p2->sym_start)
+			kdb_printf("+0x%lx", addr - symtab_p2->sym_start);
+		if (punc & KDB_SP_SYMSIZE)
+			kdb_printf("/0x%lx",
+				   symtab_p2->sym_end - symtab_p2->sym_start);
+		if (punc & KDB_SP_PAREN)
+			kdb_printf(")");
+	}
+	if (punc & KDB_SP_SPACEA)
+		kdb_printf(" ");
+	if (punc & KDB_SP_NEWLINE)
+		kdb_printf("\n");
+}
+
+/*
+ * kdb_strdup - kdb equivalent of strdup, for disasm code.
+ * Inputs:
+ *	str	The string to duplicate.
+ *	type	Flags to kmalloc for the new string.
+ * Returns:
+ *	Address of the new string, NULL if storage could not be allocated.
+ * Remarks:
+ *	This is not in lib/string.c because it uses kmalloc which is not
+ *	available when string.o is used in boot loaders.
+ */
+char *kdb_strdup(const char *str, gfp_t type)
+{
+	int n = strlen(str)+1;
+	char *s = kmalloc(n, type);
+	if (!s)
+		return NULL;
+	return strcpy(s, str);
+}
+
+/*
+ * kdb_getarea_size - Read an area of data.  The kdb equivalent of
+ *	copy_from_user, with kdb messages for invalid addresses.
+ * Inputs:
+ *	res	Pointer to the area to receive the result.
+ *	addr	Address of the area to copy.
+ *	size	Size of the area.
+ * Returns:
+ *	0 for success, < 0 for error.
+ */
+int kdb_getarea_size(void *res, unsigned long addr, size_t size)
+{
+	int ret = copy_from_kernel_nofault((char *)res, (char *)addr, size);
+	if (ret) {
+		if (!KDB_STATE(SUPPRESS)) {
+			kdb_func_printf("Bad address 0x%lx\n", addr);
+			KDB_STATE_SET(SUPPRESS);
+		}
+		ret = KDB_BADADDR;
+	} else {
+		KDB_STATE_CLEAR(SUPPRESS);
+	}
+	return ret;
+}
+
+/*
+ * kdb_putarea_size - Write an area of data.  The kdb equivalent of
+ *	copy_to_user, with kdb messages for invalid addresses.
+ * Inputs:
+ *	addr	Address of the area to write to.
+ *	res	Pointer to the area holding the data.
+ *	size	Size of the area.
+ * Returns:
+ *	0 for success, < 0 for error.
+ */
+int kdb_putarea_size(unsigned long addr, void *res, size_t size)
+{
+	int ret = copy_to_kernel_nofault((char *)addr, (char *)res, size);
+	if (ret) {
+		if (!KDB_STATE(SUPPRESS)) {
+			kdb_func_printf("Bad address 0x%lx\n", addr);
+			KDB_STATE_SET(SUPPRESS);
+		}
+		ret = KDB_BADADDR;
+	} else {
+		KDB_STATE_CLEAR(SUPPRESS);
+	}
+	return ret;
+}
+
+/*
+ * kdb_getphys - Read data from a physical address. Validate the
+ * 	address is in range, use kmap_atomic() to get data
+ * 	similar to kdb_getarea() - but for phys addresses
+ * Inputs:
+ * 	res	Pointer to the word to receive the result
+ * 	addr	Physical address of the area to copy
+ * 	size	Size of the area
+ * Returns:
+ *	0 for success, < 0 for error.
+ */
+static int kdb_getphys(void *res, unsigned long addr, size_t size)
+{
+	unsigned long pfn;
+	void *vaddr;
+	struct page *page;
+
+	pfn = (addr >> PAGE_SHIFT);
+	if (!pfn_valid(pfn))
+		return 1;
+	page = pfn_to_page(pfn);
+	vaddr = kmap_atomic(page);
+	memcpy(res, vaddr + (addr & (PAGE_SIZE - 1)), size);
+	kunmap_atomic(vaddr);
+
+	return 0;
+}
+
+/*
+ * kdb_getphysword
+ * Inputs:
+ *	word	Pointer to the word to receive the result.
+ *	addr	Address of the area to copy.
+ *	size	Size of the area.
+ * Returns:
+ *	0 for success, < 0 for error.
+ */
+int kdb_getphysword(unsigned long *word, unsigned long addr, size_t size)
+{
+	int diag;
+	__u8  w1;
+	__u16 w2;
+	__u32 w4;
+	__u64 w8;
+	*word = 0;	/* Default value if addr or size is invalid */
+
+	switch (size) {
+	case 1:
+		diag = kdb_getphys(&w1, addr, sizeof(w1));
+		if (!diag)
+			*word = w1;
+		break;
+	case 2:
+		diag = kdb_getphys(&w2, addr, sizeof(w2));
+		if (!diag)
+			*word = w2;
+		break;
+	case 4:
+		diag = kdb_getphys(&w4, addr, sizeof(w4));
+		if (!diag)
+			*word = w4;
+		break;
+	case 8:
+		if (size <= sizeof(*word)) {
+			diag = kdb_getphys(&w8, addr, sizeof(w8));
+			if (!diag)
+				*word = w8;
+			break;
+		}
+		fallthrough;
+	default:
+		diag = KDB_BADWIDTH;
+		kdb_func_printf("bad width %zu\n", size);
+	}
+	return diag;
+}
+
+/*
+ * kdb_getword - Read a binary value.  Unlike kdb_getarea, this treats
+ *	data as numbers.
+ * Inputs:
+ *	word	Pointer to the word to receive the result.
+ *	addr	Address of the area to copy.
+ *	size	Size of the area.
+ * Returns:
+ *	0 for success, < 0 for error.
+ */
+int kdb_getword(unsigned long *word, unsigned long addr, size_t size)
+{
+	int diag;
+	__u8  w1;
+	__u16 w2;
+	__u32 w4;
+	__u64 w8;
+	*word = 0;	/* Default value if addr or size is invalid */
+	switch (size) {
+	case 1:
+		diag = kdb_getarea(w1, addr);
+		if (!diag)
+			*word = w1;
+		break;
+	case 2:
+		diag = kdb_getarea(w2, addr);
+		if (!diag)
+			*word = w2;
+		break;
+	case 4:
+		diag = kdb_getarea(w4, addr);
+		if (!diag)
+			*word = w4;
+		break;
+	case 8:
+		if (size <= sizeof(*word)) {
+			diag = kdb_getarea(w8, addr);
+			if (!diag)
+				*word = w8;
+			break;
+		}
+		fallthrough;
+	default:
+		diag = KDB_BADWIDTH;
+		kdb_func_printf("bad width %zu\n", size);
+	}
+	return diag;
+}
+
+/*
+ * kdb_putword - Write a binary value.  Unlike kdb_putarea, this
+ *	treats data as numbers.
+ * Inputs:
+ *	addr	Address of the area to write to..
+ *	word	The value to set.
+ *	size	Size of the area.
+ * Returns:
+ *	0 for success, < 0 for error.
+ */
+int kdb_putword(unsigned long addr, unsigned long word, size_t size)
+{
+	int diag;
+	__u8  w1;
+	__u16 w2;
+	__u32 w4;
+	__u64 w8;
+	switch (size) {
+	case 1:
+		w1 = word;
+		diag = kdb_putarea(addr, w1);
+		break;
+	case 2:
+		w2 = word;
+		diag = kdb_putarea(addr, w2);
+		break;
+	case 4:
+		w4 = word;
+		diag = kdb_putarea(addr, w4);
+		break;
+	case 8:
+		if (size <= sizeof(word)) {
+			w8 = word;
+			diag = kdb_putarea(addr, w8);
+			break;
+		}
+		fallthrough;
+	default:
+		diag = KDB_BADWIDTH;
+		kdb_func_printf("bad width %zu\n", size);
+	}
+	return diag;
+}
+
+
+
+/*
+ * kdb_task_state_char - Return the character that represents the task state.
+ * Inputs:
+ *	p	struct task for the process
+ * Returns:
+ *	One character to represent the task state.
+ */
+char kdb_task_state_char (const struct task_struct *p)
+{
+	unsigned long tmp;
+	char state;
+	int cpu;
+
+	if (!p ||
+	    copy_from_kernel_nofault(&tmp, (char *)p, sizeof(unsigned long)))
+		return 'E';
+
+	state = task_state_to_char((struct task_struct *) p);
+
+	if (is_idle_task(p)) {
+		/* Idle task.  Is it really idle, apart from the kdb
+		 * interrupt? */
+		cpu = kdb_process_cpu(p);
+		if (!kdb_task_has_cpu(p) || kgdb_info[cpu].irq_depth == 1) {
+			if (cpu != kdb_initial_cpu)
+				state = '-';	/* idle task */
+		}
+	} else if (!p->mm && strchr("IMS", state)) {
+		state = tolower(state);		/* sleeping system daemon */
+	}
+	return state;
+}
+
+/*
+ * kdb_task_state - Return true if a process has the desired state
+ *	given by the mask.
+ * Inputs:
+ *	p	struct task for the process
+ *	mask	set of characters used to select processes; both NULL
+ *	        and the empty string mean adopt a default filter, which
+ *	        is to suppress sleeping system daemons and the idle tasks
+ * Returns:
+ *	True if the process matches at least one criteria defined by the mask.
+ */
+bool kdb_task_state(const struct task_struct *p, const char *mask)
+{
+	char state = kdb_task_state_char(p);
+
+	/* If there is no mask, then we will filter code that runs when the
+	 * scheduler is idling and any system daemons that are currently
+	 * sleeping.
+	 */
+	if (!mask || mask[0] == '\0')
+		return !strchr("-ims", state);
+
+	/* A is a special case that matches all states */
+	if (strchr(mask, 'A'))
+		return true;
+
+	return strchr(mask, state);
+}
+
+/* Maintain a small stack of kdb_flags to allow recursion without disturbing
+ * the global kdb state.
+ */
+
+static int kdb_flags_stack[4], kdb_flags_index;
+
+void kdb_save_flags(void)
+{
+	BUG_ON(kdb_flags_index >= ARRAY_SIZE(kdb_flags_stack));
+	kdb_flags_stack[kdb_flags_index++] = kdb_flags;
+}
+
+void kdb_restore_flags(void)
+{
+	BUG_ON(kdb_flags_index <= 0);
+	kdb_flags = kdb_flags_stack[--kdb_flags_index];
+}
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
new file mode 100644
index 000000000..e39cb696c
--- /dev/null
+++ b/kernel/delayacct.c
@@ -0,0 +1,276 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* delayacct.c - per-task delay accounting
+ *
+ * Copyright (C) Shailabh Nagar, IBM Corp. 2006
+ */
+
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/sched/cputime.h>
+#include <linux/sched/clock.h>
+#include <linux/slab.h>
+#include <linux/taskstats.h>
+#include <linux/sysctl.h>
+#include <linux/delayacct.h>
+#include <linux/module.h>
+
+DEFINE_STATIC_KEY_FALSE(delayacct_key);
+int delayacct_on __read_mostly;	/* Delay accounting turned on/off */
+struct kmem_cache *delayacct_cache;
+
+static void set_delayacct(bool enabled)
+{
+	if (enabled) {
+		static_branch_enable(&delayacct_key);
+		delayacct_on = 1;
+	} else {
+		delayacct_on = 0;
+		static_branch_disable(&delayacct_key);
+	}
+}
+
+static int __init delayacct_setup_enable(char *str)
+{
+	delayacct_on = 1;
+	return 1;
+}
+__setup("delayacct", delayacct_setup_enable);
+
+void delayacct_init(void)
+{
+	delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT);
+	delayacct_tsk_init(&init_task);
+	set_delayacct(delayacct_on);
+}
+
+#ifdef CONFIG_PROC_SYSCTL
+static int sysctl_delayacct(struct ctl_table *table, int write, void *buffer,
+		     size_t *lenp, loff_t *ppos)
+{
+	int state = delayacct_on;
+	struct ctl_table t;
+	int err;
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	t = *table;
+	t.data = &state;
+	err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
+	if (err < 0)
+		return err;
+	if (write)
+		set_delayacct(state);
+	return err;
+}
+
+static struct ctl_table kern_delayacct_table[] = {
+	{
+		.procname       = "task_delayacct",
+		.data           = NULL,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sysctl_delayacct,
+		.extra1         = SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE,
+	},
+	{ }
+};
+
+static __init int kernel_delayacct_sysctls_init(void)
+{
+	register_sysctl_init("kernel", kern_delayacct_table);
+	return 0;
+}
+late_initcall(kernel_delayacct_sysctls_init);
+#endif
+
+void __delayacct_tsk_init(struct task_struct *tsk)
+{
+	tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
+	if (tsk->delays)
+		raw_spin_lock_init(&tsk->delays->lock);
+}
+
+/*
+ * Finish delay accounting for a statistic using its timestamps (@start),
+ * accumalator (@total) and @count
+ */
+static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, u32 *count)
+{
+	s64 ns = local_clock() - *start;
+	unsigned long flags;
+
+	if (ns > 0) {
+		raw_spin_lock_irqsave(lock, flags);
+		*total += ns;
+		(*count)++;
+		raw_spin_unlock_irqrestore(lock, flags);
+	}
+}
+
+void __delayacct_blkio_start(void)
+{
+	current->delays->blkio_start = local_clock();
+}
+
+/*
+ * We cannot rely on the `current` macro, as we haven't yet switched back to
+ * the process being woken.
+ */
+void __delayacct_blkio_end(struct task_struct *p)
+{
+	delayacct_end(&p->delays->lock,
+		      &p->delays->blkio_start,
+		      &p->delays->blkio_delay,
+		      &p->delays->blkio_count);
+}
+
+int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
+{
+	u64 utime, stime, stimescaled, utimescaled;
+	unsigned long long t2, t3;
+	unsigned long flags, t1;
+	s64 tmp;
+
+	task_cputime(tsk, &utime, &stime);
+	tmp = (s64)d->cpu_run_real_total;
+	tmp += utime + stime;
+	d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
+
+	task_cputime_scaled(tsk, &utimescaled, &stimescaled);
+	tmp = (s64)d->cpu_scaled_run_real_total;
+	tmp += utimescaled + stimescaled;
+	d->cpu_scaled_run_real_total =
+		(tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp;
+
+	/*
+	 * No locking available for sched_info (and too expensive to add one)
+	 * Mitigate by taking snapshot of values
+	 */
+	t1 = tsk->sched_info.pcount;
+	t2 = tsk->sched_info.run_delay;
+	t3 = tsk->se.sum_exec_runtime;
+
+	d->cpu_count += t1;
+
+	tmp = (s64)d->cpu_delay_total + t2;
+	d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
+
+	tmp = (s64)d->cpu_run_virtual_total + t3;
+	d->cpu_run_virtual_total =
+		(tmp < (s64)d->cpu_run_virtual_total) ?	0 : tmp;
+
+	if (!tsk->delays)
+		return 0;
+
+	/* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
+
+	raw_spin_lock_irqsave(&tsk->delays->lock, flags);
+	tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
+	d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
+	tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
+	d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
+	tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
+	d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
+	tmp = d->thrashing_delay_total + tsk->delays->thrashing_delay;
+	d->thrashing_delay_total = (tmp < d->thrashing_delay_total) ? 0 : tmp;
+	tmp = d->compact_delay_total + tsk->delays->compact_delay;
+	d->compact_delay_total = (tmp < d->compact_delay_total) ? 0 : tmp;
+	tmp = d->wpcopy_delay_total + tsk->delays->wpcopy_delay;
+	d->wpcopy_delay_total = (tmp < d->wpcopy_delay_total) ? 0 : tmp;
+	d->blkio_count += tsk->delays->blkio_count;
+	d->swapin_count += tsk->delays->swapin_count;
+	d->freepages_count += tsk->delays->freepages_count;
+	d->thrashing_count += tsk->delays->thrashing_count;
+	d->compact_count += tsk->delays->compact_count;
+	d->wpcopy_count += tsk->delays->wpcopy_count;
+	raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
+
+	return 0;
+}
+
+__u64 __delayacct_blkio_ticks(struct task_struct *tsk)
+{
+	__u64 ret;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&tsk->delays->lock, flags);
+	ret = nsec_to_clock_t(tsk->delays->blkio_delay);
+	raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
+	return ret;
+}
+
+void __delayacct_freepages_start(void)
+{
+	current->delays->freepages_start = local_clock();
+}
+
+void __delayacct_freepages_end(void)
+{
+	delayacct_end(&current->delays->lock,
+		      &current->delays->freepages_start,
+		      &current->delays->freepages_delay,
+		      &current->delays->freepages_count);
+}
+
+void __delayacct_thrashing_start(bool *in_thrashing)
+{
+	*in_thrashing = !!current->in_thrashing;
+	if (*in_thrashing)
+		return;
+
+	current->in_thrashing = 1;
+	current->delays->thrashing_start = local_clock();
+}
+
+void __delayacct_thrashing_end(bool *in_thrashing)
+{
+	if (*in_thrashing)
+		return;
+
+	current->in_thrashing = 0;
+	delayacct_end(&current->delays->lock,
+		      &current->delays->thrashing_start,
+		      &current->delays->thrashing_delay,
+		      &current->delays->thrashing_count);
+}
+
+void __delayacct_swapin_start(void)
+{
+	current->delays->swapin_start = local_clock();
+}
+
+void __delayacct_swapin_end(void)
+{
+	delayacct_end(&current->delays->lock,
+		      &current->delays->swapin_start,
+		      &current->delays->swapin_delay,
+		      &current->delays->swapin_count);
+}
+
+void __delayacct_compact_start(void)
+{
+	current->delays->compact_start = local_clock();
+}
+
+void __delayacct_compact_end(void)
+{
+	delayacct_end(&current->delays->lock,
+		      &current->delays->compact_start,
+		      &current->delays->compact_delay,
+		      &current->delays->compact_count);
+}
+
+void __delayacct_wpcopy_start(void)
+{
+	current->delays->wpcopy_start = local_clock();
+}
+
+void __delayacct_wpcopy_end(void)
+{
+	delayacct_end(&current->delays->lock,
+		      &current->delays->wpcopy_start,
+		      &current->delays->wpcopy_delay,
+		      &current->delays->wpcopy_count);
+}
diff --git a/kernel/dma.c b/kernel/dma.c
new file mode 100644
index 000000000..40f152936
--- /dev/null
+++ b/kernel/dma.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/kernel/dma.c: A DMA channel allocator. Inspired by linux/kernel/irq.c.
+ *
+ * Written by Hennus Bergman, 1992.
+ *
+ * 1994/12/26: Changes by Alex Nash to fix a minor bug in /proc/dma.
+ *   In the previous version the reported device could end up being wrong,
+ *   if a device requested a DMA channel that was already in use.
+ *   [It also happened to remove the sizeof(char *) == sizeof(int)
+ *   assumption introduced because of those /proc/dma patches. -- Hennus]
+ */
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/seq_file.h>
+#include <linux/proc_fs.h>
+#include <linux/init.h>
+#include <asm/dma.h>
+
+
+
+/* A note on resource allocation:
+ *
+ * All drivers needing DMA channels, should allocate and release them
+ * through the public routines `request_dma()' and `free_dma()'.
+ *
+ * In order to avoid problems, all processes should allocate resources in
+ * the same sequence and release them in the reverse order.
+ *
+ * So, when allocating DMAs and IRQs, first allocate the IRQ, then the DMA.
+ * When releasing them, first release the DMA, then release the IRQ.
+ * If you don't, you may cause allocation requests to fail unnecessarily.
+ * This doesn't really matter now, but it will once we get real semaphores
+ * in the kernel.
+ */
+
+
+DEFINE_SPINLOCK(dma_spin_lock);
+
+/*
+ *	If our port doesn't define this it has no PC like DMA
+ */
+
+#ifdef MAX_DMA_CHANNELS
+
+
+/* Channel n is busy iff dma_chan_busy[n].lock != 0.
+ * DMA0 used to be reserved for DRAM refresh, but apparently not any more...
+ * DMA4 is reserved for cascading.
+ */
+
+struct dma_chan {
+	int  lock;
+	const char *device_id;
+};
+
+static struct dma_chan dma_chan_busy[MAX_DMA_CHANNELS] = {
+	[4] = { 1, "cascade" },
+};
+
+
+/**
+ * request_dma - request and reserve a system DMA channel
+ * @dmanr: DMA channel number
+ * @device_id: reserving device ID string, used in /proc/dma
+ */
+int request_dma(unsigned int dmanr, const char * device_id)
+{
+	if (dmanr >= MAX_DMA_CHANNELS)
+		return -EINVAL;
+
+	if (xchg(&dma_chan_busy[dmanr].lock, 1) != 0)
+		return -EBUSY;
+
+	dma_chan_busy[dmanr].device_id = device_id;
+
+	/* old flag was 0, now contains 1 to indicate busy */
+	return 0;
+} /* request_dma */
+
+/**
+ * free_dma - free a reserved system DMA channel
+ * @dmanr: DMA channel number
+ */
+void free_dma(unsigned int dmanr)
+{
+	if (dmanr >= MAX_DMA_CHANNELS) {
+		printk(KERN_WARNING "Trying to free DMA%d\n", dmanr);
+		return;
+	}
+
+	if (xchg(&dma_chan_busy[dmanr].lock, 0) == 0) {
+		printk(KERN_WARNING "Trying to free free DMA%d\n", dmanr);
+		return;
+	}
+
+} /* free_dma */
+
+#else
+
+int request_dma(unsigned int dmanr, const char *device_id)
+{
+	return -EINVAL;
+}
+
+void free_dma(unsigned int dmanr)
+{
+}
+
+#endif
+
+#ifdef CONFIG_PROC_FS
+
+#ifdef MAX_DMA_CHANNELS
+static int proc_dma_show(struct seq_file *m, void *v)
+{
+	int i;
+
+	for (i = 0 ; i < MAX_DMA_CHANNELS ; i++) {
+		if (dma_chan_busy[i].lock) {
+			seq_printf(m, "%2d: %s\n", i,
+				   dma_chan_busy[i].device_id);
+		}
+	}
+	return 0;
+}
+#else
+static int proc_dma_show(struct seq_file *m, void *v)
+{
+	seq_puts(m, "No DMA\n");
+	return 0;
+}
+#endif /* MAX_DMA_CHANNELS */
+
+static int __init proc_dma_init(void)
+{
+	proc_create_single("dma", 0, NULL, proc_dma_show);
+	return 0;
+}
+
+__initcall(proc_dma_init);
+#endif
+
+EXPORT_SYMBOL(request_dma);
+EXPORT_SYMBOL(free_dma);
+EXPORT_SYMBOL(dma_spin_lock);
diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
new file mode 100644
index 000000000..56866aaa2
--- /dev/null
+++ b/kernel/dma/Kconfig
@@ -0,0 +1,244 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config NO_DMA
+	bool
+
+config HAS_DMA
+	bool
+	depends on !NO_DMA
+	default y
+
+config DMA_OPS
+	depends on HAS_DMA
+	bool
+
+#
+# IOMMU drivers that can bypass the IOMMU code and optionally use the direct
+# mapping fast path should select this option and set the dma_ops_bypass
+# flag in struct device where applicable
+#
+config DMA_OPS_BYPASS
+	bool
+
+# Lets platform IOMMU driver choose between bypass and IOMMU
+config ARCH_HAS_DMA_MAP_DIRECT
+	bool
+
+config NEED_SG_DMA_LENGTH
+	bool
+
+config NEED_DMA_MAP_STATE
+	bool
+
+config ARCH_DMA_ADDR_T_64BIT
+	def_bool 64BIT || PHYS_ADDR_T_64BIT
+
+config ARCH_HAS_DMA_SET_MASK
+	bool
+
+#
+# Select this option if the architecture needs special handling for
+# DMA_ATTR_WRITE_COMBINE.  Normally the "uncached" mapping should be what
+# people thing of when saying write combine, so very few platforms should
+# need to enable this.
+#
+config ARCH_HAS_DMA_WRITE_COMBINE
+	bool
+
+#
+# Select if the architectures provides the arch_dma_mark_clean hook
+#
+config ARCH_HAS_DMA_MARK_CLEAN
+	bool
+
+config DMA_DECLARE_COHERENT
+	bool
+
+config ARCH_HAS_SETUP_DMA_OPS
+	bool
+
+config ARCH_HAS_TEARDOWN_DMA_OPS
+	bool
+
+config ARCH_HAS_SYNC_DMA_FOR_DEVICE
+	bool
+
+config ARCH_HAS_SYNC_DMA_FOR_CPU
+	bool
+	select NEED_DMA_MAP_STATE
+
+config ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
+	bool
+
+config ARCH_HAS_DMA_PREP_COHERENT
+	bool
+
+config ARCH_HAS_FORCE_DMA_UNENCRYPTED
+	bool
+
+config SWIOTLB
+	bool
+	select NEED_DMA_MAP_STATE
+
+config DMA_RESTRICTED_POOL
+	bool "DMA Restricted Pool"
+	depends on OF && OF_RESERVED_MEM && SWIOTLB
+	help
+	  This enables support for restricted DMA pools which provide a level of
+	  DMA memory protection on systems with limited hardware protection
+	  capabilities, such as those lacking an IOMMU.
+
+	  For more information see
+	  <Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt>
+	  and <kernel/dma/swiotlb.c>.
+	  If unsure, say "n".
+
+#
+# Should be selected if we can mmap non-coherent mappings to userspace.
+# The only thing that is really required is a way to set an uncached bit
+# in the pagetables
+#
+config DMA_NONCOHERENT_MMAP
+	default y if !MMU
+	bool
+
+config DMA_COHERENT_POOL
+	select GENERIC_ALLOCATOR
+	bool
+
+config DMA_GLOBAL_POOL
+	select DMA_DECLARE_COHERENT
+	bool
+
+config DMA_DIRECT_REMAP
+	bool
+	select DMA_COHERENT_POOL
+	select DMA_NONCOHERENT_MMAP
+
+config DMA_CMA
+	bool "DMA Contiguous Memory Allocator"
+	depends on HAVE_DMA_CONTIGUOUS && CMA
+	help
+	  This enables the Contiguous Memory Allocator which allows drivers
+	  to allocate big physically-contiguous blocks of memory for use with
+	  hardware components that do not support I/O map nor scatter-gather.
+
+	  You can disable CMA by specifying "cma=0" on the kernel's command
+	  line.
+
+	  For more information see <kernel/dma/contiguous.c>.
+	  If unsure, say "n".
+
+if  DMA_CMA
+
+config DMA_PERNUMA_CMA
+	bool "Enable separate DMA Contiguous Memory Area for each NUMA Node"
+	default NUMA && ARM64
+	help
+	  Enable this option to get pernuma CMA areas so that devices like
+	  ARM64 SMMU can get local memory by DMA coherent APIs.
+
+	  You can set the size of pernuma CMA by specifying "cma_pernuma=size"
+	  on the kernel's command line.
+
+comment "Default contiguous memory area size:"
+
+config CMA_SIZE_MBYTES
+	int "Size in Mega Bytes"
+	depends on !CMA_SIZE_SEL_PERCENTAGE
+	default 0 if X86
+	default 16
+	help
+	  Defines the size (in MiB) of the default memory area for Contiguous
+	  Memory Allocator.  If the size of 0 is selected, CMA is disabled by
+	  default, but it can be enabled by passing cma=size[MG] to the kernel.
+
+
+config CMA_SIZE_PERCENTAGE
+	int "Percentage of total memory"
+	depends on !CMA_SIZE_SEL_MBYTES
+	default 0 if X86
+	default 10
+	help
+	  Defines the size of the default memory area for Contiguous Memory
+	  Allocator as a percentage of the total memory in the system.
+	  If 0 percent is selected, CMA is disabled by default, but it can be
+	  enabled by passing cma=size[MG] to the kernel.
+
+choice
+	prompt "Selected region size"
+	default CMA_SIZE_SEL_MBYTES
+
+config CMA_SIZE_SEL_MBYTES
+	bool "Use mega bytes value only"
+
+config CMA_SIZE_SEL_PERCENTAGE
+	bool "Use percentage value only"
+
+config CMA_SIZE_SEL_MIN
+	bool "Use lower value (minimum)"
+
+config CMA_SIZE_SEL_MAX
+	bool "Use higher value (maximum)"
+
+endchoice
+
+config CMA_ALIGNMENT
+	int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
+	range 2 12
+	default 8
+	help
+	  DMA mapping framework by default aligns all buffers to the smallest
+	  PAGE_SIZE order which is greater than or equal to the requested buffer
+	  size. This works well for buffers up to a few hundreds kilobytes, but
+	  for larger buffers it just a memory waste. With this parameter you can
+	  specify the maximum PAGE_SIZE order for contiguous buffers. Larger
+	  buffers will be aligned only to this specified order. The order is
+	  expressed as a power of two multiplied by the PAGE_SIZE.
+
+	  For example, if your system defaults to 4KiB pages, the order value
+	  of 8 means that the buffers will be aligned up to 1MiB only.
+
+	  If unsure, leave the default value "8".
+
+endif
+
+config DMA_API_DEBUG
+	bool "Enable debugging of DMA-API usage"
+	select NEED_DMA_MAP_STATE
+	help
+	  Enable this option to debug the use of the DMA API by device drivers.
+	  With this option you will be able to detect common bugs in device
+	  drivers like double-freeing of DMA mappings or freeing mappings that
+	  were never allocated.
+
+	  This option causes a performance degradation.  Use only if you want to
+	  debug device drivers and dma interactions.
+
+	  If unsure, say N.
+
+config DMA_API_DEBUG_SG
+	bool "Debug DMA scatter-gather usage"
+	default y
+	depends on DMA_API_DEBUG
+	help
+	  Perform extra checking that callers of dma_map_sg() have respected the
+	  appropriate segment length/boundary limits for the given device when
+	  preparing DMA scatterlists.
+
+	  This is particularly likely to have been overlooked in cases where the
+	  dma_map_sg() API is used for general bulk mapping of pages rather than
+	  preparing literal scatter-gather descriptors, where there is a risk of
+	  unexpected behaviour from DMA API implementations if the scatterlist
+	  is technically out-of-spec.
+
+	  If unsure, say N.
+
+config DMA_MAP_BENCHMARK
+	bool "Enable benchmarking of streaming DMA mapping"
+	depends on DEBUG_FS
+	help
+	  Provides /sys/kernel/debug/dma_map_benchmark that helps with testing
+	  performance of dma_(un)map_page.
+
+	  See tools/testing/selftests/dma/dma_map_benchmark.c
diff --git a/kernel/dma/Makefile b/kernel/dma/Makefile
new file mode 100644
index 000000000..21926e46e
--- /dev/null
+++ b/kernel/dma/Makefile
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_HAS_DMA)			+= mapping.o direct.o
+obj-$(CONFIG_DMA_OPS)			+= ops_helpers.o
+obj-$(CONFIG_DMA_OPS)			+= dummy.o
+obj-$(CONFIG_DMA_CMA)			+= contiguous.o
+obj-$(CONFIG_DMA_DECLARE_COHERENT)	+= coherent.o
+obj-$(CONFIG_DMA_API_DEBUG)		+= debug.o
+obj-$(CONFIG_SWIOTLB)			+= swiotlb.o
+obj-$(CONFIG_DMA_COHERENT_POOL)		+= pool.o
+obj-$(CONFIG_MMU)			+= remap.o
+obj-$(CONFIG_DMA_MAP_BENCHMARK)		+= map_benchmark.o
diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
new file mode 100644
index 000000000..ff5683a57
--- /dev/null
+++ b/kernel/dma/coherent.c
@@ -0,0 +1,403 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Coherent per-device memory handling.
+ * Borrowed from i386
+ */
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/dma-direct.h>
+#include <linux/dma-map-ops.h>
+
+struct dma_coherent_mem {
+	void		*virt_base;
+	dma_addr_t	device_base;
+	unsigned long	pfn_base;
+	int		size;
+	unsigned long	*bitmap;
+	spinlock_t	spinlock;
+	bool		use_dev_dma_pfn_offset;
+};
+
+static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)
+{
+	if (dev && dev->dma_mem)
+		return dev->dma_mem;
+	return NULL;
+}
+
+static inline dma_addr_t dma_get_device_base(struct device *dev,
+					     struct dma_coherent_mem * mem)
+{
+	if (mem->use_dev_dma_pfn_offset)
+		return phys_to_dma(dev, PFN_PHYS(mem->pfn_base));
+	return mem->device_base;
+}
+
+static struct dma_coherent_mem *dma_init_coherent_memory(phys_addr_t phys_addr,
+		dma_addr_t device_addr, size_t size, bool use_dma_pfn_offset)
+{
+	struct dma_coherent_mem *dma_mem;
+	int pages = size >> PAGE_SHIFT;
+	void *mem_base;
+
+	if (!size)
+		return ERR_PTR(-EINVAL);
+
+	mem_base = memremap(phys_addr, size, MEMREMAP_WC);
+	if (!mem_base)
+		return ERR_PTR(-EINVAL);
+
+	dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
+	if (!dma_mem)
+		goto out_unmap_membase;
+	dma_mem->bitmap = bitmap_zalloc(pages, GFP_KERNEL);
+	if (!dma_mem->bitmap)
+		goto out_free_dma_mem;
+
+	dma_mem->virt_base = mem_base;
+	dma_mem->device_base = device_addr;
+	dma_mem->pfn_base = PFN_DOWN(phys_addr);
+	dma_mem->size = pages;
+	dma_mem->use_dev_dma_pfn_offset = use_dma_pfn_offset;
+	spin_lock_init(&dma_mem->spinlock);
+
+	return dma_mem;
+
+out_free_dma_mem:
+	kfree(dma_mem);
+out_unmap_membase:
+	memunmap(mem_base);
+	pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %zd MiB\n",
+		&phys_addr, size / SZ_1M);
+	return ERR_PTR(-ENOMEM);
+}
+
+static void _dma_release_coherent_memory(struct dma_coherent_mem *mem)
+{
+	if (!mem)
+		return;
+
+	memunmap(mem->virt_base);
+	bitmap_free(mem->bitmap);
+	kfree(mem);
+}
+
+static int dma_assign_coherent_memory(struct device *dev,
+				      struct dma_coherent_mem *mem)
+{
+	if (!dev)
+		return -ENODEV;
+
+	if (dev->dma_mem)
+		return -EBUSY;
+
+	dev->dma_mem = mem;
+	return 0;
+}
+
+/*
+ * Declare a region of memory to be handed out by dma_alloc_coherent() when it
+ * is asked for coherent memory for this device.  This shall only be used
+ * from platform code, usually based on the device tree description.
+ *
+ * phys_addr is the CPU physical address to which the memory is currently
+ * assigned (this will be ioremapped so the CPU can access the region).
+ *
+ * device_addr is the DMA address the device needs to be programmed with to
+ * actually address this memory (this will be handed out as the dma_addr_t in
+ * dma_alloc_coherent()).
+ *
+ * size is the size of the area (must be a multiple of PAGE_SIZE).
+ *
+ * As a simplification for the platforms, only *one* such region of memory may
+ * be declared per device.
+ */
+int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
+				dma_addr_t device_addr, size_t size)
+{
+	struct dma_coherent_mem *mem;
+	int ret;
+
+	mem = dma_init_coherent_memory(phys_addr, device_addr, size, false);
+	if (IS_ERR(mem))
+		return PTR_ERR(mem);
+
+	ret = dma_assign_coherent_memory(dev, mem);
+	if (ret)
+		_dma_release_coherent_memory(mem);
+	return ret;
+}
+
+void dma_release_coherent_memory(struct device *dev)
+{
+	if (dev) {
+		_dma_release_coherent_memory(dev->dma_mem);
+		dev->dma_mem = NULL;
+	}
+}
+
+static void *__dma_alloc_from_coherent(struct device *dev,
+				       struct dma_coherent_mem *mem,
+				       ssize_t size, dma_addr_t *dma_handle)
+{
+	int order = get_order(size);
+	unsigned long flags;
+	int pageno;
+	void *ret;
+
+	spin_lock_irqsave(&mem->spinlock, flags);
+
+	if (unlikely(size > ((dma_addr_t)mem->size << PAGE_SHIFT)))
+		goto err;
+
+	pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
+	if (unlikely(pageno < 0))
+		goto err;
+
+	/*
+	 * Memory was found in the coherent area.
+	 */
+	*dma_handle = dma_get_device_base(dev, mem) +
+			((dma_addr_t)pageno << PAGE_SHIFT);
+	ret = mem->virt_base + ((dma_addr_t)pageno << PAGE_SHIFT);
+	spin_unlock_irqrestore(&mem->spinlock, flags);
+	memset(ret, 0, size);
+	return ret;
+err:
+	spin_unlock_irqrestore(&mem->spinlock, flags);
+	return NULL;
+}
+
+/**
+ * dma_alloc_from_dev_coherent() - allocate memory from device coherent pool
+ * @dev:	device from which we allocate memory
+ * @size:	size of requested memory area
+ * @dma_handle:	This will be filled with the correct dma handle
+ * @ret:	This pointer will be filled with the virtual address
+ *		to allocated area.
+ *
+ * This function should be only called from per-arch dma_alloc_coherent()
+ * to support allocation from per-device coherent memory pools.
+ *
+ * Returns 0 if dma_alloc_coherent should continue with allocating from
+ * generic memory areas, or !0 if dma_alloc_coherent should return @ret.
+ */
+int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
+		dma_addr_t *dma_handle, void **ret)
+{
+	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
+
+	if (!mem)
+		return 0;
+
+	*ret = __dma_alloc_from_coherent(dev, mem, size, dma_handle);
+	return 1;
+}
+
+static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
+				       int order, void *vaddr)
+{
+	if (mem && vaddr >= mem->virt_base && vaddr <
+		   (mem->virt_base + ((dma_addr_t)mem->size << PAGE_SHIFT))) {
+		int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
+		unsigned long flags;
+
+		spin_lock_irqsave(&mem->spinlock, flags);
+		bitmap_release_region(mem->bitmap, page, order);
+		spin_unlock_irqrestore(&mem->spinlock, flags);
+		return 1;
+	}
+	return 0;
+}
+
+/**
+ * dma_release_from_dev_coherent() - free memory to device coherent memory pool
+ * @dev:	device from which the memory was allocated
+ * @order:	the order of pages allocated
+ * @vaddr:	virtual address of allocated pages
+ *
+ * This checks whether the memory was allocated from the per-device
+ * coherent memory pool and if so, releases that memory.
+ *
+ * Returns 1 if we correctly released the memory, or 0 if the caller should
+ * proceed with releasing memory from generic pools.
+ */
+int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
+{
+	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
+
+	return __dma_release_from_coherent(mem, order, vaddr);
+}
+
+static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
+		struct vm_area_struct *vma, void *vaddr, size_t size, int *ret)
+{
+	if (mem && vaddr >= mem->virt_base && vaddr + size <=
+		   (mem->virt_base + ((dma_addr_t)mem->size << PAGE_SHIFT))) {
+		unsigned long off = vma->vm_pgoff;
+		int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
+		unsigned long user_count = vma_pages(vma);
+		int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+		*ret = -ENXIO;
+		if (off < count && user_count <= count - off) {
+			unsigned long pfn = mem->pfn_base + start + off;
+			*ret = remap_pfn_range(vma, vma->vm_start, pfn,
+					       user_count << PAGE_SHIFT,
+					       vma->vm_page_prot);
+		}
+		return 1;
+	}
+	return 0;
+}
+
+/**
+ * dma_mmap_from_dev_coherent() - mmap memory from the device coherent pool
+ * @dev:	device from which the memory was allocated
+ * @vma:	vm_area for the userspace memory
+ * @vaddr:	cpu address returned by dma_alloc_from_dev_coherent
+ * @size:	size of the memory buffer allocated
+ * @ret:	result from remap_pfn_range()
+ *
+ * This checks whether the memory was allocated from the per-device
+ * coherent memory pool and if so, maps that memory to the provided vma.
+ *
+ * Returns 1 if @vaddr belongs to the device coherent pool and the caller
+ * should return @ret, or 0 if they should proceed with mapping memory from
+ * generic areas.
+ */
+int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
+			   void *vaddr, size_t size, int *ret)
+{
+	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
+
+	return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
+}
+
+#ifdef CONFIG_DMA_GLOBAL_POOL
+static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
+
+void *dma_alloc_from_global_coherent(struct device *dev, ssize_t size,
+				     dma_addr_t *dma_handle)
+{
+	if (!dma_coherent_default_memory)
+		return NULL;
+
+	return __dma_alloc_from_coherent(dev, dma_coherent_default_memory, size,
+					 dma_handle);
+}
+
+int dma_release_from_global_coherent(int order, void *vaddr)
+{
+	if (!dma_coherent_default_memory)
+		return 0;
+
+	return __dma_release_from_coherent(dma_coherent_default_memory, order,
+			vaddr);
+}
+
+int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr,
+				   size_t size, int *ret)
+{
+	if (!dma_coherent_default_memory)
+		return 0;
+
+	return __dma_mmap_from_coherent(dma_coherent_default_memory, vma,
+					vaddr, size, ret);
+}
+
+int dma_init_global_coherent(phys_addr_t phys_addr, size_t size)
+{
+	struct dma_coherent_mem *mem;
+
+	mem = dma_init_coherent_memory(phys_addr, phys_addr, size, true);
+	if (IS_ERR(mem))
+		return PTR_ERR(mem);
+	dma_coherent_default_memory = mem;
+	pr_info("DMA: default coherent area is set\n");
+	return 0;
+}
+#endif /* CONFIG_DMA_GLOBAL_POOL */
+
+/*
+ * Support for reserved memory regions defined in device tree
+ */
+#ifdef CONFIG_OF_RESERVED_MEM
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
+
+#ifdef CONFIG_DMA_GLOBAL_POOL
+static struct reserved_mem *dma_reserved_default_memory __initdata;
+#endif
+
+static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
+{
+	if (!rmem->priv) {
+		struct dma_coherent_mem *mem;
+
+		mem = dma_init_coherent_memory(rmem->base, rmem->base,
+					       rmem->size, true);
+		if (IS_ERR(mem))
+			return PTR_ERR(mem);
+		rmem->priv = mem;
+	}
+	dma_assign_coherent_memory(dev, rmem->priv);
+	return 0;
+}
+
+static void rmem_dma_device_release(struct reserved_mem *rmem,
+				    struct device *dev)
+{
+	if (dev)
+		dev->dma_mem = NULL;
+}
+
+static const struct reserved_mem_ops rmem_dma_ops = {
+	.device_init	= rmem_dma_device_init,
+	.device_release	= rmem_dma_device_release,
+};
+
+static int __init rmem_dma_setup(struct reserved_mem *rmem)
+{
+	unsigned long node = rmem->fdt_node;
+
+	if (of_get_flat_dt_prop(node, "reusable", NULL))
+		return -EINVAL;
+
+#ifdef CONFIG_ARM
+	if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
+		pr_err("Reserved memory: regions without no-map are not yet supported\n");
+		return -EINVAL;
+	}
+#endif
+
+#ifdef CONFIG_DMA_GLOBAL_POOL
+	if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {
+		WARN(dma_reserved_default_memory,
+		     "Reserved memory: region for default DMA coherent area is redefined\n");
+		dma_reserved_default_memory = rmem;
+	}
+#endif
+
+	rmem->ops = &rmem_dma_ops;
+	pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
+		&rmem->base, (unsigned long)rmem->size / SZ_1M);
+	return 0;
+}
+
+#ifdef CONFIG_DMA_GLOBAL_POOL
+static int __init dma_init_reserved_memory(void)
+{
+	if (!dma_reserved_default_memory)
+		return -ENOMEM;
+	return dma_init_global_coherent(dma_reserved_default_memory->base,
+					dma_reserved_default_memory->size);
+}
+core_initcall(dma_init_reserved_memory);
+#endif /* CONFIG_DMA_GLOBAL_POOL */
+
+RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
+#endif
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
new file mode 100644
index 000000000..6ea80ae42
--- /dev/null
+++ b/kernel/dma/contiguous.c
@@ -0,0 +1,442 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Contiguous Memory Allocator for DMA mapping framework
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Written by:
+ *	Marek Szyprowski <m.szyprowski@samsung.com>
+ *	Michal Nazarewicz <mina86@mina86.com>
+ *
+ * Contiguous Memory Allocator
+ *
+ *   The Contiguous Memory Allocator (CMA) makes it possible to
+ *   allocate big contiguous chunks of memory after the system has
+ *   booted.
+ *
+ * Why is it needed?
+ *
+ *   Various devices on embedded systems have no scatter-getter and/or
+ *   IO map support and require contiguous blocks of memory to
+ *   operate.  They include devices such as cameras, hardware video
+ *   coders, etc.
+ *
+ *   Such devices often require big memory buffers (a full HD frame
+ *   is, for instance, more than 2 mega pixels large, i.e. more than 6
+ *   MB of memory), which makes mechanisms such as kmalloc() or
+ *   alloc_page() ineffective.
+ *
+ *   At the same time, a solution where a big memory region is
+ *   reserved for a device is suboptimal since often more memory is
+ *   reserved then strictly required and, moreover, the memory is
+ *   inaccessible to page system even if device drivers don't use it.
+ *
+ *   CMA tries to solve this issue by operating on memory regions
+ *   where only movable pages can be allocated from.  This way, kernel
+ *   can use the memory for pagecache and when device driver requests
+ *   it, allocated pages can be migrated.
+ */
+
+#define pr_fmt(fmt) "cma: " fmt
+
+#ifdef CONFIG_CMA_DEBUG
+#ifndef DEBUG
+#  define DEBUG
+#endif
+#endif
+
+#include <asm/page.h>
+
+#include <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/sizes.h>
+#include <linux/dma-map-ops.h>
+#include <linux/cma.h>
+
+#ifdef CONFIG_CMA_SIZE_MBYTES
+#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
+#else
+#define CMA_SIZE_MBYTES 0
+#endif
+
+struct cma *dma_contiguous_default_area;
+
+/*
+ * Default global CMA area size can be defined in kernel's .config.
+ * This is useful mainly for distro maintainers to create a kernel
+ * that works correctly for most supported systems.
+ * The size can be set in bytes or as a percentage of the total memory
+ * in the system.
+ *
+ * Users, who want to set the size of global CMA area for their system
+ * should use cma= kernel parameter.
+ */
+static const phys_addr_t size_bytes __initconst =
+	(phys_addr_t)CMA_SIZE_MBYTES * SZ_1M;
+static phys_addr_t  size_cmdline __initdata = -1;
+static phys_addr_t base_cmdline __initdata;
+static phys_addr_t limit_cmdline __initdata;
+
+static int __init early_cma(char *p)
+{
+	if (!p) {
+		pr_err("Config string not provided\n");
+		return -EINVAL;
+	}
+
+	size_cmdline = memparse(p, &p);
+	if (*p != '@')
+		return 0;
+	base_cmdline = memparse(p + 1, &p);
+	if (*p != '-') {
+		limit_cmdline = base_cmdline + size_cmdline;
+		return 0;
+	}
+	limit_cmdline = memparse(p + 1, &p);
+
+	return 0;
+}
+early_param("cma", early_cma);
+
+#ifdef CONFIG_DMA_PERNUMA_CMA
+
+static struct cma *dma_contiguous_pernuma_area[MAX_NUMNODES];
+static phys_addr_t pernuma_size_bytes __initdata;
+
+static int __init early_cma_pernuma(char *p)
+{
+	pernuma_size_bytes = memparse(p, &p);
+	return 0;
+}
+early_param("cma_pernuma", early_cma_pernuma);
+#endif
+
+#ifdef CONFIG_CMA_SIZE_PERCENTAGE
+
+static phys_addr_t __init __maybe_unused cma_early_percent_memory(void)
+{
+	unsigned long total_pages = PHYS_PFN(memblock_phys_mem_size());
+
+	return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
+}
+
+#else
+
+static inline __maybe_unused phys_addr_t cma_early_percent_memory(void)
+{
+	return 0;
+}
+
+#endif
+
+#ifdef CONFIG_DMA_PERNUMA_CMA
+void __init dma_pernuma_cma_reserve(void)
+{
+	int nid;
+
+	if (!pernuma_size_bytes)
+		return;
+
+	for_each_online_node(nid) {
+		int ret;
+		char name[CMA_MAX_NAME];
+		struct cma **cma = &dma_contiguous_pernuma_area[nid];
+
+		snprintf(name, sizeof(name), "pernuma%d", nid);
+		ret = cma_declare_contiguous_nid(0, pernuma_size_bytes, 0, 0,
+						 0, false, name, cma, nid);
+		if (ret) {
+			pr_warn("%s: reservation failed: err %d, node %d", __func__,
+				ret, nid);
+			continue;
+		}
+
+		pr_debug("%s: reserved %llu MiB on node %d\n", __func__,
+			(unsigned long long)pernuma_size_bytes / SZ_1M, nid);
+	}
+}
+#endif
+
+/**
+ * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory.
+ */
+void __init dma_contiguous_reserve(phys_addr_t limit)
+{
+	phys_addr_t selected_size = 0;
+	phys_addr_t selected_base = 0;
+	phys_addr_t selected_limit = limit;
+	bool fixed = false;
+
+	pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
+
+	if (size_cmdline != -1) {
+		selected_size = size_cmdline;
+		selected_base = base_cmdline;
+		selected_limit = min_not_zero(limit_cmdline, limit);
+		if (base_cmdline + size_cmdline == limit_cmdline)
+			fixed = true;
+	} else {
+#ifdef CONFIG_CMA_SIZE_SEL_MBYTES
+		selected_size = size_bytes;
+#elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
+		selected_size = cma_early_percent_memory();
+#elif defined(CONFIG_CMA_SIZE_SEL_MIN)
+		selected_size = min(size_bytes, cma_early_percent_memory());
+#elif defined(CONFIG_CMA_SIZE_SEL_MAX)
+		selected_size = max(size_bytes, cma_early_percent_memory());
+#endif
+	}
+
+	if (selected_size && !dma_contiguous_default_area) {
+		pr_debug("%s: reserving %ld MiB for global area\n", __func__,
+			 (unsigned long)selected_size / SZ_1M);
+
+		dma_contiguous_reserve_area(selected_size, selected_base,
+					    selected_limit,
+					    &dma_contiguous_default_area,
+					    fixed);
+	}
+}
+
+void __weak
+dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
+{
+}
+
+/**
+ * dma_contiguous_reserve_area() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas for specific
+ * devices.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
+				       phys_addr_t limit, struct cma **res_cma,
+				       bool fixed)
+{
+	int ret;
+
+	ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed,
+					"reserved", res_cma);
+	if (ret)
+		return ret;
+
+	/* Architecture specific contiguous memory fixup. */
+	dma_contiguous_early_fixup(cma_get_base(*res_cma),
+				cma_get_size(*res_cma));
+
+	return 0;
+}
+
+/**
+ * dma_alloc_from_contiguous() - allocate pages from contiguous area
+ * @dev:   Pointer to device for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
+ * @no_warn: Avoid printing message about failed allocation.
+ *
+ * This function allocates memory buffer for specified device. It uses
+ * device specific contiguous memory area if available or the default
+ * global one. Requires architecture specific dev_get_cma_area() helper
+ * function.
+ */
+struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
+				       unsigned int align, bool no_warn)
+{
+	if (align > CONFIG_CMA_ALIGNMENT)
+		align = CONFIG_CMA_ALIGNMENT;
+
+	return cma_alloc(dev_get_cma_area(dev), count, align, no_warn);
+}
+
+/**
+ * dma_release_from_contiguous() - release allocated pages
+ * @dev:   Pointer to device for which the pages were allocated.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by dma_alloc_from_contiguous().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+				 int count)
+{
+	return cma_release(dev_get_cma_area(dev), pages, count);
+}
+
+static struct page *cma_alloc_aligned(struct cma *cma, size_t size, gfp_t gfp)
+{
+	unsigned int align = min(get_order(size), CONFIG_CMA_ALIGNMENT);
+
+	return cma_alloc(cma, size >> PAGE_SHIFT, align, gfp & __GFP_NOWARN);
+}
+
+/**
+ * dma_alloc_contiguous() - allocate contiguous pages
+ * @dev:   Pointer to device for which the allocation is performed.
+ * @size:  Requested allocation size.
+ * @gfp:   Allocation flags.
+ *
+ * tries to use device specific contiguous memory area if available, or it
+ * tries to use per-numa cma, if the allocation fails, it will fallback to
+ * try default global one.
+ *
+ * Note that it bypass one-page size of allocations from the per-numa and
+ * global area as the addresses within one page are always contiguous, so
+ * there is no need to waste CMA pages for that kind; it also helps reduce
+ * fragmentations.
+ */
+struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
+{
+#ifdef CONFIG_DMA_PERNUMA_CMA
+	int nid = dev_to_node(dev);
+#endif
+
+	/* CMA can be used only in the context which permits sleeping */
+	if (!gfpflags_allow_blocking(gfp))
+		return NULL;
+	if (dev->cma_area)
+		return cma_alloc_aligned(dev->cma_area, size, gfp);
+	if (size <= PAGE_SIZE)
+		return NULL;
+
+#ifdef CONFIG_DMA_PERNUMA_CMA
+	if (nid != NUMA_NO_NODE && !(gfp & (GFP_DMA | GFP_DMA32))) {
+		struct cma *cma = dma_contiguous_pernuma_area[nid];
+		struct page *page;
+
+		if (cma) {
+			page = cma_alloc_aligned(cma, size, gfp);
+			if (page)
+				return page;
+		}
+	}
+#endif
+	if (!dma_contiguous_default_area)
+		return NULL;
+
+	return cma_alloc_aligned(dma_contiguous_default_area, size, gfp);
+}
+
+/**
+ * dma_free_contiguous() - release allocated pages
+ * @dev:   Pointer to device for which the pages were allocated.
+ * @page:  Pointer to the allocated pages.
+ * @size:  Size of allocated pages.
+ *
+ * This function releases memory allocated by dma_alloc_contiguous(). As the
+ * cma_release returns false when provided pages do not belong to contiguous
+ * area and true otherwise, this function then does a fallback __free_pages()
+ * upon a false-return.
+ */
+void dma_free_contiguous(struct device *dev, struct page *page, size_t size)
+{
+	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+	/* if dev has its own cma, free page from there */
+	if (dev->cma_area) {
+		if (cma_release(dev->cma_area, page, count))
+			return;
+	} else {
+		/*
+		 * otherwise, page is from either per-numa cma or default cma
+		 */
+#ifdef CONFIG_DMA_PERNUMA_CMA
+		if (cma_release(dma_contiguous_pernuma_area[page_to_nid(page)],
+					page, count))
+			return;
+#endif
+		if (cma_release(dma_contiguous_default_area, page, count))
+			return;
+	}
+
+	/* not in any cma, free from buddy */
+	__free_pages(page, get_order(size));
+}
+
+/*
+ * Support for reserved memory regions defined in device tree
+ */
+#ifdef CONFIG_OF_RESERVED_MEM
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
+
+#undef pr_fmt
+#define pr_fmt(fmt) fmt
+
+static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev)
+{
+	dev->cma_area = rmem->priv;
+	return 0;
+}
+
+static void rmem_cma_device_release(struct reserved_mem *rmem,
+				    struct device *dev)
+{
+	dev->cma_area = NULL;
+}
+
+static const struct reserved_mem_ops rmem_cma_ops = {
+	.device_init	= rmem_cma_device_init,
+	.device_release = rmem_cma_device_release,
+};
+
+static int __init rmem_cma_setup(struct reserved_mem *rmem)
+{
+	unsigned long node = rmem->fdt_node;
+	bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
+	struct cma *cma;
+	int err;
+
+	if (size_cmdline != -1 && default_cma) {
+		pr_info("Reserved memory: bypass %s node, using cmdline CMA params instead\n",
+			rmem->name);
+		return -EBUSY;
+	}
+
+	if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
+	    of_get_flat_dt_prop(node, "no-map", NULL))
+		return -EINVAL;
+
+	if (!IS_ALIGNED(rmem->base | rmem->size, CMA_MIN_ALIGNMENT_BYTES)) {
+		pr_err("Reserved memory: incorrect alignment of CMA region\n");
+		return -EINVAL;
+	}
+
+	err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma);
+	if (err) {
+		pr_err("Reserved memory: unable to setup CMA region\n");
+		return err;
+	}
+	/* Architecture specific contiguous memory fixup. */
+	dma_contiguous_early_fixup(rmem->base, rmem->size);
+
+	if (default_cma)
+		dma_contiguous_default_area = cma;
+
+	rmem->ops = &rmem_cma_ops;
+	rmem->priv = cma;
+
+	pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
+		&rmem->base, (unsigned long)rmem->size / SZ_1M);
+
+	return 0;
+}
+RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);
+#endif
diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
new file mode 100644
index 000000000..3ff7089d1
--- /dev/null
+++ b/kernel/dma/debug.c
@@ -0,0 +1,1601 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * Author: Joerg Roedel <joerg.roedel@amd.com>
+ */
+
+#define pr_fmt(fmt)	"DMA-API: " fmt
+
+#include <linux/sched/task_stack.h>
+#include <linux/scatterlist.h>
+#include <linux/dma-map-ops.h>
+#include <linux/sched/task.h>
+#include <linux/stacktrace.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/export.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/ctype.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <asm/sections.h>
+#include "debug.h"
+
+#define HASH_SIZE       16384ULL
+#define HASH_FN_SHIFT   13
+#define HASH_FN_MASK    (HASH_SIZE - 1)
+
+#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
+/* If the pool runs out, add this many new entries at once */
+#define DMA_DEBUG_DYNAMIC_ENTRIES (PAGE_SIZE / sizeof(struct dma_debug_entry))
+
+enum {
+	dma_debug_single,
+	dma_debug_sg,
+	dma_debug_coherent,
+	dma_debug_resource,
+};
+
+enum map_err_types {
+	MAP_ERR_CHECK_NOT_APPLICABLE,
+	MAP_ERR_NOT_CHECKED,
+	MAP_ERR_CHECKED,
+};
+
+#define DMA_DEBUG_STACKTRACE_ENTRIES 5
+
+/**
+ * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
+ * @list: node on pre-allocated free_entries list
+ * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
+ * @size: length of the mapping
+ * @type: single, page, sg, coherent
+ * @direction: enum dma_data_direction
+ * @sg_call_ents: 'nents' from dma_map_sg
+ * @sg_mapped_ents: 'mapped_ents' from dma_map_sg
+ * @pfn: page frame of the start address
+ * @offset: offset of mapping relative to pfn
+ * @map_err_type: track whether dma_mapping_error() was checked
+ * @stacktrace: support backtraces when a violation is detected
+ */
+struct dma_debug_entry {
+	struct list_head list;
+	struct device    *dev;
+	u64              dev_addr;
+	u64              size;
+	int              type;
+	int              direction;
+	int		 sg_call_ents;
+	int		 sg_mapped_ents;
+	unsigned long	 pfn;
+	size_t		 offset;
+	enum map_err_types  map_err_type;
+#ifdef CONFIG_STACKTRACE
+	unsigned int	stack_len;
+	unsigned long	stack_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
+#endif
+} ____cacheline_aligned_in_smp;
+
+typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
+
+struct hash_bucket {
+	struct list_head list;
+	spinlock_t lock;
+};
+
+/* Hash list to save the allocated dma addresses */
+static struct hash_bucket dma_entry_hash[HASH_SIZE];
+/* List of pre-allocated dma_debug_entry's */
+static LIST_HEAD(free_entries);
+/* Lock for the list above */
+static DEFINE_SPINLOCK(free_entries_lock);
+
+/* Global disable flag - will be set in case of an error */
+static bool global_disable __read_mostly;
+
+/* Early initialization disable flag, set at the end of dma_debug_init */
+static bool dma_debug_initialized __read_mostly;
+
+static inline bool dma_debug_disabled(void)
+{
+	return global_disable || !dma_debug_initialized;
+}
+
+/* Global error count */
+static u32 error_count;
+
+/* Global error show enable*/
+static u32 show_all_errors __read_mostly;
+/* Number of errors to show */
+static u32 show_num_errors = 1;
+
+static u32 num_free_entries;
+static u32 min_free_entries;
+static u32 nr_total_entries;
+
+/* number of preallocated entries requested by kernel cmdline */
+static u32 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
+
+/* per-driver filter related state */
+
+#define NAME_MAX_LEN	64
+
+static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
+static struct device_driver *current_driver                    __read_mostly;
+
+static DEFINE_RWLOCK(driver_name_lock);
+
+static const char *const maperr2str[] = {
+	[MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
+	[MAP_ERR_NOT_CHECKED] = "dma map error not checked",
+	[MAP_ERR_CHECKED] = "dma map error checked",
+};
+
+static const char *type2name[] = {
+	[dma_debug_single] = "single",
+	[dma_debug_sg] = "scather-gather",
+	[dma_debug_coherent] = "coherent",
+	[dma_debug_resource] = "resource",
+};
+
+static const char *dir2name[] = {
+	[DMA_BIDIRECTIONAL]	= "DMA_BIDIRECTIONAL",
+	[DMA_TO_DEVICE]		= "DMA_TO_DEVICE",
+	[DMA_FROM_DEVICE]	= "DMA_FROM_DEVICE",
+	[DMA_NONE]		= "DMA_NONE",
+};
+
+/*
+ * The access to some variables in this macro is racy. We can't use atomic_t
+ * here because all these variables are exported to debugfs. Some of them even
+ * writeable. This is also the reason why a lock won't help much. But anyway,
+ * the races are no big deal. Here is why:
+ *
+ *   error_count: the addition is racy, but the worst thing that can happen is
+ *                that we don't count some errors
+ *   show_num_errors: the subtraction is racy. Also no big deal because in
+ *                    worst case this will result in one warning more in the
+ *                    system log than the user configured. This variable is
+ *                    writeable via debugfs.
+ */
+static inline void dump_entry_trace(struct dma_debug_entry *entry)
+{
+#ifdef CONFIG_STACKTRACE
+	if (entry) {
+		pr_warn("Mapped at:\n");
+		stack_trace_print(entry->stack_entries, entry->stack_len, 0);
+	}
+#endif
+}
+
+static bool driver_filter(struct device *dev)
+{
+	struct device_driver *drv;
+	unsigned long flags;
+	bool ret;
+
+	/* driver filter off */
+	if (likely(!current_driver_name[0]))
+		return true;
+
+	/* driver filter on and initialized */
+	if (current_driver && dev && dev->driver == current_driver)
+		return true;
+
+	/* driver filter on, but we can't filter on a NULL device... */
+	if (!dev)
+		return false;
+
+	if (current_driver || !current_driver_name[0])
+		return false;
+
+	/* driver filter on but not yet initialized */
+	drv = dev->driver;
+	if (!drv)
+		return false;
+
+	/* lock to protect against change of current_driver_name */
+	read_lock_irqsave(&driver_name_lock, flags);
+
+	ret = false;
+	if (drv->name &&
+	    strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
+		current_driver = drv;
+		ret = true;
+	}
+
+	read_unlock_irqrestore(&driver_name_lock, flags);
+
+	return ret;
+}
+
+#define err_printk(dev, entry, format, arg...) do {			\
+		error_count += 1;					\
+		if (driver_filter(dev) &&				\
+		    (show_all_errors || show_num_errors > 0)) {		\
+			WARN(1, pr_fmt("%s %s: ") format,		\
+			     dev ? dev_driver_string(dev) : "NULL",	\
+			     dev ? dev_name(dev) : "NULL", ## arg);	\
+			dump_entry_trace(entry);			\
+		}							\
+		if (!show_all_errors && show_num_errors > 0)		\
+			show_num_errors -= 1;				\
+	} while (0);
+
+/*
+ * Hash related functions
+ *
+ * Every DMA-API request is saved into a struct dma_debug_entry. To
+ * have quick access to these structs they are stored into a hash.
+ */
+static int hash_fn(struct dma_debug_entry *entry)
+{
+	/*
+	 * Hash function is based on the dma address.
+	 * We use bits 20-27 here as the index into the hash
+	 */
+	return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
+}
+
+/*
+ * Request exclusive access to a hash bucket for a given dma_debug_entry.
+ */
+static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
+					   unsigned long *flags)
+	__acquires(&dma_entry_hash[idx].lock)
+{
+	int idx = hash_fn(entry);
+	unsigned long __flags;
+
+	spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
+	*flags = __flags;
+	return &dma_entry_hash[idx];
+}
+
+/*
+ * Give up exclusive access to the hash bucket
+ */
+static void put_hash_bucket(struct hash_bucket *bucket,
+			    unsigned long flags)
+	__releases(&bucket->lock)
+{
+	spin_unlock_irqrestore(&bucket->lock, flags);
+}
+
+static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
+{
+	return ((a->dev_addr == b->dev_addr) &&
+		(a->dev == b->dev)) ? true : false;
+}
+
+static bool containing_match(struct dma_debug_entry *a,
+			     struct dma_debug_entry *b)
+{
+	if (a->dev != b->dev)
+		return false;
+
+	if ((b->dev_addr <= a->dev_addr) &&
+	    ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
+		return true;
+
+	return false;
+}
+
+/*
+ * Search a given entry in the hash bucket list
+ */
+static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
+						  struct dma_debug_entry *ref,
+						  match_fn match)
+{
+	struct dma_debug_entry *entry, *ret = NULL;
+	int matches = 0, match_lvl, last_lvl = -1;
+
+	list_for_each_entry(entry, &bucket->list, list) {
+		if (!match(ref, entry))
+			continue;
+
+		/*
+		 * Some drivers map the same physical address multiple
+		 * times. Without a hardware IOMMU this results in the
+		 * same device addresses being put into the dma-debug
+		 * hash multiple times too. This can result in false
+		 * positives being reported. Therefore we implement a
+		 * best-fit algorithm here which returns the entry from
+		 * the hash which fits best to the reference value
+		 * instead of the first-fit.
+		 */
+		matches += 1;
+		match_lvl = 0;
+		entry->size         == ref->size         ? ++match_lvl : 0;
+		entry->type         == ref->type         ? ++match_lvl : 0;
+		entry->direction    == ref->direction    ? ++match_lvl : 0;
+		entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
+
+		if (match_lvl == 4) {
+			/* perfect-fit - return the result */
+			return entry;
+		} else if (match_lvl > last_lvl) {
+			/*
+			 * We found an entry that fits better then the
+			 * previous one or it is the 1st match.
+			 */
+			last_lvl = match_lvl;
+			ret      = entry;
+		}
+	}
+
+	/*
+	 * If we have multiple matches but no perfect-fit, just return
+	 * NULL.
+	 */
+	ret = (matches == 1) ? ret : NULL;
+
+	return ret;
+}
+
+static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
+						 struct dma_debug_entry *ref)
+{
+	return __hash_bucket_find(bucket, ref, exact_match);
+}
+
+static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
+						   struct dma_debug_entry *ref,
+						   unsigned long *flags)
+{
+
+	struct dma_debug_entry *entry, index = *ref;
+	int limit = min(HASH_SIZE, (index.dev_addr >> HASH_FN_SHIFT) + 1);
+
+	for (int i = 0; i < limit; i++) {
+		entry = __hash_bucket_find(*bucket, ref, containing_match);
+
+		if (entry)
+			return entry;
+
+		/*
+		 * Nothing found, go back a hash bucket
+		 */
+		put_hash_bucket(*bucket, *flags);
+		index.dev_addr -= (1 << HASH_FN_SHIFT);
+		*bucket = get_hash_bucket(&index, flags);
+	}
+
+	return NULL;
+}
+
+/*
+ * Add an entry to a hash bucket
+ */
+static void hash_bucket_add(struct hash_bucket *bucket,
+			    struct dma_debug_entry *entry)
+{
+	list_add_tail(&entry->list, &bucket->list);
+}
+
+/*
+ * Remove entry from a hash bucket list
+ */
+static void hash_bucket_del(struct dma_debug_entry *entry)
+{
+	list_del(&entry->list);
+}
+
+static unsigned long long phys_addr(struct dma_debug_entry *entry)
+{
+	if (entry->type == dma_debug_resource)
+		return __pfn_to_phys(entry->pfn) + entry->offset;
+
+	return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
+}
+
+/*
+ * Dump mapping entries for debugging purposes
+ */
+void debug_dma_dump_mappings(struct device *dev)
+{
+	int idx;
+
+	for (idx = 0; idx < HASH_SIZE; idx++) {
+		struct hash_bucket *bucket = &dma_entry_hash[idx];
+		struct dma_debug_entry *entry;
+		unsigned long flags;
+
+		spin_lock_irqsave(&bucket->lock, flags);
+
+		list_for_each_entry(entry, &bucket->list, list) {
+			if (!dev || dev == entry->dev) {
+				dev_info(entry->dev,
+					 "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
+					 type2name[entry->type], idx,
+					 phys_addr(entry), entry->pfn,
+					 entry->dev_addr, entry->size,
+					 dir2name[entry->direction],
+					 maperr2str[entry->map_err_type]);
+			}
+		}
+
+		spin_unlock_irqrestore(&bucket->lock, flags);
+		cond_resched();
+	}
+}
+
+/*
+ * For each mapping (initial cacheline in the case of
+ * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
+ * scatterlist, or the cacheline specified in dma_map_single) insert
+ * into this tree using the cacheline as the key. At
+ * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
+ * the entry already exists at insertion time add a tag as a reference
+ * count for the overlapping mappings.  For now, the overlap tracking
+ * just ensures that 'unmaps' balance 'maps' before marking the
+ * cacheline idle, but we should also be flagging overlaps as an API
+ * violation.
+ *
+ * Memory usage is mostly constrained by the maximum number of available
+ * dma-debug entries in that we need a free dma_debug_entry before
+ * inserting into the tree.  In the case of dma_map_page and
+ * dma_alloc_coherent there is only one dma_debug_entry and one
+ * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
+ * other hand, consumes a single dma_debug_entry, but inserts 'nents'
+ * entries into the tree.
+ */
+static RADIX_TREE(dma_active_cacheline, GFP_ATOMIC);
+static DEFINE_SPINLOCK(radix_lock);
+#define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
+#define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
+#define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
+
+static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
+{
+	return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
+		(entry->offset >> L1_CACHE_SHIFT);
+}
+
+static int active_cacheline_read_overlap(phys_addr_t cln)
+{
+	int overlap = 0, i;
+
+	for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
+		if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
+			overlap |= 1 << i;
+	return overlap;
+}
+
+static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
+{
+	int i;
+
+	if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
+		return overlap;
+
+	for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
+		if (overlap & 1 << i)
+			radix_tree_tag_set(&dma_active_cacheline, cln, i);
+		else
+			radix_tree_tag_clear(&dma_active_cacheline, cln, i);
+
+	return overlap;
+}
+
+static void active_cacheline_inc_overlap(phys_addr_t cln)
+{
+	int overlap = active_cacheline_read_overlap(cln);
+
+	overlap = active_cacheline_set_overlap(cln, ++overlap);
+
+	/* If we overflowed the overlap counter then we're potentially
+	 * leaking dma-mappings.
+	 */
+	WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
+		  pr_fmt("exceeded %d overlapping mappings of cacheline %pa\n"),
+		  ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
+}
+
+static int active_cacheline_dec_overlap(phys_addr_t cln)
+{
+	int overlap = active_cacheline_read_overlap(cln);
+
+	return active_cacheline_set_overlap(cln, --overlap);
+}
+
+static int active_cacheline_insert(struct dma_debug_entry *entry)
+{
+	phys_addr_t cln = to_cacheline_number(entry);
+	unsigned long flags;
+	int rc;
+
+	/* If the device is not writing memory then we don't have any
+	 * concerns about the cpu consuming stale data.  This mitigates
+	 * legitimate usages of overlapping mappings.
+	 */
+	if (entry->direction == DMA_TO_DEVICE)
+		return 0;
+
+	spin_lock_irqsave(&radix_lock, flags);
+	rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
+	if (rc == -EEXIST)
+		active_cacheline_inc_overlap(cln);
+	spin_unlock_irqrestore(&radix_lock, flags);
+
+	return rc;
+}
+
+static void active_cacheline_remove(struct dma_debug_entry *entry)
+{
+	phys_addr_t cln = to_cacheline_number(entry);
+	unsigned long flags;
+
+	/* ...mirror the insert case */
+	if (entry->direction == DMA_TO_DEVICE)
+		return;
+
+	spin_lock_irqsave(&radix_lock, flags);
+	/* since we are counting overlaps the final put of the
+	 * cacheline will occur when the overlap count is 0.
+	 * active_cacheline_dec_overlap() returns -1 in that case
+	 */
+	if (active_cacheline_dec_overlap(cln) < 0)
+		radix_tree_delete(&dma_active_cacheline, cln);
+	spin_unlock_irqrestore(&radix_lock, flags);
+}
+
+/*
+ * Wrapper function for adding an entry to the hash.
+ * This function takes care of locking itself.
+ */
+static void add_dma_entry(struct dma_debug_entry *entry, unsigned long attrs)
+{
+	struct hash_bucket *bucket;
+	unsigned long flags;
+	int rc;
+
+	bucket = get_hash_bucket(entry, &flags);
+	hash_bucket_add(bucket, entry);
+	put_hash_bucket(bucket, flags);
+
+	rc = active_cacheline_insert(entry);
+	if (rc == -ENOMEM) {
+		pr_err_once("cacheline tracking ENOMEM, dma-debug disabled\n");
+		global_disable = true;
+	} else if (rc == -EEXIST && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
+		err_printk(entry->dev, entry,
+			"cacheline tracking EEXIST, overlapping mappings aren't supported\n");
+	}
+}
+
+static int dma_debug_create_entries(gfp_t gfp)
+{
+	struct dma_debug_entry *entry;
+	int i;
+
+	entry = (void *)get_zeroed_page(gfp);
+	if (!entry)
+		return -ENOMEM;
+
+	for (i = 0; i < DMA_DEBUG_DYNAMIC_ENTRIES; i++)
+		list_add_tail(&entry[i].list, &free_entries);
+
+	num_free_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
+	nr_total_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
+
+	return 0;
+}
+
+static struct dma_debug_entry *__dma_entry_alloc(void)
+{
+	struct dma_debug_entry *entry;
+
+	entry = list_entry(free_entries.next, struct dma_debug_entry, list);
+	list_del(&entry->list);
+	memset(entry, 0, sizeof(*entry));
+
+	num_free_entries -= 1;
+	if (num_free_entries < min_free_entries)
+		min_free_entries = num_free_entries;
+
+	return entry;
+}
+
+/*
+ * This should be called outside of free_entries_lock scope to avoid potential
+ * deadlocks with serial consoles that use DMA.
+ */
+static void __dma_entry_alloc_check_leak(u32 nr_entries)
+{
+	u32 tmp = nr_entries % nr_prealloc_entries;
+
+	/* Shout each time we tick over some multiple of the initial pool */
+	if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) {
+		pr_info("dma_debug_entry pool grown to %u (%u00%%)\n",
+			nr_entries,
+			(nr_entries / nr_prealloc_entries));
+	}
+}
+
+/* struct dma_entry allocator
+ *
+ * The next two functions implement the allocator for
+ * struct dma_debug_entries.
+ */
+static struct dma_debug_entry *dma_entry_alloc(void)
+{
+	bool alloc_check_leak = false;
+	struct dma_debug_entry *entry;
+	unsigned long flags;
+	u32 nr_entries;
+
+	spin_lock_irqsave(&free_entries_lock, flags);
+	if (num_free_entries == 0) {
+		if (dma_debug_create_entries(GFP_ATOMIC)) {
+			global_disable = true;
+			spin_unlock_irqrestore(&free_entries_lock, flags);
+			pr_err("debugging out of memory - disabling\n");
+			return NULL;
+		}
+		alloc_check_leak = true;
+		nr_entries = nr_total_entries;
+	}
+
+	entry = __dma_entry_alloc();
+
+	spin_unlock_irqrestore(&free_entries_lock, flags);
+
+	if (alloc_check_leak)
+		__dma_entry_alloc_check_leak(nr_entries);
+
+#ifdef CONFIG_STACKTRACE
+	entry->stack_len = stack_trace_save(entry->stack_entries,
+					    ARRAY_SIZE(entry->stack_entries),
+					    1);
+#endif
+	return entry;
+}
+
+static void dma_entry_free(struct dma_debug_entry *entry)
+{
+	unsigned long flags;
+
+	active_cacheline_remove(entry);
+
+	/*
+	 * add to beginning of the list - this way the entries are
+	 * more likely cache hot when they are reallocated.
+	 */
+	spin_lock_irqsave(&free_entries_lock, flags);
+	list_add(&entry->list, &free_entries);
+	num_free_entries += 1;
+	spin_unlock_irqrestore(&free_entries_lock, flags);
+}
+
+/*
+ * DMA-API debugging init code
+ *
+ * The init code does two things:
+ *   1. Initialize core data structures
+ *   2. Preallocate a given number of dma_debug_entry structs
+ */
+
+static ssize_t filter_read(struct file *file, char __user *user_buf,
+			   size_t count, loff_t *ppos)
+{
+	char buf[NAME_MAX_LEN + 1];
+	unsigned long flags;
+	int len;
+
+	if (!current_driver_name[0])
+		return 0;
+
+	/*
+	 * We can't copy to userspace directly because current_driver_name can
+	 * only be read under the driver_name_lock with irqs disabled. So
+	 * create a temporary copy first.
+	 */
+	read_lock_irqsave(&driver_name_lock, flags);
+	len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
+	read_unlock_irqrestore(&driver_name_lock, flags);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t filter_write(struct file *file, const char __user *userbuf,
+			    size_t count, loff_t *ppos)
+{
+	char buf[NAME_MAX_LEN];
+	unsigned long flags;
+	size_t len;
+	int i;
+
+	/*
+	 * We can't copy from userspace directly. Access to
+	 * current_driver_name is protected with a write_lock with irqs
+	 * disabled. Since copy_from_user can fault and may sleep we
+	 * need to copy to temporary buffer first
+	 */
+	len = min(count, (size_t)(NAME_MAX_LEN - 1));
+	if (copy_from_user(buf, userbuf, len))
+		return -EFAULT;
+
+	buf[len] = 0;
+
+	write_lock_irqsave(&driver_name_lock, flags);
+
+	/*
+	 * Now handle the string we got from userspace very carefully.
+	 * The rules are:
+	 *         - only use the first token we got
+	 *         - token delimiter is everything looking like a space
+	 *           character (' ', '\n', '\t' ...)
+	 *
+	 */
+	if (!isalnum(buf[0])) {
+		/*
+		 * If the first character userspace gave us is not
+		 * alphanumerical then assume the filter should be
+		 * switched off.
+		 */
+		if (current_driver_name[0])
+			pr_info("switching off dma-debug driver filter\n");
+		current_driver_name[0] = 0;
+		current_driver = NULL;
+		goto out_unlock;
+	}
+
+	/*
+	 * Now parse out the first token and use it as the name for the
+	 * driver to filter for.
+	 */
+	for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
+		current_driver_name[i] = buf[i];
+		if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
+			break;
+	}
+	current_driver_name[i] = 0;
+	current_driver = NULL;
+
+	pr_info("enable driver filter for driver [%s]\n",
+		current_driver_name);
+
+out_unlock:
+	write_unlock_irqrestore(&driver_name_lock, flags);
+
+	return count;
+}
+
+static const struct file_operations filter_fops = {
+	.read  = filter_read,
+	.write = filter_write,
+	.llseek = default_llseek,
+};
+
+static int dump_show(struct seq_file *seq, void *v)
+{
+	int idx;
+
+	for (idx = 0; idx < HASH_SIZE; idx++) {
+		struct hash_bucket *bucket = &dma_entry_hash[idx];
+		struct dma_debug_entry *entry;
+		unsigned long flags;
+
+		spin_lock_irqsave(&bucket->lock, flags);
+		list_for_each_entry(entry, &bucket->list, list) {
+			seq_printf(seq,
+				   "%s %s %s idx %d P=%llx N=%lx D=%llx L=%llx %s %s\n",
+				   dev_name(entry->dev),
+				   dev_driver_string(entry->dev),
+				   type2name[entry->type], idx,
+				   phys_addr(entry), entry->pfn,
+				   entry->dev_addr, entry->size,
+				   dir2name[entry->direction],
+				   maperr2str[entry->map_err_type]);
+		}
+		spin_unlock_irqrestore(&bucket->lock, flags);
+	}
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(dump);
+
+static int __init dma_debug_fs_init(void)
+{
+	struct dentry *dentry = debugfs_create_dir("dma-api", NULL);
+
+	debugfs_create_bool("disabled", 0444, dentry, &global_disable);
+	debugfs_create_u32("error_count", 0444, dentry, &error_count);
+	debugfs_create_u32("all_errors", 0644, dentry, &show_all_errors);
+	debugfs_create_u32("num_errors", 0644, dentry, &show_num_errors);
+	debugfs_create_u32("num_free_entries", 0444, dentry, &num_free_entries);
+	debugfs_create_u32("min_free_entries", 0444, dentry, &min_free_entries);
+	debugfs_create_u32("nr_total_entries", 0444, dentry, &nr_total_entries);
+	debugfs_create_file("driver_filter", 0644, dentry, NULL, &filter_fops);
+	debugfs_create_file("dump", 0444, dentry, NULL, &dump_fops);
+
+	return 0;
+}
+core_initcall_sync(dma_debug_fs_init);
+
+static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
+{
+	struct dma_debug_entry *entry;
+	unsigned long flags;
+	int count = 0, i;
+
+	for (i = 0; i < HASH_SIZE; ++i) {
+		spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
+		list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
+			if (entry->dev == dev) {
+				count += 1;
+				*out_entry = entry;
+			}
+		}
+		spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
+	}
+
+	return count;
+}
+
+static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct dma_debug_entry *entry;
+	int count;
+
+	if (dma_debug_disabled())
+		return 0;
+
+	switch (action) {
+	case BUS_NOTIFY_UNBOUND_DRIVER:
+		count = device_dma_allocations(dev, &entry);
+		if (count == 0)
+			break;
+		err_printk(dev, entry, "device driver has pending "
+				"DMA allocations while released from device "
+				"[count=%d]\n"
+				"One of leaked entries details: "
+				"[device address=0x%016llx] [size=%llu bytes] "
+				"[mapped with %s] [mapped as %s]\n",
+			count, entry->dev_addr, entry->size,
+			dir2name[entry->direction], type2name[entry->type]);
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+void dma_debug_add_bus(struct bus_type *bus)
+{
+	struct notifier_block *nb;
+
+	if (dma_debug_disabled())
+		return;
+
+	nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
+	if (nb == NULL) {
+		pr_err("dma_debug_add_bus: out of memory\n");
+		return;
+	}
+
+	nb->notifier_call = dma_debug_device_change;
+
+	bus_register_notifier(bus, nb);
+}
+
+static int dma_debug_init(void)
+{
+	int i, nr_pages;
+
+	/* Do not use dma_debug_initialized here, since we really want to be
+	 * called to set dma_debug_initialized
+	 */
+	if (global_disable)
+		return 0;
+
+	for (i = 0; i < HASH_SIZE; ++i) {
+		INIT_LIST_HEAD(&dma_entry_hash[i].list);
+		spin_lock_init(&dma_entry_hash[i].lock);
+	}
+
+	nr_pages = DIV_ROUND_UP(nr_prealloc_entries, DMA_DEBUG_DYNAMIC_ENTRIES);
+	for (i = 0; i < nr_pages; ++i)
+		dma_debug_create_entries(GFP_KERNEL);
+	if (num_free_entries >= nr_prealloc_entries) {
+		pr_info("preallocated %d debug entries\n", nr_total_entries);
+	} else if (num_free_entries > 0) {
+		pr_warn("%d debug entries requested but only %d allocated\n",
+			nr_prealloc_entries, nr_total_entries);
+	} else {
+		pr_err("debugging out of memory error - disabled\n");
+		global_disable = true;
+
+		return 0;
+	}
+	min_free_entries = num_free_entries;
+
+	dma_debug_initialized = true;
+
+	pr_info("debugging enabled by kernel config\n");
+	return 0;
+}
+core_initcall(dma_debug_init);
+
+static __init int dma_debug_cmdline(char *str)
+{
+	if (!str)
+		return -EINVAL;
+
+	if (strncmp(str, "off", 3) == 0) {
+		pr_info("debugging disabled on kernel command line\n");
+		global_disable = true;
+	}
+
+	return 1;
+}
+
+static __init int dma_debug_entries_cmdline(char *str)
+{
+	if (!str)
+		return -EINVAL;
+	if (!get_option(&str, &nr_prealloc_entries))
+		nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
+	return 1;
+}
+
+__setup("dma_debug=", dma_debug_cmdline);
+__setup("dma_debug_entries=", dma_debug_entries_cmdline);
+
+static void check_unmap(struct dma_debug_entry *ref)
+{
+	struct dma_debug_entry *entry;
+	struct hash_bucket *bucket;
+	unsigned long flags;
+
+	bucket = get_hash_bucket(ref, &flags);
+	entry = bucket_find_exact(bucket, ref);
+
+	if (!entry) {
+		/* must drop lock before calling dma_mapping_error */
+		put_hash_bucket(bucket, flags);
+
+		if (dma_mapping_error(ref->dev, ref->dev_addr)) {
+			err_printk(ref->dev, NULL,
+				   "device driver tries to free an "
+				   "invalid DMA memory address\n");
+		} else {
+			err_printk(ref->dev, NULL,
+				   "device driver tries to free DMA "
+				   "memory it has not allocated [device "
+				   "address=0x%016llx] [size=%llu bytes]\n",
+				   ref->dev_addr, ref->size);
+		}
+		return;
+	}
+
+	if (ref->size != entry->size) {
+		err_printk(ref->dev, entry, "device driver frees "
+			   "DMA memory with different size "
+			   "[device address=0x%016llx] [map size=%llu bytes] "
+			   "[unmap size=%llu bytes]\n",
+			   ref->dev_addr, entry->size, ref->size);
+	}
+
+	if (ref->type != entry->type) {
+		err_printk(ref->dev, entry, "device driver frees "
+			   "DMA memory with wrong function "
+			   "[device address=0x%016llx] [size=%llu bytes] "
+			   "[mapped as %s] [unmapped as %s]\n",
+			   ref->dev_addr, ref->size,
+			   type2name[entry->type], type2name[ref->type]);
+	} else if ((entry->type == dma_debug_coherent) &&
+		   (phys_addr(ref) != phys_addr(entry))) {
+		err_printk(ref->dev, entry, "device driver frees "
+			   "DMA memory with different CPU address "
+			   "[device address=0x%016llx] [size=%llu bytes] "
+			   "[cpu alloc address=0x%016llx] "
+			   "[cpu free address=0x%016llx]",
+			   ref->dev_addr, ref->size,
+			   phys_addr(entry),
+			   phys_addr(ref));
+	}
+
+	if (ref->sg_call_ents && ref->type == dma_debug_sg &&
+	    ref->sg_call_ents != entry->sg_call_ents) {
+		err_printk(ref->dev, entry, "device driver frees "
+			   "DMA sg list with different entry count "
+			   "[map count=%d] [unmap count=%d]\n",
+			   entry->sg_call_ents, ref->sg_call_ents);
+	}
+
+	/*
+	 * This may be no bug in reality - but most implementations of the
+	 * DMA API don't handle this properly, so check for it here
+	 */
+	if (ref->direction != entry->direction) {
+		err_printk(ref->dev, entry, "device driver frees "
+			   "DMA memory with different direction "
+			   "[device address=0x%016llx] [size=%llu bytes] "
+			   "[mapped with %s] [unmapped with %s]\n",
+			   ref->dev_addr, ref->size,
+			   dir2name[entry->direction],
+			   dir2name[ref->direction]);
+	}
+
+	/*
+	 * Drivers should use dma_mapping_error() to check the returned
+	 * addresses of dma_map_single() and dma_map_page().
+	 * If not, print this warning message. See Documentation/core-api/dma-api.rst.
+	 */
+	if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
+		err_printk(ref->dev, entry,
+			   "device driver failed to check map error"
+			   "[device address=0x%016llx] [size=%llu bytes] "
+			   "[mapped as %s]",
+			   ref->dev_addr, ref->size,
+			   type2name[entry->type]);
+	}
+
+	hash_bucket_del(entry);
+	dma_entry_free(entry);
+
+	put_hash_bucket(bucket, flags);
+}
+
+static void check_for_stack(struct device *dev,
+			    struct page *page, size_t offset)
+{
+	void *addr;
+	struct vm_struct *stack_vm_area = task_stack_vm_area(current);
+
+	if (!stack_vm_area) {
+		/* Stack is direct-mapped. */
+		if (PageHighMem(page))
+			return;
+		addr = page_address(page) + offset;
+		if (object_is_on_stack(addr))
+			err_printk(dev, NULL, "device driver maps memory from stack [addr=%p]\n", addr);
+	} else {
+		/* Stack is vmalloced. */
+		int i;
+
+		for (i = 0; i < stack_vm_area->nr_pages; i++) {
+			if (page != stack_vm_area->pages[i])
+				continue;
+
+			addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
+			err_printk(dev, NULL, "device driver maps memory from stack [probable addr=%p]\n", addr);
+			break;
+		}
+	}
+}
+
+static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
+{
+	if (memory_intersects(_stext, _etext, addr, len) ||
+	    memory_intersects(__start_rodata, __end_rodata, addr, len))
+		err_printk(dev, NULL, "device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
+}
+
+static void check_sync(struct device *dev,
+		       struct dma_debug_entry *ref,
+		       bool to_cpu)
+{
+	struct dma_debug_entry *entry;
+	struct hash_bucket *bucket;
+	unsigned long flags;
+
+	bucket = get_hash_bucket(ref, &flags);
+
+	entry = bucket_find_contain(&bucket, ref, &flags);
+
+	if (!entry) {
+		err_printk(dev, NULL, "device driver tries "
+				"to sync DMA memory it has not allocated "
+				"[device address=0x%016llx] [size=%llu bytes]\n",
+				(unsigned long long)ref->dev_addr, ref->size);
+		goto out;
+	}
+
+	if (ref->size > entry->size) {
+		err_printk(dev, entry, "device driver syncs"
+				" DMA memory outside allocated range "
+				"[device address=0x%016llx] "
+				"[allocation size=%llu bytes] "
+				"[sync offset+size=%llu]\n",
+				entry->dev_addr, entry->size,
+				ref->size);
+	}
+
+	if (entry->direction == DMA_BIDIRECTIONAL)
+		goto out;
+
+	if (ref->direction != entry->direction) {
+		err_printk(dev, entry, "device driver syncs "
+				"DMA memory with different direction "
+				"[device address=0x%016llx] [size=%llu bytes] "
+				"[mapped with %s] [synced with %s]\n",
+				(unsigned long long)ref->dev_addr, entry->size,
+				dir2name[entry->direction],
+				dir2name[ref->direction]);
+	}
+
+	if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
+		      !(ref->direction == DMA_TO_DEVICE))
+		err_printk(dev, entry, "device driver syncs "
+				"device read-only DMA memory for cpu "
+				"[device address=0x%016llx] [size=%llu bytes] "
+				"[mapped with %s] [synced with %s]\n",
+				(unsigned long long)ref->dev_addr, entry->size,
+				dir2name[entry->direction],
+				dir2name[ref->direction]);
+
+	if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
+		       !(ref->direction == DMA_FROM_DEVICE))
+		err_printk(dev, entry, "device driver syncs "
+				"device write-only DMA memory to device "
+				"[device address=0x%016llx] [size=%llu bytes] "
+				"[mapped with %s] [synced with %s]\n",
+				(unsigned long long)ref->dev_addr, entry->size,
+				dir2name[entry->direction],
+				dir2name[ref->direction]);
+
+	if (ref->sg_call_ents && ref->type == dma_debug_sg &&
+	    ref->sg_call_ents != entry->sg_call_ents) {
+		err_printk(ref->dev, entry, "device driver syncs "
+			   "DMA sg list with different entry count "
+			   "[map count=%d] [sync count=%d]\n",
+			   entry->sg_call_ents, ref->sg_call_ents);
+	}
+
+out:
+	put_hash_bucket(bucket, flags);
+}
+
+static void check_sg_segment(struct device *dev, struct scatterlist *sg)
+{
+#ifdef CONFIG_DMA_API_DEBUG_SG
+	unsigned int max_seg = dma_get_max_seg_size(dev);
+	u64 start, end, boundary = dma_get_seg_boundary(dev);
+
+	/*
+	 * Either the driver forgot to set dma_parms appropriately, or
+	 * whoever generated the list forgot to check them.
+	 */
+	if (sg->length > max_seg)
+		err_printk(dev, NULL, "mapping sg segment longer than device claims to support [len=%u] [max=%u]\n",
+			   sg->length, max_seg);
+	/*
+	 * In some cases this could potentially be the DMA API
+	 * implementation's fault, but it would usually imply that
+	 * the scatterlist was built inappropriately to begin with.
+	 */
+	start = sg_dma_address(sg);
+	end = start + sg_dma_len(sg) - 1;
+	if ((start ^ end) & ~boundary)
+		err_printk(dev, NULL, "mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n",
+			   start, end, boundary);
+#endif
+}
+
+void debug_dma_map_single(struct device *dev, const void *addr,
+			    unsigned long len)
+{
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	if (!virt_addr_valid(addr))
+		err_printk(dev, NULL, "device driver maps memory from invalid area [addr=%p] [len=%lu]\n",
+			   addr, len);
+
+	if (is_vmalloc_addr(addr))
+		err_printk(dev, NULL, "device driver maps memory from vmalloc area [addr=%p] [len=%lu]\n",
+			   addr, len);
+}
+EXPORT_SYMBOL(debug_dma_map_single);
+
+void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
+			size_t size, int direction, dma_addr_t dma_addr,
+			unsigned long attrs)
+{
+	struct dma_debug_entry *entry;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	if (dma_mapping_error(dev, dma_addr))
+		return;
+
+	entry = dma_entry_alloc();
+	if (!entry)
+		return;
+
+	entry->dev       = dev;
+	entry->type      = dma_debug_single;
+	entry->pfn	 = page_to_pfn(page);
+	entry->offset	 = offset;
+	entry->dev_addr  = dma_addr;
+	entry->size      = size;
+	entry->direction = direction;
+	entry->map_err_type = MAP_ERR_NOT_CHECKED;
+
+	check_for_stack(dev, page, offset);
+
+	if (!PageHighMem(page)) {
+		void *addr = page_address(page) + offset;
+
+		check_for_illegal_area(dev, addr, size);
+	}
+
+	add_dma_entry(entry, attrs);
+}
+
+void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+	struct dma_debug_entry ref;
+	struct dma_debug_entry *entry;
+	struct hash_bucket *bucket;
+	unsigned long flags;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	ref.dev = dev;
+	ref.dev_addr = dma_addr;
+	bucket = get_hash_bucket(&ref, &flags);
+
+	list_for_each_entry(entry, &bucket->list, list) {
+		if (!exact_match(&ref, entry))
+			continue;
+
+		/*
+		 * The same physical address can be mapped multiple
+		 * times. Without a hardware IOMMU this results in the
+		 * same device addresses being put into the dma-debug
+		 * hash multiple times too. This can result in false
+		 * positives being reported. Therefore we implement a
+		 * best-fit algorithm here which updates the first entry
+		 * from the hash which fits the reference value and is
+		 * not currently listed as being checked.
+		 */
+		if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
+			entry->map_err_type = MAP_ERR_CHECKED;
+			break;
+		}
+	}
+
+	put_hash_bucket(bucket, flags);
+}
+EXPORT_SYMBOL(debug_dma_mapping_error);
+
+void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
+			  size_t size, int direction)
+{
+	struct dma_debug_entry ref = {
+		.type           = dma_debug_single,
+		.dev            = dev,
+		.dev_addr       = addr,
+		.size           = size,
+		.direction      = direction,
+	};
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+	check_unmap(&ref);
+}
+
+void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
+		      int nents, int mapped_ents, int direction,
+		      unsigned long attrs)
+{
+	struct dma_debug_entry *entry;
+	struct scatterlist *s;
+	int i;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	for_each_sg(sg, s, nents, i) {
+		check_for_stack(dev, sg_page(s), s->offset);
+		if (!PageHighMem(sg_page(s)))
+			check_for_illegal_area(dev, sg_virt(s), s->length);
+	}
+
+	for_each_sg(sg, s, mapped_ents, i) {
+		entry = dma_entry_alloc();
+		if (!entry)
+			return;
+
+		entry->type           = dma_debug_sg;
+		entry->dev            = dev;
+		entry->pfn	      = page_to_pfn(sg_page(s));
+		entry->offset	      = s->offset;
+		entry->size           = sg_dma_len(s);
+		entry->dev_addr       = sg_dma_address(s);
+		entry->direction      = direction;
+		entry->sg_call_ents   = nents;
+		entry->sg_mapped_ents = mapped_ents;
+
+		check_sg_segment(dev, s);
+
+		add_dma_entry(entry, attrs);
+	}
+}
+
+static int get_nr_mapped_entries(struct device *dev,
+				 struct dma_debug_entry *ref)
+{
+	struct dma_debug_entry *entry;
+	struct hash_bucket *bucket;
+	unsigned long flags;
+	int mapped_ents;
+
+	bucket       = get_hash_bucket(ref, &flags);
+	entry        = bucket_find_exact(bucket, ref);
+	mapped_ents  = 0;
+
+	if (entry)
+		mapped_ents = entry->sg_mapped_ents;
+	put_hash_bucket(bucket, flags);
+
+	return mapped_ents;
+}
+
+void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
+			int nelems, int dir)
+{
+	struct scatterlist *s;
+	int mapped_ents = 0, i;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	for_each_sg(sglist, s, nelems, i) {
+
+		struct dma_debug_entry ref = {
+			.type           = dma_debug_sg,
+			.dev            = dev,
+			.pfn		= page_to_pfn(sg_page(s)),
+			.offset		= s->offset,
+			.dev_addr       = sg_dma_address(s),
+			.size           = sg_dma_len(s),
+			.direction      = dir,
+			.sg_call_ents   = nelems,
+		};
+
+		if (mapped_ents && i >= mapped_ents)
+			break;
+
+		if (!i)
+			mapped_ents = get_nr_mapped_entries(dev, &ref);
+
+		check_unmap(&ref);
+	}
+}
+
+void debug_dma_alloc_coherent(struct device *dev, size_t size,
+			      dma_addr_t dma_addr, void *virt,
+			      unsigned long attrs)
+{
+	struct dma_debug_entry *entry;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	if (unlikely(virt == NULL))
+		return;
+
+	/* handle vmalloc and linear addresses */
+	if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
+		return;
+
+	entry = dma_entry_alloc();
+	if (!entry)
+		return;
+
+	entry->type      = dma_debug_coherent;
+	entry->dev       = dev;
+	entry->offset	 = offset_in_page(virt);
+	entry->size      = size;
+	entry->dev_addr  = dma_addr;
+	entry->direction = DMA_BIDIRECTIONAL;
+
+	if (is_vmalloc_addr(virt))
+		entry->pfn = vmalloc_to_pfn(virt);
+	else
+		entry->pfn = page_to_pfn(virt_to_page(virt));
+
+	add_dma_entry(entry, attrs);
+}
+
+void debug_dma_free_coherent(struct device *dev, size_t size,
+			 void *virt, dma_addr_t addr)
+{
+	struct dma_debug_entry ref = {
+		.type           = dma_debug_coherent,
+		.dev            = dev,
+		.offset		= offset_in_page(virt),
+		.dev_addr       = addr,
+		.size           = size,
+		.direction      = DMA_BIDIRECTIONAL,
+	};
+
+	/* handle vmalloc and linear addresses */
+	if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
+		return;
+
+	if (is_vmalloc_addr(virt))
+		ref.pfn = vmalloc_to_pfn(virt);
+	else
+		ref.pfn = page_to_pfn(virt_to_page(virt));
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	check_unmap(&ref);
+}
+
+void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
+			    int direction, dma_addr_t dma_addr,
+			    unsigned long attrs)
+{
+	struct dma_debug_entry *entry;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	entry = dma_entry_alloc();
+	if (!entry)
+		return;
+
+	entry->type		= dma_debug_resource;
+	entry->dev		= dev;
+	entry->pfn		= PHYS_PFN(addr);
+	entry->offset		= offset_in_page(addr);
+	entry->size		= size;
+	entry->dev_addr		= dma_addr;
+	entry->direction	= direction;
+	entry->map_err_type	= MAP_ERR_NOT_CHECKED;
+
+	add_dma_entry(entry, attrs);
+}
+
+void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
+			      size_t size, int direction)
+{
+	struct dma_debug_entry ref = {
+		.type           = dma_debug_resource,
+		.dev            = dev,
+		.dev_addr       = dma_addr,
+		.size           = size,
+		.direction      = direction,
+	};
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	check_unmap(&ref);
+}
+
+void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
+				   size_t size, int direction)
+{
+	struct dma_debug_entry ref;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	ref.type         = dma_debug_single;
+	ref.dev          = dev;
+	ref.dev_addr     = dma_handle;
+	ref.size         = size;
+	ref.direction    = direction;
+	ref.sg_call_ents = 0;
+
+	check_sync(dev, &ref, true);
+}
+
+void debug_dma_sync_single_for_device(struct device *dev,
+				      dma_addr_t dma_handle, size_t size,
+				      int direction)
+{
+	struct dma_debug_entry ref;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	ref.type         = dma_debug_single;
+	ref.dev          = dev;
+	ref.dev_addr     = dma_handle;
+	ref.size         = size;
+	ref.direction    = direction;
+	ref.sg_call_ents = 0;
+
+	check_sync(dev, &ref, false);
+}
+
+void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
+			       int nelems, int direction)
+{
+	struct scatterlist *s;
+	int mapped_ents = 0, i;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	for_each_sg(sg, s, nelems, i) {
+
+		struct dma_debug_entry ref = {
+			.type           = dma_debug_sg,
+			.dev            = dev,
+			.pfn		= page_to_pfn(sg_page(s)),
+			.offset		= s->offset,
+			.dev_addr       = sg_dma_address(s),
+			.size           = sg_dma_len(s),
+			.direction      = direction,
+			.sg_call_ents   = nelems,
+		};
+
+		if (!i)
+			mapped_ents = get_nr_mapped_entries(dev, &ref);
+
+		if (i >= mapped_ents)
+			break;
+
+		check_sync(dev, &ref, true);
+	}
+}
+
+void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
+				  int nelems, int direction)
+{
+	struct scatterlist *s;
+	int mapped_ents = 0, i;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	for_each_sg(sg, s, nelems, i) {
+
+		struct dma_debug_entry ref = {
+			.type           = dma_debug_sg,
+			.dev            = dev,
+			.pfn		= page_to_pfn(sg_page(s)),
+			.offset		= s->offset,
+			.dev_addr       = sg_dma_address(s),
+			.size           = sg_dma_len(s),
+			.direction      = direction,
+			.sg_call_ents   = nelems,
+		};
+		if (!i)
+			mapped_ents = get_nr_mapped_entries(dev, &ref);
+
+		if (i >= mapped_ents)
+			break;
+
+		check_sync(dev, &ref, false);
+	}
+}
+
+static int __init dma_debug_driver_setup(char *str)
+{
+	int i;
+
+	for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
+		current_driver_name[i] = *str;
+		if (*str == 0)
+			break;
+	}
+
+	if (current_driver_name[0])
+		pr_info("enable driver filter for driver [%s]\n",
+			current_driver_name);
+
+
+	return 1;
+}
+__setup("dma_debug_driver=", dma_debug_driver_setup);
diff --git a/kernel/dma/debug.h b/kernel/dma/debug.h
new file mode 100644
index 000000000..f525197d3
--- /dev/null
+++ b/kernel/dma/debug.h
@@ -0,0 +1,130 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * Author: Joerg Roedel <joerg.roedel@amd.com>
+ */
+
+#ifndef _KERNEL_DMA_DEBUG_H
+#define _KERNEL_DMA_DEBUG_H
+
+#ifdef CONFIG_DMA_API_DEBUG
+extern void debug_dma_map_page(struct device *dev, struct page *page,
+			       size_t offset, size_t size,
+			       int direction, dma_addr_t dma_addr,
+			       unsigned long attrs);
+
+extern void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
+				 size_t size, int direction);
+
+extern void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
+			     int nents, int mapped_ents, int direction,
+			     unsigned long attrs);
+
+extern void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
+			       int nelems, int dir);
+
+extern void debug_dma_alloc_coherent(struct device *dev, size_t size,
+				     dma_addr_t dma_addr, void *virt,
+				     unsigned long attrs);
+
+extern void debug_dma_free_coherent(struct device *dev, size_t size,
+				    void *virt, dma_addr_t addr);
+
+extern void debug_dma_map_resource(struct device *dev, phys_addr_t addr,
+				   size_t size, int direction,
+				   dma_addr_t dma_addr,
+				   unsigned long attrs);
+
+extern void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
+				     size_t size, int direction);
+
+extern void debug_dma_sync_single_for_cpu(struct device *dev,
+					  dma_addr_t dma_handle, size_t size,
+					  int direction);
+
+extern void debug_dma_sync_single_for_device(struct device *dev,
+					     dma_addr_t dma_handle,
+					     size_t size, int direction);
+
+extern void debug_dma_sync_sg_for_cpu(struct device *dev,
+				      struct scatterlist *sg,
+				      int nelems, int direction);
+
+extern void debug_dma_sync_sg_for_device(struct device *dev,
+					 struct scatterlist *sg,
+					 int nelems, int direction);
+#else /* CONFIG_DMA_API_DEBUG */
+static inline void debug_dma_map_page(struct device *dev, struct page *page,
+				      size_t offset, size_t size,
+				      int direction, dma_addr_t dma_addr,
+				      unsigned long attrs)
+{
+}
+
+static inline void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
+					size_t size, int direction)
+{
+}
+
+static inline void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
+				    int nents, int mapped_ents, int direction,
+				    unsigned long attrs)
+{
+}
+
+static inline void debug_dma_unmap_sg(struct device *dev,
+				      struct scatterlist *sglist,
+				      int nelems, int dir)
+{
+}
+
+static inline void debug_dma_alloc_coherent(struct device *dev, size_t size,
+					    dma_addr_t dma_addr, void *virt,
+					    unsigned long attrs)
+{
+}
+
+static inline void debug_dma_free_coherent(struct device *dev, size_t size,
+					   void *virt, dma_addr_t addr)
+{
+}
+
+static inline void debug_dma_map_resource(struct device *dev, phys_addr_t addr,
+					  size_t size, int direction,
+					  dma_addr_t dma_addr,
+					  unsigned long attrs)
+{
+}
+
+static inline void debug_dma_unmap_resource(struct device *dev,
+					    dma_addr_t dma_addr, size_t size,
+					    int direction)
+{
+}
+
+static inline void debug_dma_sync_single_for_cpu(struct device *dev,
+						 dma_addr_t dma_handle,
+						 size_t size, int direction)
+{
+}
+
+static inline void debug_dma_sync_single_for_device(struct device *dev,
+						    dma_addr_t dma_handle,
+						    size_t size, int direction)
+{
+}
+
+static inline void debug_dma_sync_sg_for_cpu(struct device *dev,
+					     struct scatterlist *sg,
+					     int nelems, int direction)
+{
+}
+
+static inline void debug_dma_sync_sg_for_device(struct device *dev,
+						struct scatterlist *sg,
+						int nelems, int direction)
+{
+}
+#endif /* CONFIG_DMA_API_DEBUG */
+#endif /* _KERNEL_DMA_DEBUG_H */
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
new file mode 100644
index 000000000..63859a101
--- /dev/null
+++ b/kernel/dma/direct.c
@@ -0,0 +1,656 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018-2020 Christoph Hellwig.
+ *
+ * DMA operations that map physical memory directly without using an IOMMU.
+ */
+#include <linux/memblock.h> /* for max_pfn */
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/dma-map-ops.h>
+#include <linux/scatterlist.h>
+#include <linux/pfn.h>
+#include <linux/vmalloc.h>
+#include <linux/set_memory.h>
+#include <linux/slab.h>
+#include "direct.h"
+
+/*
+ * Most architectures use ZONE_DMA for the first 16 Megabytes, but some use
+ * it for entirely different regions. In that case the arch code needs to
+ * override the variable below for dma-direct to work properly.
+ */
+unsigned int zone_dma_bits __ro_after_init = 24;
+
+static inline dma_addr_t phys_to_dma_direct(struct device *dev,
+		phys_addr_t phys)
+{
+	if (force_dma_unencrypted(dev))
+		return phys_to_dma_unencrypted(dev, phys);
+	return phys_to_dma(dev, phys);
+}
+
+static inline struct page *dma_direct_to_page(struct device *dev,
+		dma_addr_t dma_addr)
+{
+	return pfn_to_page(PHYS_PFN(dma_to_phys(dev, dma_addr)));
+}
+
+u64 dma_direct_get_required_mask(struct device *dev)
+{
+	phys_addr_t phys = (phys_addr_t)(max_pfn - 1) << PAGE_SHIFT;
+	u64 max_dma = phys_to_dma_direct(dev, phys);
+
+	return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;
+}
+
+static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
+				  u64 *phys_limit)
+{
+	u64 dma_limit = min_not_zero(dma_mask, dev->bus_dma_limit);
+
+	/*
+	 * Optimistically try the zone that the physical address mask falls
+	 * into first.  If that returns memory that isn't actually addressable
+	 * we will fallback to the next lower zone and try again.
+	 *
+	 * Note that GFP_DMA32 and GFP_DMA are no ops without the corresponding
+	 * zones.
+	 */
+	*phys_limit = dma_to_phys(dev, dma_limit);
+	if (*phys_limit <= DMA_BIT_MASK(zone_dma_bits))
+		return GFP_DMA;
+	if (*phys_limit <= DMA_BIT_MASK(32))
+		return GFP_DMA32;
+	return 0;
+}
+
+static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
+{
+	dma_addr_t dma_addr = phys_to_dma_direct(dev, phys);
+
+	if (dma_addr == DMA_MAPPING_ERROR)
+		return false;
+	return dma_addr + size - 1 <=
+		min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);
+}
+
+static int dma_set_decrypted(struct device *dev, void *vaddr, size_t size)
+{
+	if (!force_dma_unencrypted(dev))
+		return 0;
+	return set_memory_decrypted((unsigned long)vaddr, PFN_UP(size));
+}
+
+static int dma_set_encrypted(struct device *dev, void *vaddr, size_t size)
+{
+	int ret;
+
+	if (!force_dma_unencrypted(dev))
+		return 0;
+	ret = set_memory_encrypted((unsigned long)vaddr, PFN_UP(size));
+	if (ret)
+		pr_warn_ratelimited("leaking DMA memory that can't be re-encrypted\n");
+	return ret;
+}
+
+static void __dma_direct_free_pages(struct device *dev, struct page *page,
+				    size_t size)
+{
+	if (swiotlb_free(dev, page, size))
+		return;
+	dma_free_contiguous(dev, page, size);
+}
+
+static struct page *dma_direct_alloc_swiotlb(struct device *dev, size_t size)
+{
+	struct page *page = swiotlb_alloc(dev, size);
+
+	if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
+		swiotlb_free(dev, page, size);
+		return NULL;
+	}
+
+	return page;
+}
+
+static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
+		gfp_t gfp, bool allow_highmem)
+{
+	int node = dev_to_node(dev);
+	struct page *page = NULL;
+	u64 phys_limit;
+
+	WARN_ON_ONCE(!PAGE_ALIGNED(size));
+
+	if (is_swiotlb_for_alloc(dev))
+		return dma_direct_alloc_swiotlb(dev, size);
+
+	gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
+					   &phys_limit);
+	page = dma_alloc_contiguous(dev, size, gfp);
+	if (page) {
+		if (!dma_coherent_ok(dev, page_to_phys(page), size) ||
+		    (!allow_highmem && PageHighMem(page))) {
+			dma_free_contiguous(dev, page, size);
+			page = NULL;
+		}
+	}
+again:
+	if (!page)
+		page = alloc_pages_node(node, gfp, get_order(size));
+	if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
+		dma_free_contiguous(dev, page, size);
+		page = NULL;
+
+		if (IS_ENABLED(CONFIG_ZONE_DMA32) &&
+		    phys_limit < DMA_BIT_MASK(64) &&
+		    !(gfp & (GFP_DMA32 | GFP_DMA))) {
+			gfp |= GFP_DMA32;
+			goto again;
+		}
+
+		if (IS_ENABLED(CONFIG_ZONE_DMA) && !(gfp & GFP_DMA)) {
+			gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
+			goto again;
+		}
+	}
+
+	return page;
+}
+
+/*
+ * Check if a potentially blocking operations needs to dip into the atomic
+ * pools for the given device/gfp.
+ */
+static bool dma_direct_use_pool(struct device *dev, gfp_t gfp)
+{
+	return !gfpflags_allow_blocking(gfp) && !is_swiotlb_for_alloc(dev);
+}
+
+static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, gfp_t gfp)
+{
+	struct page *page;
+	u64 phys_mask;
+	void *ret;
+
+	if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_DMA_COHERENT_POOL)))
+		return NULL;
+
+	gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
+					   &phys_mask);
+	page = dma_alloc_from_pool(dev, size, &ret, gfp, dma_coherent_ok);
+	if (!page)
+		return NULL;
+	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+	return ret;
+}
+
+static void *dma_direct_alloc_no_mapping(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, gfp_t gfp)
+{
+	struct page *page;
+
+	page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true);
+	if (!page)
+		return NULL;
+
+	/* remove any dirty cache lines on the kernel alias */
+	if (!PageHighMem(page))
+		arch_dma_prep_coherent(page, size);
+
+	/* return the page pointer as the opaque cookie */
+	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+	return page;
+}
+
+void *dma_direct_alloc(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
+{
+	bool remap = false, set_uncached = false;
+	struct page *page;
+	void *ret;
+
+	size = PAGE_ALIGN(size);
+	if (attrs & DMA_ATTR_NO_WARN)
+		gfp |= __GFP_NOWARN;
+
+	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
+	    !force_dma_unencrypted(dev) && !is_swiotlb_for_alloc(dev))
+		return dma_direct_alloc_no_mapping(dev, size, dma_handle, gfp);
+
+	if (!dev_is_dma_coherent(dev)) {
+		/*
+		 * Fallback to the arch handler if it exists.  This should
+		 * eventually go away.
+		 */
+		if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
+		    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
+		    !IS_ENABLED(CONFIG_DMA_GLOBAL_POOL) &&
+		    !is_swiotlb_for_alloc(dev))
+			return arch_dma_alloc(dev, size, dma_handle, gfp,
+					      attrs);
+
+		/*
+		 * If there is a global pool, always allocate from it for
+		 * non-coherent devices.
+		 */
+		if (IS_ENABLED(CONFIG_DMA_GLOBAL_POOL))
+			return dma_alloc_from_global_coherent(dev, size,
+					dma_handle);
+
+		/*
+		 * Otherwise remap if the architecture is asking for it.  But
+		 * given that remapping memory is a blocking operation we'll
+		 * instead have to dip into the atomic pools.
+		 */
+		remap = IS_ENABLED(CONFIG_DMA_DIRECT_REMAP);
+		if (remap) {
+			if (dma_direct_use_pool(dev, gfp))
+				return dma_direct_alloc_from_pool(dev, size,
+						dma_handle, gfp);
+		} else {
+			if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED))
+				return NULL;
+			set_uncached = true;
+		}
+	}
+
+	/*
+	 * Decrypting memory may block, so allocate the memory from the atomic
+	 * pools if we can't block.
+	 */
+	if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp))
+		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
+
+	/* we always manually zero the memory once we are done */
+	page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true);
+	if (!page)
+		return NULL;
+
+	/*
+	 * dma_alloc_contiguous can return highmem pages depending on a
+	 * combination the cma= arguments and per-arch setup.  These need to be
+	 * remapped to return a kernel virtual address.
+	 */
+	if (PageHighMem(page)) {
+		remap = true;
+		set_uncached = false;
+	}
+
+	if (remap) {
+		pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs);
+
+		if (force_dma_unencrypted(dev))
+			prot = pgprot_decrypted(prot);
+
+		/* remove any dirty cache lines on the kernel alias */
+		arch_dma_prep_coherent(page, size);
+
+		/* create a coherent mapping */
+		ret = dma_common_contiguous_remap(page, size, prot,
+				__builtin_return_address(0));
+		if (!ret)
+			goto out_free_pages;
+	} else {
+		ret = page_address(page);
+		if (dma_set_decrypted(dev, ret, size))
+			goto out_free_pages;
+	}
+
+	memset(ret, 0, size);
+
+	if (set_uncached) {
+		arch_dma_prep_coherent(page, size);
+		ret = arch_dma_set_uncached(ret, size);
+		if (IS_ERR(ret))
+			goto out_encrypt_pages;
+	}
+
+	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+	return ret;
+
+out_encrypt_pages:
+	if (dma_set_encrypted(dev, page_address(page), size))
+		return NULL;
+out_free_pages:
+	__dma_direct_free_pages(dev, page, size);
+	return NULL;
+}
+
+void dma_direct_free(struct device *dev, size_t size,
+		void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs)
+{
+	unsigned int page_order = get_order(size);
+
+	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
+	    !force_dma_unencrypted(dev) && !is_swiotlb_for_alloc(dev)) {
+		/* cpu_addr is a struct page cookie, not a kernel address */
+		dma_free_contiguous(dev, cpu_addr, size);
+		return;
+	}
+
+	if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
+	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
+	    !IS_ENABLED(CONFIG_DMA_GLOBAL_POOL) &&
+	    !dev_is_dma_coherent(dev) &&
+	    !is_swiotlb_for_alloc(dev)) {
+		arch_dma_free(dev, size, cpu_addr, dma_addr, attrs);
+		return;
+	}
+
+	if (IS_ENABLED(CONFIG_DMA_GLOBAL_POOL) &&
+	    !dev_is_dma_coherent(dev)) {
+		if (!dma_release_from_global_coherent(page_order, cpu_addr))
+			WARN_ON_ONCE(1);
+		return;
+	}
+
+	/* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */
+	if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
+	    dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size)))
+		return;
+
+	if (is_vmalloc_addr(cpu_addr)) {
+		vunmap(cpu_addr);
+	} else {
+		if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_CLEAR_UNCACHED))
+			arch_dma_clear_uncached(cpu_addr, size);
+		if (dma_set_encrypted(dev, cpu_addr, size))
+			return;
+	}
+
+	__dma_direct_free_pages(dev, dma_direct_to_page(dev, dma_addr), size);
+}
+
+struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
+{
+	struct page *page;
+	void *ret;
+
+	if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp))
+		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
+
+	page = __dma_direct_alloc_pages(dev, size, gfp, false);
+	if (!page)
+		return NULL;
+
+	ret = page_address(page);
+	if (dma_set_decrypted(dev, ret, size))
+		goto out_free_pages;
+	memset(ret, 0, size);
+	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+	return page;
+out_free_pages:
+	__dma_direct_free_pages(dev, page, size);
+	return NULL;
+}
+
+void dma_direct_free_pages(struct device *dev, size_t size,
+		struct page *page, dma_addr_t dma_addr,
+		enum dma_data_direction dir)
+{
+	void *vaddr = page_address(page);
+
+	/* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */
+	if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
+	    dma_free_from_pool(dev, vaddr, size))
+		return;
+
+	if (dma_set_encrypted(dev, vaddr, size))
+		return;
+	__dma_direct_free_pages(dev, page, size);
+}
+
+#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
+    defined(CONFIG_SWIOTLB)
+void dma_direct_sync_sg_for_device(struct device *dev,
+		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	for_each_sg(sgl, sg, nents, i) {
+		phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg));
+
+		if (unlikely(is_swiotlb_buffer(dev, paddr)))
+			swiotlb_sync_single_for_device(dev, paddr, sg->length,
+						       dir);
+
+		if (!dev_is_dma_coherent(dev))
+			arch_sync_dma_for_device(paddr, sg->length,
+					dir);
+	}
+}
+#endif
+
+#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
+    defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) || \
+    defined(CONFIG_SWIOTLB)
+void dma_direct_sync_sg_for_cpu(struct device *dev,
+		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	for_each_sg(sgl, sg, nents, i) {
+		phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg));
+
+		if (!dev_is_dma_coherent(dev))
+			arch_sync_dma_for_cpu(paddr, sg->length, dir);
+
+		if (unlikely(is_swiotlb_buffer(dev, paddr)))
+			swiotlb_sync_single_for_cpu(dev, paddr, sg->length,
+						    dir);
+
+		if (dir == DMA_FROM_DEVICE)
+			arch_dma_mark_clean(paddr, sg->length);
+	}
+
+	if (!dev_is_dma_coherent(dev))
+		arch_sync_dma_for_cpu_all();
+}
+
+/*
+ * Unmaps segments, except for ones marked as pci_p2pdma which do not
+ * require any further action as they contain a bus address.
+ */
+void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
+		int nents, enum dma_data_direction dir, unsigned long attrs)
+{
+	struct scatterlist *sg;
+	int i;
+
+	for_each_sg(sgl,  sg, nents, i) {
+		if (sg_is_dma_bus_address(sg))
+			sg_dma_unmark_bus_address(sg);
+		else
+			dma_direct_unmap_page(dev, sg->dma_address,
+					      sg_dma_len(sg), dir, attrs);
+	}
+}
+#endif
+
+int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
+		enum dma_data_direction dir, unsigned long attrs)
+{
+	struct pci_p2pdma_map_state p2pdma_state = {};
+	enum pci_p2pdma_map_type map;
+	struct scatterlist *sg;
+	int i, ret;
+
+	for_each_sg(sgl, sg, nents, i) {
+		if (is_pci_p2pdma_page(sg_page(sg))) {
+			map = pci_p2pdma_map_segment(&p2pdma_state, dev, sg);
+			switch (map) {
+			case PCI_P2PDMA_MAP_BUS_ADDR:
+				continue;
+			case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE:
+				/*
+				 * Any P2P mapping that traverses the PCI
+				 * host bridge must be mapped with CPU physical
+				 * address and not PCI bus addresses. This is
+				 * done with dma_direct_map_page() below.
+				 */
+				break;
+			default:
+				ret = -EREMOTEIO;
+				goto out_unmap;
+			}
+		}
+
+		sg->dma_address = dma_direct_map_page(dev, sg_page(sg),
+				sg->offset, sg->length, dir, attrs);
+		if (sg->dma_address == DMA_MAPPING_ERROR) {
+			ret = -EIO;
+			goto out_unmap;
+		}
+		sg_dma_len(sg) = sg->length;
+	}
+
+	return nents;
+
+out_unmap:
+	dma_direct_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
+	return ret;
+}
+
+dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
+		size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+	dma_addr_t dma_addr = paddr;
+
+	if (unlikely(!dma_capable(dev, dma_addr, size, false))) {
+		dev_err_once(dev,
+			     "DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
+			     &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit);
+		WARN_ON_ONCE(1);
+		return DMA_MAPPING_ERROR;
+	}
+
+	return dma_addr;
+}
+
+int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt,
+		void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		unsigned long attrs)
+{
+	struct page *page = dma_direct_to_page(dev, dma_addr);
+	int ret;
+
+	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
+	if (!ret)
+		sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
+	return ret;
+}
+
+bool dma_direct_can_mmap(struct device *dev)
+{
+	return dev_is_dma_coherent(dev) ||
+		IS_ENABLED(CONFIG_DMA_NONCOHERENT_MMAP);
+}
+
+int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma,
+		void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		unsigned long attrs)
+{
+	unsigned long user_count = vma_pages(vma);
+	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	unsigned long pfn = PHYS_PFN(dma_to_phys(dev, dma_addr));
+	int ret = -ENXIO;
+
+	vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
+	if (force_dma_unencrypted(dev))
+		vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
+
+	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
+		return ret;
+	if (dma_mmap_from_global_coherent(vma, cpu_addr, size, &ret))
+		return ret;
+
+	if (vma->vm_pgoff >= count || user_count > count - vma->vm_pgoff)
+		return -ENXIO;
+	return remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff,
+			user_count << PAGE_SHIFT, vma->vm_page_prot);
+}
+
+int dma_direct_supported(struct device *dev, u64 mask)
+{
+	u64 min_mask = (max_pfn - 1) << PAGE_SHIFT;
+
+	/*
+	 * Because 32-bit DMA masks are so common we expect every architecture
+	 * to be able to satisfy them - either by not supporting more physical
+	 * memory, or by providing a ZONE_DMA32.  If neither is the case, the
+	 * architecture needs to use an IOMMU instead of the direct mapping.
+	 */
+	if (mask >= DMA_BIT_MASK(32))
+		return 1;
+
+	/*
+	 * This check needs to be against the actual bit mask value, so use
+	 * phys_to_dma_unencrypted() here so that the SME encryption mask isn't
+	 * part of the check.
+	 */
+	if (IS_ENABLED(CONFIG_ZONE_DMA))
+		min_mask = min_t(u64, min_mask, DMA_BIT_MASK(zone_dma_bits));
+	return mask >= phys_to_dma_unencrypted(dev, min_mask);
+}
+
+size_t dma_direct_max_mapping_size(struct device *dev)
+{
+	/* If SWIOTLB is active, use its maximum mapping size */
+	if (is_swiotlb_active(dev) &&
+	    (dma_addressing_limited(dev) || is_swiotlb_force_bounce(dev)))
+		return swiotlb_max_mapping_size(dev);
+	return SIZE_MAX;
+}
+
+bool dma_direct_need_sync(struct device *dev, dma_addr_t dma_addr)
+{
+	return !dev_is_dma_coherent(dev) ||
+	       is_swiotlb_buffer(dev, dma_to_phys(dev, dma_addr));
+}
+
+/**
+ * dma_direct_set_offset - Assign scalar offset for a single DMA range.
+ * @dev:	device pointer; needed to "own" the alloced memory.
+ * @cpu_start:  beginning of memory region covered by this offset.
+ * @dma_start:  beginning of DMA/PCI region covered by this offset.
+ * @size:	size of the region.
+ *
+ * This is for the simple case of a uniform offset which cannot
+ * be discovered by "dma-ranges".
+ *
+ * It returns -ENOMEM if out of memory, -EINVAL if a map
+ * already exists, 0 otherwise.
+ *
+ * Note: any call to this from a driver is a bug.  The mapping needs
+ * to be described by the device tree or other firmware interfaces.
+ */
+int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start,
+			 dma_addr_t dma_start, u64 size)
+{
+	struct bus_dma_region *map;
+	u64 offset = (u64)cpu_start - (u64)dma_start;
+
+	if (dev->dma_range_map) {
+		dev_err(dev, "attempt to add DMA range to existing map\n");
+		return -EINVAL;
+	}
+
+	if (!offset)
+		return 0;
+
+	map = kcalloc(2, sizeof(*map), GFP_KERNEL);
+	if (!map)
+		return -ENOMEM;
+	map[0].cpu_start = cpu_start;
+	map[0].dma_start = dma_start;
+	map[0].offset = offset;
+	map[0].size = size;
+	dev->dma_range_map = map;
+	return 0;
+}
diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h
new file mode 100644
index 000000000..e38ffc5e6
--- /dev/null
+++ b/kernel/dma/direct.h
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2018 Christoph Hellwig.
+ *
+ * DMA operations that map physical memory directly without using an IOMMU.
+ */
+#ifndef _KERNEL_DMA_DIRECT_H
+#define _KERNEL_DMA_DIRECT_H
+
+#include <linux/dma-direct.h>
+#include <linux/memremap.h>
+
+int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt,
+		void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		unsigned long attrs);
+bool dma_direct_can_mmap(struct device *dev);
+int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma,
+		void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		unsigned long attrs);
+bool dma_direct_need_sync(struct device *dev, dma_addr_t dma_addr);
+int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
+		enum dma_data_direction dir, unsigned long attrs);
+size_t dma_direct_max_mapping_size(struct device *dev);
+
+#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
+    defined(CONFIG_SWIOTLB)
+void dma_direct_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
+		int nents, enum dma_data_direction dir);
+#else
+static inline void dma_direct_sync_sg_for_device(struct device *dev,
+		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
+{
+}
+#endif
+
+#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
+    defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) || \
+    defined(CONFIG_SWIOTLB)
+void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
+		int nents, enum dma_data_direction dir, unsigned long attrs);
+void dma_direct_sync_sg_for_cpu(struct device *dev,
+		struct scatterlist *sgl, int nents, enum dma_data_direction dir);
+#else
+static inline void dma_direct_unmap_sg(struct device *dev,
+		struct scatterlist *sgl, int nents, enum dma_data_direction dir,
+		unsigned long attrs)
+{
+}
+static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
+		struct scatterlist *sgl, int nents, enum dma_data_direction dir)
+{
+}
+#endif
+
+static inline void dma_direct_sync_single_for_device(struct device *dev,
+		dma_addr_t addr, size_t size, enum dma_data_direction dir)
+{
+	phys_addr_t paddr = dma_to_phys(dev, addr);
+
+	if (unlikely(is_swiotlb_buffer(dev, paddr)))
+		swiotlb_sync_single_for_device(dev, paddr, size, dir);
+
+	if (!dev_is_dma_coherent(dev))
+		arch_sync_dma_for_device(paddr, size, dir);
+}
+
+static inline void dma_direct_sync_single_for_cpu(struct device *dev,
+		dma_addr_t addr, size_t size, enum dma_data_direction dir)
+{
+	phys_addr_t paddr = dma_to_phys(dev, addr);
+
+	if (!dev_is_dma_coherent(dev)) {
+		arch_sync_dma_for_cpu(paddr, size, dir);
+		arch_sync_dma_for_cpu_all();
+	}
+
+	if (unlikely(is_swiotlb_buffer(dev, paddr)))
+		swiotlb_sync_single_for_cpu(dev, paddr, size, dir);
+
+	if (dir == DMA_FROM_DEVICE)
+		arch_dma_mark_clean(paddr, size);
+}
+
+static inline dma_addr_t dma_direct_map_page(struct device *dev,
+		struct page *page, unsigned long offset, size_t size,
+		enum dma_data_direction dir, unsigned long attrs)
+{
+	phys_addr_t phys = page_to_phys(page) + offset;
+	dma_addr_t dma_addr = phys_to_dma(dev, phys);
+
+	if (is_swiotlb_force_bounce(dev)) {
+		if (is_pci_p2pdma_page(page))
+			return DMA_MAPPING_ERROR;
+		return swiotlb_map(dev, phys, size, dir, attrs);
+	}
+
+	if (unlikely(!dma_capable(dev, dma_addr, size, true))) {
+		if (is_pci_p2pdma_page(page))
+			return DMA_MAPPING_ERROR;
+		if (is_swiotlb_active(dev))
+			return swiotlb_map(dev, phys, size, dir, attrs);
+
+		dev_WARN_ONCE(dev, 1,
+			     "DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
+			     &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit);
+		return DMA_MAPPING_ERROR;
+	}
+
+	if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		arch_sync_dma_for_device(phys, size, dir);
+	return dma_addr;
+}
+
+static inline void dma_direct_unmap_page(struct device *dev, dma_addr_t addr,
+		size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+	phys_addr_t phys = dma_to_phys(dev, addr);
+
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		dma_direct_sync_single_for_cpu(dev, addr, size, dir);
+
+	if (unlikely(is_swiotlb_buffer(dev, phys)))
+		swiotlb_tbl_unmap_single(dev, phys, size, dir,
+					 attrs | DMA_ATTR_SKIP_CPU_SYNC);
+}
+#endif /* _KERNEL_DMA_DIRECT_H */
diff --git a/kernel/dma/dummy.c b/kernel/dma/dummy.c
new file mode 100644
index 000000000..b492d59ac
--- /dev/null
+++ b/kernel/dma/dummy.c
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Dummy DMA ops that always fail.
+ */
+#include <linux/dma-map-ops.h>
+
+static int dma_dummy_mmap(struct device *dev, struct vm_area_struct *vma,
+		void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		unsigned long attrs)
+{
+	return -ENXIO;
+}
+
+static dma_addr_t dma_dummy_map_page(struct device *dev, struct page *page,
+		unsigned long offset, size_t size, enum dma_data_direction dir,
+		unsigned long attrs)
+{
+	return DMA_MAPPING_ERROR;
+}
+
+static int dma_dummy_map_sg(struct device *dev, struct scatterlist *sgl,
+		int nelems, enum dma_data_direction dir,
+		unsigned long attrs)
+{
+	return -EINVAL;
+}
+
+static int dma_dummy_supported(struct device *hwdev, u64 mask)
+{
+	return 0;
+}
+
+const struct dma_map_ops dma_dummy_ops = {
+	.mmap                   = dma_dummy_mmap,
+	.map_page               = dma_dummy_map_page,
+	.map_sg                 = dma_dummy_map_sg,
+	.dma_supported          = dma_dummy_supported,
+};
diff --git a/kernel/dma/map_benchmark.c b/kernel/dma/map_benchmark.c
new file mode 100644
index 000000000..0520a8f4f
--- /dev/null
+++ b/kernel/dma/map_benchmark.c
@@ -0,0 +1,359 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 HiSilicon Limited.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/map_benchmark.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/timekeeping.h>
+
+struct map_benchmark_data {
+	struct map_benchmark bparam;
+	struct device *dev;
+	struct dentry  *debugfs;
+	enum dma_data_direction dir;
+	atomic64_t sum_map_100ns;
+	atomic64_t sum_unmap_100ns;
+	atomic64_t sum_sq_map;
+	atomic64_t sum_sq_unmap;
+	atomic64_t loops;
+};
+
+static int map_benchmark_thread(void *data)
+{
+	void *buf;
+	dma_addr_t dma_addr;
+	struct map_benchmark_data *map = data;
+	int npages = map->bparam.granule;
+	u64 size = npages * PAGE_SIZE;
+	int ret = 0;
+
+	buf = alloc_pages_exact(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	while (!kthread_should_stop())  {
+		u64 map_100ns, unmap_100ns, map_sq, unmap_sq;
+		ktime_t map_stime, map_etime, unmap_stime, unmap_etime;
+		ktime_t map_delta, unmap_delta;
+
+		/*
+		 * for a non-coherent device, if we don't stain them in the
+		 * cache, this will give an underestimate of the real-world
+		 * overhead of BIDIRECTIONAL or TO_DEVICE mappings;
+		 * 66 means evertything goes well! 66 is lucky.
+		 */
+		if (map->dir != DMA_FROM_DEVICE)
+			memset(buf, 0x66, size);
+
+		map_stime = ktime_get();
+		dma_addr = dma_map_single(map->dev, buf, size, map->dir);
+		if (unlikely(dma_mapping_error(map->dev, dma_addr))) {
+			pr_err("dma_map_single failed on %s\n",
+				dev_name(map->dev));
+			ret = -ENOMEM;
+			goto out;
+		}
+		map_etime = ktime_get();
+		map_delta = ktime_sub(map_etime, map_stime);
+
+		/* Pretend DMA is transmitting */
+		ndelay(map->bparam.dma_trans_ns);
+
+		unmap_stime = ktime_get();
+		dma_unmap_single(map->dev, dma_addr, size, map->dir);
+		unmap_etime = ktime_get();
+		unmap_delta = ktime_sub(unmap_etime, unmap_stime);
+
+		/* calculate sum and sum of squares */
+
+		map_100ns = div64_ul(map_delta,  100);
+		unmap_100ns = div64_ul(unmap_delta, 100);
+		map_sq = map_100ns * map_100ns;
+		unmap_sq = unmap_100ns * unmap_100ns;
+
+		atomic64_add(map_100ns, &map->sum_map_100ns);
+		atomic64_add(unmap_100ns, &map->sum_unmap_100ns);
+		atomic64_add(map_sq, &map->sum_sq_map);
+		atomic64_add(unmap_sq, &map->sum_sq_unmap);
+		atomic64_inc(&map->loops);
+	}
+
+out:
+	free_pages_exact(buf, size);
+	return ret;
+}
+
+static int do_map_benchmark(struct map_benchmark_data *map)
+{
+	struct task_struct **tsk;
+	int threads = map->bparam.threads;
+	int node = map->bparam.node;
+	const cpumask_t *cpu_mask = cpumask_of_node(node);
+	u64 loops;
+	int ret = 0;
+	int i;
+
+	tsk = kmalloc_array(threads, sizeof(*tsk), GFP_KERNEL);
+	if (!tsk)
+		return -ENOMEM;
+
+	get_device(map->dev);
+
+	for (i = 0; i < threads; i++) {
+		tsk[i] = kthread_create_on_node(map_benchmark_thread, map,
+				map->bparam.node, "dma-map-benchmark/%d", i);
+		if (IS_ERR(tsk[i])) {
+			pr_err("create dma_map thread failed\n");
+			ret = PTR_ERR(tsk[i]);
+			goto out;
+		}
+
+		if (node != NUMA_NO_NODE)
+			kthread_bind_mask(tsk[i], cpu_mask);
+	}
+
+	/* clear the old value in the previous benchmark */
+	atomic64_set(&map->sum_map_100ns, 0);
+	atomic64_set(&map->sum_unmap_100ns, 0);
+	atomic64_set(&map->sum_sq_map, 0);
+	atomic64_set(&map->sum_sq_unmap, 0);
+	atomic64_set(&map->loops, 0);
+
+	for (i = 0; i < threads; i++) {
+		get_task_struct(tsk[i]);
+		wake_up_process(tsk[i]);
+	}
+
+	msleep_interruptible(map->bparam.seconds * 1000);
+
+	/* wait for the completion of benchmark threads */
+	for (i = 0; i < threads; i++) {
+		ret = kthread_stop(tsk[i]);
+		if (ret)
+			goto out;
+	}
+
+	loops = atomic64_read(&map->loops);
+	if (likely(loops > 0)) {
+		u64 map_variance, unmap_variance;
+		u64 sum_map = atomic64_read(&map->sum_map_100ns);
+		u64 sum_unmap = atomic64_read(&map->sum_unmap_100ns);
+		u64 sum_sq_map = atomic64_read(&map->sum_sq_map);
+		u64 sum_sq_unmap = atomic64_read(&map->sum_sq_unmap);
+
+		/* average latency */
+		map->bparam.avg_map_100ns = div64_u64(sum_map, loops);
+		map->bparam.avg_unmap_100ns = div64_u64(sum_unmap, loops);
+
+		/* standard deviation of latency */
+		map_variance = div64_u64(sum_sq_map, loops) -
+				map->bparam.avg_map_100ns *
+				map->bparam.avg_map_100ns;
+		unmap_variance = div64_u64(sum_sq_unmap, loops) -
+				map->bparam.avg_unmap_100ns *
+				map->bparam.avg_unmap_100ns;
+		map->bparam.map_stddev = int_sqrt64(map_variance);
+		map->bparam.unmap_stddev = int_sqrt64(unmap_variance);
+	}
+
+out:
+	for (i = 0; i < threads; i++)
+		put_task_struct(tsk[i]);
+	put_device(map->dev);
+	kfree(tsk);
+	return ret;
+}
+
+static long map_benchmark_ioctl(struct file *file, unsigned int cmd,
+		unsigned long arg)
+{
+	struct map_benchmark_data *map = file->private_data;
+	void __user *argp = (void __user *)arg;
+	u64 old_dma_mask;
+	int ret;
+
+	if (copy_from_user(&map->bparam, argp, sizeof(map->bparam)))
+		return -EFAULT;
+
+	switch (cmd) {
+	case DMA_MAP_BENCHMARK:
+		if (map->bparam.threads == 0 ||
+		    map->bparam.threads > DMA_MAP_MAX_THREADS) {
+			pr_err("invalid thread number\n");
+			return -EINVAL;
+		}
+
+		if (map->bparam.seconds == 0 ||
+		    map->bparam.seconds > DMA_MAP_MAX_SECONDS) {
+			pr_err("invalid duration seconds\n");
+			return -EINVAL;
+		}
+
+		if (map->bparam.dma_trans_ns > DMA_MAP_MAX_TRANS_DELAY) {
+			pr_err("invalid transmission delay\n");
+			return -EINVAL;
+		}
+
+		if (map->bparam.node != NUMA_NO_NODE &&
+		    !node_possible(map->bparam.node)) {
+			pr_err("invalid numa node\n");
+			return -EINVAL;
+		}
+
+		if (map->bparam.granule < 1 || map->bparam.granule > 1024) {
+			pr_err("invalid granule size\n");
+			return -EINVAL;
+		}
+
+		switch (map->bparam.dma_dir) {
+		case DMA_MAP_BIDIRECTIONAL:
+			map->dir = DMA_BIDIRECTIONAL;
+			break;
+		case DMA_MAP_FROM_DEVICE:
+			map->dir = DMA_FROM_DEVICE;
+			break;
+		case DMA_MAP_TO_DEVICE:
+			map->dir = DMA_TO_DEVICE;
+			break;
+		default:
+			pr_err("invalid DMA direction\n");
+			return -EINVAL;
+		}
+
+		old_dma_mask = dma_get_mask(map->dev);
+
+		ret = dma_set_mask(map->dev,
+				   DMA_BIT_MASK(map->bparam.dma_bits));
+		if (ret) {
+			pr_err("failed to set dma_mask on device %s\n",
+				dev_name(map->dev));
+			return -EINVAL;
+		}
+
+		ret = do_map_benchmark(map);
+
+		/*
+		 * restore the original dma_mask as many devices' dma_mask are
+		 * set by architectures, acpi, busses. When we bind them back
+		 * to their original drivers, those drivers shouldn't see
+		 * dma_mask changed by benchmark
+		 */
+		dma_set_mask(map->dev, old_dma_mask);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (copy_to_user(argp, &map->bparam, sizeof(map->bparam)))
+		return -EFAULT;
+
+	return ret;
+}
+
+static const struct file_operations map_benchmark_fops = {
+	.open			= simple_open,
+	.unlocked_ioctl		= map_benchmark_ioctl,
+};
+
+static void map_benchmark_remove_debugfs(void *data)
+{
+	struct map_benchmark_data *map = (struct map_benchmark_data *)data;
+
+	debugfs_remove(map->debugfs);
+}
+
+static int __map_benchmark_probe(struct device *dev)
+{
+	struct dentry *entry;
+	struct map_benchmark_data *map;
+	int ret;
+
+	map = devm_kzalloc(dev, sizeof(*map), GFP_KERNEL);
+	if (!map)
+		return -ENOMEM;
+	map->dev = dev;
+
+	ret = devm_add_action(dev, map_benchmark_remove_debugfs, map);
+	if (ret) {
+		pr_err("Can't add debugfs remove action\n");
+		return ret;
+	}
+
+	/*
+	 * we only permit a device bound with this driver, 2nd probe
+	 * will fail
+	 */
+	entry = debugfs_create_file("dma_map_benchmark", 0600, NULL, map,
+			&map_benchmark_fops);
+	if (IS_ERR(entry))
+		return PTR_ERR(entry);
+	map->debugfs = entry;
+
+	return 0;
+}
+
+static int map_benchmark_platform_probe(struct platform_device *pdev)
+{
+	return __map_benchmark_probe(&pdev->dev);
+}
+
+static struct platform_driver map_benchmark_platform_driver = {
+	.driver		= {
+		.name	= "dma_map_benchmark",
+	},
+	.probe = map_benchmark_platform_probe,
+};
+
+static int
+map_benchmark_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	return __map_benchmark_probe(&pdev->dev);
+}
+
+static struct pci_driver map_benchmark_pci_driver = {
+	.name	= "dma_map_benchmark",
+	.probe	= map_benchmark_pci_probe,
+};
+
+static int __init map_benchmark_init(void)
+{
+	int ret;
+
+	ret = pci_register_driver(&map_benchmark_pci_driver);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&map_benchmark_platform_driver);
+	if (ret) {
+		pci_unregister_driver(&map_benchmark_pci_driver);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit map_benchmark_cleanup(void)
+{
+	platform_driver_unregister(&map_benchmark_platform_driver);
+	pci_unregister_driver(&map_benchmark_pci_driver);
+}
+
+module_init(map_benchmark_init);
+module_exit(map_benchmark_cleanup);
+
+MODULE_AUTHOR("Barry Song <song.bao.hua@hisilicon.com>");
+MODULE_DESCRIPTION("dma_map benchmark driver");
+MODULE_LICENSE("GPL");
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
new file mode 100644
index 000000000..33437d620
--- /dev/null
+++ b/kernel/dma/mapping.c
@@ -0,0 +1,831 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * arch-independent dma-mapping routines
+ *
+ * Copyright (c) 2006  SUSE Linux Products GmbH
+ * Copyright (c) 2006  Tejun Heo <teheo@suse.de>
+ */
+#include <linux/memblock.h> /* for max_pfn */
+#include <linux/acpi.h>
+#include <linux/dma-map-ops.h>
+#include <linux/export.h>
+#include <linux/gfp.h>
+#include <linux/kmsan.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include "debug.h"
+#include "direct.h"
+
+bool dma_default_coherent;
+
+/*
+ * Managed DMA API
+ */
+struct dma_devres {
+	size_t		size;
+	void		*vaddr;
+	dma_addr_t	dma_handle;
+	unsigned long	attrs;
+};
+
+static void dmam_release(struct device *dev, void *res)
+{
+	struct dma_devres *this = res;
+
+	dma_free_attrs(dev, this->size, this->vaddr, this->dma_handle,
+			this->attrs);
+}
+
+static int dmam_match(struct device *dev, void *res, void *match_data)
+{
+	struct dma_devres *this = res, *match = match_data;
+
+	if (this->vaddr == match->vaddr) {
+		WARN_ON(this->size != match->size ||
+			this->dma_handle != match->dma_handle);
+		return 1;
+	}
+	return 0;
+}
+
+/**
+ * dmam_free_coherent - Managed dma_free_coherent()
+ * @dev: Device to free coherent memory for
+ * @size: Size of allocation
+ * @vaddr: Virtual address of the memory to free
+ * @dma_handle: DMA handle of the memory to free
+ *
+ * Managed dma_free_coherent().
+ */
+void dmam_free_coherent(struct device *dev, size_t size, void *vaddr,
+			dma_addr_t dma_handle)
+{
+	struct dma_devres match_data = { size, vaddr, dma_handle };
+
+	dma_free_coherent(dev, size, vaddr, dma_handle);
+	WARN_ON(devres_destroy(dev, dmam_release, dmam_match, &match_data));
+}
+EXPORT_SYMBOL(dmam_free_coherent);
+
+/**
+ * dmam_alloc_attrs - Managed dma_alloc_attrs()
+ * @dev: Device to allocate non_coherent memory for
+ * @size: Size of allocation
+ * @dma_handle: Out argument for allocated DMA handle
+ * @gfp: Allocation flags
+ * @attrs: Flags in the DMA_ATTR_* namespace.
+ *
+ * Managed dma_alloc_attrs().  Memory allocated using this function will be
+ * automatically released on driver detach.
+ *
+ * RETURNS:
+ * Pointer to allocated memory on success, NULL on failure.
+ */
+void *dmam_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
+		gfp_t gfp, unsigned long attrs)
+{
+	struct dma_devres *dr;
+	void *vaddr;
+
+	dr = devres_alloc(dmam_release, sizeof(*dr), gfp);
+	if (!dr)
+		return NULL;
+
+	vaddr = dma_alloc_attrs(dev, size, dma_handle, gfp, attrs);
+	if (!vaddr) {
+		devres_free(dr);
+		return NULL;
+	}
+
+	dr->vaddr = vaddr;
+	dr->dma_handle = *dma_handle;
+	dr->size = size;
+	dr->attrs = attrs;
+
+	devres_add(dev, dr);
+
+	return vaddr;
+}
+EXPORT_SYMBOL(dmam_alloc_attrs);
+
+static bool dma_go_direct(struct device *dev, dma_addr_t mask,
+		const struct dma_map_ops *ops)
+{
+	if (likely(!ops))
+		return true;
+#ifdef CONFIG_DMA_OPS_BYPASS
+	if (dev->dma_ops_bypass)
+		return min_not_zero(mask, dev->bus_dma_limit) >=
+			    dma_direct_get_required_mask(dev);
+#endif
+	return false;
+}
+
+
+/*
+ * Check if the devices uses a direct mapping for streaming DMA operations.
+ * This allows IOMMU drivers to set a bypass mode if the DMA mask is large
+ * enough.
+ */
+static inline bool dma_alloc_direct(struct device *dev,
+		const struct dma_map_ops *ops)
+{
+	return dma_go_direct(dev, dev->coherent_dma_mask, ops);
+}
+
+static inline bool dma_map_direct(struct device *dev,
+		const struct dma_map_ops *ops)
+{
+	return dma_go_direct(dev, *dev->dma_mask, ops);
+}
+
+dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page,
+		size_t offset, size_t size, enum dma_data_direction dir,
+		unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	dma_addr_t addr;
+
+	BUG_ON(!valid_dma_direction(dir));
+
+	if (WARN_ON_ONCE(!dev->dma_mask))
+		return DMA_MAPPING_ERROR;
+
+	if (dma_map_direct(dev, ops) ||
+	    arch_dma_map_page_direct(dev, page_to_phys(page) + offset + size))
+		addr = dma_direct_map_page(dev, page, offset, size, dir, attrs);
+	else
+		addr = ops->map_page(dev, page, offset, size, dir, attrs);
+	kmsan_handle_dma(page, offset, size, dir);
+	debug_dma_map_page(dev, page, offset, size, dir, addr, attrs);
+
+	return addr;
+}
+EXPORT_SYMBOL(dma_map_page_attrs);
+
+void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr, size_t size,
+		enum dma_data_direction dir, unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	BUG_ON(!valid_dma_direction(dir));
+	if (dma_map_direct(dev, ops) ||
+	    arch_dma_unmap_page_direct(dev, addr + size))
+		dma_direct_unmap_page(dev, addr, size, dir, attrs);
+	else if (ops->unmap_page)
+		ops->unmap_page(dev, addr, size, dir, attrs);
+	debug_dma_unmap_page(dev, addr, size, dir);
+}
+EXPORT_SYMBOL(dma_unmap_page_attrs);
+
+static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
+	 int nents, enum dma_data_direction dir, unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	int ents;
+
+	BUG_ON(!valid_dma_direction(dir));
+
+	if (WARN_ON_ONCE(!dev->dma_mask))
+		return 0;
+
+	if (dma_map_direct(dev, ops) ||
+	    arch_dma_map_sg_direct(dev, sg, nents))
+		ents = dma_direct_map_sg(dev, sg, nents, dir, attrs);
+	else
+		ents = ops->map_sg(dev, sg, nents, dir, attrs);
+
+	if (ents > 0) {
+		kmsan_handle_dma_sg(sg, nents, dir);
+		debug_dma_map_sg(dev, sg, nents, ents, dir, attrs);
+	} else if (WARN_ON_ONCE(ents != -EINVAL && ents != -ENOMEM &&
+				ents != -EIO && ents != -EREMOTEIO)) {
+		return -EIO;
+	}
+
+	return ents;
+}
+
+/**
+ * dma_map_sg_attrs - Map the given buffer for DMA
+ * @dev:	The device for which to perform the DMA operation
+ * @sg:		The sg_table object describing the buffer
+ * @nents:	Number of entries to map
+ * @dir:	DMA direction
+ * @attrs:	Optional DMA attributes for the map operation
+ *
+ * Maps a buffer described by a scatterlist passed in the sg argument with
+ * nents segments for the @dir DMA operation by the @dev device.
+ *
+ * Returns the number of mapped entries (which can be less than nents)
+ * on success. Zero is returned for any error.
+ *
+ * dma_unmap_sg_attrs() should be used to unmap the buffer with the
+ * original sg and original nents (not the value returned by this funciton).
+ */
+unsigned int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
+		    int nents, enum dma_data_direction dir, unsigned long attrs)
+{
+	int ret;
+
+	ret = __dma_map_sg_attrs(dev, sg, nents, dir, attrs);
+	if (ret < 0)
+		return 0;
+	return ret;
+}
+EXPORT_SYMBOL(dma_map_sg_attrs);
+
+/**
+ * dma_map_sgtable - Map the given buffer for DMA
+ * @dev:	The device for which to perform the DMA operation
+ * @sgt:	The sg_table object describing the buffer
+ * @dir:	DMA direction
+ * @attrs:	Optional DMA attributes for the map operation
+ *
+ * Maps a buffer described by a scatterlist stored in the given sg_table
+ * object for the @dir DMA operation by the @dev device. After success, the
+ * ownership for the buffer is transferred to the DMA domain.  One has to
+ * call dma_sync_sgtable_for_cpu() or dma_unmap_sgtable() to move the
+ * ownership of the buffer back to the CPU domain before touching the
+ * buffer by the CPU.
+ *
+ * Returns 0 on success or a negative error code on error. The following
+ * error codes are supported with the given meaning:
+ *
+ *   -EINVAL		An invalid argument, unaligned access or other error
+ *			in usage. Will not succeed if retried.
+ *   -ENOMEM		Insufficient resources (like memory or IOVA space) to
+ *			complete the mapping. Should succeed if retried later.
+ *   -EIO		Legacy error code with an unknown meaning. eg. this is
+ *			returned if a lower level call returned
+ *			DMA_MAPPING_ERROR.
+ *   -EREMOTEIO		The DMA device cannot access P2PDMA memory specified
+ *			in the sg_table. This will not succeed if retried.
+ */
+int dma_map_sgtable(struct device *dev, struct sg_table *sgt,
+		    enum dma_data_direction dir, unsigned long attrs)
+{
+	int nents;
+
+	nents = __dma_map_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs);
+	if (nents < 0)
+		return nents;
+	sgt->nents = nents;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dma_map_sgtable);
+
+void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
+				      int nents, enum dma_data_direction dir,
+				      unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	BUG_ON(!valid_dma_direction(dir));
+	debug_dma_unmap_sg(dev, sg, nents, dir);
+	if (dma_map_direct(dev, ops) ||
+	    arch_dma_unmap_sg_direct(dev, sg, nents))
+		dma_direct_unmap_sg(dev, sg, nents, dir, attrs);
+	else if (ops->unmap_sg)
+		ops->unmap_sg(dev, sg, nents, dir, attrs);
+}
+EXPORT_SYMBOL(dma_unmap_sg_attrs);
+
+dma_addr_t dma_map_resource(struct device *dev, phys_addr_t phys_addr,
+		size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	dma_addr_t addr = DMA_MAPPING_ERROR;
+
+	BUG_ON(!valid_dma_direction(dir));
+
+	if (WARN_ON_ONCE(!dev->dma_mask))
+		return DMA_MAPPING_ERROR;
+
+	if (dma_map_direct(dev, ops))
+		addr = dma_direct_map_resource(dev, phys_addr, size, dir, attrs);
+	else if (ops->map_resource)
+		addr = ops->map_resource(dev, phys_addr, size, dir, attrs);
+
+	debug_dma_map_resource(dev, phys_addr, size, dir, addr, attrs);
+	return addr;
+}
+EXPORT_SYMBOL(dma_map_resource);
+
+void dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
+		enum dma_data_direction dir, unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	BUG_ON(!valid_dma_direction(dir));
+	if (!dma_map_direct(dev, ops) && ops->unmap_resource)
+		ops->unmap_resource(dev, addr, size, dir, attrs);
+	debug_dma_unmap_resource(dev, addr, size, dir);
+}
+EXPORT_SYMBOL(dma_unmap_resource);
+
+void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
+		enum dma_data_direction dir)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	BUG_ON(!valid_dma_direction(dir));
+	if (dma_map_direct(dev, ops))
+		dma_direct_sync_single_for_cpu(dev, addr, size, dir);
+	else if (ops->sync_single_for_cpu)
+		ops->sync_single_for_cpu(dev, addr, size, dir);
+	debug_dma_sync_single_for_cpu(dev, addr, size, dir);
+}
+EXPORT_SYMBOL(dma_sync_single_for_cpu);
+
+void dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
+		size_t size, enum dma_data_direction dir)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	BUG_ON(!valid_dma_direction(dir));
+	if (dma_map_direct(dev, ops))
+		dma_direct_sync_single_for_device(dev, addr, size, dir);
+	else if (ops->sync_single_for_device)
+		ops->sync_single_for_device(dev, addr, size, dir);
+	debug_dma_sync_single_for_device(dev, addr, size, dir);
+}
+EXPORT_SYMBOL(dma_sync_single_for_device);
+
+void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
+		    int nelems, enum dma_data_direction dir)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	BUG_ON(!valid_dma_direction(dir));
+	if (dma_map_direct(dev, ops))
+		dma_direct_sync_sg_for_cpu(dev, sg, nelems, dir);
+	else if (ops->sync_sg_for_cpu)
+		ops->sync_sg_for_cpu(dev, sg, nelems, dir);
+	debug_dma_sync_sg_for_cpu(dev, sg, nelems, dir);
+}
+EXPORT_SYMBOL(dma_sync_sg_for_cpu);
+
+void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
+		       int nelems, enum dma_data_direction dir)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	BUG_ON(!valid_dma_direction(dir));
+	if (dma_map_direct(dev, ops))
+		dma_direct_sync_sg_for_device(dev, sg, nelems, dir);
+	else if (ops->sync_sg_for_device)
+		ops->sync_sg_for_device(dev, sg, nelems, dir);
+	debug_dma_sync_sg_for_device(dev, sg, nelems, dir);
+}
+EXPORT_SYMBOL(dma_sync_sg_for_device);
+
+/*
+ * The whole dma_get_sgtable() idea is fundamentally unsafe - it seems
+ * that the intention is to allow exporting memory allocated via the
+ * coherent DMA APIs through the dma_buf API, which only accepts a
+ * scattertable.  This presents a couple of problems:
+ * 1. Not all memory allocated via the coherent DMA APIs is backed by
+ *    a struct page
+ * 2. Passing coherent DMA memory into the streaming APIs is not allowed
+ *    as we will try to flush the memory through a different alias to that
+ *    actually being used (and the flushes are redundant.)
+ */
+int dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt,
+		void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (dma_alloc_direct(dev, ops))
+		return dma_direct_get_sgtable(dev, sgt, cpu_addr, dma_addr,
+				size, attrs);
+	if (!ops->get_sgtable)
+		return -ENXIO;
+	return ops->get_sgtable(dev, sgt, cpu_addr, dma_addr, size, attrs);
+}
+EXPORT_SYMBOL(dma_get_sgtable_attrs);
+
+#ifdef CONFIG_MMU
+/*
+ * Return the page attributes used for mapping dma_alloc_* memory, either in
+ * kernel space if remapping is needed, or to userspace through dma_mmap_*.
+ */
+pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs)
+{
+	if (dev_is_dma_coherent(dev))
+		return prot;
+#ifdef CONFIG_ARCH_HAS_DMA_WRITE_COMBINE
+	if (attrs & DMA_ATTR_WRITE_COMBINE)
+		return pgprot_writecombine(prot);
+#endif
+	return pgprot_dmacoherent(prot);
+}
+#endif /* CONFIG_MMU */
+
+/**
+ * dma_can_mmap - check if a given device supports dma_mmap_*
+ * @dev: device to check
+ *
+ * Returns %true if @dev supports dma_mmap_coherent() and dma_mmap_attrs() to
+ * map DMA allocations to userspace.
+ */
+bool dma_can_mmap(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (dma_alloc_direct(dev, ops))
+		return dma_direct_can_mmap(dev);
+	return ops->mmap != NULL;
+}
+EXPORT_SYMBOL_GPL(dma_can_mmap);
+
+/**
+ * dma_mmap_attrs - map a coherent DMA allocation into user space
+ * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
+ * @vma: vm_area_struct describing requested user mapping
+ * @cpu_addr: kernel CPU-view address returned from dma_alloc_attrs
+ * @dma_addr: device-view address returned from dma_alloc_attrs
+ * @size: size of memory originally requested in dma_alloc_attrs
+ * @attrs: attributes of mapping properties requested in dma_alloc_attrs
+ *
+ * Map a coherent DMA buffer previously allocated by dma_alloc_attrs into user
+ * space.  The coherent DMA buffer must not be freed by the driver until the
+ * user space mapping has been released.
+ */
+int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
+		void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (dma_alloc_direct(dev, ops))
+		return dma_direct_mmap(dev, vma, cpu_addr, dma_addr, size,
+				attrs);
+	if (!ops->mmap)
+		return -ENXIO;
+	return ops->mmap(dev, vma, cpu_addr, dma_addr, size, attrs);
+}
+EXPORT_SYMBOL(dma_mmap_attrs);
+
+u64 dma_get_required_mask(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (dma_alloc_direct(dev, ops))
+		return dma_direct_get_required_mask(dev);
+	if (ops->get_required_mask)
+		return ops->get_required_mask(dev);
+
+	/*
+	 * We require every DMA ops implementation to at least support a 32-bit
+	 * DMA mask (and use bounce buffering if that isn't supported in
+	 * hardware).  As the direct mapping code has its own routine to
+	 * actually report an optimal mask we default to 32-bit here as that
+	 * is the right thing for most IOMMUs, and at least not actively
+	 * harmful in general.
+	 */
+	return DMA_BIT_MASK(32);
+}
+EXPORT_SYMBOL_GPL(dma_get_required_mask);
+
+void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
+		gfp_t flag, unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	void *cpu_addr;
+
+	WARN_ON_ONCE(!dev->coherent_dma_mask);
+
+	if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr))
+		return cpu_addr;
+
+	/* let the implementation decide on the zone to allocate from: */
+	flag &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM);
+
+	if (dma_alloc_direct(dev, ops))
+		cpu_addr = dma_direct_alloc(dev, size, dma_handle, flag, attrs);
+	else if (ops->alloc)
+		cpu_addr = ops->alloc(dev, size, dma_handle, flag, attrs);
+	else
+		return NULL;
+
+	debug_dma_alloc_coherent(dev, size, *dma_handle, cpu_addr, attrs);
+	return cpu_addr;
+}
+EXPORT_SYMBOL(dma_alloc_attrs);
+
+void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
+		dma_addr_t dma_handle, unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (dma_release_from_dev_coherent(dev, get_order(size), cpu_addr))
+		return;
+	/*
+	 * On non-coherent platforms which implement DMA-coherent buffers via
+	 * non-cacheable remaps, ops->free() may call vunmap(). Thus getting
+	 * this far in IRQ context is a) at risk of a BUG_ON() or trying to
+	 * sleep on some machines, and b) an indication that the driver is
+	 * probably misusing the coherent API anyway.
+	 */
+	WARN_ON(irqs_disabled());
+
+	if (!cpu_addr)
+		return;
+
+	debug_dma_free_coherent(dev, size, cpu_addr, dma_handle);
+	if (dma_alloc_direct(dev, ops))
+		dma_direct_free(dev, size, cpu_addr, dma_handle, attrs);
+	else if (ops->free)
+		ops->free(dev, size, cpu_addr, dma_handle, attrs);
+}
+EXPORT_SYMBOL(dma_free_attrs);
+
+static struct page *__dma_alloc_pages(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (WARN_ON_ONCE(!dev->coherent_dma_mask))
+		return NULL;
+	if (WARN_ON_ONCE(gfp & (__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM)))
+		return NULL;
+
+	size = PAGE_ALIGN(size);
+	if (dma_alloc_direct(dev, ops))
+		return dma_direct_alloc_pages(dev, size, dma_handle, dir, gfp);
+	if (!ops->alloc_pages)
+		return NULL;
+	return ops->alloc_pages(dev, size, dma_handle, dir, gfp);
+}
+
+struct page *dma_alloc_pages(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
+{
+	struct page *page = __dma_alloc_pages(dev, size, dma_handle, dir, gfp);
+
+	if (page)
+		debug_dma_map_page(dev, page, 0, size, dir, *dma_handle, 0);
+	return page;
+}
+EXPORT_SYMBOL_GPL(dma_alloc_pages);
+
+static void __dma_free_pages(struct device *dev, size_t size, struct page *page,
+		dma_addr_t dma_handle, enum dma_data_direction dir)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	size = PAGE_ALIGN(size);
+	if (dma_alloc_direct(dev, ops))
+		dma_direct_free_pages(dev, size, page, dma_handle, dir);
+	else if (ops->free_pages)
+		ops->free_pages(dev, size, page, dma_handle, dir);
+}
+
+void dma_free_pages(struct device *dev, size_t size, struct page *page,
+		dma_addr_t dma_handle, enum dma_data_direction dir)
+{
+	debug_dma_unmap_page(dev, dma_handle, size, dir);
+	__dma_free_pages(dev, size, page, dma_handle, dir);
+}
+EXPORT_SYMBOL_GPL(dma_free_pages);
+
+int dma_mmap_pages(struct device *dev, struct vm_area_struct *vma,
+		size_t size, struct page *page)
+{
+	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+	if (vma->vm_pgoff >= count || vma_pages(vma) > count - vma->vm_pgoff)
+		return -ENXIO;
+	return remap_pfn_range(vma, vma->vm_start,
+			       page_to_pfn(page) + vma->vm_pgoff,
+			       vma_pages(vma) << PAGE_SHIFT, vma->vm_page_prot);
+}
+EXPORT_SYMBOL_GPL(dma_mmap_pages);
+
+static struct sg_table *alloc_single_sgt(struct device *dev, size_t size,
+		enum dma_data_direction dir, gfp_t gfp)
+{
+	struct sg_table *sgt;
+	struct page *page;
+
+	sgt = kmalloc(sizeof(*sgt), gfp);
+	if (!sgt)
+		return NULL;
+	if (sg_alloc_table(sgt, 1, gfp))
+		goto out_free_sgt;
+	page = __dma_alloc_pages(dev, size, &sgt->sgl->dma_address, dir, gfp);
+	if (!page)
+		goto out_free_table;
+	sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
+	sg_dma_len(sgt->sgl) = sgt->sgl->length;
+	return sgt;
+out_free_table:
+	sg_free_table(sgt);
+out_free_sgt:
+	kfree(sgt);
+	return NULL;
+}
+
+struct sg_table *dma_alloc_noncontiguous(struct device *dev, size_t size,
+		enum dma_data_direction dir, gfp_t gfp, unsigned long attrs)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	struct sg_table *sgt;
+
+	if (WARN_ON_ONCE(attrs & ~DMA_ATTR_ALLOC_SINGLE_PAGES))
+		return NULL;
+
+	if (ops && ops->alloc_noncontiguous)
+		sgt = ops->alloc_noncontiguous(dev, size, dir, gfp, attrs);
+	else
+		sgt = alloc_single_sgt(dev, size, dir, gfp);
+
+	if (sgt) {
+		sgt->nents = 1;
+		debug_dma_map_sg(dev, sgt->sgl, sgt->orig_nents, 1, dir, attrs);
+	}
+	return sgt;
+}
+EXPORT_SYMBOL_GPL(dma_alloc_noncontiguous);
+
+static void free_single_sgt(struct device *dev, size_t size,
+		struct sg_table *sgt, enum dma_data_direction dir)
+{
+	__dma_free_pages(dev, size, sg_page(sgt->sgl), sgt->sgl->dma_address,
+			 dir);
+	sg_free_table(sgt);
+	kfree(sgt);
+}
+
+void dma_free_noncontiguous(struct device *dev, size_t size,
+		struct sg_table *sgt, enum dma_data_direction dir)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	debug_dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
+	if (ops && ops->free_noncontiguous)
+		ops->free_noncontiguous(dev, size, sgt, dir);
+	else
+		free_single_sgt(dev, size, sgt, dir);
+}
+EXPORT_SYMBOL_GPL(dma_free_noncontiguous);
+
+void *dma_vmap_noncontiguous(struct device *dev, size_t size,
+		struct sg_table *sgt)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+	if (ops && ops->alloc_noncontiguous)
+		return vmap(sgt_handle(sgt)->pages, count, VM_MAP, PAGE_KERNEL);
+	return page_address(sg_page(sgt->sgl));
+}
+EXPORT_SYMBOL_GPL(dma_vmap_noncontiguous);
+
+void dma_vunmap_noncontiguous(struct device *dev, void *vaddr)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (ops && ops->alloc_noncontiguous)
+		vunmap(vaddr);
+}
+EXPORT_SYMBOL_GPL(dma_vunmap_noncontiguous);
+
+int dma_mmap_noncontiguous(struct device *dev, struct vm_area_struct *vma,
+		size_t size, struct sg_table *sgt)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (ops && ops->alloc_noncontiguous) {
+		unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+		if (vma->vm_pgoff >= count ||
+		    vma_pages(vma) > count - vma->vm_pgoff)
+			return -ENXIO;
+		return vm_map_pages(vma, sgt_handle(sgt)->pages, count);
+	}
+	return dma_mmap_pages(dev, vma, size, sg_page(sgt->sgl));
+}
+EXPORT_SYMBOL_GPL(dma_mmap_noncontiguous);
+
+static int dma_supported(struct device *dev, u64 mask)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	/*
+	 * ->dma_supported sets the bypass flag, so we must always call
+	 * into the method here unless the device is truly direct mapped.
+	 */
+	if (!ops)
+		return dma_direct_supported(dev, mask);
+	if (!ops->dma_supported)
+		return 1;
+	return ops->dma_supported(dev, mask);
+}
+
+bool dma_pci_p2pdma_supported(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	/* if ops is not set, dma direct will be used which supports P2PDMA */
+	if (!ops)
+		return true;
+
+	/*
+	 * Note: dma_ops_bypass is not checked here because P2PDMA should
+	 * not be used with dma mapping ops that do not have support even
+	 * if the specific device is bypassing them.
+	 */
+
+	return ops->flags & DMA_F_PCI_P2PDMA_SUPPORTED;
+}
+EXPORT_SYMBOL_GPL(dma_pci_p2pdma_supported);
+
+#ifdef CONFIG_ARCH_HAS_DMA_SET_MASK
+void arch_dma_set_mask(struct device *dev, u64 mask);
+#else
+#define arch_dma_set_mask(dev, mask)	do { } while (0)
+#endif
+
+int dma_set_mask(struct device *dev, u64 mask)
+{
+	/*
+	 * Truncate the mask to the actually supported dma_addr_t width to
+	 * avoid generating unsupportable addresses.
+	 */
+	mask = (dma_addr_t)mask;
+
+	if (!dev->dma_mask || !dma_supported(dev, mask))
+		return -EIO;
+
+	arch_dma_set_mask(dev, mask);
+	*dev->dma_mask = mask;
+	return 0;
+}
+EXPORT_SYMBOL(dma_set_mask);
+
+int dma_set_coherent_mask(struct device *dev, u64 mask)
+{
+	/*
+	 * Truncate the mask to the actually supported dma_addr_t width to
+	 * avoid generating unsupportable addresses.
+	 */
+	mask = (dma_addr_t)mask;
+
+	if (!dma_supported(dev, mask))
+		return -EIO;
+
+	dev->coherent_dma_mask = mask;
+	return 0;
+}
+EXPORT_SYMBOL(dma_set_coherent_mask);
+
+size_t dma_max_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (dma_map_direct(dev, ops))
+		size = dma_direct_max_mapping_size(dev);
+	else if (ops && ops->max_mapping_size)
+		size = ops->max_mapping_size(dev);
+
+	return size;
+}
+EXPORT_SYMBOL_GPL(dma_max_mapping_size);
+
+size_t dma_opt_mapping_size(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	size_t size = SIZE_MAX;
+
+	if (ops && ops->opt_mapping_size)
+		size = ops->opt_mapping_size();
+
+	return min(dma_max_mapping_size(dev), size);
+}
+EXPORT_SYMBOL_GPL(dma_opt_mapping_size);
+
+bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (dma_map_direct(dev, ops))
+		return dma_direct_need_sync(dev, dma_addr);
+	return ops->sync_single_for_cpu || ops->sync_single_for_device;
+}
+EXPORT_SYMBOL_GPL(dma_need_sync);
+
+unsigned long dma_get_merge_boundary(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (!ops || !ops->get_merge_boundary)
+		return 0;	/* can't merge */
+
+	return ops->get_merge_boundary(dev);
+}
+EXPORT_SYMBOL_GPL(dma_get_merge_boundary);
diff --git a/kernel/dma/ops_helpers.c b/kernel/dma/ops_helpers.c
new file mode 100644
index 000000000..af4a6ef48
--- /dev/null
+++ b/kernel/dma/ops_helpers.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Helpers for DMA ops implementations.  These generally rely on the fact that
+ * the allocated memory contains normal pages in the direct kernel mapping.
+ */
+#include <linux/dma-map-ops.h>
+
+static struct page *dma_common_vaddr_to_page(void *cpu_addr)
+{
+	if (is_vmalloc_addr(cpu_addr))
+		return vmalloc_to_page(cpu_addr);
+	return virt_to_page(cpu_addr);
+}
+
+/*
+ * Create scatter-list for the already allocated DMA buffer.
+ */
+int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
+		 void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		 unsigned long attrs)
+{
+	struct page *page = dma_common_vaddr_to_page(cpu_addr);
+	int ret;
+
+	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
+	if (!ret)
+		sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
+	return ret;
+}
+
+/*
+ * Create userspace mapping for the DMA-coherent memory.
+ */
+int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
+		void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		unsigned long attrs)
+{
+#ifdef CONFIG_MMU
+	unsigned long user_count = vma_pages(vma);
+	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	unsigned long off = vma->vm_pgoff;
+	struct page *page = dma_common_vaddr_to_page(cpu_addr);
+	int ret = -ENXIO;
+
+	vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
+
+	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
+		return ret;
+
+	if (off >= count || user_count > count - off)
+		return -ENXIO;
+
+	return remap_pfn_range(vma, vma->vm_start,
+			page_to_pfn(page) + vma->vm_pgoff,
+			user_count << PAGE_SHIFT, vma->vm_page_prot);
+#else
+	return -ENXIO;
+#endif /* CONFIG_MMU */
+}
+
+struct page *dma_common_alloc_pages(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	struct page *page;
+
+	page = dma_alloc_contiguous(dev, size, gfp);
+	if (!page)
+		page = alloc_pages_node(dev_to_node(dev), gfp, get_order(size));
+	if (!page)
+		return NULL;
+
+	*dma_handle = ops->map_page(dev, page, 0, size, dir,
+				    DMA_ATTR_SKIP_CPU_SYNC);
+	if (*dma_handle == DMA_MAPPING_ERROR) {
+		dma_free_contiguous(dev, page, size);
+		return NULL;
+	}
+
+	memset(page_address(page), 0, size);
+	return page;
+}
+
+void dma_common_free_pages(struct device *dev, size_t size, struct page *page,
+		dma_addr_t dma_handle, enum dma_data_direction dir)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (ops->unmap_page)
+		ops->unmap_page(dev, dma_handle, size, dir,
+				DMA_ATTR_SKIP_CPU_SYNC);
+	dma_free_contiguous(dev, page, size);
+}
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
new file mode 100644
index 000000000..4d40dcce7
--- /dev/null
+++ b/kernel/dma/pool.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Copyright (C) 2020 Google LLC
+ */
+#include <linux/cma.h>
+#include <linux/debugfs.h>
+#include <linux/dma-map-ops.h>
+#include <linux/dma-direct.h>
+#include <linux/init.h>
+#include <linux/genalloc.h>
+#include <linux/set_memory.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+static struct gen_pool *atomic_pool_dma __ro_after_init;
+static unsigned long pool_size_dma;
+static struct gen_pool *atomic_pool_dma32 __ro_after_init;
+static unsigned long pool_size_dma32;
+static struct gen_pool *atomic_pool_kernel __ro_after_init;
+static unsigned long pool_size_kernel;
+
+/* Size can be defined by the coherent_pool command line */
+static size_t atomic_pool_size;
+
+/* Dynamic background expansion when the atomic pool is near capacity */
+static struct work_struct atomic_pool_work;
+
+static int __init early_coherent_pool(char *p)
+{
+	atomic_pool_size = memparse(p, &p);
+	return 0;
+}
+early_param("coherent_pool", early_coherent_pool);
+
+static void __init dma_atomic_pool_debugfs_init(void)
+{
+	struct dentry *root;
+
+	root = debugfs_create_dir("dma_pools", NULL);
+	debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma);
+	debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32);
+	debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel);
+}
+
+static void dma_atomic_pool_size_add(gfp_t gfp, size_t size)
+{
+	if (gfp & __GFP_DMA)
+		pool_size_dma += size;
+	else if (gfp & __GFP_DMA32)
+		pool_size_dma32 += size;
+	else
+		pool_size_kernel += size;
+}
+
+static bool cma_in_zone(gfp_t gfp)
+{
+	unsigned long size;
+	phys_addr_t end;
+	struct cma *cma;
+
+	cma = dev_get_cma_area(NULL);
+	if (!cma)
+		return false;
+
+	size = cma_get_size(cma);
+	if (!size)
+		return false;
+
+	/* CMA can't cross zone boundaries, see cma_activate_area() */
+	end = cma_get_base(cma) + size - 1;
+	if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA))
+		return end <= DMA_BIT_MASK(zone_dma_bits);
+	if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32))
+		return end <= DMA_BIT_MASK(32);
+	return true;
+}
+
+static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
+			      gfp_t gfp)
+{
+	unsigned int order;
+	struct page *page = NULL;
+	void *addr;
+	int ret = -ENOMEM;
+
+	/* Cannot allocate larger than MAX_ORDER-1 */
+	order = min(get_order(pool_size), MAX_ORDER-1);
+
+	do {
+		pool_size = 1 << (PAGE_SHIFT + order);
+		if (cma_in_zone(gfp))
+			page = dma_alloc_from_contiguous(NULL, 1 << order,
+							 order, false);
+		if (!page)
+			page = alloc_pages(gfp, order);
+	} while (!page && order-- > 0);
+	if (!page)
+		goto out;
+
+	arch_dma_prep_coherent(page, pool_size);
+
+#ifdef CONFIG_DMA_DIRECT_REMAP
+	addr = dma_common_contiguous_remap(page, pool_size,
+					   pgprot_dmacoherent(PAGE_KERNEL),
+					   __builtin_return_address(0));
+	if (!addr)
+		goto free_page;
+#else
+	addr = page_to_virt(page);
+#endif
+	/*
+	 * Memory in the atomic DMA pools must be unencrypted, the pools do not
+	 * shrink so no re-encryption occurs in dma_direct_free().
+	 */
+	ret = set_memory_decrypted((unsigned long)page_to_virt(page),
+				   1 << order);
+	if (ret)
+		goto remove_mapping;
+	ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page),
+				pool_size, NUMA_NO_NODE);
+	if (ret)
+		goto encrypt_mapping;
+
+	dma_atomic_pool_size_add(gfp, pool_size);
+	return 0;
+
+encrypt_mapping:
+	ret = set_memory_encrypted((unsigned long)page_to_virt(page),
+				   1 << order);
+	if (WARN_ON_ONCE(ret)) {
+		/* Decrypt succeeded but encrypt failed, purposely leak */
+		goto out;
+	}
+remove_mapping:
+#ifdef CONFIG_DMA_DIRECT_REMAP
+	dma_common_free_remap(addr, pool_size);
+#endif
+free_page: __maybe_unused
+	__free_pages(page, order);
+out:
+	return ret;
+}
+
+static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp)
+{
+	if (pool && gen_pool_avail(pool) < atomic_pool_size)
+		atomic_pool_expand(pool, gen_pool_size(pool), gfp);
+}
+
+static void atomic_pool_work_fn(struct work_struct *work)
+{
+	if (IS_ENABLED(CONFIG_ZONE_DMA))
+		atomic_pool_resize(atomic_pool_dma,
+				   GFP_KERNEL | GFP_DMA);
+	if (IS_ENABLED(CONFIG_ZONE_DMA32))
+		atomic_pool_resize(atomic_pool_dma32,
+				   GFP_KERNEL | GFP_DMA32);
+	atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL);
+}
+
+static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size,
+						      gfp_t gfp)
+{
+	struct gen_pool *pool;
+	int ret;
+
+	pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
+	if (!pool)
+		return NULL;
+
+	gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL);
+
+	ret = atomic_pool_expand(pool, pool_size, gfp);
+	if (ret) {
+		gen_pool_destroy(pool);
+		pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n",
+		       pool_size >> 10, &gfp);
+		return NULL;
+	}
+
+	pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n",
+		gen_pool_size(pool) >> 10, &gfp);
+	return pool;
+}
+
+static int __init dma_atomic_pool_init(void)
+{
+	int ret = 0;
+
+	/*
+	 * If coherent_pool was not used on the command line, default the pool
+	 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.
+	 */
+	if (!atomic_pool_size) {
+		unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);
+		pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
+		atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K);
+	}
+	INIT_WORK(&atomic_pool_work, atomic_pool_work_fn);
+
+	atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,
+						    GFP_KERNEL);
+	if (!atomic_pool_kernel)
+		ret = -ENOMEM;
+	if (has_managed_dma()) {
+		atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size,
+						GFP_KERNEL | GFP_DMA);
+		if (!atomic_pool_dma)
+			ret = -ENOMEM;
+	}
+	if (IS_ENABLED(CONFIG_ZONE_DMA32)) {
+		atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size,
+						GFP_KERNEL | GFP_DMA32);
+		if (!atomic_pool_dma32)
+			ret = -ENOMEM;
+	}
+
+	dma_atomic_pool_debugfs_init();
+	return ret;
+}
+postcore_initcall(dma_atomic_pool_init);
+
+static inline struct gen_pool *dma_guess_pool(struct gen_pool *prev, gfp_t gfp)
+{
+	if (prev == NULL) {
+		if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32))
+			return atomic_pool_dma32;
+		if (atomic_pool_dma && (gfp & GFP_DMA))
+			return atomic_pool_dma;
+		return atomic_pool_kernel;
+	}
+	if (prev == atomic_pool_kernel)
+		return atomic_pool_dma32 ? atomic_pool_dma32 : atomic_pool_dma;
+	if (prev == atomic_pool_dma32)
+		return atomic_pool_dma;
+	return NULL;
+}
+
+static struct page *__dma_alloc_from_pool(struct device *dev, size_t size,
+		struct gen_pool *pool, void **cpu_addr,
+		bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
+{
+	unsigned long addr;
+	phys_addr_t phys;
+
+	addr = gen_pool_alloc(pool, size);
+	if (!addr)
+		return NULL;
+
+	phys = gen_pool_virt_to_phys(pool, addr);
+	if (phys_addr_ok && !phys_addr_ok(dev, phys, size)) {
+		gen_pool_free(pool, addr, size);
+		return NULL;
+	}
+
+	if (gen_pool_avail(pool) < atomic_pool_size)
+		schedule_work(&atomic_pool_work);
+
+	*cpu_addr = (void *)addr;
+	memset(*cpu_addr, 0, size);
+	return pfn_to_page(__phys_to_pfn(phys));
+}
+
+struct page *dma_alloc_from_pool(struct device *dev, size_t size,
+		void **cpu_addr, gfp_t gfp,
+		bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
+{
+	struct gen_pool *pool = NULL;
+	struct page *page;
+
+	while ((pool = dma_guess_pool(pool, gfp))) {
+		page = __dma_alloc_from_pool(dev, size, pool, cpu_addr,
+					     phys_addr_ok);
+		if (page)
+			return page;
+	}
+
+	WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev));
+	return NULL;
+}
+
+bool dma_free_from_pool(struct device *dev, void *start, size_t size)
+{
+	struct gen_pool *pool = NULL;
+
+	while ((pool = dma_guess_pool(pool, 0))) {
+		if (!gen_pool_has_addr(pool, (unsigned long)start, size))
+			continue;
+		gen_pool_free(pool, (unsigned long)start, size);
+		return true;
+	}
+
+	return false;
+}
diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
new file mode 100644
index 000000000..27596f3b4
--- /dev/null
+++ b/kernel/dma/remap.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2014 The Linux Foundation
+ */
+#include <linux/dma-map-ops.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+struct page **dma_common_find_pages(void *cpu_addr)
+{
+	struct vm_struct *area = find_vm_area(cpu_addr);
+
+	if (!area || area->flags != VM_DMA_COHERENT)
+		return NULL;
+	return area->pages;
+}
+
+/*
+ * Remaps an array of PAGE_SIZE pages into another vm_area.
+ * Cannot be used in non-sleeping contexts
+ */
+void *dma_common_pages_remap(struct page **pages, size_t size,
+			 pgprot_t prot, const void *caller)
+{
+	void *vaddr;
+
+	vaddr = vmap(pages, PAGE_ALIGN(size) >> PAGE_SHIFT,
+		     VM_DMA_COHERENT, prot);
+	if (vaddr)
+		find_vm_area(vaddr)->pages = pages;
+	return vaddr;
+}
+
+/*
+ * Remaps an allocated contiguous region into another vm_area.
+ * Cannot be used in non-sleeping contexts
+ */
+void *dma_common_contiguous_remap(struct page *page, size_t size,
+			pgprot_t prot, const void *caller)
+{
+	int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	struct page **pages;
+	void *vaddr;
+	int i;
+
+	pages = kvmalloc_array(count, sizeof(struct page *), GFP_KERNEL);
+	if (!pages)
+		return NULL;
+	for (i = 0; i < count; i++)
+		pages[i] = nth_page(page, i);
+	vaddr = vmap(pages, count, VM_DMA_COHERENT, prot);
+	kvfree(pages);
+
+	return vaddr;
+}
+
+/*
+ * Unmaps a range previously mapped by dma_common_*_remap
+ */
+void dma_common_free_remap(void *cpu_addr, size_t size)
+{
+	struct vm_struct *area = find_vm_area(cpu_addr);
+
+	if (!area || area->flags != VM_DMA_COHERENT) {
+		WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
+		return;
+	}
+
+	vunmap(cpu_addr);
+}
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
new file mode 100644
index 000000000..ad6333c3f
--- /dev/null
+++ b/kernel/dma/swiotlb.c
@@ -0,0 +1,1105 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Dynamic DMA mapping support.
+ *
+ * This implementation is a fallback for platforms that do not support
+ * I/O TLBs (aka DMA address translation hardware).
+ * Copyright (C) 2000 Asit Mallick <Asit.K.Mallick@intel.com>
+ * Copyright (C) 2000 Goutham Rao <goutham.rao@intel.com>
+ * Copyright (C) 2000, 2003 Hewlett-Packard Co
+ *	David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ * 03/05/07 davidm	Switch from PCI-DMA to generic device DMA API.
+ * 00/12/13 davidm	Rename to swiotlb.c and add mark_clean() to avoid
+ *			unnecessary i-cache flushing.
+ * 04/07/.. ak		Better overflow handling. Assorted fixes.
+ * 05/09/10 linville	Add support for syncing ranges, support syncing for
+ *			DMA_BIDIRECTIONAL mappings, miscellaneous cleanup.
+ * 08/12/11 beckyb	Add highmem support
+ */
+
+#define pr_fmt(fmt) "software IO TLB: " fmt
+
+#include <linux/cache.h>
+#include <linux/cc_platform.h>
+#include <linux/ctype.h>
+#include <linux/debugfs.h>
+#include <linux/dma-direct.h>
+#include <linux/dma-map-ops.h>
+#include <linux/export.h>
+#include <linux/gfp.h>
+#include <linux/highmem.h>
+#include <linux/io.h>
+#include <linux/iommu-helper.h>
+#include <linux/init.h>
+#include <linux/memblock.h>
+#include <linux/mm.h>
+#include <linux/pfn.h>
+#include <linux/scatterlist.h>
+#include <linux/set_memory.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/swiotlb.h>
+#include <linux/types.h>
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/slab.h>
+#endif
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/swiotlb.h>
+
+#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
+
+/*
+ * Minimum IO TLB size to bother booting with.  Systems with mainly
+ * 64bit capable cards will only lightly use the swiotlb.  If we can't
+ * allocate a contiguous 1MB, we're probably in trouble anyway.
+ */
+#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
+
+#define INVALID_PHYS_ADDR (~(phys_addr_t)0)
+
+struct io_tlb_slot {
+	phys_addr_t orig_addr;
+	size_t alloc_size;
+	unsigned int list;
+};
+
+static bool swiotlb_force_bounce;
+static bool swiotlb_force_disable;
+
+struct io_tlb_mem io_tlb_default_mem;
+
+phys_addr_t swiotlb_unencrypted_base;
+
+static unsigned long default_nslabs = IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT;
+static unsigned long default_nareas;
+
+/**
+ * struct io_tlb_area - IO TLB memory area descriptor
+ *
+ * This is a single area with a single lock.
+ *
+ * @used:	The number of used IO TLB block.
+ * @index:	The slot index to start searching in this area for next round.
+ * @lock:	The lock to protect the above data structures in the map and
+ *		unmap calls.
+ */
+struct io_tlb_area {
+	unsigned long used;
+	unsigned int index;
+	spinlock_t lock;
+};
+
+/*
+ * Round up number of slabs to the next power of 2. The last area is going
+ * be smaller than the rest if default_nslabs is not power of two.
+ * The number of slot in an area should be a multiple of IO_TLB_SEGSIZE,
+ * otherwise a segment may span two or more areas. It conflicts with free
+ * contiguous slots tracking: free slots are treated contiguous no matter
+ * whether they cross an area boundary.
+ *
+ * Return true if default_nslabs is rounded up.
+ */
+static bool round_up_default_nslabs(void)
+{
+	if (!default_nareas)
+		return false;
+
+	if (default_nslabs < IO_TLB_SEGSIZE * default_nareas)
+		default_nslabs = IO_TLB_SEGSIZE * default_nareas;
+	else if (is_power_of_2(default_nslabs))
+		return false;
+	default_nslabs = roundup_pow_of_two(default_nslabs);
+	return true;
+}
+
+/**
+ * swiotlb_adjust_nareas() - adjust the number of areas and slots
+ * @nareas:	Desired number of areas. Zero is treated as 1.
+ *
+ * Adjust the default number of areas in a memory pool.
+ * The default size of the memory pool may also change to meet minimum area
+ * size requirements.
+ */
+static void swiotlb_adjust_nareas(unsigned int nareas)
+{
+	if (!nareas)
+		nareas = 1;
+	else if (!is_power_of_2(nareas))
+		nareas = roundup_pow_of_two(nareas);
+
+	default_nareas = nareas;
+
+	pr_info("area num %d.\n", nareas);
+	if (round_up_default_nslabs())
+		pr_info("SWIOTLB bounce buffer size roundup to %luMB",
+			(default_nslabs << IO_TLB_SHIFT) >> 20);
+}
+
+/**
+ * limit_nareas() - get the maximum number of areas for a given memory pool size
+ * @nareas:	Desired number of areas.
+ * @nslots:	Total number of slots in the memory pool.
+ *
+ * Limit the number of areas to the maximum possible number of areas in
+ * a memory pool of the given size.
+ *
+ * Return: Maximum possible number of areas.
+ */
+static unsigned int limit_nareas(unsigned int nareas, unsigned long nslots)
+{
+	if (nslots < nareas * IO_TLB_SEGSIZE)
+		return nslots / IO_TLB_SEGSIZE;
+	return nareas;
+}
+
+static int __init
+setup_io_tlb_npages(char *str)
+{
+	if (isdigit(*str)) {
+		/* avoid tail segment of size < IO_TLB_SEGSIZE */
+		default_nslabs =
+			ALIGN(simple_strtoul(str, &str, 0), IO_TLB_SEGSIZE);
+	}
+	if (*str == ',')
+		++str;
+	if (isdigit(*str))
+		swiotlb_adjust_nareas(simple_strtoul(str, &str, 0));
+	if (*str == ',')
+		++str;
+	if (!strcmp(str, "force"))
+		swiotlb_force_bounce = true;
+	else if (!strcmp(str, "noforce"))
+		swiotlb_force_disable = true;
+
+	return 0;
+}
+early_param("swiotlb", setup_io_tlb_npages);
+
+unsigned int swiotlb_max_segment(void)
+{
+	if (!io_tlb_default_mem.nslabs)
+		return 0;
+	return rounddown(io_tlb_default_mem.nslabs << IO_TLB_SHIFT, PAGE_SIZE);
+}
+EXPORT_SYMBOL_GPL(swiotlb_max_segment);
+
+unsigned long swiotlb_size_or_default(void)
+{
+	return default_nslabs << IO_TLB_SHIFT;
+}
+
+void __init swiotlb_adjust_size(unsigned long size)
+{
+	/*
+	 * If swiotlb parameter has not been specified, give a chance to
+	 * architectures such as those supporting memory encryption to
+	 * adjust/expand SWIOTLB size for their use.
+	 */
+	if (default_nslabs != IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT)
+		return;
+
+	size = ALIGN(size, IO_TLB_SIZE);
+	default_nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
+	if (round_up_default_nslabs())
+		size = default_nslabs << IO_TLB_SHIFT;
+	pr_info("SWIOTLB bounce buffer size adjusted to %luMB", size >> 20);
+}
+
+void swiotlb_print_info(void)
+{
+	struct io_tlb_mem *mem = &io_tlb_default_mem;
+
+	if (!mem->nslabs) {
+		pr_warn("No low mem\n");
+		return;
+	}
+
+	pr_info("mapped [mem %pa-%pa] (%luMB)\n", &mem->start, &mem->end,
+	       (mem->nslabs << IO_TLB_SHIFT) >> 20);
+}
+
+static inline unsigned long io_tlb_offset(unsigned long val)
+{
+	return val & (IO_TLB_SEGSIZE - 1);
+}
+
+static inline unsigned long nr_slots(u64 val)
+{
+	return DIV_ROUND_UP(val, IO_TLB_SIZE);
+}
+
+/*
+ * Remap swioltb memory in the unencrypted physical address space
+ * when swiotlb_unencrypted_base is set. (e.g. for Hyper-V AMD SEV-SNP
+ * Isolation VMs).
+ */
+#ifdef CONFIG_HAS_IOMEM
+static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
+{
+	void *vaddr = NULL;
+
+	if (swiotlb_unencrypted_base) {
+		phys_addr_t paddr = mem->start + swiotlb_unencrypted_base;
+
+		vaddr = memremap(paddr, bytes, MEMREMAP_WB);
+		if (!vaddr)
+			pr_err("Failed to map the unencrypted memory %pa size %lx.\n",
+			       &paddr, bytes);
+	}
+
+	return vaddr;
+}
+#else
+static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
+{
+	return NULL;
+}
+#endif
+
+/*
+ * Early SWIOTLB allocation may be too early to allow an architecture to
+ * perform the desired operations.  This function allows the architecture to
+ * call SWIOTLB when the operations are possible.  It needs to be called
+ * before the SWIOTLB memory is used.
+ */
+void __init swiotlb_update_mem_attributes(void)
+{
+	struct io_tlb_mem *mem = &io_tlb_default_mem;
+	void *vaddr;
+	unsigned long bytes;
+
+	if (!mem->nslabs || mem->late_alloc)
+		return;
+	vaddr = phys_to_virt(mem->start);
+	bytes = PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT);
+	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
+
+	mem->vaddr = swiotlb_mem_remap(mem, bytes);
+	if (!mem->vaddr)
+		mem->vaddr = vaddr;
+}
+
+static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
+		unsigned long nslabs, unsigned int flags,
+		bool late_alloc, unsigned int nareas)
+{
+	void *vaddr = phys_to_virt(start);
+	unsigned long bytes = nslabs << IO_TLB_SHIFT, i;
+
+	mem->nslabs = nslabs;
+	mem->start = start;
+	mem->end = mem->start + bytes;
+	mem->late_alloc = late_alloc;
+	mem->nareas = nareas;
+	mem->area_nslabs = nslabs / mem->nareas;
+
+	mem->force_bounce = swiotlb_force_bounce || (flags & SWIOTLB_FORCE);
+
+	for (i = 0; i < mem->nareas; i++) {
+		spin_lock_init(&mem->areas[i].lock);
+		mem->areas[i].index = 0;
+		mem->areas[i].used = 0;
+	}
+
+	for (i = 0; i < mem->nslabs; i++) {
+		mem->slots[i].list = IO_TLB_SEGSIZE - io_tlb_offset(i);
+		mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
+		mem->slots[i].alloc_size = 0;
+	}
+
+	/*
+	 * If swiotlb_unencrypted_base is set, the bounce buffer memory will
+	 * be remapped and cleared in swiotlb_update_mem_attributes.
+	 */
+	if (swiotlb_unencrypted_base)
+		return;
+
+	memset(vaddr, 0, bytes);
+	mem->vaddr = vaddr;
+	return;
+}
+
+static void __init *swiotlb_memblock_alloc(unsigned long nslabs,
+		unsigned int flags,
+		int (*remap)(void *tlb, unsigned long nslabs))
+{
+	size_t bytes = PAGE_ALIGN(nslabs << IO_TLB_SHIFT);
+	void *tlb;
+
+	/*
+	 * By default allocate the bounce buffer memory from low memory, but
+	 * allow to pick a location everywhere for hypervisors with guest
+	 * memory encryption.
+	 */
+	if (flags & SWIOTLB_ANY)
+		tlb = memblock_alloc(bytes, PAGE_SIZE);
+	else
+		tlb = memblock_alloc_low(bytes, PAGE_SIZE);
+
+	if (!tlb) {
+		pr_warn("%s: Failed to allocate %zu bytes tlb structure\n",
+			__func__, bytes);
+		return NULL;
+	}
+
+	if (remap && remap(tlb, nslabs) < 0) {
+		memblock_free(tlb, PAGE_ALIGN(bytes));
+		pr_warn("%s: Failed to remap %zu bytes\n", __func__, bytes);
+		return NULL;
+	}
+
+	return tlb;
+}
+
+/*
+ * Statically reserve bounce buffer space and initialize bounce buffer data
+ * structures for the software IO TLB used to implement the DMA API.
+ */
+void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
+		int (*remap)(void *tlb, unsigned long nslabs))
+{
+	struct io_tlb_mem *mem = &io_tlb_default_mem;
+	unsigned long nslabs;
+	unsigned int nareas;
+	size_t alloc_size;
+	void *tlb;
+
+	if (!addressing_limit && !swiotlb_force_bounce)
+		return;
+	if (swiotlb_force_disable)
+		return;
+
+	if (!default_nareas)
+		swiotlb_adjust_nareas(num_possible_cpus());
+
+	nslabs = default_nslabs;
+	nareas = limit_nareas(default_nareas, nslabs);
+	while ((tlb = swiotlb_memblock_alloc(nslabs, flags, remap)) == NULL) {
+		if (nslabs <= IO_TLB_MIN_SLABS)
+			return;
+		nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE);
+		nareas = limit_nareas(nareas, nslabs);
+	}
+
+	if (default_nslabs != nslabs) {
+		pr_info("SWIOTLB bounce buffer size adjusted %lu -> %lu slabs",
+			default_nslabs, nslabs);
+		default_nslabs = nslabs;
+	}
+
+	alloc_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), nslabs));
+	mem->slots = memblock_alloc(alloc_size, PAGE_SIZE);
+	if (!mem->slots) {
+		pr_warn("%s: Failed to allocate %zu bytes align=0x%lx\n",
+			__func__, alloc_size, PAGE_SIZE);
+		return;
+	}
+
+	mem->areas = memblock_alloc(array_size(sizeof(struct io_tlb_area),
+		default_nareas), SMP_CACHE_BYTES);
+	if (!mem->areas) {
+		pr_warn("%s: Failed to allocate mem->areas.\n", __func__);
+		return;
+	}
+
+	swiotlb_init_io_tlb_mem(mem, __pa(tlb), nslabs, flags, false,
+				default_nareas);
+
+	if (flags & SWIOTLB_VERBOSE)
+		swiotlb_print_info();
+}
+
+void __init swiotlb_init(bool addressing_limit, unsigned int flags)
+{
+	swiotlb_init_remap(addressing_limit, flags, NULL);
+}
+
+/*
+ * Systems with larger DMA zones (those that don't support ISA) can
+ * initialize the swiotlb later using the slab allocator if needed.
+ * This should be just like above, but with some error catching.
+ */
+int swiotlb_init_late(size_t size, gfp_t gfp_mask,
+		int (*remap)(void *tlb, unsigned long nslabs))
+{
+	struct io_tlb_mem *mem = &io_tlb_default_mem;
+	unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
+	unsigned int nareas;
+	unsigned char *vstart = NULL;
+	unsigned int order, area_order;
+	bool retried = false;
+	int rc = 0;
+
+	if (swiotlb_force_disable)
+		return 0;
+
+	if (!default_nareas)
+		swiotlb_adjust_nareas(num_possible_cpus());
+
+retry:
+	order = get_order(nslabs << IO_TLB_SHIFT);
+	nslabs = SLABS_PER_PAGE << order;
+
+	while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
+		vstart = (void *)__get_free_pages(gfp_mask | __GFP_NOWARN,
+						  order);
+		if (vstart)
+			break;
+		order--;
+		nslabs = SLABS_PER_PAGE << order;
+		retried = true;
+	}
+
+	if (!vstart)
+		return -ENOMEM;
+
+	if (remap)
+		rc = remap(vstart, nslabs);
+	if (rc) {
+		free_pages((unsigned long)vstart, order);
+
+		nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE);
+		if (nslabs < IO_TLB_MIN_SLABS)
+			return rc;
+		retried = true;
+		goto retry;
+	}
+
+	if (retried) {
+		pr_warn("only able to allocate %ld MB\n",
+			(PAGE_SIZE << order) >> 20);
+	}
+
+	nareas = limit_nareas(default_nareas, nslabs);
+	area_order = get_order(array_size(sizeof(*mem->areas), nareas));
+	mem->areas = (struct io_tlb_area *)
+		__get_free_pages(GFP_KERNEL | __GFP_ZERO, area_order);
+	if (!mem->areas)
+		goto error_area;
+
+	mem->slots = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+		get_order(array_size(sizeof(*mem->slots), nslabs)));
+	if (!mem->slots)
+		goto error_slots;
+
+	set_memory_decrypted((unsigned long)vstart,
+			     (nslabs << IO_TLB_SHIFT) >> PAGE_SHIFT);
+	swiotlb_init_io_tlb_mem(mem, virt_to_phys(vstart), nslabs, 0, true,
+				nareas);
+
+	swiotlb_print_info();
+	return 0;
+
+error_slots:
+	free_pages((unsigned long)mem->areas, area_order);
+error_area:
+	free_pages((unsigned long)vstart, order);
+	return -ENOMEM;
+}
+
+void __init swiotlb_exit(void)
+{
+	struct io_tlb_mem *mem = &io_tlb_default_mem;
+	unsigned long tbl_vaddr;
+	size_t tbl_size, slots_size;
+	unsigned int area_order;
+
+	if (swiotlb_force_bounce)
+		return;
+
+	if (!mem->nslabs)
+		return;
+
+	pr_info("tearing down default memory pool\n");
+	tbl_vaddr = (unsigned long)phys_to_virt(mem->start);
+	tbl_size = PAGE_ALIGN(mem->end - mem->start);
+	slots_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), mem->nslabs));
+
+	set_memory_encrypted(tbl_vaddr, tbl_size >> PAGE_SHIFT);
+	if (mem->late_alloc) {
+		area_order = get_order(array_size(sizeof(*mem->areas),
+			mem->nareas));
+		free_pages((unsigned long)mem->areas, area_order);
+		free_pages(tbl_vaddr, get_order(tbl_size));
+		free_pages((unsigned long)mem->slots, get_order(slots_size));
+	} else {
+		memblock_free_late(__pa(mem->areas),
+			array_size(sizeof(*mem->areas), mem->nareas));
+		memblock_free_late(mem->start, tbl_size);
+		memblock_free_late(__pa(mem->slots), slots_size);
+	}
+
+	memset(mem, 0, sizeof(*mem));
+}
+
+/*
+ * Return the offset into a iotlb slot required to keep the device happy.
+ */
+static unsigned int swiotlb_align_offset(struct device *dev, u64 addr)
+{
+	return addr & dma_get_min_align_mask(dev) & (IO_TLB_SIZE - 1);
+}
+
+/*
+ * Bounce: copy the swiotlb buffer from or back to the original dma location
+ */
+static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size,
+			   enum dma_data_direction dir)
+{
+	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
+	int index = (tlb_addr - mem->start) >> IO_TLB_SHIFT;
+	phys_addr_t orig_addr = mem->slots[index].orig_addr;
+	size_t alloc_size = mem->slots[index].alloc_size;
+	unsigned long pfn = PFN_DOWN(orig_addr);
+	unsigned char *vaddr = mem->vaddr + tlb_addr - mem->start;
+	unsigned int tlb_offset, orig_addr_offset;
+
+	if (orig_addr == INVALID_PHYS_ADDR)
+		return;
+
+	tlb_offset = tlb_addr & (IO_TLB_SIZE - 1);
+	orig_addr_offset = swiotlb_align_offset(dev, orig_addr);
+	if (tlb_offset < orig_addr_offset) {
+		dev_WARN_ONCE(dev, 1,
+			"Access before mapping start detected. orig offset %u, requested offset %u.\n",
+			orig_addr_offset, tlb_offset);
+		return;
+	}
+
+	tlb_offset -= orig_addr_offset;
+	if (tlb_offset > alloc_size) {
+		dev_WARN_ONCE(dev, 1,
+			"Buffer overflow detected. Allocation size: %zu. Mapping size: %zu+%u.\n",
+			alloc_size, size, tlb_offset);
+		return;
+	}
+
+	orig_addr += tlb_offset;
+	alloc_size -= tlb_offset;
+
+	if (size > alloc_size) {
+		dev_WARN_ONCE(dev, 1,
+			"Buffer overflow detected. Allocation size: %zu. Mapping size: %zu.\n",
+			alloc_size, size);
+		size = alloc_size;
+	}
+
+	if (PageHighMem(pfn_to_page(pfn))) {
+		unsigned int offset = orig_addr & ~PAGE_MASK;
+		struct page *page;
+		unsigned int sz = 0;
+		unsigned long flags;
+
+		while (size) {
+			sz = min_t(size_t, PAGE_SIZE - offset, size);
+
+			local_irq_save(flags);
+			page = pfn_to_page(pfn);
+			if (dir == DMA_TO_DEVICE)
+				memcpy_from_page(vaddr, page, offset, sz);
+			else
+				memcpy_to_page(page, offset, vaddr, sz);
+			local_irq_restore(flags);
+
+			size -= sz;
+			pfn++;
+			vaddr += sz;
+			offset = 0;
+		}
+	} else if (dir == DMA_TO_DEVICE) {
+		memcpy(vaddr, phys_to_virt(orig_addr), size);
+	} else {
+		memcpy(phys_to_virt(orig_addr), vaddr, size);
+	}
+}
+
+static inline phys_addr_t slot_addr(phys_addr_t start, phys_addr_t idx)
+{
+	return start + (idx << IO_TLB_SHIFT);
+}
+
+/*
+ * Carefully handle integer overflow which can occur when boundary_mask == ~0UL.
+ */
+static inline unsigned long get_max_slots(unsigned long boundary_mask)
+{
+	if (boundary_mask == ~0UL)
+		return 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
+	return nr_slots(boundary_mask + 1);
+}
+
+static unsigned int wrap_area_index(struct io_tlb_mem *mem, unsigned int index)
+{
+	if (index >= mem->area_nslabs)
+		return 0;
+	return index;
+}
+
+/*
+ * Find a suitable number of IO TLB entries size that will fit this request and
+ * allocate a buffer from that IO TLB pool.
+ */
+static int swiotlb_do_find_slots(struct device *dev, int area_index,
+		phys_addr_t orig_addr, size_t alloc_size,
+		unsigned int alloc_align_mask)
+{
+	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
+	struct io_tlb_area *area = mem->areas + area_index;
+	unsigned long boundary_mask = dma_get_seg_boundary(dev);
+	dma_addr_t tbl_dma_addr =
+		phys_to_dma_unencrypted(dev, mem->start) & boundary_mask;
+	unsigned long max_slots = get_max_slots(boundary_mask);
+	unsigned int iotlb_align_mask =
+		dma_get_min_align_mask(dev) & ~(IO_TLB_SIZE - 1);
+	unsigned int nslots = nr_slots(alloc_size), stride;
+	unsigned int index, wrap, count = 0, i;
+	unsigned int offset = swiotlb_align_offset(dev, orig_addr);
+	unsigned long flags;
+	unsigned int slot_base;
+	unsigned int slot_index;
+
+	BUG_ON(!nslots);
+	BUG_ON(area_index >= mem->nareas);
+
+	/*
+	 * For mappings with an alignment requirement don't bother looping to
+	 * unaligned slots once we found an aligned one.  For allocations of
+	 * PAGE_SIZE or larger only look for page aligned allocations.
+	 */
+	stride = (iotlb_align_mask >> IO_TLB_SHIFT) + 1;
+	if (alloc_size >= PAGE_SIZE)
+		stride = max(stride, stride << (PAGE_SHIFT - IO_TLB_SHIFT));
+	stride = max(stride, (alloc_align_mask >> IO_TLB_SHIFT) + 1);
+
+	spin_lock_irqsave(&area->lock, flags);
+	if (unlikely(nslots > mem->area_nslabs - area->used))
+		goto not_found;
+
+	slot_base = area_index * mem->area_nslabs;
+	index = wrap = wrap_area_index(mem, ALIGN(area->index, stride));
+
+	do {
+		slot_index = slot_base + index;
+
+		if (orig_addr &&
+		    (slot_addr(tbl_dma_addr, slot_index) &
+		     iotlb_align_mask) != (orig_addr & iotlb_align_mask)) {
+			index = wrap_area_index(mem, index + 1);
+			continue;
+		}
+
+		/*
+		 * If we find a slot that indicates we have 'nslots' number of
+		 * contiguous buffers, we allocate the buffers from that slot
+		 * and mark the entries as '0' indicating unavailable.
+		 */
+		if (!iommu_is_span_boundary(slot_index, nslots,
+					    nr_slots(tbl_dma_addr),
+					    max_slots)) {
+			if (mem->slots[slot_index].list >= nslots)
+				goto found;
+		}
+		index = wrap_area_index(mem, index + stride);
+	} while (index != wrap);
+
+not_found:
+	spin_unlock_irqrestore(&area->lock, flags);
+	return -1;
+
+found:
+	for (i = slot_index; i < slot_index + nslots; i++) {
+		mem->slots[i].list = 0;
+		mem->slots[i].alloc_size = alloc_size - (offset +
+				((i - slot_index) << IO_TLB_SHIFT));
+	}
+	for (i = slot_index - 1;
+	     io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 &&
+	     mem->slots[i].list; i--)
+		mem->slots[i].list = ++count;
+
+	/*
+	 * Update the indices to avoid searching in the next round.
+	 */
+	if (index + nslots < mem->area_nslabs)
+		area->index = index + nslots;
+	else
+		area->index = 0;
+	area->used += nslots;
+	spin_unlock_irqrestore(&area->lock, flags);
+	return slot_index;
+}
+
+static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr,
+		size_t alloc_size, unsigned int alloc_align_mask)
+{
+	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
+	int start = raw_smp_processor_id() & (mem->nareas - 1);
+	int i = start, index;
+
+	do {
+		index = swiotlb_do_find_slots(dev, i, orig_addr, alloc_size,
+					      alloc_align_mask);
+		if (index >= 0)
+			return index;
+		if (++i >= mem->nareas)
+			i = 0;
+	} while (i != start);
+
+	return -1;
+}
+
+static unsigned long mem_used(struct io_tlb_mem *mem)
+{
+	int i;
+	unsigned long used = 0;
+
+	for (i = 0; i < mem->nareas; i++)
+		used += mem->areas[i].used;
+	return used;
+}
+
+phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
+		size_t mapping_size, size_t alloc_size,
+		unsigned int alloc_align_mask, enum dma_data_direction dir,
+		unsigned long attrs)
+{
+	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
+	unsigned int offset = swiotlb_align_offset(dev, orig_addr);
+	unsigned int i;
+	int index;
+	phys_addr_t tlb_addr;
+
+	if (!mem || !mem->nslabs) {
+		dev_warn_ratelimited(dev,
+			"Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
+		return (phys_addr_t)DMA_MAPPING_ERROR;
+	}
+
+	if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
+		pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
+
+	if (mapping_size > alloc_size) {
+		dev_warn_once(dev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)",
+			      mapping_size, alloc_size);
+		return (phys_addr_t)DMA_MAPPING_ERROR;
+	}
+
+	index = swiotlb_find_slots(dev, orig_addr,
+				   alloc_size + offset, alloc_align_mask);
+	if (index == -1) {
+		if (!(attrs & DMA_ATTR_NO_WARN))
+			dev_warn_ratelimited(dev,
+	"swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
+				 alloc_size, mem->nslabs, mem_used(mem));
+		return (phys_addr_t)DMA_MAPPING_ERROR;
+	}
+
+	/*
+	 * Save away the mapping from the original address to the DMA address.
+	 * This is needed when we sync the memory.  Then we sync the buffer if
+	 * needed.
+	 */
+	for (i = 0; i < nr_slots(alloc_size + offset); i++)
+		mem->slots[index + i].orig_addr = slot_addr(orig_addr, i);
+	tlb_addr = slot_addr(mem->start, index) + offset;
+	/*
+	 * When dir == DMA_FROM_DEVICE we could omit the copy from the orig
+	 * to the tlb buffer, if we knew for sure the device will
+	 * overwrite the entire current content. But we don't. Thus
+	 * unconditional bounce may prevent leaking swiotlb content (i.e.
+	 * kernel memory) to user-space.
+	 */
+	swiotlb_bounce(dev, tlb_addr, mapping_size, DMA_TO_DEVICE);
+	return tlb_addr;
+}
+
+static void swiotlb_release_slots(struct device *dev, phys_addr_t tlb_addr)
+{
+	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
+	unsigned long flags;
+	unsigned int offset = swiotlb_align_offset(dev, tlb_addr);
+	int index = (tlb_addr - offset - mem->start) >> IO_TLB_SHIFT;
+	int nslots = nr_slots(mem->slots[index].alloc_size + offset);
+	int aindex = index / mem->area_nslabs;
+	struct io_tlb_area *area = &mem->areas[aindex];
+	int count, i;
+
+	/*
+	 * Return the buffer to the free list by setting the corresponding
+	 * entries to indicate the number of contiguous entries available.
+	 * While returning the entries to the free list, we merge the entries
+	 * with slots below and above the pool being returned.
+	 */
+	BUG_ON(aindex >= mem->nareas);
+
+	spin_lock_irqsave(&area->lock, flags);
+	if (index + nslots < ALIGN(index + 1, IO_TLB_SEGSIZE))
+		count = mem->slots[index + nslots].list;
+	else
+		count = 0;
+
+	/*
+	 * Step 1: return the slots to the free list, merging the slots with
+	 * superceeding slots
+	 */
+	for (i = index + nslots - 1; i >= index; i--) {
+		mem->slots[i].list = ++count;
+		mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
+		mem->slots[i].alloc_size = 0;
+	}
+
+	/*
+	 * Step 2: merge the returned slots with the preceding slots, if
+	 * available (non zero)
+	 */
+	for (i = index - 1;
+	     io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 && mem->slots[i].list;
+	     i--)
+		mem->slots[i].list = ++count;
+	area->used -= nslots;
+	spin_unlock_irqrestore(&area->lock, flags);
+}
+
+/*
+ * tlb_addr is the physical address of the bounce buffer to unmap.
+ */
+void swiotlb_tbl_unmap_single(struct device *dev, phys_addr_t tlb_addr,
+			      size_t mapping_size, enum dma_data_direction dir,
+			      unsigned long attrs)
+{
+	/*
+	 * First, sync the memory before unmapping the entry
+	 */
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+	    (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
+		swiotlb_bounce(dev, tlb_addr, mapping_size, DMA_FROM_DEVICE);
+
+	swiotlb_release_slots(dev, tlb_addr);
+}
+
+void swiotlb_sync_single_for_device(struct device *dev, phys_addr_t tlb_addr,
+		size_t size, enum dma_data_direction dir)
+{
+	if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
+		swiotlb_bounce(dev, tlb_addr, size, DMA_TO_DEVICE);
+	else
+		BUG_ON(dir != DMA_FROM_DEVICE);
+}
+
+void swiotlb_sync_single_for_cpu(struct device *dev, phys_addr_t tlb_addr,
+		size_t size, enum dma_data_direction dir)
+{
+	if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)
+		swiotlb_bounce(dev, tlb_addr, size, DMA_FROM_DEVICE);
+	else
+		BUG_ON(dir != DMA_TO_DEVICE);
+}
+
+/*
+ * Create a swiotlb mapping for the buffer at @paddr, and in case of DMAing
+ * to the device copy the data into it as well.
+ */
+dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size,
+		enum dma_data_direction dir, unsigned long attrs)
+{
+	phys_addr_t swiotlb_addr;
+	dma_addr_t dma_addr;
+
+	trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size);
+
+	swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, size, 0, dir,
+			attrs);
+	if (swiotlb_addr == (phys_addr_t)DMA_MAPPING_ERROR)
+		return DMA_MAPPING_ERROR;
+
+	/* Ensure that the address returned is DMA'ble */
+	dma_addr = phys_to_dma_unencrypted(dev, swiotlb_addr);
+	if (unlikely(!dma_capable(dev, dma_addr, size, true))) {
+		swiotlb_tbl_unmap_single(dev, swiotlb_addr, size, dir,
+			attrs | DMA_ATTR_SKIP_CPU_SYNC);
+		dev_WARN_ONCE(dev, 1,
+			"swiotlb addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
+			&dma_addr, size, *dev->dma_mask, dev->bus_dma_limit);
+		return DMA_MAPPING_ERROR;
+	}
+
+	if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		arch_sync_dma_for_device(swiotlb_addr, size, dir);
+	return dma_addr;
+}
+
+size_t swiotlb_max_mapping_size(struct device *dev)
+{
+	int min_align_mask = dma_get_min_align_mask(dev);
+	int min_align = 0;
+
+	/*
+	 * swiotlb_find_slots() skips slots according to
+	 * min align mask. This affects max mapping size.
+	 * Take it into acount here.
+	 */
+	if (min_align_mask)
+		min_align = roundup(min_align_mask, IO_TLB_SIZE);
+
+	return ((size_t)IO_TLB_SIZE) * IO_TLB_SEGSIZE - min_align;
+}
+
+bool is_swiotlb_active(struct device *dev)
+{
+	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
+
+	return mem && mem->nslabs;
+}
+EXPORT_SYMBOL_GPL(is_swiotlb_active);
+
+static int io_tlb_used_get(void *data, u64 *val)
+{
+	struct io_tlb_mem *mem = data;
+
+	*val = mem_used(mem);
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(fops_io_tlb_used, io_tlb_used_get, NULL, "%llu\n");
+
+static void swiotlb_create_debugfs_files(struct io_tlb_mem *mem,
+					 const char *dirname)
+{
+	mem->debugfs = debugfs_create_dir(dirname, io_tlb_default_mem.debugfs);
+	if (!mem->nslabs)
+		return;
+
+	debugfs_create_ulong("io_tlb_nslabs", 0400, mem->debugfs, &mem->nslabs);
+	debugfs_create_file("io_tlb_used", 0400, mem->debugfs, mem,
+			&fops_io_tlb_used);
+}
+
+static int __init __maybe_unused swiotlb_create_default_debugfs(void)
+{
+	swiotlb_create_debugfs_files(&io_tlb_default_mem, "swiotlb");
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+late_initcall(swiotlb_create_default_debugfs);
+#endif
+
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+
+struct page *swiotlb_alloc(struct device *dev, size_t size)
+{
+	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
+	phys_addr_t tlb_addr;
+	int index;
+
+	if (!mem)
+		return NULL;
+
+	index = swiotlb_find_slots(dev, 0, size, 0);
+	if (index == -1)
+		return NULL;
+
+	tlb_addr = slot_addr(mem->start, index);
+
+	return pfn_to_page(PFN_DOWN(tlb_addr));
+}
+
+bool swiotlb_free(struct device *dev, struct page *page, size_t size)
+{
+	phys_addr_t tlb_addr = page_to_phys(page);
+
+	if (!is_swiotlb_buffer(dev, tlb_addr))
+		return false;
+
+	swiotlb_release_slots(dev, tlb_addr);
+
+	return true;
+}
+
+static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
+				    struct device *dev)
+{
+	struct io_tlb_mem *mem = rmem->priv;
+	unsigned long nslabs = rmem->size >> IO_TLB_SHIFT;
+
+	/* Set Per-device io tlb area to one */
+	unsigned int nareas = 1;
+
+	if (PageHighMem(pfn_to_page(PHYS_PFN(rmem->base)))) {
+		dev_err(dev, "Restricted DMA pool must be accessible within the linear mapping.");
+		return -EINVAL;
+	}
+
+	/*
+	 * Since multiple devices can share the same pool, the private data,
+	 * io_tlb_mem struct, will be initialized by the first device attached
+	 * to it.
+	 */
+	if (!mem) {
+		mem = kzalloc(sizeof(*mem), GFP_KERNEL);
+		if (!mem)
+			return -ENOMEM;
+
+		mem->slots = kcalloc(nslabs, sizeof(*mem->slots), GFP_KERNEL);
+		if (!mem->slots) {
+			kfree(mem);
+			return -ENOMEM;
+		}
+
+		mem->areas = kcalloc(nareas, sizeof(*mem->areas),
+				GFP_KERNEL);
+		if (!mem->areas) {
+			kfree(mem->slots);
+			kfree(mem);
+			return -ENOMEM;
+		}
+
+		set_memory_decrypted((unsigned long)phys_to_virt(rmem->base),
+				     rmem->size >> PAGE_SHIFT);
+		swiotlb_init_io_tlb_mem(mem, rmem->base, nslabs, SWIOTLB_FORCE,
+					false, nareas);
+		mem->for_alloc = true;
+
+		rmem->priv = mem;
+
+		swiotlb_create_debugfs_files(mem, rmem->name);
+	}
+
+	dev->dma_io_tlb_mem = mem;
+
+	return 0;
+}
+
+static void rmem_swiotlb_device_release(struct reserved_mem *rmem,
+					struct device *dev)
+{
+	dev->dma_io_tlb_mem = &io_tlb_default_mem;
+}
+
+static const struct reserved_mem_ops rmem_swiotlb_ops = {
+	.device_init = rmem_swiotlb_device_init,
+	.device_release = rmem_swiotlb_device_release,
+};
+
+static int __init rmem_swiotlb_setup(struct reserved_mem *rmem)
+{
+	unsigned long node = rmem->fdt_node;
+
+	if (of_get_flat_dt_prop(node, "reusable", NULL) ||
+	    of_get_flat_dt_prop(node, "linux,cma-default", NULL) ||
+	    of_get_flat_dt_prop(node, "linux,dma-default", NULL) ||
+	    of_get_flat_dt_prop(node, "no-map", NULL))
+		return -EINVAL;
+
+	rmem->ops = &rmem_swiotlb_ops;
+	pr_info("Reserved memory: created restricted DMA pool at %pa, size %ld MiB\n",
+		&rmem->base, (unsigned long)rmem->size / SZ_1M);
+	return 0;
+}
+
+RESERVEDMEM_OF_DECLARE(dma, "restricted-dma-pool", rmem_swiotlb_setup);
+#endif /* CONFIG_DMA_RESTRICTED_POOL */
diff --git a/kernel/entry/Makefile b/kernel/entry/Makefile
new file mode 100644
index 000000000..095c775e0
--- /dev/null
+++ b/kernel/entry/Makefile
@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# Prevent the noinstr section from being pestered by sanitizer and other goodies
+# as long as these things cannot be disabled per function.
+KASAN_SANITIZE := n
+UBSAN_SANITIZE := n
+KCOV_INSTRUMENT := n
+
+CFLAGS_REMOVE_common.o	 = -fstack-protector -fstack-protector-strong
+CFLAGS_common.o		+= -fno-stack-protector
+
+obj-$(CONFIG_GENERIC_ENTRY) 		+= common.o syscall_user_dispatch.o
+obj-$(CONFIG_KVM_XFER_TO_GUEST_WORK)	+= kvm.o
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
new file mode 100644
index 000000000..be61332c6
--- /dev/null
+++ b/kernel/entry/common.c
@@ -0,0 +1,483 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/context_tracking.h>
+#include <linux/entry-common.h>
+#include <linux/resume_user_mode.h>
+#include <linux/highmem.h>
+#include <linux/jump_label.h>
+#include <linux/kmsan.h>
+#include <linux/livepatch.h>
+#include <linux/audit.h>
+#include <linux/tick.h>
+
+#include "common.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/syscalls.h>
+
+/* See comment for enter_from_user_mode() in entry-common.h */
+static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
+{
+	arch_enter_from_user_mode(regs);
+	lockdep_hardirqs_off(CALLER_ADDR0);
+
+	CT_WARN_ON(__ct_state() != CONTEXT_USER);
+	user_exit_irqoff();
+
+	instrumentation_begin();
+	kmsan_unpoison_entry_regs(regs);
+	trace_hardirqs_off_finish();
+	instrumentation_end();
+}
+
+void noinstr enter_from_user_mode(struct pt_regs *regs)
+{
+	__enter_from_user_mode(regs);
+}
+
+static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
+{
+	if (unlikely(audit_context())) {
+		unsigned long args[6];
+
+		syscall_get_arguments(current, regs, args);
+		audit_syscall_entry(syscall, args[0], args[1], args[2], args[3]);
+	}
+}
+
+static long syscall_trace_enter(struct pt_regs *regs, long syscall,
+				unsigned long work)
+{
+	long ret = 0;
+
+	/*
+	 * Handle Syscall User Dispatch.  This must comes first, since
+	 * the ABI here can be something that doesn't make sense for
+	 * other syscall_work features.
+	 */
+	if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
+		if (syscall_user_dispatch(regs))
+			return -1L;
+	}
+
+	/* Handle ptrace */
+	if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
+		ret = ptrace_report_syscall_entry(regs);
+		if (ret || (work & SYSCALL_WORK_SYSCALL_EMU))
+			return -1L;
+	}
+
+	/* Do seccomp after ptrace, to catch any tracer changes. */
+	if (work & SYSCALL_WORK_SECCOMP) {
+		ret = __secure_computing(NULL);
+		if (ret == -1L)
+			return ret;
+	}
+
+	/* Either of the above might have changed the syscall number */
+	syscall = syscall_get_nr(current, regs);
+
+	if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT))
+		trace_sys_enter(regs, syscall);
+
+	syscall_enter_audit(regs, syscall);
+
+	return ret ? : syscall;
+}
+
+static __always_inline long
+__syscall_enter_from_user_work(struct pt_regs *regs, long syscall)
+{
+	unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
+
+	if (work & SYSCALL_WORK_ENTER)
+		syscall = syscall_trace_enter(regs, syscall, work);
+
+	return syscall;
+}
+
+long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall)
+{
+	return __syscall_enter_from_user_work(regs, syscall);
+}
+
+noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
+{
+	long ret;
+
+	__enter_from_user_mode(regs);
+
+	instrumentation_begin();
+	local_irq_enable();
+	ret = __syscall_enter_from_user_work(regs, syscall);
+	instrumentation_end();
+
+	return ret;
+}
+
+noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
+{
+	__enter_from_user_mode(regs);
+	instrumentation_begin();
+	local_irq_enable();
+	instrumentation_end();
+}
+
+/* See comment for exit_to_user_mode() in entry-common.h */
+static __always_inline void __exit_to_user_mode(void)
+{
+	instrumentation_begin();
+	trace_hardirqs_on_prepare();
+	lockdep_hardirqs_on_prepare();
+	instrumentation_end();
+
+	user_enter_irqoff();
+	arch_exit_to_user_mode();
+	lockdep_hardirqs_on(CALLER_ADDR0);
+}
+
+void noinstr exit_to_user_mode(void)
+{
+	__exit_to_user_mode();
+}
+
+/* Workaround to allow gradual conversion of architecture code */
+void __weak arch_do_signal_or_restart(struct pt_regs *regs) { }
+
+static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
+					    unsigned long ti_work)
+{
+	/*
+	 * Before returning to user space ensure that all pending work
+	 * items have been completed.
+	 */
+	while (ti_work & EXIT_TO_USER_MODE_WORK) {
+
+		local_irq_enable_exit_to_user(ti_work);
+
+		if (ti_work & _TIF_NEED_RESCHED)
+			schedule();
+
+		if (ti_work & _TIF_UPROBE)
+			uprobe_notify_resume(regs);
+
+		if (ti_work & _TIF_PATCH_PENDING)
+			klp_update_patch_state(current);
+
+		if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
+			arch_do_signal_or_restart(regs);
+
+		if (ti_work & _TIF_NOTIFY_RESUME)
+			resume_user_mode_work(regs);
+
+		/* Architecture specific TIF work */
+		arch_exit_to_user_mode_work(regs, ti_work);
+
+		/*
+		 * Disable interrupts and reevaluate the work flags as they
+		 * might have changed while interrupts and preemption was
+		 * enabled above.
+		 */
+		local_irq_disable_exit_to_user();
+
+		/* Check if any of the above work has queued a deferred wakeup */
+		tick_nohz_user_enter_prepare();
+
+		ti_work = read_thread_flags();
+	}
+
+	/* Return the latest work state for arch_exit_to_user_mode() */
+	return ti_work;
+}
+
+static void exit_to_user_mode_prepare(struct pt_regs *regs)
+{
+	unsigned long ti_work;
+
+	lockdep_assert_irqs_disabled();
+
+	/* Flush pending rcuog wakeup before the last need_resched() check */
+	tick_nohz_user_enter_prepare();
+
+	ti_work = read_thread_flags();
+	if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK))
+		ti_work = exit_to_user_mode_loop(regs, ti_work);
+
+	arch_exit_to_user_mode_prepare(regs, ti_work);
+
+	/* Ensure that the address limit is intact and no locks are held */
+	addr_limit_user_check();
+	kmap_assert_nomap();
+	lockdep_assert_irqs_disabled();
+	lockdep_sys_exit();
+}
+
+/*
+ * If SYSCALL_EMU is set, then the only reason to report is when
+ * SINGLESTEP is set (i.e. PTRACE_SYSEMU_SINGLESTEP).  This syscall
+ * instruction has been already reported in syscall_enter_from_user_mode().
+ */
+static inline bool report_single_step(unsigned long work)
+{
+	if (work & SYSCALL_WORK_SYSCALL_EMU)
+		return false;
+
+	return work & SYSCALL_WORK_SYSCALL_EXIT_TRAP;
+}
+
+static void syscall_exit_work(struct pt_regs *regs, unsigned long work)
+{
+	bool step;
+
+	/*
+	 * If the syscall was rolled back due to syscall user dispatching,
+	 * then the tracers below are not invoked for the same reason as
+	 * the entry side was not invoked in syscall_trace_enter(): The ABI
+	 * of these syscalls is unknown.
+	 */
+	if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
+		if (unlikely(current->syscall_dispatch.on_dispatch)) {
+			current->syscall_dispatch.on_dispatch = false;
+			return;
+		}
+	}
+
+	audit_syscall_exit(regs);
+
+	if (work & SYSCALL_WORK_SYSCALL_TRACEPOINT)
+		trace_sys_exit(regs, syscall_get_return_value(current, regs));
+
+	step = report_single_step(work);
+	if (step || work & SYSCALL_WORK_SYSCALL_TRACE)
+		ptrace_report_syscall_exit(regs, step);
+}
+
+/*
+ * Syscall specific exit to user mode preparation. Runs with interrupts
+ * enabled.
+ */
+static void syscall_exit_to_user_mode_prepare(struct pt_regs *regs)
+{
+	unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
+	unsigned long nr = syscall_get_nr(current, regs);
+
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
+
+	if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
+		if (WARN(irqs_disabled(), "syscall %lu left IRQs disabled", nr))
+			local_irq_enable();
+	}
+
+	rseq_syscall(regs);
+
+	/*
+	 * Do one-time syscall specific work. If these work items are
+	 * enabled, we want to run them exactly once per syscall exit with
+	 * interrupts enabled.
+	 */
+	if (unlikely(work & SYSCALL_WORK_EXIT))
+		syscall_exit_work(regs, work);
+}
+
+static __always_inline void __syscall_exit_to_user_mode_work(struct pt_regs *regs)
+{
+	syscall_exit_to_user_mode_prepare(regs);
+	local_irq_disable_exit_to_user();
+	exit_to_user_mode_prepare(regs);
+}
+
+void syscall_exit_to_user_mode_work(struct pt_regs *regs)
+{
+	__syscall_exit_to_user_mode_work(regs);
+}
+
+__visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs)
+{
+	instrumentation_begin();
+	__syscall_exit_to_user_mode_work(regs);
+	instrumentation_end();
+	__exit_to_user_mode();
+}
+
+noinstr void irqentry_enter_from_user_mode(struct pt_regs *regs)
+{
+	__enter_from_user_mode(regs);
+}
+
+noinstr void irqentry_exit_to_user_mode(struct pt_regs *regs)
+{
+	instrumentation_begin();
+	exit_to_user_mode_prepare(regs);
+	instrumentation_end();
+	__exit_to_user_mode();
+}
+
+noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)
+{
+	irqentry_state_t ret = {
+		.exit_rcu = false,
+	};
+
+	if (user_mode(regs)) {
+		irqentry_enter_from_user_mode(regs);
+		return ret;
+	}
+
+	/*
+	 * If this entry hit the idle task invoke ct_irq_enter() whether
+	 * RCU is watching or not.
+	 *
+	 * Interrupts can nest when the first interrupt invokes softirq
+	 * processing on return which enables interrupts.
+	 *
+	 * Scheduler ticks in the idle task can mark quiescent state and
+	 * terminate a grace period, if and only if the timer interrupt is
+	 * not nested into another interrupt.
+	 *
+	 * Checking for rcu_is_watching() here would prevent the nesting
+	 * interrupt to invoke ct_irq_enter(). If that nested interrupt is
+	 * the tick then rcu_flavor_sched_clock_irq() would wrongfully
+	 * assume that it is the first interrupt and eventually claim
+	 * quiescent state and end grace periods prematurely.
+	 *
+	 * Unconditionally invoke ct_irq_enter() so RCU state stays
+	 * consistent.
+	 *
+	 * TINY_RCU does not support EQS, so let the compiler eliminate
+	 * this part when enabled.
+	 */
+	if (!IS_ENABLED(CONFIG_TINY_RCU) && is_idle_task(current)) {
+		/*
+		 * If RCU is not watching then the same careful
+		 * sequence vs. lockdep and tracing is required
+		 * as in irqentry_enter_from_user_mode().
+		 */
+		lockdep_hardirqs_off(CALLER_ADDR0);
+		ct_irq_enter();
+		instrumentation_begin();
+		kmsan_unpoison_entry_regs(regs);
+		trace_hardirqs_off_finish();
+		instrumentation_end();
+
+		ret.exit_rcu = true;
+		return ret;
+	}
+
+	/*
+	 * If RCU is watching then RCU only wants to check whether it needs
+	 * to restart the tick in NOHZ mode. rcu_irq_enter_check_tick()
+	 * already contains a warning when RCU is not watching, so no point
+	 * in having another one here.
+	 */
+	lockdep_hardirqs_off(CALLER_ADDR0);
+	instrumentation_begin();
+	kmsan_unpoison_entry_regs(regs);
+	rcu_irq_enter_check_tick();
+	trace_hardirqs_off_finish();
+	instrumentation_end();
+
+	return ret;
+}
+
+void raw_irqentry_exit_cond_resched(void)
+{
+	if (!preempt_count()) {
+		/* Sanity check RCU and thread stack */
+		rcu_irq_exit_check_preempt();
+		if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
+			WARN_ON_ONCE(!on_thread_stack());
+		if (need_resched())
+			preempt_schedule_irq();
+	}
+}
+#ifdef CONFIG_PREEMPT_DYNAMIC
+#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
+DEFINE_STATIC_CALL(irqentry_exit_cond_resched, raw_irqentry_exit_cond_resched);
+#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
+DEFINE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
+void dynamic_irqentry_exit_cond_resched(void)
+{
+	if (!static_branch_unlikely(&sk_dynamic_irqentry_exit_cond_resched))
+		return;
+	raw_irqentry_exit_cond_resched();
+}
+#endif
+#endif
+
+noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state)
+{
+	lockdep_assert_irqs_disabled();
+
+	/* Check whether this returns to user mode */
+	if (user_mode(regs)) {
+		irqentry_exit_to_user_mode(regs);
+	} else if (!regs_irqs_disabled(regs)) {
+		/*
+		 * If RCU was not watching on entry this needs to be done
+		 * carefully and needs the same ordering of lockdep/tracing
+		 * and RCU as the return to user mode path.
+		 */
+		if (state.exit_rcu) {
+			instrumentation_begin();
+			/* Tell the tracer that IRET will enable interrupts */
+			trace_hardirqs_on_prepare();
+			lockdep_hardirqs_on_prepare();
+			instrumentation_end();
+			ct_irq_exit();
+			lockdep_hardirqs_on(CALLER_ADDR0);
+			return;
+		}
+
+		instrumentation_begin();
+		if (IS_ENABLED(CONFIG_PREEMPTION))
+			irqentry_exit_cond_resched();
+
+		/* Covers both tracing and lockdep */
+		trace_hardirqs_on();
+		instrumentation_end();
+	} else {
+		/*
+		 * IRQ flags state is correct already. Just tell RCU if it
+		 * was not watching on entry.
+		 */
+		if (state.exit_rcu)
+			ct_irq_exit();
+	}
+}
+
+irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs)
+{
+	irqentry_state_t irq_state;
+
+	irq_state.lockdep = lockdep_hardirqs_enabled();
+
+	__nmi_enter();
+	lockdep_hardirqs_off(CALLER_ADDR0);
+	lockdep_hardirq_enter();
+	ct_nmi_enter();
+
+	instrumentation_begin();
+	kmsan_unpoison_entry_regs(regs);
+	trace_hardirqs_off_finish();
+	ftrace_nmi_enter();
+	instrumentation_end();
+
+	return irq_state;
+}
+
+void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_state)
+{
+	instrumentation_begin();
+	ftrace_nmi_exit();
+	if (irq_state.lockdep) {
+		trace_hardirqs_on_prepare();
+		lockdep_hardirqs_on_prepare();
+	}
+	instrumentation_end();
+
+	ct_nmi_exit();
+	lockdep_hardirq_exit();
+	if (irq_state.lockdep)
+		lockdep_hardirqs_on(CALLER_ADDR0);
+	__nmi_exit();
+}
diff --git a/kernel/entry/common.h b/kernel/entry/common.h
new file mode 100644
index 000000000..f6e6d02f0
--- /dev/null
+++ b/kernel/entry/common.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _COMMON_H
+#define _COMMON_H
+
+bool syscall_user_dispatch(struct pt_regs *regs);
+
+#endif
diff --git a/kernel/entry/kvm.c b/kernel/entry/kvm.c
new file mode 100644
index 000000000..2e0f75bcb
--- /dev/null
+++ b/kernel/entry/kvm.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/entry-kvm.h>
+#include <linux/kvm_host.h>
+
+static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work)
+{
+	do {
+		int ret;
+
+		if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
+			kvm_handle_signal_exit(vcpu);
+			return -EINTR;
+		}
+
+		if (ti_work & _TIF_NEED_RESCHED)
+			schedule();
+
+		if (ti_work & _TIF_NOTIFY_RESUME)
+			resume_user_mode_work(NULL);
+
+		ret = arch_xfer_to_guest_mode_handle_work(vcpu, ti_work);
+		if (ret)
+			return ret;
+
+		ti_work = read_thread_flags();
+	} while (ti_work & XFER_TO_GUEST_MODE_WORK || need_resched());
+	return 0;
+}
+
+int xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu)
+{
+	unsigned long ti_work;
+
+	/*
+	 * This is invoked from the outer guest loop with interrupts and
+	 * preemption enabled.
+	 *
+	 * KVM invokes xfer_to_guest_mode_work_pending() with interrupts
+	 * disabled in the inner loop before going into guest mode. No need
+	 * to disable interrupts here.
+	 */
+	ti_work = read_thread_flags();
+	if (!(ti_work & XFER_TO_GUEST_MODE_WORK))
+		return 0;
+
+	return xfer_to_guest_mode_work(vcpu, ti_work);
+}
+EXPORT_SYMBOL_GPL(xfer_to_guest_mode_handle_work);
diff --git a/kernel/entry/syscall_user_dispatch.c b/kernel/entry/syscall_user_dispatch.c
new file mode 100644
index 000000000..0b6379adf
--- /dev/null
+++ b/kernel/entry/syscall_user_dispatch.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Collabora Ltd.
+ */
+#include <linux/sched.h>
+#include <linux/prctl.h>
+#include <linux/syscall_user_dispatch.h>
+#include <linux/uaccess.h>
+#include <linux/signal.h>
+#include <linux/elf.h>
+
+#include <linux/sched/signal.h>
+#include <linux/sched/task_stack.h>
+
+#include <asm/syscall.h>
+
+#include "common.h"
+
+static void trigger_sigsys(struct pt_regs *regs)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = SIGSYS;
+	info.si_code = SYS_USER_DISPATCH;
+	info.si_call_addr = (void __user *)KSTK_EIP(current);
+	info.si_errno = 0;
+	info.si_arch = syscall_get_arch(current);
+	info.si_syscall = syscall_get_nr(current, regs);
+
+	force_sig_info(&info);
+}
+
+bool syscall_user_dispatch(struct pt_regs *regs)
+{
+	struct syscall_user_dispatch *sd = &current->syscall_dispatch;
+	char state;
+
+	if (likely(instruction_pointer(regs) - sd->offset < sd->len))
+		return false;
+
+	if (unlikely(arch_syscall_is_vdso_sigreturn(regs)))
+		return false;
+
+	if (likely(sd->selector)) {
+		/*
+		 * access_ok() is performed once, at prctl time, when
+		 * the selector is loaded by userspace.
+		 */
+		if (unlikely(__get_user(state, sd->selector))) {
+			force_exit_sig(SIGSEGV);
+			return true;
+		}
+
+		if (likely(state == SYSCALL_DISPATCH_FILTER_ALLOW))
+			return false;
+
+		if (state != SYSCALL_DISPATCH_FILTER_BLOCK) {
+			force_exit_sig(SIGSYS);
+			return true;
+		}
+	}
+
+	sd->on_dispatch = true;
+	syscall_rollback(current, regs);
+	trigger_sigsys(regs);
+
+	return true;
+}
+
+int set_syscall_user_dispatch(unsigned long mode, unsigned long offset,
+			      unsigned long len, char __user *selector)
+{
+	switch (mode) {
+	case PR_SYS_DISPATCH_OFF:
+		if (offset || len || selector)
+			return -EINVAL;
+		break;
+	case PR_SYS_DISPATCH_ON:
+		/*
+		 * Validate the direct dispatcher region just for basic
+		 * sanity against overflow and a 0-sized dispatcher
+		 * region.  If the user is able to submit a syscall from
+		 * an address, that address is obviously valid.
+		 */
+		if (offset && offset + len <= offset)
+			return -EINVAL;
+
+		if (selector && !access_ok(selector, sizeof(*selector)))
+			return -EFAULT;
+
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	current->syscall_dispatch.selector = selector;
+	current->syscall_dispatch.offset = offset;
+	current->syscall_dispatch.len = len;
+	current->syscall_dispatch.on_dispatch = false;
+
+	if (mode == PR_SYS_DISPATCH_ON)
+		set_syscall_work(SYSCALL_USER_DISPATCH);
+	else
+		clear_syscall_work(SYSCALL_USER_DISPATCH);
+
+	return 0;
+}
diff --git a/kernel/events/Makefile b/kernel/events/Makefile
new file mode 100644
index 000000000..91a62f566
--- /dev/null
+++ b/kernel/events/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y := core.o ring_buffer.o callchain.o
+
+obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
+obj-$(CONFIG_HW_BREAKPOINT_KUNIT_TEST) += hw_breakpoint_test.o
+obj-$(CONFIG_UPROBES) += uprobes.o
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
new file mode 100644
index 000000000..1273be843
--- /dev/null
+++ b/kernel/events/callchain.c
@@ -0,0 +1,253 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Performance events callchain code, extracted from core.c:
+ *
+ *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
+ *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
+ *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
+ *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
+ */
+
+#include <linux/perf_event.h>
+#include <linux/slab.h>
+#include <linux/sched/task_stack.h>
+
+#include "internal.h"
+
+struct callchain_cpus_entries {
+	struct rcu_head			rcu_head;
+	struct perf_callchain_entry	*cpu_entries[];
+};
+
+int sysctl_perf_event_max_stack __read_mostly = PERF_MAX_STACK_DEPTH;
+int sysctl_perf_event_max_contexts_per_stack __read_mostly = PERF_MAX_CONTEXTS_PER_STACK;
+
+static inline size_t perf_callchain_entry__sizeof(void)
+{
+	return (sizeof(struct perf_callchain_entry) +
+		sizeof(__u64) * (sysctl_perf_event_max_stack +
+				 sysctl_perf_event_max_contexts_per_stack));
+}
+
+static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
+static atomic_t nr_callchain_events;
+static DEFINE_MUTEX(callchain_mutex);
+static struct callchain_cpus_entries *callchain_cpus_entries;
+
+
+__weak void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
+				  struct pt_regs *regs)
+{
+}
+
+__weak void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
+				struct pt_regs *regs)
+{
+}
+
+static void release_callchain_buffers_rcu(struct rcu_head *head)
+{
+	struct callchain_cpus_entries *entries;
+	int cpu;
+
+	entries = container_of(head, struct callchain_cpus_entries, rcu_head);
+
+	for_each_possible_cpu(cpu)
+		kfree(entries->cpu_entries[cpu]);
+
+	kfree(entries);
+}
+
+static void release_callchain_buffers(void)
+{
+	struct callchain_cpus_entries *entries;
+
+	entries = callchain_cpus_entries;
+	RCU_INIT_POINTER(callchain_cpus_entries, NULL);
+	call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
+}
+
+static int alloc_callchain_buffers(void)
+{
+	int cpu;
+	int size;
+	struct callchain_cpus_entries *entries;
+
+	/*
+	 * We can't use the percpu allocation API for data that can be
+	 * accessed from NMI. Use a temporary manual per cpu allocation
+	 * until that gets sorted out.
+	 */
+	size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
+
+	entries = kzalloc(size, GFP_KERNEL);
+	if (!entries)
+		return -ENOMEM;
+
+	size = perf_callchain_entry__sizeof() * PERF_NR_CONTEXTS;
+
+	for_each_possible_cpu(cpu) {
+		entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
+							 cpu_to_node(cpu));
+		if (!entries->cpu_entries[cpu])
+			goto fail;
+	}
+
+	rcu_assign_pointer(callchain_cpus_entries, entries);
+
+	return 0;
+
+fail:
+	for_each_possible_cpu(cpu)
+		kfree(entries->cpu_entries[cpu]);
+	kfree(entries);
+
+	return -ENOMEM;
+}
+
+int get_callchain_buffers(int event_max_stack)
+{
+	int err = 0;
+	int count;
+
+	mutex_lock(&callchain_mutex);
+
+	count = atomic_inc_return(&nr_callchain_events);
+	if (WARN_ON_ONCE(count < 1)) {
+		err = -EINVAL;
+		goto exit;
+	}
+
+	/*
+	 * If requesting per event more than the global cap,
+	 * return a different error to help userspace figure
+	 * this out.
+	 *
+	 * And also do it here so that we have &callchain_mutex held.
+	 */
+	if (event_max_stack > sysctl_perf_event_max_stack) {
+		err = -EOVERFLOW;
+		goto exit;
+	}
+
+	if (count == 1)
+		err = alloc_callchain_buffers();
+exit:
+	if (err)
+		atomic_dec(&nr_callchain_events);
+
+	mutex_unlock(&callchain_mutex);
+
+	return err;
+}
+
+void put_callchain_buffers(void)
+{
+	if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
+		release_callchain_buffers();
+		mutex_unlock(&callchain_mutex);
+	}
+}
+
+struct perf_callchain_entry *get_callchain_entry(int *rctx)
+{
+	int cpu;
+	struct callchain_cpus_entries *entries;
+
+	*rctx = get_recursion_context(this_cpu_ptr(callchain_recursion));
+	if (*rctx == -1)
+		return NULL;
+
+	entries = rcu_dereference(callchain_cpus_entries);
+	if (!entries) {
+		put_recursion_context(this_cpu_ptr(callchain_recursion), *rctx);
+		return NULL;
+	}
+
+	cpu = smp_processor_id();
+
+	return (((void *)entries->cpu_entries[cpu]) +
+		(*rctx * perf_callchain_entry__sizeof()));
+}
+
+void
+put_callchain_entry(int rctx)
+{
+	put_recursion_context(this_cpu_ptr(callchain_recursion), rctx);
+}
+
+struct perf_callchain_entry *
+get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
+		   u32 max_stack, bool crosstask, bool add_mark)
+{
+	struct perf_callchain_entry *entry;
+	struct perf_callchain_entry_ctx ctx;
+	int rctx;
+
+	entry = get_callchain_entry(&rctx);
+	if (!entry)
+		return NULL;
+
+	ctx.entry     = entry;
+	ctx.max_stack = max_stack;
+	ctx.nr	      = entry->nr = init_nr;
+	ctx.contexts       = 0;
+	ctx.contexts_maxed = false;
+
+	if (kernel && !user_mode(regs)) {
+		if (add_mark)
+			perf_callchain_store_context(&ctx, PERF_CONTEXT_KERNEL);
+		perf_callchain_kernel(&ctx, regs);
+	}
+
+	if (user) {
+		if (!user_mode(regs)) {
+			if  (current->mm)
+				regs = task_pt_regs(current);
+			else
+				regs = NULL;
+		}
+
+		if (regs) {
+			if (crosstask)
+				goto exit_put;
+
+			if (add_mark)
+				perf_callchain_store_context(&ctx, PERF_CONTEXT_USER);
+
+			perf_callchain_user(&ctx, regs);
+		}
+	}
+
+exit_put:
+	put_callchain_entry(rctx);
+
+	return entry;
+}
+
+/*
+ * Used for sysctl_perf_event_max_stack and
+ * sysctl_perf_event_max_contexts_per_stack.
+ */
+int perf_event_max_stack_handler(struct ctl_table *table, int write,
+				 void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int *value = table->data;
+	int new_value = *value, ret;
+	struct ctl_table new_table = *table;
+
+	new_table.data = &new_value;
+	ret = proc_dointvec_minmax(&new_table, write, buffer, lenp, ppos);
+	if (ret || !write)
+		return ret;
+
+	mutex_lock(&callchain_mutex);
+	if (atomic_read(&nr_callchain_events))
+		ret = -EBUSY;
+	else
+		*value = new_value;
+
+	mutex_unlock(&callchain_mutex);
+
+	return ret;
+}
diff --git a/kernel/events/core.c b/kernel/events/core.c
new file mode 100644
index 000000000..8c7d2f4f5
--- /dev/null
+++ b/kernel/events/core.c
@@ -0,0 +1,13761 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Performance events core code:
+ *
+ *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
+ *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
+ *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
+ *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/cpu.h>
+#include <linux/smp.h>
+#include <linux/idr.h>
+#include <linux/file.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/hash.h>
+#include <linux/tick.h>
+#include <linux/sysfs.h>
+#include <linux/dcache.h>
+#include <linux/percpu.h>
+#include <linux/ptrace.h>
+#include <linux/reboot.h>
+#include <linux/vmstat.h>
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/vmalloc.h>
+#include <linux/hardirq.h>
+#include <linux/hugetlb.h>
+#include <linux/rculist.h>
+#include <linux/uaccess.h>
+#include <linux/syscalls.h>
+#include <linux/anon_inodes.h>
+#include <linux/kernel_stat.h>
+#include <linux/cgroup.h>
+#include <linux/perf_event.h>
+#include <linux/trace_events.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/mm_types.h>
+#include <linux/module.h>
+#include <linux/mman.h>
+#include <linux/compat.h>
+#include <linux/bpf.h>
+#include <linux/filter.h>
+#include <linux/namei.h>
+#include <linux/parser.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/mm.h>
+#include <linux/proc_ns.h>
+#include <linux/mount.h>
+#include <linux/min_heap.h>
+#include <linux/highmem.h>
+#include <linux/pgtable.h>
+#include <linux/buildid.h>
+#include <linux/task_work.h>
+
+#include "internal.h"
+
+#include <asm/irq_regs.h>
+
+typedef int (*remote_function_f)(void *);
+
+struct remote_function_call {
+	struct task_struct	*p;
+	remote_function_f	func;
+	void			*info;
+	int			ret;
+};
+
+static void remote_function(void *data)
+{
+	struct remote_function_call *tfc = data;
+	struct task_struct *p = tfc->p;
+
+	if (p) {
+		/* -EAGAIN */
+		if (task_cpu(p) != smp_processor_id())
+			return;
+
+		/*
+		 * Now that we're on right CPU with IRQs disabled, we can test
+		 * if we hit the right task without races.
+		 */
+
+		tfc->ret = -ESRCH; /* No such (running) process */
+		if (p != current)
+			return;
+	}
+
+	tfc->ret = tfc->func(tfc->info);
+}
+
+/**
+ * task_function_call - call a function on the cpu on which a task runs
+ * @p:		the task to evaluate
+ * @func:	the function to be called
+ * @info:	the function call argument
+ *
+ * Calls the function @func when the task is currently running. This might
+ * be on the current CPU, which just calls the function directly.  This will
+ * retry due to any failures in smp_call_function_single(), such as if the
+ * task_cpu() goes offline concurrently.
+ *
+ * returns @func return value or -ESRCH or -ENXIO when the process isn't running
+ */
+static int
+task_function_call(struct task_struct *p, remote_function_f func, void *info)
+{
+	struct remote_function_call data = {
+		.p	= p,
+		.func	= func,
+		.info	= info,
+		.ret	= -EAGAIN,
+	};
+	int ret;
+
+	for (;;) {
+		ret = smp_call_function_single(task_cpu(p), remote_function,
+					       &data, 1);
+		if (!ret)
+			ret = data.ret;
+
+		if (ret != -EAGAIN)
+			break;
+
+		cond_resched();
+	}
+
+	return ret;
+}
+
+/**
+ * cpu_function_call - call a function on the cpu
+ * @cpu:	target cpu to queue this function
+ * @func:	the function to be called
+ * @info:	the function call argument
+ *
+ * Calls the function @func on the remote cpu.
+ *
+ * returns: @func return value or -ENXIO when the cpu is offline
+ */
+static int cpu_function_call(int cpu, remote_function_f func, void *info)
+{
+	struct remote_function_call data = {
+		.p	= NULL,
+		.func	= func,
+		.info	= info,
+		.ret	= -ENXIO, /* No such CPU */
+	};
+
+	smp_call_function_single(cpu, remote_function, &data, 1);
+
+	return data.ret;
+}
+
+static inline struct perf_cpu_context *
+__get_cpu_context(struct perf_event_context *ctx)
+{
+	return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
+}
+
+static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
+			  struct perf_event_context *ctx)
+{
+	raw_spin_lock(&cpuctx->ctx.lock);
+	if (ctx)
+		raw_spin_lock(&ctx->lock);
+}
+
+static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
+			    struct perf_event_context *ctx)
+{
+	if (ctx)
+		raw_spin_unlock(&ctx->lock);
+	raw_spin_unlock(&cpuctx->ctx.lock);
+}
+
+#define TASK_TOMBSTONE ((void *)-1L)
+
+static bool is_kernel_event(struct perf_event *event)
+{
+	return READ_ONCE(event->owner) == TASK_TOMBSTONE;
+}
+
+/*
+ * On task ctx scheduling...
+ *
+ * When !ctx->nr_events a task context will not be scheduled. This means
+ * we can disable the scheduler hooks (for performance) without leaving
+ * pending task ctx state.
+ *
+ * This however results in two special cases:
+ *
+ *  - removing the last event from a task ctx; this is relatively straight
+ *    forward and is done in __perf_remove_from_context.
+ *
+ *  - adding the first event to a task ctx; this is tricky because we cannot
+ *    rely on ctx->is_active and therefore cannot use event_function_call().
+ *    See perf_install_in_context().
+ *
+ * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
+ */
+
+typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
+			struct perf_event_context *, void *);
+
+struct event_function_struct {
+	struct perf_event *event;
+	event_f func;
+	void *data;
+};
+
+static int event_function(void *info)
+{
+	struct event_function_struct *efs = info;
+	struct perf_event *event = efs->event;
+	struct perf_event_context *ctx = event->ctx;
+	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+	struct perf_event_context *task_ctx = cpuctx->task_ctx;
+	int ret = 0;
+
+	lockdep_assert_irqs_disabled();
+
+	perf_ctx_lock(cpuctx, task_ctx);
+	/*
+	 * Since we do the IPI call without holding ctx->lock things can have
+	 * changed, double check we hit the task we set out to hit.
+	 */
+	if (ctx->task) {
+		if (ctx->task != current) {
+			ret = -ESRCH;
+			goto unlock;
+		}
+
+		/*
+		 * We only use event_function_call() on established contexts,
+		 * and event_function() is only ever called when active (or
+		 * rather, we'll have bailed in task_function_call() or the
+		 * above ctx->task != current test), therefore we must have
+		 * ctx->is_active here.
+		 */
+		WARN_ON_ONCE(!ctx->is_active);
+		/*
+		 * And since we have ctx->is_active, cpuctx->task_ctx must
+		 * match.
+		 */
+		WARN_ON_ONCE(task_ctx != ctx);
+	} else {
+		WARN_ON_ONCE(&cpuctx->ctx != ctx);
+	}
+
+	efs->func(event, cpuctx, ctx, efs->data);
+unlock:
+	perf_ctx_unlock(cpuctx, task_ctx);
+
+	return ret;
+}
+
+static void event_function_call(struct perf_event *event, event_f func, void *data)
+{
+	struct perf_event_context *ctx = event->ctx;
+	struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
+	struct event_function_struct efs = {
+		.event = event,
+		.func = func,
+		.data = data,
+	};
+
+	if (!event->parent) {
+		/*
+		 * If this is a !child event, we must hold ctx::mutex to
+		 * stabilize the event->ctx relation. See
+		 * perf_event_ctx_lock().
+		 */
+		lockdep_assert_held(&ctx->mutex);
+	}
+
+	if (!task) {
+		cpu_function_call(event->cpu, event_function, &efs);
+		return;
+	}
+
+	if (task == TASK_TOMBSTONE)
+		return;
+
+again:
+	if (!task_function_call(task, event_function, &efs))
+		return;
+
+	raw_spin_lock_irq(&ctx->lock);
+	/*
+	 * Reload the task pointer, it might have been changed by
+	 * a concurrent perf_event_context_sched_out().
+	 */
+	task = ctx->task;
+	if (task == TASK_TOMBSTONE) {
+		raw_spin_unlock_irq(&ctx->lock);
+		return;
+	}
+	if (ctx->is_active) {
+		raw_spin_unlock_irq(&ctx->lock);
+		goto again;
+	}
+	func(event, NULL, ctx, data);
+	raw_spin_unlock_irq(&ctx->lock);
+}
+
+/*
+ * Similar to event_function_call() + event_function(), but hard assumes IRQs
+ * are already disabled and we're on the right CPU.
+ */
+static void event_function_local(struct perf_event *event, event_f func, void *data)
+{
+	struct perf_event_context *ctx = event->ctx;
+	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+	struct task_struct *task = READ_ONCE(ctx->task);
+	struct perf_event_context *task_ctx = NULL;
+
+	lockdep_assert_irqs_disabled();
+
+	if (task) {
+		if (task == TASK_TOMBSTONE)
+			return;
+
+		task_ctx = ctx;
+	}
+
+	perf_ctx_lock(cpuctx, task_ctx);
+
+	task = ctx->task;
+	if (task == TASK_TOMBSTONE)
+		goto unlock;
+
+	if (task) {
+		/*
+		 * We must be either inactive or active and the right task,
+		 * otherwise we're screwed, since we cannot IPI to somewhere
+		 * else.
+		 */
+		if (ctx->is_active) {
+			if (WARN_ON_ONCE(task != current))
+				goto unlock;
+
+			if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
+				goto unlock;
+		}
+	} else {
+		WARN_ON_ONCE(&cpuctx->ctx != ctx);
+	}
+
+	func(event, cpuctx, ctx, data);
+unlock:
+	perf_ctx_unlock(cpuctx, task_ctx);
+}
+
+#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
+		       PERF_FLAG_FD_OUTPUT  |\
+		       PERF_FLAG_PID_CGROUP |\
+		       PERF_FLAG_FD_CLOEXEC)
+
+/*
+ * branch priv levels that need permission checks
+ */
+#define PERF_SAMPLE_BRANCH_PERM_PLM \
+	(PERF_SAMPLE_BRANCH_KERNEL |\
+	 PERF_SAMPLE_BRANCH_HV)
+
+enum event_type_t {
+	EVENT_FLEXIBLE = 0x1,
+	EVENT_PINNED = 0x2,
+	EVENT_TIME = 0x4,
+	/* see ctx_resched() for details */
+	EVENT_CPU = 0x8,
+	EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
+};
+
+/*
+ * perf_sched_events : >0 events exist
+ * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
+ */
+
+static void perf_sched_delayed(struct work_struct *work);
+DEFINE_STATIC_KEY_FALSE(perf_sched_events);
+static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
+static DEFINE_MUTEX(perf_sched_mutex);
+static atomic_t perf_sched_count;
+
+static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
+static DEFINE_PER_CPU(int, perf_sched_cb_usages);
+static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
+
+static atomic_t nr_mmap_events __read_mostly;
+static atomic_t nr_comm_events __read_mostly;
+static atomic_t nr_namespaces_events __read_mostly;
+static atomic_t nr_task_events __read_mostly;
+static atomic_t nr_freq_events __read_mostly;
+static atomic_t nr_switch_events __read_mostly;
+static atomic_t nr_ksymbol_events __read_mostly;
+static atomic_t nr_bpf_events __read_mostly;
+static atomic_t nr_cgroup_events __read_mostly;
+static atomic_t nr_text_poke_events __read_mostly;
+static atomic_t nr_build_id_events __read_mostly;
+
+static LIST_HEAD(pmus);
+static DEFINE_MUTEX(pmus_lock);
+static struct srcu_struct pmus_srcu;
+static cpumask_var_t perf_online_mask;
+static struct kmem_cache *perf_event_cache;
+
+/*
+ * perf event paranoia level:
+ *  -1 - not paranoid at all
+ *   0 - disallow raw tracepoint access for unpriv
+ *   1 - disallow cpu events for unpriv
+ *   2 - disallow kernel profiling for unpriv
+ */
+int sysctl_perf_event_paranoid __read_mostly = 2;
+
+/* Minimum for 512 kiB + 1 user control page */
+int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
+
+/*
+ * max perf event sample rate
+ */
+#define DEFAULT_MAX_SAMPLE_RATE		100000
+#define DEFAULT_SAMPLE_PERIOD_NS	(NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
+#define DEFAULT_CPU_TIME_MAX_PERCENT	25
+
+int sysctl_perf_event_sample_rate __read_mostly	= DEFAULT_MAX_SAMPLE_RATE;
+
+static int max_samples_per_tick __read_mostly	= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
+static int perf_sample_period_ns __read_mostly	= DEFAULT_SAMPLE_PERIOD_NS;
+
+static int perf_sample_allowed_ns __read_mostly =
+	DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
+
+static void update_perf_cpu_limits(void)
+{
+	u64 tmp = perf_sample_period_ns;
+
+	tmp *= sysctl_perf_cpu_time_max_percent;
+	tmp = div_u64(tmp, 100);
+	if (!tmp)
+		tmp = 1;
+
+	WRITE_ONCE(perf_sample_allowed_ns, tmp);
+}
+
+static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
+
+int perf_proc_update_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int ret;
+	int perf_cpu = sysctl_perf_cpu_time_max_percent;
+	/*
+	 * If throttling is disabled don't allow the write:
+	 */
+	if (write && (perf_cpu == 100 || perf_cpu == 0))
+		return -EINVAL;
+
+	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+	if (ret || !write)
+		return ret;
+
+	max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
+	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
+	update_perf_cpu_limits();
+
+	return 0;
+}
+
+int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
+
+int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+
+	if (ret || !write)
+		return ret;
+
+	if (sysctl_perf_cpu_time_max_percent == 100 ||
+	    sysctl_perf_cpu_time_max_percent == 0) {
+		printk(KERN_WARNING
+		       "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
+		WRITE_ONCE(perf_sample_allowed_ns, 0);
+	} else {
+		update_perf_cpu_limits();
+	}
+
+	return 0;
+}
+
+/*
+ * perf samples are done in some very critical code paths (NMIs).
+ * If they take too much CPU time, the system can lock up and not
+ * get any real work done.  This will drop the sample rate when
+ * we detect that events are taking too long.
+ */
+#define NR_ACCUMULATED_SAMPLES 128
+static DEFINE_PER_CPU(u64, running_sample_length);
+
+static u64 __report_avg;
+static u64 __report_allowed;
+
+static void perf_duration_warn(struct irq_work *w)
+{
+	printk_ratelimited(KERN_INFO
+		"perf: interrupt took too long (%lld > %lld), lowering "
+		"kernel.perf_event_max_sample_rate to %d\n",
+		__report_avg, __report_allowed,
+		sysctl_perf_event_sample_rate);
+}
+
+static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
+
+void perf_sample_event_took(u64 sample_len_ns)
+{
+	u64 max_len = READ_ONCE(perf_sample_allowed_ns);
+	u64 running_len;
+	u64 avg_len;
+	u32 max;
+
+	if (max_len == 0)
+		return;
+
+	/* Decay the counter by 1 average sample. */
+	running_len = __this_cpu_read(running_sample_length);
+	running_len -= running_len/NR_ACCUMULATED_SAMPLES;
+	running_len += sample_len_ns;
+	__this_cpu_write(running_sample_length, running_len);
+
+	/*
+	 * Note: this will be biased artifically low until we have
+	 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
+	 * from having to maintain a count.
+	 */
+	avg_len = running_len/NR_ACCUMULATED_SAMPLES;
+	if (avg_len <= max_len)
+		return;
+
+	__report_avg = avg_len;
+	__report_allowed = max_len;
+
+	/*
+	 * Compute a throttle threshold 25% below the current duration.
+	 */
+	avg_len += avg_len / 4;
+	max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
+	if (avg_len < max)
+		max /= (u32)avg_len;
+	else
+		max = 1;
+
+	WRITE_ONCE(perf_sample_allowed_ns, avg_len);
+	WRITE_ONCE(max_samples_per_tick, max);
+
+	sysctl_perf_event_sample_rate = max * HZ;
+	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
+
+	if (!irq_work_queue(&perf_duration_work)) {
+		early_printk("perf: interrupt took too long (%lld > %lld), lowering "
+			     "kernel.perf_event_max_sample_rate to %d\n",
+			     __report_avg, __report_allowed,
+			     sysctl_perf_event_sample_rate);
+	}
+}
+
+static atomic64_t perf_event_id;
+
+static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
+			      enum event_type_t event_type);
+
+static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
+			     enum event_type_t event_type);
+
+static void update_context_time(struct perf_event_context *ctx);
+static u64 perf_event_time(struct perf_event *event);
+
+void __weak perf_event_print_debug(void)	{ }
+
+static inline u64 perf_clock(void)
+{
+	return local_clock();
+}
+
+static inline u64 perf_event_clock(struct perf_event *event)
+{
+	return event->clock();
+}
+
+/*
+ * State based event timekeeping...
+ *
+ * The basic idea is to use event->state to determine which (if any) time
+ * fields to increment with the current delta. This means we only need to
+ * update timestamps when we change state or when they are explicitly requested
+ * (read).
+ *
+ * Event groups make things a little more complicated, but not terribly so. The
+ * rules for a group are that if the group leader is OFF the entire group is
+ * OFF, irrespecive of what the group member states are. This results in
+ * __perf_effective_state().
+ *
+ * A futher ramification is that when a group leader flips between OFF and
+ * !OFF, we need to update all group member times.
+ *
+ *
+ * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
+ * need to make sure the relevant context time is updated before we try and
+ * update our timestamps.
+ */
+
+static __always_inline enum perf_event_state
+__perf_effective_state(struct perf_event *event)
+{
+	struct perf_event *leader = event->group_leader;
+
+	if (leader->state <= PERF_EVENT_STATE_OFF)
+		return leader->state;
+
+	return event->state;
+}
+
+static __always_inline void
+__perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
+{
+	enum perf_event_state state = __perf_effective_state(event);
+	u64 delta = now - event->tstamp;
+
+	*enabled = event->total_time_enabled;
+	if (state >= PERF_EVENT_STATE_INACTIVE)
+		*enabled += delta;
+
+	*running = event->total_time_running;
+	if (state >= PERF_EVENT_STATE_ACTIVE)
+		*running += delta;
+}
+
+static void perf_event_update_time(struct perf_event *event)
+{
+	u64 now = perf_event_time(event);
+
+	__perf_update_times(event, now, &event->total_time_enabled,
+					&event->total_time_running);
+	event->tstamp = now;
+}
+
+static void perf_event_update_sibling_time(struct perf_event *leader)
+{
+	struct perf_event *sibling;
+
+	for_each_sibling_event(sibling, leader)
+		perf_event_update_time(sibling);
+}
+
+static void
+perf_event_set_state(struct perf_event *event, enum perf_event_state state)
+{
+	if (event->state == state)
+		return;
+
+	perf_event_update_time(event);
+	/*
+	 * If a group leader gets enabled/disabled all its siblings
+	 * are affected too.
+	 */
+	if ((event->state < 0) ^ (state < 0))
+		perf_event_update_sibling_time(event);
+
+	WRITE_ONCE(event->state, state);
+}
+
+/*
+ * UP store-release, load-acquire
+ */
+
+#define __store_release(ptr, val)					\
+do {									\
+	barrier();							\
+	WRITE_ONCE(*(ptr), (val));					\
+} while (0)
+
+#define __load_acquire(ptr)						\
+({									\
+	__unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr));	\
+	barrier();							\
+	___p;								\
+})
+
+#ifdef CONFIG_CGROUP_PERF
+
+static inline bool
+perf_cgroup_match(struct perf_event *event)
+{
+	struct perf_event_context *ctx = event->ctx;
+	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+
+	/* @event doesn't care about cgroup */
+	if (!event->cgrp)
+		return true;
+
+	/* wants specific cgroup scope but @cpuctx isn't associated with any */
+	if (!cpuctx->cgrp)
+		return false;
+
+	/*
+	 * Cgroup scoping is recursive.  An event enabled for a cgroup is
+	 * also enabled for all its descendant cgroups.  If @cpuctx's
+	 * cgroup is a descendant of @event's (the test covers identity
+	 * case), it's a match.
+	 */
+	return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
+				    event->cgrp->css.cgroup);
+}
+
+static inline void perf_detach_cgroup(struct perf_event *event)
+{
+	css_put(&event->cgrp->css);
+	event->cgrp = NULL;
+}
+
+static inline int is_cgroup_event(struct perf_event *event)
+{
+	return event->cgrp != NULL;
+}
+
+static inline u64 perf_cgroup_event_time(struct perf_event *event)
+{
+	struct perf_cgroup_info *t;
+
+	t = per_cpu_ptr(event->cgrp->info, event->cpu);
+	return t->time;
+}
+
+static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
+{
+	struct perf_cgroup_info *t;
+
+	t = per_cpu_ptr(event->cgrp->info, event->cpu);
+	if (!__load_acquire(&t->active))
+		return t->time;
+	now += READ_ONCE(t->timeoffset);
+	return now;
+}
+
+static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv)
+{
+	if (adv)
+		info->time += now - info->timestamp;
+	info->timestamp = now;
+	/*
+	 * see update_context_time()
+	 */
+	WRITE_ONCE(info->timeoffset, info->time - info->timestamp);
+}
+
+static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final)
+{
+	struct perf_cgroup *cgrp = cpuctx->cgrp;
+	struct cgroup_subsys_state *css;
+	struct perf_cgroup_info *info;
+
+	if (cgrp) {
+		u64 now = perf_clock();
+
+		for (css = &cgrp->css; css; css = css->parent) {
+			cgrp = container_of(css, struct perf_cgroup, css);
+			info = this_cpu_ptr(cgrp->info);
+
+			__update_cgrp_time(info, now, true);
+			if (final)
+				__store_release(&info->active, 0);
+		}
+	}
+}
+
+static inline void update_cgrp_time_from_event(struct perf_event *event)
+{
+	struct perf_cgroup_info *info;
+
+	/*
+	 * ensure we access cgroup data only when needed and
+	 * when we know the cgroup is pinned (css_get)
+	 */
+	if (!is_cgroup_event(event))
+		return;
+
+	info = this_cpu_ptr(event->cgrp->info);
+	/*
+	 * Do not update time when cgroup is not active
+	 */
+	if (info->active)
+		__update_cgrp_time(info, perf_clock(), true);
+}
+
+static inline void
+perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
+{
+	struct perf_event_context *ctx = &cpuctx->ctx;
+	struct perf_cgroup *cgrp = cpuctx->cgrp;
+	struct perf_cgroup_info *info;
+	struct cgroup_subsys_state *css;
+
+	/*
+	 * ctx->lock held by caller
+	 * ensure we do not access cgroup data
+	 * unless we have the cgroup pinned (css_get)
+	 */
+	if (!cgrp)
+		return;
+
+	WARN_ON_ONCE(!ctx->nr_cgroups);
+
+	for (css = &cgrp->css; css; css = css->parent) {
+		cgrp = container_of(css, struct perf_cgroup, css);
+		info = this_cpu_ptr(cgrp->info);
+		__update_cgrp_time(info, ctx->timestamp, false);
+		__store_release(&info->active, 1);
+	}
+}
+
+static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
+
+/*
+ * reschedule events based on the cgroup constraint of task.
+ */
+static void perf_cgroup_switch(struct task_struct *task)
+{
+	struct perf_cgroup *cgrp;
+	struct perf_cpu_context *cpuctx, *tmp;
+	struct list_head *list;
+	unsigned long flags;
+
+	/*
+	 * Disable interrupts and preemption to avoid this CPU's
+	 * cgrp_cpuctx_entry to change under us.
+	 */
+	local_irq_save(flags);
+
+	cgrp = perf_cgroup_from_task(task, NULL);
+
+	list = this_cpu_ptr(&cgrp_cpuctx_list);
+	list_for_each_entry_safe(cpuctx, tmp, list, cgrp_cpuctx_entry) {
+		WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
+		if (READ_ONCE(cpuctx->cgrp) == cgrp)
+			continue;
+
+		perf_ctx_lock(cpuctx, cpuctx->task_ctx);
+		perf_pmu_disable(cpuctx->ctx.pmu);
+
+		cpu_ctx_sched_out(cpuctx, EVENT_ALL);
+		/*
+		 * must not be done before ctxswout due
+		 * to update_cgrp_time_from_cpuctx() in
+		 * ctx_sched_out()
+		 */
+		cpuctx->cgrp = cgrp;
+		/*
+		 * set cgrp before ctxsw in to allow
+		 * perf_cgroup_set_timestamp() in ctx_sched_in()
+		 * to not have to pass task around
+		 */
+		cpu_ctx_sched_in(cpuctx, EVENT_ALL);
+
+		perf_pmu_enable(cpuctx->ctx.pmu);
+		perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
+	}
+
+	local_irq_restore(flags);
+}
+
+static int perf_cgroup_ensure_storage(struct perf_event *event,
+				struct cgroup_subsys_state *css)
+{
+	struct perf_cpu_context *cpuctx;
+	struct perf_event **storage;
+	int cpu, heap_size, ret = 0;
+
+	/*
+	 * Allow storage to have sufficent space for an iterator for each
+	 * possibly nested cgroup plus an iterator for events with no cgroup.
+	 */
+	for (heap_size = 1; css; css = css->parent)
+		heap_size++;
+
+	for_each_possible_cpu(cpu) {
+		cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu);
+		if (heap_size <= cpuctx->heap_size)
+			continue;
+
+		storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
+				       GFP_KERNEL, cpu_to_node(cpu));
+		if (!storage) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		raw_spin_lock_irq(&cpuctx->ctx.lock);
+		if (cpuctx->heap_size < heap_size) {
+			swap(cpuctx->heap, storage);
+			if (storage == cpuctx->heap_default)
+				storage = NULL;
+			cpuctx->heap_size = heap_size;
+		}
+		raw_spin_unlock_irq(&cpuctx->ctx.lock);
+
+		kfree(storage);
+	}
+
+	return ret;
+}
+
+static inline int perf_cgroup_connect(int fd, struct perf_event *event,
+				      struct perf_event_attr *attr,
+				      struct perf_event *group_leader)
+{
+	struct perf_cgroup *cgrp;
+	struct cgroup_subsys_state *css;
+	struct fd f = fdget(fd);
+	int ret = 0;
+
+	if (!f.file)
+		return -EBADF;
+
+	css = css_tryget_online_from_dir(f.file->f_path.dentry,
+					 &perf_event_cgrp_subsys);
+	if (IS_ERR(css)) {
+		ret = PTR_ERR(css);
+		goto out;
+	}
+
+	ret = perf_cgroup_ensure_storage(event, css);
+	if (ret)
+		goto out;
+
+	cgrp = container_of(css, struct perf_cgroup, css);
+	event->cgrp = cgrp;
+
+	/*
+	 * all events in a group must monitor
+	 * the same cgroup because a task belongs
+	 * to only one perf cgroup at a time
+	 */
+	if (group_leader && group_leader->cgrp != cgrp) {
+		perf_detach_cgroup(event);
+		ret = -EINVAL;
+	}
+out:
+	fdput(f);
+	return ret;
+}
+
+static inline void
+perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
+{
+	struct perf_cpu_context *cpuctx;
+
+	if (!is_cgroup_event(event))
+		return;
+
+	/*
+	 * Because cgroup events are always per-cpu events,
+	 * @ctx == &cpuctx->ctx.
+	 */
+	cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
+
+	if (ctx->nr_cgroups++)
+		return;
+
+	cpuctx->cgrp = perf_cgroup_from_task(current, ctx);
+	list_add(&cpuctx->cgrp_cpuctx_entry,
+			per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
+}
+
+static inline void
+perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
+{
+	struct perf_cpu_context *cpuctx;
+
+	if (!is_cgroup_event(event))
+		return;
+
+	/*
+	 * Because cgroup events are always per-cpu events,
+	 * @ctx == &cpuctx->ctx.
+	 */
+	cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
+
+	if (--ctx->nr_cgroups)
+		return;
+
+	cpuctx->cgrp = NULL;
+	list_del(&cpuctx->cgrp_cpuctx_entry);
+}
+
+#else /* !CONFIG_CGROUP_PERF */
+
+static inline bool
+perf_cgroup_match(struct perf_event *event)
+{
+	return true;
+}
+
+static inline void perf_detach_cgroup(struct perf_event *event)
+{}
+
+static inline int is_cgroup_event(struct perf_event *event)
+{
+	return 0;
+}
+
+static inline void update_cgrp_time_from_event(struct perf_event *event)
+{
+}
+
+static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx,
+						bool final)
+{
+}
+
+static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
+				      struct perf_event_attr *attr,
+				      struct perf_event *group_leader)
+{
+	return -EINVAL;
+}
+
+static inline void
+perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
+{
+}
+
+static inline u64 perf_cgroup_event_time(struct perf_event *event)
+{
+	return 0;
+}
+
+static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
+{
+	return 0;
+}
+
+static inline void
+perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
+{
+}
+
+static inline void
+perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
+{
+}
+
+static void perf_cgroup_switch(struct task_struct *task)
+{
+}
+#endif
+
+/*
+ * set default to be dependent on timer tick just
+ * like original code
+ */
+#define PERF_CPU_HRTIMER (1000 / HZ)
+/*
+ * function must be called with interrupts disabled
+ */
+static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
+{
+	struct perf_cpu_context *cpuctx;
+	bool rotations;
+
+	lockdep_assert_irqs_disabled();
+
+	cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
+	rotations = perf_rotate_context(cpuctx);
+
+	raw_spin_lock(&cpuctx->hrtimer_lock);
+	if (rotations)
+		hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
+	else
+		cpuctx->hrtimer_active = 0;
+	raw_spin_unlock(&cpuctx->hrtimer_lock);
+
+	return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
+}
+
+static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
+{
+	struct hrtimer *timer = &cpuctx->hrtimer;
+	struct pmu *pmu = cpuctx->ctx.pmu;
+	u64 interval;
+
+	/* no multiplexing needed for SW PMU */
+	if (pmu->task_ctx_nr == perf_sw_context)
+		return;
+
+	/*
+	 * check default is sane, if not set then force to
+	 * default interval (1/tick)
+	 */
+	interval = pmu->hrtimer_interval_ms;
+	if (interval < 1)
+		interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
+
+	cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
+
+	raw_spin_lock_init(&cpuctx->hrtimer_lock);
+	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
+	timer->function = perf_mux_hrtimer_handler;
+}
+
+static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
+{
+	struct hrtimer *timer = &cpuctx->hrtimer;
+	struct pmu *pmu = cpuctx->ctx.pmu;
+	unsigned long flags;
+
+	/* not for SW PMU */
+	if (pmu->task_ctx_nr == perf_sw_context)
+		return 0;
+
+	raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
+	if (!cpuctx->hrtimer_active) {
+		cpuctx->hrtimer_active = 1;
+		hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
+		hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
+	}
+	raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
+
+	return 0;
+}
+
+static int perf_mux_hrtimer_restart_ipi(void *arg)
+{
+	return perf_mux_hrtimer_restart(arg);
+}
+
+void perf_pmu_disable(struct pmu *pmu)
+{
+	int *count = this_cpu_ptr(pmu->pmu_disable_count);
+	if (!(*count)++)
+		pmu->pmu_disable(pmu);
+}
+
+void perf_pmu_enable(struct pmu *pmu)
+{
+	int *count = this_cpu_ptr(pmu->pmu_disable_count);
+	if (!--(*count))
+		pmu->pmu_enable(pmu);
+}
+
+static DEFINE_PER_CPU(struct list_head, active_ctx_list);
+
+/*
+ * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
+ * perf_event_task_tick() are fully serialized because they're strictly cpu
+ * affine and perf_event_ctx{activate,deactivate} are called with IRQs
+ * disabled, while perf_event_task_tick is called from IRQ context.
+ */
+static void perf_event_ctx_activate(struct perf_event_context *ctx)
+{
+	struct list_head *head = this_cpu_ptr(&active_ctx_list);
+
+	lockdep_assert_irqs_disabled();
+
+	WARN_ON(!list_empty(&ctx->active_ctx_list));
+
+	list_add(&ctx->active_ctx_list, head);
+}
+
+static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
+{
+	lockdep_assert_irqs_disabled();
+
+	WARN_ON(list_empty(&ctx->active_ctx_list));
+
+	list_del_init(&ctx->active_ctx_list);
+}
+
+static void get_ctx(struct perf_event_context *ctx)
+{
+	refcount_inc(&ctx->refcount);
+}
+
+static void *alloc_task_ctx_data(struct pmu *pmu)
+{
+	if (pmu->task_ctx_cache)
+		return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL);
+
+	return NULL;
+}
+
+static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
+{
+	if (pmu->task_ctx_cache && task_ctx_data)
+		kmem_cache_free(pmu->task_ctx_cache, task_ctx_data);
+}
+
+static void free_ctx(struct rcu_head *head)
+{
+	struct perf_event_context *ctx;
+
+	ctx = container_of(head, struct perf_event_context, rcu_head);
+	free_task_ctx_data(ctx->pmu, ctx->task_ctx_data);
+	kfree(ctx);
+}
+
+static void put_ctx(struct perf_event_context *ctx)
+{
+	if (refcount_dec_and_test(&ctx->refcount)) {
+		if (ctx->parent_ctx)
+			put_ctx(ctx->parent_ctx);
+		if (ctx->task && ctx->task != TASK_TOMBSTONE)
+			put_task_struct(ctx->task);
+		call_rcu(&ctx->rcu_head, free_ctx);
+	}
+}
+
+/*
+ * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
+ * perf_pmu_migrate_context() we need some magic.
+ *
+ * Those places that change perf_event::ctx will hold both
+ * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
+ *
+ * Lock ordering is by mutex address. There are two other sites where
+ * perf_event_context::mutex nests and those are:
+ *
+ *  - perf_event_exit_task_context()	[ child , 0 ]
+ *      perf_event_exit_event()
+ *        put_event()			[ parent, 1 ]
+ *
+ *  - perf_event_init_context()		[ parent, 0 ]
+ *      inherit_task_group()
+ *        inherit_group()
+ *          inherit_event()
+ *            perf_event_alloc()
+ *              perf_init_event()
+ *                perf_try_init_event()	[ child , 1 ]
+ *
+ * While it appears there is an obvious deadlock here -- the parent and child
+ * nesting levels are inverted between the two. This is in fact safe because
+ * life-time rules separate them. That is an exiting task cannot fork, and a
+ * spawning task cannot (yet) exit.
+ *
+ * But remember that these are parent<->child context relations, and
+ * migration does not affect children, therefore these two orderings should not
+ * interact.
+ *
+ * The change in perf_event::ctx does not affect children (as claimed above)
+ * because the sys_perf_event_open() case will install a new event and break
+ * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
+ * concerned with cpuctx and that doesn't have children.
+ *
+ * The places that change perf_event::ctx will issue:
+ *
+ *   perf_remove_from_context();
+ *   synchronize_rcu();
+ *   perf_install_in_context();
+ *
+ * to affect the change. The remove_from_context() + synchronize_rcu() should
+ * quiesce the event, after which we can install it in the new location. This
+ * means that only external vectors (perf_fops, prctl) can perturb the event
+ * while in transit. Therefore all such accessors should also acquire
+ * perf_event_context::mutex to serialize against this.
+ *
+ * However; because event->ctx can change while we're waiting to acquire
+ * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
+ * function.
+ *
+ * Lock order:
+ *    exec_update_lock
+ *	task_struct::perf_event_mutex
+ *	  perf_event_context::mutex
+ *	    perf_event::child_mutex;
+ *	      perf_event_context::lock
+ *	    perf_event::mmap_mutex
+ *	    mmap_lock
+ *	      perf_addr_filters_head::lock
+ *
+ *    cpu_hotplug_lock
+ *      pmus_lock
+ *	  cpuctx->mutex / perf_event_context::mutex
+ */
+static struct perf_event_context *
+perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
+{
+	struct perf_event_context *ctx;
+
+again:
+	rcu_read_lock();
+	ctx = READ_ONCE(event->ctx);
+	if (!refcount_inc_not_zero(&ctx->refcount)) {
+		rcu_read_unlock();
+		goto again;
+	}
+	rcu_read_unlock();
+
+	mutex_lock_nested(&ctx->mutex, nesting);
+	if (event->ctx != ctx) {
+		mutex_unlock(&ctx->mutex);
+		put_ctx(ctx);
+		goto again;
+	}
+
+	return ctx;
+}
+
+static inline struct perf_event_context *
+perf_event_ctx_lock(struct perf_event *event)
+{
+	return perf_event_ctx_lock_nested(event, 0);
+}
+
+static void perf_event_ctx_unlock(struct perf_event *event,
+				  struct perf_event_context *ctx)
+{
+	mutex_unlock(&ctx->mutex);
+	put_ctx(ctx);
+}
+
+/*
+ * This must be done under the ctx->lock, such as to serialize against
+ * context_equiv(), therefore we cannot call put_ctx() since that might end up
+ * calling scheduler related locks and ctx->lock nests inside those.
+ */
+static __must_check struct perf_event_context *
+unclone_ctx(struct perf_event_context *ctx)
+{
+	struct perf_event_context *parent_ctx = ctx->parent_ctx;
+
+	lockdep_assert_held(&ctx->lock);
+
+	if (parent_ctx)
+		ctx->parent_ctx = NULL;
+	ctx->generation++;
+
+	return parent_ctx;
+}
+
+static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
+				enum pid_type type)
+{
+	u32 nr;
+	/*
+	 * only top level events have the pid namespace they were created in
+	 */
+	if (event->parent)
+		event = event->parent;
+
+	nr = __task_pid_nr_ns(p, type, event->ns);
+	/* avoid -1 if it is idle thread or runs in another ns */
+	if (!nr && !pid_alive(p))
+		nr = -1;
+	return nr;
+}
+
+static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
+{
+	return perf_event_pid_type(event, p, PIDTYPE_TGID);
+}
+
+static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
+{
+	return perf_event_pid_type(event, p, PIDTYPE_PID);
+}
+
+/*
+ * If we inherit events we want to return the parent event id
+ * to userspace.
+ */
+static u64 primary_event_id(struct perf_event *event)
+{
+	u64 id = event->id;
+
+	if (event->parent)
+		id = event->parent->id;
+
+	return id;
+}
+
+/*
+ * Get the perf_event_context for a task and lock it.
+ *
+ * This has to cope with the fact that until it is locked,
+ * the context could get moved to another task.
+ */
+static struct perf_event_context *
+perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
+{
+	struct perf_event_context *ctx;
+
+retry:
+	/*
+	 * One of the few rules of preemptible RCU is that one cannot do
+	 * rcu_read_unlock() while holding a scheduler (or nested) lock when
+	 * part of the read side critical section was irqs-enabled -- see
+	 * rcu_read_unlock_special().
+	 *
+	 * Since ctx->lock nests under rq->lock we must ensure the entire read
+	 * side critical section has interrupts disabled.
+	 */
+	local_irq_save(*flags);
+	rcu_read_lock();
+	ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
+	if (ctx) {
+		/*
+		 * If this context is a clone of another, it might
+		 * get swapped for another underneath us by
+		 * perf_event_task_sched_out, though the
+		 * rcu_read_lock() protects us from any context
+		 * getting freed.  Lock the context and check if it
+		 * got swapped before we could get the lock, and retry
+		 * if so.  If we locked the right context, then it
+		 * can't get swapped on us any more.
+		 */
+		raw_spin_lock(&ctx->lock);
+		if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
+			raw_spin_unlock(&ctx->lock);
+			rcu_read_unlock();
+			local_irq_restore(*flags);
+			goto retry;
+		}
+
+		if (ctx->task == TASK_TOMBSTONE ||
+		    !refcount_inc_not_zero(&ctx->refcount)) {
+			raw_spin_unlock(&ctx->lock);
+			ctx = NULL;
+		} else {
+			WARN_ON_ONCE(ctx->task != task);
+		}
+	}
+	rcu_read_unlock();
+	if (!ctx)
+		local_irq_restore(*flags);
+	return ctx;
+}
+
+/*
+ * Get the context for a task and increment its pin_count so it
+ * can't get swapped to another task.  This also increments its
+ * reference count so that the context can't get freed.
+ */
+static struct perf_event_context *
+perf_pin_task_context(struct task_struct *task, int ctxn)
+{
+	struct perf_event_context *ctx;
+	unsigned long flags;
+
+	ctx = perf_lock_task_context(task, ctxn, &flags);
+	if (ctx) {
+		++ctx->pin_count;
+		raw_spin_unlock_irqrestore(&ctx->lock, flags);
+	}
+	return ctx;
+}
+
+static void perf_unpin_context(struct perf_event_context *ctx)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&ctx->lock, flags);
+	--ctx->pin_count;
+	raw_spin_unlock_irqrestore(&ctx->lock, flags);
+}
+
+/*
+ * Update the record of the current time in a context.
+ */
+static void __update_context_time(struct perf_event_context *ctx, bool adv)
+{
+	u64 now = perf_clock();
+
+	lockdep_assert_held(&ctx->lock);
+
+	if (adv)
+		ctx->time += now - ctx->timestamp;
+	ctx->timestamp = now;
+
+	/*
+	 * The above: time' = time + (now - timestamp), can be re-arranged
+	 * into: time` = now + (time - timestamp), which gives a single value
+	 * offset to compute future time without locks on.
+	 *
+	 * See perf_event_time_now(), which can be used from NMI context where
+	 * it's (obviously) not possible to acquire ctx->lock in order to read
+	 * both the above values in a consistent manner.
+	 */
+	WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp);
+}
+
+static void update_context_time(struct perf_event_context *ctx)
+{
+	__update_context_time(ctx, true);
+}
+
+static u64 perf_event_time(struct perf_event *event)
+{
+	struct perf_event_context *ctx = event->ctx;
+
+	if (unlikely(!ctx))
+		return 0;
+
+	if (is_cgroup_event(event))
+		return perf_cgroup_event_time(event);
+
+	return ctx->time;
+}
+
+static u64 perf_event_time_now(struct perf_event *event, u64 now)
+{
+	struct perf_event_context *ctx = event->ctx;
+
+	if (unlikely(!ctx))
+		return 0;
+
+	if (is_cgroup_event(event))
+		return perf_cgroup_event_time_now(event, now);
+
+	if (!(__load_acquire(&ctx->is_active) & EVENT_TIME))
+		return ctx->time;
+
+	now += READ_ONCE(ctx->timeoffset);
+	return now;
+}
+
+static enum event_type_t get_event_type(struct perf_event *event)
+{
+	struct perf_event_context *ctx = event->ctx;
+	enum event_type_t event_type;
+
+	lockdep_assert_held(&ctx->lock);
+
+	/*
+	 * It's 'group type', really, because if our group leader is
+	 * pinned, so are we.
+	 */
+	if (event->group_leader != event)
+		event = event->group_leader;
+
+	event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
+	if (!ctx->task)
+		event_type |= EVENT_CPU;
+
+	return event_type;
+}
+
+/*
+ * Helper function to initialize event group nodes.
+ */
+static void init_event_group(struct perf_event *event)
+{
+	RB_CLEAR_NODE(&event->group_node);
+	event->group_index = 0;
+}
+
+/*
+ * Extract pinned or flexible groups from the context
+ * based on event attrs bits.
+ */
+static struct perf_event_groups *
+get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
+{
+	if (event->attr.pinned)
+		return &ctx->pinned_groups;
+	else
+		return &ctx->flexible_groups;
+}
+
+/*
+ * Helper function to initializes perf_event_group trees.
+ */
+static void perf_event_groups_init(struct perf_event_groups *groups)
+{
+	groups->tree = RB_ROOT;
+	groups->index = 0;
+}
+
+static inline struct cgroup *event_cgroup(const struct perf_event *event)
+{
+	struct cgroup *cgroup = NULL;
+
+#ifdef CONFIG_CGROUP_PERF
+	if (event->cgrp)
+		cgroup = event->cgrp->css.cgroup;
+#endif
+
+	return cgroup;
+}
+
+/*
+ * Compare function for event groups;
+ *
+ * Implements complex key that first sorts by CPU and then by virtual index
+ * which provides ordering when rotating groups for the same CPU.
+ */
+static __always_inline int
+perf_event_groups_cmp(const int left_cpu, const struct cgroup *left_cgroup,
+		      const u64 left_group_index, const struct perf_event *right)
+{
+	if (left_cpu < right->cpu)
+		return -1;
+	if (left_cpu > right->cpu)
+		return 1;
+
+#ifdef CONFIG_CGROUP_PERF
+	{
+		const struct cgroup *right_cgroup = event_cgroup(right);
+
+		if (left_cgroup != right_cgroup) {
+			if (!left_cgroup) {
+				/*
+				 * Left has no cgroup but right does, no
+				 * cgroups come first.
+				 */
+				return -1;
+			}
+			if (!right_cgroup) {
+				/*
+				 * Right has no cgroup but left does, no
+				 * cgroups come first.
+				 */
+				return 1;
+			}
+			/* Two dissimilar cgroups, order by id. */
+			if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
+				return -1;
+
+			return 1;
+		}
+	}
+#endif
+
+	if (left_group_index < right->group_index)
+		return -1;
+	if (left_group_index > right->group_index)
+		return 1;
+
+	return 0;
+}
+
+#define __node_2_pe(node) \
+	rb_entry((node), struct perf_event, group_node)
+
+static inline bool __group_less(struct rb_node *a, const struct rb_node *b)
+{
+	struct perf_event *e = __node_2_pe(a);
+	return perf_event_groups_cmp(e->cpu, event_cgroup(e), e->group_index,
+				     __node_2_pe(b)) < 0;
+}
+
+struct __group_key {
+	int cpu;
+	struct cgroup *cgroup;
+};
+
+static inline int __group_cmp(const void *key, const struct rb_node *node)
+{
+	const struct __group_key *a = key;
+	const struct perf_event *b = __node_2_pe(node);
+
+	/* partial/subtree match: @cpu, @cgroup; ignore: @group_index */
+	return perf_event_groups_cmp(a->cpu, a->cgroup, b->group_index, b);
+}
+
+/*
+ * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
+ * key (see perf_event_groups_less). This places it last inside the CPU
+ * subtree.
+ */
+static void
+perf_event_groups_insert(struct perf_event_groups *groups,
+			 struct perf_event *event)
+{
+	event->group_index = ++groups->index;
+
+	rb_add(&event->group_node, &groups->tree, __group_less);
+}
+
+/*
+ * Helper function to insert event into the pinned or flexible groups.
+ */
+static void
+add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
+{
+	struct perf_event_groups *groups;
+
+	groups = get_event_groups(event, ctx);
+	perf_event_groups_insert(groups, event);
+}
+
+/*
+ * Delete a group from a tree.
+ */
+static void
+perf_event_groups_delete(struct perf_event_groups *groups,
+			 struct perf_event *event)
+{
+	WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
+		     RB_EMPTY_ROOT(&groups->tree));
+
+	rb_erase(&event->group_node, &groups->tree);
+	init_event_group(event);
+}
+
+/*
+ * Helper function to delete event from its groups.
+ */
+static void
+del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
+{
+	struct perf_event_groups *groups;
+
+	groups = get_event_groups(event, ctx);
+	perf_event_groups_delete(groups, event);
+}
+
+/*
+ * Get the leftmost event in the cpu/cgroup subtree.
+ */
+static struct perf_event *
+perf_event_groups_first(struct perf_event_groups *groups, int cpu,
+			struct cgroup *cgrp)
+{
+	struct __group_key key = {
+		.cpu = cpu,
+		.cgroup = cgrp,
+	};
+	struct rb_node *node;
+
+	node = rb_find_first(&key, &groups->tree, __group_cmp);
+	if (node)
+		return __node_2_pe(node);
+
+	return NULL;
+}
+
+/*
+ * Like rb_entry_next_safe() for the @cpu subtree.
+ */
+static struct perf_event *
+perf_event_groups_next(struct perf_event *event)
+{
+	struct __group_key key = {
+		.cpu = event->cpu,
+		.cgroup = event_cgroup(event),
+	};
+	struct rb_node *next;
+
+	next = rb_next_match(&key, &event->group_node, __group_cmp);
+	if (next)
+		return __node_2_pe(next);
+
+	return NULL;
+}
+
+/*
+ * Iterate through the whole groups tree.
+ */
+#define perf_event_groups_for_each(event, groups)			\
+	for (event = rb_entry_safe(rb_first(&((groups)->tree)),		\
+				typeof(*event), group_node); event;	\
+		event = rb_entry_safe(rb_next(&event->group_node),	\
+				typeof(*event), group_node))
+
+/*
+ * Add an event from the lists for its context.
+ * Must be called with ctx->mutex and ctx->lock held.
+ */
+static void
+list_add_event(struct perf_event *event, struct perf_event_context *ctx)
+{
+	lockdep_assert_held(&ctx->lock);
+
+	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
+	event->attach_state |= PERF_ATTACH_CONTEXT;
+
+	event->tstamp = perf_event_time(event);
+
+	/*
+	 * If we're a stand alone event or group leader, we go to the context
+	 * list, group events are kept attached to the group so that
+	 * perf_group_detach can, at all times, locate all siblings.
+	 */
+	if (event->group_leader == event) {
+		event->group_caps = event->event_caps;
+		add_event_to_groups(event, ctx);
+	}
+
+	list_add_rcu(&event->event_entry, &ctx->event_list);
+	ctx->nr_events++;
+	if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
+		ctx->nr_user++;
+	if (event->attr.inherit_stat)
+		ctx->nr_stat++;
+
+	if (event->state > PERF_EVENT_STATE_OFF)
+		perf_cgroup_event_enable(event, ctx);
+
+	ctx->generation++;
+}
+
+/*
+ * Initialize event state based on the perf_event_attr::disabled.
+ */
+static inline void perf_event__state_init(struct perf_event *event)
+{
+	event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
+					      PERF_EVENT_STATE_INACTIVE;
+}
+
+static int __perf_event_read_size(u64 read_format, int nr_siblings)
+{
+	int entry = sizeof(u64); /* value */
+	int size = 0;
+	int nr = 1;
+
+	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+		size += sizeof(u64);
+
+	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+		size += sizeof(u64);
+
+	if (read_format & PERF_FORMAT_ID)
+		entry += sizeof(u64);
+
+	if (read_format & PERF_FORMAT_LOST)
+		entry += sizeof(u64);
+
+	if (read_format & PERF_FORMAT_GROUP) {
+		nr += nr_siblings;
+		size += sizeof(u64);
+	}
+
+	/*
+	 * Since perf_event_validate_size() limits this to 16k and inhibits
+	 * adding more siblings, this will never overflow.
+	 */
+	return size + nr * entry;
+}
+
+static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
+{
+	struct perf_sample_data *data;
+	u16 size = 0;
+
+	if (sample_type & PERF_SAMPLE_IP)
+		size += sizeof(data->ip);
+
+	if (sample_type & PERF_SAMPLE_ADDR)
+		size += sizeof(data->addr);
+
+	if (sample_type & PERF_SAMPLE_PERIOD)
+		size += sizeof(data->period);
+
+	if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
+		size += sizeof(data->weight.full);
+
+	if (sample_type & PERF_SAMPLE_READ)
+		size += event->read_size;
+
+	if (sample_type & PERF_SAMPLE_DATA_SRC)
+		size += sizeof(data->data_src.val);
+
+	if (sample_type & PERF_SAMPLE_TRANSACTION)
+		size += sizeof(data->txn);
+
+	if (sample_type & PERF_SAMPLE_PHYS_ADDR)
+		size += sizeof(data->phys_addr);
+
+	if (sample_type & PERF_SAMPLE_CGROUP)
+		size += sizeof(data->cgroup);
+
+	if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
+		size += sizeof(data->data_page_size);
+
+	if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
+		size += sizeof(data->code_page_size);
+
+	event->header_size = size;
+}
+
+/*
+ * Called at perf_event creation and when events are attached/detached from a
+ * group.
+ */
+static void perf_event__header_size(struct perf_event *event)
+{
+	event->read_size =
+		__perf_event_read_size(event->attr.read_format,
+				       event->group_leader->nr_siblings);
+	__perf_event_header_size(event, event->attr.sample_type);
+}
+
+static void perf_event__id_header_size(struct perf_event *event)
+{
+	struct perf_sample_data *data;
+	u64 sample_type = event->attr.sample_type;
+	u16 size = 0;
+
+	if (sample_type & PERF_SAMPLE_TID)
+		size += sizeof(data->tid_entry);
+
+	if (sample_type & PERF_SAMPLE_TIME)
+		size += sizeof(data->time);
+
+	if (sample_type & PERF_SAMPLE_IDENTIFIER)
+		size += sizeof(data->id);
+
+	if (sample_type & PERF_SAMPLE_ID)
+		size += sizeof(data->id);
+
+	if (sample_type & PERF_SAMPLE_STREAM_ID)
+		size += sizeof(data->stream_id);
+
+	if (sample_type & PERF_SAMPLE_CPU)
+		size += sizeof(data->cpu_entry);
+
+	event->id_header_size = size;
+}
+
+/*
+ * Check that adding an event to the group does not result in anybody
+ * overflowing the 64k event limit imposed by the output buffer.
+ *
+ * Specifically, check that the read_size for the event does not exceed 16k,
+ * read_size being the one term that grows with groups size. Since read_size
+ * depends on per-event read_format, also (re)check the existing events.
+ *
+ * This leaves 48k for the constant size fields and things like callchains,
+ * branch stacks and register sets.
+ */
+static bool perf_event_validate_size(struct perf_event *event)
+{
+	struct perf_event *sibling, *group_leader = event->group_leader;
+
+	if (__perf_event_read_size(event->attr.read_format,
+				   group_leader->nr_siblings + 1) > 16*1024)
+		return false;
+
+	if (__perf_event_read_size(group_leader->attr.read_format,
+				   group_leader->nr_siblings + 1) > 16*1024)
+		return false;
+
+	/*
+	 * When creating a new group leader, group_leader->ctx is initialized
+	 * after the size has been validated, but we cannot safely use
+	 * for_each_sibling_event() until group_leader->ctx is set. A new group
+	 * leader cannot have any siblings yet, so we can safely skip checking
+	 * the non-existent siblings.
+	 */
+	if (event == group_leader)
+		return true;
+
+	for_each_sibling_event(sibling, group_leader) {
+		if (__perf_event_read_size(sibling->attr.read_format,
+					   group_leader->nr_siblings + 1) > 16*1024)
+			return false;
+	}
+
+	return true;
+}
+
+static void perf_group_attach(struct perf_event *event)
+{
+	struct perf_event *group_leader = event->group_leader, *pos;
+
+	lockdep_assert_held(&event->ctx->lock);
+
+	/*
+	 * We can have double attach due to group movement in perf_event_open.
+	 */
+	if (event->attach_state & PERF_ATTACH_GROUP)
+		return;
+
+	event->attach_state |= PERF_ATTACH_GROUP;
+
+	if (group_leader == event)
+		return;
+
+	WARN_ON_ONCE(group_leader->ctx != event->ctx);
+
+	group_leader->group_caps &= event->event_caps;
+
+	list_add_tail(&event->sibling_list, &group_leader->sibling_list);
+	group_leader->nr_siblings++;
+	group_leader->group_generation++;
+
+	perf_event__header_size(group_leader);
+
+	for_each_sibling_event(pos, group_leader)
+		perf_event__header_size(pos);
+}
+
+/*
+ * Remove an event from the lists for its context.
+ * Must be called with ctx->mutex and ctx->lock held.
+ */
+static void
+list_del_event(struct perf_event *event, struct perf_event_context *ctx)
+{
+	WARN_ON_ONCE(event->ctx != ctx);
+	lockdep_assert_held(&ctx->lock);
+
+	/*
+	 * We can have double detach due to exit/hot-unplug + close.
+	 */
+	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
+		return;
+
+	event->attach_state &= ~PERF_ATTACH_CONTEXT;
+
+	ctx->nr_events--;
+	if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
+		ctx->nr_user--;
+	if (event->attr.inherit_stat)
+		ctx->nr_stat--;
+
+	list_del_rcu(&event->event_entry);
+
+	if (event->group_leader == event)
+		del_event_from_groups(event, ctx);
+
+	/*
+	 * If event was in error state, then keep it
+	 * that way, otherwise bogus counts will be
+	 * returned on read(). The only way to get out
+	 * of error state is by explicit re-enabling
+	 * of the event
+	 */
+	if (event->state > PERF_EVENT_STATE_OFF) {
+		perf_cgroup_event_disable(event, ctx);
+		perf_event_set_state(event, PERF_EVENT_STATE_OFF);
+	}
+
+	ctx->generation++;
+}
+
+static int
+perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
+{
+	if (!has_aux(aux_event))
+		return 0;
+
+	if (!event->pmu->aux_output_match)
+		return 0;
+
+	return event->pmu->aux_output_match(aux_event);
+}
+
+static void put_event(struct perf_event *event);
+static void event_sched_out(struct perf_event *event,
+			    struct perf_cpu_context *cpuctx,
+			    struct perf_event_context *ctx);
+
+static void perf_put_aux_event(struct perf_event *event)
+{
+	struct perf_event_context *ctx = event->ctx;
+	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+	struct perf_event *iter;
+
+	/*
+	 * If event uses aux_event tear down the link
+	 */
+	if (event->aux_event) {
+		iter = event->aux_event;
+		event->aux_event = NULL;
+		put_event(iter);
+		return;
+	}
+
+	/*
+	 * If the event is an aux_event, tear down all links to
+	 * it from other events.
+	 */
+	for_each_sibling_event(iter, event->group_leader) {
+		if (iter->aux_event != event)
+			continue;
+
+		iter->aux_event = NULL;
+		put_event(event);
+
+		/*
+		 * If it's ACTIVE, schedule it out and put it into ERROR
+		 * state so that we don't try to schedule it again. Note
+		 * that perf_event_enable() will clear the ERROR status.
+		 */
+		event_sched_out(iter, cpuctx, ctx);
+		perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
+	}
+}
+
+static bool perf_need_aux_event(struct perf_event *event)
+{
+	return !!event->attr.aux_output || !!event->attr.aux_sample_size;
+}
+
+static int perf_get_aux_event(struct perf_event *event,
+			      struct perf_event *group_leader)
+{
+	/*
+	 * Our group leader must be an aux event if we want to be
+	 * an aux_output. This way, the aux event will precede its
+	 * aux_output events in the group, and therefore will always
+	 * schedule first.
+	 */
+	if (!group_leader)
+		return 0;
+
+	/*
+	 * aux_output and aux_sample_size are mutually exclusive.
+	 */
+	if (event->attr.aux_output && event->attr.aux_sample_size)
+		return 0;
+
+	if (event->attr.aux_output &&
+	    !perf_aux_output_match(event, group_leader))
+		return 0;
+
+	if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
+		return 0;
+
+	if (!atomic_long_inc_not_zero(&group_leader->refcount))
+		return 0;
+
+	/*
+	 * Link aux_outputs to their aux event; this is undone in
+	 * perf_group_detach() by perf_put_aux_event(). When the
+	 * group in torn down, the aux_output events loose their
+	 * link to the aux_event and can't schedule any more.
+	 */
+	event->aux_event = group_leader;
+
+	return 1;
+}
+
+static inline struct list_head *get_event_list(struct perf_event *event)
+{
+	struct perf_event_context *ctx = event->ctx;
+	return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
+}
+
+/*
+ * Events that have PERF_EV_CAP_SIBLING require being part of a group and
+ * cannot exist on their own, schedule them out and move them into the ERROR
+ * state. Also see _perf_event_enable(), it will not be able to recover
+ * this ERROR state.
+ */
+static inline void perf_remove_sibling_event(struct perf_event *event)
+{
+	struct perf_event_context *ctx = event->ctx;
+	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+
+	event_sched_out(event, cpuctx, ctx);
+	perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
+}
+
+static void perf_group_detach(struct perf_event *event)
+{
+	struct perf_event *leader = event->group_leader;
+	struct perf_event *sibling, *tmp;
+	struct perf_event_context *ctx = event->ctx;
+
+	lockdep_assert_held(&ctx->lock);
+
+	/*
+	 * We can have double detach due to exit/hot-unplug + close.
+	 */
+	if (!(event->attach_state & PERF_ATTACH_GROUP))
+		return;
+
+	event->attach_state &= ~PERF_ATTACH_GROUP;
+
+	perf_put_aux_event(event);
+
+	/*
+	 * If this is a sibling, remove it from its group.
+	 */
+	if (leader != event) {
+		list_del_init(&event->sibling_list);
+		event->group_leader->nr_siblings--;
+		event->group_leader->group_generation++;
+		goto out;
+	}
+
+	/*
+	 * If this was a group event with sibling events then
+	 * upgrade the siblings to singleton events by adding them
+	 * to whatever list we are on.
+	 */
+	list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
+
+		if (sibling->event_caps & PERF_EV_CAP_SIBLING)
+			perf_remove_sibling_event(sibling);
+
+		sibling->group_leader = sibling;
+		list_del_init(&sibling->sibling_list);
+
+		/* Inherit group flags from the previous leader */
+		sibling->group_caps = event->group_caps;
+
+		if (sibling->attach_state & PERF_ATTACH_CONTEXT) {
+			add_event_to_groups(sibling, event->ctx);
+
+			if (sibling->state == PERF_EVENT_STATE_ACTIVE)
+				list_add_tail(&sibling->active_list, get_event_list(sibling));
+		}
+
+		WARN_ON_ONCE(sibling->ctx != event->ctx);
+	}
+
+out:
+	for_each_sibling_event(tmp, leader)
+		perf_event__header_size(tmp);
+
+	perf_event__header_size(leader);
+}
+
+static void sync_child_event(struct perf_event *child_event);
+
+static void perf_child_detach(struct perf_event *event)
+{
+	struct perf_event *parent_event = event->parent;
+
+	if (!(event->attach_state & PERF_ATTACH_CHILD))
+		return;
+
+	event->attach_state &= ~PERF_ATTACH_CHILD;
+
+	if (WARN_ON_ONCE(!parent_event))
+		return;
+
+	lockdep_assert_held(&parent_event->child_mutex);
+
+	sync_child_event(event);
+	list_del_init(&event->child_list);
+}
+
+static bool is_orphaned_event(struct perf_event *event)
+{
+	return event->state == PERF_EVENT_STATE_DEAD;
+}
+
+static inline int __pmu_filter_match(struct perf_event *event)
+{
+	struct pmu *pmu = event->pmu;
+	return pmu->filter_match ? pmu->filter_match(event) : 1;
+}
+
+/*
+ * Check whether we should attempt to schedule an event group based on
+ * PMU-specific filtering. An event group can consist of HW and SW events,
+ * potentially with a SW leader, so we must check all the filters, to
+ * determine whether a group is schedulable:
+ */
+static inline int pmu_filter_match(struct perf_event *event)
+{
+	struct perf_event *sibling;
+	unsigned long flags;
+	int ret = 1;
+
+	if (!__pmu_filter_match(event))
+		return 0;
+
+	local_irq_save(flags);
+	for_each_sibling_event(sibling, event) {
+		if (!__pmu_filter_match(sibling)) {
+			ret = 0;
+			break;
+		}
+	}
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static inline int
+event_filter_match(struct perf_event *event)
+{
+	return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
+	       perf_cgroup_match(event) && pmu_filter_match(event);
+}
+
+static void
+event_sched_out(struct perf_event *event,
+		  struct perf_cpu_context *cpuctx,
+		  struct perf_event_context *ctx)
+{
+	enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
+
+	WARN_ON_ONCE(event->ctx != ctx);
+	lockdep_assert_held(&ctx->lock);
+
+	if (event->state != PERF_EVENT_STATE_ACTIVE)
+		return;
+
+	/*
+	 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
+	 * we can schedule events _OUT_ individually through things like
+	 * __perf_remove_from_context().
+	 */
+	list_del_init(&event->active_list);
+
+	perf_pmu_disable(event->pmu);
+
+	event->pmu->del(event, 0);
+	event->oncpu = -1;
+
+	if (event->pending_disable) {
+		event->pending_disable = 0;
+		perf_cgroup_event_disable(event, ctx);
+		state = PERF_EVENT_STATE_OFF;
+	}
+
+	if (event->pending_sigtrap) {
+		bool dec = true;
+
+		event->pending_sigtrap = 0;
+		if (state != PERF_EVENT_STATE_OFF &&
+		    !event->pending_work) {
+			event->pending_work = 1;
+			dec = false;
+			WARN_ON_ONCE(!atomic_long_inc_not_zero(&event->refcount));
+			task_work_add(current, &event->pending_task, TWA_RESUME);
+		}
+		if (dec)
+			local_dec(&event->ctx->nr_pending);
+	}
+
+	perf_event_set_state(event, state);
+
+	if (!is_software_event(event))
+		cpuctx->active_oncpu--;
+	if (!--ctx->nr_active)
+		perf_event_ctx_deactivate(ctx);
+	if (event->attr.freq && event->attr.sample_freq)
+		ctx->nr_freq--;
+	if (event->attr.exclusive || !cpuctx->active_oncpu)
+		cpuctx->exclusive = 0;
+
+	perf_pmu_enable(event->pmu);
+}
+
+static void
+group_sched_out(struct perf_event *group_event,
+		struct perf_cpu_context *cpuctx,
+		struct perf_event_context *ctx)
+{
+	struct perf_event *event;
+
+	if (group_event->state != PERF_EVENT_STATE_ACTIVE)
+		return;
+
+	perf_pmu_disable(ctx->pmu);
+
+	event_sched_out(group_event, cpuctx, ctx);
+
+	/*
+	 * Schedule out siblings (if any):
+	 */
+	for_each_sibling_event(event, group_event)
+		event_sched_out(event, cpuctx, ctx);
+
+	perf_pmu_enable(ctx->pmu);
+}
+
+#define DETACH_GROUP	0x01UL
+#define DETACH_CHILD	0x02UL
+#define DETACH_DEAD	0x04UL
+
+/*
+ * Cross CPU call to remove a performance event
+ *
+ * We disable the event on the hardware level first. After that we
+ * remove it from the context list.
+ */
+static void
+__perf_remove_from_context(struct perf_event *event,
+			   struct perf_cpu_context *cpuctx,
+			   struct perf_event_context *ctx,
+			   void *info)
+{
+	unsigned long flags = (unsigned long)info;
+
+	if (ctx->is_active & EVENT_TIME) {
+		update_context_time(ctx);
+		update_cgrp_time_from_cpuctx(cpuctx, false);
+	}
+
+	/*
+	 * Ensure event_sched_out() switches to OFF, at the very least
+	 * this avoids raising perf_pending_task() at this time.
+	 */
+	if (flags & DETACH_DEAD)
+		event->pending_disable = 1;
+	event_sched_out(event, cpuctx, ctx);
+	if (flags & DETACH_GROUP)
+		perf_group_detach(event);
+	if (flags & DETACH_CHILD)
+		perf_child_detach(event);
+	list_del_event(event, ctx);
+	if (flags & DETACH_DEAD)
+		event->state = PERF_EVENT_STATE_DEAD;
+
+	if (!ctx->nr_events && ctx->is_active) {
+		if (ctx == &cpuctx->ctx)
+			update_cgrp_time_from_cpuctx(cpuctx, true);
+
+		ctx->is_active = 0;
+		ctx->rotate_necessary = 0;
+		if (ctx->task) {
+			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
+			cpuctx->task_ctx = NULL;
+		}
+	}
+}
+
+/*
+ * Remove the event from a task's (or a CPU's) list of events.
+ *
+ * If event->ctx is a cloned context, callers must make sure that
+ * every task struct that event->ctx->task could possibly point to
+ * remains valid.  This is OK when called from perf_release since
+ * that only calls us on the top-level context, which can't be a clone.
+ * When called from perf_event_exit_task, it's OK because the
+ * context has been detached from its task.
+ */
+static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
+{
+	struct perf_event_context *ctx = event->ctx;
+
+	lockdep_assert_held(&ctx->mutex);
+
+	/*
+	 * Because of perf_event_exit_task(), perf_remove_from_context() ought
+	 * to work in the face of TASK_TOMBSTONE, unlike every other
+	 * event_function_call() user.
+	 */
+	raw_spin_lock_irq(&ctx->lock);
+	/*
+	 * Cgroup events are per-cpu events, and must IPI because of
+	 * cgrp_cpuctx_list.
+	 */
+	if (!ctx->is_active && !is_cgroup_event(event)) {
+		__perf_remove_from_context(event, __get_cpu_context(ctx),
+					   ctx, (void *)flags);
+		raw_spin_unlock_irq(&ctx->lock);
+		return;
+	}
+	raw_spin_unlock_irq(&ctx->lock);
+
+	event_function_call(event, __perf_remove_from_context, (void *)flags);
+}
+
+/*
+ * Cross CPU call to disable a performance event
+ */
+static void __perf_event_disable(struct perf_event *event,
+				 struct perf_cpu_context *cpuctx,
+				 struct perf_event_context *ctx,
+				 void *info)
+{
+	if (event->state < PERF_EVENT_STATE_INACTIVE)
+		return;
+
+	if (ctx->is_active & EVENT_TIME) {
+		update_context_time(ctx);
+		update_cgrp_time_from_event(event);
+	}
+
+	if (event == event->group_leader)
+		group_sched_out(event, cpuctx, ctx);
+	else
+		event_sched_out(event, cpuctx, ctx);
+
+	perf_event_set_state(event, PERF_EVENT_STATE_OFF);
+	perf_cgroup_event_disable(event, ctx);
+}
+
+/*
+ * Disable an event.
+ *
+ * If event->ctx is a cloned context, callers must make sure that
+ * every task struct that event->ctx->task could possibly point to
+ * remains valid.  This condition is satisfied when called through
+ * perf_event_for_each_child or perf_event_for_each because they
+ * hold the top-level event's child_mutex, so any descendant that
+ * goes to exit will block in perf_event_exit_event().
+ *
+ * When called from perf_pending_irq it's OK because event->ctx
+ * is the current context on this CPU and preemption is disabled,
+ * hence we can't get into perf_event_task_sched_out for this context.
+ */
+static void _perf_event_disable(struct perf_event *event)
+{
+	struct perf_event_context *ctx = event->ctx;
+
+	raw_spin_lock_irq(&ctx->lock);
+	if (event->state <= PERF_EVENT_STATE_OFF) {
+		raw_spin_unlock_irq(&ctx->lock);
+		return;
+	}
+	raw_spin_unlock_irq(&ctx->lock);
+
+	event_function_call(event, __perf_event_disable, NULL);
+}
+
+void perf_event_disable_local(struct perf_event *event)
+{
+	event_function_local(event, __perf_event_disable, NULL);
+}
+
+/*
+ * Strictly speaking kernel users cannot create groups and therefore this
+ * interface does not need the perf_event_ctx_lock() magic.
+ */
+void perf_event_disable(struct perf_event *event)
+{
+	struct perf_event_context *ctx;
+
+	ctx = perf_event_ctx_lock(event);
+	_perf_event_disable(event);
+	perf_event_ctx_unlock(event, ctx);
+}
+EXPORT_SYMBOL_GPL(perf_event_disable);
+
+void perf_event_disable_inatomic(struct perf_event *event)
+{
+	event->pending_disable = 1;
+	irq_work_queue(&event->pending_irq);
+}
+
+#define MAX_INTERRUPTS (~0ULL)
+
+static void perf_log_throttle(struct perf_event *event, int enable);
+static void perf_log_itrace_start(struct perf_event *event);
+
+static int
+event_sched_in(struct perf_event *event,
+		 struct perf_cpu_context *cpuctx,
+		 struct perf_event_context *ctx)
+{
+	int ret = 0;
+
+	WARN_ON_ONCE(event->ctx != ctx);
+
+	lockdep_assert_held(&ctx->lock);
+
+	if (event->state <= PERF_EVENT_STATE_OFF)
+		return 0;
+
+	WRITE_ONCE(event->oncpu, smp_processor_id());
+	/*
+	 * Order event::oncpu write to happen before the ACTIVE state is
+	 * visible. This allows perf_event_{stop,read}() to observe the correct
+	 * ->oncpu if it sees ACTIVE.
+	 */
+	smp_wmb();
+	perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
+
+	/*
+	 * Unthrottle events, since we scheduled we might have missed several
+	 * ticks already, also for a heavily scheduling task there is little
+	 * guarantee it'll get a tick in a timely manner.
+	 */
+	if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
+		perf_log_throttle(event, 1);
+		event->hw.interrupts = 0;
+	}
+
+	perf_pmu_disable(event->pmu);
+
+	perf_log_itrace_start(event);
+
+	if (event->pmu->add(event, PERF_EF_START)) {
+		perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
+		event->oncpu = -1;
+		ret = -EAGAIN;
+		goto out;
+	}
+
+	if (!is_software_event(event))
+		cpuctx->active_oncpu++;
+	if (!ctx->nr_active++)
+		perf_event_ctx_activate(ctx);
+	if (event->attr.freq && event->attr.sample_freq)
+		ctx->nr_freq++;
+
+	if (event->attr.exclusive)
+		cpuctx->exclusive = 1;
+
+out:
+	perf_pmu_enable(event->pmu);
+
+	return ret;
+}
+
+static int
+group_sched_in(struct perf_event *group_event,
+	       struct perf_cpu_context *cpuctx,
+	       struct perf_event_context *ctx)
+{
+	struct perf_event *event, *partial_group = NULL;
+	struct pmu *pmu = ctx->pmu;
+
+	if (group_event->state == PERF_EVENT_STATE_OFF)
+		return 0;
+
+	pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
+
+	if (event_sched_in(group_event, cpuctx, ctx))
+		goto error;
+
+	/*
+	 * Schedule in siblings as one group (if any):
+	 */
+	for_each_sibling_event(event, group_event) {
+		if (event_sched_in(event, cpuctx, ctx)) {
+			partial_group = event;
+			goto group_error;
+		}
+	}
+
+	if (!pmu->commit_txn(pmu))
+		return 0;
+
+group_error:
+	/*
+	 * Groups can be scheduled in as one unit only, so undo any
+	 * partial group before returning:
+	 * The events up to the failed event are scheduled out normally.
+	 */
+	for_each_sibling_event(event, group_event) {
+		if (event == partial_group)
+			break;
+
+		event_sched_out(event, cpuctx, ctx);
+	}
+	event_sched_out(group_event, cpuctx, ctx);
+
+error:
+	pmu->cancel_txn(pmu);
+	return -EAGAIN;
+}
+
+/*
+ * Work out whether we can put this event group on the CPU now.
+ */
+static int group_can_go_on(struct perf_event *event,
+			   struct perf_cpu_context *cpuctx,
+			   int can_add_hw)
+{
+	/*
+	 * Groups consisting entirely of software events can always go on.
+	 */
+	if (event->group_caps & PERF_EV_CAP_SOFTWARE)
+		return 1;
+	/*
+	 * If an exclusive group is already on, no other hardware
+	 * events can go on.
+	 */
+	if (cpuctx->exclusive)
+		return 0;
+	/*
+	 * If this group is exclusive and there are already
+	 * events on the CPU, it can't go on.
+	 */
+	if (event->attr.exclusive && !list_empty(get_event_list(event)))
+		return 0;
+	/*
+	 * Otherwise, try to add it if all previous groups were able
+	 * to go on.
+	 */
+	return can_add_hw;
+}
+
+static void add_event_to_ctx(struct perf_event *event,
+			       struct perf_event_context *ctx)
+{
+	list_add_event(event, ctx);
+	perf_group_attach(event);
+}
+
+static void ctx_sched_out(struct perf_event_context *ctx,
+			  struct perf_cpu_context *cpuctx,
+			  enum event_type_t event_type);
+static void
+ctx_sched_in(struct perf_event_context *ctx,
+	     struct perf_cpu_context *cpuctx,
+	     enum event_type_t event_type);
+
+static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
+			       struct perf_event_context *ctx,
+			       enum event_type_t event_type)
+{
+	if (!cpuctx->task_ctx)
+		return;
+
+	if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
+		return;
+
+	ctx_sched_out(ctx, cpuctx, event_type);
+}
+
+static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
+				struct perf_event_context *ctx)
+{
+	cpu_ctx_sched_in(cpuctx, EVENT_PINNED);
+	if (ctx)
+		ctx_sched_in(ctx, cpuctx, EVENT_PINNED);
+	cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
+	if (ctx)
+		ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE);
+}
+
+/*
+ * We want to maintain the following priority of scheduling:
+ *  - CPU pinned (EVENT_CPU | EVENT_PINNED)
+ *  - task pinned (EVENT_PINNED)
+ *  - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
+ *  - task flexible (EVENT_FLEXIBLE).
+ *
+ * In order to avoid unscheduling and scheduling back in everything every
+ * time an event is added, only do it for the groups of equal priority and
+ * below.
+ *
+ * This can be called after a batch operation on task events, in which case
+ * event_type is a bit mask of the types of events involved. For CPU events,
+ * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
+ */
+static void ctx_resched(struct perf_cpu_context *cpuctx,
+			struct perf_event_context *task_ctx,
+			enum event_type_t event_type)
+{
+	enum event_type_t ctx_event_type;
+	bool cpu_event = !!(event_type & EVENT_CPU);
+
+	/*
+	 * If pinned groups are involved, flexible groups also need to be
+	 * scheduled out.
+	 */
+	if (event_type & EVENT_PINNED)
+		event_type |= EVENT_FLEXIBLE;
+
+	ctx_event_type = event_type & EVENT_ALL;
+
+	perf_pmu_disable(cpuctx->ctx.pmu);
+	if (task_ctx)
+		task_ctx_sched_out(cpuctx, task_ctx, event_type);
+
+	/*
+	 * Decide which cpu ctx groups to schedule out based on the types
+	 * of events that caused rescheduling:
+	 *  - EVENT_CPU: schedule out corresponding groups;
+	 *  - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
+	 *  - otherwise, do nothing more.
+	 */
+	if (cpu_event)
+		cpu_ctx_sched_out(cpuctx, ctx_event_type);
+	else if (ctx_event_type & EVENT_PINNED)
+		cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
+
+	perf_event_sched_in(cpuctx, task_ctx);
+	perf_pmu_enable(cpuctx->ctx.pmu);
+}
+
+void perf_pmu_resched(struct pmu *pmu)
+{
+	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+	struct perf_event_context *task_ctx = cpuctx->task_ctx;
+
+	perf_ctx_lock(cpuctx, task_ctx);
+	ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
+	perf_ctx_unlock(cpuctx, task_ctx);
+}
+
+/*
+ * Cross CPU call to install and enable a performance event
+ *
+ * Very similar to remote_function() + event_function() but cannot assume that
+ * things like ctx->is_active and cpuctx->task_ctx are set.
+ */
+static int  __perf_install_in_context(void *info)
+{
+	struct perf_event *event = info;
+	struct perf_event_context *ctx = event->ctx;
+	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+	struct perf_event_context *task_ctx = cpuctx->task_ctx;
+	bool reprogram = true;
+	int ret = 0;
+
+	raw_spin_lock(&cpuctx->ctx.lock);
+	if (ctx->task) {
+		raw_spin_lock(&ctx->lock);
+		task_ctx = ctx;
+
+		reprogram = (ctx->task == current);
+
+		/*
+		 * If the task is running, it must be running on this CPU,
+		 * otherwise we cannot reprogram things.
+		 *
+		 * If its not running, we don't care, ctx->lock will
+		 * serialize against it becoming runnable.
+		 */
+		if (task_curr(ctx->task) && !reprogram) {
+			ret = -ESRCH;
+			goto unlock;
+		}
+
+		WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
+	} else if (task_ctx) {
+		raw_spin_lock(&task_ctx->lock);
+	}
+
+#ifdef CONFIG_CGROUP_PERF
+	if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
+		/*
+		 * If the current cgroup doesn't match the event's
+		 * cgroup, we should not try to schedule it.
+		 */
+		struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
+		reprogram = cgroup_is_descendant(cgrp->css.cgroup,
+					event->cgrp->css.cgroup);
+	}
+#endif
+
+	if (reprogram) {
+		ctx_sched_out(ctx, cpuctx, EVENT_TIME);
+		add_event_to_ctx(event, ctx);
+		ctx_resched(cpuctx, task_ctx, get_event_type(event));
+	} else {
+		add_event_to_ctx(event, ctx);
+	}
+
+unlock:
+	perf_ctx_unlock(cpuctx, task_ctx);
+
+	return ret;
+}
+
+static bool exclusive_event_installable(struct perf_event *event,
+					struct perf_event_context *ctx);
+
+/*
+ * Attach a performance event to a context.
+ *
+ * Very similar to event_function_call, see comment there.
+ */
+static void
+perf_install_in_context(struct perf_event_context *ctx,
+			struct perf_event *event,
+			int cpu)
+{
+	struct task_struct *task = READ_ONCE(ctx->task);
+
+	lockdep_assert_held(&ctx->mutex);
+
+	WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
+
+	if (event->cpu != -1)
+		event->cpu = cpu;
+
+	/*
+	 * Ensures that if we can observe event->ctx, both the event and ctx
+	 * will be 'complete'. See perf_iterate_sb_cpu().
+	 */
+	smp_store_release(&event->ctx, ctx);
+
+	/*
+	 * perf_event_attr::disabled events will not run and can be initialized
+	 * without IPI. Except when this is the first event for the context, in
+	 * that case we need the magic of the IPI to set ctx->is_active.
+	 * Similarly, cgroup events for the context also needs the IPI to
+	 * manipulate the cgrp_cpuctx_list.
+	 *
+	 * The IOC_ENABLE that is sure to follow the creation of a disabled
+	 * event will issue the IPI and reprogram the hardware.
+	 */
+	if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF &&
+	    ctx->nr_events && !is_cgroup_event(event)) {
+		raw_spin_lock_irq(&ctx->lock);
+		if (ctx->task == TASK_TOMBSTONE) {
+			raw_spin_unlock_irq(&ctx->lock);
+			return;
+		}
+		add_event_to_ctx(event, ctx);
+		raw_spin_unlock_irq(&ctx->lock);
+		return;
+	}
+
+	if (!task) {
+		cpu_function_call(cpu, __perf_install_in_context, event);
+		return;
+	}
+
+	/*
+	 * Should not happen, we validate the ctx is still alive before calling.
+	 */
+	if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
+		return;
+
+	/*
+	 * Installing events is tricky because we cannot rely on ctx->is_active
+	 * to be set in case this is the nr_events 0 -> 1 transition.
+	 *
+	 * Instead we use task_curr(), which tells us if the task is running.
+	 * However, since we use task_curr() outside of rq::lock, we can race
+	 * against the actual state. This means the result can be wrong.
+	 *
+	 * If we get a false positive, we retry, this is harmless.
+	 *
+	 * If we get a false negative, things are complicated. If we are after
+	 * perf_event_context_sched_in() ctx::lock will serialize us, and the
+	 * value must be correct. If we're before, it doesn't matter since
+	 * perf_event_context_sched_in() will program the counter.
+	 *
+	 * However, this hinges on the remote context switch having observed
+	 * our task->perf_event_ctxp[] store, such that it will in fact take
+	 * ctx::lock in perf_event_context_sched_in().
+	 *
+	 * We do this by task_function_call(), if the IPI fails to hit the task
+	 * we know any future context switch of task must see the
+	 * perf_event_ctpx[] store.
+	 */
+
+	/*
+	 * This smp_mb() orders the task->perf_event_ctxp[] store with the
+	 * task_cpu() load, such that if the IPI then does not find the task
+	 * running, a future context switch of that task must observe the
+	 * store.
+	 */
+	smp_mb();
+again:
+	if (!task_function_call(task, __perf_install_in_context, event))
+		return;
+
+	raw_spin_lock_irq(&ctx->lock);
+	task = ctx->task;
+	if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
+		/*
+		 * Cannot happen because we already checked above (which also
+		 * cannot happen), and we hold ctx->mutex, which serializes us
+		 * against perf_event_exit_task_context().
+		 */
+		raw_spin_unlock_irq(&ctx->lock);
+		return;
+	}
+	/*
+	 * If the task is not running, ctx->lock will avoid it becoming so,
+	 * thus we can safely install the event.
+	 */
+	if (task_curr(task)) {
+		raw_spin_unlock_irq(&ctx->lock);
+		goto again;
+	}
+	add_event_to_ctx(event, ctx);
+	raw_spin_unlock_irq(&ctx->lock);
+}
+
+/*
+ * Cross CPU call to enable a performance event
+ */
+static void __perf_event_enable(struct perf_event *event,
+				struct perf_cpu_context *cpuctx,
+				struct perf_event_context *ctx,
+				void *info)
+{
+	struct perf_event *leader = event->group_leader;
+	struct perf_event_context *task_ctx;
+
+	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
+	    event->state <= PERF_EVENT_STATE_ERROR)
+		return;
+
+	if (ctx->is_active)
+		ctx_sched_out(ctx, cpuctx, EVENT_TIME);
+
+	perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
+	perf_cgroup_event_enable(event, ctx);
+
+	if (!ctx->is_active)
+		return;
+
+	if (!event_filter_match(event)) {
+		ctx_sched_in(ctx, cpuctx, EVENT_TIME);
+		return;
+	}
+
+	/*
+	 * If the event is in a group and isn't the group leader,
+	 * then don't put it on unless the group is on.
+	 */
+	if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
+		ctx_sched_in(ctx, cpuctx, EVENT_TIME);
+		return;
+	}
+
+	task_ctx = cpuctx->task_ctx;
+	if (ctx->task)
+		WARN_ON_ONCE(task_ctx != ctx);
+
+	ctx_resched(cpuctx, task_ctx, get_event_type(event));
+}
+
+/*
+ * Enable an event.
+ *
+ * If event->ctx is a cloned context, callers must make sure that
+ * every task struct that event->ctx->task could possibly point to
+ * remains valid.  This condition is satisfied when called through
+ * perf_event_for_each_child or perf_event_for_each as described
+ * for perf_event_disable.
+ */
+static void _perf_event_enable(struct perf_event *event)
+{
+	struct perf_event_context *ctx = event->ctx;
+
+	raw_spin_lock_irq(&ctx->lock);
+	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
+	    event->state <  PERF_EVENT_STATE_ERROR) {
+out:
+		raw_spin_unlock_irq(&ctx->lock);
+		return;
+	}
+
+	/*
+	 * If the event is in error state, clear that first.
+	 *
+	 * That way, if we see the event in error state below, we know that it
+	 * has gone back into error state, as distinct from the task having
+	 * been scheduled away before the cross-call arrived.
+	 */
+	if (event->state == PERF_EVENT_STATE_ERROR) {
+		/*
+		 * Detached SIBLING events cannot leave ERROR state.
+		 */
+		if (event->event_caps & PERF_EV_CAP_SIBLING &&
+		    event->group_leader == event)
+			goto out;
+
+		event->state = PERF_EVENT_STATE_OFF;
+	}
+	raw_spin_unlock_irq(&ctx->lock);
+
+	event_function_call(event, __perf_event_enable, NULL);
+}
+
+/*
+ * See perf_event_disable();
+ */
+void perf_event_enable(struct perf_event *event)
+{
+	struct perf_event_context *ctx;
+
+	ctx = perf_event_ctx_lock(event);
+	_perf_event_enable(event);
+	perf_event_ctx_unlock(event, ctx);
+}
+EXPORT_SYMBOL_GPL(perf_event_enable);
+
+struct stop_event_data {
+	struct perf_event	*event;
+	unsigned int		restart;
+};
+
+static int __perf_event_stop(void *info)
+{
+	struct stop_event_data *sd = info;
+	struct perf_event *event = sd->event;
+
+	/* if it's already INACTIVE, do nothing */
+	if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
+		return 0;
+
+	/* matches smp_wmb() in event_sched_in() */
+	smp_rmb();
+
+	/*
+	 * There is a window with interrupts enabled before we get here,
+	 * so we need to check again lest we try to stop another CPU's event.
+	 */
+	if (READ_ONCE(event->oncpu) != smp_processor_id())
+		return -EAGAIN;
+
+	event->pmu->stop(event, PERF_EF_UPDATE);
+
+	/*
+	 * May race with the actual stop (through perf_pmu_output_stop()),
+	 * but it is only used for events with AUX ring buffer, and such
+	 * events will refuse to restart because of rb::aux_mmap_count==0,
+	 * see comments in perf_aux_output_begin().
+	 *
+	 * Since this is happening on an event-local CPU, no trace is lost
+	 * while restarting.
+	 */
+	if (sd->restart)
+		event->pmu->start(event, 0);
+
+	return 0;
+}
+
+static int perf_event_stop(struct perf_event *event, int restart)
+{
+	struct stop_event_data sd = {
+		.event		= event,
+		.restart	= restart,
+	};
+	int ret = 0;
+
+	do {
+		if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
+			return 0;
+
+		/* matches smp_wmb() in event_sched_in() */
+		smp_rmb();
+
+		/*
+		 * We only want to restart ACTIVE events, so if the event goes
+		 * inactive here (event->oncpu==-1), there's nothing more to do;
+		 * fall through with ret==-ENXIO.
+		 */
+		ret = cpu_function_call(READ_ONCE(event->oncpu),
+					__perf_event_stop, &sd);
+	} while (ret == -EAGAIN);
+
+	return ret;
+}
+
+/*
+ * In order to contain the amount of racy and tricky in the address filter
+ * configuration management, it is a two part process:
+ *
+ * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
+ *      we update the addresses of corresponding vmas in
+ *	event::addr_filter_ranges array and bump the event::addr_filters_gen;
+ * (p2) when an event is scheduled in (pmu::add), it calls
+ *      perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
+ *      if the generation has changed since the previous call.
+ *
+ * If (p1) happens while the event is active, we restart it to force (p2).
+ *
+ * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
+ *     pre-existing mappings, called once when new filters arrive via SET_FILTER
+ *     ioctl;
+ * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
+ *     registered mapping, called for every new mmap(), with mm::mmap_lock down
+ *     for reading;
+ * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
+ *     of exec.
+ */
+void perf_event_addr_filters_sync(struct perf_event *event)
+{
+	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
+
+	if (!has_addr_filter(event))
+		return;
+
+	raw_spin_lock(&ifh->lock);
+	if (event->addr_filters_gen != event->hw.addr_filters_gen) {
+		event->pmu->addr_filters_sync(event);
+		event->hw.addr_filters_gen = event->addr_filters_gen;
+	}
+	raw_spin_unlock(&ifh->lock);
+}
+EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
+
+static int _perf_event_refresh(struct perf_event *event, int refresh)
+{
+	/*
+	 * not supported on inherited events
+	 */
+	if (event->attr.inherit || !is_sampling_event(event))
+		return -EINVAL;
+
+	atomic_add(refresh, &event->event_limit);
+	_perf_event_enable(event);
+
+	return 0;
+}
+
+/*
+ * See perf_event_disable()
+ */
+int perf_event_refresh(struct perf_event *event, int refresh)
+{
+	struct perf_event_context *ctx;
+	int ret;
+
+	ctx = perf_event_ctx_lock(event);
+	ret = _perf_event_refresh(event, refresh);
+	perf_event_ctx_unlock(event, ctx);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(perf_event_refresh);
+
+static int perf_event_modify_breakpoint(struct perf_event *bp,
+					 struct perf_event_attr *attr)
+{
+	int err;
+
+	_perf_event_disable(bp);
+
+	err = modify_user_hw_breakpoint_check(bp, attr, true);
+
+	if (!bp->attr.disabled)
+		_perf_event_enable(bp);
+
+	return err;
+}
+
+/*
+ * Copy event-type-independent attributes that may be modified.
+ */
+static void perf_event_modify_copy_attr(struct perf_event_attr *to,
+					const struct perf_event_attr *from)
+{
+	to->sig_data = from->sig_data;
+}
+
+static int perf_event_modify_attr(struct perf_event *event,
+				  struct perf_event_attr *attr)
+{
+	int (*func)(struct perf_event *, struct perf_event_attr *);
+	struct perf_event *child;
+	int err;
+
+	if (event->attr.type != attr->type)
+		return -EINVAL;
+
+	switch (event->attr.type) {
+	case PERF_TYPE_BREAKPOINT:
+		func = perf_event_modify_breakpoint;
+		break;
+	default:
+		/* Place holder for future additions. */
+		return -EOPNOTSUPP;
+	}
+
+	WARN_ON_ONCE(event->ctx->parent_ctx);
+
+	mutex_lock(&event->child_mutex);
+	/*
+	 * Event-type-independent attributes must be copied before event-type
+	 * modification, which will validate that final attributes match the
+	 * source attributes after all relevant attributes have been copied.
+	 */
+	perf_event_modify_copy_attr(&event->attr, attr);
+	err = func(event, attr);
+	if (err)
+		goto out;
+	list_for_each_entry(child, &event->child_list, child_list) {
+		perf_event_modify_copy_attr(&child->attr, attr);
+		err = func(child, attr);
+		if (err)
+			goto out;
+	}
+out:
+	mutex_unlock(&event->child_mutex);
+	return err;
+}
+
+static void ctx_sched_out(struct perf_event_context *ctx,
+			  struct perf_cpu_context *cpuctx,
+			  enum event_type_t event_type)
+{
+	struct perf_event *event, *tmp;
+	int is_active = ctx->is_active;
+
+	lockdep_assert_held(&ctx->lock);
+
+	if (likely(!ctx->nr_events)) {
+		/*
+		 * See __perf_remove_from_context().
+		 */
+		WARN_ON_ONCE(ctx->is_active);
+		if (ctx->task)
+			WARN_ON_ONCE(cpuctx->task_ctx);
+		return;
+	}
+
+	/*
+	 * Always update time if it was set; not only when it changes.
+	 * Otherwise we can 'forget' to update time for any but the last
+	 * context we sched out. For example:
+	 *
+	 *   ctx_sched_out(.event_type = EVENT_FLEXIBLE)
+	 *   ctx_sched_out(.event_type = EVENT_PINNED)
+	 *
+	 * would only update time for the pinned events.
+	 */
+	if (is_active & EVENT_TIME) {
+		/* update (and stop) ctx time */
+		update_context_time(ctx);
+		update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx);
+		/*
+		 * CPU-release for the below ->is_active store,
+		 * see __load_acquire() in perf_event_time_now()
+		 */
+		barrier();
+	}
+
+	ctx->is_active &= ~event_type;
+	if (!(ctx->is_active & EVENT_ALL))
+		ctx->is_active = 0;
+
+	if (ctx->task) {
+		WARN_ON_ONCE(cpuctx->task_ctx != ctx);
+		if (!ctx->is_active)
+			cpuctx->task_ctx = NULL;
+	}
+
+	is_active ^= ctx->is_active; /* changed bits */
+
+	if (!ctx->nr_active || !(is_active & EVENT_ALL))
+		return;
+
+	perf_pmu_disable(ctx->pmu);
+	if (is_active & EVENT_PINNED) {
+		list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
+			group_sched_out(event, cpuctx, ctx);
+	}
+
+	if (is_active & EVENT_FLEXIBLE) {
+		list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
+			group_sched_out(event, cpuctx, ctx);
+
+		/*
+		 * Since we cleared EVENT_FLEXIBLE, also clear
+		 * rotate_necessary, is will be reset by
+		 * ctx_flexible_sched_in() when needed.
+		 */
+		ctx->rotate_necessary = 0;
+	}
+	perf_pmu_enable(ctx->pmu);
+}
+
+/*
+ * Test whether two contexts are equivalent, i.e. whether they have both been
+ * cloned from the same version of the same context.
+ *
+ * Equivalence is measured using a generation number in the context that is
+ * incremented on each modification to it; see unclone_ctx(), list_add_event()
+ * and list_del_event().
+ */
+static int context_equiv(struct perf_event_context *ctx1,
+			 struct perf_event_context *ctx2)
+{
+	lockdep_assert_held(&ctx1->lock);
+	lockdep_assert_held(&ctx2->lock);
+
+	/* Pinning disables the swap optimization */
+	if (ctx1->pin_count || ctx2->pin_count)
+		return 0;
+
+	/* If ctx1 is the parent of ctx2 */
+	if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
+		return 1;
+
+	/* If ctx2 is the parent of ctx1 */
+	if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
+		return 1;
+
+	/*
+	 * If ctx1 and ctx2 have the same parent; we flatten the parent
+	 * hierarchy, see perf_event_init_context().
+	 */
+	if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
+			ctx1->parent_gen == ctx2->parent_gen)
+		return 1;
+
+	/* Unmatched */
+	return 0;
+}
+
+static void __perf_event_sync_stat(struct perf_event *event,
+				     struct perf_event *next_event)
+{
+	u64 value;
+
+	if (!event->attr.inherit_stat)
+		return;
+
+	/*
+	 * Update the event value, we cannot use perf_event_read()
+	 * because we're in the middle of a context switch and have IRQs
+	 * disabled, which upsets smp_call_function_single(), however
+	 * we know the event must be on the current CPU, therefore we
+	 * don't need to use it.
+	 */
+	if (event->state == PERF_EVENT_STATE_ACTIVE)
+		event->pmu->read(event);
+
+	perf_event_update_time(event);
+
+	/*
+	 * In order to keep per-task stats reliable we need to flip the event
+	 * values when we flip the contexts.
+	 */
+	value = local64_read(&next_event->count);
+	value = local64_xchg(&event->count, value);
+	local64_set(&next_event->count, value);
+
+	swap(event->total_time_enabled, next_event->total_time_enabled);
+	swap(event->total_time_running, next_event->total_time_running);
+
+	/*
+	 * Since we swizzled the values, update the user visible data too.
+	 */
+	perf_event_update_userpage(event);
+	perf_event_update_userpage(next_event);
+}
+
+static void perf_event_sync_stat(struct perf_event_context *ctx,
+				   struct perf_event_context *next_ctx)
+{
+	struct perf_event *event, *next_event;
+
+	if (!ctx->nr_stat)
+		return;
+
+	update_context_time(ctx);
+
+	event = list_first_entry(&ctx->event_list,
+				   struct perf_event, event_entry);
+
+	next_event = list_first_entry(&next_ctx->event_list,
+					struct perf_event, event_entry);
+
+	while (&event->event_entry != &ctx->event_list &&
+	       &next_event->event_entry != &next_ctx->event_list) {
+
+		__perf_event_sync_stat(event, next_event);
+
+		event = list_next_entry(event, event_entry);
+		next_event = list_next_entry(next_event, event_entry);
+	}
+}
+
+static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
+					 struct task_struct *next)
+{
+	struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
+	struct perf_event_context *next_ctx;
+	struct perf_event_context *parent, *next_parent;
+	struct perf_cpu_context *cpuctx;
+	int do_switch = 1;
+	struct pmu *pmu;
+
+	if (likely(!ctx))
+		return;
+
+	pmu = ctx->pmu;
+	cpuctx = __get_cpu_context(ctx);
+	if (!cpuctx->task_ctx)
+		return;
+
+	rcu_read_lock();
+	next_ctx = next->perf_event_ctxp[ctxn];
+	if (!next_ctx)
+		goto unlock;
+
+	parent = rcu_dereference(ctx->parent_ctx);
+	next_parent = rcu_dereference(next_ctx->parent_ctx);
+
+	/* If neither context have a parent context; they cannot be clones. */
+	if (!parent && !next_parent)
+		goto unlock;
+
+	if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
+		/*
+		 * Looks like the two contexts are clones, so we might be
+		 * able to optimize the context switch.  We lock both
+		 * contexts and check that they are clones under the
+		 * lock (including re-checking that neither has been
+		 * uncloned in the meantime).  It doesn't matter which
+		 * order we take the locks because no other cpu could
+		 * be trying to lock both of these tasks.
+		 */
+		raw_spin_lock(&ctx->lock);
+		raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
+		if (context_equiv(ctx, next_ctx)) {
+
+			perf_pmu_disable(pmu);
+
+			/* PMIs are disabled; ctx->nr_pending is stable. */
+			if (local_read(&ctx->nr_pending) ||
+			    local_read(&next_ctx->nr_pending)) {
+				/*
+				 * Must not swap out ctx when there's pending
+				 * events that rely on the ctx->task relation.
+				 */
+				raw_spin_unlock(&next_ctx->lock);
+				rcu_read_unlock();
+				goto inside_switch;
+			}
+
+			WRITE_ONCE(ctx->task, next);
+			WRITE_ONCE(next_ctx->task, task);
+
+			if (cpuctx->sched_cb_usage && pmu->sched_task)
+				pmu->sched_task(ctx, false);
+
+			/*
+			 * PMU specific parts of task perf context can require
+			 * additional synchronization. As an example of such
+			 * synchronization see implementation details of Intel
+			 * LBR call stack data profiling;
+			 */
+			if (pmu->swap_task_ctx)
+				pmu->swap_task_ctx(ctx, next_ctx);
+			else
+				swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
+
+			perf_pmu_enable(pmu);
+
+			/*
+			 * RCU_INIT_POINTER here is safe because we've not
+			 * modified the ctx and the above modification of
+			 * ctx->task and ctx->task_ctx_data are immaterial
+			 * since those values are always verified under
+			 * ctx->lock which we're now holding.
+			 */
+			RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
+			RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
+
+			do_switch = 0;
+
+			perf_event_sync_stat(ctx, next_ctx);
+		}
+		raw_spin_unlock(&next_ctx->lock);
+		raw_spin_unlock(&ctx->lock);
+	}
+unlock:
+	rcu_read_unlock();
+
+	if (do_switch) {
+		raw_spin_lock(&ctx->lock);
+		perf_pmu_disable(pmu);
+
+inside_switch:
+		if (cpuctx->sched_cb_usage && pmu->sched_task)
+			pmu->sched_task(ctx, false);
+		task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
+
+		perf_pmu_enable(pmu);
+		raw_spin_unlock(&ctx->lock);
+	}
+}
+
+static DEFINE_PER_CPU(struct list_head, sched_cb_list);
+
+void perf_sched_cb_dec(struct pmu *pmu)
+{
+	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+
+	this_cpu_dec(perf_sched_cb_usages);
+
+	if (!--cpuctx->sched_cb_usage)
+		list_del(&cpuctx->sched_cb_entry);
+}
+
+
+void perf_sched_cb_inc(struct pmu *pmu)
+{
+	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+
+	if (!cpuctx->sched_cb_usage++)
+		list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
+
+	this_cpu_inc(perf_sched_cb_usages);
+}
+
+/*
+ * This function provides the context switch callback to the lower code
+ * layer. It is invoked ONLY when the context switch callback is enabled.
+ *
+ * This callback is relevant even to per-cpu events; for example multi event
+ * PEBS requires this to provide PID/TID information. This requires we flush
+ * all queued PEBS records before we context switch to a new task.
+ */
+static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in)
+{
+	struct pmu *pmu;
+
+	pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
+
+	if (WARN_ON_ONCE(!pmu->sched_task))
+		return;
+
+	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
+	perf_pmu_disable(pmu);
+
+	pmu->sched_task(cpuctx->task_ctx, sched_in);
+
+	perf_pmu_enable(pmu);
+	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
+}
+
+static void perf_pmu_sched_task(struct task_struct *prev,
+				struct task_struct *next,
+				bool sched_in)
+{
+	struct perf_cpu_context *cpuctx;
+
+	if (prev == next)
+		return;
+
+	list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
+		/* will be handled in perf_event_context_sched_in/out */
+		if (cpuctx->task_ctx)
+			continue;
+
+		__perf_pmu_sched_task(cpuctx, sched_in);
+	}
+}
+
+static void perf_event_switch(struct task_struct *task,
+			      struct task_struct *next_prev, bool sched_in);
+
+#define for_each_task_context_nr(ctxn)					\
+	for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
+
+/*
+ * Called from scheduler to remove the events of the current task,
+ * with interrupts disabled.
+ *
+ * We stop each event and update the event value in event->count.
+ *
+ * This does not protect us against NMI, but disable()
+ * sets the disabled bit in the control field of event _before_
+ * accessing the event control register. If a NMI hits, then it will
+ * not restart the event.
+ */
+void __perf_event_task_sched_out(struct task_struct *task,
+				 struct task_struct *next)
+{
+	int ctxn;
+
+	if (__this_cpu_read(perf_sched_cb_usages))
+		perf_pmu_sched_task(task, next, false);
+
+	if (atomic_read(&nr_switch_events))
+		perf_event_switch(task, next, false);
+
+	for_each_task_context_nr(ctxn)
+		perf_event_context_sched_out(task, ctxn, next);
+
+	/*
+	 * if cgroup events exist on this CPU, then we need
+	 * to check if we have to switch out PMU state.
+	 * cgroup event are system-wide mode only
+	 */
+	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
+		perf_cgroup_switch(next);
+}
+
+/*
+ * Called with IRQs disabled
+ */
+static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
+			      enum event_type_t event_type)
+{
+	ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
+}
+
+static bool perf_less_group_idx(const void *l, const void *r)
+{
+	const struct perf_event *le = *(const struct perf_event **)l;
+	const struct perf_event *re = *(const struct perf_event **)r;
+
+	return le->group_index < re->group_index;
+}
+
+static void swap_ptr(void *l, void *r)
+{
+	void **lp = l, **rp = r;
+
+	swap(*lp, *rp);
+}
+
+static const struct min_heap_callbacks perf_min_heap = {
+	.elem_size = sizeof(struct perf_event *),
+	.less = perf_less_group_idx,
+	.swp = swap_ptr,
+};
+
+static void __heap_add(struct min_heap *heap, struct perf_event *event)
+{
+	struct perf_event **itrs = heap->data;
+
+	if (event) {
+		itrs[heap->nr] = event;
+		heap->nr++;
+	}
+}
+
+static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
+				struct perf_event_groups *groups, int cpu,
+				int (*func)(struct perf_event *, void *),
+				void *data)
+{
+#ifdef CONFIG_CGROUP_PERF
+	struct cgroup_subsys_state *css = NULL;
+#endif
+	/* Space for per CPU and/or any CPU event iterators. */
+	struct perf_event *itrs[2];
+	struct min_heap event_heap;
+	struct perf_event **evt;
+	int ret;
+
+	if (cpuctx) {
+		event_heap = (struct min_heap){
+			.data = cpuctx->heap,
+			.nr = 0,
+			.size = cpuctx->heap_size,
+		};
+
+		lockdep_assert_held(&cpuctx->ctx.lock);
+
+#ifdef CONFIG_CGROUP_PERF
+		if (cpuctx->cgrp)
+			css = &cpuctx->cgrp->css;
+#endif
+	} else {
+		event_heap = (struct min_heap){
+			.data = itrs,
+			.nr = 0,
+			.size = ARRAY_SIZE(itrs),
+		};
+		/* Events not within a CPU context may be on any CPU. */
+		__heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
+	}
+	evt = event_heap.data;
+
+	__heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
+
+#ifdef CONFIG_CGROUP_PERF
+	for (; css; css = css->parent)
+		__heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
+#endif
+
+	min_heapify_all(&event_heap, &perf_min_heap);
+
+	while (event_heap.nr) {
+		ret = func(*evt, data);
+		if (ret)
+			return ret;
+
+		*evt = perf_event_groups_next(*evt);
+		if (*evt)
+			min_heapify(&event_heap, 0, &perf_min_heap);
+		else
+			min_heap_pop(&event_heap, &perf_min_heap);
+	}
+
+	return 0;
+}
+
+/*
+ * Because the userpage is strictly per-event (there is no concept of context,
+ * so there cannot be a context indirection), every userpage must be updated
+ * when context time starts :-(
+ *
+ * IOW, we must not miss EVENT_TIME edges.
+ */
+static inline bool event_update_userpage(struct perf_event *event)
+{
+	if (likely(!atomic_read(&event->mmap_count)))
+		return false;
+
+	perf_event_update_time(event);
+	perf_event_update_userpage(event);
+
+	return true;
+}
+
+static inline void group_update_userpage(struct perf_event *group_event)
+{
+	struct perf_event *event;
+
+	if (!event_update_userpage(group_event))
+		return;
+
+	for_each_sibling_event(event, group_event)
+		event_update_userpage(event);
+}
+
+static int merge_sched_in(struct perf_event *event, void *data)
+{
+	struct perf_event_context *ctx = event->ctx;
+	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+	int *can_add_hw = data;
+
+	if (event->state <= PERF_EVENT_STATE_OFF)
+		return 0;
+
+	if (!event_filter_match(event))
+		return 0;
+
+	if (group_can_go_on(event, cpuctx, *can_add_hw)) {
+		if (!group_sched_in(event, cpuctx, ctx))
+			list_add_tail(&event->active_list, get_event_list(event));
+	}
+
+	if (event->state == PERF_EVENT_STATE_INACTIVE) {
+		*can_add_hw = 0;
+		if (event->attr.pinned) {
+			perf_cgroup_event_disable(event, ctx);
+			perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
+		} else {
+			ctx->rotate_necessary = 1;
+			perf_mux_hrtimer_restart(cpuctx);
+			group_update_userpage(event);
+		}
+	}
+
+	return 0;
+}
+
+static void
+ctx_pinned_sched_in(struct perf_event_context *ctx,
+		    struct perf_cpu_context *cpuctx)
+{
+	int can_add_hw = 1;
+
+	if (ctx != &cpuctx->ctx)
+		cpuctx = NULL;
+
+	visit_groups_merge(cpuctx, &ctx->pinned_groups,
+			   smp_processor_id(),
+			   merge_sched_in, &can_add_hw);
+}
+
+static void
+ctx_flexible_sched_in(struct perf_event_context *ctx,
+		      struct perf_cpu_context *cpuctx)
+{
+	int can_add_hw = 1;
+
+	if (ctx != &cpuctx->ctx)
+		cpuctx = NULL;
+
+	visit_groups_merge(cpuctx, &ctx->flexible_groups,
+			   smp_processor_id(),
+			   merge_sched_in, &can_add_hw);
+}
+
+static void
+ctx_sched_in(struct perf_event_context *ctx,
+	     struct perf_cpu_context *cpuctx,
+	     enum event_type_t event_type)
+{
+	int is_active = ctx->is_active;
+
+	lockdep_assert_held(&ctx->lock);
+
+	if (likely(!ctx->nr_events))
+		return;
+
+	if (!(is_active & EVENT_TIME)) {
+		/* start ctx time */
+		__update_context_time(ctx, false);
+		perf_cgroup_set_timestamp(cpuctx);
+		/*
+		 * CPU-release for the below ->is_active store,
+		 * see __load_acquire() in perf_event_time_now()
+		 */
+		barrier();
+	}
+
+	ctx->is_active |= (event_type | EVENT_TIME);
+	if (ctx->task) {
+		if (!is_active)
+			cpuctx->task_ctx = ctx;
+		else
+			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
+	}
+
+	is_active ^= ctx->is_active; /* changed bits */
+
+	/*
+	 * First go through the list and put on any pinned groups
+	 * in order to give them the best chance of going on.
+	 */
+	if (is_active & EVENT_PINNED)
+		ctx_pinned_sched_in(ctx, cpuctx);
+
+	/* Then walk through the lower prio flexible groups */
+	if (is_active & EVENT_FLEXIBLE)
+		ctx_flexible_sched_in(ctx, cpuctx);
+}
+
+static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
+			     enum event_type_t event_type)
+{
+	struct perf_event_context *ctx = &cpuctx->ctx;
+
+	ctx_sched_in(ctx, cpuctx, event_type);
+}
+
+static void perf_event_context_sched_in(struct perf_event_context *ctx,
+					struct task_struct *task)
+{
+	struct perf_cpu_context *cpuctx;
+	struct pmu *pmu;
+
+	cpuctx = __get_cpu_context(ctx);
+
+	/*
+	 * HACK: for HETEROGENEOUS the task context might have switched to a
+	 * different PMU, force (re)set the context,
+	 */
+	pmu = ctx->pmu = cpuctx->ctx.pmu;
+
+	if (cpuctx->task_ctx == ctx) {
+		if (cpuctx->sched_cb_usage)
+			__perf_pmu_sched_task(cpuctx, true);
+		return;
+	}
+
+	perf_ctx_lock(cpuctx, ctx);
+	/*
+	 * We must check ctx->nr_events while holding ctx->lock, such
+	 * that we serialize against perf_install_in_context().
+	 */
+	if (!ctx->nr_events)
+		goto unlock;
+
+	perf_pmu_disable(pmu);
+	/*
+	 * We want to keep the following priority order:
+	 * cpu pinned (that don't need to move), task pinned,
+	 * cpu flexible, task flexible.
+	 *
+	 * However, if task's ctx is not carrying any pinned
+	 * events, no need to flip the cpuctx's events around.
+	 */
+	if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
+		cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
+	perf_event_sched_in(cpuctx, ctx);
+
+	if (cpuctx->sched_cb_usage && pmu->sched_task)
+		pmu->sched_task(cpuctx->task_ctx, true);
+
+	perf_pmu_enable(pmu);
+
+unlock:
+	perf_ctx_unlock(cpuctx, ctx);
+}
+
+/*
+ * Called from scheduler to add the events of the current task
+ * with interrupts disabled.
+ *
+ * We restore the event value and then enable it.
+ *
+ * This does not protect us against NMI, but enable()
+ * sets the enabled bit in the control field of event _before_
+ * accessing the event control register. If a NMI hits, then it will
+ * keep the event running.
+ */
+void __perf_event_task_sched_in(struct task_struct *prev,
+				struct task_struct *task)
+{
+	struct perf_event_context *ctx;
+	int ctxn;
+
+	for_each_task_context_nr(ctxn) {
+		ctx = task->perf_event_ctxp[ctxn];
+		if (likely(!ctx))
+			continue;
+
+		perf_event_context_sched_in(ctx, task);
+	}
+
+	if (atomic_read(&nr_switch_events))
+		perf_event_switch(task, prev, true);
+
+	if (__this_cpu_read(perf_sched_cb_usages))
+		perf_pmu_sched_task(prev, task, true);
+}
+
+static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
+{
+	u64 frequency = event->attr.sample_freq;
+	u64 sec = NSEC_PER_SEC;
+	u64 divisor, dividend;
+
+	int count_fls, nsec_fls, frequency_fls, sec_fls;
+
+	count_fls = fls64(count);
+	nsec_fls = fls64(nsec);
+	frequency_fls = fls64(frequency);
+	sec_fls = 30;
+
+	/*
+	 * We got @count in @nsec, with a target of sample_freq HZ
+	 * the target period becomes:
+	 *
+	 *             @count * 10^9
+	 * period = -------------------
+	 *          @nsec * sample_freq
+	 *
+	 */
+
+	/*
+	 * Reduce accuracy by one bit such that @a and @b converge
+	 * to a similar magnitude.
+	 */
+#define REDUCE_FLS(a, b)		\
+do {					\
+	if (a##_fls > b##_fls) {	\
+		a >>= 1;		\
+		a##_fls--;		\
+	} else {			\
+		b >>= 1;		\
+		b##_fls--;		\
+	}				\
+} while (0)
+
+	/*
+	 * Reduce accuracy until either term fits in a u64, then proceed with
+	 * the other, so that finally we can do a u64/u64 division.
+	 */
+	while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
+		REDUCE_FLS(nsec, frequency);
+		REDUCE_FLS(sec, count);
+	}
+
+	if (count_fls + sec_fls > 64) {
+		divisor = nsec * frequency;
+
+		while (count_fls + sec_fls > 64) {
+			REDUCE_FLS(count, sec);
+			divisor >>= 1;
+		}
+
+		dividend = count * sec;
+	} else {
+		dividend = count * sec;
+
+		while (nsec_fls + frequency_fls > 64) {
+			REDUCE_FLS(nsec, frequency);
+			dividend >>= 1;
+		}
+
+		divisor = nsec * frequency;
+	}
+
+	if (!divisor)
+		return dividend;
+
+	return div64_u64(dividend, divisor);
+}
+
+static DEFINE_PER_CPU(int, perf_throttled_count);
+static DEFINE_PER_CPU(u64, perf_throttled_seq);
+
+static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	s64 period, sample_period;
+	s64 delta;
+
+	period = perf_calculate_period(event, nsec, count);
+
+	delta = (s64)(period - hwc->sample_period);
+	delta = (delta + 7) / 8; /* low pass filter */
+
+	sample_period = hwc->sample_period + delta;
+
+	if (!sample_period)
+		sample_period = 1;
+
+	hwc->sample_period = sample_period;
+
+	if (local64_read(&hwc->period_left) > 8*sample_period) {
+		if (disable)
+			event->pmu->stop(event, PERF_EF_UPDATE);
+
+		local64_set(&hwc->period_left, 0);
+
+		if (disable)
+			event->pmu->start(event, PERF_EF_RELOAD);
+	}
+}
+
+/*
+ * combine freq adjustment with unthrottling to avoid two passes over the
+ * events. At the same time, make sure, having freq events does not change
+ * the rate of unthrottling as that would introduce bias.
+ */
+static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
+					   int needs_unthr)
+{
+	struct perf_event *event;
+	struct hw_perf_event *hwc;
+	u64 now, period = TICK_NSEC;
+	s64 delta;
+
+	/*
+	 * only need to iterate over all events iff:
+	 * - context have events in frequency mode (needs freq adjust)
+	 * - there are events to unthrottle on this cpu
+	 */
+	if (!(ctx->nr_freq || needs_unthr))
+		return;
+
+	raw_spin_lock(&ctx->lock);
+	perf_pmu_disable(ctx->pmu);
+
+	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+		if (event->state != PERF_EVENT_STATE_ACTIVE)
+			continue;
+
+		if (!event_filter_match(event))
+			continue;
+
+		perf_pmu_disable(event->pmu);
+
+		hwc = &event->hw;
+
+		if (hwc->interrupts == MAX_INTERRUPTS) {
+			hwc->interrupts = 0;
+			perf_log_throttle(event, 1);
+			event->pmu->start(event, 0);
+		}
+
+		if (!event->attr.freq || !event->attr.sample_freq)
+			goto next;
+
+		/*
+		 * stop the event and update event->count
+		 */
+		event->pmu->stop(event, PERF_EF_UPDATE);
+
+		now = local64_read(&event->count);
+		delta = now - hwc->freq_count_stamp;
+		hwc->freq_count_stamp = now;
+
+		/*
+		 * restart the event
+		 * reload only if value has changed
+		 * we have stopped the event so tell that
+		 * to perf_adjust_period() to avoid stopping it
+		 * twice.
+		 */
+		if (delta > 0)
+			perf_adjust_period(event, period, delta, false);
+
+		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
+	next:
+		perf_pmu_enable(event->pmu);
+	}
+
+	perf_pmu_enable(ctx->pmu);
+	raw_spin_unlock(&ctx->lock);
+}
+
+/*
+ * Move @event to the tail of the @ctx's elegible events.
+ */
+static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
+{
+	/*
+	 * Rotate the first entry last of non-pinned groups. Rotation might be
+	 * disabled by the inheritance code.
+	 */
+	if (ctx->rotate_disable)
+		return;
+
+	perf_event_groups_delete(&ctx->flexible_groups, event);
+	perf_event_groups_insert(&ctx->flexible_groups, event);
+}
+
+/* pick an event from the flexible_groups to rotate */
+static inline struct perf_event *
+ctx_event_to_rotate(struct perf_event_context *ctx)
+{
+	struct perf_event *event;
+
+	/* pick the first active flexible event */
+	event = list_first_entry_or_null(&ctx->flexible_active,
+					 struct perf_event, active_list);
+
+	/* if no active flexible event, pick the first event */
+	if (!event) {
+		event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
+				      typeof(*event), group_node);
+	}
+
+	/*
+	 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
+	 * finds there are unschedulable events, it will set it again.
+	 */
+	ctx->rotate_necessary = 0;
+
+	return event;
+}
+
+static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
+{
+	struct perf_event *cpu_event = NULL, *task_event = NULL;
+	struct perf_event_context *task_ctx = NULL;
+	int cpu_rotate, task_rotate;
+
+	/*
+	 * Since we run this from IRQ context, nobody can install new
+	 * events, thus the event count values are stable.
+	 */
+
+	cpu_rotate = cpuctx->ctx.rotate_necessary;
+	task_ctx = cpuctx->task_ctx;
+	task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
+
+	if (!(cpu_rotate || task_rotate))
+		return false;
+
+	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
+	perf_pmu_disable(cpuctx->ctx.pmu);
+
+	if (task_rotate)
+		task_event = ctx_event_to_rotate(task_ctx);
+	if (cpu_rotate)
+		cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
+
+	/*
+	 * As per the order given at ctx_resched() first 'pop' task flexible
+	 * and then, if needed CPU flexible.
+	 */
+	if (task_event || (task_ctx && cpu_event))
+		ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
+	if (cpu_event)
+		cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
+
+	if (task_event)
+		rotate_ctx(task_ctx, task_event);
+	if (cpu_event)
+		rotate_ctx(&cpuctx->ctx, cpu_event);
+
+	perf_event_sched_in(cpuctx, task_ctx);
+
+	perf_pmu_enable(cpuctx->ctx.pmu);
+	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
+
+	return true;
+}
+
+void perf_event_task_tick(void)
+{
+	struct list_head *head = this_cpu_ptr(&active_ctx_list);
+	struct perf_event_context *ctx, *tmp;
+	int throttled;
+
+	lockdep_assert_irqs_disabled();
+
+	__this_cpu_inc(perf_throttled_seq);
+	throttled = __this_cpu_xchg(perf_throttled_count, 0);
+	tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
+
+	list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
+		perf_adjust_freq_unthr_context(ctx, throttled);
+}
+
+static int event_enable_on_exec(struct perf_event *event,
+				struct perf_event_context *ctx)
+{
+	if (!event->attr.enable_on_exec)
+		return 0;
+
+	event->attr.enable_on_exec = 0;
+	if (event->state >= PERF_EVENT_STATE_INACTIVE)
+		return 0;
+
+	perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
+
+	return 1;
+}
+
+/*
+ * Enable all of a task's events that have been marked enable-on-exec.
+ * This expects task == current.
+ */
+static void perf_event_enable_on_exec(int ctxn)
+{
+	struct perf_event_context *ctx, *clone_ctx = NULL;
+	enum event_type_t event_type = 0;
+	struct perf_cpu_context *cpuctx;
+	struct perf_event *event;
+	unsigned long flags;
+	int enabled = 0;
+
+	local_irq_save(flags);
+	ctx = current->perf_event_ctxp[ctxn];
+	if (!ctx || !ctx->nr_events)
+		goto out;
+
+	cpuctx = __get_cpu_context(ctx);
+	perf_ctx_lock(cpuctx, ctx);
+	ctx_sched_out(ctx, cpuctx, EVENT_TIME);
+	list_for_each_entry(event, &ctx->event_list, event_entry) {
+		enabled |= event_enable_on_exec(event, ctx);
+		event_type |= get_event_type(event);
+	}
+
+	/*
+	 * Unclone and reschedule this context if we enabled any event.
+	 */
+	if (enabled) {
+		clone_ctx = unclone_ctx(ctx);
+		ctx_resched(cpuctx, ctx, event_type);
+	} else {
+		ctx_sched_in(ctx, cpuctx, EVENT_TIME);
+	}
+	perf_ctx_unlock(cpuctx, ctx);
+
+out:
+	local_irq_restore(flags);
+
+	if (clone_ctx)
+		put_ctx(clone_ctx);
+}
+
+static void perf_remove_from_owner(struct perf_event *event);
+static void perf_event_exit_event(struct perf_event *event,
+				  struct perf_event_context *ctx);
+
+/*
+ * Removes all events from the current task that have been marked
+ * remove-on-exec, and feeds their values back to parent events.
+ */
+static void perf_event_remove_on_exec(int ctxn)
+{
+	struct perf_event_context *ctx, *clone_ctx = NULL;
+	struct perf_event *event, *next;
+	unsigned long flags;
+	bool modified = false;
+
+	ctx = perf_pin_task_context(current, ctxn);
+	if (!ctx)
+		return;
+
+	mutex_lock(&ctx->mutex);
+
+	if (WARN_ON_ONCE(ctx->task != current))
+		goto unlock;
+
+	list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
+		if (!event->attr.remove_on_exec)
+			continue;
+
+		if (!is_kernel_event(event))
+			perf_remove_from_owner(event);
+
+		modified = true;
+
+		perf_event_exit_event(event, ctx);
+	}
+
+	raw_spin_lock_irqsave(&ctx->lock, flags);
+	if (modified)
+		clone_ctx = unclone_ctx(ctx);
+	--ctx->pin_count;
+	raw_spin_unlock_irqrestore(&ctx->lock, flags);
+
+unlock:
+	mutex_unlock(&ctx->mutex);
+
+	put_ctx(ctx);
+	if (clone_ctx)
+		put_ctx(clone_ctx);
+}
+
+struct perf_read_data {
+	struct perf_event *event;
+	bool group;
+	int ret;
+};
+
+static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
+{
+	u16 local_pkg, event_pkg;
+
+	if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
+		int local_cpu = smp_processor_id();
+
+		event_pkg = topology_physical_package_id(event_cpu);
+		local_pkg = topology_physical_package_id(local_cpu);
+
+		if (event_pkg == local_pkg)
+			return local_cpu;
+	}
+
+	return event_cpu;
+}
+
+/*
+ * Cross CPU call to read the hardware event
+ */
+static void __perf_event_read(void *info)
+{
+	struct perf_read_data *data = info;
+	struct perf_event *sub, *event = data->event;
+	struct perf_event_context *ctx = event->ctx;
+	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+	struct pmu *pmu = event->pmu;
+
+	/*
+	 * If this is a task context, we need to check whether it is
+	 * the current task context of this cpu.  If not it has been
+	 * scheduled out before the smp call arrived.  In that case
+	 * event->count would have been updated to a recent sample
+	 * when the event was scheduled out.
+	 */
+	if (ctx->task && cpuctx->task_ctx != ctx)
+		return;
+
+	raw_spin_lock(&ctx->lock);
+	if (ctx->is_active & EVENT_TIME) {
+		update_context_time(ctx);
+		update_cgrp_time_from_event(event);
+	}
+
+	perf_event_update_time(event);
+	if (data->group)
+		perf_event_update_sibling_time(event);
+
+	if (event->state != PERF_EVENT_STATE_ACTIVE)
+		goto unlock;
+
+	if (!data->group) {
+		pmu->read(event);
+		data->ret = 0;
+		goto unlock;
+	}
+
+	pmu->start_txn(pmu, PERF_PMU_TXN_READ);
+
+	pmu->read(event);
+
+	for_each_sibling_event(sub, event) {
+		if (sub->state == PERF_EVENT_STATE_ACTIVE) {
+			/*
+			 * Use sibling's PMU rather than @event's since
+			 * sibling could be on different (eg: software) PMU.
+			 */
+			sub->pmu->read(sub);
+		}
+	}
+
+	data->ret = pmu->commit_txn(pmu);
+
+unlock:
+	raw_spin_unlock(&ctx->lock);
+}
+
+static inline u64 perf_event_count(struct perf_event *event)
+{
+	return local64_read(&event->count) + atomic64_read(&event->child_count);
+}
+
+static void calc_timer_values(struct perf_event *event,
+				u64 *now,
+				u64 *enabled,
+				u64 *running)
+{
+	u64 ctx_time;
+
+	*now = perf_clock();
+	ctx_time = perf_event_time_now(event, *now);
+	__perf_update_times(event, ctx_time, enabled, running);
+}
+
+/*
+ * NMI-safe method to read a local event, that is an event that
+ * is:
+ *   - either for the current task, or for this CPU
+ *   - does not have inherit set, for inherited task events
+ *     will not be local and we cannot read them atomically
+ *   - must not have a pmu::count method
+ */
+int perf_event_read_local(struct perf_event *event, u64 *value,
+			  u64 *enabled, u64 *running)
+{
+	unsigned long flags;
+	int ret = 0;
+
+	/*
+	 * Disabling interrupts avoids all counter scheduling (context
+	 * switches, timer based rotation and IPIs).
+	 */
+	local_irq_save(flags);
+
+	/*
+	 * It must not be an event with inherit set, we cannot read
+	 * all child counters from atomic context.
+	 */
+	if (event->attr.inherit) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	/* If this is a per-task event, it must be for current */
+	if ((event->attach_state & PERF_ATTACH_TASK) &&
+	    event->hw.target != current) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* If this is a per-CPU event, it must be for this CPU */
+	if (!(event->attach_state & PERF_ATTACH_TASK) &&
+	    event->cpu != smp_processor_id()) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* If this is a pinned event it must be running on this CPU */
+	if (event->attr.pinned && event->oncpu != smp_processor_id()) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	/*
+	 * If the event is currently on this CPU, its either a per-task event,
+	 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
+	 * oncpu == -1).
+	 */
+	if (event->oncpu == smp_processor_id())
+		event->pmu->read(event);
+
+	*value = local64_read(&event->count);
+	if (enabled || running) {
+		u64 __enabled, __running, __now;
+
+		calc_timer_values(event, &__now, &__enabled, &__running);
+		if (enabled)
+			*enabled = __enabled;
+		if (running)
+			*running = __running;
+	}
+out:
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static int perf_event_read(struct perf_event *event, bool group)
+{
+	enum perf_event_state state = READ_ONCE(event->state);
+	int event_cpu, ret = 0;
+
+	/*
+	 * If event is enabled and currently active on a CPU, update the
+	 * value in the event structure:
+	 */
+again:
+	if (state == PERF_EVENT_STATE_ACTIVE) {
+		struct perf_read_data data;
+
+		/*
+		 * Orders the ->state and ->oncpu loads such that if we see
+		 * ACTIVE we must also see the right ->oncpu.
+		 *
+		 * Matches the smp_wmb() from event_sched_in().
+		 */
+		smp_rmb();
+
+		event_cpu = READ_ONCE(event->oncpu);
+		if ((unsigned)event_cpu >= nr_cpu_ids)
+			return 0;
+
+		data = (struct perf_read_data){
+			.event = event,
+			.group = group,
+			.ret = 0,
+		};
+
+		preempt_disable();
+		event_cpu = __perf_event_read_cpu(event, event_cpu);
+
+		/*
+		 * Purposely ignore the smp_call_function_single() return
+		 * value.
+		 *
+		 * If event_cpu isn't a valid CPU it means the event got
+		 * scheduled out and that will have updated the event count.
+		 *
+		 * Therefore, either way, we'll have an up-to-date event count
+		 * after this.
+		 */
+		(void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
+		preempt_enable();
+		ret = data.ret;
+
+	} else if (state == PERF_EVENT_STATE_INACTIVE) {
+		struct perf_event_context *ctx = event->ctx;
+		unsigned long flags;
+
+		raw_spin_lock_irqsave(&ctx->lock, flags);
+		state = event->state;
+		if (state != PERF_EVENT_STATE_INACTIVE) {
+			raw_spin_unlock_irqrestore(&ctx->lock, flags);
+			goto again;
+		}
+
+		/*
+		 * May read while context is not active (e.g., thread is
+		 * blocked), in that case we cannot update context time
+		 */
+		if (ctx->is_active & EVENT_TIME) {
+			update_context_time(ctx);
+			update_cgrp_time_from_event(event);
+		}
+
+		perf_event_update_time(event);
+		if (group)
+			perf_event_update_sibling_time(event);
+		raw_spin_unlock_irqrestore(&ctx->lock, flags);
+	}
+
+	return ret;
+}
+
+/*
+ * Initialize the perf_event context in a task_struct:
+ */
+static void __perf_event_init_context(struct perf_event_context *ctx)
+{
+	raw_spin_lock_init(&ctx->lock);
+	mutex_init(&ctx->mutex);
+	INIT_LIST_HEAD(&ctx->active_ctx_list);
+	perf_event_groups_init(&ctx->pinned_groups);
+	perf_event_groups_init(&ctx->flexible_groups);
+	INIT_LIST_HEAD(&ctx->event_list);
+	INIT_LIST_HEAD(&ctx->pinned_active);
+	INIT_LIST_HEAD(&ctx->flexible_active);
+	refcount_set(&ctx->refcount, 1);
+}
+
+static struct perf_event_context *
+alloc_perf_context(struct pmu *pmu, struct task_struct *task)
+{
+	struct perf_event_context *ctx;
+
+	ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
+	if (!ctx)
+		return NULL;
+
+	__perf_event_init_context(ctx);
+	if (task)
+		ctx->task = get_task_struct(task);
+	ctx->pmu = pmu;
+
+	return ctx;
+}
+
+static struct task_struct *
+find_lively_task_by_vpid(pid_t vpid)
+{
+	struct task_struct *task;
+
+	rcu_read_lock();
+	if (!vpid)
+		task = current;
+	else
+		task = find_task_by_vpid(vpid);
+	if (task)
+		get_task_struct(task);
+	rcu_read_unlock();
+
+	if (!task)
+		return ERR_PTR(-ESRCH);
+
+	return task;
+}
+
+/*
+ * Returns a matching context with refcount and pincount.
+ */
+static struct perf_event_context *
+find_get_context(struct pmu *pmu, struct task_struct *task,
+		struct perf_event *event)
+{
+	struct perf_event_context *ctx, *clone_ctx = NULL;
+	struct perf_cpu_context *cpuctx;
+	void *task_ctx_data = NULL;
+	unsigned long flags;
+	int ctxn, err;
+	int cpu = event->cpu;
+
+	if (!task) {
+		/* Must be root to operate on a CPU event: */
+		err = perf_allow_cpu(&event->attr);
+		if (err)
+			return ERR_PTR(err);
+
+		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
+		ctx = &cpuctx->ctx;
+		get_ctx(ctx);
+		raw_spin_lock_irqsave(&ctx->lock, flags);
+		++ctx->pin_count;
+		raw_spin_unlock_irqrestore(&ctx->lock, flags);
+
+		return ctx;
+	}
+
+	err = -EINVAL;
+	ctxn = pmu->task_ctx_nr;
+	if (ctxn < 0)
+		goto errout;
+
+	if (event->attach_state & PERF_ATTACH_TASK_DATA) {
+		task_ctx_data = alloc_task_ctx_data(pmu);
+		if (!task_ctx_data) {
+			err = -ENOMEM;
+			goto errout;
+		}
+	}
+
+retry:
+	ctx = perf_lock_task_context(task, ctxn, &flags);
+	if (ctx) {
+		clone_ctx = unclone_ctx(ctx);
+		++ctx->pin_count;
+
+		if (task_ctx_data && !ctx->task_ctx_data) {
+			ctx->task_ctx_data = task_ctx_data;
+			task_ctx_data = NULL;
+		}
+		raw_spin_unlock_irqrestore(&ctx->lock, flags);
+
+		if (clone_ctx)
+			put_ctx(clone_ctx);
+	} else {
+		ctx = alloc_perf_context(pmu, task);
+		err = -ENOMEM;
+		if (!ctx)
+			goto errout;
+
+		if (task_ctx_data) {
+			ctx->task_ctx_data = task_ctx_data;
+			task_ctx_data = NULL;
+		}
+
+		err = 0;
+		mutex_lock(&task->perf_event_mutex);
+		/*
+		 * If it has already passed perf_event_exit_task().
+		 * we must see PF_EXITING, it takes this mutex too.
+		 */
+		if (task->flags & PF_EXITING)
+			err = -ESRCH;
+		else if (task->perf_event_ctxp[ctxn])
+			err = -EAGAIN;
+		else {
+			get_ctx(ctx);
+			++ctx->pin_count;
+			rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
+		}
+		mutex_unlock(&task->perf_event_mutex);
+
+		if (unlikely(err)) {
+			put_ctx(ctx);
+
+			if (err == -EAGAIN)
+				goto retry;
+			goto errout;
+		}
+	}
+
+	free_task_ctx_data(pmu, task_ctx_data);
+	return ctx;
+
+errout:
+	free_task_ctx_data(pmu, task_ctx_data);
+	return ERR_PTR(err);
+}
+
+static void perf_event_free_filter(struct perf_event *event);
+
+static void free_event_rcu(struct rcu_head *head)
+{
+	struct perf_event *event;
+
+	event = container_of(head, struct perf_event, rcu_head);
+	if (event->ns)
+		put_pid_ns(event->ns);
+	perf_event_free_filter(event);
+	kmem_cache_free(perf_event_cache, event);
+}
+
+static void ring_buffer_attach(struct perf_event *event,
+			       struct perf_buffer *rb);
+
+static void detach_sb_event(struct perf_event *event)
+{
+	struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
+
+	raw_spin_lock(&pel->lock);
+	list_del_rcu(&event->sb_list);
+	raw_spin_unlock(&pel->lock);
+}
+
+static bool is_sb_event(struct perf_event *event)
+{
+	struct perf_event_attr *attr = &event->attr;
+
+	if (event->parent)
+		return false;
+
+	if (event->attach_state & PERF_ATTACH_TASK)
+		return false;
+
+	if (attr->mmap || attr->mmap_data || attr->mmap2 ||
+	    attr->comm || attr->comm_exec ||
+	    attr->task || attr->ksymbol ||
+	    attr->context_switch || attr->text_poke ||
+	    attr->bpf_event)
+		return true;
+	return false;
+}
+
+static void unaccount_pmu_sb_event(struct perf_event *event)
+{
+	if (is_sb_event(event))
+		detach_sb_event(event);
+}
+
+static void unaccount_event_cpu(struct perf_event *event, int cpu)
+{
+	if (event->parent)
+		return;
+
+	if (is_cgroup_event(event))
+		atomic_dec(&per_cpu(perf_cgroup_events, cpu));
+}
+
+#ifdef CONFIG_NO_HZ_FULL
+static DEFINE_SPINLOCK(nr_freq_lock);
+#endif
+
+static void unaccount_freq_event_nohz(void)
+{
+#ifdef CONFIG_NO_HZ_FULL
+	spin_lock(&nr_freq_lock);
+	if (atomic_dec_and_test(&nr_freq_events))
+		tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
+	spin_unlock(&nr_freq_lock);
+#endif
+}
+
+static void unaccount_freq_event(void)
+{
+	if (tick_nohz_full_enabled())
+		unaccount_freq_event_nohz();
+	else
+		atomic_dec(&nr_freq_events);
+}
+
+static void unaccount_event(struct perf_event *event)
+{
+	bool dec = false;
+
+	if (event->parent)
+		return;
+
+	if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
+		dec = true;
+	if (event->attr.mmap || event->attr.mmap_data)
+		atomic_dec(&nr_mmap_events);
+	if (event->attr.build_id)
+		atomic_dec(&nr_build_id_events);
+	if (event->attr.comm)
+		atomic_dec(&nr_comm_events);
+	if (event->attr.namespaces)
+		atomic_dec(&nr_namespaces_events);
+	if (event->attr.cgroup)
+		atomic_dec(&nr_cgroup_events);
+	if (event->attr.task)
+		atomic_dec(&nr_task_events);
+	if (event->attr.freq)
+		unaccount_freq_event();
+	if (event->attr.context_switch) {
+		dec = true;
+		atomic_dec(&nr_switch_events);
+	}
+	if (is_cgroup_event(event))
+		dec = true;
+	if (has_branch_stack(event))
+		dec = true;
+	if (event->attr.ksymbol)
+		atomic_dec(&nr_ksymbol_events);
+	if (event->attr.bpf_event)
+		atomic_dec(&nr_bpf_events);
+	if (event->attr.text_poke)
+		atomic_dec(&nr_text_poke_events);
+
+	if (dec) {
+		if (!atomic_add_unless(&perf_sched_count, -1, 1))
+			schedule_delayed_work(&perf_sched_work, HZ);
+	}
+
+	unaccount_event_cpu(event, event->cpu);
+
+	unaccount_pmu_sb_event(event);
+}
+
+static void perf_sched_delayed(struct work_struct *work)
+{
+	mutex_lock(&perf_sched_mutex);
+	if (atomic_dec_and_test(&perf_sched_count))
+		static_branch_disable(&perf_sched_events);
+	mutex_unlock(&perf_sched_mutex);
+}
+
+/*
+ * The following implement mutual exclusion of events on "exclusive" pmus
+ * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
+ * at a time, so we disallow creating events that might conflict, namely:
+ *
+ *  1) cpu-wide events in the presence of per-task events,
+ *  2) per-task events in the presence of cpu-wide events,
+ *  3) two matching events on the same context.
+ *
+ * The former two cases are handled in the allocation path (perf_event_alloc(),
+ * _free_event()), the latter -- before the first perf_install_in_context().
+ */
+static int exclusive_event_init(struct perf_event *event)
+{
+	struct pmu *pmu = event->pmu;
+
+	if (!is_exclusive_pmu(pmu))
+		return 0;
+
+	/*
+	 * Prevent co-existence of per-task and cpu-wide events on the
+	 * same exclusive pmu.
+	 *
+	 * Negative pmu::exclusive_cnt means there are cpu-wide
+	 * events on this "exclusive" pmu, positive means there are
+	 * per-task events.
+	 *
+	 * Since this is called in perf_event_alloc() path, event::ctx
+	 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
+	 * to mean "per-task event", because unlike other attach states it
+	 * never gets cleared.
+	 */
+	if (event->attach_state & PERF_ATTACH_TASK) {
+		if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
+			return -EBUSY;
+	} else {
+		if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
+			return -EBUSY;
+	}
+
+	return 0;
+}
+
+static void exclusive_event_destroy(struct perf_event *event)
+{
+	struct pmu *pmu = event->pmu;
+
+	if (!is_exclusive_pmu(pmu))
+		return;
+
+	/* see comment in exclusive_event_init() */
+	if (event->attach_state & PERF_ATTACH_TASK)
+		atomic_dec(&pmu->exclusive_cnt);
+	else
+		atomic_inc(&pmu->exclusive_cnt);
+}
+
+static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
+{
+	if ((e1->pmu == e2->pmu) &&
+	    (e1->cpu == e2->cpu ||
+	     e1->cpu == -1 ||
+	     e2->cpu == -1))
+		return true;
+	return false;
+}
+
+static bool exclusive_event_installable(struct perf_event *event,
+					struct perf_event_context *ctx)
+{
+	struct perf_event *iter_event;
+	struct pmu *pmu = event->pmu;
+
+	lockdep_assert_held(&ctx->mutex);
+
+	if (!is_exclusive_pmu(pmu))
+		return true;
+
+	list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
+		if (exclusive_event_match(iter_event, event))
+			return false;
+	}
+
+	return true;
+}
+
+static void perf_addr_filters_splice(struct perf_event *event,
+				       struct list_head *head);
+
+static void _free_event(struct perf_event *event)
+{
+	irq_work_sync(&event->pending_irq);
+
+	unaccount_event(event);
+
+	security_perf_event_free(event);
+
+	if (event->rb) {
+		/*
+		 * Can happen when we close an event with re-directed output.
+		 *
+		 * Since we have a 0 refcount, perf_mmap_close() will skip
+		 * over us; possibly making our ring_buffer_put() the last.
+		 */
+		mutex_lock(&event->mmap_mutex);
+		ring_buffer_attach(event, NULL);
+		mutex_unlock(&event->mmap_mutex);
+	}
+
+	if (is_cgroup_event(event))
+		perf_detach_cgroup(event);
+
+	if (!event->parent) {
+		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
+			put_callchain_buffers();
+	}
+
+	perf_event_free_bpf_prog(event);
+	perf_addr_filters_splice(event, NULL);
+	kfree(event->addr_filter_ranges);
+
+	if (event->destroy)
+		event->destroy(event);
+
+	/*
+	 * Must be after ->destroy(), due to uprobe_perf_close() using
+	 * hw.target.
+	 */
+	if (event->hw.target)
+		put_task_struct(event->hw.target);
+
+	/*
+	 * perf_event_free_task() relies on put_ctx() being 'last', in particular
+	 * all task references must be cleaned up.
+	 */
+	if (event->ctx)
+		put_ctx(event->ctx);
+
+	exclusive_event_destroy(event);
+	module_put(event->pmu->module);
+
+	call_rcu(&event->rcu_head, free_event_rcu);
+}
+
+/*
+ * Used to free events which have a known refcount of 1, such as in error paths
+ * where the event isn't exposed yet and inherited events.
+ */
+static void free_event(struct perf_event *event)
+{
+	if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
+				"unexpected event refcount: %ld; ptr=%p\n",
+				atomic_long_read(&event->refcount), event)) {
+		/* leak to avoid use-after-free */
+		return;
+	}
+
+	_free_event(event);
+}
+
+/*
+ * Remove user event from the owner task.
+ */
+static void perf_remove_from_owner(struct perf_event *event)
+{
+	struct task_struct *owner;
+
+	rcu_read_lock();
+	/*
+	 * Matches the smp_store_release() in perf_event_exit_task(). If we
+	 * observe !owner it means the list deletion is complete and we can
+	 * indeed free this event, otherwise we need to serialize on
+	 * owner->perf_event_mutex.
+	 */
+	owner = READ_ONCE(event->owner);
+	if (owner) {
+		/*
+		 * Since delayed_put_task_struct() also drops the last
+		 * task reference we can safely take a new reference
+		 * while holding the rcu_read_lock().
+		 */
+		get_task_struct(owner);
+	}
+	rcu_read_unlock();
+
+	if (owner) {
+		/*
+		 * If we're here through perf_event_exit_task() we're already
+		 * holding ctx->mutex which would be an inversion wrt. the
+		 * normal lock order.
+		 *
+		 * However we can safely take this lock because its the child
+		 * ctx->mutex.
+		 */
+		mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
+
+		/*
+		 * We have to re-check the event->owner field, if it is cleared
+		 * we raced with perf_event_exit_task(), acquiring the mutex
+		 * ensured they're done, and we can proceed with freeing the
+		 * event.
+		 */
+		if (event->owner) {
+			list_del_init(&event->owner_entry);
+			smp_store_release(&event->owner, NULL);
+		}
+		mutex_unlock(&owner->perf_event_mutex);
+		put_task_struct(owner);
+	}
+}
+
+static void put_event(struct perf_event *event)
+{
+	if (!atomic_long_dec_and_test(&event->refcount))
+		return;
+
+	_free_event(event);
+}
+
+/*
+ * Kill an event dead; while event:refcount will preserve the event
+ * object, it will not preserve its functionality. Once the last 'user'
+ * gives up the object, we'll destroy the thing.
+ */
+int perf_event_release_kernel(struct perf_event *event)
+{
+	struct perf_event_context *ctx = event->ctx;
+	struct perf_event *child, *tmp;
+	LIST_HEAD(free_list);
+
+	/*
+	 * If we got here through err_file: fput(event_file); we will not have
+	 * attached to a context yet.
+	 */
+	if (!ctx) {
+		WARN_ON_ONCE(event->attach_state &
+				(PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
+		goto no_ctx;
+	}
+
+	if (!is_kernel_event(event))
+		perf_remove_from_owner(event);
+
+	ctx = perf_event_ctx_lock(event);
+	WARN_ON_ONCE(ctx->parent_ctx);
+
+	/*
+	 * Mark this event as STATE_DEAD, there is no external reference to it
+	 * anymore.
+	 *
+	 * Anybody acquiring event->child_mutex after the below loop _must_
+	 * also see this, most importantly inherit_event() which will avoid
+	 * placing more children on the list.
+	 *
+	 * Thus this guarantees that we will in fact observe and kill _ALL_
+	 * child events.
+	 */
+	perf_remove_from_context(event, DETACH_GROUP|DETACH_DEAD);
+
+	perf_event_ctx_unlock(event, ctx);
+
+again:
+	mutex_lock(&event->child_mutex);
+	list_for_each_entry(child, &event->child_list, child_list) {
+
+		/*
+		 * Cannot change, child events are not migrated, see the
+		 * comment with perf_event_ctx_lock_nested().
+		 */
+		ctx = READ_ONCE(child->ctx);
+		/*
+		 * Since child_mutex nests inside ctx::mutex, we must jump
+		 * through hoops. We start by grabbing a reference on the ctx.
+		 *
+		 * Since the event cannot get freed while we hold the
+		 * child_mutex, the context must also exist and have a !0
+		 * reference count.
+		 */
+		get_ctx(ctx);
+
+		/*
+		 * Now that we have a ctx ref, we can drop child_mutex, and
+		 * acquire ctx::mutex without fear of it going away. Then we
+		 * can re-acquire child_mutex.
+		 */
+		mutex_unlock(&event->child_mutex);
+		mutex_lock(&ctx->mutex);
+		mutex_lock(&event->child_mutex);
+
+		/*
+		 * Now that we hold ctx::mutex and child_mutex, revalidate our
+		 * state, if child is still the first entry, it didn't get freed
+		 * and we can continue doing so.
+		 */
+		tmp = list_first_entry_or_null(&event->child_list,
+					       struct perf_event, child_list);
+		if (tmp == child) {
+			perf_remove_from_context(child, DETACH_GROUP);
+			list_move(&child->child_list, &free_list);
+			/*
+			 * This matches the refcount bump in inherit_event();
+			 * this can't be the last reference.
+			 */
+			put_event(event);
+		}
+
+		mutex_unlock(&event->child_mutex);
+		mutex_unlock(&ctx->mutex);
+		put_ctx(ctx);
+		goto again;
+	}
+	mutex_unlock(&event->child_mutex);
+
+	list_for_each_entry_safe(child, tmp, &free_list, child_list) {
+		void *var = &child->ctx->refcount;
+
+		list_del(&child->child_list);
+		free_event(child);
+
+		/*
+		 * Wake any perf_event_free_task() waiting for this event to be
+		 * freed.
+		 */
+		smp_mb(); /* pairs with wait_var_event() */
+		wake_up_var(var);
+	}
+
+no_ctx:
+	put_event(event); /* Must be the 'last' reference */
+	return 0;
+}
+EXPORT_SYMBOL_GPL(perf_event_release_kernel);
+
+/*
+ * Called when the last reference to the file is gone.
+ */
+static int perf_release(struct inode *inode, struct file *file)
+{
+	perf_event_release_kernel(file->private_data);
+	return 0;
+}
+
+static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
+{
+	struct perf_event *child;
+	u64 total = 0;
+
+	*enabled = 0;
+	*running = 0;
+
+	mutex_lock(&event->child_mutex);
+
+	(void)perf_event_read(event, false);
+	total += perf_event_count(event);
+
+	*enabled += event->total_time_enabled +
+			atomic64_read(&event->child_total_time_enabled);
+	*running += event->total_time_running +
+			atomic64_read(&event->child_total_time_running);
+
+	list_for_each_entry(child, &event->child_list, child_list) {
+		(void)perf_event_read(child, false);
+		total += perf_event_count(child);
+		*enabled += child->total_time_enabled;
+		*running += child->total_time_running;
+	}
+	mutex_unlock(&event->child_mutex);
+
+	return total;
+}
+
+u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
+{
+	struct perf_event_context *ctx;
+	u64 count;
+
+	ctx = perf_event_ctx_lock(event);
+	count = __perf_event_read_value(event, enabled, running);
+	perf_event_ctx_unlock(event, ctx);
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(perf_event_read_value);
+
+static int __perf_read_group_add(struct perf_event *leader,
+					u64 read_format, u64 *values)
+{
+	struct perf_event_context *ctx = leader->ctx;
+	struct perf_event *sub, *parent;
+	unsigned long flags;
+	int n = 1; /* skip @nr */
+	int ret;
+
+	ret = perf_event_read(leader, true);
+	if (ret)
+		return ret;
+
+	raw_spin_lock_irqsave(&ctx->lock, flags);
+	/*
+	 * Verify the grouping between the parent and child (inherited)
+	 * events is still in tact.
+	 *
+	 * Specifically:
+	 *  - leader->ctx->lock pins leader->sibling_list
+	 *  - parent->child_mutex pins parent->child_list
+	 *  - parent->ctx->mutex pins parent->sibling_list
+	 *
+	 * Because parent->ctx != leader->ctx (and child_list nests inside
+	 * ctx->mutex), group destruction is not atomic between children, also
+	 * see perf_event_release_kernel(). Additionally, parent can grow the
+	 * group.
+	 *
+	 * Therefore it is possible to have parent and child groups in a
+	 * different configuration and summing over such a beast makes no sense
+	 * what so ever.
+	 *
+	 * Reject this.
+	 */
+	parent = leader->parent;
+	if (parent &&
+	    (parent->group_generation != leader->group_generation ||
+	     parent->nr_siblings != leader->nr_siblings)) {
+		ret = -ECHILD;
+		goto unlock;
+	}
+
+	/*
+	 * Since we co-schedule groups, {enabled,running} times of siblings
+	 * will be identical to those of the leader, so we only publish one
+	 * set.
+	 */
+	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
+		values[n++] += leader->total_time_enabled +
+			atomic64_read(&leader->child_total_time_enabled);
+	}
+
+	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
+		values[n++] += leader->total_time_running +
+			atomic64_read(&leader->child_total_time_running);
+	}
+
+	/*
+	 * Write {count,id} tuples for every sibling.
+	 */
+	values[n++] += perf_event_count(leader);
+	if (read_format & PERF_FORMAT_ID)
+		values[n++] = primary_event_id(leader);
+	if (read_format & PERF_FORMAT_LOST)
+		values[n++] = atomic64_read(&leader->lost_samples);
+
+	for_each_sibling_event(sub, leader) {
+		values[n++] += perf_event_count(sub);
+		if (read_format & PERF_FORMAT_ID)
+			values[n++] = primary_event_id(sub);
+		if (read_format & PERF_FORMAT_LOST)
+			values[n++] = atomic64_read(&sub->lost_samples);
+	}
+
+unlock:
+	raw_spin_unlock_irqrestore(&ctx->lock, flags);
+	return ret;
+}
+
+static int perf_read_group(struct perf_event *event,
+				   u64 read_format, char __user *buf)
+{
+	struct perf_event *leader = event->group_leader, *child;
+	struct perf_event_context *ctx = leader->ctx;
+	int ret;
+	u64 *values;
+
+	lockdep_assert_held(&ctx->mutex);
+
+	values = kzalloc(event->read_size, GFP_KERNEL);
+	if (!values)
+		return -ENOMEM;
+
+	values[0] = 1 + leader->nr_siblings;
+
+	mutex_lock(&leader->child_mutex);
+
+	ret = __perf_read_group_add(leader, read_format, values);
+	if (ret)
+		goto unlock;
+
+	list_for_each_entry(child, &leader->child_list, child_list) {
+		ret = __perf_read_group_add(child, read_format, values);
+		if (ret)
+			goto unlock;
+	}
+
+	mutex_unlock(&leader->child_mutex);
+
+	ret = event->read_size;
+	if (copy_to_user(buf, values, event->read_size))
+		ret = -EFAULT;
+	goto out;
+
+unlock:
+	mutex_unlock(&leader->child_mutex);
+out:
+	kfree(values);
+	return ret;
+}
+
+static int perf_read_one(struct perf_event *event,
+				 u64 read_format, char __user *buf)
+{
+	u64 enabled, running;
+	u64 values[5];
+	int n = 0;
+
+	values[n++] = __perf_event_read_value(event, &enabled, &running);
+	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+		values[n++] = enabled;
+	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+		values[n++] = running;
+	if (read_format & PERF_FORMAT_ID)
+		values[n++] = primary_event_id(event);
+	if (read_format & PERF_FORMAT_LOST)
+		values[n++] = atomic64_read(&event->lost_samples);
+
+	if (copy_to_user(buf, values, n * sizeof(u64)))
+		return -EFAULT;
+
+	return n * sizeof(u64);
+}
+
+static bool is_event_hup(struct perf_event *event)
+{
+	bool no_children;
+
+	if (event->state > PERF_EVENT_STATE_EXIT)
+		return false;
+
+	mutex_lock(&event->child_mutex);
+	no_children = list_empty(&event->child_list);
+	mutex_unlock(&event->child_mutex);
+	return no_children;
+}
+
+/*
+ * Read the performance event - simple non blocking version for now
+ */
+static ssize_t
+__perf_read(struct perf_event *event, char __user *buf, size_t count)
+{
+	u64 read_format = event->attr.read_format;
+	int ret;
+
+	/*
+	 * Return end-of-file for a read on an event that is in
+	 * error state (i.e. because it was pinned but it couldn't be
+	 * scheduled on to the CPU at some point).
+	 */
+	if (event->state == PERF_EVENT_STATE_ERROR)
+		return 0;
+
+	if (count < event->read_size)
+		return -ENOSPC;
+
+	WARN_ON_ONCE(event->ctx->parent_ctx);
+	if (read_format & PERF_FORMAT_GROUP)
+		ret = perf_read_group(event, read_format, buf);
+	else
+		ret = perf_read_one(event, read_format, buf);
+
+	return ret;
+}
+
+static ssize_t
+perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+	struct perf_event *event = file->private_data;
+	struct perf_event_context *ctx;
+	int ret;
+
+	ret = security_perf_event_read(event);
+	if (ret)
+		return ret;
+
+	ctx = perf_event_ctx_lock(event);
+	ret = __perf_read(event, buf, count);
+	perf_event_ctx_unlock(event, ctx);
+
+	return ret;
+}
+
+static __poll_t perf_poll(struct file *file, poll_table *wait)
+{
+	struct perf_event *event = file->private_data;
+	struct perf_buffer *rb;
+	__poll_t events = EPOLLHUP;
+
+	poll_wait(file, &event->waitq, wait);
+
+	if (is_event_hup(event))
+		return events;
+
+	/*
+	 * Pin the event->rb by taking event->mmap_mutex; otherwise
+	 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
+	 */
+	mutex_lock(&event->mmap_mutex);
+	rb = event->rb;
+	if (rb)
+		events = atomic_xchg(&rb->poll, 0);
+	mutex_unlock(&event->mmap_mutex);
+	return events;
+}
+
+static void _perf_event_reset(struct perf_event *event)
+{
+	(void)perf_event_read(event, false);
+	local64_set(&event->count, 0);
+	perf_event_update_userpage(event);
+}
+
+/* Assume it's not an event with inherit set. */
+u64 perf_event_pause(struct perf_event *event, bool reset)
+{
+	struct perf_event_context *ctx;
+	u64 count;
+
+	ctx = perf_event_ctx_lock(event);
+	WARN_ON_ONCE(event->attr.inherit);
+	_perf_event_disable(event);
+	count = local64_read(&event->count);
+	if (reset)
+		local64_set(&event->count, 0);
+	perf_event_ctx_unlock(event, ctx);
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(perf_event_pause);
+
+/*
+ * Holding the top-level event's child_mutex means that any
+ * descendant process that has inherited this event will block
+ * in perf_event_exit_event() if it goes to exit, thus satisfying the
+ * task existence requirements of perf_event_enable/disable.
+ */
+static void perf_event_for_each_child(struct perf_event *event,
+					void (*func)(struct perf_event *))
+{
+	struct perf_event *child;
+
+	WARN_ON_ONCE(event->ctx->parent_ctx);
+
+	mutex_lock(&event->child_mutex);
+	func(event);
+	list_for_each_entry(child, &event->child_list, child_list)
+		func(child);
+	mutex_unlock(&event->child_mutex);
+}
+
+static void perf_event_for_each(struct perf_event *event,
+				  void (*func)(struct perf_event *))
+{
+	struct perf_event_context *ctx = event->ctx;
+	struct perf_event *sibling;
+
+	lockdep_assert_held(&ctx->mutex);
+
+	event = event->group_leader;
+
+	perf_event_for_each_child(event, func);
+	for_each_sibling_event(sibling, event)
+		perf_event_for_each_child(sibling, func);
+}
+
+static void __perf_event_period(struct perf_event *event,
+				struct perf_cpu_context *cpuctx,
+				struct perf_event_context *ctx,
+				void *info)
+{
+	u64 value = *((u64 *)info);
+	bool active;
+
+	if (event->attr.freq) {
+		event->attr.sample_freq = value;
+	} else {
+		event->attr.sample_period = value;
+		event->hw.sample_period = value;
+	}
+
+	active = (event->state == PERF_EVENT_STATE_ACTIVE);
+	if (active) {
+		perf_pmu_disable(ctx->pmu);
+		/*
+		 * We could be throttled; unthrottle now to avoid the tick
+		 * trying to unthrottle while we already re-started the event.
+		 */
+		if (event->hw.interrupts == MAX_INTERRUPTS) {
+			event->hw.interrupts = 0;
+			perf_log_throttle(event, 1);
+		}
+		event->pmu->stop(event, PERF_EF_UPDATE);
+	}
+
+	local64_set(&event->hw.period_left, 0);
+
+	if (active) {
+		event->pmu->start(event, PERF_EF_RELOAD);
+		perf_pmu_enable(ctx->pmu);
+	}
+}
+
+static int perf_event_check_period(struct perf_event *event, u64 value)
+{
+	return event->pmu->check_period(event, value);
+}
+
+static int _perf_event_period(struct perf_event *event, u64 value)
+{
+	if (!is_sampling_event(event))
+		return -EINVAL;
+
+	if (!value)
+		return -EINVAL;
+
+	if (event->attr.freq && value > sysctl_perf_event_sample_rate)
+		return -EINVAL;
+
+	if (perf_event_check_period(event, value))
+		return -EINVAL;
+
+	if (!event->attr.freq && (value & (1ULL << 63)))
+		return -EINVAL;
+
+	event_function_call(event, __perf_event_period, &value);
+
+	return 0;
+}
+
+int perf_event_period(struct perf_event *event, u64 value)
+{
+	struct perf_event_context *ctx;
+	int ret;
+
+	ctx = perf_event_ctx_lock(event);
+	ret = _perf_event_period(event, value);
+	perf_event_ctx_unlock(event, ctx);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(perf_event_period);
+
+static const struct file_operations perf_fops;
+
+static inline int perf_fget_light(int fd, struct fd *p)
+{
+	struct fd f = fdget(fd);
+	if (!f.file)
+		return -EBADF;
+
+	if (f.file->f_op != &perf_fops) {
+		fdput(f);
+		return -EBADF;
+	}
+	*p = f;
+	return 0;
+}
+
+static int perf_event_set_output(struct perf_event *event,
+				 struct perf_event *output_event);
+static int perf_event_set_filter(struct perf_event *event, void __user *arg);
+static int perf_copy_attr(struct perf_event_attr __user *uattr,
+			  struct perf_event_attr *attr);
+
+static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
+{
+	void (*func)(struct perf_event *);
+	u32 flags = arg;
+
+	switch (cmd) {
+	case PERF_EVENT_IOC_ENABLE:
+		func = _perf_event_enable;
+		break;
+	case PERF_EVENT_IOC_DISABLE:
+		func = _perf_event_disable;
+		break;
+	case PERF_EVENT_IOC_RESET:
+		func = _perf_event_reset;
+		break;
+
+	case PERF_EVENT_IOC_REFRESH:
+		return _perf_event_refresh(event, arg);
+
+	case PERF_EVENT_IOC_PERIOD:
+	{
+		u64 value;
+
+		if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
+			return -EFAULT;
+
+		return _perf_event_period(event, value);
+	}
+	case PERF_EVENT_IOC_ID:
+	{
+		u64 id = primary_event_id(event);
+
+		if (copy_to_user((void __user *)arg, &id, sizeof(id)))
+			return -EFAULT;
+		return 0;
+	}
+
+	case PERF_EVENT_IOC_SET_OUTPUT:
+	{
+		int ret;
+		if (arg != -1) {
+			struct perf_event *output_event;
+			struct fd output;
+			ret = perf_fget_light(arg, &output);
+			if (ret)
+				return ret;
+			output_event = output.file->private_data;
+			ret = perf_event_set_output(event, output_event);
+			fdput(output);
+		} else {
+			ret = perf_event_set_output(event, NULL);
+		}
+		return ret;
+	}
+
+	case PERF_EVENT_IOC_SET_FILTER:
+		return perf_event_set_filter(event, (void __user *)arg);
+
+	case PERF_EVENT_IOC_SET_BPF:
+	{
+		struct bpf_prog *prog;
+		int err;
+
+		prog = bpf_prog_get(arg);
+		if (IS_ERR(prog))
+			return PTR_ERR(prog);
+
+		err = perf_event_set_bpf_prog(event, prog, 0);
+		if (err) {
+			bpf_prog_put(prog);
+			return err;
+		}
+
+		return 0;
+	}
+
+	case PERF_EVENT_IOC_PAUSE_OUTPUT: {
+		struct perf_buffer *rb;
+
+		rcu_read_lock();
+		rb = rcu_dereference(event->rb);
+		if (!rb || !rb->nr_pages) {
+			rcu_read_unlock();
+			return -EINVAL;
+		}
+		rb_toggle_paused(rb, !!arg);
+		rcu_read_unlock();
+		return 0;
+	}
+
+	case PERF_EVENT_IOC_QUERY_BPF:
+		return perf_event_query_prog_array(event, (void __user *)arg);
+
+	case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
+		struct perf_event_attr new_attr;
+		int err = perf_copy_attr((struct perf_event_attr __user *)arg,
+					 &new_attr);
+
+		if (err)
+			return err;
+
+		return perf_event_modify_attr(event,  &new_attr);
+	}
+	default:
+		return -ENOTTY;
+	}
+
+	if (flags & PERF_IOC_FLAG_GROUP)
+		perf_event_for_each(event, func);
+	else
+		perf_event_for_each_child(event, func);
+
+	return 0;
+}
+
+static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct perf_event *event = file->private_data;
+	struct perf_event_context *ctx;
+	long ret;
+
+	/* Treat ioctl like writes as it is likely a mutating operation. */
+	ret = security_perf_event_write(event);
+	if (ret)
+		return ret;
+
+	ctx = perf_event_ctx_lock(event);
+	ret = _perf_ioctl(event, cmd, arg);
+	perf_event_ctx_unlock(event, ctx);
+
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT
+static long perf_compat_ioctl(struct file *file, unsigned int cmd,
+				unsigned long arg)
+{
+	switch (_IOC_NR(cmd)) {
+	case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
+	case _IOC_NR(PERF_EVENT_IOC_ID):
+	case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
+	case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
+		/* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
+		if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
+			cmd &= ~IOCSIZE_MASK;
+			cmd |= sizeof(void *) << IOCSIZE_SHIFT;
+		}
+		break;
+	}
+	return perf_ioctl(file, cmd, arg);
+}
+#else
+# define perf_compat_ioctl NULL
+#endif
+
+int perf_event_task_enable(void)
+{
+	struct perf_event_context *ctx;
+	struct perf_event *event;
+
+	mutex_lock(&current->perf_event_mutex);
+	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
+		ctx = perf_event_ctx_lock(event);
+		perf_event_for_each_child(event, _perf_event_enable);
+		perf_event_ctx_unlock(event, ctx);
+	}
+	mutex_unlock(&current->perf_event_mutex);
+
+	return 0;
+}
+
+int perf_event_task_disable(void)
+{
+	struct perf_event_context *ctx;
+	struct perf_event *event;
+
+	mutex_lock(&current->perf_event_mutex);
+	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
+		ctx = perf_event_ctx_lock(event);
+		perf_event_for_each_child(event, _perf_event_disable);
+		perf_event_ctx_unlock(event, ctx);
+	}
+	mutex_unlock(&current->perf_event_mutex);
+
+	return 0;
+}
+
+static int perf_event_index(struct perf_event *event)
+{
+	if (event->hw.state & PERF_HES_STOPPED)
+		return 0;
+
+	if (event->state != PERF_EVENT_STATE_ACTIVE)
+		return 0;
+
+	return event->pmu->event_idx(event);
+}
+
+static void perf_event_init_userpage(struct perf_event *event)
+{
+	struct perf_event_mmap_page *userpg;
+	struct perf_buffer *rb;
+
+	rcu_read_lock();
+	rb = rcu_dereference(event->rb);
+	if (!rb)
+		goto unlock;
+
+	userpg = rb->user_page;
+
+	/* Allow new userspace to detect that bit 0 is deprecated */
+	userpg->cap_bit0_is_deprecated = 1;
+	userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
+	userpg->data_offset = PAGE_SIZE;
+	userpg->data_size = perf_data_size(rb);
+
+unlock:
+	rcu_read_unlock();
+}
+
+void __weak arch_perf_update_userpage(
+	struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
+{
+}
+
+/*
+ * Callers need to ensure there can be no nesting of this function, otherwise
+ * the seqlock logic goes bad. We can not serialize this because the arch
+ * code calls this from NMI context.
+ */
+void perf_event_update_userpage(struct perf_event *event)
+{
+	struct perf_event_mmap_page *userpg;
+	struct perf_buffer *rb;
+	u64 enabled, running, now;
+
+	rcu_read_lock();
+	rb = rcu_dereference(event->rb);
+	if (!rb)
+		goto unlock;
+
+	/*
+	 * compute total_time_enabled, total_time_running
+	 * based on snapshot values taken when the event
+	 * was last scheduled in.
+	 *
+	 * we cannot simply called update_context_time()
+	 * because of locking issue as we can be called in
+	 * NMI context
+	 */
+	calc_timer_values(event, &now, &enabled, &running);
+
+	userpg = rb->user_page;
+	/*
+	 * Disable preemption to guarantee consistent time stamps are stored to
+	 * the user page.
+	 */
+	preempt_disable();
+	++userpg->lock;
+	barrier();
+	userpg->index = perf_event_index(event);
+	userpg->offset = perf_event_count(event);
+	if (userpg->index)
+		userpg->offset -= local64_read(&event->hw.prev_count);
+
+	userpg->time_enabled = enabled +
+			atomic64_read(&event->child_total_time_enabled);
+
+	userpg->time_running = running +
+			atomic64_read(&event->child_total_time_running);
+
+	arch_perf_update_userpage(event, userpg, now);
+
+	barrier();
+	++userpg->lock;
+	preempt_enable();
+unlock:
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(perf_event_update_userpage);
+
+static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
+{
+	struct perf_event *event = vmf->vma->vm_file->private_data;
+	struct perf_buffer *rb;
+	vm_fault_t ret = VM_FAULT_SIGBUS;
+
+	if (vmf->flags & FAULT_FLAG_MKWRITE) {
+		if (vmf->pgoff == 0)
+			ret = 0;
+		return ret;
+	}
+
+	rcu_read_lock();
+	rb = rcu_dereference(event->rb);
+	if (!rb)
+		goto unlock;
+
+	if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
+		goto unlock;
+
+	vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
+	if (!vmf->page)
+		goto unlock;
+
+	get_page(vmf->page);
+	vmf->page->mapping = vmf->vma->vm_file->f_mapping;
+	vmf->page->index   = vmf->pgoff;
+
+	ret = 0;
+unlock:
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static void ring_buffer_attach(struct perf_event *event,
+			       struct perf_buffer *rb)
+{
+	struct perf_buffer *old_rb = NULL;
+	unsigned long flags;
+
+	WARN_ON_ONCE(event->parent);
+
+	if (event->rb) {
+		/*
+		 * Should be impossible, we set this when removing
+		 * event->rb_entry and wait/clear when adding event->rb_entry.
+		 */
+		WARN_ON_ONCE(event->rcu_pending);
+
+		old_rb = event->rb;
+		spin_lock_irqsave(&old_rb->event_lock, flags);
+		list_del_rcu(&event->rb_entry);
+		spin_unlock_irqrestore(&old_rb->event_lock, flags);
+
+		event->rcu_batches = get_state_synchronize_rcu();
+		event->rcu_pending = 1;
+	}
+
+	if (rb) {
+		if (event->rcu_pending) {
+			cond_synchronize_rcu(event->rcu_batches);
+			event->rcu_pending = 0;
+		}
+
+		spin_lock_irqsave(&rb->event_lock, flags);
+		list_add_rcu(&event->rb_entry, &rb->event_list);
+		spin_unlock_irqrestore(&rb->event_lock, flags);
+	}
+
+	/*
+	 * Avoid racing with perf_mmap_close(AUX): stop the event
+	 * before swizzling the event::rb pointer; if it's getting
+	 * unmapped, its aux_mmap_count will be 0 and it won't
+	 * restart. See the comment in __perf_pmu_output_stop().
+	 *
+	 * Data will inevitably be lost when set_output is done in
+	 * mid-air, but then again, whoever does it like this is
+	 * not in for the data anyway.
+	 */
+	if (has_aux(event))
+		perf_event_stop(event, 0);
+
+	rcu_assign_pointer(event->rb, rb);
+
+	if (old_rb) {
+		ring_buffer_put(old_rb);
+		/*
+		 * Since we detached before setting the new rb, so that we
+		 * could attach the new rb, we could have missed a wakeup.
+		 * Provide it now.
+		 */
+		wake_up_all(&event->waitq);
+	}
+}
+
+static void ring_buffer_wakeup(struct perf_event *event)
+{
+	struct perf_buffer *rb;
+
+	if (event->parent)
+		event = event->parent;
+
+	rcu_read_lock();
+	rb = rcu_dereference(event->rb);
+	if (rb) {
+		list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
+			wake_up_all(&event->waitq);
+	}
+	rcu_read_unlock();
+}
+
+struct perf_buffer *ring_buffer_get(struct perf_event *event)
+{
+	struct perf_buffer *rb;
+
+	if (event->parent)
+		event = event->parent;
+
+	rcu_read_lock();
+	rb = rcu_dereference(event->rb);
+	if (rb) {
+		if (!refcount_inc_not_zero(&rb->refcount))
+			rb = NULL;
+	}
+	rcu_read_unlock();
+
+	return rb;
+}
+
+void ring_buffer_put(struct perf_buffer *rb)
+{
+	if (!refcount_dec_and_test(&rb->refcount))
+		return;
+
+	WARN_ON_ONCE(!list_empty(&rb->event_list));
+
+	call_rcu(&rb->rcu_head, rb_free_rcu);
+}
+
+static void perf_mmap_open(struct vm_area_struct *vma)
+{
+	struct perf_event *event = vma->vm_file->private_data;
+
+	atomic_inc(&event->mmap_count);
+	atomic_inc(&event->rb->mmap_count);
+
+	if (vma->vm_pgoff)
+		atomic_inc(&event->rb->aux_mmap_count);
+
+	if (event->pmu->event_mapped)
+		event->pmu->event_mapped(event, vma->vm_mm);
+}
+
+static void perf_pmu_output_stop(struct perf_event *event);
+
+/*
+ * A buffer can be mmap()ed multiple times; either directly through the same
+ * event, or through other events by use of perf_event_set_output().
+ *
+ * In order to undo the VM accounting done by perf_mmap() we need to destroy
+ * the buffer here, where we still have a VM context. This means we need
+ * to detach all events redirecting to us.
+ */
+static void perf_mmap_close(struct vm_area_struct *vma)
+{
+	struct perf_event *event = vma->vm_file->private_data;
+	struct perf_buffer *rb = ring_buffer_get(event);
+	struct user_struct *mmap_user = rb->mmap_user;
+	int mmap_locked = rb->mmap_locked;
+	unsigned long size = perf_data_size(rb);
+	bool detach_rest = false;
+
+	if (event->pmu->event_unmapped)
+		event->pmu->event_unmapped(event, vma->vm_mm);
+
+	/*
+	 * rb->aux_mmap_count will always drop before rb->mmap_count and
+	 * event->mmap_count, so it is ok to use event->mmap_mutex to
+	 * serialize with perf_mmap here.
+	 */
+	if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
+	    atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
+		/*
+		 * Stop all AUX events that are writing to this buffer,
+		 * so that we can free its AUX pages and corresponding PMU
+		 * data. Note that after rb::aux_mmap_count dropped to zero,
+		 * they won't start any more (see perf_aux_output_begin()).
+		 */
+		perf_pmu_output_stop(event);
+
+		/* now it's safe to free the pages */
+		atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
+		atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
+
+		/* this has to be the last one */
+		rb_free_aux(rb);
+		WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
+
+		mutex_unlock(&event->mmap_mutex);
+	}
+
+	if (atomic_dec_and_test(&rb->mmap_count))
+		detach_rest = true;
+
+	if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
+		goto out_put;
+
+	ring_buffer_attach(event, NULL);
+	mutex_unlock(&event->mmap_mutex);
+
+	/* If there's still other mmap()s of this buffer, we're done. */
+	if (!detach_rest)
+		goto out_put;
+
+	/*
+	 * No other mmap()s, detach from all other events that might redirect
+	 * into the now unreachable buffer. Somewhat complicated by the
+	 * fact that rb::event_lock otherwise nests inside mmap_mutex.
+	 */
+again:
+	rcu_read_lock();
+	list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
+		if (!atomic_long_inc_not_zero(&event->refcount)) {
+			/*
+			 * This event is en-route to free_event() which will
+			 * detach it and remove it from the list.
+			 */
+			continue;
+		}
+		rcu_read_unlock();
+
+		mutex_lock(&event->mmap_mutex);
+		/*
+		 * Check we didn't race with perf_event_set_output() which can
+		 * swizzle the rb from under us while we were waiting to
+		 * acquire mmap_mutex.
+		 *
+		 * If we find a different rb; ignore this event, a next
+		 * iteration will no longer find it on the list. We have to
+		 * still restart the iteration to make sure we're not now
+		 * iterating the wrong list.
+		 */
+		if (event->rb == rb)
+			ring_buffer_attach(event, NULL);
+
+		mutex_unlock(&event->mmap_mutex);
+		put_event(event);
+
+		/*
+		 * Restart the iteration; either we're on the wrong list or
+		 * destroyed its integrity by doing a deletion.
+		 */
+		goto again;
+	}
+	rcu_read_unlock();
+
+	/*
+	 * It could be there's still a few 0-ref events on the list; they'll
+	 * get cleaned up by free_event() -- they'll also still have their
+	 * ref on the rb and will free it whenever they are done with it.
+	 *
+	 * Aside from that, this buffer is 'fully' detached and unmapped,
+	 * undo the VM accounting.
+	 */
+
+	atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
+			&mmap_user->locked_vm);
+	atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
+	free_uid(mmap_user);
+
+out_put:
+	ring_buffer_put(rb); /* could be last */
+}
+
+static const struct vm_operations_struct perf_mmap_vmops = {
+	.open		= perf_mmap_open,
+	.close		= perf_mmap_close, /* non mergeable */
+	.fault		= perf_mmap_fault,
+	.page_mkwrite	= perf_mmap_fault,
+};
+
+static int perf_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct perf_event *event = file->private_data;
+	unsigned long user_locked, user_lock_limit;
+	struct user_struct *user = current_user();
+	struct perf_buffer *rb = NULL;
+	unsigned long locked, lock_limit;
+	unsigned long vma_size;
+	unsigned long nr_pages;
+	long user_extra = 0, extra = 0;
+	int ret = 0, flags = 0;
+
+	/*
+	 * Don't allow mmap() of inherited per-task counters. This would
+	 * create a performance issue due to all children writing to the
+	 * same rb.
+	 */
+	if (event->cpu == -1 && event->attr.inherit)
+		return -EINVAL;
+
+	if (!(vma->vm_flags & VM_SHARED))
+		return -EINVAL;
+
+	ret = security_perf_event_read(event);
+	if (ret)
+		return ret;
+
+	vma_size = vma->vm_end - vma->vm_start;
+
+	if (vma->vm_pgoff == 0) {
+		nr_pages = (vma_size / PAGE_SIZE) - 1;
+	} else {
+		/*
+		 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
+		 * mapped, all subsequent mappings should have the same size
+		 * and offset. Must be above the normal perf buffer.
+		 */
+		u64 aux_offset, aux_size;
+
+		if (!event->rb)
+			return -EINVAL;
+
+		nr_pages = vma_size / PAGE_SIZE;
+
+		mutex_lock(&event->mmap_mutex);
+		ret = -EINVAL;
+
+		rb = event->rb;
+		if (!rb)
+			goto aux_unlock;
+
+		aux_offset = READ_ONCE(rb->user_page->aux_offset);
+		aux_size = READ_ONCE(rb->user_page->aux_size);
+
+		if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
+			goto aux_unlock;
+
+		if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
+			goto aux_unlock;
+
+		/* already mapped with a different offset */
+		if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
+			goto aux_unlock;
+
+		if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
+			goto aux_unlock;
+
+		/* already mapped with a different size */
+		if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
+			goto aux_unlock;
+
+		if (!is_power_of_2(nr_pages))
+			goto aux_unlock;
+
+		if (!atomic_inc_not_zero(&rb->mmap_count))
+			goto aux_unlock;
+
+		if (rb_has_aux(rb)) {
+			atomic_inc(&rb->aux_mmap_count);
+			ret = 0;
+			goto unlock;
+		}
+
+		atomic_set(&rb->aux_mmap_count, 1);
+		user_extra = nr_pages;
+
+		goto accounting;
+	}
+
+	/*
+	 * If we have rb pages ensure they're a power-of-two number, so we
+	 * can do bitmasks instead of modulo.
+	 */
+	if (nr_pages != 0 && !is_power_of_2(nr_pages))
+		return -EINVAL;
+
+	if (vma_size != PAGE_SIZE * (1 + nr_pages))
+		return -EINVAL;
+
+	WARN_ON_ONCE(event->ctx->parent_ctx);
+again:
+	mutex_lock(&event->mmap_mutex);
+	if (event->rb) {
+		if (data_page_nr(event->rb) != nr_pages) {
+			ret = -EINVAL;
+			goto unlock;
+		}
+
+		if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
+			/*
+			 * Raced against perf_mmap_close(); remove the
+			 * event and try again.
+			 */
+			ring_buffer_attach(event, NULL);
+			mutex_unlock(&event->mmap_mutex);
+			goto again;
+		}
+
+		goto unlock;
+	}
+
+	user_extra = nr_pages + 1;
+
+accounting:
+	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
+
+	/*
+	 * Increase the limit linearly with more CPUs:
+	 */
+	user_lock_limit *= num_online_cpus();
+
+	user_locked = atomic_long_read(&user->locked_vm);
+
+	/*
+	 * sysctl_perf_event_mlock may have changed, so that
+	 *     user->locked_vm > user_lock_limit
+	 */
+	if (user_locked > user_lock_limit)
+		user_locked = user_lock_limit;
+	user_locked += user_extra;
+
+	if (user_locked > user_lock_limit) {
+		/*
+		 * charge locked_vm until it hits user_lock_limit;
+		 * charge the rest from pinned_vm
+		 */
+		extra = user_locked - user_lock_limit;
+		user_extra -= extra;
+	}
+
+	lock_limit = rlimit(RLIMIT_MEMLOCK);
+	lock_limit >>= PAGE_SHIFT;
+	locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
+
+	if ((locked > lock_limit) && perf_is_paranoid() &&
+		!capable(CAP_IPC_LOCK)) {
+		ret = -EPERM;
+		goto unlock;
+	}
+
+	WARN_ON(!rb && event->rb);
+
+	if (vma->vm_flags & VM_WRITE)
+		flags |= RING_BUFFER_WRITABLE;
+
+	if (!rb) {
+		rb = rb_alloc(nr_pages,
+			      event->attr.watermark ? event->attr.wakeup_watermark : 0,
+			      event->cpu, flags);
+
+		if (!rb) {
+			ret = -ENOMEM;
+			goto unlock;
+		}
+
+		atomic_set(&rb->mmap_count, 1);
+		rb->mmap_user = get_current_user();
+		rb->mmap_locked = extra;
+
+		ring_buffer_attach(event, rb);
+
+		perf_event_update_time(event);
+		perf_event_init_userpage(event);
+		perf_event_update_userpage(event);
+	} else {
+		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
+				   event->attr.aux_watermark, flags);
+		if (!ret)
+			rb->aux_mmap_locked = extra;
+	}
+
+unlock:
+	if (!ret) {
+		atomic_long_add(user_extra, &user->locked_vm);
+		atomic64_add(extra, &vma->vm_mm->pinned_vm);
+
+		atomic_inc(&event->mmap_count);
+	} else if (rb) {
+		atomic_dec(&rb->mmap_count);
+	}
+aux_unlock:
+	mutex_unlock(&event->mmap_mutex);
+
+	/*
+	 * Since pinned accounting is per vm we cannot allow fork() to copy our
+	 * vma.
+	 */
+	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
+	vma->vm_ops = &perf_mmap_vmops;
+
+	if (event->pmu->event_mapped)
+		event->pmu->event_mapped(event, vma->vm_mm);
+
+	return ret;
+}
+
+static int perf_fasync(int fd, struct file *filp, int on)
+{
+	struct inode *inode = file_inode(filp);
+	struct perf_event *event = filp->private_data;
+	int retval;
+
+	inode_lock(inode);
+	retval = fasync_helper(fd, filp, on, &event->fasync);
+	inode_unlock(inode);
+
+	if (retval < 0)
+		return retval;
+
+	return 0;
+}
+
+static const struct file_operations perf_fops = {
+	.llseek			= no_llseek,
+	.release		= perf_release,
+	.read			= perf_read,
+	.poll			= perf_poll,
+	.unlocked_ioctl		= perf_ioctl,
+	.compat_ioctl		= perf_compat_ioctl,
+	.mmap			= perf_mmap,
+	.fasync			= perf_fasync,
+};
+
+/*
+ * Perf event wakeup
+ *
+ * If there's data, ensure we set the poll() state and publish everything
+ * to user-space before waking everybody up.
+ */
+
+static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
+{
+	/* only the parent has fasync state */
+	if (event->parent)
+		event = event->parent;
+	return &event->fasync;
+}
+
+void perf_event_wakeup(struct perf_event *event)
+{
+	ring_buffer_wakeup(event);
+
+	if (event->pending_kill) {
+		kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
+		event->pending_kill = 0;
+	}
+}
+
+static void perf_sigtrap(struct perf_event *event)
+{
+	/*
+	 * We'd expect this to only occur if the irq_work is delayed and either
+	 * ctx->task or current has changed in the meantime. This can be the
+	 * case on architectures that do not implement arch_irq_work_raise().
+	 */
+	if (WARN_ON_ONCE(event->ctx->task != current))
+		return;
+
+	/*
+	 * Both perf_pending_task() and perf_pending_irq() can race with the
+	 * task exiting.
+	 */
+	if (current->flags & PF_EXITING)
+		return;
+
+	send_sig_perf((void __user *)event->pending_addr,
+		      event->attr.type, event->attr.sig_data);
+}
+
+/*
+ * Deliver the pending work in-event-context or follow the context.
+ */
+static void __perf_pending_irq(struct perf_event *event)
+{
+	int cpu = READ_ONCE(event->oncpu);
+
+	/*
+	 * If the event isn't running; we done. event_sched_out() will have
+	 * taken care of things.
+	 */
+	if (cpu < 0)
+		return;
+
+	/*
+	 * Yay, we hit home and are in the context of the event.
+	 */
+	if (cpu == smp_processor_id()) {
+		if (event->pending_sigtrap) {
+			event->pending_sigtrap = 0;
+			perf_sigtrap(event);
+			local_dec(&event->ctx->nr_pending);
+		}
+		if (event->pending_disable) {
+			event->pending_disable = 0;
+			perf_event_disable_local(event);
+		}
+		return;
+	}
+
+	/*
+	 *  CPU-A			CPU-B
+	 *
+	 *  perf_event_disable_inatomic()
+	 *    @pending_disable = CPU-A;
+	 *    irq_work_queue();
+	 *
+	 *  sched-out
+	 *    @pending_disable = -1;
+	 *
+	 *				sched-in
+	 *				perf_event_disable_inatomic()
+	 *				  @pending_disable = CPU-B;
+	 *				  irq_work_queue(); // FAILS
+	 *
+	 *  irq_work_run()
+	 *    perf_pending_irq()
+	 *
+	 * But the event runs on CPU-B and wants disabling there.
+	 */
+	irq_work_queue_on(&event->pending_irq, cpu);
+}
+
+static void perf_pending_irq(struct irq_work *entry)
+{
+	struct perf_event *event = container_of(entry, struct perf_event, pending_irq);
+	int rctx;
+
+	/*
+	 * If we 'fail' here, that's OK, it means recursion is already disabled
+	 * and we won't recurse 'further'.
+	 */
+	rctx = perf_swevent_get_recursion_context();
+
+	/*
+	 * The wakeup isn't bound to the context of the event -- it can happen
+	 * irrespective of where the event is.
+	 */
+	if (event->pending_wakeup) {
+		event->pending_wakeup = 0;
+		perf_event_wakeup(event);
+	}
+
+	__perf_pending_irq(event);
+
+	if (rctx >= 0)
+		perf_swevent_put_recursion_context(rctx);
+}
+
+static void perf_pending_task(struct callback_head *head)
+{
+	struct perf_event *event = container_of(head, struct perf_event, pending_task);
+	int rctx;
+
+	/*
+	 * If we 'fail' here, that's OK, it means recursion is already disabled
+	 * and we won't recurse 'further'.
+	 */
+	preempt_disable_notrace();
+	rctx = perf_swevent_get_recursion_context();
+
+	if (event->pending_work) {
+		event->pending_work = 0;
+		perf_sigtrap(event);
+		local_dec(&event->ctx->nr_pending);
+	}
+
+	if (rctx >= 0)
+		perf_swevent_put_recursion_context(rctx);
+	preempt_enable_notrace();
+
+	put_event(event);
+}
+
+#ifdef CONFIG_GUEST_PERF_EVENTS
+struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
+
+DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state);
+DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip);
+DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr);
+
+void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
+{
+	if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
+		return;
+
+	rcu_assign_pointer(perf_guest_cbs, cbs);
+	static_call_update(__perf_guest_state, cbs->state);
+	static_call_update(__perf_guest_get_ip, cbs->get_ip);
+
+	/* Implementing ->handle_intel_pt_intr is optional. */
+	if (cbs->handle_intel_pt_intr)
+		static_call_update(__perf_guest_handle_intel_pt_intr,
+				   cbs->handle_intel_pt_intr);
+}
+EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
+
+void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
+{
+	if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
+		return;
+
+	rcu_assign_pointer(perf_guest_cbs, NULL);
+	static_call_update(__perf_guest_state, (void *)&__static_call_return0);
+	static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0);
+	static_call_update(__perf_guest_handle_intel_pt_intr,
+			   (void *)&__static_call_return0);
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
+#endif
+
+static void
+perf_output_sample_regs(struct perf_output_handle *handle,
+			struct pt_regs *regs, u64 mask)
+{
+	int bit;
+	DECLARE_BITMAP(_mask, 64);
+
+	bitmap_from_u64(_mask, mask);
+	for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
+		u64 val;
+
+		val = perf_reg_value(regs, bit);
+		perf_output_put(handle, val);
+	}
+}
+
+static void perf_sample_regs_user(struct perf_regs *regs_user,
+				  struct pt_regs *regs)
+{
+	if (user_mode(regs)) {
+		regs_user->abi = perf_reg_abi(current);
+		regs_user->regs = regs;
+	} else if (!(current->flags & PF_KTHREAD)) {
+		perf_get_regs_user(regs_user, regs);
+	} else {
+		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
+		regs_user->regs = NULL;
+	}
+}
+
+static void perf_sample_regs_intr(struct perf_regs *regs_intr,
+				  struct pt_regs *regs)
+{
+	regs_intr->regs = regs;
+	regs_intr->abi  = perf_reg_abi(current);
+}
+
+
+/*
+ * Get remaining task size from user stack pointer.
+ *
+ * It'd be better to take stack vma map and limit this more
+ * precisely, but there's no way to get it safely under interrupt,
+ * so using TASK_SIZE as limit.
+ */
+static u64 perf_ustack_task_size(struct pt_regs *regs)
+{
+	unsigned long addr = perf_user_stack_pointer(regs);
+
+	if (!addr || addr >= TASK_SIZE)
+		return 0;
+
+	return TASK_SIZE - addr;
+}
+
+static u16
+perf_sample_ustack_size(u16 stack_size, u16 header_size,
+			struct pt_regs *regs)
+{
+	u64 task_size;
+
+	/* No regs, no stack pointer, no dump. */
+	if (!regs)
+		return 0;
+
+	/*
+	 * Check if we fit in with the requested stack size into the:
+	 * - TASK_SIZE
+	 *   If we don't, we limit the size to the TASK_SIZE.
+	 *
+	 * - remaining sample size
+	 *   If we don't, we customize the stack size to
+	 *   fit in to the remaining sample size.
+	 */
+
+	task_size  = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
+	stack_size = min(stack_size, (u16) task_size);
+
+	/* Current header size plus static size and dynamic size. */
+	header_size += 2 * sizeof(u64);
+
+	/* Do we fit in with the current stack dump size? */
+	if ((u16) (header_size + stack_size) < header_size) {
+		/*
+		 * If we overflow the maximum size for the sample,
+		 * we customize the stack dump size to fit in.
+		 */
+		stack_size = USHRT_MAX - header_size - sizeof(u64);
+		stack_size = round_up(stack_size, sizeof(u64));
+	}
+
+	return stack_size;
+}
+
+static void
+perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
+			  struct pt_regs *regs)
+{
+	/* Case of a kernel thread, nothing to dump */
+	if (!regs) {
+		u64 size = 0;
+		perf_output_put(handle, size);
+	} else {
+		unsigned long sp;
+		unsigned int rem;
+		u64 dyn_size;
+
+		/*
+		 * We dump:
+		 * static size
+		 *   - the size requested by user or the best one we can fit
+		 *     in to the sample max size
+		 * data
+		 *   - user stack dump data
+		 * dynamic size
+		 *   - the actual dumped size
+		 */
+
+		/* Static size. */
+		perf_output_put(handle, dump_size);
+
+		/* Data. */
+		sp = perf_user_stack_pointer(regs);
+		rem = __output_copy_user(handle, (void *) sp, dump_size);
+		dyn_size = dump_size - rem;
+
+		perf_output_skip(handle, rem);
+
+		/* Dynamic size. */
+		perf_output_put(handle, dyn_size);
+	}
+}
+
+static unsigned long perf_prepare_sample_aux(struct perf_event *event,
+					  struct perf_sample_data *data,
+					  size_t size)
+{
+	struct perf_event *sampler = event->aux_event;
+	struct perf_buffer *rb;
+
+	data->aux_size = 0;
+
+	if (!sampler)
+		goto out;
+
+	if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
+		goto out;
+
+	if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
+		goto out;
+
+	rb = ring_buffer_get(sampler);
+	if (!rb)
+		goto out;
+
+	/*
+	 * If this is an NMI hit inside sampling code, don't take
+	 * the sample. See also perf_aux_sample_output().
+	 */
+	if (READ_ONCE(rb->aux_in_sampling)) {
+		data->aux_size = 0;
+	} else {
+		size = min_t(size_t, size, perf_aux_size(rb));
+		data->aux_size = ALIGN(size, sizeof(u64));
+	}
+	ring_buffer_put(rb);
+
+out:
+	return data->aux_size;
+}
+
+static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
+                                 struct perf_event *event,
+                                 struct perf_output_handle *handle,
+                                 unsigned long size)
+{
+	unsigned long flags;
+	long ret;
+
+	/*
+	 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
+	 * paths. If we start calling them in NMI context, they may race with
+	 * the IRQ ones, that is, for example, re-starting an event that's just
+	 * been stopped, which is why we're using a separate callback that
+	 * doesn't change the event state.
+	 *
+	 * IRQs need to be disabled to prevent IPIs from racing with us.
+	 */
+	local_irq_save(flags);
+	/*
+	 * Guard against NMI hits inside the critical section;
+	 * see also perf_prepare_sample_aux().
+	 */
+	WRITE_ONCE(rb->aux_in_sampling, 1);
+	barrier();
+
+	ret = event->pmu->snapshot_aux(event, handle, size);
+
+	barrier();
+	WRITE_ONCE(rb->aux_in_sampling, 0);
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static void perf_aux_sample_output(struct perf_event *event,
+				   struct perf_output_handle *handle,
+				   struct perf_sample_data *data)
+{
+	struct perf_event *sampler = event->aux_event;
+	struct perf_buffer *rb;
+	unsigned long pad;
+	long size;
+
+	if (WARN_ON_ONCE(!sampler || !data->aux_size))
+		return;
+
+	rb = ring_buffer_get(sampler);
+	if (!rb)
+		return;
+
+	size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
+
+	/*
+	 * An error here means that perf_output_copy() failed (returned a
+	 * non-zero surplus that it didn't copy), which in its current
+	 * enlightened implementation is not possible. If that changes, we'd
+	 * like to know.
+	 */
+	if (WARN_ON_ONCE(size < 0))
+		goto out_put;
+
+	/*
+	 * The pad comes from ALIGN()ing data->aux_size up to u64 in
+	 * perf_prepare_sample_aux(), so should not be more than that.
+	 */
+	pad = data->aux_size - size;
+	if (WARN_ON_ONCE(pad >= sizeof(u64)))
+		pad = 8;
+
+	if (pad) {
+		u64 zero = 0;
+		perf_output_copy(handle, &zero, pad);
+	}
+
+out_put:
+	ring_buffer_put(rb);
+}
+
+static void __perf_event_header__init_id(struct perf_event_header *header,
+					 struct perf_sample_data *data,
+					 struct perf_event *event,
+					 u64 sample_type)
+{
+	data->type = event->attr.sample_type;
+	header->size += event->id_header_size;
+
+	if (sample_type & PERF_SAMPLE_TID) {
+		/* namespace issues */
+		data->tid_entry.pid = perf_event_pid(event, current);
+		data->tid_entry.tid = perf_event_tid(event, current);
+	}
+
+	if (sample_type & PERF_SAMPLE_TIME)
+		data->time = perf_event_clock(event);
+
+	if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
+		data->id = primary_event_id(event);
+
+	if (sample_type & PERF_SAMPLE_STREAM_ID)
+		data->stream_id = event->id;
+
+	if (sample_type & PERF_SAMPLE_CPU) {
+		data->cpu_entry.cpu	 = raw_smp_processor_id();
+		data->cpu_entry.reserved = 0;
+	}
+}
+
+void perf_event_header__init_id(struct perf_event_header *header,
+				struct perf_sample_data *data,
+				struct perf_event *event)
+{
+	if (event->attr.sample_id_all)
+		__perf_event_header__init_id(header, data, event, event->attr.sample_type);
+}
+
+static void __perf_event__output_id_sample(struct perf_output_handle *handle,
+					   struct perf_sample_data *data)
+{
+	u64 sample_type = data->type;
+
+	if (sample_type & PERF_SAMPLE_TID)
+		perf_output_put(handle, data->tid_entry);
+
+	if (sample_type & PERF_SAMPLE_TIME)
+		perf_output_put(handle, data->time);
+
+	if (sample_type & PERF_SAMPLE_ID)
+		perf_output_put(handle, data->id);
+
+	if (sample_type & PERF_SAMPLE_STREAM_ID)
+		perf_output_put(handle, data->stream_id);
+
+	if (sample_type & PERF_SAMPLE_CPU)
+		perf_output_put(handle, data->cpu_entry);
+
+	if (sample_type & PERF_SAMPLE_IDENTIFIER)
+		perf_output_put(handle, data->id);
+}
+
+void perf_event__output_id_sample(struct perf_event *event,
+				  struct perf_output_handle *handle,
+				  struct perf_sample_data *sample)
+{
+	if (event->attr.sample_id_all)
+		__perf_event__output_id_sample(handle, sample);
+}
+
+static void perf_output_read_one(struct perf_output_handle *handle,
+				 struct perf_event *event,
+				 u64 enabled, u64 running)
+{
+	u64 read_format = event->attr.read_format;
+	u64 values[5];
+	int n = 0;
+
+	values[n++] = perf_event_count(event);
+	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
+		values[n++] = enabled +
+			atomic64_read(&event->child_total_time_enabled);
+	}
+	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
+		values[n++] = running +
+			atomic64_read(&event->child_total_time_running);
+	}
+	if (read_format & PERF_FORMAT_ID)
+		values[n++] = primary_event_id(event);
+	if (read_format & PERF_FORMAT_LOST)
+		values[n++] = atomic64_read(&event->lost_samples);
+
+	__output_copy(handle, values, n * sizeof(u64));
+}
+
+static void perf_output_read_group(struct perf_output_handle *handle,
+			    struct perf_event *event,
+			    u64 enabled, u64 running)
+{
+	struct perf_event *leader = event->group_leader, *sub;
+	u64 read_format = event->attr.read_format;
+	unsigned long flags;
+	u64 values[6];
+	int n = 0;
+
+	/*
+	 * Disabling interrupts avoids all counter scheduling
+	 * (context switches, timer based rotation and IPIs).
+	 */
+	local_irq_save(flags);
+
+	values[n++] = 1 + leader->nr_siblings;
+
+	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+		values[n++] = enabled;
+
+	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+		values[n++] = running;
+
+	if ((leader != event) &&
+	    (leader->state == PERF_EVENT_STATE_ACTIVE))
+		leader->pmu->read(leader);
+
+	values[n++] = perf_event_count(leader);
+	if (read_format & PERF_FORMAT_ID)
+		values[n++] = primary_event_id(leader);
+	if (read_format & PERF_FORMAT_LOST)
+		values[n++] = atomic64_read(&leader->lost_samples);
+
+	__output_copy(handle, values, n * sizeof(u64));
+
+	for_each_sibling_event(sub, leader) {
+		n = 0;
+
+		if ((sub != event) &&
+		    (sub->state == PERF_EVENT_STATE_ACTIVE))
+			sub->pmu->read(sub);
+
+		values[n++] = perf_event_count(sub);
+		if (read_format & PERF_FORMAT_ID)
+			values[n++] = primary_event_id(sub);
+		if (read_format & PERF_FORMAT_LOST)
+			values[n++] = atomic64_read(&sub->lost_samples);
+
+		__output_copy(handle, values, n * sizeof(u64));
+	}
+
+	local_irq_restore(flags);
+}
+
+#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
+				 PERF_FORMAT_TOTAL_TIME_RUNNING)
+
+/*
+ * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
+ *
+ * The problem is that its both hard and excessively expensive to iterate the
+ * child list, not to mention that its impossible to IPI the children running
+ * on another CPU, from interrupt/NMI context.
+ */
+static void perf_output_read(struct perf_output_handle *handle,
+			     struct perf_event *event)
+{
+	u64 enabled = 0, running = 0, now;
+	u64 read_format = event->attr.read_format;
+
+	/*
+	 * compute total_time_enabled, total_time_running
+	 * based on snapshot values taken when the event
+	 * was last scheduled in.
+	 *
+	 * we cannot simply called update_context_time()
+	 * because of locking issue as we are called in
+	 * NMI context
+	 */
+	if (read_format & PERF_FORMAT_TOTAL_TIMES)
+		calc_timer_values(event, &now, &enabled, &running);
+
+	if (event->attr.read_format & PERF_FORMAT_GROUP)
+		perf_output_read_group(handle, event, enabled, running);
+	else
+		perf_output_read_one(handle, event, enabled, running);
+}
+
+void perf_output_sample(struct perf_output_handle *handle,
+			struct perf_event_header *header,
+			struct perf_sample_data *data,
+			struct perf_event *event)
+{
+	u64 sample_type = data->type;
+
+	perf_output_put(handle, *header);
+
+	if (sample_type & PERF_SAMPLE_IDENTIFIER)
+		perf_output_put(handle, data->id);
+
+	if (sample_type & PERF_SAMPLE_IP)
+		perf_output_put(handle, data->ip);
+
+	if (sample_type & PERF_SAMPLE_TID)
+		perf_output_put(handle, data->tid_entry);
+
+	if (sample_type & PERF_SAMPLE_TIME)
+		perf_output_put(handle, data->time);
+
+	if (sample_type & PERF_SAMPLE_ADDR)
+		perf_output_put(handle, data->addr);
+
+	if (sample_type & PERF_SAMPLE_ID)
+		perf_output_put(handle, data->id);
+
+	if (sample_type & PERF_SAMPLE_STREAM_ID)
+		perf_output_put(handle, data->stream_id);
+
+	if (sample_type & PERF_SAMPLE_CPU)
+		perf_output_put(handle, data->cpu_entry);
+
+	if (sample_type & PERF_SAMPLE_PERIOD)
+		perf_output_put(handle, data->period);
+
+	if (sample_type & PERF_SAMPLE_READ)
+		perf_output_read(handle, event);
+
+	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
+		int size = 1;
+
+		size += data->callchain->nr;
+		size *= sizeof(u64);
+		__output_copy(handle, data->callchain, size);
+	}
+
+	if (sample_type & PERF_SAMPLE_RAW) {
+		struct perf_raw_record *raw = data->raw;
+
+		if (raw) {
+			struct perf_raw_frag *frag = &raw->frag;
+
+			perf_output_put(handle, raw->size);
+			do {
+				if (frag->copy) {
+					__output_custom(handle, frag->copy,
+							frag->data, frag->size);
+				} else {
+					__output_copy(handle, frag->data,
+						      frag->size);
+				}
+				if (perf_raw_frag_last(frag))
+					break;
+				frag = frag->next;
+			} while (1);
+			if (frag->pad)
+				__output_skip(handle, NULL, frag->pad);
+		} else {
+			struct {
+				u32	size;
+				u32	data;
+			} raw = {
+				.size = sizeof(u32),
+				.data = 0,
+			};
+			perf_output_put(handle, raw);
+		}
+	}
+
+	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
+		if (data->sample_flags & PERF_SAMPLE_BRANCH_STACK) {
+			size_t size;
+
+			size = data->br_stack->nr
+			     * sizeof(struct perf_branch_entry);
+
+			perf_output_put(handle, data->br_stack->nr);
+			if (branch_sample_hw_index(event))
+				perf_output_put(handle, data->br_stack->hw_idx);
+			perf_output_copy(handle, data->br_stack->entries, size);
+		} else {
+			/*
+			 * we always store at least the value of nr
+			 */
+			u64 nr = 0;
+			perf_output_put(handle, nr);
+		}
+	}
+
+	if (sample_type & PERF_SAMPLE_REGS_USER) {
+		u64 abi = data->regs_user.abi;
+
+		/*
+		 * If there are no regs to dump, notice it through
+		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
+		 */
+		perf_output_put(handle, abi);
+
+		if (abi) {
+			u64 mask = event->attr.sample_regs_user;
+			perf_output_sample_regs(handle,
+						data->regs_user.regs,
+						mask);
+		}
+	}
+
+	if (sample_type & PERF_SAMPLE_STACK_USER) {
+		perf_output_sample_ustack(handle,
+					  data->stack_user_size,
+					  data->regs_user.regs);
+	}
+
+	if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
+		perf_output_put(handle, data->weight.full);
+
+	if (sample_type & PERF_SAMPLE_DATA_SRC)
+		perf_output_put(handle, data->data_src.val);
+
+	if (sample_type & PERF_SAMPLE_TRANSACTION)
+		perf_output_put(handle, data->txn);
+
+	if (sample_type & PERF_SAMPLE_REGS_INTR) {
+		u64 abi = data->regs_intr.abi;
+		/*
+		 * If there are no regs to dump, notice it through
+		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
+		 */
+		perf_output_put(handle, abi);
+
+		if (abi) {
+			u64 mask = event->attr.sample_regs_intr;
+
+			perf_output_sample_regs(handle,
+						data->regs_intr.regs,
+						mask);
+		}
+	}
+
+	if (sample_type & PERF_SAMPLE_PHYS_ADDR)
+		perf_output_put(handle, data->phys_addr);
+
+	if (sample_type & PERF_SAMPLE_CGROUP)
+		perf_output_put(handle, data->cgroup);
+
+	if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
+		perf_output_put(handle, data->data_page_size);
+
+	if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
+		perf_output_put(handle, data->code_page_size);
+
+	if (sample_type & PERF_SAMPLE_AUX) {
+		perf_output_put(handle, data->aux_size);
+
+		if (data->aux_size)
+			perf_aux_sample_output(event, handle, data);
+	}
+
+	if (!event->attr.watermark) {
+		int wakeup_events = event->attr.wakeup_events;
+
+		if (wakeup_events) {
+			struct perf_buffer *rb = handle->rb;
+			int events = local_inc_return(&rb->events);
+
+			if (events >= wakeup_events) {
+				local_sub(wakeup_events, &rb->events);
+				local_inc(&rb->wakeup);
+			}
+		}
+	}
+}
+
+static u64 perf_virt_to_phys(u64 virt)
+{
+	u64 phys_addr = 0;
+
+	if (!virt)
+		return 0;
+
+	if (virt >= TASK_SIZE) {
+		/* If it's vmalloc()d memory, leave phys_addr as 0 */
+		if (virt_addr_valid((void *)(uintptr_t)virt) &&
+		    !(virt >= VMALLOC_START && virt < VMALLOC_END))
+			phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
+	} else {
+		/*
+		 * Walking the pages tables for user address.
+		 * Interrupts are disabled, so it prevents any tear down
+		 * of the page tables.
+		 * Try IRQ-safe get_user_page_fast_only first.
+		 * If failed, leave phys_addr as 0.
+		 */
+		if (current->mm != NULL) {
+			struct page *p;
+
+			pagefault_disable();
+			if (get_user_page_fast_only(virt, 0, &p)) {
+				phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
+				put_page(p);
+			}
+			pagefault_enable();
+		}
+	}
+
+	return phys_addr;
+}
+
+/*
+ * Return the pagetable size of a given virtual address.
+ */
+static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
+{
+	u64 size = 0;
+
+#ifdef CONFIG_HAVE_FAST_GUP
+	pgd_t *pgdp, pgd;
+	p4d_t *p4dp, p4d;
+	pud_t *pudp, pud;
+	pmd_t *pmdp, pmd;
+	pte_t *ptep, pte;
+
+	pgdp = pgd_offset(mm, addr);
+	pgd = READ_ONCE(*pgdp);
+	if (pgd_none(pgd))
+		return 0;
+
+	if (pgd_leaf(pgd))
+		return pgd_leaf_size(pgd);
+
+	p4dp = p4d_offset_lockless(pgdp, pgd, addr);
+	p4d = READ_ONCE(*p4dp);
+	if (!p4d_present(p4d))
+		return 0;
+
+	if (p4d_leaf(p4d))
+		return p4d_leaf_size(p4d);
+
+	pudp = pud_offset_lockless(p4dp, p4d, addr);
+	pud = READ_ONCE(*pudp);
+	if (!pud_present(pud))
+		return 0;
+
+	if (pud_leaf(pud))
+		return pud_leaf_size(pud);
+
+	pmdp = pmd_offset_lockless(pudp, pud, addr);
+	pmd = READ_ONCE(*pmdp);
+	if (!pmd_present(pmd))
+		return 0;
+
+	if (pmd_leaf(pmd))
+		return pmd_leaf_size(pmd);
+
+	ptep = pte_offset_map(&pmd, addr);
+	pte = ptep_get_lockless(ptep);
+	if (pte_present(pte))
+		size = pte_leaf_size(pte);
+	pte_unmap(ptep);
+#endif /* CONFIG_HAVE_FAST_GUP */
+
+	return size;
+}
+
+static u64 perf_get_page_size(unsigned long addr)
+{
+	struct mm_struct *mm;
+	unsigned long flags;
+	u64 size;
+
+	if (!addr)
+		return 0;
+
+	/*
+	 * Software page-table walkers must disable IRQs,
+	 * which prevents any tear down of the page tables.
+	 */
+	local_irq_save(flags);
+
+	mm = current->mm;
+	if (!mm) {
+		/*
+		 * For kernel threads and the like, use init_mm so that
+		 * we can find kernel memory.
+		 */
+		mm = &init_mm;
+	}
+
+	size = perf_get_pgtable_size(mm, addr);
+
+	local_irq_restore(flags);
+
+	return size;
+}
+
+static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
+
+struct perf_callchain_entry *
+perf_callchain(struct perf_event *event, struct pt_regs *regs)
+{
+	bool kernel = !event->attr.exclude_callchain_kernel;
+	bool user   = !event->attr.exclude_callchain_user;
+	/* Disallow cross-task user callchains. */
+	bool crosstask = event->ctx->task && event->ctx->task != current;
+	const u32 max_stack = event->attr.sample_max_stack;
+	struct perf_callchain_entry *callchain;
+
+	if (!kernel && !user)
+		return &__empty_callchain;
+
+	callchain = get_perf_callchain(regs, 0, kernel, user,
+				       max_stack, crosstask, true);
+	return callchain ?: &__empty_callchain;
+}
+
+void perf_prepare_sample(struct perf_event_header *header,
+			 struct perf_sample_data *data,
+			 struct perf_event *event,
+			 struct pt_regs *regs)
+{
+	u64 sample_type = event->attr.sample_type;
+	u64 filtered_sample_type;
+
+	header->type = PERF_RECORD_SAMPLE;
+	header->size = sizeof(*header) + event->header_size;
+
+	header->misc = 0;
+	header->misc |= perf_misc_flags(regs);
+
+	/*
+	 * Clear the sample flags that have already been done by the
+	 * PMU driver.
+	 */
+	filtered_sample_type = sample_type & ~data->sample_flags;
+	__perf_event_header__init_id(header, data, event, filtered_sample_type);
+
+	if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
+		data->ip = perf_instruction_pointer(regs);
+
+	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
+		int size = 1;
+
+		if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN)
+			data->callchain = perf_callchain(event, regs);
+
+		size += data->callchain->nr;
+
+		header->size += size * sizeof(u64);
+	}
+
+	if (sample_type & PERF_SAMPLE_RAW) {
+		struct perf_raw_record *raw = data->raw;
+		int size;
+
+		if (raw && (data->sample_flags & PERF_SAMPLE_RAW)) {
+			struct perf_raw_frag *frag = &raw->frag;
+			u32 sum = 0;
+
+			do {
+				sum += frag->size;
+				if (perf_raw_frag_last(frag))
+					break;
+				frag = frag->next;
+			} while (1);
+
+			size = round_up(sum + sizeof(u32), sizeof(u64));
+			raw->size = size - sizeof(u32);
+			frag->pad = raw->size - sum;
+		} else {
+			size = sizeof(u64);
+			data->raw = NULL;
+		}
+
+		header->size += size;
+	}
+
+	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
+		int size = sizeof(u64); /* nr */
+		if (data->sample_flags & PERF_SAMPLE_BRANCH_STACK) {
+			if (branch_sample_hw_index(event))
+				size += sizeof(u64);
+
+			size += data->br_stack->nr
+			      * sizeof(struct perf_branch_entry);
+		}
+		header->size += size;
+	}
+
+	if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
+		perf_sample_regs_user(&data->regs_user, regs);
+
+	if (sample_type & PERF_SAMPLE_REGS_USER) {
+		/* regs dump ABI info */
+		int size = sizeof(u64);
+
+		if (data->regs_user.regs) {
+			u64 mask = event->attr.sample_regs_user;
+			size += hweight64(mask) * sizeof(u64);
+		}
+
+		header->size += size;
+	}
+
+	if (sample_type & PERF_SAMPLE_STACK_USER) {
+		/*
+		 * Either we need PERF_SAMPLE_STACK_USER bit to be always
+		 * processed as the last one or have additional check added
+		 * in case new sample type is added, because we could eat
+		 * up the rest of the sample size.
+		 */
+		u16 stack_size = event->attr.sample_stack_user;
+		u16 size = sizeof(u64);
+
+		stack_size = perf_sample_ustack_size(stack_size, header->size,
+						     data->regs_user.regs);
+
+		/*
+		 * If there is something to dump, add space for the dump
+		 * itself and for the field that tells the dynamic size,
+		 * which is how many have been actually dumped.
+		 */
+		if (stack_size)
+			size += sizeof(u64) + stack_size;
+
+		data->stack_user_size = stack_size;
+		header->size += size;
+	}
+
+	if (filtered_sample_type & PERF_SAMPLE_WEIGHT_TYPE)
+		data->weight.full = 0;
+
+	if (filtered_sample_type & PERF_SAMPLE_DATA_SRC)
+		data->data_src.val = PERF_MEM_NA;
+
+	if (filtered_sample_type & PERF_SAMPLE_TRANSACTION)
+		data->txn = 0;
+
+	if (sample_type & (PERF_SAMPLE_ADDR | PERF_SAMPLE_PHYS_ADDR | PERF_SAMPLE_DATA_PAGE_SIZE)) {
+		if (filtered_sample_type & PERF_SAMPLE_ADDR)
+			data->addr = 0;
+	}
+
+	if (sample_type & PERF_SAMPLE_REGS_INTR) {
+		/* regs dump ABI info */
+		int size = sizeof(u64);
+
+		perf_sample_regs_intr(&data->regs_intr, regs);
+
+		if (data->regs_intr.regs) {
+			u64 mask = event->attr.sample_regs_intr;
+
+			size += hweight64(mask) * sizeof(u64);
+		}
+
+		header->size += size;
+	}
+
+	if (sample_type & PERF_SAMPLE_PHYS_ADDR &&
+	    filtered_sample_type & PERF_SAMPLE_PHYS_ADDR)
+		data->phys_addr = perf_virt_to_phys(data->addr);
+
+#ifdef CONFIG_CGROUP_PERF
+	if (sample_type & PERF_SAMPLE_CGROUP) {
+		struct cgroup *cgrp;
+
+		/* protected by RCU */
+		cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
+		data->cgroup = cgroup_id(cgrp);
+	}
+#endif
+
+	/*
+	 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
+	 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
+	 * but the value will not dump to the userspace.
+	 */
+	if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
+		data->data_page_size = perf_get_page_size(data->addr);
+
+	if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
+		data->code_page_size = perf_get_page_size(data->ip);
+
+	if (sample_type & PERF_SAMPLE_AUX) {
+		u64 size;
+
+		header->size += sizeof(u64); /* size */
+
+		/*
+		 * Given the 16bit nature of header::size, an AUX sample can
+		 * easily overflow it, what with all the preceding sample bits.
+		 * Make sure this doesn't happen by using up to U16_MAX bytes
+		 * per sample in total (rounded down to 8 byte boundary).
+		 */
+		size = min_t(size_t, U16_MAX - header->size,
+			     event->attr.aux_sample_size);
+		size = rounddown(size, 8);
+		size = perf_prepare_sample_aux(event, data, size);
+
+		WARN_ON_ONCE(size + header->size > U16_MAX);
+		header->size += size;
+	}
+	/*
+	 * If you're adding more sample types here, you likely need to do
+	 * something about the overflowing header::size, like repurpose the
+	 * lowest 3 bits of size, which should be always zero at the moment.
+	 * This raises a more important question, do we really need 512k sized
+	 * samples and why, so good argumentation is in order for whatever you
+	 * do here next.
+	 */
+	WARN_ON_ONCE(header->size & 7);
+}
+
+static __always_inline int
+__perf_event_output(struct perf_event *event,
+		    struct perf_sample_data *data,
+		    struct pt_regs *regs,
+		    int (*output_begin)(struct perf_output_handle *,
+					struct perf_sample_data *,
+					struct perf_event *,
+					unsigned int))
+{
+	struct perf_output_handle handle;
+	struct perf_event_header header;
+	int err;
+
+	/* protect the callchain buffers */
+	rcu_read_lock();
+
+	perf_prepare_sample(&header, data, event, regs);
+
+	err = output_begin(&handle, data, event, header.size);
+	if (err)
+		goto exit;
+
+	perf_output_sample(&handle, &header, data, event);
+
+	perf_output_end(&handle);
+
+exit:
+	rcu_read_unlock();
+	return err;
+}
+
+void
+perf_event_output_forward(struct perf_event *event,
+			 struct perf_sample_data *data,
+			 struct pt_regs *regs)
+{
+	__perf_event_output(event, data, regs, perf_output_begin_forward);
+}
+
+void
+perf_event_output_backward(struct perf_event *event,
+			   struct perf_sample_data *data,
+			   struct pt_regs *regs)
+{
+	__perf_event_output(event, data, regs, perf_output_begin_backward);
+}
+
+int
+perf_event_output(struct perf_event *event,
+		  struct perf_sample_data *data,
+		  struct pt_regs *regs)
+{
+	return __perf_event_output(event, data, regs, perf_output_begin);
+}
+
+/*
+ * read event_id
+ */
+
+struct perf_read_event {
+	struct perf_event_header	header;
+
+	u32				pid;
+	u32				tid;
+};
+
+static void
+perf_event_read_event(struct perf_event *event,
+			struct task_struct *task)
+{
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	struct perf_read_event read_event = {
+		.header = {
+			.type = PERF_RECORD_READ,
+			.misc = 0,
+			.size = sizeof(read_event) + event->read_size,
+		},
+		.pid = perf_event_pid(event, task),
+		.tid = perf_event_tid(event, task),
+	};
+	int ret;
+
+	perf_event_header__init_id(&read_event.header, &sample, event);
+	ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
+	if (ret)
+		return;
+
+	perf_output_put(&handle, read_event);
+	perf_output_read(&handle, event);
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+}
+
+typedef void (perf_iterate_f)(struct perf_event *event, void *data);
+
+static void
+perf_iterate_ctx(struct perf_event_context *ctx,
+		   perf_iterate_f output,
+		   void *data, bool all)
+{
+	struct perf_event *event;
+
+	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+		if (!all) {
+			if (event->state < PERF_EVENT_STATE_INACTIVE)
+				continue;
+			if (!event_filter_match(event))
+				continue;
+		}
+
+		output(event, data);
+	}
+}
+
+static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
+{
+	struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
+	struct perf_event *event;
+
+	list_for_each_entry_rcu(event, &pel->list, sb_list) {
+		/*
+		 * Skip events that are not fully formed yet; ensure that
+		 * if we observe event->ctx, both event and ctx will be
+		 * complete enough. See perf_install_in_context().
+		 */
+		if (!smp_load_acquire(&event->ctx))
+			continue;
+
+		if (event->state < PERF_EVENT_STATE_INACTIVE)
+			continue;
+		if (!event_filter_match(event))
+			continue;
+		output(event, data);
+	}
+}
+
+/*
+ * Iterate all events that need to receive side-band events.
+ *
+ * For new callers; ensure that account_pmu_sb_event() includes
+ * your event, otherwise it might not get delivered.
+ */
+static void
+perf_iterate_sb(perf_iterate_f output, void *data,
+	       struct perf_event_context *task_ctx)
+{
+	struct perf_event_context *ctx;
+	int ctxn;
+
+	rcu_read_lock();
+	preempt_disable();
+
+	/*
+	 * If we have task_ctx != NULL we only notify the task context itself.
+	 * The task_ctx is set only for EXIT events before releasing task
+	 * context.
+	 */
+	if (task_ctx) {
+		perf_iterate_ctx(task_ctx, output, data, false);
+		goto done;
+	}
+
+	perf_iterate_sb_cpu(output, data);
+
+	for_each_task_context_nr(ctxn) {
+		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
+		if (ctx)
+			perf_iterate_ctx(ctx, output, data, false);
+	}
+done:
+	preempt_enable();
+	rcu_read_unlock();
+}
+
+/*
+ * Clear all file-based filters at exec, they'll have to be
+ * re-instated when/if these objects are mmapped again.
+ */
+static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
+{
+	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
+	struct perf_addr_filter *filter;
+	unsigned int restart = 0, count = 0;
+	unsigned long flags;
+
+	if (!has_addr_filter(event))
+		return;
+
+	raw_spin_lock_irqsave(&ifh->lock, flags);
+	list_for_each_entry(filter, &ifh->list, entry) {
+		if (filter->path.dentry) {
+			event->addr_filter_ranges[count].start = 0;
+			event->addr_filter_ranges[count].size = 0;
+			restart++;
+		}
+
+		count++;
+	}
+
+	if (restart)
+		event->addr_filters_gen++;
+	raw_spin_unlock_irqrestore(&ifh->lock, flags);
+
+	if (restart)
+		perf_event_stop(event, 1);
+}
+
+void perf_event_exec(void)
+{
+	struct perf_event_context *ctx;
+	int ctxn;
+
+	for_each_task_context_nr(ctxn) {
+		perf_event_enable_on_exec(ctxn);
+		perf_event_remove_on_exec(ctxn);
+
+		rcu_read_lock();
+		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
+		if (ctx) {
+			perf_iterate_ctx(ctx, perf_event_addr_filters_exec,
+					 NULL, true);
+		}
+		rcu_read_unlock();
+	}
+}
+
+struct remote_output {
+	struct perf_buffer	*rb;
+	int			err;
+};
+
+static void __perf_event_output_stop(struct perf_event *event, void *data)
+{
+	struct perf_event *parent = event->parent;
+	struct remote_output *ro = data;
+	struct perf_buffer *rb = ro->rb;
+	struct stop_event_data sd = {
+		.event	= event,
+	};
+
+	if (!has_aux(event))
+		return;
+
+	if (!parent)
+		parent = event;
+
+	/*
+	 * In case of inheritance, it will be the parent that links to the
+	 * ring-buffer, but it will be the child that's actually using it.
+	 *
+	 * We are using event::rb to determine if the event should be stopped,
+	 * however this may race with ring_buffer_attach() (through set_output),
+	 * which will make us skip the event that actually needs to be stopped.
+	 * So ring_buffer_attach() has to stop an aux event before re-assigning
+	 * its rb pointer.
+	 */
+	if (rcu_dereference(parent->rb) == rb)
+		ro->err = __perf_event_stop(&sd);
+}
+
+static int __perf_pmu_output_stop(void *info)
+{
+	struct perf_event *event = info;
+	struct pmu *pmu = event->ctx->pmu;
+	struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+	struct remote_output ro = {
+		.rb	= event->rb,
+	};
+
+	rcu_read_lock();
+	perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
+	if (cpuctx->task_ctx)
+		perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
+				   &ro, false);
+	rcu_read_unlock();
+
+	return ro.err;
+}
+
+static void perf_pmu_output_stop(struct perf_event *event)
+{
+	struct perf_event *iter;
+	int err, cpu;
+
+restart:
+	rcu_read_lock();
+	list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
+		/*
+		 * For per-CPU events, we need to make sure that neither they
+		 * nor their children are running; for cpu==-1 events it's
+		 * sufficient to stop the event itself if it's active, since
+		 * it can't have children.
+		 */
+		cpu = iter->cpu;
+		if (cpu == -1)
+			cpu = READ_ONCE(iter->oncpu);
+
+		if (cpu == -1)
+			continue;
+
+		err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
+		if (err == -EAGAIN) {
+			rcu_read_unlock();
+			goto restart;
+		}
+	}
+	rcu_read_unlock();
+}
+
+/*
+ * task tracking -- fork/exit
+ *
+ * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
+ */
+
+struct perf_task_event {
+	struct task_struct		*task;
+	struct perf_event_context	*task_ctx;
+
+	struct {
+		struct perf_event_header	header;
+
+		u32				pid;
+		u32				ppid;
+		u32				tid;
+		u32				ptid;
+		u64				time;
+	} event_id;
+};
+
+static int perf_event_task_match(struct perf_event *event)
+{
+	return event->attr.comm  || event->attr.mmap ||
+	       event->attr.mmap2 || event->attr.mmap_data ||
+	       event->attr.task;
+}
+
+static void perf_event_task_output(struct perf_event *event,
+				   void *data)
+{
+	struct perf_task_event *task_event = data;
+	struct perf_output_handle handle;
+	struct perf_sample_data	sample;
+	struct task_struct *task = task_event->task;
+	int ret, size = task_event->event_id.header.size;
+
+	if (!perf_event_task_match(event))
+		return;
+
+	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
+
+	ret = perf_output_begin(&handle, &sample, event,
+				task_event->event_id.header.size);
+	if (ret)
+		goto out;
+
+	task_event->event_id.pid = perf_event_pid(event, task);
+	task_event->event_id.tid = perf_event_tid(event, task);
+
+	if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
+		task_event->event_id.ppid = perf_event_pid(event,
+							task->real_parent);
+		task_event->event_id.ptid = perf_event_pid(event,
+							task->real_parent);
+	} else {  /* PERF_RECORD_FORK */
+		task_event->event_id.ppid = perf_event_pid(event, current);
+		task_event->event_id.ptid = perf_event_tid(event, current);
+	}
+
+	task_event->event_id.time = perf_event_clock(event);
+
+	perf_output_put(&handle, task_event->event_id);
+
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+out:
+	task_event->event_id.header.size = size;
+}
+
+static void perf_event_task(struct task_struct *task,
+			      struct perf_event_context *task_ctx,
+			      int new)
+{
+	struct perf_task_event task_event;
+
+	if (!atomic_read(&nr_comm_events) &&
+	    !atomic_read(&nr_mmap_events) &&
+	    !atomic_read(&nr_task_events))
+		return;
+
+	task_event = (struct perf_task_event){
+		.task	  = task,
+		.task_ctx = task_ctx,
+		.event_id    = {
+			.header = {
+				.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
+				.misc = 0,
+				.size = sizeof(task_event.event_id),
+			},
+			/* .pid  */
+			/* .ppid */
+			/* .tid  */
+			/* .ptid */
+			/* .time */
+		},
+	};
+
+	perf_iterate_sb(perf_event_task_output,
+		       &task_event,
+		       task_ctx);
+}
+
+void perf_event_fork(struct task_struct *task)
+{
+	perf_event_task(task, NULL, 1);
+	perf_event_namespaces(task);
+}
+
+/*
+ * comm tracking
+ */
+
+struct perf_comm_event {
+	struct task_struct	*task;
+	char			*comm;
+	int			comm_size;
+
+	struct {
+		struct perf_event_header	header;
+
+		u32				pid;
+		u32				tid;
+	} event_id;
+};
+
+static int perf_event_comm_match(struct perf_event *event)
+{
+	return event->attr.comm;
+}
+
+static void perf_event_comm_output(struct perf_event *event,
+				   void *data)
+{
+	struct perf_comm_event *comm_event = data;
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	int size = comm_event->event_id.header.size;
+	int ret;
+
+	if (!perf_event_comm_match(event))
+		return;
+
+	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
+	ret = perf_output_begin(&handle, &sample, event,
+				comm_event->event_id.header.size);
+
+	if (ret)
+		goto out;
+
+	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
+	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
+
+	perf_output_put(&handle, comm_event->event_id);
+	__output_copy(&handle, comm_event->comm,
+				   comm_event->comm_size);
+
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+out:
+	comm_event->event_id.header.size = size;
+}
+
+static void perf_event_comm_event(struct perf_comm_event *comm_event)
+{
+	char comm[TASK_COMM_LEN];
+	unsigned int size;
+
+	memset(comm, 0, sizeof(comm));
+	strlcpy(comm, comm_event->task->comm, sizeof(comm));
+	size = ALIGN(strlen(comm)+1, sizeof(u64));
+
+	comm_event->comm = comm;
+	comm_event->comm_size = size;
+
+	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
+
+	perf_iterate_sb(perf_event_comm_output,
+		       comm_event,
+		       NULL);
+}
+
+void perf_event_comm(struct task_struct *task, bool exec)
+{
+	struct perf_comm_event comm_event;
+
+	if (!atomic_read(&nr_comm_events))
+		return;
+
+	comm_event = (struct perf_comm_event){
+		.task	= task,
+		/* .comm      */
+		/* .comm_size */
+		.event_id  = {
+			.header = {
+				.type = PERF_RECORD_COMM,
+				.misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
+				/* .size */
+			},
+			/* .pid */
+			/* .tid */
+		},
+	};
+
+	perf_event_comm_event(&comm_event);
+}
+
+/*
+ * namespaces tracking
+ */
+
+struct perf_namespaces_event {
+	struct task_struct		*task;
+
+	struct {
+		struct perf_event_header	header;
+
+		u32				pid;
+		u32				tid;
+		u64				nr_namespaces;
+		struct perf_ns_link_info	link_info[NR_NAMESPACES];
+	} event_id;
+};
+
+static int perf_event_namespaces_match(struct perf_event *event)
+{
+	return event->attr.namespaces;
+}
+
+static void perf_event_namespaces_output(struct perf_event *event,
+					 void *data)
+{
+	struct perf_namespaces_event *namespaces_event = data;
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	u16 header_size = namespaces_event->event_id.header.size;
+	int ret;
+
+	if (!perf_event_namespaces_match(event))
+		return;
+
+	perf_event_header__init_id(&namespaces_event->event_id.header,
+				   &sample, event);
+	ret = perf_output_begin(&handle, &sample, event,
+				namespaces_event->event_id.header.size);
+	if (ret)
+		goto out;
+
+	namespaces_event->event_id.pid = perf_event_pid(event,
+							namespaces_event->task);
+	namespaces_event->event_id.tid = perf_event_tid(event,
+							namespaces_event->task);
+
+	perf_output_put(&handle, namespaces_event->event_id);
+
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+out:
+	namespaces_event->event_id.header.size = header_size;
+}
+
+static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
+				   struct task_struct *task,
+				   const struct proc_ns_operations *ns_ops)
+{
+	struct path ns_path;
+	struct inode *ns_inode;
+	int error;
+
+	error = ns_get_path(&ns_path, task, ns_ops);
+	if (!error) {
+		ns_inode = ns_path.dentry->d_inode;
+		ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
+		ns_link_info->ino = ns_inode->i_ino;
+		path_put(&ns_path);
+	}
+}
+
+void perf_event_namespaces(struct task_struct *task)
+{
+	struct perf_namespaces_event namespaces_event;
+	struct perf_ns_link_info *ns_link_info;
+
+	if (!atomic_read(&nr_namespaces_events))
+		return;
+
+	namespaces_event = (struct perf_namespaces_event){
+		.task	= task,
+		.event_id  = {
+			.header = {
+				.type = PERF_RECORD_NAMESPACES,
+				.misc = 0,
+				.size = sizeof(namespaces_event.event_id),
+			},
+			/* .pid */
+			/* .tid */
+			.nr_namespaces = NR_NAMESPACES,
+			/* .link_info[NR_NAMESPACES] */
+		},
+	};
+
+	ns_link_info = namespaces_event.event_id.link_info;
+
+	perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
+			       task, &mntns_operations);
+
+#ifdef CONFIG_USER_NS
+	perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
+			       task, &userns_operations);
+#endif
+#ifdef CONFIG_NET_NS
+	perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
+			       task, &netns_operations);
+#endif
+#ifdef CONFIG_UTS_NS
+	perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
+			       task, &utsns_operations);
+#endif
+#ifdef CONFIG_IPC_NS
+	perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
+			       task, &ipcns_operations);
+#endif
+#ifdef CONFIG_PID_NS
+	perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
+			       task, &pidns_operations);
+#endif
+#ifdef CONFIG_CGROUPS
+	perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
+			       task, &cgroupns_operations);
+#endif
+
+	perf_iterate_sb(perf_event_namespaces_output,
+			&namespaces_event,
+			NULL);
+}
+
+/*
+ * cgroup tracking
+ */
+#ifdef CONFIG_CGROUP_PERF
+
+struct perf_cgroup_event {
+	char				*path;
+	int				path_size;
+	struct {
+		struct perf_event_header	header;
+		u64				id;
+		char				path[];
+	} event_id;
+};
+
+static int perf_event_cgroup_match(struct perf_event *event)
+{
+	return event->attr.cgroup;
+}
+
+static void perf_event_cgroup_output(struct perf_event *event, void *data)
+{
+	struct perf_cgroup_event *cgroup_event = data;
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	u16 header_size = cgroup_event->event_id.header.size;
+	int ret;
+
+	if (!perf_event_cgroup_match(event))
+		return;
+
+	perf_event_header__init_id(&cgroup_event->event_id.header,
+				   &sample, event);
+	ret = perf_output_begin(&handle, &sample, event,
+				cgroup_event->event_id.header.size);
+	if (ret)
+		goto out;
+
+	perf_output_put(&handle, cgroup_event->event_id);
+	__output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
+
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+out:
+	cgroup_event->event_id.header.size = header_size;
+}
+
+static void perf_event_cgroup(struct cgroup *cgrp)
+{
+	struct perf_cgroup_event cgroup_event;
+	char path_enomem[16] = "//enomem";
+	char *pathname;
+	size_t size;
+
+	if (!atomic_read(&nr_cgroup_events))
+		return;
+
+	cgroup_event = (struct perf_cgroup_event){
+		.event_id  = {
+			.header = {
+				.type = PERF_RECORD_CGROUP,
+				.misc = 0,
+				.size = sizeof(cgroup_event.event_id),
+			},
+			.id = cgroup_id(cgrp),
+		},
+	};
+
+	pathname = kmalloc(PATH_MAX, GFP_KERNEL);
+	if (pathname == NULL) {
+		cgroup_event.path = path_enomem;
+	} else {
+		/* just to be sure to have enough space for alignment */
+		cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
+		cgroup_event.path = pathname;
+	}
+
+	/*
+	 * Since our buffer works in 8 byte units we need to align our string
+	 * size to a multiple of 8. However, we must guarantee the tail end is
+	 * zero'd out to avoid leaking random bits to userspace.
+	 */
+	size = strlen(cgroup_event.path) + 1;
+	while (!IS_ALIGNED(size, sizeof(u64)))
+		cgroup_event.path[size++] = '\0';
+
+	cgroup_event.event_id.header.size += size;
+	cgroup_event.path_size = size;
+
+	perf_iterate_sb(perf_event_cgroup_output,
+			&cgroup_event,
+			NULL);
+
+	kfree(pathname);
+}
+
+#endif
+
+/*
+ * mmap tracking
+ */
+
+struct perf_mmap_event {
+	struct vm_area_struct	*vma;
+
+	const char		*file_name;
+	int			file_size;
+	int			maj, min;
+	u64			ino;
+	u64			ino_generation;
+	u32			prot, flags;
+	u8			build_id[BUILD_ID_SIZE_MAX];
+	u32			build_id_size;
+
+	struct {
+		struct perf_event_header	header;
+
+		u32				pid;
+		u32				tid;
+		u64				start;
+		u64				len;
+		u64				pgoff;
+	} event_id;
+};
+
+static int perf_event_mmap_match(struct perf_event *event,
+				 void *data)
+{
+	struct perf_mmap_event *mmap_event = data;
+	struct vm_area_struct *vma = mmap_event->vma;
+	int executable = vma->vm_flags & VM_EXEC;
+
+	return (!executable && event->attr.mmap_data) ||
+	       (executable && (event->attr.mmap || event->attr.mmap2));
+}
+
+static void perf_event_mmap_output(struct perf_event *event,
+				   void *data)
+{
+	struct perf_mmap_event *mmap_event = data;
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	int size = mmap_event->event_id.header.size;
+	u32 type = mmap_event->event_id.header.type;
+	bool use_build_id;
+	int ret;
+
+	if (!perf_event_mmap_match(event, data))
+		return;
+
+	if (event->attr.mmap2) {
+		mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
+		mmap_event->event_id.header.size += sizeof(mmap_event->maj);
+		mmap_event->event_id.header.size += sizeof(mmap_event->min);
+		mmap_event->event_id.header.size += sizeof(mmap_event->ino);
+		mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
+		mmap_event->event_id.header.size += sizeof(mmap_event->prot);
+		mmap_event->event_id.header.size += sizeof(mmap_event->flags);
+	}
+
+	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
+	ret = perf_output_begin(&handle, &sample, event,
+				mmap_event->event_id.header.size);
+	if (ret)
+		goto out;
+
+	mmap_event->event_id.pid = perf_event_pid(event, current);
+	mmap_event->event_id.tid = perf_event_tid(event, current);
+
+	use_build_id = event->attr.build_id && mmap_event->build_id_size;
+
+	if (event->attr.mmap2 && use_build_id)
+		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
+
+	perf_output_put(&handle, mmap_event->event_id);
+
+	if (event->attr.mmap2) {
+		if (use_build_id) {
+			u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
+
+			__output_copy(&handle, size, 4);
+			__output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
+		} else {
+			perf_output_put(&handle, mmap_event->maj);
+			perf_output_put(&handle, mmap_event->min);
+			perf_output_put(&handle, mmap_event->ino);
+			perf_output_put(&handle, mmap_event->ino_generation);
+		}
+		perf_output_put(&handle, mmap_event->prot);
+		perf_output_put(&handle, mmap_event->flags);
+	}
+
+	__output_copy(&handle, mmap_event->file_name,
+				   mmap_event->file_size);
+
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+out:
+	mmap_event->event_id.header.size = size;
+	mmap_event->event_id.header.type = type;
+}
+
+static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
+{
+	struct vm_area_struct *vma = mmap_event->vma;
+	struct file *file = vma->vm_file;
+	int maj = 0, min = 0;
+	u64 ino = 0, gen = 0;
+	u32 prot = 0, flags = 0;
+	unsigned int size;
+	char tmp[16];
+	char *buf = NULL;
+	char *name;
+
+	if (vma->vm_flags & VM_READ)
+		prot |= PROT_READ;
+	if (vma->vm_flags & VM_WRITE)
+		prot |= PROT_WRITE;
+	if (vma->vm_flags & VM_EXEC)
+		prot |= PROT_EXEC;
+
+	if (vma->vm_flags & VM_MAYSHARE)
+		flags = MAP_SHARED;
+	else
+		flags = MAP_PRIVATE;
+
+	if (vma->vm_flags & VM_LOCKED)
+		flags |= MAP_LOCKED;
+	if (is_vm_hugetlb_page(vma))
+		flags |= MAP_HUGETLB;
+
+	if (file) {
+		struct inode *inode;
+		dev_t dev;
+
+		buf = kmalloc(PATH_MAX, GFP_KERNEL);
+		if (!buf) {
+			name = "//enomem";
+			goto cpy_name;
+		}
+		/*
+		 * d_path() works from the end of the rb backwards, so we
+		 * need to add enough zero bytes after the string to handle
+		 * the 64bit alignment we do later.
+		 */
+		name = file_path(file, buf, PATH_MAX - sizeof(u64));
+		if (IS_ERR(name)) {
+			name = "//toolong";
+			goto cpy_name;
+		}
+		inode = file_inode(vma->vm_file);
+		dev = inode->i_sb->s_dev;
+		ino = inode->i_ino;
+		gen = inode->i_generation;
+		maj = MAJOR(dev);
+		min = MINOR(dev);
+
+		goto got_name;
+	} else {
+		if (vma->vm_ops && vma->vm_ops->name) {
+			name = (char *) vma->vm_ops->name(vma);
+			if (name)
+				goto cpy_name;
+		}
+
+		name = (char *)arch_vma_name(vma);
+		if (name)
+			goto cpy_name;
+
+		if (vma->vm_start <= vma->vm_mm->start_brk &&
+				vma->vm_end >= vma->vm_mm->brk) {
+			name = "[heap]";
+			goto cpy_name;
+		}
+		if (vma->vm_start <= vma->vm_mm->start_stack &&
+				vma->vm_end >= vma->vm_mm->start_stack) {
+			name = "[stack]";
+			goto cpy_name;
+		}
+
+		name = "//anon";
+		goto cpy_name;
+	}
+
+cpy_name:
+	strlcpy(tmp, name, sizeof(tmp));
+	name = tmp;
+got_name:
+	/*
+	 * Since our buffer works in 8 byte units we need to align our string
+	 * size to a multiple of 8. However, we must guarantee the tail end is
+	 * zero'd out to avoid leaking random bits to userspace.
+	 */
+	size = strlen(name)+1;
+	while (!IS_ALIGNED(size, sizeof(u64)))
+		name[size++] = '\0';
+
+	mmap_event->file_name = name;
+	mmap_event->file_size = size;
+	mmap_event->maj = maj;
+	mmap_event->min = min;
+	mmap_event->ino = ino;
+	mmap_event->ino_generation = gen;
+	mmap_event->prot = prot;
+	mmap_event->flags = flags;
+
+	if (!(vma->vm_flags & VM_EXEC))
+		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
+
+	mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
+
+	if (atomic_read(&nr_build_id_events))
+		build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
+
+	perf_iterate_sb(perf_event_mmap_output,
+		       mmap_event,
+		       NULL);
+
+	kfree(buf);
+}
+
+/*
+ * Check whether inode and address range match filter criteria.
+ */
+static bool perf_addr_filter_match(struct perf_addr_filter *filter,
+				     struct file *file, unsigned long offset,
+				     unsigned long size)
+{
+	/* d_inode(NULL) won't be equal to any mapped user-space file */
+	if (!filter->path.dentry)
+		return false;
+
+	if (d_inode(filter->path.dentry) != file_inode(file))
+		return false;
+
+	if (filter->offset > offset + size)
+		return false;
+
+	if (filter->offset + filter->size < offset)
+		return false;
+
+	return true;
+}
+
+static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
+					struct vm_area_struct *vma,
+					struct perf_addr_filter_range *fr)
+{
+	unsigned long vma_size = vma->vm_end - vma->vm_start;
+	unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
+	struct file *file = vma->vm_file;
+
+	if (!perf_addr_filter_match(filter, file, off, vma_size))
+		return false;
+
+	if (filter->offset < off) {
+		fr->start = vma->vm_start;
+		fr->size = min(vma_size, filter->size - (off - filter->offset));
+	} else {
+		fr->start = vma->vm_start + filter->offset - off;
+		fr->size = min(vma->vm_end - fr->start, filter->size);
+	}
+
+	return true;
+}
+
+static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
+{
+	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
+	struct vm_area_struct *vma = data;
+	struct perf_addr_filter *filter;
+	unsigned int restart = 0, count = 0;
+	unsigned long flags;
+
+	if (!has_addr_filter(event))
+		return;
+
+	if (!vma->vm_file)
+		return;
+
+	raw_spin_lock_irqsave(&ifh->lock, flags);
+	list_for_each_entry(filter, &ifh->list, entry) {
+		if (perf_addr_filter_vma_adjust(filter, vma,
+						&event->addr_filter_ranges[count]))
+			restart++;
+
+		count++;
+	}
+
+	if (restart)
+		event->addr_filters_gen++;
+	raw_spin_unlock_irqrestore(&ifh->lock, flags);
+
+	if (restart)
+		perf_event_stop(event, 1);
+}
+
+/*
+ * Adjust all task's events' filters to the new vma
+ */
+static void perf_addr_filters_adjust(struct vm_area_struct *vma)
+{
+	struct perf_event_context *ctx;
+	int ctxn;
+
+	/*
+	 * Data tracing isn't supported yet and as such there is no need
+	 * to keep track of anything that isn't related to executable code:
+	 */
+	if (!(vma->vm_flags & VM_EXEC))
+		return;
+
+	rcu_read_lock();
+	for_each_task_context_nr(ctxn) {
+		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
+		if (!ctx)
+			continue;
+
+		perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
+	}
+	rcu_read_unlock();
+}
+
+void perf_event_mmap(struct vm_area_struct *vma)
+{
+	struct perf_mmap_event mmap_event;
+
+	if (!atomic_read(&nr_mmap_events))
+		return;
+
+	mmap_event = (struct perf_mmap_event){
+		.vma	= vma,
+		/* .file_name */
+		/* .file_size */
+		.event_id  = {
+			.header = {
+				.type = PERF_RECORD_MMAP,
+				.misc = PERF_RECORD_MISC_USER,
+				/* .size */
+			},
+			/* .pid */
+			/* .tid */
+			.start  = vma->vm_start,
+			.len    = vma->vm_end - vma->vm_start,
+			.pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
+		},
+		/* .maj (attr_mmap2 only) */
+		/* .min (attr_mmap2 only) */
+		/* .ino (attr_mmap2 only) */
+		/* .ino_generation (attr_mmap2 only) */
+		/* .prot (attr_mmap2 only) */
+		/* .flags (attr_mmap2 only) */
+	};
+
+	perf_addr_filters_adjust(vma);
+	perf_event_mmap_event(&mmap_event);
+}
+
+void perf_event_aux_event(struct perf_event *event, unsigned long head,
+			  unsigned long size, u64 flags)
+{
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	struct perf_aux_event {
+		struct perf_event_header	header;
+		u64				offset;
+		u64				size;
+		u64				flags;
+	} rec = {
+		.header = {
+			.type = PERF_RECORD_AUX,
+			.misc = 0,
+			.size = sizeof(rec),
+		},
+		.offset		= head,
+		.size		= size,
+		.flags		= flags,
+	};
+	int ret;
+
+	perf_event_header__init_id(&rec.header, &sample, event);
+	ret = perf_output_begin(&handle, &sample, event, rec.header.size);
+
+	if (ret)
+		return;
+
+	perf_output_put(&handle, rec);
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+}
+
+/*
+ * Lost/dropped samples logging
+ */
+void perf_log_lost_samples(struct perf_event *event, u64 lost)
+{
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	int ret;
+
+	struct {
+		struct perf_event_header	header;
+		u64				lost;
+	} lost_samples_event = {
+		.header = {
+			.type = PERF_RECORD_LOST_SAMPLES,
+			.misc = 0,
+			.size = sizeof(lost_samples_event),
+		},
+		.lost		= lost,
+	};
+
+	perf_event_header__init_id(&lost_samples_event.header, &sample, event);
+
+	ret = perf_output_begin(&handle, &sample, event,
+				lost_samples_event.header.size);
+	if (ret)
+		return;
+
+	perf_output_put(&handle, lost_samples_event);
+	perf_event__output_id_sample(event, &handle, &sample);
+	perf_output_end(&handle);
+}
+
+/*
+ * context_switch tracking
+ */
+
+struct perf_switch_event {
+	struct task_struct	*task;
+	struct task_struct	*next_prev;
+
+	struct {
+		struct perf_event_header	header;
+		u32				next_prev_pid;
+		u32				next_prev_tid;
+	} event_id;
+};
+
+static int perf_event_switch_match(struct perf_event *event)
+{
+	return event->attr.context_switch;
+}
+
+static void perf_event_switch_output(struct perf_event *event, void *data)
+{
+	struct perf_switch_event *se = data;
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	int ret;
+
+	if (!perf_event_switch_match(event))
+		return;
+
+	/* Only CPU-wide events are allowed to see next/prev pid/tid */
+	if (event->ctx->task) {
+		se->event_id.header.type = PERF_RECORD_SWITCH;
+		se->event_id.header.size = sizeof(se->event_id.header);
+	} else {
+		se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
+		se->event_id.header.size = sizeof(se->event_id);
+		se->event_id.next_prev_pid =
+					perf_event_pid(event, se->next_prev);
+		se->event_id.next_prev_tid =
+					perf_event_tid(event, se->next_prev);
+	}
+
+	perf_event_header__init_id(&se->event_id.header, &sample, event);
+
+	ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
+	if (ret)
+		return;
+
+	if (event->ctx->task)
+		perf_output_put(&handle, se->event_id.header);
+	else
+		perf_output_put(&handle, se->event_id);
+
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+}
+
+static void perf_event_switch(struct task_struct *task,
+			      struct task_struct *next_prev, bool sched_in)
+{
+	struct perf_switch_event switch_event;
+
+	/* N.B. caller checks nr_switch_events != 0 */
+
+	switch_event = (struct perf_switch_event){
+		.task		= task,
+		.next_prev	= next_prev,
+		.event_id	= {
+			.header = {
+				/* .type */
+				.misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
+				/* .size */
+			},
+			/* .next_prev_pid */
+			/* .next_prev_tid */
+		},
+	};
+
+	if (!sched_in && task->on_rq) {
+		switch_event.event_id.header.misc |=
+				PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
+	}
+
+	perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
+}
+
+/*
+ * IRQ throttle logging
+ */
+
+static void perf_log_throttle(struct perf_event *event, int enable)
+{
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	int ret;
+
+	struct {
+		struct perf_event_header	header;
+		u64				time;
+		u64				id;
+		u64				stream_id;
+	} throttle_event = {
+		.header = {
+			.type = PERF_RECORD_THROTTLE,
+			.misc = 0,
+			.size = sizeof(throttle_event),
+		},
+		.time		= perf_event_clock(event),
+		.id		= primary_event_id(event),
+		.stream_id	= event->id,
+	};
+
+	if (enable)
+		throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
+
+	perf_event_header__init_id(&throttle_event.header, &sample, event);
+
+	ret = perf_output_begin(&handle, &sample, event,
+				throttle_event.header.size);
+	if (ret)
+		return;
+
+	perf_output_put(&handle, throttle_event);
+	perf_event__output_id_sample(event, &handle, &sample);
+	perf_output_end(&handle);
+}
+
+/*
+ * ksymbol register/unregister tracking
+ */
+
+struct perf_ksymbol_event {
+	const char	*name;
+	int		name_len;
+	struct {
+		struct perf_event_header        header;
+		u64				addr;
+		u32				len;
+		u16				ksym_type;
+		u16				flags;
+	} event_id;
+};
+
+static int perf_event_ksymbol_match(struct perf_event *event)
+{
+	return event->attr.ksymbol;
+}
+
+static void perf_event_ksymbol_output(struct perf_event *event, void *data)
+{
+	struct perf_ksymbol_event *ksymbol_event = data;
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	int ret;
+
+	if (!perf_event_ksymbol_match(event))
+		return;
+
+	perf_event_header__init_id(&ksymbol_event->event_id.header,
+				   &sample, event);
+	ret = perf_output_begin(&handle, &sample, event,
+				ksymbol_event->event_id.header.size);
+	if (ret)
+		return;
+
+	perf_output_put(&handle, ksymbol_event->event_id);
+	__output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+}
+
+void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
+			const char *sym)
+{
+	struct perf_ksymbol_event ksymbol_event;
+	char name[KSYM_NAME_LEN];
+	u16 flags = 0;
+	int name_len;
+
+	if (!atomic_read(&nr_ksymbol_events))
+		return;
+
+	if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
+	    ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
+		goto err;
+
+	strlcpy(name, sym, KSYM_NAME_LEN);
+	name_len = strlen(name) + 1;
+	while (!IS_ALIGNED(name_len, sizeof(u64)))
+		name[name_len++] = '\0';
+	BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
+
+	if (unregister)
+		flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
+
+	ksymbol_event = (struct perf_ksymbol_event){
+		.name = name,
+		.name_len = name_len,
+		.event_id = {
+			.header = {
+				.type = PERF_RECORD_KSYMBOL,
+				.size = sizeof(ksymbol_event.event_id) +
+					name_len,
+			},
+			.addr = addr,
+			.len = len,
+			.ksym_type = ksym_type,
+			.flags = flags,
+		},
+	};
+
+	perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
+	return;
+err:
+	WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
+}
+
+/*
+ * bpf program load/unload tracking
+ */
+
+struct perf_bpf_event {
+	struct bpf_prog	*prog;
+	struct {
+		struct perf_event_header        header;
+		u16				type;
+		u16				flags;
+		u32				id;
+		u8				tag[BPF_TAG_SIZE];
+	} event_id;
+};
+
+static int perf_event_bpf_match(struct perf_event *event)
+{
+	return event->attr.bpf_event;
+}
+
+static void perf_event_bpf_output(struct perf_event *event, void *data)
+{
+	struct perf_bpf_event *bpf_event = data;
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	int ret;
+
+	if (!perf_event_bpf_match(event))
+		return;
+
+	perf_event_header__init_id(&bpf_event->event_id.header,
+				   &sample, event);
+	ret = perf_output_begin(&handle, &sample, event,
+				bpf_event->event_id.header.size);
+	if (ret)
+		return;
+
+	perf_output_put(&handle, bpf_event->event_id);
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+}
+
+static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
+					 enum perf_bpf_event_type type)
+{
+	bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
+	int i;
+
+	if (prog->aux->func_cnt == 0) {
+		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
+				   (u64)(unsigned long)prog->bpf_func,
+				   prog->jited_len, unregister,
+				   prog->aux->ksym.name);
+	} else {
+		for (i = 0; i < prog->aux->func_cnt; i++) {
+			struct bpf_prog *subprog = prog->aux->func[i];
+
+			perf_event_ksymbol(
+				PERF_RECORD_KSYMBOL_TYPE_BPF,
+				(u64)(unsigned long)subprog->bpf_func,
+				subprog->jited_len, unregister,
+				subprog->aux->ksym.name);
+		}
+	}
+}
+
+void perf_event_bpf_event(struct bpf_prog *prog,
+			  enum perf_bpf_event_type type,
+			  u16 flags)
+{
+	struct perf_bpf_event bpf_event;
+
+	if (type <= PERF_BPF_EVENT_UNKNOWN ||
+	    type >= PERF_BPF_EVENT_MAX)
+		return;
+
+	switch (type) {
+	case PERF_BPF_EVENT_PROG_LOAD:
+	case PERF_BPF_EVENT_PROG_UNLOAD:
+		if (atomic_read(&nr_ksymbol_events))
+			perf_event_bpf_emit_ksymbols(prog, type);
+		break;
+	default:
+		break;
+	}
+
+	if (!atomic_read(&nr_bpf_events))
+		return;
+
+	bpf_event = (struct perf_bpf_event){
+		.prog = prog,
+		.event_id = {
+			.header = {
+				.type = PERF_RECORD_BPF_EVENT,
+				.size = sizeof(bpf_event.event_id),
+			},
+			.type = type,
+			.flags = flags,
+			.id = prog->aux->id,
+		},
+	};
+
+	BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
+
+	memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
+	perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
+}
+
+struct perf_text_poke_event {
+	const void		*old_bytes;
+	const void		*new_bytes;
+	size_t			pad;
+	u16			old_len;
+	u16			new_len;
+
+	struct {
+		struct perf_event_header	header;
+
+		u64				addr;
+	} event_id;
+};
+
+static int perf_event_text_poke_match(struct perf_event *event)
+{
+	return event->attr.text_poke;
+}
+
+static void perf_event_text_poke_output(struct perf_event *event, void *data)
+{
+	struct perf_text_poke_event *text_poke_event = data;
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	u64 padding = 0;
+	int ret;
+
+	if (!perf_event_text_poke_match(event))
+		return;
+
+	perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
+
+	ret = perf_output_begin(&handle, &sample, event,
+				text_poke_event->event_id.header.size);
+	if (ret)
+		return;
+
+	perf_output_put(&handle, text_poke_event->event_id);
+	perf_output_put(&handle, text_poke_event->old_len);
+	perf_output_put(&handle, text_poke_event->new_len);
+
+	__output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
+	__output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
+
+	if (text_poke_event->pad)
+		__output_copy(&handle, &padding, text_poke_event->pad);
+
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+}
+
+void perf_event_text_poke(const void *addr, const void *old_bytes,
+			  size_t old_len, const void *new_bytes, size_t new_len)
+{
+	struct perf_text_poke_event text_poke_event;
+	size_t tot, pad;
+
+	if (!atomic_read(&nr_text_poke_events))
+		return;
+
+	tot  = sizeof(text_poke_event.old_len) + old_len;
+	tot += sizeof(text_poke_event.new_len) + new_len;
+	pad  = ALIGN(tot, sizeof(u64)) - tot;
+
+	text_poke_event = (struct perf_text_poke_event){
+		.old_bytes    = old_bytes,
+		.new_bytes    = new_bytes,
+		.pad          = pad,
+		.old_len      = old_len,
+		.new_len      = new_len,
+		.event_id  = {
+			.header = {
+				.type = PERF_RECORD_TEXT_POKE,
+				.misc = PERF_RECORD_MISC_KERNEL,
+				.size = sizeof(text_poke_event.event_id) + tot + pad,
+			},
+			.addr = (unsigned long)addr,
+		},
+	};
+
+	perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
+}
+
+void perf_event_itrace_started(struct perf_event *event)
+{
+	event->attach_state |= PERF_ATTACH_ITRACE;
+}
+
+static void perf_log_itrace_start(struct perf_event *event)
+{
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	struct perf_aux_event {
+		struct perf_event_header        header;
+		u32				pid;
+		u32				tid;
+	} rec;
+	int ret;
+
+	if (event->parent)
+		event = event->parent;
+
+	if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
+	    event->attach_state & PERF_ATTACH_ITRACE)
+		return;
+
+	rec.header.type	= PERF_RECORD_ITRACE_START;
+	rec.header.misc	= 0;
+	rec.header.size	= sizeof(rec);
+	rec.pid	= perf_event_pid(event, current);
+	rec.tid	= perf_event_tid(event, current);
+
+	perf_event_header__init_id(&rec.header, &sample, event);
+	ret = perf_output_begin(&handle, &sample, event, rec.header.size);
+
+	if (ret)
+		return;
+
+	perf_output_put(&handle, rec);
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+}
+
+void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
+{
+	struct perf_output_handle handle;
+	struct perf_sample_data sample;
+	struct perf_aux_event {
+		struct perf_event_header        header;
+		u64				hw_id;
+	} rec;
+	int ret;
+
+	if (event->parent)
+		event = event->parent;
+
+	rec.header.type	= PERF_RECORD_AUX_OUTPUT_HW_ID;
+	rec.header.misc	= 0;
+	rec.header.size	= sizeof(rec);
+	rec.hw_id	= hw_id;
+
+	perf_event_header__init_id(&rec.header, &sample, event);
+	ret = perf_output_begin(&handle, &sample, event, rec.header.size);
+
+	if (ret)
+		return;
+
+	perf_output_put(&handle, rec);
+	perf_event__output_id_sample(event, &handle, &sample);
+
+	perf_output_end(&handle);
+}
+
+static int
+__perf_event_account_interrupt(struct perf_event *event, int throttle)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	int ret = 0;
+	u64 seq;
+
+	seq = __this_cpu_read(perf_throttled_seq);
+	if (seq != hwc->interrupts_seq) {
+		hwc->interrupts_seq = seq;
+		hwc->interrupts = 1;
+	} else {
+		hwc->interrupts++;
+		if (unlikely(throttle &&
+			     hwc->interrupts > max_samples_per_tick)) {
+			__this_cpu_inc(perf_throttled_count);
+			tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
+			hwc->interrupts = MAX_INTERRUPTS;
+			perf_log_throttle(event, 0);
+			ret = 1;
+		}
+	}
+
+	if (event->attr.freq) {
+		u64 now = perf_clock();
+		s64 delta = now - hwc->freq_time_stamp;
+
+		hwc->freq_time_stamp = now;
+
+		if (delta > 0 && delta < 2*TICK_NSEC)
+			perf_adjust_period(event, delta, hwc->last_period, true);
+	}
+
+	return ret;
+}
+
+int perf_event_account_interrupt(struct perf_event *event)
+{
+	return __perf_event_account_interrupt(event, 1);
+}
+
+static inline bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs)
+{
+	/*
+	 * Due to interrupt latency (AKA "skid"), we may enter the
+	 * kernel before taking an overflow, even if the PMU is only
+	 * counting user events.
+	 */
+	if (event->attr.exclude_kernel && !user_mode(regs))
+		return false;
+
+	return true;
+}
+
+/*
+ * Generic event overflow handling, sampling.
+ */
+
+static int __perf_event_overflow(struct perf_event *event,
+				 int throttle, struct perf_sample_data *data,
+				 struct pt_regs *regs)
+{
+	int events = atomic_read(&event->event_limit);
+	int ret = 0;
+
+	/*
+	 * Non-sampling counters might still use the PMI to fold short
+	 * hardware counters, ignore those.
+	 */
+	if (unlikely(!is_sampling_event(event)))
+		return 0;
+
+	ret = __perf_event_account_interrupt(event, throttle);
+
+	/*
+	 * XXX event_limit might not quite work as expected on inherited
+	 * events
+	 */
+
+	event->pending_kill = POLL_IN;
+	if (events && atomic_dec_and_test(&event->event_limit)) {
+		ret = 1;
+		event->pending_kill = POLL_HUP;
+		perf_event_disable_inatomic(event);
+	}
+
+	if (event->attr.sigtrap) {
+		/*
+		 * The desired behaviour of sigtrap vs invalid samples is a bit
+		 * tricky; on the one hand, one should not loose the SIGTRAP if
+		 * it is the first event, on the other hand, we should also not
+		 * trigger the WARN or override the data address.
+		 */
+		bool valid_sample = sample_is_allowed(event, regs);
+		unsigned int pending_id = 1;
+
+		if (regs)
+			pending_id = hash32_ptr((void *)instruction_pointer(regs)) ?: 1;
+		if (!event->pending_sigtrap) {
+			event->pending_sigtrap = pending_id;
+			local_inc(&event->ctx->nr_pending);
+		} else if (event->attr.exclude_kernel && valid_sample) {
+			/*
+			 * Should not be able to return to user space without
+			 * consuming pending_sigtrap; with exceptions:
+			 *
+			 *  1. Where !exclude_kernel, events can overflow again
+			 *     in the kernel without returning to user space.
+			 *
+			 *  2. Events that can overflow again before the IRQ-
+			 *     work without user space progress (e.g. hrtimer).
+			 *     To approximate progress (with false negatives),
+			 *     check 32-bit hash of the current IP.
+			 */
+			WARN_ON_ONCE(event->pending_sigtrap != pending_id);
+		}
+
+		event->pending_addr = 0;
+		if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR))
+			event->pending_addr = data->addr;
+		irq_work_queue(&event->pending_irq);
+	}
+
+	READ_ONCE(event->overflow_handler)(event, data, regs);
+
+	if (*perf_event_fasync(event) && event->pending_kill) {
+		event->pending_wakeup = 1;
+		irq_work_queue(&event->pending_irq);
+	}
+
+	return ret;
+}
+
+int perf_event_overflow(struct perf_event *event,
+			struct perf_sample_data *data,
+			struct pt_regs *regs)
+{
+	return __perf_event_overflow(event, 1, data, regs);
+}
+
+/*
+ * Generic software event infrastructure
+ */
+
+struct swevent_htable {
+	struct swevent_hlist		*swevent_hlist;
+	struct mutex			hlist_mutex;
+	int				hlist_refcount;
+
+	/* Recursion avoidance in each contexts */
+	int				recursion[PERF_NR_CONTEXTS];
+};
+
+static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
+
+/*
+ * We directly increment event->count and keep a second value in
+ * event->hw.period_left to count intervals. This period event
+ * is kept in the range [-sample_period, 0] so that we can use the
+ * sign as trigger.
+ */
+
+u64 perf_swevent_set_period(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	u64 period = hwc->last_period;
+	u64 nr, offset;
+	s64 old, val;
+
+	hwc->last_period = hwc->sample_period;
+
+again:
+	old = val = local64_read(&hwc->period_left);
+	if (val < 0)
+		return 0;
+
+	nr = div64_u64(period + val, period);
+	offset = nr * period;
+	val -= offset;
+	if (local64_cmpxchg(&hwc->period_left, old, val) != old)
+		goto again;
+
+	return nr;
+}
+
+static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
+				    struct perf_sample_data *data,
+				    struct pt_regs *regs)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	int throttle = 0;
+
+	if (!overflow)
+		overflow = perf_swevent_set_period(event);
+
+	if (hwc->interrupts == MAX_INTERRUPTS)
+		return;
+
+	for (; overflow; overflow--) {
+		if (__perf_event_overflow(event, throttle,
+					    data, regs)) {
+			/*
+			 * We inhibit the overflow from happening when
+			 * hwc->interrupts == MAX_INTERRUPTS.
+			 */
+			break;
+		}
+		throttle = 1;
+	}
+}
+
+static void perf_swevent_event(struct perf_event *event, u64 nr,
+			       struct perf_sample_data *data,
+			       struct pt_regs *regs)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	local64_add(nr, &event->count);
+
+	if (!regs)
+		return;
+
+	if (!is_sampling_event(event))
+		return;
+
+	if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
+		data->period = nr;
+		return perf_swevent_overflow(event, 1, data, regs);
+	} else
+		data->period = event->hw.last_period;
+
+	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
+		return perf_swevent_overflow(event, 1, data, regs);
+
+	if (local64_add_negative(nr, &hwc->period_left))
+		return;
+
+	perf_swevent_overflow(event, 0, data, regs);
+}
+
+static int perf_exclude_event(struct perf_event *event,
+			      struct pt_regs *regs)
+{
+	if (event->hw.state & PERF_HES_STOPPED)
+		return 1;
+
+	if (regs) {
+		if (event->attr.exclude_user && user_mode(regs))
+			return 1;
+
+		if (event->attr.exclude_kernel && !user_mode(regs))
+			return 1;
+	}
+
+	return 0;
+}
+
+static int perf_swevent_match(struct perf_event *event,
+				enum perf_type_id type,
+				u32 event_id,
+				struct perf_sample_data *data,
+				struct pt_regs *regs)
+{
+	if (event->attr.type != type)
+		return 0;
+
+	if (event->attr.config != event_id)
+		return 0;
+
+	if (perf_exclude_event(event, regs))
+		return 0;
+
+	return 1;
+}
+
+static inline u64 swevent_hash(u64 type, u32 event_id)
+{
+	u64 val = event_id | (type << 32);
+
+	return hash_64(val, SWEVENT_HLIST_BITS);
+}
+
+static inline struct hlist_head *
+__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
+{
+	u64 hash = swevent_hash(type, event_id);
+
+	return &hlist->heads[hash];
+}
+
+/* For the read side: events when they trigger */
+static inline struct hlist_head *
+find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
+{
+	struct swevent_hlist *hlist;
+
+	hlist = rcu_dereference(swhash->swevent_hlist);
+	if (!hlist)
+		return NULL;
+
+	return __find_swevent_head(hlist, type, event_id);
+}
+
+/* For the event head insertion and removal in the hlist */
+static inline struct hlist_head *
+find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
+{
+	struct swevent_hlist *hlist;
+	u32 event_id = event->attr.config;
+	u64 type = event->attr.type;
+
+	/*
+	 * Event scheduling is always serialized against hlist allocation
+	 * and release. Which makes the protected version suitable here.
+	 * The context lock guarantees that.
+	 */
+	hlist = rcu_dereference_protected(swhash->swevent_hlist,
+					  lockdep_is_held(&event->ctx->lock));
+	if (!hlist)
+		return NULL;
+
+	return __find_swevent_head(hlist, type, event_id);
+}
+
+static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
+				    u64 nr,
+				    struct perf_sample_data *data,
+				    struct pt_regs *regs)
+{
+	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
+	struct perf_event *event;
+	struct hlist_head *head;
+
+	rcu_read_lock();
+	head = find_swevent_head_rcu(swhash, type, event_id);
+	if (!head)
+		goto end;
+
+	hlist_for_each_entry_rcu(event, head, hlist_entry) {
+		if (perf_swevent_match(event, type, event_id, data, regs))
+			perf_swevent_event(event, nr, data, regs);
+	}
+end:
+	rcu_read_unlock();
+}
+
+DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
+
+int perf_swevent_get_recursion_context(void)
+{
+	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
+
+	return get_recursion_context(swhash->recursion);
+}
+EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
+
+void perf_swevent_put_recursion_context(int rctx)
+{
+	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
+
+	put_recursion_context(swhash->recursion, rctx);
+}
+
+void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
+{
+	struct perf_sample_data data;
+
+	if (WARN_ON_ONCE(!regs))
+		return;
+
+	perf_sample_data_init(&data, addr, 0);
+	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
+}
+
+void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
+{
+	int rctx;
+
+	preempt_disable_notrace();
+	rctx = perf_swevent_get_recursion_context();
+	if (unlikely(rctx < 0))
+		goto fail;
+
+	___perf_sw_event(event_id, nr, regs, addr);
+
+	perf_swevent_put_recursion_context(rctx);
+fail:
+	preempt_enable_notrace();
+}
+
+static void perf_swevent_read(struct perf_event *event)
+{
+}
+
+static int perf_swevent_add(struct perf_event *event, int flags)
+{
+	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
+	struct hw_perf_event *hwc = &event->hw;
+	struct hlist_head *head;
+
+	if (is_sampling_event(event)) {
+		hwc->last_period = hwc->sample_period;
+		perf_swevent_set_period(event);
+	}
+
+	hwc->state = !(flags & PERF_EF_START);
+
+	head = find_swevent_head(swhash, event);
+	if (WARN_ON_ONCE(!head))
+		return -EINVAL;
+
+	hlist_add_head_rcu(&event->hlist_entry, head);
+	perf_event_update_userpage(event);
+
+	return 0;
+}
+
+static void perf_swevent_del(struct perf_event *event, int flags)
+{
+	hlist_del_rcu(&event->hlist_entry);
+}
+
+static void perf_swevent_start(struct perf_event *event, int flags)
+{
+	event->hw.state = 0;
+}
+
+static void perf_swevent_stop(struct perf_event *event, int flags)
+{
+	event->hw.state = PERF_HES_STOPPED;
+}
+
+/* Deref the hlist from the update side */
+static inline struct swevent_hlist *
+swevent_hlist_deref(struct swevent_htable *swhash)
+{
+	return rcu_dereference_protected(swhash->swevent_hlist,
+					 lockdep_is_held(&swhash->hlist_mutex));
+}
+
+static void swevent_hlist_release(struct swevent_htable *swhash)
+{
+	struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
+
+	if (!hlist)
+		return;
+
+	RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
+	kfree_rcu(hlist, rcu_head);
+}
+
+static void swevent_hlist_put_cpu(int cpu)
+{
+	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
+
+	mutex_lock(&swhash->hlist_mutex);
+
+	if (!--swhash->hlist_refcount)
+		swevent_hlist_release(swhash);
+
+	mutex_unlock(&swhash->hlist_mutex);
+}
+
+static void swevent_hlist_put(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		swevent_hlist_put_cpu(cpu);
+}
+
+static int swevent_hlist_get_cpu(int cpu)
+{
+	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
+	int err = 0;
+
+	mutex_lock(&swhash->hlist_mutex);
+	if (!swevent_hlist_deref(swhash) &&
+	    cpumask_test_cpu(cpu, perf_online_mask)) {
+		struct swevent_hlist *hlist;
+
+		hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
+		if (!hlist) {
+			err = -ENOMEM;
+			goto exit;
+		}
+		rcu_assign_pointer(swhash->swevent_hlist, hlist);
+	}
+	swhash->hlist_refcount++;
+exit:
+	mutex_unlock(&swhash->hlist_mutex);
+
+	return err;
+}
+
+static int swevent_hlist_get(void)
+{
+	int err, cpu, failed_cpu;
+
+	mutex_lock(&pmus_lock);
+	for_each_possible_cpu(cpu) {
+		err = swevent_hlist_get_cpu(cpu);
+		if (err) {
+			failed_cpu = cpu;
+			goto fail;
+		}
+	}
+	mutex_unlock(&pmus_lock);
+	return 0;
+fail:
+	for_each_possible_cpu(cpu) {
+		if (cpu == failed_cpu)
+			break;
+		swevent_hlist_put_cpu(cpu);
+	}
+	mutex_unlock(&pmus_lock);
+	return err;
+}
+
+struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
+
+static void sw_perf_event_destroy(struct perf_event *event)
+{
+	u64 event_id = event->attr.config;
+
+	WARN_ON(event->parent);
+
+	static_key_slow_dec(&perf_swevent_enabled[event_id]);
+	swevent_hlist_put();
+}
+
+static int perf_swevent_init(struct perf_event *event)
+{
+	u64 event_id = event->attr.config;
+
+	if (event->attr.type != PERF_TYPE_SOFTWARE)
+		return -ENOENT;
+
+	/*
+	 * no branch sampling for software events
+	 */
+	if (has_branch_stack(event))
+		return -EOPNOTSUPP;
+
+	switch (event_id) {
+	case PERF_COUNT_SW_CPU_CLOCK:
+	case PERF_COUNT_SW_TASK_CLOCK:
+		return -ENOENT;
+
+	default:
+		break;
+	}
+
+	if (event_id >= PERF_COUNT_SW_MAX)
+		return -ENOENT;
+
+	if (!event->parent) {
+		int err;
+
+		err = swevent_hlist_get();
+		if (err)
+			return err;
+
+		static_key_slow_inc(&perf_swevent_enabled[event_id]);
+		event->destroy = sw_perf_event_destroy;
+	}
+
+	return 0;
+}
+
+static struct pmu perf_swevent = {
+	.task_ctx_nr	= perf_sw_context,
+
+	.capabilities	= PERF_PMU_CAP_NO_NMI,
+
+	.event_init	= perf_swevent_init,
+	.add		= perf_swevent_add,
+	.del		= perf_swevent_del,
+	.start		= perf_swevent_start,
+	.stop		= perf_swevent_stop,
+	.read		= perf_swevent_read,
+};
+
+#ifdef CONFIG_EVENT_TRACING
+
+static int perf_tp_filter_match(struct perf_event *event,
+				struct perf_sample_data *data)
+{
+	void *record = data->raw->frag.data;
+
+	/* only top level events have filters set */
+	if (event->parent)
+		event = event->parent;
+
+	if (likely(!event->filter) || filter_match_preds(event->filter, record))
+		return 1;
+	return 0;
+}
+
+static int perf_tp_event_match(struct perf_event *event,
+				struct perf_sample_data *data,
+				struct pt_regs *regs)
+{
+	if (event->hw.state & PERF_HES_STOPPED)
+		return 0;
+	/*
+	 * If exclude_kernel, only trace user-space tracepoints (uprobes)
+	 */
+	if (event->attr.exclude_kernel && !user_mode(regs))
+		return 0;
+
+	if (!perf_tp_filter_match(event, data))
+		return 0;
+
+	return 1;
+}
+
+void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
+			       struct trace_event_call *call, u64 count,
+			       struct pt_regs *regs, struct hlist_head *head,
+			       struct task_struct *task)
+{
+	if (bpf_prog_array_valid(call)) {
+		*(struct pt_regs **)raw_data = regs;
+		if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
+			perf_swevent_put_recursion_context(rctx);
+			return;
+		}
+	}
+	perf_tp_event(call->event.type, count, raw_data, size, regs, head,
+		      rctx, task);
+}
+EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
+
+void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
+		   struct pt_regs *regs, struct hlist_head *head, int rctx,
+		   struct task_struct *task)
+{
+	struct perf_sample_data data;
+	struct perf_event *event;
+
+	struct perf_raw_record raw = {
+		.frag = {
+			.size = entry_size,
+			.data = record,
+		},
+	};
+
+	perf_sample_data_init(&data, 0, 0);
+	data.raw = &raw;
+	data.sample_flags |= PERF_SAMPLE_RAW;
+
+	perf_trace_buf_update(record, event_type);
+
+	hlist_for_each_entry_rcu(event, head, hlist_entry) {
+		if (perf_tp_event_match(event, &data, regs))
+			perf_swevent_event(event, count, &data, regs);
+	}
+
+	/*
+	 * If we got specified a target task, also iterate its context and
+	 * deliver this event there too.
+	 */
+	if (task && task != current) {
+		struct perf_event_context *ctx;
+		struct trace_entry *entry = record;
+
+		rcu_read_lock();
+		ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
+		if (!ctx)
+			goto unlock;
+
+		list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+			if (event->cpu != smp_processor_id())
+				continue;
+			if (event->attr.type != PERF_TYPE_TRACEPOINT)
+				continue;
+			if (event->attr.config != entry->type)
+				continue;
+			/* Cannot deliver synchronous signal to other task. */
+			if (event->attr.sigtrap)
+				continue;
+			if (perf_tp_event_match(event, &data, regs))
+				perf_swevent_event(event, count, &data, regs);
+		}
+unlock:
+		rcu_read_unlock();
+	}
+
+	perf_swevent_put_recursion_context(rctx);
+}
+EXPORT_SYMBOL_GPL(perf_tp_event);
+
+static void tp_perf_event_destroy(struct perf_event *event)
+{
+	perf_trace_destroy(event);
+}
+
+static int perf_tp_event_init(struct perf_event *event)
+{
+	int err;
+
+	if (event->attr.type != PERF_TYPE_TRACEPOINT)
+		return -ENOENT;
+
+	/*
+	 * no branch sampling for tracepoint events
+	 */
+	if (has_branch_stack(event))
+		return -EOPNOTSUPP;
+
+	err = perf_trace_init(event);
+	if (err)
+		return err;
+
+	event->destroy = tp_perf_event_destroy;
+
+	return 0;
+}
+
+static struct pmu perf_tracepoint = {
+	.task_ctx_nr	= perf_sw_context,
+
+	.event_init	= perf_tp_event_init,
+	.add		= perf_trace_add,
+	.del		= perf_trace_del,
+	.start		= perf_swevent_start,
+	.stop		= perf_swevent_stop,
+	.read		= perf_swevent_read,
+};
+
+#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
+/*
+ * Flags in config, used by dynamic PMU kprobe and uprobe
+ * The flags should match following PMU_FORMAT_ATTR().
+ *
+ * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
+ *                               if not set, create kprobe/uprobe
+ *
+ * The following values specify a reference counter (or semaphore in the
+ * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
+ * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
+ *
+ * PERF_UPROBE_REF_CTR_OFFSET_BITS	# of bits in config as th offset
+ * PERF_UPROBE_REF_CTR_OFFSET_SHIFT	# of bits to shift left
+ */
+enum perf_probe_config {
+	PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0,  /* [k,u]retprobe */
+	PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
+	PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
+};
+
+PMU_FORMAT_ATTR(retprobe, "config:0");
+#endif
+
+#ifdef CONFIG_KPROBE_EVENTS
+static struct attribute *kprobe_attrs[] = {
+	&format_attr_retprobe.attr,
+	NULL,
+};
+
+static struct attribute_group kprobe_format_group = {
+	.name = "format",
+	.attrs = kprobe_attrs,
+};
+
+static const struct attribute_group *kprobe_attr_groups[] = {
+	&kprobe_format_group,
+	NULL,
+};
+
+static int perf_kprobe_event_init(struct perf_event *event);
+static struct pmu perf_kprobe = {
+	.task_ctx_nr	= perf_sw_context,
+	.event_init	= perf_kprobe_event_init,
+	.add		= perf_trace_add,
+	.del		= perf_trace_del,
+	.start		= perf_swevent_start,
+	.stop		= perf_swevent_stop,
+	.read		= perf_swevent_read,
+	.attr_groups	= kprobe_attr_groups,
+};
+
+static int perf_kprobe_event_init(struct perf_event *event)
+{
+	int err;
+	bool is_retprobe;
+
+	if (event->attr.type != perf_kprobe.type)
+		return -ENOENT;
+
+	if (!perfmon_capable())
+		return -EACCES;
+
+	/*
+	 * no branch sampling for probe events
+	 */
+	if (has_branch_stack(event))
+		return -EOPNOTSUPP;
+
+	is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
+	err = perf_kprobe_init(event, is_retprobe);
+	if (err)
+		return err;
+
+	event->destroy = perf_kprobe_destroy;
+
+	return 0;
+}
+#endif /* CONFIG_KPROBE_EVENTS */
+
+#ifdef CONFIG_UPROBE_EVENTS
+PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
+
+static struct attribute *uprobe_attrs[] = {
+	&format_attr_retprobe.attr,
+	&format_attr_ref_ctr_offset.attr,
+	NULL,
+};
+
+static struct attribute_group uprobe_format_group = {
+	.name = "format",
+	.attrs = uprobe_attrs,
+};
+
+static const struct attribute_group *uprobe_attr_groups[] = {
+	&uprobe_format_group,
+	NULL,
+};
+
+static int perf_uprobe_event_init(struct perf_event *event);
+static struct pmu perf_uprobe = {
+	.task_ctx_nr	= perf_sw_context,
+	.event_init	= perf_uprobe_event_init,
+	.add		= perf_trace_add,
+	.del		= perf_trace_del,
+	.start		= perf_swevent_start,
+	.stop		= perf_swevent_stop,
+	.read		= perf_swevent_read,
+	.attr_groups	= uprobe_attr_groups,
+};
+
+static int perf_uprobe_event_init(struct perf_event *event)
+{
+	int err;
+	unsigned long ref_ctr_offset;
+	bool is_retprobe;
+
+	if (event->attr.type != perf_uprobe.type)
+		return -ENOENT;
+
+	if (!perfmon_capable())
+		return -EACCES;
+
+	/*
+	 * no branch sampling for probe events
+	 */
+	if (has_branch_stack(event))
+		return -EOPNOTSUPP;
+
+	is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
+	ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
+	err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
+	if (err)
+		return err;
+
+	event->destroy = perf_uprobe_destroy;
+
+	return 0;
+}
+#endif /* CONFIG_UPROBE_EVENTS */
+
+static inline void perf_tp_register(void)
+{
+	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
+#ifdef CONFIG_KPROBE_EVENTS
+	perf_pmu_register(&perf_kprobe, "kprobe", -1);
+#endif
+#ifdef CONFIG_UPROBE_EVENTS
+	perf_pmu_register(&perf_uprobe, "uprobe", -1);
+#endif
+}
+
+static void perf_event_free_filter(struct perf_event *event)
+{
+	ftrace_profile_free_filter(event);
+}
+
+#ifdef CONFIG_BPF_SYSCALL
+static void bpf_overflow_handler(struct perf_event *event,
+				 struct perf_sample_data *data,
+				 struct pt_regs *regs)
+{
+	struct bpf_perf_event_data_kern ctx = {
+		.data = data,
+		.event = event,
+	};
+	struct bpf_prog *prog;
+	int ret = 0;
+
+	ctx.regs = perf_arch_bpf_user_pt_regs(regs);
+	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
+		goto out;
+	rcu_read_lock();
+	prog = READ_ONCE(event->prog);
+	if (prog) {
+		if (prog->call_get_stack &&
+		    (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) &&
+		    !(data->sample_flags & PERF_SAMPLE_CALLCHAIN)) {
+			data->callchain = perf_callchain(event, regs);
+			data->sample_flags |= PERF_SAMPLE_CALLCHAIN;
+		}
+
+		ret = bpf_prog_run(prog, &ctx);
+	}
+	rcu_read_unlock();
+out:
+	__this_cpu_dec(bpf_prog_active);
+	if (!ret)
+		return;
+
+	event->orig_overflow_handler(event, data, regs);
+}
+
+static int perf_event_set_bpf_handler(struct perf_event *event,
+				      struct bpf_prog *prog,
+				      u64 bpf_cookie)
+{
+	if (event->overflow_handler_context)
+		/* hw breakpoint or kernel counter */
+		return -EINVAL;
+
+	if (event->prog)
+		return -EEXIST;
+
+	if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
+		return -EINVAL;
+
+	if (event->attr.precise_ip &&
+	    prog->call_get_stack &&
+	    (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) ||
+	     event->attr.exclude_callchain_kernel ||
+	     event->attr.exclude_callchain_user)) {
+		/*
+		 * On perf_event with precise_ip, calling bpf_get_stack()
+		 * may trigger unwinder warnings and occasional crashes.
+		 * bpf_get_[stack|stackid] works around this issue by using
+		 * callchain attached to perf_sample_data. If the
+		 * perf_event does not full (kernel and user) callchain
+		 * attached to perf_sample_data, do not allow attaching BPF
+		 * program that calls bpf_get_[stack|stackid].
+		 */
+		return -EPROTO;
+	}
+
+	event->prog = prog;
+	event->bpf_cookie = bpf_cookie;
+	event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
+	WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
+	return 0;
+}
+
+static void perf_event_free_bpf_handler(struct perf_event *event)
+{
+	struct bpf_prog *prog = event->prog;
+
+	if (!prog)
+		return;
+
+	WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
+	event->prog = NULL;
+	bpf_prog_put(prog);
+}
+#else
+static int perf_event_set_bpf_handler(struct perf_event *event,
+				      struct bpf_prog *prog,
+				      u64 bpf_cookie)
+{
+	return -EOPNOTSUPP;
+}
+static void perf_event_free_bpf_handler(struct perf_event *event)
+{
+}
+#endif
+
+/*
+ * returns true if the event is a tracepoint, or a kprobe/upprobe created
+ * with perf_event_open()
+ */
+static inline bool perf_event_is_tracing(struct perf_event *event)
+{
+	if (event->pmu == &perf_tracepoint)
+		return true;
+#ifdef CONFIG_KPROBE_EVENTS
+	if (event->pmu == &perf_kprobe)
+		return true;
+#endif
+#ifdef CONFIG_UPROBE_EVENTS
+	if (event->pmu == &perf_uprobe)
+		return true;
+#endif
+	return false;
+}
+
+int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
+			    u64 bpf_cookie)
+{
+	bool is_kprobe, is_uprobe, is_tracepoint, is_syscall_tp;
+
+	if (!perf_event_is_tracing(event))
+		return perf_event_set_bpf_handler(event, prog, bpf_cookie);
+
+	is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_KPROBE;
+	is_uprobe = event->tp_event->flags & TRACE_EVENT_FL_UPROBE;
+	is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
+	is_syscall_tp = is_syscall_trace_event(event->tp_event);
+	if (!is_kprobe && !is_uprobe && !is_tracepoint && !is_syscall_tp)
+		/* bpf programs can only be attached to u/kprobe or tracepoint */
+		return -EINVAL;
+
+	if (((is_kprobe || is_uprobe) && prog->type != BPF_PROG_TYPE_KPROBE) ||
+	    (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
+	    (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
+		return -EINVAL;
+
+	if (prog->type == BPF_PROG_TYPE_KPROBE && prog->aux->sleepable && !is_uprobe)
+		/* only uprobe programs are allowed to be sleepable */
+		return -EINVAL;
+
+	/* Kprobe override only works for kprobes, not uprobes. */
+	if (prog->kprobe_override && !is_kprobe)
+		return -EINVAL;
+
+	if (is_tracepoint || is_syscall_tp) {
+		int off = trace_event_get_offsets(event->tp_event);
+
+		if (prog->aux->max_ctx_offset > off)
+			return -EACCES;
+	}
+
+	return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
+}
+
+void perf_event_free_bpf_prog(struct perf_event *event)
+{
+	if (!perf_event_is_tracing(event)) {
+		perf_event_free_bpf_handler(event);
+		return;
+	}
+	perf_event_detach_bpf_prog(event);
+}
+
+#else
+
+static inline void perf_tp_register(void)
+{
+}
+
+static void perf_event_free_filter(struct perf_event *event)
+{
+}
+
+int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
+			    u64 bpf_cookie)
+{
+	return -ENOENT;
+}
+
+void perf_event_free_bpf_prog(struct perf_event *event)
+{
+}
+#endif /* CONFIG_EVENT_TRACING */
+
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+void perf_bp_event(struct perf_event *bp, void *data)
+{
+	struct perf_sample_data sample;
+	struct pt_regs *regs = data;
+
+	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
+
+	if (!bp->hw.state && !perf_exclude_event(bp, regs))
+		perf_swevent_event(bp, 1, &sample, regs);
+}
+#endif
+
+/*
+ * Allocate a new address filter
+ */
+static struct perf_addr_filter *
+perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
+{
+	int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
+	struct perf_addr_filter *filter;
+
+	filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
+	if (!filter)
+		return NULL;
+
+	INIT_LIST_HEAD(&filter->entry);
+	list_add_tail(&filter->entry, filters);
+
+	return filter;
+}
+
+static void free_filters_list(struct list_head *filters)
+{
+	struct perf_addr_filter *filter, *iter;
+
+	list_for_each_entry_safe(filter, iter, filters, entry) {
+		path_put(&filter->path);
+		list_del(&filter->entry);
+		kfree(filter);
+	}
+}
+
+/*
+ * Free existing address filters and optionally install new ones
+ */
+static void perf_addr_filters_splice(struct perf_event *event,
+				     struct list_head *head)
+{
+	unsigned long flags;
+	LIST_HEAD(list);
+
+	if (!has_addr_filter(event))
+		return;
+
+	/* don't bother with children, they don't have their own filters */
+	if (event->parent)
+		return;
+
+	raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
+
+	list_splice_init(&event->addr_filters.list, &list);
+	if (head)
+		list_splice(head, &event->addr_filters.list);
+
+	raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
+
+	free_filters_list(&list);
+}
+
+/*
+ * Scan through mm's vmas and see if one of them matches the
+ * @filter; if so, adjust filter's address range.
+ * Called with mm::mmap_lock down for reading.
+ */
+static void perf_addr_filter_apply(struct perf_addr_filter *filter,
+				   struct mm_struct *mm,
+				   struct perf_addr_filter_range *fr)
+{
+	struct vm_area_struct *vma;
+	VMA_ITERATOR(vmi, mm, 0);
+
+	for_each_vma(vmi, vma) {
+		if (!vma->vm_file)
+			continue;
+
+		if (perf_addr_filter_vma_adjust(filter, vma, fr))
+			return;
+	}
+}
+
+/*
+ * Update event's address range filters based on the
+ * task's existing mappings, if any.
+ */
+static void perf_event_addr_filters_apply(struct perf_event *event)
+{
+	struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
+	struct task_struct *task = READ_ONCE(event->ctx->task);
+	struct perf_addr_filter *filter;
+	struct mm_struct *mm = NULL;
+	unsigned int count = 0;
+	unsigned long flags;
+
+	/*
+	 * We may observe TASK_TOMBSTONE, which means that the event tear-down
+	 * will stop on the parent's child_mutex that our caller is also holding
+	 */
+	if (task == TASK_TOMBSTONE)
+		return;
+
+	if (ifh->nr_file_filters) {
+		mm = get_task_mm(task);
+		if (!mm)
+			goto restart;
+
+		mmap_read_lock(mm);
+	}
+
+	raw_spin_lock_irqsave(&ifh->lock, flags);
+	list_for_each_entry(filter, &ifh->list, entry) {
+		if (filter->path.dentry) {
+			/*
+			 * Adjust base offset if the filter is associated to a
+			 * binary that needs to be mapped:
+			 */
+			event->addr_filter_ranges[count].start = 0;
+			event->addr_filter_ranges[count].size = 0;
+
+			perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
+		} else {
+			event->addr_filter_ranges[count].start = filter->offset;
+			event->addr_filter_ranges[count].size  = filter->size;
+		}
+
+		count++;
+	}
+
+	event->addr_filters_gen++;
+	raw_spin_unlock_irqrestore(&ifh->lock, flags);
+
+	if (ifh->nr_file_filters) {
+		mmap_read_unlock(mm);
+
+		mmput(mm);
+	}
+
+restart:
+	perf_event_stop(event, 1);
+}
+
+/*
+ * Address range filtering: limiting the data to certain
+ * instruction address ranges. Filters are ioctl()ed to us from
+ * userspace as ascii strings.
+ *
+ * Filter string format:
+ *
+ * ACTION RANGE_SPEC
+ * where ACTION is one of the
+ *  * "filter": limit the trace to this region
+ *  * "start": start tracing from this address
+ *  * "stop": stop tracing at this address/region;
+ * RANGE_SPEC is
+ *  * for kernel addresses: <start address>[/<size>]
+ *  * for object files:     <start address>[/<size>]@</path/to/object/file>
+ *
+ * if <size> is not specified or is zero, the range is treated as a single
+ * address; not valid for ACTION=="filter".
+ */
+enum {
+	IF_ACT_NONE = -1,
+	IF_ACT_FILTER,
+	IF_ACT_START,
+	IF_ACT_STOP,
+	IF_SRC_FILE,
+	IF_SRC_KERNEL,
+	IF_SRC_FILEADDR,
+	IF_SRC_KERNELADDR,
+};
+
+enum {
+	IF_STATE_ACTION = 0,
+	IF_STATE_SOURCE,
+	IF_STATE_END,
+};
+
+static const match_table_t if_tokens = {
+	{ IF_ACT_FILTER,	"filter" },
+	{ IF_ACT_START,		"start" },
+	{ IF_ACT_STOP,		"stop" },
+	{ IF_SRC_FILE,		"%u/%u@%s" },
+	{ IF_SRC_KERNEL,	"%u/%u" },
+	{ IF_SRC_FILEADDR,	"%u@%s" },
+	{ IF_SRC_KERNELADDR,	"%u" },
+	{ IF_ACT_NONE,		NULL },
+};
+
+/*
+ * Address filter string parser
+ */
+static int
+perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
+			     struct list_head *filters)
+{
+	struct perf_addr_filter *filter = NULL;
+	char *start, *orig, *filename = NULL;
+	substring_t args[MAX_OPT_ARGS];
+	int state = IF_STATE_ACTION, token;
+	unsigned int kernel = 0;
+	int ret = -EINVAL;
+
+	orig = fstr = kstrdup(fstr, GFP_KERNEL);
+	if (!fstr)
+		return -ENOMEM;
+
+	while ((start = strsep(&fstr, " ,\n")) != NULL) {
+		static const enum perf_addr_filter_action_t actions[] = {
+			[IF_ACT_FILTER]	= PERF_ADDR_FILTER_ACTION_FILTER,
+			[IF_ACT_START]	= PERF_ADDR_FILTER_ACTION_START,
+			[IF_ACT_STOP]	= PERF_ADDR_FILTER_ACTION_STOP,
+		};
+		ret = -EINVAL;
+
+		if (!*start)
+			continue;
+
+		/* filter definition begins */
+		if (state == IF_STATE_ACTION) {
+			filter = perf_addr_filter_new(event, filters);
+			if (!filter)
+				goto fail;
+		}
+
+		token = match_token(start, if_tokens, args);
+		switch (token) {
+		case IF_ACT_FILTER:
+		case IF_ACT_START:
+		case IF_ACT_STOP:
+			if (state != IF_STATE_ACTION)
+				goto fail;
+
+			filter->action = actions[token];
+			state = IF_STATE_SOURCE;
+			break;
+
+		case IF_SRC_KERNELADDR:
+		case IF_SRC_KERNEL:
+			kernel = 1;
+			fallthrough;
+
+		case IF_SRC_FILEADDR:
+		case IF_SRC_FILE:
+			if (state != IF_STATE_SOURCE)
+				goto fail;
+
+			*args[0].to = 0;
+			ret = kstrtoul(args[0].from, 0, &filter->offset);
+			if (ret)
+				goto fail;
+
+			if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
+				*args[1].to = 0;
+				ret = kstrtoul(args[1].from, 0, &filter->size);
+				if (ret)
+					goto fail;
+			}
+
+			if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
+				int fpos = token == IF_SRC_FILE ? 2 : 1;
+
+				kfree(filename);
+				filename = match_strdup(&args[fpos]);
+				if (!filename) {
+					ret = -ENOMEM;
+					goto fail;
+				}
+			}
+
+			state = IF_STATE_END;
+			break;
+
+		default:
+			goto fail;
+		}
+
+		/*
+		 * Filter definition is fully parsed, validate and install it.
+		 * Make sure that it doesn't contradict itself or the event's
+		 * attribute.
+		 */
+		if (state == IF_STATE_END) {
+			ret = -EINVAL;
+
+			/*
+			 * ACTION "filter" must have a non-zero length region
+			 * specified.
+			 */
+			if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
+			    !filter->size)
+				goto fail;
+
+			if (!kernel) {
+				if (!filename)
+					goto fail;
+
+				/*
+				 * For now, we only support file-based filters
+				 * in per-task events; doing so for CPU-wide
+				 * events requires additional context switching
+				 * trickery, since same object code will be
+				 * mapped at different virtual addresses in
+				 * different processes.
+				 */
+				ret = -EOPNOTSUPP;
+				if (!event->ctx->task)
+					goto fail;
+
+				/* look up the path and grab its inode */
+				ret = kern_path(filename, LOOKUP_FOLLOW,
+						&filter->path);
+				if (ret)
+					goto fail;
+
+				ret = -EINVAL;
+				if (!filter->path.dentry ||
+				    !S_ISREG(d_inode(filter->path.dentry)
+					     ->i_mode))
+					goto fail;
+
+				event->addr_filters.nr_file_filters++;
+			}
+
+			/* ready to consume more filters */
+			kfree(filename);
+			filename = NULL;
+			state = IF_STATE_ACTION;
+			filter = NULL;
+			kernel = 0;
+		}
+	}
+
+	if (state != IF_STATE_ACTION)
+		goto fail;
+
+	kfree(filename);
+	kfree(orig);
+
+	return 0;
+
+fail:
+	kfree(filename);
+	free_filters_list(filters);
+	kfree(orig);
+
+	return ret;
+}
+
+static int
+perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
+{
+	LIST_HEAD(filters);
+	int ret;
+
+	/*
+	 * Since this is called in perf_ioctl() path, we're already holding
+	 * ctx::mutex.
+	 */
+	lockdep_assert_held(&event->ctx->mutex);
+
+	if (WARN_ON_ONCE(event->parent))
+		return -EINVAL;
+
+	ret = perf_event_parse_addr_filter(event, filter_str, &filters);
+	if (ret)
+		goto fail_clear_files;
+
+	ret = event->pmu->addr_filters_validate(&filters);
+	if (ret)
+		goto fail_free_filters;
+
+	/* remove existing filters, if any */
+	perf_addr_filters_splice(event, &filters);
+
+	/* install new filters */
+	perf_event_for_each_child(event, perf_event_addr_filters_apply);
+
+	return ret;
+
+fail_free_filters:
+	free_filters_list(&filters);
+
+fail_clear_files:
+	event->addr_filters.nr_file_filters = 0;
+
+	return ret;
+}
+
+static int perf_event_set_filter(struct perf_event *event, void __user *arg)
+{
+	int ret = -EINVAL;
+	char *filter_str;
+
+	filter_str = strndup_user(arg, PAGE_SIZE);
+	if (IS_ERR(filter_str))
+		return PTR_ERR(filter_str);
+
+#ifdef CONFIG_EVENT_TRACING
+	if (perf_event_is_tracing(event)) {
+		struct perf_event_context *ctx = event->ctx;
+
+		/*
+		 * Beware, here be dragons!!
+		 *
+		 * the tracepoint muck will deadlock against ctx->mutex, but
+		 * the tracepoint stuff does not actually need it. So
+		 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
+		 * already have a reference on ctx.
+		 *
+		 * This can result in event getting moved to a different ctx,
+		 * but that does not affect the tracepoint state.
+		 */
+		mutex_unlock(&ctx->mutex);
+		ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
+		mutex_lock(&ctx->mutex);
+	} else
+#endif
+	if (has_addr_filter(event))
+		ret = perf_event_set_addr_filter(event, filter_str);
+
+	kfree(filter_str);
+	return ret;
+}
+
+/*
+ * hrtimer based swevent callback
+ */
+
+static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
+{
+	enum hrtimer_restart ret = HRTIMER_RESTART;
+	struct perf_sample_data data;
+	struct pt_regs *regs;
+	struct perf_event *event;
+	u64 period;
+
+	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
+
+	if (event->state != PERF_EVENT_STATE_ACTIVE)
+		return HRTIMER_NORESTART;
+
+	event->pmu->read(event);
+
+	perf_sample_data_init(&data, 0, event->hw.last_period);
+	regs = get_irq_regs();
+
+	if (regs && !perf_exclude_event(event, regs)) {
+		if (!(event->attr.exclude_idle && is_idle_task(current)))
+			if (__perf_event_overflow(event, 1, &data, regs))
+				ret = HRTIMER_NORESTART;
+	}
+
+	period = max_t(u64, 10000, event->hw.sample_period);
+	hrtimer_forward_now(hrtimer, ns_to_ktime(period));
+
+	return ret;
+}
+
+static void perf_swevent_start_hrtimer(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	s64 period;
+
+	if (!is_sampling_event(event))
+		return;
+
+	period = local64_read(&hwc->period_left);
+	if (period) {
+		if (period < 0)
+			period = 10000;
+
+		local64_set(&hwc->period_left, 0);
+	} else {
+		period = max_t(u64, 10000, hwc->sample_period);
+	}
+	hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
+		      HRTIMER_MODE_REL_PINNED_HARD);
+}
+
+static void perf_swevent_cancel_hrtimer(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (is_sampling_event(event)) {
+		ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
+		local64_set(&hwc->period_left, ktime_to_ns(remaining));
+
+		hrtimer_cancel(&hwc->hrtimer);
+	}
+}
+
+static void perf_swevent_init_hrtimer(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (!is_sampling_event(event))
+		return;
+
+	hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	hwc->hrtimer.function = perf_swevent_hrtimer;
+
+	/*
+	 * Since hrtimers have a fixed rate, we can do a static freq->period
+	 * mapping and avoid the whole period adjust feedback stuff.
+	 */
+	if (event->attr.freq) {
+		long freq = event->attr.sample_freq;
+
+		event->attr.sample_period = NSEC_PER_SEC / freq;
+		hwc->sample_period = event->attr.sample_period;
+		local64_set(&hwc->period_left, hwc->sample_period);
+		hwc->last_period = hwc->sample_period;
+		event->attr.freq = 0;
+	}
+}
+
+/*
+ * Software event: cpu wall time clock
+ */
+
+static void cpu_clock_event_update(struct perf_event *event)
+{
+	s64 prev;
+	u64 now;
+
+	now = local_clock();
+	prev = local64_xchg(&event->hw.prev_count, now);
+	local64_add(now - prev, &event->count);
+}
+
+static void cpu_clock_event_start(struct perf_event *event, int flags)
+{
+	local64_set(&event->hw.prev_count, local_clock());
+	perf_swevent_start_hrtimer(event);
+}
+
+static void cpu_clock_event_stop(struct perf_event *event, int flags)
+{
+	perf_swevent_cancel_hrtimer(event);
+	cpu_clock_event_update(event);
+}
+
+static int cpu_clock_event_add(struct perf_event *event, int flags)
+{
+	if (flags & PERF_EF_START)
+		cpu_clock_event_start(event, flags);
+	perf_event_update_userpage(event);
+
+	return 0;
+}
+
+static void cpu_clock_event_del(struct perf_event *event, int flags)
+{
+	cpu_clock_event_stop(event, flags);
+}
+
+static void cpu_clock_event_read(struct perf_event *event)
+{
+	cpu_clock_event_update(event);
+}
+
+static int cpu_clock_event_init(struct perf_event *event)
+{
+	if (event->attr.type != PERF_TYPE_SOFTWARE)
+		return -ENOENT;
+
+	if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
+		return -ENOENT;
+
+	/*
+	 * no branch sampling for software events
+	 */
+	if (has_branch_stack(event))
+		return -EOPNOTSUPP;
+
+	perf_swevent_init_hrtimer(event);
+
+	return 0;
+}
+
+static struct pmu perf_cpu_clock = {
+	.task_ctx_nr	= perf_sw_context,
+
+	.capabilities	= PERF_PMU_CAP_NO_NMI,
+
+	.event_init	= cpu_clock_event_init,
+	.add		= cpu_clock_event_add,
+	.del		= cpu_clock_event_del,
+	.start		= cpu_clock_event_start,
+	.stop		= cpu_clock_event_stop,
+	.read		= cpu_clock_event_read,
+};
+
+/*
+ * Software event: task time clock
+ */
+
+static void task_clock_event_update(struct perf_event *event, u64 now)
+{
+	u64 prev;
+	s64 delta;
+
+	prev = local64_xchg(&event->hw.prev_count, now);
+	delta = now - prev;
+	local64_add(delta, &event->count);
+}
+
+static void task_clock_event_start(struct perf_event *event, int flags)
+{
+	local64_set(&event->hw.prev_count, event->ctx->time);
+	perf_swevent_start_hrtimer(event);
+}
+
+static void task_clock_event_stop(struct perf_event *event, int flags)
+{
+	perf_swevent_cancel_hrtimer(event);
+	task_clock_event_update(event, event->ctx->time);
+}
+
+static int task_clock_event_add(struct perf_event *event, int flags)
+{
+	if (flags & PERF_EF_START)
+		task_clock_event_start(event, flags);
+	perf_event_update_userpage(event);
+
+	return 0;
+}
+
+static void task_clock_event_del(struct perf_event *event, int flags)
+{
+	task_clock_event_stop(event, PERF_EF_UPDATE);
+}
+
+static void task_clock_event_read(struct perf_event *event)
+{
+	u64 now = perf_clock();
+	u64 delta = now - event->ctx->timestamp;
+	u64 time = event->ctx->time + delta;
+
+	task_clock_event_update(event, time);
+}
+
+static int task_clock_event_init(struct perf_event *event)
+{
+	if (event->attr.type != PERF_TYPE_SOFTWARE)
+		return -ENOENT;
+
+	if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
+		return -ENOENT;
+
+	/*
+	 * no branch sampling for software events
+	 */
+	if (has_branch_stack(event))
+		return -EOPNOTSUPP;
+
+	perf_swevent_init_hrtimer(event);
+
+	return 0;
+}
+
+static struct pmu perf_task_clock = {
+	.task_ctx_nr	= perf_sw_context,
+
+	.capabilities	= PERF_PMU_CAP_NO_NMI,
+
+	.event_init	= task_clock_event_init,
+	.add		= task_clock_event_add,
+	.del		= task_clock_event_del,
+	.start		= task_clock_event_start,
+	.stop		= task_clock_event_stop,
+	.read		= task_clock_event_read,
+};
+
+static void perf_pmu_nop_void(struct pmu *pmu)
+{
+}
+
+static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
+{
+}
+
+static int perf_pmu_nop_int(struct pmu *pmu)
+{
+	return 0;
+}
+
+static int perf_event_nop_int(struct perf_event *event, u64 value)
+{
+	return 0;
+}
+
+static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
+
+static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
+{
+	__this_cpu_write(nop_txn_flags, flags);
+
+	if (flags & ~PERF_PMU_TXN_ADD)
+		return;
+
+	perf_pmu_disable(pmu);
+}
+
+static int perf_pmu_commit_txn(struct pmu *pmu)
+{
+	unsigned int flags = __this_cpu_read(nop_txn_flags);
+
+	__this_cpu_write(nop_txn_flags, 0);
+
+	if (flags & ~PERF_PMU_TXN_ADD)
+		return 0;
+
+	perf_pmu_enable(pmu);
+	return 0;
+}
+
+static void perf_pmu_cancel_txn(struct pmu *pmu)
+{
+	unsigned int flags =  __this_cpu_read(nop_txn_flags);
+
+	__this_cpu_write(nop_txn_flags, 0);
+
+	if (flags & ~PERF_PMU_TXN_ADD)
+		return;
+
+	perf_pmu_enable(pmu);
+}
+
+static int perf_event_idx_default(struct perf_event *event)
+{
+	return 0;
+}
+
+/*
+ * Ensures all contexts with the same task_ctx_nr have the same
+ * pmu_cpu_context too.
+ */
+static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
+{
+	struct pmu *pmu;
+
+	if (ctxn < 0)
+		return NULL;
+
+	list_for_each_entry(pmu, &pmus, entry) {
+		if (pmu->task_ctx_nr == ctxn)
+			return pmu->pmu_cpu_context;
+	}
+
+	return NULL;
+}
+
+static void free_pmu_context(struct pmu *pmu)
+{
+	/*
+	 * Static contexts such as perf_sw_context have a global lifetime
+	 * and may be shared between different PMUs. Avoid freeing them
+	 * when a single PMU is going away.
+	 */
+	if (pmu->task_ctx_nr > perf_invalid_context)
+		return;
+
+	free_percpu(pmu->pmu_cpu_context);
+}
+
+/*
+ * Let userspace know that this PMU supports address range filtering:
+ */
+static ssize_t nr_addr_filters_show(struct device *dev,
+				    struct device_attribute *attr,
+				    char *page)
+{
+	struct pmu *pmu = dev_get_drvdata(dev);
+
+	return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
+}
+DEVICE_ATTR_RO(nr_addr_filters);
+
+static struct idr pmu_idr;
+
+static ssize_t
+type_show(struct device *dev, struct device_attribute *attr, char *page)
+{
+	struct pmu *pmu = dev_get_drvdata(dev);
+
+	return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->type);
+}
+static DEVICE_ATTR_RO(type);
+
+static ssize_t
+perf_event_mux_interval_ms_show(struct device *dev,
+				struct device_attribute *attr,
+				char *page)
+{
+	struct pmu *pmu = dev_get_drvdata(dev);
+
+	return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->hrtimer_interval_ms);
+}
+
+static DEFINE_MUTEX(mux_interval_mutex);
+
+static ssize_t
+perf_event_mux_interval_ms_store(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *buf, size_t count)
+{
+	struct pmu *pmu = dev_get_drvdata(dev);
+	int timer, cpu, ret;
+
+	ret = kstrtoint(buf, 0, &timer);
+	if (ret)
+		return ret;
+
+	if (timer < 1)
+		return -EINVAL;
+
+	/* same value, noting to do */
+	if (timer == pmu->hrtimer_interval_ms)
+		return count;
+
+	mutex_lock(&mux_interval_mutex);
+	pmu->hrtimer_interval_ms = timer;
+
+	/* update all cpuctx for this PMU */
+	cpus_read_lock();
+	for_each_online_cpu(cpu) {
+		struct perf_cpu_context *cpuctx;
+		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
+		cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
+
+		cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpuctx);
+	}
+	cpus_read_unlock();
+	mutex_unlock(&mux_interval_mutex);
+
+	return count;
+}
+static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
+
+static struct attribute *pmu_dev_attrs[] = {
+	&dev_attr_type.attr,
+	&dev_attr_perf_event_mux_interval_ms.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(pmu_dev);
+
+static int pmu_bus_running;
+static struct bus_type pmu_bus = {
+	.name		= "event_source",
+	.dev_groups	= pmu_dev_groups,
+};
+
+static void pmu_dev_release(struct device *dev)
+{
+	kfree(dev);
+}
+
+static int pmu_dev_alloc(struct pmu *pmu)
+{
+	int ret = -ENOMEM;
+
+	pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
+	if (!pmu->dev)
+		goto out;
+
+	pmu->dev->groups = pmu->attr_groups;
+	device_initialize(pmu->dev);
+
+	dev_set_drvdata(pmu->dev, pmu);
+	pmu->dev->bus = &pmu_bus;
+	pmu->dev->release = pmu_dev_release;
+
+	ret = dev_set_name(pmu->dev, "%s", pmu->name);
+	if (ret)
+		goto free_dev;
+
+	ret = device_add(pmu->dev);
+	if (ret)
+		goto free_dev;
+
+	/* For PMUs with address filters, throw in an extra attribute: */
+	if (pmu->nr_addr_filters)
+		ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
+
+	if (ret)
+		goto del_dev;
+
+	if (pmu->attr_update)
+		ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
+
+	if (ret)
+		goto del_dev;
+
+out:
+	return ret;
+
+del_dev:
+	device_del(pmu->dev);
+
+free_dev:
+	put_device(pmu->dev);
+	goto out;
+}
+
+static struct lock_class_key cpuctx_mutex;
+static struct lock_class_key cpuctx_lock;
+
+int perf_pmu_register(struct pmu *pmu, const char *name, int type)
+{
+	int cpu, ret, max = PERF_TYPE_MAX;
+
+	mutex_lock(&pmus_lock);
+	ret = -ENOMEM;
+	pmu->pmu_disable_count = alloc_percpu(int);
+	if (!pmu->pmu_disable_count)
+		goto unlock;
+
+	pmu->type = -1;
+	if (!name)
+		goto skip_type;
+	pmu->name = name;
+
+	if (type != PERF_TYPE_SOFTWARE) {
+		if (type >= 0)
+			max = type;
+
+		ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
+		if (ret < 0)
+			goto free_pdc;
+
+		WARN_ON(type >= 0 && ret != type);
+
+		type = ret;
+	}
+	pmu->type = type;
+
+	if (pmu_bus_running) {
+		ret = pmu_dev_alloc(pmu);
+		if (ret)
+			goto free_idr;
+	}
+
+skip_type:
+	if (pmu->task_ctx_nr == perf_hw_context) {
+		static int hw_context_taken = 0;
+
+		/*
+		 * Other than systems with heterogeneous CPUs, it never makes
+		 * sense for two PMUs to share perf_hw_context. PMUs which are
+		 * uncore must use perf_invalid_context.
+		 */
+		if (WARN_ON_ONCE(hw_context_taken &&
+		    !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
+			pmu->task_ctx_nr = perf_invalid_context;
+
+		hw_context_taken = 1;
+	}
+
+	pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
+	if (pmu->pmu_cpu_context)
+		goto got_cpu_context;
+
+	ret = -ENOMEM;
+	pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
+	if (!pmu->pmu_cpu_context)
+		goto free_dev;
+
+	for_each_possible_cpu(cpu) {
+		struct perf_cpu_context *cpuctx;
+
+		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
+		__perf_event_init_context(&cpuctx->ctx);
+		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
+		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
+		cpuctx->ctx.pmu = pmu;
+		cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
+
+		__perf_mux_hrtimer_init(cpuctx, cpu);
+
+		cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
+		cpuctx->heap = cpuctx->heap_default;
+	}
+
+got_cpu_context:
+	if (!pmu->start_txn) {
+		if (pmu->pmu_enable) {
+			/*
+			 * If we have pmu_enable/pmu_disable calls, install
+			 * transaction stubs that use that to try and batch
+			 * hardware accesses.
+			 */
+			pmu->start_txn  = perf_pmu_start_txn;
+			pmu->commit_txn = perf_pmu_commit_txn;
+			pmu->cancel_txn = perf_pmu_cancel_txn;
+		} else {
+			pmu->start_txn  = perf_pmu_nop_txn;
+			pmu->commit_txn = perf_pmu_nop_int;
+			pmu->cancel_txn = perf_pmu_nop_void;
+		}
+	}
+
+	if (!pmu->pmu_enable) {
+		pmu->pmu_enable  = perf_pmu_nop_void;
+		pmu->pmu_disable = perf_pmu_nop_void;
+	}
+
+	if (!pmu->check_period)
+		pmu->check_period = perf_event_nop_int;
+
+	if (!pmu->event_idx)
+		pmu->event_idx = perf_event_idx_default;
+
+	/*
+	 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
+	 * since these cannot be in the IDR. This way the linear search
+	 * is fast, provided a valid software event is provided.
+	 */
+	if (type == PERF_TYPE_SOFTWARE || !name)
+		list_add_rcu(&pmu->entry, &pmus);
+	else
+		list_add_tail_rcu(&pmu->entry, &pmus);
+
+	atomic_set(&pmu->exclusive_cnt, 0);
+	ret = 0;
+unlock:
+	mutex_unlock(&pmus_lock);
+
+	return ret;
+
+free_dev:
+	device_del(pmu->dev);
+	put_device(pmu->dev);
+
+free_idr:
+	if (pmu->type != PERF_TYPE_SOFTWARE)
+		idr_remove(&pmu_idr, pmu->type);
+
+free_pdc:
+	free_percpu(pmu->pmu_disable_count);
+	goto unlock;
+}
+EXPORT_SYMBOL_GPL(perf_pmu_register);
+
+void perf_pmu_unregister(struct pmu *pmu)
+{
+	mutex_lock(&pmus_lock);
+	list_del_rcu(&pmu->entry);
+
+	/*
+	 * We dereference the pmu list under both SRCU and regular RCU, so
+	 * synchronize against both of those.
+	 */
+	synchronize_srcu(&pmus_srcu);
+	synchronize_rcu();
+
+	free_percpu(pmu->pmu_disable_count);
+	if (pmu->type != PERF_TYPE_SOFTWARE)
+		idr_remove(&pmu_idr, pmu->type);
+	if (pmu_bus_running) {
+		if (pmu->nr_addr_filters)
+			device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
+		device_del(pmu->dev);
+		put_device(pmu->dev);
+	}
+	free_pmu_context(pmu);
+	mutex_unlock(&pmus_lock);
+}
+EXPORT_SYMBOL_GPL(perf_pmu_unregister);
+
+static inline bool has_extended_regs(struct perf_event *event)
+{
+	return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
+	       (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
+}
+
+static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
+{
+	struct perf_event_context *ctx = NULL;
+	int ret;
+
+	if (!try_module_get(pmu->module))
+		return -ENODEV;
+
+	/*
+	 * A number of pmu->event_init() methods iterate the sibling_list to,
+	 * for example, validate if the group fits on the PMU. Therefore,
+	 * if this is a sibling event, acquire the ctx->mutex to protect
+	 * the sibling_list.
+	 */
+	if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
+		/*
+		 * This ctx->mutex can nest when we're called through
+		 * inheritance. See the perf_event_ctx_lock_nested() comment.
+		 */
+		ctx = perf_event_ctx_lock_nested(event->group_leader,
+						 SINGLE_DEPTH_NESTING);
+		BUG_ON(!ctx);
+	}
+
+	event->pmu = pmu;
+	ret = pmu->event_init(event);
+
+	if (ctx)
+		perf_event_ctx_unlock(event->group_leader, ctx);
+
+	if (!ret) {
+		if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
+		    has_extended_regs(event))
+			ret = -EOPNOTSUPP;
+
+		if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
+		    event_has_any_exclude_flag(event))
+			ret = -EINVAL;
+
+		if (ret && event->destroy)
+			event->destroy(event);
+	}
+
+	if (ret)
+		module_put(pmu->module);
+
+	return ret;
+}
+
+static struct pmu *perf_init_event(struct perf_event *event)
+{
+	bool extended_type = false;
+	int idx, type, ret;
+	struct pmu *pmu;
+
+	idx = srcu_read_lock(&pmus_srcu);
+
+	/* Try parent's PMU first: */
+	if (event->parent && event->parent->pmu) {
+		pmu = event->parent->pmu;
+		ret = perf_try_init_event(pmu, event);
+		if (!ret)
+			goto unlock;
+	}
+
+	/*
+	 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
+	 * are often aliases for PERF_TYPE_RAW.
+	 */
+	type = event->attr.type;
+	if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
+		type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
+		if (!type) {
+			type = PERF_TYPE_RAW;
+		} else {
+			extended_type = true;
+			event->attr.config &= PERF_HW_EVENT_MASK;
+		}
+	}
+
+again:
+	rcu_read_lock();
+	pmu = idr_find(&pmu_idr, type);
+	rcu_read_unlock();
+	if (pmu) {
+		if (event->attr.type != type && type != PERF_TYPE_RAW &&
+		    !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
+			goto fail;
+
+		ret = perf_try_init_event(pmu, event);
+		if (ret == -ENOENT && event->attr.type != type && !extended_type) {
+			type = event->attr.type;
+			goto again;
+		}
+
+		if (ret)
+			pmu = ERR_PTR(ret);
+
+		goto unlock;
+	}
+
+	list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
+		ret = perf_try_init_event(pmu, event);
+		if (!ret)
+			goto unlock;
+
+		if (ret != -ENOENT) {
+			pmu = ERR_PTR(ret);
+			goto unlock;
+		}
+	}
+fail:
+	pmu = ERR_PTR(-ENOENT);
+unlock:
+	srcu_read_unlock(&pmus_srcu, idx);
+
+	return pmu;
+}
+
+static void attach_sb_event(struct perf_event *event)
+{
+	struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
+
+	raw_spin_lock(&pel->lock);
+	list_add_rcu(&event->sb_list, &pel->list);
+	raw_spin_unlock(&pel->lock);
+}
+
+/*
+ * We keep a list of all !task (and therefore per-cpu) events
+ * that need to receive side-band records.
+ *
+ * This avoids having to scan all the various PMU per-cpu contexts
+ * looking for them.
+ */
+static void account_pmu_sb_event(struct perf_event *event)
+{
+	if (is_sb_event(event))
+		attach_sb_event(event);
+}
+
+static void account_event_cpu(struct perf_event *event, int cpu)
+{
+	if (event->parent)
+		return;
+
+	if (is_cgroup_event(event))
+		atomic_inc(&per_cpu(perf_cgroup_events, cpu));
+}
+
+/* Freq events need the tick to stay alive (see perf_event_task_tick). */
+static void account_freq_event_nohz(void)
+{
+#ifdef CONFIG_NO_HZ_FULL
+	/* Lock so we don't race with concurrent unaccount */
+	spin_lock(&nr_freq_lock);
+	if (atomic_inc_return(&nr_freq_events) == 1)
+		tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
+	spin_unlock(&nr_freq_lock);
+#endif
+}
+
+static void account_freq_event(void)
+{
+	if (tick_nohz_full_enabled())
+		account_freq_event_nohz();
+	else
+		atomic_inc(&nr_freq_events);
+}
+
+
+static void account_event(struct perf_event *event)
+{
+	bool inc = false;
+
+	if (event->parent)
+		return;
+
+	if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
+		inc = true;
+	if (event->attr.mmap || event->attr.mmap_data)
+		atomic_inc(&nr_mmap_events);
+	if (event->attr.build_id)
+		atomic_inc(&nr_build_id_events);
+	if (event->attr.comm)
+		atomic_inc(&nr_comm_events);
+	if (event->attr.namespaces)
+		atomic_inc(&nr_namespaces_events);
+	if (event->attr.cgroup)
+		atomic_inc(&nr_cgroup_events);
+	if (event->attr.task)
+		atomic_inc(&nr_task_events);
+	if (event->attr.freq)
+		account_freq_event();
+	if (event->attr.context_switch) {
+		atomic_inc(&nr_switch_events);
+		inc = true;
+	}
+	if (has_branch_stack(event))
+		inc = true;
+	if (is_cgroup_event(event))
+		inc = true;
+	if (event->attr.ksymbol)
+		atomic_inc(&nr_ksymbol_events);
+	if (event->attr.bpf_event)
+		atomic_inc(&nr_bpf_events);
+	if (event->attr.text_poke)
+		atomic_inc(&nr_text_poke_events);
+
+	if (inc) {
+		/*
+		 * We need the mutex here because static_branch_enable()
+		 * must complete *before* the perf_sched_count increment
+		 * becomes visible.
+		 */
+		if (atomic_inc_not_zero(&perf_sched_count))
+			goto enabled;
+
+		mutex_lock(&perf_sched_mutex);
+		if (!atomic_read(&perf_sched_count)) {
+			static_branch_enable(&perf_sched_events);
+			/*
+			 * Guarantee that all CPUs observe they key change and
+			 * call the perf scheduling hooks before proceeding to
+			 * install events that need them.
+			 */
+			synchronize_rcu();
+		}
+		/*
+		 * Now that we have waited for the sync_sched(), allow further
+		 * increments to by-pass the mutex.
+		 */
+		atomic_inc(&perf_sched_count);
+		mutex_unlock(&perf_sched_mutex);
+	}
+enabled:
+
+	account_event_cpu(event, event->cpu);
+
+	account_pmu_sb_event(event);
+}
+
+/*
+ * Allocate and initialize an event structure
+ */
+static struct perf_event *
+perf_event_alloc(struct perf_event_attr *attr, int cpu,
+		 struct task_struct *task,
+		 struct perf_event *group_leader,
+		 struct perf_event *parent_event,
+		 perf_overflow_handler_t overflow_handler,
+		 void *context, int cgroup_fd)
+{
+	struct pmu *pmu;
+	struct perf_event *event;
+	struct hw_perf_event *hwc;
+	long err = -EINVAL;
+	int node;
+
+	if ((unsigned)cpu >= nr_cpu_ids) {
+		if (!task || cpu != -1)
+			return ERR_PTR(-EINVAL);
+	}
+	if (attr->sigtrap && !task) {
+		/* Requires a task: avoid signalling random tasks. */
+		return ERR_PTR(-EINVAL);
+	}
+
+	node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
+	event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
+				      node);
+	if (!event)
+		return ERR_PTR(-ENOMEM);
+
+	/*
+	 * Single events are their own group leaders, with an
+	 * empty sibling list:
+	 */
+	if (!group_leader)
+		group_leader = event;
+
+	mutex_init(&event->child_mutex);
+	INIT_LIST_HEAD(&event->child_list);
+
+	INIT_LIST_HEAD(&event->event_entry);
+	INIT_LIST_HEAD(&event->sibling_list);
+	INIT_LIST_HEAD(&event->active_list);
+	init_event_group(event);
+	INIT_LIST_HEAD(&event->rb_entry);
+	INIT_LIST_HEAD(&event->active_entry);
+	INIT_LIST_HEAD(&event->addr_filters.list);
+	INIT_HLIST_NODE(&event->hlist_entry);
+
+
+	init_waitqueue_head(&event->waitq);
+	init_irq_work(&event->pending_irq, perf_pending_irq);
+	init_task_work(&event->pending_task, perf_pending_task);
+
+	mutex_init(&event->mmap_mutex);
+	raw_spin_lock_init(&event->addr_filters.lock);
+
+	atomic_long_set(&event->refcount, 1);
+	event->cpu		= cpu;
+	event->attr		= *attr;
+	event->group_leader	= group_leader;
+	event->pmu		= NULL;
+	event->oncpu		= -1;
+
+	event->parent		= parent_event;
+
+	event->ns		= get_pid_ns(task_active_pid_ns(current));
+	event->id		= atomic64_inc_return(&perf_event_id);
+
+	event->state		= PERF_EVENT_STATE_INACTIVE;
+
+	if (parent_event)
+		event->event_caps = parent_event->event_caps;
+
+	if (task) {
+		event->attach_state = PERF_ATTACH_TASK;
+		/*
+		 * XXX pmu::event_init needs to know what task to account to
+		 * and we cannot use the ctx information because we need the
+		 * pmu before we get a ctx.
+		 */
+		event->hw.target = get_task_struct(task);
+	}
+
+	event->clock = &local_clock;
+	if (parent_event)
+		event->clock = parent_event->clock;
+
+	if (!overflow_handler && parent_event) {
+		overflow_handler = parent_event->overflow_handler;
+		context = parent_event->overflow_handler_context;
+#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
+		if (overflow_handler == bpf_overflow_handler) {
+			struct bpf_prog *prog = parent_event->prog;
+
+			bpf_prog_inc(prog);
+			event->prog = prog;
+			event->orig_overflow_handler =
+				parent_event->orig_overflow_handler;
+		}
+#endif
+	}
+
+	if (overflow_handler) {
+		event->overflow_handler	= overflow_handler;
+		event->overflow_handler_context = context;
+	} else if (is_write_backward(event)){
+		event->overflow_handler = perf_event_output_backward;
+		event->overflow_handler_context = NULL;
+	} else {
+		event->overflow_handler = perf_event_output_forward;
+		event->overflow_handler_context = NULL;
+	}
+
+	perf_event__state_init(event);
+
+	pmu = NULL;
+
+	hwc = &event->hw;
+	hwc->sample_period = attr->sample_period;
+	if (attr->freq && attr->sample_freq)
+		hwc->sample_period = 1;
+	hwc->last_period = hwc->sample_period;
+
+	local64_set(&hwc->period_left, hwc->sample_period);
+
+	/*
+	 * We currently do not support PERF_SAMPLE_READ on inherited events.
+	 * See perf_output_read().
+	 */
+	if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
+		goto err_ns;
+
+	if (!has_branch_stack(event))
+		event->attr.branch_sample_type = 0;
+
+	pmu = perf_init_event(event);
+	if (IS_ERR(pmu)) {
+		err = PTR_ERR(pmu);
+		goto err_ns;
+	}
+
+	/*
+	 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
+	 * be different on other CPUs in the uncore mask.
+	 */
+	if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
+		err = -EINVAL;
+		goto err_pmu;
+	}
+
+	if (event->attr.aux_output &&
+	    !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
+		err = -EOPNOTSUPP;
+		goto err_pmu;
+	}
+
+	if (cgroup_fd != -1) {
+		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
+		if (err)
+			goto err_pmu;
+	}
+
+	err = exclusive_event_init(event);
+	if (err)
+		goto err_pmu;
+
+	if (has_addr_filter(event)) {
+		event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
+						    sizeof(struct perf_addr_filter_range),
+						    GFP_KERNEL);
+		if (!event->addr_filter_ranges) {
+			err = -ENOMEM;
+			goto err_per_task;
+		}
+
+		/*
+		 * Clone the parent's vma offsets: they are valid until exec()
+		 * even if the mm is not shared with the parent.
+		 */
+		if (event->parent) {
+			struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
+
+			raw_spin_lock_irq(&ifh->lock);
+			memcpy(event->addr_filter_ranges,
+			       event->parent->addr_filter_ranges,
+			       pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
+			raw_spin_unlock_irq(&ifh->lock);
+		}
+
+		/* force hw sync on the address filters */
+		event->addr_filters_gen = 1;
+	}
+
+	if (!event->parent) {
+		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
+			err = get_callchain_buffers(attr->sample_max_stack);
+			if (err)
+				goto err_addr_filters;
+		}
+	}
+
+	err = security_perf_event_alloc(event);
+	if (err)
+		goto err_callchain_buffer;
+
+	/* symmetric to unaccount_event() in _free_event() */
+	account_event(event);
+
+	return event;
+
+err_callchain_buffer:
+	if (!event->parent) {
+		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
+			put_callchain_buffers();
+	}
+err_addr_filters:
+	kfree(event->addr_filter_ranges);
+
+err_per_task:
+	exclusive_event_destroy(event);
+
+err_pmu:
+	if (is_cgroup_event(event))
+		perf_detach_cgroup(event);
+	if (event->destroy)
+		event->destroy(event);
+	module_put(pmu->module);
+err_ns:
+	if (event->hw.target)
+		put_task_struct(event->hw.target);
+	call_rcu(&event->rcu_head, free_event_rcu);
+
+	return ERR_PTR(err);
+}
+
+static int perf_copy_attr(struct perf_event_attr __user *uattr,
+			  struct perf_event_attr *attr)
+{
+	u32 size;
+	int ret;
+
+	/* Zero the full structure, so that a short copy will be nice. */
+	memset(attr, 0, sizeof(*attr));
+
+	ret = get_user(size, &uattr->size);
+	if (ret)
+		return ret;
+
+	/* ABI compatibility quirk: */
+	if (!size)
+		size = PERF_ATTR_SIZE_VER0;
+	if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
+		goto err_size;
+
+	ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
+	if (ret) {
+		if (ret == -E2BIG)
+			goto err_size;
+		return ret;
+	}
+
+	attr->size = size;
+
+	if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
+		return -EINVAL;
+
+	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
+		return -EINVAL;
+
+	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
+		return -EINVAL;
+
+	if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
+		u64 mask = attr->branch_sample_type;
+
+		/* only using defined bits */
+		if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
+			return -EINVAL;
+
+		/* at least one branch bit must be set */
+		if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
+			return -EINVAL;
+
+		/* propagate priv level, when not set for branch */
+		if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
+
+			/* exclude_kernel checked on syscall entry */
+			if (!attr->exclude_kernel)
+				mask |= PERF_SAMPLE_BRANCH_KERNEL;
+
+			if (!attr->exclude_user)
+				mask |= PERF_SAMPLE_BRANCH_USER;
+
+			if (!attr->exclude_hv)
+				mask |= PERF_SAMPLE_BRANCH_HV;
+			/*
+			 * adjust user setting (for HW filter setup)
+			 */
+			attr->branch_sample_type = mask;
+		}
+		/* privileged levels capture (kernel, hv): check permissions */
+		if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
+			ret = perf_allow_kernel(attr);
+			if (ret)
+				return ret;
+		}
+	}
+
+	if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
+		ret = perf_reg_validate(attr->sample_regs_user);
+		if (ret)
+			return ret;
+	}
+
+	if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
+		if (!arch_perf_have_user_stack_dump())
+			return -ENOSYS;
+
+		/*
+		 * We have __u32 type for the size, but so far
+		 * we can only use __u16 as maximum due to the
+		 * __u16 sample size limit.
+		 */
+		if (attr->sample_stack_user >= USHRT_MAX)
+			return -EINVAL;
+		else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
+			return -EINVAL;
+	}
+
+	if (!attr->sample_max_stack)
+		attr->sample_max_stack = sysctl_perf_event_max_stack;
+
+	if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
+		ret = perf_reg_validate(attr->sample_regs_intr);
+
+#ifndef CONFIG_CGROUP_PERF
+	if (attr->sample_type & PERF_SAMPLE_CGROUP)
+		return -EINVAL;
+#endif
+	if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
+	    (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
+		return -EINVAL;
+
+	if (!attr->inherit && attr->inherit_thread)
+		return -EINVAL;
+
+	if (attr->remove_on_exec && attr->enable_on_exec)
+		return -EINVAL;
+
+	if (attr->sigtrap && !attr->remove_on_exec)
+		return -EINVAL;
+
+out:
+	return ret;
+
+err_size:
+	put_user(sizeof(*attr), &uattr->size);
+	ret = -E2BIG;
+	goto out;
+}
+
+static void mutex_lock_double(struct mutex *a, struct mutex *b)
+{
+	if (b < a)
+		swap(a, b);
+
+	mutex_lock(a);
+	mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
+}
+
+static int
+perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
+{
+	struct perf_buffer *rb = NULL;
+	int ret = -EINVAL;
+
+	if (!output_event) {
+		mutex_lock(&event->mmap_mutex);
+		goto set;
+	}
+
+	/* don't allow circular references */
+	if (event == output_event)
+		goto out;
+
+	/*
+	 * Don't allow cross-cpu buffers
+	 */
+	if (output_event->cpu != event->cpu)
+		goto out;
+
+	/*
+	 * If its not a per-cpu rb, it must be the same task.
+	 */
+	if (output_event->cpu == -1 && output_event->hw.target != event->hw.target)
+		goto out;
+
+	/*
+	 * Mixing clocks in the same buffer is trouble you don't need.
+	 */
+	if (output_event->clock != event->clock)
+		goto out;
+
+	/*
+	 * Either writing ring buffer from beginning or from end.
+	 * Mixing is not allowed.
+	 */
+	if (is_write_backward(output_event) != is_write_backward(event))
+		goto out;
+
+	/*
+	 * If both events generate aux data, they must be on the same PMU
+	 */
+	if (has_aux(event) && has_aux(output_event) &&
+	    event->pmu != output_event->pmu)
+		goto out;
+
+	/*
+	 * Hold both mmap_mutex to serialize against perf_mmap_close().  Since
+	 * output_event is already on rb->event_list, and the list iteration
+	 * restarts after every removal, it is guaranteed this new event is
+	 * observed *OR* if output_event is already removed, it's guaranteed we
+	 * observe !rb->mmap_count.
+	 */
+	mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex);
+set:
+	/* Can't redirect output if we've got an active mmap() */
+	if (atomic_read(&event->mmap_count))
+		goto unlock;
+
+	if (output_event) {
+		/* get the rb we want to redirect to */
+		rb = ring_buffer_get(output_event);
+		if (!rb)
+			goto unlock;
+
+		/* did we race against perf_mmap_close() */
+		if (!atomic_read(&rb->mmap_count)) {
+			ring_buffer_put(rb);
+			goto unlock;
+		}
+	}
+
+	ring_buffer_attach(event, rb);
+
+	ret = 0;
+unlock:
+	mutex_unlock(&event->mmap_mutex);
+	if (output_event)
+		mutex_unlock(&output_event->mmap_mutex);
+
+out:
+	return ret;
+}
+
+static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
+{
+	bool nmi_safe = false;
+
+	switch (clk_id) {
+	case CLOCK_MONOTONIC:
+		event->clock = &ktime_get_mono_fast_ns;
+		nmi_safe = true;
+		break;
+
+	case CLOCK_MONOTONIC_RAW:
+		event->clock = &ktime_get_raw_fast_ns;
+		nmi_safe = true;
+		break;
+
+	case CLOCK_REALTIME:
+		event->clock = &ktime_get_real_ns;
+		break;
+
+	case CLOCK_BOOTTIME:
+		event->clock = &ktime_get_boottime_ns;
+		break;
+
+	case CLOCK_TAI:
+		event->clock = &ktime_get_clocktai_ns;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
+		return -EINVAL;
+
+	return 0;
+}
+
+/*
+ * Variation on perf_event_ctx_lock_nested(), except we take two context
+ * mutexes.
+ */
+static struct perf_event_context *
+__perf_event_ctx_lock_double(struct perf_event *group_leader,
+			     struct perf_event_context *ctx)
+{
+	struct perf_event_context *gctx;
+
+again:
+	rcu_read_lock();
+	gctx = READ_ONCE(group_leader->ctx);
+	if (!refcount_inc_not_zero(&gctx->refcount)) {
+		rcu_read_unlock();
+		goto again;
+	}
+	rcu_read_unlock();
+
+	mutex_lock_double(&gctx->mutex, &ctx->mutex);
+
+	if (group_leader->ctx != gctx) {
+		mutex_unlock(&ctx->mutex);
+		mutex_unlock(&gctx->mutex);
+		put_ctx(gctx);
+		goto again;
+	}
+
+	return gctx;
+}
+
+static bool
+perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
+{
+	unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
+	bool is_capable = perfmon_capable();
+
+	if (attr->sigtrap) {
+		/*
+		 * perf_event_attr::sigtrap sends signals to the other task.
+		 * Require the current task to also have CAP_KILL.
+		 */
+		rcu_read_lock();
+		is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
+		rcu_read_unlock();
+
+		/*
+		 * If the required capabilities aren't available, checks for
+		 * ptrace permissions: upgrade to ATTACH, since sending signals
+		 * can effectively change the target task.
+		 */
+		ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
+	}
+
+	/*
+	 * Preserve ptrace permission check for backwards compatibility. The
+	 * ptrace check also includes checks that the current task and other
+	 * task have matching uids, and is therefore not done here explicitly.
+	 */
+	return is_capable || ptrace_may_access(task, ptrace_mode);
+}
+
+/**
+ * sys_perf_event_open - open a performance event, associate it to a task/cpu
+ *
+ * @attr_uptr:	event_id type attributes for monitoring/sampling
+ * @pid:		target pid
+ * @cpu:		target cpu
+ * @group_fd:		group leader event fd
+ * @flags:		perf event open flags
+ */
+SYSCALL_DEFINE5(perf_event_open,
+		struct perf_event_attr __user *, attr_uptr,
+		pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
+{
+	struct perf_event *group_leader = NULL, *output_event = NULL;
+	struct perf_event *event, *sibling;
+	struct perf_event_attr attr;
+	struct perf_event_context *ctx, *gctx;
+	struct file *event_file = NULL;
+	struct fd group = {NULL, 0};
+	struct task_struct *task = NULL;
+	struct pmu *pmu;
+	int event_fd;
+	int move_group = 0;
+	int err;
+	int f_flags = O_RDWR;
+	int cgroup_fd = -1;
+
+	/* for future expandability... */
+	if (flags & ~PERF_FLAG_ALL)
+		return -EINVAL;
+
+	err = perf_copy_attr(attr_uptr, &attr);
+	if (err)
+		return err;
+
+	/* Do we allow access to perf_event_open(2) ? */
+	err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
+	if (err)
+		return err;
+
+	if (!attr.exclude_kernel) {
+		err = perf_allow_kernel(&attr);
+		if (err)
+			return err;
+	}
+
+	if (attr.namespaces) {
+		if (!perfmon_capable())
+			return -EACCES;
+	}
+
+	if (attr.freq) {
+		if (attr.sample_freq > sysctl_perf_event_sample_rate)
+			return -EINVAL;
+	} else {
+		if (attr.sample_period & (1ULL << 63))
+			return -EINVAL;
+	}
+
+	/* Only privileged users can get physical addresses */
+	if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
+		err = perf_allow_kernel(&attr);
+		if (err)
+			return err;
+	}
+
+	/* REGS_INTR can leak data, lockdown must prevent this */
+	if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
+		err = security_locked_down(LOCKDOWN_PERF);
+		if (err)
+			return err;
+	}
+
+	/*
+	 * In cgroup mode, the pid argument is used to pass the fd
+	 * opened to the cgroup directory in cgroupfs. The cpu argument
+	 * designates the cpu on which to monitor threads from that
+	 * cgroup.
+	 */
+	if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
+		return -EINVAL;
+
+	if (flags & PERF_FLAG_FD_CLOEXEC)
+		f_flags |= O_CLOEXEC;
+
+	event_fd = get_unused_fd_flags(f_flags);
+	if (event_fd < 0)
+		return event_fd;
+
+	if (group_fd != -1) {
+		err = perf_fget_light(group_fd, &group);
+		if (err)
+			goto err_fd;
+		group_leader = group.file->private_data;
+		if (flags & PERF_FLAG_FD_OUTPUT)
+			output_event = group_leader;
+		if (flags & PERF_FLAG_FD_NO_GROUP)
+			group_leader = NULL;
+	}
+
+	if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
+		task = find_lively_task_by_vpid(pid);
+		if (IS_ERR(task)) {
+			err = PTR_ERR(task);
+			goto err_group_fd;
+		}
+	}
+
+	if (task && group_leader &&
+	    group_leader->attr.inherit != attr.inherit) {
+		err = -EINVAL;
+		goto err_task;
+	}
+
+	if (flags & PERF_FLAG_PID_CGROUP)
+		cgroup_fd = pid;
+
+	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
+				 NULL, NULL, cgroup_fd);
+	if (IS_ERR(event)) {
+		err = PTR_ERR(event);
+		goto err_task;
+	}
+
+	if (is_sampling_event(event)) {
+		if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
+			err = -EOPNOTSUPP;
+			goto err_alloc;
+		}
+	}
+
+	/*
+	 * Special case software events and allow them to be part of
+	 * any hardware group.
+	 */
+	pmu = event->pmu;
+
+	if (attr.use_clockid) {
+		err = perf_event_set_clock(event, attr.clockid);
+		if (err)
+			goto err_alloc;
+	}
+
+	if (pmu->task_ctx_nr == perf_sw_context)
+		event->event_caps |= PERF_EV_CAP_SOFTWARE;
+
+	if (group_leader) {
+		if (is_software_event(event) &&
+		    !in_software_context(group_leader)) {
+			/*
+			 * If the event is a sw event, but the group_leader
+			 * is on hw context.
+			 *
+			 * Allow the addition of software events to hw
+			 * groups, this is safe because software events
+			 * never fail to schedule.
+			 */
+			pmu = group_leader->ctx->pmu;
+		} else if (!is_software_event(event) &&
+			   is_software_event(group_leader) &&
+			   (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
+			/*
+			 * In case the group is a pure software group, and we
+			 * try to add a hardware event, move the whole group to
+			 * the hardware context.
+			 */
+			move_group = 1;
+		}
+	}
+
+	/*
+	 * Get the target context (task or percpu):
+	 */
+	ctx = find_get_context(pmu, task, event);
+	if (IS_ERR(ctx)) {
+		err = PTR_ERR(ctx);
+		goto err_alloc;
+	}
+
+	/*
+	 * Look up the group leader (we will attach this event to it):
+	 */
+	if (group_leader) {
+		err = -EINVAL;
+
+		/*
+		 * Do not allow a recursive hierarchy (this new sibling
+		 * becoming part of another group-sibling):
+		 */
+		if (group_leader->group_leader != group_leader)
+			goto err_context;
+
+		/* All events in a group should have the same clock */
+		if (group_leader->clock != event->clock)
+			goto err_context;
+
+		/*
+		 * Make sure we're both events for the same CPU;
+		 * grouping events for different CPUs is broken; since
+		 * you can never concurrently schedule them anyhow.
+		 */
+		if (group_leader->cpu != event->cpu)
+			goto err_context;
+
+		/*
+		 * Make sure we're both on the same task, or both
+		 * per-CPU events.
+		 */
+		if (group_leader->ctx->task != ctx->task)
+			goto err_context;
+
+		/*
+		 * Do not allow to attach to a group in a different task
+		 * or CPU context. If we're moving SW events, we'll fix
+		 * this up later, so allow that.
+		 *
+		 * Racy, not holding group_leader->ctx->mutex, see comment with
+		 * perf_event_ctx_lock().
+		 */
+		if (!move_group && group_leader->ctx != ctx)
+			goto err_context;
+
+		/*
+		 * Only a group leader can be exclusive or pinned
+		 */
+		if (attr.exclusive || attr.pinned)
+			goto err_context;
+	}
+
+	if (output_event) {
+		err = perf_event_set_output(event, output_event);
+		if (err)
+			goto err_context;
+	}
+
+	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
+					f_flags);
+	if (IS_ERR(event_file)) {
+		err = PTR_ERR(event_file);
+		event_file = NULL;
+		goto err_context;
+	}
+
+	if (task) {
+		err = down_read_interruptible(&task->signal->exec_update_lock);
+		if (err)
+			goto err_file;
+
+		/*
+		 * We must hold exec_update_lock across this and any potential
+		 * perf_install_in_context() call for this new event to
+		 * serialize against exec() altering our credentials (and the
+		 * perf_event_exit_task() that could imply).
+		 */
+		err = -EACCES;
+		if (!perf_check_permission(&attr, task))
+			goto err_cred;
+	}
+
+	if (move_group) {
+		gctx = __perf_event_ctx_lock_double(group_leader, ctx);
+
+		if (gctx->task == TASK_TOMBSTONE) {
+			err = -ESRCH;
+			goto err_locked;
+		}
+
+		/*
+		 * Check if we raced against another sys_perf_event_open() call
+		 * moving the software group underneath us.
+		 */
+		if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
+			/*
+			 * If someone moved the group out from under us, check
+			 * if this new event wound up on the same ctx, if so
+			 * its the regular !move_group case, otherwise fail.
+			 */
+			if (gctx != ctx) {
+				err = -EINVAL;
+				goto err_locked;
+			} else {
+				perf_event_ctx_unlock(group_leader, gctx);
+				move_group = 0;
+				goto not_move_group;
+			}
+		}
+
+		/*
+		 * Failure to create exclusive events returns -EBUSY.
+		 */
+		err = -EBUSY;
+		if (!exclusive_event_installable(group_leader, ctx))
+			goto err_locked;
+
+		for_each_sibling_event(sibling, group_leader) {
+			if (!exclusive_event_installable(sibling, ctx))
+				goto err_locked;
+		}
+	} else {
+		mutex_lock(&ctx->mutex);
+
+		/*
+		 * Now that we hold ctx->lock, (re)validate group_leader->ctx == ctx,
+		 * see the group_leader && !move_group test earlier.
+		 */
+		if (group_leader && group_leader->ctx != ctx) {
+			err = -EINVAL;
+			goto err_locked;
+		}
+	}
+not_move_group:
+
+	if (ctx->task == TASK_TOMBSTONE) {
+		err = -ESRCH;
+		goto err_locked;
+	}
+
+	if (!perf_event_validate_size(event)) {
+		err = -E2BIG;
+		goto err_locked;
+	}
+
+	if (!task) {
+		/*
+		 * Check if the @cpu we're creating an event for is online.
+		 *
+		 * We use the perf_cpu_context::ctx::mutex to serialize against
+		 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
+		 */
+		struct perf_cpu_context *cpuctx =
+			container_of(ctx, struct perf_cpu_context, ctx);
+
+		if (!cpuctx->online) {
+			err = -ENODEV;
+			goto err_locked;
+		}
+	}
+
+	if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
+		err = -EINVAL;
+		goto err_locked;
+	}
+
+	/*
+	 * Must be under the same ctx::mutex as perf_install_in_context(),
+	 * because we need to serialize with concurrent event creation.
+	 */
+	if (!exclusive_event_installable(event, ctx)) {
+		err = -EBUSY;
+		goto err_locked;
+	}
+
+	WARN_ON_ONCE(ctx->parent_ctx);
+
+	/*
+	 * This is the point on no return; we cannot fail hereafter. This is
+	 * where we start modifying current state.
+	 */
+
+	if (move_group) {
+		/*
+		 * See perf_event_ctx_lock() for comments on the details
+		 * of swizzling perf_event::ctx.
+		 */
+		perf_remove_from_context(group_leader, 0);
+		put_ctx(gctx);
+
+		for_each_sibling_event(sibling, group_leader) {
+			perf_remove_from_context(sibling, 0);
+			put_ctx(gctx);
+		}
+
+		/*
+		 * Wait for everybody to stop referencing the events through
+		 * the old lists, before installing it on new lists.
+		 */
+		synchronize_rcu();
+
+		/*
+		 * Install the group siblings before the group leader.
+		 *
+		 * Because a group leader will try and install the entire group
+		 * (through the sibling list, which is still in-tact), we can
+		 * end up with siblings installed in the wrong context.
+		 *
+		 * By installing siblings first we NO-OP because they're not
+		 * reachable through the group lists.
+		 */
+		for_each_sibling_event(sibling, group_leader) {
+			perf_event__state_init(sibling);
+			perf_install_in_context(ctx, sibling, sibling->cpu);
+			get_ctx(ctx);
+		}
+
+		/*
+		 * Removing from the context ends up with disabled
+		 * event. What we want here is event in the initial
+		 * startup state, ready to be add into new context.
+		 */
+		perf_event__state_init(group_leader);
+		perf_install_in_context(ctx, group_leader, group_leader->cpu);
+		get_ctx(ctx);
+	}
+
+	/*
+	 * Precalculate sample_data sizes; do while holding ctx::mutex such
+	 * that we're serialized against further additions and before
+	 * perf_install_in_context() which is the point the event is active and
+	 * can use these values.
+	 */
+	perf_event__header_size(event);
+	perf_event__id_header_size(event);
+
+	event->owner = current;
+
+	perf_install_in_context(ctx, event, event->cpu);
+	perf_unpin_context(ctx);
+
+	if (move_group)
+		perf_event_ctx_unlock(group_leader, gctx);
+	mutex_unlock(&ctx->mutex);
+
+	if (task) {
+		up_read(&task->signal->exec_update_lock);
+		put_task_struct(task);
+	}
+
+	mutex_lock(&current->perf_event_mutex);
+	list_add_tail(&event->owner_entry, &current->perf_event_list);
+	mutex_unlock(&current->perf_event_mutex);
+
+	/*
+	 * Drop the reference on the group_event after placing the
+	 * new event on the sibling_list. This ensures destruction
+	 * of the group leader will find the pointer to itself in
+	 * perf_group_detach().
+	 */
+	fdput(group);
+	fd_install(event_fd, event_file);
+	return event_fd;
+
+err_locked:
+	if (move_group)
+		perf_event_ctx_unlock(group_leader, gctx);
+	mutex_unlock(&ctx->mutex);
+err_cred:
+	if (task)
+		up_read(&task->signal->exec_update_lock);
+err_file:
+	fput(event_file);
+err_context:
+	perf_unpin_context(ctx);
+	put_ctx(ctx);
+err_alloc:
+	/*
+	 * If event_file is set, the fput() above will have called ->release()
+	 * and that will take care of freeing the event.
+	 */
+	if (!event_file)
+		free_event(event);
+err_task:
+	if (task)
+		put_task_struct(task);
+err_group_fd:
+	fdput(group);
+err_fd:
+	put_unused_fd(event_fd);
+	return err;
+}
+
+/**
+ * perf_event_create_kernel_counter
+ *
+ * @attr: attributes of the counter to create
+ * @cpu: cpu in which the counter is bound
+ * @task: task to profile (NULL for percpu)
+ * @overflow_handler: callback to trigger when we hit the event
+ * @context: context data could be used in overflow_handler callback
+ */
+struct perf_event *
+perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
+				 struct task_struct *task,
+				 perf_overflow_handler_t overflow_handler,
+				 void *context)
+{
+	struct perf_event_context *ctx;
+	struct perf_event *event;
+	int err;
+
+	/*
+	 * Grouping is not supported for kernel events, neither is 'AUX',
+	 * make sure the caller's intentions are adjusted.
+	 */
+	if (attr->aux_output)
+		return ERR_PTR(-EINVAL);
+
+	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
+				 overflow_handler, context, -1);
+	if (IS_ERR(event)) {
+		err = PTR_ERR(event);
+		goto err;
+	}
+
+	/* Mark owner so we could distinguish it from user events. */
+	event->owner = TASK_TOMBSTONE;
+
+	/*
+	 * Get the target context (task or percpu):
+	 */
+	ctx = find_get_context(event->pmu, task, event);
+	if (IS_ERR(ctx)) {
+		err = PTR_ERR(ctx);
+		goto err_free;
+	}
+
+	WARN_ON_ONCE(ctx->parent_ctx);
+	mutex_lock(&ctx->mutex);
+	if (ctx->task == TASK_TOMBSTONE) {
+		err = -ESRCH;
+		goto err_unlock;
+	}
+
+	if (!task) {
+		/*
+		 * Check if the @cpu we're creating an event for is online.
+		 *
+		 * We use the perf_cpu_context::ctx::mutex to serialize against
+		 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
+		 */
+		struct perf_cpu_context *cpuctx =
+			container_of(ctx, struct perf_cpu_context, ctx);
+		if (!cpuctx->online) {
+			err = -ENODEV;
+			goto err_unlock;
+		}
+	}
+
+	if (!exclusive_event_installable(event, ctx)) {
+		err = -EBUSY;
+		goto err_unlock;
+	}
+
+	perf_install_in_context(ctx, event, event->cpu);
+	perf_unpin_context(ctx);
+	mutex_unlock(&ctx->mutex);
+
+	return event;
+
+err_unlock:
+	mutex_unlock(&ctx->mutex);
+	perf_unpin_context(ctx);
+	put_ctx(ctx);
+err_free:
+	free_event(event);
+err:
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
+
+void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
+{
+	struct perf_event_context *src_ctx;
+	struct perf_event_context *dst_ctx;
+	struct perf_event *event, *tmp;
+	LIST_HEAD(events);
+
+	src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
+	dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
+
+	/*
+	 * See perf_event_ctx_lock() for comments on the details
+	 * of swizzling perf_event::ctx.
+	 */
+	mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
+	list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
+				 event_entry) {
+		perf_remove_from_context(event, 0);
+		unaccount_event_cpu(event, src_cpu);
+		put_ctx(src_ctx);
+		list_add(&event->migrate_entry, &events);
+	}
+
+	/*
+	 * Wait for the events to quiesce before re-instating them.
+	 */
+	synchronize_rcu();
+
+	/*
+	 * Re-instate events in 2 passes.
+	 *
+	 * Skip over group leaders and only install siblings on this first
+	 * pass, siblings will not get enabled without a leader, however a
+	 * leader will enable its siblings, even if those are still on the old
+	 * context.
+	 */
+	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
+		if (event->group_leader == event)
+			continue;
+
+		list_del(&event->migrate_entry);
+		if (event->state >= PERF_EVENT_STATE_OFF)
+			event->state = PERF_EVENT_STATE_INACTIVE;
+		account_event_cpu(event, dst_cpu);
+		perf_install_in_context(dst_ctx, event, dst_cpu);
+		get_ctx(dst_ctx);
+	}
+
+	/*
+	 * Once all the siblings are setup properly, install the group leaders
+	 * to make it go.
+	 */
+	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
+		list_del(&event->migrate_entry);
+		if (event->state >= PERF_EVENT_STATE_OFF)
+			event->state = PERF_EVENT_STATE_INACTIVE;
+		account_event_cpu(event, dst_cpu);
+		perf_install_in_context(dst_ctx, event, dst_cpu);
+		get_ctx(dst_ctx);
+	}
+	mutex_unlock(&dst_ctx->mutex);
+	mutex_unlock(&src_ctx->mutex);
+}
+EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
+
+static void sync_child_event(struct perf_event *child_event)
+{
+	struct perf_event *parent_event = child_event->parent;
+	u64 child_val;
+
+	if (child_event->attr.inherit_stat) {
+		struct task_struct *task = child_event->ctx->task;
+
+		if (task && task != TASK_TOMBSTONE)
+			perf_event_read_event(child_event, task);
+	}
+
+	child_val = perf_event_count(child_event);
+
+	/*
+	 * Add back the child's count to the parent's count:
+	 */
+	atomic64_add(child_val, &parent_event->child_count);
+	atomic64_add(child_event->total_time_enabled,
+		     &parent_event->child_total_time_enabled);
+	atomic64_add(child_event->total_time_running,
+		     &parent_event->child_total_time_running);
+}
+
+static void
+perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
+{
+	struct perf_event *parent_event = event->parent;
+	unsigned long detach_flags = 0;
+
+	if (parent_event) {
+		/*
+		 * Do not destroy the 'original' grouping; because of the
+		 * context switch optimization the original events could've
+		 * ended up in a random child task.
+		 *
+		 * If we were to destroy the original group, all group related
+		 * operations would cease to function properly after this
+		 * random child dies.
+		 *
+		 * Do destroy all inherited groups, we don't care about those
+		 * and being thorough is better.
+		 */
+		detach_flags = DETACH_GROUP | DETACH_CHILD;
+		mutex_lock(&parent_event->child_mutex);
+	}
+
+	perf_remove_from_context(event, detach_flags);
+
+	raw_spin_lock_irq(&ctx->lock);
+	if (event->state > PERF_EVENT_STATE_EXIT)
+		perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
+	raw_spin_unlock_irq(&ctx->lock);
+
+	/*
+	 * Child events can be freed.
+	 */
+	if (parent_event) {
+		mutex_unlock(&parent_event->child_mutex);
+		/*
+		 * Kick perf_poll() for is_event_hup();
+		 */
+		perf_event_wakeup(parent_event);
+		free_event(event);
+		put_event(parent_event);
+		return;
+	}
+
+	/*
+	 * Parent events are governed by their filedesc, retain them.
+	 */
+	perf_event_wakeup(event);
+}
+
+static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
+{
+	struct perf_event_context *child_ctx, *clone_ctx = NULL;
+	struct perf_event *child_event, *next;
+
+	WARN_ON_ONCE(child != current);
+
+	child_ctx = perf_pin_task_context(child, ctxn);
+	if (!child_ctx)
+		return;
+
+	/*
+	 * In order to reduce the amount of tricky in ctx tear-down, we hold
+	 * ctx::mutex over the entire thing. This serializes against almost
+	 * everything that wants to access the ctx.
+	 *
+	 * The exception is sys_perf_event_open() /
+	 * perf_event_create_kernel_count() which does find_get_context()
+	 * without ctx::mutex (it cannot because of the move_group double mutex
+	 * lock thing). See the comments in perf_install_in_context().
+	 */
+	mutex_lock(&child_ctx->mutex);
+
+	/*
+	 * In a single ctx::lock section, de-schedule the events and detach the
+	 * context from the task such that we cannot ever get it scheduled back
+	 * in.
+	 */
+	raw_spin_lock_irq(&child_ctx->lock);
+	task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
+
+	/*
+	 * Now that the context is inactive, destroy the task <-> ctx relation
+	 * and mark the context dead.
+	 */
+	RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
+	put_ctx(child_ctx); /* cannot be last */
+	WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
+	put_task_struct(current); /* cannot be last */
+
+	clone_ctx = unclone_ctx(child_ctx);
+	raw_spin_unlock_irq(&child_ctx->lock);
+
+	if (clone_ctx)
+		put_ctx(clone_ctx);
+
+	/*
+	 * Report the task dead after unscheduling the events so that we
+	 * won't get any samples after PERF_RECORD_EXIT. We can however still
+	 * get a few PERF_RECORD_READ events.
+	 */
+	perf_event_task(child, child_ctx, 0);
+
+	list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
+		perf_event_exit_event(child_event, child_ctx);
+
+	mutex_unlock(&child_ctx->mutex);
+
+	put_ctx(child_ctx);
+}
+
+/*
+ * When a child task exits, feed back event values to parent events.
+ *
+ * Can be called with exec_update_lock held when called from
+ * setup_new_exec().
+ */
+void perf_event_exit_task(struct task_struct *child)
+{
+	struct perf_event *event, *tmp;
+	int ctxn;
+
+	mutex_lock(&child->perf_event_mutex);
+	list_for_each_entry_safe(event, tmp, &child->perf_event_list,
+				 owner_entry) {
+		list_del_init(&event->owner_entry);
+
+		/*
+		 * Ensure the list deletion is visible before we clear
+		 * the owner, closes a race against perf_release() where
+		 * we need to serialize on the owner->perf_event_mutex.
+		 */
+		smp_store_release(&event->owner, NULL);
+	}
+	mutex_unlock(&child->perf_event_mutex);
+
+	for_each_task_context_nr(ctxn)
+		perf_event_exit_task_context(child, ctxn);
+
+	/*
+	 * The perf_event_exit_task_context calls perf_event_task
+	 * with child's task_ctx, which generates EXIT events for
+	 * child contexts and sets child->perf_event_ctxp[] to NULL.
+	 * At this point we need to send EXIT events to cpu contexts.
+	 */
+	perf_event_task(child, NULL, 0);
+}
+
+static void perf_free_event(struct perf_event *event,
+			    struct perf_event_context *ctx)
+{
+	struct perf_event *parent = event->parent;
+
+	if (WARN_ON_ONCE(!parent))
+		return;
+
+	mutex_lock(&parent->child_mutex);
+	list_del_init(&event->child_list);
+	mutex_unlock(&parent->child_mutex);
+
+	put_event(parent);
+
+	raw_spin_lock_irq(&ctx->lock);
+	perf_group_detach(event);
+	list_del_event(event, ctx);
+	raw_spin_unlock_irq(&ctx->lock);
+	free_event(event);
+}
+
+/*
+ * Free a context as created by inheritance by perf_event_init_task() below,
+ * used by fork() in case of fail.
+ *
+ * Even though the task has never lived, the context and events have been
+ * exposed through the child_list, so we must take care tearing it all down.
+ */
+void perf_event_free_task(struct task_struct *task)
+{
+	struct perf_event_context *ctx;
+	struct perf_event *event, *tmp;
+	int ctxn;
+
+	for_each_task_context_nr(ctxn) {
+		ctx = task->perf_event_ctxp[ctxn];
+		if (!ctx)
+			continue;
+
+		mutex_lock(&ctx->mutex);
+		raw_spin_lock_irq(&ctx->lock);
+		/*
+		 * Destroy the task <-> ctx relation and mark the context dead.
+		 *
+		 * This is important because even though the task hasn't been
+		 * exposed yet the context has been (through child_list).
+		 */
+		RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
+		WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
+		put_task_struct(task); /* cannot be last */
+		raw_spin_unlock_irq(&ctx->lock);
+
+		list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
+			perf_free_event(event, ctx);
+
+		mutex_unlock(&ctx->mutex);
+
+		/*
+		 * perf_event_release_kernel() could've stolen some of our
+		 * child events and still have them on its free_list. In that
+		 * case we must wait for these events to have been freed (in
+		 * particular all their references to this task must've been
+		 * dropped).
+		 *
+		 * Without this copy_process() will unconditionally free this
+		 * task (irrespective of its reference count) and
+		 * _free_event()'s put_task_struct(event->hw.target) will be a
+		 * use-after-free.
+		 *
+		 * Wait for all events to drop their context reference.
+		 */
+		wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
+		put_ctx(ctx); /* must be last */
+	}
+}
+
+void perf_event_delayed_put(struct task_struct *task)
+{
+	int ctxn;
+
+	for_each_task_context_nr(ctxn)
+		WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
+}
+
+struct file *perf_event_get(unsigned int fd)
+{
+	struct file *file = fget(fd);
+	if (!file)
+		return ERR_PTR(-EBADF);
+
+	if (file->f_op != &perf_fops) {
+		fput(file);
+		return ERR_PTR(-EBADF);
+	}
+
+	return file;
+}
+
+const struct perf_event *perf_get_event(struct file *file)
+{
+	if (file->f_op != &perf_fops)
+		return ERR_PTR(-EINVAL);
+
+	return file->private_data;
+}
+
+const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
+{
+	if (!event)
+		return ERR_PTR(-EINVAL);
+
+	return &event->attr;
+}
+
+/*
+ * Inherit an event from parent task to child task.
+ *
+ * Returns:
+ *  - valid pointer on success
+ *  - NULL for orphaned events
+ *  - IS_ERR() on error
+ */
+static struct perf_event *
+inherit_event(struct perf_event *parent_event,
+	      struct task_struct *parent,
+	      struct perf_event_context *parent_ctx,
+	      struct task_struct *child,
+	      struct perf_event *group_leader,
+	      struct perf_event_context *child_ctx)
+{
+	enum perf_event_state parent_state = parent_event->state;
+	struct perf_event *child_event;
+	unsigned long flags;
+
+	/*
+	 * Instead of creating recursive hierarchies of events,
+	 * we link inherited events back to the original parent,
+	 * which has a filp for sure, which we use as the reference
+	 * count:
+	 */
+	if (parent_event->parent)
+		parent_event = parent_event->parent;
+
+	child_event = perf_event_alloc(&parent_event->attr,
+					   parent_event->cpu,
+					   child,
+					   group_leader, parent_event,
+					   NULL, NULL, -1);
+	if (IS_ERR(child_event))
+		return child_event;
+
+
+	if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
+	    !child_ctx->task_ctx_data) {
+		struct pmu *pmu = child_event->pmu;
+
+		child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
+		if (!child_ctx->task_ctx_data) {
+			free_event(child_event);
+			return ERR_PTR(-ENOMEM);
+		}
+	}
+
+	/*
+	 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
+	 * must be under the same lock in order to serialize against
+	 * perf_event_release_kernel(), such that either we must observe
+	 * is_orphaned_event() or they will observe us on the child_list.
+	 */
+	mutex_lock(&parent_event->child_mutex);
+	if (is_orphaned_event(parent_event) ||
+	    !atomic_long_inc_not_zero(&parent_event->refcount)) {
+		mutex_unlock(&parent_event->child_mutex);
+		/* task_ctx_data is freed with child_ctx */
+		free_event(child_event);
+		return NULL;
+	}
+
+	get_ctx(child_ctx);
+
+	/*
+	 * Make the child state follow the state of the parent event,
+	 * not its attr.disabled bit.  We hold the parent's mutex,
+	 * so we won't race with perf_event_{en, dis}able_family.
+	 */
+	if (parent_state >= PERF_EVENT_STATE_INACTIVE)
+		child_event->state = PERF_EVENT_STATE_INACTIVE;
+	else
+		child_event->state = PERF_EVENT_STATE_OFF;
+
+	if (parent_event->attr.freq) {
+		u64 sample_period = parent_event->hw.sample_period;
+		struct hw_perf_event *hwc = &child_event->hw;
+
+		hwc->sample_period = sample_period;
+		hwc->last_period   = sample_period;
+
+		local64_set(&hwc->period_left, sample_period);
+	}
+
+	child_event->ctx = child_ctx;
+	child_event->overflow_handler = parent_event->overflow_handler;
+	child_event->overflow_handler_context
+		= parent_event->overflow_handler_context;
+
+	/*
+	 * Precalculate sample_data sizes
+	 */
+	perf_event__header_size(child_event);
+	perf_event__id_header_size(child_event);
+
+	/*
+	 * Link it up in the child's context:
+	 */
+	raw_spin_lock_irqsave(&child_ctx->lock, flags);
+	add_event_to_ctx(child_event, child_ctx);
+	child_event->attach_state |= PERF_ATTACH_CHILD;
+	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
+
+	/*
+	 * Link this into the parent event's child list
+	 */
+	list_add_tail(&child_event->child_list, &parent_event->child_list);
+	mutex_unlock(&parent_event->child_mutex);
+
+	return child_event;
+}
+
+/*
+ * Inherits an event group.
+ *
+ * This will quietly suppress orphaned events; !inherit_event() is not an error.
+ * This matches with perf_event_release_kernel() removing all child events.
+ *
+ * Returns:
+ *  - 0 on success
+ *  - <0 on error
+ */
+static int inherit_group(struct perf_event *parent_event,
+	      struct task_struct *parent,
+	      struct perf_event_context *parent_ctx,
+	      struct task_struct *child,
+	      struct perf_event_context *child_ctx)
+{
+	struct perf_event *leader;
+	struct perf_event *sub;
+	struct perf_event *child_ctr;
+
+	leader = inherit_event(parent_event, parent, parent_ctx,
+				 child, NULL, child_ctx);
+	if (IS_ERR(leader))
+		return PTR_ERR(leader);
+	/*
+	 * @leader can be NULL here because of is_orphaned_event(). In this
+	 * case inherit_event() will create individual events, similar to what
+	 * perf_group_detach() would do anyway.
+	 */
+	for_each_sibling_event(sub, parent_event) {
+		child_ctr = inherit_event(sub, parent, parent_ctx,
+					    child, leader, child_ctx);
+		if (IS_ERR(child_ctr))
+			return PTR_ERR(child_ctr);
+
+		if (sub->aux_event == parent_event && child_ctr &&
+		    !perf_get_aux_event(child_ctr, leader))
+			return -EINVAL;
+	}
+	if (leader)
+		leader->group_generation = parent_event->group_generation;
+	return 0;
+}
+
+/*
+ * Creates the child task context and tries to inherit the event-group.
+ *
+ * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
+ * inherited_all set when we 'fail' to inherit an orphaned event; this is
+ * consistent with perf_event_release_kernel() removing all child events.
+ *
+ * Returns:
+ *  - 0 on success
+ *  - <0 on error
+ */
+static int
+inherit_task_group(struct perf_event *event, struct task_struct *parent,
+		   struct perf_event_context *parent_ctx,
+		   struct task_struct *child, int ctxn,
+		   u64 clone_flags, int *inherited_all)
+{
+	int ret;
+	struct perf_event_context *child_ctx;
+
+	if (!event->attr.inherit ||
+	    (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
+	    /* Do not inherit if sigtrap and signal handlers were cleared. */
+	    (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
+		*inherited_all = 0;
+		return 0;
+	}
+
+	child_ctx = child->perf_event_ctxp[ctxn];
+	if (!child_ctx) {
+		/*
+		 * This is executed from the parent task context, so
+		 * inherit events that have been marked for cloning.
+		 * First allocate and initialize a context for the
+		 * child.
+		 */
+		child_ctx = alloc_perf_context(parent_ctx->pmu, child);
+		if (!child_ctx)
+			return -ENOMEM;
+
+		child->perf_event_ctxp[ctxn] = child_ctx;
+	}
+
+	ret = inherit_group(event, parent, parent_ctx,
+			    child, child_ctx);
+
+	if (ret)
+		*inherited_all = 0;
+
+	return ret;
+}
+
+/*
+ * Initialize the perf_event context in task_struct
+ */
+static int perf_event_init_context(struct task_struct *child, int ctxn,
+				   u64 clone_flags)
+{
+	struct perf_event_context *child_ctx, *parent_ctx;
+	struct perf_event_context *cloned_ctx;
+	struct perf_event *event;
+	struct task_struct *parent = current;
+	int inherited_all = 1;
+	unsigned long flags;
+	int ret = 0;
+
+	if (likely(!parent->perf_event_ctxp[ctxn]))
+		return 0;
+
+	/*
+	 * If the parent's context is a clone, pin it so it won't get
+	 * swapped under us.
+	 */
+	parent_ctx = perf_pin_task_context(parent, ctxn);
+	if (!parent_ctx)
+		return 0;
+
+	/*
+	 * No need to check if parent_ctx != NULL here; since we saw
+	 * it non-NULL earlier, the only reason for it to become NULL
+	 * is if we exit, and since we're currently in the middle of
+	 * a fork we can't be exiting at the same time.
+	 */
+
+	/*
+	 * Lock the parent list. No need to lock the child - not PID
+	 * hashed yet and not running, so nobody can access it.
+	 */
+	mutex_lock(&parent_ctx->mutex);
+
+	/*
+	 * We dont have to disable NMIs - we are only looking at
+	 * the list, not manipulating it:
+	 */
+	perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
+		ret = inherit_task_group(event, parent, parent_ctx,
+					 child, ctxn, clone_flags,
+					 &inherited_all);
+		if (ret)
+			goto out_unlock;
+	}
+
+	/*
+	 * We can't hold ctx->lock when iterating the ->flexible_group list due
+	 * to allocations, but we need to prevent rotation because
+	 * rotate_ctx() will change the list from interrupt context.
+	 */
+	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
+	parent_ctx->rotate_disable = 1;
+	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
+
+	perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
+		ret = inherit_task_group(event, parent, parent_ctx,
+					 child, ctxn, clone_flags,
+					 &inherited_all);
+		if (ret)
+			goto out_unlock;
+	}
+
+	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
+	parent_ctx->rotate_disable = 0;
+
+	child_ctx = child->perf_event_ctxp[ctxn];
+
+	if (child_ctx && inherited_all) {
+		/*
+		 * Mark the child context as a clone of the parent
+		 * context, or of whatever the parent is a clone of.
+		 *
+		 * Note that if the parent is a clone, the holding of
+		 * parent_ctx->lock avoids it from being uncloned.
+		 */
+		cloned_ctx = parent_ctx->parent_ctx;
+		if (cloned_ctx) {
+			child_ctx->parent_ctx = cloned_ctx;
+			child_ctx->parent_gen = parent_ctx->parent_gen;
+		} else {
+			child_ctx->parent_ctx = parent_ctx;
+			child_ctx->parent_gen = parent_ctx->generation;
+		}
+		get_ctx(child_ctx->parent_ctx);
+	}
+
+	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
+out_unlock:
+	mutex_unlock(&parent_ctx->mutex);
+
+	perf_unpin_context(parent_ctx);
+	put_ctx(parent_ctx);
+
+	return ret;
+}
+
+/*
+ * Initialize the perf_event context in task_struct
+ */
+int perf_event_init_task(struct task_struct *child, u64 clone_flags)
+{
+	int ctxn, ret;
+
+	memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
+	mutex_init(&child->perf_event_mutex);
+	INIT_LIST_HEAD(&child->perf_event_list);
+
+	for_each_task_context_nr(ctxn) {
+		ret = perf_event_init_context(child, ctxn, clone_flags);
+		if (ret) {
+			perf_event_free_task(child);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static void __init perf_event_init_all_cpus(void)
+{
+	struct swevent_htable *swhash;
+	int cpu;
+
+	zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
+
+	for_each_possible_cpu(cpu) {
+		swhash = &per_cpu(swevent_htable, cpu);
+		mutex_init(&swhash->hlist_mutex);
+		INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
+
+		INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
+		raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
+
+#ifdef CONFIG_CGROUP_PERF
+		INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
+#endif
+		INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
+	}
+}
+
+static void perf_swevent_init_cpu(unsigned int cpu)
+{
+	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
+
+	mutex_lock(&swhash->hlist_mutex);
+	if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
+		struct swevent_hlist *hlist;
+
+		hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
+		WARN_ON(!hlist);
+		rcu_assign_pointer(swhash->swevent_hlist, hlist);
+	}
+	mutex_unlock(&swhash->hlist_mutex);
+}
+
+#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
+static void __perf_event_exit_context(void *__info)
+{
+	struct perf_event_context *ctx = __info;
+	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+	struct perf_event *event;
+
+	raw_spin_lock(&ctx->lock);
+	ctx_sched_out(ctx, cpuctx, EVENT_TIME);
+	list_for_each_entry(event, &ctx->event_list, event_entry)
+		__perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
+	raw_spin_unlock(&ctx->lock);
+}
+
+static void perf_event_exit_cpu_context(int cpu)
+{
+	struct perf_cpu_context *cpuctx;
+	struct perf_event_context *ctx;
+	struct pmu *pmu;
+
+	mutex_lock(&pmus_lock);
+	list_for_each_entry(pmu, &pmus, entry) {
+		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
+		ctx = &cpuctx->ctx;
+
+		mutex_lock(&ctx->mutex);
+		smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
+		cpuctx->online = 0;
+		mutex_unlock(&ctx->mutex);
+	}
+	cpumask_clear_cpu(cpu, perf_online_mask);
+	mutex_unlock(&pmus_lock);
+}
+#else
+
+static void perf_event_exit_cpu_context(int cpu) { }
+
+#endif
+
+int perf_event_init_cpu(unsigned int cpu)
+{
+	struct perf_cpu_context *cpuctx;
+	struct perf_event_context *ctx;
+	struct pmu *pmu;
+
+	perf_swevent_init_cpu(cpu);
+
+	mutex_lock(&pmus_lock);
+	cpumask_set_cpu(cpu, perf_online_mask);
+	list_for_each_entry(pmu, &pmus, entry) {
+		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
+		ctx = &cpuctx->ctx;
+
+		mutex_lock(&ctx->mutex);
+		cpuctx->online = 1;
+		mutex_unlock(&ctx->mutex);
+	}
+	mutex_unlock(&pmus_lock);
+
+	return 0;
+}
+
+int perf_event_exit_cpu(unsigned int cpu)
+{
+	perf_event_exit_cpu_context(cpu);
+	return 0;
+}
+
+static int
+perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
+{
+	int cpu;
+
+	for_each_online_cpu(cpu)
+		perf_event_exit_cpu(cpu);
+
+	return NOTIFY_OK;
+}
+
+/*
+ * Run the perf reboot notifier at the very last possible moment so that
+ * the generic watchdog code runs as long as possible.
+ */
+static struct notifier_block perf_reboot_notifier = {
+	.notifier_call = perf_reboot,
+	.priority = INT_MIN,
+};
+
+void __init perf_event_init(void)
+{
+	int ret;
+
+	idr_init(&pmu_idr);
+
+	perf_event_init_all_cpus();
+	init_srcu_struct(&pmus_srcu);
+	perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
+	perf_pmu_register(&perf_cpu_clock, NULL, -1);
+	perf_pmu_register(&perf_task_clock, NULL, -1);
+	perf_tp_register();
+	perf_event_init_cpu(smp_processor_id());
+	register_reboot_notifier(&perf_reboot_notifier);
+
+	ret = init_hw_breakpoint();
+	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
+
+	perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
+
+	/*
+	 * Build time assertion that we keep the data_head at the intended
+	 * location.  IOW, validation we got the __reserved[] size right.
+	 */
+	BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
+		     != 1024);
+}
+
+ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
+			      char *page)
+{
+	struct perf_pmu_events_attr *pmu_attr =
+		container_of(attr, struct perf_pmu_events_attr, attr);
+
+	if (pmu_attr->event_str)
+		return sprintf(page, "%s\n", pmu_attr->event_str);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
+
+static int __init perf_event_sysfs_init(void)
+{
+	struct pmu *pmu;
+	int ret;
+
+	mutex_lock(&pmus_lock);
+
+	ret = bus_register(&pmu_bus);
+	if (ret)
+		goto unlock;
+
+	list_for_each_entry(pmu, &pmus, entry) {
+		if (!pmu->name || pmu->type < 0)
+			continue;
+
+		ret = pmu_dev_alloc(pmu);
+		WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
+	}
+	pmu_bus_running = 1;
+	ret = 0;
+
+unlock:
+	mutex_unlock(&pmus_lock);
+
+	return ret;
+}
+device_initcall(perf_event_sysfs_init);
+
+#ifdef CONFIG_CGROUP_PERF
+static struct cgroup_subsys_state *
+perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+	struct perf_cgroup *jc;
+
+	jc = kzalloc(sizeof(*jc), GFP_KERNEL);
+	if (!jc)
+		return ERR_PTR(-ENOMEM);
+
+	jc->info = alloc_percpu(struct perf_cgroup_info);
+	if (!jc->info) {
+		kfree(jc);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return &jc->css;
+}
+
+static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
+{
+	struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
+
+	free_percpu(jc->info);
+	kfree(jc);
+}
+
+static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
+{
+	perf_event_cgroup(css->cgroup);
+	return 0;
+}
+
+static int __perf_cgroup_move(void *info)
+{
+	struct task_struct *task = info;
+	rcu_read_lock();
+	perf_cgroup_switch(task);
+	rcu_read_unlock();
+	return 0;
+}
+
+static void perf_cgroup_attach(struct cgroup_taskset *tset)
+{
+	struct task_struct *task;
+	struct cgroup_subsys_state *css;
+
+	cgroup_taskset_for_each(task, css, tset)
+		task_function_call(task, __perf_cgroup_move, task);
+}
+
+struct cgroup_subsys perf_event_cgrp_subsys = {
+	.css_alloc	= perf_cgroup_css_alloc,
+	.css_free	= perf_cgroup_css_free,
+	.css_online	= perf_cgroup_css_online,
+	.attach		= perf_cgroup_attach,
+	/*
+	 * Implicitly enable on dfl hierarchy so that perf events can
+	 * always be filtered by cgroup2 path as long as perf_event
+	 * controller is not mounted on a legacy hierarchy.
+	 */
+	.implicit_on_dfl = true,
+	.threaded	= true,
+};
+#endif /* CONFIG_CGROUP_PERF */
+
+DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
new file mode 100644
index 000000000..c37977013
--- /dev/null
+++ b/kernel/events/hw_breakpoint.c
@@ -0,0 +1,1051 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2007 Alan Stern
+ * Copyright (C) IBM Corporation, 2009
+ * Copyright (C) 2009, Frederic Weisbecker <fweisbec@gmail.com>
+ *
+ * Thanks to Ingo Molnar for his many suggestions.
+ *
+ * Authors: Alan Stern <stern@rowland.harvard.edu>
+ *          K.Prasad <prasad@linux.vnet.ibm.com>
+ *          Frederic Weisbecker <fweisbec@gmail.com>
+ */
+
+/*
+ * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility,
+ * using the CPU's debug registers.
+ * This file contains the arch-independent routines.
+ */
+
+#include <linux/hw_breakpoint.h>
+
+#include <linux/atomic.h>
+#include <linux/bug.h>
+#include <linux/cpu.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/irqflags.h>
+#include <linux/kdebug.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/percpu-rwsem.h>
+#include <linux/percpu.h>
+#include <linux/rhashtable.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+/*
+ * Datastructure to track the total uses of N slots across tasks or CPUs;
+ * bp_slots_histogram::count[N] is the number of assigned N+1 breakpoint slots.
+ */
+struct bp_slots_histogram {
+#ifdef hw_breakpoint_slots
+	atomic_t count[hw_breakpoint_slots(0)];
+#else
+	atomic_t *count;
+#endif
+};
+
+/*
+ * Per-CPU constraints data.
+ */
+struct bp_cpuinfo {
+	/* Number of pinned CPU breakpoints in a CPU. */
+	unsigned int			cpu_pinned;
+	/* Histogram of pinned task breakpoints in a CPU. */
+	struct bp_slots_histogram	tsk_pinned;
+};
+
+static DEFINE_PER_CPU(struct bp_cpuinfo, bp_cpuinfo[TYPE_MAX]);
+
+static struct bp_cpuinfo *get_bp_info(int cpu, enum bp_type_idx type)
+{
+	return per_cpu_ptr(bp_cpuinfo + type, cpu);
+}
+
+/* Number of pinned CPU breakpoints globally. */
+static struct bp_slots_histogram cpu_pinned[TYPE_MAX];
+/* Number of pinned CPU-independent task breakpoints. */
+static struct bp_slots_histogram tsk_pinned_all[TYPE_MAX];
+
+/* Keep track of the breakpoints attached to tasks */
+static struct rhltable task_bps_ht;
+static const struct rhashtable_params task_bps_ht_params = {
+	.head_offset = offsetof(struct hw_perf_event, bp_list),
+	.key_offset = offsetof(struct hw_perf_event, target),
+	.key_len = sizeof_field(struct hw_perf_event, target),
+	.automatic_shrinking = true,
+};
+
+static bool constraints_initialized __ro_after_init;
+
+/*
+ * Synchronizes accesses to the per-CPU constraints; the locking rules are:
+ *
+ *  1. Atomic updates to bp_cpuinfo::tsk_pinned only require a held read-lock
+ *     (due to bp_slots_histogram::count being atomic, no update are lost).
+ *
+ *  2. Holding a write-lock is required for computations that require a
+ *     stable snapshot of all bp_cpuinfo::tsk_pinned.
+ *
+ *  3. In all other cases, non-atomic accesses require the appropriately held
+ *     lock (read-lock for read-only accesses; write-lock for reads/writes).
+ */
+DEFINE_STATIC_PERCPU_RWSEM(bp_cpuinfo_sem);
+
+/*
+ * Return mutex to serialize accesses to per-task lists in task_bps_ht. Since
+ * rhltable synchronizes concurrent insertions/deletions, independent tasks may
+ * insert/delete concurrently; therefore, a mutex per task is sufficient.
+ *
+ * Uses task_struct::perf_event_mutex, to avoid extending task_struct with a
+ * hw_breakpoint-only mutex, which may be infrequently used. The caveat here is
+ * that hw_breakpoint may contend with per-task perf event list management. The
+ * assumption is that perf usecases involving hw_breakpoints are very unlikely
+ * to result in unnecessary contention.
+ */
+static inline struct mutex *get_task_bps_mutex(struct perf_event *bp)
+{
+	struct task_struct *tsk = bp->hw.target;
+
+	return tsk ? &tsk->perf_event_mutex : NULL;
+}
+
+static struct mutex *bp_constraints_lock(struct perf_event *bp)
+{
+	struct mutex *tsk_mtx = get_task_bps_mutex(bp);
+
+	if (tsk_mtx) {
+		/*
+		 * Fully analogous to the perf_try_init_event() nesting
+		 * argument in the comment near perf_event_ctx_lock_nested();
+		 * this child->perf_event_mutex cannot ever deadlock against
+		 * the parent->perf_event_mutex usage from
+		 * perf_event_task_{en,dis}able().
+		 *
+		 * Specifically, inherited events will never occur on
+		 * ->perf_event_list.
+		 */
+		mutex_lock_nested(tsk_mtx, SINGLE_DEPTH_NESTING);
+		percpu_down_read(&bp_cpuinfo_sem);
+	} else {
+		percpu_down_write(&bp_cpuinfo_sem);
+	}
+
+	return tsk_mtx;
+}
+
+static void bp_constraints_unlock(struct mutex *tsk_mtx)
+{
+	if (tsk_mtx) {
+		percpu_up_read(&bp_cpuinfo_sem);
+		mutex_unlock(tsk_mtx);
+	} else {
+		percpu_up_write(&bp_cpuinfo_sem);
+	}
+}
+
+static bool bp_constraints_is_locked(struct perf_event *bp)
+{
+	struct mutex *tsk_mtx = get_task_bps_mutex(bp);
+
+	return percpu_is_write_locked(&bp_cpuinfo_sem) ||
+	       (tsk_mtx ? mutex_is_locked(tsk_mtx) :
+			  percpu_is_read_locked(&bp_cpuinfo_sem));
+}
+
+static inline void assert_bp_constraints_lock_held(struct perf_event *bp)
+{
+	struct mutex *tsk_mtx = get_task_bps_mutex(bp);
+
+	if (tsk_mtx)
+		lockdep_assert_held(tsk_mtx);
+	lockdep_assert_held(&bp_cpuinfo_sem);
+}
+
+#ifdef hw_breakpoint_slots
+/*
+ * Number of breakpoint slots is constant, and the same for all types.
+ */
+static_assert(hw_breakpoint_slots(TYPE_INST) == hw_breakpoint_slots(TYPE_DATA));
+static inline int hw_breakpoint_slots_cached(int type)	{ return hw_breakpoint_slots(type); }
+static inline int init_breakpoint_slots(void)		{ return 0; }
+#else
+/*
+ * Dynamic number of breakpoint slots.
+ */
+static int __nr_bp_slots[TYPE_MAX] __ro_after_init;
+
+static inline int hw_breakpoint_slots_cached(int type)
+{
+	return __nr_bp_slots[type];
+}
+
+static __init bool
+bp_slots_histogram_alloc(struct bp_slots_histogram *hist, enum bp_type_idx type)
+{
+	hist->count = kcalloc(hw_breakpoint_slots_cached(type), sizeof(*hist->count), GFP_KERNEL);
+	return hist->count;
+}
+
+static __init void bp_slots_histogram_free(struct bp_slots_histogram *hist)
+{
+	kfree(hist->count);
+}
+
+static __init int init_breakpoint_slots(void)
+{
+	int i, cpu, err_cpu;
+
+	for (i = 0; i < TYPE_MAX; i++)
+		__nr_bp_slots[i] = hw_breakpoint_slots(i);
+
+	for_each_possible_cpu(cpu) {
+		for (i = 0; i < TYPE_MAX; i++) {
+			struct bp_cpuinfo *info = get_bp_info(cpu, i);
+
+			if (!bp_slots_histogram_alloc(&info->tsk_pinned, i))
+				goto err;
+		}
+	}
+	for (i = 0; i < TYPE_MAX; i++) {
+		if (!bp_slots_histogram_alloc(&cpu_pinned[i], i))
+			goto err;
+		if (!bp_slots_histogram_alloc(&tsk_pinned_all[i], i))
+			goto err;
+	}
+
+	return 0;
+err:
+	for_each_possible_cpu(err_cpu) {
+		for (i = 0; i < TYPE_MAX; i++)
+			bp_slots_histogram_free(&get_bp_info(err_cpu, i)->tsk_pinned);
+		if (err_cpu == cpu)
+			break;
+	}
+	for (i = 0; i < TYPE_MAX; i++) {
+		bp_slots_histogram_free(&cpu_pinned[i]);
+		bp_slots_histogram_free(&tsk_pinned_all[i]);
+	}
+
+	return -ENOMEM;
+}
+#endif
+
+static inline void
+bp_slots_histogram_add(struct bp_slots_histogram *hist, int old, int val)
+{
+	const int old_idx = old - 1;
+	const int new_idx = old_idx + val;
+
+	if (old_idx >= 0)
+		WARN_ON(atomic_dec_return_relaxed(&hist->count[old_idx]) < 0);
+	if (new_idx >= 0)
+		WARN_ON(atomic_inc_return_relaxed(&hist->count[new_idx]) < 0);
+}
+
+static int
+bp_slots_histogram_max(struct bp_slots_histogram *hist, enum bp_type_idx type)
+{
+	for (int i = hw_breakpoint_slots_cached(type) - 1; i >= 0; i--) {
+		const int count = atomic_read(&hist->count[i]);
+
+		/* Catch unexpected writers; we want a stable snapshot. */
+		ASSERT_EXCLUSIVE_WRITER(hist->count[i]);
+		if (count > 0)
+			return i + 1;
+		WARN(count < 0, "inconsistent breakpoint slots histogram");
+	}
+
+	return 0;
+}
+
+static int
+bp_slots_histogram_max_merge(struct bp_slots_histogram *hist1, struct bp_slots_histogram *hist2,
+			     enum bp_type_idx type)
+{
+	for (int i = hw_breakpoint_slots_cached(type) - 1; i >= 0; i--) {
+		const int count1 = atomic_read(&hist1->count[i]);
+		const int count2 = atomic_read(&hist2->count[i]);
+
+		/* Catch unexpected writers; we want a stable snapshot. */
+		ASSERT_EXCLUSIVE_WRITER(hist1->count[i]);
+		ASSERT_EXCLUSIVE_WRITER(hist2->count[i]);
+		if (count1 + count2 > 0)
+			return i + 1;
+		WARN(count1 < 0, "inconsistent breakpoint slots histogram");
+		WARN(count2 < 0, "inconsistent breakpoint slots histogram");
+	}
+
+	return 0;
+}
+
+#ifndef hw_breakpoint_weight
+static inline int hw_breakpoint_weight(struct perf_event *bp)
+{
+	return 1;
+}
+#endif
+
+static inline enum bp_type_idx find_slot_idx(u64 bp_type)
+{
+	if (bp_type & HW_BREAKPOINT_RW)
+		return TYPE_DATA;
+
+	return TYPE_INST;
+}
+
+/*
+ * Return the maximum number of pinned breakpoints a task has in this CPU.
+ */
+static unsigned int max_task_bp_pinned(int cpu, enum bp_type_idx type)
+{
+	struct bp_slots_histogram *tsk_pinned = &get_bp_info(cpu, type)->tsk_pinned;
+
+	/*
+	 * At this point we want to have acquired the bp_cpuinfo_sem as a
+	 * writer to ensure that there are no concurrent writers in
+	 * toggle_bp_task_slot() to tsk_pinned, and we get a stable snapshot.
+	 */
+	lockdep_assert_held_write(&bp_cpuinfo_sem);
+	return bp_slots_histogram_max_merge(tsk_pinned, &tsk_pinned_all[type], type);
+}
+
+/*
+ * Count the number of breakpoints of the same type and same task.
+ * The given event must be not on the list.
+ *
+ * If @cpu is -1, but the result of task_bp_pinned() is not CPU-independent,
+ * returns a negative value.
+ */
+static int task_bp_pinned(int cpu, struct perf_event *bp, enum bp_type_idx type)
+{
+	struct rhlist_head *head, *pos;
+	struct perf_event *iter;
+	int count = 0;
+
+	/*
+	 * We need a stable snapshot of the per-task breakpoint list.
+	 */
+	assert_bp_constraints_lock_held(bp);
+
+	rcu_read_lock();
+	head = rhltable_lookup(&task_bps_ht, &bp->hw.target, task_bps_ht_params);
+	if (!head)
+		goto out;
+
+	rhl_for_each_entry_rcu(iter, pos, head, hw.bp_list) {
+		if (find_slot_idx(iter->attr.bp_type) != type)
+			continue;
+
+		if (iter->cpu >= 0) {
+			if (cpu == -1) {
+				count = -1;
+				goto out;
+			} else if (cpu != iter->cpu)
+				continue;
+		}
+
+		count += hw_breakpoint_weight(iter);
+	}
+
+out:
+	rcu_read_unlock();
+	return count;
+}
+
+static const struct cpumask *cpumask_of_bp(struct perf_event *bp)
+{
+	if (bp->cpu >= 0)
+		return cpumask_of(bp->cpu);
+	return cpu_possible_mask;
+}
+
+/*
+ * Returns the max pinned breakpoint slots in a given
+ * CPU (cpu > -1) or across all of them (cpu = -1).
+ */
+static int
+max_bp_pinned_slots(struct perf_event *bp, enum bp_type_idx type)
+{
+	const struct cpumask *cpumask = cpumask_of_bp(bp);
+	int pinned_slots = 0;
+	int cpu;
+
+	if (bp->hw.target && bp->cpu < 0) {
+		int max_pinned = task_bp_pinned(-1, bp, type);
+
+		if (max_pinned >= 0) {
+			/*
+			 * Fast path: task_bp_pinned() is CPU-independent and
+			 * returns the same value for any CPU.
+			 */
+			max_pinned += bp_slots_histogram_max(&cpu_pinned[type], type);
+			return max_pinned;
+		}
+	}
+
+	for_each_cpu(cpu, cpumask) {
+		struct bp_cpuinfo *info = get_bp_info(cpu, type);
+		int nr;
+
+		nr = info->cpu_pinned;
+		if (!bp->hw.target)
+			nr += max_task_bp_pinned(cpu, type);
+		else
+			nr += task_bp_pinned(cpu, bp, type);
+
+		pinned_slots = max(nr, pinned_slots);
+	}
+
+	return pinned_slots;
+}
+
+/*
+ * Add/remove the given breakpoint in our constraint table
+ */
+static int
+toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type, int weight)
+{
+	int cpu, next_tsk_pinned;
+
+	if (!enable)
+		weight = -weight;
+
+	if (!bp->hw.target) {
+		/*
+		 * Update the pinned CPU slots, in per-CPU bp_cpuinfo and in the
+		 * global histogram.
+		 */
+		struct bp_cpuinfo *info = get_bp_info(bp->cpu, type);
+
+		lockdep_assert_held_write(&bp_cpuinfo_sem);
+		bp_slots_histogram_add(&cpu_pinned[type], info->cpu_pinned, weight);
+		info->cpu_pinned += weight;
+		return 0;
+	}
+
+	/*
+	 * If bp->hw.target, tsk_pinned is only modified, but not used
+	 * otherwise. We can permit concurrent updates as long as there are no
+	 * other uses: having acquired bp_cpuinfo_sem as a reader allows
+	 * concurrent updates here. Uses of tsk_pinned will require acquiring
+	 * bp_cpuinfo_sem as a writer to stabilize tsk_pinned's value.
+	 */
+	lockdep_assert_held_read(&bp_cpuinfo_sem);
+
+	/*
+	 * Update the pinned task slots, in per-CPU bp_cpuinfo and in the global
+	 * histogram. We need to take care of 4 cases:
+	 *
+	 *  1. This breakpoint targets all CPUs (cpu < 0), and there may only
+	 *     exist other task breakpoints targeting all CPUs. In this case we
+	 *     can simply update the global slots histogram.
+	 *
+	 *  2. This breakpoint targets a specific CPU (cpu >= 0), but there may
+	 *     only exist other task breakpoints targeting all CPUs.
+	 *
+	 *     a. On enable: remove the existing breakpoints from the global
+	 *        slots histogram and use the per-CPU histogram.
+	 *
+	 *     b. On disable: re-insert the existing breakpoints into the global
+	 *        slots histogram and remove from per-CPU histogram.
+	 *
+	 *  3. Some other existing task breakpoints target specific CPUs. Only
+	 *     update the per-CPU slots histogram.
+	 */
+
+	if (!enable) {
+		/*
+		 * Remove before updating histograms so we can determine if this
+		 * was the last task breakpoint for a specific CPU.
+		 */
+		int ret = rhltable_remove(&task_bps_ht, &bp->hw.bp_list, task_bps_ht_params);
+
+		if (ret)
+			return ret;
+	}
+	/*
+	 * Note: If !enable, next_tsk_pinned will not count the to-be-removed breakpoint.
+	 */
+	next_tsk_pinned = task_bp_pinned(-1, bp, type);
+
+	if (next_tsk_pinned >= 0) {
+		if (bp->cpu < 0) { /* Case 1: fast path */
+			if (!enable)
+				next_tsk_pinned += hw_breakpoint_weight(bp);
+			bp_slots_histogram_add(&tsk_pinned_all[type], next_tsk_pinned, weight);
+		} else if (enable) { /* Case 2.a: slow path */
+			/* Add existing to per-CPU histograms. */
+			for_each_possible_cpu(cpu) {
+				bp_slots_histogram_add(&get_bp_info(cpu, type)->tsk_pinned,
+						       0, next_tsk_pinned);
+			}
+			/* Add this first CPU-pinned task breakpoint. */
+			bp_slots_histogram_add(&get_bp_info(bp->cpu, type)->tsk_pinned,
+					       next_tsk_pinned, weight);
+			/* Rebalance global task pinned histogram. */
+			bp_slots_histogram_add(&tsk_pinned_all[type], next_tsk_pinned,
+					       -next_tsk_pinned);
+		} else { /* Case 2.b: slow path */
+			/* Remove this last CPU-pinned task breakpoint. */
+			bp_slots_histogram_add(&get_bp_info(bp->cpu, type)->tsk_pinned,
+					       next_tsk_pinned + hw_breakpoint_weight(bp), weight);
+			/* Remove all from per-CPU histograms. */
+			for_each_possible_cpu(cpu) {
+				bp_slots_histogram_add(&get_bp_info(cpu, type)->tsk_pinned,
+						       next_tsk_pinned, -next_tsk_pinned);
+			}
+			/* Rebalance global task pinned histogram. */
+			bp_slots_histogram_add(&tsk_pinned_all[type], 0, next_tsk_pinned);
+		}
+	} else { /* Case 3: slow path */
+		const struct cpumask *cpumask = cpumask_of_bp(bp);
+
+		for_each_cpu(cpu, cpumask) {
+			next_tsk_pinned = task_bp_pinned(cpu, bp, type);
+			if (!enable)
+				next_tsk_pinned += hw_breakpoint_weight(bp);
+			bp_slots_histogram_add(&get_bp_info(cpu, type)->tsk_pinned,
+					       next_tsk_pinned, weight);
+		}
+	}
+
+	/*
+	 * Readers want a stable snapshot of the per-task breakpoint list.
+	 */
+	assert_bp_constraints_lock_held(bp);
+
+	if (enable)
+		return rhltable_insert(&task_bps_ht, &bp->hw.bp_list, task_bps_ht_params);
+
+	return 0;
+}
+
+__weak int arch_reserve_bp_slot(struct perf_event *bp)
+{
+	return 0;
+}
+
+__weak void arch_release_bp_slot(struct perf_event *bp)
+{
+}
+
+/*
+ * Function to perform processor-specific cleanup during unregistration
+ */
+__weak void arch_unregister_hw_breakpoint(struct perf_event *bp)
+{
+	/*
+	 * A weak stub function here for those archs that don't define
+	 * it inside arch/.../kernel/hw_breakpoint.c
+	 */
+}
+
+/*
+ * Constraints to check before allowing this new breakpoint counter.
+ *
+ * Note: Flexible breakpoints are currently unimplemented, but outlined in the
+ * below algorithm for completeness.  The implementation treats flexible as
+ * pinned due to no guarantee that we currently always schedule flexible events
+ * before a pinned event in a same CPU.
+ *
+ *  == Non-pinned counter == (Considered as pinned for now)
+ *
+ *   - If attached to a single cpu, check:
+ *
+ *       (per_cpu(info->flexible, cpu) || (per_cpu(info->cpu_pinned, cpu)
+ *           + max(per_cpu(info->tsk_pinned, cpu)))) < HBP_NUM
+ *
+ *       -> If there are already non-pinned counters in this cpu, it means
+ *          there is already a free slot for them.
+ *          Otherwise, we check that the maximum number of per task
+ *          breakpoints (for this cpu) plus the number of per cpu breakpoint
+ *          (for this cpu) doesn't cover every registers.
+ *
+ *   - If attached to every cpus, check:
+ *
+ *       (per_cpu(info->flexible, *) || (max(per_cpu(info->cpu_pinned, *))
+ *           + max(per_cpu(info->tsk_pinned, *)))) < HBP_NUM
+ *
+ *       -> This is roughly the same, except we check the number of per cpu
+ *          bp for every cpu and we keep the max one. Same for the per tasks
+ *          breakpoints.
+ *
+ *
+ * == Pinned counter ==
+ *
+ *   - If attached to a single cpu, check:
+ *
+ *       ((per_cpu(info->flexible, cpu) > 1) + per_cpu(info->cpu_pinned, cpu)
+ *            + max(per_cpu(info->tsk_pinned, cpu))) < HBP_NUM
+ *
+ *       -> Same checks as before. But now the info->flexible, if any, must keep
+ *          one register at least (or they will never be fed).
+ *
+ *   - If attached to every cpus, check:
+ *
+ *       ((per_cpu(info->flexible, *) > 1) + max(per_cpu(info->cpu_pinned, *))
+ *            + max(per_cpu(info->tsk_pinned, *))) < HBP_NUM
+ */
+static int __reserve_bp_slot(struct perf_event *bp, u64 bp_type)
+{
+	enum bp_type_idx type;
+	int max_pinned_slots;
+	int weight;
+	int ret;
+
+	/* We couldn't initialize breakpoint constraints on boot */
+	if (!constraints_initialized)
+		return -ENOMEM;
+
+	/* Basic checks */
+	if (bp_type == HW_BREAKPOINT_EMPTY ||
+	    bp_type == HW_BREAKPOINT_INVALID)
+		return -EINVAL;
+
+	type = find_slot_idx(bp_type);
+	weight = hw_breakpoint_weight(bp);
+
+	/* Check if this new breakpoint can be satisfied across all CPUs. */
+	max_pinned_slots = max_bp_pinned_slots(bp, type) + weight;
+	if (max_pinned_slots > hw_breakpoint_slots_cached(type))
+		return -ENOSPC;
+
+	ret = arch_reserve_bp_slot(bp);
+	if (ret)
+		return ret;
+
+	return toggle_bp_slot(bp, true, type, weight);
+}
+
+int reserve_bp_slot(struct perf_event *bp)
+{
+	struct mutex *mtx = bp_constraints_lock(bp);
+	int ret = __reserve_bp_slot(bp, bp->attr.bp_type);
+
+	bp_constraints_unlock(mtx);
+	return ret;
+}
+
+static void __release_bp_slot(struct perf_event *bp, u64 bp_type)
+{
+	enum bp_type_idx type;
+	int weight;
+
+	arch_release_bp_slot(bp);
+
+	type = find_slot_idx(bp_type);
+	weight = hw_breakpoint_weight(bp);
+	WARN_ON(toggle_bp_slot(bp, false, type, weight));
+}
+
+void release_bp_slot(struct perf_event *bp)
+{
+	struct mutex *mtx = bp_constraints_lock(bp);
+
+	arch_unregister_hw_breakpoint(bp);
+	__release_bp_slot(bp, bp->attr.bp_type);
+	bp_constraints_unlock(mtx);
+}
+
+static int __modify_bp_slot(struct perf_event *bp, u64 old_type, u64 new_type)
+{
+	int err;
+
+	__release_bp_slot(bp, old_type);
+
+	err = __reserve_bp_slot(bp, new_type);
+	if (err) {
+		/*
+		 * Reserve the old_type slot back in case
+		 * there's no space for the new type.
+		 *
+		 * This must succeed, because we just released
+		 * the old_type slot in the __release_bp_slot
+		 * call above. If not, something is broken.
+		 */
+		WARN_ON(__reserve_bp_slot(bp, old_type));
+	}
+
+	return err;
+}
+
+static int modify_bp_slot(struct perf_event *bp, u64 old_type, u64 new_type)
+{
+	struct mutex *mtx = bp_constraints_lock(bp);
+	int ret = __modify_bp_slot(bp, old_type, new_type);
+
+	bp_constraints_unlock(mtx);
+	return ret;
+}
+
+/*
+ * Allow the kernel debugger to reserve breakpoint slots without
+ * taking a lock using the dbg_* variant of for the reserve and
+ * release breakpoint slots.
+ */
+int dbg_reserve_bp_slot(struct perf_event *bp)
+{
+	int ret;
+
+	if (bp_constraints_is_locked(bp))
+		return -1;
+
+	/* Locks aren't held; disable lockdep assert checking. */
+	lockdep_off();
+	ret = __reserve_bp_slot(bp, bp->attr.bp_type);
+	lockdep_on();
+
+	return ret;
+}
+
+int dbg_release_bp_slot(struct perf_event *bp)
+{
+	if (bp_constraints_is_locked(bp))
+		return -1;
+
+	/* Locks aren't held; disable lockdep assert checking. */
+	lockdep_off();
+	__release_bp_slot(bp, bp->attr.bp_type);
+	lockdep_on();
+
+	return 0;
+}
+
+static int hw_breakpoint_parse(struct perf_event *bp,
+			       const struct perf_event_attr *attr,
+			       struct arch_hw_breakpoint *hw)
+{
+	int err;
+
+	err = hw_breakpoint_arch_parse(bp, attr, hw);
+	if (err)
+		return err;
+
+	if (arch_check_bp_in_kernelspace(hw)) {
+		if (attr->exclude_kernel)
+			return -EINVAL;
+		/*
+		 * Don't let unprivileged users set a breakpoint in the trap
+		 * path to avoid trap recursion attacks.
+		 */
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+	}
+
+	return 0;
+}
+
+int register_perf_hw_breakpoint(struct perf_event *bp)
+{
+	struct arch_hw_breakpoint hw = { };
+	int err;
+
+	err = reserve_bp_slot(bp);
+	if (err)
+		return err;
+
+	err = hw_breakpoint_parse(bp, &bp->attr, &hw);
+	if (err) {
+		release_bp_slot(bp);
+		return err;
+	}
+
+	bp->hw.info = hw;
+
+	return 0;
+}
+
+/**
+ * register_user_hw_breakpoint - register a hardware breakpoint for user space
+ * @attr: breakpoint attributes
+ * @triggered: callback to trigger when we hit the breakpoint
+ * @context: context data could be used in the triggered callback
+ * @tsk: pointer to 'task_struct' of the process to which the address belongs
+ */
+struct perf_event *
+register_user_hw_breakpoint(struct perf_event_attr *attr,
+			    perf_overflow_handler_t triggered,
+			    void *context,
+			    struct task_struct *tsk)
+{
+	return perf_event_create_kernel_counter(attr, -1, tsk, triggered,
+						context);
+}
+EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);
+
+static void hw_breakpoint_copy_attr(struct perf_event_attr *to,
+				    struct perf_event_attr *from)
+{
+	to->bp_addr = from->bp_addr;
+	to->bp_type = from->bp_type;
+	to->bp_len  = from->bp_len;
+	to->disabled = from->disabled;
+}
+
+int
+modify_user_hw_breakpoint_check(struct perf_event *bp, struct perf_event_attr *attr,
+			        bool check)
+{
+	struct arch_hw_breakpoint hw = { };
+	int err;
+
+	err = hw_breakpoint_parse(bp, attr, &hw);
+	if (err)
+		return err;
+
+	if (check) {
+		struct perf_event_attr old_attr;
+
+		old_attr = bp->attr;
+		hw_breakpoint_copy_attr(&old_attr, attr);
+		if (memcmp(&old_attr, attr, sizeof(*attr)))
+			return -EINVAL;
+	}
+
+	if (bp->attr.bp_type != attr->bp_type) {
+		err = modify_bp_slot(bp, bp->attr.bp_type, attr->bp_type);
+		if (err)
+			return err;
+	}
+
+	hw_breakpoint_copy_attr(&bp->attr, attr);
+	bp->hw.info = hw;
+
+	return 0;
+}
+
+/**
+ * modify_user_hw_breakpoint - modify a user-space hardware breakpoint
+ * @bp: the breakpoint structure to modify
+ * @attr: new breakpoint attributes
+ */
+int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr)
+{
+	int err;
+
+	/*
+	 * modify_user_hw_breakpoint can be invoked with IRQs disabled and hence it
+	 * will not be possible to raise IPIs that invoke __perf_event_disable.
+	 * So call the function directly after making sure we are targeting the
+	 * current task.
+	 */
+	if (irqs_disabled() && bp->ctx && bp->ctx->task == current)
+		perf_event_disable_local(bp);
+	else
+		perf_event_disable(bp);
+
+	err = modify_user_hw_breakpoint_check(bp, attr, false);
+
+	if (!bp->attr.disabled)
+		perf_event_enable(bp);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);
+
+/**
+ * unregister_hw_breakpoint - unregister a user-space hardware breakpoint
+ * @bp: the breakpoint structure to unregister
+ */
+void unregister_hw_breakpoint(struct perf_event *bp)
+{
+	if (!bp)
+		return;
+	perf_event_release_kernel(bp);
+}
+EXPORT_SYMBOL_GPL(unregister_hw_breakpoint);
+
+/**
+ * register_wide_hw_breakpoint - register a wide breakpoint in the kernel
+ * @attr: breakpoint attributes
+ * @triggered: callback to trigger when we hit the breakpoint
+ * @context: context data could be used in the triggered callback
+ *
+ * @return a set of per_cpu pointers to perf events
+ */
+struct perf_event * __percpu *
+register_wide_hw_breakpoint(struct perf_event_attr *attr,
+			    perf_overflow_handler_t triggered,
+			    void *context)
+{
+	struct perf_event * __percpu *cpu_events, *bp;
+	long err = 0;
+	int cpu;
+
+	cpu_events = alloc_percpu(typeof(*cpu_events));
+	if (!cpu_events)
+		return (void __percpu __force *)ERR_PTR(-ENOMEM);
+
+	cpus_read_lock();
+	for_each_online_cpu(cpu) {
+		bp = perf_event_create_kernel_counter(attr, cpu, NULL,
+						      triggered, context);
+		if (IS_ERR(bp)) {
+			err = PTR_ERR(bp);
+			break;
+		}
+
+		per_cpu(*cpu_events, cpu) = bp;
+	}
+	cpus_read_unlock();
+
+	if (likely(!err))
+		return cpu_events;
+
+	unregister_wide_hw_breakpoint(cpu_events);
+	return (void __percpu __force *)ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(register_wide_hw_breakpoint);
+
+/**
+ * unregister_wide_hw_breakpoint - unregister a wide breakpoint in the kernel
+ * @cpu_events: the per cpu set of events to unregister
+ */
+void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		unregister_hw_breakpoint(per_cpu(*cpu_events, cpu));
+
+	free_percpu(cpu_events);
+}
+EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint);
+
+/**
+ * hw_breakpoint_is_used - check if breakpoints are currently used
+ *
+ * Returns: true if breakpoints are used, false otherwise.
+ */
+bool hw_breakpoint_is_used(void)
+{
+	int cpu;
+
+	if (!constraints_initialized)
+		return false;
+
+	for_each_possible_cpu(cpu) {
+		for (int type = 0; type < TYPE_MAX; ++type) {
+			struct bp_cpuinfo *info = get_bp_info(cpu, type);
+
+			if (info->cpu_pinned)
+				return true;
+
+			for (int slot = 0; slot < hw_breakpoint_slots_cached(type); ++slot) {
+				if (atomic_read(&info->tsk_pinned.count[slot]))
+					return true;
+			}
+		}
+	}
+
+	for (int type = 0; type < TYPE_MAX; ++type) {
+		for (int slot = 0; slot < hw_breakpoint_slots_cached(type); ++slot) {
+			/*
+			 * Warn, because if there are CPU pinned counters,
+			 * should never get here; bp_cpuinfo::cpu_pinned should
+			 * be consistent with the global cpu_pinned histogram.
+			 */
+			if (WARN_ON(atomic_read(&cpu_pinned[type].count[slot])))
+				return true;
+
+			if (atomic_read(&tsk_pinned_all[type].count[slot]))
+				return true;
+		}
+	}
+
+	return false;
+}
+
+static struct notifier_block hw_breakpoint_exceptions_nb = {
+	.notifier_call = hw_breakpoint_exceptions_notify,
+	/* we need to be notified first */
+	.priority = 0x7fffffff
+};
+
+static void bp_perf_event_destroy(struct perf_event *event)
+{
+	release_bp_slot(event);
+}
+
+static int hw_breakpoint_event_init(struct perf_event *bp)
+{
+	int err;
+
+	if (bp->attr.type != PERF_TYPE_BREAKPOINT)
+		return -ENOENT;
+
+	/*
+	 * no branch sampling for breakpoint events
+	 */
+	if (has_branch_stack(bp))
+		return -EOPNOTSUPP;
+
+	err = register_perf_hw_breakpoint(bp);
+	if (err)
+		return err;
+
+	bp->destroy = bp_perf_event_destroy;
+
+	return 0;
+}
+
+static int hw_breakpoint_add(struct perf_event *bp, int flags)
+{
+	if (!(flags & PERF_EF_START))
+		bp->hw.state = PERF_HES_STOPPED;
+
+	if (is_sampling_event(bp)) {
+		bp->hw.last_period = bp->hw.sample_period;
+		perf_swevent_set_period(bp);
+	}
+
+	return arch_install_hw_breakpoint(bp);
+}
+
+static void hw_breakpoint_del(struct perf_event *bp, int flags)
+{
+	arch_uninstall_hw_breakpoint(bp);
+}
+
+static void hw_breakpoint_start(struct perf_event *bp, int flags)
+{
+	bp->hw.state = 0;
+}
+
+static void hw_breakpoint_stop(struct perf_event *bp, int flags)
+{
+	bp->hw.state = PERF_HES_STOPPED;
+}
+
+static struct pmu perf_breakpoint = {
+	.task_ctx_nr	= perf_sw_context, /* could eventually get its own */
+
+	.event_init	= hw_breakpoint_event_init,
+	.add		= hw_breakpoint_add,
+	.del		= hw_breakpoint_del,
+	.start		= hw_breakpoint_start,
+	.stop		= hw_breakpoint_stop,
+	.read		= hw_breakpoint_pmu_read,
+};
+
+int __init init_hw_breakpoint(void)
+{
+	int ret;
+
+	ret = rhltable_init(&task_bps_ht, &task_bps_ht_params);
+	if (ret)
+		return ret;
+
+	ret = init_breakpoint_slots();
+	if (ret)
+		return ret;
+
+	constraints_initialized = true;
+
+	perf_pmu_register(&perf_breakpoint, "breakpoint", PERF_TYPE_BREAKPOINT);
+
+	return register_die_notifier(&hw_breakpoint_exceptions_nb);
+}
diff --git a/kernel/events/hw_breakpoint_test.c b/kernel/events/hw_breakpoint_test.c
new file mode 100644
index 000000000..c57610f52
--- /dev/null
+++ b/kernel/events/hw_breakpoint_test.c
@@ -0,0 +1,333 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit test for hw_breakpoint constraints accounting logic.
+ *
+ * Copyright (C) 2022, Google LLC.
+ */
+
+#include <kunit/test.h>
+#include <linux/cpumask.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/kthread.h>
+#include <linux/perf_event.h>
+#include <asm/hw_breakpoint.h>
+
+#define TEST_REQUIRES_BP_SLOTS(test, slots)						\
+	do {										\
+		if ((slots) > get_test_bp_slots()) {					\
+			kunit_skip((test), "Requires breakpoint slots: %d > %d", slots,	\
+				   get_test_bp_slots());				\
+		}									\
+	} while (0)
+
+#define TEST_EXPECT_NOSPC(expr) KUNIT_EXPECT_EQ(test, -ENOSPC, PTR_ERR(expr))
+
+#define MAX_TEST_BREAKPOINTS 512
+
+static char break_vars[MAX_TEST_BREAKPOINTS];
+static struct perf_event *test_bps[MAX_TEST_BREAKPOINTS];
+static struct task_struct *__other_task;
+
+static struct perf_event *register_test_bp(int cpu, struct task_struct *tsk, int idx)
+{
+	struct perf_event_attr attr = {};
+
+	if (WARN_ON(idx < 0 || idx >= MAX_TEST_BREAKPOINTS))
+		return NULL;
+
+	hw_breakpoint_init(&attr);
+	attr.bp_addr = (unsigned long)&break_vars[idx];
+	attr.bp_len = HW_BREAKPOINT_LEN_1;
+	attr.bp_type = HW_BREAKPOINT_RW;
+	return perf_event_create_kernel_counter(&attr, cpu, tsk, NULL, NULL);
+}
+
+static void unregister_test_bp(struct perf_event **bp)
+{
+	if (WARN_ON(IS_ERR(*bp)))
+		return;
+	if (WARN_ON(!*bp))
+		return;
+	unregister_hw_breakpoint(*bp);
+	*bp = NULL;
+}
+
+static int get_test_bp_slots(void)
+{
+	static int slots;
+
+	if (!slots)
+		slots = hw_breakpoint_slots(TYPE_DATA);
+
+	return slots;
+}
+
+static void fill_one_bp_slot(struct kunit *test, int *id, int cpu, struct task_struct *tsk)
+{
+	struct perf_event *bp = register_test_bp(cpu, tsk, *id);
+
+	KUNIT_ASSERT_NOT_NULL(test, bp);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(bp));
+	KUNIT_ASSERT_NULL(test, test_bps[*id]);
+	test_bps[(*id)++] = bp;
+}
+
+/*
+ * Fills up the given @cpu/@tsk with breakpoints, only leaving @skip slots free.
+ *
+ * Returns true if this can be called again, continuing at @id.
+ */
+static bool fill_bp_slots(struct kunit *test, int *id, int cpu, struct task_struct *tsk, int skip)
+{
+	for (int i = 0; i < get_test_bp_slots() - skip; ++i)
+		fill_one_bp_slot(test, id, cpu, tsk);
+
+	return *id + get_test_bp_slots() <= MAX_TEST_BREAKPOINTS;
+}
+
+static int dummy_kthread(void *arg)
+{
+	return 0;
+}
+
+static struct task_struct *get_other_task(struct kunit *test)
+{
+	struct task_struct *tsk;
+
+	if (__other_task)
+		return __other_task;
+
+	tsk = kthread_create(dummy_kthread, NULL, "hw_breakpoint_dummy_task");
+	KUNIT_ASSERT_FALSE(test, IS_ERR(tsk));
+	__other_task = tsk;
+	return __other_task;
+}
+
+static int get_test_cpu(int num)
+{
+	int cpu;
+
+	WARN_ON(num < 0);
+
+	for_each_online_cpu(cpu) {
+		if (num-- <= 0)
+			break;
+	}
+
+	return cpu;
+}
+
+/* ===== Test cases ===== */
+
+static void test_one_cpu(struct kunit *test)
+{
+	int idx = 0;
+
+	fill_bp_slots(test, &idx, get_test_cpu(0), NULL, 0);
+	TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
+}
+
+static void test_many_cpus(struct kunit *test)
+{
+	int idx = 0;
+	int cpu;
+
+	/* Test that CPUs are independent. */
+	for_each_online_cpu(cpu) {
+		bool do_continue = fill_bp_slots(test, &idx, cpu, NULL, 0);
+
+		TEST_EXPECT_NOSPC(register_test_bp(cpu, NULL, idx));
+		if (!do_continue)
+			break;
+	}
+}
+
+static void test_one_task_on_all_cpus(struct kunit *test)
+{
+	int idx = 0;
+
+	fill_bp_slots(test, &idx, -1, current, 0);
+	TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
+	/* Remove one and adding back CPU-target should work. */
+	unregister_test_bp(&test_bps[0]);
+	fill_one_bp_slot(test, &idx, get_test_cpu(0), NULL);
+}
+
+static void test_two_tasks_on_all_cpus(struct kunit *test)
+{
+	int idx = 0;
+
+	/* Test that tasks are independent. */
+	fill_bp_slots(test, &idx, -1, current, 0);
+	fill_bp_slots(test, &idx, -1, get_other_task(test), 0);
+
+	TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(-1, get_other_task(test), idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), get_other_task(test), idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
+	/* Remove one from first task and adding back CPU-target should not work. */
+	unregister_test_bp(&test_bps[0]);
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
+}
+
+static void test_one_task_on_one_cpu(struct kunit *test)
+{
+	int idx = 0;
+
+	fill_bp_slots(test, &idx, get_test_cpu(0), current, 0);
+	TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
+	/*
+	 * Remove one and adding back CPU-target should work; this case is
+	 * special vs. above because the task's constraints are CPU-dependent.
+	 */
+	unregister_test_bp(&test_bps[0]);
+	fill_one_bp_slot(test, &idx, get_test_cpu(0), NULL);
+}
+
+static void test_one_task_mixed(struct kunit *test)
+{
+	int idx = 0;
+
+	TEST_REQUIRES_BP_SLOTS(test, 3);
+
+	fill_one_bp_slot(test, &idx, get_test_cpu(0), current);
+	fill_bp_slots(test, &idx, -1, current, 1);
+	TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
+
+	/* Transition from CPU-dependent pinned count to CPU-independent. */
+	unregister_test_bp(&test_bps[0]);
+	unregister_test_bp(&test_bps[1]);
+	fill_one_bp_slot(test, &idx, get_test_cpu(0), NULL);
+	fill_one_bp_slot(test, &idx, get_test_cpu(0), NULL);
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
+}
+
+static void test_two_tasks_on_one_cpu(struct kunit *test)
+{
+	int idx = 0;
+
+	fill_bp_slots(test, &idx, get_test_cpu(0), current, 0);
+	fill_bp_slots(test, &idx, get_test_cpu(0), get_other_task(test), 0);
+
+	TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(-1, get_other_task(test), idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), get_other_task(test), idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
+	/* Can still create breakpoints on some other CPU. */
+	fill_bp_slots(test, &idx, get_test_cpu(1), NULL, 0);
+}
+
+static void test_two_tasks_on_one_all_cpus(struct kunit *test)
+{
+	int idx = 0;
+
+	fill_bp_slots(test, &idx, get_test_cpu(0), current, 0);
+	fill_bp_slots(test, &idx, -1, get_other_task(test), 0);
+
+	TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(-1, get_other_task(test), idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), get_other_task(test), idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
+	/* Cannot create breakpoints on some other CPU either. */
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(1), NULL, idx));
+}
+
+static void test_task_on_all_and_one_cpu(struct kunit *test)
+{
+	int tsk_on_cpu_idx, cpu_idx;
+	int idx = 0;
+
+	TEST_REQUIRES_BP_SLOTS(test, 3);
+
+	fill_bp_slots(test, &idx, -1, current, 2);
+	/* Transitioning from only all CPU breakpoints to mixed. */
+	tsk_on_cpu_idx = idx;
+	fill_one_bp_slot(test, &idx, get_test_cpu(0), current);
+	fill_one_bp_slot(test, &idx, -1, current);
+
+	TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
+
+	/* We should still be able to use up another CPU's slots. */
+	cpu_idx = idx;
+	fill_one_bp_slot(test, &idx, get_test_cpu(1), NULL);
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(1), NULL, idx));
+
+	/* Transitioning back to task target on all CPUs. */
+	unregister_test_bp(&test_bps[tsk_on_cpu_idx]);
+	/* Still have a CPU target breakpoint in get_test_cpu(1). */
+	TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
+	/* Remove it and try again. */
+	unregister_test_bp(&test_bps[cpu_idx]);
+	fill_one_bp_slot(test, &idx, -1, current);
+
+	TEST_EXPECT_NOSPC(register_test_bp(-1, current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), current, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(0), NULL, idx));
+	TEST_EXPECT_NOSPC(register_test_bp(get_test_cpu(1), NULL, idx));
+}
+
+static struct kunit_case hw_breakpoint_test_cases[] = {
+	KUNIT_CASE(test_one_cpu),
+	KUNIT_CASE(test_many_cpus),
+	KUNIT_CASE(test_one_task_on_all_cpus),
+	KUNIT_CASE(test_two_tasks_on_all_cpus),
+	KUNIT_CASE(test_one_task_on_one_cpu),
+	KUNIT_CASE(test_one_task_mixed),
+	KUNIT_CASE(test_two_tasks_on_one_cpu),
+	KUNIT_CASE(test_two_tasks_on_one_all_cpus),
+	KUNIT_CASE(test_task_on_all_and_one_cpu),
+	{},
+};
+
+static int test_init(struct kunit *test)
+{
+	/* Most test cases want 2 distinct CPUs. */
+	if (num_online_cpus() < 2)
+		kunit_skip(test, "not enough cpus");
+
+	/* Want the system to not use breakpoints elsewhere. */
+	if (hw_breakpoint_is_used())
+		kunit_skip(test, "hw breakpoint already in use");
+
+	return 0;
+}
+
+static void test_exit(struct kunit *test)
+{
+	for (int i = 0; i < MAX_TEST_BREAKPOINTS; ++i) {
+		if (test_bps[i])
+			unregister_test_bp(&test_bps[i]);
+	}
+
+	if (__other_task) {
+		kthread_stop(__other_task);
+		__other_task = NULL;
+	}
+
+	/* Verify that internal state agrees that no breakpoints are in use. */
+	KUNIT_EXPECT_FALSE(test, hw_breakpoint_is_used());
+}
+
+static struct kunit_suite hw_breakpoint_test_suite = {
+	.name = "hw_breakpoint",
+	.test_cases = hw_breakpoint_test_cases,
+	.init = test_init,
+	.exit = test_exit,
+};
+
+kunit_test_suites(&hw_breakpoint_test_suite);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Marco Elver <elver@google.com>");
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
new file mode 100644
index 000000000..5150d5f84
--- /dev/null
+++ b/kernel/events/internal.h
@@ -0,0 +1,246 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _KERNEL_EVENTS_INTERNAL_H
+#define _KERNEL_EVENTS_INTERNAL_H
+
+#include <linux/hardirq.h>
+#include <linux/uaccess.h>
+#include <linux/refcount.h>
+
+/* Buffer handling */
+
+#define RING_BUFFER_WRITABLE		0x01
+
+struct perf_buffer {
+	refcount_t			refcount;
+	struct rcu_head			rcu_head;
+#ifdef CONFIG_PERF_USE_VMALLOC
+	struct work_struct		work;
+	int				page_order;	/* allocation order  */
+#endif
+	int				nr_pages;	/* nr of data pages  */
+	int				overwrite;	/* can overwrite itself */
+	int				paused;		/* can write into ring buffer */
+
+	atomic_t			poll;		/* POLL_ for wakeups */
+
+	local_t				head;		/* write position    */
+	unsigned int			nest;		/* nested writers    */
+	local_t				events;		/* event limit       */
+	local_t				wakeup;		/* wakeup stamp      */
+	local_t				lost;		/* nr records lost   */
+
+	long				watermark;	/* wakeup watermark  */
+	long				aux_watermark;
+	/* poll crap */
+	spinlock_t			event_lock;
+	struct list_head		event_list;
+
+	atomic_t			mmap_count;
+	unsigned long			mmap_locked;
+	struct user_struct		*mmap_user;
+
+	/* AUX area */
+	long				aux_head;
+	unsigned int			aux_nest;
+	long				aux_wakeup;	/* last aux_watermark boundary crossed by aux_head */
+	unsigned long			aux_pgoff;
+	int				aux_nr_pages;
+	int				aux_overwrite;
+	atomic_t			aux_mmap_count;
+	unsigned long			aux_mmap_locked;
+	void				(*free_aux)(void *);
+	refcount_t			aux_refcount;
+	int				aux_in_sampling;
+	void				**aux_pages;
+	void				*aux_priv;
+
+	struct perf_event_mmap_page	*user_page;
+	void				*data_pages[];
+};
+
+extern void rb_free(struct perf_buffer *rb);
+
+static inline void rb_free_rcu(struct rcu_head *rcu_head)
+{
+	struct perf_buffer *rb;
+
+	rb = container_of(rcu_head, struct perf_buffer, rcu_head);
+	rb_free(rb);
+}
+
+static inline void rb_toggle_paused(struct perf_buffer *rb, bool pause)
+{
+	if (!pause && rb->nr_pages)
+		rb->paused = 0;
+	else
+		rb->paused = 1;
+}
+
+extern struct perf_buffer *
+rb_alloc(int nr_pages, long watermark, int cpu, int flags);
+extern void perf_event_wakeup(struct perf_event *event);
+extern int rb_alloc_aux(struct perf_buffer *rb, struct perf_event *event,
+			pgoff_t pgoff, int nr_pages, long watermark, int flags);
+extern void rb_free_aux(struct perf_buffer *rb);
+extern struct perf_buffer *ring_buffer_get(struct perf_event *event);
+extern void ring_buffer_put(struct perf_buffer *rb);
+
+static inline bool rb_has_aux(struct perf_buffer *rb)
+{
+	return !!rb->aux_nr_pages;
+}
+
+void perf_event_aux_event(struct perf_event *event, unsigned long head,
+			  unsigned long size, u64 flags);
+
+extern struct page *
+perf_mmap_to_page(struct perf_buffer *rb, unsigned long pgoff);
+
+#ifdef CONFIG_PERF_USE_VMALLOC
+/*
+ * Back perf_mmap() with vmalloc memory.
+ *
+ * Required for architectures that have d-cache aliasing issues.
+ */
+
+static inline int page_order(struct perf_buffer *rb)
+{
+	return rb->page_order;
+}
+
+#else
+
+static inline int page_order(struct perf_buffer *rb)
+{
+	return 0;
+}
+#endif
+
+static inline int data_page_nr(struct perf_buffer *rb)
+{
+	return rb->nr_pages << page_order(rb);
+}
+
+static inline unsigned long perf_data_size(struct perf_buffer *rb)
+{
+	return rb->nr_pages << (PAGE_SHIFT + page_order(rb));
+}
+
+static inline unsigned long perf_aux_size(struct perf_buffer *rb)
+{
+	return rb->aux_nr_pages << PAGE_SHIFT;
+}
+
+#define __DEFINE_OUTPUT_COPY_BODY(advance_buf, memcpy_func, ...)	\
+{									\
+	unsigned long size, written;					\
+									\
+	do {								\
+		size    = min(handle->size, len);			\
+		written = memcpy_func(__VA_ARGS__);			\
+		written = size - written;				\
+									\
+		len -= written;						\
+		handle->addr += written;				\
+		if (advance_buf)					\
+			buf += written;					\
+		handle->size -= written;				\
+		if (!handle->size) {					\
+			struct perf_buffer *rb = handle->rb;	\
+									\
+			handle->page++;					\
+			handle->page &= rb->nr_pages - 1;		\
+			handle->addr = rb->data_pages[handle->page];	\
+			handle->size = PAGE_SIZE << page_order(rb);	\
+		}							\
+	} while (len && written == size);				\
+									\
+	return len;							\
+}
+
+#define DEFINE_OUTPUT_COPY(func_name, memcpy_func)			\
+static inline unsigned long						\
+func_name(struct perf_output_handle *handle,				\
+	  const void *buf, unsigned long len)				\
+__DEFINE_OUTPUT_COPY_BODY(true, memcpy_func, handle->addr, buf, size)
+
+static inline unsigned long
+__output_custom(struct perf_output_handle *handle, perf_copy_f copy_func,
+		const void *buf, unsigned long len)
+{
+	unsigned long orig_len = len;
+	__DEFINE_OUTPUT_COPY_BODY(false, copy_func, handle->addr, buf,
+				  orig_len - len, size)
+}
+
+static inline unsigned long
+memcpy_common(void *dst, const void *src, unsigned long n)
+{
+	memcpy(dst, src, n);
+	return 0;
+}
+
+DEFINE_OUTPUT_COPY(__output_copy, memcpy_common)
+
+static inline unsigned long
+memcpy_skip(void *dst, const void *src, unsigned long n)
+{
+	return 0;
+}
+
+DEFINE_OUTPUT_COPY(__output_skip, memcpy_skip)
+
+#ifndef arch_perf_out_copy_user
+#define arch_perf_out_copy_user arch_perf_out_copy_user
+
+static inline unsigned long
+arch_perf_out_copy_user(void *dst, const void *src, unsigned long n)
+{
+	unsigned long ret;
+
+	pagefault_disable();
+	ret = __copy_from_user_inatomic(dst, src, n);
+	pagefault_enable();
+
+	return ret;
+}
+#endif
+
+DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user)
+
+static inline int get_recursion_context(int *recursion)
+{
+	unsigned char rctx = interrupt_context_level();
+
+	if (recursion[rctx])
+		return -1;
+
+	recursion[rctx]++;
+	barrier();
+
+	return rctx;
+}
+
+static inline void put_recursion_context(int *recursion, int rctx)
+{
+	barrier();
+	recursion[rctx]--;
+}
+
+#ifdef CONFIG_HAVE_PERF_USER_STACK_DUMP
+static inline bool arch_perf_have_user_stack_dump(void)
+{
+	return true;
+}
+
+#define perf_user_stack_pointer(regs) user_stack_pointer(regs)
+#else
+static inline bool arch_perf_have_user_stack_dump(void)
+{
+	return false;
+}
+
+#define perf_user_stack_pointer(regs) 0
+#endif /* CONFIG_HAVE_PERF_USER_STACK_DUMP */
+
+#endif /* _KERNEL_EVENTS_INTERNAL_H */
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
new file mode 100644
index 000000000..45965f137
--- /dev/null
+++ b/kernel/events/ring_buffer.c
@@ -0,0 +1,968 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Performance events ring-buffer code:
+ *
+ *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
+ *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
+ *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
+ *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
+ */
+
+#include <linux/perf_event.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+#include <linux/circ_buf.h>
+#include <linux/poll.h>
+#include <linux/nospec.h>
+
+#include "internal.h"
+
+static void perf_output_wakeup(struct perf_output_handle *handle)
+{
+	atomic_set(&handle->rb->poll, EPOLLIN);
+
+	handle->event->pending_wakeup = 1;
+	irq_work_queue(&handle->event->pending_irq);
+}
+
+/*
+ * We need to ensure a later event_id doesn't publish a head when a former
+ * event isn't done writing. However since we need to deal with NMIs we
+ * cannot fully serialize things.
+ *
+ * We only publish the head (and generate a wakeup) when the outer-most
+ * event completes.
+ */
+static void perf_output_get_handle(struct perf_output_handle *handle)
+{
+	struct perf_buffer *rb = handle->rb;
+
+	preempt_disable();
+
+	/*
+	 * Avoid an explicit LOAD/STORE such that architectures with memops
+	 * can use them.
+	 */
+	(*(volatile unsigned int *)&rb->nest)++;
+	handle->wakeup = local_read(&rb->wakeup);
+}
+
+static void perf_output_put_handle(struct perf_output_handle *handle)
+{
+	struct perf_buffer *rb = handle->rb;
+	unsigned long head;
+	unsigned int nest;
+
+	/*
+	 * If this isn't the outermost nesting, we don't have to update
+	 * @rb->user_page->data_head.
+	 */
+	nest = READ_ONCE(rb->nest);
+	if (nest > 1) {
+		WRITE_ONCE(rb->nest, nest - 1);
+		goto out;
+	}
+
+again:
+	/*
+	 * In order to avoid publishing a head value that goes backwards,
+	 * we must ensure the load of @rb->head happens after we've
+	 * incremented @rb->nest.
+	 *
+	 * Otherwise we can observe a @rb->head value before one published
+	 * by an IRQ/NMI happening between the load and the increment.
+	 */
+	barrier();
+	head = local_read(&rb->head);
+
+	/*
+	 * IRQ/NMI can happen here and advance @rb->head, causing our
+	 * load above to be stale.
+	 */
+
+	/*
+	 * Since the mmap() consumer (userspace) can run on a different CPU:
+	 *
+	 *   kernel				user
+	 *
+	 *   if (LOAD ->data_tail) {		LOAD ->data_head
+	 *			(A)		smp_rmb()	(C)
+	 *	STORE $data			LOAD $data
+	 *	smp_wmb()	(B)		smp_mb()	(D)
+	 *	STORE ->data_head		STORE ->data_tail
+	 *   }
+	 *
+	 * Where A pairs with D, and B pairs with C.
+	 *
+	 * In our case (A) is a control dependency that separates the load of
+	 * the ->data_tail and the stores of $data. In case ->data_tail
+	 * indicates there is no room in the buffer to store $data we do not.
+	 *
+	 * D needs to be a full barrier since it separates the data READ
+	 * from the tail WRITE.
+	 *
+	 * For B a WMB is sufficient since it separates two WRITEs, and for C
+	 * an RMB is sufficient since it separates two READs.
+	 *
+	 * See perf_output_begin().
+	 */
+	smp_wmb(); /* B, matches C */
+	WRITE_ONCE(rb->user_page->data_head, head);
+
+	/*
+	 * We must publish the head before decrementing the nest count,
+	 * otherwise an IRQ/NMI can publish a more recent head value and our
+	 * write will (temporarily) publish a stale value.
+	 */
+	barrier();
+	WRITE_ONCE(rb->nest, 0);
+
+	/*
+	 * Ensure we decrement @rb->nest before we validate the @rb->head.
+	 * Otherwise we cannot be sure we caught the 'last' nested update.
+	 */
+	barrier();
+	if (unlikely(head != local_read(&rb->head))) {
+		WRITE_ONCE(rb->nest, 1);
+		goto again;
+	}
+
+	if (handle->wakeup != local_read(&rb->wakeup))
+		perf_output_wakeup(handle);
+
+out:
+	preempt_enable();
+}
+
+static __always_inline bool
+ring_buffer_has_space(unsigned long head, unsigned long tail,
+		      unsigned long data_size, unsigned int size,
+		      bool backward)
+{
+	if (!backward)
+		return CIRC_SPACE(head, tail, data_size) >= size;
+	else
+		return CIRC_SPACE(tail, head, data_size) >= size;
+}
+
+static __always_inline int
+__perf_output_begin(struct perf_output_handle *handle,
+		    struct perf_sample_data *data,
+		    struct perf_event *event, unsigned int size,
+		    bool backward)
+{
+	struct perf_buffer *rb;
+	unsigned long tail, offset, head;
+	int have_lost, page_shift;
+	struct {
+		struct perf_event_header header;
+		u64			 id;
+		u64			 lost;
+	} lost_event;
+
+	rcu_read_lock();
+	/*
+	 * For inherited events we send all the output towards the parent.
+	 */
+	if (event->parent)
+		event = event->parent;
+
+	rb = rcu_dereference(event->rb);
+	if (unlikely(!rb))
+		goto out;
+
+	if (unlikely(rb->paused)) {
+		if (rb->nr_pages) {
+			local_inc(&rb->lost);
+			atomic64_inc(&event->lost_samples);
+		}
+		goto out;
+	}
+
+	handle->rb    = rb;
+	handle->event = event;
+
+	have_lost = local_read(&rb->lost);
+	if (unlikely(have_lost)) {
+		size += sizeof(lost_event);
+		if (event->attr.sample_id_all)
+			size += event->id_header_size;
+	}
+
+	perf_output_get_handle(handle);
+
+	do {
+		tail = READ_ONCE(rb->user_page->data_tail);
+		offset = head = local_read(&rb->head);
+		if (!rb->overwrite) {
+			if (unlikely(!ring_buffer_has_space(head, tail,
+							    perf_data_size(rb),
+							    size, backward)))
+				goto fail;
+		}
+
+		/*
+		 * The above forms a control dependency barrier separating the
+		 * @tail load above from the data stores below. Since the @tail
+		 * load is required to compute the branch to fail below.
+		 *
+		 * A, matches D; the full memory barrier userspace SHOULD issue
+		 * after reading the data and before storing the new tail
+		 * position.
+		 *
+		 * See perf_output_put_handle().
+		 */
+
+		if (!backward)
+			head += size;
+		else
+			head -= size;
+	} while (local_cmpxchg(&rb->head, offset, head) != offset);
+
+	if (backward) {
+		offset = head;
+		head = (u64)(-head);
+	}
+
+	/*
+	 * We rely on the implied barrier() by local_cmpxchg() to ensure
+	 * none of the data stores below can be lifted up by the compiler.
+	 */
+
+	if (unlikely(head - local_read(&rb->wakeup) > rb->watermark))
+		local_add(rb->watermark, &rb->wakeup);
+
+	page_shift = PAGE_SHIFT + page_order(rb);
+
+	handle->page = (offset >> page_shift) & (rb->nr_pages - 1);
+	offset &= (1UL << page_shift) - 1;
+	handle->addr = rb->data_pages[handle->page] + offset;
+	handle->size = (1UL << page_shift) - offset;
+
+	if (unlikely(have_lost)) {
+		lost_event.header.size = sizeof(lost_event);
+		lost_event.header.type = PERF_RECORD_LOST;
+		lost_event.header.misc = 0;
+		lost_event.id          = event->id;
+		lost_event.lost        = local_xchg(&rb->lost, 0);
+
+		/* XXX mostly redundant; @data is already fully initializes */
+		perf_event_header__init_id(&lost_event.header, data, event);
+		perf_output_put(handle, lost_event);
+		perf_event__output_id_sample(event, handle, data);
+	}
+
+	return 0;
+
+fail:
+	local_inc(&rb->lost);
+	atomic64_inc(&event->lost_samples);
+	perf_output_put_handle(handle);
+out:
+	rcu_read_unlock();
+
+	return -ENOSPC;
+}
+
+int perf_output_begin_forward(struct perf_output_handle *handle,
+			      struct perf_sample_data *data,
+			      struct perf_event *event, unsigned int size)
+{
+	return __perf_output_begin(handle, data, event, size, false);
+}
+
+int perf_output_begin_backward(struct perf_output_handle *handle,
+			       struct perf_sample_data *data,
+			       struct perf_event *event, unsigned int size)
+{
+	return __perf_output_begin(handle, data, event, size, true);
+}
+
+int perf_output_begin(struct perf_output_handle *handle,
+		      struct perf_sample_data *data,
+		      struct perf_event *event, unsigned int size)
+{
+
+	return __perf_output_begin(handle, data, event, size,
+				   unlikely(is_write_backward(event)));
+}
+
+unsigned int perf_output_copy(struct perf_output_handle *handle,
+		      const void *buf, unsigned int len)
+{
+	return __output_copy(handle, buf, len);
+}
+
+unsigned int perf_output_skip(struct perf_output_handle *handle,
+			      unsigned int len)
+{
+	return __output_skip(handle, NULL, len);
+}
+
+void perf_output_end(struct perf_output_handle *handle)
+{
+	perf_output_put_handle(handle);
+	rcu_read_unlock();
+}
+
+static void
+ring_buffer_init(struct perf_buffer *rb, long watermark, int flags)
+{
+	long max_size = perf_data_size(rb);
+
+	if (watermark)
+		rb->watermark = min(max_size, watermark);
+
+	if (!rb->watermark)
+		rb->watermark = max_size / 2;
+
+	if (flags & RING_BUFFER_WRITABLE)
+		rb->overwrite = 0;
+	else
+		rb->overwrite = 1;
+
+	refcount_set(&rb->refcount, 1);
+
+	INIT_LIST_HEAD(&rb->event_list);
+	spin_lock_init(&rb->event_lock);
+
+	/*
+	 * perf_output_begin() only checks rb->paused, therefore
+	 * rb->paused must be true if we have no pages for output.
+	 */
+	if (!rb->nr_pages)
+		rb->paused = 1;
+}
+
+void perf_aux_output_flag(struct perf_output_handle *handle, u64 flags)
+{
+	/*
+	 * OVERWRITE is determined by perf_aux_output_end() and can't
+	 * be passed in directly.
+	 */
+	if (WARN_ON_ONCE(flags & PERF_AUX_FLAG_OVERWRITE))
+		return;
+
+	handle->aux_flags |= flags;
+}
+EXPORT_SYMBOL_GPL(perf_aux_output_flag);
+
+/*
+ * This is called before hardware starts writing to the AUX area to
+ * obtain an output handle and make sure there's room in the buffer.
+ * When the capture completes, call perf_aux_output_end() to commit
+ * the recorded data to the buffer.
+ *
+ * The ordering is similar to that of perf_output_{begin,end}, with
+ * the exception of (B), which should be taken care of by the pmu
+ * driver, since ordering rules will differ depending on hardware.
+ *
+ * Call this from pmu::start(); see the comment in perf_aux_output_end()
+ * about its use in pmu callbacks. Both can also be called from the PMI
+ * handler if needed.
+ */
+void *perf_aux_output_begin(struct perf_output_handle *handle,
+			    struct perf_event *event)
+{
+	struct perf_event *output_event = event;
+	unsigned long aux_head, aux_tail;
+	struct perf_buffer *rb;
+	unsigned int nest;
+
+	if (output_event->parent)
+		output_event = output_event->parent;
+
+	/*
+	 * Since this will typically be open across pmu::add/pmu::del, we
+	 * grab ring_buffer's refcount instead of holding rcu read lock
+	 * to make sure it doesn't disappear under us.
+	 */
+	rb = ring_buffer_get(output_event);
+	if (!rb)
+		return NULL;
+
+	if (!rb_has_aux(rb))
+		goto err;
+
+	/*
+	 * If aux_mmap_count is zero, the aux buffer is in perf_mmap_close(),
+	 * about to get freed, so we leave immediately.
+	 *
+	 * Checking rb::aux_mmap_count and rb::refcount has to be done in
+	 * the same order, see perf_mmap_close. Otherwise we end up freeing
+	 * aux pages in this path, which is a bug, because in_atomic().
+	 */
+	if (!atomic_read(&rb->aux_mmap_count))
+		goto err;
+
+	if (!refcount_inc_not_zero(&rb->aux_refcount))
+		goto err;
+
+	nest = READ_ONCE(rb->aux_nest);
+	/*
+	 * Nesting is not supported for AUX area, make sure nested
+	 * writers are caught early
+	 */
+	if (WARN_ON_ONCE(nest))
+		goto err_put;
+
+	WRITE_ONCE(rb->aux_nest, nest + 1);
+
+	aux_head = rb->aux_head;
+
+	handle->rb = rb;
+	handle->event = event;
+	handle->head = aux_head;
+	handle->size = 0;
+	handle->aux_flags = 0;
+
+	/*
+	 * In overwrite mode, AUX data stores do not depend on aux_tail,
+	 * therefore (A) control dependency barrier does not exist. The
+	 * (B) <-> (C) ordering is still observed by the pmu driver.
+	 */
+	if (!rb->aux_overwrite) {
+		aux_tail = READ_ONCE(rb->user_page->aux_tail);
+		handle->wakeup = rb->aux_wakeup + rb->aux_watermark;
+		if (aux_head - aux_tail < perf_aux_size(rb))
+			handle->size = CIRC_SPACE(aux_head, aux_tail, perf_aux_size(rb));
+
+		/*
+		 * handle->size computation depends on aux_tail load; this forms a
+		 * control dependency barrier separating aux_tail load from aux data
+		 * store that will be enabled on successful return
+		 */
+		if (!handle->size) { /* A, matches D */
+			event->pending_disable = smp_processor_id();
+			perf_output_wakeup(handle);
+			WRITE_ONCE(rb->aux_nest, 0);
+			goto err_put;
+		}
+	}
+
+	return handle->rb->aux_priv;
+
+err_put:
+	/* can't be last */
+	rb_free_aux(rb);
+
+err:
+	ring_buffer_put(rb);
+	handle->event = NULL;
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(perf_aux_output_begin);
+
+static __always_inline bool rb_need_aux_wakeup(struct perf_buffer *rb)
+{
+	if (rb->aux_overwrite)
+		return false;
+
+	if (rb->aux_head - rb->aux_wakeup >= rb->aux_watermark) {
+		rb->aux_wakeup = rounddown(rb->aux_head, rb->aux_watermark);
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * Commit the data written by hardware into the ring buffer by adjusting
+ * aux_head and posting a PERF_RECORD_AUX into the perf buffer. It is the
+ * pmu driver's responsibility to observe ordering rules of the hardware,
+ * so that all the data is externally visible before this is called.
+ *
+ * Note: this has to be called from pmu::stop() callback, as the assumption
+ * of the AUX buffer management code is that after pmu::stop(), the AUX
+ * transaction must be stopped and therefore drop the AUX reference count.
+ */
+void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size)
+{
+	bool wakeup = !!(handle->aux_flags & PERF_AUX_FLAG_TRUNCATED);
+	struct perf_buffer *rb = handle->rb;
+	unsigned long aux_head;
+
+	/* in overwrite mode, driver provides aux_head via handle */
+	if (rb->aux_overwrite) {
+		handle->aux_flags |= PERF_AUX_FLAG_OVERWRITE;
+
+		aux_head = handle->head;
+		rb->aux_head = aux_head;
+	} else {
+		handle->aux_flags &= ~PERF_AUX_FLAG_OVERWRITE;
+
+		aux_head = rb->aux_head;
+		rb->aux_head += size;
+	}
+
+	/*
+	 * Only send RECORD_AUX if we have something useful to communicate
+	 *
+	 * Note: the OVERWRITE records by themselves are not considered
+	 * useful, as they don't communicate any *new* information,
+	 * aside from the short-lived offset, that becomes history at
+	 * the next event sched-in and therefore isn't useful.
+	 * The userspace that needs to copy out AUX data in overwrite
+	 * mode should know to use user_page::aux_head for the actual
+	 * offset. So, from now on we don't output AUX records that
+	 * have *only* OVERWRITE flag set.
+	 */
+	if (size || (handle->aux_flags & ~(u64)PERF_AUX_FLAG_OVERWRITE))
+		perf_event_aux_event(handle->event, aux_head, size,
+				     handle->aux_flags);
+
+	WRITE_ONCE(rb->user_page->aux_head, rb->aux_head);
+	if (rb_need_aux_wakeup(rb))
+		wakeup = true;
+
+	if (wakeup) {
+		if (handle->aux_flags & PERF_AUX_FLAG_TRUNCATED)
+			handle->event->pending_disable = smp_processor_id();
+		perf_output_wakeup(handle);
+	}
+
+	handle->event = NULL;
+
+	WRITE_ONCE(rb->aux_nest, 0);
+	/* can't be last */
+	rb_free_aux(rb);
+	ring_buffer_put(rb);
+}
+EXPORT_SYMBOL_GPL(perf_aux_output_end);
+
+/*
+ * Skip over a given number of bytes in the AUX buffer, due to, for example,
+ * hardware's alignment constraints.
+ */
+int perf_aux_output_skip(struct perf_output_handle *handle, unsigned long size)
+{
+	struct perf_buffer *rb = handle->rb;
+
+	if (size > handle->size)
+		return -ENOSPC;
+
+	rb->aux_head += size;
+
+	WRITE_ONCE(rb->user_page->aux_head, rb->aux_head);
+	if (rb_need_aux_wakeup(rb)) {
+		perf_output_wakeup(handle);
+		handle->wakeup = rb->aux_wakeup + rb->aux_watermark;
+	}
+
+	handle->head = rb->aux_head;
+	handle->size -= size;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(perf_aux_output_skip);
+
+void *perf_get_aux(struct perf_output_handle *handle)
+{
+	/* this is only valid between perf_aux_output_begin and *_end */
+	if (!handle->event)
+		return NULL;
+
+	return handle->rb->aux_priv;
+}
+EXPORT_SYMBOL_GPL(perf_get_aux);
+
+/*
+ * Copy out AUX data from an AUX handle.
+ */
+long perf_output_copy_aux(struct perf_output_handle *aux_handle,
+			  struct perf_output_handle *handle,
+			  unsigned long from, unsigned long to)
+{
+	struct perf_buffer *rb = aux_handle->rb;
+	unsigned long tocopy, remainder, len = 0;
+	void *addr;
+
+	from &= (rb->aux_nr_pages << PAGE_SHIFT) - 1;
+	to &= (rb->aux_nr_pages << PAGE_SHIFT) - 1;
+
+	do {
+		tocopy = PAGE_SIZE - offset_in_page(from);
+		if (to > from)
+			tocopy = min(tocopy, to - from);
+		if (!tocopy)
+			break;
+
+		addr = rb->aux_pages[from >> PAGE_SHIFT];
+		addr += offset_in_page(from);
+
+		remainder = perf_output_copy(handle, addr, tocopy);
+		if (remainder)
+			return -EFAULT;
+
+		len += tocopy;
+		from += tocopy;
+		from &= (rb->aux_nr_pages << PAGE_SHIFT) - 1;
+	} while (to != from);
+
+	return len;
+}
+
+#define PERF_AUX_GFP	(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_NORETRY)
+
+static struct page *rb_alloc_aux_page(int node, int order)
+{
+	struct page *page;
+
+	if (order > MAX_ORDER)
+		order = MAX_ORDER;
+
+	do {
+		page = alloc_pages_node(node, PERF_AUX_GFP, order);
+	} while (!page && order--);
+
+	if (page && order) {
+		/*
+		 * Communicate the allocation size to the driver:
+		 * if we managed to secure a high-order allocation,
+		 * set its first page's private to this order;
+		 * !PagePrivate(page) means it's just a normal page.
+		 */
+		split_page(page, order);
+		SetPagePrivate(page);
+		set_page_private(page, order);
+	}
+
+	return page;
+}
+
+static void rb_free_aux_page(struct perf_buffer *rb, int idx)
+{
+	struct page *page = virt_to_page(rb->aux_pages[idx]);
+
+	ClearPagePrivate(page);
+	page->mapping = NULL;
+	__free_page(page);
+}
+
+static void __rb_free_aux(struct perf_buffer *rb)
+{
+	int pg;
+
+	/*
+	 * Should never happen, the last reference should be dropped from
+	 * perf_mmap_close() path, which first stops aux transactions (which
+	 * in turn are the atomic holders of aux_refcount) and then does the
+	 * last rb_free_aux().
+	 */
+	WARN_ON_ONCE(in_atomic());
+
+	if (rb->aux_priv) {
+		rb->free_aux(rb->aux_priv);
+		rb->free_aux = NULL;
+		rb->aux_priv = NULL;
+	}
+
+	if (rb->aux_nr_pages) {
+		for (pg = 0; pg < rb->aux_nr_pages; pg++)
+			rb_free_aux_page(rb, pg);
+
+		kfree(rb->aux_pages);
+		rb->aux_nr_pages = 0;
+	}
+}
+
+int rb_alloc_aux(struct perf_buffer *rb, struct perf_event *event,
+		 pgoff_t pgoff, int nr_pages, long watermark, int flags)
+{
+	bool overwrite = !(flags & RING_BUFFER_WRITABLE);
+	int node = (event->cpu == -1) ? -1 : cpu_to_node(event->cpu);
+	int ret = -ENOMEM, max_order;
+
+	if (!has_aux(event))
+		return -EOPNOTSUPP;
+
+	if (!overwrite) {
+		/*
+		 * Watermark defaults to half the buffer, and so does the
+		 * max_order, to aid PMU drivers in double buffering.
+		 */
+		if (!watermark)
+			watermark = nr_pages << (PAGE_SHIFT - 1);
+
+		/*
+		 * Use aux_watermark as the basis for chunking to
+		 * help PMU drivers honor the watermark.
+		 */
+		max_order = get_order(watermark);
+	} else {
+		/*
+		 * We need to start with the max_order that fits in nr_pages,
+		 * not the other way around, hence ilog2() and not get_order.
+		 */
+		max_order = ilog2(nr_pages);
+		watermark = 0;
+	}
+
+	/*
+	 * kcalloc_node() is unable to allocate buffer if the size is larger
+	 * than: PAGE_SIZE << MAX_ORDER; directly bail out in this case.
+	 */
+	if (get_order((unsigned long)nr_pages * sizeof(void *)) > MAX_ORDER)
+		return -ENOMEM;
+	rb->aux_pages = kcalloc_node(nr_pages, sizeof(void *), GFP_KERNEL,
+				     node);
+	if (!rb->aux_pages)
+		return -ENOMEM;
+
+	rb->free_aux = event->pmu->free_aux;
+	for (rb->aux_nr_pages = 0; rb->aux_nr_pages < nr_pages;) {
+		struct page *page;
+		int last, order;
+
+		order = min(max_order, ilog2(nr_pages - rb->aux_nr_pages));
+		page = rb_alloc_aux_page(node, order);
+		if (!page)
+			goto out;
+
+		for (last = rb->aux_nr_pages + (1 << page_private(page));
+		     last > rb->aux_nr_pages; rb->aux_nr_pages++)
+			rb->aux_pages[rb->aux_nr_pages] = page_address(page++);
+	}
+
+	/*
+	 * In overwrite mode, PMUs that don't support SG may not handle more
+	 * than one contiguous allocation, since they rely on PMI to do double
+	 * buffering. In this case, the entire buffer has to be one contiguous
+	 * chunk.
+	 */
+	if ((event->pmu->capabilities & PERF_PMU_CAP_AUX_NO_SG) &&
+	    overwrite) {
+		struct page *page = virt_to_page(rb->aux_pages[0]);
+
+		if (page_private(page) != max_order)
+			goto out;
+	}
+
+	rb->aux_priv = event->pmu->setup_aux(event, rb->aux_pages, nr_pages,
+					     overwrite);
+	if (!rb->aux_priv)
+		goto out;
+
+	ret = 0;
+
+	/*
+	 * aux_pages (and pmu driver's private data, aux_priv) will be
+	 * referenced in both producer's and consumer's contexts, thus
+	 * we keep a refcount here to make sure either of the two can
+	 * reference them safely.
+	 */
+	refcount_set(&rb->aux_refcount, 1);
+
+	rb->aux_overwrite = overwrite;
+	rb->aux_watermark = watermark;
+
+out:
+	if (!ret)
+		rb->aux_pgoff = pgoff;
+	else
+		__rb_free_aux(rb);
+
+	return ret;
+}
+
+void rb_free_aux(struct perf_buffer *rb)
+{
+	if (refcount_dec_and_test(&rb->aux_refcount))
+		__rb_free_aux(rb);
+}
+
+#ifndef CONFIG_PERF_USE_VMALLOC
+
+/*
+ * Back perf_mmap() with regular GFP_KERNEL-0 pages.
+ */
+
+static struct page *
+__perf_mmap_to_page(struct perf_buffer *rb, unsigned long pgoff)
+{
+	if (pgoff > rb->nr_pages)
+		return NULL;
+
+	if (pgoff == 0)
+		return virt_to_page(rb->user_page);
+
+	return virt_to_page(rb->data_pages[pgoff - 1]);
+}
+
+static void *perf_mmap_alloc_page(int cpu)
+{
+	struct page *page;
+	int node;
+
+	node = (cpu == -1) ? cpu : cpu_to_node(cpu);
+	page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
+	if (!page)
+		return NULL;
+
+	return page_address(page);
+}
+
+static void perf_mmap_free_page(void *addr)
+{
+	struct page *page = virt_to_page(addr);
+
+	page->mapping = NULL;
+	__free_page(page);
+}
+
+struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
+{
+	struct perf_buffer *rb;
+	unsigned long size;
+	int i, node;
+
+	size = sizeof(struct perf_buffer);
+	size += nr_pages * sizeof(void *);
+
+	if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
+		goto fail;
+
+	node = (cpu == -1) ? cpu : cpu_to_node(cpu);
+	rb = kzalloc_node(size, GFP_KERNEL, node);
+	if (!rb)
+		goto fail;
+
+	rb->user_page = perf_mmap_alloc_page(cpu);
+	if (!rb->user_page)
+		goto fail_user_page;
+
+	for (i = 0; i < nr_pages; i++) {
+		rb->data_pages[i] = perf_mmap_alloc_page(cpu);
+		if (!rb->data_pages[i])
+			goto fail_data_pages;
+	}
+
+	rb->nr_pages = nr_pages;
+
+	ring_buffer_init(rb, watermark, flags);
+
+	return rb;
+
+fail_data_pages:
+	for (i--; i >= 0; i--)
+		perf_mmap_free_page(rb->data_pages[i]);
+
+	perf_mmap_free_page(rb->user_page);
+
+fail_user_page:
+	kfree(rb);
+
+fail:
+	return NULL;
+}
+
+void rb_free(struct perf_buffer *rb)
+{
+	int i;
+
+	perf_mmap_free_page(rb->user_page);
+	for (i = 0; i < rb->nr_pages; i++)
+		perf_mmap_free_page(rb->data_pages[i]);
+	kfree(rb);
+}
+
+#else
+static struct page *
+__perf_mmap_to_page(struct perf_buffer *rb, unsigned long pgoff)
+{
+	/* The '>' counts in the user page. */
+	if (pgoff > data_page_nr(rb))
+		return NULL;
+
+	return vmalloc_to_page((void *)rb->user_page + pgoff * PAGE_SIZE);
+}
+
+static void perf_mmap_unmark_page(void *addr)
+{
+	struct page *page = vmalloc_to_page(addr);
+
+	page->mapping = NULL;
+}
+
+static void rb_free_work(struct work_struct *work)
+{
+	struct perf_buffer *rb;
+	void *base;
+	int i, nr;
+
+	rb = container_of(work, struct perf_buffer, work);
+	nr = data_page_nr(rb);
+
+	base = rb->user_page;
+	/* The '<=' counts in the user page. */
+	for (i = 0; i <= nr; i++)
+		perf_mmap_unmark_page(base + (i * PAGE_SIZE));
+
+	vfree(base);
+	kfree(rb);
+}
+
+void rb_free(struct perf_buffer *rb)
+{
+	schedule_work(&rb->work);
+}
+
+struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
+{
+	struct perf_buffer *rb;
+	unsigned long size;
+	void *all_buf;
+	int node;
+
+	size = sizeof(struct perf_buffer);
+	size += sizeof(void *);
+
+	node = (cpu == -1) ? cpu : cpu_to_node(cpu);
+	rb = kzalloc_node(size, GFP_KERNEL, node);
+	if (!rb)
+		goto fail;
+
+	INIT_WORK(&rb->work, rb_free_work);
+
+	all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
+	if (!all_buf)
+		goto fail_all_buf;
+
+	rb->user_page = all_buf;
+	rb->data_pages[0] = all_buf + PAGE_SIZE;
+	if (nr_pages) {
+		rb->nr_pages = 1;
+		rb->page_order = ilog2(nr_pages);
+	}
+
+	ring_buffer_init(rb, watermark, flags);
+
+	return rb;
+
+fail_all_buf:
+	kfree(rb);
+
+fail:
+	return NULL;
+}
+
+#endif
+
+struct page *
+perf_mmap_to_page(struct perf_buffer *rb, unsigned long pgoff)
+{
+	if (rb->aux_nr_pages) {
+		/* above AUX space */
+		if (pgoff > rb->aux_pgoff + rb->aux_nr_pages)
+			return NULL;
+
+		/* AUX space */
+		if (pgoff >= rb->aux_pgoff) {
+			int aux_pgoff = array_index_nospec(pgoff - rb->aux_pgoff, rb->aux_nr_pages);
+			return virt_to_page(rb->aux_pages[aux_pgoff]);
+		}
+	}
+
+	return __perf_mmap_to_page(rb, pgoff);
+}
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
new file mode 100644
index 000000000..d9e357b7e
--- /dev/null
+++ b/kernel/events/uprobes.c
@@ -0,0 +1,2359 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * User-space Probes (UProbes)
+ *
+ * Copyright (C) IBM Corporation, 2008-2012
+ * Authors:
+ *	Srikar Dronamraju
+ *	Jim Keniston
+ * Copyright (C) 2011-2012 Red Hat, Inc., Peter Zijlstra
+ */
+
+#include <linux/kernel.h>
+#include <linux/highmem.h>
+#include <linux/pagemap.h>	/* read_mapping_page */
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/coredump.h>
+#include <linux/export.h>
+#include <linux/rmap.h>		/* anon_vma_prepare */
+#include <linux/mmu_notifier.h>	/* set_pte_at_notify */
+#include <linux/swap.h>		/* folio_free_swap */
+#include <linux/ptrace.h>	/* user_enable_single_step */
+#include <linux/kdebug.h>	/* notifier mechanism */
+#include "../../mm/internal.h"	/* munlock_vma_page */
+#include <linux/percpu-rwsem.h>
+#include <linux/task_work.h>
+#include <linux/shmem_fs.h>
+#include <linux/khugepaged.h>
+
+#include <linux/uprobes.h>
+
+#define UINSNS_PER_PAGE			(PAGE_SIZE/UPROBE_XOL_SLOT_BYTES)
+#define MAX_UPROBE_XOL_SLOTS		UINSNS_PER_PAGE
+
+static struct rb_root uprobes_tree = RB_ROOT;
+/*
+ * allows us to skip the uprobe_mmap if there are no uprobe events active
+ * at this time.  Probably a fine grained per inode count is better?
+ */
+#define no_uprobe_events()	RB_EMPTY_ROOT(&uprobes_tree)
+
+static DEFINE_SPINLOCK(uprobes_treelock);	/* serialize rbtree access */
+
+#define UPROBES_HASH_SZ	13
+/* serialize uprobe->pending_list */
+static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
+#define uprobes_mmap_hash(v)	(&uprobes_mmap_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ])
+
+DEFINE_STATIC_PERCPU_RWSEM(dup_mmap_sem);
+
+/* Have a copy of original instruction */
+#define UPROBE_COPY_INSN	0
+
+struct uprobe {
+	struct rb_node		rb_node;	/* node in the rb tree */
+	refcount_t		ref;
+	struct rw_semaphore	register_rwsem;
+	struct rw_semaphore	consumer_rwsem;
+	struct list_head	pending_list;
+	struct uprobe_consumer	*consumers;
+	struct inode		*inode;		/* Also hold a ref to inode */
+	loff_t			offset;
+	loff_t			ref_ctr_offset;
+	unsigned long		flags;
+
+	/*
+	 * The generic code assumes that it has two members of unknown type
+	 * owned by the arch-specific code:
+	 *
+	 * 	insn -	copy_insn() saves the original instruction here for
+	 *		arch_uprobe_analyze_insn().
+	 *
+	 *	ixol -	potentially modified instruction to execute out of
+	 *		line, copied to xol_area by xol_get_insn_slot().
+	 */
+	struct arch_uprobe	arch;
+};
+
+struct delayed_uprobe {
+	struct list_head list;
+	struct uprobe *uprobe;
+	struct mm_struct *mm;
+};
+
+static DEFINE_MUTEX(delayed_uprobe_lock);
+static LIST_HEAD(delayed_uprobe_list);
+
+/*
+ * Execute out of line area: anonymous executable mapping installed
+ * by the probed task to execute the copy of the original instruction
+ * mangled by set_swbp().
+ *
+ * On a breakpoint hit, thread contests for a slot.  It frees the
+ * slot after singlestep. Currently a fixed number of slots are
+ * allocated.
+ */
+struct xol_area {
+	wait_queue_head_t 		wq;		/* if all slots are busy */
+	atomic_t 			slot_count;	/* number of in-use slots */
+	unsigned long 			*bitmap;	/* 0 = free slot */
+
+	struct vm_special_mapping	xol_mapping;
+	struct page 			*pages[2];
+	/*
+	 * We keep the vma's vm_start rather than a pointer to the vma
+	 * itself.  The probed process or a naughty kernel module could make
+	 * the vma go away, and we must handle that reasonably gracefully.
+	 */
+	unsigned long 			vaddr;		/* Page(s) of instruction slots */
+};
+
+/*
+ * valid_vma: Verify if the specified vma is an executable vma
+ * Relax restrictions while unregistering: vm_flags might have
+ * changed after breakpoint was inserted.
+ *	- is_register: indicates if we are in register context.
+ *	- Return 1 if the specified virtual address is in an
+ *	  executable vma.
+ */
+static bool valid_vma(struct vm_area_struct *vma, bool is_register)
+{
+	vm_flags_t flags = VM_HUGETLB | VM_MAYEXEC | VM_MAYSHARE;
+
+	if (is_register)
+		flags |= VM_WRITE;
+
+	return vma->vm_file && (vma->vm_flags & flags) == VM_MAYEXEC;
+}
+
+static unsigned long offset_to_vaddr(struct vm_area_struct *vma, loff_t offset)
+{
+	return vma->vm_start + offset - ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+}
+
+static loff_t vaddr_to_offset(struct vm_area_struct *vma, unsigned long vaddr)
+{
+	return ((loff_t)vma->vm_pgoff << PAGE_SHIFT) + (vaddr - vma->vm_start);
+}
+
+/**
+ * __replace_page - replace page in vma by new page.
+ * based on replace_page in mm/ksm.c
+ *
+ * @vma:      vma that holds the pte pointing to page
+ * @addr:     address the old @page is mapped at
+ * @old_page: the page we are replacing by new_page
+ * @new_page: the modified page we replace page by
+ *
+ * If @new_page is NULL, only unmap @old_page.
+ *
+ * Returns 0 on success, negative error code otherwise.
+ */
+static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
+				struct page *old_page, struct page *new_page)
+{
+	struct folio *old_folio = page_folio(old_page);
+	struct folio *new_folio;
+	struct mm_struct *mm = vma->vm_mm;
+	DEFINE_FOLIO_VMA_WALK(pvmw, old_folio, vma, addr, 0);
+	int err;
+	struct mmu_notifier_range range;
+
+	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, addr,
+				addr + PAGE_SIZE);
+
+	if (new_page) {
+		new_folio = page_folio(new_page);
+		err = mem_cgroup_charge(new_folio, vma->vm_mm, GFP_KERNEL);
+		if (err)
+			return err;
+	}
+
+	/* For folio_free_swap() below */
+	folio_lock(old_folio);
+
+	mmu_notifier_invalidate_range_start(&range);
+	err = -EAGAIN;
+	if (!page_vma_mapped_walk(&pvmw))
+		goto unlock;
+	VM_BUG_ON_PAGE(addr != pvmw.address, old_page);
+
+	if (new_page) {
+		folio_get(new_folio);
+		page_add_new_anon_rmap(new_page, vma, addr);
+		folio_add_lru_vma(new_folio, vma);
+	} else
+		/* no new page, just dec_mm_counter for old_page */
+		dec_mm_counter(mm, MM_ANONPAGES);
+
+	if (!folio_test_anon(old_folio)) {
+		dec_mm_counter(mm, mm_counter_file(old_page));
+		inc_mm_counter(mm, MM_ANONPAGES);
+	}
+
+	flush_cache_page(vma, addr, pte_pfn(*pvmw.pte));
+	ptep_clear_flush_notify(vma, addr, pvmw.pte);
+	if (new_page)
+		set_pte_at_notify(mm, addr, pvmw.pte,
+				  mk_pte(new_page, vma->vm_page_prot));
+
+	page_remove_rmap(old_page, vma, false);
+	if (!folio_mapped(old_folio))
+		folio_free_swap(old_folio);
+	page_vma_mapped_walk_done(&pvmw);
+	folio_put(old_folio);
+
+	err = 0;
+ unlock:
+	mmu_notifier_invalidate_range_end(&range);
+	folio_unlock(old_folio);
+	return err;
+}
+
+/**
+ * is_swbp_insn - check if instruction is breakpoint instruction.
+ * @insn: instruction to be checked.
+ * Default implementation of is_swbp_insn
+ * Returns true if @insn is a breakpoint instruction.
+ */
+bool __weak is_swbp_insn(uprobe_opcode_t *insn)
+{
+	return *insn == UPROBE_SWBP_INSN;
+}
+
+/**
+ * is_trap_insn - check if instruction is breakpoint instruction.
+ * @insn: instruction to be checked.
+ * Default implementation of is_trap_insn
+ * Returns true if @insn is a breakpoint instruction.
+ *
+ * This function is needed for the case where an architecture has multiple
+ * trap instructions (like powerpc).
+ */
+bool __weak is_trap_insn(uprobe_opcode_t *insn)
+{
+	return is_swbp_insn(insn);
+}
+
+static void copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len)
+{
+	void *kaddr = kmap_atomic(page);
+	memcpy(dst, kaddr + (vaddr & ~PAGE_MASK), len);
+	kunmap_atomic(kaddr);
+}
+
+static void copy_to_page(struct page *page, unsigned long vaddr, const void *src, int len)
+{
+	void *kaddr = kmap_atomic(page);
+	memcpy(kaddr + (vaddr & ~PAGE_MASK), src, len);
+	kunmap_atomic(kaddr);
+}
+
+static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)
+{
+	uprobe_opcode_t old_opcode;
+	bool is_swbp;
+
+	/*
+	 * Note: We only check if the old_opcode is UPROBE_SWBP_INSN here.
+	 * We do not check if it is any other 'trap variant' which could
+	 * be conditional trap instruction such as the one powerpc supports.
+	 *
+	 * The logic is that we do not care if the underlying instruction
+	 * is a trap variant; uprobes always wins over any other (gdb)
+	 * breakpoint.
+	 */
+	copy_from_page(page, vaddr, &old_opcode, UPROBE_SWBP_INSN_SIZE);
+	is_swbp = is_swbp_insn(&old_opcode);
+
+	if (is_swbp_insn(new_opcode)) {
+		if (is_swbp)		/* register: already installed? */
+			return 0;
+	} else {
+		if (!is_swbp)		/* unregister: was it changed by us? */
+			return 0;
+	}
+
+	return 1;
+}
+
+static struct delayed_uprobe *
+delayed_uprobe_check(struct uprobe *uprobe, struct mm_struct *mm)
+{
+	struct delayed_uprobe *du;
+
+	list_for_each_entry(du, &delayed_uprobe_list, list)
+		if (du->uprobe == uprobe && du->mm == mm)
+			return du;
+	return NULL;
+}
+
+static int delayed_uprobe_add(struct uprobe *uprobe, struct mm_struct *mm)
+{
+	struct delayed_uprobe *du;
+
+	if (delayed_uprobe_check(uprobe, mm))
+		return 0;
+
+	du  = kzalloc(sizeof(*du), GFP_KERNEL);
+	if (!du)
+		return -ENOMEM;
+
+	du->uprobe = uprobe;
+	du->mm = mm;
+	list_add(&du->list, &delayed_uprobe_list);
+	return 0;
+}
+
+static void delayed_uprobe_delete(struct delayed_uprobe *du)
+{
+	if (WARN_ON(!du))
+		return;
+	list_del(&du->list);
+	kfree(du);
+}
+
+static void delayed_uprobe_remove(struct uprobe *uprobe, struct mm_struct *mm)
+{
+	struct list_head *pos, *q;
+	struct delayed_uprobe *du;
+
+	if (!uprobe && !mm)
+		return;
+
+	list_for_each_safe(pos, q, &delayed_uprobe_list) {
+		du = list_entry(pos, struct delayed_uprobe, list);
+
+		if (uprobe && du->uprobe != uprobe)
+			continue;
+		if (mm && du->mm != mm)
+			continue;
+
+		delayed_uprobe_delete(du);
+	}
+}
+
+static bool valid_ref_ctr_vma(struct uprobe *uprobe,
+			      struct vm_area_struct *vma)
+{
+	unsigned long vaddr = offset_to_vaddr(vma, uprobe->ref_ctr_offset);
+
+	return uprobe->ref_ctr_offset &&
+		vma->vm_file &&
+		file_inode(vma->vm_file) == uprobe->inode &&
+		(vma->vm_flags & (VM_WRITE|VM_SHARED)) == VM_WRITE &&
+		vma->vm_start <= vaddr &&
+		vma->vm_end > vaddr;
+}
+
+static struct vm_area_struct *
+find_ref_ctr_vma(struct uprobe *uprobe, struct mm_struct *mm)
+{
+	VMA_ITERATOR(vmi, mm, 0);
+	struct vm_area_struct *tmp;
+
+	for_each_vma(vmi, tmp)
+		if (valid_ref_ctr_vma(uprobe, tmp))
+			return tmp;
+
+	return NULL;
+}
+
+static int
+__update_ref_ctr(struct mm_struct *mm, unsigned long vaddr, short d)
+{
+	void *kaddr;
+	struct page *page;
+	struct vm_area_struct *vma;
+	int ret;
+	short *ptr;
+
+	if (!vaddr || !d)
+		return -EINVAL;
+
+	ret = get_user_pages_remote(mm, vaddr, 1,
+			FOLL_WRITE, &page, &vma, NULL);
+	if (unlikely(ret <= 0)) {
+		/*
+		 * We are asking for 1 page. If get_user_pages_remote() fails,
+		 * it may return 0, in that case we have to return error.
+		 */
+		return ret == 0 ? -EBUSY : ret;
+	}
+
+	kaddr = kmap_atomic(page);
+	ptr = kaddr + (vaddr & ~PAGE_MASK);
+
+	if (unlikely(*ptr + d < 0)) {
+		pr_warn("ref_ctr going negative. vaddr: 0x%lx, "
+			"curr val: %d, delta: %d\n", vaddr, *ptr, d);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	*ptr += d;
+	ret = 0;
+out:
+	kunmap_atomic(kaddr);
+	put_page(page);
+	return ret;
+}
+
+static void update_ref_ctr_warn(struct uprobe *uprobe,
+				struct mm_struct *mm, short d)
+{
+	pr_warn("ref_ctr %s failed for inode: 0x%lx offset: "
+		"0x%llx ref_ctr_offset: 0x%llx of mm: 0x%pK\n",
+		d > 0 ? "increment" : "decrement", uprobe->inode->i_ino,
+		(unsigned long long) uprobe->offset,
+		(unsigned long long) uprobe->ref_ctr_offset, mm);
+}
+
+static int update_ref_ctr(struct uprobe *uprobe, struct mm_struct *mm,
+			  short d)
+{
+	struct vm_area_struct *rc_vma;
+	unsigned long rc_vaddr;
+	int ret = 0;
+
+	rc_vma = find_ref_ctr_vma(uprobe, mm);
+
+	if (rc_vma) {
+		rc_vaddr = offset_to_vaddr(rc_vma, uprobe->ref_ctr_offset);
+		ret = __update_ref_ctr(mm, rc_vaddr, d);
+		if (ret)
+			update_ref_ctr_warn(uprobe, mm, d);
+
+		if (d > 0)
+			return ret;
+	}
+
+	mutex_lock(&delayed_uprobe_lock);
+	if (d > 0)
+		ret = delayed_uprobe_add(uprobe, mm);
+	else
+		delayed_uprobe_remove(uprobe, mm);
+	mutex_unlock(&delayed_uprobe_lock);
+
+	return ret;
+}
+
+/*
+ * NOTE:
+ * Expect the breakpoint instruction to be the smallest size instruction for
+ * the architecture. If an arch has variable length instruction and the
+ * breakpoint instruction is not of the smallest length instruction
+ * supported by that architecture then we need to modify is_trap_at_addr and
+ * uprobe_write_opcode accordingly. This would never be a problem for archs
+ * that have fixed length instructions.
+ *
+ * uprobe_write_opcode - write the opcode at a given virtual address.
+ * @auprobe: arch specific probepoint information.
+ * @mm: the probed process address space.
+ * @vaddr: the virtual address to store the opcode.
+ * @opcode: opcode to be written at @vaddr.
+ *
+ * Called with mm->mmap_lock held for write.
+ * Return 0 (success) or a negative errno.
+ */
+int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
+			unsigned long vaddr, uprobe_opcode_t opcode)
+{
+	struct uprobe *uprobe;
+	struct page *old_page, *new_page;
+	struct vm_area_struct *vma;
+	int ret, is_register, ref_ctr_updated = 0;
+	bool orig_page_huge = false;
+	unsigned int gup_flags = FOLL_FORCE;
+
+	is_register = is_swbp_insn(&opcode);
+	uprobe = container_of(auprobe, struct uprobe, arch);
+
+retry:
+	if (is_register)
+		gup_flags |= FOLL_SPLIT_PMD;
+	/* Read the page with vaddr into memory */
+	ret = get_user_pages_remote(mm, vaddr, 1, gup_flags,
+				    &old_page, &vma, NULL);
+	if (ret <= 0)
+		return ret;
+
+	ret = verify_opcode(old_page, vaddr, &opcode);
+	if (ret <= 0)
+		goto put_old;
+
+	if (WARN(!is_register && PageCompound(old_page),
+		 "uprobe unregister should never work on compound page\n")) {
+		ret = -EINVAL;
+		goto put_old;
+	}
+
+	/* We are going to replace instruction, update ref_ctr. */
+	if (!ref_ctr_updated && uprobe->ref_ctr_offset) {
+		ret = update_ref_ctr(uprobe, mm, is_register ? 1 : -1);
+		if (ret)
+			goto put_old;
+
+		ref_ctr_updated = 1;
+	}
+
+	ret = 0;
+	if (!is_register && !PageAnon(old_page))
+		goto put_old;
+
+	ret = anon_vma_prepare(vma);
+	if (ret)
+		goto put_old;
+
+	ret = -ENOMEM;
+	new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr);
+	if (!new_page)
+		goto put_old;
+
+	__SetPageUptodate(new_page);
+	copy_highpage(new_page, old_page);
+	copy_to_page(new_page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
+
+	if (!is_register) {
+		struct page *orig_page;
+		pgoff_t index;
+
+		VM_BUG_ON_PAGE(!PageAnon(old_page), old_page);
+
+		index = vaddr_to_offset(vma, vaddr & PAGE_MASK) >> PAGE_SHIFT;
+		orig_page = find_get_page(vma->vm_file->f_inode->i_mapping,
+					  index);
+
+		if (orig_page) {
+			if (PageUptodate(orig_page) &&
+			    pages_identical(new_page, orig_page)) {
+				/* let go new_page */
+				put_page(new_page);
+				new_page = NULL;
+
+				if (PageCompound(orig_page))
+					orig_page_huge = true;
+			}
+			put_page(orig_page);
+		}
+	}
+
+	ret = __replace_page(vma, vaddr, old_page, new_page);
+	if (new_page)
+		put_page(new_page);
+put_old:
+	put_page(old_page);
+
+	if (unlikely(ret == -EAGAIN))
+		goto retry;
+
+	/* Revert back reference counter if instruction update failed. */
+	if (ret && is_register && ref_ctr_updated)
+		update_ref_ctr(uprobe, mm, -1);
+
+	/* try collapse pmd for compound page */
+	if (!ret && orig_page_huge)
+		collapse_pte_mapped_thp(mm, vaddr, false);
+
+	return ret;
+}
+
+/**
+ * set_swbp - store breakpoint at a given address.
+ * @auprobe: arch specific probepoint information.
+ * @mm: the probed process address space.
+ * @vaddr: the virtual address to insert the opcode.
+ *
+ * For mm @mm, store the breakpoint instruction at @vaddr.
+ * Return 0 (success) or a negative errno.
+ */
+int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
+{
+	return uprobe_write_opcode(auprobe, mm, vaddr, UPROBE_SWBP_INSN);
+}
+
+/**
+ * set_orig_insn - Restore the original instruction.
+ * @mm: the probed process address space.
+ * @auprobe: arch specific probepoint information.
+ * @vaddr: the virtual address to insert the opcode.
+ *
+ * For mm @mm, restore the original opcode (opcode) at @vaddr.
+ * Return 0 (success) or a negative errno.
+ */
+int __weak
+set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
+{
+	return uprobe_write_opcode(auprobe, mm, vaddr,
+			*(uprobe_opcode_t *)&auprobe->insn);
+}
+
+static struct uprobe *get_uprobe(struct uprobe *uprobe)
+{
+	refcount_inc(&uprobe->ref);
+	return uprobe;
+}
+
+static void put_uprobe(struct uprobe *uprobe)
+{
+	if (refcount_dec_and_test(&uprobe->ref)) {
+		/*
+		 * If application munmap(exec_vma) before uprobe_unregister()
+		 * gets called, we don't get a chance to remove uprobe from
+		 * delayed_uprobe_list from remove_breakpoint(). Do it here.
+		 */
+		mutex_lock(&delayed_uprobe_lock);
+		delayed_uprobe_remove(uprobe, NULL);
+		mutex_unlock(&delayed_uprobe_lock);
+		kfree(uprobe);
+	}
+}
+
+static __always_inline
+int uprobe_cmp(const struct inode *l_inode, const loff_t l_offset,
+	       const struct uprobe *r)
+{
+	if (l_inode < r->inode)
+		return -1;
+
+	if (l_inode > r->inode)
+		return 1;
+
+	if (l_offset < r->offset)
+		return -1;
+
+	if (l_offset > r->offset)
+		return 1;
+
+	return 0;
+}
+
+#define __node_2_uprobe(node) \
+	rb_entry((node), struct uprobe, rb_node)
+
+struct __uprobe_key {
+	struct inode *inode;
+	loff_t offset;
+};
+
+static inline int __uprobe_cmp_key(const void *key, const struct rb_node *b)
+{
+	const struct __uprobe_key *a = key;
+	return uprobe_cmp(a->inode, a->offset, __node_2_uprobe(b));
+}
+
+static inline int __uprobe_cmp(struct rb_node *a, const struct rb_node *b)
+{
+	struct uprobe *u = __node_2_uprobe(a);
+	return uprobe_cmp(u->inode, u->offset, __node_2_uprobe(b));
+}
+
+static struct uprobe *__find_uprobe(struct inode *inode, loff_t offset)
+{
+	struct __uprobe_key key = {
+		.inode = inode,
+		.offset = offset,
+	};
+	struct rb_node *node = rb_find(&key, &uprobes_tree, __uprobe_cmp_key);
+
+	if (node)
+		return get_uprobe(__node_2_uprobe(node));
+
+	return NULL;
+}
+
+/*
+ * Find a uprobe corresponding to a given inode:offset
+ * Acquires uprobes_treelock
+ */
+static struct uprobe *find_uprobe(struct inode *inode, loff_t offset)
+{
+	struct uprobe *uprobe;
+
+	spin_lock(&uprobes_treelock);
+	uprobe = __find_uprobe(inode, offset);
+	spin_unlock(&uprobes_treelock);
+
+	return uprobe;
+}
+
+static struct uprobe *__insert_uprobe(struct uprobe *uprobe)
+{
+	struct rb_node *node;
+
+	node = rb_find_add(&uprobe->rb_node, &uprobes_tree, __uprobe_cmp);
+	if (node)
+		return get_uprobe(__node_2_uprobe(node));
+
+	/* get access + creation ref */
+	refcount_set(&uprobe->ref, 2);
+	return NULL;
+}
+
+/*
+ * Acquire uprobes_treelock.
+ * Matching uprobe already exists in rbtree;
+ *	increment (access refcount) and return the matching uprobe.
+ *
+ * No matching uprobe; insert the uprobe in rb_tree;
+ *	get a double refcount (access + creation) and return NULL.
+ */
+static struct uprobe *insert_uprobe(struct uprobe *uprobe)
+{
+	struct uprobe *u;
+
+	spin_lock(&uprobes_treelock);
+	u = __insert_uprobe(uprobe);
+	spin_unlock(&uprobes_treelock);
+
+	return u;
+}
+
+static void
+ref_ctr_mismatch_warn(struct uprobe *cur_uprobe, struct uprobe *uprobe)
+{
+	pr_warn("ref_ctr_offset mismatch. inode: 0x%lx offset: 0x%llx "
+		"ref_ctr_offset(old): 0x%llx ref_ctr_offset(new): 0x%llx\n",
+		uprobe->inode->i_ino, (unsigned long long) uprobe->offset,
+		(unsigned long long) cur_uprobe->ref_ctr_offset,
+		(unsigned long long) uprobe->ref_ctr_offset);
+}
+
+static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset,
+				   loff_t ref_ctr_offset)
+{
+	struct uprobe *uprobe, *cur_uprobe;
+
+	uprobe = kzalloc(sizeof(struct uprobe), GFP_KERNEL);
+	if (!uprobe)
+		return NULL;
+
+	uprobe->inode = inode;
+	uprobe->offset = offset;
+	uprobe->ref_ctr_offset = ref_ctr_offset;
+	init_rwsem(&uprobe->register_rwsem);
+	init_rwsem(&uprobe->consumer_rwsem);
+
+	/* add to uprobes_tree, sorted on inode:offset */
+	cur_uprobe = insert_uprobe(uprobe);
+	/* a uprobe exists for this inode:offset combination */
+	if (cur_uprobe) {
+		if (cur_uprobe->ref_ctr_offset != uprobe->ref_ctr_offset) {
+			ref_ctr_mismatch_warn(cur_uprobe, uprobe);
+			put_uprobe(cur_uprobe);
+			kfree(uprobe);
+			return ERR_PTR(-EINVAL);
+		}
+		kfree(uprobe);
+		uprobe = cur_uprobe;
+	}
+
+	return uprobe;
+}
+
+static void consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc)
+{
+	down_write(&uprobe->consumer_rwsem);
+	uc->next = uprobe->consumers;
+	uprobe->consumers = uc;
+	up_write(&uprobe->consumer_rwsem);
+}
+
+/*
+ * For uprobe @uprobe, delete the consumer @uc.
+ * Return true if the @uc is deleted successfully
+ * or return false.
+ */
+static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc)
+{
+	struct uprobe_consumer **con;
+	bool ret = false;
+
+	down_write(&uprobe->consumer_rwsem);
+	for (con = &uprobe->consumers; *con; con = &(*con)->next) {
+		if (*con == uc) {
+			*con = uc->next;
+			ret = true;
+			break;
+		}
+	}
+	up_write(&uprobe->consumer_rwsem);
+
+	return ret;
+}
+
+static int __copy_insn(struct address_space *mapping, struct file *filp,
+			void *insn, int nbytes, loff_t offset)
+{
+	struct page *page;
+	/*
+	 * Ensure that the page that has the original instruction is populated
+	 * and in page-cache. If ->read_folio == NULL it must be shmem_mapping(),
+	 * see uprobe_register().
+	 */
+	if (mapping->a_ops->read_folio)
+		page = read_mapping_page(mapping, offset >> PAGE_SHIFT, filp);
+	else
+		page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT);
+	if (IS_ERR(page))
+		return PTR_ERR(page);
+
+	copy_from_page(page, offset, insn, nbytes);
+	put_page(page);
+
+	return 0;
+}
+
+static int copy_insn(struct uprobe *uprobe, struct file *filp)
+{
+	struct address_space *mapping = uprobe->inode->i_mapping;
+	loff_t offs = uprobe->offset;
+	void *insn = &uprobe->arch.insn;
+	int size = sizeof(uprobe->arch.insn);
+	int len, err = -EIO;
+
+	/* Copy only available bytes, -EIO if nothing was read */
+	do {
+		if (offs >= i_size_read(uprobe->inode))
+			break;
+
+		len = min_t(int, size, PAGE_SIZE - (offs & ~PAGE_MASK));
+		err = __copy_insn(mapping, filp, insn, len, offs);
+		if (err)
+			break;
+
+		insn += len;
+		offs += len;
+		size -= len;
+	} while (size);
+
+	return err;
+}
+
+static int prepare_uprobe(struct uprobe *uprobe, struct file *file,
+				struct mm_struct *mm, unsigned long vaddr)
+{
+	int ret = 0;
+
+	if (test_bit(UPROBE_COPY_INSN, &uprobe->flags))
+		return ret;
+
+	/* TODO: move this into _register, until then we abuse this sem. */
+	down_write(&uprobe->consumer_rwsem);
+	if (test_bit(UPROBE_COPY_INSN, &uprobe->flags))
+		goto out;
+
+	ret = copy_insn(uprobe, file);
+	if (ret)
+		goto out;
+
+	ret = -ENOTSUPP;
+	if (is_trap_insn((uprobe_opcode_t *)&uprobe->arch.insn))
+		goto out;
+
+	ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr);
+	if (ret)
+		goto out;
+
+	smp_wmb(); /* pairs with the smp_rmb() in handle_swbp() */
+	set_bit(UPROBE_COPY_INSN, &uprobe->flags);
+
+ out:
+	up_write(&uprobe->consumer_rwsem);
+
+	return ret;
+}
+
+static inline bool consumer_filter(struct uprobe_consumer *uc,
+				   enum uprobe_filter_ctx ctx, struct mm_struct *mm)
+{
+	return !uc->filter || uc->filter(uc, ctx, mm);
+}
+
+static bool filter_chain(struct uprobe *uprobe,
+			 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
+{
+	struct uprobe_consumer *uc;
+	bool ret = false;
+
+	down_read(&uprobe->consumer_rwsem);
+	for (uc = uprobe->consumers; uc; uc = uc->next) {
+		ret = consumer_filter(uc, ctx, mm);
+		if (ret)
+			break;
+	}
+	up_read(&uprobe->consumer_rwsem);
+
+	return ret;
+}
+
+static int
+install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
+			struct vm_area_struct *vma, unsigned long vaddr)
+{
+	bool first_uprobe;
+	int ret;
+
+	ret = prepare_uprobe(uprobe, vma->vm_file, mm, vaddr);
+	if (ret)
+		return ret;
+
+	/*
+	 * set MMF_HAS_UPROBES in advance for uprobe_pre_sstep_notifier(),
+	 * the task can hit this breakpoint right after __replace_page().
+	 */
+	first_uprobe = !test_bit(MMF_HAS_UPROBES, &mm->flags);
+	if (first_uprobe)
+		set_bit(MMF_HAS_UPROBES, &mm->flags);
+
+	ret = set_swbp(&uprobe->arch, mm, vaddr);
+	if (!ret)
+		clear_bit(MMF_RECALC_UPROBES, &mm->flags);
+	else if (first_uprobe)
+		clear_bit(MMF_HAS_UPROBES, &mm->flags);
+
+	return ret;
+}
+
+static int
+remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vaddr)
+{
+	set_bit(MMF_RECALC_UPROBES, &mm->flags);
+	return set_orig_insn(&uprobe->arch, mm, vaddr);
+}
+
+static inline bool uprobe_is_active(struct uprobe *uprobe)
+{
+	return !RB_EMPTY_NODE(&uprobe->rb_node);
+}
+/*
+ * There could be threads that have already hit the breakpoint. They
+ * will recheck the current insn and restart if find_uprobe() fails.
+ * See find_active_uprobe().
+ */
+static void delete_uprobe(struct uprobe *uprobe)
+{
+	if (WARN_ON(!uprobe_is_active(uprobe)))
+		return;
+
+	spin_lock(&uprobes_treelock);
+	rb_erase(&uprobe->rb_node, &uprobes_tree);
+	spin_unlock(&uprobes_treelock);
+	RB_CLEAR_NODE(&uprobe->rb_node); /* for uprobe_is_active() */
+	put_uprobe(uprobe);
+}
+
+struct map_info {
+	struct map_info *next;
+	struct mm_struct *mm;
+	unsigned long vaddr;
+};
+
+static inline struct map_info *free_map_info(struct map_info *info)
+{
+	struct map_info *next = info->next;
+	kfree(info);
+	return next;
+}
+
+static struct map_info *
+build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
+{
+	unsigned long pgoff = offset >> PAGE_SHIFT;
+	struct vm_area_struct *vma;
+	struct map_info *curr = NULL;
+	struct map_info *prev = NULL;
+	struct map_info *info;
+	int more = 0;
+
+ again:
+	i_mmap_lock_read(mapping);
+	vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
+		if (!valid_vma(vma, is_register))
+			continue;
+
+		if (!prev && !more) {
+			/*
+			 * Needs GFP_NOWAIT to avoid i_mmap_rwsem recursion through
+			 * reclaim. This is optimistic, no harm done if it fails.
+			 */
+			prev = kmalloc(sizeof(struct map_info),
+					GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN);
+			if (prev)
+				prev->next = NULL;
+		}
+		if (!prev) {
+			more++;
+			continue;
+		}
+
+		if (!mmget_not_zero(vma->vm_mm))
+			continue;
+
+		info = prev;
+		prev = prev->next;
+		info->next = curr;
+		curr = info;
+
+		info->mm = vma->vm_mm;
+		info->vaddr = offset_to_vaddr(vma, offset);
+	}
+	i_mmap_unlock_read(mapping);
+
+	if (!more)
+		goto out;
+
+	prev = curr;
+	while (curr) {
+		mmput(curr->mm);
+		curr = curr->next;
+	}
+
+	do {
+		info = kmalloc(sizeof(struct map_info), GFP_KERNEL);
+		if (!info) {
+			curr = ERR_PTR(-ENOMEM);
+			goto out;
+		}
+		info->next = prev;
+		prev = info;
+	} while (--more);
+
+	goto again;
+ out:
+	while (prev)
+		prev = free_map_info(prev);
+	return curr;
+}
+
+static int
+register_for_each_vma(struct uprobe *uprobe, struct uprobe_consumer *new)
+{
+	bool is_register = !!new;
+	struct map_info *info;
+	int err = 0;
+
+	percpu_down_write(&dup_mmap_sem);
+	info = build_map_info(uprobe->inode->i_mapping,
+					uprobe->offset, is_register);
+	if (IS_ERR(info)) {
+		err = PTR_ERR(info);
+		goto out;
+	}
+
+	while (info) {
+		struct mm_struct *mm = info->mm;
+		struct vm_area_struct *vma;
+
+		if (err && is_register)
+			goto free;
+
+		mmap_write_lock(mm);
+		vma = find_vma(mm, info->vaddr);
+		if (!vma || !valid_vma(vma, is_register) ||
+		    file_inode(vma->vm_file) != uprobe->inode)
+			goto unlock;
+
+		if (vma->vm_start > info->vaddr ||
+		    vaddr_to_offset(vma, info->vaddr) != uprobe->offset)
+			goto unlock;
+
+		if (is_register) {
+			/* consult only the "caller", new consumer. */
+			if (consumer_filter(new,
+					UPROBE_FILTER_REGISTER, mm))
+				err = install_breakpoint(uprobe, mm, vma, info->vaddr);
+		} else if (test_bit(MMF_HAS_UPROBES, &mm->flags)) {
+			if (!filter_chain(uprobe,
+					UPROBE_FILTER_UNREGISTER, mm))
+				err |= remove_breakpoint(uprobe, mm, info->vaddr);
+		}
+
+ unlock:
+		mmap_write_unlock(mm);
+ free:
+		mmput(mm);
+		info = free_map_info(info);
+	}
+ out:
+	percpu_up_write(&dup_mmap_sem);
+	return err;
+}
+
+static void
+__uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *uc)
+{
+	int err;
+
+	if (WARN_ON(!consumer_del(uprobe, uc)))
+		return;
+
+	err = register_for_each_vma(uprobe, NULL);
+	/* TODO : cant unregister? schedule a worker thread */
+	if (!uprobe->consumers && !err)
+		delete_uprobe(uprobe);
+}
+
+/*
+ * uprobe_unregister - unregister an already registered probe.
+ * @inode: the file in which the probe has to be removed.
+ * @offset: offset from the start of the file.
+ * @uc: identify which probe if multiple probes are colocated.
+ */
+void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
+{
+	struct uprobe *uprobe;
+
+	uprobe = find_uprobe(inode, offset);
+	if (WARN_ON(!uprobe))
+		return;
+
+	down_write(&uprobe->register_rwsem);
+	__uprobe_unregister(uprobe, uc);
+	up_write(&uprobe->register_rwsem);
+	put_uprobe(uprobe);
+}
+EXPORT_SYMBOL_GPL(uprobe_unregister);
+
+/*
+ * __uprobe_register - register a probe
+ * @inode: the file in which the probe has to be placed.
+ * @offset: offset from the start of the file.
+ * @uc: information on howto handle the probe..
+ *
+ * Apart from the access refcount, __uprobe_register() takes a creation
+ * refcount (thro alloc_uprobe) if and only if this @uprobe is getting
+ * inserted into the rbtree (i.e first consumer for a @inode:@offset
+ * tuple).  Creation refcount stops uprobe_unregister from freeing the
+ * @uprobe even before the register operation is complete. Creation
+ * refcount is released when the last @uc for the @uprobe
+ * unregisters. Caller of __uprobe_register() is required to keep @inode
+ * (and the containing mount) referenced.
+ *
+ * Return errno if it cannot successully install probes
+ * else return 0 (success)
+ */
+static int __uprobe_register(struct inode *inode, loff_t offset,
+			     loff_t ref_ctr_offset, struct uprobe_consumer *uc)
+{
+	struct uprobe *uprobe;
+	int ret;
+
+	/* Uprobe must have at least one set consumer */
+	if (!uc->handler && !uc->ret_handler)
+		return -EINVAL;
+
+	/* copy_insn() uses read_mapping_page() or shmem_read_mapping_page() */
+	if (!inode->i_mapping->a_ops->read_folio &&
+	    !shmem_mapping(inode->i_mapping))
+		return -EIO;
+	/* Racy, just to catch the obvious mistakes */
+	if (offset > i_size_read(inode))
+		return -EINVAL;
+
+	/*
+	 * This ensures that copy_from_page(), copy_to_page() and
+	 * __update_ref_ctr() can't cross page boundary.
+	 */
+	if (!IS_ALIGNED(offset, UPROBE_SWBP_INSN_SIZE))
+		return -EINVAL;
+	if (!IS_ALIGNED(ref_ctr_offset, sizeof(short)))
+		return -EINVAL;
+
+ retry:
+	uprobe = alloc_uprobe(inode, offset, ref_ctr_offset);
+	if (!uprobe)
+		return -ENOMEM;
+	if (IS_ERR(uprobe))
+		return PTR_ERR(uprobe);
+
+	/*
+	 * We can race with uprobe_unregister()->delete_uprobe().
+	 * Check uprobe_is_active() and retry if it is false.
+	 */
+	down_write(&uprobe->register_rwsem);
+	ret = -EAGAIN;
+	if (likely(uprobe_is_active(uprobe))) {
+		consumer_add(uprobe, uc);
+		ret = register_for_each_vma(uprobe, uc);
+		if (ret)
+			__uprobe_unregister(uprobe, uc);
+	}
+	up_write(&uprobe->register_rwsem);
+	put_uprobe(uprobe);
+
+	if (unlikely(ret == -EAGAIN))
+		goto retry;
+	return ret;
+}
+
+int uprobe_register(struct inode *inode, loff_t offset,
+		    struct uprobe_consumer *uc)
+{
+	return __uprobe_register(inode, offset, 0, uc);
+}
+EXPORT_SYMBOL_GPL(uprobe_register);
+
+int uprobe_register_refctr(struct inode *inode, loff_t offset,
+			   loff_t ref_ctr_offset, struct uprobe_consumer *uc)
+{
+	return __uprobe_register(inode, offset, ref_ctr_offset, uc);
+}
+EXPORT_SYMBOL_GPL(uprobe_register_refctr);
+
+/*
+ * uprobe_apply - unregister an already registered probe.
+ * @inode: the file in which the probe has to be removed.
+ * @offset: offset from the start of the file.
+ * @uc: consumer which wants to add more or remove some breakpoints
+ * @add: add or remove the breakpoints
+ */
+int uprobe_apply(struct inode *inode, loff_t offset,
+			struct uprobe_consumer *uc, bool add)
+{
+	struct uprobe *uprobe;
+	struct uprobe_consumer *con;
+	int ret = -ENOENT;
+
+	uprobe = find_uprobe(inode, offset);
+	if (WARN_ON(!uprobe))
+		return ret;
+
+	down_write(&uprobe->register_rwsem);
+	for (con = uprobe->consumers; con && con != uc ; con = con->next)
+		;
+	if (con)
+		ret = register_for_each_vma(uprobe, add ? uc : NULL);
+	up_write(&uprobe->register_rwsem);
+	put_uprobe(uprobe);
+
+	return ret;
+}
+
+static int unapply_uprobe(struct uprobe *uprobe, struct mm_struct *mm)
+{
+	VMA_ITERATOR(vmi, mm, 0);
+	struct vm_area_struct *vma;
+	int err = 0;
+
+	mmap_read_lock(mm);
+	for_each_vma(vmi, vma) {
+		unsigned long vaddr;
+		loff_t offset;
+
+		if (!valid_vma(vma, false) ||
+		    file_inode(vma->vm_file) != uprobe->inode)
+			continue;
+
+		offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
+		if (uprobe->offset <  offset ||
+		    uprobe->offset >= offset + vma->vm_end - vma->vm_start)
+			continue;
+
+		vaddr = offset_to_vaddr(vma, uprobe->offset);
+		err |= remove_breakpoint(uprobe, mm, vaddr);
+	}
+	mmap_read_unlock(mm);
+
+	return err;
+}
+
+static struct rb_node *
+find_node_in_range(struct inode *inode, loff_t min, loff_t max)
+{
+	struct rb_node *n = uprobes_tree.rb_node;
+
+	while (n) {
+		struct uprobe *u = rb_entry(n, struct uprobe, rb_node);
+
+		if (inode < u->inode) {
+			n = n->rb_left;
+		} else if (inode > u->inode) {
+			n = n->rb_right;
+		} else {
+			if (max < u->offset)
+				n = n->rb_left;
+			else if (min > u->offset)
+				n = n->rb_right;
+			else
+				break;
+		}
+	}
+
+	return n;
+}
+
+/*
+ * For a given range in vma, build a list of probes that need to be inserted.
+ */
+static void build_probe_list(struct inode *inode,
+				struct vm_area_struct *vma,
+				unsigned long start, unsigned long end,
+				struct list_head *head)
+{
+	loff_t min, max;
+	struct rb_node *n, *t;
+	struct uprobe *u;
+
+	INIT_LIST_HEAD(head);
+	min = vaddr_to_offset(vma, start);
+	max = min + (end - start) - 1;
+
+	spin_lock(&uprobes_treelock);
+	n = find_node_in_range(inode, min, max);
+	if (n) {
+		for (t = n; t; t = rb_prev(t)) {
+			u = rb_entry(t, struct uprobe, rb_node);
+			if (u->inode != inode || u->offset < min)
+				break;
+			list_add(&u->pending_list, head);
+			get_uprobe(u);
+		}
+		for (t = n; (t = rb_next(t)); ) {
+			u = rb_entry(t, struct uprobe, rb_node);
+			if (u->inode != inode || u->offset > max)
+				break;
+			list_add(&u->pending_list, head);
+			get_uprobe(u);
+		}
+	}
+	spin_unlock(&uprobes_treelock);
+}
+
+/* @vma contains reference counter, not the probed instruction. */
+static int delayed_ref_ctr_inc(struct vm_area_struct *vma)
+{
+	struct list_head *pos, *q;
+	struct delayed_uprobe *du;
+	unsigned long vaddr;
+	int ret = 0, err = 0;
+
+	mutex_lock(&delayed_uprobe_lock);
+	list_for_each_safe(pos, q, &delayed_uprobe_list) {
+		du = list_entry(pos, struct delayed_uprobe, list);
+
+		if (du->mm != vma->vm_mm ||
+		    !valid_ref_ctr_vma(du->uprobe, vma))
+			continue;
+
+		vaddr = offset_to_vaddr(vma, du->uprobe->ref_ctr_offset);
+		ret = __update_ref_ctr(vma->vm_mm, vaddr, 1);
+		if (ret) {
+			update_ref_ctr_warn(du->uprobe, vma->vm_mm, 1);
+			if (!err)
+				err = ret;
+		}
+		delayed_uprobe_delete(du);
+	}
+	mutex_unlock(&delayed_uprobe_lock);
+	return err;
+}
+
+/*
+ * Called from mmap_region/vma_adjust with mm->mmap_lock acquired.
+ *
+ * Currently we ignore all errors and always return 0, the callers
+ * can't handle the failure anyway.
+ */
+int uprobe_mmap(struct vm_area_struct *vma)
+{
+	struct list_head tmp_list;
+	struct uprobe *uprobe, *u;
+	struct inode *inode;
+
+	if (no_uprobe_events())
+		return 0;
+
+	if (vma->vm_file &&
+	    (vma->vm_flags & (VM_WRITE|VM_SHARED)) == VM_WRITE &&
+	    test_bit(MMF_HAS_UPROBES, &vma->vm_mm->flags))
+		delayed_ref_ctr_inc(vma);
+
+	if (!valid_vma(vma, true))
+		return 0;
+
+	inode = file_inode(vma->vm_file);
+	if (!inode)
+		return 0;
+
+	mutex_lock(uprobes_mmap_hash(inode));
+	build_probe_list(inode, vma, vma->vm_start, vma->vm_end, &tmp_list);
+	/*
+	 * We can race with uprobe_unregister(), this uprobe can be already
+	 * removed. But in this case filter_chain() must return false, all
+	 * consumers have gone away.
+	 */
+	list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
+		if (!fatal_signal_pending(current) &&
+		    filter_chain(uprobe, UPROBE_FILTER_MMAP, vma->vm_mm)) {
+			unsigned long vaddr = offset_to_vaddr(vma, uprobe->offset);
+			install_breakpoint(uprobe, vma->vm_mm, vma, vaddr);
+		}
+		put_uprobe(uprobe);
+	}
+	mutex_unlock(uprobes_mmap_hash(inode));
+
+	return 0;
+}
+
+static bool
+vma_has_uprobes(struct vm_area_struct *vma, unsigned long start, unsigned long end)
+{
+	loff_t min, max;
+	struct inode *inode;
+	struct rb_node *n;
+
+	inode = file_inode(vma->vm_file);
+
+	min = vaddr_to_offset(vma, start);
+	max = min + (end - start) - 1;
+
+	spin_lock(&uprobes_treelock);
+	n = find_node_in_range(inode, min, max);
+	spin_unlock(&uprobes_treelock);
+
+	return !!n;
+}
+
+/*
+ * Called in context of a munmap of a vma.
+ */
+void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end)
+{
+	if (no_uprobe_events() || !valid_vma(vma, false))
+		return;
+
+	if (!atomic_read(&vma->vm_mm->mm_users)) /* called by mmput() ? */
+		return;
+
+	if (!test_bit(MMF_HAS_UPROBES, &vma->vm_mm->flags) ||
+	     test_bit(MMF_RECALC_UPROBES, &vma->vm_mm->flags))
+		return;
+
+	if (vma_has_uprobes(vma, start, end))
+		set_bit(MMF_RECALC_UPROBES, &vma->vm_mm->flags);
+}
+
+/* Slot allocation for XOL */
+static int xol_add_vma(struct mm_struct *mm, struct xol_area *area)
+{
+	struct vm_area_struct *vma;
+	int ret;
+
+	if (mmap_write_lock_killable(mm))
+		return -EINTR;
+
+	if (mm->uprobes_state.xol_area) {
+		ret = -EALREADY;
+		goto fail;
+	}
+
+	if (!area->vaddr) {
+		/* Try to map as high as possible, this is only a hint. */
+		area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE,
+						PAGE_SIZE, 0, 0);
+		if (IS_ERR_VALUE(area->vaddr)) {
+			ret = area->vaddr;
+			goto fail;
+		}
+	}
+
+	vma = _install_special_mapping(mm, area->vaddr, PAGE_SIZE,
+				VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO,
+				&area->xol_mapping);
+	if (IS_ERR(vma)) {
+		ret = PTR_ERR(vma);
+		goto fail;
+	}
+
+	ret = 0;
+	/* pairs with get_xol_area() */
+	smp_store_release(&mm->uprobes_state.xol_area, area); /* ^^^ */
+ fail:
+	mmap_write_unlock(mm);
+
+	return ret;
+}
+
+static struct xol_area *__create_xol_area(unsigned long vaddr)
+{
+	struct mm_struct *mm = current->mm;
+	uprobe_opcode_t insn = UPROBE_SWBP_INSN;
+	struct xol_area *area;
+
+	area = kmalloc(sizeof(*area), GFP_KERNEL);
+	if (unlikely(!area))
+		goto out;
+
+	area->bitmap = kcalloc(BITS_TO_LONGS(UINSNS_PER_PAGE), sizeof(long),
+			       GFP_KERNEL);
+	if (!area->bitmap)
+		goto free_area;
+
+	area->xol_mapping.name = "[uprobes]";
+	area->xol_mapping.fault = NULL;
+	area->xol_mapping.pages = area->pages;
+	area->pages[0] = alloc_page(GFP_HIGHUSER);
+	if (!area->pages[0])
+		goto free_bitmap;
+	area->pages[1] = NULL;
+
+	area->vaddr = vaddr;
+	init_waitqueue_head(&area->wq);
+	/* Reserve the 1st slot for get_trampoline_vaddr() */
+	set_bit(0, area->bitmap);
+	atomic_set(&area->slot_count, 1);
+	arch_uprobe_copy_ixol(area->pages[0], 0, &insn, UPROBE_SWBP_INSN_SIZE);
+
+	if (!xol_add_vma(mm, area))
+		return area;
+
+	__free_page(area->pages[0]);
+ free_bitmap:
+	kfree(area->bitmap);
+ free_area:
+	kfree(area);
+ out:
+	return NULL;
+}
+
+/*
+ * get_xol_area - Allocate process's xol_area if necessary.
+ * This area will be used for storing instructions for execution out of line.
+ *
+ * Returns the allocated area or NULL.
+ */
+static struct xol_area *get_xol_area(void)
+{
+	struct mm_struct *mm = current->mm;
+	struct xol_area *area;
+
+	if (!mm->uprobes_state.xol_area)
+		__create_xol_area(0);
+
+	/* Pairs with xol_add_vma() smp_store_release() */
+	area = READ_ONCE(mm->uprobes_state.xol_area); /* ^^^ */
+	return area;
+}
+
+/*
+ * uprobe_clear_state - Free the area allocated for slots.
+ */
+void uprobe_clear_state(struct mm_struct *mm)
+{
+	struct xol_area *area = mm->uprobes_state.xol_area;
+
+	mutex_lock(&delayed_uprobe_lock);
+	delayed_uprobe_remove(NULL, mm);
+	mutex_unlock(&delayed_uprobe_lock);
+
+	if (!area)
+		return;
+
+	put_page(area->pages[0]);
+	kfree(area->bitmap);
+	kfree(area);
+}
+
+void uprobe_start_dup_mmap(void)
+{
+	percpu_down_read(&dup_mmap_sem);
+}
+
+void uprobe_end_dup_mmap(void)
+{
+	percpu_up_read(&dup_mmap_sem);
+}
+
+void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm)
+{
+	if (test_bit(MMF_HAS_UPROBES, &oldmm->flags)) {
+		set_bit(MMF_HAS_UPROBES, &newmm->flags);
+		/* unconditionally, dup_mmap() skips VM_DONTCOPY vmas */
+		set_bit(MMF_RECALC_UPROBES, &newmm->flags);
+	}
+}
+
+/*
+ *  - search for a free slot.
+ */
+static unsigned long xol_take_insn_slot(struct xol_area *area)
+{
+	unsigned long slot_addr;
+	int slot_nr;
+
+	do {
+		slot_nr = find_first_zero_bit(area->bitmap, UINSNS_PER_PAGE);
+		if (slot_nr < UINSNS_PER_PAGE) {
+			if (!test_and_set_bit(slot_nr, area->bitmap))
+				break;
+
+			slot_nr = UINSNS_PER_PAGE;
+			continue;
+		}
+		wait_event(area->wq, (atomic_read(&area->slot_count) < UINSNS_PER_PAGE));
+	} while (slot_nr >= UINSNS_PER_PAGE);
+
+	slot_addr = area->vaddr + (slot_nr * UPROBE_XOL_SLOT_BYTES);
+	atomic_inc(&area->slot_count);
+
+	return slot_addr;
+}
+
+/*
+ * xol_get_insn_slot - allocate a slot for xol.
+ * Returns the allocated slot address or 0.
+ */
+static unsigned long xol_get_insn_slot(struct uprobe *uprobe)
+{
+	struct xol_area *area;
+	unsigned long xol_vaddr;
+
+	area = get_xol_area();
+	if (!area)
+		return 0;
+
+	xol_vaddr = xol_take_insn_slot(area);
+	if (unlikely(!xol_vaddr))
+		return 0;
+
+	arch_uprobe_copy_ixol(area->pages[0], xol_vaddr,
+			      &uprobe->arch.ixol, sizeof(uprobe->arch.ixol));
+
+	return xol_vaddr;
+}
+
+/*
+ * xol_free_insn_slot - If slot was earlier allocated by
+ * @xol_get_insn_slot(), make the slot available for
+ * subsequent requests.
+ */
+static void xol_free_insn_slot(struct task_struct *tsk)
+{
+	struct xol_area *area;
+	unsigned long vma_end;
+	unsigned long slot_addr;
+
+	if (!tsk->mm || !tsk->mm->uprobes_state.xol_area || !tsk->utask)
+		return;
+
+	slot_addr = tsk->utask->xol_vaddr;
+	if (unlikely(!slot_addr))
+		return;
+
+	area = tsk->mm->uprobes_state.xol_area;
+	vma_end = area->vaddr + PAGE_SIZE;
+	if (area->vaddr <= slot_addr && slot_addr < vma_end) {
+		unsigned long offset;
+		int slot_nr;
+
+		offset = slot_addr - area->vaddr;
+		slot_nr = offset / UPROBE_XOL_SLOT_BYTES;
+		if (slot_nr >= UINSNS_PER_PAGE)
+			return;
+
+		clear_bit(slot_nr, area->bitmap);
+		atomic_dec(&area->slot_count);
+		smp_mb__after_atomic(); /* pairs with prepare_to_wait() */
+		if (waitqueue_active(&area->wq))
+			wake_up(&area->wq);
+
+		tsk->utask->xol_vaddr = 0;
+	}
+}
+
+void __weak arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
+				  void *src, unsigned long len)
+{
+	/* Initialize the slot */
+	copy_to_page(page, vaddr, src, len);
+
+	/*
+	 * We probably need flush_icache_user_page() but it needs vma.
+	 * This should work on most of architectures by default. If
+	 * architecture needs to do something different it can define
+	 * its own version of the function.
+	 */
+	flush_dcache_page(page);
+}
+
+/**
+ * uprobe_get_swbp_addr - compute address of swbp given post-swbp regs
+ * @regs: Reflects the saved state of the task after it has hit a breakpoint
+ * instruction.
+ * Return the address of the breakpoint instruction.
+ */
+unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs)
+{
+	return instruction_pointer(regs) - UPROBE_SWBP_INSN_SIZE;
+}
+
+unsigned long uprobe_get_trap_addr(struct pt_regs *regs)
+{
+	struct uprobe_task *utask = current->utask;
+
+	if (unlikely(utask && utask->active_uprobe))
+		return utask->vaddr;
+
+	return instruction_pointer(regs);
+}
+
+static struct return_instance *free_ret_instance(struct return_instance *ri)
+{
+	struct return_instance *next = ri->next;
+	put_uprobe(ri->uprobe);
+	kfree(ri);
+	return next;
+}
+
+/*
+ * Called with no locks held.
+ * Called in context of an exiting or an exec-ing thread.
+ */
+void uprobe_free_utask(struct task_struct *t)
+{
+	struct uprobe_task *utask = t->utask;
+	struct return_instance *ri;
+
+	if (!utask)
+		return;
+
+	if (utask->active_uprobe)
+		put_uprobe(utask->active_uprobe);
+
+	ri = utask->return_instances;
+	while (ri)
+		ri = free_ret_instance(ri);
+
+	xol_free_insn_slot(t);
+	kfree(utask);
+	t->utask = NULL;
+}
+
+/*
+ * Allocate a uprobe_task object for the task if necessary.
+ * Called when the thread hits a breakpoint.
+ *
+ * Returns:
+ * - pointer to new uprobe_task on success
+ * - NULL otherwise
+ */
+static struct uprobe_task *get_utask(void)
+{
+	if (!current->utask)
+		current->utask = kzalloc(sizeof(struct uprobe_task), GFP_KERNEL);
+	return current->utask;
+}
+
+static int dup_utask(struct task_struct *t, struct uprobe_task *o_utask)
+{
+	struct uprobe_task *n_utask;
+	struct return_instance **p, *o, *n;
+
+	n_utask = kzalloc(sizeof(struct uprobe_task), GFP_KERNEL);
+	if (!n_utask)
+		return -ENOMEM;
+	t->utask = n_utask;
+
+	p = &n_utask->return_instances;
+	for (o = o_utask->return_instances; o; o = o->next) {
+		n = kmalloc(sizeof(struct return_instance), GFP_KERNEL);
+		if (!n)
+			return -ENOMEM;
+
+		*n = *o;
+		get_uprobe(n->uprobe);
+		n->next = NULL;
+
+		*p = n;
+		p = &n->next;
+		n_utask->depth++;
+	}
+
+	return 0;
+}
+
+static void uprobe_warn(struct task_struct *t, const char *msg)
+{
+	pr_warn("uprobe: %s:%d failed to %s\n",
+			current->comm, current->pid, msg);
+}
+
+static void dup_xol_work(struct callback_head *work)
+{
+	if (current->flags & PF_EXITING)
+		return;
+
+	if (!__create_xol_area(current->utask->dup_xol_addr) &&
+			!fatal_signal_pending(current))
+		uprobe_warn(current, "dup xol area");
+}
+
+/*
+ * Called in context of a new clone/fork from copy_process.
+ */
+void uprobe_copy_process(struct task_struct *t, unsigned long flags)
+{
+	struct uprobe_task *utask = current->utask;
+	struct mm_struct *mm = current->mm;
+	struct xol_area *area;
+
+	t->utask = NULL;
+
+	if (!utask || !utask->return_instances)
+		return;
+
+	if (mm == t->mm && !(flags & CLONE_VFORK))
+		return;
+
+	if (dup_utask(t, utask))
+		return uprobe_warn(t, "dup ret instances");
+
+	/* The task can fork() after dup_xol_work() fails */
+	area = mm->uprobes_state.xol_area;
+	if (!area)
+		return uprobe_warn(t, "dup xol area");
+
+	if (mm == t->mm)
+		return;
+
+	t->utask->dup_xol_addr = area->vaddr;
+	init_task_work(&t->utask->dup_xol_work, dup_xol_work);
+	task_work_add(t, &t->utask->dup_xol_work, TWA_RESUME);
+}
+
+/*
+ * Current area->vaddr notion assume the trampoline address is always
+ * equal area->vaddr.
+ *
+ * Returns -1 in case the xol_area is not allocated.
+ */
+static unsigned long get_trampoline_vaddr(void)
+{
+	struct xol_area *area;
+	unsigned long trampoline_vaddr = -1;
+
+	/* Pairs with xol_add_vma() smp_store_release() */
+	area = READ_ONCE(current->mm->uprobes_state.xol_area); /* ^^^ */
+	if (area)
+		trampoline_vaddr = area->vaddr;
+
+	return trampoline_vaddr;
+}
+
+static void cleanup_return_instances(struct uprobe_task *utask, bool chained,
+					struct pt_regs *regs)
+{
+	struct return_instance *ri = utask->return_instances;
+	enum rp_check ctx = chained ? RP_CHECK_CHAIN_CALL : RP_CHECK_CALL;
+
+	while (ri && !arch_uretprobe_is_alive(ri, ctx, regs)) {
+		ri = free_ret_instance(ri);
+		utask->depth--;
+	}
+	utask->return_instances = ri;
+}
+
+static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs)
+{
+	struct return_instance *ri;
+	struct uprobe_task *utask;
+	unsigned long orig_ret_vaddr, trampoline_vaddr;
+	bool chained;
+
+	if (!get_xol_area())
+		return;
+
+	utask = get_utask();
+	if (!utask)
+		return;
+
+	if (utask->depth >= MAX_URETPROBE_DEPTH) {
+		printk_ratelimited(KERN_INFO "uprobe: omit uretprobe due to"
+				" nestedness limit pid/tgid=%d/%d\n",
+				current->pid, current->tgid);
+		return;
+	}
+
+	ri = kmalloc(sizeof(struct return_instance), GFP_KERNEL);
+	if (!ri)
+		return;
+
+	trampoline_vaddr = get_trampoline_vaddr();
+	orig_ret_vaddr = arch_uretprobe_hijack_return_addr(trampoline_vaddr, regs);
+	if (orig_ret_vaddr == -1)
+		goto fail;
+
+	/* drop the entries invalidated by longjmp() */
+	chained = (orig_ret_vaddr == trampoline_vaddr);
+	cleanup_return_instances(utask, chained, regs);
+
+	/*
+	 * We don't want to keep trampoline address in stack, rather keep the
+	 * original return address of first caller thru all the consequent
+	 * instances. This also makes breakpoint unwrapping easier.
+	 */
+	if (chained) {
+		if (!utask->return_instances) {
+			/*
+			 * This situation is not possible. Likely we have an
+			 * attack from user-space.
+			 */
+			uprobe_warn(current, "handle tail call");
+			goto fail;
+		}
+		orig_ret_vaddr = utask->return_instances->orig_ret_vaddr;
+	}
+
+	ri->uprobe = get_uprobe(uprobe);
+	ri->func = instruction_pointer(regs);
+	ri->stack = user_stack_pointer(regs);
+	ri->orig_ret_vaddr = orig_ret_vaddr;
+	ri->chained = chained;
+
+	utask->depth++;
+	ri->next = utask->return_instances;
+	utask->return_instances = ri;
+
+	return;
+ fail:
+	kfree(ri);
+}
+
+/* Prepare to single-step probed instruction out of line. */
+static int
+pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr)
+{
+	struct uprobe_task *utask;
+	unsigned long xol_vaddr;
+	int err;
+
+	utask = get_utask();
+	if (!utask)
+		return -ENOMEM;
+
+	xol_vaddr = xol_get_insn_slot(uprobe);
+	if (!xol_vaddr)
+		return -ENOMEM;
+
+	utask->xol_vaddr = xol_vaddr;
+	utask->vaddr = bp_vaddr;
+
+	err = arch_uprobe_pre_xol(&uprobe->arch, regs);
+	if (unlikely(err)) {
+		xol_free_insn_slot(current);
+		return err;
+	}
+
+	utask->active_uprobe = uprobe;
+	utask->state = UTASK_SSTEP;
+	return 0;
+}
+
+/*
+ * If we are singlestepping, then ensure this thread is not connected to
+ * non-fatal signals until completion of singlestep.  When xol insn itself
+ * triggers the signal,  restart the original insn even if the task is
+ * already SIGKILL'ed (since coredump should report the correct ip).  This
+ * is even more important if the task has a handler for SIGSEGV/etc, The
+ * _same_ instruction should be repeated again after return from the signal
+ * handler, and SSTEP can never finish in this case.
+ */
+bool uprobe_deny_signal(void)
+{
+	struct task_struct *t = current;
+	struct uprobe_task *utask = t->utask;
+
+	if (likely(!utask || !utask->active_uprobe))
+		return false;
+
+	WARN_ON_ONCE(utask->state != UTASK_SSTEP);
+
+	if (task_sigpending(t)) {
+		spin_lock_irq(&t->sighand->siglock);
+		clear_tsk_thread_flag(t, TIF_SIGPENDING);
+		spin_unlock_irq(&t->sighand->siglock);
+
+		if (__fatal_signal_pending(t) || arch_uprobe_xol_was_trapped(t)) {
+			utask->state = UTASK_SSTEP_TRAPPED;
+			set_tsk_thread_flag(t, TIF_UPROBE);
+		}
+	}
+
+	return true;
+}
+
+static void mmf_recalc_uprobes(struct mm_struct *mm)
+{
+	VMA_ITERATOR(vmi, mm, 0);
+	struct vm_area_struct *vma;
+
+	for_each_vma(vmi, vma) {
+		if (!valid_vma(vma, false))
+			continue;
+		/*
+		 * This is not strictly accurate, we can race with
+		 * uprobe_unregister() and see the already removed
+		 * uprobe if delete_uprobe() was not yet called.
+		 * Or this uprobe can be filtered out.
+		 */
+		if (vma_has_uprobes(vma, vma->vm_start, vma->vm_end))
+			return;
+	}
+
+	clear_bit(MMF_HAS_UPROBES, &mm->flags);
+}
+
+static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr)
+{
+	struct page *page;
+	uprobe_opcode_t opcode;
+	int result;
+
+	if (WARN_ON_ONCE(!IS_ALIGNED(vaddr, UPROBE_SWBP_INSN_SIZE)))
+		return -EINVAL;
+
+	pagefault_disable();
+	result = __get_user(opcode, (uprobe_opcode_t __user *)vaddr);
+	pagefault_enable();
+
+	if (likely(result == 0))
+		goto out;
+
+	/*
+	 * The NULL 'tsk' here ensures that any faults that occur here
+	 * will not be accounted to the task.  'mm' *is* current->mm,
+	 * but we treat this as a 'remote' access since it is
+	 * essentially a kernel access to the memory.
+	 */
+	result = get_user_pages_remote(mm, vaddr, 1, FOLL_FORCE, &page,
+			NULL, NULL);
+	if (result < 0)
+		return result;
+
+	copy_from_page(page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
+	put_page(page);
+ out:
+	/* This needs to return true for any variant of the trap insn */
+	return is_trap_insn(&opcode);
+}
+
+static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
+{
+	struct mm_struct *mm = current->mm;
+	struct uprobe *uprobe = NULL;
+	struct vm_area_struct *vma;
+
+	mmap_read_lock(mm);
+	vma = vma_lookup(mm, bp_vaddr);
+	if (vma) {
+		if (valid_vma(vma, false)) {
+			struct inode *inode = file_inode(vma->vm_file);
+			loff_t offset = vaddr_to_offset(vma, bp_vaddr);
+
+			uprobe = find_uprobe(inode, offset);
+		}
+
+		if (!uprobe)
+			*is_swbp = is_trap_at_addr(mm, bp_vaddr);
+	} else {
+		*is_swbp = -EFAULT;
+	}
+
+	if (!uprobe && test_and_clear_bit(MMF_RECALC_UPROBES, &mm->flags))
+		mmf_recalc_uprobes(mm);
+	mmap_read_unlock(mm);
+
+	return uprobe;
+}
+
+static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
+{
+	struct uprobe_consumer *uc;
+	int remove = UPROBE_HANDLER_REMOVE;
+	bool need_prep = false; /* prepare return uprobe, when needed */
+
+	down_read(&uprobe->register_rwsem);
+	for (uc = uprobe->consumers; uc; uc = uc->next) {
+		int rc = 0;
+
+		if (uc->handler) {
+			rc = uc->handler(uc, regs);
+			WARN(rc & ~UPROBE_HANDLER_MASK,
+				"bad rc=0x%x from %ps()\n", rc, uc->handler);
+		}
+
+		if (uc->ret_handler)
+			need_prep = true;
+
+		remove &= rc;
+	}
+
+	if (need_prep && !remove)
+		prepare_uretprobe(uprobe, regs); /* put bp at return */
+
+	if (remove && uprobe->consumers) {
+		WARN_ON(!uprobe_is_active(uprobe));
+		unapply_uprobe(uprobe, current->mm);
+	}
+	up_read(&uprobe->register_rwsem);
+}
+
+static void
+handle_uretprobe_chain(struct return_instance *ri, struct pt_regs *regs)
+{
+	struct uprobe *uprobe = ri->uprobe;
+	struct uprobe_consumer *uc;
+
+	down_read(&uprobe->register_rwsem);
+	for (uc = uprobe->consumers; uc; uc = uc->next) {
+		if (uc->ret_handler)
+			uc->ret_handler(uc, ri->func, regs);
+	}
+	up_read(&uprobe->register_rwsem);
+}
+
+static struct return_instance *find_next_ret_chain(struct return_instance *ri)
+{
+	bool chained;
+
+	do {
+		chained = ri->chained;
+		ri = ri->next;	/* can't be NULL if chained */
+	} while (chained);
+
+	return ri;
+}
+
+static void handle_trampoline(struct pt_regs *regs)
+{
+	struct uprobe_task *utask;
+	struct return_instance *ri, *next;
+	bool valid;
+
+	utask = current->utask;
+	if (!utask)
+		goto sigill;
+
+	ri = utask->return_instances;
+	if (!ri)
+		goto sigill;
+
+	do {
+		/*
+		 * We should throw out the frames invalidated by longjmp().
+		 * If this chain is valid, then the next one should be alive
+		 * or NULL; the latter case means that nobody but ri->func
+		 * could hit this trampoline on return. TODO: sigaltstack().
+		 */
+		next = find_next_ret_chain(ri);
+		valid = !next || arch_uretprobe_is_alive(next, RP_CHECK_RET, regs);
+
+		instruction_pointer_set(regs, ri->orig_ret_vaddr);
+		do {
+			if (valid)
+				handle_uretprobe_chain(ri, regs);
+			ri = free_ret_instance(ri);
+			utask->depth--;
+		} while (ri != next);
+	} while (!valid);
+
+	utask->return_instances = ri;
+	return;
+
+ sigill:
+	uprobe_warn(current, "handle uretprobe, sending SIGILL.");
+	force_sig(SIGILL);
+
+}
+
+bool __weak arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs)
+{
+	return false;
+}
+
+bool __weak arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
+					struct pt_regs *regs)
+{
+	return true;
+}
+
+/*
+ * Run handler and ask thread to singlestep.
+ * Ensure all non-fatal signals cannot interrupt thread while it singlesteps.
+ */
+static void handle_swbp(struct pt_regs *regs)
+{
+	struct uprobe *uprobe;
+	unsigned long bp_vaddr;
+	int is_swbp;
+
+	bp_vaddr = uprobe_get_swbp_addr(regs);
+	if (bp_vaddr == get_trampoline_vaddr())
+		return handle_trampoline(regs);
+
+	uprobe = find_active_uprobe(bp_vaddr, &is_swbp);
+	if (!uprobe) {
+		if (is_swbp > 0) {
+			/* No matching uprobe; signal SIGTRAP. */
+			force_sig(SIGTRAP);
+		} else {
+			/*
+			 * Either we raced with uprobe_unregister() or we can't
+			 * access this memory. The latter is only possible if
+			 * another thread plays with our ->mm. In both cases
+			 * we can simply restart. If this vma was unmapped we
+			 * can pretend this insn was not executed yet and get
+			 * the (correct) SIGSEGV after restart.
+			 */
+			instruction_pointer_set(regs, bp_vaddr);
+		}
+		return;
+	}
+
+	/* change it in advance for ->handler() and restart */
+	instruction_pointer_set(regs, bp_vaddr);
+
+	/*
+	 * TODO: move copy_insn/etc into _register and remove this hack.
+	 * After we hit the bp, _unregister + _register can install the
+	 * new and not-yet-analyzed uprobe at the same address, restart.
+	 */
+	if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags)))
+		goto out;
+
+	/*
+	 * Pairs with the smp_wmb() in prepare_uprobe().
+	 *
+	 * Guarantees that if we see the UPROBE_COPY_INSN bit set, then
+	 * we must also see the stores to &uprobe->arch performed by the
+	 * prepare_uprobe() call.
+	 */
+	smp_rmb();
+
+	/* Tracing handlers use ->utask to communicate with fetch methods */
+	if (!get_utask())
+		goto out;
+
+	if (arch_uprobe_ignore(&uprobe->arch, regs))
+		goto out;
+
+	handler_chain(uprobe, regs);
+
+	if (arch_uprobe_skip_sstep(&uprobe->arch, regs))
+		goto out;
+
+	if (!pre_ssout(uprobe, regs, bp_vaddr))
+		return;
+
+	/* arch_uprobe_skip_sstep() succeeded, or restart if can't singlestep */
+out:
+	put_uprobe(uprobe);
+}
+
+/*
+ * Perform required fix-ups and disable singlestep.
+ * Allow pending signals to take effect.
+ */
+static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs)
+{
+	struct uprobe *uprobe;
+	int err = 0;
+
+	uprobe = utask->active_uprobe;
+	if (utask->state == UTASK_SSTEP_ACK)
+		err = arch_uprobe_post_xol(&uprobe->arch, regs);
+	else if (utask->state == UTASK_SSTEP_TRAPPED)
+		arch_uprobe_abort_xol(&uprobe->arch, regs);
+	else
+		WARN_ON_ONCE(1);
+
+	put_uprobe(uprobe);
+	utask->active_uprobe = NULL;
+	utask->state = UTASK_RUNNING;
+	xol_free_insn_slot(current);
+
+	spin_lock_irq(&current->sighand->siglock);
+	recalc_sigpending(); /* see uprobe_deny_signal() */
+	spin_unlock_irq(&current->sighand->siglock);
+
+	if (unlikely(err)) {
+		uprobe_warn(current, "execute the probed insn, sending SIGILL.");
+		force_sig(SIGILL);
+	}
+}
+
+/*
+ * On breakpoint hit, breakpoint notifier sets the TIF_UPROBE flag and
+ * allows the thread to return from interrupt. After that handle_swbp()
+ * sets utask->active_uprobe.
+ *
+ * On singlestep exception, singlestep notifier sets the TIF_UPROBE flag
+ * and allows the thread to return from interrupt.
+ *
+ * While returning to userspace, thread notices the TIF_UPROBE flag and calls
+ * uprobe_notify_resume().
+ */
+void uprobe_notify_resume(struct pt_regs *regs)
+{
+	struct uprobe_task *utask;
+
+	clear_thread_flag(TIF_UPROBE);
+
+	utask = current->utask;
+	if (utask && utask->active_uprobe)
+		handle_singlestep(utask, regs);
+	else
+		handle_swbp(regs);
+}
+
+/*
+ * uprobe_pre_sstep_notifier gets called from interrupt context as part of
+ * notifier mechanism. Set TIF_UPROBE flag and indicate breakpoint hit.
+ */
+int uprobe_pre_sstep_notifier(struct pt_regs *regs)
+{
+	if (!current->mm)
+		return 0;
+
+	if (!test_bit(MMF_HAS_UPROBES, &current->mm->flags) &&
+	    (!current->utask || !current->utask->return_instances))
+		return 0;
+
+	set_thread_flag(TIF_UPROBE);
+	return 1;
+}
+
+/*
+ * uprobe_post_sstep_notifier gets called in interrupt context as part of notifier
+ * mechanism. Set TIF_UPROBE flag and indicate completion of singlestep.
+ */
+int uprobe_post_sstep_notifier(struct pt_regs *regs)
+{
+	struct uprobe_task *utask = current->utask;
+
+	if (!current->mm || !utask || !utask->active_uprobe)
+		/* task is currently not uprobed */
+		return 0;
+
+	utask->state = UTASK_SSTEP_ACK;
+	set_thread_flag(TIF_UPROBE);
+	return 1;
+}
+
+static struct notifier_block uprobe_exception_nb = {
+	.notifier_call		= arch_uprobe_exception_notify,
+	.priority		= INT_MAX-1,	/* notified after kprobes, kgdb */
+};
+
+void __init uprobes_init(void)
+{
+	int i;
+
+	for (i = 0; i < UPROBES_HASH_SZ; i++)
+		mutex_init(&uprobes_mmap_mutex[i]);
+
+	BUG_ON(register_die_notifier(&uprobe_exception_nb));
+}
diff --git a/kernel/exec_domain.c b/kernel/exec_domain.c
new file mode 100644
index 000000000..33f07c5f2
--- /dev/null
+++ b/kernel/exec_domain.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Handling of different ABIs (personalities).
+ *
+ * We group personalities into execution domains which have their
+ * own handlers for kernel entry points, signal mapping, etc...
+ *
+ * 2001-05-06	Complete rewrite,  Christoph Hellwig (hch@infradead.org)
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/module.h>
+#include <linux/personality.h>
+#include <linux/proc_fs.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/syscalls.h>
+#include <linux/sysctl.h>
+#include <linux/types.h>
+
+#ifdef CONFIG_PROC_FS
+static int execdomains_proc_show(struct seq_file *m, void *v)
+{
+	seq_puts(m, "0-0\tLinux           \t[kernel]\n");
+	return 0;
+}
+
+static int __init proc_execdomains_init(void)
+{
+	proc_create_single("execdomains", 0, NULL, execdomains_proc_show);
+	return 0;
+}
+module_init(proc_execdomains_init);
+#endif
+
+SYSCALL_DEFINE1(personality, unsigned int, personality)
+{
+	unsigned int old = current->personality;
+
+	if (personality != 0xffffffff)
+		set_personality(personality);
+
+	return old;
+}
diff --git a/kernel/exit.c b/kernel/exit.c
new file mode 100644
index 000000000..bccfa4218
--- /dev/null
+++ b/kernel/exit.c
@@ -0,0 +1,1915 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/kernel/exit.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/sched/autogroup.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/stat.h>
+#include <linux/sched/task.h>
+#include <linux/sched/task_stack.h>
+#include <linux/sched/cputime.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/capability.h>
+#include <linux/completion.h>
+#include <linux/personality.h>
+#include <linux/tty.h>
+#include <linux/iocontext.h>
+#include <linux/key.h>
+#include <linux/cpu.h>
+#include <linux/acct.h>
+#include <linux/tsacct_kern.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/freezer.h>
+#include <linux/binfmts.h>
+#include <linux/nsproxy.h>
+#include <linux/pid_namespace.h>
+#include <linux/ptrace.h>
+#include <linux/profile.h>
+#include <linux/mount.h>
+#include <linux/proc_fs.h>
+#include <linux/kthread.h>
+#include <linux/mempolicy.h>
+#include <linux/taskstats_kern.h>
+#include <linux/delayacct.h>
+#include <linux/cgroup.h>
+#include <linux/syscalls.h>
+#include <linux/signal.h>
+#include <linux/posix-timers.h>
+#include <linux/cn_proc.h>
+#include <linux/mutex.h>
+#include <linux/futex.h>
+#include <linux/pipe_fs_i.h>
+#include <linux/audit.h> /* for audit_free() */
+#include <linux/resource.h>
+#include <linux/task_io_accounting_ops.h>
+#include <linux/blkdev.h>
+#include <linux/task_work.h>
+#include <linux/fs_struct.h>
+#include <linux/init_task.h>
+#include <linux/perf_event.h>
+#include <trace/events/sched.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/oom.h>
+#include <linux/writeback.h>
+#include <linux/shm.h>
+#include <linux/kcov.h>
+#include <linux/kmsan.h>
+#include <linux/random.h>
+#include <linux/rcuwait.h>
+#include <linux/compat.h>
+#include <linux/io_uring.h>
+#include <linux/kprobes.h>
+#include <linux/rethook.h>
+#include <linux/sysfs.h>
+
+#include <linux/uaccess.h>
+#include <asm/unistd.h>
+#include <asm/mmu_context.h>
+
+/*
+ * The default value should be high enough to not crash a system that randomly
+ * crashes its kernel from time to time, but low enough to at least not permit
+ * overflowing 32-bit refcounts or the ldsem writer count.
+ */
+static unsigned int oops_limit = 10000;
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table kern_exit_table[] = {
+	{
+		.procname       = "oops_limit",
+		.data           = &oops_limit,
+		.maxlen         = sizeof(oops_limit),
+		.mode           = 0644,
+		.proc_handler   = proc_douintvec,
+	},
+	{ }
+};
+
+static __init int kernel_exit_sysctls_init(void)
+{
+	register_sysctl_init("kernel", kern_exit_table);
+	return 0;
+}
+late_initcall(kernel_exit_sysctls_init);
+#endif
+
+static atomic_t oops_count = ATOMIC_INIT(0);
+
+#ifdef CONFIG_SYSFS
+static ssize_t oops_count_show(struct kobject *kobj, struct kobj_attribute *attr,
+			       char *page)
+{
+	return sysfs_emit(page, "%d\n", atomic_read(&oops_count));
+}
+
+static struct kobj_attribute oops_count_attr = __ATTR_RO(oops_count);
+
+static __init int kernel_exit_sysfs_init(void)
+{
+	sysfs_add_file_to_group(kernel_kobj, &oops_count_attr.attr, NULL);
+	return 0;
+}
+late_initcall(kernel_exit_sysfs_init);
+#endif
+
+static void __unhash_process(struct task_struct *p, bool group_dead)
+{
+	nr_threads--;
+	detach_pid(p, PIDTYPE_PID);
+	if (group_dead) {
+		detach_pid(p, PIDTYPE_TGID);
+		detach_pid(p, PIDTYPE_PGID);
+		detach_pid(p, PIDTYPE_SID);
+
+		list_del_rcu(&p->tasks);
+		list_del_init(&p->sibling);
+		__this_cpu_dec(process_counts);
+	}
+	list_del_rcu(&p->thread_group);
+	list_del_rcu(&p->thread_node);
+}
+
+/*
+ * This function expects the tasklist_lock write-locked.
+ */
+static void __exit_signal(struct task_struct *tsk)
+{
+	struct signal_struct *sig = tsk->signal;
+	bool group_dead = thread_group_leader(tsk);
+	struct sighand_struct *sighand;
+	struct tty_struct *tty;
+	u64 utime, stime;
+
+	sighand = rcu_dereference_check(tsk->sighand,
+					lockdep_tasklist_lock_is_held());
+	spin_lock(&sighand->siglock);
+
+#ifdef CONFIG_POSIX_TIMERS
+	posix_cpu_timers_exit(tsk);
+	if (group_dead)
+		posix_cpu_timers_exit_group(tsk);
+#endif
+
+	if (group_dead) {
+		tty = sig->tty;
+		sig->tty = NULL;
+	} else {
+		/*
+		 * If there is any task waiting for the group exit
+		 * then notify it:
+		 */
+		if (sig->notify_count > 0 && !--sig->notify_count)
+			wake_up_process(sig->group_exec_task);
+
+		if (tsk == sig->curr_target)
+			sig->curr_target = next_thread(tsk);
+	}
+
+	add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
+			      sizeof(unsigned long long));
+
+	/*
+	 * Accumulate here the counters for all threads as they die. We could
+	 * skip the group leader because it is the last user of signal_struct,
+	 * but we want to avoid the race with thread_group_cputime() which can
+	 * see the empty ->thread_head list.
+	 */
+	task_cputime(tsk, &utime, &stime);
+	write_seqlock(&sig->stats_lock);
+	sig->utime += utime;
+	sig->stime += stime;
+	sig->gtime += task_gtime(tsk);
+	sig->min_flt += tsk->min_flt;
+	sig->maj_flt += tsk->maj_flt;
+	sig->nvcsw += tsk->nvcsw;
+	sig->nivcsw += tsk->nivcsw;
+	sig->inblock += task_io_get_inblock(tsk);
+	sig->oublock += task_io_get_oublock(tsk);
+	task_io_accounting_add(&sig->ioac, &tsk->ioac);
+	sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
+	sig->nr_threads--;
+	__unhash_process(tsk, group_dead);
+	write_sequnlock(&sig->stats_lock);
+
+	/*
+	 * Do this under ->siglock, we can race with another thread
+	 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
+	 */
+	flush_sigqueue(&tsk->pending);
+	tsk->sighand = NULL;
+	spin_unlock(&sighand->siglock);
+
+	__cleanup_sighand(sighand);
+	clear_tsk_thread_flag(tsk, TIF_SIGPENDING);
+	if (group_dead) {
+		flush_sigqueue(&sig->shared_pending);
+		tty_kref_put(tty);
+	}
+}
+
+static void delayed_put_task_struct(struct rcu_head *rhp)
+{
+	struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
+
+	kprobe_flush_task(tsk);
+	rethook_flush_task(tsk);
+	perf_event_delayed_put(tsk);
+	trace_sched_process_free(tsk);
+	put_task_struct(tsk);
+}
+
+void put_task_struct_rcu_user(struct task_struct *task)
+{
+	if (refcount_dec_and_test(&task->rcu_users))
+		call_rcu(&task->rcu, delayed_put_task_struct);
+}
+
+void __weak release_thread(struct task_struct *dead_task)
+{
+}
+
+void release_task(struct task_struct *p)
+{
+	struct task_struct *leader;
+	struct pid *thread_pid;
+	int zap_leader;
+repeat:
+	/* don't need to get the RCU readlock here - the process is dead and
+	 * can't be modifying its own credentials. But shut RCU-lockdep up */
+	rcu_read_lock();
+	dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
+	rcu_read_unlock();
+
+	cgroup_release(p);
+
+	write_lock_irq(&tasklist_lock);
+	ptrace_release_task(p);
+	thread_pid = get_pid(p->thread_pid);
+	__exit_signal(p);
+
+	/*
+	 * If we are the last non-leader member of the thread
+	 * group, and the leader is zombie, then notify the
+	 * group leader's parent process. (if it wants notification.)
+	 */
+	zap_leader = 0;
+	leader = p->group_leader;
+	if (leader != p && thread_group_empty(leader)
+			&& leader->exit_state == EXIT_ZOMBIE) {
+		/*
+		 * If we were the last child thread and the leader has
+		 * exited already, and the leader's parent ignores SIGCHLD,
+		 * then we are the one who should release the leader.
+		 */
+		zap_leader = do_notify_parent(leader, leader->exit_signal);
+		if (zap_leader)
+			leader->exit_state = EXIT_DEAD;
+	}
+
+	write_unlock_irq(&tasklist_lock);
+	seccomp_filter_release(p);
+	proc_flush_pid(thread_pid);
+	put_pid(thread_pid);
+	release_thread(p);
+	put_task_struct_rcu_user(p);
+
+	p = leader;
+	if (unlikely(zap_leader))
+		goto repeat;
+}
+
+int rcuwait_wake_up(struct rcuwait *w)
+{
+	int ret = 0;
+	struct task_struct *task;
+
+	rcu_read_lock();
+
+	/*
+	 * Order condition vs @task, such that everything prior to the load
+	 * of @task is visible. This is the condition as to why the user called
+	 * rcuwait_wake() in the first place. Pairs with set_current_state()
+	 * barrier (A) in rcuwait_wait_event().
+	 *
+	 *    WAIT                WAKE
+	 *    [S] tsk = current	  [S] cond = true
+	 *        MB (A)	      MB (B)
+	 *    [L] cond		  [L] tsk
+	 */
+	smp_mb(); /* (B) */
+
+	task = rcu_dereference(w->task);
+	if (task)
+		ret = wake_up_process(task);
+	rcu_read_unlock();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rcuwait_wake_up);
+
+/*
+ * Determine if a process group is "orphaned", according to the POSIX
+ * definition in 2.2.2.52.  Orphaned process groups are not to be affected
+ * by terminal-generated stop signals.  Newly orphaned process groups are
+ * to receive a SIGHUP and a SIGCONT.
+ *
+ * "I ask you, have you ever known what it is to be an orphan?"
+ */
+static int will_become_orphaned_pgrp(struct pid *pgrp,
+					struct task_struct *ignored_task)
+{
+	struct task_struct *p;
+
+	do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+		if ((p == ignored_task) ||
+		    (p->exit_state && thread_group_empty(p)) ||
+		    is_global_init(p->real_parent))
+			continue;
+
+		if (task_pgrp(p->real_parent) != pgrp &&
+		    task_session(p->real_parent) == task_session(p))
+			return 0;
+	} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+
+	return 1;
+}
+
+int is_current_pgrp_orphaned(void)
+{
+	int retval;
+
+	read_lock(&tasklist_lock);
+	retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
+	read_unlock(&tasklist_lock);
+
+	return retval;
+}
+
+static bool has_stopped_jobs(struct pid *pgrp)
+{
+	struct task_struct *p;
+
+	do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+		if (p->signal->flags & SIGNAL_STOP_STOPPED)
+			return true;
+	} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+
+	return false;
+}
+
+/*
+ * Check to see if any process groups have become orphaned as
+ * a result of our exiting, and if they have any stopped jobs,
+ * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
+ */
+static void
+kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
+{
+	struct pid *pgrp = task_pgrp(tsk);
+	struct task_struct *ignored_task = tsk;
+
+	if (!parent)
+		/* exit: our father is in a different pgrp than
+		 * we are and we were the only connection outside.
+		 */
+		parent = tsk->real_parent;
+	else
+		/* reparent: our child is in a different pgrp than
+		 * we are, and it was the only connection outside.
+		 */
+		ignored_task = NULL;
+
+	if (task_pgrp(parent) != pgrp &&
+	    task_session(parent) == task_session(tsk) &&
+	    will_become_orphaned_pgrp(pgrp, ignored_task) &&
+	    has_stopped_jobs(pgrp)) {
+		__kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
+		__kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
+	}
+}
+
+static void coredump_task_exit(struct task_struct *tsk)
+{
+	struct core_state *core_state;
+
+	/*
+	 * Serialize with any possible pending coredump.
+	 * We must hold siglock around checking core_state
+	 * and setting PF_POSTCOREDUMP.  The core-inducing thread
+	 * will increment ->nr_threads for each thread in the
+	 * group without PF_POSTCOREDUMP set.
+	 */
+	spin_lock_irq(&tsk->sighand->siglock);
+	tsk->flags |= PF_POSTCOREDUMP;
+	core_state = tsk->signal->core_state;
+	spin_unlock_irq(&tsk->sighand->siglock);
+	if (core_state) {
+		struct core_thread self;
+
+		self.task = current;
+		if (self.task->flags & PF_SIGNALED)
+			self.next = xchg(&core_state->dumper.next, &self);
+		else
+			self.task = NULL;
+		/*
+		 * Implies mb(), the result of xchg() must be visible
+		 * to core_state->dumper.
+		 */
+		if (atomic_dec_and_test(&core_state->nr_threads))
+			complete(&core_state->startup);
+
+		for (;;) {
+			set_current_state(TASK_UNINTERRUPTIBLE|TASK_FREEZABLE);
+			if (!self.task) /* see coredump_finish() */
+				break;
+			schedule();
+		}
+		__set_current_state(TASK_RUNNING);
+	}
+}
+
+#ifdef CONFIG_MEMCG
+/*
+ * A task is exiting.   If it owned this mm, find a new owner for the mm.
+ */
+void mm_update_next_owner(struct mm_struct *mm)
+{
+	struct task_struct *c, *g, *p = current;
+
+retry:
+	/*
+	 * If the exiting or execing task is not the owner, it's
+	 * someone else's problem.
+	 */
+	if (mm->owner != p)
+		return;
+	/*
+	 * The current owner is exiting/execing and there are no other
+	 * candidates.  Do not leave the mm pointing to a possibly
+	 * freed task structure.
+	 */
+	if (atomic_read(&mm->mm_users) <= 1) {
+		WRITE_ONCE(mm->owner, NULL);
+		return;
+	}
+
+	read_lock(&tasklist_lock);
+	/*
+	 * Search in the children
+	 */
+	list_for_each_entry(c, &p->children, sibling) {
+		if (c->mm == mm)
+			goto assign_new_owner;
+	}
+
+	/*
+	 * Search in the siblings
+	 */
+	list_for_each_entry(c, &p->real_parent->children, sibling) {
+		if (c->mm == mm)
+			goto assign_new_owner;
+	}
+
+	/*
+	 * Search through everything else, we should not get here often.
+	 */
+	for_each_process(g) {
+		if (g->flags & PF_KTHREAD)
+			continue;
+		for_each_thread(g, c) {
+			if (c->mm == mm)
+				goto assign_new_owner;
+			if (c->mm)
+				break;
+		}
+	}
+	read_unlock(&tasklist_lock);
+	/*
+	 * We found no owner yet mm_users > 1: this implies that we are
+	 * most likely racing with swapoff (try_to_unuse()) or /proc or
+	 * ptrace or page migration (get_task_mm()).  Mark owner as NULL.
+	 */
+	WRITE_ONCE(mm->owner, NULL);
+	return;
+
+assign_new_owner:
+	BUG_ON(c == p);
+	get_task_struct(c);
+	/*
+	 * The task_lock protects c->mm from changing.
+	 * We always want mm->owner->mm == mm
+	 */
+	task_lock(c);
+	/*
+	 * Delay read_unlock() till we have the task_lock()
+	 * to ensure that c does not slip away underneath us
+	 */
+	read_unlock(&tasklist_lock);
+	if (c->mm != mm) {
+		task_unlock(c);
+		put_task_struct(c);
+		goto retry;
+	}
+	WRITE_ONCE(mm->owner, c);
+	lru_gen_migrate_mm(mm);
+	task_unlock(c);
+	put_task_struct(c);
+}
+#endif /* CONFIG_MEMCG */
+
+/*
+ * Turn us into a lazy TLB process if we
+ * aren't already..
+ */
+static void exit_mm(void)
+{
+	struct mm_struct *mm = current->mm;
+
+	exit_mm_release(current, mm);
+	if (!mm)
+		return;
+	sync_mm_rss(mm);
+	mmap_read_lock(mm);
+	mmgrab(mm);
+	BUG_ON(mm != current->active_mm);
+	/* more a memory barrier than a real lock */
+	task_lock(current);
+	/*
+	 * When a thread stops operating on an address space, the loop
+	 * in membarrier_private_expedited() may not observe that
+	 * tsk->mm, and the loop in membarrier_global_expedited() may
+	 * not observe a MEMBARRIER_STATE_GLOBAL_EXPEDITED
+	 * rq->membarrier_state, so those would not issue an IPI.
+	 * Membarrier requires a memory barrier after accessing
+	 * user-space memory, before clearing tsk->mm or the
+	 * rq->membarrier_state.
+	 */
+	smp_mb__after_spinlock();
+	local_irq_disable();
+	current->mm = NULL;
+	membarrier_update_current_mm(NULL);
+	enter_lazy_tlb(mm, current);
+	local_irq_enable();
+	task_unlock(current);
+	mmap_read_unlock(mm);
+	mm_update_next_owner(mm);
+	mmput(mm);
+	if (test_thread_flag(TIF_MEMDIE))
+		exit_oom_victim();
+}
+
+static struct task_struct *find_alive_thread(struct task_struct *p)
+{
+	struct task_struct *t;
+
+	for_each_thread(p, t) {
+		if (!(t->flags & PF_EXITING))
+			return t;
+	}
+	return NULL;
+}
+
+static struct task_struct *find_child_reaper(struct task_struct *father,
+						struct list_head *dead)
+	__releases(&tasklist_lock)
+	__acquires(&tasklist_lock)
+{
+	struct pid_namespace *pid_ns = task_active_pid_ns(father);
+	struct task_struct *reaper = pid_ns->child_reaper;
+	struct task_struct *p, *n;
+
+	if (likely(reaper != father))
+		return reaper;
+
+	reaper = find_alive_thread(father);
+	if (reaper) {
+		pid_ns->child_reaper = reaper;
+		return reaper;
+	}
+
+	write_unlock_irq(&tasklist_lock);
+
+	list_for_each_entry_safe(p, n, dead, ptrace_entry) {
+		list_del_init(&p->ptrace_entry);
+		release_task(p);
+	}
+
+	zap_pid_ns_processes(pid_ns);
+	write_lock_irq(&tasklist_lock);
+
+	return father;
+}
+
+/*
+ * When we die, we re-parent all our children, and try to:
+ * 1. give them to another thread in our thread group, if such a member exists
+ * 2. give it to the first ancestor process which prctl'd itself as a
+ *    child_subreaper for its children (like a service manager)
+ * 3. give it to the init process (PID 1) in our pid namespace
+ */
+static struct task_struct *find_new_reaper(struct task_struct *father,
+					   struct task_struct *child_reaper)
+{
+	struct task_struct *thread, *reaper;
+
+	thread = find_alive_thread(father);
+	if (thread)
+		return thread;
+
+	if (father->signal->has_child_subreaper) {
+		unsigned int ns_level = task_pid(father)->level;
+		/*
+		 * Find the first ->is_child_subreaper ancestor in our pid_ns.
+		 * We can't check reaper != child_reaper to ensure we do not
+		 * cross the namespaces, the exiting parent could be injected
+		 * by setns() + fork().
+		 * We check pid->level, this is slightly more efficient than
+		 * task_active_pid_ns(reaper) != task_active_pid_ns(father).
+		 */
+		for (reaper = father->real_parent;
+		     task_pid(reaper)->level == ns_level;
+		     reaper = reaper->real_parent) {
+			if (reaper == &init_task)
+				break;
+			if (!reaper->signal->is_child_subreaper)
+				continue;
+			thread = find_alive_thread(reaper);
+			if (thread)
+				return thread;
+		}
+	}
+
+	return child_reaper;
+}
+
+/*
+* Any that need to be release_task'd are put on the @dead list.
+ */
+static void reparent_leader(struct task_struct *father, struct task_struct *p,
+				struct list_head *dead)
+{
+	if (unlikely(p->exit_state == EXIT_DEAD))
+		return;
+
+	/* We don't want people slaying init. */
+	p->exit_signal = SIGCHLD;
+
+	/* If it has exited notify the new parent about this child's death. */
+	if (!p->ptrace &&
+	    p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {
+		if (do_notify_parent(p, p->exit_signal)) {
+			p->exit_state = EXIT_DEAD;
+			list_add(&p->ptrace_entry, dead);
+		}
+	}
+
+	kill_orphaned_pgrp(p, father);
+}
+
+/*
+ * This does two things:
+ *
+ * A.  Make init inherit all the child processes
+ * B.  Check to see if any process groups have become orphaned
+ *	as a result of our exiting, and if they have any stopped
+ *	jobs, send them a SIGHUP and then a SIGCONT.  (POSIX 3.2.2.2)
+ */
+static void forget_original_parent(struct task_struct *father,
+					struct list_head *dead)
+{
+	struct task_struct *p, *t, *reaper;
+
+	if (unlikely(!list_empty(&father->ptraced)))
+		exit_ptrace(father, dead);
+
+	/* Can drop and reacquire tasklist_lock */
+	reaper = find_child_reaper(father, dead);
+	if (list_empty(&father->children))
+		return;
+
+	reaper = find_new_reaper(father, reaper);
+	list_for_each_entry(p, &father->children, sibling) {
+		for_each_thread(p, t) {
+			RCU_INIT_POINTER(t->real_parent, reaper);
+			BUG_ON((!t->ptrace) != (rcu_access_pointer(t->parent) == father));
+			if (likely(!t->ptrace))
+				t->parent = t->real_parent;
+			if (t->pdeath_signal)
+				group_send_sig_info(t->pdeath_signal,
+						    SEND_SIG_NOINFO, t,
+						    PIDTYPE_TGID);
+		}
+		/*
+		 * If this is a threaded reparent there is no need to
+		 * notify anyone anything has happened.
+		 */
+		if (!same_thread_group(reaper, father))
+			reparent_leader(father, p, dead);
+	}
+	list_splice_tail_init(&father->children, &reaper->children);
+}
+
+/*
+ * Send signals to all our closest relatives so that they know
+ * to properly mourn us..
+ */
+static void exit_notify(struct task_struct *tsk, int group_dead)
+{
+	bool autoreap;
+	struct task_struct *p, *n;
+	LIST_HEAD(dead);
+
+	write_lock_irq(&tasklist_lock);
+	forget_original_parent(tsk, &dead);
+
+	if (group_dead)
+		kill_orphaned_pgrp(tsk->group_leader, NULL);
+
+	tsk->exit_state = EXIT_ZOMBIE;
+	if (unlikely(tsk->ptrace)) {
+		int sig = thread_group_leader(tsk) &&
+				thread_group_empty(tsk) &&
+				!ptrace_reparented(tsk) ?
+			tsk->exit_signal : SIGCHLD;
+		autoreap = do_notify_parent(tsk, sig);
+	} else if (thread_group_leader(tsk)) {
+		autoreap = thread_group_empty(tsk) &&
+			do_notify_parent(tsk, tsk->exit_signal);
+	} else {
+		autoreap = true;
+	}
+
+	if (autoreap) {
+		tsk->exit_state = EXIT_DEAD;
+		list_add(&tsk->ptrace_entry, &dead);
+	}
+
+	/* mt-exec, de_thread() is waiting for group leader */
+	if (unlikely(tsk->signal->notify_count < 0))
+		wake_up_process(tsk->signal->group_exec_task);
+	write_unlock_irq(&tasklist_lock);
+
+	list_for_each_entry_safe(p, n, &dead, ptrace_entry) {
+		list_del_init(&p->ptrace_entry);
+		release_task(p);
+	}
+}
+
+#ifdef CONFIG_DEBUG_STACK_USAGE
+static void check_stack_usage(void)
+{
+	static DEFINE_SPINLOCK(low_water_lock);
+	static int lowest_to_date = THREAD_SIZE;
+	unsigned long free;
+
+	free = stack_not_used(current);
+
+	if (free >= lowest_to_date)
+		return;
+
+	spin_lock(&low_water_lock);
+	if (free < lowest_to_date) {
+		pr_info("%s (%d) used greatest stack depth: %lu bytes left\n",
+			current->comm, task_pid_nr(current), free);
+		lowest_to_date = free;
+	}
+	spin_unlock(&low_water_lock);
+}
+#else
+static inline void check_stack_usage(void) {}
+#endif
+
+static void synchronize_group_exit(struct task_struct *tsk, long code)
+{
+	struct sighand_struct *sighand = tsk->sighand;
+	struct signal_struct *signal = tsk->signal;
+
+	spin_lock_irq(&sighand->siglock);
+	signal->quick_threads--;
+	if ((signal->quick_threads == 0) &&
+	    !(signal->flags & SIGNAL_GROUP_EXIT)) {
+		signal->flags = SIGNAL_GROUP_EXIT;
+		signal->group_exit_code = code;
+		signal->group_stop_count = 0;
+	}
+	spin_unlock_irq(&sighand->siglock);
+}
+
+void __noreturn do_exit(long code)
+{
+	struct task_struct *tsk = current;
+	int group_dead;
+
+	WARN_ON(irqs_disabled());
+
+	synchronize_group_exit(tsk, code);
+
+	WARN_ON(tsk->plug);
+
+	kcov_task_exit(tsk);
+	kmsan_task_exit(tsk);
+
+	coredump_task_exit(tsk);
+	ptrace_event(PTRACE_EVENT_EXIT, code);
+
+	validate_creds_for_do_exit(tsk);
+
+	io_uring_files_cancel();
+	exit_signals(tsk);  /* sets PF_EXITING */
+
+	/* sync mm's RSS info before statistics gathering */
+	if (tsk->mm)
+		sync_mm_rss(tsk->mm);
+	acct_update_integrals(tsk);
+	group_dead = atomic_dec_and_test(&tsk->signal->live);
+	if (group_dead) {
+		/*
+		 * If the last thread of global init has exited, panic
+		 * immediately to get a useable coredump.
+		 */
+		if (unlikely(is_global_init(tsk)))
+			panic("Attempted to kill init! exitcode=0x%08x\n",
+				tsk->signal->group_exit_code ?: (int)code);
+
+#ifdef CONFIG_POSIX_TIMERS
+		hrtimer_cancel(&tsk->signal->real_timer);
+		exit_itimers(tsk);
+#endif
+		if (tsk->mm)
+			setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm);
+	}
+	acct_collect(code, group_dead);
+	if (group_dead)
+		tty_audit_exit();
+	audit_free(tsk);
+
+	tsk->exit_code = code;
+	taskstats_exit(tsk, group_dead);
+
+	exit_mm();
+
+	if (group_dead)
+		acct_process();
+	trace_sched_process_exit(tsk);
+
+	exit_sem(tsk);
+	exit_shm(tsk);
+	exit_files(tsk);
+	exit_fs(tsk);
+	if (group_dead)
+		disassociate_ctty(1);
+	exit_task_namespaces(tsk);
+	exit_task_work(tsk);
+	exit_thread(tsk);
+
+	/*
+	 * Flush inherited counters to the parent - before the parent
+	 * gets woken up by child-exit notifications.
+	 *
+	 * because of cgroup mode, must be called before cgroup_exit()
+	 */
+	perf_event_exit_task(tsk);
+
+	sched_autogroup_exit_task(tsk);
+	cgroup_exit(tsk);
+
+	/*
+	 * FIXME: do that only when needed, using sched_exit tracepoint
+	 */
+	flush_ptrace_hw_breakpoint(tsk);
+
+	exit_tasks_rcu_start();
+	exit_notify(tsk, group_dead);
+	proc_exit_connector(tsk);
+	mpol_put_task_policy(tsk);
+#ifdef CONFIG_FUTEX
+	if (unlikely(current->pi_state_cache))
+		kfree(current->pi_state_cache);
+#endif
+	/*
+	 * Make sure we are holding no locks:
+	 */
+	debug_check_no_locks_held();
+
+	if (tsk->io_context)
+		exit_io_context(tsk);
+
+	if (tsk->splice_pipe)
+		free_pipe_info(tsk->splice_pipe);
+
+	if (tsk->task_frag.page)
+		put_page(tsk->task_frag.page);
+
+	validate_creds_for_do_exit(tsk);
+	exit_task_stack_account(tsk);
+
+	check_stack_usage();
+	preempt_disable();
+	if (tsk->nr_dirtied)
+		__this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied);
+	exit_rcu();
+	exit_tasks_rcu_finish();
+
+	lockdep_free_task(tsk);
+	do_task_dead();
+}
+
+void __noreturn make_task_dead(int signr)
+{
+	/*
+	 * Take the task off the cpu after something catastrophic has
+	 * happened.
+	 *
+	 * We can get here from a kernel oops, sometimes with preemption off.
+	 * Start by checking for critical errors.
+	 * Then fix up important state like USER_DS and preemption.
+	 * Then do everything else.
+	 */
+	struct task_struct *tsk = current;
+	unsigned int limit;
+
+	if (unlikely(in_interrupt()))
+		panic("Aiee, killing interrupt handler!");
+	if (unlikely(!tsk->pid))
+		panic("Attempted to kill the idle task!");
+
+	if (unlikely(irqs_disabled())) {
+		pr_info("note: %s[%d] exited with irqs disabled\n",
+			current->comm, task_pid_nr(current));
+		local_irq_enable();
+	}
+	if (unlikely(in_atomic())) {
+		pr_info("note: %s[%d] exited with preempt_count %d\n",
+			current->comm, task_pid_nr(current),
+			preempt_count());
+		preempt_count_set(PREEMPT_ENABLED);
+	}
+
+	/*
+	 * Every time the system oopses, if the oops happens while a reference
+	 * to an object was held, the reference leaks.
+	 * If the oops doesn't also leak memory, repeated oopsing can cause
+	 * reference counters to wrap around (if they're not using refcount_t).
+	 * This means that repeated oopsing can make unexploitable-looking bugs
+	 * exploitable through repeated oopsing.
+	 * To make sure this can't happen, place an upper bound on how often the
+	 * kernel may oops without panic().
+	 */
+	limit = READ_ONCE(oops_limit);
+	if (atomic_inc_return(&oops_count) >= limit && limit)
+		panic("Oopsed too often (kernel.oops_limit is %d)", limit);
+
+	/*
+	 * We're taking recursive faults here in make_task_dead. Safest is to just
+	 * leave this task alone and wait for reboot.
+	 */
+	if (unlikely(tsk->flags & PF_EXITING)) {
+		pr_alert("Fixing recursive fault but reboot is needed!\n");
+		futex_exit_recursive(tsk);
+		tsk->exit_state = EXIT_DEAD;
+		refcount_inc(&tsk->rcu_users);
+		do_task_dead();
+	}
+
+	do_exit(signr);
+}
+
+SYSCALL_DEFINE1(exit, int, error_code)
+{
+	do_exit((error_code&0xff)<<8);
+}
+
+/*
+ * Take down every thread in the group.  This is called by fatal signals
+ * as well as by sys_exit_group (below).
+ */
+void __noreturn
+do_group_exit(int exit_code)
+{
+	struct signal_struct *sig = current->signal;
+
+	if (sig->flags & SIGNAL_GROUP_EXIT)
+		exit_code = sig->group_exit_code;
+	else if (sig->group_exec_task)
+		exit_code = 0;
+	else {
+		struct sighand_struct *const sighand = current->sighand;
+
+		spin_lock_irq(&sighand->siglock);
+		if (sig->flags & SIGNAL_GROUP_EXIT)
+			/* Another thread got here before we took the lock.  */
+			exit_code = sig->group_exit_code;
+		else if (sig->group_exec_task)
+			exit_code = 0;
+		else {
+			sig->group_exit_code = exit_code;
+			sig->flags = SIGNAL_GROUP_EXIT;
+			zap_other_threads(current);
+		}
+		spin_unlock_irq(&sighand->siglock);
+	}
+
+	do_exit(exit_code);
+	/* NOTREACHED */
+}
+
+/*
+ * this kills every thread in the thread group. Note that any externally
+ * wait4()-ing process will get the correct exit code - even if this
+ * thread is not the thread group leader.
+ */
+SYSCALL_DEFINE1(exit_group, int, error_code)
+{
+	do_group_exit((error_code & 0xff) << 8);
+	/* NOTREACHED */
+	return 0;
+}
+
+struct waitid_info {
+	pid_t pid;
+	uid_t uid;
+	int status;
+	int cause;
+};
+
+struct wait_opts {
+	enum pid_type		wo_type;
+	int			wo_flags;
+	struct pid		*wo_pid;
+
+	struct waitid_info	*wo_info;
+	int			wo_stat;
+	struct rusage		*wo_rusage;
+
+	wait_queue_entry_t		child_wait;
+	int			notask_error;
+};
+
+static int eligible_pid(struct wait_opts *wo, struct task_struct *p)
+{
+	return	wo->wo_type == PIDTYPE_MAX ||
+		task_pid_type(p, wo->wo_type) == wo->wo_pid;
+}
+
+static int
+eligible_child(struct wait_opts *wo, bool ptrace, struct task_struct *p)
+{
+	if (!eligible_pid(wo, p))
+		return 0;
+
+	/*
+	 * Wait for all children (clone and not) if __WALL is set or
+	 * if it is traced by us.
+	 */
+	if (ptrace || (wo->wo_flags & __WALL))
+		return 1;
+
+	/*
+	 * Otherwise, wait for clone children *only* if __WCLONE is set;
+	 * otherwise, wait for non-clone children *only*.
+	 *
+	 * Note: a "clone" child here is one that reports to its parent
+	 * using a signal other than SIGCHLD, or a non-leader thread which
+	 * we can only see if it is traced by us.
+	 */
+	if ((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE))
+		return 0;
+
+	return 1;
+}
+
+/*
+ * Handle sys_wait4 work for one task in state EXIT_ZOMBIE.  We hold
+ * read_lock(&tasklist_lock) on entry.  If we return zero, we still hold
+ * the lock and this task is uninteresting.  If we return nonzero, we have
+ * released the lock and the system call should return.
+ */
+static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
+{
+	int state, status;
+	pid_t pid = task_pid_vnr(p);
+	uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p));
+	struct waitid_info *infop;
+
+	if (!likely(wo->wo_flags & WEXITED))
+		return 0;
+
+	if (unlikely(wo->wo_flags & WNOWAIT)) {
+		status = (p->signal->flags & SIGNAL_GROUP_EXIT)
+			? p->signal->group_exit_code : p->exit_code;
+		get_task_struct(p);
+		read_unlock(&tasklist_lock);
+		sched_annotate_sleep();
+		if (wo->wo_rusage)
+			getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
+		put_task_struct(p);
+		goto out_info;
+	}
+	/*
+	 * Move the task's state to DEAD/TRACE, only one thread can do this.
+	 */
+	state = (ptrace_reparented(p) && thread_group_leader(p)) ?
+		EXIT_TRACE : EXIT_DEAD;
+	if (cmpxchg(&p->exit_state, EXIT_ZOMBIE, state) != EXIT_ZOMBIE)
+		return 0;
+	/*
+	 * We own this thread, nobody else can reap it.
+	 */
+	read_unlock(&tasklist_lock);
+	sched_annotate_sleep();
+
+	/*
+	 * Check thread_group_leader() to exclude the traced sub-threads.
+	 */
+	if (state == EXIT_DEAD && thread_group_leader(p)) {
+		struct signal_struct *sig = p->signal;
+		struct signal_struct *psig = current->signal;
+		unsigned long maxrss;
+		u64 tgutime, tgstime;
+
+		/*
+		 * The resource counters for the group leader are in its
+		 * own task_struct.  Those for dead threads in the group
+		 * are in its signal_struct, as are those for the child
+		 * processes it has previously reaped.  All these
+		 * accumulate in the parent's signal_struct c* fields.
+		 *
+		 * We don't bother to take a lock here to protect these
+		 * p->signal fields because the whole thread group is dead
+		 * and nobody can change them.
+		 *
+		 * psig->stats_lock also protects us from our sub-threads
+		 * which can reap other children at the same time. Until
+		 * we change k_getrusage()-like users to rely on this lock
+		 * we have to take ->siglock as well.
+		 *
+		 * We use thread_group_cputime_adjusted() to get times for
+		 * the thread group, which consolidates times for all threads
+		 * in the group including the group leader.
+		 */
+		thread_group_cputime_adjusted(p, &tgutime, &tgstime);
+		spin_lock_irq(&current->sighand->siglock);
+		write_seqlock(&psig->stats_lock);
+		psig->cutime += tgutime + sig->cutime;
+		psig->cstime += tgstime + sig->cstime;
+		psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime;
+		psig->cmin_flt +=
+			p->min_flt + sig->min_flt + sig->cmin_flt;
+		psig->cmaj_flt +=
+			p->maj_flt + sig->maj_flt + sig->cmaj_flt;
+		psig->cnvcsw +=
+			p->nvcsw + sig->nvcsw + sig->cnvcsw;
+		psig->cnivcsw +=
+			p->nivcsw + sig->nivcsw + sig->cnivcsw;
+		psig->cinblock +=
+			task_io_get_inblock(p) +
+			sig->inblock + sig->cinblock;
+		psig->coublock +=
+			task_io_get_oublock(p) +
+			sig->oublock + sig->coublock;
+		maxrss = max(sig->maxrss, sig->cmaxrss);
+		if (psig->cmaxrss < maxrss)
+			psig->cmaxrss = maxrss;
+		task_io_accounting_add(&psig->ioac, &p->ioac);
+		task_io_accounting_add(&psig->ioac, &sig->ioac);
+		write_sequnlock(&psig->stats_lock);
+		spin_unlock_irq(&current->sighand->siglock);
+	}
+
+	if (wo->wo_rusage)
+		getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
+	status = (p->signal->flags & SIGNAL_GROUP_EXIT)
+		? p->signal->group_exit_code : p->exit_code;
+	wo->wo_stat = status;
+
+	if (state == EXIT_TRACE) {
+		write_lock_irq(&tasklist_lock);
+		/* We dropped tasklist, ptracer could die and untrace */
+		ptrace_unlink(p);
+
+		/* If parent wants a zombie, don't release it now */
+		state = EXIT_ZOMBIE;
+		if (do_notify_parent(p, p->exit_signal))
+			state = EXIT_DEAD;
+		p->exit_state = state;
+		write_unlock_irq(&tasklist_lock);
+	}
+	if (state == EXIT_DEAD)
+		release_task(p);
+
+out_info:
+	infop = wo->wo_info;
+	if (infop) {
+		if ((status & 0x7f) == 0) {
+			infop->cause = CLD_EXITED;
+			infop->status = status >> 8;
+		} else {
+			infop->cause = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
+			infop->status = status & 0x7f;
+		}
+		infop->pid = pid;
+		infop->uid = uid;
+	}
+
+	return pid;
+}
+
+static int *task_stopped_code(struct task_struct *p, bool ptrace)
+{
+	if (ptrace) {
+		if (task_is_traced(p) && !(p->jobctl & JOBCTL_LISTENING))
+			return &p->exit_code;
+	} else {
+		if (p->signal->flags & SIGNAL_STOP_STOPPED)
+			return &p->signal->group_exit_code;
+	}
+	return NULL;
+}
+
+/**
+ * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
+ * @wo: wait options
+ * @ptrace: is the wait for ptrace
+ * @p: task to wait for
+ *
+ * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
+ *
+ * CONTEXT:
+ * read_lock(&tasklist_lock), which is released if return value is
+ * non-zero.  Also, grabs and releases @p->sighand->siglock.
+ *
+ * RETURNS:
+ * 0 if wait condition didn't exist and search for other wait conditions
+ * should continue.  Non-zero return, -errno on failure and @p's pid on
+ * success, implies that tasklist_lock is released and wait condition
+ * search should terminate.
+ */
+static int wait_task_stopped(struct wait_opts *wo,
+				int ptrace, struct task_struct *p)
+{
+	struct waitid_info *infop;
+	int exit_code, *p_code, why;
+	uid_t uid = 0; /* unneeded, required by compiler */
+	pid_t pid;
+
+	/*
+	 * Traditionally we see ptrace'd stopped tasks regardless of options.
+	 */
+	if (!ptrace && !(wo->wo_flags & WUNTRACED))
+		return 0;
+
+	if (!task_stopped_code(p, ptrace))
+		return 0;
+
+	exit_code = 0;
+	spin_lock_irq(&p->sighand->siglock);
+
+	p_code = task_stopped_code(p, ptrace);
+	if (unlikely(!p_code))
+		goto unlock_sig;
+
+	exit_code = *p_code;
+	if (!exit_code)
+		goto unlock_sig;
+
+	if (!unlikely(wo->wo_flags & WNOWAIT))
+		*p_code = 0;
+
+	uid = from_kuid_munged(current_user_ns(), task_uid(p));
+unlock_sig:
+	spin_unlock_irq(&p->sighand->siglock);
+	if (!exit_code)
+		return 0;
+
+	/*
+	 * Now we are pretty sure this task is interesting.
+	 * Make sure it doesn't get reaped out from under us while we
+	 * give up the lock and then examine it below.  We don't want to
+	 * keep holding onto the tasklist_lock while we call getrusage and
+	 * possibly take page faults for user memory.
+	 */
+	get_task_struct(p);
+	pid = task_pid_vnr(p);
+	why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
+	read_unlock(&tasklist_lock);
+	sched_annotate_sleep();
+	if (wo->wo_rusage)
+		getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
+	put_task_struct(p);
+
+	if (likely(!(wo->wo_flags & WNOWAIT)))
+		wo->wo_stat = (exit_code << 8) | 0x7f;
+
+	infop = wo->wo_info;
+	if (infop) {
+		infop->cause = why;
+		infop->status = exit_code;
+		infop->pid = pid;
+		infop->uid = uid;
+	}
+	return pid;
+}
+
+/*
+ * Handle do_wait work for one task in a live, non-stopped state.
+ * read_lock(&tasklist_lock) on entry.  If we return zero, we still hold
+ * the lock and this task is uninteresting.  If we return nonzero, we have
+ * released the lock and the system call should return.
+ */
+static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
+{
+	struct waitid_info *infop;
+	pid_t pid;
+	uid_t uid;
+
+	if (!unlikely(wo->wo_flags & WCONTINUED))
+		return 0;
+
+	if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
+		return 0;
+
+	spin_lock_irq(&p->sighand->siglock);
+	/* Re-check with the lock held.  */
+	if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
+		spin_unlock_irq(&p->sighand->siglock);
+		return 0;
+	}
+	if (!unlikely(wo->wo_flags & WNOWAIT))
+		p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
+	uid = from_kuid_munged(current_user_ns(), task_uid(p));
+	spin_unlock_irq(&p->sighand->siglock);
+
+	pid = task_pid_vnr(p);
+	get_task_struct(p);
+	read_unlock(&tasklist_lock);
+	sched_annotate_sleep();
+	if (wo->wo_rusage)
+		getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
+	put_task_struct(p);
+
+	infop = wo->wo_info;
+	if (!infop) {
+		wo->wo_stat = 0xffff;
+	} else {
+		infop->cause = CLD_CONTINUED;
+		infop->pid = pid;
+		infop->uid = uid;
+		infop->status = SIGCONT;
+	}
+	return pid;
+}
+
+/*
+ * Consider @p for a wait by @parent.
+ *
+ * -ECHILD should be in ->notask_error before the first call.
+ * Returns nonzero for a final return, when we have unlocked tasklist_lock.
+ * Returns zero if the search for a child should continue;
+ * then ->notask_error is 0 if @p is an eligible child,
+ * or still -ECHILD.
+ */
+static int wait_consider_task(struct wait_opts *wo, int ptrace,
+				struct task_struct *p)
+{
+	/*
+	 * We can race with wait_task_zombie() from another thread.
+	 * Ensure that EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE transition
+	 * can't confuse the checks below.
+	 */
+	int exit_state = READ_ONCE(p->exit_state);
+	int ret;
+
+	if (unlikely(exit_state == EXIT_DEAD))
+		return 0;
+
+	ret = eligible_child(wo, ptrace, p);
+	if (!ret)
+		return ret;
+
+	if (unlikely(exit_state == EXIT_TRACE)) {
+		/*
+		 * ptrace == 0 means we are the natural parent. In this case
+		 * we should clear notask_error, debugger will notify us.
+		 */
+		if (likely(!ptrace))
+			wo->notask_error = 0;
+		return 0;
+	}
+
+	if (likely(!ptrace) && unlikely(p->ptrace)) {
+		/*
+		 * If it is traced by its real parent's group, just pretend
+		 * the caller is ptrace_do_wait() and reap this child if it
+		 * is zombie.
+		 *
+		 * This also hides group stop state from real parent; otherwise
+		 * a single stop can be reported twice as group and ptrace stop.
+		 * If a ptracer wants to distinguish these two events for its
+		 * own children it should create a separate process which takes
+		 * the role of real parent.
+		 */
+		if (!ptrace_reparented(p))
+			ptrace = 1;
+	}
+
+	/* slay zombie? */
+	if (exit_state == EXIT_ZOMBIE) {
+		/* we don't reap group leaders with subthreads */
+		if (!delay_group_leader(p)) {
+			/*
+			 * A zombie ptracee is only visible to its ptracer.
+			 * Notification and reaping will be cascaded to the
+			 * real parent when the ptracer detaches.
+			 */
+			if (unlikely(ptrace) || likely(!p->ptrace))
+				return wait_task_zombie(wo, p);
+		}
+
+		/*
+		 * Allow access to stopped/continued state via zombie by
+		 * falling through.  Clearing of notask_error is complex.
+		 *
+		 * When !@ptrace:
+		 *
+		 * If WEXITED is set, notask_error should naturally be
+		 * cleared.  If not, subset of WSTOPPED|WCONTINUED is set,
+		 * so, if there are live subthreads, there are events to
+		 * wait for.  If all subthreads are dead, it's still safe
+		 * to clear - this function will be called again in finite
+		 * amount time once all the subthreads are released and
+		 * will then return without clearing.
+		 *
+		 * When @ptrace:
+		 *
+		 * Stopped state is per-task and thus can't change once the
+		 * target task dies.  Only continued and exited can happen.
+		 * Clear notask_error if WCONTINUED | WEXITED.
+		 */
+		if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED)))
+			wo->notask_error = 0;
+	} else {
+		/*
+		 * @p is alive and it's gonna stop, continue or exit, so
+		 * there always is something to wait for.
+		 */
+		wo->notask_error = 0;
+	}
+
+	/*
+	 * Wait for stopped.  Depending on @ptrace, different stopped state
+	 * is used and the two don't interact with each other.
+	 */
+	ret = wait_task_stopped(wo, ptrace, p);
+	if (ret)
+		return ret;
+
+	/*
+	 * Wait for continued.  There's only one continued state and the
+	 * ptracer can consume it which can confuse the real parent.  Don't
+	 * use WCONTINUED from ptracer.  You don't need or want it.
+	 */
+	return wait_task_continued(wo, p);
+}
+
+/*
+ * Do the work of do_wait() for one thread in the group, @tsk.
+ *
+ * -ECHILD should be in ->notask_error before the first call.
+ * Returns nonzero for a final return, when we have unlocked tasklist_lock.
+ * Returns zero if the search for a child should continue; then
+ * ->notask_error is 0 if there were any eligible children,
+ * or still -ECHILD.
+ */
+static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk)
+{
+	struct task_struct *p;
+
+	list_for_each_entry(p, &tsk->children, sibling) {
+		int ret = wait_consider_task(wo, 0, p);
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk)
+{
+	struct task_struct *p;
+
+	list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {
+		int ret = wait_consider_task(wo, 1, p);
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int child_wait_callback(wait_queue_entry_t *wait, unsigned mode,
+				int sync, void *key)
+{
+	struct wait_opts *wo = container_of(wait, struct wait_opts,
+						child_wait);
+	struct task_struct *p = key;
+
+	if (!eligible_pid(wo, p))
+		return 0;
+
+	if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent)
+		return 0;
+
+	return default_wake_function(wait, mode, sync, key);
+}
+
+void __wake_up_parent(struct task_struct *p, struct task_struct *parent)
+{
+	__wake_up_sync_key(&parent->signal->wait_chldexit,
+			   TASK_INTERRUPTIBLE, p);
+}
+
+static bool is_effectively_child(struct wait_opts *wo, bool ptrace,
+				 struct task_struct *target)
+{
+	struct task_struct *parent =
+		!ptrace ? target->real_parent : target->parent;
+
+	return current == parent || (!(wo->wo_flags & __WNOTHREAD) &&
+				     same_thread_group(current, parent));
+}
+
+/*
+ * Optimization for waiting on PIDTYPE_PID. No need to iterate through child
+ * and tracee lists to find the target task.
+ */
+static int do_wait_pid(struct wait_opts *wo)
+{
+	bool ptrace;
+	struct task_struct *target;
+	int retval;
+
+	ptrace = false;
+	target = pid_task(wo->wo_pid, PIDTYPE_TGID);
+	if (target && is_effectively_child(wo, ptrace, target)) {
+		retval = wait_consider_task(wo, ptrace, target);
+		if (retval)
+			return retval;
+	}
+
+	ptrace = true;
+	target = pid_task(wo->wo_pid, PIDTYPE_PID);
+	if (target && target->ptrace &&
+	    is_effectively_child(wo, ptrace, target)) {
+		retval = wait_consider_task(wo, ptrace, target);
+		if (retval)
+			return retval;
+	}
+
+	return 0;
+}
+
+static long do_wait(struct wait_opts *wo)
+{
+	int retval;
+
+	trace_sched_process_wait(wo->wo_pid);
+
+	init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);
+	wo->child_wait.private = current;
+	add_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);
+repeat:
+	/*
+	 * If there is nothing that can match our criteria, just get out.
+	 * We will clear ->notask_error to zero if we see any child that
+	 * might later match our criteria, even if we are not able to reap
+	 * it yet.
+	 */
+	wo->notask_error = -ECHILD;
+	if ((wo->wo_type < PIDTYPE_MAX) &&
+	   (!wo->wo_pid || !pid_has_task(wo->wo_pid, wo->wo_type)))
+		goto notask;
+
+	set_current_state(TASK_INTERRUPTIBLE);
+	read_lock(&tasklist_lock);
+
+	if (wo->wo_type == PIDTYPE_PID) {
+		retval = do_wait_pid(wo);
+		if (retval)
+			goto end;
+	} else {
+		struct task_struct *tsk = current;
+
+		do {
+			retval = do_wait_thread(wo, tsk);
+			if (retval)
+				goto end;
+
+			retval = ptrace_do_wait(wo, tsk);
+			if (retval)
+				goto end;
+
+			if (wo->wo_flags & __WNOTHREAD)
+				break;
+		} while_each_thread(current, tsk);
+	}
+	read_unlock(&tasklist_lock);
+
+notask:
+	retval = wo->notask_error;
+	if (!retval && !(wo->wo_flags & WNOHANG)) {
+		retval = -ERESTARTSYS;
+		if (!signal_pending(current)) {
+			schedule();
+			goto repeat;
+		}
+	}
+end:
+	__set_current_state(TASK_RUNNING);
+	remove_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);
+	return retval;
+}
+
+static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop,
+			  int options, struct rusage *ru)
+{
+	struct wait_opts wo;
+	struct pid *pid = NULL;
+	enum pid_type type;
+	long ret;
+	unsigned int f_flags = 0;
+
+	if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED|
+			__WNOTHREAD|__WCLONE|__WALL))
+		return -EINVAL;
+	if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
+		return -EINVAL;
+
+	switch (which) {
+	case P_ALL:
+		type = PIDTYPE_MAX;
+		break;
+	case P_PID:
+		type = PIDTYPE_PID;
+		if (upid <= 0)
+			return -EINVAL;
+
+		pid = find_get_pid(upid);
+		break;
+	case P_PGID:
+		type = PIDTYPE_PGID;
+		if (upid < 0)
+			return -EINVAL;
+
+		if (upid)
+			pid = find_get_pid(upid);
+		else
+			pid = get_task_pid(current, PIDTYPE_PGID);
+		break;
+	case P_PIDFD:
+		type = PIDTYPE_PID;
+		if (upid < 0)
+			return -EINVAL;
+
+		pid = pidfd_get_pid(upid, &f_flags);
+		if (IS_ERR(pid))
+			return PTR_ERR(pid);
+
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	wo.wo_type	= type;
+	wo.wo_pid	= pid;
+	wo.wo_flags	= options;
+	wo.wo_info	= infop;
+	wo.wo_rusage	= ru;
+	if (f_flags & O_NONBLOCK)
+		wo.wo_flags |= WNOHANG;
+
+	ret = do_wait(&wo);
+	if (!ret && !(options & WNOHANG) && (f_flags & O_NONBLOCK))
+		ret = -EAGAIN;
+
+	put_pid(pid);
+	return ret;
+}
+
+SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
+		infop, int, options, struct rusage __user *, ru)
+{
+	struct rusage r;
+	struct waitid_info info = {.status = 0};
+	long err = kernel_waitid(which, upid, &info, options, ru ? &r : NULL);
+	int signo = 0;
+
+	if (err > 0) {
+		signo = SIGCHLD;
+		err = 0;
+		if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
+			return -EFAULT;
+	}
+	if (!infop)
+		return err;
+
+	if (!user_write_access_begin(infop, sizeof(*infop)))
+		return -EFAULT;
+
+	unsafe_put_user(signo, &infop->si_signo, Efault);
+	unsafe_put_user(0, &infop->si_errno, Efault);
+	unsafe_put_user(info.cause, &infop->si_code, Efault);
+	unsafe_put_user(info.pid, &infop->si_pid, Efault);
+	unsafe_put_user(info.uid, &infop->si_uid, Efault);
+	unsafe_put_user(info.status, &infop->si_status, Efault);
+	user_write_access_end();
+	return err;
+Efault:
+	user_write_access_end();
+	return -EFAULT;
+}
+
+long kernel_wait4(pid_t upid, int __user *stat_addr, int options,
+		  struct rusage *ru)
+{
+	struct wait_opts wo;
+	struct pid *pid = NULL;
+	enum pid_type type;
+	long ret;
+
+	if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
+			__WNOTHREAD|__WCLONE|__WALL))
+		return -EINVAL;
+
+	/* -INT_MIN is not defined */
+	if (upid == INT_MIN)
+		return -ESRCH;
+
+	if (upid == -1)
+		type = PIDTYPE_MAX;
+	else if (upid < 0) {
+		type = PIDTYPE_PGID;
+		pid = find_get_pid(-upid);
+	} else if (upid == 0) {
+		type = PIDTYPE_PGID;
+		pid = get_task_pid(current, PIDTYPE_PGID);
+	} else /* upid > 0 */ {
+		type = PIDTYPE_PID;
+		pid = find_get_pid(upid);
+	}
+
+	wo.wo_type	= type;
+	wo.wo_pid	= pid;
+	wo.wo_flags	= options | WEXITED;
+	wo.wo_info	= NULL;
+	wo.wo_stat	= 0;
+	wo.wo_rusage	= ru;
+	ret = do_wait(&wo);
+	put_pid(pid);
+	if (ret > 0 && stat_addr && put_user(wo.wo_stat, stat_addr))
+		ret = -EFAULT;
+
+	return ret;
+}
+
+int kernel_wait(pid_t pid, int *stat)
+{
+	struct wait_opts wo = {
+		.wo_type	= PIDTYPE_PID,
+		.wo_pid		= find_get_pid(pid),
+		.wo_flags	= WEXITED,
+	};
+	int ret;
+
+	ret = do_wait(&wo);
+	if (ret > 0 && wo.wo_stat)
+		*stat = wo.wo_stat;
+	put_pid(wo.wo_pid);
+	return ret;
+}
+
+SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
+		int, options, struct rusage __user *, ru)
+{
+	struct rusage r;
+	long err = kernel_wait4(upid, stat_addr, options, ru ? &r : NULL);
+
+	if (err > 0) {
+		if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
+			return -EFAULT;
+	}
+	return err;
+}
+
+#ifdef __ARCH_WANT_SYS_WAITPID
+
+/*
+ * sys_waitpid() remains for compatibility. waitpid() should be
+ * implemented by calling sys_wait4() from libc.a.
+ */
+SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)
+{
+	return kernel_wait4(pid, stat_addr, options, NULL);
+}
+
+#endif
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE4(wait4,
+	compat_pid_t, pid,
+	compat_uint_t __user *, stat_addr,
+	int, options,
+	struct compat_rusage __user *, ru)
+{
+	struct rusage r;
+	long err = kernel_wait4(pid, stat_addr, options, ru ? &r : NULL);
+	if (err > 0) {
+		if (ru && put_compat_rusage(&r, ru))
+			return -EFAULT;
+	}
+	return err;
+}
+
+COMPAT_SYSCALL_DEFINE5(waitid,
+		int, which, compat_pid_t, pid,
+		struct compat_siginfo __user *, infop, int, options,
+		struct compat_rusage __user *, uru)
+{
+	struct rusage ru;
+	struct waitid_info info = {.status = 0};
+	long err = kernel_waitid(which, pid, &info, options, uru ? &ru : NULL);
+	int signo = 0;
+	if (err > 0) {
+		signo = SIGCHLD;
+		err = 0;
+		if (uru) {
+			/* kernel_waitid() overwrites everything in ru */
+			if (COMPAT_USE_64BIT_TIME)
+				err = copy_to_user(uru, &ru, sizeof(ru));
+			else
+				err = put_compat_rusage(&ru, uru);
+			if (err)
+				return -EFAULT;
+		}
+	}
+
+	if (!infop)
+		return err;
+
+	if (!user_write_access_begin(infop, sizeof(*infop)))
+		return -EFAULT;
+
+	unsafe_put_user(signo, &infop->si_signo, Efault);
+	unsafe_put_user(0, &infop->si_errno, Efault);
+	unsafe_put_user(info.cause, &infop->si_code, Efault);
+	unsafe_put_user(info.pid, &infop->si_pid, Efault);
+	unsafe_put_user(info.uid, &infop->si_uid, Efault);
+	unsafe_put_user(info.status, &infop->si_status, Efault);
+	user_write_access_end();
+	return err;
+Efault:
+	user_write_access_end();
+	return -EFAULT;
+}
+#endif
+
+/**
+ * thread_group_exited - check that a thread group has exited
+ * @pid: tgid of thread group to be checked.
+ *
+ * Test if the thread group represented by tgid has exited (all
+ * threads are zombies, dead or completely gone).
+ *
+ * Return: true if the thread group has exited. false otherwise.
+ */
+bool thread_group_exited(struct pid *pid)
+{
+	struct task_struct *task;
+	bool exited;
+
+	rcu_read_lock();
+	task = pid_task(pid, PIDTYPE_PID);
+	exited = !task ||
+		(READ_ONCE(task->exit_state) && thread_group_empty(task));
+	rcu_read_unlock();
+
+	return exited;
+}
+EXPORT_SYMBOL(thread_group_exited);
+
+__weak void abort(void)
+{
+	BUG();
+
+	/* if that doesn't kill us, halt */
+	panic("Oops failed to kill thread");
+}
+EXPORT_SYMBOL(abort);
diff --git a/kernel/extable.c b/kernel/extable.c
new file mode 100644
index 000000000..71f482581
--- /dev/null
+++ b/kernel/extable.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Rewritten by Rusty Russell, on the backs of many others...
+   Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM.
+
+*/
+#include <linux/elf.h>
+#include <linux/ftrace.h>
+#include <linux/memory.h>
+#include <linux/extable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/init.h>
+#include <linux/kprobes.h>
+#include <linux/filter.h>
+
+#include <asm/sections.h>
+#include <linux/uaccess.h>
+
+/*
+ * mutex protecting text section modification (dynamic code patching).
+ * some users need to sleep (allocating memory...) while they hold this lock.
+ *
+ * Note: Also protects SMP-alternatives modification on x86.
+ *
+ * NOT exported to modules - patching kernel text is a really delicate matter.
+ */
+DEFINE_MUTEX(text_mutex);
+
+extern struct exception_table_entry __start___ex_table[];
+extern struct exception_table_entry __stop___ex_table[];
+
+/* Cleared by build time tools if the table is already sorted. */
+u32 __initdata __visible main_extable_sort_needed = 1;
+
+/* Sort the kernel's built-in exception table */
+void __init sort_main_extable(void)
+{
+	if (main_extable_sort_needed &&
+	    &__stop___ex_table > &__start___ex_table) {
+		pr_notice("Sorting __ex_table...\n");
+		sort_extable(__start___ex_table, __stop___ex_table);
+	}
+}
+
+/* Given an address, look for it in the kernel exception table */
+const
+struct exception_table_entry *search_kernel_exception_table(unsigned long addr)
+{
+	return search_extable(__start___ex_table,
+			      __stop___ex_table - __start___ex_table, addr);
+}
+
+/* Given an address, look for it in the exception tables. */
+const struct exception_table_entry *search_exception_tables(unsigned long addr)
+{
+	const struct exception_table_entry *e;
+
+	e = search_kernel_exception_table(addr);
+	if (!e)
+		e = search_module_extables(addr);
+	if (!e)
+		e = search_bpf_extables(addr);
+	return e;
+}
+
+int notrace core_kernel_text(unsigned long addr)
+{
+	if (is_kernel_text(addr))
+		return 1;
+
+	if (system_state < SYSTEM_FREEING_INITMEM &&
+	    is_kernel_inittext(addr))
+		return 1;
+	return 0;
+}
+
+int __kernel_text_address(unsigned long addr)
+{
+	if (kernel_text_address(addr))
+		return 1;
+	/*
+	 * There might be init symbols in saved stacktraces.
+	 * Give those symbols a chance to be printed in
+	 * backtraces (such as lockdep traces).
+	 *
+	 * Since we are after the module-symbols check, there's
+	 * no danger of address overlap:
+	 */
+	if (is_kernel_inittext(addr))
+		return 1;
+	return 0;
+}
+
+int kernel_text_address(unsigned long addr)
+{
+	bool no_rcu;
+	int ret = 1;
+
+	if (core_kernel_text(addr))
+		return 1;
+
+	/*
+	 * If a stack dump happens while RCU is not watching, then
+	 * RCU needs to be notified that it requires to start
+	 * watching again. This can happen either by tracing that
+	 * triggers a stack trace, or a WARN() that happens during
+	 * coming back from idle, or cpu on or offlining.
+	 *
+	 * is_module_text_address() as well as the kprobe slots,
+	 * is_bpf_text_address() and is_bpf_image_address require
+	 * RCU to be watching.
+	 */
+	no_rcu = !rcu_is_watching();
+
+	/* Treat this like an NMI as it can happen anywhere */
+	if (no_rcu)
+		ct_nmi_enter();
+
+	if (is_module_text_address(addr))
+		goto out;
+	if (is_ftrace_trampoline(addr))
+		goto out;
+	if (is_kprobe_optinsn_slot(addr) || is_kprobe_insn_slot(addr))
+		goto out;
+	if (is_bpf_text_address(addr))
+		goto out;
+	ret = 0;
+out:
+	if (no_rcu)
+		ct_nmi_exit();
+
+	return ret;
+}
+
+/*
+ * On some architectures (PPC64, IA64, PARISC) function pointers
+ * are actually only tokens to some data that then holds the
+ * real function address. As a result, to find if a function
+ * pointer is part of the kernel text, we need to do some
+ * special dereferencing first.
+ */
+#ifdef CONFIG_HAVE_FUNCTION_DESCRIPTORS
+void *dereference_function_descriptor(void *ptr)
+{
+	func_desc_t *desc = ptr;
+	void *p;
+
+	if (!get_kernel_nofault(p, (void *)&desc->addr))
+		ptr = p;
+	return ptr;
+}
+EXPORT_SYMBOL_GPL(dereference_function_descriptor);
+
+void *dereference_kernel_function_descriptor(void *ptr)
+{
+	if (ptr < (void *)__start_opd || ptr >= (void *)__end_opd)
+		return ptr;
+
+	return dereference_function_descriptor(ptr);
+}
+#endif
+
+int func_ptr_is_kernel_text(void *ptr)
+{
+	unsigned long addr;
+	addr = (unsigned long) dereference_function_descriptor(ptr);
+	if (core_kernel_text(addr))
+		return 1;
+	return is_module_text_address(addr);
+}
diff --git a/kernel/fail_function.c b/kernel/fail_function.c
new file mode 100644
index 000000000..d971a0189
--- /dev/null
+++ b/kernel/fail_function.c
@@ -0,0 +1,334 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fail_function.c: Function-based error injection
+ */
+#include <linux/error-injection.h>
+#include <linux/debugfs.h>
+#include <linux/fault-inject.h>
+#include <linux/kallsyms.h>
+#include <linux/kprobes.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
+
+static void fei_post_handler(struct kprobe *kp, struct pt_regs *regs,
+			     unsigned long flags)
+{
+	/*
+	 * A dummy post handler is required to prohibit optimizing, because
+	 * jump optimization does not support execution path overriding.
+	 */
+}
+
+struct fei_attr {
+	struct list_head list;
+	struct kprobe kp;
+	unsigned long retval;
+};
+static DEFINE_MUTEX(fei_lock);
+static LIST_HEAD(fei_attr_list);
+static DECLARE_FAULT_ATTR(fei_fault_attr);
+static struct dentry *fei_debugfs_dir;
+
+static unsigned long adjust_error_retval(unsigned long addr, unsigned long retv)
+{
+	switch (get_injectable_error_type(addr)) {
+	case EI_ETYPE_NULL:
+		return 0;
+	case EI_ETYPE_ERRNO:
+		if (retv < (unsigned long)-MAX_ERRNO)
+			return (unsigned long)-EINVAL;
+		break;
+	case EI_ETYPE_ERRNO_NULL:
+		if (retv != 0 && retv < (unsigned long)-MAX_ERRNO)
+			return (unsigned long)-EINVAL;
+		break;
+	case EI_ETYPE_TRUE:
+		return 1;
+	}
+
+	return retv;
+}
+
+static struct fei_attr *fei_attr_new(const char *sym, unsigned long addr)
+{
+	struct fei_attr *attr;
+
+	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+	if (attr) {
+		attr->kp.symbol_name = kstrdup(sym, GFP_KERNEL);
+		if (!attr->kp.symbol_name) {
+			kfree(attr);
+			return NULL;
+		}
+		attr->kp.pre_handler = fei_kprobe_handler;
+		attr->kp.post_handler = fei_post_handler;
+		attr->retval = adjust_error_retval(addr, 0);
+		INIT_LIST_HEAD(&attr->list);
+	}
+	return attr;
+}
+
+static void fei_attr_free(struct fei_attr *attr)
+{
+	if (attr) {
+		kfree(attr->kp.symbol_name);
+		kfree(attr);
+	}
+}
+
+static struct fei_attr *fei_attr_lookup(const char *sym)
+{
+	struct fei_attr *attr;
+
+	list_for_each_entry(attr, &fei_attr_list, list) {
+		if (!strcmp(attr->kp.symbol_name, sym))
+			return attr;
+	}
+
+	return NULL;
+}
+
+static bool fei_attr_is_valid(struct fei_attr *_attr)
+{
+	struct fei_attr *attr;
+
+	list_for_each_entry(attr, &fei_attr_list, list) {
+		if (attr == _attr)
+			return true;
+	}
+
+	return false;
+}
+
+static int fei_retval_set(void *data, u64 val)
+{
+	struct fei_attr *attr = data;
+	unsigned long retv = (unsigned long)val;
+	int err = 0;
+
+	mutex_lock(&fei_lock);
+	/*
+	 * Since this operation can be done after retval file is removed,
+	 * It is safer to check the attr is still valid before accessing
+	 * its member.
+	 */
+	if (!fei_attr_is_valid(attr)) {
+		err = -ENOENT;
+		goto out;
+	}
+
+	if (attr->kp.addr) {
+		if (adjust_error_retval((unsigned long)attr->kp.addr,
+					val) != retv)
+			err = -EINVAL;
+	}
+	if (!err)
+		attr->retval = val;
+out:
+	mutex_unlock(&fei_lock);
+
+	return err;
+}
+
+static int fei_retval_get(void *data, u64 *val)
+{
+	struct fei_attr *attr = data;
+	int err = 0;
+
+	mutex_lock(&fei_lock);
+	/* Here we also validate @attr to ensure it still exists. */
+	if (!fei_attr_is_valid(attr))
+		err = -ENOENT;
+	else
+		*val = attr->retval;
+	mutex_unlock(&fei_lock);
+
+	return err;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(fei_retval_ops, fei_retval_get, fei_retval_set,
+			 "%llx\n");
+
+static void fei_debugfs_add_attr(struct fei_attr *attr)
+{
+	struct dentry *dir;
+
+	dir = debugfs_create_dir(attr->kp.symbol_name, fei_debugfs_dir);
+
+	debugfs_create_file("retval", 0600, dir, attr, &fei_retval_ops);
+}
+
+static void fei_debugfs_remove_attr(struct fei_attr *attr)
+{
+	debugfs_lookup_and_remove(attr->kp.symbol_name, fei_debugfs_dir);
+}
+
+static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
+{
+	struct fei_attr *attr = container_of(kp, struct fei_attr, kp);
+
+	if (should_fail(&fei_fault_attr, 1)) {
+		regs_set_return_value(regs, attr->retval);
+		override_function_with_return(regs);
+		return 1;
+	}
+
+	return 0;
+}
+NOKPROBE_SYMBOL(fei_kprobe_handler)
+
+static void *fei_seq_start(struct seq_file *m, loff_t *pos)
+{
+	mutex_lock(&fei_lock);
+	return seq_list_start(&fei_attr_list, *pos);
+}
+
+static void fei_seq_stop(struct seq_file *m, void *v)
+{
+	mutex_unlock(&fei_lock);
+}
+
+static void *fei_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return seq_list_next(v, &fei_attr_list, pos);
+}
+
+static int fei_seq_show(struct seq_file *m, void *v)
+{
+	struct fei_attr *attr = list_entry(v, struct fei_attr, list);
+
+	seq_printf(m, "%ps\n", attr->kp.addr);
+	return 0;
+}
+
+static const struct seq_operations fei_seq_ops = {
+	.start	= fei_seq_start,
+	.next	= fei_seq_next,
+	.stop	= fei_seq_stop,
+	.show	= fei_seq_show,
+};
+
+static int fei_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &fei_seq_ops);
+}
+
+static void fei_attr_remove(struct fei_attr *attr)
+{
+	fei_debugfs_remove_attr(attr);
+	unregister_kprobe(&attr->kp);
+	list_del(&attr->list);
+	fei_attr_free(attr);
+}
+
+static void fei_attr_remove_all(void)
+{
+	struct fei_attr *attr, *n;
+
+	list_for_each_entry_safe(attr, n, &fei_attr_list, list) {
+		fei_attr_remove(attr);
+	}
+}
+
+static ssize_t fei_write(struct file *file, const char __user *buffer,
+			 size_t count, loff_t *ppos)
+{
+	struct fei_attr *attr;
+	unsigned long addr;
+	char *buf, *sym;
+	int ret;
+
+	/* cut off if it is too long */
+	if (count > KSYM_NAME_LEN)
+		count = KSYM_NAME_LEN;
+
+	buf = memdup_user_nul(buffer, count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	sym = strstrip(buf);
+
+	mutex_lock(&fei_lock);
+
+	/* Writing just spaces will remove all injection points */
+	if (sym[0] == '\0') {
+		fei_attr_remove_all();
+		ret = count;
+		goto out;
+	}
+	/* Writing !function will remove one injection point */
+	if (sym[0] == '!') {
+		attr = fei_attr_lookup(sym + 1);
+		if (!attr) {
+			ret = -ENOENT;
+			goto out;
+		}
+		fei_attr_remove(attr);
+		ret = count;
+		goto out;
+	}
+
+	addr = kallsyms_lookup_name(sym);
+	if (!addr) {
+		ret = -EINVAL;
+		goto out;
+	}
+	if (!within_error_injection_list(addr)) {
+		ret = -ERANGE;
+		goto out;
+	}
+	if (fei_attr_lookup(sym)) {
+		ret = -EBUSY;
+		goto out;
+	}
+	attr = fei_attr_new(sym, addr);
+	if (!attr) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = register_kprobe(&attr->kp);
+	if (ret) {
+		fei_attr_free(attr);
+		goto out;
+	}
+	fei_debugfs_add_attr(attr);
+	list_add_tail(&attr->list, &fei_attr_list);
+	ret = count;
+out:
+	mutex_unlock(&fei_lock);
+	kfree(buf);
+	return ret;
+}
+
+static const struct file_operations fei_ops = {
+	.open =		fei_open,
+	.read =		seq_read,
+	.write =	fei_write,
+	.llseek =	seq_lseek,
+	.release =	seq_release,
+};
+
+static int __init fei_debugfs_init(void)
+{
+	struct dentry *dir;
+
+	dir = fault_create_debugfs_attr("fail_function", NULL,
+					&fei_fault_attr);
+	if (IS_ERR(dir))
+		return PTR_ERR(dir);
+
+	/* injectable attribute is just a symlink of error_inject/list */
+	debugfs_create_symlink("injectable", dir, "../error_injection/list");
+
+	debugfs_create_file("inject", 0600, dir, NULL, &fei_ops);
+
+	fei_debugfs_dir = dir;
+
+	return 0;
+}
+
+late_initcall(fei_debugfs_init);
diff --git a/kernel/fork.c b/kernel/fork.c
new file mode 100644
index 000000000..856179280
--- /dev/null
+++ b/kernel/fork.c
@@ -0,0 +1,3322 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/kernel/fork.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+/*
+ *  'fork.c' contains the help-routines for the 'fork' system call
+ * (see also entry.S and others).
+ * Fork is rather simple, once you get the hang of it, but the memory
+ * management can be a bitch. See 'mm/memory.c': 'copy_page_range()'
+ */
+
+#include <linux/anon_inodes.h>
+#include <linux/slab.h>
+#include <linux/sched/autogroup.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/coredump.h>
+#include <linux/sched/user.h>
+#include <linux/sched/numa_balancing.h>
+#include <linux/sched/stat.h>
+#include <linux/sched/task.h>
+#include <linux/sched/task_stack.h>
+#include <linux/sched/cputime.h>
+#include <linux/seq_file.h>
+#include <linux/rtmutex.h>
+#include <linux/init.h>
+#include <linux/unistd.h>
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/completion.h>
+#include <linux/personality.h>
+#include <linux/mempolicy.h>
+#include <linux/sem.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/iocontext.h>
+#include <linux/key.h>
+#include <linux/kmsan.h>
+#include <linux/binfmts.h>
+#include <linux/mman.h>
+#include <linux/mmu_notifier.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/mm_inline.h>
+#include <linux/nsproxy.h>
+#include <linux/capability.h>
+#include <linux/cpu.h>
+#include <linux/cgroup.h>
+#include <linux/security.h>
+#include <linux/hugetlb.h>
+#include <linux/seccomp.h>
+#include <linux/swap.h>
+#include <linux/syscalls.h>
+#include <linux/jiffies.h>
+#include <linux/futex.h>
+#include <linux/compat.h>
+#include <linux/kthread.h>
+#include <linux/task_io_accounting_ops.h>
+#include <linux/rcupdate.h>
+#include <linux/ptrace.h>
+#include <linux/mount.h>
+#include <linux/audit.h>
+#include <linux/memcontrol.h>
+#include <linux/ftrace.h>
+#include <linux/proc_fs.h>
+#include <linux/profile.h>
+#include <linux/rmap.h>
+#include <linux/ksm.h>
+#include <linux/acct.h>
+#include <linux/userfaultfd_k.h>
+#include <linux/tsacct_kern.h>
+#include <linux/cn_proc.h>
+#include <linux/freezer.h>
+#include <linux/delayacct.h>
+#include <linux/taskstats_kern.h>
+#include <linux/random.h>
+#include <linux/tty.h>
+#include <linux/fs_struct.h>
+#include <linux/magic.h>
+#include <linux/perf_event.h>
+#include <linux/posix-timers.h>
+#include <linux/user-return-notifier.h>
+#include <linux/oom.h>
+#include <linux/khugepaged.h>
+#include <linux/signalfd.h>
+#include <linux/uprobes.h>
+#include <linux/aio.h>
+#include <linux/compiler.h>
+#include <linux/sysctl.h>
+#include <linux/kcov.h>
+#include <linux/livepatch.h>
+#include <linux/thread_info.h>
+#include <linux/stackleak.h>
+#include <linux/kasan.h>
+#include <linux/scs.h>
+#include <linux/io_uring.h>
+#include <linux/bpf.h>
+
+#include <asm/pgalloc.h>
+#include <linux/uaccess.h>
+#include <asm/mmu_context.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+
+#include <trace/events/sched.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/task.h>
+
+/*
+ * Minimum number of threads to boot the kernel
+ */
+#define MIN_THREADS 20
+
+/*
+ * Maximum number of threads
+ */
+#define MAX_THREADS FUTEX_TID_MASK
+
+/*
+ * Protected counters by write_lock_irq(&tasklist_lock)
+ */
+unsigned long total_forks;	/* Handle normal Linux uptimes. */
+int nr_threads;			/* The idle threads do not count.. */
+
+static int max_threads;		/* tunable limit on nr_threads */
+
+#define NAMED_ARRAY_INDEX(x)	[x] = __stringify(x)
+
+static const char * const resident_page_types[] = {
+	NAMED_ARRAY_INDEX(MM_FILEPAGES),
+	NAMED_ARRAY_INDEX(MM_ANONPAGES),
+	NAMED_ARRAY_INDEX(MM_SWAPENTS),
+	NAMED_ARRAY_INDEX(MM_SHMEMPAGES),
+};
+
+DEFINE_PER_CPU(unsigned long, process_counts) = 0;
+
+__cacheline_aligned DEFINE_RWLOCK(tasklist_lock);  /* outer */
+
+#ifdef CONFIG_PROVE_RCU
+int lockdep_tasklist_lock_is_held(void)
+{
+	return lockdep_is_held(&tasklist_lock);
+}
+EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held);
+#endif /* #ifdef CONFIG_PROVE_RCU */
+
+int nr_processes(void)
+{
+	int cpu;
+	int total = 0;
+
+	for_each_possible_cpu(cpu)
+		total += per_cpu(process_counts, cpu);
+
+	return total;
+}
+
+void __weak arch_release_task_struct(struct task_struct *tsk)
+{
+}
+
+#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
+static struct kmem_cache *task_struct_cachep;
+
+static inline struct task_struct *alloc_task_struct_node(int node)
+{
+	return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node);
+}
+
+static inline void free_task_struct(struct task_struct *tsk)
+{
+	kmem_cache_free(task_struct_cachep, tsk);
+}
+#endif
+
+#ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR
+
+/*
+ * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a
+ * kmemcache based allocator.
+ */
+# if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)
+
+#  ifdef CONFIG_VMAP_STACK
+/*
+ * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB
+ * flush.  Try to minimize the number of calls by caching stacks.
+ */
+#define NR_CACHED_STACKS 2
+static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
+
+struct vm_stack {
+	struct rcu_head rcu;
+	struct vm_struct *stack_vm_area;
+};
+
+static bool try_release_thread_stack_to_cache(struct vm_struct *vm)
+{
+	unsigned int i;
+
+	for (i = 0; i < NR_CACHED_STACKS; i++) {
+		if (this_cpu_cmpxchg(cached_stacks[i], NULL, vm) != NULL)
+			continue;
+		return true;
+	}
+	return false;
+}
+
+static void thread_stack_free_rcu(struct rcu_head *rh)
+{
+	struct vm_stack *vm_stack = container_of(rh, struct vm_stack, rcu);
+
+	if (try_release_thread_stack_to_cache(vm_stack->stack_vm_area))
+		return;
+
+	vfree(vm_stack);
+}
+
+static void thread_stack_delayed_free(struct task_struct *tsk)
+{
+	struct vm_stack *vm_stack = tsk->stack;
+
+	vm_stack->stack_vm_area = tsk->stack_vm_area;
+	call_rcu(&vm_stack->rcu, thread_stack_free_rcu);
+}
+
+static int free_vm_stack_cache(unsigned int cpu)
+{
+	struct vm_struct **cached_vm_stacks = per_cpu_ptr(cached_stacks, cpu);
+	int i;
+
+	for (i = 0; i < NR_CACHED_STACKS; i++) {
+		struct vm_struct *vm_stack = cached_vm_stacks[i];
+
+		if (!vm_stack)
+			continue;
+
+		vfree(vm_stack->addr);
+		cached_vm_stacks[i] = NULL;
+	}
+
+	return 0;
+}
+
+static int memcg_charge_kernel_stack(struct vm_struct *vm)
+{
+	int i;
+	int ret;
+
+	BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0);
+	BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);
+
+	for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
+		ret = memcg_kmem_charge_page(vm->pages[i], GFP_KERNEL, 0);
+		if (ret)
+			goto err;
+	}
+	return 0;
+err:
+	/*
+	 * If memcg_kmem_charge_page() fails, page's memory cgroup pointer is
+	 * NULL, and memcg_kmem_uncharge_page() in free_thread_stack() will
+	 * ignore this page.
+	 */
+	for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
+		memcg_kmem_uncharge_page(vm->pages[i], 0);
+	return ret;
+}
+
+static int alloc_thread_stack_node(struct task_struct *tsk, int node)
+{
+	struct vm_struct *vm;
+	void *stack;
+	int i;
+
+	for (i = 0; i < NR_CACHED_STACKS; i++) {
+		struct vm_struct *s;
+
+		s = this_cpu_xchg(cached_stacks[i], NULL);
+
+		if (!s)
+			continue;
+
+		/* Reset stack metadata. */
+		kasan_unpoison_range(s->addr, THREAD_SIZE);
+
+		stack = kasan_reset_tag(s->addr);
+
+		/* Clear stale pointers from reused stack. */
+		memset(stack, 0, THREAD_SIZE);
+
+		if (memcg_charge_kernel_stack(s)) {
+			vfree(s->addr);
+			return -ENOMEM;
+		}
+
+		tsk->stack_vm_area = s;
+		tsk->stack = stack;
+		return 0;
+	}
+
+	/*
+	 * Allocated stacks are cached and later reused by new threads,
+	 * so memcg accounting is performed manually on assigning/releasing
+	 * stacks to tasks. Drop __GFP_ACCOUNT.
+	 */
+	stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN,
+				     VMALLOC_START, VMALLOC_END,
+				     THREADINFO_GFP & ~__GFP_ACCOUNT,
+				     PAGE_KERNEL,
+				     0, node, __builtin_return_address(0));
+	if (!stack)
+		return -ENOMEM;
+
+	vm = find_vm_area(stack);
+	if (memcg_charge_kernel_stack(vm)) {
+		vfree(stack);
+		return -ENOMEM;
+	}
+	/*
+	 * We can't call find_vm_area() in interrupt context, and
+	 * free_thread_stack() can be called in interrupt context,
+	 * so cache the vm_struct.
+	 */
+	tsk->stack_vm_area = vm;
+	stack = kasan_reset_tag(stack);
+	tsk->stack = stack;
+	return 0;
+}
+
+static void free_thread_stack(struct task_struct *tsk)
+{
+	if (!try_release_thread_stack_to_cache(tsk->stack_vm_area))
+		thread_stack_delayed_free(tsk);
+
+	tsk->stack = NULL;
+	tsk->stack_vm_area = NULL;
+}
+
+#  else /* !CONFIG_VMAP_STACK */
+
+static void thread_stack_free_rcu(struct rcu_head *rh)
+{
+	__free_pages(virt_to_page(rh), THREAD_SIZE_ORDER);
+}
+
+static void thread_stack_delayed_free(struct task_struct *tsk)
+{
+	struct rcu_head *rh = tsk->stack;
+
+	call_rcu(rh, thread_stack_free_rcu);
+}
+
+static int alloc_thread_stack_node(struct task_struct *tsk, int node)
+{
+	struct page *page = alloc_pages_node(node, THREADINFO_GFP,
+					     THREAD_SIZE_ORDER);
+
+	if (likely(page)) {
+		tsk->stack = kasan_reset_tag(page_address(page));
+		return 0;
+	}
+	return -ENOMEM;
+}
+
+static void free_thread_stack(struct task_struct *tsk)
+{
+	thread_stack_delayed_free(tsk);
+	tsk->stack = NULL;
+}
+
+#  endif /* CONFIG_VMAP_STACK */
+# else /* !(THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)) */
+
+static struct kmem_cache *thread_stack_cache;
+
+static void thread_stack_free_rcu(struct rcu_head *rh)
+{
+	kmem_cache_free(thread_stack_cache, rh);
+}
+
+static void thread_stack_delayed_free(struct task_struct *tsk)
+{
+	struct rcu_head *rh = tsk->stack;
+
+	call_rcu(rh, thread_stack_free_rcu);
+}
+
+static int alloc_thread_stack_node(struct task_struct *tsk, int node)
+{
+	unsigned long *stack;
+	stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node);
+	stack = kasan_reset_tag(stack);
+	tsk->stack = stack;
+	return stack ? 0 : -ENOMEM;
+}
+
+static void free_thread_stack(struct task_struct *tsk)
+{
+	thread_stack_delayed_free(tsk);
+	tsk->stack = NULL;
+}
+
+void thread_stack_cache_init(void)
+{
+	thread_stack_cache = kmem_cache_create_usercopy("thread_stack",
+					THREAD_SIZE, THREAD_SIZE, 0, 0,
+					THREAD_SIZE, NULL);
+	BUG_ON(thread_stack_cache == NULL);
+}
+
+# endif /* THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) */
+#else /* CONFIG_ARCH_THREAD_STACK_ALLOCATOR */
+
+static int alloc_thread_stack_node(struct task_struct *tsk, int node)
+{
+	unsigned long *stack;
+
+	stack = arch_alloc_thread_stack_node(tsk, node);
+	tsk->stack = stack;
+	return stack ? 0 : -ENOMEM;
+}
+
+static void free_thread_stack(struct task_struct *tsk)
+{
+	arch_free_thread_stack(tsk);
+	tsk->stack = NULL;
+}
+
+#endif /* !CONFIG_ARCH_THREAD_STACK_ALLOCATOR */
+
+/* SLAB cache for signal_struct structures (tsk->signal) */
+static struct kmem_cache *signal_cachep;
+
+/* SLAB cache for sighand_struct structures (tsk->sighand) */
+struct kmem_cache *sighand_cachep;
+
+/* SLAB cache for files_struct structures (tsk->files) */
+struct kmem_cache *files_cachep;
+
+/* SLAB cache for fs_struct structures (tsk->fs) */
+struct kmem_cache *fs_cachep;
+
+/* SLAB cache for vm_area_struct structures */
+static struct kmem_cache *vm_area_cachep;
+
+/* SLAB cache for mm_struct structures (tsk->mm) */
+static struct kmem_cache *mm_cachep;
+
+struct vm_area_struct *vm_area_alloc(struct mm_struct *mm)
+{
+	struct vm_area_struct *vma;
+
+	vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
+	if (vma)
+		vma_init(vma, mm);
+	return vma;
+}
+
+struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
+{
+	struct vm_area_struct *new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
+
+	if (new) {
+		ASSERT_EXCLUSIVE_WRITER(orig->vm_flags);
+		ASSERT_EXCLUSIVE_WRITER(orig->vm_file);
+		/*
+		 * orig->shared.rb may be modified concurrently, but the clone
+		 * will be reinitialized.
+		 */
+		*new = data_race(*orig);
+		INIT_LIST_HEAD(&new->anon_vma_chain);
+		dup_anon_vma_name(orig, new);
+	}
+	return new;
+}
+
+void vm_area_free(struct vm_area_struct *vma)
+{
+	free_anon_vma_name(vma);
+	kmem_cache_free(vm_area_cachep, vma);
+}
+
+static void account_kernel_stack(struct task_struct *tsk, int account)
+{
+	if (IS_ENABLED(CONFIG_VMAP_STACK)) {
+		struct vm_struct *vm = task_stack_vm_area(tsk);
+		int i;
+
+		for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
+			mod_lruvec_page_state(vm->pages[i], NR_KERNEL_STACK_KB,
+					      account * (PAGE_SIZE / 1024));
+	} else {
+		void *stack = task_stack_page(tsk);
+
+		/* All stack pages are in the same node. */
+		mod_lruvec_kmem_state(stack, NR_KERNEL_STACK_KB,
+				      account * (THREAD_SIZE / 1024));
+	}
+}
+
+void exit_task_stack_account(struct task_struct *tsk)
+{
+	account_kernel_stack(tsk, -1);
+
+	if (IS_ENABLED(CONFIG_VMAP_STACK)) {
+		struct vm_struct *vm;
+		int i;
+
+		vm = task_stack_vm_area(tsk);
+		for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
+			memcg_kmem_uncharge_page(vm->pages[i], 0);
+	}
+}
+
+static void release_task_stack(struct task_struct *tsk)
+{
+	if (WARN_ON(READ_ONCE(tsk->__state) != TASK_DEAD))
+		return;  /* Better to leak the stack than to free prematurely */
+
+	free_thread_stack(tsk);
+}
+
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+void put_task_stack(struct task_struct *tsk)
+{
+	if (refcount_dec_and_test(&tsk->stack_refcount))
+		release_task_stack(tsk);
+}
+#endif
+
+void free_task(struct task_struct *tsk)
+{
+#ifdef CONFIG_SECCOMP
+	WARN_ON_ONCE(tsk->seccomp.filter);
+#endif
+	release_user_cpus_ptr(tsk);
+	scs_release(tsk);
+
+#ifndef CONFIG_THREAD_INFO_IN_TASK
+	/*
+	 * The task is finally done with both the stack and thread_info,
+	 * so free both.
+	 */
+	release_task_stack(tsk);
+#else
+	/*
+	 * If the task had a separate stack allocation, it should be gone
+	 * by now.
+	 */
+	WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0);
+#endif
+	rt_mutex_debug_task_free(tsk);
+	ftrace_graph_exit_task(tsk);
+	arch_release_task_struct(tsk);
+	if (tsk->flags & PF_KTHREAD)
+		free_kthread_struct(tsk);
+	bpf_task_storage_free(tsk);
+	free_task_struct(tsk);
+}
+EXPORT_SYMBOL(free_task);
+
+static void dup_mm_exe_file(struct mm_struct *mm, struct mm_struct *oldmm)
+{
+	struct file *exe_file;
+
+	exe_file = get_mm_exe_file(oldmm);
+	RCU_INIT_POINTER(mm->exe_file, exe_file);
+	/*
+	 * We depend on the oldmm having properly denied write access to the
+	 * exe_file already.
+	 */
+	if (exe_file && deny_write_access(exe_file))
+		pr_warn_once("deny_write_access() failed in %s\n", __func__);
+}
+
+#ifdef CONFIG_MMU
+static __latent_entropy int dup_mmap(struct mm_struct *mm,
+					struct mm_struct *oldmm)
+{
+	struct vm_area_struct *mpnt, *tmp;
+	int retval;
+	unsigned long charge = 0;
+	LIST_HEAD(uf);
+	MA_STATE(old_mas, &oldmm->mm_mt, 0, 0);
+	MA_STATE(mas, &mm->mm_mt, 0, 0);
+
+	uprobe_start_dup_mmap();
+	if (mmap_write_lock_killable(oldmm)) {
+		retval = -EINTR;
+		goto fail_uprobe_end;
+	}
+	flush_cache_dup_mm(oldmm);
+	uprobe_dup_mmap(oldmm, mm);
+	/*
+	 * Not linked in yet - no deadlock potential:
+	 */
+	mmap_write_lock_nested(mm, SINGLE_DEPTH_NESTING);
+
+	/* No ordering required: file already has been exposed. */
+	dup_mm_exe_file(mm, oldmm);
+
+	mm->total_vm = oldmm->total_vm;
+	mm->data_vm = oldmm->data_vm;
+	mm->exec_vm = oldmm->exec_vm;
+	mm->stack_vm = oldmm->stack_vm;
+
+	retval = ksm_fork(mm, oldmm);
+	if (retval)
+		goto out;
+	khugepaged_fork(mm, oldmm);
+
+	retval = mas_expected_entries(&mas, oldmm->map_count);
+	if (retval)
+		goto out;
+
+	mt_clear_in_rcu(mas.tree);
+	mas_for_each(&old_mas, mpnt, ULONG_MAX) {
+		struct file *file;
+
+		if (mpnt->vm_flags & VM_DONTCOPY) {
+			vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt));
+			continue;
+		}
+		charge = 0;
+		/*
+		 * Don't duplicate many vmas if we've been oom-killed (for
+		 * example)
+		 */
+		if (fatal_signal_pending(current)) {
+			retval = -EINTR;
+			goto loop_out;
+		}
+		if (mpnt->vm_flags & VM_ACCOUNT) {
+			unsigned long len = vma_pages(mpnt);
+
+			if (security_vm_enough_memory_mm(oldmm, len)) /* sic */
+				goto fail_nomem;
+			charge = len;
+		}
+		tmp = vm_area_dup(mpnt);
+		if (!tmp)
+			goto fail_nomem;
+		retval = vma_dup_policy(mpnt, tmp);
+		if (retval)
+			goto fail_nomem_policy;
+		tmp->vm_mm = mm;
+		retval = dup_userfaultfd(tmp, &uf);
+		if (retval)
+			goto fail_nomem_anon_vma_fork;
+		if (tmp->vm_flags & VM_WIPEONFORK) {
+			/*
+			 * VM_WIPEONFORK gets a clean slate in the child.
+			 * Don't prepare anon_vma until fault since we don't
+			 * copy page for current vma.
+			 */
+			tmp->anon_vma = NULL;
+		} else if (anon_vma_fork(tmp, mpnt))
+			goto fail_nomem_anon_vma_fork;
+		tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT);
+		file = tmp->vm_file;
+		if (file) {
+			struct address_space *mapping = file->f_mapping;
+
+			get_file(file);
+			i_mmap_lock_write(mapping);
+			if (tmp->vm_flags & VM_SHARED)
+				mapping_allow_writable(mapping);
+			flush_dcache_mmap_lock(mapping);
+			/* insert tmp into the share list, just after mpnt */
+			vma_interval_tree_insert_after(tmp, mpnt,
+					&mapping->i_mmap);
+			flush_dcache_mmap_unlock(mapping);
+			i_mmap_unlock_write(mapping);
+		}
+
+		/*
+		 * Copy/update hugetlb private vma information.
+		 */
+		if (is_vm_hugetlb_page(tmp))
+			hugetlb_dup_vma_private(tmp);
+
+		/* Link the vma into the MT */
+		mas.index = tmp->vm_start;
+		mas.last = tmp->vm_end - 1;
+		mas_store(&mas, tmp);
+		if (mas_is_err(&mas))
+			goto fail_nomem_mas_store;
+
+		mm->map_count++;
+		if (!(tmp->vm_flags & VM_WIPEONFORK))
+			retval = copy_page_range(tmp, mpnt);
+
+		if (tmp->vm_ops && tmp->vm_ops->open)
+			tmp->vm_ops->open(tmp);
+
+		if (retval)
+			goto loop_out;
+	}
+	/* a new mm has just been created */
+	retval = arch_dup_mmap(oldmm, mm);
+loop_out:
+	mas_destroy(&mas);
+	if (!retval)
+		mt_set_in_rcu(mas.tree);
+out:
+	mmap_write_unlock(mm);
+	flush_tlb_mm(oldmm);
+	mmap_write_unlock(oldmm);
+	dup_userfaultfd_complete(&uf);
+fail_uprobe_end:
+	uprobe_end_dup_mmap();
+	return retval;
+
+fail_nomem_mas_store:
+	unlink_anon_vmas(tmp);
+fail_nomem_anon_vma_fork:
+	mpol_put(vma_policy(tmp));
+fail_nomem_policy:
+	vm_area_free(tmp);
+fail_nomem:
+	retval = -ENOMEM;
+	vm_unacct_memory(charge);
+	goto loop_out;
+}
+
+static inline int mm_alloc_pgd(struct mm_struct *mm)
+{
+	mm->pgd = pgd_alloc(mm);
+	if (unlikely(!mm->pgd))
+		return -ENOMEM;
+	return 0;
+}
+
+static inline void mm_free_pgd(struct mm_struct *mm)
+{
+	pgd_free(mm, mm->pgd);
+}
+#else
+static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
+{
+	mmap_write_lock(oldmm);
+	dup_mm_exe_file(mm, oldmm);
+	mmap_write_unlock(oldmm);
+	return 0;
+}
+#define mm_alloc_pgd(mm)	(0)
+#define mm_free_pgd(mm)
+#endif /* CONFIG_MMU */
+
+static void check_mm(struct mm_struct *mm)
+{
+	int i;
+
+	BUILD_BUG_ON_MSG(ARRAY_SIZE(resident_page_types) != NR_MM_COUNTERS,
+			 "Please make sure 'struct resident_page_types[]' is updated as well");
+
+	for (i = 0; i < NR_MM_COUNTERS; i++) {
+		long x = atomic_long_read(&mm->rss_stat.count[i]);
+
+		if (unlikely(x))
+			pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld\n",
+				 mm, resident_page_types[i], x);
+	}
+
+	if (mm_pgtables_bytes(mm))
+		pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n",
+				mm_pgtables_bytes(mm));
+
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
+	VM_BUG_ON_MM(mm->pmd_huge_pte, mm);
+#endif
+}
+
+#define allocate_mm()	(kmem_cache_alloc(mm_cachep, GFP_KERNEL))
+#define free_mm(mm)	(kmem_cache_free(mm_cachep, (mm)))
+
+/*
+ * Called when the last reference to the mm
+ * is dropped: either by a lazy thread or by
+ * mmput. Free the page directory and the mm.
+ */
+void __mmdrop(struct mm_struct *mm)
+{
+	BUG_ON(mm == &init_mm);
+	WARN_ON_ONCE(mm == current->mm);
+	WARN_ON_ONCE(mm == current->active_mm);
+	mm_free_pgd(mm);
+	destroy_context(mm);
+	mmu_notifier_subscriptions_destroy(mm);
+	check_mm(mm);
+	put_user_ns(mm->user_ns);
+	mm_pasid_drop(mm);
+	free_mm(mm);
+}
+EXPORT_SYMBOL_GPL(__mmdrop);
+
+static void mmdrop_async_fn(struct work_struct *work)
+{
+	struct mm_struct *mm;
+
+	mm = container_of(work, struct mm_struct, async_put_work);
+	__mmdrop(mm);
+}
+
+static void mmdrop_async(struct mm_struct *mm)
+{
+	if (unlikely(atomic_dec_and_test(&mm->mm_count))) {
+		INIT_WORK(&mm->async_put_work, mmdrop_async_fn);
+		schedule_work(&mm->async_put_work);
+	}
+}
+
+static inline void free_signal_struct(struct signal_struct *sig)
+{
+	taskstats_tgid_free(sig);
+	sched_autogroup_exit(sig);
+	/*
+	 * __mmdrop is not safe to call from softirq context on x86 due to
+	 * pgd_dtor so postpone it to the async context
+	 */
+	if (sig->oom_mm)
+		mmdrop_async(sig->oom_mm);
+	kmem_cache_free(signal_cachep, sig);
+}
+
+static inline void put_signal_struct(struct signal_struct *sig)
+{
+	if (refcount_dec_and_test(&sig->sigcnt))
+		free_signal_struct(sig);
+}
+
+void __put_task_struct(struct task_struct *tsk)
+{
+	WARN_ON(!tsk->exit_state);
+	WARN_ON(refcount_read(&tsk->usage));
+	WARN_ON(tsk == current);
+
+	io_uring_free(tsk);
+	cgroup_free(tsk);
+	task_numa_free(tsk, true);
+	security_task_free(tsk);
+	exit_creds(tsk);
+	delayacct_tsk_free(tsk);
+	put_signal_struct(tsk->signal);
+	sched_core_free(tsk);
+	free_task(tsk);
+}
+EXPORT_SYMBOL_GPL(__put_task_struct);
+
+void __put_task_struct_rcu_cb(struct rcu_head *rhp)
+{
+	struct task_struct *task = container_of(rhp, struct task_struct, rcu);
+
+	__put_task_struct(task);
+}
+EXPORT_SYMBOL_GPL(__put_task_struct_rcu_cb);
+
+void __init __weak arch_task_cache_init(void) { }
+
+/*
+ * set_max_threads
+ */
+static void set_max_threads(unsigned int max_threads_suggested)
+{
+	u64 threads;
+	unsigned long nr_pages = totalram_pages();
+
+	/*
+	 * The number of threads shall be limited such that the thread
+	 * structures may only consume a small part of the available memory.
+	 */
+	if (fls64(nr_pages) + fls64(PAGE_SIZE) > 64)
+		threads = MAX_THREADS;
+	else
+		threads = div64_u64((u64) nr_pages * (u64) PAGE_SIZE,
+				    (u64) THREAD_SIZE * 8UL);
+
+	if (threads > max_threads_suggested)
+		threads = max_threads_suggested;
+
+	max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS);
+}
+
+#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
+/* Initialized by the architecture: */
+int arch_task_struct_size __read_mostly;
+#endif
+
+#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
+static void task_struct_whitelist(unsigned long *offset, unsigned long *size)
+{
+	/* Fetch thread_struct whitelist for the architecture. */
+	arch_thread_struct_whitelist(offset, size);
+
+	/*
+	 * Handle zero-sized whitelist or empty thread_struct, otherwise
+	 * adjust offset to position of thread_struct in task_struct.
+	 */
+	if (unlikely(*size == 0))
+		*offset = 0;
+	else
+		*offset += offsetof(struct task_struct, thread);
+}
+#endif /* CONFIG_ARCH_TASK_STRUCT_ALLOCATOR */
+
+void __init fork_init(void)
+{
+	int i;
+#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
+#ifndef ARCH_MIN_TASKALIGN
+#define ARCH_MIN_TASKALIGN	0
+#endif
+	int align = max_t(int, L1_CACHE_BYTES, ARCH_MIN_TASKALIGN);
+	unsigned long useroffset, usersize;
+
+	/* create a slab on which task_structs can be allocated */
+	task_struct_whitelist(&useroffset, &usersize);
+	task_struct_cachep = kmem_cache_create_usercopy("task_struct",
+			arch_task_struct_size, align,
+			SLAB_PANIC|SLAB_ACCOUNT,
+			useroffset, usersize, NULL);
+#endif
+
+	/* do the arch specific task caches init */
+	arch_task_cache_init();
+
+	set_max_threads(MAX_THREADS);
+
+	init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
+	init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
+	init_task.signal->rlim[RLIMIT_SIGPENDING] =
+		init_task.signal->rlim[RLIMIT_NPROC];
+
+	for (i = 0; i < UCOUNT_COUNTS; i++)
+		init_user_ns.ucount_max[i] = max_threads/2;
+
+	set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_NPROC,      RLIM_INFINITY);
+	set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE,   RLIM_INFINITY);
+	set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, RLIM_INFINITY);
+	set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK,    RLIM_INFINITY);
+
+#ifdef CONFIG_VMAP_STACK
+	cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache",
+			  NULL, free_vm_stack_cache);
+#endif
+
+	scs_init();
+
+	lockdep_init_task(&init_task);
+	uprobes_init();
+}
+
+int __weak arch_dup_task_struct(struct task_struct *dst,
+					       struct task_struct *src)
+{
+	*dst = *src;
+	return 0;
+}
+
+void set_task_stack_end_magic(struct task_struct *tsk)
+{
+	unsigned long *stackend;
+
+	stackend = end_of_stack(tsk);
+	*stackend = STACK_END_MAGIC;	/* for overflow detection */
+}
+
+static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
+{
+	struct task_struct *tsk;
+	int err;
+
+	if (node == NUMA_NO_NODE)
+		node = tsk_fork_get_node(orig);
+	tsk = alloc_task_struct_node(node);
+	if (!tsk)
+		return NULL;
+
+	err = arch_dup_task_struct(tsk, orig);
+	if (err)
+		goto free_tsk;
+
+	err = alloc_thread_stack_node(tsk, node);
+	if (err)
+		goto free_tsk;
+
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+	refcount_set(&tsk->stack_refcount, 1);
+#endif
+	account_kernel_stack(tsk, 1);
+
+	err = scs_prepare(tsk, node);
+	if (err)
+		goto free_stack;
+
+#ifdef CONFIG_SECCOMP
+	/*
+	 * We must handle setting up seccomp filters once we're under
+	 * the sighand lock in case orig has changed between now and
+	 * then. Until then, filter must be NULL to avoid messing up
+	 * the usage counts on the error path calling free_task.
+	 */
+	tsk->seccomp.filter = NULL;
+#endif
+
+	setup_thread_stack(tsk, orig);
+	clear_user_return_notifier(tsk);
+	clear_tsk_need_resched(tsk);
+	set_task_stack_end_magic(tsk);
+	clear_syscall_work_syscall_user_dispatch(tsk);
+
+#ifdef CONFIG_STACKPROTECTOR
+	tsk->stack_canary = get_random_canary();
+#endif
+	if (orig->cpus_ptr == &orig->cpus_mask)
+		tsk->cpus_ptr = &tsk->cpus_mask;
+	dup_user_cpus_ptr(tsk, orig, node);
+
+	/*
+	 * One for the user space visible state that goes away when reaped.
+	 * One for the scheduler.
+	 */
+	refcount_set(&tsk->rcu_users, 2);
+	/* One for the rcu users */
+	refcount_set(&tsk->usage, 1);
+#ifdef CONFIG_BLK_DEV_IO_TRACE
+	tsk->btrace_seq = 0;
+#endif
+	tsk->splice_pipe = NULL;
+	tsk->task_frag.page = NULL;
+	tsk->wake_q.next = NULL;
+	tsk->worker_private = NULL;
+
+	kcov_task_init(tsk);
+	kmsan_task_create(tsk);
+	kmap_local_fork(tsk);
+
+#ifdef CONFIG_FAULT_INJECTION
+	tsk->fail_nth = 0;
+#endif
+
+#ifdef CONFIG_BLK_CGROUP
+	tsk->throttle_queue = NULL;
+	tsk->use_memdelay = 0;
+#endif
+
+#ifdef CONFIG_IOMMU_SVA
+	tsk->pasid_activated = 0;
+#endif
+
+#ifdef CONFIG_MEMCG
+	tsk->active_memcg = NULL;
+#endif
+
+#ifdef CONFIG_CPU_SUP_INTEL
+	tsk->reported_split_lock = 0;
+#endif
+
+	return tsk;
+
+free_stack:
+	exit_task_stack_account(tsk);
+	free_thread_stack(tsk);
+free_tsk:
+	free_task_struct(tsk);
+	return NULL;
+}
+
+__cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);
+
+static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT;
+
+static int __init coredump_filter_setup(char *s)
+{
+	default_dump_filter =
+		(simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) &
+		MMF_DUMP_FILTER_MASK;
+	return 1;
+}
+
+__setup("coredump_filter=", coredump_filter_setup);
+
+#include <linux/init_task.h>
+
+static void mm_init_aio(struct mm_struct *mm)
+{
+#ifdef CONFIG_AIO
+	spin_lock_init(&mm->ioctx_lock);
+	mm->ioctx_table = NULL;
+#endif
+}
+
+static __always_inline void mm_clear_owner(struct mm_struct *mm,
+					   struct task_struct *p)
+{
+#ifdef CONFIG_MEMCG
+	if (mm->owner == p)
+		WRITE_ONCE(mm->owner, NULL);
+#endif
+}
+
+static void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
+{
+#ifdef CONFIG_MEMCG
+	mm->owner = p;
+#endif
+}
+
+static void mm_init_uprobes_state(struct mm_struct *mm)
+{
+#ifdef CONFIG_UPROBES
+	mm->uprobes_state.xol_area = NULL;
+#endif
+}
+
+static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
+	struct user_namespace *user_ns)
+{
+	mt_init_flags(&mm->mm_mt, MM_MT_FLAGS);
+	mt_set_external_lock(&mm->mm_mt, &mm->mmap_lock);
+	atomic_set(&mm->mm_users, 1);
+	atomic_set(&mm->mm_count, 1);
+	seqcount_init(&mm->write_protect_seq);
+	mmap_init_lock(mm);
+	INIT_LIST_HEAD(&mm->mmlist);
+	mm_pgtables_bytes_init(mm);
+	mm->map_count = 0;
+	mm->locked_vm = 0;
+	atomic64_set(&mm->pinned_vm, 0);
+	memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
+	spin_lock_init(&mm->page_table_lock);
+	spin_lock_init(&mm->arg_lock);
+	mm_init_cpumask(mm);
+	mm_init_aio(mm);
+	mm_init_owner(mm, p);
+	mm_pasid_init(mm);
+	RCU_INIT_POINTER(mm->exe_file, NULL);
+	mmu_notifier_subscriptions_init(mm);
+	init_tlb_flush_pending(mm);
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
+	mm->pmd_huge_pte = NULL;
+#endif
+	mm_init_uprobes_state(mm);
+	hugetlb_count_init(mm);
+
+	if (current->mm) {
+		mm->flags = current->mm->flags & MMF_INIT_MASK;
+		mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK;
+	} else {
+		mm->flags = default_dump_filter;
+		mm->def_flags = 0;
+	}
+
+	if (mm_alloc_pgd(mm))
+		goto fail_nopgd;
+
+	if (init_new_context(p, mm))
+		goto fail_nocontext;
+
+	mm->user_ns = get_user_ns(user_ns);
+	lru_gen_init_mm(mm);
+	return mm;
+
+fail_nocontext:
+	mm_free_pgd(mm);
+fail_nopgd:
+	free_mm(mm);
+	return NULL;
+}
+
+/*
+ * Allocate and initialize an mm_struct.
+ */
+struct mm_struct *mm_alloc(void)
+{
+	struct mm_struct *mm;
+
+	mm = allocate_mm();
+	if (!mm)
+		return NULL;
+
+	memset(mm, 0, sizeof(*mm));
+	return mm_init(mm, current, current_user_ns());
+}
+
+static inline void __mmput(struct mm_struct *mm)
+{
+	VM_BUG_ON(atomic_read(&mm->mm_users));
+
+	uprobe_clear_state(mm);
+	exit_aio(mm);
+	ksm_exit(mm);
+	khugepaged_exit(mm); /* must run before exit_mmap */
+	exit_mmap(mm);
+	mm_put_huge_zero_page(mm);
+	set_mm_exe_file(mm, NULL);
+	if (!list_empty(&mm->mmlist)) {
+		spin_lock(&mmlist_lock);
+		list_del(&mm->mmlist);
+		spin_unlock(&mmlist_lock);
+	}
+	if (mm->binfmt)
+		module_put(mm->binfmt->module);
+	lru_gen_del_mm(mm);
+	mmdrop(mm);
+}
+
+/*
+ * Decrement the use count and release all resources for an mm.
+ */
+void mmput(struct mm_struct *mm)
+{
+	might_sleep();
+
+	if (atomic_dec_and_test(&mm->mm_users))
+		__mmput(mm);
+}
+EXPORT_SYMBOL_GPL(mmput);
+
+#ifdef CONFIG_MMU
+static void mmput_async_fn(struct work_struct *work)
+{
+	struct mm_struct *mm = container_of(work, struct mm_struct,
+					    async_put_work);
+
+	__mmput(mm);
+}
+
+void mmput_async(struct mm_struct *mm)
+{
+	if (atomic_dec_and_test(&mm->mm_users)) {
+		INIT_WORK(&mm->async_put_work, mmput_async_fn);
+		schedule_work(&mm->async_put_work);
+	}
+}
+EXPORT_SYMBOL_GPL(mmput_async);
+#endif
+
+/**
+ * set_mm_exe_file - change a reference to the mm's executable file
+ *
+ * This changes mm's executable file (shown as symlink /proc/[pid]/exe).
+ *
+ * Main users are mmput() and sys_execve(). Callers prevent concurrent
+ * invocations: in mmput() nobody alive left, in execve task is single
+ * threaded.
+ *
+ * Can only fail if new_exe_file != NULL.
+ */
+int set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
+{
+	struct file *old_exe_file;
+
+	/*
+	 * It is safe to dereference the exe_file without RCU as
+	 * this function is only called if nobody else can access
+	 * this mm -- see comment above for justification.
+	 */
+	old_exe_file = rcu_dereference_raw(mm->exe_file);
+
+	if (new_exe_file) {
+		/*
+		 * We expect the caller (i.e., sys_execve) to already denied
+		 * write access, so this is unlikely to fail.
+		 */
+		if (unlikely(deny_write_access(new_exe_file)))
+			return -EACCES;
+		get_file(new_exe_file);
+	}
+	rcu_assign_pointer(mm->exe_file, new_exe_file);
+	if (old_exe_file) {
+		allow_write_access(old_exe_file);
+		fput(old_exe_file);
+	}
+	return 0;
+}
+
+/**
+ * replace_mm_exe_file - replace a reference to the mm's executable file
+ *
+ * This changes mm's executable file (shown as symlink /proc/[pid]/exe),
+ * dealing with concurrent invocation and without grabbing the mmap lock in
+ * write mode.
+ *
+ * Main user is sys_prctl(PR_SET_MM_MAP/EXE_FILE).
+ */
+int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
+{
+	struct vm_area_struct *vma;
+	struct file *old_exe_file;
+	int ret = 0;
+
+	/* Forbid mm->exe_file change if old file still mapped. */
+	old_exe_file = get_mm_exe_file(mm);
+	if (old_exe_file) {
+		VMA_ITERATOR(vmi, mm, 0);
+		mmap_read_lock(mm);
+		for_each_vma(vmi, vma) {
+			if (!vma->vm_file)
+				continue;
+			if (path_equal(&vma->vm_file->f_path,
+				       &old_exe_file->f_path)) {
+				ret = -EBUSY;
+				break;
+			}
+		}
+		mmap_read_unlock(mm);
+		fput(old_exe_file);
+		if (ret)
+			return ret;
+	}
+
+	/* set the new file, lockless */
+	ret = deny_write_access(new_exe_file);
+	if (ret)
+		return -EACCES;
+	get_file(new_exe_file);
+
+	old_exe_file = xchg(&mm->exe_file, new_exe_file);
+	if (old_exe_file) {
+		/*
+		 * Don't race with dup_mmap() getting the file and disallowing
+		 * write access while someone might open the file writable.
+		 */
+		mmap_read_lock(mm);
+		allow_write_access(old_exe_file);
+		fput(old_exe_file);
+		mmap_read_unlock(mm);
+	}
+	return 0;
+}
+
+/**
+ * get_mm_exe_file - acquire a reference to the mm's executable file
+ *
+ * Returns %NULL if mm has no associated executable file.
+ * User must release file via fput().
+ */
+struct file *get_mm_exe_file(struct mm_struct *mm)
+{
+	struct file *exe_file;
+
+	rcu_read_lock();
+	exe_file = rcu_dereference(mm->exe_file);
+	if (exe_file && !get_file_rcu(exe_file))
+		exe_file = NULL;
+	rcu_read_unlock();
+	return exe_file;
+}
+
+/**
+ * get_task_exe_file - acquire a reference to the task's executable file
+ *
+ * Returns %NULL if task's mm (if any) has no associated executable file or
+ * this is a kernel thread with borrowed mm (see the comment above get_task_mm).
+ * User must release file via fput().
+ */
+struct file *get_task_exe_file(struct task_struct *task)
+{
+	struct file *exe_file = NULL;
+	struct mm_struct *mm;
+
+	task_lock(task);
+	mm = task->mm;
+	if (mm) {
+		if (!(task->flags & PF_KTHREAD))
+			exe_file = get_mm_exe_file(mm);
+	}
+	task_unlock(task);
+	return exe_file;
+}
+
+/**
+ * get_task_mm - acquire a reference to the task's mm
+ *
+ * Returns %NULL if the task has no mm.  Checks PF_KTHREAD (meaning
+ * this kernel workthread has transiently adopted a user mm with use_mm,
+ * to do its AIO) is not set and if so returns a reference to it, after
+ * bumping up the use count.  User must release the mm via mmput()
+ * after use.  Typically used by /proc and ptrace.
+ */
+struct mm_struct *get_task_mm(struct task_struct *task)
+{
+	struct mm_struct *mm;
+
+	task_lock(task);
+	mm = task->mm;
+	if (mm) {
+		if (task->flags & PF_KTHREAD)
+			mm = NULL;
+		else
+			mmget(mm);
+	}
+	task_unlock(task);
+	return mm;
+}
+EXPORT_SYMBOL_GPL(get_task_mm);
+
+struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
+{
+	struct mm_struct *mm;
+	int err;
+
+	err =  down_read_killable(&task->signal->exec_update_lock);
+	if (err)
+		return ERR_PTR(err);
+
+	mm = get_task_mm(task);
+	if (mm && mm != current->mm &&
+			!ptrace_may_access(task, mode)) {
+		mmput(mm);
+		mm = ERR_PTR(-EACCES);
+	}
+	up_read(&task->signal->exec_update_lock);
+
+	return mm;
+}
+
+static void complete_vfork_done(struct task_struct *tsk)
+{
+	struct completion *vfork;
+
+	task_lock(tsk);
+	vfork = tsk->vfork_done;
+	if (likely(vfork)) {
+		tsk->vfork_done = NULL;
+		complete(vfork);
+	}
+	task_unlock(tsk);
+}
+
+static int wait_for_vfork_done(struct task_struct *child,
+				struct completion *vfork)
+{
+	unsigned int state = TASK_UNINTERRUPTIBLE|TASK_KILLABLE|TASK_FREEZABLE;
+	int killed;
+
+	cgroup_enter_frozen();
+	killed = wait_for_completion_state(vfork, state);
+	cgroup_leave_frozen(false);
+
+	if (killed) {
+		task_lock(child);
+		child->vfork_done = NULL;
+		task_unlock(child);
+	}
+
+	put_task_struct(child);
+	return killed;
+}
+
+/* Please note the differences between mmput and mm_release.
+ * mmput is called whenever we stop holding onto a mm_struct,
+ * error success whatever.
+ *
+ * mm_release is called after a mm_struct has been removed
+ * from the current process.
+ *
+ * This difference is important for error handling, when we
+ * only half set up a mm_struct for a new process and need to restore
+ * the old one.  Because we mmput the new mm_struct before
+ * restoring the old one. . .
+ * Eric Biederman 10 January 1998
+ */
+static void mm_release(struct task_struct *tsk, struct mm_struct *mm)
+{
+	uprobe_free_utask(tsk);
+
+	/* Get rid of any cached register state */
+	deactivate_mm(tsk, mm);
+
+	/*
+	 * Signal userspace if we're not exiting with a core dump
+	 * because we want to leave the value intact for debugging
+	 * purposes.
+	 */
+	if (tsk->clear_child_tid) {
+		if (atomic_read(&mm->mm_users) > 1) {
+			/*
+			 * We don't check the error code - if userspace has
+			 * not set up a proper pointer then tough luck.
+			 */
+			put_user(0, tsk->clear_child_tid);
+			do_futex(tsk->clear_child_tid, FUTEX_WAKE,
+					1, NULL, NULL, 0, 0);
+		}
+		tsk->clear_child_tid = NULL;
+	}
+
+	/*
+	 * All done, finally we can wake up parent and return this mm to him.
+	 * Also kthread_stop() uses this completion for synchronization.
+	 */
+	if (tsk->vfork_done)
+		complete_vfork_done(tsk);
+}
+
+void exit_mm_release(struct task_struct *tsk, struct mm_struct *mm)
+{
+	futex_exit_release(tsk);
+	mm_release(tsk, mm);
+}
+
+void exec_mm_release(struct task_struct *tsk, struct mm_struct *mm)
+{
+	futex_exec_release(tsk);
+	mm_release(tsk, mm);
+}
+
+/**
+ * dup_mm() - duplicates an existing mm structure
+ * @tsk: the task_struct with which the new mm will be associated.
+ * @oldmm: the mm to duplicate.
+ *
+ * Allocates a new mm structure and duplicates the provided @oldmm structure
+ * content into it.
+ *
+ * Return: the duplicated mm or NULL on failure.
+ */
+static struct mm_struct *dup_mm(struct task_struct *tsk,
+				struct mm_struct *oldmm)
+{
+	struct mm_struct *mm;
+	int err;
+
+	mm = allocate_mm();
+	if (!mm)
+		goto fail_nomem;
+
+	memcpy(mm, oldmm, sizeof(*mm));
+
+	if (!mm_init(mm, tsk, mm->user_ns))
+		goto fail_nomem;
+
+	err = dup_mmap(mm, oldmm);
+	if (err)
+		goto free_pt;
+
+	mm->hiwater_rss = get_mm_rss(mm);
+	mm->hiwater_vm = mm->total_vm;
+
+	if (mm->binfmt && !try_module_get(mm->binfmt->module))
+		goto free_pt;
+
+	return mm;
+
+free_pt:
+	/* don't put binfmt in mmput, we haven't got module yet */
+	mm->binfmt = NULL;
+	mm_init_owner(mm, NULL);
+	mmput(mm);
+
+fail_nomem:
+	return NULL;
+}
+
+static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
+{
+	struct mm_struct *mm, *oldmm;
+
+	tsk->min_flt = tsk->maj_flt = 0;
+	tsk->nvcsw = tsk->nivcsw = 0;
+#ifdef CONFIG_DETECT_HUNG_TASK
+	tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw;
+	tsk->last_switch_time = 0;
+#endif
+
+	tsk->mm = NULL;
+	tsk->active_mm = NULL;
+
+	/*
+	 * Are we cloning a kernel thread?
+	 *
+	 * We need to steal a active VM for that..
+	 */
+	oldmm = current->mm;
+	if (!oldmm)
+		return 0;
+
+	if (clone_flags & CLONE_VM) {
+		mmget(oldmm);
+		mm = oldmm;
+	} else {
+		mm = dup_mm(tsk, current->mm);
+		if (!mm)
+			return -ENOMEM;
+	}
+
+	tsk->mm = mm;
+	tsk->active_mm = mm;
+	return 0;
+}
+
+static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
+{
+	struct fs_struct *fs = current->fs;
+	if (clone_flags & CLONE_FS) {
+		/* tsk->fs is already what we want */
+		spin_lock(&fs->lock);
+		if (fs->in_exec) {
+			spin_unlock(&fs->lock);
+			return -EAGAIN;
+		}
+		fs->users++;
+		spin_unlock(&fs->lock);
+		return 0;
+	}
+	tsk->fs = copy_fs_struct(fs);
+	if (!tsk->fs)
+		return -ENOMEM;
+	return 0;
+}
+
+static int copy_files(unsigned long clone_flags, struct task_struct *tsk)
+{
+	struct files_struct *oldf, *newf;
+	int error = 0;
+
+	/*
+	 * A background process may not have any files ...
+	 */
+	oldf = current->files;
+	if (!oldf)
+		goto out;
+
+	if (clone_flags & CLONE_FILES) {
+		atomic_inc(&oldf->count);
+		goto out;
+	}
+
+	newf = dup_fd(oldf, NR_OPEN_MAX, &error);
+	if (!newf)
+		goto out;
+
+	tsk->files = newf;
+	error = 0;
+out:
+	return error;
+}
+
+static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
+{
+	struct sighand_struct *sig;
+
+	if (clone_flags & CLONE_SIGHAND) {
+		refcount_inc(&current->sighand->count);
+		return 0;
+	}
+	sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
+	RCU_INIT_POINTER(tsk->sighand, sig);
+	if (!sig)
+		return -ENOMEM;
+
+	refcount_set(&sig->count, 1);
+	spin_lock_irq(&current->sighand->siglock);
+	memcpy(sig->action, current->sighand->action, sizeof(sig->action));
+	spin_unlock_irq(&current->sighand->siglock);
+
+	/* Reset all signal handler not set to SIG_IGN to SIG_DFL. */
+	if (clone_flags & CLONE_CLEAR_SIGHAND)
+		flush_signal_handlers(tsk, 0);
+
+	return 0;
+}
+
+void __cleanup_sighand(struct sighand_struct *sighand)
+{
+	if (refcount_dec_and_test(&sighand->count)) {
+		signalfd_cleanup(sighand);
+		/*
+		 * sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it
+		 * without an RCU grace period, see __lock_task_sighand().
+		 */
+		kmem_cache_free(sighand_cachep, sighand);
+	}
+}
+
+/*
+ * Initialize POSIX timer handling for a thread group.
+ */
+static void posix_cpu_timers_init_group(struct signal_struct *sig)
+{
+	struct posix_cputimers *pct = &sig->posix_cputimers;
+	unsigned long cpu_limit;
+
+	cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
+	posix_cputimers_group_init(pct, cpu_limit);
+}
+
+static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
+{
+	struct signal_struct *sig;
+
+	if (clone_flags & CLONE_THREAD)
+		return 0;
+
+	sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL);
+	tsk->signal = sig;
+	if (!sig)
+		return -ENOMEM;
+
+	sig->nr_threads = 1;
+	sig->quick_threads = 1;
+	atomic_set(&sig->live, 1);
+	refcount_set(&sig->sigcnt, 1);
+
+	/* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */
+	sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node);
+	tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head);
+
+	init_waitqueue_head(&sig->wait_chldexit);
+	sig->curr_target = tsk;
+	init_sigpending(&sig->shared_pending);
+	INIT_HLIST_HEAD(&sig->multiprocess);
+	seqlock_init(&sig->stats_lock);
+	prev_cputime_init(&sig->prev_cputime);
+
+#ifdef CONFIG_POSIX_TIMERS
+	INIT_LIST_HEAD(&sig->posix_timers);
+	hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	sig->real_timer.function = it_real_fn;
+#endif
+
+	task_lock(current->group_leader);
+	memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
+	task_unlock(current->group_leader);
+
+	posix_cpu_timers_init_group(sig);
+
+	tty_audit_fork(sig);
+	sched_autogroup_fork(sig);
+
+	sig->oom_score_adj = current->signal->oom_score_adj;
+	sig->oom_score_adj_min = current->signal->oom_score_adj_min;
+
+	mutex_init(&sig->cred_guard_mutex);
+	init_rwsem(&sig->exec_update_lock);
+
+	return 0;
+}
+
+static void copy_seccomp(struct task_struct *p)
+{
+#ifdef CONFIG_SECCOMP
+	/*
+	 * Must be called with sighand->lock held, which is common to
+	 * all threads in the group. Holding cred_guard_mutex is not
+	 * needed because this new task is not yet running and cannot
+	 * be racing exec.
+	 */
+	assert_spin_locked(&current->sighand->siglock);
+
+	/* Ref-count the new filter user, and assign it. */
+	get_seccomp_filter(current);
+	p->seccomp = current->seccomp;
+
+	/*
+	 * Explicitly enable no_new_privs here in case it got set
+	 * between the task_struct being duplicated and holding the
+	 * sighand lock. The seccomp state and nnp must be in sync.
+	 */
+	if (task_no_new_privs(current))
+		task_set_no_new_privs(p);
+
+	/*
+	 * If the parent gained a seccomp mode after copying thread
+	 * flags and between before we held the sighand lock, we have
+	 * to manually enable the seccomp thread flag here.
+	 */
+	if (p->seccomp.mode != SECCOMP_MODE_DISABLED)
+		set_task_syscall_work(p, SECCOMP);
+#endif
+}
+
+SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr)
+{
+	current->clear_child_tid = tidptr;
+
+	return task_pid_vnr(current);
+}
+
+static void rt_mutex_init_task(struct task_struct *p)
+{
+	raw_spin_lock_init(&p->pi_lock);
+#ifdef CONFIG_RT_MUTEXES
+	p->pi_waiters = RB_ROOT_CACHED;
+	p->pi_top_task = NULL;
+	p->pi_blocked_on = NULL;
+#endif
+}
+
+static inline void init_task_pid_links(struct task_struct *task)
+{
+	enum pid_type type;
+
+	for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type)
+		INIT_HLIST_NODE(&task->pid_links[type]);
+}
+
+static inline void
+init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid)
+{
+	if (type == PIDTYPE_PID)
+		task->thread_pid = pid;
+	else
+		task->signal->pids[type] = pid;
+}
+
+static inline void rcu_copy_process(struct task_struct *p)
+{
+#ifdef CONFIG_PREEMPT_RCU
+	p->rcu_read_lock_nesting = 0;
+	p->rcu_read_unlock_special.s = 0;
+	p->rcu_blocked_node = NULL;
+	INIT_LIST_HEAD(&p->rcu_node_entry);
+#endif /* #ifdef CONFIG_PREEMPT_RCU */
+#ifdef CONFIG_TASKS_RCU
+	p->rcu_tasks_holdout = false;
+	INIT_LIST_HEAD(&p->rcu_tasks_holdout_list);
+	p->rcu_tasks_idle_cpu = -1;
+#endif /* #ifdef CONFIG_TASKS_RCU */
+#ifdef CONFIG_TASKS_TRACE_RCU
+	p->trc_reader_nesting = 0;
+	p->trc_reader_special.s = 0;
+	INIT_LIST_HEAD(&p->trc_holdout_list);
+	INIT_LIST_HEAD(&p->trc_blkd_node);
+#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
+}
+
+struct pid *pidfd_pid(const struct file *file)
+{
+	if (file->f_op == &pidfd_fops)
+		return file->private_data;
+
+	return ERR_PTR(-EBADF);
+}
+
+static int pidfd_release(struct inode *inode, struct file *file)
+{
+	struct pid *pid = file->private_data;
+
+	file->private_data = NULL;
+	put_pid(pid);
+	return 0;
+}
+
+#ifdef CONFIG_PROC_FS
+/**
+ * pidfd_show_fdinfo - print information about a pidfd
+ * @m: proc fdinfo file
+ * @f: file referencing a pidfd
+ *
+ * Pid:
+ * This function will print the pid that a given pidfd refers to in the
+ * pid namespace of the procfs instance.
+ * If the pid namespace of the process is not a descendant of the pid
+ * namespace of the procfs instance 0 will be shown as its pid. This is
+ * similar to calling getppid() on a process whose parent is outside of
+ * its pid namespace.
+ *
+ * NSpid:
+ * If pid namespaces are supported then this function will also print
+ * the pid of a given pidfd refers to for all descendant pid namespaces
+ * starting from the current pid namespace of the instance, i.e. the
+ * Pid field and the first entry in the NSpid field will be identical.
+ * If the pid namespace of the process is not a descendant of the pid
+ * namespace of the procfs instance 0 will be shown as its first NSpid
+ * entry and no others will be shown.
+ * Note that this differs from the Pid and NSpid fields in
+ * /proc/<pid>/status where Pid and NSpid are always shown relative to
+ * the  pid namespace of the procfs instance. The difference becomes
+ * obvious when sending around a pidfd between pid namespaces from a
+ * different branch of the tree, i.e. where no ancestral relation is
+ * present between the pid namespaces:
+ * - create two new pid namespaces ns1 and ns2 in the initial pid
+ *   namespace (also take care to create new mount namespaces in the
+ *   new pid namespace and mount procfs)
+ * - create a process with a pidfd in ns1
+ * - send pidfd from ns1 to ns2
+ * - read /proc/self/fdinfo/<pidfd> and observe that both Pid and NSpid
+ *   have exactly one entry, which is 0
+ */
+static void pidfd_show_fdinfo(struct seq_file *m, struct file *f)
+{
+	struct pid *pid = f->private_data;
+	struct pid_namespace *ns;
+	pid_t nr = -1;
+
+	if (likely(pid_has_task(pid, PIDTYPE_PID))) {
+		ns = proc_pid_ns(file_inode(m->file)->i_sb);
+		nr = pid_nr_ns(pid, ns);
+	}
+
+	seq_put_decimal_ll(m, "Pid:\t", nr);
+
+#ifdef CONFIG_PID_NS
+	seq_put_decimal_ll(m, "\nNSpid:\t", nr);
+	if (nr > 0) {
+		int i;
+
+		/* If nr is non-zero it means that 'pid' is valid and that
+		 * ns, i.e. the pid namespace associated with the procfs
+		 * instance, is in the pid namespace hierarchy of pid.
+		 * Start at one below the already printed level.
+		 */
+		for (i = ns->level + 1; i <= pid->level; i++)
+			seq_put_decimal_ll(m, "\t", pid->numbers[i].nr);
+	}
+#endif
+	seq_putc(m, '\n');
+}
+#endif
+
+/*
+ * Poll support for process exit notification.
+ */
+static __poll_t pidfd_poll(struct file *file, struct poll_table_struct *pts)
+{
+	struct pid *pid = file->private_data;
+	__poll_t poll_flags = 0;
+
+	poll_wait(file, &pid->wait_pidfd, pts);
+
+	/*
+	 * Inform pollers only when the whole thread group exits.
+	 * If the thread group leader exits before all other threads in the
+	 * group, then poll(2) should block, similar to the wait(2) family.
+	 */
+	if (thread_group_exited(pid))
+		poll_flags = EPOLLIN | EPOLLRDNORM;
+
+	return poll_flags;
+}
+
+const struct file_operations pidfd_fops = {
+	.release = pidfd_release,
+	.poll = pidfd_poll,
+#ifdef CONFIG_PROC_FS
+	.show_fdinfo = pidfd_show_fdinfo,
+#endif
+};
+
+static void __delayed_free_task(struct rcu_head *rhp)
+{
+	struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
+
+	free_task(tsk);
+}
+
+static __always_inline void delayed_free_task(struct task_struct *tsk)
+{
+	if (IS_ENABLED(CONFIG_MEMCG))
+		call_rcu(&tsk->rcu, __delayed_free_task);
+	else
+		free_task(tsk);
+}
+
+static void copy_oom_score_adj(u64 clone_flags, struct task_struct *tsk)
+{
+	/* Skip if kernel thread */
+	if (!tsk->mm)
+		return;
+
+	/* Skip if spawning a thread or using vfork */
+	if ((clone_flags & (CLONE_VM | CLONE_THREAD | CLONE_VFORK)) != CLONE_VM)
+		return;
+
+	/* We need to synchronize with __set_oom_adj */
+	mutex_lock(&oom_adj_mutex);
+	set_bit(MMF_MULTIPROCESS, &tsk->mm->flags);
+	/* Update the values in case they were changed after copy_signal */
+	tsk->signal->oom_score_adj = current->signal->oom_score_adj;
+	tsk->signal->oom_score_adj_min = current->signal->oom_score_adj_min;
+	mutex_unlock(&oom_adj_mutex);
+}
+
+#ifdef CONFIG_RV
+static void rv_task_fork(struct task_struct *p)
+{
+	int i;
+
+	for (i = 0; i < RV_PER_TASK_MONITORS; i++)
+		p->rv[i].da_mon.monitoring = false;
+}
+#else
+#define rv_task_fork(p) do {} while (0)
+#endif
+
+/*
+ * This creates a new process as a copy of the old one,
+ * but does not actually start it yet.
+ *
+ * It copies the registers, and all the appropriate
+ * parts of the process environment (as per the clone
+ * flags). The actual kick-off is left to the caller.
+ */
+static __latent_entropy struct task_struct *copy_process(
+					struct pid *pid,
+					int trace,
+					int node,
+					struct kernel_clone_args *args)
+{
+	int pidfd = -1, retval;
+	struct task_struct *p;
+	struct multiprocess_signals delayed;
+	struct file *pidfile = NULL;
+	const u64 clone_flags = args->flags;
+	struct nsproxy *nsp = current->nsproxy;
+
+	/*
+	 * Don't allow sharing the root directory with processes in a different
+	 * namespace
+	 */
+	if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
+		return ERR_PTR(-EINVAL);
+
+	if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS))
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * Thread groups must share signals as well, and detached threads
+	 * can only be started up within the thread group.
+	 */
+	if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * Shared signal handlers imply shared VM. By way of the above,
+	 * thread groups also imply shared VM. Blocking this case allows
+	 * for various simplifications in other code.
+	 */
+	if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * Siblings of global init remain as zombies on exit since they are
+	 * not reaped by their parent (swapper). To solve this and to avoid
+	 * multi-rooted process trees, prevent global and container-inits
+	 * from creating siblings.
+	 */
+	if ((clone_flags & CLONE_PARENT) &&
+				current->signal->flags & SIGNAL_UNKILLABLE)
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * If the new process will be in a different pid or user namespace
+	 * do not allow it to share a thread group with the forking task.
+	 */
+	if (clone_flags & CLONE_THREAD) {
+		if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) ||
+		    (task_active_pid_ns(current) != nsp->pid_ns_for_children))
+			return ERR_PTR(-EINVAL);
+	}
+
+	/*
+	 * If the new process will be in a different time namespace
+	 * do not allow it to share VM or a thread group with the forking task.
+	 */
+	if (clone_flags & (CLONE_THREAD | CLONE_VM)) {
+		if (nsp->time_ns != nsp->time_ns_for_children)
+			return ERR_PTR(-EINVAL);
+	}
+
+	if (clone_flags & CLONE_PIDFD) {
+		/*
+		 * - CLONE_DETACHED is blocked so that we can potentially
+		 *   reuse it later for CLONE_PIDFD.
+		 * - CLONE_THREAD is blocked until someone really needs it.
+		 */
+		if (clone_flags & (CLONE_DETACHED | CLONE_THREAD))
+			return ERR_PTR(-EINVAL);
+	}
+
+	/*
+	 * Force any signals received before this point to be delivered
+	 * before the fork happens.  Collect up signals sent to multiple
+	 * processes that happen during the fork and delay them so that
+	 * they appear to happen after the fork.
+	 */
+	sigemptyset(&delayed.signal);
+	INIT_HLIST_NODE(&delayed.node);
+
+	spin_lock_irq(&current->sighand->siglock);
+	if (!(clone_flags & CLONE_THREAD))
+		hlist_add_head(&delayed.node, &current->signal->multiprocess);
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+	retval = -ERESTARTNOINTR;
+	if (task_sigpending(current))
+		goto fork_out;
+
+	retval = -ENOMEM;
+	p = dup_task_struct(current, node);
+	if (!p)
+		goto fork_out;
+	p->flags &= ~PF_KTHREAD;
+	if (args->kthread)
+		p->flags |= PF_KTHREAD;
+	if (args->io_thread) {
+		/*
+		 * Mark us an IO worker, and block any signal that isn't
+		 * fatal or STOP
+		 */
+		p->flags |= PF_IO_WORKER;
+		siginitsetinv(&p->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP));
+	}
+
+	p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? args->child_tid : NULL;
+	/*
+	 * Clear TID on mm_release()?
+	 */
+	p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? args->child_tid : NULL;
+
+	ftrace_graph_init_task(p);
+
+	rt_mutex_init_task(p);
+
+	lockdep_assert_irqs_enabled();
+#ifdef CONFIG_PROVE_LOCKING
+	DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
+#endif
+	retval = copy_creds(p, clone_flags);
+	if (retval < 0)
+		goto bad_fork_free;
+
+	retval = -EAGAIN;
+	if (is_rlimit_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) {
+		if (p->real_cred->user != INIT_USER &&
+		    !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
+			goto bad_fork_cleanup_count;
+	}
+	current->flags &= ~PF_NPROC_EXCEEDED;
+
+	/*
+	 * If multiple threads are within copy_process(), then this check
+	 * triggers too late. This doesn't hurt, the check is only there
+	 * to stop root fork bombs.
+	 */
+	retval = -EAGAIN;
+	if (data_race(nr_threads >= max_threads))
+		goto bad_fork_cleanup_count;
+
+	delayacct_tsk_init(p);	/* Must remain after dup_task_struct() */
+	p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE | PF_NO_SETAFFINITY);
+	p->flags |= PF_FORKNOEXEC;
+	INIT_LIST_HEAD(&p->children);
+	INIT_LIST_HEAD(&p->sibling);
+	rcu_copy_process(p);
+	p->vfork_done = NULL;
+	spin_lock_init(&p->alloc_lock);
+
+	init_sigpending(&p->pending);
+
+	p->utime = p->stime = p->gtime = 0;
+#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
+	p->utimescaled = p->stimescaled = 0;
+#endif
+	prev_cputime_init(&p->prev_cputime);
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+	seqcount_init(&p->vtime.seqcount);
+	p->vtime.starttime = 0;
+	p->vtime.state = VTIME_INACTIVE;
+#endif
+
+#ifdef CONFIG_IO_URING
+	p->io_uring = NULL;
+#endif
+
+#if defined(SPLIT_RSS_COUNTING)
+	memset(&p->rss_stat, 0, sizeof(p->rss_stat));
+#endif
+
+	p->default_timer_slack_ns = current->timer_slack_ns;
+
+#ifdef CONFIG_PSI
+	p->psi_flags = 0;
+#endif
+
+	task_io_accounting_init(&p->ioac);
+	acct_clear_integrals(p);
+
+	posix_cputimers_init(&p->posix_cputimers);
+
+	p->io_context = NULL;
+	audit_set_context(p, NULL);
+	cgroup_fork(p);
+	if (args->kthread) {
+		if (!set_kthread_struct(p))
+			goto bad_fork_cleanup_delayacct;
+	}
+#ifdef CONFIG_NUMA
+	p->mempolicy = mpol_dup(p->mempolicy);
+	if (IS_ERR(p->mempolicy)) {
+		retval = PTR_ERR(p->mempolicy);
+		p->mempolicy = NULL;
+		goto bad_fork_cleanup_delayacct;
+	}
+#endif
+#ifdef CONFIG_CPUSETS
+	p->cpuset_mem_spread_rotor = NUMA_NO_NODE;
+	p->cpuset_slab_spread_rotor = NUMA_NO_NODE;
+	seqcount_spinlock_init(&p->mems_allowed_seq, &p->alloc_lock);
+#endif
+#ifdef CONFIG_TRACE_IRQFLAGS
+	memset(&p->irqtrace, 0, sizeof(p->irqtrace));
+	p->irqtrace.hardirq_disable_ip	= _THIS_IP_;
+	p->irqtrace.softirq_enable_ip	= _THIS_IP_;
+	p->softirqs_enabled		= 1;
+	p->softirq_context		= 0;
+#endif
+
+	p->pagefault_disabled = 0;
+
+#ifdef CONFIG_LOCKDEP
+	lockdep_init_task(p);
+#endif
+
+#ifdef CONFIG_DEBUG_MUTEXES
+	p->blocked_on = NULL; /* not blocked yet */
+#endif
+#ifdef CONFIG_BCACHE
+	p->sequential_io	= 0;
+	p->sequential_io_avg	= 0;
+#endif
+#ifdef CONFIG_BPF_SYSCALL
+	RCU_INIT_POINTER(p->bpf_storage, NULL);
+	p->bpf_ctx = NULL;
+#endif
+
+	/* Perform scheduler related setup. Assign this task to a CPU. */
+	retval = sched_fork(clone_flags, p);
+	if (retval)
+		goto bad_fork_cleanup_policy;
+
+	retval = perf_event_init_task(p, clone_flags);
+	if (retval)
+		goto bad_fork_cleanup_policy;
+	retval = audit_alloc(p);
+	if (retval)
+		goto bad_fork_cleanup_perf;
+	/* copy all the process information */
+	shm_init_task(p);
+	retval = security_task_alloc(p, clone_flags);
+	if (retval)
+		goto bad_fork_cleanup_audit;
+	retval = copy_semundo(clone_flags, p);
+	if (retval)
+		goto bad_fork_cleanup_security;
+	retval = copy_files(clone_flags, p);
+	if (retval)
+		goto bad_fork_cleanup_semundo;
+	retval = copy_fs(clone_flags, p);
+	if (retval)
+		goto bad_fork_cleanup_files;
+	retval = copy_sighand(clone_flags, p);
+	if (retval)
+		goto bad_fork_cleanup_fs;
+	retval = copy_signal(clone_flags, p);
+	if (retval)
+		goto bad_fork_cleanup_sighand;
+	retval = copy_mm(clone_flags, p);
+	if (retval)
+		goto bad_fork_cleanup_signal;
+	retval = copy_namespaces(clone_flags, p);
+	if (retval)
+		goto bad_fork_cleanup_mm;
+	retval = copy_io(clone_flags, p);
+	if (retval)
+		goto bad_fork_cleanup_namespaces;
+	retval = copy_thread(p, args);
+	if (retval)
+		goto bad_fork_cleanup_io;
+
+	stackleak_task_init(p);
+
+	if (pid != &init_struct_pid) {
+		pid = alloc_pid(p->nsproxy->pid_ns_for_children, args->set_tid,
+				args->set_tid_size);
+		if (IS_ERR(pid)) {
+			retval = PTR_ERR(pid);
+			goto bad_fork_cleanup_thread;
+		}
+	}
+
+	/*
+	 * This has to happen after we've potentially unshared the file
+	 * descriptor table (so that the pidfd doesn't leak into the child
+	 * if the fd table isn't shared).
+	 */
+	if (clone_flags & CLONE_PIDFD) {
+		retval = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
+		if (retval < 0)
+			goto bad_fork_free_pid;
+
+		pidfd = retval;
+
+		pidfile = anon_inode_getfile("[pidfd]", &pidfd_fops, pid,
+					      O_RDWR | O_CLOEXEC);
+		if (IS_ERR(pidfile)) {
+			put_unused_fd(pidfd);
+			retval = PTR_ERR(pidfile);
+			goto bad_fork_free_pid;
+		}
+		get_pid(pid);	/* held by pidfile now */
+
+		retval = put_user(pidfd, args->pidfd);
+		if (retval)
+			goto bad_fork_put_pidfd;
+	}
+
+#ifdef CONFIG_BLOCK
+	p->plug = NULL;
+#endif
+	futex_init_task(p);
+
+	/*
+	 * sigaltstack should be cleared when sharing the same VM
+	 */
+	if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
+		sas_ss_reset(p);
+
+	/*
+	 * Syscall tracing and stepping should be turned off in the
+	 * child regardless of CLONE_PTRACE.
+	 */
+	user_disable_single_step(p);
+	clear_task_syscall_work(p, SYSCALL_TRACE);
+#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
+	clear_task_syscall_work(p, SYSCALL_EMU);
+#endif
+	clear_tsk_latency_tracing(p);
+
+	/* ok, now we should be set up.. */
+	p->pid = pid_nr(pid);
+	if (clone_flags & CLONE_THREAD) {
+		p->group_leader = current->group_leader;
+		p->tgid = current->tgid;
+	} else {
+		p->group_leader = p;
+		p->tgid = p->pid;
+	}
+
+	p->nr_dirtied = 0;
+	p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10);
+	p->dirty_paused_when = 0;
+
+	p->pdeath_signal = 0;
+	INIT_LIST_HEAD(&p->thread_group);
+	p->task_works = NULL;
+	clear_posix_cputimers_work(p);
+
+#ifdef CONFIG_KRETPROBES
+	p->kretprobe_instances.first = NULL;
+#endif
+#ifdef CONFIG_RETHOOK
+	p->rethooks.first = NULL;
+#endif
+
+	/*
+	 * Ensure that the cgroup subsystem policies allow the new process to be
+	 * forked. It should be noted that the new process's css_set can be changed
+	 * between here and cgroup_post_fork() if an organisation operation is in
+	 * progress.
+	 */
+	retval = cgroup_can_fork(p, args);
+	if (retval)
+		goto bad_fork_put_pidfd;
+
+	/*
+	 * Now that the cgroups are pinned, re-clone the parent cgroup and put
+	 * the new task on the correct runqueue. All this *before* the task
+	 * becomes visible.
+	 *
+	 * This isn't part of ->can_fork() because while the re-cloning is
+	 * cgroup specific, it unconditionally needs to place the task on a
+	 * runqueue.
+	 */
+	sched_cgroup_fork(p, args);
+
+	/*
+	 * From this point on we must avoid any synchronous user-space
+	 * communication until we take the tasklist-lock. In particular, we do
+	 * not want user-space to be able to predict the process start-time by
+	 * stalling fork(2) after we recorded the start_time but before it is
+	 * visible to the system.
+	 */
+
+	p->start_time = ktime_get_ns();
+	p->start_boottime = ktime_get_boottime_ns();
+
+	/*
+	 * Make it visible to the rest of the system, but dont wake it up yet.
+	 * Need tasklist lock for parent etc handling!
+	 */
+	write_lock_irq(&tasklist_lock);
+
+	/* CLONE_PARENT re-uses the old parent */
+	if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
+		p->real_parent = current->real_parent;
+		p->parent_exec_id = current->parent_exec_id;
+		if (clone_flags & CLONE_THREAD)
+			p->exit_signal = -1;
+		else
+			p->exit_signal = current->group_leader->exit_signal;
+	} else {
+		p->real_parent = current;
+		p->parent_exec_id = current->self_exec_id;
+		p->exit_signal = args->exit_signal;
+	}
+
+	klp_copy_process(p);
+
+	sched_core_fork(p);
+
+	spin_lock(&current->sighand->siglock);
+
+	rv_task_fork(p);
+
+	rseq_fork(p, clone_flags);
+
+	/* Don't start children in a dying pid namespace */
+	if (unlikely(!(ns_of_pid(pid)->pid_allocated & PIDNS_ADDING))) {
+		retval = -ENOMEM;
+		goto bad_fork_cancel_cgroup;
+	}
+
+	/* Let kill terminate clone/fork in the middle */
+	if (fatal_signal_pending(current)) {
+		retval = -EINTR;
+		goto bad_fork_cancel_cgroup;
+	}
+
+	/* No more failure paths after this point. */
+
+	/*
+	 * Copy seccomp details explicitly here, in case they were changed
+	 * before holding sighand lock.
+	 */
+	copy_seccomp(p);
+
+	init_task_pid_links(p);
+	if (likely(p->pid)) {
+		ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);
+
+		init_task_pid(p, PIDTYPE_PID, pid);
+		if (thread_group_leader(p)) {
+			init_task_pid(p, PIDTYPE_TGID, pid);
+			init_task_pid(p, PIDTYPE_PGID, task_pgrp(current));
+			init_task_pid(p, PIDTYPE_SID, task_session(current));
+
+			if (is_child_reaper(pid)) {
+				ns_of_pid(pid)->child_reaper = p;
+				p->signal->flags |= SIGNAL_UNKILLABLE;
+			}
+			p->signal->shared_pending.signal = delayed.signal;
+			p->signal->tty = tty_kref_get(current->signal->tty);
+			/*
+			 * Inherit has_child_subreaper flag under the same
+			 * tasklist_lock with adding child to the process tree
+			 * for propagate_has_child_subreaper optimization.
+			 */
+			p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper ||
+							 p->real_parent->signal->is_child_subreaper;
+			list_add_tail(&p->sibling, &p->real_parent->children);
+			list_add_tail_rcu(&p->tasks, &init_task.tasks);
+			attach_pid(p, PIDTYPE_TGID);
+			attach_pid(p, PIDTYPE_PGID);
+			attach_pid(p, PIDTYPE_SID);
+			__this_cpu_inc(process_counts);
+		} else {
+			current->signal->nr_threads++;
+			current->signal->quick_threads++;
+			atomic_inc(&current->signal->live);
+			refcount_inc(&current->signal->sigcnt);
+			task_join_group_stop(p);
+			list_add_tail_rcu(&p->thread_group,
+					  &p->group_leader->thread_group);
+			list_add_tail_rcu(&p->thread_node,
+					  &p->signal->thread_head);
+		}
+		attach_pid(p, PIDTYPE_PID);
+		nr_threads++;
+	}
+	total_forks++;
+	hlist_del_init(&delayed.node);
+	spin_unlock(&current->sighand->siglock);
+	syscall_tracepoint_update(p);
+	write_unlock_irq(&tasklist_lock);
+
+	if (pidfile)
+		fd_install(pidfd, pidfile);
+
+	proc_fork_connector(p);
+	sched_post_fork(p);
+	cgroup_post_fork(p, args);
+	perf_event_fork(p);
+
+	trace_task_newtask(p, clone_flags);
+	uprobe_copy_process(p, clone_flags);
+
+	copy_oom_score_adj(clone_flags, p);
+
+	return p;
+
+bad_fork_cancel_cgroup:
+	sched_core_free(p);
+	spin_unlock(&current->sighand->siglock);
+	write_unlock_irq(&tasklist_lock);
+	cgroup_cancel_fork(p, args);
+bad_fork_put_pidfd:
+	if (clone_flags & CLONE_PIDFD) {
+		fput(pidfile);
+		put_unused_fd(pidfd);
+	}
+bad_fork_free_pid:
+	if (pid != &init_struct_pid)
+		free_pid(pid);
+bad_fork_cleanup_thread:
+	exit_thread(p);
+bad_fork_cleanup_io:
+	if (p->io_context)
+		exit_io_context(p);
+bad_fork_cleanup_namespaces:
+	exit_task_namespaces(p);
+bad_fork_cleanup_mm:
+	if (p->mm) {
+		mm_clear_owner(p->mm, p);
+		mmput(p->mm);
+	}
+bad_fork_cleanup_signal:
+	if (!(clone_flags & CLONE_THREAD))
+		free_signal_struct(p->signal);
+bad_fork_cleanup_sighand:
+	__cleanup_sighand(p->sighand);
+bad_fork_cleanup_fs:
+	exit_fs(p); /* blocking */
+bad_fork_cleanup_files:
+	exit_files(p); /* blocking */
+bad_fork_cleanup_semundo:
+	exit_sem(p);
+bad_fork_cleanup_security:
+	security_task_free(p);
+bad_fork_cleanup_audit:
+	audit_free(p);
+bad_fork_cleanup_perf:
+	perf_event_free_task(p);
+bad_fork_cleanup_policy:
+	lockdep_free_task(p);
+#ifdef CONFIG_NUMA
+	mpol_put(p->mempolicy);
+#endif
+bad_fork_cleanup_delayacct:
+	delayacct_tsk_free(p);
+bad_fork_cleanup_count:
+	dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
+	exit_creds(p);
+bad_fork_free:
+	WRITE_ONCE(p->__state, TASK_DEAD);
+	exit_task_stack_account(p);
+	put_task_stack(p);
+	delayed_free_task(p);
+fork_out:
+	spin_lock_irq(&current->sighand->siglock);
+	hlist_del_init(&delayed.node);
+	spin_unlock_irq(&current->sighand->siglock);
+	return ERR_PTR(retval);
+}
+
+static inline void init_idle_pids(struct task_struct *idle)
+{
+	enum pid_type type;
+
+	for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) {
+		INIT_HLIST_NODE(&idle->pid_links[type]); /* not really needed */
+		init_task_pid(idle, type, &init_struct_pid);
+	}
+}
+
+static int idle_dummy(void *dummy)
+{
+	/* This function is never called */
+	return 0;
+}
+
+struct task_struct * __init fork_idle(int cpu)
+{
+	struct task_struct *task;
+	struct kernel_clone_args args = {
+		.flags		= CLONE_VM,
+		.fn		= &idle_dummy,
+		.fn_arg		= NULL,
+		.kthread	= 1,
+		.idle		= 1,
+	};
+
+	task = copy_process(&init_struct_pid, 0, cpu_to_node(cpu), &args);
+	if (!IS_ERR(task)) {
+		init_idle_pids(task);
+		init_idle(task, cpu);
+	}
+
+	return task;
+}
+
+/*
+ * This is like kernel_clone(), but shaved down and tailored to just
+ * creating io_uring workers. It returns a created task, or an error pointer.
+ * The returned task is inactive, and the caller must fire it up through
+ * wake_up_new_task(p). All signals are blocked in the created task.
+ */
+struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node)
+{
+	unsigned long flags = CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|
+				CLONE_IO;
+	struct kernel_clone_args args = {
+		.flags		= ((lower_32_bits(flags) | CLONE_VM |
+				    CLONE_UNTRACED) & ~CSIGNAL),
+		.exit_signal	= (lower_32_bits(flags) & CSIGNAL),
+		.fn		= fn,
+		.fn_arg		= arg,
+		.io_thread	= 1,
+	};
+
+	return copy_process(NULL, 0, node, &args);
+}
+
+/*
+ *  Ok, this is the main fork-routine.
+ *
+ * It copies the process, and if successful kick-starts
+ * it and waits for it to finish using the VM if required.
+ *
+ * args->exit_signal is expected to be checked for sanity by the caller.
+ */
+pid_t kernel_clone(struct kernel_clone_args *args)
+{
+	u64 clone_flags = args->flags;
+	struct completion vfork;
+	struct pid *pid;
+	struct task_struct *p;
+	int trace = 0;
+	pid_t nr;
+
+	/*
+	 * For legacy clone() calls, CLONE_PIDFD uses the parent_tid argument
+	 * to return the pidfd. Hence, CLONE_PIDFD and CLONE_PARENT_SETTID are
+	 * mutually exclusive. With clone3() CLONE_PIDFD has grown a separate
+	 * field in struct clone_args and it still doesn't make sense to have
+	 * them both point at the same memory location. Performing this check
+	 * here has the advantage that we don't need to have a separate helper
+	 * to check for legacy clone().
+	 */
+	if ((args->flags & CLONE_PIDFD) &&
+	    (args->flags & CLONE_PARENT_SETTID) &&
+	    (args->pidfd == args->parent_tid))
+		return -EINVAL;
+
+	/*
+	 * Determine whether and which event to report to ptracer.  When
+	 * called from kernel_thread or CLONE_UNTRACED is explicitly
+	 * requested, no event is reported; otherwise, report if the event
+	 * for the type of forking is enabled.
+	 */
+	if (!(clone_flags & CLONE_UNTRACED)) {
+		if (clone_flags & CLONE_VFORK)
+			trace = PTRACE_EVENT_VFORK;
+		else if (args->exit_signal != SIGCHLD)
+			trace = PTRACE_EVENT_CLONE;
+		else
+			trace = PTRACE_EVENT_FORK;
+
+		if (likely(!ptrace_event_enabled(current, trace)))
+			trace = 0;
+	}
+
+	p = copy_process(NULL, trace, NUMA_NO_NODE, args);
+	add_latent_entropy();
+
+	if (IS_ERR(p))
+		return PTR_ERR(p);
+
+	/*
+	 * Do this prior waking up the new thread - the thread pointer
+	 * might get invalid after that point, if the thread exits quickly.
+	 */
+	trace_sched_process_fork(current, p);
+
+	pid = get_task_pid(p, PIDTYPE_PID);
+	nr = pid_vnr(pid);
+
+	if (clone_flags & CLONE_PARENT_SETTID)
+		put_user(nr, args->parent_tid);
+
+	if (clone_flags & CLONE_VFORK) {
+		p->vfork_done = &vfork;
+		init_completion(&vfork);
+		get_task_struct(p);
+	}
+
+	if (IS_ENABLED(CONFIG_LRU_GEN) && !(clone_flags & CLONE_VM)) {
+		/* lock the task to synchronize with memcg migration */
+		task_lock(p);
+		lru_gen_add_mm(p->mm);
+		task_unlock(p);
+	}
+
+	wake_up_new_task(p);
+
+	/* forking complete and child started to run, tell ptracer */
+	if (unlikely(trace))
+		ptrace_event_pid(trace, pid);
+
+	if (clone_flags & CLONE_VFORK) {
+		if (!wait_for_vfork_done(p, &vfork))
+			ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid);
+	}
+
+	put_pid(pid);
+	return nr;
+}
+
+/*
+ * Create a kernel thread.
+ */
+pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
+{
+	struct kernel_clone_args args = {
+		.flags		= ((lower_32_bits(flags) | CLONE_VM |
+				    CLONE_UNTRACED) & ~CSIGNAL),
+		.exit_signal	= (lower_32_bits(flags) & CSIGNAL),
+		.fn		= fn,
+		.fn_arg		= arg,
+		.kthread	= 1,
+	};
+
+	return kernel_clone(&args);
+}
+
+/*
+ * Create a user mode thread.
+ */
+pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags)
+{
+	struct kernel_clone_args args = {
+		.flags		= ((lower_32_bits(flags) | CLONE_VM |
+				    CLONE_UNTRACED) & ~CSIGNAL),
+		.exit_signal	= (lower_32_bits(flags) & CSIGNAL),
+		.fn		= fn,
+		.fn_arg		= arg,
+	};
+
+	return kernel_clone(&args);
+}
+
+#ifdef __ARCH_WANT_SYS_FORK
+SYSCALL_DEFINE0(fork)
+{
+#ifdef CONFIG_MMU
+	struct kernel_clone_args args = {
+		.exit_signal = SIGCHLD,
+	};
+
+	return kernel_clone(&args);
+#else
+	/* can not support in nommu mode */
+	return -EINVAL;
+#endif
+}
+#endif
+
+#ifdef __ARCH_WANT_SYS_VFORK
+SYSCALL_DEFINE0(vfork)
+{
+	struct kernel_clone_args args = {
+		.flags		= CLONE_VFORK | CLONE_VM,
+		.exit_signal	= SIGCHLD,
+	};
+
+	return kernel_clone(&args);
+}
+#endif
+
+#ifdef __ARCH_WANT_SYS_CLONE
+#ifdef CONFIG_CLONE_BACKWARDS
+SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
+		 int __user *, parent_tidptr,
+		 unsigned long, tls,
+		 int __user *, child_tidptr)
+#elif defined(CONFIG_CLONE_BACKWARDS2)
+SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned long, clone_flags,
+		 int __user *, parent_tidptr,
+		 int __user *, child_tidptr,
+		 unsigned long, tls)
+#elif defined(CONFIG_CLONE_BACKWARDS3)
+SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp,
+		int, stack_size,
+		int __user *, parent_tidptr,
+		int __user *, child_tidptr,
+		unsigned long, tls)
+#else
+SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
+		 int __user *, parent_tidptr,
+		 int __user *, child_tidptr,
+		 unsigned long, tls)
+#endif
+{
+	struct kernel_clone_args args = {
+		.flags		= (lower_32_bits(clone_flags) & ~CSIGNAL),
+		.pidfd		= parent_tidptr,
+		.child_tid	= child_tidptr,
+		.parent_tid	= parent_tidptr,
+		.exit_signal	= (lower_32_bits(clone_flags) & CSIGNAL),
+		.stack		= newsp,
+		.tls		= tls,
+	};
+
+	return kernel_clone(&args);
+}
+#endif
+
+#ifdef __ARCH_WANT_SYS_CLONE3
+
+noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
+					      struct clone_args __user *uargs,
+					      size_t usize)
+{
+	int err;
+	struct clone_args args;
+	pid_t *kset_tid = kargs->set_tid;
+
+	BUILD_BUG_ON(offsetofend(struct clone_args, tls) !=
+		     CLONE_ARGS_SIZE_VER0);
+	BUILD_BUG_ON(offsetofend(struct clone_args, set_tid_size) !=
+		     CLONE_ARGS_SIZE_VER1);
+	BUILD_BUG_ON(offsetofend(struct clone_args, cgroup) !=
+		     CLONE_ARGS_SIZE_VER2);
+	BUILD_BUG_ON(sizeof(struct clone_args) != CLONE_ARGS_SIZE_VER2);
+
+	if (unlikely(usize > PAGE_SIZE))
+		return -E2BIG;
+	if (unlikely(usize < CLONE_ARGS_SIZE_VER0))
+		return -EINVAL;
+
+	err = copy_struct_from_user(&args, sizeof(args), uargs, usize);
+	if (err)
+		return err;
+
+	if (unlikely(args.set_tid_size > MAX_PID_NS_LEVEL))
+		return -EINVAL;
+
+	if (unlikely(!args.set_tid && args.set_tid_size > 0))
+		return -EINVAL;
+
+	if (unlikely(args.set_tid && args.set_tid_size == 0))
+		return -EINVAL;
+
+	/*
+	 * Verify that higher 32bits of exit_signal are unset and that
+	 * it is a valid signal
+	 */
+	if (unlikely((args.exit_signal & ~((u64)CSIGNAL)) ||
+		     !valid_signal(args.exit_signal)))
+		return -EINVAL;
+
+	if ((args.flags & CLONE_INTO_CGROUP) &&
+	    (args.cgroup > INT_MAX || usize < CLONE_ARGS_SIZE_VER2))
+		return -EINVAL;
+
+	*kargs = (struct kernel_clone_args){
+		.flags		= args.flags,
+		.pidfd		= u64_to_user_ptr(args.pidfd),
+		.child_tid	= u64_to_user_ptr(args.child_tid),
+		.parent_tid	= u64_to_user_ptr(args.parent_tid),
+		.exit_signal	= args.exit_signal,
+		.stack		= args.stack,
+		.stack_size	= args.stack_size,
+		.tls		= args.tls,
+		.set_tid_size	= args.set_tid_size,
+		.cgroup		= args.cgroup,
+	};
+
+	if (args.set_tid &&
+		copy_from_user(kset_tid, u64_to_user_ptr(args.set_tid),
+			(kargs->set_tid_size * sizeof(pid_t))))
+		return -EFAULT;
+
+	kargs->set_tid = kset_tid;
+
+	return 0;
+}
+
+/**
+ * clone3_stack_valid - check and prepare stack
+ * @kargs: kernel clone args
+ *
+ * Verify that the stack arguments userspace gave us are sane.
+ * In addition, set the stack direction for userspace since it's easy for us to
+ * determine.
+ */
+static inline bool clone3_stack_valid(struct kernel_clone_args *kargs)
+{
+	if (kargs->stack == 0) {
+		if (kargs->stack_size > 0)
+			return false;
+	} else {
+		if (kargs->stack_size == 0)
+			return false;
+
+		if (!access_ok((void __user *)kargs->stack, kargs->stack_size))
+			return false;
+
+#if !defined(CONFIG_STACK_GROWSUP) && !defined(CONFIG_IA64)
+		kargs->stack += kargs->stack_size;
+#endif
+	}
+
+	return true;
+}
+
+static bool clone3_args_valid(struct kernel_clone_args *kargs)
+{
+	/* Verify that no unknown flags are passed along. */
+	if (kargs->flags &
+	    ~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP))
+		return false;
+
+	/*
+	 * - make the CLONE_DETACHED bit reusable for clone3
+	 * - make the CSIGNAL bits reusable for clone3
+	 */
+	if (kargs->flags & (CLONE_DETACHED | (CSIGNAL & (~CLONE_NEWTIME))))
+		return false;
+
+	if ((kargs->flags & (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) ==
+	    (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND))
+		return false;
+
+	if ((kargs->flags & (CLONE_THREAD | CLONE_PARENT)) &&
+	    kargs->exit_signal)
+		return false;
+
+	if (!clone3_stack_valid(kargs))
+		return false;
+
+	return true;
+}
+
+/**
+ * clone3 - create a new process with specific properties
+ * @uargs: argument structure
+ * @size:  size of @uargs
+ *
+ * clone3() is the extensible successor to clone()/clone2().
+ * It takes a struct as argument that is versioned by its size.
+ *
+ * Return: On success, a positive PID for the child process.
+ *         On error, a negative errno number.
+ */
+SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size)
+{
+	int err;
+
+	struct kernel_clone_args kargs;
+	pid_t set_tid[MAX_PID_NS_LEVEL];
+
+	kargs.set_tid = set_tid;
+
+	err = copy_clone_args_from_user(&kargs, uargs, size);
+	if (err)
+		return err;
+
+	if (!clone3_args_valid(&kargs))
+		return -EINVAL;
+
+	return kernel_clone(&kargs);
+}
+#endif
+
+void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data)
+{
+	struct task_struct *leader, *parent, *child;
+	int res;
+
+	read_lock(&tasklist_lock);
+	leader = top = top->group_leader;
+down:
+	for_each_thread(leader, parent) {
+		list_for_each_entry(child, &parent->children, sibling) {
+			res = visitor(child, data);
+			if (res) {
+				if (res < 0)
+					goto out;
+				leader = child;
+				goto down;
+			}
+up:
+			;
+		}
+	}
+
+	if (leader != top) {
+		child = leader;
+		parent = child->real_parent;
+		leader = parent->group_leader;
+		goto up;
+	}
+out:
+	read_unlock(&tasklist_lock);
+}
+
+#ifndef ARCH_MIN_MMSTRUCT_ALIGN
+#define ARCH_MIN_MMSTRUCT_ALIGN 0
+#endif
+
+static void sighand_ctor(void *data)
+{
+	struct sighand_struct *sighand = data;
+
+	spin_lock_init(&sighand->siglock);
+	init_waitqueue_head(&sighand->signalfd_wqh);
+}
+
+void __init mm_cache_init(void)
+{
+	unsigned int mm_size;
+
+	/*
+	 * The mm_cpumask is located at the end of mm_struct, and is
+	 * dynamically sized based on the maximum CPU number this system
+	 * can have, taking hotplug into account (nr_cpu_ids).
+	 */
+	mm_size = sizeof(struct mm_struct) + cpumask_size();
+
+	mm_cachep = kmem_cache_create_usercopy("mm_struct",
+			mm_size, ARCH_MIN_MMSTRUCT_ALIGN,
+			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
+			offsetof(struct mm_struct, saved_auxv),
+			sizeof_field(struct mm_struct, saved_auxv),
+			NULL);
+}
+
+void __init proc_caches_init(void)
+{
+	sighand_cachep = kmem_cache_create("sighand_cache",
+			sizeof(struct sighand_struct), 0,
+			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU|
+			SLAB_ACCOUNT, sighand_ctor);
+	signal_cachep = kmem_cache_create("signal_cache",
+			sizeof(struct signal_struct), 0,
+			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
+			NULL);
+	files_cachep = kmem_cache_create("files_cache",
+			sizeof(struct files_struct), 0,
+			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
+			NULL);
+	fs_cachep = kmem_cache_create("fs_cache",
+			sizeof(struct fs_struct), 0,
+			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
+			NULL);
+
+	vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT);
+	mmap_init();
+	nsproxy_cache_init();
+}
+
+/*
+ * Check constraints on flags passed to the unshare system call.
+ */
+static int check_unshare_flags(unsigned long unshare_flags)
+{
+	if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
+				CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
+				CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET|
+				CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP|
+				CLONE_NEWTIME))
+		return -EINVAL;
+	/*
+	 * Not implemented, but pretend it works if there is nothing
+	 * to unshare.  Note that unsharing the address space or the
+	 * signal handlers also need to unshare the signal queues (aka
+	 * CLONE_THREAD).
+	 */
+	if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) {
+		if (!thread_group_empty(current))
+			return -EINVAL;
+	}
+	if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) {
+		if (refcount_read(&current->sighand->count) > 1)
+			return -EINVAL;
+	}
+	if (unshare_flags & CLONE_VM) {
+		if (!current_is_single_threaded())
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * Unshare the filesystem structure if it is being shared
+ */
+static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
+{
+	struct fs_struct *fs = current->fs;
+
+	if (!(unshare_flags & CLONE_FS) || !fs)
+		return 0;
+
+	/* don't need lock here; in the worst case we'll do useless copy */
+	if (fs->users == 1)
+		return 0;
+
+	*new_fsp = copy_fs_struct(fs);
+	if (!*new_fsp)
+		return -ENOMEM;
+
+	return 0;
+}
+
+/*
+ * Unshare file descriptor table if it is being shared
+ */
+int unshare_fd(unsigned long unshare_flags, unsigned int max_fds,
+	       struct files_struct **new_fdp)
+{
+	struct files_struct *fd = current->files;
+	int error = 0;
+
+	if ((unshare_flags & CLONE_FILES) &&
+	    (fd && atomic_read(&fd->count) > 1)) {
+		*new_fdp = dup_fd(fd, max_fds, &error);
+		if (!*new_fdp)
+			return error;
+	}
+
+	return 0;
+}
+
+/*
+ * unshare allows a process to 'unshare' part of the process
+ * context which was originally shared using clone.  copy_*
+ * functions used by kernel_clone() cannot be used here directly
+ * because they modify an inactive task_struct that is being
+ * constructed. Here we are modifying the current, active,
+ * task_struct.
+ */
+int ksys_unshare(unsigned long unshare_flags)
+{
+	struct fs_struct *fs, *new_fs = NULL;
+	struct files_struct *new_fd = NULL;
+	struct cred *new_cred = NULL;
+	struct nsproxy *new_nsproxy = NULL;
+	int do_sysvsem = 0;
+	int err;
+
+	/*
+	 * If unsharing a user namespace must also unshare the thread group
+	 * and unshare the filesystem root and working directories.
+	 */
+	if (unshare_flags & CLONE_NEWUSER)
+		unshare_flags |= CLONE_THREAD | CLONE_FS;
+	/*
+	 * If unsharing vm, must also unshare signal handlers.
+	 */
+	if (unshare_flags & CLONE_VM)
+		unshare_flags |= CLONE_SIGHAND;
+	/*
+	 * If unsharing a signal handlers, must also unshare the signal queues.
+	 */
+	if (unshare_flags & CLONE_SIGHAND)
+		unshare_flags |= CLONE_THREAD;
+	/*
+	 * If unsharing namespace, must also unshare filesystem information.
+	 */
+	if (unshare_flags & CLONE_NEWNS)
+		unshare_flags |= CLONE_FS;
+
+	err = check_unshare_flags(unshare_flags);
+	if (err)
+		goto bad_unshare_out;
+	/*
+	 * CLONE_NEWIPC must also detach from the undolist: after switching
+	 * to a new ipc namespace, the semaphore arrays from the old
+	 * namespace are unreachable.
+	 */
+	if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM))
+		do_sysvsem = 1;
+	err = unshare_fs(unshare_flags, &new_fs);
+	if (err)
+		goto bad_unshare_out;
+	err = unshare_fd(unshare_flags, NR_OPEN_MAX, &new_fd);
+	if (err)
+		goto bad_unshare_cleanup_fs;
+	err = unshare_userns(unshare_flags, &new_cred);
+	if (err)
+		goto bad_unshare_cleanup_fd;
+	err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy,
+					 new_cred, new_fs);
+	if (err)
+		goto bad_unshare_cleanup_cred;
+
+	if (new_cred) {
+		err = set_cred_ucounts(new_cred);
+		if (err)
+			goto bad_unshare_cleanup_cred;
+	}
+
+	if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) {
+		if (do_sysvsem) {
+			/*
+			 * CLONE_SYSVSEM is equivalent to sys_exit().
+			 */
+			exit_sem(current);
+		}
+		if (unshare_flags & CLONE_NEWIPC) {
+			/* Orphan segments in old ns (see sem above). */
+			exit_shm(current);
+			shm_init_task(current);
+		}
+
+		if (new_nsproxy)
+			switch_task_namespaces(current, new_nsproxy);
+
+		task_lock(current);
+
+		if (new_fs) {
+			fs = current->fs;
+			spin_lock(&fs->lock);
+			current->fs = new_fs;
+			if (--fs->users)
+				new_fs = NULL;
+			else
+				new_fs = fs;
+			spin_unlock(&fs->lock);
+		}
+
+		if (new_fd)
+			swap(current->files, new_fd);
+
+		task_unlock(current);
+
+		if (new_cred) {
+			/* Install the new user namespace */
+			commit_creds(new_cred);
+			new_cred = NULL;
+		}
+	}
+
+	perf_event_namespaces(current);
+
+bad_unshare_cleanup_cred:
+	if (new_cred)
+		put_cred(new_cred);
+bad_unshare_cleanup_fd:
+	if (new_fd)
+		put_files_struct(new_fd);
+
+bad_unshare_cleanup_fs:
+	if (new_fs)
+		free_fs_struct(new_fs);
+
+bad_unshare_out:
+	return err;
+}
+
+SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
+{
+	return ksys_unshare(unshare_flags);
+}
+
+/*
+ *	Helper to unshare the files of the current task.
+ *	We don't want to expose copy_files internals to
+ *	the exec layer of the kernel.
+ */
+
+int unshare_files(void)
+{
+	struct task_struct *task = current;
+	struct files_struct *old, *copy = NULL;
+	int error;
+
+	error = unshare_fd(CLONE_FILES, NR_OPEN_MAX, &copy);
+	if (error || !copy)
+		return error;
+
+	old = task->files;
+	task_lock(task);
+	task->files = copy;
+	task_unlock(task);
+	put_files_struct(old);
+	return 0;
+}
+
+int sysctl_max_threads(struct ctl_table *table, int write,
+		       void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table t;
+	int ret;
+	int threads = max_threads;
+	int min = 1;
+	int max = MAX_THREADS;
+
+	t = *table;
+	t.data = &threads;
+	t.extra1 = &min;
+	t.extra2 = &max;
+
+	ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
+	if (ret || !write)
+		return ret;
+
+	max_threads = threads;
+
+	return 0;
+}
diff --git a/kernel/freezer.c b/kernel/freezer.c
new file mode 100644
index 000000000..4fad0e6fc
--- /dev/null
+++ b/kernel/freezer.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/freezer.c - Function to freeze a process
+ *
+ * Originally from kernel/power/process.c
+ */
+
+#include <linux/interrupt.h>
+#include <linux/suspend.h>
+#include <linux/export.h>
+#include <linux/syscalls.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
+
+/* total number of freezing conditions in effect */
+DEFINE_STATIC_KEY_FALSE(freezer_active);
+EXPORT_SYMBOL(freezer_active);
+
+/*
+ * indicate whether PM freezing is in effect, protected by
+ * system_transition_mutex
+ */
+bool pm_freezing;
+bool pm_nosig_freezing;
+
+/* protects freezing and frozen transitions */
+static DEFINE_SPINLOCK(freezer_lock);
+
+/**
+ * freezing_slow_path - slow path for testing whether a task needs to be frozen
+ * @p: task to be tested
+ *
+ * This function is called by freezing() if freezer_active isn't zero
+ * and tests whether @p needs to enter and stay in frozen state.  Can be
+ * called under any context.  The freezers are responsible for ensuring the
+ * target tasks see the updated state.
+ */
+bool freezing_slow_path(struct task_struct *p)
+{
+	if (p->flags & (PF_NOFREEZE | PF_SUSPEND_TASK))
+		return false;
+
+	if (test_tsk_thread_flag(p, TIF_MEMDIE))
+		return false;
+
+	if (pm_nosig_freezing || cgroup_freezing(p))
+		return true;
+
+	if (pm_freezing && !(p->flags & PF_KTHREAD))
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL(freezing_slow_path);
+
+bool frozen(struct task_struct *p)
+{
+	return READ_ONCE(p->__state) & TASK_FROZEN;
+}
+
+/* Refrigerator is place where frozen processes are stored :-). */
+bool __refrigerator(bool check_kthr_stop)
+{
+	unsigned int state = get_current_state();
+	bool was_frozen = false;
+
+	pr_debug("%s entered refrigerator\n", current->comm);
+
+	WARN_ON_ONCE(state && !(state & TASK_NORMAL));
+
+	for (;;) {
+		bool freeze;
+
+		set_current_state(TASK_FROZEN);
+
+		spin_lock_irq(&freezer_lock);
+		freeze = freezing(current) && !(check_kthr_stop && kthread_should_stop());
+		spin_unlock_irq(&freezer_lock);
+
+		if (!freeze)
+			break;
+
+		was_frozen = true;
+		schedule();
+	}
+	__set_current_state(TASK_RUNNING);
+
+	pr_debug("%s left refrigerator\n", current->comm);
+
+	return was_frozen;
+}
+EXPORT_SYMBOL(__refrigerator);
+
+static void fake_signal_wake_up(struct task_struct *p)
+{
+	unsigned long flags;
+
+	if (lock_task_sighand(p, &flags)) {
+		signal_wake_up(p, 0);
+		unlock_task_sighand(p, &flags);
+	}
+}
+
+static int __set_task_frozen(struct task_struct *p, void *arg)
+{
+	unsigned int state = READ_ONCE(p->__state);
+
+	if (p->on_rq)
+		return 0;
+
+	if (p != current && task_curr(p))
+		return 0;
+
+	if (!(state & (TASK_FREEZABLE | __TASK_STOPPED | __TASK_TRACED)))
+		return 0;
+
+	/*
+	 * Only TASK_NORMAL can be augmented with TASK_FREEZABLE, since they
+	 * can suffer spurious wakeups.
+	 */
+	if (state & TASK_FREEZABLE)
+		WARN_ON_ONCE(!(state & TASK_NORMAL));
+
+#ifdef CONFIG_LOCKDEP
+	/*
+	 * It's dangerous to freeze with locks held; there be dragons there.
+	 */
+	if (!(state & __TASK_FREEZABLE_UNSAFE))
+		WARN_ON_ONCE(debug_locks && p->lockdep_depth);
+#endif
+
+	WRITE_ONCE(p->__state, TASK_FROZEN);
+	return TASK_FROZEN;
+}
+
+static bool __freeze_task(struct task_struct *p)
+{
+	/* TASK_FREEZABLE|TASK_STOPPED|TASK_TRACED -> TASK_FROZEN */
+	return task_call_func(p, __set_task_frozen, NULL);
+}
+
+/**
+ * freeze_task - send a freeze request to given task
+ * @p: task to send the request to
+ *
+ * If @p is freezing, the freeze request is sent either by sending a fake
+ * signal (if it's not a kernel thread) or waking it up (if it's a kernel
+ * thread).
+ *
+ * RETURNS:
+ * %false, if @p is not freezing or already frozen; %true, otherwise
+ */
+bool freeze_task(struct task_struct *p)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&freezer_lock, flags);
+	if (!freezing(p) || frozen(p) || __freeze_task(p)) {
+		spin_unlock_irqrestore(&freezer_lock, flags);
+		return false;
+	}
+
+	if (!(p->flags & PF_KTHREAD))
+		fake_signal_wake_up(p);
+	else
+		wake_up_state(p, TASK_NORMAL);
+
+	spin_unlock_irqrestore(&freezer_lock, flags);
+	return true;
+}
+
+/*
+ * The special task states (TASK_STOPPED, TASK_TRACED) keep their canonical
+ * state in p->jobctl. If either of them got a wakeup that was missed because
+ * TASK_FROZEN, then their canonical state reflects that and the below will
+ * refuse to restore the special state and instead issue the wakeup.
+ */
+static int __set_task_special(struct task_struct *p, void *arg)
+{
+	unsigned int state = 0;
+
+	if (p->jobctl & JOBCTL_TRACED)
+		state = TASK_TRACED;
+
+	else if (p->jobctl & JOBCTL_STOPPED)
+		state = TASK_STOPPED;
+
+	if (state)
+		WRITE_ONCE(p->__state, state);
+
+	return state;
+}
+
+void __thaw_task(struct task_struct *p)
+{
+	unsigned long flags, flags2;
+
+	spin_lock_irqsave(&freezer_lock, flags);
+	if (WARN_ON_ONCE(freezing(p)))
+		goto unlock;
+
+	if (lock_task_sighand(p, &flags2)) {
+		/* TASK_FROZEN -> TASK_{STOPPED,TRACED} */
+		bool ret = task_call_func(p, __set_task_special, NULL);
+		unlock_task_sighand(p, &flags2);
+		if (ret)
+			goto unlock;
+	}
+
+	wake_up_state(p, TASK_FROZEN);
+unlock:
+	spin_unlock_irqrestore(&freezer_lock, flags);
+}
+
+/**
+ * set_freezable - make %current freezable
+ *
+ * Mark %current freezable and enter refrigerator if necessary.
+ */
+bool set_freezable(void)
+{
+	might_sleep();
+
+	/*
+	 * Modify flags while holding freezer_lock.  This ensures the
+	 * freezer notices that we aren't frozen yet or the freezing
+	 * condition is visible to try_to_freeze() below.
+	 */
+	spin_lock_irq(&freezer_lock);
+	current->flags &= ~PF_NOFREEZE;
+	spin_unlock_irq(&freezer_lock);
+
+	return try_to_freeze();
+}
+EXPORT_SYMBOL(set_freezable);
diff --git a/kernel/futex/Makefile b/kernel/futex/Makefile
new file mode 100644
index 000000000..b77188d1f
--- /dev/null
+++ b/kernel/futex/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-y += core.o syscalls.o pi.o requeue.o waitwake.o
diff --git a/kernel/futex/core.c b/kernel/futex/core.c
new file mode 100644
index 000000000..d4141b054
--- /dev/null
+++ b/kernel/futex/core.c
@@ -0,0 +1,1159 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Fast Userspace Mutexes (which I call "Futexes!").
+ *  (C) Rusty Russell, IBM 2002
+ *
+ *  Generalized futexes, futex requeueing, misc fixes by Ingo Molnar
+ *  (C) Copyright 2003 Red Hat Inc, All Rights Reserved
+ *
+ *  Removed page pinning, fix privately mapped COW pages and other cleanups
+ *  (C) Copyright 2003, 2004 Jamie Lokier
+ *
+ *  Robust futex support started by Ingo Molnar
+ *  (C) Copyright 2006 Red Hat Inc, All Rights Reserved
+ *  Thanks to Thomas Gleixner for suggestions, analysis and fixes.
+ *
+ *  PI-futex support started by Ingo Molnar and Thomas Gleixner
+ *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *  Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *
+ *  PRIVATE futexes by Eric Dumazet
+ *  Copyright (C) 2007 Eric Dumazet <dada1@cosmosbay.com>
+ *
+ *  Requeue-PI support by Darren Hart <dvhltc@us.ibm.com>
+ *  Copyright (C) IBM Corporation, 2009
+ *  Thanks to Thomas Gleixner for conceptual design and careful reviews.
+ *
+ *  Thanks to Ben LaHaise for yelling "hashed waitqueues" loudly
+ *  enough at me, Linus for the original (flawed) idea, Matthew
+ *  Kirkwood for proof-of-concept implementation.
+ *
+ *  "The futexes are also cursed."
+ *  "But they come in a choice of three flavours!"
+ */
+#include <linux/compat.h>
+#include <linux/jhash.h>
+#include <linux/pagemap.h>
+#include <linux/memblock.h>
+#include <linux/fault-inject.h>
+#include <linux/slab.h>
+
+#include "futex.h"
+#include "../locking/rtmutex_common.h"
+
+/*
+ * The base of the bucket array and its size are always used together
+ * (after initialization only in futex_hash()), so ensure that they
+ * reside in the same cacheline.
+ */
+static struct {
+	struct futex_hash_bucket *queues;
+	unsigned long            hashsize;
+} __futex_data __read_mostly __aligned(2*sizeof(long));
+#define futex_queues   (__futex_data.queues)
+#define futex_hashsize (__futex_data.hashsize)
+
+
+/*
+ * Fault injections for futexes.
+ */
+#ifdef CONFIG_FAIL_FUTEX
+
+static struct {
+	struct fault_attr attr;
+
+	bool ignore_private;
+} fail_futex = {
+	.attr = FAULT_ATTR_INITIALIZER,
+	.ignore_private = false,
+};
+
+static int __init setup_fail_futex(char *str)
+{
+	return setup_fault_attr(&fail_futex.attr, str);
+}
+__setup("fail_futex=", setup_fail_futex);
+
+bool should_fail_futex(bool fshared)
+{
+	if (fail_futex.ignore_private && !fshared)
+		return false;
+
+	return should_fail(&fail_futex.attr, 1);
+}
+
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+
+static int __init fail_futex_debugfs(void)
+{
+	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
+	struct dentry *dir;
+
+	dir = fault_create_debugfs_attr("fail_futex", NULL,
+					&fail_futex.attr);
+	if (IS_ERR(dir))
+		return PTR_ERR(dir);
+
+	debugfs_create_bool("ignore-private", mode, dir,
+			    &fail_futex.ignore_private);
+	return 0;
+}
+
+late_initcall(fail_futex_debugfs);
+
+#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
+
+#endif /* CONFIG_FAIL_FUTEX */
+
+/**
+ * futex_hash - Return the hash bucket in the global hash
+ * @key:	Pointer to the futex key for which the hash is calculated
+ *
+ * We hash on the keys returned from get_futex_key (see below) and return the
+ * corresponding hash bucket in the global hash.
+ */
+struct futex_hash_bucket *futex_hash(union futex_key *key)
+{
+	u32 hash = jhash2((u32 *)key, offsetof(typeof(*key), both.offset) / 4,
+			  key->both.offset);
+
+	return &futex_queues[hash & (futex_hashsize - 1)];
+}
+
+
+/**
+ * futex_setup_timer - set up the sleeping hrtimer.
+ * @time:	ptr to the given timeout value
+ * @timeout:	the hrtimer_sleeper structure to be set up
+ * @flags:	futex flags
+ * @range_ns:	optional range in ns
+ *
+ * Return: Initialized hrtimer_sleeper structure or NULL if no timeout
+ *	   value given
+ */
+struct hrtimer_sleeper *
+futex_setup_timer(ktime_t *time, struct hrtimer_sleeper *timeout,
+		  int flags, u64 range_ns)
+{
+	if (!time)
+		return NULL;
+
+	hrtimer_init_sleeper_on_stack(timeout, (flags & FLAGS_CLOCKRT) ?
+				      CLOCK_REALTIME : CLOCK_MONOTONIC,
+				      HRTIMER_MODE_ABS);
+	/*
+	 * If range_ns is 0, calling hrtimer_set_expires_range_ns() is
+	 * effectively the same as calling hrtimer_set_expires().
+	 */
+	hrtimer_set_expires_range_ns(&timeout->timer, *time, range_ns);
+
+	return timeout;
+}
+
+/*
+ * Generate a machine wide unique identifier for this inode.
+ *
+ * This relies on u64 not wrapping in the life-time of the machine; which with
+ * 1ns resolution means almost 585 years.
+ *
+ * This further relies on the fact that a well formed program will not unmap
+ * the file while it has a (shared) futex waiting on it. This mapping will have
+ * a file reference which pins the mount and inode.
+ *
+ * If for some reason an inode gets evicted and read back in again, it will get
+ * a new sequence number and will _NOT_ match, even though it is the exact same
+ * file.
+ *
+ * It is important that futex_match() will never have a false-positive, esp.
+ * for PI futexes that can mess up the state. The above argues that false-negatives
+ * are only possible for malformed programs.
+ */
+static u64 get_inode_sequence_number(struct inode *inode)
+{
+	static atomic64_t i_seq;
+	u64 old;
+
+	/* Does the inode already have a sequence number? */
+	old = atomic64_read(&inode->i_sequence);
+	if (likely(old))
+		return old;
+
+	for (;;) {
+		u64 new = atomic64_add_return(1, &i_seq);
+		if (WARN_ON_ONCE(!new))
+			continue;
+
+		old = atomic64_cmpxchg_relaxed(&inode->i_sequence, 0, new);
+		if (old)
+			return old;
+		return new;
+	}
+}
+
+/**
+ * get_futex_key() - Get parameters which are the keys for a futex
+ * @uaddr:	virtual address of the futex
+ * @fshared:	false for a PROCESS_PRIVATE futex, true for PROCESS_SHARED
+ * @key:	address where result is stored.
+ * @rw:		mapping needs to be read/write (values: FUTEX_READ,
+ *              FUTEX_WRITE)
+ *
+ * Return: a negative error code or 0
+ *
+ * The key words are stored in @key on success.
+ *
+ * For shared mappings (when @fshared), the key is:
+ *
+ *   ( inode->i_sequence, page->index, offset_within_page )
+ *
+ * [ also see get_inode_sequence_number() ]
+ *
+ * For private mappings (or when !@fshared), the key is:
+ *
+ *   ( current->mm, address, 0 )
+ *
+ * This allows (cross process, where applicable) identification of the futex
+ * without keeping the page pinned for the duration of the FUTEX_WAIT.
+ *
+ * lock_page() might sleep, the caller should not hold a spinlock.
+ */
+int get_futex_key(u32 __user *uaddr, bool fshared, union futex_key *key,
+		  enum futex_access rw)
+{
+	unsigned long address = (unsigned long)uaddr;
+	struct mm_struct *mm = current->mm;
+	struct page *page, *tail;
+	struct address_space *mapping;
+	int err, ro = 0;
+
+	/*
+	 * The futex address must be "naturally" aligned.
+	 */
+	key->both.offset = address % PAGE_SIZE;
+	if (unlikely((address % sizeof(u32)) != 0))
+		return -EINVAL;
+	address -= key->both.offset;
+
+	if (unlikely(!access_ok(uaddr, sizeof(u32))))
+		return -EFAULT;
+
+	if (unlikely(should_fail_futex(fshared)))
+		return -EFAULT;
+
+	/*
+	 * PROCESS_PRIVATE futexes are fast.
+	 * As the mm cannot disappear under us and the 'key' only needs
+	 * virtual address, we dont even have to find the underlying vma.
+	 * Note : We do have to check 'uaddr' is a valid user address,
+	 *        but access_ok() should be faster than find_vma()
+	 */
+	if (!fshared) {
+		/*
+		 * On no-MMU, shared futexes are treated as private, therefore
+		 * we must not include the current process in the key. Since
+		 * there is only one address space, the address is a unique key
+		 * on its own.
+		 */
+		if (IS_ENABLED(CONFIG_MMU))
+			key->private.mm = mm;
+		else
+			key->private.mm = NULL;
+
+		key->private.address = address;
+		return 0;
+	}
+
+again:
+	/* Ignore any VERIFY_READ mapping (futex common case) */
+	if (unlikely(should_fail_futex(true)))
+		return -EFAULT;
+
+	err = get_user_pages_fast(address, 1, FOLL_WRITE, &page);
+	/*
+	 * If write access is not required (eg. FUTEX_WAIT), try
+	 * and get read-only access.
+	 */
+	if (err == -EFAULT && rw == FUTEX_READ) {
+		err = get_user_pages_fast(address, 1, 0, &page);
+		ro = 1;
+	}
+	if (err < 0)
+		return err;
+	else
+		err = 0;
+
+	/*
+	 * The treatment of mapping from this point on is critical. The page
+	 * lock protects many things but in this context the page lock
+	 * stabilizes mapping, prevents inode freeing in the shared
+	 * file-backed region case and guards against movement to swap cache.
+	 *
+	 * Strictly speaking the page lock is not needed in all cases being
+	 * considered here and page lock forces unnecessarily serialization
+	 * From this point on, mapping will be re-verified if necessary and
+	 * page lock will be acquired only if it is unavoidable
+	 *
+	 * Mapping checks require the head page for any compound page so the
+	 * head page and mapping is looked up now. For anonymous pages, it
+	 * does not matter if the page splits in the future as the key is
+	 * based on the address. For filesystem-backed pages, the tail is
+	 * required as the index of the page determines the key. For
+	 * base pages, there is no tail page and tail == page.
+	 */
+	tail = page;
+	page = compound_head(page);
+	mapping = READ_ONCE(page->mapping);
+
+	/*
+	 * If page->mapping is NULL, then it cannot be a PageAnon
+	 * page; but it might be the ZERO_PAGE or in the gate area or
+	 * in a special mapping (all cases which we are happy to fail);
+	 * or it may have been a good file page when get_user_pages_fast
+	 * found it, but truncated or holepunched or subjected to
+	 * invalidate_complete_page2 before we got the page lock (also
+	 * cases which we are happy to fail).  And we hold a reference,
+	 * so refcount care in invalidate_inode_page's remove_mapping
+	 * prevents drop_caches from setting mapping to NULL beneath us.
+	 *
+	 * The case we do have to guard against is when memory pressure made
+	 * shmem_writepage move it from filecache to swapcache beneath us:
+	 * an unlikely race, but we do need to retry for page->mapping.
+	 */
+	if (unlikely(!mapping)) {
+		int shmem_swizzled;
+
+		/*
+		 * Page lock is required to identify which special case above
+		 * applies. If this is really a shmem page then the page lock
+		 * will prevent unexpected transitions.
+		 */
+		lock_page(page);
+		shmem_swizzled = PageSwapCache(page) || page->mapping;
+		unlock_page(page);
+		put_page(page);
+
+		if (shmem_swizzled)
+			goto again;
+
+		return -EFAULT;
+	}
+
+	/*
+	 * Private mappings are handled in a simple way.
+	 *
+	 * If the futex key is stored on an anonymous page, then the associated
+	 * object is the mm which is implicitly pinned by the calling process.
+	 *
+	 * NOTE: When userspace waits on a MAP_SHARED mapping, even if
+	 * it's a read-only handle, it's expected that futexes attach to
+	 * the object not the particular process.
+	 */
+	if (PageAnon(page)) {
+		/*
+		 * A RO anonymous page will never change and thus doesn't make
+		 * sense for futex operations.
+		 */
+		if (unlikely(should_fail_futex(true)) || ro) {
+			err = -EFAULT;
+			goto out;
+		}
+
+		key->both.offset |= FUT_OFF_MMSHARED; /* ref taken on mm */
+		key->private.mm = mm;
+		key->private.address = address;
+
+	} else {
+		struct inode *inode;
+
+		/*
+		 * The associated futex object in this case is the inode and
+		 * the page->mapping must be traversed. Ordinarily this should
+		 * be stabilised under page lock but it's not strictly
+		 * necessary in this case as we just want to pin the inode, not
+		 * update the radix tree or anything like that.
+		 *
+		 * The RCU read lock is taken as the inode is finally freed
+		 * under RCU. If the mapping still matches expectations then the
+		 * mapping->host can be safely accessed as being a valid inode.
+		 */
+		rcu_read_lock();
+
+		if (READ_ONCE(page->mapping) != mapping) {
+			rcu_read_unlock();
+			put_page(page);
+
+			goto again;
+		}
+
+		inode = READ_ONCE(mapping->host);
+		if (!inode) {
+			rcu_read_unlock();
+			put_page(page);
+
+			goto again;
+		}
+
+		key->both.offset |= FUT_OFF_INODE; /* inode-based key */
+		key->shared.i_seq = get_inode_sequence_number(inode);
+		key->shared.pgoff = page_to_pgoff(tail);
+		rcu_read_unlock();
+	}
+
+out:
+	put_page(page);
+	return err;
+}
+
+/**
+ * fault_in_user_writeable() - Fault in user address and verify RW access
+ * @uaddr:	pointer to faulting user space address
+ *
+ * Slow path to fixup the fault we just took in the atomic write
+ * access to @uaddr.
+ *
+ * We have no generic implementation of a non-destructive write to the
+ * user address. We know that we faulted in the atomic pagefault
+ * disabled section so we can as well avoid the #PF overhead by
+ * calling get_user_pages() right away.
+ */
+int fault_in_user_writeable(u32 __user *uaddr)
+{
+	struct mm_struct *mm = current->mm;
+	int ret;
+
+	mmap_read_lock(mm);
+	ret = fixup_user_fault(mm, (unsigned long)uaddr,
+			       FAULT_FLAG_WRITE, NULL);
+	mmap_read_unlock(mm);
+
+	return ret < 0 ? ret : 0;
+}
+
+/**
+ * futex_top_waiter() - Return the highest priority waiter on a futex
+ * @hb:		the hash bucket the futex_q's reside in
+ * @key:	the futex key (to distinguish it from other futex futex_q's)
+ *
+ * Must be called with the hb lock held.
+ */
+struct futex_q *futex_top_waiter(struct futex_hash_bucket *hb, union futex_key *key)
+{
+	struct futex_q *this;
+
+	plist_for_each_entry(this, &hb->chain, list) {
+		if (futex_match(&this->key, key))
+			return this;
+	}
+	return NULL;
+}
+
+int futex_cmpxchg_value_locked(u32 *curval, u32 __user *uaddr, u32 uval, u32 newval)
+{
+	int ret;
+
+	pagefault_disable();
+	ret = futex_atomic_cmpxchg_inatomic(curval, uaddr, uval, newval);
+	pagefault_enable();
+
+	return ret;
+}
+
+int futex_get_value_locked(u32 *dest, u32 __user *from)
+{
+	int ret;
+
+	pagefault_disable();
+	ret = __get_user(*dest, from);
+	pagefault_enable();
+
+	return ret ? -EFAULT : 0;
+}
+
+/**
+ * wait_for_owner_exiting - Block until the owner has exited
+ * @ret: owner's current futex lock status
+ * @exiting:	Pointer to the exiting task
+ *
+ * Caller must hold a refcount on @exiting.
+ */
+void wait_for_owner_exiting(int ret, struct task_struct *exiting)
+{
+	if (ret != -EBUSY) {
+		WARN_ON_ONCE(exiting);
+		return;
+	}
+
+	if (WARN_ON_ONCE(ret == -EBUSY && !exiting))
+		return;
+
+	mutex_lock(&exiting->futex_exit_mutex);
+	/*
+	 * No point in doing state checking here. If the waiter got here
+	 * while the task was in exec()->exec_futex_release() then it can
+	 * have any FUTEX_STATE_* value when the waiter has acquired the
+	 * mutex. OK, if running, EXITING or DEAD if it reached exit()
+	 * already. Highly unlikely and not a problem. Just one more round
+	 * through the futex maze.
+	 */
+	mutex_unlock(&exiting->futex_exit_mutex);
+
+	put_task_struct(exiting);
+}
+
+/**
+ * __futex_unqueue() - Remove the futex_q from its futex_hash_bucket
+ * @q:	The futex_q to unqueue
+ *
+ * The q->lock_ptr must not be NULL and must be held by the caller.
+ */
+void __futex_unqueue(struct futex_q *q)
+{
+	struct futex_hash_bucket *hb;
+
+	if (WARN_ON_SMP(!q->lock_ptr) || WARN_ON(plist_node_empty(&q->list)))
+		return;
+	lockdep_assert_held(q->lock_ptr);
+
+	hb = container_of(q->lock_ptr, struct futex_hash_bucket, lock);
+	plist_del(&q->list, &hb->chain);
+	futex_hb_waiters_dec(hb);
+}
+
+/* The key must be already stored in q->key. */
+struct futex_hash_bucket *futex_q_lock(struct futex_q *q)
+	__acquires(&hb->lock)
+{
+	struct futex_hash_bucket *hb;
+
+	hb = futex_hash(&q->key);
+
+	/*
+	 * Increment the counter before taking the lock so that
+	 * a potential waker won't miss a to-be-slept task that is
+	 * waiting for the spinlock. This is safe as all futex_q_lock()
+	 * users end up calling futex_queue(). Similarly, for housekeeping,
+	 * decrement the counter at futex_q_unlock() when some error has
+	 * occurred and we don't end up adding the task to the list.
+	 */
+	futex_hb_waiters_inc(hb); /* implies smp_mb(); (A) */
+
+	q->lock_ptr = &hb->lock;
+
+	spin_lock(&hb->lock);
+	return hb;
+}
+
+void futex_q_unlock(struct futex_hash_bucket *hb)
+	__releases(&hb->lock)
+{
+	spin_unlock(&hb->lock);
+	futex_hb_waiters_dec(hb);
+}
+
+void __futex_queue(struct futex_q *q, struct futex_hash_bucket *hb)
+{
+	int prio;
+
+	/*
+	 * The priority used to register this element is
+	 * - either the real thread-priority for the real-time threads
+	 * (i.e. threads with a priority lower than MAX_RT_PRIO)
+	 * - or MAX_RT_PRIO for non-RT threads.
+	 * Thus, all RT-threads are woken first in priority order, and
+	 * the others are woken last, in FIFO order.
+	 */
+	prio = min(current->normal_prio, MAX_RT_PRIO);
+
+	plist_node_init(&q->list, prio);
+	plist_add(&q->list, &hb->chain);
+	q->task = current;
+}
+
+/**
+ * futex_unqueue() - Remove the futex_q from its futex_hash_bucket
+ * @q:	The futex_q to unqueue
+ *
+ * The q->lock_ptr must not be held by the caller. A call to futex_unqueue() must
+ * be paired with exactly one earlier call to futex_queue().
+ *
+ * Return:
+ *  - 1 - if the futex_q was still queued (and we removed unqueued it);
+ *  - 0 - if the futex_q was already removed by the waking thread
+ */
+int futex_unqueue(struct futex_q *q)
+{
+	spinlock_t *lock_ptr;
+	int ret = 0;
+
+	/* In the common case we don't take the spinlock, which is nice. */
+retry:
+	/*
+	 * q->lock_ptr can change between this read and the following spin_lock.
+	 * Use READ_ONCE to forbid the compiler from reloading q->lock_ptr and
+	 * optimizing lock_ptr out of the logic below.
+	 */
+	lock_ptr = READ_ONCE(q->lock_ptr);
+	if (lock_ptr != NULL) {
+		spin_lock(lock_ptr);
+		/*
+		 * q->lock_ptr can change between reading it and
+		 * spin_lock(), causing us to take the wrong lock.  This
+		 * corrects the race condition.
+		 *
+		 * Reasoning goes like this: if we have the wrong lock,
+		 * q->lock_ptr must have changed (maybe several times)
+		 * between reading it and the spin_lock().  It can
+		 * change again after the spin_lock() but only if it was
+		 * already changed before the spin_lock().  It cannot,
+		 * however, change back to the original value.  Therefore
+		 * we can detect whether we acquired the correct lock.
+		 */
+		if (unlikely(lock_ptr != q->lock_ptr)) {
+			spin_unlock(lock_ptr);
+			goto retry;
+		}
+		__futex_unqueue(q);
+
+		BUG_ON(q->pi_state);
+
+		spin_unlock(lock_ptr);
+		ret = 1;
+	}
+
+	return ret;
+}
+
+/*
+ * PI futexes can not be requeued and must remove themselves from the
+ * hash bucket. The hash bucket lock (i.e. lock_ptr) is held.
+ */
+void futex_unqueue_pi(struct futex_q *q)
+{
+	__futex_unqueue(q);
+
+	BUG_ON(!q->pi_state);
+	put_pi_state(q->pi_state);
+	q->pi_state = NULL;
+}
+
+/* Constants for the pending_op argument of handle_futex_death */
+#define HANDLE_DEATH_PENDING	true
+#define HANDLE_DEATH_LIST	false
+
+/*
+ * Process a futex-list entry, check whether it's owned by the
+ * dying task, and do notification if so:
+ */
+static int handle_futex_death(u32 __user *uaddr, struct task_struct *curr,
+			      bool pi, bool pending_op)
+{
+	u32 uval, nval, mval;
+	pid_t owner;
+	int err;
+
+	/* Futex address must be 32bit aligned */
+	if ((((unsigned long)uaddr) % sizeof(*uaddr)) != 0)
+		return -1;
+
+retry:
+	if (get_user(uval, uaddr))
+		return -1;
+
+	/*
+	 * Special case for regular (non PI) futexes. The unlock path in
+	 * user space has two race scenarios:
+	 *
+	 * 1. The unlock path releases the user space futex value and
+	 *    before it can execute the futex() syscall to wake up
+	 *    waiters it is killed.
+	 *
+	 * 2. A woken up waiter is killed before it can acquire the
+	 *    futex in user space.
+	 *
+	 * In the second case, the wake up notification could be generated
+	 * by the unlock path in user space after setting the futex value
+	 * to zero or by the kernel after setting the OWNER_DIED bit below.
+	 *
+	 * In both cases the TID validation below prevents a wakeup of
+	 * potential waiters which can cause these waiters to block
+	 * forever.
+	 *
+	 * In both cases the following conditions are met:
+	 *
+	 *	1) task->robust_list->list_op_pending != NULL
+	 *	   @pending_op == true
+	 *	2) The owner part of user space futex value == 0
+	 *	3) Regular futex: @pi == false
+	 *
+	 * If these conditions are met, it is safe to attempt waking up a
+	 * potential waiter without touching the user space futex value and
+	 * trying to set the OWNER_DIED bit. If the futex value is zero,
+	 * the rest of the user space mutex state is consistent, so a woken
+	 * waiter will just take over the uncontended futex. Setting the
+	 * OWNER_DIED bit would create inconsistent state and malfunction
+	 * of the user space owner died handling. Otherwise, the OWNER_DIED
+	 * bit is already set, and the woken waiter is expected to deal with
+	 * this.
+	 */
+	owner = uval & FUTEX_TID_MASK;
+
+	if (pending_op && !pi && !owner) {
+		futex_wake(uaddr, 1, 1, FUTEX_BITSET_MATCH_ANY);
+		return 0;
+	}
+
+	if (owner != task_pid_vnr(curr))
+		return 0;
+
+	/*
+	 * Ok, this dying thread is truly holding a futex
+	 * of interest. Set the OWNER_DIED bit atomically
+	 * via cmpxchg, and if the value had FUTEX_WAITERS
+	 * set, wake up a waiter (if any). (We have to do a
+	 * futex_wake() even if OWNER_DIED is already set -
+	 * to handle the rare but possible case of recursive
+	 * thread-death.) The rest of the cleanup is done in
+	 * userspace.
+	 */
+	mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
+
+	/*
+	 * We are not holding a lock here, but we want to have
+	 * the pagefault_disable/enable() protection because
+	 * we want to handle the fault gracefully. If the
+	 * access fails we try to fault in the futex with R/W
+	 * verification via get_user_pages. get_user() above
+	 * does not guarantee R/W access. If that fails we
+	 * give up and leave the futex locked.
+	 */
+	if ((err = futex_cmpxchg_value_locked(&nval, uaddr, uval, mval))) {
+		switch (err) {
+		case -EFAULT:
+			if (fault_in_user_writeable(uaddr))
+				return -1;
+			goto retry;
+
+		case -EAGAIN:
+			cond_resched();
+			goto retry;
+
+		default:
+			WARN_ON_ONCE(1);
+			return err;
+		}
+	}
+
+	if (nval != uval)
+		goto retry;
+
+	/*
+	 * Wake robust non-PI futexes here. The wakeup of
+	 * PI futexes happens in exit_pi_state():
+	 */
+	if (!pi && (uval & FUTEX_WAITERS))
+		futex_wake(uaddr, 1, 1, FUTEX_BITSET_MATCH_ANY);
+
+	return 0;
+}
+
+/*
+ * Fetch a robust-list pointer. Bit 0 signals PI futexes:
+ */
+static inline int fetch_robust_entry(struct robust_list __user **entry,
+				     struct robust_list __user * __user *head,
+				     unsigned int *pi)
+{
+	unsigned long uentry;
+
+	if (get_user(uentry, (unsigned long __user *)head))
+		return -EFAULT;
+
+	*entry = (void __user *)(uentry & ~1UL);
+	*pi = uentry & 1;
+
+	return 0;
+}
+
+/*
+ * Walk curr->robust_list (very carefully, it's a userspace list!)
+ * and mark any locks found there dead, and notify any waiters.
+ *
+ * We silently return on any sign of list-walking problem.
+ */
+static void exit_robust_list(struct task_struct *curr)
+{
+	struct robust_list_head __user *head = curr->robust_list;
+	struct robust_list __user *entry, *next_entry, *pending;
+	unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
+	unsigned int next_pi;
+	unsigned long futex_offset;
+	int rc;
+
+	/*
+	 * Fetch the list head (which was registered earlier, via
+	 * sys_set_robust_list()):
+	 */
+	if (fetch_robust_entry(&entry, &head->list.next, &pi))
+		return;
+	/*
+	 * Fetch the relative futex offset:
+	 */
+	if (get_user(futex_offset, &head->futex_offset))
+		return;
+	/*
+	 * Fetch any possibly pending lock-add first, and handle it
+	 * if it exists:
+	 */
+	if (fetch_robust_entry(&pending, &head->list_op_pending, &pip))
+		return;
+
+	next_entry = NULL;	/* avoid warning with gcc */
+	while (entry != &head->list) {
+		/*
+		 * Fetch the next entry in the list before calling
+		 * handle_futex_death:
+		 */
+		rc = fetch_robust_entry(&next_entry, &entry->next, &next_pi);
+		/*
+		 * A pending lock might already be on the list, so
+		 * don't process it twice:
+		 */
+		if (entry != pending) {
+			if (handle_futex_death((void __user *)entry + futex_offset,
+						curr, pi, HANDLE_DEATH_LIST))
+				return;
+		}
+		if (rc)
+			return;
+		entry = next_entry;
+		pi = next_pi;
+		/*
+		 * Avoid excessively long or circular lists:
+		 */
+		if (!--limit)
+			break;
+
+		cond_resched();
+	}
+
+	if (pending) {
+		handle_futex_death((void __user *)pending + futex_offset,
+				   curr, pip, HANDLE_DEATH_PENDING);
+	}
+}
+
+#ifdef CONFIG_COMPAT
+static void __user *futex_uaddr(struct robust_list __user *entry,
+				compat_long_t futex_offset)
+{
+	compat_uptr_t base = ptr_to_compat(entry);
+	void __user *uaddr = compat_ptr(base + futex_offset);
+
+	return uaddr;
+}
+
+/*
+ * Fetch a robust-list pointer. Bit 0 signals PI futexes:
+ */
+static inline int
+compat_fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry,
+		   compat_uptr_t __user *head, unsigned int *pi)
+{
+	if (get_user(*uentry, head))
+		return -EFAULT;
+
+	*entry = compat_ptr((*uentry) & ~1);
+	*pi = (unsigned int)(*uentry) & 1;
+
+	return 0;
+}
+
+/*
+ * Walk curr->robust_list (very carefully, it's a userspace list!)
+ * and mark any locks found there dead, and notify any waiters.
+ *
+ * We silently return on any sign of list-walking problem.
+ */
+static void compat_exit_robust_list(struct task_struct *curr)
+{
+	struct compat_robust_list_head __user *head = curr->compat_robust_list;
+	struct robust_list __user *entry, *next_entry, *pending;
+	unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
+	unsigned int next_pi;
+	compat_uptr_t uentry, next_uentry, upending;
+	compat_long_t futex_offset;
+	int rc;
+
+	/*
+	 * Fetch the list head (which was registered earlier, via
+	 * sys_set_robust_list()):
+	 */
+	if (compat_fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
+		return;
+	/*
+	 * Fetch the relative futex offset:
+	 */
+	if (get_user(futex_offset, &head->futex_offset))
+		return;
+	/*
+	 * Fetch any possibly pending lock-add first, and handle it
+	 * if it exists:
+	 */
+	if (compat_fetch_robust_entry(&upending, &pending,
+			       &head->list_op_pending, &pip))
+		return;
+
+	next_entry = NULL;	/* avoid warning with gcc */
+	while (entry != (struct robust_list __user *) &head->list) {
+		/*
+		 * Fetch the next entry in the list before calling
+		 * handle_futex_death:
+		 */
+		rc = compat_fetch_robust_entry(&next_uentry, &next_entry,
+			(compat_uptr_t __user *)&entry->next, &next_pi);
+		/*
+		 * A pending lock might already be on the list, so
+		 * dont process it twice:
+		 */
+		if (entry != pending) {
+			void __user *uaddr = futex_uaddr(entry, futex_offset);
+
+			if (handle_futex_death(uaddr, curr, pi,
+					       HANDLE_DEATH_LIST))
+				return;
+		}
+		if (rc)
+			return;
+		uentry = next_uentry;
+		entry = next_entry;
+		pi = next_pi;
+		/*
+		 * Avoid excessively long or circular lists:
+		 */
+		if (!--limit)
+			break;
+
+		cond_resched();
+	}
+	if (pending) {
+		void __user *uaddr = futex_uaddr(pending, futex_offset);
+
+		handle_futex_death(uaddr, curr, pip, HANDLE_DEATH_PENDING);
+	}
+}
+#endif
+
+#ifdef CONFIG_FUTEX_PI
+
+/*
+ * This task is holding PI mutexes at exit time => bad.
+ * Kernel cleans up PI-state, but userspace is likely hosed.
+ * (Robust-futex cleanup is separate and might save the day for userspace.)
+ */
+static void exit_pi_state_list(struct task_struct *curr)
+{
+	struct list_head *next, *head = &curr->pi_state_list;
+	struct futex_pi_state *pi_state;
+	struct futex_hash_bucket *hb;
+	union futex_key key = FUTEX_KEY_INIT;
+
+	/*
+	 * We are a ZOMBIE and nobody can enqueue itself on
+	 * pi_state_list anymore, but we have to be careful
+	 * versus waiters unqueueing themselves:
+	 */
+	raw_spin_lock_irq(&curr->pi_lock);
+	while (!list_empty(head)) {
+		next = head->next;
+		pi_state = list_entry(next, struct futex_pi_state, list);
+		key = pi_state->key;
+		hb = futex_hash(&key);
+
+		/*
+		 * We can race against put_pi_state() removing itself from the
+		 * list (a waiter going away). put_pi_state() will first
+		 * decrement the reference count and then modify the list, so
+		 * its possible to see the list entry but fail this reference
+		 * acquire.
+		 *
+		 * In that case; drop the locks to let put_pi_state() make
+		 * progress and retry the loop.
+		 */
+		if (!refcount_inc_not_zero(&pi_state->refcount)) {
+			raw_spin_unlock_irq(&curr->pi_lock);
+			cpu_relax();
+			raw_spin_lock_irq(&curr->pi_lock);
+			continue;
+		}
+		raw_spin_unlock_irq(&curr->pi_lock);
+
+		spin_lock(&hb->lock);
+		raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+		raw_spin_lock(&curr->pi_lock);
+		/*
+		 * We dropped the pi-lock, so re-check whether this
+		 * task still owns the PI-state:
+		 */
+		if (head->next != next) {
+			/* retain curr->pi_lock for the loop invariant */
+			raw_spin_unlock(&pi_state->pi_mutex.wait_lock);
+			spin_unlock(&hb->lock);
+			put_pi_state(pi_state);
+			continue;
+		}
+
+		WARN_ON(pi_state->owner != curr);
+		WARN_ON(list_empty(&pi_state->list));
+		list_del_init(&pi_state->list);
+		pi_state->owner = NULL;
+
+		raw_spin_unlock(&curr->pi_lock);
+		raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
+		spin_unlock(&hb->lock);
+
+		rt_mutex_futex_unlock(&pi_state->pi_mutex);
+		put_pi_state(pi_state);
+
+		raw_spin_lock_irq(&curr->pi_lock);
+	}
+	raw_spin_unlock_irq(&curr->pi_lock);
+}
+#else
+static inline void exit_pi_state_list(struct task_struct *curr) { }
+#endif
+
+static void futex_cleanup(struct task_struct *tsk)
+{
+	if (unlikely(tsk->robust_list)) {
+		exit_robust_list(tsk);
+		tsk->robust_list = NULL;
+	}
+
+#ifdef CONFIG_COMPAT
+	if (unlikely(tsk->compat_robust_list)) {
+		compat_exit_robust_list(tsk);
+		tsk->compat_robust_list = NULL;
+	}
+#endif
+
+	if (unlikely(!list_empty(&tsk->pi_state_list)))
+		exit_pi_state_list(tsk);
+}
+
+/**
+ * futex_exit_recursive - Set the tasks futex state to FUTEX_STATE_DEAD
+ * @tsk:	task to set the state on
+ *
+ * Set the futex exit state of the task lockless. The futex waiter code
+ * observes that state when a task is exiting and loops until the task has
+ * actually finished the futex cleanup. The worst case for this is that the
+ * waiter runs through the wait loop until the state becomes visible.
+ *
+ * This is called from the recursive fault handling path in make_task_dead().
+ *
+ * This is best effort. Either the futex exit code has run already or
+ * not. If the OWNER_DIED bit has been set on the futex then the waiter can
+ * take it over. If not, the problem is pushed back to user space. If the
+ * futex exit code did not run yet, then an already queued waiter might
+ * block forever, but there is nothing which can be done about that.
+ */
+void futex_exit_recursive(struct task_struct *tsk)
+{
+	/* If the state is FUTEX_STATE_EXITING then futex_exit_mutex is held */
+	if (tsk->futex_state == FUTEX_STATE_EXITING)
+		mutex_unlock(&tsk->futex_exit_mutex);
+	tsk->futex_state = FUTEX_STATE_DEAD;
+}
+
+static void futex_cleanup_begin(struct task_struct *tsk)
+{
+	/*
+	 * Prevent various race issues against a concurrent incoming waiter
+	 * including live locks by forcing the waiter to block on
+	 * tsk->futex_exit_mutex when it observes FUTEX_STATE_EXITING in
+	 * attach_to_pi_owner().
+	 */
+	mutex_lock(&tsk->futex_exit_mutex);
+
+	/*
+	 * Switch the state to FUTEX_STATE_EXITING under tsk->pi_lock.
+	 *
+	 * This ensures that all subsequent checks of tsk->futex_state in
+	 * attach_to_pi_owner() must observe FUTEX_STATE_EXITING with
+	 * tsk->pi_lock held.
+	 *
+	 * It guarantees also that a pi_state which was queued right before
+	 * the state change under tsk->pi_lock by a concurrent waiter must
+	 * be observed in exit_pi_state_list().
+	 */
+	raw_spin_lock_irq(&tsk->pi_lock);
+	tsk->futex_state = FUTEX_STATE_EXITING;
+	raw_spin_unlock_irq(&tsk->pi_lock);
+}
+
+static void futex_cleanup_end(struct task_struct *tsk, int state)
+{
+	/*
+	 * Lockless store. The only side effect is that an observer might
+	 * take another loop until it becomes visible.
+	 */
+	tsk->futex_state = state;
+	/*
+	 * Drop the exit protection. This unblocks waiters which observed
+	 * FUTEX_STATE_EXITING to reevaluate the state.
+	 */
+	mutex_unlock(&tsk->futex_exit_mutex);
+}
+
+void futex_exec_release(struct task_struct *tsk)
+{
+	/*
+	 * The state handling is done for consistency, but in the case of
+	 * exec() there is no way to prevent further damage as the PID stays
+	 * the same. But for the unlikely and arguably buggy case that a
+	 * futex is held on exec(), this provides at least as much state
+	 * consistency protection which is possible.
+	 */
+	futex_cleanup_begin(tsk);
+	futex_cleanup(tsk);
+	/*
+	 * Reset the state to FUTEX_STATE_OK. The task is alive and about
+	 * exec a new binary.
+	 */
+	futex_cleanup_end(tsk, FUTEX_STATE_OK);
+}
+
+void futex_exit_release(struct task_struct *tsk)
+{
+	futex_cleanup_begin(tsk);
+	futex_cleanup(tsk);
+	futex_cleanup_end(tsk, FUTEX_STATE_DEAD);
+}
+
+static int __init futex_init(void)
+{
+	unsigned int futex_shift;
+	unsigned long i;
+
+#if CONFIG_BASE_SMALL
+	futex_hashsize = 16;
+#else
+	futex_hashsize = roundup_pow_of_two(256 * num_possible_cpus());
+#endif
+
+	futex_queues = alloc_large_system_hash("futex", sizeof(*futex_queues),
+					       futex_hashsize, 0,
+					       futex_hashsize < 256 ? HASH_SMALL : 0,
+					       &futex_shift, NULL,
+					       futex_hashsize, futex_hashsize);
+	futex_hashsize = 1UL << futex_shift;
+
+	for (i = 0; i < futex_hashsize; i++) {
+		atomic_set(&futex_queues[i].waiters, 0);
+		plist_head_init(&futex_queues[i].chain);
+		spin_lock_init(&futex_queues[i].lock);
+	}
+
+	return 0;
+}
+core_initcall(futex_init);
diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h
new file mode 100644
index 000000000..b5379c0e6
--- /dev/null
+++ b/kernel/futex/futex.h
@@ -0,0 +1,294 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _FUTEX_H
+#define _FUTEX_H
+
+#include <linux/futex.h>
+#include <linux/rtmutex.h>
+#include <linux/sched/wake_q.h>
+
+#ifdef CONFIG_PREEMPT_RT
+#include <linux/rcuwait.h>
+#endif
+
+#include <asm/futex.h>
+
+/*
+ * Futex flags used to encode options to functions and preserve them across
+ * restarts.
+ */
+#ifdef CONFIG_MMU
+# define FLAGS_SHARED		0x01
+#else
+/*
+ * NOMMU does not have per process address space. Let the compiler optimize
+ * code away.
+ */
+# define FLAGS_SHARED		0x00
+#endif
+#define FLAGS_CLOCKRT		0x02
+#define FLAGS_HAS_TIMEOUT	0x04
+
+#ifdef CONFIG_FAIL_FUTEX
+extern bool should_fail_futex(bool fshared);
+#else
+static inline bool should_fail_futex(bool fshared)
+{
+	return false;
+}
+#endif
+
+/*
+ * Hash buckets are shared by all the futex_keys that hash to the same
+ * location.  Each key may have multiple futex_q structures, one for each task
+ * waiting on a futex.
+ */
+struct futex_hash_bucket {
+	atomic_t waiters;
+	spinlock_t lock;
+	struct plist_head chain;
+} ____cacheline_aligned_in_smp;
+
+/*
+ * Priority Inheritance state:
+ */
+struct futex_pi_state {
+	/*
+	 * list of 'owned' pi_state instances - these have to be
+	 * cleaned up in do_exit() if the task exits prematurely:
+	 */
+	struct list_head list;
+
+	/*
+	 * The PI object:
+	 */
+	struct rt_mutex_base pi_mutex;
+
+	struct task_struct *owner;
+	refcount_t refcount;
+
+	union futex_key key;
+} __randomize_layout;
+
+/**
+ * struct futex_q - The hashed futex queue entry, one per waiting task
+ * @list:		priority-sorted list of tasks waiting on this futex
+ * @task:		the task waiting on the futex
+ * @lock_ptr:		the hash bucket lock
+ * @key:		the key the futex is hashed on
+ * @pi_state:		optional priority inheritance state
+ * @rt_waiter:		rt_waiter storage for use with requeue_pi
+ * @requeue_pi_key:	the requeue_pi target futex key
+ * @bitset:		bitset for the optional bitmasked wakeup
+ * @requeue_state:	State field for futex_requeue_pi()
+ * @requeue_wait:	RCU wait for futex_requeue_pi() (RT only)
+ *
+ * We use this hashed waitqueue, instead of a normal wait_queue_entry_t, so
+ * we can wake only the relevant ones (hashed queues may be shared).
+ *
+ * A futex_q has a woken state, just like tasks have TASK_RUNNING.
+ * It is considered woken when plist_node_empty(&q->list) || q->lock_ptr == 0.
+ * The order of wakeup is always to make the first condition true, then
+ * the second.
+ *
+ * PI futexes are typically woken before they are removed from the hash list via
+ * the rt_mutex code. See futex_unqueue_pi().
+ */
+struct futex_q {
+	struct plist_node list;
+
+	struct task_struct *task;
+	spinlock_t *lock_ptr;
+	union futex_key key;
+	struct futex_pi_state *pi_state;
+	struct rt_mutex_waiter *rt_waiter;
+	union futex_key *requeue_pi_key;
+	u32 bitset;
+	atomic_t requeue_state;
+#ifdef CONFIG_PREEMPT_RT
+	struct rcuwait requeue_wait;
+#endif
+} __randomize_layout;
+
+extern const struct futex_q futex_q_init;
+
+enum futex_access {
+	FUTEX_READ,
+	FUTEX_WRITE
+};
+
+extern int get_futex_key(u32 __user *uaddr, bool fshared, union futex_key *key,
+			 enum futex_access rw);
+
+extern struct hrtimer_sleeper *
+futex_setup_timer(ktime_t *time, struct hrtimer_sleeper *timeout,
+		  int flags, u64 range_ns);
+
+extern struct futex_hash_bucket *futex_hash(union futex_key *key);
+
+/**
+ * futex_match - Check whether two futex keys are equal
+ * @key1:	Pointer to key1
+ * @key2:	Pointer to key2
+ *
+ * Return 1 if two futex_keys are equal, 0 otherwise.
+ */
+static inline int futex_match(union futex_key *key1, union futex_key *key2)
+{
+	return (key1 && key2
+		&& key1->both.word == key2->both.word
+		&& key1->both.ptr == key2->both.ptr
+		&& key1->both.offset == key2->both.offset);
+}
+
+extern int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags,
+			    struct futex_q *q, struct futex_hash_bucket **hb);
+extern void futex_wait_queue(struct futex_hash_bucket *hb, struct futex_q *q,
+				   struct hrtimer_sleeper *timeout);
+extern void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q);
+
+extern int fault_in_user_writeable(u32 __user *uaddr);
+extern int futex_cmpxchg_value_locked(u32 *curval, u32 __user *uaddr, u32 uval, u32 newval);
+extern int futex_get_value_locked(u32 *dest, u32 __user *from);
+extern struct futex_q *futex_top_waiter(struct futex_hash_bucket *hb, union futex_key *key);
+
+extern void __futex_unqueue(struct futex_q *q);
+extern void __futex_queue(struct futex_q *q, struct futex_hash_bucket *hb);
+extern int futex_unqueue(struct futex_q *q);
+
+/**
+ * futex_queue() - Enqueue the futex_q on the futex_hash_bucket
+ * @q:	The futex_q to enqueue
+ * @hb:	The destination hash bucket
+ *
+ * The hb->lock must be held by the caller, and is released here. A call to
+ * futex_queue() is typically paired with exactly one call to futex_unqueue().  The
+ * exceptions involve the PI related operations, which may use futex_unqueue_pi()
+ * or nothing if the unqueue is done as part of the wake process and the unqueue
+ * state is implicit in the state of woken task (see futex_wait_requeue_pi() for
+ * an example).
+ */
+static inline void futex_queue(struct futex_q *q, struct futex_hash_bucket *hb)
+	__releases(&hb->lock)
+{
+	__futex_queue(q, hb);
+	spin_unlock(&hb->lock);
+}
+
+extern void futex_unqueue_pi(struct futex_q *q);
+
+extern void wait_for_owner_exiting(int ret, struct task_struct *exiting);
+
+/*
+ * Reflects a new waiter being added to the waitqueue.
+ */
+static inline void futex_hb_waiters_inc(struct futex_hash_bucket *hb)
+{
+#ifdef CONFIG_SMP
+	atomic_inc(&hb->waiters);
+	/*
+	 * Full barrier (A), see the ordering comment above.
+	 */
+	smp_mb__after_atomic();
+#endif
+}
+
+/*
+ * Reflects a waiter being removed from the waitqueue by wakeup
+ * paths.
+ */
+static inline void futex_hb_waiters_dec(struct futex_hash_bucket *hb)
+{
+#ifdef CONFIG_SMP
+	atomic_dec(&hb->waiters);
+#endif
+}
+
+static inline int futex_hb_waiters_pending(struct futex_hash_bucket *hb)
+{
+#ifdef CONFIG_SMP
+	/*
+	 * Full barrier (B), see the ordering comment above.
+	 */
+	smp_mb();
+	return atomic_read(&hb->waiters);
+#else
+	return 1;
+#endif
+}
+
+extern struct futex_hash_bucket *futex_q_lock(struct futex_q *q);
+extern void futex_q_unlock(struct futex_hash_bucket *hb);
+
+
+extern int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb,
+				union futex_key *key,
+				struct futex_pi_state **ps,
+				struct task_struct *task,
+				struct task_struct **exiting,
+				int set_waiters);
+
+extern int refill_pi_state_cache(void);
+extern void get_pi_state(struct futex_pi_state *pi_state);
+extern void put_pi_state(struct futex_pi_state *pi_state);
+extern int fixup_pi_owner(u32 __user *uaddr, struct futex_q *q, int locked);
+
+/*
+ * Express the locking dependencies for lockdep:
+ */
+static inline void
+double_lock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2)
+{
+	if (hb1 > hb2)
+		swap(hb1, hb2);
+
+	spin_lock(&hb1->lock);
+	if (hb1 != hb2)
+		spin_lock_nested(&hb2->lock, SINGLE_DEPTH_NESTING);
+}
+
+static inline void
+double_unlock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2)
+{
+	spin_unlock(&hb1->lock);
+	if (hb1 != hb2)
+		spin_unlock(&hb2->lock);
+}
+
+/* syscalls */
+
+extern int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, u32
+				 val, ktime_t *abs_time, u32 bitset, u32 __user
+				 *uaddr2);
+
+extern int futex_requeue(u32 __user *uaddr1, unsigned int flags,
+			 u32 __user *uaddr2, int nr_wake, int nr_requeue,
+			 u32 *cmpval, int requeue_pi);
+
+extern int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val,
+		      ktime_t *abs_time, u32 bitset);
+
+/**
+ * struct futex_vector - Auxiliary struct for futex_waitv()
+ * @w: Userspace provided data
+ * @q: Kernel side data
+ *
+ * Struct used to build an array with all data need for futex_waitv()
+ */
+struct futex_vector {
+	struct futex_waitv w;
+	struct futex_q q;
+};
+
+extern int futex_wait_multiple(struct futex_vector *vs, unsigned int count,
+			       struct hrtimer_sleeper *to);
+
+extern int futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset);
+
+extern int futex_wake_op(u32 __user *uaddr1, unsigned int flags,
+			 u32 __user *uaddr2, int nr_wake, int nr_wake2, int op);
+
+extern int futex_unlock_pi(u32 __user *uaddr, unsigned int flags);
+
+extern int futex_lock_pi(u32 __user *uaddr, unsigned int flags, ktime_t *time, int trylock);
+
+#endif /* _FUTEX_H */
diff --git a/kernel/futex/pi.c b/kernel/futex/pi.c
new file mode 100644
index 000000000..ce2889f12
--- /dev/null
+++ b/kernel/futex/pi.c
@@ -0,0 +1,1233 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/slab.h>
+#include <linux/sched/task.h>
+
+#include "futex.h"
+#include "../locking/rtmutex_common.h"
+
+/*
+ * PI code:
+ */
+int refill_pi_state_cache(void)
+{
+	struct futex_pi_state *pi_state;
+
+	if (likely(current->pi_state_cache))
+		return 0;
+
+	pi_state = kzalloc(sizeof(*pi_state), GFP_KERNEL);
+
+	if (!pi_state)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&pi_state->list);
+	/* pi_mutex gets initialized later */
+	pi_state->owner = NULL;
+	refcount_set(&pi_state->refcount, 1);
+	pi_state->key = FUTEX_KEY_INIT;
+
+	current->pi_state_cache = pi_state;
+
+	return 0;
+}
+
+static struct futex_pi_state *alloc_pi_state(void)
+{
+	struct futex_pi_state *pi_state = current->pi_state_cache;
+
+	WARN_ON(!pi_state);
+	current->pi_state_cache = NULL;
+
+	return pi_state;
+}
+
+static void pi_state_update_owner(struct futex_pi_state *pi_state,
+				  struct task_struct *new_owner)
+{
+	struct task_struct *old_owner = pi_state->owner;
+
+	lockdep_assert_held(&pi_state->pi_mutex.wait_lock);
+
+	if (old_owner) {
+		raw_spin_lock(&old_owner->pi_lock);
+		WARN_ON(list_empty(&pi_state->list));
+		list_del_init(&pi_state->list);
+		raw_spin_unlock(&old_owner->pi_lock);
+	}
+
+	if (new_owner) {
+		raw_spin_lock(&new_owner->pi_lock);
+		WARN_ON(!list_empty(&pi_state->list));
+		list_add(&pi_state->list, &new_owner->pi_state_list);
+		pi_state->owner = new_owner;
+		raw_spin_unlock(&new_owner->pi_lock);
+	}
+}
+
+void get_pi_state(struct futex_pi_state *pi_state)
+{
+	WARN_ON_ONCE(!refcount_inc_not_zero(&pi_state->refcount));
+}
+
+/*
+ * Drops a reference to the pi_state object and frees or caches it
+ * when the last reference is gone.
+ */
+void put_pi_state(struct futex_pi_state *pi_state)
+{
+	if (!pi_state)
+		return;
+
+	if (!refcount_dec_and_test(&pi_state->refcount))
+		return;
+
+	/*
+	 * If pi_state->owner is NULL, the owner is most probably dying
+	 * and has cleaned up the pi_state already
+	 */
+	if (pi_state->owner) {
+		unsigned long flags;
+
+		raw_spin_lock_irqsave(&pi_state->pi_mutex.wait_lock, flags);
+		pi_state_update_owner(pi_state, NULL);
+		rt_mutex_proxy_unlock(&pi_state->pi_mutex);
+		raw_spin_unlock_irqrestore(&pi_state->pi_mutex.wait_lock, flags);
+	}
+
+	if (current->pi_state_cache) {
+		kfree(pi_state);
+	} else {
+		/*
+		 * pi_state->list is already empty.
+		 * clear pi_state->owner.
+		 * refcount is at 0 - put it back to 1.
+		 */
+		pi_state->owner = NULL;
+		refcount_set(&pi_state->refcount, 1);
+		current->pi_state_cache = pi_state;
+	}
+}
+
+/*
+ * We need to check the following states:
+ *
+ *      Waiter | pi_state | pi->owner | uTID      | uODIED | ?
+ *
+ * [1]  NULL   | ---      | ---       | 0         | 0/1    | Valid
+ * [2]  NULL   | ---      | ---       | >0        | 0/1    | Valid
+ *
+ * [3]  Found  | NULL     | --        | Any       | 0/1    | Invalid
+ *
+ * [4]  Found  | Found    | NULL      | 0         | 1      | Valid
+ * [5]  Found  | Found    | NULL      | >0        | 1      | Invalid
+ *
+ * [6]  Found  | Found    | task      | 0         | 1      | Valid
+ *
+ * [7]  Found  | Found    | NULL      | Any       | 0      | Invalid
+ *
+ * [8]  Found  | Found    | task      | ==taskTID | 0/1    | Valid
+ * [9]  Found  | Found    | task      | 0         | 0      | Invalid
+ * [10] Found  | Found    | task      | !=taskTID | 0/1    | Invalid
+ *
+ * [1]	Indicates that the kernel can acquire the futex atomically. We
+ *	came here due to a stale FUTEX_WAITERS/FUTEX_OWNER_DIED bit.
+ *
+ * [2]	Valid, if TID does not belong to a kernel thread. If no matching
+ *      thread is found then it indicates that the owner TID has died.
+ *
+ * [3]	Invalid. The waiter is queued on a non PI futex
+ *
+ * [4]	Valid state after exit_robust_list(), which sets the user space
+ *	value to FUTEX_WAITERS | FUTEX_OWNER_DIED.
+ *
+ * [5]	The user space value got manipulated between exit_robust_list()
+ *	and exit_pi_state_list()
+ *
+ * [6]	Valid state after exit_pi_state_list() which sets the new owner in
+ *	the pi_state but cannot access the user space value.
+ *
+ * [7]	pi_state->owner can only be NULL when the OWNER_DIED bit is set.
+ *
+ * [8]	Owner and user space value match
+ *
+ * [9]	There is no transient state which sets the user space TID to 0
+ *	except exit_robust_list(), but this is indicated by the
+ *	FUTEX_OWNER_DIED bit. See [4]
+ *
+ * [10] There is no transient state which leaves owner and user space
+ *	TID out of sync. Except one error case where the kernel is denied
+ *	write access to the user address, see fixup_pi_state_owner().
+ *
+ *
+ * Serialization and lifetime rules:
+ *
+ * hb->lock:
+ *
+ *	hb -> futex_q, relation
+ *	futex_q -> pi_state, relation
+ *
+ *	(cannot be raw because hb can contain arbitrary amount
+ *	 of futex_q's)
+ *
+ * pi_mutex->wait_lock:
+ *
+ *	{uval, pi_state}
+ *
+ *	(and pi_mutex 'obviously')
+ *
+ * p->pi_lock:
+ *
+ *	p->pi_state_list -> pi_state->list, relation
+ *	pi_mutex->owner -> pi_state->owner, relation
+ *
+ * pi_state->refcount:
+ *
+ *	pi_state lifetime
+ *
+ *
+ * Lock order:
+ *
+ *   hb->lock
+ *     pi_mutex->wait_lock
+ *       p->pi_lock
+ *
+ */
+
+/*
+ * Validate that the existing waiter has a pi_state and sanity check
+ * the pi_state against the user space value. If correct, attach to
+ * it.
+ */
+static int attach_to_pi_state(u32 __user *uaddr, u32 uval,
+			      struct futex_pi_state *pi_state,
+			      struct futex_pi_state **ps)
+{
+	pid_t pid = uval & FUTEX_TID_MASK;
+	u32 uval2;
+	int ret;
+
+	/*
+	 * Userspace might have messed up non-PI and PI futexes [3]
+	 */
+	if (unlikely(!pi_state))
+		return -EINVAL;
+
+	/*
+	 * We get here with hb->lock held, and having found a
+	 * futex_top_waiter(). This means that futex_lock_pi() of said futex_q
+	 * has dropped the hb->lock in between futex_queue() and futex_unqueue_pi(),
+	 * which in turn means that futex_lock_pi() still has a reference on
+	 * our pi_state.
+	 *
+	 * The waiter holding a reference on @pi_state also protects against
+	 * the unlocked put_pi_state() in futex_unlock_pi(), futex_lock_pi()
+	 * and futex_wait_requeue_pi() as it cannot go to 0 and consequently
+	 * free pi_state before we can take a reference ourselves.
+	 */
+	WARN_ON(!refcount_read(&pi_state->refcount));
+
+	/*
+	 * Now that we have a pi_state, we can acquire wait_lock
+	 * and do the state validation.
+	 */
+	raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+
+	/*
+	 * Since {uval, pi_state} is serialized by wait_lock, and our current
+	 * uval was read without holding it, it can have changed. Verify it
+	 * still is what we expect it to be, otherwise retry the entire
+	 * operation.
+	 */
+	if (futex_get_value_locked(&uval2, uaddr))
+		goto out_efault;
+
+	if (uval != uval2)
+		goto out_eagain;
+
+	/*
+	 * Handle the owner died case:
+	 */
+	if (uval & FUTEX_OWNER_DIED) {
+		/*
+		 * exit_pi_state_list sets owner to NULL and wakes the
+		 * topmost waiter. The task which acquires the
+		 * pi_state->rt_mutex will fixup owner.
+		 */
+		if (!pi_state->owner) {
+			/*
+			 * No pi state owner, but the user space TID
+			 * is not 0. Inconsistent state. [5]
+			 */
+			if (pid)
+				goto out_einval;
+			/*
+			 * Take a ref on the state and return success. [4]
+			 */
+			goto out_attach;
+		}
+
+		/*
+		 * If TID is 0, then either the dying owner has not
+		 * yet executed exit_pi_state_list() or some waiter
+		 * acquired the rtmutex in the pi state, but did not
+		 * yet fixup the TID in user space.
+		 *
+		 * Take a ref on the state and return success. [6]
+		 */
+		if (!pid)
+			goto out_attach;
+	} else {
+		/*
+		 * If the owner died bit is not set, then the pi_state
+		 * must have an owner. [7]
+		 */
+		if (!pi_state->owner)
+			goto out_einval;
+	}
+
+	/*
+	 * Bail out if user space manipulated the futex value. If pi
+	 * state exists then the owner TID must be the same as the
+	 * user space TID. [9/10]
+	 */
+	if (pid != task_pid_vnr(pi_state->owner))
+		goto out_einval;
+
+out_attach:
+	get_pi_state(pi_state);
+	raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
+	*ps = pi_state;
+	return 0;
+
+out_einval:
+	ret = -EINVAL;
+	goto out_error;
+
+out_eagain:
+	ret = -EAGAIN;
+	goto out_error;
+
+out_efault:
+	ret = -EFAULT;
+	goto out_error;
+
+out_error:
+	raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
+	return ret;
+}
+
+static int handle_exit_race(u32 __user *uaddr, u32 uval,
+			    struct task_struct *tsk)
+{
+	u32 uval2;
+
+	/*
+	 * If the futex exit state is not yet FUTEX_STATE_DEAD, tell the
+	 * caller that the alleged owner is busy.
+	 */
+	if (tsk && tsk->futex_state != FUTEX_STATE_DEAD)
+		return -EBUSY;
+
+	/*
+	 * Reread the user space value to handle the following situation:
+	 *
+	 * CPU0				CPU1
+	 *
+	 * sys_exit()			sys_futex()
+	 *  do_exit()			 futex_lock_pi()
+	 *                                futex_lock_pi_atomic()
+	 *   exit_signals(tsk)		    No waiters:
+	 *    tsk->flags |= PF_EXITING;	    *uaddr == 0x00000PID
+	 *  mm_release(tsk)		    Set waiter bit
+	 *   exit_robust_list(tsk) {	    *uaddr = 0x80000PID;
+	 *      Set owner died		    attach_to_pi_owner() {
+	 *    *uaddr = 0xC0000000;	     tsk = get_task(PID);
+	 *   }				     if (!tsk->flags & PF_EXITING) {
+	 *  ...				       attach();
+	 *  tsk->futex_state =               } else {
+	 *	FUTEX_STATE_DEAD;              if (tsk->futex_state !=
+	 *					  FUTEX_STATE_DEAD)
+	 *				         return -EAGAIN;
+	 *				       return -ESRCH; <--- FAIL
+	 *				     }
+	 *
+	 * Returning ESRCH unconditionally is wrong here because the
+	 * user space value has been changed by the exiting task.
+	 *
+	 * The same logic applies to the case where the exiting task is
+	 * already gone.
+	 */
+	if (futex_get_value_locked(&uval2, uaddr))
+		return -EFAULT;
+
+	/* If the user space value has changed, try again. */
+	if (uval2 != uval)
+		return -EAGAIN;
+
+	/*
+	 * The exiting task did not have a robust list, the robust list was
+	 * corrupted or the user space value in *uaddr is simply bogus.
+	 * Give up and tell user space.
+	 */
+	return -ESRCH;
+}
+
+static void __attach_to_pi_owner(struct task_struct *p, union futex_key *key,
+				 struct futex_pi_state **ps)
+{
+	/*
+	 * No existing pi state. First waiter. [2]
+	 *
+	 * This creates pi_state, we have hb->lock held, this means nothing can
+	 * observe this state, wait_lock is irrelevant.
+	 */
+	struct futex_pi_state *pi_state = alloc_pi_state();
+
+	/*
+	 * Initialize the pi_mutex in locked state and make @p
+	 * the owner of it:
+	 */
+	rt_mutex_init_proxy_locked(&pi_state->pi_mutex, p);
+
+	/* Store the key for possible exit cleanups: */
+	pi_state->key = *key;
+
+	WARN_ON(!list_empty(&pi_state->list));
+	list_add(&pi_state->list, &p->pi_state_list);
+	/*
+	 * Assignment without holding pi_state->pi_mutex.wait_lock is safe
+	 * because there is no concurrency as the object is not published yet.
+	 */
+	pi_state->owner = p;
+
+	*ps = pi_state;
+}
+/*
+ * Lookup the task for the TID provided from user space and attach to
+ * it after doing proper sanity checks.
+ */
+static int attach_to_pi_owner(u32 __user *uaddr, u32 uval, union futex_key *key,
+			      struct futex_pi_state **ps,
+			      struct task_struct **exiting)
+{
+	pid_t pid = uval & FUTEX_TID_MASK;
+	struct task_struct *p;
+
+	/*
+	 * We are the first waiter - try to look up the real owner and attach
+	 * the new pi_state to it, but bail out when TID = 0 [1]
+	 *
+	 * The !pid check is paranoid. None of the call sites should end up
+	 * with pid == 0, but better safe than sorry. Let the caller retry
+	 */
+	if (!pid)
+		return -EAGAIN;
+	p = find_get_task_by_vpid(pid);
+	if (!p)
+		return handle_exit_race(uaddr, uval, NULL);
+
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		put_task_struct(p);
+		return -EPERM;
+	}
+
+	/*
+	 * We need to look at the task state to figure out, whether the
+	 * task is exiting. To protect against the change of the task state
+	 * in futex_exit_release(), we do this protected by p->pi_lock:
+	 */
+	raw_spin_lock_irq(&p->pi_lock);
+	if (unlikely(p->futex_state != FUTEX_STATE_OK)) {
+		/*
+		 * The task is on the way out. When the futex state is
+		 * FUTEX_STATE_DEAD, we know that the task has finished
+		 * the cleanup:
+		 */
+		int ret = handle_exit_race(uaddr, uval, p);
+
+		raw_spin_unlock_irq(&p->pi_lock);
+		/*
+		 * If the owner task is between FUTEX_STATE_EXITING and
+		 * FUTEX_STATE_DEAD then store the task pointer and keep
+		 * the reference on the task struct. The calling code will
+		 * drop all locks, wait for the task to reach
+		 * FUTEX_STATE_DEAD and then drop the refcount. This is
+		 * required to prevent a live lock when the current task
+		 * preempted the exiting task between the two states.
+		 */
+		if (ret == -EBUSY)
+			*exiting = p;
+		else
+			put_task_struct(p);
+		return ret;
+	}
+
+	__attach_to_pi_owner(p, key, ps);
+	raw_spin_unlock_irq(&p->pi_lock);
+
+	put_task_struct(p);
+
+	return 0;
+}
+
+static int lock_pi_update_atomic(u32 __user *uaddr, u32 uval, u32 newval)
+{
+	int err;
+	u32 curval;
+
+	if (unlikely(should_fail_futex(true)))
+		return -EFAULT;
+
+	err = futex_cmpxchg_value_locked(&curval, uaddr, uval, newval);
+	if (unlikely(err))
+		return err;
+
+	/* If user space value changed, let the caller retry */
+	return curval != uval ? -EAGAIN : 0;
+}
+
+/**
+ * futex_lock_pi_atomic() - Atomic work required to acquire a pi aware futex
+ * @uaddr:		the pi futex user address
+ * @hb:			the pi futex hash bucket
+ * @key:		the futex key associated with uaddr and hb
+ * @ps:			the pi_state pointer where we store the result of the
+ *			lookup
+ * @task:		the task to perform the atomic lock work for.  This will
+ *			be "current" except in the case of requeue pi.
+ * @exiting:		Pointer to store the task pointer of the owner task
+ *			which is in the middle of exiting
+ * @set_waiters:	force setting the FUTEX_WAITERS bit (1) or not (0)
+ *
+ * Return:
+ *  -  0 - ready to wait;
+ *  -  1 - acquired the lock;
+ *  - <0 - error
+ *
+ * The hb->lock must be held by the caller.
+ *
+ * @exiting is only set when the return value is -EBUSY. If so, this holds
+ * a refcount on the exiting task on return and the caller needs to drop it
+ * after waiting for the exit to complete.
+ */
+int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb,
+			 union futex_key *key,
+			 struct futex_pi_state **ps,
+			 struct task_struct *task,
+			 struct task_struct **exiting,
+			 int set_waiters)
+{
+	u32 uval, newval, vpid = task_pid_vnr(task);
+	struct futex_q *top_waiter;
+	int ret;
+
+	/*
+	 * Read the user space value first so we can validate a few
+	 * things before proceeding further.
+	 */
+	if (futex_get_value_locked(&uval, uaddr))
+		return -EFAULT;
+
+	if (unlikely(should_fail_futex(true)))
+		return -EFAULT;
+
+	/*
+	 * Detect deadlocks.
+	 */
+	if ((unlikely((uval & FUTEX_TID_MASK) == vpid)))
+		return -EDEADLK;
+
+	if ((unlikely(should_fail_futex(true))))
+		return -EDEADLK;
+
+	/*
+	 * Lookup existing state first. If it exists, try to attach to
+	 * its pi_state.
+	 */
+	top_waiter = futex_top_waiter(hb, key);
+	if (top_waiter)
+		return attach_to_pi_state(uaddr, uval, top_waiter->pi_state, ps);
+
+	/*
+	 * No waiter and user TID is 0. We are here because the
+	 * waiters or the owner died bit is set or called from
+	 * requeue_cmp_pi or for whatever reason something took the
+	 * syscall.
+	 */
+	if (!(uval & FUTEX_TID_MASK)) {
+		/*
+		 * We take over the futex. No other waiters and the user space
+		 * TID is 0. We preserve the owner died bit.
+		 */
+		newval = uval & FUTEX_OWNER_DIED;
+		newval |= vpid;
+
+		/* The futex requeue_pi code can enforce the waiters bit */
+		if (set_waiters)
+			newval |= FUTEX_WAITERS;
+
+		ret = lock_pi_update_atomic(uaddr, uval, newval);
+		if (ret)
+			return ret;
+
+		/*
+		 * If the waiter bit was requested the caller also needs PI
+		 * state attached to the new owner of the user space futex.
+		 *
+		 * @task is guaranteed to be alive and it cannot be exiting
+		 * because it is either sleeping or waiting in
+		 * futex_requeue_pi_wakeup_sync().
+		 *
+		 * No need to do the full attach_to_pi_owner() exercise
+		 * because @task is known and valid.
+		 */
+		if (set_waiters) {
+			raw_spin_lock_irq(&task->pi_lock);
+			__attach_to_pi_owner(task, key, ps);
+			raw_spin_unlock_irq(&task->pi_lock);
+		}
+		return 1;
+	}
+
+	/*
+	 * First waiter. Set the waiters bit before attaching ourself to
+	 * the owner. If owner tries to unlock, it will be forced into
+	 * the kernel and blocked on hb->lock.
+	 */
+	newval = uval | FUTEX_WAITERS;
+	ret = lock_pi_update_atomic(uaddr, uval, newval);
+	if (ret)
+		return ret;
+	/*
+	 * If the update of the user space value succeeded, we try to
+	 * attach to the owner. If that fails, no harm done, we only
+	 * set the FUTEX_WAITERS bit in the user space variable.
+	 */
+	return attach_to_pi_owner(uaddr, newval, key, ps, exiting);
+}
+
+/*
+ * Caller must hold a reference on @pi_state.
+ */
+static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_state)
+{
+	struct rt_mutex_waiter *top_waiter;
+	struct task_struct *new_owner;
+	bool postunlock = false;
+	DEFINE_RT_WAKE_Q(wqh);
+	u32 curval, newval;
+	int ret = 0;
+
+	top_waiter = rt_mutex_top_waiter(&pi_state->pi_mutex);
+	if (WARN_ON_ONCE(!top_waiter)) {
+		/*
+		 * As per the comment in futex_unlock_pi() this should not happen.
+		 *
+		 * When this happens, give up our locks and try again, giving
+		 * the futex_lock_pi() instance time to complete, either by
+		 * waiting on the rtmutex or removing itself from the futex
+		 * queue.
+		 */
+		ret = -EAGAIN;
+		goto out_unlock;
+	}
+
+	new_owner = top_waiter->task;
+
+	/*
+	 * We pass it to the next owner. The WAITERS bit is always kept
+	 * enabled while there is PI state around. We cleanup the owner
+	 * died bit, because we are the owner.
+	 */
+	newval = FUTEX_WAITERS | task_pid_vnr(new_owner);
+
+	if (unlikely(should_fail_futex(true))) {
+		ret = -EFAULT;
+		goto out_unlock;
+	}
+
+	ret = futex_cmpxchg_value_locked(&curval, uaddr, uval, newval);
+	if (!ret && (curval != uval)) {
+		/*
+		 * If a unconditional UNLOCK_PI operation (user space did not
+		 * try the TID->0 transition) raced with a waiter setting the
+		 * FUTEX_WAITERS flag between get_user() and locking the hash
+		 * bucket lock, retry the operation.
+		 */
+		if ((FUTEX_TID_MASK & curval) == uval)
+			ret = -EAGAIN;
+		else
+			ret = -EINVAL;
+	}
+
+	if (!ret) {
+		/*
+		 * This is a point of no return; once we modified the uval
+		 * there is no going back and subsequent operations must
+		 * not fail.
+		 */
+		pi_state_update_owner(pi_state, new_owner);
+		postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wqh);
+	}
+
+out_unlock:
+	raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
+
+	if (postunlock)
+		rt_mutex_postunlock(&wqh);
+
+	return ret;
+}
+
+static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
+				  struct task_struct *argowner)
+{
+	struct futex_pi_state *pi_state = q->pi_state;
+	struct task_struct *oldowner, *newowner;
+	u32 uval, curval, newval, newtid;
+	int err = 0;
+
+	oldowner = pi_state->owner;
+
+	/*
+	 * We are here because either:
+	 *
+	 *  - we stole the lock and pi_state->owner needs updating to reflect
+	 *    that (@argowner == current),
+	 *
+	 * or:
+	 *
+	 *  - someone stole our lock and we need to fix things to point to the
+	 *    new owner (@argowner == NULL).
+	 *
+	 * Either way, we have to replace the TID in the user space variable.
+	 * This must be atomic as we have to preserve the owner died bit here.
+	 *
+	 * Note: We write the user space value _before_ changing the pi_state
+	 * because we can fault here. Imagine swapped out pages or a fork
+	 * that marked all the anonymous memory readonly for cow.
+	 *
+	 * Modifying pi_state _before_ the user space value would leave the
+	 * pi_state in an inconsistent state when we fault here, because we
+	 * need to drop the locks to handle the fault. This might be observed
+	 * in the PID checks when attaching to PI state .
+	 */
+retry:
+	if (!argowner) {
+		if (oldowner != current) {
+			/*
+			 * We raced against a concurrent self; things are
+			 * already fixed up. Nothing to do.
+			 */
+			return 0;
+		}
+
+		if (__rt_mutex_futex_trylock(&pi_state->pi_mutex)) {
+			/* We got the lock. pi_state is correct. Tell caller. */
+			return 1;
+		}
+
+		/*
+		 * The trylock just failed, so either there is an owner or
+		 * there is a higher priority waiter than this one.
+		 */
+		newowner = rt_mutex_owner(&pi_state->pi_mutex);
+		/*
+		 * If the higher priority waiter has not yet taken over the
+		 * rtmutex then newowner is NULL. We can't return here with
+		 * that state because it's inconsistent vs. the user space
+		 * state. So drop the locks and try again. It's a valid
+		 * situation and not any different from the other retry
+		 * conditions.
+		 */
+		if (unlikely(!newowner)) {
+			err = -EAGAIN;
+			goto handle_err;
+		}
+	} else {
+		WARN_ON_ONCE(argowner != current);
+		if (oldowner == current) {
+			/*
+			 * We raced against a concurrent self; things are
+			 * already fixed up. Nothing to do.
+			 */
+			return 1;
+		}
+		newowner = argowner;
+	}
+
+	newtid = task_pid_vnr(newowner) | FUTEX_WAITERS;
+	/* Owner died? */
+	if (!pi_state->owner)
+		newtid |= FUTEX_OWNER_DIED;
+
+	err = futex_get_value_locked(&uval, uaddr);
+	if (err)
+		goto handle_err;
+
+	for (;;) {
+		newval = (uval & FUTEX_OWNER_DIED) | newtid;
+
+		err = futex_cmpxchg_value_locked(&curval, uaddr, uval, newval);
+		if (err)
+			goto handle_err;
+
+		if (curval == uval)
+			break;
+		uval = curval;
+	}
+
+	/*
+	 * We fixed up user space. Now we need to fix the pi_state
+	 * itself.
+	 */
+	pi_state_update_owner(pi_state, newowner);
+
+	return argowner == current;
+
+	/*
+	 * In order to reschedule or handle a page fault, we need to drop the
+	 * locks here. In the case of a fault, this gives the other task
+	 * (either the highest priority waiter itself or the task which stole
+	 * the rtmutex) the chance to try the fixup of the pi_state. So once we
+	 * are back from handling the fault we need to check the pi_state after
+	 * reacquiring the locks and before trying to do another fixup. When
+	 * the fixup has been done already we simply return.
+	 *
+	 * Note: we hold both hb->lock and pi_mutex->wait_lock. We can safely
+	 * drop hb->lock since the caller owns the hb -> futex_q relation.
+	 * Dropping the pi_mutex->wait_lock requires the state revalidate.
+	 */
+handle_err:
+	raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
+	spin_unlock(q->lock_ptr);
+
+	switch (err) {
+	case -EFAULT:
+		err = fault_in_user_writeable(uaddr);
+		break;
+
+	case -EAGAIN:
+		cond_resched();
+		err = 0;
+		break;
+
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
+
+	spin_lock(q->lock_ptr);
+	raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+
+	/*
+	 * Check if someone else fixed it for us:
+	 */
+	if (pi_state->owner != oldowner)
+		return argowner == current;
+
+	/* Retry if err was -EAGAIN or the fault in succeeded */
+	if (!err)
+		goto retry;
+
+	/*
+	 * fault_in_user_writeable() failed so user state is immutable. At
+	 * best we can make the kernel state consistent but user state will
+	 * be most likely hosed and any subsequent unlock operation will be
+	 * rejected due to PI futex rule [10].
+	 *
+	 * Ensure that the rtmutex owner is also the pi_state owner despite
+	 * the user space value claiming something different. There is no
+	 * point in unlocking the rtmutex if current is the owner as it
+	 * would need to wait until the next waiter has taken the rtmutex
+	 * to guarantee consistent state. Keep it simple. Userspace asked
+	 * for this wreckaged state.
+	 *
+	 * The rtmutex has an owner - either current or some other
+	 * task. See the EAGAIN loop above.
+	 */
+	pi_state_update_owner(pi_state, rt_mutex_owner(&pi_state->pi_mutex));
+
+	return err;
+}
+
+static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
+				struct task_struct *argowner)
+{
+	struct futex_pi_state *pi_state = q->pi_state;
+	int ret;
+
+	lockdep_assert_held(q->lock_ptr);
+
+	raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+	ret = __fixup_pi_state_owner(uaddr, q, argowner);
+	raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
+	return ret;
+}
+
+/**
+ * fixup_pi_owner() - Post lock pi_state and corner case management
+ * @uaddr:	user address of the futex
+ * @q:		futex_q (contains pi_state and access to the rt_mutex)
+ * @locked:	if the attempt to take the rt_mutex succeeded (1) or not (0)
+ *
+ * After attempting to lock an rt_mutex, this function is called to cleanup
+ * the pi_state owner as well as handle race conditions that may allow us to
+ * acquire the lock. Must be called with the hb lock held.
+ *
+ * Return:
+ *  -  1 - success, lock taken;
+ *  -  0 - success, lock not taken;
+ *  - <0 - on error (-EFAULT)
+ */
+int fixup_pi_owner(u32 __user *uaddr, struct futex_q *q, int locked)
+{
+	if (locked) {
+		/*
+		 * Got the lock. We might not be the anticipated owner if we
+		 * did a lock-steal - fix up the PI-state in that case:
+		 *
+		 * Speculative pi_state->owner read (we don't hold wait_lock);
+		 * since we own the lock pi_state->owner == current is the
+		 * stable state, anything else needs more attention.
+		 */
+		if (q->pi_state->owner != current)
+			return fixup_pi_state_owner(uaddr, q, current);
+		return 1;
+	}
+
+	/*
+	 * If we didn't get the lock; check if anybody stole it from us. In
+	 * that case, we need to fix up the uval to point to them instead of
+	 * us, otherwise bad things happen. [10]
+	 *
+	 * Another speculative read; pi_state->owner == current is unstable
+	 * but needs our attention.
+	 */
+	if (q->pi_state->owner == current)
+		return fixup_pi_state_owner(uaddr, q, NULL);
+
+	/*
+	 * Paranoia check. If we did not take the lock, then we should not be
+	 * the owner of the rt_mutex. Warn and establish consistent state.
+	 */
+	if (WARN_ON_ONCE(rt_mutex_owner(&q->pi_state->pi_mutex) == current))
+		return fixup_pi_state_owner(uaddr, q, current);
+
+	return 0;
+}
+
+/*
+ * Userspace tried a 0 -> TID atomic transition of the futex value
+ * and failed. The kernel side here does the whole locking operation:
+ * if there are waiters then it will block as a consequence of relying
+ * on rt-mutexes, it does PI, etc. (Due to races the kernel might see
+ * a 0 value of the futex too.).
+ *
+ * Also serves as futex trylock_pi()'ing, and due semantics.
+ */
+int futex_lock_pi(u32 __user *uaddr, unsigned int flags, ktime_t *time, int trylock)
+{
+	struct hrtimer_sleeper timeout, *to;
+	struct task_struct *exiting = NULL;
+	struct rt_mutex_waiter rt_waiter;
+	struct futex_hash_bucket *hb;
+	struct futex_q q = futex_q_init;
+	int res, ret;
+
+	if (!IS_ENABLED(CONFIG_FUTEX_PI))
+		return -ENOSYS;
+
+	if (refill_pi_state_cache())
+		return -ENOMEM;
+
+	to = futex_setup_timer(time, &timeout, flags, 0);
+
+retry:
+	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key, FUTEX_WRITE);
+	if (unlikely(ret != 0))
+		goto out;
+
+retry_private:
+	hb = futex_q_lock(&q);
+
+	ret = futex_lock_pi_atomic(uaddr, hb, &q.key, &q.pi_state, current,
+				   &exiting, 0);
+	if (unlikely(ret)) {
+		/*
+		 * Atomic work succeeded and we got the lock,
+		 * or failed. Either way, we do _not_ block.
+		 */
+		switch (ret) {
+		case 1:
+			/* We got the lock. */
+			ret = 0;
+			goto out_unlock_put_key;
+		case -EFAULT:
+			goto uaddr_faulted;
+		case -EBUSY:
+		case -EAGAIN:
+			/*
+			 * Two reasons for this:
+			 * - EBUSY: Task is exiting and we just wait for the
+			 *   exit to complete.
+			 * - EAGAIN: The user space value changed.
+			 */
+			futex_q_unlock(hb);
+			/*
+			 * Handle the case where the owner is in the middle of
+			 * exiting. Wait for the exit to complete otherwise
+			 * this task might loop forever, aka. live lock.
+			 */
+			wait_for_owner_exiting(ret, exiting);
+			cond_resched();
+			goto retry;
+		default:
+			goto out_unlock_put_key;
+		}
+	}
+
+	WARN_ON(!q.pi_state);
+
+	/*
+	 * Only actually queue now that the atomic ops are done:
+	 */
+	__futex_queue(&q, hb);
+
+	if (trylock) {
+		ret = rt_mutex_futex_trylock(&q.pi_state->pi_mutex);
+		/* Fixup the trylock return value: */
+		ret = ret ? 0 : -EWOULDBLOCK;
+		goto no_block;
+	}
+
+	rt_mutex_init_waiter(&rt_waiter);
+
+	/*
+	 * On PREEMPT_RT, when hb->lock becomes an rt_mutex, we must not
+	 * hold it while doing rt_mutex_start_proxy(), because then it will
+	 * include hb->lock in the blocking chain, even through we'll not in
+	 * fact hold it while blocking. This will lead it to report -EDEADLK
+	 * and BUG when futex_unlock_pi() interleaves with this.
+	 *
+	 * Therefore acquire wait_lock while holding hb->lock, but drop the
+	 * latter before calling __rt_mutex_start_proxy_lock(). This
+	 * interleaves with futex_unlock_pi() -- which does a similar lock
+	 * handoff -- such that the latter can observe the futex_q::pi_state
+	 * before __rt_mutex_start_proxy_lock() is done.
+	 */
+	raw_spin_lock_irq(&q.pi_state->pi_mutex.wait_lock);
+	spin_unlock(q.lock_ptr);
+	/*
+	 * __rt_mutex_start_proxy_lock() unconditionally enqueues the @rt_waiter
+	 * such that futex_unlock_pi() is guaranteed to observe the waiter when
+	 * it sees the futex_q::pi_state.
+	 */
+	ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current);
+	raw_spin_unlock_irq(&q.pi_state->pi_mutex.wait_lock);
+
+	if (ret) {
+		if (ret == 1)
+			ret = 0;
+		goto cleanup;
+	}
+
+	if (unlikely(to))
+		hrtimer_sleeper_start_expires(to, HRTIMER_MODE_ABS);
+
+	ret = rt_mutex_wait_proxy_lock(&q.pi_state->pi_mutex, to, &rt_waiter);
+
+cleanup:
+	spin_lock(q.lock_ptr);
+	/*
+	 * If we failed to acquire the lock (deadlock/signal/timeout), we must
+	 * first acquire the hb->lock before removing the lock from the
+	 * rt_mutex waitqueue, such that we can keep the hb and rt_mutex wait
+	 * lists consistent.
+	 *
+	 * In particular; it is important that futex_unlock_pi() can not
+	 * observe this inconsistency.
+	 */
+	if (ret && !rt_mutex_cleanup_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter))
+		ret = 0;
+
+no_block:
+	/*
+	 * Fixup the pi_state owner and possibly acquire the lock if we
+	 * haven't already.
+	 */
+	res = fixup_pi_owner(uaddr, &q, !ret);
+	/*
+	 * If fixup_pi_owner() returned an error, propagate that.  If it acquired
+	 * the lock, clear our -ETIMEDOUT or -EINTR.
+	 */
+	if (res)
+		ret = (res < 0) ? res : 0;
+
+	futex_unqueue_pi(&q);
+	spin_unlock(q.lock_ptr);
+	goto out;
+
+out_unlock_put_key:
+	futex_q_unlock(hb);
+
+out:
+	if (to) {
+		hrtimer_cancel(&to->timer);
+		destroy_hrtimer_on_stack(&to->timer);
+	}
+	return ret != -EINTR ? ret : -ERESTARTNOINTR;
+
+uaddr_faulted:
+	futex_q_unlock(hb);
+
+	ret = fault_in_user_writeable(uaddr);
+	if (ret)
+		goto out;
+
+	if (!(flags & FLAGS_SHARED))
+		goto retry_private;
+
+	goto retry;
+}
+
+/*
+ * Userspace attempted a TID -> 0 atomic transition, and failed.
+ * This is the in-kernel slowpath: we look up the PI state (if any),
+ * and do the rt-mutex unlock.
+ */
+int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
+{
+	u32 curval, uval, vpid = task_pid_vnr(current);
+	union futex_key key = FUTEX_KEY_INIT;
+	struct futex_hash_bucket *hb;
+	struct futex_q *top_waiter;
+	int ret;
+
+	if (!IS_ENABLED(CONFIG_FUTEX_PI))
+		return -ENOSYS;
+
+retry:
+	if (get_user(uval, uaddr))
+		return -EFAULT;
+	/*
+	 * We release only a lock we actually own:
+	 */
+	if ((uval & FUTEX_TID_MASK) != vpid)
+		return -EPERM;
+
+	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, FUTEX_WRITE);
+	if (ret)
+		return ret;
+
+	hb = futex_hash(&key);
+	spin_lock(&hb->lock);
+
+	/*
+	 * Check waiters first. We do not trust user space values at
+	 * all and we at least want to know if user space fiddled
+	 * with the futex value instead of blindly unlocking.
+	 */
+	top_waiter = futex_top_waiter(hb, &key);
+	if (top_waiter) {
+		struct futex_pi_state *pi_state = top_waiter->pi_state;
+
+		ret = -EINVAL;
+		if (!pi_state)
+			goto out_unlock;
+
+		/*
+		 * If current does not own the pi_state then the futex is
+		 * inconsistent and user space fiddled with the futex value.
+		 */
+		if (pi_state->owner != current)
+			goto out_unlock;
+
+		get_pi_state(pi_state);
+		/*
+		 * By taking wait_lock while still holding hb->lock, we ensure
+		 * there is no point where we hold neither; and therefore
+		 * wake_futex_p() must observe a state consistent with what we
+		 * observed.
+		 *
+		 * In particular; this forces __rt_mutex_start_proxy() to
+		 * complete such that we're guaranteed to observe the
+		 * rt_waiter. Also see the WARN in wake_futex_pi().
+		 */
+		raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+		spin_unlock(&hb->lock);
+
+		/* drops pi_state->pi_mutex.wait_lock */
+		ret = wake_futex_pi(uaddr, uval, pi_state);
+
+		put_pi_state(pi_state);
+
+		/*
+		 * Success, we're done! No tricky corner cases.
+		 */
+		if (!ret)
+			return ret;
+		/*
+		 * The atomic access to the futex value generated a
+		 * pagefault, so retry the user-access and the wakeup:
+		 */
+		if (ret == -EFAULT)
+			goto pi_faulted;
+		/*
+		 * A unconditional UNLOCK_PI op raced against a waiter
+		 * setting the FUTEX_WAITERS bit. Try again.
+		 */
+		if (ret == -EAGAIN)
+			goto pi_retry;
+		/*
+		 * wake_futex_pi has detected invalid state. Tell user
+		 * space.
+		 */
+		return ret;
+	}
+
+	/*
+	 * We have no kernel internal state, i.e. no waiters in the
+	 * kernel. Waiters which are about to queue themselves are stuck
+	 * on hb->lock. So we can safely ignore them. We do neither
+	 * preserve the WAITERS bit not the OWNER_DIED one. We are the
+	 * owner.
+	 */
+	if ((ret = futex_cmpxchg_value_locked(&curval, uaddr, uval, 0))) {
+		spin_unlock(&hb->lock);
+		switch (ret) {
+		case -EFAULT:
+			goto pi_faulted;
+
+		case -EAGAIN:
+			goto pi_retry;
+
+		default:
+			WARN_ON_ONCE(1);
+			return ret;
+		}
+	}
+
+	/*
+	 * If uval has changed, let user space handle it.
+	 */
+	ret = (curval == uval) ? 0 : -EAGAIN;
+
+out_unlock:
+	spin_unlock(&hb->lock);
+	return ret;
+
+pi_retry:
+	cond_resched();
+	goto retry;
+
+pi_faulted:
+
+	ret = fault_in_user_writeable(uaddr);
+	if (!ret)
+		goto retry;
+
+	return ret;
+}
+
diff --git a/kernel/futex/requeue.c b/kernel/futex/requeue.c
new file mode 100644
index 000000000..cba8b1a6a
--- /dev/null
+++ b/kernel/futex/requeue.c
@@ -0,0 +1,897 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/sched/signal.h>
+
+#include "futex.h"
+#include "../locking/rtmutex_common.h"
+
+/*
+ * On PREEMPT_RT, the hash bucket lock is a 'sleeping' spinlock with an
+ * underlying rtmutex. The task which is about to be requeued could have
+ * just woken up (timeout, signal). After the wake up the task has to
+ * acquire hash bucket lock, which is held by the requeue code.  As a task
+ * can only be blocked on _ONE_ rtmutex at a time, the proxy lock blocking
+ * and the hash bucket lock blocking would collide and corrupt state.
+ *
+ * On !PREEMPT_RT this is not a problem and everything could be serialized
+ * on hash bucket lock, but aside of having the benefit of common code,
+ * this allows to avoid doing the requeue when the task is already on the
+ * way out and taking the hash bucket lock of the original uaddr1 when the
+ * requeue has been completed.
+ *
+ * The following state transitions are valid:
+ *
+ * On the waiter side:
+ *   Q_REQUEUE_PI_NONE		-> Q_REQUEUE_PI_IGNORE
+ *   Q_REQUEUE_PI_IN_PROGRESS	-> Q_REQUEUE_PI_WAIT
+ *
+ * On the requeue side:
+ *   Q_REQUEUE_PI_NONE		-> Q_REQUEUE_PI_INPROGRESS
+ *   Q_REQUEUE_PI_IN_PROGRESS	-> Q_REQUEUE_PI_DONE/LOCKED
+ *   Q_REQUEUE_PI_IN_PROGRESS	-> Q_REQUEUE_PI_NONE (requeue failed)
+ *   Q_REQUEUE_PI_WAIT		-> Q_REQUEUE_PI_DONE/LOCKED
+ *   Q_REQUEUE_PI_WAIT		-> Q_REQUEUE_PI_IGNORE (requeue failed)
+ *
+ * The requeue side ignores a waiter with state Q_REQUEUE_PI_IGNORE as this
+ * signals that the waiter is already on the way out. It also means that
+ * the waiter is still on the 'wait' futex, i.e. uaddr1.
+ *
+ * The waiter side signals early wakeup to the requeue side either through
+ * setting state to Q_REQUEUE_PI_IGNORE or to Q_REQUEUE_PI_WAIT depending
+ * on the current state. In case of Q_REQUEUE_PI_IGNORE it can immediately
+ * proceed to take the hash bucket lock of uaddr1. If it set state to WAIT,
+ * which means the wakeup is interleaving with a requeue in progress it has
+ * to wait for the requeue side to change the state. Either to DONE/LOCKED
+ * or to IGNORE. DONE/LOCKED means the waiter q is now on the uaddr2 futex
+ * and either blocked (DONE) or has acquired it (LOCKED). IGNORE is set by
+ * the requeue side when the requeue attempt failed via deadlock detection
+ * and therefore the waiter q is still on the uaddr1 futex.
+ */
+enum {
+	Q_REQUEUE_PI_NONE		=  0,
+	Q_REQUEUE_PI_IGNORE,
+	Q_REQUEUE_PI_IN_PROGRESS,
+	Q_REQUEUE_PI_WAIT,
+	Q_REQUEUE_PI_DONE,
+	Q_REQUEUE_PI_LOCKED,
+};
+
+const struct futex_q futex_q_init = {
+	/* list gets initialized in futex_queue()*/
+	.key		= FUTEX_KEY_INIT,
+	.bitset		= FUTEX_BITSET_MATCH_ANY,
+	.requeue_state	= ATOMIC_INIT(Q_REQUEUE_PI_NONE),
+};
+
+/**
+ * requeue_futex() - Requeue a futex_q from one hb to another
+ * @q:		the futex_q to requeue
+ * @hb1:	the source hash_bucket
+ * @hb2:	the target hash_bucket
+ * @key2:	the new key for the requeued futex_q
+ */
+static inline
+void requeue_futex(struct futex_q *q, struct futex_hash_bucket *hb1,
+		   struct futex_hash_bucket *hb2, union futex_key *key2)
+{
+
+	/*
+	 * If key1 and key2 hash to the same bucket, no need to
+	 * requeue.
+	 */
+	if (likely(&hb1->chain != &hb2->chain)) {
+		plist_del(&q->list, &hb1->chain);
+		futex_hb_waiters_dec(hb1);
+		futex_hb_waiters_inc(hb2);
+		plist_add(&q->list, &hb2->chain);
+		q->lock_ptr = &hb2->lock;
+	}
+	q->key = *key2;
+}
+
+static inline bool futex_requeue_pi_prepare(struct futex_q *q,
+					    struct futex_pi_state *pi_state)
+{
+	int old, new;
+
+	/*
+	 * Set state to Q_REQUEUE_PI_IN_PROGRESS unless an early wakeup has
+	 * already set Q_REQUEUE_PI_IGNORE to signal that requeue should
+	 * ignore the waiter.
+	 */
+	old = atomic_read_acquire(&q->requeue_state);
+	do {
+		if (old == Q_REQUEUE_PI_IGNORE)
+			return false;
+
+		/*
+		 * futex_proxy_trylock_atomic() might have set it to
+		 * IN_PROGRESS and a interleaved early wake to WAIT.
+		 *
+		 * It was considered to have an extra state for that
+		 * trylock, but that would just add more conditionals
+		 * all over the place for a dubious value.
+		 */
+		if (old != Q_REQUEUE_PI_NONE)
+			break;
+
+		new = Q_REQUEUE_PI_IN_PROGRESS;
+	} while (!atomic_try_cmpxchg(&q->requeue_state, &old, new));
+
+	q->pi_state = pi_state;
+	return true;
+}
+
+static inline void futex_requeue_pi_complete(struct futex_q *q, int locked)
+{
+	int old, new;
+
+	old = atomic_read_acquire(&q->requeue_state);
+	do {
+		if (old == Q_REQUEUE_PI_IGNORE)
+			return;
+
+		if (locked >= 0) {
+			/* Requeue succeeded. Set DONE or LOCKED */
+			WARN_ON_ONCE(old != Q_REQUEUE_PI_IN_PROGRESS &&
+				     old != Q_REQUEUE_PI_WAIT);
+			new = Q_REQUEUE_PI_DONE + locked;
+		} else if (old == Q_REQUEUE_PI_IN_PROGRESS) {
+			/* Deadlock, no early wakeup interleave */
+			new = Q_REQUEUE_PI_NONE;
+		} else {
+			/* Deadlock, early wakeup interleave. */
+			WARN_ON_ONCE(old != Q_REQUEUE_PI_WAIT);
+			new = Q_REQUEUE_PI_IGNORE;
+		}
+	} while (!atomic_try_cmpxchg(&q->requeue_state, &old, new));
+
+#ifdef CONFIG_PREEMPT_RT
+	/* If the waiter interleaved with the requeue let it know */
+	if (unlikely(old == Q_REQUEUE_PI_WAIT))
+		rcuwait_wake_up(&q->requeue_wait);
+#endif
+}
+
+static inline int futex_requeue_pi_wakeup_sync(struct futex_q *q)
+{
+	int old, new;
+
+	old = atomic_read_acquire(&q->requeue_state);
+	do {
+		/* Is requeue done already? */
+		if (old >= Q_REQUEUE_PI_DONE)
+			return old;
+
+		/*
+		 * If not done, then tell the requeue code to either ignore
+		 * the waiter or to wake it up once the requeue is done.
+		 */
+		new = Q_REQUEUE_PI_WAIT;
+		if (old == Q_REQUEUE_PI_NONE)
+			new = Q_REQUEUE_PI_IGNORE;
+	} while (!atomic_try_cmpxchg(&q->requeue_state, &old, new));
+
+	/* If the requeue was in progress, wait for it to complete */
+	if (old == Q_REQUEUE_PI_IN_PROGRESS) {
+#ifdef CONFIG_PREEMPT_RT
+		rcuwait_wait_event(&q->requeue_wait,
+				   atomic_read(&q->requeue_state) != Q_REQUEUE_PI_WAIT,
+				   TASK_UNINTERRUPTIBLE);
+#else
+		(void)atomic_cond_read_relaxed(&q->requeue_state, VAL != Q_REQUEUE_PI_WAIT);
+#endif
+	}
+
+	/*
+	 * Requeue is now either prohibited or complete. Reread state
+	 * because during the wait above it might have changed. Nothing
+	 * will modify q->requeue_state after this point.
+	 */
+	return atomic_read(&q->requeue_state);
+}
+
+/**
+ * requeue_pi_wake_futex() - Wake a task that acquired the lock during requeue
+ * @q:		the futex_q
+ * @key:	the key of the requeue target futex
+ * @hb:		the hash_bucket of the requeue target futex
+ *
+ * During futex_requeue, with requeue_pi=1, it is possible to acquire the
+ * target futex if it is uncontended or via a lock steal.
+ *
+ * 1) Set @q::key to the requeue target futex key so the waiter can detect
+ *    the wakeup on the right futex.
+ *
+ * 2) Dequeue @q from the hash bucket.
+ *
+ * 3) Set @q::rt_waiter to NULL so the woken up task can detect atomic lock
+ *    acquisition.
+ *
+ * 4) Set the q->lock_ptr to the requeue target hb->lock for the case that
+ *    the waiter has to fixup the pi state.
+ *
+ * 5) Complete the requeue state so the waiter can make progress. After
+ *    this point the waiter task can return from the syscall immediately in
+ *    case that the pi state does not have to be fixed up.
+ *
+ * 6) Wake the waiter task.
+ *
+ * Must be called with both q->lock_ptr and hb->lock held.
+ */
+static inline
+void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key,
+			   struct futex_hash_bucket *hb)
+{
+	q->key = *key;
+
+	__futex_unqueue(q);
+
+	WARN_ON(!q->rt_waiter);
+	q->rt_waiter = NULL;
+
+	q->lock_ptr = &hb->lock;
+
+	/* Signal locked state to the waiter */
+	futex_requeue_pi_complete(q, 1);
+	wake_up_state(q->task, TASK_NORMAL);
+}
+
+/**
+ * futex_proxy_trylock_atomic() - Attempt an atomic lock for the top waiter
+ * @pifutex:		the user address of the to futex
+ * @hb1:		the from futex hash bucket, must be locked by the caller
+ * @hb2:		the to futex hash bucket, must be locked by the caller
+ * @key1:		the from futex key
+ * @key2:		the to futex key
+ * @ps:			address to store the pi_state pointer
+ * @exiting:		Pointer to store the task pointer of the owner task
+ *			which is in the middle of exiting
+ * @set_waiters:	force setting the FUTEX_WAITERS bit (1) or not (0)
+ *
+ * Try and get the lock on behalf of the top waiter if we can do it atomically.
+ * Wake the top waiter if we succeed.  If the caller specified set_waiters,
+ * then direct futex_lock_pi_atomic() to force setting the FUTEX_WAITERS bit.
+ * hb1 and hb2 must be held by the caller.
+ *
+ * @exiting is only set when the return value is -EBUSY. If so, this holds
+ * a refcount on the exiting task on return and the caller needs to drop it
+ * after waiting for the exit to complete.
+ *
+ * Return:
+ *  -  0 - failed to acquire the lock atomically;
+ *  - >0 - acquired the lock, return value is vpid of the top_waiter
+ *  - <0 - error
+ */
+static int
+futex_proxy_trylock_atomic(u32 __user *pifutex, struct futex_hash_bucket *hb1,
+			   struct futex_hash_bucket *hb2, union futex_key *key1,
+			   union futex_key *key2, struct futex_pi_state **ps,
+			   struct task_struct **exiting, int set_waiters)
+{
+	struct futex_q *top_waiter = NULL;
+	u32 curval;
+	int ret;
+
+	if (futex_get_value_locked(&curval, pifutex))
+		return -EFAULT;
+
+	if (unlikely(should_fail_futex(true)))
+		return -EFAULT;
+
+	/*
+	 * Find the top_waiter and determine if there are additional waiters.
+	 * If the caller intends to requeue more than 1 waiter to pifutex,
+	 * force futex_lock_pi_atomic() to set the FUTEX_WAITERS bit now,
+	 * as we have means to handle the possible fault.  If not, don't set
+	 * the bit unnecessarily as it will force the subsequent unlock to enter
+	 * the kernel.
+	 */
+	top_waiter = futex_top_waiter(hb1, key1);
+
+	/* There are no waiters, nothing for us to do. */
+	if (!top_waiter)
+		return 0;
+
+	/*
+	 * Ensure that this is a waiter sitting in futex_wait_requeue_pi()
+	 * and waiting on the 'waitqueue' futex which is always !PI.
+	 */
+	if (!top_waiter->rt_waiter || top_waiter->pi_state)
+		return -EINVAL;
+
+	/* Ensure we requeue to the expected futex. */
+	if (!futex_match(top_waiter->requeue_pi_key, key2))
+		return -EINVAL;
+
+	/* Ensure that this does not race against an early wakeup */
+	if (!futex_requeue_pi_prepare(top_waiter, NULL))
+		return -EAGAIN;
+
+	/*
+	 * Try to take the lock for top_waiter and set the FUTEX_WAITERS bit
+	 * in the contended case or if @set_waiters is true.
+	 *
+	 * In the contended case PI state is attached to the lock owner. If
+	 * the user space lock can be acquired then PI state is attached to
+	 * the new owner (@top_waiter->task) when @set_waiters is true.
+	 */
+	ret = futex_lock_pi_atomic(pifutex, hb2, key2, ps, top_waiter->task,
+				   exiting, set_waiters);
+	if (ret == 1) {
+		/*
+		 * Lock was acquired in user space and PI state was
+		 * attached to @top_waiter->task. That means state is fully
+		 * consistent and the waiter can return to user space
+		 * immediately after the wakeup.
+		 */
+		requeue_pi_wake_futex(top_waiter, key2, hb2);
+	} else if (ret < 0) {
+		/* Rewind top_waiter::requeue_state */
+		futex_requeue_pi_complete(top_waiter, ret);
+	} else {
+		/*
+		 * futex_lock_pi_atomic() did not acquire the user space
+		 * futex, but managed to establish the proxy lock and pi
+		 * state. top_waiter::requeue_state cannot be fixed up here
+		 * because the waiter is not enqueued on the rtmutex
+		 * yet. This is handled at the callsite depending on the
+		 * result of rt_mutex_start_proxy_lock() which is
+		 * guaranteed to be reached with this function returning 0.
+		 */
+	}
+	return ret;
+}
+
+/**
+ * futex_requeue() - Requeue waiters from uaddr1 to uaddr2
+ * @uaddr1:	source futex user address
+ * @flags:	futex flags (FLAGS_SHARED, etc.)
+ * @uaddr2:	target futex user address
+ * @nr_wake:	number of waiters to wake (must be 1 for requeue_pi)
+ * @nr_requeue:	number of waiters to requeue (0-INT_MAX)
+ * @cmpval:	@uaddr1 expected value (or %NULL)
+ * @requeue_pi:	if we are attempting to requeue from a non-pi futex to a
+ *		pi futex (pi to pi requeue is not supported)
+ *
+ * Requeue waiters on uaddr1 to uaddr2. In the requeue_pi case, try to acquire
+ * uaddr2 atomically on behalf of the top waiter.
+ *
+ * Return:
+ *  - >=0 - on success, the number of tasks requeued or woken;
+ *  -  <0 - on error
+ */
+int futex_requeue(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
+		  int nr_wake, int nr_requeue, u32 *cmpval, int requeue_pi)
+{
+	union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT;
+	int task_count = 0, ret;
+	struct futex_pi_state *pi_state = NULL;
+	struct futex_hash_bucket *hb1, *hb2;
+	struct futex_q *this, *next;
+	DEFINE_WAKE_Q(wake_q);
+
+	if (nr_wake < 0 || nr_requeue < 0)
+		return -EINVAL;
+
+	/*
+	 * When PI not supported: return -ENOSYS if requeue_pi is true,
+	 * consequently the compiler knows requeue_pi is always false past
+	 * this point which will optimize away all the conditional code
+	 * further down.
+	 */
+	if (!IS_ENABLED(CONFIG_FUTEX_PI) && requeue_pi)
+		return -ENOSYS;
+
+	if (requeue_pi) {
+		/*
+		 * Requeue PI only works on two distinct uaddrs. This
+		 * check is only valid for private futexes. See below.
+		 */
+		if (uaddr1 == uaddr2)
+			return -EINVAL;
+
+		/*
+		 * futex_requeue() allows the caller to define the number
+		 * of waiters to wake up via the @nr_wake argument. With
+		 * REQUEUE_PI, waking up more than one waiter is creating
+		 * more problems than it solves. Waking up a waiter makes
+		 * only sense if the PI futex @uaddr2 is uncontended as
+		 * this allows the requeue code to acquire the futex
+		 * @uaddr2 before waking the waiter. The waiter can then
+		 * return to user space without further action. A secondary
+		 * wakeup would just make the futex_wait_requeue_pi()
+		 * handling more complex, because that code would have to
+		 * look up pi_state and do more or less all the handling
+		 * which the requeue code has to do for the to be requeued
+		 * waiters. So restrict the number of waiters to wake to
+		 * one, and only wake it up when the PI futex is
+		 * uncontended. Otherwise requeue it and let the unlock of
+		 * the PI futex handle the wakeup.
+		 *
+		 * All REQUEUE_PI users, e.g. pthread_cond_signal() and
+		 * pthread_cond_broadcast() must use nr_wake=1.
+		 */
+		if (nr_wake != 1)
+			return -EINVAL;
+
+		/*
+		 * requeue_pi requires a pi_state, try to allocate it now
+		 * without any locks in case it fails.
+		 */
+		if (refill_pi_state_cache())
+			return -ENOMEM;
+	}
+
+retry:
+	ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, FUTEX_READ);
+	if (unlikely(ret != 0))
+		return ret;
+	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2,
+			    requeue_pi ? FUTEX_WRITE : FUTEX_READ);
+	if (unlikely(ret != 0))
+		return ret;
+
+	/*
+	 * The check above which compares uaddrs is not sufficient for
+	 * shared futexes. We need to compare the keys:
+	 */
+	if (requeue_pi && futex_match(&key1, &key2))
+		return -EINVAL;
+
+	hb1 = futex_hash(&key1);
+	hb2 = futex_hash(&key2);
+
+retry_private:
+	futex_hb_waiters_inc(hb2);
+	double_lock_hb(hb1, hb2);
+
+	if (likely(cmpval != NULL)) {
+		u32 curval;
+
+		ret = futex_get_value_locked(&curval, uaddr1);
+
+		if (unlikely(ret)) {
+			double_unlock_hb(hb1, hb2);
+			futex_hb_waiters_dec(hb2);
+
+			ret = get_user(curval, uaddr1);
+			if (ret)
+				return ret;
+
+			if (!(flags & FLAGS_SHARED))
+				goto retry_private;
+
+			goto retry;
+		}
+		if (curval != *cmpval) {
+			ret = -EAGAIN;
+			goto out_unlock;
+		}
+	}
+
+	if (requeue_pi) {
+		struct task_struct *exiting = NULL;
+
+		/*
+		 * Attempt to acquire uaddr2 and wake the top waiter. If we
+		 * intend to requeue waiters, force setting the FUTEX_WAITERS
+		 * bit.  We force this here where we are able to easily handle
+		 * faults rather in the requeue loop below.
+		 *
+		 * Updates topwaiter::requeue_state if a top waiter exists.
+		 */
+		ret = futex_proxy_trylock_atomic(uaddr2, hb1, hb2, &key1,
+						 &key2, &pi_state,
+						 &exiting, nr_requeue);
+
+		/*
+		 * At this point the top_waiter has either taken uaddr2 or
+		 * is waiting on it. In both cases pi_state has been
+		 * established and an initial refcount on it. In case of an
+		 * error there's nothing.
+		 *
+		 * The top waiter's requeue_state is up to date:
+		 *
+		 *  - If the lock was acquired atomically (ret == 1), then
+		 *    the state is Q_REQUEUE_PI_LOCKED.
+		 *
+		 *    The top waiter has been dequeued and woken up and can
+		 *    return to user space immediately. The kernel/user
+		 *    space state is consistent. In case that there must be
+		 *    more waiters requeued the WAITERS bit in the user
+		 *    space futex is set so the top waiter task has to go
+		 *    into the syscall slowpath to unlock the futex. This
+		 *    will block until this requeue operation has been
+		 *    completed and the hash bucket locks have been
+		 *    dropped.
+		 *
+		 *  - If the trylock failed with an error (ret < 0) then
+		 *    the state is either Q_REQUEUE_PI_NONE, i.e. "nothing
+		 *    happened", or Q_REQUEUE_PI_IGNORE when there was an
+		 *    interleaved early wakeup.
+		 *
+		 *  - If the trylock did not succeed (ret == 0) then the
+		 *    state is either Q_REQUEUE_PI_IN_PROGRESS or
+		 *    Q_REQUEUE_PI_WAIT if an early wakeup interleaved.
+		 *    This will be cleaned up in the loop below, which
+		 *    cannot fail because futex_proxy_trylock_atomic() did
+		 *    the same sanity checks for requeue_pi as the loop
+		 *    below does.
+		 */
+		switch (ret) {
+		case 0:
+			/* We hold a reference on the pi state. */
+			break;
+
+		case 1:
+			/*
+			 * futex_proxy_trylock_atomic() acquired the user space
+			 * futex. Adjust task_count.
+			 */
+			task_count++;
+			ret = 0;
+			break;
+
+		/*
+		 * If the above failed, then pi_state is NULL and
+		 * waiter::requeue_state is correct.
+		 */
+		case -EFAULT:
+			double_unlock_hb(hb1, hb2);
+			futex_hb_waiters_dec(hb2);
+			ret = fault_in_user_writeable(uaddr2);
+			if (!ret)
+				goto retry;
+			return ret;
+		case -EBUSY:
+		case -EAGAIN:
+			/*
+			 * Two reasons for this:
+			 * - EBUSY: Owner is exiting and we just wait for the
+			 *   exit to complete.
+			 * - EAGAIN: The user space value changed.
+			 */
+			double_unlock_hb(hb1, hb2);
+			futex_hb_waiters_dec(hb2);
+			/*
+			 * Handle the case where the owner is in the middle of
+			 * exiting. Wait for the exit to complete otherwise
+			 * this task might loop forever, aka. live lock.
+			 */
+			wait_for_owner_exiting(ret, exiting);
+			cond_resched();
+			goto retry;
+		default:
+			goto out_unlock;
+		}
+	}
+
+	plist_for_each_entry_safe(this, next, &hb1->chain, list) {
+		if (task_count - nr_wake >= nr_requeue)
+			break;
+
+		if (!futex_match(&this->key, &key1))
+			continue;
+
+		/*
+		 * FUTEX_WAIT_REQUEUE_PI and FUTEX_CMP_REQUEUE_PI should always
+		 * be paired with each other and no other futex ops.
+		 *
+		 * We should never be requeueing a futex_q with a pi_state,
+		 * which is awaiting a futex_unlock_pi().
+		 */
+		if ((requeue_pi && !this->rt_waiter) ||
+		    (!requeue_pi && this->rt_waiter) ||
+		    this->pi_state) {
+			ret = -EINVAL;
+			break;
+		}
+
+		/* Plain futexes just wake or requeue and are done */
+		if (!requeue_pi) {
+			if (++task_count <= nr_wake)
+				futex_wake_mark(&wake_q, this);
+			else
+				requeue_futex(this, hb1, hb2, &key2);
+			continue;
+		}
+
+		/* Ensure we requeue to the expected futex for requeue_pi. */
+		if (!futex_match(this->requeue_pi_key, &key2)) {
+			ret = -EINVAL;
+			break;
+		}
+
+		/*
+		 * Requeue nr_requeue waiters and possibly one more in the case
+		 * of requeue_pi if we couldn't acquire the lock atomically.
+		 *
+		 * Prepare the waiter to take the rt_mutex. Take a refcount
+		 * on the pi_state and store the pointer in the futex_q
+		 * object of the waiter.
+		 */
+		get_pi_state(pi_state);
+
+		/* Don't requeue when the waiter is already on the way out. */
+		if (!futex_requeue_pi_prepare(this, pi_state)) {
+			/*
+			 * Early woken waiter signaled that it is on the
+			 * way out. Drop the pi_state reference and try the
+			 * next waiter. @this->pi_state is still NULL.
+			 */
+			put_pi_state(pi_state);
+			continue;
+		}
+
+		ret = rt_mutex_start_proxy_lock(&pi_state->pi_mutex,
+						this->rt_waiter,
+						this->task);
+
+		if (ret == 1) {
+			/*
+			 * We got the lock. We do neither drop the refcount
+			 * on pi_state nor clear this->pi_state because the
+			 * waiter needs the pi_state for cleaning up the
+			 * user space value. It will drop the refcount
+			 * after doing so. this::requeue_state is updated
+			 * in the wakeup as well.
+			 */
+			requeue_pi_wake_futex(this, &key2, hb2);
+			task_count++;
+		} else if (!ret) {
+			/* Waiter is queued, move it to hb2 */
+			requeue_futex(this, hb1, hb2, &key2);
+			futex_requeue_pi_complete(this, 0);
+			task_count++;
+		} else {
+			/*
+			 * rt_mutex_start_proxy_lock() detected a potential
+			 * deadlock when we tried to queue that waiter.
+			 * Drop the pi_state reference which we took above
+			 * and remove the pointer to the state from the
+			 * waiters futex_q object.
+			 */
+			this->pi_state = NULL;
+			put_pi_state(pi_state);
+			futex_requeue_pi_complete(this, ret);
+			/*
+			 * We stop queueing more waiters and let user space
+			 * deal with the mess.
+			 */
+			break;
+		}
+	}
+
+	/*
+	 * We took an extra initial reference to the pi_state in
+	 * futex_proxy_trylock_atomic(). We need to drop it here again.
+	 */
+	put_pi_state(pi_state);
+
+out_unlock:
+	double_unlock_hb(hb1, hb2);
+	wake_up_q(&wake_q);
+	futex_hb_waiters_dec(hb2);
+	return ret ? ret : task_count;
+}
+
+/**
+ * handle_early_requeue_pi_wakeup() - Handle early wakeup on the initial futex
+ * @hb:		the hash_bucket futex_q was original enqueued on
+ * @q:		the futex_q woken while waiting to be requeued
+ * @timeout:	the timeout associated with the wait (NULL if none)
+ *
+ * Determine the cause for the early wakeup.
+ *
+ * Return:
+ *  -EWOULDBLOCK or -ETIMEDOUT or -ERESTARTNOINTR
+ */
+static inline
+int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb,
+				   struct futex_q *q,
+				   struct hrtimer_sleeper *timeout)
+{
+	int ret;
+
+	/*
+	 * With the hb lock held, we avoid races while we process the wakeup.
+	 * We only need to hold hb (and not hb2) to ensure atomicity as the
+	 * wakeup code can't change q.key from uaddr to uaddr2 if we hold hb.
+	 * It can't be requeued from uaddr2 to something else since we don't
+	 * support a PI aware source futex for requeue.
+	 */
+	WARN_ON_ONCE(&hb->lock != q->lock_ptr);
+
+	/*
+	 * We were woken prior to requeue by a timeout or a signal.
+	 * Unqueue the futex_q and determine which it was.
+	 */
+	plist_del(&q->list, &hb->chain);
+	futex_hb_waiters_dec(hb);
+
+	/* Handle spurious wakeups gracefully */
+	ret = -EWOULDBLOCK;
+	if (timeout && !timeout->task)
+		ret = -ETIMEDOUT;
+	else if (signal_pending(current))
+		ret = -ERESTARTNOINTR;
+	return ret;
+}
+
+/**
+ * futex_wait_requeue_pi() - Wait on uaddr and take uaddr2
+ * @uaddr:	the futex we initially wait on (non-pi)
+ * @flags:	futex flags (FLAGS_SHARED, FLAGS_CLOCKRT, etc.), they must be
+ *		the same type, no requeueing from private to shared, etc.
+ * @val:	the expected value of uaddr
+ * @abs_time:	absolute timeout
+ * @bitset:	32 bit wakeup bitset set by userspace, defaults to all
+ * @uaddr2:	the pi futex we will take prior to returning to user-space
+ *
+ * The caller will wait on uaddr and will be requeued by futex_requeue() to
+ * uaddr2 which must be PI aware and unique from uaddr.  Normal wakeup will wake
+ * on uaddr2 and complete the acquisition of the rt_mutex prior to returning to
+ * userspace.  This ensures the rt_mutex maintains an owner when it has waiters;
+ * without one, the pi logic would not know which task to boost/deboost, if
+ * there was a need to.
+ *
+ * We call schedule in futex_wait_queue() when we enqueue and return there
+ * via the following--
+ * 1) wakeup on uaddr2 after an atomic lock acquisition by futex_requeue()
+ * 2) wakeup on uaddr2 after a requeue
+ * 3) signal
+ * 4) timeout
+ *
+ * If 3, cleanup and return -ERESTARTNOINTR.
+ *
+ * If 2, we may then block on trying to take the rt_mutex and return via:
+ * 5) successful lock
+ * 6) signal
+ * 7) timeout
+ * 8) other lock acquisition failure
+ *
+ * If 6, return -EWOULDBLOCK (restarting the syscall would do the same).
+ *
+ * If 4 or 7, we cleanup and return with -ETIMEDOUT.
+ *
+ * Return:
+ *  -  0 - On success;
+ *  - <0 - On error
+ */
+int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
+			  u32 val, ktime_t *abs_time, u32 bitset,
+			  u32 __user *uaddr2)
+{
+	struct hrtimer_sleeper timeout, *to;
+	struct rt_mutex_waiter rt_waiter;
+	struct futex_hash_bucket *hb;
+	union futex_key key2 = FUTEX_KEY_INIT;
+	struct futex_q q = futex_q_init;
+	struct rt_mutex_base *pi_mutex;
+	int res, ret;
+
+	if (!IS_ENABLED(CONFIG_FUTEX_PI))
+		return -ENOSYS;
+
+	if (uaddr == uaddr2)
+		return -EINVAL;
+
+	if (!bitset)
+		return -EINVAL;
+
+	to = futex_setup_timer(abs_time, &timeout, flags,
+			       current->timer_slack_ns);
+
+	/*
+	 * The waiter is allocated on our stack, manipulated by the requeue
+	 * code while we sleep on uaddr.
+	 */
+	rt_mutex_init_waiter(&rt_waiter);
+
+	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, FUTEX_WRITE);
+	if (unlikely(ret != 0))
+		goto out;
+
+	q.bitset = bitset;
+	q.rt_waiter = &rt_waiter;
+	q.requeue_pi_key = &key2;
+
+	/*
+	 * Prepare to wait on uaddr. On success, it holds hb->lock and q
+	 * is initialized.
+	 */
+	ret = futex_wait_setup(uaddr, val, flags, &q, &hb);
+	if (ret)
+		goto out;
+
+	/*
+	 * The check above which compares uaddrs is not sufficient for
+	 * shared futexes. We need to compare the keys:
+	 */
+	if (futex_match(&q.key, &key2)) {
+		futex_q_unlock(hb);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Queue the futex_q, drop the hb lock, wait for wakeup. */
+	futex_wait_queue(hb, &q, to);
+
+	switch (futex_requeue_pi_wakeup_sync(&q)) {
+	case Q_REQUEUE_PI_IGNORE:
+		/* The waiter is still on uaddr1 */
+		spin_lock(&hb->lock);
+		ret = handle_early_requeue_pi_wakeup(hb, &q, to);
+		spin_unlock(&hb->lock);
+		break;
+
+	case Q_REQUEUE_PI_LOCKED:
+		/* The requeue acquired the lock */
+		if (q.pi_state && (q.pi_state->owner != current)) {
+			spin_lock(q.lock_ptr);
+			ret = fixup_pi_owner(uaddr2, &q, true);
+			/*
+			 * Drop the reference to the pi state which the
+			 * requeue_pi() code acquired for us.
+			 */
+			put_pi_state(q.pi_state);
+			spin_unlock(q.lock_ptr);
+			/*
+			 * Adjust the return value. It's either -EFAULT or
+			 * success (1) but the caller expects 0 for success.
+			 */
+			ret = ret < 0 ? ret : 0;
+		}
+		break;
+
+	case Q_REQUEUE_PI_DONE:
+		/* Requeue completed. Current is 'pi_blocked_on' the rtmutex */
+		pi_mutex = &q.pi_state->pi_mutex;
+		ret = rt_mutex_wait_proxy_lock(pi_mutex, to, &rt_waiter);
+
+		/* Current is not longer pi_blocked_on */
+		spin_lock(q.lock_ptr);
+		if (ret && !rt_mutex_cleanup_proxy_lock(pi_mutex, &rt_waiter))
+			ret = 0;
+
+		debug_rt_mutex_free_waiter(&rt_waiter);
+		/*
+		 * Fixup the pi_state owner and possibly acquire the lock if we
+		 * haven't already.
+		 */
+		res = fixup_pi_owner(uaddr2, &q, !ret);
+		/*
+		 * If fixup_pi_owner() returned an error, propagate that.  If it
+		 * acquired the lock, clear -ETIMEDOUT or -EINTR.
+		 */
+		if (res)
+			ret = (res < 0) ? res : 0;
+
+		futex_unqueue_pi(&q);
+		spin_unlock(q.lock_ptr);
+
+		if (ret == -EINTR) {
+			/*
+			 * We've already been requeued, but cannot restart
+			 * by calling futex_lock_pi() directly. We could
+			 * restart this syscall, but it would detect that
+			 * the user space "val" changed and return
+			 * -EWOULDBLOCK.  Save the overhead of the restart
+			 * and return -EWOULDBLOCK directly.
+			 */
+			ret = -EWOULDBLOCK;
+		}
+		break;
+	default:
+		BUG();
+	}
+
+out:
+	if (to) {
+		hrtimer_cancel(&to->timer);
+		destroy_hrtimer_on_stack(&to->timer);
+	}
+	return ret;
+}
+
diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c
new file mode 100644
index 000000000..a8074079b
--- /dev/null
+++ b/kernel/futex/syscalls.c
@@ -0,0 +1,379 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/compat.h>
+#include <linux/syscalls.h>
+#include <linux/time_namespace.h>
+
+#include "futex.h"
+
+/*
+ * Support for robust futexes: the kernel cleans up held futexes at
+ * thread exit time.
+ *
+ * Implementation: user-space maintains a per-thread list of locks it
+ * is holding. Upon do_exit(), the kernel carefully walks this list,
+ * and marks all locks that are owned by this thread with the
+ * FUTEX_OWNER_DIED bit, and wakes up a waiter (if any). The list is
+ * always manipulated with the lock held, so the list is private and
+ * per-thread. Userspace also maintains a per-thread 'list_op_pending'
+ * field, to allow the kernel to clean up if the thread dies after
+ * acquiring the lock, but just before it could have added itself to
+ * the list. There can only be one such pending lock.
+ */
+
+/**
+ * sys_set_robust_list() - Set the robust-futex list head of a task
+ * @head:	pointer to the list-head
+ * @len:	length of the list-head, as userspace expects
+ */
+SYSCALL_DEFINE2(set_robust_list, struct robust_list_head __user *, head,
+		size_t, len)
+{
+	/*
+	 * The kernel knows only one size for now:
+	 */
+	if (unlikely(len != sizeof(*head)))
+		return -EINVAL;
+
+	current->robust_list = head;
+
+	return 0;
+}
+
+/**
+ * sys_get_robust_list() - Get the robust-futex list head of a task
+ * @pid:	pid of the process [zero for current task]
+ * @head_ptr:	pointer to a list-head pointer, the kernel fills it in
+ * @len_ptr:	pointer to a length field, the kernel fills in the header size
+ */
+SYSCALL_DEFINE3(get_robust_list, int, pid,
+		struct robust_list_head __user * __user *, head_ptr,
+		size_t __user *, len_ptr)
+{
+	struct robust_list_head __user *head;
+	unsigned long ret;
+	struct task_struct *p;
+
+	rcu_read_lock();
+
+	ret = -ESRCH;
+	if (!pid)
+		p = current;
+	else {
+		p = find_task_by_vpid(pid);
+		if (!p)
+			goto err_unlock;
+	}
+
+	ret = -EPERM;
+	if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
+		goto err_unlock;
+
+	head = p->robust_list;
+	rcu_read_unlock();
+
+	if (put_user(sizeof(*head), len_ptr))
+		return -EFAULT;
+	return put_user(head, head_ptr);
+
+err_unlock:
+	rcu_read_unlock();
+
+	return ret;
+}
+
+long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
+		u32 __user *uaddr2, u32 val2, u32 val3)
+{
+	int cmd = op & FUTEX_CMD_MASK;
+	unsigned int flags = 0;
+
+	if (!(op & FUTEX_PRIVATE_FLAG))
+		flags |= FLAGS_SHARED;
+
+	if (op & FUTEX_CLOCK_REALTIME) {
+		flags |= FLAGS_CLOCKRT;
+		if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI &&
+		    cmd != FUTEX_LOCK_PI2)
+			return -ENOSYS;
+	}
+
+	switch (cmd) {
+	case FUTEX_WAIT:
+		val3 = FUTEX_BITSET_MATCH_ANY;
+		fallthrough;
+	case FUTEX_WAIT_BITSET:
+		return futex_wait(uaddr, flags, val, timeout, val3);
+	case FUTEX_WAKE:
+		val3 = FUTEX_BITSET_MATCH_ANY;
+		fallthrough;
+	case FUTEX_WAKE_BITSET:
+		return futex_wake(uaddr, flags, val, val3);
+	case FUTEX_REQUEUE:
+		return futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0);
+	case FUTEX_CMP_REQUEUE:
+		return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0);
+	case FUTEX_WAKE_OP:
+		return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
+	case FUTEX_LOCK_PI:
+		flags |= FLAGS_CLOCKRT;
+		fallthrough;
+	case FUTEX_LOCK_PI2:
+		return futex_lock_pi(uaddr, flags, timeout, 0);
+	case FUTEX_UNLOCK_PI:
+		return futex_unlock_pi(uaddr, flags);
+	case FUTEX_TRYLOCK_PI:
+		return futex_lock_pi(uaddr, flags, NULL, 1);
+	case FUTEX_WAIT_REQUEUE_PI:
+		val3 = FUTEX_BITSET_MATCH_ANY;
+		return futex_wait_requeue_pi(uaddr, flags, val, timeout, val3,
+					     uaddr2);
+	case FUTEX_CMP_REQUEUE_PI:
+		return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1);
+	}
+	return -ENOSYS;
+}
+
+static __always_inline bool futex_cmd_has_timeout(u32 cmd)
+{
+	switch (cmd) {
+	case FUTEX_WAIT:
+	case FUTEX_LOCK_PI:
+	case FUTEX_LOCK_PI2:
+	case FUTEX_WAIT_BITSET:
+	case FUTEX_WAIT_REQUEUE_PI:
+		return true;
+	}
+	return false;
+}
+
+static __always_inline int
+futex_init_timeout(u32 cmd, u32 op, struct timespec64 *ts, ktime_t *t)
+{
+	if (!timespec64_valid(ts))
+		return -EINVAL;
+
+	*t = timespec64_to_ktime(*ts);
+	if (cmd == FUTEX_WAIT)
+		*t = ktime_add_safe(ktime_get(), *t);
+	else if (cmd != FUTEX_LOCK_PI && !(op & FUTEX_CLOCK_REALTIME))
+		*t = timens_ktime_to_host(CLOCK_MONOTONIC, *t);
+	return 0;
+}
+
+SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
+		const struct __kernel_timespec __user *, utime,
+		u32 __user *, uaddr2, u32, val3)
+{
+	int ret, cmd = op & FUTEX_CMD_MASK;
+	ktime_t t, *tp = NULL;
+	struct timespec64 ts;
+
+	if (utime && futex_cmd_has_timeout(cmd)) {
+		if (unlikely(should_fail_futex(!(op & FUTEX_PRIVATE_FLAG))))
+			return -EFAULT;
+		if (get_timespec64(&ts, utime))
+			return -EFAULT;
+		ret = futex_init_timeout(cmd, op, &ts, &t);
+		if (ret)
+			return ret;
+		tp = &t;
+	}
+
+	return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
+}
+
+/* Mask of available flags for each futex in futex_waitv list */
+#define FUTEXV_WAITER_MASK (FUTEX_32 | FUTEX_PRIVATE_FLAG)
+
+/**
+ * futex_parse_waitv - Parse a waitv array from userspace
+ * @futexv:	Kernel side list of waiters to be filled
+ * @uwaitv:     Userspace list to be parsed
+ * @nr_futexes: Length of futexv
+ *
+ * Return: Error code on failure, 0 on success
+ */
+static int futex_parse_waitv(struct futex_vector *futexv,
+			     struct futex_waitv __user *uwaitv,
+			     unsigned int nr_futexes)
+{
+	struct futex_waitv aux;
+	unsigned int i;
+
+	for (i = 0; i < nr_futexes; i++) {
+		if (copy_from_user(&aux, &uwaitv[i], sizeof(aux)))
+			return -EFAULT;
+
+		if ((aux.flags & ~FUTEXV_WAITER_MASK) || aux.__reserved)
+			return -EINVAL;
+
+		if (!(aux.flags & FUTEX_32))
+			return -EINVAL;
+
+		futexv[i].w.flags = aux.flags;
+		futexv[i].w.val = aux.val;
+		futexv[i].w.uaddr = aux.uaddr;
+		futexv[i].q = futex_q_init;
+	}
+
+	return 0;
+}
+
+/**
+ * sys_futex_waitv - Wait on a list of futexes
+ * @waiters:    List of futexes to wait on
+ * @nr_futexes: Length of futexv
+ * @flags:      Flag for timeout (monotonic/realtime)
+ * @timeout:	Optional absolute timeout.
+ * @clockid:	Clock to be used for the timeout, realtime or monotonic.
+ *
+ * Given an array of `struct futex_waitv`, wait on each uaddr. The thread wakes
+ * if a futex_wake() is performed at any uaddr. The syscall returns immediately
+ * if any waiter has *uaddr != val. *timeout is an optional timeout value for
+ * the operation. Each waiter has individual flags. The `flags` argument for
+ * the syscall should be used solely for specifying the timeout as realtime, if
+ * needed. Flags for private futexes, sizes, etc. should be used on the
+ * individual flags of each waiter.
+ *
+ * Returns the array index of one of the woken futexes. No further information
+ * is provided: any number of other futexes may also have been woken by the
+ * same event, and if more than one futex was woken, the retrned index may
+ * refer to any one of them. (It is not necessaryily the futex with the
+ * smallest index, nor the one most recently woken, nor...)
+ */
+
+SYSCALL_DEFINE5(futex_waitv, struct futex_waitv __user *, waiters,
+		unsigned int, nr_futexes, unsigned int, flags,
+		struct __kernel_timespec __user *, timeout, clockid_t, clockid)
+{
+	struct hrtimer_sleeper to;
+	struct futex_vector *futexv;
+	struct timespec64 ts;
+	ktime_t time;
+	int ret;
+
+	/* This syscall supports no flags for now */
+	if (flags)
+		return -EINVAL;
+
+	if (!nr_futexes || nr_futexes > FUTEX_WAITV_MAX || !waiters)
+		return -EINVAL;
+
+	if (timeout) {
+		int flag_clkid = 0, flag_init = 0;
+
+		if (clockid == CLOCK_REALTIME) {
+			flag_clkid = FLAGS_CLOCKRT;
+			flag_init = FUTEX_CLOCK_REALTIME;
+		}
+
+		if (clockid != CLOCK_REALTIME && clockid != CLOCK_MONOTONIC)
+			return -EINVAL;
+
+		if (get_timespec64(&ts, timeout))
+			return -EFAULT;
+
+		/*
+		 * Since there's no opcode for futex_waitv, use
+		 * FUTEX_WAIT_BITSET that uses absolute timeout as well
+		 */
+		ret = futex_init_timeout(FUTEX_WAIT_BITSET, flag_init, &ts, &time);
+		if (ret)
+			return ret;
+
+		futex_setup_timer(&time, &to, flag_clkid, 0);
+	}
+
+	futexv = kcalloc(nr_futexes, sizeof(*futexv), GFP_KERNEL);
+	if (!futexv) {
+		ret = -ENOMEM;
+		goto destroy_timer;
+	}
+
+	ret = futex_parse_waitv(futexv, waiters, nr_futexes);
+	if (!ret)
+		ret = futex_wait_multiple(futexv, nr_futexes, timeout ? &to : NULL);
+
+	kfree(futexv);
+
+destroy_timer:
+	if (timeout) {
+		hrtimer_cancel(&to.timer);
+		destroy_hrtimer_on_stack(&to.timer);
+	}
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(set_robust_list,
+		struct compat_robust_list_head __user *, head,
+		compat_size_t, len)
+{
+	if (unlikely(len != sizeof(*head)))
+		return -EINVAL;
+
+	current->compat_robust_list = head;
+
+	return 0;
+}
+
+COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid,
+			compat_uptr_t __user *, head_ptr,
+			compat_size_t __user *, len_ptr)
+{
+	struct compat_robust_list_head __user *head;
+	unsigned long ret;
+	struct task_struct *p;
+
+	rcu_read_lock();
+
+	ret = -ESRCH;
+	if (!pid)
+		p = current;
+	else {
+		p = find_task_by_vpid(pid);
+		if (!p)
+			goto err_unlock;
+	}
+
+	ret = -EPERM;
+	if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
+		goto err_unlock;
+
+	head = p->compat_robust_list;
+	rcu_read_unlock();
+
+	if (put_user(sizeof(*head), len_ptr))
+		return -EFAULT;
+	return put_user(ptr_to_compat(head), head_ptr);
+
+err_unlock:
+	rcu_read_unlock();
+
+	return ret;
+}
+#endif /* CONFIG_COMPAT */
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val,
+		const struct old_timespec32 __user *, utime, u32 __user *, uaddr2,
+		u32, val3)
+{
+	int ret, cmd = op & FUTEX_CMD_MASK;
+	ktime_t t, *tp = NULL;
+	struct timespec64 ts;
+
+	if (utime && futex_cmd_has_timeout(cmd)) {
+		if (get_old_timespec32(&ts, utime))
+			return -EFAULT;
+		ret = futex_init_timeout(cmd, op, &ts, &t);
+		if (ret)
+			return ret;
+		tp = &t;
+	}
+
+	return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
+}
+#endif /* CONFIG_COMPAT_32BIT_TIME */
+
diff --git a/kernel/futex/waitwake.c b/kernel/futex/waitwake.c
new file mode 100644
index 000000000..ba01b9408
--- /dev/null
+++ b/kernel/futex/waitwake.c
@@ -0,0 +1,708 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/sched/task.h>
+#include <linux/sched/signal.h>
+#include <linux/freezer.h>
+
+#include "futex.h"
+
+/*
+ * READ this before attempting to hack on futexes!
+ *
+ * Basic futex operation and ordering guarantees
+ * =============================================
+ *
+ * The waiter reads the futex value in user space and calls
+ * futex_wait(). This function computes the hash bucket and acquires
+ * the hash bucket lock. After that it reads the futex user space value
+ * again and verifies that the data has not changed. If it has not changed
+ * it enqueues itself into the hash bucket, releases the hash bucket lock
+ * and schedules.
+ *
+ * The waker side modifies the user space value of the futex and calls
+ * futex_wake(). This function computes the hash bucket and acquires the
+ * hash bucket lock. Then it looks for waiters on that futex in the hash
+ * bucket and wakes them.
+ *
+ * In futex wake up scenarios where no tasks are blocked on a futex, taking
+ * the hb spinlock can be avoided and simply return. In order for this
+ * optimization to work, ordering guarantees must exist so that the waiter
+ * being added to the list is acknowledged when the list is concurrently being
+ * checked by the waker, avoiding scenarios like the following:
+ *
+ * CPU 0                               CPU 1
+ * val = *futex;
+ * sys_futex(WAIT, futex, val);
+ *   futex_wait(futex, val);
+ *   uval = *futex;
+ *                                     *futex = newval;
+ *                                     sys_futex(WAKE, futex);
+ *                                       futex_wake(futex);
+ *                                       if (queue_empty())
+ *                                         return;
+ *   if (uval == val)
+ *      lock(hash_bucket(futex));
+ *      queue();
+ *     unlock(hash_bucket(futex));
+ *     schedule();
+ *
+ * This would cause the waiter on CPU 0 to wait forever because it
+ * missed the transition of the user space value from val to newval
+ * and the waker did not find the waiter in the hash bucket queue.
+ *
+ * The correct serialization ensures that a waiter either observes
+ * the changed user space value before blocking or is woken by a
+ * concurrent waker:
+ *
+ * CPU 0                                 CPU 1
+ * val = *futex;
+ * sys_futex(WAIT, futex, val);
+ *   futex_wait(futex, val);
+ *
+ *   waiters++; (a)
+ *   smp_mb(); (A) <-- paired with -.
+ *                                  |
+ *   lock(hash_bucket(futex));      |
+ *                                  |
+ *   uval = *futex;                 |
+ *                                  |        *futex = newval;
+ *                                  |        sys_futex(WAKE, futex);
+ *                                  |          futex_wake(futex);
+ *                                  |
+ *                                  `--------> smp_mb(); (B)
+ *   if (uval == val)
+ *     queue();
+ *     unlock(hash_bucket(futex));
+ *     schedule();                         if (waiters)
+ *                                           lock(hash_bucket(futex));
+ *   else                                    wake_waiters(futex);
+ *     waiters--; (b)                        unlock(hash_bucket(futex));
+ *
+ * Where (A) orders the waiters increment and the futex value read through
+ * atomic operations (see futex_hb_waiters_inc) and where (B) orders the write
+ * to futex and the waiters read (see futex_hb_waiters_pending()).
+ *
+ * This yields the following case (where X:=waiters, Y:=futex):
+ *
+ *	X = Y = 0
+ *
+ *	w[X]=1		w[Y]=1
+ *	MB		MB
+ *	r[Y]=y		r[X]=x
+ *
+ * Which guarantees that x==0 && y==0 is impossible; which translates back into
+ * the guarantee that we cannot both miss the futex variable change and the
+ * enqueue.
+ *
+ * Note that a new waiter is accounted for in (a) even when it is possible that
+ * the wait call can return error, in which case we backtrack from it in (b).
+ * Refer to the comment in futex_q_lock().
+ *
+ * Similarly, in order to account for waiters being requeued on another
+ * address we always increment the waiters for the destination bucket before
+ * acquiring the lock. It then decrements them again  after releasing it -
+ * the code that actually moves the futex(es) between hash buckets (requeue_futex)
+ * will do the additional required waiter count housekeeping. This is done for
+ * double_lock_hb() and double_unlock_hb(), respectively.
+ */
+
+/*
+ * The hash bucket lock must be held when this is called.
+ * Afterwards, the futex_q must not be accessed. Callers
+ * must ensure to later call wake_up_q() for the actual
+ * wakeups to occur.
+ */
+void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q)
+{
+	struct task_struct *p = q->task;
+
+	if (WARN(q->pi_state || q->rt_waiter, "refusing to wake PI futex\n"))
+		return;
+
+	get_task_struct(p);
+	__futex_unqueue(q);
+	/*
+	 * The waiting task can free the futex_q as soon as q->lock_ptr = NULL
+	 * is written, without taking any locks. This is possible in the event
+	 * of a spurious wakeup, for example. A memory barrier is required here
+	 * to prevent the following store to lock_ptr from getting ahead of the
+	 * plist_del in __futex_unqueue().
+	 */
+	smp_store_release(&q->lock_ptr, NULL);
+
+	/*
+	 * Queue the task for later wakeup for after we've released
+	 * the hb->lock.
+	 */
+	wake_q_add_safe(wake_q, p);
+}
+
+/*
+ * Wake up waiters matching bitset queued on this futex (uaddr).
+ */
+int futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
+{
+	struct futex_hash_bucket *hb;
+	struct futex_q *this, *next;
+	union futex_key key = FUTEX_KEY_INIT;
+	int ret;
+	DEFINE_WAKE_Q(wake_q);
+
+	if (!bitset)
+		return -EINVAL;
+
+	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, FUTEX_READ);
+	if (unlikely(ret != 0))
+		return ret;
+
+	hb = futex_hash(&key);
+
+	/* Make sure we really have tasks to wakeup */
+	if (!futex_hb_waiters_pending(hb))
+		return ret;
+
+	spin_lock(&hb->lock);
+
+	plist_for_each_entry_safe(this, next, &hb->chain, list) {
+		if (futex_match (&this->key, &key)) {
+			if (this->pi_state || this->rt_waiter) {
+				ret = -EINVAL;
+				break;
+			}
+
+			/* Check if one of the bits is set in both bitsets */
+			if (!(this->bitset & bitset))
+				continue;
+
+			futex_wake_mark(&wake_q, this);
+			if (++ret >= nr_wake)
+				break;
+		}
+	}
+
+	spin_unlock(&hb->lock);
+	wake_up_q(&wake_q);
+	return ret;
+}
+
+static int futex_atomic_op_inuser(unsigned int encoded_op, u32 __user *uaddr)
+{
+	unsigned int op =	  (encoded_op & 0x70000000) >> 28;
+	unsigned int cmp =	  (encoded_op & 0x0f000000) >> 24;
+	int oparg = sign_extend32((encoded_op & 0x00fff000) >> 12, 11);
+	int cmparg = sign_extend32(encoded_op & 0x00000fff, 11);
+	int oldval, ret;
+
+	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) {
+		if (oparg < 0 || oparg > 31) {
+			char comm[sizeof(current->comm)];
+			/*
+			 * kill this print and return -EINVAL when userspace
+			 * is sane again
+			 */
+			pr_info_ratelimited("futex_wake_op: %s tries to shift op by %d; fix this program\n",
+					get_task_comm(comm, current), oparg);
+			oparg &= 31;
+		}
+		oparg = 1 << oparg;
+	}
+
+	pagefault_disable();
+	ret = arch_futex_atomic_op_inuser(op, oparg, &oldval, uaddr);
+	pagefault_enable();
+	if (ret)
+		return ret;
+
+	switch (cmp) {
+	case FUTEX_OP_CMP_EQ:
+		return oldval == cmparg;
+	case FUTEX_OP_CMP_NE:
+		return oldval != cmparg;
+	case FUTEX_OP_CMP_LT:
+		return oldval < cmparg;
+	case FUTEX_OP_CMP_GE:
+		return oldval >= cmparg;
+	case FUTEX_OP_CMP_LE:
+		return oldval <= cmparg;
+	case FUTEX_OP_CMP_GT:
+		return oldval > cmparg;
+	default:
+		return -ENOSYS;
+	}
+}
+
+/*
+ * Wake up all waiters hashed on the physical page that is mapped
+ * to this virtual address:
+ */
+int futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
+		  int nr_wake, int nr_wake2, int op)
+{
+	union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT;
+	struct futex_hash_bucket *hb1, *hb2;
+	struct futex_q *this, *next;
+	int ret, op_ret;
+	DEFINE_WAKE_Q(wake_q);
+
+retry:
+	ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, FUTEX_READ);
+	if (unlikely(ret != 0))
+		return ret;
+	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, FUTEX_WRITE);
+	if (unlikely(ret != 0))
+		return ret;
+
+	hb1 = futex_hash(&key1);
+	hb2 = futex_hash(&key2);
+
+retry_private:
+	double_lock_hb(hb1, hb2);
+	op_ret = futex_atomic_op_inuser(op, uaddr2);
+	if (unlikely(op_ret < 0)) {
+		double_unlock_hb(hb1, hb2);
+
+		if (!IS_ENABLED(CONFIG_MMU) ||
+		    unlikely(op_ret != -EFAULT && op_ret != -EAGAIN)) {
+			/*
+			 * we don't get EFAULT from MMU faults if we don't have
+			 * an MMU, but we might get them from range checking
+			 */
+			ret = op_ret;
+			return ret;
+		}
+
+		if (op_ret == -EFAULT) {
+			ret = fault_in_user_writeable(uaddr2);
+			if (ret)
+				return ret;
+		}
+
+		cond_resched();
+		if (!(flags & FLAGS_SHARED))
+			goto retry_private;
+		goto retry;
+	}
+
+	plist_for_each_entry_safe(this, next, &hb1->chain, list) {
+		if (futex_match (&this->key, &key1)) {
+			if (this->pi_state || this->rt_waiter) {
+				ret = -EINVAL;
+				goto out_unlock;
+			}
+			futex_wake_mark(&wake_q, this);
+			if (++ret >= nr_wake)
+				break;
+		}
+	}
+
+	if (op_ret > 0) {
+		op_ret = 0;
+		plist_for_each_entry_safe(this, next, &hb2->chain, list) {
+			if (futex_match (&this->key, &key2)) {
+				if (this->pi_state || this->rt_waiter) {
+					ret = -EINVAL;
+					goto out_unlock;
+				}
+				futex_wake_mark(&wake_q, this);
+				if (++op_ret >= nr_wake2)
+					break;
+			}
+		}
+		ret += op_ret;
+	}
+
+out_unlock:
+	double_unlock_hb(hb1, hb2);
+	wake_up_q(&wake_q);
+	return ret;
+}
+
+static long futex_wait_restart(struct restart_block *restart);
+
+/**
+ * futex_wait_queue() - futex_queue() and wait for wakeup, timeout, or signal
+ * @hb:		the futex hash bucket, must be locked by the caller
+ * @q:		the futex_q to queue up on
+ * @timeout:	the prepared hrtimer_sleeper, or null for no timeout
+ */
+void futex_wait_queue(struct futex_hash_bucket *hb, struct futex_q *q,
+			    struct hrtimer_sleeper *timeout)
+{
+	/*
+	 * The task state is guaranteed to be set before another task can
+	 * wake it. set_current_state() is implemented using smp_store_mb() and
+	 * futex_queue() calls spin_unlock() upon completion, both serializing
+	 * access to the hash list and forcing another memory barrier.
+	 */
+	set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
+	futex_queue(q, hb);
+
+	/* Arm the timer */
+	if (timeout)
+		hrtimer_sleeper_start_expires(timeout, HRTIMER_MODE_ABS);
+
+	/*
+	 * If we have been removed from the hash list, then another task
+	 * has tried to wake us, and we can skip the call to schedule().
+	 */
+	if (likely(!plist_node_empty(&q->list))) {
+		/*
+		 * If the timer has already expired, current will already be
+		 * flagged for rescheduling. Only call schedule if there
+		 * is no timeout, or if it has yet to expire.
+		 */
+		if (!timeout || timeout->task)
+			schedule();
+	}
+	__set_current_state(TASK_RUNNING);
+}
+
+/**
+ * unqueue_multiple - Remove various futexes from their hash bucket
+ * @v:	   The list of futexes to unqueue
+ * @count: Number of futexes in the list
+ *
+ * Helper to unqueue a list of futexes. This can't fail.
+ *
+ * Return:
+ *  - >=0 - Index of the last futex that was awoken;
+ *  - -1  - No futex was awoken
+ */
+static int unqueue_multiple(struct futex_vector *v, int count)
+{
+	int ret = -1, i;
+
+	for (i = 0; i < count; i++) {
+		if (!futex_unqueue(&v[i].q))
+			ret = i;
+	}
+
+	return ret;
+}
+
+/**
+ * futex_wait_multiple_setup - Prepare to wait and enqueue multiple futexes
+ * @vs:		The futex list to wait on
+ * @count:	The size of the list
+ * @woken:	Index of the last woken futex, if any. Used to notify the
+ *		caller that it can return this index to userspace (return parameter)
+ *
+ * Prepare multiple futexes in a single step and enqueue them. This may fail if
+ * the futex list is invalid or if any futex was already awoken. On success the
+ * task is ready to interruptible sleep.
+ *
+ * Return:
+ *  -  1 - One of the futexes was woken by another thread
+ *  -  0 - Success
+ *  - <0 - -EFAULT, -EWOULDBLOCK or -EINVAL
+ */
+static int futex_wait_multiple_setup(struct futex_vector *vs, int count, int *woken)
+{
+	struct futex_hash_bucket *hb;
+	bool retry = false;
+	int ret, i;
+	u32 uval;
+
+	/*
+	 * Enqueuing multiple futexes is tricky, because we need to enqueue
+	 * each futex on the list before dealing with the next one to avoid
+	 * deadlocking on the hash bucket. But, before enqueuing, we need to
+	 * make sure that current->state is TASK_INTERRUPTIBLE, so we don't
+	 * lose any wake events, which cannot be done before the get_futex_key
+	 * of the next key, because it calls get_user_pages, which can sleep.
+	 * Thus, we fetch the list of futexes keys in two steps, by first
+	 * pinning all the memory keys in the futex key, and only then we read
+	 * each key and queue the corresponding futex.
+	 *
+	 * Private futexes doesn't need to recalculate hash in retry, so skip
+	 * get_futex_key() when retrying.
+	 */
+retry:
+	for (i = 0; i < count; i++) {
+		if ((vs[i].w.flags & FUTEX_PRIVATE_FLAG) && retry)
+			continue;
+
+		ret = get_futex_key(u64_to_user_ptr(vs[i].w.uaddr),
+				    !(vs[i].w.flags & FUTEX_PRIVATE_FLAG),
+				    &vs[i].q.key, FUTEX_READ);
+
+		if (unlikely(ret))
+			return ret;
+	}
+
+	set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
+
+	for (i = 0; i < count; i++) {
+		u32 __user *uaddr = (u32 __user *)(unsigned long)vs[i].w.uaddr;
+		struct futex_q *q = &vs[i].q;
+		u32 val = (u32)vs[i].w.val;
+
+		hb = futex_q_lock(q);
+		ret = futex_get_value_locked(&uval, uaddr);
+
+		if (!ret && uval == val) {
+			/*
+			 * The bucket lock can't be held while dealing with the
+			 * next futex. Queue each futex at this moment so hb can
+			 * be unlocked.
+			 */
+			futex_queue(q, hb);
+			continue;
+		}
+
+		futex_q_unlock(hb);
+		__set_current_state(TASK_RUNNING);
+
+		/*
+		 * Even if something went wrong, if we find out that a futex
+		 * was woken, we don't return error and return this index to
+		 * userspace
+		 */
+		*woken = unqueue_multiple(vs, i);
+		if (*woken >= 0)
+			return 1;
+
+		if (ret) {
+			/*
+			 * If we need to handle a page fault, we need to do so
+			 * without any lock and any enqueued futex (otherwise
+			 * we could lose some wakeup). So we do it here, after
+			 * undoing all the work done so far. In success, we
+			 * retry all the work.
+			 */
+			if (get_user(uval, uaddr))
+				return -EFAULT;
+
+			retry = true;
+			goto retry;
+		}
+
+		if (uval != val)
+			return -EWOULDBLOCK;
+	}
+
+	return 0;
+}
+
+/**
+ * futex_sleep_multiple - Check sleeping conditions and sleep
+ * @vs:    List of futexes to wait for
+ * @count: Length of vs
+ * @to:    Timeout
+ *
+ * Sleep if and only if the timeout hasn't expired and no futex on the list has
+ * been woken up.
+ */
+static void futex_sleep_multiple(struct futex_vector *vs, unsigned int count,
+				 struct hrtimer_sleeper *to)
+{
+	if (to && !to->task)
+		return;
+
+	for (; count; count--, vs++) {
+		if (!READ_ONCE(vs->q.lock_ptr))
+			return;
+	}
+
+	schedule();
+}
+
+/**
+ * futex_wait_multiple - Prepare to wait on and enqueue several futexes
+ * @vs:		The list of futexes to wait on
+ * @count:	The number of objects
+ * @to:		Timeout before giving up and returning to userspace
+ *
+ * Entry point for the FUTEX_WAIT_MULTIPLE futex operation, this function
+ * sleeps on a group of futexes and returns on the first futex that is
+ * wake, or after the timeout has elapsed.
+ *
+ * Return:
+ *  - >=0 - Hint to the futex that was awoken
+ *  - <0  - On error
+ */
+int futex_wait_multiple(struct futex_vector *vs, unsigned int count,
+			struct hrtimer_sleeper *to)
+{
+	int ret, hint = 0;
+
+	if (to)
+		hrtimer_sleeper_start_expires(to, HRTIMER_MODE_ABS);
+
+	while (1) {
+		ret = futex_wait_multiple_setup(vs, count, &hint);
+		if (ret) {
+			if (ret > 0) {
+				/* A futex was woken during setup */
+				ret = hint;
+			}
+			return ret;
+		}
+
+		futex_sleep_multiple(vs, count, to);
+
+		__set_current_state(TASK_RUNNING);
+
+		ret = unqueue_multiple(vs, count);
+		if (ret >= 0)
+			return ret;
+
+		if (to && !to->task)
+			return -ETIMEDOUT;
+		else if (signal_pending(current))
+			return -ERESTARTSYS;
+		/*
+		 * The final case is a spurious wakeup, for
+		 * which just retry.
+		 */
+	}
+}
+
+/**
+ * futex_wait_setup() - Prepare to wait on a futex
+ * @uaddr:	the futex userspace address
+ * @val:	the expected value
+ * @flags:	futex flags (FLAGS_SHARED, etc.)
+ * @q:		the associated futex_q
+ * @hb:		storage for hash_bucket pointer to be returned to caller
+ *
+ * Setup the futex_q and locate the hash_bucket.  Get the futex value and
+ * compare it with the expected value.  Handle atomic faults internally.
+ * Return with the hb lock held on success, and unlocked on failure.
+ *
+ * Return:
+ *  -  0 - uaddr contains val and hb has been locked;
+ *  - <1 - -EFAULT or -EWOULDBLOCK (uaddr does not contain val) and hb is unlocked
+ */
+int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags,
+		     struct futex_q *q, struct futex_hash_bucket **hb)
+{
+	u32 uval;
+	int ret;
+
+	/*
+	 * Access the page AFTER the hash-bucket is locked.
+	 * Order is important:
+	 *
+	 *   Userspace waiter: val = var; if (cond(val)) futex_wait(&var, val);
+	 *   Userspace waker:  if (cond(var)) { var = new; futex_wake(&var); }
+	 *
+	 * The basic logical guarantee of a futex is that it blocks ONLY
+	 * if cond(var) is known to be true at the time of blocking, for
+	 * any cond.  If we locked the hash-bucket after testing *uaddr, that
+	 * would open a race condition where we could block indefinitely with
+	 * cond(var) false, which would violate the guarantee.
+	 *
+	 * On the other hand, we insert q and release the hash-bucket only
+	 * after testing *uaddr.  This guarantees that futex_wait() will NOT
+	 * absorb a wakeup if *uaddr does not match the desired values
+	 * while the syscall executes.
+	 */
+retry:
+	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q->key, FUTEX_READ);
+	if (unlikely(ret != 0))
+		return ret;
+
+retry_private:
+	*hb = futex_q_lock(q);
+
+	ret = futex_get_value_locked(&uval, uaddr);
+
+	if (ret) {
+		futex_q_unlock(*hb);
+
+		ret = get_user(uval, uaddr);
+		if (ret)
+			return ret;
+
+		if (!(flags & FLAGS_SHARED))
+			goto retry_private;
+
+		goto retry;
+	}
+
+	if (uval != val) {
+		futex_q_unlock(*hb);
+		ret = -EWOULDBLOCK;
+	}
+
+	return ret;
+}
+
+int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val, ktime_t *abs_time, u32 bitset)
+{
+	struct hrtimer_sleeper timeout, *to;
+	struct restart_block *restart;
+	struct futex_hash_bucket *hb;
+	struct futex_q q = futex_q_init;
+	int ret;
+
+	if (!bitset)
+		return -EINVAL;
+	q.bitset = bitset;
+
+	to = futex_setup_timer(abs_time, &timeout, flags,
+			       current->timer_slack_ns);
+retry:
+	/*
+	 * Prepare to wait on uaddr. On success, it holds hb->lock and q
+	 * is initialized.
+	 */
+	ret = futex_wait_setup(uaddr, val, flags, &q, &hb);
+	if (ret)
+		goto out;
+
+	/* futex_queue and wait for wakeup, timeout, or a signal. */
+	futex_wait_queue(hb, &q, to);
+
+	/* If we were woken (and unqueued), we succeeded, whatever. */
+	ret = 0;
+	if (!futex_unqueue(&q))
+		goto out;
+	ret = -ETIMEDOUT;
+	if (to && !to->task)
+		goto out;
+
+	/*
+	 * We expect signal_pending(current), but we might be the
+	 * victim of a spurious wakeup as well.
+	 */
+	if (!signal_pending(current))
+		goto retry;
+
+	ret = -ERESTARTSYS;
+	if (!abs_time)
+		goto out;
+
+	restart = &current->restart_block;
+	restart->futex.uaddr = uaddr;
+	restart->futex.val = val;
+	restart->futex.time = *abs_time;
+	restart->futex.bitset = bitset;
+	restart->futex.flags = flags | FLAGS_HAS_TIMEOUT;
+
+	ret = set_restart_fn(restart, futex_wait_restart);
+
+out:
+	if (to) {
+		hrtimer_cancel(&to->timer);
+		destroy_hrtimer_on_stack(&to->timer);
+	}
+	return ret;
+}
+
+static long futex_wait_restart(struct restart_block *restart)
+{
+	u32 __user *uaddr = restart->futex.uaddr;
+	ktime_t t, *tp = NULL;
+
+	if (restart->futex.flags & FLAGS_HAS_TIMEOUT) {
+		t = restart->futex.time;
+		tp = &t;
+	}
+	restart->fn = do_no_restart_syscall;
+
+	return (long)futex_wait(uaddr, restart->futex.flags,
+				restart->futex.val, tp, restart->futex.bitset);
+}
+
diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig
new file mode 100644
index 000000000..04f4ebdc3
--- /dev/null
+++ b/kernel/gcov/Kconfig
@@ -0,0 +1,55 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "GCOV-based kernel profiling"
+
+config GCOV_KERNEL
+	bool "Enable gcov-based kernel profiling"
+	depends on DEBUG_FS
+	depends on !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR
+	select CONSTRUCTORS
+	default n
+	help
+	This option enables gcov-based code profiling (e.g. for code coverage
+	measurements).
+
+	If unsure, say N.
+
+	Additionally specify CONFIG_GCOV_PROFILE_ALL=y to get profiling data
+	for the entire kernel. To enable profiling for specific files or
+	directories, add a line similar to the following to the respective
+	Makefile:
+
+	For a single file (e.g. main.o):
+	        GCOV_PROFILE_main.o := y
+
+	For all files in one directory:
+	        GCOV_PROFILE := y
+
+	To exclude files from being profiled even when CONFIG_GCOV_PROFILE_ALL
+	is specified, use:
+
+	        GCOV_PROFILE_main.o := n
+	and:
+	        GCOV_PROFILE := n
+
+	Note that the debugfs filesystem has to be mounted to access
+	profiling data.
+
+config ARCH_HAS_GCOV_PROFILE_ALL
+	def_bool n
+
+config GCOV_PROFILE_ALL
+	bool "Profile entire Kernel"
+	depends on !COMPILE_TEST
+	depends on GCOV_KERNEL
+	depends on ARCH_HAS_GCOV_PROFILE_ALL
+	default n
+	help
+	This options activates profiling for the entire kernel.
+
+	If unsure, say N.
+
+	Note that a kernel compiled with profiling flags will be significantly
+	larger and run slower. Also be sure to exclude files from profiling
+	which are not linked to the kernel image to prevent linker errors.
+
+endmenu
diff --git a/kernel/gcov/Makefile b/kernel/gcov/Makefile
new file mode 100644
index 000000000..16f8ecc7d
--- /dev/null
+++ b/kernel/gcov/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+ccflags-y := -DSRCTREE='"$(srctree)"' -DOBJTREE='"$(objtree)"'
+
+obj-y := base.o fs.o
+obj-$(CONFIG_CC_IS_GCC) += gcc_base.o gcc_4_7.o
+obj-$(CONFIG_CC_IS_CLANG) += clang.o
diff --git a/kernel/gcov/base.c b/kernel/gcov/base.c
new file mode 100644
index 000000000..073a3738c
--- /dev/null
+++ b/kernel/gcov/base.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  This code maintains a list of active profiling data structures.
+ *
+ *    Copyright IBM Corp. 2009
+ *    Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
+ *
+ *    Uses gcc-internal data definitions.
+ *    Based on the gcov-kernel patch by:
+ *		 Hubertus Franke <frankeh@us.ibm.com>
+ *		 Nigel Hinds <nhinds@us.ibm.com>
+ *		 Rajan Ravindran <rajancr@us.ibm.com>
+ *		 Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
+ *		 Paul Larson
+ */
+
+#define pr_fmt(fmt)	"gcov: " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include "gcov.h"
+
+int gcov_events_enabled;
+DEFINE_MUTEX(gcov_lock);
+
+/**
+ * gcov_enable_events - enable event reporting through gcov_event()
+ *
+ * Turn on reporting of profiling data load/unload-events through the
+ * gcov_event() callback. Also replay all previous events once. This function
+ * is needed because some events are potentially generated too early for the
+ * callback implementation to handle them initially.
+ */
+void gcov_enable_events(void)
+{
+	struct gcov_info *info = NULL;
+
+	mutex_lock(&gcov_lock);
+	gcov_events_enabled = 1;
+
+	/* Perform event callback for previously registered entries. */
+	while ((info = gcov_info_next(info))) {
+		gcov_event(GCOV_ADD, info);
+		cond_resched();
+	}
+
+	mutex_unlock(&gcov_lock);
+}
+
+/**
+ * store_gcov_u32 - store 32 bit number in gcov format to buffer
+ * @buffer: target buffer or NULL
+ * @off: offset into the buffer
+ * @v: value to be stored
+ *
+ * Number format defined by gcc: numbers are recorded in the 32 bit
+ * unsigned binary form of the endianness of the machine generating the
+ * file. Returns the number of bytes stored. If @buffer is %NULL, doesn't
+ * store anything.
+ */
+size_t store_gcov_u32(void *buffer, size_t off, u32 v)
+{
+	u32 *data;
+
+	if (buffer) {
+		data = buffer + off;
+		*data = v;
+	}
+
+	return sizeof(*data);
+}
+
+/**
+ * store_gcov_u64 - store 64 bit number in gcov format to buffer
+ * @buffer: target buffer or NULL
+ * @off: offset into the buffer
+ * @v: value to be stored
+ *
+ * Number format defined by gcc: numbers are recorded in the 32 bit
+ * unsigned binary form of the endianness of the machine generating the
+ * file. 64 bit numbers are stored as two 32 bit numbers, the low part
+ * first. Returns the number of bytes stored. If @buffer is %NULL, doesn't store
+ * anything.
+ */
+size_t store_gcov_u64(void *buffer, size_t off, u64 v)
+{
+	u32 *data;
+
+	if (buffer) {
+		data = buffer + off;
+
+		data[0] = (v & 0xffffffffUL);
+		data[1] = (v >> 32);
+	}
+
+	return sizeof(*data) * 2;
+}
+
+#ifdef CONFIG_MODULES
+/* Update list and generate events when modules are unloaded. */
+static int gcov_module_notifier(struct notifier_block *nb, unsigned long event,
+				void *data)
+{
+	struct module *mod = data;
+	struct gcov_info *info = NULL;
+	struct gcov_info *prev = NULL;
+
+	if (event != MODULE_STATE_GOING)
+		return NOTIFY_OK;
+	mutex_lock(&gcov_lock);
+
+	/* Remove entries located in module from linked list. */
+	while ((info = gcov_info_next(info))) {
+		if (gcov_info_within_module(info, mod)) {
+			gcov_info_unlink(prev, info);
+			if (gcov_events_enabled)
+				gcov_event(GCOV_REMOVE, info);
+		} else
+			prev = info;
+	}
+
+	mutex_unlock(&gcov_lock);
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block gcov_nb = {
+	.notifier_call	= gcov_module_notifier,
+};
+
+static int __init gcov_init(void)
+{
+	return register_module_notifier(&gcov_nb);
+}
+device_initcall(gcov_init);
+#endif /* CONFIG_MODULES */
diff --git a/kernel/gcov/clang.c b/kernel/gcov/clang.c
new file mode 100644
index 000000000..7670a811a
--- /dev/null
+++ b/kernel/gcov/clang.c
@@ -0,0 +1,393 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Google, Inc.
+ * modified from kernel/gcov/gcc_4_7.c
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ *
+ * LLVM uses profiling data that's deliberately similar to GCC, but has a
+ * very different way of exporting that data.  LLVM calls llvm_gcov_init() once
+ * per module, and provides a couple of callbacks that we can use to ask for
+ * more data.
+ *
+ * We care about the "writeout" callback, which in turn calls back into
+ * compiler-rt/this module to dump all the gathered coverage data to disk:
+ *
+ *    llvm_gcda_start_file()
+ *      llvm_gcda_emit_function()
+ *      llvm_gcda_emit_arcs()
+ *      llvm_gcda_emit_function()
+ *      llvm_gcda_emit_arcs()
+ *      [... repeats for each function ...]
+ *    llvm_gcda_summary_info()
+ *    llvm_gcda_end_file()
+ *
+ * This design is much more stateless and unstructured than gcc's, and is
+ * intended to run at process exit.  This forces us to keep some local state
+ * about which module we're dealing with at the moment.  On the other hand, it
+ * also means we don't depend as much on how LLVM represents profiling data
+ * internally.
+ *
+ * See LLVM's lib/Transforms/Instrumentation/GCOVProfiling.cpp for more
+ * details on how this works, particularly GCOVProfiler::emitProfileArcs(),
+ * GCOVProfiler::insertCounterWriteout(), and
+ * GCOVProfiler::insertFlush().
+ */
+
+#define pr_fmt(fmt)	"gcov: " fmt
+
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/printk.h>
+#include <linux/ratelimit.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include "gcov.h"
+
+typedef void (*llvm_gcov_callback)(void);
+
+struct gcov_info {
+	struct list_head head;
+
+	const char *filename;
+	unsigned int version;
+	u32 checksum;
+
+	struct list_head functions;
+};
+
+struct gcov_fn_info {
+	struct list_head head;
+
+	u32 ident;
+	u32 checksum;
+	u32 cfg_checksum;
+
+	u32 num_counters;
+	u64 *counters;
+};
+
+static struct gcov_info *current_info;
+
+static LIST_HEAD(clang_gcov_list);
+
+void llvm_gcov_init(llvm_gcov_callback writeout, llvm_gcov_callback flush)
+{
+	struct gcov_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
+
+	if (!info)
+		return;
+
+	INIT_LIST_HEAD(&info->head);
+	INIT_LIST_HEAD(&info->functions);
+
+	mutex_lock(&gcov_lock);
+
+	list_add_tail(&info->head, &clang_gcov_list);
+	current_info = info;
+	writeout();
+	current_info = NULL;
+	if (gcov_events_enabled)
+		gcov_event(GCOV_ADD, info);
+
+	mutex_unlock(&gcov_lock);
+}
+EXPORT_SYMBOL(llvm_gcov_init);
+
+void llvm_gcda_start_file(const char *orig_filename, u32 version, u32 checksum)
+{
+	current_info->filename = orig_filename;
+	current_info->version = version;
+	current_info->checksum = checksum;
+}
+EXPORT_SYMBOL(llvm_gcda_start_file);
+
+void llvm_gcda_emit_function(u32 ident, u32 func_checksum, u32 cfg_checksum)
+{
+	struct gcov_fn_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
+
+	if (!info)
+		return;
+
+	INIT_LIST_HEAD(&info->head);
+	info->ident = ident;
+	info->checksum = func_checksum;
+	info->cfg_checksum = cfg_checksum;
+	list_add_tail(&info->head, &current_info->functions);
+}
+EXPORT_SYMBOL(llvm_gcda_emit_function);
+
+void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters)
+{
+	struct gcov_fn_info *info = list_last_entry(&current_info->functions,
+			struct gcov_fn_info, head);
+
+	info->num_counters = num_counters;
+	info->counters = counters;
+}
+EXPORT_SYMBOL(llvm_gcda_emit_arcs);
+
+void llvm_gcda_summary_info(void)
+{
+}
+EXPORT_SYMBOL(llvm_gcda_summary_info);
+
+void llvm_gcda_end_file(void)
+{
+}
+EXPORT_SYMBOL(llvm_gcda_end_file);
+
+/**
+ * gcov_info_filename - return info filename
+ * @info: profiling data set
+ */
+const char *gcov_info_filename(struct gcov_info *info)
+{
+	return info->filename;
+}
+
+/**
+ * gcov_info_version - return info version
+ * @info: profiling data set
+ */
+unsigned int gcov_info_version(struct gcov_info *info)
+{
+	return info->version;
+}
+
+/**
+ * gcov_info_next - return next profiling data set
+ * @info: profiling data set
+ *
+ * Returns next gcov_info following @info or first gcov_info in the chain if
+ * @info is %NULL.
+ */
+struct gcov_info *gcov_info_next(struct gcov_info *info)
+{
+	if (!info)
+		return list_first_entry_or_null(&clang_gcov_list,
+				struct gcov_info, head);
+	if (list_is_last(&info->head, &clang_gcov_list))
+		return NULL;
+	return list_next_entry(info, head);
+}
+
+/**
+ * gcov_info_link - link/add profiling data set to the list
+ * @info: profiling data set
+ */
+void gcov_info_link(struct gcov_info *info)
+{
+	list_add_tail(&info->head, &clang_gcov_list);
+}
+
+/**
+ * gcov_info_unlink - unlink/remove profiling data set from the list
+ * @prev: previous profiling data set
+ * @info: profiling data set
+ */
+void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
+{
+	/* Generic code unlinks while iterating. */
+	__list_del_entry(&info->head);
+}
+
+/**
+ * gcov_info_within_module - check if a profiling data set belongs to a module
+ * @info: profiling data set
+ * @mod: module
+ *
+ * Returns true if profiling data belongs module, false otherwise.
+ */
+bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
+{
+	return within_module((unsigned long)info->filename, mod);
+}
+
+/* Symbolic links to be created for each profiling data file. */
+const struct gcov_link gcov_link[] = {
+	{ OBJ_TREE, "gcno" },	/* Link to .gcno file in $(objtree). */
+	{ 0, NULL},
+};
+
+/**
+ * gcov_info_reset - reset profiling data to zero
+ * @info: profiling data set
+ */
+void gcov_info_reset(struct gcov_info *info)
+{
+	struct gcov_fn_info *fn;
+
+	list_for_each_entry(fn, &info->functions, head)
+		memset(fn->counters, 0,
+				sizeof(fn->counters[0]) * fn->num_counters);
+}
+
+/**
+ * gcov_info_is_compatible - check if profiling data can be added
+ * @info1: first profiling data set
+ * @info2: second profiling data set
+ *
+ * Returns non-zero if profiling data can be added, zero otherwise.
+ */
+int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
+{
+	struct gcov_fn_info *fn_ptr1 = list_first_entry_or_null(
+			&info1->functions, struct gcov_fn_info, head);
+	struct gcov_fn_info *fn_ptr2 = list_first_entry_or_null(
+			&info2->functions, struct gcov_fn_info, head);
+
+	if (info1->checksum != info2->checksum)
+		return false;
+	if (!fn_ptr1)
+		return fn_ptr1 == fn_ptr2;
+	while (!list_is_last(&fn_ptr1->head, &info1->functions) &&
+		!list_is_last(&fn_ptr2->head, &info2->functions)) {
+		if (fn_ptr1->checksum != fn_ptr2->checksum)
+			return false;
+		if (fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum)
+			return false;
+		fn_ptr1 = list_next_entry(fn_ptr1, head);
+		fn_ptr2 = list_next_entry(fn_ptr2, head);
+	}
+	return list_is_last(&fn_ptr1->head, &info1->functions) &&
+		list_is_last(&fn_ptr2->head, &info2->functions);
+}
+
+/**
+ * gcov_info_add - add up profiling data
+ * @dest: profiling data set to which data is added
+ * @source: profiling data set which is added
+ *
+ * Adds profiling counts of @source to @dest.
+ */
+void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
+{
+	struct gcov_fn_info *dfn_ptr;
+	struct gcov_fn_info *sfn_ptr = list_first_entry_or_null(&src->functions,
+			struct gcov_fn_info, head);
+
+	list_for_each_entry(dfn_ptr, &dst->functions, head) {
+		u32 i;
+
+		for (i = 0; i < sfn_ptr->num_counters; i++)
+			dfn_ptr->counters[i] += sfn_ptr->counters[i];
+
+		sfn_ptr = list_next_entry(sfn_ptr, head);
+	}
+}
+
+static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn)
+{
+	size_t cv_size; /* counter values size */
+	struct gcov_fn_info *fn_dup = kmemdup(fn, sizeof(*fn),
+			GFP_KERNEL);
+	if (!fn_dup)
+		return NULL;
+	INIT_LIST_HEAD(&fn_dup->head);
+
+	cv_size = fn->num_counters * sizeof(fn->counters[0]);
+	fn_dup->counters = kvmalloc(cv_size, GFP_KERNEL);
+	if (!fn_dup->counters) {
+		kfree(fn_dup);
+		return NULL;
+	}
+
+	memcpy(fn_dup->counters, fn->counters, cv_size);
+
+	return fn_dup;
+}
+
+/**
+ * gcov_info_dup - duplicate profiling data set
+ * @info: profiling data set to duplicate
+ *
+ * Return newly allocated duplicate on success, %NULL on error.
+ */
+struct gcov_info *gcov_info_dup(struct gcov_info *info)
+{
+	struct gcov_info *dup;
+	struct gcov_fn_info *fn;
+
+	dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
+	if (!dup)
+		return NULL;
+	INIT_LIST_HEAD(&dup->head);
+	INIT_LIST_HEAD(&dup->functions);
+	dup->filename = kstrdup(info->filename, GFP_KERNEL);
+	if (!dup->filename)
+		goto err;
+
+	list_for_each_entry(fn, &info->functions, head) {
+		struct gcov_fn_info *fn_dup = gcov_fn_info_dup(fn);
+
+		if (!fn_dup)
+			goto err;
+		list_add_tail(&fn_dup->head, &dup->functions);
+	}
+
+	return dup;
+
+err:
+	gcov_info_free(dup);
+	return NULL;
+}
+
+/**
+ * gcov_info_free - release memory for profiling data set duplicate
+ * @info: profiling data set duplicate to free
+ */
+void gcov_info_free(struct gcov_info *info)
+{
+	struct gcov_fn_info *fn, *tmp;
+
+	list_for_each_entry_safe(fn, tmp, &info->functions, head) {
+		kvfree(fn->counters);
+		list_del(&fn->head);
+		kfree(fn);
+	}
+	kfree(info->filename);
+	kfree(info);
+}
+
+/**
+ * convert_to_gcda - convert profiling data set to gcda file format
+ * @buffer: the buffer to store file data or %NULL if no data should be stored
+ * @info: profiling data set to be converted
+ *
+ * Returns the number of bytes that were/would have been stored into the buffer.
+ */
+size_t convert_to_gcda(char *buffer, struct gcov_info *info)
+{
+	struct gcov_fn_info *fi_ptr;
+	size_t pos = 0;
+
+	/* File header. */
+	pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
+	pos += store_gcov_u32(buffer, pos, info->version);
+	pos += store_gcov_u32(buffer, pos, info->checksum);
+
+	list_for_each_entry(fi_ptr, &info->functions, head) {
+		u32 i;
+
+		pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
+		pos += store_gcov_u32(buffer, pos, 3);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->checksum);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
+		pos += store_gcov_u32(buffer, pos, GCOV_TAG_COUNTER_BASE);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->num_counters * 2);
+		for (i = 0; i < fi_ptr->num_counters; i++)
+			pos += store_gcov_u64(buffer, pos, fi_ptr->counters[i]);
+	}
+
+	return pos;
+}
diff --git a/kernel/gcov/fs.c b/kernel/gcov/fs.c
new file mode 100644
index 000000000..5c3086cad
--- /dev/null
+++ b/kernel/gcov/fs.c
@@ -0,0 +1,882 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  This code exports profiling data as debugfs files to userspace.
+ *
+ *    Copyright IBM Corp. 2009
+ *    Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
+ *
+ *    Uses gcc-internal data definitions.
+ *    Based on the gcov-kernel patch by:
+ *		 Hubertus Franke <frankeh@us.ibm.com>
+ *		 Nigel Hinds <nhinds@us.ibm.com>
+ *		 Rajan Ravindran <rajancr@us.ibm.com>
+ *		 Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
+ *		 Paul Larson
+ *		 Yi CDL Yang
+ */
+
+#define pr_fmt(fmt)	"gcov: " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/seq_file.h>
+#include <linux/mm.h>
+#include "gcov.h"
+
+/**
+ * struct gcov_node - represents a debugfs entry
+ * @list: list head for child node list
+ * @children: child nodes
+ * @all: list head for list of all nodes
+ * @parent: parent node
+ * @loaded_info: array of pointers to profiling data sets for loaded object
+ *   files.
+ * @num_loaded: number of profiling data sets for loaded object files.
+ * @unloaded_info: accumulated copy of profiling data sets for unloaded
+ *   object files. Used only when gcov_persist=1.
+ * @dentry: main debugfs entry, either a directory or data file
+ * @links: associated symbolic links
+ * @name: data file basename
+ *
+ * struct gcov_node represents an entity within the gcov/ subdirectory
+ * of debugfs. There are directory and data file nodes. The latter represent
+ * the actual synthesized data file plus any associated symbolic links which
+ * are needed by the gcov tool to work correctly.
+ */
+struct gcov_node {
+	struct list_head list;
+	struct list_head children;
+	struct list_head all;
+	struct gcov_node *parent;
+	struct gcov_info **loaded_info;
+	struct gcov_info *unloaded_info;
+	struct dentry *dentry;
+	struct dentry **links;
+	int num_loaded;
+	char name[];
+};
+
+static const char objtree[] = OBJTREE;
+static const char srctree[] = SRCTREE;
+static struct gcov_node root_node;
+static LIST_HEAD(all_head);
+static DEFINE_MUTEX(node_lock);
+
+/* If non-zero, keep copies of profiling data for unloaded modules. */
+static int gcov_persist = 1;
+
+static int __init gcov_persist_setup(char *str)
+{
+	unsigned long val;
+
+	if (kstrtoul(str, 0, &val)) {
+		pr_warn("invalid gcov_persist parameter '%s'\n", str);
+		return 0;
+	}
+	gcov_persist = val;
+	pr_info("setting gcov_persist to %d\n", gcov_persist);
+
+	return 1;
+}
+__setup("gcov_persist=", gcov_persist_setup);
+
+#define ITER_STRIDE	PAGE_SIZE
+
+/**
+ * struct gcov_iterator - specifies current file position in logical records
+ * @info: associated profiling data
+ * @buffer: buffer containing file data
+ * @size: size of buffer
+ * @pos: current position in file
+ */
+struct gcov_iterator {
+	struct gcov_info *info;
+	size_t size;
+	loff_t pos;
+	char buffer[];
+};
+
+/**
+ * gcov_iter_new - allocate and initialize profiling data iterator
+ * @info: profiling data set to be iterated
+ *
+ * Return file iterator on success, %NULL otherwise.
+ */
+static struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
+{
+	struct gcov_iterator *iter;
+	size_t size;
+
+	/* Dry-run to get the actual buffer size. */
+	size = convert_to_gcda(NULL, info);
+
+	iter = kvmalloc(struct_size(iter, buffer, size), GFP_KERNEL);
+	if (!iter)
+		return NULL;
+
+	iter->info = info;
+	iter->size = size;
+	convert_to_gcda(iter->buffer, info);
+
+	return iter;
+}
+
+
+/**
+ * gcov_iter_free - free iterator data
+ * @iter: file iterator
+ */
+static void gcov_iter_free(struct gcov_iterator *iter)
+{
+	kvfree(iter);
+}
+
+/**
+ * gcov_iter_get_info - return profiling data set for given file iterator
+ * @iter: file iterator
+ */
+static struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter)
+{
+	return iter->info;
+}
+
+/**
+ * gcov_iter_start - reset file iterator to starting position
+ * @iter: file iterator
+ */
+static void gcov_iter_start(struct gcov_iterator *iter)
+{
+	iter->pos = 0;
+}
+
+/**
+ * gcov_iter_next - advance file iterator to next logical record
+ * @iter: file iterator
+ *
+ * Return zero if new position is valid, non-zero if iterator has reached end.
+ */
+static int gcov_iter_next(struct gcov_iterator *iter)
+{
+	if (iter->pos < iter->size)
+		iter->pos += ITER_STRIDE;
+
+	if (iter->pos >= iter->size)
+		return -EINVAL;
+
+	return 0;
+}
+
+/**
+ * gcov_iter_write - write data for current pos to seq_file
+ * @iter: file iterator
+ * @seq: seq_file handle
+ *
+ * Return zero on success, non-zero otherwise.
+ */
+static int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq)
+{
+	size_t len;
+
+	if (iter->pos >= iter->size)
+		return -EINVAL;
+
+	len = ITER_STRIDE;
+	if (iter->pos + len > iter->size)
+		len = iter->size - iter->pos;
+
+	seq_write(seq, iter->buffer + iter->pos, len);
+
+	return 0;
+}
+
+/*
+ * seq_file.start() implementation for gcov data files. Note that the
+ * gcov_iterator interface is designed to be more restrictive than seq_file
+ * (no start from arbitrary position, etc.), to simplify the iterator
+ * implementation.
+ */
+static void *gcov_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	loff_t i;
+
+	gcov_iter_start(seq->private);
+	for (i = 0; i < *pos; i++) {
+		if (gcov_iter_next(seq->private))
+			return NULL;
+	}
+	return seq->private;
+}
+
+/* seq_file.next() implementation for gcov data files. */
+static void *gcov_seq_next(struct seq_file *seq, void *data, loff_t *pos)
+{
+	struct gcov_iterator *iter = data;
+
+	(*pos)++;
+	if (gcov_iter_next(iter))
+		return NULL;
+
+	return iter;
+}
+
+/* seq_file.show() implementation for gcov data files. */
+static int gcov_seq_show(struct seq_file *seq, void *data)
+{
+	struct gcov_iterator *iter = data;
+
+	if (gcov_iter_write(iter, seq))
+		return -EINVAL;
+	return 0;
+}
+
+static void gcov_seq_stop(struct seq_file *seq, void *data)
+{
+	/* Unused. */
+}
+
+static const struct seq_operations gcov_seq_ops = {
+	.start	= gcov_seq_start,
+	.next	= gcov_seq_next,
+	.show	= gcov_seq_show,
+	.stop	= gcov_seq_stop,
+};
+
+/*
+ * Return a profiling data set associated with the given node. This is
+ * either a data set for a loaded object file or a data set copy in case
+ * all associated object files have been unloaded.
+ */
+static struct gcov_info *get_node_info(struct gcov_node *node)
+{
+	if (node->num_loaded > 0)
+		return node->loaded_info[0];
+
+	return node->unloaded_info;
+}
+
+/*
+ * Return a newly allocated profiling data set which contains the sum of
+ * all profiling data associated with the given node.
+ */
+static struct gcov_info *get_accumulated_info(struct gcov_node *node)
+{
+	struct gcov_info *info;
+	int i = 0;
+
+	if (node->unloaded_info)
+		info = gcov_info_dup(node->unloaded_info);
+	else
+		info = gcov_info_dup(node->loaded_info[i++]);
+	if (!info)
+		return NULL;
+	for (; i < node->num_loaded; i++)
+		gcov_info_add(info, node->loaded_info[i]);
+
+	return info;
+}
+
+/*
+ * open() implementation for gcov data files. Create a copy of the profiling
+ * data set and initialize the iterator and seq_file interface.
+ */
+static int gcov_seq_open(struct inode *inode, struct file *file)
+{
+	struct gcov_node *node = inode->i_private;
+	struct gcov_iterator *iter;
+	struct seq_file *seq;
+	struct gcov_info *info;
+	int rc = -ENOMEM;
+
+	mutex_lock(&node_lock);
+	/*
+	 * Read from a profiling data copy to minimize reference tracking
+	 * complexity and concurrent access and to keep accumulating multiple
+	 * profiling data sets associated with one node simple.
+	 */
+	info = get_accumulated_info(node);
+	if (!info)
+		goto out_unlock;
+	iter = gcov_iter_new(info);
+	if (!iter)
+		goto err_free_info;
+	rc = seq_open(file, &gcov_seq_ops);
+	if (rc)
+		goto err_free_iter_info;
+	seq = file->private_data;
+	seq->private = iter;
+out_unlock:
+	mutex_unlock(&node_lock);
+	return rc;
+
+err_free_iter_info:
+	gcov_iter_free(iter);
+err_free_info:
+	gcov_info_free(info);
+	goto out_unlock;
+}
+
+/*
+ * release() implementation for gcov data files. Release resources allocated
+ * by open().
+ */
+static int gcov_seq_release(struct inode *inode, struct file *file)
+{
+	struct gcov_iterator *iter;
+	struct gcov_info *info;
+	struct seq_file *seq;
+
+	seq = file->private_data;
+	iter = seq->private;
+	info = gcov_iter_get_info(iter);
+	gcov_iter_free(iter);
+	gcov_info_free(info);
+	seq_release(inode, file);
+
+	return 0;
+}
+
+/*
+ * Find a node by the associated data file name. Needs to be called with
+ * node_lock held.
+ */
+static struct gcov_node *get_node_by_name(const char *name)
+{
+	struct gcov_node *node;
+	struct gcov_info *info;
+
+	list_for_each_entry(node, &all_head, all) {
+		info = get_node_info(node);
+		if (info && (strcmp(gcov_info_filename(info), name) == 0))
+			return node;
+	}
+
+	return NULL;
+}
+
+/*
+ * Reset all profiling data associated with the specified node.
+ */
+static void reset_node(struct gcov_node *node)
+{
+	int i;
+
+	if (node->unloaded_info)
+		gcov_info_reset(node->unloaded_info);
+	for (i = 0; i < node->num_loaded; i++)
+		gcov_info_reset(node->loaded_info[i]);
+}
+
+static void remove_node(struct gcov_node *node);
+
+/*
+ * write() implementation for gcov data files. Reset profiling data for the
+ * corresponding file. If all associated object files have been unloaded,
+ * remove the debug fs node as well.
+ */
+static ssize_t gcov_seq_write(struct file *file, const char __user *addr,
+			      size_t len, loff_t *pos)
+{
+	struct seq_file *seq;
+	struct gcov_info *info;
+	struct gcov_node *node;
+
+	seq = file->private_data;
+	info = gcov_iter_get_info(seq->private);
+	mutex_lock(&node_lock);
+	node = get_node_by_name(gcov_info_filename(info));
+	if (node) {
+		/* Reset counts or remove node for unloaded modules. */
+		if (node->num_loaded == 0)
+			remove_node(node);
+		else
+			reset_node(node);
+	}
+	/* Reset counts for open file. */
+	gcov_info_reset(info);
+	mutex_unlock(&node_lock);
+
+	return len;
+}
+
+/*
+ * Given a string <path> representing a file path of format:
+ *   path/to/file.gcda
+ * construct and return a new string:
+ *   <dir/>path/to/file.<ext>
+ */
+static char *link_target(const char *dir, const char *path, const char *ext)
+{
+	char *target;
+	char *old_ext;
+	char *copy;
+
+	copy = kstrdup(path, GFP_KERNEL);
+	if (!copy)
+		return NULL;
+	old_ext = strrchr(copy, '.');
+	if (old_ext)
+		*old_ext = '\0';
+	if (dir)
+		target = kasprintf(GFP_KERNEL, "%s/%s.%s", dir, copy, ext);
+	else
+		target = kasprintf(GFP_KERNEL, "%s.%s", copy, ext);
+	kfree(copy);
+
+	return target;
+}
+
+/*
+ * Construct a string representing the symbolic link target for the given
+ * gcov data file name and link type. Depending on the link type and the
+ * location of the data file, the link target can either point to a
+ * subdirectory of srctree, objtree or in an external location.
+ */
+static char *get_link_target(const char *filename, const struct gcov_link *ext)
+{
+	const char *rel;
+	char *result;
+
+	if (strncmp(filename, objtree, strlen(objtree)) == 0) {
+		rel = filename + strlen(objtree) + 1;
+		if (ext->dir == SRC_TREE)
+			result = link_target(srctree, rel, ext->ext);
+		else
+			result = link_target(objtree, rel, ext->ext);
+	} else {
+		/* External compilation. */
+		result = link_target(NULL, filename, ext->ext);
+	}
+
+	return result;
+}
+
+#define SKEW_PREFIX	".tmp_"
+
+/*
+ * For a filename .tmp_filename.ext return filename.ext. Needed to compensate
+ * for filename skewing caused by the mod-versioning mechanism.
+ */
+static const char *deskew(const char *basename)
+{
+	if (strncmp(basename, SKEW_PREFIX, sizeof(SKEW_PREFIX) - 1) == 0)
+		return basename + sizeof(SKEW_PREFIX) - 1;
+	return basename;
+}
+
+/*
+ * Create links to additional files (usually .c and .gcno files) which the
+ * gcov tool expects to find in the same directory as the gcov data file.
+ */
+static void add_links(struct gcov_node *node, struct dentry *parent)
+{
+	const char *basename;
+	char *target;
+	int num;
+	int i;
+
+	for (num = 0; gcov_link[num].ext; num++)
+		/* Nothing. */;
+	node->links = kcalloc(num, sizeof(struct dentry *), GFP_KERNEL);
+	if (!node->links)
+		return;
+	for (i = 0; i < num; i++) {
+		target = get_link_target(
+				gcov_info_filename(get_node_info(node)),
+				&gcov_link[i]);
+		if (!target)
+			goto out_err;
+		basename = kbasename(target);
+		if (basename == target)
+			goto out_err;
+		node->links[i] = debugfs_create_symlink(deskew(basename),
+							parent,	target);
+		kfree(target);
+	}
+
+	return;
+out_err:
+	kfree(target);
+	while (i-- > 0)
+		debugfs_remove(node->links[i]);
+	kfree(node->links);
+	node->links = NULL;
+}
+
+static const struct file_operations gcov_data_fops = {
+	.open		= gcov_seq_open,
+	.release	= gcov_seq_release,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.write		= gcov_seq_write,
+};
+
+/* Basic initialization of a new node. */
+static void init_node(struct gcov_node *node, struct gcov_info *info,
+		      const char *name, struct gcov_node *parent)
+{
+	INIT_LIST_HEAD(&node->list);
+	INIT_LIST_HEAD(&node->children);
+	INIT_LIST_HEAD(&node->all);
+	if (node->loaded_info) {
+		node->loaded_info[0] = info;
+		node->num_loaded = 1;
+	}
+	node->parent = parent;
+	if (name)
+		strcpy(node->name, name);
+}
+
+/*
+ * Create a new node and associated debugfs entry. Needs to be called with
+ * node_lock held.
+ */
+static struct gcov_node *new_node(struct gcov_node *parent,
+				  struct gcov_info *info, const char *name)
+{
+	struct gcov_node *node;
+
+	node = kzalloc(sizeof(struct gcov_node) + strlen(name) + 1, GFP_KERNEL);
+	if (!node)
+		goto err_nomem;
+	if (info) {
+		node->loaded_info = kcalloc(1, sizeof(struct gcov_info *),
+					   GFP_KERNEL);
+		if (!node->loaded_info)
+			goto err_nomem;
+	}
+	init_node(node, info, name, parent);
+	/* Differentiate between gcov data file nodes and directory nodes. */
+	if (info) {
+		node->dentry = debugfs_create_file(deskew(node->name), 0600,
+					parent->dentry, node, &gcov_data_fops);
+	} else
+		node->dentry = debugfs_create_dir(node->name, parent->dentry);
+	if (info)
+		add_links(node, parent->dentry);
+	list_add(&node->list, &parent->children);
+	list_add(&node->all, &all_head);
+
+	return node;
+
+err_nomem:
+	kfree(node);
+	pr_warn("out of memory\n");
+	return NULL;
+}
+
+/* Remove symbolic links associated with node. */
+static void remove_links(struct gcov_node *node)
+{
+	int i;
+
+	if (!node->links)
+		return;
+	for (i = 0; gcov_link[i].ext; i++)
+		debugfs_remove(node->links[i]);
+	kfree(node->links);
+	node->links = NULL;
+}
+
+/*
+ * Remove node from all lists and debugfs and release associated resources.
+ * Needs to be called with node_lock held.
+ */
+static void release_node(struct gcov_node *node)
+{
+	list_del(&node->list);
+	list_del(&node->all);
+	debugfs_remove(node->dentry);
+	remove_links(node);
+	kfree(node->loaded_info);
+	if (node->unloaded_info)
+		gcov_info_free(node->unloaded_info);
+	kfree(node);
+}
+
+/* Release node and empty parents. Needs to be called with node_lock held. */
+static void remove_node(struct gcov_node *node)
+{
+	struct gcov_node *parent;
+
+	while ((node != &root_node) && list_empty(&node->children)) {
+		parent = node->parent;
+		release_node(node);
+		node = parent;
+	}
+}
+
+/*
+ * Find child node with given basename. Needs to be called with node_lock
+ * held.
+ */
+static struct gcov_node *get_child_by_name(struct gcov_node *parent,
+					   const char *name)
+{
+	struct gcov_node *node;
+
+	list_for_each_entry(node, &parent->children, list) {
+		if (strcmp(node->name, name) == 0)
+			return node;
+	}
+
+	return NULL;
+}
+
+/*
+ * write() implementation for reset file. Reset all profiling data to zero
+ * and remove nodes for which all associated object files are unloaded.
+ */
+static ssize_t reset_write(struct file *file, const char __user *addr,
+			   size_t len, loff_t *pos)
+{
+	struct gcov_node *node;
+
+	mutex_lock(&node_lock);
+restart:
+	list_for_each_entry(node, &all_head, all) {
+		if (node->num_loaded > 0)
+			reset_node(node);
+		else if (list_empty(&node->children)) {
+			remove_node(node);
+			/* Several nodes may have gone - restart loop. */
+			goto restart;
+		}
+	}
+	mutex_unlock(&node_lock);
+
+	return len;
+}
+
+/* read() implementation for reset file. Unused. */
+static ssize_t reset_read(struct file *file, char __user *addr, size_t len,
+			  loff_t *pos)
+{
+	/* Allow read operation so that a recursive copy won't fail. */
+	return 0;
+}
+
+static const struct file_operations gcov_reset_fops = {
+	.write	= reset_write,
+	.read	= reset_read,
+	.llseek = noop_llseek,
+};
+
+/*
+ * Create a node for a given profiling data set and add it to all lists and
+ * debugfs. Needs to be called with node_lock held.
+ */
+static void add_node(struct gcov_info *info)
+{
+	char *filename;
+	char *curr;
+	char *next;
+	struct gcov_node *parent;
+	struct gcov_node *node;
+
+	filename = kstrdup(gcov_info_filename(info), GFP_KERNEL);
+	if (!filename)
+		return;
+	parent = &root_node;
+	/* Create directory nodes along the path. */
+	for (curr = filename; (next = strchr(curr, '/')); curr = next + 1) {
+		if (curr == next)
+			continue;
+		*next = 0;
+		if (strcmp(curr, ".") == 0)
+			continue;
+		if (strcmp(curr, "..") == 0) {
+			if (!parent->parent)
+				goto err_remove;
+			parent = parent->parent;
+			continue;
+		}
+		node = get_child_by_name(parent, curr);
+		if (!node) {
+			node = new_node(parent, NULL, curr);
+			if (!node)
+				goto err_remove;
+		}
+		parent = node;
+	}
+	/* Create file node. */
+	node = new_node(parent, info, curr);
+	if (!node)
+		goto err_remove;
+out:
+	kfree(filename);
+	return;
+
+err_remove:
+	remove_node(parent);
+	goto out;
+}
+
+/*
+ * Associate a profiling data set with an existing node. Needs to be called
+ * with node_lock held.
+ */
+static void add_info(struct gcov_node *node, struct gcov_info *info)
+{
+	struct gcov_info **loaded_info;
+	int num = node->num_loaded;
+
+	/*
+	 * Prepare new array. This is done first to simplify cleanup in
+	 * case the new data set is incompatible, the node only contains
+	 * unloaded data sets and there's not enough memory for the array.
+	 */
+	loaded_info = kcalloc(num + 1, sizeof(struct gcov_info *), GFP_KERNEL);
+	if (!loaded_info) {
+		pr_warn("could not add '%s' (out of memory)\n",
+			gcov_info_filename(info));
+		return;
+	}
+	memcpy(loaded_info, node->loaded_info,
+	       num * sizeof(struct gcov_info *));
+	loaded_info[num] = info;
+	/* Check if the new data set is compatible. */
+	if (num == 0) {
+		/*
+		 * A module was unloaded, modified and reloaded. The new
+		 * data set replaces the copy of the last one.
+		 */
+		if (!gcov_info_is_compatible(node->unloaded_info, info)) {
+			pr_warn("discarding saved data for %s "
+				"(incompatible version)\n",
+				gcov_info_filename(info));
+			gcov_info_free(node->unloaded_info);
+			node->unloaded_info = NULL;
+		}
+	} else {
+		/*
+		 * Two different versions of the same object file are loaded.
+		 * The initial one takes precedence.
+		 */
+		if (!gcov_info_is_compatible(node->loaded_info[0], info)) {
+			pr_warn("could not add '%s' (incompatible "
+				"version)\n", gcov_info_filename(info));
+			kfree(loaded_info);
+			return;
+		}
+	}
+	/* Overwrite previous array. */
+	kfree(node->loaded_info);
+	node->loaded_info = loaded_info;
+	node->num_loaded = num + 1;
+}
+
+/*
+ * Return the index of a profiling data set associated with a node.
+ */
+static int get_info_index(struct gcov_node *node, struct gcov_info *info)
+{
+	int i;
+
+	for (i = 0; i < node->num_loaded; i++) {
+		if (node->loaded_info[i] == info)
+			return i;
+	}
+	return -ENOENT;
+}
+
+/*
+ * Save the data of a profiling data set which is being unloaded.
+ */
+static void save_info(struct gcov_node *node, struct gcov_info *info)
+{
+	if (node->unloaded_info)
+		gcov_info_add(node->unloaded_info, info);
+	else {
+		node->unloaded_info = gcov_info_dup(info);
+		if (!node->unloaded_info) {
+			pr_warn("could not save data for '%s' "
+				"(out of memory)\n",
+				gcov_info_filename(info));
+		}
+	}
+}
+
+/*
+ * Disassociate a profiling data set from a node. Needs to be called with
+ * node_lock held.
+ */
+static void remove_info(struct gcov_node *node, struct gcov_info *info)
+{
+	int i;
+
+	i = get_info_index(node, info);
+	if (i < 0) {
+		pr_warn("could not remove '%s' (not found)\n",
+			gcov_info_filename(info));
+		return;
+	}
+	if (gcov_persist)
+		save_info(node, info);
+	/* Shrink array. */
+	node->loaded_info[i] = node->loaded_info[node->num_loaded - 1];
+	node->num_loaded--;
+	if (node->num_loaded > 0)
+		return;
+	/* Last loaded data set was removed. */
+	kfree(node->loaded_info);
+	node->loaded_info = NULL;
+	node->num_loaded = 0;
+	if (!node->unloaded_info)
+		remove_node(node);
+}
+
+/*
+ * Callback to create/remove profiling files when code compiled with
+ * -fprofile-arcs is loaded/unloaded.
+ */
+void gcov_event(enum gcov_action action, struct gcov_info *info)
+{
+	struct gcov_node *node;
+
+	mutex_lock(&node_lock);
+	node = get_node_by_name(gcov_info_filename(info));
+	switch (action) {
+	case GCOV_ADD:
+		if (node)
+			add_info(node, info);
+		else
+			add_node(info);
+		break;
+	case GCOV_REMOVE:
+		if (node)
+			remove_info(node, info);
+		else {
+			pr_warn("could not remove '%s' (not found)\n",
+				gcov_info_filename(info));
+		}
+		break;
+	}
+	mutex_unlock(&node_lock);
+}
+
+/* Create debugfs entries. */
+static __init int gcov_fs_init(void)
+{
+	init_node(&root_node, NULL, NULL, NULL);
+	/*
+	 * /sys/kernel/debug/gcov will be parent for the reset control file
+	 * and all profiling files.
+	 */
+	root_node.dentry = debugfs_create_dir("gcov", NULL);
+	/*
+	 * Create reset file which resets all profiling counts when written
+	 * to.
+	 */
+	debugfs_create_file("reset", 0600, root_node.dentry, NULL,
+			    &gcov_reset_fops);
+	/* Replay previous events to get our fs hierarchy up-to-date. */
+	gcov_enable_events();
+	return 0;
+}
+device_initcall(gcov_fs_init);
diff --git a/kernel/gcov/gcc_4_7.c b/kernel/gcov/gcc_4_7.c
new file mode 100644
index 000000000..74a4ef1da
--- /dev/null
+++ b/kernel/gcov/gcc_4_7.c
@@ -0,0 +1,436 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  This code provides functions to handle gcc's profiling data format
+ *  introduced with gcc 4.7.
+ *
+ *  This file is based heavily on gcc_3_4.c file.
+ *
+ *  For a better understanding, refer to gcc source:
+ *  gcc/gcov-io.h
+ *  libgcc/libgcov.c
+ *
+ *  Uses gcc-internal data definitions.
+ */
+
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include "gcov.h"
+
+#if (__GNUC__ >= 10)
+#define GCOV_COUNTERS			8
+#elif (__GNUC__ >= 7)
+#define GCOV_COUNTERS			9
+#elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)
+#define GCOV_COUNTERS			10
+#else
+#define GCOV_COUNTERS			9
+#endif
+
+#define GCOV_TAG_FUNCTION_LENGTH	3
+
+/* Since GCC 12.1 sizes are in BYTES and not in WORDS (4B). */
+#if (__GNUC__ >= 12)
+#define GCOV_UNIT_SIZE				4
+#else
+#define GCOV_UNIT_SIZE				1
+#endif
+
+static struct gcov_info *gcov_info_head;
+
+/**
+ * struct gcov_ctr_info - information about counters for a single function
+ * @num: number of counter values for this type
+ * @values: array of counter values for this type
+ *
+ * This data is generated by gcc during compilation and doesn't change
+ * at run-time with the exception of the values array.
+ */
+struct gcov_ctr_info {
+	unsigned int num;
+	gcov_type *values;
+};
+
+/**
+ * struct gcov_fn_info - profiling meta data per function
+ * @key: comdat key
+ * @ident: unique ident of function
+ * @lineno_checksum: function lineo_checksum
+ * @cfg_checksum: function cfg checksum
+ * @ctrs: instrumented counters
+ *
+ * This data is generated by gcc during compilation and doesn't change
+ * at run-time.
+ *
+ * Information about a single function.  This uses the trailing array
+ * idiom. The number of counters is determined from the merge pointer
+ * array in gcov_info.  The key is used to detect which of a set of
+ * comdat functions was selected -- it points to the gcov_info object
+ * of the object file containing the selected comdat function.
+ */
+struct gcov_fn_info {
+	const struct gcov_info *key;
+	unsigned int ident;
+	unsigned int lineno_checksum;
+	unsigned int cfg_checksum;
+	struct gcov_ctr_info ctrs[];
+};
+
+/**
+ * struct gcov_info - profiling data per object file
+ * @version: gcov version magic indicating the gcc version used for compilation
+ * @next: list head for a singly-linked list
+ * @stamp: uniquifying time stamp
+ * @checksum: unique object checksum
+ * @filename: name of the associated gcov data file
+ * @merge: merge functions (null for unused counter type)
+ * @n_functions: number of instrumented functions
+ * @functions: pointer to pointers to function information
+ *
+ * This data is generated by gcc during compilation and doesn't change
+ * at run-time with the exception of the next pointer.
+ */
+struct gcov_info {
+	unsigned int version;
+	struct gcov_info *next;
+	unsigned int stamp;
+ /* Since GCC 12.1 a checksum field is added. */
+#if (__GNUC__ >= 12)
+	unsigned int checksum;
+#endif
+	const char *filename;
+	void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int);
+	unsigned int n_functions;
+	struct gcov_fn_info **functions;
+};
+
+/**
+ * gcov_info_filename - return info filename
+ * @info: profiling data set
+ */
+const char *gcov_info_filename(struct gcov_info *info)
+{
+	return info->filename;
+}
+
+/**
+ * gcov_info_version - return info version
+ * @info: profiling data set
+ */
+unsigned int gcov_info_version(struct gcov_info *info)
+{
+	return info->version;
+}
+
+/**
+ * gcov_info_next - return next profiling data set
+ * @info: profiling data set
+ *
+ * Returns next gcov_info following @info or first gcov_info in the chain if
+ * @info is %NULL.
+ */
+struct gcov_info *gcov_info_next(struct gcov_info *info)
+{
+	if (!info)
+		return gcov_info_head;
+
+	return info->next;
+}
+
+/**
+ * gcov_info_link - link/add profiling data set to the list
+ * @info: profiling data set
+ */
+void gcov_info_link(struct gcov_info *info)
+{
+	info->next = gcov_info_head;
+	gcov_info_head = info;
+}
+
+/**
+ * gcov_info_unlink - unlink/remove profiling data set from the list
+ * @prev: previous profiling data set
+ * @info: profiling data set
+ */
+void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
+{
+	if (prev)
+		prev->next = info->next;
+	else
+		gcov_info_head = info->next;
+}
+
+/**
+ * gcov_info_within_module - check if a profiling data set belongs to a module
+ * @info: profiling data set
+ * @mod: module
+ *
+ * Returns true if profiling data belongs module, false otherwise.
+ */
+bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
+{
+	return within_module((unsigned long)info, mod);
+}
+
+/* Symbolic links to be created for each profiling data file. */
+const struct gcov_link gcov_link[] = {
+	{ OBJ_TREE, "gcno" },	/* Link to .gcno file in $(objtree). */
+	{ 0, NULL},
+};
+
+/*
+ * Determine whether a counter is active. Doesn't change at run-time.
+ */
+static int counter_active(struct gcov_info *info, unsigned int type)
+{
+	return info->merge[type] ? 1 : 0;
+}
+
+/* Determine number of active counters. Based on gcc magic. */
+static unsigned int num_counter_active(struct gcov_info *info)
+{
+	unsigned int i;
+	unsigned int result = 0;
+
+	for (i = 0; i < GCOV_COUNTERS; i++) {
+		if (counter_active(info, i))
+			result++;
+	}
+	return result;
+}
+
+/**
+ * gcov_info_reset - reset profiling data to zero
+ * @info: profiling data set
+ */
+void gcov_info_reset(struct gcov_info *info)
+{
+	struct gcov_ctr_info *ci_ptr;
+	unsigned int fi_idx;
+	unsigned int ct_idx;
+
+	for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
+		ci_ptr = info->functions[fi_idx]->ctrs;
+
+		for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
+			if (!counter_active(info, ct_idx))
+				continue;
+
+			memset(ci_ptr->values, 0,
+					sizeof(gcov_type) * ci_ptr->num);
+			ci_ptr++;
+		}
+	}
+}
+
+/**
+ * gcov_info_is_compatible - check if profiling data can be added
+ * @info1: first profiling data set
+ * @info2: second profiling data set
+ *
+ * Returns non-zero if profiling data can be added, zero otherwise.
+ */
+int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
+{
+	return (info1->stamp == info2->stamp);
+}
+
+/**
+ * gcov_info_add - add up profiling data
+ * @dst: profiling data set to which data is added
+ * @src: profiling data set which is added
+ *
+ * Adds profiling counts of @src to @dst.
+ */
+void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
+{
+	struct gcov_ctr_info *dci_ptr;
+	struct gcov_ctr_info *sci_ptr;
+	unsigned int fi_idx;
+	unsigned int ct_idx;
+	unsigned int val_idx;
+
+	for (fi_idx = 0; fi_idx < src->n_functions; fi_idx++) {
+		dci_ptr = dst->functions[fi_idx]->ctrs;
+		sci_ptr = src->functions[fi_idx]->ctrs;
+
+		for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
+			if (!counter_active(src, ct_idx))
+				continue;
+
+			for (val_idx = 0; val_idx < sci_ptr->num; val_idx++)
+				dci_ptr->values[val_idx] +=
+					sci_ptr->values[val_idx];
+
+			dci_ptr++;
+			sci_ptr++;
+		}
+	}
+}
+
+/**
+ * gcov_info_dup - duplicate profiling data set
+ * @info: profiling data set to duplicate
+ *
+ * Return newly allocated duplicate on success, %NULL on error.
+ */
+struct gcov_info *gcov_info_dup(struct gcov_info *info)
+{
+	struct gcov_info *dup;
+	struct gcov_ctr_info *dci_ptr; /* dst counter info */
+	struct gcov_ctr_info *sci_ptr; /* src counter info */
+	unsigned int active;
+	unsigned int fi_idx; /* function info idx */
+	unsigned int ct_idx; /* counter type idx */
+	size_t fi_size; /* function info size */
+	size_t cv_size; /* counter values size */
+
+	dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
+	if (!dup)
+		return NULL;
+
+	dup->next = NULL;
+	dup->filename = NULL;
+	dup->functions = NULL;
+
+	dup->filename = kstrdup(info->filename, GFP_KERNEL);
+	if (!dup->filename)
+		goto err_free;
+
+	dup->functions = kcalloc(info->n_functions,
+				 sizeof(struct gcov_fn_info *), GFP_KERNEL);
+	if (!dup->functions)
+		goto err_free;
+
+	active = num_counter_active(info);
+	fi_size = sizeof(struct gcov_fn_info);
+	fi_size += sizeof(struct gcov_ctr_info) * active;
+
+	for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
+		dup->functions[fi_idx] = kzalloc(fi_size, GFP_KERNEL);
+		if (!dup->functions[fi_idx])
+			goto err_free;
+
+		*(dup->functions[fi_idx]) = *(info->functions[fi_idx]);
+
+		sci_ptr = info->functions[fi_idx]->ctrs;
+		dci_ptr = dup->functions[fi_idx]->ctrs;
+
+		for (ct_idx = 0; ct_idx < active; ct_idx++) {
+
+			cv_size = sizeof(gcov_type) * sci_ptr->num;
+
+			dci_ptr->values = kvmalloc(cv_size, GFP_KERNEL);
+
+			if (!dci_ptr->values)
+				goto err_free;
+
+			dci_ptr->num = sci_ptr->num;
+			memcpy(dci_ptr->values, sci_ptr->values, cv_size);
+
+			sci_ptr++;
+			dci_ptr++;
+		}
+	}
+
+	return dup;
+err_free:
+	gcov_info_free(dup);
+	return NULL;
+}
+
+/**
+ * gcov_info_free - release memory for profiling data set duplicate
+ * @info: profiling data set duplicate to free
+ */
+void gcov_info_free(struct gcov_info *info)
+{
+	unsigned int active;
+	unsigned int fi_idx;
+	unsigned int ct_idx;
+	struct gcov_ctr_info *ci_ptr;
+
+	if (!info->functions)
+		goto free_info;
+
+	active = num_counter_active(info);
+
+	for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
+		if (!info->functions[fi_idx])
+			continue;
+
+		ci_ptr = info->functions[fi_idx]->ctrs;
+
+		for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++)
+			kvfree(ci_ptr->values);
+
+		kfree(info->functions[fi_idx]);
+	}
+
+free_info:
+	kfree(info->functions);
+	kfree(info->filename);
+	kfree(info);
+}
+
+/**
+ * convert_to_gcda - convert profiling data set to gcda file format
+ * @buffer: the buffer to store file data or %NULL if no data should be stored
+ * @info: profiling data set to be converted
+ *
+ * Returns the number of bytes that were/would have been stored into the buffer.
+ */
+size_t convert_to_gcda(char *buffer, struct gcov_info *info)
+{
+	struct gcov_fn_info *fi_ptr;
+	struct gcov_ctr_info *ci_ptr;
+	unsigned int fi_idx;
+	unsigned int ct_idx;
+	unsigned int cv_idx;
+	size_t pos = 0;
+
+	/* File header. */
+	pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
+	pos += store_gcov_u32(buffer, pos, info->version);
+	pos += store_gcov_u32(buffer, pos, info->stamp);
+
+#if (__GNUC__ >= 12)
+	/* Use zero as checksum of the compilation unit. */
+	pos += store_gcov_u32(buffer, pos, 0);
+#endif
+
+	for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
+		fi_ptr = info->functions[fi_idx];
+
+		/* Function record. */
+		pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
+		pos += store_gcov_u32(buffer, pos,
+			GCOV_TAG_FUNCTION_LENGTH * GCOV_UNIT_SIZE);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum);
+		pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
+
+		ci_ptr = fi_ptr->ctrs;
+
+		for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
+			if (!counter_active(info, ct_idx))
+				continue;
+
+			/* Counter record. */
+			pos += store_gcov_u32(buffer, pos,
+					      GCOV_TAG_FOR_COUNTER(ct_idx));
+			pos += store_gcov_u32(buffer, pos,
+				ci_ptr->num * 2 * GCOV_UNIT_SIZE);
+
+			for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
+				pos += store_gcov_u64(buffer, pos,
+						      ci_ptr->values[cv_idx]);
+			}
+
+			ci_ptr++;
+		}
+	}
+
+	return pos;
+}
diff --git a/kernel/gcov/gcc_base.c b/kernel/gcov/gcc_base.c
new file mode 100644
index 000000000..3cf736b9f
--- /dev/null
+++ b/kernel/gcov/gcc_base.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include "gcov.h"
+
+/*
+ * __gcov_init is called by gcc-generated constructor code for each object
+ * file compiled with -fprofile-arcs.
+ */
+void __gcov_init(struct gcov_info *info)
+{
+	static unsigned int gcov_version;
+
+	mutex_lock(&gcov_lock);
+	if (gcov_version == 0) {
+		gcov_version = gcov_info_version(info);
+		/*
+		 * Printing gcc's version magic may prove useful for debugging
+		 * incompatibility reports.
+		 */
+		pr_info("version magic: 0x%x\n", gcov_version);
+	}
+	/*
+	 * Add new profiling data structure to list and inform event
+	 * listener.
+	 */
+	gcov_info_link(info);
+	if (gcov_events_enabled)
+		gcov_event(GCOV_ADD, info);
+	mutex_unlock(&gcov_lock);
+}
+EXPORT_SYMBOL(__gcov_init);
+
+/*
+ * These functions may be referenced by gcc-generated profiling code but serve
+ * no function for kernel profiling.
+ */
+void __gcov_flush(void)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_flush);
+
+void __gcov_merge_add(gcov_type *counters, unsigned int n_counters)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_add);
+
+void __gcov_merge_single(gcov_type *counters, unsigned int n_counters)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_single);
+
+void __gcov_merge_delta(gcov_type *counters, unsigned int n_counters)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_delta);
+
+void __gcov_merge_ior(gcov_type *counters, unsigned int n_counters)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_ior);
+
+void __gcov_merge_time_profile(gcov_type *counters, unsigned int n_counters)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_time_profile);
+
+void __gcov_merge_icall_topn(gcov_type *counters, unsigned int n_counters)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_icall_topn);
+
+void __gcov_exit(void)
+{
+	/* Unused. */
+}
+EXPORT_SYMBOL(__gcov_exit);
diff --git a/kernel/gcov/gcov.h b/kernel/gcov/gcov.h
new file mode 100644
index 000000000..912b8ea01
--- /dev/null
+++ b/kernel/gcov/gcov.h
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  Profiling infrastructure declarations.
+ *
+ *  This file is based on gcc-internal definitions. Data structures are
+ *  defined to be compatible with gcc counterparts. For a better
+ *  understanding, refer to gcc source: gcc/gcov-io.h.
+ *
+ *    Copyright IBM Corp. 2009
+ *    Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
+ *
+ *    Uses gcc-internal data definitions.
+ */
+
+#ifndef GCOV_H
+#define GCOV_H GCOV_H
+
+#include <linux/module.h>
+#include <linux/types.h>
+
+/*
+ * Profiling data types used for gcc 3.4 and above - these are defined by
+ * gcc and need to be kept as close to the original definition as possible to
+ * remain compatible.
+ */
+#define GCOV_DATA_MAGIC		((unsigned int) 0x67636461)
+#define GCOV_TAG_FUNCTION	((unsigned int) 0x01000000)
+#define GCOV_TAG_COUNTER_BASE	((unsigned int) 0x01a10000)
+#define GCOV_TAG_FOR_COUNTER(count)					\
+	(GCOV_TAG_COUNTER_BASE + ((unsigned int) (count) << 17))
+
+#if BITS_PER_LONG >= 64
+typedef long gcov_type;
+#else
+typedef long long gcov_type;
+#endif
+
+/* Opaque gcov_info. The gcov structures can change as for example in gcc 4.7 so
+ * we cannot use full definition here and they need to be placed in gcc specific
+ * implementation of gcov. This also means no direct access to the members in
+ * generic code and usage of the interface below.*/
+struct gcov_info;
+
+/* Interface to access gcov_info data  */
+const char *gcov_info_filename(struct gcov_info *info);
+unsigned int gcov_info_version(struct gcov_info *info);
+struct gcov_info *gcov_info_next(struct gcov_info *info);
+void gcov_info_link(struct gcov_info *info);
+void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info);
+bool gcov_info_within_module(struct gcov_info *info, struct module *mod);
+size_t convert_to_gcda(char *buffer, struct gcov_info *info);
+
+/* Base interface. */
+enum gcov_action {
+	GCOV_ADD,
+	GCOV_REMOVE,
+};
+
+void gcov_event(enum gcov_action action, struct gcov_info *info);
+void gcov_enable_events(void);
+
+/* writing helpers */
+size_t store_gcov_u32(void *buffer, size_t off, u32 v);
+size_t store_gcov_u64(void *buffer, size_t off, u64 v);
+
+/* gcov_info control. */
+void gcov_info_reset(struct gcov_info *info);
+int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2);
+void gcov_info_add(struct gcov_info *dest, struct gcov_info *source);
+struct gcov_info *gcov_info_dup(struct gcov_info *info);
+void gcov_info_free(struct gcov_info *info);
+
+struct gcov_link {
+	enum {
+		OBJ_TREE,
+		SRC_TREE,
+	} dir;
+	const char *ext;
+};
+extern const struct gcov_link gcov_link[];
+
+extern int gcov_events_enabled;
+extern struct mutex gcov_lock;
+
+#endif /* GCOV_H */
diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh
new file mode 100755
index 000000000..473036b43
--- /dev/null
+++ b/kernel/gen_kheaders.sh
@@ -0,0 +1,95 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+# This script generates an archive consisting of kernel headers
+# for CONFIG_IKHEADERS.
+set -e
+sfile="$(readlink -f "$0")"
+outdir="$(pwd)"
+tarfile=$1
+cpio_dir=$outdir/$tarfile.tmp
+
+dir_list="
+include/
+arch/$SRCARCH/include/
+"
+
+# Support incremental builds by skipping archive generation
+# if timestamps of files being archived are not changed.
+
+# This block is useful for debugging the incremental builds.
+# Uncomment it for debugging.
+# if [ ! -f /tmp/iter ]; then iter=1; echo 1 > /tmp/iter;
+# else iter=$(($(cat /tmp/iter) + 1)); echo $iter > /tmp/iter; fi
+# find $all_dirs -name "*.h" | xargs ls -l > /tmp/ls-$iter
+
+all_dirs=
+if [ "$building_out_of_srctree" ]; then
+	for d in $dir_list; do
+		all_dirs="$all_dirs $srctree/$d"
+	done
+fi
+all_dirs="$all_dirs $dir_list"
+
+# include/generated/utsversion.h is ignored because it is generated after this
+# script is executed. (utsversion.h is unneeded for kheaders)
+#
+# When Kconfig regenerates include/generated/autoconf.h, its timestamp is
+# updated, but the contents might be still the same. When any CONFIG option is
+# changed, Kconfig touches the corresponding timestamp file include/config/*.
+# Hence, the md5sum detects the configuration change anyway. We do not need to
+# check include/generated/autoconf.h explicitly.
+#
+# Ignore them for md5 calculation to avoid pointless regeneration.
+headers_md5="$(find $all_dirs -name "*.h"			|
+		grep -v "include/generated/utsversion.h"	|
+		grep -v "include/generated/autoconf.h"	|
+		xargs ls -l | md5sum | cut -d ' ' -f1)"
+
+# Any changes to this script will also cause a rebuild of the archive.
+this_file_md5="$(ls -l $sfile | md5sum | cut -d ' ' -f1)"
+if [ -f $tarfile ]; then tarfile_md5="$(md5sum $tarfile | cut -d ' ' -f1)"; fi
+if [ -f kernel/kheaders.md5 ] &&
+	[ "$(head -n 1 kernel/kheaders.md5)" = "$headers_md5" ] &&
+	[ "$(head -n 2 kernel/kheaders.md5 | tail -n 1)" = "$this_file_md5" ] &&
+	[ "$(tail -n 1 kernel/kheaders.md5)" = "$tarfile_md5" ]; then
+		exit
+fi
+
+echo "  GEN     $tarfile"
+
+rm -rf $cpio_dir
+mkdir $cpio_dir
+
+if [ "$building_out_of_srctree" ]; then
+	(
+		cd $srctree
+		for f in $dir_list
+			do find "$f" -name "*.h";
+		done | cpio --quiet -pd $cpio_dir
+	)
+fi
+
+# The second CPIO can complain if files already exist which can happen with out
+# of tree builds having stale headers in srctree. Just silence CPIO for now.
+for f in $dir_list;
+	do find "$f" -name "*.h";
+done | cpio --quiet -pdu $cpio_dir >/dev/null 2>&1
+
+# Remove comments except SDPX lines
+find $cpio_dir -type f -print0 |
+	xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;'
+
+# Create archive and try to normalize metadata for reproducibility.
+# For compatibility with older versions of tar, files are fed to tar
+# pre-sorted, as --sort=name might not be available.
+find $cpio_dir -printf "./%P\n" | LC_ALL=C sort | \
+    tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
+    --owner=0 --group=0 --numeric-owner --no-recursion \
+    -I $XZ -cf $tarfile -C $cpio_dir/ -T - > /dev/null
+
+echo $headers_md5 > kernel/kheaders.md5
+echo "$this_file_md5" >> kernel/kheaders.md5
+echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5
+
+rm -rf $cpio_dir
diff --git a/kernel/groups.c b/kernel/groups.c
new file mode 100644
index 000000000..9aaed2a31
--- /dev/null
+++ b/kernel/groups.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Supplementary group IDs
+ */
+#include <linux/cred.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include <linux/sort.h>
+#include <linux/syscalls.h>
+#include <linux/user_namespace.h>
+#include <linux/vmalloc.h>
+#include <linux/uaccess.h>
+
+struct group_info *groups_alloc(int gidsetsize)
+{
+	struct group_info *gi;
+	gi = kvmalloc(struct_size(gi, gid, gidsetsize), GFP_KERNEL_ACCOUNT);
+	if (!gi)
+		return NULL;
+
+	atomic_set(&gi->usage, 1);
+	gi->ngroups = gidsetsize;
+	return gi;
+}
+
+EXPORT_SYMBOL(groups_alloc);
+
+void groups_free(struct group_info *group_info)
+{
+	kvfree(group_info);
+}
+
+EXPORT_SYMBOL(groups_free);
+
+/* export the group_info to a user-space array */
+static int groups_to_user(gid_t __user *grouplist,
+			  const struct group_info *group_info)
+{
+	struct user_namespace *user_ns = current_user_ns();
+	int i;
+	unsigned int count = group_info->ngroups;
+
+	for (i = 0; i < count; i++) {
+		gid_t gid;
+		gid = from_kgid_munged(user_ns, group_info->gid[i]);
+		if (put_user(gid, grouplist+i))
+			return -EFAULT;
+	}
+	return 0;
+}
+
+/* fill a group_info from a user-space array - it must be allocated already */
+static int groups_from_user(struct group_info *group_info,
+    gid_t __user *grouplist)
+{
+	struct user_namespace *user_ns = current_user_ns();
+	int i;
+	unsigned int count = group_info->ngroups;
+
+	for (i = 0; i < count; i++) {
+		gid_t gid;
+		kgid_t kgid;
+		if (get_user(gid, grouplist+i))
+			return -EFAULT;
+
+		kgid = make_kgid(user_ns, gid);
+		if (!gid_valid(kgid))
+			return -EINVAL;
+
+		group_info->gid[i] = kgid;
+	}
+	return 0;
+}
+
+static int gid_cmp(const void *_a, const void *_b)
+{
+	kgid_t a = *(kgid_t *)_a;
+	kgid_t b = *(kgid_t *)_b;
+
+	return gid_gt(a, b) - gid_lt(a, b);
+}
+
+void groups_sort(struct group_info *group_info)
+{
+	sort(group_info->gid, group_info->ngroups, sizeof(*group_info->gid),
+	     gid_cmp, NULL);
+}
+EXPORT_SYMBOL(groups_sort);
+
+/* a simple bsearch */
+int groups_search(const struct group_info *group_info, kgid_t grp)
+{
+	unsigned int left, right;
+
+	if (!group_info)
+		return 0;
+
+	left = 0;
+	right = group_info->ngroups;
+	while (left < right) {
+		unsigned int mid = (left+right)/2;
+		if (gid_gt(grp, group_info->gid[mid]))
+			left = mid + 1;
+		else if (gid_lt(grp, group_info->gid[mid]))
+			right = mid;
+		else
+			return 1;
+	}
+	return 0;
+}
+
+/**
+ * set_groups - Change a group subscription in a set of credentials
+ * @new: The newly prepared set of credentials to alter
+ * @group_info: The group list to install
+ */
+void set_groups(struct cred *new, struct group_info *group_info)
+{
+	put_group_info(new->group_info);
+	get_group_info(group_info);
+	new->group_info = group_info;
+}
+
+EXPORT_SYMBOL(set_groups);
+
+/**
+ * set_current_groups - Change current's group subscription
+ * @group_info: The group list to impose
+ *
+ * Validate a group subscription and, if valid, impose it upon current's task
+ * security record.
+ */
+int set_current_groups(struct group_info *group_info)
+{
+	struct cred *new;
+	const struct cred *old;
+	int retval;
+
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+
+	old = current_cred();
+
+	set_groups(new, group_info);
+
+	retval = security_task_fix_setgroups(new, old);
+	if (retval < 0)
+		goto error;
+
+	return commit_creds(new);
+
+error:
+	abort_creds(new);
+	return retval;
+}
+
+EXPORT_SYMBOL(set_current_groups);
+
+SYSCALL_DEFINE2(getgroups, int, gidsetsize, gid_t __user *, grouplist)
+{
+	const struct cred *cred = current_cred();
+	int i;
+
+	if (gidsetsize < 0)
+		return -EINVAL;
+
+	/* no need to grab task_lock here; it cannot change */
+	i = cred->group_info->ngroups;
+	if (gidsetsize) {
+		if (i > gidsetsize) {
+			i = -EINVAL;
+			goto out;
+		}
+		if (groups_to_user(grouplist, cred->group_info)) {
+			i = -EFAULT;
+			goto out;
+		}
+	}
+out:
+	return i;
+}
+
+bool may_setgroups(void)
+{
+	struct user_namespace *user_ns = current_user_ns();
+
+	return ns_capable_setid(user_ns, CAP_SETGID) &&
+		userns_may_setgroups(user_ns);
+}
+
+/*
+ *	SMP: Our groups are copy-on-write. We can set them safely
+ *	without another task interfering.
+ */
+
+SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist)
+{
+	struct group_info *group_info;
+	int retval;
+
+	if (!may_setgroups())
+		return -EPERM;
+	if ((unsigned)gidsetsize > NGROUPS_MAX)
+		return -EINVAL;
+
+	group_info = groups_alloc(gidsetsize);
+	if (!group_info)
+		return -ENOMEM;
+	retval = groups_from_user(group_info, grouplist);
+	if (retval) {
+		put_group_info(group_info);
+		return retval;
+	}
+
+	groups_sort(group_info);
+	retval = set_current_groups(group_info);
+	put_group_info(group_info);
+
+	return retval;
+}
+
+/*
+ * Check whether we're fsgid/egid or in the supplemental group..
+ */
+int in_group_p(kgid_t grp)
+{
+	const struct cred *cred = current_cred();
+	int retval = 1;
+
+	if (!gid_eq(grp, cred->fsgid))
+		retval = groups_search(cred->group_info, grp);
+	return retval;
+}
+
+EXPORT_SYMBOL(in_group_p);
+
+int in_egroup_p(kgid_t grp)
+{
+	const struct cred *cred = current_cred();
+	int retval = 1;
+
+	if (!gid_eq(grp, cred->egid))
+		retval = groups_search(cred->group_info, grp);
+	return retval;
+}
+
+EXPORT_SYMBOL(in_egroup_p);
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
new file mode 100644
index 000000000..c71889f3f
--- /dev/null
+++ b/kernel/hung_task.c
@@ -0,0 +1,399 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Detect Hung Task
+ *
+ * kernel/hung_task.c - kernel thread for detecting tasks stuck in D state
+ *
+ */
+
+#include <linux/mm.h>
+#include <linux/cpu.h>
+#include <linux/nmi.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
+#include <linux/lockdep.h>
+#include <linux/export.h>
+#include <linux/panic_notifier.h>
+#include <linux/sysctl.h>
+#include <linux/suspend.h>
+#include <linux/utsname.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/sysctl.h>
+
+#include <trace/events/sched.h>
+
+/*
+ * The number of tasks checked:
+ */
+int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
+
+/*
+ * Limit number of tasks checked in a batch.
+ *
+ * This value controls the preemptibility of khungtaskd since preemption
+ * is disabled during the critical section. It also controls the size of
+ * the RCU grace period. So it needs to be upper-bound.
+ */
+#define HUNG_TASK_LOCK_BREAK (HZ / 10)
+
+/*
+ * Zero means infinite timeout - no checking done:
+ */
+unsigned long __read_mostly sysctl_hung_task_timeout_secs = CONFIG_DEFAULT_HUNG_TASK_TIMEOUT;
+
+/*
+ * Zero (default value) means use sysctl_hung_task_timeout_secs:
+ */
+unsigned long __read_mostly sysctl_hung_task_check_interval_secs;
+
+int __read_mostly sysctl_hung_task_warnings = 10;
+
+static int __read_mostly did_panic;
+static bool hung_task_show_lock;
+static bool hung_task_call_panic;
+static bool hung_task_show_all_bt;
+
+static struct task_struct *watchdog_task;
+
+#ifdef CONFIG_SMP
+/*
+ * Should we dump all CPUs backtraces in a hung task event?
+ * Defaults to 0, can be changed via sysctl.
+ */
+static unsigned int __read_mostly sysctl_hung_task_all_cpu_backtrace;
+#else
+#define sysctl_hung_task_all_cpu_backtrace 0
+#endif /* CONFIG_SMP */
+
+/*
+ * Should we panic (and reboot, if panic_timeout= is set) when a
+ * hung task is detected:
+ */
+unsigned int __read_mostly sysctl_hung_task_panic =
+				IS_ENABLED(CONFIG_BOOTPARAM_HUNG_TASK_PANIC);
+
+static int
+hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr)
+{
+	did_panic = 1;
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block panic_block = {
+	.notifier_call = hung_task_panic,
+};
+
+static void check_hung_task(struct task_struct *t, unsigned long timeout)
+{
+	unsigned long switch_count = t->nvcsw + t->nivcsw;
+
+	/*
+	 * Ensure the task is not frozen.
+	 * Also, skip vfork and any other user process that freezer should skip.
+	 */
+	if (unlikely(READ_ONCE(t->__state) & TASK_FROZEN))
+		return;
+
+	/*
+	 * When a freshly created task is scheduled once, changes its state to
+	 * TASK_UNINTERRUPTIBLE without having ever been switched out once, it
+	 * musn't be checked.
+	 */
+	if (unlikely(!switch_count))
+		return;
+
+	if (switch_count != t->last_switch_count) {
+		t->last_switch_count = switch_count;
+		t->last_switch_time = jiffies;
+		return;
+	}
+	if (time_is_after_jiffies(t->last_switch_time + timeout * HZ))
+		return;
+
+	trace_sched_process_hang(t);
+
+	if (sysctl_hung_task_panic) {
+		console_verbose();
+		hung_task_show_lock = true;
+		hung_task_call_panic = true;
+	}
+
+	/*
+	 * Ok, the task did not get scheduled for more than 2 minutes,
+	 * complain:
+	 */
+	if (sysctl_hung_task_warnings) {
+		if (sysctl_hung_task_warnings > 0)
+			sysctl_hung_task_warnings--;
+		pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n",
+		       t->comm, t->pid, (jiffies - t->last_switch_time) / HZ);
+		pr_err("      %s %s %.*s\n",
+			print_tainted(), init_utsname()->release,
+			(int)strcspn(init_utsname()->version, " "),
+			init_utsname()->version);
+		pr_err("\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
+			" disables this message.\n");
+		sched_show_task(t);
+		hung_task_show_lock = true;
+
+		if (sysctl_hung_task_all_cpu_backtrace)
+			hung_task_show_all_bt = true;
+	}
+
+	touch_nmi_watchdog();
+}
+
+/*
+ * To avoid extending the RCU grace period for an unbounded amount of time,
+ * periodically exit the critical section and enter a new one.
+ *
+ * For preemptible RCU it is sufficient to call rcu_read_unlock in order
+ * to exit the grace period. For classic RCU, a reschedule is required.
+ */
+static bool rcu_lock_break(struct task_struct *g, struct task_struct *t)
+{
+	bool can_cont;
+
+	get_task_struct(g);
+	get_task_struct(t);
+	rcu_read_unlock();
+	cond_resched();
+	rcu_read_lock();
+	can_cont = pid_alive(g) && pid_alive(t);
+	put_task_struct(t);
+	put_task_struct(g);
+
+	return can_cont;
+}
+
+/*
+ * Check whether a TASK_UNINTERRUPTIBLE does not get woken up for
+ * a really long time (120 seconds). If that happens, print out
+ * a warning.
+ */
+static void check_hung_uninterruptible_tasks(unsigned long timeout)
+{
+	int max_count = sysctl_hung_task_check_count;
+	unsigned long last_break = jiffies;
+	struct task_struct *g, *t;
+
+	/*
+	 * If the system crashed already then all bets are off,
+	 * do not report extra hung tasks:
+	 */
+	if (test_taint(TAINT_DIE) || did_panic)
+		return;
+
+	hung_task_show_lock = false;
+	rcu_read_lock();
+	for_each_process_thread(g, t) {
+		unsigned int state;
+
+		if (!max_count--)
+			goto unlock;
+		if (time_after(jiffies, last_break + HUNG_TASK_LOCK_BREAK)) {
+			if (!rcu_lock_break(g, t))
+				goto unlock;
+			last_break = jiffies;
+		}
+		/*
+		 * skip the TASK_KILLABLE tasks -- these can be killed
+		 * skip the TASK_IDLE tasks -- those are genuinely idle
+		 */
+		state = READ_ONCE(t->__state);
+		if ((state & TASK_UNINTERRUPTIBLE) &&
+		    !(state & TASK_WAKEKILL) &&
+		    !(state & TASK_NOLOAD))
+			check_hung_task(t, timeout);
+	}
+ unlock:
+	rcu_read_unlock();
+	if (hung_task_show_lock)
+		debug_show_all_locks();
+
+	if (hung_task_show_all_bt) {
+		hung_task_show_all_bt = false;
+		trigger_all_cpu_backtrace();
+	}
+
+	if (hung_task_call_panic)
+		panic("hung_task: blocked tasks");
+}
+
+static long hung_timeout_jiffies(unsigned long last_checked,
+				 unsigned long timeout)
+{
+	/* timeout of 0 will disable the watchdog */
+	return timeout ? last_checked - jiffies + timeout * HZ :
+		MAX_SCHEDULE_TIMEOUT;
+}
+
+#ifdef CONFIG_SYSCTL
+/*
+ * Process updating of timeout sysctl
+ */
+static int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
+				  void *buffer,
+				  size_t *lenp, loff_t *ppos)
+{
+	int ret;
+
+	ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
+
+	if (ret || !write)
+		goto out;
+
+	wake_up_process(watchdog_task);
+
+ out:
+	return ret;
+}
+
+/*
+ * This is needed for proc_doulongvec_minmax of sysctl_hung_task_timeout_secs
+ * and hung_task_check_interval_secs
+ */
+static const unsigned long hung_task_timeout_max = (LONG_MAX / HZ);
+static struct ctl_table hung_task_sysctls[] = {
+#ifdef CONFIG_SMP
+	{
+		.procname	= "hung_task_all_cpu_backtrace",
+		.data		= &sysctl_hung_task_all_cpu_backtrace,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#endif /* CONFIG_SMP */
+	{
+		.procname	= "hung_task_panic",
+		.data		= &sysctl_hung_task_panic,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "hung_task_check_count",
+		.data		= &sysctl_hung_task_check_count,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+	{
+		.procname	= "hung_task_timeout_secs",
+		.data		= &sysctl_hung_task_timeout_secs,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= proc_dohung_task_timeout_secs,
+		.extra2		= (void *)&hung_task_timeout_max,
+	},
+	{
+		.procname	= "hung_task_check_interval_secs",
+		.data		= &sysctl_hung_task_check_interval_secs,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= proc_dohung_task_timeout_secs,
+		.extra2		= (void *)&hung_task_timeout_max,
+	},
+	{
+		.procname	= "hung_task_warnings",
+		.data		= &sysctl_hung_task_warnings,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_NEG_ONE,
+	},
+	{}
+};
+
+static void __init hung_task_sysctl_init(void)
+{
+	register_sysctl_init("kernel", hung_task_sysctls);
+}
+#else
+#define hung_task_sysctl_init() do { } while (0)
+#endif /* CONFIG_SYSCTL */
+
+
+static atomic_t reset_hung_task = ATOMIC_INIT(0);
+
+void reset_hung_task_detector(void)
+{
+	atomic_set(&reset_hung_task, 1);
+}
+EXPORT_SYMBOL_GPL(reset_hung_task_detector);
+
+static bool hung_detector_suspended;
+
+static int hungtask_pm_notify(struct notifier_block *self,
+			      unsigned long action, void *hcpu)
+{
+	switch (action) {
+	case PM_SUSPEND_PREPARE:
+	case PM_HIBERNATION_PREPARE:
+	case PM_RESTORE_PREPARE:
+		hung_detector_suspended = true;
+		break;
+	case PM_POST_SUSPEND:
+	case PM_POST_HIBERNATION:
+	case PM_POST_RESTORE:
+		hung_detector_suspended = false;
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+/*
+ * kthread which checks for tasks stuck in D state
+ */
+static int watchdog(void *dummy)
+{
+	unsigned long hung_last_checked = jiffies;
+
+	set_user_nice(current, 0);
+
+	for ( ; ; ) {
+		unsigned long timeout = sysctl_hung_task_timeout_secs;
+		unsigned long interval = sysctl_hung_task_check_interval_secs;
+		long t;
+
+		if (interval == 0)
+			interval = timeout;
+		interval = min_t(unsigned long, interval, timeout);
+		t = hung_timeout_jiffies(hung_last_checked, interval);
+		if (t <= 0) {
+			if (!atomic_xchg(&reset_hung_task, 0) &&
+			    !hung_detector_suspended)
+				check_hung_uninterruptible_tasks(timeout);
+			hung_last_checked = jiffies;
+			continue;
+		}
+		schedule_timeout_interruptible(t);
+	}
+
+	return 0;
+}
+
+static int __init hung_task_init(void)
+{
+	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
+
+	/* Disable hung task detector on suspend */
+	pm_notifier(hungtask_pm_notify, 0);
+
+	watchdog_task = kthread_run(watchdog, NULL, "khungtaskd");
+	hung_task_sysctl_init();
+
+	return 0;
+}
+subsys_initcall(hung_task_init);
diff --git a/kernel/iomem.c b/kernel/iomem.c
new file mode 100644
index 000000000..62c92e43a
--- /dev/null
+++ b/kernel/iomem.c
@@ -0,0 +1,167 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/io.h>
+#include <linux/mm.h>
+
+#ifndef ioremap_cache
+/* temporary while we convert existing ioremap_cache users to memremap */
+__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
+{
+	return ioremap(offset, size);
+}
+#endif
+
+#ifndef arch_memremap_wb
+static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
+{
+	return (__force void *)ioremap_cache(offset, size);
+}
+#endif
+
+#ifndef arch_memremap_can_ram_remap
+static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
+					unsigned long flags)
+{
+	return true;
+}
+#endif
+
+static void *try_ram_remap(resource_size_t offset, size_t size,
+			   unsigned long flags)
+{
+	unsigned long pfn = PHYS_PFN(offset);
+
+	/* In the simple case just return the existing linear address */
+	if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) &&
+	    arch_memremap_can_ram_remap(offset, size, flags))
+		return __va(offset);
+
+	return NULL; /* fallback to arch_memremap_wb */
+}
+
+/**
+ * memremap() - remap an iomem_resource as cacheable memory
+ * @offset: iomem resource start address
+ * @size: size of remap
+ * @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC,
+ *		  MEMREMAP_ENC, MEMREMAP_DEC
+ *
+ * memremap() is "ioremap" for cases where it is known that the resource
+ * being mapped does not have i/o side effects and the __iomem
+ * annotation is not applicable. In the case of multiple flags, the different
+ * mapping types will be attempted in the order listed below until one of
+ * them succeeds.
+ *
+ * MEMREMAP_WB - matches the default mapping for System RAM on
+ * the architecture.  This is usually a read-allocate write-back cache.
+ * Moreover, if MEMREMAP_WB is specified and the requested remap region is RAM
+ * memremap() will bypass establishing a new mapping and instead return
+ * a pointer into the direct map.
+ *
+ * MEMREMAP_WT - establish a mapping whereby writes either bypass the
+ * cache or are written through to memory and never exist in a
+ * cache-dirty state with respect to program visibility.  Attempts to
+ * map System RAM with this mapping type will fail.
+ *
+ * MEMREMAP_WC - establish a writecombine mapping, whereby writes may
+ * be coalesced together (e.g. in the CPU's write buffers), but is otherwise
+ * uncached. Attempts to map System RAM with this mapping type will fail.
+ */
+void *memremap(resource_size_t offset, size_t size, unsigned long flags)
+{
+	int is_ram = region_intersects(offset, size,
+				       IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
+	void *addr = NULL;
+
+	if (!flags)
+		return NULL;
+
+	if (is_ram == REGION_MIXED) {
+		WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
+				&offset, (unsigned long) size);
+		return NULL;
+	}
+
+	/* Try all mapping types requested until one returns non-NULL */
+	if (flags & MEMREMAP_WB) {
+		/*
+		 * MEMREMAP_WB is special in that it can be satisfied
+		 * from the direct map.  Some archs depend on the
+		 * capability of memremap() to autodetect cases where
+		 * the requested range is potentially in System RAM.
+		 */
+		if (is_ram == REGION_INTERSECTS)
+			addr = try_ram_remap(offset, size, flags);
+		if (!addr)
+			addr = arch_memremap_wb(offset, size);
+	}
+
+	/*
+	 * If we don't have a mapping yet and other request flags are
+	 * present then we will be attempting to establish a new virtual
+	 * address mapping.  Enforce that this mapping is not aliasing
+	 * System RAM.
+	 */
+	if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {
+		WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
+				&offset, (unsigned long) size);
+		return NULL;
+	}
+
+	if (!addr && (flags & MEMREMAP_WT))
+		addr = ioremap_wt(offset, size);
+
+	if (!addr && (flags & MEMREMAP_WC))
+		addr = ioremap_wc(offset, size);
+
+	return addr;
+}
+EXPORT_SYMBOL(memremap);
+
+void memunmap(void *addr)
+{
+	if (is_ioremap_addr(addr))
+		iounmap((void __iomem *) addr);
+}
+EXPORT_SYMBOL(memunmap);
+
+static void devm_memremap_release(struct device *dev, void *res)
+{
+	memunmap(*(void **)res);
+}
+
+static int devm_memremap_match(struct device *dev, void *res, void *match_data)
+{
+	return *(void **)res == match_data;
+}
+
+void *devm_memremap(struct device *dev, resource_size_t offset,
+		size_t size, unsigned long flags)
+{
+	void **ptr, *addr;
+
+	ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,
+			dev_to_node(dev));
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	addr = memremap(offset, size, flags);
+	if (addr) {
+		*ptr = addr;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+		return ERR_PTR(-ENXIO);
+	}
+
+	return addr;
+}
+EXPORT_SYMBOL(devm_memremap);
+
+void devm_memunmap(struct device *dev, void *addr)
+{
+	WARN_ON(devres_release(dev, devm_memremap_release,
+				devm_memremap_match, addr));
+}
+EXPORT_SYMBOL(devm_memunmap);
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
new file mode 100644
index 000000000..db3d174c5
--- /dev/null
+++ b/kernel/irq/Kconfig
@@ -0,0 +1,152 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "IRQ subsystem"
+# Options selectable by the architecture code
+
+# Make sparse irq Kconfig switch below available
+config MAY_HAVE_SPARSE_IRQ
+       bool
+
+# Legacy support, required for itanic
+config GENERIC_IRQ_LEGACY
+       bool
+
+# Enable the generic irq autoprobe mechanism
+config GENERIC_IRQ_PROBE
+	bool
+
+# Use the generic /proc/interrupts implementation
+config GENERIC_IRQ_SHOW
+       bool
+
+# Print level/edge extra information
+config GENERIC_IRQ_SHOW_LEVEL
+       bool
+
+# Supports effective affinity mask
+config GENERIC_IRQ_EFFECTIVE_AFF_MASK
+       depends on SMP
+       bool
+
+# Support for delayed migration from interrupt context
+config GENERIC_PENDING_IRQ
+	bool
+
+# Support for generic irq migrating off cpu before the cpu is offline.
+config GENERIC_IRQ_MIGRATION
+	bool
+
+# Alpha specific irq affinity mechanism
+config AUTO_IRQ_AFFINITY
+       bool
+
+# Interrupt injection mechanism
+config GENERIC_IRQ_INJECTION
+	bool
+
+# Tasklet based software resend for pending interrupts on enable_irq()
+config HARDIRQS_SW_RESEND
+       bool
+
+# Edge style eoi based handler (cell)
+config IRQ_EDGE_EOI_HANDLER
+       bool
+
+# Generic configurable interrupt chip implementation
+config GENERIC_IRQ_CHIP
+       bool
+       select IRQ_DOMAIN
+
+# Generic irq_domain hw <--> linux irq number translation
+config IRQ_DOMAIN
+	bool
+
+# Support for simulated interrupts
+config IRQ_SIM
+	bool
+	select IRQ_WORK
+	select IRQ_DOMAIN
+
+# Support for hierarchical irq domains
+config IRQ_DOMAIN_HIERARCHY
+	bool
+	select IRQ_DOMAIN
+
+# Support for obsolete non-mapping irq domains
+config IRQ_DOMAIN_NOMAP
+	bool
+	select IRQ_DOMAIN
+
+# Support for hierarchical fasteoi+edge and fasteoi+level handlers
+config IRQ_FASTEOI_HIERARCHY_HANDLERS
+	bool
+
+# Generic IRQ IPI support
+config GENERIC_IRQ_IPI
+	bool
+	depends on SMP
+	select IRQ_DOMAIN_HIERARCHY
+
+# Generic MSI interrupt support
+config GENERIC_MSI_IRQ
+	bool
+
+# Generic MSI hierarchical interrupt domain support
+config GENERIC_MSI_IRQ_DOMAIN
+	bool
+	select IRQ_DOMAIN_HIERARCHY
+	select GENERIC_MSI_IRQ
+
+config IRQ_MSI_IOMMU
+	bool
+
+config IRQ_TIMINGS
+	bool
+
+config GENERIC_IRQ_MATRIX_ALLOCATOR
+	bool
+
+config GENERIC_IRQ_RESERVATION_MODE
+	bool
+
+# Support forced irq threading
+config IRQ_FORCED_THREADING
+       bool
+
+config SPARSE_IRQ
+	bool "Support sparse irq numbering" if MAY_HAVE_SPARSE_IRQ
+	help
+
+	  Sparse irq numbering is useful for distro kernels that want
+	  to define a high CONFIG_NR_CPUS value but still want to have
+	  low kernel memory footprint on smaller machines.
+
+	  ( Sparse irqs can also be beneficial on NUMA boxes, as they spread
+	    out the interrupt descriptors in a more NUMA-friendly way. )
+
+	  If you don't know what to do here, say N.
+
+config GENERIC_IRQ_DEBUGFS
+	bool "Expose irq internals in debugfs"
+	depends on DEBUG_FS
+	select GENERIC_IRQ_INJECTION
+	default n
+	help
+
+	  Exposes internal state information through debugfs. Mostly for
+	  developers and debugging of hard to diagnose interrupt problems.
+
+	  If you don't know what to do here, say N.
+
+endmenu
+
+config GENERIC_IRQ_MULTI_HANDLER
+	bool
+	help
+	  Allow to specify the low level IRQ handler at run time.
+
+# Cavium Octeon is the last system to use this deprecated option
+# Do not even think of enabling this on any new platform
+config DEPRECATED_IRQ_CPU_ONOFFLINE
+	bool
+	depends on CAVIUM_OCTEON_SOC
+	default CAVIUM_OCTEON_SOC
diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
new file mode 100644
index 000000000..b4f53717d
--- /dev/null
+++ b/kernel/irq/Makefile
@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-y := irqdesc.o handle.o manage.o spurious.o resend.o chip.o dummychip.o devres.o
+obj-$(CONFIG_IRQ_TIMINGS) += timings.o
+ifeq ($(CONFIG_TEST_IRQ_TIMINGS),y)
+	CFLAGS_timings.o += -DDEBUG
+endif
+obj-$(CONFIG_GENERIC_IRQ_CHIP) += generic-chip.o
+obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o
+obj-$(CONFIG_IRQ_DOMAIN) += irqdomain.o
+obj-$(CONFIG_IRQ_SIM) += irq_sim.o
+obj-$(CONFIG_PROC_FS) += proc.o
+obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o
+obj-$(CONFIG_GENERIC_IRQ_MIGRATION) += cpuhotplug.o
+obj-$(CONFIG_PM_SLEEP) += pm.o
+obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o
+obj-$(CONFIG_GENERIC_IRQ_IPI) += ipi.o
+obj-$(CONFIG_SMP) += affinity.o
+obj-$(CONFIG_GENERIC_IRQ_DEBUGFS) += debugfs.o
+obj-$(CONFIG_GENERIC_IRQ_MATRIX_ALLOCATOR) += matrix.o
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
new file mode 100644
index 000000000..44a4eba80
--- /dev/null
+++ b/kernel/irq/affinity.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2016 Thomas Gleixner.
+ * Copyright (C) 2016-2017 Christoph Hellwig.
+ */
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/cpu.h>
+#include <linux/group_cpus.h>
+
+static void default_calc_sets(struct irq_affinity *affd, unsigned int affvecs)
+{
+	affd->nr_sets = 1;
+	affd->set_size[0] = affvecs;
+}
+
+/**
+ * irq_create_affinity_masks - Create affinity masks for multiqueue spreading
+ * @nvecs:	The total number of vectors
+ * @affd:	Description of the affinity requirements
+ *
+ * Returns the irq_affinity_desc pointer or NULL if allocation failed.
+ */
+struct irq_affinity_desc *
+irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
+{
+	unsigned int affvecs, curvec, usedvecs, i;
+	struct irq_affinity_desc *masks = NULL;
+
+	/*
+	 * Determine the number of vectors which need interrupt affinities
+	 * assigned. If the pre/post request exhausts the available vectors
+	 * then nothing to do here except for invoking the calc_sets()
+	 * callback so the device driver can adjust to the situation.
+	 */
+	if (nvecs > affd->pre_vectors + affd->post_vectors)
+		affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
+	else
+		affvecs = 0;
+
+	/*
+	 * Simple invocations do not provide a calc_sets() callback. Install
+	 * the generic one.
+	 */
+	if (!affd->calc_sets)
+		affd->calc_sets = default_calc_sets;
+
+	/* Recalculate the sets */
+	affd->calc_sets(affd, affvecs);
+
+	if (WARN_ON_ONCE(affd->nr_sets > IRQ_AFFINITY_MAX_SETS))
+		return NULL;
+
+	/* Nothing to assign? */
+	if (!affvecs)
+		return NULL;
+
+	masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
+	if (!masks)
+		return NULL;
+
+	/* Fill out vectors at the beginning that don't need affinity */
+	for (curvec = 0; curvec < affd->pre_vectors; curvec++)
+		cpumask_copy(&masks[curvec].mask, irq_default_affinity);
+
+	/*
+	 * Spread on present CPUs starting from affd->pre_vectors. If we
+	 * have multiple sets, build each sets affinity mask separately.
+	 */
+	for (i = 0, usedvecs = 0; i < affd->nr_sets; i++) {
+		unsigned int this_vecs = affd->set_size[i];
+		int j;
+		struct cpumask *result = group_cpus_evenly(this_vecs);
+
+		if (!result) {
+			kfree(masks);
+			return NULL;
+		}
+
+		for (j = 0; j < this_vecs; j++)
+			cpumask_copy(&masks[curvec + j].mask, &result[j]);
+		kfree(result);
+
+		curvec += this_vecs;
+		usedvecs += this_vecs;
+	}
+
+	/* Fill out vectors at the end that don't need affinity */
+	if (usedvecs >= affvecs)
+		curvec = affd->pre_vectors + affvecs;
+	else
+		curvec = affd->pre_vectors + usedvecs;
+	for (; curvec < nvecs; curvec++)
+		cpumask_copy(&masks[curvec].mask, irq_default_affinity);
+
+	/* Mark the managed interrupts */
+	for (i = affd->pre_vectors; i < nvecs - affd->post_vectors; i++)
+		masks[i].is_managed = 1;
+
+	return masks;
+}
+
+/**
+ * irq_calc_affinity_vectors - Calculate the optimal number of vectors
+ * @minvec:	The minimum number of vectors available
+ * @maxvec:	The maximum number of vectors available
+ * @affd:	Description of the affinity requirements
+ */
+unsigned int irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec,
+				       const struct irq_affinity *affd)
+{
+	unsigned int resv = affd->pre_vectors + affd->post_vectors;
+	unsigned int set_vecs;
+
+	if (resv > minvec)
+		return 0;
+
+	if (affd->calc_sets) {
+		set_vecs = maxvec - resv;
+	} else {
+		cpus_read_lock();
+		set_vecs = cpumask_weight(cpu_possible_mask);
+		cpus_read_unlock();
+	}
+
+	return resv + min(set_vecs, maxvec - resv);
+}
diff --git a/kernel/irq/autoprobe.c b/kernel/irq/autoprobe.c
new file mode 100644
index 000000000..ae60cae24
--- /dev/null
+++ b/kernel/irq/autoprobe.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
+ *
+ * This file contains the interrupt probing code and driver APIs.
+ */
+
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/async.h>
+
+#include "internals.h"
+
+/*
+ * Autodetection depends on the fact that any interrupt that
+ * comes in on to an unassigned handler will get stuck with
+ * "IRQS_WAITING" cleared and the interrupt disabled.
+ */
+static DEFINE_MUTEX(probing_active);
+
+/**
+ *	probe_irq_on	- begin an interrupt autodetect
+ *
+ *	Commence probing for an interrupt. The interrupts are scanned
+ *	and a mask of potential interrupt lines is returned.
+ *
+ */
+unsigned long probe_irq_on(void)
+{
+	struct irq_desc *desc;
+	unsigned long mask = 0;
+	int i;
+
+	/*
+	 * quiesce the kernel, or at least the asynchronous portion
+	 */
+	async_synchronize_full();
+	mutex_lock(&probing_active);
+	/*
+	 * something may have generated an irq long ago and we want to
+	 * flush such a longstanding irq before considering it as spurious.
+	 */
+	for_each_irq_desc_reverse(i, desc) {
+		raw_spin_lock_irq(&desc->lock);
+		if (!desc->action && irq_settings_can_probe(desc)) {
+			/*
+			 * Some chips need to know about probing in
+			 * progress:
+			 */
+			if (desc->irq_data.chip->irq_set_type)
+				desc->irq_data.chip->irq_set_type(&desc->irq_data,
+							 IRQ_TYPE_PROBE);
+			irq_activate_and_startup(desc, IRQ_NORESEND);
+		}
+		raw_spin_unlock_irq(&desc->lock);
+	}
+
+	/* Wait for longstanding interrupts to trigger. */
+	msleep(20);
+
+	/*
+	 * enable any unassigned irqs
+	 * (we must startup again here because if a longstanding irq
+	 * happened in the previous stage, it may have masked itself)
+	 */
+	for_each_irq_desc_reverse(i, desc) {
+		raw_spin_lock_irq(&desc->lock);
+		if (!desc->action && irq_settings_can_probe(desc)) {
+			desc->istate |= IRQS_AUTODETECT | IRQS_WAITING;
+			if (irq_activate_and_startup(desc, IRQ_NORESEND))
+				desc->istate |= IRQS_PENDING;
+		}
+		raw_spin_unlock_irq(&desc->lock);
+	}
+
+	/*
+	 * Wait for spurious interrupts to trigger
+	 */
+	msleep(100);
+
+	/*
+	 * Now filter out any obviously spurious interrupts
+	 */
+	for_each_irq_desc(i, desc) {
+		raw_spin_lock_irq(&desc->lock);
+
+		if (desc->istate & IRQS_AUTODETECT) {
+			/* It triggered already - consider it spurious. */
+			if (!(desc->istate & IRQS_WAITING)) {
+				desc->istate &= ~IRQS_AUTODETECT;
+				irq_shutdown_and_deactivate(desc);
+			} else
+				if (i < 32)
+					mask |= 1 << i;
+		}
+		raw_spin_unlock_irq(&desc->lock);
+	}
+
+	return mask;
+}
+EXPORT_SYMBOL(probe_irq_on);
+
+/**
+ *	probe_irq_mask - scan a bitmap of interrupt lines
+ *	@val:	mask of interrupts to consider
+ *
+ *	Scan the interrupt lines and return a bitmap of active
+ *	autodetect interrupts. The interrupt probe logic state
+ *	is then returned to its previous value.
+ *
+ *	Note: we need to scan all the irq's even though we will
+ *	only return autodetect irq numbers - just so that we reset
+ *	them all to a known state.
+ */
+unsigned int probe_irq_mask(unsigned long val)
+{
+	unsigned int mask = 0;
+	struct irq_desc *desc;
+	int i;
+
+	for_each_irq_desc(i, desc) {
+		raw_spin_lock_irq(&desc->lock);
+		if (desc->istate & IRQS_AUTODETECT) {
+			if (i < 16 && !(desc->istate & IRQS_WAITING))
+				mask |= 1 << i;
+
+			desc->istate &= ~IRQS_AUTODETECT;
+			irq_shutdown_and_deactivate(desc);
+		}
+		raw_spin_unlock_irq(&desc->lock);
+	}
+	mutex_unlock(&probing_active);
+
+	return mask & val;
+}
+EXPORT_SYMBOL(probe_irq_mask);
+
+/**
+ *	probe_irq_off	- end an interrupt autodetect
+ *	@val: mask of potential interrupts (unused)
+ *
+ *	Scans the unused interrupt lines and returns the line which
+ *	appears to have triggered the interrupt. If no interrupt was
+ *	found then zero is returned. If more than one interrupt is
+ *	found then minus the first candidate is returned to indicate
+ *	their is doubt.
+ *
+ *	The interrupt probe logic state is returned to its previous
+ *	value.
+ *
+ *	BUGS: When used in a module (which arguably shouldn't happen)
+ *	nothing prevents two IRQ probe callers from overlapping. The
+ *	results of this are non-optimal.
+ */
+int probe_irq_off(unsigned long val)
+{
+	int i, irq_found = 0, nr_of_irqs = 0;
+	struct irq_desc *desc;
+
+	for_each_irq_desc(i, desc) {
+		raw_spin_lock_irq(&desc->lock);
+
+		if (desc->istate & IRQS_AUTODETECT) {
+			if (!(desc->istate & IRQS_WAITING)) {
+				if (!nr_of_irqs)
+					irq_found = i;
+				nr_of_irqs++;
+			}
+			desc->istate &= ~IRQS_AUTODETECT;
+			irq_shutdown_and_deactivate(desc);
+		}
+		raw_spin_unlock_irq(&desc->lock);
+	}
+	mutex_unlock(&probing_active);
+
+	if (nr_of_irqs > 1)
+		irq_found = -irq_found;
+
+	return irq_found;
+}
+EXPORT_SYMBOL(probe_irq_off);
+
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
new file mode 100644
index 000000000..8ac37e8e7
--- /dev/null
+++ b/kernel/irq/chip.c
@@ -0,0 +1,1607 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
+ * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
+ *
+ * This file contains the core interrupt handling code, for irq-chip based
+ * architectures. Detailed information is available in
+ * Documentation/core-api/genericirq.rst
+ */
+
+#include <linux/irq.h>
+#include <linux/msi.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+#include <linux/irqdomain.h>
+
+#include <trace/events/irq.h>
+
+#include "internals.h"
+
+static irqreturn_t bad_chained_irq(int irq, void *dev_id)
+{
+	WARN_ONCE(1, "Chained irq %d should not call an action\n", irq);
+	return IRQ_NONE;
+}
+
+/*
+ * Chained handlers should never call action on their IRQ. This default
+ * action will emit warning if such thing happens.
+ */
+struct irqaction chained_action = {
+	.handler = bad_chained_irq,
+};
+
+/**
+ *	irq_set_chip - set the irq chip for an irq
+ *	@irq:	irq number
+ *	@chip:	pointer to irq chip description structure
+ */
+int irq_set_chip(unsigned int irq, const struct irq_chip *chip)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+
+	if (!desc)
+		return -EINVAL;
+
+	desc->irq_data.chip = (struct irq_chip *)(chip ?: &no_irq_chip);
+	irq_put_desc_unlock(desc, flags);
+	/*
+	 * For !CONFIG_SPARSE_IRQ make the irq show up in
+	 * allocated_irqs.
+	 */
+	irq_mark_irq(irq);
+	return 0;
+}
+EXPORT_SYMBOL(irq_set_chip);
+
+/**
+ *	irq_set_irq_type - set the irq trigger type for an irq
+ *	@irq:	irq number
+ *	@type:	IRQ_TYPE_{LEVEL,EDGE}_* value - see include/linux/irq.h
+ */
+int irq_set_irq_type(unsigned int irq, unsigned int type)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
+	int ret = 0;
+
+	if (!desc)
+		return -EINVAL;
+
+	ret = __irq_set_trigger(desc, type);
+	irq_put_desc_busunlock(desc, flags);
+	return ret;
+}
+EXPORT_SYMBOL(irq_set_irq_type);
+
+/**
+ *	irq_set_handler_data - set irq handler data for an irq
+ *	@irq:	Interrupt number
+ *	@data:	Pointer to interrupt specific data
+ *
+ *	Set the hardware irq controller data for an irq
+ */
+int irq_set_handler_data(unsigned int irq, void *data)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+
+	if (!desc)
+		return -EINVAL;
+	desc->irq_common_data.handler_data = data;
+	irq_put_desc_unlock(desc, flags);
+	return 0;
+}
+EXPORT_SYMBOL(irq_set_handler_data);
+
+/**
+ *	irq_set_msi_desc_off - set MSI descriptor data for an irq at offset
+ *	@irq_base:	Interrupt number base
+ *	@irq_offset:	Interrupt number offset
+ *	@entry:		Pointer to MSI descriptor data
+ *
+ *	Set the MSI descriptor entry for an irq at offset
+ */
+int irq_set_msi_desc_off(unsigned int irq_base, unsigned int irq_offset,
+			 struct msi_desc *entry)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_lock(irq_base + irq_offset, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
+
+	if (!desc)
+		return -EINVAL;
+	desc->irq_common_data.msi_desc = entry;
+	if (entry && !irq_offset)
+		entry->irq = irq_base;
+	irq_put_desc_unlock(desc, flags);
+	return 0;
+}
+
+/**
+ *	irq_set_msi_desc - set MSI descriptor data for an irq
+ *	@irq:	Interrupt number
+ *	@entry:	Pointer to MSI descriptor data
+ *
+ *	Set the MSI descriptor entry for an irq
+ */
+int irq_set_msi_desc(unsigned int irq, struct msi_desc *entry)
+{
+	return irq_set_msi_desc_off(irq, 0, entry);
+}
+
+/**
+ *	irq_set_chip_data - set irq chip data for an irq
+ *	@irq:	Interrupt number
+ *	@data:	Pointer to chip specific data
+ *
+ *	Set the hardware irq chip data for an irq
+ */
+int irq_set_chip_data(unsigned int irq, void *data)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+
+	if (!desc)
+		return -EINVAL;
+	desc->irq_data.chip_data = data;
+	irq_put_desc_unlock(desc, flags);
+	return 0;
+}
+EXPORT_SYMBOL(irq_set_chip_data);
+
+struct irq_data *irq_get_irq_data(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	return desc ? &desc->irq_data : NULL;
+}
+EXPORT_SYMBOL_GPL(irq_get_irq_data);
+
+static void irq_state_clr_disabled(struct irq_desc *desc)
+{
+	irqd_clear(&desc->irq_data, IRQD_IRQ_DISABLED);
+}
+
+static void irq_state_clr_masked(struct irq_desc *desc)
+{
+	irqd_clear(&desc->irq_data, IRQD_IRQ_MASKED);
+}
+
+static void irq_state_clr_started(struct irq_desc *desc)
+{
+	irqd_clear(&desc->irq_data, IRQD_IRQ_STARTED);
+}
+
+static void irq_state_set_started(struct irq_desc *desc)
+{
+	irqd_set(&desc->irq_data, IRQD_IRQ_STARTED);
+}
+
+enum {
+	IRQ_STARTUP_NORMAL,
+	IRQ_STARTUP_MANAGED,
+	IRQ_STARTUP_ABORT,
+};
+
+#ifdef CONFIG_SMP
+static int
+__irq_startup_managed(struct irq_desc *desc, const struct cpumask *aff,
+		      bool force)
+{
+	struct irq_data *d = irq_desc_get_irq_data(desc);
+
+	if (!irqd_affinity_is_managed(d))
+		return IRQ_STARTUP_NORMAL;
+
+	irqd_clr_managed_shutdown(d);
+
+	if (cpumask_any_and(aff, cpu_online_mask) >= nr_cpu_ids) {
+		/*
+		 * Catch code which fiddles with enable_irq() on a managed
+		 * and potentially shutdown IRQ. Chained interrupt
+		 * installment or irq auto probing should not happen on
+		 * managed irqs either.
+		 */
+		if (WARN_ON_ONCE(force))
+			return IRQ_STARTUP_ABORT;
+		/*
+		 * The interrupt was requested, but there is no online CPU
+		 * in it's affinity mask. Put it into managed shutdown
+		 * state and let the cpu hotplug mechanism start it up once
+		 * a CPU in the mask becomes available.
+		 */
+		return IRQ_STARTUP_ABORT;
+	}
+	/*
+	 * Managed interrupts have reserved resources, so this should not
+	 * happen.
+	 */
+	if (WARN_ON(irq_domain_activate_irq(d, false)))
+		return IRQ_STARTUP_ABORT;
+	return IRQ_STARTUP_MANAGED;
+}
+#else
+static __always_inline int
+__irq_startup_managed(struct irq_desc *desc, const struct cpumask *aff,
+		      bool force)
+{
+	return IRQ_STARTUP_NORMAL;
+}
+#endif
+
+static int __irq_startup(struct irq_desc *desc)
+{
+	struct irq_data *d = irq_desc_get_irq_data(desc);
+	int ret = 0;
+
+	/* Warn if this interrupt is not activated but try nevertheless */
+	WARN_ON_ONCE(!irqd_is_activated(d));
+
+	if (d->chip->irq_startup) {
+		ret = d->chip->irq_startup(d);
+		irq_state_clr_disabled(desc);
+		irq_state_clr_masked(desc);
+	} else {
+		irq_enable(desc);
+	}
+	irq_state_set_started(desc);
+	return ret;
+}
+
+int irq_startup(struct irq_desc *desc, bool resend, bool force)
+{
+	struct irq_data *d = irq_desc_get_irq_data(desc);
+	const struct cpumask *aff = irq_data_get_affinity_mask(d);
+	int ret = 0;
+
+	desc->depth = 0;
+
+	if (irqd_is_started(d)) {
+		irq_enable(desc);
+	} else {
+		switch (__irq_startup_managed(desc, aff, force)) {
+		case IRQ_STARTUP_NORMAL:
+			if (d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP)
+				irq_setup_affinity(desc);
+			ret = __irq_startup(desc);
+			if (!(d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP))
+				irq_setup_affinity(desc);
+			break;
+		case IRQ_STARTUP_MANAGED:
+			irq_do_set_affinity(d, aff, false);
+			ret = __irq_startup(desc);
+			break;
+		case IRQ_STARTUP_ABORT:
+			irqd_set_managed_shutdown(d);
+			return 0;
+		}
+	}
+	if (resend)
+		check_irq_resend(desc, false);
+
+	return ret;
+}
+
+int irq_activate(struct irq_desc *desc)
+{
+	struct irq_data *d = irq_desc_get_irq_data(desc);
+
+	if (!irqd_affinity_is_managed(d))
+		return irq_domain_activate_irq(d, false);
+	return 0;
+}
+
+int irq_activate_and_startup(struct irq_desc *desc, bool resend)
+{
+	if (WARN_ON(irq_activate(desc)))
+		return 0;
+	return irq_startup(desc, resend, IRQ_START_FORCE);
+}
+
+static void __irq_disable(struct irq_desc *desc, bool mask);
+
+void irq_shutdown(struct irq_desc *desc)
+{
+	if (irqd_is_started(&desc->irq_data)) {
+		desc->depth = 1;
+		if (desc->irq_data.chip->irq_shutdown) {
+			desc->irq_data.chip->irq_shutdown(&desc->irq_data);
+			irq_state_set_disabled(desc);
+			irq_state_set_masked(desc);
+		} else {
+			__irq_disable(desc, true);
+		}
+		irq_state_clr_started(desc);
+	}
+}
+
+
+void irq_shutdown_and_deactivate(struct irq_desc *desc)
+{
+	irq_shutdown(desc);
+	/*
+	 * This must be called even if the interrupt was never started up,
+	 * because the activation can happen before the interrupt is
+	 * available for request/startup. It has it's own state tracking so
+	 * it's safe to call it unconditionally.
+	 */
+	irq_domain_deactivate_irq(&desc->irq_data);
+}
+
+void irq_enable(struct irq_desc *desc)
+{
+	if (!irqd_irq_disabled(&desc->irq_data)) {
+		unmask_irq(desc);
+	} else {
+		irq_state_clr_disabled(desc);
+		if (desc->irq_data.chip->irq_enable) {
+			desc->irq_data.chip->irq_enable(&desc->irq_data);
+			irq_state_clr_masked(desc);
+		} else {
+			unmask_irq(desc);
+		}
+	}
+}
+
+static void __irq_disable(struct irq_desc *desc, bool mask)
+{
+	if (irqd_irq_disabled(&desc->irq_data)) {
+		if (mask)
+			mask_irq(desc);
+	} else {
+		irq_state_set_disabled(desc);
+		if (desc->irq_data.chip->irq_disable) {
+			desc->irq_data.chip->irq_disable(&desc->irq_data);
+			irq_state_set_masked(desc);
+		} else if (mask) {
+			mask_irq(desc);
+		}
+	}
+}
+
+/**
+ * irq_disable - Mark interrupt disabled
+ * @desc:	irq descriptor which should be disabled
+ *
+ * If the chip does not implement the irq_disable callback, we
+ * use a lazy disable approach. That means we mark the interrupt
+ * disabled, but leave the hardware unmasked. That's an
+ * optimization because we avoid the hardware access for the
+ * common case where no interrupt happens after we marked it
+ * disabled. If an interrupt happens, then the interrupt flow
+ * handler masks the line at the hardware level and marks it
+ * pending.
+ *
+ * If the interrupt chip does not implement the irq_disable callback,
+ * a driver can disable the lazy approach for a particular irq line by
+ * calling 'irq_set_status_flags(irq, IRQ_DISABLE_UNLAZY)'. This can
+ * be used for devices which cannot disable the interrupt at the
+ * device level under certain circumstances and have to use
+ * disable_irq[_nosync] instead.
+ */
+void irq_disable(struct irq_desc *desc)
+{
+	__irq_disable(desc, irq_settings_disable_unlazy(desc));
+}
+
+void irq_percpu_enable(struct irq_desc *desc, unsigned int cpu)
+{
+	if (desc->irq_data.chip->irq_enable)
+		desc->irq_data.chip->irq_enable(&desc->irq_data);
+	else
+		desc->irq_data.chip->irq_unmask(&desc->irq_data);
+	cpumask_set_cpu(cpu, desc->percpu_enabled);
+}
+
+void irq_percpu_disable(struct irq_desc *desc, unsigned int cpu)
+{
+	if (desc->irq_data.chip->irq_disable)
+		desc->irq_data.chip->irq_disable(&desc->irq_data);
+	else
+		desc->irq_data.chip->irq_mask(&desc->irq_data);
+	cpumask_clear_cpu(cpu, desc->percpu_enabled);
+}
+
+static inline void mask_ack_irq(struct irq_desc *desc)
+{
+	if (desc->irq_data.chip->irq_mask_ack) {
+		desc->irq_data.chip->irq_mask_ack(&desc->irq_data);
+		irq_state_set_masked(desc);
+	} else {
+		mask_irq(desc);
+		if (desc->irq_data.chip->irq_ack)
+			desc->irq_data.chip->irq_ack(&desc->irq_data);
+	}
+}
+
+void mask_irq(struct irq_desc *desc)
+{
+	if (irqd_irq_masked(&desc->irq_data))
+		return;
+
+	if (desc->irq_data.chip->irq_mask) {
+		desc->irq_data.chip->irq_mask(&desc->irq_data);
+		irq_state_set_masked(desc);
+	}
+}
+
+void unmask_irq(struct irq_desc *desc)
+{
+	if (!irqd_irq_masked(&desc->irq_data))
+		return;
+
+	if (desc->irq_data.chip->irq_unmask) {
+		desc->irq_data.chip->irq_unmask(&desc->irq_data);
+		irq_state_clr_masked(desc);
+	}
+}
+
+void unmask_threaded_irq(struct irq_desc *desc)
+{
+	struct irq_chip *chip = desc->irq_data.chip;
+
+	if (chip->flags & IRQCHIP_EOI_THREADED)
+		chip->irq_eoi(&desc->irq_data);
+
+	unmask_irq(desc);
+}
+
+/*
+ *	handle_nested_irq - Handle a nested irq from a irq thread
+ *	@irq:	the interrupt number
+ *
+ *	Handle interrupts which are nested into a threaded interrupt
+ *	handler. The handler function is called inside the calling
+ *	threads context.
+ */
+void handle_nested_irq(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	struct irqaction *action;
+	irqreturn_t action_ret;
+
+	might_sleep();
+
+	raw_spin_lock_irq(&desc->lock);
+
+	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+	action = desc->action;
+	if (unlikely(!action || irqd_irq_disabled(&desc->irq_data))) {
+		desc->istate |= IRQS_PENDING;
+		goto out_unlock;
+	}
+
+	kstat_incr_irqs_this_cpu(desc);
+	irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);
+	raw_spin_unlock_irq(&desc->lock);
+
+	action_ret = IRQ_NONE;
+	for_each_action_of_desc(desc, action)
+		action_ret |= action->thread_fn(action->irq, action->dev_id);
+
+	if (!irq_settings_no_debug(desc))
+		note_interrupt(desc, action_ret);
+
+	raw_spin_lock_irq(&desc->lock);
+	irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
+
+out_unlock:
+	raw_spin_unlock_irq(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_nested_irq);
+
+static bool irq_check_poll(struct irq_desc *desc)
+{
+	if (!(desc->istate & IRQS_POLL_INPROGRESS))
+		return false;
+	return irq_wait_for_poll(desc);
+}
+
+static bool irq_may_run(struct irq_desc *desc)
+{
+	unsigned int mask = IRQD_IRQ_INPROGRESS | IRQD_WAKEUP_ARMED;
+
+	/*
+	 * If the interrupt is not in progress and is not an armed
+	 * wakeup interrupt, proceed.
+	 */
+	if (!irqd_has_set(&desc->irq_data, mask))
+		return true;
+
+	/*
+	 * If the interrupt is an armed wakeup source, mark it pending
+	 * and suspended, disable it and notify the pm core about the
+	 * event.
+	 */
+	if (irq_pm_check_wakeup(desc))
+		return false;
+
+	/*
+	 * Handle a potential concurrent poll on a different core.
+	 */
+	return irq_check_poll(desc);
+}
+
+/**
+ *	handle_simple_irq - Simple and software-decoded IRQs.
+ *	@desc:	the interrupt description structure for this irq
+ *
+ *	Simple interrupts are either sent from a demultiplexing interrupt
+ *	handler or come from hardware, where no interrupt hardware control
+ *	is necessary.
+ *
+ *	Note: The caller is expected to handle the ack, clear, mask and
+ *	unmask issues if necessary.
+ */
+void handle_simple_irq(struct irq_desc *desc)
+{
+	raw_spin_lock(&desc->lock);
+
+	if (!irq_may_run(desc))
+		goto out_unlock;
+
+	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+	if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
+		desc->istate |= IRQS_PENDING;
+		goto out_unlock;
+	}
+
+	kstat_incr_irqs_this_cpu(desc);
+	handle_irq_event(desc);
+
+out_unlock:
+	raw_spin_unlock(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_simple_irq);
+
+/**
+ *	handle_untracked_irq - Simple and software-decoded IRQs.
+ *	@desc:	the interrupt description structure for this irq
+ *
+ *	Untracked interrupts are sent from a demultiplexing interrupt
+ *	handler when the demultiplexer does not know which device it its
+ *	multiplexed irq domain generated the interrupt. IRQ's handled
+ *	through here are not subjected to stats tracking, randomness, or
+ *	spurious interrupt detection.
+ *
+ *	Note: Like handle_simple_irq, the caller is expected to handle
+ *	the ack, clear, mask and unmask issues if necessary.
+ */
+void handle_untracked_irq(struct irq_desc *desc)
+{
+	raw_spin_lock(&desc->lock);
+
+	if (!irq_may_run(desc))
+		goto out_unlock;
+
+	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+	if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
+		desc->istate |= IRQS_PENDING;
+		goto out_unlock;
+	}
+
+	desc->istate &= ~IRQS_PENDING;
+	irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);
+	raw_spin_unlock(&desc->lock);
+
+	__handle_irq_event_percpu(desc);
+
+	raw_spin_lock(&desc->lock);
+	irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
+
+out_unlock:
+	raw_spin_unlock(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_untracked_irq);
+
+/*
+ * Called unconditionally from handle_level_irq() and only for oneshot
+ * interrupts from handle_fasteoi_irq()
+ */
+static void cond_unmask_irq(struct irq_desc *desc)
+{
+	/*
+	 * We need to unmask in the following cases:
+	 * - Standard level irq (IRQF_ONESHOT is not set)
+	 * - Oneshot irq which did not wake the thread (caused by a
+	 *   spurious interrupt or a primary handler handling it
+	 *   completely).
+	 */
+	if (!irqd_irq_disabled(&desc->irq_data) &&
+	    irqd_irq_masked(&desc->irq_data) && !desc->threads_oneshot)
+		unmask_irq(desc);
+}
+
+/**
+ *	handle_level_irq - Level type irq handler
+ *	@desc:	the interrupt description structure for this irq
+ *
+ *	Level type interrupts are active as long as the hardware line has
+ *	the active level. This may require to mask the interrupt and unmask
+ *	it after the associated handler has acknowledged the device, so the
+ *	interrupt line is back to inactive.
+ */
+void handle_level_irq(struct irq_desc *desc)
+{
+	raw_spin_lock(&desc->lock);
+	mask_ack_irq(desc);
+
+	if (!irq_may_run(desc))
+		goto out_unlock;
+
+	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+	/*
+	 * If its disabled or no action available
+	 * keep it masked and get out of here
+	 */
+	if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
+		desc->istate |= IRQS_PENDING;
+		goto out_unlock;
+	}
+
+	kstat_incr_irqs_this_cpu(desc);
+	handle_irq_event(desc);
+
+	cond_unmask_irq(desc);
+
+out_unlock:
+	raw_spin_unlock(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_level_irq);
+
+static void cond_unmask_eoi_irq(struct irq_desc *desc, struct irq_chip *chip)
+{
+	if (!(desc->istate & IRQS_ONESHOT)) {
+		chip->irq_eoi(&desc->irq_data);
+		return;
+	}
+	/*
+	 * We need to unmask in the following cases:
+	 * - Oneshot irq which did not wake the thread (caused by a
+	 *   spurious interrupt or a primary handler handling it
+	 *   completely).
+	 */
+	if (!irqd_irq_disabled(&desc->irq_data) &&
+	    irqd_irq_masked(&desc->irq_data) && !desc->threads_oneshot) {
+		chip->irq_eoi(&desc->irq_data);
+		unmask_irq(desc);
+	} else if (!(chip->flags & IRQCHIP_EOI_THREADED)) {
+		chip->irq_eoi(&desc->irq_data);
+	}
+}
+
+/**
+ *	handle_fasteoi_irq - irq handler for transparent controllers
+ *	@desc:	the interrupt description structure for this irq
+ *
+ *	Only a single callback will be issued to the chip: an ->eoi()
+ *	call when the interrupt has been serviced. This enables support
+ *	for modern forms of interrupt handlers, which handle the flow
+ *	details in hardware, transparently.
+ */
+void handle_fasteoi_irq(struct irq_desc *desc)
+{
+	struct irq_chip *chip = desc->irq_data.chip;
+
+	raw_spin_lock(&desc->lock);
+
+	if (!irq_may_run(desc))
+		goto out;
+
+	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+	/*
+	 * If its disabled or no action available
+	 * then mask it and get out of here:
+	 */
+	if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
+		desc->istate |= IRQS_PENDING;
+		mask_irq(desc);
+		goto out;
+	}
+
+	kstat_incr_irqs_this_cpu(desc);
+	if (desc->istate & IRQS_ONESHOT)
+		mask_irq(desc);
+
+	handle_irq_event(desc);
+
+	cond_unmask_eoi_irq(desc, chip);
+
+	raw_spin_unlock(&desc->lock);
+	return;
+out:
+	if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED))
+		chip->irq_eoi(&desc->irq_data);
+	raw_spin_unlock(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_fasteoi_irq);
+
+/**
+ *	handle_fasteoi_nmi - irq handler for NMI interrupt lines
+ *	@desc:	the interrupt description structure for this irq
+ *
+ *	A simple NMI-safe handler, considering the restrictions
+ *	from request_nmi.
+ *
+ *	Only a single callback will be issued to the chip: an ->eoi()
+ *	call when the interrupt has been serviced. This enables support
+ *	for modern forms of interrupt handlers, which handle the flow
+ *	details in hardware, transparently.
+ */
+void handle_fasteoi_nmi(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct irqaction *action = desc->action;
+	unsigned int irq = irq_desc_get_irq(desc);
+	irqreturn_t res;
+
+	__kstat_incr_irqs_this_cpu(desc);
+
+	trace_irq_handler_entry(irq, action);
+	/*
+	 * NMIs cannot be shared, there is only one action.
+	 */
+	res = action->handler(irq, action->dev_id);
+	trace_irq_handler_exit(irq, action, res);
+
+	if (chip->irq_eoi)
+		chip->irq_eoi(&desc->irq_data);
+}
+EXPORT_SYMBOL_GPL(handle_fasteoi_nmi);
+
+/**
+ *	handle_edge_irq - edge type IRQ handler
+ *	@desc:	the interrupt description structure for this irq
+ *
+ *	Interrupt occurs on the falling and/or rising edge of a hardware
+ *	signal. The occurrence is latched into the irq controller hardware
+ *	and must be acked in order to be reenabled. After the ack another
+ *	interrupt can happen on the same source even before the first one
+ *	is handled by the associated event handler. If this happens it
+ *	might be necessary to disable (mask) the interrupt depending on the
+ *	controller hardware. This requires to reenable the interrupt inside
+ *	of the loop which handles the interrupts which have arrived while
+ *	the handler was running. If all pending interrupts are handled, the
+ *	loop is left.
+ */
+void handle_edge_irq(struct irq_desc *desc)
+{
+	raw_spin_lock(&desc->lock);
+
+	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+	if (!irq_may_run(desc)) {
+		desc->istate |= IRQS_PENDING;
+		mask_ack_irq(desc);
+		goto out_unlock;
+	}
+
+	/*
+	 * If its disabled or no action available then mask it and get
+	 * out of here.
+	 */
+	if (irqd_irq_disabled(&desc->irq_data) || !desc->action) {
+		desc->istate |= IRQS_PENDING;
+		mask_ack_irq(desc);
+		goto out_unlock;
+	}
+
+	kstat_incr_irqs_this_cpu(desc);
+
+	/* Start handling the irq */
+	desc->irq_data.chip->irq_ack(&desc->irq_data);
+
+	do {
+		if (unlikely(!desc->action)) {
+			mask_irq(desc);
+			goto out_unlock;
+		}
+
+		/*
+		 * When another irq arrived while we were handling
+		 * one, we could have masked the irq.
+		 * Reenable it, if it was not disabled in meantime.
+		 */
+		if (unlikely(desc->istate & IRQS_PENDING)) {
+			if (!irqd_irq_disabled(&desc->irq_data) &&
+			    irqd_irq_masked(&desc->irq_data))
+				unmask_irq(desc);
+		}
+
+		handle_irq_event(desc);
+
+	} while ((desc->istate & IRQS_PENDING) &&
+		 !irqd_irq_disabled(&desc->irq_data));
+
+out_unlock:
+	raw_spin_unlock(&desc->lock);
+}
+EXPORT_SYMBOL(handle_edge_irq);
+
+#ifdef CONFIG_IRQ_EDGE_EOI_HANDLER
+/**
+ *	handle_edge_eoi_irq - edge eoi type IRQ handler
+ *	@desc:	the interrupt description structure for this irq
+ *
+ * Similar as the above handle_edge_irq, but using eoi and w/o the
+ * mask/unmask logic.
+ */
+void handle_edge_eoi_irq(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+
+	raw_spin_lock(&desc->lock);
+
+	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+	if (!irq_may_run(desc)) {
+		desc->istate |= IRQS_PENDING;
+		goto out_eoi;
+	}
+
+	/*
+	 * If its disabled or no action available then mask it and get
+	 * out of here.
+	 */
+	if (irqd_irq_disabled(&desc->irq_data) || !desc->action) {
+		desc->istate |= IRQS_PENDING;
+		goto out_eoi;
+	}
+
+	kstat_incr_irqs_this_cpu(desc);
+
+	do {
+		if (unlikely(!desc->action))
+			goto out_eoi;
+
+		handle_irq_event(desc);
+
+	} while ((desc->istate & IRQS_PENDING) &&
+		 !irqd_irq_disabled(&desc->irq_data));
+
+out_eoi:
+	chip->irq_eoi(&desc->irq_data);
+	raw_spin_unlock(&desc->lock);
+}
+#endif
+
+/**
+ *	handle_percpu_irq - Per CPU local irq handler
+ *	@desc:	the interrupt description structure for this irq
+ *
+ *	Per CPU interrupts on SMP machines without locking requirements
+ */
+void handle_percpu_irq(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+
+	/*
+	 * PER CPU interrupts are not serialized. Do not touch
+	 * desc->tot_count.
+	 */
+	__kstat_incr_irqs_this_cpu(desc);
+
+	if (chip->irq_ack)
+		chip->irq_ack(&desc->irq_data);
+
+	handle_irq_event_percpu(desc);
+
+	if (chip->irq_eoi)
+		chip->irq_eoi(&desc->irq_data);
+}
+
+/**
+ * handle_percpu_devid_irq - Per CPU local irq handler with per cpu dev ids
+ * @desc:	the interrupt description structure for this irq
+ *
+ * Per CPU interrupts on SMP machines without locking requirements. Same as
+ * handle_percpu_irq() above but with the following extras:
+ *
+ * action->percpu_dev_id is a pointer to percpu variables which
+ * contain the real device id for the cpu on which this handler is
+ * called
+ */
+void handle_percpu_devid_irq(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct irqaction *action = desc->action;
+	unsigned int irq = irq_desc_get_irq(desc);
+	irqreturn_t res;
+
+	/*
+	 * PER CPU interrupts are not serialized. Do not touch
+	 * desc->tot_count.
+	 */
+	__kstat_incr_irqs_this_cpu(desc);
+
+	if (chip->irq_ack)
+		chip->irq_ack(&desc->irq_data);
+
+	if (likely(action)) {
+		trace_irq_handler_entry(irq, action);
+		res = action->handler(irq, raw_cpu_ptr(action->percpu_dev_id));
+		trace_irq_handler_exit(irq, action, res);
+	} else {
+		unsigned int cpu = smp_processor_id();
+		bool enabled = cpumask_test_cpu(cpu, desc->percpu_enabled);
+
+		if (enabled)
+			irq_percpu_disable(desc, cpu);
+
+		pr_err_once("Spurious%s percpu IRQ%u on CPU%u\n",
+			    enabled ? " and unmasked" : "", irq, cpu);
+	}
+
+	if (chip->irq_eoi)
+		chip->irq_eoi(&desc->irq_data);
+}
+
+/**
+ * handle_percpu_devid_fasteoi_nmi - Per CPU local NMI handler with per cpu
+ *				     dev ids
+ * @desc:	the interrupt description structure for this irq
+ *
+ * Similar to handle_fasteoi_nmi, but handling the dev_id cookie
+ * as a percpu pointer.
+ */
+void handle_percpu_devid_fasteoi_nmi(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct irqaction *action = desc->action;
+	unsigned int irq = irq_desc_get_irq(desc);
+	irqreturn_t res;
+
+	__kstat_incr_irqs_this_cpu(desc);
+
+	trace_irq_handler_entry(irq, action);
+	res = action->handler(irq, raw_cpu_ptr(action->percpu_dev_id));
+	trace_irq_handler_exit(irq, action, res);
+
+	if (chip->irq_eoi)
+		chip->irq_eoi(&desc->irq_data);
+}
+
+static void
+__irq_do_set_handler(struct irq_desc *desc, irq_flow_handler_t handle,
+		     int is_chained, const char *name)
+{
+	if (!handle) {
+		handle = handle_bad_irq;
+	} else {
+		struct irq_data *irq_data = &desc->irq_data;
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+		/*
+		 * With hierarchical domains we might run into a
+		 * situation where the outermost chip is not yet set
+		 * up, but the inner chips are there.  Instead of
+		 * bailing we install the handler, but obviously we
+		 * cannot enable/startup the interrupt at this point.
+		 */
+		while (irq_data) {
+			if (irq_data->chip != &no_irq_chip)
+				break;
+			/*
+			 * Bail out if the outer chip is not set up
+			 * and the interrupt supposed to be started
+			 * right away.
+			 */
+			if (WARN_ON(is_chained))
+				return;
+			/* Try the parent */
+			irq_data = irq_data->parent_data;
+		}
+#endif
+		if (WARN_ON(!irq_data || irq_data->chip == &no_irq_chip))
+			return;
+	}
+
+	/* Uninstall? */
+	if (handle == handle_bad_irq) {
+		if (desc->irq_data.chip != &no_irq_chip)
+			mask_ack_irq(desc);
+		irq_state_set_disabled(desc);
+		if (is_chained) {
+			desc->action = NULL;
+			WARN_ON(irq_chip_pm_put(irq_desc_get_irq_data(desc)));
+		}
+		desc->depth = 1;
+	}
+	desc->handle_irq = handle;
+	desc->name = name;
+
+	if (handle != handle_bad_irq && is_chained) {
+		unsigned int type = irqd_get_trigger_type(&desc->irq_data);
+
+		/*
+		 * We're about to start this interrupt immediately,
+		 * hence the need to set the trigger configuration.
+		 * But the .set_type callback may have overridden the
+		 * flow handler, ignoring that we're dealing with a
+		 * chained interrupt. Reset it immediately because we
+		 * do know better.
+		 */
+		if (type != IRQ_TYPE_NONE) {
+			__irq_set_trigger(desc, type);
+			desc->handle_irq = handle;
+		}
+
+		irq_settings_set_noprobe(desc);
+		irq_settings_set_norequest(desc);
+		irq_settings_set_nothread(desc);
+		desc->action = &chained_action;
+		WARN_ON(irq_chip_pm_get(irq_desc_get_irq_data(desc)));
+		irq_activate_and_startup(desc, IRQ_RESEND);
+	}
+}
+
+void
+__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
+		  const char *name)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);
+
+	if (!desc)
+		return;
+
+	__irq_do_set_handler(desc, handle, is_chained, name);
+	irq_put_desc_busunlock(desc, flags);
+}
+EXPORT_SYMBOL_GPL(__irq_set_handler);
+
+void
+irq_set_chained_handler_and_data(unsigned int irq, irq_flow_handler_t handle,
+				 void *data)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);
+
+	if (!desc)
+		return;
+
+	desc->irq_common_data.handler_data = data;
+	__irq_do_set_handler(desc, handle, 1, NULL);
+
+	irq_put_desc_busunlock(desc, flags);
+}
+EXPORT_SYMBOL_GPL(irq_set_chained_handler_and_data);
+
+void
+irq_set_chip_and_handler_name(unsigned int irq, const struct irq_chip *chip,
+			      irq_flow_handler_t handle, const char *name)
+{
+	irq_set_chip(irq, chip);
+	__irq_set_handler(irq, handle, 0, name);
+}
+EXPORT_SYMBOL_GPL(irq_set_chip_and_handler_name);
+
+void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set)
+{
+	unsigned long flags, trigger, tmp;
+	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+
+	if (!desc)
+		return;
+
+	/*
+	 * Warn when a driver sets the no autoenable flag on an already
+	 * active interrupt.
+	 */
+	WARN_ON_ONCE(!desc->depth && (set & _IRQ_NOAUTOEN));
+
+	irq_settings_clr_and_set(desc, clr, set);
+
+	trigger = irqd_get_trigger_type(&desc->irq_data);
+
+	irqd_clear(&desc->irq_data, IRQD_NO_BALANCING | IRQD_PER_CPU |
+		   IRQD_TRIGGER_MASK | IRQD_LEVEL | IRQD_MOVE_PCNTXT);
+	if (irq_settings_has_no_balance_set(desc))
+		irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
+	if (irq_settings_is_per_cpu(desc))
+		irqd_set(&desc->irq_data, IRQD_PER_CPU);
+	if (irq_settings_can_move_pcntxt(desc))
+		irqd_set(&desc->irq_data, IRQD_MOVE_PCNTXT);
+	if (irq_settings_is_level(desc))
+		irqd_set(&desc->irq_data, IRQD_LEVEL);
+
+	tmp = irq_settings_get_trigger_mask(desc);
+	if (tmp != IRQ_TYPE_NONE)
+		trigger = tmp;
+
+	irqd_set(&desc->irq_data, trigger);
+
+	irq_put_desc_unlock(desc, flags);
+}
+EXPORT_SYMBOL_GPL(irq_modify_status);
+
+#ifdef CONFIG_DEPRECATED_IRQ_CPU_ONOFFLINE
+/**
+ *	irq_cpu_online - Invoke all irq_cpu_online functions.
+ *
+ *	Iterate through all irqs and invoke the chip.irq_cpu_online()
+ *	for each.
+ */
+void irq_cpu_online(void)
+{
+	struct irq_desc *desc;
+	struct irq_chip *chip;
+	unsigned long flags;
+	unsigned int irq;
+
+	for_each_active_irq(irq) {
+		desc = irq_to_desc(irq);
+		if (!desc)
+			continue;
+
+		raw_spin_lock_irqsave(&desc->lock, flags);
+
+		chip = irq_data_get_irq_chip(&desc->irq_data);
+		if (chip && chip->irq_cpu_online &&
+		    (!(chip->flags & IRQCHIP_ONOFFLINE_ENABLED) ||
+		     !irqd_irq_disabled(&desc->irq_data)))
+			chip->irq_cpu_online(&desc->irq_data);
+
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+	}
+}
+
+/**
+ *	irq_cpu_offline - Invoke all irq_cpu_offline functions.
+ *
+ *	Iterate through all irqs and invoke the chip.irq_cpu_offline()
+ *	for each.
+ */
+void irq_cpu_offline(void)
+{
+	struct irq_desc *desc;
+	struct irq_chip *chip;
+	unsigned long flags;
+	unsigned int irq;
+
+	for_each_active_irq(irq) {
+		desc = irq_to_desc(irq);
+		if (!desc)
+			continue;
+
+		raw_spin_lock_irqsave(&desc->lock, flags);
+
+		chip = irq_data_get_irq_chip(&desc->irq_data);
+		if (chip && chip->irq_cpu_offline &&
+		    (!(chip->flags & IRQCHIP_ONOFFLINE_ENABLED) ||
+		     !irqd_irq_disabled(&desc->irq_data)))
+			chip->irq_cpu_offline(&desc->irq_data);
+
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+	}
+}
+#endif
+
+#ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+
+#ifdef CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS
+/**
+ *	handle_fasteoi_ack_irq - irq handler for edge hierarchy
+ *	stacked on transparent controllers
+ *
+ *	@desc:	the interrupt description structure for this irq
+ *
+ *	Like handle_fasteoi_irq(), but for use with hierarchy where
+ *	the irq_chip also needs to have its ->irq_ack() function
+ *	called.
+ */
+void handle_fasteoi_ack_irq(struct irq_desc *desc)
+{
+	struct irq_chip *chip = desc->irq_data.chip;
+
+	raw_spin_lock(&desc->lock);
+
+	if (!irq_may_run(desc))
+		goto out;
+
+	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+	/*
+	 * If its disabled or no action available
+	 * then mask it and get out of here:
+	 */
+	if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
+		desc->istate |= IRQS_PENDING;
+		mask_irq(desc);
+		goto out;
+	}
+
+	kstat_incr_irqs_this_cpu(desc);
+	if (desc->istate & IRQS_ONESHOT)
+		mask_irq(desc);
+
+	/* Start handling the irq */
+	desc->irq_data.chip->irq_ack(&desc->irq_data);
+
+	handle_irq_event(desc);
+
+	cond_unmask_eoi_irq(desc, chip);
+
+	raw_spin_unlock(&desc->lock);
+	return;
+out:
+	if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED))
+		chip->irq_eoi(&desc->irq_data);
+	raw_spin_unlock(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_fasteoi_ack_irq);
+
+/**
+ *	handle_fasteoi_mask_irq - irq handler for level hierarchy
+ *	stacked on transparent controllers
+ *
+ *	@desc:	the interrupt description structure for this irq
+ *
+ *	Like handle_fasteoi_irq(), but for use with hierarchy where
+ *	the irq_chip also needs to have its ->irq_mask_ack() function
+ *	called.
+ */
+void handle_fasteoi_mask_irq(struct irq_desc *desc)
+{
+	struct irq_chip *chip = desc->irq_data.chip;
+
+	raw_spin_lock(&desc->lock);
+	mask_ack_irq(desc);
+
+	if (!irq_may_run(desc))
+		goto out;
+
+	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+	/*
+	 * If its disabled or no action available
+	 * then mask it and get out of here:
+	 */
+	if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
+		desc->istate |= IRQS_PENDING;
+		mask_irq(desc);
+		goto out;
+	}
+
+	kstat_incr_irqs_this_cpu(desc);
+	if (desc->istate & IRQS_ONESHOT)
+		mask_irq(desc);
+
+	handle_irq_event(desc);
+
+	cond_unmask_eoi_irq(desc, chip);
+
+	raw_spin_unlock(&desc->lock);
+	return;
+out:
+	if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED))
+		chip->irq_eoi(&desc->irq_data);
+	raw_spin_unlock(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_fasteoi_mask_irq);
+
+#endif /* CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS */
+
+/**
+ * irq_chip_set_parent_state - set the state of a parent interrupt.
+ *
+ * @data: Pointer to interrupt specific data
+ * @which: State to be restored (one of IRQCHIP_STATE_*)
+ * @val: Value corresponding to @which
+ *
+ * Conditional success, if the underlying irqchip does not implement it.
+ */
+int irq_chip_set_parent_state(struct irq_data *data,
+			      enum irqchip_irq_state which,
+			      bool val)
+{
+	data = data->parent_data;
+
+	if (!data || !data->chip->irq_set_irqchip_state)
+		return 0;
+
+	return data->chip->irq_set_irqchip_state(data, which, val);
+}
+EXPORT_SYMBOL_GPL(irq_chip_set_parent_state);
+
+/**
+ * irq_chip_get_parent_state - get the state of a parent interrupt.
+ *
+ * @data: Pointer to interrupt specific data
+ * @which: one of IRQCHIP_STATE_* the caller wants to know
+ * @state: a pointer to a boolean where the state is to be stored
+ *
+ * Conditional success, if the underlying irqchip does not implement it.
+ */
+int irq_chip_get_parent_state(struct irq_data *data,
+			      enum irqchip_irq_state which,
+			      bool *state)
+{
+	data = data->parent_data;
+
+	if (!data || !data->chip->irq_get_irqchip_state)
+		return 0;
+
+	return data->chip->irq_get_irqchip_state(data, which, state);
+}
+EXPORT_SYMBOL_GPL(irq_chip_get_parent_state);
+
+/**
+ * irq_chip_enable_parent - Enable the parent interrupt (defaults to unmask if
+ * NULL)
+ * @data:	Pointer to interrupt specific data
+ */
+void irq_chip_enable_parent(struct irq_data *data)
+{
+	data = data->parent_data;
+	if (data->chip->irq_enable)
+		data->chip->irq_enable(data);
+	else
+		data->chip->irq_unmask(data);
+}
+EXPORT_SYMBOL_GPL(irq_chip_enable_parent);
+
+/**
+ * irq_chip_disable_parent - Disable the parent interrupt (defaults to mask if
+ * NULL)
+ * @data:	Pointer to interrupt specific data
+ */
+void irq_chip_disable_parent(struct irq_data *data)
+{
+	data = data->parent_data;
+	if (data->chip->irq_disable)
+		data->chip->irq_disable(data);
+	else
+		data->chip->irq_mask(data);
+}
+EXPORT_SYMBOL_GPL(irq_chip_disable_parent);
+
+/**
+ * irq_chip_ack_parent - Acknowledge the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ */
+void irq_chip_ack_parent(struct irq_data *data)
+{
+	data = data->parent_data;
+	data->chip->irq_ack(data);
+}
+EXPORT_SYMBOL_GPL(irq_chip_ack_parent);
+
+/**
+ * irq_chip_mask_parent - Mask the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ */
+void irq_chip_mask_parent(struct irq_data *data)
+{
+	data = data->parent_data;
+	data->chip->irq_mask(data);
+}
+EXPORT_SYMBOL_GPL(irq_chip_mask_parent);
+
+/**
+ * irq_chip_mask_ack_parent - Mask and acknowledge the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ */
+void irq_chip_mask_ack_parent(struct irq_data *data)
+{
+	data = data->parent_data;
+	data->chip->irq_mask_ack(data);
+}
+EXPORT_SYMBOL_GPL(irq_chip_mask_ack_parent);
+
+/**
+ * irq_chip_unmask_parent - Unmask the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ */
+void irq_chip_unmask_parent(struct irq_data *data)
+{
+	data = data->parent_data;
+	data->chip->irq_unmask(data);
+}
+EXPORT_SYMBOL_GPL(irq_chip_unmask_parent);
+
+/**
+ * irq_chip_eoi_parent - Invoke EOI on the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ */
+void irq_chip_eoi_parent(struct irq_data *data)
+{
+	data = data->parent_data;
+	data->chip->irq_eoi(data);
+}
+EXPORT_SYMBOL_GPL(irq_chip_eoi_parent);
+
+/**
+ * irq_chip_set_affinity_parent - Set affinity on the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ * @dest:	The affinity mask to set
+ * @force:	Flag to enforce setting (disable online checks)
+ *
+ * Conditional, as the underlying parent chip might not implement it.
+ */
+int irq_chip_set_affinity_parent(struct irq_data *data,
+				 const struct cpumask *dest, bool force)
+{
+	data = data->parent_data;
+	if (data->chip->irq_set_affinity)
+		return data->chip->irq_set_affinity(data, dest, force);
+
+	return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(irq_chip_set_affinity_parent);
+
+/**
+ * irq_chip_set_type_parent - Set IRQ type on the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ * @type:	IRQ_TYPE_{LEVEL,EDGE}_* value - see include/linux/irq.h
+ *
+ * Conditional, as the underlying parent chip might not implement it.
+ */
+int irq_chip_set_type_parent(struct irq_data *data, unsigned int type)
+{
+	data = data->parent_data;
+
+	if (data->chip->irq_set_type)
+		return data->chip->irq_set_type(data, type);
+
+	return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(irq_chip_set_type_parent);
+
+/**
+ * irq_chip_retrigger_hierarchy - Retrigger an interrupt in hardware
+ * @data:	Pointer to interrupt specific data
+ *
+ * Iterate through the domain hierarchy of the interrupt and check
+ * whether a hw retrigger function exists. If yes, invoke it.
+ */
+int irq_chip_retrigger_hierarchy(struct irq_data *data)
+{
+	for (data = data->parent_data; data; data = data->parent_data)
+		if (data->chip && data->chip->irq_retrigger)
+			return data->chip->irq_retrigger(data);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_chip_retrigger_hierarchy);
+
+/**
+ * irq_chip_set_vcpu_affinity_parent - Set vcpu affinity on the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ * @vcpu_info:	The vcpu affinity information
+ */
+int irq_chip_set_vcpu_affinity_parent(struct irq_data *data, void *vcpu_info)
+{
+	data = data->parent_data;
+	if (data->chip->irq_set_vcpu_affinity)
+		return data->chip->irq_set_vcpu_affinity(data, vcpu_info);
+
+	return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(irq_chip_set_vcpu_affinity_parent);
+/**
+ * irq_chip_set_wake_parent - Set/reset wake-up on the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ * @on:		Whether to set or reset the wake-up capability of this irq
+ *
+ * Conditional, as the underlying parent chip might not implement it.
+ */
+int irq_chip_set_wake_parent(struct irq_data *data, unsigned int on)
+{
+	data = data->parent_data;
+
+	if (data->chip->flags & IRQCHIP_SKIP_SET_WAKE)
+		return 0;
+
+	if (data->chip->irq_set_wake)
+		return data->chip->irq_set_wake(data, on);
+
+	return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(irq_chip_set_wake_parent);
+
+/**
+ * irq_chip_request_resources_parent - Request resources on the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ */
+int irq_chip_request_resources_parent(struct irq_data *data)
+{
+	data = data->parent_data;
+
+	if (data->chip->irq_request_resources)
+		return data->chip->irq_request_resources(data);
+
+	/* no error on missing optional irq_chip::irq_request_resources */
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_chip_request_resources_parent);
+
+/**
+ * irq_chip_release_resources_parent - Release resources on the parent interrupt
+ * @data:	Pointer to interrupt specific data
+ */
+void irq_chip_release_resources_parent(struct irq_data *data)
+{
+	data = data->parent_data;
+	if (data->chip->irq_release_resources)
+		data->chip->irq_release_resources(data);
+}
+EXPORT_SYMBOL_GPL(irq_chip_release_resources_parent);
+#endif
+
+/**
+ * irq_chip_compose_msi_msg - Compose msi message for a irq chip
+ * @data:	Pointer to interrupt specific data
+ * @msg:	Pointer to the MSI message
+ *
+ * For hierarchical domains we find the first chip in the hierarchy
+ * which implements the irq_compose_msi_msg callback. For non
+ * hierarchical we use the top level chip.
+ */
+int irq_chip_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	struct irq_data *pos;
+
+	for (pos = NULL; !pos && data; data = irqd_get_parent_data(data)) {
+		if (data->chip && data->chip->irq_compose_msi_msg)
+			pos = data;
+	}
+
+	if (!pos)
+		return -ENOSYS;
+
+	pos->chip->irq_compose_msi_msg(pos, msg);
+	return 0;
+}
+
+static struct device *irq_get_parent_device(struct irq_data *data)
+{
+	if (data->domain)
+		return data->domain->dev;
+
+	return NULL;
+}
+
+/**
+ * irq_chip_pm_get - Enable power for an IRQ chip
+ * @data:	Pointer to interrupt specific data
+ *
+ * Enable the power to the IRQ chip referenced by the interrupt data
+ * structure.
+ */
+int irq_chip_pm_get(struct irq_data *data)
+{
+	struct device *dev = irq_get_parent_device(data);
+	int retval = 0;
+
+	if (IS_ENABLED(CONFIG_PM) && dev)
+		retval = pm_runtime_resume_and_get(dev);
+
+	return retval;
+}
+
+/**
+ * irq_chip_pm_put - Disable power for an IRQ chip
+ * @data:	Pointer to interrupt specific data
+ *
+ * Disable the power to the IRQ chip referenced by the interrupt data
+ * structure, belongs. Note that power will only be disabled, once this
+ * function has been called for all IRQs that have called irq_chip_pm_get().
+ */
+int irq_chip_pm_put(struct irq_data *data)
+{
+	struct device *dev = irq_get_parent_device(data);
+	int retval = 0;
+
+	if (IS_ENABLED(CONFIG_PM) && dev)
+		retval = pm_runtime_put(dev);
+
+	return (retval < 0) ? retval : 0;
+}
diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c
new file mode 100644
index 000000000..1ed2b1739
--- /dev/null
+++ b/kernel/irq/cpuhotplug.c
@@ -0,0 +1,233 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic cpu hotunplug interrupt migration code copied from the
+ * arch/arm implementation
+ *
+ * Copyright (C) Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/interrupt.h>
+#include <linux/ratelimit.h>
+#include <linux/irq.h>
+#include <linux/sched/isolation.h>
+
+#include "internals.h"
+
+/* For !GENERIC_IRQ_EFFECTIVE_AFF_MASK this looks at general affinity mask */
+static inline bool irq_needs_fixup(struct irq_data *d)
+{
+	const struct cpumask *m = irq_data_get_effective_affinity_mask(d);
+	unsigned int cpu = smp_processor_id();
+
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	/*
+	 * The cpumask_empty() check is a workaround for interrupt chips,
+	 * which do not implement effective affinity, but the architecture has
+	 * enabled the config switch. Use the general affinity mask instead.
+	 */
+	if (cpumask_empty(m))
+		m = irq_data_get_affinity_mask(d);
+
+	/*
+	 * Sanity check. If the mask is not empty when excluding the outgoing
+	 * CPU then it must contain at least one online CPU. The outgoing CPU
+	 * has been removed from the online mask already.
+	 */
+	if (cpumask_any_but(m, cpu) < nr_cpu_ids &&
+	    cpumask_any_and(m, cpu_online_mask) >= nr_cpu_ids) {
+		/*
+		 * If this happens then there was a missed IRQ fixup at some
+		 * point. Warn about it and enforce fixup.
+		 */
+		pr_warn("Eff. affinity %*pbl of IRQ %u contains only offline CPUs after offlining CPU %u\n",
+			cpumask_pr_args(m), d->irq, cpu);
+		return true;
+	}
+#endif
+	return cpumask_test_cpu(cpu, m);
+}
+
+static bool migrate_one_irq(struct irq_desc *desc)
+{
+	struct irq_data *d = irq_desc_get_irq_data(desc);
+	struct irq_chip *chip = irq_data_get_irq_chip(d);
+	bool maskchip = !irq_can_move_pcntxt(d) && !irqd_irq_masked(d);
+	const struct cpumask *affinity;
+	bool brokeaff = false;
+	int err;
+
+	/*
+	 * IRQ chip might be already torn down, but the irq descriptor is
+	 * still in the radix tree. Also if the chip has no affinity setter,
+	 * nothing can be done here.
+	 */
+	if (!chip || !chip->irq_set_affinity) {
+		pr_debug("IRQ %u: Unable to migrate away\n", d->irq);
+		return false;
+	}
+
+	/*
+	 * No move required, if:
+	 * - Interrupt is per cpu
+	 * - Interrupt is not started
+	 * - Affinity mask does not include this CPU.
+	 *
+	 * Note: Do not check desc->action as this might be a chained
+	 * interrupt.
+	 */
+	if (irqd_is_per_cpu(d) || !irqd_is_started(d) || !irq_needs_fixup(d)) {
+		/*
+		 * If an irq move is pending, abort it if the dying CPU is
+		 * the sole target.
+		 */
+		irq_fixup_move_pending(desc, false);
+		return false;
+	}
+
+	/*
+	 * Complete an eventually pending irq move cleanup. If this
+	 * interrupt was moved in hard irq context, then the vectors need
+	 * to be cleaned up. It can't wait until this interrupt actually
+	 * happens and this CPU was involved.
+	 */
+	irq_force_complete_move(desc);
+
+	/*
+	 * If there is a setaffinity pending, then try to reuse the pending
+	 * mask, so the last change of the affinity does not get lost. If
+	 * there is no move pending or the pending mask does not contain
+	 * any online CPU, use the current affinity mask.
+	 */
+	if (irq_fixup_move_pending(desc, true))
+		affinity = irq_desc_get_pending_mask(desc);
+	else
+		affinity = irq_data_get_affinity_mask(d);
+
+	/* Mask the chip for interrupts which cannot move in process context */
+	if (maskchip && chip->irq_mask)
+		chip->irq_mask(d);
+
+	if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
+		/*
+		 * If the interrupt is managed, then shut it down and leave
+		 * the affinity untouched.
+		 */
+		if (irqd_affinity_is_managed(d)) {
+			irqd_set_managed_shutdown(d);
+			irq_shutdown_and_deactivate(desc);
+			return false;
+		}
+		affinity = cpu_online_mask;
+		brokeaff = true;
+	}
+	/*
+	 * Do not set the force argument of irq_do_set_affinity() as this
+	 * disables the masking of offline CPUs from the supplied affinity
+	 * mask and therefore might keep/reassign the irq to the outgoing
+	 * CPU.
+	 */
+	err = irq_do_set_affinity(d, affinity, false);
+	if (err) {
+		pr_warn_ratelimited("IRQ%u: set affinity failed(%d).\n",
+				    d->irq, err);
+		brokeaff = false;
+	}
+
+	if (maskchip && chip->irq_unmask)
+		chip->irq_unmask(d);
+
+	return brokeaff;
+}
+
+/**
+ * irq_migrate_all_off_this_cpu - Migrate irqs away from offline cpu
+ *
+ * The current CPU has been marked offline.  Migrate IRQs off this CPU.
+ * If the affinity settings do not allow other CPUs, force them onto any
+ * available CPU.
+ *
+ * Note: we must iterate over all IRQs, whether they have an attached
+ * action structure or not, as we need to get chained interrupts too.
+ */
+void irq_migrate_all_off_this_cpu(void)
+{
+	struct irq_desc *desc;
+	unsigned int irq;
+
+	for_each_active_irq(irq) {
+		bool affinity_broken;
+
+		desc = irq_to_desc(irq);
+		raw_spin_lock(&desc->lock);
+		affinity_broken = migrate_one_irq(desc);
+		raw_spin_unlock(&desc->lock);
+
+		if (affinity_broken) {
+			pr_debug_ratelimited("IRQ %u: no longer affine to CPU%u\n",
+					    irq, smp_processor_id());
+		}
+	}
+}
+
+static bool hk_should_isolate(struct irq_data *data, unsigned int cpu)
+{
+	const struct cpumask *hk_mask;
+
+	if (!housekeeping_enabled(HK_TYPE_MANAGED_IRQ))
+		return false;
+
+	hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);
+	if (cpumask_subset(irq_data_get_effective_affinity_mask(data), hk_mask))
+		return false;
+
+	return cpumask_test_cpu(cpu, hk_mask);
+}
+
+static void irq_restore_affinity_of_irq(struct irq_desc *desc, unsigned int cpu)
+{
+	struct irq_data *data = irq_desc_get_irq_data(desc);
+	const struct cpumask *affinity = irq_data_get_affinity_mask(data);
+
+	if (!irqd_affinity_is_managed(data) || !desc->action ||
+	    !irq_data_get_irq_chip(data) || !cpumask_test_cpu(cpu, affinity))
+		return;
+
+	if (irqd_is_managed_and_shutdown(data)) {
+		irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
+		return;
+	}
+
+	/*
+	 * If the interrupt can only be directed to a single target
+	 * CPU then it is already assigned to a CPU in the affinity
+	 * mask. No point in trying to move it around unless the
+	 * isolation mechanism requests to move it to an upcoming
+	 * housekeeping CPU.
+	 */
+	if (!irqd_is_single_target(data) || hk_should_isolate(data, cpu))
+		irq_set_affinity_locked(data, affinity, false);
+}
+
+/**
+ * irq_affinity_online_cpu - Restore affinity for managed interrupts
+ * @cpu:	Upcoming CPU for which interrupts should be restored
+ */
+int irq_affinity_online_cpu(unsigned int cpu)
+{
+	struct irq_desc *desc;
+	unsigned int irq;
+
+	irq_lock_sparse();
+	for_each_active_irq(irq) {
+		desc = irq_to_desc(irq);
+		raw_spin_lock_irq(&desc->lock);
+		irq_restore_affinity_of_irq(desc, cpu);
+		raw_spin_unlock_irq(&desc->lock);
+	}
+	irq_unlock_sparse();
+
+	return 0;
+}
diff --git a/kernel/irq/debug.h b/kernel/irq/debug.h
new file mode 100644
index 000000000..8ccb326d2
--- /dev/null
+++ b/kernel/irq/debug.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Debugging printout:
+ */
+
+#define ___P(f) if (desc->status_use_accessors & f) printk("%14s set\n", #f)
+#define ___PS(f) if (desc->istate & f) printk("%14s set\n", #f)
+/* FIXME */
+#define ___PD(f) do { } while (0)
+
+static inline void print_irq_desc(unsigned int irq, struct irq_desc *desc)
+{
+	static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 5);
+
+	if (!__ratelimit(&ratelimit))
+		return;
+
+	printk("irq %d, desc: %p, depth: %d, count: %d, unhandled: %d\n",
+		irq, desc, desc->depth, desc->irq_count, desc->irqs_unhandled);
+	printk("->handle_irq():  %p, %pS\n",
+		desc->handle_irq, desc->handle_irq);
+	printk("->irq_data.chip(): %p, %pS\n",
+		desc->irq_data.chip, desc->irq_data.chip);
+	printk("->action(): %p\n", desc->action);
+	if (desc->action) {
+		printk("->action->handler(): %p, %pS\n",
+			desc->action->handler, desc->action->handler);
+	}
+
+	___P(IRQ_LEVEL);
+	___P(IRQ_PER_CPU);
+	___P(IRQ_NOPROBE);
+	___P(IRQ_NOREQUEST);
+	___P(IRQ_NOTHREAD);
+	___P(IRQ_NOAUTOEN);
+
+	___PS(IRQS_AUTODETECT);
+	___PS(IRQS_REPLAY);
+	___PS(IRQS_WAITING);
+	___PS(IRQS_PENDING);
+
+	___PD(IRQS_INPROGRESS);
+	___PD(IRQS_DISABLED);
+	___PD(IRQS_MASKED);
+}
+
+#undef ___P
+#undef ___PS
+#undef ___PD
diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c
new file mode 100644
index 000000000..0b78fac88
--- /dev/null
+++ b/kernel/irq/debugfs.c
@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright 2017 Thomas Gleixner <tglx@linutronix.de>
+
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/uaccess.h>
+
+#include "internals.h"
+
+static struct dentry *irq_dir;
+
+struct irq_bit_descr {
+	unsigned int	mask;
+	char		*name;
+};
+#define BIT_MASK_DESCR(m)	{ .mask = m, .name = #m }
+
+static void irq_debug_show_bits(struct seq_file *m, int ind, unsigned int state,
+				const struct irq_bit_descr *sd, int size)
+{
+	int i;
+
+	for (i = 0; i < size; i++, sd++) {
+		if (state & sd->mask)
+			seq_printf(m, "%*s%s\n", ind + 12, "", sd->name);
+	}
+}
+
+#ifdef CONFIG_SMP
+static void irq_debug_show_masks(struct seq_file *m, struct irq_desc *desc)
+{
+	struct irq_data *data = irq_desc_get_irq_data(desc);
+	const struct cpumask *msk;
+
+	msk = irq_data_get_affinity_mask(data);
+	seq_printf(m, "affinity: %*pbl\n", cpumask_pr_args(msk));
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	msk = irq_data_get_effective_affinity_mask(data);
+	seq_printf(m, "effectiv: %*pbl\n", cpumask_pr_args(msk));
+#endif
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+	msk = desc->pending_mask;
+	seq_printf(m, "pending:  %*pbl\n", cpumask_pr_args(msk));
+#endif
+}
+#else
+static void irq_debug_show_masks(struct seq_file *m, struct irq_desc *desc) { }
+#endif
+
+static const struct irq_bit_descr irqchip_flags[] = {
+	BIT_MASK_DESCR(IRQCHIP_SET_TYPE_MASKED),
+	BIT_MASK_DESCR(IRQCHIP_EOI_IF_HANDLED),
+	BIT_MASK_DESCR(IRQCHIP_MASK_ON_SUSPEND),
+	BIT_MASK_DESCR(IRQCHIP_ONOFFLINE_ENABLED),
+	BIT_MASK_DESCR(IRQCHIP_SKIP_SET_WAKE),
+	BIT_MASK_DESCR(IRQCHIP_ONESHOT_SAFE),
+	BIT_MASK_DESCR(IRQCHIP_EOI_THREADED),
+	BIT_MASK_DESCR(IRQCHIP_SUPPORTS_LEVEL_MSI),
+	BIT_MASK_DESCR(IRQCHIP_SUPPORTS_NMI),
+	BIT_MASK_DESCR(IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND),
+	BIT_MASK_DESCR(IRQCHIP_IMMUTABLE),
+};
+
+static void
+irq_debug_show_chip(struct seq_file *m, struct irq_data *data, int ind)
+{
+	struct irq_chip *chip = data->chip;
+
+	if (!chip) {
+		seq_printf(m, "chip: None\n");
+		return;
+	}
+	seq_printf(m, "%*schip:    ", ind, "");
+	if (chip->irq_print_chip)
+		chip->irq_print_chip(data, m);
+	else
+		seq_printf(m, "%s", chip->name);
+	seq_printf(m, "\n%*sflags:   0x%lx\n", ind + 1, "", chip->flags);
+	irq_debug_show_bits(m, ind, chip->flags, irqchip_flags,
+			    ARRAY_SIZE(irqchip_flags));
+}
+
+static void
+irq_debug_show_data(struct seq_file *m, struct irq_data *data, int ind)
+{
+	seq_printf(m, "%*sdomain:  %s\n", ind, "",
+		   data->domain ? data->domain->name : "");
+	seq_printf(m, "%*shwirq:   0x%lx\n", ind + 1, "", data->hwirq);
+	irq_debug_show_chip(m, data, ind + 1);
+	if (data->domain && data->domain->ops && data->domain->ops->debug_show)
+		data->domain->ops->debug_show(m, NULL, data, ind + 1);
+#ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+	if (!data->parent_data)
+		return;
+	seq_printf(m, "%*sparent:\n", ind + 1, "");
+	irq_debug_show_data(m, data->parent_data, ind + 4);
+#endif
+}
+
+static const struct irq_bit_descr irqdata_states[] = {
+	BIT_MASK_DESCR(IRQ_TYPE_EDGE_RISING),
+	BIT_MASK_DESCR(IRQ_TYPE_EDGE_FALLING),
+	BIT_MASK_DESCR(IRQ_TYPE_LEVEL_HIGH),
+	BIT_MASK_DESCR(IRQ_TYPE_LEVEL_LOW),
+	BIT_MASK_DESCR(IRQD_LEVEL),
+
+	BIT_MASK_DESCR(IRQD_ACTIVATED),
+	BIT_MASK_DESCR(IRQD_IRQ_STARTED),
+	BIT_MASK_DESCR(IRQD_IRQ_DISABLED),
+	BIT_MASK_DESCR(IRQD_IRQ_MASKED),
+	BIT_MASK_DESCR(IRQD_IRQ_INPROGRESS),
+
+	BIT_MASK_DESCR(IRQD_PER_CPU),
+	BIT_MASK_DESCR(IRQD_NO_BALANCING),
+
+	BIT_MASK_DESCR(IRQD_SINGLE_TARGET),
+	BIT_MASK_DESCR(IRQD_MOVE_PCNTXT),
+	BIT_MASK_DESCR(IRQD_AFFINITY_SET),
+	BIT_MASK_DESCR(IRQD_SETAFFINITY_PENDING),
+	BIT_MASK_DESCR(IRQD_AFFINITY_MANAGED),
+	BIT_MASK_DESCR(IRQD_AFFINITY_ON_ACTIVATE),
+	BIT_MASK_DESCR(IRQD_MANAGED_SHUTDOWN),
+	BIT_MASK_DESCR(IRQD_CAN_RESERVE),
+
+	BIT_MASK_DESCR(IRQD_FORWARDED_TO_VCPU),
+
+	BIT_MASK_DESCR(IRQD_WAKEUP_STATE),
+	BIT_MASK_DESCR(IRQD_WAKEUP_ARMED),
+
+	BIT_MASK_DESCR(IRQD_DEFAULT_TRIGGER_SET),
+
+	BIT_MASK_DESCR(IRQD_HANDLE_ENFORCE_IRQCTX),
+
+	BIT_MASK_DESCR(IRQD_IRQ_ENABLED_ON_SUSPEND),
+};
+
+static const struct irq_bit_descr irqdesc_states[] = {
+	BIT_MASK_DESCR(_IRQ_NOPROBE),
+	BIT_MASK_DESCR(_IRQ_NOREQUEST),
+	BIT_MASK_DESCR(_IRQ_NOTHREAD),
+	BIT_MASK_DESCR(_IRQ_NOAUTOEN),
+	BIT_MASK_DESCR(_IRQ_NESTED_THREAD),
+	BIT_MASK_DESCR(_IRQ_PER_CPU_DEVID),
+	BIT_MASK_DESCR(_IRQ_IS_POLLED),
+	BIT_MASK_DESCR(_IRQ_DISABLE_UNLAZY),
+	BIT_MASK_DESCR(_IRQ_HIDDEN),
+};
+
+static const struct irq_bit_descr irqdesc_istates[] = {
+	BIT_MASK_DESCR(IRQS_AUTODETECT),
+	BIT_MASK_DESCR(IRQS_SPURIOUS_DISABLED),
+	BIT_MASK_DESCR(IRQS_POLL_INPROGRESS),
+	BIT_MASK_DESCR(IRQS_ONESHOT),
+	BIT_MASK_DESCR(IRQS_REPLAY),
+	BIT_MASK_DESCR(IRQS_WAITING),
+	BIT_MASK_DESCR(IRQS_PENDING),
+	BIT_MASK_DESCR(IRQS_SUSPENDED),
+	BIT_MASK_DESCR(IRQS_NMI),
+};
+
+
+static int irq_debug_show(struct seq_file *m, void *p)
+{
+	struct irq_desc *desc = m->private;
+	struct irq_data *data;
+
+	raw_spin_lock_irq(&desc->lock);
+	data = irq_desc_get_irq_data(desc);
+	seq_printf(m, "handler:  %ps\n", desc->handle_irq);
+	seq_printf(m, "device:   %s\n", desc->dev_name);
+	seq_printf(m, "status:   0x%08x\n", desc->status_use_accessors);
+	irq_debug_show_bits(m, 0, desc->status_use_accessors, irqdesc_states,
+			    ARRAY_SIZE(irqdesc_states));
+	seq_printf(m, "istate:   0x%08x\n", desc->istate);
+	irq_debug_show_bits(m, 0, desc->istate, irqdesc_istates,
+			    ARRAY_SIZE(irqdesc_istates));
+	seq_printf(m, "ddepth:   %u\n", desc->depth);
+	seq_printf(m, "wdepth:   %u\n", desc->wake_depth);
+	seq_printf(m, "dstate:   0x%08x\n", irqd_get(data));
+	irq_debug_show_bits(m, 0, irqd_get(data), irqdata_states,
+			    ARRAY_SIZE(irqdata_states));
+	seq_printf(m, "node:     %d\n", irq_data_get_node(data));
+	irq_debug_show_masks(m, desc);
+	irq_debug_show_data(m, data, 0);
+	raw_spin_unlock_irq(&desc->lock);
+	return 0;
+}
+
+static int irq_debug_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, irq_debug_show, inode->i_private);
+}
+
+static ssize_t irq_debug_write(struct file *file, const char __user *user_buf,
+			       size_t count, loff_t *ppos)
+{
+	struct irq_desc *desc = file_inode(file)->i_private;
+	char buf[8] = { 0, };
+	size_t size;
+
+	size = min(sizeof(buf) - 1, count);
+	if (copy_from_user(buf, user_buf, size))
+		return -EFAULT;
+
+	if (!strncmp(buf, "trigger", size)) {
+		int err = irq_inject_interrupt(irq_desc_get_irq(desc));
+
+		return err ? err : count;
+	}
+
+	return count;
+}
+
+static const struct file_operations dfs_irq_ops = {
+	.open		= irq_debug_open,
+	.write		= irq_debug_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+void irq_debugfs_copy_devname(int irq, struct device *dev)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	const char *name = dev_name(dev);
+
+	if (name)
+		desc->dev_name = kstrdup(name, GFP_KERNEL);
+}
+
+void irq_add_debugfs_entry(unsigned int irq, struct irq_desc *desc)
+{
+	char name [10];
+
+	if (!irq_dir || !desc || desc->debugfs_file)
+		return;
+
+	sprintf(name, "%d", irq);
+	desc->debugfs_file = debugfs_create_file(name, 0644, irq_dir, desc,
+						 &dfs_irq_ops);
+}
+
+static int __init irq_debugfs_init(void)
+{
+	struct dentry *root_dir;
+	int irq;
+
+	root_dir = debugfs_create_dir("irq", NULL);
+
+	irq_domain_debugfs_init(root_dir);
+
+	irq_dir = debugfs_create_dir("irqs", root_dir);
+
+	irq_lock_sparse();
+	for_each_active_irq(irq)
+		irq_add_debugfs_entry(irq, irq_to_desc(irq));
+	irq_unlock_sparse();
+
+	return 0;
+}
+__initcall(irq_debugfs_init);
diff --git a/kernel/irq/devres.c b/kernel/irq/devres.c
new file mode 100644
index 000000000..f6e5515ee
--- /dev/null
+++ b/kernel/irq/devres.c
@@ -0,0 +1,284 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/gfp.h>
+#include <linux/irq.h>
+
+#include "internals.h"
+
+/*
+ * Device resource management aware IRQ request/free implementation.
+ */
+struct irq_devres {
+	unsigned int irq;
+	void *dev_id;
+};
+
+static void devm_irq_release(struct device *dev, void *res)
+{
+	struct irq_devres *this = res;
+
+	free_irq(this->irq, this->dev_id);
+}
+
+static int devm_irq_match(struct device *dev, void *res, void *data)
+{
+	struct irq_devres *this = res, *match = data;
+
+	return this->irq == match->irq && this->dev_id == match->dev_id;
+}
+
+/**
+ *	devm_request_threaded_irq - allocate an interrupt line for a managed device
+ *	@dev: device to request interrupt for
+ *	@irq: Interrupt line to allocate
+ *	@handler: Function to be called when the IRQ occurs
+ *	@thread_fn: function to be called in a threaded interrupt context. NULL
+ *		    for devices which handle everything in @handler
+ *	@irqflags: Interrupt type flags
+ *	@devname: An ascii name for the claiming device, dev_name(dev) if NULL
+ *	@dev_id: A cookie passed back to the handler function
+ *
+ *	Except for the extra @dev argument, this function takes the
+ *	same arguments and performs the same function as
+ *	request_threaded_irq().  IRQs requested with this function will be
+ *	automatically freed on driver detach.
+ *
+ *	If an IRQ allocated with this function needs to be freed
+ *	separately, devm_free_irq() must be used.
+ */
+int devm_request_threaded_irq(struct device *dev, unsigned int irq,
+			      irq_handler_t handler, irq_handler_t thread_fn,
+			      unsigned long irqflags, const char *devname,
+			      void *dev_id)
+{
+	struct irq_devres *dr;
+	int rc;
+
+	dr = devres_alloc(devm_irq_release, sizeof(struct irq_devres),
+			  GFP_KERNEL);
+	if (!dr)
+		return -ENOMEM;
+
+	if (!devname)
+		devname = dev_name(dev);
+
+	rc = request_threaded_irq(irq, handler, thread_fn, irqflags, devname,
+				  dev_id);
+	if (rc) {
+		devres_free(dr);
+		return rc;
+	}
+
+	dr->irq = irq;
+	dr->dev_id = dev_id;
+	devres_add(dev, dr);
+
+	return 0;
+}
+EXPORT_SYMBOL(devm_request_threaded_irq);
+
+/**
+ *	devm_request_any_context_irq - allocate an interrupt line for a managed device
+ *	@dev: device to request interrupt for
+ *	@irq: Interrupt line to allocate
+ *	@handler: Function to be called when the IRQ occurs
+ *	@irqflags: Interrupt type flags
+ *	@devname: An ascii name for the claiming device, dev_name(dev) if NULL
+ *	@dev_id: A cookie passed back to the handler function
+ *
+ *	Except for the extra @dev argument, this function takes the
+ *	same arguments and performs the same function as
+ *	request_any_context_irq().  IRQs requested with this function will be
+ *	automatically freed on driver detach.
+ *
+ *	If an IRQ allocated with this function needs to be freed
+ *	separately, devm_free_irq() must be used.
+ */
+int devm_request_any_context_irq(struct device *dev, unsigned int irq,
+			      irq_handler_t handler, unsigned long irqflags,
+			      const char *devname, void *dev_id)
+{
+	struct irq_devres *dr;
+	int rc;
+
+	dr = devres_alloc(devm_irq_release, sizeof(struct irq_devres),
+			  GFP_KERNEL);
+	if (!dr)
+		return -ENOMEM;
+
+	if (!devname)
+		devname = dev_name(dev);
+
+	rc = request_any_context_irq(irq, handler, irqflags, devname, dev_id);
+	if (rc < 0) {
+		devres_free(dr);
+		return rc;
+	}
+
+	dr->irq = irq;
+	dr->dev_id = dev_id;
+	devres_add(dev, dr);
+
+	return rc;
+}
+EXPORT_SYMBOL(devm_request_any_context_irq);
+
+/**
+ *	devm_free_irq - free an interrupt
+ *	@dev: device to free interrupt for
+ *	@irq: Interrupt line to free
+ *	@dev_id: Device identity to free
+ *
+ *	Except for the extra @dev argument, this function takes the
+ *	same arguments and performs the same function as free_irq().
+ *	This function instead of free_irq() should be used to manually
+ *	free IRQs allocated with devm_request_irq().
+ */
+void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id)
+{
+	struct irq_devres match_data = { irq, dev_id };
+
+	WARN_ON(devres_destroy(dev, devm_irq_release, devm_irq_match,
+			       &match_data));
+	free_irq(irq, dev_id);
+}
+EXPORT_SYMBOL(devm_free_irq);
+
+struct irq_desc_devres {
+	unsigned int from;
+	unsigned int cnt;
+};
+
+static void devm_irq_desc_release(struct device *dev, void *res)
+{
+	struct irq_desc_devres *this = res;
+
+	irq_free_descs(this->from, this->cnt);
+}
+
+/**
+ * __devm_irq_alloc_descs - Allocate and initialize a range of irq descriptors
+ *			    for a managed device
+ * @dev:	Device to allocate the descriptors for
+ * @irq:	Allocate for specific irq number if irq >= 0
+ * @from:	Start the search from this irq number
+ * @cnt:	Number of consecutive irqs to allocate
+ * @node:	Preferred node on which the irq descriptor should be allocated
+ * @owner:	Owning module (can be NULL)
+ * @affinity:	Optional pointer to an irq_affinity_desc array of size @cnt
+ *		which hints where the irq descriptors should be allocated
+ *		and which default affinities to use
+ *
+ * Returns the first irq number or error code.
+ *
+ * Note: Use the provided wrappers (devm_irq_alloc_desc*) for simplicity.
+ */
+int __devm_irq_alloc_descs(struct device *dev, int irq, unsigned int from,
+			   unsigned int cnt, int node, struct module *owner,
+			   const struct irq_affinity_desc *affinity)
+{
+	struct irq_desc_devres *dr;
+	int base;
+
+	dr = devres_alloc(devm_irq_desc_release, sizeof(*dr), GFP_KERNEL);
+	if (!dr)
+		return -ENOMEM;
+
+	base = __irq_alloc_descs(irq, from, cnt, node, owner, affinity);
+	if (base < 0) {
+		devres_free(dr);
+		return base;
+	}
+
+	dr->from = base;
+	dr->cnt = cnt;
+	devres_add(dev, dr);
+
+	return base;
+}
+EXPORT_SYMBOL_GPL(__devm_irq_alloc_descs);
+
+#ifdef CONFIG_GENERIC_IRQ_CHIP
+/**
+ * devm_irq_alloc_generic_chip - Allocate and initialize a generic chip
+ *                               for a managed device
+ * @dev:	Device to allocate the generic chip for
+ * @name:	Name of the irq chip
+ * @num_ct:	Number of irq_chip_type instances associated with this
+ * @irq_base:	Interrupt base nr for this chip
+ * @reg_base:	Register base address (virtual)
+ * @handler:	Default flow handler associated with this chip
+ *
+ * Returns an initialized irq_chip_generic structure. The chip defaults
+ * to the primary (index 0) irq_chip_type and @handler
+ */
+struct irq_chip_generic *
+devm_irq_alloc_generic_chip(struct device *dev, const char *name, int num_ct,
+			    unsigned int irq_base, void __iomem *reg_base,
+			    irq_flow_handler_t handler)
+{
+	struct irq_chip_generic *gc;
+
+	gc = devm_kzalloc(dev, struct_size(gc, chip_types, num_ct), GFP_KERNEL);
+	if (gc)
+		irq_init_generic_chip(gc, name, num_ct,
+				      irq_base, reg_base, handler);
+
+	return gc;
+}
+EXPORT_SYMBOL_GPL(devm_irq_alloc_generic_chip);
+
+struct irq_generic_chip_devres {
+	struct irq_chip_generic *gc;
+	u32 msk;
+	unsigned int clr;
+	unsigned int set;
+};
+
+static void devm_irq_remove_generic_chip(struct device *dev, void *res)
+{
+	struct irq_generic_chip_devres *this = res;
+
+	irq_remove_generic_chip(this->gc, this->msk, this->clr, this->set);
+}
+
+/**
+ * devm_irq_setup_generic_chip - Setup a range of interrupts with a generic
+ *                               chip for a managed device
+ *
+ * @dev:	Device to setup the generic chip for
+ * @gc:		Generic irq chip holding all data
+ * @msk:	Bitmask holding the irqs to initialize relative to gc->irq_base
+ * @flags:	Flags for initialization
+ * @clr:	IRQ_* bits to clear
+ * @set:	IRQ_* bits to set
+ *
+ * Set up max. 32 interrupts starting from gc->irq_base. Note, this
+ * initializes all interrupts to the primary irq_chip_type and its
+ * associated handler.
+ */
+int devm_irq_setup_generic_chip(struct device *dev, struct irq_chip_generic *gc,
+				u32 msk, enum irq_gc_flags flags,
+				unsigned int clr, unsigned int set)
+{
+	struct irq_generic_chip_devres *dr;
+
+	dr = devres_alloc(devm_irq_remove_generic_chip,
+			  sizeof(*dr), GFP_KERNEL);
+	if (!dr)
+		return -ENOMEM;
+
+	irq_setup_generic_chip(gc, msk, flags, clr, set);
+
+	dr->gc = gc;
+	dr->msk = msk;
+	dr->clr = clr;
+	dr->set = set;
+	devres_add(dev, dr);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_irq_setup_generic_chip);
+#endif /* CONFIG_GENERIC_IRQ_CHIP */
diff --git a/kernel/irq/dummychip.c b/kernel/irq/dummychip.c
new file mode 100644
index 000000000..7fe6cffe7
--- /dev/null
+++ b/kernel/irq/dummychip.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
+ * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
+ *
+ * This file contains the dummy interrupt chip implementation
+ */
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/export.h>
+
+#include "internals.h"
+
+/*
+ * What should we do if we get a hw irq event on an illegal vector?
+ * Each architecture has to answer this themselves.
+ */
+static void ack_bad(struct irq_data *data)
+{
+	struct irq_desc *desc = irq_data_to_desc(data);
+
+	print_irq_desc(data->irq, desc);
+	ack_bad_irq(data->irq);
+}
+
+/*
+ * NOP functions
+ */
+static void noop(struct irq_data *data) { }
+
+static unsigned int noop_ret(struct irq_data *data)
+{
+	return 0;
+}
+
+/*
+ * Generic no controller implementation
+ */
+struct irq_chip no_irq_chip = {
+	.name		= "none",
+	.irq_startup	= noop_ret,
+	.irq_shutdown	= noop,
+	.irq_enable	= noop,
+	.irq_disable	= noop,
+	.irq_ack	= ack_bad,
+	.flags		= IRQCHIP_SKIP_SET_WAKE,
+};
+
+/*
+ * Generic dummy implementation which can be used for
+ * real dumb interrupt sources
+ */
+struct irq_chip dummy_irq_chip = {
+	.name		= "dummy",
+	.irq_startup	= noop_ret,
+	.irq_shutdown	= noop,
+	.irq_enable	= noop,
+	.irq_disable	= noop,
+	.irq_ack	= noop,
+	.irq_mask	= noop,
+	.irq_unmask	= noop,
+	.flags		= IRQCHIP_SKIP_SET_WAKE,
+};
+EXPORT_SYMBOL_GPL(dummy_irq_chip);
diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c
new file mode 100644
index 000000000..5a452b94b
--- /dev/null
+++ b/kernel/irq/generic-chip.c
@@ -0,0 +1,668 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Library implementing the most common irq chip callback functions
+ *
+ * Copyright (C) 2011, Thomas Gleixner
+ */
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/irqdomain.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+#include <linux/syscore_ops.h>
+
+#include "internals.h"
+
+static LIST_HEAD(gc_list);
+static DEFINE_RAW_SPINLOCK(gc_lock);
+
+/**
+ * irq_gc_noop - NOOP function
+ * @d: irq_data
+ */
+void irq_gc_noop(struct irq_data *d)
+{
+}
+EXPORT_SYMBOL_GPL(irq_gc_noop);
+
+/**
+ * irq_gc_mask_disable_reg - Mask chip via disable register
+ * @d: irq_data
+ *
+ * Chip has separate enable/disable registers instead of a single mask
+ * register.
+ */
+void irq_gc_mask_disable_reg(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
+	u32 mask = d->mask;
+
+	irq_gc_lock(gc);
+	irq_reg_writel(gc, mask, ct->regs.disable);
+	*ct->mask_cache &= ~mask;
+	irq_gc_unlock(gc);
+}
+EXPORT_SYMBOL_GPL(irq_gc_mask_disable_reg);
+
+/**
+ * irq_gc_mask_set_bit - Mask chip via setting bit in mask register
+ * @d: irq_data
+ *
+ * Chip has a single mask register. Values of this register are cached
+ * and protected by gc->lock
+ */
+void irq_gc_mask_set_bit(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
+	u32 mask = d->mask;
+
+	irq_gc_lock(gc);
+	*ct->mask_cache |= mask;
+	irq_reg_writel(gc, *ct->mask_cache, ct->regs.mask);
+	irq_gc_unlock(gc);
+}
+EXPORT_SYMBOL_GPL(irq_gc_mask_set_bit);
+
+/**
+ * irq_gc_mask_clr_bit - Mask chip via clearing bit in mask register
+ * @d: irq_data
+ *
+ * Chip has a single mask register. Values of this register are cached
+ * and protected by gc->lock
+ */
+void irq_gc_mask_clr_bit(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
+	u32 mask = d->mask;
+
+	irq_gc_lock(gc);
+	*ct->mask_cache &= ~mask;
+	irq_reg_writel(gc, *ct->mask_cache, ct->regs.mask);
+	irq_gc_unlock(gc);
+}
+EXPORT_SYMBOL_GPL(irq_gc_mask_clr_bit);
+
+/**
+ * irq_gc_unmask_enable_reg - Unmask chip via enable register
+ * @d: irq_data
+ *
+ * Chip has separate enable/disable registers instead of a single mask
+ * register.
+ */
+void irq_gc_unmask_enable_reg(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
+	u32 mask = d->mask;
+
+	irq_gc_lock(gc);
+	irq_reg_writel(gc, mask, ct->regs.enable);
+	*ct->mask_cache |= mask;
+	irq_gc_unlock(gc);
+}
+EXPORT_SYMBOL_GPL(irq_gc_unmask_enable_reg);
+
+/**
+ * irq_gc_ack_set_bit - Ack pending interrupt via setting bit
+ * @d: irq_data
+ */
+void irq_gc_ack_set_bit(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
+	u32 mask = d->mask;
+
+	irq_gc_lock(gc);
+	irq_reg_writel(gc, mask, ct->regs.ack);
+	irq_gc_unlock(gc);
+}
+EXPORT_SYMBOL_GPL(irq_gc_ack_set_bit);
+
+/**
+ * irq_gc_ack_clr_bit - Ack pending interrupt via clearing bit
+ * @d: irq_data
+ */
+void irq_gc_ack_clr_bit(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
+	u32 mask = ~d->mask;
+
+	irq_gc_lock(gc);
+	irq_reg_writel(gc, mask, ct->regs.ack);
+	irq_gc_unlock(gc);
+}
+
+/**
+ * irq_gc_mask_disable_and_ack_set - Mask and ack pending interrupt
+ * @d: irq_data
+ *
+ * This generic implementation of the irq_mask_ack method is for chips
+ * with separate enable/disable registers instead of a single mask
+ * register and where a pending interrupt is acknowledged by setting a
+ * bit.
+ *
+ * Note: This is the only permutation currently used.  Similar generic
+ * functions should be added here if other permutations are required.
+ */
+void irq_gc_mask_disable_and_ack_set(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
+	u32 mask = d->mask;
+
+	irq_gc_lock(gc);
+	irq_reg_writel(gc, mask, ct->regs.disable);
+	*ct->mask_cache &= ~mask;
+	irq_reg_writel(gc, mask, ct->regs.ack);
+	irq_gc_unlock(gc);
+}
+
+/**
+ * irq_gc_eoi - EOI interrupt
+ * @d: irq_data
+ */
+void irq_gc_eoi(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
+	u32 mask = d->mask;
+
+	irq_gc_lock(gc);
+	irq_reg_writel(gc, mask, ct->regs.eoi);
+	irq_gc_unlock(gc);
+}
+
+/**
+ * irq_gc_set_wake - Set/clr wake bit for an interrupt
+ * @d:  irq_data
+ * @on: Indicates whether the wake bit should be set or cleared
+ *
+ * For chips where the wake from suspend functionality is not
+ * configured in a separate register and the wakeup active state is
+ * just stored in a bitmask.
+ */
+int irq_gc_set_wake(struct irq_data *d, unsigned int on)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	u32 mask = d->mask;
+
+	if (!(mask & gc->wake_enabled))
+		return -EINVAL;
+
+	irq_gc_lock(gc);
+	if (on)
+		gc->wake_active |= mask;
+	else
+		gc->wake_active &= ~mask;
+	irq_gc_unlock(gc);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_gc_set_wake);
+
+static u32 irq_readl_be(void __iomem *addr)
+{
+	return ioread32be(addr);
+}
+
+static void irq_writel_be(u32 val, void __iomem *addr)
+{
+	iowrite32be(val, addr);
+}
+
+void irq_init_generic_chip(struct irq_chip_generic *gc, const char *name,
+			   int num_ct, unsigned int irq_base,
+			   void __iomem *reg_base, irq_flow_handler_t handler)
+{
+	raw_spin_lock_init(&gc->lock);
+	gc->num_ct = num_ct;
+	gc->irq_base = irq_base;
+	gc->reg_base = reg_base;
+	gc->chip_types->chip.name = name;
+	gc->chip_types->handler = handler;
+}
+
+/**
+ * irq_alloc_generic_chip - Allocate a generic chip and initialize it
+ * @name:	Name of the irq chip
+ * @num_ct:	Number of irq_chip_type instances associated with this
+ * @irq_base:	Interrupt base nr for this chip
+ * @reg_base:	Register base address (virtual)
+ * @handler:	Default flow handler associated with this chip
+ *
+ * Returns an initialized irq_chip_generic structure. The chip defaults
+ * to the primary (index 0) irq_chip_type and @handler
+ */
+struct irq_chip_generic *
+irq_alloc_generic_chip(const char *name, int num_ct, unsigned int irq_base,
+		       void __iomem *reg_base, irq_flow_handler_t handler)
+{
+	struct irq_chip_generic *gc;
+
+	gc = kzalloc(struct_size(gc, chip_types, num_ct), GFP_KERNEL);
+	if (gc) {
+		irq_init_generic_chip(gc, name, num_ct, irq_base, reg_base,
+				      handler);
+	}
+	return gc;
+}
+EXPORT_SYMBOL_GPL(irq_alloc_generic_chip);
+
+static void
+irq_gc_init_mask_cache(struct irq_chip_generic *gc, enum irq_gc_flags flags)
+{
+	struct irq_chip_type *ct = gc->chip_types;
+	u32 *mskptr = &gc->mask_cache, mskreg = ct->regs.mask;
+	int i;
+
+	for (i = 0; i < gc->num_ct; i++) {
+		if (flags & IRQ_GC_MASK_CACHE_PER_TYPE) {
+			mskptr = &ct[i].mask_cache_priv;
+			mskreg = ct[i].regs.mask;
+		}
+		ct[i].mask_cache = mskptr;
+		if (flags & IRQ_GC_INIT_MASK_CACHE)
+			*mskptr = irq_reg_readl(gc, mskreg);
+	}
+}
+
+/**
+ * __irq_alloc_domain_generic_chips - Allocate generic chips for an irq domain
+ * @d:			irq domain for which to allocate chips
+ * @irqs_per_chip:	Number of interrupts each chip handles (max 32)
+ * @num_ct:		Number of irq_chip_type instances associated with this
+ * @name:		Name of the irq chip
+ * @handler:		Default flow handler associated with these chips
+ * @clr:		IRQ_* bits to clear in the mapping function
+ * @set:		IRQ_* bits to set in the mapping function
+ * @gcflags:		Generic chip specific setup flags
+ */
+int __irq_alloc_domain_generic_chips(struct irq_domain *d, int irqs_per_chip,
+				     int num_ct, const char *name,
+				     irq_flow_handler_t handler,
+				     unsigned int clr, unsigned int set,
+				     enum irq_gc_flags gcflags)
+{
+	struct irq_domain_chip_generic *dgc;
+	struct irq_chip_generic *gc;
+	unsigned long flags;
+	int numchips, i;
+	size_t dgc_sz;
+	size_t gc_sz;
+	size_t sz;
+	void *tmp;
+
+	if (d->gc)
+		return -EBUSY;
+
+	numchips = DIV_ROUND_UP(d->revmap_size, irqs_per_chip);
+	if (!numchips)
+		return -EINVAL;
+
+	/* Allocate a pointer, generic chip and chiptypes for each chip */
+	gc_sz = struct_size(gc, chip_types, num_ct);
+	dgc_sz = struct_size(dgc, gc, numchips);
+	sz = dgc_sz + numchips * gc_sz;
+
+	tmp = dgc = kzalloc(sz, GFP_KERNEL);
+	if (!dgc)
+		return -ENOMEM;
+	dgc->irqs_per_chip = irqs_per_chip;
+	dgc->num_chips = numchips;
+	dgc->irq_flags_to_set = set;
+	dgc->irq_flags_to_clear = clr;
+	dgc->gc_flags = gcflags;
+	d->gc = dgc;
+
+	/* Calc pointer to the first generic chip */
+	tmp += dgc_sz;
+	for (i = 0; i < numchips; i++) {
+		/* Store the pointer to the generic chip */
+		dgc->gc[i] = gc = tmp;
+		irq_init_generic_chip(gc, name, num_ct, i * irqs_per_chip,
+				      NULL, handler);
+
+		gc->domain = d;
+		if (gcflags & IRQ_GC_BE_IO) {
+			gc->reg_readl = &irq_readl_be;
+			gc->reg_writel = &irq_writel_be;
+		}
+
+		raw_spin_lock_irqsave(&gc_lock, flags);
+		list_add_tail(&gc->list, &gc_list);
+		raw_spin_unlock_irqrestore(&gc_lock, flags);
+		/* Calc pointer to the next generic chip */
+		tmp += gc_sz;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__irq_alloc_domain_generic_chips);
+
+static struct irq_chip_generic *
+__irq_get_domain_generic_chip(struct irq_domain *d, unsigned int hw_irq)
+{
+	struct irq_domain_chip_generic *dgc = d->gc;
+	int idx;
+
+	if (!dgc)
+		return ERR_PTR(-ENODEV);
+	idx = hw_irq / dgc->irqs_per_chip;
+	if (idx >= dgc->num_chips)
+		return ERR_PTR(-EINVAL);
+	return dgc->gc[idx];
+}
+
+/**
+ * irq_get_domain_generic_chip - Get a pointer to the generic chip of a hw_irq
+ * @d:			irq domain pointer
+ * @hw_irq:		Hardware interrupt number
+ */
+struct irq_chip_generic *
+irq_get_domain_generic_chip(struct irq_domain *d, unsigned int hw_irq)
+{
+	struct irq_chip_generic *gc = __irq_get_domain_generic_chip(d, hw_irq);
+
+	return !IS_ERR(gc) ? gc : NULL;
+}
+EXPORT_SYMBOL_GPL(irq_get_domain_generic_chip);
+
+/*
+ * Separate lockdep classes for interrupt chip which can nest irq_desc
+ * lock and request mutex.
+ */
+static struct lock_class_key irq_nested_lock_class;
+static struct lock_class_key irq_nested_request_class;
+
+/*
+ * irq_map_generic_chip - Map a generic chip for an irq domain
+ */
+int irq_map_generic_chip(struct irq_domain *d, unsigned int virq,
+			 irq_hw_number_t hw_irq)
+{
+	struct irq_data *data = irq_domain_get_irq_data(d, virq);
+	struct irq_domain_chip_generic *dgc = d->gc;
+	struct irq_chip_generic *gc;
+	struct irq_chip_type *ct;
+	struct irq_chip *chip;
+	unsigned long flags;
+	int idx;
+
+	gc = __irq_get_domain_generic_chip(d, hw_irq);
+	if (IS_ERR(gc))
+		return PTR_ERR(gc);
+
+	idx = hw_irq % dgc->irqs_per_chip;
+
+	if (test_bit(idx, &gc->unused))
+		return -ENOTSUPP;
+
+	if (test_bit(idx, &gc->installed))
+		return -EBUSY;
+
+	ct = gc->chip_types;
+	chip = &ct->chip;
+
+	/* We only init the cache for the first mapping of a generic chip */
+	if (!gc->installed) {
+		raw_spin_lock_irqsave(&gc->lock, flags);
+		irq_gc_init_mask_cache(gc, dgc->gc_flags);
+		raw_spin_unlock_irqrestore(&gc->lock, flags);
+	}
+
+	/* Mark the interrupt as installed */
+	set_bit(idx, &gc->installed);
+
+	if (dgc->gc_flags & IRQ_GC_INIT_NESTED_LOCK)
+		irq_set_lockdep_class(virq, &irq_nested_lock_class,
+				      &irq_nested_request_class);
+
+	if (chip->irq_calc_mask)
+		chip->irq_calc_mask(data);
+	else
+		data->mask = 1 << idx;
+
+	irq_domain_set_info(d, virq, hw_irq, chip, gc, ct->handler, NULL, NULL);
+	irq_modify_status(virq, dgc->irq_flags_to_clear, dgc->irq_flags_to_set);
+	return 0;
+}
+
+void irq_unmap_generic_chip(struct irq_domain *d, unsigned int virq)
+{
+	struct irq_data *data = irq_domain_get_irq_data(d, virq);
+	struct irq_domain_chip_generic *dgc = d->gc;
+	unsigned int hw_irq = data->hwirq;
+	struct irq_chip_generic *gc;
+	int irq_idx;
+
+	gc = irq_get_domain_generic_chip(d, hw_irq);
+	if (!gc)
+		return;
+
+	irq_idx = hw_irq % dgc->irqs_per_chip;
+
+	clear_bit(irq_idx, &gc->installed);
+	irq_domain_set_info(d, virq, hw_irq, &no_irq_chip, NULL, NULL, NULL,
+			    NULL);
+
+}
+
+const struct irq_domain_ops irq_generic_chip_ops = {
+	.map	= irq_map_generic_chip,
+	.unmap  = irq_unmap_generic_chip,
+	.xlate	= irq_domain_xlate_onetwocell,
+};
+EXPORT_SYMBOL_GPL(irq_generic_chip_ops);
+
+/**
+ * irq_setup_generic_chip - Setup a range of interrupts with a generic chip
+ * @gc:		Generic irq chip holding all data
+ * @msk:	Bitmask holding the irqs to initialize relative to gc->irq_base
+ * @flags:	Flags for initialization
+ * @clr:	IRQ_* bits to clear
+ * @set:	IRQ_* bits to set
+ *
+ * Set up max. 32 interrupts starting from gc->irq_base. Note, this
+ * initializes all interrupts to the primary irq_chip_type and its
+ * associated handler.
+ */
+void irq_setup_generic_chip(struct irq_chip_generic *gc, u32 msk,
+			    enum irq_gc_flags flags, unsigned int clr,
+			    unsigned int set)
+{
+	struct irq_chip_type *ct = gc->chip_types;
+	struct irq_chip *chip = &ct->chip;
+	unsigned int i;
+
+	raw_spin_lock(&gc_lock);
+	list_add_tail(&gc->list, &gc_list);
+	raw_spin_unlock(&gc_lock);
+
+	irq_gc_init_mask_cache(gc, flags);
+
+	for (i = gc->irq_base; msk; msk >>= 1, i++) {
+		if (!(msk & 0x01))
+			continue;
+
+		if (flags & IRQ_GC_INIT_NESTED_LOCK)
+			irq_set_lockdep_class(i, &irq_nested_lock_class,
+					      &irq_nested_request_class);
+
+		if (!(flags & IRQ_GC_NO_MASK)) {
+			struct irq_data *d = irq_get_irq_data(i);
+
+			if (chip->irq_calc_mask)
+				chip->irq_calc_mask(d);
+			else
+				d->mask = 1 << (i - gc->irq_base);
+		}
+		irq_set_chip_and_handler(i, chip, ct->handler);
+		irq_set_chip_data(i, gc);
+		irq_modify_status(i, clr, set);
+	}
+	gc->irq_cnt = i - gc->irq_base;
+}
+EXPORT_SYMBOL_GPL(irq_setup_generic_chip);
+
+/**
+ * irq_setup_alt_chip - Switch to alternative chip
+ * @d:		irq_data for this interrupt
+ * @type:	Flow type to be initialized
+ *
+ * Only to be called from chip->irq_set_type() callbacks.
+ */
+int irq_setup_alt_chip(struct irq_data *d, unsigned int type)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = gc->chip_types;
+	unsigned int i;
+
+	for (i = 0; i < gc->num_ct; i++, ct++) {
+		if (ct->type & type) {
+			d->chip = &ct->chip;
+			irq_data_to_desc(d)->handle_irq = ct->handler;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(irq_setup_alt_chip);
+
+/**
+ * irq_remove_generic_chip - Remove a chip
+ * @gc:		Generic irq chip holding all data
+ * @msk:	Bitmask holding the irqs to initialize relative to gc->irq_base
+ * @clr:	IRQ_* bits to clear
+ * @set:	IRQ_* bits to set
+ *
+ * Remove up to 32 interrupts starting from gc->irq_base.
+ */
+void irq_remove_generic_chip(struct irq_chip_generic *gc, u32 msk,
+			     unsigned int clr, unsigned int set)
+{
+	unsigned int i, virq;
+
+	raw_spin_lock(&gc_lock);
+	list_del(&gc->list);
+	raw_spin_unlock(&gc_lock);
+
+	for (i = 0; msk; msk >>= 1, i++) {
+		if (!(msk & 0x01))
+			continue;
+
+		/*
+		 * Interrupt domain based chips store the base hardware
+		 * interrupt number in gc::irq_base. Otherwise gc::irq_base
+		 * contains the base Linux interrupt number.
+		 */
+		if (gc->domain) {
+			virq = irq_find_mapping(gc->domain, gc->irq_base + i);
+			if (!virq)
+				continue;
+		} else {
+			virq = gc->irq_base + i;
+		}
+
+		/* Remove handler first. That will mask the irq line */
+		irq_set_handler(virq, NULL);
+		irq_set_chip(virq, &no_irq_chip);
+		irq_set_chip_data(virq, NULL);
+		irq_modify_status(virq, clr, set);
+	}
+}
+EXPORT_SYMBOL_GPL(irq_remove_generic_chip);
+
+static struct irq_data *irq_gc_get_irq_data(struct irq_chip_generic *gc)
+{
+	unsigned int virq;
+
+	if (!gc->domain)
+		return irq_get_irq_data(gc->irq_base);
+
+	/*
+	 * We don't know which of the irqs has been actually
+	 * installed. Use the first one.
+	 */
+	if (!gc->installed)
+		return NULL;
+
+	virq = irq_find_mapping(gc->domain, gc->irq_base + __ffs(gc->installed));
+	return virq ? irq_get_irq_data(virq) : NULL;
+}
+
+#ifdef CONFIG_PM
+static int irq_gc_suspend(void)
+{
+	struct irq_chip_generic *gc;
+
+	list_for_each_entry(gc, &gc_list, list) {
+		struct irq_chip_type *ct = gc->chip_types;
+
+		if (ct->chip.irq_suspend) {
+			struct irq_data *data = irq_gc_get_irq_data(gc);
+
+			if (data)
+				ct->chip.irq_suspend(data);
+		}
+
+		if (gc->suspend)
+			gc->suspend(gc);
+	}
+	return 0;
+}
+
+static void irq_gc_resume(void)
+{
+	struct irq_chip_generic *gc;
+
+	list_for_each_entry(gc, &gc_list, list) {
+		struct irq_chip_type *ct = gc->chip_types;
+
+		if (gc->resume)
+			gc->resume(gc);
+
+		if (ct->chip.irq_resume) {
+			struct irq_data *data = irq_gc_get_irq_data(gc);
+
+			if (data)
+				ct->chip.irq_resume(data);
+		}
+	}
+}
+#else
+#define irq_gc_suspend NULL
+#define irq_gc_resume NULL
+#endif
+
+static void irq_gc_shutdown(void)
+{
+	struct irq_chip_generic *gc;
+
+	list_for_each_entry(gc, &gc_list, list) {
+		struct irq_chip_type *ct = gc->chip_types;
+
+		if (ct->chip.irq_pm_shutdown) {
+			struct irq_data *data = irq_gc_get_irq_data(gc);
+
+			if (data)
+				ct->chip.irq_pm_shutdown(data);
+		}
+	}
+}
+
+static struct syscore_ops irq_gc_syscore_ops = {
+	.suspend = irq_gc_suspend,
+	.resume = irq_gc_resume,
+	.shutdown = irq_gc_shutdown,
+};
+
+static int __init irq_gc_init_ops(void)
+{
+	register_syscore_ops(&irq_gc_syscore_ops);
+	return 0;
+}
+device_initcall(irq_gc_init_ops);
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
new file mode 100644
index 000000000..9489f93b3
--- /dev/null
+++ b/kernel/irq/handle.c
@@ -0,0 +1,242 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
+ * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
+ *
+ * This file contains the core interrupt handling code. Detailed
+ * information is available in Documentation/core-api/genericirq.rst
+ *
+ */
+
+#include <linux/irq.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+
+#include <asm/irq_regs.h>
+
+#include <trace/events/irq.h>
+
+#include "internals.h"
+
+#ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
+void (*handle_arch_irq)(struct pt_regs *) __ro_after_init;
+#endif
+
+/**
+ * handle_bad_irq - handle spurious and unhandled irqs
+ * @desc:      description of the interrupt
+ *
+ * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
+ */
+void handle_bad_irq(struct irq_desc *desc)
+{
+	unsigned int irq = irq_desc_get_irq(desc);
+
+	print_irq_desc(irq, desc);
+	kstat_incr_irqs_this_cpu(desc);
+	ack_bad_irq(irq);
+}
+EXPORT_SYMBOL_GPL(handle_bad_irq);
+
+/*
+ * Special, empty irq handler:
+ */
+irqreturn_t no_action(int cpl, void *dev_id)
+{
+	return IRQ_NONE;
+}
+EXPORT_SYMBOL_GPL(no_action);
+
+static void warn_no_thread(unsigned int irq, struct irqaction *action)
+{
+	if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
+		return;
+
+	printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
+	       "but no thread function available.", irq, action->name);
+}
+
+void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
+{
+	/*
+	 * In case the thread crashed and was killed we just pretend that
+	 * we handled the interrupt. The hardirq handler has disabled the
+	 * device interrupt, so no irq storm is lurking.
+	 */
+	if (action->thread->flags & PF_EXITING)
+		return;
+
+	/*
+	 * Wake up the handler thread for this action. If the
+	 * RUNTHREAD bit is already set, nothing to do.
+	 */
+	if (test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+		return;
+
+	/*
+	 * It's safe to OR the mask lockless here. We have only two
+	 * places which write to threads_oneshot: This code and the
+	 * irq thread.
+	 *
+	 * This code is the hard irq context and can never run on two
+	 * cpus in parallel. If it ever does we have more serious
+	 * problems than this bitmask.
+	 *
+	 * The irq threads of this irq which clear their "running" bit
+	 * in threads_oneshot are serialized via desc->lock against
+	 * each other and they are serialized against this code by
+	 * IRQS_INPROGRESS.
+	 *
+	 * Hard irq handler:
+	 *
+	 *	spin_lock(desc->lock);
+	 *	desc->state |= IRQS_INPROGRESS;
+	 *	spin_unlock(desc->lock);
+	 *	set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
+	 *	desc->threads_oneshot |= mask;
+	 *	spin_lock(desc->lock);
+	 *	desc->state &= ~IRQS_INPROGRESS;
+	 *	spin_unlock(desc->lock);
+	 *
+	 * irq thread:
+	 *
+	 * again:
+	 *	spin_lock(desc->lock);
+	 *	if (desc->state & IRQS_INPROGRESS) {
+	 *		spin_unlock(desc->lock);
+	 *		while(desc->state & IRQS_INPROGRESS)
+	 *			cpu_relax();
+	 *		goto again;
+	 *	}
+	 *	if (!test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+	 *		desc->threads_oneshot &= ~mask;
+	 *	spin_unlock(desc->lock);
+	 *
+	 * So either the thread waits for us to clear IRQS_INPROGRESS
+	 * or we are waiting in the flow handler for desc->lock to be
+	 * released before we reach this point. The thread also checks
+	 * IRQTF_RUNTHREAD under desc->lock. If set it leaves
+	 * threads_oneshot untouched and runs the thread another time.
+	 */
+	desc->threads_oneshot |= action->thread_mask;
+
+	/*
+	 * We increment the threads_active counter in case we wake up
+	 * the irq thread. The irq thread decrements the counter when
+	 * it returns from the handler or in the exit path and wakes
+	 * up waiters which are stuck in synchronize_irq() when the
+	 * active count becomes zero. synchronize_irq() is serialized
+	 * against this code (hard irq handler) via IRQS_INPROGRESS
+	 * like the finalize_oneshot() code. See comment above.
+	 */
+	atomic_inc(&desc->threads_active);
+
+	wake_up_process(action->thread);
+}
+
+irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc)
+{
+	irqreturn_t retval = IRQ_NONE;
+	unsigned int irq = desc->irq_data.irq;
+	struct irqaction *action;
+
+	record_irq_time(desc);
+
+	for_each_action_of_desc(desc, action) {
+		irqreturn_t res;
+
+		/*
+		 * If this IRQ would be threaded under force_irqthreads, mark it so.
+		 */
+		if (irq_settings_can_thread(desc) &&
+		    !(action->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT)))
+			lockdep_hardirq_threaded();
+
+		trace_irq_handler_entry(irq, action);
+		res = action->handler(irq, action->dev_id);
+		trace_irq_handler_exit(irq, action, res);
+
+		if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pS enabled interrupts\n",
+			      irq, action->handler))
+			local_irq_disable();
+
+		switch (res) {
+		case IRQ_WAKE_THREAD:
+			/*
+			 * Catch drivers which return WAKE_THREAD but
+			 * did not set up a thread function
+			 */
+			if (unlikely(!action->thread_fn)) {
+				warn_no_thread(irq, action);
+				break;
+			}
+
+			__irq_wake_thread(desc, action);
+			break;
+
+		default:
+			break;
+		}
+
+		retval |= res;
+	}
+
+	return retval;
+}
+
+irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
+{
+	irqreturn_t retval;
+
+	retval = __handle_irq_event_percpu(desc);
+
+	add_interrupt_randomness(desc->irq_data.irq);
+
+	if (!irq_settings_no_debug(desc))
+		note_interrupt(desc, retval);
+	return retval;
+}
+
+irqreturn_t handle_irq_event(struct irq_desc *desc)
+{
+	irqreturn_t ret;
+
+	desc->istate &= ~IRQS_PENDING;
+	irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);
+	raw_spin_unlock(&desc->lock);
+
+	ret = handle_irq_event_percpu(desc);
+
+	raw_spin_lock(&desc->lock);
+	irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
+	return ret;
+}
+
+#ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
+int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
+{
+	if (handle_arch_irq)
+		return -EBUSY;
+
+	handle_arch_irq = handle_irq;
+	return 0;
+}
+
+/**
+ * generic_handle_arch_irq - root irq handler for architectures which do no
+ *                           entry accounting themselves
+ * @regs:	Register file coming from the low-level handling code
+ */
+asmlinkage void noinstr generic_handle_arch_irq(struct pt_regs *regs)
+{
+	struct pt_regs *old_regs;
+
+	irq_enter();
+	old_regs = set_irq_regs(regs);
+	handle_arch_irq(regs);
+	set_irq_regs(old_regs);
+	irq_exit();
+}
+#endif
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
new file mode 100644
index 000000000..5fdc0b557
--- /dev/null
+++ b/kernel/irq/internals.h
@@ -0,0 +1,516 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * IRQ subsystem internal functions and variables:
+ *
+ * Do not ever include this file from anything else than
+ * kernel/irq/. Do not even think about using any information outside
+ * of this file for your non core code.
+ */
+#include <linux/irqdesc.h>
+#include <linux/kernel_stat.h>
+#include <linux/pm_runtime.h>
+#include <linux/sched/clock.h>
+
+#ifdef CONFIG_SPARSE_IRQ
+# define IRQ_BITMAP_BITS	(NR_IRQS + 8196)
+#else
+# define IRQ_BITMAP_BITS	NR_IRQS
+#endif
+
+#define istate core_internal_state__do_not_mess_with_it
+
+extern bool noirqdebug;
+
+extern struct irqaction chained_action;
+
+/*
+ * Bits used by threaded handlers:
+ * IRQTF_RUNTHREAD - signals that the interrupt handler thread should run
+ * IRQTF_WARNED    - warning "IRQ_WAKE_THREAD w/o thread_fn" has been printed
+ * IRQTF_AFFINITY  - irq thread is requested to adjust affinity
+ * IRQTF_FORCED_THREAD  - irq action is force threaded
+ * IRQTF_READY     - signals that irq thread is ready
+ */
+enum {
+	IRQTF_RUNTHREAD,
+	IRQTF_WARNED,
+	IRQTF_AFFINITY,
+	IRQTF_FORCED_THREAD,
+	IRQTF_READY,
+};
+
+/*
+ * Bit masks for desc->core_internal_state__do_not_mess_with_it
+ *
+ * IRQS_AUTODETECT		- autodetection in progress
+ * IRQS_SPURIOUS_DISABLED	- was disabled due to spurious interrupt
+ *				  detection
+ * IRQS_POLL_INPROGRESS		- polling in progress
+ * IRQS_ONESHOT			- irq is not unmasked in primary handler
+ * IRQS_REPLAY			- irq is replayed
+ * IRQS_WAITING			- irq is waiting
+ * IRQS_PENDING			- irq is pending and replayed later
+ * IRQS_SUSPENDED		- irq is suspended
+ * IRQS_NMI			- irq line is used to deliver NMIs
+ * IRQS_SYSFS			- descriptor has been added to sysfs
+ */
+enum {
+	IRQS_AUTODETECT		= 0x00000001,
+	IRQS_SPURIOUS_DISABLED	= 0x00000002,
+	IRQS_POLL_INPROGRESS	= 0x00000008,
+	IRQS_ONESHOT		= 0x00000020,
+	IRQS_REPLAY		= 0x00000040,
+	IRQS_WAITING		= 0x00000080,
+	IRQS_PENDING		= 0x00000200,
+	IRQS_SUSPENDED		= 0x00000800,
+	IRQS_TIMINGS		= 0x00001000,
+	IRQS_NMI		= 0x00002000,
+	IRQS_SYSFS		= 0x00004000,
+};
+
+#include "debug.h"
+#include "settings.h"
+
+extern int __irq_set_trigger(struct irq_desc *desc, unsigned long flags);
+extern void __disable_irq(struct irq_desc *desc);
+extern void __enable_irq(struct irq_desc *desc);
+
+#define IRQ_RESEND	true
+#define IRQ_NORESEND	false
+
+#define IRQ_START_FORCE	true
+#define IRQ_START_COND	false
+
+extern int irq_activate(struct irq_desc *desc);
+extern int irq_activate_and_startup(struct irq_desc *desc, bool resend);
+extern int irq_startup(struct irq_desc *desc, bool resend, bool force);
+
+extern void irq_shutdown(struct irq_desc *desc);
+extern void irq_shutdown_and_deactivate(struct irq_desc *desc);
+extern void irq_enable(struct irq_desc *desc);
+extern void irq_disable(struct irq_desc *desc);
+extern void irq_percpu_enable(struct irq_desc *desc, unsigned int cpu);
+extern void irq_percpu_disable(struct irq_desc *desc, unsigned int cpu);
+extern void mask_irq(struct irq_desc *desc);
+extern void unmask_irq(struct irq_desc *desc);
+extern void unmask_threaded_irq(struct irq_desc *desc);
+
+#ifdef CONFIG_SPARSE_IRQ
+static inline void irq_mark_irq(unsigned int irq) { }
+#else
+extern void irq_mark_irq(unsigned int irq);
+#endif
+
+extern int __irq_get_irqchip_state(struct irq_data *data,
+				   enum irqchip_irq_state which,
+				   bool *state);
+
+extern void init_kstat_irqs(struct irq_desc *desc, int node, int nr);
+
+irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc);
+irqreturn_t handle_irq_event_percpu(struct irq_desc *desc);
+irqreturn_t handle_irq_event(struct irq_desc *desc);
+
+/* Resending of interrupts :*/
+int check_irq_resend(struct irq_desc *desc, bool inject);
+bool irq_wait_for_poll(struct irq_desc *desc);
+void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action);
+
+#ifdef CONFIG_PROC_FS
+extern void register_irq_proc(unsigned int irq, struct irq_desc *desc);
+extern void unregister_irq_proc(unsigned int irq, struct irq_desc *desc);
+extern void register_handler_proc(unsigned int irq, struct irqaction *action);
+extern void unregister_handler_proc(unsigned int irq, struct irqaction *action);
+#else
+static inline void register_irq_proc(unsigned int irq, struct irq_desc *desc) { }
+static inline void unregister_irq_proc(unsigned int irq, struct irq_desc *desc) { }
+static inline void register_handler_proc(unsigned int irq,
+					 struct irqaction *action) { }
+static inline void unregister_handler_proc(unsigned int irq,
+					   struct irqaction *action) { }
+#endif
+
+extern bool irq_can_set_affinity_usr(unsigned int irq);
+
+extern void irq_set_thread_affinity(struct irq_desc *desc);
+
+extern int irq_do_set_affinity(struct irq_data *data,
+			       const struct cpumask *dest, bool force);
+
+#ifdef CONFIG_SMP
+extern int irq_setup_affinity(struct irq_desc *desc);
+#else
+static inline int irq_setup_affinity(struct irq_desc *desc) { return 0; }
+#endif
+
+/* Inline functions for support of irq chips on slow busses */
+static inline void chip_bus_lock(struct irq_desc *desc)
+{
+	if (unlikely(desc->irq_data.chip->irq_bus_lock))
+		desc->irq_data.chip->irq_bus_lock(&desc->irq_data);
+}
+
+static inline void chip_bus_sync_unlock(struct irq_desc *desc)
+{
+	if (unlikely(desc->irq_data.chip->irq_bus_sync_unlock))
+		desc->irq_data.chip->irq_bus_sync_unlock(&desc->irq_data);
+}
+
+#define _IRQ_DESC_CHECK		(1 << 0)
+#define _IRQ_DESC_PERCPU	(1 << 1)
+
+#define IRQ_GET_DESC_CHECK_GLOBAL	(_IRQ_DESC_CHECK)
+#define IRQ_GET_DESC_CHECK_PERCPU	(_IRQ_DESC_CHECK | _IRQ_DESC_PERCPU)
+
+#define for_each_action_of_desc(desc, act)			\
+	for (act = desc->action; act; act = act->next)
+
+struct irq_desc *
+__irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus,
+		    unsigned int check);
+void __irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags, bool bus);
+
+static inline struct irq_desc *
+irq_get_desc_buslock(unsigned int irq, unsigned long *flags, unsigned int check)
+{
+	return __irq_get_desc_lock(irq, flags, true, check);
+}
+
+static inline void
+irq_put_desc_busunlock(struct irq_desc *desc, unsigned long flags)
+{
+	__irq_put_desc_unlock(desc, flags, true);
+}
+
+static inline struct irq_desc *
+irq_get_desc_lock(unsigned int irq, unsigned long *flags, unsigned int check)
+{
+	return __irq_get_desc_lock(irq, flags, false, check);
+}
+
+static inline void
+irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags)
+{
+	__irq_put_desc_unlock(desc, flags, false);
+}
+
+#define __irqd_to_state(d) ACCESS_PRIVATE((d)->common, state_use_accessors)
+
+static inline unsigned int irqd_get(struct irq_data *d)
+{
+	return __irqd_to_state(d);
+}
+
+/*
+ * Manipulation functions for irq_data.state
+ */
+static inline void irqd_set_move_pending(struct irq_data *d)
+{
+	__irqd_to_state(d) |= IRQD_SETAFFINITY_PENDING;
+}
+
+static inline void irqd_clr_move_pending(struct irq_data *d)
+{
+	__irqd_to_state(d) &= ~IRQD_SETAFFINITY_PENDING;
+}
+
+static inline void irqd_set_managed_shutdown(struct irq_data *d)
+{
+	__irqd_to_state(d) |= IRQD_MANAGED_SHUTDOWN;
+}
+
+static inline void irqd_clr_managed_shutdown(struct irq_data *d)
+{
+	__irqd_to_state(d) &= ~IRQD_MANAGED_SHUTDOWN;
+}
+
+static inline void irqd_clear(struct irq_data *d, unsigned int mask)
+{
+	__irqd_to_state(d) &= ~mask;
+}
+
+static inline void irqd_set(struct irq_data *d, unsigned int mask)
+{
+	__irqd_to_state(d) |= mask;
+}
+
+static inline bool irqd_has_set(struct irq_data *d, unsigned int mask)
+{
+	return __irqd_to_state(d) & mask;
+}
+
+static inline void irq_state_set_disabled(struct irq_desc *desc)
+{
+	irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED);
+}
+
+static inline void irq_state_set_masked(struct irq_desc *desc)
+{
+	irqd_set(&desc->irq_data, IRQD_IRQ_MASKED);
+}
+
+#undef __irqd_to_state
+
+static inline void __kstat_incr_irqs_this_cpu(struct irq_desc *desc)
+{
+	__this_cpu_inc(*desc->kstat_irqs);
+	__this_cpu_inc(kstat.irqs_sum);
+}
+
+static inline void kstat_incr_irqs_this_cpu(struct irq_desc *desc)
+{
+	__kstat_incr_irqs_this_cpu(desc);
+	desc->tot_count++;
+}
+
+static inline int irq_desc_get_node(struct irq_desc *desc)
+{
+	return irq_common_data_get_node(&desc->irq_common_data);
+}
+
+static inline int irq_desc_is_chained(struct irq_desc *desc)
+{
+	return (desc->action && desc->action == &chained_action);
+}
+
+#ifdef CONFIG_PM_SLEEP
+bool irq_pm_check_wakeup(struct irq_desc *desc);
+void irq_pm_install_action(struct irq_desc *desc, struct irqaction *action);
+void irq_pm_remove_action(struct irq_desc *desc, struct irqaction *action);
+#else
+static inline bool irq_pm_check_wakeup(struct irq_desc *desc) { return false; }
+static inline void
+irq_pm_install_action(struct irq_desc *desc, struct irqaction *action) { }
+static inline void
+irq_pm_remove_action(struct irq_desc *desc, struct irqaction *action) { }
+#endif
+
+#ifdef CONFIG_IRQ_TIMINGS
+
+#define IRQ_TIMINGS_SHIFT	5
+#define IRQ_TIMINGS_SIZE	(1 << IRQ_TIMINGS_SHIFT)
+#define IRQ_TIMINGS_MASK	(IRQ_TIMINGS_SIZE - 1)
+
+/**
+ * struct irq_timings - irq timings storing structure
+ * @values: a circular buffer of u64 encoded <timestamp,irq> values
+ * @count: the number of elements in the array
+ */
+struct irq_timings {
+	u64	values[IRQ_TIMINGS_SIZE];
+	int	count;
+};
+
+DECLARE_PER_CPU(struct irq_timings, irq_timings);
+
+extern void irq_timings_free(int irq);
+extern int irq_timings_alloc(int irq);
+
+static inline void irq_remove_timings(struct irq_desc *desc)
+{
+	desc->istate &= ~IRQS_TIMINGS;
+
+	irq_timings_free(irq_desc_get_irq(desc));
+}
+
+static inline void irq_setup_timings(struct irq_desc *desc, struct irqaction *act)
+{
+	int irq = irq_desc_get_irq(desc);
+	int ret;
+
+	/*
+	 * We don't need the measurement because the idle code already
+	 * knows the next expiry event.
+	 */
+	if (act->flags & __IRQF_TIMER)
+		return;
+
+	/*
+	 * In case the timing allocation fails, we just want to warn,
+	 * not fail, so letting the system boot anyway.
+	 */
+	ret = irq_timings_alloc(irq);
+	if (ret) {
+		pr_warn("Failed to allocate irq timing stats for irq%d (%d)",
+			irq, ret);
+		return;
+	}
+
+	desc->istate |= IRQS_TIMINGS;
+}
+
+extern void irq_timings_enable(void);
+extern void irq_timings_disable(void);
+
+DECLARE_STATIC_KEY_FALSE(irq_timing_enabled);
+
+/*
+ * The interrupt number and the timestamp are encoded into a single
+ * u64 variable to optimize the size.
+ * 48 bit time stamp and 16 bit IRQ number is way sufficient.
+ *  Who cares an IRQ after 78 hours of idle time?
+ */
+static inline u64 irq_timing_encode(u64 timestamp, int irq)
+{
+	return (timestamp << 16) | irq;
+}
+
+static inline int irq_timing_decode(u64 value, u64 *timestamp)
+{
+	*timestamp = value >> 16;
+	return value & U16_MAX;
+}
+
+static __always_inline void irq_timings_push(u64 ts, int irq)
+{
+	struct irq_timings *timings = this_cpu_ptr(&irq_timings);
+
+	timings->values[timings->count & IRQ_TIMINGS_MASK] =
+		irq_timing_encode(ts, irq);
+
+	timings->count++;
+}
+
+/*
+ * The function record_irq_time is only called in one place in the
+ * interrupts handler. We want this function always inline so the code
+ * inside is embedded in the function and the static key branching
+ * code can act at the higher level. Without the explicit
+ * __always_inline we can end up with a function call and a small
+ * overhead in the hotpath for nothing.
+ */
+static __always_inline void record_irq_time(struct irq_desc *desc)
+{
+	if (!static_branch_likely(&irq_timing_enabled))
+		return;
+
+	if (desc->istate & IRQS_TIMINGS)
+		irq_timings_push(local_clock(), irq_desc_get_irq(desc));
+}
+#else
+static inline void irq_remove_timings(struct irq_desc *desc) {}
+static inline void irq_setup_timings(struct irq_desc *desc,
+				     struct irqaction *act) {};
+static inline void record_irq_time(struct irq_desc *desc) {}
+#endif /* CONFIG_IRQ_TIMINGS */
+
+
+#ifdef CONFIG_GENERIC_IRQ_CHIP
+void irq_init_generic_chip(struct irq_chip_generic *gc, const char *name,
+			   int num_ct, unsigned int irq_base,
+			   void __iomem *reg_base, irq_flow_handler_t handler);
+#else
+static inline void
+irq_init_generic_chip(struct irq_chip_generic *gc, const char *name,
+		      int num_ct, unsigned int irq_base,
+		      void __iomem *reg_base, irq_flow_handler_t handler) { }
+#endif /* CONFIG_GENERIC_IRQ_CHIP */
+
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+static inline bool irq_can_move_pcntxt(struct irq_data *data)
+{
+	return irqd_can_move_in_process_context(data);
+}
+static inline bool irq_move_pending(struct irq_data *data)
+{
+	return irqd_is_setaffinity_pending(data);
+}
+static inline void
+irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
+{
+	cpumask_copy(desc->pending_mask, mask);
+}
+static inline void
+irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
+{
+	cpumask_copy(mask, desc->pending_mask);
+}
+static inline struct cpumask *irq_desc_get_pending_mask(struct irq_desc *desc)
+{
+	return desc->pending_mask;
+}
+static inline bool handle_enforce_irqctx(struct irq_data *data)
+{
+	return irqd_is_handle_enforce_irqctx(data);
+}
+bool irq_fixup_move_pending(struct irq_desc *desc, bool force_clear);
+#else /* CONFIG_GENERIC_PENDING_IRQ */
+static inline bool irq_can_move_pcntxt(struct irq_data *data)
+{
+	return true;
+}
+static inline bool irq_move_pending(struct irq_data *data)
+{
+	return false;
+}
+static inline void
+irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
+{
+}
+static inline void
+irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
+{
+}
+static inline struct cpumask *irq_desc_get_pending_mask(struct irq_desc *desc)
+{
+	return NULL;
+}
+static inline bool irq_fixup_move_pending(struct irq_desc *desc, bool fclear)
+{
+	return false;
+}
+static inline bool handle_enforce_irqctx(struct irq_data *data)
+{
+	return false;
+}
+#endif /* !CONFIG_GENERIC_PENDING_IRQ */
+
+#if !defined(CONFIG_IRQ_DOMAIN) || !defined(CONFIG_IRQ_DOMAIN_HIERARCHY)
+static inline int irq_domain_activate_irq(struct irq_data *data, bool reserve)
+{
+	irqd_set_activated(data);
+	return 0;
+}
+static inline void irq_domain_deactivate_irq(struct irq_data *data)
+{
+	irqd_clr_activated(data);
+}
+#endif
+
+static inline struct irq_data *irqd_get_parent_data(struct irq_data *irqd)
+{
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+	return irqd->parent_data;
+#else
+	return NULL;
+#endif
+}
+
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+#include <linux/debugfs.h>
+
+void irq_add_debugfs_entry(unsigned int irq, struct irq_desc *desc);
+static inline void irq_remove_debugfs_entry(struct irq_desc *desc)
+{
+	debugfs_remove(desc->debugfs_file);
+	kfree(desc->dev_name);
+}
+void irq_debugfs_copy_devname(int irq, struct device *dev);
+# ifdef CONFIG_IRQ_DOMAIN
+void irq_domain_debugfs_init(struct dentry *root);
+# else
+static inline void irq_domain_debugfs_init(struct dentry *root)
+{
+}
+# endif
+#else /* CONFIG_GENERIC_IRQ_DEBUGFS */
+static inline void irq_add_debugfs_entry(unsigned int irq, struct irq_desc *d)
+{
+}
+static inline void irq_remove_debugfs_entry(struct irq_desc *d)
+{
+}
+static inline void irq_debugfs_copy_devname(int irq, struct device *dev)
+{
+}
+#endif /* CONFIG_GENERIC_IRQ_DEBUGFS */
diff --git a/kernel/irq/ipi.c b/kernel/irq/ipi.c
new file mode 100644
index 000000000..961d4af76
--- /dev/null
+++ b/kernel/irq/ipi.c
@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015 Imagination Technologies Ltd
+ * Author: Qais Yousef <qais.yousef@imgtec.com>
+ *
+ * This file contains driver APIs to the IPI subsystem.
+ */
+
+#define pr_fmt(fmt) "genirq/ipi: " fmt
+
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+
+/**
+ * irq_reserve_ipi() - Setup an IPI to destination cpumask
+ * @domain:	IPI domain
+ * @dest:	cpumask of CPUs which can receive the IPI
+ *
+ * Allocate a virq that can be used to send IPI to any CPU in dest mask.
+ *
+ * Return: Linux IRQ number on success or error code on failure
+ */
+int irq_reserve_ipi(struct irq_domain *domain,
+			     const struct cpumask *dest)
+{
+	unsigned int nr_irqs, offset;
+	struct irq_data *data;
+	int virq, i;
+
+	if (!domain ||!irq_domain_is_ipi(domain)) {
+		pr_warn("Reservation on a non IPI domain\n");
+		return -EINVAL;
+	}
+
+	if (!cpumask_subset(dest, cpu_possible_mask)) {
+		pr_warn("Reservation is not in possible_cpu_mask\n");
+		return -EINVAL;
+	}
+
+	nr_irqs = cpumask_weight(dest);
+	if (!nr_irqs) {
+		pr_warn("Reservation for empty destination mask\n");
+		return -EINVAL;
+	}
+
+	if (irq_domain_is_ipi_single(domain)) {
+		/*
+		 * If the underlying implementation uses a single HW irq on
+		 * all cpus then we only need a single Linux irq number for
+		 * it. We have no restrictions vs. the destination mask. The
+		 * underlying implementation can deal with holes nicely.
+		 */
+		nr_irqs = 1;
+		offset = 0;
+	} else {
+		unsigned int next;
+
+		/*
+		 * The IPI requires a separate HW irq on each CPU. We require
+		 * that the destination mask is consecutive. If an
+		 * implementation needs to support holes, it can reserve
+		 * several IPI ranges.
+		 */
+		offset = cpumask_first(dest);
+		/*
+		 * Find a hole and if found look for another set bit after the
+		 * hole. For now we don't support this scenario.
+		 */
+		next = cpumask_next_zero(offset, dest);
+		if (next < nr_cpu_ids)
+			next = cpumask_next(next, dest);
+		if (next < nr_cpu_ids) {
+			pr_warn("Destination mask has holes\n");
+			return -EINVAL;
+		}
+	}
+
+	virq = irq_domain_alloc_descs(-1, nr_irqs, 0, NUMA_NO_NODE, NULL);
+	if (virq <= 0) {
+		pr_warn("Can't reserve IPI, failed to alloc descs\n");
+		return -ENOMEM;
+	}
+
+	virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE,
+				       (void *) dest, true, NULL);
+
+	if (virq <= 0) {
+		pr_warn("Can't reserve IPI, failed to alloc hw irqs\n");
+		goto free_descs;
+	}
+
+	for (i = 0; i < nr_irqs; i++) {
+		data = irq_get_irq_data(virq + i);
+		cpumask_copy(data->common->affinity, dest);
+		data->common->ipi_offset = offset;
+		irq_set_status_flags(virq + i, IRQ_NO_BALANCING);
+	}
+	return virq;
+
+free_descs:
+	irq_free_descs(virq, nr_irqs);
+	return -EBUSY;
+}
+
+/**
+ * irq_destroy_ipi() - unreserve an IPI that was previously allocated
+ * @irq:	Linux IRQ number to be destroyed
+ * @dest:	cpumask of CPUs which should have the IPI removed
+ *
+ * The IPIs allocated with irq_reserve_ipi() are returned to the system
+ * destroying all virqs associated with them.
+ *
+ * Return: %0 on success or error code on failure.
+ */
+int irq_destroy_ipi(unsigned int irq, const struct cpumask *dest)
+{
+	struct irq_data *data = irq_get_irq_data(irq);
+	const struct cpumask *ipimask;
+	struct irq_domain *domain;
+	unsigned int nr_irqs;
+
+	if (!irq || !data)
+		return -EINVAL;
+
+	domain = data->domain;
+	if (WARN_ON(domain == NULL))
+		return -EINVAL;
+
+	if (!irq_domain_is_ipi(domain)) {
+		pr_warn("Trying to destroy a non IPI domain!\n");
+		return -EINVAL;
+	}
+
+	ipimask = irq_data_get_affinity_mask(data);
+	if (!ipimask || WARN_ON(!cpumask_subset(dest, ipimask)))
+		/*
+		 * Must be destroying a subset of CPUs to which this IPI
+		 * was set up to target
+		 */
+		return -EINVAL;
+
+	if (irq_domain_is_ipi_per_cpu(domain)) {
+		irq = irq + cpumask_first(dest) - data->common->ipi_offset;
+		nr_irqs = cpumask_weight(dest);
+	} else {
+		nr_irqs = 1;
+	}
+
+	irq_domain_free_irqs(irq, nr_irqs);
+	return 0;
+}
+
+/**
+ * ipi_get_hwirq - Get the hwirq associated with an IPI to a CPU
+ * @irq:	Linux IRQ number
+ * @cpu:	the target CPU
+ *
+ * When dealing with coprocessors IPI, we need to inform the coprocessor of
+ * the hwirq it needs to use to receive and send IPIs.
+ *
+ * Return: hwirq value on success or INVALID_HWIRQ on failure.
+ */
+irq_hw_number_t ipi_get_hwirq(unsigned int irq, unsigned int cpu)
+{
+	struct irq_data *data = irq_get_irq_data(irq);
+	const struct cpumask *ipimask;
+
+	if (!data || cpu >= nr_cpu_ids)
+		return INVALID_HWIRQ;
+
+	ipimask = irq_data_get_affinity_mask(data);
+	if (!ipimask || !cpumask_test_cpu(cpu, ipimask))
+		return INVALID_HWIRQ;
+
+	/*
+	 * Get the real hardware irq number if the underlying implementation
+	 * uses a separate irq per cpu. If the underlying implementation uses
+	 * a single hardware irq for all cpus then the IPI send mechanism
+	 * needs to take care of the cpu destinations.
+	 */
+	if (irq_domain_is_ipi_per_cpu(data->domain))
+		data = irq_get_irq_data(irq + cpu - data->common->ipi_offset);
+
+	return data ? irqd_to_hwirq(data) : INVALID_HWIRQ;
+}
+EXPORT_SYMBOL_GPL(ipi_get_hwirq);
+
+static int ipi_send_verify(struct irq_chip *chip, struct irq_data *data,
+			   const struct cpumask *dest, unsigned int cpu)
+{
+	const struct cpumask *ipimask;
+
+	if (!chip || !data)
+		return -EINVAL;
+
+	if (!chip->ipi_send_single && !chip->ipi_send_mask)
+		return -EINVAL;
+
+	if (cpu >= nr_cpu_ids)
+		return -EINVAL;
+
+	ipimask = irq_data_get_affinity_mask(data);
+	if (!ipimask)
+		return -EINVAL;
+
+	if (dest) {
+		if (!cpumask_subset(dest, ipimask))
+			return -EINVAL;
+	} else {
+		if (!cpumask_test_cpu(cpu, ipimask))
+			return -EINVAL;
+	}
+	return 0;
+}
+
+/**
+ * __ipi_send_single - send an IPI to a target Linux SMP CPU
+ * @desc:	pointer to irq_desc of the IRQ
+ * @cpu:	destination CPU, must in the destination mask passed to
+ *		irq_reserve_ipi()
+ *
+ * This function is for architecture or core code to speed up IPI sending. Not
+ * usable from driver code.
+ *
+ * Return: %0 on success or negative error number on failure.
+ */
+int __ipi_send_single(struct irq_desc *desc, unsigned int cpu)
+{
+	struct irq_data *data = irq_desc_get_irq_data(desc);
+	struct irq_chip *chip = irq_data_get_irq_chip(data);
+
+#ifdef DEBUG
+	/*
+	 * Minimise the overhead by omitting the checks for Linux SMP IPIs.
+	 * Since the callers should be arch or core code which is generally
+	 * trusted, only check for errors when debugging.
+	 */
+	if (WARN_ON_ONCE(ipi_send_verify(chip, data, NULL, cpu)))
+		return -EINVAL;
+#endif
+	if (!chip->ipi_send_single) {
+		chip->ipi_send_mask(data, cpumask_of(cpu));
+		return 0;
+	}
+
+	/* FIXME: Store this information in irqdata flags */
+	if (irq_domain_is_ipi_per_cpu(data->domain) &&
+	    cpu != data->common->ipi_offset) {
+		/* use the correct data for that cpu */
+		unsigned irq = data->irq + cpu - data->common->ipi_offset;
+
+		data = irq_get_irq_data(irq);
+	}
+	chip->ipi_send_single(data, cpu);
+	return 0;
+}
+
+/**
+ * __ipi_send_mask - send an IPI to target Linux SMP CPU(s)
+ * @desc:	pointer to irq_desc of the IRQ
+ * @dest:	dest CPU(s), must be a subset of the mask passed to
+ *		irq_reserve_ipi()
+ *
+ * This function is for architecture or core code to speed up IPI sending. Not
+ * usable from driver code.
+ *
+ * Return: %0 on success or negative error number on failure.
+ */
+int __ipi_send_mask(struct irq_desc *desc, const struct cpumask *dest)
+{
+	struct irq_data *data = irq_desc_get_irq_data(desc);
+	struct irq_chip *chip = irq_data_get_irq_chip(data);
+	unsigned int cpu;
+
+#ifdef DEBUG
+	/*
+	 * Minimise the overhead by omitting the checks for Linux SMP IPIs.
+	 * Since the callers should be arch or core code which is generally
+	 * trusted, only check for errors when debugging.
+	 */
+	if (WARN_ON_ONCE(ipi_send_verify(chip, data, dest, 0)))
+		return -EINVAL;
+#endif
+	if (chip->ipi_send_mask) {
+		chip->ipi_send_mask(data, dest);
+		return 0;
+	}
+
+	if (irq_domain_is_ipi_per_cpu(data->domain)) {
+		unsigned int base = data->irq;
+
+		for_each_cpu(cpu, dest) {
+			unsigned irq = base + cpu - data->common->ipi_offset;
+
+			data = irq_get_irq_data(irq);
+			chip->ipi_send_single(data, cpu);
+		}
+	} else {
+		for_each_cpu(cpu, dest)
+			chip->ipi_send_single(data, cpu);
+	}
+	return 0;
+}
+
+/**
+ * ipi_send_single - Send an IPI to a single CPU
+ * @virq:	Linux IRQ number from irq_reserve_ipi()
+ * @cpu:	destination CPU, must in the destination mask passed to
+ *		irq_reserve_ipi()
+ *
+ * Return: %0 on success or negative error number on failure.
+ */
+int ipi_send_single(unsigned int virq, unsigned int cpu)
+{
+	struct irq_desc *desc = irq_to_desc(virq);
+	struct irq_data *data = desc ? irq_desc_get_irq_data(desc) : NULL;
+	struct irq_chip *chip = data ? irq_data_get_irq_chip(data) : NULL;
+
+	if (WARN_ON_ONCE(ipi_send_verify(chip, data, NULL, cpu)))
+		return -EINVAL;
+
+	return __ipi_send_single(desc, cpu);
+}
+EXPORT_SYMBOL_GPL(ipi_send_single);
+
+/**
+ * ipi_send_mask - Send an IPI to target CPU(s)
+ * @virq:	Linux IRQ number from irq_reserve_ipi()
+ * @dest:	dest CPU(s), must be a subset of the mask passed to
+ *		irq_reserve_ipi()
+ *
+ * Return: %0 on success or negative error number on failure.
+ */
+int ipi_send_mask(unsigned int virq, const struct cpumask *dest)
+{
+	struct irq_desc *desc = irq_to_desc(virq);
+	struct irq_data *data = desc ? irq_desc_get_irq_data(desc) : NULL;
+	struct irq_chip *chip = data ? irq_data_get_irq_chip(data) : NULL;
+
+	if (WARN_ON_ONCE(ipi_send_verify(chip, data, dest, 0)))
+		return -EINVAL;
+
+	return __ipi_send_mask(desc, dest);
+}
+EXPORT_SYMBOL_GPL(ipi_send_mask);
diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
new file mode 100644
index 000000000..dd76323ea
--- /dev/null
+++ b/kernel/irq/irq_sim.c
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017-2018 Bartosz Golaszewski <brgl@bgdev.pl>
+ * Copyright (C) 2020 Bartosz Golaszewski <bgolaszewski@baylibre.com>
+ */
+
+#include <linux/irq.h>
+#include <linux/irq_sim.h>
+#include <linux/irq_work.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+
+struct irq_sim_work_ctx {
+	struct irq_work		work;
+	int			irq_base;
+	unsigned int		irq_count;
+	unsigned long		*pending;
+	struct irq_domain	*domain;
+};
+
+struct irq_sim_irq_ctx {
+	int			irqnum;
+	bool			enabled;
+	struct irq_sim_work_ctx	*work_ctx;
+};
+
+static void irq_sim_irqmask(struct irq_data *data)
+{
+	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
+
+	irq_ctx->enabled = false;
+}
+
+static void irq_sim_irqunmask(struct irq_data *data)
+{
+	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
+
+	irq_ctx->enabled = true;
+}
+
+static int irq_sim_set_type(struct irq_data *data, unsigned int type)
+{
+	/* We only support rising and falling edge trigger types. */
+	if (type & ~IRQ_TYPE_EDGE_BOTH)
+		return -EINVAL;
+
+	irqd_set_trigger_type(data, type);
+
+	return 0;
+}
+
+static int irq_sim_get_irqchip_state(struct irq_data *data,
+				     enum irqchip_irq_state which, bool *state)
+{
+	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
+	irq_hw_number_t hwirq = irqd_to_hwirq(data);
+
+	switch (which) {
+	case IRQCHIP_STATE_PENDING:
+		if (irq_ctx->enabled)
+			*state = test_bit(hwirq, irq_ctx->work_ctx->pending);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int irq_sim_set_irqchip_state(struct irq_data *data,
+				     enum irqchip_irq_state which, bool state)
+{
+	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
+	irq_hw_number_t hwirq = irqd_to_hwirq(data);
+
+	switch (which) {
+	case IRQCHIP_STATE_PENDING:
+		if (irq_ctx->enabled) {
+			assign_bit(hwirq, irq_ctx->work_ctx->pending, state);
+			if (state)
+				irq_work_queue(&irq_ctx->work_ctx->work);
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct irq_chip irq_sim_irqchip = {
+	.name			= "irq_sim",
+	.irq_mask		= irq_sim_irqmask,
+	.irq_unmask		= irq_sim_irqunmask,
+	.irq_set_type		= irq_sim_set_type,
+	.irq_get_irqchip_state	= irq_sim_get_irqchip_state,
+	.irq_set_irqchip_state	= irq_sim_set_irqchip_state,
+};
+
+static void irq_sim_handle_irq(struct irq_work *work)
+{
+	struct irq_sim_work_ctx *work_ctx;
+	unsigned int offset = 0;
+	int irqnum;
+
+	work_ctx = container_of(work, struct irq_sim_work_ctx, work);
+
+	while (!bitmap_empty(work_ctx->pending, work_ctx->irq_count)) {
+		offset = find_next_bit(work_ctx->pending,
+				       work_ctx->irq_count, offset);
+		clear_bit(offset, work_ctx->pending);
+		irqnum = irq_find_mapping(work_ctx->domain, offset);
+		handle_simple_irq(irq_to_desc(irqnum));
+	}
+}
+
+static int irq_sim_domain_map(struct irq_domain *domain,
+			      unsigned int virq, irq_hw_number_t hw)
+{
+	struct irq_sim_work_ctx *work_ctx = domain->host_data;
+	struct irq_sim_irq_ctx *irq_ctx;
+
+	irq_ctx = kzalloc(sizeof(*irq_ctx), GFP_KERNEL);
+	if (!irq_ctx)
+		return -ENOMEM;
+
+	irq_set_chip(virq, &irq_sim_irqchip);
+	irq_set_chip_data(virq, irq_ctx);
+	irq_set_handler(virq, handle_simple_irq);
+	irq_modify_status(virq, IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
+	irq_ctx->work_ctx = work_ctx;
+
+	return 0;
+}
+
+static void irq_sim_domain_unmap(struct irq_domain *domain, unsigned int virq)
+{
+	struct irq_sim_irq_ctx *irq_ctx;
+	struct irq_data *irqd;
+
+	irqd = irq_domain_get_irq_data(domain, virq);
+	irq_ctx = irq_data_get_irq_chip_data(irqd);
+
+	irq_set_handler(virq, NULL);
+	irq_domain_reset_irq_data(irqd);
+	kfree(irq_ctx);
+}
+
+static const struct irq_domain_ops irq_sim_domain_ops = {
+	.map		= irq_sim_domain_map,
+	.unmap		= irq_sim_domain_unmap,
+};
+
+/**
+ * irq_domain_create_sim - Create a new interrupt simulator irq_domain and
+ *                         allocate a range of dummy interrupts.
+ *
+ * @fwnode:     struct fwnode_handle to be associated with this domain.
+ * @num_irqs:   Number of interrupts to allocate.
+ *
+ * On success: return a new irq_domain object.
+ * On failure: a negative errno wrapped with ERR_PTR().
+ */
+struct irq_domain *irq_domain_create_sim(struct fwnode_handle *fwnode,
+					 unsigned int num_irqs)
+{
+	struct irq_sim_work_ctx *work_ctx;
+
+	work_ctx = kmalloc(sizeof(*work_ctx), GFP_KERNEL);
+	if (!work_ctx)
+		goto err_out;
+
+	work_ctx->pending = bitmap_zalloc(num_irqs, GFP_KERNEL);
+	if (!work_ctx->pending)
+		goto err_free_work_ctx;
+
+	work_ctx->domain = irq_domain_create_linear(fwnode, num_irqs,
+						    &irq_sim_domain_ops,
+						    work_ctx);
+	if (!work_ctx->domain)
+		goto err_free_bitmap;
+
+	work_ctx->irq_count = num_irqs;
+	work_ctx->work = IRQ_WORK_INIT_HARD(irq_sim_handle_irq);
+
+	return work_ctx->domain;
+
+err_free_bitmap:
+	bitmap_free(work_ctx->pending);
+err_free_work_ctx:
+	kfree(work_ctx);
+err_out:
+	return ERR_PTR(-ENOMEM);
+}
+EXPORT_SYMBOL_GPL(irq_domain_create_sim);
+
+/**
+ * irq_domain_remove_sim - Deinitialize the interrupt simulator domain: free
+ *                         the interrupt descriptors and allocated memory.
+ *
+ * @domain:     The interrupt simulator domain to tear down.
+ */
+void irq_domain_remove_sim(struct irq_domain *domain)
+{
+	struct irq_sim_work_ctx *work_ctx = domain->host_data;
+
+	irq_work_sync(&work_ctx->work);
+	bitmap_free(work_ctx->pending);
+	kfree(work_ctx);
+
+	irq_domain_remove(domain);
+}
+EXPORT_SYMBOL_GPL(irq_domain_remove_sim);
+
+static void devm_irq_domain_remove_sim(void *data)
+{
+	struct irq_domain *domain = data;
+
+	irq_domain_remove_sim(domain);
+}
+
+/**
+ * devm_irq_domain_create_sim - Create a new interrupt simulator for
+ *                              a managed device.
+ *
+ * @dev:        Device to initialize the simulator object for.
+ * @fwnode:     struct fwnode_handle to be associated with this domain.
+ * @num_irqs:   Number of interrupts to allocate
+ *
+ * On success: return a new irq_domain object.
+ * On failure: a negative errno wrapped with ERR_PTR().
+ */
+struct irq_domain *devm_irq_domain_create_sim(struct device *dev,
+					      struct fwnode_handle *fwnode,
+					      unsigned int num_irqs)
+{
+	struct irq_domain *domain;
+	int ret;
+
+	domain = irq_domain_create_sim(fwnode, num_irqs);
+	if (IS_ERR(domain))
+		return domain;
+
+	ret = devm_add_action_or_reset(dev, devm_irq_domain_remove_sim, domain);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return domain;
+}
+EXPORT_SYMBOL_GPL(devm_irq_domain_create_sim);
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
new file mode 100644
index 000000000..fd0996274
--- /dev/null
+++ b/kernel/irq/irqdesc.c
@@ -0,0 +1,995 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
+ * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
+ *
+ * This file contains the interrupt descriptor management code. Detailed
+ * information is available in Documentation/core-api/genericirq.rst
+ *
+ */
+#include <linux/irq.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+#include <linux/radix-tree.h>
+#include <linux/bitmap.h>
+#include <linux/irqdomain.h>
+#include <linux/sysfs.h>
+
+#include "internals.h"
+
+/*
+ * lockdep: we want to handle all irq_desc locks as a single lock-class:
+ */
+static struct lock_class_key irq_desc_lock_class;
+
+#if defined(CONFIG_SMP)
+static int __init irq_affinity_setup(char *str)
+{
+	alloc_bootmem_cpumask_var(&irq_default_affinity);
+	cpulist_parse(str, irq_default_affinity);
+	/*
+	 * Set at least the boot cpu. We don't want to end up with
+	 * bugreports caused by random commandline masks
+	 */
+	cpumask_set_cpu(smp_processor_id(), irq_default_affinity);
+	return 1;
+}
+__setup("irqaffinity=", irq_affinity_setup);
+
+static void __init init_irq_default_affinity(void)
+{
+	if (!cpumask_available(irq_default_affinity))
+		zalloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
+	if (cpumask_empty(irq_default_affinity))
+		cpumask_setall(irq_default_affinity);
+}
+#else
+static void __init init_irq_default_affinity(void)
+{
+}
+#endif
+
+#ifdef CONFIG_SMP
+static int alloc_masks(struct irq_desc *desc, int node)
+{
+	if (!zalloc_cpumask_var_node(&desc->irq_common_data.affinity,
+				     GFP_KERNEL, node))
+		return -ENOMEM;
+
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	if (!zalloc_cpumask_var_node(&desc->irq_common_data.effective_affinity,
+				     GFP_KERNEL, node)) {
+		free_cpumask_var(desc->irq_common_data.affinity);
+		return -ENOMEM;
+	}
+#endif
+
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+	if (!zalloc_cpumask_var_node(&desc->pending_mask, GFP_KERNEL, node)) {
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+		free_cpumask_var(desc->irq_common_data.effective_affinity);
+#endif
+		free_cpumask_var(desc->irq_common_data.affinity);
+		return -ENOMEM;
+	}
+#endif
+	return 0;
+}
+
+static void desc_smp_init(struct irq_desc *desc, int node,
+			  const struct cpumask *affinity)
+{
+	if (!affinity)
+		affinity = irq_default_affinity;
+	cpumask_copy(desc->irq_common_data.affinity, affinity);
+
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+	cpumask_clear(desc->pending_mask);
+#endif
+#ifdef CONFIG_NUMA
+	desc->irq_common_data.node = node;
+#endif
+}
+
+#else
+static inline int
+alloc_masks(struct irq_desc *desc, int node) { return 0; }
+static inline void
+desc_smp_init(struct irq_desc *desc, int node, const struct cpumask *affinity) { }
+#endif
+
+static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node,
+			      const struct cpumask *affinity, struct module *owner)
+{
+	int cpu;
+
+	desc->irq_common_data.handler_data = NULL;
+	desc->irq_common_data.msi_desc = NULL;
+
+	desc->irq_data.common = &desc->irq_common_data;
+	desc->irq_data.irq = irq;
+	desc->irq_data.chip = &no_irq_chip;
+	desc->irq_data.chip_data = NULL;
+	irq_settings_clr_and_set(desc, ~0, _IRQ_DEFAULT_INIT_FLAGS);
+	irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED);
+	irqd_set(&desc->irq_data, IRQD_IRQ_MASKED);
+	desc->handle_irq = handle_bad_irq;
+	desc->depth = 1;
+	desc->irq_count = 0;
+	desc->irqs_unhandled = 0;
+	desc->tot_count = 0;
+	desc->name = NULL;
+	desc->owner = owner;
+	for_each_possible_cpu(cpu)
+		*per_cpu_ptr(desc->kstat_irqs, cpu) = 0;
+	desc_smp_init(desc, node, affinity);
+}
+
+int nr_irqs = NR_IRQS;
+EXPORT_SYMBOL_GPL(nr_irqs);
+
+static DEFINE_MUTEX(sparse_irq_lock);
+static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS);
+
+#ifdef CONFIG_SPARSE_IRQ
+
+static void irq_kobj_release(struct kobject *kobj);
+
+#ifdef CONFIG_SYSFS
+static struct kobject *irq_kobj_base;
+
+#define IRQ_ATTR_RO(_name) \
+static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
+
+static ssize_t per_cpu_count_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+	ssize_t ret = 0;
+	char *p = "";
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		unsigned int c = irq_desc_kstat_cpu(desc, cpu);
+
+		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%u", p, c);
+		p = ",";
+	}
+
+	ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");
+	return ret;
+}
+IRQ_ATTR_RO(per_cpu_count);
+
+static ssize_t chip_name_show(struct kobject *kobj,
+			      struct kobj_attribute *attr, char *buf)
+{
+	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+	ssize_t ret = 0;
+
+	raw_spin_lock_irq(&desc->lock);
+	if (desc->irq_data.chip && desc->irq_data.chip->name) {
+		ret = scnprintf(buf, PAGE_SIZE, "%s\n",
+				desc->irq_data.chip->name);
+	}
+	raw_spin_unlock_irq(&desc->lock);
+
+	return ret;
+}
+IRQ_ATTR_RO(chip_name);
+
+static ssize_t hwirq_show(struct kobject *kobj,
+			  struct kobj_attribute *attr, char *buf)
+{
+	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+	ssize_t ret = 0;
+
+	raw_spin_lock_irq(&desc->lock);
+	if (desc->irq_data.domain)
+		ret = sprintf(buf, "%lu\n", desc->irq_data.hwirq);
+	raw_spin_unlock_irq(&desc->lock);
+
+	return ret;
+}
+IRQ_ATTR_RO(hwirq);
+
+static ssize_t type_show(struct kobject *kobj,
+			 struct kobj_attribute *attr, char *buf)
+{
+	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+	ssize_t ret = 0;
+
+	raw_spin_lock_irq(&desc->lock);
+	ret = sprintf(buf, "%s\n",
+		      irqd_is_level_type(&desc->irq_data) ? "level" : "edge");
+	raw_spin_unlock_irq(&desc->lock);
+
+	return ret;
+
+}
+IRQ_ATTR_RO(type);
+
+static ssize_t wakeup_show(struct kobject *kobj,
+			   struct kobj_attribute *attr, char *buf)
+{
+	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+	ssize_t ret = 0;
+
+	raw_spin_lock_irq(&desc->lock);
+	ret = sprintf(buf, "%s\n",
+		      irqd_is_wakeup_set(&desc->irq_data) ? "enabled" : "disabled");
+	raw_spin_unlock_irq(&desc->lock);
+
+	return ret;
+
+}
+IRQ_ATTR_RO(wakeup);
+
+static ssize_t name_show(struct kobject *kobj,
+			 struct kobj_attribute *attr, char *buf)
+{
+	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+	ssize_t ret = 0;
+
+	raw_spin_lock_irq(&desc->lock);
+	if (desc->name)
+		ret = scnprintf(buf, PAGE_SIZE, "%s\n", desc->name);
+	raw_spin_unlock_irq(&desc->lock);
+
+	return ret;
+}
+IRQ_ATTR_RO(name);
+
+static ssize_t actions_show(struct kobject *kobj,
+			    struct kobj_attribute *attr, char *buf)
+{
+	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+	struct irqaction *action;
+	ssize_t ret = 0;
+	char *p = "";
+
+	raw_spin_lock_irq(&desc->lock);
+	for_each_action_of_desc(desc, action) {
+		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
+				 p, action->name);
+		p = ",";
+	}
+	raw_spin_unlock_irq(&desc->lock);
+
+	if (ret)
+		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");
+
+	return ret;
+}
+IRQ_ATTR_RO(actions);
+
+static struct attribute *irq_attrs[] = {
+	&per_cpu_count_attr.attr,
+	&chip_name_attr.attr,
+	&hwirq_attr.attr,
+	&type_attr.attr,
+	&wakeup_attr.attr,
+	&name_attr.attr,
+	&actions_attr.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(irq);
+
+static struct kobj_type irq_kobj_type = {
+	.release	= irq_kobj_release,
+	.sysfs_ops	= &kobj_sysfs_ops,
+	.default_groups = irq_groups,
+};
+
+static void irq_sysfs_add(int irq, struct irq_desc *desc)
+{
+	if (irq_kobj_base) {
+		/*
+		 * Continue even in case of failure as this is nothing
+		 * crucial and failures in the late irq_sysfs_init()
+		 * cannot be rolled back.
+		 */
+		if (kobject_add(&desc->kobj, irq_kobj_base, "%d", irq))
+			pr_warn("Failed to add kobject for irq %d\n", irq);
+		else
+			desc->istate |= IRQS_SYSFS;
+	}
+}
+
+static void irq_sysfs_del(struct irq_desc *desc)
+{
+	/*
+	 * Only invoke kobject_del() when kobject_add() was successfully
+	 * invoked for the descriptor. This covers both early boot, where
+	 * sysfs is not initialized yet, and the case of a failed
+	 * kobject_add() invocation.
+	 */
+	if (desc->istate & IRQS_SYSFS)
+		kobject_del(&desc->kobj);
+}
+
+static int __init irq_sysfs_init(void)
+{
+	struct irq_desc *desc;
+	int irq;
+
+	/* Prevent concurrent irq alloc/free */
+	irq_lock_sparse();
+
+	irq_kobj_base = kobject_create_and_add("irq", kernel_kobj);
+	if (!irq_kobj_base) {
+		irq_unlock_sparse();
+		return -ENOMEM;
+	}
+
+	/* Add the already allocated interrupts */
+	for_each_irq_desc(irq, desc)
+		irq_sysfs_add(irq, desc);
+	irq_unlock_sparse();
+
+	return 0;
+}
+postcore_initcall(irq_sysfs_init);
+
+#else /* !CONFIG_SYSFS */
+
+static struct kobj_type irq_kobj_type = {
+	.release	= irq_kobj_release,
+};
+
+static void irq_sysfs_add(int irq, struct irq_desc *desc) {}
+static void irq_sysfs_del(struct irq_desc *desc) {}
+
+#endif /* CONFIG_SYSFS */
+
+static RADIX_TREE(irq_desc_tree, GFP_KERNEL);
+
+static void irq_insert_desc(unsigned int irq, struct irq_desc *desc)
+{
+	radix_tree_insert(&irq_desc_tree, irq, desc);
+}
+
+struct irq_desc *irq_to_desc(unsigned int irq)
+{
+	return radix_tree_lookup(&irq_desc_tree, irq);
+}
+#ifdef CONFIG_KVM_BOOK3S_64_HV_MODULE
+EXPORT_SYMBOL_GPL(irq_to_desc);
+#endif
+
+static void delete_irq_desc(unsigned int irq)
+{
+	radix_tree_delete(&irq_desc_tree, irq);
+}
+
+#ifdef CONFIG_SMP
+static void free_masks(struct irq_desc *desc)
+{
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+	free_cpumask_var(desc->pending_mask);
+#endif
+	free_cpumask_var(desc->irq_common_data.affinity);
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	free_cpumask_var(desc->irq_common_data.effective_affinity);
+#endif
+}
+#else
+static inline void free_masks(struct irq_desc *desc) { }
+#endif
+
+void irq_lock_sparse(void)
+{
+	mutex_lock(&sparse_irq_lock);
+}
+
+void irq_unlock_sparse(void)
+{
+	mutex_unlock(&sparse_irq_lock);
+}
+
+static struct irq_desc *alloc_desc(int irq, int node, unsigned int flags,
+				   const struct cpumask *affinity,
+				   struct module *owner)
+{
+	struct irq_desc *desc;
+
+	desc = kzalloc_node(sizeof(*desc), GFP_KERNEL, node);
+	if (!desc)
+		return NULL;
+	/* allocate based on nr_cpu_ids */
+	desc->kstat_irqs = alloc_percpu(unsigned int);
+	if (!desc->kstat_irqs)
+		goto err_desc;
+
+	if (alloc_masks(desc, node))
+		goto err_kstat;
+
+	raw_spin_lock_init(&desc->lock);
+	lockdep_set_class(&desc->lock, &irq_desc_lock_class);
+	mutex_init(&desc->request_mutex);
+	init_rcu_head(&desc->rcu);
+	init_waitqueue_head(&desc->wait_for_threads);
+
+	desc_set_defaults(irq, desc, node, affinity, owner);
+	irqd_set(&desc->irq_data, flags);
+	kobject_init(&desc->kobj, &irq_kobj_type);
+
+	return desc;
+
+err_kstat:
+	free_percpu(desc->kstat_irqs);
+err_desc:
+	kfree(desc);
+	return NULL;
+}
+
+static void irq_kobj_release(struct kobject *kobj)
+{
+	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
+
+	free_masks(desc);
+	free_percpu(desc->kstat_irqs);
+	kfree(desc);
+}
+
+static void delayed_free_desc(struct rcu_head *rhp)
+{
+	struct irq_desc *desc = container_of(rhp, struct irq_desc, rcu);
+
+	kobject_put(&desc->kobj);
+}
+
+static void free_desc(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	irq_remove_debugfs_entry(desc);
+	unregister_irq_proc(irq, desc);
+
+	/*
+	 * sparse_irq_lock protects also show_interrupts() and
+	 * kstat_irq_usr(). Once we deleted the descriptor from the
+	 * sparse tree we can free it. Access in proc will fail to
+	 * lookup the descriptor.
+	 *
+	 * The sysfs entry must be serialized against a concurrent
+	 * irq_sysfs_init() as well.
+	 */
+	irq_sysfs_del(desc);
+	delete_irq_desc(irq);
+
+	/*
+	 * We free the descriptor, masks and stat fields via RCU. That
+	 * allows demultiplex interrupts to do rcu based management of
+	 * the child interrupts.
+	 * This also allows us to use rcu in kstat_irqs_usr().
+	 */
+	call_rcu(&desc->rcu, delayed_free_desc);
+}
+
+static int alloc_descs(unsigned int start, unsigned int cnt, int node,
+		       const struct irq_affinity_desc *affinity,
+		       struct module *owner)
+{
+	struct irq_desc *desc;
+	int i;
+
+	/* Validate affinity mask(s) */
+	if (affinity) {
+		for (i = 0; i < cnt; i++) {
+			if (cpumask_empty(&affinity[i].mask))
+				return -EINVAL;
+		}
+	}
+
+	for (i = 0; i < cnt; i++) {
+		const struct cpumask *mask = NULL;
+		unsigned int flags = 0;
+
+		if (affinity) {
+			if (affinity->is_managed) {
+				flags = IRQD_AFFINITY_MANAGED |
+					IRQD_MANAGED_SHUTDOWN;
+			}
+			mask = &affinity->mask;
+			node = cpu_to_node(cpumask_first(mask));
+			affinity++;
+		}
+
+		desc = alloc_desc(start + i, node, flags, mask, owner);
+		if (!desc)
+			goto err;
+		irq_insert_desc(start + i, desc);
+		irq_sysfs_add(start + i, desc);
+		irq_add_debugfs_entry(start + i, desc);
+	}
+	bitmap_set(allocated_irqs, start, cnt);
+	return start;
+
+err:
+	for (i--; i >= 0; i--)
+		free_desc(start + i);
+	return -ENOMEM;
+}
+
+static int irq_expand_nr_irqs(unsigned int nr)
+{
+	if (nr > IRQ_BITMAP_BITS)
+		return -ENOMEM;
+	nr_irqs = nr;
+	return 0;
+}
+
+int __init early_irq_init(void)
+{
+	int i, initcnt, node = first_online_node;
+	struct irq_desc *desc;
+
+	init_irq_default_affinity();
+
+	/* Let arch update nr_irqs and return the nr of preallocated irqs */
+	initcnt = arch_probe_nr_irqs();
+	printk(KERN_INFO "NR_IRQS: %d, nr_irqs: %d, preallocated irqs: %d\n",
+	       NR_IRQS, nr_irqs, initcnt);
+
+	if (WARN_ON(nr_irqs > IRQ_BITMAP_BITS))
+		nr_irqs = IRQ_BITMAP_BITS;
+
+	if (WARN_ON(initcnt > IRQ_BITMAP_BITS))
+		initcnt = IRQ_BITMAP_BITS;
+
+	if (initcnt > nr_irqs)
+		nr_irqs = initcnt;
+
+	for (i = 0; i < initcnt; i++) {
+		desc = alloc_desc(i, node, 0, NULL, NULL);
+		set_bit(i, allocated_irqs);
+		irq_insert_desc(i, desc);
+	}
+	return arch_early_irq_init();
+}
+
+#else /* !CONFIG_SPARSE_IRQ */
+
+struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
+	[0 ... NR_IRQS-1] = {
+		.handle_irq	= handle_bad_irq,
+		.depth		= 1,
+		.lock		= __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
+	}
+};
+
+int __init early_irq_init(void)
+{
+	int count, i, node = first_online_node;
+	struct irq_desc *desc;
+
+	init_irq_default_affinity();
+
+	printk(KERN_INFO "NR_IRQS: %d\n", NR_IRQS);
+
+	desc = irq_desc;
+	count = ARRAY_SIZE(irq_desc);
+
+	for (i = 0; i < count; i++) {
+		desc[i].kstat_irqs = alloc_percpu(unsigned int);
+		alloc_masks(&desc[i], node);
+		raw_spin_lock_init(&desc[i].lock);
+		lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
+		mutex_init(&desc[i].request_mutex);
+		init_waitqueue_head(&desc[i].wait_for_threads);
+		desc_set_defaults(i, &desc[i], node, NULL, NULL);
+	}
+	return arch_early_irq_init();
+}
+
+struct irq_desc *irq_to_desc(unsigned int irq)
+{
+	return (irq < NR_IRQS) ? irq_desc + irq : NULL;
+}
+EXPORT_SYMBOL(irq_to_desc);
+
+static void free_desc(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&desc->lock, flags);
+	desc_set_defaults(irq, desc, irq_desc_get_node(desc), NULL, NULL);
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+}
+
+static inline int alloc_descs(unsigned int start, unsigned int cnt, int node,
+			      const struct irq_affinity_desc *affinity,
+			      struct module *owner)
+{
+	u32 i;
+
+	for (i = 0; i < cnt; i++) {
+		struct irq_desc *desc = irq_to_desc(start + i);
+
+		desc->owner = owner;
+	}
+	bitmap_set(allocated_irqs, start, cnt);
+	return start;
+}
+
+static int irq_expand_nr_irqs(unsigned int nr)
+{
+	return -ENOMEM;
+}
+
+void irq_mark_irq(unsigned int irq)
+{
+	mutex_lock(&sparse_irq_lock);
+	bitmap_set(allocated_irqs, irq, 1);
+	mutex_unlock(&sparse_irq_lock);
+}
+
+#ifdef CONFIG_GENERIC_IRQ_LEGACY
+void irq_init_desc(unsigned int irq)
+{
+	free_desc(irq);
+}
+#endif
+
+#endif /* !CONFIG_SPARSE_IRQ */
+
+int handle_irq_desc(struct irq_desc *desc)
+{
+	struct irq_data *data;
+
+	if (!desc)
+		return -EINVAL;
+
+	data = irq_desc_get_irq_data(desc);
+	if (WARN_ON_ONCE(!in_hardirq() && handle_enforce_irqctx(data)))
+		return -EPERM;
+
+	generic_handle_irq_desc(desc);
+	return 0;
+}
+
+/**
+ * generic_handle_irq - Invoke the handler for a particular irq
+ * @irq:	The irq number to handle
+ *
+ * Returns:	0 on success, or -EINVAL if conversion has failed
+ *
+ * 		This function must be called from an IRQ context with irq regs
+ * 		initialized.
+  */
+int generic_handle_irq(unsigned int irq)
+{
+	return handle_irq_desc(irq_to_desc(irq));
+}
+EXPORT_SYMBOL_GPL(generic_handle_irq);
+
+/**
+ * generic_handle_irq_safe - Invoke the handler for a particular irq from any
+ *			     context.
+ * @irq:	The irq number to handle
+ *
+ * Returns:	0 on success, a negative value on error.
+ *
+ * This function can be called from any context (IRQ or process context). It
+ * will report an error if not invoked from IRQ context and the irq has been
+ * marked to enforce IRQ-context only.
+ */
+int generic_handle_irq_safe(unsigned int irq)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+	ret = handle_irq_desc(irq_to_desc(irq));
+	local_irq_restore(flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(generic_handle_irq_safe);
+
+#ifdef CONFIG_IRQ_DOMAIN
+/**
+ * generic_handle_domain_irq - Invoke the handler for a HW irq belonging
+ *                             to a domain.
+ * @domain:	The domain where to perform the lookup
+ * @hwirq:	The HW irq number to convert to a logical one
+ *
+ * Returns:	0 on success, or -EINVAL if conversion has failed
+ *
+ * 		This function must be called from an IRQ context with irq regs
+ * 		initialized.
+ */
+int generic_handle_domain_irq(struct irq_domain *domain, unsigned int hwirq)
+{
+	return handle_irq_desc(irq_resolve_mapping(domain, hwirq));
+}
+EXPORT_SYMBOL_GPL(generic_handle_domain_irq);
+
+ /**
+ * generic_handle_irq_safe - Invoke the handler for a HW irq belonging
+ *			     to a domain from any context.
+ * @domain:	The domain where to perform the lookup
+ * @hwirq:	The HW irq number to convert to a logical one
+ *
+ * Returns:	0 on success, a negative value on error.
+ *
+ * This function can be called from any context (IRQ or process
+ * context). If the interrupt is marked as 'enforce IRQ-context only' then
+ * the function must be invoked from hard interrupt context.
+ */
+int generic_handle_domain_irq_safe(struct irq_domain *domain, unsigned int hwirq)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+	ret = handle_irq_desc(irq_resolve_mapping(domain, hwirq));
+	local_irq_restore(flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(generic_handle_domain_irq_safe);
+
+/**
+ * generic_handle_domain_nmi - Invoke the handler for a HW nmi belonging
+ *                             to a domain.
+ * @domain:	The domain where to perform the lookup
+ * @hwirq:	The HW irq number to convert to a logical one
+ *
+ * Returns:	0 on success, or -EINVAL if conversion has failed
+ *
+ * 		This function must be called from an NMI context with irq regs
+ * 		initialized.
+ **/
+int generic_handle_domain_nmi(struct irq_domain *domain, unsigned int hwirq)
+{
+	WARN_ON_ONCE(!in_nmi());
+	return handle_irq_desc(irq_resolve_mapping(domain, hwirq));
+}
+#endif
+
+/* Dynamic interrupt handling */
+
+/**
+ * irq_free_descs - free irq descriptors
+ * @from:	Start of descriptor range
+ * @cnt:	Number of consecutive irqs to free
+ */
+void irq_free_descs(unsigned int from, unsigned int cnt)
+{
+	int i;
+
+	if (from >= nr_irqs || (from + cnt) > nr_irqs)
+		return;
+
+	mutex_lock(&sparse_irq_lock);
+	for (i = 0; i < cnt; i++)
+		free_desc(from + i);
+
+	bitmap_clear(allocated_irqs, from, cnt);
+	mutex_unlock(&sparse_irq_lock);
+}
+EXPORT_SYMBOL_GPL(irq_free_descs);
+
+/**
+ * __irq_alloc_descs - allocate and initialize a range of irq descriptors
+ * @irq:	Allocate for specific irq number if irq >= 0
+ * @from:	Start the search from this irq number
+ * @cnt:	Number of consecutive irqs to allocate.
+ * @node:	Preferred node on which the irq descriptor should be allocated
+ * @owner:	Owning module (can be NULL)
+ * @affinity:	Optional pointer to an affinity mask array of size @cnt which
+ *		hints where the irq descriptors should be allocated and which
+ *		default affinities to use
+ *
+ * Returns the first irq number or error code
+ */
+int __ref
+__irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
+		  struct module *owner, const struct irq_affinity_desc *affinity)
+{
+	int start, ret;
+
+	if (!cnt)
+		return -EINVAL;
+
+	if (irq >= 0) {
+		if (from > irq)
+			return -EINVAL;
+		from = irq;
+	} else {
+		/*
+		 * For interrupts which are freely allocated the
+		 * architecture can force a lower bound to the @from
+		 * argument. x86 uses this to exclude the GSI space.
+		 */
+		from = arch_dynirq_lower_bound(from);
+	}
+
+	mutex_lock(&sparse_irq_lock);
+
+	start = bitmap_find_next_zero_area(allocated_irqs, IRQ_BITMAP_BITS,
+					   from, cnt, 0);
+	ret = -EEXIST;
+	if (irq >=0 && start != irq)
+		goto unlock;
+
+	if (start + cnt > nr_irqs) {
+		ret = irq_expand_nr_irqs(start + cnt);
+		if (ret)
+			goto unlock;
+	}
+	ret = alloc_descs(start, cnt, node, affinity, owner);
+unlock:
+	mutex_unlock(&sparse_irq_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__irq_alloc_descs);
+
+/**
+ * irq_get_next_irq - get next allocated irq number
+ * @offset:	where to start the search
+ *
+ * Returns next irq number after offset or nr_irqs if none is found.
+ */
+unsigned int irq_get_next_irq(unsigned int offset)
+{
+	return find_next_bit(allocated_irqs, nr_irqs, offset);
+}
+
+struct irq_desc *
+__irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus,
+		    unsigned int check)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	if (desc) {
+		if (check & _IRQ_DESC_CHECK) {
+			if ((check & _IRQ_DESC_PERCPU) &&
+			    !irq_settings_is_per_cpu_devid(desc))
+				return NULL;
+
+			if (!(check & _IRQ_DESC_PERCPU) &&
+			    irq_settings_is_per_cpu_devid(desc))
+				return NULL;
+		}
+
+		if (bus)
+			chip_bus_lock(desc);
+		raw_spin_lock_irqsave(&desc->lock, *flags);
+	}
+	return desc;
+}
+
+void __irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags, bool bus)
+	__releases(&desc->lock)
+{
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+	if (bus)
+		chip_bus_sync_unlock(desc);
+}
+
+int irq_set_percpu_devid_partition(unsigned int irq,
+				   const struct cpumask *affinity)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	if (!desc)
+		return -EINVAL;
+
+	if (desc->percpu_enabled)
+		return -EINVAL;
+
+	desc->percpu_enabled = kzalloc(sizeof(*desc->percpu_enabled), GFP_KERNEL);
+
+	if (!desc->percpu_enabled)
+		return -ENOMEM;
+
+	if (affinity)
+		desc->percpu_affinity = affinity;
+	else
+		desc->percpu_affinity = cpu_possible_mask;
+
+	irq_set_percpu_devid_flags(irq);
+	return 0;
+}
+
+int irq_set_percpu_devid(unsigned int irq)
+{
+	return irq_set_percpu_devid_partition(irq, NULL);
+}
+
+int irq_get_percpu_devid_partition(unsigned int irq, struct cpumask *affinity)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	if (!desc || !desc->percpu_enabled)
+		return -EINVAL;
+
+	if (affinity)
+		cpumask_copy(affinity, desc->percpu_affinity);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_get_percpu_devid_partition);
+
+void kstat_incr_irq_this_cpu(unsigned int irq)
+{
+	kstat_incr_irqs_this_cpu(irq_to_desc(irq));
+}
+
+/**
+ * kstat_irqs_cpu - Get the statistics for an interrupt on a cpu
+ * @irq:	The interrupt number
+ * @cpu:	The cpu number
+ *
+ * Returns the sum of interrupt counts on @cpu since boot for
+ * @irq. The caller must ensure that the interrupt is not removed
+ * concurrently.
+ */
+unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	return desc && desc->kstat_irqs ?
+			*per_cpu_ptr(desc->kstat_irqs, cpu) : 0;
+}
+
+static bool irq_is_nmi(struct irq_desc *desc)
+{
+	return desc->istate & IRQS_NMI;
+}
+
+static unsigned int kstat_irqs(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	unsigned int sum = 0;
+	int cpu;
+
+	if (!desc || !desc->kstat_irqs)
+		return 0;
+	if (!irq_settings_is_per_cpu_devid(desc) &&
+	    !irq_settings_is_per_cpu(desc) &&
+	    !irq_is_nmi(desc))
+		return data_race(desc->tot_count);
+
+	for_each_possible_cpu(cpu)
+		sum += data_race(*per_cpu_ptr(desc->kstat_irqs, cpu));
+	return sum;
+}
+
+/**
+ * kstat_irqs_usr - Get the statistics for an interrupt from thread context
+ * @irq:	The interrupt number
+ *
+ * Returns the sum of interrupt counts on all cpus since boot for @irq.
+ *
+ * It uses rcu to protect the access since a concurrent removal of an
+ * interrupt descriptor is observing an rcu grace period before
+ * delayed_free_desc()/irq_kobj_release().
+ */
+unsigned int kstat_irqs_usr(unsigned int irq)
+{
+	unsigned int sum;
+
+	rcu_read_lock();
+	sum = kstat_irqs(irq);
+	rcu_read_unlock();
+	return sum;
+}
+
+#ifdef CONFIG_LOCKDEP
+void __irq_set_lockdep_class(unsigned int irq, struct lock_class_key *lock_class,
+			     struct lock_class_key *request_class)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	if (desc) {
+		lockdep_set_class(&desc->lock, lock_class);
+		lockdep_set_class(&desc->request_mutex, request_class);
+	}
+}
+EXPORT_SYMBOL_GPL(__irq_set_lockdep_class);
+#endif
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
new file mode 100644
index 000000000..607c0c3d3
--- /dev/null
+++ b/kernel/irq/irqdomain.c
@@ -0,0 +1,2009 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define pr_fmt(fmt)  "irq: " fmt
+
+#include <linux/acpi.h>
+#include <linux/debugfs.h>
+#include <linux/hardirq.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqdesc.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/topology.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+#include <linux/fs.h>
+
+static LIST_HEAD(irq_domain_list);
+static DEFINE_MUTEX(irq_domain_mutex);
+
+static struct irq_domain *irq_default_domain;
+
+static int irq_domain_alloc_irqs_locked(struct irq_domain *domain, int irq_base,
+					unsigned int nr_irqs, int node, void *arg,
+					bool realloc, const struct irq_affinity_desc *affinity);
+static void irq_domain_check_hierarchy(struct irq_domain *domain);
+
+struct irqchip_fwid {
+	struct fwnode_handle	fwnode;
+	unsigned int		type;
+	char			*name;
+	phys_addr_t		*pa;
+};
+
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+static void debugfs_add_domain_dir(struct irq_domain *d);
+static void debugfs_remove_domain_dir(struct irq_domain *d);
+#else
+static inline void debugfs_add_domain_dir(struct irq_domain *d) { }
+static inline void debugfs_remove_domain_dir(struct irq_domain *d) { }
+#endif
+
+static const char *irqchip_fwnode_get_name(const struct fwnode_handle *fwnode)
+{
+	struct irqchip_fwid *fwid = container_of(fwnode, struct irqchip_fwid, fwnode);
+
+	return fwid->name;
+}
+
+const struct fwnode_operations irqchip_fwnode_ops = {
+	.get_name = irqchip_fwnode_get_name,
+};
+EXPORT_SYMBOL_GPL(irqchip_fwnode_ops);
+
+/**
+ * __irq_domain_alloc_fwnode - Allocate a fwnode_handle suitable for
+ *                           identifying an irq domain
+ * @type:	Type of irqchip_fwnode. See linux/irqdomain.h
+ * @id:		Optional user provided id if name != NULL
+ * @name:	Optional user provided domain name
+ * @pa:		Optional user-provided physical address
+ *
+ * Allocate a struct irqchip_fwid, and return a pointer to the embedded
+ * fwnode_handle (or NULL on failure).
+ *
+ * Note: The types IRQCHIP_FWNODE_NAMED and IRQCHIP_FWNODE_NAMED_ID are
+ * solely to transport name information to irqdomain creation code. The
+ * node is not stored. For other types the pointer is kept in the irq
+ * domain struct.
+ */
+struct fwnode_handle *__irq_domain_alloc_fwnode(unsigned int type, int id,
+						const char *name,
+						phys_addr_t *pa)
+{
+	struct irqchip_fwid *fwid;
+	char *n;
+
+	fwid = kzalloc(sizeof(*fwid), GFP_KERNEL);
+
+	switch (type) {
+	case IRQCHIP_FWNODE_NAMED:
+		n = kasprintf(GFP_KERNEL, "%s", name);
+		break;
+	case IRQCHIP_FWNODE_NAMED_ID:
+		n = kasprintf(GFP_KERNEL, "%s-%d", name, id);
+		break;
+	default:
+		n = kasprintf(GFP_KERNEL, "irqchip@%pa", pa);
+		break;
+	}
+
+	if (!fwid || !n) {
+		kfree(fwid);
+		kfree(n);
+		return NULL;
+	}
+
+	fwid->type = type;
+	fwid->name = n;
+	fwid->pa = pa;
+	fwnode_init(&fwid->fwnode, &irqchip_fwnode_ops);
+	return &fwid->fwnode;
+}
+EXPORT_SYMBOL_GPL(__irq_domain_alloc_fwnode);
+
+/**
+ * irq_domain_free_fwnode - Free a non-OF-backed fwnode_handle
+ *
+ * Free a fwnode_handle allocated with irq_domain_alloc_fwnode.
+ */
+void irq_domain_free_fwnode(struct fwnode_handle *fwnode)
+{
+	struct irqchip_fwid *fwid;
+
+	if (WARN_ON(!is_fwnode_irqchip(fwnode)))
+		return;
+
+	fwid = container_of(fwnode, struct irqchip_fwid, fwnode);
+	kfree(fwid->name);
+	kfree(fwid);
+}
+EXPORT_SYMBOL_GPL(irq_domain_free_fwnode);
+
+static struct irq_domain *__irq_domain_create(struct fwnode_handle *fwnode,
+					      unsigned int size,
+					      irq_hw_number_t hwirq_max,
+					      int direct_max,
+					      const struct irq_domain_ops *ops,
+					      void *host_data)
+{
+	struct irqchip_fwid *fwid;
+	struct irq_domain *domain;
+
+	static atomic_t unknown_domains;
+
+	if (WARN_ON((size && direct_max) ||
+		    (!IS_ENABLED(CONFIG_IRQ_DOMAIN_NOMAP) && direct_max) ||
+		    (direct_max && (direct_max != hwirq_max))))
+		return NULL;
+
+	domain = kzalloc_node(struct_size(domain, revmap, size),
+			      GFP_KERNEL, of_node_to_nid(to_of_node(fwnode)));
+	if (!domain)
+		return NULL;
+
+	if (is_fwnode_irqchip(fwnode)) {
+		fwid = container_of(fwnode, struct irqchip_fwid, fwnode);
+
+		switch (fwid->type) {
+		case IRQCHIP_FWNODE_NAMED:
+		case IRQCHIP_FWNODE_NAMED_ID:
+			domain->fwnode = fwnode;
+			domain->name = kstrdup(fwid->name, GFP_KERNEL);
+			if (!domain->name) {
+				kfree(domain);
+				return NULL;
+			}
+			domain->flags |= IRQ_DOMAIN_NAME_ALLOCATED;
+			break;
+		default:
+			domain->fwnode = fwnode;
+			domain->name = fwid->name;
+			break;
+		}
+	} else if (is_of_node(fwnode) || is_acpi_device_node(fwnode) ||
+		   is_software_node(fwnode)) {
+		char *name;
+
+		/*
+		 * fwnode paths contain '/', which debugfs is legitimately
+		 * unhappy about. Replace them with ':', which does
+		 * the trick and is not as offensive as '\'...
+		 */
+		name = kasprintf(GFP_KERNEL, "%pfw", fwnode);
+		if (!name) {
+			kfree(domain);
+			return NULL;
+		}
+
+		strreplace(name, '/', ':');
+
+		domain->name = name;
+		domain->fwnode = fwnode;
+		domain->flags |= IRQ_DOMAIN_NAME_ALLOCATED;
+	}
+
+	if (!domain->name) {
+		if (fwnode)
+			pr_err("Invalid fwnode type for irqdomain\n");
+		domain->name = kasprintf(GFP_KERNEL, "unknown-%d",
+					 atomic_inc_return(&unknown_domains));
+		if (!domain->name) {
+			kfree(domain);
+			return NULL;
+		}
+		domain->flags |= IRQ_DOMAIN_NAME_ALLOCATED;
+	}
+
+	fwnode_handle_get(fwnode);
+	fwnode_dev_initialized(fwnode, true);
+
+	/* Fill structure */
+	INIT_RADIX_TREE(&domain->revmap_tree, GFP_KERNEL);
+	mutex_init(&domain->revmap_mutex);
+	domain->ops = ops;
+	domain->host_data = host_data;
+	domain->hwirq_max = hwirq_max;
+
+	if (direct_max) {
+		domain->flags |= IRQ_DOMAIN_FLAG_NO_MAP;
+	}
+
+	domain->revmap_size = size;
+
+	irq_domain_check_hierarchy(domain);
+
+	return domain;
+}
+
+static void __irq_domain_publish(struct irq_domain *domain)
+{
+	mutex_lock(&irq_domain_mutex);
+	debugfs_add_domain_dir(domain);
+	list_add(&domain->link, &irq_domain_list);
+	mutex_unlock(&irq_domain_mutex);
+
+	pr_debug("Added domain %s\n", domain->name);
+}
+
+/**
+ * __irq_domain_add() - Allocate a new irq_domain data structure
+ * @fwnode: firmware node for the interrupt controller
+ * @size: Size of linear map; 0 for radix mapping only
+ * @hwirq_max: Maximum number of interrupts supported by controller
+ * @direct_max: Maximum value of direct maps; Use ~0 for no limit; 0 for no
+ *              direct mapping
+ * @ops: domain callbacks
+ * @host_data: Controller private data pointer
+ *
+ * Allocates and initializes an irq_domain structure.
+ * Returns pointer to IRQ domain, or NULL on failure.
+ */
+struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, unsigned int size,
+				    irq_hw_number_t hwirq_max, int direct_max,
+				    const struct irq_domain_ops *ops,
+				    void *host_data)
+{
+	struct irq_domain *domain;
+
+	domain = __irq_domain_create(fwnode, size, hwirq_max, direct_max,
+				     ops, host_data);
+	if (domain)
+		__irq_domain_publish(domain);
+
+	return domain;
+}
+EXPORT_SYMBOL_GPL(__irq_domain_add);
+
+/**
+ * irq_domain_remove() - Remove an irq domain.
+ * @domain: domain to remove
+ *
+ * This routine is used to remove an irq domain. The caller must ensure
+ * that all mappings within the domain have been disposed of prior to
+ * use, depending on the revmap type.
+ */
+void irq_domain_remove(struct irq_domain *domain)
+{
+	mutex_lock(&irq_domain_mutex);
+	debugfs_remove_domain_dir(domain);
+
+	WARN_ON(!radix_tree_empty(&domain->revmap_tree));
+
+	list_del(&domain->link);
+
+	/*
+	 * If the going away domain is the default one, reset it.
+	 */
+	if (unlikely(irq_default_domain == domain))
+		irq_set_default_host(NULL);
+
+	mutex_unlock(&irq_domain_mutex);
+
+	pr_debug("Removed domain %s\n", domain->name);
+
+	fwnode_dev_initialized(domain->fwnode, false);
+	fwnode_handle_put(domain->fwnode);
+	if (domain->flags & IRQ_DOMAIN_NAME_ALLOCATED)
+		kfree(domain->name);
+	kfree(domain);
+}
+EXPORT_SYMBOL_GPL(irq_domain_remove);
+
+void irq_domain_update_bus_token(struct irq_domain *domain,
+				 enum irq_domain_bus_token bus_token)
+{
+	char *name;
+
+	if (domain->bus_token == bus_token)
+		return;
+
+	mutex_lock(&irq_domain_mutex);
+
+	domain->bus_token = bus_token;
+
+	name = kasprintf(GFP_KERNEL, "%s-%d", domain->name, bus_token);
+	if (!name) {
+		mutex_unlock(&irq_domain_mutex);
+		return;
+	}
+
+	debugfs_remove_domain_dir(domain);
+
+	if (domain->flags & IRQ_DOMAIN_NAME_ALLOCATED)
+		kfree(domain->name);
+	else
+		domain->flags |= IRQ_DOMAIN_NAME_ALLOCATED;
+
+	domain->name = name;
+	debugfs_add_domain_dir(domain);
+
+	mutex_unlock(&irq_domain_mutex);
+}
+EXPORT_SYMBOL_GPL(irq_domain_update_bus_token);
+
+/**
+ * irq_domain_create_simple() - Register an irq_domain and optionally map a range of irqs
+ * @fwnode: firmware node for the interrupt controller
+ * @size: total number of irqs in mapping
+ * @first_irq: first number of irq block assigned to the domain,
+ *	pass zero to assign irqs on-the-fly. If first_irq is non-zero, then
+ *	pre-map all of the irqs in the domain to virqs starting at first_irq.
+ * @ops: domain callbacks
+ * @host_data: Controller private data pointer
+ *
+ * Allocates an irq_domain, and optionally if first_irq is positive then also
+ * allocate irq_descs and map all of the hwirqs to virqs starting at first_irq.
+ *
+ * This is intended to implement the expected behaviour for most
+ * interrupt controllers. If device tree is used, then first_irq will be 0 and
+ * irqs get mapped dynamically on the fly. However, if the controller requires
+ * static virq assignments (non-DT boot) then it will set that up correctly.
+ */
+struct irq_domain *irq_domain_create_simple(struct fwnode_handle *fwnode,
+					    unsigned int size,
+					    unsigned int first_irq,
+					    const struct irq_domain_ops *ops,
+					    void *host_data)
+{
+	struct irq_domain *domain;
+
+	domain = __irq_domain_add(fwnode, size, size, 0, ops, host_data);
+	if (!domain)
+		return NULL;
+
+	if (first_irq > 0) {
+		if (IS_ENABLED(CONFIG_SPARSE_IRQ)) {
+			/* attempt to allocated irq_descs */
+			int rc = irq_alloc_descs(first_irq, first_irq, size,
+						 of_node_to_nid(to_of_node(fwnode)));
+			if (rc < 0)
+				pr_info("Cannot allocate irq_descs @ IRQ%d, assuming pre-allocated\n",
+					first_irq);
+		}
+		irq_domain_associate_many(domain, first_irq, 0, size);
+	}
+
+	return domain;
+}
+EXPORT_SYMBOL_GPL(irq_domain_create_simple);
+
+/**
+ * irq_domain_add_legacy() - Allocate and register a legacy revmap irq_domain.
+ * @of_node: pointer to interrupt controller's device tree node.
+ * @size: total number of irqs in legacy mapping
+ * @first_irq: first number of irq block assigned to the domain
+ * @first_hwirq: first hwirq number to use for the translation. Should normally
+ *               be '0', but a positive integer can be used if the effective
+ *               hwirqs numbering does not begin at zero.
+ * @ops: map/unmap domain callbacks
+ * @host_data: Controller private data pointer
+ *
+ * Note: the map() callback will be called before this function returns
+ * for all legacy interrupts except 0 (which is always the invalid irq for
+ * a legacy controller).
+ */
+struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
+					 unsigned int size,
+					 unsigned int first_irq,
+					 irq_hw_number_t first_hwirq,
+					 const struct irq_domain_ops *ops,
+					 void *host_data)
+{
+	return irq_domain_create_legacy(of_node_to_fwnode(of_node), size,
+					first_irq, first_hwirq, ops, host_data);
+}
+EXPORT_SYMBOL_GPL(irq_domain_add_legacy);
+
+struct irq_domain *irq_domain_create_legacy(struct fwnode_handle *fwnode,
+					 unsigned int size,
+					 unsigned int first_irq,
+					 irq_hw_number_t first_hwirq,
+					 const struct irq_domain_ops *ops,
+					 void *host_data)
+{
+	struct irq_domain *domain;
+
+	domain = __irq_domain_add(fwnode, first_hwirq + size, first_hwirq + size, 0, ops, host_data);
+	if (domain)
+		irq_domain_associate_many(domain, first_irq, first_hwirq, size);
+
+	return domain;
+}
+EXPORT_SYMBOL_GPL(irq_domain_create_legacy);
+
+/**
+ * irq_find_matching_fwspec() - Locates a domain for a given fwspec
+ * @fwspec: FW specifier for an interrupt
+ * @bus_token: domain-specific data
+ */
+struct irq_domain *irq_find_matching_fwspec(struct irq_fwspec *fwspec,
+					    enum irq_domain_bus_token bus_token)
+{
+	struct irq_domain *h, *found = NULL;
+	struct fwnode_handle *fwnode = fwspec->fwnode;
+	int rc;
+
+	/* We might want to match the legacy controller last since
+	 * it might potentially be set to match all interrupts in
+	 * the absence of a device node. This isn't a problem so far
+	 * yet though...
+	 *
+	 * bus_token == DOMAIN_BUS_ANY matches any domain, any other
+	 * values must generate an exact match for the domain to be
+	 * selected.
+	 */
+	mutex_lock(&irq_domain_mutex);
+	list_for_each_entry(h, &irq_domain_list, link) {
+		if (h->ops->select && fwspec->param_count)
+			rc = h->ops->select(h, fwspec, bus_token);
+		else if (h->ops->match)
+			rc = h->ops->match(h, to_of_node(fwnode), bus_token);
+		else
+			rc = ((fwnode != NULL) && (h->fwnode == fwnode) &&
+			      ((bus_token == DOMAIN_BUS_ANY) ||
+			       (h->bus_token == bus_token)));
+
+		if (rc) {
+			found = h;
+			break;
+		}
+	}
+	mutex_unlock(&irq_domain_mutex);
+	return found;
+}
+EXPORT_SYMBOL_GPL(irq_find_matching_fwspec);
+
+/**
+ * irq_domain_check_msi_remap - Check whether all MSI irq domains implement
+ * IRQ remapping
+ *
+ * Return: false if any MSI irq domain does not support IRQ remapping,
+ * true otherwise (including if there is no MSI irq domain)
+ */
+bool irq_domain_check_msi_remap(void)
+{
+	struct irq_domain *h;
+	bool ret = true;
+
+	mutex_lock(&irq_domain_mutex);
+	list_for_each_entry(h, &irq_domain_list, link) {
+		if (irq_domain_is_msi(h) &&
+		    !irq_domain_hierarchical_is_msi_remap(h)) {
+			ret = false;
+			break;
+		}
+	}
+	mutex_unlock(&irq_domain_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(irq_domain_check_msi_remap);
+
+/**
+ * irq_set_default_host() - Set a "default" irq domain
+ * @domain: default domain pointer
+ *
+ * For convenience, it's possible to set a "default" domain that will be used
+ * whenever NULL is passed to irq_create_mapping(). It makes life easier for
+ * platforms that want to manipulate a few hard coded interrupt numbers that
+ * aren't properly represented in the device-tree.
+ */
+void irq_set_default_host(struct irq_domain *domain)
+{
+	pr_debug("Default domain set to @0x%p\n", domain);
+
+	irq_default_domain = domain;
+}
+EXPORT_SYMBOL_GPL(irq_set_default_host);
+
+/**
+ * irq_get_default_host() - Retrieve the "default" irq domain
+ *
+ * Returns: the default domain, if any.
+ *
+ * Modern code should never use this. This should only be used on
+ * systems that cannot implement a firmware->fwnode mapping (which
+ * both DT and ACPI provide).
+ */
+struct irq_domain *irq_get_default_host(void)
+{
+	return irq_default_domain;
+}
+EXPORT_SYMBOL_GPL(irq_get_default_host);
+
+static bool irq_domain_is_nomap(struct irq_domain *domain)
+{
+	return IS_ENABLED(CONFIG_IRQ_DOMAIN_NOMAP) &&
+	       (domain->flags & IRQ_DOMAIN_FLAG_NO_MAP);
+}
+
+static void irq_domain_clear_mapping(struct irq_domain *domain,
+				     irq_hw_number_t hwirq)
+{
+	if (irq_domain_is_nomap(domain))
+		return;
+
+	mutex_lock(&domain->revmap_mutex);
+	if (hwirq < domain->revmap_size)
+		rcu_assign_pointer(domain->revmap[hwirq], NULL);
+	else
+		radix_tree_delete(&domain->revmap_tree, hwirq);
+	mutex_unlock(&domain->revmap_mutex);
+}
+
+static void irq_domain_set_mapping(struct irq_domain *domain,
+				   irq_hw_number_t hwirq,
+				   struct irq_data *irq_data)
+{
+	if (irq_domain_is_nomap(domain))
+		return;
+
+	mutex_lock(&domain->revmap_mutex);
+	if (hwirq < domain->revmap_size)
+		rcu_assign_pointer(domain->revmap[hwirq], irq_data);
+	else
+		radix_tree_insert(&domain->revmap_tree, hwirq, irq_data);
+	mutex_unlock(&domain->revmap_mutex);
+}
+
+static void irq_domain_disassociate(struct irq_domain *domain, unsigned int irq)
+{
+	struct irq_data *irq_data = irq_get_irq_data(irq);
+	irq_hw_number_t hwirq;
+
+	if (WARN(!irq_data || irq_data->domain != domain,
+		 "virq%i doesn't exist; cannot disassociate\n", irq))
+		return;
+
+	hwirq = irq_data->hwirq;
+
+	mutex_lock(&irq_domain_mutex);
+
+	irq_set_status_flags(irq, IRQ_NOREQUEST);
+
+	/* remove chip and handler */
+	irq_set_chip_and_handler(irq, NULL, NULL);
+
+	/* Make sure it's completed */
+	synchronize_irq(irq);
+
+	/* Tell the PIC about it */
+	if (domain->ops->unmap)
+		domain->ops->unmap(domain, irq);
+	smp_mb();
+
+	irq_data->domain = NULL;
+	irq_data->hwirq = 0;
+	domain->mapcount--;
+
+	/* Clear reverse map for this hwirq */
+	irq_domain_clear_mapping(domain, hwirq);
+
+	mutex_unlock(&irq_domain_mutex);
+}
+
+static int irq_domain_associate_locked(struct irq_domain *domain, unsigned int virq,
+				       irq_hw_number_t hwirq)
+{
+	struct irq_data *irq_data = irq_get_irq_data(virq);
+	int ret;
+
+	if (WARN(hwirq >= domain->hwirq_max,
+		 "error: hwirq 0x%x is too large for %s\n", (int)hwirq, domain->name))
+		return -EINVAL;
+	if (WARN(!irq_data, "error: virq%i is not allocated", virq))
+		return -EINVAL;
+	if (WARN(irq_data->domain, "error: virq%i is already associated", virq))
+		return -EINVAL;
+
+	irq_data->hwirq = hwirq;
+	irq_data->domain = domain;
+	if (domain->ops->map) {
+		ret = domain->ops->map(domain, virq, hwirq);
+		if (ret != 0) {
+			/*
+			 * If map() returns -EPERM, this interrupt is protected
+			 * by the firmware or some other service and shall not
+			 * be mapped. Don't bother telling the user about it.
+			 */
+			if (ret != -EPERM) {
+				pr_info("%s didn't like hwirq-0x%lx to VIRQ%i mapping (rc=%d)\n",
+				       domain->name, hwirq, virq, ret);
+			}
+			irq_data->domain = NULL;
+			irq_data->hwirq = 0;
+			return ret;
+		}
+
+		/* If not already assigned, give the domain the chip's name */
+		if (!domain->name && irq_data->chip)
+			domain->name = irq_data->chip->name;
+	}
+
+	domain->mapcount++;
+	irq_domain_set_mapping(domain, hwirq, irq_data);
+
+	irq_clear_status_flags(virq, IRQ_NOREQUEST);
+
+	return 0;
+}
+
+int irq_domain_associate(struct irq_domain *domain, unsigned int virq,
+			 irq_hw_number_t hwirq)
+{
+	int ret;
+
+	mutex_lock(&irq_domain_mutex);
+	ret = irq_domain_associate_locked(domain, virq, hwirq);
+	mutex_unlock(&irq_domain_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(irq_domain_associate);
+
+void irq_domain_associate_many(struct irq_domain *domain, unsigned int irq_base,
+			       irq_hw_number_t hwirq_base, int count)
+{
+	struct device_node *of_node;
+	int i;
+
+	of_node = irq_domain_get_of_node(domain);
+	pr_debug("%s(%s, irqbase=%i, hwbase=%i, count=%i)\n", __func__,
+		of_node_full_name(of_node), irq_base, (int)hwirq_base, count);
+
+	for (i = 0; i < count; i++) {
+		irq_domain_associate(domain, irq_base + i, hwirq_base + i);
+	}
+}
+EXPORT_SYMBOL_GPL(irq_domain_associate_many);
+
+#ifdef CONFIG_IRQ_DOMAIN_NOMAP
+/**
+ * irq_create_direct_mapping() - Allocate an irq for direct mapping
+ * @domain: domain to allocate the irq for or NULL for default domain
+ *
+ * This routine is used for irq controllers which can choose the hardware
+ * interrupt numbers they generate. In such a case it's simplest to use
+ * the linux irq as the hardware interrupt number. It still uses the linear
+ * or radix tree to store the mapping, but the irq controller can optimize
+ * the revmap path by using the hwirq directly.
+ */
+unsigned int irq_create_direct_mapping(struct irq_domain *domain)
+{
+	struct device_node *of_node;
+	unsigned int virq;
+
+	if (domain == NULL)
+		domain = irq_default_domain;
+
+	of_node = irq_domain_get_of_node(domain);
+	virq = irq_alloc_desc_from(1, of_node_to_nid(of_node));
+	if (!virq) {
+		pr_debug("create_direct virq allocation failed\n");
+		return 0;
+	}
+	if (virq >= domain->hwirq_max) {
+		pr_err("ERROR: no free irqs available below %lu maximum\n",
+			domain->hwirq_max);
+		irq_free_desc(virq);
+		return 0;
+	}
+	pr_debug("create_direct obtained virq %d\n", virq);
+
+	if (irq_domain_associate(domain, virq, virq)) {
+		irq_free_desc(virq);
+		return 0;
+	}
+
+	return virq;
+}
+EXPORT_SYMBOL_GPL(irq_create_direct_mapping);
+#endif
+
+static unsigned int irq_create_mapping_affinity_locked(struct irq_domain *domain,
+						       irq_hw_number_t hwirq,
+						       const struct irq_affinity_desc *affinity)
+{
+	struct device_node *of_node = irq_domain_get_of_node(domain);
+	int virq;
+
+	pr_debug("irq_create_mapping(0x%p, 0x%lx)\n", domain, hwirq);
+
+	/* Allocate a virtual interrupt number */
+	virq = irq_domain_alloc_descs(-1, 1, hwirq, of_node_to_nid(of_node),
+				      affinity);
+	if (virq <= 0) {
+		pr_debug("-> virq allocation failed\n");
+		return 0;
+	}
+
+	if (irq_domain_associate_locked(domain, virq, hwirq)) {
+		irq_free_desc(virq);
+		return 0;
+	}
+
+	pr_debug("irq %lu on domain %s mapped to virtual irq %u\n",
+		hwirq, of_node_full_name(of_node), virq);
+
+	return virq;
+}
+
+/**
+ * irq_create_mapping_affinity() - Map a hardware interrupt into linux irq space
+ * @domain: domain owning this hardware interrupt or NULL for default domain
+ * @hwirq: hardware irq number in that domain space
+ * @affinity: irq affinity
+ *
+ * Only one mapping per hardware interrupt is permitted. Returns a linux
+ * irq number.
+ * If the sense/trigger is to be specified, set_irq_type() should be called
+ * on the number returned from that call.
+ */
+unsigned int irq_create_mapping_affinity(struct irq_domain *domain,
+					 irq_hw_number_t hwirq,
+					 const struct irq_affinity_desc *affinity)
+{
+	int virq;
+
+	/* Look for default domain if necessary */
+	if (domain == NULL)
+		domain = irq_default_domain;
+	if (domain == NULL) {
+		WARN(1, "%s(, %lx) called with NULL domain\n", __func__, hwirq);
+		return 0;
+	}
+
+	mutex_lock(&irq_domain_mutex);
+
+	/* Check if mapping already exists */
+	virq = irq_find_mapping(domain, hwirq);
+	if (virq) {
+		pr_debug("existing mapping on virq %d\n", virq);
+		goto out;
+	}
+
+	virq = irq_create_mapping_affinity_locked(domain, hwirq, affinity);
+out:
+	mutex_unlock(&irq_domain_mutex);
+
+	return virq;
+}
+EXPORT_SYMBOL_GPL(irq_create_mapping_affinity);
+
+static int irq_domain_translate(struct irq_domain *d,
+				struct irq_fwspec *fwspec,
+				irq_hw_number_t *hwirq, unsigned int *type)
+{
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+	if (d->ops->translate)
+		return d->ops->translate(d, fwspec, hwirq, type);
+#endif
+	if (d->ops->xlate)
+		return d->ops->xlate(d, to_of_node(fwspec->fwnode),
+				     fwspec->param, fwspec->param_count,
+				     hwirq, type);
+
+	/* If domain has no translation, then we assume interrupt line */
+	*hwirq = fwspec->param[0];
+	return 0;
+}
+
+void of_phandle_args_to_fwspec(struct device_node *np, const u32 *args,
+			       unsigned int count, struct irq_fwspec *fwspec)
+{
+	int i;
+
+	fwspec->fwnode = of_node_to_fwnode(np);
+	fwspec->param_count = count;
+
+	for (i = 0; i < count; i++)
+		fwspec->param[i] = args[i];
+}
+EXPORT_SYMBOL_GPL(of_phandle_args_to_fwspec);
+
+unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec)
+{
+	struct irq_domain *domain;
+	struct irq_data *irq_data;
+	irq_hw_number_t hwirq;
+	unsigned int type = IRQ_TYPE_NONE;
+	int virq;
+
+	if (fwspec->fwnode) {
+		domain = irq_find_matching_fwspec(fwspec, DOMAIN_BUS_WIRED);
+		if (!domain)
+			domain = irq_find_matching_fwspec(fwspec, DOMAIN_BUS_ANY);
+	} else {
+		domain = irq_default_domain;
+	}
+
+	if (!domain) {
+		pr_warn("no irq domain found for %s !\n",
+			of_node_full_name(to_of_node(fwspec->fwnode)));
+		return 0;
+	}
+
+	if (irq_domain_translate(domain, fwspec, &hwirq, &type))
+		return 0;
+
+	/*
+	 * WARN if the irqchip returns a type with bits
+	 * outside the sense mask set and clear these bits.
+	 */
+	if (WARN_ON(type & ~IRQ_TYPE_SENSE_MASK))
+		type &= IRQ_TYPE_SENSE_MASK;
+
+	mutex_lock(&irq_domain_mutex);
+
+	/*
+	 * If we've already configured this interrupt,
+	 * don't do it again, or hell will break loose.
+	 */
+	virq = irq_find_mapping(domain, hwirq);
+	if (virq) {
+		/*
+		 * If the trigger type is not specified or matches the
+		 * current trigger type then we are done so return the
+		 * interrupt number.
+		 */
+		if (type == IRQ_TYPE_NONE || type == irq_get_trigger_type(virq))
+			goto out;
+
+		/*
+		 * If the trigger type has not been set yet, then set
+		 * it now and return the interrupt number.
+		 */
+		if (irq_get_trigger_type(virq) == IRQ_TYPE_NONE) {
+			irq_data = irq_get_irq_data(virq);
+			if (!irq_data) {
+				virq = 0;
+				goto out;
+			}
+
+			irqd_set_trigger_type(irq_data, type);
+			goto out;
+		}
+
+		pr_warn("type mismatch, failed to map hwirq-%lu for %s!\n",
+			hwirq, of_node_full_name(to_of_node(fwspec->fwnode)));
+		virq = 0;
+		goto out;
+	}
+
+	if (irq_domain_is_hierarchy(domain)) {
+		virq = irq_domain_alloc_irqs_locked(domain, -1, 1, NUMA_NO_NODE,
+						    fwspec, false, NULL);
+		if (virq <= 0) {
+			virq = 0;
+			goto out;
+		}
+	} else {
+		/* Create mapping */
+		virq = irq_create_mapping_affinity_locked(domain, hwirq, NULL);
+		if (!virq)
+			goto out;
+	}
+
+	irq_data = irq_get_irq_data(virq);
+	if (WARN_ON(!irq_data)) {
+		virq = 0;
+		goto out;
+	}
+
+	/* Store trigger type */
+	irqd_set_trigger_type(irq_data, type);
+out:
+	mutex_unlock(&irq_domain_mutex);
+
+	return virq;
+}
+EXPORT_SYMBOL_GPL(irq_create_fwspec_mapping);
+
+unsigned int irq_create_of_mapping(struct of_phandle_args *irq_data)
+{
+	struct irq_fwspec fwspec;
+
+	of_phandle_args_to_fwspec(irq_data->np, irq_data->args,
+				  irq_data->args_count, &fwspec);
+
+	return irq_create_fwspec_mapping(&fwspec);
+}
+EXPORT_SYMBOL_GPL(irq_create_of_mapping);
+
+/**
+ * irq_dispose_mapping() - Unmap an interrupt
+ * @virq: linux irq number of the interrupt to unmap
+ */
+void irq_dispose_mapping(unsigned int virq)
+{
+	struct irq_data *irq_data = irq_get_irq_data(virq);
+	struct irq_domain *domain;
+
+	if (!virq || !irq_data)
+		return;
+
+	domain = irq_data->domain;
+	if (WARN_ON(domain == NULL))
+		return;
+
+	if (irq_domain_is_hierarchy(domain)) {
+		irq_domain_free_irqs(virq, 1);
+	} else {
+		irq_domain_disassociate(domain, virq);
+		irq_free_desc(virq);
+	}
+}
+EXPORT_SYMBOL_GPL(irq_dispose_mapping);
+
+/**
+ * __irq_resolve_mapping() - Find a linux irq from a hw irq number.
+ * @domain: domain owning this hardware interrupt
+ * @hwirq: hardware irq number in that domain space
+ * @irq: optional pointer to return the Linux irq if required
+ *
+ * Returns the interrupt descriptor.
+ */
+struct irq_desc *__irq_resolve_mapping(struct irq_domain *domain,
+				       irq_hw_number_t hwirq,
+				       unsigned int *irq)
+{
+	struct irq_desc *desc = NULL;
+	struct irq_data *data;
+
+	/* Look for default domain if necessary */
+	if (domain == NULL)
+		domain = irq_default_domain;
+	if (domain == NULL)
+		return desc;
+
+	if (irq_domain_is_nomap(domain)) {
+		if (hwirq < domain->hwirq_max) {
+			data = irq_domain_get_irq_data(domain, hwirq);
+			if (data && data->hwirq == hwirq)
+				desc = irq_data_to_desc(data);
+			if (irq && desc)
+				*irq = hwirq;
+		}
+
+		return desc;
+	}
+
+	rcu_read_lock();
+	/* Check if the hwirq is in the linear revmap. */
+	if (hwirq < domain->revmap_size)
+		data = rcu_dereference(domain->revmap[hwirq]);
+	else
+		data = radix_tree_lookup(&domain->revmap_tree, hwirq);
+
+	if (likely(data)) {
+		desc = irq_data_to_desc(data);
+		if (irq)
+			*irq = data->irq;
+	}
+
+	rcu_read_unlock();
+	return desc;
+}
+EXPORT_SYMBOL_GPL(__irq_resolve_mapping);
+
+/**
+ * irq_domain_xlate_onecell() - Generic xlate for direct one cell bindings
+ *
+ * Device Tree IRQ specifier translation function which works with one cell
+ * bindings where the cell value maps directly to the hwirq number.
+ */
+int irq_domain_xlate_onecell(struct irq_domain *d, struct device_node *ctrlr,
+			     const u32 *intspec, unsigned int intsize,
+			     unsigned long *out_hwirq, unsigned int *out_type)
+{
+	if (WARN_ON(intsize < 1))
+		return -EINVAL;
+	*out_hwirq = intspec[0];
+	*out_type = IRQ_TYPE_NONE;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_domain_xlate_onecell);
+
+/**
+ * irq_domain_xlate_twocell() - Generic xlate for direct two cell bindings
+ *
+ * Device Tree IRQ specifier translation function which works with two cell
+ * bindings where the cell values map directly to the hwirq number
+ * and linux irq flags.
+ */
+int irq_domain_xlate_twocell(struct irq_domain *d, struct device_node *ctrlr,
+			const u32 *intspec, unsigned int intsize,
+			irq_hw_number_t *out_hwirq, unsigned int *out_type)
+{
+	struct irq_fwspec fwspec;
+
+	of_phandle_args_to_fwspec(ctrlr, intspec, intsize, &fwspec);
+	return irq_domain_translate_twocell(d, &fwspec, out_hwirq, out_type);
+}
+EXPORT_SYMBOL_GPL(irq_domain_xlate_twocell);
+
+/**
+ * irq_domain_xlate_onetwocell() - Generic xlate for one or two cell bindings
+ *
+ * Device Tree IRQ specifier translation function which works with either one
+ * or two cell bindings where the cell values map directly to the hwirq number
+ * and linux irq flags.
+ *
+ * Note: don't use this function unless your interrupt controller explicitly
+ * supports both one and two cell bindings.  For the majority of controllers
+ * the _onecell() or _twocell() variants above should be used.
+ */
+int irq_domain_xlate_onetwocell(struct irq_domain *d,
+				struct device_node *ctrlr,
+				const u32 *intspec, unsigned int intsize,
+				unsigned long *out_hwirq, unsigned int *out_type)
+{
+	if (WARN_ON(intsize < 1))
+		return -EINVAL;
+	*out_hwirq = intspec[0];
+	if (intsize > 1)
+		*out_type = intspec[1] & IRQ_TYPE_SENSE_MASK;
+	else
+		*out_type = IRQ_TYPE_NONE;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_domain_xlate_onetwocell);
+
+const struct irq_domain_ops irq_domain_simple_ops = {
+	.xlate = irq_domain_xlate_onetwocell,
+};
+EXPORT_SYMBOL_GPL(irq_domain_simple_ops);
+
+/**
+ * irq_domain_translate_onecell() - Generic translate for direct one cell
+ * bindings
+ */
+int irq_domain_translate_onecell(struct irq_domain *d,
+				 struct irq_fwspec *fwspec,
+				 unsigned long *out_hwirq,
+				 unsigned int *out_type)
+{
+	if (WARN_ON(fwspec->param_count < 1))
+		return -EINVAL;
+	*out_hwirq = fwspec->param[0];
+	*out_type = IRQ_TYPE_NONE;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_domain_translate_onecell);
+
+/**
+ * irq_domain_translate_twocell() - Generic translate for direct two cell
+ * bindings
+ *
+ * Device Tree IRQ specifier translation function which works with two cell
+ * bindings where the cell values map directly to the hwirq number
+ * and linux irq flags.
+ */
+int irq_domain_translate_twocell(struct irq_domain *d,
+				 struct irq_fwspec *fwspec,
+				 unsigned long *out_hwirq,
+				 unsigned int *out_type)
+{
+	if (WARN_ON(fwspec->param_count < 2))
+		return -EINVAL;
+	*out_hwirq = fwspec->param[0];
+	*out_type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_domain_translate_twocell);
+
+int irq_domain_alloc_descs(int virq, unsigned int cnt, irq_hw_number_t hwirq,
+			   int node, const struct irq_affinity_desc *affinity)
+{
+	unsigned int hint;
+
+	if (virq >= 0) {
+		virq = __irq_alloc_descs(virq, virq, cnt, node, THIS_MODULE,
+					 affinity);
+	} else {
+		hint = hwirq % nr_irqs;
+		if (hint == 0)
+			hint++;
+		virq = __irq_alloc_descs(-1, hint, cnt, node, THIS_MODULE,
+					 affinity);
+		if (virq <= 0 && hint > 1) {
+			virq = __irq_alloc_descs(-1, 1, cnt, node, THIS_MODULE,
+						 affinity);
+		}
+	}
+
+	return virq;
+}
+
+/**
+ * irq_domain_reset_irq_data - Clear hwirq, chip and chip_data in @irq_data
+ * @irq_data:	The pointer to irq_data
+ */
+void irq_domain_reset_irq_data(struct irq_data *irq_data)
+{
+	irq_data->hwirq = 0;
+	irq_data->chip = &no_irq_chip;
+	irq_data->chip_data = NULL;
+}
+EXPORT_SYMBOL_GPL(irq_domain_reset_irq_data);
+
+#ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+/**
+ * irq_domain_create_hierarchy - Add a irqdomain into the hierarchy
+ * @parent:	Parent irq domain to associate with the new domain
+ * @flags:	Irq domain flags associated to the domain
+ * @size:	Size of the domain. See below
+ * @fwnode:	Optional fwnode of the interrupt controller
+ * @ops:	Pointer to the interrupt domain callbacks
+ * @host_data:	Controller private data pointer
+ *
+ * If @size is 0 a tree domain is created, otherwise a linear domain.
+ *
+ * If successful the parent is associated to the new domain and the
+ * domain flags are set.
+ * Returns pointer to IRQ domain, or NULL on failure.
+ */
+struct irq_domain *irq_domain_create_hierarchy(struct irq_domain *parent,
+					    unsigned int flags,
+					    unsigned int size,
+					    struct fwnode_handle *fwnode,
+					    const struct irq_domain_ops *ops,
+					    void *host_data)
+{
+	struct irq_domain *domain;
+
+	if (size)
+		domain = __irq_domain_create(fwnode, size, size, 0, ops, host_data);
+	else
+		domain = __irq_domain_create(fwnode, 0, ~0, 0, ops, host_data);
+
+	if (domain) {
+		domain->parent = parent;
+		domain->flags |= flags;
+
+		__irq_domain_publish(domain);
+	}
+
+	return domain;
+}
+EXPORT_SYMBOL_GPL(irq_domain_create_hierarchy);
+
+static void irq_domain_insert_irq(int virq)
+{
+	struct irq_data *data;
+
+	for (data = irq_get_irq_data(virq); data; data = data->parent_data) {
+		struct irq_domain *domain = data->domain;
+
+		domain->mapcount++;
+		irq_domain_set_mapping(domain, data->hwirq, data);
+
+		/* If not already assigned, give the domain the chip's name */
+		if (!domain->name && data->chip)
+			domain->name = data->chip->name;
+	}
+
+	irq_clear_status_flags(virq, IRQ_NOREQUEST);
+}
+
+static void irq_domain_remove_irq(int virq)
+{
+	struct irq_data *data;
+
+	irq_set_status_flags(virq, IRQ_NOREQUEST);
+	irq_set_chip_and_handler(virq, NULL, NULL);
+	synchronize_irq(virq);
+	smp_mb();
+
+	for (data = irq_get_irq_data(virq); data; data = data->parent_data) {
+		struct irq_domain *domain = data->domain;
+		irq_hw_number_t hwirq = data->hwirq;
+
+		domain->mapcount--;
+		irq_domain_clear_mapping(domain, hwirq);
+	}
+}
+
+static struct irq_data *irq_domain_insert_irq_data(struct irq_domain *domain,
+						   struct irq_data *child)
+{
+	struct irq_data *irq_data;
+
+	irq_data = kzalloc_node(sizeof(*irq_data), GFP_KERNEL,
+				irq_data_get_node(child));
+	if (irq_data) {
+		child->parent_data = irq_data;
+		irq_data->irq = child->irq;
+		irq_data->common = child->common;
+		irq_data->domain = domain;
+	}
+
+	return irq_data;
+}
+
+static void __irq_domain_free_hierarchy(struct irq_data *irq_data)
+{
+	struct irq_data *tmp;
+
+	while (irq_data) {
+		tmp = irq_data;
+		irq_data = irq_data->parent_data;
+		kfree(tmp);
+	}
+}
+
+static void irq_domain_free_irq_data(unsigned int virq, unsigned int nr_irqs)
+{
+	struct irq_data *irq_data, *tmp;
+	int i;
+
+	for (i = 0; i < nr_irqs; i++) {
+		irq_data = irq_get_irq_data(virq + i);
+		tmp = irq_data->parent_data;
+		irq_data->parent_data = NULL;
+		irq_data->domain = NULL;
+
+		__irq_domain_free_hierarchy(tmp);
+	}
+}
+
+/**
+ * irq_domain_disconnect_hierarchy - Mark the first unused level of a hierarchy
+ * @domain:	IRQ domain from which the hierarchy is to be disconnected
+ * @virq:	IRQ number where the hierarchy is to be trimmed
+ *
+ * Marks the @virq level belonging to @domain as disconnected.
+ * Returns -EINVAL if @virq doesn't have a valid irq_data pointing
+ * to @domain.
+ *
+ * Its only use is to be able to trim levels of hierarchy that do not
+ * have any real meaning for this interrupt, and that the driver marks
+ * as such from its .alloc() callback.
+ */
+int irq_domain_disconnect_hierarchy(struct irq_domain *domain,
+				    unsigned int virq)
+{
+	struct irq_data *irqd;
+
+	irqd = irq_domain_get_irq_data(domain, virq);
+	if (!irqd)
+		return -EINVAL;
+
+	irqd->chip = ERR_PTR(-ENOTCONN);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_domain_disconnect_hierarchy);
+
+static int irq_domain_trim_hierarchy(unsigned int virq)
+{
+	struct irq_data *tail, *irqd, *irq_data;
+
+	irq_data = irq_get_irq_data(virq);
+	tail = NULL;
+
+	/* The first entry must have a valid irqchip */
+	if (!irq_data->chip || IS_ERR(irq_data->chip))
+		return -EINVAL;
+
+	/*
+	 * Validate that the irq_data chain is sane in the presence of
+	 * a hierarchy trimming marker.
+	 */
+	for (irqd = irq_data->parent_data; irqd; irq_data = irqd, irqd = irqd->parent_data) {
+		/* Can't have a valid irqchip after a trim marker */
+		if (irqd->chip && tail)
+			return -EINVAL;
+
+		/* Can't have an empty irqchip before a trim marker */
+		if (!irqd->chip && !tail)
+			return -EINVAL;
+
+		if (IS_ERR(irqd->chip)) {
+			/* Only -ENOTCONN is a valid trim marker */
+			if (PTR_ERR(irqd->chip) != -ENOTCONN)
+				return -EINVAL;
+
+			tail = irq_data;
+		}
+	}
+
+	/* No trim marker, nothing to do */
+	if (!tail)
+		return 0;
+
+	pr_info("IRQ%d: trimming hierarchy from %s\n",
+		virq, tail->parent_data->domain->name);
+
+	/* Sever the inner part of the hierarchy...  */
+	irqd = tail;
+	tail = tail->parent_data;
+	irqd->parent_data = NULL;
+	__irq_domain_free_hierarchy(tail);
+
+	return 0;
+}
+
+static int irq_domain_alloc_irq_data(struct irq_domain *domain,
+				     unsigned int virq, unsigned int nr_irqs)
+{
+	struct irq_data *irq_data;
+	struct irq_domain *parent;
+	int i;
+
+	/* The outermost irq_data is embedded in struct irq_desc */
+	for (i = 0; i < nr_irqs; i++) {
+		irq_data = irq_get_irq_data(virq + i);
+		irq_data->domain = domain;
+
+		for (parent = domain->parent; parent; parent = parent->parent) {
+			irq_data = irq_domain_insert_irq_data(parent, irq_data);
+			if (!irq_data) {
+				irq_domain_free_irq_data(virq, i + 1);
+				return -ENOMEM;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * irq_domain_get_irq_data - Get irq_data associated with @virq and @domain
+ * @domain:	domain to match
+ * @virq:	IRQ number to get irq_data
+ */
+struct irq_data *irq_domain_get_irq_data(struct irq_domain *domain,
+					 unsigned int virq)
+{
+	struct irq_data *irq_data;
+
+	for (irq_data = irq_get_irq_data(virq); irq_data;
+	     irq_data = irq_data->parent_data)
+		if (irq_data->domain == domain)
+			return irq_data;
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(irq_domain_get_irq_data);
+
+/**
+ * irq_domain_set_hwirq_and_chip - Set hwirq and irqchip of @virq at @domain
+ * @domain:	Interrupt domain to match
+ * @virq:	IRQ number
+ * @hwirq:	The hwirq number
+ * @chip:	The associated interrupt chip
+ * @chip_data:	The associated chip data
+ */
+int irq_domain_set_hwirq_and_chip(struct irq_domain *domain, unsigned int virq,
+				  irq_hw_number_t hwirq,
+				  const struct irq_chip *chip,
+				  void *chip_data)
+{
+	struct irq_data *irq_data = irq_domain_get_irq_data(domain, virq);
+
+	if (!irq_data)
+		return -ENOENT;
+
+	irq_data->hwirq = hwirq;
+	irq_data->chip = (struct irq_chip *)(chip ? chip : &no_irq_chip);
+	irq_data->chip_data = chip_data;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_domain_set_hwirq_and_chip);
+
+/**
+ * irq_domain_set_info - Set the complete data for a @virq in @domain
+ * @domain:		Interrupt domain to match
+ * @virq:		IRQ number
+ * @hwirq:		The hardware interrupt number
+ * @chip:		The associated interrupt chip
+ * @chip_data:		The associated interrupt chip data
+ * @handler:		The interrupt flow handler
+ * @handler_data:	The interrupt flow handler data
+ * @handler_name:	The interrupt handler name
+ */
+void irq_domain_set_info(struct irq_domain *domain, unsigned int virq,
+			 irq_hw_number_t hwirq, const struct irq_chip *chip,
+			 void *chip_data, irq_flow_handler_t handler,
+			 void *handler_data, const char *handler_name)
+{
+	irq_domain_set_hwirq_and_chip(domain, virq, hwirq, chip, chip_data);
+	__irq_set_handler(virq, handler, 0, handler_name);
+	irq_set_handler_data(virq, handler_data);
+}
+EXPORT_SYMBOL(irq_domain_set_info);
+
+/**
+ * irq_domain_free_irqs_common - Clear irq_data and free the parent
+ * @domain:	Interrupt domain to match
+ * @virq:	IRQ number to start with
+ * @nr_irqs:	The number of irqs to free
+ */
+void irq_domain_free_irqs_common(struct irq_domain *domain, unsigned int virq,
+				 unsigned int nr_irqs)
+{
+	struct irq_data *irq_data;
+	int i;
+
+	for (i = 0; i < nr_irqs; i++) {
+		irq_data = irq_domain_get_irq_data(domain, virq + i);
+		if (irq_data)
+			irq_domain_reset_irq_data(irq_data);
+	}
+	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+}
+EXPORT_SYMBOL_GPL(irq_domain_free_irqs_common);
+
+/**
+ * irq_domain_free_irqs_top - Clear handler and handler data, clear irqdata and free parent
+ * @domain:	Interrupt domain to match
+ * @virq:	IRQ number to start with
+ * @nr_irqs:	The number of irqs to free
+ */
+void irq_domain_free_irqs_top(struct irq_domain *domain, unsigned int virq,
+			      unsigned int nr_irqs)
+{
+	int i;
+
+	for (i = 0; i < nr_irqs; i++) {
+		irq_set_handler_data(virq + i, NULL);
+		irq_set_handler(virq + i, NULL);
+	}
+	irq_domain_free_irqs_common(domain, virq, nr_irqs);
+}
+
+static void irq_domain_free_irqs_hierarchy(struct irq_domain *domain,
+					   unsigned int irq_base,
+					   unsigned int nr_irqs)
+{
+	unsigned int i;
+
+	if (!domain->ops->free)
+		return;
+
+	for (i = 0; i < nr_irqs; i++) {
+		if (irq_domain_get_irq_data(domain, irq_base + i))
+			domain->ops->free(domain, irq_base + i, 1);
+	}
+}
+
+int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain,
+				    unsigned int irq_base,
+				    unsigned int nr_irqs, void *arg)
+{
+	if (!domain->ops->alloc) {
+		pr_debug("domain->ops->alloc() is NULL\n");
+		return -ENOSYS;
+	}
+
+	return domain->ops->alloc(domain, irq_base, nr_irqs, arg);
+}
+
+static int irq_domain_alloc_irqs_locked(struct irq_domain *domain, int irq_base,
+					unsigned int nr_irqs, int node, void *arg,
+					bool realloc, const struct irq_affinity_desc *affinity)
+{
+	int i, ret, virq;
+
+	if (realloc && irq_base >= 0) {
+		virq = irq_base;
+	} else {
+		virq = irq_domain_alloc_descs(irq_base, nr_irqs, 0, node,
+					      affinity);
+		if (virq < 0) {
+			pr_debug("cannot allocate IRQ(base %d, count %d)\n",
+				 irq_base, nr_irqs);
+			return virq;
+		}
+	}
+
+	if (irq_domain_alloc_irq_data(domain, virq, nr_irqs)) {
+		pr_debug("cannot allocate memory for IRQ%d\n", virq);
+		ret = -ENOMEM;
+		goto out_free_desc;
+	}
+
+	ret = irq_domain_alloc_irqs_hierarchy(domain, virq, nr_irqs, arg);
+	if (ret < 0)
+		goto out_free_irq_data;
+
+	for (i = 0; i < nr_irqs; i++) {
+		ret = irq_domain_trim_hierarchy(virq + i);
+		if (ret)
+			goto out_free_irq_data;
+	}
+
+	for (i = 0; i < nr_irqs; i++)
+		irq_domain_insert_irq(virq + i);
+
+	return virq;
+
+out_free_irq_data:
+	irq_domain_free_irq_data(virq, nr_irqs);
+out_free_desc:
+	irq_free_descs(virq, nr_irqs);
+	return ret;
+}
+
+/**
+ * __irq_domain_alloc_irqs - Allocate IRQs from domain
+ * @domain:	domain to allocate from
+ * @irq_base:	allocate specified IRQ number if irq_base >= 0
+ * @nr_irqs:	number of IRQs to allocate
+ * @node:	NUMA node id for memory allocation
+ * @arg:	domain specific argument
+ * @realloc:	IRQ descriptors have already been allocated if true
+ * @affinity:	Optional irq affinity mask for multiqueue devices
+ *
+ * Allocate IRQ numbers and initialized all data structures to support
+ * hierarchy IRQ domains.
+ * Parameter @realloc is mainly to support legacy IRQs.
+ * Returns error code or allocated IRQ number
+ *
+ * The whole process to setup an IRQ has been split into two steps.
+ * The first step, __irq_domain_alloc_irqs(), is to allocate IRQ
+ * descriptor and required hardware resources. The second step,
+ * irq_domain_activate_irq(), is to program the hardware with preallocated
+ * resources. In this way, it's easier to rollback when failing to
+ * allocate resources.
+ */
+int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
+			    unsigned int nr_irqs, int node, void *arg,
+			    bool realloc, const struct irq_affinity_desc *affinity)
+{
+	int ret;
+
+	if (domain == NULL) {
+		domain = irq_default_domain;
+		if (WARN(!domain, "domain is NULL; cannot allocate IRQ\n"))
+			return -EINVAL;
+	}
+
+	mutex_lock(&irq_domain_mutex);
+	ret = irq_domain_alloc_irqs_locked(domain, irq_base, nr_irqs, node, arg,
+					   realloc, affinity);
+	mutex_unlock(&irq_domain_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__irq_domain_alloc_irqs);
+
+/* The irq_data was moved, fix the revmap to refer to the new location */
+static void irq_domain_fix_revmap(struct irq_data *d)
+{
+	void __rcu **slot;
+
+	if (irq_domain_is_nomap(d->domain))
+		return;
+
+	/* Fix up the revmap. */
+	mutex_lock(&d->domain->revmap_mutex);
+	if (d->hwirq < d->domain->revmap_size) {
+		/* Not using radix tree */
+		rcu_assign_pointer(d->domain->revmap[d->hwirq], d);
+	} else {
+		slot = radix_tree_lookup_slot(&d->domain->revmap_tree, d->hwirq);
+		if (slot)
+			radix_tree_replace_slot(&d->domain->revmap_tree, slot, d);
+	}
+	mutex_unlock(&d->domain->revmap_mutex);
+}
+
+/**
+ * irq_domain_push_irq() - Push a domain in to the top of a hierarchy.
+ * @domain:	Domain to push.
+ * @virq:	Irq to push the domain in to.
+ * @arg:	Passed to the irq_domain_ops alloc() function.
+ *
+ * For an already existing irqdomain hierarchy, as might be obtained
+ * via a call to pci_enable_msix(), add an additional domain to the
+ * head of the processing chain.  Must be called before request_irq()
+ * has been called.
+ */
+int irq_domain_push_irq(struct irq_domain *domain, int virq, void *arg)
+{
+	struct irq_data *child_irq_data;
+	struct irq_data *root_irq_data = irq_get_irq_data(virq);
+	struct irq_desc *desc;
+	int rv = 0;
+
+	/*
+	 * Check that no action has been set, which indicates the virq
+	 * is in a state where this function doesn't have to deal with
+	 * races between interrupt handling and maintaining the
+	 * hierarchy.  This will catch gross misuse.  Attempting to
+	 * make the check race free would require holding locks across
+	 * calls to struct irq_domain_ops->alloc(), which could lead
+	 * to deadlock, so we just do a simple check before starting.
+	 */
+	desc = irq_to_desc(virq);
+	if (!desc)
+		return -EINVAL;
+	if (WARN_ON(desc->action))
+		return -EBUSY;
+
+	if (domain == NULL)
+		return -EINVAL;
+
+	if (WARN_ON(!irq_domain_is_hierarchy(domain)))
+		return -EINVAL;
+
+	if (!root_irq_data)
+		return -EINVAL;
+
+	if (domain->parent != root_irq_data->domain)
+		return -EINVAL;
+
+	child_irq_data = kzalloc_node(sizeof(*child_irq_data), GFP_KERNEL,
+				      irq_data_get_node(root_irq_data));
+	if (!child_irq_data)
+		return -ENOMEM;
+
+	mutex_lock(&irq_domain_mutex);
+
+	/* Copy the original irq_data. */
+	*child_irq_data = *root_irq_data;
+
+	/*
+	 * Overwrite the root_irq_data, which is embedded in struct
+	 * irq_desc, with values for this domain.
+	 */
+	root_irq_data->parent_data = child_irq_data;
+	root_irq_data->domain = domain;
+	root_irq_data->mask = 0;
+	root_irq_data->hwirq = 0;
+	root_irq_data->chip = NULL;
+	root_irq_data->chip_data = NULL;
+
+	/* May (probably does) set hwirq, chip, etc. */
+	rv = irq_domain_alloc_irqs_hierarchy(domain, virq, 1, arg);
+	if (rv) {
+		/* Restore the original irq_data. */
+		*root_irq_data = *child_irq_data;
+		kfree(child_irq_data);
+		goto error;
+	}
+
+	irq_domain_fix_revmap(child_irq_data);
+	irq_domain_set_mapping(domain, root_irq_data->hwirq, root_irq_data);
+
+error:
+	mutex_unlock(&irq_domain_mutex);
+
+	return rv;
+}
+EXPORT_SYMBOL_GPL(irq_domain_push_irq);
+
+/**
+ * irq_domain_pop_irq() - Remove a domain from the top of a hierarchy.
+ * @domain:	Domain to remove.
+ * @virq:	Irq to remove the domain from.
+ *
+ * Undo the effects of a call to irq_domain_push_irq().  Must be
+ * called either before request_irq() or after free_irq().
+ */
+int irq_domain_pop_irq(struct irq_domain *domain, int virq)
+{
+	struct irq_data *root_irq_data = irq_get_irq_data(virq);
+	struct irq_data *child_irq_data;
+	struct irq_data *tmp_irq_data;
+	struct irq_desc *desc;
+
+	/*
+	 * Check that no action is set, which indicates the virq is in
+	 * a state where this function doesn't have to deal with races
+	 * between interrupt handling and maintaining the hierarchy.
+	 * This will catch gross misuse.  Attempting to make the check
+	 * race free would require holding locks across calls to
+	 * struct irq_domain_ops->free(), which could lead to
+	 * deadlock, so we just do a simple check before starting.
+	 */
+	desc = irq_to_desc(virq);
+	if (!desc)
+		return -EINVAL;
+	if (WARN_ON(desc->action))
+		return -EBUSY;
+
+	if (domain == NULL)
+		return -EINVAL;
+
+	if (!root_irq_data)
+		return -EINVAL;
+
+	tmp_irq_data = irq_domain_get_irq_data(domain, virq);
+
+	/* We can only "pop" if this domain is at the top of the list */
+	if (WARN_ON(root_irq_data != tmp_irq_data))
+		return -EINVAL;
+
+	if (WARN_ON(root_irq_data->domain != domain))
+		return -EINVAL;
+
+	child_irq_data = root_irq_data->parent_data;
+	if (WARN_ON(!child_irq_data))
+		return -EINVAL;
+
+	mutex_lock(&irq_domain_mutex);
+
+	root_irq_data->parent_data = NULL;
+
+	irq_domain_clear_mapping(domain, root_irq_data->hwirq);
+	irq_domain_free_irqs_hierarchy(domain, virq, 1);
+
+	/* Restore the original irq_data. */
+	*root_irq_data = *child_irq_data;
+
+	irq_domain_fix_revmap(root_irq_data);
+
+	mutex_unlock(&irq_domain_mutex);
+
+	kfree(child_irq_data);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_domain_pop_irq);
+
+/**
+ * irq_domain_free_irqs - Free IRQ number and associated data structures
+ * @virq:	base IRQ number
+ * @nr_irqs:	number of IRQs to free
+ */
+void irq_domain_free_irqs(unsigned int virq, unsigned int nr_irqs)
+{
+	struct irq_data *data = irq_get_irq_data(virq);
+	int i;
+
+	if (WARN(!data || !data->domain || !data->domain->ops->free,
+		 "NULL pointer, cannot free irq\n"))
+		return;
+
+	mutex_lock(&irq_domain_mutex);
+	for (i = 0; i < nr_irqs; i++)
+		irq_domain_remove_irq(virq + i);
+	irq_domain_free_irqs_hierarchy(data->domain, virq, nr_irqs);
+	mutex_unlock(&irq_domain_mutex);
+
+	irq_domain_free_irq_data(virq, nr_irqs);
+	irq_free_descs(virq, nr_irqs);
+}
+
+/**
+ * irq_domain_alloc_irqs_parent - Allocate interrupts from parent domain
+ * @domain:	Domain below which interrupts must be allocated
+ * @irq_base:	Base IRQ number
+ * @nr_irqs:	Number of IRQs to allocate
+ * @arg:	Allocation data (arch/domain specific)
+ */
+int irq_domain_alloc_irqs_parent(struct irq_domain *domain,
+				 unsigned int irq_base, unsigned int nr_irqs,
+				 void *arg)
+{
+	if (!domain->parent)
+		return -ENOSYS;
+
+	return irq_domain_alloc_irqs_hierarchy(domain->parent, irq_base,
+					       nr_irqs, arg);
+}
+EXPORT_SYMBOL_GPL(irq_domain_alloc_irqs_parent);
+
+/**
+ * irq_domain_free_irqs_parent - Free interrupts from parent domain
+ * @domain:	Domain below which interrupts must be freed
+ * @irq_base:	Base IRQ number
+ * @nr_irqs:	Number of IRQs to free
+ */
+void irq_domain_free_irqs_parent(struct irq_domain *domain,
+				 unsigned int irq_base, unsigned int nr_irqs)
+{
+	if (!domain->parent)
+		return;
+
+	irq_domain_free_irqs_hierarchy(domain->parent, irq_base, nr_irqs);
+}
+EXPORT_SYMBOL_GPL(irq_domain_free_irqs_parent);
+
+static void __irq_domain_deactivate_irq(struct irq_data *irq_data)
+{
+	if (irq_data && irq_data->domain) {
+		struct irq_domain *domain = irq_data->domain;
+
+		if (domain->ops->deactivate)
+			domain->ops->deactivate(domain, irq_data);
+		if (irq_data->parent_data)
+			__irq_domain_deactivate_irq(irq_data->parent_data);
+	}
+}
+
+static int __irq_domain_activate_irq(struct irq_data *irqd, bool reserve)
+{
+	int ret = 0;
+
+	if (irqd && irqd->domain) {
+		struct irq_domain *domain = irqd->domain;
+
+		if (irqd->parent_data)
+			ret = __irq_domain_activate_irq(irqd->parent_data,
+							reserve);
+		if (!ret && domain->ops->activate) {
+			ret = domain->ops->activate(domain, irqd, reserve);
+			/* Rollback in case of error */
+			if (ret && irqd->parent_data)
+				__irq_domain_deactivate_irq(irqd->parent_data);
+		}
+	}
+	return ret;
+}
+
+/**
+ * irq_domain_activate_irq - Call domain_ops->activate recursively to activate
+ *			     interrupt
+ * @irq_data:	Outermost irq_data associated with interrupt
+ * @reserve:	If set only reserve an interrupt vector instead of assigning one
+ *
+ * This is the second step to call domain_ops->activate to program interrupt
+ * controllers, so the interrupt could actually get delivered.
+ */
+int irq_domain_activate_irq(struct irq_data *irq_data, bool reserve)
+{
+	int ret = 0;
+
+	if (!irqd_is_activated(irq_data))
+		ret = __irq_domain_activate_irq(irq_data, reserve);
+	if (!ret)
+		irqd_set_activated(irq_data);
+	return ret;
+}
+
+/**
+ * irq_domain_deactivate_irq - Call domain_ops->deactivate recursively to
+ *			       deactivate interrupt
+ * @irq_data: outermost irq_data associated with interrupt
+ *
+ * It calls domain_ops->deactivate to program interrupt controllers to disable
+ * interrupt delivery.
+ */
+void irq_domain_deactivate_irq(struct irq_data *irq_data)
+{
+	if (irqd_is_activated(irq_data)) {
+		__irq_domain_deactivate_irq(irq_data);
+		irqd_clr_activated(irq_data);
+	}
+}
+
+static void irq_domain_check_hierarchy(struct irq_domain *domain)
+{
+	/* Hierarchy irq_domains must implement callback alloc() */
+	if (domain->ops->alloc)
+		domain->flags |= IRQ_DOMAIN_FLAG_HIERARCHY;
+}
+
+/**
+ * irq_domain_hierarchical_is_msi_remap - Check if the domain or any
+ * parent has MSI remapping support
+ * @domain: domain pointer
+ */
+bool irq_domain_hierarchical_is_msi_remap(struct irq_domain *domain)
+{
+	for (; domain; domain = domain->parent) {
+		if (irq_domain_is_msi_remap(domain))
+			return true;
+	}
+	return false;
+}
+#else	/* CONFIG_IRQ_DOMAIN_HIERARCHY */
+/**
+ * irq_domain_get_irq_data - Get irq_data associated with @virq and @domain
+ * @domain:	domain to match
+ * @virq:	IRQ number to get irq_data
+ */
+struct irq_data *irq_domain_get_irq_data(struct irq_domain *domain,
+					 unsigned int virq)
+{
+	struct irq_data *irq_data = irq_get_irq_data(virq);
+
+	return (irq_data && irq_data->domain == domain) ? irq_data : NULL;
+}
+EXPORT_SYMBOL_GPL(irq_domain_get_irq_data);
+
+/**
+ * irq_domain_set_info - Set the complete data for a @virq in @domain
+ * @domain:		Interrupt domain to match
+ * @virq:		IRQ number
+ * @hwirq:		The hardware interrupt number
+ * @chip:		The associated interrupt chip
+ * @chip_data:		The associated interrupt chip data
+ * @handler:		The interrupt flow handler
+ * @handler_data:	The interrupt flow handler data
+ * @handler_name:	The interrupt handler name
+ */
+void irq_domain_set_info(struct irq_domain *domain, unsigned int virq,
+			 irq_hw_number_t hwirq, const struct irq_chip *chip,
+			 void *chip_data, irq_flow_handler_t handler,
+			 void *handler_data, const char *handler_name)
+{
+	irq_set_chip_and_handler_name(virq, chip, handler, handler_name);
+	irq_set_chip_data(virq, chip_data);
+	irq_set_handler_data(virq, handler_data);
+}
+
+static int irq_domain_alloc_irqs_locked(struct irq_domain *domain, int irq_base,
+					unsigned int nr_irqs, int node, void *arg,
+					bool realloc, const struct irq_affinity_desc *affinity)
+{
+	return -EINVAL;
+}
+
+static void irq_domain_check_hierarchy(struct irq_domain *domain)
+{
+}
+#endif	/* CONFIG_IRQ_DOMAIN_HIERARCHY */
+
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+static struct dentry *domain_dir;
+
+static void
+irq_domain_debug_show_one(struct seq_file *m, struct irq_domain *d, int ind)
+{
+	seq_printf(m, "%*sname:   %s\n", ind, "", d->name);
+	seq_printf(m, "%*ssize:   %u\n", ind + 1, "", d->revmap_size);
+	seq_printf(m, "%*smapped: %u\n", ind + 1, "", d->mapcount);
+	seq_printf(m, "%*sflags:  0x%08x\n", ind +1 , "", d->flags);
+	if (d->ops && d->ops->debug_show)
+		d->ops->debug_show(m, d, NULL, ind + 1);
+#ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+	if (!d->parent)
+		return;
+	seq_printf(m, "%*sparent: %s\n", ind + 1, "", d->parent->name);
+	irq_domain_debug_show_one(m, d->parent, ind + 4);
+#endif
+}
+
+static int irq_domain_debug_show(struct seq_file *m, void *p)
+{
+	struct irq_domain *d = m->private;
+
+	/* Default domain? Might be NULL */
+	if (!d) {
+		if (!irq_default_domain)
+			return 0;
+		d = irq_default_domain;
+	}
+	irq_domain_debug_show_one(m, d, 0);
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(irq_domain_debug);
+
+static void debugfs_add_domain_dir(struct irq_domain *d)
+{
+	if (!d->name || !domain_dir)
+		return;
+	debugfs_create_file(d->name, 0444, domain_dir, d,
+			    &irq_domain_debug_fops);
+}
+
+static void debugfs_remove_domain_dir(struct irq_domain *d)
+{
+	debugfs_lookup_and_remove(d->name, domain_dir);
+}
+
+void __init irq_domain_debugfs_init(struct dentry *root)
+{
+	struct irq_domain *d;
+
+	domain_dir = debugfs_create_dir("domains", root);
+
+	debugfs_create_file("default", 0444, domain_dir, NULL,
+			    &irq_domain_debug_fops);
+	mutex_lock(&irq_domain_mutex);
+	list_for_each_entry(d, &irq_domain_list, link)
+		debugfs_add_domain_dir(d);
+	mutex_unlock(&irq_domain_mutex);
+}
+#endif
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
new file mode 100644
index 000000000..40fe7806c
--- /dev/null
+++ b/kernel/irq/manage.c
@@ -0,0 +1,2934 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
+ * Copyright (C) 2005-2006 Thomas Gleixner
+ *
+ * This file contains driver APIs to the irq subsystem.
+ */
+
+#define pr_fmt(fmt) "genirq: " fmt
+
+#include <linux/irq.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/sched/rt.h>
+#include <linux/sched/task.h>
+#include <linux/sched/isolation.h>
+#include <uapi/linux/sched/types.h>
+#include <linux/task_work.h>
+
+#include "internals.h"
+
+#if defined(CONFIG_IRQ_FORCED_THREADING) && !defined(CONFIG_PREEMPT_RT)
+DEFINE_STATIC_KEY_FALSE(force_irqthreads_key);
+
+static int __init setup_forced_irqthreads(char *arg)
+{
+	static_branch_enable(&force_irqthreads_key);
+	return 0;
+}
+early_param("threadirqs", setup_forced_irqthreads);
+#endif
+
+static void __synchronize_hardirq(struct irq_desc *desc, bool sync_chip)
+{
+	struct irq_data *irqd = irq_desc_get_irq_data(desc);
+	bool inprogress;
+
+	do {
+		unsigned long flags;
+
+		/*
+		 * Wait until we're out of the critical section.  This might
+		 * give the wrong answer due to the lack of memory barriers.
+		 */
+		while (irqd_irq_inprogress(&desc->irq_data))
+			cpu_relax();
+
+		/* Ok, that indicated we're done: double-check carefully. */
+		raw_spin_lock_irqsave(&desc->lock, flags);
+		inprogress = irqd_irq_inprogress(&desc->irq_data);
+
+		/*
+		 * If requested and supported, check at the chip whether it
+		 * is in flight at the hardware level, i.e. already pending
+		 * in a CPU and waiting for service and acknowledge.
+		 */
+		if (!inprogress && sync_chip) {
+			/*
+			 * Ignore the return code. inprogress is only updated
+			 * when the chip supports it.
+			 */
+			__irq_get_irqchip_state(irqd, IRQCHIP_STATE_ACTIVE,
+						&inprogress);
+		}
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+		/* Oops, that failed? */
+	} while (inprogress);
+}
+
+/**
+ *	synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
+ *	@irq: interrupt number to wait for
+ *
+ *	This function waits for any pending hard IRQ handlers for this
+ *	interrupt to complete before returning. If you use this
+ *	function while holding a resource the IRQ handler may need you
+ *	will deadlock. It does not take associated threaded handlers
+ *	into account.
+ *
+ *	Do not use this for shutdown scenarios where you must be sure
+ *	that all parts (hardirq and threaded handler) have completed.
+ *
+ *	Returns: false if a threaded handler is active.
+ *
+ *	This function may be called - with care - from IRQ context.
+ *
+ *	It does not check whether there is an interrupt in flight at the
+ *	hardware level, but not serviced yet, as this might deadlock when
+ *	called with interrupts disabled and the target CPU of the interrupt
+ *	is the current CPU.
+ */
+bool synchronize_hardirq(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	if (desc) {
+		__synchronize_hardirq(desc, false);
+		return !atomic_read(&desc->threads_active);
+	}
+
+	return true;
+}
+EXPORT_SYMBOL(synchronize_hardirq);
+
+/**
+ *	synchronize_irq - wait for pending IRQ handlers (on other CPUs)
+ *	@irq: interrupt number to wait for
+ *
+ *	This function waits for any pending IRQ handlers for this interrupt
+ *	to complete before returning. If you use this function while
+ *	holding a resource the IRQ handler may need you will deadlock.
+ *
+ *	Can only be called from preemptible code as it might sleep when
+ *	an interrupt thread is associated to @irq.
+ *
+ *	It optionally makes sure (when the irq chip supports that method)
+ *	that the interrupt is not pending in any CPU and waiting for
+ *	service.
+ */
+void synchronize_irq(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	if (desc) {
+		__synchronize_hardirq(desc, true);
+		/*
+		 * We made sure that no hardirq handler is
+		 * running. Now verify that no threaded handlers are
+		 * active.
+		 */
+		wait_event(desc->wait_for_threads,
+			   !atomic_read(&desc->threads_active));
+	}
+}
+EXPORT_SYMBOL(synchronize_irq);
+
+#ifdef CONFIG_SMP
+cpumask_var_t irq_default_affinity;
+
+static bool __irq_can_set_affinity(struct irq_desc *desc)
+{
+	if (!desc || !irqd_can_balance(&desc->irq_data) ||
+	    !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
+		return false;
+	return true;
+}
+
+/**
+ *	irq_can_set_affinity - Check if the affinity of a given irq can be set
+ *	@irq:		Interrupt to check
+ *
+ */
+int irq_can_set_affinity(unsigned int irq)
+{
+	return __irq_can_set_affinity(irq_to_desc(irq));
+}
+
+/**
+ * irq_can_set_affinity_usr - Check if affinity of a irq can be set from user space
+ * @irq:	Interrupt to check
+ *
+ * Like irq_can_set_affinity() above, but additionally checks for the
+ * AFFINITY_MANAGED flag.
+ */
+bool irq_can_set_affinity_usr(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	return __irq_can_set_affinity(desc) &&
+		!irqd_affinity_is_managed(&desc->irq_data);
+}
+
+/**
+ *	irq_set_thread_affinity - Notify irq threads to adjust affinity
+ *	@desc:		irq descriptor which has affinity changed
+ *
+ *	We just set IRQTF_AFFINITY and delegate the affinity setting
+ *	to the interrupt thread itself. We can not call
+ *	set_cpus_allowed_ptr() here as we hold desc->lock and this
+ *	code can be called from hard interrupt context.
+ */
+void irq_set_thread_affinity(struct irq_desc *desc)
+{
+	struct irqaction *action;
+
+	for_each_action_of_desc(desc, action)
+		if (action->thread)
+			set_bit(IRQTF_AFFINITY, &action->thread_flags);
+}
+
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+static void irq_validate_effective_affinity(struct irq_data *data)
+{
+	const struct cpumask *m = irq_data_get_effective_affinity_mask(data);
+	struct irq_chip *chip = irq_data_get_irq_chip(data);
+
+	if (!cpumask_empty(m))
+		return;
+	pr_warn_once("irq_chip %s did not update eff. affinity mask of irq %u\n",
+		     chip->name, data->irq);
+}
+#else
+static inline void irq_validate_effective_affinity(struct irq_data *data) { }
+#endif
+
+int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
+			bool force)
+{
+	struct irq_desc *desc = irq_data_to_desc(data);
+	struct irq_chip *chip = irq_data_get_irq_chip(data);
+	const struct cpumask  *prog_mask;
+	int ret;
+
+	static DEFINE_RAW_SPINLOCK(tmp_mask_lock);
+	static struct cpumask tmp_mask;
+
+	if (!chip || !chip->irq_set_affinity)
+		return -EINVAL;
+
+	raw_spin_lock(&tmp_mask_lock);
+	/*
+	 * If this is a managed interrupt and housekeeping is enabled on
+	 * it check whether the requested affinity mask intersects with
+	 * a housekeeping CPU. If so, then remove the isolated CPUs from
+	 * the mask and just keep the housekeeping CPU(s). This prevents
+	 * the affinity setter from routing the interrupt to an isolated
+	 * CPU to avoid that I/O submitted from a housekeeping CPU causes
+	 * interrupts on an isolated one.
+	 *
+	 * If the masks do not intersect or include online CPU(s) then
+	 * keep the requested mask. The isolated target CPUs are only
+	 * receiving interrupts when the I/O operation was submitted
+	 * directly from them.
+	 *
+	 * If all housekeeping CPUs in the affinity mask are offline, the
+	 * interrupt will be migrated by the CPU hotplug code once a
+	 * housekeeping CPU which belongs to the affinity mask comes
+	 * online.
+	 */
+	if (irqd_affinity_is_managed(data) &&
+	    housekeeping_enabled(HK_TYPE_MANAGED_IRQ)) {
+		const struct cpumask *hk_mask;
+
+		hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);
+
+		cpumask_and(&tmp_mask, mask, hk_mask);
+		if (!cpumask_intersects(&tmp_mask, cpu_online_mask))
+			prog_mask = mask;
+		else
+			prog_mask = &tmp_mask;
+	} else {
+		prog_mask = mask;
+	}
+
+	/*
+	 * Make sure we only provide online CPUs to the irqchip,
+	 * unless we are being asked to force the affinity (in which
+	 * case we do as we are told).
+	 */
+	cpumask_and(&tmp_mask, prog_mask, cpu_online_mask);
+	if (!force && !cpumask_empty(&tmp_mask))
+		ret = chip->irq_set_affinity(data, &tmp_mask, force);
+	else if (force)
+		ret = chip->irq_set_affinity(data, mask, force);
+	else
+		ret = -EINVAL;
+
+	raw_spin_unlock(&tmp_mask_lock);
+
+	switch (ret) {
+	case IRQ_SET_MASK_OK:
+	case IRQ_SET_MASK_OK_DONE:
+		cpumask_copy(desc->irq_common_data.affinity, mask);
+		fallthrough;
+	case IRQ_SET_MASK_OK_NOCOPY:
+		irq_validate_effective_affinity(data);
+		irq_set_thread_affinity(desc);
+		ret = 0;
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+static inline int irq_set_affinity_pending(struct irq_data *data,
+					   const struct cpumask *dest)
+{
+	struct irq_desc *desc = irq_data_to_desc(data);
+
+	irqd_set_move_pending(data);
+	irq_copy_pending(desc, dest);
+	return 0;
+}
+#else
+static inline int irq_set_affinity_pending(struct irq_data *data,
+					   const struct cpumask *dest)
+{
+	return -EBUSY;
+}
+#endif
+
+static int irq_try_set_affinity(struct irq_data *data,
+				const struct cpumask *dest, bool force)
+{
+	int ret = irq_do_set_affinity(data, dest, force);
+
+	/*
+	 * In case that the underlying vector management is busy and the
+	 * architecture supports the generic pending mechanism then utilize
+	 * this to avoid returning an error to user space.
+	 */
+	if (ret == -EBUSY && !force)
+		ret = irq_set_affinity_pending(data, dest);
+	return ret;
+}
+
+static bool irq_set_affinity_deactivated(struct irq_data *data,
+					 const struct cpumask *mask, bool force)
+{
+	struct irq_desc *desc = irq_data_to_desc(data);
+
+	/*
+	 * Handle irq chips which can handle affinity only in activated
+	 * state correctly
+	 *
+	 * If the interrupt is not yet activated, just store the affinity
+	 * mask and do not call the chip driver at all. On activation the
+	 * driver has to make sure anyway that the interrupt is in a
+	 * usable state so startup works.
+	 */
+	if (!IS_ENABLED(CONFIG_IRQ_DOMAIN_HIERARCHY) ||
+	    irqd_is_activated(data) || !irqd_affinity_on_activate(data))
+		return false;
+
+	cpumask_copy(desc->irq_common_data.affinity, mask);
+	irq_data_update_effective_affinity(data, mask);
+	irqd_set(data, IRQD_AFFINITY_SET);
+	return true;
+}
+
+int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
+			    bool force)
+{
+	struct irq_chip *chip = irq_data_get_irq_chip(data);
+	struct irq_desc *desc = irq_data_to_desc(data);
+	int ret = 0;
+
+	if (!chip || !chip->irq_set_affinity)
+		return -EINVAL;
+
+	if (irq_set_affinity_deactivated(data, mask, force))
+		return 0;
+
+	if (irq_can_move_pcntxt(data) && !irqd_is_setaffinity_pending(data)) {
+		ret = irq_try_set_affinity(data, mask, force);
+	} else {
+		irqd_set_move_pending(data);
+		irq_copy_pending(desc, mask);
+	}
+
+	if (desc->affinity_notify) {
+		kref_get(&desc->affinity_notify->kref);
+		if (!schedule_work(&desc->affinity_notify->work)) {
+			/* Work was already scheduled, drop our extra ref */
+			kref_put(&desc->affinity_notify->kref,
+				 desc->affinity_notify->release);
+		}
+	}
+	irqd_set(data, IRQD_AFFINITY_SET);
+
+	return ret;
+}
+
+/**
+ * irq_update_affinity_desc - Update affinity management for an interrupt
+ * @irq:	The interrupt number to update
+ * @affinity:	Pointer to the affinity descriptor
+ *
+ * This interface can be used to configure the affinity management of
+ * interrupts which have been allocated already.
+ *
+ * There are certain limitations on when it may be used - attempts to use it
+ * for when the kernel is configured for generic IRQ reservation mode (in
+ * config GENERIC_IRQ_RESERVATION_MODE) will fail, as it may conflict with
+ * managed/non-managed interrupt accounting. In addition, attempts to use it on
+ * an interrupt which is already started or which has already been configured
+ * as managed will also fail, as these mean invalid init state or double init.
+ */
+int irq_update_affinity_desc(unsigned int irq,
+			     struct irq_affinity_desc *affinity)
+{
+	struct irq_desc *desc;
+	unsigned long flags;
+	bool activated;
+	int ret = 0;
+
+	/*
+	 * Supporting this with the reservation scheme used by x86 needs
+	 * some more thought. Fail it for now.
+	 */
+	if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))
+		return -EOPNOTSUPP;
+
+	desc = irq_get_desc_buslock(irq, &flags, 0);
+	if (!desc)
+		return -EINVAL;
+
+	/* Requires the interrupt to be shut down */
+	if (irqd_is_started(&desc->irq_data)) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+
+	/* Interrupts which are already managed cannot be modified */
+	if (irqd_affinity_is_managed(&desc->irq_data)) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+
+	/*
+	 * Deactivate the interrupt. That's required to undo
+	 * anything an earlier activation has established.
+	 */
+	activated = irqd_is_activated(&desc->irq_data);
+	if (activated)
+		irq_domain_deactivate_irq(&desc->irq_data);
+
+	if (affinity->is_managed) {
+		irqd_set(&desc->irq_data, IRQD_AFFINITY_MANAGED);
+		irqd_set(&desc->irq_data, IRQD_MANAGED_SHUTDOWN);
+	}
+
+	cpumask_copy(desc->irq_common_data.affinity, &affinity->mask);
+
+	/* Restore the activation state */
+	if (activated)
+		irq_domain_activate_irq(&desc->irq_data, false);
+
+out_unlock:
+	irq_put_desc_busunlock(desc, flags);
+	return ret;
+}
+
+static int __irq_set_affinity(unsigned int irq, const struct cpumask *mask,
+			      bool force)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	unsigned long flags;
+	int ret;
+
+	if (!desc)
+		return -EINVAL;
+
+	raw_spin_lock_irqsave(&desc->lock, flags);
+	ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+	return ret;
+}
+
+/**
+ * irq_set_affinity - Set the irq affinity of a given irq
+ * @irq:	Interrupt to set affinity
+ * @cpumask:	cpumask
+ *
+ * Fails if cpumask does not contain an online CPU
+ */
+int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
+{
+	return __irq_set_affinity(irq, cpumask, false);
+}
+EXPORT_SYMBOL_GPL(irq_set_affinity);
+
+/**
+ * irq_force_affinity - Force the irq affinity of a given irq
+ * @irq:	Interrupt to set affinity
+ * @cpumask:	cpumask
+ *
+ * Same as irq_set_affinity, but without checking the mask against
+ * online cpus.
+ *
+ * Solely for low level cpu hotplug code, where we need to make per
+ * cpu interrupts affine before the cpu becomes online.
+ */
+int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
+{
+	return __irq_set_affinity(irq, cpumask, true);
+}
+EXPORT_SYMBOL_GPL(irq_force_affinity);
+
+int __irq_apply_affinity_hint(unsigned int irq, const struct cpumask *m,
+			      bool setaffinity)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
+
+	if (!desc)
+		return -EINVAL;
+	desc->affinity_hint = m;
+	irq_put_desc_unlock(desc, flags);
+	if (m && setaffinity)
+		__irq_set_affinity(irq, m, false);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__irq_apply_affinity_hint);
+
+static void irq_affinity_notify(struct work_struct *work)
+{
+	struct irq_affinity_notify *notify =
+		container_of(work, struct irq_affinity_notify, work);
+	struct irq_desc *desc = irq_to_desc(notify->irq);
+	cpumask_var_t cpumask;
+	unsigned long flags;
+
+	if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
+		goto out;
+
+	raw_spin_lock_irqsave(&desc->lock, flags);
+	if (irq_move_pending(&desc->irq_data))
+		irq_get_pending(cpumask, desc);
+	else
+		cpumask_copy(cpumask, desc->irq_common_data.affinity);
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+	notify->notify(notify, cpumask);
+
+	free_cpumask_var(cpumask);
+out:
+	kref_put(&notify->kref, notify->release);
+}
+
+/**
+ *	irq_set_affinity_notifier - control notification of IRQ affinity changes
+ *	@irq:		Interrupt for which to enable/disable notification
+ *	@notify:	Context for notification, or %NULL to disable
+ *			notification.  Function pointers must be initialised;
+ *			the other fields will be initialised by this function.
+ *
+ *	Must be called in process context.  Notification may only be enabled
+ *	after the IRQ is allocated and must be disabled before the IRQ is
+ *	freed using free_irq().
+ */
+int
+irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	struct irq_affinity_notify *old_notify;
+	unsigned long flags;
+
+	/* The release function is promised process context */
+	might_sleep();
+
+	if (!desc || desc->istate & IRQS_NMI)
+		return -EINVAL;
+
+	/* Complete initialisation of *notify */
+	if (notify) {
+		notify->irq = irq;
+		kref_init(&notify->kref);
+		INIT_WORK(&notify->work, irq_affinity_notify);
+	}
+
+	raw_spin_lock_irqsave(&desc->lock, flags);
+	old_notify = desc->affinity_notify;
+	desc->affinity_notify = notify;
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+	if (old_notify) {
+		if (cancel_work_sync(&old_notify->work)) {
+			/* Pending work had a ref, put that one too */
+			kref_put(&old_notify->kref, old_notify->release);
+		}
+		kref_put(&old_notify->kref, old_notify->release);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
+
+#ifndef CONFIG_AUTO_IRQ_AFFINITY
+/*
+ * Generic version of the affinity autoselector.
+ */
+int irq_setup_affinity(struct irq_desc *desc)
+{
+	struct cpumask *set = irq_default_affinity;
+	int ret, node = irq_desc_get_node(desc);
+	static DEFINE_RAW_SPINLOCK(mask_lock);
+	static struct cpumask mask;
+
+	/* Excludes PER_CPU and NO_BALANCE interrupts */
+	if (!__irq_can_set_affinity(desc))
+		return 0;
+
+	raw_spin_lock(&mask_lock);
+	/*
+	 * Preserve the managed affinity setting and a userspace affinity
+	 * setup, but make sure that one of the targets is online.
+	 */
+	if (irqd_affinity_is_managed(&desc->irq_data) ||
+	    irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
+		if (cpumask_intersects(desc->irq_common_data.affinity,
+				       cpu_online_mask))
+			set = desc->irq_common_data.affinity;
+		else
+			irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
+	}
+
+	cpumask_and(&mask, cpu_online_mask, set);
+	if (cpumask_empty(&mask))
+		cpumask_copy(&mask, cpu_online_mask);
+
+	if (node != NUMA_NO_NODE) {
+		const struct cpumask *nodemask = cpumask_of_node(node);
+
+		/* make sure at least one of the cpus in nodemask is online */
+		if (cpumask_intersects(&mask, nodemask))
+			cpumask_and(&mask, &mask, nodemask);
+	}
+	ret = irq_do_set_affinity(&desc->irq_data, &mask, false);
+	raw_spin_unlock(&mask_lock);
+	return ret;
+}
+#else
+/* Wrapper for ALPHA specific affinity selector magic */
+int irq_setup_affinity(struct irq_desc *desc)
+{
+	return irq_select_affinity(irq_desc_get_irq(desc));
+}
+#endif /* CONFIG_AUTO_IRQ_AFFINITY */
+#endif /* CONFIG_SMP */
+
+
+/**
+ *	irq_set_vcpu_affinity - Set vcpu affinity for the interrupt
+ *	@irq: interrupt number to set affinity
+ *	@vcpu_info: vCPU specific data or pointer to a percpu array of vCPU
+ *	            specific data for percpu_devid interrupts
+ *
+ *	This function uses the vCPU specific data to set the vCPU
+ *	affinity for an irq. The vCPU specific data is passed from
+ *	outside, such as KVM. One example code path is as below:
+ *	KVM -> IOMMU -> irq_set_vcpu_affinity().
+ */
+int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+	struct irq_data *data;
+	struct irq_chip *chip;
+	int ret = -ENOSYS;
+
+	if (!desc)
+		return -EINVAL;
+
+	data = irq_desc_get_irq_data(desc);
+	do {
+		chip = irq_data_get_irq_chip(data);
+		if (chip && chip->irq_set_vcpu_affinity)
+			break;
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+		data = data->parent_data;
+#else
+		data = NULL;
+#endif
+	} while (data);
+
+	if (data)
+		ret = chip->irq_set_vcpu_affinity(data, vcpu_info);
+	irq_put_desc_unlock(desc, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(irq_set_vcpu_affinity);
+
+void __disable_irq(struct irq_desc *desc)
+{
+	if (!desc->depth++)
+		irq_disable(desc);
+}
+
+static int __disable_irq_nosync(unsigned int irq)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
+
+	if (!desc)
+		return -EINVAL;
+	__disable_irq(desc);
+	irq_put_desc_busunlock(desc, flags);
+	return 0;
+}
+
+/**
+ *	disable_irq_nosync - disable an irq without waiting
+ *	@irq: Interrupt to disable
+ *
+ *	Disable the selected interrupt line.  Disables and Enables are
+ *	nested.
+ *	Unlike disable_irq(), this function does not ensure existing
+ *	instances of the IRQ handler have completed before returning.
+ *
+ *	This function may be called from IRQ context.
+ */
+void disable_irq_nosync(unsigned int irq)
+{
+	__disable_irq_nosync(irq);
+}
+EXPORT_SYMBOL(disable_irq_nosync);
+
+/**
+ *	disable_irq - disable an irq and wait for completion
+ *	@irq: Interrupt to disable
+ *
+ *	Disable the selected interrupt line.  Enables and Disables are
+ *	nested.
+ *	This function waits for any pending IRQ handlers for this interrupt
+ *	to complete before returning. If you use this function while
+ *	holding a resource the IRQ handler may need you will deadlock.
+ *
+ *	This function may be called - with care - from IRQ context.
+ */
+void disable_irq(unsigned int irq)
+{
+	if (!__disable_irq_nosync(irq))
+		synchronize_irq(irq);
+}
+EXPORT_SYMBOL(disable_irq);
+
+/**
+ *	disable_hardirq - disables an irq and waits for hardirq completion
+ *	@irq: Interrupt to disable
+ *
+ *	Disable the selected interrupt line.  Enables and Disables are
+ *	nested.
+ *	This function waits for any pending hard IRQ handlers for this
+ *	interrupt to complete before returning. If you use this function while
+ *	holding a resource the hard IRQ handler may need you will deadlock.
+ *
+ *	When used to optimistically disable an interrupt from atomic context
+ *	the return value must be checked.
+ *
+ *	Returns: false if a threaded handler is active.
+ *
+ *	This function may be called - with care - from IRQ context.
+ */
+bool disable_hardirq(unsigned int irq)
+{
+	if (!__disable_irq_nosync(irq))
+		return synchronize_hardirq(irq);
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(disable_hardirq);
+
+/**
+ *	disable_nmi_nosync - disable an nmi without waiting
+ *	@irq: Interrupt to disable
+ *
+ *	Disable the selected interrupt line. Disables and enables are
+ *	nested.
+ *	The interrupt to disable must have been requested through request_nmi.
+ *	Unlike disable_nmi(), this function does not ensure existing
+ *	instances of the IRQ handler have completed before returning.
+ */
+void disable_nmi_nosync(unsigned int irq)
+{
+	disable_irq_nosync(irq);
+}
+
+void __enable_irq(struct irq_desc *desc)
+{
+	switch (desc->depth) {
+	case 0:
+ err_out:
+		WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n",
+		     irq_desc_get_irq(desc));
+		break;
+	case 1: {
+		if (desc->istate & IRQS_SUSPENDED)
+			goto err_out;
+		/* Prevent probing on this irq: */
+		irq_settings_set_noprobe(desc);
+		/*
+		 * Call irq_startup() not irq_enable() here because the
+		 * interrupt might be marked NOAUTOEN. So irq_startup()
+		 * needs to be invoked when it gets enabled the first
+		 * time. If it was already started up, then irq_startup()
+		 * will invoke irq_enable() under the hood.
+		 */
+		irq_startup(desc, IRQ_RESEND, IRQ_START_FORCE);
+		break;
+	}
+	default:
+		desc->depth--;
+	}
+}
+
+/**
+ *	enable_irq - enable handling of an irq
+ *	@irq: Interrupt to enable
+ *
+ *	Undoes the effect of one call to disable_irq().  If this
+ *	matches the last disable, processing of interrupts on this
+ *	IRQ line is re-enabled.
+ *
+ *	This function may be called from IRQ context only when
+ *	desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
+ */
+void enable_irq(unsigned int irq)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
+
+	if (!desc)
+		return;
+	if (WARN(!desc->irq_data.chip,
+		 KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
+		goto out;
+
+	__enable_irq(desc);
+out:
+	irq_put_desc_busunlock(desc, flags);
+}
+EXPORT_SYMBOL(enable_irq);
+
+/**
+ *	enable_nmi - enable handling of an nmi
+ *	@irq: Interrupt to enable
+ *
+ *	The interrupt to enable must have been requested through request_nmi.
+ *	Undoes the effect of one call to disable_nmi(). If this
+ *	matches the last disable, processing of interrupts on this
+ *	IRQ line is re-enabled.
+ */
+void enable_nmi(unsigned int irq)
+{
+	enable_irq(irq);
+}
+
+static int set_irq_wake_real(unsigned int irq, unsigned int on)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	int ret = -ENXIO;
+
+	if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
+		return 0;
+
+	if (desc->irq_data.chip->irq_set_wake)
+		ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
+
+	return ret;
+}
+
+/**
+ *	irq_set_irq_wake - control irq power management wakeup
+ *	@irq:	interrupt to control
+ *	@on:	enable/disable power management wakeup
+ *
+ *	Enable/disable power management wakeup mode, which is
+ *	disabled by default.  Enables and disables must match,
+ *	just as they match for non-wakeup mode support.
+ *
+ *	Wakeup mode lets this IRQ wake the system from sleep
+ *	states like "suspend to RAM".
+ *
+ *	Note: irq enable/disable state is completely orthogonal
+ *	to the enable/disable state of irq wake. An irq can be
+ *	disabled with disable_irq() and still wake the system as
+ *	long as the irq has wake enabled. If this does not hold,
+ *	then the underlying irq chip and the related driver need
+ *	to be investigated.
+ */
+int irq_set_irq_wake(unsigned int irq, unsigned int on)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
+	int ret = 0;
+
+	if (!desc)
+		return -EINVAL;
+
+	/* Don't use NMIs as wake up interrupts please */
+	if (desc->istate & IRQS_NMI) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	/* wakeup-capable irqs can be shared between drivers that
+	 * don't need to have the same sleep mode behaviors.
+	 */
+	if (on) {
+		if (desc->wake_depth++ == 0) {
+			ret = set_irq_wake_real(irq, on);
+			if (ret)
+				desc->wake_depth = 0;
+			else
+				irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
+		}
+	} else {
+		if (desc->wake_depth == 0) {
+			WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
+		} else if (--desc->wake_depth == 0) {
+			ret = set_irq_wake_real(irq, on);
+			if (ret)
+				desc->wake_depth = 1;
+			else
+				irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
+		}
+	}
+
+out_unlock:
+	irq_put_desc_busunlock(desc, flags);
+	return ret;
+}
+EXPORT_SYMBOL(irq_set_irq_wake);
+
+/*
+ * Internal function that tells the architecture code whether a
+ * particular irq has been exclusively allocated or is available
+ * for driver use.
+ */
+int can_request_irq(unsigned int irq, unsigned long irqflags)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+	int canrequest = 0;
+
+	if (!desc)
+		return 0;
+
+	if (irq_settings_can_request(desc)) {
+		if (!desc->action ||
+		    irqflags & desc->action->flags & IRQF_SHARED)
+			canrequest = 1;
+	}
+	irq_put_desc_unlock(desc, flags);
+	return canrequest;
+}
+
+int __irq_set_trigger(struct irq_desc *desc, unsigned long flags)
+{
+	struct irq_chip *chip = desc->irq_data.chip;
+	int ret, unmask = 0;
+
+	if (!chip || !chip->irq_set_type) {
+		/*
+		 * IRQF_TRIGGER_* but the PIC does not support multiple
+		 * flow-types?
+		 */
+		pr_debug("No set_type function for IRQ %d (%s)\n",
+			 irq_desc_get_irq(desc),
+			 chip ? (chip->name ? : "unknown") : "unknown");
+		return 0;
+	}
+
+	if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
+		if (!irqd_irq_masked(&desc->irq_data))
+			mask_irq(desc);
+		if (!irqd_irq_disabled(&desc->irq_data))
+			unmask = 1;
+	}
+
+	/* Mask all flags except trigger mode */
+	flags &= IRQ_TYPE_SENSE_MASK;
+	ret = chip->irq_set_type(&desc->irq_data, flags);
+
+	switch (ret) {
+	case IRQ_SET_MASK_OK:
+	case IRQ_SET_MASK_OK_DONE:
+		irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
+		irqd_set(&desc->irq_data, flags);
+		fallthrough;
+
+	case IRQ_SET_MASK_OK_NOCOPY:
+		flags = irqd_get_trigger_type(&desc->irq_data);
+		irq_settings_set_trigger_mask(desc, flags);
+		irqd_clear(&desc->irq_data, IRQD_LEVEL);
+		irq_settings_clr_level(desc);
+		if (flags & IRQ_TYPE_LEVEL_MASK) {
+			irq_settings_set_level(desc);
+			irqd_set(&desc->irq_data, IRQD_LEVEL);
+		}
+
+		ret = 0;
+		break;
+	default:
+		pr_err("Setting trigger mode %lu for irq %u failed (%pS)\n",
+		       flags, irq_desc_get_irq(desc), chip->irq_set_type);
+	}
+	if (unmask)
+		unmask_irq(desc);
+	return ret;
+}
+
+#ifdef CONFIG_HARDIRQS_SW_RESEND
+int irq_set_parent(int irq, int parent_irq)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+
+	if (!desc)
+		return -EINVAL;
+
+	desc->parent_irq = parent_irq;
+
+	irq_put_desc_unlock(desc, flags);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_set_parent);
+#endif
+
+/*
+ * Default primary interrupt handler for threaded interrupts. Is
+ * assigned as primary handler when request_threaded_irq is called
+ * with handler == NULL. Useful for oneshot interrupts.
+ */
+static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
+{
+	return IRQ_WAKE_THREAD;
+}
+
+/*
+ * Primary handler for nested threaded interrupts. Should never be
+ * called.
+ */
+static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
+{
+	WARN(1, "Primary handler called for nested irq %d\n", irq);
+	return IRQ_NONE;
+}
+
+static irqreturn_t irq_forced_secondary_handler(int irq, void *dev_id)
+{
+	WARN(1, "Secondary action handler called for irq %d\n", irq);
+	return IRQ_NONE;
+}
+
+static int irq_wait_for_interrupt(struct irqaction *action)
+{
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		if (kthread_should_stop()) {
+			/* may need to run one last time */
+			if (test_and_clear_bit(IRQTF_RUNTHREAD,
+					       &action->thread_flags)) {
+				__set_current_state(TASK_RUNNING);
+				return 0;
+			}
+			__set_current_state(TASK_RUNNING);
+			return -1;
+		}
+
+		if (test_and_clear_bit(IRQTF_RUNTHREAD,
+				       &action->thread_flags)) {
+			__set_current_state(TASK_RUNNING);
+			return 0;
+		}
+		schedule();
+	}
+}
+
+/*
+ * Oneshot interrupts keep the irq line masked until the threaded
+ * handler finished. unmask if the interrupt has not been disabled and
+ * is marked MASKED.
+ */
+static void irq_finalize_oneshot(struct irq_desc *desc,
+				 struct irqaction *action)
+{
+	if (!(desc->istate & IRQS_ONESHOT) ||
+	    action->handler == irq_forced_secondary_handler)
+		return;
+again:
+	chip_bus_lock(desc);
+	raw_spin_lock_irq(&desc->lock);
+
+	/*
+	 * Implausible though it may be we need to protect us against
+	 * the following scenario:
+	 *
+	 * The thread is faster done than the hard interrupt handler
+	 * on the other CPU. If we unmask the irq line then the
+	 * interrupt can come in again and masks the line, leaves due
+	 * to IRQS_INPROGRESS and the irq line is masked forever.
+	 *
+	 * This also serializes the state of shared oneshot handlers
+	 * versus "desc->threads_oneshot |= action->thread_mask;" in
+	 * irq_wake_thread(). See the comment there which explains the
+	 * serialization.
+	 */
+	if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
+		raw_spin_unlock_irq(&desc->lock);
+		chip_bus_sync_unlock(desc);
+		cpu_relax();
+		goto again;
+	}
+
+	/*
+	 * Now check again, whether the thread should run. Otherwise
+	 * we would clear the threads_oneshot bit of this thread which
+	 * was just set.
+	 */
+	if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+		goto out_unlock;
+
+	desc->threads_oneshot &= ~action->thread_mask;
+
+	if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
+	    irqd_irq_masked(&desc->irq_data))
+		unmask_threaded_irq(desc);
+
+out_unlock:
+	raw_spin_unlock_irq(&desc->lock);
+	chip_bus_sync_unlock(desc);
+}
+
+#ifdef CONFIG_SMP
+/*
+ * Check whether we need to change the affinity of the interrupt thread.
+ */
+static void
+irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
+{
+	cpumask_var_t mask;
+	bool valid = true;
+
+	if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
+		return;
+
+	/*
+	 * In case we are out of memory we set IRQTF_AFFINITY again and
+	 * try again next time
+	 */
+	if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
+		set_bit(IRQTF_AFFINITY, &action->thread_flags);
+		return;
+	}
+
+	raw_spin_lock_irq(&desc->lock);
+	/*
+	 * This code is triggered unconditionally. Check the affinity
+	 * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
+	 */
+	if (cpumask_available(desc->irq_common_data.affinity)) {
+		const struct cpumask *m;
+
+		m = irq_data_get_effective_affinity_mask(&desc->irq_data);
+		cpumask_copy(mask, m);
+	} else {
+		valid = false;
+	}
+	raw_spin_unlock_irq(&desc->lock);
+
+	if (valid)
+		set_cpus_allowed_ptr(current, mask);
+	free_cpumask_var(mask);
+}
+#else
+static inline void
+irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
+#endif
+
+/*
+ * Interrupts which are not explicitly requested as threaded
+ * interrupts rely on the implicit bh/preempt disable of the hard irq
+ * context. So we need to disable bh here to avoid deadlocks and other
+ * side effects.
+ */
+static irqreturn_t
+irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
+{
+	irqreturn_t ret;
+
+	local_bh_disable();
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		local_irq_disable();
+	ret = action->thread_fn(action->irq, action->dev_id);
+	if (ret == IRQ_HANDLED)
+		atomic_inc(&desc->threads_handled);
+
+	irq_finalize_oneshot(desc, action);
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		local_irq_enable();
+	local_bh_enable();
+	return ret;
+}
+
+/*
+ * Interrupts explicitly requested as threaded interrupts want to be
+ * preemptible - many of them need to sleep and wait for slow busses to
+ * complete.
+ */
+static irqreturn_t irq_thread_fn(struct irq_desc *desc,
+		struct irqaction *action)
+{
+	irqreturn_t ret;
+
+	ret = action->thread_fn(action->irq, action->dev_id);
+	if (ret == IRQ_HANDLED)
+		atomic_inc(&desc->threads_handled);
+
+	irq_finalize_oneshot(desc, action);
+	return ret;
+}
+
+static void wake_threads_waitq(struct irq_desc *desc)
+{
+	if (atomic_dec_and_test(&desc->threads_active))
+		wake_up(&desc->wait_for_threads);
+}
+
+static void irq_thread_dtor(struct callback_head *unused)
+{
+	struct task_struct *tsk = current;
+	struct irq_desc *desc;
+	struct irqaction *action;
+
+	if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
+		return;
+
+	action = kthread_data(tsk);
+
+	pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
+	       tsk->comm, tsk->pid, action->irq);
+
+
+	desc = irq_to_desc(action->irq);
+	/*
+	 * If IRQTF_RUNTHREAD is set, we need to decrement
+	 * desc->threads_active and wake possible waiters.
+	 */
+	if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+		wake_threads_waitq(desc);
+
+	/* Prevent a stale desc->threads_oneshot */
+	irq_finalize_oneshot(desc, action);
+}
+
+static void irq_wake_secondary(struct irq_desc *desc, struct irqaction *action)
+{
+	struct irqaction *secondary = action->secondary;
+
+	if (WARN_ON_ONCE(!secondary))
+		return;
+
+	raw_spin_lock_irq(&desc->lock);
+	__irq_wake_thread(desc, secondary);
+	raw_spin_unlock_irq(&desc->lock);
+}
+
+/*
+ * Internal function to notify that a interrupt thread is ready.
+ */
+static void irq_thread_set_ready(struct irq_desc *desc,
+				 struct irqaction *action)
+{
+	set_bit(IRQTF_READY, &action->thread_flags);
+	wake_up(&desc->wait_for_threads);
+}
+
+/*
+ * Internal function to wake up a interrupt thread and wait until it is
+ * ready.
+ */
+static void wake_up_and_wait_for_irq_thread_ready(struct irq_desc *desc,
+						  struct irqaction *action)
+{
+	if (!action || !action->thread)
+		return;
+
+	wake_up_process(action->thread);
+	wait_event(desc->wait_for_threads,
+		   test_bit(IRQTF_READY, &action->thread_flags));
+}
+
+/*
+ * Interrupt handler thread
+ */
+static int irq_thread(void *data)
+{
+	struct callback_head on_exit_work;
+	struct irqaction *action = data;
+	struct irq_desc *desc = irq_to_desc(action->irq);
+	irqreturn_t (*handler_fn)(struct irq_desc *desc,
+			struct irqaction *action);
+
+	irq_thread_set_ready(desc, action);
+
+	sched_set_fifo(current);
+
+	if (force_irqthreads() && test_bit(IRQTF_FORCED_THREAD,
+					   &action->thread_flags))
+		handler_fn = irq_forced_thread_fn;
+	else
+		handler_fn = irq_thread_fn;
+
+	init_task_work(&on_exit_work, irq_thread_dtor);
+	task_work_add(current, &on_exit_work, TWA_NONE);
+
+	irq_thread_check_affinity(desc, action);
+
+	while (!irq_wait_for_interrupt(action)) {
+		irqreturn_t action_ret;
+
+		irq_thread_check_affinity(desc, action);
+
+		action_ret = handler_fn(desc, action);
+		if (action_ret == IRQ_WAKE_THREAD)
+			irq_wake_secondary(desc, action);
+
+		wake_threads_waitq(desc);
+	}
+
+	/*
+	 * This is the regular exit path. __free_irq() is stopping the
+	 * thread via kthread_stop() after calling
+	 * synchronize_hardirq(). So neither IRQTF_RUNTHREAD nor the
+	 * oneshot mask bit can be set.
+	 */
+	task_work_cancel(current, irq_thread_dtor);
+	return 0;
+}
+
+/**
+ *	irq_wake_thread - wake the irq thread for the action identified by dev_id
+ *	@irq:		Interrupt line
+ *	@dev_id:	Device identity for which the thread should be woken
+ *
+ */
+void irq_wake_thread(unsigned int irq, void *dev_id)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	struct irqaction *action;
+	unsigned long flags;
+
+	if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
+		return;
+
+	raw_spin_lock_irqsave(&desc->lock, flags);
+	for_each_action_of_desc(desc, action) {
+		if (action->dev_id == dev_id) {
+			if (action->thread)
+				__irq_wake_thread(desc, action);
+			break;
+		}
+	}
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+}
+EXPORT_SYMBOL_GPL(irq_wake_thread);
+
+static int irq_setup_forced_threading(struct irqaction *new)
+{
+	if (!force_irqthreads())
+		return 0;
+	if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
+		return 0;
+
+	/*
+	 * No further action required for interrupts which are requested as
+	 * threaded interrupts already
+	 */
+	if (new->handler == irq_default_primary_handler)
+		return 0;
+
+	new->flags |= IRQF_ONESHOT;
+
+	/*
+	 * Handle the case where we have a real primary handler and a
+	 * thread handler. We force thread them as well by creating a
+	 * secondary action.
+	 */
+	if (new->handler && new->thread_fn) {
+		/* Allocate the secondary action */
+		new->secondary = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
+		if (!new->secondary)
+			return -ENOMEM;
+		new->secondary->handler = irq_forced_secondary_handler;
+		new->secondary->thread_fn = new->thread_fn;
+		new->secondary->dev_id = new->dev_id;
+		new->secondary->irq = new->irq;
+		new->secondary->name = new->name;
+	}
+	/* Deal with the primary handler */
+	set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
+	new->thread_fn = new->handler;
+	new->handler = irq_default_primary_handler;
+	return 0;
+}
+
+static int irq_request_resources(struct irq_desc *desc)
+{
+	struct irq_data *d = &desc->irq_data;
+	struct irq_chip *c = d->chip;
+
+	return c->irq_request_resources ? c->irq_request_resources(d) : 0;
+}
+
+static void irq_release_resources(struct irq_desc *desc)
+{
+	struct irq_data *d = &desc->irq_data;
+	struct irq_chip *c = d->chip;
+
+	if (c->irq_release_resources)
+		c->irq_release_resources(d);
+}
+
+static bool irq_supports_nmi(struct irq_desc *desc)
+{
+	struct irq_data *d = irq_desc_get_irq_data(desc);
+
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+	/* Only IRQs directly managed by the root irqchip can be set as NMI */
+	if (d->parent_data)
+		return false;
+#endif
+	/* Don't support NMIs for chips behind a slow bus */
+	if (d->chip->irq_bus_lock || d->chip->irq_bus_sync_unlock)
+		return false;
+
+	return d->chip->flags & IRQCHIP_SUPPORTS_NMI;
+}
+
+static int irq_nmi_setup(struct irq_desc *desc)
+{
+	struct irq_data *d = irq_desc_get_irq_data(desc);
+	struct irq_chip *c = d->chip;
+
+	return c->irq_nmi_setup ? c->irq_nmi_setup(d) : -EINVAL;
+}
+
+static void irq_nmi_teardown(struct irq_desc *desc)
+{
+	struct irq_data *d = irq_desc_get_irq_data(desc);
+	struct irq_chip *c = d->chip;
+
+	if (c->irq_nmi_teardown)
+		c->irq_nmi_teardown(d);
+}
+
+static int
+setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
+{
+	struct task_struct *t;
+
+	if (!secondary) {
+		t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
+				   new->name);
+	} else {
+		t = kthread_create(irq_thread, new, "irq/%d-s-%s", irq,
+				   new->name);
+	}
+
+	if (IS_ERR(t))
+		return PTR_ERR(t);
+
+	/*
+	 * We keep the reference to the task struct even if
+	 * the thread dies to avoid that the interrupt code
+	 * references an already freed task_struct.
+	 */
+	new->thread = get_task_struct(t);
+	/*
+	 * Tell the thread to set its affinity. This is
+	 * important for shared interrupt handlers as we do
+	 * not invoke setup_affinity() for the secondary
+	 * handlers as everything is already set up. Even for
+	 * interrupts marked with IRQF_NO_BALANCE this is
+	 * correct as we want the thread to move to the cpu(s)
+	 * on which the requesting code placed the interrupt.
+	 */
+	set_bit(IRQTF_AFFINITY, &new->thread_flags);
+	return 0;
+}
+
+/*
+ * Internal function to register an irqaction - typically used to
+ * allocate special interrupts that are part of the architecture.
+ *
+ * Locking rules:
+ *
+ * desc->request_mutex	Provides serialization against a concurrent free_irq()
+ *   chip_bus_lock	Provides serialization for slow bus operations
+ *     desc->lock	Provides serialization against hard interrupts
+ *
+ * chip_bus_lock and desc->lock are sufficient for all other management and
+ * interrupt related functions. desc->request_mutex solely serializes
+ * request/free_irq().
+ */
+static int
+__setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
+{
+	struct irqaction *old, **old_ptr;
+	unsigned long flags, thread_mask = 0;
+	int ret, nested, shared = 0;
+
+	if (!desc)
+		return -EINVAL;
+
+	if (desc->irq_data.chip == &no_irq_chip)
+		return -ENOSYS;
+	if (!try_module_get(desc->owner))
+		return -ENODEV;
+
+	new->irq = irq;
+
+	/*
+	 * If the trigger type is not specified by the caller,
+	 * then use the default for this interrupt.
+	 */
+	if (!(new->flags & IRQF_TRIGGER_MASK))
+		new->flags |= irqd_get_trigger_type(&desc->irq_data);
+
+	/*
+	 * Check whether the interrupt nests into another interrupt
+	 * thread.
+	 */
+	nested = irq_settings_is_nested_thread(desc);
+	if (nested) {
+		if (!new->thread_fn) {
+			ret = -EINVAL;
+			goto out_mput;
+		}
+		/*
+		 * Replace the primary handler which was provided from
+		 * the driver for non nested interrupt handling by the
+		 * dummy function which warns when called.
+		 */
+		new->handler = irq_nested_primary_handler;
+	} else {
+		if (irq_settings_can_thread(desc)) {
+			ret = irq_setup_forced_threading(new);
+			if (ret)
+				goto out_mput;
+		}
+	}
+
+	/*
+	 * Create a handler thread when a thread function is supplied
+	 * and the interrupt does not nest into another interrupt
+	 * thread.
+	 */
+	if (new->thread_fn && !nested) {
+		ret = setup_irq_thread(new, irq, false);
+		if (ret)
+			goto out_mput;
+		if (new->secondary) {
+			ret = setup_irq_thread(new->secondary, irq, true);
+			if (ret)
+				goto out_thread;
+		}
+	}
+
+	/*
+	 * Drivers are often written to work w/o knowledge about the
+	 * underlying irq chip implementation, so a request for a
+	 * threaded irq without a primary hard irq context handler
+	 * requires the ONESHOT flag to be set. Some irq chips like
+	 * MSI based interrupts are per se one shot safe. Check the
+	 * chip flags, so we can avoid the unmask dance at the end of
+	 * the threaded handler for those.
+	 */
+	if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
+		new->flags &= ~IRQF_ONESHOT;
+
+	/*
+	 * Protects against a concurrent __free_irq() call which might wait
+	 * for synchronize_hardirq() to complete without holding the optional
+	 * chip bus lock and desc->lock. Also protects against handing out
+	 * a recycled oneshot thread_mask bit while it's still in use by
+	 * its previous owner.
+	 */
+	mutex_lock(&desc->request_mutex);
+
+	/*
+	 * Acquire bus lock as the irq_request_resources() callback below
+	 * might rely on the serialization or the magic power management
+	 * functions which are abusing the irq_bus_lock() callback,
+	 */
+	chip_bus_lock(desc);
+
+	/* First installed action requests resources. */
+	if (!desc->action) {
+		ret = irq_request_resources(desc);
+		if (ret) {
+			pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
+			       new->name, irq, desc->irq_data.chip->name);
+			goto out_bus_unlock;
+		}
+	}
+
+	/*
+	 * The following block of code has to be executed atomically
+	 * protected against a concurrent interrupt and any of the other
+	 * management calls which are not serialized via
+	 * desc->request_mutex or the optional bus lock.
+	 */
+	raw_spin_lock_irqsave(&desc->lock, flags);
+	old_ptr = &desc->action;
+	old = *old_ptr;
+	if (old) {
+		/*
+		 * Can't share interrupts unless both agree to and are
+		 * the same type (level, edge, polarity). So both flag
+		 * fields must have IRQF_SHARED set and the bits which
+		 * set the trigger type must match. Also all must
+		 * agree on ONESHOT.
+		 * Interrupt lines used for NMIs cannot be shared.
+		 */
+		unsigned int oldtype;
+
+		if (desc->istate & IRQS_NMI) {
+			pr_err("Invalid attempt to share NMI for %s (irq %d) on irqchip %s.\n",
+				new->name, irq, desc->irq_data.chip->name);
+			ret = -EINVAL;
+			goto out_unlock;
+		}
+
+		/*
+		 * If nobody did set the configuration before, inherit
+		 * the one provided by the requester.
+		 */
+		if (irqd_trigger_type_was_set(&desc->irq_data)) {
+			oldtype = irqd_get_trigger_type(&desc->irq_data);
+		} else {
+			oldtype = new->flags & IRQF_TRIGGER_MASK;
+			irqd_set_trigger_type(&desc->irq_data, oldtype);
+		}
+
+		if (!((old->flags & new->flags) & IRQF_SHARED) ||
+		    (oldtype != (new->flags & IRQF_TRIGGER_MASK)) ||
+		    ((old->flags ^ new->flags) & IRQF_ONESHOT))
+			goto mismatch;
+
+		/* All handlers must agree on per-cpuness */
+		if ((old->flags & IRQF_PERCPU) !=
+		    (new->flags & IRQF_PERCPU))
+			goto mismatch;
+
+		/* add new interrupt at end of irq queue */
+		do {
+			/*
+			 * Or all existing action->thread_mask bits,
+			 * so we can find the next zero bit for this
+			 * new action.
+			 */
+			thread_mask |= old->thread_mask;
+			old_ptr = &old->next;
+			old = *old_ptr;
+		} while (old);
+		shared = 1;
+	}
+
+	/*
+	 * Setup the thread mask for this irqaction for ONESHOT. For
+	 * !ONESHOT irqs the thread mask is 0 so we can avoid a
+	 * conditional in irq_wake_thread().
+	 */
+	if (new->flags & IRQF_ONESHOT) {
+		/*
+		 * Unlikely to have 32 resp 64 irqs sharing one line,
+		 * but who knows.
+		 */
+		if (thread_mask == ~0UL) {
+			ret = -EBUSY;
+			goto out_unlock;
+		}
+		/*
+		 * The thread_mask for the action is or'ed to
+		 * desc->thread_active to indicate that the
+		 * IRQF_ONESHOT thread handler has been woken, but not
+		 * yet finished. The bit is cleared when a thread
+		 * completes. When all threads of a shared interrupt
+		 * line have completed desc->threads_active becomes
+		 * zero and the interrupt line is unmasked. See
+		 * handle.c:irq_wake_thread() for further information.
+		 *
+		 * If no thread is woken by primary (hard irq context)
+		 * interrupt handlers, then desc->threads_active is
+		 * also checked for zero to unmask the irq line in the
+		 * affected hard irq flow handlers
+		 * (handle_[fasteoi|level]_irq).
+		 *
+		 * The new action gets the first zero bit of
+		 * thread_mask assigned. See the loop above which or's
+		 * all existing action->thread_mask bits.
+		 */
+		new->thread_mask = 1UL << ffz(thread_mask);
+
+	} else if (new->handler == irq_default_primary_handler &&
+		   !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
+		/*
+		 * The interrupt was requested with handler = NULL, so
+		 * we use the default primary handler for it. But it
+		 * does not have the oneshot flag set. In combination
+		 * with level interrupts this is deadly, because the
+		 * default primary handler just wakes the thread, then
+		 * the irq lines is reenabled, but the device still
+		 * has the level irq asserted. Rinse and repeat....
+		 *
+		 * While this works for edge type interrupts, we play
+		 * it safe and reject unconditionally because we can't
+		 * say for sure which type this interrupt really
+		 * has. The type flags are unreliable as the
+		 * underlying chip implementation can override them.
+		 */
+		pr_err("Threaded irq requested with handler=NULL and !ONESHOT for %s (irq %d)\n",
+		       new->name, irq);
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	if (!shared) {
+		/* Setup the type (level, edge polarity) if configured: */
+		if (new->flags & IRQF_TRIGGER_MASK) {
+			ret = __irq_set_trigger(desc,
+						new->flags & IRQF_TRIGGER_MASK);
+
+			if (ret)
+				goto out_unlock;
+		}
+
+		/*
+		 * Activate the interrupt. That activation must happen
+		 * independently of IRQ_NOAUTOEN. request_irq() can fail
+		 * and the callers are supposed to handle
+		 * that. enable_irq() of an interrupt requested with
+		 * IRQ_NOAUTOEN is not supposed to fail. The activation
+		 * keeps it in shutdown mode, it merily associates
+		 * resources if necessary and if that's not possible it
+		 * fails. Interrupts which are in managed shutdown mode
+		 * will simply ignore that activation request.
+		 */
+		ret = irq_activate(desc);
+		if (ret)
+			goto out_unlock;
+
+		desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
+				  IRQS_ONESHOT | IRQS_WAITING);
+		irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
+
+		if (new->flags & IRQF_PERCPU) {
+			irqd_set(&desc->irq_data, IRQD_PER_CPU);
+			irq_settings_set_per_cpu(desc);
+			if (new->flags & IRQF_NO_DEBUG)
+				irq_settings_set_no_debug(desc);
+		}
+
+		if (noirqdebug)
+			irq_settings_set_no_debug(desc);
+
+		if (new->flags & IRQF_ONESHOT)
+			desc->istate |= IRQS_ONESHOT;
+
+		/* Exclude IRQ from balancing if requested */
+		if (new->flags & IRQF_NOBALANCING) {
+			irq_settings_set_no_balancing(desc);
+			irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
+		}
+
+		if (!(new->flags & IRQF_NO_AUTOEN) &&
+		    irq_settings_can_autoenable(desc)) {
+			irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
+		} else {
+			/*
+			 * Shared interrupts do not go well with disabling
+			 * auto enable. The sharing interrupt might request
+			 * it while it's still disabled and then wait for
+			 * interrupts forever.
+			 */
+			WARN_ON_ONCE(new->flags & IRQF_SHARED);
+			/* Undo nested disables: */
+			desc->depth = 1;
+		}
+
+	} else if (new->flags & IRQF_TRIGGER_MASK) {
+		unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
+		unsigned int omsk = irqd_get_trigger_type(&desc->irq_data);
+
+		if (nmsk != omsk)
+			/* hope the handler works with current  trigger mode */
+			pr_warn("irq %d uses trigger mode %u; requested %u\n",
+				irq, omsk, nmsk);
+	}
+
+	*old_ptr = new;
+
+	irq_pm_install_action(desc, new);
+
+	/* Reset broken irq detection when installing new handler */
+	desc->irq_count = 0;
+	desc->irqs_unhandled = 0;
+
+	/*
+	 * Check whether we disabled the irq via the spurious handler
+	 * before. Reenable it and give it another chance.
+	 */
+	if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
+		desc->istate &= ~IRQS_SPURIOUS_DISABLED;
+		__enable_irq(desc);
+	}
+
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+	chip_bus_sync_unlock(desc);
+	mutex_unlock(&desc->request_mutex);
+
+	irq_setup_timings(desc, new);
+
+	wake_up_and_wait_for_irq_thread_ready(desc, new);
+	wake_up_and_wait_for_irq_thread_ready(desc, new->secondary);
+
+	register_irq_proc(irq, desc);
+	new->dir = NULL;
+	register_handler_proc(irq, new);
+	return 0;
+
+mismatch:
+	if (!(new->flags & IRQF_PROBE_SHARED)) {
+		pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
+		       irq, new->flags, new->name, old->flags, old->name);
+#ifdef CONFIG_DEBUG_SHIRQ
+		dump_stack();
+#endif
+	}
+	ret = -EBUSY;
+
+out_unlock:
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+	if (!desc->action)
+		irq_release_resources(desc);
+out_bus_unlock:
+	chip_bus_sync_unlock(desc);
+	mutex_unlock(&desc->request_mutex);
+
+out_thread:
+	if (new->thread) {
+		struct task_struct *t = new->thread;
+
+		new->thread = NULL;
+		kthread_stop(t);
+		put_task_struct(t);
+	}
+	if (new->secondary && new->secondary->thread) {
+		struct task_struct *t = new->secondary->thread;
+
+		new->secondary->thread = NULL;
+		kthread_stop(t);
+		put_task_struct(t);
+	}
+out_mput:
+	module_put(desc->owner);
+	return ret;
+}
+
+/*
+ * Internal function to unregister an irqaction - used to free
+ * regular and special interrupts that are part of the architecture.
+ */
+static struct irqaction *__free_irq(struct irq_desc *desc, void *dev_id)
+{
+	unsigned irq = desc->irq_data.irq;
+	struct irqaction *action, **action_ptr;
+	unsigned long flags;
+
+	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
+
+	mutex_lock(&desc->request_mutex);
+	chip_bus_lock(desc);
+	raw_spin_lock_irqsave(&desc->lock, flags);
+
+	/*
+	 * There can be multiple actions per IRQ descriptor, find the right
+	 * one based on the dev_id:
+	 */
+	action_ptr = &desc->action;
+	for (;;) {
+		action = *action_ptr;
+
+		if (!action) {
+			WARN(1, "Trying to free already-free IRQ %d\n", irq);
+			raw_spin_unlock_irqrestore(&desc->lock, flags);
+			chip_bus_sync_unlock(desc);
+			mutex_unlock(&desc->request_mutex);
+			return NULL;
+		}
+
+		if (action->dev_id == dev_id)
+			break;
+		action_ptr = &action->next;
+	}
+
+	/* Found it - now remove it from the list of entries: */
+	*action_ptr = action->next;
+
+	irq_pm_remove_action(desc, action);
+
+	/* If this was the last handler, shut down the IRQ line: */
+	if (!desc->action) {
+		irq_settings_clr_disable_unlazy(desc);
+		/* Only shutdown. Deactivate after synchronize_hardirq() */
+		irq_shutdown(desc);
+	}
+
+#ifdef CONFIG_SMP
+	/* make sure affinity_hint is cleaned up */
+	if (WARN_ON_ONCE(desc->affinity_hint))
+		desc->affinity_hint = NULL;
+#endif
+
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+	/*
+	 * Drop bus_lock here so the changes which were done in the chip
+	 * callbacks above are synced out to the irq chips which hang
+	 * behind a slow bus (I2C, SPI) before calling synchronize_hardirq().
+	 *
+	 * Aside of that the bus_lock can also be taken from the threaded
+	 * handler in irq_finalize_oneshot() which results in a deadlock
+	 * because kthread_stop() would wait forever for the thread to
+	 * complete, which is blocked on the bus lock.
+	 *
+	 * The still held desc->request_mutex() protects against a
+	 * concurrent request_irq() of this irq so the release of resources
+	 * and timing data is properly serialized.
+	 */
+	chip_bus_sync_unlock(desc);
+
+	unregister_handler_proc(irq, action);
+
+	/*
+	 * Make sure it's not being used on another CPU and if the chip
+	 * supports it also make sure that there is no (not yet serviced)
+	 * interrupt in flight at the hardware level.
+	 */
+	__synchronize_hardirq(desc, true);
+
+#ifdef CONFIG_DEBUG_SHIRQ
+	/*
+	 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
+	 * event to happen even now it's being freed, so let's make sure that
+	 * is so by doing an extra call to the handler ....
+	 *
+	 * ( We do this after actually deregistering it, to make sure that a
+	 *   'real' IRQ doesn't run in parallel with our fake. )
+	 */
+	if (action->flags & IRQF_SHARED) {
+		local_irq_save(flags);
+		action->handler(irq, dev_id);
+		local_irq_restore(flags);
+	}
+#endif
+
+	/*
+	 * The action has already been removed above, but the thread writes
+	 * its oneshot mask bit when it completes. Though request_mutex is
+	 * held across this which prevents __setup_irq() from handing out
+	 * the same bit to a newly requested action.
+	 */
+	if (action->thread) {
+		kthread_stop(action->thread);
+		put_task_struct(action->thread);
+		if (action->secondary && action->secondary->thread) {
+			kthread_stop(action->secondary->thread);
+			put_task_struct(action->secondary->thread);
+		}
+	}
+
+	/* Last action releases resources */
+	if (!desc->action) {
+		/*
+		 * Reacquire bus lock as irq_release_resources() might
+		 * require it to deallocate resources over the slow bus.
+		 */
+		chip_bus_lock(desc);
+		/*
+		 * There is no interrupt on the fly anymore. Deactivate it
+		 * completely.
+		 */
+		raw_spin_lock_irqsave(&desc->lock, flags);
+		irq_domain_deactivate_irq(&desc->irq_data);
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+		irq_release_resources(desc);
+		chip_bus_sync_unlock(desc);
+		irq_remove_timings(desc);
+	}
+
+	mutex_unlock(&desc->request_mutex);
+
+	irq_chip_pm_put(&desc->irq_data);
+	module_put(desc->owner);
+	kfree(action->secondary);
+	return action;
+}
+
+/**
+ *	free_irq - free an interrupt allocated with request_irq
+ *	@irq: Interrupt line to free
+ *	@dev_id: Device identity to free
+ *
+ *	Remove an interrupt handler. The handler is removed and if the
+ *	interrupt line is no longer in use by any driver it is disabled.
+ *	On a shared IRQ the caller must ensure the interrupt is disabled
+ *	on the card it drives before calling this function. The function
+ *	does not return until any executing interrupts for this IRQ
+ *	have completed.
+ *
+ *	This function must not be called from interrupt context.
+ *
+ *	Returns the devname argument passed to request_irq.
+ */
+const void *free_irq(unsigned int irq, void *dev_id)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	struct irqaction *action;
+	const char *devname;
+
+	if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
+		return NULL;
+
+#ifdef CONFIG_SMP
+	if (WARN_ON(desc->affinity_notify))
+		desc->affinity_notify = NULL;
+#endif
+
+	action = __free_irq(desc, dev_id);
+
+	if (!action)
+		return NULL;
+
+	devname = action->name;
+	kfree(action);
+	return devname;
+}
+EXPORT_SYMBOL(free_irq);
+
+/* This function must be called with desc->lock held */
+static const void *__cleanup_nmi(unsigned int irq, struct irq_desc *desc)
+{
+	const char *devname = NULL;
+
+	desc->istate &= ~IRQS_NMI;
+
+	if (!WARN_ON(desc->action == NULL)) {
+		irq_pm_remove_action(desc, desc->action);
+		devname = desc->action->name;
+		unregister_handler_proc(irq, desc->action);
+
+		kfree(desc->action);
+		desc->action = NULL;
+	}
+
+	irq_settings_clr_disable_unlazy(desc);
+	irq_shutdown_and_deactivate(desc);
+
+	irq_release_resources(desc);
+
+	irq_chip_pm_put(&desc->irq_data);
+	module_put(desc->owner);
+
+	return devname;
+}
+
+const void *free_nmi(unsigned int irq, void *dev_id)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	unsigned long flags;
+	const void *devname;
+
+	if (!desc || WARN_ON(!(desc->istate & IRQS_NMI)))
+		return NULL;
+
+	if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
+		return NULL;
+
+	/* NMI still enabled */
+	if (WARN_ON(desc->depth == 0))
+		disable_nmi_nosync(irq);
+
+	raw_spin_lock_irqsave(&desc->lock, flags);
+
+	irq_nmi_teardown(desc);
+	devname = __cleanup_nmi(irq, desc);
+
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+	return devname;
+}
+
+/**
+ *	request_threaded_irq - allocate an interrupt line
+ *	@irq: Interrupt line to allocate
+ *	@handler: Function to be called when the IRQ occurs.
+ *		  Primary handler for threaded interrupts.
+ *		  If handler is NULL and thread_fn != NULL
+ *		  the default primary handler is installed.
+ *	@thread_fn: Function called from the irq handler thread
+ *		    If NULL, no irq thread is created
+ *	@irqflags: Interrupt type flags
+ *	@devname: An ascii name for the claiming device
+ *	@dev_id: A cookie passed back to the handler function
+ *
+ *	This call allocates interrupt resources and enables the
+ *	interrupt line and IRQ handling. From the point this
+ *	call is made your handler function may be invoked. Since
+ *	your handler function must clear any interrupt the board
+ *	raises, you must take care both to initialise your hardware
+ *	and to set up the interrupt handler in the right order.
+ *
+ *	If you want to set up a threaded irq handler for your device
+ *	then you need to supply @handler and @thread_fn. @handler is
+ *	still called in hard interrupt context and has to check
+ *	whether the interrupt originates from the device. If yes it
+ *	needs to disable the interrupt on the device and return
+ *	IRQ_WAKE_THREAD which will wake up the handler thread and run
+ *	@thread_fn. This split handler design is necessary to support
+ *	shared interrupts.
+ *
+ *	Dev_id must be globally unique. Normally the address of the
+ *	device data structure is used as the cookie. Since the handler
+ *	receives this value it makes sense to use it.
+ *
+ *	If your interrupt is shared you must pass a non NULL dev_id
+ *	as this is required when freeing the interrupt.
+ *
+ *	Flags:
+ *
+ *	IRQF_SHARED		Interrupt is shared
+ *	IRQF_TRIGGER_*		Specify active edge(s) or level
+ *	IRQF_ONESHOT		Run thread_fn with interrupt line masked
+ */
+int request_threaded_irq(unsigned int irq, irq_handler_t handler,
+			 irq_handler_t thread_fn, unsigned long irqflags,
+			 const char *devname, void *dev_id)
+{
+	struct irqaction *action;
+	struct irq_desc *desc;
+	int retval;
+
+	if (irq == IRQ_NOTCONNECTED)
+		return -ENOTCONN;
+
+	/*
+	 * Sanity-check: shared interrupts must pass in a real dev-ID,
+	 * otherwise we'll have trouble later trying to figure out
+	 * which interrupt is which (messes up the interrupt freeing
+	 * logic etc).
+	 *
+	 * Also shared interrupts do not go well with disabling auto enable.
+	 * The sharing interrupt might request it while it's still disabled
+	 * and then wait for interrupts forever.
+	 *
+	 * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
+	 * it cannot be set along with IRQF_NO_SUSPEND.
+	 */
+	if (((irqflags & IRQF_SHARED) && !dev_id) ||
+	    ((irqflags & IRQF_SHARED) && (irqflags & IRQF_NO_AUTOEN)) ||
+	    (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
+	    ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
+		return -EINVAL;
+
+	desc = irq_to_desc(irq);
+	if (!desc)
+		return -EINVAL;
+
+	if (!irq_settings_can_request(desc) ||
+	    WARN_ON(irq_settings_is_per_cpu_devid(desc)))
+		return -EINVAL;
+
+	if (!handler) {
+		if (!thread_fn)
+			return -EINVAL;
+		handler = irq_default_primary_handler;
+	}
+
+	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
+	if (!action)
+		return -ENOMEM;
+
+	action->handler = handler;
+	action->thread_fn = thread_fn;
+	action->flags = irqflags;
+	action->name = devname;
+	action->dev_id = dev_id;
+
+	retval = irq_chip_pm_get(&desc->irq_data);
+	if (retval < 0) {
+		kfree(action);
+		return retval;
+	}
+
+	retval = __setup_irq(irq, desc, action);
+
+	if (retval) {
+		irq_chip_pm_put(&desc->irq_data);
+		kfree(action->secondary);
+		kfree(action);
+	}
+
+#ifdef CONFIG_DEBUG_SHIRQ_FIXME
+	if (!retval && (irqflags & IRQF_SHARED)) {
+		/*
+		 * It's a shared IRQ -- the driver ought to be prepared for it
+		 * to happen immediately, so let's make sure....
+		 * We disable the irq to make sure that a 'real' IRQ doesn't
+		 * run in parallel with our fake.
+		 */
+		unsigned long flags;
+
+		disable_irq(irq);
+		local_irq_save(flags);
+
+		handler(irq, dev_id);
+
+		local_irq_restore(flags);
+		enable_irq(irq);
+	}
+#endif
+	return retval;
+}
+EXPORT_SYMBOL(request_threaded_irq);
+
+/**
+ *	request_any_context_irq - allocate an interrupt line
+ *	@irq: Interrupt line to allocate
+ *	@handler: Function to be called when the IRQ occurs.
+ *		  Threaded handler for threaded interrupts.
+ *	@flags: Interrupt type flags
+ *	@name: An ascii name for the claiming device
+ *	@dev_id: A cookie passed back to the handler function
+ *
+ *	This call allocates interrupt resources and enables the
+ *	interrupt line and IRQ handling. It selects either a
+ *	hardirq or threaded handling method depending on the
+ *	context.
+ *
+ *	On failure, it returns a negative value. On success,
+ *	it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
+ */
+int request_any_context_irq(unsigned int irq, irq_handler_t handler,
+			    unsigned long flags, const char *name, void *dev_id)
+{
+	struct irq_desc *desc;
+	int ret;
+
+	if (irq == IRQ_NOTCONNECTED)
+		return -ENOTCONN;
+
+	desc = irq_to_desc(irq);
+	if (!desc)
+		return -EINVAL;
+
+	if (irq_settings_is_nested_thread(desc)) {
+		ret = request_threaded_irq(irq, NULL, handler,
+					   flags, name, dev_id);
+		return !ret ? IRQC_IS_NESTED : ret;
+	}
+
+	ret = request_irq(irq, handler, flags, name, dev_id);
+	return !ret ? IRQC_IS_HARDIRQ : ret;
+}
+EXPORT_SYMBOL_GPL(request_any_context_irq);
+
+/**
+ *	request_nmi - allocate an interrupt line for NMI delivery
+ *	@irq: Interrupt line to allocate
+ *	@handler: Function to be called when the IRQ occurs.
+ *		  Threaded handler for threaded interrupts.
+ *	@irqflags: Interrupt type flags
+ *	@name: An ascii name for the claiming device
+ *	@dev_id: A cookie passed back to the handler function
+ *
+ *	This call allocates interrupt resources and enables the
+ *	interrupt line and IRQ handling. It sets up the IRQ line
+ *	to be handled as an NMI.
+ *
+ *	An interrupt line delivering NMIs cannot be shared and IRQ handling
+ *	cannot be threaded.
+ *
+ *	Interrupt lines requested for NMI delivering must produce per cpu
+ *	interrupts and have auto enabling setting disabled.
+ *
+ *	Dev_id must be globally unique. Normally the address of the
+ *	device data structure is used as the cookie. Since the handler
+ *	receives this value it makes sense to use it.
+ *
+ *	If the interrupt line cannot be used to deliver NMIs, function
+ *	will fail and return a negative value.
+ */
+int request_nmi(unsigned int irq, irq_handler_t handler,
+		unsigned long irqflags, const char *name, void *dev_id)
+{
+	struct irqaction *action;
+	struct irq_desc *desc;
+	unsigned long flags;
+	int retval;
+
+	if (irq == IRQ_NOTCONNECTED)
+		return -ENOTCONN;
+
+	/* NMI cannot be shared, used for Polling */
+	if (irqflags & (IRQF_SHARED | IRQF_COND_SUSPEND | IRQF_IRQPOLL))
+		return -EINVAL;
+
+	if (!(irqflags & IRQF_PERCPU))
+		return -EINVAL;
+
+	if (!handler)
+		return -EINVAL;
+
+	desc = irq_to_desc(irq);
+
+	if (!desc || (irq_settings_can_autoenable(desc) &&
+	    !(irqflags & IRQF_NO_AUTOEN)) ||
+	    !irq_settings_can_request(desc) ||
+	    WARN_ON(irq_settings_is_per_cpu_devid(desc)) ||
+	    !irq_supports_nmi(desc))
+		return -EINVAL;
+
+	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
+	if (!action)
+		return -ENOMEM;
+
+	action->handler = handler;
+	action->flags = irqflags | IRQF_NO_THREAD | IRQF_NOBALANCING;
+	action->name = name;
+	action->dev_id = dev_id;
+
+	retval = irq_chip_pm_get(&desc->irq_data);
+	if (retval < 0)
+		goto err_out;
+
+	retval = __setup_irq(irq, desc, action);
+	if (retval)
+		goto err_irq_setup;
+
+	raw_spin_lock_irqsave(&desc->lock, flags);
+
+	/* Setup NMI state */
+	desc->istate |= IRQS_NMI;
+	retval = irq_nmi_setup(desc);
+	if (retval) {
+		__cleanup_nmi(irq, desc);
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+		return -EINVAL;
+	}
+
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+	return 0;
+
+err_irq_setup:
+	irq_chip_pm_put(&desc->irq_data);
+err_out:
+	kfree(action);
+
+	return retval;
+}
+
+void enable_percpu_irq(unsigned int irq, unsigned int type)
+{
+	unsigned int cpu = smp_processor_id();
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
+
+	if (!desc)
+		return;
+
+	/*
+	 * If the trigger type is not specified by the caller, then
+	 * use the default for this interrupt.
+	 */
+	type &= IRQ_TYPE_SENSE_MASK;
+	if (type == IRQ_TYPE_NONE)
+		type = irqd_get_trigger_type(&desc->irq_data);
+
+	if (type != IRQ_TYPE_NONE) {
+		int ret;
+
+		ret = __irq_set_trigger(desc, type);
+
+		if (ret) {
+			WARN(1, "failed to set type for IRQ%d\n", irq);
+			goto out;
+		}
+	}
+
+	irq_percpu_enable(desc, cpu);
+out:
+	irq_put_desc_unlock(desc, flags);
+}
+EXPORT_SYMBOL_GPL(enable_percpu_irq);
+
+void enable_percpu_nmi(unsigned int irq, unsigned int type)
+{
+	enable_percpu_irq(irq, type);
+}
+
+/**
+ * irq_percpu_is_enabled - Check whether the per cpu irq is enabled
+ * @irq:	Linux irq number to check for
+ *
+ * Must be called from a non migratable context. Returns the enable
+ * state of a per cpu interrupt on the current cpu.
+ */
+bool irq_percpu_is_enabled(unsigned int irq)
+{
+	unsigned int cpu = smp_processor_id();
+	struct irq_desc *desc;
+	unsigned long flags;
+	bool is_enabled;
+
+	desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
+	if (!desc)
+		return false;
+
+	is_enabled = cpumask_test_cpu(cpu, desc->percpu_enabled);
+	irq_put_desc_unlock(desc, flags);
+
+	return is_enabled;
+}
+EXPORT_SYMBOL_GPL(irq_percpu_is_enabled);
+
+void disable_percpu_irq(unsigned int irq)
+{
+	unsigned int cpu = smp_processor_id();
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
+
+	if (!desc)
+		return;
+
+	irq_percpu_disable(desc, cpu);
+	irq_put_desc_unlock(desc, flags);
+}
+EXPORT_SYMBOL_GPL(disable_percpu_irq);
+
+void disable_percpu_nmi(unsigned int irq)
+{
+	disable_percpu_irq(irq);
+}
+
+/*
+ * Internal function to unregister a percpu irqaction.
+ */
+static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	struct irqaction *action;
+	unsigned long flags;
+
+	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
+
+	if (!desc)
+		return NULL;
+
+	raw_spin_lock_irqsave(&desc->lock, flags);
+
+	action = desc->action;
+	if (!action || action->percpu_dev_id != dev_id) {
+		WARN(1, "Trying to free already-free IRQ %d\n", irq);
+		goto bad;
+	}
+
+	if (!cpumask_empty(desc->percpu_enabled)) {
+		WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
+		     irq, cpumask_first(desc->percpu_enabled));
+		goto bad;
+	}
+
+	/* Found it - now remove it from the list of entries: */
+	desc->action = NULL;
+
+	desc->istate &= ~IRQS_NMI;
+
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+	unregister_handler_proc(irq, action);
+
+	irq_chip_pm_put(&desc->irq_data);
+	module_put(desc->owner);
+	return action;
+
+bad:
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+	return NULL;
+}
+
+/**
+ *	remove_percpu_irq - free a per-cpu interrupt
+ *	@irq: Interrupt line to free
+ *	@act: irqaction for the interrupt
+ *
+ * Used to remove interrupts statically setup by the early boot process.
+ */
+void remove_percpu_irq(unsigned int irq, struct irqaction *act)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	if (desc && irq_settings_is_per_cpu_devid(desc))
+	    __free_percpu_irq(irq, act->percpu_dev_id);
+}
+
+/**
+ *	free_percpu_irq - free an interrupt allocated with request_percpu_irq
+ *	@irq: Interrupt line to free
+ *	@dev_id: Device identity to free
+ *
+ *	Remove a percpu interrupt handler. The handler is removed, but
+ *	the interrupt line is not disabled. This must be done on each
+ *	CPU before calling this function. The function does not return
+ *	until any executing interrupts for this IRQ have completed.
+ *
+ *	This function must not be called from interrupt context.
+ */
+void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	if (!desc || !irq_settings_is_per_cpu_devid(desc))
+		return;
+
+	chip_bus_lock(desc);
+	kfree(__free_percpu_irq(irq, dev_id));
+	chip_bus_sync_unlock(desc);
+}
+EXPORT_SYMBOL_GPL(free_percpu_irq);
+
+void free_percpu_nmi(unsigned int irq, void __percpu *dev_id)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	if (!desc || !irq_settings_is_per_cpu_devid(desc))
+		return;
+
+	if (WARN_ON(!(desc->istate & IRQS_NMI)))
+		return;
+
+	kfree(__free_percpu_irq(irq, dev_id));
+}
+
+/**
+ *	setup_percpu_irq - setup a per-cpu interrupt
+ *	@irq: Interrupt line to setup
+ *	@act: irqaction for the interrupt
+ *
+ * Used to statically setup per-cpu interrupts in the early boot process.
+ */
+int setup_percpu_irq(unsigned int irq, struct irqaction *act)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	int retval;
+
+	if (!desc || !irq_settings_is_per_cpu_devid(desc))
+		return -EINVAL;
+
+	retval = irq_chip_pm_get(&desc->irq_data);
+	if (retval < 0)
+		return retval;
+
+	retval = __setup_irq(irq, desc, act);
+
+	if (retval)
+		irq_chip_pm_put(&desc->irq_data);
+
+	return retval;
+}
+
+/**
+ *	__request_percpu_irq - allocate a percpu interrupt line
+ *	@irq: Interrupt line to allocate
+ *	@handler: Function to be called when the IRQ occurs.
+ *	@flags: Interrupt type flags (IRQF_TIMER only)
+ *	@devname: An ascii name for the claiming device
+ *	@dev_id: A percpu cookie passed back to the handler function
+ *
+ *	This call allocates interrupt resources and enables the
+ *	interrupt on the local CPU. If the interrupt is supposed to be
+ *	enabled on other CPUs, it has to be done on each CPU using
+ *	enable_percpu_irq().
+ *
+ *	Dev_id must be globally unique. It is a per-cpu variable, and
+ *	the handler gets called with the interrupted CPU's instance of
+ *	that variable.
+ */
+int __request_percpu_irq(unsigned int irq, irq_handler_t handler,
+			 unsigned long flags, const char *devname,
+			 void __percpu *dev_id)
+{
+	struct irqaction *action;
+	struct irq_desc *desc;
+	int retval;
+
+	if (!dev_id)
+		return -EINVAL;
+
+	desc = irq_to_desc(irq);
+	if (!desc || !irq_settings_can_request(desc) ||
+	    !irq_settings_is_per_cpu_devid(desc))
+		return -EINVAL;
+
+	if (flags && flags != IRQF_TIMER)
+		return -EINVAL;
+
+	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
+	if (!action)
+		return -ENOMEM;
+
+	action->handler = handler;
+	action->flags = flags | IRQF_PERCPU | IRQF_NO_SUSPEND;
+	action->name = devname;
+	action->percpu_dev_id = dev_id;
+
+	retval = irq_chip_pm_get(&desc->irq_data);
+	if (retval < 0) {
+		kfree(action);
+		return retval;
+	}
+
+	retval = __setup_irq(irq, desc, action);
+
+	if (retval) {
+		irq_chip_pm_put(&desc->irq_data);
+		kfree(action);
+	}
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(__request_percpu_irq);
+
+/**
+ *	request_percpu_nmi - allocate a percpu interrupt line for NMI delivery
+ *	@irq: Interrupt line to allocate
+ *	@handler: Function to be called when the IRQ occurs.
+ *	@name: An ascii name for the claiming device
+ *	@dev_id: A percpu cookie passed back to the handler function
+ *
+ *	This call allocates interrupt resources for a per CPU NMI. Per CPU NMIs
+ *	have to be setup on each CPU by calling prepare_percpu_nmi() before
+ *	being enabled on the same CPU by using enable_percpu_nmi().
+ *
+ *	Dev_id must be globally unique. It is a per-cpu variable, and
+ *	the handler gets called with the interrupted CPU's instance of
+ *	that variable.
+ *
+ *	Interrupt lines requested for NMI delivering should have auto enabling
+ *	setting disabled.
+ *
+ *	If the interrupt line cannot be used to deliver NMIs, function
+ *	will fail returning a negative value.
+ */
+int request_percpu_nmi(unsigned int irq, irq_handler_t handler,
+		       const char *name, void __percpu *dev_id)
+{
+	struct irqaction *action;
+	struct irq_desc *desc;
+	unsigned long flags;
+	int retval;
+
+	if (!handler)
+		return -EINVAL;
+
+	desc = irq_to_desc(irq);
+
+	if (!desc || !irq_settings_can_request(desc) ||
+	    !irq_settings_is_per_cpu_devid(desc) ||
+	    irq_settings_can_autoenable(desc) ||
+	    !irq_supports_nmi(desc))
+		return -EINVAL;
+
+	/* The line cannot already be NMI */
+	if (desc->istate & IRQS_NMI)
+		return -EINVAL;
+
+	action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
+	if (!action)
+		return -ENOMEM;
+
+	action->handler = handler;
+	action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND | IRQF_NO_THREAD
+		| IRQF_NOBALANCING;
+	action->name = name;
+	action->percpu_dev_id = dev_id;
+
+	retval = irq_chip_pm_get(&desc->irq_data);
+	if (retval < 0)
+		goto err_out;
+
+	retval = __setup_irq(irq, desc, action);
+	if (retval)
+		goto err_irq_setup;
+
+	raw_spin_lock_irqsave(&desc->lock, flags);
+	desc->istate |= IRQS_NMI;
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+	return 0;
+
+err_irq_setup:
+	irq_chip_pm_put(&desc->irq_data);
+err_out:
+	kfree(action);
+
+	return retval;
+}
+
+/**
+ *	prepare_percpu_nmi - performs CPU local setup for NMI delivery
+ *	@irq: Interrupt line to prepare for NMI delivery
+ *
+ *	This call prepares an interrupt line to deliver NMI on the current CPU,
+ *	before that interrupt line gets enabled with enable_percpu_nmi().
+ *
+ *	As a CPU local operation, this should be called from non-preemptible
+ *	context.
+ *
+ *	If the interrupt line cannot be used to deliver NMIs, function
+ *	will fail returning a negative value.
+ */
+int prepare_percpu_nmi(unsigned int irq)
+{
+	unsigned long flags;
+	struct irq_desc *desc;
+	int ret = 0;
+
+	WARN_ON(preemptible());
+
+	desc = irq_get_desc_lock(irq, &flags,
+				 IRQ_GET_DESC_CHECK_PERCPU);
+	if (!desc)
+		return -EINVAL;
+
+	if (WARN(!(desc->istate & IRQS_NMI),
+		 KERN_ERR "prepare_percpu_nmi called for a non-NMI interrupt: irq %u\n",
+		 irq)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = irq_nmi_setup(desc);
+	if (ret) {
+		pr_err("Failed to setup NMI delivery: irq %u\n", irq);
+		goto out;
+	}
+
+out:
+	irq_put_desc_unlock(desc, flags);
+	return ret;
+}
+
+/**
+ *	teardown_percpu_nmi - undoes NMI setup of IRQ line
+ *	@irq: Interrupt line from which CPU local NMI configuration should be
+ *	      removed
+ *
+ *	This call undoes the setup done by prepare_percpu_nmi().
+ *
+ *	IRQ line should not be enabled for the current CPU.
+ *
+ *	As a CPU local operation, this should be called from non-preemptible
+ *	context.
+ */
+void teardown_percpu_nmi(unsigned int irq)
+{
+	unsigned long flags;
+	struct irq_desc *desc;
+
+	WARN_ON(preemptible());
+
+	desc = irq_get_desc_lock(irq, &flags,
+				 IRQ_GET_DESC_CHECK_PERCPU);
+	if (!desc)
+		return;
+
+	if (WARN_ON(!(desc->istate & IRQS_NMI)))
+		goto out;
+
+	irq_nmi_teardown(desc);
+out:
+	irq_put_desc_unlock(desc, flags);
+}
+
+int __irq_get_irqchip_state(struct irq_data *data, enum irqchip_irq_state which,
+			    bool *state)
+{
+	struct irq_chip *chip;
+	int err = -EINVAL;
+
+	do {
+		chip = irq_data_get_irq_chip(data);
+		if (WARN_ON_ONCE(!chip))
+			return -ENODEV;
+		if (chip->irq_get_irqchip_state)
+			break;
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+		data = data->parent_data;
+#else
+		data = NULL;
+#endif
+	} while (data);
+
+	if (data)
+		err = chip->irq_get_irqchip_state(data, which, state);
+	return err;
+}
+
+/**
+ *	irq_get_irqchip_state - returns the irqchip state of a interrupt.
+ *	@irq: Interrupt line that is forwarded to a VM
+ *	@which: One of IRQCHIP_STATE_* the caller wants to know about
+ *	@state: a pointer to a boolean where the state is to be stored
+ *
+ *	This call snapshots the internal irqchip state of an
+ *	interrupt, returning into @state the bit corresponding to
+ *	stage @which
+ *
+ *	This function should be called with preemption disabled if the
+ *	interrupt controller has per-cpu registers.
+ */
+int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
+			  bool *state)
+{
+	struct irq_desc *desc;
+	struct irq_data *data;
+	unsigned long flags;
+	int err = -EINVAL;
+
+	desc = irq_get_desc_buslock(irq, &flags, 0);
+	if (!desc)
+		return err;
+
+	data = irq_desc_get_irq_data(desc);
+
+	err = __irq_get_irqchip_state(data, which, state);
+
+	irq_put_desc_busunlock(desc, flags);
+	return err;
+}
+EXPORT_SYMBOL_GPL(irq_get_irqchip_state);
+
+/**
+ *	irq_set_irqchip_state - set the state of a forwarded interrupt.
+ *	@irq: Interrupt line that is forwarded to a VM
+ *	@which: State to be restored (one of IRQCHIP_STATE_*)
+ *	@val: Value corresponding to @which
+ *
+ *	This call sets the internal irqchip state of an interrupt,
+ *	depending on the value of @which.
+ *
+ *	This function should be called with migration disabled if the
+ *	interrupt controller has per-cpu registers.
+ */
+int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
+			  bool val)
+{
+	struct irq_desc *desc;
+	struct irq_data *data;
+	struct irq_chip *chip;
+	unsigned long flags;
+	int err = -EINVAL;
+
+	desc = irq_get_desc_buslock(irq, &flags, 0);
+	if (!desc)
+		return err;
+
+	data = irq_desc_get_irq_data(desc);
+
+	do {
+		chip = irq_data_get_irq_chip(data);
+		if (WARN_ON_ONCE(!chip)) {
+			err = -ENODEV;
+			goto out_unlock;
+		}
+		if (chip->irq_set_irqchip_state)
+			break;
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+		data = data->parent_data;
+#else
+		data = NULL;
+#endif
+	} while (data);
+
+	if (data)
+		err = chip->irq_set_irqchip_state(data, which, val);
+
+out_unlock:
+	irq_put_desc_busunlock(desc, flags);
+	return err;
+}
+EXPORT_SYMBOL_GPL(irq_set_irqchip_state);
+
+/**
+ * irq_has_action - Check whether an interrupt is requested
+ * @irq:	The linux irq number
+ *
+ * Returns: A snapshot of the current state
+ */
+bool irq_has_action(unsigned int irq)
+{
+	bool res;
+
+	rcu_read_lock();
+	res = irq_desc_has_action(irq_to_desc(irq));
+	rcu_read_unlock();
+	return res;
+}
+EXPORT_SYMBOL_GPL(irq_has_action);
+
+/**
+ * irq_check_status_bit - Check whether bits in the irq descriptor status are set
+ * @irq:	The linux irq number
+ * @bitmask:	The bitmask to evaluate
+ *
+ * Returns: True if one of the bits in @bitmask is set
+ */
+bool irq_check_status_bit(unsigned int irq, unsigned int bitmask)
+{
+	struct irq_desc *desc;
+	bool res = false;
+
+	rcu_read_lock();
+	desc = irq_to_desc(irq);
+	if (desc)
+		res = !!(desc->status_use_accessors & bitmask);
+	rcu_read_unlock();
+	return res;
+}
+EXPORT_SYMBOL_GPL(irq_check_status_bit);
diff --git a/kernel/irq/matrix.c b/kernel/irq/matrix.c
new file mode 100644
index 000000000..75d0ae490
--- /dev/null
+++ b/kernel/irq/matrix.c
@@ -0,0 +1,513 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2017 Thomas Gleixner <tglx@linutronix.de>
+
+#include <linux/spinlock.h>
+#include <linux/seq_file.h>
+#include <linux/bitmap.h>
+#include <linux/percpu.h>
+#include <linux/cpu.h>
+#include <linux/irq.h>
+
+#define IRQ_MATRIX_SIZE	(BITS_TO_LONGS(IRQ_MATRIX_BITS))
+
+struct cpumap {
+	unsigned int		available;
+	unsigned int		allocated;
+	unsigned int		managed;
+	unsigned int		managed_allocated;
+	bool			initialized;
+	bool			online;
+	unsigned long		alloc_map[IRQ_MATRIX_SIZE];
+	unsigned long		managed_map[IRQ_MATRIX_SIZE];
+};
+
+struct irq_matrix {
+	unsigned int		matrix_bits;
+	unsigned int		alloc_start;
+	unsigned int		alloc_end;
+	unsigned int		alloc_size;
+	unsigned int		global_available;
+	unsigned int		global_reserved;
+	unsigned int		systembits_inalloc;
+	unsigned int		total_allocated;
+	unsigned int		online_maps;
+	struct cpumap __percpu	*maps;
+	unsigned long		scratch_map[IRQ_MATRIX_SIZE];
+	unsigned long		system_map[IRQ_MATRIX_SIZE];
+};
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/irq_matrix.h>
+
+/**
+ * irq_alloc_matrix - Allocate a irq_matrix structure and initialize it
+ * @matrix_bits:	Number of matrix bits must be <= IRQ_MATRIX_BITS
+ * @alloc_start:	From which bit the allocation search starts
+ * @alloc_end:		At which bit the allocation search ends, i.e first
+ *			invalid bit
+ */
+__init struct irq_matrix *irq_alloc_matrix(unsigned int matrix_bits,
+					   unsigned int alloc_start,
+					   unsigned int alloc_end)
+{
+	struct irq_matrix *m;
+
+	if (matrix_bits > IRQ_MATRIX_BITS)
+		return NULL;
+
+	m = kzalloc(sizeof(*m), GFP_KERNEL);
+	if (!m)
+		return NULL;
+
+	m->matrix_bits = matrix_bits;
+	m->alloc_start = alloc_start;
+	m->alloc_end = alloc_end;
+	m->alloc_size = alloc_end - alloc_start;
+	m->maps = alloc_percpu(*m->maps);
+	if (!m->maps) {
+		kfree(m);
+		return NULL;
+	}
+	return m;
+}
+
+/**
+ * irq_matrix_online - Bring the local CPU matrix online
+ * @m:		Matrix pointer
+ */
+void irq_matrix_online(struct irq_matrix *m)
+{
+	struct cpumap *cm = this_cpu_ptr(m->maps);
+
+	BUG_ON(cm->online);
+
+	if (!cm->initialized) {
+		cm->available = m->alloc_size;
+		cm->available -= cm->managed + m->systembits_inalloc;
+		cm->initialized = true;
+	}
+	m->global_available += cm->available;
+	cm->online = true;
+	m->online_maps++;
+	trace_irq_matrix_online(m);
+}
+
+/**
+ * irq_matrix_offline - Bring the local CPU matrix offline
+ * @m:		Matrix pointer
+ */
+void irq_matrix_offline(struct irq_matrix *m)
+{
+	struct cpumap *cm = this_cpu_ptr(m->maps);
+
+	/* Update the global available size */
+	m->global_available -= cm->available;
+	cm->online = false;
+	m->online_maps--;
+	trace_irq_matrix_offline(m);
+}
+
+static unsigned int matrix_alloc_area(struct irq_matrix *m, struct cpumap *cm,
+				      unsigned int num, bool managed)
+{
+	unsigned int area, start = m->alloc_start;
+	unsigned int end = m->alloc_end;
+
+	bitmap_or(m->scratch_map, cm->managed_map, m->system_map, end);
+	bitmap_or(m->scratch_map, m->scratch_map, cm->alloc_map, end);
+	area = bitmap_find_next_zero_area(m->scratch_map, end, start, num, 0);
+	if (area >= end)
+		return area;
+	if (managed)
+		bitmap_set(cm->managed_map, area, num);
+	else
+		bitmap_set(cm->alloc_map, area, num);
+	return area;
+}
+
+/* Find the best CPU which has the lowest vector allocation count */
+static unsigned int matrix_find_best_cpu(struct irq_matrix *m,
+					const struct cpumask *msk)
+{
+	unsigned int cpu, best_cpu, maxavl = 0;
+	struct cpumap *cm;
+
+	best_cpu = UINT_MAX;
+
+	for_each_cpu(cpu, msk) {
+		cm = per_cpu_ptr(m->maps, cpu);
+
+		if (!cm->online || cm->available <= maxavl)
+			continue;
+
+		best_cpu = cpu;
+		maxavl = cm->available;
+	}
+	return best_cpu;
+}
+
+/* Find the best CPU which has the lowest number of managed IRQs allocated */
+static unsigned int matrix_find_best_cpu_managed(struct irq_matrix *m,
+						const struct cpumask *msk)
+{
+	unsigned int cpu, best_cpu, allocated = UINT_MAX;
+	struct cpumap *cm;
+
+	best_cpu = UINT_MAX;
+
+	for_each_cpu(cpu, msk) {
+		cm = per_cpu_ptr(m->maps, cpu);
+
+		if (!cm->online || cm->managed_allocated > allocated)
+			continue;
+
+		best_cpu = cpu;
+		allocated = cm->managed_allocated;
+	}
+	return best_cpu;
+}
+
+/**
+ * irq_matrix_assign_system - Assign system wide entry in the matrix
+ * @m:		Matrix pointer
+ * @bit:	Which bit to reserve
+ * @replace:	Replace an already allocated vector with a system
+ *		vector at the same bit position.
+ *
+ * The BUG_ON()s below are on purpose. If this goes wrong in the
+ * early boot process, then the chance to survive is about zero.
+ * If this happens when the system is life, it's not much better.
+ */
+void irq_matrix_assign_system(struct irq_matrix *m, unsigned int bit,
+			      bool replace)
+{
+	struct cpumap *cm = this_cpu_ptr(m->maps);
+
+	BUG_ON(bit > m->matrix_bits);
+	BUG_ON(m->online_maps > 1 || (m->online_maps && !replace));
+
+	set_bit(bit, m->system_map);
+	if (replace) {
+		BUG_ON(!test_and_clear_bit(bit, cm->alloc_map));
+		cm->allocated--;
+		m->total_allocated--;
+	}
+	if (bit >= m->alloc_start && bit < m->alloc_end)
+		m->systembits_inalloc++;
+
+	trace_irq_matrix_assign_system(bit, m);
+}
+
+/**
+ * irq_matrix_reserve_managed - Reserve a managed interrupt in a CPU map
+ * @m:		Matrix pointer
+ * @msk:	On which CPUs the bits should be reserved.
+ *
+ * Can be called for offline CPUs. Note, this will only reserve one bit
+ * on all CPUs in @msk, but it's not guaranteed that the bits are at the
+ * same offset on all CPUs
+ */
+int irq_matrix_reserve_managed(struct irq_matrix *m, const struct cpumask *msk)
+{
+	unsigned int cpu, failed_cpu;
+
+	for_each_cpu(cpu, msk) {
+		struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
+		unsigned int bit;
+
+		bit = matrix_alloc_area(m, cm, 1, true);
+		if (bit >= m->alloc_end)
+			goto cleanup;
+		cm->managed++;
+		if (cm->online) {
+			cm->available--;
+			m->global_available--;
+		}
+		trace_irq_matrix_reserve_managed(bit, cpu, m, cm);
+	}
+	return 0;
+cleanup:
+	failed_cpu = cpu;
+	for_each_cpu(cpu, msk) {
+		if (cpu == failed_cpu)
+			break;
+		irq_matrix_remove_managed(m, cpumask_of(cpu));
+	}
+	return -ENOSPC;
+}
+
+/**
+ * irq_matrix_remove_managed - Remove managed interrupts in a CPU map
+ * @m:		Matrix pointer
+ * @msk:	On which CPUs the bits should be removed
+ *
+ * Can be called for offline CPUs
+ *
+ * This removes not allocated managed interrupts from the map. It does
+ * not matter which one because the managed interrupts free their
+ * allocation when they shut down. If not, the accounting is screwed,
+ * but all what can be done at this point is warn about it.
+ */
+void irq_matrix_remove_managed(struct irq_matrix *m, const struct cpumask *msk)
+{
+	unsigned int cpu;
+
+	for_each_cpu(cpu, msk) {
+		struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
+		unsigned int bit, end = m->alloc_end;
+
+		if (WARN_ON_ONCE(!cm->managed))
+			continue;
+
+		/* Get managed bit which are not allocated */
+		bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end);
+
+		bit = find_first_bit(m->scratch_map, end);
+		if (WARN_ON_ONCE(bit >= end))
+			continue;
+
+		clear_bit(bit, cm->managed_map);
+
+		cm->managed--;
+		if (cm->online) {
+			cm->available++;
+			m->global_available++;
+		}
+		trace_irq_matrix_remove_managed(bit, cpu, m, cm);
+	}
+}
+
+/**
+ * irq_matrix_alloc_managed - Allocate a managed interrupt in a CPU map
+ * @m:		Matrix pointer
+ * @msk:	Which CPUs to search in
+ * @mapped_cpu:	Pointer to store the CPU for which the irq was allocated
+ */
+int irq_matrix_alloc_managed(struct irq_matrix *m, const struct cpumask *msk,
+			     unsigned int *mapped_cpu)
+{
+	unsigned int bit, cpu, end;
+	struct cpumap *cm;
+
+	if (cpumask_empty(msk))
+		return -EINVAL;
+
+	cpu = matrix_find_best_cpu_managed(m, msk);
+	if (cpu == UINT_MAX)
+		return -ENOSPC;
+
+	cm = per_cpu_ptr(m->maps, cpu);
+	end = m->alloc_end;
+	/* Get managed bit which are not allocated */
+	bitmap_andnot(m->scratch_map, cm->managed_map, cm->alloc_map, end);
+	bit = find_first_bit(m->scratch_map, end);
+	if (bit >= end)
+		return -ENOSPC;
+	set_bit(bit, cm->alloc_map);
+	cm->allocated++;
+	cm->managed_allocated++;
+	m->total_allocated++;
+	*mapped_cpu = cpu;
+	trace_irq_matrix_alloc_managed(bit, cpu, m, cm);
+	return bit;
+}
+
+/**
+ * irq_matrix_assign - Assign a preallocated interrupt in the local CPU map
+ * @m:		Matrix pointer
+ * @bit:	Which bit to mark
+ *
+ * This should only be used to mark preallocated vectors
+ */
+void irq_matrix_assign(struct irq_matrix *m, unsigned int bit)
+{
+	struct cpumap *cm = this_cpu_ptr(m->maps);
+
+	if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end))
+		return;
+	if (WARN_ON_ONCE(test_and_set_bit(bit, cm->alloc_map)))
+		return;
+	cm->allocated++;
+	m->total_allocated++;
+	cm->available--;
+	m->global_available--;
+	trace_irq_matrix_assign(bit, smp_processor_id(), m, cm);
+}
+
+/**
+ * irq_matrix_reserve - Reserve interrupts
+ * @m:		Matrix pointer
+ *
+ * This is merely a book keeping call. It increments the number of globally
+ * reserved interrupt bits w/o actually allocating them. This allows to
+ * setup interrupt descriptors w/o assigning low level resources to it.
+ * The actual allocation happens when the interrupt gets activated.
+ */
+void irq_matrix_reserve(struct irq_matrix *m)
+{
+	if (m->global_reserved == m->global_available)
+		pr_warn("Interrupt reservation exceeds available resources\n");
+
+	m->global_reserved++;
+	trace_irq_matrix_reserve(m);
+}
+
+/**
+ * irq_matrix_remove_reserved - Remove interrupt reservation
+ * @m:		Matrix pointer
+ *
+ * This is merely a book keeping call. It decrements the number of globally
+ * reserved interrupt bits. This is used to undo irq_matrix_reserve() when the
+ * interrupt was never in use and a real vector allocated, which undid the
+ * reservation.
+ */
+void irq_matrix_remove_reserved(struct irq_matrix *m)
+{
+	m->global_reserved--;
+	trace_irq_matrix_remove_reserved(m);
+}
+
+/**
+ * irq_matrix_alloc - Allocate a regular interrupt in a CPU map
+ * @m:		Matrix pointer
+ * @msk:	Which CPUs to search in
+ * @reserved:	Allocate previously reserved interrupts
+ * @mapped_cpu: Pointer to store the CPU for which the irq was allocated
+ */
+int irq_matrix_alloc(struct irq_matrix *m, const struct cpumask *msk,
+		     bool reserved, unsigned int *mapped_cpu)
+{
+	unsigned int cpu, bit;
+	struct cpumap *cm;
+
+	/*
+	 * Not required in theory, but matrix_find_best_cpu() uses
+	 * for_each_cpu() which ignores the cpumask on UP .
+	 */
+	if (cpumask_empty(msk))
+		return -EINVAL;
+
+	cpu = matrix_find_best_cpu(m, msk);
+	if (cpu == UINT_MAX)
+		return -ENOSPC;
+
+	cm = per_cpu_ptr(m->maps, cpu);
+	bit = matrix_alloc_area(m, cm, 1, false);
+	if (bit >= m->alloc_end)
+		return -ENOSPC;
+	cm->allocated++;
+	cm->available--;
+	m->total_allocated++;
+	m->global_available--;
+	if (reserved)
+		m->global_reserved--;
+	*mapped_cpu = cpu;
+	trace_irq_matrix_alloc(bit, cpu, m, cm);
+	return bit;
+
+}
+
+/**
+ * irq_matrix_free - Free allocated interrupt in the matrix
+ * @m:		Matrix pointer
+ * @cpu:	Which CPU map needs be updated
+ * @bit:	The bit to remove
+ * @managed:	If true, the interrupt is managed and not accounted
+ *		as available.
+ */
+void irq_matrix_free(struct irq_matrix *m, unsigned int cpu,
+		     unsigned int bit, bool managed)
+{
+	struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
+
+	if (WARN_ON_ONCE(bit < m->alloc_start || bit >= m->alloc_end))
+		return;
+
+	if (WARN_ON_ONCE(!test_and_clear_bit(bit, cm->alloc_map)))
+		return;
+
+	cm->allocated--;
+	if(managed)
+		cm->managed_allocated--;
+
+	if (cm->online)
+		m->total_allocated--;
+
+	if (!managed) {
+		cm->available++;
+		if (cm->online)
+			m->global_available++;
+	}
+	trace_irq_matrix_free(bit, cpu, m, cm);
+}
+
+/**
+ * irq_matrix_available - Get the number of globally available irqs
+ * @m:		Pointer to the matrix to query
+ * @cpudown:	If true, the local CPU is about to go down, adjust
+ *		the number of available irqs accordingly
+ */
+unsigned int irq_matrix_available(struct irq_matrix *m, bool cpudown)
+{
+	struct cpumap *cm = this_cpu_ptr(m->maps);
+
+	if (!cpudown)
+		return m->global_available;
+	return m->global_available - cm->available;
+}
+
+/**
+ * irq_matrix_reserved - Get the number of globally reserved irqs
+ * @m:		Pointer to the matrix to query
+ */
+unsigned int irq_matrix_reserved(struct irq_matrix *m)
+{
+	return m->global_reserved;
+}
+
+/**
+ * irq_matrix_allocated - Get the number of allocated non-managed irqs on the local CPU
+ * @m:		Pointer to the matrix to search
+ *
+ * This returns number of allocated non-managed interrupts.
+ */
+unsigned int irq_matrix_allocated(struct irq_matrix *m)
+{
+	struct cpumap *cm = this_cpu_ptr(m->maps);
+
+	return cm->allocated - cm->managed_allocated;
+}
+
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+/**
+ * irq_matrix_debug_show - Show detailed allocation information
+ * @sf:		Pointer to the seq_file to print to
+ * @m:		Pointer to the matrix allocator
+ * @ind:	Indentation for the print format
+ *
+ * Note, this is a lockless snapshot.
+ */
+void irq_matrix_debug_show(struct seq_file *sf, struct irq_matrix *m, int ind)
+{
+	unsigned int nsys = bitmap_weight(m->system_map, m->matrix_bits);
+	int cpu;
+
+	seq_printf(sf, "Online bitmaps:   %6u\n", m->online_maps);
+	seq_printf(sf, "Global available: %6u\n", m->global_available);
+	seq_printf(sf, "Global reserved:  %6u\n", m->global_reserved);
+	seq_printf(sf, "Total allocated:  %6u\n", m->total_allocated);
+	seq_printf(sf, "System: %u: %*pbl\n", nsys, m->matrix_bits,
+		   m->system_map);
+	seq_printf(sf, "%*s| CPU | avl | man | mac | act | vectors\n", ind, " ");
+	cpus_read_lock();
+	for_each_online_cpu(cpu) {
+		struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
+
+		seq_printf(sf, "%*s %4d  %4u  %4u  %4u %4u  %*pbl\n", ind, " ",
+			   cpu, cm->available, cm->managed,
+			   cm->managed_allocated, cm->allocated,
+			   m->matrix_bits, cm->alloc_map);
+	}
+	cpus_read_unlock();
+}
+#endif
diff --git a/kernel/irq/migration.c b/kernel/irq/migration.c
new file mode 100644
index 000000000..61ca924ef
--- /dev/null
+++ b/kernel/irq/migration.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+
+#include "internals.h"
+
+/**
+ * irq_fixup_move_pending - Cleanup irq move pending from a dying CPU
+ * @desc:		Interrupt descriptor to clean up
+ * @force_clear:	If set clear the move pending bit unconditionally.
+ *			If not set, clear it only when the dying CPU is the
+ *			last one in the pending mask.
+ *
+ * Returns true if the pending bit was set and the pending mask contains an
+ * online CPU other than the dying CPU.
+ */
+bool irq_fixup_move_pending(struct irq_desc *desc, bool force_clear)
+{
+	struct irq_data *data = irq_desc_get_irq_data(desc);
+
+	if (!irqd_is_setaffinity_pending(data))
+		return false;
+
+	/*
+	 * The outgoing CPU might be the last online target in a pending
+	 * interrupt move. If that's the case clear the pending move bit.
+	 */
+	if (cpumask_any_and(desc->pending_mask, cpu_online_mask) >= nr_cpu_ids) {
+		irqd_clr_move_pending(data);
+		return false;
+	}
+	if (force_clear)
+		irqd_clr_move_pending(data);
+	return true;
+}
+
+void irq_move_masked_irq(struct irq_data *idata)
+{
+	struct irq_desc *desc = irq_data_to_desc(idata);
+	struct irq_data *data = &desc->irq_data;
+	struct irq_chip *chip = data->chip;
+
+	if (likely(!irqd_is_setaffinity_pending(data)))
+		return;
+
+	irqd_clr_move_pending(data);
+
+	/*
+	 * Paranoia: cpu-local interrupts shouldn't be calling in here anyway.
+	 */
+	if (irqd_is_per_cpu(data)) {
+		WARN_ON(1);
+		return;
+	}
+
+	if (unlikely(cpumask_empty(desc->pending_mask)))
+		return;
+
+	if (!chip->irq_set_affinity)
+		return;
+
+	assert_raw_spin_locked(&desc->lock);
+
+	/*
+	 * If there was a valid mask to work with, please
+	 * do the disable, re-program, enable sequence.
+	 * This is *not* particularly important for level triggered
+	 * but in a edge trigger case, we might be setting rte
+	 * when an active trigger is coming in. This could
+	 * cause some ioapics to mal-function.
+	 * Being paranoid i guess!
+	 *
+	 * For correct operation this depends on the caller
+	 * masking the irqs.
+	 */
+	if (cpumask_any_and(desc->pending_mask, cpu_online_mask) < nr_cpu_ids) {
+		int ret;
+
+		ret = irq_do_set_affinity(data, desc->pending_mask, false);
+		/*
+		 * If the there is a cleanup pending in the underlying
+		 * vector management, reschedule the move for the next
+		 * interrupt. Leave desc->pending_mask intact.
+		 */
+		if (ret == -EBUSY) {
+			irqd_set_move_pending(data);
+			return;
+		}
+	}
+	cpumask_clear(desc->pending_mask);
+}
+
+void __irq_move_irq(struct irq_data *idata)
+{
+	bool masked;
+
+	/*
+	 * Get top level irq_data when CONFIG_IRQ_DOMAIN_HIERARCHY is enabled,
+	 * and it should be optimized away when CONFIG_IRQ_DOMAIN_HIERARCHY is
+	 * disabled. So we avoid an "#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY" here.
+	 */
+	idata = irq_desc_get_irq_data(irq_data_to_desc(idata));
+
+	if (unlikely(irqd_irq_disabled(idata)))
+		return;
+
+	/*
+	 * Be careful vs. already masked interrupts. If this is a
+	 * threaded interrupt with ONESHOT set, we can end up with an
+	 * interrupt storm.
+	 */
+	masked = irqd_irq_masked(idata);
+	if (!masked)
+		idata->chip->irq_mask(idata);
+	irq_move_masked_irq(idata);
+	if (!masked)
+		idata->chip->irq_unmask(idata);
+}
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
new file mode 100644
index 000000000..4e462b5f7
--- /dev/null
+++ b/kernel/irq/msi.c
@@ -0,0 +1,1042 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2014 Intel Corp.
+ * Author: Jiang Liu <jiang.liu@linux.intel.com>
+ *
+ * This file is licensed under GPLv2.
+ *
+ * This file contains common code to support Message Signaled Interrupts for
+ * PCI compatible and non PCI compatible devices.
+ */
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/msi.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/pci.h>
+
+#include "internals.h"
+
+static inline int msi_sysfs_create_group(struct device *dev);
+
+/**
+ * msi_alloc_desc - Allocate an initialized msi_desc
+ * @dev:	Pointer to the device for which this is allocated
+ * @nvec:	The number of vectors used in this entry
+ * @affinity:	Optional pointer to an affinity mask array size of @nvec
+ *
+ * If @affinity is not %NULL then an affinity array[@nvec] is allocated
+ * and the affinity masks and flags from @affinity are copied.
+ *
+ * Return: pointer to allocated &msi_desc on success or %NULL on failure
+ */
+static struct msi_desc *msi_alloc_desc(struct device *dev, int nvec,
+					const struct irq_affinity_desc *affinity)
+{
+	struct msi_desc *desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+
+	if (!desc)
+		return NULL;
+
+	desc->dev = dev;
+	desc->nvec_used = nvec;
+	if (affinity) {
+		desc->affinity = kmemdup(affinity, nvec * sizeof(*desc->affinity), GFP_KERNEL);
+		if (!desc->affinity) {
+			kfree(desc);
+			return NULL;
+		}
+	}
+	return desc;
+}
+
+static void msi_free_desc(struct msi_desc *desc)
+{
+	kfree(desc->affinity);
+	kfree(desc);
+}
+
+static int msi_insert_desc(struct msi_device_data *md, struct msi_desc *desc, unsigned int index)
+{
+	int ret;
+
+	desc->msi_index = index;
+	ret = xa_insert(&md->__store, index, desc, GFP_KERNEL);
+	if (ret)
+		msi_free_desc(desc);
+	return ret;
+}
+
+/**
+ * msi_add_msi_desc - Allocate and initialize a MSI descriptor
+ * @dev:	Pointer to the device for which the descriptor is allocated
+ * @init_desc:	Pointer to an MSI descriptor to initialize the new descriptor
+ *
+ * Return: 0 on success or an appropriate failure code.
+ */
+int msi_add_msi_desc(struct device *dev, struct msi_desc *init_desc)
+{
+	struct msi_desc *desc;
+
+	lockdep_assert_held(&dev->msi.data->mutex);
+
+	desc = msi_alloc_desc(dev, init_desc->nvec_used, init_desc->affinity);
+	if (!desc)
+		return -ENOMEM;
+
+	/* Copy type specific data to the new descriptor. */
+	desc->pci = init_desc->pci;
+	return msi_insert_desc(dev->msi.data, desc, init_desc->msi_index);
+}
+
+/**
+ * msi_add_simple_msi_descs - Allocate and initialize MSI descriptors
+ * @dev:	Pointer to the device for which the descriptors are allocated
+ * @index:	Index for the first MSI descriptor
+ * @ndesc:	Number of descriptors to allocate
+ *
+ * Return: 0 on success or an appropriate failure code.
+ */
+static int msi_add_simple_msi_descs(struct device *dev, unsigned int index, unsigned int ndesc)
+{
+	unsigned int idx, last = index + ndesc - 1;
+	struct msi_desc *desc;
+	int ret;
+
+	lockdep_assert_held(&dev->msi.data->mutex);
+
+	for (idx = index; idx <= last; idx++) {
+		desc = msi_alloc_desc(dev, 1, NULL);
+		if (!desc)
+			goto fail_mem;
+		ret = msi_insert_desc(dev->msi.data, desc, idx);
+		if (ret)
+			goto fail;
+	}
+	return 0;
+
+fail_mem:
+	ret = -ENOMEM;
+fail:
+	msi_free_msi_descs_range(dev, MSI_DESC_NOTASSOCIATED, index, last);
+	return ret;
+}
+
+static bool msi_desc_match(struct msi_desc *desc, enum msi_desc_filter filter)
+{
+	switch (filter) {
+	case MSI_DESC_ALL:
+		return true;
+	case MSI_DESC_NOTASSOCIATED:
+		return !desc->irq;
+	case MSI_DESC_ASSOCIATED:
+		return !!desc->irq;
+	}
+	WARN_ON_ONCE(1);
+	return false;
+}
+
+/**
+ * msi_free_msi_descs_range - Free MSI descriptors of a device
+ * @dev:		Device to free the descriptors
+ * @filter:		Descriptor state filter
+ * @first_index:	Index to start freeing from
+ * @last_index:		Last index to be freed
+ */
+void msi_free_msi_descs_range(struct device *dev, enum msi_desc_filter filter,
+			      unsigned int first_index, unsigned int last_index)
+{
+	struct xarray *xa = &dev->msi.data->__store;
+	struct msi_desc *desc;
+	unsigned long idx;
+
+	lockdep_assert_held(&dev->msi.data->mutex);
+
+	xa_for_each_range(xa, idx, desc, first_index, last_index) {
+		if (msi_desc_match(desc, filter)) {
+			xa_erase(xa, idx);
+			msi_free_desc(desc);
+		}
+	}
+}
+
+void __get_cached_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
+{
+	*msg = entry->msg;
+}
+
+void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg)
+{
+	struct msi_desc *entry = irq_get_msi_desc(irq);
+
+	__get_cached_msi_msg(entry, msg);
+}
+EXPORT_SYMBOL_GPL(get_cached_msi_msg);
+
+static void msi_device_data_release(struct device *dev, void *res)
+{
+	struct msi_device_data *md = res;
+
+	WARN_ON_ONCE(!xa_empty(&md->__store));
+	xa_destroy(&md->__store);
+	dev->msi.data = NULL;
+}
+
+/**
+ * msi_setup_device_data - Setup MSI device data
+ * @dev:	Device for which MSI device data should be set up
+ *
+ * Return: 0 on success, appropriate error code otherwise
+ *
+ * This can be called more than once for @dev. If the MSI device data is
+ * already allocated the call succeeds. The allocated memory is
+ * automatically released when the device is destroyed.
+ */
+int msi_setup_device_data(struct device *dev)
+{
+	struct msi_device_data *md;
+	int ret;
+
+	if (dev->msi.data)
+		return 0;
+
+	md = devres_alloc(msi_device_data_release, sizeof(*md), GFP_KERNEL);
+	if (!md)
+		return -ENOMEM;
+
+	ret = msi_sysfs_create_group(dev);
+	if (ret) {
+		devres_free(md);
+		return ret;
+	}
+
+	xa_init(&md->__store);
+	mutex_init(&md->mutex);
+	dev->msi.data = md;
+	devres_add(dev, md);
+	return 0;
+}
+
+/**
+ * msi_lock_descs - Lock the MSI descriptor storage of a device
+ * @dev:	Device to operate on
+ */
+void msi_lock_descs(struct device *dev)
+{
+	mutex_lock(&dev->msi.data->mutex);
+}
+EXPORT_SYMBOL_GPL(msi_lock_descs);
+
+/**
+ * msi_unlock_descs - Unlock the MSI descriptor storage of a device
+ * @dev:	Device to operate on
+ */
+void msi_unlock_descs(struct device *dev)
+{
+	/* Invalidate the index wich was cached by the iterator */
+	dev->msi.data->__iter_idx = MSI_MAX_INDEX;
+	mutex_unlock(&dev->msi.data->mutex);
+}
+EXPORT_SYMBOL_GPL(msi_unlock_descs);
+
+static struct msi_desc *msi_find_desc(struct msi_device_data *md, enum msi_desc_filter filter)
+{
+	struct msi_desc *desc;
+
+	xa_for_each_start(&md->__store, md->__iter_idx, desc, md->__iter_idx) {
+		if (msi_desc_match(desc, filter))
+			return desc;
+	}
+	md->__iter_idx = MSI_MAX_INDEX;
+	return NULL;
+}
+
+/**
+ * msi_first_desc - Get the first MSI descriptor of a device
+ * @dev:	Device to operate on
+ * @filter:	Descriptor state filter
+ *
+ * Must be called with the MSI descriptor mutex held, i.e. msi_lock_descs()
+ * must be invoked before the call.
+ *
+ * Return: Pointer to the first MSI descriptor matching the search
+ *	   criteria, NULL if none found.
+ */
+struct msi_desc *msi_first_desc(struct device *dev, enum msi_desc_filter filter)
+{
+	struct msi_device_data *md = dev->msi.data;
+
+	if (WARN_ON_ONCE(!md))
+		return NULL;
+
+	lockdep_assert_held(&md->mutex);
+
+	md->__iter_idx = 0;
+	return msi_find_desc(md, filter);
+}
+EXPORT_SYMBOL_GPL(msi_first_desc);
+
+/**
+ * msi_next_desc - Get the next MSI descriptor of a device
+ * @dev:	Device to operate on
+ *
+ * The first invocation of msi_next_desc() has to be preceeded by a
+ * successful invocation of __msi_first_desc(). Consecutive invocations are
+ * only valid if the previous one was successful. All these operations have
+ * to be done within the same MSI mutex held region.
+ *
+ * Return: Pointer to the next MSI descriptor matching the search
+ *	   criteria, NULL if none found.
+ */
+struct msi_desc *msi_next_desc(struct device *dev, enum msi_desc_filter filter)
+{
+	struct msi_device_data *md = dev->msi.data;
+
+	if (WARN_ON_ONCE(!md))
+		return NULL;
+
+	lockdep_assert_held(&md->mutex);
+
+	if (md->__iter_idx >= (unsigned long)MSI_MAX_INDEX)
+		return NULL;
+
+	md->__iter_idx++;
+	return msi_find_desc(md, filter);
+}
+EXPORT_SYMBOL_GPL(msi_next_desc);
+
+/**
+ * msi_get_virq - Return Linux interrupt number of a MSI interrupt
+ * @dev:	Device to operate on
+ * @index:	MSI interrupt index to look for (0-based)
+ *
+ * Return: The Linux interrupt number on success (> 0), 0 if not found
+ */
+unsigned int msi_get_virq(struct device *dev, unsigned int index)
+{
+	struct msi_desc *desc;
+	unsigned int ret = 0;
+	bool pcimsi;
+
+	if (!dev->msi.data)
+		return 0;
+
+	pcimsi = dev_is_pci(dev) ? to_pci_dev(dev)->msi_enabled : false;
+
+	msi_lock_descs(dev);
+	desc = xa_load(&dev->msi.data->__store, pcimsi ? 0 : index);
+	if (desc && desc->irq) {
+		/*
+		 * PCI-MSI has only one descriptor for multiple interrupts.
+		 * PCI-MSIX and platform MSI use a descriptor per
+		 * interrupt.
+		 */
+		if (pcimsi) {
+			if (index < desc->nvec_used)
+				ret = desc->irq + index;
+		} else {
+			ret = desc->irq;
+		}
+	}
+	msi_unlock_descs(dev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(msi_get_virq);
+
+#ifdef CONFIG_SYSFS
+static struct attribute *msi_dev_attrs[] = {
+	NULL
+};
+
+static const struct attribute_group msi_irqs_group = {
+	.name	= "msi_irqs",
+	.attrs	= msi_dev_attrs,
+};
+
+static inline int msi_sysfs_create_group(struct device *dev)
+{
+	return devm_device_add_group(dev, &msi_irqs_group);
+}
+
+static ssize_t msi_mode_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	/* MSI vs. MSIX is per device not per interrupt */
+	bool is_msix = dev_is_pci(dev) ? to_pci_dev(dev)->msix_enabled : false;
+
+	return sysfs_emit(buf, "%s\n", is_msix ? "msix" : "msi");
+}
+
+static void msi_sysfs_remove_desc(struct device *dev, struct msi_desc *desc)
+{
+	struct device_attribute *attrs = desc->sysfs_attrs;
+	int i;
+
+	if (!attrs)
+		return;
+
+	desc->sysfs_attrs = NULL;
+	for (i = 0; i < desc->nvec_used; i++) {
+		if (attrs[i].show)
+			sysfs_remove_file_from_group(&dev->kobj, &attrs[i].attr, msi_irqs_group.name);
+		kfree(attrs[i].attr.name);
+	}
+	kfree(attrs);
+}
+
+static int msi_sysfs_populate_desc(struct device *dev, struct msi_desc *desc)
+{
+	struct device_attribute *attrs;
+	int ret, i;
+
+	attrs = kcalloc(desc->nvec_used, sizeof(*attrs), GFP_KERNEL);
+	if (!attrs)
+		return -ENOMEM;
+
+	desc->sysfs_attrs = attrs;
+	for (i = 0; i < desc->nvec_used; i++) {
+		sysfs_attr_init(&attrs[i].attr);
+		attrs[i].attr.name = kasprintf(GFP_KERNEL, "%d", desc->irq + i);
+		if (!attrs[i].attr.name) {
+			ret = -ENOMEM;
+			goto fail;
+		}
+
+		attrs[i].attr.mode = 0444;
+		attrs[i].show = msi_mode_show;
+
+		ret = sysfs_add_file_to_group(&dev->kobj, &attrs[i].attr, msi_irqs_group.name);
+		if (ret) {
+			attrs[i].show = NULL;
+			goto fail;
+		}
+	}
+	return 0;
+
+fail:
+	msi_sysfs_remove_desc(dev, desc);
+	return ret;
+}
+
+#if defined(CONFIG_PCI_MSI_ARCH_FALLBACKS) || defined(CONFIG_PCI_XEN)
+/**
+ * msi_device_populate_sysfs - Populate msi_irqs sysfs entries for a device
+ * @dev:	The device (PCI, platform etc) which will get sysfs entries
+ */
+int msi_device_populate_sysfs(struct device *dev)
+{
+	struct msi_desc *desc;
+	int ret;
+
+	msi_for_each_desc(desc, dev, MSI_DESC_ASSOCIATED) {
+		if (desc->sysfs_attrs)
+			continue;
+		ret = msi_sysfs_populate_desc(dev, desc);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+/**
+ * msi_device_destroy_sysfs - Destroy msi_irqs sysfs entries for a device
+ * @dev:		The device (PCI, platform etc) for which to remove
+ *			sysfs entries
+ */
+void msi_device_destroy_sysfs(struct device *dev)
+{
+	struct msi_desc *desc;
+
+	msi_for_each_desc(desc, dev, MSI_DESC_ALL)
+		msi_sysfs_remove_desc(dev, desc);
+}
+#endif /* CONFIG_PCI_MSI_ARCH_FALLBACK || CONFIG_PCI_XEN */
+#else /* CONFIG_SYSFS */
+static inline int msi_sysfs_create_group(struct device *dev) { return 0; }
+static inline int msi_sysfs_populate_desc(struct device *dev, struct msi_desc *desc) { return 0; }
+static inline void msi_sysfs_remove_desc(struct device *dev, struct msi_desc *desc) { }
+#endif /* !CONFIG_SYSFS */
+
+#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
+static inline void irq_chip_write_msi_msg(struct irq_data *data,
+					  struct msi_msg *msg)
+{
+	data->chip->irq_write_msi_msg(data, msg);
+}
+
+static void msi_check_level(struct irq_domain *domain, struct msi_msg *msg)
+{
+	struct msi_domain_info *info = domain->host_data;
+
+	/*
+	 * If the MSI provider has messed with the second message and
+	 * not advertized that it is level-capable, signal the breakage.
+	 */
+	WARN_ON(!((info->flags & MSI_FLAG_LEVEL_CAPABLE) &&
+		  (info->chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI)) &&
+		(msg[1].address_lo || msg[1].address_hi || msg[1].data));
+}
+
+/**
+ * msi_domain_set_affinity - Generic affinity setter function for MSI domains
+ * @irq_data:	The irq data associated to the interrupt
+ * @mask:	The affinity mask to set
+ * @force:	Flag to enforce setting (disable online checks)
+ *
+ * Intended to be used by MSI interrupt controllers which are
+ * implemented with hierarchical domains.
+ *
+ * Return: IRQ_SET_MASK_* result code
+ */
+int msi_domain_set_affinity(struct irq_data *irq_data,
+			    const struct cpumask *mask, bool force)
+{
+	struct irq_data *parent = irq_data->parent_data;
+	struct msi_msg msg[2] = { [1] = { }, };
+	int ret;
+
+	ret = parent->chip->irq_set_affinity(parent, mask, force);
+	if (ret >= 0 && ret != IRQ_SET_MASK_OK_DONE) {
+		BUG_ON(irq_chip_compose_msi_msg(irq_data, msg));
+		msi_check_level(irq_data->domain, msg);
+		irq_chip_write_msi_msg(irq_data, msg);
+	}
+
+	return ret;
+}
+
+static int msi_domain_activate(struct irq_domain *domain,
+			       struct irq_data *irq_data, bool early)
+{
+	struct msi_msg msg[2] = { [1] = { }, };
+
+	BUG_ON(irq_chip_compose_msi_msg(irq_data, msg));
+	msi_check_level(irq_data->domain, msg);
+	irq_chip_write_msi_msg(irq_data, msg);
+	return 0;
+}
+
+static void msi_domain_deactivate(struct irq_domain *domain,
+				  struct irq_data *irq_data)
+{
+	struct msi_msg msg[2];
+
+	memset(msg, 0, sizeof(msg));
+	irq_chip_write_msi_msg(irq_data, msg);
+}
+
+static int msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
+			    unsigned int nr_irqs, void *arg)
+{
+	struct msi_domain_info *info = domain->host_data;
+	struct msi_domain_ops *ops = info->ops;
+	irq_hw_number_t hwirq = ops->get_hwirq(info, arg);
+	int i, ret;
+
+	if (irq_find_mapping(domain, hwirq) > 0)
+		return -EEXIST;
+
+	if (domain->parent) {
+		ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
+		if (ret < 0)
+			return ret;
+	}
+
+	for (i = 0; i < nr_irqs; i++) {
+		ret = ops->msi_init(domain, info, virq + i, hwirq + i, arg);
+		if (ret < 0) {
+			if (ops->msi_free) {
+				for (i--; i > 0; i--)
+					ops->msi_free(domain, info, virq + i);
+			}
+			irq_domain_free_irqs_top(domain, virq, nr_irqs);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static void msi_domain_free(struct irq_domain *domain, unsigned int virq,
+			    unsigned int nr_irqs)
+{
+	struct msi_domain_info *info = domain->host_data;
+	int i;
+
+	if (info->ops->msi_free) {
+		for (i = 0; i < nr_irqs; i++)
+			info->ops->msi_free(domain, info, virq + i);
+	}
+	irq_domain_free_irqs_top(domain, virq, nr_irqs);
+}
+
+static const struct irq_domain_ops msi_domain_ops = {
+	.alloc		= msi_domain_alloc,
+	.free		= msi_domain_free,
+	.activate	= msi_domain_activate,
+	.deactivate	= msi_domain_deactivate,
+};
+
+static irq_hw_number_t msi_domain_ops_get_hwirq(struct msi_domain_info *info,
+						msi_alloc_info_t *arg)
+{
+	return arg->hwirq;
+}
+
+static int msi_domain_ops_prepare(struct irq_domain *domain, struct device *dev,
+				  int nvec, msi_alloc_info_t *arg)
+{
+	memset(arg, 0, sizeof(*arg));
+	return 0;
+}
+
+static void msi_domain_ops_set_desc(msi_alloc_info_t *arg,
+				    struct msi_desc *desc)
+{
+	arg->desc = desc;
+}
+
+static int msi_domain_ops_init(struct irq_domain *domain,
+			       struct msi_domain_info *info,
+			       unsigned int virq, irq_hw_number_t hwirq,
+			       msi_alloc_info_t *arg)
+{
+	irq_domain_set_hwirq_and_chip(domain, virq, hwirq, info->chip,
+				      info->chip_data);
+	if (info->handler && info->handler_name) {
+		__irq_set_handler(virq, info->handler, 0, info->handler_name);
+		if (info->handler_data)
+			irq_set_handler_data(virq, info->handler_data);
+	}
+	return 0;
+}
+
+static int msi_domain_ops_check(struct irq_domain *domain,
+				struct msi_domain_info *info,
+				struct device *dev)
+{
+	return 0;
+}
+
+static struct msi_domain_ops msi_domain_ops_default = {
+	.get_hwirq		= msi_domain_ops_get_hwirq,
+	.msi_init		= msi_domain_ops_init,
+	.msi_check		= msi_domain_ops_check,
+	.msi_prepare		= msi_domain_ops_prepare,
+	.set_desc		= msi_domain_ops_set_desc,
+	.domain_alloc_irqs	= __msi_domain_alloc_irqs,
+	.domain_free_irqs	= __msi_domain_free_irqs,
+};
+
+static void msi_domain_update_dom_ops(struct msi_domain_info *info)
+{
+	struct msi_domain_ops *ops = info->ops;
+
+	if (ops == NULL) {
+		info->ops = &msi_domain_ops_default;
+		return;
+	}
+
+	if (ops->domain_alloc_irqs == NULL)
+		ops->domain_alloc_irqs = msi_domain_ops_default.domain_alloc_irqs;
+	if (ops->domain_free_irqs == NULL)
+		ops->domain_free_irqs = msi_domain_ops_default.domain_free_irqs;
+
+	if (!(info->flags & MSI_FLAG_USE_DEF_DOM_OPS))
+		return;
+
+	if (ops->get_hwirq == NULL)
+		ops->get_hwirq = msi_domain_ops_default.get_hwirq;
+	if (ops->msi_init == NULL)
+		ops->msi_init = msi_domain_ops_default.msi_init;
+	if (ops->msi_check == NULL)
+		ops->msi_check = msi_domain_ops_default.msi_check;
+	if (ops->msi_prepare == NULL)
+		ops->msi_prepare = msi_domain_ops_default.msi_prepare;
+	if (ops->set_desc == NULL)
+		ops->set_desc = msi_domain_ops_default.set_desc;
+}
+
+static void msi_domain_update_chip_ops(struct msi_domain_info *info)
+{
+	struct irq_chip *chip = info->chip;
+
+	BUG_ON(!chip || !chip->irq_mask || !chip->irq_unmask);
+	if (!chip->irq_set_affinity)
+		chip->irq_set_affinity = msi_domain_set_affinity;
+}
+
+/**
+ * msi_create_irq_domain - Create an MSI interrupt domain
+ * @fwnode:	Optional fwnode of the interrupt controller
+ * @info:	MSI domain info
+ * @parent:	Parent irq domain
+ *
+ * Return: pointer to the created &struct irq_domain or %NULL on failure
+ */
+struct irq_domain *msi_create_irq_domain(struct fwnode_handle *fwnode,
+					 struct msi_domain_info *info,
+					 struct irq_domain *parent)
+{
+	struct irq_domain *domain;
+
+	msi_domain_update_dom_ops(info);
+	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
+		msi_domain_update_chip_ops(info);
+
+	domain = irq_domain_create_hierarchy(parent, IRQ_DOMAIN_FLAG_MSI, 0,
+					     fwnode, &msi_domain_ops, info);
+
+	if (domain && !domain->name && info->chip)
+		domain->name = info->chip->name;
+
+	return domain;
+}
+
+int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
+			    int nvec, msi_alloc_info_t *arg)
+{
+	struct msi_domain_info *info = domain->host_data;
+	struct msi_domain_ops *ops = info->ops;
+	int ret;
+
+	ret = ops->msi_check(domain, info, dev);
+	if (ret == 0)
+		ret = ops->msi_prepare(domain, dev, nvec, arg);
+
+	return ret;
+}
+
+int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
+			     int virq_base, int nvec, msi_alloc_info_t *arg)
+{
+	struct msi_domain_info *info = domain->host_data;
+	struct msi_domain_ops *ops = info->ops;
+	struct msi_desc *desc;
+	int ret, virq;
+
+	msi_lock_descs(dev);
+	ret = msi_add_simple_msi_descs(dev, virq_base, nvec);
+	if (ret)
+		goto unlock;
+
+	for (virq = virq_base; virq < virq_base + nvec; virq++) {
+		desc = xa_load(&dev->msi.data->__store, virq);
+		desc->irq = virq;
+
+		ops->set_desc(arg, desc);
+		ret = irq_domain_alloc_irqs_hierarchy(domain, virq, 1, arg);
+		if (ret)
+			goto fail;
+
+		irq_set_msi_desc(virq, desc);
+	}
+	msi_unlock_descs(dev);
+	return 0;
+
+fail:
+	for (--virq; virq >= virq_base; virq--)
+		irq_domain_free_irqs_common(domain, virq, 1);
+	msi_free_msi_descs_range(dev, MSI_DESC_ALL, virq_base, virq_base + nvec - 1);
+unlock:
+	msi_unlock_descs(dev);
+	return ret;
+}
+
+/*
+ * Carefully check whether the device can use reservation mode. If
+ * reservation mode is enabled then the early activation will assign a
+ * dummy vector to the device. If the PCI/MSI device does not support
+ * masking of the entry then this can result in spurious interrupts when
+ * the device driver is not absolutely careful. But even then a malfunction
+ * of the hardware could result in a spurious interrupt on the dummy vector
+ * and render the device unusable. If the entry can be masked then the core
+ * logic will prevent the spurious interrupt and reservation mode can be
+ * used. For now reservation mode is restricted to PCI/MSI.
+ */
+static bool msi_check_reservation_mode(struct irq_domain *domain,
+				       struct msi_domain_info *info,
+				       struct device *dev)
+{
+	struct msi_desc *desc;
+
+	switch(domain->bus_token) {
+	case DOMAIN_BUS_PCI_MSI:
+	case DOMAIN_BUS_VMD_MSI:
+		break;
+	default:
+		return false;
+	}
+
+	if (!(info->flags & MSI_FLAG_MUST_REACTIVATE))
+		return false;
+
+	if (IS_ENABLED(CONFIG_PCI_MSI) && pci_msi_ignore_mask)
+		return false;
+
+	/*
+	 * Checking the first MSI descriptor is sufficient. MSIX supports
+	 * masking and MSI does so when the can_mask attribute is set.
+	 */
+	desc = msi_first_desc(dev, MSI_DESC_ALL);
+	return desc->pci.msi_attrib.is_msix || desc->pci.msi_attrib.can_mask;
+}
+
+static int msi_handle_pci_fail(struct irq_domain *domain, struct msi_desc *desc,
+			       int allocated)
+{
+	switch(domain->bus_token) {
+	case DOMAIN_BUS_PCI_MSI:
+	case DOMAIN_BUS_VMD_MSI:
+		if (IS_ENABLED(CONFIG_PCI_MSI))
+			break;
+		fallthrough;
+	default:
+		return -ENOSPC;
+	}
+
+	/* Let a failed PCI multi MSI allocation retry */
+	if (desc->nvec_used > 1)
+		return 1;
+
+	/* If there was a successful allocation let the caller know */
+	return allocated ? allocated : -ENOSPC;
+}
+
+#define VIRQ_CAN_RESERVE	0x01
+#define VIRQ_ACTIVATE		0x02
+
+static int msi_init_virq(struct irq_domain *domain, int virq, unsigned int vflags)
+{
+	struct irq_data *irqd = irq_domain_get_irq_data(domain, virq);
+	int ret;
+
+	if (!(vflags & VIRQ_CAN_RESERVE)) {
+		irqd_clr_can_reserve(irqd);
+
+		/*
+		 * If the interrupt is managed but no CPU is available to
+		 * service it, shut it down until better times. Note that
+		 * we only do this on the !RESERVE path as x86 (the only
+		 * architecture using this flag) deals with this in a
+		 * different way by using a catch-all vector.
+		 */
+		if ((vflags & VIRQ_ACTIVATE) &&
+		    irqd_affinity_is_managed(irqd) &&
+		    !cpumask_intersects(irq_data_get_affinity_mask(irqd),
+					cpu_online_mask)) {
+			    irqd_set_managed_shutdown(irqd);
+			    return 0;
+		    }
+	}
+
+	if (!(vflags & VIRQ_ACTIVATE))
+		return 0;
+
+	ret = irq_domain_activate_irq(irqd, vflags & VIRQ_CAN_RESERVE);
+	if (ret)
+		return ret;
+	/*
+	 * If the interrupt uses reservation mode, clear the activated bit
+	 * so request_irq() will assign the final vector.
+	 */
+	if (vflags & VIRQ_CAN_RESERVE)
+		irqd_clr_activated(irqd);
+	return 0;
+}
+
+int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
+			    int nvec)
+{
+	struct msi_domain_info *info = domain->host_data;
+	struct msi_domain_ops *ops = info->ops;
+	msi_alloc_info_t arg = { };
+	unsigned int vflags = 0;
+	struct msi_desc *desc;
+	int allocated = 0;
+	int i, ret, virq;
+
+	ret = msi_domain_prepare_irqs(domain, dev, nvec, &arg);
+	if (ret)
+		return ret;
+
+	/*
+	 * This flag is set by the PCI layer as we need to activate
+	 * the MSI entries before the PCI layer enables MSI in the
+	 * card. Otherwise the card latches a random msi message.
+	 */
+	if (info->flags & MSI_FLAG_ACTIVATE_EARLY)
+		vflags |= VIRQ_ACTIVATE;
+
+	/*
+	 * Interrupt can use a reserved vector and will not occupy
+	 * a real device vector until the interrupt is requested.
+	 */
+	if (msi_check_reservation_mode(domain, info, dev))
+		vflags |= VIRQ_CAN_RESERVE;
+
+	msi_for_each_desc(desc, dev, MSI_DESC_NOTASSOCIATED) {
+		ops->set_desc(&arg, desc);
+
+		virq = __irq_domain_alloc_irqs(domain, -1, desc->nvec_used,
+					       dev_to_node(dev), &arg, false,
+					       desc->affinity);
+		if (virq < 0)
+			return msi_handle_pci_fail(domain, desc, allocated);
+
+		for (i = 0; i < desc->nvec_used; i++) {
+			irq_set_msi_desc_off(virq, i, desc);
+			irq_debugfs_copy_devname(virq + i, dev);
+			ret = msi_init_virq(domain, virq + i, vflags);
+			if (ret)
+				return ret;
+		}
+		if (info->flags & MSI_FLAG_DEV_SYSFS) {
+			ret = msi_sysfs_populate_desc(dev, desc);
+			if (ret)
+				return ret;
+		}
+		allocated++;
+	}
+	return 0;
+}
+
+static int msi_domain_add_simple_msi_descs(struct msi_domain_info *info,
+					   struct device *dev,
+					   unsigned int num_descs)
+{
+	if (!(info->flags & MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS))
+		return 0;
+
+	return msi_add_simple_msi_descs(dev, 0, num_descs);
+}
+
+/**
+ * msi_domain_alloc_irqs_descs_locked - Allocate interrupts from a MSI interrupt domain
+ * @domain:	The domain to allocate from
+ * @dev:	Pointer to device struct of the device for which the interrupts
+ *		are allocated
+ * @nvec:	The number of interrupts to allocate
+ *
+ * Must be invoked from within a msi_lock_descs() / msi_unlock_descs()
+ * pair. Use this for MSI irqdomains which implement their own vector
+ * allocation/free.
+ *
+ * Return: %0 on success or an error code.
+ */
+int msi_domain_alloc_irqs_descs_locked(struct irq_domain *domain, struct device *dev,
+				       int nvec)
+{
+	struct msi_domain_info *info = domain->host_data;
+	struct msi_domain_ops *ops = info->ops;
+	int ret;
+
+	lockdep_assert_held(&dev->msi.data->mutex);
+
+	ret = msi_domain_add_simple_msi_descs(info, dev, nvec);
+	if (ret)
+		return ret;
+
+	ret = ops->domain_alloc_irqs(domain, dev, nvec);
+	if (ret)
+		msi_domain_free_irqs_descs_locked(domain, dev);
+	return ret;
+}
+
+/**
+ * msi_domain_alloc_irqs - Allocate interrupts from a MSI interrupt domain
+ * @domain:	The domain to allocate from
+ * @dev:	Pointer to device struct of the device for which the interrupts
+ *		are allocated
+ * @nvec:	The number of interrupts to allocate
+ *
+ * Return: %0 on success or an error code.
+ */
+int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev, int nvec)
+{
+	int ret;
+
+	msi_lock_descs(dev);
+	ret = msi_domain_alloc_irqs_descs_locked(domain, dev, nvec);
+	msi_unlock_descs(dev);
+	return ret;
+}
+
+void __msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
+{
+	struct msi_domain_info *info = domain->host_data;
+	struct irq_data *irqd;
+	struct msi_desc *desc;
+	int i;
+
+	/* Only handle MSI entries which have an interrupt associated */
+	msi_for_each_desc(desc, dev, MSI_DESC_ASSOCIATED) {
+		/* Make sure all interrupts are deactivated */
+		for (i = 0; i < desc->nvec_used; i++) {
+			irqd = irq_domain_get_irq_data(domain, desc->irq + i);
+			if (irqd && irqd_is_activated(irqd))
+				irq_domain_deactivate_irq(irqd);
+		}
+
+		irq_domain_free_irqs(desc->irq, desc->nvec_used);
+		if (info->flags & MSI_FLAG_DEV_SYSFS)
+			msi_sysfs_remove_desc(dev, desc);
+		desc->irq = 0;
+	}
+}
+
+static void msi_domain_free_msi_descs(struct msi_domain_info *info,
+				      struct device *dev)
+{
+	if (info->flags & MSI_FLAG_FREE_MSI_DESCS)
+		msi_free_msi_descs(dev);
+}
+
+/**
+ * msi_domain_free_irqs_descs_locked - Free interrupts from a MSI interrupt @domain associated to @dev
+ * @domain:	The domain to managing the interrupts
+ * @dev:	Pointer to device struct of the device for which the interrupts
+ *		are free
+ *
+ * Must be invoked from within a msi_lock_descs() / msi_unlock_descs()
+ * pair. Use this for MSI irqdomains which implement their own vector
+ * allocation.
+ */
+void msi_domain_free_irqs_descs_locked(struct irq_domain *domain, struct device *dev)
+{
+	struct msi_domain_info *info = domain->host_data;
+	struct msi_domain_ops *ops = info->ops;
+
+	lockdep_assert_held(&dev->msi.data->mutex);
+
+	ops->domain_free_irqs(domain, dev);
+	msi_domain_free_msi_descs(info, dev);
+}
+
+/**
+ * msi_domain_free_irqs - Free interrupts from a MSI interrupt @domain associated to @dev
+ * @domain:	The domain to managing the interrupts
+ * @dev:	Pointer to device struct of the device for which the interrupts
+ *		are free
+ */
+void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
+{
+	msi_lock_descs(dev);
+	msi_domain_free_irqs_descs_locked(domain, dev);
+	msi_unlock_descs(dev);
+}
+
+/**
+ * msi_get_domain_info - Get the MSI interrupt domain info for @domain
+ * @domain:	The interrupt domain to retrieve data from
+ *
+ * Return: the pointer to the msi_domain_info stored in @domain->host_data.
+ */
+struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain)
+{
+	return (struct msi_domain_info *)domain->host_data;
+}
+
+#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c
new file mode 100644
index 000000000..c556bc49d
--- /dev/null
+++ b/kernel/irq/pm.c
@@ -0,0 +1,260 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
+ *
+ * This file contains power management functions related to interrupts.
+ */
+
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/suspend.h>
+#include <linux/syscore_ops.h>
+
+#include "internals.h"
+
+bool irq_pm_check_wakeup(struct irq_desc *desc)
+{
+	if (irqd_is_wakeup_armed(&desc->irq_data)) {
+		irqd_clear(&desc->irq_data, IRQD_WAKEUP_ARMED);
+		desc->istate |= IRQS_SUSPENDED | IRQS_PENDING;
+		desc->depth++;
+		irq_disable(desc);
+		pm_system_irq_wakeup(irq_desc_get_irq(desc));
+		return true;
+	}
+	return false;
+}
+
+/*
+ * Called from __setup_irq() with desc->lock held after @action has
+ * been installed in the action chain.
+ */
+void irq_pm_install_action(struct irq_desc *desc, struct irqaction *action)
+{
+	desc->nr_actions++;
+
+	if (action->flags & IRQF_FORCE_RESUME)
+		desc->force_resume_depth++;
+
+	WARN_ON_ONCE(desc->force_resume_depth &&
+		     desc->force_resume_depth != desc->nr_actions);
+
+	if (action->flags & IRQF_NO_SUSPEND)
+		desc->no_suspend_depth++;
+	else if (action->flags & IRQF_COND_SUSPEND)
+		desc->cond_suspend_depth++;
+
+	WARN_ON_ONCE(desc->no_suspend_depth &&
+		     (desc->no_suspend_depth +
+			desc->cond_suspend_depth) != desc->nr_actions);
+}
+
+/*
+ * Called from __free_irq() with desc->lock held after @action has
+ * been removed from the action chain.
+ */
+void irq_pm_remove_action(struct irq_desc *desc, struct irqaction *action)
+{
+	desc->nr_actions--;
+
+	if (action->flags & IRQF_FORCE_RESUME)
+		desc->force_resume_depth--;
+
+	if (action->flags & IRQF_NO_SUSPEND)
+		desc->no_suspend_depth--;
+	else if (action->flags & IRQF_COND_SUSPEND)
+		desc->cond_suspend_depth--;
+}
+
+static bool suspend_device_irq(struct irq_desc *desc)
+{
+	unsigned long chipflags = irq_desc_get_chip(desc)->flags;
+	struct irq_data *irqd = &desc->irq_data;
+
+	if (!desc->action || irq_desc_is_chained(desc) ||
+	    desc->no_suspend_depth)
+		return false;
+
+	if (irqd_is_wakeup_set(irqd)) {
+		irqd_set(irqd, IRQD_WAKEUP_ARMED);
+
+		if ((chipflags & IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND) &&
+		     irqd_irq_disabled(irqd)) {
+			/*
+			 * Interrupt marked for wakeup is in disabled state.
+			 * Enable interrupt here to unmask/enable in irqchip
+			 * to be able to resume with such interrupts.
+			 */
+			__enable_irq(desc);
+			irqd_set(irqd, IRQD_IRQ_ENABLED_ON_SUSPEND);
+		}
+		/*
+		 * We return true here to force the caller to issue
+		 * synchronize_irq(). We need to make sure that the
+		 * IRQD_WAKEUP_ARMED is visible before we return from
+		 * suspend_device_irqs().
+		 */
+		return true;
+	}
+
+	desc->istate |= IRQS_SUSPENDED;
+	__disable_irq(desc);
+
+	/*
+	 * Hardware which has no wakeup source configuration facility
+	 * requires that the non wakeup interrupts are masked at the
+	 * chip level. The chip implementation indicates that with
+	 * IRQCHIP_MASK_ON_SUSPEND.
+	 */
+	if (chipflags & IRQCHIP_MASK_ON_SUSPEND)
+		mask_irq(desc);
+	return true;
+}
+
+/**
+ * suspend_device_irqs - disable all currently enabled interrupt lines
+ *
+ * During system-wide suspend or hibernation device drivers need to be
+ * prevented from receiving interrupts and this function is provided
+ * for this purpose.
+ *
+ * So we disable all interrupts and mark them IRQS_SUSPENDED except
+ * for those which are unused, those which are marked as not
+ * suspendable via an interrupt request with the flag IRQF_NO_SUSPEND
+ * set and those which are marked as active wakeup sources.
+ *
+ * The active wakeup sources are handled by the flow handler entry
+ * code which checks for the IRQD_WAKEUP_ARMED flag, suspends the
+ * interrupt and notifies the pm core about the wakeup.
+ */
+void suspend_device_irqs(void)
+{
+	struct irq_desc *desc;
+	int irq;
+
+	for_each_irq_desc(irq, desc) {
+		unsigned long flags;
+		bool sync;
+
+		if (irq_settings_is_nested_thread(desc))
+			continue;
+		raw_spin_lock_irqsave(&desc->lock, flags);
+		sync = suspend_device_irq(desc);
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+		if (sync)
+			synchronize_irq(irq);
+	}
+}
+
+static void resume_irq(struct irq_desc *desc)
+{
+	struct irq_data *irqd = &desc->irq_data;
+
+	irqd_clear(irqd, IRQD_WAKEUP_ARMED);
+
+	if (irqd_is_enabled_on_suspend(irqd)) {
+		/*
+		 * Interrupt marked for wakeup was enabled during suspend
+		 * entry. Disable such interrupts to restore them back to
+		 * original state.
+		 */
+		__disable_irq(desc);
+		irqd_clear(irqd, IRQD_IRQ_ENABLED_ON_SUSPEND);
+	}
+
+	if (desc->istate & IRQS_SUSPENDED)
+		goto resume;
+
+	/* Force resume the interrupt? */
+	if (!desc->force_resume_depth)
+		return;
+
+	/* Pretend that it got disabled ! */
+	desc->depth++;
+	irq_state_set_disabled(desc);
+	irq_state_set_masked(desc);
+resume:
+	desc->istate &= ~IRQS_SUSPENDED;
+	__enable_irq(desc);
+}
+
+static void resume_irqs(bool want_early)
+{
+	struct irq_desc *desc;
+	int irq;
+
+	for_each_irq_desc(irq, desc) {
+		unsigned long flags;
+		bool is_early = desc->action &&
+			desc->action->flags & IRQF_EARLY_RESUME;
+
+		if (!is_early && want_early)
+			continue;
+		if (irq_settings_is_nested_thread(desc))
+			continue;
+
+		raw_spin_lock_irqsave(&desc->lock, flags);
+		resume_irq(desc);
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+	}
+}
+
+/**
+ * rearm_wake_irq - rearm a wakeup interrupt line after signaling wakeup
+ * @irq: Interrupt to rearm
+ */
+void rearm_wake_irq(unsigned int irq)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
+
+	if (!desc)
+		return;
+
+	if (!(desc->istate & IRQS_SUSPENDED) ||
+	    !irqd_is_wakeup_set(&desc->irq_data))
+		goto unlock;
+
+	desc->istate &= ~IRQS_SUSPENDED;
+	irqd_set(&desc->irq_data, IRQD_WAKEUP_ARMED);
+	__enable_irq(desc);
+
+unlock:
+	irq_put_desc_busunlock(desc, flags);
+}
+
+/**
+ * irq_pm_syscore_resume - enable interrupt lines early
+ *
+ * Enable all interrupt lines with %IRQF_EARLY_RESUME set.
+ */
+static void irq_pm_syscore_resume(void)
+{
+	resume_irqs(true);
+}
+
+static struct syscore_ops irq_pm_syscore_ops = {
+	.resume		= irq_pm_syscore_resume,
+};
+
+static int __init irq_pm_init_ops(void)
+{
+	register_syscore_ops(&irq_pm_syscore_ops);
+	return 0;
+}
+
+device_initcall(irq_pm_init_ops);
+
+/**
+ * resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
+ *
+ * Enable all non-%IRQF_EARLY_RESUME interrupt lines previously
+ * disabled by suspend_device_irqs() that have the IRQS_SUSPENDED flag
+ * set as well as those with %IRQF_FORCE_RESUME.
+ */
+void resume_device_irqs(void)
+{
+	resume_irqs(false);
+}
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
new file mode 100644
index 000000000..623b8136e
--- /dev/null
+++ b/kernel/irq/proc.c
@@ -0,0 +1,538 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
+ *
+ * This file contains the /proc/irq/ handling code.
+ */
+
+#include <linux/irq.h>
+#include <linux/gfp.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+#include <linux/mutex.h>
+
+#include "internals.h"
+
+/*
+ * Access rules:
+ *
+ * procfs protects read/write of /proc/irq/N/ files against a
+ * concurrent free of the interrupt descriptor. remove_proc_entry()
+ * immediately prevents new read/writes to happen and waits for
+ * already running read/write functions to complete.
+ *
+ * We remove the proc entries first and then delete the interrupt
+ * descriptor from the radix tree and free it. So it is guaranteed
+ * that irq_to_desc(N) is valid as long as the read/writes are
+ * permitted by procfs.
+ *
+ * The read from /proc/interrupts is a different problem because there
+ * is no protection. So the lookup and the access to irqdesc
+ * information must be protected by sparse_irq_lock.
+ */
+static struct proc_dir_entry *root_irq_dir;
+
+#ifdef CONFIG_SMP
+
+enum {
+	AFFINITY,
+	AFFINITY_LIST,
+	EFFECTIVE,
+	EFFECTIVE_LIST,
+};
+
+static int show_irq_affinity(int type, struct seq_file *m)
+{
+	struct irq_desc *desc = irq_to_desc((long)m->private);
+	const struct cpumask *mask;
+
+	switch (type) {
+	case AFFINITY:
+	case AFFINITY_LIST:
+		mask = desc->irq_common_data.affinity;
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+		if (irqd_is_setaffinity_pending(&desc->irq_data))
+			mask = desc->pending_mask;
+#endif
+		break;
+	case EFFECTIVE:
+	case EFFECTIVE_LIST:
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+		mask = irq_data_get_effective_affinity_mask(&desc->irq_data);
+		break;
+#endif
+	default:
+		return -EINVAL;
+	}
+
+	switch (type) {
+	case AFFINITY_LIST:
+	case EFFECTIVE_LIST:
+		seq_printf(m, "%*pbl\n", cpumask_pr_args(mask));
+		break;
+	case AFFINITY:
+	case EFFECTIVE:
+		seq_printf(m, "%*pb\n", cpumask_pr_args(mask));
+		break;
+	}
+	return 0;
+}
+
+static int irq_affinity_hint_proc_show(struct seq_file *m, void *v)
+{
+	struct irq_desc *desc = irq_to_desc((long)m->private);
+	unsigned long flags;
+	cpumask_var_t mask;
+
+	if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	raw_spin_lock_irqsave(&desc->lock, flags);
+	if (desc->affinity_hint)
+		cpumask_copy(mask, desc->affinity_hint);
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+	seq_printf(m, "%*pb\n", cpumask_pr_args(mask));
+	free_cpumask_var(mask);
+
+	return 0;
+}
+
+int no_irq_affinity;
+static int irq_affinity_proc_show(struct seq_file *m, void *v)
+{
+	return show_irq_affinity(AFFINITY, m);
+}
+
+static int irq_affinity_list_proc_show(struct seq_file *m, void *v)
+{
+	return show_irq_affinity(AFFINITY_LIST, m);
+}
+
+#ifndef CONFIG_AUTO_IRQ_AFFINITY
+static inline int irq_select_affinity_usr(unsigned int irq)
+{
+	/*
+	 * If the interrupt is started up already then this fails. The
+	 * interrupt is assigned to an online CPU already. There is no
+	 * point to move it around randomly. Tell user space that the
+	 * selected mask is bogus.
+	 *
+	 * If not then any change to the affinity is pointless because the
+	 * startup code invokes irq_setup_affinity() which will select
+	 * a online CPU anyway.
+	 */
+	return -EINVAL;
+}
+#else
+/* ALPHA magic affinity auto selector. Keep it for historical reasons. */
+static inline int irq_select_affinity_usr(unsigned int irq)
+{
+	return irq_select_affinity(irq);
+}
+#endif
+
+static ssize_t write_irq_affinity(int type, struct file *file,
+		const char __user *buffer, size_t count, loff_t *pos)
+{
+	unsigned int irq = (int)(long)pde_data(file_inode(file));
+	cpumask_var_t new_value;
+	int err;
+
+	if (!irq_can_set_affinity_usr(irq) || no_irq_affinity)
+		return -EIO;
+
+	if (!zalloc_cpumask_var(&new_value, GFP_KERNEL))
+		return -ENOMEM;
+
+	if (type)
+		err = cpumask_parselist_user(buffer, count, new_value);
+	else
+		err = cpumask_parse_user(buffer, count, new_value);
+	if (err)
+		goto free_cpumask;
+
+	/*
+	 * Do not allow disabling IRQs completely - it's a too easy
+	 * way to make the system unusable accidentally :-) At least
+	 * one online CPU still has to be targeted.
+	 */
+	if (!cpumask_intersects(new_value, cpu_online_mask)) {
+		/*
+		 * Special case for empty set - allow the architecture code
+		 * to set default SMP affinity.
+		 */
+		err = irq_select_affinity_usr(irq) ? -EINVAL : count;
+	} else {
+		err = irq_set_affinity(irq, new_value);
+		if (!err)
+			err = count;
+	}
+
+free_cpumask:
+	free_cpumask_var(new_value);
+	return err;
+}
+
+static ssize_t irq_affinity_proc_write(struct file *file,
+		const char __user *buffer, size_t count, loff_t *pos)
+{
+	return write_irq_affinity(0, file, buffer, count, pos);
+}
+
+static ssize_t irq_affinity_list_proc_write(struct file *file,
+		const char __user *buffer, size_t count, loff_t *pos)
+{
+	return write_irq_affinity(1, file, buffer, count, pos);
+}
+
+static int irq_affinity_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, irq_affinity_proc_show, pde_data(inode));
+}
+
+static int irq_affinity_list_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, irq_affinity_list_proc_show, pde_data(inode));
+}
+
+static const struct proc_ops irq_affinity_proc_ops = {
+	.proc_open	= irq_affinity_proc_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= single_release,
+	.proc_write	= irq_affinity_proc_write,
+};
+
+static const struct proc_ops irq_affinity_list_proc_ops = {
+	.proc_open	= irq_affinity_list_proc_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= single_release,
+	.proc_write	= irq_affinity_list_proc_write,
+};
+
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+static int irq_effective_aff_proc_show(struct seq_file *m, void *v)
+{
+	return show_irq_affinity(EFFECTIVE, m);
+}
+
+static int irq_effective_aff_list_proc_show(struct seq_file *m, void *v)
+{
+	return show_irq_affinity(EFFECTIVE_LIST, m);
+}
+#endif
+
+static int default_affinity_show(struct seq_file *m, void *v)
+{
+	seq_printf(m, "%*pb\n", cpumask_pr_args(irq_default_affinity));
+	return 0;
+}
+
+static ssize_t default_affinity_write(struct file *file,
+		const char __user *buffer, size_t count, loff_t *ppos)
+{
+	cpumask_var_t new_value;
+	int err;
+
+	if (!zalloc_cpumask_var(&new_value, GFP_KERNEL))
+		return -ENOMEM;
+
+	err = cpumask_parse_user(buffer, count, new_value);
+	if (err)
+		goto out;
+
+	/*
+	 * Do not allow disabling IRQs completely - it's a too easy
+	 * way to make the system unusable accidentally :-) At least
+	 * one online CPU still has to be targeted.
+	 */
+	if (!cpumask_intersects(new_value, cpu_online_mask)) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	cpumask_copy(irq_default_affinity, new_value);
+	err = count;
+
+out:
+	free_cpumask_var(new_value);
+	return err;
+}
+
+static int default_affinity_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, default_affinity_show, pde_data(inode));
+}
+
+static const struct proc_ops default_affinity_proc_ops = {
+	.proc_open	= default_affinity_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= single_release,
+	.proc_write	= default_affinity_write,
+};
+
+static int irq_node_proc_show(struct seq_file *m, void *v)
+{
+	struct irq_desc *desc = irq_to_desc((long) m->private);
+
+	seq_printf(m, "%d\n", irq_desc_get_node(desc));
+	return 0;
+}
+#endif
+
+static int irq_spurious_proc_show(struct seq_file *m, void *v)
+{
+	struct irq_desc *desc = irq_to_desc((long) m->private);
+
+	seq_printf(m, "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n",
+		   desc->irq_count, desc->irqs_unhandled,
+		   jiffies_to_msecs(desc->last_unhandled));
+	return 0;
+}
+
+#define MAX_NAMELEN 128
+
+static int name_unique(unsigned int irq, struct irqaction *new_action)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	struct irqaction *action;
+	unsigned long flags;
+	int ret = 1;
+
+	raw_spin_lock_irqsave(&desc->lock, flags);
+	for_each_action_of_desc(desc, action) {
+		if ((action != new_action) && action->name &&
+				!strcmp(new_action->name, action->name)) {
+			ret = 0;
+			break;
+		}
+	}
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+	return ret;
+}
+
+void register_handler_proc(unsigned int irq, struct irqaction *action)
+{
+	char name [MAX_NAMELEN];
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	if (!desc->dir || action->dir || !action->name ||
+					!name_unique(irq, action))
+		return;
+
+	snprintf(name, MAX_NAMELEN, "%s", action->name);
+
+	/* create /proc/irq/1234/handler/ */
+	action->dir = proc_mkdir(name, desc->dir);
+}
+
+#undef MAX_NAMELEN
+
+#define MAX_NAMELEN 10
+
+void register_irq_proc(unsigned int irq, struct irq_desc *desc)
+{
+	static DEFINE_MUTEX(register_lock);
+	void __maybe_unused *irqp = (void *)(unsigned long) irq;
+	char name [MAX_NAMELEN];
+
+	if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip))
+		return;
+
+	/*
+	 * irq directories are registered only when a handler is
+	 * added, not when the descriptor is created, so multiple
+	 * tasks might try to register at the same time.
+	 */
+	mutex_lock(&register_lock);
+
+	if (desc->dir)
+		goto out_unlock;
+
+	sprintf(name, "%d", irq);
+
+	/* create /proc/irq/1234 */
+	desc->dir = proc_mkdir(name, root_irq_dir);
+	if (!desc->dir)
+		goto out_unlock;
+
+#ifdef CONFIG_SMP
+	/* create /proc/irq/<irq>/smp_affinity */
+	proc_create_data("smp_affinity", 0644, desc->dir,
+			 &irq_affinity_proc_ops, irqp);
+
+	/* create /proc/irq/<irq>/affinity_hint */
+	proc_create_single_data("affinity_hint", 0444, desc->dir,
+			irq_affinity_hint_proc_show, irqp);
+
+	/* create /proc/irq/<irq>/smp_affinity_list */
+	proc_create_data("smp_affinity_list", 0644, desc->dir,
+			 &irq_affinity_list_proc_ops, irqp);
+
+	proc_create_single_data("node", 0444, desc->dir, irq_node_proc_show,
+			irqp);
+# ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	proc_create_single_data("effective_affinity", 0444, desc->dir,
+			irq_effective_aff_proc_show, irqp);
+	proc_create_single_data("effective_affinity_list", 0444, desc->dir,
+			irq_effective_aff_list_proc_show, irqp);
+# endif
+#endif
+	proc_create_single_data("spurious", 0444, desc->dir,
+			irq_spurious_proc_show, (void *)(long)irq);
+
+out_unlock:
+	mutex_unlock(&register_lock);
+}
+
+void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)
+{
+	char name [MAX_NAMELEN];
+
+	if (!root_irq_dir || !desc->dir)
+		return;
+#ifdef CONFIG_SMP
+	remove_proc_entry("smp_affinity", desc->dir);
+	remove_proc_entry("affinity_hint", desc->dir);
+	remove_proc_entry("smp_affinity_list", desc->dir);
+	remove_proc_entry("node", desc->dir);
+# ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	remove_proc_entry("effective_affinity", desc->dir);
+	remove_proc_entry("effective_affinity_list", desc->dir);
+# endif
+#endif
+	remove_proc_entry("spurious", desc->dir);
+
+	sprintf(name, "%u", irq);
+	remove_proc_entry(name, root_irq_dir);
+}
+
+#undef MAX_NAMELEN
+
+void unregister_handler_proc(unsigned int irq, struct irqaction *action)
+{
+	proc_remove(action->dir);
+}
+
+static void register_default_affinity_proc(void)
+{
+#ifdef CONFIG_SMP
+	proc_create("irq/default_smp_affinity", 0644, NULL,
+		    &default_affinity_proc_ops);
+#endif
+}
+
+void init_irq_proc(void)
+{
+	unsigned int irq;
+	struct irq_desc *desc;
+
+	/* create /proc/irq */
+	root_irq_dir = proc_mkdir("irq", NULL);
+	if (!root_irq_dir)
+		return;
+
+	register_default_affinity_proc();
+
+	/*
+	 * Create entries for all existing IRQs.
+	 */
+	for_each_irq_desc(irq, desc)
+		register_irq_proc(irq, desc);
+}
+
+#ifdef CONFIG_GENERIC_IRQ_SHOW
+
+int __weak arch_show_interrupts(struct seq_file *p, int prec)
+{
+	return 0;
+}
+
+#ifndef ACTUAL_NR_IRQS
+# define ACTUAL_NR_IRQS nr_irqs
+#endif
+
+int show_interrupts(struct seq_file *p, void *v)
+{
+	static int prec;
+
+	unsigned long flags, any_count = 0;
+	int i = *(loff_t *) v, j;
+	struct irqaction *action;
+	struct irq_desc *desc;
+
+	if (i > ACTUAL_NR_IRQS)
+		return 0;
+
+	if (i == ACTUAL_NR_IRQS)
+		return arch_show_interrupts(p, prec);
+
+	/* print header and calculate the width of the first column */
+	if (i == 0) {
+		for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
+			j *= 10;
+
+		seq_printf(p, "%*s", prec + 8, "");
+		for_each_online_cpu(j)
+			seq_printf(p, "CPU%-8d", j);
+		seq_putc(p, '\n');
+	}
+
+	rcu_read_lock();
+	desc = irq_to_desc(i);
+	if (!desc || irq_settings_is_hidden(desc))
+		goto outsparse;
+
+	if (desc->kstat_irqs) {
+		for_each_online_cpu(j)
+			any_count |= data_race(*per_cpu_ptr(desc->kstat_irqs, j));
+	}
+
+	if ((!desc->action || irq_desc_is_chained(desc)) && !any_count)
+		goto outsparse;
+
+	seq_printf(p, "%*d: ", prec, i);
+	for_each_online_cpu(j)
+		seq_printf(p, "%10u ", desc->kstat_irqs ?
+					*per_cpu_ptr(desc->kstat_irqs, j) : 0);
+
+	raw_spin_lock_irqsave(&desc->lock, flags);
+	if (desc->irq_data.chip) {
+		if (desc->irq_data.chip->irq_print_chip)
+			desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);
+		else if (desc->irq_data.chip->name)
+			seq_printf(p, " %8s", desc->irq_data.chip->name);
+		else
+			seq_printf(p, " %8s", "-");
+	} else {
+		seq_printf(p, " %8s", "None");
+	}
+	if (desc->irq_data.domain)
+		seq_printf(p, " %*lu", prec, desc->irq_data.hwirq);
+	else
+		seq_printf(p, " %*s", prec, "");
+#ifdef CONFIG_GENERIC_IRQ_SHOW_LEVEL
+	seq_printf(p, " %-8s", irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge");
+#endif
+	if (desc->name)
+		seq_printf(p, "-%-8s", desc->name);
+
+	action = desc->action;
+	if (action) {
+		seq_printf(p, "  %s", action->name);
+		while ((action = action->next) != NULL)
+			seq_printf(p, ", %s", action->name);
+	}
+
+	seq_putc(p, '\n');
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+outsparse:
+	rcu_read_unlock();
+	return 0;
+}
+#endif
diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
new file mode 100644
index 000000000..0c46e9fe3
--- /dev/null
+++ b/kernel/irq/resend.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
+ * Copyright (C) 2005-2006, Thomas Gleixner
+ *
+ * This file contains the IRQ-resend code
+ *
+ * If the interrupt is waiting to be processed, we try to re-run it.
+ * We can't directly run it from here since the caller might be in an
+ * interrupt-protected region. Not all irq controller chips can
+ * retrigger interrupts at the hardware level, so in those cases
+ * we allow the resending of IRQs via a tasklet.
+ */
+
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/interrupt.h>
+
+#include "internals.h"
+
+#ifdef CONFIG_HARDIRQS_SW_RESEND
+
+/* Bitmap to handle software resend of interrupts: */
+static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS);
+
+/*
+ * Run software resends of IRQ's
+ */
+static void resend_irqs(struct tasklet_struct *unused)
+{
+	struct irq_desc *desc;
+	int irq;
+
+	while (!bitmap_empty(irqs_resend, nr_irqs)) {
+		irq = find_first_bit(irqs_resend, nr_irqs);
+		clear_bit(irq, irqs_resend);
+		desc = irq_to_desc(irq);
+		if (!desc)
+			continue;
+		local_irq_disable();
+		desc->handle_irq(desc);
+		local_irq_enable();
+	}
+}
+
+/* Tasklet to handle resend: */
+static DECLARE_TASKLET(resend_tasklet, resend_irqs);
+
+static int irq_sw_resend(struct irq_desc *desc)
+{
+	unsigned int irq = irq_desc_get_irq(desc);
+
+	/*
+	 * Validate whether this interrupt can be safely injected from
+	 * non interrupt context
+	 */
+	if (handle_enforce_irqctx(&desc->irq_data))
+		return -EINVAL;
+
+	/*
+	 * If the interrupt is running in the thread context of the parent
+	 * irq we need to be careful, because we cannot trigger it
+	 * directly.
+	 */
+	if (irq_settings_is_nested_thread(desc)) {
+		/*
+		 * If the parent_irq is valid, we retrigger the parent,
+		 * otherwise we do nothing.
+		 */
+		if (!desc->parent_irq)
+			return -EINVAL;
+		irq = desc->parent_irq;
+	}
+
+	/* Set it pending and activate the softirq: */
+	set_bit(irq, irqs_resend);
+	tasklet_schedule(&resend_tasklet);
+	return 0;
+}
+
+#else
+static int irq_sw_resend(struct irq_desc *desc)
+{
+	return -EINVAL;
+}
+#endif
+
+static int try_retrigger(struct irq_desc *desc)
+{
+	if (desc->irq_data.chip->irq_retrigger)
+		return desc->irq_data.chip->irq_retrigger(&desc->irq_data);
+
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+	return irq_chip_retrigger_hierarchy(&desc->irq_data);
+#else
+	return 0;
+#endif
+}
+
+/*
+ * IRQ resend
+ *
+ * Is called with interrupts disabled and desc->lock held.
+ */
+int check_irq_resend(struct irq_desc *desc, bool inject)
+{
+	int err = 0;
+
+	/*
+	 * We do not resend level type interrupts. Level type interrupts
+	 * are resent by hardware when they are still active. Clear the
+	 * pending bit so suspend/resume does not get confused.
+	 */
+	if (irq_settings_is_level(desc)) {
+		desc->istate &= ~IRQS_PENDING;
+		return -EINVAL;
+	}
+
+	if (desc->istate & IRQS_REPLAY)
+		return -EBUSY;
+
+	if (!(desc->istate & IRQS_PENDING) && !inject)
+		return 0;
+
+	desc->istate &= ~IRQS_PENDING;
+
+	if (!try_retrigger(desc))
+		err = irq_sw_resend(desc);
+
+	/* If the retrigger was successful, mark it with the REPLAY bit */
+	if (!err)
+		desc->istate |= IRQS_REPLAY;
+	return err;
+}
+
+#ifdef CONFIG_GENERIC_IRQ_INJECTION
+/**
+ * irq_inject_interrupt - Inject an interrupt for testing/error injection
+ * @irq:	The interrupt number
+ *
+ * This function must only be used for debug and testing purposes!
+ *
+ * Especially on x86 this can cause a premature completion of an interrupt
+ * affinity change causing the interrupt line to become stale. Very
+ * unlikely, but possible.
+ *
+ * The injection can fail for various reasons:
+ * - Interrupt is not activated
+ * - Interrupt is NMI type or currently replaying
+ * - Interrupt is level type
+ * - Interrupt does not support hardware retrigger and software resend is
+ *   either not enabled or not possible for the interrupt.
+ */
+int irq_inject_interrupt(unsigned int irq)
+{
+	struct irq_desc *desc;
+	unsigned long flags;
+	int err;
+
+	/* Try the state injection hardware interface first */
+	if (!irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true))
+		return 0;
+
+	/* That failed, try via the resend mechanism */
+	desc = irq_get_desc_buslock(irq, &flags, 0);
+	if (!desc)
+		return -EINVAL;
+
+	/*
+	 * Only try to inject when the interrupt is:
+	 *  - not NMI type
+	 *  - activated
+	 */
+	if ((desc->istate & IRQS_NMI) || !irqd_is_activated(&desc->irq_data))
+		err = -EINVAL;
+	else
+		err = check_irq_resend(desc, true);
+
+	irq_put_desc_busunlock(desc, flags);
+	return err;
+}
+EXPORT_SYMBOL_GPL(irq_inject_interrupt);
+#endif
diff --git a/kernel/irq/settings.h b/kernel/irq/settings.h
new file mode 100644
index 000000000..7b7efb1a1
--- /dev/null
+++ b/kernel/irq/settings.h
@@ -0,0 +1,188 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Internal header to deal with irq_desc->status which will be renamed
+ * to irq_desc->settings.
+ */
+enum {
+	_IRQ_DEFAULT_INIT_FLAGS	= IRQ_DEFAULT_INIT_FLAGS,
+	_IRQ_PER_CPU		= IRQ_PER_CPU,
+	_IRQ_LEVEL		= IRQ_LEVEL,
+	_IRQ_NOPROBE		= IRQ_NOPROBE,
+	_IRQ_NOREQUEST		= IRQ_NOREQUEST,
+	_IRQ_NOTHREAD		= IRQ_NOTHREAD,
+	_IRQ_NOAUTOEN		= IRQ_NOAUTOEN,
+	_IRQ_MOVE_PCNTXT	= IRQ_MOVE_PCNTXT,
+	_IRQ_NO_BALANCING	= IRQ_NO_BALANCING,
+	_IRQ_NESTED_THREAD	= IRQ_NESTED_THREAD,
+	_IRQ_PER_CPU_DEVID	= IRQ_PER_CPU_DEVID,
+	_IRQ_IS_POLLED		= IRQ_IS_POLLED,
+	_IRQ_DISABLE_UNLAZY	= IRQ_DISABLE_UNLAZY,
+	_IRQ_HIDDEN		= IRQ_HIDDEN,
+	_IRQ_NO_DEBUG		= IRQ_NO_DEBUG,
+	_IRQF_MODIFY_MASK	= IRQF_MODIFY_MASK,
+};
+
+#define IRQ_PER_CPU		GOT_YOU_MORON
+#define IRQ_NO_BALANCING	GOT_YOU_MORON
+#define IRQ_LEVEL		GOT_YOU_MORON
+#define IRQ_NOPROBE		GOT_YOU_MORON
+#define IRQ_NOREQUEST		GOT_YOU_MORON
+#define IRQ_NOTHREAD		GOT_YOU_MORON
+#define IRQ_NOAUTOEN		GOT_YOU_MORON
+#define IRQ_NESTED_THREAD	GOT_YOU_MORON
+#define IRQ_PER_CPU_DEVID	GOT_YOU_MORON
+#define IRQ_IS_POLLED		GOT_YOU_MORON
+#define IRQ_DISABLE_UNLAZY	GOT_YOU_MORON
+#define IRQ_HIDDEN		GOT_YOU_MORON
+#define IRQ_NO_DEBUG		GOT_YOU_MORON
+#undef IRQF_MODIFY_MASK
+#define IRQF_MODIFY_MASK	GOT_YOU_MORON
+
+static inline void
+irq_settings_clr_and_set(struct irq_desc *desc, u32 clr, u32 set)
+{
+	desc->status_use_accessors &= ~(clr & _IRQF_MODIFY_MASK);
+	desc->status_use_accessors |= (set & _IRQF_MODIFY_MASK);
+}
+
+static inline bool irq_settings_is_per_cpu(struct irq_desc *desc)
+{
+	return desc->status_use_accessors & _IRQ_PER_CPU;
+}
+
+static inline bool irq_settings_is_per_cpu_devid(struct irq_desc *desc)
+{
+	return desc->status_use_accessors & _IRQ_PER_CPU_DEVID;
+}
+
+static inline void irq_settings_set_per_cpu(struct irq_desc *desc)
+{
+	desc->status_use_accessors |= _IRQ_PER_CPU;
+}
+
+static inline void irq_settings_set_no_balancing(struct irq_desc *desc)
+{
+	desc->status_use_accessors |= _IRQ_NO_BALANCING;
+}
+
+static inline bool irq_settings_has_no_balance_set(struct irq_desc *desc)
+{
+	return desc->status_use_accessors & _IRQ_NO_BALANCING;
+}
+
+static inline u32 irq_settings_get_trigger_mask(struct irq_desc *desc)
+{
+	return desc->status_use_accessors & IRQ_TYPE_SENSE_MASK;
+}
+
+static inline void
+irq_settings_set_trigger_mask(struct irq_desc *desc, u32 mask)
+{
+	desc->status_use_accessors &= ~IRQ_TYPE_SENSE_MASK;
+	desc->status_use_accessors |= mask & IRQ_TYPE_SENSE_MASK;
+}
+
+static inline bool irq_settings_is_level(struct irq_desc *desc)
+{
+	return desc->status_use_accessors & _IRQ_LEVEL;
+}
+
+static inline void irq_settings_clr_level(struct irq_desc *desc)
+{
+	desc->status_use_accessors &= ~_IRQ_LEVEL;
+}
+
+static inline void irq_settings_set_level(struct irq_desc *desc)
+{
+	desc->status_use_accessors |= _IRQ_LEVEL;
+}
+
+static inline bool irq_settings_can_request(struct irq_desc *desc)
+{
+	return !(desc->status_use_accessors & _IRQ_NOREQUEST);
+}
+
+static inline void irq_settings_clr_norequest(struct irq_desc *desc)
+{
+	desc->status_use_accessors &= ~_IRQ_NOREQUEST;
+}
+
+static inline void irq_settings_set_norequest(struct irq_desc *desc)
+{
+	desc->status_use_accessors |= _IRQ_NOREQUEST;
+}
+
+static inline bool irq_settings_can_thread(struct irq_desc *desc)
+{
+	return !(desc->status_use_accessors & _IRQ_NOTHREAD);
+}
+
+static inline void irq_settings_clr_nothread(struct irq_desc *desc)
+{
+	desc->status_use_accessors &= ~_IRQ_NOTHREAD;
+}
+
+static inline void irq_settings_set_nothread(struct irq_desc *desc)
+{
+	desc->status_use_accessors |= _IRQ_NOTHREAD;
+}
+
+static inline bool irq_settings_can_probe(struct irq_desc *desc)
+{
+	return !(desc->status_use_accessors & _IRQ_NOPROBE);
+}
+
+static inline void irq_settings_clr_noprobe(struct irq_desc *desc)
+{
+	desc->status_use_accessors &= ~_IRQ_NOPROBE;
+}
+
+static inline void irq_settings_set_noprobe(struct irq_desc *desc)
+{
+	desc->status_use_accessors |= _IRQ_NOPROBE;
+}
+
+static inline bool irq_settings_can_move_pcntxt(struct irq_desc *desc)
+{
+	return desc->status_use_accessors & _IRQ_MOVE_PCNTXT;
+}
+
+static inline bool irq_settings_can_autoenable(struct irq_desc *desc)
+{
+	return !(desc->status_use_accessors & _IRQ_NOAUTOEN);
+}
+
+static inline bool irq_settings_is_nested_thread(struct irq_desc *desc)
+{
+	return desc->status_use_accessors & _IRQ_NESTED_THREAD;
+}
+
+static inline bool irq_settings_is_polled(struct irq_desc *desc)
+{
+	return desc->status_use_accessors & _IRQ_IS_POLLED;
+}
+
+static inline bool irq_settings_disable_unlazy(struct irq_desc *desc)
+{
+	return desc->status_use_accessors & _IRQ_DISABLE_UNLAZY;
+}
+
+static inline void irq_settings_clr_disable_unlazy(struct irq_desc *desc)
+{
+	desc->status_use_accessors &= ~_IRQ_DISABLE_UNLAZY;
+}
+
+static inline bool irq_settings_is_hidden(struct irq_desc *desc)
+{
+	return desc->status_use_accessors & _IRQ_HIDDEN;
+}
+
+static inline void irq_settings_set_no_debug(struct irq_desc *desc)
+{
+	desc->status_use_accessors |= _IRQ_NO_DEBUG;
+}
+
+static inline bool irq_settings_no_debug(struct irq_desc *desc)
+{
+	return desc->status_use_accessors & _IRQ_NO_DEBUG;
+}
diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
new file mode 100644
index 000000000..02b2daf07
--- /dev/null
+++ b/kernel/irq/spurious.c
@@ -0,0 +1,478 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
+ *
+ * This file contains spurious interrupt handling.
+ */
+
+#include <linux/jiffies.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/moduleparam.h>
+#include <linux/timer.h>
+
+#include "internals.h"
+
+static int irqfixup __read_mostly;
+
+#define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
+static void poll_spurious_irqs(struct timer_list *unused);
+static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs);
+static int irq_poll_cpu;
+static atomic_t irq_poll_active;
+
+/*
+ * We wait here for a poller to finish.
+ *
+ * If the poll runs on this CPU, then we yell loudly and return
+ * false. That will leave the interrupt line disabled in the worst
+ * case, but it should never happen.
+ *
+ * We wait until the poller is done and then recheck disabled and
+ * action (about to be disabled). Only if it's still active, we return
+ * true and let the handler run.
+ */
+bool irq_wait_for_poll(struct irq_desc *desc)
+	__must_hold(&desc->lock)
+{
+	if (WARN_ONCE(irq_poll_cpu == smp_processor_id(),
+		      "irq poll in progress on cpu %d for irq %d\n",
+		      smp_processor_id(), desc->irq_data.irq))
+		return false;
+
+#ifdef CONFIG_SMP
+	do {
+		raw_spin_unlock(&desc->lock);
+		while (irqd_irq_inprogress(&desc->irq_data))
+			cpu_relax();
+		raw_spin_lock(&desc->lock);
+	} while (irqd_irq_inprogress(&desc->irq_data));
+	/* Might have been disabled in meantime */
+	return !irqd_irq_disabled(&desc->irq_data) && desc->action;
+#else
+	return false;
+#endif
+}
+
+
+/*
+ * Recovery handler for misrouted interrupts.
+ */
+static int try_one_irq(struct irq_desc *desc, bool force)
+{
+	irqreturn_t ret = IRQ_NONE;
+	struct irqaction *action;
+
+	raw_spin_lock(&desc->lock);
+
+	/*
+	 * PER_CPU, nested thread interrupts and interrupts explicitly
+	 * marked polled are excluded from polling.
+	 */
+	if (irq_settings_is_per_cpu(desc) ||
+	    irq_settings_is_nested_thread(desc) ||
+	    irq_settings_is_polled(desc))
+		goto out;
+
+	/*
+	 * Do not poll disabled interrupts unless the spurious
+	 * disabled poller asks explicitly.
+	 */
+	if (irqd_irq_disabled(&desc->irq_data) && !force)
+		goto out;
+
+	/*
+	 * All handlers must agree on IRQF_SHARED, so we test just the
+	 * first.
+	 */
+	action = desc->action;
+	if (!action || !(action->flags & IRQF_SHARED) ||
+	    (action->flags & __IRQF_TIMER))
+		goto out;
+
+	/* Already running on another processor */
+	if (irqd_irq_inprogress(&desc->irq_data)) {
+		/*
+		 * Already running: If it is shared get the other
+		 * CPU to go looking for our mystery interrupt too
+		 */
+		desc->istate |= IRQS_PENDING;
+		goto out;
+	}
+
+	/* Mark it poll in progress */
+	desc->istate |= IRQS_POLL_INPROGRESS;
+	do {
+		if (handle_irq_event(desc) == IRQ_HANDLED)
+			ret = IRQ_HANDLED;
+		/* Make sure that there is still a valid action */
+		action = desc->action;
+	} while ((desc->istate & IRQS_PENDING) && action);
+	desc->istate &= ~IRQS_POLL_INPROGRESS;
+out:
+	raw_spin_unlock(&desc->lock);
+	return ret == IRQ_HANDLED;
+}
+
+static int misrouted_irq(int irq)
+{
+	struct irq_desc *desc;
+	int i, ok = 0;
+
+	if (atomic_inc_return(&irq_poll_active) != 1)
+		goto out;
+
+	irq_poll_cpu = smp_processor_id();
+
+	for_each_irq_desc(i, desc) {
+		if (!i)
+			 continue;
+
+		if (i == irq)	/* Already tried */
+			continue;
+
+		if (try_one_irq(desc, false))
+			ok = 1;
+	}
+out:
+	atomic_dec(&irq_poll_active);
+	/* So the caller can adjust the irq error counts */
+	return ok;
+}
+
+static void poll_spurious_irqs(struct timer_list *unused)
+{
+	struct irq_desc *desc;
+	int i;
+
+	if (atomic_inc_return(&irq_poll_active) != 1)
+		goto out;
+	irq_poll_cpu = smp_processor_id();
+
+	for_each_irq_desc(i, desc) {
+		unsigned int state;
+
+		if (!i)
+			 continue;
+
+		/* Racy but it doesn't matter */
+		state = desc->istate;
+		barrier();
+		if (!(state & IRQS_SPURIOUS_DISABLED))
+			continue;
+
+		local_irq_disable();
+		try_one_irq(desc, true);
+		local_irq_enable();
+	}
+out:
+	atomic_dec(&irq_poll_active);
+	mod_timer(&poll_spurious_irq_timer,
+		  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
+}
+
+static inline int bad_action_ret(irqreturn_t action_ret)
+{
+	unsigned int r = action_ret;
+
+	if (likely(r <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
+		return 0;
+	return 1;
+}
+
+/*
+ * If 99,900 of the previous 100,000 interrupts have not been handled
+ * then assume that the IRQ is stuck in some manner. Drop a diagnostic
+ * and try to turn the IRQ off.
+ *
+ * (The other 100-of-100,000 interrupts may have been a correctly
+ *  functioning device sharing an IRQ with the failing one)
+ */
+static void __report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
+{
+	unsigned int irq = irq_desc_get_irq(desc);
+	struct irqaction *action;
+	unsigned long flags;
+
+	if (bad_action_ret(action_ret)) {
+		printk(KERN_ERR "irq event %d: bogus return value %x\n",
+				irq, action_ret);
+	} else {
+		printk(KERN_ERR "irq %d: nobody cared (try booting with "
+				"the \"irqpoll\" option)\n", irq);
+	}
+	dump_stack();
+	printk(KERN_ERR "handlers:\n");
+
+	/*
+	 * We need to take desc->lock here. note_interrupt() is called
+	 * w/o desc->lock held, but IRQ_PROGRESS set. We might race
+	 * with something else removing an action. It's ok to take
+	 * desc->lock here. See synchronize_irq().
+	 */
+	raw_spin_lock_irqsave(&desc->lock, flags);
+	for_each_action_of_desc(desc, action) {
+		printk(KERN_ERR "[<%p>] %ps", action->handler, action->handler);
+		if (action->thread_fn)
+			printk(KERN_CONT " threaded [<%p>] %ps",
+					action->thread_fn, action->thread_fn);
+		printk(KERN_CONT "\n");
+	}
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
+}
+
+static void report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
+{
+	static int count = 100;
+
+	if (count > 0) {
+		count--;
+		__report_bad_irq(desc, action_ret);
+	}
+}
+
+static inline int
+try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
+		  irqreturn_t action_ret)
+{
+	struct irqaction *action;
+
+	if (!irqfixup)
+		return 0;
+
+	/* We didn't actually handle the IRQ - see if it was misrouted? */
+	if (action_ret == IRQ_NONE)
+		return 1;
+
+	/*
+	 * But for 'irqfixup == 2' we also do it for handled interrupts if
+	 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
+	 * traditional PC timer interrupt.. Legacy)
+	 */
+	if (irqfixup < 2)
+		return 0;
+
+	if (!irq)
+		return 1;
+
+	/*
+	 * Since we don't get the descriptor lock, "action" can
+	 * change under us.  We don't really care, but we don't
+	 * want to follow a NULL pointer. So tell the compiler to
+	 * just load it once by using a barrier.
+	 */
+	action = desc->action;
+	barrier();
+	return action && (action->flags & IRQF_IRQPOLL);
+}
+
+#define SPURIOUS_DEFERRED	0x80000000
+
+void note_interrupt(struct irq_desc *desc, irqreturn_t action_ret)
+{
+	unsigned int irq;
+
+	if (desc->istate & IRQS_POLL_INPROGRESS ||
+	    irq_settings_is_polled(desc))
+		return;
+
+	if (bad_action_ret(action_ret)) {
+		report_bad_irq(desc, action_ret);
+		return;
+	}
+
+	/*
+	 * We cannot call note_interrupt from the threaded handler
+	 * because we need to look at the compound of all handlers
+	 * (primary and threaded). Aside of that in the threaded
+	 * shared case we have no serialization against an incoming
+	 * hardware interrupt while we are dealing with a threaded
+	 * result.
+	 *
+	 * So in case a thread is woken, we just note the fact and
+	 * defer the analysis to the next hardware interrupt.
+	 *
+	 * The threaded handlers store whether they successfully
+	 * handled an interrupt and we check whether that number
+	 * changed versus the last invocation.
+	 *
+	 * We could handle all interrupts with the delayed by one
+	 * mechanism, but for the non forced threaded case we'd just
+	 * add pointless overhead to the straight hardirq interrupts
+	 * for the sake of a few lines less code.
+	 */
+	if (action_ret & IRQ_WAKE_THREAD) {
+		/*
+		 * There is a thread woken. Check whether one of the
+		 * shared primary handlers returned IRQ_HANDLED. If
+		 * not we defer the spurious detection to the next
+		 * interrupt.
+		 */
+		if (action_ret == IRQ_WAKE_THREAD) {
+			int handled;
+			/*
+			 * We use bit 31 of thread_handled_last to
+			 * denote the deferred spurious detection
+			 * active. No locking necessary as
+			 * thread_handled_last is only accessed here
+			 * and we have the guarantee that hard
+			 * interrupts are not reentrant.
+			 */
+			if (!(desc->threads_handled_last & SPURIOUS_DEFERRED)) {
+				desc->threads_handled_last |= SPURIOUS_DEFERRED;
+				return;
+			}
+			/*
+			 * Check whether one of the threaded handlers
+			 * returned IRQ_HANDLED since the last
+			 * interrupt happened.
+			 *
+			 * For simplicity we just set bit 31, as it is
+			 * set in threads_handled_last as well. So we
+			 * avoid extra masking. And we really do not
+			 * care about the high bits of the handled
+			 * count. We just care about the count being
+			 * different than the one we saw before.
+			 */
+			handled = atomic_read(&desc->threads_handled);
+			handled |= SPURIOUS_DEFERRED;
+			if (handled != desc->threads_handled_last) {
+				action_ret = IRQ_HANDLED;
+				/*
+				 * Note: We keep the SPURIOUS_DEFERRED
+				 * bit set. We are handling the
+				 * previous invocation right now.
+				 * Keep it for the current one, so the
+				 * next hardware interrupt will
+				 * account for it.
+				 */
+				desc->threads_handled_last = handled;
+			} else {
+				/*
+				 * None of the threaded handlers felt
+				 * responsible for the last interrupt
+				 *
+				 * We keep the SPURIOUS_DEFERRED bit
+				 * set in threads_handled_last as we
+				 * need to account for the current
+				 * interrupt as well.
+				 */
+				action_ret = IRQ_NONE;
+			}
+		} else {
+			/*
+			 * One of the primary handlers returned
+			 * IRQ_HANDLED. So we don't care about the
+			 * threaded handlers on the same line. Clear
+			 * the deferred detection bit.
+			 *
+			 * In theory we could/should check whether the
+			 * deferred bit is set and take the result of
+			 * the previous run into account here as
+			 * well. But it's really not worth the
+			 * trouble. If every other interrupt is
+			 * handled we never trigger the spurious
+			 * detector. And if this is just the one out
+			 * of 100k unhandled ones which is handled
+			 * then we merily delay the spurious detection
+			 * by one hard interrupt. Not a real problem.
+			 */
+			desc->threads_handled_last &= ~SPURIOUS_DEFERRED;
+		}
+	}
+
+	if (unlikely(action_ret == IRQ_NONE)) {
+		/*
+		 * If we are seeing only the odd spurious IRQ caused by
+		 * bus asynchronicity then don't eventually trigger an error,
+		 * otherwise the counter becomes a doomsday timer for otherwise
+		 * working systems
+		 */
+		if (time_after(jiffies, desc->last_unhandled + HZ/10))
+			desc->irqs_unhandled = 1;
+		else
+			desc->irqs_unhandled++;
+		desc->last_unhandled = jiffies;
+	}
+
+	irq = irq_desc_get_irq(desc);
+	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
+		int ok = misrouted_irq(irq);
+		if (action_ret == IRQ_NONE)
+			desc->irqs_unhandled -= ok;
+	}
+
+	if (likely(!desc->irqs_unhandled))
+		return;
+
+	/* Now getting into unhandled irq detection */
+	desc->irq_count++;
+	if (likely(desc->irq_count < 100000))
+		return;
+
+	desc->irq_count = 0;
+	if (unlikely(desc->irqs_unhandled > 99900)) {
+		/*
+		 * The interrupt is stuck
+		 */
+		__report_bad_irq(desc, action_ret);
+		/*
+		 * Now kill the IRQ
+		 */
+		printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
+		desc->istate |= IRQS_SPURIOUS_DISABLED;
+		desc->depth++;
+		irq_disable(desc);
+
+		mod_timer(&poll_spurious_irq_timer,
+			  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
+	}
+	desc->irqs_unhandled = 0;
+}
+
+bool noirqdebug __read_mostly;
+
+int noirqdebug_setup(char *str)
+{
+	noirqdebug = 1;
+	printk(KERN_INFO "IRQ lockup detection disabled\n");
+
+	return 1;
+}
+
+__setup("noirqdebug", noirqdebug_setup);
+module_param(noirqdebug, bool, 0644);
+MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
+
+static int __init irqfixup_setup(char *str)
+{
+	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+		pr_warn("irqfixup boot option not supported with PREEMPT_RT\n");
+		return 1;
+	}
+	irqfixup = 1;
+	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
+	printk(KERN_WARNING "This may impact system performance.\n");
+
+	return 1;
+}
+
+__setup("irqfixup", irqfixup_setup);
+module_param(irqfixup, int, 0644);
+
+static int __init irqpoll_setup(char *str)
+{
+	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+		pr_warn("irqpoll boot option not supported with PREEMPT_RT\n");
+		return 1;
+	}
+	irqfixup = 2;
+	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
+				"enabled\n");
+	printk(KERN_WARNING "This may significantly impact system "
+				"performance\n");
+	return 1;
+}
+
+__setup("irqpoll", irqpoll_setup);
diff --git a/kernel/irq/timings.c b/kernel/irq/timings.c
new file mode 100644
index 000000000..c43e2ac2f
--- /dev/null
+++ b/kernel/irq/timings.c
@@ -0,0 +1,958 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2016, Linaro Ltd - Daniel Lezcano <daniel.lezcano@linaro.org>
+#define pr_fmt(fmt) "irq_timings: " fmt
+
+#include <linux/kernel.h>
+#include <linux/percpu.h>
+#include <linux/slab.h>
+#include <linux/static_key.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/idr.h>
+#include <linux/irq.h>
+#include <linux/math64.h>
+#include <linux/log2.h>
+
+#include <trace/events/irq.h>
+
+#include "internals.h"
+
+DEFINE_STATIC_KEY_FALSE(irq_timing_enabled);
+
+DEFINE_PER_CPU(struct irq_timings, irq_timings);
+
+static DEFINE_IDR(irqt_stats);
+
+void irq_timings_enable(void)
+{
+	static_branch_enable(&irq_timing_enabled);
+}
+
+void irq_timings_disable(void)
+{
+	static_branch_disable(&irq_timing_enabled);
+}
+
+/*
+ * The main goal of this algorithm is to predict the next interrupt
+ * occurrence on the current CPU.
+ *
+ * Currently, the interrupt timings are stored in a circular array
+ * buffer every time there is an interrupt, as a tuple: the interrupt
+ * number and the associated timestamp when the event occurred <irq,
+ * timestamp>.
+ *
+ * For every interrupt occurring in a short period of time, we can
+ * measure the elapsed time between the occurrences for the same
+ * interrupt and we end up with a suite of intervals. The experience
+ * showed the interrupts are often coming following a periodic
+ * pattern.
+ *
+ * The objective of the algorithm is to find out this periodic pattern
+ * in a fastest way and use its period to predict the next irq event.
+ *
+ * When the next interrupt event is requested, we are in the situation
+ * where the interrupts are disabled and the circular buffer
+ * containing the timings is filled with the events which happened
+ * after the previous next-interrupt-event request.
+ *
+ * At this point, we read the circular buffer and we fill the irq
+ * related statistics structure. After this step, the circular array
+ * containing the timings is empty because all the values are
+ * dispatched in their corresponding buffers.
+ *
+ * Now for each interrupt, we can predict the next event by using the
+ * suffix array, log interval and exponential moving average
+ *
+ * 1. Suffix array
+ *
+ * Suffix array is an array of all the suffixes of a string. It is
+ * widely used as a data structure for compression, text search, ...
+ * For instance for the word 'banana', the suffixes will be: 'banana'
+ * 'anana' 'nana' 'ana' 'na' 'a'
+ *
+ * Usually, the suffix array is sorted but for our purpose it is
+ * not necessary and won't provide any improvement in the context of
+ * the solved problem where we clearly define the boundaries of the
+ * search by a max period and min period.
+ *
+ * The suffix array will build a suite of intervals of different
+ * length and will look for the repetition of each suite. If the suite
+ * is repeating then we have the period because it is the length of
+ * the suite whatever its position in the buffer.
+ *
+ * 2. Log interval
+ *
+ * We saw the irq timings allow to compute the interval of the
+ * occurrences for a specific interrupt. We can reasonably assume the
+ * longer is the interval, the higher is the error for the next event
+ * and we can consider storing those interval values into an array
+ * where each slot in the array correspond to an interval at the power
+ * of 2 of the index. For example, index 12 will contain values
+ * between 2^11 and 2^12.
+ *
+ * At the end we have an array of values where at each index defines a
+ * [2^index - 1, 2 ^ index] interval values allowing to store a large
+ * number of values inside a small array.
+ *
+ * For example, if we have the value 1123, then we store it at
+ * ilog2(1123) = 10 index value.
+ *
+ * Storing those value at the specific index is done by computing an
+ * exponential moving average for this specific slot. For instance,
+ * for values 1800, 1123, 1453, ... fall under the same slot (10) and
+ * the exponential moving average is computed every time a new value
+ * is stored at this slot.
+ *
+ * 3. Exponential Moving Average
+ *
+ * The EMA is largely used to track a signal for stocks or as a low
+ * pass filter. The magic of the formula, is it is very simple and the
+ * reactivity of the average can be tuned with the factors called
+ * alpha.
+ *
+ * The higher the alphas are, the faster the average respond to the
+ * signal change. In our case, if a slot in the array is a big
+ * interval, we can have numbers with a big difference between
+ * them. The impact of those differences in the average computation
+ * can be tuned by changing the alpha value.
+ *
+ *
+ *  -- The algorithm --
+ *
+ * We saw the different processing above, now let's see how they are
+ * used together.
+ *
+ * For each interrupt:
+ *	For each interval:
+ *		Compute the index = ilog2(interval)
+ *		Compute a new_ema(buffer[index], interval)
+ *		Store the index in a circular buffer
+ *
+ *	Compute the suffix array of the indexes
+ *
+ *	For each suffix:
+ *		If the suffix is reverse-found 3 times
+ *			Return suffix
+ *
+ *	Return Not found
+ *
+ * However we can not have endless suffix array to be build, it won't
+ * make sense and it will add an extra overhead, so we can restrict
+ * this to a maximum suffix length of 5 and a minimum suffix length of
+ * 2. The experience showed 5 is the majority of the maximum pattern
+ * period found for different devices.
+ *
+ * The result is a pattern finding less than 1us for an interrupt.
+ *
+ * Example based on real values:
+ *
+ * Example 1 : MMC write/read interrupt interval:
+ *
+ *	223947, 1240, 1384, 1386, 1386,
+ *	217416, 1236, 1384, 1386, 1387,
+ *	214719, 1241, 1386, 1387, 1384,
+ *	213696, 1234, 1384, 1386, 1388,
+ *	219904, 1240, 1385, 1389, 1385,
+ *	212240, 1240, 1386, 1386, 1386,
+ *	214415, 1236, 1384, 1386, 1387,
+ *	214276, 1234, 1384, 1388, ?
+ *
+ * For each element, apply ilog2(value)
+ *
+ *	15, 8, 8, 8, 8,
+ *	15, 8, 8, 8, 8,
+ *	15, 8, 8, 8, 8,
+ *	15, 8, 8, 8, 8,
+ *	15, 8, 8, 8, 8,
+ *	15, 8, 8, 8, 8,
+ *	15, 8, 8, 8, 8,
+ *	15, 8, 8, 8, ?
+ *
+ * Max period of 5, we take the last (max_period * 3) 15 elements as
+ * we can be confident if the pattern repeats itself three times it is
+ * a repeating pattern.
+ *
+ *	             8,
+ *	15, 8, 8, 8, 8,
+ *	15, 8, 8, 8, 8,
+ *	15, 8, 8, 8, ?
+ *
+ * Suffixes are:
+ *
+ *  1) 8, 15, 8, 8, 8  <- max period
+ *  2) 8, 15, 8, 8
+ *  3) 8, 15, 8
+ *  4) 8, 15           <- min period
+ *
+ * From there we search the repeating pattern for each suffix.
+ *
+ * buffer: 8, 15, 8, 8, 8, 8, 15, 8, 8, 8, 8, 15, 8, 8, 8
+ *         |   |  |  |  |  |   |  |  |  |  |   |  |  |  |
+ *         8, 15, 8, 8, 8  |   |  |  |  |  |   |  |  |  |
+ *                         8, 15, 8, 8, 8  |   |  |  |  |
+ *                                         8, 15, 8, 8, 8
+ *
+ * When moving the suffix, we found exactly 3 matches.
+ *
+ * The first suffix with period 5 is repeating.
+ *
+ * The next event is (3 * max_period) % suffix_period
+ *
+ * In this example, the result 0, so the next event is suffix[0] => 8
+ *
+ * However, 8 is the index in the array of exponential moving average
+ * which was calculated on the fly when storing the values, so the
+ * interval is ema[8] = 1366
+ *
+ *
+ * Example 2:
+ *
+ *	4, 3, 5, 100,
+ *	3, 3, 5, 117,
+ *	4, 4, 5, 112,
+ *	4, 3, 4, 110,
+ *	3, 5, 3, 117,
+ *	4, 4, 5, 112,
+ *	4, 3, 4, 110,
+ *	3, 4, 5, 112,
+ *	4, 3, 4, 110
+ *
+ * ilog2
+ *
+ *	0, 0, 0, 4,
+ *	0, 0, 0, 4,
+ *	0, 0, 0, 4,
+ *	0, 0, 0, 4,
+ *	0, 0, 0, 4,
+ *	0, 0, 0, 4,
+ *	0, 0, 0, 4,
+ *	0, 0, 0, 4,
+ *	0, 0, 0, 4
+ *
+ * Max period 5:
+ *	   0, 0, 4,
+ *	0, 0, 0, 4,
+ *	0, 0, 0, 4,
+ *	0, 0, 0, 4
+ *
+ * Suffixes:
+ *
+ *  1) 0, 0, 4, 0, 0
+ *  2) 0, 0, 4, 0
+ *  3) 0, 0, 4
+ *  4) 0, 0
+ *
+ * buffer: 0, 0, 4, 0, 0, 0, 4, 0, 0, 0, 4, 0, 0, 0, 4
+ *         |  |  |  |  |  |  X
+ *         0, 0, 4, 0, 0, |  X
+ *                        0, 0
+ *
+ * buffer: 0, 0, 4, 0, 0, 0, 4, 0, 0, 0, 4, 0, 0, 0, 4
+ *         |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
+ *         0, 0, 4, 0, |  |  |  |  |  |  |  |  |  |  |
+ *                     0, 0, 4, 0, |  |  |  |  |  |  |
+ *                                 0, 0, 4, 0, |  |  |
+ *                                             0  0  4
+ *
+ * Pattern is found 3 times, the remaining is 1 which results from
+ * (max_period * 3) % suffix_period. This value is the index in the
+ * suffix arrays. The suffix array for a period 4 has the value 4
+ * at index 1.
+ */
+#define EMA_ALPHA_VAL		64
+#define EMA_ALPHA_SHIFT		7
+
+#define PREDICTION_PERIOD_MIN	3
+#define PREDICTION_PERIOD_MAX	5
+#define PREDICTION_FACTOR	4
+#define PREDICTION_MAX		10 /* 2 ^ PREDICTION_MAX useconds */
+#define PREDICTION_BUFFER_SIZE	16 /* slots for EMAs, hardly more than 16 */
+
+/*
+ * Number of elements in the circular buffer: If it happens it was
+ * flushed before, then the number of elements could be smaller than
+ * IRQ_TIMINGS_SIZE, so the count is used, otherwise the array size is
+ * used as we wrapped. The index begins from zero when we did not
+ * wrap. That could be done in a nicer way with the proper circular
+ * array structure type but with the cost of extra computation in the
+ * interrupt handler hot path. We choose efficiency.
+ */
+#define for_each_irqts(i, irqts)					\
+	for (i = irqts->count < IRQ_TIMINGS_SIZE ?			\
+		     0 : irqts->count & IRQ_TIMINGS_MASK,		\
+		     irqts->count = min(IRQ_TIMINGS_SIZE,		\
+					irqts->count);			\
+	     irqts->count > 0; irqts->count--,				\
+		     i = (i + 1) & IRQ_TIMINGS_MASK)
+
+struct irqt_stat {
+	u64	last_ts;
+	u64	ema_time[PREDICTION_BUFFER_SIZE];
+	int	timings[IRQ_TIMINGS_SIZE];
+	int	circ_timings[IRQ_TIMINGS_SIZE];
+	int	count;
+};
+
+/*
+ * Exponential moving average computation
+ */
+static u64 irq_timings_ema_new(u64 value, u64 ema_old)
+{
+	s64 diff;
+
+	if (unlikely(!ema_old))
+		return value;
+
+	diff = (value - ema_old) * EMA_ALPHA_VAL;
+	/*
+	 * We can use a s64 type variable to be added with the u64
+	 * ema_old variable as this one will never have its topmost
+	 * bit set, it will be always smaller than 2^63 nanosec
+	 * interrupt interval (292 years).
+	 */
+	return ema_old + (diff >> EMA_ALPHA_SHIFT);
+}
+
+static int irq_timings_next_event_index(int *buffer, size_t len, int period_max)
+{
+	int period;
+
+	/*
+	 * Move the beginning pointer to the end minus the max period x 3.
+	 * We are at the point we can begin searching the pattern
+	 */
+	buffer = &buffer[len - (period_max * 3)];
+
+	/* Adjust the length to the maximum allowed period x 3 */
+	len = period_max * 3;
+
+	/*
+	 * The buffer contains the suite of intervals, in a ilog2
+	 * basis, we are looking for a repetition. We point the
+	 * beginning of the search three times the length of the
+	 * period beginning at the end of the buffer. We do that for
+	 * each suffix.
+	 */
+	for (period = period_max; period >= PREDICTION_PERIOD_MIN; period--) {
+
+		/*
+		 * The first comparison always succeed because the
+		 * suffix is deduced from the first n-period bytes of
+		 * the buffer and we compare the initial suffix with
+		 * itself, so we can skip the first iteration.
+		 */
+		int idx = period;
+		size_t size = period;
+
+		/*
+		 * We look if the suite with period 'i' repeat
+		 * itself. If it is truncated at the end, as it
+		 * repeats we can use the period to find out the next
+		 * element with the modulo.
+		 */
+		while (!memcmp(buffer, &buffer[idx], size * sizeof(int))) {
+
+			/*
+			 * Move the index in a period basis
+			 */
+			idx += size;
+
+			/*
+			 * If this condition is reached, all previous
+			 * memcmp were successful, so the period is
+			 * found.
+			 */
+			if (idx == len)
+				return buffer[len % period];
+
+			/*
+			 * If the remaining elements to compare are
+			 * smaller than the period, readjust the size
+			 * of the comparison for the last iteration.
+			 */
+			if (len - idx < period)
+				size = len - idx;
+		}
+	}
+
+	return -1;
+}
+
+static u64 __irq_timings_next_event(struct irqt_stat *irqs, int irq, u64 now)
+{
+	int index, i, period_max, count, start, min = INT_MAX;
+
+	if ((now - irqs->last_ts) >= NSEC_PER_SEC) {
+		irqs->count = irqs->last_ts = 0;
+		return U64_MAX;
+	}
+
+	/*
+	 * As we want to find three times the repetition, we need a
+	 * number of intervals greater or equal to three times the
+	 * maximum period, otherwise we truncate the max period.
+	 */
+	period_max = irqs->count > (3 * PREDICTION_PERIOD_MAX) ?
+		PREDICTION_PERIOD_MAX : irqs->count / 3;
+
+	/*
+	 * If we don't have enough irq timings for this prediction,
+	 * just bail out.
+	 */
+	if (period_max <= PREDICTION_PERIOD_MIN)
+		return U64_MAX;
+
+	/*
+	 * 'count' will depends if the circular buffer wrapped or not
+	 */
+	count = irqs->count < IRQ_TIMINGS_SIZE ?
+		irqs->count : IRQ_TIMINGS_SIZE;
+
+	start = irqs->count < IRQ_TIMINGS_SIZE ?
+		0 : (irqs->count & IRQ_TIMINGS_MASK);
+
+	/*
+	 * Copy the content of the circular buffer into another buffer
+	 * in order to linearize the buffer instead of dealing with
+	 * wrapping indexes and shifted array which will be prone to
+	 * error and extremely difficult to debug.
+	 */
+	for (i = 0; i < count; i++) {
+		int index = (start + i) & IRQ_TIMINGS_MASK;
+
+		irqs->timings[i] = irqs->circ_timings[index];
+		min = min_t(int, irqs->timings[i], min);
+	}
+
+	index = irq_timings_next_event_index(irqs->timings, count, period_max);
+	if (index < 0)
+		return irqs->last_ts + irqs->ema_time[min];
+
+	return irqs->last_ts + irqs->ema_time[index];
+}
+
+static __always_inline int irq_timings_interval_index(u64 interval)
+{
+	/*
+	 * The PREDICTION_FACTOR increase the interval size for the
+	 * array of exponential average.
+	 */
+	u64 interval_us = (interval >> 10) / PREDICTION_FACTOR;
+
+	return likely(interval_us) ? ilog2(interval_us) : 0;
+}
+
+static __always_inline void __irq_timings_store(int irq, struct irqt_stat *irqs,
+						u64 interval)
+{
+	int index;
+
+	/*
+	 * Get the index in the ema table for this interrupt.
+	 */
+	index = irq_timings_interval_index(interval);
+
+	if (index > PREDICTION_BUFFER_SIZE - 1) {
+		irqs->count = 0;
+		return;
+	}
+
+	/*
+	 * Store the index as an element of the pattern in another
+	 * circular array.
+	 */
+	irqs->circ_timings[irqs->count & IRQ_TIMINGS_MASK] = index;
+
+	irqs->ema_time[index] = irq_timings_ema_new(interval,
+						    irqs->ema_time[index]);
+
+	irqs->count++;
+}
+
+static inline void irq_timings_store(int irq, struct irqt_stat *irqs, u64 ts)
+{
+	u64 old_ts = irqs->last_ts;
+	u64 interval;
+
+	/*
+	 * The timestamps are absolute time values, we need to compute
+	 * the timing interval between two interrupts.
+	 */
+	irqs->last_ts = ts;
+
+	/*
+	 * The interval type is u64 in order to deal with the same
+	 * type in our computation, that prevent mindfuck issues with
+	 * overflow, sign and division.
+	 */
+	interval = ts - old_ts;
+
+	/*
+	 * The interrupt triggered more than one second apart, that
+	 * ends the sequence as predictable for our purpose. In this
+	 * case, assume we have the beginning of a sequence and the
+	 * timestamp is the first value. As it is impossible to
+	 * predict anything at this point, return.
+	 *
+	 * Note the first timestamp of the sequence will always fall
+	 * in this test because the old_ts is zero. That is what we
+	 * want as we need another timestamp to compute an interval.
+	 */
+	if (interval >= NSEC_PER_SEC) {
+		irqs->count = 0;
+		return;
+	}
+
+	__irq_timings_store(irq, irqs, interval);
+}
+
+/**
+ * irq_timings_next_event - Return when the next event is supposed to arrive
+ *
+ * During the last busy cycle, the number of interrupts is incremented
+ * and stored in the irq_timings structure. This information is
+ * necessary to:
+ *
+ * - know if the index in the table wrapped up:
+ *
+ *      If more than the array size interrupts happened during the
+ *      last busy/idle cycle, the index wrapped up and we have to
+ *      begin with the next element in the array which is the last one
+ *      in the sequence, otherwise it is at the index 0.
+ *
+ * - have an indication of the interrupts activity on this CPU
+ *   (eg. irq/sec)
+ *
+ * The values are 'consumed' after inserting in the statistical model,
+ * thus the count is reinitialized.
+ *
+ * The array of values **must** be browsed in the time direction, the
+ * timestamp must increase between an element and the next one.
+ *
+ * Returns a nanosec time based estimation of the earliest interrupt,
+ * U64_MAX otherwise.
+ */
+u64 irq_timings_next_event(u64 now)
+{
+	struct irq_timings *irqts = this_cpu_ptr(&irq_timings);
+	struct irqt_stat *irqs;
+	struct irqt_stat __percpu *s;
+	u64 ts, next_evt = U64_MAX;
+	int i, irq = 0;
+
+	/*
+	 * This function must be called with the local irq disabled in
+	 * order to prevent the timings circular buffer to be updated
+	 * while we are reading it.
+	 */
+	lockdep_assert_irqs_disabled();
+
+	if (!irqts->count)
+		return next_evt;
+
+	/*
+	 * Number of elements in the circular buffer: If it happens it
+	 * was flushed before, then the number of elements could be
+	 * smaller than IRQ_TIMINGS_SIZE, so the count is used,
+	 * otherwise the array size is used as we wrapped. The index
+	 * begins from zero when we did not wrap. That could be done
+	 * in a nicer way with the proper circular array structure
+	 * type but with the cost of extra computation in the
+	 * interrupt handler hot path. We choose efficiency.
+	 *
+	 * Inject measured irq/timestamp to the pattern prediction
+	 * model while decrementing the counter because we consume the
+	 * data from our circular buffer.
+	 */
+	for_each_irqts(i, irqts) {
+		irq = irq_timing_decode(irqts->values[i], &ts);
+		s = idr_find(&irqt_stats, irq);
+		if (s)
+			irq_timings_store(irq, this_cpu_ptr(s), ts);
+	}
+
+	/*
+	 * Look in the list of interrupts' statistics, the earliest
+	 * next event.
+	 */
+	idr_for_each_entry(&irqt_stats, s, i) {
+
+		irqs = this_cpu_ptr(s);
+
+		ts = __irq_timings_next_event(irqs, i, now);
+		if (ts <= now)
+			return now;
+
+		if (ts < next_evt)
+			next_evt = ts;
+	}
+
+	return next_evt;
+}
+
+void irq_timings_free(int irq)
+{
+	struct irqt_stat __percpu *s;
+
+	s = idr_find(&irqt_stats, irq);
+	if (s) {
+		free_percpu(s);
+		idr_remove(&irqt_stats, irq);
+	}
+}
+
+int irq_timings_alloc(int irq)
+{
+	struct irqt_stat __percpu *s;
+	int id;
+
+	/*
+	 * Some platforms can have the same private interrupt per cpu,
+	 * so this function may be called several times with the
+	 * same interrupt number. Just bail out in case the per cpu
+	 * stat structure is already allocated.
+	 */
+	s = idr_find(&irqt_stats, irq);
+	if (s)
+		return 0;
+
+	s = alloc_percpu(*s);
+	if (!s)
+		return -ENOMEM;
+
+	idr_preload(GFP_KERNEL);
+	id = idr_alloc(&irqt_stats, s, irq, irq + 1, GFP_NOWAIT);
+	idr_preload_end();
+
+	if (id < 0) {
+		free_percpu(s);
+		return id;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_TEST_IRQ_TIMINGS
+struct timings_intervals {
+	u64 *intervals;
+	size_t count;
+};
+
+/*
+ * Intervals are given in nanosecond base
+ */
+static u64 intervals0[] __initdata = {
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000, 500000,
+	10000, 50000, 200000,
+};
+
+static u64 intervals1[] __initdata = {
+	223947000, 1240000, 1384000, 1386000, 1386000,
+	217416000, 1236000, 1384000, 1386000, 1387000,
+	214719000, 1241000, 1386000, 1387000, 1384000,
+	213696000, 1234000, 1384000, 1386000, 1388000,
+	219904000, 1240000, 1385000, 1389000, 1385000,
+	212240000, 1240000, 1386000, 1386000, 1386000,
+	214415000, 1236000, 1384000, 1386000, 1387000,
+	214276000, 1234000,
+};
+
+static u64 intervals2[] __initdata = {
+	4000, 3000, 5000, 100000,
+	3000, 3000, 5000, 117000,
+	4000, 4000, 5000, 112000,
+	4000, 3000, 4000, 110000,
+	3000, 5000, 3000, 117000,
+	4000, 4000, 5000, 112000,
+	4000, 3000, 4000, 110000,
+	3000, 4000, 5000, 112000,
+	4000,
+};
+
+static u64 intervals3[] __initdata = {
+	1385000, 212240000, 1240000,
+	1386000, 214415000, 1236000,
+	1384000, 214276000, 1234000,
+	1386000, 214415000, 1236000,
+	1385000, 212240000, 1240000,
+	1386000, 214415000, 1236000,
+	1384000, 214276000, 1234000,
+	1386000, 214415000, 1236000,
+	1385000, 212240000, 1240000,
+};
+
+static u64 intervals4[] __initdata = {
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000, 50000, 10000, 50000,
+	10000,
+};
+
+static struct timings_intervals tis[] __initdata = {
+	{ intervals0, ARRAY_SIZE(intervals0) },
+	{ intervals1, ARRAY_SIZE(intervals1) },
+	{ intervals2, ARRAY_SIZE(intervals2) },
+	{ intervals3, ARRAY_SIZE(intervals3) },
+	{ intervals4, ARRAY_SIZE(intervals4) },
+};
+
+static int __init irq_timings_test_next_index(struct timings_intervals *ti)
+{
+	int _buffer[IRQ_TIMINGS_SIZE];
+	int buffer[IRQ_TIMINGS_SIZE];
+	int index, start, i, count, period_max;
+
+	count = ti->count - 1;
+
+	period_max = count > (3 * PREDICTION_PERIOD_MAX) ?
+		PREDICTION_PERIOD_MAX : count / 3;
+
+	/*
+	 * Inject all values except the last one which will be used
+	 * to compare with the next index result.
+	 */
+	pr_debug("index suite: ");
+
+	for (i = 0; i < count; i++) {
+		index = irq_timings_interval_index(ti->intervals[i]);
+		_buffer[i & IRQ_TIMINGS_MASK] = index;
+		pr_cont("%d ", index);
+	}
+
+	start = count < IRQ_TIMINGS_SIZE ? 0 :
+		count & IRQ_TIMINGS_MASK;
+
+	count = min_t(int, count, IRQ_TIMINGS_SIZE);
+
+	for (i = 0; i < count; i++) {
+		int index = (start + i) & IRQ_TIMINGS_MASK;
+		buffer[i] = _buffer[index];
+	}
+
+	index = irq_timings_next_event_index(buffer, count, period_max);
+	i = irq_timings_interval_index(ti->intervals[ti->count - 1]);
+
+	if (index != i) {
+		pr_err("Expected (%d) and computed (%d) next indexes differ\n",
+		       i, index);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int __init irq_timings_next_index_selftest(void)
+{
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(tis); i++) {
+
+		pr_info("---> Injecting intervals number #%d (count=%zd)\n",
+			i, tis[i].count);
+
+		ret = irq_timings_test_next_index(&tis[i]);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static int __init irq_timings_test_irqs(struct timings_intervals *ti)
+{
+	struct irqt_stat __percpu *s;
+	struct irqt_stat *irqs;
+	int i, index, ret, irq = 0xACE5;
+
+	ret = irq_timings_alloc(irq);
+	if (ret) {
+		pr_err("Failed to allocate irq timings\n");
+		return ret;
+	}
+
+	s = idr_find(&irqt_stats, irq);
+	if (!s) {
+		ret = -EIDRM;
+		goto out;
+	}
+
+	irqs = this_cpu_ptr(s);
+
+	for (i = 0; i < ti->count; i++) {
+
+		index = irq_timings_interval_index(ti->intervals[i]);
+		pr_debug("%d: interval=%llu ema_index=%d\n",
+			 i, ti->intervals[i], index);
+
+		__irq_timings_store(irq, irqs, ti->intervals[i]);
+		if (irqs->circ_timings[i & IRQ_TIMINGS_MASK] != index) {
+			ret = -EBADSLT;
+			pr_err("Failed to store in the circular buffer\n");
+			goto out;
+		}
+	}
+
+	if (irqs->count != ti->count) {
+		ret = -ERANGE;
+		pr_err("Count differs\n");
+		goto out;
+	}
+
+	ret = 0;
+out:
+	irq_timings_free(irq);
+
+	return ret;
+}
+
+static int __init irq_timings_irqs_selftest(void)
+{
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(tis); i++) {
+		pr_info("---> Injecting intervals number #%d (count=%zd)\n",
+			i, tis[i].count);
+		ret = irq_timings_test_irqs(&tis[i]);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static int __init irq_timings_test_irqts(struct irq_timings *irqts,
+					 unsigned count)
+{
+	int start = count >= IRQ_TIMINGS_SIZE ? count - IRQ_TIMINGS_SIZE : 0;
+	int i, irq, oirq = 0xBEEF;
+	u64 ots = 0xDEAD, ts;
+
+	/*
+	 * Fill the circular buffer by using the dedicated function.
+	 */
+	for (i = 0; i < count; i++) {
+		pr_debug("%d: index=%d, ts=%llX irq=%X\n",
+			 i, i & IRQ_TIMINGS_MASK, ots + i, oirq + i);
+
+		irq_timings_push(ots + i, oirq + i);
+	}
+
+	/*
+	 * Compute the first elements values after the index wrapped
+	 * up or not.
+	 */
+	ots += start;
+	oirq += start;
+
+	/*
+	 * Test the circular buffer count is correct.
+	 */
+	pr_debug("---> Checking timings array count (%d) is right\n", count);
+	if (WARN_ON(irqts->count != count))
+		return -EINVAL;
+
+	/*
+	 * Test the macro allowing to browse all the irqts.
+	 */
+	pr_debug("---> Checking the for_each_irqts() macro\n");
+	for_each_irqts(i, irqts) {
+
+		irq = irq_timing_decode(irqts->values[i], &ts);
+
+		pr_debug("index=%d, ts=%llX / %llX, irq=%X / %X\n",
+			 i, ts, ots, irq, oirq);
+
+		if (WARN_ON(ts != ots || irq != oirq))
+			return -EINVAL;
+
+		ots++; oirq++;
+	}
+
+	/*
+	 * The circular buffer should have be flushed when browsed
+	 * with for_each_irqts
+	 */
+	pr_debug("---> Checking timings array is empty after browsing it\n");
+	if (WARN_ON(irqts->count))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int __init irq_timings_irqts_selftest(void)
+{
+	struct irq_timings *irqts = this_cpu_ptr(&irq_timings);
+	int i, ret;
+
+	/*
+	 * Test the circular buffer with different number of
+	 * elements. The purpose is to test at the limits (empty, half
+	 * full, full, wrapped with the cursor at the boundaries,
+	 * wrapped several times, etc ...
+	 */
+	int count[] = { 0,
+			IRQ_TIMINGS_SIZE >> 1,
+			IRQ_TIMINGS_SIZE,
+			IRQ_TIMINGS_SIZE + (IRQ_TIMINGS_SIZE >> 1),
+			2 * IRQ_TIMINGS_SIZE,
+			(2 * IRQ_TIMINGS_SIZE) + 3,
+	};
+
+	for (i = 0; i < ARRAY_SIZE(count); i++) {
+
+		pr_info("---> Checking the timings with %d/%d values\n",
+			count[i], IRQ_TIMINGS_SIZE);
+
+		ret = irq_timings_test_irqts(irqts, count[i]);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static int __init irq_timings_selftest(void)
+{
+	int ret;
+
+	pr_info("------------------- selftest start -----------------\n");
+
+	/*
+	 * At this point, we don't except any subsystem to use the irq
+	 * timings but us, so it should not be enabled.
+	 */
+	if (static_branch_unlikely(&irq_timing_enabled)) {
+		pr_warn("irq timings already initialized, skipping selftest\n");
+		return 0;
+	}
+
+	ret = irq_timings_irqts_selftest();
+	if (ret)
+		goto out;
+
+	ret = irq_timings_irqs_selftest();
+	if (ret)
+		goto out;
+
+	ret = irq_timings_next_index_selftest();
+out:
+	pr_info("---------- selftest end with %s -----------\n",
+		ret ? "failure" : "success");
+
+	return ret;
+}
+early_initcall(irq_timings_selftest);
+#endif
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
new file mode 100644
index 000000000..7afa40fe5
--- /dev/null
+++ b/kernel/irq_work.c
@@ -0,0 +1,317 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2010 Red Hat, Inc., Peter Zijlstra
+ *
+ * Provides a framework for enqueueing and running callbacks from hardirq
+ * context. The enqueueing is NMI-safe.
+ */
+
+#include <linux/bug.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/irq_work.h>
+#include <linux/percpu.h>
+#include <linux/hardirq.h>
+#include <linux/irqflags.h>
+#include <linux/sched.h>
+#include <linux/tick.h>
+#include <linux/cpu.h>
+#include <linux/notifier.h>
+#include <linux/smp.h>
+#include <linux/smpboot.h>
+#include <asm/processor.h>
+#include <linux/kasan.h>
+
+static DEFINE_PER_CPU(struct llist_head, raised_list);
+static DEFINE_PER_CPU(struct llist_head, lazy_list);
+static DEFINE_PER_CPU(struct task_struct *, irq_workd);
+
+static void wake_irq_workd(void)
+{
+	struct task_struct *tsk = __this_cpu_read(irq_workd);
+
+	if (!llist_empty(this_cpu_ptr(&lazy_list)) && tsk)
+		wake_up_process(tsk);
+}
+
+#ifdef CONFIG_SMP
+static void irq_work_wake(struct irq_work *entry)
+{
+	wake_irq_workd();
+}
+
+static DEFINE_PER_CPU(struct irq_work, irq_work_wakeup) =
+	IRQ_WORK_INIT_HARD(irq_work_wake);
+#endif
+
+static int irq_workd_should_run(unsigned int cpu)
+{
+	return !llist_empty(this_cpu_ptr(&lazy_list));
+}
+
+/*
+ * Claim the entry so that no one else will poke at it.
+ */
+static bool irq_work_claim(struct irq_work *work)
+{
+	int oflags;
+
+	oflags = atomic_fetch_or(IRQ_WORK_CLAIMED | CSD_TYPE_IRQ_WORK, &work->node.a_flags);
+	/*
+	 * If the work is already pending, no need to raise the IPI.
+	 * The pairing smp_mb() in irq_work_single() makes sure
+	 * everything we did before is visible.
+	 */
+	if (oflags & IRQ_WORK_PENDING)
+		return false;
+	return true;
+}
+
+void __weak arch_irq_work_raise(void)
+{
+	/*
+	 * Lame architectures will get the timer tick callback
+	 */
+}
+
+/* Enqueue on current CPU, work must already be claimed and preempt disabled */
+static void __irq_work_queue_local(struct irq_work *work)
+{
+	struct llist_head *list;
+	bool rt_lazy_work = false;
+	bool lazy_work = false;
+	int work_flags;
+
+	work_flags = atomic_read(&work->node.a_flags);
+	if (work_flags & IRQ_WORK_LAZY)
+		lazy_work = true;
+	else if (IS_ENABLED(CONFIG_PREEMPT_RT) &&
+		 !(work_flags & IRQ_WORK_HARD_IRQ))
+		rt_lazy_work = true;
+
+	if (lazy_work || rt_lazy_work)
+		list = this_cpu_ptr(&lazy_list);
+	else
+		list = this_cpu_ptr(&raised_list);
+
+	if (!llist_add(&work->node.llist, list))
+		return;
+
+	/* If the work is "lazy", handle it from next tick if any */
+	if (!lazy_work || tick_nohz_tick_stopped())
+		arch_irq_work_raise();
+}
+
+/* Enqueue the irq work @work on the current CPU */
+bool irq_work_queue(struct irq_work *work)
+{
+	/* Only queue if not already pending */
+	if (!irq_work_claim(work))
+		return false;
+
+	/* Queue the entry and raise the IPI if needed. */
+	preempt_disable();
+	__irq_work_queue_local(work);
+	preempt_enable();
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(irq_work_queue);
+
+/*
+ * Enqueue the irq_work @work on @cpu unless it's already pending
+ * somewhere.
+ *
+ * Can be re-enqueued while the callback is still in progress.
+ */
+bool irq_work_queue_on(struct irq_work *work, int cpu)
+{
+#ifndef CONFIG_SMP
+	return irq_work_queue(work);
+
+#else /* CONFIG_SMP: */
+	/* All work should have been flushed before going offline */
+	WARN_ON_ONCE(cpu_is_offline(cpu));
+
+	/* Only queue if not already pending */
+	if (!irq_work_claim(work))
+		return false;
+
+	kasan_record_aux_stack_noalloc(work);
+
+	preempt_disable();
+	if (cpu != smp_processor_id()) {
+		/* Arch remote IPI send/receive backend aren't NMI safe */
+		WARN_ON_ONCE(in_nmi());
+
+		/*
+		 * On PREEMPT_RT the items which are not marked as
+		 * IRQ_WORK_HARD_IRQ are added to the lazy list and a HARD work
+		 * item is used on the remote CPU to wake the thread.
+		 */
+		if (IS_ENABLED(CONFIG_PREEMPT_RT) &&
+		    !(atomic_read(&work->node.a_flags) & IRQ_WORK_HARD_IRQ)) {
+
+			if (!llist_add(&work->node.llist, &per_cpu(lazy_list, cpu)))
+				goto out;
+
+			work = &per_cpu(irq_work_wakeup, cpu);
+			if (!irq_work_claim(work))
+				goto out;
+		}
+
+		__smp_call_single_queue(cpu, &work->node.llist);
+	} else {
+		__irq_work_queue_local(work);
+	}
+out:
+	preempt_enable();
+
+	return true;
+#endif /* CONFIG_SMP */
+}
+
+bool irq_work_needs_cpu(void)
+{
+	struct llist_head *raised, *lazy;
+
+	raised = this_cpu_ptr(&raised_list);
+	lazy = this_cpu_ptr(&lazy_list);
+
+	if (llist_empty(raised) || arch_irq_work_has_interrupt())
+		if (llist_empty(lazy))
+			return false;
+
+	/* All work should have been flushed before going offline */
+	WARN_ON_ONCE(cpu_is_offline(smp_processor_id()));
+
+	return true;
+}
+
+void irq_work_single(void *arg)
+{
+	struct irq_work *work = arg;
+	int flags;
+
+	/*
+	 * Clear the PENDING bit, after this point the @work can be re-used.
+	 * The PENDING bit acts as a lock, and we own it, so we can clear it
+	 * without atomic ops.
+	 */
+	flags = atomic_read(&work->node.a_flags);
+	flags &= ~IRQ_WORK_PENDING;
+	atomic_set(&work->node.a_flags, flags);
+
+	/*
+	 * See irq_work_claim().
+	 */
+	smp_mb();
+
+	lockdep_irq_work_enter(flags);
+	work->func(work);
+	lockdep_irq_work_exit(flags);
+
+	/*
+	 * Clear the BUSY bit, if set, and return to the free state if no-one
+	 * else claimed it meanwhile.
+	 */
+	(void)atomic_cmpxchg(&work->node.a_flags, flags, flags & ~IRQ_WORK_BUSY);
+
+	if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) ||
+	    !arch_irq_work_has_interrupt())
+		rcuwait_wake_up(&work->irqwait);
+}
+
+static void irq_work_run_list(struct llist_head *list)
+{
+	struct irq_work *work, *tmp;
+	struct llist_node *llnode;
+
+	/*
+	 * On PREEMPT_RT IRQ-work which is not marked as HARD will be processed
+	 * in a per-CPU thread in preemptible context. Only the items which are
+	 * marked as IRQ_WORK_HARD_IRQ will be processed in hardirq context.
+	 */
+	BUG_ON(!irqs_disabled() && !IS_ENABLED(CONFIG_PREEMPT_RT));
+
+	if (llist_empty(list))
+		return;
+
+	llnode = llist_del_all(list);
+	llist_for_each_entry_safe(work, tmp, llnode, node.llist)
+		irq_work_single(work);
+}
+
+/*
+ * hotplug calls this through:
+ *  hotplug_cfd() -> flush_smp_call_function_queue()
+ */
+void irq_work_run(void)
+{
+	irq_work_run_list(this_cpu_ptr(&raised_list));
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		irq_work_run_list(this_cpu_ptr(&lazy_list));
+	else
+		wake_irq_workd();
+}
+EXPORT_SYMBOL_GPL(irq_work_run);
+
+void irq_work_tick(void)
+{
+	struct llist_head *raised = this_cpu_ptr(&raised_list);
+
+	if (!llist_empty(raised) && !arch_irq_work_has_interrupt())
+		irq_work_run_list(raised);
+
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		irq_work_run_list(this_cpu_ptr(&lazy_list));
+	else
+		wake_irq_workd();
+}
+
+/*
+ * Synchronize against the irq_work @entry, ensures the entry is not
+ * currently in use.
+ */
+void irq_work_sync(struct irq_work *work)
+{
+	lockdep_assert_irqs_enabled();
+	might_sleep();
+
+	if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) ||
+	    !arch_irq_work_has_interrupt()) {
+		rcuwait_wait_event(&work->irqwait, !irq_work_is_busy(work),
+				   TASK_UNINTERRUPTIBLE);
+		return;
+	}
+
+	while (irq_work_is_busy(work))
+		cpu_relax();
+}
+EXPORT_SYMBOL_GPL(irq_work_sync);
+
+static void run_irq_workd(unsigned int cpu)
+{
+	irq_work_run_list(this_cpu_ptr(&lazy_list));
+}
+
+static void irq_workd_setup(unsigned int cpu)
+{
+	sched_set_fifo_low(current);
+}
+
+static struct smp_hotplug_thread irqwork_threads = {
+	.store                  = &irq_workd,
+	.setup			= irq_workd_setup,
+	.thread_should_run      = irq_workd_should_run,
+	.thread_fn              = run_irq_workd,
+	.thread_comm            = "irq_work/%u",
+};
+
+static __init int irq_work_init_threads(void)
+{
+	if (IS_ENABLED(CONFIG_PREEMPT_RT))
+		BUG_ON(smpboot_register_percpu_thread(&irqwork_threads));
+	return 0;
+}
+early_initcall(irq_work_init_threads);
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
new file mode 100644
index 000000000..714ac4c3b
--- /dev/null
+++ b/kernel/jump_label.c
@@ -0,0 +1,839 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * jump label support
+ *
+ * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
+ * Copyright (C) 2011 Peter Zijlstra
+ *
+ */
+#include <linux/memory.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include <linux/err.h>
+#include <linux/static_key.h>
+#include <linux/jump_label_ratelimit.h>
+#include <linux/bug.h>
+#include <linux/cpu.h>
+#include <asm/sections.h>
+
+/* mutex to protect coming/going of the jump_label table */
+static DEFINE_MUTEX(jump_label_mutex);
+
+void jump_label_lock(void)
+{
+	mutex_lock(&jump_label_mutex);
+}
+
+void jump_label_unlock(void)
+{
+	mutex_unlock(&jump_label_mutex);
+}
+
+static int jump_label_cmp(const void *a, const void *b)
+{
+	const struct jump_entry *jea = a;
+	const struct jump_entry *jeb = b;
+
+	/*
+	 * Entrires are sorted by key.
+	 */
+	if (jump_entry_key(jea) < jump_entry_key(jeb))
+		return -1;
+
+	if (jump_entry_key(jea) > jump_entry_key(jeb))
+		return 1;
+
+	/*
+	 * In the batching mode, entries should also be sorted by the code
+	 * inside the already sorted list of entries, enabling a bsearch in
+	 * the vector.
+	 */
+	if (jump_entry_code(jea) < jump_entry_code(jeb))
+		return -1;
+
+	if (jump_entry_code(jea) > jump_entry_code(jeb))
+		return 1;
+
+	return 0;
+}
+
+static void jump_label_swap(void *a, void *b, int size)
+{
+	long delta = (unsigned long)a - (unsigned long)b;
+	struct jump_entry *jea = a;
+	struct jump_entry *jeb = b;
+	struct jump_entry tmp = *jea;
+
+	jea->code	= jeb->code - delta;
+	jea->target	= jeb->target - delta;
+	jea->key	= jeb->key - delta;
+
+	jeb->code	= tmp.code + delta;
+	jeb->target	= tmp.target + delta;
+	jeb->key	= tmp.key + delta;
+}
+
+static void
+jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)
+{
+	unsigned long size;
+	void *swapfn = NULL;
+
+	if (IS_ENABLED(CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE))
+		swapfn = jump_label_swap;
+
+	size = (((unsigned long)stop - (unsigned long)start)
+					/ sizeof(struct jump_entry));
+	sort(start, size, sizeof(struct jump_entry), jump_label_cmp, swapfn);
+}
+
+static void jump_label_update(struct static_key *key);
+
+/*
+ * There are similar definitions for the !CONFIG_JUMP_LABEL case in jump_label.h.
+ * The use of 'atomic_read()' requires atomic.h and its problematic for some
+ * kernel headers such as kernel.h and others. Since static_key_count() is not
+ * used in the branch statements as it is for the !CONFIG_JUMP_LABEL case its ok
+ * to have it be a function here. Similarly, for 'static_key_enable()' and
+ * 'static_key_disable()', which require bug.h. This should allow jump_label.h
+ * to be included from most/all places for CONFIG_JUMP_LABEL.
+ */
+int static_key_count(struct static_key *key)
+{
+	/*
+	 * -1 means the first static_key_slow_inc() is in progress.
+	 *  static_key_enabled() must return true, so return 1 here.
+	 */
+	int n = atomic_read(&key->enabled);
+
+	return n >= 0 ? n : 1;
+}
+EXPORT_SYMBOL_GPL(static_key_count);
+
+void static_key_slow_inc_cpuslocked(struct static_key *key)
+{
+	int v, v1;
+
+	STATIC_KEY_CHECK_USE(key);
+	lockdep_assert_cpus_held();
+
+	/*
+	 * Careful if we get concurrent static_key_slow_inc() calls;
+	 * later calls must wait for the first one to _finish_ the
+	 * jump_label_update() process.  At the same time, however,
+	 * the jump_label_update() call below wants to see
+	 * static_key_enabled(&key) for jumps to be updated properly.
+	 *
+	 * So give a special meaning to negative key->enabled: it sends
+	 * static_key_slow_inc() down the slow path, and it is non-zero
+	 * so it counts as "enabled" in jump_label_update().  Note that
+	 * atomic_inc_unless_negative() checks >= 0, so roll our own.
+	 */
+	for (v = atomic_read(&key->enabled); v > 0; v = v1) {
+		v1 = atomic_cmpxchg(&key->enabled, v, v + 1);
+		if (likely(v1 == v))
+			return;
+	}
+
+	jump_label_lock();
+	if (atomic_read(&key->enabled) == 0) {
+		atomic_set(&key->enabled, -1);
+		jump_label_update(key);
+		/*
+		 * Ensure that if the above cmpxchg loop observes our positive
+		 * value, it must also observe all the text changes.
+		 */
+		atomic_set_release(&key->enabled, 1);
+	} else {
+		atomic_inc(&key->enabled);
+	}
+	jump_label_unlock();
+}
+
+void static_key_slow_inc(struct static_key *key)
+{
+	cpus_read_lock();
+	static_key_slow_inc_cpuslocked(key);
+	cpus_read_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_slow_inc);
+
+void static_key_enable_cpuslocked(struct static_key *key)
+{
+	STATIC_KEY_CHECK_USE(key);
+	lockdep_assert_cpus_held();
+
+	if (atomic_read(&key->enabled) > 0) {
+		WARN_ON_ONCE(atomic_read(&key->enabled) != 1);
+		return;
+	}
+
+	jump_label_lock();
+	if (atomic_read(&key->enabled) == 0) {
+		atomic_set(&key->enabled, -1);
+		jump_label_update(key);
+		/*
+		 * See static_key_slow_inc().
+		 */
+		atomic_set_release(&key->enabled, 1);
+	}
+	jump_label_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_enable_cpuslocked);
+
+void static_key_enable(struct static_key *key)
+{
+	cpus_read_lock();
+	static_key_enable_cpuslocked(key);
+	cpus_read_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_enable);
+
+void static_key_disable_cpuslocked(struct static_key *key)
+{
+	STATIC_KEY_CHECK_USE(key);
+	lockdep_assert_cpus_held();
+
+	if (atomic_read(&key->enabled) != 1) {
+		WARN_ON_ONCE(atomic_read(&key->enabled) != 0);
+		return;
+	}
+
+	jump_label_lock();
+	if (atomic_cmpxchg(&key->enabled, 1, 0))
+		jump_label_update(key);
+	jump_label_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_disable_cpuslocked);
+
+void static_key_disable(struct static_key *key)
+{
+	cpus_read_lock();
+	static_key_disable_cpuslocked(key);
+	cpus_read_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_disable);
+
+static bool static_key_slow_try_dec(struct static_key *key)
+{
+	int val;
+
+	val = atomic_fetch_add_unless(&key->enabled, -1, 1);
+	if (val == 1)
+		return false;
+
+	/*
+	 * The negative count check is valid even when a negative
+	 * key->enabled is in use by static_key_slow_inc(); a
+	 * __static_key_slow_dec() before the first static_key_slow_inc()
+	 * returns is unbalanced, because all other static_key_slow_inc()
+	 * instances block while the update is in progress.
+	 */
+	WARN(val < 0, "jump label: negative count!\n");
+	return true;
+}
+
+static void __static_key_slow_dec_cpuslocked(struct static_key *key)
+{
+	lockdep_assert_cpus_held();
+
+	if (static_key_slow_try_dec(key))
+		return;
+
+	jump_label_lock();
+	if (atomic_dec_and_test(&key->enabled))
+		jump_label_update(key);
+	jump_label_unlock();
+}
+
+static void __static_key_slow_dec(struct static_key *key)
+{
+	cpus_read_lock();
+	__static_key_slow_dec_cpuslocked(key);
+	cpus_read_unlock();
+}
+
+void jump_label_update_timeout(struct work_struct *work)
+{
+	struct static_key_deferred *key =
+		container_of(work, struct static_key_deferred, work.work);
+	__static_key_slow_dec(&key->key);
+}
+EXPORT_SYMBOL_GPL(jump_label_update_timeout);
+
+void static_key_slow_dec(struct static_key *key)
+{
+	STATIC_KEY_CHECK_USE(key);
+	__static_key_slow_dec(key);
+}
+EXPORT_SYMBOL_GPL(static_key_slow_dec);
+
+void static_key_slow_dec_cpuslocked(struct static_key *key)
+{
+	STATIC_KEY_CHECK_USE(key);
+	__static_key_slow_dec_cpuslocked(key);
+}
+
+void __static_key_slow_dec_deferred(struct static_key *key,
+				    struct delayed_work *work,
+				    unsigned long timeout)
+{
+	STATIC_KEY_CHECK_USE(key);
+
+	if (static_key_slow_try_dec(key))
+		return;
+
+	schedule_delayed_work(work, timeout);
+}
+EXPORT_SYMBOL_GPL(__static_key_slow_dec_deferred);
+
+void __static_key_deferred_flush(void *key, struct delayed_work *work)
+{
+	STATIC_KEY_CHECK_USE(key);
+	flush_delayed_work(work);
+}
+EXPORT_SYMBOL_GPL(__static_key_deferred_flush);
+
+void jump_label_rate_limit(struct static_key_deferred *key,
+		unsigned long rl)
+{
+	STATIC_KEY_CHECK_USE(key);
+	key->timeout = rl;
+	INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);
+}
+EXPORT_SYMBOL_GPL(jump_label_rate_limit);
+
+static int addr_conflict(struct jump_entry *entry, void *start, void *end)
+{
+	if (jump_entry_code(entry) <= (unsigned long)end &&
+	    jump_entry_code(entry) + jump_entry_size(entry) > (unsigned long)start)
+		return 1;
+
+	return 0;
+}
+
+static int __jump_label_text_reserved(struct jump_entry *iter_start,
+		struct jump_entry *iter_stop, void *start, void *end, bool init)
+{
+	struct jump_entry *iter;
+
+	iter = iter_start;
+	while (iter < iter_stop) {
+		if (init || !jump_entry_is_init(iter)) {
+			if (addr_conflict(iter, start, end))
+				return 1;
+		}
+		iter++;
+	}
+
+	return 0;
+}
+
+#ifndef arch_jump_label_transform_static
+static void arch_jump_label_transform_static(struct jump_entry *entry,
+					     enum jump_label_type type)
+{
+	/* nothing to do on most architectures */
+}
+#endif
+
+static inline struct jump_entry *static_key_entries(struct static_key *key)
+{
+	WARN_ON_ONCE(key->type & JUMP_TYPE_LINKED);
+	return (struct jump_entry *)(key->type & ~JUMP_TYPE_MASK);
+}
+
+static inline bool static_key_type(struct static_key *key)
+{
+	return key->type & JUMP_TYPE_TRUE;
+}
+
+static inline bool static_key_linked(struct static_key *key)
+{
+	return key->type & JUMP_TYPE_LINKED;
+}
+
+static inline void static_key_clear_linked(struct static_key *key)
+{
+	key->type &= ~JUMP_TYPE_LINKED;
+}
+
+static inline void static_key_set_linked(struct static_key *key)
+{
+	key->type |= JUMP_TYPE_LINKED;
+}
+
+/***
+ * A 'struct static_key' uses a union such that it either points directly
+ * to a table of 'struct jump_entry' or to a linked list of modules which in
+ * turn point to 'struct jump_entry' tables.
+ *
+ * The two lower bits of the pointer are used to keep track of which pointer
+ * type is in use and to store the initial branch direction, we use an access
+ * function which preserves these bits.
+ */
+static void static_key_set_entries(struct static_key *key,
+				   struct jump_entry *entries)
+{
+	unsigned long type;
+
+	WARN_ON_ONCE((unsigned long)entries & JUMP_TYPE_MASK);
+	type = key->type & JUMP_TYPE_MASK;
+	key->entries = entries;
+	key->type |= type;
+}
+
+static enum jump_label_type jump_label_type(struct jump_entry *entry)
+{
+	struct static_key *key = jump_entry_key(entry);
+	bool enabled = static_key_enabled(key);
+	bool branch = jump_entry_is_branch(entry);
+
+	/* See the comment in linux/jump_label.h */
+	return enabled ^ branch;
+}
+
+static bool jump_label_can_update(struct jump_entry *entry, bool init)
+{
+	/*
+	 * Cannot update code that was in an init text area.
+	 */
+	if (!init && jump_entry_is_init(entry))
+		return false;
+
+	if (!kernel_text_address(jump_entry_code(entry))) {
+		/*
+		 * This skips patching built-in __exit, which
+		 * is part of init_section_contains() but is
+		 * not part of kernel_text_address().
+		 *
+		 * Skipping built-in __exit is fine since it
+		 * will never be executed.
+		 */
+		WARN_ONCE(!jump_entry_is_init(entry),
+			  "can't patch jump_label at %pS",
+			  (void *)jump_entry_code(entry));
+		return false;
+	}
+
+	return true;
+}
+
+#ifndef HAVE_JUMP_LABEL_BATCH
+static void __jump_label_update(struct static_key *key,
+				struct jump_entry *entry,
+				struct jump_entry *stop,
+				bool init)
+{
+	for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
+		if (jump_label_can_update(entry, init))
+			arch_jump_label_transform(entry, jump_label_type(entry));
+	}
+}
+#else
+static void __jump_label_update(struct static_key *key,
+				struct jump_entry *entry,
+				struct jump_entry *stop,
+				bool init)
+{
+	for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
+
+		if (!jump_label_can_update(entry, init))
+			continue;
+
+		if (!arch_jump_label_transform_queue(entry, jump_label_type(entry))) {
+			/*
+			 * Queue is full: Apply the current queue and try again.
+			 */
+			arch_jump_label_transform_apply();
+			BUG_ON(!arch_jump_label_transform_queue(entry, jump_label_type(entry)));
+		}
+	}
+	arch_jump_label_transform_apply();
+}
+#endif
+
+void __init jump_label_init(void)
+{
+	struct jump_entry *iter_start = __start___jump_table;
+	struct jump_entry *iter_stop = __stop___jump_table;
+	struct static_key *key = NULL;
+	struct jump_entry *iter;
+
+	/*
+	 * Since we are initializing the static_key.enabled field with
+	 * with the 'raw' int values (to avoid pulling in atomic.h) in
+	 * jump_label.h, let's make sure that is safe. There are only two
+	 * cases to check since we initialize to 0 or 1.
+	 */
+	BUILD_BUG_ON((int)ATOMIC_INIT(0) != 0);
+	BUILD_BUG_ON((int)ATOMIC_INIT(1) != 1);
+
+	if (static_key_initialized)
+		return;
+
+	cpus_read_lock();
+	jump_label_lock();
+	jump_label_sort_entries(iter_start, iter_stop);
+
+	for (iter = iter_start; iter < iter_stop; iter++) {
+		struct static_key *iterk;
+		bool in_init;
+
+		/* rewrite NOPs */
+		if (jump_label_type(iter) == JUMP_LABEL_NOP)
+			arch_jump_label_transform_static(iter, JUMP_LABEL_NOP);
+
+		in_init = init_section_contains((void *)jump_entry_code(iter), 1);
+		jump_entry_set_init(iter, in_init);
+
+		iterk = jump_entry_key(iter);
+		if (iterk == key)
+			continue;
+
+		key = iterk;
+		static_key_set_entries(key, iter);
+	}
+	static_key_initialized = true;
+	jump_label_unlock();
+	cpus_read_unlock();
+}
+
+#ifdef CONFIG_MODULES
+
+enum jump_label_type jump_label_init_type(struct jump_entry *entry)
+{
+	struct static_key *key = jump_entry_key(entry);
+	bool type = static_key_type(key);
+	bool branch = jump_entry_is_branch(entry);
+
+	/* See the comment in linux/jump_label.h */
+	return type ^ branch;
+}
+
+struct static_key_mod {
+	struct static_key_mod *next;
+	struct jump_entry *entries;
+	struct module *mod;
+};
+
+static inline struct static_key_mod *static_key_mod(struct static_key *key)
+{
+	WARN_ON_ONCE(!static_key_linked(key));
+	return (struct static_key_mod *)(key->type & ~JUMP_TYPE_MASK);
+}
+
+/***
+ * key->type and key->next are the same via union.
+ * This sets key->next and preserves the type bits.
+ *
+ * See additional comments above static_key_set_entries().
+ */
+static void static_key_set_mod(struct static_key *key,
+			       struct static_key_mod *mod)
+{
+	unsigned long type;
+
+	WARN_ON_ONCE((unsigned long)mod & JUMP_TYPE_MASK);
+	type = key->type & JUMP_TYPE_MASK;
+	key->next = mod;
+	key->type |= type;
+}
+
+static int __jump_label_mod_text_reserved(void *start, void *end)
+{
+	struct module *mod;
+	int ret;
+
+	preempt_disable();
+	mod = __module_text_address((unsigned long)start);
+	WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
+	if (!try_module_get(mod))
+		mod = NULL;
+	preempt_enable();
+
+	if (!mod)
+		return 0;
+
+	ret = __jump_label_text_reserved(mod->jump_entries,
+				mod->jump_entries + mod->num_jump_entries,
+				start, end, mod->state == MODULE_STATE_COMING);
+
+	module_put(mod);
+
+	return ret;
+}
+
+static void __jump_label_mod_update(struct static_key *key)
+{
+	struct static_key_mod *mod;
+
+	for (mod = static_key_mod(key); mod; mod = mod->next) {
+		struct jump_entry *stop;
+		struct module *m;
+
+		/*
+		 * NULL if the static_key is defined in a module
+		 * that does not use it
+		 */
+		if (!mod->entries)
+			continue;
+
+		m = mod->mod;
+		if (!m)
+			stop = __stop___jump_table;
+		else
+			stop = m->jump_entries + m->num_jump_entries;
+		__jump_label_update(key, mod->entries, stop,
+				    m && m->state == MODULE_STATE_COMING);
+	}
+}
+
+static int jump_label_add_module(struct module *mod)
+{
+	struct jump_entry *iter_start = mod->jump_entries;
+	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
+	struct jump_entry *iter;
+	struct static_key *key = NULL;
+	struct static_key_mod *jlm, *jlm2;
+
+	/* if the module doesn't have jump label entries, just return */
+	if (iter_start == iter_stop)
+		return 0;
+
+	jump_label_sort_entries(iter_start, iter_stop);
+
+	for (iter = iter_start; iter < iter_stop; iter++) {
+		struct static_key *iterk;
+		bool in_init;
+
+		in_init = within_module_init(jump_entry_code(iter), mod);
+		jump_entry_set_init(iter, in_init);
+
+		iterk = jump_entry_key(iter);
+		if (iterk == key)
+			continue;
+
+		key = iterk;
+		if (within_module((unsigned long)key, mod)) {
+			static_key_set_entries(key, iter);
+			continue;
+		}
+		jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
+		if (!jlm)
+			return -ENOMEM;
+		if (!static_key_linked(key)) {
+			jlm2 = kzalloc(sizeof(struct static_key_mod),
+				       GFP_KERNEL);
+			if (!jlm2) {
+				kfree(jlm);
+				return -ENOMEM;
+			}
+			preempt_disable();
+			jlm2->mod = __module_address((unsigned long)key);
+			preempt_enable();
+			jlm2->entries = static_key_entries(key);
+			jlm2->next = NULL;
+			static_key_set_mod(key, jlm2);
+			static_key_set_linked(key);
+		}
+		jlm->mod = mod;
+		jlm->entries = iter;
+		jlm->next = static_key_mod(key);
+		static_key_set_mod(key, jlm);
+		static_key_set_linked(key);
+
+		/* Only update if we've changed from our initial state */
+		if (jump_label_type(iter) != jump_label_init_type(iter))
+			__jump_label_update(key, iter, iter_stop, true);
+	}
+
+	return 0;
+}
+
+static void jump_label_del_module(struct module *mod)
+{
+	struct jump_entry *iter_start = mod->jump_entries;
+	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
+	struct jump_entry *iter;
+	struct static_key *key = NULL;
+	struct static_key_mod *jlm, **prev;
+
+	for (iter = iter_start; iter < iter_stop; iter++) {
+		if (jump_entry_key(iter) == key)
+			continue;
+
+		key = jump_entry_key(iter);
+
+		if (within_module((unsigned long)key, mod))
+			continue;
+
+		/* No memory during module load */
+		if (WARN_ON(!static_key_linked(key)))
+			continue;
+
+		prev = &key->next;
+		jlm = static_key_mod(key);
+
+		while (jlm && jlm->mod != mod) {
+			prev = &jlm->next;
+			jlm = jlm->next;
+		}
+
+		/* No memory during module load */
+		if (WARN_ON(!jlm))
+			continue;
+
+		if (prev == &key->next)
+			static_key_set_mod(key, jlm->next);
+		else
+			*prev = jlm->next;
+
+		kfree(jlm);
+
+		jlm = static_key_mod(key);
+		/* if only one etry is left, fold it back into the static_key */
+		if (jlm->next == NULL) {
+			static_key_set_entries(key, jlm->entries);
+			static_key_clear_linked(key);
+			kfree(jlm);
+		}
+	}
+}
+
+static int
+jump_label_module_notify(struct notifier_block *self, unsigned long val,
+			 void *data)
+{
+	struct module *mod = data;
+	int ret = 0;
+
+	cpus_read_lock();
+	jump_label_lock();
+
+	switch (val) {
+	case MODULE_STATE_COMING:
+		ret = jump_label_add_module(mod);
+		if (ret) {
+			WARN(1, "Failed to allocate memory: jump_label may not work properly.\n");
+			jump_label_del_module(mod);
+		}
+		break;
+	case MODULE_STATE_GOING:
+		jump_label_del_module(mod);
+		break;
+	}
+
+	jump_label_unlock();
+	cpus_read_unlock();
+
+	return notifier_from_errno(ret);
+}
+
+static struct notifier_block jump_label_module_nb = {
+	.notifier_call = jump_label_module_notify,
+	.priority = 1, /* higher than tracepoints */
+};
+
+static __init int jump_label_init_module(void)
+{
+	return register_module_notifier(&jump_label_module_nb);
+}
+early_initcall(jump_label_init_module);
+
+#endif /* CONFIG_MODULES */
+
+/***
+ * jump_label_text_reserved - check if addr range is reserved
+ * @start: start text addr
+ * @end: end text addr
+ *
+ * checks if the text addr located between @start and @end
+ * overlaps with any of the jump label patch addresses. Code
+ * that wants to modify kernel text should first verify that
+ * it does not overlap with any of the jump label addresses.
+ * Caller must hold jump_label_mutex.
+ *
+ * returns 1 if there is an overlap, 0 otherwise
+ */
+int jump_label_text_reserved(void *start, void *end)
+{
+	bool init = system_state < SYSTEM_RUNNING;
+	int ret = __jump_label_text_reserved(__start___jump_table,
+			__stop___jump_table, start, end, init);
+
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_MODULES
+	ret = __jump_label_mod_text_reserved(start, end);
+#endif
+	return ret;
+}
+
+static void jump_label_update(struct static_key *key)
+{
+	struct jump_entry *stop = __stop___jump_table;
+	bool init = system_state < SYSTEM_RUNNING;
+	struct jump_entry *entry;
+#ifdef CONFIG_MODULES
+	struct module *mod;
+
+	if (static_key_linked(key)) {
+		__jump_label_mod_update(key);
+		return;
+	}
+
+	preempt_disable();
+	mod = __module_address((unsigned long)key);
+	if (mod) {
+		stop = mod->jump_entries + mod->num_jump_entries;
+		init = mod->state == MODULE_STATE_COMING;
+	}
+	preempt_enable();
+#endif
+	entry = static_key_entries(key);
+	/* if there are no users, entry can be NULL */
+	if (entry)
+		__jump_label_update(key, entry, stop, init);
+}
+
+#ifdef CONFIG_STATIC_KEYS_SELFTEST
+static DEFINE_STATIC_KEY_TRUE(sk_true);
+static DEFINE_STATIC_KEY_FALSE(sk_false);
+
+static __init int jump_label_test(void)
+{
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		WARN_ON(static_key_enabled(&sk_true.key) != true);
+		WARN_ON(static_key_enabled(&sk_false.key) != false);
+
+		WARN_ON(!static_branch_likely(&sk_true));
+		WARN_ON(!static_branch_unlikely(&sk_true));
+		WARN_ON(static_branch_likely(&sk_false));
+		WARN_ON(static_branch_unlikely(&sk_false));
+
+		static_branch_disable(&sk_true);
+		static_branch_enable(&sk_false);
+
+		WARN_ON(static_key_enabled(&sk_true.key) == true);
+		WARN_ON(static_key_enabled(&sk_false.key) == false);
+
+		WARN_ON(static_branch_likely(&sk_true));
+		WARN_ON(static_branch_unlikely(&sk_true));
+		WARN_ON(!static_branch_likely(&sk_false));
+		WARN_ON(!static_branch_unlikely(&sk_false));
+
+		static_branch_enable(&sk_true);
+		static_branch_disable(&sk_false);
+	}
+
+	return 0;
+}
+early_initcall(jump_label_test);
+#endif /* STATIC_KEYS_SELFTEST */
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
new file mode 100644
index 000000000..824bcc7b5
--- /dev/null
+++ b/kernel/kallsyms.c
@@ -0,0 +1,1049 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
+ *
+ * Rewritten and vastly simplified by Rusty Russell for in-kernel
+ * module loader:
+ *   Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
+ *
+ * ChangeLog:
+ *
+ * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
+ *      Changed the compression method from stem compression to "table lookup"
+ *      compression (see scripts/kallsyms.c for a more complete description)
+ */
+#include <linux/kallsyms.h>
+#include <linux/init.h>
+#include <linux/seq_file.h>
+#include <linux/fs.h>
+#include <linux/kdb.h>
+#include <linux/err.h>
+#include <linux/proc_fs.h>
+#include <linux/sched.h>	/* for cond_resched */
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <linux/filter.h>
+#include <linux/ftrace.h>
+#include <linux/kprobes.h>
+#include <linux/build_bug.h>
+#include <linux/compiler.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/bsearch.h>
+#include <linux/btf_ids.h>
+
+#include "kallsyms_internal.h"
+
+/*
+ * Expand a compressed symbol data into the resulting uncompressed string,
+ * if uncompressed string is too long (>= maxlen), it will be truncated,
+ * given the offset to where the symbol is in the compressed stream.
+ */
+static unsigned int kallsyms_expand_symbol(unsigned int off,
+					   char *result, size_t maxlen)
+{
+	int len, skipped_first = 0;
+	const char *tptr;
+	const u8 *data;
+
+	/* Get the compressed symbol length from the first symbol byte. */
+	data = &kallsyms_names[off];
+	len = *data;
+	data++;
+	off++;
+
+	/* If MSB is 1, it is a "big" symbol, so needs an additional byte. */
+	if ((len & 0x80) != 0) {
+		len = (len & 0x7F) | (*data << 7);
+		data++;
+		off++;
+	}
+
+	/*
+	 * Update the offset to return the offset for the next symbol on
+	 * the compressed stream.
+	 */
+	off += len;
+
+	/*
+	 * For every byte on the compressed symbol data, copy the table
+	 * entry for that byte.
+	 */
+	while (len) {
+		tptr = &kallsyms_token_table[kallsyms_token_index[*data]];
+		data++;
+		len--;
+
+		while (*tptr) {
+			if (skipped_first) {
+				if (maxlen <= 1)
+					goto tail;
+				*result = *tptr;
+				result++;
+				maxlen--;
+			} else
+				skipped_first = 1;
+			tptr++;
+		}
+	}
+
+tail:
+	if (maxlen)
+		*result = '\0';
+
+	/* Return to offset to the next symbol. */
+	return off;
+}
+
+/*
+ * Get symbol type information. This is encoded as a single char at the
+ * beginning of the symbol name.
+ */
+static char kallsyms_get_symbol_type(unsigned int off)
+{
+	/*
+	 * Get just the first code, look it up in the token table,
+	 * and return the first char from this token.
+	 */
+	return kallsyms_token_table[kallsyms_token_index[kallsyms_names[off + 1]]];
+}
+
+
+/*
+ * Find the offset on the compressed stream given and index in the
+ * kallsyms array.
+ */
+static unsigned int get_symbol_offset(unsigned long pos)
+{
+	const u8 *name;
+	int i, len;
+
+	/*
+	 * Use the closest marker we have. We have markers every 256 positions,
+	 * so that should be close enough.
+	 */
+	name = &kallsyms_names[kallsyms_markers[pos >> 8]];
+
+	/*
+	 * Sequentially scan all the symbols up to the point we're searching
+	 * for. Every symbol is stored in a [<len>][<len> bytes of data] format,
+	 * so we just need to add the len to the current pointer for every
+	 * symbol we wish to skip.
+	 */
+	for (i = 0; i < (pos & 0xFF); i++) {
+		len = *name;
+
+		/*
+		 * If MSB is 1, it is a "big" symbol, so we need to look into
+		 * the next byte (and skip it, too).
+		 */
+		if ((len & 0x80) != 0)
+			len = ((len & 0x7F) | (name[1] << 7)) + 1;
+
+		name = name + len + 1;
+	}
+
+	return name - kallsyms_names;
+}
+
+static unsigned long kallsyms_sym_address(int idx)
+{
+	if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
+		return kallsyms_addresses[idx];
+
+	/* values are unsigned offsets if --absolute-percpu is not in effect */
+	if (!IS_ENABLED(CONFIG_KALLSYMS_ABSOLUTE_PERCPU))
+		return kallsyms_relative_base + (u32)kallsyms_offsets[idx];
+
+	/* ...otherwise, positive offsets are absolute values */
+	if (kallsyms_offsets[idx] >= 0)
+		return kallsyms_offsets[idx];
+
+	/* ...and negative offsets are relative to kallsyms_relative_base - 1 */
+	return kallsyms_relative_base - 1 - kallsyms_offsets[idx];
+}
+
+static bool cleanup_symbol_name(char *s)
+{
+	char *res;
+
+	if (!IS_ENABLED(CONFIG_LTO_CLANG))
+		return false;
+
+	/*
+	 * LLVM appends various suffixes for local functions and variables that
+	 * must be promoted to global scope as part of LTO.  This can break
+	 * hooking of static functions with kprobes. '.' is not a valid
+	 * character in an identifier in C. Suffixes only in LLVM LTO observed:
+	 * - foo.llvm.[0-9a-f]+
+	 */
+	res = strstr(s, ".llvm.");
+	if (res) {
+		*res = '\0';
+		return true;
+	}
+
+	return false;
+}
+
+static int compare_symbol_name(const char *name, char *namebuf)
+{
+	/* The kallsyms_seqs_of_names is sorted based on names after
+	 * cleanup_symbol_name() (see scripts/kallsyms.c) if clang lto is enabled.
+	 * To ensure correct bisection in kallsyms_lookup_names(), do
+	 * cleanup_symbol_name(namebuf) before comparing name and namebuf.
+	 */
+	cleanup_symbol_name(namebuf);
+	return strcmp(name, namebuf);
+}
+
+static unsigned int get_symbol_seq(int index)
+{
+	unsigned int i, seq = 0;
+
+	for (i = 0; i < 3; i++)
+		seq = (seq << 8) | kallsyms_seqs_of_names[3 * index + i];
+
+	return seq;
+}
+
+static int kallsyms_lookup_names(const char *name,
+				 unsigned int *start,
+				 unsigned int *end)
+{
+	int ret;
+	int low, mid, high;
+	unsigned int seq, off;
+	char namebuf[KSYM_NAME_LEN];
+
+	low = 0;
+	high = kallsyms_num_syms - 1;
+
+	while (low <= high) {
+		mid = low + (high - low) / 2;
+		seq = get_symbol_seq(mid);
+		off = get_symbol_offset(seq);
+		kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
+		ret = compare_symbol_name(name, namebuf);
+		if (ret > 0)
+			low = mid + 1;
+		else if (ret < 0)
+			high = mid - 1;
+		else
+			break;
+	}
+
+	if (low > high)
+		return -ESRCH;
+
+	low = mid;
+	while (low) {
+		seq = get_symbol_seq(low - 1);
+		off = get_symbol_offset(seq);
+		kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
+		if (compare_symbol_name(name, namebuf))
+			break;
+		low--;
+	}
+	*start = low;
+
+	if (end) {
+		high = mid;
+		while (high < kallsyms_num_syms - 1) {
+			seq = get_symbol_seq(high + 1);
+			off = get_symbol_offset(seq);
+			kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
+			if (compare_symbol_name(name, namebuf))
+				break;
+			high++;
+		}
+		*end = high;
+	}
+
+	return 0;
+}
+
+/* Lookup the address for this symbol. Returns 0 if not found. */
+unsigned long kallsyms_lookup_name(const char *name)
+{
+	int ret;
+	unsigned int i;
+
+	/* Skip the search for empty string. */
+	if (!*name)
+		return 0;
+
+	ret = kallsyms_lookup_names(name, &i, NULL);
+	if (!ret)
+		return kallsyms_sym_address(get_symbol_seq(i));
+
+	return module_kallsyms_lookup_name(name);
+}
+
+/*
+ * Iterate over all symbols in vmlinux.  For symbols from modules use
+ * module_kallsyms_on_each_symbol instead.
+ */
+int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
+				      unsigned long),
+			    void *data)
+{
+	char namebuf[KSYM_NAME_LEN];
+	unsigned long i;
+	unsigned int off;
+	int ret;
+
+	for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
+		off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
+		ret = fn(data, namebuf, NULL, kallsyms_sym_address(i));
+		if (ret != 0)
+			return ret;
+		cond_resched();
+	}
+	return 0;
+}
+
+int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),
+				  const char *name, void *data)
+{
+	int ret;
+	unsigned int i, start, end;
+
+	ret = kallsyms_lookup_names(name, &start, &end);
+	if (ret)
+		return 0;
+
+	for (i = start; !ret && i <= end; i++) {
+		ret = fn(data, kallsyms_sym_address(get_symbol_seq(i)));
+		cond_resched();
+	}
+
+	return ret;
+}
+
+static unsigned long get_symbol_pos(unsigned long addr,
+				    unsigned long *symbolsize,
+				    unsigned long *offset)
+{
+	unsigned long symbol_start = 0, symbol_end = 0;
+	unsigned long i, low, high, mid;
+
+	/* This kernel should never had been booted. */
+	if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
+		BUG_ON(!kallsyms_addresses);
+	else
+		BUG_ON(!kallsyms_offsets);
+
+	/* Do a binary search on the sorted kallsyms_addresses array. */
+	low = 0;
+	high = kallsyms_num_syms;
+
+	while (high - low > 1) {
+		mid = low + (high - low) / 2;
+		if (kallsyms_sym_address(mid) <= addr)
+			low = mid;
+		else
+			high = mid;
+	}
+
+	/*
+	 * Search for the first aliased symbol. Aliased
+	 * symbols are symbols with the same address.
+	 */
+	while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low))
+		--low;
+
+	symbol_start = kallsyms_sym_address(low);
+
+	/* Search for next non-aliased symbol. */
+	for (i = low + 1; i < kallsyms_num_syms; i++) {
+		if (kallsyms_sym_address(i) > symbol_start) {
+			symbol_end = kallsyms_sym_address(i);
+			break;
+		}
+	}
+
+	/* If we found no next symbol, we use the end of the section. */
+	if (!symbol_end) {
+		if (is_kernel_inittext(addr))
+			symbol_end = (unsigned long)_einittext;
+		else if (IS_ENABLED(CONFIG_KALLSYMS_ALL))
+			symbol_end = (unsigned long)_end;
+		else
+			symbol_end = (unsigned long)_etext;
+	}
+
+	if (symbolsize)
+		*symbolsize = symbol_end - symbol_start;
+	if (offset)
+		*offset = addr - symbol_start;
+
+	return low;
+}
+
+/*
+ * Lookup an address but don't bother to find any names.
+ */
+int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
+				unsigned long *offset)
+{
+	char namebuf[KSYM_NAME_LEN];
+
+	if (is_ksym_addr(addr)) {
+		get_symbol_pos(addr, symbolsize, offset);
+		return 1;
+	}
+	return !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf) ||
+	       !!__bpf_address_lookup(addr, symbolsize, offset, namebuf);
+}
+
+static const char *kallsyms_lookup_buildid(unsigned long addr,
+			unsigned long *symbolsize,
+			unsigned long *offset, char **modname,
+			const unsigned char **modbuildid, char *namebuf)
+{
+	const char *ret;
+
+	namebuf[KSYM_NAME_LEN - 1] = 0;
+	namebuf[0] = 0;
+
+	if (is_ksym_addr(addr)) {
+		unsigned long pos;
+
+		pos = get_symbol_pos(addr, symbolsize, offset);
+		/* Grab name */
+		kallsyms_expand_symbol(get_symbol_offset(pos),
+				       namebuf, KSYM_NAME_LEN);
+		if (modname)
+			*modname = NULL;
+		if (modbuildid)
+			*modbuildid = NULL;
+
+		ret = namebuf;
+		goto found;
+	}
+
+	/* See if it's in a module or a BPF JITed image. */
+	ret = module_address_lookup(addr, symbolsize, offset,
+				    modname, modbuildid, namebuf);
+	if (!ret)
+		ret = bpf_address_lookup(addr, symbolsize,
+					 offset, modname, namebuf);
+
+	if (!ret)
+		ret = ftrace_mod_address_lookup(addr, symbolsize,
+						offset, modname, namebuf);
+
+found:
+	cleanup_symbol_name(namebuf);
+	return ret;
+}
+
+/*
+ * Lookup an address
+ * - modname is set to NULL if it's in the kernel.
+ * - We guarantee that the returned name is valid until we reschedule even if.
+ *   It resides in a module.
+ * - We also guarantee that modname will be valid until rescheduled.
+ */
+const char *kallsyms_lookup(unsigned long addr,
+			    unsigned long *symbolsize,
+			    unsigned long *offset,
+			    char **modname, char *namebuf)
+{
+	return kallsyms_lookup_buildid(addr, symbolsize, offset, modname,
+				       NULL, namebuf);
+}
+
+int lookup_symbol_name(unsigned long addr, char *symname)
+{
+	int res;
+
+	symname[0] = '\0';
+	symname[KSYM_NAME_LEN - 1] = '\0';
+
+	if (is_ksym_addr(addr)) {
+		unsigned long pos;
+
+		pos = get_symbol_pos(addr, NULL, NULL);
+		/* Grab name */
+		kallsyms_expand_symbol(get_symbol_offset(pos),
+				       symname, KSYM_NAME_LEN);
+		goto found;
+	}
+	/* See if it's in a module. */
+	res = lookup_module_symbol_name(addr, symname);
+	if (res)
+		return res;
+
+found:
+	cleanup_symbol_name(symname);
+	return 0;
+}
+
+int lookup_symbol_attrs(unsigned long addr, unsigned long *size,
+			unsigned long *offset, char *modname, char *name)
+{
+	int res;
+
+	name[0] = '\0';
+	name[KSYM_NAME_LEN - 1] = '\0';
+
+	if (is_ksym_addr(addr)) {
+		unsigned long pos;
+
+		pos = get_symbol_pos(addr, size, offset);
+		/* Grab name */
+		kallsyms_expand_symbol(get_symbol_offset(pos),
+				       name, KSYM_NAME_LEN);
+		modname[0] = '\0';
+		goto found;
+	}
+	/* See if it's in a module. */
+	res = lookup_module_symbol_attrs(addr, size, offset, modname, name);
+	if (res)
+		return res;
+
+found:
+	cleanup_symbol_name(name);
+	return 0;
+}
+
+/* Look up a kernel symbol and return it in a text buffer. */
+static int __sprint_symbol(char *buffer, unsigned long address,
+			   int symbol_offset, int add_offset, int add_buildid)
+{
+	char *modname;
+	const unsigned char *buildid;
+	const char *name;
+	unsigned long offset, size;
+	int len;
+
+	address += symbol_offset;
+	name = kallsyms_lookup_buildid(address, &size, &offset, &modname, &buildid,
+				       buffer);
+	if (!name)
+		return sprintf(buffer, "0x%lx", address - symbol_offset);
+
+	if (name != buffer)
+		strcpy(buffer, name);
+	len = strlen(buffer);
+	offset -= symbol_offset;
+
+	if (add_offset)
+		len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);
+
+	if (modname) {
+		len += sprintf(buffer + len, " [%s", modname);
+#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
+		if (add_buildid && buildid) {
+			/* build ID should match length of sprintf */
+#if IS_ENABLED(CONFIG_MODULES)
+			static_assert(sizeof(typeof_member(struct module, build_id)) == 20);
+#endif
+			len += sprintf(buffer + len, " %20phN", buildid);
+		}
+#endif
+		len += sprintf(buffer + len, "]");
+	}
+
+	return len;
+}
+
+/**
+ * sprint_symbol - Look up a kernel symbol and return it in a text buffer
+ * @buffer: buffer to be stored
+ * @address: address to lookup
+ *
+ * This function looks up a kernel symbol with @address and stores its name,
+ * offset, size and module name to @buffer if possible. If no symbol was found,
+ * just saves its @address as is.
+ *
+ * This function returns the number of bytes stored in @buffer.
+ */
+int sprint_symbol(char *buffer, unsigned long address)
+{
+	return __sprint_symbol(buffer, address, 0, 1, 0);
+}
+EXPORT_SYMBOL_GPL(sprint_symbol);
+
+/**
+ * sprint_symbol_build_id - Look up a kernel symbol and return it in a text buffer
+ * @buffer: buffer to be stored
+ * @address: address to lookup
+ *
+ * This function looks up a kernel symbol with @address and stores its name,
+ * offset, size, module name and module build ID to @buffer if possible. If no
+ * symbol was found, just saves its @address as is.
+ *
+ * This function returns the number of bytes stored in @buffer.
+ */
+int sprint_symbol_build_id(char *buffer, unsigned long address)
+{
+	return __sprint_symbol(buffer, address, 0, 1, 1);
+}
+EXPORT_SYMBOL_GPL(sprint_symbol_build_id);
+
+/**
+ * sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer
+ * @buffer: buffer to be stored
+ * @address: address to lookup
+ *
+ * This function looks up a kernel symbol with @address and stores its name
+ * and module name to @buffer if possible. If no symbol was found, just saves
+ * its @address as is.
+ *
+ * This function returns the number of bytes stored in @buffer.
+ */
+int sprint_symbol_no_offset(char *buffer, unsigned long address)
+{
+	return __sprint_symbol(buffer, address, 0, 0, 0);
+}
+EXPORT_SYMBOL_GPL(sprint_symbol_no_offset);
+
+/**
+ * sprint_backtrace - Look up a backtrace symbol and return it in a text buffer
+ * @buffer: buffer to be stored
+ * @address: address to lookup
+ *
+ * This function is for stack backtrace and does the same thing as
+ * sprint_symbol() but with modified/decreased @address. If there is a
+ * tail-call to the function marked "noreturn", gcc optimized out code after
+ * the call so that the stack-saved return address could point outside of the
+ * caller. This function ensures that kallsyms will find the original caller
+ * by decreasing @address.
+ *
+ * This function returns the number of bytes stored in @buffer.
+ */
+int sprint_backtrace(char *buffer, unsigned long address)
+{
+	return __sprint_symbol(buffer, address, -1, 1, 0);
+}
+
+/**
+ * sprint_backtrace_build_id - Look up a backtrace symbol and return it in a text buffer
+ * @buffer: buffer to be stored
+ * @address: address to lookup
+ *
+ * This function is for stack backtrace and does the same thing as
+ * sprint_symbol() but with modified/decreased @address. If there is a
+ * tail-call to the function marked "noreturn", gcc optimized out code after
+ * the call so that the stack-saved return address could point outside of the
+ * caller. This function ensures that kallsyms will find the original caller
+ * by decreasing @address. This function also appends the module build ID to
+ * the @buffer if @address is within a kernel module.
+ *
+ * This function returns the number of bytes stored in @buffer.
+ */
+int sprint_backtrace_build_id(char *buffer, unsigned long address)
+{
+	return __sprint_symbol(buffer, address, -1, 1, 1);
+}
+
+/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
+struct kallsym_iter {
+	loff_t pos;
+	loff_t pos_arch_end;
+	loff_t pos_mod_end;
+	loff_t pos_ftrace_mod_end;
+	loff_t pos_bpf_end;
+	unsigned long value;
+	unsigned int nameoff; /* If iterating in core kernel symbols. */
+	char type;
+	char name[KSYM_NAME_LEN];
+	char module_name[MODULE_NAME_LEN];
+	int exported;
+	int show_value;
+};
+
+int __weak arch_get_kallsym(unsigned int symnum, unsigned long *value,
+			    char *type, char *name)
+{
+	return -EINVAL;
+}
+
+static int get_ksymbol_arch(struct kallsym_iter *iter)
+{
+	int ret = arch_get_kallsym(iter->pos - kallsyms_num_syms,
+				   &iter->value, &iter->type,
+				   iter->name);
+
+	if (ret < 0) {
+		iter->pos_arch_end = iter->pos;
+		return 0;
+	}
+
+	return 1;
+}
+
+static int get_ksymbol_mod(struct kallsym_iter *iter)
+{
+	int ret = module_get_kallsym(iter->pos - iter->pos_arch_end,
+				     &iter->value, &iter->type,
+				     iter->name, iter->module_name,
+				     &iter->exported);
+	if (ret < 0) {
+		iter->pos_mod_end = iter->pos;
+		return 0;
+	}
+
+	return 1;
+}
+
+/*
+ * ftrace_mod_get_kallsym() may also get symbols for pages allocated for ftrace
+ * purposes. In that case "__builtin__ftrace" is used as a module name, even
+ * though "__builtin__ftrace" is not a module.
+ */
+static int get_ksymbol_ftrace_mod(struct kallsym_iter *iter)
+{
+	int ret = ftrace_mod_get_kallsym(iter->pos - iter->pos_mod_end,
+					 &iter->value, &iter->type,
+					 iter->name, iter->module_name,
+					 &iter->exported);
+	if (ret < 0) {
+		iter->pos_ftrace_mod_end = iter->pos;
+		return 0;
+	}
+
+	return 1;
+}
+
+static int get_ksymbol_bpf(struct kallsym_iter *iter)
+{
+	int ret;
+
+	strlcpy(iter->module_name, "bpf", MODULE_NAME_LEN);
+	iter->exported = 0;
+	ret = bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end,
+			      &iter->value, &iter->type,
+			      iter->name);
+	if (ret < 0) {
+		iter->pos_bpf_end = iter->pos;
+		return 0;
+	}
+
+	return 1;
+}
+
+/*
+ * This uses "__builtin__kprobes" as a module name for symbols for pages
+ * allocated for kprobes' purposes, even though "__builtin__kprobes" is not a
+ * module.
+ */
+static int get_ksymbol_kprobe(struct kallsym_iter *iter)
+{
+	strlcpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN);
+	iter->exported = 0;
+	return kprobe_get_kallsym(iter->pos - iter->pos_bpf_end,
+				  &iter->value, &iter->type,
+				  iter->name) < 0 ? 0 : 1;
+}
+
+/* Returns space to next name. */
+static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
+{
+	unsigned off = iter->nameoff;
+
+	iter->module_name[0] = '\0';
+	iter->value = kallsyms_sym_address(iter->pos);
+
+	iter->type = kallsyms_get_symbol_type(off);
+
+	off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name));
+
+	return off - iter->nameoff;
+}
+
+static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
+{
+	iter->name[0] = '\0';
+	iter->nameoff = get_symbol_offset(new_pos);
+	iter->pos = new_pos;
+	if (new_pos == 0) {
+		iter->pos_arch_end = 0;
+		iter->pos_mod_end = 0;
+		iter->pos_ftrace_mod_end = 0;
+		iter->pos_bpf_end = 0;
+	}
+}
+
+/*
+ * The end position (last + 1) of each additional kallsyms section is recorded
+ * in iter->pos_..._end as each section is added, and so can be used to
+ * determine which get_ksymbol_...() function to call next.
+ */
+static int update_iter_mod(struct kallsym_iter *iter, loff_t pos)
+{
+	iter->pos = pos;
+
+	if ((!iter->pos_arch_end || iter->pos_arch_end > pos) &&
+	    get_ksymbol_arch(iter))
+		return 1;
+
+	if ((!iter->pos_mod_end || iter->pos_mod_end > pos) &&
+	    get_ksymbol_mod(iter))
+		return 1;
+
+	if ((!iter->pos_ftrace_mod_end || iter->pos_ftrace_mod_end > pos) &&
+	    get_ksymbol_ftrace_mod(iter))
+		return 1;
+
+	if ((!iter->pos_bpf_end || iter->pos_bpf_end > pos) &&
+	    get_ksymbol_bpf(iter))
+		return 1;
+
+	return get_ksymbol_kprobe(iter);
+}
+
+/* Returns false if pos at or past end of file. */
+static int update_iter(struct kallsym_iter *iter, loff_t pos)
+{
+	/* Module symbols can be accessed randomly. */
+	if (pos >= kallsyms_num_syms)
+		return update_iter_mod(iter, pos);
+
+	/* If we're not on the desired position, reset to new position. */
+	if (pos != iter->pos)
+		reset_iter(iter, pos);
+
+	iter->nameoff += get_ksymbol_core(iter);
+	iter->pos++;
+
+	return 1;
+}
+
+static void *s_next(struct seq_file *m, void *p, loff_t *pos)
+{
+	(*pos)++;
+
+	if (!update_iter(m->private, *pos))
+		return NULL;
+	return p;
+}
+
+static void *s_start(struct seq_file *m, loff_t *pos)
+{
+	if (!update_iter(m->private, *pos))
+		return NULL;
+	return m->private;
+}
+
+static void s_stop(struct seq_file *m, void *p)
+{
+}
+
+static int s_show(struct seq_file *m, void *p)
+{
+	void *value;
+	struct kallsym_iter *iter = m->private;
+
+	/* Some debugging symbols have no name.  Ignore them. */
+	if (!iter->name[0])
+		return 0;
+
+	value = iter->show_value ? (void *)iter->value : NULL;
+
+	if (iter->module_name[0]) {
+		char type;
+
+		/*
+		 * Label it "global" if it is exported,
+		 * "local" if not exported.
+		 */
+		type = iter->exported ? toupper(iter->type) :
+					tolower(iter->type);
+		seq_printf(m, "%px %c %s\t[%s]\n", value,
+			   type, iter->name, iter->module_name);
+	} else
+		seq_printf(m, "%px %c %s\n", value,
+			   iter->type, iter->name);
+	return 0;
+}
+
+static const struct seq_operations kallsyms_op = {
+	.start = s_start,
+	.next = s_next,
+	.stop = s_stop,
+	.show = s_show
+};
+
+#ifdef CONFIG_BPF_SYSCALL
+
+struct bpf_iter__ksym {
+	__bpf_md_ptr(struct bpf_iter_meta *, meta);
+	__bpf_md_ptr(struct kallsym_iter *, ksym);
+};
+
+static int ksym_prog_seq_show(struct seq_file *m, bool in_stop)
+{
+	struct bpf_iter__ksym ctx;
+	struct bpf_iter_meta meta;
+	struct bpf_prog *prog;
+
+	meta.seq = m;
+	prog = bpf_iter_get_info(&meta, in_stop);
+	if (!prog)
+		return 0;
+
+	ctx.meta = &meta;
+	ctx.ksym = m ? m->private : NULL;
+	return bpf_iter_run_prog(prog, &ctx);
+}
+
+static int bpf_iter_ksym_seq_show(struct seq_file *m, void *p)
+{
+	return ksym_prog_seq_show(m, false);
+}
+
+static void bpf_iter_ksym_seq_stop(struct seq_file *m, void *p)
+{
+	if (!p)
+		(void) ksym_prog_seq_show(m, true);
+	else
+		s_stop(m, p);
+}
+
+static const struct seq_operations bpf_iter_ksym_ops = {
+	.start = s_start,
+	.next = s_next,
+	.stop = bpf_iter_ksym_seq_stop,
+	.show = bpf_iter_ksym_seq_show,
+};
+
+static int bpf_iter_ksym_init(void *priv_data, struct bpf_iter_aux_info *aux)
+{
+	struct kallsym_iter *iter = priv_data;
+
+	reset_iter(iter, 0);
+
+	/* cache here as in kallsyms_open() case; use current process
+	 * credentials to tell BPF iterators if values should be shown.
+	 */
+	iter->show_value = kallsyms_show_value(current_cred());
+
+	return 0;
+}
+
+DEFINE_BPF_ITER_FUNC(ksym, struct bpf_iter_meta *meta, struct kallsym_iter *ksym)
+
+static const struct bpf_iter_seq_info ksym_iter_seq_info = {
+	.seq_ops		= &bpf_iter_ksym_ops,
+	.init_seq_private	= bpf_iter_ksym_init,
+	.fini_seq_private	= NULL,
+	.seq_priv_size		= sizeof(struct kallsym_iter),
+};
+
+static struct bpf_iter_reg ksym_iter_reg_info = {
+	.target                 = "ksym",
+	.feature		= BPF_ITER_RESCHED,
+	.ctx_arg_info_size	= 1,
+	.ctx_arg_info		= {
+		{ offsetof(struct bpf_iter__ksym, ksym),
+		  PTR_TO_BTF_ID_OR_NULL },
+	},
+	.seq_info		= &ksym_iter_seq_info,
+};
+
+BTF_ID_LIST(btf_ksym_iter_id)
+BTF_ID(struct, kallsym_iter)
+
+static int __init bpf_ksym_iter_register(void)
+{
+	ksym_iter_reg_info.ctx_arg_info[0].btf_id = *btf_ksym_iter_id;
+	return bpf_iter_reg_target(&ksym_iter_reg_info);
+}
+
+late_initcall(bpf_ksym_iter_register);
+
+#endif /* CONFIG_BPF_SYSCALL */
+
+static inline int kallsyms_for_perf(void)
+{
+#ifdef CONFIG_PERF_EVENTS
+	extern int sysctl_perf_event_paranoid;
+	if (sysctl_perf_event_paranoid <= 1)
+		return 1;
+#endif
+	return 0;
+}
+
+/*
+ * We show kallsyms information even to normal users if we've enabled
+ * kernel profiling and are explicitly not paranoid (so kptr_restrict
+ * is clear, and sysctl_perf_event_paranoid isn't set).
+ *
+ * Otherwise, require CAP_SYSLOG (assuming kptr_restrict isn't set to
+ * block even that).
+ */
+bool kallsyms_show_value(const struct cred *cred)
+{
+	switch (kptr_restrict) {
+	case 0:
+		if (kallsyms_for_perf())
+			return true;
+		fallthrough;
+	case 1:
+		if (security_capable(cred, &init_user_ns, CAP_SYSLOG,
+				     CAP_OPT_NOAUDIT) == 0)
+			return true;
+		fallthrough;
+	default:
+		return false;
+	}
+}
+
+static int kallsyms_open(struct inode *inode, struct file *file)
+{
+	/*
+	 * We keep iterator in m->private, since normal case is to
+	 * s_start from where we left off, so we avoid doing
+	 * using get_symbol_offset for every symbol.
+	 */
+	struct kallsym_iter *iter;
+	iter = __seq_open_private(file, &kallsyms_op, sizeof(*iter));
+	if (!iter)
+		return -ENOMEM;
+	reset_iter(iter, 0);
+
+	/*
+	 * Instead of checking this on every s_show() call, cache
+	 * the result here at open time.
+	 */
+	iter->show_value = kallsyms_show_value(file->f_cred);
+	return 0;
+}
+
+#ifdef	CONFIG_KGDB_KDB
+const char *kdb_walk_kallsyms(loff_t *pos)
+{
+	static struct kallsym_iter kdb_walk_kallsyms_iter;
+	if (*pos == 0) {
+		memset(&kdb_walk_kallsyms_iter, 0,
+		       sizeof(kdb_walk_kallsyms_iter));
+		reset_iter(&kdb_walk_kallsyms_iter, 0);
+	}
+	while (1) {
+		if (!update_iter(&kdb_walk_kallsyms_iter, *pos))
+			return NULL;
+		++*pos;
+		/* Some debugging symbols have no name.  Ignore them. */
+		if (kdb_walk_kallsyms_iter.name[0])
+			return kdb_walk_kallsyms_iter.name;
+	}
+}
+#endif	/* CONFIG_KGDB_KDB */
+
+static const struct proc_ops kallsyms_proc_ops = {
+	.proc_open	= kallsyms_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= seq_release_private,
+};
+
+static int __init kallsyms_init(void)
+{
+	proc_create("kallsyms", 0444, NULL, &kallsyms_proc_ops);
+	return 0;
+}
+device_initcall(kallsyms_init);
diff --git a/kernel/kallsyms_internal.h b/kernel/kallsyms_internal.h
new file mode 100644
index 000000000..27fabdcc4
--- /dev/null
+++ b/kernel/kallsyms_internal.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef LINUX_KALLSYMS_INTERNAL_H_
+#define LINUX_KALLSYMS_INTERNAL_H_
+
+#include <linux/types.h>
+
+/*
+ * These will be re-linked against their real values
+ * during the second link stage.
+ */
+extern const unsigned long kallsyms_addresses[] __weak;
+extern const int kallsyms_offsets[] __weak;
+extern const u8 kallsyms_names[] __weak;
+
+/*
+ * Tell the compiler that the count isn't in the small data section if the arch
+ * has one (eg: FRV).
+ */
+extern const unsigned int kallsyms_num_syms
+__section(".rodata") __attribute__((weak));
+
+extern const unsigned long kallsyms_relative_base
+__section(".rodata") __attribute__((weak));
+
+extern const char kallsyms_token_table[] __weak;
+extern const u16 kallsyms_token_index[] __weak;
+
+extern const unsigned int kallsyms_markers[] __weak;
+extern const u8 kallsyms_seqs_of_names[] __weak;
+
+#endif // LINUX_KALLSYMS_INTERNAL_H_
diff --git a/kernel/kcmp.c b/kernel/kcmp.c
new file mode 100644
index 000000000..5353edfad
--- /dev/null
+++ b/kernel/kcmp.c
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/syscalls.h>
+#include <linux/fdtable.h>
+#include <linux/string.h>
+#include <linux/random.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/cache.h>
+#include <linux/bug.h>
+#include <linux/err.h>
+#include <linux/kcmp.h>
+#include <linux/capability.h>
+#include <linux/list.h>
+#include <linux/eventpoll.h>
+#include <linux/file.h>
+
+#include <asm/unistd.h>
+
+/*
+ * We don't expose the real in-memory order of objects for security reasons.
+ * But still the comparison results should be suitable for sorting. So we
+ * obfuscate kernel pointers values and compare the production instead.
+ *
+ * The obfuscation is done in two steps. First we xor the kernel pointer with
+ * a random value, which puts pointer into a new position in a reordered space.
+ * Secondly we multiply the xor production with a large odd random number to
+ * permute its bits even more (the odd multiplier guarantees that the product
+ * is unique ever after the high bits are truncated, since any odd number is
+ * relative prime to 2^n).
+ *
+ * Note also that the obfuscation itself is invisible to userspace and if needed
+ * it can be changed to an alternate scheme.
+ */
+static unsigned long cookies[KCMP_TYPES][2] __read_mostly;
+
+static long kptr_obfuscate(long v, int type)
+{
+	return (v ^ cookies[type][0]) * cookies[type][1];
+}
+
+/*
+ * 0 - equal, i.e. v1 = v2
+ * 1 - less than, i.e. v1 < v2
+ * 2 - greater than, i.e. v1 > v2
+ * 3 - not equal but ordering unavailable (reserved for future)
+ */
+static int kcmp_ptr(void *v1, void *v2, enum kcmp_type type)
+{
+	long t1, t2;
+
+	t1 = kptr_obfuscate((long)v1, type);
+	t2 = kptr_obfuscate((long)v2, type);
+
+	return (t1 < t2) | ((t1 > t2) << 1);
+}
+
+/* The caller must have pinned the task */
+static struct file *
+get_file_raw_ptr(struct task_struct *task, unsigned int idx)
+{
+	struct file *file;
+
+	rcu_read_lock();
+	file = task_lookup_fd_rcu(task, idx);
+	rcu_read_unlock();
+
+	return file;
+}
+
+static void kcmp_unlock(struct rw_semaphore *l1, struct rw_semaphore *l2)
+{
+	if (likely(l2 != l1))
+		up_read(l2);
+	up_read(l1);
+}
+
+static int kcmp_lock(struct rw_semaphore *l1, struct rw_semaphore *l2)
+{
+	int err;
+
+	if (l2 > l1)
+		swap(l1, l2);
+
+	err = down_read_killable(l1);
+	if (!err && likely(l1 != l2)) {
+		err = down_read_killable_nested(l2, SINGLE_DEPTH_NESTING);
+		if (err)
+			up_read(l1);
+	}
+
+	return err;
+}
+
+#ifdef CONFIG_EPOLL
+static int kcmp_epoll_target(struct task_struct *task1,
+			     struct task_struct *task2,
+			     unsigned long idx1,
+			     struct kcmp_epoll_slot __user *uslot)
+{
+	struct file *filp, *filp_epoll, *filp_tgt;
+	struct kcmp_epoll_slot slot;
+
+	if (copy_from_user(&slot, uslot, sizeof(slot)))
+		return -EFAULT;
+
+	filp = get_file_raw_ptr(task1, idx1);
+	if (!filp)
+		return -EBADF;
+
+	filp_epoll = fget_task(task2, slot.efd);
+	if (!filp_epoll)
+		return -EBADF;
+
+	filp_tgt = get_epoll_tfile_raw_ptr(filp_epoll, slot.tfd, slot.toff);
+	fput(filp_epoll);
+
+	if (IS_ERR(filp_tgt))
+		return PTR_ERR(filp_tgt);
+
+	return kcmp_ptr(filp, filp_tgt, KCMP_FILE);
+}
+#else
+static int kcmp_epoll_target(struct task_struct *task1,
+			     struct task_struct *task2,
+			     unsigned long idx1,
+			     struct kcmp_epoll_slot __user *uslot)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
+SYSCALL_DEFINE5(kcmp, pid_t, pid1, pid_t, pid2, int, type,
+		unsigned long, idx1, unsigned long, idx2)
+{
+	struct task_struct *task1, *task2;
+	int ret;
+
+	rcu_read_lock();
+
+	/*
+	 * Tasks are looked up in caller's PID namespace only.
+	 */
+	task1 = find_task_by_vpid(pid1);
+	task2 = find_task_by_vpid(pid2);
+	if (!task1 || !task2)
+		goto err_no_task;
+
+	get_task_struct(task1);
+	get_task_struct(task2);
+
+	rcu_read_unlock();
+
+	/*
+	 * One should have enough rights to inspect task details.
+	 */
+	ret = kcmp_lock(&task1->signal->exec_update_lock,
+			&task2->signal->exec_update_lock);
+	if (ret)
+		goto err;
+	if (!ptrace_may_access(task1, PTRACE_MODE_READ_REALCREDS) ||
+	    !ptrace_may_access(task2, PTRACE_MODE_READ_REALCREDS)) {
+		ret = -EPERM;
+		goto err_unlock;
+	}
+
+	switch (type) {
+	case KCMP_FILE: {
+		struct file *filp1, *filp2;
+
+		filp1 = get_file_raw_ptr(task1, idx1);
+		filp2 = get_file_raw_ptr(task2, idx2);
+
+		if (filp1 && filp2)
+			ret = kcmp_ptr(filp1, filp2, KCMP_FILE);
+		else
+			ret = -EBADF;
+		break;
+	}
+	case KCMP_VM:
+		ret = kcmp_ptr(task1->mm, task2->mm, KCMP_VM);
+		break;
+	case KCMP_FILES:
+		ret = kcmp_ptr(task1->files, task2->files, KCMP_FILES);
+		break;
+	case KCMP_FS:
+		ret = kcmp_ptr(task1->fs, task2->fs, KCMP_FS);
+		break;
+	case KCMP_SIGHAND:
+		ret = kcmp_ptr(task1->sighand, task2->sighand, KCMP_SIGHAND);
+		break;
+	case KCMP_IO:
+		ret = kcmp_ptr(task1->io_context, task2->io_context, KCMP_IO);
+		break;
+	case KCMP_SYSVSEM:
+#ifdef CONFIG_SYSVIPC
+		ret = kcmp_ptr(task1->sysvsem.undo_list,
+			       task2->sysvsem.undo_list,
+			       KCMP_SYSVSEM);
+#else
+		ret = -EOPNOTSUPP;
+#endif
+		break;
+	case KCMP_EPOLL_TFD:
+		ret = kcmp_epoll_target(task1, task2, idx1, (void *)idx2);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+err_unlock:
+	kcmp_unlock(&task1->signal->exec_update_lock,
+		    &task2->signal->exec_update_lock);
+err:
+	put_task_struct(task1);
+	put_task_struct(task2);
+
+	return ret;
+
+err_no_task:
+	rcu_read_unlock();
+	return -ESRCH;
+}
+
+static __init int kcmp_cookies_init(void)
+{
+	int i;
+
+	get_random_bytes(cookies, sizeof(cookies));
+
+	for (i = 0; i < KCMP_TYPES; i++)
+		cookies[i][1] |= (~(~0UL >>  1) | 1);
+
+	return 0;
+}
+arch_initcall(kcmp_cookies_init);
diff --git a/kernel/kcov.c b/kernel/kcov.c
new file mode 100644
index 000000000..e5cd09fd8
--- /dev/null
+++ b/kernel/kcov.c
@@ -0,0 +1,1080 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) "kcov: " fmt
+
+#define DISABLE_BRANCH_PROFILING
+#include <linux/atomic.h>
+#include <linux/compiler.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/hashtable.h>
+#include <linux/init.h>
+#include <linux/kmsan-checks.h>
+#include <linux/mm.h>
+#include <linux/preempt.h>
+#include <linux/printk.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/kcov.h>
+#include <linux/refcount.h>
+#include <linux/log2.h>
+#include <asm/setup.h>
+
+#define kcov_debug(fmt, ...) pr_debug("%s: " fmt, __func__, ##__VA_ARGS__)
+
+/* Number of 64-bit words written per one comparison: */
+#define KCOV_WORDS_PER_CMP 4
+
+/*
+ * kcov descriptor (one per opened debugfs file).
+ * State transitions of the descriptor:
+ *  - initial state after open()
+ *  - then there must be a single ioctl(KCOV_INIT_TRACE) call
+ *  - then, mmap() call (several calls are allowed but not useful)
+ *  - then, ioctl(KCOV_ENABLE, arg), where arg is
+ *	KCOV_TRACE_PC - to trace only the PCs
+ *	or
+ *	KCOV_TRACE_CMP - to trace only the comparison operands
+ *  - then, ioctl(KCOV_DISABLE) to disable the task.
+ * Enabling/disabling ioctls can be repeated (only one task a time allowed).
+ */
+struct kcov {
+	/*
+	 * Reference counter. We keep one for:
+	 *  - opened file descriptor
+	 *  - task with enabled coverage (we can't unwire it from another task)
+	 *  - each code section for remote coverage collection
+	 */
+	refcount_t		refcount;
+	/* The lock protects mode, size, area and t. */
+	spinlock_t		lock;
+	enum kcov_mode		mode;
+	/* Size of arena (in long's). */
+	unsigned int		size;
+	/* Coverage buffer shared with user space. */
+	void			*area;
+	/* Task for which we collect coverage, or NULL. */
+	struct task_struct	*t;
+	/* Collecting coverage from remote (background) threads. */
+	bool			remote;
+	/* Size of remote area (in long's). */
+	unsigned int		remote_size;
+	/*
+	 * Sequence is incremented each time kcov is reenabled, used by
+	 * kcov_remote_stop(), see the comment there.
+	 */
+	int			sequence;
+};
+
+struct kcov_remote_area {
+	struct list_head	list;
+	unsigned int		size;
+};
+
+struct kcov_remote {
+	u64			handle;
+	struct kcov		*kcov;
+	struct hlist_node	hnode;
+};
+
+static DEFINE_SPINLOCK(kcov_remote_lock);
+static DEFINE_HASHTABLE(kcov_remote_map, 4);
+static struct list_head kcov_remote_areas = LIST_HEAD_INIT(kcov_remote_areas);
+
+struct kcov_percpu_data {
+	void			*irq_area;
+	local_lock_t		lock;
+
+	unsigned int		saved_mode;
+	unsigned int		saved_size;
+	void			*saved_area;
+	struct kcov		*saved_kcov;
+	int			saved_sequence;
+};
+
+static DEFINE_PER_CPU(struct kcov_percpu_data, kcov_percpu_data) = {
+	.lock = INIT_LOCAL_LOCK(lock),
+};
+
+/* Must be called with kcov_remote_lock locked. */
+static struct kcov_remote *kcov_remote_find(u64 handle)
+{
+	struct kcov_remote *remote;
+
+	hash_for_each_possible(kcov_remote_map, remote, hnode, handle) {
+		if (remote->handle == handle)
+			return remote;
+	}
+	return NULL;
+}
+
+/* Must be called with kcov_remote_lock locked. */
+static struct kcov_remote *kcov_remote_add(struct kcov *kcov, u64 handle)
+{
+	struct kcov_remote *remote;
+
+	if (kcov_remote_find(handle))
+		return ERR_PTR(-EEXIST);
+	remote = kmalloc(sizeof(*remote), GFP_ATOMIC);
+	if (!remote)
+		return ERR_PTR(-ENOMEM);
+	remote->handle = handle;
+	remote->kcov = kcov;
+	hash_add(kcov_remote_map, &remote->hnode, handle);
+	return remote;
+}
+
+/* Must be called with kcov_remote_lock locked. */
+static struct kcov_remote_area *kcov_remote_area_get(unsigned int size)
+{
+	struct kcov_remote_area *area;
+	struct list_head *pos;
+
+	list_for_each(pos, &kcov_remote_areas) {
+		area = list_entry(pos, struct kcov_remote_area, list);
+		if (area->size == size) {
+			list_del(&area->list);
+			return area;
+		}
+	}
+	return NULL;
+}
+
+/* Must be called with kcov_remote_lock locked. */
+static void kcov_remote_area_put(struct kcov_remote_area *area,
+					unsigned int size)
+{
+	INIT_LIST_HEAD(&area->list);
+	area->size = size;
+	list_add(&area->list, &kcov_remote_areas);
+	/*
+	 * KMSAN doesn't instrument this file, so it may not know area->list
+	 * is initialized. Unpoison it explicitly to avoid reports in
+	 * kcov_remote_area_get().
+	 */
+	kmsan_unpoison_memory(&area->list, sizeof(area->list));
+}
+
+static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t)
+{
+	unsigned int mode;
+
+	/*
+	 * We are interested in code coverage as a function of a syscall inputs,
+	 * so we ignore code executed in interrupts, unless we are in a remote
+	 * coverage collection section in a softirq.
+	 */
+	if (!in_task() && !(in_serving_softirq() && t->kcov_softirq))
+		return false;
+	mode = READ_ONCE(t->kcov_mode);
+	/*
+	 * There is some code that runs in interrupts but for which
+	 * in_interrupt() returns false (e.g. preempt_schedule_irq()).
+	 * READ_ONCE()/barrier() effectively provides load-acquire wrt
+	 * interrupts, there are paired barrier()/WRITE_ONCE() in
+	 * kcov_start().
+	 */
+	barrier();
+	return mode == needed_mode;
+}
+
+static notrace unsigned long canonicalize_ip(unsigned long ip)
+{
+#ifdef CONFIG_RANDOMIZE_BASE
+	ip -= kaslr_offset();
+#endif
+	return ip;
+}
+
+/*
+ * Entry point from instrumented code.
+ * This is called once per basic-block/edge.
+ */
+void notrace __sanitizer_cov_trace_pc(void)
+{
+	struct task_struct *t;
+	unsigned long *area;
+	unsigned long ip = canonicalize_ip(_RET_IP_);
+	unsigned long pos;
+
+	t = current;
+	if (!check_kcov_mode(KCOV_MODE_TRACE_PC, t))
+		return;
+
+	area = t->kcov_area;
+	/* The first 64-bit word is the number of subsequent PCs. */
+	pos = READ_ONCE(area[0]) + 1;
+	if (likely(pos < t->kcov_size)) {
+		/* Previously we write pc before updating pos. However, some
+		 * early interrupt code could bypass check_kcov_mode() check
+		 * and invoke __sanitizer_cov_trace_pc(). If such interrupt is
+		 * raised between writing pc and updating pos, the pc could be
+		 * overitten by the recursive __sanitizer_cov_trace_pc().
+		 * Update pos before writing pc to avoid such interleaving.
+		 */
+		WRITE_ONCE(area[0], pos);
+		barrier();
+		area[pos] = ip;
+	}
+}
+EXPORT_SYMBOL(__sanitizer_cov_trace_pc);
+
+#ifdef CONFIG_KCOV_ENABLE_COMPARISONS
+static void notrace write_comp_data(u64 type, u64 arg1, u64 arg2, u64 ip)
+{
+	struct task_struct *t;
+	u64 *area;
+	u64 count, start_index, end_pos, max_pos;
+
+	t = current;
+	if (!check_kcov_mode(KCOV_MODE_TRACE_CMP, t))
+		return;
+
+	ip = canonicalize_ip(ip);
+
+	/*
+	 * We write all comparison arguments and types as u64.
+	 * The buffer was allocated for t->kcov_size unsigned longs.
+	 */
+	area = (u64 *)t->kcov_area;
+	max_pos = t->kcov_size * sizeof(unsigned long);
+
+	count = READ_ONCE(area[0]);
+
+	/* Every record is KCOV_WORDS_PER_CMP 64-bit words. */
+	start_index = 1 + count * KCOV_WORDS_PER_CMP;
+	end_pos = (start_index + KCOV_WORDS_PER_CMP) * sizeof(u64);
+	if (likely(end_pos <= max_pos)) {
+		/* See comment in __sanitizer_cov_trace_pc(). */
+		WRITE_ONCE(area[0], count + 1);
+		barrier();
+		area[start_index] = type;
+		area[start_index + 1] = arg1;
+		area[start_index + 2] = arg2;
+		area[start_index + 3] = ip;
+	}
+}
+
+void notrace __sanitizer_cov_trace_cmp1(u8 arg1, u8 arg2)
+{
+	write_comp_data(KCOV_CMP_SIZE(0), arg1, arg2, _RET_IP_);
+}
+EXPORT_SYMBOL(__sanitizer_cov_trace_cmp1);
+
+void notrace __sanitizer_cov_trace_cmp2(u16 arg1, u16 arg2)
+{
+	write_comp_data(KCOV_CMP_SIZE(1), arg1, arg2, _RET_IP_);
+}
+EXPORT_SYMBOL(__sanitizer_cov_trace_cmp2);
+
+void notrace __sanitizer_cov_trace_cmp4(u32 arg1, u32 arg2)
+{
+	write_comp_data(KCOV_CMP_SIZE(2), arg1, arg2, _RET_IP_);
+}
+EXPORT_SYMBOL(__sanitizer_cov_trace_cmp4);
+
+void notrace __sanitizer_cov_trace_cmp8(u64 arg1, u64 arg2)
+{
+	write_comp_data(KCOV_CMP_SIZE(3), arg1, arg2, _RET_IP_);
+}
+EXPORT_SYMBOL(__sanitizer_cov_trace_cmp8);
+
+void notrace __sanitizer_cov_trace_const_cmp1(u8 arg1, u8 arg2)
+{
+	write_comp_data(KCOV_CMP_SIZE(0) | KCOV_CMP_CONST, arg1, arg2,
+			_RET_IP_);
+}
+EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp1);
+
+void notrace __sanitizer_cov_trace_const_cmp2(u16 arg1, u16 arg2)
+{
+	write_comp_data(KCOV_CMP_SIZE(1) | KCOV_CMP_CONST, arg1, arg2,
+			_RET_IP_);
+}
+EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp2);
+
+void notrace __sanitizer_cov_trace_const_cmp4(u32 arg1, u32 arg2)
+{
+	write_comp_data(KCOV_CMP_SIZE(2) | KCOV_CMP_CONST, arg1, arg2,
+			_RET_IP_);
+}
+EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp4);
+
+void notrace __sanitizer_cov_trace_const_cmp8(u64 arg1, u64 arg2)
+{
+	write_comp_data(KCOV_CMP_SIZE(3) | KCOV_CMP_CONST, arg1, arg2,
+			_RET_IP_);
+}
+EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp8);
+
+void notrace __sanitizer_cov_trace_switch(u64 val, u64 *cases)
+{
+	u64 i;
+	u64 count = cases[0];
+	u64 size = cases[1];
+	u64 type = KCOV_CMP_CONST;
+
+	switch (size) {
+	case 8:
+		type |= KCOV_CMP_SIZE(0);
+		break;
+	case 16:
+		type |= KCOV_CMP_SIZE(1);
+		break;
+	case 32:
+		type |= KCOV_CMP_SIZE(2);
+		break;
+	case 64:
+		type |= KCOV_CMP_SIZE(3);
+		break;
+	default:
+		return;
+	}
+	for (i = 0; i < count; i++)
+		write_comp_data(type, cases[i + 2], val, _RET_IP_);
+}
+EXPORT_SYMBOL(__sanitizer_cov_trace_switch);
+#endif /* ifdef CONFIG_KCOV_ENABLE_COMPARISONS */
+
+static void kcov_start(struct task_struct *t, struct kcov *kcov,
+			unsigned int size, void *area, enum kcov_mode mode,
+			int sequence)
+{
+	kcov_debug("t = %px, size = %u, area = %px\n", t, size, area);
+	t->kcov = kcov;
+	/* Cache in task struct for performance. */
+	t->kcov_size = size;
+	t->kcov_area = area;
+	t->kcov_sequence = sequence;
+	/* See comment in check_kcov_mode(). */
+	barrier();
+	WRITE_ONCE(t->kcov_mode, mode);
+}
+
+static void kcov_stop(struct task_struct *t)
+{
+	WRITE_ONCE(t->kcov_mode, KCOV_MODE_DISABLED);
+	barrier();
+	t->kcov = NULL;
+	t->kcov_size = 0;
+	t->kcov_area = NULL;
+}
+
+static void kcov_task_reset(struct task_struct *t)
+{
+	kcov_stop(t);
+	t->kcov_sequence = 0;
+	t->kcov_handle = 0;
+}
+
+void kcov_task_init(struct task_struct *t)
+{
+	kcov_task_reset(t);
+	t->kcov_handle = current->kcov_handle;
+}
+
+static void kcov_reset(struct kcov *kcov)
+{
+	kcov->t = NULL;
+	kcov->mode = KCOV_MODE_INIT;
+	kcov->remote = false;
+	kcov->remote_size = 0;
+	kcov->sequence++;
+}
+
+static void kcov_remote_reset(struct kcov *kcov)
+{
+	int bkt;
+	struct kcov_remote *remote;
+	struct hlist_node *tmp;
+	unsigned long flags;
+
+	spin_lock_irqsave(&kcov_remote_lock, flags);
+	hash_for_each_safe(kcov_remote_map, bkt, tmp, remote, hnode) {
+		if (remote->kcov != kcov)
+			continue;
+		hash_del(&remote->hnode);
+		kfree(remote);
+	}
+	/* Do reset before unlock to prevent races with kcov_remote_start(). */
+	kcov_reset(kcov);
+	spin_unlock_irqrestore(&kcov_remote_lock, flags);
+}
+
+static void kcov_disable(struct task_struct *t, struct kcov *kcov)
+{
+	kcov_task_reset(t);
+	if (kcov->remote)
+		kcov_remote_reset(kcov);
+	else
+		kcov_reset(kcov);
+}
+
+static void kcov_get(struct kcov *kcov)
+{
+	refcount_inc(&kcov->refcount);
+}
+
+static void kcov_put(struct kcov *kcov)
+{
+	if (refcount_dec_and_test(&kcov->refcount)) {
+		kcov_remote_reset(kcov);
+		vfree(kcov->area);
+		kfree(kcov);
+	}
+}
+
+void kcov_task_exit(struct task_struct *t)
+{
+	struct kcov *kcov;
+	unsigned long flags;
+
+	kcov = t->kcov;
+	if (kcov == NULL)
+		return;
+
+	spin_lock_irqsave(&kcov->lock, flags);
+	kcov_debug("t = %px, kcov->t = %px\n", t, kcov->t);
+	/*
+	 * For KCOV_ENABLE devices we want to make sure that t->kcov->t == t,
+	 * which comes down to:
+	 *        WARN_ON(!kcov->remote && kcov->t != t);
+	 *
+	 * For KCOV_REMOTE_ENABLE devices, the exiting task is either:
+	 *
+	 * 1. A remote task between kcov_remote_start() and kcov_remote_stop().
+	 *    In this case we should print a warning right away, since a task
+	 *    shouldn't be exiting when it's in a kcov coverage collection
+	 *    section. Here t points to the task that is collecting remote
+	 *    coverage, and t->kcov->t points to the thread that created the
+	 *    kcov device. Which means that to detect this case we need to
+	 *    check that t != t->kcov->t, and this gives us the following:
+	 *        WARN_ON(kcov->remote && kcov->t != t);
+	 *
+	 * 2. The task that created kcov exiting without calling KCOV_DISABLE,
+	 *    and then again we make sure that t->kcov->t == t:
+	 *        WARN_ON(kcov->remote && kcov->t != t);
+	 *
+	 * By combining all three checks into one we get:
+	 */
+	if (WARN_ON(kcov->t != t)) {
+		spin_unlock_irqrestore(&kcov->lock, flags);
+		return;
+	}
+	/* Just to not leave dangling references behind. */
+	kcov_disable(t, kcov);
+	spin_unlock_irqrestore(&kcov->lock, flags);
+	kcov_put(kcov);
+}
+
+static int kcov_mmap(struct file *filep, struct vm_area_struct *vma)
+{
+	int res = 0;
+	struct kcov *kcov = vma->vm_file->private_data;
+	unsigned long size, off;
+	struct page *page;
+	unsigned long flags;
+
+	spin_lock_irqsave(&kcov->lock, flags);
+	size = kcov->size * sizeof(unsigned long);
+	if (kcov->area == NULL || vma->vm_pgoff != 0 ||
+	    vma->vm_end - vma->vm_start != size) {
+		res = -EINVAL;
+		goto exit;
+	}
+	spin_unlock_irqrestore(&kcov->lock, flags);
+	vma->vm_flags |= VM_DONTEXPAND;
+	for (off = 0; off < size; off += PAGE_SIZE) {
+		page = vmalloc_to_page(kcov->area + off);
+		res = vm_insert_page(vma, vma->vm_start + off, page);
+		if (res) {
+			pr_warn_once("kcov: vm_insert_page() failed\n");
+			return res;
+		}
+	}
+	return 0;
+exit:
+	spin_unlock_irqrestore(&kcov->lock, flags);
+	return res;
+}
+
+static int kcov_open(struct inode *inode, struct file *filep)
+{
+	struct kcov *kcov;
+
+	kcov = kzalloc(sizeof(*kcov), GFP_KERNEL);
+	if (!kcov)
+		return -ENOMEM;
+	kcov->mode = KCOV_MODE_DISABLED;
+	kcov->sequence = 1;
+	refcount_set(&kcov->refcount, 1);
+	spin_lock_init(&kcov->lock);
+	filep->private_data = kcov;
+	return nonseekable_open(inode, filep);
+}
+
+static int kcov_close(struct inode *inode, struct file *filep)
+{
+	kcov_put(filep->private_data);
+	return 0;
+}
+
+static int kcov_get_mode(unsigned long arg)
+{
+	if (arg == KCOV_TRACE_PC)
+		return KCOV_MODE_TRACE_PC;
+	else if (arg == KCOV_TRACE_CMP)
+#ifdef CONFIG_KCOV_ENABLE_COMPARISONS
+		return KCOV_MODE_TRACE_CMP;
+#else
+		return -ENOTSUPP;
+#endif
+	else
+		return -EINVAL;
+}
+
+/*
+ * Fault in a lazily-faulted vmalloc area before it can be used by
+ * __santizer_cov_trace_pc(), to avoid recursion issues if any code on the
+ * vmalloc fault handling path is instrumented.
+ */
+static void kcov_fault_in_area(struct kcov *kcov)
+{
+	unsigned long stride = PAGE_SIZE / sizeof(unsigned long);
+	unsigned long *area = kcov->area;
+	unsigned long offset;
+
+	for (offset = 0; offset < kcov->size; offset += stride)
+		READ_ONCE(area[offset]);
+}
+
+static inline bool kcov_check_handle(u64 handle, bool common_valid,
+				bool uncommon_valid, bool zero_valid)
+{
+	if (handle & ~(KCOV_SUBSYSTEM_MASK | KCOV_INSTANCE_MASK))
+		return false;
+	switch (handle & KCOV_SUBSYSTEM_MASK) {
+	case KCOV_SUBSYSTEM_COMMON:
+		return (handle & KCOV_INSTANCE_MASK) ?
+			common_valid : zero_valid;
+	case KCOV_SUBSYSTEM_USB:
+		return uncommon_valid;
+	default:
+		return false;
+	}
+	return false;
+}
+
+static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
+			     unsigned long arg)
+{
+	struct task_struct *t;
+	unsigned long flags, unused;
+	int mode, i;
+	struct kcov_remote_arg *remote_arg;
+	struct kcov_remote *remote;
+
+	switch (cmd) {
+	case KCOV_ENABLE:
+		/*
+		 * Enable coverage for the current task.
+		 * At this point user must have been enabled trace mode,
+		 * and mmapped the file. Coverage collection is disabled only
+		 * at task exit or voluntary by KCOV_DISABLE. After that it can
+		 * be enabled for another task.
+		 */
+		if (kcov->mode != KCOV_MODE_INIT || !kcov->area)
+			return -EINVAL;
+		t = current;
+		if (kcov->t != NULL || t->kcov != NULL)
+			return -EBUSY;
+		mode = kcov_get_mode(arg);
+		if (mode < 0)
+			return mode;
+		kcov_fault_in_area(kcov);
+		kcov->mode = mode;
+		kcov_start(t, kcov, kcov->size, kcov->area, kcov->mode,
+				kcov->sequence);
+		kcov->t = t;
+		/* Put either in kcov_task_exit() or in KCOV_DISABLE. */
+		kcov_get(kcov);
+		return 0;
+	case KCOV_DISABLE:
+		/* Disable coverage for the current task. */
+		unused = arg;
+		if (unused != 0 || current->kcov != kcov)
+			return -EINVAL;
+		t = current;
+		if (WARN_ON(kcov->t != t))
+			return -EINVAL;
+		kcov_disable(t, kcov);
+		kcov_put(kcov);
+		return 0;
+	case KCOV_REMOTE_ENABLE:
+		if (kcov->mode != KCOV_MODE_INIT || !kcov->area)
+			return -EINVAL;
+		t = current;
+		if (kcov->t != NULL || t->kcov != NULL)
+			return -EBUSY;
+		remote_arg = (struct kcov_remote_arg *)arg;
+		mode = kcov_get_mode(remote_arg->trace_mode);
+		if (mode < 0)
+			return mode;
+		if (remote_arg->area_size > LONG_MAX / sizeof(unsigned long))
+			return -EINVAL;
+		kcov->mode = mode;
+		t->kcov = kcov;
+		kcov->t = t;
+		kcov->remote = true;
+		kcov->remote_size = remote_arg->area_size;
+		spin_lock_irqsave(&kcov_remote_lock, flags);
+		for (i = 0; i < remote_arg->num_handles; i++) {
+			if (!kcov_check_handle(remote_arg->handles[i],
+						false, true, false)) {
+				spin_unlock_irqrestore(&kcov_remote_lock,
+							flags);
+				kcov_disable(t, kcov);
+				return -EINVAL;
+			}
+			remote = kcov_remote_add(kcov, remote_arg->handles[i]);
+			if (IS_ERR(remote)) {
+				spin_unlock_irqrestore(&kcov_remote_lock,
+							flags);
+				kcov_disable(t, kcov);
+				return PTR_ERR(remote);
+			}
+		}
+		if (remote_arg->common_handle) {
+			if (!kcov_check_handle(remote_arg->common_handle,
+						true, false, false)) {
+				spin_unlock_irqrestore(&kcov_remote_lock,
+							flags);
+				kcov_disable(t, kcov);
+				return -EINVAL;
+			}
+			remote = kcov_remote_add(kcov,
+					remote_arg->common_handle);
+			if (IS_ERR(remote)) {
+				spin_unlock_irqrestore(&kcov_remote_lock,
+							flags);
+				kcov_disable(t, kcov);
+				return PTR_ERR(remote);
+			}
+			t->kcov_handle = remote_arg->common_handle;
+		}
+		spin_unlock_irqrestore(&kcov_remote_lock, flags);
+		/* Put either in kcov_task_exit() or in KCOV_DISABLE. */
+		kcov_get(kcov);
+		return 0;
+	default:
+		return -ENOTTY;
+	}
+}
+
+static long kcov_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
+{
+	struct kcov *kcov;
+	int res;
+	struct kcov_remote_arg *remote_arg = NULL;
+	unsigned int remote_num_handles;
+	unsigned long remote_arg_size;
+	unsigned long size, flags;
+	void *area;
+
+	kcov = filep->private_data;
+	switch (cmd) {
+	case KCOV_INIT_TRACE:
+		/*
+		 * Enable kcov in trace mode and setup buffer size.
+		 * Must happen before anything else.
+		 *
+		 * First check the size argument - it must be at least 2
+		 * to hold the current position and one PC.
+		 */
+		size = arg;
+		if (size < 2 || size > INT_MAX / sizeof(unsigned long))
+			return -EINVAL;
+		area = vmalloc_user(size * sizeof(unsigned long));
+		if (area == NULL)
+			return -ENOMEM;
+		spin_lock_irqsave(&kcov->lock, flags);
+		if (kcov->mode != KCOV_MODE_DISABLED) {
+			spin_unlock_irqrestore(&kcov->lock, flags);
+			vfree(area);
+			return -EBUSY;
+		}
+		kcov->area = area;
+		kcov->size = size;
+		kcov->mode = KCOV_MODE_INIT;
+		spin_unlock_irqrestore(&kcov->lock, flags);
+		return 0;
+	case KCOV_REMOTE_ENABLE:
+		if (get_user(remote_num_handles, (unsigned __user *)(arg +
+				offsetof(struct kcov_remote_arg, num_handles))))
+			return -EFAULT;
+		if (remote_num_handles > KCOV_REMOTE_MAX_HANDLES)
+			return -EINVAL;
+		remote_arg_size = struct_size(remote_arg, handles,
+					remote_num_handles);
+		remote_arg = memdup_user((void __user *)arg, remote_arg_size);
+		if (IS_ERR(remote_arg))
+			return PTR_ERR(remote_arg);
+		if (remote_arg->num_handles != remote_num_handles) {
+			kfree(remote_arg);
+			return -EINVAL;
+		}
+		arg = (unsigned long)remote_arg;
+		fallthrough;
+	default:
+		/*
+		 * All other commands can be normally executed under a spin lock, so we
+		 * obtain and release it here in order to simplify kcov_ioctl_locked().
+		 */
+		spin_lock_irqsave(&kcov->lock, flags);
+		res = kcov_ioctl_locked(kcov, cmd, arg);
+		spin_unlock_irqrestore(&kcov->lock, flags);
+		kfree(remote_arg);
+		return res;
+	}
+}
+
+static const struct file_operations kcov_fops = {
+	.open		= kcov_open,
+	.unlocked_ioctl	= kcov_ioctl,
+	.compat_ioctl	= kcov_ioctl,
+	.mmap		= kcov_mmap,
+	.release        = kcov_close,
+};
+
+/*
+ * kcov_remote_start() and kcov_remote_stop() can be used to annotate a section
+ * of code in a kernel background thread or in a softirq to allow kcov to be
+ * used to collect coverage from that part of code.
+ *
+ * The handle argument of kcov_remote_start() identifies a code section that is
+ * used for coverage collection. A userspace process passes this handle to
+ * KCOV_REMOTE_ENABLE ioctl to make the used kcov device start collecting
+ * coverage for the code section identified by this handle.
+ *
+ * The usage of these annotations in the kernel code is different depending on
+ * the type of the kernel thread whose code is being annotated.
+ *
+ * For global kernel threads that are spawned in a limited number of instances
+ * (e.g. one USB hub_event() worker thread is spawned per USB HCD) and for
+ * softirqs, each instance must be assigned a unique 4-byte instance id. The
+ * instance id is then combined with a 1-byte subsystem id to get a handle via
+ * kcov_remote_handle(subsystem_id, instance_id).
+ *
+ * For local kernel threads that are spawned from system calls handler when a
+ * user interacts with some kernel interface (e.g. vhost workers), a handle is
+ * passed from a userspace process as the common_handle field of the
+ * kcov_remote_arg struct (note, that the user must generate a handle by using
+ * kcov_remote_handle() with KCOV_SUBSYSTEM_COMMON as the subsystem id and an
+ * arbitrary 4-byte non-zero number as the instance id). This common handle
+ * then gets saved into the task_struct of the process that issued the
+ * KCOV_REMOTE_ENABLE ioctl. When this process issues system calls that spawn
+ * kernel threads, the common handle must be retrieved via kcov_common_handle()
+ * and passed to the spawned threads via custom annotations. Those kernel
+ * threads must in turn be annotated with kcov_remote_start(common_handle) and
+ * kcov_remote_stop(). All of the threads that are spawned by the same process
+ * obtain the same handle, hence the name "common".
+ *
+ * See Documentation/dev-tools/kcov.rst for more details.
+ *
+ * Internally, kcov_remote_start() looks up the kcov device associated with the
+ * provided handle, allocates an area for coverage collection, and saves the
+ * pointers to kcov and area into the current task_struct to allow coverage to
+ * be collected via __sanitizer_cov_trace_pc().
+ * In turns kcov_remote_stop() clears those pointers from task_struct to stop
+ * collecting coverage and copies all collected coverage into the kcov area.
+ */
+
+static inline bool kcov_mode_enabled(unsigned int mode)
+{
+	return (mode & ~KCOV_IN_CTXSW) != KCOV_MODE_DISABLED;
+}
+
+static void kcov_remote_softirq_start(struct task_struct *t)
+{
+	struct kcov_percpu_data *data = this_cpu_ptr(&kcov_percpu_data);
+	unsigned int mode;
+
+	mode = READ_ONCE(t->kcov_mode);
+	barrier();
+	if (kcov_mode_enabled(mode)) {
+		data->saved_mode = mode;
+		data->saved_size = t->kcov_size;
+		data->saved_area = t->kcov_area;
+		data->saved_sequence = t->kcov_sequence;
+		data->saved_kcov = t->kcov;
+		kcov_stop(t);
+	}
+}
+
+static void kcov_remote_softirq_stop(struct task_struct *t)
+{
+	struct kcov_percpu_data *data = this_cpu_ptr(&kcov_percpu_data);
+
+	if (data->saved_kcov) {
+		kcov_start(t, data->saved_kcov, data->saved_size,
+				data->saved_area, data->saved_mode,
+				data->saved_sequence);
+		data->saved_mode = 0;
+		data->saved_size = 0;
+		data->saved_area = NULL;
+		data->saved_sequence = 0;
+		data->saved_kcov = NULL;
+	}
+}
+
+void kcov_remote_start(u64 handle)
+{
+	struct task_struct *t = current;
+	struct kcov_remote *remote;
+	struct kcov *kcov;
+	unsigned int mode;
+	void *area;
+	unsigned int size;
+	int sequence;
+	unsigned long flags;
+
+	if (WARN_ON(!kcov_check_handle(handle, true, true, true)))
+		return;
+	if (!in_task() && !in_serving_softirq())
+		return;
+
+	local_lock_irqsave(&kcov_percpu_data.lock, flags);
+
+	/*
+	 * Check that kcov_remote_start() is not called twice in background
+	 * threads nor called by user tasks (with enabled kcov).
+	 */
+	mode = READ_ONCE(t->kcov_mode);
+	if (WARN_ON(in_task() && kcov_mode_enabled(mode))) {
+		local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
+		return;
+	}
+	/*
+	 * Check that kcov_remote_start() is not called twice in softirqs.
+	 * Note, that kcov_remote_start() can be called from a softirq that
+	 * happened while collecting coverage from a background thread.
+	 */
+	if (WARN_ON(in_serving_softirq() && t->kcov_softirq)) {
+		local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
+		return;
+	}
+
+	spin_lock(&kcov_remote_lock);
+	remote = kcov_remote_find(handle);
+	if (!remote) {
+		spin_unlock(&kcov_remote_lock);
+		local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
+		return;
+	}
+	kcov_debug("handle = %llx, context: %s\n", handle,
+			in_task() ? "task" : "softirq");
+	kcov = remote->kcov;
+	/* Put in kcov_remote_stop(). */
+	kcov_get(kcov);
+	/*
+	 * Read kcov fields before unlock to prevent races with
+	 * KCOV_DISABLE / kcov_remote_reset().
+	 */
+	mode = kcov->mode;
+	sequence = kcov->sequence;
+	if (in_task()) {
+		size = kcov->remote_size;
+		area = kcov_remote_area_get(size);
+	} else {
+		size = CONFIG_KCOV_IRQ_AREA_SIZE;
+		area = this_cpu_ptr(&kcov_percpu_data)->irq_area;
+	}
+	spin_unlock(&kcov_remote_lock);
+
+	/* Can only happen when in_task(). */
+	if (!area) {
+		local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
+		area = vmalloc(size * sizeof(unsigned long));
+		if (!area) {
+			kcov_put(kcov);
+			return;
+		}
+		local_lock_irqsave(&kcov_percpu_data.lock, flags);
+	}
+
+	/* Reset coverage size. */
+	*(u64 *)area = 0;
+
+	if (in_serving_softirq()) {
+		kcov_remote_softirq_start(t);
+		t->kcov_softirq = 1;
+	}
+	kcov_start(t, kcov, size, area, mode, sequence);
+
+	local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
+
+}
+EXPORT_SYMBOL(kcov_remote_start);
+
+static void kcov_move_area(enum kcov_mode mode, void *dst_area,
+				unsigned int dst_area_size, void *src_area)
+{
+	u64 word_size = sizeof(unsigned long);
+	u64 count_size, entry_size_log;
+	u64 dst_len, src_len;
+	void *dst_entries, *src_entries;
+	u64 dst_occupied, dst_free, bytes_to_move, entries_moved;
+
+	kcov_debug("%px %u <= %px %lu\n",
+		dst_area, dst_area_size, src_area, *(unsigned long *)src_area);
+
+	switch (mode) {
+	case KCOV_MODE_TRACE_PC:
+		dst_len = READ_ONCE(*(unsigned long *)dst_area);
+		src_len = *(unsigned long *)src_area;
+		count_size = sizeof(unsigned long);
+		entry_size_log = __ilog2_u64(sizeof(unsigned long));
+		break;
+	case KCOV_MODE_TRACE_CMP:
+		dst_len = READ_ONCE(*(u64 *)dst_area);
+		src_len = *(u64 *)src_area;
+		count_size = sizeof(u64);
+		BUILD_BUG_ON(!is_power_of_2(KCOV_WORDS_PER_CMP));
+		entry_size_log = __ilog2_u64(sizeof(u64) * KCOV_WORDS_PER_CMP);
+		break;
+	default:
+		WARN_ON(1);
+		return;
+	}
+
+	/* As arm can't divide u64 integers use log of entry size. */
+	if (dst_len > ((dst_area_size * word_size - count_size) >>
+				entry_size_log))
+		return;
+	dst_occupied = count_size + (dst_len << entry_size_log);
+	dst_free = dst_area_size * word_size - dst_occupied;
+	bytes_to_move = min(dst_free, src_len << entry_size_log);
+	dst_entries = dst_area + dst_occupied;
+	src_entries = src_area + count_size;
+	memcpy(dst_entries, src_entries, bytes_to_move);
+	entries_moved = bytes_to_move >> entry_size_log;
+
+	switch (mode) {
+	case KCOV_MODE_TRACE_PC:
+		WRITE_ONCE(*(unsigned long *)dst_area, dst_len + entries_moved);
+		break;
+	case KCOV_MODE_TRACE_CMP:
+		WRITE_ONCE(*(u64 *)dst_area, dst_len + entries_moved);
+		break;
+	default:
+		break;
+	}
+}
+
+/* See the comment before kcov_remote_start() for usage details. */
+void kcov_remote_stop(void)
+{
+	struct task_struct *t = current;
+	struct kcov *kcov;
+	unsigned int mode;
+	void *area;
+	unsigned int size;
+	int sequence;
+	unsigned long flags;
+
+	if (!in_task() && !in_serving_softirq())
+		return;
+
+	local_lock_irqsave(&kcov_percpu_data.lock, flags);
+
+	mode = READ_ONCE(t->kcov_mode);
+	barrier();
+	if (!kcov_mode_enabled(mode)) {
+		local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
+		return;
+	}
+	/*
+	 * When in softirq, check if the corresponding kcov_remote_start()
+	 * actually found the remote handle and started collecting coverage.
+	 */
+	if (in_serving_softirq() && !t->kcov_softirq) {
+		local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
+		return;
+	}
+	/* Make sure that kcov_softirq is only set when in softirq. */
+	if (WARN_ON(!in_serving_softirq() && t->kcov_softirq)) {
+		local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
+		return;
+	}
+
+	kcov = t->kcov;
+	area = t->kcov_area;
+	size = t->kcov_size;
+	sequence = t->kcov_sequence;
+
+	kcov_stop(t);
+	if (in_serving_softirq()) {
+		t->kcov_softirq = 0;
+		kcov_remote_softirq_stop(t);
+	}
+
+	spin_lock(&kcov->lock);
+	/*
+	 * KCOV_DISABLE could have been called between kcov_remote_start()
+	 * and kcov_remote_stop(), hence the sequence check.
+	 */
+	if (sequence == kcov->sequence && kcov->remote)
+		kcov_move_area(kcov->mode, kcov->area, kcov->size, area);
+	spin_unlock(&kcov->lock);
+
+	if (in_task()) {
+		spin_lock(&kcov_remote_lock);
+		kcov_remote_area_put(area, size);
+		spin_unlock(&kcov_remote_lock);
+	}
+
+	local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
+
+	/* Get in kcov_remote_start(). */
+	kcov_put(kcov);
+}
+EXPORT_SYMBOL(kcov_remote_stop);
+
+/* See the comment before kcov_remote_start() for usage details. */
+u64 kcov_common_handle(void)
+{
+	if (!in_task())
+		return 0;
+	return current->kcov_handle;
+}
+EXPORT_SYMBOL(kcov_common_handle);
+
+static int __init kcov_init(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		void *area = vmalloc_node(CONFIG_KCOV_IRQ_AREA_SIZE *
+				sizeof(unsigned long), cpu_to_node(cpu));
+		if (!area)
+			return -ENOMEM;
+		per_cpu_ptr(&kcov_percpu_data, cpu)->irq_area = area;
+	}
+
+	/*
+	 * The kcov debugfs file won't ever get removed and thus,
+	 * there is no need to protect it against removal races. The
+	 * use of debugfs_create_file_unsafe() is actually safe here.
+	 */
+	debugfs_create_file_unsafe("kcov", 0600, NULL, NULL, &kcov_fops);
+
+	return 0;
+}
+
+device_initcall(kcov_init);
diff --git a/kernel/kcsan/.kunitconfig b/kernel/kcsan/.kunitconfig
new file mode 100644
index 000000000..e82f0f52a
--- /dev/null
+++ b/kernel/kcsan/.kunitconfig
@@ -0,0 +1,24 @@
+# Note that the KCSAN tests need to run on an SMP setup.
+# Under kunit_tool, this can be done by using the --qemu_args
+# option to configure a machine with several cores. For example:
+# ./tools/testing/kunit/kunit.py run --kunitconfig=kernel/kcsan \
+# 				 --arch=x86_64 --qemu_args="-smp 8"
+
+CONFIG_KUNIT=y
+
+CONFIG_DEBUG_KERNEL=y
+
+# Need some level of concurrency to test a concurrency sanitizer.
+CONFIG_SMP=y
+
+CONFIG_KCSAN=y
+CONFIG_KCSAN_KUNIT_TEST=y
+
+# Set these if you want to run test_barrier_nothreads
+#CONFIG_KCSAN_STRICT=y
+#CONFIG_KCSAN_WEAK_MEMORY=y
+
+# This prevents the test from timing out on many setups. Feel free to remove
+# (or alter) this, in conjunction with setting a different test timeout with,
+# for example, the --timeout kunit_tool option.
+CONFIG_KCSAN_REPORT_ONCE_IN_MS=100
diff --git a/kernel/kcsan/Makefile b/kernel/kcsan/Makefile
new file mode 100644
index 000000000..a45f3dfc8
--- /dev/null
+++ b/kernel/kcsan/Makefile
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0
+KCSAN_SANITIZE := n
+KCOV_INSTRUMENT := n
+UBSAN_SANITIZE := n
+
+CFLAGS_REMOVE_core.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_debugfs.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE)
+
+CFLAGS_core.o := $(call cc-option,-fno-conserve-stack) \
+	$(call cc-option,-mno-outline-atomics) \
+	-fno-stack-protector -DDISABLE_BRANCH_PROFILING
+
+obj-y := core.o debugfs.o report.o
+
+KCSAN_INSTRUMENT_BARRIERS_selftest.o := y
+obj-$(CONFIG_KCSAN_SELFTEST) += selftest.o
+
+CFLAGS_kcsan_test.o := $(CFLAGS_KCSAN) -fno-omit-frame-pointer
+CFLAGS_kcsan_test.o += $(DISABLE_STRUCTLEAK_PLUGIN)
+obj-$(CONFIG_KCSAN_KUNIT_TEST) += kcsan_test.o
diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c
new file mode 100644
index 000000000..8a7baf4e3
--- /dev/null
+++ b/kernel/kcsan/core.c
@@ -0,0 +1,1371 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KCSAN core runtime.
+ *
+ * Copyright (C) 2019, Google LLC.
+ */
+
+#define pr_fmt(fmt) "kcsan: " fmt
+
+#include <linux/atomic.h>
+#include <linux/bug.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/minmax.h>
+#include <linux/moduleparam.h>
+#include <linux/percpu.h>
+#include <linux/preempt.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+
+#include "encoding.h"
+#include "kcsan.h"
+#include "permissive.h"
+
+static bool kcsan_early_enable = IS_ENABLED(CONFIG_KCSAN_EARLY_ENABLE);
+unsigned int kcsan_udelay_task = CONFIG_KCSAN_UDELAY_TASK;
+unsigned int kcsan_udelay_interrupt = CONFIG_KCSAN_UDELAY_INTERRUPT;
+static long kcsan_skip_watch = CONFIG_KCSAN_SKIP_WATCH;
+static bool kcsan_interrupt_watcher = IS_ENABLED(CONFIG_KCSAN_INTERRUPT_WATCHER);
+
+#ifdef MODULE_PARAM_PREFIX
+#undef MODULE_PARAM_PREFIX
+#endif
+#define MODULE_PARAM_PREFIX "kcsan."
+module_param_named(early_enable, kcsan_early_enable, bool, 0);
+module_param_named(udelay_task, kcsan_udelay_task, uint, 0644);
+module_param_named(udelay_interrupt, kcsan_udelay_interrupt, uint, 0644);
+module_param_named(skip_watch, kcsan_skip_watch, long, 0644);
+module_param_named(interrupt_watcher, kcsan_interrupt_watcher, bool, 0444);
+
+#ifdef CONFIG_KCSAN_WEAK_MEMORY
+static bool kcsan_weak_memory = true;
+module_param_named(weak_memory, kcsan_weak_memory, bool, 0644);
+#else
+#define kcsan_weak_memory false
+#endif
+
+bool kcsan_enabled;
+
+/* Per-CPU kcsan_ctx for interrupts */
+static DEFINE_PER_CPU(struct kcsan_ctx, kcsan_cpu_ctx) = {
+	.scoped_accesses	= {LIST_POISON1, NULL},
+};
+
+/*
+ * Helper macros to index into adjacent slots, starting from address slot
+ * itself, followed by the right and left slots.
+ *
+ * The purpose is 2-fold:
+ *
+ *	1. if during insertion the address slot is already occupied, check if
+ *	   any adjacent slots are free;
+ *	2. accesses that straddle a slot boundary due to size that exceeds a
+ *	   slot's range may check adjacent slots if any watchpoint matches.
+ *
+ * Note that accesses with very large size may still miss a watchpoint; however,
+ * given this should be rare, this is a reasonable trade-off to make, since this
+ * will avoid:
+ *
+ *	1. excessive contention between watchpoint checks and setup;
+ *	2. larger number of simultaneous watchpoints without sacrificing
+ *	   performance.
+ *
+ * Example: SLOT_IDX values for KCSAN_CHECK_ADJACENT=1, where i is [0, 1, 2]:
+ *
+ *   slot=0:  [ 1,  2,  0]
+ *   slot=9:  [10, 11,  9]
+ *   slot=63: [64, 65, 63]
+ */
+#define SLOT_IDX(slot, i) (slot + ((i + KCSAN_CHECK_ADJACENT) % NUM_SLOTS))
+
+/*
+ * SLOT_IDX_FAST is used in the fast-path. Not first checking the address's primary
+ * slot (middle) is fine if we assume that races occur rarely. The set of
+ * indices {SLOT_IDX(slot, i) | i in [0, NUM_SLOTS)} is equivalent to
+ * {SLOT_IDX_FAST(slot, i) | i in [0, NUM_SLOTS)}.
+ */
+#define SLOT_IDX_FAST(slot, i) (slot + i)
+
+/*
+ * Watchpoints, with each entry encoded as defined in encoding.h: in order to be
+ * able to safely update and access a watchpoint without introducing locking
+ * overhead, we encode each watchpoint as a single atomic long. The initial
+ * zero-initialized state matches INVALID_WATCHPOINT.
+ *
+ * Add NUM_SLOTS-1 entries to account for overflow; this helps avoid having to
+ * use more complicated SLOT_IDX_FAST calculation with modulo in the fast-path.
+ */
+static atomic_long_t watchpoints[CONFIG_KCSAN_NUM_WATCHPOINTS + NUM_SLOTS-1];
+
+/*
+ * Instructions to skip watching counter, used in should_watch(). We use a
+ * per-CPU counter to avoid excessive contention.
+ */
+static DEFINE_PER_CPU(long, kcsan_skip);
+
+/* For kcsan_prandom_u32_max(). */
+static DEFINE_PER_CPU(u32, kcsan_rand_state);
+
+static __always_inline atomic_long_t *find_watchpoint(unsigned long addr,
+						      size_t size,
+						      bool expect_write,
+						      long *encoded_watchpoint)
+{
+	const int slot = watchpoint_slot(addr);
+	const unsigned long addr_masked = addr & WATCHPOINT_ADDR_MASK;
+	atomic_long_t *watchpoint;
+	unsigned long wp_addr_masked;
+	size_t wp_size;
+	bool is_write;
+	int i;
+
+	BUILD_BUG_ON(CONFIG_KCSAN_NUM_WATCHPOINTS < NUM_SLOTS);
+
+	for (i = 0; i < NUM_SLOTS; ++i) {
+		watchpoint = &watchpoints[SLOT_IDX_FAST(slot, i)];
+		*encoded_watchpoint = atomic_long_read(watchpoint);
+		if (!decode_watchpoint(*encoded_watchpoint, &wp_addr_masked,
+				       &wp_size, &is_write))
+			continue;
+
+		if (expect_write && !is_write)
+			continue;
+
+		/* Check if the watchpoint matches the access. */
+		if (matching_access(wp_addr_masked, wp_size, addr_masked, size))
+			return watchpoint;
+	}
+
+	return NULL;
+}
+
+static inline atomic_long_t *
+insert_watchpoint(unsigned long addr, size_t size, bool is_write)
+{
+	const int slot = watchpoint_slot(addr);
+	const long encoded_watchpoint = encode_watchpoint(addr, size, is_write);
+	atomic_long_t *watchpoint;
+	int i;
+
+	/* Check slot index logic, ensuring we stay within array bounds. */
+	BUILD_BUG_ON(SLOT_IDX(0, 0) != KCSAN_CHECK_ADJACENT);
+	BUILD_BUG_ON(SLOT_IDX(0, KCSAN_CHECK_ADJACENT+1) != 0);
+	BUILD_BUG_ON(SLOT_IDX(CONFIG_KCSAN_NUM_WATCHPOINTS-1, KCSAN_CHECK_ADJACENT) != ARRAY_SIZE(watchpoints)-1);
+	BUILD_BUG_ON(SLOT_IDX(CONFIG_KCSAN_NUM_WATCHPOINTS-1, KCSAN_CHECK_ADJACENT+1) != ARRAY_SIZE(watchpoints) - NUM_SLOTS);
+
+	for (i = 0; i < NUM_SLOTS; ++i) {
+		long expect_val = INVALID_WATCHPOINT;
+
+		/* Try to acquire this slot. */
+		watchpoint = &watchpoints[SLOT_IDX(slot, i)];
+		if (atomic_long_try_cmpxchg_relaxed(watchpoint, &expect_val, encoded_watchpoint))
+			return watchpoint;
+	}
+
+	return NULL;
+}
+
+/*
+ * Return true if watchpoint was successfully consumed, false otherwise.
+ *
+ * This may return false if:
+ *
+ *	1. another thread already consumed the watchpoint;
+ *	2. the thread that set up the watchpoint already removed it;
+ *	3. the watchpoint was removed and then re-used.
+ */
+static __always_inline bool
+try_consume_watchpoint(atomic_long_t *watchpoint, long encoded_watchpoint)
+{
+	return atomic_long_try_cmpxchg_relaxed(watchpoint, &encoded_watchpoint, CONSUMED_WATCHPOINT);
+}
+
+/* Return true if watchpoint was not touched, false if already consumed. */
+static inline bool consume_watchpoint(atomic_long_t *watchpoint)
+{
+	return atomic_long_xchg_relaxed(watchpoint, CONSUMED_WATCHPOINT) != CONSUMED_WATCHPOINT;
+}
+
+/* Remove the watchpoint -- its slot may be reused after. */
+static inline void remove_watchpoint(atomic_long_t *watchpoint)
+{
+	atomic_long_set(watchpoint, INVALID_WATCHPOINT);
+}
+
+static __always_inline struct kcsan_ctx *get_ctx(void)
+{
+	/*
+	 * In interrupts, use raw_cpu_ptr to avoid unnecessary checks, that would
+	 * also result in calls that generate warnings in uaccess regions.
+	 */
+	return in_task() ? &current->kcsan_ctx : raw_cpu_ptr(&kcsan_cpu_ctx);
+}
+
+static __always_inline void
+check_access(const volatile void *ptr, size_t size, int type, unsigned long ip);
+
+/* Check scoped accesses; never inline because this is a slow-path! */
+static noinline void kcsan_check_scoped_accesses(void)
+{
+	struct kcsan_ctx *ctx = get_ctx();
+	struct kcsan_scoped_access *scoped_access;
+
+	if (ctx->disable_scoped)
+		return;
+
+	ctx->disable_scoped++;
+	list_for_each_entry(scoped_access, &ctx->scoped_accesses, list) {
+		check_access(scoped_access->ptr, scoped_access->size,
+			     scoped_access->type, scoped_access->ip);
+	}
+	ctx->disable_scoped--;
+}
+
+/* Rules for generic atomic accesses. Called from fast-path. */
+static __always_inline bool
+is_atomic(struct kcsan_ctx *ctx, const volatile void *ptr, size_t size, int type)
+{
+	if (type & KCSAN_ACCESS_ATOMIC)
+		return true;
+
+	/*
+	 * Unless explicitly declared atomic, never consider an assertion access
+	 * as atomic. This allows using them also in atomic regions, such as
+	 * seqlocks, without implicitly changing their semantics.
+	 */
+	if (type & KCSAN_ACCESS_ASSERT)
+		return false;
+
+	if (IS_ENABLED(CONFIG_KCSAN_ASSUME_PLAIN_WRITES_ATOMIC) &&
+	    (type & KCSAN_ACCESS_WRITE) && size <= sizeof(long) &&
+	    !(type & KCSAN_ACCESS_COMPOUND) && IS_ALIGNED((unsigned long)ptr, size))
+		return true; /* Assume aligned writes up to word size are atomic. */
+
+	if (ctx->atomic_next > 0) {
+		/*
+		 * Because we do not have separate contexts for nested
+		 * interrupts, in case atomic_next is set, we simply assume that
+		 * the outer interrupt set atomic_next. In the worst case, we
+		 * will conservatively consider operations as atomic. This is a
+		 * reasonable trade-off to make, since this case should be
+		 * extremely rare; however, even if extremely rare, it could
+		 * lead to false positives otherwise.
+		 */
+		if ((hardirq_count() >> HARDIRQ_SHIFT) < 2)
+			--ctx->atomic_next; /* in task, or outer interrupt */
+		return true;
+	}
+
+	return ctx->atomic_nest_count > 0 || ctx->in_flat_atomic;
+}
+
+static __always_inline bool
+should_watch(struct kcsan_ctx *ctx, const volatile void *ptr, size_t size, int type)
+{
+	/*
+	 * Never set up watchpoints when memory operations are atomic.
+	 *
+	 * Need to check this first, before kcsan_skip check below: (1) atomics
+	 * should not count towards skipped instructions, and (2) to actually
+	 * decrement kcsan_atomic_next for consecutive instruction stream.
+	 */
+	if (is_atomic(ctx, ptr, size, type))
+		return false;
+
+	if (this_cpu_dec_return(kcsan_skip) >= 0)
+		return false;
+
+	/*
+	 * NOTE: If we get here, kcsan_skip must always be reset in slow path
+	 * via reset_kcsan_skip() to avoid underflow.
+	 */
+
+	/* this operation should be watched */
+	return true;
+}
+
+/*
+ * Returns a pseudo-random number in interval [0, ep_ro). Simple linear
+ * congruential generator, using constants from "Numerical Recipes".
+ */
+static u32 kcsan_prandom_u32_max(u32 ep_ro)
+{
+	u32 state = this_cpu_read(kcsan_rand_state);
+
+	state = 1664525 * state + 1013904223;
+	this_cpu_write(kcsan_rand_state, state);
+
+	return state % ep_ro;
+}
+
+static inline void reset_kcsan_skip(void)
+{
+	long skip_count = kcsan_skip_watch -
+			  (IS_ENABLED(CONFIG_KCSAN_SKIP_WATCH_RANDOMIZE) ?
+				   kcsan_prandom_u32_max(kcsan_skip_watch) :
+				   0);
+	this_cpu_write(kcsan_skip, skip_count);
+}
+
+static __always_inline bool kcsan_is_enabled(struct kcsan_ctx *ctx)
+{
+	return READ_ONCE(kcsan_enabled) && !ctx->disable_count;
+}
+
+/* Introduce delay depending on context and configuration. */
+static void delay_access(int type)
+{
+	unsigned int delay = in_task() ? kcsan_udelay_task : kcsan_udelay_interrupt;
+	/* For certain access types, skew the random delay to be longer. */
+	unsigned int skew_delay_order =
+		(type & (KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_ASSERT)) ? 1 : 0;
+
+	delay -= IS_ENABLED(CONFIG_KCSAN_DELAY_RANDOMIZE) ?
+			       kcsan_prandom_u32_max(delay >> skew_delay_order) :
+			       0;
+	udelay(delay);
+}
+
+/*
+ * Reads the instrumented memory for value change detection; value change
+ * detection is currently done for accesses up to a size of 8 bytes.
+ */
+static __always_inline u64 read_instrumented_memory(const volatile void *ptr, size_t size)
+{
+	/*
+	 * In the below we don't necessarily need the read of the location to
+	 * be atomic, and we don't use READ_ONCE(), since all we need for race
+	 * detection is to observe 2 different values.
+	 *
+	 * Furthermore, on certain architectures (such as arm64), READ_ONCE()
+	 * may turn into more complex instructions than a plain load that cannot
+	 * do unaligned accesses.
+	 */
+	switch (size) {
+	case 1:  return *(const volatile u8 *)ptr;
+	case 2:  return *(const volatile u16 *)ptr;
+	case 4:  return *(const volatile u32 *)ptr;
+	case 8:  return *(const volatile u64 *)ptr;
+	default: return 0; /* Ignore; we do not diff the values. */
+	}
+}
+
+void kcsan_save_irqtrace(struct task_struct *task)
+{
+#ifdef CONFIG_TRACE_IRQFLAGS
+	task->kcsan_save_irqtrace = task->irqtrace;
+#endif
+}
+
+void kcsan_restore_irqtrace(struct task_struct *task)
+{
+#ifdef CONFIG_TRACE_IRQFLAGS
+	task->irqtrace = task->kcsan_save_irqtrace;
+#endif
+}
+
+static __always_inline int get_kcsan_stack_depth(void)
+{
+#ifdef CONFIG_KCSAN_WEAK_MEMORY
+	return current->kcsan_stack_depth;
+#else
+	BUILD_BUG();
+	return 0;
+#endif
+}
+
+static __always_inline void add_kcsan_stack_depth(int val)
+{
+#ifdef CONFIG_KCSAN_WEAK_MEMORY
+	current->kcsan_stack_depth += val;
+#else
+	BUILD_BUG();
+#endif
+}
+
+static __always_inline struct kcsan_scoped_access *get_reorder_access(struct kcsan_ctx *ctx)
+{
+#ifdef CONFIG_KCSAN_WEAK_MEMORY
+	return ctx->disable_scoped ? NULL : &ctx->reorder_access;
+#else
+	return NULL;
+#endif
+}
+
+static __always_inline bool
+find_reorder_access(struct kcsan_ctx *ctx, const volatile void *ptr, size_t size,
+		    int type, unsigned long ip)
+{
+	struct kcsan_scoped_access *reorder_access = get_reorder_access(ctx);
+
+	if (!reorder_access)
+		return false;
+
+	/*
+	 * Note: If accesses are repeated while reorder_access is identical,
+	 * never matches the new access, because !(type & KCSAN_ACCESS_SCOPED).
+	 */
+	return reorder_access->ptr == ptr && reorder_access->size == size &&
+	       reorder_access->type == type && reorder_access->ip == ip;
+}
+
+static inline void
+set_reorder_access(struct kcsan_ctx *ctx, const volatile void *ptr, size_t size,
+		   int type, unsigned long ip)
+{
+	struct kcsan_scoped_access *reorder_access = get_reorder_access(ctx);
+
+	if (!reorder_access || !kcsan_weak_memory)
+		return;
+
+	/*
+	 * To avoid nested interrupts or scheduler (which share kcsan_ctx)
+	 * reading an inconsistent reorder_access, ensure that the below has
+	 * exclusive access to reorder_access by disallowing concurrent use.
+	 */
+	ctx->disable_scoped++;
+	barrier();
+	reorder_access->ptr		= ptr;
+	reorder_access->size		= size;
+	reorder_access->type		= type | KCSAN_ACCESS_SCOPED;
+	reorder_access->ip		= ip;
+	reorder_access->stack_depth	= get_kcsan_stack_depth();
+	barrier();
+	ctx->disable_scoped--;
+}
+
+/*
+ * Pull everything together: check_access() below contains the performance
+ * critical operations; the fast-path (including check_access) functions should
+ * all be inlinable by the instrumentation functions.
+ *
+ * The slow-path (kcsan_found_watchpoint, kcsan_setup_watchpoint) are
+ * non-inlinable -- note that, we prefix these with "kcsan_" to ensure they can
+ * be filtered from the stacktrace, as well as give them unique names for the
+ * UACCESS whitelist of objtool. Each function uses user_access_save/restore(),
+ * since they do not access any user memory, but instrumentation is still
+ * emitted in UACCESS regions.
+ */
+
+static noinline void kcsan_found_watchpoint(const volatile void *ptr,
+					    size_t size,
+					    int type,
+					    unsigned long ip,
+					    atomic_long_t *watchpoint,
+					    long encoded_watchpoint)
+{
+	const bool is_assert = (type & KCSAN_ACCESS_ASSERT) != 0;
+	struct kcsan_ctx *ctx = get_ctx();
+	unsigned long flags;
+	bool consumed;
+
+	/*
+	 * We know a watchpoint exists. Let's try to keep the race-window
+	 * between here and finally consuming the watchpoint below as small as
+	 * possible -- avoid unneccessarily complex code until consumed.
+	 */
+
+	if (!kcsan_is_enabled(ctx))
+		return;
+
+	/*
+	 * The access_mask check relies on value-change comparison. To avoid
+	 * reporting a race where e.g. the writer set up the watchpoint, but the
+	 * reader has access_mask!=0, we have to ignore the found watchpoint.
+	 *
+	 * reorder_access is never created from an access with access_mask set.
+	 */
+	if (ctx->access_mask && !find_reorder_access(ctx, ptr, size, type, ip))
+		return;
+
+	/*
+	 * If the other thread does not want to ignore the access, and there was
+	 * a value change as a result of this thread's operation, we will still
+	 * generate a report of unknown origin.
+	 *
+	 * Use CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN=n to filter.
+	 */
+	if (!is_assert && kcsan_ignore_address(ptr))
+		return;
+
+	/*
+	 * Consuming the watchpoint must be guarded by kcsan_is_enabled() to
+	 * avoid erroneously triggering reports if the context is disabled.
+	 */
+	consumed = try_consume_watchpoint(watchpoint, encoded_watchpoint);
+
+	/* keep this after try_consume_watchpoint */
+	flags = user_access_save();
+
+	if (consumed) {
+		kcsan_save_irqtrace(current);
+		kcsan_report_set_info(ptr, size, type, ip, watchpoint - watchpoints);
+		kcsan_restore_irqtrace(current);
+	} else {
+		/*
+		 * The other thread may not print any diagnostics, as it has
+		 * already removed the watchpoint, or another thread consumed
+		 * the watchpoint before this thread.
+		 */
+		atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_REPORT_RACES]);
+	}
+
+	if (is_assert)
+		atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_ASSERT_FAILURES]);
+	else
+		atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_DATA_RACES]);
+
+	user_access_restore(flags);
+}
+
+static noinline void
+kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type, unsigned long ip)
+{
+	const bool is_write = (type & KCSAN_ACCESS_WRITE) != 0;
+	const bool is_assert = (type & KCSAN_ACCESS_ASSERT) != 0;
+	atomic_long_t *watchpoint;
+	u64 old, new, diff;
+	enum kcsan_value_change value_change = KCSAN_VALUE_CHANGE_MAYBE;
+	bool interrupt_watcher = kcsan_interrupt_watcher;
+	unsigned long ua_flags = user_access_save();
+	struct kcsan_ctx *ctx = get_ctx();
+	unsigned long access_mask = ctx->access_mask;
+	unsigned long irq_flags = 0;
+	bool is_reorder_access;
+
+	/*
+	 * Always reset kcsan_skip counter in slow-path to avoid underflow; see
+	 * should_watch().
+	 */
+	reset_kcsan_skip();
+
+	if (!kcsan_is_enabled(ctx))
+		goto out;
+
+	/*
+	 * Check to-ignore addresses after kcsan_is_enabled(), as we may access
+	 * memory that is not yet initialized during early boot.
+	 */
+	if (!is_assert && kcsan_ignore_address(ptr))
+		goto out;
+
+	if (!check_encodable((unsigned long)ptr, size)) {
+		atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_UNENCODABLE_ACCESSES]);
+		goto out;
+	}
+
+	/*
+	 * The local CPU cannot observe reordering of its own accesses, and
+	 * therefore we need to take care of 2 cases to avoid false positives:
+	 *
+	 *	1. Races of the reordered access with interrupts. To avoid, if
+	 *	   the current access is reorder_access, disable interrupts.
+	 *	2. Avoid races of scoped accesses from nested interrupts (below).
+	 */
+	is_reorder_access = find_reorder_access(ctx, ptr, size, type, ip);
+	if (is_reorder_access)
+		interrupt_watcher = false;
+	/*
+	 * Avoid races of scoped accesses from nested interrupts (or scheduler).
+	 * Assume setting up a watchpoint for a non-scoped (normal) access that
+	 * also conflicts with a current scoped access. In a nested interrupt,
+	 * which shares the context, it would check a conflicting scoped access.
+	 * To avoid, disable scoped access checking.
+	 */
+	ctx->disable_scoped++;
+
+	/*
+	 * Save and restore the IRQ state trace touched by KCSAN, since KCSAN's
+	 * runtime is entered for every memory access, and potentially useful
+	 * information is lost if dirtied by KCSAN.
+	 */
+	kcsan_save_irqtrace(current);
+	if (!interrupt_watcher)
+		local_irq_save(irq_flags);
+
+	watchpoint = insert_watchpoint((unsigned long)ptr, size, is_write);
+	if (watchpoint == NULL) {
+		/*
+		 * Out of capacity: the size of 'watchpoints', and the frequency
+		 * with which should_watch() returns true should be tweaked so
+		 * that this case happens very rarely.
+		 */
+		atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_NO_CAPACITY]);
+		goto out_unlock;
+	}
+
+	atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_SETUP_WATCHPOINTS]);
+	atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_USED_WATCHPOINTS]);
+
+	/*
+	 * Read the current value, to later check and infer a race if the data
+	 * was modified via a non-instrumented access, e.g. from a device.
+	 */
+	old = is_reorder_access ? 0 : read_instrumented_memory(ptr, size);
+
+	/*
+	 * Delay this thread, to increase probability of observing a racy
+	 * conflicting access.
+	 */
+	delay_access(type);
+
+	/*
+	 * Re-read value, and check if it is as expected; if not, we infer a
+	 * racy access.
+	 */
+	if (!is_reorder_access) {
+		new = read_instrumented_memory(ptr, size);
+	} else {
+		/*
+		 * Reordered accesses cannot be used for value change detection,
+		 * because the memory location may no longer be accessible and
+		 * could result in a fault.
+		 */
+		new = 0;
+		access_mask = 0;
+	}
+
+	diff = old ^ new;
+	if (access_mask)
+		diff &= access_mask;
+
+	/*
+	 * Check if we observed a value change.
+	 *
+	 * Also check if the data race should be ignored (the rules depend on
+	 * non-zero diff); if it is to be ignored, the below rules for
+	 * KCSAN_VALUE_CHANGE_MAYBE apply.
+	 */
+	if (diff && !kcsan_ignore_data_race(size, type, old, new, diff))
+		value_change = KCSAN_VALUE_CHANGE_TRUE;
+
+	/* Check if this access raced with another. */
+	if (!consume_watchpoint(watchpoint)) {
+		/*
+		 * Depending on the access type, map a value_change of MAYBE to
+		 * TRUE (always report) or FALSE (never report).
+		 */
+		if (value_change == KCSAN_VALUE_CHANGE_MAYBE) {
+			if (access_mask != 0) {
+				/*
+				 * For access with access_mask, we require a
+				 * value-change, as it is likely that races on
+				 * ~access_mask bits are expected.
+				 */
+				value_change = KCSAN_VALUE_CHANGE_FALSE;
+			} else if (size > 8 || is_assert) {
+				/* Always assume a value-change. */
+				value_change = KCSAN_VALUE_CHANGE_TRUE;
+			}
+		}
+
+		/*
+		 * No need to increment 'data_races' counter, as the racing
+		 * thread already did.
+		 *
+		 * Count 'assert_failures' for each failed ASSERT access,
+		 * therefore both this thread and the racing thread may
+		 * increment this counter.
+		 */
+		if (is_assert && value_change == KCSAN_VALUE_CHANGE_TRUE)
+			atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_ASSERT_FAILURES]);
+
+		kcsan_report_known_origin(ptr, size, type, ip,
+					  value_change, watchpoint - watchpoints,
+					  old, new, access_mask);
+	} else if (value_change == KCSAN_VALUE_CHANGE_TRUE) {
+		/* Inferring a race, since the value should not have changed. */
+
+		atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN]);
+		if (is_assert)
+			atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_ASSERT_FAILURES]);
+
+		if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN) || is_assert) {
+			kcsan_report_unknown_origin(ptr, size, type, ip,
+						    old, new, access_mask);
+		}
+	}
+
+	/*
+	 * Remove watchpoint; must be after reporting, since the slot may be
+	 * reused after this point.
+	 */
+	remove_watchpoint(watchpoint);
+	atomic_long_dec(&kcsan_counters[KCSAN_COUNTER_USED_WATCHPOINTS]);
+
+out_unlock:
+	if (!interrupt_watcher)
+		local_irq_restore(irq_flags);
+	kcsan_restore_irqtrace(current);
+	ctx->disable_scoped--;
+
+	/*
+	 * Reordered accesses cannot be used for value change detection,
+	 * therefore never consider for reordering if access_mask is set.
+	 * ASSERT_EXCLUSIVE are not real accesses, ignore them as well.
+	 */
+	if (!access_mask && !is_assert)
+		set_reorder_access(ctx, ptr, size, type, ip);
+out:
+	user_access_restore(ua_flags);
+}
+
+static __always_inline void
+check_access(const volatile void *ptr, size_t size, int type, unsigned long ip)
+{
+	atomic_long_t *watchpoint;
+	long encoded_watchpoint;
+
+	/*
+	 * Do nothing for 0 sized check; this comparison will be optimized out
+	 * for constant sized instrumentation (__tsan_{read,write}N).
+	 */
+	if (unlikely(size == 0))
+		return;
+
+again:
+	/*
+	 * Avoid user_access_save in fast-path: find_watchpoint is safe without
+	 * user_access_save, as the address that ptr points to is only used to
+	 * check if a watchpoint exists; ptr is never dereferenced.
+	 */
+	watchpoint = find_watchpoint((unsigned long)ptr, size,
+				     !(type & KCSAN_ACCESS_WRITE),
+				     &encoded_watchpoint);
+	/*
+	 * It is safe to check kcsan_is_enabled() after find_watchpoint in the
+	 * slow-path, as long as no state changes that cause a race to be
+	 * detected and reported have occurred until kcsan_is_enabled() is
+	 * checked.
+	 */
+
+	if (unlikely(watchpoint != NULL))
+		kcsan_found_watchpoint(ptr, size, type, ip, watchpoint, encoded_watchpoint);
+	else {
+		struct kcsan_ctx *ctx = get_ctx(); /* Call only once in fast-path. */
+
+		if (unlikely(should_watch(ctx, ptr, size, type))) {
+			kcsan_setup_watchpoint(ptr, size, type, ip);
+			return;
+		}
+
+		if (!(type & KCSAN_ACCESS_SCOPED)) {
+			struct kcsan_scoped_access *reorder_access = get_reorder_access(ctx);
+
+			if (reorder_access) {
+				/*
+				 * reorder_access check: simulates reordering of
+				 * the access after subsequent operations.
+				 */
+				ptr = reorder_access->ptr;
+				type = reorder_access->type;
+				ip = reorder_access->ip;
+				/*
+				 * Upon a nested interrupt, this context's
+				 * reorder_access can be modified (shared ctx).
+				 * We know that upon return, reorder_access is
+				 * always invalidated by setting size to 0 via
+				 * __tsan_func_exit(). Therefore we must read
+				 * and check size after the other fields.
+				 */
+				barrier();
+				size = READ_ONCE(reorder_access->size);
+				if (size)
+					goto again;
+			}
+		}
+
+		/*
+		 * Always checked last, right before returning from runtime;
+		 * if reorder_access is valid, checked after it was checked.
+		 */
+		if (unlikely(ctx->scoped_accesses.prev))
+			kcsan_check_scoped_accesses();
+	}
+}
+
+/* === Public interface ===================================================== */
+
+void __init kcsan_init(void)
+{
+	int cpu;
+
+	BUG_ON(!in_task());
+
+	for_each_possible_cpu(cpu)
+		per_cpu(kcsan_rand_state, cpu) = (u32)get_cycles();
+
+	/*
+	 * We are in the init task, and no other tasks should be running;
+	 * WRITE_ONCE without memory barrier is sufficient.
+	 */
+	if (kcsan_early_enable) {
+		pr_info("enabled early\n");
+		WRITE_ONCE(kcsan_enabled, true);
+	}
+
+	if (IS_ENABLED(CONFIG_KCSAN_REPORT_VALUE_CHANGE_ONLY) ||
+	    IS_ENABLED(CONFIG_KCSAN_ASSUME_PLAIN_WRITES_ATOMIC) ||
+	    IS_ENABLED(CONFIG_KCSAN_PERMISSIVE) ||
+	    IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) {
+		pr_warn("non-strict mode configured - use CONFIG_KCSAN_STRICT=y to see all data races\n");
+	} else {
+		pr_info("strict mode configured\n");
+	}
+}
+
+/* === Exported interface =================================================== */
+
+void kcsan_disable_current(void)
+{
+	++get_ctx()->disable_count;
+}
+EXPORT_SYMBOL(kcsan_disable_current);
+
+void kcsan_enable_current(void)
+{
+	if (get_ctx()->disable_count-- == 0) {
+		/*
+		 * Warn if kcsan_enable_current() calls are unbalanced with
+		 * kcsan_disable_current() calls, which causes disable_count to
+		 * become negative and should not happen.
+		 */
+		kcsan_disable_current(); /* restore to 0, KCSAN still enabled */
+		kcsan_disable_current(); /* disable to generate warning */
+		WARN(1, "Unbalanced %s()", __func__);
+		kcsan_enable_current();
+	}
+}
+EXPORT_SYMBOL(kcsan_enable_current);
+
+void kcsan_enable_current_nowarn(void)
+{
+	if (get_ctx()->disable_count-- == 0)
+		kcsan_disable_current();
+}
+EXPORT_SYMBOL(kcsan_enable_current_nowarn);
+
+void kcsan_nestable_atomic_begin(void)
+{
+	/*
+	 * Do *not* check and warn if we are in a flat atomic region: nestable
+	 * and flat atomic regions are independent from each other.
+	 * See include/linux/kcsan.h: struct kcsan_ctx comments for more
+	 * comments.
+	 */
+
+	++get_ctx()->atomic_nest_count;
+}
+EXPORT_SYMBOL(kcsan_nestable_atomic_begin);
+
+void kcsan_nestable_atomic_end(void)
+{
+	if (get_ctx()->atomic_nest_count-- == 0) {
+		/*
+		 * Warn if kcsan_nestable_atomic_end() calls are unbalanced with
+		 * kcsan_nestable_atomic_begin() calls, which causes
+		 * atomic_nest_count to become negative and should not happen.
+		 */
+		kcsan_nestable_atomic_begin(); /* restore to 0 */
+		kcsan_disable_current(); /* disable to generate warning */
+		WARN(1, "Unbalanced %s()", __func__);
+		kcsan_enable_current();
+	}
+}
+EXPORT_SYMBOL(kcsan_nestable_atomic_end);
+
+void kcsan_flat_atomic_begin(void)
+{
+	get_ctx()->in_flat_atomic = true;
+}
+EXPORT_SYMBOL(kcsan_flat_atomic_begin);
+
+void kcsan_flat_atomic_end(void)
+{
+	get_ctx()->in_flat_atomic = false;
+}
+EXPORT_SYMBOL(kcsan_flat_atomic_end);
+
+void kcsan_atomic_next(int n)
+{
+	get_ctx()->atomic_next = n;
+}
+EXPORT_SYMBOL(kcsan_atomic_next);
+
+void kcsan_set_access_mask(unsigned long mask)
+{
+	get_ctx()->access_mask = mask;
+}
+EXPORT_SYMBOL(kcsan_set_access_mask);
+
+struct kcsan_scoped_access *
+kcsan_begin_scoped_access(const volatile void *ptr, size_t size, int type,
+			  struct kcsan_scoped_access *sa)
+{
+	struct kcsan_ctx *ctx = get_ctx();
+
+	check_access(ptr, size, type, _RET_IP_);
+
+	ctx->disable_count++; /* Disable KCSAN, in case list debugging is on. */
+
+	INIT_LIST_HEAD(&sa->list);
+	sa->ptr = ptr;
+	sa->size = size;
+	sa->type = type;
+	sa->ip = _RET_IP_;
+
+	if (!ctx->scoped_accesses.prev) /* Lazy initialize list head. */
+		INIT_LIST_HEAD(&ctx->scoped_accesses);
+	list_add(&sa->list, &ctx->scoped_accesses);
+
+	ctx->disable_count--;
+	return sa;
+}
+EXPORT_SYMBOL(kcsan_begin_scoped_access);
+
+void kcsan_end_scoped_access(struct kcsan_scoped_access *sa)
+{
+	struct kcsan_ctx *ctx = get_ctx();
+
+	if (WARN(!ctx->scoped_accesses.prev, "Unbalanced %s()?", __func__))
+		return;
+
+	ctx->disable_count++; /* Disable KCSAN, in case list debugging is on. */
+
+	list_del(&sa->list);
+	if (list_empty(&ctx->scoped_accesses))
+		/*
+		 * Ensure we do not enter kcsan_check_scoped_accesses()
+		 * slow-path if unnecessary, and avoids requiring list_empty()
+		 * in the fast-path (to avoid a READ_ONCE() and potential
+		 * uaccess warning).
+		 */
+		ctx->scoped_accesses.prev = NULL;
+
+	ctx->disable_count--;
+
+	check_access(sa->ptr, sa->size, sa->type, sa->ip);
+}
+EXPORT_SYMBOL(kcsan_end_scoped_access);
+
+void __kcsan_check_access(const volatile void *ptr, size_t size, int type)
+{
+	check_access(ptr, size, type, _RET_IP_);
+}
+EXPORT_SYMBOL(__kcsan_check_access);
+
+#define DEFINE_MEMORY_BARRIER(name, order_before_cond)				\
+	void __kcsan_##name(void)						\
+	{									\
+		struct kcsan_scoped_access *sa = get_reorder_access(get_ctx());	\
+		if (!sa)							\
+			return;							\
+		if (order_before_cond)						\
+			sa->size = 0;						\
+	}									\
+	EXPORT_SYMBOL(__kcsan_##name)
+
+DEFINE_MEMORY_BARRIER(mb, true);
+DEFINE_MEMORY_BARRIER(wmb, sa->type & (KCSAN_ACCESS_WRITE | KCSAN_ACCESS_COMPOUND));
+DEFINE_MEMORY_BARRIER(rmb, !(sa->type & KCSAN_ACCESS_WRITE) || (sa->type & KCSAN_ACCESS_COMPOUND));
+DEFINE_MEMORY_BARRIER(release, true);
+
+/*
+ * KCSAN uses the same instrumentation that is emitted by supported compilers
+ * for ThreadSanitizer (TSAN).
+ *
+ * When enabled, the compiler emits instrumentation calls (the functions
+ * prefixed with "__tsan" below) for all loads and stores that it generated;
+ * inline asm is not instrumented.
+ *
+ * Note that, not all supported compiler versions distinguish aligned/unaligned
+ * accesses, but e.g. recent versions of Clang do. We simply alias the unaligned
+ * version to the generic version, which can handle both.
+ */
+
+#define DEFINE_TSAN_READ_WRITE(size)                                           \
+	void __tsan_read##size(void *ptr);                                     \
+	void __tsan_read##size(void *ptr)                                      \
+	{                                                                      \
+		check_access(ptr, size, 0, _RET_IP_);                          \
+	}                                                                      \
+	EXPORT_SYMBOL(__tsan_read##size);                                      \
+	void __tsan_unaligned_read##size(void *ptr)                            \
+		__alias(__tsan_read##size);                                    \
+	EXPORT_SYMBOL(__tsan_unaligned_read##size);                            \
+	void __tsan_write##size(void *ptr);                                    \
+	void __tsan_write##size(void *ptr)                                     \
+	{                                                                      \
+		check_access(ptr, size, KCSAN_ACCESS_WRITE, _RET_IP_);         \
+	}                                                                      \
+	EXPORT_SYMBOL(__tsan_write##size);                                     \
+	void __tsan_unaligned_write##size(void *ptr)                           \
+		__alias(__tsan_write##size);                                   \
+	EXPORT_SYMBOL(__tsan_unaligned_write##size);                           \
+	void __tsan_read_write##size(void *ptr);                               \
+	void __tsan_read_write##size(void *ptr)                                \
+	{                                                                      \
+		check_access(ptr, size,                                        \
+			     KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE,       \
+			     _RET_IP_);                                        \
+	}                                                                      \
+	EXPORT_SYMBOL(__tsan_read_write##size);                                \
+	void __tsan_unaligned_read_write##size(void *ptr)                      \
+		__alias(__tsan_read_write##size);                              \
+	EXPORT_SYMBOL(__tsan_unaligned_read_write##size)
+
+DEFINE_TSAN_READ_WRITE(1);
+DEFINE_TSAN_READ_WRITE(2);
+DEFINE_TSAN_READ_WRITE(4);
+DEFINE_TSAN_READ_WRITE(8);
+DEFINE_TSAN_READ_WRITE(16);
+
+void __tsan_read_range(void *ptr, size_t size);
+void __tsan_read_range(void *ptr, size_t size)
+{
+	check_access(ptr, size, 0, _RET_IP_);
+}
+EXPORT_SYMBOL(__tsan_read_range);
+
+void __tsan_write_range(void *ptr, size_t size);
+void __tsan_write_range(void *ptr, size_t size)
+{
+	check_access(ptr, size, KCSAN_ACCESS_WRITE, _RET_IP_);
+}
+EXPORT_SYMBOL(__tsan_write_range);
+
+/*
+ * Use of explicit volatile is generally disallowed [1], however, volatile is
+ * still used in various concurrent context, whether in low-level
+ * synchronization primitives or for legacy reasons.
+ * [1] https://lwn.net/Articles/233479/
+ *
+ * We only consider volatile accesses atomic if they are aligned and would pass
+ * the size-check of compiletime_assert_rwonce_type().
+ */
+#define DEFINE_TSAN_VOLATILE_READ_WRITE(size)                                  \
+	void __tsan_volatile_read##size(void *ptr);                            \
+	void __tsan_volatile_read##size(void *ptr)                             \
+	{                                                                      \
+		const bool is_atomic = size <= sizeof(long long) &&            \
+				       IS_ALIGNED((unsigned long)ptr, size);   \
+		if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS) && is_atomic)      \
+			return;                                                \
+		check_access(ptr, size, is_atomic ? KCSAN_ACCESS_ATOMIC : 0,   \
+			     _RET_IP_);                                        \
+	}                                                                      \
+	EXPORT_SYMBOL(__tsan_volatile_read##size);                             \
+	void __tsan_unaligned_volatile_read##size(void *ptr)                   \
+		__alias(__tsan_volatile_read##size);                           \
+	EXPORT_SYMBOL(__tsan_unaligned_volatile_read##size);                   \
+	void __tsan_volatile_write##size(void *ptr);                           \
+	void __tsan_volatile_write##size(void *ptr)                            \
+	{                                                                      \
+		const bool is_atomic = size <= sizeof(long long) &&            \
+				       IS_ALIGNED((unsigned long)ptr, size);   \
+		if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS) && is_atomic)      \
+			return;                                                \
+		check_access(ptr, size,                                        \
+			     KCSAN_ACCESS_WRITE |                              \
+				     (is_atomic ? KCSAN_ACCESS_ATOMIC : 0),    \
+			     _RET_IP_);                                        \
+	}                                                                      \
+	EXPORT_SYMBOL(__tsan_volatile_write##size);                            \
+	void __tsan_unaligned_volatile_write##size(void *ptr)                  \
+		__alias(__tsan_volatile_write##size);                          \
+	EXPORT_SYMBOL(__tsan_unaligned_volatile_write##size)
+
+DEFINE_TSAN_VOLATILE_READ_WRITE(1);
+DEFINE_TSAN_VOLATILE_READ_WRITE(2);
+DEFINE_TSAN_VOLATILE_READ_WRITE(4);
+DEFINE_TSAN_VOLATILE_READ_WRITE(8);
+DEFINE_TSAN_VOLATILE_READ_WRITE(16);
+
+/*
+ * Function entry and exit are used to determine the validty of reorder_access.
+ * Reordering of the access ends at the end of the function scope where the
+ * access happened. This is done for two reasons:
+ *
+ *	1. Artificially limits the scope where missing barriers are detected.
+ *	   This minimizes false positives due to uninstrumented functions that
+ *	   contain the required barriers but were missed.
+ *
+ *	2. Simplifies generating the stack trace of the access.
+ */
+void __tsan_func_entry(void *call_pc);
+noinline void __tsan_func_entry(void *call_pc)
+{
+	if (!IS_ENABLED(CONFIG_KCSAN_WEAK_MEMORY))
+		return;
+
+	add_kcsan_stack_depth(1);
+}
+EXPORT_SYMBOL(__tsan_func_entry);
+
+void __tsan_func_exit(void);
+noinline void __tsan_func_exit(void)
+{
+	struct kcsan_scoped_access *reorder_access;
+
+	if (!IS_ENABLED(CONFIG_KCSAN_WEAK_MEMORY))
+		return;
+
+	reorder_access = get_reorder_access(get_ctx());
+	if (!reorder_access)
+		goto out;
+
+	if (get_kcsan_stack_depth() <= reorder_access->stack_depth) {
+		/*
+		 * Access check to catch cases where write without a barrier
+		 * (supposed release) was last access in function: because
+		 * instrumentation is inserted before the real access, a data
+		 * race due to the write giving up a c-s would only be caught if
+		 * we do the conflicting access after.
+		 */
+		check_access(reorder_access->ptr, reorder_access->size,
+			     reorder_access->type, reorder_access->ip);
+		reorder_access->size = 0;
+		reorder_access->stack_depth = INT_MIN;
+	}
+out:
+	add_kcsan_stack_depth(-1);
+}
+EXPORT_SYMBOL(__tsan_func_exit);
+
+void __tsan_init(void);
+void __tsan_init(void)
+{
+}
+EXPORT_SYMBOL(__tsan_init);
+
+/*
+ * Instrumentation for atomic builtins (__atomic_*, __sync_*).
+ *
+ * Normal kernel code _should not_ be using them directly, but some
+ * architectures may implement some or all atomics using the compilers'
+ * builtins.
+ *
+ * Note: If an architecture decides to fully implement atomics using the
+ * builtins, because they are implicitly instrumented by KCSAN (and KASAN,
+ * etc.), implementing the ARCH_ATOMIC interface (to get instrumentation via
+ * atomic-instrumented) is no longer necessary.
+ *
+ * TSAN instrumentation replaces atomic accesses with calls to any of the below
+ * functions, whose job is to also execute the operation itself.
+ */
+
+static __always_inline void kcsan_atomic_builtin_memorder(int memorder)
+{
+	if (memorder == __ATOMIC_RELEASE ||
+	    memorder == __ATOMIC_SEQ_CST ||
+	    memorder == __ATOMIC_ACQ_REL)
+		__kcsan_release();
+}
+
+#define DEFINE_TSAN_ATOMIC_LOAD_STORE(bits)                                                        \
+	u##bits __tsan_atomic##bits##_load(const u##bits *ptr, int memorder);                      \
+	u##bits __tsan_atomic##bits##_load(const u##bits *ptr, int memorder)                       \
+	{                                                                                          \
+		kcsan_atomic_builtin_memorder(memorder);                                           \
+		if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) {                                    \
+			check_access(ptr, bits / BITS_PER_BYTE, KCSAN_ACCESS_ATOMIC, _RET_IP_);    \
+		}                                                                                  \
+		return __atomic_load_n(ptr, memorder);                                             \
+	}                                                                                          \
+	EXPORT_SYMBOL(__tsan_atomic##bits##_load);                                                 \
+	void __tsan_atomic##bits##_store(u##bits *ptr, u##bits v, int memorder);                   \
+	void __tsan_atomic##bits##_store(u##bits *ptr, u##bits v, int memorder)                    \
+	{                                                                                          \
+		kcsan_atomic_builtin_memorder(memorder);                                           \
+		if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) {                                    \
+			check_access(ptr, bits / BITS_PER_BYTE,                                    \
+				     KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC, _RET_IP_);          \
+		}                                                                                  \
+		__atomic_store_n(ptr, v, memorder);                                                \
+	}                                                                                          \
+	EXPORT_SYMBOL(__tsan_atomic##bits##_store)
+
+#define DEFINE_TSAN_ATOMIC_RMW(op, bits, suffix)                                                   \
+	u##bits __tsan_atomic##bits##_##op(u##bits *ptr, u##bits v, int memorder);                 \
+	u##bits __tsan_atomic##bits##_##op(u##bits *ptr, u##bits v, int memorder)                  \
+	{                                                                                          \
+		kcsan_atomic_builtin_memorder(memorder);                                           \
+		if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) {                                    \
+			check_access(ptr, bits / BITS_PER_BYTE,                                    \
+				     KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE |                  \
+					     KCSAN_ACCESS_ATOMIC, _RET_IP_);                       \
+		}                                                                                  \
+		return __atomic_##op##suffix(ptr, v, memorder);                                    \
+	}                                                                                          \
+	EXPORT_SYMBOL(__tsan_atomic##bits##_##op)
+
+/*
+ * Note: CAS operations are always classified as write, even in case they
+ * fail. We cannot perform check_access() after a write, as it might lead to
+ * false positives, in cases such as:
+ *
+ *	T0: __atomic_compare_exchange_n(&p->flag, &old, 1, ...)
+ *
+ *	T1: if (__atomic_load_n(&p->flag, ...)) {
+ *		modify *p;
+ *		p->flag = 0;
+ *	    }
+ *
+ * The only downside is that, if there are 3 threads, with one CAS that
+ * succeeds, another CAS that fails, and an unmarked racing operation, we may
+ * point at the wrong CAS as the source of the race. However, if we assume that
+ * all CAS can succeed in some other execution, the data race is still valid.
+ */
+#define DEFINE_TSAN_ATOMIC_CMPXCHG(bits, strength, weak)                                           \
+	int __tsan_atomic##bits##_compare_exchange_##strength(u##bits *ptr, u##bits *exp,          \
+							      u##bits val, int mo, int fail_mo);   \
+	int __tsan_atomic##bits##_compare_exchange_##strength(u##bits *ptr, u##bits *exp,          \
+							      u##bits val, int mo, int fail_mo)    \
+	{                                                                                          \
+		kcsan_atomic_builtin_memorder(mo);                                                 \
+		if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) {                                    \
+			check_access(ptr, bits / BITS_PER_BYTE,                                    \
+				     KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE |                  \
+					     KCSAN_ACCESS_ATOMIC, _RET_IP_);                       \
+		}                                                                                  \
+		return __atomic_compare_exchange_n(ptr, exp, val, weak, mo, fail_mo);              \
+	}                                                                                          \
+	EXPORT_SYMBOL(__tsan_atomic##bits##_compare_exchange_##strength)
+
+#define DEFINE_TSAN_ATOMIC_CMPXCHG_VAL(bits)                                                       \
+	u##bits __tsan_atomic##bits##_compare_exchange_val(u##bits *ptr, u##bits exp, u##bits val, \
+							   int mo, int fail_mo);                   \
+	u##bits __tsan_atomic##bits##_compare_exchange_val(u##bits *ptr, u##bits exp, u##bits val, \
+							   int mo, int fail_mo)                    \
+	{                                                                                          \
+		kcsan_atomic_builtin_memorder(mo);                                                 \
+		if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) {                                    \
+			check_access(ptr, bits / BITS_PER_BYTE,                                    \
+				     KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE |                  \
+					     KCSAN_ACCESS_ATOMIC, _RET_IP_);                       \
+		}                                                                                  \
+		__atomic_compare_exchange_n(ptr, &exp, val, 0, mo, fail_mo);                       \
+		return exp;                                                                        \
+	}                                                                                          \
+	EXPORT_SYMBOL(__tsan_atomic##bits##_compare_exchange_val)
+
+#define DEFINE_TSAN_ATOMIC_OPS(bits)                                                               \
+	DEFINE_TSAN_ATOMIC_LOAD_STORE(bits);                                                       \
+	DEFINE_TSAN_ATOMIC_RMW(exchange, bits, _n);                                                \
+	DEFINE_TSAN_ATOMIC_RMW(fetch_add, bits, );                                                 \
+	DEFINE_TSAN_ATOMIC_RMW(fetch_sub, bits, );                                                 \
+	DEFINE_TSAN_ATOMIC_RMW(fetch_and, bits, );                                                 \
+	DEFINE_TSAN_ATOMIC_RMW(fetch_or, bits, );                                                  \
+	DEFINE_TSAN_ATOMIC_RMW(fetch_xor, bits, );                                                 \
+	DEFINE_TSAN_ATOMIC_RMW(fetch_nand, bits, );                                                \
+	DEFINE_TSAN_ATOMIC_CMPXCHG(bits, strong, 0);                                               \
+	DEFINE_TSAN_ATOMIC_CMPXCHG(bits, weak, 1);                                                 \
+	DEFINE_TSAN_ATOMIC_CMPXCHG_VAL(bits)
+
+DEFINE_TSAN_ATOMIC_OPS(8);
+DEFINE_TSAN_ATOMIC_OPS(16);
+DEFINE_TSAN_ATOMIC_OPS(32);
+#ifdef CONFIG_64BIT
+DEFINE_TSAN_ATOMIC_OPS(64);
+#endif
+
+void __tsan_atomic_thread_fence(int memorder);
+void __tsan_atomic_thread_fence(int memorder)
+{
+	kcsan_atomic_builtin_memorder(memorder);
+	__atomic_thread_fence(memorder);
+}
+EXPORT_SYMBOL(__tsan_atomic_thread_fence);
+
+/*
+ * In instrumented files, we emit instrumentation for barriers by mapping the
+ * kernel barriers to an __atomic_signal_fence(), which is interpreted specially
+ * and otherwise has no relation to a real __atomic_signal_fence(). No known
+ * kernel code uses __atomic_signal_fence().
+ *
+ * Since fsanitize=thread instrumentation handles __atomic_signal_fence(), which
+ * are turned into calls to __tsan_atomic_signal_fence(), such instrumentation
+ * can be disabled via the __no_kcsan function attribute (vs. an explicit call
+ * which could not). When __no_kcsan is requested, __atomic_signal_fence()
+ * generates no code.
+ *
+ * Note: The result of using __atomic_signal_fence() with KCSAN enabled is
+ * potentially limiting the compiler's ability to reorder operations; however,
+ * if barriers were instrumented with explicit calls (without LTO), the compiler
+ * couldn't optimize much anyway. The result of a hypothetical architecture
+ * using __atomic_signal_fence() in normal code would be KCSAN false negatives.
+ */
+void __tsan_atomic_signal_fence(int memorder);
+noinline void __tsan_atomic_signal_fence(int memorder)
+{
+	switch (memorder) {
+	case __KCSAN_BARRIER_TO_SIGNAL_FENCE_mb:
+		__kcsan_mb();
+		break;
+	case __KCSAN_BARRIER_TO_SIGNAL_FENCE_wmb:
+		__kcsan_wmb();
+		break;
+	case __KCSAN_BARRIER_TO_SIGNAL_FENCE_rmb:
+		__kcsan_rmb();
+		break;
+	case __KCSAN_BARRIER_TO_SIGNAL_FENCE_release:
+		__kcsan_release();
+		break;
+	default:
+		break;
+	}
+}
+EXPORT_SYMBOL(__tsan_atomic_signal_fence);
+
+#ifdef __HAVE_ARCH_MEMSET
+void *__tsan_memset(void *s, int c, size_t count);
+noinline void *__tsan_memset(void *s, int c, size_t count)
+{
+	/*
+	 * Instead of not setting up watchpoints where accessed size is greater
+	 * than MAX_ENCODABLE_SIZE, truncate checked size to MAX_ENCODABLE_SIZE.
+	 */
+	size_t check_len = min_t(size_t, count, MAX_ENCODABLE_SIZE);
+
+	check_access(s, check_len, KCSAN_ACCESS_WRITE, _RET_IP_);
+	return memset(s, c, count);
+}
+#else
+void *__tsan_memset(void *s, int c, size_t count) __alias(memset);
+#endif
+EXPORT_SYMBOL(__tsan_memset);
+
+#ifdef __HAVE_ARCH_MEMMOVE
+void *__tsan_memmove(void *dst, const void *src, size_t len);
+noinline void *__tsan_memmove(void *dst, const void *src, size_t len)
+{
+	size_t check_len = min_t(size_t, len, MAX_ENCODABLE_SIZE);
+
+	check_access(dst, check_len, KCSAN_ACCESS_WRITE, _RET_IP_);
+	check_access(src, check_len, 0, _RET_IP_);
+	return memmove(dst, src, len);
+}
+#else
+void *__tsan_memmove(void *dst, const void *src, size_t len) __alias(memmove);
+#endif
+EXPORT_SYMBOL(__tsan_memmove);
+
+#ifdef __HAVE_ARCH_MEMCPY
+void *__tsan_memcpy(void *dst, const void *src, size_t len);
+noinline void *__tsan_memcpy(void *dst, const void *src, size_t len)
+{
+	size_t check_len = min_t(size_t, len, MAX_ENCODABLE_SIZE);
+
+	check_access(dst, check_len, KCSAN_ACCESS_WRITE, _RET_IP_);
+	check_access(src, check_len, 0, _RET_IP_);
+	return memcpy(dst, src, len);
+}
+#else
+void *__tsan_memcpy(void *dst, const void *src, size_t len) __alias(memcpy);
+#endif
+EXPORT_SYMBOL(__tsan_memcpy);
diff --git a/kernel/kcsan/debugfs.c b/kernel/kcsan/debugfs.c
new file mode 100644
index 000000000..1d1d1b0e4
--- /dev/null
+++ b/kernel/kcsan/debugfs.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KCSAN debugfs interface.
+ *
+ * Copyright (C) 2019, Google LLC.
+ */
+
+#define pr_fmt(fmt) "kcsan: " fmt
+
+#include <linux/atomic.h>
+#include <linux/bsearch.h>
+#include <linux/bug.h>
+#include <linux/debugfs.h>
+#include <linux/init.h>
+#include <linux/kallsyms.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+
+#include "kcsan.h"
+
+atomic_long_t kcsan_counters[KCSAN_COUNTER_COUNT];
+static const char *const counter_names[] = {
+	[KCSAN_COUNTER_USED_WATCHPOINTS]		= "used_watchpoints",
+	[KCSAN_COUNTER_SETUP_WATCHPOINTS]		= "setup_watchpoints",
+	[KCSAN_COUNTER_DATA_RACES]			= "data_races",
+	[KCSAN_COUNTER_ASSERT_FAILURES]			= "assert_failures",
+	[KCSAN_COUNTER_NO_CAPACITY]			= "no_capacity",
+	[KCSAN_COUNTER_REPORT_RACES]			= "report_races",
+	[KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN]		= "races_unknown_origin",
+	[KCSAN_COUNTER_UNENCODABLE_ACCESSES]		= "unencodable_accesses",
+	[KCSAN_COUNTER_ENCODING_FALSE_POSITIVES]	= "encoding_false_positives",
+};
+static_assert(ARRAY_SIZE(counter_names) == KCSAN_COUNTER_COUNT);
+
+/*
+ * Addresses for filtering functions from reporting. This list can be used as a
+ * whitelist or blacklist.
+ */
+static struct {
+	unsigned long	*addrs;		/* array of addresses */
+	size_t		size;		/* current size */
+	int		used;		/* number of elements used */
+	bool		sorted;		/* if elements are sorted */
+	bool		whitelist;	/* if list is a blacklist or whitelist */
+} report_filterlist = {
+	.addrs		= NULL,
+	.size		= 8,		/* small initial size */
+	.used		= 0,
+	.sorted		= false,
+	.whitelist	= false,	/* default is blacklist */
+};
+static DEFINE_SPINLOCK(report_filterlist_lock);
+
+/*
+ * The microbenchmark allows benchmarking KCSAN core runtime only. To run
+ * multiple threads, pipe 'microbench=<iters>' from multiple tasks into the
+ * debugfs file. This will not generate any conflicts, and tests fast-path only.
+ */
+static noinline void microbenchmark(unsigned long iters)
+{
+	const struct kcsan_ctx ctx_save = current->kcsan_ctx;
+	const bool was_enabled = READ_ONCE(kcsan_enabled);
+	u64 cycles;
+
+	/* We may have been called from an atomic region; reset context. */
+	memset(&current->kcsan_ctx, 0, sizeof(current->kcsan_ctx));
+	/*
+	 * Disable to benchmark fast-path for all accesses, and (expected
+	 * negligible) call into slow-path, but never set up watchpoints.
+	 */
+	WRITE_ONCE(kcsan_enabled, false);
+
+	pr_info("%s begin | iters: %lu\n", __func__, iters);
+
+	cycles = get_cycles();
+	while (iters--) {
+		unsigned long addr = iters & ((PAGE_SIZE << 8) - 1);
+		int type = !(iters & 0x7f) ? KCSAN_ACCESS_ATOMIC :
+				(!(iters & 0xf) ? KCSAN_ACCESS_WRITE : 0);
+		__kcsan_check_access((void *)addr, sizeof(long), type);
+	}
+	cycles = get_cycles() - cycles;
+
+	pr_info("%s end   | cycles: %llu\n", __func__, cycles);
+
+	WRITE_ONCE(kcsan_enabled, was_enabled);
+	/* restore context */
+	current->kcsan_ctx = ctx_save;
+}
+
+static int cmp_filterlist_addrs(const void *rhs, const void *lhs)
+{
+	const unsigned long a = *(const unsigned long *)rhs;
+	const unsigned long b = *(const unsigned long *)lhs;
+
+	return a < b ? -1 : a == b ? 0 : 1;
+}
+
+bool kcsan_skip_report_debugfs(unsigned long func_addr)
+{
+	unsigned long symbolsize, offset;
+	unsigned long flags;
+	bool ret = false;
+
+	if (!kallsyms_lookup_size_offset(func_addr, &symbolsize, &offset))
+		return false;
+	func_addr -= offset; /* Get function start */
+
+	spin_lock_irqsave(&report_filterlist_lock, flags);
+	if (report_filterlist.used == 0)
+		goto out;
+
+	/* Sort array if it is unsorted, and then do a binary search. */
+	if (!report_filterlist.sorted) {
+		sort(report_filterlist.addrs, report_filterlist.used,
+		     sizeof(unsigned long), cmp_filterlist_addrs, NULL);
+		report_filterlist.sorted = true;
+	}
+	ret = !!bsearch(&func_addr, report_filterlist.addrs,
+			report_filterlist.used, sizeof(unsigned long),
+			cmp_filterlist_addrs);
+	if (report_filterlist.whitelist)
+		ret = !ret;
+
+out:
+	spin_unlock_irqrestore(&report_filterlist_lock, flags);
+	return ret;
+}
+
+static void set_report_filterlist_whitelist(bool whitelist)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&report_filterlist_lock, flags);
+	report_filterlist.whitelist = whitelist;
+	spin_unlock_irqrestore(&report_filterlist_lock, flags);
+}
+
+/* Returns 0 on success, error-code otherwise. */
+static ssize_t insert_report_filterlist(const char *func)
+{
+	unsigned long flags;
+	unsigned long addr = kallsyms_lookup_name(func);
+	ssize_t ret = 0;
+
+	if (!addr) {
+		pr_err("could not find function: '%s'\n", func);
+		return -ENOENT;
+	}
+
+	spin_lock_irqsave(&report_filterlist_lock, flags);
+
+	if (report_filterlist.addrs == NULL) {
+		/* initial allocation */
+		report_filterlist.addrs =
+			kmalloc_array(report_filterlist.size,
+				      sizeof(unsigned long), GFP_ATOMIC);
+		if (report_filterlist.addrs == NULL) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	} else if (report_filterlist.used == report_filterlist.size) {
+		/* resize filterlist */
+		size_t new_size = report_filterlist.size * 2;
+		unsigned long *new_addrs =
+			krealloc(report_filterlist.addrs,
+				 new_size * sizeof(unsigned long), GFP_ATOMIC);
+
+		if (new_addrs == NULL) {
+			/* leave filterlist itself untouched */
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		report_filterlist.size = new_size;
+		report_filterlist.addrs = new_addrs;
+	}
+
+	/* Note: deduplicating should be done in userspace. */
+	report_filterlist.addrs[report_filterlist.used++] =
+		kallsyms_lookup_name(func);
+	report_filterlist.sorted = false;
+
+out:
+	spin_unlock_irqrestore(&report_filterlist_lock, flags);
+
+	return ret;
+}
+
+static int show_info(struct seq_file *file, void *v)
+{
+	int i;
+	unsigned long flags;
+
+	/* show stats */
+	seq_printf(file, "enabled: %i\n", READ_ONCE(kcsan_enabled));
+	for (i = 0; i < KCSAN_COUNTER_COUNT; ++i) {
+		seq_printf(file, "%s: %ld\n", counter_names[i],
+			   atomic_long_read(&kcsan_counters[i]));
+	}
+
+	/* show filter functions, and filter type */
+	spin_lock_irqsave(&report_filterlist_lock, flags);
+	seq_printf(file, "\n%s functions: %s\n",
+		   report_filterlist.whitelist ? "whitelisted" : "blacklisted",
+		   report_filterlist.used == 0 ? "none" : "");
+	for (i = 0; i < report_filterlist.used; ++i)
+		seq_printf(file, " %ps\n", (void *)report_filterlist.addrs[i]);
+	spin_unlock_irqrestore(&report_filterlist_lock, flags);
+
+	return 0;
+}
+
+static int debugfs_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, show_info, NULL);
+}
+
+static ssize_t
+debugfs_write(struct file *file, const char __user *buf, size_t count, loff_t *off)
+{
+	char kbuf[KSYM_NAME_LEN];
+	char *arg;
+	int read_len = count < (sizeof(kbuf) - 1) ? count : (sizeof(kbuf) - 1);
+
+	if (copy_from_user(kbuf, buf, read_len))
+		return -EFAULT;
+	kbuf[read_len] = '\0';
+	arg = strstrip(kbuf);
+
+	if (!strcmp(arg, "on")) {
+		WRITE_ONCE(kcsan_enabled, true);
+	} else if (!strcmp(arg, "off")) {
+		WRITE_ONCE(kcsan_enabled, false);
+	} else if (str_has_prefix(arg, "microbench=")) {
+		unsigned long iters;
+
+		if (kstrtoul(&arg[strlen("microbench=")], 0, &iters))
+			return -EINVAL;
+		microbenchmark(iters);
+	} else if (!strcmp(arg, "whitelist")) {
+		set_report_filterlist_whitelist(true);
+	} else if (!strcmp(arg, "blacklist")) {
+		set_report_filterlist_whitelist(false);
+	} else if (arg[0] == '!') {
+		ssize_t ret = insert_report_filterlist(&arg[1]);
+
+		if (ret < 0)
+			return ret;
+	} else {
+		return -EINVAL;
+	}
+
+	return count;
+}
+
+static const struct file_operations debugfs_ops =
+{
+	.read	 = seq_read,
+	.open	 = debugfs_open,
+	.write	 = debugfs_write,
+	.release = single_release
+};
+
+static int __init kcsan_debugfs_init(void)
+{
+	debugfs_create_file("kcsan", 0644, NULL, NULL, &debugfs_ops);
+	return 0;
+}
+
+late_initcall(kcsan_debugfs_init);
diff --git a/kernel/kcsan/encoding.h b/kernel/kcsan/encoding.h
new file mode 100644
index 000000000..170a2bb22
--- /dev/null
+++ b/kernel/kcsan/encoding.h
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * KCSAN watchpoint encoding.
+ *
+ * Copyright (C) 2019, Google LLC.
+ */
+
+#ifndef _KERNEL_KCSAN_ENCODING_H
+#define _KERNEL_KCSAN_ENCODING_H
+
+#include <linux/bits.h>
+#include <linux/log2.h>
+#include <linux/mm.h>
+
+#include "kcsan.h"
+
+#define SLOT_RANGE PAGE_SIZE
+
+#define INVALID_WATCHPOINT  0
+#define CONSUMED_WATCHPOINT 1
+
+/*
+ * The maximum useful size of accesses for which we set up watchpoints is the
+ * max range of slots we check on an access.
+ */
+#define MAX_ENCODABLE_SIZE (SLOT_RANGE * (1 + KCSAN_CHECK_ADJACENT))
+
+/*
+ * Number of bits we use to store size info.
+ */
+#define WATCHPOINT_SIZE_BITS bits_per(MAX_ENCODABLE_SIZE)
+/*
+ * This encoding for addresses discards the upper (1 for is-write + SIZE_BITS);
+ * however, most 64-bit architectures do not use the full 64-bit address space.
+ * Also, in order for a false positive to be observable 2 things need to happen:
+ *
+ *	1. different addresses but with the same encoded address race;
+ *	2. and both map onto the same watchpoint slots;
+ *
+ * Both these are assumed to be very unlikely. However, in case it still
+ * happens, the report logic will filter out the false positive (see report.c).
+ */
+#define WATCHPOINT_ADDR_BITS (BITS_PER_LONG-1 - WATCHPOINT_SIZE_BITS)
+
+/* Bitmasks for the encoded watchpoint access information. */
+#define WATCHPOINT_WRITE_MASK	BIT(BITS_PER_LONG-1)
+#define WATCHPOINT_SIZE_MASK	GENMASK(BITS_PER_LONG-2, WATCHPOINT_ADDR_BITS)
+#define WATCHPOINT_ADDR_MASK	GENMASK(WATCHPOINT_ADDR_BITS-1, 0)
+static_assert(WATCHPOINT_ADDR_MASK == (1UL << WATCHPOINT_ADDR_BITS) - 1);
+static_assert((WATCHPOINT_WRITE_MASK ^ WATCHPOINT_SIZE_MASK ^ WATCHPOINT_ADDR_MASK) == ~0UL);
+
+static inline bool check_encodable(unsigned long addr, size_t size)
+{
+	/*
+	 * While we can encode addrs<PAGE_SIZE, avoid crashing with a NULL
+	 * pointer deref inside KCSAN.
+	 */
+	return addr >= PAGE_SIZE && size <= MAX_ENCODABLE_SIZE;
+}
+
+static inline long
+encode_watchpoint(unsigned long addr, size_t size, bool is_write)
+{
+	return (long)((is_write ? WATCHPOINT_WRITE_MASK : 0) |
+		      (size << WATCHPOINT_ADDR_BITS) |
+		      (addr & WATCHPOINT_ADDR_MASK));
+}
+
+static __always_inline bool decode_watchpoint(long watchpoint,
+					      unsigned long *addr_masked,
+					      size_t *size,
+					      bool *is_write)
+{
+	if (watchpoint == INVALID_WATCHPOINT ||
+	    watchpoint == CONSUMED_WATCHPOINT)
+		return false;
+
+	*addr_masked =    (unsigned long)watchpoint & WATCHPOINT_ADDR_MASK;
+	*size	     =   ((unsigned long)watchpoint & WATCHPOINT_SIZE_MASK) >> WATCHPOINT_ADDR_BITS;
+	*is_write    = !!((unsigned long)watchpoint & WATCHPOINT_WRITE_MASK);
+
+	return true;
+}
+
+/*
+ * Return watchpoint slot for an address.
+ */
+static __always_inline int watchpoint_slot(unsigned long addr)
+{
+	return (addr / PAGE_SIZE) % CONFIG_KCSAN_NUM_WATCHPOINTS;
+}
+
+static __always_inline bool matching_access(unsigned long addr1, size_t size1,
+					    unsigned long addr2, size_t size2)
+{
+	unsigned long end_range1 = addr1 + size1 - 1;
+	unsigned long end_range2 = addr2 + size2 - 1;
+
+	return addr1 <= end_range2 && addr2 <= end_range1;
+}
+
+#endif /* _KERNEL_KCSAN_ENCODING_H */
diff --git a/kernel/kcsan/kcsan.h b/kernel/kcsan/kcsan.h
new file mode 100644
index 000000000..ae33c2a7f
--- /dev/null
+++ b/kernel/kcsan/kcsan.h
@@ -0,0 +1,142 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * The Kernel Concurrency Sanitizer (KCSAN) infrastructure. For more info please
+ * see Documentation/dev-tools/kcsan.rst.
+ *
+ * Copyright (C) 2019, Google LLC.
+ */
+
+#ifndef _KERNEL_KCSAN_KCSAN_H
+#define _KERNEL_KCSAN_KCSAN_H
+
+#include <linux/atomic.h>
+#include <linux/kcsan.h>
+#include <linux/sched.h>
+
+/* The number of adjacent watchpoints to check. */
+#define KCSAN_CHECK_ADJACENT 1
+#define NUM_SLOTS (1 + 2*KCSAN_CHECK_ADJACENT)
+
+extern unsigned int kcsan_udelay_task;
+extern unsigned int kcsan_udelay_interrupt;
+
+/*
+ * Globally enable and disable KCSAN.
+ */
+extern bool kcsan_enabled;
+
+/*
+ * Save/restore IRQ flags state trace dirtied by KCSAN.
+ */
+void kcsan_save_irqtrace(struct task_struct *task);
+void kcsan_restore_irqtrace(struct task_struct *task);
+
+/*
+ * Statistics counters displayed via debugfs; should only be modified in
+ * slow-paths.
+ */
+enum kcsan_counter_id {
+	/*
+	 * Number of watchpoints currently in use.
+	 */
+	KCSAN_COUNTER_USED_WATCHPOINTS,
+
+	/*
+	 * Total number of watchpoints set up.
+	 */
+	KCSAN_COUNTER_SETUP_WATCHPOINTS,
+
+	/*
+	 * Total number of data races.
+	 */
+	KCSAN_COUNTER_DATA_RACES,
+
+	/*
+	 * Total number of ASSERT failures due to races. If the observed race is
+	 * due to two conflicting ASSERT type accesses, then both will be
+	 * counted.
+	 */
+	KCSAN_COUNTER_ASSERT_FAILURES,
+
+	/*
+	 * Number of times no watchpoints were available.
+	 */
+	KCSAN_COUNTER_NO_CAPACITY,
+
+	/*
+	 * A thread checking a watchpoint raced with another checking thread;
+	 * only one will be reported.
+	 */
+	KCSAN_COUNTER_REPORT_RACES,
+
+	/*
+	 * Observed data value change, but writer thread unknown.
+	 */
+	KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN,
+
+	/*
+	 * The access cannot be encoded to a valid watchpoint.
+	 */
+	KCSAN_COUNTER_UNENCODABLE_ACCESSES,
+
+	/*
+	 * Watchpoint encoding caused a watchpoint to fire on mismatching
+	 * accesses.
+	 */
+	KCSAN_COUNTER_ENCODING_FALSE_POSITIVES,
+
+	KCSAN_COUNTER_COUNT, /* number of counters */
+};
+extern atomic_long_t kcsan_counters[KCSAN_COUNTER_COUNT];
+
+/*
+ * Returns true if data races in the function symbol that maps to func_addr
+ * (offsets are ignored) should *not* be reported.
+ */
+extern bool kcsan_skip_report_debugfs(unsigned long func_addr);
+
+/*
+ * Value-change states.
+ */
+enum kcsan_value_change {
+	/*
+	 * Did not observe a value-change, however, it is valid to report the
+	 * race, depending on preferences.
+	 */
+	KCSAN_VALUE_CHANGE_MAYBE,
+
+	/*
+	 * Did not observe a value-change, and it is invalid to report the race.
+	 */
+	KCSAN_VALUE_CHANGE_FALSE,
+
+	/*
+	 * The value was observed to change, and the race should be reported.
+	 */
+	KCSAN_VALUE_CHANGE_TRUE,
+};
+
+/*
+ * The calling thread hit and consumed a watchpoint: set the access information
+ * to be consumed by the reporting thread. No report is printed yet.
+ */
+void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_type,
+			   unsigned long ip, int watchpoint_idx);
+
+/*
+ * The calling thread observed that the watchpoint it set up was hit and
+ * consumed: print the full report based on information set by the racing
+ * thread.
+ */
+void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access_type,
+			       unsigned long ip, enum kcsan_value_change value_change,
+			       int watchpoint_idx, u64 old, u64 new, u64 mask);
+
+/*
+ * No other thread was observed to race with the access, but the data value
+ * before and after the stall differs. Reports a race of "unknown origin".
+ */
+void kcsan_report_unknown_origin(const volatile void *ptr, size_t size, int access_type,
+				 unsigned long ip, u64 old, u64 new, u64 mask);
+
+#endif /* _KERNEL_KCSAN_KCSAN_H */
diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c
new file mode 100644
index 000000000..a60c56172
--- /dev/null
+++ b/kernel/kcsan/kcsan_test.c
@@ -0,0 +1,1618 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KCSAN test with various race scenarious to test runtime behaviour. Since the
+ * interface with which KCSAN's reports are obtained is via the console, this is
+ * the output we should verify. For each test case checks the presence (or
+ * absence) of generated reports. Relies on 'console' tracepoint to capture
+ * reports as they appear in the kernel log.
+ *
+ * Makes use of KUnit for test organization, and the Torture framework for test
+ * thread control.
+ *
+ * Copyright (C) 2020, Google LLC.
+ * Author: Marco Elver <elver@google.com>
+ */
+
+#define pr_fmt(fmt) "kcsan_test: " fmt
+
+#include <kunit/test.h>
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/jiffies.h>
+#include <linux/kcsan-checks.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/seqlock.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/timer.h>
+#include <linux/torture.h>
+#include <linux/tracepoint.h>
+#include <linux/types.h>
+#include <trace/events/printk.h>
+
+#define KCSAN_TEST_REQUIRES(test, cond) do {			\
+	if (!(cond))						\
+		kunit_skip((test), "Test requires: " #cond);	\
+} while (0)
+
+#ifdef CONFIG_CC_HAS_TSAN_COMPOUND_READ_BEFORE_WRITE
+#define __KCSAN_ACCESS_RW(alt) (KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE)
+#else
+#define __KCSAN_ACCESS_RW(alt) (alt)
+#endif
+
+/* Points to current test-case memory access "kernels". */
+static void (*access_kernels[2])(void);
+
+static struct task_struct **threads; /* Lists of threads. */
+static unsigned long end_time;       /* End time of test. */
+
+/* Report as observed from console. */
+static struct {
+	spinlock_t lock;
+	int nlines;
+	char lines[3][512];
+} observed = {
+	.lock = __SPIN_LOCK_UNLOCKED(observed.lock),
+};
+
+/* Setup test checking loop. */
+static __no_kcsan inline void
+begin_test_checks(void (*func1)(void), void (*func2)(void))
+{
+	kcsan_disable_current();
+
+	/*
+	 * Require at least as long as KCSAN_REPORT_ONCE_IN_MS, to ensure at
+	 * least one race is reported.
+	 */
+	end_time = jiffies + msecs_to_jiffies(CONFIG_KCSAN_REPORT_ONCE_IN_MS + 500);
+
+	/* Signal start; release potential initialization of shared data. */
+	smp_store_release(&access_kernels[0], func1);
+	smp_store_release(&access_kernels[1], func2);
+}
+
+/* End test checking loop. */
+static __no_kcsan inline bool
+end_test_checks(bool stop)
+{
+	if (!stop && time_before(jiffies, end_time)) {
+		/* Continue checking */
+		might_sleep();
+		return false;
+	}
+
+	kcsan_enable_current();
+	return true;
+}
+
+/*
+ * Probe for console output: checks if a race was reported, and obtains observed
+ * lines of interest.
+ */
+__no_kcsan
+static void probe_console(void *ignore, const char *buf, size_t len)
+{
+	unsigned long flags;
+	int nlines;
+
+	/*
+	 * Note that KCSAN reports under a global lock, so we do not risk the
+	 * possibility of having multiple reports interleaved. If that were the
+	 * case, we'd expect tests to fail.
+	 */
+
+	spin_lock_irqsave(&observed.lock, flags);
+	nlines = observed.nlines;
+
+	if (strnstr(buf, "BUG: KCSAN: ", len) && strnstr(buf, "test_", len)) {
+		/*
+		 * KCSAN report and related to the test.
+		 *
+		 * The provided @buf is not NUL-terminated; copy no more than
+		 * @len bytes and let strscpy() add the missing NUL-terminator.
+		 */
+		strscpy(observed.lines[0], buf, min(len + 1, sizeof(observed.lines[0])));
+		nlines = 1;
+	} else if ((nlines == 1 || nlines == 2) && strnstr(buf, "bytes by", len)) {
+		strscpy(observed.lines[nlines++], buf, min(len + 1, sizeof(observed.lines[0])));
+
+		if (strnstr(buf, "race at unknown origin", len)) {
+			if (WARN_ON(nlines != 2))
+				goto out;
+
+			/* No second line of interest. */
+			strcpy(observed.lines[nlines++], "<none>");
+		}
+	}
+
+out:
+	WRITE_ONCE(observed.nlines, nlines); /* Publish new nlines. */
+	spin_unlock_irqrestore(&observed.lock, flags);
+}
+
+/* Check if a report related to the test exists. */
+__no_kcsan
+static bool report_available(void)
+{
+	return READ_ONCE(observed.nlines) == ARRAY_SIZE(observed.lines);
+}
+
+/* Report information we expect in a report. */
+struct expect_report {
+	/* Access information of both accesses. */
+	struct {
+		void *fn;    /* Function pointer to expected function of top frame. */
+		void *addr;  /* Address of access; unchecked if NULL. */
+		size_t size; /* Size of access; unchecked if @addr is NULL. */
+		int type;    /* Access type, see KCSAN_ACCESS definitions. */
+	} access[2];
+};
+
+/* Check observed report matches information in @r. */
+__no_kcsan
+static bool __report_matches(const struct expect_report *r)
+{
+	const bool is_assert = (r->access[0].type | r->access[1].type) & KCSAN_ACCESS_ASSERT;
+	bool ret = false;
+	unsigned long flags;
+	typeof(*observed.lines) *expect;
+	const char *end;
+	char *cur;
+	int i;
+
+	/* Doubled-checked locking. */
+	if (!report_available())
+		return false;
+
+	expect = kmalloc(sizeof(observed.lines), GFP_KERNEL);
+	if (WARN_ON(!expect))
+		return false;
+
+	/* Generate expected report contents. */
+
+	/* Title */
+	cur = expect[0];
+	end = &expect[0][sizeof(expect[0]) - 1];
+	cur += scnprintf(cur, end - cur, "BUG: KCSAN: %s in ",
+			 is_assert ? "assert: race" : "data-race");
+	if (r->access[1].fn) {
+		char tmp[2][64];
+		int cmp;
+
+		/* Expect lexographically sorted function names in title. */
+		scnprintf(tmp[0], sizeof(tmp[0]), "%pS", r->access[0].fn);
+		scnprintf(tmp[1], sizeof(tmp[1]), "%pS", r->access[1].fn);
+		cmp = strcmp(tmp[0], tmp[1]);
+		cur += scnprintf(cur, end - cur, "%ps / %ps",
+				 cmp < 0 ? r->access[0].fn : r->access[1].fn,
+				 cmp < 0 ? r->access[1].fn : r->access[0].fn);
+	} else {
+		scnprintf(cur, end - cur, "%pS", r->access[0].fn);
+		/* The exact offset won't match, remove it. */
+		cur = strchr(expect[0], '+');
+		if (cur)
+			*cur = '\0';
+	}
+
+	/* Access 1 */
+	cur = expect[1];
+	end = &expect[1][sizeof(expect[1]) - 1];
+	if (!r->access[1].fn)
+		cur += scnprintf(cur, end - cur, "race at unknown origin, with ");
+
+	/* Access 1 & 2 */
+	for (i = 0; i < 2; ++i) {
+		const int ty = r->access[i].type;
+		const char *const access_type =
+			(ty & KCSAN_ACCESS_ASSERT) ?
+				      ((ty & KCSAN_ACCESS_WRITE) ?
+					       "assert no accesses" :
+					       "assert no writes") :
+				      ((ty & KCSAN_ACCESS_WRITE) ?
+					       ((ty & KCSAN_ACCESS_COMPOUND) ?
+							"read-write" :
+							"write") :
+					       "read");
+		const bool is_atomic = (ty & KCSAN_ACCESS_ATOMIC);
+		const bool is_scoped = (ty & KCSAN_ACCESS_SCOPED);
+		const char *const access_type_aux =
+				(is_atomic && is_scoped)	? " (marked, reordered)"
+				: (is_atomic			? " (marked)"
+				   : (is_scoped			? " (reordered)" : ""));
+
+		if (i == 1) {
+			/* Access 2 */
+			cur = expect[2];
+			end = &expect[2][sizeof(expect[2]) - 1];
+
+			if (!r->access[1].fn) {
+				/* Dummy string if no second access is available. */
+				strcpy(cur, "<none>");
+				break;
+			}
+		}
+
+		cur += scnprintf(cur, end - cur, "%s%s to ", access_type,
+				 access_type_aux);
+
+		if (r->access[i].addr) /* Address is optional. */
+			cur += scnprintf(cur, end - cur, "0x%px of %zu bytes",
+					 r->access[i].addr, r->access[i].size);
+	}
+
+	spin_lock_irqsave(&observed.lock, flags);
+	if (!report_available())
+		goto out; /* A new report is being captured. */
+
+	/* Finally match expected output to what we actually observed. */
+	ret = strstr(observed.lines[0], expect[0]) &&
+	      /* Access info may appear in any order. */
+	      ((strstr(observed.lines[1], expect[1]) &&
+		strstr(observed.lines[2], expect[2])) ||
+	       (strstr(observed.lines[1], expect[2]) &&
+		strstr(observed.lines[2], expect[1])));
+out:
+	spin_unlock_irqrestore(&observed.lock, flags);
+	kfree(expect);
+	return ret;
+}
+
+static __always_inline const struct expect_report *
+__report_set_scoped(struct expect_report *r, int accesses)
+{
+	BUILD_BUG_ON(accesses > 3);
+
+	if (accesses & 1)
+		r->access[0].type |= KCSAN_ACCESS_SCOPED;
+	else
+		r->access[0].type &= ~KCSAN_ACCESS_SCOPED;
+
+	if (accesses & 2)
+		r->access[1].type |= KCSAN_ACCESS_SCOPED;
+	else
+		r->access[1].type &= ~KCSAN_ACCESS_SCOPED;
+
+	return r;
+}
+
+__no_kcsan
+static bool report_matches_any_reordered(struct expect_report *r)
+{
+	return __report_matches(__report_set_scoped(r, 0)) ||
+	       __report_matches(__report_set_scoped(r, 1)) ||
+	       __report_matches(__report_set_scoped(r, 2)) ||
+	       __report_matches(__report_set_scoped(r, 3));
+}
+
+#ifdef CONFIG_KCSAN_WEAK_MEMORY
+/* Due to reordering accesses, any access may appear as "(reordered)". */
+#define report_matches report_matches_any_reordered
+#else
+#define report_matches __report_matches
+#endif
+
+/* ===== Test kernels ===== */
+
+static long test_sink;
+static long test_var;
+/* @test_array should be large enough to fall into multiple watchpoint slots. */
+static long test_array[3 * PAGE_SIZE / sizeof(long)];
+static struct {
+	long val[8];
+} test_struct;
+static DEFINE_SEQLOCK(test_seqlock);
+static DEFINE_SPINLOCK(test_spinlock);
+static DEFINE_MUTEX(test_mutex);
+
+/*
+ * Helper to avoid compiler optimizing out reads, and to generate source values
+ * for writes.
+ */
+__no_kcsan
+static noinline void sink_value(long v) { WRITE_ONCE(test_sink, v); }
+
+/*
+ * Generates a delay and some accesses that enter the runtime but do not produce
+ * data races.
+ */
+static noinline void test_delay(int iter)
+{
+	while (iter--)
+		sink_value(READ_ONCE(test_sink));
+}
+
+static noinline void test_kernel_read(void) { sink_value(test_var); }
+
+static noinline void test_kernel_write(void)
+{
+	test_var = READ_ONCE_NOCHECK(test_sink) + 1;
+}
+
+static noinline void test_kernel_write_nochange(void) { test_var = 42; }
+
+/* Suffixed by value-change exception filter. */
+static noinline void test_kernel_write_nochange_rcu(void) { test_var = 42; }
+
+static noinline void test_kernel_read_atomic(void)
+{
+	sink_value(READ_ONCE(test_var));
+}
+
+static noinline void test_kernel_write_atomic(void)
+{
+	WRITE_ONCE(test_var, READ_ONCE_NOCHECK(test_sink) + 1);
+}
+
+static noinline void test_kernel_atomic_rmw(void)
+{
+	/* Use builtin, so we can set up the "bad" atomic/non-atomic scenario. */
+	__atomic_fetch_add(&test_var, 1, __ATOMIC_RELAXED);
+}
+
+__no_kcsan
+static noinline void test_kernel_write_uninstrumented(void) { test_var++; }
+
+static noinline void test_kernel_data_race(void) { data_race(test_var++); }
+
+static noinline void test_kernel_assert_writer(void)
+{
+	ASSERT_EXCLUSIVE_WRITER(test_var);
+}
+
+static noinline void test_kernel_assert_access(void)
+{
+	ASSERT_EXCLUSIVE_ACCESS(test_var);
+}
+
+#define TEST_CHANGE_BITS 0xff00ff00
+
+static noinline void test_kernel_change_bits(void)
+{
+	if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) {
+		/*
+		 * Avoid race of unknown origin for this test, just pretend they
+		 * are atomic.
+		 */
+		kcsan_nestable_atomic_begin();
+		test_var ^= TEST_CHANGE_BITS;
+		kcsan_nestable_atomic_end();
+	} else
+		WRITE_ONCE(test_var, READ_ONCE(test_var) ^ TEST_CHANGE_BITS);
+}
+
+static noinline void test_kernel_assert_bits_change(void)
+{
+	ASSERT_EXCLUSIVE_BITS(test_var, TEST_CHANGE_BITS);
+}
+
+static noinline void test_kernel_assert_bits_nochange(void)
+{
+	ASSERT_EXCLUSIVE_BITS(test_var, ~TEST_CHANGE_BITS);
+}
+
+/*
+ * Scoped assertions do trigger anywhere in scope. However, the report should
+ * still only point at the start of the scope.
+ */
+static noinline void test_enter_scope(void)
+{
+	int x = 0;
+
+	/* Unrelated accesses to scoped assert. */
+	READ_ONCE(test_sink);
+	kcsan_check_read(&x, sizeof(x));
+}
+
+static noinline void test_kernel_assert_writer_scoped(void)
+{
+	ASSERT_EXCLUSIVE_WRITER_SCOPED(test_var);
+	test_enter_scope();
+}
+
+static noinline void test_kernel_assert_access_scoped(void)
+{
+	ASSERT_EXCLUSIVE_ACCESS_SCOPED(test_var);
+	test_enter_scope();
+}
+
+static noinline void test_kernel_rmw_array(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(test_array); ++i)
+		test_array[i]++;
+}
+
+static noinline void test_kernel_write_struct(void)
+{
+	kcsan_check_write(&test_struct, sizeof(test_struct));
+	kcsan_disable_current();
+	test_struct.val[3]++; /* induce value change */
+	kcsan_enable_current();
+}
+
+static noinline void test_kernel_write_struct_part(void)
+{
+	test_struct.val[3] = 42;
+}
+
+static noinline void test_kernel_read_struct_zero_size(void)
+{
+	kcsan_check_read(&test_struct.val[3], 0);
+}
+
+static noinline void test_kernel_jiffies_reader(void)
+{
+	sink_value((long)jiffies);
+}
+
+static noinline void test_kernel_seqlock_reader(void)
+{
+	unsigned int seq;
+
+	do {
+		seq = read_seqbegin(&test_seqlock);
+		sink_value(test_var);
+	} while (read_seqretry(&test_seqlock, seq));
+}
+
+static noinline void test_kernel_seqlock_writer(void)
+{
+	unsigned long flags;
+
+	write_seqlock_irqsave(&test_seqlock, flags);
+	test_var++;
+	write_sequnlock_irqrestore(&test_seqlock, flags);
+}
+
+static noinline void test_kernel_atomic_builtins(void)
+{
+	/*
+	 * Generate concurrent accesses, expecting no reports, ensuring KCSAN
+	 * treats builtin atomics as actually atomic.
+	 */
+	__atomic_load_n(&test_var, __ATOMIC_RELAXED);
+}
+
+static noinline void test_kernel_xor_1bit(void)
+{
+	/* Do not report data races between the read-writes. */
+	kcsan_nestable_atomic_begin();
+	test_var ^= 0x10000;
+	kcsan_nestable_atomic_end();
+}
+
+#define TEST_KERNEL_LOCKED(name, acquire, release)		\
+	static noinline void test_kernel_##name(void)		\
+	{							\
+		long *flag = &test_struct.val[0];		\
+		long v = 0;					\
+		if (!(acquire))					\
+			return;					\
+		while (v++ < 100) {				\
+			test_var++;				\
+			barrier();				\
+		}						\
+		release;					\
+		test_delay(10);					\
+	}
+
+TEST_KERNEL_LOCKED(with_memorder,
+		   cmpxchg_acquire(flag, 0, 1) == 0,
+		   smp_store_release(flag, 0));
+TEST_KERNEL_LOCKED(wrong_memorder,
+		   cmpxchg_relaxed(flag, 0, 1) == 0,
+		   WRITE_ONCE(*flag, 0));
+TEST_KERNEL_LOCKED(atomic_builtin_with_memorder,
+		   __atomic_compare_exchange_n(flag, &v, 1, 0, __ATOMIC_ACQUIRE, __ATOMIC_RELAXED),
+		   __atomic_store_n(flag, 0, __ATOMIC_RELEASE));
+TEST_KERNEL_LOCKED(atomic_builtin_wrong_memorder,
+		   __atomic_compare_exchange_n(flag, &v, 1, 0, __ATOMIC_RELAXED, __ATOMIC_RELAXED),
+		   __atomic_store_n(flag, 0, __ATOMIC_RELAXED));
+
+/* ===== Test cases ===== */
+
+/*
+ * Tests that various barriers have the expected effect on internal state. Not
+ * exhaustive on atomic_t operations. Unlike the selftest, also checks for
+ * too-strict barrier instrumentation; these can be tolerated, because it does
+ * not cause false positives, but at least we should be aware of such cases.
+ */
+static void test_barrier_nothreads(struct kunit *test)
+{
+#ifdef CONFIG_KCSAN_WEAK_MEMORY
+	struct kcsan_scoped_access *reorder_access = &current->kcsan_ctx.reorder_access;
+#else
+	struct kcsan_scoped_access *reorder_access = NULL;
+#endif
+	arch_spinlock_t arch_spinlock = __ARCH_SPIN_LOCK_UNLOCKED;
+	atomic_t dummy;
+
+	KCSAN_TEST_REQUIRES(test, reorder_access != NULL);
+	KCSAN_TEST_REQUIRES(test, IS_ENABLED(CONFIG_SMP));
+
+#define __KCSAN_EXPECT_BARRIER(access_type, barrier, order_before, name)			\
+	do {											\
+		reorder_access->type = (access_type) | KCSAN_ACCESS_SCOPED;			\
+		reorder_access->size = sizeof(test_var);					\
+		barrier;									\
+		KUNIT_EXPECT_EQ_MSG(test, reorder_access->size,					\
+				    order_before ? 0 : sizeof(test_var),			\
+				    "improperly instrumented type=(" #access_type "): " name);	\
+	} while (0)
+#define KCSAN_EXPECT_READ_BARRIER(b, o)  __KCSAN_EXPECT_BARRIER(0, b, o, #b)
+#define KCSAN_EXPECT_WRITE_BARRIER(b, o) __KCSAN_EXPECT_BARRIER(KCSAN_ACCESS_WRITE, b, o, #b)
+#define KCSAN_EXPECT_RW_BARRIER(b, o)    __KCSAN_EXPECT_BARRIER(KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE, b, o, #b)
+
+	/*
+	 * Lockdep initialization can strengthen certain locking operations due
+	 * to calling into instrumented files; "warm up" our locks.
+	 */
+	spin_lock(&test_spinlock);
+	spin_unlock(&test_spinlock);
+	mutex_lock(&test_mutex);
+	mutex_unlock(&test_mutex);
+
+	/* Force creating a valid entry in reorder_access first. */
+	test_var = 0;
+	while (test_var++ < 1000000 && reorder_access->size != sizeof(test_var))
+		__kcsan_check_read(&test_var, sizeof(test_var));
+	KUNIT_ASSERT_EQ(test, reorder_access->size, sizeof(test_var));
+
+	kcsan_nestable_atomic_begin(); /* No watchpoints in called functions. */
+
+	KCSAN_EXPECT_READ_BARRIER(mb(), true);
+	KCSAN_EXPECT_READ_BARRIER(wmb(), false);
+	KCSAN_EXPECT_READ_BARRIER(rmb(), true);
+	KCSAN_EXPECT_READ_BARRIER(smp_mb(), true);
+	KCSAN_EXPECT_READ_BARRIER(smp_wmb(), false);
+	KCSAN_EXPECT_READ_BARRIER(smp_rmb(), true);
+	KCSAN_EXPECT_READ_BARRIER(dma_wmb(), false);
+	KCSAN_EXPECT_READ_BARRIER(dma_rmb(), true);
+	KCSAN_EXPECT_READ_BARRIER(smp_mb__before_atomic(), true);
+	KCSAN_EXPECT_READ_BARRIER(smp_mb__after_atomic(), true);
+	KCSAN_EXPECT_READ_BARRIER(smp_mb__after_spinlock(), true);
+	KCSAN_EXPECT_READ_BARRIER(smp_store_mb(test_var, 0), true);
+	KCSAN_EXPECT_READ_BARRIER(smp_load_acquire(&test_var), false);
+	KCSAN_EXPECT_READ_BARRIER(smp_store_release(&test_var, 0), true);
+	KCSAN_EXPECT_READ_BARRIER(xchg(&test_var, 0), true);
+	KCSAN_EXPECT_READ_BARRIER(xchg_release(&test_var, 0), true);
+	KCSAN_EXPECT_READ_BARRIER(xchg_relaxed(&test_var, 0), false);
+	KCSAN_EXPECT_READ_BARRIER(cmpxchg(&test_var, 0,  0), true);
+	KCSAN_EXPECT_READ_BARRIER(cmpxchg_release(&test_var, 0,  0), true);
+	KCSAN_EXPECT_READ_BARRIER(cmpxchg_relaxed(&test_var, 0,  0), false);
+	KCSAN_EXPECT_READ_BARRIER(atomic_read(&dummy), false);
+	KCSAN_EXPECT_READ_BARRIER(atomic_read_acquire(&dummy), false);
+	KCSAN_EXPECT_READ_BARRIER(atomic_set(&dummy, 0), false);
+	KCSAN_EXPECT_READ_BARRIER(atomic_set_release(&dummy, 0), true);
+	KCSAN_EXPECT_READ_BARRIER(atomic_add(1, &dummy), false);
+	KCSAN_EXPECT_READ_BARRIER(atomic_add_return(1, &dummy), true);
+	KCSAN_EXPECT_READ_BARRIER(atomic_add_return_acquire(1, &dummy), false);
+	KCSAN_EXPECT_READ_BARRIER(atomic_add_return_release(1, &dummy), true);
+	KCSAN_EXPECT_READ_BARRIER(atomic_add_return_relaxed(1, &dummy), false);
+	KCSAN_EXPECT_READ_BARRIER(atomic_fetch_add(1, &dummy), true);
+	KCSAN_EXPECT_READ_BARRIER(atomic_fetch_add_acquire(1, &dummy), false);
+	KCSAN_EXPECT_READ_BARRIER(atomic_fetch_add_release(1, &dummy), true);
+	KCSAN_EXPECT_READ_BARRIER(atomic_fetch_add_relaxed(1, &dummy), false);
+	KCSAN_EXPECT_READ_BARRIER(test_and_set_bit(0, &test_var), true);
+	KCSAN_EXPECT_READ_BARRIER(test_and_clear_bit(0, &test_var), true);
+	KCSAN_EXPECT_READ_BARRIER(test_and_change_bit(0, &test_var), true);
+	KCSAN_EXPECT_READ_BARRIER(clear_bit_unlock(0, &test_var), true);
+	KCSAN_EXPECT_READ_BARRIER(__clear_bit_unlock(0, &test_var), true);
+	KCSAN_EXPECT_READ_BARRIER(arch_spin_lock(&arch_spinlock), false);
+	KCSAN_EXPECT_READ_BARRIER(arch_spin_unlock(&arch_spinlock), true);
+	KCSAN_EXPECT_READ_BARRIER(spin_lock(&test_spinlock), false);
+	KCSAN_EXPECT_READ_BARRIER(spin_unlock(&test_spinlock), true);
+	KCSAN_EXPECT_READ_BARRIER(mutex_lock(&test_mutex), false);
+	KCSAN_EXPECT_READ_BARRIER(mutex_unlock(&test_mutex), true);
+
+	KCSAN_EXPECT_WRITE_BARRIER(mb(), true);
+	KCSAN_EXPECT_WRITE_BARRIER(wmb(), true);
+	KCSAN_EXPECT_WRITE_BARRIER(rmb(), false);
+	KCSAN_EXPECT_WRITE_BARRIER(smp_mb(), true);
+	KCSAN_EXPECT_WRITE_BARRIER(smp_wmb(), true);
+	KCSAN_EXPECT_WRITE_BARRIER(smp_rmb(), false);
+	KCSAN_EXPECT_WRITE_BARRIER(dma_wmb(), true);
+	KCSAN_EXPECT_WRITE_BARRIER(dma_rmb(), false);
+	KCSAN_EXPECT_WRITE_BARRIER(smp_mb__before_atomic(), true);
+	KCSAN_EXPECT_WRITE_BARRIER(smp_mb__after_atomic(), true);
+	KCSAN_EXPECT_WRITE_BARRIER(smp_mb__after_spinlock(), true);
+	KCSAN_EXPECT_WRITE_BARRIER(smp_store_mb(test_var, 0), true);
+	KCSAN_EXPECT_WRITE_BARRIER(smp_load_acquire(&test_var), false);
+	KCSAN_EXPECT_WRITE_BARRIER(smp_store_release(&test_var, 0), true);
+	KCSAN_EXPECT_WRITE_BARRIER(xchg(&test_var, 0), true);
+	KCSAN_EXPECT_WRITE_BARRIER(xchg_release(&test_var, 0), true);
+	KCSAN_EXPECT_WRITE_BARRIER(xchg_relaxed(&test_var, 0), false);
+	KCSAN_EXPECT_WRITE_BARRIER(cmpxchg(&test_var, 0,  0), true);
+	KCSAN_EXPECT_WRITE_BARRIER(cmpxchg_release(&test_var, 0,  0), true);
+	KCSAN_EXPECT_WRITE_BARRIER(cmpxchg_relaxed(&test_var, 0,  0), false);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_read(&dummy), false);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_read_acquire(&dummy), false);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_set(&dummy, 0), false);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_set_release(&dummy, 0), true);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_add(1, &dummy), false);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_add_return(1, &dummy), true);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_add_return_acquire(1, &dummy), false);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_add_return_release(1, &dummy), true);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_add_return_relaxed(1, &dummy), false);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_fetch_add(1, &dummy), true);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_fetch_add_acquire(1, &dummy), false);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_fetch_add_release(1, &dummy), true);
+	KCSAN_EXPECT_WRITE_BARRIER(atomic_fetch_add_relaxed(1, &dummy), false);
+	KCSAN_EXPECT_WRITE_BARRIER(test_and_set_bit(0, &test_var), true);
+	KCSAN_EXPECT_WRITE_BARRIER(test_and_clear_bit(0, &test_var), true);
+	KCSAN_EXPECT_WRITE_BARRIER(test_and_change_bit(0, &test_var), true);
+	KCSAN_EXPECT_WRITE_BARRIER(clear_bit_unlock(0, &test_var), true);
+	KCSAN_EXPECT_WRITE_BARRIER(__clear_bit_unlock(0, &test_var), true);
+	KCSAN_EXPECT_WRITE_BARRIER(arch_spin_lock(&arch_spinlock), false);
+	KCSAN_EXPECT_WRITE_BARRIER(arch_spin_unlock(&arch_spinlock), true);
+	KCSAN_EXPECT_WRITE_BARRIER(spin_lock(&test_spinlock), false);
+	KCSAN_EXPECT_WRITE_BARRIER(spin_unlock(&test_spinlock), true);
+	KCSAN_EXPECT_WRITE_BARRIER(mutex_lock(&test_mutex), false);
+	KCSAN_EXPECT_WRITE_BARRIER(mutex_unlock(&test_mutex), true);
+
+	KCSAN_EXPECT_RW_BARRIER(mb(), true);
+	KCSAN_EXPECT_RW_BARRIER(wmb(), true);
+	KCSAN_EXPECT_RW_BARRIER(rmb(), true);
+	KCSAN_EXPECT_RW_BARRIER(smp_mb(), true);
+	KCSAN_EXPECT_RW_BARRIER(smp_wmb(), true);
+	KCSAN_EXPECT_RW_BARRIER(smp_rmb(), true);
+	KCSAN_EXPECT_RW_BARRIER(dma_wmb(), true);
+	KCSAN_EXPECT_RW_BARRIER(dma_rmb(), true);
+	KCSAN_EXPECT_RW_BARRIER(smp_mb__before_atomic(), true);
+	KCSAN_EXPECT_RW_BARRIER(smp_mb__after_atomic(), true);
+	KCSAN_EXPECT_RW_BARRIER(smp_mb__after_spinlock(), true);
+	KCSAN_EXPECT_RW_BARRIER(smp_store_mb(test_var, 0), true);
+	KCSAN_EXPECT_RW_BARRIER(smp_load_acquire(&test_var), false);
+	KCSAN_EXPECT_RW_BARRIER(smp_store_release(&test_var, 0), true);
+	KCSAN_EXPECT_RW_BARRIER(xchg(&test_var, 0), true);
+	KCSAN_EXPECT_RW_BARRIER(xchg_release(&test_var, 0), true);
+	KCSAN_EXPECT_RW_BARRIER(xchg_relaxed(&test_var, 0), false);
+	KCSAN_EXPECT_RW_BARRIER(cmpxchg(&test_var, 0,  0), true);
+	KCSAN_EXPECT_RW_BARRIER(cmpxchg_release(&test_var, 0,  0), true);
+	KCSAN_EXPECT_RW_BARRIER(cmpxchg_relaxed(&test_var, 0,  0), false);
+	KCSAN_EXPECT_RW_BARRIER(atomic_read(&dummy), false);
+	KCSAN_EXPECT_RW_BARRIER(atomic_read_acquire(&dummy), false);
+	KCSAN_EXPECT_RW_BARRIER(atomic_set(&dummy, 0), false);
+	KCSAN_EXPECT_RW_BARRIER(atomic_set_release(&dummy, 0), true);
+	KCSAN_EXPECT_RW_BARRIER(atomic_add(1, &dummy), false);
+	KCSAN_EXPECT_RW_BARRIER(atomic_add_return(1, &dummy), true);
+	KCSAN_EXPECT_RW_BARRIER(atomic_add_return_acquire(1, &dummy), false);
+	KCSAN_EXPECT_RW_BARRIER(atomic_add_return_release(1, &dummy), true);
+	KCSAN_EXPECT_RW_BARRIER(atomic_add_return_relaxed(1, &dummy), false);
+	KCSAN_EXPECT_RW_BARRIER(atomic_fetch_add(1, &dummy), true);
+	KCSAN_EXPECT_RW_BARRIER(atomic_fetch_add_acquire(1, &dummy), false);
+	KCSAN_EXPECT_RW_BARRIER(atomic_fetch_add_release(1, &dummy), true);
+	KCSAN_EXPECT_RW_BARRIER(atomic_fetch_add_relaxed(1, &dummy), false);
+	KCSAN_EXPECT_RW_BARRIER(test_and_set_bit(0, &test_var), true);
+	KCSAN_EXPECT_RW_BARRIER(test_and_clear_bit(0, &test_var), true);
+	KCSAN_EXPECT_RW_BARRIER(test_and_change_bit(0, &test_var), true);
+	KCSAN_EXPECT_RW_BARRIER(clear_bit_unlock(0, &test_var), true);
+	KCSAN_EXPECT_RW_BARRIER(__clear_bit_unlock(0, &test_var), true);
+	KCSAN_EXPECT_RW_BARRIER(arch_spin_lock(&arch_spinlock), false);
+	KCSAN_EXPECT_RW_BARRIER(arch_spin_unlock(&arch_spinlock), true);
+	KCSAN_EXPECT_RW_BARRIER(spin_lock(&test_spinlock), false);
+	KCSAN_EXPECT_RW_BARRIER(spin_unlock(&test_spinlock), true);
+	KCSAN_EXPECT_RW_BARRIER(mutex_lock(&test_mutex), false);
+	KCSAN_EXPECT_RW_BARRIER(mutex_unlock(&test_mutex), true);
+
+#ifdef clear_bit_unlock_is_negative_byte
+	KCSAN_EXPECT_READ_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var), true);
+	KCSAN_EXPECT_WRITE_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var), true);
+	KCSAN_EXPECT_RW_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var), true);
+#endif
+	kcsan_nestable_atomic_end();
+}
+
+/* Simple test with normal data race. */
+__no_kcsan
+static void test_basic(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_write, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
+			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
+		},
+	};
+	struct expect_report never = {
+		.access = {
+			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
+			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
+		},
+	};
+	bool match_expect = false;
+	bool match_never = false;
+
+	begin_test_checks(test_kernel_write, test_kernel_read);
+	do {
+		match_expect |= report_matches(&expect);
+		match_never = report_matches(&never);
+	} while (!end_test_checks(match_never));
+	KUNIT_EXPECT_TRUE(test, match_expect);
+	KUNIT_EXPECT_FALSE(test, match_never);
+}
+
+/*
+ * Stress KCSAN with lots of concurrent races on different addresses until
+ * timeout.
+ */
+__no_kcsan
+static void test_concurrent_races(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			/* NULL will match any address. */
+			{ test_kernel_rmw_array, NULL, 0, __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) },
+			{ test_kernel_rmw_array, NULL, 0, __KCSAN_ACCESS_RW(0) },
+		},
+	};
+	struct expect_report never = {
+		.access = {
+			{ test_kernel_rmw_array, NULL, 0, 0 },
+			{ test_kernel_rmw_array, NULL, 0, 0 },
+		},
+	};
+	bool match_expect = false;
+	bool match_never = false;
+
+	begin_test_checks(test_kernel_rmw_array, test_kernel_rmw_array);
+	do {
+		match_expect |= report_matches(&expect);
+		match_never |= report_matches(&never);
+	} while (!end_test_checks(false));
+	KUNIT_EXPECT_TRUE(test, match_expect); /* Sanity check matches exist. */
+	KUNIT_EXPECT_FALSE(test, match_never);
+}
+
+/* Test the KCSAN_REPORT_VALUE_CHANGE_ONLY option. */
+__no_kcsan
+static void test_novalue_change(struct kunit *test)
+{
+	struct expect_report expect_rw = {
+		.access = {
+			{ test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
+			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
+		},
+	};
+	struct expect_report expect_ww = {
+		.access = {
+			{ test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
+			{ test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
+		},
+	};
+	bool match_expect = false;
+
+	test_kernel_write_nochange(); /* Reset value. */
+	begin_test_checks(test_kernel_write_nochange, test_kernel_read);
+	do {
+		match_expect = report_matches(&expect_rw) || report_matches(&expect_ww);
+	} while (!end_test_checks(match_expect));
+	if (IS_ENABLED(CONFIG_KCSAN_REPORT_VALUE_CHANGE_ONLY))
+		KUNIT_EXPECT_FALSE(test, match_expect);
+	else
+		KUNIT_EXPECT_TRUE(test, match_expect);
+}
+
+/*
+ * Test that the rules where the KCSAN_REPORT_VALUE_CHANGE_ONLY option should
+ * never apply work.
+ */
+__no_kcsan
+static void test_novalue_change_exception(struct kunit *test)
+{
+	struct expect_report expect_rw = {
+		.access = {
+			{ test_kernel_write_nochange_rcu, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
+			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
+		},
+	};
+	struct expect_report expect_ww = {
+		.access = {
+			{ test_kernel_write_nochange_rcu, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
+			{ test_kernel_write_nochange_rcu, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
+		},
+	};
+	bool match_expect = false;
+
+	test_kernel_write_nochange_rcu(); /* Reset value. */
+	begin_test_checks(test_kernel_write_nochange_rcu, test_kernel_read);
+	do {
+		match_expect = report_matches(&expect_rw) || report_matches(&expect_ww);
+	} while (!end_test_checks(match_expect));
+	KUNIT_EXPECT_TRUE(test, match_expect);
+}
+
+/* Test that data races of unknown origin are reported. */
+__no_kcsan
+static void test_unknown_origin(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
+			{ NULL },
+		},
+	};
+	bool match_expect = false;
+
+	begin_test_checks(test_kernel_write_uninstrumented, test_kernel_read);
+	do {
+		match_expect = report_matches(&expect);
+	} while (!end_test_checks(match_expect));
+	if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN))
+		KUNIT_EXPECT_TRUE(test, match_expect);
+	else
+		KUNIT_EXPECT_FALSE(test, match_expect);
+}
+
+/* Test KCSAN_ASSUME_PLAIN_WRITES_ATOMIC if it is selected. */
+__no_kcsan
+static void test_write_write_assume_atomic(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_write, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
+			{ test_kernel_write, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
+		},
+	};
+	bool match_expect = false;
+
+	begin_test_checks(test_kernel_write, test_kernel_write);
+	do {
+		sink_value(READ_ONCE(test_var)); /* induce value-change */
+		match_expect = report_matches(&expect);
+	} while (!end_test_checks(match_expect));
+	if (IS_ENABLED(CONFIG_KCSAN_ASSUME_PLAIN_WRITES_ATOMIC))
+		KUNIT_EXPECT_FALSE(test, match_expect);
+	else
+		KUNIT_EXPECT_TRUE(test, match_expect);
+}
+
+/*
+ * Test that data races with writes larger than word-size are always reported,
+ * even if KCSAN_ASSUME_PLAIN_WRITES_ATOMIC is selected.
+ */
+__no_kcsan
+static void test_write_write_struct(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
+			{ test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
+		},
+	};
+	bool match_expect = false;
+
+	begin_test_checks(test_kernel_write_struct, test_kernel_write_struct);
+	do {
+		match_expect = report_matches(&expect);
+	} while (!end_test_checks(match_expect));
+	KUNIT_EXPECT_TRUE(test, match_expect);
+}
+
+/*
+ * Test that data races where only one write is larger than word-size are always
+ * reported, even if KCSAN_ASSUME_PLAIN_WRITES_ATOMIC is selected.
+ */
+__no_kcsan
+static void test_write_write_struct_part(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
+			{ test_kernel_write_struct_part, &test_struct.val[3], sizeof(test_struct.val[3]), KCSAN_ACCESS_WRITE },
+		},
+	};
+	bool match_expect = false;
+
+	begin_test_checks(test_kernel_write_struct, test_kernel_write_struct_part);
+	do {
+		match_expect = report_matches(&expect);
+	} while (!end_test_checks(match_expect));
+	KUNIT_EXPECT_TRUE(test, match_expect);
+}
+
+/* Test that races with atomic accesses never result in reports. */
+__no_kcsan
+static void test_read_atomic_write_atomic(struct kunit *test)
+{
+	bool match_never = false;
+
+	begin_test_checks(test_kernel_read_atomic, test_kernel_write_atomic);
+	do {
+		match_never = report_available();
+	} while (!end_test_checks(match_never));
+	KUNIT_EXPECT_FALSE(test, match_never);
+}
+
+/* Test that a race with an atomic and plain access result in reports. */
+__no_kcsan
+static void test_read_plain_atomic_write(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
+			{ test_kernel_write_atomic, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC },
+		},
+	};
+	bool match_expect = false;
+
+	KCSAN_TEST_REQUIRES(test, !IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS));
+
+	begin_test_checks(test_kernel_read, test_kernel_write_atomic);
+	do {
+		match_expect = report_matches(&expect);
+	} while (!end_test_checks(match_expect));
+	KUNIT_EXPECT_TRUE(test, match_expect);
+}
+
+/* Test that atomic RMWs generate correct report. */
+__no_kcsan
+static void test_read_plain_atomic_rmw(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
+			{ test_kernel_atomic_rmw, &test_var, sizeof(test_var),
+				KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC },
+		},
+	};
+	bool match_expect = false;
+
+	KCSAN_TEST_REQUIRES(test, !IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS));
+
+	begin_test_checks(test_kernel_read, test_kernel_atomic_rmw);
+	do {
+		match_expect = report_matches(&expect);
+	} while (!end_test_checks(match_expect));
+	KUNIT_EXPECT_TRUE(test, match_expect);
+}
+
+/* Zero-sized accesses should never cause data race reports. */
+__no_kcsan
+static void test_zero_size_access(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
+			{ test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
+		},
+	};
+	struct expect_report never = {
+		.access = {
+			{ test_kernel_write_struct, &test_struct, sizeof(test_struct), KCSAN_ACCESS_WRITE },
+			{ test_kernel_read_struct_zero_size, &test_struct.val[3], 0, 0 },
+		},
+	};
+	bool match_expect = false;
+	bool match_never = false;
+
+	begin_test_checks(test_kernel_write_struct, test_kernel_read_struct_zero_size);
+	do {
+		match_expect |= report_matches(&expect);
+		match_never = report_matches(&never);
+	} while (!end_test_checks(match_never));
+	KUNIT_EXPECT_TRUE(test, match_expect); /* Sanity check. */
+	KUNIT_EXPECT_FALSE(test, match_never);
+}
+
+/* Test the data_race() macro. */
+__no_kcsan
+static void test_data_race(struct kunit *test)
+{
+	bool match_never = false;
+
+	begin_test_checks(test_kernel_data_race, test_kernel_data_race);
+	do {
+		match_never = report_available();
+	} while (!end_test_checks(match_never));
+	KUNIT_EXPECT_FALSE(test, match_never);
+}
+
+__no_kcsan
+static void test_assert_exclusive_writer(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
+			{ test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
+		},
+	};
+	bool match_expect = false;
+
+	begin_test_checks(test_kernel_assert_writer, test_kernel_write_nochange);
+	do {
+		match_expect = report_matches(&expect);
+	} while (!end_test_checks(match_expect));
+	KUNIT_EXPECT_TRUE(test, match_expect);
+}
+
+__no_kcsan
+static void test_assert_exclusive_access(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE },
+			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
+		},
+	};
+	bool match_expect = false;
+
+	begin_test_checks(test_kernel_assert_access, test_kernel_read);
+	do {
+		match_expect = report_matches(&expect);
+	} while (!end_test_checks(match_expect));
+	KUNIT_EXPECT_TRUE(test, match_expect);
+}
+
+__no_kcsan
+static void test_assert_exclusive_access_writer(struct kunit *test)
+{
+	struct expect_report expect_access_writer = {
+		.access = {
+			{ test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE },
+			{ test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
+		},
+	};
+	struct expect_report expect_access_access = {
+		.access = {
+			{ test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE },
+			{ test_kernel_assert_access, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE },
+		},
+	};
+	struct expect_report never = {
+		.access = {
+			{ test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
+			{ test_kernel_assert_writer, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
+		},
+	};
+	bool match_expect_access_writer = false;
+	bool match_expect_access_access = false;
+	bool match_never = false;
+
+	begin_test_checks(test_kernel_assert_access, test_kernel_assert_writer);
+	do {
+		match_expect_access_writer |= report_matches(&expect_access_writer);
+		match_expect_access_access |= report_matches(&expect_access_access);
+		match_never |= report_matches(&never);
+	} while (!end_test_checks(match_never));
+	KUNIT_EXPECT_TRUE(test, match_expect_access_writer);
+	KUNIT_EXPECT_TRUE(test, match_expect_access_access);
+	KUNIT_EXPECT_FALSE(test, match_never);
+}
+
+__no_kcsan
+static void test_assert_exclusive_bits_change(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_assert_bits_change, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT },
+			{ test_kernel_change_bits, &test_var, sizeof(test_var),
+				KCSAN_ACCESS_WRITE | (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS) ? 0 : KCSAN_ACCESS_ATOMIC) },
+		},
+	};
+	bool match_expect = false;
+
+	begin_test_checks(test_kernel_assert_bits_change, test_kernel_change_bits);
+	do {
+		match_expect = report_matches(&expect);
+	} while (!end_test_checks(match_expect));
+	KUNIT_EXPECT_TRUE(test, match_expect);
+}
+
+__no_kcsan
+static void test_assert_exclusive_bits_nochange(struct kunit *test)
+{
+	bool match_never = false;
+
+	begin_test_checks(test_kernel_assert_bits_nochange, test_kernel_change_bits);
+	do {
+		match_never = report_available();
+	} while (!end_test_checks(match_never));
+	KUNIT_EXPECT_FALSE(test, match_never);
+}
+
+__no_kcsan
+static void test_assert_exclusive_writer_scoped(struct kunit *test)
+{
+	struct expect_report expect_start = {
+		.access = {
+			{ test_kernel_assert_writer_scoped, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_SCOPED },
+			{ test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
+		},
+	};
+	struct expect_report expect_inscope = {
+		.access = {
+			{ test_enter_scope, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_SCOPED },
+			{ test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE },
+		},
+	};
+	bool match_expect_start = false;
+	bool match_expect_inscope = false;
+
+	begin_test_checks(test_kernel_assert_writer_scoped, test_kernel_write_nochange);
+	do {
+		match_expect_start |= report_matches(&expect_start);
+		match_expect_inscope |= report_matches(&expect_inscope);
+	} while (!end_test_checks(match_expect_inscope));
+	KUNIT_EXPECT_TRUE(test, match_expect_start);
+	KUNIT_EXPECT_FALSE(test, match_expect_inscope);
+}
+
+__no_kcsan
+static void test_assert_exclusive_access_scoped(struct kunit *test)
+{
+	struct expect_report expect_start1 = {
+		.access = {
+			{ test_kernel_assert_access_scoped, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_SCOPED },
+			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
+		},
+	};
+	struct expect_report expect_start2 = {
+		.access = { expect_start1.access[0], expect_start1.access[0] },
+	};
+	struct expect_report expect_inscope = {
+		.access = {
+			{ test_enter_scope, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_SCOPED },
+			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
+		},
+	};
+	bool match_expect_start = false;
+	bool match_expect_inscope = false;
+
+	begin_test_checks(test_kernel_assert_access_scoped, test_kernel_read);
+	end_time += msecs_to_jiffies(1000); /* This test requires a bit more time. */
+	do {
+		match_expect_start |= report_matches(&expect_start1) || report_matches(&expect_start2);
+		match_expect_inscope |= report_matches(&expect_inscope);
+	} while (!end_test_checks(match_expect_inscope));
+	KUNIT_EXPECT_TRUE(test, match_expect_start);
+	KUNIT_EXPECT_FALSE(test, match_expect_inscope);
+}
+
+/*
+ * jiffies is special (declared to be volatile) and its accesses are typically
+ * not marked; this test ensures that the compiler nor KCSAN gets confused about
+ * jiffies's declaration on different architectures.
+ */
+__no_kcsan
+static void test_jiffies_noreport(struct kunit *test)
+{
+	bool match_never = false;
+
+	begin_test_checks(test_kernel_jiffies_reader, test_kernel_jiffies_reader);
+	do {
+		match_never = report_available();
+	} while (!end_test_checks(match_never));
+	KUNIT_EXPECT_FALSE(test, match_never);
+}
+
+/* Test that racing accesses in seqlock critical sections are not reported. */
+__no_kcsan
+static void test_seqlock_noreport(struct kunit *test)
+{
+	bool match_never = false;
+
+	begin_test_checks(test_kernel_seqlock_reader, test_kernel_seqlock_writer);
+	do {
+		match_never = report_available();
+	} while (!end_test_checks(match_never));
+	KUNIT_EXPECT_FALSE(test, match_never);
+}
+
+/*
+ * Test atomic builtins work and required instrumentation functions exist. We
+ * also test that KCSAN understands they're atomic by racing with them via
+ * test_kernel_atomic_builtins(), and expect no reports.
+ *
+ * The atomic builtins _SHOULD NOT_ be used in normal kernel code!
+ */
+static void test_atomic_builtins(struct kunit *test)
+{
+	bool match_never = false;
+
+	begin_test_checks(test_kernel_atomic_builtins, test_kernel_atomic_builtins);
+	do {
+		long tmp;
+
+		kcsan_enable_current();
+
+		__atomic_store_n(&test_var, 42L, __ATOMIC_RELAXED);
+		KUNIT_EXPECT_EQ(test, 42L, __atomic_load_n(&test_var, __ATOMIC_RELAXED));
+
+		KUNIT_EXPECT_EQ(test, 42L, __atomic_exchange_n(&test_var, 20, __ATOMIC_RELAXED));
+		KUNIT_EXPECT_EQ(test, 20L, test_var);
+
+		tmp = 20L;
+		KUNIT_EXPECT_TRUE(test, __atomic_compare_exchange_n(&test_var, &tmp, 30L,
+								    0, __ATOMIC_RELAXED,
+								    __ATOMIC_RELAXED));
+		KUNIT_EXPECT_EQ(test, tmp, 20L);
+		KUNIT_EXPECT_EQ(test, test_var, 30L);
+		KUNIT_EXPECT_FALSE(test, __atomic_compare_exchange_n(&test_var, &tmp, 40L,
+								     1, __ATOMIC_RELAXED,
+								     __ATOMIC_RELAXED));
+		KUNIT_EXPECT_EQ(test, tmp, 30L);
+		KUNIT_EXPECT_EQ(test, test_var, 30L);
+
+		KUNIT_EXPECT_EQ(test, 30L, __atomic_fetch_add(&test_var, 1, __ATOMIC_RELAXED));
+		KUNIT_EXPECT_EQ(test, 31L, __atomic_fetch_sub(&test_var, 1, __ATOMIC_RELAXED));
+		KUNIT_EXPECT_EQ(test, 30L, __atomic_fetch_and(&test_var, 0xf, __ATOMIC_RELAXED));
+		KUNIT_EXPECT_EQ(test, 14L, __atomic_fetch_xor(&test_var, 0xf, __ATOMIC_RELAXED));
+		KUNIT_EXPECT_EQ(test, 1L, __atomic_fetch_or(&test_var, 0xf0, __ATOMIC_RELAXED));
+		KUNIT_EXPECT_EQ(test, 241L, __atomic_fetch_nand(&test_var, 0xf, __ATOMIC_RELAXED));
+		KUNIT_EXPECT_EQ(test, -2L, test_var);
+
+		__atomic_thread_fence(__ATOMIC_SEQ_CST);
+		__atomic_signal_fence(__ATOMIC_SEQ_CST);
+
+		kcsan_disable_current();
+
+		match_never = report_available();
+	} while (!end_test_checks(match_never));
+	KUNIT_EXPECT_FALSE(test, match_never);
+}
+
+__no_kcsan
+static void test_1bit_value_change(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_read, &test_var, sizeof(test_var), 0 },
+			{ test_kernel_xor_1bit, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) },
+		},
+	};
+	bool match = false;
+
+	begin_test_checks(test_kernel_read, test_kernel_xor_1bit);
+	do {
+		match = IS_ENABLED(CONFIG_KCSAN_PERMISSIVE)
+				? report_available()
+				: report_matches(&expect);
+	} while (!end_test_checks(match));
+	if (IS_ENABLED(CONFIG_KCSAN_PERMISSIVE))
+		KUNIT_EXPECT_FALSE(test, match);
+	else
+		KUNIT_EXPECT_TRUE(test, match);
+}
+
+__no_kcsan
+static void test_correct_barrier(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_with_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) },
+			{ test_kernel_with_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(0) },
+		},
+	};
+	bool match_expect = false;
+
+	test_struct.val[0] = 0; /* init unlocked */
+	begin_test_checks(test_kernel_with_memorder, test_kernel_with_memorder);
+	do {
+		match_expect = report_matches_any_reordered(&expect);
+	} while (!end_test_checks(match_expect));
+	KUNIT_EXPECT_FALSE(test, match_expect);
+}
+
+__no_kcsan
+static void test_missing_barrier(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_wrong_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) },
+			{ test_kernel_wrong_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(0) },
+		},
+	};
+	bool match_expect = false;
+
+	test_struct.val[0] = 0; /* init unlocked */
+	begin_test_checks(test_kernel_wrong_memorder, test_kernel_wrong_memorder);
+	do {
+		match_expect = report_matches_any_reordered(&expect);
+	} while (!end_test_checks(match_expect));
+	if (IS_ENABLED(CONFIG_KCSAN_WEAK_MEMORY))
+		KUNIT_EXPECT_TRUE(test, match_expect);
+	else
+		KUNIT_EXPECT_FALSE(test, match_expect);
+}
+
+__no_kcsan
+static void test_atomic_builtins_correct_barrier(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_atomic_builtin_with_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) },
+			{ test_kernel_atomic_builtin_with_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(0) },
+		},
+	};
+	bool match_expect = false;
+
+	test_struct.val[0] = 0; /* init unlocked */
+	begin_test_checks(test_kernel_atomic_builtin_with_memorder,
+			  test_kernel_atomic_builtin_with_memorder);
+	do {
+		match_expect = report_matches_any_reordered(&expect);
+	} while (!end_test_checks(match_expect));
+	KUNIT_EXPECT_FALSE(test, match_expect);
+}
+
+__no_kcsan
+static void test_atomic_builtins_missing_barrier(struct kunit *test)
+{
+	struct expect_report expect = {
+		.access = {
+			{ test_kernel_atomic_builtin_wrong_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) },
+			{ test_kernel_atomic_builtin_wrong_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(0) },
+		},
+	};
+	bool match_expect = false;
+
+	test_struct.val[0] = 0; /* init unlocked */
+	begin_test_checks(test_kernel_atomic_builtin_wrong_memorder,
+			  test_kernel_atomic_builtin_wrong_memorder);
+	do {
+		match_expect = report_matches_any_reordered(&expect);
+	} while (!end_test_checks(match_expect));
+	if (IS_ENABLED(CONFIG_KCSAN_WEAK_MEMORY))
+		KUNIT_EXPECT_TRUE(test, match_expect);
+	else
+		KUNIT_EXPECT_FALSE(test, match_expect);
+}
+
+/*
+ * Generate thread counts for all test cases. Values generated are in interval
+ * [2, 5] followed by exponentially increasing thread counts from 8 to 32.
+ *
+ * The thread counts are chosen to cover potentially interesting boundaries and
+ * corner cases (2 to 5), and then stress the system with larger counts.
+ */
+static const void *nthreads_gen_params(const void *prev, char *desc)
+{
+	long nthreads = (long)prev;
+
+	if (nthreads < 0 || nthreads >= 32)
+		nthreads = 0; /* stop */
+	else if (!nthreads)
+		nthreads = 2; /* initial value */
+	else if (nthreads < 5)
+		nthreads++;
+	else if (nthreads == 5)
+		nthreads = 8;
+	else
+		nthreads *= 2;
+
+	if (!preempt_model_preemptible() ||
+	    !IS_ENABLED(CONFIG_KCSAN_INTERRUPT_WATCHER)) {
+		/*
+		 * Without any preemption, keep 2 CPUs free for other tasks, one
+		 * of which is the main test case function checking for
+		 * completion or failure.
+		 */
+		const long min_unused_cpus = preempt_model_none() ? 2 : 0;
+		const long min_required_cpus = 2 + min_unused_cpus;
+
+		if (num_online_cpus() < min_required_cpus) {
+			pr_err_once("Too few online CPUs (%u < %ld) for test\n",
+				    num_online_cpus(), min_required_cpus);
+			nthreads = 0;
+		} else if (nthreads >= num_online_cpus() - min_unused_cpus) {
+			/* Use negative value to indicate last param. */
+			nthreads = -(num_online_cpus() - min_unused_cpus);
+			pr_warn_once("Limiting number of threads to %ld (only %d online CPUs)\n",
+				     -nthreads, num_online_cpus());
+		}
+	}
+
+	snprintf(desc, KUNIT_PARAM_DESC_SIZE, "threads=%ld", abs(nthreads));
+	return (void *)nthreads;
+}
+
+#define KCSAN_KUNIT_CASE(test_name) KUNIT_CASE_PARAM(test_name, nthreads_gen_params)
+static struct kunit_case kcsan_test_cases[] = {
+	KUNIT_CASE(test_barrier_nothreads),
+	KCSAN_KUNIT_CASE(test_basic),
+	KCSAN_KUNIT_CASE(test_concurrent_races),
+	KCSAN_KUNIT_CASE(test_novalue_change),
+	KCSAN_KUNIT_CASE(test_novalue_change_exception),
+	KCSAN_KUNIT_CASE(test_unknown_origin),
+	KCSAN_KUNIT_CASE(test_write_write_assume_atomic),
+	KCSAN_KUNIT_CASE(test_write_write_struct),
+	KCSAN_KUNIT_CASE(test_write_write_struct_part),
+	KCSAN_KUNIT_CASE(test_read_atomic_write_atomic),
+	KCSAN_KUNIT_CASE(test_read_plain_atomic_write),
+	KCSAN_KUNIT_CASE(test_read_plain_atomic_rmw),
+	KCSAN_KUNIT_CASE(test_zero_size_access),
+	KCSAN_KUNIT_CASE(test_data_race),
+	KCSAN_KUNIT_CASE(test_assert_exclusive_writer),
+	KCSAN_KUNIT_CASE(test_assert_exclusive_access),
+	KCSAN_KUNIT_CASE(test_assert_exclusive_access_writer),
+	KCSAN_KUNIT_CASE(test_assert_exclusive_bits_change),
+	KCSAN_KUNIT_CASE(test_assert_exclusive_bits_nochange),
+	KCSAN_KUNIT_CASE(test_assert_exclusive_writer_scoped),
+	KCSAN_KUNIT_CASE(test_assert_exclusive_access_scoped),
+	KCSAN_KUNIT_CASE(test_jiffies_noreport),
+	KCSAN_KUNIT_CASE(test_seqlock_noreport),
+	KCSAN_KUNIT_CASE(test_atomic_builtins),
+	KCSAN_KUNIT_CASE(test_1bit_value_change),
+	KCSAN_KUNIT_CASE(test_correct_barrier),
+	KCSAN_KUNIT_CASE(test_missing_barrier),
+	KCSAN_KUNIT_CASE(test_atomic_builtins_correct_barrier),
+	KCSAN_KUNIT_CASE(test_atomic_builtins_missing_barrier),
+	{},
+};
+
+/* ===== End test cases ===== */
+
+/* Concurrent accesses from interrupts. */
+__no_kcsan
+static void access_thread_timer(struct timer_list *timer)
+{
+	static atomic_t cnt = ATOMIC_INIT(0);
+	unsigned int idx;
+	void (*func)(void);
+
+	idx = (unsigned int)atomic_inc_return(&cnt) % ARRAY_SIZE(access_kernels);
+	/* Acquire potential initialization. */
+	func = smp_load_acquire(&access_kernels[idx]);
+	if (func)
+		func();
+}
+
+/* The main loop for each thread. */
+__no_kcsan
+static int access_thread(void *arg)
+{
+	struct timer_list timer;
+	unsigned int cnt = 0;
+	unsigned int idx;
+	void (*func)(void);
+
+	timer_setup_on_stack(&timer, access_thread_timer, 0);
+	do {
+		might_sleep();
+
+		if (!timer_pending(&timer))
+			mod_timer(&timer, jiffies + 1);
+		else {
+			/* Iterate through all kernels. */
+			idx = cnt++ % ARRAY_SIZE(access_kernels);
+			/* Acquire potential initialization. */
+			func = smp_load_acquire(&access_kernels[idx]);
+			if (func)
+				func();
+		}
+	} while (!torture_must_stop());
+	del_timer_sync(&timer);
+	destroy_timer_on_stack(&timer);
+
+	torture_kthread_stopping("access_thread");
+	return 0;
+}
+
+__no_kcsan
+static int test_init(struct kunit *test)
+{
+	unsigned long flags;
+	int nthreads;
+	int i;
+
+	spin_lock_irqsave(&observed.lock, flags);
+	for (i = 0; i < ARRAY_SIZE(observed.lines); ++i)
+		observed.lines[i][0] = '\0';
+	observed.nlines = 0;
+	spin_unlock_irqrestore(&observed.lock, flags);
+
+	if (strstr(test->name, "nothreads"))
+		return 0;
+
+	if (!torture_init_begin((char *)test->name, 1))
+		return -EBUSY;
+
+	if (WARN_ON(threads))
+		goto err;
+
+	for (i = 0; i < ARRAY_SIZE(access_kernels); ++i) {
+		if (WARN_ON(access_kernels[i]))
+			goto err;
+	}
+
+	nthreads = abs((long)test->param_value);
+	if (WARN_ON(!nthreads))
+		goto err;
+
+	threads = kcalloc(nthreads + 1, sizeof(struct task_struct *), GFP_KERNEL);
+	if (WARN_ON(!threads))
+		goto err;
+
+	threads[nthreads] = NULL;
+	for (i = 0; i < nthreads; ++i) {
+		if (torture_create_kthread(access_thread, NULL, threads[i]))
+			goto err;
+	}
+
+	torture_init_end();
+
+	return 0;
+
+err:
+	kfree(threads);
+	threads = NULL;
+	torture_init_end();
+	return -EINVAL;
+}
+
+__no_kcsan
+static void test_exit(struct kunit *test)
+{
+	struct task_struct **stop_thread;
+	int i;
+
+	if (strstr(test->name, "nothreads"))
+		return;
+
+	if (torture_cleanup_begin())
+		return;
+
+	for (i = 0; i < ARRAY_SIZE(access_kernels); ++i)
+		WRITE_ONCE(access_kernels[i], NULL);
+
+	if (threads) {
+		for (stop_thread = threads; *stop_thread; stop_thread++)
+			torture_stop_kthread(reader_thread, *stop_thread);
+
+		kfree(threads);
+		threads = NULL;
+	}
+
+	torture_cleanup_end();
+}
+
+__no_kcsan
+static void register_tracepoints(struct tracepoint *tp, void *ignore)
+{
+	check_trace_callback_type_console(probe_console);
+	if (!strcmp(tp->name, "console"))
+		WARN_ON(tracepoint_probe_register(tp, probe_console, NULL));
+}
+
+__no_kcsan
+static void unregister_tracepoints(struct tracepoint *tp, void *ignore)
+{
+	if (!strcmp(tp->name, "console"))
+		tracepoint_probe_unregister(tp, probe_console, NULL);
+}
+
+static int kcsan_suite_init(struct kunit_suite *suite)
+{
+	/*
+	 * Because we want to be able to build the test as a module, we need to
+	 * iterate through all known tracepoints, since the static registration
+	 * won't work here.
+	 */
+	for_each_kernel_tracepoint(register_tracepoints, NULL);
+	return 0;
+}
+
+static void kcsan_suite_exit(struct kunit_suite *suite)
+{
+	for_each_kernel_tracepoint(unregister_tracepoints, NULL);
+	tracepoint_synchronize_unregister();
+}
+
+static struct kunit_suite kcsan_test_suite = {
+	.name = "kcsan",
+	.test_cases = kcsan_test_cases,
+	.init = test_init,
+	.exit = test_exit,
+	.suite_init = kcsan_suite_init,
+	.suite_exit = kcsan_suite_exit,
+};
+
+kunit_test_suites(&kcsan_test_suite);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Marco Elver <elver@google.com>");
diff --git a/kernel/kcsan/permissive.h b/kernel/kcsan/permissive.h
new file mode 100644
index 000000000..2c01fe4a5
--- /dev/null
+++ b/kernel/kcsan/permissive.h
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Special rules for ignoring entire classes of data-racy memory accesses. None
+ * of the rules here imply that such data races are generally safe!
+ *
+ * All rules in this file can be configured via CONFIG_KCSAN_PERMISSIVE. Keep
+ * them separate from core code to make it easier to audit.
+ *
+ * Copyright (C) 2019, Google LLC.
+ */
+
+#ifndef _KERNEL_KCSAN_PERMISSIVE_H
+#define _KERNEL_KCSAN_PERMISSIVE_H
+
+#include <linux/bitops.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+
+/*
+ * Access ignore rules based on address.
+ */
+static __always_inline bool kcsan_ignore_address(const volatile void *ptr)
+{
+	if (!IS_ENABLED(CONFIG_KCSAN_PERMISSIVE))
+		return false;
+
+	/*
+	 * Data-racy bitops on current->flags are too common, ignore completely
+	 * for now.
+	 */
+	return ptr == &current->flags;
+}
+
+/*
+ * Data race ignore rules based on access type and value change patterns.
+ */
+static bool
+kcsan_ignore_data_race(size_t size, int type, u64 old, u64 new, u64 diff)
+{
+	if (!IS_ENABLED(CONFIG_KCSAN_PERMISSIVE))
+		return false;
+
+	/*
+	 * Rules here are only for plain read accesses, so that we still report
+	 * data races between plain read-write accesses.
+	 */
+	if (type || size > sizeof(long))
+		return false;
+
+	/*
+	 * A common pattern is checking/setting just 1 bit in a variable; for
+	 * example:
+	 *
+	 *	if (flags & SOME_FLAG) { ... }
+	 *
+	 * and elsewhere flags is updated concurrently:
+	 *
+	 *	flags |= SOME_OTHER_FLAG; // just 1 bit
+	 *
+	 * While it is still recommended that such accesses be marked
+	 * appropriately, in many cases these types of data races are so common
+	 * that marking them all is often unrealistic and left to maintainer
+	 * preference.
+	 *
+	 * The assumption in all cases is that with all known compiler
+	 * optimizations (including those that tear accesses), because no more
+	 * than 1 bit changed, the plain accesses are safe despite the presence
+	 * of data races.
+	 *
+	 * The rules here will ignore the data races if we observe no more than
+	 * 1 bit changed.
+	 *
+	 * Of course many operations can effecively change just 1 bit, but the
+	 * general assuption that data races involving 1-bit changes can be
+	 * tolerated still applies.
+	 *
+	 * And in case a true bug is missed, the bug likely manifests as a
+	 * reportable data race elsewhere.
+	 */
+	if (hweight64(diff) == 1) {
+		/*
+		 * Exception: Report data races where the values look like
+		 * ordinary booleans (one of them was 0 and the 0th bit was
+		 * changed) More often than not, they come with interesting
+		 * memory ordering requirements, so let's report them.
+		 */
+		if (!((!old || !new) && diff == 1))
+			return true;
+	}
+
+	return false;
+}
+
+#endif /* _KERNEL_KCSAN_PERMISSIVE_H */
diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c
new file mode 100644
index 000000000..e95ce7d7a
--- /dev/null
+++ b/kernel/kcsan/report.c
@@ -0,0 +1,715 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KCSAN reporting.
+ *
+ * Copyright (C) 2019, Google LLC.
+ */
+
+#include <linux/debug_locks.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
+#include <linux/kallsyms.h>
+#include <linux/kernel.h>
+#include <linux/lockdep.h>
+#include <linux/preempt.h>
+#include <linux/printk.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/stacktrace.h>
+
+#include "kcsan.h"
+#include "encoding.h"
+
+/*
+ * Max. number of stack entries to show in the report.
+ */
+#define NUM_STACK_ENTRIES 64
+
+/* Common access info. */
+struct access_info {
+	const volatile void	*ptr;
+	size_t			size;
+	int			access_type;
+	int			task_pid;
+	int			cpu_id;
+	unsigned long		ip;
+};
+
+/*
+ * Other thread info: communicated from other racing thread to thread that set
+ * up the watchpoint, which then prints the complete report atomically.
+ */
+struct other_info {
+	struct access_info	ai;
+	unsigned long		stack_entries[NUM_STACK_ENTRIES];
+	int			num_stack_entries;
+
+	/*
+	 * Optionally pass @current. Typically we do not need to pass @current
+	 * via @other_info since just @task_pid is sufficient. Passing @current
+	 * has additional overhead.
+	 *
+	 * To safely pass @current, we must either use get_task_struct/
+	 * put_task_struct, or stall the thread that populated @other_info.
+	 *
+	 * We cannot rely on get_task_struct/put_task_struct in case
+	 * release_report() races with a task being released, and would have to
+	 * free it in release_report(). This may result in deadlock if we want
+	 * to use KCSAN on the allocators.
+	 *
+	 * Since we also want to reliably print held locks for
+	 * CONFIG_KCSAN_VERBOSE, the current implementation stalls the thread
+	 * that populated @other_info until it has been consumed.
+	 */
+	struct task_struct	*task;
+};
+
+/*
+ * To never block any producers of struct other_info, we need as many elements
+ * as we have watchpoints (upper bound on concurrent races to report).
+ */
+static struct other_info other_infos[CONFIG_KCSAN_NUM_WATCHPOINTS + NUM_SLOTS-1];
+
+/*
+ * Information about reported races; used to rate limit reporting.
+ */
+struct report_time {
+	/*
+	 * The last time the race was reported.
+	 */
+	unsigned long time;
+
+	/*
+	 * The frames of the 2 threads; if only 1 thread is known, one frame
+	 * will be 0.
+	 */
+	unsigned long frame1;
+	unsigned long frame2;
+};
+
+/*
+ * Since we also want to be able to debug allocators with KCSAN, to avoid
+ * deadlock, report_times cannot be dynamically resized with krealloc in
+ * rate_limit_report.
+ *
+ * Therefore, we use a fixed-size array, which at most will occupy a page. This
+ * still adequately rate limits reports, assuming that a) number of unique data
+ * races is not excessive, and b) occurrence of unique races within the
+ * same time window is limited.
+ */
+#define REPORT_TIMES_MAX (PAGE_SIZE / sizeof(struct report_time))
+#define REPORT_TIMES_SIZE                                                      \
+	(CONFIG_KCSAN_REPORT_ONCE_IN_MS > REPORT_TIMES_MAX ?                   \
+		 REPORT_TIMES_MAX :                                            \
+		 CONFIG_KCSAN_REPORT_ONCE_IN_MS)
+static struct report_time report_times[REPORT_TIMES_SIZE];
+
+/*
+ * Spinlock serializing report generation, and access to @other_infos. Although
+ * it could make sense to have a finer-grained locking story for @other_infos,
+ * report generation needs to be serialized either way, so not much is gained.
+ */
+static DEFINE_RAW_SPINLOCK(report_lock);
+
+/*
+ * Checks if the race identified by thread frames frame1 and frame2 has
+ * been reported since (now - KCSAN_REPORT_ONCE_IN_MS).
+ */
+static bool rate_limit_report(unsigned long frame1, unsigned long frame2)
+{
+	struct report_time *use_entry = &report_times[0];
+	unsigned long invalid_before;
+	int i;
+
+	BUILD_BUG_ON(CONFIG_KCSAN_REPORT_ONCE_IN_MS != 0 && REPORT_TIMES_SIZE == 0);
+
+	if (CONFIG_KCSAN_REPORT_ONCE_IN_MS == 0)
+		return false;
+
+	invalid_before = jiffies - msecs_to_jiffies(CONFIG_KCSAN_REPORT_ONCE_IN_MS);
+
+	/* Check if a matching race report exists. */
+	for (i = 0; i < REPORT_TIMES_SIZE; ++i) {
+		struct report_time *rt = &report_times[i];
+
+		/*
+		 * Must always select an entry for use to store info as we
+		 * cannot resize report_times; at the end of the scan, use_entry
+		 * will be the oldest entry, which ideally also happened before
+		 * KCSAN_REPORT_ONCE_IN_MS ago.
+		 */
+		if (time_before(rt->time, use_entry->time))
+			use_entry = rt;
+
+		/*
+		 * Initially, no need to check any further as this entry as well
+		 * as following entries have never been used.
+		 */
+		if (rt->time == 0)
+			break;
+
+		/* Check if entry expired. */
+		if (time_before(rt->time, invalid_before))
+			continue; /* before KCSAN_REPORT_ONCE_IN_MS ago */
+
+		/* Reported recently, check if race matches. */
+		if ((rt->frame1 == frame1 && rt->frame2 == frame2) ||
+		    (rt->frame1 == frame2 && rt->frame2 == frame1))
+			return true;
+	}
+
+	use_entry->time = jiffies;
+	use_entry->frame1 = frame1;
+	use_entry->frame2 = frame2;
+	return false;
+}
+
+/*
+ * Special rules to skip reporting.
+ */
+static bool
+skip_report(enum kcsan_value_change value_change, unsigned long top_frame)
+{
+	/* Should never get here if value_change==FALSE. */
+	WARN_ON_ONCE(value_change == KCSAN_VALUE_CHANGE_FALSE);
+
+	/*
+	 * The first call to skip_report always has value_change==TRUE, since we
+	 * cannot know the value written of an instrumented access. For the 2nd
+	 * call there are 6 cases with CONFIG_KCSAN_REPORT_VALUE_CHANGE_ONLY:
+	 *
+	 * 1. read watchpoint, conflicting write (value_change==TRUE): report;
+	 * 2. read watchpoint, conflicting write (value_change==MAYBE): skip;
+	 * 3. write watchpoint, conflicting write (value_change==TRUE): report;
+	 * 4. write watchpoint, conflicting write (value_change==MAYBE): skip;
+	 * 5. write watchpoint, conflicting read (value_change==MAYBE): skip;
+	 * 6. write watchpoint, conflicting read (value_change==TRUE): report;
+	 *
+	 * Cases 1-4 are intuitive and expected; case 5 ensures we do not report
+	 * data races where the write may have rewritten the same value; case 6
+	 * is possible either if the size is larger than what we check value
+	 * changes for or the access type is KCSAN_ACCESS_ASSERT.
+	 */
+	if (IS_ENABLED(CONFIG_KCSAN_REPORT_VALUE_CHANGE_ONLY) &&
+	    value_change == KCSAN_VALUE_CHANGE_MAYBE) {
+		/*
+		 * The access is a write, but the data value did not change.
+		 *
+		 * We opt-out of this filter for certain functions at request of
+		 * maintainers.
+		 */
+		char buf[64];
+		int len = scnprintf(buf, sizeof(buf), "%ps", (void *)top_frame);
+
+		if (!strnstr(buf, "rcu_", len) &&
+		    !strnstr(buf, "_rcu", len) &&
+		    !strnstr(buf, "_srcu", len))
+			return true;
+	}
+
+	return kcsan_skip_report_debugfs(top_frame);
+}
+
+static const char *get_access_type(int type)
+{
+	if (type & KCSAN_ACCESS_ASSERT) {
+		if (type & KCSAN_ACCESS_SCOPED) {
+			if (type & KCSAN_ACCESS_WRITE)
+				return "assert no accesses (reordered)";
+			else
+				return "assert no writes (reordered)";
+		} else {
+			if (type & KCSAN_ACCESS_WRITE)
+				return "assert no accesses";
+			else
+				return "assert no writes";
+		}
+	}
+
+	switch (type) {
+	case 0:
+		return "read";
+	case KCSAN_ACCESS_ATOMIC:
+		return "read (marked)";
+	case KCSAN_ACCESS_WRITE:
+		return "write";
+	case KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC:
+		return "write (marked)";
+	case KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE:
+		return "read-write";
+	case KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC:
+		return "read-write (marked)";
+	case KCSAN_ACCESS_SCOPED:
+		return "read (reordered)";
+	case KCSAN_ACCESS_SCOPED | KCSAN_ACCESS_ATOMIC:
+		return "read (marked, reordered)";
+	case KCSAN_ACCESS_SCOPED | KCSAN_ACCESS_WRITE:
+		return "write (reordered)";
+	case KCSAN_ACCESS_SCOPED | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC:
+		return "write (marked, reordered)";
+	case KCSAN_ACCESS_SCOPED | KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE:
+		return "read-write (reordered)";
+	case KCSAN_ACCESS_SCOPED | KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC:
+		return "read-write (marked, reordered)";
+	default:
+		BUG();
+	}
+}
+
+static const char *get_bug_type(int type)
+{
+	return (type & KCSAN_ACCESS_ASSERT) != 0 ? "assert: race" : "data-race";
+}
+
+/* Return thread description: in task or interrupt. */
+static const char *get_thread_desc(int task_id)
+{
+	if (task_id != -1) {
+		static char buf[32]; /* safe: protected by report_lock */
+
+		snprintf(buf, sizeof(buf), "task %i", task_id);
+		return buf;
+	}
+	return "interrupt";
+}
+
+/* Helper to skip KCSAN-related functions in stack-trace. */
+static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries)
+{
+	char buf[64];
+	char *cur;
+	int len, skip;
+
+	for (skip = 0; skip < num_entries; ++skip) {
+		len = scnprintf(buf, sizeof(buf), "%ps", (void *)stack_entries[skip]);
+
+		/* Never show tsan_* or {read,write}_once_size. */
+		if (strnstr(buf, "tsan_", len) ||
+		    strnstr(buf, "_once_size", len))
+			continue;
+
+		cur = strnstr(buf, "kcsan_", len);
+		if (cur) {
+			cur += strlen("kcsan_");
+			if (!str_has_prefix(cur, "test"))
+				continue; /* KCSAN runtime function. */
+			/* KCSAN related test. */
+		}
+
+		/*
+		 * No match for runtime functions -- @skip entries to skip to
+		 * get to first frame of interest.
+		 */
+		break;
+	}
+
+	return skip;
+}
+
+/*
+ * Skips to the first entry that matches the function of @ip, and then replaces
+ * that entry with @ip, returning the entries to skip with @replaced containing
+ * the replaced entry.
+ */
+static int
+replace_stack_entry(unsigned long stack_entries[], int num_entries, unsigned long ip,
+		    unsigned long *replaced)
+{
+	unsigned long symbolsize, offset;
+	unsigned long target_func;
+	int skip;
+
+	if (kallsyms_lookup_size_offset(ip, &symbolsize, &offset))
+		target_func = ip - offset;
+	else
+		goto fallback;
+
+	for (skip = 0; skip < num_entries; ++skip) {
+		unsigned long func = stack_entries[skip];
+
+		if (!kallsyms_lookup_size_offset(func, &symbolsize, &offset))
+			goto fallback;
+		func -= offset;
+
+		if (func == target_func) {
+			*replaced = stack_entries[skip];
+			stack_entries[skip] = ip;
+			return skip;
+		}
+	}
+
+fallback:
+	/* Should not happen; the resulting stack trace is likely misleading. */
+	WARN_ONCE(1, "Cannot find frame for %pS in stack trace", (void *)ip);
+	return get_stack_skipnr(stack_entries, num_entries);
+}
+
+static int
+sanitize_stack_entries(unsigned long stack_entries[], int num_entries, unsigned long ip,
+		       unsigned long *replaced)
+{
+	return ip ? replace_stack_entry(stack_entries, num_entries, ip, replaced) :
+			  get_stack_skipnr(stack_entries, num_entries);
+}
+
+/* Compares symbolized strings of addr1 and addr2. */
+static int sym_strcmp(void *addr1, void *addr2)
+{
+	char buf1[64];
+	char buf2[64];
+
+	snprintf(buf1, sizeof(buf1), "%pS", addr1);
+	snprintf(buf2, sizeof(buf2), "%pS", addr2);
+
+	return strncmp(buf1, buf2, sizeof(buf1));
+}
+
+static void
+print_stack_trace(unsigned long stack_entries[], int num_entries, unsigned long reordered_to)
+{
+	stack_trace_print(stack_entries, num_entries, 0);
+	if (reordered_to)
+		pr_err("  |\n  +-> reordered to: %pS\n", (void *)reordered_to);
+}
+
+static void print_verbose_info(struct task_struct *task)
+{
+	if (!task)
+		return;
+
+	/* Restore IRQ state trace for printing. */
+	kcsan_restore_irqtrace(task);
+
+	pr_err("\n");
+	debug_show_held_locks(task);
+	print_irqtrace_events(task);
+}
+
+static void print_report(enum kcsan_value_change value_change,
+			 const struct access_info *ai,
+			 struct other_info *other_info,
+			 u64 old, u64 new, u64 mask)
+{
+	unsigned long reordered_to = 0;
+	unsigned long stack_entries[NUM_STACK_ENTRIES] = { 0 };
+	int num_stack_entries = stack_trace_save(stack_entries, NUM_STACK_ENTRIES, 1);
+	int skipnr = sanitize_stack_entries(stack_entries, num_stack_entries, ai->ip, &reordered_to);
+	unsigned long this_frame = stack_entries[skipnr];
+	unsigned long other_reordered_to = 0;
+	unsigned long other_frame = 0;
+	int other_skipnr = 0; /* silence uninit warnings */
+
+	/*
+	 * Must check report filter rules before starting to print.
+	 */
+	if (skip_report(KCSAN_VALUE_CHANGE_TRUE, stack_entries[skipnr]))
+		return;
+
+	if (other_info) {
+		other_skipnr = sanitize_stack_entries(other_info->stack_entries,
+						      other_info->num_stack_entries,
+						      other_info->ai.ip, &other_reordered_to);
+		other_frame = other_info->stack_entries[other_skipnr];
+
+		/* @value_change is only known for the other thread */
+		if (skip_report(value_change, other_frame))
+			return;
+	}
+
+	if (rate_limit_report(this_frame, other_frame))
+		return;
+
+	/* Print report header. */
+	pr_err("==================================================================\n");
+	if (other_info) {
+		int cmp;
+
+		/*
+		 * Order functions lexographically for consistent bug titles.
+		 * Do not print offset of functions to keep title short.
+		 */
+		cmp = sym_strcmp((void *)other_frame, (void *)this_frame);
+		pr_err("BUG: KCSAN: %s in %ps / %ps\n",
+		       get_bug_type(ai->access_type | other_info->ai.access_type),
+		       (void *)(cmp < 0 ? other_frame : this_frame),
+		       (void *)(cmp < 0 ? this_frame : other_frame));
+	} else {
+		pr_err("BUG: KCSAN: %s in %pS\n", get_bug_type(ai->access_type),
+		       (void *)this_frame);
+	}
+
+	pr_err("\n");
+
+	/* Print information about the racing accesses. */
+	if (other_info) {
+		pr_err("%s to 0x%px of %zu bytes by %s on cpu %i:\n",
+		       get_access_type(other_info->ai.access_type), other_info->ai.ptr,
+		       other_info->ai.size, get_thread_desc(other_info->ai.task_pid),
+		       other_info->ai.cpu_id);
+
+		/* Print the other thread's stack trace. */
+		print_stack_trace(other_info->stack_entries + other_skipnr,
+				  other_info->num_stack_entries - other_skipnr,
+				  other_reordered_to);
+		if (IS_ENABLED(CONFIG_KCSAN_VERBOSE))
+			print_verbose_info(other_info->task);
+
+		pr_err("\n");
+		pr_err("%s to 0x%px of %zu bytes by %s on cpu %i:\n",
+		       get_access_type(ai->access_type), ai->ptr, ai->size,
+		       get_thread_desc(ai->task_pid), ai->cpu_id);
+	} else {
+		pr_err("race at unknown origin, with %s to 0x%px of %zu bytes by %s on cpu %i:\n",
+		       get_access_type(ai->access_type), ai->ptr, ai->size,
+		       get_thread_desc(ai->task_pid), ai->cpu_id);
+	}
+	/* Print stack trace of this thread. */
+	print_stack_trace(stack_entries + skipnr, num_stack_entries - skipnr, reordered_to);
+	if (IS_ENABLED(CONFIG_KCSAN_VERBOSE))
+		print_verbose_info(current);
+
+	/* Print observed value change. */
+	if (ai->size <= 8) {
+		int hex_len = ai->size * 2;
+		u64 diff = old ^ new;
+
+		if (mask)
+			diff &= mask;
+		if (diff) {
+			pr_err("\n");
+			pr_err("value changed: 0x%0*llx -> 0x%0*llx\n",
+			       hex_len, old, hex_len, new);
+			if (mask) {
+				pr_err(" bits changed: 0x%0*llx with mask 0x%0*llx\n",
+				       hex_len, diff, hex_len, mask);
+			}
+		}
+	}
+
+	/* Print report footer. */
+	pr_err("\n");
+	pr_err("Reported by Kernel Concurrency Sanitizer on:\n");
+	dump_stack_print_info(KERN_DEFAULT);
+	pr_err("==================================================================\n");
+
+	check_panic_on_warn("KCSAN");
+}
+
+static void release_report(unsigned long *flags, struct other_info *other_info)
+{
+	/*
+	 * Use size to denote valid/invalid, since KCSAN entirely ignores
+	 * 0-sized accesses.
+	 */
+	other_info->ai.size = 0;
+	raw_spin_unlock_irqrestore(&report_lock, *flags);
+}
+
+/*
+ * Sets @other_info->task and awaits consumption of @other_info.
+ *
+ * Precondition: report_lock is held.
+ * Postcondition: report_lock is held.
+ */
+static void set_other_info_task_blocking(unsigned long *flags,
+					 const struct access_info *ai,
+					 struct other_info *other_info)
+{
+	/*
+	 * We may be instrumenting a code-path where current->state is already
+	 * something other than TASK_RUNNING.
+	 */
+	const bool is_running = task_is_running(current);
+	/*
+	 * To avoid deadlock in case we are in an interrupt here and this is a
+	 * race with a task on the same CPU (KCSAN_INTERRUPT_WATCHER), provide a
+	 * timeout to ensure this works in all contexts.
+	 *
+	 * Await approximately the worst case delay of the reporting thread (if
+	 * we are not interrupted).
+	 */
+	int timeout = max(kcsan_udelay_task, kcsan_udelay_interrupt);
+
+	other_info->task = current;
+	do {
+		if (is_running) {
+			/*
+			 * Let lockdep know the real task is sleeping, to print
+			 * the held locks (recall we turned lockdep off, so
+			 * locking/unlocking @report_lock won't be recorded).
+			 */
+			set_current_state(TASK_UNINTERRUPTIBLE);
+		}
+		raw_spin_unlock_irqrestore(&report_lock, *flags);
+		/*
+		 * We cannot call schedule() since we also cannot reliably
+		 * determine if sleeping here is permitted -- see in_atomic().
+		 */
+
+		udelay(1);
+		raw_spin_lock_irqsave(&report_lock, *flags);
+		if (timeout-- < 0) {
+			/*
+			 * Abort. Reset @other_info->task to NULL, since it
+			 * appears the other thread is still going to consume
+			 * it. It will result in no verbose info printed for
+			 * this task.
+			 */
+			other_info->task = NULL;
+			break;
+		}
+		/*
+		 * If invalid, or @ptr nor @current matches, then @other_info
+		 * has been consumed and we may continue. If not, retry.
+		 */
+	} while (other_info->ai.size && other_info->ai.ptr == ai->ptr &&
+		 other_info->task == current);
+	if (is_running)
+		set_current_state(TASK_RUNNING);
+}
+
+/* Populate @other_info; requires that the provided @other_info not in use. */
+static void prepare_report_producer(unsigned long *flags,
+				    const struct access_info *ai,
+				    struct other_info *other_info)
+{
+	raw_spin_lock_irqsave(&report_lock, *flags);
+
+	/*
+	 * The same @other_infos entry cannot be used concurrently, because
+	 * there is a one-to-one mapping to watchpoint slots (@watchpoints in
+	 * core.c), and a watchpoint is only released for reuse after reporting
+	 * is done by the consumer of @other_info. Therefore, it is impossible
+	 * for another concurrent prepare_report_producer() to set the same
+	 * @other_info, and are guaranteed exclusivity for the @other_infos
+	 * entry pointed to by @other_info.
+	 *
+	 * To check this property holds, size should never be non-zero here,
+	 * because every consumer of struct other_info resets size to 0 in
+	 * release_report().
+	 */
+	WARN_ON(other_info->ai.size);
+
+	other_info->ai = *ai;
+	other_info->num_stack_entries = stack_trace_save(other_info->stack_entries, NUM_STACK_ENTRIES, 2);
+
+	if (IS_ENABLED(CONFIG_KCSAN_VERBOSE))
+		set_other_info_task_blocking(flags, ai, other_info);
+
+	raw_spin_unlock_irqrestore(&report_lock, *flags);
+}
+
+/* Awaits producer to fill @other_info and then returns. */
+static bool prepare_report_consumer(unsigned long *flags,
+				    const struct access_info *ai,
+				    struct other_info *other_info)
+{
+
+	raw_spin_lock_irqsave(&report_lock, *flags);
+	while (!other_info->ai.size) { /* Await valid @other_info. */
+		raw_spin_unlock_irqrestore(&report_lock, *flags);
+		cpu_relax();
+		raw_spin_lock_irqsave(&report_lock, *flags);
+	}
+
+	/* Should always have a matching access based on watchpoint encoding. */
+	if (WARN_ON(!matching_access((unsigned long)other_info->ai.ptr & WATCHPOINT_ADDR_MASK, other_info->ai.size,
+				     (unsigned long)ai->ptr & WATCHPOINT_ADDR_MASK, ai->size)))
+		goto discard;
+
+	if (!matching_access((unsigned long)other_info->ai.ptr, other_info->ai.size,
+			     (unsigned long)ai->ptr, ai->size)) {
+		/*
+		 * If the actual accesses to not match, this was a false
+		 * positive due to watchpoint encoding.
+		 */
+		atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_ENCODING_FALSE_POSITIVES]);
+		goto discard;
+	}
+
+	return true;
+
+discard:
+	release_report(flags, other_info);
+	return false;
+}
+
+static struct access_info prepare_access_info(const volatile void *ptr, size_t size,
+					      int access_type, unsigned long ip)
+{
+	return (struct access_info) {
+		.ptr		= ptr,
+		.size		= size,
+		.access_type	= access_type,
+		.task_pid	= in_task() ? task_pid_nr(current) : -1,
+		.cpu_id		= raw_smp_processor_id(),
+		/* Only replace stack entry with @ip if scoped access. */
+		.ip		= (access_type & KCSAN_ACCESS_SCOPED) ? ip : 0,
+	};
+}
+
+void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_type,
+			   unsigned long ip, int watchpoint_idx)
+{
+	const struct access_info ai = prepare_access_info(ptr, size, access_type, ip);
+	unsigned long flags;
+
+	kcsan_disable_current();
+	lockdep_off(); /* See kcsan_report_known_origin(). */
+
+	prepare_report_producer(&flags, &ai, &other_infos[watchpoint_idx]);
+
+	lockdep_on();
+	kcsan_enable_current();
+}
+
+void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access_type,
+			       unsigned long ip, enum kcsan_value_change value_change,
+			       int watchpoint_idx, u64 old, u64 new, u64 mask)
+{
+	const struct access_info ai = prepare_access_info(ptr, size, access_type, ip);
+	struct other_info *other_info = &other_infos[watchpoint_idx];
+	unsigned long flags = 0;
+
+	kcsan_disable_current();
+	/*
+	 * Because we may generate reports when we're in scheduler code, the use
+	 * of printk() could deadlock. Until such time that all printing code
+	 * called in print_report() is scheduler-safe, accept the risk, and just
+	 * get our message out. As such, also disable lockdep to hide the
+	 * warning, and avoid disabling lockdep for the rest of the kernel.
+	 */
+	lockdep_off();
+
+	if (!prepare_report_consumer(&flags, &ai, other_info))
+		goto out;
+	/*
+	 * Never report if value_change is FALSE, only when it is
+	 * either TRUE or MAYBE. In case of MAYBE, further filtering may
+	 * be done once we know the full stack trace in print_report().
+	 */
+	if (value_change != KCSAN_VALUE_CHANGE_FALSE)
+		print_report(value_change, &ai, other_info, old, new, mask);
+
+	release_report(&flags, other_info);
+out:
+	lockdep_on();
+	kcsan_enable_current();
+}
+
+void kcsan_report_unknown_origin(const volatile void *ptr, size_t size, int access_type,
+				 unsigned long ip, u64 old, u64 new, u64 mask)
+{
+	const struct access_info ai = prepare_access_info(ptr, size, access_type, ip);
+	unsigned long flags;
+
+	kcsan_disable_current();
+	lockdep_off(); /* See kcsan_report_known_origin(). */
+
+	raw_spin_lock_irqsave(&report_lock, flags);
+	print_report(KCSAN_VALUE_CHANGE_TRUE, &ai, NULL, old, new, mask);
+	raw_spin_unlock_irqrestore(&report_lock, flags);
+
+	lockdep_on();
+	kcsan_enable_current();
+}
diff --git a/kernel/kcsan/selftest.c b/kernel/kcsan/selftest.c
new file mode 100644
index 000000000..00cdf8fa5
--- /dev/null
+++ b/kernel/kcsan/selftest.c
@@ -0,0 +1,272 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KCSAN short boot-time selftests.
+ *
+ * Copyright (C) 2019, Google LLC.
+ */
+
+#define pr_fmt(fmt) "kcsan: " fmt
+
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/init.h>
+#include <linux/kcsan-checks.h>
+#include <linux/kernel.h>
+#include <linux/printk.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#include "encoding.h"
+
+#define ITERS_PER_TEST 2000
+
+/* Test requirements. */
+static bool __init test_requires(void)
+{
+	/* random should be initialized for the below tests */
+	return get_random_u32() + get_random_u32() != 0;
+}
+
+/*
+ * Test watchpoint encode and decode: check that encoding some access's info,
+ * and then subsequent decode preserves the access's info.
+ */
+static bool __init test_encode_decode(void)
+{
+	int i;
+
+	for (i = 0; i < ITERS_PER_TEST; ++i) {
+		size_t size = prandom_u32_max(MAX_ENCODABLE_SIZE) + 1;
+		bool is_write = !!prandom_u32_max(2);
+		unsigned long verif_masked_addr;
+		long encoded_watchpoint;
+		bool verif_is_write;
+		unsigned long addr;
+		size_t verif_size;
+
+		get_random_bytes(&addr, sizeof(addr));
+		if (addr < PAGE_SIZE)
+			addr = PAGE_SIZE;
+
+		if (WARN_ON(!check_encodable(addr, size)))
+			return false;
+
+		encoded_watchpoint = encode_watchpoint(addr, size, is_write);
+
+		/* Check special watchpoints */
+		if (WARN_ON(decode_watchpoint(INVALID_WATCHPOINT, &verif_masked_addr, &verif_size, &verif_is_write)))
+			return false;
+		if (WARN_ON(decode_watchpoint(CONSUMED_WATCHPOINT, &verif_masked_addr, &verif_size, &verif_is_write)))
+			return false;
+
+		/* Check decoding watchpoint returns same data */
+		if (WARN_ON(!decode_watchpoint(encoded_watchpoint, &verif_masked_addr, &verif_size, &verif_is_write)))
+			return false;
+		if (WARN_ON(verif_masked_addr != (addr & WATCHPOINT_ADDR_MASK)))
+			goto fail;
+		if (WARN_ON(verif_size != size))
+			goto fail;
+		if (WARN_ON(is_write != verif_is_write))
+			goto fail;
+
+		continue;
+fail:
+		pr_err("%s fail: %s %zu bytes @ %lx -> encoded: %lx -> %s %zu bytes @ %lx\n",
+		       __func__, is_write ? "write" : "read", size, addr, encoded_watchpoint,
+		       verif_is_write ? "write" : "read", verif_size, verif_masked_addr);
+		return false;
+	}
+
+	return true;
+}
+
+/* Test access matching function. */
+static bool __init test_matching_access(void)
+{
+	if (WARN_ON(!matching_access(10, 1, 10, 1)))
+		return false;
+	if (WARN_ON(!matching_access(10, 2, 11, 1)))
+		return false;
+	if (WARN_ON(!matching_access(10, 1, 9, 2)))
+		return false;
+	if (WARN_ON(matching_access(10, 1, 11, 1)))
+		return false;
+	if (WARN_ON(matching_access(9, 1, 10, 1)))
+		return false;
+
+	/*
+	 * An access of size 0 could match another access, as demonstrated here.
+	 * Rather than add more comparisons to 'matching_access()', which would
+	 * end up in the fast-path for *all* checks, check_access() simply
+	 * returns for all accesses of size 0.
+	 */
+	if (WARN_ON(!matching_access(8, 8, 12, 0)))
+		return false;
+
+	return true;
+}
+
+/*
+ * Correct memory barrier instrumentation is critical to avoiding false
+ * positives: simple test to check at boot certain barriers are always properly
+ * instrumented. See kcsan_test for a more complete test.
+ */
+static DEFINE_SPINLOCK(test_spinlock);
+static bool __init test_barrier(void)
+{
+#ifdef CONFIG_KCSAN_WEAK_MEMORY
+	struct kcsan_scoped_access *reorder_access = &current->kcsan_ctx.reorder_access;
+#else
+	struct kcsan_scoped_access *reorder_access = NULL;
+#endif
+	bool ret = true;
+	arch_spinlock_t arch_spinlock = __ARCH_SPIN_LOCK_UNLOCKED;
+	atomic_t dummy;
+	long test_var;
+
+	if (!reorder_access || !IS_ENABLED(CONFIG_SMP))
+		return true;
+
+#define __KCSAN_CHECK_BARRIER(access_type, barrier, name)					\
+	do {											\
+		reorder_access->type = (access_type) | KCSAN_ACCESS_SCOPED;			\
+		reorder_access->size = 1;							\
+		barrier;									\
+		if (reorder_access->size != 0) {						\
+			pr_err("improperly instrumented type=(" #access_type "): " name "\n");	\
+			ret = false;								\
+		}										\
+	} while (0)
+#define KCSAN_CHECK_READ_BARRIER(b)  __KCSAN_CHECK_BARRIER(0, b, #b)
+#define KCSAN_CHECK_WRITE_BARRIER(b) __KCSAN_CHECK_BARRIER(KCSAN_ACCESS_WRITE, b, #b)
+#define KCSAN_CHECK_RW_BARRIER(b)    __KCSAN_CHECK_BARRIER(KCSAN_ACCESS_WRITE | KCSAN_ACCESS_COMPOUND, b, #b)
+
+	kcsan_nestable_atomic_begin(); /* No watchpoints in called functions. */
+
+	KCSAN_CHECK_READ_BARRIER(mb());
+	KCSAN_CHECK_READ_BARRIER(rmb());
+	KCSAN_CHECK_READ_BARRIER(smp_mb());
+	KCSAN_CHECK_READ_BARRIER(smp_rmb());
+	KCSAN_CHECK_READ_BARRIER(dma_rmb());
+	KCSAN_CHECK_READ_BARRIER(smp_mb__before_atomic());
+	KCSAN_CHECK_READ_BARRIER(smp_mb__after_atomic());
+	KCSAN_CHECK_READ_BARRIER(smp_mb__after_spinlock());
+	KCSAN_CHECK_READ_BARRIER(smp_store_mb(test_var, 0));
+	KCSAN_CHECK_READ_BARRIER(smp_store_release(&test_var, 0));
+	KCSAN_CHECK_READ_BARRIER(xchg(&test_var, 0));
+	KCSAN_CHECK_READ_BARRIER(xchg_release(&test_var, 0));
+	KCSAN_CHECK_READ_BARRIER(cmpxchg(&test_var, 0,  0));
+	KCSAN_CHECK_READ_BARRIER(cmpxchg_release(&test_var, 0,  0));
+	KCSAN_CHECK_READ_BARRIER(atomic_set_release(&dummy, 0));
+	KCSAN_CHECK_READ_BARRIER(atomic_add_return(1, &dummy));
+	KCSAN_CHECK_READ_BARRIER(atomic_add_return_release(1, &dummy));
+	KCSAN_CHECK_READ_BARRIER(atomic_fetch_add(1, &dummy));
+	KCSAN_CHECK_READ_BARRIER(atomic_fetch_add_release(1, &dummy));
+	KCSAN_CHECK_READ_BARRIER(test_and_set_bit(0, &test_var));
+	KCSAN_CHECK_READ_BARRIER(test_and_clear_bit(0, &test_var));
+	KCSAN_CHECK_READ_BARRIER(test_and_change_bit(0, &test_var));
+	KCSAN_CHECK_READ_BARRIER(clear_bit_unlock(0, &test_var));
+	KCSAN_CHECK_READ_BARRIER(__clear_bit_unlock(0, &test_var));
+	arch_spin_lock(&arch_spinlock);
+	KCSAN_CHECK_READ_BARRIER(arch_spin_unlock(&arch_spinlock));
+	spin_lock(&test_spinlock);
+	KCSAN_CHECK_READ_BARRIER(spin_unlock(&test_spinlock));
+
+	KCSAN_CHECK_WRITE_BARRIER(mb());
+	KCSAN_CHECK_WRITE_BARRIER(wmb());
+	KCSAN_CHECK_WRITE_BARRIER(smp_mb());
+	KCSAN_CHECK_WRITE_BARRIER(smp_wmb());
+	KCSAN_CHECK_WRITE_BARRIER(dma_wmb());
+	KCSAN_CHECK_WRITE_BARRIER(smp_mb__before_atomic());
+	KCSAN_CHECK_WRITE_BARRIER(smp_mb__after_atomic());
+	KCSAN_CHECK_WRITE_BARRIER(smp_mb__after_spinlock());
+	KCSAN_CHECK_WRITE_BARRIER(smp_store_mb(test_var, 0));
+	KCSAN_CHECK_WRITE_BARRIER(smp_store_release(&test_var, 0));
+	KCSAN_CHECK_WRITE_BARRIER(xchg(&test_var, 0));
+	KCSAN_CHECK_WRITE_BARRIER(xchg_release(&test_var, 0));
+	KCSAN_CHECK_WRITE_BARRIER(cmpxchg(&test_var, 0,  0));
+	KCSAN_CHECK_WRITE_BARRIER(cmpxchg_release(&test_var, 0,  0));
+	KCSAN_CHECK_WRITE_BARRIER(atomic_set_release(&dummy, 0));
+	KCSAN_CHECK_WRITE_BARRIER(atomic_add_return(1, &dummy));
+	KCSAN_CHECK_WRITE_BARRIER(atomic_add_return_release(1, &dummy));
+	KCSAN_CHECK_WRITE_BARRIER(atomic_fetch_add(1, &dummy));
+	KCSAN_CHECK_WRITE_BARRIER(atomic_fetch_add_release(1, &dummy));
+	KCSAN_CHECK_WRITE_BARRIER(test_and_set_bit(0, &test_var));
+	KCSAN_CHECK_WRITE_BARRIER(test_and_clear_bit(0, &test_var));
+	KCSAN_CHECK_WRITE_BARRIER(test_and_change_bit(0, &test_var));
+	KCSAN_CHECK_WRITE_BARRIER(clear_bit_unlock(0, &test_var));
+	KCSAN_CHECK_WRITE_BARRIER(__clear_bit_unlock(0, &test_var));
+	arch_spin_lock(&arch_spinlock);
+	KCSAN_CHECK_WRITE_BARRIER(arch_spin_unlock(&arch_spinlock));
+	spin_lock(&test_spinlock);
+	KCSAN_CHECK_WRITE_BARRIER(spin_unlock(&test_spinlock));
+
+	KCSAN_CHECK_RW_BARRIER(mb());
+	KCSAN_CHECK_RW_BARRIER(wmb());
+	KCSAN_CHECK_RW_BARRIER(rmb());
+	KCSAN_CHECK_RW_BARRIER(smp_mb());
+	KCSAN_CHECK_RW_BARRIER(smp_wmb());
+	KCSAN_CHECK_RW_BARRIER(smp_rmb());
+	KCSAN_CHECK_RW_BARRIER(dma_wmb());
+	KCSAN_CHECK_RW_BARRIER(dma_rmb());
+	KCSAN_CHECK_RW_BARRIER(smp_mb__before_atomic());
+	KCSAN_CHECK_RW_BARRIER(smp_mb__after_atomic());
+	KCSAN_CHECK_RW_BARRIER(smp_mb__after_spinlock());
+	KCSAN_CHECK_RW_BARRIER(smp_store_mb(test_var, 0));
+	KCSAN_CHECK_RW_BARRIER(smp_store_release(&test_var, 0));
+	KCSAN_CHECK_RW_BARRIER(xchg(&test_var, 0));
+	KCSAN_CHECK_RW_BARRIER(xchg_release(&test_var, 0));
+	KCSAN_CHECK_RW_BARRIER(cmpxchg(&test_var, 0,  0));
+	KCSAN_CHECK_RW_BARRIER(cmpxchg_release(&test_var, 0,  0));
+	KCSAN_CHECK_RW_BARRIER(atomic_set_release(&dummy, 0));
+	KCSAN_CHECK_RW_BARRIER(atomic_add_return(1, &dummy));
+	KCSAN_CHECK_RW_BARRIER(atomic_add_return_release(1, &dummy));
+	KCSAN_CHECK_RW_BARRIER(atomic_fetch_add(1, &dummy));
+	KCSAN_CHECK_RW_BARRIER(atomic_fetch_add_release(1, &dummy));
+	KCSAN_CHECK_RW_BARRIER(test_and_set_bit(0, &test_var));
+	KCSAN_CHECK_RW_BARRIER(test_and_clear_bit(0, &test_var));
+	KCSAN_CHECK_RW_BARRIER(test_and_change_bit(0, &test_var));
+	KCSAN_CHECK_RW_BARRIER(clear_bit_unlock(0, &test_var));
+	KCSAN_CHECK_RW_BARRIER(__clear_bit_unlock(0, &test_var));
+	arch_spin_lock(&arch_spinlock);
+	KCSAN_CHECK_RW_BARRIER(arch_spin_unlock(&arch_spinlock));
+	spin_lock(&test_spinlock);
+	KCSAN_CHECK_RW_BARRIER(spin_unlock(&test_spinlock));
+
+#ifdef clear_bit_unlock_is_negative_byte
+	KCSAN_CHECK_RW_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var));
+	KCSAN_CHECK_READ_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var));
+	KCSAN_CHECK_WRITE_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var));
+#endif
+	kcsan_nestable_atomic_end();
+
+	return ret;
+}
+
+static int __init kcsan_selftest(void)
+{
+	int passed = 0;
+	int total = 0;
+
+#define RUN_TEST(do_test)                                                      \
+	do {                                                                   \
+		++total;                                                       \
+		if (do_test())                                                 \
+			++passed;                                              \
+		else                                                           \
+			pr_err("selftest: " #do_test " failed");               \
+	} while (0)
+
+	RUN_TEST(test_requires);
+	RUN_TEST(test_encode_decode);
+	RUN_TEST(test_matching_access);
+	RUN_TEST(test_barrier);
+
+	pr_info("selftest: %d/%d tests passed\n", passed, total);
+	if (passed != total)
+		panic("selftests failed");
+	return 0;
+}
+postcore_initcall(kcsan_selftest);
diff --git a/kernel/kexec.c b/kernel/kexec.c
new file mode 100644
index 000000000..5ff1dcc4a
--- /dev/null
+++ b/kernel/kexec.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kexec.c - kexec_load system call
+ * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/capability.h>
+#include <linux/mm.h>
+#include <linux/file.h>
+#include <linux/security.h>
+#include <linux/kexec.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/syscalls.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+
+#include "kexec_internal.h"
+
+static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
+			     unsigned long nr_segments,
+			     struct kexec_segment *segments,
+			     unsigned long flags)
+{
+	int ret;
+	struct kimage *image;
+	bool kexec_on_panic = flags & KEXEC_ON_CRASH;
+
+	if (kexec_on_panic) {
+		/* Verify we have a valid entry point */
+		if ((entry < phys_to_boot_phys(crashk_res.start)) ||
+		    (entry > phys_to_boot_phys(crashk_res.end)))
+			return -EADDRNOTAVAIL;
+	}
+
+	/* Allocate and initialize a controlling structure */
+	image = do_kimage_alloc_init();
+	if (!image)
+		return -ENOMEM;
+
+	image->start = entry;
+	image->nr_segments = nr_segments;
+	memcpy(image->segment, segments, nr_segments * sizeof(*segments));
+
+	if (kexec_on_panic) {
+		/* Enable special crash kernel control page alloc policy. */
+		image->control_page = crashk_res.start;
+		image->type = KEXEC_TYPE_CRASH;
+	}
+
+	ret = sanity_check_segment_list(image);
+	if (ret)
+		goto out_free_image;
+
+	/*
+	 * Find a location for the control code buffer, and add it
+	 * the vector of segments so that it's pages will also be
+	 * counted as destination pages.
+	 */
+	ret = -ENOMEM;
+	image->control_code_page = kimage_alloc_control_pages(image,
+					   get_order(KEXEC_CONTROL_PAGE_SIZE));
+	if (!image->control_code_page) {
+		pr_err("Could not allocate control_code_buffer\n");
+		goto out_free_image;
+	}
+
+	if (!kexec_on_panic) {
+		image->swap_page = kimage_alloc_control_pages(image, 0);
+		if (!image->swap_page) {
+			pr_err("Could not allocate swap buffer\n");
+			goto out_free_control_pages;
+		}
+	}
+
+	*rimage = image;
+	return 0;
+out_free_control_pages:
+	kimage_free_page_list(&image->control_pages);
+out_free_image:
+	kfree(image);
+	return ret;
+}
+
+static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
+		struct kexec_segment *segments, unsigned long flags)
+{
+	struct kimage **dest_image, *image;
+	unsigned long i;
+	int ret;
+
+	/*
+	 * Because we write directly to the reserved memory region when loading
+	 * crash kernels we need a serialization here to prevent multiple crash
+	 * kernels from attempting to load simultaneously.
+	 */
+	if (!kexec_trylock())
+		return -EBUSY;
+
+	if (flags & KEXEC_ON_CRASH) {
+		dest_image = &kexec_crash_image;
+		if (kexec_crash_image)
+			arch_kexec_unprotect_crashkres();
+	} else {
+		dest_image = &kexec_image;
+	}
+
+	if (nr_segments == 0) {
+		/* Uninstall image */
+		kimage_free(xchg(dest_image, NULL));
+		ret = 0;
+		goto out_unlock;
+	}
+	if (flags & KEXEC_ON_CRASH) {
+		/*
+		 * Loading another kernel to switch to if this one
+		 * crashes.  Free any current crash dump kernel before
+		 * we corrupt it.
+		 */
+		kimage_free(xchg(&kexec_crash_image, NULL));
+	}
+
+	ret = kimage_alloc_init(&image, entry, nr_segments, segments, flags);
+	if (ret)
+		goto out_unlock;
+
+	if (flags & KEXEC_PRESERVE_CONTEXT)
+		image->preserve_context = 1;
+
+	ret = machine_kexec_prepare(image);
+	if (ret)
+		goto out;
+
+	/*
+	 * Some architecture(like S390) may touch the crash memory before
+	 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
+	 */
+	ret = kimage_crash_copy_vmcoreinfo(image);
+	if (ret)
+		goto out;
+
+	for (i = 0; i < nr_segments; i++) {
+		ret = kimage_load_segment(image, &image->segment[i]);
+		if (ret)
+			goto out;
+	}
+
+	kimage_terminate(image);
+
+	ret = machine_kexec_post_load(image);
+	if (ret)
+		goto out;
+
+	/* Install the new kernel and uninstall the old */
+	image = xchg(dest_image, image);
+
+out:
+	if ((flags & KEXEC_ON_CRASH) && kexec_crash_image)
+		arch_kexec_protect_crashkres();
+
+	kimage_free(image);
+out_unlock:
+	kexec_unlock();
+	return ret;
+}
+
+/*
+ * Exec Kernel system call: for obvious reasons only root may call it.
+ *
+ * This call breaks up into three pieces.
+ * - A generic part which loads the new kernel from the current
+ *   address space, and very carefully places the data in the
+ *   allocated pages.
+ *
+ * - A generic part that interacts with the kernel and tells all of
+ *   the devices to shut down.  Preventing on-going dmas, and placing
+ *   the devices in a consistent state so a later kernel can
+ *   reinitialize them.
+ *
+ * - A machine specific part that includes the syscall number
+ *   and then copies the image to it's final destination.  And
+ *   jumps into the image at entry.
+ *
+ * kexec does not sync, or unmount filesystems so if you need
+ * that to happen you need to do that yourself.
+ */
+
+static inline int kexec_load_check(unsigned long nr_segments,
+				   unsigned long flags)
+{
+	int result;
+
+	/* We only trust the superuser with rebooting the system. */
+	if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
+		return -EPERM;
+
+	/* Permit LSMs and IMA to fail the kexec */
+	result = security_kernel_load_data(LOADING_KEXEC_IMAGE, false);
+	if (result < 0)
+		return result;
+
+	/*
+	 * kexec can be used to circumvent module loading restrictions, so
+	 * prevent loading in that case
+	 */
+	result = security_locked_down(LOCKDOWN_KEXEC);
+	if (result)
+		return result;
+
+	/*
+	 * Verify we have a legal set of flags
+	 * This leaves us room for future extensions.
+	 */
+	if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
+		return -EINVAL;
+
+	/* Put an artificial cap on the number
+	 * of segments passed to kexec_load.
+	 */
+	if (nr_segments > KEXEC_SEGMENT_MAX)
+		return -EINVAL;
+
+	return 0;
+}
+
+SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
+		struct kexec_segment __user *, segments, unsigned long, flags)
+{
+	struct kexec_segment *ksegments;
+	unsigned long result;
+
+	result = kexec_load_check(nr_segments, flags);
+	if (result)
+		return result;
+
+	/* Verify we are on the appropriate architecture */
+	if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
+		((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
+		return -EINVAL;
+
+	ksegments = memdup_array_user(segments, nr_segments, sizeof(ksegments[0]));
+	if (IS_ERR(ksegments))
+		return PTR_ERR(ksegments);
+
+	result = do_kexec_load(entry, nr_segments, ksegments, flags);
+	kfree(ksegments);
+
+	return result;
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE4(kexec_load, compat_ulong_t, entry,
+		       compat_ulong_t, nr_segments,
+		       struct compat_kexec_segment __user *, segments,
+		       compat_ulong_t, flags)
+{
+	struct compat_kexec_segment in;
+	struct kexec_segment *ksegments;
+	unsigned long i, result;
+
+	result = kexec_load_check(nr_segments, flags);
+	if (result)
+		return result;
+
+	/* Don't allow clients that don't understand the native
+	 * architecture to do anything.
+	 */
+	if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
+		return -EINVAL;
+
+	ksegments = kmalloc_array(nr_segments, sizeof(ksegments[0]),
+			GFP_KERNEL);
+	if (!ksegments)
+		return -ENOMEM;
+
+	for (i = 0; i < nr_segments; i++) {
+		result = copy_from_user(&in, &segments[i], sizeof(in));
+		if (result)
+			goto fail;
+
+		ksegments[i].buf   = compat_ptr(in.buf);
+		ksegments[i].bufsz = in.bufsz;
+		ksegments[i].mem   = in.mem;
+		ksegments[i].memsz = in.memsz;
+	}
+
+	result = do_kexec_load(entry, nr_segments, ksegments, flags);
+
+fail:
+	kfree(ksegments);
+	return result;
+}
+#endif
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
new file mode 100644
index 000000000..79c012fbb
--- /dev/null
+++ b/kernel/kexec_core.c
@@ -0,0 +1,1216 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kexec.c - kexec system call core code.
+ * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/capability.h>
+#include <linux/mm.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/kexec.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/highmem.h>
+#include <linux/syscalls.h>
+#include <linux/reboot.h>
+#include <linux/ioport.h>
+#include <linux/hardirq.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/utsname.h>
+#include <linux/numa.h>
+#include <linux/suspend.h>
+#include <linux/device.h>
+#include <linux/freezer.h>
+#include <linux/panic_notifier.h>
+#include <linux/pm.h>
+#include <linux/cpu.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/console.h>
+#include <linux/vmalloc.h>
+#include <linux/swap.h>
+#include <linux/syscore_ops.h>
+#include <linux/compiler.h>
+#include <linux/hugetlb.h>
+#include <linux/objtool.h>
+#include <linux/kmsg_dump.h>
+
+#include <asm/page.h>
+#include <asm/sections.h>
+
+#include <crypto/hash.h>
+#include "kexec_internal.h"
+
+atomic_t __kexec_lock = ATOMIC_INIT(0);
+
+/* Per cpu memory for storing cpu states in case of system crash. */
+note_buf_t __percpu *crash_notes;
+
+/* Flag to indicate we are going to kexec a new kernel */
+bool kexec_in_progress = false;
+
+
+/* Location of the reserved area for the crash kernel */
+struct resource crashk_res = {
+	.name  = "Crash kernel",
+	.start = 0,
+	.end   = 0,
+	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
+	.desc  = IORES_DESC_CRASH_KERNEL
+};
+struct resource crashk_low_res = {
+	.name  = "Crash kernel",
+	.start = 0,
+	.end   = 0,
+	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
+	.desc  = IORES_DESC_CRASH_KERNEL
+};
+
+int kexec_should_crash(struct task_struct *p)
+{
+	/*
+	 * If crash_kexec_post_notifiers is enabled, don't run
+	 * crash_kexec() here yet, which must be run after panic
+	 * notifiers in panic().
+	 */
+	if (crash_kexec_post_notifiers)
+		return 0;
+	/*
+	 * There are 4 panic() calls in make_task_dead() path, each of which
+	 * corresponds to each of these 4 conditions.
+	 */
+	if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
+		return 1;
+	return 0;
+}
+
+int kexec_crash_loaded(void)
+{
+	return !!kexec_crash_image;
+}
+EXPORT_SYMBOL_GPL(kexec_crash_loaded);
+
+/*
+ * When kexec transitions to the new kernel there is a one-to-one
+ * mapping between physical and virtual addresses.  On processors
+ * where you can disable the MMU this is trivial, and easy.  For
+ * others it is still a simple predictable page table to setup.
+ *
+ * In that environment kexec copies the new kernel to its final
+ * resting place.  This means I can only support memory whose
+ * physical address can fit in an unsigned long.  In particular
+ * addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
+ * If the assembly stub has more restrictive requirements
+ * KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
+ * defined more restrictively in <asm/kexec.h>.
+ *
+ * The code for the transition from the current kernel to the
+ * new kernel is placed in the control_code_buffer, whose size
+ * is given by KEXEC_CONTROL_PAGE_SIZE.  In the best case only a single
+ * page of memory is necessary, but some architectures require more.
+ * Because this memory must be identity mapped in the transition from
+ * virtual to physical addresses it must live in the range
+ * 0 - TASK_SIZE, as only the user space mappings are arbitrarily
+ * modifiable.
+ *
+ * The assembly stub in the control code buffer is passed a linked list
+ * of descriptor pages detailing the source pages of the new kernel,
+ * and the destination addresses of those source pages.  As this data
+ * structure is not used in the context of the current OS, it must
+ * be self-contained.
+ *
+ * The code has been made to work with highmem pages and will use a
+ * destination page in its final resting place (if it happens
+ * to allocate it).  The end product of this is that most of the
+ * physical address space, and most of RAM can be used.
+ *
+ * Future directions include:
+ *  - allocating a page table with the control code buffer identity
+ *    mapped, to simplify machine_kexec and make kexec_on_panic more
+ *    reliable.
+ */
+
+/*
+ * KIMAGE_NO_DEST is an impossible destination address..., for
+ * allocating pages whose destination address we do not care about.
+ */
+#define KIMAGE_NO_DEST (-1UL)
+#define PAGE_COUNT(x) (((x) + PAGE_SIZE - 1) >> PAGE_SHIFT)
+
+static struct page *kimage_alloc_page(struct kimage *image,
+				       gfp_t gfp_mask,
+				       unsigned long dest);
+
+int sanity_check_segment_list(struct kimage *image)
+{
+	int i;
+	unsigned long nr_segments = image->nr_segments;
+	unsigned long total_pages = 0;
+	unsigned long nr_pages = totalram_pages();
+
+	/*
+	 * Verify we have good destination addresses.  The caller is
+	 * responsible for making certain we don't attempt to load
+	 * the new image into invalid or reserved areas of RAM.  This
+	 * just verifies it is an address we can use.
+	 *
+	 * Since the kernel does everything in page size chunks ensure
+	 * the destination addresses are page aligned.  Too many
+	 * special cases crop of when we don't do this.  The most
+	 * insidious is getting overlapping destination addresses
+	 * simply because addresses are changed to page size
+	 * granularity.
+	 */
+	for (i = 0; i < nr_segments; i++) {
+		unsigned long mstart, mend;
+
+		mstart = image->segment[i].mem;
+		mend   = mstart + image->segment[i].memsz;
+		if (mstart > mend)
+			return -EADDRNOTAVAIL;
+		if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
+			return -EADDRNOTAVAIL;
+		if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
+			return -EADDRNOTAVAIL;
+	}
+
+	/* Verify our destination addresses do not overlap.
+	 * If we alloed overlapping destination addresses
+	 * through very weird things can happen with no
+	 * easy explanation as one segment stops on another.
+	 */
+	for (i = 0; i < nr_segments; i++) {
+		unsigned long mstart, mend;
+		unsigned long j;
+
+		mstart = image->segment[i].mem;
+		mend   = mstart + image->segment[i].memsz;
+		for (j = 0; j < i; j++) {
+			unsigned long pstart, pend;
+
+			pstart = image->segment[j].mem;
+			pend   = pstart + image->segment[j].memsz;
+			/* Do the segments overlap ? */
+			if ((mend > pstart) && (mstart < pend))
+				return -EINVAL;
+		}
+	}
+
+	/* Ensure our buffer sizes are strictly less than
+	 * our memory sizes.  This should always be the case,
+	 * and it is easier to check up front than to be surprised
+	 * later on.
+	 */
+	for (i = 0; i < nr_segments; i++) {
+		if (image->segment[i].bufsz > image->segment[i].memsz)
+			return -EINVAL;
+	}
+
+	/*
+	 * Verify that no more than half of memory will be consumed. If the
+	 * request from userspace is too large, a large amount of time will be
+	 * wasted allocating pages, which can cause a soft lockup.
+	 */
+	for (i = 0; i < nr_segments; i++) {
+		if (PAGE_COUNT(image->segment[i].memsz) > nr_pages / 2)
+			return -EINVAL;
+
+		total_pages += PAGE_COUNT(image->segment[i].memsz);
+	}
+
+	if (total_pages > nr_pages / 2)
+		return -EINVAL;
+
+	/*
+	 * Verify we have good destination addresses.  Normally
+	 * the caller is responsible for making certain we don't
+	 * attempt to load the new image into invalid or reserved
+	 * areas of RAM.  But crash kernels are preloaded into a
+	 * reserved area of ram.  We must ensure the addresses
+	 * are in the reserved area otherwise preloading the
+	 * kernel could corrupt things.
+	 */
+
+	if (image->type == KEXEC_TYPE_CRASH) {
+		for (i = 0; i < nr_segments; i++) {
+			unsigned long mstart, mend;
+
+			mstart = image->segment[i].mem;
+			mend = mstart + image->segment[i].memsz - 1;
+			/* Ensure we are within the crash kernel limits */
+			if ((mstart < phys_to_boot_phys(crashk_res.start)) ||
+			    (mend > phys_to_boot_phys(crashk_res.end)))
+				return -EADDRNOTAVAIL;
+		}
+	}
+
+	return 0;
+}
+
+struct kimage *do_kimage_alloc_init(void)
+{
+	struct kimage *image;
+
+	/* Allocate a controlling structure */
+	image = kzalloc(sizeof(*image), GFP_KERNEL);
+	if (!image)
+		return NULL;
+
+	image->head = 0;
+	image->entry = &image->head;
+	image->last_entry = &image->head;
+	image->control_page = ~0; /* By default this does not apply */
+	image->type = KEXEC_TYPE_DEFAULT;
+
+	/* Initialize the list of control pages */
+	INIT_LIST_HEAD(&image->control_pages);
+
+	/* Initialize the list of destination pages */
+	INIT_LIST_HEAD(&image->dest_pages);
+
+	/* Initialize the list of unusable pages */
+	INIT_LIST_HEAD(&image->unusable_pages);
+
+	return image;
+}
+
+int kimage_is_destination_range(struct kimage *image,
+					unsigned long start,
+					unsigned long end)
+{
+	unsigned long i;
+
+	for (i = 0; i < image->nr_segments; i++) {
+		unsigned long mstart, mend;
+
+		mstart = image->segment[i].mem;
+		mend = mstart + image->segment[i].memsz;
+		if ((end > mstart) && (start < mend))
+			return 1;
+	}
+
+	return 0;
+}
+
+static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
+{
+	struct page *pages;
+
+	if (fatal_signal_pending(current))
+		return NULL;
+	pages = alloc_pages(gfp_mask & ~__GFP_ZERO, order);
+	if (pages) {
+		unsigned int count, i;
+
+		pages->mapping = NULL;
+		set_page_private(pages, order);
+		count = 1 << order;
+		for (i = 0; i < count; i++)
+			SetPageReserved(pages + i);
+
+		arch_kexec_post_alloc_pages(page_address(pages), count,
+					    gfp_mask);
+
+		if (gfp_mask & __GFP_ZERO)
+			for (i = 0; i < count; i++)
+				clear_highpage(pages + i);
+	}
+
+	return pages;
+}
+
+static void kimage_free_pages(struct page *page)
+{
+	unsigned int order, count, i;
+
+	order = page_private(page);
+	count = 1 << order;
+
+	arch_kexec_pre_free_pages(page_address(page), count);
+
+	for (i = 0; i < count; i++)
+		ClearPageReserved(page + i);
+	__free_pages(page, order);
+}
+
+void kimage_free_page_list(struct list_head *list)
+{
+	struct page *page, *next;
+
+	list_for_each_entry_safe(page, next, list, lru) {
+		list_del(&page->lru);
+		kimage_free_pages(page);
+	}
+}
+
+static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
+							unsigned int order)
+{
+	/* Control pages are special, they are the intermediaries
+	 * that are needed while we copy the rest of the pages
+	 * to their final resting place.  As such they must
+	 * not conflict with either the destination addresses
+	 * or memory the kernel is already using.
+	 *
+	 * The only case where we really need more than one of
+	 * these are for architectures where we cannot disable
+	 * the MMU and must instead generate an identity mapped
+	 * page table for all of the memory.
+	 *
+	 * At worst this runs in O(N) of the image size.
+	 */
+	struct list_head extra_pages;
+	struct page *pages;
+	unsigned int count;
+
+	count = 1 << order;
+	INIT_LIST_HEAD(&extra_pages);
+
+	/* Loop while I can allocate a page and the page allocated
+	 * is a destination page.
+	 */
+	do {
+		unsigned long pfn, epfn, addr, eaddr;
+
+		pages = kimage_alloc_pages(KEXEC_CONTROL_MEMORY_GFP, order);
+		if (!pages)
+			break;
+		pfn   = page_to_boot_pfn(pages);
+		epfn  = pfn + count;
+		addr  = pfn << PAGE_SHIFT;
+		eaddr = epfn << PAGE_SHIFT;
+		if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
+			      kimage_is_destination_range(image, addr, eaddr)) {
+			list_add(&pages->lru, &extra_pages);
+			pages = NULL;
+		}
+	} while (!pages);
+
+	if (pages) {
+		/* Remember the allocated page... */
+		list_add(&pages->lru, &image->control_pages);
+
+		/* Because the page is already in it's destination
+		 * location we will never allocate another page at
+		 * that address.  Therefore kimage_alloc_pages
+		 * will not return it (again) and we don't need
+		 * to give it an entry in image->segment[].
+		 */
+	}
+	/* Deal with the destination pages I have inadvertently allocated.
+	 *
+	 * Ideally I would convert multi-page allocations into single
+	 * page allocations, and add everything to image->dest_pages.
+	 *
+	 * For now it is simpler to just free the pages.
+	 */
+	kimage_free_page_list(&extra_pages);
+
+	return pages;
+}
+
+static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
+						      unsigned int order)
+{
+	/* Control pages are special, they are the intermediaries
+	 * that are needed while we copy the rest of the pages
+	 * to their final resting place.  As such they must
+	 * not conflict with either the destination addresses
+	 * or memory the kernel is already using.
+	 *
+	 * Control pages are also the only pags we must allocate
+	 * when loading a crash kernel.  All of the other pages
+	 * are specified by the segments and we just memcpy
+	 * into them directly.
+	 *
+	 * The only case where we really need more than one of
+	 * these are for architectures where we cannot disable
+	 * the MMU and must instead generate an identity mapped
+	 * page table for all of the memory.
+	 *
+	 * Given the low demand this implements a very simple
+	 * allocator that finds the first hole of the appropriate
+	 * size in the reserved memory region, and allocates all
+	 * of the memory up to and including the hole.
+	 */
+	unsigned long hole_start, hole_end, size;
+	struct page *pages;
+
+	pages = NULL;
+	size = (1 << order) << PAGE_SHIFT;
+	hole_start = (image->control_page + (size - 1)) & ~(size - 1);
+	hole_end   = hole_start + size - 1;
+	while (hole_end <= crashk_res.end) {
+		unsigned long i;
+
+		cond_resched();
+
+		if (hole_end > KEXEC_CRASH_CONTROL_MEMORY_LIMIT)
+			break;
+		/* See if I overlap any of the segments */
+		for (i = 0; i < image->nr_segments; i++) {
+			unsigned long mstart, mend;
+
+			mstart = image->segment[i].mem;
+			mend   = mstart + image->segment[i].memsz - 1;
+			if ((hole_end >= mstart) && (hole_start <= mend)) {
+				/* Advance the hole to the end of the segment */
+				hole_start = (mend + (size - 1)) & ~(size - 1);
+				hole_end   = hole_start + size - 1;
+				break;
+			}
+		}
+		/* If I don't overlap any segments I have found my hole! */
+		if (i == image->nr_segments) {
+			pages = pfn_to_page(hole_start >> PAGE_SHIFT);
+			image->control_page = hole_end;
+			break;
+		}
+	}
+
+	/* Ensure that these pages are decrypted if SME is enabled. */
+	if (pages)
+		arch_kexec_post_alloc_pages(page_address(pages), 1 << order, 0);
+
+	return pages;
+}
+
+
+struct page *kimage_alloc_control_pages(struct kimage *image,
+					 unsigned int order)
+{
+	struct page *pages = NULL;
+
+	switch (image->type) {
+	case KEXEC_TYPE_DEFAULT:
+		pages = kimage_alloc_normal_control_pages(image, order);
+		break;
+	case KEXEC_TYPE_CRASH:
+		pages = kimage_alloc_crash_control_pages(image, order);
+		break;
+	}
+
+	return pages;
+}
+
+int kimage_crash_copy_vmcoreinfo(struct kimage *image)
+{
+	struct page *vmcoreinfo_page;
+	void *safecopy;
+
+	if (image->type != KEXEC_TYPE_CRASH)
+		return 0;
+
+	/*
+	 * For kdump, allocate one vmcoreinfo safe copy from the
+	 * crash memory. as we have arch_kexec_protect_crashkres()
+	 * after kexec syscall, we naturally protect it from write
+	 * (even read) access under kernel direct mapping. But on
+	 * the other hand, we still need to operate it when crash
+	 * happens to generate vmcoreinfo note, hereby we rely on
+	 * vmap for this purpose.
+	 */
+	vmcoreinfo_page = kimage_alloc_control_pages(image, 0);
+	if (!vmcoreinfo_page) {
+		pr_warn("Could not allocate vmcoreinfo buffer\n");
+		return -ENOMEM;
+	}
+	safecopy = vmap(&vmcoreinfo_page, 1, VM_MAP, PAGE_KERNEL);
+	if (!safecopy) {
+		pr_warn("Could not vmap vmcoreinfo buffer\n");
+		return -ENOMEM;
+	}
+
+	image->vmcoreinfo_data_copy = safecopy;
+	crash_update_vmcoreinfo_safecopy(safecopy);
+
+	return 0;
+}
+
+static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
+{
+	if (*image->entry != 0)
+		image->entry++;
+
+	if (image->entry == image->last_entry) {
+		kimage_entry_t *ind_page;
+		struct page *page;
+
+		page = kimage_alloc_page(image, GFP_KERNEL, KIMAGE_NO_DEST);
+		if (!page)
+			return -ENOMEM;
+
+		ind_page = page_address(page);
+		*image->entry = virt_to_boot_phys(ind_page) | IND_INDIRECTION;
+		image->entry = ind_page;
+		image->last_entry = ind_page +
+				      ((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
+	}
+	*image->entry = entry;
+	image->entry++;
+	*image->entry = 0;
+
+	return 0;
+}
+
+static int kimage_set_destination(struct kimage *image,
+				   unsigned long destination)
+{
+	int result;
+
+	destination &= PAGE_MASK;
+	result = kimage_add_entry(image, destination | IND_DESTINATION);
+
+	return result;
+}
+
+
+static int kimage_add_page(struct kimage *image, unsigned long page)
+{
+	int result;
+
+	page &= PAGE_MASK;
+	result = kimage_add_entry(image, page | IND_SOURCE);
+
+	return result;
+}
+
+
+static void kimage_free_extra_pages(struct kimage *image)
+{
+	/* Walk through and free any extra destination pages I may have */
+	kimage_free_page_list(&image->dest_pages);
+
+	/* Walk through and free any unusable pages I have cached */
+	kimage_free_page_list(&image->unusable_pages);
+
+}
+
+void kimage_terminate(struct kimage *image)
+{
+	if (*image->entry != 0)
+		image->entry++;
+
+	*image->entry = IND_DONE;
+}
+
+#define for_each_kimage_entry(image, ptr, entry) \
+	for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
+		ptr = (entry & IND_INDIRECTION) ? \
+			boot_phys_to_virt((entry & PAGE_MASK)) : ptr + 1)
+
+static void kimage_free_entry(kimage_entry_t entry)
+{
+	struct page *page;
+
+	page = boot_pfn_to_page(entry >> PAGE_SHIFT);
+	kimage_free_pages(page);
+}
+
+void kimage_free(struct kimage *image)
+{
+	kimage_entry_t *ptr, entry;
+	kimage_entry_t ind = 0;
+
+	if (!image)
+		return;
+
+	if (image->vmcoreinfo_data_copy) {
+		crash_update_vmcoreinfo_safecopy(NULL);
+		vunmap(image->vmcoreinfo_data_copy);
+	}
+
+	kimage_free_extra_pages(image);
+	for_each_kimage_entry(image, ptr, entry) {
+		if (entry & IND_INDIRECTION) {
+			/* Free the previous indirection page */
+			if (ind & IND_INDIRECTION)
+				kimage_free_entry(ind);
+			/* Save this indirection page until we are
+			 * done with it.
+			 */
+			ind = entry;
+		} else if (entry & IND_SOURCE)
+			kimage_free_entry(entry);
+	}
+	/* Free the final indirection page */
+	if (ind & IND_INDIRECTION)
+		kimage_free_entry(ind);
+
+	/* Handle any machine specific cleanup */
+	machine_kexec_cleanup(image);
+
+	/* Free the kexec control pages... */
+	kimage_free_page_list(&image->control_pages);
+
+	/*
+	 * Free up any temporary buffers allocated. This might hit if
+	 * error occurred much later after buffer allocation.
+	 */
+	if (image->file_mode)
+		kimage_file_post_load_cleanup(image);
+
+	kfree(image);
+}
+
+static kimage_entry_t *kimage_dst_used(struct kimage *image,
+					unsigned long page)
+{
+	kimage_entry_t *ptr, entry;
+	unsigned long destination = 0;
+
+	for_each_kimage_entry(image, ptr, entry) {
+		if (entry & IND_DESTINATION)
+			destination = entry & PAGE_MASK;
+		else if (entry & IND_SOURCE) {
+			if (page == destination)
+				return ptr;
+			destination += PAGE_SIZE;
+		}
+	}
+
+	return NULL;
+}
+
+static struct page *kimage_alloc_page(struct kimage *image,
+					gfp_t gfp_mask,
+					unsigned long destination)
+{
+	/*
+	 * Here we implement safeguards to ensure that a source page
+	 * is not copied to its destination page before the data on
+	 * the destination page is no longer useful.
+	 *
+	 * To do this we maintain the invariant that a source page is
+	 * either its own destination page, or it is not a
+	 * destination page at all.
+	 *
+	 * That is slightly stronger than required, but the proof
+	 * that no problems will not occur is trivial, and the
+	 * implementation is simply to verify.
+	 *
+	 * When allocating all pages normally this algorithm will run
+	 * in O(N) time, but in the worst case it will run in O(N^2)
+	 * time.   If the runtime is a problem the data structures can
+	 * be fixed.
+	 */
+	struct page *page;
+	unsigned long addr;
+
+	/*
+	 * Walk through the list of destination pages, and see if I
+	 * have a match.
+	 */
+	list_for_each_entry(page, &image->dest_pages, lru) {
+		addr = page_to_boot_pfn(page) << PAGE_SHIFT;
+		if (addr == destination) {
+			list_del(&page->lru);
+			return page;
+		}
+	}
+	page = NULL;
+	while (1) {
+		kimage_entry_t *old;
+
+		/* Allocate a page, if we run out of memory give up */
+		page = kimage_alloc_pages(gfp_mask, 0);
+		if (!page)
+			return NULL;
+		/* If the page cannot be used file it away */
+		if (page_to_boot_pfn(page) >
+				(KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
+			list_add(&page->lru, &image->unusable_pages);
+			continue;
+		}
+		addr = page_to_boot_pfn(page) << PAGE_SHIFT;
+
+		/* If it is the destination page we want use it */
+		if (addr == destination)
+			break;
+
+		/* If the page is not a destination page use it */
+		if (!kimage_is_destination_range(image, addr,
+						  addr + PAGE_SIZE))
+			break;
+
+		/*
+		 * I know that the page is someones destination page.
+		 * See if there is already a source page for this
+		 * destination page.  And if so swap the source pages.
+		 */
+		old = kimage_dst_used(image, addr);
+		if (old) {
+			/* If so move it */
+			unsigned long old_addr;
+			struct page *old_page;
+
+			old_addr = *old & PAGE_MASK;
+			old_page = boot_pfn_to_page(old_addr >> PAGE_SHIFT);
+			copy_highpage(page, old_page);
+			*old = addr | (*old & ~PAGE_MASK);
+
+			/* The old page I have found cannot be a
+			 * destination page, so return it if it's
+			 * gfp_flags honor the ones passed in.
+			 */
+			if (!(gfp_mask & __GFP_HIGHMEM) &&
+			    PageHighMem(old_page)) {
+				kimage_free_pages(old_page);
+				continue;
+			}
+			page = old_page;
+			break;
+		}
+		/* Place the page on the destination list, to be used later */
+		list_add(&page->lru, &image->dest_pages);
+	}
+
+	return page;
+}
+
+static int kimage_load_normal_segment(struct kimage *image,
+					 struct kexec_segment *segment)
+{
+	unsigned long maddr;
+	size_t ubytes, mbytes;
+	int result;
+	unsigned char __user *buf = NULL;
+	unsigned char *kbuf = NULL;
+
+	if (image->file_mode)
+		kbuf = segment->kbuf;
+	else
+		buf = segment->buf;
+	ubytes = segment->bufsz;
+	mbytes = segment->memsz;
+	maddr = segment->mem;
+
+	result = kimage_set_destination(image, maddr);
+	if (result < 0)
+		goto out;
+
+	while (mbytes) {
+		struct page *page;
+		char *ptr;
+		size_t uchunk, mchunk;
+
+		page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
+		if (!page) {
+			result  = -ENOMEM;
+			goto out;
+		}
+		result = kimage_add_page(image, page_to_boot_pfn(page)
+								<< PAGE_SHIFT);
+		if (result < 0)
+			goto out;
+
+		ptr = kmap_local_page(page);
+		/* Start with a clear page */
+		clear_page(ptr);
+		ptr += maddr & ~PAGE_MASK;
+		mchunk = min_t(size_t, mbytes,
+				PAGE_SIZE - (maddr & ~PAGE_MASK));
+		uchunk = min(ubytes, mchunk);
+
+		/* For file based kexec, source pages are in kernel memory */
+		if (image->file_mode)
+			memcpy(ptr, kbuf, uchunk);
+		else
+			result = copy_from_user(ptr, buf, uchunk);
+		kunmap_local(ptr);
+		if (result) {
+			result = -EFAULT;
+			goto out;
+		}
+		ubytes -= uchunk;
+		maddr  += mchunk;
+		if (image->file_mode)
+			kbuf += mchunk;
+		else
+			buf += mchunk;
+		mbytes -= mchunk;
+
+		cond_resched();
+	}
+out:
+	return result;
+}
+
+static int kimage_load_crash_segment(struct kimage *image,
+					struct kexec_segment *segment)
+{
+	/* For crash dumps kernels we simply copy the data from
+	 * user space to it's destination.
+	 * We do things a page at a time for the sake of kmap.
+	 */
+	unsigned long maddr;
+	size_t ubytes, mbytes;
+	int result;
+	unsigned char __user *buf = NULL;
+	unsigned char *kbuf = NULL;
+
+	result = 0;
+	if (image->file_mode)
+		kbuf = segment->kbuf;
+	else
+		buf = segment->buf;
+	ubytes = segment->bufsz;
+	mbytes = segment->memsz;
+	maddr = segment->mem;
+	while (mbytes) {
+		struct page *page;
+		char *ptr;
+		size_t uchunk, mchunk;
+
+		page = boot_pfn_to_page(maddr >> PAGE_SHIFT);
+		if (!page) {
+			result  = -ENOMEM;
+			goto out;
+		}
+		arch_kexec_post_alloc_pages(page_address(page), 1, 0);
+		ptr = kmap_local_page(page);
+		ptr += maddr & ~PAGE_MASK;
+		mchunk = min_t(size_t, mbytes,
+				PAGE_SIZE - (maddr & ~PAGE_MASK));
+		uchunk = min(ubytes, mchunk);
+		if (mchunk > uchunk) {
+			/* Zero the trailing part of the page */
+			memset(ptr + uchunk, 0, mchunk - uchunk);
+		}
+
+		/* For file based kexec, source pages are in kernel memory */
+		if (image->file_mode)
+			memcpy(ptr, kbuf, uchunk);
+		else
+			result = copy_from_user(ptr, buf, uchunk);
+		kexec_flush_icache_page(page);
+		kunmap_local(ptr);
+		arch_kexec_pre_free_pages(page_address(page), 1);
+		if (result) {
+			result = -EFAULT;
+			goto out;
+		}
+		ubytes -= uchunk;
+		maddr  += mchunk;
+		if (image->file_mode)
+			kbuf += mchunk;
+		else
+			buf += mchunk;
+		mbytes -= mchunk;
+
+		cond_resched();
+	}
+out:
+	return result;
+}
+
+int kimage_load_segment(struct kimage *image,
+				struct kexec_segment *segment)
+{
+	int result = -ENOMEM;
+
+	switch (image->type) {
+	case KEXEC_TYPE_DEFAULT:
+		result = kimage_load_normal_segment(image, segment);
+		break;
+	case KEXEC_TYPE_CRASH:
+		result = kimage_load_crash_segment(image, segment);
+		break;
+	}
+
+	return result;
+}
+
+struct kimage *kexec_image;
+struct kimage *kexec_crash_image;
+int kexec_load_disabled;
+#ifdef CONFIG_SYSCTL
+static struct ctl_table kexec_core_sysctls[] = {
+	{
+		.procname	= "kexec_load_disabled",
+		.data		= &kexec_load_disabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		/* only handle a transition from default "0" to "1" */
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_ONE,
+	},
+	{ }
+};
+
+static int __init kexec_core_sysctl_init(void)
+{
+	register_sysctl_init("kernel", kexec_core_sysctls);
+	return 0;
+}
+late_initcall(kexec_core_sysctl_init);
+#endif
+
+/*
+ * No panic_cpu check version of crash_kexec().  This function is called
+ * only when panic_cpu holds the current CPU number; this is the only CPU
+ * which processes crash_kexec routines.
+ */
+void __noclone __crash_kexec(struct pt_regs *regs)
+{
+	/* Take the kexec_lock here to prevent sys_kexec_load
+	 * running on one cpu from replacing the crash kernel
+	 * we are using after a panic on a different cpu.
+	 *
+	 * If the crash kernel was not located in a fixed area
+	 * of memory the xchg(&kexec_crash_image) would be
+	 * sufficient.  But since I reuse the memory...
+	 */
+	if (kexec_trylock()) {
+		if (kexec_crash_image) {
+			struct pt_regs fixed_regs;
+
+			crash_setup_regs(&fixed_regs, regs);
+			crash_save_vmcoreinfo();
+			machine_crash_shutdown(&fixed_regs);
+			machine_kexec(kexec_crash_image);
+		}
+		kexec_unlock();
+	}
+}
+STACK_FRAME_NON_STANDARD(__crash_kexec);
+
+void crash_kexec(struct pt_regs *regs)
+{
+	int old_cpu, this_cpu;
+
+	/*
+	 * Only one CPU is allowed to execute the crash_kexec() code as with
+	 * panic().  Otherwise parallel calls of panic() and crash_kexec()
+	 * may stop each other.  To exclude them, we use panic_cpu here too.
+	 */
+	this_cpu = raw_smp_processor_id();
+	old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
+	if (old_cpu == PANIC_CPU_INVALID) {
+		/* This is the 1st CPU which comes here, so go ahead. */
+		__crash_kexec(regs);
+
+		/*
+		 * Reset panic_cpu to allow another panic()/crash_kexec()
+		 * call.
+		 */
+		atomic_set(&panic_cpu, PANIC_CPU_INVALID);
+	}
+}
+
+ssize_t crash_get_memory_size(void)
+{
+	ssize_t size = 0;
+
+	if (!kexec_trylock())
+		return -EBUSY;
+
+	if (crashk_res.end != crashk_res.start)
+		size = resource_size(&crashk_res);
+
+	kexec_unlock();
+	return size;
+}
+
+int crash_shrink_memory(unsigned long new_size)
+{
+	int ret = 0;
+	unsigned long start, end;
+	unsigned long old_size;
+	struct resource *ram_res;
+
+	if (!kexec_trylock())
+		return -EBUSY;
+
+	if (kexec_crash_image) {
+		ret = -ENOENT;
+		goto unlock;
+	}
+	start = crashk_res.start;
+	end = crashk_res.end;
+	old_size = (end == 0) ? 0 : end - start + 1;
+	new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN);
+	if (new_size >= old_size) {
+		ret = (new_size == old_size) ? 0 : -EINVAL;
+		goto unlock;
+	}
+
+	ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
+	if (!ram_res) {
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	end = start + new_size;
+	crash_free_reserved_phys_range(end, crashk_res.end);
+
+	if ((start == end) && (crashk_res.parent != NULL))
+		release_resource(&crashk_res);
+
+	ram_res->start = end;
+	ram_res->end = crashk_res.end;
+	ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
+	ram_res->name = "System RAM";
+
+	crashk_res.end = end - 1;
+
+	insert_resource(&iomem_resource, ram_res);
+
+unlock:
+	kexec_unlock();
+	return ret;
+}
+
+void crash_save_cpu(struct pt_regs *regs, int cpu)
+{
+	struct elf_prstatus prstatus;
+	u32 *buf;
+
+	if ((cpu < 0) || (cpu >= nr_cpu_ids))
+		return;
+
+	/* Using ELF notes here is opportunistic.
+	 * I need a well defined structure format
+	 * for the data I pass, and I need tags
+	 * on the data to indicate what information I have
+	 * squirrelled away.  ELF notes happen to provide
+	 * all of that, so there is no need to invent something new.
+	 */
+	buf = (u32 *)per_cpu_ptr(crash_notes, cpu);
+	if (!buf)
+		return;
+	memset(&prstatus, 0, sizeof(prstatus));
+	prstatus.common.pr_pid = current->pid;
+	elf_core_copy_regs(&prstatus.pr_reg, regs);
+	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
+			      &prstatus, sizeof(prstatus));
+	final_note(buf);
+}
+
+static int __init crash_notes_memory_init(void)
+{
+	/* Allocate memory for saving cpu registers. */
+	size_t size, align;
+
+	/*
+	 * crash_notes could be allocated across 2 vmalloc pages when percpu
+	 * is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc
+	 * pages are also on 2 continuous physical pages. In this case the
+	 * 2nd part of crash_notes in 2nd page could be lost since only the
+	 * starting address and size of crash_notes are exported through sysfs.
+	 * Here round up the size of crash_notes to the nearest power of two
+	 * and pass it to __alloc_percpu as align value. This can make sure
+	 * crash_notes is allocated inside one physical page.
+	 */
+	size = sizeof(note_buf_t);
+	align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE);
+
+	/*
+	 * Break compile if size is bigger than PAGE_SIZE since crash_notes
+	 * definitely will be in 2 pages with that.
+	 */
+	BUILD_BUG_ON(size > PAGE_SIZE);
+
+	crash_notes = __alloc_percpu(size, align);
+	if (!crash_notes) {
+		pr_warn("Memory allocation for saving cpu register states failed\n");
+		return -ENOMEM;
+	}
+	return 0;
+}
+subsys_initcall(crash_notes_memory_init);
+
+
+/*
+ * Move into place and start executing a preloaded standalone
+ * executable.  If nothing was preloaded return an error.
+ */
+int kernel_kexec(void)
+{
+	int error = 0;
+
+	if (!kexec_trylock())
+		return -EBUSY;
+	if (!kexec_image) {
+		error = -EINVAL;
+		goto Unlock;
+	}
+
+#ifdef CONFIG_KEXEC_JUMP
+	if (kexec_image->preserve_context) {
+		pm_prepare_console();
+		error = freeze_processes();
+		if (error) {
+			error = -EBUSY;
+			goto Restore_console;
+		}
+		suspend_console();
+		error = dpm_suspend_start(PMSG_FREEZE);
+		if (error)
+			goto Resume_console;
+		/* At this point, dpm_suspend_start() has been called,
+		 * but *not* dpm_suspend_end(). We *must* call
+		 * dpm_suspend_end() now.  Otherwise, drivers for
+		 * some devices (e.g. interrupt controllers) become
+		 * desynchronized with the actual state of the
+		 * hardware at resume time, and evil weirdness ensues.
+		 */
+		error = dpm_suspend_end(PMSG_FREEZE);
+		if (error)
+			goto Resume_devices;
+		error = suspend_disable_secondary_cpus();
+		if (error)
+			goto Enable_cpus;
+		local_irq_disable();
+		error = syscore_suspend();
+		if (error)
+			goto Enable_irqs;
+	} else
+#endif
+	{
+		kexec_in_progress = true;
+		kernel_restart_prepare("kexec reboot");
+		migrate_to_reboot_cpu();
+
+		/*
+		 * migrate_to_reboot_cpu() disables CPU hotplug assuming that
+		 * no further code needs to use CPU hotplug (which is true in
+		 * the reboot case). However, the kexec path depends on using
+		 * CPU hotplug again; so re-enable it here.
+		 */
+		cpu_hotplug_enable();
+		pr_notice("Starting new kernel\n");
+		machine_shutdown();
+	}
+
+	kmsg_dump(KMSG_DUMP_SHUTDOWN);
+	machine_kexec(kexec_image);
+
+#ifdef CONFIG_KEXEC_JUMP
+	if (kexec_image->preserve_context) {
+		syscore_resume();
+ Enable_irqs:
+		local_irq_enable();
+ Enable_cpus:
+		suspend_enable_secondary_cpus();
+		dpm_resume_start(PMSG_RESTORE);
+ Resume_devices:
+		dpm_resume_end(PMSG_RESTORE);
+ Resume_console:
+		resume_console();
+		thaw_processes();
+ Restore_console:
+		pm_restore_console();
+	}
+#endif
+
+ Unlock:
+	kexec_unlock();
+	return error;
+}
diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c
new file mode 100644
index 000000000..d3689632e
--- /dev/null
+++ b/kernel/kexec_elf.c
@@ -0,0 +1,430 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Load ELF vmlinux file for the kexec_file_load syscall.
+ *
+ * Copyright (C) 2004  Adam Litke (agl@us.ibm.com)
+ * Copyright (C) 2004  IBM Corp.
+ * Copyright (C) 2005  R Sharada (sharada@in.ibm.com)
+ * Copyright (C) 2006  Mohan Kumar M (mohan@in.ibm.com)
+ * Copyright (C) 2016  IBM Corporation
+ *
+ * Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c.
+ * Heavily modified for the kernel by
+ * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>.
+ */
+
+#define pr_fmt(fmt)	"kexec_elf: " fmt
+
+#include <linux/elf.h>
+#include <linux/kexec.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+static inline bool elf_is_elf_file(const struct elfhdr *ehdr)
+{
+	return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0;
+}
+
+static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value)
+{
+	if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
+		value = le64_to_cpu(value);
+	else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
+		value = be64_to_cpu(value);
+
+	return value;
+}
+
+static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value)
+{
+	if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
+		value = le32_to_cpu(value);
+	else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
+		value = be32_to_cpu(value);
+
+	return value;
+}
+
+static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value)
+{
+	if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
+		value = le16_to_cpu(value);
+	else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
+		value = be16_to_cpu(value);
+
+	return value;
+}
+
+/**
+ * elf_is_ehdr_sane - check that it is safe to use the ELF header
+ * @buf_len:	size of the buffer in which the ELF file is loaded.
+ */
+static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len)
+{
+	if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) {
+		pr_debug("Bad program header size.\n");
+		return false;
+	} else if (ehdr->e_shnum > 0 &&
+		   ehdr->e_shentsize != sizeof(struct elf_shdr)) {
+		pr_debug("Bad section header size.\n");
+		return false;
+	} else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT ||
+		   ehdr->e_version != EV_CURRENT) {
+		pr_debug("Unknown ELF version.\n");
+		return false;
+	}
+
+	if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) {
+		size_t phdr_size;
+
+		/*
+		 * e_phnum is at most 65535 so calculating the size of the
+		 * program header cannot overflow.
+		 */
+		phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum;
+
+		/* Sanity check the program header table location. */
+		if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) {
+			pr_debug("Program headers at invalid location.\n");
+			return false;
+		} else if (ehdr->e_phoff + phdr_size > buf_len) {
+			pr_debug("Program headers truncated.\n");
+			return false;
+		}
+	}
+
+	if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) {
+		size_t shdr_size;
+
+		/*
+		 * e_shnum is at most 65536 so calculating
+		 * the size of the section header cannot overflow.
+		 */
+		shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum;
+
+		/* Sanity check the section header table location. */
+		if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) {
+			pr_debug("Section headers at invalid location.\n");
+			return false;
+		} else if (ehdr->e_shoff + shdr_size > buf_len) {
+			pr_debug("Section headers truncated.\n");
+			return false;
+		}
+	}
+
+	return true;
+}
+
+static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr)
+{
+	struct elfhdr *buf_ehdr;
+
+	if (len < sizeof(*buf_ehdr)) {
+		pr_debug("Buffer is too small to hold ELF header.\n");
+		return -ENOEXEC;
+	}
+
+	memset(ehdr, 0, sizeof(*ehdr));
+	memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident));
+	if (!elf_is_elf_file(ehdr)) {
+		pr_debug("No ELF header magic.\n");
+		return -ENOEXEC;
+	}
+
+	if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) {
+		pr_debug("Not a supported ELF class.\n");
+		return -ENOEXEC;
+	} else  if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB &&
+		ehdr->e_ident[EI_DATA] != ELFDATA2MSB) {
+		pr_debug("Not a supported ELF data format.\n");
+		return -ENOEXEC;
+	}
+
+	buf_ehdr = (struct elfhdr *) buf;
+	if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) {
+		pr_debug("Bad ELF header size.\n");
+		return -ENOEXEC;
+	}
+
+	ehdr->e_type      = elf16_to_cpu(ehdr, buf_ehdr->e_type);
+	ehdr->e_machine   = elf16_to_cpu(ehdr, buf_ehdr->e_machine);
+	ehdr->e_version   = elf32_to_cpu(ehdr, buf_ehdr->e_version);
+	ehdr->e_flags     = elf32_to_cpu(ehdr, buf_ehdr->e_flags);
+	ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize);
+	ehdr->e_phnum     = elf16_to_cpu(ehdr, buf_ehdr->e_phnum);
+	ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize);
+	ehdr->e_shnum     = elf16_to_cpu(ehdr, buf_ehdr->e_shnum);
+	ehdr->e_shstrndx  = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx);
+
+	switch (ehdr->e_ident[EI_CLASS]) {
+	case ELFCLASS64:
+		ehdr->e_entry = elf64_to_cpu(ehdr, buf_ehdr->e_entry);
+		ehdr->e_phoff = elf64_to_cpu(ehdr, buf_ehdr->e_phoff);
+		ehdr->e_shoff = elf64_to_cpu(ehdr, buf_ehdr->e_shoff);
+		break;
+
+	case ELFCLASS32:
+		ehdr->e_entry = elf32_to_cpu(ehdr, buf_ehdr->e_entry);
+		ehdr->e_phoff = elf32_to_cpu(ehdr, buf_ehdr->e_phoff);
+		ehdr->e_shoff = elf32_to_cpu(ehdr, buf_ehdr->e_shoff);
+		break;
+
+	default:
+		pr_debug("Unknown ELF class.\n");
+		return -EINVAL;
+	}
+
+	return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC;
+}
+
+/**
+ * elf_is_phdr_sane - check that it is safe to use the program header
+ * @buf_len:	size of the buffer in which the ELF file is loaded.
+ */
+static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len)
+{
+
+	if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) {
+		pr_debug("ELF segment location wraps around.\n");
+		return false;
+	} else if (phdr->p_offset + phdr->p_filesz > buf_len) {
+		pr_debug("ELF segment not in file.\n");
+		return false;
+	} else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) {
+		pr_debug("ELF segment address wraps around.\n");
+		return false;
+	}
+
+	return true;
+}
+
+static int elf_read_phdr(const char *buf, size_t len,
+			 struct kexec_elf_info *elf_info,
+			 int idx)
+{
+	/* Override the const in proghdrs, we are the ones doing the loading. */
+	struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx];
+	const struct elfhdr *ehdr = elf_info->ehdr;
+	const char *pbuf;
+	struct elf_phdr *buf_phdr;
+
+	pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr));
+	buf_phdr = (struct elf_phdr *) pbuf;
+
+	phdr->p_type   = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type);
+	phdr->p_flags  = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags);
+
+	switch (ehdr->e_ident[EI_CLASS]) {
+	case ELFCLASS64:
+		phdr->p_offset = elf64_to_cpu(ehdr, buf_phdr->p_offset);
+		phdr->p_paddr  = elf64_to_cpu(ehdr, buf_phdr->p_paddr);
+		phdr->p_vaddr  = elf64_to_cpu(ehdr, buf_phdr->p_vaddr);
+		phdr->p_filesz = elf64_to_cpu(ehdr, buf_phdr->p_filesz);
+		phdr->p_memsz  = elf64_to_cpu(ehdr, buf_phdr->p_memsz);
+		phdr->p_align  = elf64_to_cpu(ehdr, buf_phdr->p_align);
+		break;
+
+	case ELFCLASS32:
+		phdr->p_offset = elf32_to_cpu(ehdr, buf_phdr->p_offset);
+		phdr->p_paddr  = elf32_to_cpu(ehdr, buf_phdr->p_paddr);
+		phdr->p_vaddr  = elf32_to_cpu(ehdr, buf_phdr->p_vaddr);
+		phdr->p_filesz = elf32_to_cpu(ehdr, buf_phdr->p_filesz);
+		phdr->p_memsz  = elf32_to_cpu(ehdr, buf_phdr->p_memsz);
+		phdr->p_align  = elf32_to_cpu(ehdr, buf_phdr->p_align);
+		break;
+
+	default:
+		pr_debug("Unknown ELF class.\n");
+		return -EINVAL;
+	}
+
+	return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC;
+}
+
+/**
+ * elf_read_phdrs - read the program headers from the buffer
+ *
+ * This function assumes that the program header table was checked for sanity.
+ * Use elf_is_ehdr_sane() if it wasn't.
+ */
+static int elf_read_phdrs(const char *buf, size_t len,
+			  struct kexec_elf_info *elf_info)
+{
+	size_t phdr_size, i;
+	const struct elfhdr *ehdr = elf_info->ehdr;
+
+	/*
+	 * e_phnum is at most 65535 so calculating the size of the
+	 * program header cannot overflow.
+	 */
+	phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum;
+
+	elf_info->proghdrs = kzalloc(phdr_size, GFP_KERNEL);
+	if (!elf_info->proghdrs)
+		return -ENOMEM;
+
+	for (i = 0; i < ehdr->e_phnum; i++) {
+		int ret;
+
+		ret = elf_read_phdr(buf, len, elf_info, i);
+		if (ret) {
+			kfree(elf_info->proghdrs);
+			elf_info->proghdrs = NULL;
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info
+ * @buf:	Buffer to read ELF file from.
+ * @len:	Size of @buf.
+ * @ehdr:	Pointer to existing struct which will be populated.
+ * @elf_info:	Pointer to existing struct which will be populated.
+ *
+ * This function allows reading ELF files with different byte order than
+ * the kernel, byte-swapping the fields as needed.
+ *
+ * Return:
+ * On success returns 0, and the caller should call
+ * kexec_free_elf_info(elf_info) to free the memory allocated for the section
+ * and program headers.
+ */
+static int elf_read_from_buffer(const char *buf, size_t len,
+				struct elfhdr *ehdr,
+				struct kexec_elf_info *elf_info)
+{
+	int ret;
+
+	ret = elf_read_ehdr(buf, len, ehdr);
+	if (ret)
+		return ret;
+
+	elf_info->buffer = buf;
+	elf_info->ehdr = ehdr;
+	if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) {
+		ret = elf_read_phdrs(buf, len, elf_info);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+/**
+ * kexec_free_elf_info - free memory allocated by elf_read_from_buffer
+ */
+void kexec_free_elf_info(struct kexec_elf_info *elf_info)
+{
+	kfree(elf_info->proghdrs);
+	memset(elf_info, 0, sizeof(*elf_info));
+}
+/**
+ * kexec_build_elf_info - read ELF executable and check that we can use it
+ */
+int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr,
+			       struct kexec_elf_info *elf_info)
+{
+	int i;
+	int ret;
+
+	ret = elf_read_from_buffer(buf, len, ehdr, elf_info);
+	if (ret)
+		return ret;
+
+	/* Big endian vmlinux has type ET_DYN. */
+	if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) {
+		pr_err("Not an ELF executable.\n");
+		goto error;
+	} else if (!elf_info->proghdrs) {
+		pr_err("No ELF program header.\n");
+		goto error;
+	}
+
+	for (i = 0; i < ehdr->e_phnum; i++) {
+		/*
+		 * Kexec does not support loading interpreters.
+		 * In addition this check keeps us from attempting
+		 * to kexec ordinay executables.
+		 */
+		if (elf_info->proghdrs[i].p_type == PT_INTERP) {
+			pr_err("Requires an ELF interpreter.\n");
+			goto error;
+		}
+	}
+
+	return 0;
+error:
+	kexec_free_elf_info(elf_info);
+	return -ENOEXEC;
+}
+
+
+int kexec_elf_probe(const char *buf, unsigned long len)
+{
+	struct elfhdr ehdr;
+	struct kexec_elf_info elf_info;
+	int ret;
+
+	ret = kexec_build_elf_info(buf, len, &ehdr, &elf_info);
+	if (ret)
+		return ret;
+
+	kexec_free_elf_info(&elf_info);
+
+	return elf_check_arch(&ehdr) ? 0 : -ENOEXEC;
+}
+
+/**
+ * kexec_elf_load - load ELF executable image
+ * @lowest_load_addr:	On return, will be the address where the first PT_LOAD
+ *			section will be loaded in memory.
+ *
+ * Return:
+ * 0 on success, negative value on failure.
+ */
+int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr,
+			 struct kexec_elf_info *elf_info,
+			 struct kexec_buf *kbuf,
+			 unsigned long *lowest_load_addr)
+{
+	unsigned long lowest_addr = UINT_MAX;
+	int ret;
+	size_t i;
+
+	/* Read in the PT_LOAD segments. */
+	for (i = 0; i < ehdr->e_phnum; i++) {
+		unsigned long load_addr;
+		size_t size;
+		const struct elf_phdr *phdr;
+
+		phdr = &elf_info->proghdrs[i];
+		if (phdr->p_type != PT_LOAD)
+			continue;
+
+		size = phdr->p_filesz;
+		if (size > phdr->p_memsz)
+			size = phdr->p_memsz;
+
+		kbuf->buffer = (void *) elf_info->buffer + phdr->p_offset;
+		kbuf->bufsz = size;
+		kbuf->memsz = phdr->p_memsz;
+		kbuf->buf_align = phdr->p_align;
+		kbuf->buf_min = phdr->p_paddr;
+		kbuf->mem = KEXEC_BUF_MEM_UNKNOWN;
+		ret = kexec_add_buffer(kbuf);
+		if (ret)
+			goto out;
+		load_addr = kbuf->mem;
+
+		if (load_addr < lowest_addr)
+			lowest_addr = load_addr;
+	}
+
+	*lowest_load_addr = lowest_addr;
+	ret = 0;
+ out:
+	return ret;
+}
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
new file mode 100644
index 000000000..6d787ae9d
--- /dev/null
+++ b/kernel/kexec_file.c
@@ -0,0 +1,1330 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kexec: kexec_file_load system call
+ *
+ * Copyright (C) 2014 Red Hat Inc.
+ * Authors:
+ *      Vivek Goyal <vgoyal@redhat.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/capability.h>
+#include <linux/mm.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/kexec.h>
+#include <linux/memblock.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/ima.h>
+#include <crypto/hash.h>
+#include <crypto/sha2.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/kernel.h>
+#include <linux/kernel_read_file.h>
+#include <linux/syscalls.h>
+#include <linux/vmalloc.h>
+#include "kexec_internal.h"
+
+#ifdef CONFIG_KEXEC_SIG
+static bool sig_enforce = IS_ENABLED(CONFIG_KEXEC_SIG_FORCE);
+
+void set_kexec_sig_enforced(void)
+{
+	sig_enforce = true;
+}
+#endif
+
+static int kexec_calculate_store_digests(struct kimage *image);
+
+/* Maximum size in bytes for kernel/initrd files. */
+#define KEXEC_FILE_SIZE_MAX	min_t(s64, 4LL << 30, SSIZE_MAX)
+
+/*
+ * Currently this is the only default function that is exported as some
+ * architectures need it to do additional handlings.
+ * In the future, other default functions may be exported too if required.
+ */
+int kexec_image_probe_default(struct kimage *image, void *buf,
+			      unsigned long buf_len)
+{
+	const struct kexec_file_ops * const *fops;
+	int ret = -ENOEXEC;
+
+	for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
+		ret = (*fops)->probe(buf, buf_len);
+		if (!ret) {
+			image->fops = *fops;
+			return ret;
+		}
+	}
+
+	return ret;
+}
+
+void *kexec_image_load_default(struct kimage *image)
+{
+	if (!image->fops || !image->fops->load)
+		return ERR_PTR(-ENOEXEC);
+
+	return image->fops->load(image, image->kernel_buf,
+				 image->kernel_buf_len, image->initrd_buf,
+				 image->initrd_buf_len, image->cmdline_buf,
+				 image->cmdline_buf_len);
+}
+
+int kexec_image_post_load_cleanup_default(struct kimage *image)
+{
+	if (!image->fops || !image->fops->cleanup)
+		return 0;
+
+	return image->fops->cleanup(image->image_loader_data);
+}
+
+/*
+ * Free up memory used by kernel, initrd, and command line. This is temporary
+ * memory allocation which is not needed any more after these buffers have
+ * been loaded into separate segments and have been copied elsewhere.
+ */
+void kimage_file_post_load_cleanup(struct kimage *image)
+{
+	struct purgatory_info *pi = &image->purgatory_info;
+
+	vfree(image->kernel_buf);
+	image->kernel_buf = NULL;
+
+	vfree(image->initrd_buf);
+	image->initrd_buf = NULL;
+
+	kfree(image->cmdline_buf);
+	image->cmdline_buf = NULL;
+
+	vfree(pi->purgatory_buf);
+	pi->purgatory_buf = NULL;
+
+	vfree(pi->sechdrs);
+	pi->sechdrs = NULL;
+
+#ifdef CONFIG_IMA_KEXEC
+	vfree(image->ima_buffer);
+	image->ima_buffer = NULL;
+#endif /* CONFIG_IMA_KEXEC */
+
+	/* See if architecture has anything to cleanup post load */
+	arch_kimage_file_post_load_cleanup(image);
+
+	/*
+	 * Above call should have called into bootloader to free up
+	 * any data stored in kimage->image_loader_data. It should
+	 * be ok now to free it up.
+	 */
+	kfree(image->image_loader_data);
+	image->image_loader_data = NULL;
+}
+
+#ifdef CONFIG_KEXEC_SIG
+#ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
+int kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len)
+{
+	int ret;
+
+	ret = verify_pefile_signature(kernel, kernel_len,
+				      VERIFY_USE_SECONDARY_KEYRING,
+				      VERIFYING_KEXEC_PE_SIGNATURE);
+	if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
+		ret = verify_pefile_signature(kernel, kernel_len,
+					      VERIFY_USE_PLATFORM_KEYRING,
+					      VERIFYING_KEXEC_PE_SIGNATURE);
+	}
+	return ret;
+}
+#endif
+
+static int kexec_image_verify_sig(struct kimage *image, void *buf,
+				  unsigned long buf_len)
+{
+	if (!image->fops || !image->fops->verify_sig) {
+		pr_debug("kernel loader does not support signature verification.\n");
+		return -EKEYREJECTED;
+	}
+
+	return image->fops->verify_sig(buf, buf_len);
+}
+
+static int
+kimage_validate_signature(struct kimage *image)
+{
+	int ret;
+
+	ret = kexec_image_verify_sig(image, image->kernel_buf,
+				     image->kernel_buf_len);
+	if (ret) {
+
+		if (sig_enforce) {
+			pr_notice("Enforced kernel signature verification failed (%d).\n", ret);
+			return ret;
+		}
+
+		/*
+		 * If IMA is guaranteed to appraise a signature on the kexec
+		 * image, permit it even if the kernel is otherwise locked
+		 * down.
+		 */
+		if (!ima_appraise_signature(READING_KEXEC_IMAGE) &&
+		    security_locked_down(LOCKDOWN_KEXEC))
+			return -EPERM;
+
+		pr_debug("kernel signature verification failed (%d).\n", ret);
+	}
+
+	return 0;
+}
+#endif
+
+/*
+ * In file mode list of segments is prepared by kernel. Copy relevant
+ * data from user space, do error checking, prepare segment list
+ */
+static int
+kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
+			     const char __user *cmdline_ptr,
+			     unsigned long cmdline_len, unsigned flags)
+{
+	ssize_t ret;
+	void *ldata;
+
+	ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf,
+				       KEXEC_FILE_SIZE_MAX, NULL,
+				       READING_KEXEC_IMAGE);
+	if (ret < 0)
+		return ret;
+	image->kernel_buf_len = ret;
+
+	/* Call arch image probe handlers */
+	ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
+					    image->kernel_buf_len);
+	if (ret)
+		goto out;
+
+#ifdef CONFIG_KEXEC_SIG
+	ret = kimage_validate_signature(image);
+
+	if (ret)
+		goto out;
+#endif
+	/* It is possible that there no initramfs is being loaded */
+	if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
+		ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf,
+					       KEXEC_FILE_SIZE_MAX, NULL,
+					       READING_KEXEC_INITRAMFS);
+		if (ret < 0)
+			goto out;
+		image->initrd_buf_len = ret;
+		ret = 0;
+	}
+
+	if (cmdline_len) {
+		image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
+		if (IS_ERR(image->cmdline_buf)) {
+			ret = PTR_ERR(image->cmdline_buf);
+			image->cmdline_buf = NULL;
+			goto out;
+		}
+
+		image->cmdline_buf_len = cmdline_len;
+
+		/* command line should be a string with last byte null */
+		if (image->cmdline_buf[cmdline_len - 1] != '\0') {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		ima_kexec_cmdline(kernel_fd, image->cmdline_buf,
+				  image->cmdline_buf_len - 1);
+	}
+
+	/* IMA needs to pass the measurement list to the next kernel. */
+	ima_add_kexec_buffer(image);
+
+	/* Call arch image load handlers */
+	ldata = arch_kexec_kernel_image_load(image);
+
+	if (IS_ERR(ldata)) {
+		ret = PTR_ERR(ldata);
+		goto out;
+	}
+
+	image->image_loader_data = ldata;
+out:
+	/* In case of error, free up all allocated memory in this function */
+	if (ret)
+		kimage_file_post_load_cleanup(image);
+	return ret;
+}
+
+static int
+kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
+		       int initrd_fd, const char __user *cmdline_ptr,
+		       unsigned long cmdline_len, unsigned long flags)
+{
+	int ret;
+	struct kimage *image;
+	bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
+
+	image = do_kimage_alloc_init();
+	if (!image)
+		return -ENOMEM;
+
+	image->file_mode = 1;
+
+	if (kexec_on_panic) {
+		/* Enable special crash kernel control page alloc policy. */
+		image->control_page = crashk_res.start;
+		image->type = KEXEC_TYPE_CRASH;
+	}
+
+	ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
+					   cmdline_ptr, cmdline_len, flags);
+	if (ret)
+		goto out_free_image;
+
+	ret = sanity_check_segment_list(image);
+	if (ret)
+		goto out_free_post_load_bufs;
+
+	ret = -ENOMEM;
+	image->control_code_page = kimage_alloc_control_pages(image,
+					   get_order(KEXEC_CONTROL_PAGE_SIZE));
+	if (!image->control_code_page) {
+		pr_err("Could not allocate control_code_buffer\n");
+		goto out_free_post_load_bufs;
+	}
+
+	if (!kexec_on_panic) {
+		image->swap_page = kimage_alloc_control_pages(image, 0);
+		if (!image->swap_page) {
+			pr_err("Could not allocate swap buffer\n");
+			goto out_free_control_pages;
+		}
+	}
+
+	*rimage = image;
+	return 0;
+out_free_control_pages:
+	kimage_free_page_list(&image->control_pages);
+out_free_post_load_bufs:
+	kimage_file_post_load_cleanup(image);
+out_free_image:
+	kfree(image);
+	return ret;
+}
+
+SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
+		unsigned long, cmdline_len, const char __user *, cmdline_ptr,
+		unsigned long, flags)
+{
+	int ret = 0, i;
+	struct kimage **dest_image, *image;
+
+	/* We only trust the superuser with rebooting the system. */
+	if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
+		return -EPERM;
+
+	/* Make sure we have a legal set of flags */
+	if (flags != (flags & KEXEC_FILE_FLAGS))
+		return -EINVAL;
+
+	image = NULL;
+
+	if (!kexec_trylock())
+		return -EBUSY;
+
+	dest_image = &kexec_image;
+	if (flags & KEXEC_FILE_ON_CRASH) {
+		dest_image = &kexec_crash_image;
+		if (kexec_crash_image)
+			arch_kexec_unprotect_crashkres();
+	}
+
+	if (flags & KEXEC_FILE_UNLOAD)
+		goto exchange;
+
+	/*
+	 * In case of crash, new kernel gets loaded in reserved region. It is
+	 * same memory where old crash kernel might be loaded. Free any
+	 * current crash dump kernel before we corrupt it.
+	 */
+	if (flags & KEXEC_FILE_ON_CRASH)
+		kimage_free(xchg(&kexec_crash_image, NULL));
+
+	ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
+				     cmdline_len, flags);
+	if (ret)
+		goto out;
+
+	ret = machine_kexec_prepare(image);
+	if (ret)
+		goto out;
+
+	/*
+	 * Some architecture(like S390) may touch the crash memory before
+	 * machine_kexec_prepare(), we must copy vmcoreinfo data after it.
+	 */
+	ret = kimage_crash_copy_vmcoreinfo(image);
+	if (ret)
+		goto out;
+
+	ret = kexec_calculate_store_digests(image);
+	if (ret)
+		goto out;
+
+	for (i = 0; i < image->nr_segments; i++) {
+		struct kexec_segment *ksegment;
+
+		ksegment = &image->segment[i];
+		pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
+			 i, ksegment->buf, ksegment->bufsz, ksegment->mem,
+			 ksegment->memsz);
+
+		ret = kimage_load_segment(image, &image->segment[i]);
+		if (ret)
+			goto out;
+	}
+
+	kimage_terminate(image);
+
+	ret = machine_kexec_post_load(image);
+	if (ret)
+		goto out;
+
+	/*
+	 * Free up any temporary buffers allocated which are not needed
+	 * after image has been loaded
+	 */
+	kimage_file_post_load_cleanup(image);
+exchange:
+	image = xchg(dest_image, image);
+out:
+	if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
+		arch_kexec_protect_crashkres();
+
+	kexec_unlock();
+	kimage_free(image);
+	return ret;
+}
+
+static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
+				    struct kexec_buf *kbuf)
+{
+	struct kimage *image = kbuf->image;
+	unsigned long temp_start, temp_end;
+
+	temp_end = min(end, kbuf->buf_max);
+	temp_start = temp_end - kbuf->memsz;
+
+	do {
+		/* align down start */
+		temp_start = temp_start & (~(kbuf->buf_align - 1));
+
+		if (temp_start < start || temp_start < kbuf->buf_min)
+			return 0;
+
+		temp_end = temp_start + kbuf->memsz - 1;
+
+		/*
+		 * Make sure this does not conflict with any of existing
+		 * segments
+		 */
+		if (kimage_is_destination_range(image, temp_start, temp_end)) {
+			temp_start = temp_start - PAGE_SIZE;
+			continue;
+		}
+
+		/* We found a suitable memory range */
+		break;
+	} while (1);
+
+	/* If we are here, we found a suitable memory range */
+	kbuf->mem = temp_start;
+
+	/* Success, stop navigating through remaining System RAM ranges */
+	return 1;
+}
+
+static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
+				     struct kexec_buf *kbuf)
+{
+	struct kimage *image = kbuf->image;
+	unsigned long temp_start, temp_end;
+
+	temp_start = max(start, kbuf->buf_min);
+
+	do {
+		temp_start = ALIGN(temp_start, kbuf->buf_align);
+		temp_end = temp_start + kbuf->memsz - 1;
+
+		if (temp_end > end || temp_end > kbuf->buf_max)
+			return 0;
+		/*
+		 * Make sure this does not conflict with any of existing
+		 * segments
+		 */
+		if (kimage_is_destination_range(image, temp_start, temp_end)) {
+			temp_start = temp_start + PAGE_SIZE;
+			continue;
+		}
+
+		/* We found a suitable memory range */
+		break;
+	} while (1);
+
+	/* If we are here, we found a suitable memory range */
+	kbuf->mem = temp_start;
+
+	/* Success, stop navigating through remaining System RAM ranges */
+	return 1;
+}
+
+static int locate_mem_hole_callback(struct resource *res, void *arg)
+{
+	struct kexec_buf *kbuf = (struct kexec_buf *)arg;
+	u64 start = res->start, end = res->end;
+	unsigned long sz = end - start + 1;
+
+	/* Returning 0 will take to next memory range */
+
+	/* Don't use memory that will be detected and handled by a driver. */
+	if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
+		return 0;
+
+	if (sz < kbuf->memsz)
+		return 0;
+
+	if (end < kbuf->buf_min || start > kbuf->buf_max)
+		return 0;
+
+	/*
+	 * Allocate memory top down with-in ram range. Otherwise bottom up
+	 * allocation.
+	 */
+	if (kbuf->top_down)
+		return locate_mem_hole_top_down(start, end, kbuf);
+	return locate_mem_hole_bottom_up(start, end, kbuf);
+}
+
+#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
+static int kexec_walk_memblock(struct kexec_buf *kbuf,
+			       int (*func)(struct resource *, void *))
+{
+	int ret = 0;
+	u64 i;
+	phys_addr_t mstart, mend;
+	struct resource res = { };
+
+	if (kbuf->image->type == KEXEC_TYPE_CRASH)
+		return func(&crashk_res, kbuf);
+
+	/*
+	 * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See
+	 * IORESOURCE_SYSRAM_DRIVER_MANAGED handling in
+	 * locate_mem_hole_callback().
+	 */
+	if (kbuf->top_down) {
+		for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
+						&mstart, &mend, NULL) {
+			/*
+			 * In memblock, end points to the first byte after the
+			 * range while in kexec, end points to the last byte
+			 * in the range.
+			 */
+			res.start = mstart;
+			res.end = mend - 1;
+			ret = func(&res, kbuf);
+			if (ret)
+				break;
+		}
+	} else {
+		for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
+					&mstart, &mend, NULL) {
+			/*
+			 * In memblock, end points to the first byte after the
+			 * range while in kexec, end points to the last byte
+			 * in the range.
+			 */
+			res.start = mstart;
+			res.end = mend - 1;
+			ret = func(&res, kbuf);
+			if (ret)
+				break;
+		}
+	}
+
+	return ret;
+}
+#else
+static int kexec_walk_memblock(struct kexec_buf *kbuf,
+			       int (*func)(struct resource *, void *))
+{
+	return 0;
+}
+#endif
+
+/**
+ * kexec_walk_resources - call func(data) on free memory regions
+ * @kbuf:	Context info for the search. Also passed to @func.
+ * @func:	Function to call for each memory region.
+ *
+ * Return: The memory walk will stop when func returns a non-zero value
+ * and that value will be returned. If all free regions are visited without
+ * func returning non-zero, then zero will be returned.
+ */
+static int kexec_walk_resources(struct kexec_buf *kbuf,
+				int (*func)(struct resource *, void *))
+{
+	if (kbuf->image->type == KEXEC_TYPE_CRASH)
+		return walk_iomem_res_desc(crashk_res.desc,
+					   IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
+					   crashk_res.start, crashk_res.end,
+					   kbuf, func);
+	else
+		return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
+}
+
+/**
+ * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
+ * @kbuf:	Parameters for the memory search.
+ *
+ * On success, kbuf->mem will have the start address of the memory region found.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int kexec_locate_mem_hole(struct kexec_buf *kbuf)
+{
+	int ret;
+
+	/* Arch knows where to place */
+	if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
+		return 0;
+
+	if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
+		ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
+	else
+		ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
+
+	return ret == 1 ? 0 : -EADDRNOTAVAIL;
+}
+
+/**
+ * kexec_add_buffer - place a buffer in a kexec segment
+ * @kbuf:	Buffer contents and memory parameters.
+ *
+ * This function assumes that kexec_mutex is held.
+ * On successful return, @kbuf->mem will have the physical address of
+ * the buffer in memory.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int kexec_add_buffer(struct kexec_buf *kbuf)
+{
+	struct kexec_segment *ksegment;
+	int ret;
+
+	/* Currently adding segment this way is allowed only in file mode */
+	if (!kbuf->image->file_mode)
+		return -EINVAL;
+
+	if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
+		return -EINVAL;
+
+	/*
+	 * Make sure we are not trying to add buffer after allocating
+	 * control pages. All segments need to be placed first before
+	 * any control pages are allocated. As control page allocation
+	 * logic goes through list of segments to make sure there are
+	 * no destination overlaps.
+	 */
+	if (!list_empty(&kbuf->image->control_pages)) {
+		WARN_ON(1);
+		return -EINVAL;
+	}
+
+	/* Ensure minimum alignment needed for segments. */
+	kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
+	kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
+
+	/* Walk the RAM ranges and allocate a suitable range for the buffer */
+	ret = arch_kexec_locate_mem_hole(kbuf);
+	if (ret)
+		return ret;
+
+	/* Found a suitable memory range */
+	ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
+	ksegment->kbuf = kbuf->buffer;
+	ksegment->bufsz = kbuf->bufsz;
+	ksegment->mem = kbuf->mem;
+	ksegment->memsz = kbuf->memsz;
+	kbuf->image->nr_segments++;
+	return 0;
+}
+
+/* Calculate and store the digest of segments */
+static int kexec_calculate_store_digests(struct kimage *image)
+{
+	struct crypto_shash *tfm;
+	struct shash_desc *desc;
+	int ret = 0, i, j, zero_buf_sz, sha_region_sz;
+	size_t desc_size, nullsz;
+	char *digest;
+	void *zero_buf;
+	struct kexec_sha_region *sha_regions;
+	struct purgatory_info *pi = &image->purgatory_info;
+
+	if (!IS_ENABLED(CONFIG_ARCH_HAS_KEXEC_PURGATORY))
+		return 0;
+
+	zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
+	zero_buf_sz = PAGE_SIZE;
+
+	tfm = crypto_alloc_shash("sha256", 0, 0);
+	if (IS_ERR(tfm)) {
+		ret = PTR_ERR(tfm);
+		goto out;
+	}
+
+	desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
+	desc = kzalloc(desc_size, GFP_KERNEL);
+	if (!desc) {
+		ret = -ENOMEM;
+		goto out_free_tfm;
+	}
+
+	sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
+	sha_regions = vzalloc(sha_region_sz);
+	if (!sha_regions) {
+		ret = -ENOMEM;
+		goto out_free_desc;
+	}
+
+	desc->tfm   = tfm;
+
+	ret = crypto_shash_init(desc);
+	if (ret < 0)
+		goto out_free_sha_regions;
+
+	digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
+	if (!digest) {
+		ret = -ENOMEM;
+		goto out_free_sha_regions;
+	}
+
+	for (j = i = 0; i < image->nr_segments; i++) {
+		struct kexec_segment *ksegment;
+
+		ksegment = &image->segment[i];
+		/*
+		 * Skip purgatory as it will be modified once we put digest
+		 * info in purgatory.
+		 */
+		if (ksegment->kbuf == pi->purgatory_buf)
+			continue;
+
+		ret = crypto_shash_update(desc, ksegment->kbuf,
+					  ksegment->bufsz);
+		if (ret)
+			break;
+
+		/*
+		 * Assume rest of the buffer is filled with zero and
+		 * update digest accordingly.
+		 */
+		nullsz = ksegment->memsz - ksegment->bufsz;
+		while (nullsz) {
+			unsigned long bytes = nullsz;
+
+			if (bytes > zero_buf_sz)
+				bytes = zero_buf_sz;
+			ret = crypto_shash_update(desc, zero_buf, bytes);
+			if (ret)
+				break;
+			nullsz -= bytes;
+		}
+
+		if (ret)
+			break;
+
+		sha_regions[j].start = ksegment->mem;
+		sha_regions[j].len = ksegment->memsz;
+		j++;
+	}
+
+	if (!ret) {
+		ret = crypto_shash_final(desc, digest);
+		if (ret)
+			goto out_free_digest;
+		ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
+						     sha_regions, sha_region_sz, 0);
+		if (ret)
+			goto out_free_digest;
+
+		ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
+						     digest, SHA256_DIGEST_SIZE, 0);
+		if (ret)
+			goto out_free_digest;
+	}
+
+out_free_digest:
+	kfree(digest);
+out_free_sha_regions:
+	vfree(sha_regions);
+out_free_desc:
+	kfree(desc);
+out_free_tfm:
+	kfree(tfm);
+out:
+	return ret;
+}
+
+#ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY
+/*
+ * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
+ * @pi:		Purgatory to be loaded.
+ * @kbuf:	Buffer to setup.
+ *
+ * Allocates the memory needed for the buffer. Caller is responsible to free
+ * the memory after use.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
+				      struct kexec_buf *kbuf)
+{
+	const Elf_Shdr *sechdrs;
+	unsigned long bss_align;
+	unsigned long bss_sz;
+	unsigned long align;
+	int i, ret;
+
+	sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
+	kbuf->buf_align = bss_align = 1;
+	kbuf->bufsz = bss_sz = 0;
+
+	for (i = 0; i < pi->ehdr->e_shnum; i++) {
+		if (!(sechdrs[i].sh_flags & SHF_ALLOC))
+			continue;
+
+		align = sechdrs[i].sh_addralign;
+		if (sechdrs[i].sh_type != SHT_NOBITS) {
+			if (kbuf->buf_align < align)
+				kbuf->buf_align = align;
+			kbuf->bufsz = ALIGN(kbuf->bufsz, align);
+			kbuf->bufsz += sechdrs[i].sh_size;
+		} else {
+			if (bss_align < align)
+				bss_align = align;
+			bss_sz = ALIGN(bss_sz, align);
+			bss_sz += sechdrs[i].sh_size;
+		}
+	}
+	kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
+	kbuf->memsz = kbuf->bufsz + bss_sz;
+	if (kbuf->buf_align < bss_align)
+		kbuf->buf_align = bss_align;
+
+	kbuf->buffer = vzalloc(kbuf->bufsz);
+	if (!kbuf->buffer)
+		return -ENOMEM;
+	pi->purgatory_buf = kbuf->buffer;
+
+	ret = kexec_add_buffer(kbuf);
+	if (ret)
+		goto out;
+
+	return 0;
+out:
+	vfree(pi->purgatory_buf);
+	pi->purgatory_buf = NULL;
+	return ret;
+}
+
+/*
+ * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
+ * @pi:		Purgatory to be loaded.
+ * @kbuf:	Buffer prepared to store purgatory.
+ *
+ * Allocates the memory needed for the buffer. Caller is responsible to free
+ * the memory after use.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
+					 struct kexec_buf *kbuf)
+{
+	unsigned long bss_addr;
+	unsigned long offset;
+	Elf_Shdr *sechdrs;
+	int i;
+
+	/*
+	 * The section headers in kexec_purgatory are read-only. In order to
+	 * have them modifiable make a temporary copy.
+	 */
+	sechdrs = vzalloc(array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum));
+	if (!sechdrs)
+		return -ENOMEM;
+	memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff,
+	       pi->ehdr->e_shnum * sizeof(Elf_Shdr));
+	pi->sechdrs = sechdrs;
+
+	offset = 0;
+	bss_addr = kbuf->mem + kbuf->bufsz;
+	kbuf->image->start = pi->ehdr->e_entry;
+
+	for (i = 0; i < pi->ehdr->e_shnum; i++) {
+		unsigned long align;
+		void *src, *dst;
+
+		if (!(sechdrs[i].sh_flags & SHF_ALLOC))
+			continue;
+
+		align = sechdrs[i].sh_addralign;
+		if (sechdrs[i].sh_type == SHT_NOBITS) {
+			bss_addr = ALIGN(bss_addr, align);
+			sechdrs[i].sh_addr = bss_addr;
+			bss_addr += sechdrs[i].sh_size;
+			continue;
+		}
+
+		offset = ALIGN(offset, align);
+
+		/*
+		 * Check if the segment contains the entry point, if so,
+		 * calculate the value of image->start based on it.
+		 * If the compiler has produced more than one .text section
+		 * (Eg: .text.hot), they are generally after the main .text
+		 * section, and they shall not be used to calculate
+		 * image->start. So do not re-calculate image->start if it
+		 * is not set to the initial value, and warn the user so they
+		 * have a chance to fix their purgatory's linker script.
+		 */
+		if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
+		    pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
+		    pi->ehdr->e_entry < (sechdrs[i].sh_addr
+					 + sechdrs[i].sh_size) &&
+		    !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) {
+			kbuf->image->start -= sechdrs[i].sh_addr;
+			kbuf->image->start += kbuf->mem + offset;
+		}
+
+		src = (void *)pi->ehdr + sechdrs[i].sh_offset;
+		dst = pi->purgatory_buf + offset;
+		memcpy(dst, src, sechdrs[i].sh_size);
+
+		sechdrs[i].sh_addr = kbuf->mem + offset;
+		sechdrs[i].sh_offset = offset;
+		offset += sechdrs[i].sh_size;
+	}
+
+	return 0;
+}
+
+static int kexec_apply_relocations(struct kimage *image)
+{
+	int i, ret;
+	struct purgatory_info *pi = &image->purgatory_info;
+	const Elf_Shdr *sechdrs;
+
+	sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
+
+	for (i = 0; i < pi->ehdr->e_shnum; i++) {
+		const Elf_Shdr *relsec;
+		const Elf_Shdr *symtab;
+		Elf_Shdr *section;
+
+		relsec = sechdrs + i;
+
+		if (relsec->sh_type != SHT_RELA &&
+		    relsec->sh_type != SHT_REL)
+			continue;
+
+		/*
+		 * For section of type SHT_RELA/SHT_REL,
+		 * ->sh_link contains section header index of associated
+		 * symbol table. And ->sh_info contains section header
+		 * index of section to which relocations apply.
+		 */
+		if (relsec->sh_info >= pi->ehdr->e_shnum ||
+		    relsec->sh_link >= pi->ehdr->e_shnum)
+			return -ENOEXEC;
+
+		section = pi->sechdrs + relsec->sh_info;
+		symtab = sechdrs + relsec->sh_link;
+
+		if (!(section->sh_flags & SHF_ALLOC))
+			continue;
+
+		/*
+		 * symtab->sh_link contain section header index of associated
+		 * string table.
+		 */
+		if (symtab->sh_link >= pi->ehdr->e_shnum)
+			/* Invalid section number? */
+			continue;
+
+		/*
+		 * Respective architecture needs to provide support for applying
+		 * relocations of type SHT_RELA/SHT_REL.
+		 */
+		if (relsec->sh_type == SHT_RELA)
+			ret = arch_kexec_apply_relocations_add(pi, section,
+							       relsec, symtab);
+		else if (relsec->sh_type == SHT_REL)
+			ret = arch_kexec_apply_relocations(pi, section,
+							   relsec, symtab);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * kexec_load_purgatory - Load and relocate the purgatory object.
+ * @image:	Image to add the purgatory to.
+ * @kbuf:	Memory parameters to use.
+ *
+ * Allocates the memory needed for image->purgatory_info.sechdrs and
+ * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
+ * to free the memory after use.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
+{
+	struct purgatory_info *pi = &image->purgatory_info;
+	int ret;
+
+	if (kexec_purgatory_size <= 0)
+		return -EINVAL;
+
+	pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
+
+	ret = kexec_purgatory_setup_kbuf(pi, kbuf);
+	if (ret)
+		return ret;
+
+	ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
+	if (ret)
+		goto out_free_kbuf;
+
+	ret = kexec_apply_relocations(image);
+	if (ret)
+		goto out;
+
+	return 0;
+out:
+	vfree(pi->sechdrs);
+	pi->sechdrs = NULL;
+out_free_kbuf:
+	vfree(pi->purgatory_buf);
+	pi->purgatory_buf = NULL;
+	return ret;
+}
+
+/*
+ * kexec_purgatory_find_symbol - find a symbol in the purgatory
+ * @pi:		Purgatory to search in.
+ * @name:	Name of the symbol.
+ *
+ * Return: pointer to symbol in read-only symtab on success, NULL on error.
+ */
+static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
+						  const char *name)
+{
+	const Elf_Shdr *sechdrs;
+	const Elf_Ehdr *ehdr;
+	const Elf_Sym *syms;
+	const char *strtab;
+	int i, k;
+
+	if (!pi->ehdr)
+		return NULL;
+
+	ehdr = pi->ehdr;
+	sechdrs = (void *)ehdr + ehdr->e_shoff;
+
+	for (i = 0; i < ehdr->e_shnum; i++) {
+		if (sechdrs[i].sh_type != SHT_SYMTAB)
+			continue;
+
+		if (sechdrs[i].sh_link >= ehdr->e_shnum)
+			/* Invalid strtab section number */
+			continue;
+		strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
+		syms = (void *)ehdr + sechdrs[i].sh_offset;
+
+		/* Go through symbols for a match */
+		for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
+			if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
+				continue;
+
+			if (strcmp(strtab + syms[k].st_name, name) != 0)
+				continue;
+
+			if (syms[k].st_shndx == SHN_UNDEF ||
+			    syms[k].st_shndx >= ehdr->e_shnum) {
+				pr_debug("Symbol: %s has bad section index %d.\n",
+						name, syms[k].st_shndx);
+				return NULL;
+			}
+
+			/* Found the symbol we are looking for */
+			return &syms[k];
+		}
+	}
+
+	return NULL;
+}
+
+void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
+{
+	struct purgatory_info *pi = &image->purgatory_info;
+	const Elf_Sym *sym;
+	Elf_Shdr *sechdr;
+
+	sym = kexec_purgatory_find_symbol(pi, name);
+	if (!sym)
+		return ERR_PTR(-EINVAL);
+
+	sechdr = &pi->sechdrs[sym->st_shndx];
+
+	/*
+	 * Returns the address where symbol will finally be loaded after
+	 * kexec_load_segment()
+	 */
+	return (void *)(sechdr->sh_addr + sym->st_value);
+}
+
+/*
+ * Get or set value of a symbol. If "get_value" is true, symbol value is
+ * returned in buf otherwise symbol value is set based on value in buf.
+ */
+int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
+				   void *buf, unsigned int size, bool get_value)
+{
+	struct purgatory_info *pi = &image->purgatory_info;
+	const Elf_Sym *sym;
+	Elf_Shdr *sec;
+	char *sym_buf;
+
+	sym = kexec_purgatory_find_symbol(pi, name);
+	if (!sym)
+		return -EINVAL;
+
+	if (sym->st_size != size) {
+		pr_err("symbol %s size mismatch: expected %lu actual %u\n",
+		       name, (unsigned long)sym->st_size, size);
+		return -EINVAL;
+	}
+
+	sec = pi->sechdrs + sym->st_shndx;
+
+	if (sec->sh_type == SHT_NOBITS) {
+		pr_err("symbol %s is in a bss section. Cannot %s\n", name,
+		       get_value ? "get" : "set");
+		return -EINVAL;
+	}
+
+	sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
+
+	if (get_value)
+		memcpy((void *)buf, sym_buf, size);
+	else
+		memcpy((void *)sym_buf, buf, size);
+
+	return 0;
+}
+#endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */
+
+int crash_exclude_mem_range(struct crash_mem *mem,
+			    unsigned long long mstart, unsigned long long mend)
+{
+	int i, j;
+	unsigned long long start, end, p_start, p_end;
+	struct crash_mem_range temp_range = {0, 0};
+
+	for (i = 0; i < mem->nr_ranges; i++) {
+		start = mem->ranges[i].start;
+		end = mem->ranges[i].end;
+		p_start = mstart;
+		p_end = mend;
+
+		if (mstart > end || mend < start)
+			continue;
+
+		/* Truncate any area outside of range */
+		if (mstart < start)
+			p_start = start;
+		if (mend > end)
+			p_end = end;
+
+		/* Found completely overlapping range */
+		if (p_start == start && p_end == end) {
+			mem->ranges[i].start = 0;
+			mem->ranges[i].end = 0;
+			if (i < mem->nr_ranges - 1) {
+				/* Shift rest of the ranges to left */
+				for (j = i; j < mem->nr_ranges - 1; j++) {
+					mem->ranges[j].start =
+						mem->ranges[j+1].start;
+					mem->ranges[j].end =
+							mem->ranges[j+1].end;
+				}
+
+				/*
+				 * Continue to check if there are another overlapping ranges
+				 * from the current position because of shifting the above
+				 * mem ranges.
+				 */
+				i--;
+				mem->nr_ranges--;
+				continue;
+			}
+			mem->nr_ranges--;
+			return 0;
+		}
+
+		if (p_start > start && p_end < end) {
+			/* Split original range */
+			mem->ranges[i].end = p_start - 1;
+			temp_range.start = p_end + 1;
+			temp_range.end = end;
+		} else if (p_start != start)
+			mem->ranges[i].end = p_start - 1;
+		else
+			mem->ranges[i].start = p_end + 1;
+		break;
+	}
+
+	/* If a split happened, add the split to array */
+	if (!temp_range.end)
+		return 0;
+
+	/* Split happened */
+	if (i == mem->max_nr_ranges - 1)
+		return -ENOMEM;
+
+	/* Location where new range should go */
+	j = i + 1;
+	if (j < mem->nr_ranges) {
+		/* Move over all ranges one slot towards the end */
+		for (i = mem->nr_ranges - 1; i >= j; i--)
+			mem->ranges[i + 1] = mem->ranges[i];
+	}
+
+	mem->ranges[j].start = temp_range.start;
+	mem->ranges[j].end = temp_range.end;
+	mem->nr_ranges++;
+	return 0;
+}
+
+int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
+			  void **addr, unsigned long *sz)
+{
+	Elf64_Ehdr *ehdr;
+	Elf64_Phdr *phdr;
+	unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
+	unsigned char *buf;
+	unsigned int cpu, i;
+	unsigned long long notes_addr;
+	unsigned long mstart, mend;
+
+	/* extra phdr for vmcoreinfo ELF note */
+	nr_phdr = nr_cpus + 1;
+	nr_phdr += mem->nr_ranges;
+
+	/*
+	 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
+	 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
+	 * I think this is required by tools like gdb. So same physical
+	 * memory will be mapped in two ELF headers. One will contain kernel
+	 * text virtual addresses and other will have __va(physical) addresses.
+	 */
+
+	nr_phdr++;
+	elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
+	elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
+
+	buf = vzalloc(elf_sz);
+	if (!buf)
+		return -ENOMEM;
+
+	ehdr = (Elf64_Ehdr *)buf;
+	phdr = (Elf64_Phdr *)(ehdr + 1);
+	memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
+	ehdr->e_ident[EI_CLASS] = ELFCLASS64;
+	ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
+	ehdr->e_ident[EI_VERSION] = EV_CURRENT;
+	ehdr->e_ident[EI_OSABI] = ELF_OSABI;
+	memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
+	ehdr->e_type = ET_CORE;
+	ehdr->e_machine = ELF_ARCH;
+	ehdr->e_version = EV_CURRENT;
+	ehdr->e_phoff = sizeof(Elf64_Ehdr);
+	ehdr->e_ehsize = sizeof(Elf64_Ehdr);
+	ehdr->e_phentsize = sizeof(Elf64_Phdr);
+
+	/* Prepare one phdr of type PT_NOTE for each present CPU */
+	for_each_present_cpu(cpu) {
+		phdr->p_type = PT_NOTE;
+		notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
+		phdr->p_offset = phdr->p_paddr = notes_addr;
+		phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
+		(ehdr->e_phnum)++;
+		phdr++;
+	}
+
+	/* Prepare one PT_NOTE header for vmcoreinfo */
+	phdr->p_type = PT_NOTE;
+	phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
+	phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
+	(ehdr->e_phnum)++;
+	phdr++;
+
+	/* Prepare PT_LOAD type program header for kernel text region */
+	if (need_kernel_map) {
+		phdr->p_type = PT_LOAD;
+		phdr->p_flags = PF_R|PF_W|PF_X;
+		phdr->p_vaddr = (unsigned long) _text;
+		phdr->p_filesz = phdr->p_memsz = _end - _text;
+		phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
+		ehdr->e_phnum++;
+		phdr++;
+	}
+
+	/* Go through all the ranges in mem->ranges[] and prepare phdr */
+	for (i = 0; i < mem->nr_ranges; i++) {
+		mstart = mem->ranges[i].start;
+		mend = mem->ranges[i].end;
+
+		phdr->p_type = PT_LOAD;
+		phdr->p_flags = PF_R|PF_W|PF_X;
+		phdr->p_offset  = mstart;
+
+		phdr->p_paddr = mstart;
+		phdr->p_vaddr = (unsigned long) __va(mstart);
+		phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
+		phdr->p_align = 0;
+		ehdr->e_phnum++;
+		pr_debug("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
+			phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
+			ehdr->e_phnum, phdr->p_offset);
+		phdr++;
+	}
+
+	*addr = buf;
+	*sz = elf_sz;
+	return 0;
+}
diff --git a/kernel/kexec_internal.h b/kernel/kexec_internal.h
new file mode 100644
index 000000000..74da1409c
--- /dev/null
+++ b/kernel/kexec_internal.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LINUX_KEXEC_INTERNAL_H
+#define LINUX_KEXEC_INTERNAL_H
+
+#include <linux/kexec.h>
+
+struct kimage *do_kimage_alloc_init(void);
+int sanity_check_segment_list(struct kimage *image);
+void kimage_free_page_list(struct list_head *list);
+void kimage_free(struct kimage *image);
+int kimage_load_segment(struct kimage *image, struct kexec_segment *segment);
+void kimage_terminate(struct kimage *image);
+int kimage_is_destination_range(struct kimage *image,
+				unsigned long start, unsigned long end);
+
+/*
+ * Whatever is used to serialize accesses to the kexec_crash_image needs to be
+ * NMI safe, as __crash_kexec() can happen during nmi_panic(), so here we use a
+ * "simple" atomic variable that is acquired with a cmpxchg().
+ */
+extern atomic_t __kexec_lock;
+static inline bool kexec_trylock(void)
+{
+	return atomic_cmpxchg_acquire(&__kexec_lock, 0, 1) == 0;
+}
+static inline void kexec_unlock(void)
+{
+	atomic_set_release(&__kexec_lock, 0);
+}
+
+#ifdef CONFIG_KEXEC_FILE
+#include <linux/purgatory.h>
+void kimage_file_post_load_cleanup(struct kimage *image);
+extern char kexec_purgatory[];
+extern size_t kexec_purgatory_size;
+#else /* CONFIG_KEXEC_FILE */
+static inline void kimage_file_post_load_cleanup(struct kimage *image) { }
+#endif /* CONFIG_KEXEC_FILE */
+#endif /* LINUX_KEXEC_INTERNAL_H */
diff --git a/kernel/kheaders.c b/kernel/kheaders.c
new file mode 100644
index 000000000..42163c9e9
--- /dev/null
+++ b/kernel/kheaders.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Provide kernel headers useful to build tracing programs
+ * such as for running eBPF tracing tools.
+ *
+ * (Borrowed code from kernel/configs.c)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kobject.h>
+#include <linux/init.h>
+
+/*
+ * Define kernel_headers_data and kernel_headers_data_end, within which the
+ * compressed kernel headers are stored. The file is first compressed with xz.
+ */
+
+asm (
+"	.pushsection .rodata, \"a\"		\n"
+"	.global kernel_headers_data		\n"
+"kernel_headers_data:				\n"
+"	.incbin \"kernel/kheaders_data.tar.xz\"	\n"
+"	.global kernel_headers_data_end		\n"
+"kernel_headers_data_end:			\n"
+"	.popsection				\n"
+);
+
+extern char kernel_headers_data[];
+extern char kernel_headers_data_end[];
+
+static ssize_t
+ikheaders_read(struct file *file,  struct kobject *kobj,
+	       struct bin_attribute *bin_attr,
+	       char *buf, loff_t off, size_t len)
+{
+	memcpy(buf, &kernel_headers_data[off], len);
+	return len;
+}
+
+static struct bin_attribute kheaders_attr __ro_after_init = {
+	.attr = {
+		.name = "kheaders.tar.xz",
+		.mode = 0444,
+	},
+	.read = &ikheaders_read,
+};
+
+static int __init ikheaders_init(void)
+{
+	kheaders_attr.size = (kernel_headers_data_end -
+			      kernel_headers_data);
+	return sysfs_create_bin_file(kernel_kobj, &kheaders_attr);
+}
+
+static void __exit ikheaders_cleanup(void)
+{
+	sysfs_remove_bin_file(kernel_kobj, &kheaders_attr);
+}
+
+module_init(ikheaders_init);
+module_exit(ikheaders_cleanup);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Joel Fernandes");
+MODULE_DESCRIPTION("Echo the kernel header artifacts used to build the kernel");
diff --git a/kernel/kmod.c b/kernel/kmod.c
new file mode 100644
index 000000000..b717134eb
--- /dev/null
+++ b/kernel/kmod.c
@@ -0,0 +1,177 @@
+/*
+ * kmod - the kernel module loader
+ */
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/binfmts.h>
+#include <linux/syscalls.h>
+#include <linux/unistd.h>
+#include <linux/kmod.h>
+#include <linux/slab.h>
+#include <linux/completion.h>
+#include <linux/cred.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/workqueue.h>
+#include <linux/security.h>
+#include <linux/mount.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/resource.h>
+#include <linux/notifier.h>
+#include <linux/suspend.h>
+#include <linux/rwsem.h>
+#include <linux/ptrace.h>
+#include <linux/async.h>
+#include <linux/uaccess.h>
+
+#include <trace/events/module.h>
+
+/*
+ * Assuming:
+ *
+ * threads = div64_u64((u64) totalram_pages * (u64) PAGE_SIZE,
+ *		       (u64) THREAD_SIZE * 8UL);
+ *
+ * If you need less than 50 threads would mean we're dealing with systems
+ * smaller than 3200 pages. This assumes you are capable of having ~13M memory,
+ * and this would only be an upper limit, after which the OOM killer would take
+ * effect. Systems like these are very unlikely if modules are enabled.
+ */
+#define MAX_KMOD_CONCURRENT 50
+static atomic_t kmod_concurrent_max = ATOMIC_INIT(MAX_KMOD_CONCURRENT);
+static DECLARE_WAIT_QUEUE_HEAD(kmod_wq);
+
+/*
+ * This is a restriction on having *all* MAX_KMOD_CONCURRENT threads
+ * running at the same time without returning. When this happens we
+ * believe you've somehow ended up with a recursive module dependency
+ * creating a loop.
+ *
+ * We have no option but to fail.
+ *
+ * Userspace should proactively try to detect and prevent these.
+ */
+#define MAX_KMOD_ALL_BUSY_TIMEOUT 5
+
+/*
+	modprobe_path is set via /proc/sys.
+*/
+char modprobe_path[KMOD_PATH_LEN] = CONFIG_MODPROBE_PATH;
+
+static void free_modprobe_argv(struct subprocess_info *info)
+{
+	kfree(info->argv[3]); /* check call_modprobe() */
+	kfree(info->argv);
+}
+
+static int call_modprobe(char *module_name, int wait)
+{
+	struct subprocess_info *info;
+	static char *envp[] = {
+		"HOME=/",
+		"TERM=linux",
+		"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
+		NULL
+	};
+
+	char **argv = kmalloc(sizeof(char *[5]), GFP_KERNEL);
+	if (!argv)
+		goto out;
+
+	module_name = kstrdup(module_name, GFP_KERNEL);
+	if (!module_name)
+		goto free_argv;
+
+	argv[0] = modprobe_path;
+	argv[1] = "-q";
+	argv[2] = "--";
+	argv[3] = module_name;	/* check free_modprobe_argv() */
+	argv[4] = NULL;
+
+	info = call_usermodehelper_setup(modprobe_path, argv, envp, GFP_KERNEL,
+					 NULL, free_modprobe_argv, NULL);
+	if (!info)
+		goto free_module_name;
+
+	return call_usermodehelper_exec(info, wait | UMH_KILLABLE);
+
+free_module_name:
+	kfree(module_name);
+free_argv:
+	kfree(argv);
+out:
+	return -ENOMEM;
+}
+
+/**
+ * __request_module - try to load a kernel module
+ * @wait: wait (or not) for the operation to complete
+ * @fmt: printf style format string for the name of the module
+ * @...: arguments as specified in the format string
+ *
+ * Load a module using the user mode module loader. The function returns
+ * zero on success or a negative errno code or positive exit code from
+ * "modprobe" on failure. Note that a successful module load does not mean
+ * the module did not then unload and exit on an error of its own. Callers
+ * must check that the service they requested is now available not blindly
+ * invoke it.
+ *
+ * If module auto-loading support is disabled then this function
+ * simply returns -ENOENT.
+ */
+int __request_module(bool wait, const char *fmt, ...)
+{
+	va_list args;
+	char module_name[MODULE_NAME_LEN];
+	int ret;
+
+	/*
+	 * We don't allow synchronous module loading from async.  Module
+	 * init may invoke async_synchronize_full() which will end up
+	 * waiting for this task which already is waiting for the module
+	 * loading to complete, leading to a deadlock.
+	 */
+	WARN_ON_ONCE(wait && current_is_async());
+
+	if (!modprobe_path[0])
+		return -ENOENT;
+
+	va_start(args, fmt);
+	ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args);
+	va_end(args);
+	if (ret >= MODULE_NAME_LEN)
+		return -ENAMETOOLONG;
+
+	ret = security_kernel_module_request(module_name);
+	if (ret)
+		return ret;
+
+	if (atomic_dec_if_positive(&kmod_concurrent_max) < 0) {
+		pr_warn_ratelimited("request_module: kmod_concurrent_max (%u) close to 0 (max_modprobes: %u), for module %s, throttling...",
+				    atomic_read(&kmod_concurrent_max),
+				    MAX_KMOD_CONCURRENT, module_name);
+		ret = wait_event_killable_timeout(kmod_wq,
+						  atomic_dec_if_positive(&kmod_concurrent_max) >= 0,
+						  MAX_KMOD_ALL_BUSY_TIMEOUT * HZ);
+		if (!ret) {
+			pr_warn_ratelimited("request_module: modprobe %s cannot be processed, kmod busy with %d threads for more than %d seconds now",
+					    module_name, MAX_KMOD_CONCURRENT, MAX_KMOD_ALL_BUSY_TIMEOUT);
+			return -ETIME;
+		} else if (ret == -ERESTARTSYS) {
+			pr_warn_ratelimited("request_module: sigkill sent for modprobe %s, giving up", module_name);
+			return ret;
+		}
+	}
+
+	trace_module_request(module_name, wait, _RET_IP_);
+
+	ret = call_modprobe(module_name, wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC);
+
+	atomic_inc(&kmod_concurrent_max);
+	wake_up(&kmod_wq);
+
+	return ret;
+}
+EXPORT_SYMBOL(__request_module);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
new file mode 100644
index 000000000..dbfddfa86
--- /dev/null
+++ b/kernel/kprobes.c
@@ -0,0 +1,3042 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Kernel Probes (KProbes)
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ *
+ * 2002-Oct	Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
+ *		Probes initial implementation (includes suggestions from
+ *		Rusty Russell).
+ * 2004-Aug	Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
+ *		hlists and exceptions notifier as suggested by Andi Kleen.
+ * 2004-July	Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
+ *		interface to access function arguments.
+ * 2004-Sep	Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
+ *		exceptions notifier to be first on the priority list.
+ * 2005-May	Hien Nguyen <hien@us.ibm.com>, Jim Keniston
+ *		<jkenisto@us.ibm.com> and Prasanna S Panchamukhi
+ *		<prasanna@in.ibm.com> added function-return probes.
+ */
+
+#define pr_fmt(fmt) "kprobes: " fmt
+
+#include <linux/kprobes.h>
+#include <linux/hash.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/stddef.h>
+#include <linux/export.h>
+#include <linux/moduleloader.h>
+#include <linux/kallsyms.h>
+#include <linux/freezer.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/sysctl.h>
+#include <linux/kdebug.h>
+#include <linux/memory.h>
+#include <linux/ftrace.h>
+#include <linux/cpu.h>
+#include <linux/jump_label.h>
+#include <linux/static_call.h>
+#include <linux/perf_event.h>
+
+#include <asm/sections.h>
+#include <asm/cacheflush.h>
+#include <asm/errno.h>
+#include <linux/uaccess.h>
+
+#define KPROBE_HASH_BITS 6
+#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
+
+#if !defined(CONFIG_OPTPROBES) || !defined(CONFIG_SYSCTL)
+#define kprobe_sysctls_init() do { } while (0)
+#endif
+
+static int kprobes_initialized;
+/* kprobe_table can be accessed by
+ * - Normal hlist traversal and RCU add/del under 'kprobe_mutex' is held.
+ * Or
+ * - RCU hlist traversal under disabling preempt (breakpoint handlers)
+ */
+static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
+
+/* NOTE: change this value only with 'kprobe_mutex' held */
+static bool kprobes_all_disarmed;
+
+/* This protects 'kprobe_table' and 'optimizing_list' */
+static DEFINE_MUTEX(kprobe_mutex);
+static DEFINE_PER_CPU(struct kprobe *, kprobe_instance);
+
+kprobe_opcode_t * __weak kprobe_lookup_name(const char *name,
+					unsigned int __unused)
+{
+	return ((kprobe_opcode_t *)(kallsyms_lookup_name(name)));
+}
+
+/*
+ * Blacklist -- list of 'struct kprobe_blacklist_entry' to store info where
+ * kprobes can not probe.
+ */
+static LIST_HEAD(kprobe_blacklist);
+
+#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
+/*
+ * 'kprobe::ainsn.insn' points to the copy of the instruction to be
+ * single-stepped. x86_64, POWER4 and above have no-exec support and
+ * stepping on the instruction on a vmalloced/kmalloced/data page
+ * is a recipe for disaster
+ */
+struct kprobe_insn_page {
+	struct list_head list;
+	kprobe_opcode_t *insns;		/* Page of instruction slots */
+	struct kprobe_insn_cache *cache;
+	int nused;
+	int ngarbage;
+	char slot_used[];
+};
+
+#define KPROBE_INSN_PAGE_SIZE(slots)			\
+	(offsetof(struct kprobe_insn_page, slot_used) +	\
+	 (sizeof(char) * (slots)))
+
+static int slots_per_page(struct kprobe_insn_cache *c)
+{
+	return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
+}
+
+enum kprobe_slot_state {
+	SLOT_CLEAN = 0,
+	SLOT_DIRTY = 1,
+	SLOT_USED = 2,
+};
+
+void __weak *alloc_insn_page(void)
+{
+	/*
+	 * Use module_alloc() so this page is within +/- 2GB of where the
+	 * kernel image and loaded module images reside. This is required
+	 * for most of the architectures.
+	 * (e.g. x86-64 needs this to handle the %rip-relative fixups.)
+	 */
+	return module_alloc(PAGE_SIZE);
+}
+
+static void free_insn_page(void *page)
+{
+	module_memfree(page);
+}
+
+struct kprobe_insn_cache kprobe_insn_slots = {
+	.mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex),
+	.alloc = alloc_insn_page,
+	.free = free_insn_page,
+	.sym = KPROBE_INSN_PAGE_SYM,
+	.pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
+	.insn_size = MAX_INSN_SIZE,
+	.nr_garbage = 0,
+};
+static int collect_garbage_slots(struct kprobe_insn_cache *c);
+
+/**
+ * __get_insn_slot() - Find a slot on an executable page for an instruction.
+ * We allocate an executable page if there's no room on existing ones.
+ */
+kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
+{
+	struct kprobe_insn_page *kip;
+	kprobe_opcode_t *slot = NULL;
+
+	/* Since the slot array is not protected by rcu, we need a mutex */
+	mutex_lock(&c->mutex);
+ retry:
+	rcu_read_lock();
+	list_for_each_entry_rcu(kip, &c->pages, list) {
+		if (kip->nused < slots_per_page(c)) {
+			int i;
+
+			for (i = 0; i < slots_per_page(c); i++) {
+				if (kip->slot_used[i] == SLOT_CLEAN) {
+					kip->slot_used[i] = SLOT_USED;
+					kip->nused++;
+					slot = kip->insns + (i * c->insn_size);
+					rcu_read_unlock();
+					goto out;
+				}
+			}
+			/* kip->nused is broken. Fix it. */
+			kip->nused = slots_per_page(c);
+			WARN_ON(1);
+		}
+	}
+	rcu_read_unlock();
+
+	/* If there are any garbage slots, collect it and try again. */
+	if (c->nr_garbage && collect_garbage_slots(c) == 0)
+		goto retry;
+
+	/* All out of space.  Need to allocate a new page. */
+	kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
+	if (!kip)
+		goto out;
+
+	kip->insns = c->alloc();
+	if (!kip->insns) {
+		kfree(kip);
+		goto out;
+	}
+	INIT_LIST_HEAD(&kip->list);
+	memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
+	kip->slot_used[0] = SLOT_USED;
+	kip->nused = 1;
+	kip->ngarbage = 0;
+	kip->cache = c;
+	list_add_rcu(&kip->list, &c->pages);
+	slot = kip->insns;
+
+	/* Record the perf ksymbol register event after adding the page */
+	perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, (unsigned long)kip->insns,
+			   PAGE_SIZE, false, c->sym);
+out:
+	mutex_unlock(&c->mutex);
+	return slot;
+}
+
+/* Return true if all garbages are collected, otherwise false. */
+static bool collect_one_slot(struct kprobe_insn_page *kip, int idx)
+{
+	kip->slot_used[idx] = SLOT_CLEAN;
+	kip->nused--;
+	if (kip->nused == 0) {
+		/*
+		 * Page is no longer in use.  Free it unless
+		 * it's the last one.  We keep the last one
+		 * so as not to have to set it up again the
+		 * next time somebody inserts a probe.
+		 */
+		if (!list_is_singular(&kip->list)) {
+			/*
+			 * Record perf ksymbol unregister event before removing
+			 * the page.
+			 */
+			perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
+					   (unsigned long)kip->insns, PAGE_SIZE, true,
+					   kip->cache->sym);
+			list_del_rcu(&kip->list);
+			synchronize_rcu();
+			kip->cache->free(kip->insns);
+			kfree(kip);
+		}
+		return true;
+	}
+	return false;
+}
+
+static int collect_garbage_slots(struct kprobe_insn_cache *c)
+{
+	struct kprobe_insn_page *kip, *next;
+
+	/* Ensure no-one is interrupted on the garbages */
+	synchronize_rcu();
+
+	list_for_each_entry_safe(kip, next, &c->pages, list) {
+		int i;
+
+		if (kip->ngarbage == 0)
+			continue;
+		kip->ngarbage = 0;	/* we will collect all garbages */
+		for (i = 0; i < slots_per_page(c); i++) {
+			if (kip->slot_used[i] == SLOT_DIRTY && collect_one_slot(kip, i))
+				break;
+		}
+	}
+	c->nr_garbage = 0;
+	return 0;
+}
+
+void __free_insn_slot(struct kprobe_insn_cache *c,
+		      kprobe_opcode_t *slot, int dirty)
+{
+	struct kprobe_insn_page *kip;
+	long idx;
+
+	mutex_lock(&c->mutex);
+	rcu_read_lock();
+	list_for_each_entry_rcu(kip, &c->pages, list) {
+		idx = ((long)slot - (long)kip->insns) /
+			(c->insn_size * sizeof(kprobe_opcode_t));
+		if (idx >= 0 && idx < slots_per_page(c))
+			goto out;
+	}
+	/* Could not find this slot. */
+	WARN_ON(1);
+	kip = NULL;
+out:
+	rcu_read_unlock();
+	/* Mark and sweep: this may sleep */
+	if (kip) {
+		/* Check double free */
+		WARN_ON(kip->slot_used[idx] != SLOT_USED);
+		if (dirty) {
+			kip->slot_used[idx] = SLOT_DIRTY;
+			kip->ngarbage++;
+			if (++c->nr_garbage > slots_per_page(c))
+				collect_garbage_slots(c);
+		} else {
+			collect_one_slot(kip, idx);
+		}
+	}
+	mutex_unlock(&c->mutex);
+}
+
+/*
+ * Check given address is on the page of kprobe instruction slots.
+ * This will be used for checking whether the address on a stack
+ * is on a text area or not.
+ */
+bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr)
+{
+	struct kprobe_insn_page *kip;
+	bool ret = false;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(kip, &c->pages, list) {
+		if (addr >= (unsigned long)kip->insns &&
+		    addr < (unsigned long)kip->insns + PAGE_SIZE) {
+			ret = true;
+			break;
+		}
+	}
+	rcu_read_unlock();
+
+	return ret;
+}
+
+int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
+			     unsigned long *value, char *type, char *sym)
+{
+	struct kprobe_insn_page *kip;
+	int ret = -ERANGE;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(kip, &c->pages, list) {
+		if ((*symnum)--)
+			continue;
+		strscpy(sym, c->sym, KSYM_NAME_LEN);
+		*type = 't';
+		*value = (unsigned long)kip->insns;
+		ret = 0;
+		break;
+	}
+	rcu_read_unlock();
+
+	return ret;
+}
+
+#ifdef CONFIG_OPTPROBES
+void __weak *alloc_optinsn_page(void)
+{
+	return alloc_insn_page();
+}
+
+void __weak free_optinsn_page(void *page)
+{
+	free_insn_page(page);
+}
+
+/* For optimized_kprobe buffer */
+struct kprobe_insn_cache kprobe_optinsn_slots = {
+	.mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
+	.alloc = alloc_optinsn_page,
+	.free = free_optinsn_page,
+	.sym = KPROBE_OPTINSN_PAGE_SYM,
+	.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
+	/* .insn_size is initialized later */
+	.nr_garbage = 0,
+};
+#endif
+#endif
+
+/* We have preemption disabled.. so it is safe to use __ versions */
+static inline void set_kprobe_instance(struct kprobe *kp)
+{
+	__this_cpu_write(kprobe_instance, kp);
+}
+
+static inline void reset_kprobe_instance(void)
+{
+	__this_cpu_write(kprobe_instance, NULL);
+}
+
+/*
+ * This routine is called either:
+ *	- under the 'kprobe_mutex' - during kprobe_[un]register().
+ *				OR
+ *	- with preemption disabled - from architecture specific code.
+ */
+struct kprobe *get_kprobe(void *addr)
+{
+	struct hlist_head *head;
+	struct kprobe *p;
+
+	head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
+	hlist_for_each_entry_rcu(p, head, hlist,
+				 lockdep_is_held(&kprobe_mutex)) {
+		if (p->addr == addr)
+			return p;
+	}
+
+	return NULL;
+}
+NOKPROBE_SYMBOL(get_kprobe);
+
+static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
+
+/* Return true if 'p' is an aggregator */
+static inline bool kprobe_aggrprobe(struct kprobe *p)
+{
+	return p->pre_handler == aggr_pre_handler;
+}
+
+/* Return true if 'p' is unused */
+static inline bool kprobe_unused(struct kprobe *p)
+{
+	return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
+	       list_empty(&p->list);
+}
+
+/* Keep all fields in the kprobe consistent. */
+static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
+{
+	memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
+	memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
+}
+
+#ifdef CONFIG_OPTPROBES
+/* NOTE: This is protected by 'kprobe_mutex'. */
+static bool kprobes_allow_optimization;
+
+/*
+ * Call all 'kprobe::pre_handler' on the list, but ignores its return value.
+ * This must be called from arch-dep optimized caller.
+ */
+void opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+	struct kprobe *kp;
+
+	list_for_each_entry_rcu(kp, &p->list, list) {
+		if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
+			set_kprobe_instance(kp);
+			kp->pre_handler(kp, regs);
+		}
+		reset_kprobe_instance();
+	}
+}
+NOKPROBE_SYMBOL(opt_pre_handler);
+
+/* Free optimized instructions and optimized_kprobe */
+static void free_aggr_kprobe(struct kprobe *p)
+{
+	struct optimized_kprobe *op;
+
+	op = container_of(p, struct optimized_kprobe, kp);
+	arch_remove_optimized_kprobe(op);
+	arch_remove_kprobe(p);
+	kfree(op);
+}
+
+/* Return true if the kprobe is ready for optimization. */
+static inline int kprobe_optready(struct kprobe *p)
+{
+	struct optimized_kprobe *op;
+
+	if (kprobe_aggrprobe(p)) {
+		op = container_of(p, struct optimized_kprobe, kp);
+		return arch_prepared_optinsn(&op->optinsn);
+	}
+
+	return 0;
+}
+
+/* Return true if the kprobe is disarmed. Note: p must be on hash list */
+bool kprobe_disarmed(struct kprobe *p)
+{
+	struct optimized_kprobe *op;
+
+	/* If kprobe is not aggr/opt probe, just return kprobe is disabled */
+	if (!kprobe_aggrprobe(p))
+		return kprobe_disabled(p);
+
+	op = container_of(p, struct optimized_kprobe, kp);
+
+	return kprobe_disabled(p) && list_empty(&op->list);
+}
+
+/* Return true if the probe is queued on (un)optimizing lists */
+static bool kprobe_queued(struct kprobe *p)
+{
+	struct optimized_kprobe *op;
+
+	if (kprobe_aggrprobe(p)) {
+		op = container_of(p, struct optimized_kprobe, kp);
+		if (!list_empty(&op->list))
+			return true;
+	}
+	return false;
+}
+
+/*
+ * Return an optimized kprobe whose optimizing code replaces
+ * instructions including 'addr' (exclude breakpoint).
+ */
+static struct kprobe *get_optimized_kprobe(kprobe_opcode_t *addr)
+{
+	int i;
+	struct kprobe *p = NULL;
+	struct optimized_kprobe *op;
+
+	/* Don't check i == 0, since that is a breakpoint case. */
+	for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH / sizeof(kprobe_opcode_t); i++)
+		p = get_kprobe(addr - i);
+
+	if (p && kprobe_optready(p)) {
+		op = container_of(p, struct optimized_kprobe, kp);
+		if (arch_within_optimized_kprobe(op, addr))
+			return p;
+	}
+
+	return NULL;
+}
+
+/* Optimization staging list, protected by 'kprobe_mutex' */
+static LIST_HEAD(optimizing_list);
+static LIST_HEAD(unoptimizing_list);
+static LIST_HEAD(freeing_list);
+
+static void kprobe_optimizer(struct work_struct *work);
+static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
+#define OPTIMIZE_DELAY 5
+
+/*
+ * Optimize (replace a breakpoint with a jump) kprobes listed on
+ * 'optimizing_list'.
+ */
+static void do_optimize_kprobes(void)
+{
+	lockdep_assert_held(&text_mutex);
+	/*
+	 * The optimization/unoptimization refers 'online_cpus' via
+	 * stop_machine() and cpu-hotplug modifies the 'online_cpus'.
+	 * And same time, 'text_mutex' will be held in cpu-hotplug and here.
+	 * This combination can cause a deadlock (cpu-hotplug tries to lock
+	 * 'text_mutex' but stop_machine() can not be done because
+	 * the 'online_cpus' has been changed)
+	 * To avoid this deadlock, caller must have locked cpu-hotplug
+	 * for preventing cpu-hotplug outside of 'text_mutex' locking.
+	 */
+	lockdep_assert_cpus_held();
+
+	/* Optimization never be done when disarmed */
+	if (kprobes_all_disarmed || !kprobes_allow_optimization ||
+	    list_empty(&optimizing_list))
+		return;
+
+	arch_optimize_kprobes(&optimizing_list);
+}
+
+/*
+ * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
+ * if need) kprobes listed on 'unoptimizing_list'.
+ */
+static void do_unoptimize_kprobes(void)
+{
+	struct optimized_kprobe *op, *tmp;
+
+	lockdep_assert_held(&text_mutex);
+	/* See comment in do_optimize_kprobes() */
+	lockdep_assert_cpus_held();
+
+	if (!list_empty(&unoptimizing_list))
+		arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);
+
+	/* Loop on 'freeing_list' for disarming and removing from kprobe hash list */
+	list_for_each_entry_safe(op, tmp, &freeing_list, list) {
+		/* Switching from detour code to origin */
+		op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+		/* Disarm probes if marked disabled and not gone */
+		if (kprobe_disabled(&op->kp) && !kprobe_gone(&op->kp))
+			arch_disarm_kprobe(&op->kp);
+		if (kprobe_unused(&op->kp)) {
+			/*
+			 * Remove unused probes from hash list. After waiting
+			 * for synchronization, these probes are reclaimed.
+			 * (reclaiming is done by do_free_cleaned_kprobes().)
+			 */
+			hlist_del_rcu(&op->kp.hlist);
+		} else
+			list_del_init(&op->list);
+	}
+}
+
+/* Reclaim all kprobes on the 'freeing_list' */
+static void do_free_cleaned_kprobes(void)
+{
+	struct optimized_kprobe *op, *tmp;
+
+	list_for_each_entry_safe(op, tmp, &freeing_list, list) {
+		list_del_init(&op->list);
+		if (WARN_ON_ONCE(!kprobe_unused(&op->kp))) {
+			/*
+			 * This must not happen, but if there is a kprobe
+			 * still in use, keep it on kprobes hash list.
+			 */
+			continue;
+		}
+		free_aggr_kprobe(&op->kp);
+	}
+}
+
+/* Start optimizer after OPTIMIZE_DELAY passed */
+static void kick_kprobe_optimizer(void)
+{
+	schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
+}
+
+/* Kprobe jump optimizer */
+static void kprobe_optimizer(struct work_struct *work)
+{
+	mutex_lock(&kprobe_mutex);
+	cpus_read_lock();
+	mutex_lock(&text_mutex);
+
+	/*
+	 * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
+	 * kprobes before waiting for quiesence period.
+	 */
+	do_unoptimize_kprobes();
+
+	/*
+	 * Step 2: Wait for quiesence period to ensure all potentially
+	 * preempted tasks to have normally scheduled. Because optprobe
+	 * may modify multiple instructions, there is a chance that Nth
+	 * instruction is preempted. In that case, such tasks can return
+	 * to 2nd-Nth byte of jump instruction. This wait is for avoiding it.
+	 * Note that on non-preemptive kernel, this is transparently converted
+	 * to synchronoze_sched() to wait for all interrupts to have completed.
+	 */
+	synchronize_rcu_tasks();
+
+	/* Step 3: Optimize kprobes after quiesence period */
+	do_optimize_kprobes();
+
+	/* Step 4: Free cleaned kprobes after quiesence period */
+	do_free_cleaned_kprobes();
+
+	mutex_unlock(&text_mutex);
+	cpus_read_unlock();
+
+	/* Step 5: Kick optimizer again if needed */
+	if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
+		kick_kprobe_optimizer();
+
+	mutex_unlock(&kprobe_mutex);
+}
+
+/* Wait for completing optimization and unoptimization */
+void wait_for_kprobe_optimizer(void)
+{
+	mutex_lock(&kprobe_mutex);
+
+	while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) {
+		mutex_unlock(&kprobe_mutex);
+
+		/* This will also make 'optimizing_work' execute immmediately */
+		flush_delayed_work(&optimizing_work);
+		/* 'optimizing_work' might not have been queued yet, relax */
+		cpu_relax();
+
+		mutex_lock(&kprobe_mutex);
+	}
+
+	mutex_unlock(&kprobe_mutex);
+}
+
+bool optprobe_queued_unopt(struct optimized_kprobe *op)
+{
+	struct optimized_kprobe *_op;
+
+	list_for_each_entry(_op, &unoptimizing_list, list) {
+		if (op == _op)
+			return true;
+	}
+
+	return false;
+}
+
+/* Optimize kprobe if p is ready to be optimized */
+static void optimize_kprobe(struct kprobe *p)
+{
+	struct optimized_kprobe *op;
+
+	/* Check if the kprobe is disabled or not ready for optimization. */
+	if (!kprobe_optready(p) || !kprobes_allow_optimization ||
+	    (kprobe_disabled(p) || kprobes_all_disarmed))
+		return;
+
+	/* kprobes with 'post_handler' can not be optimized */
+	if (p->post_handler)
+		return;
+
+	op = container_of(p, struct optimized_kprobe, kp);
+
+	/* Check there is no other kprobes at the optimized instructions */
+	if (arch_check_optimized_kprobe(op) < 0)
+		return;
+
+	/* Check if it is already optimized. */
+	if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) {
+		if (optprobe_queued_unopt(op)) {
+			/* This is under unoptimizing. Just dequeue the probe */
+			list_del_init(&op->list);
+		}
+		return;
+	}
+	op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
+
+	/*
+	 * On the 'unoptimizing_list' and 'optimizing_list',
+	 * 'op' must have OPTIMIZED flag
+	 */
+	if (WARN_ON_ONCE(!list_empty(&op->list)))
+		return;
+
+	list_add(&op->list, &optimizing_list);
+	kick_kprobe_optimizer();
+}
+
+/* Short cut to direct unoptimizing */
+static void force_unoptimize_kprobe(struct optimized_kprobe *op)
+{
+	lockdep_assert_cpus_held();
+	arch_unoptimize_kprobe(op);
+	op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+}
+
+/* Unoptimize a kprobe if p is optimized */
+static void unoptimize_kprobe(struct kprobe *p, bool force)
+{
+	struct optimized_kprobe *op;
+
+	if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
+		return; /* This is not an optprobe nor optimized */
+
+	op = container_of(p, struct optimized_kprobe, kp);
+	if (!kprobe_optimized(p))
+		return;
+
+	if (!list_empty(&op->list)) {
+		if (optprobe_queued_unopt(op)) {
+			/* Queued in unoptimizing queue */
+			if (force) {
+				/*
+				 * Forcibly unoptimize the kprobe here, and queue it
+				 * in the freeing list for release afterwards.
+				 */
+				force_unoptimize_kprobe(op);
+				list_move(&op->list, &freeing_list);
+			}
+		} else {
+			/* Dequeue from the optimizing queue */
+			list_del_init(&op->list);
+			op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+		}
+		return;
+	}
+
+	/* Optimized kprobe case */
+	if (force) {
+		/* Forcibly update the code: this is a special case */
+		force_unoptimize_kprobe(op);
+	} else {
+		list_add(&op->list, &unoptimizing_list);
+		kick_kprobe_optimizer();
+	}
+}
+
+/* Cancel unoptimizing for reusing */
+static int reuse_unused_kprobe(struct kprobe *ap)
+{
+	struct optimized_kprobe *op;
+
+	/*
+	 * Unused kprobe MUST be on the way of delayed unoptimizing (means
+	 * there is still a relative jump) and disabled.
+	 */
+	op = container_of(ap, struct optimized_kprobe, kp);
+	WARN_ON_ONCE(list_empty(&op->list));
+	/* Enable the probe again */
+	ap->flags &= ~KPROBE_FLAG_DISABLED;
+	/* Optimize it again. (remove from 'op->list') */
+	if (!kprobe_optready(ap))
+		return -EINVAL;
+
+	optimize_kprobe(ap);
+	return 0;
+}
+
+/* Remove optimized instructions */
+static void kill_optimized_kprobe(struct kprobe *p)
+{
+	struct optimized_kprobe *op;
+
+	op = container_of(p, struct optimized_kprobe, kp);
+	if (!list_empty(&op->list))
+		/* Dequeue from the (un)optimization queue */
+		list_del_init(&op->list);
+	op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
+
+	if (kprobe_unused(p)) {
+		/*
+		 * Unused kprobe is on unoptimizing or freeing list. We move it
+		 * to freeing_list and let the kprobe_optimizer() remove it from
+		 * the kprobe hash list and free it.
+		 */
+		if (optprobe_queued_unopt(op))
+			list_move(&op->list, &freeing_list);
+	}
+
+	/* Don't touch the code, because it is already freed. */
+	arch_remove_optimized_kprobe(op);
+}
+
+static inline
+void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
+{
+	if (!kprobe_ftrace(p))
+		arch_prepare_optimized_kprobe(op, p);
+}
+
+/* Try to prepare optimized instructions */
+static void prepare_optimized_kprobe(struct kprobe *p)
+{
+	struct optimized_kprobe *op;
+
+	op = container_of(p, struct optimized_kprobe, kp);
+	__prepare_optimized_kprobe(op, p);
+}
+
+/* Allocate new optimized_kprobe and try to prepare optimized instructions. */
+static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
+{
+	struct optimized_kprobe *op;
+
+	op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
+	if (!op)
+		return NULL;
+
+	INIT_LIST_HEAD(&op->list);
+	op->kp.addr = p->addr;
+	__prepare_optimized_kprobe(op, p);
+
+	return &op->kp;
+}
+
+static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
+
+/*
+ * Prepare an optimized_kprobe and optimize it.
+ * NOTE: 'p' must be a normal registered kprobe.
+ */
+static void try_to_optimize_kprobe(struct kprobe *p)
+{
+	struct kprobe *ap;
+	struct optimized_kprobe *op;
+
+	/* Impossible to optimize ftrace-based kprobe. */
+	if (kprobe_ftrace(p))
+		return;
+
+	/* For preparing optimization, jump_label_text_reserved() is called. */
+	cpus_read_lock();
+	jump_label_lock();
+	mutex_lock(&text_mutex);
+
+	ap = alloc_aggr_kprobe(p);
+	if (!ap)
+		goto out;
+
+	op = container_of(ap, struct optimized_kprobe, kp);
+	if (!arch_prepared_optinsn(&op->optinsn)) {
+		/* If failed to setup optimizing, fallback to kprobe. */
+		arch_remove_optimized_kprobe(op);
+		kfree(op);
+		goto out;
+	}
+
+	init_aggr_kprobe(ap, p);
+	optimize_kprobe(ap);	/* This just kicks optimizer thread. */
+
+out:
+	mutex_unlock(&text_mutex);
+	jump_label_unlock();
+	cpus_read_unlock();
+}
+
+static void optimize_all_kprobes(void)
+{
+	struct hlist_head *head;
+	struct kprobe *p;
+	unsigned int i;
+
+	mutex_lock(&kprobe_mutex);
+	/* If optimization is already allowed, just return. */
+	if (kprobes_allow_optimization)
+		goto out;
+
+	cpus_read_lock();
+	kprobes_allow_optimization = true;
+	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+		head = &kprobe_table[i];
+		hlist_for_each_entry(p, head, hlist)
+			if (!kprobe_disabled(p))
+				optimize_kprobe(p);
+	}
+	cpus_read_unlock();
+	pr_info("kprobe jump-optimization is enabled. All kprobes are optimized if possible.\n");
+out:
+	mutex_unlock(&kprobe_mutex);
+}
+
+#ifdef CONFIG_SYSCTL
+static void unoptimize_all_kprobes(void)
+{
+	struct hlist_head *head;
+	struct kprobe *p;
+	unsigned int i;
+
+	mutex_lock(&kprobe_mutex);
+	/* If optimization is already prohibited, just return. */
+	if (!kprobes_allow_optimization) {
+		mutex_unlock(&kprobe_mutex);
+		return;
+	}
+
+	cpus_read_lock();
+	kprobes_allow_optimization = false;
+	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+		head = &kprobe_table[i];
+		hlist_for_each_entry(p, head, hlist) {
+			if (!kprobe_disabled(p))
+				unoptimize_kprobe(p, false);
+		}
+	}
+	cpus_read_unlock();
+	mutex_unlock(&kprobe_mutex);
+
+	/* Wait for unoptimizing completion. */
+	wait_for_kprobe_optimizer();
+	pr_info("kprobe jump-optimization is disabled. All kprobes are based on software breakpoint.\n");
+}
+
+static DEFINE_MUTEX(kprobe_sysctl_mutex);
+static int sysctl_kprobes_optimization;
+static int proc_kprobes_optimization_handler(struct ctl_table *table,
+					     int write, void *buffer,
+					     size_t *length, loff_t *ppos)
+{
+	int ret;
+
+	mutex_lock(&kprobe_sysctl_mutex);
+	sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
+	ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
+
+	if (sysctl_kprobes_optimization)
+		optimize_all_kprobes();
+	else
+		unoptimize_all_kprobes();
+	mutex_unlock(&kprobe_sysctl_mutex);
+
+	return ret;
+}
+
+static struct ctl_table kprobe_sysctls[] = {
+	{
+		.procname	= "kprobes-optimization",
+		.data		= &sysctl_kprobes_optimization,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_kprobes_optimization_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{}
+};
+
+static void __init kprobe_sysctls_init(void)
+{
+	register_sysctl_init("debug", kprobe_sysctls);
+}
+#endif /* CONFIG_SYSCTL */
+
+/* Put a breakpoint for a probe. */
+static void __arm_kprobe(struct kprobe *p)
+{
+	struct kprobe *_p;
+
+	lockdep_assert_held(&text_mutex);
+
+	/* Find the overlapping optimized kprobes. */
+	_p = get_optimized_kprobe(p->addr);
+	if (unlikely(_p))
+		/* Fallback to unoptimized kprobe */
+		unoptimize_kprobe(_p, true);
+
+	arch_arm_kprobe(p);
+	optimize_kprobe(p);	/* Try to optimize (add kprobe to a list) */
+}
+
+/* Remove the breakpoint of a probe. */
+static void __disarm_kprobe(struct kprobe *p, bool reopt)
+{
+	struct kprobe *_p;
+
+	lockdep_assert_held(&text_mutex);
+
+	/* Try to unoptimize */
+	unoptimize_kprobe(p, kprobes_all_disarmed);
+
+	if (!kprobe_queued(p)) {
+		arch_disarm_kprobe(p);
+		/* If another kprobe was blocked, re-optimize it. */
+		_p = get_optimized_kprobe(p->addr);
+		if (unlikely(_p) && reopt)
+			optimize_kprobe(_p);
+	}
+	/*
+	 * TODO: Since unoptimization and real disarming will be done by
+	 * the worker thread, we can not check whether another probe are
+	 * unoptimized because of this probe here. It should be re-optimized
+	 * by the worker thread.
+	 */
+}
+
+#else /* !CONFIG_OPTPROBES */
+
+#define optimize_kprobe(p)			do {} while (0)
+#define unoptimize_kprobe(p, f)			do {} while (0)
+#define kill_optimized_kprobe(p)		do {} while (0)
+#define prepare_optimized_kprobe(p)		do {} while (0)
+#define try_to_optimize_kprobe(p)		do {} while (0)
+#define __arm_kprobe(p)				arch_arm_kprobe(p)
+#define __disarm_kprobe(p, o)			arch_disarm_kprobe(p)
+#define kprobe_disarmed(p)			kprobe_disabled(p)
+#define wait_for_kprobe_optimizer()		do {} while (0)
+
+static int reuse_unused_kprobe(struct kprobe *ap)
+{
+	/*
+	 * If the optimized kprobe is NOT supported, the aggr kprobe is
+	 * released at the same time that the last aggregated kprobe is
+	 * unregistered.
+	 * Thus there should be no chance to reuse unused kprobe.
+	 */
+	WARN_ON_ONCE(1);
+	return -EINVAL;
+}
+
+static void free_aggr_kprobe(struct kprobe *p)
+{
+	arch_remove_kprobe(p);
+	kfree(p);
+}
+
+static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
+{
+	return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
+}
+#endif /* CONFIG_OPTPROBES */
+
+#ifdef CONFIG_KPROBES_ON_FTRACE
+static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
+	.func = kprobe_ftrace_handler,
+	.flags = FTRACE_OPS_FL_SAVE_REGS,
+};
+
+static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = {
+	.func = kprobe_ftrace_handler,
+	.flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
+};
+
+static int kprobe_ipmodify_enabled;
+static int kprobe_ftrace_enabled;
+
+static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
+			       int *cnt)
+{
+	int ret = 0;
+
+	lockdep_assert_held(&kprobe_mutex);
+
+	ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0);
+	if (WARN_ONCE(ret < 0, "Failed to arm kprobe-ftrace at %pS (error %d)\n", p->addr, ret))
+		return ret;
+
+	if (*cnt == 0) {
+		ret = register_ftrace_function(ops);
+		if (WARN(ret < 0, "Failed to register kprobe-ftrace (error %d)\n", ret))
+			goto err_ftrace;
+	}
+
+	(*cnt)++;
+	return ret;
+
+err_ftrace:
+	/*
+	 * At this point, sinec ops is not registered, we should be sefe from
+	 * registering empty filter.
+	 */
+	ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
+	return ret;
+}
+
+static int arm_kprobe_ftrace(struct kprobe *p)
+{
+	bool ipmodify = (p->post_handler != NULL);
+
+	return __arm_kprobe_ftrace(p,
+		ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
+		ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
+}
+
+static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
+				  int *cnt)
+{
+	int ret = 0;
+
+	lockdep_assert_held(&kprobe_mutex);
+
+	if (*cnt == 1) {
+		ret = unregister_ftrace_function(ops);
+		if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (error %d)\n", ret))
+			return ret;
+	}
+
+	(*cnt)--;
+
+	ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
+	WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (error %d)\n",
+		  p->addr, ret);
+	return ret;
+}
+
+static int disarm_kprobe_ftrace(struct kprobe *p)
+{
+	bool ipmodify = (p->post_handler != NULL);
+
+	return __disarm_kprobe_ftrace(p,
+		ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
+		ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
+}
+#else	/* !CONFIG_KPROBES_ON_FTRACE */
+static inline int arm_kprobe_ftrace(struct kprobe *p)
+{
+	return -ENODEV;
+}
+
+static inline int disarm_kprobe_ftrace(struct kprobe *p)
+{
+	return -ENODEV;
+}
+#endif
+
+static int prepare_kprobe(struct kprobe *p)
+{
+	/* Must ensure p->addr is really on ftrace */
+	if (kprobe_ftrace(p))
+		return arch_prepare_kprobe_ftrace(p);
+
+	return arch_prepare_kprobe(p);
+}
+
+static int arm_kprobe(struct kprobe *kp)
+{
+	if (unlikely(kprobe_ftrace(kp)))
+		return arm_kprobe_ftrace(kp);
+
+	cpus_read_lock();
+	mutex_lock(&text_mutex);
+	__arm_kprobe(kp);
+	mutex_unlock(&text_mutex);
+	cpus_read_unlock();
+
+	return 0;
+}
+
+static int disarm_kprobe(struct kprobe *kp, bool reopt)
+{
+	if (unlikely(kprobe_ftrace(kp)))
+		return disarm_kprobe_ftrace(kp);
+
+	cpus_read_lock();
+	mutex_lock(&text_mutex);
+	__disarm_kprobe(kp, reopt);
+	mutex_unlock(&text_mutex);
+	cpus_read_unlock();
+
+	return 0;
+}
+
+/*
+ * Aggregate handlers for multiple kprobes support - these handlers
+ * take care of invoking the individual kprobe handlers on p->list
+ */
+static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+	struct kprobe *kp;
+
+	list_for_each_entry_rcu(kp, &p->list, list) {
+		if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
+			set_kprobe_instance(kp);
+			if (kp->pre_handler(kp, regs))
+				return 1;
+		}
+		reset_kprobe_instance();
+	}
+	return 0;
+}
+NOKPROBE_SYMBOL(aggr_pre_handler);
+
+static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
+			      unsigned long flags)
+{
+	struct kprobe *kp;
+
+	list_for_each_entry_rcu(kp, &p->list, list) {
+		if (kp->post_handler && likely(!kprobe_disabled(kp))) {
+			set_kprobe_instance(kp);
+			kp->post_handler(kp, regs, flags);
+			reset_kprobe_instance();
+		}
+	}
+}
+NOKPROBE_SYMBOL(aggr_post_handler);
+
+/* Walks the list and increments 'nmissed' if 'p' has child probes. */
+void kprobes_inc_nmissed_count(struct kprobe *p)
+{
+	struct kprobe *kp;
+
+	if (!kprobe_aggrprobe(p)) {
+		p->nmissed++;
+	} else {
+		list_for_each_entry_rcu(kp, &p->list, list)
+			kp->nmissed++;
+	}
+}
+NOKPROBE_SYMBOL(kprobes_inc_nmissed_count);
+
+static struct kprobe kprobe_busy = {
+	.addr = (void *) get_kprobe,
+};
+
+void kprobe_busy_begin(void)
+{
+	struct kprobe_ctlblk *kcb;
+
+	preempt_disable();
+	__this_cpu_write(current_kprobe, &kprobe_busy);
+	kcb = get_kprobe_ctlblk();
+	kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+}
+
+void kprobe_busy_end(void)
+{
+	__this_cpu_write(current_kprobe, NULL);
+	preempt_enable();
+}
+
+/* Add the new probe to 'ap->list'. */
+static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
+{
+	if (p->post_handler)
+		unoptimize_kprobe(ap, true);	/* Fall back to normal kprobe */
+
+	list_add_rcu(&p->list, &ap->list);
+	if (p->post_handler && !ap->post_handler)
+		ap->post_handler = aggr_post_handler;
+
+	return 0;
+}
+
+/*
+ * Fill in the required fields of the aggregator kprobe. Replace the
+ * earlier kprobe in the hlist with the aggregator kprobe.
+ */
+static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
+{
+	/* Copy the insn slot of 'p' to 'ap'. */
+	copy_kprobe(p, ap);
+	flush_insn_slot(ap);
+	ap->addr = p->addr;
+	ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
+	ap->pre_handler = aggr_pre_handler;
+	/* We don't care the kprobe which has gone. */
+	if (p->post_handler && !kprobe_gone(p))
+		ap->post_handler = aggr_post_handler;
+
+	INIT_LIST_HEAD(&ap->list);
+	INIT_HLIST_NODE(&ap->hlist);
+
+	list_add_rcu(&p->list, &ap->list);
+	hlist_replace_rcu(&p->hlist, &ap->hlist);
+}
+
+/*
+ * This registers the second or subsequent kprobe at the same address.
+ */
+static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
+{
+	int ret = 0;
+	struct kprobe *ap = orig_p;
+
+	cpus_read_lock();
+
+	/* For preparing optimization, jump_label_text_reserved() is called */
+	jump_label_lock();
+	mutex_lock(&text_mutex);
+
+	if (!kprobe_aggrprobe(orig_p)) {
+		/* If 'orig_p' is not an 'aggr_kprobe', create new one. */
+		ap = alloc_aggr_kprobe(orig_p);
+		if (!ap) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		init_aggr_kprobe(ap, orig_p);
+	} else if (kprobe_unused(ap)) {
+		/* This probe is going to die. Rescue it */
+		ret = reuse_unused_kprobe(ap);
+		if (ret)
+			goto out;
+	}
+
+	if (kprobe_gone(ap)) {
+		/*
+		 * Attempting to insert new probe at the same location that
+		 * had a probe in the module vaddr area which already
+		 * freed. So, the instruction slot has already been
+		 * released. We need a new slot for the new probe.
+		 */
+		ret = arch_prepare_kprobe(ap);
+		if (ret)
+			/*
+			 * Even if fail to allocate new slot, don't need to
+			 * free the 'ap'. It will be used next time, or
+			 * freed by unregister_kprobe().
+			 */
+			goto out;
+
+		/* Prepare optimized instructions if possible. */
+		prepare_optimized_kprobe(ap);
+
+		/*
+		 * Clear gone flag to prevent allocating new slot again, and
+		 * set disabled flag because it is not armed yet.
+		 */
+		ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
+			    | KPROBE_FLAG_DISABLED;
+	}
+
+	/* Copy the insn slot of 'p' to 'ap'. */
+	copy_kprobe(ap, p);
+	ret = add_new_kprobe(ap, p);
+
+out:
+	mutex_unlock(&text_mutex);
+	jump_label_unlock();
+	cpus_read_unlock();
+
+	if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
+		ap->flags &= ~KPROBE_FLAG_DISABLED;
+		if (!kprobes_all_disarmed) {
+			/* Arm the breakpoint again. */
+			ret = arm_kprobe(ap);
+			if (ret) {
+				ap->flags |= KPROBE_FLAG_DISABLED;
+				list_del_rcu(&p->list);
+				synchronize_rcu();
+			}
+		}
+	}
+	return ret;
+}
+
+bool __weak arch_within_kprobe_blacklist(unsigned long addr)
+{
+	/* The '__kprobes' functions and entry code must not be probed. */
+	return addr >= (unsigned long)__kprobes_text_start &&
+	       addr < (unsigned long)__kprobes_text_end;
+}
+
+static bool __within_kprobe_blacklist(unsigned long addr)
+{
+	struct kprobe_blacklist_entry *ent;
+
+	if (arch_within_kprobe_blacklist(addr))
+		return true;
+	/*
+	 * If 'kprobe_blacklist' is defined, check the address and
+	 * reject any probe registration in the prohibited area.
+	 */
+	list_for_each_entry(ent, &kprobe_blacklist, list) {
+		if (addr >= ent->start_addr && addr < ent->end_addr)
+			return true;
+	}
+	return false;
+}
+
+bool within_kprobe_blacklist(unsigned long addr)
+{
+	char symname[KSYM_NAME_LEN], *p;
+
+	if (__within_kprobe_blacklist(addr))
+		return true;
+
+	/* Check if the address is on a suffixed-symbol */
+	if (!lookup_symbol_name(addr, symname)) {
+		p = strchr(symname, '.');
+		if (!p)
+			return false;
+		*p = '\0';
+		addr = (unsigned long)kprobe_lookup_name(symname, 0);
+		if (addr)
+			return __within_kprobe_blacklist(addr);
+	}
+	return false;
+}
+
+/*
+ * arch_adjust_kprobe_addr - adjust the address
+ * @addr: symbol base address
+ * @offset: offset within the symbol
+ * @on_func_entry: was this @addr+@offset on the function entry
+ *
+ * Typically returns @addr + @offset, except for special cases where the
+ * function might be prefixed by a CFI landing pad, in that case any offset
+ * inside the landing pad is mapped to the first 'real' instruction of the
+ * symbol.
+ *
+ * Specifically, for things like IBT/BTI, skip the resp. ENDBR/BTI.C
+ * instruction at +0.
+ */
+kprobe_opcode_t *__weak arch_adjust_kprobe_addr(unsigned long addr,
+						unsigned long offset,
+						bool *on_func_entry)
+{
+	*on_func_entry = !offset;
+	return (kprobe_opcode_t *)(addr + offset);
+}
+
+/*
+ * If 'symbol_name' is specified, look it up and add the 'offset'
+ * to it. This way, we can specify a relative address to a symbol.
+ * This returns encoded errors if it fails to look up symbol or invalid
+ * combination of parameters.
+ */
+static kprobe_opcode_t *
+_kprobe_addr(kprobe_opcode_t *addr, const char *symbol_name,
+	     unsigned long offset, bool *on_func_entry)
+{
+	if ((symbol_name && addr) || (!symbol_name && !addr))
+		goto invalid;
+
+	if (symbol_name) {
+		/*
+		 * Input: @sym + @offset
+		 * Output: @addr + @offset
+		 *
+		 * NOTE: kprobe_lookup_name() does *NOT* fold the offset
+		 *       argument into it's output!
+		 */
+		addr = kprobe_lookup_name(symbol_name, offset);
+		if (!addr)
+			return ERR_PTR(-ENOENT);
+	}
+
+	/*
+	 * So here we have @addr + @offset, displace it into a new
+	 * @addr' + @offset' where @addr' is the symbol start address.
+	 */
+	addr = (void *)addr + offset;
+	if (!kallsyms_lookup_size_offset((unsigned long)addr, NULL, &offset))
+		return ERR_PTR(-ENOENT);
+	addr = (void *)addr - offset;
+
+	/*
+	 * Then ask the architecture to re-combine them, taking care of
+	 * magical function entry details while telling us if this was indeed
+	 * at the start of the function.
+	 */
+	addr = arch_adjust_kprobe_addr((unsigned long)addr, offset, on_func_entry);
+	if (addr)
+		return addr;
+
+invalid:
+	return ERR_PTR(-EINVAL);
+}
+
+static kprobe_opcode_t *kprobe_addr(struct kprobe *p)
+{
+	bool on_func_entry;
+	return _kprobe_addr(p->addr, p->symbol_name, p->offset, &on_func_entry);
+}
+
+/*
+ * Check the 'p' is valid and return the aggregator kprobe
+ * at the same address.
+ */
+static struct kprobe *__get_valid_kprobe(struct kprobe *p)
+{
+	struct kprobe *ap, *list_p;
+
+	lockdep_assert_held(&kprobe_mutex);
+
+	ap = get_kprobe(p->addr);
+	if (unlikely(!ap))
+		return NULL;
+
+	if (p != ap) {
+		list_for_each_entry(list_p, &ap->list, list)
+			if (list_p == p)
+			/* kprobe p is a valid probe */
+				goto valid;
+		return NULL;
+	}
+valid:
+	return ap;
+}
+
+/*
+ * Warn and return error if the kprobe is being re-registered since
+ * there must be a software bug.
+ */
+static inline int warn_kprobe_rereg(struct kprobe *p)
+{
+	int ret = 0;
+
+	mutex_lock(&kprobe_mutex);
+	if (WARN_ON_ONCE(__get_valid_kprobe(p)))
+		ret = -EINVAL;
+	mutex_unlock(&kprobe_mutex);
+
+	return ret;
+}
+
+static int check_ftrace_location(struct kprobe *p)
+{
+	unsigned long addr = (unsigned long)p->addr;
+
+	if (ftrace_location(addr) == addr) {
+#ifdef CONFIG_KPROBES_ON_FTRACE
+		p->flags |= KPROBE_FLAG_FTRACE;
+#else	/* !CONFIG_KPROBES_ON_FTRACE */
+		return -EINVAL;
+#endif
+	}
+	return 0;
+}
+
+static bool is_cfi_preamble_symbol(unsigned long addr)
+{
+	char symbuf[KSYM_NAME_LEN];
+
+	if (lookup_symbol_name(addr, symbuf))
+		return false;
+
+	return str_has_prefix("__cfi_", symbuf) ||
+		str_has_prefix("__pfx_", symbuf);
+}
+
+static int check_kprobe_address_safe(struct kprobe *p,
+				     struct module **probed_mod)
+{
+	int ret;
+
+	ret = check_ftrace_location(p);
+	if (ret)
+		return ret;
+	jump_label_lock();
+	preempt_disable();
+
+	/* Ensure it is not in reserved area nor out of text */
+	if (!(core_kernel_text((unsigned long) p->addr) ||
+	    is_module_text_address((unsigned long) p->addr)) ||
+	    in_gate_area_no_mm((unsigned long) p->addr) ||
+	    within_kprobe_blacklist((unsigned long) p->addr) ||
+	    jump_label_text_reserved(p->addr, p->addr) ||
+	    static_call_text_reserved(p->addr, p->addr) ||
+	    find_bug((unsigned long)p->addr) ||
+	    is_cfi_preamble_symbol((unsigned long)p->addr)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Check if 'p' is probing a module. */
+	*probed_mod = __module_text_address((unsigned long) p->addr);
+	if (*probed_mod) {
+		/*
+		 * We must hold a refcount of the probed module while updating
+		 * its code to prohibit unexpected unloading.
+		 */
+		if (unlikely(!try_module_get(*probed_mod))) {
+			ret = -ENOENT;
+			goto out;
+		}
+
+		/*
+		 * If the module freed '.init.text', we couldn't insert
+		 * kprobes in there.
+		 */
+		if (within_module_init((unsigned long)p->addr, *probed_mod) &&
+		    (*probed_mod)->state != MODULE_STATE_COMING) {
+			module_put(*probed_mod);
+			*probed_mod = NULL;
+			ret = -ENOENT;
+		}
+	}
+out:
+	preempt_enable();
+	jump_label_unlock();
+
+	return ret;
+}
+
+int register_kprobe(struct kprobe *p)
+{
+	int ret;
+	struct kprobe *old_p;
+	struct module *probed_mod;
+	kprobe_opcode_t *addr;
+	bool on_func_entry;
+
+	/* Adjust probe address from symbol */
+	addr = _kprobe_addr(p->addr, p->symbol_name, p->offset, &on_func_entry);
+	if (IS_ERR(addr))
+		return PTR_ERR(addr);
+	p->addr = addr;
+
+	ret = warn_kprobe_rereg(p);
+	if (ret)
+		return ret;
+
+	/* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
+	p->flags &= KPROBE_FLAG_DISABLED;
+	p->nmissed = 0;
+	INIT_LIST_HEAD(&p->list);
+
+	ret = check_kprobe_address_safe(p, &probed_mod);
+	if (ret)
+		return ret;
+
+	mutex_lock(&kprobe_mutex);
+
+	if (on_func_entry)
+		p->flags |= KPROBE_FLAG_ON_FUNC_ENTRY;
+
+	old_p = get_kprobe(p->addr);
+	if (old_p) {
+		/* Since this may unoptimize 'old_p', locking 'text_mutex'. */
+		ret = register_aggr_kprobe(old_p, p);
+		goto out;
+	}
+
+	cpus_read_lock();
+	/* Prevent text modification */
+	mutex_lock(&text_mutex);
+	ret = prepare_kprobe(p);
+	mutex_unlock(&text_mutex);
+	cpus_read_unlock();
+	if (ret)
+		goto out;
+
+	INIT_HLIST_NODE(&p->hlist);
+	hlist_add_head_rcu(&p->hlist,
+		       &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
+
+	if (!kprobes_all_disarmed && !kprobe_disabled(p)) {
+		ret = arm_kprobe(p);
+		if (ret) {
+			hlist_del_rcu(&p->hlist);
+			synchronize_rcu();
+			goto out;
+		}
+	}
+
+	/* Try to optimize kprobe */
+	try_to_optimize_kprobe(p);
+out:
+	mutex_unlock(&kprobe_mutex);
+
+	if (probed_mod)
+		module_put(probed_mod);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_kprobe);
+
+/* Check if all probes on the 'ap' are disabled. */
+static bool aggr_kprobe_disabled(struct kprobe *ap)
+{
+	struct kprobe *kp;
+
+	lockdep_assert_held(&kprobe_mutex);
+
+	list_for_each_entry(kp, &ap->list, list)
+		if (!kprobe_disabled(kp))
+			/*
+			 * Since there is an active probe on the list,
+			 * we can't disable this 'ap'.
+			 */
+			return false;
+
+	return true;
+}
+
+static struct kprobe *__disable_kprobe(struct kprobe *p)
+{
+	struct kprobe *orig_p;
+	int ret;
+
+	lockdep_assert_held(&kprobe_mutex);
+
+	/* Get an original kprobe for return */
+	orig_p = __get_valid_kprobe(p);
+	if (unlikely(orig_p == NULL))
+		return ERR_PTR(-EINVAL);
+
+	if (!kprobe_disabled(p)) {
+		/* Disable probe if it is a child probe */
+		if (p != orig_p)
+			p->flags |= KPROBE_FLAG_DISABLED;
+
+		/* Try to disarm and disable this/parent probe */
+		if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
+			/*
+			 * Don't be lazy here.  Even if 'kprobes_all_disarmed'
+			 * is false, 'orig_p' might not have been armed yet.
+			 * Note arm_all_kprobes() __tries__ to arm all kprobes
+			 * on the best effort basis.
+			 */
+			if (!kprobes_all_disarmed && !kprobe_disabled(orig_p)) {
+				ret = disarm_kprobe(orig_p, true);
+				if (ret) {
+					p->flags &= ~KPROBE_FLAG_DISABLED;
+					return ERR_PTR(ret);
+				}
+			}
+			orig_p->flags |= KPROBE_FLAG_DISABLED;
+		}
+	}
+
+	return orig_p;
+}
+
+/*
+ * Unregister a kprobe without a scheduler synchronization.
+ */
+static int __unregister_kprobe_top(struct kprobe *p)
+{
+	struct kprobe *ap, *list_p;
+
+	/* Disable kprobe. This will disarm it if needed. */
+	ap = __disable_kprobe(p);
+	if (IS_ERR(ap))
+		return PTR_ERR(ap);
+
+	if (ap == p)
+		/*
+		 * This probe is an independent(and non-optimized) kprobe
+		 * (not an aggrprobe). Remove from the hash list.
+		 */
+		goto disarmed;
+
+	/* Following process expects this probe is an aggrprobe */
+	WARN_ON(!kprobe_aggrprobe(ap));
+
+	if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
+		/*
+		 * !disarmed could be happen if the probe is under delayed
+		 * unoptimizing.
+		 */
+		goto disarmed;
+	else {
+		/* If disabling probe has special handlers, update aggrprobe */
+		if (p->post_handler && !kprobe_gone(p)) {
+			list_for_each_entry(list_p, &ap->list, list) {
+				if ((list_p != p) && (list_p->post_handler))
+					goto noclean;
+			}
+			/*
+			 * For the kprobe-on-ftrace case, we keep the
+			 * post_handler setting to identify this aggrprobe
+			 * armed with kprobe_ipmodify_ops.
+			 */
+			if (!kprobe_ftrace(ap))
+				ap->post_handler = NULL;
+		}
+noclean:
+		/*
+		 * Remove from the aggrprobe: this path will do nothing in
+		 * __unregister_kprobe_bottom().
+		 */
+		list_del_rcu(&p->list);
+		if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
+			/*
+			 * Try to optimize this probe again, because post
+			 * handler may have been changed.
+			 */
+			optimize_kprobe(ap);
+	}
+	return 0;
+
+disarmed:
+	hlist_del_rcu(&ap->hlist);
+	return 0;
+}
+
+static void __unregister_kprobe_bottom(struct kprobe *p)
+{
+	struct kprobe *ap;
+
+	if (list_empty(&p->list))
+		/* This is an independent kprobe */
+		arch_remove_kprobe(p);
+	else if (list_is_singular(&p->list)) {
+		/* This is the last child of an aggrprobe */
+		ap = list_entry(p->list.next, struct kprobe, list);
+		list_del(&p->list);
+		free_aggr_kprobe(ap);
+	}
+	/* Otherwise, do nothing. */
+}
+
+int register_kprobes(struct kprobe **kps, int num)
+{
+	int i, ret = 0;
+
+	if (num <= 0)
+		return -EINVAL;
+	for (i = 0; i < num; i++) {
+		ret = register_kprobe(kps[i]);
+		if (ret < 0) {
+			if (i > 0)
+				unregister_kprobes(kps, i);
+			break;
+		}
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_kprobes);
+
+void unregister_kprobe(struct kprobe *p)
+{
+	unregister_kprobes(&p, 1);
+}
+EXPORT_SYMBOL_GPL(unregister_kprobe);
+
+void unregister_kprobes(struct kprobe **kps, int num)
+{
+	int i;
+
+	if (num <= 0)
+		return;
+	mutex_lock(&kprobe_mutex);
+	for (i = 0; i < num; i++)
+		if (__unregister_kprobe_top(kps[i]) < 0)
+			kps[i]->addr = NULL;
+	mutex_unlock(&kprobe_mutex);
+
+	synchronize_rcu();
+	for (i = 0; i < num; i++)
+		if (kps[i]->addr)
+			__unregister_kprobe_bottom(kps[i]);
+}
+EXPORT_SYMBOL_GPL(unregister_kprobes);
+
+int __weak kprobe_exceptions_notify(struct notifier_block *self,
+					unsigned long val, void *data)
+{
+	return NOTIFY_DONE;
+}
+NOKPROBE_SYMBOL(kprobe_exceptions_notify);
+
+static struct notifier_block kprobe_exceptions_nb = {
+	.notifier_call = kprobe_exceptions_notify,
+	.priority = 0x7fffffff /* we need to be notified first */
+};
+
+#ifdef CONFIG_KRETPROBES
+
+#if !defined(CONFIG_KRETPROBE_ON_RETHOOK)
+static void free_rp_inst_rcu(struct rcu_head *head)
+{
+	struct kretprobe_instance *ri = container_of(head, struct kretprobe_instance, rcu);
+
+	if (refcount_dec_and_test(&ri->rph->ref))
+		kfree(ri->rph);
+	kfree(ri);
+}
+NOKPROBE_SYMBOL(free_rp_inst_rcu);
+
+static void recycle_rp_inst(struct kretprobe_instance *ri)
+{
+	struct kretprobe *rp = get_kretprobe(ri);
+
+	if (likely(rp))
+		freelist_add(&ri->freelist, &rp->freelist);
+	else
+		call_rcu(&ri->rcu, free_rp_inst_rcu);
+}
+NOKPROBE_SYMBOL(recycle_rp_inst);
+
+/*
+ * This function is called from delayed_put_task_struct() when a task is
+ * dead and cleaned up to recycle any kretprobe instances associated with
+ * this task. These left over instances represent probed functions that
+ * have been called but will never return.
+ */
+void kprobe_flush_task(struct task_struct *tk)
+{
+	struct kretprobe_instance *ri;
+	struct llist_node *node;
+
+	/* Early boot, not yet initialized. */
+	if (unlikely(!kprobes_initialized))
+		return;
+
+	kprobe_busy_begin();
+
+	node = __llist_del_all(&tk->kretprobe_instances);
+	while (node) {
+		ri = container_of(node, struct kretprobe_instance, llist);
+		node = node->next;
+
+		recycle_rp_inst(ri);
+	}
+
+	kprobe_busy_end();
+}
+NOKPROBE_SYMBOL(kprobe_flush_task);
+
+static inline void free_rp_inst(struct kretprobe *rp)
+{
+	struct kretprobe_instance *ri;
+	struct freelist_node *node;
+	int count = 0;
+
+	node = rp->freelist.head;
+	while (node) {
+		ri = container_of(node, struct kretprobe_instance, freelist);
+		node = node->next;
+
+		kfree(ri);
+		count++;
+	}
+
+	if (refcount_sub_and_test(count, &rp->rph->ref)) {
+		kfree(rp->rph);
+		rp->rph = NULL;
+	}
+}
+
+/* This assumes the 'tsk' is the current task or the is not running. */
+static kprobe_opcode_t *__kretprobe_find_ret_addr(struct task_struct *tsk,
+						  struct llist_node **cur)
+{
+	struct kretprobe_instance *ri = NULL;
+	struct llist_node *node = *cur;
+
+	if (!node)
+		node = tsk->kretprobe_instances.first;
+	else
+		node = node->next;
+
+	while (node) {
+		ri = container_of(node, struct kretprobe_instance, llist);
+		if (ri->ret_addr != kretprobe_trampoline_addr()) {
+			*cur = node;
+			return ri->ret_addr;
+		}
+		node = node->next;
+	}
+	return NULL;
+}
+NOKPROBE_SYMBOL(__kretprobe_find_ret_addr);
+
+/**
+ * kretprobe_find_ret_addr -- Find correct return address modified by kretprobe
+ * @tsk: Target task
+ * @fp: A frame pointer
+ * @cur: a storage of the loop cursor llist_node pointer for next call
+ *
+ * Find the correct return address modified by a kretprobe on @tsk in unsigned
+ * long type. If it finds the return address, this returns that address value,
+ * or this returns 0.
+ * The @tsk must be 'current' or a task which is not running. @fp is a hint
+ * to get the currect return address - which is compared with the
+ * kretprobe_instance::fp field. The @cur is a loop cursor for searching the
+ * kretprobe return addresses on the @tsk. The '*@cur' should be NULL at the
+ * first call, but '@cur' itself must NOT NULL.
+ */
+unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
+				      struct llist_node **cur)
+{
+	struct kretprobe_instance *ri = NULL;
+	kprobe_opcode_t *ret;
+
+	if (WARN_ON_ONCE(!cur))
+		return 0;
+
+	do {
+		ret = __kretprobe_find_ret_addr(tsk, cur);
+		if (!ret)
+			break;
+		ri = container_of(*cur, struct kretprobe_instance, llist);
+	} while (ri->fp != fp);
+
+	return (unsigned long)ret;
+}
+NOKPROBE_SYMBOL(kretprobe_find_ret_addr);
+
+void __weak arch_kretprobe_fixup_return(struct pt_regs *regs,
+					kprobe_opcode_t *correct_ret_addr)
+{
+	/*
+	 * Do nothing by default. Please fill this to update the fake return
+	 * address on the stack with the correct one on each arch if possible.
+	 */
+}
+
+unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
+					     void *frame_pointer)
+{
+	kprobe_opcode_t *correct_ret_addr = NULL;
+	struct kretprobe_instance *ri = NULL;
+	struct llist_node *first, *node = NULL;
+	struct kretprobe *rp;
+
+	/* Find correct address and all nodes for this frame. */
+	correct_ret_addr = __kretprobe_find_ret_addr(current, &node);
+	if (!correct_ret_addr) {
+		pr_err("kretprobe: Return address not found, not execute handler. Maybe there is a bug in the kernel.\n");
+		BUG_ON(1);
+	}
+
+	/*
+	 * Set the return address as the instruction pointer, because if the
+	 * user handler calls stack_trace_save_regs() with this 'regs',
+	 * the stack trace will start from the instruction pointer.
+	 */
+	instruction_pointer_set(regs, (unsigned long)correct_ret_addr);
+
+	/* Run the user handler of the nodes. */
+	first = current->kretprobe_instances.first;
+	while (first) {
+		ri = container_of(first, struct kretprobe_instance, llist);
+
+		if (WARN_ON_ONCE(ri->fp != frame_pointer))
+			break;
+
+		rp = get_kretprobe(ri);
+		if (rp && rp->handler) {
+			struct kprobe *prev = kprobe_running();
+
+			__this_cpu_write(current_kprobe, &rp->kp);
+			ri->ret_addr = correct_ret_addr;
+			rp->handler(ri, regs);
+			__this_cpu_write(current_kprobe, prev);
+		}
+		if (first == node)
+			break;
+
+		first = first->next;
+	}
+
+	arch_kretprobe_fixup_return(regs, correct_ret_addr);
+
+	/* Unlink all nodes for this frame. */
+	first = current->kretprobe_instances.first;
+	current->kretprobe_instances.first = node->next;
+	node->next = NULL;
+
+	/* Recycle free instances. */
+	while (first) {
+		ri = container_of(first, struct kretprobe_instance, llist);
+		first = first->next;
+
+		recycle_rp_inst(ri);
+	}
+
+	return (unsigned long)correct_ret_addr;
+}
+NOKPROBE_SYMBOL(__kretprobe_trampoline_handler)
+
+/*
+ * This kprobe pre_handler is registered with every kretprobe. When probe
+ * hits it will set up the return probe.
+ */
+static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
+{
+	struct kretprobe *rp = container_of(p, struct kretprobe, kp);
+	struct kretprobe_instance *ri;
+	struct freelist_node *fn;
+
+	fn = freelist_try_get(&rp->freelist);
+	if (!fn) {
+		rp->nmissed++;
+		return 0;
+	}
+
+	ri = container_of(fn, struct kretprobe_instance, freelist);
+
+	if (rp->entry_handler && rp->entry_handler(ri, regs)) {
+		freelist_add(&ri->freelist, &rp->freelist);
+		return 0;
+	}
+
+	arch_prepare_kretprobe(ri, regs);
+
+	__llist_add(&ri->llist, &current->kretprobe_instances);
+
+	return 0;
+}
+NOKPROBE_SYMBOL(pre_handler_kretprobe);
+#else /* CONFIG_KRETPROBE_ON_RETHOOK */
+/*
+ * This kprobe pre_handler is registered with every kretprobe. When probe
+ * hits it will set up the return probe.
+ */
+static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
+{
+	struct kretprobe *rp = container_of(p, struct kretprobe, kp);
+	struct kretprobe_instance *ri;
+	struct rethook_node *rhn;
+
+	rhn = rethook_try_get(rp->rh);
+	if (!rhn) {
+		rp->nmissed++;
+		return 0;
+	}
+
+	ri = container_of(rhn, struct kretprobe_instance, node);
+
+	if (rp->entry_handler && rp->entry_handler(ri, regs))
+		rethook_recycle(rhn);
+	else
+		rethook_hook(rhn, regs, kprobe_ftrace(p));
+
+	return 0;
+}
+NOKPROBE_SYMBOL(pre_handler_kretprobe);
+
+static void kretprobe_rethook_handler(struct rethook_node *rh, void *data,
+				      struct pt_regs *regs)
+{
+	struct kretprobe *rp = (struct kretprobe *)data;
+	struct kretprobe_instance *ri;
+	struct kprobe_ctlblk *kcb;
+
+	/* The data must NOT be null. This means rethook data structure is broken. */
+	if (WARN_ON_ONCE(!data) || !rp->handler)
+		return;
+
+	__this_cpu_write(current_kprobe, &rp->kp);
+	kcb = get_kprobe_ctlblk();
+	kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+
+	ri = container_of(rh, struct kretprobe_instance, node);
+	rp->handler(ri, regs);
+
+	__this_cpu_write(current_kprobe, NULL);
+}
+NOKPROBE_SYMBOL(kretprobe_rethook_handler);
+
+#endif /* !CONFIG_KRETPROBE_ON_RETHOOK */
+
+/**
+ * kprobe_on_func_entry() -- check whether given address is function entry
+ * @addr: Target address
+ * @sym:  Target symbol name
+ * @offset: The offset from the symbol or the address
+ *
+ * This checks whether the given @addr+@offset or @sym+@offset is on the
+ * function entry address or not.
+ * This returns 0 if it is the function entry, or -EINVAL if it is not.
+ * And also it returns -ENOENT if it fails the symbol or address lookup.
+ * Caller must pass @addr or @sym (either one must be NULL), or this
+ * returns -EINVAL.
+ */
+int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset)
+{
+	bool on_func_entry;
+	kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset, &on_func_entry);
+
+	if (IS_ERR(kp_addr))
+		return PTR_ERR(kp_addr);
+
+	if (!on_func_entry)
+		return -EINVAL;
+
+	return 0;
+}
+
+int register_kretprobe(struct kretprobe *rp)
+{
+	int ret;
+	struct kretprobe_instance *inst;
+	int i;
+	void *addr;
+
+	ret = kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset);
+	if (ret)
+		return ret;
+
+	/* If only 'rp->kp.addr' is specified, check reregistering kprobes */
+	if (rp->kp.addr && warn_kprobe_rereg(&rp->kp))
+		return -EINVAL;
+
+	if (kretprobe_blacklist_size) {
+		addr = kprobe_addr(&rp->kp);
+		if (IS_ERR(addr))
+			return PTR_ERR(addr);
+
+		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
+			if (kretprobe_blacklist[i].addr == addr)
+				return -EINVAL;
+		}
+	}
+
+	if (rp->data_size > KRETPROBE_MAX_DATA_SIZE)
+		return -E2BIG;
+
+	rp->kp.pre_handler = pre_handler_kretprobe;
+	rp->kp.post_handler = NULL;
+
+	/* Pre-allocate memory for max kretprobe instances */
+	if (rp->maxactive <= 0)
+		rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
+
+#ifdef CONFIG_KRETPROBE_ON_RETHOOK
+	rp->rh = rethook_alloc((void *)rp, kretprobe_rethook_handler);
+	if (!rp->rh)
+		return -ENOMEM;
+
+	for (i = 0; i < rp->maxactive; i++) {
+		inst = kzalloc(sizeof(struct kretprobe_instance) +
+			       rp->data_size, GFP_KERNEL);
+		if (inst == NULL) {
+			rethook_free(rp->rh);
+			rp->rh = NULL;
+			return -ENOMEM;
+		}
+		rethook_add_node(rp->rh, &inst->node);
+	}
+	rp->nmissed = 0;
+	/* Establish function entry probe point */
+	ret = register_kprobe(&rp->kp);
+	if (ret != 0) {
+		rethook_free(rp->rh);
+		rp->rh = NULL;
+	}
+#else	/* !CONFIG_KRETPROBE_ON_RETHOOK */
+	rp->freelist.head = NULL;
+	rp->rph = kzalloc(sizeof(struct kretprobe_holder), GFP_KERNEL);
+	if (!rp->rph)
+		return -ENOMEM;
+
+	rcu_assign_pointer(rp->rph->rp, rp);
+	for (i = 0; i < rp->maxactive; i++) {
+		inst = kzalloc(sizeof(struct kretprobe_instance) +
+			       rp->data_size, GFP_KERNEL);
+		if (inst == NULL) {
+			refcount_set(&rp->rph->ref, i);
+			free_rp_inst(rp);
+			return -ENOMEM;
+		}
+		inst->rph = rp->rph;
+		freelist_add(&inst->freelist, &rp->freelist);
+	}
+	refcount_set(&rp->rph->ref, i);
+
+	rp->nmissed = 0;
+	/* Establish function entry probe point */
+	ret = register_kprobe(&rp->kp);
+	if (ret != 0)
+		free_rp_inst(rp);
+#endif
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_kretprobe);
+
+int register_kretprobes(struct kretprobe **rps, int num)
+{
+	int ret = 0, i;
+
+	if (num <= 0)
+		return -EINVAL;
+	for (i = 0; i < num; i++) {
+		ret = register_kretprobe(rps[i]);
+		if (ret < 0) {
+			if (i > 0)
+				unregister_kretprobes(rps, i);
+			break;
+		}
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_kretprobes);
+
+void unregister_kretprobe(struct kretprobe *rp)
+{
+	unregister_kretprobes(&rp, 1);
+}
+EXPORT_SYMBOL_GPL(unregister_kretprobe);
+
+void unregister_kretprobes(struct kretprobe **rps, int num)
+{
+	int i;
+
+	if (num <= 0)
+		return;
+	mutex_lock(&kprobe_mutex);
+	for (i = 0; i < num; i++) {
+		if (__unregister_kprobe_top(&rps[i]->kp) < 0)
+			rps[i]->kp.addr = NULL;
+#ifdef CONFIG_KRETPROBE_ON_RETHOOK
+		rethook_free(rps[i]->rh);
+#else
+		rcu_assign_pointer(rps[i]->rph->rp, NULL);
+#endif
+	}
+	mutex_unlock(&kprobe_mutex);
+
+	synchronize_rcu();
+	for (i = 0; i < num; i++) {
+		if (rps[i]->kp.addr) {
+			__unregister_kprobe_bottom(&rps[i]->kp);
+#ifndef CONFIG_KRETPROBE_ON_RETHOOK
+			free_rp_inst(rps[i]);
+#endif
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(unregister_kretprobes);
+
+#else /* CONFIG_KRETPROBES */
+int register_kretprobe(struct kretprobe *rp)
+{
+	return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL_GPL(register_kretprobe);
+
+int register_kretprobes(struct kretprobe **rps, int num)
+{
+	return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL_GPL(register_kretprobes);
+
+void unregister_kretprobe(struct kretprobe *rp)
+{
+}
+EXPORT_SYMBOL_GPL(unregister_kretprobe);
+
+void unregister_kretprobes(struct kretprobe **rps, int num)
+{
+}
+EXPORT_SYMBOL_GPL(unregister_kretprobes);
+
+static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
+{
+	return 0;
+}
+NOKPROBE_SYMBOL(pre_handler_kretprobe);
+
+#endif /* CONFIG_KRETPROBES */
+
+/* Set the kprobe gone and remove its instruction buffer. */
+static void kill_kprobe(struct kprobe *p)
+{
+	struct kprobe *kp;
+
+	lockdep_assert_held(&kprobe_mutex);
+
+	/*
+	 * The module is going away. We should disarm the kprobe which
+	 * is using ftrace, because ftrace framework is still available at
+	 * 'MODULE_STATE_GOING' notification.
+	 */
+	if (kprobe_ftrace(p) && !kprobe_disabled(p) && !kprobes_all_disarmed)
+		disarm_kprobe_ftrace(p);
+
+	p->flags |= KPROBE_FLAG_GONE;
+	if (kprobe_aggrprobe(p)) {
+		/*
+		 * If this is an aggr_kprobe, we have to list all the
+		 * chained probes and mark them GONE.
+		 */
+		list_for_each_entry(kp, &p->list, list)
+			kp->flags |= KPROBE_FLAG_GONE;
+		p->post_handler = NULL;
+		kill_optimized_kprobe(p);
+	}
+	/*
+	 * Here, we can remove insn_slot safely, because no thread calls
+	 * the original probed function (which will be freed soon) any more.
+	 */
+	arch_remove_kprobe(p);
+}
+
+/* Disable one kprobe */
+int disable_kprobe(struct kprobe *kp)
+{
+	int ret = 0;
+	struct kprobe *p;
+
+	mutex_lock(&kprobe_mutex);
+
+	/* Disable this kprobe */
+	p = __disable_kprobe(kp);
+	if (IS_ERR(p))
+		ret = PTR_ERR(p);
+
+	mutex_unlock(&kprobe_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(disable_kprobe);
+
+/* Enable one kprobe */
+int enable_kprobe(struct kprobe *kp)
+{
+	int ret = 0;
+	struct kprobe *p;
+
+	mutex_lock(&kprobe_mutex);
+
+	/* Check whether specified probe is valid. */
+	p = __get_valid_kprobe(kp);
+	if (unlikely(p == NULL)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (kprobe_gone(kp)) {
+		/* This kprobe has gone, we couldn't enable it. */
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (p != kp)
+		kp->flags &= ~KPROBE_FLAG_DISABLED;
+
+	if (!kprobes_all_disarmed && kprobe_disabled(p)) {
+		p->flags &= ~KPROBE_FLAG_DISABLED;
+		ret = arm_kprobe(p);
+		if (ret) {
+			p->flags |= KPROBE_FLAG_DISABLED;
+			if (p != kp)
+				kp->flags |= KPROBE_FLAG_DISABLED;
+		}
+	}
+out:
+	mutex_unlock(&kprobe_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(enable_kprobe);
+
+/* Caller must NOT call this in usual path. This is only for critical case */
+void dump_kprobe(struct kprobe *kp)
+{
+	pr_err("Dump kprobe:\n.symbol_name = %s, .offset = %x, .addr = %pS\n",
+	       kp->symbol_name, kp->offset, kp->addr);
+}
+NOKPROBE_SYMBOL(dump_kprobe);
+
+int kprobe_add_ksym_blacklist(unsigned long entry)
+{
+	struct kprobe_blacklist_entry *ent;
+	unsigned long offset = 0, size = 0;
+
+	if (!kernel_text_address(entry) ||
+	    !kallsyms_lookup_size_offset(entry, &size, &offset))
+		return -EINVAL;
+
+	ent = kmalloc(sizeof(*ent), GFP_KERNEL);
+	if (!ent)
+		return -ENOMEM;
+	ent->start_addr = entry;
+	ent->end_addr = entry + size;
+	INIT_LIST_HEAD(&ent->list);
+	list_add_tail(&ent->list, &kprobe_blacklist);
+
+	return (int)size;
+}
+
+/* Add all symbols in given area into kprobe blacklist */
+int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
+{
+	unsigned long entry;
+	int ret = 0;
+
+	for (entry = start; entry < end; entry += ret) {
+		ret = kprobe_add_ksym_blacklist(entry);
+		if (ret < 0)
+			return ret;
+		if (ret == 0)	/* In case of alias symbol */
+			ret = 1;
+	}
+	return 0;
+}
+
+/* Remove all symbols in given area from kprobe blacklist */
+static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
+{
+	struct kprobe_blacklist_entry *ent, *n;
+
+	list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
+		if (ent->start_addr < start || ent->start_addr >= end)
+			continue;
+		list_del(&ent->list);
+		kfree(ent);
+	}
+}
+
+static void kprobe_remove_ksym_blacklist(unsigned long entry)
+{
+	kprobe_remove_area_blacklist(entry, entry + 1);
+}
+
+int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
+				   char *type, char *sym)
+{
+	return -ERANGE;
+}
+
+int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
+		       char *sym)
+{
+#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
+	if (!kprobe_cache_get_kallsym(&kprobe_insn_slots, &symnum, value, type, sym))
+		return 0;
+#ifdef CONFIG_OPTPROBES
+	if (!kprobe_cache_get_kallsym(&kprobe_optinsn_slots, &symnum, value, type, sym))
+		return 0;
+#endif
+#endif
+	if (!arch_kprobe_get_kallsym(&symnum, value, type, sym))
+		return 0;
+	return -ERANGE;
+}
+
+int __init __weak arch_populate_kprobe_blacklist(void)
+{
+	return 0;
+}
+
+/*
+ * Lookup and populate the kprobe_blacklist.
+ *
+ * Unlike the kretprobe blacklist, we'll need to determine
+ * the range of addresses that belong to the said functions,
+ * since a kprobe need not necessarily be at the beginning
+ * of a function.
+ */
+static int __init populate_kprobe_blacklist(unsigned long *start,
+					     unsigned long *end)
+{
+	unsigned long entry;
+	unsigned long *iter;
+	int ret;
+
+	for (iter = start; iter < end; iter++) {
+		entry = (unsigned long)dereference_symbol_descriptor((void *)*iter);
+		ret = kprobe_add_ksym_blacklist(entry);
+		if (ret == -EINVAL)
+			continue;
+		if (ret < 0)
+			return ret;
+	}
+
+	/* Symbols in '__kprobes_text' are blacklisted */
+	ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start,
+					(unsigned long)__kprobes_text_end);
+	if (ret)
+		return ret;
+
+	/* Symbols in 'noinstr' section are blacklisted */
+	ret = kprobe_add_area_blacklist((unsigned long)__noinstr_text_start,
+					(unsigned long)__noinstr_text_end);
+
+	return ret ? : arch_populate_kprobe_blacklist();
+}
+
+static void add_module_kprobe_blacklist(struct module *mod)
+{
+	unsigned long start, end;
+	int i;
+
+	if (mod->kprobe_blacklist) {
+		for (i = 0; i < mod->num_kprobe_blacklist; i++)
+			kprobe_add_ksym_blacklist(mod->kprobe_blacklist[i]);
+	}
+
+	start = (unsigned long)mod->kprobes_text_start;
+	if (start) {
+		end = start + mod->kprobes_text_size;
+		kprobe_add_area_blacklist(start, end);
+	}
+
+	start = (unsigned long)mod->noinstr_text_start;
+	if (start) {
+		end = start + mod->noinstr_text_size;
+		kprobe_add_area_blacklist(start, end);
+	}
+}
+
+static void remove_module_kprobe_blacklist(struct module *mod)
+{
+	unsigned long start, end;
+	int i;
+
+	if (mod->kprobe_blacklist) {
+		for (i = 0; i < mod->num_kprobe_blacklist; i++)
+			kprobe_remove_ksym_blacklist(mod->kprobe_blacklist[i]);
+	}
+
+	start = (unsigned long)mod->kprobes_text_start;
+	if (start) {
+		end = start + mod->kprobes_text_size;
+		kprobe_remove_area_blacklist(start, end);
+	}
+
+	start = (unsigned long)mod->noinstr_text_start;
+	if (start) {
+		end = start + mod->noinstr_text_size;
+		kprobe_remove_area_blacklist(start, end);
+	}
+}
+
+/* Module notifier call back, checking kprobes on the module */
+static int kprobes_module_callback(struct notifier_block *nb,
+				   unsigned long val, void *data)
+{
+	struct module *mod = data;
+	struct hlist_head *head;
+	struct kprobe *p;
+	unsigned int i;
+	int checkcore = (val == MODULE_STATE_GOING);
+
+	if (val == MODULE_STATE_COMING) {
+		mutex_lock(&kprobe_mutex);
+		add_module_kprobe_blacklist(mod);
+		mutex_unlock(&kprobe_mutex);
+	}
+	if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
+		return NOTIFY_DONE;
+
+	/*
+	 * When 'MODULE_STATE_GOING' was notified, both of module '.text' and
+	 * '.init.text' sections would be freed. When 'MODULE_STATE_LIVE' was
+	 * notified, only '.init.text' section would be freed. We need to
+	 * disable kprobes which have been inserted in the sections.
+	 */
+	mutex_lock(&kprobe_mutex);
+	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+		head = &kprobe_table[i];
+		hlist_for_each_entry(p, head, hlist)
+			if (within_module_init((unsigned long)p->addr, mod) ||
+			    (checkcore &&
+			     within_module_core((unsigned long)p->addr, mod))) {
+				/*
+				 * The vaddr this probe is installed will soon
+				 * be vfreed buy not synced to disk. Hence,
+				 * disarming the breakpoint isn't needed.
+				 *
+				 * Note, this will also move any optimized probes
+				 * that are pending to be removed from their
+				 * corresponding lists to the 'freeing_list' and
+				 * will not be touched by the delayed
+				 * kprobe_optimizer() work handler.
+				 */
+				kill_kprobe(p);
+			}
+	}
+	if (val == MODULE_STATE_GOING)
+		remove_module_kprobe_blacklist(mod);
+	mutex_unlock(&kprobe_mutex);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block kprobe_module_nb = {
+	.notifier_call = kprobes_module_callback,
+	.priority = 0
+};
+
+void kprobe_free_init_mem(void)
+{
+	void *start = (void *)(&__init_begin);
+	void *end = (void *)(&__init_end);
+	struct hlist_head *head;
+	struct kprobe *p;
+	int i;
+
+	mutex_lock(&kprobe_mutex);
+
+	/* Kill all kprobes on initmem because the target code has been freed. */
+	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+		head = &kprobe_table[i];
+		hlist_for_each_entry(p, head, hlist) {
+			if (start <= (void *)p->addr && (void *)p->addr < end)
+				kill_kprobe(p);
+		}
+	}
+
+	mutex_unlock(&kprobe_mutex);
+}
+
+static int __init init_kprobes(void)
+{
+	int i, err = 0;
+
+	/* FIXME allocate the probe table, currently defined statically */
+	/* initialize all list heads */
+	for (i = 0; i < KPROBE_TABLE_SIZE; i++)
+		INIT_HLIST_HEAD(&kprobe_table[i]);
+
+	err = populate_kprobe_blacklist(__start_kprobe_blacklist,
+					__stop_kprobe_blacklist);
+	if (err)
+		pr_err("Failed to populate blacklist (error %d), kprobes not restricted, be careful using them!\n", err);
+
+	if (kretprobe_blacklist_size) {
+		/* lookup the function address from its name */
+		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
+			kretprobe_blacklist[i].addr =
+				kprobe_lookup_name(kretprobe_blacklist[i].name, 0);
+			if (!kretprobe_blacklist[i].addr)
+				pr_err("Failed to lookup symbol '%s' for kretprobe blacklist. Maybe the target function is removed or renamed.\n",
+				       kretprobe_blacklist[i].name);
+		}
+	}
+
+	/* By default, kprobes are armed */
+	kprobes_all_disarmed = false;
+
+#if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT)
+	/* Init 'kprobe_optinsn_slots' for allocation */
+	kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
+#endif
+
+	err = arch_init_kprobes();
+	if (!err)
+		err = register_die_notifier(&kprobe_exceptions_nb);
+	if (!err)
+		err = register_module_notifier(&kprobe_module_nb);
+
+	kprobes_initialized = (err == 0);
+	kprobe_sysctls_init();
+	return err;
+}
+early_initcall(init_kprobes);
+
+#if defined(CONFIG_OPTPROBES)
+static int __init init_optprobes(void)
+{
+	/*
+	 * Enable kprobe optimization - this kicks the optimizer which
+	 * depends on synchronize_rcu_tasks() and ksoftirqd, that is
+	 * not spawned in early initcall. So delay the optimization.
+	 */
+	optimize_all_kprobes();
+
+	return 0;
+}
+subsys_initcall(init_optprobes);
+#endif
+
+#ifdef CONFIG_DEBUG_FS
+static void report_probe(struct seq_file *pi, struct kprobe *p,
+		const char *sym, int offset, char *modname, struct kprobe *pp)
+{
+	char *kprobe_type;
+	void *addr = p->addr;
+
+	if (p->pre_handler == pre_handler_kretprobe)
+		kprobe_type = "r";
+	else
+		kprobe_type = "k";
+
+	if (!kallsyms_show_value(pi->file->f_cred))
+		addr = NULL;
+
+	if (sym)
+		seq_printf(pi, "%px  %s  %s+0x%x  %s ",
+			addr, kprobe_type, sym, offset,
+			(modname ? modname : " "));
+	else	/* try to use %pS */
+		seq_printf(pi, "%px  %s  %pS ",
+			addr, kprobe_type, p->addr);
+
+	if (!pp)
+		pp = p;
+	seq_printf(pi, "%s%s%s%s\n",
+		(kprobe_gone(p) ? "[GONE]" : ""),
+		((kprobe_disabled(p) && !kprobe_gone(p)) ?  "[DISABLED]" : ""),
+		(kprobe_optimized(pp) ? "[OPTIMIZED]" : ""),
+		(kprobe_ftrace(pp) ? "[FTRACE]" : ""));
+}
+
+static void *kprobe_seq_start(struct seq_file *f, loff_t *pos)
+{
+	return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
+}
+
+static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
+{
+	(*pos)++;
+	if (*pos >= KPROBE_TABLE_SIZE)
+		return NULL;
+	return pos;
+}
+
+static void kprobe_seq_stop(struct seq_file *f, void *v)
+{
+	/* Nothing to do */
+}
+
+static int show_kprobe_addr(struct seq_file *pi, void *v)
+{
+	struct hlist_head *head;
+	struct kprobe *p, *kp;
+	const char *sym = NULL;
+	unsigned int i = *(loff_t *) v;
+	unsigned long offset = 0;
+	char *modname, namebuf[KSYM_NAME_LEN];
+
+	head = &kprobe_table[i];
+	preempt_disable();
+	hlist_for_each_entry_rcu(p, head, hlist) {
+		sym = kallsyms_lookup((unsigned long)p->addr, NULL,
+					&offset, &modname, namebuf);
+		if (kprobe_aggrprobe(p)) {
+			list_for_each_entry_rcu(kp, &p->list, list)
+				report_probe(pi, kp, sym, offset, modname, p);
+		} else
+			report_probe(pi, p, sym, offset, modname, NULL);
+	}
+	preempt_enable();
+	return 0;
+}
+
+static const struct seq_operations kprobes_sops = {
+	.start = kprobe_seq_start,
+	.next  = kprobe_seq_next,
+	.stop  = kprobe_seq_stop,
+	.show  = show_kprobe_addr
+};
+
+DEFINE_SEQ_ATTRIBUTE(kprobes);
+
+/* kprobes/blacklist -- shows which functions can not be probed */
+static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
+{
+	mutex_lock(&kprobe_mutex);
+	return seq_list_start(&kprobe_blacklist, *pos);
+}
+
+static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return seq_list_next(v, &kprobe_blacklist, pos);
+}
+
+static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
+{
+	struct kprobe_blacklist_entry *ent =
+		list_entry(v, struct kprobe_blacklist_entry, list);
+
+	/*
+	 * If '/proc/kallsyms' is not showing kernel address, we won't
+	 * show them here either.
+	 */
+	if (!kallsyms_show_value(m->file->f_cred))
+		seq_printf(m, "0x%px-0x%px\t%ps\n", NULL, NULL,
+			   (void *)ent->start_addr);
+	else
+		seq_printf(m, "0x%px-0x%px\t%ps\n", (void *)ent->start_addr,
+			   (void *)ent->end_addr, (void *)ent->start_addr);
+	return 0;
+}
+
+static void kprobe_blacklist_seq_stop(struct seq_file *f, void *v)
+{
+	mutex_unlock(&kprobe_mutex);
+}
+
+static const struct seq_operations kprobe_blacklist_sops = {
+	.start = kprobe_blacklist_seq_start,
+	.next  = kprobe_blacklist_seq_next,
+	.stop  = kprobe_blacklist_seq_stop,
+	.show  = kprobe_blacklist_seq_show,
+};
+DEFINE_SEQ_ATTRIBUTE(kprobe_blacklist);
+
+static int arm_all_kprobes(void)
+{
+	struct hlist_head *head;
+	struct kprobe *p;
+	unsigned int i, total = 0, errors = 0;
+	int err, ret = 0;
+
+	mutex_lock(&kprobe_mutex);
+
+	/* If kprobes are armed, just return */
+	if (!kprobes_all_disarmed)
+		goto already_enabled;
+
+	/*
+	 * optimize_kprobe() called by arm_kprobe() checks
+	 * kprobes_all_disarmed, so set kprobes_all_disarmed before
+	 * arm_kprobe.
+	 */
+	kprobes_all_disarmed = false;
+	/* Arming kprobes doesn't optimize kprobe itself */
+	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+		head = &kprobe_table[i];
+		/* Arm all kprobes on a best-effort basis */
+		hlist_for_each_entry(p, head, hlist) {
+			if (!kprobe_disabled(p)) {
+				err = arm_kprobe(p);
+				if (err)  {
+					errors++;
+					ret = err;
+				}
+				total++;
+			}
+		}
+	}
+
+	if (errors)
+		pr_warn("Kprobes globally enabled, but failed to enable %d out of %d probes. Please check which kprobes are kept disabled via debugfs.\n",
+			errors, total);
+	else
+		pr_info("Kprobes globally enabled\n");
+
+already_enabled:
+	mutex_unlock(&kprobe_mutex);
+	return ret;
+}
+
+static int disarm_all_kprobes(void)
+{
+	struct hlist_head *head;
+	struct kprobe *p;
+	unsigned int i, total = 0, errors = 0;
+	int err, ret = 0;
+
+	mutex_lock(&kprobe_mutex);
+
+	/* If kprobes are already disarmed, just return */
+	if (kprobes_all_disarmed) {
+		mutex_unlock(&kprobe_mutex);
+		return 0;
+	}
+
+	kprobes_all_disarmed = true;
+
+	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+		head = &kprobe_table[i];
+		/* Disarm all kprobes on a best-effort basis */
+		hlist_for_each_entry(p, head, hlist) {
+			if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) {
+				err = disarm_kprobe(p, false);
+				if (err) {
+					errors++;
+					ret = err;
+				}
+				total++;
+			}
+		}
+	}
+
+	if (errors)
+		pr_warn("Kprobes globally disabled, but failed to disable %d out of %d probes. Please check which kprobes are kept enabled via debugfs.\n",
+			errors, total);
+	else
+		pr_info("Kprobes globally disabled\n");
+
+	mutex_unlock(&kprobe_mutex);
+
+	/* Wait for disarming all kprobes by optimizer */
+	wait_for_kprobe_optimizer();
+
+	return ret;
+}
+
+/*
+ * XXX: The debugfs bool file interface doesn't allow for callbacks
+ * when the bool state is switched. We can reuse that facility when
+ * available
+ */
+static ssize_t read_enabled_file_bool(struct file *file,
+	       char __user *user_buf, size_t count, loff_t *ppos)
+{
+	char buf[3];
+
+	if (!kprobes_all_disarmed)
+		buf[0] = '1';
+	else
+		buf[0] = '0';
+	buf[1] = '\n';
+	buf[2] = 0x00;
+	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
+}
+
+static ssize_t write_enabled_file_bool(struct file *file,
+	       const char __user *user_buf, size_t count, loff_t *ppos)
+{
+	bool enable;
+	int ret;
+
+	ret = kstrtobool_from_user(user_buf, count, &enable);
+	if (ret)
+		return ret;
+
+	ret = enable ? arm_all_kprobes() : disarm_all_kprobes();
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static const struct file_operations fops_kp = {
+	.read =         read_enabled_file_bool,
+	.write =        write_enabled_file_bool,
+	.llseek =	default_llseek,
+};
+
+static int __init debugfs_kprobe_init(void)
+{
+	struct dentry *dir;
+
+	dir = debugfs_create_dir("kprobes", NULL);
+
+	debugfs_create_file("list", 0400, dir, NULL, &kprobes_fops);
+
+	debugfs_create_file("enabled", 0600, dir, NULL, &fops_kp);
+
+	debugfs_create_file("blacklist", 0400, dir, NULL,
+			    &kprobe_blacklist_fops);
+
+	return 0;
+}
+
+late_initcall(debugfs_kprobe_init);
+#endif /* CONFIG_DEBUG_FS */
diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
new file mode 100644
index 000000000..65dba9076
--- /dev/null
+++ b/kernel/ksysfs.c
@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
+ * 		     are not related to any other subsystem
+ *
+ * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ */
+
+#include <linux/kobject.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/kexec.h>
+#include <linux/profile.h>
+#include <linux/stat.h>
+#include <linux/sched.h>
+#include <linux/capability.h>
+#include <linux/compiler.h>
+
+#include <linux/rcupdate.h>	/* rcu_expedited and rcu_normal */
+
+#define KERNEL_ATTR_RO(_name) \
+static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
+
+#define KERNEL_ATTR_RW(_name) \
+static struct kobj_attribute _name##_attr = __ATTR_RW(_name)
+
+/* current uevent sequence number */
+static ssize_t uevent_seqnum_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
+}
+KERNEL_ATTR_RO(uevent_seqnum);
+
+#ifdef CONFIG_UEVENT_HELPER
+/* uevent helper program, used during early boot */
+static ssize_t uevent_helper_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%s\n", uevent_helper);
+}
+static ssize_t uevent_helper_store(struct kobject *kobj,
+				   struct kobj_attribute *attr,
+				   const char *buf, size_t count)
+{
+	if (count+1 > UEVENT_HELPER_PATH_LEN)
+		return -ENOENT;
+	memcpy(uevent_helper, buf, count);
+	uevent_helper[count] = '\0';
+	if (count && uevent_helper[count-1] == '\n')
+		uevent_helper[count-1] = '\0';
+	return count;
+}
+KERNEL_ATTR_RW(uevent_helper);
+#endif
+
+#ifdef CONFIG_PROFILING
+static ssize_t profiling_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", prof_on);
+}
+static ssize_t profiling_store(struct kobject *kobj,
+				   struct kobj_attribute *attr,
+				   const char *buf, size_t count)
+{
+	int ret;
+
+	if (prof_on)
+		return -EEXIST;
+	/*
+	 * This eventually calls into get_option() which
+	 * has a ton of callers and is not const.  It is
+	 * easiest to cast it away here.
+	 */
+	profile_setup((char *)buf);
+	ret = profile_init();
+	if (ret)
+		return ret;
+	ret = create_proc_profile();
+	if (ret)
+		return ret;
+	return count;
+}
+KERNEL_ATTR_RW(profiling);
+#endif
+
+#ifdef CONFIG_KEXEC_CORE
+static ssize_t kexec_loaded_show(struct kobject *kobj,
+				 struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", !!kexec_image);
+}
+KERNEL_ATTR_RO(kexec_loaded);
+
+static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
+				       struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", kexec_crash_loaded());
+}
+KERNEL_ATTR_RO(kexec_crash_loaded);
+
+static ssize_t kexec_crash_size_show(struct kobject *kobj,
+				       struct kobj_attribute *attr, char *buf)
+{
+	ssize_t size = crash_get_memory_size();
+
+	if (size < 0)
+		return size;
+
+	return sprintf(buf, "%zd\n", size);
+}
+static ssize_t kexec_crash_size_store(struct kobject *kobj,
+				   struct kobj_attribute *attr,
+				   const char *buf, size_t count)
+{
+	unsigned long cnt;
+	int ret;
+
+	if (kstrtoul(buf, 0, &cnt))
+		return -EINVAL;
+
+	ret = crash_shrink_memory(cnt);
+	return ret < 0 ? ret : count;
+}
+KERNEL_ATTR_RW(kexec_crash_size);
+
+#endif /* CONFIG_KEXEC_CORE */
+
+#ifdef CONFIG_CRASH_CORE
+
+static ssize_t vmcoreinfo_show(struct kobject *kobj,
+			       struct kobj_attribute *attr, char *buf)
+{
+	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
+	return sprintf(buf, "%pa %x\n", &vmcore_base,
+			(unsigned int)VMCOREINFO_NOTE_SIZE);
+}
+KERNEL_ATTR_RO(vmcoreinfo);
+
+#endif /* CONFIG_CRASH_CORE */
+
+/* whether file capabilities are enabled */
+static ssize_t fscaps_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", file_caps_enabled);
+}
+KERNEL_ATTR_RO(fscaps);
+
+#ifndef CONFIG_TINY_RCU
+int rcu_expedited;
+static ssize_t rcu_expedited_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited));
+}
+static ssize_t rcu_expedited_store(struct kobject *kobj,
+				   struct kobj_attribute *attr,
+				   const char *buf, size_t count)
+{
+	if (kstrtoint(buf, 0, &rcu_expedited))
+		return -EINVAL;
+
+	return count;
+}
+KERNEL_ATTR_RW(rcu_expedited);
+
+int rcu_normal;
+static ssize_t rcu_normal_show(struct kobject *kobj,
+			       struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", READ_ONCE(rcu_normal));
+}
+static ssize_t rcu_normal_store(struct kobject *kobj,
+				struct kobj_attribute *attr,
+				const char *buf, size_t count)
+{
+	if (kstrtoint(buf, 0, &rcu_normal))
+		return -EINVAL;
+
+	return count;
+}
+KERNEL_ATTR_RW(rcu_normal);
+#endif /* #ifndef CONFIG_TINY_RCU */
+
+/*
+ * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
+ */
+extern const void __start_notes __weak;
+extern const void __stop_notes __weak;
+#define	notes_size (&__stop_notes - &__start_notes)
+
+static ssize_t notes_read(struct file *filp, struct kobject *kobj,
+			  struct bin_attribute *bin_attr,
+			  char *buf, loff_t off, size_t count)
+{
+	memcpy(buf, &__start_notes + off, count);
+	return count;
+}
+
+static struct bin_attribute notes_attr __ro_after_init  = {
+	.attr = {
+		.name = "notes",
+		.mode = S_IRUGO,
+	},
+	.read = &notes_read,
+};
+
+struct kobject *kernel_kobj;
+EXPORT_SYMBOL_GPL(kernel_kobj);
+
+static struct attribute * kernel_attrs[] = {
+	&fscaps_attr.attr,
+	&uevent_seqnum_attr.attr,
+#ifdef CONFIG_UEVENT_HELPER
+	&uevent_helper_attr.attr,
+#endif
+#ifdef CONFIG_PROFILING
+	&profiling_attr.attr,
+#endif
+#ifdef CONFIG_KEXEC_CORE
+	&kexec_loaded_attr.attr,
+	&kexec_crash_loaded_attr.attr,
+	&kexec_crash_size_attr.attr,
+#endif
+#ifdef CONFIG_CRASH_CORE
+	&vmcoreinfo_attr.attr,
+#endif
+#ifndef CONFIG_TINY_RCU
+	&rcu_expedited_attr.attr,
+	&rcu_normal_attr.attr,
+#endif
+	NULL
+};
+
+static const struct attribute_group kernel_attr_group = {
+	.attrs = kernel_attrs,
+};
+
+static int __init ksysfs_init(void)
+{
+	int error;
+
+	kernel_kobj = kobject_create_and_add("kernel", NULL);
+	if (!kernel_kobj) {
+		error = -ENOMEM;
+		goto exit;
+	}
+	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
+	if (error)
+		goto kset_exit;
+
+	if (notes_size > 0) {
+		notes_attr.size = notes_size;
+		error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
+		if (error)
+			goto group_exit;
+	}
+
+	return 0;
+
+group_exit:
+	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
+kset_exit:
+	kobject_put(kernel_kobj);
+exit:
+	return error;
+}
+
+core_initcall(ksysfs_init);
diff --git a/kernel/kthread.c b/kernel/kthread.c
new file mode 100644
index 000000000..f97fd01a2
--- /dev/null
+++ b/kernel/kthread.c
@@ -0,0 +1,1525 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Kernel thread helper functions.
+ *   Copyright (C) 2004 IBM Corporation, Rusty Russell.
+ *   Copyright (C) 2009 Red Hat, Inc.
+ *
+ * Creation is done via kthreadd, so that we get a clean environment
+ * even if we're invoked from userspace (think modprobe, hotplug cpu,
+ * etc.).
+ */
+#include <uapi/linux/sched/types.h>
+#include <linux/mm.h>
+#include <linux/mmu_context.h>
+#include <linux/sched.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/task.h>
+#include <linux/kthread.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/cgroup.h>
+#include <linux/cpuset.h>
+#include <linux/unistd.h>
+#include <linux/file.h>
+#include <linux/export.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/freezer.h>
+#include <linux/ptrace.h>
+#include <linux/uaccess.h>
+#include <linux/numa.h>
+#include <linux/sched/isolation.h>
+#include <trace/events/sched.h>
+
+
+static DEFINE_SPINLOCK(kthread_create_lock);
+static LIST_HEAD(kthread_create_list);
+struct task_struct *kthreadd_task;
+
+struct kthread_create_info
+{
+	/* Information passed to kthread() from kthreadd. */
+	int (*threadfn)(void *data);
+	void *data;
+	int node;
+
+	/* Result passed back to kthread_create() from kthreadd. */
+	struct task_struct *result;
+	struct completion *done;
+
+	struct list_head list;
+};
+
+struct kthread {
+	unsigned long flags;
+	unsigned int cpu;
+	int result;
+	int (*threadfn)(void *);
+	void *data;
+	struct completion parked;
+	struct completion exited;
+#ifdef CONFIG_BLK_CGROUP
+	struct cgroup_subsys_state *blkcg_css;
+#endif
+	/* To store the full name if task comm is truncated. */
+	char *full_name;
+};
+
+enum KTHREAD_BITS {
+	KTHREAD_IS_PER_CPU = 0,
+	KTHREAD_SHOULD_STOP,
+	KTHREAD_SHOULD_PARK,
+};
+
+static inline struct kthread *to_kthread(struct task_struct *k)
+{
+	WARN_ON(!(k->flags & PF_KTHREAD));
+	return k->worker_private;
+}
+
+/*
+ * Variant of to_kthread() that doesn't assume @p is a kthread.
+ *
+ * Per construction; when:
+ *
+ *   (p->flags & PF_KTHREAD) && p->worker_private
+ *
+ * the task is both a kthread and struct kthread is persistent. However
+ * PF_KTHREAD on it's own is not, kernel_thread() can exec() (See umh.c and
+ * begin_new_exec()).
+ */
+static inline struct kthread *__to_kthread(struct task_struct *p)
+{
+	void *kthread = p->worker_private;
+	if (kthread && !(p->flags & PF_KTHREAD))
+		kthread = NULL;
+	return kthread;
+}
+
+void get_kthread_comm(char *buf, size_t buf_size, struct task_struct *tsk)
+{
+	struct kthread *kthread = to_kthread(tsk);
+
+	if (!kthread || !kthread->full_name) {
+		__get_task_comm(buf, buf_size, tsk);
+		return;
+	}
+
+	strscpy_pad(buf, kthread->full_name, buf_size);
+}
+
+bool set_kthread_struct(struct task_struct *p)
+{
+	struct kthread *kthread;
+
+	if (WARN_ON_ONCE(to_kthread(p)))
+		return false;
+
+	kthread = kzalloc(sizeof(*kthread), GFP_KERNEL);
+	if (!kthread)
+		return false;
+
+	init_completion(&kthread->exited);
+	init_completion(&kthread->parked);
+	p->vfork_done = &kthread->exited;
+
+	p->worker_private = kthread;
+	return true;
+}
+
+void free_kthread_struct(struct task_struct *k)
+{
+	struct kthread *kthread;
+
+	/*
+	 * Can be NULL if kmalloc() in set_kthread_struct() failed.
+	 */
+	kthread = to_kthread(k);
+	if (!kthread)
+		return;
+
+#ifdef CONFIG_BLK_CGROUP
+	WARN_ON_ONCE(kthread->blkcg_css);
+#endif
+	k->worker_private = NULL;
+	kfree(kthread->full_name);
+	kfree(kthread);
+}
+
+/**
+ * kthread_should_stop - should this kthread return now?
+ *
+ * When someone calls kthread_stop() on your kthread, it will be woken
+ * and this will return true.  You should then return, and your return
+ * value will be passed through to kthread_stop().
+ */
+bool kthread_should_stop(void)
+{
+	return test_bit(KTHREAD_SHOULD_STOP, &to_kthread(current)->flags);
+}
+EXPORT_SYMBOL(kthread_should_stop);
+
+bool __kthread_should_park(struct task_struct *k)
+{
+	return test_bit(KTHREAD_SHOULD_PARK, &to_kthread(k)->flags);
+}
+EXPORT_SYMBOL_GPL(__kthread_should_park);
+
+/**
+ * kthread_should_park - should this kthread park now?
+ *
+ * When someone calls kthread_park() on your kthread, it will be woken
+ * and this will return true.  You should then do the necessary
+ * cleanup and call kthread_parkme()
+ *
+ * Similar to kthread_should_stop(), but this keeps the thread alive
+ * and in a park position. kthread_unpark() "restarts" the thread and
+ * calls the thread function again.
+ */
+bool kthread_should_park(void)
+{
+	return __kthread_should_park(current);
+}
+EXPORT_SYMBOL_GPL(kthread_should_park);
+
+/**
+ * kthread_freezable_should_stop - should this freezable kthread return now?
+ * @was_frozen: optional out parameter, indicates whether %current was frozen
+ *
+ * kthread_should_stop() for freezable kthreads, which will enter
+ * refrigerator if necessary.  This function is safe from kthread_stop() /
+ * freezer deadlock and freezable kthreads should use this function instead
+ * of calling try_to_freeze() directly.
+ */
+bool kthread_freezable_should_stop(bool *was_frozen)
+{
+	bool frozen = false;
+
+	might_sleep();
+
+	if (unlikely(freezing(current)))
+		frozen = __refrigerator(true);
+
+	if (was_frozen)
+		*was_frozen = frozen;
+
+	return kthread_should_stop();
+}
+EXPORT_SYMBOL_GPL(kthread_freezable_should_stop);
+
+/**
+ * kthread_func - return the function specified on kthread creation
+ * @task: kthread task in question
+ *
+ * Returns NULL if the task is not a kthread.
+ */
+void *kthread_func(struct task_struct *task)
+{
+	struct kthread *kthread = __to_kthread(task);
+	if (kthread)
+		return kthread->threadfn;
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(kthread_func);
+
+/**
+ * kthread_data - return data value specified on kthread creation
+ * @task: kthread task in question
+ *
+ * Return the data value specified when kthread @task was created.
+ * The caller is responsible for ensuring the validity of @task when
+ * calling this function.
+ */
+void *kthread_data(struct task_struct *task)
+{
+	return to_kthread(task)->data;
+}
+EXPORT_SYMBOL_GPL(kthread_data);
+
+/**
+ * kthread_probe_data - speculative version of kthread_data()
+ * @task: possible kthread task in question
+ *
+ * @task could be a kthread task.  Return the data value specified when it
+ * was created if accessible.  If @task isn't a kthread task or its data is
+ * inaccessible for any reason, %NULL is returned.  This function requires
+ * that @task itself is safe to dereference.
+ */
+void *kthread_probe_data(struct task_struct *task)
+{
+	struct kthread *kthread = __to_kthread(task);
+	void *data = NULL;
+
+	if (kthread)
+		copy_from_kernel_nofault(&data, &kthread->data, sizeof(data));
+	return data;
+}
+
+static void __kthread_parkme(struct kthread *self)
+{
+	for (;;) {
+		/*
+		 * TASK_PARKED is a special state; we must serialize against
+		 * possible pending wakeups to avoid store-store collisions on
+		 * task->state.
+		 *
+		 * Such a collision might possibly result in the task state
+		 * changin from TASK_PARKED and us failing the
+		 * wait_task_inactive() in kthread_park().
+		 */
+		set_special_state(TASK_PARKED);
+		if (!test_bit(KTHREAD_SHOULD_PARK, &self->flags))
+			break;
+
+		/*
+		 * Thread is going to call schedule(), do not preempt it,
+		 * or the caller of kthread_park() may spend more time in
+		 * wait_task_inactive().
+		 */
+		preempt_disable();
+		complete(&self->parked);
+		schedule_preempt_disabled();
+		preempt_enable();
+	}
+	__set_current_state(TASK_RUNNING);
+}
+
+void kthread_parkme(void)
+{
+	__kthread_parkme(to_kthread(current));
+}
+EXPORT_SYMBOL_GPL(kthread_parkme);
+
+/**
+ * kthread_exit - Cause the current kthread return @result to kthread_stop().
+ * @result: The integer value to return to kthread_stop().
+ *
+ * While kthread_exit can be called directly, it exists so that
+ * functions which do some additional work in non-modular code such as
+ * module_put_and_kthread_exit can be implemented.
+ *
+ * Does not return.
+ */
+void __noreturn kthread_exit(long result)
+{
+	struct kthread *kthread = to_kthread(current);
+	kthread->result = result;
+	do_exit(0);
+}
+
+/**
+ * kthread_complete_and_exit - Exit the current kthread.
+ * @comp: Completion to complete
+ * @code: The integer value to return to kthread_stop().
+ *
+ * If present complete @comp and the reuturn code to kthread_stop().
+ *
+ * A kernel thread whose module may be removed after the completion of
+ * @comp can use this function exit safely.
+ *
+ * Does not return.
+ */
+void __noreturn kthread_complete_and_exit(struct completion *comp, long code)
+{
+	if (comp)
+		complete(comp);
+
+	kthread_exit(code);
+}
+EXPORT_SYMBOL(kthread_complete_and_exit);
+
+static int kthread(void *_create)
+{
+	static const struct sched_param param = { .sched_priority = 0 };
+	/* Copy data: it's on kthread's stack */
+	struct kthread_create_info *create = _create;
+	int (*threadfn)(void *data) = create->threadfn;
+	void *data = create->data;
+	struct completion *done;
+	struct kthread *self;
+	int ret;
+
+	self = to_kthread(current);
+
+	/* Release the structure when caller killed by a fatal signal. */
+	done = xchg(&create->done, NULL);
+	if (!done) {
+		kfree(create);
+		kthread_exit(-EINTR);
+	}
+
+	self->threadfn = threadfn;
+	self->data = data;
+
+	/*
+	 * The new thread inherited kthreadd's priority and CPU mask. Reset
+	 * back to default in case they have been changed.
+	 */
+	sched_setscheduler_nocheck(current, SCHED_NORMAL, &param);
+	set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_TYPE_KTHREAD));
+
+	/* OK, tell user we're spawned, wait for stop or wakeup */
+	__set_current_state(TASK_UNINTERRUPTIBLE);
+	create->result = current;
+	/*
+	 * Thread is going to call schedule(), do not preempt it,
+	 * or the creator may spend more time in wait_task_inactive().
+	 */
+	preempt_disable();
+	complete(done);
+	schedule_preempt_disabled();
+	preempt_enable();
+
+	ret = -EINTR;
+	if (!test_bit(KTHREAD_SHOULD_STOP, &self->flags)) {
+		cgroup_kthread_ready();
+		__kthread_parkme(self);
+		ret = threadfn(data);
+	}
+	kthread_exit(ret);
+}
+
+/* called from kernel_clone() to get node information for about to be created task */
+int tsk_fork_get_node(struct task_struct *tsk)
+{
+#ifdef CONFIG_NUMA
+	if (tsk == kthreadd_task)
+		return tsk->pref_node_fork;
+#endif
+	return NUMA_NO_NODE;
+}
+
+static void create_kthread(struct kthread_create_info *create)
+{
+	int pid;
+
+#ifdef CONFIG_NUMA
+	current->pref_node_fork = create->node;
+#endif
+	/* We want our own signal handler (we take no signals by default). */
+	pid = kernel_thread(kthread, create, CLONE_FS | CLONE_FILES | SIGCHLD);
+	if (pid < 0) {
+		/* Release the structure when caller killed by a fatal signal. */
+		struct completion *done = xchg(&create->done, NULL);
+
+		if (!done) {
+			kfree(create);
+			return;
+		}
+		create->result = ERR_PTR(pid);
+		complete(done);
+	}
+}
+
+static __printf(4, 0)
+struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data),
+						    void *data, int node,
+						    const char namefmt[],
+						    va_list args)
+{
+	DECLARE_COMPLETION_ONSTACK(done);
+	struct task_struct *task;
+	struct kthread_create_info *create = kmalloc(sizeof(*create),
+						     GFP_KERNEL);
+
+	if (!create)
+		return ERR_PTR(-ENOMEM);
+	create->threadfn = threadfn;
+	create->data = data;
+	create->node = node;
+	create->done = &done;
+
+	spin_lock(&kthread_create_lock);
+	list_add_tail(&create->list, &kthread_create_list);
+	spin_unlock(&kthread_create_lock);
+
+	wake_up_process(kthreadd_task);
+	/*
+	 * Wait for completion in killable state, for I might be chosen by
+	 * the OOM killer while kthreadd is trying to allocate memory for
+	 * new kernel thread.
+	 */
+	if (unlikely(wait_for_completion_killable(&done))) {
+		/*
+		 * If I was killed by a fatal signal before kthreadd (or new
+		 * kernel thread) calls complete(), leave the cleanup of this
+		 * structure to that thread.
+		 */
+		if (xchg(&create->done, NULL))
+			return ERR_PTR(-EINTR);
+		/*
+		 * kthreadd (or new kernel thread) will call complete()
+		 * shortly.
+		 */
+		wait_for_completion(&done);
+	}
+	task = create->result;
+	if (!IS_ERR(task)) {
+		char name[TASK_COMM_LEN];
+		va_list aq;
+		int len;
+
+		/*
+		 * task is already visible to other tasks, so updating
+		 * COMM must be protected.
+		 */
+		va_copy(aq, args);
+		len = vsnprintf(name, sizeof(name), namefmt, aq);
+		va_end(aq);
+		if (len >= TASK_COMM_LEN) {
+			struct kthread *kthread = to_kthread(task);
+
+			/* leave it truncated when out of memory. */
+			kthread->full_name = kvasprintf(GFP_KERNEL, namefmt, args);
+		}
+		set_task_comm(task, name);
+	}
+	kfree(create);
+	return task;
+}
+
+/**
+ * kthread_create_on_node - create a kthread.
+ * @threadfn: the function to run until signal_pending(current).
+ * @data: data ptr for @threadfn.
+ * @node: task and thread structures for the thread are allocated on this node
+ * @namefmt: printf-style name for the thread.
+ *
+ * Description: This helper function creates and names a kernel
+ * thread.  The thread will be stopped: use wake_up_process() to start
+ * it.  See also kthread_run().  The new thread has SCHED_NORMAL policy and
+ * is affine to all CPUs.
+ *
+ * If thread is going to be bound on a particular cpu, give its node
+ * in @node, to get NUMA affinity for kthread stack, or else give NUMA_NO_NODE.
+ * When woken, the thread will run @threadfn() with @data as its
+ * argument. @threadfn() can either return directly if it is a
+ * standalone thread for which no one will call kthread_stop(), or
+ * return when 'kthread_should_stop()' is true (which means
+ * kthread_stop() has been called).  The return value should be zero
+ * or a negative error number; it will be passed to kthread_stop().
+ *
+ * Returns a task_struct or ERR_PTR(-ENOMEM) or ERR_PTR(-EINTR).
+ */
+struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
+					   void *data, int node,
+					   const char namefmt[],
+					   ...)
+{
+	struct task_struct *task;
+	va_list args;
+
+	va_start(args, namefmt);
+	task = __kthread_create_on_node(threadfn, data, node, namefmt, args);
+	va_end(args);
+
+	return task;
+}
+EXPORT_SYMBOL(kthread_create_on_node);
+
+static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, unsigned int state)
+{
+	unsigned long flags;
+
+	if (!wait_task_inactive(p, state)) {
+		WARN_ON(1);
+		return;
+	}
+
+	/* It's safe because the task is inactive. */
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	do_set_cpus_allowed(p, mask);
+	p->flags |= PF_NO_SETAFFINITY;
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+}
+
+static void __kthread_bind(struct task_struct *p, unsigned int cpu, unsigned int state)
+{
+	__kthread_bind_mask(p, cpumask_of(cpu), state);
+}
+
+void kthread_bind_mask(struct task_struct *p, const struct cpumask *mask)
+{
+	__kthread_bind_mask(p, mask, TASK_UNINTERRUPTIBLE);
+}
+
+/**
+ * kthread_bind - bind a just-created kthread to a cpu.
+ * @p: thread created by kthread_create().
+ * @cpu: cpu (might not be online, must be possible) for @k to run on.
+ *
+ * Description: This function is equivalent to set_cpus_allowed(),
+ * except that @cpu doesn't need to be online, and the thread must be
+ * stopped (i.e., just returned from kthread_create()).
+ */
+void kthread_bind(struct task_struct *p, unsigned int cpu)
+{
+	__kthread_bind(p, cpu, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(kthread_bind);
+
+/**
+ * kthread_create_on_cpu - Create a cpu bound kthread
+ * @threadfn: the function to run until signal_pending(current).
+ * @data: data ptr for @threadfn.
+ * @cpu: The cpu on which the thread should be bound,
+ * @namefmt: printf-style name for the thread. Format is restricted
+ *	     to "name.*%u". Code fills in cpu number.
+ *
+ * Description: This helper function creates and names a kernel thread
+ */
+struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
+					  void *data, unsigned int cpu,
+					  const char *namefmt)
+{
+	struct task_struct *p;
+
+	p = kthread_create_on_node(threadfn, data, cpu_to_node(cpu), namefmt,
+				   cpu);
+	if (IS_ERR(p))
+		return p;
+	kthread_bind(p, cpu);
+	/* CPU hotplug need to bind once again when unparking the thread. */
+	to_kthread(p)->cpu = cpu;
+	return p;
+}
+EXPORT_SYMBOL(kthread_create_on_cpu);
+
+void kthread_set_per_cpu(struct task_struct *k, int cpu)
+{
+	struct kthread *kthread = to_kthread(k);
+	if (!kthread)
+		return;
+
+	WARN_ON_ONCE(!(k->flags & PF_NO_SETAFFINITY));
+
+	if (cpu < 0) {
+		clear_bit(KTHREAD_IS_PER_CPU, &kthread->flags);
+		return;
+	}
+
+	kthread->cpu = cpu;
+	set_bit(KTHREAD_IS_PER_CPU, &kthread->flags);
+}
+
+bool kthread_is_per_cpu(struct task_struct *p)
+{
+	struct kthread *kthread = __to_kthread(p);
+	if (!kthread)
+		return false;
+
+	return test_bit(KTHREAD_IS_PER_CPU, &kthread->flags);
+}
+
+/**
+ * kthread_unpark - unpark a thread created by kthread_create().
+ * @k:		thread created by kthread_create().
+ *
+ * Sets kthread_should_park() for @k to return false, wakes it, and
+ * waits for it to return. If the thread is marked percpu then its
+ * bound to the cpu again.
+ */
+void kthread_unpark(struct task_struct *k)
+{
+	struct kthread *kthread = to_kthread(k);
+
+	/*
+	 * Newly created kthread was parked when the CPU was offline.
+	 * The binding was lost and we need to set it again.
+	 */
+	if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags))
+		__kthread_bind(k, kthread->cpu, TASK_PARKED);
+
+	clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
+	/*
+	 * __kthread_parkme() will either see !SHOULD_PARK or get the wakeup.
+	 */
+	wake_up_state(k, TASK_PARKED);
+}
+EXPORT_SYMBOL_GPL(kthread_unpark);
+
+/**
+ * kthread_park - park a thread created by kthread_create().
+ * @k: thread created by kthread_create().
+ *
+ * Sets kthread_should_park() for @k to return true, wakes it, and
+ * waits for it to return. This can also be called after kthread_create()
+ * instead of calling wake_up_process(): the thread will park without
+ * calling threadfn().
+ *
+ * Returns 0 if the thread is parked, -ENOSYS if the thread exited.
+ * If called by the kthread itself just the park bit is set.
+ */
+int kthread_park(struct task_struct *k)
+{
+	struct kthread *kthread = to_kthread(k);
+
+	if (WARN_ON(k->flags & PF_EXITING))
+		return -ENOSYS;
+
+	if (WARN_ON_ONCE(test_bit(KTHREAD_SHOULD_PARK, &kthread->flags)))
+		return -EBUSY;
+
+	set_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
+	if (k != current) {
+		wake_up_process(k);
+		/*
+		 * Wait for __kthread_parkme() to complete(), this means we
+		 * _will_ have TASK_PARKED and are about to call schedule().
+		 */
+		wait_for_completion(&kthread->parked);
+		/*
+		 * Now wait for that schedule() to complete and the task to
+		 * get scheduled out.
+		 */
+		WARN_ON_ONCE(!wait_task_inactive(k, TASK_PARKED));
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kthread_park);
+
+/**
+ * kthread_stop - stop a thread created by kthread_create().
+ * @k: thread created by kthread_create().
+ *
+ * Sets kthread_should_stop() for @k to return true, wakes it, and
+ * waits for it to exit. This can also be called after kthread_create()
+ * instead of calling wake_up_process(): the thread will exit without
+ * calling threadfn().
+ *
+ * If threadfn() may call kthread_exit() itself, the caller must ensure
+ * task_struct can't go away.
+ *
+ * Returns the result of threadfn(), or %-EINTR if wake_up_process()
+ * was never called.
+ */
+int kthread_stop(struct task_struct *k)
+{
+	struct kthread *kthread;
+	int ret;
+
+	trace_sched_kthread_stop(k);
+
+	get_task_struct(k);
+	kthread = to_kthread(k);
+	set_bit(KTHREAD_SHOULD_STOP, &kthread->flags);
+	kthread_unpark(k);
+	set_tsk_thread_flag(k, TIF_NOTIFY_SIGNAL);
+	wake_up_process(k);
+	wait_for_completion(&kthread->exited);
+	ret = kthread->result;
+	put_task_struct(k);
+
+	trace_sched_kthread_stop_ret(ret);
+	return ret;
+}
+EXPORT_SYMBOL(kthread_stop);
+
+int kthreadd(void *unused)
+{
+	struct task_struct *tsk = current;
+
+	/* Setup a clean context for our children to inherit. */
+	set_task_comm(tsk, "kthreadd");
+	ignore_signals(tsk);
+	set_cpus_allowed_ptr(tsk, housekeeping_cpumask(HK_TYPE_KTHREAD));
+	set_mems_allowed(node_states[N_MEMORY]);
+
+	current->flags |= PF_NOFREEZE;
+	cgroup_init_kthreadd();
+
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (list_empty(&kthread_create_list))
+			schedule();
+		__set_current_state(TASK_RUNNING);
+
+		spin_lock(&kthread_create_lock);
+		while (!list_empty(&kthread_create_list)) {
+			struct kthread_create_info *create;
+
+			create = list_entry(kthread_create_list.next,
+					    struct kthread_create_info, list);
+			list_del_init(&create->list);
+			spin_unlock(&kthread_create_lock);
+
+			create_kthread(create);
+
+			spin_lock(&kthread_create_lock);
+		}
+		spin_unlock(&kthread_create_lock);
+	}
+
+	return 0;
+}
+
+void __kthread_init_worker(struct kthread_worker *worker,
+				const char *name,
+				struct lock_class_key *key)
+{
+	memset(worker, 0, sizeof(struct kthread_worker));
+	raw_spin_lock_init(&worker->lock);
+	lockdep_set_class_and_name(&worker->lock, key, name);
+	INIT_LIST_HEAD(&worker->work_list);
+	INIT_LIST_HEAD(&worker->delayed_work_list);
+}
+EXPORT_SYMBOL_GPL(__kthread_init_worker);
+
+/**
+ * kthread_worker_fn - kthread function to process kthread_worker
+ * @worker_ptr: pointer to initialized kthread_worker
+ *
+ * This function implements the main cycle of kthread worker. It processes
+ * work_list until it is stopped with kthread_stop(). It sleeps when the queue
+ * is empty.
+ *
+ * The works are not allowed to keep any locks, disable preemption or interrupts
+ * when they finish. There is defined a safe point for freezing when one work
+ * finishes and before a new one is started.
+ *
+ * Also the works must not be handled by more than one worker at the same time,
+ * see also kthread_queue_work().
+ */
+int kthread_worker_fn(void *worker_ptr)
+{
+	struct kthread_worker *worker = worker_ptr;
+	struct kthread_work *work;
+
+	/*
+	 * FIXME: Update the check and remove the assignment when all kthread
+	 * worker users are created using kthread_create_worker*() functions.
+	 */
+	WARN_ON(worker->task && worker->task != current);
+	worker->task = current;
+
+	if (worker->flags & KTW_FREEZABLE)
+		set_freezable();
+
+repeat:
+	set_current_state(TASK_INTERRUPTIBLE);	/* mb paired w/ kthread_stop */
+
+	if (kthread_should_stop()) {
+		__set_current_state(TASK_RUNNING);
+		raw_spin_lock_irq(&worker->lock);
+		worker->task = NULL;
+		raw_spin_unlock_irq(&worker->lock);
+		return 0;
+	}
+
+	work = NULL;
+	raw_spin_lock_irq(&worker->lock);
+	if (!list_empty(&worker->work_list)) {
+		work = list_first_entry(&worker->work_list,
+					struct kthread_work, node);
+		list_del_init(&work->node);
+	}
+	worker->current_work = work;
+	raw_spin_unlock_irq(&worker->lock);
+
+	if (work) {
+		kthread_work_func_t func = work->func;
+		__set_current_state(TASK_RUNNING);
+		trace_sched_kthread_work_execute_start(work);
+		work->func(work);
+		/*
+		 * Avoid dereferencing work after this point.  The trace
+		 * event only cares about the address.
+		 */
+		trace_sched_kthread_work_execute_end(work, func);
+	} else if (!freezing(current))
+		schedule();
+
+	try_to_freeze();
+	cond_resched();
+	goto repeat;
+}
+EXPORT_SYMBOL_GPL(kthread_worker_fn);
+
+static __printf(3, 0) struct kthread_worker *
+__kthread_create_worker(int cpu, unsigned int flags,
+			const char namefmt[], va_list args)
+{
+	struct kthread_worker *worker;
+	struct task_struct *task;
+	int node = NUMA_NO_NODE;
+
+	worker = kzalloc(sizeof(*worker), GFP_KERNEL);
+	if (!worker)
+		return ERR_PTR(-ENOMEM);
+
+	kthread_init_worker(worker);
+
+	if (cpu >= 0)
+		node = cpu_to_node(cpu);
+
+	task = __kthread_create_on_node(kthread_worker_fn, worker,
+						node, namefmt, args);
+	if (IS_ERR(task))
+		goto fail_task;
+
+	if (cpu >= 0)
+		kthread_bind(task, cpu);
+
+	worker->flags = flags;
+	worker->task = task;
+	wake_up_process(task);
+	return worker;
+
+fail_task:
+	kfree(worker);
+	return ERR_CAST(task);
+}
+
+/**
+ * kthread_create_worker - create a kthread worker
+ * @flags: flags modifying the default behavior of the worker
+ * @namefmt: printf-style name for the kthread worker (task).
+ *
+ * Returns a pointer to the allocated worker on success, ERR_PTR(-ENOMEM)
+ * when the needed structures could not get allocated, and ERR_PTR(-EINTR)
+ * when the caller was killed by a fatal signal.
+ */
+struct kthread_worker *
+kthread_create_worker(unsigned int flags, const char namefmt[], ...)
+{
+	struct kthread_worker *worker;
+	va_list args;
+
+	va_start(args, namefmt);
+	worker = __kthread_create_worker(-1, flags, namefmt, args);
+	va_end(args);
+
+	return worker;
+}
+EXPORT_SYMBOL(kthread_create_worker);
+
+/**
+ * kthread_create_worker_on_cpu - create a kthread worker and bind it
+ *	to a given CPU and the associated NUMA node.
+ * @cpu: CPU number
+ * @flags: flags modifying the default behavior of the worker
+ * @namefmt: printf-style name for the kthread worker (task).
+ *
+ * Use a valid CPU number if you want to bind the kthread worker
+ * to the given CPU and the associated NUMA node.
+ *
+ * A good practice is to add the cpu number also into the worker name.
+ * For example, use kthread_create_worker_on_cpu(cpu, "helper/%d", cpu).
+ *
+ * CPU hotplug:
+ * The kthread worker API is simple and generic. It just provides a way
+ * to create, use, and destroy workers.
+ *
+ * It is up to the API user how to handle CPU hotplug. They have to decide
+ * how to handle pending work items, prevent queuing new ones, and
+ * restore the functionality when the CPU goes off and on. There are a
+ * few catches:
+ *
+ *    - CPU affinity gets lost when it is scheduled on an offline CPU.
+ *
+ *    - The worker might not exist when the CPU was off when the user
+ *      created the workers.
+ *
+ * Good practice is to implement two CPU hotplug callbacks and to
+ * destroy/create the worker when the CPU goes down/up.
+ *
+ * Return:
+ * The pointer to the allocated worker on success, ERR_PTR(-ENOMEM)
+ * when the needed structures could not get allocated, and ERR_PTR(-EINTR)
+ * when the caller was killed by a fatal signal.
+ */
+struct kthread_worker *
+kthread_create_worker_on_cpu(int cpu, unsigned int flags,
+			     const char namefmt[], ...)
+{
+	struct kthread_worker *worker;
+	va_list args;
+
+	va_start(args, namefmt);
+	worker = __kthread_create_worker(cpu, flags, namefmt, args);
+	va_end(args);
+
+	return worker;
+}
+EXPORT_SYMBOL(kthread_create_worker_on_cpu);
+
+/*
+ * Returns true when the work could not be queued at the moment.
+ * It happens when it is already pending in a worker list
+ * or when it is being cancelled.
+ */
+static inline bool queuing_blocked(struct kthread_worker *worker,
+				   struct kthread_work *work)
+{
+	lockdep_assert_held(&worker->lock);
+
+	return !list_empty(&work->node) || work->canceling;
+}
+
+static void kthread_insert_work_sanity_check(struct kthread_worker *worker,
+					     struct kthread_work *work)
+{
+	lockdep_assert_held(&worker->lock);
+	WARN_ON_ONCE(!list_empty(&work->node));
+	/* Do not use a work with >1 worker, see kthread_queue_work() */
+	WARN_ON_ONCE(work->worker && work->worker != worker);
+}
+
+/* insert @work before @pos in @worker */
+static void kthread_insert_work(struct kthread_worker *worker,
+				struct kthread_work *work,
+				struct list_head *pos)
+{
+	kthread_insert_work_sanity_check(worker, work);
+
+	trace_sched_kthread_work_queue_work(worker, work);
+
+	list_add_tail(&work->node, pos);
+	work->worker = worker;
+	if (!worker->current_work && likely(worker->task))
+		wake_up_process(worker->task);
+}
+
+/**
+ * kthread_queue_work - queue a kthread_work
+ * @worker: target kthread_worker
+ * @work: kthread_work to queue
+ *
+ * Queue @work to work processor @task for async execution.  @task
+ * must have been created with kthread_worker_create().  Returns %true
+ * if @work was successfully queued, %false if it was already pending.
+ *
+ * Reinitialize the work if it needs to be used by another worker.
+ * For example, when the worker was stopped and started again.
+ */
+bool kthread_queue_work(struct kthread_worker *worker,
+			struct kthread_work *work)
+{
+	bool ret = false;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&worker->lock, flags);
+	if (!queuing_blocked(worker, work)) {
+		kthread_insert_work(worker, work, &worker->work_list);
+		ret = true;
+	}
+	raw_spin_unlock_irqrestore(&worker->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kthread_queue_work);
+
+/**
+ * kthread_delayed_work_timer_fn - callback that queues the associated kthread
+ *	delayed work when the timer expires.
+ * @t: pointer to the expired timer
+ *
+ * The format of the function is defined by struct timer_list.
+ * It should have been called from irqsafe timer with irq already off.
+ */
+void kthread_delayed_work_timer_fn(struct timer_list *t)
+{
+	struct kthread_delayed_work *dwork = from_timer(dwork, t, timer);
+	struct kthread_work *work = &dwork->work;
+	struct kthread_worker *worker = work->worker;
+	unsigned long flags;
+
+	/*
+	 * This might happen when a pending work is reinitialized.
+	 * It means that it is used a wrong way.
+	 */
+	if (WARN_ON_ONCE(!worker))
+		return;
+
+	raw_spin_lock_irqsave(&worker->lock, flags);
+	/* Work must not be used with >1 worker, see kthread_queue_work(). */
+	WARN_ON_ONCE(work->worker != worker);
+
+	/* Move the work from worker->delayed_work_list. */
+	WARN_ON_ONCE(list_empty(&work->node));
+	list_del_init(&work->node);
+	if (!work->canceling)
+		kthread_insert_work(worker, work, &worker->work_list);
+
+	raw_spin_unlock_irqrestore(&worker->lock, flags);
+}
+EXPORT_SYMBOL(kthread_delayed_work_timer_fn);
+
+static void __kthread_queue_delayed_work(struct kthread_worker *worker,
+					 struct kthread_delayed_work *dwork,
+					 unsigned long delay)
+{
+	struct timer_list *timer = &dwork->timer;
+	struct kthread_work *work = &dwork->work;
+
+	WARN_ON_ONCE(timer->function != kthread_delayed_work_timer_fn);
+
+	/*
+	 * If @delay is 0, queue @dwork->work immediately.  This is for
+	 * both optimization and correctness.  The earliest @timer can
+	 * expire is on the closest next tick and delayed_work users depend
+	 * on that there's no such delay when @delay is 0.
+	 */
+	if (!delay) {
+		kthread_insert_work(worker, work, &worker->work_list);
+		return;
+	}
+
+	/* Be paranoid and try to detect possible races already now. */
+	kthread_insert_work_sanity_check(worker, work);
+
+	list_add(&work->node, &worker->delayed_work_list);
+	work->worker = worker;
+	timer->expires = jiffies + delay;
+	add_timer(timer);
+}
+
+/**
+ * kthread_queue_delayed_work - queue the associated kthread work
+ *	after a delay.
+ * @worker: target kthread_worker
+ * @dwork: kthread_delayed_work to queue
+ * @delay: number of jiffies to wait before queuing
+ *
+ * If the work has not been pending it starts a timer that will queue
+ * the work after the given @delay. If @delay is zero, it queues the
+ * work immediately.
+ *
+ * Return: %false if the @work has already been pending. It means that
+ * either the timer was running or the work was queued. It returns %true
+ * otherwise.
+ */
+bool kthread_queue_delayed_work(struct kthread_worker *worker,
+				struct kthread_delayed_work *dwork,
+				unsigned long delay)
+{
+	struct kthread_work *work = &dwork->work;
+	unsigned long flags;
+	bool ret = false;
+
+	raw_spin_lock_irqsave(&worker->lock, flags);
+
+	if (!queuing_blocked(worker, work)) {
+		__kthread_queue_delayed_work(worker, dwork, delay);
+		ret = true;
+	}
+
+	raw_spin_unlock_irqrestore(&worker->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kthread_queue_delayed_work);
+
+struct kthread_flush_work {
+	struct kthread_work	work;
+	struct completion	done;
+};
+
+static void kthread_flush_work_fn(struct kthread_work *work)
+{
+	struct kthread_flush_work *fwork =
+		container_of(work, struct kthread_flush_work, work);
+	complete(&fwork->done);
+}
+
+/**
+ * kthread_flush_work - flush a kthread_work
+ * @work: work to flush
+ *
+ * If @work is queued or executing, wait for it to finish execution.
+ */
+void kthread_flush_work(struct kthread_work *work)
+{
+	struct kthread_flush_work fwork = {
+		KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),
+		COMPLETION_INITIALIZER_ONSTACK(fwork.done),
+	};
+	struct kthread_worker *worker;
+	bool noop = false;
+
+	worker = work->worker;
+	if (!worker)
+		return;
+
+	raw_spin_lock_irq(&worker->lock);
+	/* Work must not be used with >1 worker, see kthread_queue_work(). */
+	WARN_ON_ONCE(work->worker != worker);
+
+	if (!list_empty(&work->node))
+		kthread_insert_work(worker, &fwork.work, work->node.next);
+	else if (worker->current_work == work)
+		kthread_insert_work(worker, &fwork.work,
+				    worker->work_list.next);
+	else
+		noop = true;
+
+	raw_spin_unlock_irq(&worker->lock);
+
+	if (!noop)
+		wait_for_completion(&fwork.done);
+}
+EXPORT_SYMBOL_GPL(kthread_flush_work);
+
+/*
+ * Make sure that the timer is neither set nor running and could
+ * not manipulate the work list_head any longer.
+ *
+ * The function is called under worker->lock. The lock is temporary
+ * released but the timer can't be set again in the meantime.
+ */
+static void kthread_cancel_delayed_work_timer(struct kthread_work *work,
+					      unsigned long *flags)
+{
+	struct kthread_delayed_work *dwork =
+		container_of(work, struct kthread_delayed_work, work);
+	struct kthread_worker *worker = work->worker;
+
+	/*
+	 * del_timer_sync() must be called to make sure that the timer
+	 * callback is not running. The lock must be temporary released
+	 * to avoid a deadlock with the callback. In the meantime,
+	 * any queuing is blocked by setting the canceling counter.
+	 */
+	work->canceling++;
+	raw_spin_unlock_irqrestore(&worker->lock, *flags);
+	del_timer_sync(&dwork->timer);
+	raw_spin_lock_irqsave(&worker->lock, *flags);
+	work->canceling--;
+}
+
+/*
+ * This function removes the work from the worker queue.
+ *
+ * It is called under worker->lock. The caller must make sure that
+ * the timer used by delayed work is not running, e.g. by calling
+ * kthread_cancel_delayed_work_timer().
+ *
+ * The work might still be in use when this function finishes. See the
+ * current_work proceed by the worker.
+ *
+ * Return: %true if @work was pending and successfully canceled,
+ *	%false if @work was not pending
+ */
+static bool __kthread_cancel_work(struct kthread_work *work)
+{
+	/*
+	 * Try to remove the work from a worker list. It might either
+	 * be from worker->work_list or from worker->delayed_work_list.
+	 */
+	if (!list_empty(&work->node)) {
+		list_del_init(&work->node);
+		return true;
+	}
+
+	return false;
+}
+
+/**
+ * kthread_mod_delayed_work - modify delay of or queue a kthread delayed work
+ * @worker: kthread worker to use
+ * @dwork: kthread delayed work to queue
+ * @delay: number of jiffies to wait before queuing
+ *
+ * If @dwork is idle, equivalent to kthread_queue_delayed_work(). Otherwise,
+ * modify @dwork's timer so that it expires after @delay. If @delay is zero,
+ * @work is guaranteed to be queued immediately.
+ *
+ * Return: %false if @dwork was idle and queued, %true otherwise.
+ *
+ * A special case is when the work is being canceled in parallel.
+ * It might be caused either by the real kthread_cancel_delayed_work_sync()
+ * or yet another kthread_mod_delayed_work() call. We let the other command
+ * win and return %true here. The return value can be used for reference
+ * counting and the number of queued works stays the same. Anyway, the caller
+ * is supposed to synchronize these operations a reasonable way.
+ *
+ * This function is safe to call from any context including IRQ handler.
+ * See __kthread_cancel_work() and kthread_delayed_work_timer_fn()
+ * for details.
+ */
+bool kthread_mod_delayed_work(struct kthread_worker *worker,
+			      struct kthread_delayed_work *dwork,
+			      unsigned long delay)
+{
+	struct kthread_work *work = &dwork->work;
+	unsigned long flags;
+	int ret;
+
+	raw_spin_lock_irqsave(&worker->lock, flags);
+
+	/* Do not bother with canceling when never queued. */
+	if (!work->worker) {
+		ret = false;
+		goto fast_queue;
+	}
+
+	/* Work must not be used with >1 worker, see kthread_queue_work() */
+	WARN_ON_ONCE(work->worker != worker);
+
+	/*
+	 * Temporary cancel the work but do not fight with another command
+	 * that is canceling the work as well.
+	 *
+	 * It is a bit tricky because of possible races with another
+	 * mod_delayed_work() and cancel_delayed_work() callers.
+	 *
+	 * The timer must be canceled first because worker->lock is released
+	 * when doing so. But the work can be removed from the queue (list)
+	 * only when it can be queued again so that the return value can
+	 * be used for reference counting.
+	 */
+	kthread_cancel_delayed_work_timer(work, &flags);
+	if (work->canceling) {
+		/* The number of works in the queue does not change. */
+		ret = true;
+		goto out;
+	}
+	ret = __kthread_cancel_work(work);
+
+fast_queue:
+	__kthread_queue_delayed_work(worker, dwork, delay);
+out:
+	raw_spin_unlock_irqrestore(&worker->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kthread_mod_delayed_work);
+
+static bool __kthread_cancel_work_sync(struct kthread_work *work, bool is_dwork)
+{
+	struct kthread_worker *worker = work->worker;
+	unsigned long flags;
+	int ret = false;
+
+	if (!worker)
+		goto out;
+
+	raw_spin_lock_irqsave(&worker->lock, flags);
+	/* Work must not be used with >1 worker, see kthread_queue_work(). */
+	WARN_ON_ONCE(work->worker != worker);
+
+	if (is_dwork)
+		kthread_cancel_delayed_work_timer(work, &flags);
+
+	ret = __kthread_cancel_work(work);
+
+	if (worker->current_work != work)
+		goto out_fast;
+
+	/*
+	 * The work is in progress and we need to wait with the lock released.
+	 * In the meantime, block any queuing by setting the canceling counter.
+	 */
+	work->canceling++;
+	raw_spin_unlock_irqrestore(&worker->lock, flags);
+	kthread_flush_work(work);
+	raw_spin_lock_irqsave(&worker->lock, flags);
+	work->canceling--;
+
+out_fast:
+	raw_spin_unlock_irqrestore(&worker->lock, flags);
+out:
+	return ret;
+}
+
+/**
+ * kthread_cancel_work_sync - cancel a kthread work and wait for it to finish
+ * @work: the kthread work to cancel
+ *
+ * Cancel @work and wait for its execution to finish.  This function
+ * can be used even if the work re-queues itself. On return from this
+ * function, @work is guaranteed to be not pending or executing on any CPU.
+ *
+ * kthread_cancel_work_sync(&delayed_work->work) must not be used for
+ * delayed_work's. Use kthread_cancel_delayed_work_sync() instead.
+ *
+ * The caller must ensure that the worker on which @work was last
+ * queued can't be destroyed before this function returns.
+ *
+ * Return: %true if @work was pending, %false otherwise.
+ */
+bool kthread_cancel_work_sync(struct kthread_work *work)
+{
+	return __kthread_cancel_work_sync(work, false);
+}
+EXPORT_SYMBOL_GPL(kthread_cancel_work_sync);
+
+/**
+ * kthread_cancel_delayed_work_sync - cancel a kthread delayed work and
+ *	wait for it to finish.
+ * @dwork: the kthread delayed work to cancel
+ *
+ * This is kthread_cancel_work_sync() for delayed works.
+ *
+ * Return: %true if @dwork was pending, %false otherwise.
+ */
+bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *dwork)
+{
+	return __kthread_cancel_work_sync(&dwork->work, true);
+}
+EXPORT_SYMBOL_GPL(kthread_cancel_delayed_work_sync);
+
+/**
+ * kthread_flush_worker - flush all current works on a kthread_worker
+ * @worker: worker to flush
+ *
+ * Wait until all currently executing or pending works on @worker are
+ * finished.
+ */
+void kthread_flush_worker(struct kthread_worker *worker)
+{
+	struct kthread_flush_work fwork = {
+		KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),
+		COMPLETION_INITIALIZER_ONSTACK(fwork.done),
+	};
+
+	kthread_queue_work(worker, &fwork.work);
+	wait_for_completion(&fwork.done);
+}
+EXPORT_SYMBOL_GPL(kthread_flush_worker);
+
+/**
+ * kthread_destroy_worker - destroy a kthread worker
+ * @worker: worker to be destroyed
+ *
+ * Flush and destroy @worker.  The simple flush is enough because the kthread
+ * worker API is used only in trivial scenarios.  There are no multi-step state
+ * machines needed.
+ */
+void kthread_destroy_worker(struct kthread_worker *worker)
+{
+	struct task_struct *task;
+
+	task = worker->task;
+	if (WARN_ON(!task))
+		return;
+
+	kthread_flush_worker(worker);
+	kthread_stop(task);
+	WARN_ON(!list_empty(&worker->work_list));
+	kfree(worker);
+}
+EXPORT_SYMBOL(kthread_destroy_worker);
+
+/**
+ * kthread_use_mm - make the calling kthread operate on an address space
+ * @mm: address space to operate on
+ */
+void kthread_use_mm(struct mm_struct *mm)
+{
+	struct mm_struct *active_mm;
+	struct task_struct *tsk = current;
+
+	WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD));
+	WARN_ON_ONCE(tsk->mm);
+
+	task_lock(tsk);
+	/* Hold off tlb flush IPIs while switching mm's */
+	local_irq_disable();
+	active_mm = tsk->active_mm;
+	if (active_mm != mm) {
+		mmgrab(mm);
+		tsk->active_mm = mm;
+	}
+	tsk->mm = mm;
+	membarrier_update_current_mm(mm);
+	switch_mm_irqs_off(active_mm, mm, tsk);
+	local_irq_enable();
+	task_unlock(tsk);
+#ifdef finish_arch_post_lock_switch
+	finish_arch_post_lock_switch();
+#endif
+
+	/*
+	 * When a kthread starts operating on an address space, the loop
+	 * in membarrier_{private,global}_expedited() may not observe
+	 * that tsk->mm, and not issue an IPI. Membarrier requires a
+	 * memory barrier after storing to tsk->mm, before accessing
+	 * user-space memory. A full memory barrier for membarrier
+	 * {PRIVATE,GLOBAL}_EXPEDITED is implicitly provided by
+	 * mmdrop(), or explicitly with smp_mb().
+	 */
+	if (active_mm != mm)
+		mmdrop(active_mm);
+	else
+		smp_mb();
+}
+EXPORT_SYMBOL_GPL(kthread_use_mm);
+
+/**
+ * kthread_unuse_mm - reverse the effect of kthread_use_mm()
+ * @mm: address space to operate on
+ */
+void kthread_unuse_mm(struct mm_struct *mm)
+{
+	struct task_struct *tsk = current;
+
+	WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD));
+	WARN_ON_ONCE(!tsk->mm);
+
+	task_lock(tsk);
+	/*
+	 * When a kthread stops operating on an address space, the loop
+	 * in membarrier_{private,global}_expedited() may not observe
+	 * that tsk->mm, and not issue an IPI. Membarrier requires a
+	 * memory barrier after accessing user-space memory, before
+	 * clearing tsk->mm.
+	 */
+	smp_mb__after_spinlock();
+	sync_mm_rss(mm);
+	local_irq_disable();
+	tsk->mm = NULL;
+	membarrier_update_current_mm(NULL);
+	/* active_mm is still 'mm' */
+	enter_lazy_tlb(mm, tsk);
+	local_irq_enable();
+	task_unlock(tsk);
+}
+EXPORT_SYMBOL_GPL(kthread_unuse_mm);
+
+#ifdef CONFIG_BLK_CGROUP
+/**
+ * kthread_associate_blkcg - associate blkcg to current kthread
+ * @css: the cgroup info
+ *
+ * Current thread must be a kthread. The thread is running jobs on behalf of
+ * other threads. In some cases, we expect the jobs attach cgroup info of
+ * original threads instead of that of current thread. This function stores
+ * original thread's cgroup info in current kthread context for later
+ * retrieval.
+ */
+void kthread_associate_blkcg(struct cgroup_subsys_state *css)
+{
+	struct kthread *kthread;
+
+	if (!(current->flags & PF_KTHREAD))
+		return;
+	kthread = to_kthread(current);
+	if (!kthread)
+		return;
+
+	if (kthread->blkcg_css) {
+		css_put(kthread->blkcg_css);
+		kthread->blkcg_css = NULL;
+	}
+	if (css) {
+		css_get(css);
+		kthread->blkcg_css = css;
+	}
+}
+EXPORT_SYMBOL(kthread_associate_blkcg);
+
+/**
+ * kthread_blkcg - get associated blkcg css of current kthread
+ *
+ * Current thread must be a kthread.
+ */
+struct cgroup_subsys_state *kthread_blkcg(void)
+{
+	struct kthread *kthread;
+
+	if (current->flags & PF_KTHREAD) {
+		kthread = to_kthread(current);
+		if (kthread)
+			return kthread->blkcg_css;
+	}
+	return NULL;
+}
+#endif
diff --git a/kernel/latencytop.c b/kernel/latencytop.c
new file mode 100644
index 000000000..781249098
--- /dev/null
+++ b/kernel/latencytop.c
@@ -0,0 +1,300 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * latencytop.c: Latency display infrastructure
+ *
+ * (C) Copyright 2008 Intel Corporation
+ * Author: Arjan van de Ven <arjan@linux.intel.com>
+ */
+
+/*
+ * CONFIG_LATENCYTOP enables a kernel latency tracking infrastructure that is
+ * used by the "latencytop" userspace tool. The latency that is tracked is not
+ * the 'traditional' interrupt latency (which is primarily caused by something
+ * else consuming CPU), but instead, it is the latency an application encounters
+ * because the kernel sleeps on its behalf for various reasons.
+ *
+ * This code tracks 2 levels of statistics:
+ * 1) System level latency
+ * 2) Per process latency
+ *
+ * The latency is stored in fixed sized data structures in an accumulated form;
+ * if the "same" latency cause is hit twice, this will be tracked as one entry
+ * in the data structure. Both the count, total accumulated latency and maximum
+ * latency are tracked in this data structure. When the fixed size structure is
+ * full, no new causes are tracked until the buffer is flushed by writing to
+ * the /proc file; the userspace tool does this on a regular basis.
+ *
+ * A latency cause is identified by a stringified backtrace at the point that
+ * the scheduler gets invoked. The userland tool will use this string to
+ * identify the cause of the latency in human readable form.
+ *
+ * The information is exported via /proc/latency_stats and /proc/<pid>/latency.
+ * These files look like this:
+ *
+ * Latency Top version : v0.1
+ * 70 59433 4897 i915_irq_wait drm_ioctl vfs_ioctl do_vfs_ioctl sys_ioctl
+ * |    |    |    |
+ * |    |    |    +----> the stringified backtrace
+ * |    |    +---------> The maximum latency for this entry in microseconds
+ * |    +--------------> The accumulated latency for this entry (microseconds)
+ * +-------------------> The number of times this entry is hit
+ *
+ * (note: the average latency is the accumulated latency divided by the number
+ * of times)
+ */
+
+#include <linux/kallsyms.h>
+#include <linux/seq_file.h>
+#include <linux/notifier.h>
+#include <linux/spinlock.h>
+#include <linux/proc_fs.h>
+#include <linux/latencytop.h>
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/stat.h>
+#include <linux/list.h>
+#include <linux/stacktrace.h>
+#include <linux/sysctl.h>
+
+static DEFINE_RAW_SPINLOCK(latency_lock);
+
+#define MAXLR 128
+static struct latency_record latency_record[MAXLR];
+
+int latencytop_enabled;
+
+#ifdef CONFIG_SYSCTL
+static int sysctl_latencytop(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	int err;
+
+	err = proc_dointvec(table, write, buffer, lenp, ppos);
+	if (latencytop_enabled)
+		force_schedstat_enabled();
+
+	return err;
+}
+
+static struct ctl_table latencytop_sysctl[] = {
+	{
+		.procname   = "latencytop",
+		.data       = &latencytop_enabled,
+		.maxlen     = sizeof(int),
+		.mode       = 0644,
+		.proc_handler   = sysctl_latencytop,
+	},
+	{}
+};
+#endif
+
+void clear_tsk_latency_tracing(struct task_struct *p)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&latency_lock, flags);
+	memset(&p->latency_record, 0, sizeof(p->latency_record));
+	p->latency_record_count = 0;
+	raw_spin_unlock_irqrestore(&latency_lock, flags);
+}
+
+static void clear_global_latency_tracing(void)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&latency_lock, flags);
+	memset(&latency_record, 0, sizeof(latency_record));
+	raw_spin_unlock_irqrestore(&latency_lock, flags);
+}
+
+static void __sched
+account_global_scheduler_latency(struct task_struct *tsk,
+				 struct latency_record *lat)
+{
+	int firstnonnull = MAXLR;
+	int i;
+
+	/* skip kernel threads for now */
+	if (!tsk->mm)
+		return;
+
+	for (i = 0; i < MAXLR; i++) {
+		int q, same = 1;
+
+		/* Nothing stored: */
+		if (!latency_record[i].backtrace[0]) {
+			if (firstnonnull > i)
+				firstnonnull = i;
+			continue;
+		}
+		for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
+			unsigned long record = lat->backtrace[q];
+
+			if (latency_record[i].backtrace[q] != record) {
+				same = 0;
+				break;
+			}
+
+			/* 0 entry marks end of backtrace: */
+			if (!record)
+				break;
+		}
+		if (same) {
+			latency_record[i].count++;
+			latency_record[i].time += lat->time;
+			if (lat->time > latency_record[i].max)
+				latency_record[i].max = lat->time;
+			return;
+		}
+	}
+
+	i = firstnonnull;
+	if (i >= MAXLR)
+		return;
+
+	/* Allocted a new one: */
+	memcpy(&latency_record[i], lat, sizeof(struct latency_record));
+}
+
+/**
+ * __account_scheduler_latency - record an occurred latency
+ * @tsk - the task struct of the task hitting the latency
+ * @usecs - the duration of the latency in microseconds
+ * @inter - 1 if the sleep was interruptible, 0 if uninterruptible
+ *
+ * This function is the main entry point for recording latency entries
+ * as called by the scheduler.
+ *
+ * This function has a few special cases to deal with normal 'non-latency'
+ * sleeps: specifically, interruptible sleep longer than 5 msec is skipped
+ * since this usually is caused by waiting for events via select() and co.
+ *
+ * Negative latencies (caused by time going backwards) are also explicitly
+ * skipped.
+ */
+void __sched
+__account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
+{
+	unsigned long flags;
+	int i, q;
+	struct latency_record lat;
+
+	/* Long interruptible waits are generally user requested... */
+	if (inter && usecs > 5000)
+		return;
+
+	/* Negative sleeps are time going backwards */
+	/* Zero-time sleeps are non-interesting */
+	if (usecs <= 0)
+		return;
+
+	memset(&lat, 0, sizeof(lat));
+	lat.count = 1;
+	lat.time = usecs;
+	lat.max = usecs;
+
+	stack_trace_save_tsk(tsk, lat.backtrace, LT_BACKTRACEDEPTH, 0);
+
+	raw_spin_lock_irqsave(&latency_lock, flags);
+
+	account_global_scheduler_latency(tsk, &lat);
+
+	for (i = 0; i < tsk->latency_record_count; i++) {
+		struct latency_record *mylat;
+		int same = 1;
+
+		mylat = &tsk->latency_record[i];
+		for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
+			unsigned long record = lat.backtrace[q];
+
+			if (mylat->backtrace[q] != record) {
+				same = 0;
+				break;
+			}
+
+			/* 0 entry is end of backtrace */
+			if (!record)
+				break;
+		}
+		if (same) {
+			mylat->count++;
+			mylat->time += lat.time;
+			if (lat.time > mylat->max)
+				mylat->max = lat.time;
+			goto out_unlock;
+		}
+	}
+
+	/*
+	 * short term hack; if we're > 32 we stop; future we recycle:
+	 */
+	if (tsk->latency_record_count >= LT_SAVECOUNT)
+		goto out_unlock;
+
+	/* Allocated a new one: */
+	i = tsk->latency_record_count++;
+	memcpy(&tsk->latency_record[i], &lat, sizeof(struct latency_record));
+
+out_unlock:
+	raw_spin_unlock_irqrestore(&latency_lock, flags);
+}
+
+static int lstats_show(struct seq_file *m, void *v)
+{
+	int i;
+
+	seq_puts(m, "Latency Top version : v0.1\n");
+
+	for (i = 0; i < MAXLR; i++) {
+		struct latency_record *lr = &latency_record[i];
+
+		if (lr->backtrace[0]) {
+			int q;
+			seq_printf(m, "%i %lu %lu",
+				   lr->count, lr->time, lr->max);
+			for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
+				unsigned long bt = lr->backtrace[q];
+
+				if (!bt)
+					break;
+
+				seq_printf(m, " %ps", (void *)bt);
+			}
+			seq_puts(m, "\n");
+		}
+	}
+	return 0;
+}
+
+static ssize_t
+lstats_write(struct file *file, const char __user *buf, size_t count,
+	     loff_t *offs)
+{
+	clear_global_latency_tracing();
+
+	return count;
+}
+
+static int lstats_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, lstats_show, NULL);
+}
+
+static const struct proc_ops lstats_proc_ops = {
+	.proc_open	= lstats_open,
+	.proc_read	= seq_read,
+	.proc_write	= lstats_write,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= single_release,
+};
+
+static int __init init_lstats_procfs(void)
+{
+	proc_create("latency_stats", 0644, NULL, &lstats_proc_ops);
+#ifdef CONFIG_SYSCTL
+	register_sysctl_init("kernel", latencytop_sysctl);
+#endif
+	return 0;
+}
+device_initcall(init_lstats_procfs);
diff --git a/kernel/livepatch/Kconfig b/kernel/livepatch/Kconfig
new file mode 100644
index 000000000..53d51ed61
--- /dev/null
+++ b/kernel/livepatch/Kconfig
@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config HAVE_LIVEPATCH
+	bool
+	help
+	  Arch supports kernel live patching
+
+config LIVEPATCH
+	bool "Kernel Live Patching"
+	depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS
+	depends on MODULES
+	depends on SYSFS
+	depends on KALLSYMS_ALL
+	depends on HAVE_LIVEPATCH
+	depends on !TRIM_UNUSED_KSYMS
+	help
+	  Say Y here if you want to support kernel live patching.
+	  This option has no runtime impact until a kernel "patch"
+	  module uses the interface provided by this option to register
+	  a patch, causing calls to patched functions to be redirected
+	  to new function code contained in the patch module.
diff --git a/kernel/livepatch/Makefile b/kernel/livepatch/Makefile
new file mode 100644
index 000000000..cf03d4bdf
--- /dev/null
+++ b/kernel/livepatch/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_LIVEPATCH) += livepatch.o
+
+livepatch-objs := core.o patch.o shadow.o state.o transition.o
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
new file mode 100644
index 000000000..0e651fd4c
--- /dev/null
+++ b/kernel/livepatch/core.c
@@ -0,0 +1,1291 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * core.c - Kernel Live Patching Core
+ *
+ * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
+ * Copyright (C) 2014 SUSE
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/kallsyms.h>
+#include <linux/livepatch.h>
+#include <linux/elf.h>
+#include <linux/moduleloader.h>
+#include <linux/completion.h>
+#include <linux/memory.h>
+#include <linux/rcupdate.h>
+#include <asm/cacheflush.h>
+#include "core.h"
+#include "patch.h"
+#include "state.h"
+#include "transition.h"
+
+/*
+ * klp_mutex is a coarse lock which serializes access to klp data.  All
+ * accesses to klp-related variables and structures must have mutex protection,
+ * except within the following functions which carefully avoid the need for it:
+ *
+ * - klp_ftrace_handler()
+ * - klp_update_patch_state()
+ */
+DEFINE_MUTEX(klp_mutex);
+
+/*
+ * Actively used patches: enabled or in transition. Note that replaced
+ * or disabled patches are not listed even though the related kernel
+ * module still can be loaded.
+ */
+LIST_HEAD(klp_patches);
+
+static struct kobject *klp_root_kobj;
+
+static bool klp_is_module(struct klp_object *obj)
+{
+	return obj->name;
+}
+
+/* sets obj->mod if object is not vmlinux and module is found */
+static void klp_find_object_module(struct klp_object *obj)
+{
+	struct module *mod;
+
+	if (!klp_is_module(obj))
+		return;
+
+	rcu_read_lock_sched();
+	/*
+	 * We do not want to block removal of patched modules and therefore
+	 * we do not take a reference here. The patches are removed by
+	 * klp_module_going() instead.
+	 */
+	mod = find_module(obj->name);
+	/*
+	 * Do not mess work of klp_module_coming() and klp_module_going().
+	 * Note that the patch might still be needed before klp_module_going()
+	 * is called. Module functions can be called even in the GOING state
+	 * until mod->exit() finishes. This is especially important for
+	 * patches that modify semantic of the functions.
+	 */
+	if (mod && mod->klp_alive)
+		obj->mod = mod;
+
+	rcu_read_unlock_sched();
+}
+
+static bool klp_initialized(void)
+{
+	return !!klp_root_kobj;
+}
+
+static struct klp_func *klp_find_func(struct klp_object *obj,
+				      struct klp_func *old_func)
+{
+	struct klp_func *func;
+
+	klp_for_each_func(obj, func) {
+		if ((strcmp(old_func->old_name, func->old_name) == 0) &&
+		    (old_func->old_sympos == func->old_sympos)) {
+			return func;
+		}
+	}
+
+	return NULL;
+}
+
+static struct klp_object *klp_find_object(struct klp_patch *patch,
+					  struct klp_object *old_obj)
+{
+	struct klp_object *obj;
+
+	klp_for_each_object(patch, obj) {
+		if (klp_is_module(old_obj)) {
+			if (klp_is_module(obj) &&
+			    strcmp(old_obj->name, obj->name) == 0) {
+				return obj;
+			}
+		} else if (!klp_is_module(obj)) {
+			return obj;
+		}
+	}
+
+	return NULL;
+}
+
+struct klp_find_arg {
+	const char *objname;
+	const char *name;
+	unsigned long addr;
+	unsigned long count;
+	unsigned long pos;
+};
+
+static int klp_find_callback(void *data, const char *name,
+			     struct module *mod, unsigned long addr)
+{
+	struct klp_find_arg *args = data;
+
+	if ((mod && !args->objname) || (!mod && args->objname))
+		return 0;
+
+	if (strcmp(args->name, name))
+		return 0;
+
+	if (args->objname && strcmp(args->objname, mod->name))
+		return 0;
+
+	args->addr = addr;
+	args->count++;
+
+	/*
+	 * Finish the search when the symbol is found for the desired position
+	 * or the position is not defined for a non-unique symbol.
+	 */
+	if ((args->pos && (args->count == args->pos)) ||
+	    (!args->pos && (args->count > 1)))
+		return 1;
+
+	return 0;
+}
+
+static int klp_find_object_symbol(const char *objname, const char *name,
+				  unsigned long sympos, unsigned long *addr)
+{
+	struct klp_find_arg args = {
+		.objname = objname,
+		.name = name,
+		.addr = 0,
+		.count = 0,
+		.pos = sympos,
+	};
+
+	if (objname)
+		module_kallsyms_on_each_symbol(klp_find_callback, &args);
+	else
+		kallsyms_on_each_symbol(klp_find_callback, &args);
+
+	/*
+	 * Ensure an address was found. If sympos is 0, ensure symbol is unique;
+	 * otherwise ensure the symbol position count matches sympos.
+	 */
+	if (args.addr == 0)
+		pr_err("symbol '%s' not found in symbol table\n", name);
+	else if (args.count > 1 && sympos == 0) {
+		pr_err("unresolvable ambiguity for symbol '%s' in object '%s'\n",
+		       name, objname);
+	} else if (sympos != args.count && sympos > 0) {
+		pr_err("symbol position %lu for symbol '%s' in object '%s' not found\n",
+		       sympos, name, objname ? objname : "vmlinux");
+	} else {
+		*addr = args.addr;
+		return 0;
+	}
+
+	*addr = 0;
+	return -EINVAL;
+}
+
+static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
+			       unsigned int symndx, Elf_Shdr *relasec,
+			       const char *sec_objname)
+{
+	int i, cnt, ret;
+	char sym_objname[MODULE_NAME_LEN];
+	char sym_name[KSYM_NAME_LEN];
+	Elf_Rela *relas;
+	Elf_Sym *sym;
+	unsigned long sympos, addr;
+	bool sym_vmlinux;
+	bool sec_vmlinux = !strcmp(sec_objname, "vmlinux");
+
+	/*
+	 * Since the field widths for sym_objname and sym_name in the sscanf()
+	 * call are hard-coded and correspond to MODULE_NAME_LEN and
+	 * KSYM_NAME_LEN respectively, we must make sure that MODULE_NAME_LEN
+	 * and KSYM_NAME_LEN have the values we expect them to have.
+	 *
+	 * Because the value of MODULE_NAME_LEN can differ among architectures,
+	 * we use the smallest/strictest upper bound possible (56, based on
+	 * the current definition of MODULE_NAME_LEN) to prevent overflows.
+	 */
+	BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 512);
+
+	relas = (Elf_Rela *) relasec->sh_addr;
+	/* For each rela in this klp relocation section */
+	for (i = 0; i < relasec->sh_size / sizeof(Elf_Rela); i++) {
+		sym = (Elf_Sym *)sechdrs[symndx].sh_addr + ELF_R_SYM(relas[i].r_info);
+		if (sym->st_shndx != SHN_LIVEPATCH) {
+			pr_err("symbol %s is not marked as a livepatch symbol\n",
+			       strtab + sym->st_name);
+			return -EINVAL;
+		}
+
+		/* Format: .klp.sym.sym_objname.sym_name,sympos */
+		cnt = sscanf(strtab + sym->st_name,
+			     ".klp.sym.%55[^.].%511[^,],%lu",
+			     sym_objname, sym_name, &sympos);
+		if (cnt != 3) {
+			pr_err("symbol %s has an incorrectly formatted name\n",
+			       strtab + sym->st_name);
+			return -EINVAL;
+		}
+
+		sym_vmlinux = !strcmp(sym_objname, "vmlinux");
+
+		/*
+		 * Prevent module-specific KLP rela sections from referencing
+		 * vmlinux symbols.  This helps prevent ordering issues with
+		 * module special section initializations.  Presumably such
+		 * symbols are exported and normal relas can be used instead.
+		 */
+		if (!sec_vmlinux && sym_vmlinux) {
+			pr_err("invalid access to vmlinux symbol '%s' from module-specific livepatch relocation section\n",
+			       sym_name);
+			return -EINVAL;
+		}
+
+		/* klp_find_object_symbol() treats a NULL objname as vmlinux */
+		ret = klp_find_object_symbol(sym_vmlinux ? NULL : sym_objname,
+					     sym_name, sympos, &addr);
+		if (ret)
+			return ret;
+
+		sym->st_value = addr;
+	}
+
+	return 0;
+}
+
+/*
+ * At a high-level, there are two types of klp relocation sections: those which
+ * reference symbols which live in vmlinux; and those which reference symbols
+ * which live in other modules.  This function is called for both types:
+ *
+ * 1) When a klp module itself loads, the module code calls this function to
+ *    write vmlinux-specific klp relocations (.klp.rela.vmlinux.* sections).
+ *    These relocations are written to the klp module text to allow the patched
+ *    code/data to reference unexported vmlinux symbols.  They're written as
+ *    early as possible to ensure that other module init code (.e.g.,
+ *    jump_label_apply_nops) can access any unexported vmlinux symbols which
+ *    might be referenced by the klp module's special sections.
+ *
+ * 2) When a to-be-patched module loads -- or is already loaded when a
+ *    corresponding klp module loads -- klp code calls this function to write
+ *    module-specific klp relocations (.klp.rela.{module}.* sections).  These
+ *    are written to the klp module text to allow the patched code/data to
+ *    reference symbols which live in the to-be-patched module or one of its
+ *    module dependencies.  Exported symbols are supported, in addition to
+ *    unexported symbols, in order to enable late module patching, which allows
+ *    the to-be-patched module to be loaded and patched sometime *after* the
+ *    klp module is loaded.
+ */
+int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
+			     const char *shstrtab, const char *strtab,
+			     unsigned int symndx, unsigned int secndx,
+			     const char *objname)
+{
+	int cnt, ret;
+	char sec_objname[MODULE_NAME_LEN];
+	Elf_Shdr *sec = sechdrs + secndx;
+
+	/*
+	 * Format: .klp.rela.sec_objname.section_name
+	 * See comment in klp_resolve_symbols() for an explanation
+	 * of the selected field width value.
+	 */
+	cnt = sscanf(shstrtab + sec->sh_name, ".klp.rela.%55[^.]",
+		     sec_objname);
+	if (cnt != 1) {
+		pr_err("section %s has an incorrectly formatted name\n",
+		       shstrtab + sec->sh_name);
+		return -EINVAL;
+	}
+
+	if (strcmp(objname ? objname : "vmlinux", sec_objname))
+		return 0;
+
+	ret = klp_resolve_symbols(sechdrs, strtab, symndx, sec, sec_objname);
+	if (ret)
+		return ret;
+
+	return apply_relocate_add(sechdrs, strtab, symndx, secndx, pmod);
+}
+
+/*
+ * Sysfs Interface
+ *
+ * /sys/kernel/livepatch
+ * /sys/kernel/livepatch/<patch>
+ * /sys/kernel/livepatch/<patch>/enabled
+ * /sys/kernel/livepatch/<patch>/transition
+ * /sys/kernel/livepatch/<patch>/force
+ * /sys/kernel/livepatch/<patch>/<object>
+ * /sys/kernel/livepatch/<patch>/<object>/patched
+ * /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
+ */
+static int __klp_disable_patch(struct klp_patch *patch);
+
+static ssize_t enabled_store(struct kobject *kobj, struct kobj_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct klp_patch *patch;
+	int ret;
+	bool enabled;
+
+	ret = kstrtobool(buf, &enabled);
+	if (ret)
+		return ret;
+
+	patch = container_of(kobj, struct klp_patch, kobj);
+
+	mutex_lock(&klp_mutex);
+
+	if (patch->enabled == enabled) {
+		/* already in requested state */
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Allow to reverse a pending transition in both ways. It might be
+	 * necessary to complete the transition without forcing and breaking
+	 * the system integrity.
+	 *
+	 * Do not allow to re-enable a disabled patch.
+	 */
+	if (patch == klp_transition_patch)
+		klp_reverse_transition();
+	else if (!enabled)
+		ret = __klp_disable_patch(patch);
+	else
+		ret = -EINVAL;
+
+out:
+	mutex_unlock(&klp_mutex);
+
+	if (ret)
+		return ret;
+	return count;
+}
+
+static ssize_t enabled_show(struct kobject *kobj,
+			    struct kobj_attribute *attr, char *buf)
+{
+	struct klp_patch *patch;
+
+	patch = container_of(kobj, struct klp_patch, kobj);
+	return snprintf(buf, PAGE_SIZE-1, "%d\n", patch->enabled);
+}
+
+static ssize_t transition_show(struct kobject *kobj,
+			       struct kobj_attribute *attr, char *buf)
+{
+	struct klp_patch *patch;
+
+	patch = container_of(kobj, struct klp_patch, kobj);
+	return snprintf(buf, PAGE_SIZE-1, "%d\n",
+			patch == klp_transition_patch);
+}
+
+static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
+			   const char *buf, size_t count)
+{
+	struct klp_patch *patch;
+	int ret;
+	bool val;
+
+	ret = kstrtobool(buf, &val);
+	if (ret)
+		return ret;
+
+	if (!val)
+		return count;
+
+	mutex_lock(&klp_mutex);
+
+	patch = container_of(kobj, struct klp_patch, kobj);
+	if (patch != klp_transition_patch) {
+		mutex_unlock(&klp_mutex);
+		return -EINVAL;
+	}
+
+	klp_force_transition();
+
+	mutex_unlock(&klp_mutex);
+
+	return count;
+}
+
+static struct kobj_attribute enabled_kobj_attr = __ATTR_RW(enabled);
+static struct kobj_attribute transition_kobj_attr = __ATTR_RO(transition);
+static struct kobj_attribute force_kobj_attr = __ATTR_WO(force);
+static struct attribute *klp_patch_attrs[] = {
+	&enabled_kobj_attr.attr,
+	&transition_kobj_attr.attr,
+	&force_kobj_attr.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(klp_patch);
+
+static ssize_t patched_show(struct kobject *kobj,
+			    struct kobj_attribute *attr, char *buf)
+{
+	struct klp_object *obj;
+
+	obj = container_of(kobj, struct klp_object, kobj);
+	return sysfs_emit(buf, "%d\n", obj->patched);
+}
+
+static struct kobj_attribute patched_kobj_attr = __ATTR_RO(patched);
+static struct attribute *klp_object_attrs[] = {
+	&patched_kobj_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(klp_object);
+
+static void klp_free_object_dynamic(struct klp_object *obj)
+{
+	kfree(obj->name);
+	kfree(obj);
+}
+
+static void klp_init_func_early(struct klp_object *obj,
+				struct klp_func *func);
+static void klp_init_object_early(struct klp_patch *patch,
+				  struct klp_object *obj);
+
+static struct klp_object *klp_alloc_object_dynamic(const char *name,
+						   struct klp_patch *patch)
+{
+	struct klp_object *obj;
+
+	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
+	if (!obj)
+		return NULL;
+
+	if (name) {
+		obj->name = kstrdup(name, GFP_KERNEL);
+		if (!obj->name) {
+			kfree(obj);
+			return NULL;
+		}
+	}
+
+	klp_init_object_early(patch, obj);
+	obj->dynamic = true;
+
+	return obj;
+}
+
+static void klp_free_func_nop(struct klp_func *func)
+{
+	kfree(func->old_name);
+	kfree(func);
+}
+
+static struct klp_func *klp_alloc_func_nop(struct klp_func *old_func,
+					   struct klp_object *obj)
+{
+	struct klp_func *func;
+
+	func = kzalloc(sizeof(*func), GFP_KERNEL);
+	if (!func)
+		return NULL;
+
+	if (old_func->old_name) {
+		func->old_name = kstrdup(old_func->old_name, GFP_KERNEL);
+		if (!func->old_name) {
+			kfree(func);
+			return NULL;
+		}
+	}
+
+	klp_init_func_early(obj, func);
+	/*
+	 * func->new_func is same as func->old_func. These addresses are
+	 * set when the object is loaded, see klp_init_object_loaded().
+	 */
+	func->old_sympos = old_func->old_sympos;
+	func->nop = true;
+
+	return func;
+}
+
+static int klp_add_object_nops(struct klp_patch *patch,
+			       struct klp_object *old_obj)
+{
+	struct klp_object *obj;
+	struct klp_func *func, *old_func;
+
+	obj = klp_find_object(patch, old_obj);
+
+	if (!obj) {
+		obj = klp_alloc_object_dynamic(old_obj->name, patch);
+		if (!obj)
+			return -ENOMEM;
+	}
+
+	klp_for_each_func(old_obj, old_func) {
+		func = klp_find_func(obj, old_func);
+		if (func)
+			continue;
+
+		func = klp_alloc_func_nop(old_func, obj);
+		if (!func)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/*
+ * Add 'nop' functions which simply return to the caller to run
+ * the original function. The 'nop' functions are added to a
+ * patch to facilitate a 'replace' mode.
+ */
+static int klp_add_nops(struct klp_patch *patch)
+{
+	struct klp_patch *old_patch;
+	struct klp_object *old_obj;
+
+	klp_for_each_patch(old_patch) {
+		klp_for_each_object(old_patch, old_obj) {
+			int err;
+
+			err = klp_add_object_nops(patch, old_obj);
+			if (err)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+static void klp_kobj_release_patch(struct kobject *kobj)
+{
+	struct klp_patch *patch;
+
+	patch = container_of(kobj, struct klp_patch, kobj);
+	complete(&patch->finish);
+}
+
+static struct kobj_type klp_ktype_patch = {
+	.release = klp_kobj_release_patch,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = klp_patch_groups,
+};
+
+static void klp_kobj_release_object(struct kobject *kobj)
+{
+	struct klp_object *obj;
+
+	obj = container_of(kobj, struct klp_object, kobj);
+
+	if (obj->dynamic)
+		klp_free_object_dynamic(obj);
+}
+
+static struct kobj_type klp_ktype_object = {
+	.release = klp_kobj_release_object,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = klp_object_groups,
+};
+
+static void klp_kobj_release_func(struct kobject *kobj)
+{
+	struct klp_func *func;
+
+	func = container_of(kobj, struct klp_func, kobj);
+
+	if (func->nop)
+		klp_free_func_nop(func);
+}
+
+static struct kobj_type klp_ktype_func = {
+	.release = klp_kobj_release_func,
+	.sysfs_ops = &kobj_sysfs_ops,
+};
+
+static void __klp_free_funcs(struct klp_object *obj, bool nops_only)
+{
+	struct klp_func *func, *tmp_func;
+
+	klp_for_each_func_safe(obj, func, tmp_func) {
+		if (nops_only && !func->nop)
+			continue;
+
+		list_del(&func->node);
+		kobject_put(&func->kobj);
+	}
+}
+
+/* Clean up when a patched object is unloaded */
+static void klp_free_object_loaded(struct klp_object *obj)
+{
+	struct klp_func *func;
+
+	obj->mod = NULL;
+
+	klp_for_each_func(obj, func) {
+		func->old_func = NULL;
+
+		if (func->nop)
+			func->new_func = NULL;
+	}
+}
+
+static void __klp_free_objects(struct klp_patch *patch, bool nops_only)
+{
+	struct klp_object *obj, *tmp_obj;
+
+	klp_for_each_object_safe(patch, obj, tmp_obj) {
+		__klp_free_funcs(obj, nops_only);
+
+		if (nops_only && !obj->dynamic)
+			continue;
+
+		list_del(&obj->node);
+		kobject_put(&obj->kobj);
+	}
+}
+
+static void klp_free_objects(struct klp_patch *patch)
+{
+	__klp_free_objects(patch, false);
+}
+
+static void klp_free_objects_dynamic(struct klp_patch *patch)
+{
+	__klp_free_objects(patch, true);
+}
+
+/*
+ * This function implements the free operations that can be called safely
+ * under klp_mutex.
+ *
+ * The operation must be completed by calling klp_free_patch_finish()
+ * outside klp_mutex.
+ */
+static void klp_free_patch_start(struct klp_patch *patch)
+{
+	if (!list_empty(&patch->list))
+		list_del(&patch->list);
+
+	klp_free_objects(patch);
+}
+
+/*
+ * This function implements the free part that must be called outside
+ * klp_mutex.
+ *
+ * It must be called after klp_free_patch_start(). And it has to be
+ * the last function accessing the livepatch structures when the patch
+ * gets disabled.
+ */
+static void klp_free_patch_finish(struct klp_patch *patch)
+{
+	/*
+	 * Avoid deadlock with enabled_store() sysfs callback by
+	 * calling this outside klp_mutex. It is safe because
+	 * this is called when the patch gets disabled and it
+	 * cannot get enabled again.
+	 */
+	kobject_put(&patch->kobj);
+	wait_for_completion(&patch->finish);
+
+	/* Put the module after the last access to struct klp_patch. */
+	if (!patch->forced)
+		module_put(patch->mod);
+}
+
+/*
+ * The livepatch might be freed from sysfs interface created by the patch.
+ * This work allows to wait until the interface is destroyed in a separate
+ * context.
+ */
+static void klp_free_patch_work_fn(struct work_struct *work)
+{
+	struct klp_patch *patch =
+		container_of(work, struct klp_patch, free_work);
+
+	klp_free_patch_finish(patch);
+}
+
+void klp_free_patch_async(struct klp_patch *patch)
+{
+	klp_free_patch_start(patch);
+	schedule_work(&patch->free_work);
+}
+
+void klp_free_replaced_patches_async(struct klp_patch *new_patch)
+{
+	struct klp_patch *old_patch, *tmp_patch;
+
+	klp_for_each_patch_safe(old_patch, tmp_patch) {
+		if (old_patch == new_patch)
+			return;
+		klp_free_patch_async(old_patch);
+	}
+}
+
+static int klp_init_func(struct klp_object *obj, struct klp_func *func)
+{
+	if (!func->old_name)
+		return -EINVAL;
+
+	/*
+	 * NOPs get the address later. The patched module must be loaded,
+	 * see klp_init_object_loaded().
+	 */
+	if (!func->new_func && !func->nop)
+		return -EINVAL;
+
+	if (strlen(func->old_name) >= KSYM_NAME_LEN)
+		return -EINVAL;
+
+	INIT_LIST_HEAD(&func->stack_node);
+	func->patched = false;
+	func->transition = false;
+
+	/* The format for the sysfs directory is <function,sympos> where sympos
+	 * is the nth occurrence of this symbol in kallsyms for the patched
+	 * object. If the user selects 0 for old_sympos, then 1 will be used
+	 * since a unique symbol will be the first occurrence.
+	 */
+	return kobject_add(&func->kobj, &obj->kobj, "%s,%lu",
+			   func->old_name,
+			   func->old_sympos ? func->old_sympos : 1);
+}
+
+static int klp_apply_object_relocs(struct klp_patch *patch,
+				   struct klp_object *obj)
+{
+	int i, ret;
+	struct klp_modinfo *info = patch->mod->klp_info;
+
+	for (i = 1; i < info->hdr.e_shnum; i++) {
+		Elf_Shdr *sec = info->sechdrs + i;
+
+		if (!(sec->sh_flags & SHF_RELA_LIVEPATCH))
+			continue;
+
+		ret = klp_apply_section_relocs(patch->mod, info->sechdrs,
+					       info->secstrings,
+					       patch->mod->core_kallsyms.strtab,
+					       info->symndx, i, obj->name);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+/* parts of the initialization that is done only when the object is loaded */
+static int klp_init_object_loaded(struct klp_patch *patch,
+				  struct klp_object *obj)
+{
+	struct klp_func *func;
+	int ret;
+
+	if (klp_is_module(obj)) {
+		/*
+		 * Only write module-specific relocations here
+		 * (.klp.rela.{module}.*).  vmlinux-specific relocations were
+		 * written earlier during the initialization of the klp module
+		 * itself.
+		 */
+		ret = klp_apply_object_relocs(patch, obj);
+		if (ret)
+			return ret;
+	}
+
+	klp_for_each_func(obj, func) {
+		ret = klp_find_object_symbol(obj->name, func->old_name,
+					     func->old_sympos,
+					     (unsigned long *)&func->old_func);
+		if (ret)
+			return ret;
+
+		ret = kallsyms_lookup_size_offset((unsigned long)func->old_func,
+						  &func->old_size, NULL);
+		if (!ret) {
+			pr_err("kallsyms size lookup failed for '%s'\n",
+			       func->old_name);
+			return -ENOENT;
+		}
+
+		if (func->nop)
+			func->new_func = func->old_func;
+
+		ret = kallsyms_lookup_size_offset((unsigned long)func->new_func,
+						  &func->new_size, NULL);
+		if (!ret) {
+			pr_err("kallsyms size lookup failed for '%s' replacement\n",
+			       func->old_name);
+			return -ENOENT;
+		}
+	}
+
+	return 0;
+}
+
+static int klp_init_object(struct klp_patch *patch, struct klp_object *obj)
+{
+	struct klp_func *func;
+	int ret;
+	const char *name;
+
+	if (klp_is_module(obj) && strlen(obj->name) >= MODULE_NAME_LEN)
+		return -EINVAL;
+
+	obj->patched = false;
+	obj->mod = NULL;
+
+	klp_find_object_module(obj);
+
+	name = klp_is_module(obj) ? obj->name : "vmlinux";
+	ret = kobject_add(&obj->kobj, &patch->kobj, "%s", name);
+	if (ret)
+		return ret;
+
+	klp_for_each_func(obj, func) {
+		ret = klp_init_func(obj, func);
+		if (ret)
+			return ret;
+	}
+
+	if (klp_is_object_loaded(obj))
+		ret = klp_init_object_loaded(patch, obj);
+
+	return ret;
+}
+
+static void klp_init_func_early(struct klp_object *obj,
+				struct klp_func *func)
+{
+	kobject_init(&func->kobj, &klp_ktype_func);
+	list_add_tail(&func->node, &obj->func_list);
+}
+
+static void klp_init_object_early(struct klp_patch *patch,
+				  struct klp_object *obj)
+{
+	INIT_LIST_HEAD(&obj->func_list);
+	kobject_init(&obj->kobj, &klp_ktype_object);
+	list_add_tail(&obj->node, &patch->obj_list);
+}
+
+static void klp_init_patch_early(struct klp_patch *patch)
+{
+	struct klp_object *obj;
+	struct klp_func *func;
+
+	INIT_LIST_HEAD(&patch->list);
+	INIT_LIST_HEAD(&patch->obj_list);
+	kobject_init(&patch->kobj, &klp_ktype_patch);
+	patch->enabled = false;
+	patch->forced = false;
+	INIT_WORK(&patch->free_work, klp_free_patch_work_fn);
+	init_completion(&patch->finish);
+
+	klp_for_each_object_static(patch, obj) {
+		klp_init_object_early(patch, obj);
+
+		klp_for_each_func_static(obj, func) {
+			klp_init_func_early(obj, func);
+		}
+	}
+}
+
+static int klp_init_patch(struct klp_patch *patch)
+{
+	struct klp_object *obj;
+	int ret;
+
+	ret = kobject_add(&patch->kobj, klp_root_kobj, "%s", patch->mod->name);
+	if (ret)
+		return ret;
+
+	if (patch->replace) {
+		ret = klp_add_nops(patch);
+		if (ret)
+			return ret;
+	}
+
+	klp_for_each_object(patch, obj) {
+		ret = klp_init_object(patch, obj);
+		if (ret)
+			return ret;
+	}
+
+	list_add_tail(&patch->list, &klp_patches);
+
+	return 0;
+}
+
+static int __klp_disable_patch(struct klp_patch *patch)
+{
+	struct klp_object *obj;
+
+	if (WARN_ON(!patch->enabled))
+		return -EINVAL;
+
+	if (klp_transition_patch)
+		return -EBUSY;
+
+	klp_init_transition(patch, KLP_UNPATCHED);
+
+	klp_for_each_object(patch, obj)
+		if (obj->patched)
+			klp_pre_unpatch_callback(obj);
+
+	/*
+	 * Enforce the order of the func->transition writes in
+	 * klp_init_transition() and the TIF_PATCH_PENDING writes in
+	 * klp_start_transition().  In the rare case where klp_ftrace_handler()
+	 * is called shortly after klp_update_patch_state() switches the task,
+	 * this ensures the handler sees that func->transition is set.
+	 */
+	smp_wmb();
+
+	klp_start_transition();
+	patch->enabled = false;
+	klp_try_complete_transition();
+
+	return 0;
+}
+
+static int __klp_enable_patch(struct klp_patch *patch)
+{
+	struct klp_object *obj;
+	int ret;
+
+	if (klp_transition_patch)
+		return -EBUSY;
+
+	if (WARN_ON(patch->enabled))
+		return -EINVAL;
+
+	pr_notice("enabling patch '%s'\n", patch->mod->name);
+
+	klp_init_transition(patch, KLP_PATCHED);
+
+	/*
+	 * Enforce the order of the func->transition writes in
+	 * klp_init_transition() and the ops->func_stack writes in
+	 * klp_patch_object(), so that klp_ftrace_handler() will see the
+	 * func->transition updates before the handler is registered and the
+	 * new funcs become visible to the handler.
+	 */
+	smp_wmb();
+
+	klp_for_each_object(patch, obj) {
+		if (!klp_is_object_loaded(obj))
+			continue;
+
+		ret = klp_pre_patch_callback(obj);
+		if (ret) {
+			pr_warn("pre-patch callback failed for object '%s'\n",
+				klp_is_module(obj) ? obj->name : "vmlinux");
+			goto err;
+		}
+
+		ret = klp_patch_object(obj);
+		if (ret) {
+			pr_warn("failed to patch object '%s'\n",
+				klp_is_module(obj) ? obj->name : "vmlinux");
+			goto err;
+		}
+	}
+
+	klp_start_transition();
+	patch->enabled = true;
+	klp_try_complete_transition();
+
+	return 0;
+err:
+	pr_warn("failed to enable patch '%s'\n", patch->mod->name);
+
+	klp_cancel_transition();
+	return ret;
+}
+
+/**
+ * klp_enable_patch() - enable the livepatch
+ * @patch:	patch to be enabled
+ *
+ * Initializes the data structure associated with the patch, creates the sysfs
+ * interface, performs the needed symbol lookups and code relocations,
+ * registers the patched functions with ftrace.
+ *
+ * This function is supposed to be called from the livepatch module_init()
+ * callback.
+ *
+ * Return: 0 on success, otherwise error
+ */
+int klp_enable_patch(struct klp_patch *patch)
+{
+	int ret;
+	struct klp_object *obj;
+
+	if (!patch || !patch->mod || !patch->objs)
+		return -EINVAL;
+
+	klp_for_each_object_static(patch, obj) {
+		if (!obj->funcs)
+			return -EINVAL;
+	}
+
+
+	if (!is_livepatch_module(patch->mod)) {
+		pr_err("module %s is not marked as a livepatch module\n",
+		       patch->mod->name);
+		return -EINVAL;
+	}
+
+	if (!klp_initialized())
+		return -ENODEV;
+
+	if (!klp_have_reliable_stack()) {
+		pr_warn("This architecture doesn't have support for the livepatch consistency model.\n");
+		pr_warn("The livepatch transition may never complete.\n");
+	}
+
+	mutex_lock(&klp_mutex);
+
+	if (!klp_is_patch_compatible(patch)) {
+		pr_err("Livepatch patch (%s) is not compatible with the already installed livepatches.\n",
+			patch->mod->name);
+		mutex_unlock(&klp_mutex);
+		return -EINVAL;
+	}
+
+	if (!try_module_get(patch->mod)) {
+		mutex_unlock(&klp_mutex);
+		return -ENODEV;
+	}
+
+	klp_init_patch_early(patch);
+
+	ret = klp_init_patch(patch);
+	if (ret)
+		goto err;
+
+	ret = __klp_enable_patch(patch);
+	if (ret)
+		goto err;
+
+	mutex_unlock(&klp_mutex);
+
+	return 0;
+
+err:
+	klp_free_patch_start(patch);
+
+	mutex_unlock(&klp_mutex);
+
+	klp_free_patch_finish(patch);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(klp_enable_patch);
+
+/*
+ * This function unpatches objects from the replaced livepatches.
+ *
+ * We could be pretty aggressive here. It is called in the situation where
+ * these structures are no longer accessed from the ftrace handler.
+ * All functions are redirected by the klp_transition_patch. They
+ * use either a new code or they are in the original code because
+ * of the special nop function patches.
+ *
+ * The only exception is when the transition was forced. In this case,
+ * klp_ftrace_handler() might still see the replaced patch on the stack.
+ * Fortunately, it is carefully designed to work with removed functions
+ * thanks to RCU. We only have to keep the patches on the system. Also
+ * this is handled transparently by patch->module_put.
+ */
+void klp_unpatch_replaced_patches(struct klp_patch *new_patch)
+{
+	struct klp_patch *old_patch;
+
+	klp_for_each_patch(old_patch) {
+		if (old_patch == new_patch)
+			return;
+
+		old_patch->enabled = false;
+		klp_unpatch_objects(old_patch);
+	}
+}
+
+/*
+ * This function removes the dynamically allocated 'nop' functions.
+ *
+ * We could be pretty aggressive. NOPs do not change the existing
+ * behavior except for adding unnecessary delay by the ftrace handler.
+ *
+ * It is safe even when the transition was forced. The ftrace handler
+ * will see a valid ops->func_stack entry thanks to RCU.
+ *
+ * We could even free the NOPs structures. They must be the last entry
+ * in ops->func_stack. Therefore unregister_ftrace_function() is called.
+ * It does the same as klp_synchronize_transition() to make sure that
+ * nobody is inside the ftrace handler once the operation finishes.
+ *
+ * IMPORTANT: It must be called right after removing the replaced patches!
+ */
+void klp_discard_nops(struct klp_patch *new_patch)
+{
+	klp_unpatch_objects_dynamic(klp_transition_patch);
+	klp_free_objects_dynamic(klp_transition_patch);
+}
+
+/*
+ * Remove parts of patches that touch a given kernel module. The list of
+ * patches processed might be limited. When limit is NULL, all patches
+ * will be handled.
+ */
+static void klp_cleanup_module_patches_limited(struct module *mod,
+					       struct klp_patch *limit)
+{
+	struct klp_patch *patch;
+	struct klp_object *obj;
+
+	klp_for_each_patch(patch) {
+		if (patch == limit)
+			break;
+
+		klp_for_each_object(patch, obj) {
+			if (!klp_is_module(obj) || strcmp(obj->name, mod->name))
+				continue;
+
+			if (patch != klp_transition_patch)
+				klp_pre_unpatch_callback(obj);
+
+			pr_notice("reverting patch '%s' on unloading module '%s'\n",
+				  patch->mod->name, obj->mod->name);
+			klp_unpatch_object(obj);
+
+			klp_post_unpatch_callback(obj);
+
+			klp_free_object_loaded(obj);
+			break;
+		}
+	}
+}
+
+int klp_module_coming(struct module *mod)
+{
+	int ret;
+	struct klp_patch *patch;
+	struct klp_object *obj;
+
+	if (WARN_ON(mod->state != MODULE_STATE_COMING))
+		return -EINVAL;
+
+	if (!strcmp(mod->name, "vmlinux")) {
+		pr_err("vmlinux.ko: invalid module name\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&klp_mutex);
+	/*
+	 * Each module has to know that klp_module_coming()
+	 * has been called. We never know what module will
+	 * get patched by a new patch.
+	 */
+	mod->klp_alive = true;
+
+	klp_for_each_patch(patch) {
+		klp_for_each_object(patch, obj) {
+			if (!klp_is_module(obj) || strcmp(obj->name, mod->name))
+				continue;
+
+			obj->mod = mod;
+
+			ret = klp_init_object_loaded(patch, obj);
+			if (ret) {
+				pr_warn("failed to initialize patch '%s' for module '%s' (%d)\n",
+					patch->mod->name, obj->mod->name, ret);
+				goto err;
+			}
+
+			pr_notice("applying patch '%s' to loading module '%s'\n",
+				  patch->mod->name, obj->mod->name);
+
+			ret = klp_pre_patch_callback(obj);
+			if (ret) {
+				pr_warn("pre-patch callback failed for object '%s'\n",
+					obj->name);
+				goto err;
+			}
+
+			ret = klp_patch_object(obj);
+			if (ret) {
+				pr_warn("failed to apply patch '%s' to module '%s' (%d)\n",
+					patch->mod->name, obj->mod->name, ret);
+
+				klp_post_unpatch_callback(obj);
+				goto err;
+			}
+
+			if (patch != klp_transition_patch)
+				klp_post_patch_callback(obj);
+
+			break;
+		}
+	}
+
+	mutex_unlock(&klp_mutex);
+
+	return 0;
+
+err:
+	/*
+	 * If a patch is unsuccessfully applied, return
+	 * error to the module loader.
+	 */
+	pr_warn("patch '%s' failed for module '%s', refusing to load module '%s'\n",
+		patch->mod->name, obj->mod->name, obj->mod->name);
+	mod->klp_alive = false;
+	obj->mod = NULL;
+	klp_cleanup_module_patches_limited(mod, patch);
+	mutex_unlock(&klp_mutex);
+
+	return ret;
+}
+
+void klp_module_going(struct module *mod)
+{
+	if (WARN_ON(mod->state != MODULE_STATE_GOING &&
+		    mod->state != MODULE_STATE_COMING))
+		return;
+
+	mutex_lock(&klp_mutex);
+	/*
+	 * Each module has to know that klp_module_going()
+	 * has been called. We never know what module will
+	 * get patched by a new patch.
+	 */
+	mod->klp_alive = false;
+
+	klp_cleanup_module_patches_limited(mod, NULL);
+
+	mutex_unlock(&klp_mutex);
+}
+
+static int __init klp_init(void)
+{
+	klp_root_kobj = kobject_create_and_add("livepatch", kernel_kobj);
+	if (!klp_root_kobj)
+		return -ENOMEM;
+
+	return 0;
+}
+
+module_init(klp_init);
diff --git a/kernel/livepatch/core.h b/kernel/livepatch/core.h
new file mode 100644
index 000000000..38209c736
--- /dev/null
+++ b/kernel/livepatch/core.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LIVEPATCH_CORE_H
+#define _LIVEPATCH_CORE_H
+
+#include <linux/livepatch.h>
+
+extern struct mutex klp_mutex;
+extern struct list_head klp_patches;
+
+#define klp_for_each_patch_safe(patch, tmp_patch)		\
+	list_for_each_entry_safe(patch, tmp_patch, &klp_patches, list)
+
+#define klp_for_each_patch(patch)	\
+	list_for_each_entry(patch, &klp_patches, list)
+
+void klp_free_patch_async(struct klp_patch *patch);
+void klp_free_replaced_patches_async(struct klp_patch *new_patch);
+void klp_unpatch_replaced_patches(struct klp_patch *new_patch);
+void klp_discard_nops(struct klp_patch *new_patch);
+
+static inline bool klp_is_object_loaded(struct klp_object *obj)
+{
+	return !obj->name || obj->mod;
+}
+
+static inline int klp_pre_patch_callback(struct klp_object *obj)
+{
+	int ret = 0;
+
+	if (obj->callbacks.pre_patch)
+		ret = (*obj->callbacks.pre_patch)(obj);
+
+	obj->callbacks.post_unpatch_enabled = !ret;
+
+	return ret;
+}
+
+static inline void klp_post_patch_callback(struct klp_object *obj)
+{
+	if (obj->callbacks.post_patch)
+		(*obj->callbacks.post_patch)(obj);
+}
+
+static inline void klp_pre_unpatch_callback(struct klp_object *obj)
+{
+	if (obj->callbacks.pre_unpatch)
+		(*obj->callbacks.pre_unpatch)(obj);
+}
+
+static inline void klp_post_unpatch_callback(struct klp_object *obj)
+{
+	if (obj->callbacks.post_unpatch_enabled &&
+	    obj->callbacks.post_unpatch)
+		(*obj->callbacks.post_unpatch)(obj);
+
+	obj->callbacks.post_unpatch_enabled = false;
+}
+
+#endif /* _LIVEPATCH_CORE_H */
diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c
new file mode 100644
index 000000000..4c4f5a776
--- /dev/null
+++ b/kernel/livepatch/patch.c
@@ -0,0 +1,289 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * patch.c - livepatch patching functions
+ *
+ * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
+ * Copyright (C) 2014 SUSE
+ * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/livepatch.h>
+#include <linux/list.h>
+#include <linux/ftrace.h>
+#include <linux/rculist.h>
+#include <linux/slab.h>
+#include <linux/bug.h>
+#include <linux/printk.h>
+#include "core.h"
+#include "patch.h"
+#include "transition.h"
+
+static LIST_HEAD(klp_ops);
+
+struct klp_ops *klp_find_ops(void *old_func)
+{
+	struct klp_ops *ops;
+	struct klp_func *func;
+
+	list_for_each_entry(ops, &klp_ops, node) {
+		func = list_first_entry(&ops->func_stack, struct klp_func,
+					stack_node);
+		if (func->old_func == old_func)
+			return ops;
+	}
+
+	return NULL;
+}
+
+static void notrace klp_ftrace_handler(unsigned long ip,
+				       unsigned long parent_ip,
+				       struct ftrace_ops *fops,
+				       struct ftrace_regs *fregs)
+{
+	struct klp_ops *ops;
+	struct klp_func *func;
+	int patch_state;
+	int bit;
+
+	ops = container_of(fops, struct klp_ops, fops);
+
+	/*
+	 * The ftrace_test_recursion_trylock() will disable preemption,
+	 * which is required for the variant of synchronize_rcu() that is
+	 * used to allow patching functions where RCU is not watching.
+	 * See klp_synchronize_transition() for more details.
+	 */
+	bit = ftrace_test_recursion_trylock(ip, parent_ip);
+	if (WARN_ON_ONCE(bit < 0))
+		return;
+
+	func = list_first_or_null_rcu(&ops->func_stack, struct klp_func,
+				      stack_node);
+
+	/*
+	 * func should never be NULL because preemption should be disabled here
+	 * and unregister_ftrace_function() does the equivalent of a
+	 * synchronize_rcu() before the func_stack removal.
+	 */
+	if (WARN_ON_ONCE(!func))
+		goto unlock;
+
+	/*
+	 * In the enable path, enforce the order of the ops->func_stack and
+	 * func->transition reads.  The corresponding write barrier is in
+	 * __klp_enable_patch().
+	 *
+	 * (Note that this barrier technically isn't needed in the disable
+	 * path.  In the rare case where klp_update_patch_state() runs before
+	 * this handler, its TIF_PATCH_PENDING read and this func->transition
+	 * read need to be ordered.  But klp_update_patch_state() already
+	 * enforces that.)
+	 */
+	smp_rmb();
+
+	if (unlikely(func->transition)) {
+
+		/*
+		 * Enforce the order of the func->transition and
+		 * current->patch_state reads.  Otherwise we could read an
+		 * out-of-date task state and pick the wrong function.  The
+		 * corresponding write barrier is in klp_init_transition().
+		 */
+		smp_rmb();
+
+		patch_state = current->patch_state;
+
+		WARN_ON_ONCE(patch_state == KLP_UNDEFINED);
+
+		if (patch_state == KLP_UNPATCHED) {
+			/*
+			 * Use the previously patched version of the function.
+			 * If no previous patches exist, continue with the
+			 * original function.
+			 */
+			func = list_entry_rcu(func->stack_node.next,
+					      struct klp_func, stack_node);
+
+			if (&func->stack_node == &ops->func_stack)
+				goto unlock;
+		}
+	}
+
+	/*
+	 * NOPs are used to replace existing patches with original code.
+	 * Do nothing! Setting pc would cause an infinite loop.
+	 */
+	if (func->nop)
+		goto unlock;
+
+	ftrace_instruction_pointer_set(fregs, (unsigned long)func->new_func);
+
+unlock:
+	ftrace_test_recursion_unlock(bit);
+}
+
+static void klp_unpatch_func(struct klp_func *func)
+{
+	struct klp_ops *ops;
+
+	if (WARN_ON(!func->patched))
+		return;
+	if (WARN_ON(!func->old_func))
+		return;
+
+	ops = klp_find_ops(func->old_func);
+	if (WARN_ON(!ops))
+		return;
+
+	if (list_is_singular(&ops->func_stack)) {
+		unsigned long ftrace_loc;
+
+		ftrace_loc = ftrace_location((unsigned long)func->old_func);
+		if (WARN_ON(!ftrace_loc))
+			return;
+
+		WARN_ON(unregister_ftrace_function(&ops->fops));
+		WARN_ON(ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0));
+
+		list_del_rcu(&func->stack_node);
+		list_del(&ops->node);
+		kfree(ops);
+	} else {
+		list_del_rcu(&func->stack_node);
+	}
+
+	func->patched = false;
+}
+
+static int klp_patch_func(struct klp_func *func)
+{
+	struct klp_ops *ops;
+	int ret;
+
+	if (WARN_ON(!func->old_func))
+		return -EINVAL;
+
+	if (WARN_ON(func->patched))
+		return -EINVAL;
+
+	ops = klp_find_ops(func->old_func);
+	if (!ops) {
+		unsigned long ftrace_loc;
+
+		ftrace_loc = ftrace_location((unsigned long)func->old_func);
+		if (!ftrace_loc) {
+			pr_err("failed to find location for function '%s'\n",
+				func->old_name);
+			return -EINVAL;
+		}
+
+		ops = kzalloc(sizeof(*ops), GFP_KERNEL);
+		if (!ops)
+			return -ENOMEM;
+
+		ops->fops.func = klp_ftrace_handler;
+		ops->fops.flags = FTRACE_OPS_FL_DYNAMIC |
+#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
+				  FTRACE_OPS_FL_SAVE_REGS |
+#endif
+				  FTRACE_OPS_FL_IPMODIFY |
+				  FTRACE_OPS_FL_PERMANENT;
+
+		list_add(&ops->node, &klp_ops);
+
+		INIT_LIST_HEAD(&ops->func_stack);
+		list_add_rcu(&func->stack_node, &ops->func_stack);
+
+		ret = ftrace_set_filter_ip(&ops->fops, ftrace_loc, 0, 0);
+		if (ret) {
+			pr_err("failed to set ftrace filter for function '%s' (%d)\n",
+			       func->old_name, ret);
+			goto err;
+		}
+
+		ret = register_ftrace_function(&ops->fops);
+		if (ret) {
+			pr_err("failed to register ftrace handler for function '%s' (%d)\n",
+			       func->old_name, ret);
+			ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0);
+			goto err;
+		}
+
+
+	} else {
+		list_add_rcu(&func->stack_node, &ops->func_stack);
+	}
+
+	func->patched = true;
+
+	return 0;
+
+err:
+	list_del_rcu(&func->stack_node);
+	list_del(&ops->node);
+	kfree(ops);
+	return ret;
+}
+
+static void __klp_unpatch_object(struct klp_object *obj, bool nops_only)
+{
+	struct klp_func *func;
+
+	klp_for_each_func(obj, func) {
+		if (nops_only && !func->nop)
+			continue;
+
+		if (func->patched)
+			klp_unpatch_func(func);
+	}
+
+	if (obj->dynamic || !nops_only)
+		obj->patched = false;
+}
+
+
+void klp_unpatch_object(struct klp_object *obj)
+{
+	__klp_unpatch_object(obj, false);
+}
+
+int klp_patch_object(struct klp_object *obj)
+{
+	struct klp_func *func;
+	int ret;
+
+	if (WARN_ON(obj->patched))
+		return -EINVAL;
+
+	klp_for_each_func(obj, func) {
+		ret = klp_patch_func(func);
+		if (ret) {
+			klp_unpatch_object(obj);
+			return ret;
+		}
+	}
+	obj->patched = true;
+
+	return 0;
+}
+
+static void __klp_unpatch_objects(struct klp_patch *patch, bool nops_only)
+{
+	struct klp_object *obj;
+
+	klp_for_each_object(patch, obj)
+		if (obj->patched)
+			__klp_unpatch_object(obj, nops_only);
+}
+
+void klp_unpatch_objects(struct klp_patch *patch)
+{
+	__klp_unpatch_objects(patch, false);
+}
+
+void klp_unpatch_objects_dynamic(struct klp_patch *patch)
+{
+	__klp_unpatch_objects(patch, true);
+}
diff --git a/kernel/livepatch/patch.h b/kernel/livepatch/patch.h
new file mode 100644
index 000000000..d5f2fbe37
--- /dev/null
+++ b/kernel/livepatch/patch.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LIVEPATCH_PATCH_H
+#define _LIVEPATCH_PATCH_H
+
+#include <linux/livepatch.h>
+#include <linux/list.h>
+#include <linux/ftrace.h>
+
+/**
+ * struct klp_ops - structure for tracking registered ftrace ops structs
+ *
+ * A single ftrace_ops is shared between all enabled replacement functions
+ * (klp_func structs) which have the same old_func.  This allows the switch
+ * between function versions to happen instantaneously by updating the klp_ops
+ * struct's func_stack list.  The winner is the klp_func at the top of the
+ * func_stack (front of the list).
+ *
+ * @node:	node for the global klp_ops list
+ * @func_stack:	list head for the stack of klp_func's (active func is on top)
+ * @fops:	registered ftrace ops struct
+ */
+struct klp_ops {
+	struct list_head node;
+	struct list_head func_stack;
+	struct ftrace_ops fops;
+};
+
+struct klp_ops *klp_find_ops(void *old_func);
+
+int klp_patch_object(struct klp_object *obj);
+void klp_unpatch_object(struct klp_object *obj);
+void klp_unpatch_objects(struct klp_patch *patch);
+void klp_unpatch_objects_dynamic(struct klp_patch *patch);
+
+#endif /* _LIVEPATCH_PATCH_H */
diff --git a/kernel/livepatch/shadow.c b/kernel/livepatch/shadow.c
new file mode 100644
index 000000000..c2e724d97
--- /dev/null
+++ b/kernel/livepatch/shadow.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * shadow.c - Shadow Variables
+ *
+ * Copyright (C) 2014 Josh Poimboeuf <jpoimboe@redhat.com>
+ * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
+ * Copyright (C) 2017 Joe Lawrence <joe.lawrence@redhat.com>
+ */
+
+/**
+ * DOC: Shadow variable API concurrency notes:
+ *
+ * The shadow variable API provides a simple relationship between an
+ * <obj, id> pair and a pointer value.  It is the responsibility of the
+ * caller to provide any mutual exclusion required of the shadow data.
+ *
+ * Once a shadow variable is attached to its parent object via the
+ * klp_shadow_*alloc() API calls, it is considered live: any subsequent
+ * call to klp_shadow_get() may then return the shadow variable's data
+ * pointer.  Callers of klp_shadow_*alloc() should prepare shadow data
+ * accordingly.
+ *
+ * The klp_shadow_*alloc() API calls may allocate memory for new shadow
+ * variable structures.  Their implementation does not call kmalloc
+ * inside any spinlocks, but API callers should pass GFP flags according
+ * to their specific needs.
+ *
+ * The klp_shadow_hash is an RCU-enabled hashtable and is safe against
+ * concurrent klp_shadow_free() and klp_shadow_get() operations.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/hashtable.h>
+#include <linux/slab.h>
+#include <linux/livepatch.h>
+
+static DEFINE_HASHTABLE(klp_shadow_hash, 12);
+
+/*
+ * klp_shadow_lock provides exclusive access to the klp_shadow_hash and
+ * the shadow variables it references.
+ */
+static DEFINE_SPINLOCK(klp_shadow_lock);
+
+/**
+ * struct klp_shadow - shadow variable structure
+ * @node:	klp_shadow_hash hash table node
+ * @rcu_head:	RCU is used to safely free this structure
+ * @obj:	pointer to parent object
+ * @id:		data identifier
+ * @data:	data area
+ */
+struct klp_shadow {
+	struct hlist_node node;
+	struct rcu_head rcu_head;
+	void *obj;
+	unsigned long id;
+	char data[];
+};
+
+/**
+ * klp_shadow_match() - verify a shadow variable matches given <obj, id>
+ * @shadow:	shadow variable to match
+ * @obj:	pointer to parent object
+ * @id:		data identifier
+ *
+ * Return: true if the shadow variable matches.
+ */
+static inline bool klp_shadow_match(struct klp_shadow *shadow, void *obj,
+				unsigned long id)
+{
+	return shadow->obj == obj && shadow->id == id;
+}
+
+/**
+ * klp_shadow_get() - retrieve a shadow variable data pointer
+ * @obj:	pointer to parent object
+ * @id:		data identifier
+ *
+ * Return: the shadow variable data element, NULL on failure.
+ */
+void *klp_shadow_get(void *obj, unsigned long id)
+{
+	struct klp_shadow *shadow;
+
+	rcu_read_lock();
+
+	hash_for_each_possible_rcu(klp_shadow_hash, shadow, node,
+				   (unsigned long)obj) {
+
+		if (klp_shadow_match(shadow, obj, id)) {
+			rcu_read_unlock();
+			return shadow->data;
+		}
+	}
+
+	rcu_read_unlock();
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(klp_shadow_get);
+
+static void *__klp_shadow_get_or_alloc(void *obj, unsigned long id,
+				       size_t size, gfp_t gfp_flags,
+				       klp_shadow_ctor_t ctor, void *ctor_data,
+				       bool warn_on_exist)
+{
+	struct klp_shadow *new_shadow;
+	void *shadow_data;
+	unsigned long flags;
+
+	/* Check if the shadow variable already exists */
+	shadow_data = klp_shadow_get(obj, id);
+	if (shadow_data)
+		goto exists;
+
+	/*
+	 * Allocate a new shadow variable.  Fill it with zeroes by default.
+	 * More complex setting can be done by @ctor function.  But it is
+	 * called only when the buffer is really used (under klp_shadow_lock).
+	 */
+	new_shadow = kzalloc(size + sizeof(*new_shadow), gfp_flags);
+	if (!new_shadow)
+		return NULL;
+
+	/* Look for <obj, id> again under the lock */
+	spin_lock_irqsave(&klp_shadow_lock, flags);
+	shadow_data = klp_shadow_get(obj, id);
+	if (unlikely(shadow_data)) {
+		/*
+		 * Shadow variable was found, throw away speculative
+		 * allocation.
+		 */
+		spin_unlock_irqrestore(&klp_shadow_lock, flags);
+		kfree(new_shadow);
+		goto exists;
+	}
+
+	new_shadow->obj = obj;
+	new_shadow->id = id;
+
+	if (ctor) {
+		int err;
+
+		err = ctor(obj, new_shadow->data, ctor_data);
+		if (err) {
+			spin_unlock_irqrestore(&klp_shadow_lock, flags);
+			kfree(new_shadow);
+			pr_err("Failed to construct shadow variable <%p, %lx> (%d)\n",
+			       obj, id, err);
+			return NULL;
+		}
+	}
+
+	/* No <obj, id> found, so attach the newly allocated one */
+	hash_add_rcu(klp_shadow_hash, &new_shadow->node,
+		     (unsigned long)new_shadow->obj);
+	spin_unlock_irqrestore(&klp_shadow_lock, flags);
+
+	return new_shadow->data;
+
+exists:
+	if (warn_on_exist) {
+		WARN(1, "Duplicate shadow variable <%p, %lx>\n", obj, id);
+		return NULL;
+	}
+
+	return shadow_data;
+}
+
+/**
+ * klp_shadow_alloc() - allocate and add a new shadow variable
+ * @obj:	pointer to parent object
+ * @id:		data identifier
+ * @size:	size of attached data
+ * @gfp_flags:	GFP mask for allocation
+ * @ctor:	custom constructor to initialize the shadow data (optional)
+ * @ctor_data:	pointer to any data needed by @ctor (optional)
+ *
+ * Allocates @size bytes for new shadow variable data using @gfp_flags.
+ * The data are zeroed by default.  They are further initialized by @ctor
+ * function if it is not NULL.  The new shadow variable is then added
+ * to the global hashtable.
+ *
+ * If an existing <obj, id> shadow variable can be found, this routine will
+ * issue a WARN, exit early and return NULL.
+ *
+ * This function guarantees that the constructor function is called only when
+ * the variable did not exist before.  The cost is that @ctor is called
+ * in atomic context under a spin lock.
+ *
+ * Return: the shadow variable data element, NULL on duplicate or
+ * failure.
+ */
+void *klp_shadow_alloc(void *obj, unsigned long id,
+		       size_t size, gfp_t gfp_flags,
+		       klp_shadow_ctor_t ctor, void *ctor_data)
+{
+	return __klp_shadow_get_or_alloc(obj, id, size, gfp_flags,
+					 ctor, ctor_data, true);
+}
+EXPORT_SYMBOL_GPL(klp_shadow_alloc);
+
+/**
+ * klp_shadow_get_or_alloc() - get existing or allocate a new shadow variable
+ * @obj:	pointer to parent object
+ * @id:		data identifier
+ * @size:	size of attached data
+ * @gfp_flags:	GFP mask for allocation
+ * @ctor:	custom constructor to initialize the shadow data (optional)
+ * @ctor_data:	pointer to any data needed by @ctor (optional)
+ *
+ * Returns a pointer to existing shadow data if an <obj, id> shadow
+ * variable is already present.  Otherwise, it creates a new shadow
+ * variable like klp_shadow_alloc().
+ *
+ * This function guarantees that only one shadow variable exists with the given
+ * @id for the given @obj.  It also guarantees that the constructor function
+ * will be called only when the variable did not exist before.  The cost is
+ * that @ctor is called in atomic context under a spin lock.
+ *
+ * Return: the shadow variable data element, NULL on failure.
+ */
+void *klp_shadow_get_or_alloc(void *obj, unsigned long id,
+			      size_t size, gfp_t gfp_flags,
+			      klp_shadow_ctor_t ctor, void *ctor_data)
+{
+	return __klp_shadow_get_or_alloc(obj, id, size, gfp_flags,
+					 ctor, ctor_data, false);
+}
+EXPORT_SYMBOL_GPL(klp_shadow_get_or_alloc);
+
+static void klp_shadow_free_struct(struct klp_shadow *shadow,
+				   klp_shadow_dtor_t dtor)
+{
+	hash_del_rcu(&shadow->node);
+	if (dtor)
+		dtor(shadow->obj, shadow->data);
+	kfree_rcu(shadow, rcu_head);
+}
+
+/**
+ * klp_shadow_free() - detach and free a <obj, id> shadow variable
+ * @obj:	pointer to parent object
+ * @id:		data identifier
+ * @dtor:	custom callback that can be used to unregister the variable
+ *		and/or free data that the shadow variable points to (optional)
+ *
+ * This function releases the memory for this <obj, id> shadow variable
+ * instance, callers should stop referencing it accordingly.
+ */
+void klp_shadow_free(void *obj, unsigned long id, klp_shadow_dtor_t dtor)
+{
+	struct klp_shadow *shadow;
+	unsigned long flags;
+
+	spin_lock_irqsave(&klp_shadow_lock, flags);
+
+	/* Delete <obj, id> from hash */
+	hash_for_each_possible(klp_shadow_hash, shadow, node,
+			       (unsigned long)obj) {
+
+		if (klp_shadow_match(shadow, obj, id)) {
+			klp_shadow_free_struct(shadow, dtor);
+			break;
+		}
+	}
+
+	spin_unlock_irqrestore(&klp_shadow_lock, flags);
+}
+EXPORT_SYMBOL_GPL(klp_shadow_free);
+
+/**
+ * klp_shadow_free_all() - detach and free all <_, id> shadow variables
+ * @id:		data identifier
+ * @dtor:	custom callback that can be used to unregister the variable
+ *		and/or free data that the shadow variable points to (optional)
+ *
+ * This function releases the memory for all <_, id> shadow variable
+ * instances, callers should stop referencing them accordingly.
+ */
+void klp_shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor)
+{
+	struct klp_shadow *shadow;
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&klp_shadow_lock, flags);
+
+	/* Delete all <_, id> from hash */
+	hash_for_each(klp_shadow_hash, i, shadow, node) {
+		if (klp_shadow_match(shadow, shadow->obj, id))
+			klp_shadow_free_struct(shadow, dtor);
+	}
+
+	spin_unlock_irqrestore(&klp_shadow_lock, flags);
+}
+EXPORT_SYMBOL_GPL(klp_shadow_free_all);
diff --git a/kernel/livepatch/state.c b/kernel/livepatch/state.c
new file mode 100644
index 000000000..2565d039a
--- /dev/null
+++ b/kernel/livepatch/state.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * system_state.c - State of the system modified by livepatches
+ *
+ * Copyright (C) 2019 SUSE
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/livepatch.h>
+#include "core.h"
+#include "state.h"
+#include "transition.h"
+
+#define klp_for_each_state(patch, state)		\
+	for (state = patch->states; state && state->id; state++)
+
+/**
+ * klp_get_state() - get information about system state modified by
+ *	the given patch
+ * @patch:	livepatch that modifies the given system state
+ * @id:		custom identifier of the modified system state
+ *
+ * Checks whether the given patch modifies the given system state.
+ *
+ * The function can be called either from pre/post (un)patch
+ * callbacks or from the kernel code added by the livepatch.
+ *
+ * Return: pointer to struct klp_state when found, otherwise NULL.
+ */
+struct klp_state *klp_get_state(struct klp_patch *patch, unsigned long id)
+{
+	struct klp_state *state;
+
+	klp_for_each_state(patch, state) {
+		if (state->id == id)
+			return state;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(klp_get_state);
+
+/**
+ * klp_get_prev_state() - get information about system state modified by
+ *	the already installed livepatches
+ * @id:		custom identifier of the modified system state
+ *
+ * Checks whether already installed livepatches modify the given
+ * system state.
+ *
+ * The same system state can be modified by more non-cumulative
+ * livepatches. It is expected that the latest livepatch has
+ * the most up-to-date information.
+ *
+ * The function can be called only during transition when a new
+ * livepatch is being enabled or when such a transition is reverted.
+ * It is typically called only from pre/post (un)patch
+ * callbacks.
+ *
+ * Return: pointer to the latest struct klp_state from already
+ *	installed livepatches, NULL when not found.
+ */
+struct klp_state *klp_get_prev_state(unsigned long id)
+{
+	struct klp_patch *patch;
+	struct klp_state *state, *last_state = NULL;
+
+	if (WARN_ON_ONCE(!klp_transition_patch))
+		return NULL;
+
+	klp_for_each_patch(patch) {
+		if (patch == klp_transition_patch)
+			goto out;
+
+		state = klp_get_state(patch, id);
+		if (state)
+			last_state = state;
+	}
+
+out:
+	return last_state;
+}
+EXPORT_SYMBOL_GPL(klp_get_prev_state);
+
+/* Check if the patch is able to deal with the existing system state. */
+static bool klp_is_state_compatible(struct klp_patch *patch,
+				    struct klp_state *old_state)
+{
+	struct klp_state *state;
+
+	state = klp_get_state(patch, old_state->id);
+
+	/* A cumulative livepatch must handle all already modified states. */
+	if (!state)
+		return !patch->replace;
+
+	return state->version >= old_state->version;
+}
+
+/*
+ * Check that the new livepatch will not break the existing system states.
+ * Cumulative patches must handle all already modified states.
+ * Non-cumulative patches can touch already modified states.
+ */
+bool klp_is_patch_compatible(struct klp_patch *patch)
+{
+	struct klp_patch *old_patch;
+	struct klp_state *old_state;
+
+	klp_for_each_patch(old_patch) {
+		klp_for_each_state(old_patch, old_state) {
+			if (!klp_is_state_compatible(patch, old_state))
+				return false;
+		}
+	}
+
+	return true;
+}
diff --git a/kernel/livepatch/state.h b/kernel/livepatch/state.h
new file mode 100644
index 000000000..49d9c16e8
--- /dev/null
+++ b/kernel/livepatch/state.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LIVEPATCH_STATE_H
+#define _LIVEPATCH_STATE_H
+
+#include <linux/livepatch.h>
+
+bool klp_is_patch_compatible(struct klp_patch *patch);
+
+#endif /* _LIVEPATCH_STATE_H */
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
new file mode 100644
index 000000000..30187b1d8
--- /dev/null
+++ b/kernel/livepatch/transition.c
@@ -0,0 +1,666 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * transition.c - Kernel Live Patching transition functions
+ *
+ * Copyright (C) 2015-2016 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/cpu.h>
+#include <linux/stacktrace.h>
+#include "core.h"
+#include "patch.h"
+#include "transition.h"
+
+#define MAX_STACK_ENTRIES  100
+#define STACK_ERR_BUF_SIZE 128
+
+#define SIGNALS_TIMEOUT 15
+
+struct klp_patch *klp_transition_patch;
+
+static int klp_target_state = KLP_UNDEFINED;
+
+static unsigned int klp_signals_cnt;
+
+/*
+ * This work can be performed periodically to finish patching or unpatching any
+ * "straggler" tasks which failed to transition in the first attempt.
+ */
+static void klp_transition_work_fn(struct work_struct *work)
+{
+	mutex_lock(&klp_mutex);
+
+	if (klp_transition_patch)
+		klp_try_complete_transition();
+
+	mutex_unlock(&klp_mutex);
+}
+static DECLARE_DELAYED_WORK(klp_transition_work, klp_transition_work_fn);
+
+/*
+ * This function is just a stub to implement a hard force
+ * of synchronize_rcu(). This requires synchronizing
+ * tasks even in userspace and idle.
+ */
+static void klp_sync(struct work_struct *work)
+{
+}
+
+/*
+ * We allow to patch also functions where RCU is not watching,
+ * e.g. before user_exit(). We can not rely on the RCU infrastructure
+ * to do the synchronization. Instead hard force the sched synchronization.
+ *
+ * This approach allows to use RCU functions for manipulating func_stack
+ * safely.
+ */
+static void klp_synchronize_transition(void)
+{
+	schedule_on_each_cpu(klp_sync);
+}
+
+/*
+ * The transition to the target patch state is complete.  Clean up the data
+ * structures.
+ */
+static void klp_complete_transition(void)
+{
+	struct klp_object *obj;
+	struct klp_func *func;
+	struct task_struct *g, *task;
+	unsigned int cpu;
+
+	pr_debug("'%s': completing %s transition\n",
+		 klp_transition_patch->mod->name,
+		 klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
+
+	if (klp_transition_patch->replace && klp_target_state == KLP_PATCHED) {
+		klp_unpatch_replaced_patches(klp_transition_patch);
+		klp_discard_nops(klp_transition_patch);
+	}
+
+	if (klp_target_state == KLP_UNPATCHED) {
+		/*
+		 * All tasks have transitioned to KLP_UNPATCHED so we can now
+		 * remove the new functions from the func_stack.
+		 */
+		klp_unpatch_objects(klp_transition_patch);
+
+		/*
+		 * Make sure klp_ftrace_handler() can no longer see functions
+		 * from this patch on the ops->func_stack.  Otherwise, after
+		 * func->transition gets cleared, the handler may choose a
+		 * removed function.
+		 */
+		klp_synchronize_transition();
+	}
+
+	klp_for_each_object(klp_transition_patch, obj)
+		klp_for_each_func(obj, func)
+			func->transition = false;
+
+	/* Prevent klp_ftrace_handler() from seeing KLP_UNDEFINED state */
+	if (klp_target_state == KLP_PATCHED)
+		klp_synchronize_transition();
+
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, task) {
+		WARN_ON_ONCE(test_tsk_thread_flag(task, TIF_PATCH_PENDING));
+		task->patch_state = KLP_UNDEFINED;
+	}
+	read_unlock(&tasklist_lock);
+
+	for_each_possible_cpu(cpu) {
+		task = idle_task(cpu);
+		WARN_ON_ONCE(test_tsk_thread_flag(task, TIF_PATCH_PENDING));
+		task->patch_state = KLP_UNDEFINED;
+	}
+
+	klp_for_each_object(klp_transition_patch, obj) {
+		if (!klp_is_object_loaded(obj))
+			continue;
+		if (klp_target_state == KLP_PATCHED)
+			klp_post_patch_callback(obj);
+		else if (klp_target_state == KLP_UNPATCHED)
+			klp_post_unpatch_callback(obj);
+	}
+
+	pr_notice("'%s': %s complete\n", klp_transition_patch->mod->name,
+		  klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
+
+	klp_target_state = KLP_UNDEFINED;
+	klp_transition_patch = NULL;
+}
+
+/*
+ * This is called in the error path, to cancel a transition before it has
+ * started, i.e. klp_init_transition() has been called but
+ * klp_start_transition() hasn't.  If the transition *has* been started,
+ * klp_reverse_transition() should be used instead.
+ */
+void klp_cancel_transition(void)
+{
+	if (WARN_ON_ONCE(klp_target_state != KLP_PATCHED))
+		return;
+
+	pr_debug("'%s': canceling patching transition, going to unpatch\n",
+		 klp_transition_patch->mod->name);
+
+	klp_target_state = KLP_UNPATCHED;
+	klp_complete_transition();
+}
+
+/*
+ * Switch the patched state of the task to the set of functions in the target
+ * patch state.
+ *
+ * NOTE: If task is not 'current', the caller must ensure the task is inactive.
+ * Otherwise klp_ftrace_handler() might read the wrong 'patch_state' value.
+ */
+void klp_update_patch_state(struct task_struct *task)
+{
+	/*
+	 * A variant of synchronize_rcu() is used to allow patching functions
+	 * where RCU is not watching, see klp_synchronize_transition().
+	 */
+	preempt_disable_notrace();
+
+	/*
+	 * This test_and_clear_tsk_thread_flag() call also serves as a read
+	 * barrier (smp_rmb) for two cases:
+	 *
+	 * 1) Enforce the order of the TIF_PATCH_PENDING read and the
+	 *    klp_target_state read.  The corresponding write barrier is in
+	 *    klp_init_transition().
+	 *
+	 * 2) Enforce the order of the TIF_PATCH_PENDING read and a future read
+	 *    of func->transition, if klp_ftrace_handler() is called later on
+	 *    the same CPU.  See __klp_disable_patch().
+	 */
+	if (test_and_clear_tsk_thread_flag(task, TIF_PATCH_PENDING))
+		task->patch_state = READ_ONCE(klp_target_state);
+
+	preempt_enable_notrace();
+}
+
+/*
+ * Determine whether the given stack trace includes any references to a
+ * to-be-patched or to-be-unpatched function.
+ */
+static int klp_check_stack_func(struct klp_func *func, unsigned long *entries,
+				unsigned int nr_entries)
+{
+	unsigned long func_addr, func_size, address;
+	struct klp_ops *ops;
+	int i;
+
+	for (i = 0; i < nr_entries; i++) {
+		address = entries[i];
+
+		if (klp_target_state == KLP_UNPATCHED) {
+			 /*
+			  * Check for the to-be-unpatched function
+			  * (the func itself).
+			  */
+			func_addr = (unsigned long)func->new_func;
+			func_size = func->new_size;
+		} else {
+			/*
+			 * Check for the to-be-patched function
+			 * (the previous func).
+			 */
+			ops = klp_find_ops(func->old_func);
+
+			if (list_is_singular(&ops->func_stack)) {
+				/* original function */
+				func_addr = (unsigned long)func->old_func;
+				func_size = func->old_size;
+			} else {
+				/* previously patched function */
+				struct klp_func *prev;
+
+				prev = list_next_entry(func, stack_node);
+				func_addr = (unsigned long)prev->new_func;
+				func_size = prev->new_size;
+			}
+		}
+
+		if (address >= func_addr && address < func_addr + func_size)
+			return -EAGAIN;
+	}
+
+	return 0;
+}
+
+/*
+ * Determine whether it's safe to transition the task to the target patch state
+ * by looking for any to-be-patched or to-be-unpatched functions on its stack.
+ */
+static int klp_check_stack(struct task_struct *task, const char **oldname)
+{
+	static unsigned long entries[MAX_STACK_ENTRIES];
+	struct klp_object *obj;
+	struct klp_func *func;
+	int ret, nr_entries;
+
+	ret = stack_trace_save_tsk_reliable(task, entries, ARRAY_SIZE(entries));
+	if (ret < 0)
+		return -EINVAL;
+	nr_entries = ret;
+
+	klp_for_each_object(klp_transition_patch, obj) {
+		if (!obj->patched)
+			continue;
+		klp_for_each_func(obj, func) {
+			ret = klp_check_stack_func(func, entries, nr_entries);
+			if (ret) {
+				*oldname = func->old_name;
+				return -EADDRINUSE;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int klp_check_and_switch_task(struct task_struct *task, void *arg)
+{
+	int ret;
+
+	if (task_curr(task) && task != current)
+		return -EBUSY;
+
+	ret = klp_check_stack(task, arg);
+	if (ret)
+		return ret;
+
+	clear_tsk_thread_flag(task, TIF_PATCH_PENDING);
+	task->patch_state = klp_target_state;
+	return 0;
+}
+
+/*
+ * Try to safely switch a task to the target patch state.  If it's currently
+ * running, or it's sleeping on a to-be-patched or to-be-unpatched function, or
+ * if the stack is unreliable, return false.
+ */
+static bool klp_try_switch_task(struct task_struct *task)
+{
+	const char *old_name;
+	int ret;
+
+	/* check if this task has already switched over */
+	if (task->patch_state == klp_target_state)
+		return true;
+
+	/*
+	 * For arches which don't have reliable stack traces, we have to rely
+	 * on other methods (e.g., switching tasks at kernel exit).
+	 */
+	if (!klp_have_reliable_stack())
+		return false;
+
+	/*
+	 * Now try to check the stack for any to-be-patched or to-be-unpatched
+	 * functions.  If all goes well, switch the task to the target patch
+	 * state.
+	 */
+	ret = task_call_func(task, klp_check_and_switch_task, &old_name);
+	switch (ret) {
+	case 0:		/* success */
+		break;
+
+	case -EBUSY:	/* klp_check_and_switch_task() */
+		pr_debug("%s: %s:%d is running\n",
+			 __func__, task->comm, task->pid);
+		break;
+	case -EINVAL:	/* klp_check_and_switch_task() */
+		pr_debug("%s: %s:%d has an unreliable stack\n",
+			 __func__, task->comm, task->pid);
+		break;
+	case -EADDRINUSE: /* klp_check_and_switch_task() */
+		pr_debug("%s: %s:%d is sleeping on function %s\n",
+			 __func__, task->comm, task->pid, old_name);
+		break;
+
+	default:
+		pr_debug("%s: Unknown error code (%d) when trying to switch %s:%d\n",
+			 __func__, ret, task->comm, task->pid);
+		break;
+	}
+
+	return !ret;
+}
+
+/*
+ * Sends a fake signal to all non-kthread tasks with TIF_PATCH_PENDING set.
+ * Kthreads with TIF_PATCH_PENDING set are woken up.
+ */
+static void klp_send_signals(void)
+{
+	struct task_struct *g, *task;
+
+	if (klp_signals_cnt == SIGNALS_TIMEOUT)
+		pr_notice("signaling remaining tasks\n");
+
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, task) {
+		if (!klp_patch_pending(task))
+			continue;
+
+		/*
+		 * There is a small race here. We could see TIF_PATCH_PENDING
+		 * set and decide to wake up a kthread or send a fake signal.
+		 * Meanwhile the task could migrate itself and the action
+		 * would be meaningless. It is not serious though.
+		 */
+		if (task->flags & PF_KTHREAD) {
+			/*
+			 * Wake up a kthread which sleeps interruptedly and
+			 * still has not been migrated.
+			 */
+			wake_up_state(task, TASK_INTERRUPTIBLE);
+		} else {
+			/*
+			 * Send fake signal to all non-kthread tasks which are
+			 * still not migrated.
+			 */
+			set_notify_signal(task);
+		}
+	}
+	read_unlock(&tasklist_lock);
+}
+
+/*
+ * Try to switch all remaining tasks to the target patch state by walking the
+ * stacks of sleeping tasks and looking for any to-be-patched or
+ * to-be-unpatched functions.  If such functions are found, the task can't be
+ * switched yet.
+ *
+ * If any tasks are still stuck in the initial patch state, schedule a retry.
+ */
+void klp_try_complete_transition(void)
+{
+	unsigned int cpu;
+	struct task_struct *g, *task;
+	struct klp_patch *patch;
+	bool complete = true;
+
+	WARN_ON_ONCE(klp_target_state == KLP_UNDEFINED);
+
+	/*
+	 * Try to switch the tasks to the target patch state by walking their
+	 * stacks and looking for any to-be-patched or to-be-unpatched
+	 * functions.  If such functions are found on a stack, or if the stack
+	 * is deemed unreliable, the task can't be switched yet.
+	 *
+	 * Usually this will transition most (or all) of the tasks on a system
+	 * unless the patch includes changes to a very common function.
+	 */
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, task)
+		if (!klp_try_switch_task(task))
+			complete = false;
+	read_unlock(&tasklist_lock);
+
+	/*
+	 * Ditto for the idle "swapper" tasks.
+	 */
+	cpus_read_lock();
+	for_each_possible_cpu(cpu) {
+		task = idle_task(cpu);
+		if (cpu_online(cpu)) {
+			if (!klp_try_switch_task(task)) {
+				complete = false;
+				/* Make idle task go through the main loop. */
+				wake_up_if_idle(cpu);
+			}
+		} else if (task->patch_state != klp_target_state) {
+			/* offline idle tasks can be switched immediately */
+			clear_tsk_thread_flag(task, TIF_PATCH_PENDING);
+			task->patch_state = klp_target_state;
+		}
+	}
+	cpus_read_unlock();
+
+	if (!complete) {
+		if (klp_signals_cnt && !(klp_signals_cnt % SIGNALS_TIMEOUT))
+			klp_send_signals();
+		klp_signals_cnt++;
+
+		/*
+		 * Some tasks weren't able to be switched over.  Try again
+		 * later and/or wait for other methods like kernel exit
+		 * switching.
+		 */
+		schedule_delayed_work(&klp_transition_work,
+				      round_jiffies_relative(HZ));
+		return;
+	}
+
+	/* we're done, now cleanup the data structures */
+	patch = klp_transition_patch;
+	klp_complete_transition();
+
+	/*
+	 * It would make more sense to free the unused patches in
+	 * klp_complete_transition() but it is called also
+	 * from klp_cancel_transition().
+	 */
+	if (!patch->enabled)
+		klp_free_patch_async(patch);
+	else if (patch->replace)
+		klp_free_replaced_patches_async(patch);
+}
+
+/*
+ * Start the transition to the specified target patch state so tasks can begin
+ * switching to it.
+ */
+void klp_start_transition(void)
+{
+	struct task_struct *g, *task;
+	unsigned int cpu;
+
+	WARN_ON_ONCE(klp_target_state == KLP_UNDEFINED);
+
+	pr_notice("'%s': starting %s transition\n",
+		  klp_transition_patch->mod->name,
+		  klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
+
+	/*
+	 * Mark all normal tasks as needing a patch state update.  They'll
+	 * switch either in klp_try_complete_transition() or as they exit the
+	 * kernel.
+	 */
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, task)
+		if (task->patch_state != klp_target_state)
+			set_tsk_thread_flag(task, TIF_PATCH_PENDING);
+	read_unlock(&tasklist_lock);
+
+	/*
+	 * Mark all idle tasks as needing a patch state update.  They'll switch
+	 * either in klp_try_complete_transition() or at the idle loop switch
+	 * point.
+	 */
+	for_each_possible_cpu(cpu) {
+		task = idle_task(cpu);
+		if (task->patch_state != klp_target_state)
+			set_tsk_thread_flag(task, TIF_PATCH_PENDING);
+	}
+
+	klp_signals_cnt = 0;
+}
+
+/*
+ * Initialize the global target patch state and all tasks to the initial patch
+ * state, and initialize all function transition states to true in preparation
+ * for patching or unpatching.
+ */
+void klp_init_transition(struct klp_patch *patch, int state)
+{
+	struct task_struct *g, *task;
+	unsigned int cpu;
+	struct klp_object *obj;
+	struct klp_func *func;
+	int initial_state = !state;
+
+	WARN_ON_ONCE(klp_target_state != KLP_UNDEFINED);
+
+	klp_transition_patch = patch;
+
+	/*
+	 * Set the global target patch state which tasks will switch to.  This
+	 * has no effect until the TIF_PATCH_PENDING flags get set later.
+	 */
+	klp_target_state = state;
+
+	pr_debug("'%s': initializing %s transition\n", patch->mod->name,
+		 klp_target_state == KLP_PATCHED ? "patching" : "unpatching");
+
+	/*
+	 * Initialize all tasks to the initial patch state to prepare them for
+	 * switching to the target state.
+	 */
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, task) {
+		WARN_ON_ONCE(task->patch_state != KLP_UNDEFINED);
+		task->patch_state = initial_state;
+	}
+	read_unlock(&tasklist_lock);
+
+	/*
+	 * Ditto for the idle "swapper" tasks.
+	 */
+	for_each_possible_cpu(cpu) {
+		task = idle_task(cpu);
+		WARN_ON_ONCE(task->patch_state != KLP_UNDEFINED);
+		task->patch_state = initial_state;
+	}
+
+	/*
+	 * Enforce the order of the task->patch_state initializations and the
+	 * func->transition updates to ensure that klp_ftrace_handler() doesn't
+	 * see a func in transition with a task->patch_state of KLP_UNDEFINED.
+	 *
+	 * Also enforce the order of the klp_target_state write and future
+	 * TIF_PATCH_PENDING writes to ensure klp_update_patch_state() doesn't
+	 * set a task->patch_state to KLP_UNDEFINED.
+	 */
+	smp_wmb();
+
+	/*
+	 * Set the func transition states so klp_ftrace_handler() will know to
+	 * switch to the transition logic.
+	 *
+	 * When patching, the funcs aren't yet in the func_stack and will be
+	 * made visible to the ftrace handler shortly by the calls to
+	 * klp_patch_object().
+	 *
+	 * When unpatching, the funcs are already in the func_stack and so are
+	 * already visible to the ftrace handler.
+	 */
+	klp_for_each_object(patch, obj)
+		klp_for_each_func(obj, func)
+			func->transition = true;
+}
+
+/*
+ * This function can be called in the middle of an existing transition to
+ * reverse the direction of the target patch state.  This can be done to
+ * effectively cancel an existing enable or disable operation if there are any
+ * tasks which are stuck in the initial patch state.
+ */
+void klp_reverse_transition(void)
+{
+	unsigned int cpu;
+	struct task_struct *g, *task;
+
+	pr_debug("'%s': reversing transition from %s\n",
+		 klp_transition_patch->mod->name,
+		 klp_target_state == KLP_PATCHED ? "patching to unpatching" :
+						   "unpatching to patching");
+
+	klp_transition_patch->enabled = !klp_transition_patch->enabled;
+
+	klp_target_state = !klp_target_state;
+
+	/*
+	 * Clear all TIF_PATCH_PENDING flags to prevent races caused by
+	 * klp_update_patch_state() running in parallel with
+	 * klp_start_transition().
+	 */
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, task)
+		clear_tsk_thread_flag(task, TIF_PATCH_PENDING);
+	read_unlock(&tasklist_lock);
+
+	for_each_possible_cpu(cpu)
+		clear_tsk_thread_flag(idle_task(cpu), TIF_PATCH_PENDING);
+
+	/* Let any remaining calls to klp_update_patch_state() complete */
+	klp_synchronize_transition();
+
+	klp_start_transition();
+}
+
+/* Called from copy_process() during fork */
+void klp_copy_process(struct task_struct *child)
+{
+
+	/*
+	 * The parent process may have gone through a KLP transition since
+	 * the thread flag was copied in setup_thread_stack earlier. Bring
+	 * the task flag up to date with the parent here.
+	 *
+	 * The operation is serialized against all klp_*_transition()
+	 * operations by the tasklist_lock. The only exception is
+	 * klp_update_patch_state(current), but we cannot race with
+	 * that because we are current.
+	 */
+	if (test_tsk_thread_flag(current, TIF_PATCH_PENDING))
+		set_tsk_thread_flag(child, TIF_PATCH_PENDING);
+	else
+		clear_tsk_thread_flag(child, TIF_PATCH_PENDING);
+
+	child->patch_state = current->patch_state;
+}
+
+/*
+ * Drop TIF_PATCH_PENDING of all tasks on admin's request. This forces an
+ * existing transition to finish.
+ *
+ * NOTE: klp_update_patch_state(task) requires the task to be inactive or
+ * 'current'. This is not the case here and the consistency model could be
+ * broken. Administrator, who is the only one to execute the
+ * klp_force_transitions(), has to be aware of this.
+ */
+void klp_force_transition(void)
+{
+	struct klp_patch *patch;
+	struct task_struct *g, *task;
+	unsigned int cpu;
+
+	pr_warn("forcing remaining tasks to the patched state\n");
+
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, task)
+		klp_update_patch_state(task);
+	read_unlock(&tasklist_lock);
+
+	for_each_possible_cpu(cpu)
+		klp_update_patch_state(idle_task(cpu));
+
+	/* Set forced flag for patches being removed. */
+	if (klp_target_state == KLP_UNPATCHED)
+		klp_transition_patch->forced = true;
+	else if (klp_transition_patch->replace) {
+		klp_for_each_patch(patch) {
+			if (patch != klp_transition_patch)
+				patch->forced = true;
+		}
+	}
+}
diff --git a/kernel/livepatch/transition.h b/kernel/livepatch/transition.h
new file mode 100644
index 000000000..322db1623
--- /dev/null
+++ b/kernel/livepatch/transition.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LIVEPATCH_TRANSITION_H
+#define _LIVEPATCH_TRANSITION_H
+
+#include <linux/livepatch.h>
+
+extern struct klp_patch *klp_transition_patch;
+
+void klp_init_transition(struct klp_patch *patch, int state);
+void klp_cancel_transition(void);
+void klp_start_transition(void);
+void klp_try_complete_transition(void);
+void klp_reverse_transition(void);
+void klp_force_transition(void);
+
+#endif /* _LIVEPATCH_TRANSITION_H */
diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
new file mode 100644
index 000000000..ea925731f
--- /dev/null
+++ b/kernel/locking/Makefile
@@ -0,0 +1,35 @@
+# SPDX-License-Identifier: GPL-2.0
+# Any varying coverage in these files is non-deterministic
+# and is generally not a function of system call inputs.
+KCOV_INSTRUMENT		:= n
+
+obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o
+
+# Avoid recursion lockdep -> sanitizer -> ... -> lockdep.
+KCSAN_SANITIZE_lockdep.o := n
+KMSAN_SANITIZE_lockdep.o := n
+
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_lockdep_proc.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_mutex-debug.o = $(CC_FLAGS_FTRACE)
+endif
+
+obj-$(CONFIG_DEBUG_IRQFLAGS) += irqflag-debug.o
+obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
+obj-$(CONFIG_LOCKDEP) += lockdep.o
+ifeq ($(CONFIG_PROC_FS),y)
+obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
+endif
+obj-$(CONFIG_SMP) += spinlock.o
+obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o
+obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
+obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o
+obj-$(CONFIG_RT_MUTEXES) += rtmutex_api.o
+obj-$(CONFIG_PREEMPT_RT) += spinlock_rt.o ww_rt_mutex.o
+obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
+obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
+obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o
+obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
+obj-$(CONFIG_WW_MUTEX_SELFTEST) += test-ww_mutex.o
+obj-$(CONFIG_LOCK_EVENT_COUNTS) += lock_events.o
diff --git a/kernel/locking/irqflag-debug.c b/kernel/locking/irqflag-debug.c
new file mode 100644
index 000000000..810b50344
--- /dev/null
+++ b/kernel/locking/irqflag-debug.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/bug.h>
+#include <linux/export.h>
+#include <linux/irqflags.h>
+
+noinstr void warn_bogus_irq_restore(void)
+{
+	instrumentation_begin();
+	WARN_ONCE(1, "raw_local_irq_restore() called with IRQs enabled\n");
+	instrumentation_end();
+}
+EXPORT_SYMBOL(warn_bogus_irq_restore);
diff --git a/kernel/locking/lock_events.c b/kernel/locking/lock_events.c
new file mode 100644
index 000000000..fa2c2f951
--- /dev/null
+++ b/kernel/locking/lock_events.c
@@ -0,0 +1,179 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Authors: Waiman Long <waiman.long@hpe.com>
+ */
+
+/*
+ * Collect locking event counts
+ */
+#include <linux/debugfs.h>
+#include <linux/sched.h>
+#include <linux/sched/clock.h>
+#include <linux/fs.h>
+
+#include "lock_events.h"
+
+#undef  LOCK_EVENT
+#define LOCK_EVENT(name)	[LOCKEVENT_ ## name] = #name,
+
+#define LOCK_EVENTS_DIR		"lock_event_counts"
+
+/*
+ * When CONFIG_LOCK_EVENT_COUNTS is enabled, event counts of different
+ * types of locks will be reported under the <debugfs>/lock_event_counts/
+ * directory. See lock_events_list.h for the list of available locking
+ * events.
+ *
+ * Writing to the special ".reset_counts" file will reset all the above
+ * locking event counts. This is a very slow operation and so should not
+ * be done frequently.
+ *
+ * These event counts are implemented as per-cpu variables which are
+ * summed and computed whenever the corresponding debugfs files are read. This
+ * minimizes added overhead making the counts usable even in a production
+ * environment.
+ */
+static const char * const lockevent_names[lockevent_num + 1] = {
+
+#include "lock_events_list.h"
+
+	[LOCKEVENT_reset_cnts] = ".reset_counts",
+};
+
+/*
+ * Per-cpu counts
+ */
+DEFINE_PER_CPU(unsigned long, lockevents[lockevent_num]);
+
+/*
+ * The lockevent_read() function can be overridden.
+ */
+ssize_t __weak lockevent_read(struct file *file, char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	char buf[64];
+	int cpu, id, len;
+	u64 sum = 0;
+
+	/*
+	 * Get the counter ID stored in file->f_inode->i_private
+	 */
+	id = (long)file_inode(file)->i_private;
+
+	if (id >= lockevent_num)
+		return -EBADF;
+
+	for_each_possible_cpu(cpu)
+		sum += per_cpu(lockevents[id], cpu);
+	len = snprintf(buf, sizeof(buf) - 1, "%llu\n", sum);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+/*
+ * Function to handle write request
+ *
+ * When idx = reset_cnts, reset all the counts.
+ */
+static ssize_t lockevent_write(struct file *file, const char __user *user_buf,
+			   size_t count, loff_t *ppos)
+{
+	int cpu;
+
+	/*
+	 * Get the counter ID stored in file->f_inode->i_private
+	 */
+	if ((long)file_inode(file)->i_private != LOCKEVENT_reset_cnts)
+		return count;
+
+	for_each_possible_cpu(cpu) {
+		int i;
+		unsigned long *ptr = per_cpu_ptr(lockevents, cpu);
+
+		for (i = 0 ; i < lockevent_num; i++)
+			WRITE_ONCE(ptr[i], 0);
+	}
+	return count;
+}
+
+/*
+ * Debugfs data structures
+ */
+static const struct file_operations fops_lockevent = {
+	.read = lockevent_read,
+	.write = lockevent_write,
+	.llseek = default_llseek,
+};
+
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+#include <asm/paravirt.h>
+
+static bool __init skip_lockevent(const char *name)
+{
+	static int pv_on __initdata = -1;
+
+	if (pv_on < 0)
+		pv_on = !pv_is_native_spin_unlock();
+	/*
+	 * Skip PV qspinlock events on bare metal.
+	 */
+	if (!pv_on && !memcmp(name, "pv_", 3))
+		return true;
+	return false;
+}
+#else
+static inline bool skip_lockevent(const char *name)
+{
+	return false;
+}
+#endif
+
+/*
+ * Initialize debugfs for the locking event counts.
+ */
+static int __init init_lockevent_counts(void)
+{
+	struct dentry *d_counts = debugfs_create_dir(LOCK_EVENTS_DIR, NULL);
+	int i;
+
+	if (!d_counts)
+		goto out;
+
+	/*
+	 * Create the debugfs files
+	 *
+	 * As reading from and writing to the stat files can be slow, only
+	 * root is allowed to do the read/write to limit impact to system
+	 * performance.
+	 */
+	for (i = 0; i < lockevent_num; i++) {
+		if (skip_lockevent(lockevent_names[i]))
+			continue;
+		if (!debugfs_create_file(lockevent_names[i], 0400, d_counts,
+					 (void *)(long)i, &fops_lockevent))
+			goto fail_undo;
+	}
+
+	if (!debugfs_create_file(lockevent_names[LOCKEVENT_reset_cnts], 0200,
+				 d_counts, (void *)(long)LOCKEVENT_reset_cnts,
+				 &fops_lockevent))
+		goto fail_undo;
+
+	return 0;
+fail_undo:
+	debugfs_remove_recursive(d_counts);
+out:
+	pr_warn("Could not create '%s' debugfs entries\n", LOCK_EVENTS_DIR);
+	return -ENOMEM;
+}
+fs_initcall(init_lockevent_counts);
diff --git a/kernel/locking/lock_events.h b/kernel/locking/lock_events.h
new file mode 100644
index 000000000..8c7e7d25f
--- /dev/null
+++ b/kernel/locking/lock_events.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Authors: Waiman Long <longman@redhat.com>
+ */
+
+#ifndef __LOCKING_LOCK_EVENTS_H
+#define __LOCKING_LOCK_EVENTS_H
+
+enum lock_events {
+
+#include "lock_events_list.h"
+
+	lockevent_num,	/* Total number of lock event counts */
+	LOCKEVENT_reset_cnts = lockevent_num,
+};
+
+#ifdef CONFIG_LOCK_EVENT_COUNTS
+/*
+ * Per-cpu counters
+ */
+DECLARE_PER_CPU(unsigned long, lockevents[lockevent_num]);
+
+/*
+ * Increment the statistical counters. use raw_cpu_inc() because of lower
+ * overhead and we don't care if we loose the occasional update.
+ */
+static inline void __lockevent_inc(enum lock_events event, bool cond)
+{
+	if (cond)
+		raw_cpu_inc(lockevents[event]);
+}
+
+#define lockevent_inc(ev)	  __lockevent_inc(LOCKEVENT_ ##ev, true)
+#define lockevent_cond_inc(ev, c) __lockevent_inc(LOCKEVENT_ ##ev, c)
+
+static inline void __lockevent_add(enum lock_events event, int inc)
+{
+	raw_cpu_add(lockevents[event], inc);
+}
+
+#define lockevent_add(ev, c)	__lockevent_add(LOCKEVENT_ ##ev, c)
+
+#else  /* CONFIG_LOCK_EVENT_COUNTS */
+
+#define lockevent_inc(ev)
+#define lockevent_add(ev, c)
+#define lockevent_cond_inc(ev, c)
+
+#endif /* CONFIG_LOCK_EVENT_COUNTS */
+#endif /* __LOCKING_LOCK_EVENTS_H */
diff --git a/kernel/locking/lock_events_list.h b/kernel/locking/lock_events_list.h
new file mode 100644
index 000000000..97fb6f3f8
--- /dev/null
+++ b/kernel/locking/lock_events_list.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Authors: Waiman Long <longman@redhat.com>
+ */
+
+#ifndef LOCK_EVENT
+#define LOCK_EVENT(name)	LOCKEVENT_ ## name,
+#endif
+
+#ifdef CONFIG_QUEUED_SPINLOCKS
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+/*
+ * Locking events for PV qspinlock.
+ */
+LOCK_EVENT(pv_hash_hops)	/* Average # of hops per hashing operation */
+LOCK_EVENT(pv_kick_unlock)	/* # of vCPU kicks issued at unlock time   */
+LOCK_EVENT(pv_kick_wake)	/* # of vCPU kicks for pv_latency_wake	   */
+LOCK_EVENT(pv_latency_kick)	/* Average latency (ns) of vCPU kick	   */
+LOCK_EVENT(pv_latency_wake)	/* Average latency (ns) of kick-to-wakeup  */
+LOCK_EVENT(pv_lock_stealing)	/* # of lock stealing operations	   */
+LOCK_EVENT(pv_spurious_wakeup)	/* # of spurious wakeups in non-head vCPUs */
+LOCK_EVENT(pv_wait_again)	/* # of wait's after queue head vCPU kick  */
+LOCK_EVENT(pv_wait_early)	/* # of early vCPU wait's		   */
+LOCK_EVENT(pv_wait_head)	/* # of vCPU wait's at the queue head	   */
+LOCK_EVENT(pv_wait_node)	/* # of vCPU wait's at non-head queue node */
+#endif /* CONFIG_PARAVIRT_SPINLOCKS */
+
+/*
+ * Locking events for qspinlock
+ *
+ * Subtracting lock_use_node[234] from lock_slowpath will give you
+ * lock_use_node1.
+ */
+LOCK_EVENT(lock_pending)	/* # of locking ops via pending code	     */
+LOCK_EVENT(lock_slowpath)	/* # of locking ops via MCS lock queue	     */
+LOCK_EVENT(lock_use_node2)	/* # of locking ops that use 2nd percpu node */
+LOCK_EVENT(lock_use_node3)	/* # of locking ops that use 3rd percpu node */
+LOCK_EVENT(lock_use_node4)	/* # of locking ops that use 4th percpu node */
+LOCK_EVENT(lock_no_node)	/* # of locking ops w/o using percpu node    */
+#endif /* CONFIG_QUEUED_SPINLOCKS */
+
+/*
+ * Locking events for rwsem
+ */
+LOCK_EVENT(rwsem_sleep_reader)	/* # of reader sleeps			*/
+LOCK_EVENT(rwsem_sleep_writer)	/* # of writer sleeps			*/
+LOCK_EVENT(rwsem_wake_reader)	/* # of reader wakeups			*/
+LOCK_EVENT(rwsem_wake_writer)	/* # of writer wakeups			*/
+LOCK_EVENT(rwsem_opt_lock)	/* # of opt-acquired write locks	*/
+LOCK_EVENT(rwsem_opt_fail)	/* # of failed optspins			*/
+LOCK_EVENT(rwsem_opt_nospin)	/* # of disabled optspins		*/
+LOCK_EVENT(rwsem_rlock)		/* # of read locks acquired		*/
+LOCK_EVENT(rwsem_rlock_steal)	/* # of read locks by lock stealing	*/
+LOCK_EVENT(rwsem_rlock_fast)	/* # of fast read locks acquired	*/
+LOCK_EVENT(rwsem_rlock_fail)	/* # of failed read lock acquisitions	*/
+LOCK_EVENT(rwsem_rlock_handoff)	/* # of read lock handoffs		*/
+LOCK_EVENT(rwsem_wlock)		/* # of write locks acquired		*/
+LOCK_EVENT(rwsem_wlock_fail)	/* # of failed write lock acquisitions	*/
+LOCK_EVENT(rwsem_wlock_handoff)	/* # of write lock handoffs		*/
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
new file mode 100644
index 000000000..3b38303ed
--- /dev/null
+++ b/kernel/locking/lockdep.c
@@ -0,0 +1,6595 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/lockdep.c
+ *
+ * Runtime locking correctness validator
+ *
+ * Started by Ingo Molnar:
+ *
+ *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
+ *
+ * this code maps all the lock dependencies as they occur in a live kernel
+ * and will warn about the following classes of locking bugs:
+ *
+ * - lock inversion scenarios
+ * - circular lock dependencies
+ * - hardirq/softirq safe/unsafe locking bugs
+ *
+ * Bugs are reported even if the current locking scenario does not cause
+ * any deadlock at this point.
+ *
+ * I.e. if anytime in the past two locks were taken in a different order,
+ * even if it happened for another task, even if those were different
+ * locks (but of the same class as this lock), this code will detect it.
+ *
+ * Thanks to Arjan van de Ven for coming up with the initial idea of
+ * mapping lock dependencies runtime.
+ */
+#define DISABLE_BRANCH_PROFILING
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/task.h>
+#include <linux/sched/mm.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/interrupt.h>
+#include <linux/stacktrace.h>
+#include <linux/debug_locks.h>
+#include <linux/irqflags.h>
+#include <linux/utsname.h>
+#include <linux/hash.h>
+#include <linux/ftrace.h>
+#include <linux/stringify.h>
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/gfp.h>
+#include <linux/random.h>
+#include <linux/jhash.h>
+#include <linux/nmi.h>
+#include <linux/rcupdate.h>
+#include <linux/kprobes.h>
+#include <linux/lockdep.h>
+#include <linux/context_tracking.h>
+
+#include <asm/sections.h>
+
+#include "lockdep_internals.h"
+
+#include <trace/events/lock.h>
+
+#ifdef CONFIG_PROVE_LOCKING
+static int prove_locking = 1;
+module_param(prove_locking, int, 0644);
+#else
+#define prove_locking 0
+#endif
+
+#ifdef CONFIG_LOCK_STAT
+static int lock_stat = 1;
+module_param(lock_stat, int, 0644);
+#else
+#define lock_stat 0
+#endif
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table kern_lockdep_table[] = {
+#ifdef CONFIG_PROVE_LOCKING
+	{
+		.procname       = "prove_locking",
+		.data           = &prove_locking,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec,
+	},
+#endif /* CONFIG_PROVE_LOCKING */
+#ifdef CONFIG_LOCK_STAT
+	{
+		.procname       = "lock_stat",
+		.data           = &lock_stat,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec,
+	},
+#endif /* CONFIG_LOCK_STAT */
+	{ }
+};
+
+static __init int kernel_lockdep_sysctls_init(void)
+{
+	register_sysctl_init("kernel", kern_lockdep_table);
+	return 0;
+}
+late_initcall(kernel_lockdep_sysctls_init);
+#endif /* CONFIG_SYSCTL */
+
+DEFINE_PER_CPU(unsigned int, lockdep_recursion);
+EXPORT_PER_CPU_SYMBOL_GPL(lockdep_recursion);
+
+static __always_inline bool lockdep_enabled(void)
+{
+	if (!debug_locks)
+		return false;
+
+	if (this_cpu_read(lockdep_recursion))
+		return false;
+
+	if (current->lockdep_recursion)
+		return false;
+
+	return true;
+}
+
+/*
+ * lockdep_lock: protects the lockdep graph, the hashes and the
+ *               class/list/hash allocators.
+ *
+ * This is one of the rare exceptions where it's justified
+ * to use a raw spinlock - we really dont want the spinlock
+ * code to recurse back into the lockdep code...
+ */
+static arch_spinlock_t __lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+static struct task_struct *__owner;
+
+static inline void lockdep_lock(void)
+{
+	DEBUG_LOCKS_WARN_ON(!irqs_disabled());
+
+	__this_cpu_inc(lockdep_recursion);
+	arch_spin_lock(&__lock);
+	__owner = current;
+}
+
+static inline void lockdep_unlock(void)
+{
+	DEBUG_LOCKS_WARN_ON(!irqs_disabled());
+
+	if (debug_locks && DEBUG_LOCKS_WARN_ON(__owner != current))
+		return;
+
+	__owner = NULL;
+	arch_spin_unlock(&__lock);
+	__this_cpu_dec(lockdep_recursion);
+}
+
+static inline bool lockdep_assert_locked(void)
+{
+	return DEBUG_LOCKS_WARN_ON(__owner != current);
+}
+
+static struct task_struct *lockdep_selftest_task_struct;
+
+
+static int graph_lock(void)
+{
+	lockdep_lock();
+	/*
+	 * Make sure that if another CPU detected a bug while
+	 * walking the graph we dont change it (while the other
+	 * CPU is busy printing out stuff with the graph lock
+	 * dropped already)
+	 */
+	if (!debug_locks) {
+		lockdep_unlock();
+		return 0;
+	}
+	return 1;
+}
+
+static inline void graph_unlock(void)
+{
+	lockdep_unlock();
+}
+
+/*
+ * Turn lock debugging off and return with 0 if it was off already,
+ * and also release the graph lock:
+ */
+static inline int debug_locks_off_graph_unlock(void)
+{
+	int ret = debug_locks_off();
+
+	lockdep_unlock();
+
+	return ret;
+}
+
+unsigned long nr_list_entries;
+static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
+static DECLARE_BITMAP(list_entries_in_use, MAX_LOCKDEP_ENTRIES);
+
+/*
+ * All data structures here are protected by the global debug_lock.
+ *
+ * nr_lock_classes is the number of elements of lock_classes[] that is
+ * in use.
+ */
+#define KEYHASH_BITS		(MAX_LOCKDEP_KEYS_BITS - 1)
+#define KEYHASH_SIZE		(1UL << KEYHASH_BITS)
+static struct hlist_head lock_keys_hash[KEYHASH_SIZE];
+unsigned long nr_lock_classes;
+unsigned long nr_zapped_classes;
+unsigned long max_lock_class_idx;
+struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
+DECLARE_BITMAP(lock_classes_in_use, MAX_LOCKDEP_KEYS);
+
+static inline struct lock_class *hlock_class(struct held_lock *hlock)
+{
+	unsigned int class_idx = hlock->class_idx;
+
+	/* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfield */
+	barrier();
+
+	if (!test_bit(class_idx, lock_classes_in_use)) {
+		/*
+		 * Someone passed in garbage, we give up.
+		 */
+		DEBUG_LOCKS_WARN_ON(1);
+		return NULL;
+	}
+
+	/*
+	 * At this point, if the passed hlock->class_idx is still garbage,
+	 * we just have to live with it
+	 */
+	return lock_classes + class_idx;
+}
+
+#ifdef CONFIG_LOCK_STAT
+static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], cpu_lock_stats);
+
+static inline u64 lockstat_clock(void)
+{
+	return local_clock();
+}
+
+static int lock_point(unsigned long points[], unsigned long ip)
+{
+	int i;
+
+	for (i = 0; i < LOCKSTAT_POINTS; i++) {
+		if (points[i] == 0) {
+			points[i] = ip;
+			break;
+		}
+		if (points[i] == ip)
+			break;
+	}
+
+	return i;
+}
+
+static void lock_time_inc(struct lock_time *lt, u64 time)
+{
+	if (time > lt->max)
+		lt->max = time;
+
+	if (time < lt->min || !lt->nr)
+		lt->min = time;
+
+	lt->total += time;
+	lt->nr++;
+}
+
+static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
+{
+	if (!src->nr)
+		return;
+
+	if (src->max > dst->max)
+		dst->max = src->max;
+
+	if (src->min < dst->min || !dst->nr)
+		dst->min = src->min;
+
+	dst->total += src->total;
+	dst->nr += src->nr;
+}
+
+struct lock_class_stats lock_stats(struct lock_class *class)
+{
+	struct lock_class_stats stats;
+	int cpu, i;
+
+	memset(&stats, 0, sizeof(struct lock_class_stats));
+	for_each_possible_cpu(cpu) {
+		struct lock_class_stats *pcs =
+			&per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
+
+		for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
+			stats.contention_point[i] += pcs->contention_point[i];
+
+		for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
+			stats.contending_point[i] += pcs->contending_point[i];
+
+		lock_time_add(&pcs->read_waittime, &stats.read_waittime);
+		lock_time_add(&pcs->write_waittime, &stats.write_waittime);
+
+		lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
+		lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
+
+		for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
+			stats.bounces[i] += pcs->bounces[i];
+	}
+
+	return stats;
+}
+
+void clear_lock_stats(struct lock_class *class)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		struct lock_class_stats *cpu_stats =
+			&per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
+
+		memset(cpu_stats, 0, sizeof(struct lock_class_stats));
+	}
+	memset(class->contention_point, 0, sizeof(class->contention_point));
+	memset(class->contending_point, 0, sizeof(class->contending_point));
+}
+
+static struct lock_class_stats *get_lock_stats(struct lock_class *class)
+{
+	return &this_cpu_ptr(cpu_lock_stats)[class - lock_classes];
+}
+
+static void lock_release_holdtime(struct held_lock *hlock)
+{
+	struct lock_class_stats *stats;
+	u64 holdtime;
+
+	if (!lock_stat)
+		return;
+
+	holdtime = lockstat_clock() - hlock->holdtime_stamp;
+
+	stats = get_lock_stats(hlock_class(hlock));
+	if (hlock->read)
+		lock_time_inc(&stats->read_holdtime, holdtime);
+	else
+		lock_time_inc(&stats->write_holdtime, holdtime);
+}
+#else
+static inline void lock_release_holdtime(struct held_lock *hlock)
+{
+}
+#endif
+
+/*
+ * We keep a global list of all lock classes. The list is only accessed with
+ * the lockdep spinlock lock held. free_lock_classes is a list with free
+ * elements. These elements are linked together by the lock_entry member in
+ * struct lock_class.
+ */
+static LIST_HEAD(all_lock_classes);
+static LIST_HEAD(free_lock_classes);
+
+/**
+ * struct pending_free - information about data structures about to be freed
+ * @zapped: Head of a list with struct lock_class elements.
+ * @lock_chains_being_freed: Bitmap that indicates which lock_chains[] elements
+ *	are about to be freed.
+ */
+struct pending_free {
+	struct list_head zapped;
+	DECLARE_BITMAP(lock_chains_being_freed, MAX_LOCKDEP_CHAINS);
+};
+
+/**
+ * struct delayed_free - data structures used for delayed freeing
+ *
+ * A data structure for delayed freeing of data structures that may be
+ * accessed by RCU readers at the time these were freed.
+ *
+ * @rcu_head:  Used to schedule an RCU callback for freeing data structures.
+ * @index:     Index of @pf to which freed data structures are added.
+ * @scheduled: Whether or not an RCU callback has been scheduled.
+ * @pf:        Array with information about data structures about to be freed.
+ */
+static struct delayed_free {
+	struct rcu_head		rcu_head;
+	int			index;
+	int			scheduled;
+	struct pending_free	pf[2];
+} delayed_free;
+
+/*
+ * The lockdep classes are in a hash-table as well, for fast lookup:
+ */
+#define CLASSHASH_BITS		(MAX_LOCKDEP_KEYS_BITS - 1)
+#define CLASSHASH_SIZE		(1UL << CLASSHASH_BITS)
+#define __classhashfn(key)	hash_long((unsigned long)key, CLASSHASH_BITS)
+#define classhashentry(key)	(classhash_table + __classhashfn((key)))
+
+static struct hlist_head classhash_table[CLASSHASH_SIZE];
+
+/*
+ * We put the lock dependency chains into a hash-table as well, to cache
+ * their existence:
+ */
+#define CHAINHASH_BITS		(MAX_LOCKDEP_CHAINS_BITS-1)
+#define CHAINHASH_SIZE		(1UL << CHAINHASH_BITS)
+#define __chainhashfn(chain)	hash_long(chain, CHAINHASH_BITS)
+#define chainhashentry(chain)	(chainhash_table + __chainhashfn((chain)))
+
+static struct hlist_head chainhash_table[CHAINHASH_SIZE];
+
+/*
+ * the id of held_lock
+ */
+static inline u16 hlock_id(struct held_lock *hlock)
+{
+	BUILD_BUG_ON(MAX_LOCKDEP_KEYS_BITS + 2 > 16);
+
+	return (hlock->class_idx | (hlock->read << MAX_LOCKDEP_KEYS_BITS));
+}
+
+static inline unsigned int chain_hlock_class_idx(u16 hlock_id)
+{
+	return hlock_id & (MAX_LOCKDEP_KEYS - 1);
+}
+
+/*
+ * The hash key of the lock dependency chains is a hash itself too:
+ * it's a hash of all locks taken up to that lock, including that lock.
+ * It's a 64-bit hash, because it's important for the keys to be
+ * unique.
+ */
+static inline u64 iterate_chain_key(u64 key, u32 idx)
+{
+	u32 k0 = key, k1 = key >> 32;
+
+	__jhash_mix(idx, k0, k1); /* Macro that modifies arguments! */
+
+	return k0 | (u64)k1 << 32;
+}
+
+void lockdep_init_task(struct task_struct *task)
+{
+	task->lockdep_depth = 0; /* no locks held yet */
+	task->curr_chain_key = INITIAL_CHAIN_KEY;
+	task->lockdep_recursion = 0;
+}
+
+static __always_inline void lockdep_recursion_inc(void)
+{
+	__this_cpu_inc(lockdep_recursion);
+}
+
+static __always_inline void lockdep_recursion_finish(void)
+{
+	if (WARN_ON_ONCE(__this_cpu_dec_return(lockdep_recursion)))
+		__this_cpu_write(lockdep_recursion, 0);
+}
+
+void lockdep_set_selftest_task(struct task_struct *task)
+{
+	lockdep_selftest_task_struct = task;
+}
+
+/*
+ * Debugging switches:
+ */
+
+#define VERBOSE			0
+#define VERY_VERBOSE		0
+
+#if VERBOSE
+# define HARDIRQ_VERBOSE	1
+# define SOFTIRQ_VERBOSE	1
+#else
+# define HARDIRQ_VERBOSE	0
+# define SOFTIRQ_VERBOSE	0
+#endif
+
+#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE
+/*
+ * Quick filtering for interesting events:
+ */
+static int class_filter(struct lock_class *class)
+{
+#if 0
+	/* Example */
+	if (class->name_version == 1 &&
+			!strcmp(class->name, "lockname"))
+		return 1;
+	if (class->name_version == 1 &&
+			!strcmp(class->name, "&struct->lockfield"))
+		return 1;
+#endif
+	/* Filter everything else. 1 would be to allow everything else */
+	return 0;
+}
+#endif
+
+static int verbose(struct lock_class *class)
+{
+#if VERBOSE
+	return class_filter(class);
+#endif
+	return 0;
+}
+
+static void print_lockdep_off(const char *bug_msg)
+{
+	printk(KERN_DEBUG "%s\n", bug_msg);
+	printk(KERN_DEBUG "turning off the locking correctness validator.\n");
+#ifdef CONFIG_LOCK_STAT
+	printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n");
+#endif
+}
+
+unsigned long nr_stack_trace_entries;
+
+#ifdef CONFIG_PROVE_LOCKING
+/**
+ * struct lock_trace - single stack backtrace
+ * @hash_entry:	Entry in a stack_trace_hash[] list.
+ * @hash:	jhash() of @entries.
+ * @nr_entries:	Number of entries in @entries.
+ * @entries:	Actual stack backtrace.
+ */
+struct lock_trace {
+	struct hlist_node	hash_entry;
+	u32			hash;
+	u32			nr_entries;
+	unsigned long		entries[] __aligned(sizeof(unsigned long));
+};
+#define LOCK_TRACE_SIZE_IN_LONGS				\
+	(sizeof(struct lock_trace) / sizeof(unsigned long))
+/*
+ * Stack-trace: sequence of lock_trace structures. Protected by the graph_lock.
+ */
+static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
+static struct hlist_head stack_trace_hash[STACK_TRACE_HASH_SIZE];
+
+static bool traces_identical(struct lock_trace *t1, struct lock_trace *t2)
+{
+	return t1->hash == t2->hash && t1->nr_entries == t2->nr_entries &&
+		memcmp(t1->entries, t2->entries,
+		       t1->nr_entries * sizeof(t1->entries[0])) == 0;
+}
+
+static struct lock_trace *save_trace(void)
+{
+	struct lock_trace *trace, *t2;
+	struct hlist_head *hash_head;
+	u32 hash;
+	int max_entries;
+
+	BUILD_BUG_ON_NOT_POWER_OF_2(STACK_TRACE_HASH_SIZE);
+	BUILD_BUG_ON(LOCK_TRACE_SIZE_IN_LONGS >= MAX_STACK_TRACE_ENTRIES);
+
+	trace = (struct lock_trace *)(stack_trace + nr_stack_trace_entries);
+	max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries -
+		LOCK_TRACE_SIZE_IN_LONGS;
+
+	if (max_entries <= 0) {
+		if (!debug_locks_off_graph_unlock())
+			return NULL;
+
+		print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
+		dump_stack();
+
+		return NULL;
+	}
+	trace->nr_entries = stack_trace_save(trace->entries, max_entries, 3);
+
+	hash = jhash(trace->entries, trace->nr_entries *
+		     sizeof(trace->entries[0]), 0);
+	trace->hash = hash;
+	hash_head = stack_trace_hash + (hash & (STACK_TRACE_HASH_SIZE - 1));
+	hlist_for_each_entry(t2, hash_head, hash_entry) {
+		if (traces_identical(trace, t2))
+			return t2;
+	}
+	nr_stack_trace_entries += LOCK_TRACE_SIZE_IN_LONGS + trace->nr_entries;
+	hlist_add_head(&trace->hash_entry, hash_head);
+
+	return trace;
+}
+
+/* Return the number of stack traces in the stack_trace[] array. */
+u64 lockdep_stack_trace_count(void)
+{
+	struct lock_trace *trace;
+	u64 c = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(stack_trace_hash); i++) {
+		hlist_for_each_entry(trace, &stack_trace_hash[i], hash_entry) {
+			c++;
+		}
+	}
+
+	return c;
+}
+
+/* Return the number of stack hash chains that have at least one stack trace. */
+u64 lockdep_stack_hash_count(void)
+{
+	u64 c = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(stack_trace_hash); i++)
+		if (!hlist_empty(&stack_trace_hash[i]))
+			c++;
+
+	return c;
+}
+#endif
+
+unsigned int nr_hardirq_chains;
+unsigned int nr_softirq_chains;
+unsigned int nr_process_chains;
+unsigned int max_lockdep_depth;
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+/*
+ * Various lockdep statistics:
+ */
+DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
+#endif
+
+#ifdef CONFIG_PROVE_LOCKING
+/*
+ * Locking printouts:
+ */
+
+#define __USAGE(__STATE)						\
+	[LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W",	\
+	[LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W",		\
+	[LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
+	[LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
+
+static const char *usage_str[] =
+{
+#define LOCKDEP_STATE(__STATE) __USAGE(__STATE)
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+	[LOCK_USED] = "INITIAL USE",
+	[LOCK_USED_READ] = "INITIAL READ USE",
+	/* abused as string storage for verify_lock_unused() */
+	[LOCK_USAGE_STATES] = "IN-NMI",
+};
+#endif
+
+const char *__get_key_name(const struct lockdep_subclass_key *key, char *str)
+{
+	return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
+}
+
+static inline unsigned long lock_flag(enum lock_usage_bit bit)
+{
+	return 1UL << bit;
+}
+
+static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
+{
+	/*
+	 * The usage character defaults to '.' (i.e., irqs disabled and not in
+	 * irq context), which is the safest usage category.
+	 */
+	char c = '.';
+
+	/*
+	 * The order of the following usage checks matters, which will
+	 * result in the outcome character as follows:
+	 *
+	 * - '+': irq is enabled and not in irq context
+	 * - '-': in irq context and irq is disabled
+	 * - '?': in irq context and irq is enabled
+	 */
+	if (class->usage_mask & lock_flag(bit + LOCK_USAGE_DIR_MASK)) {
+		c = '+';
+		if (class->usage_mask & lock_flag(bit))
+			c = '?';
+	} else if (class->usage_mask & lock_flag(bit))
+		c = '-';
+
+	return c;
+}
+
+void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
+{
+	int i = 0;
+
+#define LOCKDEP_STATE(__STATE) 						\
+	usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE);	\
+	usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+
+	usage[i] = '\0';
+}
+
+static void __print_lock_name(struct lock_class *class)
+{
+	char str[KSYM_NAME_LEN];
+	const char *name;
+
+	name = class->name;
+	if (!name) {
+		name = __get_key_name(class->key, str);
+		printk(KERN_CONT "%s", name);
+	} else {
+		printk(KERN_CONT "%s", name);
+		if (class->name_version > 1)
+			printk(KERN_CONT "#%d", class->name_version);
+		if (class->subclass)
+			printk(KERN_CONT "/%d", class->subclass);
+	}
+}
+
+static void print_lock_name(struct lock_class *class)
+{
+	char usage[LOCK_USAGE_CHARS];
+
+	get_usage_chars(class, usage);
+
+	printk(KERN_CONT " (");
+	__print_lock_name(class);
+	printk(KERN_CONT "){%s}-{%d:%d}", usage,
+			class->wait_type_outer ?: class->wait_type_inner,
+			class->wait_type_inner);
+}
+
+static void print_lockdep_cache(struct lockdep_map *lock)
+{
+	const char *name;
+	char str[KSYM_NAME_LEN];
+
+	name = lock->name;
+	if (!name)
+		name = __get_key_name(lock->key->subkeys, str);
+
+	printk(KERN_CONT "%s", name);
+}
+
+static void print_lock(struct held_lock *hlock)
+{
+	/*
+	 * We can be called locklessly through debug_show_all_locks() so be
+	 * extra careful, the hlock might have been released and cleared.
+	 *
+	 * If this indeed happens, lets pretend it does not hurt to continue
+	 * to print the lock unless the hlock class_idx does not point to a
+	 * registered class. The rationale here is: since we don't attempt
+	 * to distinguish whether we are in this situation, if it just
+	 * happened we can't count on class_idx to tell either.
+	 */
+	struct lock_class *lock = hlock_class(hlock);
+
+	if (!lock) {
+		printk(KERN_CONT "<RELEASED>\n");
+		return;
+	}
+
+	printk(KERN_CONT "%px", hlock->instance);
+	print_lock_name(lock);
+	printk(KERN_CONT ", at: %pS\n", (void *)hlock->acquire_ip);
+}
+
+static void lockdep_print_held_locks(struct task_struct *p)
+{
+	int i, depth = READ_ONCE(p->lockdep_depth);
+
+	if (!depth)
+		printk("no locks held by %s/%d.\n", p->comm, task_pid_nr(p));
+	else
+		printk("%d lock%s held by %s/%d:\n", depth,
+		       depth > 1 ? "s" : "", p->comm, task_pid_nr(p));
+	/*
+	 * It's not reliable to print a task's held locks if it's not sleeping
+	 * and it's not the current task.
+	 */
+	if (p != current && task_is_running(p))
+		return;
+	for (i = 0; i < depth; i++) {
+		printk(" #%d: ", i);
+		print_lock(p->held_locks + i);
+	}
+}
+
+static void print_kernel_ident(void)
+{
+	printk("%s %.*s %s\n", init_utsname()->release,
+		(int)strcspn(init_utsname()->version, " "),
+		init_utsname()->version,
+		print_tainted());
+}
+
+static int very_verbose(struct lock_class *class)
+{
+#if VERY_VERBOSE
+	return class_filter(class);
+#endif
+	return 0;
+}
+
+/*
+ * Is this the address of a static object:
+ */
+#ifdef __KERNEL__
+static int static_obj(const void *obj)
+{
+	unsigned long addr = (unsigned long) obj;
+
+	if (is_kernel_core_data(addr))
+		return 1;
+
+	/*
+	 * keys are allowed in the __ro_after_init section.
+	 */
+	if (is_kernel_rodata(addr))
+		return 1;
+
+	/*
+	 * in initdata section and used during bootup only?
+	 * NOTE: On some platforms the initdata section is
+	 * outside of the _stext ... _end range.
+	 */
+	if (system_state < SYSTEM_FREEING_INITMEM &&
+		init_section_contains((void *)addr, 1))
+		return 1;
+
+	/*
+	 * in-kernel percpu var?
+	 */
+	if (is_kernel_percpu_address(addr))
+		return 1;
+
+	/*
+	 * module static or percpu var?
+	 */
+	return is_module_address(addr) || is_module_percpu_address(addr);
+}
+#endif
+
+/*
+ * To make lock name printouts unique, we calculate a unique
+ * class->name_version generation counter. The caller must hold the graph
+ * lock.
+ */
+static int count_matching_names(struct lock_class *new_class)
+{
+	struct lock_class *class;
+	int count = 0;
+
+	if (!new_class->name)
+		return 0;
+
+	list_for_each_entry(class, &all_lock_classes, lock_entry) {
+		if (new_class->key - new_class->subclass == class->key)
+			return class->name_version;
+		if (class->name && !strcmp(class->name, new_class->name))
+			count = max(count, class->name_version);
+	}
+
+	return count + 1;
+}
+
+/* used from NMI context -- must be lockless */
+static noinstr struct lock_class *
+look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass)
+{
+	struct lockdep_subclass_key *key;
+	struct hlist_head *hash_head;
+	struct lock_class *class;
+
+	if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
+		instrumentation_begin();
+		debug_locks_off();
+		printk(KERN_ERR
+			"BUG: looking up invalid subclass: %u\n", subclass);
+		printk(KERN_ERR
+			"turning off the locking correctness validator.\n");
+		dump_stack();
+		instrumentation_end();
+		return NULL;
+	}
+
+	/*
+	 * If it is not initialised then it has never been locked,
+	 * so it won't be present in the hash table.
+	 */
+	if (unlikely(!lock->key))
+		return NULL;
+
+	/*
+	 * NOTE: the class-key must be unique. For dynamic locks, a static
+	 * lock_class_key variable is passed in through the mutex_init()
+	 * (or spin_lock_init()) call - which acts as the key. For static
+	 * locks we use the lock object itself as the key.
+	 */
+	BUILD_BUG_ON(sizeof(struct lock_class_key) >
+			sizeof(struct lockdep_map));
+
+	key = lock->key->subkeys + subclass;
+
+	hash_head = classhashentry(key);
+
+	/*
+	 * We do an RCU walk of the hash, see lockdep_free_key_range().
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return NULL;
+
+	hlist_for_each_entry_rcu_notrace(class, hash_head, hash_entry) {
+		if (class->key == key) {
+			/*
+			 * Huh! same key, different name? Did someone trample
+			 * on some memory? We're most confused.
+			 */
+			WARN_ONCE(class->name != lock->name &&
+				  lock->key != &__lockdep_no_validate__,
+				  "Looking for class \"%s\" with key %ps, but found a different class \"%s\" with the same key\n",
+				  lock->name, lock->key, class->name);
+			return class;
+		}
+	}
+
+	return NULL;
+}
+
+/*
+ * Static locks do not have their class-keys yet - for them the key is
+ * the lock object itself. If the lock is in the per cpu area, the
+ * canonical address of the lock (per cpu offset removed) is used.
+ */
+static bool assign_lock_key(struct lockdep_map *lock)
+{
+	unsigned long can_addr, addr = (unsigned long)lock;
+
+#ifdef __KERNEL__
+	/*
+	 * lockdep_free_key_range() assumes that struct lock_class_key
+	 * objects do not overlap. Since we use the address of lock
+	 * objects as class key for static objects, check whether the
+	 * size of lock_class_key objects does not exceed the size of
+	 * the smallest lock object.
+	 */
+	BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(raw_spinlock_t));
+#endif
+
+	if (__is_kernel_percpu_address(addr, &can_addr))
+		lock->key = (void *)can_addr;
+	else if (__is_module_percpu_address(addr, &can_addr))
+		lock->key = (void *)can_addr;
+	else if (static_obj(lock))
+		lock->key = (void *)lock;
+	else {
+		/* Debug-check: all keys must be persistent! */
+		debug_locks_off();
+		pr_err("INFO: trying to register non-static key.\n");
+		pr_err("The code is fine but needs lockdep annotation, or maybe\n");
+		pr_err("you didn't initialize this object before use?\n");
+		pr_err("turning off the locking correctness validator.\n");
+		dump_stack();
+		return false;
+	}
+
+	return true;
+}
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+
+/* Check whether element @e occurs in list @h */
+static bool in_list(struct list_head *e, struct list_head *h)
+{
+	struct list_head *f;
+
+	list_for_each(f, h) {
+		if (e == f)
+			return true;
+	}
+
+	return false;
+}
+
+/*
+ * Check whether entry @e occurs in any of the locks_after or locks_before
+ * lists.
+ */
+static bool in_any_class_list(struct list_head *e)
+{
+	struct lock_class *class;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(lock_classes); i++) {
+		class = &lock_classes[i];
+		if (in_list(e, &class->locks_after) ||
+		    in_list(e, &class->locks_before))
+			return true;
+	}
+	return false;
+}
+
+static bool class_lock_list_valid(struct lock_class *c, struct list_head *h)
+{
+	struct lock_list *e;
+
+	list_for_each_entry(e, h, entry) {
+		if (e->links_to != c) {
+			printk(KERN_INFO "class %s: mismatch for lock entry %ld; class %s <> %s",
+			       c->name ? : "(?)",
+			       (unsigned long)(e - list_entries),
+			       e->links_to && e->links_to->name ?
+			       e->links_to->name : "(?)",
+			       e->class && e->class->name ? e->class->name :
+			       "(?)");
+			return false;
+		}
+	}
+	return true;
+}
+
+#ifdef CONFIG_PROVE_LOCKING
+static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
+#endif
+
+static bool check_lock_chain_key(struct lock_chain *chain)
+{
+#ifdef CONFIG_PROVE_LOCKING
+	u64 chain_key = INITIAL_CHAIN_KEY;
+	int i;
+
+	for (i = chain->base; i < chain->base + chain->depth; i++)
+		chain_key = iterate_chain_key(chain_key, chain_hlocks[i]);
+	/*
+	 * The 'unsigned long long' casts avoid that a compiler warning
+	 * is reported when building tools/lib/lockdep.
+	 */
+	if (chain->chain_key != chain_key) {
+		printk(KERN_INFO "chain %lld: key %#llx <> %#llx\n",
+		       (unsigned long long)(chain - lock_chains),
+		       (unsigned long long)chain->chain_key,
+		       (unsigned long long)chain_key);
+		return false;
+	}
+#endif
+	return true;
+}
+
+static bool in_any_zapped_class_list(struct lock_class *class)
+{
+	struct pending_free *pf;
+	int i;
+
+	for (i = 0, pf = delayed_free.pf; i < ARRAY_SIZE(delayed_free.pf); i++, pf++) {
+		if (in_list(&class->lock_entry, &pf->zapped))
+			return true;
+	}
+
+	return false;
+}
+
+static bool __check_data_structures(void)
+{
+	struct lock_class *class;
+	struct lock_chain *chain;
+	struct hlist_head *head;
+	struct lock_list *e;
+	int i;
+
+	/* Check whether all classes occur in a lock list. */
+	for (i = 0; i < ARRAY_SIZE(lock_classes); i++) {
+		class = &lock_classes[i];
+		if (!in_list(&class->lock_entry, &all_lock_classes) &&
+		    !in_list(&class->lock_entry, &free_lock_classes) &&
+		    !in_any_zapped_class_list(class)) {
+			printk(KERN_INFO "class %px/%s is not in any class list\n",
+			       class, class->name ? : "(?)");
+			return false;
+		}
+	}
+
+	/* Check whether all classes have valid lock lists. */
+	for (i = 0; i < ARRAY_SIZE(lock_classes); i++) {
+		class = &lock_classes[i];
+		if (!class_lock_list_valid(class, &class->locks_before))
+			return false;
+		if (!class_lock_list_valid(class, &class->locks_after))
+			return false;
+	}
+
+	/* Check the chain_key of all lock chains. */
+	for (i = 0; i < ARRAY_SIZE(chainhash_table); i++) {
+		head = chainhash_table + i;
+		hlist_for_each_entry_rcu(chain, head, entry) {
+			if (!check_lock_chain_key(chain))
+				return false;
+		}
+	}
+
+	/*
+	 * Check whether all list entries that are in use occur in a class
+	 * lock list.
+	 */
+	for_each_set_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) {
+		e = list_entries + i;
+		if (!in_any_class_list(&e->entry)) {
+			printk(KERN_INFO "list entry %d is not in any class list; class %s <> %s\n",
+			       (unsigned int)(e - list_entries),
+			       e->class->name ? : "(?)",
+			       e->links_to->name ? : "(?)");
+			return false;
+		}
+	}
+
+	/*
+	 * Check whether all list entries that are not in use do not occur in
+	 * a class lock list.
+	 */
+	for_each_clear_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) {
+		e = list_entries + i;
+		if (in_any_class_list(&e->entry)) {
+			printk(KERN_INFO "list entry %d occurs in a class list; class %s <> %s\n",
+			       (unsigned int)(e - list_entries),
+			       e->class && e->class->name ? e->class->name :
+			       "(?)",
+			       e->links_to && e->links_to->name ?
+			       e->links_to->name : "(?)");
+			return false;
+		}
+	}
+
+	return true;
+}
+
+int check_consistency = 0;
+module_param(check_consistency, int, 0644);
+
+static void check_data_structures(void)
+{
+	static bool once = false;
+
+	if (check_consistency && !once) {
+		if (!__check_data_structures()) {
+			once = true;
+			WARN_ON(once);
+		}
+	}
+}
+
+#else /* CONFIG_DEBUG_LOCKDEP */
+
+static inline void check_data_structures(void) { }
+
+#endif /* CONFIG_DEBUG_LOCKDEP */
+
+static void init_chain_block_buckets(void);
+
+/*
+ * Initialize the lock_classes[] array elements, the free_lock_classes list
+ * and also the delayed_free structure.
+ */
+static void init_data_structures_once(void)
+{
+	static bool __read_mostly ds_initialized, rcu_head_initialized;
+	int i;
+
+	if (likely(rcu_head_initialized))
+		return;
+
+	if (system_state >= SYSTEM_SCHEDULING) {
+		init_rcu_head(&delayed_free.rcu_head);
+		rcu_head_initialized = true;
+	}
+
+	if (ds_initialized)
+		return;
+
+	ds_initialized = true;
+
+	INIT_LIST_HEAD(&delayed_free.pf[0].zapped);
+	INIT_LIST_HEAD(&delayed_free.pf[1].zapped);
+
+	for (i = 0; i < ARRAY_SIZE(lock_classes); i++) {
+		list_add_tail(&lock_classes[i].lock_entry, &free_lock_classes);
+		INIT_LIST_HEAD(&lock_classes[i].locks_after);
+		INIT_LIST_HEAD(&lock_classes[i].locks_before);
+	}
+	init_chain_block_buckets();
+}
+
+static inline struct hlist_head *keyhashentry(const struct lock_class_key *key)
+{
+	unsigned long hash = hash_long((uintptr_t)key, KEYHASH_BITS);
+
+	return lock_keys_hash + hash;
+}
+
+/* Register a dynamically allocated key. */
+void lockdep_register_key(struct lock_class_key *key)
+{
+	struct hlist_head *hash_head;
+	struct lock_class_key *k;
+	unsigned long flags;
+
+	if (WARN_ON_ONCE(static_obj(key)))
+		return;
+	hash_head = keyhashentry(key);
+
+	raw_local_irq_save(flags);
+	if (!graph_lock())
+		goto restore_irqs;
+	hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
+		if (WARN_ON_ONCE(k == key))
+			goto out_unlock;
+	}
+	hlist_add_head_rcu(&key->hash_entry, hash_head);
+out_unlock:
+	graph_unlock();
+restore_irqs:
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lockdep_register_key);
+
+/* Check whether a key has been registered as a dynamic key. */
+static bool is_dynamic_key(const struct lock_class_key *key)
+{
+	struct hlist_head *hash_head;
+	struct lock_class_key *k;
+	bool found = false;
+
+	if (WARN_ON_ONCE(static_obj(key)))
+		return false;
+
+	/*
+	 * If lock debugging is disabled lock_keys_hash[] may contain
+	 * pointers to memory that has already been freed. Avoid triggering
+	 * a use-after-free in that case by returning early.
+	 */
+	if (!debug_locks)
+		return true;
+
+	hash_head = keyhashentry(key);
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
+		if (k == key) {
+			found = true;
+			break;
+		}
+	}
+	rcu_read_unlock();
+
+	return found;
+}
+
+/*
+ * Register a lock's class in the hash-table, if the class is not present
+ * yet. Otherwise we look it up. We cache the result in the lock object
+ * itself, so actual lookup of the hash should be once per lock object.
+ */
+static struct lock_class *
+register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
+{
+	struct lockdep_subclass_key *key;
+	struct hlist_head *hash_head;
+	struct lock_class *class;
+	int idx;
+
+	DEBUG_LOCKS_WARN_ON(!irqs_disabled());
+
+	class = look_up_lock_class(lock, subclass);
+	if (likely(class))
+		goto out_set_class_cache;
+
+	if (!lock->key) {
+		if (!assign_lock_key(lock))
+			return NULL;
+	} else if (!static_obj(lock->key) && !is_dynamic_key(lock->key)) {
+		return NULL;
+	}
+
+	key = lock->key->subkeys + subclass;
+	hash_head = classhashentry(key);
+
+	if (!graph_lock()) {
+		return NULL;
+	}
+	/*
+	 * We have to do the hash-walk again, to avoid races
+	 * with another CPU:
+	 */
+	hlist_for_each_entry_rcu(class, hash_head, hash_entry) {
+		if (class->key == key)
+			goto out_unlock_set;
+	}
+
+	init_data_structures_once();
+
+	/* Allocate a new lock class and add it to the hash. */
+	class = list_first_entry_or_null(&free_lock_classes, typeof(*class),
+					 lock_entry);
+	if (!class) {
+		if (!debug_locks_off_graph_unlock()) {
+			return NULL;
+		}
+
+		print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!");
+		dump_stack();
+		return NULL;
+	}
+	nr_lock_classes++;
+	__set_bit(class - lock_classes, lock_classes_in_use);
+	debug_atomic_inc(nr_unused_locks);
+	class->key = key;
+	class->name = lock->name;
+	class->subclass = subclass;
+	WARN_ON_ONCE(!list_empty(&class->locks_before));
+	WARN_ON_ONCE(!list_empty(&class->locks_after));
+	class->name_version = count_matching_names(class);
+	class->wait_type_inner = lock->wait_type_inner;
+	class->wait_type_outer = lock->wait_type_outer;
+	class->lock_type = lock->lock_type;
+	/*
+	 * We use RCU's safe list-add method to make
+	 * parallel walking of the hash-list safe:
+	 */
+	hlist_add_head_rcu(&class->hash_entry, hash_head);
+	/*
+	 * Remove the class from the free list and add it to the global list
+	 * of classes.
+	 */
+	list_move_tail(&class->lock_entry, &all_lock_classes);
+	idx = class - lock_classes;
+	if (idx > max_lock_class_idx)
+		max_lock_class_idx = idx;
+
+	if (verbose(class)) {
+		graph_unlock();
+
+		printk("\nnew class %px: %s", class->key, class->name);
+		if (class->name_version > 1)
+			printk(KERN_CONT "#%d", class->name_version);
+		printk(KERN_CONT "\n");
+		dump_stack();
+
+		if (!graph_lock()) {
+			return NULL;
+		}
+	}
+out_unlock_set:
+	graph_unlock();
+
+out_set_class_cache:
+	if (!subclass || force)
+		lock->class_cache[0] = class;
+	else if (subclass < NR_LOCKDEP_CACHING_CLASSES)
+		lock->class_cache[subclass] = class;
+
+	/*
+	 * Hash collision, did we smoke some? We found a class with a matching
+	 * hash but the subclass -- which is hashed in -- didn't match.
+	 */
+	if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
+		return NULL;
+
+	return class;
+}
+
+#ifdef CONFIG_PROVE_LOCKING
+/*
+ * Allocate a lockdep entry. (assumes the graph_lock held, returns
+ * with NULL on failure)
+ */
+static struct lock_list *alloc_list_entry(void)
+{
+	int idx = find_first_zero_bit(list_entries_in_use,
+				      ARRAY_SIZE(list_entries));
+
+	if (idx >= ARRAY_SIZE(list_entries)) {
+		if (!debug_locks_off_graph_unlock())
+			return NULL;
+
+		print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!");
+		dump_stack();
+		return NULL;
+	}
+	nr_list_entries++;
+	__set_bit(idx, list_entries_in_use);
+	return list_entries + idx;
+}
+
+/*
+ * Add a new dependency to the head of the list:
+ */
+static int add_lock_to_list(struct lock_class *this,
+			    struct lock_class *links_to, struct list_head *head,
+			    u16 distance, u8 dep,
+			    const struct lock_trace *trace)
+{
+	struct lock_list *entry;
+	/*
+	 * Lock not present yet - get a new dependency struct and
+	 * add it to the list:
+	 */
+	entry = alloc_list_entry();
+	if (!entry)
+		return 0;
+
+	entry->class = this;
+	entry->links_to = links_to;
+	entry->dep = dep;
+	entry->distance = distance;
+	entry->trace = trace;
+	/*
+	 * Both allocation and removal are done under the graph lock; but
+	 * iteration is under RCU-sched; see look_up_lock_class() and
+	 * lockdep_free_key_range().
+	 */
+	list_add_tail_rcu(&entry->entry, head);
+
+	return 1;
+}
+
+/*
+ * For good efficiency of modular, we use power of 2
+ */
+#define MAX_CIRCULAR_QUEUE_SIZE		(1UL << CONFIG_LOCKDEP_CIRCULAR_QUEUE_BITS)
+#define CQ_MASK				(MAX_CIRCULAR_QUEUE_SIZE-1)
+
+/*
+ * The circular_queue and helpers are used to implement graph
+ * breadth-first search (BFS) algorithm, by which we can determine
+ * whether there is a path from a lock to another. In deadlock checks,
+ * a path from the next lock to be acquired to a previous held lock
+ * indicates that adding the <prev> -> <next> lock dependency will
+ * produce a circle in the graph. Breadth-first search instead of
+ * depth-first search is used in order to find the shortest (circular)
+ * path.
+ */
+struct circular_queue {
+	struct lock_list *element[MAX_CIRCULAR_QUEUE_SIZE];
+	unsigned int  front, rear;
+};
+
+static struct circular_queue lock_cq;
+
+unsigned int max_bfs_queue_depth;
+
+static unsigned int lockdep_dependency_gen_id;
+
+static inline void __cq_init(struct circular_queue *cq)
+{
+	cq->front = cq->rear = 0;
+	lockdep_dependency_gen_id++;
+}
+
+static inline int __cq_empty(struct circular_queue *cq)
+{
+	return (cq->front == cq->rear);
+}
+
+static inline int __cq_full(struct circular_queue *cq)
+{
+	return ((cq->rear + 1) & CQ_MASK) == cq->front;
+}
+
+static inline int __cq_enqueue(struct circular_queue *cq, struct lock_list *elem)
+{
+	if (__cq_full(cq))
+		return -1;
+
+	cq->element[cq->rear] = elem;
+	cq->rear = (cq->rear + 1) & CQ_MASK;
+	return 0;
+}
+
+/*
+ * Dequeue an element from the circular_queue, return a lock_list if
+ * the queue is not empty, or NULL if otherwise.
+ */
+static inline struct lock_list * __cq_dequeue(struct circular_queue *cq)
+{
+	struct lock_list * lock;
+
+	if (__cq_empty(cq))
+		return NULL;
+
+	lock = cq->element[cq->front];
+	cq->front = (cq->front + 1) & CQ_MASK;
+
+	return lock;
+}
+
+static inline unsigned int  __cq_get_elem_count(struct circular_queue *cq)
+{
+	return (cq->rear - cq->front) & CQ_MASK;
+}
+
+static inline void mark_lock_accessed(struct lock_list *lock)
+{
+	lock->class->dep_gen_id = lockdep_dependency_gen_id;
+}
+
+static inline void visit_lock_entry(struct lock_list *lock,
+				    struct lock_list *parent)
+{
+	lock->parent = parent;
+}
+
+static inline unsigned long lock_accessed(struct lock_list *lock)
+{
+	return lock->class->dep_gen_id == lockdep_dependency_gen_id;
+}
+
+static inline struct lock_list *get_lock_parent(struct lock_list *child)
+{
+	return child->parent;
+}
+
+static inline int get_lock_depth(struct lock_list *child)
+{
+	int depth = 0;
+	struct lock_list *parent;
+
+	while ((parent = get_lock_parent(child))) {
+		child = parent;
+		depth++;
+	}
+	return depth;
+}
+
+/*
+ * Return the forward or backward dependency list.
+ *
+ * @lock:   the lock_list to get its class's dependency list
+ * @offset: the offset to struct lock_class to determine whether it is
+ *          locks_after or locks_before
+ */
+static inline struct list_head *get_dep_list(struct lock_list *lock, int offset)
+{
+	void *lock_class = lock->class;
+
+	return lock_class + offset;
+}
+/*
+ * Return values of a bfs search:
+ *
+ * BFS_E* indicates an error
+ * BFS_R* indicates a result (match or not)
+ *
+ * BFS_EINVALIDNODE: Find a invalid node in the graph.
+ *
+ * BFS_EQUEUEFULL: The queue is full while doing the bfs.
+ *
+ * BFS_RMATCH: Find the matched node in the graph, and put that node into
+ *             *@target_entry.
+ *
+ * BFS_RNOMATCH: Haven't found the matched node and keep *@target_entry
+ *               _unchanged_.
+ */
+enum bfs_result {
+	BFS_EINVALIDNODE = -2,
+	BFS_EQUEUEFULL = -1,
+	BFS_RMATCH = 0,
+	BFS_RNOMATCH = 1,
+};
+
+/*
+ * bfs_result < 0 means error
+ */
+static inline bool bfs_error(enum bfs_result res)
+{
+	return res < 0;
+}
+
+/*
+ * DEP_*_BIT in lock_list::dep
+ *
+ * For dependency @prev -> @next:
+ *
+ *   SR: @prev is shared reader (->read != 0) and @next is recursive reader
+ *       (->read == 2)
+ *   ER: @prev is exclusive locker (->read == 0) and @next is recursive reader
+ *   SN: @prev is shared reader and @next is non-recursive locker (->read != 2)
+ *   EN: @prev is exclusive locker and @next is non-recursive locker
+ *
+ * Note that we define the value of DEP_*_BITs so that:
+ *   bit0 is prev->read == 0
+ *   bit1 is next->read != 2
+ */
+#define DEP_SR_BIT (0 + (0 << 1)) /* 0 */
+#define DEP_ER_BIT (1 + (0 << 1)) /* 1 */
+#define DEP_SN_BIT (0 + (1 << 1)) /* 2 */
+#define DEP_EN_BIT (1 + (1 << 1)) /* 3 */
+
+#define DEP_SR_MASK (1U << (DEP_SR_BIT))
+#define DEP_ER_MASK (1U << (DEP_ER_BIT))
+#define DEP_SN_MASK (1U << (DEP_SN_BIT))
+#define DEP_EN_MASK (1U << (DEP_EN_BIT))
+
+static inline unsigned int
+__calc_dep_bit(struct held_lock *prev, struct held_lock *next)
+{
+	return (prev->read == 0) + ((next->read != 2) << 1);
+}
+
+static inline u8 calc_dep(struct held_lock *prev, struct held_lock *next)
+{
+	return 1U << __calc_dep_bit(prev, next);
+}
+
+/*
+ * calculate the dep_bit for backwards edges. We care about whether @prev is
+ * shared and whether @next is recursive.
+ */
+static inline unsigned int
+__calc_dep_bitb(struct held_lock *prev, struct held_lock *next)
+{
+	return (next->read != 2) + ((prev->read == 0) << 1);
+}
+
+static inline u8 calc_depb(struct held_lock *prev, struct held_lock *next)
+{
+	return 1U << __calc_dep_bitb(prev, next);
+}
+
+/*
+ * Initialize a lock_list entry @lock belonging to @class as the root for a BFS
+ * search.
+ */
+static inline void __bfs_init_root(struct lock_list *lock,
+				   struct lock_class *class)
+{
+	lock->class = class;
+	lock->parent = NULL;
+	lock->only_xr = 0;
+}
+
+/*
+ * Initialize a lock_list entry @lock based on a lock acquisition @hlock as the
+ * root for a BFS search.
+ *
+ * ->only_xr of the initial lock node is set to @hlock->read == 2, to make sure
+ * that <prev> -> @hlock and @hlock -> <whatever __bfs() found> is not -(*R)->
+ * and -(S*)->.
+ */
+static inline void bfs_init_root(struct lock_list *lock,
+				 struct held_lock *hlock)
+{
+	__bfs_init_root(lock, hlock_class(hlock));
+	lock->only_xr = (hlock->read == 2);
+}
+
+/*
+ * Similar to bfs_init_root() but initialize the root for backwards BFS.
+ *
+ * ->only_xr of the initial lock node is set to @hlock->read != 0, to make sure
+ * that <next> -> @hlock and @hlock -> <whatever backwards BFS found> is not
+ * -(*S)-> and -(R*)-> (reverse order of -(*R)-> and -(S*)->).
+ */
+static inline void bfs_init_rootb(struct lock_list *lock,
+				  struct held_lock *hlock)
+{
+	__bfs_init_root(lock, hlock_class(hlock));
+	lock->only_xr = (hlock->read != 0);
+}
+
+static inline struct lock_list *__bfs_next(struct lock_list *lock, int offset)
+{
+	if (!lock || !lock->parent)
+		return NULL;
+
+	return list_next_or_null_rcu(get_dep_list(lock->parent, offset),
+				     &lock->entry, struct lock_list, entry);
+}
+
+/*
+ * Breadth-First Search to find a strong path in the dependency graph.
+ *
+ * @source_entry: the source of the path we are searching for.
+ * @data: data used for the second parameter of @match function
+ * @match: match function for the search
+ * @target_entry: pointer to the target of a matched path
+ * @offset: the offset to struct lock_class to determine whether it is
+ *          locks_after or locks_before
+ *
+ * We may have multiple edges (considering different kinds of dependencies,
+ * e.g. ER and SN) between two nodes in the dependency graph. But
+ * only the strong dependency path in the graph is relevant to deadlocks. A
+ * strong dependency path is a dependency path that doesn't have two adjacent
+ * dependencies as -(*R)-> -(S*)->, please see:
+ *
+ *         Documentation/locking/lockdep-design.rst
+ *
+ * for more explanation of the definition of strong dependency paths
+ *
+ * In __bfs(), we only traverse in the strong dependency path:
+ *
+ *     In lock_list::only_xr, we record whether the previous dependency only
+ *     has -(*R)-> in the search, and if it does (prev only has -(*R)->), we
+ *     filter out any -(S*)-> in the current dependency and after that, the
+ *     ->only_xr is set according to whether we only have -(*R)-> left.
+ */
+static enum bfs_result __bfs(struct lock_list *source_entry,
+			     void *data,
+			     bool (*match)(struct lock_list *entry, void *data),
+			     bool (*skip)(struct lock_list *entry, void *data),
+			     struct lock_list **target_entry,
+			     int offset)
+{
+	struct circular_queue *cq = &lock_cq;
+	struct lock_list *lock = NULL;
+	struct lock_list *entry;
+	struct list_head *head;
+	unsigned int cq_depth;
+	bool first;
+
+	lockdep_assert_locked();
+
+	__cq_init(cq);
+	__cq_enqueue(cq, source_entry);
+
+	while ((lock = __bfs_next(lock, offset)) || (lock = __cq_dequeue(cq))) {
+		if (!lock->class)
+			return BFS_EINVALIDNODE;
+
+		/*
+		 * Step 1: check whether we already finish on this one.
+		 *
+		 * If we have visited all the dependencies from this @lock to
+		 * others (iow, if we have visited all lock_list entries in
+		 * @lock->class->locks_{after,before}) we skip, otherwise go
+		 * and visit all the dependencies in the list and mark this
+		 * list accessed.
+		 */
+		if (lock_accessed(lock))
+			continue;
+		else
+			mark_lock_accessed(lock);
+
+		/*
+		 * Step 2: check whether prev dependency and this form a strong
+		 *         dependency path.
+		 */
+		if (lock->parent) { /* Parent exists, check prev dependency */
+			u8 dep = lock->dep;
+			bool prev_only_xr = lock->parent->only_xr;
+
+			/*
+			 * Mask out all -(S*)-> if we only have *R in previous
+			 * step, because -(*R)-> -(S*)-> don't make up a strong
+			 * dependency.
+			 */
+			if (prev_only_xr)
+				dep &= ~(DEP_SR_MASK | DEP_SN_MASK);
+
+			/* If nothing left, we skip */
+			if (!dep)
+				continue;
+
+			/* If there are only -(*R)-> left, set that for the next step */
+			lock->only_xr = !(dep & (DEP_SN_MASK | DEP_EN_MASK));
+		}
+
+		/*
+		 * Step 3: we haven't visited this and there is a strong
+		 *         dependency path to this, so check with @match.
+		 *         If @skip is provide and returns true, we skip this
+		 *         lock (and any path this lock is in).
+		 */
+		if (skip && skip(lock, data))
+			continue;
+
+		if (match(lock, data)) {
+			*target_entry = lock;
+			return BFS_RMATCH;
+		}
+
+		/*
+		 * Step 4: if not match, expand the path by adding the
+		 *         forward or backwards dependencies in the search
+		 *
+		 */
+		first = true;
+		head = get_dep_list(lock, offset);
+		list_for_each_entry_rcu(entry, head, entry) {
+			visit_lock_entry(entry, lock);
+
+			/*
+			 * Note we only enqueue the first of the list into the
+			 * queue, because we can always find a sibling
+			 * dependency from one (see __bfs_next()), as a result
+			 * the space of queue is saved.
+			 */
+			if (!first)
+				continue;
+
+			first = false;
+
+			if (__cq_enqueue(cq, entry))
+				return BFS_EQUEUEFULL;
+
+			cq_depth = __cq_get_elem_count(cq);
+			if (max_bfs_queue_depth < cq_depth)
+				max_bfs_queue_depth = cq_depth;
+		}
+	}
+
+	return BFS_RNOMATCH;
+}
+
+static inline enum bfs_result
+__bfs_forwards(struct lock_list *src_entry,
+	       void *data,
+	       bool (*match)(struct lock_list *entry, void *data),
+	       bool (*skip)(struct lock_list *entry, void *data),
+	       struct lock_list **target_entry)
+{
+	return __bfs(src_entry, data, match, skip, target_entry,
+		     offsetof(struct lock_class, locks_after));
+
+}
+
+static inline enum bfs_result
+__bfs_backwards(struct lock_list *src_entry,
+		void *data,
+		bool (*match)(struct lock_list *entry, void *data),
+	       bool (*skip)(struct lock_list *entry, void *data),
+		struct lock_list **target_entry)
+{
+	return __bfs(src_entry, data, match, skip, target_entry,
+		     offsetof(struct lock_class, locks_before));
+
+}
+
+static void print_lock_trace(const struct lock_trace *trace,
+			     unsigned int spaces)
+{
+	stack_trace_print(trace->entries, trace->nr_entries, spaces);
+}
+
+/*
+ * Print a dependency chain entry (this is only done when a deadlock
+ * has been detected):
+ */
+static noinline void
+print_circular_bug_entry(struct lock_list *target, int depth)
+{
+	if (debug_locks_silent)
+		return;
+	printk("\n-> #%u", depth);
+	print_lock_name(target->class);
+	printk(KERN_CONT ":\n");
+	print_lock_trace(target->trace, 6);
+}
+
+static void
+print_circular_lock_scenario(struct held_lock *src,
+			     struct held_lock *tgt,
+			     struct lock_list *prt)
+{
+	struct lock_class *source = hlock_class(src);
+	struct lock_class *target = hlock_class(tgt);
+	struct lock_class *parent = prt->class;
+
+	/*
+	 * A direct locking problem where unsafe_class lock is taken
+	 * directly by safe_class lock, then all we need to show
+	 * is the deadlock scenario, as it is obvious that the
+	 * unsafe lock is taken under the safe lock.
+	 *
+	 * But if there is a chain instead, where the safe lock takes
+	 * an intermediate lock (middle_class) where this lock is
+	 * not the same as the safe lock, then the lock chain is
+	 * used to describe the problem. Otherwise we would need
+	 * to show a different CPU case for each link in the chain
+	 * from the safe_class lock to the unsafe_class lock.
+	 */
+	if (parent != source) {
+		printk("Chain exists of:\n  ");
+		__print_lock_name(source);
+		printk(KERN_CONT " --> ");
+		__print_lock_name(parent);
+		printk(KERN_CONT " --> ");
+		__print_lock_name(target);
+		printk(KERN_CONT "\n\n");
+	}
+
+	printk(" Possible unsafe locking scenario:\n\n");
+	printk("       CPU0                    CPU1\n");
+	printk("       ----                    ----\n");
+	printk("  lock(");
+	__print_lock_name(target);
+	printk(KERN_CONT ");\n");
+	printk("                               lock(");
+	__print_lock_name(parent);
+	printk(KERN_CONT ");\n");
+	printk("                               lock(");
+	__print_lock_name(target);
+	printk(KERN_CONT ");\n");
+	printk("  lock(");
+	__print_lock_name(source);
+	printk(KERN_CONT ");\n");
+	printk("\n *** DEADLOCK ***\n\n");
+}
+
+/*
+ * When a circular dependency is detected, print the
+ * header first:
+ */
+static noinline void
+print_circular_bug_header(struct lock_list *entry, unsigned int depth,
+			struct held_lock *check_src,
+			struct held_lock *check_tgt)
+{
+	struct task_struct *curr = current;
+
+	if (debug_locks_silent)
+		return;
+
+	pr_warn("\n");
+	pr_warn("======================================================\n");
+	pr_warn("WARNING: possible circular locking dependency detected\n");
+	print_kernel_ident();
+	pr_warn("------------------------------------------------------\n");
+	pr_warn("%s/%d is trying to acquire lock:\n",
+		curr->comm, task_pid_nr(curr));
+	print_lock(check_src);
+
+	pr_warn("\nbut task is already holding lock:\n");
+
+	print_lock(check_tgt);
+	pr_warn("\nwhich lock already depends on the new lock.\n\n");
+	pr_warn("\nthe existing dependency chain (in reverse order) is:\n");
+
+	print_circular_bug_entry(entry, depth);
+}
+
+/*
+ * We are about to add A -> B into the dependency graph, and in __bfs() a
+ * strong dependency path A -> .. -> B is found: hlock_class equals
+ * entry->class.
+ *
+ * If A -> .. -> B can replace A -> B in any __bfs() search (means the former
+ * is _stronger_ than or equal to the latter), we consider A -> B as redundant.
+ * For example if A -> .. -> B is -(EN)-> (i.e. A -(E*)-> .. -(*N)-> B), and A
+ * -> B is -(ER)-> or -(EN)->, then we don't need to add A -> B into the
+ * dependency graph, as any strong path ..-> A -> B ->.. we can get with
+ * having dependency A -> B, we could already get a equivalent path ..-> A ->
+ * .. -> B -> .. with A -> .. -> B. Therefore A -> B is redundant.
+ *
+ * We need to make sure both the start and the end of A -> .. -> B is not
+ * weaker than A -> B. For the start part, please see the comment in
+ * check_redundant(). For the end part, we need:
+ *
+ * Either
+ *
+ *     a) A -> B is -(*R)-> (everything is not weaker than that)
+ *
+ * or
+ *
+ *     b) A -> .. -> B is -(*N)-> (nothing is stronger than this)
+ *
+ */
+static inline bool hlock_equal(struct lock_list *entry, void *data)
+{
+	struct held_lock *hlock = (struct held_lock *)data;
+
+	return hlock_class(hlock) == entry->class && /* Found A -> .. -> B */
+	       (hlock->read == 2 ||  /* A -> B is -(*R)-> */
+		!entry->only_xr); /* A -> .. -> B is -(*N)-> */
+}
+
+/*
+ * We are about to add B -> A into the dependency graph, and in __bfs() a
+ * strong dependency path A -> .. -> B is found: hlock_class equals
+ * entry->class.
+ *
+ * We will have a deadlock case (conflict) if A -> .. -> B -> A is a strong
+ * dependency cycle, that means:
+ *
+ * Either
+ *
+ *     a) B -> A is -(E*)->
+ *
+ * or
+ *
+ *     b) A -> .. -> B is -(*N)-> (i.e. A -> .. -(*N)-> B)
+ *
+ * as then we don't have -(*R)-> -(S*)-> in the cycle.
+ */
+static inline bool hlock_conflict(struct lock_list *entry, void *data)
+{
+	struct held_lock *hlock = (struct held_lock *)data;
+
+	return hlock_class(hlock) == entry->class && /* Found A -> .. -> B */
+	       (hlock->read == 0 || /* B -> A is -(E*)-> */
+		!entry->only_xr); /* A -> .. -> B is -(*N)-> */
+}
+
+static noinline void print_circular_bug(struct lock_list *this,
+				struct lock_list *target,
+				struct held_lock *check_src,
+				struct held_lock *check_tgt)
+{
+	struct task_struct *curr = current;
+	struct lock_list *parent;
+	struct lock_list *first_parent;
+	int depth;
+
+	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+		return;
+
+	this->trace = save_trace();
+	if (!this->trace)
+		return;
+
+	depth = get_lock_depth(target);
+
+	print_circular_bug_header(target, depth, check_src, check_tgt);
+
+	parent = get_lock_parent(target);
+	first_parent = parent;
+
+	while (parent) {
+		print_circular_bug_entry(parent, --depth);
+		parent = get_lock_parent(parent);
+	}
+
+	printk("\nother info that might help us debug this:\n\n");
+	print_circular_lock_scenario(check_src, check_tgt,
+				     first_parent);
+
+	lockdep_print_held_locks(curr);
+
+	printk("\nstack backtrace:\n");
+	dump_stack();
+}
+
+static noinline void print_bfs_bug(int ret)
+{
+	if (!debug_locks_off_graph_unlock())
+		return;
+
+	/*
+	 * Breadth-first-search failed, graph got corrupted?
+	 */
+	WARN(1, "lockdep bfs error:%d\n", ret);
+}
+
+static bool noop_count(struct lock_list *entry, void *data)
+{
+	(*(unsigned long *)data)++;
+	return false;
+}
+
+static unsigned long __lockdep_count_forward_deps(struct lock_list *this)
+{
+	unsigned long  count = 0;
+	struct lock_list *target_entry;
+
+	__bfs_forwards(this, (void *)&count, noop_count, NULL, &target_entry);
+
+	return count;
+}
+unsigned long lockdep_count_forward_deps(struct lock_class *class)
+{
+	unsigned long ret, flags;
+	struct lock_list this;
+
+	__bfs_init_root(&this, class);
+
+	raw_local_irq_save(flags);
+	lockdep_lock();
+	ret = __lockdep_count_forward_deps(&this);
+	lockdep_unlock();
+	raw_local_irq_restore(flags);
+
+	return ret;
+}
+
+static unsigned long __lockdep_count_backward_deps(struct lock_list *this)
+{
+	unsigned long  count = 0;
+	struct lock_list *target_entry;
+
+	__bfs_backwards(this, (void *)&count, noop_count, NULL, &target_entry);
+
+	return count;
+}
+
+unsigned long lockdep_count_backward_deps(struct lock_class *class)
+{
+	unsigned long ret, flags;
+	struct lock_list this;
+
+	__bfs_init_root(&this, class);
+
+	raw_local_irq_save(flags);
+	lockdep_lock();
+	ret = __lockdep_count_backward_deps(&this);
+	lockdep_unlock();
+	raw_local_irq_restore(flags);
+
+	return ret;
+}
+
+/*
+ * Check that the dependency graph starting at <src> can lead to
+ * <target> or not.
+ */
+static noinline enum bfs_result
+check_path(struct held_lock *target, struct lock_list *src_entry,
+	   bool (*match)(struct lock_list *entry, void *data),
+	   bool (*skip)(struct lock_list *entry, void *data),
+	   struct lock_list **target_entry)
+{
+	enum bfs_result ret;
+
+	ret = __bfs_forwards(src_entry, target, match, skip, target_entry);
+
+	if (unlikely(bfs_error(ret)))
+		print_bfs_bug(ret);
+
+	return ret;
+}
+
+/*
+ * Prove that the dependency graph starting at <src> can not
+ * lead to <target>. If it can, there is a circle when adding
+ * <target> -> <src> dependency.
+ *
+ * Print an error and return BFS_RMATCH if it does.
+ */
+static noinline enum bfs_result
+check_noncircular(struct held_lock *src, struct held_lock *target,
+		  struct lock_trace **const trace)
+{
+	enum bfs_result ret;
+	struct lock_list *target_entry;
+	struct lock_list src_entry;
+
+	bfs_init_root(&src_entry, src);
+
+	debug_atomic_inc(nr_cyclic_checks);
+
+	ret = check_path(target, &src_entry, hlock_conflict, NULL, &target_entry);
+
+	if (unlikely(ret == BFS_RMATCH)) {
+		if (!*trace) {
+			/*
+			 * If save_trace fails here, the printing might
+			 * trigger a WARN but because of the !nr_entries it
+			 * should not do bad things.
+			 */
+			*trace = save_trace();
+		}
+
+		print_circular_bug(&src_entry, target_entry, src, target);
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+
+/*
+ * Forwards and backwards subgraph searching, for the purposes of
+ * proving that two subgraphs can be connected by a new dependency
+ * without creating any illegal irq-safe -> irq-unsafe lock dependency.
+ *
+ * A irq safe->unsafe deadlock happens with the following conditions:
+ *
+ * 1) We have a strong dependency path A -> ... -> B
+ *
+ * 2) and we have ENABLED_IRQ usage of B and USED_IN_IRQ usage of A, therefore
+ *    irq can create a new dependency B -> A (consider the case that a holder
+ *    of B gets interrupted by an irq whose handler will try to acquire A).
+ *
+ * 3) the dependency circle A -> ... -> B -> A we get from 1) and 2) is a
+ *    strong circle:
+ *
+ *      For the usage bits of B:
+ *        a) if A -> B is -(*N)->, then B -> A could be any type, so any
+ *           ENABLED_IRQ usage suffices.
+ *        b) if A -> B is -(*R)->, then B -> A must be -(E*)->, so only
+ *           ENABLED_IRQ_*_READ usage suffices.
+ *
+ *      For the usage bits of A:
+ *        c) if A -> B is -(E*)->, then B -> A could be any type, so any
+ *           USED_IN_IRQ usage suffices.
+ *        d) if A -> B is -(S*)->, then B -> A must be -(*N)->, so only
+ *           USED_IN_IRQ_*_READ usage suffices.
+ */
+
+/*
+ * There is a strong dependency path in the dependency graph: A -> B, and now
+ * we need to decide which usage bit of A should be accumulated to detect
+ * safe->unsafe bugs.
+ *
+ * Note that usage_accumulate() is used in backwards search, so ->only_xr
+ * stands for whether A -> B only has -(S*)-> (in this case ->only_xr is true).
+ *
+ * As above, if only_xr is false, which means A -> B has -(E*)-> dependency
+ * path, any usage of A should be considered. Otherwise, we should only
+ * consider _READ usage.
+ */
+static inline bool usage_accumulate(struct lock_list *entry, void *mask)
+{
+	if (!entry->only_xr)
+		*(unsigned long *)mask |= entry->class->usage_mask;
+	else /* Mask out _READ usage bits */
+		*(unsigned long *)mask |= (entry->class->usage_mask & LOCKF_IRQ);
+
+	return false;
+}
+
+/*
+ * There is a strong dependency path in the dependency graph: A -> B, and now
+ * we need to decide which usage bit of B conflicts with the usage bits of A,
+ * i.e. which usage bit of B may introduce safe->unsafe deadlocks.
+ *
+ * As above, if only_xr is false, which means A -> B has -(*N)-> dependency
+ * path, any usage of B should be considered. Otherwise, we should only
+ * consider _READ usage.
+ */
+static inline bool usage_match(struct lock_list *entry, void *mask)
+{
+	if (!entry->only_xr)
+		return !!(entry->class->usage_mask & *(unsigned long *)mask);
+	else /* Mask out _READ usage bits */
+		return !!((entry->class->usage_mask & LOCKF_IRQ) & *(unsigned long *)mask);
+}
+
+static inline bool usage_skip(struct lock_list *entry, void *mask)
+{
+	/*
+	 * Skip local_lock() for irq inversion detection.
+	 *
+	 * For !RT, local_lock() is not a real lock, so it won't carry any
+	 * dependency.
+	 *
+	 * For RT, an irq inversion happens when we have lock A and B, and on
+	 * some CPU we can have:
+	 *
+	 *	lock(A);
+	 *	<interrupted>
+	 *	  lock(B);
+	 *
+	 * where lock(B) cannot sleep, and we have a dependency B -> ... -> A.
+	 *
+	 * Now we prove local_lock() cannot exist in that dependency. First we
+	 * have the observation for any lock chain L1 -> ... -> Ln, for any
+	 * 1 <= i <= n, Li.inner_wait_type <= L1.inner_wait_type, otherwise
+	 * wait context check will complain. And since B is not a sleep lock,
+	 * therefore B.inner_wait_type >= 2, and since the inner_wait_type of
+	 * local_lock() is 3, which is greater than 2, therefore there is no
+	 * way the local_lock() exists in the dependency B -> ... -> A.
+	 *
+	 * As a result, we will skip local_lock(), when we search for irq
+	 * inversion bugs.
+	 */
+	if (entry->class->lock_type == LD_LOCK_PERCPU) {
+		if (DEBUG_LOCKS_WARN_ON(entry->class->wait_type_inner < LD_WAIT_CONFIG))
+			return false;
+
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * Find a node in the forwards-direction dependency sub-graph starting
+ * at @root->class that matches @bit.
+ *
+ * Return BFS_MATCH if such a node exists in the subgraph, and put that node
+ * into *@target_entry.
+ */
+static enum bfs_result
+find_usage_forwards(struct lock_list *root, unsigned long usage_mask,
+			struct lock_list **target_entry)
+{
+	enum bfs_result result;
+
+	debug_atomic_inc(nr_find_usage_forwards_checks);
+
+	result = __bfs_forwards(root, &usage_mask, usage_match, usage_skip, target_entry);
+
+	return result;
+}
+
+/*
+ * Find a node in the backwards-direction dependency sub-graph starting
+ * at @root->class that matches @bit.
+ */
+static enum bfs_result
+find_usage_backwards(struct lock_list *root, unsigned long usage_mask,
+			struct lock_list **target_entry)
+{
+	enum bfs_result result;
+
+	debug_atomic_inc(nr_find_usage_backwards_checks);
+
+	result = __bfs_backwards(root, &usage_mask, usage_match, usage_skip, target_entry);
+
+	return result;
+}
+
+static void print_lock_class_header(struct lock_class *class, int depth)
+{
+	int bit;
+
+	printk("%*s->", depth, "");
+	print_lock_name(class);
+#ifdef CONFIG_DEBUG_LOCKDEP
+	printk(KERN_CONT " ops: %lu", debug_class_ops_read(class));
+#endif
+	printk(KERN_CONT " {\n");
+
+	for (bit = 0; bit < LOCK_TRACE_STATES; bit++) {
+		if (class->usage_mask & (1 << bit)) {
+			int len = depth;
+
+			len += printk("%*s   %s", depth, "", usage_str[bit]);
+			len += printk(KERN_CONT " at:\n");
+			print_lock_trace(class->usage_traces[bit], len);
+		}
+	}
+	printk("%*s }\n", depth, "");
+
+	printk("%*s ... key      at: [<%px>] %pS\n",
+		depth, "", class->key, class->key);
+}
+
+/*
+ * Dependency path printing:
+ *
+ * After BFS we get a lock dependency path (linked via ->parent of lock_list),
+ * printing out each lock in the dependency path will help on understanding how
+ * the deadlock could happen. Here are some details about dependency path
+ * printing:
+ *
+ * 1)	A lock_list can be either forwards or backwards for a lock dependency,
+ * 	for a lock dependency A -> B, there are two lock_lists:
+ *
+ * 	a)	lock_list in the ->locks_after list of A, whose ->class is B and
+ * 		->links_to is A. In this case, we can say the lock_list is
+ * 		"A -> B" (forwards case).
+ *
+ * 	b)	lock_list in the ->locks_before list of B, whose ->class is A
+ * 		and ->links_to is B. In this case, we can say the lock_list is
+ * 		"B <- A" (bacwards case).
+ *
+ * 	The ->trace of both a) and b) point to the call trace where B was
+ * 	acquired with A held.
+ *
+ * 2)	A "helper" lock_list is introduced during BFS, this lock_list doesn't
+ * 	represent a certain lock dependency, it only provides an initial entry
+ * 	for BFS. For example, BFS may introduce a "helper" lock_list whose
+ * 	->class is A, as a result BFS will search all dependencies starting with
+ * 	A, e.g. A -> B or A -> C.
+ *
+ * 	The notation of a forwards helper lock_list is like "-> A", which means
+ * 	we should search the forwards dependencies starting with "A", e.g A -> B
+ * 	or A -> C.
+ *
+ * 	The notation of a bacwards helper lock_list is like "<- B", which means
+ * 	we should search the backwards dependencies ending with "B", e.g.
+ * 	B <- A or B <- C.
+ */
+
+/*
+ * printk the shortest lock dependencies from @root to @leaf in reverse order.
+ *
+ * We have a lock dependency path as follow:
+ *
+ *    @root                                                                 @leaf
+ *      |                                                                     |
+ *      V                                                                     V
+ *	          ->parent                                   ->parent
+ * | lock_list | <--------- | lock_list | ... | lock_list  | <--------- | lock_list |
+ * |    -> L1  |            | L1 -> L2  | ... |Ln-2 -> Ln-1|            | Ln-1 -> Ln|
+ *
+ * , so it's natural that we start from @leaf and print every ->class and
+ * ->trace until we reach the @root.
+ */
+static void __used
+print_shortest_lock_dependencies(struct lock_list *leaf,
+				 struct lock_list *root)
+{
+	struct lock_list *entry = leaf;
+	int depth;
+
+	/*compute depth from generated tree by BFS*/
+	depth = get_lock_depth(leaf);
+
+	do {
+		print_lock_class_header(entry->class, depth);
+		printk("%*s ... acquired at:\n", depth, "");
+		print_lock_trace(entry->trace, 2);
+		printk("\n");
+
+		if (depth == 0 && (entry != root)) {
+			printk("lockdep:%s bad path found in chain graph\n", __func__);
+			break;
+		}
+
+		entry = get_lock_parent(entry);
+		depth--;
+	} while (entry && (depth >= 0));
+}
+
+/*
+ * printk the shortest lock dependencies from @leaf to @root.
+ *
+ * We have a lock dependency path (from a backwards search) as follow:
+ *
+ *    @leaf                                                                 @root
+ *      |                                                                     |
+ *      V                                                                     V
+ *	          ->parent                                   ->parent
+ * | lock_list | ---------> | lock_list | ... | lock_list  | ---------> | lock_list |
+ * | L2 <- L1  |            | L3 <- L2  | ... | Ln <- Ln-1 |            |    <- Ln  |
+ *
+ * , so when we iterate from @leaf to @root, we actually print the lock
+ * dependency path L1 -> L2 -> .. -> Ln in the non-reverse order.
+ *
+ * Another thing to notice here is that ->class of L2 <- L1 is L1, while the
+ * ->trace of L2 <- L1 is the call trace of L2, in fact we don't have the call
+ * trace of L1 in the dependency path, which is alright, because most of the
+ * time we can figure out where L1 is held from the call trace of L2.
+ */
+static void __used
+print_shortest_lock_dependencies_backwards(struct lock_list *leaf,
+					   struct lock_list *root)
+{
+	struct lock_list *entry = leaf;
+	const struct lock_trace *trace = NULL;
+	int depth;
+
+	/*compute depth from generated tree by BFS*/
+	depth = get_lock_depth(leaf);
+
+	do {
+		print_lock_class_header(entry->class, depth);
+		if (trace) {
+			printk("%*s ... acquired at:\n", depth, "");
+			print_lock_trace(trace, 2);
+			printk("\n");
+		}
+
+		/*
+		 * Record the pointer to the trace for the next lock_list
+		 * entry, see the comments for the function.
+		 */
+		trace = entry->trace;
+
+		if (depth == 0 && (entry != root)) {
+			printk("lockdep:%s bad path found in chain graph\n", __func__);
+			break;
+		}
+
+		entry = get_lock_parent(entry);
+		depth--;
+	} while (entry && (depth >= 0));
+}
+
+static void
+print_irq_lock_scenario(struct lock_list *safe_entry,
+			struct lock_list *unsafe_entry,
+			struct lock_class *prev_class,
+			struct lock_class *next_class)
+{
+	struct lock_class *safe_class = safe_entry->class;
+	struct lock_class *unsafe_class = unsafe_entry->class;
+	struct lock_class *middle_class = prev_class;
+
+	if (middle_class == safe_class)
+		middle_class = next_class;
+
+	/*
+	 * A direct locking problem where unsafe_class lock is taken
+	 * directly by safe_class lock, then all we need to show
+	 * is the deadlock scenario, as it is obvious that the
+	 * unsafe lock is taken under the safe lock.
+	 *
+	 * But if there is a chain instead, where the safe lock takes
+	 * an intermediate lock (middle_class) where this lock is
+	 * not the same as the safe lock, then the lock chain is
+	 * used to describe the problem. Otherwise we would need
+	 * to show a different CPU case for each link in the chain
+	 * from the safe_class lock to the unsafe_class lock.
+	 */
+	if (middle_class != unsafe_class) {
+		printk("Chain exists of:\n  ");
+		__print_lock_name(safe_class);
+		printk(KERN_CONT " --> ");
+		__print_lock_name(middle_class);
+		printk(KERN_CONT " --> ");
+		__print_lock_name(unsafe_class);
+		printk(KERN_CONT "\n\n");
+	}
+
+	printk(" Possible interrupt unsafe locking scenario:\n\n");
+	printk("       CPU0                    CPU1\n");
+	printk("       ----                    ----\n");
+	printk("  lock(");
+	__print_lock_name(unsafe_class);
+	printk(KERN_CONT ");\n");
+	printk("                               local_irq_disable();\n");
+	printk("                               lock(");
+	__print_lock_name(safe_class);
+	printk(KERN_CONT ");\n");
+	printk("                               lock(");
+	__print_lock_name(middle_class);
+	printk(KERN_CONT ");\n");
+	printk("  <Interrupt>\n");
+	printk("    lock(");
+	__print_lock_name(safe_class);
+	printk(KERN_CONT ");\n");
+	printk("\n *** DEADLOCK ***\n\n");
+}
+
+static void
+print_bad_irq_dependency(struct task_struct *curr,
+			 struct lock_list *prev_root,
+			 struct lock_list *next_root,
+			 struct lock_list *backwards_entry,
+			 struct lock_list *forwards_entry,
+			 struct held_lock *prev,
+			 struct held_lock *next,
+			 enum lock_usage_bit bit1,
+			 enum lock_usage_bit bit2,
+			 const char *irqclass)
+{
+	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+		return;
+
+	pr_warn("\n");
+	pr_warn("=====================================================\n");
+	pr_warn("WARNING: %s-safe -> %s-unsafe lock order detected\n",
+		irqclass, irqclass);
+	print_kernel_ident();
+	pr_warn("-----------------------------------------------------\n");
+	pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
+		curr->comm, task_pid_nr(curr),
+		lockdep_hardirq_context(), hardirq_count() >> HARDIRQ_SHIFT,
+		curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
+		lockdep_hardirqs_enabled(),
+		curr->softirqs_enabled);
+	print_lock(next);
+
+	pr_warn("\nand this task is already holding:\n");
+	print_lock(prev);
+	pr_warn("which would create a new lock dependency:\n");
+	print_lock_name(hlock_class(prev));
+	pr_cont(" ->");
+	print_lock_name(hlock_class(next));
+	pr_cont("\n");
+
+	pr_warn("\nbut this new dependency connects a %s-irq-safe lock:\n",
+		irqclass);
+	print_lock_name(backwards_entry->class);
+	pr_warn("\n... which became %s-irq-safe at:\n", irqclass);
+
+	print_lock_trace(backwards_entry->class->usage_traces[bit1], 1);
+
+	pr_warn("\nto a %s-irq-unsafe lock:\n", irqclass);
+	print_lock_name(forwards_entry->class);
+	pr_warn("\n... which became %s-irq-unsafe at:\n", irqclass);
+	pr_warn("...");
+
+	print_lock_trace(forwards_entry->class->usage_traces[bit2], 1);
+
+	pr_warn("\nother info that might help us debug this:\n\n");
+	print_irq_lock_scenario(backwards_entry, forwards_entry,
+				hlock_class(prev), hlock_class(next));
+
+	lockdep_print_held_locks(curr);
+
+	pr_warn("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass);
+	print_shortest_lock_dependencies_backwards(backwards_entry, prev_root);
+
+	pr_warn("\nthe dependencies between the lock to be acquired");
+	pr_warn(" and %s-irq-unsafe lock:\n", irqclass);
+	next_root->trace = save_trace();
+	if (!next_root->trace)
+		return;
+	print_shortest_lock_dependencies(forwards_entry, next_root);
+
+	pr_warn("\nstack backtrace:\n");
+	dump_stack();
+}
+
+static const char *state_names[] = {
+#define LOCKDEP_STATE(__STATE) \
+	__stringify(__STATE),
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static const char *state_rnames[] = {
+#define LOCKDEP_STATE(__STATE) \
+	__stringify(__STATE)"-READ",
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static inline const char *state_name(enum lock_usage_bit bit)
+{
+	if (bit & LOCK_USAGE_READ_MASK)
+		return state_rnames[bit >> LOCK_USAGE_DIR_MASK];
+	else
+		return state_names[bit >> LOCK_USAGE_DIR_MASK];
+}
+
+/*
+ * The bit number is encoded like:
+ *
+ *  bit0: 0 exclusive, 1 read lock
+ *  bit1: 0 used in irq, 1 irq enabled
+ *  bit2-n: state
+ */
+static int exclusive_bit(int new_bit)
+{
+	int state = new_bit & LOCK_USAGE_STATE_MASK;
+	int dir = new_bit & LOCK_USAGE_DIR_MASK;
+
+	/*
+	 * keep state, bit flip the direction and strip read.
+	 */
+	return state | (dir ^ LOCK_USAGE_DIR_MASK);
+}
+
+/*
+ * Observe that when given a bitmask where each bitnr is encoded as above, a
+ * right shift of the mask transforms the individual bitnrs as -1 and
+ * conversely, a left shift transforms into +1 for the individual bitnrs.
+ *
+ * So for all bits whose number have LOCK_ENABLED_* set (bitnr1 == 1), we can
+ * create the mask with those bit numbers using LOCK_USED_IN_* (bitnr1 == 0)
+ * instead by subtracting the bit number by 2, or shifting the mask right by 2.
+ *
+ * Similarly, bitnr1 == 0 becomes bitnr1 == 1 by adding 2, or shifting left 2.
+ *
+ * So split the mask (note that LOCKF_ENABLED_IRQ_ALL|LOCKF_USED_IN_IRQ_ALL is
+ * all bits set) and recompose with bitnr1 flipped.
+ */
+static unsigned long invert_dir_mask(unsigned long mask)
+{
+	unsigned long excl = 0;
+
+	/* Invert dir */
+	excl |= (mask & LOCKF_ENABLED_IRQ_ALL) >> LOCK_USAGE_DIR_MASK;
+	excl |= (mask & LOCKF_USED_IN_IRQ_ALL) << LOCK_USAGE_DIR_MASK;
+
+	return excl;
+}
+
+/*
+ * Note that a LOCK_ENABLED_IRQ_*_READ usage and a LOCK_USED_IN_IRQ_*_READ
+ * usage may cause deadlock too, for example:
+ *
+ * P1				P2
+ * <irq disabled>
+ * write_lock(l1);		<irq enabled>
+ *				read_lock(l2);
+ * write_lock(l2);
+ * 				<in irq>
+ * 				read_lock(l1);
+ *
+ * , in above case, l1 will be marked as LOCK_USED_IN_IRQ_HARDIRQ_READ and l2
+ * will marked as LOCK_ENABLE_IRQ_HARDIRQ_READ, and this is a possible
+ * deadlock.
+ *
+ * In fact, all of the following cases may cause deadlocks:
+ *
+ * 	 LOCK_USED_IN_IRQ_* -> LOCK_ENABLED_IRQ_*
+ * 	 LOCK_USED_IN_IRQ_*_READ -> LOCK_ENABLED_IRQ_*
+ * 	 LOCK_USED_IN_IRQ_* -> LOCK_ENABLED_IRQ_*_READ
+ * 	 LOCK_USED_IN_IRQ_*_READ -> LOCK_ENABLED_IRQ_*_READ
+ *
+ * As a result, to calculate the "exclusive mask", first we invert the
+ * direction (USED_IN/ENABLED) of the original mask, and 1) for all bits with
+ * bitnr0 set (LOCK_*_READ), add those with bitnr0 cleared (LOCK_*). 2) for all
+ * bits with bitnr0 cleared (LOCK_*_READ), add those with bitnr0 set (LOCK_*).
+ */
+static unsigned long exclusive_mask(unsigned long mask)
+{
+	unsigned long excl = invert_dir_mask(mask);
+
+	excl |= (excl & LOCKF_IRQ_READ) >> LOCK_USAGE_READ_MASK;
+	excl |= (excl & LOCKF_IRQ) << LOCK_USAGE_READ_MASK;
+
+	return excl;
+}
+
+/*
+ * Retrieve the _possible_ original mask to which @mask is
+ * exclusive. Ie: this is the opposite of exclusive_mask().
+ * Note that 2 possible original bits can match an exclusive
+ * bit: one has LOCK_USAGE_READ_MASK set, the other has it
+ * cleared. So both are returned for each exclusive bit.
+ */
+static unsigned long original_mask(unsigned long mask)
+{
+	unsigned long excl = invert_dir_mask(mask);
+
+	/* Include read in existing usages */
+	excl |= (excl & LOCKF_IRQ_READ) >> LOCK_USAGE_READ_MASK;
+	excl |= (excl & LOCKF_IRQ) << LOCK_USAGE_READ_MASK;
+
+	return excl;
+}
+
+/*
+ * Find the first pair of bit match between an original
+ * usage mask and an exclusive usage mask.
+ */
+static int find_exclusive_match(unsigned long mask,
+				unsigned long excl_mask,
+				enum lock_usage_bit *bitp,
+				enum lock_usage_bit *excl_bitp)
+{
+	int bit, excl, excl_read;
+
+	for_each_set_bit(bit, &mask, LOCK_USED) {
+		/*
+		 * exclusive_bit() strips the read bit, however,
+		 * LOCK_ENABLED_IRQ_*_READ may cause deadlocks too, so we need
+		 * to search excl | LOCK_USAGE_READ_MASK as well.
+		 */
+		excl = exclusive_bit(bit);
+		excl_read = excl | LOCK_USAGE_READ_MASK;
+		if (excl_mask & lock_flag(excl)) {
+			*bitp = bit;
+			*excl_bitp = excl;
+			return 0;
+		} else if (excl_mask & lock_flag(excl_read)) {
+			*bitp = bit;
+			*excl_bitp = excl_read;
+			return 0;
+		}
+	}
+	return -1;
+}
+
+/*
+ * Prove that the new dependency does not connect a hardirq-safe(-read)
+ * lock with a hardirq-unsafe lock - to achieve this we search
+ * the backwards-subgraph starting at <prev>, and the
+ * forwards-subgraph starting at <next>:
+ */
+static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
+			   struct held_lock *next)
+{
+	unsigned long usage_mask = 0, forward_mask, backward_mask;
+	enum lock_usage_bit forward_bit = 0, backward_bit = 0;
+	struct lock_list *target_entry1;
+	struct lock_list *target_entry;
+	struct lock_list this, that;
+	enum bfs_result ret;
+
+	/*
+	 * Step 1: gather all hard/soft IRQs usages backward in an
+	 * accumulated usage mask.
+	 */
+	bfs_init_rootb(&this, prev);
+
+	ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, usage_skip, NULL);
+	if (bfs_error(ret)) {
+		print_bfs_bug(ret);
+		return 0;
+	}
+
+	usage_mask &= LOCKF_USED_IN_IRQ_ALL;
+	if (!usage_mask)
+		return 1;
+
+	/*
+	 * Step 2: find exclusive uses forward that match the previous
+	 * backward accumulated mask.
+	 */
+	forward_mask = exclusive_mask(usage_mask);
+
+	bfs_init_root(&that, next);
+
+	ret = find_usage_forwards(&that, forward_mask, &target_entry1);
+	if (bfs_error(ret)) {
+		print_bfs_bug(ret);
+		return 0;
+	}
+	if (ret == BFS_RNOMATCH)
+		return 1;
+
+	/*
+	 * Step 3: we found a bad match! Now retrieve a lock from the backward
+	 * list whose usage mask matches the exclusive usage mask from the
+	 * lock found on the forward list.
+	 *
+	 * Note, we should only keep the LOCKF_ENABLED_IRQ_ALL bits, considering
+	 * the follow case:
+	 *
+	 * When trying to add A -> B to the graph, we find that there is a
+	 * hardirq-safe L, that L -> ... -> A, and another hardirq-unsafe M,
+	 * that B -> ... -> M. However M is **softirq-safe**, if we use exact
+	 * invert bits of M's usage_mask, we will find another lock N that is
+	 * **softirq-unsafe** and N -> ... -> A, however N -> .. -> M will not
+	 * cause a inversion deadlock.
+	 */
+	backward_mask = original_mask(target_entry1->class->usage_mask & LOCKF_ENABLED_IRQ_ALL);
+
+	ret = find_usage_backwards(&this, backward_mask, &target_entry);
+	if (bfs_error(ret)) {
+		print_bfs_bug(ret);
+		return 0;
+	}
+	if (DEBUG_LOCKS_WARN_ON(ret == BFS_RNOMATCH))
+		return 1;
+
+	/*
+	 * Step 4: narrow down to a pair of incompatible usage bits
+	 * and report it.
+	 */
+	ret = find_exclusive_match(target_entry->class->usage_mask,
+				   target_entry1->class->usage_mask,
+				   &backward_bit, &forward_bit);
+	if (DEBUG_LOCKS_WARN_ON(ret == -1))
+		return 1;
+
+	print_bad_irq_dependency(curr, &this, &that,
+				 target_entry, target_entry1,
+				 prev, next,
+				 backward_bit, forward_bit,
+				 state_name(backward_bit));
+
+	return 0;
+}
+
+#else
+
+static inline int check_irq_usage(struct task_struct *curr,
+				  struct held_lock *prev, struct held_lock *next)
+{
+	return 1;
+}
+
+static inline bool usage_skip(struct lock_list *entry, void *mask)
+{
+	return false;
+}
+
+#endif /* CONFIG_TRACE_IRQFLAGS */
+
+#ifdef CONFIG_LOCKDEP_SMALL
+/*
+ * Check that the dependency graph starting at <src> can lead to
+ * <target> or not. If it can, <src> -> <target> dependency is already
+ * in the graph.
+ *
+ * Return BFS_RMATCH if it does, or BFS_RNOMATCH if it does not, return BFS_E* if
+ * any error appears in the bfs search.
+ */
+static noinline enum bfs_result
+check_redundant(struct held_lock *src, struct held_lock *target)
+{
+	enum bfs_result ret;
+	struct lock_list *target_entry;
+	struct lock_list src_entry;
+
+	bfs_init_root(&src_entry, src);
+	/*
+	 * Special setup for check_redundant().
+	 *
+	 * To report redundant, we need to find a strong dependency path that
+	 * is equal to or stronger than <src> -> <target>. So if <src> is E,
+	 * we need to let __bfs() only search for a path starting at a -(E*)->,
+	 * we achieve this by setting the initial node's ->only_xr to true in
+	 * that case. And if <prev> is S, we set initial ->only_xr to false
+	 * because both -(S*)-> (equal) and -(E*)-> (stronger) are redundant.
+	 */
+	src_entry.only_xr = src->read == 0;
+
+	debug_atomic_inc(nr_redundant_checks);
+
+	/*
+	 * Note: we skip local_lock() for redundant check, because as the
+	 * comment in usage_skip(), A -> local_lock() -> B and A -> B are not
+	 * the same.
+	 */
+	ret = check_path(target, &src_entry, hlock_equal, usage_skip, &target_entry);
+
+	if (ret == BFS_RMATCH)
+		debug_atomic_inc(nr_redundant);
+
+	return ret;
+}
+
+#else
+
+static inline enum bfs_result
+check_redundant(struct held_lock *src, struct held_lock *target)
+{
+	return BFS_RNOMATCH;
+}
+
+#endif
+
+static void inc_chains(int irq_context)
+{
+	if (irq_context & LOCK_CHAIN_HARDIRQ_CONTEXT)
+		nr_hardirq_chains++;
+	else if (irq_context & LOCK_CHAIN_SOFTIRQ_CONTEXT)
+		nr_softirq_chains++;
+	else
+		nr_process_chains++;
+}
+
+static void dec_chains(int irq_context)
+{
+	if (irq_context & LOCK_CHAIN_HARDIRQ_CONTEXT)
+		nr_hardirq_chains--;
+	else if (irq_context & LOCK_CHAIN_SOFTIRQ_CONTEXT)
+		nr_softirq_chains--;
+	else
+		nr_process_chains--;
+}
+
+static void
+print_deadlock_scenario(struct held_lock *nxt, struct held_lock *prv)
+{
+	struct lock_class *next = hlock_class(nxt);
+	struct lock_class *prev = hlock_class(prv);
+
+	printk(" Possible unsafe locking scenario:\n\n");
+	printk("       CPU0\n");
+	printk("       ----\n");
+	printk("  lock(");
+	__print_lock_name(prev);
+	printk(KERN_CONT ");\n");
+	printk("  lock(");
+	__print_lock_name(next);
+	printk(KERN_CONT ");\n");
+	printk("\n *** DEADLOCK ***\n\n");
+	printk(" May be due to missing lock nesting notation\n\n");
+}
+
+static void
+print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
+		   struct held_lock *next)
+{
+	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+		return;
+
+	pr_warn("\n");
+	pr_warn("============================================\n");
+	pr_warn("WARNING: possible recursive locking detected\n");
+	print_kernel_ident();
+	pr_warn("--------------------------------------------\n");
+	pr_warn("%s/%d is trying to acquire lock:\n",
+		curr->comm, task_pid_nr(curr));
+	print_lock(next);
+	pr_warn("\nbut task is already holding lock:\n");
+	print_lock(prev);
+
+	pr_warn("\nother info that might help us debug this:\n");
+	print_deadlock_scenario(next, prev);
+	lockdep_print_held_locks(curr);
+
+	pr_warn("\nstack backtrace:\n");
+	dump_stack();
+}
+
+/*
+ * Check whether we are holding such a class already.
+ *
+ * (Note that this has to be done separately, because the graph cannot
+ * detect such classes of deadlocks.)
+ *
+ * Returns: 0 on deadlock detected, 1 on OK, 2 if another lock with the same
+ * lock class is held but nest_lock is also held, i.e. we rely on the
+ * nest_lock to avoid the deadlock.
+ */
+static int
+check_deadlock(struct task_struct *curr, struct held_lock *next)
+{
+	struct held_lock *prev;
+	struct held_lock *nest = NULL;
+	int i;
+
+	for (i = 0; i < curr->lockdep_depth; i++) {
+		prev = curr->held_locks + i;
+
+		if (prev->instance == next->nest_lock)
+			nest = prev;
+
+		if (hlock_class(prev) != hlock_class(next))
+			continue;
+
+		/*
+		 * Allow read-after-read recursion of the same
+		 * lock class (i.e. read_lock(lock)+read_lock(lock)):
+		 */
+		if ((next->read == 2) && prev->read)
+			continue;
+
+		/*
+		 * We're holding the nest_lock, which serializes this lock's
+		 * nesting behaviour.
+		 */
+		if (nest)
+			return 2;
+
+		print_deadlock_bug(curr, prev, next);
+		return 0;
+	}
+	return 1;
+}
+
+/*
+ * There was a chain-cache miss, and we are about to add a new dependency
+ * to a previous lock. We validate the following rules:
+ *
+ *  - would the adding of the <prev> -> <next> dependency create a
+ *    circular dependency in the graph? [== circular deadlock]
+ *
+ *  - does the new prev->next dependency connect any hardirq-safe lock
+ *    (in the full backwards-subgraph starting at <prev>) with any
+ *    hardirq-unsafe lock (in the full forwards-subgraph starting at
+ *    <next>)? [== illegal lock inversion with hardirq contexts]
+ *
+ *  - does the new prev->next dependency connect any softirq-safe lock
+ *    (in the full backwards-subgraph starting at <prev>) with any
+ *    softirq-unsafe lock (in the full forwards-subgraph starting at
+ *    <next>)? [== illegal lock inversion with softirq contexts]
+ *
+ * any of these scenarios could lead to a deadlock.
+ *
+ * Then if all the validations pass, we add the forwards and backwards
+ * dependency.
+ */
+static int
+check_prev_add(struct task_struct *curr, struct held_lock *prev,
+	       struct held_lock *next, u16 distance,
+	       struct lock_trace **const trace)
+{
+	struct lock_list *entry;
+	enum bfs_result ret;
+
+	if (!hlock_class(prev)->key || !hlock_class(next)->key) {
+		/*
+		 * The warning statements below may trigger a use-after-free
+		 * of the class name. It is better to trigger a use-after free
+		 * and to have the class name most of the time instead of not
+		 * having the class name available.
+		 */
+		WARN_ONCE(!debug_locks_silent && !hlock_class(prev)->key,
+			  "Detected use-after-free of lock class %px/%s\n",
+			  hlock_class(prev),
+			  hlock_class(prev)->name);
+		WARN_ONCE(!debug_locks_silent && !hlock_class(next)->key,
+			  "Detected use-after-free of lock class %px/%s\n",
+			  hlock_class(next),
+			  hlock_class(next)->name);
+		return 2;
+	}
+
+	/*
+	 * Prove that the new <prev> -> <next> dependency would not
+	 * create a circular dependency in the graph. (We do this by
+	 * a breadth-first search into the graph starting at <next>,
+	 * and check whether we can reach <prev>.)
+	 *
+	 * The search is limited by the size of the circular queue (i.e.,
+	 * MAX_CIRCULAR_QUEUE_SIZE) which keeps track of a breadth of nodes
+	 * in the graph whose neighbours are to be checked.
+	 */
+	ret = check_noncircular(next, prev, trace);
+	if (unlikely(bfs_error(ret) || ret == BFS_RMATCH))
+		return 0;
+
+	if (!check_irq_usage(curr, prev, next))
+		return 0;
+
+	/*
+	 * Is the <prev> -> <next> dependency already present?
+	 *
+	 * (this may occur even though this is a new chain: consider
+	 *  e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3
+	 *  chains - the second one will be new, but L1 already has
+	 *  L2 added to its dependency list, due to the first chain.)
+	 */
+	list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) {
+		if (entry->class == hlock_class(next)) {
+			if (distance == 1)
+				entry->distance = 1;
+			entry->dep |= calc_dep(prev, next);
+
+			/*
+			 * Also, update the reverse dependency in @next's
+			 * ->locks_before list.
+			 *
+			 *  Here we reuse @entry as the cursor, which is fine
+			 *  because we won't go to the next iteration of the
+			 *  outer loop:
+			 *
+			 *  For normal cases, we return in the inner loop.
+			 *
+			 *  If we fail to return, we have inconsistency, i.e.
+			 *  <prev>::locks_after contains <next> while
+			 *  <next>::locks_before doesn't contain <prev>. In
+			 *  that case, we return after the inner and indicate
+			 *  something is wrong.
+			 */
+			list_for_each_entry(entry, &hlock_class(next)->locks_before, entry) {
+				if (entry->class == hlock_class(prev)) {
+					if (distance == 1)
+						entry->distance = 1;
+					entry->dep |= calc_depb(prev, next);
+					return 1;
+				}
+			}
+
+			/* <prev> is not found in <next>::locks_before */
+			return 0;
+		}
+	}
+
+	/*
+	 * Is the <prev> -> <next> link redundant?
+	 */
+	ret = check_redundant(prev, next);
+	if (bfs_error(ret))
+		return 0;
+	else if (ret == BFS_RMATCH)
+		return 2;
+
+	if (!*trace) {
+		*trace = save_trace();
+		if (!*trace)
+			return 0;
+	}
+
+	/*
+	 * Ok, all validations passed, add the new lock
+	 * to the previous lock's dependency list:
+	 */
+	ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
+			       &hlock_class(prev)->locks_after, distance,
+			       calc_dep(prev, next), *trace);
+
+	if (!ret)
+		return 0;
+
+	ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
+			       &hlock_class(next)->locks_before, distance,
+			       calc_depb(prev, next), *trace);
+	if (!ret)
+		return 0;
+
+	return 2;
+}
+
+/*
+ * Add the dependency to all directly-previous locks that are 'relevant'.
+ * The ones that are relevant are (in increasing distance from curr):
+ * all consecutive trylock entries and the final non-trylock entry - or
+ * the end of this context's lock-chain - whichever comes first.
+ */
+static int
+check_prevs_add(struct task_struct *curr, struct held_lock *next)
+{
+	struct lock_trace *trace = NULL;
+	int depth = curr->lockdep_depth;
+	struct held_lock *hlock;
+
+	/*
+	 * Debugging checks.
+	 *
+	 * Depth must not be zero for a non-head lock:
+	 */
+	if (!depth)
+		goto out_bug;
+	/*
+	 * At least two relevant locks must exist for this
+	 * to be a head:
+	 */
+	if (curr->held_locks[depth].irq_context !=
+			curr->held_locks[depth-1].irq_context)
+		goto out_bug;
+
+	for (;;) {
+		u16 distance = curr->lockdep_depth - depth + 1;
+		hlock = curr->held_locks + depth - 1;
+
+		if (hlock->check) {
+			int ret = check_prev_add(curr, hlock, next, distance, &trace);
+			if (!ret)
+				return 0;
+
+			/*
+			 * Stop after the first non-trylock entry,
+			 * as non-trylock entries have added their
+			 * own direct dependencies already, so this
+			 * lock is connected to them indirectly:
+			 */
+			if (!hlock->trylock)
+				break;
+		}
+
+		depth--;
+		/*
+		 * End of lock-stack?
+		 */
+		if (!depth)
+			break;
+		/*
+		 * Stop the search if we cross into another context:
+		 */
+		if (curr->held_locks[depth].irq_context !=
+				curr->held_locks[depth-1].irq_context)
+			break;
+	}
+	return 1;
+out_bug:
+	if (!debug_locks_off_graph_unlock())
+		return 0;
+
+	/*
+	 * Clearly we all shouldn't be here, but since we made it we
+	 * can reliable say we messed up our state. See the above two
+	 * gotos for reasons why we could possibly end up here.
+	 */
+	WARN_ON(1);
+
+	return 0;
+}
+
+struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
+static DECLARE_BITMAP(lock_chains_in_use, MAX_LOCKDEP_CHAINS);
+static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
+unsigned long nr_zapped_lock_chains;
+unsigned int nr_free_chain_hlocks;	/* Free chain_hlocks in buckets */
+unsigned int nr_lost_chain_hlocks;	/* Lost chain_hlocks */
+unsigned int nr_large_chain_blocks;	/* size > MAX_CHAIN_BUCKETS */
+
+/*
+ * The first 2 chain_hlocks entries in the chain block in the bucket
+ * list contains the following meta data:
+ *
+ *   entry[0]:
+ *     Bit    15 - always set to 1 (it is not a class index)
+ *     Bits 0-14 - upper 15 bits of the next block index
+ *   entry[1]    - lower 16 bits of next block index
+ *
+ * A next block index of all 1 bits means it is the end of the list.
+ *
+ * On the unsized bucket (bucket-0), the 3rd and 4th entries contain
+ * the chain block size:
+ *
+ *   entry[2] - upper 16 bits of the chain block size
+ *   entry[3] - lower 16 bits of the chain block size
+ */
+#define MAX_CHAIN_BUCKETS	16
+#define CHAIN_BLK_FLAG		(1U << 15)
+#define CHAIN_BLK_LIST_END	0xFFFFU
+
+static int chain_block_buckets[MAX_CHAIN_BUCKETS];
+
+static inline int size_to_bucket(int size)
+{
+	if (size > MAX_CHAIN_BUCKETS)
+		return 0;
+
+	return size - 1;
+}
+
+/*
+ * Iterate all the chain blocks in a bucket.
+ */
+#define for_each_chain_block(bucket, prev, curr)		\
+	for ((prev) = -1, (curr) = chain_block_buckets[bucket];	\
+	     (curr) >= 0;					\
+	     (prev) = (curr), (curr) = chain_block_next(curr))
+
+/*
+ * next block or -1
+ */
+static inline int chain_block_next(int offset)
+{
+	int next = chain_hlocks[offset];
+
+	WARN_ON_ONCE(!(next & CHAIN_BLK_FLAG));
+
+	if (next == CHAIN_BLK_LIST_END)
+		return -1;
+
+	next &= ~CHAIN_BLK_FLAG;
+	next <<= 16;
+	next |= chain_hlocks[offset + 1];
+
+	return next;
+}
+
+/*
+ * bucket-0 only
+ */
+static inline int chain_block_size(int offset)
+{
+	return (chain_hlocks[offset + 2] << 16) | chain_hlocks[offset + 3];
+}
+
+static inline void init_chain_block(int offset, int next, int bucket, int size)
+{
+	chain_hlocks[offset] = (next >> 16) | CHAIN_BLK_FLAG;
+	chain_hlocks[offset + 1] = (u16)next;
+
+	if (size && !bucket) {
+		chain_hlocks[offset + 2] = size >> 16;
+		chain_hlocks[offset + 3] = (u16)size;
+	}
+}
+
+static inline void add_chain_block(int offset, int size)
+{
+	int bucket = size_to_bucket(size);
+	int next = chain_block_buckets[bucket];
+	int prev, curr;
+
+	if (unlikely(size < 2)) {
+		/*
+		 * We can't store single entries on the freelist. Leak them.
+		 *
+		 * One possible way out would be to uniquely mark them, other
+		 * than with CHAIN_BLK_FLAG, such that we can recover them when
+		 * the block before it is re-added.
+		 */
+		if (size)
+			nr_lost_chain_hlocks++;
+		return;
+	}
+
+	nr_free_chain_hlocks += size;
+	if (!bucket) {
+		nr_large_chain_blocks++;
+
+		/*
+		 * Variable sized, sort large to small.
+		 */
+		for_each_chain_block(0, prev, curr) {
+			if (size >= chain_block_size(curr))
+				break;
+		}
+		init_chain_block(offset, curr, 0, size);
+		if (prev < 0)
+			chain_block_buckets[0] = offset;
+		else
+			init_chain_block(prev, offset, 0, 0);
+		return;
+	}
+	/*
+	 * Fixed size, add to head.
+	 */
+	init_chain_block(offset, next, bucket, size);
+	chain_block_buckets[bucket] = offset;
+}
+
+/*
+ * Only the first block in the list can be deleted.
+ *
+ * For the variable size bucket[0], the first block (the largest one) is
+ * returned, broken up and put back into the pool. So if a chain block of
+ * length > MAX_CHAIN_BUCKETS is ever used and zapped, it will just be
+ * queued up after the primordial chain block and never be used until the
+ * hlock entries in the primordial chain block is almost used up. That
+ * causes fragmentation and reduce allocation efficiency. That can be
+ * monitored by looking at the "large chain blocks" number in lockdep_stats.
+ */
+static inline void del_chain_block(int bucket, int size, int next)
+{
+	nr_free_chain_hlocks -= size;
+	chain_block_buckets[bucket] = next;
+
+	if (!bucket)
+		nr_large_chain_blocks--;
+}
+
+static void init_chain_block_buckets(void)
+{
+	int i;
+
+	for (i = 0; i < MAX_CHAIN_BUCKETS; i++)
+		chain_block_buckets[i] = -1;
+
+	add_chain_block(0, ARRAY_SIZE(chain_hlocks));
+}
+
+/*
+ * Return offset of a chain block of the right size or -1 if not found.
+ *
+ * Fairly simple worst-fit allocator with the addition of a number of size
+ * specific free lists.
+ */
+static int alloc_chain_hlocks(int req)
+{
+	int bucket, curr, size;
+
+	/*
+	 * We rely on the MSB to act as an escape bit to denote freelist
+	 * pointers. Make sure this bit isn't set in 'normal' class_idx usage.
+	 */
+	BUILD_BUG_ON((MAX_LOCKDEP_KEYS-1) & CHAIN_BLK_FLAG);
+
+	init_data_structures_once();
+
+	if (nr_free_chain_hlocks < req)
+		return -1;
+
+	/*
+	 * We require a minimum of 2 (u16) entries to encode a freelist
+	 * 'pointer'.
+	 */
+	req = max(req, 2);
+	bucket = size_to_bucket(req);
+	curr = chain_block_buckets[bucket];
+
+	if (bucket) {
+		if (curr >= 0) {
+			del_chain_block(bucket, req, chain_block_next(curr));
+			return curr;
+		}
+		/* Try bucket 0 */
+		curr = chain_block_buckets[0];
+	}
+
+	/*
+	 * The variable sized freelist is sorted by size; the first entry is
+	 * the largest. Use it if it fits.
+	 */
+	if (curr >= 0) {
+		size = chain_block_size(curr);
+		if (likely(size >= req)) {
+			del_chain_block(0, size, chain_block_next(curr));
+			if (size > req)
+				add_chain_block(curr + req, size - req);
+			return curr;
+		}
+	}
+
+	/*
+	 * Last resort, split a block in a larger sized bucket.
+	 */
+	for (size = MAX_CHAIN_BUCKETS; size > req; size--) {
+		bucket = size_to_bucket(size);
+		curr = chain_block_buckets[bucket];
+		if (curr < 0)
+			continue;
+
+		del_chain_block(bucket, size, chain_block_next(curr));
+		add_chain_block(curr + req, size - req);
+		return curr;
+	}
+
+	return -1;
+}
+
+static inline void free_chain_hlocks(int base, int size)
+{
+	add_chain_block(base, max(size, 2));
+}
+
+struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
+{
+	u16 chain_hlock = chain_hlocks[chain->base + i];
+	unsigned int class_idx = chain_hlock_class_idx(chain_hlock);
+
+	return lock_classes + class_idx;
+}
+
+/*
+ * Returns the index of the first held_lock of the current chain
+ */
+static inline int get_first_held_lock(struct task_struct *curr,
+					struct held_lock *hlock)
+{
+	int i;
+	struct held_lock *hlock_curr;
+
+	for (i = curr->lockdep_depth - 1; i >= 0; i--) {
+		hlock_curr = curr->held_locks + i;
+		if (hlock_curr->irq_context != hlock->irq_context)
+			break;
+
+	}
+
+	return ++i;
+}
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+/*
+ * Returns the next chain_key iteration
+ */
+static u64 print_chain_key_iteration(u16 hlock_id, u64 chain_key)
+{
+	u64 new_chain_key = iterate_chain_key(chain_key, hlock_id);
+
+	printk(" hlock_id:%d -> chain_key:%016Lx",
+		(unsigned int)hlock_id,
+		(unsigned long long)new_chain_key);
+	return new_chain_key;
+}
+
+static void
+print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next)
+{
+	struct held_lock *hlock;
+	u64 chain_key = INITIAL_CHAIN_KEY;
+	int depth = curr->lockdep_depth;
+	int i = get_first_held_lock(curr, hlock_next);
+
+	printk("depth: %u (irq_context %u)\n", depth - i + 1,
+		hlock_next->irq_context);
+	for (; i < depth; i++) {
+		hlock = curr->held_locks + i;
+		chain_key = print_chain_key_iteration(hlock_id(hlock), chain_key);
+
+		print_lock(hlock);
+	}
+
+	print_chain_key_iteration(hlock_id(hlock_next), chain_key);
+	print_lock(hlock_next);
+}
+
+static void print_chain_keys_chain(struct lock_chain *chain)
+{
+	int i;
+	u64 chain_key = INITIAL_CHAIN_KEY;
+	u16 hlock_id;
+
+	printk("depth: %u\n", chain->depth);
+	for (i = 0; i < chain->depth; i++) {
+		hlock_id = chain_hlocks[chain->base + i];
+		chain_key = print_chain_key_iteration(hlock_id, chain_key);
+
+		print_lock_name(lock_classes + chain_hlock_class_idx(hlock_id));
+		printk("\n");
+	}
+}
+
+static void print_collision(struct task_struct *curr,
+			struct held_lock *hlock_next,
+			struct lock_chain *chain)
+{
+	pr_warn("\n");
+	pr_warn("============================\n");
+	pr_warn("WARNING: chain_key collision\n");
+	print_kernel_ident();
+	pr_warn("----------------------------\n");
+	pr_warn("%s/%d: ", current->comm, task_pid_nr(current));
+	pr_warn("Hash chain already cached but the contents don't match!\n");
+
+	pr_warn("Held locks:");
+	print_chain_keys_held_locks(curr, hlock_next);
+
+	pr_warn("Locks in cached chain:");
+	print_chain_keys_chain(chain);
+
+	pr_warn("\nstack backtrace:\n");
+	dump_stack();
+}
+#endif
+
+/*
+ * Checks whether the chain and the current held locks are consistent
+ * in depth and also in content. If they are not it most likely means
+ * that there was a collision during the calculation of the chain_key.
+ * Returns: 0 not passed, 1 passed
+ */
+static int check_no_collision(struct task_struct *curr,
+			struct held_lock *hlock,
+			struct lock_chain *chain)
+{
+#ifdef CONFIG_DEBUG_LOCKDEP
+	int i, j, id;
+
+	i = get_first_held_lock(curr, hlock);
+
+	if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) {
+		print_collision(curr, hlock, chain);
+		return 0;
+	}
+
+	for (j = 0; j < chain->depth - 1; j++, i++) {
+		id = hlock_id(&curr->held_locks[i]);
+
+		if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) {
+			print_collision(curr, hlock, chain);
+			return 0;
+		}
+	}
+#endif
+	return 1;
+}
+
+/*
+ * Given an index that is >= -1, return the index of the next lock chain.
+ * Return -2 if there is no next lock chain.
+ */
+long lockdep_next_lockchain(long i)
+{
+	i = find_next_bit(lock_chains_in_use, ARRAY_SIZE(lock_chains), i + 1);
+	return i < ARRAY_SIZE(lock_chains) ? i : -2;
+}
+
+unsigned long lock_chain_count(void)
+{
+	return bitmap_weight(lock_chains_in_use, ARRAY_SIZE(lock_chains));
+}
+
+/* Must be called with the graph lock held. */
+static struct lock_chain *alloc_lock_chain(void)
+{
+	int idx = find_first_zero_bit(lock_chains_in_use,
+				      ARRAY_SIZE(lock_chains));
+
+	if (unlikely(idx >= ARRAY_SIZE(lock_chains)))
+		return NULL;
+	__set_bit(idx, lock_chains_in_use);
+	return lock_chains + idx;
+}
+
+/*
+ * Adds a dependency chain into chain hashtable. And must be called with
+ * graph_lock held.
+ *
+ * Return 0 if fail, and graph_lock is released.
+ * Return 1 if succeed, with graph_lock held.
+ */
+static inline int add_chain_cache(struct task_struct *curr,
+				  struct held_lock *hlock,
+				  u64 chain_key)
+{
+	struct hlist_head *hash_head = chainhashentry(chain_key);
+	struct lock_chain *chain;
+	int i, j;
+
+	/*
+	 * The caller must hold the graph lock, ensure we've got IRQs
+	 * disabled to make this an IRQ-safe lock.. for recursion reasons
+	 * lockdep won't complain about its own locking errors.
+	 */
+	if (lockdep_assert_locked())
+		return 0;
+
+	chain = alloc_lock_chain();
+	if (!chain) {
+		if (!debug_locks_off_graph_unlock())
+			return 0;
+
+		print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
+		dump_stack();
+		return 0;
+	}
+	chain->chain_key = chain_key;
+	chain->irq_context = hlock->irq_context;
+	i = get_first_held_lock(curr, hlock);
+	chain->depth = curr->lockdep_depth + 1 - i;
+
+	BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks));
+	BUILD_BUG_ON((1UL << 6)  <= ARRAY_SIZE(curr->held_locks));
+	BUILD_BUG_ON((1UL << 8*sizeof(chain_hlocks[0])) <= ARRAY_SIZE(lock_classes));
+
+	j = alloc_chain_hlocks(chain->depth);
+	if (j < 0) {
+		if (!debug_locks_off_graph_unlock())
+			return 0;
+
+		print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!");
+		dump_stack();
+		return 0;
+	}
+
+	chain->base = j;
+	for (j = 0; j < chain->depth - 1; j++, i++) {
+		int lock_id = hlock_id(curr->held_locks + i);
+
+		chain_hlocks[chain->base + j] = lock_id;
+	}
+	chain_hlocks[chain->base + j] = hlock_id(hlock);
+	hlist_add_head_rcu(&chain->entry, hash_head);
+	debug_atomic_inc(chain_lookup_misses);
+	inc_chains(chain->irq_context);
+
+	return 1;
+}
+
+/*
+ * Look up a dependency chain. Must be called with either the graph lock or
+ * the RCU read lock held.
+ */
+static inline struct lock_chain *lookup_chain_cache(u64 chain_key)
+{
+	struct hlist_head *hash_head = chainhashentry(chain_key);
+	struct lock_chain *chain;
+
+	hlist_for_each_entry_rcu(chain, hash_head, entry) {
+		if (READ_ONCE(chain->chain_key) == chain_key) {
+			debug_atomic_inc(chain_lookup_hits);
+			return chain;
+		}
+	}
+	return NULL;
+}
+
+/*
+ * If the key is not present yet in dependency chain cache then
+ * add it and return 1 - in this case the new dependency chain is
+ * validated. If the key is already hashed, return 0.
+ * (On return with 1 graph_lock is held.)
+ */
+static inline int lookup_chain_cache_add(struct task_struct *curr,
+					 struct held_lock *hlock,
+					 u64 chain_key)
+{
+	struct lock_class *class = hlock_class(hlock);
+	struct lock_chain *chain = lookup_chain_cache(chain_key);
+
+	if (chain) {
+cache_hit:
+		if (!check_no_collision(curr, hlock, chain))
+			return 0;
+
+		if (very_verbose(class)) {
+			printk("\nhash chain already cached, key: "
+					"%016Lx tail class: [%px] %s\n",
+					(unsigned long long)chain_key,
+					class->key, class->name);
+		}
+
+		return 0;
+	}
+
+	if (very_verbose(class)) {
+		printk("\nnew hash chain, key: %016Lx tail class: [%px] %s\n",
+			(unsigned long long)chain_key, class->key, class->name);
+	}
+
+	if (!graph_lock())
+		return 0;
+
+	/*
+	 * We have to walk the chain again locked - to avoid duplicates:
+	 */
+	chain = lookup_chain_cache(chain_key);
+	if (chain) {
+		graph_unlock();
+		goto cache_hit;
+	}
+
+	if (!add_chain_cache(curr, hlock, chain_key))
+		return 0;
+
+	return 1;
+}
+
+static int validate_chain(struct task_struct *curr,
+			  struct held_lock *hlock,
+			  int chain_head, u64 chain_key)
+{
+	/*
+	 * Trylock needs to maintain the stack of held locks, but it
+	 * does not add new dependencies, because trylock can be done
+	 * in any order.
+	 *
+	 * We look up the chain_key and do the O(N^2) check and update of
+	 * the dependencies only if this is a new dependency chain.
+	 * (If lookup_chain_cache_add() return with 1 it acquires
+	 * graph_lock for us)
+	 */
+	if (!hlock->trylock && hlock->check &&
+	    lookup_chain_cache_add(curr, hlock, chain_key)) {
+		/*
+		 * Check whether last held lock:
+		 *
+		 * - is irq-safe, if this lock is irq-unsafe
+		 * - is softirq-safe, if this lock is hardirq-unsafe
+		 *
+		 * And check whether the new lock's dependency graph
+		 * could lead back to the previous lock:
+		 *
+		 * - within the current held-lock stack
+		 * - across our accumulated lock dependency records
+		 *
+		 * any of these scenarios could lead to a deadlock.
+		 */
+		/*
+		 * The simple case: does the current hold the same lock
+		 * already?
+		 */
+		int ret = check_deadlock(curr, hlock);
+
+		if (!ret)
+			return 0;
+		/*
+		 * Add dependency only if this lock is not the head
+		 * of the chain, and if the new lock introduces no more
+		 * lock dependency (because we already hold a lock with the
+		 * same lock class) nor deadlock (because the nest_lock
+		 * serializes nesting locks), see the comments for
+		 * check_deadlock().
+		 */
+		if (!chain_head && ret != 2) {
+			if (!check_prevs_add(curr, hlock))
+				return 0;
+		}
+
+		graph_unlock();
+	} else {
+		/* after lookup_chain_cache_add(): */
+		if (unlikely(!debug_locks))
+			return 0;
+	}
+
+	return 1;
+}
+#else
+static inline int validate_chain(struct task_struct *curr,
+				 struct held_lock *hlock,
+				 int chain_head, u64 chain_key)
+{
+	return 1;
+}
+
+static void init_chain_block_buckets(void)	{ }
+#endif /* CONFIG_PROVE_LOCKING */
+
+/*
+ * We are building curr_chain_key incrementally, so double-check
+ * it from scratch, to make sure that it's done correctly:
+ */
+static void check_chain_key(struct task_struct *curr)
+{
+#ifdef CONFIG_DEBUG_LOCKDEP
+	struct held_lock *hlock, *prev_hlock = NULL;
+	unsigned int i;
+	u64 chain_key = INITIAL_CHAIN_KEY;
+
+	for (i = 0; i < curr->lockdep_depth; i++) {
+		hlock = curr->held_locks + i;
+		if (chain_key != hlock->prev_chain_key) {
+			debug_locks_off();
+			/*
+			 * We got mighty confused, our chain keys don't match
+			 * with what we expect, someone trample on our task state?
+			 */
+			WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n",
+				curr->lockdep_depth, i,
+				(unsigned long long)chain_key,
+				(unsigned long long)hlock->prev_chain_key);
+			return;
+		}
+
+		/*
+		 * hlock->class_idx can't go beyond MAX_LOCKDEP_KEYS, but is
+		 * it registered lock class index?
+		 */
+		if (DEBUG_LOCKS_WARN_ON(!test_bit(hlock->class_idx, lock_classes_in_use)))
+			return;
+
+		if (prev_hlock && (prev_hlock->irq_context !=
+							hlock->irq_context))
+			chain_key = INITIAL_CHAIN_KEY;
+		chain_key = iterate_chain_key(chain_key, hlock_id(hlock));
+		prev_hlock = hlock;
+	}
+	if (chain_key != curr->curr_chain_key) {
+		debug_locks_off();
+		/*
+		 * More smoking hash instead of calculating it, damn see these
+		 * numbers float.. I bet that a pink elephant stepped on my memory.
+		 */
+		WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n",
+			curr->lockdep_depth, i,
+			(unsigned long long)chain_key,
+			(unsigned long long)curr->curr_chain_key);
+	}
+#endif
+}
+
+#ifdef CONFIG_PROVE_LOCKING
+static int mark_lock(struct task_struct *curr, struct held_lock *this,
+		     enum lock_usage_bit new_bit);
+
+static void print_usage_bug_scenario(struct held_lock *lock)
+{
+	struct lock_class *class = hlock_class(lock);
+
+	printk(" Possible unsafe locking scenario:\n\n");
+	printk("       CPU0\n");
+	printk("       ----\n");
+	printk("  lock(");
+	__print_lock_name(class);
+	printk(KERN_CONT ");\n");
+	printk("  <Interrupt>\n");
+	printk("    lock(");
+	__print_lock_name(class);
+	printk(KERN_CONT ");\n");
+	printk("\n *** DEADLOCK ***\n\n");
+}
+
+static void
+print_usage_bug(struct task_struct *curr, struct held_lock *this,
+		enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
+{
+	if (!debug_locks_off() || debug_locks_silent)
+		return;
+
+	pr_warn("\n");
+	pr_warn("================================\n");
+	pr_warn("WARNING: inconsistent lock state\n");
+	print_kernel_ident();
+	pr_warn("--------------------------------\n");
+
+	pr_warn("inconsistent {%s} -> {%s} usage.\n",
+		usage_str[prev_bit], usage_str[new_bit]);
+
+	pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
+		curr->comm, task_pid_nr(curr),
+		lockdep_hardirq_context(), hardirq_count() >> HARDIRQ_SHIFT,
+		lockdep_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
+		lockdep_hardirqs_enabled(),
+		lockdep_softirqs_enabled(curr));
+	print_lock(this);
+
+	pr_warn("{%s} state was registered at:\n", usage_str[prev_bit]);
+	print_lock_trace(hlock_class(this)->usage_traces[prev_bit], 1);
+
+	print_irqtrace_events(curr);
+	pr_warn("\nother info that might help us debug this:\n");
+	print_usage_bug_scenario(this);
+
+	lockdep_print_held_locks(curr);
+
+	pr_warn("\nstack backtrace:\n");
+	dump_stack();
+}
+
+/*
+ * Print out an error if an invalid bit is set:
+ */
+static inline int
+valid_state(struct task_struct *curr, struct held_lock *this,
+	    enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
+{
+	if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) {
+		graph_unlock();
+		print_usage_bug(curr, this, bad_bit, new_bit);
+		return 0;
+	}
+	return 1;
+}
+
+
+/*
+ * print irq inversion bug:
+ */
+static void
+print_irq_inversion_bug(struct task_struct *curr,
+			struct lock_list *root, struct lock_list *other,
+			struct held_lock *this, int forwards,
+			const char *irqclass)
+{
+	struct lock_list *entry = other;
+	struct lock_list *middle = NULL;
+	int depth;
+
+	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+		return;
+
+	pr_warn("\n");
+	pr_warn("========================================================\n");
+	pr_warn("WARNING: possible irq lock inversion dependency detected\n");
+	print_kernel_ident();
+	pr_warn("--------------------------------------------------------\n");
+	pr_warn("%s/%d just changed the state of lock:\n",
+		curr->comm, task_pid_nr(curr));
+	print_lock(this);
+	if (forwards)
+		pr_warn("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
+	else
+		pr_warn("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
+	print_lock_name(other->class);
+	pr_warn("\n\nand interrupts could create inverse lock ordering between them.\n\n");
+
+	pr_warn("\nother info that might help us debug this:\n");
+
+	/* Find a middle lock (if one exists) */
+	depth = get_lock_depth(other);
+	do {
+		if (depth == 0 && (entry != root)) {
+			pr_warn("lockdep:%s bad path found in chain graph\n", __func__);
+			break;
+		}
+		middle = entry;
+		entry = get_lock_parent(entry);
+		depth--;
+	} while (entry && entry != root && (depth >= 0));
+	if (forwards)
+		print_irq_lock_scenario(root, other,
+			middle ? middle->class : root->class, other->class);
+	else
+		print_irq_lock_scenario(other, root,
+			middle ? middle->class : other->class, root->class);
+
+	lockdep_print_held_locks(curr);
+
+	pr_warn("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
+	root->trace = save_trace();
+	if (!root->trace)
+		return;
+	print_shortest_lock_dependencies(other, root);
+
+	pr_warn("\nstack backtrace:\n");
+	dump_stack();
+}
+
+/*
+ * Prove that in the forwards-direction subgraph starting at <this>
+ * there is no lock matching <mask>:
+ */
+static int
+check_usage_forwards(struct task_struct *curr, struct held_lock *this,
+		     enum lock_usage_bit bit)
+{
+	enum bfs_result ret;
+	struct lock_list root;
+	struct lock_list *target_entry;
+	enum lock_usage_bit read_bit = bit + LOCK_USAGE_READ_MASK;
+	unsigned usage_mask = lock_flag(bit) | lock_flag(read_bit);
+
+	bfs_init_root(&root, this);
+	ret = find_usage_forwards(&root, usage_mask, &target_entry);
+	if (bfs_error(ret)) {
+		print_bfs_bug(ret);
+		return 0;
+	}
+	if (ret == BFS_RNOMATCH)
+		return 1;
+
+	/* Check whether write or read usage is the match */
+	if (target_entry->class->usage_mask & lock_flag(bit)) {
+		print_irq_inversion_bug(curr, &root, target_entry,
+					this, 1, state_name(bit));
+	} else {
+		print_irq_inversion_bug(curr, &root, target_entry,
+					this, 1, state_name(read_bit));
+	}
+
+	return 0;
+}
+
+/*
+ * Prove that in the backwards-direction subgraph starting at <this>
+ * there is no lock matching <mask>:
+ */
+static int
+check_usage_backwards(struct task_struct *curr, struct held_lock *this,
+		      enum lock_usage_bit bit)
+{
+	enum bfs_result ret;
+	struct lock_list root;
+	struct lock_list *target_entry;
+	enum lock_usage_bit read_bit = bit + LOCK_USAGE_READ_MASK;
+	unsigned usage_mask = lock_flag(bit) | lock_flag(read_bit);
+
+	bfs_init_rootb(&root, this);
+	ret = find_usage_backwards(&root, usage_mask, &target_entry);
+	if (bfs_error(ret)) {
+		print_bfs_bug(ret);
+		return 0;
+	}
+	if (ret == BFS_RNOMATCH)
+		return 1;
+
+	/* Check whether write or read usage is the match */
+	if (target_entry->class->usage_mask & lock_flag(bit)) {
+		print_irq_inversion_bug(curr, &root, target_entry,
+					this, 0, state_name(bit));
+	} else {
+		print_irq_inversion_bug(curr, &root, target_entry,
+					this, 0, state_name(read_bit));
+	}
+
+	return 0;
+}
+
+void print_irqtrace_events(struct task_struct *curr)
+{
+	const struct irqtrace_events *trace = &curr->irqtrace;
+
+	printk("irq event stamp: %u\n", trace->irq_events);
+	printk("hardirqs last  enabled at (%u): [<%px>] %pS\n",
+		trace->hardirq_enable_event, (void *)trace->hardirq_enable_ip,
+		(void *)trace->hardirq_enable_ip);
+	printk("hardirqs last disabled at (%u): [<%px>] %pS\n",
+		trace->hardirq_disable_event, (void *)trace->hardirq_disable_ip,
+		(void *)trace->hardirq_disable_ip);
+	printk("softirqs last  enabled at (%u): [<%px>] %pS\n",
+		trace->softirq_enable_event, (void *)trace->softirq_enable_ip,
+		(void *)trace->softirq_enable_ip);
+	printk("softirqs last disabled at (%u): [<%px>] %pS\n",
+		trace->softirq_disable_event, (void *)trace->softirq_disable_ip,
+		(void *)trace->softirq_disable_ip);
+}
+
+static int HARDIRQ_verbose(struct lock_class *class)
+{
+#if HARDIRQ_VERBOSE
+	return class_filter(class);
+#endif
+	return 0;
+}
+
+static int SOFTIRQ_verbose(struct lock_class *class)
+{
+#if SOFTIRQ_VERBOSE
+	return class_filter(class);
+#endif
+	return 0;
+}
+
+static int (*state_verbose_f[])(struct lock_class *class) = {
+#define LOCKDEP_STATE(__STATE) \
+	__STATE##_verbose,
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static inline int state_verbose(enum lock_usage_bit bit,
+				struct lock_class *class)
+{
+	return state_verbose_f[bit >> LOCK_USAGE_DIR_MASK](class);
+}
+
+typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
+			     enum lock_usage_bit bit, const char *name);
+
+static int
+mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+		enum lock_usage_bit new_bit)
+{
+	int excl_bit = exclusive_bit(new_bit);
+	int read = new_bit & LOCK_USAGE_READ_MASK;
+	int dir = new_bit & LOCK_USAGE_DIR_MASK;
+
+	/*
+	 * Validate that this particular lock does not have conflicting
+	 * usage states.
+	 */
+	if (!valid_state(curr, this, new_bit, excl_bit))
+		return 0;
+
+	/*
+	 * Check for read in write conflicts
+	 */
+	if (!read && !valid_state(curr, this, new_bit,
+				  excl_bit + LOCK_USAGE_READ_MASK))
+		return 0;
+
+
+	/*
+	 * Validate that the lock dependencies don't have conflicting usage
+	 * states.
+	 */
+	if (dir) {
+		/*
+		 * mark ENABLED has to look backwards -- to ensure no dependee
+		 * has USED_IN state, which, again, would allow  recursion deadlocks.
+		 */
+		if (!check_usage_backwards(curr, this, excl_bit))
+			return 0;
+	} else {
+		/*
+		 * mark USED_IN has to look forwards -- to ensure no dependency
+		 * has ENABLED state, which would allow recursion deadlocks.
+		 */
+		if (!check_usage_forwards(curr, this, excl_bit))
+			return 0;
+	}
+
+	if (state_verbose(new_bit, hlock_class(this)))
+		return 2;
+
+	return 1;
+}
+
+/*
+ * Mark all held locks with a usage bit:
+ */
+static int
+mark_held_locks(struct task_struct *curr, enum lock_usage_bit base_bit)
+{
+	struct held_lock *hlock;
+	int i;
+
+	for (i = 0; i < curr->lockdep_depth; i++) {
+		enum lock_usage_bit hlock_bit = base_bit;
+		hlock = curr->held_locks + i;
+
+		if (hlock->read)
+			hlock_bit += LOCK_USAGE_READ_MASK;
+
+		BUG_ON(hlock_bit >= LOCK_USAGE_STATES);
+
+		if (!hlock->check)
+			continue;
+
+		if (!mark_lock(curr, hlock, hlock_bit))
+			return 0;
+	}
+
+	return 1;
+}
+
+/*
+ * Hardirqs will be enabled:
+ */
+static void __trace_hardirqs_on_caller(void)
+{
+	struct task_struct *curr = current;
+
+	/*
+	 * We are going to turn hardirqs on, so set the
+	 * usage bit for all held locks:
+	 */
+	if (!mark_held_locks(curr, LOCK_ENABLED_HARDIRQ))
+		return;
+	/*
+	 * If we have softirqs enabled, then set the usage
+	 * bit for all held locks. (disabled hardirqs prevented
+	 * this bit from being set before)
+	 */
+	if (curr->softirqs_enabled)
+		mark_held_locks(curr, LOCK_ENABLED_SOFTIRQ);
+}
+
+/**
+ * lockdep_hardirqs_on_prepare - Prepare for enabling interrupts
+ *
+ * Invoked before a possible transition to RCU idle from exit to user or
+ * guest mode. This ensures that all RCU operations are done before RCU
+ * stops watching. After the RCU transition lockdep_hardirqs_on() has to be
+ * invoked to set the final state.
+ */
+void lockdep_hardirqs_on_prepare(void)
+{
+	if (unlikely(!debug_locks))
+		return;
+
+	/*
+	 * NMIs do not (and cannot) track lock dependencies, nothing to do.
+	 */
+	if (unlikely(in_nmi()))
+		return;
+
+	if (unlikely(this_cpu_read(lockdep_recursion)))
+		return;
+
+	if (unlikely(lockdep_hardirqs_enabled())) {
+		/*
+		 * Neither irq nor preemption are disabled here
+		 * so this is racy by nature but losing one hit
+		 * in a stat is not a big deal.
+		 */
+		__debug_atomic_inc(redundant_hardirqs_on);
+		return;
+	}
+
+	/*
+	 * We're enabling irqs and according to our state above irqs weren't
+	 * already enabled, yet we find the hardware thinks they are in fact
+	 * enabled.. someone messed up their IRQ state tracing.
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return;
+
+	/*
+	 * See the fine text that goes along with this variable definition.
+	 */
+	if (DEBUG_LOCKS_WARN_ON(early_boot_irqs_disabled))
+		return;
+
+	/*
+	 * Can't allow enabling interrupts while in an interrupt handler,
+	 * that's general bad form and such. Recursion, limited stack etc..
+	 */
+	if (DEBUG_LOCKS_WARN_ON(lockdep_hardirq_context()))
+		return;
+
+	current->hardirq_chain_key = current->curr_chain_key;
+
+	lockdep_recursion_inc();
+	__trace_hardirqs_on_caller();
+	lockdep_recursion_finish();
+}
+EXPORT_SYMBOL_GPL(lockdep_hardirqs_on_prepare);
+
+void noinstr lockdep_hardirqs_on(unsigned long ip)
+{
+	struct irqtrace_events *trace = &current->irqtrace;
+
+	if (unlikely(!debug_locks))
+		return;
+
+	/*
+	 * NMIs can happen in the middle of local_irq_{en,dis}able() where the
+	 * tracking state and hardware state are out of sync.
+	 *
+	 * NMIs must save lockdep_hardirqs_enabled() to restore IRQ state from,
+	 * and not rely on hardware state like normal interrupts.
+	 */
+	if (unlikely(in_nmi())) {
+		if (!IS_ENABLED(CONFIG_TRACE_IRQFLAGS_NMI))
+			return;
+
+		/*
+		 * Skip:
+		 *  - recursion check, because NMI can hit lockdep;
+		 *  - hardware state check, because above;
+		 *  - chain_key check, see lockdep_hardirqs_on_prepare().
+		 */
+		goto skip_checks;
+	}
+
+	if (unlikely(this_cpu_read(lockdep_recursion)))
+		return;
+
+	if (lockdep_hardirqs_enabled()) {
+		/*
+		 * Neither irq nor preemption are disabled here
+		 * so this is racy by nature but losing one hit
+		 * in a stat is not a big deal.
+		 */
+		__debug_atomic_inc(redundant_hardirqs_on);
+		return;
+	}
+
+	/*
+	 * We're enabling irqs and according to our state above irqs weren't
+	 * already enabled, yet we find the hardware thinks they are in fact
+	 * enabled.. someone messed up their IRQ state tracing.
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return;
+
+	/*
+	 * Ensure the lock stack remained unchanged between
+	 * lockdep_hardirqs_on_prepare() and lockdep_hardirqs_on().
+	 */
+	DEBUG_LOCKS_WARN_ON(current->hardirq_chain_key !=
+			    current->curr_chain_key);
+
+skip_checks:
+	/* we'll do an OFF -> ON transition: */
+	__this_cpu_write(hardirqs_enabled, 1);
+	trace->hardirq_enable_ip = ip;
+	trace->hardirq_enable_event = ++trace->irq_events;
+	debug_atomic_inc(hardirqs_on_events);
+}
+EXPORT_SYMBOL_GPL(lockdep_hardirqs_on);
+
+/*
+ * Hardirqs were disabled:
+ */
+void noinstr lockdep_hardirqs_off(unsigned long ip)
+{
+	if (unlikely(!debug_locks))
+		return;
+
+	/*
+	 * Matching lockdep_hardirqs_on(), allow NMIs in the middle of lockdep;
+	 * they will restore the software state. This ensures the software
+	 * state is consistent inside NMIs as well.
+	 */
+	if (in_nmi()) {
+		if (!IS_ENABLED(CONFIG_TRACE_IRQFLAGS_NMI))
+			return;
+	} else if (__this_cpu_read(lockdep_recursion))
+		return;
+
+	/*
+	 * So we're supposed to get called after you mask local IRQs, but for
+	 * some reason the hardware doesn't quite think you did a proper job.
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return;
+
+	if (lockdep_hardirqs_enabled()) {
+		struct irqtrace_events *trace = &current->irqtrace;
+
+		/*
+		 * We have done an ON -> OFF transition:
+		 */
+		__this_cpu_write(hardirqs_enabled, 0);
+		trace->hardirq_disable_ip = ip;
+		trace->hardirq_disable_event = ++trace->irq_events;
+		debug_atomic_inc(hardirqs_off_events);
+	} else {
+		debug_atomic_inc(redundant_hardirqs_off);
+	}
+}
+EXPORT_SYMBOL_GPL(lockdep_hardirqs_off);
+
+/*
+ * Softirqs will be enabled:
+ */
+void lockdep_softirqs_on(unsigned long ip)
+{
+	struct irqtrace_events *trace = &current->irqtrace;
+
+	if (unlikely(!lockdep_enabled()))
+		return;
+
+	/*
+	 * We fancy IRQs being disabled here, see softirq.c, avoids
+	 * funny state and nesting things.
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return;
+
+	if (current->softirqs_enabled) {
+		debug_atomic_inc(redundant_softirqs_on);
+		return;
+	}
+
+	lockdep_recursion_inc();
+	/*
+	 * We'll do an OFF -> ON transition:
+	 */
+	current->softirqs_enabled = 1;
+	trace->softirq_enable_ip = ip;
+	trace->softirq_enable_event = ++trace->irq_events;
+	debug_atomic_inc(softirqs_on_events);
+	/*
+	 * We are going to turn softirqs on, so set the
+	 * usage bit for all held locks, if hardirqs are
+	 * enabled too:
+	 */
+	if (lockdep_hardirqs_enabled())
+		mark_held_locks(current, LOCK_ENABLED_SOFTIRQ);
+	lockdep_recursion_finish();
+}
+
+/*
+ * Softirqs were disabled:
+ */
+void lockdep_softirqs_off(unsigned long ip)
+{
+	if (unlikely(!lockdep_enabled()))
+		return;
+
+	/*
+	 * We fancy IRQs being disabled here, see softirq.c
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return;
+
+	if (current->softirqs_enabled) {
+		struct irqtrace_events *trace = &current->irqtrace;
+
+		/*
+		 * We have done an ON -> OFF transition:
+		 */
+		current->softirqs_enabled = 0;
+		trace->softirq_disable_ip = ip;
+		trace->softirq_disable_event = ++trace->irq_events;
+		debug_atomic_inc(softirqs_off_events);
+		/*
+		 * Whoops, we wanted softirqs off, so why aren't they?
+		 */
+		DEBUG_LOCKS_WARN_ON(!softirq_count());
+	} else
+		debug_atomic_inc(redundant_softirqs_off);
+}
+
+static int
+mark_usage(struct task_struct *curr, struct held_lock *hlock, int check)
+{
+	if (!check)
+		goto lock_used;
+
+	/*
+	 * If non-trylock use in a hardirq or softirq context, then
+	 * mark the lock as used in these contexts:
+	 */
+	if (!hlock->trylock) {
+		if (hlock->read) {
+			if (lockdep_hardirq_context())
+				if (!mark_lock(curr, hlock,
+						LOCK_USED_IN_HARDIRQ_READ))
+					return 0;
+			if (curr->softirq_context)
+				if (!mark_lock(curr, hlock,
+						LOCK_USED_IN_SOFTIRQ_READ))
+					return 0;
+		} else {
+			if (lockdep_hardirq_context())
+				if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
+					return 0;
+			if (curr->softirq_context)
+				if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
+					return 0;
+		}
+	}
+	if (!hlock->hardirqs_off) {
+		if (hlock->read) {
+			if (!mark_lock(curr, hlock,
+					LOCK_ENABLED_HARDIRQ_READ))
+				return 0;
+			if (curr->softirqs_enabled)
+				if (!mark_lock(curr, hlock,
+						LOCK_ENABLED_SOFTIRQ_READ))
+					return 0;
+		} else {
+			if (!mark_lock(curr, hlock,
+					LOCK_ENABLED_HARDIRQ))
+				return 0;
+			if (curr->softirqs_enabled)
+				if (!mark_lock(curr, hlock,
+						LOCK_ENABLED_SOFTIRQ))
+					return 0;
+		}
+	}
+
+lock_used:
+	/* mark it as used: */
+	if (!mark_lock(curr, hlock, LOCK_USED))
+		return 0;
+
+	return 1;
+}
+
+static inline unsigned int task_irq_context(struct task_struct *task)
+{
+	return LOCK_CHAIN_HARDIRQ_CONTEXT * !!lockdep_hardirq_context() +
+	       LOCK_CHAIN_SOFTIRQ_CONTEXT * !!task->softirq_context;
+}
+
+static int separate_irq_context(struct task_struct *curr,
+		struct held_lock *hlock)
+{
+	unsigned int depth = curr->lockdep_depth;
+
+	/*
+	 * Keep track of points where we cross into an interrupt context:
+	 */
+	if (depth) {
+		struct held_lock *prev_hlock;
+
+		prev_hlock = curr->held_locks + depth-1;
+		/*
+		 * If we cross into another context, reset the
+		 * hash key (this also prevents the checking and the
+		 * adding of the dependency to 'prev'):
+		 */
+		if (prev_hlock->irq_context != hlock->irq_context)
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * Mark a lock with a usage bit, and validate the state transition:
+ */
+static int mark_lock(struct task_struct *curr, struct held_lock *this,
+			     enum lock_usage_bit new_bit)
+{
+	unsigned int new_mask, ret = 1;
+
+	if (new_bit >= LOCK_USAGE_STATES) {
+		DEBUG_LOCKS_WARN_ON(1);
+		return 0;
+	}
+
+	if (new_bit == LOCK_USED && this->read)
+		new_bit = LOCK_USED_READ;
+
+	new_mask = 1 << new_bit;
+
+	/*
+	 * If already set then do not dirty the cacheline,
+	 * nor do any checks:
+	 */
+	if (likely(hlock_class(this)->usage_mask & new_mask))
+		return 1;
+
+	if (!graph_lock())
+		return 0;
+	/*
+	 * Make sure we didn't race:
+	 */
+	if (unlikely(hlock_class(this)->usage_mask & new_mask))
+		goto unlock;
+
+	if (!hlock_class(this)->usage_mask)
+		debug_atomic_dec(nr_unused_locks);
+
+	hlock_class(this)->usage_mask |= new_mask;
+
+	if (new_bit < LOCK_TRACE_STATES) {
+		if (!(hlock_class(this)->usage_traces[new_bit] = save_trace()))
+			return 0;
+	}
+
+	if (new_bit < LOCK_USED) {
+		ret = mark_lock_irq(curr, this, new_bit);
+		if (!ret)
+			return 0;
+	}
+
+unlock:
+	graph_unlock();
+
+	/*
+	 * We must printk outside of the graph_lock:
+	 */
+	if (ret == 2) {
+		printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
+		print_lock(this);
+		print_irqtrace_events(curr);
+		dump_stack();
+	}
+
+	return ret;
+}
+
+static inline short task_wait_context(struct task_struct *curr)
+{
+	/*
+	 * Set appropriate wait type for the context; for IRQs we have to take
+	 * into account force_irqthread as that is implied by PREEMPT_RT.
+	 */
+	if (lockdep_hardirq_context()) {
+		/*
+		 * Check if force_irqthreads will run us threaded.
+		 */
+		if (curr->hardirq_threaded || curr->irq_config)
+			return LD_WAIT_CONFIG;
+
+		return LD_WAIT_SPIN;
+	} else if (curr->softirq_context) {
+		/*
+		 * Softirqs are always threaded.
+		 */
+		return LD_WAIT_CONFIG;
+	}
+
+	return LD_WAIT_MAX;
+}
+
+static int
+print_lock_invalid_wait_context(struct task_struct *curr,
+				struct held_lock *hlock)
+{
+	short curr_inner;
+
+	if (!debug_locks_off())
+		return 0;
+	if (debug_locks_silent)
+		return 0;
+
+	pr_warn("\n");
+	pr_warn("=============================\n");
+	pr_warn("[ BUG: Invalid wait context ]\n");
+	print_kernel_ident();
+	pr_warn("-----------------------------\n");
+
+	pr_warn("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
+	print_lock(hlock);
+
+	pr_warn("other info that might help us debug this:\n");
+
+	curr_inner = task_wait_context(curr);
+	pr_warn("context-{%d:%d}\n", curr_inner, curr_inner);
+
+	lockdep_print_held_locks(curr);
+
+	pr_warn("stack backtrace:\n");
+	dump_stack();
+
+	return 0;
+}
+
+/*
+ * Verify the wait_type context.
+ *
+ * This check validates we take locks in the right wait-type order; that is it
+ * ensures that we do not take mutexes inside spinlocks and do not attempt to
+ * acquire spinlocks inside raw_spinlocks and the sort.
+ *
+ * The entire thing is slightly more complex because of RCU, RCU is a lock that
+ * can be taken from (pretty much) any context but also has constraints.
+ * However when taken in a stricter environment the RCU lock does not loosen
+ * the constraints.
+ *
+ * Therefore we must look for the strictest environment in the lock stack and
+ * compare that to the lock we're trying to acquire.
+ */
+static int check_wait_context(struct task_struct *curr, struct held_lock *next)
+{
+	u8 next_inner = hlock_class(next)->wait_type_inner;
+	u8 next_outer = hlock_class(next)->wait_type_outer;
+	u8 curr_inner;
+	int depth;
+
+	if (!next_inner || next->trylock)
+		return 0;
+
+	if (!next_outer)
+		next_outer = next_inner;
+
+	/*
+	 * Find start of current irq_context..
+	 */
+	for (depth = curr->lockdep_depth - 1; depth >= 0; depth--) {
+		struct held_lock *prev = curr->held_locks + depth;
+		if (prev->irq_context != next->irq_context)
+			break;
+	}
+	depth++;
+
+	curr_inner = task_wait_context(curr);
+
+	for (; depth < curr->lockdep_depth; depth++) {
+		struct held_lock *prev = curr->held_locks + depth;
+		u8 prev_inner = hlock_class(prev)->wait_type_inner;
+
+		if (prev_inner) {
+			/*
+			 * We can have a bigger inner than a previous one
+			 * when outer is smaller than inner, as with RCU.
+			 *
+			 * Also due to trylocks.
+			 */
+			curr_inner = min(curr_inner, prev_inner);
+		}
+	}
+
+	if (next_outer > curr_inner)
+		return print_lock_invalid_wait_context(curr, next);
+
+	return 0;
+}
+
+#else /* CONFIG_PROVE_LOCKING */
+
+static inline int
+mark_usage(struct task_struct *curr, struct held_lock *hlock, int check)
+{
+	return 1;
+}
+
+static inline unsigned int task_irq_context(struct task_struct *task)
+{
+	return 0;
+}
+
+static inline int separate_irq_context(struct task_struct *curr,
+		struct held_lock *hlock)
+{
+	return 0;
+}
+
+static inline int check_wait_context(struct task_struct *curr,
+				     struct held_lock *next)
+{
+	return 0;
+}
+
+#endif /* CONFIG_PROVE_LOCKING */
+
+/*
+ * Initialize a lock instance's lock-class mapping info:
+ */
+void lockdep_init_map_type(struct lockdep_map *lock, const char *name,
+			    struct lock_class_key *key, int subclass,
+			    u8 inner, u8 outer, u8 lock_type)
+{
+	int i;
+
+	for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
+		lock->class_cache[i] = NULL;
+
+#ifdef CONFIG_LOCK_STAT
+	lock->cpu = raw_smp_processor_id();
+#endif
+
+	/*
+	 * Can't be having no nameless bastards around this place!
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!name)) {
+		lock->name = "NULL";
+		return;
+	}
+
+	lock->name = name;
+
+	lock->wait_type_outer = outer;
+	lock->wait_type_inner = inner;
+	lock->lock_type = lock_type;
+
+	/*
+	 * No key, no joy, we need to hash something.
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!key))
+		return;
+	/*
+	 * Sanity check, the lock-class key must either have been allocated
+	 * statically or must have been registered as a dynamic key.
+	 */
+	if (!static_obj(key) && !is_dynamic_key(key)) {
+		if (debug_locks)
+			printk(KERN_ERR "BUG: key %px has not been registered!\n", key);
+		DEBUG_LOCKS_WARN_ON(1);
+		return;
+	}
+	lock->key = key;
+
+	if (unlikely(!debug_locks))
+		return;
+
+	if (subclass) {
+		unsigned long flags;
+
+		if (DEBUG_LOCKS_WARN_ON(!lockdep_enabled()))
+			return;
+
+		raw_local_irq_save(flags);
+		lockdep_recursion_inc();
+		register_lock_class(lock, subclass, 1);
+		lockdep_recursion_finish();
+		raw_local_irq_restore(flags);
+	}
+}
+EXPORT_SYMBOL_GPL(lockdep_init_map_type);
+
+struct lock_class_key __lockdep_no_validate__;
+EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
+
+static void
+print_lock_nested_lock_not_held(struct task_struct *curr,
+				struct held_lock *hlock)
+{
+	if (!debug_locks_off())
+		return;
+	if (debug_locks_silent)
+		return;
+
+	pr_warn("\n");
+	pr_warn("==================================\n");
+	pr_warn("WARNING: Nested lock was not taken\n");
+	print_kernel_ident();
+	pr_warn("----------------------------------\n");
+
+	pr_warn("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
+	print_lock(hlock);
+
+	pr_warn("\nbut this task is not holding:\n");
+	pr_warn("%s\n", hlock->nest_lock->name);
+
+	pr_warn("\nstack backtrace:\n");
+	dump_stack();
+
+	pr_warn("\nother info that might help us debug this:\n");
+	lockdep_print_held_locks(curr);
+
+	pr_warn("\nstack backtrace:\n");
+	dump_stack();
+}
+
+static int __lock_is_held(const struct lockdep_map *lock, int read);
+
+/*
+ * This gets called for every mutex_lock*()/spin_lock*() operation.
+ * We maintain the dependency maps and validate the locking attempt:
+ *
+ * The callers must make sure that IRQs are disabled before calling it,
+ * otherwise we could get an interrupt which would want to take locks,
+ * which would end up in lockdep again.
+ */
+static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
+			  int trylock, int read, int check, int hardirqs_off,
+			  struct lockdep_map *nest_lock, unsigned long ip,
+			  int references, int pin_count)
+{
+	struct task_struct *curr = current;
+	struct lock_class *class = NULL;
+	struct held_lock *hlock;
+	unsigned int depth;
+	int chain_head = 0;
+	int class_idx;
+	u64 chain_key;
+
+	if (unlikely(!debug_locks))
+		return 0;
+
+	if (!prove_locking || lock->key == &__lockdep_no_validate__)
+		check = 0;
+
+	if (subclass < NR_LOCKDEP_CACHING_CLASSES)
+		class = lock->class_cache[subclass];
+	/*
+	 * Not cached?
+	 */
+	if (unlikely(!class)) {
+		class = register_lock_class(lock, subclass, 0);
+		if (!class)
+			return 0;
+	}
+
+	debug_class_ops_inc(class);
+
+	if (very_verbose(class)) {
+		printk("\nacquire class [%px] %s", class->key, class->name);
+		if (class->name_version > 1)
+			printk(KERN_CONT "#%d", class->name_version);
+		printk(KERN_CONT "\n");
+		dump_stack();
+	}
+
+	/*
+	 * Add the lock to the list of currently held locks.
+	 * (we dont increase the depth just yet, up until the
+	 * dependency checks are done)
+	 */
+	depth = curr->lockdep_depth;
+	/*
+	 * Ran out of static storage for our per-task lock stack again have we?
+	 */
+	if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
+		return 0;
+
+	class_idx = class - lock_classes;
+
+	if (depth) { /* we're holding locks */
+		hlock = curr->held_locks + depth - 1;
+		if (hlock->class_idx == class_idx && nest_lock) {
+			if (!references)
+				references++;
+
+			if (!hlock->references)
+				hlock->references++;
+
+			hlock->references += references;
+
+			/* Overflow */
+			if (DEBUG_LOCKS_WARN_ON(hlock->references < references))
+				return 0;
+
+			return 2;
+		}
+	}
+
+	hlock = curr->held_locks + depth;
+	/*
+	 * Plain impossible, we just registered it and checked it weren't no
+	 * NULL like.. I bet this mushroom I ate was good!
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!class))
+		return 0;
+	hlock->class_idx = class_idx;
+	hlock->acquire_ip = ip;
+	hlock->instance = lock;
+	hlock->nest_lock = nest_lock;
+	hlock->irq_context = task_irq_context(curr);
+	hlock->trylock = trylock;
+	hlock->read = read;
+	hlock->check = check;
+	hlock->hardirqs_off = !!hardirqs_off;
+	hlock->references = references;
+#ifdef CONFIG_LOCK_STAT
+	hlock->waittime_stamp = 0;
+	hlock->holdtime_stamp = lockstat_clock();
+#endif
+	hlock->pin_count = pin_count;
+
+	if (check_wait_context(curr, hlock))
+		return 0;
+
+	/* Initialize the lock usage bit */
+	if (!mark_usage(curr, hlock, check))
+		return 0;
+
+	/*
+	 * Calculate the chain hash: it's the combined hash of all the
+	 * lock keys along the dependency chain. We save the hash value
+	 * at every step so that we can get the current hash easily
+	 * after unlock. The chain hash is then used to cache dependency
+	 * results.
+	 *
+	 * The 'key ID' is what is the most compact key value to drive
+	 * the hash, not class->key.
+	 */
+	/*
+	 * Whoops, we did it again.. class_idx is invalid.
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!test_bit(class_idx, lock_classes_in_use)))
+		return 0;
+
+	chain_key = curr->curr_chain_key;
+	if (!depth) {
+		/*
+		 * How can we have a chain hash when we ain't got no keys?!
+		 */
+		if (DEBUG_LOCKS_WARN_ON(chain_key != INITIAL_CHAIN_KEY))
+			return 0;
+		chain_head = 1;
+	}
+
+	hlock->prev_chain_key = chain_key;
+	if (separate_irq_context(curr, hlock)) {
+		chain_key = INITIAL_CHAIN_KEY;
+		chain_head = 1;
+	}
+	chain_key = iterate_chain_key(chain_key, hlock_id(hlock));
+
+	if (nest_lock && !__lock_is_held(nest_lock, -1)) {
+		print_lock_nested_lock_not_held(curr, hlock);
+		return 0;
+	}
+
+	if (!debug_locks_silent) {
+		WARN_ON_ONCE(depth && !hlock_class(hlock - 1)->key);
+		WARN_ON_ONCE(!hlock_class(hlock)->key);
+	}
+
+	if (!validate_chain(curr, hlock, chain_head, chain_key))
+		return 0;
+
+	curr->curr_chain_key = chain_key;
+	curr->lockdep_depth++;
+	check_chain_key(curr);
+#ifdef CONFIG_DEBUG_LOCKDEP
+	if (unlikely(!debug_locks))
+		return 0;
+#endif
+	if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
+		debug_locks_off();
+		print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!");
+		printk(KERN_DEBUG "depth: %i  max: %lu!\n",
+		       curr->lockdep_depth, MAX_LOCK_DEPTH);
+
+		lockdep_print_held_locks(current);
+		debug_show_all_locks();
+		dump_stack();
+
+		return 0;
+	}
+
+	if (unlikely(curr->lockdep_depth > max_lockdep_depth))
+		max_lockdep_depth = curr->lockdep_depth;
+
+	return 1;
+}
+
+static void print_unlock_imbalance_bug(struct task_struct *curr,
+				       struct lockdep_map *lock,
+				       unsigned long ip)
+{
+	if (!debug_locks_off())
+		return;
+	if (debug_locks_silent)
+		return;
+
+	pr_warn("\n");
+	pr_warn("=====================================\n");
+	pr_warn("WARNING: bad unlock balance detected!\n");
+	print_kernel_ident();
+	pr_warn("-------------------------------------\n");
+	pr_warn("%s/%d is trying to release lock (",
+		curr->comm, task_pid_nr(curr));
+	print_lockdep_cache(lock);
+	pr_cont(") at:\n");
+	print_ip_sym(KERN_WARNING, ip);
+	pr_warn("but there are no more locks to release!\n");
+	pr_warn("\nother info that might help us debug this:\n");
+	lockdep_print_held_locks(curr);
+
+	pr_warn("\nstack backtrace:\n");
+	dump_stack();
+}
+
+static noinstr int match_held_lock(const struct held_lock *hlock,
+				   const struct lockdep_map *lock)
+{
+	if (hlock->instance == lock)
+		return 1;
+
+	if (hlock->references) {
+		const struct lock_class *class = lock->class_cache[0];
+
+		if (!class)
+			class = look_up_lock_class(lock, 0);
+
+		/*
+		 * If look_up_lock_class() failed to find a class, we're trying
+		 * to test if we hold a lock that has never yet been acquired.
+		 * Clearly if the lock hasn't been acquired _ever_, we're not
+		 * holding it either, so report failure.
+		 */
+		if (!class)
+			return 0;
+
+		/*
+		 * References, but not a lock we're actually ref-counting?
+		 * State got messed up, follow the sites that change ->references
+		 * and try to make sense of it.
+		 */
+		if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock))
+			return 0;
+
+		if (hlock->class_idx == class - lock_classes)
+			return 1;
+	}
+
+	return 0;
+}
+
+/* @depth must not be zero */
+static struct held_lock *find_held_lock(struct task_struct *curr,
+					struct lockdep_map *lock,
+					unsigned int depth, int *idx)
+{
+	struct held_lock *ret, *hlock, *prev_hlock;
+	int i;
+
+	i = depth - 1;
+	hlock = curr->held_locks + i;
+	ret = hlock;
+	if (match_held_lock(hlock, lock))
+		goto out;
+
+	ret = NULL;
+	for (i--, prev_hlock = hlock--;
+	     i >= 0;
+	     i--, prev_hlock = hlock--) {
+		/*
+		 * We must not cross into another context:
+		 */
+		if (prev_hlock->irq_context != hlock->irq_context) {
+			ret = NULL;
+			break;
+		}
+		if (match_held_lock(hlock, lock)) {
+			ret = hlock;
+			break;
+		}
+	}
+
+out:
+	*idx = i;
+	return ret;
+}
+
+static int reacquire_held_locks(struct task_struct *curr, unsigned int depth,
+				int idx, unsigned int *merged)
+{
+	struct held_lock *hlock;
+	int first_idx = idx;
+
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return 0;
+
+	for (hlock = curr->held_locks + idx; idx < depth; idx++, hlock++) {
+		switch (__lock_acquire(hlock->instance,
+				    hlock_class(hlock)->subclass,
+				    hlock->trylock,
+				    hlock->read, hlock->check,
+				    hlock->hardirqs_off,
+				    hlock->nest_lock, hlock->acquire_ip,
+				    hlock->references, hlock->pin_count)) {
+		case 0:
+			return 1;
+		case 1:
+			break;
+		case 2:
+			*merged += (idx == first_idx);
+			break;
+		default:
+			WARN_ON(1);
+			return 0;
+		}
+	}
+	return 0;
+}
+
+static int
+__lock_set_class(struct lockdep_map *lock, const char *name,
+		 struct lock_class_key *key, unsigned int subclass,
+		 unsigned long ip)
+{
+	struct task_struct *curr = current;
+	unsigned int depth, merged = 0;
+	struct held_lock *hlock;
+	struct lock_class *class;
+	int i;
+
+	if (unlikely(!debug_locks))
+		return 0;
+
+	depth = curr->lockdep_depth;
+	/*
+	 * This function is about (re)setting the class of a held lock,
+	 * yet we're not actually holding any locks. Naughty user!
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!depth))
+		return 0;
+
+	hlock = find_held_lock(curr, lock, depth, &i);
+	if (!hlock) {
+		print_unlock_imbalance_bug(curr, lock, ip);
+		return 0;
+	}
+
+	lockdep_init_map_type(lock, name, key, 0,
+			      lock->wait_type_inner,
+			      lock->wait_type_outer,
+			      lock->lock_type);
+	class = register_lock_class(lock, subclass, 0);
+	hlock->class_idx = class - lock_classes;
+
+	curr->lockdep_depth = i;
+	curr->curr_chain_key = hlock->prev_chain_key;
+
+	if (reacquire_held_locks(curr, depth, i, &merged))
+		return 0;
+
+	/*
+	 * I took it apart and put it back together again, except now I have
+	 * these 'spare' parts.. where shall I put them.
+	 */
+	if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - merged))
+		return 0;
+	return 1;
+}
+
+static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip)
+{
+	struct task_struct *curr = current;
+	unsigned int depth, merged = 0;
+	struct held_lock *hlock;
+	int i;
+
+	if (unlikely(!debug_locks))
+		return 0;
+
+	depth = curr->lockdep_depth;
+	/*
+	 * This function is about (re)setting the class of a held lock,
+	 * yet we're not actually holding any locks. Naughty user!
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!depth))
+		return 0;
+
+	hlock = find_held_lock(curr, lock, depth, &i);
+	if (!hlock) {
+		print_unlock_imbalance_bug(curr, lock, ip);
+		return 0;
+	}
+
+	curr->lockdep_depth = i;
+	curr->curr_chain_key = hlock->prev_chain_key;
+
+	WARN(hlock->read, "downgrading a read lock");
+	hlock->read = 1;
+	hlock->acquire_ip = ip;
+
+	if (reacquire_held_locks(curr, depth, i, &merged))
+		return 0;
+
+	/* Merging can't happen with unchanged classes.. */
+	if (DEBUG_LOCKS_WARN_ON(merged))
+		return 0;
+
+	/*
+	 * I took it apart and put it back together again, except now I have
+	 * these 'spare' parts.. where shall I put them.
+	 */
+	if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
+		return 0;
+
+	return 1;
+}
+
+/*
+ * Remove the lock from the list of currently held locks - this gets
+ * called on mutex_unlock()/spin_unlock*() (or on a failed
+ * mutex_lock_interruptible()).
+ */
+static int
+__lock_release(struct lockdep_map *lock, unsigned long ip)
+{
+	struct task_struct *curr = current;
+	unsigned int depth, merged = 1;
+	struct held_lock *hlock;
+	int i;
+
+	if (unlikely(!debug_locks))
+		return 0;
+
+	depth = curr->lockdep_depth;
+	/*
+	 * So we're all set to release this lock.. wait what lock? We don't
+	 * own any locks, you've been drinking again?
+	 */
+	if (depth <= 0) {
+		print_unlock_imbalance_bug(curr, lock, ip);
+		return 0;
+	}
+
+	/*
+	 * Check whether the lock exists in the current stack
+	 * of held locks:
+	 */
+	hlock = find_held_lock(curr, lock, depth, &i);
+	if (!hlock) {
+		print_unlock_imbalance_bug(curr, lock, ip);
+		return 0;
+	}
+
+	if (hlock->instance == lock)
+		lock_release_holdtime(hlock);
+
+	WARN(hlock->pin_count, "releasing a pinned lock\n");
+
+	if (hlock->references) {
+		hlock->references--;
+		if (hlock->references) {
+			/*
+			 * We had, and after removing one, still have
+			 * references, the current lock stack is still
+			 * valid. We're done!
+			 */
+			return 1;
+		}
+	}
+
+	/*
+	 * We have the right lock to unlock, 'hlock' points to it.
+	 * Now we remove it from the stack, and add back the other
+	 * entries (if any), recalculating the hash along the way:
+	 */
+
+	curr->lockdep_depth = i;
+	curr->curr_chain_key = hlock->prev_chain_key;
+
+	/*
+	 * The most likely case is when the unlock is on the innermost
+	 * lock. In this case, we are done!
+	 */
+	if (i == depth-1)
+		return 1;
+
+	if (reacquire_held_locks(curr, depth, i + 1, &merged))
+		return 0;
+
+	/*
+	 * We had N bottles of beer on the wall, we drank one, but now
+	 * there's not N-1 bottles of beer left on the wall...
+	 * Pouring two of the bottles together is acceptable.
+	 */
+	DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - merged);
+
+	/*
+	 * Since reacquire_held_locks() would have called check_chain_key()
+	 * indirectly via __lock_acquire(), we don't need to do it again
+	 * on return.
+	 */
+	return 0;
+}
+
+static __always_inline
+int __lock_is_held(const struct lockdep_map *lock, int read)
+{
+	struct task_struct *curr = current;
+	int i;
+
+	for (i = 0; i < curr->lockdep_depth; i++) {
+		struct held_lock *hlock = curr->held_locks + i;
+
+		if (match_held_lock(hlock, lock)) {
+			if (read == -1 || !!hlock->read == read)
+				return LOCK_STATE_HELD;
+
+			return LOCK_STATE_NOT_HELD;
+		}
+	}
+
+	return LOCK_STATE_NOT_HELD;
+}
+
+static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock)
+{
+	struct pin_cookie cookie = NIL_COOKIE;
+	struct task_struct *curr = current;
+	int i;
+
+	if (unlikely(!debug_locks))
+		return cookie;
+
+	for (i = 0; i < curr->lockdep_depth; i++) {
+		struct held_lock *hlock = curr->held_locks + i;
+
+		if (match_held_lock(hlock, lock)) {
+			/*
+			 * Grab 16bits of randomness; this is sufficient to not
+			 * be guessable and still allows some pin nesting in
+			 * our u32 pin_count.
+			 */
+			cookie.val = 1 + (sched_clock() & 0xffff);
+			hlock->pin_count += cookie.val;
+			return cookie;
+		}
+	}
+
+	WARN(1, "pinning an unheld lock\n");
+	return cookie;
+}
+
+static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
+{
+	struct task_struct *curr = current;
+	int i;
+
+	if (unlikely(!debug_locks))
+		return;
+
+	for (i = 0; i < curr->lockdep_depth; i++) {
+		struct held_lock *hlock = curr->held_locks + i;
+
+		if (match_held_lock(hlock, lock)) {
+			hlock->pin_count += cookie.val;
+			return;
+		}
+	}
+
+	WARN(1, "pinning an unheld lock\n");
+}
+
+static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
+{
+	struct task_struct *curr = current;
+	int i;
+
+	if (unlikely(!debug_locks))
+		return;
+
+	for (i = 0; i < curr->lockdep_depth; i++) {
+		struct held_lock *hlock = curr->held_locks + i;
+
+		if (match_held_lock(hlock, lock)) {
+			if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n"))
+				return;
+
+			hlock->pin_count -= cookie.val;
+
+			if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n"))
+				hlock->pin_count = 0;
+
+			return;
+		}
+	}
+
+	WARN(1, "unpinning an unheld lock\n");
+}
+
+/*
+ * Check whether we follow the irq-flags state precisely:
+ */
+static noinstr void check_flags(unsigned long flags)
+{
+#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP)
+	if (!debug_locks)
+		return;
+
+	/* Get the warning out..  */
+	instrumentation_begin();
+
+	if (irqs_disabled_flags(flags)) {
+		if (DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled())) {
+			printk("possible reason: unannotated irqs-off.\n");
+		}
+	} else {
+		if (DEBUG_LOCKS_WARN_ON(!lockdep_hardirqs_enabled())) {
+			printk("possible reason: unannotated irqs-on.\n");
+		}
+	}
+
+#ifndef CONFIG_PREEMPT_RT
+	/*
+	 * We dont accurately track softirq state in e.g.
+	 * hardirq contexts (such as on 4KSTACKS), so only
+	 * check if not in hardirq contexts:
+	 */
+	if (!hardirq_count()) {
+		if (softirq_count()) {
+			/* like the above, but with softirqs */
+			DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
+		} else {
+			/* lick the above, does it taste good? */
+			DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
+		}
+	}
+#endif
+
+	if (!debug_locks)
+		print_irqtrace_events(current);
+
+	instrumentation_end();
+#endif
+}
+
+void lock_set_class(struct lockdep_map *lock, const char *name,
+		    struct lock_class_key *key, unsigned int subclass,
+		    unsigned long ip)
+{
+	unsigned long flags;
+
+	if (unlikely(!lockdep_enabled()))
+		return;
+
+	raw_local_irq_save(flags);
+	lockdep_recursion_inc();
+	check_flags(flags);
+	if (__lock_set_class(lock, name, key, subclass, ip))
+		check_chain_key(current);
+	lockdep_recursion_finish();
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_set_class);
+
+void lock_downgrade(struct lockdep_map *lock, unsigned long ip)
+{
+	unsigned long flags;
+
+	if (unlikely(!lockdep_enabled()))
+		return;
+
+	raw_local_irq_save(flags);
+	lockdep_recursion_inc();
+	check_flags(flags);
+	if (__lock_downgrade(lock, ip))
+		check_chain_key(current);
+	lockdep_recursion_finish();
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_downgrade);
+
+/* NMI context !!! */
+static void verify_lock_unused(struct lockdep_map *lock, struct held_lock *hlock, int subclass)
+{
+#ifdef CONFIG_PROVE_LOCKING
+	struct lock_class *class = look_up_lock_class(lock, subclass);
+	unsigned long mask = LOCKF_USED;
+
+	/* if it doesn't have a class (yet), it certainly hasn't been used yet */
+	if (!class)
+		return;
+
+	/*
+	 * READ locks only conflict with USED, such that if we only ever use
+	 * READ locks, there is no deadlock possible -- RCU.
+	 */
+	if (!hlock->read)
+		mask |= LOCKF_USED_READ;
+
+	if (!(class->usage_mask & mask))
+		return;
+
+	hlock->class_idx = class - lock_classes;
+
+	print_usage_bug(current, hlock, LOCK_USED, LOCK_USAGE_STATES);
+#endif
+}
+
+static bool lockdep_nmi(void)
+{
+	if (raw_cpu_read(lockdep_recursion))
+		return false;
+
+	if (!in_nmi())
+		return false;
+
+	return true;
+}
+
+/*
+ * read_lock() is recursive if:
+ * 1. We force lockdep think this way in selftests or
+ * 2. The implementation is not queued read/write lock or
+ * 3. The locker is at an in_interrupt() context.
+ */
+bool read_lock_is_recursive(void)
+{
+	return force_read_lock_recursive ||
+	       !IS_ENABLED(CONFIG_QUEUED_RWLOCKS) ||
+	       in_interrupt();
+}
+EXPORT_SYMBOL_GPL(read_lock_is_recursive);
+
+/*
+ * We are not always called with irqs disabled - do that here,
+ * and also avoid lockdep recursion:
+ */
+void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
+			  int trylock, int read, int check,
+			  struct lockdep_map *nest_lock, unsigned long ip)
+{
+	unsigned long flags;
+
+	trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
+
+	if (!debug_locks)
+		return;
+
+	if (unlikely(!lockdep_enabled())) {
+		/* XXX allow trylock from NMI ?!? */
+		if (lockdep_nmi() && !trylock) {
+			struct held_lock hlock;
+
+			hlock.acquire_ip = ip;
+			hlock.instance = lock;
+			hlock.nest_lock = nest_lock;
+			hlock.irq_context = 2; // XXX
+			hlock.trylock = trylock;
+			hlock.read = read;
+			hlock.check = check;
+			hlock.hardirqs_off = true;
+			hlock.references = 0;
+
+			verify_lock_unused(lock, &hlock, subclass);
+		}
+		return;
+	}
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+
+	lockdep_recursion_inc();
+	__lock_acquire(lock, subclass, trylock, read, check,
+		       irqs_disabled_flags(flags), nest_lock, ip, 0, 0);
+	lockdep_recursion_finish();
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_acquire);
+
+void lock_release(struct lockdep_map *lock, unsigned long ip)
+{
+	unsigned long flags;
+
+	trace_lock_release(lock, ip);
+
+	if (unlikely(!lockdep_enabled()))
+		return;
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+
+	lockdep_recursion_inc();
+	if (__lock_release(lock, ip))
+		check_chain_key(current);
+	lockdep_recursion_finish();
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_release);
+
+noinstr int lock_is_held_type(const struct lockdep_map *lock, int read)
+{
+	unsigned long flags;
+	int ret = LOCK_STATE_NOT_HELD;
+
+	/*
+	 * Avoid false negative lockdep_assert_held() and
+	 * lockdep_assert_not_held().
+	 */
+	if (unlikely(!lockdep_enabled()))
+		return LOCK_STATE_UNKNOWN;
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+
+	lockdep_recursion_inc();
+	ret = __lock_is_held(lock, read);
+	lockdep_recursion_finish();
+	raw_local_irq_restore(flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(lock_is_held_type);
+NOKPROBE_SYMBOL(lock_is_held_type);
+
+struct pin_cookie lock_pin_lock(struct lockdep_map *lock)
+{
+	struct pin_cookie cookie = NIL_COOKIE;
+	unsigned long flags;
+
+	if (unlikely(!lockdep_enabled()))
+		return cookie;
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+
+	lockdep_recursion_inc();
+	cookie = __lock_pin_lock(lock);
+	lockdep_recursion_finish();
+	raw_local_irq_restore(flags);
+
+	return cookie;
+}
+EXPORT_SYMBOL_GPL(lock_pin_lock);
+
+void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
+{
+	unsigned long flags;
+
+	if (unlikely(!lockdep_enabled()))
+		return;
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+
+	lockdep_recursion_inc();
+	__lock_repin_lock(lock, cookie);
+	lockdep_recursion_finish();
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_repin_lock);
+
+void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
+{
+	unsigned long flags;
+
+	if (unlikely(!lockdep_enabled()))
+		return;
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+
+	lockdep_recursion_inc();
+	__lock_unpin_lock(lock, cookie);
+	lockdep_recursion_finish();
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_unpin_lock);
+
+#ifdef CONFIG_LOCK_STAT
+static void print_lock_contention_bug(struct task_struct *curr,
+				      struct lockdep_map *lock,
+				      unsigned long ip)
+{
+	if (!debug_locks_off())
+		return;
+	if (debug_locks_silent)
+		return;
+
+	pr_warn("\n");
+	pr_warn("=================================\n");
+	pr_warn("WARNING: bad contention detected!\n");
+	print_kernel_ident();
+	pr_warn("---------------------------------\n");
+	pr_warn("%s/%d is trying to contend lock (",
+		curr->comm, task_pid_nr(curr));
+	print_lockdep_cache(lock);
+	pr_cont(") at:\n");
+	print_ip_sym(KERN_WARNING, ip);
+	pr_warn("but there are no locks held!\n");
+	pr_warn("\nother info that might help us debug this:\n");
+	lockdep_print_held_locks(curr);
+
+	pr_warn("\nstack backtrace:\n");
+	dump_stack();
+}
+
+static void
+__lock_contended(struct lockdep_map *lock, unsigned long ip)
+{
+	struct task_struct *curr = current;
+	struct held_lock *hlock;
+	struct lock_class_stats *stats;
+	unsigned int depth;
+	int i, contention_point, contending_point;
+
+	depth = curr->lockdep_depth;
+	/*
+	 * Whee, we contended on this lock, except it seems we're not
+	 * actually trying to acquire anything much at all..
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!depth))
+		return;
+
+	hlock = find_held_lock(curr, lock, depth, &i);
+	if (!hlock) {
+		print_lock_contention_bug(curr, lock, ip);
+		return;
+	}
+
+	if (hlock->instance != lock)
+		return;
+
+	hlock->waittime_stamp = lockstat_clock();
+
+	contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
+	contending_point = lock_point(hlock_class(hlock)->contending_point,
+				      lock->ip);
+
+	stats = get_lock_stats(hlock_class(hlock));
+	if (contention_point < LOCKSTAT_POINTS)
+		stats->contention_point[contention_point]++;
+	if (contending_point < LOCKSTAT_POINTS)
+		stats->contending_point[contending_point]++;
+	if (lock->cpu != smp_processor_id())
+		stats->bounces[bounce_contended + !!hlock->read]++;
+}
+
+static void
+__lock_acquired(struct lockdep_map *lock, unsigned long ip)
+{
+	struct task_struct *curr = current;
+	struct held_lock *hlock;
+	struct lock_class_stats *stats;
+	unsigned int depth;
+	u64 now, waittime = 0;
+	int i, cpu;
+
+	depth = curr->lockdep_depth;
+	/*
+	 * Yay, we acquired ownership of this lock we didn't try to
+	 * acquire, how the heck did that happen?
+	 */
+	if (DEBUG_LOCKS_WARN_ON(!depth))
+		return;
+
+	hlock = find_held_lock(curr, lock, depth, &i);
+	if (!hlock) {
+		print_lock_contention_bug(curr, lock, _RET_IP_);
+		return;
+	}
+
+	if (hlock->instance != lock)
+		return;
+
+	cpu = smp_processor_id();
+	if (hlock->waittime_stamp) {
+		now = lockstat_clock();
+		waittime = now - hlock->waittime_stamp;
+		hlock->holdtime_stamp = now;
+	}
+
+	stats = get_lock_stats(hlock_class(hlock));
+	if (waittime) {
+		if (hlock->read)
+			lock_time_inc(&stats->read_waittime, waittime);
+		else
+			lock_time_inc(&stats->write_waittime, waittime);
+	}
+	if (lock->cpu != cpu)
+		stats->bounces[bounce_acquired + !!hlock->read]++;
+
+	lock->cpu = cpu;
+	lock->ip = ip;
+}
+
+void lock_contended(struct lockdep_map *lock, unsigned long ip)
+{
+	unsigned long flags;
+
+	trace_lock_contended(lock, ip);
+
+	if (unlikely(!lock_stat || !lockdep_enabled()))
+		return;
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+	lockdep_recursion_inc();
+	__lock_contended(lock, ip);
+	lockdep_recursion_finish();
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_contended);
+
+void lock_acquired(struct lockdep_map *lock, unsigned long ip)
+{
+	unsigned long flags;
+
+	trace_lock_acquired(lock, ip);
+
+	if (unlikely(!lock_stat || !lockdep_enabled()))
+		return;
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+	lockdep_recursion_inc();
+	__lock_acquired(lock, ip);
+	lockdep_recursion_finish();
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_acquired);
+#endif
+
+/*
+ * Used by the testsuite, sanitize the validator state
+ * after a simulated failure:
+ */
+
+void lockdep_reset(void)
+{
+	unsigned long flags;
+	int i;
+
+	raw_local_irq_save(flags);
+	lockdep_init_task(current);
+	memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
+	nr_hardirq_chains = 0;
+	nr_softirq_chains = 0;
+	nr_process_chains = 0;
+	debug_locks = 1;
+	for (i = 0; i < CHAINHASH_SIZE; i++)
+		INIT_HLIST_HEAD(chainhash_table + i);
+	raw_local_irq_restore(flags);
+}
+
+/* Remove a class from a lock chain. Must be called with the graph lock held. */
+static void remove_class_from_lock_chain(struct pending_free *pf,
+					 struct lock_chain *chain,
+					 struct lock_class *class)
+{
+#ifdef CONFIG_PROVE_LOCKING
+	int i;
+
+	for (i = chain->base; i < chain->base + chain->depth; i++) {
+		if (chain_hlock_class_idx(chain_hlocks[i]) != class - lock_classes)
+			continue;
+		/*
+		 * Each lock class occurs at most once in a lock chain so once
+		 * we found a match we can break out of this loop.
+		 */
+		goto free_lock_chain;
+	}
+	/* Since the chain has not been modified, return. */
+	return;
+
+free_lock_chain:
+	free_chain_hlocks(chain->base, chain->depth);
+	/* Overwrite the chain key for concurrent RCU readers. */
+	WRITE_ONCE(chain->chain_key, INITIAL_CHAIN_KEY);
+	dec_chains(chain->irq_context);
+
+	/*
+	 * Note: calling hlist_del_rcu() from inside a
+	 * hlist_for_each_entry_rcu() loop is safe.
+	 */
+	hlist_del_rcu(&chain->entry);
+	__set_bit(chain - lock_chains, pf->lock_chains_being_freed);
+	nr_zapped_lock_chains++;
+#endif
+}
+
+/* Must be called with the graph lock held. */
+static void remove_class_from_lock_chains(struct pending_free *pf,
+					  struct lock_class *class)
+{
+	struct lock_chain *chain;
+	struct hlist_head *head;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(chainhash_table); i++) {
+		head = chainhash_table + i;
+		hlist_for_each_entry_rcu(chain, head, entry) {
+			remove_class_from_lock_chain(pf, chain, class);
+		}
+	}
+}
+
+/*
+ * Remove all references to a lock class. The caller must hold the graph lock.
+ */
+static void zap_class(struct pending_free *pf, struct lock_class *class)
+{
+	struct lock_list *entry;
+	int i;
+
+	WARN_ON_ONCE(!class->key);
+
+	/*
+	 * Remove all dependencies this lock is
+	 * involved in:
+	 */
+	for_each_set_bit(i, list_entries_in_use, ARRAY_SIZE(list_entries)) {
+		entry = list_entries + i;
+		if (entry->class != class && entry->links_to != class)
+			continue;
+		__clear_bit(i, list_entries_in_use);
+		nr_list_entries--;
+		list_del_rcu(&entry->entry);
+	}
+	if (list_empty(&class->locks_after) &&
+	    list_empty(&class->locks_before)) {
+		list_move_tail(&class->lock_entry, &pf->zapped);
+		hlist_del_rcu(&class->hash_entry);
+		WRITE_ONCE(class->key, NULL);
+		WRITE_ONCE(class->name, NULL);
+		nr_lock_classes--;
+		__clear_bit(class - lock_classes, lock_classes_in_use);
+		if (class - lock_classes == max_lock_class_idx)
+			max_lock_class_idx--;
+	} else {
+		WARN_ONCE(true, "%s() failed for class %s\n", __func__,
+			  class->name);
+	}
+
+	remove_class_from_lock_chains(pf, class);
+	nr_zapped_classes++;
+}
+
+static void reinit_class(struct lock_class *class)
+{
+	WARN_ON_ONCE(!class->lock_entry.next);
+	WARN_ON_ONCE(!list_empty(&class->locks_after));
+	WARN_ON_ONCE(!list_empty(&class->locks_before));
+	memset_startat(class, 0, key);
+	WARN_ON_ONCE(!class->lock_entry.next);
+	WARN_ON_ONCE(!list_empty(&class->locks_after));
+	WARN_ON_ONCE(!list_empty(&class->locks_before));
+}
+
+static inline int within(const void *addr, void *start, unsigned long size)
+{
+	return addr >= start && addr < start + size;
+}
+
+static bool inside_selftest(void)
+{
+	return current == lockdep_selftest_task_struct;
+}
+
+/* The caller must hold the graph lock. */
+static struct pending_free *get_pending_free(void)
+{
+	return delayed_free.pf + delayed_free.index;
+}
+
+static void free_zapped_rcu(struct rcu_head *cb);
+
+/*
+ * Schedule an RCU callback if no RCU callback is pending. Must be called with
+ * the graph lock held.
+ */
+static void call_rcu_zapped(struct pending_free *pf)
+{
+	WARN_ON_ONCE(inside_selftest());
+
+	if (list_empty(&pf->zapped))
+		return;
+
+	if (delayed_free.scheduled)
+		return;
+
+	delayed_free.scheduled = true;
+
+	WARN_ON_ONCE(delayed_free.pf + delayed_free.index != pf);
+	delayed_free.index ^= 1;
+
+	call_rcu(&delayed_free.rcu_head, free_zapped_rcu);
+}
+
+/* The caller must hold the graph lock. May be called from RCU context. */
+static void __free_zapped_classes(struct pending_free *pf)
+{
+	struct lock_class *class;
+
+	check_data_structures();
+
+	list_for_each_entry(class, &pf->zapped, lock_entry)
+		reinit_class(class);
+
+	list_splice_init(&pf->zapped, &free_lock_classes);
+
+#ifdef CONFIG_PROVE_LOCKING
+	bitmap_andnot(lock_chains_in_use, lock_chains_in_use,
+		      pf->lock_chains_being_freed, ARRAY_SIZE(lock_chains));
+	bitmap_clear(pf->lock_chains_being_freed, 0, ARRAY_SIZE(lock_chains));
+#endif
+}
+
+static void free_zapped_rcu(struct rcu_head *ch)
+{
+	struct pending_free *pf;
+	unsigned long flags;
+
+	if (WARN_ON_ONCE(ch != &delayed_free.rcu_head))
+		return;
+
+	raw_local_irq_save(flags);
+	lockdep_lock();
+
+	/* closed head */
+	pf = delayed_free.pf + (delayed_free.index ^ 1);
+	__free_zapped_classes(pf);
+	delayed_free.scheduled = false;
+
+	/*
+	 * If there's anything on the open list, close and start a new callback.
+	 */
+	call_rcu_zapped(delayed_free.pf + delayed_free.index);
+
+	lockdep_unlock();
+	raw_local_irq_restore(flags);
+}
+
+/*
+ * Remove all lock classes from the class hash table and from the
+ * all_lock_classes list whose key or name is in the address range [start,
+ * start + size). Move these lock classes to the zapped_classes list. Must
+ * be called with the graph lock held.
+ */
+static void __lockdep_free_key_range(struct pending_free *pf, void *start,
+				     unsigned long size)
+{
+	struct lock_class *class;
+	struct hlist_head *head;
+	int i;
+
+	/* Unhash all classes that were created by a module. */
+	for (i = 0; i < CLASSHASH_SIZE; i++) {
+		head = classhash_table + i;
+		hlist_for_each_entry_rcu(class, head, hash_entry) {
+			if (!within(class->key, start, size) &&
+			    !within(class->name, start, size))
+				continue;
+			zap_class(pf, class);
+		}
+	}
+}
+
+/*
+ * Used in module.c to remove lock classes from memory that is going to be
+ * freed; and possibly re-used by other modules.
+ *
+ * We will have had one synchronize_rcu() before getting here, so we're
+ * guaranteed nobody will look up these exact classes -- they're properly dead
+ * but still allocated.
+ */
+static void lockdep_free_key_range_reg(void *start, unsigned long size)
+{
+	struct pending_free *pf;
+	unsigned long flags;
+
+	init_data_structures_once();
+
+	raw_local_irq_save(flags);
+	lockdep_lock();
+	pf = get_pending_free();
+	__lockdep_free_key_range(pf, start, size);
+	call_rcu_zapped(pf);
+	lockdep_unlock();
+	raw_local_irq_restore(flags);
+
+	/*
+	 * Wait for any possible iterators from look_up_lock_class() to pass
+	 * before continuing to free the memory they refer to.
+	 */
+	synchronize_rcu();
+}
+
+/*
+ * Free all lockdep keys in the range [start, start+size). Does not sleep.
+ * Ignores debug_locks. Must only be used by the lockdep selftests.
+ */
+static void lockdep_free_key_range_imm(void *start, unsigned long size)
+{
+	struct pending_free *pf = delayed_free.pf;
+	unsigned long flags;
+
+	init_data_structures_once();
+
+	raw_local_irq_save(flags);
+	lockdep_lock();
+	__lockdep_free_key_range(pf, start, size);
+	__free_zapped_classes(pf);
+	lockdep_unlock();
+	raw_local_irq_restore(flags);
+}
+
+void lockdep_free_key_range(void *start, unsigned long size)
+{
+	init_data_structures_once();
+
+	if (inside_selftest())
+		lockdep_free_key_range_imm(start, size);
+	else
+		lockdep_free_key_range_reg(start, size);
+}
+
+/*
+ * Check whether any element of the @lock->class_cache[] array refers to a
+ * registered lock class. The caller must hold either the graph lock or the
+ * RCU read lock.
+ */
+static bool lock_class_cache_is_registered(struct lockdep_map *lock)
+{
+	struct lock_class *class;
+	struct hlist_head *head;
+	int i, j;
+
+	for (i = 0; i < CLASSHASH_SIZE; i++) {
+		head = classhash_table + i;
+		hlist_for_each_entry_rcu(class, head, hash_entry) {
+			for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
+				if (lock->class_cache[j] == class)
+					return true;
+		}
+	}
+	return false;
+}
+
+/* The caller must hold the graph lock. Does not sleep. */
+static void __lockdep_reset_lock(struct pending_free *pf,
+				 struct lockdep_map *lock)
+{
+	struct lock_class *class;
+	int j;
+
+	/*
+	 * Remove all classes this lock might have:
+	 */
+	for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
+		/*
+		 * If the class exists we look it up and zap it:
+		 */
+		class = look_up_lock_class(lock, j);
+		if (class)
+			zap_class(pf, class);
+	}
+	/*
+	 * Debug check: in the end all mapped classes should
+	 * be gone.
+	 */
+	if (WARN_ON_ONCE(lock_class_cache_is_registered(lock)))
+		debug_locks_off();
+}
+
+/*
+ * Remove all information lockdep has about a lock if debug_locks == 1. Free
+ * released data structures from RCU context.
+ */
+static void lockdep_reset_lock_reg(struct lockdep_map *lock)
+{
+	struct pending_free *pf;
+	unsigned long flags;
+	int locked;
+
+	raw_local_irq_save(flags);
+	locked = graph_lock();
+	if (!locked)
+		goto out_irq;
+
+	pf = get_pending_free();
+	__lockdep_reset_lock(pf, lock);
+	call_rcu_zapped(pf);
+
+	graph_unlock();
+out_irq:
+	raw_local_irq_restore(flags);
+}
+
+/*
+ * Reset a lock. Does not sleep. Ignores debug_locks. Must only be used by the
+ * lockdep selftests.
+ */
+static void lockdep_reset_lock_imm(struct lockdep_map *lock)
+{
+	struct pending_free *pf = delayed_free.pf;
+	unsigned long flags;
+
+	raw_local_irq_save(flags);
+	lockdep_lock();
+	__lockdep_reset_lock(pf, lock);
+	__free_zapped_classes(pf);
+	lockdep_unlock();
+	raw_local_irq_restore(flags);
+}
+
+void lockdep_reset_lock(struct lockdep_map *lock)
+{
+	init_data_structures_once();
+
+	if (inside_selftest())
+		lockdep_reset_lock_imm(lock);
+	else
+		lockdep_reset_lock_reg(lock);
+}
+
+/*
+ * Unregister a dynamically allocated key.
+ *
+ * Unlike lockdep_register_key(), a search is always done to find a matching
+ * key irrespective of debug_locks to avoid potential invalid access to freed
+ * memory in lock_class entry.
+ */
+void lockdep_unregister_key(struct lock_class_key *key)
+{
+	struct hlist_head *hash_head = keyhashentry(key);
+	struct lock_class_key *k;
+	struct pending_free *pf;
+	unsigned long flags;
+	bool found = false;
+
+	might_sleep();
+
+	if (WARN_ON_ONCE(static_obj(key)))
+		return;
+
+	raw_local_irq_save(flags);
+	lockdep_lock();
+
+	hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
+		if (k == key) {
+			hlist_del_rcu(&k->hash_entry);
+			found = true;
+			break;
+		}
+	}
+	WARN_ON_ONCE(!found && debug_locks);
+	if (found) {
+		pf = get_pending_free();
+		__lockdep_free_key_range(pf, key, 1);
+		call_rcu_zapped(pf);
+	}
+	lockdep_unlock();
+	raw_local_irq_restore(flags);
+
+	/* Wait until is_dynamic_key() has finished accessing k->hash_entry. */
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(lockdep_unregister_key);
+
+void __init lockdep_init(void)
+{
+	printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
+
+	printk("... MAX_LOCKDEP_SUBCLASSES:  %lu\n", MAX_LOCKDEP_SUBCLASSES);
+	printk("... MAX_LOCK_DEPTH:          %lu\n", MAX_LOCK_DEPTH);
+	printk("... MAX_LOCKDEP_KEYS:        %lu\n", MAX_LOCKDEP_KEYS);
+	printk("... CLASSHASH_SIZE:          %lu\n", CLASSHASH_SIZE);
+	printk("... MAX_LOCKDEP_ENTRIES:     %lu\n", MAX_LOCKDEP_ENTRIES);
+	printk("... MAX_LOCKDEP_CHAINS:      %lu\n", MAX_LOCKDEP_CHAINS);
+	printk("... CHAINHASH_SIZE:          %lu\n", CHAINHASH_SIZE);
+
+	printk(" memory used by lock dependency info: %zu kB\n",
+	       (sizeof(lock_classes) +
+		sizeof(lock_classes_in_use) +
+		sizeof(classhash_table) +
+		sizeof(list_entries) +
+		sizeof(list_entries_in_use) +
+		sizeof(chainhash_table) +
+		sizeof(delayed_free)
+#ifdef CONFIG_PROVE_LOCKING
+		+ sizeof(lock_cq)
+		+ sizeof(lock_chains)
+		+ sizeof(lock_chains_in_use)
+		+ sizeof(chain_hlocks)
+#endif
+		) / 1024
+		);
+
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+	printk(" memory used for stack traces: %zu kB\n",
+	       (sizeof(stack_trace) + sizeof(stack_trace_hash)) / 1024
+	       );
+#endif
+
+	printk(" per task-struct memory footprint: %zu bytes\n",
+	       sizeof(((struct task_struct *)NULL)->held_locks));
+}
+
+static void
+print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
+		     const void *mem_to, struct held_lock *hlock)
+{
+	if (!debug_locks_off())
+		return;
+	if (debug_locks_silent)
+		return;
+
+	pr_warn("\n");
+	pr_warn("=========================\n");
+	pr_warn("WARNING: held lock freed!\n");
+	print_kernel_ident();
+	pr_warn("-------------------------\n");
+	pr_warn("%s/%d is freeing memory %px-%px, with a lock still held there!\n",
+		curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
+	print_lock(hlock);
+	lockdep_print_held_locks(curr);
+
+	pr_warn("\nstack backtrace:\n");
+	dump_stack();
+}
+
+static inline int not_in_range(const void* mem_from, unsigned long mem_len,
+				const void* lock_from, unsigned long lock_len)
+{
+	return lock_from + lock_len <= mem_from ||
+		mem_from + mem_len <= lock_from;
+}
+
+/*
+ * Called when kernel memory is freed (or unmapped), or if a lock
+ * is destroyed or reinitialized - this code checks whether there is
+ * any held lock in the memory range of <from> to <to>:
+ */
+void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
+{
+	struct task_struct *curr = current;
+	struct held_lock *hlock;
+	unsigned long flags;
+	int i;
+
+	if (unlikely(!debug_locks))
+		return;
+
+	raw_local_irq_save(flags);
+	for (i = 0; i < curr->lockdep_depth; i++) {
+		hlock = curr->held_locks + i;
+
+		if (not_in_range(mem_from, mem_len, hlock->instance,
+					sizeof(*hlock->instance)))
+			continue;
+
+		print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock);
+		break;
+	}
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
+
+static void print_held_locks_bug(void)
+{
+	if (!debug_locks_off())
+		return;
+	if (debug_locks_silent)
+		return;
+
+	pr_warn("\n");
+	pr_warn("====================================\n");
+	pr_warn("WARNING: %s/%d still has locks held!\n",
+	       current->comm, task_pid_nr(current));
+	print_kernel_ident();
+	pr_warn("------------------------------------\n");
+	lockdep_print_held_locks(current);
+	pr_warn("\nstack backtrace:\n");
+	dump_stack();
+}
+
+void debug_check_no_locks_held(void)
+{
+	if (unlikely(current->lockdep_depth > 0))
+		print_held_locks_bug();
+}
+EXPORT_SYMBOL_GPL(debug_check_no_locks_held);
+
+#ifdef __KERNEL__
+void debug_show_all_locks(void)
+{
+	struct task_struct *g, *p;
+
+	if (unlikely(!debug_locks)) {
+		pr_warn("INFO: lockdep is turned off.\n");
+		return;
+	}
+	pr_warn("\nShowing all locks held in the system:\n");
+
+	rcu_read_lock();
+	for_each_process_thread(g, p) {
+		if (!p->lockdep_depth)
+			continue;
+		lockdep_print_held_locks(p);
+		touch_nmi_watchdog();
+		touch_all_softlockup_watchdogs();
+	}
+	rcu_read_unlock();
+
+	pr_warn("\n");
+	pr_warn("=============================================\n\n");
+}
+EXPORT_SYMBOL_GPL(debug_show_all_locks);
+#endif
+
+/*
+ * Careful: only use this function if you are sure that
+ * the task cannot run in parallel!
+ */
+void debug_show_held_locks(struct task_struct *task)
+{
+	if (unlikely(!debug_locks)) {
+		printk("INFO: lockdep is turned off.\n");
+		return;
+	}
+	lockdep_print_held_locks(task);
+}
+EXPORT_SYMBOL_GPL(debug_show_held_locks);
+
+asmlinkage __visible void lockdep_sys_exit(void)
+{
+	struct task_struct *curr = current;
+
+	if (unlikely(curr->lockdep_depth)) {
+		if (!debug_locks_off())
+			return;
+		pr_warn("\n");
+		pr_warn("================================================\n");
+		pr_warn("WARNING: lock held when returning to user space!\n");
+		print_kernel_ident();
+		pr_warn("------------------------------------------------\n");
+		pr_warn("%s/%d is leaving the kernel with locks still held!\n",
+				curr->comm, curr->pid);
+		lockdep_print_held_locks(curr);
+	}
+
+	/*
+	 * The lock history for each syscall should be independent. So wipe the
+	 * slate clean on return to userspace.
+	 */
+	lockdep_invariant_state(false);
+}
+
+void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
+{
+	struct task_struct *curr = current;
+	int dl = READ_ONCE(debug_locks);
+	bool rcu = warn_rcu_enter();
+
+	/* Note: the following can be executed concurrently, so be careful. */
+	pr_warn("\n");
+	pr_warn("=============================\n");
+	pr_warn("WARNING: suspicious RCU usage\n");
+	print_kernel_ident();
+	pr_warn("-----------------------------\n");
+	pr_warn("%s:%d %s!\n", file, line, s);
+	pr_warn("\nother info that might help us debug this:\n\n");
+	pr_warn("\n%srcu_scheduler_active = %d, debug_locks = %d\n%s",
+	       !rcu_lockdep_current_cpu_online()
+			? "RCU used illegally from offline CPU!\n"
+			: "",
+	       rcu_scheduler_active, dl,
+	       dl ? "" : "Possible false positive due to lockdep disabling via debug_locks = 0\n");
+
+	/*
+	 * If a CPU is in the RCU-free window in idle (ie: in the section
+	 * between ct_idle_enter() and ct_idle_exit(), then RCU
+	 * considers that CPU to be in an "extended quiescent state",
+	 * which means that RCU will be completely ignoring that CPU.
+	 * Therefore, rcu_read_lock() and friends have absolutely no
+	 * effect on a CPU running in that state. In other words, even if
+	 * such an RCU-idle CPU has called rcu_read_lock(), RCU might well
+	 * delete data structures out from under it.  RCU really has no
+	 * choice here: we need to keep an RCU-free window in idle where
+	 * the CPU may possibly enter into low power mode. This way we can
+	 * notice an extended quiescent state to other CPUs that started a grace
+	 * period. Otherwise we would delay any grace period as long as we run
+	 * in the idle task.
+	 *
+	 * So complain bitterly if someone does call rcu_read_lock(),
+	 * rcu_read_lock_bh() and so on from extended quiescent states.
+	 */
+	if (!rcu_is_watching())
+		pr_warn("RCU used illegally from extended quiescent state!\n");
+
+	lockdep_print_held_locks(curr);
+	pr_warn("\nstack backtrace:\n");
+	dump_stack();
+	warn_rcu_exit(rcu);
+}
+EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
new file mode 100644
index 000000000..bbe900026
--- /dev/null
+++ b/kernel/locking/lockdep_internals.h
@@ -0,0 +1,261 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * kernel/lockdep_internals.h
+ *
+ * Runtime locking correctness validator
+ *
+ * lockdep subsystem internal functions and variables.
+ */
+
+/*
+ * Lock-class usage-state bits:
+ */
+enum lock_usage_bit {
+#define LOCKDEP_STATE(__STATE)		\
+	LOCK_USED_IN_##__STATE,		\
+	LOCK_USED_IN_##__STATE##_READ,	\
+	LOCK_ENABLED_##__STATE,		\
+	LOCK_ENABLED_##__STATE##_READ,
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+	LOCK_USED,
+	LOCK_USED_READ,
+	LOCK_USAGE_STATES,
+};
+
+/* states after LOCK_USED_READ are not traced and printed */
+static_assert(LOCK_TRACE_STATES == LOCK_USAGE_STATES);
+
+#define LOCK_USAGE_READ_MASK 1
+#define LOCK_USAGE_DIR_MASK  2
+#define LOCK_USAGE_STATE_MASK (~(LOCK_USAGE_READ_MASK | LOCK_USAGE_DIR_MASK))
+
+/*
+ * Usage-state bitmasks:
+ */
+#define __LOCKF(__STATE)	LOCKF_##__STATE = (1 << LOCK_##__STATE),
+
+enum {
+#define LOCKDEP_STATE(__STATE)						\
+	__LOCKF(USED_IN_##__STATE)					\
+	__LOCKF(USED_IN_##__STATE##_READ)				\
+	__LOCKF(ENABLED_##__STATE)					\
+	__LOCKF(ENABLED_##__STATE##_READ)
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+	__LOCKF(USED)
+	__LOCKF(USED_READ)
+};
+
+#define LOCKDEP_STATE(__STATE)	LOCKF_ENABLED_##__STATE |
+static const unsigned long LOCKF_ENABLED_IRQ =
+#include "lockdep_states.h"
+	0;
+#undef LOCKDEP_STATE
+
+#define LOCKDEP_STATE(__STATE)	LOCKF_USED_IN_##__STATE |
+static const unsigned long LOCKF_USED_IN_IRQ =
+#include "lockdep_states.h"
+	0;
+#undef LOCKDEP_STATE
+
+#define LOCKDEP_STATE(__STATE)	LOCKF_ENABLED_##__STATE##_READ |
+static const unsigned long LOCKF_ENABLED_IRQ_READ =
+#include "lockdep_states.h"
+	0;
+#undef LOCKDEP_STATE
+
+#define LOCKDEP_STATE(__STATE)	LOCKF_USED_IN_##__STATE##_READ |
+static const unsigned long LOCKF_USED_IN_IRQ_READ =
+#include "lockdep_states.h"
+	0;
+#undef LOCKDEP_STATE
+
+#define LOCKF_ENABLED_IRQ_ALL (LOCKF_ENABLED_IRQ | LOCKF_ENABLED_IRQ_READ)
+#define LOCKF_USED_IN_IRQ_ALL (LOCKF_USED_IN_IRQ | LOCKF_USED_IN_IRQ_READ)
+
+#define LOCKF_IRQ (LOCKF_ENABLED_IRQ | LOCKF_USED_IN_IRQ)
+#define LOCKF_IRQ_READ (LOCKF_ENABLED_IRQ_READ | LOCKF_USED_IN_IRQ_READ)
+
+/*
+ * CONFIG_LOCKDEP_SMALL is defined for sparc. Sparc requires .text,
+ * .data and .bss to fit in required 32MB limit for the kernel. With
+ * CONFIG_LOCKDEP we could go over this limit and cause system boot-up problems.
+ * So, reduce the static allocations for lockdeps related structures so that
+ * everything fits in current required size limit.
+ */
+#ifdef CONFIG_LOCKDEP_SMALL
+/*
+ * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
+ * we track.
+ *
+ * We use the per-lock dependency maps in two ways: we grow it by adding
+ * every to-be-taken lock to all currently held lock's own dependency
+ * table (if it's not there yet), and we check it for lock order
+ * conflicts and deadlocks.
+ */
+#define MAX_LOCKDEP_ENTRIES	16384UL
+#define MAX_LOCKDEP_CHAINS_BITS	15
+#define MAX_STACK_TRACE_ENTRIES	262144UL
+#define STACK_TRACE_HASH_SIZE	8192
+#else
+#define MAX_LOCKDEP_ENTRIES	(1UL << CONFIG_LOCKDEP_BITS)
+
+#define MAX_LOCKDEP_CHAINS_BITS	CONFIG_LOCKDEP_CHAINS_BITS
+
+/*
+ * Stack-trace: tightly packed array of stack backtrace
+ * addresses. Protected by the hash_lock.
+ */
+#define MAX_STACK_TRACE_ENTRIES	(1UL << CONFIG_LOCKDEP_STACK_TRACE_BITS)
+#define STACK_TRACE_HASH_SIZE	(1 << CONFIG_LOCKDEP_STACK_TRACE_HASH_BITS)
+#endif
+
+/*
+ * Bit definitions for lock_chain.irq_context
+ */
+#define LOCK_CHAIN_SOFTIRQ_CONTEXT	(1 << 0)
+#define LOCK_CHAIN_HARDIRQ_CONTEXT	(1 << 1)
+
+#define MAX_LOCKDEP_CHAINS	(1UL << MAX_LOCKDEP_CHAINS_BITS)
+
+#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
+
+extern struct lock_chain lock_chains[];
+
+#define LOCK_USAGE_CHARS (2*XXX_LOCK_USAGE_STATES + 1)
+
+extern void get_usage_chars(struct lock_class *class,
+			    char usage[LOCK_USAGE_CHARS]);
+
+extern const char *__get_key_name(const struct lockdep_subclass_key *key,
+				  char *str);
+
+struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);
+
+extern unsigned long nr_lock_classes;
+extern unsigned long nr_zapped_classes;
+extern unsigned long nr_zapped_lock_chains;
+extern unsigned long nr_list_entries;
+long lockdep_next_lockchain(long i);
+unsigned long lock_chain_count(void);
+extern unsigned long nr_stack_trace_entries;
+
+extern unsigned int nr_hardirq_chains;
+extern unsigned int nr_softirq_chains;
+extern unsigned int nr_process_chains;
+extern unsigned int nr_free_chain_hlocks;
+extern unsigned int nr_lost_chain_hlocks;
+extern unsigned int nr_large_chain_blocks;
+
+extern unsigned int max_lockdep_depth;
+extern unsigned int max_bfs_queue_depth;
+extern unsigned long max_lock_class_idx;
+
+extern struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
+extern unsigned long lock_classes_in_use[];
+
+#ifdef CONFIG_PROVE_LOCKING
+extern unsigned long lockdep_count_forward_deps(struct lock_class *);
+extern unsigned long lockdep_count_backward_deps(struct lock_class *);
+#ifdef CONFIG_TRACE_IRQFLAGS
+u64 lockdep_stack_trace_count(void);
+u64 lockdep_stack_hash_count(void);
+#endif
+#else
+static inline unsigned long
+lockdep_count_forward_deps(struct lock_class *class)
+{
+	return 0;
+}
+static inline unsigned long
+lockdep_count_backward_deps(struct lock_class *class)
+{
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+
+#include <asm/local.h>
+/*
+ * Various lockdep statistics.
+ * We want them per cpu as they are often accessed in fast path
+ * and we want to avoid too much cache bouncing.
+ */
+struct lockdep_stats {
+	unsigned long  chain_lookup_hits;
+	unsigned int   chain_lookup_misses;
+	unsigned long  hardirqs_on_events;
+	unsigned long  hardirqs_off_events;
+	unsigned long  redundant_hardirqs_on;
+	unsigned long  redundant_hardirqs_off;
+	unsigned long  softirqs_on_events;
+	unsigned long  softirqs_off_events;
+	unsigned long  redundant_softirqs_on;
+	unsigned long  redundant_softirqs_off;
+	int            nr_unused_locks;
+	unsigned int   nr_redundant_checks;
+	unsigned int   nr_redundant;
+	unsigned int   nr_cyclic_checks;
+	unsigned int   nr_find_usage_forwards_checks;
+	unsigned int   nr_find_usage_backwards_checks;
+
+	/*
+	 * Per lock class locking operation stat counts
+	 */
+	unsigned long lock_class_ops[MAX_LOCKDEP_KEYS];
+};
+
+DECLARE_PER_CPU(struct lockdep_stats, lockdep_stats);
+
+#define __debug_atomic_inc(ptr)					\
+	this_cpu_inc(lockdep_stats.ptr);
+
+#define debug_atomic_inc(ptr)			{		\
+	WARN_ON_ONCE(!irqs_disabled());				\
+	__this_cpu_inc(lockdep_stats.ptr);			\
+}
+
+#define debug_atomic_dec(ptr)			{		\
+	WARN_ON_ONCE(!irqs_disabled());				\
+	__this_cpu_dec(lockdep_stats.ptr);			\
+}
+
+#define debug_atomic_read(ptr)		({				\
+	struct lockdep_stats *__cpu_lockdep_stats;			\
+	unsigned long long __total = 0;					\
+	int __cpu;							\
+	for_each_possible_cpu(__cpu) {					\
+		__cpu_lockdep_stats = &per_cpu(lockdep_stats, __cpu);	\
+		__total += __cpu_lockdep_stats->ptr;			\
+	}								\
+	__total;							\
+})
+
+static inline void debug_class_ops_inc(struct lock_class *class)
+{
+	int idx;
+
+	idx = class - lock_classes;
+	__debug_atomic_inc(lock_class_ops[idx]);
+}
+
+static inline unsigned long debug_class_ops_read(struct lock_class *class)
+{
+	int idx, cpu;
+	unsigned long ops = 0;
+
+	idx = class - lock_classes;
+	for_each_possible_cpu(cpu)
+		ops += per_cpu(lockdep_stats.lock_class_ops[idx], cpu);
+	return ops;
+}
+
+#else
+# define __debug_atomic_inc(ptr)	do { } while (0)
+# define debug_atomic_inc(ptr)		do { } while (0)
+# define debug_atomic_dec(ptr)		do { } while (0)
+# define debug_atomic_read(ptr)		0
+# define debug_class_ops_inc(ptr)	do { } while (0)
+#endif
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
new file mode 100644
index 000000000..15fdc7fa5
--- /dev/null
+++ b/kernel/locking/lockdep_proc.c
@@ -0,0 +1,730 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kernel/lockdep_proc.c
+ *
+ * Runtime locking correctness validator
+ *
+ * Started by Ingo Molnar:
+ *
+ *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
+ *
+ * Code for /proc/lockdep and /proc/lockdep_stats:
+ *
+ */
+#include <linux/export.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/kallsyms.h>
+#include <linux/debug_locks.h>
+#include <linux/vmalloc.h>
+#include <linux/sort.h>
+#include <linux/uaccess.h>
+#include <asm/div64.h>
+
+#include "lockdep_internals.h"
+
+/*
+ * Since iteration of lock_classes is done without holding the lockdep lock,
+ * it is not safe to iterate all_lock_classes list directly as the iteration
+ * may branch off to free_lock_classes or the zapped list. Iteration is done
+ * directly on the lock_classes array by checking the lock_classes_in_use
+ * bitmap and max_lock_class_idx.
+ */
+#define iterate_lock_classes(idx, class)				\
+	for (idx = 0, class = lock_classes; idx <= max_lock_class_idx;	\
+	     idx++, class++)
+
+static void *l_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct lock_class *class = v;
+
+	++class;
+	*pos = class - lock_classes;
+	return (*pos > max_lock_class_idx) ? NULL : class;
+}
+
+static void *l_start(struct seq_file *m, loff_t *pos)
+{
+	unsigned long idx = *pos;
+
+	if (idx > max_lock_class_idx)
+		return NULL;
+	return lock_classes + idx;
+}
+
+static void l_stop(struct seq_file *m, void *v)
+{
+}
+
+static void print_name(struct seq_file *m, struct lock_class *class)
+{
+	char str[KSYM_NAME_LEN];
+	const char *name = class->name;
+
+	if (!name) {
+		name = __get_key_name(class->key, str);
+		seq_printf(m, "%s", name);
+	} else{
+		seq_printf(m, "%s", name);
+		if (class->name_version > 1)
+			seq_printf(m, "#%d", class->name_version);
+		if (class->subclass)
+			seq_printf(m, "/%d", class->subclass);
+	}
+}
+
+static int l_show(struct seq_file *m, void *v)
+{
+	struct lock_class *class = v;
+	struct lock_list *entry;
+	char usage[LOCK_USAGE_CHARS];
+	int idx = class - lock_classes;
+
+	if (v == lock_classes)
+		seq_printf(m, "all lock classes:\n");
+
+	if (!test_bit(idx, lock_classes_in_use))
+		return 0;
+
+	seq_printf(m, "%p", class->key);
+#ifdef CONFIG_DEBUG_LOCKDEP
+	seq_printf(m, " OPS:%8ld", debug_class_ops_read(class));
+#endif
+	if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
+		seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
+		seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
+
+		get_usage_chars(class, usage);
+		seq_printf(m, " %s", usage);
+	}
+
+	seq_printf(m, ": ");
+	print_name(m, class);
+	seq_puts(m, "\n");
+
+	if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
+		list_for_each_entry(entry, &class->locks_after, entry) {
+			if (entry->distance == 1) {
+				seq_printf(m, " -> [%p] ", entry->class->key);
+				print_name(m, entry->class);
+				seq_puts(m, "\n");
+			}
+		}
+		seq_puts(m, "\n");
+	}
+
+	return 0;
+}
+
+static const struct seq_operations lockdep_ops = {
+	.start	= l_start,
+	.next	= l_next,
+	.stop	= l_stop,
+	.show	= l_show,
+};
+
+#ifdef CONFIG_PROVE_LOCKING
+static void *lc_start(struct seq_file *m, loff_t *pos)
+{
+	if (*pos < 0)
+		return NULL;
+
+	if (*pos == 0)
+		return SEQ_START_TOKEN;
+
+	return lock_chains + (*pos - 1);
+}
+
+static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	*pos = lockdep_next_lockchain(*pos - 1) + 1;
+	return lc_start(m, pos);
+}
+
+static void lc_stop(struct seq_file *m, void *v)
+{
+}
+
+static int lc_show(struct seq_file *m, void *v)
+{
+	struct lock_chain *chain = v;
+	struct lock_class *class;
+	int i;
+	static const char * const irq_strs[] = {
+		[0]			     = "0",
+		[LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq",
+		[LOCK_CHAIN_SOFTIRQ_CONTEXT] = "softirq",
+		[LOCK_CHAIN_SOFTIRQ_CONTEXT|
+		 LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq|softirq",
+	};
+
+	if (v == SEQ_START_TOKEN) {
+		if (!nr_free_chain_hlocks)
+			seq_printf(m, "(buggered) ");
+		seq_printf(m, "all lock chains:\n");
+		return 0;
+	}
+
+	seq_printf(m, "irq_context: %s\n", irq_strs[chain->irq_context]);
+
+	for (i = 0; i < chain->depth; i++) {
+		class = lock_chain_get_class(chain, i);
+		if (!class->key)
+			continue;
+
+		seq_printf(m, "[%p] ", class->key);
+		print_name(m, class);
+		seq_puts(m, "\n");
+	}
+	seq_puts(m, "\n");
+
+	return 0;
+}
+
+static const struct seq_operations lockdep_chains_ops = {
+	.start	= lc_start,
+	.next	= lc_next,
+	.stop	= lc_stop,
+	.show	= lc_show,
+};
+#endif /* CONFIG_PROVE_LOCKING */
+
+static void lockdep_stats_debug_show(struct seq_file *m)
+{
+#ifdef CONFIG_DEBUG_LOCKDEP
+	unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
+			   hi2 = debug_atomic_read(hardirqs_off_events),
+			   hr1 = debug_atomic_read(redundant_hardirqs_on),
+			   hr2 = debug_atomic_read(redundant_hardirqs_off),
+			   si1 = debug_atomic_read(softirqs_on_events),
+			   si2 = debug_atomic_read(softirqs_off_events),
+			   sr1 = debug_atomic_read(redundant_softirqs_on),
+			   sr2 = debug_atomic_read(redundant_softirqs_off);
+
+	seq_printf(m, " chain lookup misses:           %11llu\n",
+		debug_atomic_read(chain_lookup_misses));
+	seq_printf(m, " chain lookup hits:             %11llu\n",
+		debug_atomic_read(chain_lookup_hits));
+	seq_printf(m, " cyclic checks:                 %11llu\n",
+		debug_atomic_read(nr_cyclic_checks));
+	seq_printf(m, " redundant checks:              %11llu\n",
+		debug_atomic_read(nr_redundant_checks));
+	seq_printf(m, " redundant links:               %11llu\n",
+		debug_atomic_read(nr_redundant));
+	seq_printf(m, " find-mask forwards checks:     %11llu\n",
+		debug_atomic_read(nr_find_usage_forwards_checks));
+	seq_printf(m, " find-mask backwards checks:    %11llu\n",
+		debug_atomic_read(nr_find_usage_backwards_checks));
+
+	seq_printf(m, " hardirq on events:             %11llu\n", hi1);
+	seq_printf(m, " hardirq off events:            %11llu\n", hi2);
+	seq_printf(m, " redundant hardirq ons:         %11llu\n", hr1);
+	seq_printf(m, " redundant hardirq offs:        %11llu\n", hr2);
+	seq_printf(m, " softirq on events:             %11llu\n", si1);
+	seq_printf(m, " softirq off events:            %11llu\n", si2);
+	seq_printf(m, " redundant softirq ons:         %11llu\n", sr1);
+	seq_printf(m, " redundant softirq offs:        %11llu\n", sr2);
+#endif
+}
+
+static int lockdep_stats_show(struct seq_file *m, void *v)
+{
+	unsigned long nr_unused = 0, nr_uncategorized = 0,
+		      nr_irq_safe = 0, nr_irq_unsafe = 0,
+		      nr_softirq_safe = 0, nr_softirq_unsafe = 0,
+		      nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
+		      nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
+		      nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
+		      nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
+		      sum_forward_deps = 0;
+
+#ifdef CONFIG_PROVE_LOCKING
+	struct lock_class *class;
+	unsigned long idx;
+
+	iterate_lock_classes(idx, class) {
+		if (!test_bit(idx, lock_classes_in_use))
+			continue;
+
+		if (class->usage_mask == 0)
+			nr_unused++;
+		if (class->usage_mask == LOCKF_USED)
+			nr_uncategorized++;
+		if (class->usage_mask & LOCKF_USED_IN_IRQ)
+			nr_irq_safe++;
+		if (class->usage_mask & LOCKF_ENABLED_IRQ)
+			nr_irq_unsafe++;
+		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
+			nr_softirq_safe++;
+		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
+			nr_softirq_unsafe++;
+		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
+			nr_hardirq_safe++;
+		if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
+			nr_hardirq_unsafe++;
+		if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
+			nr_irq_read_safe++;
+		if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
+			nr_irq_read_unsafe++;
+		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
+			nr_softirq_read_safe++;
+		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
+			nr_softirq_read_unsafe++;
+		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
+			nr_hardirq_read_safe++;
+		if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
+			nr_hardirq_read_unsafe++;
+
+		sum_forward_deps += lockdep_count_forward_deps(class);
+	}
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+	DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
+#endif
+
+#endif
+	seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
+			nr_lock_classes, MAX_LOCKDEP_KEYS);
+	seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
+			nr_list_entries, MAX_LOCKDEP_ENTRIES);
+	seq_printf(m, " indirect dependencies:         %11lu\n",
+			sum_forward_deps);
+
+	/*
+	 * Total number of dependencies:
+	 *
+	 * All irq-safe locks may nest inside irq-unsafe locks,
+	 * plus all the other known dependencies:
+	 */
+	seq_printf(m, " all direct dependencies:       %11lu\n",
+			nr_irq_unsafe * nr_irq_safe +
+			nr_hardirq_unsafe * nr_hardirq_safe +
+			nr_list_entries);
+
+#ifdef CONFIG_PROVE_LOCKING
+	seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
+			lock_chain_count(), MAX_LOCKDEP_CHAINS);
+	seq_printf(m, " dependency chain hlocks used:  %11lu [max: %lu]\n",
+			MAX_LOCKDEP_CHAIN_HLOCKS -
+			(nr_free_chain_hlocks + nr_lost_chain_hlocks),
+			MAX_LOCKDEP_CHAIN_HLOCKS);
+	seq_printf(m, " dependency chain hlocks lost:  %11u\n",
+			nr_lost_chain_hlocks);
+#endif
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+	seq_printf(m, " in-hardirq chains:             %11u\n",
+			nr_hardirq_chains);
+	seq_printf(m, " in-softirq chains:             %11u\n",
+			nr_softirq_chains);
+#endif
+	seq_printf(m, " in-process chains:             %11u\n",
+			nr_process_chains);
+	seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
+			nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+	seq_printf(m, " number of stack traces:        %11llu\n",
+		   lockdep_stack_trace_count());
+	seq_printf(m, " number of stack hash chains:   %11llu\n",
+		   lockdep_stack_hash_count());
+#endif
+	seq_printf(m, " combined max dependencies:     %11u\n",
+			(nr_hardirq_chains + 1) *
+			(nr_softirq_chains + 1) *
+			(nr_process_chains + 1)
+	);
+	seq_printf(m, " hardirq-safe locks:            %11lu\n",
+			nr_hardirq_safe);
+	seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
+			nr_hardirq_unsafe);
+	seq_printf(m, " softirq-safe locks:            %11lu\n",
+			nr_softirq_safe);
+	seq_printf(m, " softirq-unsafe locks:          %11lu\n",
+			nr_softirq_unsafe);
+	seq_printf(m, " irq-safe locks:                %11lu\n",
+			nr_irq_safe);
+	seq_printf(m, " irq-unsafe locks:              %11lu\n",
+			nr_irq_unsafe);
+
+	seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
+			nr_hardirq_read_safe);
+	seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
+			nr_hardirq_read_unsafe);
+	seq_printf(m, " softirq-read-safe locks:       %11lu\n",
+			nr_softirq_read_safe);
+	seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
+			nr_softirq_read_unsafe);
+	seq_printf(m, " irq-read-safe locks:           %11lu\n",
+			nr_irq_read_safe);
+	seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
+			nr_irq_read_unsafe);
+
+	seq_printf(m, " uncategorized locks:           %11lu\n",
+			nr_uncategorized);
+	seq_printf(m, " unused locks:                  %11lu\n",
+			nr_unused);
+	seq_printf(m, " max locking depth:             %11u\n",
+			max_lockdep_depth);
+#ifdef CONFIG_PROVE_LOCKING
+	seq_printf(m, " max bfs queue depth:           %11u\n",
+			max_bfs_queue_depth);
+#endif
+	seq_printf(m, " max lock class index:          %11lu\n",
+			max_lock_class_idx);
+	lockdep_stats_debug_show(m);
+	seq_printf(m, " debug_locks:                   %11u\n",
+			debug_locks);
+
+	/*
+	 * Zapped classes and lockdep data buffers reuse statistics.
+	 */
+	seq_puts(m, "\n");
+	seq_printf(m, " zapped classes:                %11lu\n",
+			nr_zapped_classes);
+#ifdef CONFIG_PROVE_LOCKING
+	seq_printf(m, " zapped lock chains:            %11lu\n",
+			nr_zapped_lock_chains);
+	seq_printf(m, " large chain blocks:            %11u\n",
+			nr_large_chain_blocks);
+#endif
+	return 0;
+}
+
+#ifdef CONFIG_LOCK_STAT
+
+struct lock_stat_data {
+	struct lock_class *class;
+	struct lock_class_stats stats;
+};
+
+struct lock_stat_seq {
+	struct lock_stat_data *iter_end;
+	struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
+};
+
+/*
+ * sort on absolute number of contentions
+ */
+static int lock_stat_cmp(const void *l, const void *r)
+{
+	const struct lock_stat_data *dl = l, *dr = r;
+	unsigned long nl, nr;
+
+	nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
+	nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
+
+	return nr - nl;
+}
+
+static void seq_line(struct seq_file *m, char c, int offset, int length)
+{
+	int i;
+
+	for (i = 0; i < offset; i++)
+		seq_puts(m, " ");
+	for (i = 0; i < length; i++)
+		seq_printf(m, "%c", c);
+	seq_puts(m, "\n");
+}
+
+static void snprint_time(char *buf, size_t bufsiz, s64 nr)
+{
+	s64 div;
+	s32 rem;
+
+	nr += 5; /* for display rounding */
+	div = div_s64_rem(nr, 1000, &rem);
+	snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
+}
+
+static void seq_time(struct seq_file *m, s64 time)
+{
+	char num[15];
+
+	snprint_time(num, sizeof(num), time);
+	seq_printf(m, " %14s", num);
+}
+
+static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
+{
+	seq_printf(m, "%14lu", lt->nr);
+	seq_time(m, lt->min);
+	seq_time(m, lt->max);
+	seq_time(m, lt->total);
+	seq_time(m, lt->nr ? div64_u64(lt->total, lt->nr) : 0);
+}
+
+static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
+{
+	const struct lockdep_subclass_key *ckey;
+	struct lock_class_stats *stats;
+	struct lock_class *class;
+	const char *cname;
+	int i, namelen;
+	char name[39];
+
+	class = data->class;
+	stats = &data->stats;
+
+	namelen = 38;
+	if (class->name_version > 1)
+		namelen -= 2; /* XXX truncates versions > 9 */
+	if (class->subclass)
+		namelen -= 2;
+
+	rcu_read_lock_sched();
+	cname = rcu_dereference_sched(class->name);
+	ckey  = rcu_dereference_sched(class->key);
+
+	if (!cname && !ckey) {
+		rcu_read_unlock_sched();
+		return;
+
+	} else if (!cname) {
+		char str[KSYM_NAME_LEN];
+		const char *key_name;
+
+		key_name = __get_key_name(ckey, str);
+		snprintf(name, namelen, "%s", key_name);
+	} else {
+		snprintf(name, namelen, "%s", cname);
+	}
+	rcu_read_unlock_sched();
+
+	namelen = strlen(name);
+	if (class->name_version > 1) {
+		snprintf(name+namelen, 3, "#%d", class->name_version);
+		namelen += 2;
+	}
+	if (class->subclass) {
+		snprintf(name+namelen, 3, "/%d", class->subclass);
+		namelen += 2;
+	}
+
+	if (stats->write_holdtime.nr) {
+		if (stats->read_holdtime.nr)
+			seq_printf(m, "%38s-W:", name);
+		else
+			seq_printf(m, "%40s:", name);
+
+		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
+		seq_lock_time(m, &stats->write_waittime);
+		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
+		seq_lock_time(m, &stats->write_holdtime);
+		seq_puts(m, "\n");
+	}
+
+	if (stats->read_holdtime.nr) {
+		seq_printf(m, "%38s-R:", name);
+		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
+		seq_lock_time(m, &stats->read_waittime);
+		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
+		seq_lock_time(m, &stats->read_holdtime);
+		seq_puts(m, "\n");
+	}
+
+	if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
+		return;
+
+	if (stats->read_holdtime.nr)
+		namelen += 2;
+
+	for (i = 0; i < LOCKSTAT_POINTS; i++) {
+		char ip[32];
+
+		if (class->contention_point[i] == 0)
+			break;
+
+		if (!i)
+			seq_line(m, '-', 40-namelen, namelen);
+
+		snprintf(ip, sizeof(ip), "[<%p>]",
+				(void *)class->contention_point[i]);
+		seq_printf(m, "%40s %14lu %29s %pS\n",
+			   name, stats->contention_point[i],
+			   ip, (void *)class->contention_point[i]);
+	}
+	for (i = 0; i < LOCKSTAT_POINTS; i++) {
+		char ip[32];
+
+		if (class->contending_point[i] == 0)
+			break;
+
+		if (!i)
+			seq_line(m, '-', 40-namelen, namelen);
+
+		snprintf(ip, sizeof(ip), "[<%p>]",
+				(void *)class->contending_point[i]);
+		seq_printf(m, "%40s %14lu %29s %pS\n",
+			   name, stats->contending_point[i],
+			   ip, (void *)class->contending_point[i]);
+	}
+	if (i) {
+		seq_puts(m, "\n");
+		seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1));
+		seq_puts(m, "\n");
+	}
+}
+
+static void seq_header(struct seq_file *m)
+{
+	seq_puts(m, "lock_stat version 0.4\n");
+
+	if (unlikely(!debug_locks))
+		seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
+
+	seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
+	seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
+			"%14s %14s\n",
+			"class name",
+			"con-bounces",
+			"contentions",
+			"waittime-min",
+			"waittime-max",
+			"waittime-total",
+			"waittime-avg",
+			"acq-bounces",
+			"acquisitions",
+			"holdtime-min",
+			"holdtime-max",
+			"holdtime-total",
+			"holdtime-avg");
+	seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
+	seq_printf(m, "\n");
+}
+
+static void *ls_start(struct seq_file *m, loff_t *pos)
+{
+	struct lock_stat_seq *data = m->private;
+	struct lock_stat_data *iter;
+
+	if (*pos == 0)
+		return SEQ_START_TOKEN;
+
+	iter = data->stats + (*pos - 1);
+	if (iter >= data->iter_end)
+		iter = NULL;
+
+	return iter;
+}
+
+static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	(*pos)++;
+	return ls_start(m, pos);
+}
+
+static void ls_stop(struct seq_file *m, void *v)
+{
+}
+
+static int ls_show(struct seq_file *m, void *v)
+{
+	if (v == SEQ_START_TOKEN)
+		seq_header(m);
+	else
+		seq_stats(m, v);
+
+	return 0;
+}
+
+static const struct seq_operations lockstat_ops = {
+	.start	= ls_start,
+	.next	= ls_next,
+	.stop	= ls_stop,
+	.show	= ls_show,
+};
+
+static int lock_stat_open(struct inode *inode, struct file *file)
+{
+	int res;
+	struct lock_class *class;
+	struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
+
+	if (!data)
+		return -ENOMEM;
+
+	res = seq_open(file, &lockstat_ops);
+	if (!res) {
+		struct lock_stat_data *iter = data->stats;
+		struct seq_file *m = file->private_data;
+		unsigned long idx;
+
+		iterate_lock_classes(idx, class) {
+			if (!test_bit(idx, lock_classes_in_use))
+				continue;
+			iter->class = class;
+			iter->stats = lock_stats(class);
+			iter++;
+		}
+
+		data->iter_end = iter;
+
+		sort(data->stats, data->iter_end - data->stats,
+				sizeof(struct lock_stat_data),
+				lock_stat_cmp, NULL);
+
+		m->private = data;
+	} else
+		vfree(data);
+
+	return res;
+}
+
+static ssize_t lock_stat_write(struct file *file, const char __user *buf,
+			       size_t count, loff_t *ppos)
+{
+	struct lock_class *class;
+	unsigned long idx;
+	char c;
+
+	if (count) {
+		if (get_user(c, buf))
+			return -EFAULT;
+
+		if (c != '0')
+			return count;
+
+		iterate_lock_classes(idx, class) {
+			if (!test_bit(idx, lock_classes_in_use))
+				continue;
+			clear_lock_stats(class);
+		}
+	}
+	return count;
+}
+
+static int lock_stat_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq = file->private_data;
+
+	vfree(seq->private);
+	return seq_release(inode, file);
+}
+
+static const struct proc_ops lock_stat_proc_ops = {
+	.proc_open	= lock_stat_open,
+	.proc_write	= lock_stat_write,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= lock_stat_release,
+};
+#endif /* CONFIG_LOCK_STAT */
+
+static int __init lockdep_proc_init(void)
+{
+	proc_create_seq("lockdep", S_IRUSR, NULL, &lockdep_ops);
+#ifdef CONFIG_PROVE_LOCKING
+	proc_create_seq("lockdep_chains", S_IRUSR, NULL, &lockdep_chains_ops);
+#endif
+	proc_create_single("lockdep_stats", S_IRUSR, NULL, lockdep_stats_show);
+#ifdef CONFIG_LOCK_STAT
+	proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL, &lock_stat_proc_ops);
+#endif
+
+	return 0;
+}
+
+__initcall(lockdep_proc_init);
+
diff --git a/kernel/locking/lockdep_states.h b/kernel/locking/lockdep_states.h
new file mode 100644
index 000000000..35ca09f2e
--- /dev/null
+++ b/kernel/locking/lockdep_states.h
@@ -0,0 +1,8 @@
+/*
+ * Lockdep states,
+ *
+ * please update XXX_LOCK_USAGE_STATES in include/linux/lockdep.h whenever
+ * you add one, or come up with a nice dynamic solution.
+ */
+LOCKDEP_STATE(HARDIRQ)
+LOCKDEP_STATE(SOFTIRQ)
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
new file mode 100644
index 000000000..9c2fb613a
--- /dev/null
+++ b/kernel/locking/locktorture.c
@@ -0,0 +1,1117 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Module-based torture test facility for locking
+ *
+ * Copyright (C) IBM Corporation, 2014
+ *
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
+ *          Davidlohr Bueso <dave@stgolabs.net>
+ *	Based on kernel/rcu/torture.c.
+ */
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/sched/rt.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <uapi/linux/sched/types.h>
+#include <linux/rtmutex.h>
+#include <linux/atomic.h>
+#include <linux/moduleparam.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/torture.h>
+#include <linux/reboot.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
+
+torture_param(int, nwriters_stress, -1,
+	     "Number of write-locking stress-test threads");
+torture_param(int, nreaders_stress, -1,
+	     "Number of read-locking stress-test threads");
+torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
+torture_param(int, onoff_interval, 0,
+	     "Time between CPU hotplugs (s), 0=disable");
+torture_param(int, shuffle_interval, 3,
+	     "Number of jiffies between shuffles, 0=disable");
+torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
+torture_param(int, stat_interval, 60,
+	     "Number of seconds between stats printk()s");
+torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
+torture_param(int, verbose, 1,
+	     "Enable verbose debugging printk()s");
+
+static char *torture_type = "spin_lock";
+module_param(torture_type, charp, 0444);
+MODULE_PARM_DESC(torture_type,
+		 "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
+
+static struct task_struct *stats_task;
+static struct task_struct **writer_tasks;
+static struct task_struct **reader_tasks;
+
+static bool lock_is_write_held;
+static atomic_t lock_is_read_held;
+static unsigned long last_lock_release;
+
+struct lock_stress_stats {
+	long n_lock_fail;
+	long n_lock_acquired;
+};
+
+/* Forward reference. */
+static void lock_torture_cleanup(void);
+
+/*
+ * Operations vector for selecting different types of tests.
+ */
+struct lock_torture_ops {
+	void (*init)(void);
+	void (*exit)(void);
+	int (*writelock)(int tid);
+	void (*write_delay)(struct torture_random_state *trsp);
+	void (*task_boost)(struct torture_random_state *trsp);
+	void (*writeunlock)(int tid);
+	int (*readlock)(int tid);
+	void (*read_delay)(struct torture_random_state *trsp);
+	void (*readunlock)(int tid);
+
+	unsigned long flags; /* for irq spinlocks */
+	const char *name;
+};
+
+struct lock_torture_cxt {
+	int nrealwriters_stress;
+	int nrealreaders_stress;
+	bool debug_lock;
+	bool init_called;
+	atomic_t n_lock_torture_errors;
+	struct lock_torture_ops *cur_ops;
+	struct lock_stress_stats *lwsa; /* writer statistics */
+	struct lock_stress_stats *lrsa; /* reader statistics */
+};
+static struct lock_torture_cxt cxt = { 0, 0, false, false,
+				       ATOMIC_INIT(0),
+				       NULL, NULL};
+/*
+ * Definitions for lock torture testing.
+ */
+
+static int torture_lock_busted_write_lock(int tid __maybe_unused)
+{
+	return 0;  /* BUGGY, do not use in real life!!! */
+}
+
+static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
+{
+	const unsigned long longdelay_ms = 100;
+
+	/* We want a long delay occasionally to force massive contention.  */
+	if (!(torture_random(trsp) %
+	      (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+		mdelay(longdelay_ms);
+	if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
+		torture_preempt_schedule();  /* Allow test to be preempted. */
+}
+
+static void torture_lock_busted_write_unlock(int tid __maybe_unused)
+{
+	  /* BUGGY, do not use in real life!!! */
+}
+
+static void torture_boost_dummy(struct torture_random_state *trsp)
+{
+	/* Only rtmutexes care about priority */
+}
+
+static struct lock_torture_ops lock_busted_ops = {
+	.writelock	= torture_lock_busted_write_lock,
+	.write_delay	= torture_lock_busted_write_delay,
+	.task_boost     = torture_boost_dummy,
+	.writeunlock	= torture_lock_busted_write_unlock,
+	.readlock       = NULL,
+	.read_delay     = NULL,
+	.readunlock     = NULL,
+	.name		= "lock_busted"
+};
+
+static DEFINE_SPINLOCK(torture_spinlock);
+
+static int torture_spin_lock_write_lock(int tid __maybe_unused)
+__acquires(torture_spinlock)
+{
+	spin_lock(&torture_spinlock);
+	return 0;
+}
+
+static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
+{
+	const unsigned long shortdelay_us = 2;
+	const unsigned long longdelay_ms = 100;
+
+	/* We want a short delay mostly to emulate likely code, and
+	 * we want a long delay occasionally to force massive contention.
+	 */
+	if (!(torture_random(trsp) %
+	      (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+		mdelay(longdelay_ms);
+	if (!(torture_random(trsp) %
+	      (cxt.nrealwriters_stress * 2 * shortdelay_us)))
+		udelay(shortdelay_us);
+	if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
+		torture_preempt_schedule();  /* Allow test to be preempted. */
+}
+
+static void torture_spin_lock_write_unlock(int tid __maybe_unused)
+__releases(torture_spinlock)
+{
+	spin_unlock(&torture_spinlock);
+}
+
+static struct lock_torture_ops spin_lock_ops = {
+	.writelock	= torture_spin_lock_write_lock,
+	.write_delay	= torture_spin_lock_write_delay,
+	.task_boost     = torture_boost_dummy,
+	.writeunlock	= torture_spin_lock_write_unlock,
+	.readlock       = NULL,
+	.read_delay     = NULL,
+	.readunlock     = NULL,
+	.name		= "spin_lock"
+};
+
+static int torture_spin_lock_write_lock_irq(int tid __maybe_unused)
+__acquires(torture_spinlock)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&torture_spinlock, flags);
+	cxt.cur_ops->flags = flags;
+	return 0;
+}
+
+static void torture_lock_spin_write_unlock_irq(int tid __maybe_unused)
+__releases(torture_spinlock)
+{
+	spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
+}
+
+static struct lock_torture_ops spin_lock_irq_ops = {
+	.writelock	= torture_spin_lock_write_lock_irq,
+	.write_delay	= torture_spin_lock_write_delay,
+	.task_boost     = torture_boost_dummy,
+	.writeunlock	= torture_lock_spin_write_unlock_irq,
+	.readlock       = NULL,
+	.read_delay     = NULL,
+	.readunlock     = NULL,
+	.name		= "spin_lock_irq"
+};
+
+static DEFINE_RWLOCK(torture_rwlock);
+
+static int torture_rwlock_write_lock(int tid __maybe_unused)
+__acquires(torture_rwlock)
+{
+	write_lock(&torture_rwlock);
+	return 0;
+}
+
+static void torture_rwlock_write_delay(struct torture_random_state *trsp)
+{
+	const unsigned long shortdelay_us = 2;
+	const unsigned long longdelay_ms = 100;
+
+	/* We want a short delay mostly to emulate likely code, and
+	 * we want a long delay occasionally to force massive contention.
+	 */
+	if (!(torture_random(trsp) %
+	      (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+		mdelay(longdelay_ms);
+	else
+		udelay(shortdelay_us);
+}
+
+static void torture_rwlock_write_unlock(int tid __maybe_unused)
+__releases(torture_rwlock)
+{
+	write_unlock(&torture_rwlock);
+}
+
+static int torture_rwlock_read_lock(int tid __maybe_unused)
+__acquires(torture_rwlock)
+{
+	read_lock(&torture_rwlock);
+	return 0;
+}
+
+static void torture_rwlock_read_delay(struct torture_random_state *trsp)
+{
+	const unsigned long shortdelay_us = 10;
+	const unsigned long longdelay_ms = 100;
+
+	/* We want a short delay mostly to emulate likely code, and
+	 * we want a long delay occasionally to force massive contention.
+	 */
+	if (!(torture_random(trsp) %
+	      (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
+		mdelay(longdelay_ms);
+	else
+		udelay(shortdelay_us);
+}
+
+static void torture_rwlock_read_unlock(int tid __maybe_unused)
+__releases(torture_rwlock)
+{
+	read_unlock(&torture_rwlock);
+}
+
+static struct lock_torture_ops rw_lock_ops = {
+	.writelock	= torture_rwlock_write_lock,
+	.write_delay	= torture_rwlock_write_delay,
+	.task_boost     = torture_boost_dummy,
+	.writeunlock	= torture_rwlock_write_unlock,
+	.readlock       = torture_rwlock_read_lock,
+	.read_delay     = torture_rwlock_read_delay,
+	.readunlock     = torture_rwlock_read_unlock,
+	.name		= "rw_lock"
+};
+
+static int torture_rwlock_write_lock_irq(int tid __maybe_unused)
+__acquires(torture_rwlock)
+{
+	unsigned long flags;
+
+	write_lock_irqsave(&torture_rwlock, flags);
+	cxt.cur_ops->flags = flags;
+	return 0;
+}
+
+static void torture_rwlock_write_unlock_irq(int tid __maybe_unused)
+__releases(torture_rwlock)
+{
+	write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
+}
+
+static int torture_rwlock_read_lock_irq(int tid __maybe_unused)
+__acquires(torture_rwlock)
+{
+	unsigned long flags;
+
+	read_lock_irqsave(&torture_rwlock, flags);
+	cxt.cur_ops->flags = flags;
+	return 0;
+}
+
+static void torture_rwlock_read_unlock_irq(int tid __maybe_unused)
+__releases(torture_rwlock)
+{
+	read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
+}
+
+static struct lock_torture_ops rw_lock_irq_ops = {
+	.writelock	= torture_rwlock_write_lock_irq,
+	.write_delay	= torture_rwlock_write_delay,
+	.task_boost     = torture_boost_dummy,
+	.writeunlock	= torture_rwlock_write_unlock_irq,
+	.readlock       = torture_rwlock_read_lock_irq,
+	.read_delay     = torture_rwlock_read_delay,
+	.readunlock     = torture_rwlock_read_unlock_irq,
+	.name		= "rw_lock_irq"
+};
+
+static DEFINE_MUTEX(torture_mutex);
+
+static int torture_mutex_lock(int tid __maybe_unused)
+__acquires(torture_mutex)
+{
+	mutex_lock(&torture_mutex);
+	return 0;
+}
+
+static void torture_mutex_delay(struct torture_random_state *trsp)
+{
+	const unsigned long longdelay_ms = 100;
+
+	/* We want a long delay occasionally to force massive contention.  */
+	if (!(torture_random(trsp) %
+	      (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+		mdelay(longdelay_ms * 5);
+	else
+		mdelay(longdelay_ms / 5);
+	if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
+		torture_preempt_schedule();  /* Allow test to be preempted. */
+}
+
+static void torture_mutex_unlock(int tid __maybe_unused)
+__releases(torture_mutex)
+{
+	mutex_unlock(&torture_mutex);
+}
+
+static struct lock_torture_ops mutex_lock_ops = {
+	.writelock	= torture_mutex_lock,
+	.write_delay	= torture_mutex_delay,
+	.task_boost     = torture_boost_dummy,
+	.writeunlock	= torture_mutex_unlock,
+	.readlock       = NULL,
+	.read_delay     = NULL,
+	.readunlock     = NULL,
+	.name		= "mutex_lock"
+};
+
+#include <linux/ww_mutex.h>
+/*
+ * The torture ww_mutexes should belong to the same lock class as
+ * torture_ww_class to avoid lockdep problem. The ww_mutex_init()
+ * function is called for initialization to ensure that.
+ */
+static DEFINE_WD_CLASS(torture_ww_class);
+static struct ww_mutex torture_ww_mutex_0, torture_ww_mutex_1, torture_ww_mutex_2;
+static struct ww_acquire_ctx *ww_acquire_ctxs;
+
+static void torture_ww_mutex_init(void)
+{
+	ww_mutex_init(&torture_ww_mutex_0, &torture_ww_class);
+	ww_mutex_init(&torture_ww_mutex_1, &torture_ww_class);
+	ww_mutex_init(&torture_ww_mutex_2, &torture_ww_class);
+
+	ww_acquire_ctxs = kmalloc_array(cxt.nrealwriters_stress,
+					sizeof(*ww_acquire_ctxs),
+					GFP_KERNEL);
+	if (!ww_acquire_ctxs)
+		VERBOSE_TOROUT_STRING("ww_acquire_ctx: Out of memory");
+}
+
+static void torture_ww_mutex_exit(void)
+{
+	kfree(ww_acquire_ctxs);
+}
+
+static int torture_ww_mutex_lock(int tid)
+__acquires(torture_ww_mutex_0)
+__acquires(torture_ww_mutex_1)
+__acquires(torture_ww_mutex_2)
+{
+	LIST_HEAD(list);
+	struct reorder_lock {
+		struct list_head link;
+		struct ww_mutex *lock;
+	} locks[3], *ll, *ln;
+	struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
+
+	locks[0].lock = &torture_ww_mutex_0;
+	list_add(&locks[0].link, &list);
+
+	locks[1].lock = &torture_ww_mutex_1;
+	list_add(&locks[1].link, &list);
+
+	locks[2].lock = &torture_ww_mutex_2;
+	list_add(&locks[2].link, &list);
+
+	ww_acquire_init(ctx, &torture_ww_class);
+
+	list_for_each_entry(ll, &list, link) {
+		int err;
+
+		err = ww_mutex_lock(ll->lock, ctx);
+		if (!err)
+			continue;
+
+		ln = ll;
+		list_for_each_entry_continue_reverse(ln, &list, link)
+			ww_mutex_unlock(ln->lock);
+
+		if (err != -EDEADLK)
+			return err;
+
+		ww_mutex_lock_slow(ll->lock, ctx);
+		list_move(&ll->link, &list);
+	}
+
+	return 0;
+}
+
+static void torture_ww_mutex_unlock(int tid)
+__releases(torture_ww_mutex_0)
+__releases(torture_ww_mutex_1)
+__releases(torture_ww_mutex_2)
+{
+	struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
+
+	ww_mutex_unlock(&torture_ww_mutex_0);
+	ww_mutex_unlock(&torture_ww_mutex_1);
+	ww_mutex_unlock(&torture_ww_mutex_2);
+	ww_acquire_fini(ctx);
+}
+
+static struct lock_torture_ops ww_mutex_lock_ops = {
+	.init		= torture_ww_mutex_init,
+	.exit		= torture_ww_mutex_exit,
+	.writelock	= torture_ww_mutex_lock,
+	.write_delay	= torture_mutex_delay,
+	.task_boost     = torture_boost_dummy,
+	.writeunlock	= torture_ww_mutex_unlock,
+	.readlock       = NULL,
+	.read_delay     = NULL,
+	.readunlock     = NULL,
+	.name		= "ww_mutex_lock"
+};
+
+#ifdef CONFIG_RT_MUTEXES
+static DEFINE_RT_MUTEX(torture_rtmutex);
+
+static int torture_rtmutex_lock(int tid __maybe_unused)
+__acquires(torture_rtmutex)
+{
+	rt_mutex_lock(&torture_rtmutex);
+	return 0;
+}
+
+static void torture_rtmutex_boost(struct torture_random_state *trsp)
+{
+	const unsigned int factor = 50000; /* yes, quite arbitrary */
+
+	if (!rt_task(current)) {
+		/*
+		 * Boost priority once every ~50k operations. When the
+		 * task tries to take the lock, the rtmutex it will account
+		 * for the new priority, and do any corresponding pi-dance.
+		 */
+		if (trsp && !(torture_random(trsp) %
+			      (cxt.nrealwriters_stress * factor))) {
+			sched_set_fifo(current);
+		} else /* common case, do nothing */
+			return;
+	} else {
+		/*
+		 * The task will remain boosted for another ~500k operations,
+		 * then restored back to its original prio, and so forth.
+		 *
+		 * When @trsp is nil, we want to force-reset the task for
+		 * stopping the kthread.
+		 */
+		if (!trsp || !(torture_random(trsp) %
+			       (cxt.nrealwriters_stress * factor * 2))) {
+			sched_set_normal(current, 0);
+		} else /* common case, do nothing */
+			return;
+	}
+}
+
+static void torture_rtmutex_delay(struct torture_random_state *trsp)
+{
+	const unsigned long shortdelay_us = 2;
+	const unsigned long longdelay_ms = 100;
+
+	/*
+	 * We want a short delay mostly to emulate likely code, and
+	 * we want a long delay occasionally to force massive contention.
+	 */
+	if (!(torture_random(trsp) %
+	      (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+		mdelay(longdelay_ms);
+	if (!(torture_random(trsp) %
+	      (cxt.nrealwriters_stress * 2 * shortdelay_us)))
+		udelay(shortdelay_us);
+	if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
+		torture_preempt_schedule();  /* Allow test to be preempted. */
+}
+
+static void torture_rtmutex_unlock(int tid __maybe_unused)
+__releases(torture_rtmutex)
+{
+	rt_mutex_unlock(&torture_rtmutex);
+}
+
+static struct lock_torture_ops rtmutex_lock_ops = {
+	.writelock	= torture_rtmutex_lock,
+	.write_delay	= torture_rtmutex_delay,
+	.task_boost     = torture_rtmutex_boost,
+	.writeunlock	= torture_rtmutex_unlock,
+	.readlock       = NULL,
+	.read_delay     = NULL,
+	.readunlock     = NULL,
+	.name		= "rtmutex_lock"
+};
+#endif
+
+static DECLARE_RWSEM(torture_rwsem);
+static int torture_rwsem_down_write(int tid __maybe_unused)
+__acquires(torture_rwsem)
+{
+	down_write(&torture_rwsem);
+	return 0;
+}
+
+static void torture_rwsem_write_delay(struct torture_random_state *trsp)
+{
+	const unsigned long longdelay_ms = 100;
+
+	/* We want a long delay occasionally to force massive contention.  */
+	if (!(torture_random(trsp) %
+	      (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+		mdelay(longdelay_ms * 10);
+	else
+		mdelay(longdelay_ms / 10);
+	if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
+		torture_preempt_schedule();  /* Allow test to be preempted. */
+}
+
+static void torture_rwsem_up_write(int tid __maybe_unused)
+__releases(torture_rwsem)
+{
+	up_write(&torture_rwsem);
+}
+
+static int torture_rwsem_down_read(int tid __maybe_unused)
+__acquires(torture_rwsem)
+{
+	down_read(&torture_rwsem);
+	return 0;
+}
+
+static void torture_rwsem_read_delay(struct torture_random_state *trsp)
+{
+	const unsigned long longdelay_ms = 100;
+
+	/* We want a long delay occasionally to force massive contention.  */
+	if (!(torture_random(trsp) %
+	      (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
+		mdelay(longdelay_ms * 2);
+	else
+		mdelay(longdelay_ms / 2);
+	if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
+		torture_preempt_schedule();  /* Allow test to be preempted. */
+}
+
+static void torture_rwsem_up_read(int tid __maybe_unused)
+__releases(torture_rwsem)
+{
+	up_read(&torture_rwsem);
+}
+
+static struct lock_torture_ops rwsem_lock_ops = {
+	.writelock	= torture_rwsem_down_write,
+	.write_delay	= torture_rwsem_write_delay,
+	.task_boost     = torture_boost_dummy,
+	.writeunlock	= torture_rwsem_up_write,
+	.readlock       = torture_rwsem_down_read,
+	.read_delay     = torture_rwsem_read_delay,
+	.readunlock     = torture_rwsem_up_read,
+	.name		= "rwsem_lock"
+};
+
+#include <linux/percpu-rwsem.h>
+static struct percpu_rw_semaphore pcpu_rwsem;
+
+static void torture_percpu_rwsem_init(void)
+{
+	BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
+}
+
+static void torture_percpu_rwsem_exit(void)
+{
+	percpu_free_rwsem(&pcpu_rwsem);
+}
+
+static int torture_percpu_rwsem_down_write(int tid __maybe_unused)
+__acquires(pcpu_rwsem)
+{
+	percpu_down_write(&pcpu_rwsem);
+	return 0;
+}
+
+static void torture_percpu_rwsem_up_write(int tid __maybe_unused)
+__releases(pcpu_rwsem)
+{
+	percpu_up_write(&pcpu_rwsem);
+}
+
+static int torture_percpu_rwsem_down_read(int tid __maybe_unused)
+__acquires(pcpu_rwsem)
+{
+	percpu_down_read(&pcpu_rwsem);
+	return 0;
+}
+
+static void torture_percpu_rwsem_up_read(int tid __maybe_unused)
+__releases(pcpu_rwsem)
+{
+	percpu_up_read(&pcpu_rwsem);
+}
+
+static struct lock_torture_ops percpu_rwsem_lock_ops = {
+	.init		= torture_percpu_rwsem_init,
+	.exit		= torture_percpu_rwsem_exit,
+	.writelock	= torture_percpu_rwsem_down_write,
+	.write_delay	= torture_rwsem_write_delay,
+	.task_boost     = torture_boost_dummy,
+	.writeunlock	= torture_percpu_rwsem_up_write,
+	.readlock       = torture_percpu_rwsem_down_read,
+	.read_delay     = torture_rwsem_read_delay,
+	.readunlock     = torture_percpu_rwsem_up_read,
+	.name		= "percpu_rwsem_lock"
+};
+
+/*
+ * Lock torture writer kthread.  Repeatedly acquires and releases
+ * the lock, checking for duplicate acquisitions.
+ */
+static int lock_torture_writer(void *arg)
+{
+	struct lock_stress_stats *lwsp = arg;
+	int tid = lwsp - cxt.lwsa;
+	DEFINE_TORTURE_RANDOM(rand);
+
+	VERBOSE_TOROUT_STRING("lock_torture_writer task started");
+	set_user_nice(current, MAX_NICE);
+
+	do {
+		if ((torture_random(&rand) & 0xfffff) == 0)
+			schedule_timeout_uninterruptible(1);
+
+		cxt.cur_ops->task_boost(&rand);
+		cxt.cur_ops->writelock(tid);
+		if (WARN_ON_ONCE(lock_is_write_held))
+			lwsp->n_lock_fail++;
+		lock_is_write_held = true;
+		if (WARN_ON_ONCE(atomic_read(&lock_is_read_held)))
+			lwsp->n_lock_fail++; /* rare, but... */
+
+		lwsp->n_lock_acquired++;
+		cxt.cur_ops->write_delay(&rand);
+		lock_is_write_held = false;
+		WRITE_ONCE(last_lock_release, jiffies);
+		cxt.cur_ops->writeunlock(tid);
+
+		stutter_wait("lock_torture_writer");
+	} while (!torture_must_stop());
+
+	cxt.cur_ops->task_boost(NULL); /* reset prio */
+	torture_kthread_stopping("lock_torture_writer");
+	return 0;
+}
+
+/*
+ * Lock torture reader kthread.  Repeatedly acquires and releases
+ * the reader lock.
+ */
+static int lock_torture_reader(void *arg)
+{
+	struct lock_stress_stats *lrsp = arg;
+	int tid = lrsp - cxt.lrsa;
+	DEFINE_TORTURE_RANDOM(rand);
+
+	VERBOSE_TOROUT_STRING("lock_torture_reader task started");
+	set_user_nice(current, MAX_NICE);
+
+	do {
+		if ((torture_random(&rand) & 0xfffff) == 0)
+			schedule_timeout_uninterruptible(1);
+
+		cxt.cur_ops->readlock(tid);
+		atomic_inc(&lock_is_read_held);
+		if (WARN_ON_ONCE(lock_is_write_held))
+			lrsp->n_lock_fail++; /* rare, but... */
+
+		lrsp->n_lock_acquired++;
+		cxt.cur_ops->read_delay(&rand);
+		atomic_dec(&lock_is_read_held);
+		cxt.cur_ops->readunlock(tid);
+
+		stutter_wait("lock_torture_reader");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("lock_torture_reader");
+	return 0;
+}
+
+/*
+ * Create an lock-torture-statistics message in the specified buffer.
+ */
+static void __torture_print_stats(char *page,
+				  struct lock_stress_stats *statp, bool write)
+{
+	long cur;
+	bool fail = false;
+	int i, n_stress;
+	long max = 0, min = statp ? data_race(statp[0].n_lock_acquired) : 0;
+	long long sum = 0;
+
+	n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
+	for (i = 0; i < n_stress; i++) {
+		if (data_race(statp[i].n_lock_fail))
+			fail = true;
+		cur = data_race(statp[i].n_lock_acquired);
+		sum += cur;
+		if (max < cur)
+			max = cur;
+		if (min > cur)
+			min = cur;
+	}
+	page += sprintf(page,
+			"%s:  Total: %lld  Max/Min: %ld/%ld %s  Fail: %d %s\n",
+			write ? "Writes" : "Reads ",
+			sum, max, min,
+			!onoff_interval && max / 2 > min ? "???" : "",
+			fail, fail ? "!!!" : "");
+	if (fail)
+		atomic_inc(&cxt.n_lock_torture_errors);
+}
+
+/*
+ * Print torture statistics.  Caller must ensure that there is only one
+ * call to this function at a given time!!!  This is normally accomplished
+ * by relying on the module system to only have one copy of the module
+ * loaded, and then by giving the lock_torture_stats kthread full control
+ * (or the init/cleanup functions when lock_torture_stats thread is not
+ * running).
+ */
+static void lock_torture_stats_print(void)
+{
+	int size = cxt.nrealwriters_stress * 200 + 8192;
+	char *buf;
+
+	if (cxt.cur_ops->readlock)
+		size += cxt.nrealreaders_stress * 200 + 8192;
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf) {
+		pr_err("lock_torture_stats_print: Out of memory, need: %d",
+		       size);
+		return;
+	}
+
+	__torture_print_stats(buf, cxt.lwsa, true);
+	pr_alert("%s", buf);
+	kfree(buf);
+
+	if (cxt.cur_ops->readlock) {
+		buf = kmalloc(size, GFP_KERNEL);
+		if (!buf) {
+			pr_err("lock_torture_stats_print: Out of memory, need: %d",
+			       size);
+			return;
+		}
+
+		__torture_print_stats(buf, cxt.lrsa, false);
+		pr_alert("%s", buf);
+		kfree(buf);
+	}
+}
+
+/*
+ * Periodically prints torture statistics, if periodic statistics printing
+ * was specified via the stat_interval module parameter.
+ *
+ * No need to worry about fullstop here, since this one doesn't reference
+ * volatile state or register callbacks.
+ */
+static int lock_torture_stats(void *arg)
+{
+	VERBOSE_TOROUT_STRING("lock_torture_stats task started");
+	do {
+		schedule_timeout_interruptible(stat_interval * HZ);
+		lock_torture_stats_print();
+		torture_shutdown_absorb("lock_torture_stats");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("lock_torture_stats");
+	return 0;
+}
+
+static inline void
+lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
+				const char *tag)
+{
+	pr_alert("%s" TORTURE_FLAG
+		 "--- %s%s: nwriters_stress=%d nreaders_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
+		 torture_type, tag, cxt.debug_lock ? " [debug]": "",
+		 cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
+		 verbose, shuffle_interval, stutter, shutdown_secs,
+		 onoff_interval, onoff_holdoff);
+}
+
+static void lock_torture_cleanup(void)
+{
+	int i;
+
+	if (torture_cleanup_begin())
+		return;
+
+	/*
+	 * Indicates early cleanup, meaning that the test has not run,
+	 * such as when passing bogus args when loading the module.
+	 * However cxt->cur_ops.init() may have been invoked, so beside
+	 * perform the underlying torture-specific cleanups, cur_ops.exit()
+	 * will be invoked if needed.
+	 */
+	if (!cxt.lwsa && !cxt.lrsa)
+		goto end;
+
+	if (writer_tasks) {
+		for (i = 0; i < cxt.nrealwriters_stress; i++)
+			torture_stop_kthread(lock_torture_writer,
+					     writer_tasks[i]);
+		kfree(writer_tasks);
+		writer_tasks = NULL;
+	}
+
+	if (reader_tasks) {
+		for (i = 0; i < cxt.nrealreaders_stress; i++)
+			torture_stop_kthread(lock_torture_reader,
+					     reader_tasks[i]);
+		kfree(reader_tasks);
+		reader_tasks = NULL;
+	}
+
+	torture_stop_kthread(lock_torture_stats, stats_task);
+	lock_torture_stats_print();  /* -After- the stats thread is stopped! */
+
+	if (atomic_read(&cxt.n_lock_torture_errors))
+		lock_torture_print_module_parms(cxt.cur_ops,
+						"End of test: FAILURE");
+	else if (torture_onoff_failures())
+		lock_torture_print_module_parms(cxt.cur_ops,
+						"End of test: LOCK_HOTPLUG");
+	else
+		lock_torture_print_module_parms(cxt.cur_ops,
+						"End of test: SUCCESS");
+
+	kfree(cxt.lwsa);
+	cxt.lwsa = NULL;
+	kfree(cxt.lrsa);
+	cxt.lrsa = NULL;
+
+end:
+	if (cxt.init_called) {
+		if (cxt.cur_ops->exit)
+			cxt.cur_ops->exit();
+		cxt.init_called = false;
+	}
+	torture_cleanup_end();
+}
+
+static int __init lock_torture_init(void)
+{
+	int i, j;
+	int firsterr = 0;
+	static struct lock_torture_ops *torture_ops[] = {
+		&lock_busted_ops,
+		&spin_lock_ops, &spin_lock_irq_ops,
+		&rw_lock_ops, &rw_lock_irq_ops,
+		&mutex_lock_ops,
+		&ww_mutex_lock_ops,
+#ifdef CONFIG_RT_MUTEXES
+		&rtmutex_lock_ops,
+#endif
+		&rwsem_lock_ops,
+		&percpu_rwsem_lock_ops,
+	};
+
+	if (!torture_init_begin(torture_type, verbose))
+		return -EBUSY;
+
+	/* Process args and tell the world that the torturer is on the job. */
+	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
+		cxt.cur_ops = torture_ops[i];
+		if (strcmp(torture_type, cxt.cur_ops->name) == 0)
+			break;
+	}
+	if (i == ARRAY_SIZE(torture_ops)) {
+		pr_alert("lock-torture: invalid torture type: \"%s\"\n",
+			 torture_type);
+		pr_alert("lock-torture types:");
+		for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
+			pr_alert(" %s", torture_ops[i]->name);
+		pr_alert("\n");
+		firsterr = -EINVAL;
+		goto unwind;
+	}
+
+	if (nwriters_stress == 0 &&
+	    (!cxt.cur_ops->readlock || nreaders_stress == 0)) {
+		pr_alert("lock-torture: must run at least one locking thread\n");
+		firsterr = -EINVAL;
+		goto unwind;
+	}
+
+	if (nwriters_stress >= 0)
+		cxt.nrealwriters_stress = nwriters_stress;
+	else
+		cxt.nrealwriters_stress = 2 * num_online_cpus();
+
+	if (cxt.cur_ops->init) {
+		cxt.cur_ops->init();
+		cxt.init_called = true;
+	}
+
+#ifdef CONFIG_DEBUG_MUTEXES
+	if (str_has_prefix(torture_type, "mutex"))
+		cxt.debug_lock = true;
+#endif
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+	if (str_has_prefix(torture_type, "rtmutex"))
+		cxt.debug_lock = true;
+#endif
+#ifdef CONFIG_DEBUG_SPINLOCK
+	if ((str_has_prefix(torture_type, "spin")) ||
+	    (str_has_prefix(torture_type, "rw_lock")))
+		cxt.debug_lock = true;
+#endif
+
+	/* Initialize the statistics so that each run gets its own numbers. */
+	if (nwriters_stress) {
+		lock_is_write_held = false;
+		cxt.lwsa = kmalloc_array(cxt.nrealwriters_stress,
+					 sizeof(*cxt.lwsa),
+					 GFP_KERNEL);
+		if (cxt.lwsa == NULL) {
+			VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
+			firsterr = -ENOMEM;
+			goto unwind;
+		}
+
+		for (i = 0; i < cxt.nrealwriters_stress; i++) {
+			cxt.lwsa[i].n_lock_fail = 0;
+			cxt.lwsa[i].n_lock_acquired = 0;
+		}
+	}
+
+	if (cxt.cur_ops->readlock) {
+		if (nreaders_stress >= 0)
+			cxt.nrealreaders_stress = nreaders_stress;
+		else {
+			/*
+			 * By default distribute evenly the number of
+			 * readers and writers. We still run the same number
+			 * of threads as the writer-only locks default.
+			 */
+			if (nwriters_stress < 0) /* user doesn't care */
+				cxt.nrealwriters_stress = num_online_cpus();
+			cxt.nrealreaders_stress = cxt.nrealwriters_stress;
+		}
+
+		if (nreaders_stress) {
+			cxt.lrsa = kmalloc_array(cxt.nrealreaders_stress,
+						 sizeof(*cxt.lrsa),
+						 GFP_KERNEL);
+			if (cxt.lrsa == NULL) {
+				VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
+				firsterr = -ENOMEM;
+				kfree(cxt.lwsa);
+				cxt.lwsa = NULL;
+				goto unwind;
+			}
+
+			for (i = 0; i < cxt.nrealreaders_stress; i++) {
+				cxt.lrsa[i].n_lock_fail = 0;
+				cxt.lrsa[i].n_lock_acquired = 0;
+			}
+		}
+	}
+
+	lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
+
+	/* Prepare torture context. */
+	if (onoff_interval > 0) {
+		firsterr = torture_onoff_init(onoff_holdoff * HZ,
+					      onoff_interval * HZ, NULL);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	if (shuffle_interval > 0) {
+		firsterr = torture_shuffle_init(shuffle_interval);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	if (shutdown_secs > 0) {
+		firsterr = torture_shutdown_init(shutdown_secs,
+						 lock_torture_cleanup);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	if (stutter > 0) {
+		firsterr = torture_stutter_init(stutter, stutter);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+
+	if (nwriters_stress) {
+		writer_tasks = kcalloc(cxt.nrealwriters_stress,
+				       sizeof(writer_tasks[0]),
+				       GFP_KERNEL);
+		if (writer_tasks == NULL) {
+			TOROUT_ERRSTRING("writer_tasks: Out of memory");
+			firsterr = -ENOMEM;
+			goto unwind;
+		}
+	}
+
+	if (cxt.cur_ops->readlock) {
+		reader_tasks = kcalloc(cxt.nrealreaders_stress,
+				       sizeof(reader_tasks[0]),
+				       GFP_KERNEL);
+		if (reader_tasks == NULL) {
+			TOROUT_ERRSTRING("reader_tasks: Out of memory");
+			kfree(writer_tasks);
+			writer_tasks = NULL;
+			firsterr = -ENOMEM;
+			goto unwind;
+		}
+	}
+
+	/*
+	 * Create the kthreads and start torturing (oh, those poor little locks).
+	 *
+	 * TODO: Note that we interleave writers with readers, giving writers a
+	 * slight advantage, by creating its kthread first. This can be modified
+	 * for very specific needs, or even let the user choose the policy, if
+	 * ever wanted.
+	 */
+	for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
+		    j < cxt.nrealreaders_stress; i++, j++) {
+		if (i >= cxt.nrealwriters_stress)
+			goto create_reader;
+
+		/* Create writer. */
+		firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
+						  writer_tasks[i]);
+		if (torture_init_error(firsterr))
+			goto unwind;
+
+	create_reader:
+		if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
+			continue;
+		/* Create reader. */
+		firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
+						  reader_tasks[j]);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	if (stat_interval > 0) {
+		firsterr = torture_create_kthread(lock_torture_stats, NULL,
+						  stats_task);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	torture_init_end();
+	return 0;
+
+unwind:
+	torture_init_end();
+	lock_torture_cleanup();
+	if (shutdown_secs) {
+		WARN_ON(!IS_MODULE(CONFIG_LOCK_TORTURE_TEST));
+		kernel_power_off();
+	}
+	return firsterr;
+}
+
+module_init(lock_torture_init);
+module_exit(lock_torture_cleanup);
diff --git a/kernel/locking/mcs_spinlock.h b/kernel/locking/mcs_spinlock.h
new file mode 100644
index 000000000..85251d877
--- /dev/null
+++ b/kernel/locking/mcs_spinlock.h
@@ -0,0 +1,121 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * MCS lock defines
+ *
+ * This file contains the main data structure and API definitions of MCS lock.
+ *
+ * The MCS lock (proposed by Mellor-Crummey and Scott) is a simple spin-lock
+ * with the desirable properties of being fair, and with each cpu trying
+ * to acquire the lock spinning on a local variable.
+ * It avoids expensive cache bounces that common test-and-set spin-lock
+ * implementations incur.
+ */
+#ifndef __LINUX_MCS_SPINLOCK_H
+#define __LINUX_MCS_SPINLOCK_H
+
+#include <asm/mcs_spinlock.h>
+
+struct mcs_spinlock {
+	struct mcs_spinlock *next;
+	int locked; /* 1 if lock acquired */
+	int count;  /* nesting count, see qspinlock.c */
+};
+
+#ifndef arch_mcs_spin_lock_contended
+/*
+ * Using smp_cond_load_acquire() provides the acquire semantics
+ * required so that subsequent operations happen after the
+ * lock is acquired. Additionally, some architectures such as
+ * ARM64 would like to do spin-waiting instead of purely
+ * spinning, and smp_cond_load_acquire() provides that behavior.
+ */
+#define arch_mcs_spin_lock_contended(l)					\
+do {									\
+	smp_cond_load_acquire(l, VAL);					\
+} while (0)
+#endif
+
+#ifndef arch_mcs_spin_unlock_contended
+/*
+ * smp_store_release() provides a memory barrier to ensure all
+ * operations in the critical section has been completed before
+ * unlocking.
+ */
+#define arch_mcs_spin_unlock_contended(l)				\
+	smp_store_release((l), 1)
+#endif
+
+/*
+ * Note: the smp_load_acquire/smp_store_release pair is not
+ * sufficient to form a full memory barrier across
+ * cpus for many architectures (except x86) for mcs_unlock and mcs_lock.
+ * For applications that need a full barrier across multiple cpus
+ * with mcs_unlock and mcs_lock pair, smp_mb__after_unlock_lock() should be
+ * used after mcs_lock.
+ */
+
+/*
+ * In order to acquire the lock, the caller should declare a local node and
+ * pass a reference of the node to this function in addition to the lock.
+ * If the lock has already been acquired, then this will proceed to spin
+ * on this node->locked until the previous lock holder sets the node->locked
+ * in mcs_spin_unlock().
+ */
+static inline
+void mcs_spin_lock(struct mcs_spinlock **lock, struct mcs_spinlock *node)
+{
+	struct mcs_spinlock *prev;
+
+	/* Init node */
+	node->locked = 0;
+	node->next   = NULL;
+
+	/*
+	 * We rely on the full barrier with global transitivity implied by the
+	 * below xchg() to order the initialization stores above against any
+	 * observation of @node. And to provide the ACQUIRE ordering associated
+	 * with a LOCK primitive.
+	 */
+	prev = xchg(lock, node);
+	if (likely(prev == NULL)) {
+		/*
+		 * Lock acquired, don't need to set node->locked to 1. Threads
+		 * only spin on its own node->locked value for lock acquisition.
+		 * However, since this thread can immediately acquire the lock
+		 * and does not proceed to spin on its own node->locked, this
+		 * value won't be used. If a debug mode is needed to
+		 * audit lock status, then set node->locked value here.
+		 */
+		return;
+	}
+	WRITE_ONCE(prev->next, node);
+
+	/* Wait until the lock holder passes the lock down. */
+	arch_mcs_spin_lock_contended(&node->locked);
+}
+
+/*
+ * Releases the lock. The caller should pass in the corresponding node that
+ * was used to acquire the lock.
+ */
+static inline
+void mcs_spin_unlock(struct mcs_spinlock **lock, struct mcs_spinlock *node)
+{
+	struct mcs_spinlock *next = READ_ONCE(node->next);
+
+	if (likely(!next)) {
+		/*
+		 * Release the lock by setting it to NULL
+		 */
+		if (likely(cmpxchg_release(lock, node, NULL) == node))
+			return;
+		/* Wait until the next pointer is set */
+		while (!(next = READ_ONCE(node->next)))
+			cpu_relax();
+	}
+
+	/* Pass lock to next waiter. */
+	arch_mcs_spin_unlock_contended(&next->locked);
+}
+
+#endif /* __LINUX_MCS_SPINLOCK_H */
diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
new file mode 100644
index 000000000..bc8abb854
--- /dev/null
+++ b/kernel/locking/mutex-debug.c
@@ -0,0 +1,106 @@
+/*
+ * Debugging code for mutexes
+ *
+ * Started by Ingo Molnar:
+ *
+ *  Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * lock debugging, locking tree, deadlock detection started by:
+ *
+ *  Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
+ *  Released under the General Public License (GPL).
+ */
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/poison.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/interrupt.h>
+#include <linux/debug_locks.h>
+
+#include "mutex.h"
+
+/*
+ * Must be called with lock->wait_lock held.
+ */
+void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
+{
+	memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
+	waiter->magic = waiter;
+	INIT_LIST_HEAD(&waiter->list);
+	waiter->ww_ctx = MUTEX_POISON_WW_CTX;
+}
+
+void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
+{
+	lockdep_assert_held(&lock->wait_lock);
+	DEBUG_LOCKS_WARN_ON(list_empty(&lock->wait_list));
+	DEBUG_LOCKS_WARN_ON(waiter->magic != waiter);
+	DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
+}
+
+void debug_mutex_free_waiter(struct mutex_waiter *waiter)
+{
+	DEBUG_LOCKS_WARN_ON(!list_empty(&waiter->list));
+	memset(waiter, MUTEX_DEBUG_FREE, sizeof(*waiter));
+}
+
+void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+			    struct task_struct *task)
+{
+	lockdep_assert_held(&lock->wait_lock);
+
+	/* Mark the current thread as blocked on the lock: */
+	task->blocked_on = waiter;
+}
+
+void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+			 struct task_struct *task)
+{
+	DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
+	DEBUG_LOCKS_WARN_ON(waiter->task != task);
+	DEBUG_LOCKS_WARN_ON(task->blocked_on != waiter);
+	task->blocked_on = NULL;
+
+	INIT_LIST_HEAD(&waiter->list);
+	waiter->task = NULL;
+}
+
+void debug_mutex_unlock(struct mutex *lock)
+{
+	if (likely(debug_locks)) {
+		DEBUG_LOCKS_WARN_ON(lock->magic != lock);
+		DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
+	}
+}
+
+void debug_mutex_init(struct mutex *lock, const char *name,
+		      struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held lock:
+	 */
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_SLEEP);
+#endif
+	lock->magic = lock;
+}
+
+/***
+ * mutex_destroy - mark a mutex unusable
+ * @lock: the mutex to be destroyed
+ *
+ * This function marks the mutex uninitialized, and any subsequent
+ * use of the mutex is forbidden. The mutex must not be locked when
+ * this function is called.
+ */
+void mutex_destroy(struct mutex *lock)
+{
+	DEBUG_LOCKS_WARN_ON(mutex_is_locked(lock));
+	lock->magic = NULL;
+}
+
+EXPORT_SYMBOL_GPL(mutex_destroy);
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
new file mode 100644
index 000000000..d973fe604
--- /dev/null
+++ b/kernel/locking/mutex.c
@@ -0,0 +1,1151 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/locking/mutex.c
+ *
+ * Mutexes: blocking mutual exclusion locks
+ *
+ * Started by Ingo Molnar:
+ *
+ *  Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * Many thanks to Arjan van de Ven, Thomas Gleixner, Steven Rostedt and
+ * David Howells for suggestions and improvements.
+ *
+ *  - Adaptive spinning for mutexes by Peter Zijlstra. (Ported to mainline
+ *    from the -rt tree, where it was originally implemented for rtmutexes
+ *    by Steven Rostedt, based on work by Gregory Haskins, Peter Morreale
+ *    and Sven Dietrich.
+ *
+ * Also see Documentation/locking/mutex-design.rst.
+ */
+#include <linux/mutex.h>
+#include <linux/ww_mutex.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/rt.h>
+#include <linux/sched/wake_q.h>
+#include <linux/sched/debug.h>
+#include <linux/export.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/debug_locks.h>
+#include <linux/osq_lock.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/lock.h>
+
+#ifndef CONFIG_PREEMPT_RT
+#include "mutex.h"
+
+#ifdef CONFIG_DEBUG_MUTEXES
+# define MUTEX_WARN_ON(cond) DEBUG_LOCKS_WARN_ON(cond)
+#else
+# define MUTEX_WARN_ON(cond)
+#endif
+
+void
+__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
+{
+	atomic_long_set(&lock->owner, 0);
+	raw_spin_lock_init(&lock->wait_lock);
+	INIT_LIST_HEAD(&lock->wait_list);
+#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
+	osq_lock_init(&lock->osq);
+#endif
+
+	debug_mutex_init(lock, name, key);
+}
+EXPORT_SYMBOL(__mutex_init);
+
+/*
+ * @owner: contains: 'struct task_struct *' to the current lock owner,
+ * NULL means not owned. Since task_struct pointers are aligned at
+ * at least L1_CACHE_BYTES, we have low bits to store extra state.
+ *
+ * Bit0 indicates a non-empty waiter list; unlock must issue a wakeup.
+ * Bit1 indicates unlock needs to hand the lock to the top-waiter
+ * Bit2 indicates handoff has been done and we're waiting for pickup.
+ */
+#define MUTEX_FLAG_WAITERS	0x01
+#define MUTEX_FLAG_HANDOFF	0x02
+#define MUTEX_FLAG_PICKUP	0x04
+
+#define MUTEX_FLAGS		0x07
+
+/*
+ * Internal helper function; C doesn't allow us to hide it :/
+ *
+ * DO NOT USE (outside of mutex code).
+ */
+static inline struct task_struct *__mutex_owner(struct mutex *lock)
+{
+	return (struct task_struct *)(atomic_long_read(&lock->owner) & ~MUTEX_FLAGS);
+}
+
+static inline struct task_struct *__owner_task(unsigned long owner)
+{
+	return (struct task_struct *)(owner & ~MUTEX_FLAGS);
+}
+
+bool mutex_is_locked(struct mutex *lock)
+{
+	return __mutex_owner(lock) != NULL;
+}
+EXPORT_SYMBOL(mutex_is_locked);
+
+static inline unsigned long __owner_flags(unsigned long owner)
+{
+	return owner & MUTEX_FLAGS;
+}
+
+/*
+ * Returns: __mutex_owner(lock) on failure or NULL on success.
+ */
+static inline struct task_struct *__mutex_trylock_common(struct mutex *lock, bool handoff)
+{
+	unsigned long owner, curr = (unsigned long)current;
+
+	owner = atomic_long_read(&lock->owner);
+	for (;;) { /* must loop, can race against a flag */
+		unsigned long flags = __owner_flags(owner);
+		unsigned long task = owner & ~MUTEX_FLAGS;
+
+		if (task) {
+			if (flags & MUTEX_FLAG_PICKUP) {
+				if (task != curr)
+					break;
+				flags &= ~MUTEX_FLAG_PICKUP;
+			} else if (handoff) {
+				if (flags & MUTEX_FLAG_HANDOFF)
+					break;
+				flags |= MUTEX_FLAG_HANDOFF;
+			} else {
+				break;
+			}
+		} else {
+			MUTEX_WARN_ON(flags & (MUTEX_FLAG_HANDOFF | MUTEX_FLAG_PICKUP));
+			task = curr;
+		}
+
+		if (atomic_long_try_cmpxchg_acquire(&lock->owner, &owner, task | flags)) {
+			if (task == curr)
+				return NULL;
+			break;
+		}
+	}
+
+	return __owner_task(owner);
+}
+
+/*
+ * Trylock or set HANDOFF
+ */
+static inline bool __mutex_trylock_or_handoff(struct mutex *lock, bool handoff)
+{
+	return !__mutex_trylock_common(lock, handoff);
+}
+
+/*
+ * Actual trylock that will work on any unlocked state.
+ */
+static inline bool __mutex_trylock(struct mutex *lock)
+{
+	return !__mutex_trylock_common(lock, false);
+}
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+/*
+ * Lockdep annotations are contained to the slow paths for simplicity.
+ * There is nothing that would stop spreading the lockdep annotations outwards
+ * except more code.
+ */
+
+/*
+ * Optimistic trylock that only works in the uncontended case. Make sure to
+ * follow with a __mutex_trylock() before failing.
+ */
+static __always_inline bool __mutex_trylock_fast(struct mutex *lock)
+{
+	unsigned long curr = (unsigned long)current;
+	unsigned long zero = 0UL;
+
+	if (atomic_long_try_cmpxchg_acquire(&lock->owner, &zero, curr))
+		return true;
+
+	return false;
+}
+
+static __always_inline bool __mutex_unlock_fast(struct mutex *lock)
+{
+	unsigned long curr = (unsigned long)current;
+
+	return atomic_long_try_cmpxchg_release(&lock->owner, &curr, 0UL);
+}
+#endif
+
+static inline void __mutex_set_flag(struct mutex *lock, unsigned long flag)
+{
+	atomic_long_or(flag, &lock->owner);
+}
+
+static inline void __mutex_clear_flag(struct mutex *lock, unsigned long flag)
+{
+	atomic_long_andnot(flag, &lock->owner);
+}
+
+static inline bool __mutex_waiter_is_first(struct mutex *lock, struct mutex_waiter *waiter)
+{
+	return list_first_entry(&lock->wait_list, struct mutex_waiter, list) == waiter;
+}
+
+/*
+ * Add @waiter to a given location in the lock wait_list and set the
+ * FLAG_WAITERS flag if it's the first waiter.
+ */
+static void
+__mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+		   struct list_head *list)
+{
+	debug_mutex_add_waiter(lock, waiter, current);
+
+	list_add_tail(&waiter->list, list);
+	if (__mutex_waiter_is_first(lock, waiter))
+		__mutex_set_flag(lock, MUTEX_FLAG_WAITERS);
+}
+
+static void
+__mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter)
+{
+	list_del(&waiter->list);
+	if (likely(list_empty(&lock->wait_list)))
+		__mutex_clear_flag(lock, MUTEX_FLAGS);
+
+	debug_mutex_remove_waiter(lock, waiter, current);
+}
+
+/*
+ * Give up ownership to a specific task, when @task = NULL, this is equivalent
+ * to a regular unlock. Sets PICKUP on a handoff, clears HANDOFF, preserves
+ * WAITERS. Provides RELEASE semantics like a regular unlock, the
+ * __mutex_trylock() provides a matching ACQUIRE semantics for the handoff.
+ */
+static void __mutex_handoff(struct mutex *lock, struct task_struct *task)
+{
+	unsigned long owner = atomic_long_read(&lock->owner);
+
+	for (;;) {
+		unsigned long new;
+
+		MUTEX_WARN_ON(__owner_task(owner) != current);
+		MUTEX_WARN_ON(owner & MUTEX_FLAG_PICKUP);
+
+		new = (owner & MUTEX_FLAG_WAITERS);
+		new |= (unsigned long)task;
+		if (task)
+			new |= MUTEX_FLAG_PICKUP;
+
+		if (atomic_long_try_cmpxchg_release(&lock->owner, &owner, new))
+			break;
+	}
+}
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+/*
+ * We split the mutex lock/unlock logic into separate fastpath and
+ * slowpath functions, to reduce the register pressure on the fastpath.
+ * We also put the fastpath first in the kernel image, to make sure the
+ * branch is predicted by the CPU as default-untaken.
+ */
+static void __sched __mutex_lock_slowpath(struct mutex *lock);
+
+/**
+ * mutex_lock - acquire the mutex
+ * @lock: the mutex to be acquired
+ *
+ * Lock the mutex exclusively for this task. If the mutex is not
+ * available right now, it will sleep until it can get it.
+ *
+ * The mutex must later on be released by the same task that
+ * acquired it. Recursive locking is not allowed. The task
+ * may not exit without first unlocking the mutex. Also, kernel
+ * memory where the mutex resides must not be freed with
+ * the mutex still locked. The mutex must first be initialized
+ * (or statically defined) before it can be locked. memset()-ing
+ * the mutex to 0 is not allowed.
+ *
+ * (The CONFIG_DEBUG_MUTEXES .config option turns on debugging
+ * checks that will enforce the restrictions and will also do
+ * deadlock debugging)
+ *
+ * This function is similar to (but not equivalent to) down().
+ */
+void __sched mutex_lock(struct mutex *lock)
+{
+	might_sleep();
+
+	if (!__mutex_trylock_fast(lock))
+		__mutex_lock_slowpath(lock);
+}
+EXPORT_SYMBOL(mutex_lock);
+#endif
+
+#include "ww_mutex.h"
+
+#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
+
+/*
+ * Trylock variant that returns the owning task on failure.
+ */
+static inline struct task_struct *__mutex_trylock_or_owner(struct mutex *lock)
+{
+	return __mutex_trylock_common(lock, false);
+}
+
+static inline
+bool ww_mutex_spin_on_owner(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
+			    struct mutex_waiter *waiter)
+{
+	struct ww_mutex *ww;
+
+	ww = container_of(lock, struct ww_mutex, base);
+
+	/*
+	 * If ww->ctx is set the contents are undefined, only
+	 * by acquiring wait_lock there is a guarantee that
+	 * they are not invalid when reading.
+	 *
+	 * As such, when deadlock detection needs to be
+	 * performed the optimistic spinning cannot be done.
+	 *
+	 * Check this in every inner iteration because we may
+	 * be racing against another thread's ww_mutex_lock.
+	 */
+	if (ww_ctx->acquired > 0 && READ_ONCE(ww->ctx))
+		return false;
+
+	/*
+	 * If we aren't on the wait list yet, cancel the spin
+	 * if there are waiters. We want  to avoid stealing the
+	 * lock from a waiter with an earlier stamp, since the
+	 * other thread may already own a lock that we also
+	 * need.
+	 */
+	if (!waiter && (atomic_long_read(&lock->owner) & MUTEX_FLAG_WAITERS))
+		return false;
+
+	/*
+	 * Similarly, stop spinning if we are no longer the
+	 * first waiter.
+	 */
+	if (waiter && !__mutex_waiter_is_first(lock, waiter))
+		return false;
+
+	return true;
+}
+
+/*
+ * Look out! "owner" is an entirely speculative pointer access and not
+ * reliable.
+ *
+ * "noinline" so that this function shows up on perf profiles.
+ */
+static noinline
+bool mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner,
+			 struct ww_acquire_ctx *ww_ctx, struct mutex_waiter *waiter)
+{
+	bool ret = true;
+
+	lockdep_assert_preemption_disabled();
+
+	while (__mutex_owner(lock) == owner) {
+		/*
+		 * Ensure we emit the owner->on_cpu, dereference _after_
+		 * checking lock->owner still matches owner. And we already
+		 * disabled preemption which is equal to the RCU read-side
+		 * crital section in optimistic spinning code. Thus the
+		 * task_strcut structure won't go away during the spinning
+		 * period
+		 */
+		barrier();
+
+		/*
+		 * Use vcpu_is_preempted to detect lock holder preemption issue.
+		 */
+		if (!owner_on_cpu(owner) || need_resched()) {
+			ret = false;
+			break;
+		}
+
+		if (ww_ctx && !ww_mutex_spin_on_owner(lock, ww_ctx, waiter)) {
+			ret = false;
+			break;
+		}
+
+		cpu_relax();
+	}
+
+	return ret;
+}
+
+/*
+ * Initial check for entering the mutex spinning loop
+ */
+static inline int mutex_can_spin_on_owner(struct mutex *lock)
+{
+	struct task_struct *owner;
+	int retval = 1;
+
+	lockdep_assert_preemption_disabled();
+
+	if (need_resched())
+		return 0;
+
+	/*
+	 * We already disabled preemption which is equal to the RCU read-side
+	 * crital section in optimistic spinning code. Thus the task_strcut
+	 * structure won't go away during the spinning period.
+	 */
+	owner = __mutex_owner(lock);
+	if (owner)
+		retval = owner_on_cpu(owner);
+
+	/*
+	 * If lock->owner is not set, the mutex has been released. Return true
+	 * such that we'll trylock in the spin path, which is a faster option
+	 * than the blocking slow path.
+	 */
+	return retval;
+}
+
+/*
+ * Optimistic spinning.
+ *
+ * We try to spin for acquisition when we find that the lock owner
+ * is currently running on a (different) CPU and while we don't
+ * need to reschedule. The rationale is that if the lock owner is
+ * running, it is likely to release the lock soon.
+ *
+ * The mutex spinners are queued up using MCS lock so that only one
+ * spinner can compete for the mutex. However, if mutex spinning isn't
+ * going to happen, there is no point in going through the lock/unlock
+ * overhead.
+ *
+ * Returns true when the lock was taken, otherwise false, indicating
+ * that we need to jump to the slowpath and sleep.
+ *
+ * The waiter flag is set to true if the spinner is a waiter in the wait
+ * queue. The waiter-spinner will spin on the lock directly and concurrently
+ * with the spinner at the head of the OSQ, if present, until the owner is
+ * changed to itself.
+ */
+static __always_inline bool
+mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
+		      struct mutex_waiter *waiter)
+{
+	if (!waiter) {
+		/*
+		 * The purpose of the mutex_can_spin_on_owner() function is
+		 * to eliminate the overhead of osq_lock() and osq_unlock()
+		 * in case spinning isn't possible. As a waiter-spinner
+		 * is not going to take OSQ lock anyway, there is no need
+		 * to call mutex_can_spin_on_owner().
+		 */
+		if (!mutex_can_spin_on_owner(lock))
+			goto fail;
+
+		/*
+		 * In order to avoid a stampede of mutex spinners trying to
+		 * acquire the mutex all at once, the spinners need to take a
+		 * MCS (queued) lock first before spinning on the owner field.
+		 */
+		if (!osq_lock(&lock->osq))
+			goto fail;
+	}
+
+	for (;;) {
+		struct task_struct *owner;
+
+		/* Try to acquire the mutex... */
+		owner = __mutex_trylock_or_owner(lock);
+		if (!owner)
+			break;
+
+		/*
+		 * There's an owner, wait for it to either
+		 * release the lock or go to sleep.
+		 */
+		if (!mutex_spin_on_owner(lock, owner, ww_ctx, waiter))
+			goto fail_unlock;
+
+		/*
+		 * The cpu_relax() call is a compiler barrier which forces
+		 * everything in this loop to be re-loaded. We don't need
+		 * memory barriers as we'll eventually observe the right
+		 * values at the cost of a few extra spins.
+		 */
+		cpu_relax();
+	}
+
+	if (!waiter)
+		osq_unlock(&lock->osq);
+
+	return true;
+
+
+fail_unlock:
+	if (!waiter)
+		osq_unlock(&lock->osq);
+
+fail:
+	/*
+	 * If we fell out of the spin path because of need_resched(),
+	 * reschedule now, before we try-lock the mutex. This avoids getting
+	 * scheduled out right after we obtained the mutex.
+	 */
+	if (need_resched()) {
+		/*
+		 * We _should_ have TASK_RUNNING here, but just in case
+		 * we do not, make it so, otherwise we might get stuck.
+		 */
+		__set_current_state(TASK_RUNNING);
+		schedule_preempt_disabled();
+	}
+
+	return false;
+}
+#else
+static __always_inline bool
+mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
+		      struct mutex_waiter *waiter)
+{
+	return false;
+}
+#endif
+
+static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigned long ip);
+
+/**
+ * mutex_unlock - release the mutex
+ * @lock: the mutex to be released
+ *
+ * Unlock a mutex that has been locked by this task previously.
+ *
+ * This function must not be used in interrupt context. Unlocking
+ * of a not locked mutex is not allowed.
+ *
+ * This function is similar to (but not equivalent to) up().
+ */
+void __sched mutex_unlock(struct mutex *lock)
+{
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+	if (__mutex_unlock_fast(lock))
+		return;
+#endif
+	__mutex_unlock_slowpath(lock, _RET_IP_);
+}
+EXPORT_SYMBOL(mutex_unlock);
+
+/**
+ * ww_mutex_unlock - release the w/w mutex
+ * @lock: the mutex to be released
+ *
+ * Unlock a mutex that has been locked by this task previously with any of the
+ * ww_mutex_lock* functions (with or without an acquire context). It is
+ * forbidden to release the locks after releasing the acquire context.
+ *
+ * This function must not be used in interrupt context. Unlocking
+ * of a unlocked mutex is not allowed.
+ */
+void __sched ww_mutex_unlock(struct ww_mutex *lock)
+{
+	__ww_mutex_unlock(lock);
+	mutex_unlock(&lock->base);
+}
+EXPORT_SYMBOL(ww_mutex_unlock);
+
+/*
+ * Lock a mutex (possibly interruptible), slowpath:
+ */
+static __always_inline int __sched
+__mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclass,
+		    struct lockdep_map *nest_lock, unsigned long ip,
+		    struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx)
+{
+	struct mutex_waiter waiter;
+	struct ww_mutex *ww;
+	int ret;
+
+	if (!use_ww_ctx)
+		ww_ctx = NULL;
+
+	might_sleep();
+
+	MUTEX_WARN_ON(lock->magic != lock);
+
+	ww = container_of(lock, struct ww_mutex, base);
+	if (ww_ctx) {
+		if (unlikely(ww_ctx == READ_ONCE(ww->ctx)))
+			return -EALREADY;
+
+		/*
+		 * Reset the wounded flag after a kill. No other process can
+		 * race and wound us here since they can't have a valid owner
+		 * pointer if we don't have any locks held.
+		 */
+		if (ww_ctx->acquired == 0)
+			ww_ctx->wounded = 0;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+		nest_lock = &ww_ctx->dep_map;
+#endif
+	}
+
+	preempt_disable();
+	mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
+
+	trace_contention_begin(lock, LCB_F_MUTEX | LCB_F_SPIN);
+	if (__mutex_trylock(lock) ||
+	    mutex_optimistic_spin(lock, ww_ctx, NULL)) {
+		/* got the lock, yay! */
+		lock_acquired(&lock->dep_map, ip);
+		if (ww_ctx)
+			ww_mutex_set_context_fastpath(ww, ww_ctx);
+		trace_contention_end(lock, 0);
+		preempt_enable();
+		return 0;
+	}
+
+	raw_spin_lock(&lock->wait_lock);
+	/*
+	 * After waiting to acquire the wait_lock, try again.
+	 */
+	if (__mutex_trylock(lock)) {
+		if (ww_ctx)
+			__ww_mutex_check_waiters(lock, ww_ctx);
+
+		goto skip_wait;
+	}
+
+	debug_mutex_lock_common(lock, &waiter);
+	waiter.task = current;
+	if (use_ww_ctx)
+		waiter.ww_ctx = ww_ctx;
+
+	lock_contended(&lock->dep_map, ip);
+
+	if (!use_ww_ctx) {
+		/* add waiting tasks to the end of the waitqueue (FIFO): */
+		__mutex_add_waiter(lock, &waiter, &lock->wait_list);
+	} else {
+		/*
+		 * Add in stamp order, waking up waiters that must kill
+		 * themselves.
+		 */
+		ret = __ww_mutex_add_waiter(&waiter, lock, ww_ctx);
+		if (ret)
+			goto err_early_kill;
+	}
+
+	set_current_state(state);
+	trace_contention_begin(lock, LCB_F_MUTEX);
+	for (;;) {
+		bool first;
+
+		/*
+		 * Once we hold wait_lock, we're serialized against
+		 * mutex_unlock() handing the lock off to us, do a trylock
+		 * before testing the error conditions to make sure we pick up
+		 * the handoff.
+		 */
+		if (__mutex_trylock(lock))
+			goto acquired;
+
+		/*
+		 * Check for signals and kill conditions while holding
+		 * wait_lock. This ensures the lock cancellation is ordered
+		 * against mutex_unlock() and wake-ups do not go missing.
+		 */
+		if (signal_pending_state(state, current)) {
+			ret = -EINTR;
+			goto err;
+		}
+
+		if (ww_ctx) {
+			ret = __ww_mutex_check_kill(lock, &waiter, ww_ctx);
+			if (ret)
+				goto err;
+		}
+
+		raw_spin_unlock(&lock->wait_lock);
+		schedule_preempt_disabled();
+
+		first = __mutex_waiter_is_first(lock, &waiter);
+
+		set_current_state(state);
+		/*
+		 * Here we order against unlock; we must either see it change
+		 * state back to RUNNING and fall through the next schedule(),
+		 * or we must see its unlock and acquire.
+		 */
+		if (__mutex_trylock_or_handoff(lock, first))
+			break;
+
+		if (first) {
+			trace_contention_begin(lock, LCB_F_MUTEX | LCB_F_SPIN);
+			if (mutex_optimistic_spin(lock, ww_ctx, &waiter))
+				break;
+			trace_contention_begin(lock, LCB_F_MUTEX);
+		}
+
+		raw_spin_lock(&lock->wait_lock);
+	}
+	raw_spin_lock(&lock->wait_lock);
+acquired:
+	__set_current_state(TASK_RUNNING);
+
+	if (ww_ctx) {
+		/*
+		 * Wound-Wait; we stole the lock (!first_waiter), check the
+		 * waiters as anyone might want to wound us.
+		 */
+		if (!ww_ctx->is_wait_die &&
+		    !__mutex_waiter_is_first(lock, &waiter))
+			__ww_mutex_check_waiters(lock, ww_ctx);
+	}
+
+	__mutex_remove_waiter(lock, &waiter);
+
+	debug_mutex_free_waiter(&waiter);
+
+skip_wait:
+	/* got the lock - cleanup and rejoice! */
+	lock_acquired(&lock->dep_map, ip);
+	trace_contention_end(lock, 0);
+
+	if (ww_ctx)
+		ww_mutex_lock_acquired(ww, ww_ctx);
+
+	raw_spin_unlock(&lock->wait_lock);
+	preempt_enable();
+	return 0;
+
+err:
+	__set_current_state(TASK_RUNNING);
+	__mutex_remove_waiter(lock, &waiter);
+err_early_kill:
+	trace_contention_end(lock, ret);
+	raw_spin_unlock(&lock->wait_lock);
+	debug_mutex_free_waiter(&waiter);
+	mutex_release(&lock->dep_map, ip);
+	preempt_enable();
+	return ret;
+}
+
+static int __sched
+__mutex_lock(struct mutex *lock, unsigned int state, unsigned int subclass,
+	     struct lockdep_map *nest_lock, unsigned long ip)
+{
+	return __mutex_lock_common(lock, state, subclass, nest_lock, ip, NULL, false);
+}
+
+static int __sched
+__ww_mutex_lock(struct mutex *lock, unsigned int state, unsigned int subclass,
+		unsigned long ip, struct ww_acquire_ctx *ww_ctx)
+{
+	return __mutex_lock_common(lock, state, subclass, NULL, ip, ww_ctx, true);
+}
+
+/**
+ * ww_mutex_trylock - tries to acquire the w/w mutex with optional acquire context
+ * @ww: mutex to lock
+ * @ww_ctx: optional w/w acquire context
+ *
+ * Trylocks a mutex with the optional acquire context; no deadlock detection is
+ * possible. Returns 1 if the mutex has been acquired successfully, 0 otherwise.
+ *
+ * Unlike ww_mutex_lock, no deadlock handling is performed. However, if a @ctx is
+ * specified, -EALREADY handling may happen in calls to ww_mutex_trylock.
+ *
+ * A mutex acquired with this function must be released with ww_mutex_unlock.
+ */
+int ww_mutex_trylock(struct ww_mutex *ww, struct ww_acquire_ctx *ww_ctx)
+{
+	if (!ww_ctx)
+		return mutex_trylock(&ww->base);
+
+	MUTEX_WARN_ON(ww->base.magic != &ww->base);
+
+	/*
+	 * Reset the wounded flag after a kill. No other process can
+	 * race and wound us here, since they can't have a valid owner
+	 * pointer if we don't have any locks held.
+	 */
+	if (ww_ctx->acquired == 0)
+		ww_ctx->wounded = 0;
+
+	if (__mutex_trylock(&ww->base)) {
+		ww_mutex_set_context_fastpath(ww, ww_ctx);
+		mutex_acquire_nest(&ww->base.dep_map, 0, 1, &ww_ctx->dep_map, _RET_IP_);
+		return 1;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(ww_mutex_trylock);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __sched
+mutex_lock_nested(struct mutex *lock, unsigned int subclass)
+{
+	__mutex_lock(lock, TASK_UNINTERRUPTIBLE, subclass, NULL, _RET_IP_);
+}
+
+EXPORT_SYMBOL_GPL(mutex_lock_nested);
+
+void __sched
+_mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
+{
+	__mutex_lock(lock, TASK_UNINTERRUPTIBLE, 0, nest, _RET_IP_);
+}
+EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
+
+int __sched
+mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass)
+{
+	return __mutex_lock(lock, TASK_KILLABLE, subclass, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_killable_nested);
+
+int __sched
+mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
+{
+	return __mutex_lock(lock, TASK_INTERRUPTIBLE, subclass, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
+
+void __sched
+mutex_lock_io_nested(struct mutex *lock, unsigned int subclass)
+{
+	int token;
+
+	might_sleep();
+
+	token = io_schedule_prepare();
+	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
+			    subclass, NULL, _RET_IP_, NULL, 0);
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_io_nested);
+
+static inline int
+ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
+	unsigned tmp;
+
+	if (ctx->deadlock_inject_countdown-- == 0) {
+		tmp = ctx->deadlock_inject_interval;
+		if (tmp > UINT_MAX/4)
+			tmp = UINT_MAX;
+		else
+			tmp = tmp*2 + tmp + tmp/2;
+
+		ctx->deadlock_inject_interval = tmp;
+		ctx->deadlock_inject_countdown = tmp;
+		ctx->contending_lock = lock;
+
+		ww_mutex_unlock(lock);
+
+		return -EDEADLK;
+	}
+#endif
+
+	return 0;
+}
+
+int __sched
+ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	int ret;
+
+	might_sleep();
+	ret =  __ww_mutex_lock(&lock->base, TASK_UNINTERRUPTIBLE,
+			       0, _RET_IP_, ctx);
+	if (!ret && ctx && ctx->acquired > 1)
+		return ww_mutex_deadlock_injection(lock, ctx);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ww_mutex_lock);
+
+int __sched
+ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	int ret;
+
+	might_sleep();
+	ret = __ww_mutex_lock(&lock->base, TASK_INTERRUPTIBLE,
+			      0, _RET_IP_, ctx);
+
+	if (!ret && ctx && ctx->acquired > 1)
+		return ww_mutex_deadlock_injection(lock, ctx);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ww_mutex_lock_interruptible);
+
+#endif
+
+/*
+ * Release the lock, slowpath:
+ */
+static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigned long ip)
+{
+	struct task_struct *next = NULL;
+	DEFINE_WAKE_Q(wake_q);
+	unsigned long owner;
+
+	mutex_release(&lock->dep_map, ip);
+
+	/*
+	 * Release the lock before (potentially) taking the spinlock such that
+	 * other contenders can get on with things ASAP.
+	 *
+	 * Except when HANDOFF, in that case we must not clear the owner field,
+	 * but instead set it to the top waiter.
+	 */
+	owner = atomic_long_read(&lock->owner);
+	for (;;) {
+		MUTEX_WARN_ON(__owner_task(owner) != current);
+		MUTEX_WARN_ON(owner & MUTEX_FLAG_PICKUP);
+
+		if (owner & MUTEX_FLAG_HANDOFF)
+			break;
+
+		if (atomic_long_try_cmpxchg_release(&lock->owner, &owner, __owner_flags(owner))) {
+			if (owner & MUTEX_FLAG_WAITERS)
+				break;
+
+			return;
+		}
+	}
+
+	raw_spin_lock(&lock->wait_lock);
+	debug_mutex_unlock(lock);
+	if (!list_empty(&lock->wait_list)) {
+		/* get the first entry from the wait-list: */
+		struct mutex_waiter *waiter =
+			list_first_entry(&lock->wait_list,
+					 struct mutex_waiter, list);
+
+		next = waiter->task;
+
+		debug_mutex_wake_waiter(lock, waiter);
+		wake_q_add(&wake_q, next);
+	}
+
+	if (owner & MUTEX_FLAG_HANDOFF)
+		__mutex_handoff(lock, next);
+
+	raw_spin_unlock(&lock->wait_lock);
+
+	wake_up_q(&wake_q);
+}
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+/*
+ * Here come the less common (and hence less performance-critical) APIs:
+ * mutex_lock_interruptible() and mutex_trylock().
+ */
+static noinline int __sched
+__mutex_lock_killable_slowpath(struct mutex *lock);
+
+static noinline int __sched
+__mutex_lock_interruptible_slowpath(struct mutex *lock);
+
+/**
+ * mutex_lock_interruptible() - Acquire the mutex, interruptible by signals.
+ * @lock: The mutex to be acquired.
+ *
+ * Lock the mutex like mutex_lock().  If a signal is delivered while the
+ * process is sleeping, this function will return without acquiring the
+ * mutex.
+ *
+ * Context: Process context.
+ * Return: 0 if the lock was successfully acquired or %-EINTR if a
+ * signal arrived.
+ */
+int __sched mutex_lock_interruptible(struct mutex *lock)
+{
+	might_sleep();
+
+	if (__mutex_trylock_fast(lock))
+		return 0;
+
+	return __mutex_lock_interruptible_slowpath(lock);
+}
+
+EXPORT_SYMBOL(mutex_lock_interruptible);
+
+/**
+ * mutex_lock_killable() - Acquire the mutex, interruptible by fatal signals.
+ * @lock: The mutex to be acquired.
+ *
+ * Lock the mutex like mutex_lock().  If a signal which will be fatal to
+ * the current process is delivered while the process is sleeping, this
+ * function will return without acquiring the mutex.
+ *
+ * Context: Process context.
+ * Return: 0 if the lock was successfully acquired or %-EINTR if a
+ * fatal signal arrived.
+ */
+int __sched mutex_lock_killable(struct mutex *lock)
+{
+	might_sleep();
+
+	if (__mutex_trylock_fast(lock))
+		return 0;
+
+	return __mutex_lock_killable_slowpath(lock);
+}
+EXPORT_SYMBOL(mutex_lock_killable);
+
+/**
+ * mutex_lock_io() - Acquire the mutex and mark the process as waiting for I/O
+ * @lock: The mutex to be acquired.
+ *
+ * Lock the mutex like mutex_lock().  While the task is waiting for this
+ * mutex, it will be accounted as being in the IO wait state by the
+ * scheduler.
+ *
+ * Context: Process context.
+ */
+void __sched mutex_lock_io(struct mutex *lock)
+{
+	int token;
+
+	token = io_schedule_prepare();
+	mutex_lock(lock);
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_io);
+
+static noinline void __sched
+__mutex_lock_slowpath(struct mutex *lock)
+{
+	__mutex_lock(lock, TASK_UNINTERRUPTIBLE, 0, NULL, _RET_IP_);
+}
+
+static noinline int __sched
+__mutex_lock_killable_slowpath(struct mutex *lock)
+{
+	return __mutex_lock(lock, TASK_KILLABLE, 0, NULL, _RET_IP_);
+}
+
+static noinline int __sched
+__mutex_lock_interruptible_slowpath(struct mutex *lock)
+{
+	return __mutex_lock(lock, TASK_INTERRUPTIBLE, 0, NULL, _RET_IP_);
+}
+
+static noinline int __sched
+__ww_mutex_lock_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	return __ww_mutex_lock(&lock->base, TASK_UNINTERRUPTIBLE, 0,
+			       _RET_IP_, ctx);
+}
+
+static noinline int __sched
+__ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock,
+					    struct ww_acquire_ctx *ctx)
+{
+	return __ww_mutex_lock(&lock->base, TASK_INTERRUPTIBLE, 0,
+			       _RET_IP_, ctx);
+}
+
+#endif
+
+/**
+ * mutex_trylock - try to acquire the mutex, without waiting
+ * @lock: the mutex to be acquired
+ *
+ * Try to acquire the mutex atomically. Returns 1 if the mutex
+ * has been acquired successfully, and 0 on contention.
+ *
+ * NOTE: this function follows the spin_trylock() convention, so
+ * it is negated from the down_trylock() return values! Be careful
+ * about this when converting semaphore users to mutexes.
+ *
+ * This function must not be used in interrupt context. The
+ * mutex must be released by the same task that acquired it.
+ */
+int __sched mutex_trylock(struct mutex *lock)
+{
+	bool locked;
+
+	MUTEX_WARN_ON(lock->magic != lock);
+
+	locked = __mutex_trylock(lock);
+	if (locked)
+		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+
+	return locked;
+}
+EXPORT_SYMBOL(mutex_trylock);
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+int __sched
+ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	might_sleep();
+
+	if (__mutex_trylock_fast(&lock->base)) {
+		if (ctx)
+			ww_mutex_set_context_fastpath(lock, ctx);
+		return 0;
+	}
+
+	return __ww_mutex_lock_slowpath(lock, ctx);
+}
+EXPORT_SYMBOL(ww_mutex_lock);
+
+int __sched
+ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	might_sleep();
+
+	if (__mutex_trylock_fast(&lock->base)) {
+		if (ctx)
+			ww_mutex_set_context_fastpath(lock, ctx);
+		return 0;
+	}
+
+	return __ww_mutex_lock_interruptible_slowpath(lock, ctx);
+}
+EXPORT_SYMBOL(ww_mutex_lock_interruptible);
+
+#endif /* !CONFIG_DEBUG_LOCK_ALLOC */
+#endif /* !CONFIG_PREEMPT_RT */
+
+/**
+ * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
+ * @cnt: the atomic which we are to dec
+ * @lock: the mutex to return holding if we dec to 0
+ *
+ * return true and hold lock if we dec to 0, return false otherwise
+ */
+int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
+{
+	/* dec if we can't possibly hit 0 */
+	if (atomic_add_unless(cnt, -1, 1))
+		return 0;
+	/* we might hit 0, so take the lock */
+	mutex_lock(lock);
+	if (!atomic_dec_and_test(cnt)) {
+		/* when we actually did the dec, we didn't hit 0 */
+		mutex_unlock(lock);
+		return 0;
+	}
+	/* we hit 0, and we hold the lock */
+	return 1;
+}
+EXPORT_SYMBOL(atomic_dec_and_mutex_lock);
diff --git a/kernel/locking/mutex.h b/kernel/locking/mutex.h
new file mode 100644
index 000000000..0b2a79c40
--- /dev/null
+++ b/kernel/locking/mutex.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Mutexes: blocking mutual exclusion locks
+ *
+ * started by Ingo Molnar:
+ *
+ *  Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ */
+
+/*
+ * This is the control structure for tasks blocked on mutex, which resides
+ * on the blocked task's kernel stack:
+ */
+struct mutex_waiter {
+	struct list_head	list;
+	struct task_struct	*task;
+	struct ww_acquire_ctx	*ww_ctx;
+#ifdef CONFIG_DEBUG_MUTEXES
+	void			*magic;
+#endif
+};
+
+#ifdef CONFIG_DEBUG_MUTEXES
+extern void debug_mutex_lock_common(struct mutex *lock,
+				    struct mutex_waiter *waiter);
+extern void debug_mutex_wake_waiter(struct mutex *lock,
+				    struct mutex_waiter *waiter);
+extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
+extern void debug_mutex_add_waiter(struct mutex *lock,
+				   struct mutex_waiter *waiter,
+				   struct task_struct *task);
+extern void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
+				      struct task_struct *task);
+extern void debug_mutex_unlock(struct mutex *lock);
+extern void debug_mutex_init(struct mutex *lock, const char *name,
+			     struct lock_class_key *key);
+#else /* CONFIG_DEBUG_MUTEXES */
+# define debug_mutex_lock_common(lock, waiter)		do { } while (0)
+# define debug_mutex_wake_waiter(lock, waiter)		do { } while (0)
+# define debug_mutex_free_waiter(waiter)		do { } while (0)
+# define debug_mutex_add_waiter(lock, waiter, ti)	do { } while (0)
+# define debug_mutex_remove_waiter(lock, waiter, ti)	do { } while (0)
+# define debug_mutex_unlock(lock)			do { } while (0)
+# define debug_mutex_init(lock, name, key)		do { } while (0)
+#endif /* !CONFIG_DEBUG_MUTEXES */
diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c
new file mode 100644
index 000000000..d5610ad52
--- /dev/null
+++ b/kernel/locking/osq_lock.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/percpu.h>
+#include <linux/sched.h>
+#include <linux/osq_lock.h>
+
+/*
+ * An MCS like lock especially tailored for optimistic spinning for sleeping
+ * lock implementations (mutex, rwsem, etc).
+ *
+ * Using a single mcs node per CPU is safe because sleeping locks should not be
+ * called from interrupt context and we have preemption disabled while
+ * spinning.
+ */
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct optimistic_spin_node, osq_node);
+
+/*
+ * We use the value 0 to represent "no CPU", thus the encoded value
+ * will be the CPU number incremented by 1.
+ */
+static inline int encode_cpu(int cpu_nr)
+{
+	return cpu_nr + 1;
+}
+
+static inline int node_cpu(struct optimistic_spin_node *node)
+{
+	return node->cpu - 1;
+}
+
+static inline struct optimistic_spin_node *decode_cpu(int encoded_cpu_val)
+{
+	int cpu_nr = encoded_cpu_val - 1;
+
+	return per_cpu_ptr(&osq_node, cpu_nr);
+}
+
+/*
+ * Get a stable @node->next pointer, either for unlock() or unqueue() purposes.
+ * Can return NULL in case we were the last queued and we updated @lock instead.
+ */
+static inline struct optimistic_spin_node *
+osq_wait_next(struct optimistic_spin_queue *lock,
+	      struct optimistic_spin_node *node,
+	      struct optimistic_spin_node *prev)
+{
+	struct optimistic_spin_node *next = NULL;
+	int curr = encode_cpu(smp_processor_id());
+	int old;
+
+	/*
+	 * If there is a prev node in queue, then the 'old' value will be
+	 * the prev node's CPU #, else it's set to OSQ_UNLOCKED_VAL since if
+	 * we're currently last in queue, then the queue will then become empty.
+	 */
+	old = prev ? prev->cpu : OSQ_UNLOCKED_VAL;
+
+	for (;;) {
+		if (atomic_read(&lock->tail) == curr &&
+		    atomic_cmpxchg_acquire(&lock->tail, curr, old) == curr) {
+			/*
+			 * We were the last queued, we moved @lock back. @prev
+			 * will now observe @lock and will complete its
+			 * unlock()/unqueue().
+			 */
+			break;
+		}
+
+		/*
+		 * We must xchg() the @node->next value, because if we were to
+		 * leave it in, a concurrent unlock()/unqueue() from
+		 * @node->next might complete Step-A and think its @prev is
+		 * still valid.
+		 *
+		 * If the concurrent unlock()/unqueue() wins the race, we'll
+		 * wait for either @lock to point to us, through its Step-B, or
+		 * wait for a new @node->next from its Step-C.
+		 */
+		if (node->next) {
+			next = xchg(&node->next, NULL);
+			if (next)
+				break;
+		}
+
+		cpu_relax();
+	}
+
+	return next;
+}
+
+bool osq_lock(struct optimistic_spin_queue *lock)
+{
+	struct optimistic_spin_node *node = this_cpu_ptr(&osq_node);
+	struct optimistic_spin_node *prev, *next;
+	int curr = encode_cpu(smp_processor_id());
+	int old;
+
+	node->locked = 0;
+	node->next = NULL;
+	node->cpu = curr;
+
+	/*
+	 * We need both ACQUIRE (pairs with corresponding RELEASE in
+	 * unlock() uncontended, or fastpath) and RELEASE (to publish
+	 * the node fields we just initialised) semantics when updating
+	 * the lock tail.
+	 */
+	old = atomic_xchg(&lock->tail, curr);
+	if (old == OSQ_UNLOCKED_VAL)
+		return true;
+
+	prev = decode_cpu(old);
+	node->prev = prev;
+
+	/*
+	 * osq_lock()			unqueue
+	 *
+	 * node->prev = prev		osq_wait_next()
+	 * WMB				MB
+	 * prev->next = node		next->prev = prev // unqueue-C
+	 *
+	 * Here 'node->prev' and 'next->prev' are the same variable and we need
+	 * to ensure these stores happen in-order to avoid corrupting the list.
+	 */
+	smp_wmb();
+
+	WRITE_ONCE(prev->next, node);
+
+	/*
+	 * Normally @prev is untouchable after the above store; because at that
+	 * moment unlock can proceed and wipe the node element from stack.
+	 *
+	 * However, since our nodes are static per-cpu storage, we're
+	 * guaranteed their existence -- this allows us to apply
+	 * cmpxchg in an attempt to undo our queueing.
+	 */
+
+	/*
+	 * Wait to acquire the lock or cancellation. Note that need_resched()
+	 * will come with an IPI, which will wake smp_cond_load_relaxed() if it
+	 * is implemented with a monitor-wait. vcpu_is_preempted() relies on
+	 * polling, be careful.
+	 */
+	if (smp_cond_load_relaxed(&node->locked, VAL || need_resched() ||
+				  vcpu_is_preempted(node_cpu(node->prev))))
+		return true;
+
+	/* unqueue */
+	/*
+	 * Step - A  -- stabilize @prev
+	 *
+	 * Undo our @prev->next assignment; this will make @prev's
+	 * unlock()/unqueue() wait for a next pointer since @lock points to us
+	 * (or later).
+	 */
+
+	for (;;) {
+		/*
+		 * cpu_relax() below implies a compiler barrier which would
+		 * prevent this comparison being optimized away.
+		 */
+		if (data_race(prev->next) == node &&
+		    cmpxchg(&prev->next, node, NULL) == node)
+			break;
+
+		/*
+		 * We can only fail the cmpxchg() racing against an unlock(),
+		 * in which case we should observe @node->locked becoming
+		 * true.
+		 */
+		if (smp_load_acquire(&node->locked))
+			return true;
+
+		cpu_relax();
+
+		/*
+		 * Or we race against a concurrent unqueue()'s step-B, in which
+		 * case its step-C will write us a new @node->prev pointer.
+		 */
+		prev = READ_ONCE(node->prev);
+	}
+
+	/*
+	 * Step - B -- stabilize @next
+	 *
+	 * Similar to unlock(), wait for @node->next or move @lock from @node
+	 * back to @prev.
+	 */
+
+	next = osq_wait_next(lock, node, prev);
+	if (!next)
+		return false;
+
+	/*
+	 * Step - C -- unlink
+	 *
+	 * @prev is stable because its still waiting for a new @prev->next
+	 * pointer, @next is stable because our @node->next pointer is NULL and
+	 * it will wait in Step-A.
+	 */
+
+	WRITE_ONCE(next->prev, prev);
+	WRITE_ONCE(prev->next, next);
+
+	return false;
+}
+
+void osq_unlock(struct optimistic_spin_queue *lock)
+{
+	struct optimistic_spin_node *node, *next;
+	int curr = encode_cpu(smp_processor_id());
+
+	/*
+	 * Fast path for the uncontended case.
+	 */
+	if (likely(atomic_cmpxchg_release(&lock->tail, curr,
+					  OSQ_UNLOCKED_VAL) == curr))
+		return;
+
+	/*
+	 * Second most likely case.
+	 */
+	node = this_cpu_ptr(&osq_node);
+	next = xchg(&node->next, NULL);
+	if (next) {
+		WRITE_ONCE(next->locked, 1);
+		return;
+	}
+
+	next = osq_wait_next(lock, node, NULL);
+	if (next)
+		WRITE_ONCE(next->locked, 1);
+}
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
new file mode 100644
index 000000000..185bd1c90
--- /dev/null
+++ b/kernel/locking/percpu-rwsem.c
@@ -0,0 +1,282 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/atomic.h>
+#include <linux/percpu.h>
+#include <linux/wait.h>
+#include <linux/lockdep.h>
+#include <linux/percpu-rwsem.h>
+#include <linux/rcupdate.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/sched/debug.h>
+#include <linux/errno.h>
+#include <trace/events/lock.h>
+
+int __percpu_init_rwsem(struct percpu_rw_semaphore *sem,
+			const char *name, struct lock_class_key *key)
+{
+	sem->read_count = alloc_percpu(int);
+	if (unlikely(!sem->read_count))
+		return -ENOMEM;
+
+	rcu_sync_init(&sem->rss);
+	rcuwait_init(&sem->writer);
+	init_waitqueue_head(&sem->waiters);
+	atomic_set(&sem->block, 0);
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	debug_check_no_locks_freed((void *)sem, sizeof(*sem));
+	lockdep_init_map(&sem->dep_map, name, key, 0);
+#endif
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__percpu_init_rwsem);
+
+void percpu_free_rwsem(struct percpu_rw_semaphore *sem)
+{
+	/*
+	 * XXX: temporary kludge. The error path in alloc_super()
+	 * assumes that percpu_free_rwsem() is safe after kzalloc().
+	 */
+	if (!sem->read_count)
+		return;
+
+	rcu_sync_dtor(&sem->rss);
+	free_percpu(sem->read_count);
+	sem->read_count = NULL; /* catch use after free bugs */
+}
+EXPORT_SYMBOL_GPL(percpu_free_rwsem);
+
+static bool __percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
+{
+	this_cpu_inc(*sem->read_count);
+
+	/*
+	 * Due to having preemption disabled the decrement happens on
+	 * the same CPU as the increment, avoiding the
+	 * increment-on-one-CPU-and-decrement-on-another problem.
+	 *
+	 * If the reader misses the writer's assignment of sem->block, then the
+	 * writer is guaranteed to see the reader's increment.
+	 *
+	 * Conversely, any readers that increment their sem->read_count after
+	 * the writer looks are guaranteed to see the sem->block value, which
+	 * in turn means that they are guaranteed to immediately decrement
+	 * their sem->read_count, so that it doesn't matter that the writer
+	 * missed them.
+	 */
+
+	smp_mb(); /* A matches D */
+
+	/*
+	 * If !sem->block the critical section starts here, matched by the
+	 * release in percpu_up_write().
+	 */
+	if (likely(!atomic_read_acquire(&sem->block)))
+		return true;
+
+	this_cpu_dec(*sem->read_count);
+
+	/* Prod writer to re-evaluate readers_active_check() */
+	rcuwait_wake_up(&sem->writer);
+
+	return false;
+}
+
+static inline bool __percpu_down_write_trylock(struct percpu_rw_semaphore *sem)
+{
+	if (atomic_read(&sem->block))
+		return false;
+
+	return atomic_xchg(&sem->block, 1) == 0;
+}
+
+static bool __percpu_rwsem_trylock(struct percpu_rw_semaphore *sem, bool reader)
+{
+	if (reader) {
+		bool ret;
+
+		preempt_disable();
+		ret = __percpu_down_read_trylock(sem);
+		preempt_enable();
+
+		return ret;
+	}
+	return __percpu_down_write_trylock(sem);
+}
+
+/*
+ * The return value of wait_queue_entry::func means:
+ *
+ *  <0 - error, wakeup is terminated and the error is returned
+ *   0 - no wakeup, a next waiter is tried
+ *  >0 - woken, if EXCLUSIVE, counted towards @nr_exclusive.
+ *
+ * We use EXCLUSIVE for both readers and writers to preserve FIFO order,
+ * and play games with the return value to allow waking multiple readers.
+ *
+ * Specifically, we wake readers until we've woken a single writer, or until a
+ * trylock fails.
+ */
+static int percpu_rwsem_wake_function(struct wait_queue_entry *wq_entry,
+				      unsigned int mode, int wake_flags,
+				      void *key)
+{
+	bool reader = wq_entry->flags & WQ_FLAG_CUSTOM;
+	struct percpu_rw_semaphore *sem = key;
+	struct task_struct *p;
+
+	/* concurrent against percpu_down_write(), can get stolen */
+	if (!__percpu_rwsem_trylock(sem, reader))
+		return 1;
+
+	p = get_task_struct(wq_entry->private);
+	list_del_init(&wq_entry->entry);
+	smp_store_release(&wq_entry->private, NULL);
+
+	wake_up_process(p);
+	put_task_struct(p);
+
+	return !reader; /* wake (readers until) 1 writer */
+}
+
+static void percpu_rwsem_wait(struct percpu_rw_semaphore *sem, bool reader)
+{
+	DEFINE_WAIT_FUNC(wq_entry, percpu_rwsem_wake_function);
+	bool wait;
+
+	spin_lock_irq(&sem->waiters.lock);
+	/*
+	 * Serialize against the wakeup in percpu_up_write(), if we fail
+	 * the trylock, the wakeup must see us on the list.
+	 */
+	wait = !__percpu_rwsem_trylock(sem, reader);
+	if (wait) {
+		wq_entry.flags |= WQ_FLAG_EXCLUSIVE | reader * WQ_FLAG_CUSTOM;
+		__add_wait_queue_entry_tail(&sem->waiters, &wq_entry);
+	}
+	spin_unlock_irq(&sem->waiters.lock);
+
+	while (wait) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		if (!smp_load_acquire(&wq_entry.private))
+			break;
+		schedule();
+	}
+	__set_current_state(TASK_RUNNING);
+}
+
+bool __sched __percpu_down_read(struct percpu_rw_semaphore *sem, bool try)
+{
+	if (__percpu_down_read_trylock(sem))
+		return true;
+
+	if (try)
+		return false;
+
+	trace_contention_begin(sem, LCB_F_PERCPU | LCB_F_READ);
+	preempt_enable();
+	percpu_rwsem_wait(sem, /* .reader = */ true);
+	preempt_disable();
+	trace_contention_end(sem, 0);
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(__percpu_down_read);
+
+#define per_cpu_sum(var)						\
+({									\
+	typeof(var) __sum = 0;						\
+	int cpu;							\
+	compiletime_assert_atomic_type(__sum);				\
+	for_each_possible_cpu(cpu)					\
+		__sum += per_cpu(var, cpu);				\
+	__sum;								\
+})
+
+bool percpu_is_read_locked(struct percpu_rw_semaphore *sem)
+{
+	return per_cpu_sum(*sem->read_count) != 0 && !atomic_read(&sem->block);
+}
+EXPORT_SYMBOL_GPL(percpu_is_read_locked);
+
+/*
+ * Return true if the modular sum of the sem->read_count per-CPU variable is
+ * zero.  If this sum is zero, then it is stable due to the fact that if any
+ * newly arriving readers increment a given counter, they will immediately
+ * decrement that same counter.
+ *
+ * Assumes sem->block is set.
+ */
+static bool readers_active_check(struct percpu_rw_semaphore *sem)
+{
+	if (per_cpu_sum(*sem->read_count) != 0)
+		return false;
+
+	/*
+	 * If we observed the decrement; ensure we see the entire critical
+	 * section.
+	 */
+
+	smp_mb(); /* C matches B */
+
+	return true;
+}
+
+void __sched percpu_down_write(struct percpu_rw_semaphore *sem)
+{
+	might_sleep();
+	rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
+	trace_contention_begin(sem, LCB_F_PERCPU | LCB_F_WRITE);
+
+	/* Notify readers to take the slow path. */
+	rcu_sync_enter(&sem->rss);
+
+	/*
+	 * Try set sem->block; this provides writer-writer exclusion.
+	 * Having sem->block set makes new readers block.
+	 */
+	if (!__percpu_down_write_trylock(sem))
+		percpu_rwsem_wait(sem, /* .reader = */ false);
+
+	/* smp_mb() implied by __percpu_down_write_trylock() on success -- D matches A */
+
+	/*
+	 * If they don't see our store of sem->block, then we are guaranteed to
+	 * see their sem->read_count increment, and therefore will wait for
+	 * them.
+	 */
+
+	/* Wait for all active readers to complete. */
+	rcuwait_wait_event(&sem->writer, readers_active_check(sem), TASK_UNINTERRUPTIBLE);
+	trace_contention_end(sem, 0);
+}
+EXPORT_SYMBOL_GPL(percpu_down_write);
+
+void percpu_up_write(struct percpu_rw_semaphore *sem)
+{
+	rwsem_release(&sem->dep_map, _RET_IP_);
+
+	/*
+	 * Signal the writer is done, no fast path yet.
+	 *
+	 * One reason that we cannot just immediately flip to readers_fast is
+	 * that new readers might fail to see the results of this writer's
+	 * critical section.
+	 *
+	 * Therefore we force it through the slow path which guarantees an
+	 * acquire and thereby guarantees the critical section's consistency.
+	 */
+	atomic_set_release(&sem->block, 0);
+
+	/*
+	 * Prod any pending reader/writer to make progress.
+	 */
+	__wake_up(&sem->waiters, TASK_NORMAL, 1, sem);
+
+	/*
+	 * Once this completes (at least one RCU-sched grace period hence) the
+	 * reader fast path will be available again. Safe to use outside the
+	 * exclusive write lock because its counting.
+	 */
+	rcu_sync_exit(&sem->rss);
+}
+EXPORT_SYMBOL_GPL(percpu_up_write);
diff --git a/kernel/locking/qrwlock.c b/kernel/locking/qrwlock.c
new file mode 100644
index 000000000..d2ef312a8
--- /dev/null
+++ b/kernel/locking/qrwlock.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Queued read/write locks
+ *
+ * (C) Copyright 2013-2014 Hewlett-Packard Development Company, L.P.
+ *
+ * Authors: Waiman Long <waiman.long@hp.com>
+ */
+#include <linux/smp.h>
+#include <linux/bug.h>
+#include <linux/cpumask.h>
+#include <linux/percpu.h>
+#include <linux/hardirq.h>
+#include <linux/spinlock.h>
+#include <trace/events/lock.h>
+
+/**
+ * queued_read_lock_slowpath - acquire read lock of a queued rwlock
+ * @lock: Pointer to queued rwlock structure
+ */
+void __lockfunc queued_read_lock_slowpath(struct qrwlock *lock)
+{
+	/*
+	 * Readers come here when they cannot get the lock without waiting
+	 */
+	if (unlikely(in_interrupt())) {
+		/*
+		 * Readers in interrupt context will get the lock immediately
+		 * if the writer is just waiting (not holding the lock yet),
+		 * so spin with ACQUIRE semantics until the lock is available
+		 * without waiting in the queue.
+		 */
+		atomic_cond_read_acquire(&lock->cnts, !(VAL & _QW_LOCKED));
+		return;
+	}
+	atomic_sub(_QR_BIAS, &lock->cnts);
+
+	trace_contention_begin(lock, LCB_F_SPIN | LCB_F_READ);
+
+	/*
+	 * Put the reader into the wait queue
+	 */
+	arch_spin_lock(&lock->wait_lock);
+	atomic_add(_QR_BIAS, &lock->cnts);
+
+	/*
+	 * The ACQUIRE semantics of the following spinning code ensure
+	 * that accesses can't leak upwards out of our subsequent critical
+	 * section in the case that the lock is currently held for write.
+	 */
+	atomic_cond_read_acquire(&lock->cnts, !(VAL & _QW_LOCKED));
+
+	/*
+	 * Signal the next one in queue to become queue head
+	 */
+	arch_spin_unlock(&lock->wait_lock);
+
+	trace_contention_end(lock, 0);
+}
+EXPORT_SYMBOL(queued_read_lock_slowpath);
+
+/**
+ * queued_write_lock_slowpath - acquire write lock of a queued rwlock
+ * @lock : Pointer to queued rwlock structure
+ */
+void __lockfunc queued_write_lock_slowpath(struct qrwlock *lock)
+{
+	int cnts;
+
+	trace_contention_begin(lock, LCB_F_SPIN | LCB_F_WRITE);
+
+	/* Put the writer into the wait queue */
+	arch_spin_lock(&lock->wait_lock);
+
+	/* Try to acquire the lock directly if no reader is present */
+	if (!(cnts = atomic_read(&lock->cnts)) &&
+	    atomic_try_cmpxchg_acquire(&lock->cnts, &cnts, _QW_LOCKED))
+		goto unlock;
+
+	/* Set the waiting flag to notify readers that a writer is pending */
+	atomic_or(_QW_WAITING, &lock->cnts);
+
+	/* When no more readers or writers, set the locked flag */
+	do {
+		cnts = atomic_cond_read_relaxed(&lock->cnts, VAL == _QW_WAITING);
+	} while (!atomic_try_cmpxchg_acquire(&lock->cnts, &cnts, _QW_LOCKED));
+unlock:
+	arch_spin_unlock(&lock->wait_lock);
+
+	trace_contention_end(lock, 0);
+}
+EXPORT_SYMBOL(queued_write_lock_slowpath);
diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c
new file mode 100644
index 000000000..2b2337877
--- /dev/null
+++ b/kernel/locking/qspinlock.c
@@ -0,0 +1,596 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Queued spinlock
+ *
+ * (C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P.
+ * (C) Copyright 2013-2014,2018 Red Hat, Inc.
+ * (C) Copyright 2015 Intel Corp.
+ * (C) Copyright 2015 Hewlett-Packard Enterprise Development LP
+ *
+ * Authors: Waiman Long <longman@redhat.com>
+ *          Peter Zijlstra <peterz@infradead.org>
+ */
+
+#ifndef _GEN_PV_LOCK_SLOWPATH
+
+#include <linux/smp.h>
+#include <linux/bug.h>
+#include <linux/cpumask.h>
+#include <linux/percpu.h>
+#include <linux/hardirq.h>
+#include <linux/mutex.h>
+#include <linux/prefetch.h>
+#include <asm/byteorder.h>
+#include <asm/qspinlock.h>
+#include <trace/events/lock.h>
+
+/*
+ * Include queued spinlock statistics code
+ */
+#include "qspinlock_stat.h"
+
+/*
+ * The basic principle of a queue-based spinlock can best be understood
+ * by studying a classic queue-based spinlock implementation called the
+ * MCS lock. A copy of the original MCS lock paper ("Algorithms for Scalable
+ * Synchronization on Shared-Memory Multiprocessors by Mellor-Crummey and
+ * Scott") is available at
+ *
+ * https://bugzilla.kernel.org/show_bug.cgi?id=206115
+ *
+ * This queued spinlock implementation is based on the MCS lock, however to
+ * make it fit the 4 bytes we assume spinlock_t to be, and preserve its
+ * existing API, we must modify it somehow.
+ *
+ * In particular; where the traditional MCS lock consists of a tail pointer
+ * (8 bytes) and needs the next pointer (another 8 bytes) of its own node to
+ * unlock the next pending (next->locked), we compress both these: {tail,
+ * next->locked} into a single u32 value.
+ *
+ * Since a spinlock disables recursion of its own context and there is a limit
+ * to the contexts that can nest; namely: task, softirq, hardirq, nmi. As there
+ * are at most 4 nesting levels, it can be encoded by a 2-bit number. Now
+ * we can encode the tail by combining the 2-bit nesting level with the cpu
+ * number. With one byte for the lock value and 3 bytes for the tail, only a
+ * 32-bit word is now needed. Even though we only need 1 bit for the lock,
+ * we extend it to a full byte to achieve better performance for architectures
+ * that support atomic byte write.
+ *
+ * We also change the first spinner to spin on the lock bit instead of its
+ * node; whereby avoiding the need to carry a node from lock to unlock, and
+ * preserving existing lock API. This also makes the unlock code simpler and
+ * faster.
+ *
+ * N.B. The current implementation only supports architectures that allow
+ *      atomic operations on smaller 8-bit and 16-bit data types.
+ *
+ */
+
+#include "mcs_spinlock.h"
+#define MAX_NODES	4
+
+/*
+ * On 64-bit architectures, the mcs_spinlock structure will be 16 bytes in
+ * size and four of them will fit nicely in one 64-byte cacheline. For
+ * pvqspinlock, however, we need more space for extra data. To accommodate
+ * that, we insert two more long words to pad it up to 32 bytes. IOW, only
+ * two of them can fit in a cacheline in this case. That is OK as it is rare
+ * to have more than 2 levels of slowpath nesting in actual use. We don't
+ * want to penalize pvqspinlocks to optimize for a rare case in native
+ * qspinlocks.
+ */
+struct qnode {
+	struct mcs_spinlock mcs;
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+	long reserved[2];
+#endif
+};
+
+/*
+ * The pending bit spinning loop count.
+ * This heuristic is used to limit the number of lockword accesses
+ * made by atomic_cond_read_relaxed when waiting for the lock to
+ * transition out of the "== _Q_PENDING_VAL" state. We don't spin
+ * indefinitely because there's no guarantee that we'll make forward
+ * progress.
+ */
+#ifndef _Q_PENDING_LOOPS
+#define _Q_PENDING_LOOPS	1
+#endif
+
+/*
+ * Per-CPU queue node structures; we can never have more than 4 nested
+ * contexts: task, softirq, hardirq, nmi.
+ *
+ * Exactly fits one 64-byte cacheline on a 64-bit architecture.
+ *
+ * PV doubles the storage and uses the second cacheline for PV state.
+ */
+static DEFINE_PER_CPU_ALIGNED(struct qnode, qnodes[MAX_NODES]);
+
+/*
+ * We must be able to distinguish between no-tail and the tail at 0:0,
+ * therefore increment the cpu number by one.
+ */
+
+static inline __pure u32 encode_tail(int cpu, int idx)
+{
+	u32 tail;
+
+	tail  = (cpu + 1) << _Q_TAIL_CPU_OFFSET;
+	tail |= idx << _Q_TAIL_IDX_OFFSET; /* assume < 4 */
+
+	return tail;
+}
+
+static inline __pure struct mcs_spinlock *decode_tail(u32 tail)
+{
+	int cpu = (tail >> _Q_TAIL_CPU_OFFSET) - 1;
+	int idx = (tail &  _Q_TAIL_IDX_MASK) >> _Q_TAIL_IDX_OFFSET;
+
+	return per_cpu_ptr(&qnodes[idx].mcs, cpu);
+}
+
+static inline __pure
+struct mcs_spinlock *grab_mcs_node(struct mcs_spinlock *base, int idx)
+{
+	return &((struct qnode *)base + idx)->mcs;
+}
+
+#define _Q_LOCKED_PENDING_MASK (_Q_LOCKED_MASK | _Q_PENDING_MASK)
+
+#if _Q_PENDING_BITS == 8
+/**
+ * clear_pending - clear the pending bit.
+ * @lock: Pointer to queued spinlock structure
+ *
+ * *,1,* -> *,0,*
+ */
+static __always_inline void clear_pending(struct qspinlock *lock)
+{
+	WRITE_ONCE(lock->pending, 0);
+}
+
+/**
+ * clear_pending_set_locked - take ownership and clear the pending bit.
+ * @lock: Pointer to queued spinlock structure
+ *
+ * *,1,0 -> *,0,1
+ *
+ * Lock stealing is not allowed if this function is used.
+ */
+static __always_inline void clear_pending_set_locked(struct qspinlock *lock)
+{
+	WRITE_ONCE(lock->locked_pending, _Q_LOCKED_VAL);
+}
+
+/*
+ * xchg_tail - Put in the new queue tail code word & retrieve previous one
+ * @lock : Pointer to queued spinlock structure
+ * @tail : The new queue tail code word
+ * Return: The previous queue tail code word
+ *
+ * xchg(lock, tail), which heads an address dependency
+ *
+ * p,*,* -> n,*,* ; prev = xchg(lock, node)
+ */
+static __always_inline u32 xchg_tail(struct qspinlock *lock, u32 tail)
+{
+	/*
+	 * We can use relaxed semantics since the caller ensures that the
+	 * MCS node is properly initialized before updating the tail.
+	 */
+	return (u32)xchg_relaxed(&lock->tail,
+				 tail >> _Q_TAIL_OFFSET) << _Q_TAIL_OFFSET;
+}
+
+#else /* _Q_PENDING_BITS == 8 */
+
+/**
+ * clear_pending - clear the pending bit.
+ * @lock: Pointer to queued spinlock structure
+ *
+ * *,1,* -> *,0,*
+ */
+static __always_inline void clear_pending(struct qspinlock *lock)
+{
+	atomic_andnot(_Q_PENDING_VAL, &lock->val);
+}
+
+/**
+ * clear_pending_set_locked - take ownership and clear the pending bit.
+ * @lock: Pointer to queued spinlock structure
+ *
+ * *,1,0 -> *,0,1
+ */
+static __always_inline void clear_pending_set_locked(struct qspinlock *lock)
+{
+	atomic_add(-_Q_PENDING_VAL + _Q_LOCKED_VAL, &lock->val);
+}
+
+/**
+ * xchg_tail - Put in the new queue tail code word & retrieve previous one
+ * @lock : Pointer to queued spinlock structure
+ * @tail : The new queue tail code word
+ * Return: The previous queue tail code word
+ *
+ * xchg(lock, tail)
+ *
+ * p,*,* -> n,*,* ; prev = xchg(lock, node)
+ */
+static __always_inline u32 xchg_tail(struct qspinlock *lock, u32 tail)
+{
+	u32 old, new, val = atomic_read(&lock->val);
+
+	for (;;) {
+		new = (val & _Q_LOCKED_PENDING_MASK) | tail;
+		/*
+		 * We can use relaxed semantics since the caller ensures that
+		 * the MCS node is properly initialized before updating the
+		 * tail.
+		 */
+		old = atomic_cmpxchg_relaxed(&lock->val, val, new);
+		if (old == val)
+			break;
+
+		val = old;
+	}
+	return old;
+}
+#endif /* _Q_PENDING_BITS == 8 */
+
+/**
+ * queued_fetch_set_pending_acquire - fetch the whole lock value and set pending
+ * @lock : Pointer to queued spinlock structure
+ * Return: The previous lock value
+ *
+ * *,*,* -> *,1,*
+ */
+#ifndef queued_fetch_set_pending_acquire
+static __always_inline u32 queued_fetch_set_pending_acquire(struct qspinlock *lock)
+{
+	return atomic_fetch_or_acquire(_Q_PENDING_VAL, &lock->val);
+}
+#endif
+
+/**
+ * set_locked - Set the lock bit and own the lock
+ * @lock: Pointer to queued spinlock structure
+ *
+ * *,*,0 -> *,0,1
+ */
+static __always_inline void set_locked(struct qspinlock *lock)
+{
+	WRITE_ONCE(lock->locked, _Q_LOCKED_VAL);
+}
+
+
+/*
+ * Generate the native code for queued_spin_unlock_slowpath(); provide NOPs for
+ * all the PV callbacks.
+ */
+
+static __always_inline void __pv_init_node(struct mcs_spinlock *node) { }
+static __always_inline void __pv_wait_node(struct mcs_spinlock *node,
+					   struct mcs_spinlock *prev) { }
+static __always_inline void __pv_kick_node(struct qspinlock *lock,
+					   struct mcs_spinlock *node) { }
+static __always_inline u32  __pv_wait_head_or_lock(struct qspinlock *lock,
+						   struct mcs_spinlock *node)
+						   { return 0; }
+
+#define pv_enabled()		false
+
+#define pv_init_node		__pv_init_node
+#define pv_wait_node		__pv_wait_node
+#define pv_kick_node		__pv_kick_node
+#define pv_wait_head_or_lock	__pv_wait_head_or_lock
+
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+#define queued_spin_lock_slowpath	native_queued_spin_lock_slowpath
+#endif
+
+#endif /* _GEN_PV_LOCK_SLOWPATH */
+
+/**
+ * queued_spin_lock_slowpath - acquire the queued spinlock
+ * @lock: Pointer to queued spinlock structure
+ * @val: Current value of the queued spinlock 32-bit word
+ *
+ * (queue tail, pending bit, lock value)
+ *
+ *              fast     :    slow                                  :    unlock
+ *                       :                                          :
+ * uncontended  (0,0,0) -:--> (0,0,1) ------------------------------:--> (*,*,0)
+ *                       :       | ^--------.------.             /  :
+ *                       :       v           \      \            |  :
+ * pending               :    (0,1,1) +--> (0,1,0)   \           |  :
+ *                       :       | ^--'              |           |  :
+ *                       :       v                   |           |  :
+ * uncontended           :    (n,x,y) +--> (n,0,0) --'           |  :
+ *   queue               :       | ^--'                          |  :
+ *                       :       v                               |  :
+ * contended             :    (*,x,y) +--> (*,0,0) ---> (*,0,1) -'  :
+ *   queue               :         ^--'                             :
+ */
+void __lockfunc queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
+{
+	struct mcs_spinlock *prev, *next, *node;
+	u32 old, tail;
+	int idx;
+
+	BUILD_BUG_ON(CONFIG_NR_CPUS >= (1U << _Q_TAIL_CPU_BITS));
+
+	if (pv_enabled())
+		goto pv_queue;
+
+	if (virt_spin_lock(lock))
+		return;
+
+	/*
+	 * Wait for in-progress pending->locked hand-overs with a bounded
+	 * number of spins so that we guarantee forward progress.
+	 *
+	 * 0,1,0 -> 0,0,1
+	 */
+	if (val == _Q_PENDING_VAL) {
+		int cnt = _Q_PENDING_LOOPS;
+		val = atomic_cond_read_relaxed(&lock->val,
+					       (VAL != _Q_PENDING_VAL) || !cnt--);
+	}
+
+	/*
+	 * If we observe any contention; queue.
+	 */
+	if (val & ~_Q_LOCKED_MASK)
+		goto queue;
+
+	/*
+	 * trylock || pending
+	 *
+	 * 0,0,* -> 0,1,* -> 0,0,1 pending, trylock
+	 */
+	val = queued_fetch_set_pending_acquire(lock);
+
+	/*
+	 * If we observe contention, there is a concurrent locker.
+	 *
+	 * Undo and queue; our setting of PENDING might have made the
+	 * n,0,0 -> 0,0,0 transition fail and it will now be waiting
+	 * on @next to become !NULL.
+	 */
+	if (unlikely(val & ~_Q_LOCKED_MASK)) {
+
+		/* Undo PENDING if we set it. */
+		if (!(val & _Q_PENDING_MASK))
+			clear_pending(lock);
+
+		goto queue;
+	}
+
+	/*
+	 * We're pending, wait for the owner to go away.
+	 *
+	 * 0,1,1 -> 0,1,0
+	 *
+	 * this wait loop must be a load-acquire such that we match the
+	 * store-release that clears the locked bit and create lock
+	 * sequentiality; this is because not all
+	 * clear_pending_set_locked() implementations imply full
+	 * barriers.
+	 */
+	if (val & _Q_LOCKED_MASK)
+		atomic_cond_read_acquire(&lock->val, !(VAL & _Q_LOCKED_MASK));
+
+	/*
+	 * take ownership and clear the pending bit.
+	 *
+	 * 0,1,0 -> 0,0,1
+	 */
+	clear_pending_set_locked(lock);
+	lockevent_inc(lock_pending);
+	return;
+
+	/*
+	 * End of pending bit optimistic spinning and beginning of MCS
+	 * queuing.
+	 */
+queue:
+	lockevent_inc(lock_slowpath);
+pv_queue:
+	node = this_cpu_ptr(&qnodes[0].mcs);
+	idx = node->count++;
+	tail = encode_tail(smp_processor_id(), idx);
+
+	trace_contention_begin(lock, LCB_F_SPIN);
+
+	/*
+	 * 4 nodes are allocated based on the assumption that there will
+	 * not be nested NMIs taking spinlocks. That may not be true in
+	 * some architectures even though the chance of needing more than
+	 * 4 nodes will still be extremely unlikely. When that happens,
+	 * we fall back to spinning on the lock directly without using
+	 * any MCS node. This is not the most elegant solution, but is
+	 * simple enough.
+	 */
+	if (unlikely(idx >= MAX_NODES)) {
+		lockevent_inc(lock_no_node);
+		while (!queued_spin_trylock(lock))
+			cpu_relax();
+		goto release;
+	}
+
+	node = grab_mcs_node(node, idx);
+
+	/*
+	 * Keep counts of non-zero index values:
+	 */
+	lockevent_cond_inc(lock_use_node2 + idx - 1, idx);
+
+	/*
+	 * Ensure that we increment the head node->count before initialising
+	 * the actual node. If the compiler is kind enough to reorder these
+	 * stores, then an IRQ could overwrite our assignments.
+	 */
+	barrier();
+
+	node->locked = 0;
+	node->next = NULL;
+	pv_init_node(node);
+
+	/*
+	 * We touched a (possibly) cold cacheline in the per-cpu queue node;
+	 * attempt the trylock once more in the hope someone let go while we
+	 * weren't watching.
+	 */
+	if (queued_spin_trylock(lock))
+		goto release;
+
+	/*
+	 * Ensure that the initialisation of @node is complete before we
+	 * publish the updated tail via xchg_tail() and potentially link
+	 * @node into the waitqueue via WRITE_ONCE(prev->next, node) below.
+	 */
+	smp_wmb();
+
+	/*
+	 * Publish the updated tail.
+	 * We have already touched the queueing cacheline; don't bother with
+	 * pending stuff.
+	 *
+	 * p,*,* -> n,*,*
+	 */
+	old = xchg_tail(lock, tail);
+	next = NULL;
+
+	/*
+	 * if there was a previous node; link it and wait until reaching the
+	 * head of the waitqueue.
+	 */
+	if (old & _Q_TAIL_MASK) {
+		prev = decode_tail(old);
+
+		/* Link @node into the waitqueue. */
+		WRITE_ONCE(prev->next, node);
+
+		pv_wait_node(node, prev);
+		arch_mcs_spin_lock_contended(&node->locked);
+
+		/*
+		 * While waiting for the MCS lock, the next pointer may have
+		 * been set by another lock waiter. We optimistically load
+		 * the next pointer & prefetch the cacheline for writing
+		 * to reduce latency in the upcoming MCS unlock operation.
+		 */
+		next = READ_ONCE(node->next);
+		if (next)
+			prefetchw(next);
+	}
+
+	/*
+	 * we're at the head of the waitqueue, wait for the owner & pending to
+	 * go away.
+	 *
+	 * *,x,y -> *,0,0
+	 *
+	 * this wait loop must use a load-acquire such that we match the
+	 * store-release that clears the locked bit and create lock
+	 * sequentiality; this is because the set_locked() function below
+	 * does not imply a full barrier.
+	 *
+	 * The PV pv_wait_head_or_lock function, if active, will acquire
+	 * the lock and return a non-zero value. So we have to skip the
+	 * atomic_cond_read_acquire() call. As the next PV queue head hasn't
+	 * been designated yet, there is no way for the locked value to become
+	 * _Q_SLOW_VAL. So both the set_locked() and the
+	 * atomic_cmpxchg_relaxed() calls will be safe.
+	 *
+	 * If PV isn't active, 0 will be returned instead.
+	 *
+	 */
+	if ((val = pv_wait_head_or_lock(lock, node)))
+		goto locked;
+
+	val = atomic_cond_read_acquire(&lock->val, !(VAL & _Q_LOCKED_PENDING_MASK));
+
+locked:
+	/*
+	 * claim the lock:
+	 *
+	 * n,0,0 -> 0,0,1 : lock, uncontended
+	 * *,*,0 -> *,*,1 : lock, contended
+	 *
+	 * If the queue head is the only one in the queue (lock value == tail)
+	 * and nobody is pending, clear the tail code and grab the lock.
+	 * Otherwise, we only need to grab the lock.
+	 */
+
+	/*
+	 * In the PV case we might already have _Q_LOCKED_VAL set, because
+	 * of lock stealing; therefore we must also allow:
+	 *
+	 * n,0,1 -> 0,0,1
+	 *
+	 * Note: at this point: (val & _Q_PENDING_MASK) == 0, because of the
+	 *       above wait condition, therefore any concurrent setting of
+	 *       PENDING will make the uncontended transition fail.
+	 */
+	if ((val & _Q_TAIL_MASK) == tail) {
+		if (atomic_try_cmpxchg_relaxed(&lock->val, &val, _Q_LOCKED_VAL))
+			goto release; /* No contention */
+	}
+
+	/*
+	 * Either somebody is queued behind us or _Q_PENDING_VAL got set
+	 * which will then detect the remaining tail and queue behind us
+	 * ensuring we'll see a @next.
+	 */
+	set_locked(lock);
+
+	/*
+	 * contended path; wait for next if not observed yet, release.
+	 */
+	if (!next)
+		next = smp_cond_load_relaxed(&node->next, (VAL));
+
+	arch_mcs_spin_unlock_contended(&next->locked);
+	pv_kick_node(lock, next);
+
+release:
+	trace_contention_end(lock, 0);
+
+	/*
+	 * release the node
+	 */
+	__this_cpu_dec(qnodes[0].mcs.count);
+}
+EXPORT_SYMBOL(queued_spin_lock_slowpath);
+
+/*
+ * Generate the paravirt code for queued_spin_unlock_slowpath().
+ */
+#if !defined(_GEN_PV_LOCK_SLOWPATH) && defined(CONFIG_PARAVIRT_SPINLOCKS)
+#define _GEN_PV_LOCK_SLOWPATH
+
+#undef  pv_enabled
+#define pv_enabled()	true
+
+#undef pv_init_node
+#undef pv_wait_node
+#undef pv_kick_node
+#undef pv_wait_head_or_lock
+
+#undef  queued_spin_lock_slowpath
+#define queued_spin_lock_slowpath	__pv_queued_spin_lock_slowpath
+
+#include "qspinlock_paravirt.h"
+#include "qspinlock.c"
+
+bool nopvspin __initdata;
+static __init int parse_nopvspin(char *arg)
+{
+	nopvspin = true;
+	return 0;
+}
+early_param("nopvspin", parse_nopvspin);
+#endif
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
new file mode 100644
index 000000000..6afc249ce
--- /dev/null
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -0,0 +1,562 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _GEN_PV_LOCK_SLOWPATH
+#error "do not include this file"
+#endif
+
+#include <linux/hash.h>
+#include <linux/memblock.h>
+#include <linux/debug_locks.h>
+
+/*
+ * Implement paravirt qspinlocks; the general idea is to halt the vcpus instead
+ * of spinning them.
+ *
+ * This relies on the architecture to provide two paravirt hypercalls:
+ *
+ *   pv_wait(u8 *ptr, u8 val) -- suspends the vcpu if *ptr == val
+ *   pv_kick(cpu)             -- wakes a suspended vcpu
+ *
+ * Using these we implement __pv_queued_spin_lock_slowpath() and
+ * __pv_queued_spin_unlock() to replace native_queued_spin_lock_slowpath() and
+ * native_queued_spin_unlock().
+ */
+
+#define _Q_SLOW_VAL	(3U << _Q_LOCKED_OFFSET)
+
+/*
+ * Queue Node Adaptive Spinning
+ *
+ * A queue node vCPU will stop spinning if the vCPU in the previous node is
+ * not running. The one lock stealing attempt allowed at slowpath entry
+ * mitigates the slight slowdown for non-overcommitted guest with this
+ * aggressive wait-early mechanism.
+ *
+ * The status of the previous node will be checked at fixed interval
+ * controlled by PV_PREV_CHECK_MASK. This is to ensure that we won't
+ * pound on the cacheline of the previous node too heavily.
+ */
+#define PV_PREV_CHECK_MASK	0xff
+
+/*
+ * Queue node uses: vcpu_running & vcpu_halted.
+ * Queue head uses: vcpu_running & vcpu_hashed.
+ */
+enum vcpu_state {
+	vcpu_running = 0,
+	vcpu_halted,		/* Used only in pv_wait_node */
+	vcpu_hashed,		/* = pv_hash'ed + vcpu_halted */
+};
+
+struct pv_node {
+	struct mcs_spinlock	mcs;
+	int			cpu;
+	u8			state;
+};
+
+/*
+ * Hybrid PV queued/unfair lock
+ *
+ * By replacing the regular queued_spin_trylock() with the function below,
+ * it will be called once when a lock waiter enter the PV slowpath before
+ * being queued.
+ *
+ * The pending bit is set by the queue head vCPU of the MCS wait queue in
+ * pv_wait_head_or_lock() to signal that it is ready to spin on the lock.
+ * When that bit becomes visible to the incoming waiters, no lock stealing
+ * is allowed. The function will return immediately to make the waiters
+ * enter the MCS wait queue. So lock starvation shouldn't happen as long
+ * as the queued mode vCPUs are actively running to set the pending bit
+ * and hence disabling lock stealing.
+ *
+ * When the pending bit isn't set, the lock waiters will stay in the unfair
+ * mode spinning on the lock unless the MCS wait queue is empty. In this
+ * case, the lock waiters will enter the queued mode slowpath trying to
+ * become the queue head and set the pending bit.
+ *
+ * This hybrid PV queued/unfair lock combines the best attributes of a
+ * queued lock (no lock starvation) and an unfair lock (good performance
+ * on not heavily contended locks).
+ */
+#define queued_spin_trylock(l)	pv_hybrid_queued_unfair_trylock(l)
+static inline bool pv_hybrid_queued_unfair_trylock(struct qspinlock *lock)
+{
+	/*
+	 * Stay in unfair lock mode as long as queued mode waiters are
+	 * present in the MCS wait queue but the pending bit isn't set.
+	 */
+	for (;;) {
+		int val = atomic_read(&lock->val);
+
+		if (!(val & _Q_LOCKED_PENDING_MASK) &&
+		   (cmpxchg_acquire(&lock->locked, 0, _Q_LOCKED_VAL) == 0)) {
+			lockevent_inc(pv_lock_stealing);
+			return true;
+		}
+		if (!(val & _Q_TAIL_MASK) || (val & _Q_PENDING_MASK))
+			break;
+
+		cpu_relax();
+	}
+
+	return false;
+}
+
+/*
+ * The pending bit is used by the queue head vCPU to indicate that it
+ * is actively spinning on the lock and no lock stealing is allowed.
+ */
+#if _Q_PENDING_BITS == 8
+static __always_inline void set_pending(struct qspinlock *lock)
+{
+	WRITE_ONCE(lock->pending, 1);
+}
+
+/*
+ * The pending bit check in pv_queued_spin_steal_lock() isn't a memory
+ * barrier. Therefore, an atomic cmpxchg_acquire() is used to acquire the
+ * lock just to be sure that it will get it.
+ */
+static __always_inline int trylock_clear_pending(struct qspinlock *lock)
+{
+	return !READ_ONCE(lock->locked) &&
+	       (cmpxchg_acquire(&lock->locked_pending, _Q_PENDING_VAL,
+				_Q_LOCKED_VAL) == _Q_PENDING_VAL);
+}
+#else /* _Q_PENDING_BITS == 8 */
+static __always_inline void set_pending(struct qspinlock *lock)
+{
+	atomic_or(_Q_PENDING_VAL, &lock->val);
+}
+
+static __always_inline int trylock_clear_pending(struct qspinlock *lock)
+{
+	int val = atomic_read(&lock->val);
+
+	for (;;) {
+		int old, new;
+
+		if (val  & _Q_LOCKED_MASK)
+			break;
+
+		/*
+		 * Try to clear pending bit & set locked bit
+		 */
+		old = val;
+		new = (val & ~_Q_PENDING_MASK) | _Q_LOCKED_VAL;
+		val = atomic_cmpxchg_acquire(&lock->val, old, new);
+
+		if (val == old)
+			return 1;
+	}
+	return 0;
+}
+#endif /* _Q_PENDING_BITS == 8 */
+
+/*
+ * Lock and MCS node addresses hash table for fast lookup
+ *
+ * Hashing is done on a per-cacheline basis to minimize the need to access
+ * more than one cacheline.
+ *
+ * Dynamically allocate a hash table big enough to hold at least 4X the
+ * number of possible cpus in the system. Allocation is done on page
+ * granularity. So the minimum number of hash buckets should be at least
+ * 256 (64-bit) or 512 (32-bit) to fully utilize a 4k page.
+ *
+ * Since we should not be holding locks from NMI context (very rare indeed) the
+ * max load factor is 0.75, which is around the point where open addressing
+ * breaks down.
+ *
+ */
+struct pv_hash_entry {
+	struct qspinlock *lock;
+	struct pv_node   *node;
+};
+
+#define PV_HE_PER_LINE	(SMP_CACHE_BYTES / sizeof(struct pv_hash_entry))
+#define PV_HE_MIN	(PAGE_SIZE / sizeof(struct pv_hash_entry))
+
+static struct pv_hash_entry *pv_lock_hash;
+static unsigned int pv_lock_hash_bits __read_mostly;
+
+/*
+ * Allocate memory for the PV qspinlock hash buckets
+ *
+ * This function should be called from the paravirt spinlock initialization
+ * routine.
+ */
+void __init __pv_init_lock_hash(void)
+{
+	int pv_hash_size = ALIGN(4 * num_possible_cpus(), PV_HE_PER_LINE);
+
+	if (pv_hash_size < PV_HE_MIN)
+		pv_hash_size = PV_HE_MIN;
+
+	/*
+	 * Allocate space from bootmem which should be page-size aligned
+	 * and hence cacheline aligned.
+	 */
+	pv_lock_hash = alloc_large_system_hash("PV qspinlock",
+					       sizeof(struct pv_hash_entry),
+					       pv_hash_size, 0,
+					       HASH_EARLY | HASH_ZERO,
+					       &pv_lock_hash_bits, NULL,
+					       pv_hash_size, pv_hash_size);
+}
+
+#define for_each_hash_entry(he, offset, hash)						\
+	for (hash &= ~(PV_HE_PER_LINE - 1), he = &pv_lock_hash[hash], offset = 0;	\
+	     offset < (1 << pv_lock_hash_bits);						\
+	     offset++, he = &pv_lock_hash[(hash + offset) & ((1 << pv_lock_hash_bits) - 1)])
+
+static struct qspinlock **pv_hash(struct qspinlock *lock, struct pv_node *node)
+{
+	unsigned long offset, hash = hash_ptr(lock, pv_lock_hash_bits);
+	struct pv_hash_entry *he;
+	int hopcnt = 0;
+
+	for_each_hash_entry(he, offset, hash) {
+		hopcnt++;
+		if (!cmpxchg(&he->lock, NULL, lock)) {
+			WRITE_ONCE(he->node, node);
+			lockevent_pv_hop(hopcnt);
+			return &he->lock;
+		}
+	}
+	/*
+	 * Hard assume there is a free entry for us.
+	 *
+	 * This is guaranteed by ensuring every blocked lock only ever consumes
+	 * a single entry, and since we only have 4 nesting levels per CPU
+	 * and allocated 4*nr_possible_cpus(), this must be so.
+	 *
+	 * The single entry is guaranteed by having the lock owner unhash
+	 * before it releases.
+	 */
+	BUG();
+}
+
+static struct pv_node *pv_unhash(struct qspinlock *lock)
+{
+	unsigned long offset, hash = hash_ptr(lock, pv_lock_hash_bits);
+	struct pv_hash_entry *he;
+	struct pv_node *node;
+
+	for_each_hash_entry(he, offset, hash) {
+		if (READ_ONCE(he->lock) == lock) {
+			node = READ_ONCE(he->node);
+			WRITE_ONCE(he->lock, NULL);
+			return node;
+		}
+	}
+	/*
+	 * Hard assume we'll find an entry.
+	 *
+	 * This guarantees a limited lookup time and is itself guaranteed by
+	 * having the lock owner do the unhash -- IFF the unlock sees the
+	 * SLOW flag, there MUST be a hash entry.
+	 */
+	BUG();
+}
+
+/*
+ * Return true if when it is time to check the previous node which is not
+ * in a running state.
+ */
+static inline bool
+pv_wait_early(struct pv_node *prev, int loop)
+{
+	if ((loop & PV_PREV_CHECK_MASK) != 0)
+		return false;
+
+	return READ_ONCE(prev->state) != vcpu_running;
+}
+
+/*
+ * Initialize the PV part of the mcs_spinlock node.
+ */
+static void pv_init_node(struct mcs_spinlock *node)
+{
+	struct pv_node *pn = (struct pv_node *)node;
+
+	BUILD_BUG_ON(sizeof(struct pv_node) > sizeof(struct qnode));
+
+	pn->cpu = smp_processor_id();
+	pn->state = vcpu_running;
+}
+
+/*
+ * Wait for node->locked to become true, halt the vcpu after a short spin.
+ * pv_kick_node() is used to set _Q_SLOW_VAL and fill in hash table on its
+ * behalf.
+ */
+static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev)
+{
+	struct pv_node *pn = (struct pv_node *)node;
+	struct pv_node *pp = (struct pv_node *)prev;
+	int loop;
+	bool wait_early;
+
+	for (;;) {
+		for (wait_early = false, loop = SPIN_THRESHOLD; loop; loop--) {
+			if (READ_ONCE(node->locked))
+				return;
+			if (pv_wait_early(pp, loop)) {
+				wait_early = true;
+				break;
+			}
+			cpu_relax();
+		}
+
+		/*
+		 * Order pn->state vs pn->locked thusly:
+		 *
+		 * [S] pn->state = vcpu_halted	  [S] next->locked = 1
+		 *     MB			      MB
+		 * [L] pn->locked		[RmW] pn->state = vcpu_hashed
+		 *
+		 * Matches the cmpxchg() from pv_kick_node().
+		 */
+		smp_store_mb(pn->state, vcpu_halted);
+
+		if (!READ_ONCE(node->locked)) {
+			lockevent_inc(pv_wait_node);
+			lockevent_cond_inc(pv_wait_early, wait_early);
+			pv_wait(&pn->state, vcpu_halted);
+		}
+
+		/*
+		 * If pv_kick_node() changed us to vcpu_hashed, retain that
+		 * value so that pv_wait_head_or_lock() knows to not also try
+		 * to hash this lock.
+		 */
+		cmpxchg(&pn->state, vcpu_halted, vcpu_running);
+
+		/*
+		 * If the locked flag is still not set after wakeup, it is a
+		 * spurious wakeup and the vCPU should wait again. However,
+		 * there is a pretty high overhead for CPU halting and kicking.
+		 * So it is better to spin for a while in the hope that the
+		 * MCS lock will be released soon.
+		 */
+		lockevent_cond_inc(pv_spurious_wakeup,
+				  !READ_ONCE(node->locked));
+	}
+
+	/*
+	 * By now our node->locked should be 1 and our caller will not actually
+	 * spin-wait for it. We do however rely on our caller to do a
+	 * load-acquire for us.
+	 */
+}
+
+/*
+ * Called after setting next->locked = 1 when we're the lock owner.
+ *
+ * Instead of waking the waiters stuck in pv_wait_node() advance their state
+ * such that they're waiting in pv_wait_head_or_lock(), this avoids a
+ * wake/sleep cycle.
+ */
+static void pv_kick_node(struct qspinlock *lock, struct mcs_spinlock *node)
+{
+	struct pv_node *pn = (struct pv_node *)node;
+
+	/*
+	 * If the vCPU is indeed halted, advance its state to match that of
+	 * pv_wait_node(). If OTOH this fails, the vCPU was running and will
+	 * observe its next->locked value and advance itself.
+	 *
+	 * Matches with smp_store_mb() and cmpxchg() in pv_wait_node()
+	 *
+	 * The write to next->locked in arch_mcs_spin_unlock_contended()
+	 * must be ordered before the read of pn->state in the cmpxchg()
+	 * below for the code to work correctly. To guarantee full ordering
+	 * irrespective of the success or failure of the cmpxchg(),
+	 * a relaxed version with explicit barrier is used. The control
+	 * dependency will order the reading of pn->state before any
+	 * subsequent writes.
+	 */
+	smp_mb__before_atomic();
+	if (cmpxchg_relaxed(&pn->state, vcpu_halted, vcpu_hashed)
+	    != vcpu_halted)
+		return;
+
+	/*
+	 * Put the lock into the hash table and set the _Q_SLOW_VAL.
+	 *
+	 * As this is the same vCPU that will check the _Q_SLOW_VAL value and
+	 * the hash table later on at unlock time, no atomic instruction is
+	 * needed.
+	 */
+	WRITE_ONCE(lock->locked, _Q_SLOW_VAL);
+	(void)pv_hash(lock, pn);
+}
+
+/*
+ * Wait for l->locked to become clear and acquire the lock;
+ * halt the vcpu after a short spin.
+ * __pv_queued_spin_unlock() will wake us.
+ *
+ * The current value of the lock will be returned for additional processing.
+ */
+static u32
+pv_wait_head_or_lock(struct qspinlock *lock, struct mcs_spinlock *node)
+{
+	struct pv_node *pn = (struct pv_node *)node;
+	struct qspinlock **lp = NULL;
+	int waitcnt = 0;
+	int loop;
+
+	/*
+	 * If pv_kick_node() already advanced our state, we don't need to
+	 * insert ourselves into the hash table anymore.
+	 */
+	if (READ_ONCE(pn->state) == vcpu_hashed)
+		lp = (struct qspinlock **)1;
+
+	/*
+	 * Tracking # of slowpath locking operations
+	 */
+	lockevent_inc(lock_slowpath);
+
+	for (;; waitcnt++) {
+		/*
+		 * Set correct vCPU state to be used by queue node wait-early
+		 * mechanism.
+		 */
+		WRITE_ONCE(pn->state, vcpu_running);
+
+		/*
+		 * Set the pending bit in the active lock spinning loop to
+		 * disable lock stealing before attempting to acquire the lock.
+		 */
+		set_pending(lock);
+		for (loop = SPIN_THRESHOLD; loop; loop--) {
+			if (trylock_clear_pending(lock))
+				goto gotlock;
+			cpu_relax();
+		}
+		clear_pending(lock);
+
+
+		if (!lp) { /* ONCE */
+			lp = pv_hash(lock, pn);
+
+			/*
+			 * We must hash before setting _Q_SLOW_VAL, such that
+			 * when we observe _Q_SLOW_VAL in __pv_queued_spin_unlock()
+			 * we'll be sure to be able to observe our hash entry.
+			 *
+			 *   [S] <hash>                 [Rmw] l->locked == _Q_SLOW_VAL
+			 *       MB                           RMB
+			 * [RmW] l->locked = _Q_SLOW_VAL  [L] <unhash>
+			 *
+			 * Matches the smp_rmb() in __pv_queued_spin_unlock().
+			 */
+			if (xchg(&lock->locked, _Q_SLOW_VAL) == 0) {
+				/*
+				 * The lock was free and now we own the lock.
+				 * Change the lock value back to _Q_LOCKED_VAL
+				 * and unhash the table.
+				 */
+				WRITE_ONCE(lock->locked, _Q_LOCKED_VAL);
+				WRITE_ONCE(*lp, NULL);
+				goto gotlock;
+			}
+		}
+		WRITE_ONCE(pn->state, vcpu_hashed);
+		lockevent_inc(pv_wait_head);
+		lockevent_cond_inc(pv_wait_again, waitcnt);
+		pv_wait(&lock->locked, _Q_SLOW_VAL);
+
+		/*
+		 * Because of lock stealing, the queue head vCPU may not be
+		 * able to acquire the lock before it has to wait again.
+		 */
+	}
+
+	/*
+	 * The cmpxchg() or xchg() call before coming here provides the
+	 * acquire semantics for locking. The dummy ORing of _Q_LOCKED_VAL
+	 * here is to indicate to the compiler that the value will always
+	 * be nozero to enable better code optimization.
+	 */
+gotlock:
+	return (u32)(atomic_read(&lock->val) | _Q_LOCKED_VAL);
+}
+
+/*
+ * PV versions of the unlock fastpath and slowpath functions to be used
+ * instead of queued_spin_unlock().
+ */
+__visible __lockfunc void
+__pv_queued_spin_unlock_slowpath(struct qspinlock *lock, u8 locked)
+{
+	struct pv_node *node;
+
+	if (unlikely(locked != _Q_SLOW_VAL)) {
+		WARN(!debug_locks_silent,
+		     "pvqspinlock: lock 0x%lx has corrupted value 0x%x!\n",
+		     (unsigned long)lock, atomic_read(&lock->val));
+		return;
+	}
+
+	/*
+	 * A failed cmpxchg doesn't provide any memory-ordering guarantees,
+	 * so we need a barrier to order the read of the node data in
+	 * pv_unhash *after* we've read the lock being _Q_SLOW_VAL.
+	 *
+	 * Matches the cmpxchg() in pv_wait_head_or_lock() setting _Q_SLOW_VAL.
+	 */
+	smp_rmb();
+
+	/*
+	 * Since the above failed to release, this must be the SLOW path.
+	 * Therefore start by looking up the blocked node and unhashing it.
+	 */
+	node = pv_unhash(lock);
+
+	/*
+	 * Now that we have a reference to the (likely) blocked pv_node,
+	 * release the lock.
+	 */
+	smp_store_release(&lock->locked, 0);
+
+	/*
+	 * At this point the memory pointed at by lock can be freed/reused,
+	 * however we can still use the pv_node to kick the CPU.
+	 * The other vCPU may not really be halted, but kicking an active
+	 * vCPU is harmless other than the additional latency in completing
+	 * the unlock.
+	 */
+	lockevent_inc(pv_kick_unlock);
+	pv_kick(node->cpu);
+}
+
+/*
+ * Include the architecture specific callee-save thunk of the
+ * __pv_queued_spin_unlock(). This thunk is put together with
+ * __pv_queued_spin_unlock() to make the callee-save thunk and the real unlock
+ * function close to each other sharing consecutive instruction cachelines.
+ * Alternatively, architecture specific version of __pv_queued_spin_unlock()
+ * can be defined.
+ */
+#include <asm/qspinlock_paravirt.h>
+
+#ifndef __pv_queued_spin_unlock
+__visible __lockfunc void __pv_queued_spin_unlock(struct qspinlock *lock)
+{
+	u8 locked;
+
+	/*
+	 * We must not unlock if SLOW, because in that case we must first
+	 * unhash. Otherwise it would be possible to have multiple @lock
+	 * entries, which would be BAD.
+	 */
+	locked = cmpxchg_release(&lock->locked, _Q_LOCKED_VAL, 0);
+	if (likely(locked == _Q_LOCKED_VAL))
+		return;
+
+	__pv_queued_spin_unlock_slowpath(lock, locked);
+}
+#endif /* __pv_queued_spin_unlock */
diff --git a/kernel/locking/qspinlock_stat.h b/kernel/locking/qspinlock_stat.h
new file mode 100644
index 000000000..e625bb410
--- /dev/null
+++ b/kernel/locking/qspinlock_stat.h
@@ -0,0 +1,142 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *
+ * Authors: Waiman Long <longman@redhat.com>
+ */
+
+#include "lock_events.h"
+
+#ifdef CONFIG_LOCK_EVENT_COUNTS
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+/*
+ * Collect pvqspinlock locking event counts
+ */
+#include <linux/sched.h>
+#include <linux/sched/clock.h>
+#include <linux/fs.h>
+
+#define EVENT_COUNT(ev)	lockevents[LOCKEVENT_ ## ev]
+
+/*
+ * PV specific per-cpu counter
+ */
+static DEFINE_PER_CPU(u64, pv_kick_time);
+
+/*
+ * Function to read and return the PV qspinlock counts.
+ *
+ * The following counters are handled specially:
+ * 1. pv_latency_kick
+ *    Average kick latency (ns) = pv_latency_kick/pv_kick_unlock
+ * 2. pv_latency_wake
+ *    Average wake latency (ns) = pv_latency_wake/pv_kick_wake
+ * 3. pv_hash_hops
+ *    Average hops/hash = pv_hash_hops/pv_kick_unlock
+ */
+ssize_t lockevent_read(struct file *file, char __user *user_buf,
+		       size_t count, loff_t *ppos)
+{
+	char buf[64];
+	int cpu, id, len;
+	u64 sum = 0, kicks = 0;
+
+	/*
+	 * Get the counter ID stored in file->f_inode->i_private
+	 */
+	id = (long)file_inode(file)->i_private;
+
+	if (id >= lockevent_num)
+		return -EBADF;
+
+	for_each_possible_cpu(cpu) {
+		sum += per_cpu(lockevents[id], cpu);
+		/*
+		 * Need to sum additional counters for some of them
+		 */
+		switch (id) {
+
+		case LOCKEVENT_pv_latency_kick:
+		case LOCKEVENT_pv_hash_hops:
+			kicks += per_cpu(EVENT_COUNT(pv_kick_unlock), cpu);
+			break;
+
+		case LOCKEVENT_pv_latency_wake:
+			kicks += per_cpu(EVENT_COUNT(pv_kick_wake), cpu);
+			break;
+		}
+	}
+
+	if (id == LOCKEVENT_pv_hash_hops) {
+		u64 frac = 0;
+
+		if (kicks) {
+			frac = 100ULL * do_div(sum, kicks);
+			frac = DIV_ROUND_CLOSEST_ULL(frac, kicks);
+		}
+
+		/*
+		 * Return a X.XX decimal number
+		 */
+		len = snprintf(buf, sizeof(buf) - 1, "%llu.%02llu\n",
+			       sum, frac);
+	} else {
+		/*
+		 * Round to the nearest ns
+		 */
+		if ((id == LOCKEVENT_pv_latency_kick) ||
+		    (id == LOCKEVENT_pv_latency_wake)) {
+			if (kicks)
+				sum = DIV_ROUND_CLOSEST_ULL(sum, kicks);
+		}
+		len = snprintf(buf, sizeof(buf) - 1, "%llu\n", sum);
+	}
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+/*
+ * PV hash hop count
+ */
+static inline void lockevent_pv_hop(int hopcnt)
+{
+	this_cpu_add(EVENT_COUNT(pv_hash_hops), hopcnt);
+}
+
+/*
+ * Replacement function for pv_kick()
+ */
+static inline void __pv_kick(int cpu)
+{
+	u64 start = sched_clock();
+
+	per_cpu(pv_kick_time, cpu) = start;
+	pv_kick(cpu);
+	this_cpu_add(EVENT_COUNT(pv_latency_kick), sched_clock() - start);
+}
+
+/*
+ * Replacement function for pv_wait()
+ */
+static inline void __pv_wait(u8 *ptr, u8 val)
+{
+	u64 *pkick_time = this_cpu_ptr(&pv_kick_time);
+
+	*pkick_time = 0;
+	pv_wait(ptr, val);
+	if (*pkick_time) {
+		this_cpu_add(EVENT_COUNT(pv_latency_wake),
+			     sched_clock() - *pkick_time);
+		lockevent_inc(pv_kick_wake);
+	}
+}
+
+#define pv_kick(c)	__pv_kick(c)
+#define pv_wait(p, v)	__pv_wait(p, v)
+
+#endif /* CONFIG_PARAVIRT_SPINLOCKS */
+
+#else /* CONFIG_LOCK_EVENT_COUNTS */
+
+static inline void lockevent_pv_hop(int hopcnt)	{ }
+
+#endif /* CONFIG_LOCK_EVENT_COUNTS */
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
new file mode 100644
index 000000000..21db0df0e
--- /dev/null
+++ b/kernel/locking/rtmutex.c
@@ -0,0 +1,1833 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * RT-Mutexes: simple blocking mutual exclusion locks with PI support
+ *
+ * started by Ingo Molnar and Thomas Gleixner.
+ *
+ *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *  Copyright (C) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *  Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt
+ *  Copyright (C) 2006 Esben Nielsen
+ * Adaptive Spinlocks:
+ *  Copyright (C) 2008 Novell, Inc., Gregory Haskins, Sven Dietrich,
+ *				     and Peter Morreale,
+ * Adaptive Spinlocks simplification:
+ *  Copyright (C) 2008 Red Hat, Inc., Steven Rostedt <srostedt@redhat.com>
+ *
+ *  See Documentation/locking/rt-mutex-design.rst for details.
+ */
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/deadline.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/rt.h>
+#include <linux/sched/wake_q.h>
+#include <linux/ww_mutex.h>
+
+#include <trace/events/lock.h>
+
+#include "rtmutex_common.h"
+
+#ifndef WW_RT
+# define build_ww_mutex()	(false)
+# define ww_container_of(rtm)	NULL
+
+static inline int __ww_mutex_add_waiter(struct rt_mutex_waiter *waiter,
+					struct rt_mutex *lock,
+					struct ww_acquire_ctx *ww_ctx)
+{
+	return 0;
+}
+
+static inline void __ww_mutex_check_waiters(struct rt_mutex *lock,
+					    struct ww_acquire_ctx *ww_ctx)
+{
+}
+
+static inline void ww_mutex_lock_acquired(struct ww_mutex *lock,
+					  struct ww_acquire_ctx *ww_ctx)
+{
+}
+
+static inline int __ww_mutex_check_kill(struct rt_mutex *lock,
+					struct rt_mutex_waiter *waiter,
+					struct ww_acquire_ctx *ww_ctx)
+{
+	return 0;
+}
+
+#else
+# define build_ww_mutex()	(true)
+# define ww_container_of(rtm)	container_of(rtm, struct ww_mutex, base)
+# include "ww_mutex.h"
+#endif
+
+/*
+ * lock->owner state tracking:
+ *
+ * lock->owner holds the task_struct pointer of the owner. Bit 0
+ * is used to keep track of the "lock has waiters" state.
+ *
+ * owner	bit0
+ * NULL		0	lock is free (fast acquire possible)
+ * NULL		1	lock is free and has waiters and the top waiter
+ *				is going to take the lock*
+ * taskpointer	0	lock is held (fast release possible)
+ * taskpointer	1	lock is held and has waiters**
+ *
+ * The fast atomic compare exchange based acquire and release is only
+ * possible when bit 0 of lock->owner is 0.
+ *
+ * (*) It also can be a transitional state when grabbing the lock
+ * with ->wait_lock is held. To prevent any fast path cmpxchg to the lock,
+ * we need to set the bit0 before looking at the lock, and the owner may be
+ * NULL in this small time, hence this can be a transitional state.
+ *
+ * (**) There is a small time when bit 0 is set but there are no
+ * waiters. This can happen when grabbing the lock in the slow path.
+ * To prevent a cmpxchg of the owner releasing the lock, we need to
+ * set this bit before looking at the lock.
+ */
+
+static __always_inline struct task_struct *
+rt_mutex_owner_encode(struct rt_mutex_base *lock, struct task_struct *owner)
+{
+	unsigned long val = (unsigned long)owner;
+
+	if (rt_mutex_has_waiters(lock))
+		val |= RT_MUTEX_HAS_WAITERS;
+
+	return (struct task_struct *)val;
+}
+
+static __always_inline void
+rt_mutex_set_owner(struct rt_mutex_base *lock, struct task_struct *owner)
+{
+	/*
+	 * lock->wait_lock is held but explicit acquire semantics are needed
+	 * for a new lock owner so WRITE_ONCE is insufficient.
+	 */
+	xchg_acquire(&lock->owner, rt_mutex_owner_encode(lock, owner));
+}
+
+static __always_inline void rt_mutex_clear_owner(struct rt_mutex_base *lock)
+{
+	/* lock->wait_lock is held so the unlock provides release semantics. */
+	WRITE_ONCE(lock->owner, rt_mutex_owner_encode(lock, NULL));
+}
+
+static __always_inline void clear_rt_mutex_waiters(struct rt_mutex_base *lock)
+{
+	lock->owner = (struct task_struct *)
+			((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS);
+}
+
+static __always_inline void
+fixup_rt_mutex_waiters(struct rt_mutex_base *lock, bool acquire_lock)
+{
+	unsigned long owner, *p = (unsigned long *) &lock->owner;
+
+	if (rt_mutex_has_waiters(lock))
+		return;
+
+	/*
+	 * The rbtree has no waiters enqueued, now make sure that the
+	 * lock->owner still has the waiters bit set, otherwise the
+	 * following can happen:
+	 *
+	 * CPU 0	CPU 1		CPU2
+	 * l->owner=T1
+	 *		rt_mutex_lock(l)
+	 *		lock(l->lock)
+	 *		l->owner = T1 | HAS_WAITERS;
+	 *		enqueue(T2)
+	 *		boost()
+	 *		  unlock(l->lock)
+	 *		block()
+	 *
+	 *				rt_mutex_lock(l)
+	 *				lock(l->lock)
+	 *				l->owner = T1 | HAS_WAITERS;
+	 *				enqueue(T3)
+	 *				boost()
+	 *				  unlock(l->lock)
+	 *				block()
+	 *		signal(->T2)	signal(->T3)
+	 *		lock(l->lock)
+	 *		dequeue(T2)
+	 *		deboost()
+	 *		  unlock(l->lock)
+	 *				lock(l->lock)
+	 *				dequeue(T3)
+	 *				 ==> wait list is empty
+	 *				deboost()
+	 *				 unlock(l->lock)
+	 *		lock(l->lock)
+	 *		fixup_rt_mutex_waiters()
+	 *		  if (wait_list_empty(l) {
+	 *		    l->owner = owner
+	 *		    owner = l->owner & ~HAS_WAITERS;
+	 *		      ==> l->owner = T1
+	 *		  }
+	 *				lock(l->lock)
+	 * rt_mutex_unlock(l)		fixup_rt_mutex_waiters()
+	 *				  if (wait_list_empty(l) {
+	 *				    owner = l->owner & ~HAS_WAITERS;
+	 * cmpxchg(l->owner, T1, NULL)
+	 *  ===> Success (l->owner = NULL)
+	 *
+	 *				    l->owner = owner
+	 *				      ==> l->owner = T1
+	 *				  }
+	 *
+	 * With the check for the waiter bit in place T3 on CPU2 will not
+	 * overwrite. All tasks fiddling with the waiters bit are
+	 * serialized by l->lock, so nothing else can modify the waiters
+	 * bit. If the bit is set then nothing can change l->owner either
+	 * so the simple RMW is safe. The cmpxchg() will simply fail if it
+	 * happens in the middle of the RMW because the waiters bit is
+	 * still set.
+	 */
+	owner = READ_ONCE(*p);
+	if (owner & RT_MUTEX_HAS_WAITERS) {
+		/*
+		 * See rt_mutex_set_owner() and rt_mutex_clear_owner() on
+		 * why xchg_acquire() is used for updating owner for
+		 * locking and WRITE_ONCE() for unlocking.
+		 *
+		 * WRITE_ONCE() would work for the acquire case too, but
+		 * in case that the lock acquisition failed it might
+		 * force other lockers into the slow path unnecessarily.
+		 */
+		if (acquire_lock)
+			xchg_acquire(p, owner & ~RT_MUTEX_HAS_WAITERS);
+		else
+			WRITE_ONCE(*p, owner & ~RT_MUTEX_HAS_WAITERS);
+	}
+}
+
+/*
+ * We can speed up the acquire/release, if there's no debugging state to be
+ * set up.
+ */
+#ifndef CONFIG_DEBUG_RT_MUTEXES
+static __always_inline bool rt_mutex_cmpxchg_acquire(struct rt_mutex_base *lock,
+						     struct task_struct *old,
+						     struct task_struct *new)
+{
+	return try_cmpxchg_acquire(&lock->owner, &old, new);
+}
+
+static __always_inline bool rt_mutex_cmpxchg_release(struct rt_mutex_base *lock,
+						     struct task_struct *old,
+						     struct task_struct *new)
+{
+	return try_cmpxchg_release(&lock->owner, &old, new);
+}
+
+/*
+ * Callers must hold the ->wait_lock -- which is the whole purpose as we force
+ * all future threads that attempt to [Rmw] the lock to the slowpath. As such
+ * relaxed semantics suffice.
+ */
+static __always_inline void mark_rt_mutex_waiters(struct rt_mutex_base *lock)
+{
+	unsigned long owner, *p = (unsigned long *) &lock->owner;
+
+	do {
+		owner = *p;
+	} while (cmpxchg_relaxed(p, owner,
+				 owner | RT_MUTEX_HAS_WAITERS) != owner);
+
+	/*
+	 * The cmpxchg loop above is relaxed to avoid back-to-back ACQUIRE
+	 * operations in the event of contention. Ensure the successful
+	 * cmpxchg is visible.
+	 */
+	smp_mb__after_atomic();
+}
+
+/*
+ * Safe fastpath aware unlock:
+ * 1) Clear the waiters bit
+ * 2) Drop lock->wait_lock
+ * 3) Try to unlock the lock with cmpxchg
+ */
+static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex_base *lock,
+						 unsigned long flags)
+	__releases(lock->wait_lock)
+{
+	struct task_struct *owner = rt_mutex_owner(lock);
+
+	clear_rt_mutex_waiters(lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+	/*
+	 * If a new waiter comes in between the unlock and the cmpxchg
+	 * we have two situations:
+	 *
+	 * unlock(wait_lock);
+	 *					lock(wait_lock);
+	 * cmpxchg(p, owner, 0) == owner
+	 *					mark_rt_mutex_waiters(lock);
+	 *					acquire(lock);
+	 * or:
+	 *
+	 * unlock(wait_lock);
+	 *					lock(wait_lock);
+	 *					mark_rt_mutex_waiters(lock);
+	 *
+	 * cmpxchg(p, owner, 0) != owner
+	 *					enqueue_waiter();
+	 *					unlock(wait_lock);
+	 * lock(wait_lock);
+	 * wake waiter();
+	 * unlock(wait_lock);
+	 *					lock(wait_lock);
+	 *					acquire(lock);
+	 */
+	return rt_mutex_cmpxchg_release(lock, owner, NULL);
+}
+
+#else
+static __always_inline bool rt_mutex_cmpxchg_acquire(struct rt_mutex_base *lock,
+						     struct task_struct *old,
+						     struct task_struct *new)
+{
+	return false;
+
+}
+
+static __always_inline bool rt_mutex_cmpxchg_release(struct rt_mutex_base *lock,
+						     struct task_struct *old,
+						     struct task_struct *new)
+{
+	return false;
+}
+
+static __always_inline void mark_rt_mutex_waiters(struct rt_mutex_base *lock)
+{
+	lock->owner = (struct task_struct *)
+			((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS);
+}
+
+/*
+ * Simple slow path only version: lock->owner is protected by lock->wait_lock.
+ */
+static __always_inline bool unlock_rt_mutex_safe(struct rt_mutex_base *lock,
+						 unsigned long flags)
+	__releases(lock->wait_lock)
+{
+	lock->owner = NULL;
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+	return true;
+}
+#endif
+
+static __always_inline int __waiter_prio(struct task_struct *task)
+{
+	int prio = task->prio;
+
+	if (!rt_prio(prio))
+		return DEFAULT_PRIO;
+
+	return prio;
+}
+
+/*
+ * Update the waiter->tree copy of the sort keys.
+ */
+static __always_inline void
+waiter_update_prio(struct rt_mutex_waiter *waiter, struct task_struct *task)
+{
+	lockdep_assert_held(&waiter->lock->wait_lock);
+	lockdep_assert(RB_EMPTY_NODE(&waiter->tree.entry));
+
+	waiter->tree.prio = __waiter_prio(task);
+	waiter->tree.deadline = task->dl.deadline;
+}
+
+/*
+ * Update the waiter->pi_tree copy of the sort keys (from the tree copy).
+ */
+static __always_inline void
+waiter_clone_prio(struct rt_mutex_waiter *waiter, struct task_struct *task)
+{
+	lockdep_assert_held(&waiter->lock->wait_lock);
+	lockdep_assert_held(&task->pi_lock);
+	lockdep_assert(RB_EMPTY_NODE(&waiter->pi_tree.entry));
+
+	waiter->pi_tree.prio = waiter->tree.prio;
+	waiter->pi_tree.deadline = waiter->tree.deadline;
+}
+
+/*
+ * Only use with rt_waiter_node_{less,equal}()
+ */
+#define task_to_waiter_node(p)	\
+	&(struct rt_waiter_node){ .prio = __waiter_prio(p), .deadline = (p)->dl.deadline }
+#define task_to_waiter(p)	\
+	&(struct rt_mutex_waiter){ .tree = *task_to_waiter_node(p) }
+
+static __always_inline int rt_waiter_node_less(struct rt_waiter_node *left,
+					       struct rt_waiter_node *right)
+{
+	if (left->prio < right->prio)
+		return 1;
+
+	/*
+	 * If both waiters have dl_prio(), we check the deadlines of the
+	 * associated tasks.
+	 * If left waiter has a dl_prio(), and we didn't return 1 above,
+	 * then right waiter has a dl_prio() too.
+	 */
+	if (dl_prio(left->prio))
+		return dl_time_before(left->deadline, right->deadline);
+
+	return 0;
+}
+
+static __always_inline int rt_waiter_node_equal(struct rt_waiter_node *left,
+						 struct rt_waiter_node *right)
+{
+	if (left->prio != right->prio)
+		return 0;
+
+	/*
+	 * If both waiters have dl_prio(), we check the deadlines of the
+	 * associated tasks.
+	 * If left waiter has a dl_prio(), and we didn't return 0 above,
+	 * then right waiter has a dl_prio() too.
+	 */
+	if (dl_prio(left->prio))
+		return left->deadline == right->deadline;
+
+	return 1;
+}
+
+static inline bool rt_mutex_steal(struct rt_mutex_waiter *waiter,
+				  struct rt_mutex_waiter *top_waiter)
+{
+	if (rt_waiter_node_less(&waiter->tree, &top_waiter->tree))
+		return true;
+
+#ifdef RT_MUTEX_BUILD_SPINLOCKS
+	/*
+	 * Note that RT tasks are excluded from same priority (lateral)
+	 * steals to prevent the introduction of an unbounded latency.
+	 */
+	if (rt_prio(waiter->tree.prio) || dl_prio(waiter->tree.prio))
+		return false;
+
+	return rt_waiter_node_equal(&waiter->tree, &top_waiter->tree);
+#else
+	return false;
+#endif
+}
+
+#define __node_2_waiter(node) \
+	rb_entry((node), struct rt_mutex_waiter, tree.entry)
+
+static __always_inline bool __waiter_less(struct rb_node *a, const struct rb_node *b)
+{
+	struct rt_mutex_waiter *aw = __node_2_waiter(a);
+	struct rt_mutex_waiter *bw = __node_2_waiter(b);
+
+	if (rt_waiter_node_less(&aw->tree, &bw->tree))
+		return 1;
+
+	if (!build_ww_mutex())
+		return 0;
+
+	if (rt_waiter_node_less(&bw->tree, &aw->tree))
+		return 0;
+
+	/* NOTE: relies on waiter->ww_ctx being set before insertion */
+	if (aw->ww_ctx) {
+		if (!bw->ww_ctx)
+			return 1;
+
+		return (signed long)(aw->ww_ctx->stamp -
+				     bw->ww_ctx->stamp) < 0;
+	}
+
+	return 0;
+}
+
+static __always_inline void
+rt_mutex_enqueue(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter)
+{
+	lockdep_assert_held(&lock->wait_lock);
+
+	rb_add_cached(&waiter->tree.entry, &lock->waiters, __waiter_less);
+}
+
+static __always_inline void
+rt_mutex_dequeue(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter)
+{
+	lockdep_assert_held(&lock->wait_lock);
+
+	if (RB_EMPTY_NODE(&waiter->tree.entry))
+		return;
+
+	rb_erase_cached(&waiter->tree.entry, &lock->waiters);
+	RB_CLEAR_NODE(&waiter->tree.entry);
+}
+
+#define __node_2_rt_node(node) \
+	rb_entry((node), struct rt_waiter_node, entry)
+
+static __always_inline bool __pi_waiter_less(struct rb_node *a, const struct rb_node *b)
+{
+	return rt_waiter_node_less(__node_2_rt_node(a), __node_2_rt_node(b));
+}
+
+static __always_inline void
+rt_mutex_enqueue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter)
+{
+	lockdep_assert_held(&task->pi_lock);
+
+	rb_add_cached(&waiter->pi_tree.entry, &task->pi_waiters, __pi_waiter_less);
+}
+
+static __always_inline void
+rt_mutex_dequeue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter)
+{
+	lockdep_assert_held(&task->pi_lock);
+
+	if (RB_EMPTY_NODE(&waiter->pi_tree.entry))
+		return;
+
+	rb_erase_cached(&waiter->pi_tree.entry, &task->pi_waiters);
+	RB_CLEAR_NODE(&waiter->pi_tree.entry);
+}
+
+static __always_inline void rt_mutex_adjust_prio(struct rt_mutex_base *lock,
+						 struct task_struct *p)
+{
+	struct task_struct *pi_task = NULL;
+
+	lockdep_assert_held(&lock->wait_lock);
+	lockdep_assert(rt_mutex_owner(lock) == p);
+	lockdep_assert_held(&p->pi_lock);
+
+	if (task_has_pi_waiters(p))
+		pi_task = task_top_pi_waiter(p)->task;
+
+	rt_mutex_setprio(p, pi_task);
+}
+
+/* RT mutex specific wake_q wrappers */
+static __always_inline void rt_mutex_wake_q_add_task(struct rt_wake_q_head *wqh,
+						     struct task_struct *task,
+						     unsigned int wake_state)
+{
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && wake_state == TASK_RTLOCK_WAIT) {
+		if (IS_ENABLED(CONFIG_PROVE_LOCKING))
+			WARN_ON_ONCE(wqh->rtlock_task);
+		get_task_struct(task);
+		wqh->rtlock_task = task;
+	} else {
+		wake_q_add(&wqh->head, task);
+	}
+}
+
+static __always_inline void rt_mutex_wake_q_add(struct rt_wake_q_head *wqh,
+						struct rt_mutex_waiter *w)
+{
+	rt_mutex_wake_q_add_task(wqh, w->task, w->wake_state);
+}
+
+static __always_inline void rt_mutex_wake_up_q(struct rt_wake_q_head *wqh)
+{
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && wqh->rtlock_task) {
+		wake_up_state(wqh->rtlock_task, TASK_RTLOCK_WAIT);
+		put_task_struct(wqh->rtlock_task);
+		wqh->rtlock_task = NULL;
+	}
+
+	if (!wake_q_empty(&wqh->head))
+		wake_up_q(&wqh->head);
+
+	/* Pairs with preempt_disable() in mark_wakeup_next_waiter() */
+	preempt_enable();
+}
+
+/*
+ * Deadlock detection is conditional:
+ *
+ * If CONFIG_DEBUG_RT_MUTEXES=n, deadlock detection is only conducted
+ * if the detect argument is == RT_MUTEX_FULL_CHAINWALK.
+ *
+ * If CONFIG_DEBUG_RT_MUTEXES=y, deadlock detection is always
+ * conducted independent of the detect argument.
+ *
+ * If the waiter argument is NULL this indicates the deboost path and
+ * deadlock detection is disabled independent of the detect argument
+ * and the config settings.
+ */
+static __always_inline bool
+rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
+			      enum rtmutex_chainwalk chwalk)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		return waiter != NULL;
+	return chwalk == RT_MUTEX_FULL_CHAINWALK;
+}
+
+static __always_inline struct rt_mutex_base *task_blocked_on_lock(struct task_struct *p)
+{
+	return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
+}
+
+/*
+ * Adjust the priority chain. Also used for deadlock detection.
+ * Decreases task's usage by one - may thus free the task.
+ *
+ * @task:	the task owning the mutex (owner) for which a chain walk is
+ *		probably needed
+ * @chwalk:	do we have to carry out deadlock detection?
+ * @orig_lock:	the mutex (can be NULL if we are walking the chain to recheck
+ *		things for a task that has just got its priority adjusted, and
+ *		is waiting on a mutex)
+ * @next_lock:	the mutex on which the owner of @orig_lock was blocked before
+ *		we dropped its pi_lock. Is never dereferenced, only used for
+ *		comparison to detect lock chain changes.
+ * @orig_waiter: rt_mutex_waiter struct for the task that has just donated
+ *		its priority to the mutex owner (can be NULL in the case
+ *		depicted above or if the top waiter is gone away and we are
+ *		actually deboosting the owner)
+ * @top_task:	the current top waiter
+ *
+ * Returns 0 or -EDEADLK.
+ *
+ * Chain walk basics and protection scope
+ *
+ * [R] refcount on task
+ * [Pn] task->pi_lock held
+ * [L] rtmutex->wait_lock held
+ *
+ * Normal locking order:
+ *
+ *   rtmutex->wait_lock
+ *     task->pi_lock
+ *
+ * Step	Description				Protected by
+ *	function arguments:
+ *	@task					[R]
+ *	@orig_lock if != NULL			@top_task is blocked on it
+ *	@next_lock				Unprotected. Cannot be
+ *						dereferenced. Only used for
+ *						comparison.
+ *	@orig_waiter if != NULL			@top_task is blocked on it
+ *	@top_task				current, or in case of proxy
+ *						locking protected by calling
+ *						code
+ *	again:
+ *	  loop_sanity_check();
+ *	retry:
+ * [1]	  lock(task->pi_lock);			[R] acquire [P1]
+ * [2]	  waiter = task->pi_blocked_on;		[P1]
+ * [3]	  check_exit_conditions_1();		[P1]
+ * [4]	  lock = waiter->lock;			[P1]
+ * [5]	  if (!try_lock(lock->wait_lock)) {	[P1] try to acquire [L]
+ *	    unlock(task->pi_lock);		release [P1]
+ *	    goto retry;
+ *	  }
+ * [6]	  check_exit_conditions_2();		[P1] + [L]
+ * [7]	  requeue_lock_waiter(lock, waiter);	[P1] + [L]
+ * [8]	  unlock(task->pi_lock);		release [P1]
+ *	  put_task_struct(task);		release [R]
+ * [9]	  check_exit_conditions_3();		[L]
+ * [10]	  task = owner(lock);			[L]
+ *	  get_task_struct(task);		[L] acquire [R]
+ *	  lock(task->pi_lock);			[L] acquire [P2]
+ * [11]	  requeue_pi_waiter(tsk, waiters(lock));[P2] + [L]
+ * [12]	  check_exit_conditions_4();		[P2] + [L]
+ * [13]	  unlock(task->pi_lock);		release [P2]
+ *	  unlock(lock->wait_lock);		release [L]
+ *	  goto again;
+ *
+ * Where P1 is the blocking task and P2 is the lock owner; going up one step
+ * the owner becomes the next blocked task etc..
+ *
+*
+ */
+static int __sched rt_mutex_adjust_prio_chain(struct task_struct *task,
+					      enum rtmutex_chainwalk chwalk,
+					      struct rt_mutex_base *orig_lock,
+					      struct rt_mutex_base *next_lock,
+					      struct rt_mutex_waiter *orig_waiter,
+					      struct task_struct *top_task)
+{
+	struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
+	struct rt_mutex_waiter *prerequeue_top_waiter;
+	int ret = 0, depth = 0;
+	struct rt_mutex_base *lock;
+	bool detect_deadlock;
+	bool requeue = true;
+
+	detect_deadlock = rt_mutex_cond_detect_deadlock(orig_waiter, chwalk);
+
+	/*
+	 * The (de)boosting is a step by step approach with a lot of
+	 * pitfalls. We want this to be preemptible and we want hold a
+	 * maximum of two locks per step. So we have to check
+	 * carefully whether things change under us.
+	 */
+ again:
+	/*
+	 * We limit the lock chain length for each invocation.
+	 */
+	if (++depth > max_lock_depth) {
+		static int prev_max;
+
+		/*
+		 * Print this only once. If the admin changes the limit,
+		 * print a new message when reaching the limit again.
+		 */
+		if (prev_max != max_lock_depth) {
+			prev_max = max_lock_depth;
+			printk(KERN_WARNING "Maximum lock depth %d reached "
+			       "task: %s (%d)\n", max_lock_depth,
+			       top_task->comm, task_pid_nr(top_task));
+		}
+		put_task_struct(task);
+
+		return -EDEADLK;
+	}
+
+	/*
+	 * We are fully preemptible here and only hold the refcount on
+	 * @task. So everything can have changed under us since the
+	 * caller or our own code below (goto retry/again) dropped all
+	 * locks.
+	 */
+ retry:
+	/*
+	 * [1] Task cannot go away as we did a get_task() before !
+	 */
+	raw_spin_lock_irq(&task->pi_lock);
+
+	/*
+	 * [2] Get the waiter on which @task is blocked on.
+	 */
+	waiter = task->pi_blocked_on;
+
+	/*
+	 * [3] check_exit_conditions_1() protected by task->pi_lock.
+	 */
+
+	/*
+	 * Check whether the end of the boosting chain has been
+	 * reached or the state of the chain has changed while we
+	 * dropped the locks.
+	 */
+	if (!waiter)
+		goto out_unlock_pi;
+
+	/*
+	 * Check the orig_waiter state. After we dropped the locks,
+	 * the previous owner of the lock might have released the lock.
+	 */
+	if (orig_waiter && !rt_mutex_owner(orig_lock))
+		goto out_unlock_pi;
+
+	/*
+	 * We dropped all locks after taking a refcount on @task, so
+	 * the task might have moved on in the lock chain or even left
+	 * the chain completely and blocks now on an unrelated lock or
+	 * on @orig_lock.
+	 *
+	 * We stored the lock on which @task was blocked in @next_lock,
+	 * so we can detect the chain change.
+	 */
+	if (next_lock != waiter->lock)
+		goto out_unlock_pi;
+
+	/*
+	 * There could be 'spurious' loops in the lock graph due to ww_mutex,
+	 * consider:
+	 *
+	 *   P1: A, ww_A, ww_B
+	 *   P2: ww_B, ww_A
+	 *   P3: A
+	 *
+	 * P3 should not return -EDEADLK because it gets trapped in the cycle
+	 * created by P1 and P2 (which will resolve -- and runs into
+	 * max_lock_depth above). Therefore disable detect_deadlock such that
+	 * the below termination condition can trigger once all relevant tasks
+	 * are boosted.
+	 *
+	 * Even when we start with ww_mutex we can disable deadlock detection,
+	 * since we would supress a ww_mutex induced deadlock at [6] anyway.
+	 * Supressing it here however is not sufficient since we might still
+	 * hit [6] due to adjustment driven iteration.
+	 *
+	 * NOTE: if someone were to create a deadlock between 2 ww_classes we'd
+	 * utterly fail to report it; lockdep should.
+	 */
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && waiter->ww_ctx && detect_deadlock)
+		detect_deadlock = false;
+
+	/*
+	 * Drop out, when the task has no waiters. Note,
+	 * top_waiter can be NULL, when we are in the deboosting
+	 * mode!
+	 */
+	if (top_waiter) {
+		if (!task_has_pi_waiters(task))
+			goto out_unlock_pi;
+		/*
+		 * If deadlock detection is off, we stop here if we
+		 * are not the top pi waiter of the task. If deadlock
+		 * detection is enabled we continue, but stop the
+		 * requeueing in the chain walk.
+		 */
+		if (top_waiter != task_top_pi_waiter(task)) {
+			if (!detect_deadlock)
+				goto out_unlock_pi;
+			else
+				requeue = false;
+		}
+	}
+
+	/*
+	 * If the waiter priority is the same as the task priority
+	 * then there is no further priority adjustment necessary.  If
+	 * deadlock detection is off, we stop the chain walk. If its
+	 * enabled we continue, but stop the requeueing in the chain
+	 * walk.
+	 */
+	if (rt_waiter_node_equal(&waiter->tree, task_to_waiter_node(task))) {
+		if (!detect_deadlock)
+			goto out_unlock_pi;
+		else
+			requeue = false;
+	}
+
+	/*
+	 * [4] Get the next lock; per holding task->pi_lock we can't unblock
+	 * and guarantee @lock's existence.
+	 */
+	lock = waiter->lock;
+	/*
+	 * [5] We need to trylock here as we are holding task->pi_lock,
+	 * which is the reverse lock order versus the other rtmutex
+	 * operations.
+	 *
+	 * Per the above, holding task->pi_lock guarantees lock exists, so
+	 * inverting this lock order is infeasible from a life-time
+	 * perspective.
+	 */
+	if (!raw_spin_trylock(&lock->wait_lock)) {
+		raw_spin_unlock_irq(&task->pi_lock);
+		cpu_relax();
+		goto retry;
+	}
+
+	/*
+	 * [6] check_exit_conditions_2() protected by task->pi_lock and
+	 * lock->wait_lock.
+	 *
+	 * Deadlock detection. If the lock is the same as the original
+	 * lock which caused us to walk the lock chain or if the
+	 * current lock is owned by the task which initiated the chain
+	 * walk, we detected a deadlock.
+	 */
+	if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
+		ret = -EDEADLK;
+
+		/*
+		 * When the deadlock is due to ww_mutex; also see above. Don't
+		 * report the deadlock and instead let the ww_mutex wound/die
+		 * logic pick which of the contending threads gets -EDEADLK.
+		 *
+		 * NOTE: assumes the cycle only contains a single ww_class; any
+		 * other configuration and we fail to report; also, see
+		 * lockdep.
+		 */
+		if (IS_ENABLED(CONFIG_PREEMPT_RT) && orig_waiter && orig_waiter->ww_ctx)
+			ret = 0;
+
+		raw_spin_unlock(&lock->wait_lock);
+		goto out_unlock_pi;
+	}
+
+	/*
+	 * If we just follow the lock chain for deadlock detection, no
+	 * need to do all the requeue operations. To avoid a truckload
+	 * of conditionals around the various places below, just do the
+	 * minimum chain walk checks.
+	 */
+	if (!requeue) {
+		/*
+		 * No requeue[7] here. Just release @task [8]
+		 */
+		raw_spin_unlock(&task->pi_lock);
+		put_task_struct(task);
+
+		/*
+		 * [9] check_exit_conditions_3 protected by lock->wait_lock.
+		 * If there is no owner of the lock, end of chain.
+		 */
+		if (!rt_mutex_owner(lock)) {
+			raw_spin_unlock_irq(&lock->wait_lock);
+			return 0;
+		}
+
+		/* [10] Grab the next task, i.e. owner of @lock */
+		task = get_task_struct(rt_mutex_owner(lock));
+		raw_spin_lock(&task->pi_lock);
+
+		/*
+		 * No requeue [11] here. We just do deadlock detection.
+		 *
+		 * [12] Store whether owner is blocked
+		 * itself. Decision is made after dropping the locks
+		 */
+		next_lock = task_blocked_on_lock(task);
+		/*
+		 * Get the top waiter for the next iteration
+		 */
+		top_waiter = rt_mutex_top_waiter(lock);
+
+		/* [13] Drop locks */
+		raw_spin_unlock(&task->pi_lock);
+		raw_spin_unlock_irq(&lock->wait_lock);
+
+		/* If owner is not blocked, end of chain. */
+		if (!next_lock)
+			goto out_put_task;
+		goto again;
+	}
+
+	/*
+	 * Store the current top waiter before doing the requeue
+	 * operation on @lock. We need it for the boost/deboost
+	 * decision below.
+	 */
+	prerequeue_top_waiter = rt_mutex_top_waiter(lock);
+
+	/* [7] Requeue the waiter in the lock waiter tree. */
+	rt_mutex_dequeue(lock, waiter);
+
+	/*
+	 * Update the waiter prio fields now that we're dequeued.
+	 *
+	 * These values can have changed through either:
+	 *
+	 *   sys_sched_set_scheduler() / sys_sched_setattr()
+	 *
+	 * or
+	 *
+	 *   DL CBS enforcement advancing the effective deadline.
+	 */
+	waiter_update_prio(waiter, task);
+
+	rt_mutex_enqueue(lock, waiter);
+
+	/*
+	 * [8] Release the (blocking) task in preparation for
+	 * taking the owner task in [10].
+	 *
+	 * Since we hold lock->waiter_lock, task cannot unblock, even if we
+	 * release task->pi_lock.
+	 */
+	raw_spin_unlock(&task->pi_lock);
+	put_task_struct(task);
+
+	/*
+	 * [9] check_exit_conditions_3 protected by lock->wait_lock.
+	 *
+	 * We must abort the chain walk if there is no lock owner even
+	 * in the dead lock detection case, as we have nothing to
+	 * follow here. This is the end of the chain we are walking.
+	 */
+	if (!rt_mutex_owner(lock)) {
+		/*
+		 * If the requeue [7] above changed the top waiter,
+		 * then we need to wake the new top waiter up to try
+		 * to get the lock.
+		 */
+		top_waiter = rt_mutex_top_waiter(lock);
+		if (prerequeue_top_waiter != top_waiter)
+			wake_up_state(top_waiter->task, top_waiter->wake_state);
+		raw_spin_unlock_irq(&lock->wait_lock);
+		return 0;
+	}
+
+	/*
+	 * [10] Grab the next task, i.e. the owner of @lock
+	 *
+	 * Per holding lock->wait_lock and checking for !owner above, there
+	 * must be an owner and it cannot go away.
+	 */
+	task = get_task_struct(rt_mutex_owner(lock));
+	raw_spin_lock(&task->pi_lock);
+
+	/* [11] requeue the pi waiters if necessary */
+	if (waiter == rt_mutex_top_waiter(lock)) {
+		/*
+		 * The waiter became the new top (highest priority)
+		 * waiter on the lock. Replace the previous top waiter
+		 * in the owner tasks pi waiters tree with this waiter
+		 * and adjust the priority of the owner.
+		 */
+		rt_mutex_dequeue_pi(task, prerequeue_top_waiter);
+		waiter_clone_prio(waiter, task);
+		rt_mutex_enqueue_pi(task, waiter);
+		rt_mutex_adjust_prio(lock, task);
+
+	} else if (prerequeue_top_waiter == waiter) {
+		/*
+		 * The waiter was the top waiter on the lock, but is
+		 * no longer the top priority waiter. Replace waiter in
+		 * the owner tasks pi waiters tree with the new top
+		 * (highest priority) waiter and adjust the priority
+		 * of the owner.
+		 * The new top waiter is stored in @waiter so that
+		 * @waiter == @top_waiter evaluates to true below and
+		 * we continue to deboost the rest of the chain.
+		 */
+		rt_mutex_dequeue_pi(task, waiter);
+		waiter = rt_mutex_top_waiter(lock);
+		waiter_clone_prio(waiter, task);
+		rt_mutex_enqueue_pi(task, waiter);
+		rt_mutex_adjust_prio(lock, task);
+	} else {
+		/*
+		 * Nothing changed. No need to do any priority
+		 * adjustment.
+		 */
+	}
+
+	/*
+	 * [12] check_exit_conditions_4() protected by task->pi_lock
+	 * and lock->wait_lock. The actual decisions are made after we
+	 * dropped the locks.
+	 *
+	 * Check whether the task which owns the current lock is pi
+	 * blocked itself. If yes we store a pointer to the lock for
+	 * the lock chain change detection above. After we dropped
+	 * task->pi_lock next_lock cannot be dereferenced anymore.
+	 */
+	next_lock = task_blocked_on_lock(task);
+	/*
+	 * Store the top waiter of @lock for the end of chain walk
+	 * decision below.
+	 */
+	top_waiter = rt_mutex_top_waiter(lock);
+
+	/* [13] Drop the locks */
+	raw_spin_unlock(&task->pi_lock);
+	raw_spin_unlock_irq(&lock->wait_lock);
+
+	/*
+	 * Make the actual exit decisions [12], based on the stored
+	 * values.
+	 *
+	 * We reached the end of the lock chain. Stop right here. No
+	 * point to go back just to figure that out.
+	 */
+	if (!next_lock)
+		goto out_put_task;
+
+	/*
+	 * If the current waiter is not the top waiter on the lock,
+	 * then we can stop the chain walk here if we are not in full
+	 * deadlock detection mode.
+	 */
+	if (!detect_deadlock && waiter != top_waiter)
+		goto out_put_task;
+
+	goto again;
+
+ out_unlock_pi:
+	raw_spin_unlock_irq(&task->pi_lock);
+ out_put_task:
+	put_task_struct(task);
+
+	return ret;
+}
+
+/*
+ * Try to take an rt-mutex
+ *
+ * Must be called with lock->wait_lock held and interrupts disabled
+ *
+ * @lock:   The lock to be acquired.
+ * @task:   The task which wants to acquire the lock
+ * @waiter: The waiter that is queued to the lock's wait tree if the
+ *	    callsite called task_blocked_on_lock(), otherwise NULL
+ */
+static int __sched
+try_to_take_rt_mutex(struct rt_mutex_base *lock, struct task_struct *task,
+		     struct rt_mutex_waiter *waiter)
+{
+	lockdep_assert_held(&lock->wait_lock);
+
+	/*
+	 * Before testing whether we can acquire @lock, we set the
+	 * RT_MUTEX_HAS_WAITERS bit in @lock->owner. This forces all
+	 * other tasks which try to modify @lock into the slow path
+	 * and they serialize on @lock->wait_lock.
+	 *
+	 * The RT_MUTEX_HAS_WAITERS bit can have a transitional state
+	 * as explained at the top of this file if and only if:
+	 *
+	 * - There is a lock owner. The caller must fixup the
+	 *   transient state if it does a trylock or leaves the lock
+	 *   function due to a signal or timeout.
+	 *
+	 * - @task acquires the lock and there are no other
+	 *   waiters. This is undone in rt_mutex_set_owner(@task) at
+	 *   the end of this function.
+	 */
+	mark_rt_mutex_waiters(lock);
+
+	/*
+	 * If @lock has an owner, give up.
+	 */
+	if (rt_mutex_owner(lock))
+		return 0;
+
+	/*
+	 * If @waiter != NULL, @task has already enqueued the waiter
+	 * into @lock waiter tree. If @waiter == NULL then this is a
+	 * trylock attempt.
+	 */
+	if (waiter) {
+		struct rt_mutex_waiter *top_waiter = rt_mutex_top_waiter(lock);
+
+		/*
+		 * If waiter is the highest priority waiter of @lock,
+		 * or allowed to steal it, take it over.
+		 */
+		if (waiter == top_waiter || rt_mutex_steal(waiter, top_waiter)) {
+			/*
+			 * We can acquire the lock. Remove the waiter from the
+			 * lock waiters tree.
+			 */
+			rt_mutex_dequeue(lock, waiter);
+		} else {
+			return 0;
+		}
+	} else {
+		/*
+		 * If the lock has waiters already we check whether @task is
+		 * eligible to take over the lock.
+		 *
+		 * If there are no other waiters, @task can acquire
+		 * the lock.  @task->pi_blocked_on is NULL, so it does
+		 * not need to be dequeued.
+		 */
+		if (rt_mutex_has_waiters(lock)) {
+			/* Check whether the trylock can steal it. */
+			if (!rt_mutex_steal(task_to_waiter(task),
+					    rt_mutex_top_waiter(lock)))
+				return 0;
+
+			/*
+			 * The current top waiter stays enqueued. We
+			 * don't have to change anything in the lock
+			 * waiters order.
+			 */
+		} else {
+			/*
+			 * No waiters. Take the lock without the
+			 * pi_lock dance.@task->pi_blocked_on is NULL
+			 * and we have no waiters to enqueue in @task
+			 * pi waiters tree.
+			 */
+			goto takeit;
+		}
+	}
+
+	/*
+	 * Clear @task->pi_blocked_on. Requires protection by
+	 * @task->pi_lock. Redundant operation for the @waiter == NULL
+	 * case, but conditionals are more expensive than a redundant
+	 * store.
+	 */
+	raw_spin_lock(&task->pi_lock);
+	task->pi_blocked_on = NULL;
+	/*
+	 * Finish the lock acquisition. @task is the new owner. If
+	 * other waiters exist we have to insert the highest priority
+	 * waiter into @task->pi_waiters tree.
+	 */
+	if (rt_mutex_has_waiters(lock))
+		rt_mutex_enqueue_pi(task, rt_mutex_top_waiter(lock));
+	raw_spin_unlock(&task->pi_lock);
+
+takeit:
+	/*
+	 * This either preserves the RT_MUTEX_HAS_WAITERS bit if there
+	 * are still waiters or clears it.
+	 */
+	rt_mutex_set_owner(lock, task);
+
+	return 1;
+}
+
+/*
+ * Task blocks on lock.
+ *
+ * Prepare waiter and propagate pi chain
+ *
+ * This must be called with lock->wait_lock held and interrupts disabled
+ */
+static int __sched task_blocks_on_rt_mutex(struct rt_mutex_base *lock,
+					   struct rt_mutex_waiter *waiter,
+					   struct task_struct *task,
+					   struct ww_acquire_ctx *ww_ctx,
+					   enum rtmutex_chainwalk chwalk)
+{
+	struct task_struct *owner = rt_mutex_owner(lock);
+	struct rt_mutex_waiter *top_waiter = waiter;
+	struct rt_mutex_base *next_lock;
+	int chain_walk = 0, res;
+
+	lockdep_assert_held(&lock->wait_lock);
+
+	/*
+	 * Early deadlock detection. We really don't want the task to
+	 * enqueue on itself just to untangle the mess later. It's not
+	 * only an optimization. We drop the locks, so another waiter
+	 * can come in before the chain walk detects the deadlock. So
+	 * the other will detect the deadlock and return -EDEADLOCK,
+	 * which is wrong, as the other waiter is not in a deadlock
+	 * situation.
+	 *
+	 * Except for ww_mutex, in that case the chain walk must already deal
+	 * with spurious cycles, see the comments at [3] and [6].
+	 */
+	if (owner == task && !(build_ww_mutex() && ww_ctx))
+		return -EDEADLK;
+
+	raw_spin_lock(&task->pi_lock);
+	waiter->task = task;
+	waiter->lock = lock;
+	waiter_update_prio(waiter, task);
+	waiter_clone_prio(waiter, task);
+
+	/* Get the top priority waiter on the lock */
+	if (rt_mutex_has_waiters(lock))
+		top_waiter = rt_mutex_top_waiter(lock);
+	rt_mutex_enqueue(lock, waiter);
+
+	task->pi_blocked_on = waiter;
+
+	raw_spin_unlock(&task->pi_lock);
+
+	if (build_ww_mutex() && ww_ctx) {
+		struct rt_mutex *rtm;
+
+		/* Check whether the waiter should back out immediately */
+		rtm = container_of(lock, struct rt_mutex, rtmutex);
+		res = __ww_mutex_add_waiter(waiter, rtm, ww_ctx);
+		if (res) {
+			raw_spin_lock(&task->pi_lock);
+			rt_mutex_dequeue(lock, waiter);
+			task->pi_blocked_on = NULL;
+			raw_spin_unlock(&task->pi_lock);
+			return res;
+		}
+	}
+
+	if (!owner)
+		return 0;
+
+	raw_spin_lock(&owner->pi_lock);
+	if (waiter == rt_mutex_top_waiter(lock)) {
+		rt_mutex_dequeue_pi(owner, top_waiter);
+		rt_mutex_enqueue_pi(owner, waiter);
+
+		rt_mutex_adjust_prio(lock, owner);
+		if (owner->pi_blocked_on)
+			chain_walk = 1;
+	} else if (rt_mutex_cond_detect_deadlock(waiter, chwalk)) {
+		chain_walk = 1;
+	}
+
+	/* Store the lock on which owner is blocked or NULL */
+	next_lock = task_blocked_on_lock(owner);
+
+	raw_spin_unlock(&owner->pi_lock);
+	/*
+	 * Even if full deadlock detection is on, if the owner is not
+	 * blocked itself, we can avoid finding this out in the chain
+	 * walk.
+	 */
+	if (!chain_walk || !next_lock)
+		return 0;
+
+	/*
+	 * The owner can't disappear while holding a lock,
+	 * so the owner struct is protected by wait_lock.
+	 * Gets dropped in rt_mutex_adjust_prio_chain()!
+	 */
+	get_task_struct(owner);
+
+	raw_spin_unlock_irq(&lock->wait_lock);
+
+	res = rt_mutex_adjust_prio_chain(owner, chwalk, lock,
+					 next_lock, waiter, task);
+
+	raw_spin_lock_irq(&lock->wait_lock);
+
+	return res;
+}
+
+/*
+ * Remove the top waiter from the current tasks pi waiter tree and
+ * queue it up.
+ *
+ * Called with lock->wait_lock held and interrupts disabled.
+ */
+static void __sched mark_wakeup_next_waiter(struct rt_wake_q_head *wqh,
+					    struct rt_mutex_base *lock)
+{
+	struct rt_mutex_waiter *waiter;
+
+	lockdep_assert_held(&lock->wait_lock);
+
+	raw_spin_lock(&current->pi_lock);
+
+	waiter = rt_mutex_top_waiter(lock);
+
+	/*
+	 * Remove it from current->pi_waiters and deboost.
+	 *
+	 * We must in fact deboost here in order to ensure we call
+	 * rt_mutex_setprio() to update p->pi_top_task before the
+	 * task unblocks.
+	 */
+	rt_mutex_dequeue_pi(current, waiter);
+	rt_mutex_adjust_prio(lock, current);
+
+	/*
+	 * As we are waking up the top waiter, and the waiter stays
+	 * queued on the lock until it gets the lock, this lock
+	 * obviously has waiters. Just set the bit here and this has
+	 * the added benefit of forcing all new tasks into the
+	 * slow path making sure no task of lower priority than
+	 * the top waiter can steal this lock.
+	 */
+	lock->owner = (void *) RT_MUTEX_HAS_WAITERS;
+
+	/*
+	 * We deboosted before waking the top waiter task such that we don't
+	 * run two tasks with the 'same' priority (and ensure the
+	 * p->pi_top_task pointer points to a blocked task). This however can
+	 * lead to priority inversion if we would get preempted after the
+	 * deboost but before waking our donor task, hence the preempt_disable()
+	 * before unlock.
+	 *
+	 * Pairs with preempt_enable() in rt_mutex_wake_up_q();
+	 */
+	preempt_disable();
+	rt_mutex_wake_q_add(wqh, waiter);
+	raw_spin_unlock(&current->pi_lock);
+}
+
+static int __sched __rt_mutex_slowtrylock(struct rt_mutex_base *lock)
+{
+	int ret = try_to_take_rt_mutex(lock, current, NULL);
+
+	/*
+	 * try_to_take_rt_mutex() sets the lock waiters bit
+	 * unconditionally. Clean this up.
+	 */
+	fixup_rt_mutex_waiters(lock, true);
+
+	return ret;
+}
+
+/*
+ * Slow path try-lock function:
+ */
+static int __sched rt_mutex_slowtrylock(struct rt_mutex_base *lock)
+{
+	unsigned long flags;
+	int ret;
+
+	/*
+	 * If the lock already has an owner we fail to get the lock.
+	 * This can be done without taking the @lock->wait_lock as
+	 * it is only being read, and this is a trylock anyway.
+	 */
+	if (rt_mutex_owner(lock))
+		return 0;
+
+	/*
+	 * The mutex has currently no owner. Lock the wait lock and try to
+	 * acquire the lock. We use irqsave here to support early boot calls.
+	 */
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+
+	ret = __rt_mutex_slowtrylock(lock);
+
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+
+	return ret;
+}
+
+static __always_inline int __rt_mutex_trylock(struct rt_mutex_base *lock)
+{
+	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
+		return 1;
+
+	return rt_mutex_slowtrylock(lock);
+}
+
+/*
+ * Slow path to release a rt-mutex.
+ */
+static void __sched rt_mutex_slowunlock(struct rt_mutex_base *lock)
+{
+	DEFINE_RT_WAKE_Q(wqh);
+	unsigned long flags;
+
+	/* irqsave required to support early boot calls */
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+
+	debug_rt_mutex_unlock(lock);
+
+	/*
+	 * We must be careful here if the fast path is enabled. If we
+	 * have no waiters queued we cannot set owner to NULL here
+	 * because of:
+	 *
+	 * foo->lock->owner = NULL;
+	 *			rtmutex_lock(foo->lock);   <- fast path
+	 *			free = atomic_dec_and_test(foo->refcnt);
+	 *			rtmutex_unlock(foo->lock); <- fast path
+	 *			if (free)
+	 *				kfree(foo);
+	 * raw_spin_unlock(foo->lock->wait_lock);
+	 *
+	 * So for the fastpath enabled kernel:
+	 *
+	 * Nothing can set the waiters bit as long as we hold
+	 * lock->wait_lock. So we do the following sequence:
+	 *
+	 *	owner = rt_mutex_owner(lock);
+	 *	clear_rt_mutex_waiters(lock);
+	 *	raw_spin_unlock(&lock->wait_lock);
+	 *	if (cmpxchg(&lock->owner, owner, 0) == owner)
+	 *		return;
+	 *	goto retry;
+	 *
+	 * The fastpath disabled variant is simple as all access to
+	 * lock->owner is serialized by lock->wait_lock:
+	 *
+	 *	lock->owner = NULL;
+	 *	raw_spin_unlock(&lock->wait_lock);
+	 */
+	while (!rt_mutex_has_waiters(lock)) {
+		/* Drops lock->wait_lock ! */
+		if (unlock_rt_mutex_safe(lock, flags) == true)
+			return;
+		/* Relock the rtmutex and try again */
+		raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	}
+
+	/*
+	 * The wakeup next waiter path does not suffer from the above
+	 * race. See the comments there.
+	 *
+	 * Queue the next waiter for wakeup once we release the wait_lock.
+	 */
+	mark_wakeup_next_waiter(&wqh, lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+
+	rt_mutex_wake_up_q(&wqh);
+}
+
+static __always_inline void __rt_mutex_unlock(struct rt_mutex_base *lock)
+{
+	if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
+		return;
+
+	rt_mutex_slowunlock(lock);
+}
+
+#ifdef CONFIG_SMP
+static bool rtmutex_spin_on_owner(struct rt_mutex_base *lock,
+				  struct rt_mutex_waiter *waiter,
+				  struct task_struct *owner)
+{
+	bool res = true;
+
+	rcu_read_lock();
+	for (;;) {
+		/* If owner changed, trylock again. */
+		if (owner != rt_mutex_owner(lock))
+			break;
+		/*
+		 * Ensure that @owner is dereferenced after checking that
+		 * the lock owner still matches @owner. If that fails,
+		 * @owner might point to freed memory. If it still matches,
+		 * the rcu_read_lock() ensures the memory stays valid.
+		 */
+		barrier();
+		/*
+		 * Stop spinning when:
+		 *  - the lock owner has been scheduled out
+		 *  - current is not longer the top waiter
+		 *  - current is requested to reschedule (redundant
+		 *    for CONFIG_PREEMPT_RCU=y)
+		 *  - the VCPU on which owner runs is preempted
+		 */
+		if (!owner_on_cpu(owner) || need_resched() ||
+		    !rt_mutex_waiter_is_top_waiter(lock, waiter)) {
+			res = false;
+			break;
+		}
+		cpu_relax();
+	}
+	rcu_read_unlock();
+	return res;
+}
+#else
+static bool rtmutex_spin_on_owner(struct rt_mutex_base *lock,
+				  struct rt_mutex_waiter *waiter,
+				  struct task_struct *owner)
+{
+	return false;
+}
+#endif
+
+#ifdef RT_MUTEX_BUILD_MUTEX
+/*
+ * Functions required for:
+ *	- rtmutex, futex on all kernels
+ *	- mutex and rwsem substitutions on RT kernels
+ */
+
+/*
+ * Remove a waiter from a lock and give up
+ *
+ * Must be called with lock->wait_lock held and interrupts disabled. It must
+ * have just failed to try_to_take_rt_mutex().
+ */
+static void __sched remove_waiter(struct rt_mutex_base *lock,
+				  struct rt_mutex_waiter *waiter)
+{
+	bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock));
+	struct task_struct *owner = rt_mutex_owner(lock);
+	struct rt_mutex_base *next_lock;
+
+	lockdep_assert_held(&lock->wait_lock);
+
+	raw_spin_lock(&current->pi_lock);
+	rt_mutex_dequeue(lock, waiter);
+	current->pi_blocked_on = NULL;
+	raw_spin_unlock(&current->pi_lock);
+
+	/*
+	 * Only update priority if the waiter was the highest priority
+	 * waiter of the lock and there is an owner to update.
+	 */
+	if (!owner || !is_top_waiter)
+		return;
+
+	raw_spin_lock(&owner->pi_lock);
+
+	rt_mutex_dequeue_pi(owner, waiter);
+
+	if (rt_mutex_has_waiters(lock))
+		rt_mutex_enqueue_pi(owner, rt_mutex_top_waiter(lock));
+
+	rt_mutex_adjust_prio(lock, owner);
+
+	/* Store the lock on which owner is blocked or NULL */
+	next_lock = task_blocked_on_lock(owner);
+
+	raw_spin_unlock(&owner->pi_lock);
+
+	/*
+	 * Don't walk the chain, if the owner task is not blocked
+	 * itself.
+	 */
+	if (!next_lock)
+		return;
+
+	/* gets dropped in rt_mutex_adjust_prio_chain()! */
+	get_task_struct(owner);
+
+	raw_spin_unlock_irq(&lock->wait_lock);
+
+	rt_mutex_adjust_prio_chain(owner, RT_MUTEX_MIN_CHAINWALK, lock,
+				   next_lock, NULL, current);
+
+	raw_spin_lock_irq(&lock->wait_lock);
+}
+
+/**
+ * rt_mutex_slowlock_block() - Perform the wait-wake-try-to-take loop
+ * @lock:		 the rt_mutex to take
+ * @ww_ctx:		 WW mutex context pointer
+ * @state:		 the state the task should block in (TASK_INTERRUPTIBLE
+ *			 or TASK_UNINTERRUPTIBLE)
+ * @timeout:		 the pre-initialized and started timer, or NULL for none
+ * @waiter:		 the pre-initialized rt_mutex_waiter
+ *
+ * Must be called with lock->wait_lock held and interrupts disabled
+ */
+static int __sched rt_mutex_slowlock_block(struct rt_mutex_base *lock,
+					   struct ww_acquire_ctx *ww_ctx,
+					   unsigned int state,
+					   struct hrtimer_sleeper *timeout,
+					   struct rt_mutex_waiter *waiter)
+{
+	struct rt_mutex *rtm = container_of(lock, struct rt_mutex, rtmutex);
+	struct task_struct *owner;
+	int ret = 0;
+
+	for (;;) {
+		/* Try to acquire the lock: */
+		if (try_to_take_rt_mutex(lock, current, waiter))
+			break;
+
+		if (timeout && !timeout->task) {
+			ret = -ETIMEDOUT;
+			break;
+		}
+		if (signal_pending_state(state, current)) {
+			ret = -EINTR;
+			break;
+		}
+
+		if (build_ww_mutex() && ww_ctx) {
+			ret = __ww_mutex_check_kill(rtm, waiter, ww_ctx);
+			if (ret)
+				break;
+		}
+
+		if (waiter == rt_mutex_top_waiter(lock))
+			owner = rt_mutex_owner(lock);
+		else
+			owner = NULL;
+		raw_spin_unlock_irq(&lock->wait_lock);
+
+		if (!owner || !rtmutex_spin_on_owner(lock, waiter, owner))
+			schedule();
+
+		raw_spin_lock_irq(&lock->wait_lock);
+		set_current_state(state);
+	}
+
+	__set_current_state(TASK_RUNNING);
+	return ret;
+}
+
+static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock,
+					     struct rt_mutex_waiter *w)
+{
+	/*
+	 * If the result is not -EDEADLOCK or the caller requested
+	 * deadlock detection, nothing to do here.
+	 */
+	if (res != -EDEADLOCK || detect_deadlock)
+		return;
+
+	if (build_ww_mutex() && w->ww_ctx)
+		return;
+
+	/*
+	 * Yell loudly and stop the task right here.
+	 */
+	WARN(1, "rtmutex deadlock detected\n");
+	while (1) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule();
+	}
+}
+
+/**
+ * __rt_mutex_slowlock - Locking slowpath invoked with lock::wait_lock held
+ * @lock:	The rtmutex to block lock
+ * @ww_ctx:	WW mutex context pointer
+ * @state:	The task state for sleeping
+ * @chwalk:	Indicator whether full or partial chainwalk is requested
+ * @waiter:	Initializer waiter for blocking
+ */
+static int __sched __rt_mutex_slowlock(struct rt_mutex_base *lock,
+				       struct ww_acquire_ctx *ww_ctx,
+				       unsigned int state,
+				       enum rtmutex_chainwalk chwalk,
+				       struct rt_mutex_waiter *waiter)
+{
+	struct rt_mutex *rtm = container_of(lock, struct rt_mutex, rtmutex);
+	struct ww_mutex *ww = ww_container_of(rtm);
+	int ret;
+
+	lockdep_assert_held(&lock->wait_lock);
+
+	/* Try to acquire the lock again: */
+	if (try_to_take_rt_mutex(lock, current, NULL)) {
+		if (build_ww_mutex() && ww_ctx) {
+			__ww_mutex_check_waiters(rtm, ww_ctx);
+			ww_mutex_lock_acquired(ww, ww_ctx);
+		}
+		return 0;
+	}
+
+	set_current_state(state);
+
+	trace_contention_begin(lock, LCB_F_RT);
+
+	ret = task_blocks_on_rt_mutex(lock, waiter, current, ww_ctx, chwalk);
+	if (likely(!ret))
+		ret = rt_mutex_slowlock_block(lock, ww_ctx, state, NULL, waiter);
+
+	if (likely(!ret)) {
+		/* acquired the lock */
+		if (build_ww_mutex() && ww_ctx) {
+			if (!ww_ctx->is_wait_die)
+				__ww_mutex_check_waiters(rtm, ww_ctx);
+			ww_mutex_lock_acquired(ww, ww_ctx);
+		}
+	} else {
+		__set_current_state(TASK_RUNNING);
+		remove_waiter(lock, waiter);
+		rt_mutex_handle_deadlock(ret, chwalk, waiter);
+	}
+
+	/*
+	 * try_to_take_rt_mutex() sets the waiter bit
+	 * unconditionally. We might have to fix that up.
+	 */
+	fixup_rt_mutex_waiters(lock, true);
+
+	trace_contention_end(lock, ret);
+
+	return ret;
+}
+
+static inline int __rt_mutex_slowlock_locked(struct rt_mutex_base *lock,
+					     struct ww_acquire_ctx *ww_ctx,
+					     unsigned int state)
+{
+	struct rt_mutex_waiter waiter;
+	int ret;
+
+	rt_mutex_init_waiter(&waiter);
+	waiter.ww_ctx = ww_ctx;
+
+	ret = __rt_mutex_slowlock(lock, ww_ctx, state, RT_MUTEX_MIN_CHAINWALK,
+				  &waiter);
+
+	debug_rt_mutex_free_waiter(&waiter);
+	return ret;
+}
+
+/*
+ * rt_mutex_slowlock - Locking slowpath invoked when fast path fails
+ * @lock:	The rtmutex to block lock
+ * @ww_ctx:	WW mutex context pointer
+ * @state:	The task state for sleeping
+ */
+static int __sched rt_mutex_slowlock(struct rt_mutex_base *lock,
+				     struct ww_acquire_ctx *ww_ctx,
+				     unsigned int state)
+{
+	unsigned long flags;
+	int ret;
+
+	/*
+	 * Technically we could use raw_spin_[un]lock_irq() here, but this can
+	 * be called in early boot if the cmpxchg() fast path is disabled
+	 * (debug, no architecture support). In this case we will acquire the
+	 * rtmutex with lock->wait_lock held. But we cannot unconditionally
+	 * enable interrupts in that early boot case. So we need to use the
+	 * irqsave/restore variants.
+	 */
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	ret = __rt_mutex_slowlock_locked(lock, ww_ctx, state);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+
+	return ret;
+}
+
+static __always_inline int __rt_mutex_lock(struct rt_mutex_base *lock,
+					   unsigned int state)
+{
+	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
+		return 0;
+
+	return rt_mutex_slowlock(lock, NULL, state);
+}
+#endif /* RT_MUTEX_BUILD_MUTEX */
+
+#ifdef RT_MUTEX_BUILD_SPINLOCKS
+/*
+ * Functions required for spin/rw_lock substitution on RT kernels
+ */
+
+/**
+ * rtlock_slowlock_locked - Slow path lock acquisition for RT locks
+ * @lock:	The underlying RT mutex
+ */
+static void __sched rtlock_slowlock_locked(struct rt_mutex_base *lock)
+{
+	struct rt_mutex_waiter waiter;
+	struct task_struct *owner;
+
+	lockdep_assert_held(&lock->wait_lock);
+
+	if (try_to_take_rt_mutex(lock, current, NULL))
+		return;
+
+	rt_mutex_init_rtlock_waiter(&waiter);
+
+	/* Save current state and set state to TASK_RTLOCK_WAIT */
+	current_save_and_set_rtlock_wait_state();
+
+	trace_contention_begin(lock, LCB_F_RT);
+
+	task_blocks_on_rt_mutex(lock, &waiter, current, NULL, RT_MUTEX_MIN_CHAINWALK);
+
+	for (;;) {
+		/* Try to acquire the lock again */
+		if (try_to_take_rt_mutex(lock, current, &waiter))
+			break;
+
+		if (&waiter == rt_mutex_top_waiter(lock))
+			owner = rt_mutex_owner(lock);
+		else
+			owner = NULL;
+		raw_spin_unlock_irq(&lock->wait_lock);
+
+		if (!owner || !rtmutex_spin_on_owner(lock, &waiter, owner))
+			schedule_rtlock();
+
+		raw_spin_lock_irq(&lock->wait_lock);
+		set_current_state(TASK_RTLOCK_WAIT);
+	}
+
+	/* Restore the task state */
+	current_restore_rtlock_saved_state();
+
+	/*
+	 * try_to_take_rt_mutex() sets the waiter bit unconditionally.
+	 * We might have to fix that up:
+	 */
+	fixup_rt_mutex_waiters(lock, true);
+	debug_rt_mutex_free_waiter(&waiter);
+
+	trace_contention_end(lock, 0);
+}
+
+static __always_inline void __sched rtlock_slowlock(struct rt_mutex_base *lock)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	rtlock_slowlock_locked(lock);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+}
+
+#endif /* RT_MUTEX_BUILD_SPINLOCKS */
diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c
new file mode 100644
index 000000000..a6974d044
--- /dev/null
+++ b/kernel/locking/rtmutex_api.c
@@ -0,0 +1,612 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * rtmutex API
+ */
+#include <linux/spinlock.h>
+#include <linux/export.h>
+
+#define RT_MUTEX_BUILD_MUTEX
+#include "rtmutex.c"
+
+/*
+ * Max number of times we'll walk the boosting chain:
+ */
+int max_lock_depth = 1024;
+
+/*
+ * Debug aware fast / slowpath lock,trylock,unlock
+ *
+ * The atomic acquire/release ops are compiled away, when either the
+ * architecture does not support cmpxchg or when debugging is enabled.
+ */
+static __always_inline int __rt_mutex_lock_common(struct rt_mutex *lock,
+						  unsigned int state,
+						  struct lockdep_map *nest_lock,
+						  unsigned int subclass)
+{
+	int ret;
+
+	might_sleep();
+	mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, _RET_IP_);
+	ret = __rt_mutex_lock(&lock->rtmutex, state);
+	if (ret)
+		mutex_release(&lock->dep_map, _RET_IP_);
+	return ret;
+}
+
+void rt_mutex_base_init(struct rt_mutex_base *rtb)
+{
+	__rt_mutex_base_init(rtb);
+}
+EXPORT_SYMBOL(rt_mutex_base_init);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+/**
+ * rt_mutex_lock_nested - lock a rt_mutex
+ *
+ * @lock: the rt_mutex to be locked
+ * @subclass: the lockdep subclass
+ */
+void __sched rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass)
+{
+	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, NULL, subclass);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock_nested);
+
+void __sched _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *nest_lock)
+{
+	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, nest_lock, 0);
+}
+EXPORT_SYMBOL_GPL(_rt_mutex_lock_nest_lock);
+
+#else /* !CONFIG_DEBUG_LOCK_ALLOC */
+
+/**
+ * rt_mutex_lock - lock a rt_mutex
+ *
+ * @lock: the rt_mutex to be locked
+ */
+void __sched rt_mutex_lock(struct rt_mutex *lock)
+{
+	__rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, NULL, 0);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock);
+#endif
+
+/**
+ * rt_mutex_lock_interruptible - lock a rt_mutex interruptible
+ *
+ * @lock:		the rt_mutex to be locked
+ *
+ * Returns:
+ *  0		on success
+ * -EINTR	when interrupted by a signal
+ */
+int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock)
+{
+	return __rt_mutex_lock_common(lock, TASK_INTERRUPTIBLE, NULL, 0);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
+
+/**
+ * rt_mutex_lock_killable - lock a rt_mutex killable
+ *
+ * @lock:		the rt_mutex to be locked
+ *
+ * Returns:
+ *  0		on success
+ * -EINTR	when interrupted by a signal
+ */
+int __sched rt_mutex_lock_killable(struct rt_mutex *lock)
+{
+	return __rt_mutex_lock_common(lock, TASK_KILLABLE, NULL, 0);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock_killable);
+
+/**
+ * rt_mutex_trylock - try to lock a rt_mutex
+ *
+ * @lock:	the rt_mutex to be locked
+ *
+ * This function can only be called in thread context. It's safe to call it
+ * from atomic regions, but not from hard or soft interrupt context.
+ *
+ * Returns:
+ *  1 on success
+ *  0 on contention
+ */
+int __sched rt_mutex_trylock(struct rt_mutex *lock)
+{
+	int ret;
+
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task()))
+		return 0;
+
+	ret = __rt_mutex_trylock(&lock->rtmutex);
+	if (ret)
+		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rt_mutex_trylock);
+
+/**
+ * rt_mutex_unlock - unlock a rt_mutex
+ *
+ * @lock: the rt_mutex to be unlocked
+ */
+void __sched rt_mutex_unlock(struct rt_mutex *lock)
+{
+	mutex_release(&lock->dep_map, _RET_IP_);
+	__rt_mutex_unlock(&lock->rtmutex);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_unlock);
+
+/*
+ * Futex variants, must not use fastpath.
+ */
+int __sched rt_mutex_futex_trylock(struct rt_mutex_base *lock)
+{
+	return rt_mutex_slowtrylock(lock);
+}
+
+int __sched __rt_mutex_futex_trylock(struct rt_mutex_base *lock)
+{
+	return __rt_mutex_slowtrylock(lock);
+}
+
+/**
+ * __rt_mutex_futex_unlock - Futex variant, that since futex variants
+ * do not use the fast-path, can be simple and will not need to retry.
+ *
+ * @lock:	The rt_mutex to be unlocked
+ * @wqh:	The wake queue head from which to get the next lock waiter
+ */
+bool __sched __rt_mutex_futex_unlock(struct rt_mutex_base *lock,
+				     struct rt_wake_q_head *wqh)
+{
+	lockdep_assert_held(&lock->wait_lock);
+
+	debug_rt_mutex_unlock(lock);
+
+	if (!rt_mutex_has_waiters(lock)) {
+		lock->owner = NULL;
+		return false; /* done */
+	}
+
+	/*
+	 * We've already deboosted, mark_wakeup_next_waiter() will
+	 * retain preempt_disabled when we drop the wait_lock, to
+	 * avoid inversion prior to the wakeup.  preempt_disable()
+	 * therein pairs with rt_mutex_postunlock().
+	 */
+	mark_wakeup_next_waiter(wqh, lock);
+
+	return true; /* call postunlock() */
+}
+
+void __sched rt_mutex_futex_unlock(struct rt_mutex_base *lock)
+{
+	DEFINE_RT_WAKE_Q(wqh);
+	unsigned long flags;
+	bool postunlock;
+
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	postunlock = __rt_mutex_futex_unlock(lock, &wqh);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+
+	if (postunlock)
+		rt_mutex_postunlock(&wqh);
+}
+
+/**
+ * __rt_mutex_init - initialize the rt_mutex
+ *
+ * @lock:	The rt_mutex to be initialized
+ * @name:	The lock name used for debugging
+ * @key:	The lock class key used for debugging
+ *
+ * Initialize the rt_mutex to unlocked state.
+ *
+ * Initializing of a locked rt_mutex is not allowed
+ */
+void __sched __rt_mutex_init(struct rt_mutex *lock, const char *name,
+			     struct lock_class_key *key)
+{
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	__rt_mutex_base_init(&lock->rtmutex);
+	lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_SLEEP);
+}
+EXPORT_SYMBOL_GPL(__rt_mutex_init);
+
+/**
+ * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
+ *				proxy owner
+ *
+ * @lock:	the rt_mutex to be locked
+ * @proxy_owner:the task to set as owner
+ *
+ * No locking. Caller has to do serializing itself
+ *
+ * Special API call for PI-futex support. This initializes the rtmutex and
+ * assigns it to @proxy_owner. Concurrent operations on the rtmutex are not
+ * possible at this point because the pi_state which contains the rtmutex
+ * is not yet visible to other tasks.
+ */
+void __sched rt_mutex_init_proxy_locked(struct rt_mutex_base *lock,
+					struct task_struct *proxy_owner)
+{
+	static struct lock_class_key pi_futex_key;
+
+	__rt_mutex_base_init(lock);
+	/*
+	 * On PREEMPT_RT the futex hashbucket spinlock becomes 'sleeping'
+	 * and rtmutex based. That causes a lockdep false positive, because
+	 * some of the futex functions invoke spin_unlock(&hb->lock) with
+	 * the wait_lock of the rtmutex associated to the pi_futex held.
+	 * spin_unlock() in turn takes wait_lock of the rtmutex on which
+	 * the spinlock is based, which makes lockdep notice a lock
+	 * recursion. Give the futex/rtmutex wait_lock a separate key.
+	 */
+	lockdep_set_class(&lock->wait_lock, &pi_futex_key);
+	rt_mutex_set_owner(lock, proxy_owner);
+}
+
+/**
+ * rt_mutex_proxy_unlock - release a lock on behalf of owner
+ *
+ * @lock:	the rt_mutex to be locked
+ *
+ * No locking. Caller has to do serializing itself
+ *
+ * Special API call for PI-futex support. This just cleans up the rtmutex
+ * (debugging) state. Concurrent operations on this rt_mutex are not
+ * possible because it belongs to the pi_state which is about to be freed
+ * and it is not longer visible to other tasks.
+ */
+void __sched rt_mutex_proxy_unlock(struct rt_mutex_base *lock)
+{
+	debug_rt_mutex_proxy_unlock(lock);
+	rt_mutex_clear_owner(lock);
+}
+
+/**
+ * __rt_mutex_start_proxy_lock() - Start lock acquisition for another task
+ * @lock:		the rt_mutex to take
+ * @waiter:		the pre-initialized rt_mutex_waiter
+ * @task:		the task to prepare
+ *
+ * Starts the rt_mutex acquire; it enqueues the @waiter and does deadlock
+ * detection. It does not wait, see rt_mutex_wait_proxy_lock() for that.
+ *
+ * NOTE: does _NOT_ remove the @waiter on failure; must either call
+ * rt_mutex_wait_proxy_lock() or rt_mutex_cleanup_proxy_lock() after this.
+ *
+ * Returns:
+ *  0 - task blocked on lock
+ *  1 - acquired the lock for task, caller should wake it up
+ * <0 - error
+ *
+ * Special API call for PI-futex support.
+ */
+int __sched __rt_mutex_start_proxy_lock(struct rt_mutex_base *lock,
+					struct rt_mutex_waiter *waiter,
+					struct task_struct *task)
+{
+	int ret;
+
+	lockdep_assert_held(&lock->wait_lock);
+
+	if (try_to_take_rt_mutex(lock, task, NULL))
+		return 1;
+
+	/* We enforce deadlock detection for futexes */
+	ret = task_blocks_on_rt_mutex(lock, waiter, task, NULL,
+				      RT_MUTEX_FULL_CHAINWALK);
+
+	if (ret && !rt_mutex_owner(lock)) {
+		/*
+		 * Reset the return value. We might have
+		 * returned with -EDEADLK and the owner
+		 * released the lock while we were walking the
+		 * pi chain.  Let the waiter sort it out.
+		 */
+		ret = 0;
+	}
+
+	return ret;
+}
+
+/**
+ * rt_mutex_start_proxy_lock() - Start lock acquisition for another task
+ * @lock:		the rt_mutex to take
+ * @waiter:		the pre-initialized rt_mutex_waiter
+ * @task:		the task to prepare
+ *
+ * Starts the rt_mutex acquire; it enqueues the @waiter and does deadlock
+ * detection. It does not wait, see rt_mutex_wait_proxy_lock() for that.
+ *
+ * NOTE: unlike __rt_mutex_start_proxy_lock this _DOES_ remove the @waiter
+ * on failure.
+ *
+ * Returns:
+ *  0 - task blocked on lock
+ *  1 - acquired the lock for task, caller should wake it up
+ * <0 - error
+ *
+ * Special API call for PI-futex support.
+ */
+int __sched rt_mutex_start_proxy_lock(struct rt_mutex_base *lock,
+				      struct rt_mutex_waiter *waiter,
+				      struct task_struct *task)
+{
+	int ret;
+
+	raw_spin_lock_irq(&lock->wait_lock);
+	ret = __rt_mutex_start_proxy_lock(lock, waiter, task);
+	if (unlikely(ret))
+		remove_waiter(lock, waiter);
+	raw_spin_unlock_irq(&lock->wait_lock);
+
+	return ret;
+}
+
+/**
+ * rt_mutex_wait_proxy_lock() - Wait for lock acquisition
+ * @lock:		the rt_mutex we were woken on
+ * @to:			the timeout, null if none. hrtimer should already have
+ *			been started.
+ * @waiter:		the pre-initialized rt_mutex_waiter
+ *
+ * Wait for the lock acquisition started on our behalf by
+ * rt_mutex_start_proxy_lock(). Upon failure, the caller must call
+ * rt_mutex_cleanup_proxy_lock().
+ *
+ * Returns:
+ *  0 - success
+ * <0 - error, one of -EINTR, -ETIMEDOUT
+ *
+ * Special API call for PI-futex support
+ */
+int __sched rt_mutex_wait_proxy_lock(struct rt_mutex_base *lock,
+				     struct hrtimer_sleeper *to,
+				     struct rt_mutex_waiter *waiter)
+{
+	int ret;
+
+	raw_spin_lock_irq(&lock->wait_lock);
+	/* sleep on the mutex */
+	set_current_state(TASK_INTERRUPTIBLE);
+	ret = rt_mutex_slowlock_block(lock, NULL, TASK_INTERRUPTIBLE, to, waiter);
+	/*
+	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
+	 * have to fix that up.
+	 */
+	fixup_rt_mutex_waiters(lock, true);
+	raw_spin_unlock_irq(&lock->wait_lock);
+
+	return ret;
+}
+
+/**
+ * rt_mutex_cleanup_proxy_lock() - Cleanup failed lock acquisition
+ * @lock:		the rt_mutex we were woken on
+ * @waiter:		the pre-initialized rt_mutex_waiter
+ *
+ * Attempt to clean up after a failed __rt_mutex_start_proxy_lock() or
+ * rt_mutex_wait_proxy_lock().
+ *
+ * Unless we acquired the lock; we're still enqueued on the wait-list and can
+ * in fact still be granted ownership until we're removed. Therefore we can
+ * find we are in fact the owner and must disregard the
+ * rt_mutex_wait_proxy_lock() failure.
+ *
+ * Returns:
+ *  true  - did the cleanup, we done.
+ *  false - we acquired the lock after rt_mutex_wait_proxy_lock() returned,
+ *          caller should disregards its return value.
+ *
+ * Special API call for PI-futex support
+ */
+bool __sched rt_mutex_cleanup_proxy_lock(struct rt_mutex_base *lock,
+					 struct rt_mutex_waiter *waiter)
+{
+	bool cleanup = false;
+
+	raw_spin_lock_irq(&lock->wait_lock);
+	/*
+	 * Do an unconditional try-lock, this deals with the lock stealing
+	 * state where __rt_mutex_futex_unlock() -> mark_wakeup_next_waiter()
+	 * sets a NULL owner.
+	 *
+	 * We're not interested in the return value, because the subsequent
+	 * test on rt_mutex_owner() will infer that. If the trylock succeeded,
+	 * we will own the lock and it will have removed the waiter. If we
+	 * failed the trylock, we're still not owner and we need to remove
+	 * ourselves.
+	 */
+	try_to_take_rt_mutex(lock, current, waiter);
+	/*
+	 * Unless we're the owner; we're still enqueued on the wait_list.
+	 * So check if we became owner, if not, take us off the wait_list.
+	 */
+	if (rt_mutex_owner(lock) != current) {
+		remove_waiter(lock, waiter);
+		cleanup = true;
+	}
+	/*
+	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
+	 * have to fix that up.
+	 */
+	fixup_rt_mutex_waiters(lock, false);
+
+	raw_spin_unlock_irq(&lock->wait_lock);
+
+	return cleanup;
+}
+
+/*
+ * Recheck the pi chain, in case we got a priority setting
+ *
+ * Called from sched_setscheduler
+ */
+void __sched rt_mutex_adjust_pi(struct task_struct *task)
+{
+	struct rt_mutex_waiter *waiter;
+	struct rt_mutex_base *next_lock;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&task->pi_lock, flags);
+
+	waiter = task->pi_blocked_on;
+	if (!waiter || rt_waiter_node_equal(&waiter->tree, task_to_waiter_node(task))) {
+		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+		return;
+	}
+	next_lock = waiter->lock;
+	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+
+	/* gets dropped in rt_mutex_adjust_prio_chain()! */
+	get_task_struct(task);
+
+	rt_mutex_adjust_prio_chain(task, RT_MUTEX_MIN_CHAINWALK, NULL,
+				   next_lock, NULL, task);
+}
+
+/*
+ * Performs the wakeup of the top-waiter and re-enables preemption.
+ */
+void __sched rt_mutex_postunlock(struct rt_wake_q_head *wqh)
+{
+	rt_mutex_wake_up_q(wqh);
+}
+
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+void rt_mutex_debug_task_free(struct task_struct *task)
+{
+	DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root));
+	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
+}
+#endif
+
+#ifdef CONFIG_PREEMPT_RT
+/* Mutexes */
+void __mutex_rt_init(struct mutex *mutex, const char *name,
+		     struct lock_class_key *key)
+{
+	debug_check_no_locks_freed((void *)mutex, sizeof(*mutex));
+	lockdep_init_map_wait(&mutex->dep_map, name, key, 0, LD_WAIT_SLEEP);
+}
+EXPORT_SYMBOL(__mutex_rt_init);
+
+static __always_inline int __mutex_lock_common(struct mutex *lock,
+					       unsigned int state,
+					       unsigned int subclass,
+					       struct lockdep_map *nest_lock,
+					       unsigned long ip)
+{
+	int ret;
+
+	might_sleep();
+	mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
+	ret = __rt_mutex_lock(&lock->rtmutex, state);
+	if (ret)
+		mutex_release(&lock->dep_map, ip);
+	else
+		lock_acquired(&lock->dep_map, ip);
+	return ret;
+}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __sched mutex_lock_nested(struct mutex *lock, unsigned int subclass)
+{
+	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_nested);
+
+void __sched _mutex_lock_nest_lock(struct mutex *lock,
+				   struct lockdep_map *nest_lock)
+{
+	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, nest_lock, _RET_IP_);
+}
+EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
+
+int __sched mutex_lock_interruptible_nested(struct mutex *lock,
+					    unsigned int subclass)
+{
+	return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, subclass, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
+
+int __sched mutex_lock_killable_nested(struct mutex *lock,
+					    unsigned int subclass)
+{
+	return __mutex_lock_common(lock, TASK_KILLABLE, subclass, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_killable_nested);
+
+void __sched mutex_lock_io_nested(struct mutex *lock, unsigned int subclass)
+{
+	int token;
+
+	might_sleep();
+
+	token = io_schedule_prepare();
+	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass, NULL, _RET_IP_);
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_io_nested);
+
+#else /* CONFIG_DEBUG_LOCK_ALLOC */
+
+void __sched mutex_lock(struct mutex *lock)
+{
+	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL(mutex_lock);
+
+int __sched mutex_lock_interruptible(struct mutex *lock)
+{
+	return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL(mutex_lock_interruptible);
+
+int __sched mutex_lock_killable(struct mutex *lock)
+{
+	return __mutex_lock_common(lock, TASK_KILLABLE, 0, NULL, _RET_IP_);
+}
+EXPORT_SYMBOL(mutex_lock_killable);
+
+void __sched mutex_lock_io(struct mutex *lock)
+{
+	int token = io_schedule_prepare();
+
+	__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, NULL, _RET_IP_);
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL(mutex_lock_io);
+#endif /* !CONFIG_DEBUG_LOCK_ALLOC */
+
+int __sched mutex_trylock(struct mutex *lock)
+{
+	int ret;
+
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task()))
+		return 0;
+
+	ret = __rt_mutex_trylock(&lock->rtmutex);
+	if (ret)
+		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+
+	return ret;
+}
+EXPORT_SYMBOL(mutex_trylock);
+
+void __sched mutex_unlock(struct mutex *lock)
+{
+	mutex_release(&lock->dep_map, _RET_IP_);
+	__rt_mutex_unlock(&lock->rtmutex);
+}
+EXPORT_SYMBOL(mutex_unlock);
+
+#endif /* CONFIG_PREEMPT_RT */
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
new file mode 100644
index 000000000..1162e07cd
--- /dev/null
+++ b/kernel/locking/rtmutex_common.h
@@ -0,0 +1,234 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * RT Mutexes: blocking mutual exclusion locks with PI support
+ *
+ * started by Ingo Molnar and Thomas Gleixner:
+ *
+ *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *
+ * This file contains the private data structure and API definitions.
+ */
+
+#ifndef __KERNEL_RTMUTEX_COMMON_H
+#define __KERNEL_RTMUTEX_COMMON_H
+
+#include <linux/debug_locks.h>
+#include <linux/rtmutex.h>
+#include <linux/sched/wake_q.h>
+
+
+/*
+ * This is a helper for the struct rt_mutex_waiter below. A waiter goes in two
+ * separate trees and they need their own copy of the sort keys because of
+ * different locking requirements.
+ *
+ * @entry:		rbtree node to enqueue into the waiters tree
+ * @prio:		Priority of the waiter
+ * @deadline:		Deadline of the waiter if applicable
+ *
+ * See rt_waiter_node_less() and waiter_*_prio().
+ */
+struct rt_waiter_node {
+	struct rb_node	entry;
+	int		prio;
+	u64		deadline;
+};
+
+/*
+ * This is the control structure for tasks blocked on a rt_mutex,
+ * which is allocated on the kernel stack on of the blocked task.
+ *
+ * @tree:		node to enqueue into the mutex waiters tree
+ * @pi_tree:		node to enqueue into the mutex owner waiters tree
+ * @task:		task reference to the blocked task
+ * @lock:		Pointer to the rt_mutex on which the waiter blocks
+ * @wake_state:		Wakeup state to use (TASK_NORMAL or TASK_RTLOCK_WAIT)
+ * @ww_ctx:		WW context pointer
+ *
+ * @tree is ordered by @lock->wait_lock
+ * @pi_tree is ordered by rt_mutex_owner(@lock)->pi_lock
+ */
+struct rt_mutex_waiter {
+	struct rt_waiter_node	tree;
+	struct rt_waiter_node	pi_tree;
+	struct task_struct	*task;
+	struct rt_mutex_base	*lock;
+	unsigned int		wake_state;
+	struct ww_acquire_ctx	*ww_ctx;
+};
+
+/**
+ * rt_wake_q_head - Wrapper around regular wake_q_head to support
+ *		    "sleeping" spinlocks on RT
+ * @head:		The regular wake_q_head for sleeping lock variants
+ * @rtlock_task:	Task pointer for RT lock (spin/rwlock) wakeups
+ */
+struct rt_wake_q_head {
+	struct wake_q_head	head;
+	struct task_struct	*rtlock_task;
+};
+
+#define DEFINE_RT_WAKE_Q(name)						\
+	struct rt_wake_q_head name = {					\
+		.head		= WAKE_Q_HEAD_INITIALIZER(name.head),	\
+		.rtlock_task	= NULL,					\
+	}
+
+/*
+ * PI-futex support (proxy locking functions, etc.):
+ */
+extern void rt_mutex_init_proxy_locked(struct rt_mutex_base *lock,
+				       struct task_struct *proxy_owner);
+extern void rt_mutex_proxy_unlock(struct rt_mutex_base *lock);
+extern int __rt_mutex_start_proxy_lock(struct rt_mutex_base *lock,
+				     struct rt_mutex_waiter *waiter,
+				     struct task_struct *task);
+extern int rt_mutex_start_proxy_lock(struct rt_mutex_base *lock,
+				     struct rt_mutex_waiter *waiter,
+				     struct task_struct *task);
+extern int rt_mutex_wait_proxy_lock(struct rt_mutex_base *lock,
+			       struct hrtimer_sleeper *to,
+			       struct rt_mutex_waiter *waiter);
+extern bool rt_mutex_cleanup_proxy_lock(struct rt_mutex_base *lock,
+				 struct rt_mutex_waiter *waiter);
+
+extern int rt_mutex_futex_trylock(struct rt_mutex_base *l);
+extern int __rt_mutex_futex_trylock(struct rt_mutex_base *l);
+
+extern void rt_mutex_futex_unlock(struct rt_mutex_base *lock);
+extern bool __rt_mutex_futex_unlock(struct rt_mutex_base *lock,
+				struct rt_wake_q_head *wqh);
+
+extern void rt_mutex_postunlock(struct rt_wake_q_head *wqh);
+
+/*
+ * Must be guarded because this header is included from rcu/tree_plugin.h
+ * unconditionally.
+ */
+#ifdef CONFIG_RT_MUTEXES
+static inline int rt_mutex_has_waiters(struct rt_mutex_base *lock)
+{
+	return !RB_EMPTY_ROOT(&lock->waiters.rb_root);
+}
+
+/*
+ * Lockless speculative check whether @waiter is still the top waiter on
+ * @lock. This is solely comparing pointers and not derefencing the
+ * leftmost entry which might be about to vanish.
+ */
+static inline bool rt_mutex_waiter_is_top_waiter(struct rt_mutex_base *lock,
+						 struct rt_mutex_waiter *waiter)
+{
+	struct rb_node *leftmost = rb_first_cached(&lock->waiters);
+
+	return rb_entry(leftmost, struct rt_mutex_waiter, tree.entry) == waiter;
+}
+
+static inline struct rt_mutex_waiter *rt_mutex_top_waiter(struct rt_mutex_base *lock)
+{
+	struct rb_node *leftmost = rb_first_cached(&lock->waiters);
+	struct rt_mutex_waiter *w = NULL;
+
+	lockdep_assert_held(&lock->wait_lock);
+
+	if (leftmost) {
+		w = rb_entry(leftmost, struct rt_mutex_waiter, tree.entry);
+		BUG_ON(w->lock != lock);
+	}
+	return w;
+}
+
+static inline int task_has_pi_waiters(struct task_struct *p)
+{
+	return !RB_EMPTY_ROOT(&p->pi_waiters.rb_root);
+}
+
+static inline struct rt_mutex_waiter *task_top_pi_waiter(struct task_struct *p)
+{
+	lockdep_assert_held(&p->pi_lock);
+
+	return rb_entry(p->pi_waiters.rb_leftmost, struct rt_mutex_waiter,
+			pi_tree.entry);
+}
+
+#define RT_MUTEX_HAS_WAITERS	1UL
+
+static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock)
+{
+	unsigned long owner = (unsigned long) READ_ONCE(lock->owner);
+
+	return (struct task_struct *) (owner & ~RT_MUTEX_HAS_WAITERS);
+}
+
+/*
+ * Constants for rt mutex functions which have a selectable deadlock
+ * detection.
+ *
+ * RT_MUTEX_MIN_CHAINWALK:	Stops the lock chain walk when there are
+ *				no further PI adjustments to be made.
+ *
+ * RT_MUTEX_FULL_CHAINWALK:	Invoke deadlock detection with a full
+ *				walk of the lock chain.
+ */
+enum rtmutex_chainwalk {
+	RT_MUTEX_MIN_CHAINWALK,
+	RT_MUTEX_FULL_CHAINWALK,
+};
+
+static inline void __rt_mutex_base_init(struct rt_mutex_base *lock)
+{
+	raw_spin_lock_init(&lock->wait_lock);
+	lock->waiters = RB_ROOT_CACHED;
+	lock->owner = NULL;
+}
+
+/* Debug functions */
+static inline void debug_rt_mutex_unlock(struct rt_mutex_base *lock)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);
+}
+
+static inline void debug_rt_mutex_proxy_unlock(struct rt_mutex_base *lock)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));
+}
+
+static inline void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		memset(waiter, 0x11, sizeof(*waiter));
+}
+
+static inline void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))
+		memset(waiter, 0x22, sizeof(*waiter));
+}
+
+static inline void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+{
+	debug_rt_mutex_init_waiter(waiter);
+	RB_CLEAR_NODE(&waiter->pi_tree.entry);
+	RB_CLEAR_NODE(&waiter->tree.entry);
+	waiter->wake_state = TASK_NORMAL;
+	waiter->task = NULL;
+}
+
+static inline void rt_mutex_init_rtlock_waiter(struct rt_mutex_waiter *waiter)
+{
+	rt_mutex_init_waiter(waiter);
+	waiter->wake_state = TASK_RTLOCK_WAIT;
+}
+
+#else /* CONFIG_RT_MUTEXES */
+/* Used in rcu/tree_plugin.h */
+static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock)
+{
+	return NULL;
+}
+#endif  /* !CONFIG_RT_MUTEXES */
+
+#endif
diff --git a/kernel/locking/rwbase_rt.c b/kernel/locking/rwbase_rt.c
new file mode 100644
index 000000000..c201aadb9
--- /dev/null
+++ b/kernel/locking/rwbase_rt.c
@@ -0,0 +1,298 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * RT-specific reader/writer semaphores and reader/writer locks
+ *
+ * down_write/write_lock()
+ *  1) Lock rtmutex
+ *  2) Remove the reader BIAS to force readers into the slow path
+ *  3) Wait until all readers have left the critical section
+ *  4) Mark it write locked
+ *
+ * up_write/write_unlock()
+ *  1) Remove the write locked marker
+ *  2) Set the reader BIAS, so readers can use the fast path again
+ *  3) Unlock rtmutex, to release blocked readers
+ *
+ * down_read/read_lock()
+ *  1) Try fast path acquisition (reader BIAS is set)
+ *  2) Take tmutex::wait_lock, which protects the writelocked flag
+ *  3) If !writelocked, acquire it for read
+ *  4) If writelocked, block on tmutex
+ *  5) unlock rtmutex, goto 1)
+ *
+ * up_read/read_unlock()
+ *  1) Try fast path release (reader count != 1)
+ *  2) Wake the writer waiting in down_write()/write_lock() #3
+ *
+ * down_read/read_lock()#3 has the consequence, that rw semaphores and rw
+ * locks on RT are not writer fair, but writers, which should be avoided in
+ * RT tasks (think mmap_sem), are subject to the rtmutex priority/DL
+ * inheritance mechanism.
+ *
+ * It's possible to make the rw primitives writer fair by keeping a list of
+ * active readers. A blocked writer would force all newly incoming readers
+ * to block on the rtmutex, but the rtmutex would have to be proxy locked
+ * for one reader after the other. We can't use multi-reader inheritance
+ * because there is no way to support that with SCHED_DEADLINE.
+ * Implementing the one by one reader boosting/handover mechanism is a
+ * major surgery for a very dubious value.
+ *
+ * The risk of writer starvation is there, but the pathological use cases
+ * which trigger it are not necessarily the typical RT workloads.
+ *
+ * Fast-path orderings:
+ * The lock/unlock of readers can run in fast paths: lock and unlock are only
+ * atomic ops, and there is no inner lock to provide ACQUIRE and RELEASE
+ * semantics of rwbase_rt. Atomic ops should thus provide _acquire()
+ * and _release() (or stronger).
+ *
+ * Common code shared between RT rw_semaphore and rwlock
+ */
+
+static __always_inline int rwbase_read_trylock(struct rwbase_rt *rwb)
+{
+	int r;
+
+	/*
+	 * Increment reader count, if sem->readers < 0, i.e. READER_BIAS is
+	 * set.
+	 */
+	for (r = atomic_read(&rwb->readers); r < 0;) {
+		if (likely(atomic_try_cmpxchg_acquire(&rwb->readers, &r, r + 1)))
+			return 1;
+	}
+	return 0;
+}
+
+static int __sched __rwbase_read_lock(struct rwbase_rt *rwb,
+				      unsigned int state)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+	int ret;
+
+	raw_spin_lock_irq(&rtm->wait_lock);
+	/*
+	 * Allow readers, as long as the writer has not completely
+	 * acquired the semaphore for write.
+	 */
+	if (atomic_read(&rwb->readers) != WRITER_BIAS) {
+		atomic_inc(&rwb->readers);
+		raw_spin_unlock_irq(&rtm->wait_lock);
+		return 0;
+	}
+
+	/*
+	 * Call into the slow lock path with the rtmutex->wait_lock
+	 * held, so this can't result in the following race:
+	 *
+	 * Reader1		Reader2		Writer
+	 *			down_read()
+	 *					down_write()
+	 *					rtmutex_lock(m)
+	 *					wait()
+	 * down_read()
+	 * unlock(m->wait_lock)
+	 *			up_read()
+	 *			wake(Writer)
+	 *					lock(m->wait_lock)
+	 *					sem->writelocked=true
+	 *					unlock(m->wait_lock)
+	 *
+	 *					up_write()
+	 *					sem->writelocked=false
+	 *					rtmutex_unlock(m)
+	 *			down_read()
+	 *					down_write()
+	 *					rtmutex_lock(m)
+	 *					wait()
+	 * rtmutex_lock(m)
+	 *
+	 * That would put Reader1 behind the writer waiting on
+	 * Reader2 to call up_read(), which might be unbound.
+	 */
+
+	trace_contention_begin(rwb, LCB_F_RT | LCB_F_READ);
+
+	/*
+	 * For rwlocks this returns 0 unconditionally, so the below
+	 * !ret conditionals are optimized out.
+	 */
+	ret = rwbase_rtmutex_slowlock_locked(rtm, state);
+
+	/*
+	 * On success the rtmutex is held, so there can't be a writer
+	 * active. Increment the reader count and immediately drop the
+	 * rtmutex again.
+	 *
+	 * rtmutex->wait_lock has to be unlocked in any case of course.
+	 */
+	if (!ret)
+		atomic_inc(&rwb->readers);
+	raw_spin_unlock_irq(&rtm->wait_lock);
+	if (!ret)
+		rwbase_rtmutex_unlock(rtm);
+
+	trace_contention_end(rwb, ret);
+	return ret;
+}
+
+static __always_inline int rwbase_read_lock(struct rwbase_rt *rwb,
+					    unsigned int state)
+{
+	if (rwbase_read_trylock(rwb))
+		return 0;
+
+	return __rwbase_read_lock(rwb, state);
+}
+
+static void __sched __rwbase_read_unlock(struct rwbase_rt *rwb,
+					 unsigned int state)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+	struct task_struct *owner;
+	DEFINE_RT_WAKE_Q(wqh);
+
+	raw_spin_lock_irq(&rtm->wait_lock);
+	/*
+	 * Wake the writer, i.e. the rtmutex owner. It might release the
+	 * rtmutex concurrently in the fast path (due to a signal), but to
+	 * clean up rwb->readers it needs to acquire rtm->wait_lock. The
+	 * worst case which can happen is a spurious wakeup.
+	 */
+	owner = rt_mutex_owner(rtm);
+	if (owner)
+		rt_mutex_wake_q_add_task(&wqh, owner, state);
+
+	/* Pairs with the preempt_enable in rt_mutex_wake_up_q() */
+	preempt_disable();
+	raw_spin_unlock_irq(&rtm->wait_lock);
+	rt_mutex_wake_up_q(&wqh);
+}
+
+static __always_inline void rwbase_read_unlock(struct rwbase_rt *rwb,
+					       unsigned int state)
+{
+	/*
+	 * rwb->readers can only hit 0 when a writer is waiting for the
+	 * active readers to leave the critical section.
+	 *
+	 * dec_and_test() is fully ordered, provides RELEASE.
+	 */
+	if (unlikely(atomic_dec_and_test(&rwb->readers)))
+		__rwbase_read_unlock(rwb, state);
+}
+
+static inline void __rwbase_write_unlock(struct rwbase_rt *rwb, int bias,
+					 unsigned long flags)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+
+	/*
+	 * _release() is needed in case that reader is in fast path, pairing
+	 * with atomic_try_cmpxchg_acquire() in rwbase_read_trylock().
+	 */
+	(void)atomic_add_return_release(READER_BIAS - bias, &rwb->readers);
+	raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);
+	rwbase_rtmutex_unlock(rtm);
+}
+
+static inline void rwbase_write_unlock(struct rwbase_rt *rwb)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&rtm->wait_lock, flags);
+	__rwbase_write_unlock(rwb, WRITER_BIAS, flags);
+}
+
+static inline void rwbase_write_downgrade(struct rwbase_rt *rwb)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&rtm->wait_lock, flags);
+	/* Release it and account current as reader */
+	__rwbase_write_unlock(rwb, WRITER_BIAS - 1, flags);
+}
+
+static inline bool __rwbase_write_trylock(struct rwbase_rt *rwb)
+{
+	/* Can do without CAS because we're serialized by wait_lock. */
+	lockdep_assert_held(&rwb->rtmutex.wait_lock);
+
+	/*
+	 * _acquire is needed in case the reader is in the fast path, pairing
+	 * with rwbase_read_unlock(), provides ACQUIRE.
+	 */
+	if (!atomic_read_acquire(&rwb->readers)) {
+		atomic_set(&rwb->readers, WRITER_BIAS);
+		return 1;
+	}
+
+	return 0;
+}
+
+static int __sched rwbase_write_lock(struct rwbase_rt *rwb,
+				     unsigned int state)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+	unsigned long flags;
+
+	/* Take the rtmutex as a first step */
+	if (rwbase_rtmutex_lock_state(rtm, state))
+		return -EINTR;
+
+	/* Force readers into slow path */
+	atomic_sub(READER_BIAS, &rwb->readers);
+
+	raw_spin_lock_irqsave(&rtm->wait_lock, flags);
+	if (__rwbase_write_trylock(rwb))
+		goto out_unlock;
+
+	rwbase_set_and_save_current_state(state);
+	trace_contention_begin(rwb, LCB_F_RT | LCB_F_WRITE);
+	for (;;) {
+		/* Optimized out for rwlocks */
+		if (rwbase_signal_pending_state(state, current)) {
+			rwbase_restore_current_state();
+			__rwbase_write_unlock(rwb, 0, flags);
+			trace_contention_end(rwb, -EINTR);
+			return -EINTR;
+		}
+
+		if (__rwbase_write_trylock(rwb))
+			break;
+
+		raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);
+		rwbase_schedule();
+		raw_spin_lock_irqsave(&rtm->wait_lock, flags);
+
+		set_current_state(state);
+	}
+	rwbase_restore_current_state();
+	trace_contention_end(rwb, 0);
+
+out_unlock:
+	raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);
+	return 0;
+}
+
+static inline int rwbase_write_trylock(struct rwbase_rt *rwb)
+{
+	struct rt_mutex_base *rtm = &rwb->rtmutex;
+	unsigned long flags;
+
+	if (!rwbase_rtmutex_trylock(rtm))
+		return 0;
+
+	atomic_sub(READER_BIAS, &rwb->readers);
+
+	raw_spin_lock_irqsave(&rtm->wait_lock, flags);
+	if (__rwbase_write_trylock(rwb)) {
+		raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);
+		return 1;
+	}
+	__rwbase_write_unlock(rwb, 0, flags);
+	return 0;
+}
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
new file mode 100644
index 000000000..92d8e2c4e
--- /dev/null
+++ b/kernel/locking/rwsem.c
@@ -0,0 +1,1716 @@
+// SPDX-License-Identifier: GPL-2.0
+/* kernel/rwsem.c: R/W semaphores, public implementation
+ *
+ * Written by David Howells (dhowells@redhat.com).
+ * Derived from asm-i386/semaphore.h
+ *
+ * Writer lock-stealing by Alex Shi <alex.shi@intel.com>
+ * and Michel Lespinasse <walken@google.com>
+ *
+ * Optimistic spinning by Tim Chen <tim.c.chen@intel.com>
+ * and Davidlohr Bueso <davidlohr@hp.com>. Based on mutexes.
+ *
+ * Rwsem count bit fields re-definition and rwsem rearchitecture by
+ * Waiman Long <longman@redhat.com> and
+ * Peter Zijlstra <peterz@infradead.org>.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/sched/rt.h>
+#include <linux/sched/task.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/wake_q.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/clock.h>
+#include <linux/export.h>
+#include <linux/rwsem.h>
+#include <linux/atomic.h>
+#include <trace/events/lock.h>
+
+#ifndef CONFIG_PREEMPT_RT
+#include "lock_events.h"
+
+/*
+ * The least significant 2 bits of the owner value has the following
+ * meanings when set.
+ *  - Bit 0: RWSEM_READER_OWNED - The rwsem is owned by readers
+ *  - Bit 1: RWSEM_NONSPINNABLE - Cannot spin on a reader-owned lock
+ *
+ * When the rwsem is reader-owned and a spinning writer has timed out,
+ * the nonspinnable bit will be set to disable optimistic spinning.
+
+ * When a writer acquires a rwsem, it puts its task_struct pointer
+ * into the owner field. It is cleared after an unlock.
+ *
+ * When a reader acquires a rwsem, it will also puts its task_struct
+ * pointer into the owner field with the RWSEM_READER_OWNED bit set.
+ * On unlock, the owner field will largely be left untouched. So
+ * for a free or reader-owned rwsem, the owner value may contain
+ * information about the last reader that acquires the rwsem.
+ *
+ * That information may be helpful in debugging cases where the system
+ * seems to hang on a reader owned rwsem especially if only one reader
+ * is involved. Ideally we would like to track all the readers that own
+ * a rwsem, but the overhead is simply too big.
+ *
+ * A fast path reader optimistic lock stealing is supported when the rwsem
+ * is previously owned by a writer and the following conditions are met:
+ *  - rwsem is not currently writer owned
+ *  - the handoff isn't set.
+ */
+#define RWSEM_READER_OWNED	(1UL << 0)
+#define RWSEM_NONSPINNABLE	(1UL << 1)
+#define RWSEM_OWNER_FLAGS_MASK	(RWSEM_READER_OWNED | RWSEM_NONSPINNABLE)
+
+#ifdef CONFIG_DEBUG_RWSEMS
+# define DEBUG_RWSEMS_WARN_ON(c, sem)	do {			\
+	if (!debug_locks_silent &&				\
+	    WARN_ONCE(c, "DEBUG_RWSEMS_WARN_ON(%s): count = 0x%lx, magic = 0x%lx, owner = 0x%lx, curr 0x%lx, list %sempty\n",\
+		#c, atomic_long_read(&(sem)->count),		\
+		(unsigned long) sem->magic,			\
+		atomic_long_read(&(sem)->owner), (long)current,	\
+		list_empty(&(sem)->wait_list) ? "" : "not "))	\
+			debug_locks_off();			\
+	} while (0)
+#else
+# define DEBUG_RWSEMS_WARN_ON(c, sem)
+#endif
+
+/*
+ * On 64-bit architectures, the bit definitions of the count are:
+ *
+ * Bit  0    - writer locked bit
+ * Bit  1    - waiters present bit
+ * Bit  2    - lock handoff bit
+ * Bits 3-7  - reserved
+ * Bits 8-62 - 55-bit reader count
+ * Bit  63   - read fail bit
+ *
+ * On 32-bit architectures, the bit definitions of the count are:
+ *
+ * Bit  0    - writer locked bit
+ * Bit  1    - waiters present bit
+ * Bit  2    - lock handoff bit
+ * Bits 3-7  - reserved
+ * Bits 8-30 - 23-bit reader count
+ * Bit  31   - read fail bit
+ *
+ * It is not likely that the most significant bit (read fail bit) will ever
+ * be set. This guard bit is still checked anyway in the down_read() fastpath
+ * just in case we need to use up more of the reader bits for other purpose
+ * in the future.
+ *
+ * atomic_long_fetch_add() is used to obtain reader lock, whereas
+ * atomic_long_cmpxchg() will be used to obtain writer lock.
+ *
+ * There are three places where the lock handoff bit may be set or cleared.
+ * 1) rwsem_mark_wake() for readers		-- set, clear
+ * 2) rwsem_try_write_lock() for writers	-- set, clear
+ * 3) rwsem_del_waiter()			-- clear
+ *
+ * For all the above cases, wait_lock will be held. A writer must also
+ * be the first one in the wait_list to be eligible for setting the handoff
+ * bit. So concurrent setting/clearing of handoff bit is not possible.
+ */
+#define RWSEM_WRITER_LOCKED	(1UL << 0)
+#define RWSEM_FLAG_WAITERS	(1UL << 1)
+#define RWSEM_FLAG_HANDOFF	(1UL << 2)
+#define RWSEM_FLAG_READFAIL	(1UL << (BITS_PER_LONG - 1))
+
+#define RWSEM_READER_SHIFT	8
+#define RWSEM_READER_BIAS	(1UL << RWSEM_READER_SHIFT)
+#define RWSEM_READER_MASK	(~(RWSEM_READER_BIAS - 1))
+#define RWSEM_WRITER_MASK	RWSEM_WRITER_LOCKED
+#define RWSEM_LOCK_MASK		(RWSEM_WRITER_MASK|RWSEM_READER_MASK)
+#define RWSEM_READ_FAILED_MASK	(RWSEM_WRITER_MASK|RWSEM_FLAG_WAITERS|\
+				 RWSEM_FLAG_HANDOFF|RWSEM_FLAG_READFAIL)
+
+/*
+ * All writes to owner are protected by WRITE_ONCE() to make sure that
+ * store tearing can't happen as optimistic spinners may read and use
+ * the owner value concurrently without lock. Read from owner, however,
+ * may not need READ_ONCE() as long as the pointer value is only used
+ * for comparison and isn't being dereferenced.
+ *
+ * Both rwsem_{set,clear}_owner() functions should be in the same
+ * preempt disable section as the atomic op that changes sem->count.
+ */
+static inline void rwsem_set_owner(struct rw_semaphore *sem)
+{
+	lockdep_assert_preemption_disabled();
+	atomic_long_set(&sem->owner, (long)current);
+}
+
+static inline void rwsem_clear_owner(struct rw_semaphore *sem)
+{
+	lockdep_assert_preemption_disabled();
+	atomic_long_set(&sem->owner, 0);
+}
+
+/*
+ * Test the flags in the owner field.
+ */
+static inline bool rwsem_test_oflags(struct rw_semaphore *sem, long flags)
+{
+	return atomic_long_read(&sem->owner) & flags;
+}
+
+/*
+ * The task_struct pointer of the last owning reader will be left in
+ * the owner field.
+ *
+ * Note that the owner value just indicates the task has owned the rwsem
+ * previously, it may not be the real owner or one of the real owners
+ * anymore when that field is examined, so take it with a grain of salt.
+ *
+ * The reader non-spinnable bit is preserved.
+ */
+static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem,
+					    struct task_struct *owner)
+{
+	unsigned long val = (unsigned long)owner | RWSEM_READER_OWNED |
+		(atomic_long_read(&sem->owner) & RWSEM_NONSPINNABLE);
+
+	atomic_long_set(&sem->owner, val);
+}
+
+static inline void rwsem_set_reader_owned(struct rw_semaphore *sem)
+{
+	__rwsem_set_reader_owned(sem, current);
+}
+
+/*
+ * Return true if the rwsem is owned by a reader.
+ */
+static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
+{
+#ifdef CONFIG_DEBUG_RWSEMS
+	/*
+	 * Check the count to see if it is write-locked.
+	 */
+	long count = atomic_long_read(&sem->count);
+
+	if (count & RWSEM_WRITER_MASK)
+		return false;
+#endif
+	return rwsem_test_oflags(sem, RWSEM_READER_OWNED);
+}
+
+#ifdef CONFIG_DEBUG_RWSEMS
+/*
+ * With CONFIG_DEBUG_RWSEMS configured, it will make sure that if there
+ * is a task pointer in owner of a reader-owned rwsem, it will be the
+ * real owner or one of the real owners. The only exception is when the
+ * unlock is done by up_read_non_owner().
+ */
+static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem)
+{
+	unsigned long val = atomic_long_read(&sem->owner);
+
+	while ((val & ~RWSEM_OWNER_FLAGS_MASK) == (unsigned long)current) {
+		if (atomic_long_try_cmpxchg(&sem->owner, &val,
+					    val & RWSEM_OWNER_FLAGS_MASK))
+			return;
+	}
+}
+#else
+static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem)
+{
+}
+#endif
+
+/*
+ * Set the RWSEM_NONSPINNABLE bits if the RWSEM_READER_OWNED flag
+ * remains set. Otherwise, the operation will be aborted.
+ */
+static inline void rwsem_set_nonspinnable(struct rw_semaphore *sem)
+{
+	unsigned long owner = atomic_long_read(&sem->owner);
+
+	do {
+		if (!(owner & RWSEM_READER_OWNED))
+			break;
+		if (owner & RWSEM_NONSPINNABLE)
+			break;
+	} while (!atomic_long_try_cmpxchg(&sem->owner, &owner,
+					  owner | RWSEM_NONSPINNABLE));
+}
+
+static inline bool rwsem_read_trylock(struct rw_semaphore *sem, long *cntp)
+{
+	*cntp = atomic_long_add_return_acquire(RWSEM_READER_BIAS, &sem->count);
+
+	if (WARN_ON_ONCE(*cntp < 0))
+		rwsem_set_nonspinnable(sem);
+
+	if (!(*cntp & RWSEM_READ_FAILED_MASK)) {
+		rwsem_set_reader_owned(sem);
+		return true;
+	}
+
+	return false;
+}
+
+static inline bool rwsem_write_trylock(struct rw_semaphore *sem)
+{
+	long tmp = RWSEM_UNLOCKED_VALUE;
+	bool ret = false;
+
+	preempt_disable();
+	if (atomic_long_try_cmpxchg_acquire(&sem->count, &tmp, RWSEM_WRITER_LOCKED)) {
+		rwsem_set_owner(sem);
+		ret = true;
+	}
+
+	preempt_enable();
+	return ret;
+}
+
+/*
+ * Return just the real task structure pointer of the owner
+ */
+static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
+{
+	return (struct task_struct *)
+		(atomic_long_read(&sem->owner) & ~RWSEM_OWNER_FLAGS_MASK);
+}
+
+/*
+ * Return the real task structure pointer of the owner and the embedded
+ * flags in the owner. pflags must be non-NULL.
+ */
+static inline struct task_struct *
+rwsem_owner_flags(struct rw_semaphore *sem, unsigned long *pflags)
+{
+	unsigned long owner = atomic_long_read(&sem->owner);
+
+	*pflags = owner & RWSEM_OWNER_FLAGS_MASK;
+	return (struct task_struct *)(owner & ~RWSEM_OWNER_FLAGS_MASK);
+}
+
+/*
+ * Guide to the rw_semaphore's count field.
+ *
+ * When the RWSEM_WRITER_LOCKED bit in count is set, the lock is owned
+ * by a writer.
+ *
+ * The lock is owned by readers when
+ * (1) the RWSEM_WRITER_LOCKED isn't set in count,
+ * (2) some of the reader bits are set in count, and
+ * (3) the owner field has RWSEM_READ_OWNED bit set.
+ *
+ * Having some reader bits set is not enough to guarantee a readers owned
+ * lock as the readers may be in the process of backing out from the count
+ * and a writer has just released the lock. So another writer may steal
+ * the lock immediately after that.
+ */
+
+/*
+ * Initialize an rwsem:
+ */
+void __init_rwsem(struct rw_semaphore *sem, const char *name,
+		  struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held semaphore:
+	 */
+	debug_check_no_locks_freed((void *)sem, sizeof(*sem));
+	lockdep_init_map_wait(&sem->dep_map, name, key, 0, LD_WAIT_SLEEP);
+#endif
+#ifdef CONFIG_DEBUG_RWSEMS
+	sem->magic = sem;
+#endif
+	atomic_long_set(&sem->count, RWSEM_UNLOCKED_VALUE);
+	raw_spin_lock_init(&sem->wait_lock);
+	INIT_LIST_HEAD(&sem->wait_list);
+	atomic_long_set(&sem->owner, 0L);
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
+	osq_lock_init(&sem->osq);
+#endif
+}
+EXPORT_SYMBOL(__init_rwsem);
+
+enum rwsem_waiter_type {
+	RWSEM_WAITING_FOR_WRITE,
+	RWSEM_WAITING_FOR_READ
+};
+
+struct rwsem_waiter {
+	struct list_head list;
+	struct task_struct *task;
+	enum rwsem_waiter_type type;
+	unsigned long timeout;
+	bool handoff_set;
+};
+#define rwsem_first_waiter(sem) \
+	list_first_entry(&sem->wait_list, struct rwsem_waiter, list)
+
+enum rwsem_wake_type {
+	RWSEM_WAKE_ANY,		/* Wake whatever's at head of wait list */
+	RWSEM_WAKE_READERS,	/* Wake readers only */
+	RWSEM_WAKE_READ_OWNED	/* Waker thread holds the read lock */
+};
+
+/*
+ * The typical HZ value is either 250 or 1000. So set the minimum waiting
+ * time to at least 4ms or 1 jiffy (if it is higher than 4ms) in the wait
+ * queue before initiating the handoff protocol.
+ */
+#define RWSEM_WAIT_TIMEOUT	DIV_ROUND_UP(HZ, 250)
+
+/*
+ * Magic number to batch-wakeup waiting readers, even when writers are
+ * also present in the queue. This both limits the amount of work the
+ * waking thread must do and also prevents any potential counter overflow,
+ * however unlikely.
+ */
+#define MAX_READERS_WAKEUP	0x100
+
+static inline void
+rwsem_add_waiter(struct rw_semaphore *sem, struct rwsem_waiter *waiter)
+{
+	lockdep_assert_held(&sem->wait_lock);
+	list_add_tail(&waiter->list, &sem->wait_list);
+	/* caller will set RWSEM_FLAG_WAITERS */
+}
+
+/*
+ * Remove a waiter from the wait_list and clear flags.
+ *
+ * Both rwsem_mark_wake() and rwsem_try_write_lock() contain a full 'copy' of
+ * this function. Modify with care.
+ *
+ * Return: true if wait_list isn't empty and false otherwise
+ */
+static inline bool
+rwsem_del_waiter(struct rw_semaphore *sem, struct rwsem_waiter *waiter)
+{
+	lockdep_assert_held(&sem->wait_lock);
+	list_del(&waiter->list);
+	if (likely(!list_empty(&sem->wait_list)))
+		return true;
+
+	atomic_long_andnot(RWSEM_FLAG_HANDOFF | RWSEM_FLAG_WAITERS, &sem->count);
+	return false;
+}
+
+/*
+ * handle the lock release when processes blocked on it that can now run
+ * - if we come here from up_xxxx(), then the RWSEM_FLAG_WAITERS bit must
+ *   have been set.
+ * - there must be someone on the queue
+ * - the wait_lock must be held by the caller
+ * - tasks are marked for wakeup, the caller must later invoke wake_up_q()
+ *   to actually wakeup the blocked task(s) and drop the reference count,
+ *   preferably when the wait_lock is released
+ * - woken process blocks are discarded from the list after having task zeroed
+ * - writers are only marked woken if downgrading is false
+ *
+ * Implies rwsem_del_waiter() for all woken readers.
+ */
+static void rwsem_mark_wake(struct rw_semaphore *sem,
+			    enum rwsem_wake_type wake_type,
+			    struct wake_q_head *wake_q)
+{
+	struct rwsem_waiter *waiter, *tmp;
+	long oldcount, woken = 0, adjustment = 0;
+	struct list_head wlist;
+
+	lockdep_assert_held(&sem->wait_lock);
+
+	/*
+	 * Take a peek at the queue head waiter such that we can determine
+	 * the wakeup(s) to perform.
+	 */
+	waiter = rwsem_first_waiter(sem);
+
+	if (waiter->type == RWSEM_WAITING_FOR_WRITE) {
+		if (wake_type == RWSEM_WAKE_ANY) {
+			/*
+			 * Mark writer at the front of the queue for wakeup.
+			 * Until the task is actually later awoken later by
+			 * the caller, other writers are able to steal it.
+			 * Readers, on the other hand, will block as they
+			 * will notice the queued writer.
+			 */
+			wake_q_add(wake_q, waiter->task);
+			lockevent_inc(rwsem_wake_writer);
+		}
+
+		return;
+	}
+
+	/*
+	 * No reader wakeup if there are too many of them already.
+	 */
+	if (unlikely(atomic_long_read(&sem->count) < 0))
+		return;
+
+	/*
+	 * Writers might steal the lock before we grant it to the next reader.
+	 * We prefer to do the first reader grant before counting readers
+	 * so we can bail out early if a writer stole the lock.
+	 */
+	if (wake_type != RWSEM_WAKE_READ_OWNED) {
+		struct task_struct *owner;
+
+		adjustment = RWSEM_READER_BIAS;
+		oldcount = atomic_long_fetch_add(adjustment, &sem->count);
+		if (unlikely(oldcount & RWSEM_WRITER_MASK)) {
+			/*
+			 * When we've been waiting "too" long (for writers
+			 * to give up the lock), request a HANDOFF to
+			 * force the issue.
+			 */
+			if (time_after(jiffies, waiter->timeout)) {
+				if (!(oldcount & RWSEM_FLAG_HANDOFF)) {
+					adjustment -= RWSEM_FLAG_HANDOFF;
+					lockevent_inc(rwsem_rlock_handoff);
+				}
+				waiter->handoff_set = true;
+			}
+
+			atomic_long_add(-adjustment, &sem->count);
+			return;
+		}
+		/*
+		 * Set it to reader-owned to give spinners an early
+		 * indication that readers now have the lock.
+		 * The reader nonspinnable bit seen at slowpath entry of
+		 * the reader is copied over.
+		 */
+		owner = waiter->task;
+		__rwsem_set_reader_owned(sem, owner);
+	}
+
+	/*
+	 * Grant up to MAX_READERS_WAKEUP read locks to all the readers in the
+	 * queue. We know that the woken will be at least 1 as we accounted
+	 * for above. Note we increment the 'active part' of the count by the
+	 * number of readers before waking any processes up.
+	 *
+	 * This is an adaptation of the phase-fair R/W locks where at the
+	 * reader phase (first waiter is a reader), all readers are eligible
+	 * to acquire the lock at the same time irrespective of their order
+	 * in the queue. The writers acquire the lock according to their
+	 * order in the queue.
+	 *
+	 * We have to do wakeup in 2 passes to prevent the possibility that
+	 * the reader count may be decremented before it is incremented. It
+	 * is because the to-be-woken waiter may not have slept yet. So it
+	 * may see waiter->task got cleared, finish its critical section and
+	 * do an unlock before the reader count increment.
+	 *
+	 * 1) Collect the read-waiters in a separate list, count them and
+	 *    fully increment the reader count in rwsem.
+	 * 2) For each waiters in the new list, clear waiter->task and
+	 *    put them into wake_q to be woken up later.
+	 */
+	INIT_LIST_HEAD(&wlist);
+	list_for_each_entry_safe(waiter, tmp, &sem->wait_list, list) {
+		if (waiter->type == RWSEM_WAITING_FOR_WRITE)
+			continue;
+
+		woken++;
+		list_move_tail(&waiter->list, &wlist);
+
+		/*
+		 * Limit # of readers that can be woken up per wakeup call.
+		 */
+		if (unlikely(woken >= MAX_READERS_WAKEUP))
+			break;
+	}
+
+	adjustment = woken * RWSEM_READER_BIAS - adjustment;
+	lockevent_cond_inc(rwsem_wake_reader, woken);
+
+	oldcount = atomic_long_read(&sem->count);
+	if (list_empty(&sem->wait_list)) {
+		/*
+		 * Combined with list_move_tail() above, this implies
+		 * rwsem_del_waiter().
+		 */
+		adjustment -= RWSEM_FLAG_WAITERS;
+		if (oldcount & RWSEM_FLAG_HANDOFF)
+			adjustment -= RWSEM_FLAG_HANDOFF;
+	} else if (woken) {
+		/*
+		 * When we've woken a reader, we no longer need to force
+		 * writers to give up the lock and we can clear HANDOFF.
+		 */
+		if (oldcount & RWSEM_FLAG_HANDOFF)
+			adjustment -= RWSEM_FLAG_HANDOFF;
+	}
+
+	if (adjustment)
+		atomic_long_add(adjustment, &sem->count);
+
+	/* 2nd pass */
+	list_for_each_entry_safe(waiter, tmp, &wlist, list) {
+		struct task_struct *tsk;
+
+		tsk = waiter->task;
+		get_task_struct(tsk);
+
+		/*
+		 * Ensure calling get_task_struct() before setting the reader
+		 * waiter to nil such that rwsem_down_read_slowpath() cannot
+		 * race with do_exit() by always holding a reference count
+		 * to the task to wakeup.
+		 */
+		smp_store_release(&waiter->task, NULL);
+		/*
+		 * Ensure issuing the wakeup (either by us or someone else)
+		 * after setting the reader waiter to nil.
+		 */
+		wake_q_add_safe(wake_q, tsk);
+	}
+}
+
+/*
+ * Remove a waiter and try to wake up other waiters in the wait queue
+ * This function is called from the out_nolock path of both the reader and
+ * writer slowpaths with wait_lock held. It releases the wait_lock and
+ * optionally wake up waiters before it returns.
+ */
+static inline void
+rwsem_del_wake_waiter(struct rw_semaphore *sem, struct rwsem_waiter *waiter,
+		      struct wake_q_head *wake_q)
+		      __releases(&sem->wait_lock)
+{
+	bool first = rwsem_first_waiter(sem) == waiter;
+
+	wake_q_init(wake_q);
+
+	/*
+	 * If the wait_list isn't empty and the waiter to be deleted is
+	 * the first waiter, we wake up the remaining waiters as they may
+	 * be eligible to acquire or spin on the lock.
+	 */
+	if (rwsem_del_waiter(sem, waiter) && first)
+		rwsem_mark_wake(sem, RWSEM_WAKE_ANY, wake_q);
+	raw_spin_unlock_irq(&sem->wait_lock);
+	if (!wake_q_empty(wake_q))
+		wake_up_q(wake_q);
+}
+
+/*
+ * This function must be called with the sem->wait_lock held to prevent
+ * race conditions between checking the rwsem wait list and setting the
+ * sem->count accordingly.
+ *
+ * Implies rwsem_del_waiter() on success.
+ */
+static inline bool rwsem_try_write_lock(struct rw_semaphore *sem,
+					struct rwsem_waiter *waiter)
+{
+	struct rwsem_waiter *first = rwsem_first_waiter(sem);
+	long count, new;
+
+	lockdep_assert_held(&sem->wait_lock);
+
+	count = atomic_long_read(&sem->count);
+	do {
+		bool has_handoff = !!(count & RWSEM_FLAG_HANDOFF);
+
+		if (has_handoff) {
+			/*
+			 * Honor handoff bit and yield only when the first
+			 * waiter is the one that set it. Otherwisee, we
+			 * still try to acquire the rwsem.
+			 */
+			if (first->handoff_set && (waiter != first))
+				return false;
+		}
+
+		new = count;
+
+		if (count & RWSEM_LOCK_MASK) {
+			/*
+			 * A waiter (first or not) can set the handoff bit
+			 * if it is an RT task or wait in the wait queue
+			 * for too long.
+			 */
+			if (has_handoff || (!rt_task(waiter->task) &&
+					    !time_after(jiffies, waiter->timeout)))
+				return false;
+
+			new |= RWSEM_FLAG_HANDOFF;
+		} else {
+			new |= RWSEM_WRITER_LOCKED;
+			new &= ~RWSEM_FLAG_HANDOFF;
+
+			if (list_is_singular(&sem->wait_list))
+				new &= ~RWSEM_FLAG_WAITERS;
+		}
+	} while (!atomic_long_try_cmpxchg_acquire(&sem->count, &count, new));
+
+	/*
+	 * We have either acquired the lock with handoff bit cleared or set
+	 * the handoff bit. Only the first waiter can have its handoff_set
+	 * set here to enable optimistic spinning in slowpath loop.
+	 */
+	if (new & RWSEM_FLAG_HANDOFF) {
+		first->handoff_set = true;
+		lockevent_inc(rwsem_wlock_handoff);
+		return false;
+	}
+
+	/*
+	 * Have rwsem_try_write_lock() fully imply rwsem_del_waiter() on
+	 * success.
+	 */
+	list_del(&waiter->list);
+	rwsem_set_owner(sem);
+	return true;
+}
+
+/*
+ * The rwsem_spin_on_owner() function returns the following 4 values
+ * depending on the lock owner state.
+ *   OWNER_NULL  : owner is currently NULL
+ *   OWNER_WRITER: when owner changes and is a writer
+ *   OWNER_READER: when owner changes and the new owner may be a reader.
+ *   OWNER_NONSPINNABLE:
+ *		   when optimistic spinning has to stop because either the
+ *		   owner stops running, is unknown, or its timeslice has
+ *		   been used up.
+ */
+enum owner_state {
+	OWNER_NULL		= 1 << 0,
+	OWNER_WRITER		= 1 << 1,
+	OWNER_READER		= 1 << 2,
+	OWNER_NONSPINNABLE	= 1 << 3,
+};
+
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
+/*
+ * Try to acquire write lock before the writer has been put on wait queue.
+ */
+static inline bool rwsem_try_write_lock_unqueued(struct rw_semaphore *sem)
+{
+	long count = atomic_long_read(&sem->count);
+
+	while (!(count & (RWSEM_LOCK_MASK|RWSEM_FLAG_HANDOFF))) {
+		if (atomic_long_try_cmpxchg_acquire(&sem->count, &count,
+					count | RWSEM_WRITER_LOCKED)) {
+			rwsem_set_owner(sem);
+			lockevent_inc(rwsem_opt_lock);
+			return true;
+		}
+	}
+	return false;
+}
+
+static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
+{
+	struct task_struct *owner;
+	unsigned long flags;
+	bool ret = true;
+
+	if (need_resched()) {
+		lockevent_inc(rwsem_opt_fail);
+		return false;
+	}
+
+	preempt_disable();
+	/*
+	 * Disable preemption is equal to the RCU read-side crital section,
+	 * thus the task_strcut structure won't go away.
+	 */
+	owner = rwsem_owner_flags(sem, &flags);
+	/*
+	 * Don't check the read-owner as the entry may be stale.
+	 */
+	if ((flags & RWSEM_NONSPINNABLE) ||
+	    (owner && !(flags & RWSEM_READER_OWNED) && !owner_on_cpu(owner)))
+		ret = false;
+	preempt_enable();
+
+	lockevent_cond_inc(rwsem_opt_fail, !ret);
+	return ret;
+}
+
+#define OWNER_SPINNABLE		(OWNER_NULL | OWNER_WRITER | OWNER_READER)
+
+static inline enum owner_state
+rwsem_owner_state(struct task_struct *owner, unsigned long flags)
+{
+	if (flags & RWSEM_NONSPINNABLE)
+		return OWNER_NONSPINNABLE;
+
+	if (flags & RWSEM_READER_OWNED)
+		return OWNER_READER;
+
+	return owner ? OWNER_WRITER : OWNER_NULL;
+}
+
+static noinline enum owner_state
+rwsem_spin_on_owner(struct rw_semaphore *sem)
+{
+	struct task_struct *new, *owner;
+	unsigned long flags, new_flags;
+	enum owner_state state;
+
+	lockdep_assert_preemption_disabled();
+
+	owner = rwsem_owner_flags(sem, &flags);
+	state = rwsem_owner_state(owner, flags);
+	if (state != OWNER_WRITER)
+		return state;
+
+	for (;;) {
+		/*
+		 * When a waiting writer set the handoff flag, it may spin
+		 * on the owner as well. Once that writer acquires the lock,
+		 * we can spin on it. So we don't need to quit even when the
+		 * handoff bit is set.
+		 */
+		new = rwsem_owner_flags(sem, &new_flags);
+		if ((new != owner) || (new_flags != flags)) {
+			state = rwsem_owner_state(new, new_flags);
+			break;
+		}
+
+		/*
+		 * Ensure we emit the owner->on_cpu, dereference _after_
+		 * checking sem->owner still matches owner, if that fails,
+		 * owner might point to free()d memory, if it still matches,
+		 * our spinning context already disabled preemption which is
+		 * equal to RCU read-side crital section ensures the memory
+		 * stays valid.
+		 */
+		barrier();
+
+		if (need_resched() || !owner_on_cpu(owner)) {
+			state = OWNER_NONSPINNABLE;
+			break;
+		}
+
+		cpu_relax();
+	}
+
+	return state;
+}
+
+/*
+ * Calculate reader-owned rwsem spinning threshold for writer
+ *
+ * The more readers own the rwsem, the longer it will take for them to
+ * wind down and free the rwsem. So the empirical formula used to
+ * determine the actual spinning time limit here is:
+ *
+ *   Spinning threshold = (10 + nr_readers/2)us
+ *
+ * The limit is capped to a maximum of 25us (30 readers). This is just
+ * a heuristic and is subjected to change in the future.
+ */
+static inline u64 rwsem_rspin_threshold(struct rw_semaphore *sem)
+{
+	long count = atomic_long_read(&sem->count);
+	int readers = count >> RWSEM_READER_SHIFT;
+	u64 delta;
+
+	if (readers > 30)
+		readers = 30;
+	delta = (20 + readers) * NSEC_PER_USEC / 2;
+
+	return sched_clock() + delta;
+}
+
+static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
+{
+	bool taken = false;
+	int prev_owner_state = OWNER_NULL;
+	int loop = 0;
+	u64 rspin_threshold = 0;
+
+	preempt_disable();
+
+	/* sem->wait_lock should not be held when doing optimistic spinning */
+	if (!osq_lock(&sem->osq))
+		goto done;
+
+	/*
+	 * Optimistically spin on the owner field and attempt to acquire the
+	 * lock whenever the owner changes. Spinning will be stopped when:
+	 *  1) the owning writer isn't running; or
+	 *  2) readers own the lock and spinning time has exceeded limit.
+	 */
+	for (;;) {
+		enum owner_state owner_state;
+
+		owner_state = rwsem_spin_on_owner(sem);
+		if (!(owner_state & OWNER_SPINNABLE))
+			break;
+
+		/*
+		 * Try to acquire the lock
+		 */
+		taken = rwsem_try_write_lock_unqueued(sem);
+
+		if (taken)
+			break;
+
+		/*
+		 * Time-based reader-owned rwsem optimistic spinning
+		 */
+		if (owner_state == OWNER_READER) {
+			/*
+			 * Re-initialize rspin_threshold every time when
+			 * the owner state changes from non-reader to reader.
+			 * This allows a writer to steal the lock in between
+			 * 2 reader phases and have the threshold reset at
+			 * the beginning of the 2nd reader phase.
+			 */
+			if (prev_owner_state != OWNER_READER) {
+				if (rwsem_test_oflags(sem, RWSEM_NONSPINNABLE))
+					break;
+				rspin_threshold = rwsem_rspin_threshold(sem);
+				loop = 0;
+			}
+
+			/*
+			 * Check time threshold once every 16 iterations to
+			 * avoid calling sched_clock() too frequently so
+			 * as to reduce the average latency between the times
+			 * when the lock becomes free and when the spinner
+			 * is ready to do a trylock.
+			 */
+			else if (!(++loop & 0xf) && (sched_clock() > rspin_threshold)) {
+				rwsem_set_nonspinnable(sem);
+				lockevent_inc(rwsem_opt_nospin);
+				break;
+			}
+		}
+
+		/*
+		 * An RT task cannot do optimistic spinning if it cannot
+		 * be sure the lock holder is running or live-lock may
+		 * happen if the current task and the lock holder happen
+		 * to run in the same CPU. However, aborting optimistic
+		 * spinning while a NULL owner is detected may miss some
+		 * opportunity where spinning can continue without causing
+		 * problem.
+		 *
+		 * There are 2 possible cases where an RT task may be able
+		 * to continue spinning.
+		 *
+		 * 1) The lock owner is in the process of releasing the
+		 *    lock, sem->owner is cleared but the lock has not
+		 *    been released yet.
+		 * 2) The lock was free and owner cleared, but another
+		 *    task just comes in and acquire the lock before
+		 *    we try to get it. The new owner may be a spinnable
+		 *    writer.
+		 *
+		 * To take advantage of two scenarios listed above, the RT
+		 * task is made to retry one more time to see if it can
+		 * acquire the lock or continue spinning on the new owning
+		 * writer. Of course, if the time lag is long enough or the
+		 * new owner is not a writer or spinnable, the RT task will
+		 * quit spinning.
+		 *
+		 * If the owner is a writer, the need_resched() check is
+		 * done inside rwsem_spin_on_owner(). If the owner is not
+		 * a writer, need_resched() check needs to be done here.
+		 */
+		if (owner_state != OWNER_WRITER) {
+			if (need_resched())
+				break;
+			if (rt_task(current) &&
+			   (prev_owner_state != OWNER_WRITER))
+				break;
+		}
+		prev_owner_state = owner_state;
+
+		/*
+		 * The cpu_relax() call is a compiler barrier which forces
+		 * everything in this loop to be re-loaded. We don't need
+		 * memory barriers as we'll eventually observe the right
+		 * values at the cost of a few extra spins.
+		 */
+		cpu_relax();
+	}
+	osq_unlock(&sem->osq);
+done:
+	preempt_enable();
+	lockevent_cond_inc(rwsem_opt_fail, !taken);
+	return taken;
+}
+
+/*
+ * Clear the owner's RWSEM_NONSPINNABLE bit if it is set. This should
+ * only be called when the reader count reaches 0.
+ */
+static inline void clear_nonspinnable(struct rw_semaphore *sem)
+{
+	if (unlikely(rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)))
+		atomic_long_andnot(RWSEM_NONSPINNABLE, &sem->owner);
+}
+
+#else
+static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
+{
+	return false;
+}
+
+static inline bool rwsem_optimistic_spin(struct rw_semaphore *sem)
+{
+	return false;
+}
+
+static inline void clear_nonspinnable(struct rw_semaphore *sem) { }
+
+static inline enum owner_state
+rwsem_spin_on_owner(struct rw_semaphore *sem)
+{
+	return OWNER_NONSPINNABLE;
+}
+#endif
+
+/*
+ * Prepare to wake up waiter(s) in the wait queue by putting them into the
+ * given wake_q if the rwsem lock owner isn't a writer. If rwsem is likely
+ * reader-owned, wake up read lock waiters in queue front or wake up any
+ * front waiter otherwise.
+
+ * This is being called from both reader and writer slow paths.
+ */
+static inline void rwsem_cond_wake_waiter(struct rw_semaphore *sem, long count,
+					  struct wake_q_head *wake_q)
+{
+	enum rwsem_wake_type wake_type;
+
+	if (count & RWSEM_WRITER_MASK)
+		return;
+
+	if (count & RWSEM_READER_MASK) {
+		wake_type = RWSEM_WAKE_READERS;
+	} else {
+		wake_type = RWSEM_WAKE_ANY;
+		clear_nonspinnable(sem);
+	}
+	rwsem_mark_wake(sem, wake_type, wake_q);
+}
+
+/*
+ * Wait for the read lock to be granted
+ */
+static struct rw_semaphore __sched *
+rwsem_down_read_slowpath(struct rw_semaphore *sem, long count, unsigned int state)
+{
+	long adjustment = -RWSEM_READER_BIAS;
+	long rcnt = (count >> RWSEM_READER_SHIFT);
+	struct rwsem_waiter waiter;
+	DEFINE_WAKE_Q(wake_q);
+
+	/*
+	 * To prevent a constant stream of readers from starving a sleeping
+	 * waiter, don't attempt optimistic lock stealing if the lock is
+	 * currently owned by readers.
+	 */
+	if ((atomic_long_read(&sem->owner) & RWSEM_READER_OWNED) &&
+	    (rcnt > 1) && !(count & RWSEM_WRITER_LOCKED))
+		goto queue;
+
+	/*
+	 * Reader optimistic lock stealing.
+	 */
+	if (!(count & (RWSEM_WRITER_LOCKED | RWSEM_FLAG_HANDOFF))) {
+		rwsem_set_reader_owned(sem);
+		lockevent_inc(rwsem_rlock_steal);
+
+		/*
+		 * Wake up other readers in the wait queue if it is
+		 * the first reader.
+		 */
+		if ((rcnt == 1) && (count & RWSEM_FLAG_WAITERS)) {
+			raw_spin_lock_irq(&sem->wait_lock);
+			if (!list_empty(&sem->wait_list))
+				rwsem_mark_wake(sem, RWSEM_WAKE_READ_OWNED,
+						&wake_q);
+			raw_spin_unlock_irq(&sem->wait_lock);
+			wake_up_q(&wake_q);
+		}
+		return sem;
+	}
+
+queue:
+	waiter.task = current;
+	waiter.type = RWSEM_WAITING_FOR_READ;
+	waiter.timeout = jiffies + RWSEM_WAIT_TIMEOUT;
+	waiter.handoff_set = false;
+
+	raw_spin_lock_irq(&sem->wait_lock);
+	if (list_empty(&sem->wait_list)) {
+		/*
+		 * In case the wait queue is empty and the lock isn't owned
+		 * by a writer, this reader can exit the slowpath and return
+		 * immediately as its RWSEM_READER_BIAS has already been set
+		 * in the count.
+		 */
+		if (!(atomic_long_read(&sem->count) & RWSEM_WRITER_MASK)) {
+			/* Provide lock ACQUIRE */
+			smp_acquire__after_ctrl_dep();
+			raw_spin_unlock_irq(&sem->wait_lock);
+			rwsem_set_reader_owned(sem);
+			lockevent_inc(rwsem_rlock_fast);
+			return sem;
+		}
+		adjustment += RWSEM_FLAG_WAITERS;
+	}
+	rwsem_add_waiter(sem, &waiter);
+
+	/* we're now waiting on the lock, but no longer actively locking */
+	count = atomic_long_add_return(adjustment, &sem->count);
+
+	rwsem_cond_wake_waiter(sem, count, &wake_q);
+	raw_spin_unlock_irq(&sem->wait_lock);
+
+	if (!wake_q_empty(&wake_q))
+		wake_up_q(&wake_q);
+
+	trace_contention_begin(sem, LCB_F_READ);
+
+	/* wait to be given the lock */
+	for (;;) {
+		set_current_state(state);
+		if (!smp_load_acquire(&waiter.task)) {
+			/* Matches rwsem_mark_wake()'s smp_store_release(). */
+			break;
+		}
+		if (signal_pending_state(state, current)) {
+			raw_spin_lock_irq(&sem->wait_lock);
+			if (waiter.task)
+				goto out_nolock;
+			raw_spin_unlock_irq(&sem->wait_lock);
+			/* Ordered by sem->wait_lock against rwsem_mark_wake(). */
+			break;
+		}
+		schedule_preempt_disabled();
+		lockevent_inc(rwsem_sleep_reader);
+	}
+
+	__set_current_state(TASK_RUNNING);
+	lockevent_inc(rwsem_rlock);
+	trace_contention_end(sem, 0);
+	return sem;
+
+out_nolock:
+	rwsem_del_wake_waiter(sem, &waiter, &wake_q);
+	__set_current_state(TASK_RUNNING);
+	lockevent_inc(rwsem_rlock_fail);
+	trace_contention_end(sem, -EINTR);
+	return ERR_PTR(-EINTR);
+}
+
+/*
+ * Wait until we successfully acquire the write lock
+ */
+static struct rw_semaphore __sched *
+rwsem_down_write_slowpath(struct rw_semaphore *sem, int state)
+{
+	struct rwsem_waiter waiter;
+	DEFINE_WAKE_Q(wake_q);
+
+	/* do optimistic spinning and steal lock if possible */
+	if (rwsem_can_spin_on_owner(sem) && rwsem_optimistic_spin(sem)) {
+		/* rwsem_optimistic_spin() implies ACQUIRE on success */
+		return sem;
+	}
+
+	/*
+	 * Optimistic spinning failed, proceed to the slowpath
+	 * and block until we can acquire the sem.
+	 */
+	waiter.task = current;
+	waiter.type = RWSEM_WAITING_FOR_WRITE;
+	waiter.timeout = jiffies + RWSEM_WAIT_TIMEOUT;
+	waiter.handoff_set = false;
+
+	raw_spin_lock_irq(&sem->wait_lock);
+	rwsem_add_waiter(sem, &waiter);
+
+	/* we're now waiting on the lock */
+	if (rwsem_first_waiter(sem) != &waiter) {
+		rwsem_cond_wake_waiter(sem, atomic_long_read(&sem->count),
+				       &wake_q);
+		if (!wake_q_empty(&wake_q)) {
+			/*
+			 * We want to minimize wait_lock hold time especially
+			 * when a large number of readers are to be woken up.
+			 */
+			raw_spin_unlock_irq(&sem->wait_lock);
+			wake_up_q(&wake_q);
+			raw_spin_lock_irq(&sem->wait_lock);
+		}
+	} else {
+		atomic_long_or(RWSEM_FLAG_WAITERS, &sem->count);
+	}
+
+	/* wait until we successfully acquire the lock */
+	set_current_state(state);
+	trace_contention_begin(sem, LCB_F_WRITE);
+
+	for (;;) {
+		if (rwsem_try_write_lock(sem, &waiter)) {
+			/* rwsem_try_write_lock() implies ACQUIRE on success */
+			break;
+		}
+
+		raw_spin_unlock_irq(&sem->wait_lock);
+
+		if (signal_pending_state(state, current))
+			goto out_nolock;
+
+		/*
+		 * After setting the handoff bit and failing to acquire
+		 * the lock, attempt to spin on owner to accelerate lock
+		 * transfer. If the previous owner is a on-cpu writer and it
+		 * has just released the lock, OWNER_NULL will be returned.
+		 * In this case, we attempt to acquire the lock again
+		 * without sleeping.
+		 */
+		if (waiter.handoff_set) {
+			enum owner_state owner_state;
+
+			preempt_disable();
+			owner_state = rwsem_spin_on_owner(sem);
+			preempt_enable();
+
+			if (owner_state == OWNER_NULL)
+				goto trylock_again;
+		}
+
+		schedule();
+		lockevent_inc(rwsem_sleep_writer);
+		set_current_state(state);
+trylock_again:
+		raw_spin_lock_irq(&sem->wait_lock);
+	}
+	__set_current_state(TASK_RUNNING);
+	raw_spin_unlock_irq(&sem->wait_lock);
+	lockevent_inc(rwsem_wlock);
+	trace_contention_end(sem, 0);
+	return sem;
+
+out_nolock:
+	__set_current_state(TASK_RUNNING);
+	raw_spin_lock_irq(&sem->wait_lock);
+	rwsem_del_wake_waiter(sem, &waiter, &wake_q);
+	lockevent_inc(rwsem_wlock_fail);
+	trace_contention_end(sem, -EINTR);
+	return ERR_PTR(-EINTR);
+}
+
+/*
+ * handle waking up a waiter on the semaphore
+ * - up_read/up_write has decremented the active part of count if we come here
+ */
+static struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
+{
+	unsigned long flags;
+	DEFINE_WAKE_Q(wake_q);
+
+	raw_spin_lock_irqsave(&sem->wait_lock, flags);
+
+	if (!list_empty(&sem->wait_list))
+		rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q);
+
+	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
+	wake_up_q(&wake_q);
+
+	return sem;
+}
+
+/*
+ * downgrade a write lock into a read lock
+ * - caller incremented waiting part of count and discovered it still negative
+ * - just wake up any readers at the front of the queue
+ */
+static struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
+{
+	unsigned long flags;
+	DEFINE_WAKE_Q(wake_q);
+
+	raw_spin_lock_irqsave(&sem->wait_lock, flags);
+
+	if (!list_empty(&sem->wait_list))
+		rwsem_mark_wake(sem, RWSEM_WAKE_READ_OWNED, &wake_q);
+
+	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
+	wake_up_q(&wake_q);
+
+	return sem;
+}
+
+/*
+ * lock for reading
+ */
+static __always_inline int __down_read_common(struct rw_semaphore *sem, int state)
+{
+	int ret = 0;
+	long count;
+
+	preempt_disable();
+	if (!rwsem_read_trylock(sem, &count)) {
+		if (IS_ERR(rwsem_down_read_slowpath(sem, count, state))) {
+			ret = -EINTR;
+			goto out;
+		}
+		DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
+	}
+out:
+	preempt_enable();
+	return ret;
+}
+
+static __always_inline void __down_read(struct rw_semaphore *sem)
+{
+	__down_read_common(sem, TASK_UNINTERRUPTIBLE);
+}
+
+static __always_inline int __down_read_interruptible(struct rw_semaphore *sem)
+{
+	return __down_read_common(sem, TASK_INTERRUPTIBLE);
+}
+
+static __always_inline int __down_read_killable(struct rw_semaphore *sem)
+{
+	return __down_read_common(sem, TASK_KILLABLE);
+}
+
+static inline int __down_read_trylock(struct rw_semaphore *sem)
+{
+	int ret = 0;
+	long tmp;
+
+	DEBUG_RWSEMS_WARN_ON(sem->magic != sem, sem);
+
+	preempt_disable();
+	tmp = atomic_long_read(&sem->count);
+	while (!(tmp & RWSEM_READ_FAILED_MASK)) {
+		if (atomic_long_try_cmpxchg_acquire(&sem->count, &tmp,
+						    tmp + RWSEM_READER_BIAS)) {
+			rwsem_set_reader_owned(sem);
+			ret = 1;
+			break;
+		}
+	}
+	preempt_enable();
+	return ret;
+}
+
+/*
+ * lock for writing
+ */
+static inline int __down_write_common(struct rw_semaphore *sem, int state)
+{
+	if (unlikely(!rwsem_write_trylock(sem))) {
+		if (IS_ERR(rwsem_down_write_slowpath(sem, state)))
+			return -EINTR;
+	}
+
+	return 0;
+}
+
+static inline void __down_write(struct rw_semaphore *sem)
+{
+	__down_write_common(sem, TASK_UNINTERRUPTIBLE);
+}
+
+static inline int __down_write_killable(struct rw_semaphore *sem)
+{
+	return __down_write_common(sem, TASK_KILLABLE);
+}
+
+static inline int __down_write_trylock(struct rw_semaphore *sem)
+{
+	DEBUG_RWSEMS_WARN_ON(sem->magic != sem, sem);
+	return rwsem_write_trylock(sem);
+}
+
+/*
+ * unlock after reading
+ */
+static inline void __up_read(struct rw_semaphore *sem)
+{
+	long tmp;
+
+	DEBUG_RWSEMS_WARN_ON(sem->magic != sem, sem);
+	DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
+
+	preempt_disable();
+	rwsem_clear_reader_owned(sem);
+	tmp = atomic_long_add_return_release(-RWSEM_READER_BIAS, &sem->count);
+	DEBUG_RWSEMS_WARN_ON(tmp < 0, sem);
+	if (unlikely((tmp & (RWSEM_LOCK_MASK|RWSEM_FLAG_WAITERS)) ==
+		      RWSEM_FLAG_WAITERS)) {
+		clear_nonspinnable(sem);
+		rwsem_wake(sem);
+	}
+	preempt_enable();
+}
+
+/*
+ * unlock after writing
+ */
+static inline void __up_write(struct rw_semaphore *sem)
+{
+	long tmp;
+
+	DEBUG_RWSEMS_WARN_ON(sem->magic != sem, sem);
+	/*
+	 * sem->owner may differ from current if the ownership is transferred
+	 * to an anonymous writer by setting the RWSEM_NONSPINNABLE bits.
+	 */
+	DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) &&
+			    !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE), sem);
+
+	preempt_disable();
+	rwsem_clear_owner(sem);
+	tmp = atomic_long_fetch_add_release(-RWSEM_WRITER_LOCKED, &sem->count);
+	preempt_enable();
+	if (unlikely(tmp & RWSEM_FLAG_WAITERS))
+		rwsem_wake(sem);
+}
+
+/*
+ * downgrade write lock to read lock
+ */
+static inline void __downgrade_write(struct rw_semaphore *sem)
+{
+	long tmp;
+
+	/*
+	 * When downgrading from exclusive to shared ownership,
+	 * anything inside the write-locked region cannot leak
+	 * into the read side. In contrast, anything in the
+	 * read-locked region is ok to be re-ordered into the
+	 * write side. As such, rely on RELEASE semantics.
+	 */
+	DEBUG_RWSEMS_WARN_ON(rwsem_owner(sem) != current, sem);
+	tmp = atomic_long_fetch_add_release(
+		-RWSEM_WRITER_LOCKED+RWSEM_READER_BIAS, &sem->count);
+	rwsem_set_reader_owned(sem);
+	if (tmp & RWSEM_FLAG_WAITERS)
+		rwsem_downgrade_wake(sem);
+}
+
+#else /* !CONFIG_PREEMPT_RT */
+
+#define RT_MUTEX_BUILD_MUTEX
+#include "rtmutex.c"
+
+#define rwbase_set_and_save_current_state(state)	\
+	set_current_state(state)
+
+#define rwbase_restore_current_state()			\
+	__set_current_state(TASK_RUNNING)
+
+#define rwbase_rtmutex_lock_state(rtm, state)		\
+	__rt_mutex_lock(rtm, state)
+
+#define rwbase_rtmutex_slowlock_locked(rtm, state)	\
+	__rt_mutex_slowlock_locked(rtm, NULL, state)
+
+#define rwbase_rtmutex_unlock(rtm)			\
+	__rt_mutex_unlock(rtm)
+
+#define rwbase_rtmutex_trylock(rtm)			\
+	__rt_mutex_trylock(rtm)
+
+#define rwbase_signal_pending_state(state, current)	\
+	signal_pending_state(state, current)
+
+#define rwbase_schedule()				\
+	schedule()
+
+#include "rwbase_rt.c"
+
+void __init_rwsem(struct rw_semaphore *sem, const char *name,
+		  struct lock_class_key *key)
+{
+	init_rwbase_rt(&(sem)->rwbase);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	debug_check_no_locks_freed((void *)sem, sizeof(*sem));
+	lockdep_init_map_wait(&sem->dep_map, name, key, 0, LD_WAIT_SLEEP);
+#endif
+}
+EXPORT_SYMBOL(__init_rwsem);
+
+static inline void __down_read(struct rw_semaphore *sem)
+{
+	rwbase_read_lock(&sem->rwbase, TASK_UNINTERRUPTIBLE);
+}
+
+static inline int __down_read_interruptible(struct rw_semaphore *sem)
+{
+	return rwbase_read_lock(&sem->rwbase, TASK_INTERRUPTIBLE);
+}
+
+static inline int __down_read_killable(struct rw_semaphore *sem)
+{
+	return rwbase_read_lock(&sem->rwbase, TASK_KILLABLE);
+}
+
+static inline int __down_read_trylock(struct rw_semaphore *sem)
+{
+	return rwbase_read_trylock(&sem->rwbase);
+}
+
+static inline void __up_read(struct rw_semaphore *sem)
+{
+	rwbase_read_unlock(&sem->rwbase, TASK_NORMAL);
+}
+
+static inline void __sched __down_write(struct rw_semaphore *sem)
+{
+	rwbase_write_lock(&sem->rwbase, TASK_UNINTERRUPTIBLE);
+}
+
+static inline int __sched __down_write_killable(struct rw_semaphore *sem)
+{
+	return rwbase_write_lock(&sem->rwbase, TASK_KILLABLE);
+}
+
+static inline int __down_write_trylock(struct rw_semaphore *sem)
+{
+	return rwbase_write_trylock(&sem->rwbase);
+}
+
+static inline void __up_write(struct rw_semaphore *sem)
+{
+	rwbase_write_unlock(&sem->rwbase);
+}
+
+static inline void __downgrade_write(struct rw_semaphore *sem)
+{
+	rwbase_write_downgrade(&sem->rwbase);
+}
+
+/* Debug stubs for the common API */
+#define DEBUG_RWSEMS_WARN_ON(c, sem)
+
+static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem,
+					    struct task_struct *owner)
+{
+}
+
+static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
+{
+	int count = atomic_read(&sem->rwbase.readers);
+
+	return count < 0 && count != READER_BIAS;
+}
+
+#endif /* CONFIG_PREEMPT_RT */
+
+/*
+ * lock for reading
+ */
+void __sched down_read(struct rw_semaphore *sem)
+{
+	might_sleep();
+	rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
+
+	LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
+}
+EXPORT_SYMBOL(down_read);
+
+int __sched down_read_interruptible(struct rw_semaphore *sem)
+{
+	might_sleep();
+	rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
+
+	if (LOCK_CONTENDED_RETURN(sem, __down_read_trylock, __down_read_interruptible)) {
+		rwsem_release(&sem->dep_map, _RET_IP_);
+		return -EINTR;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(down_read_interruptible);
+
+int __sched down_read_killable(struct rw_semaphore *sem)
+{
+	might_sleep();
+	rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
+
+	if (LOCK_CONTENDED_RETURN(sem, __down_read_trylock, __down_read_killable)) {
+		rwsem_release(&sem->dep_map, _RET_IP_);
+		return -EINTR;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(down_read_killable);
+
+/*
+ * trylock for reading -- returns 1 if successful, 0 if contention
+ */
+int down_read_trylock(struct rw_semaphore *sem)
+{
+	int ret = __down_read_trylock(sem);
+
+	if (ret == 1)
+		rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
+	return ret;
+}
+EXPORT_SYMBOL(down_read_trylock);
+
+/*
+ * lock for writing
+ */
+void __sched down_write(struct rw_semaphore *sem)
+{
+	might_sleep();
+	rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
+	LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
+}
+EXPORT_SYMBOL(down_write);
+
+/*
+ * lock for writing
+ */
+int __sched down_write_killable(struct rw_semaphore *sem)
+{
+	might_sleep();
+	rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
+
+	if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock,
+				  __down_write_killable)) {
+		rwsem_release(&sem->dep_map, _RET_IP_);
+		return -EINTR;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(down_write_killable);
+
+/*
+ * trylock for writing -- returns 1 if successful, 0 if contention
+ */
+int down_write_trylock(struct rw_semaphore *sem)
+{
+	int ret = __down_write_trylock(sem);
+
+	if (ret == 1)
+		rwsem_acquire(&sem->dep_map, 0, 1, _RET_IP_);
+
+	return ret;
+}
+EXPORT_SYMBOL(down_write_trylock);
+
+/*
+ * release a read lock
+ */
+void up_read(struct rw_semaphore *sem)
+{
+	rwsem_release(&sem->dep_map, _RET_IP_);
+	__up_read(sem);
+}
+EXPORT_SYMBOL(up_read);
+
+/*
+ * release a write lock
+ */
+void up_write(struct rw_semaphore *sem)
+{
+	rwsem_release(&sem->dep_map, _RET_IP_);
+	__up_write(sem);
+}
+EXPORT_SYMBOL(up_write);
+
+/*
+ * downgrade write lock to read lock
+ */
+void downgrade_write(struct rw_semaphore *sem)
+{
+	lock_downgrade(&sem->dep_map, _RET_IP_);
+	__downgrade_write(sem);
+}
+EXPORT_SYMBOL(downgrade_write);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
+void down_read_nested(struct rw_semaphore *sem, int subclass)
+{
+	might_sleep();
+	rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_);
+	LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
+}
+EXPORT_SYMBOL(down_read_nested);
+
+int down_read_killable_nested(struct rw_semaphore *sem, int subclass)
+{
+	might_sleep();
+	rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_);
+
+	if (LOCK_CONTENDED_RETURN(sem, __down_read_trylock, __down_read_killable)) {
+		rwsem_release(&sem->dep_map, _RET_IP_);
+		return -EINTR;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(down_read_killable_nested);
+
+void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest)
+{
+	might_sleep();
+	rwsem_acquire_nest(&sem->dep_map, 0, 0, nest, _RET_IP_);
+	LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
+}
+EXPORT_SYMBOL(_down_write_nest_lock);
+
+void down_read_non_owner(struct rw_semaphore *sem)
+{
+	might_sleep();
+	__down_read(sem);
+	/*
+	 * The owner value for a reader-owned lock is mostly for debugging
+	 * purpose only and is not critical to the correct functioning of
+	 * rwsem. So it is perfectly fine to set it in a preempt-enabled
+	 * context here.
+	 */
+	__rwsem_set_reader_owned(sem, NULL);
+}
+EXPORT_SYMBOL(down_read_non_owner);
+
+void down_write_nested(struct rw_semaphore *sem, int subclass)
+{
+	might_sleep();
+	rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);
+	LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
+}
+EXPORT_SYMBOL(down_write_nested);
+
+int __sched down_write_killable_nested(struct rw_semaphore *sem, int subclass)
+{
+	might_sleep();
+	rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);
+
+	if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock,
+				  __down_write_killable)) {
+		rwsem_release(&sem->dep_map, _RET_IP_);
+		return -EINTR;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(down_write_killable_nested);
+
+void up_read_non_owner(struct rw_semaphore *sem)
+{
+	DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
+	__up_read(sem);
+}
+EXPORT_SYMBOL(up_read_non_owner);
+
+#endif
diff --git a/kernel/locking/semaphore.c b/kernel/locking/semaphore.c
new file mode 100644
index 000000000..34bfae72f
--- /dev/null
+++ b/kernel/locking/semaphore.c
@@ -0,0 +1,279 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2008 Intel Corporation
+ * Author: Matthew Wilcox <willy@linux.intel.com>
+ *
+ * This file implements counting semaphores.
+ * A counting semaphore may be acquired 'n' times before sleeping.
+ * See mutex.c for single-acquisition sleeping locks which enforce
+ * rules which allow code to be debugged more easily.
+ */
+
+/*
+ * Some notes on the implementation:
+ *
+ * The spinlock controls access to the other members of the semaphore.
+ * down_trylock() and up() can be called from interrupt context, so we
+ * have to disable interrupts when taking the lock.  It turns out various
+ * parts of the kernel expect to be able to use down() on a semaphore in
+ * interrupt context when they know it will succeed, so we have to use
+ * irqsave variants for down(), down_interruptible() and down_killable()
+ * too.
+ *
+ * The ->count variable represents how many more tasks can acquire this
+ * semaphore.  If it's zero, there may be tasks waiting on the wait_list.
+ */
+
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/semaphore.h>
+#include <linux/spinlock.h>
+#include <linux/ftrace.h>
+#include <trace/events/lock.h>
+
+static noinline void __down(struct semaphore *sem);
+static noinline int __down_interruptible(struct semaphore *sem);
+static noinline int __down_killable(struct semaphore *sem);
+static noinline int __down_timeout(struct semaphore *sem, long timeout);
+static noinline void __up(struct semaphore *sem);
+
+/**
+ * down - acquire the semaphore
+ * @sem: the semaphore to be acquired
+ *
+ * Acquires the semaphore.  If no more tasks are allowed to acquire the
+ * semaphore, calling this function will put the task to sleep until the
+ * semaphore is released.
+ *
+ * Use of this function is deprecated, please use down_interruptible() or
+ * down_killable() instead.
+ */
+void __sched down(struct semaphore *sem)
+{
+	unsigned long flags;
+
+	might_sleep();
+	raw_spin_lock_irqsave(&sem->lock, flags);
+	if (likely(sem->count > 0))
+		sem->count--;
+	else
+		__down(sem);
+	raw_spin_unlock_irqrestore(&sem->lock, flags);
+}
+EXPORT_SYMBOL(down);
+
+/**
+ * down_interruptible - acquire the semaphore unless interrupted
+ * @sem: the semaphore to be acquired
+ *
+ * Attempts to acquire the semaphore.  If no more tasks are allowed to
+ * acquire the semaphore, calling this function will put the task to sleep.
+ * If the sleep is interrupted by a signal, this function will return -EINTR.
+ * If the semaphore is successfully acquired, this function returns 0.
+ */
+int __sched down_interruptible(struct semaphore *sem)
+{
+	unsigned long flags;
+	int result = 0;
+
+	might_sleep();
+	raw_spin_lock_irqsave(&sem->lock, flags);
+	if (likely(sem->count > 0))
+		sem->count--;
+	else
+		result = __down_interruptible(sem);
+	raw_spin_unlock_irqrestore(&sem->lock, flags);
+
+	return result;
+}
+EXPORT_SYMBOL(down_interruptible);
+
+/**
+ * down_killable - acquire the semaphore unless killed
+ * @sem: the semaphore to be acquired
+ *
+ * Attempts to acquire the semaphore.  If no more tasks are allowed to
+ * acquire the semaphore, calling this function will put the task to sleep.
+ * If the sleep is interrupted by a fatal signal, this function will return
+ * -EINTR.  If the semaphore is successfully acquired, this function returns
+ * 0.
+ */
+int __sched down_killable(struct semaphore *sem)
+{
+	unsigned long flags;
+	int result = 0;
+
+	might_sleep();
+	raw_spin_lock_irqsave(&sem->lock, flags);
+	if (likely(sem->count > 0))
+		sem->count--;
+	else
+		result = __down_killable(sem);
+	raw_spin_unlock_irqrestore(&sem->lock, flags);
+
+	return result;
+}
+EXPORT_SYMBOL(down_killable);
+
+/**
+ * down_trylock - try to acquire the semaphore, without waiting
+ * @sem: the semaphore to be acquired
+ *
+ * Try to acquire the semaphore atomically.  Returns 0 if the semaphore has
+ * been acquired successfully or 1 if it cannot be acquired.
+ *
+ * NOTE: This return value is inverted from both spin_trylock and
+ * mutex_trylock!  Be careful about this when converting code.
+ *
+ * Unlike mutex_trylock, this function can be used from interrupt context,
+ * and the semaphore can be released by any task or interrupt.
+ */
+int __sched down_trylock(struct semaphore *sem)
+{
+	unsigned long flags;
+	int count;
+
+	raw_spin_lock_irqsave(&sem->lock, flags);
+	count = sem->count - 1;
+	if (likely(count >= 0))
+		sem->count = count;
+	raw_spin_unlock_irqrestore(&sem->lock, flags);
+
+	return (count < 0);
+}
+EXPORT_SYMBOL(down_trylock);
+
+/**
+ * down_timeout - acquire the semaphore within a specified time
+ * @sem: the semaphore to be acquired
+ * @timeout: how long to wait before failing
+ *
+ * Attempts to acquire the semaphore.  If no more tasks are allowed to
+ * acquire the semaphore, calling this function will put the task to sleep.
+ * If the semaphore is not released within the specified number of jiffies,
+ * this function returns -ETIME.  It returns 0 if the semaphore was acquired.
+ */
+int __sched down_timeout(struct semaphore *sem, long timeout)
+{
+	unsigned long flags;
+	int result = 0;
+
+	might_sleep();
+	raw_spin_lock_irqsave(&sem->lock, flags);
+	if (likely(sem->count > 0))
+		sem->count--;
+	else
+		result = __down_timeout(sem, timeout);
+	raw_spin_unlock_irqrestore(&sem->lock, flags);
+
+	return result;
+}
+EXPORT_SYMBOL(down_timeout);
+
+/**
+ * up - release the semaphore
+ * @sem: the semaphore to release
+ *
+ * Release the semaphore.  Unlike mutexes, up() may be called from any
+ * context and even by tasks which have never called down().
+ */
+void __sched up(struct semaphore *sem)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&sem->lock, flags);
+	if (likely(list_empty(&sem->wait_list)))
+		sem->count++;
+	else
+		__up(sem);
+	raw_spin_unlock_irqrestore(&sem->lock, flags);
+}
+EXPORT_SYMBOL(up);
+
+/* Functions for the contended case */
+
+struct semaphore_waiter {
+	struct list_head list;
+	struct task_struct *task;
+	bool up;
+};
+
+/*
+ * Because this function is inlined, the 'state' parameter will be
+ * constant, and thus optimised away by the compiler.  Likewise the
+ * 'timeout' parameter for the cases without timeouts.
+ */
+static inline int __sched ___down_common(struct semaphore *sem, long state,
+								long timeout)
+{
+	struct semaphore_waiter waiter;
+
+	list_add_tail(&waiter.list, &sem->wait_list);
+	waiter.task = current;
+	waiter.up = false;
+
+	for (;;) {
+		if (signal_pending_state(state, current))
+			goto interrupted;
+		if (unlikely(timeout <= 0))
+			goto timed_out;
+		__set_current_state(state);
+		raw_spin_unlock_irq(&sem->lock);
+		timeout = schedule_timeout(timeout);
+		raw_spin_lock_irq(&sem->lock);
+		if (waiter.up)
+			return 0;
+	}
+
+ timed_out:
+	list_del(&waiter.list);
+	return -ETIME;
+
+ interrupted:
+	list_del(&waiter.list);
+	return -EINTR;
+}
+
+static inline int __sched __down_common(struct semaphore *sem, long state,
+					long timeout)
+{
+	int ret;
+
+	trace_contention_begin(sem, 0);
+	ret = ___down_common(sem, state, timeout);
+	trace_contention_end(sem, ret);
+
+	return ret;
+}
+
+static noinline void __sched __down(struct semaphore *sem)
+{
+	__down_common(sem, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
+}
+
+static noinline int __sched __down_interruptible(struct semaphore *sem)
+{
+	return __down_common(sem, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
+}
+
+static noinline int __sched __down_killable(struct semaphore *sem)
+{
+	return __down_common(sem, TASK_KILLABLE, MAX_SCHEDULE_TIMEOUT);
+}
+
+static noinline int __sched __down_timeout(struct semaphore *sem, long timeout)
+{
+	return __down_common(sem, TASK_UNINTERRUPTIBLE, timeout);
+}
+
+static noinline void __sched __up(struct semaphore *sem)
+{
+	struct semaphore_waiter *waiter = list_first_entry(&sem->wait_list,
+						struct semaphore_waiter, list);
+	list_del(&waiter->list);
+	waiter->up = true;
+	wake_up_process(waiter->task);
+}
diff --git a/kernel/locking/spinlock.c b/kernel/locking/spinlock.c
new file mode 100644
index 000000000..8475a0794
--- /dev/null
+++ b/kernel/locking/spinlock.c
@@ -0,0 +1,415 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (2004) Linus Torvalds
+ *
+ * Author: Zwane Mwaikambo <zwane@fsmlabs.com>
+ *
+ * Copyright (2004, 2005) Ingo Molnar
+ *
+ * This file contains the spinlock/rwlock implementations for the
+ * SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
+ *
+ * Note that some architectures have special knowledge about the
+ * stack frames of these functions in their profile_pc. If you
+ * change anything significant here that could change the stack
+ * frame contact the architecture maintainers.
+ */
+
+#include <linux/linkage.h>
+#include <linux/preempt.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/debug_locks.h>
+#include <linux/export.h>
+
+#ifdef CONFIG_MMIOWB
+#ifndef arch_mmiowb_state
+DEFINE_PER_CPU(struct mmiowb_state, __mmiowb_state);
+EXPORT_PER_CPU_SYMBOL(__mmiowb_state);
+#endif
+#endif
+
+/*
+ * If lockdep is enabled then we use the non-preemption spin-ops
+ * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
+ * not re-enabled during lock-acquire (which the preempt-spin-ops do):
+ */
+#if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
+/*
+ * The __lock_function inlines are taken from
+ * spinlock : include/linux/spinlock_api_smp.h
+ * rwlock   : include/linux/rwlock_api_smp.h
+ */
+#else
+
+/*
+ * Some architectures can relax in favour of the CPU owning the lock.
+ */
+#ifndef arch_read_relax
+# define arch_read_relax(l)	cpu_relax()
+#endif
+#ifndef arch_write_relax
+# define arch_write_relax(l)	cpu_relax()
+#endif
+#ifndef arch_spin_relax
+# define arch_spin_relax(l)	cpu_relax()
+#endif
+
+/*
+ * We build the __lock_function inlines here. They are too large for
+ * inlining all over the place, but here is only one user per function
+ * which embeds them into the calling _lock_function below.
+ *
+ * This could be a long-held lock. We both prepare to spin for a long
+ * time (making _this_ CPU preemptible if possible), and we also signal
+ * towards that other CPU that it should break the lock ASAP.
+ */
+#define BUILD_LOCK_OPS(op, locktype)					\
+void __lockfunc __raw_##op##_lock(locktype##_t *lock)			\
+{									\
+	for (;;) {							\
+		preempt_disable();					\
+		if (likely(do_raw_##op##_trylock(lock)))		\
+			break;						\
+		preempt_enable();					\
+									\
+		arch_##op##_relax(&lock->raw_lock);			\
+	}								\
+}									\
+									\
+unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock)	\
+{									\
+	unsigned long flags;						\
+									\
+	for (;;) {							\
+		preempt_disable();					\
+		local_irq_save(flags);					\
+		if (likely(do_raw_##op##_trylock(lock)))		\
+			break;						\
+		local_irq_restore(flags);				\
+		preempt_enable();					\
+									\
+		arch_##op##_relax(&lock->raw_lock);			\
+	}								\
+									\
+	return flags;							\
+}									\
+									\
+void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock)		\
+{									\
+	_raw_##op##_lock_irqsave(lock);					\
+}									\
+									\
+void __lockfunc __raw_##op##_lock_bh(locktype##_t *lock)		\
+{									\
+	unsigned long flags;						\
+									\
+	/*							*/	\
+	/* Careful: we must exclude softirqs too, hence the	*/	\
+	/* irq-disabling. We use the generic preemption-aware	*/	\
+	/* function:						*/	\
+	/**/								\
+	flags = _raw_##op##_lock_irqsave(lock);				\
+	local_bh_disable();						\
+	local_irq_restore(flags);					\
+}									\
+
+/*
+ * Build preemption-friendly versions of the following
+ * lock-spinning functions:
+ *
+ *         __[spin|read|write]_lock()
+ *         __[spin|read|write]_lock_irq()
+ *         __[spin|read|write]_lock_irqsave()
+ *         __[spin|read|write]_lock_bh()
+ */
+BUILD_LOCK_OPS(spin, raw_spinlock);
+
+#ifndef CONFIG_PREEMPT_RT
+BUILD_LOCK_OPS(read, rwlock);
+BUILD_LOCK_OPS(write, rwlock);
+#endif
+
+#endif
+
+#ifndef CONFIG_INLINE_SPIN_TRYLOCK
+noinline int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock)
+{
+	return __raw_spin_trylock(lock);
+}
+EXPORT_SYMBOL(_raw_spin_trylock);
+#endif
+
+#ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH
+noinline int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock)
+{
+	return __raw_spin_trylock_bh(lock);
+}
+EXPORT_SYMBOL(_raw_spin_trylock_bh);
+#endif
+
+#ifndef CONFIG_INLINE_SPIN_LOCK
+noinline void __lockfunc _raw_spin_lock(raw_spinlock_t *lock)
+{
+	__raw_spin_lock(lock);
+}
+EXPORT_SYMBOL(_raw_spin_lock);
+#endif
+
+#ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE
+noinline unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock)
+{
+	return __raw_spin_lock_irqsave(lock);
+}
+EXPORT_SYMBOL(_raw_spin_lock_irqsave);
+#endif
+
+#ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
+noinline void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock)
+{
+	__raw_spin_lock_irq(lock);
+}
+EXPORT_SYMBOL(_raw_spin_lock_irq);
+#endif
+
+#ifndef CONFIG_INLINE_SPIN_LOCK_BH
+noinline void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
+{
+	__raw_spin_lock_bh(lock);
+}
+EXPORT_SYMBOL(_raw_spin_lock_bh);
+#endif
+
+#ifdef CONFIG_UNINLINE_SPIN_UNLOCK
+noinline void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
+{
+	__raw_spin_unlock(lock);
+}
+EXPORT_SYMBOL(_raw_spin_unlock);
+#endif
+
+#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
+noinline void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
+{
+	__raw_spin_unlock_irqrestore(lock, flags);
+}
+EXPORT_SYMBOL(_raw_spin_unlock_irqrestore);
+#endif
+
+#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
+noinline void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
+{
+	__raw_spin_unlock_irq(lock);
+}
+EXPORT_SYMBOL(_raw_spin_unlock_irq);
+#endif
+
+#ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
+noinline void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
+{
+	__raw_spin_unlock_bh(lock);
+}
+EXPORT_SYMBOL(_raw_spin_unlock_bh);
+#endif
+
+#ifndef CONFIG_PREEMPT_RT
+
+#ifndef CONFIG_INLINE_READ_TRYLOCK
+noinline int __lockfunc _raw_read_trylock(rwlock_t *lock)
+{
+	return __raw_read_trylock(lock);
+}
+EXPORT_SYMBOL(_raw_read_trylock);
+#endif
+
+#ifndef CONFIG_INLINE_READ_LOCK
+noinline void __lockfunc _raw_read_lock(rwlock_t *lock)
+{
+	__raw_read_lock(lock);
+}
+EXPORT_SYMBOL(_raw_read_lock);
+#endif
+
+#ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE
+noinline unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock)
+{
+	return __raw_read_lock_irqsave(lock);
+}
+EXPORT_SYMBOL(_raw_read_lock_irqsave);
+#endif
+
+#ifndef CONFIG_INLINE_READ_LOCK_IRQ
+noinline void __lockfunc _raw_read_lock_irq(rwlock_t *lock)
+{
+	__raw_read_lock_irq(lock);
+}
+EXPORT_SYMBOL(_raw_read_lock_irq);
+#endif
+
+#ifndef CONFIG_INLINE_READ_LOCK_BH
+noinline void __lockfunc _raw_read_lock_bh(rwlock_t *lock)
+{
+	__raw_read_lock_bh(lock);
+}
+EXPORT_SYMBOL(_raw_read_lock_bh);
+#endif
+
+#ifndef CONFIG_INLINE_READ_UNLOCK
+noinline void __lockfunc _raw_read_unlock(rwlock_t *lock)
+{
+	__raw_read_unlock(lock);
+}
+EXPORT_SYMBOL(_raw_read_unlock);
+#endif
+
+#ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE
+noinline void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
+{
+	__raw_read_unlock_irqrestore(lock, flags);
+}
+EXPORT_SYMBOL(_raw_read_unlock_irqrestore);
+#endif
+
+#ifndef CONFIG_INLINE_READ_UNLOCK_IRQ
+noinline void __lockfunc _raw_read_unlock_irq(rwlock_t *lock)
+{
+	__raw_read_unlock_irq(lock);
+}
+EXPORT_SYMBOL(_raw_read_unlock_irq);
+#endif
+
+#ifndef CONFIG_INLINE_READ_UNLOCK_BH
+noinline void __lockfunc _raw_read_unlock_bh(rwlock_t *lock)
+{
+	__raw_read_unlock_bh(lock);
+}
+EXPORT_SYMBOL(_raw_read_unlock_bh);
+#endif
+
+#ifndef CONFIG_INLINE_WRITE_TRYLOCK
+noinline int __lockfunc _raw_write_trylock(rwlock_t *lock)
+{
+	return __raw_write_trylock(lock);
+}
+EXPORT_SYMBOL(_raw_write_trylock);
+#endif
+
+#ifndef CONFIG_INLINE_WRITE_LOCK
+noinline void __lockfunc _raw_write_lock(rwlock_t *lock)
+{
+	__raw_write_lock(lock);
+}
+EXPORT_SYMBOL(_raw_write_lock);
+
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
+#define __raw_write_lock_nested(lock, subclass)	__raw_write_lock(((void)(subclass), (lock)))
+#endif
+
+void __lockfunc _raw_write_lock_nested(rwlock_t *lock, int subclass)
+{
+	__raw_write_lock_nested(lock, subclass);
+}
+EXPORT_SYMBOL(_raw_write_lock_nested);
+#endif
+
+#ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
+noinline unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
+{
+	return __raw_write_lock_irqsave(lock);
+}
+EXPORT_SYMBOL(_raw_write_lock_irqsave);
+#endif
+
+#ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
+noinline void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
+{
+	__raw_write_lock_irq(lock);
+}
+EXPORT_SYMBOL(_raw_write_lock_irq);
+#endif
+
+#ifndef CONFIG_INLINE_WRITE_LOCK_BH
+noinline void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
+{
+	__raw_write_lock_bh(lock);
+}
+EXPORT_SYMBOL(_raw_write_lock_bh);
+#endif
+
+#ifndef CONFIG_INLINE_WRITE_UNLOCK
+noinline void __lockfunc _raw_write_unlock(rwlock_t *lock)
+{
+	__raw_write_unlock(lock);
+}
+EXPORT_SYMBOL(_raw_write_unlock);
+#endif
+
+#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
+noinline void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
+{
+	__raw_write_unlock_irqrestore(lock, flags);
+}
+EXPORT_SYMBOL(_raw_write_unlock_irqrestore);
+#endif
+
+#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
+noinline void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
+{
+	__raw_write_unlock_irq(lock);
+}
+EXPORT_SYMBOL(_raw_write_unlock_irq);
+#endif
+
+#ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
+noinline void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
+{
+	__raw_write_unlock_bh(lock);
+}
+EXPORT_SYMBOL(_raw_write_unlock_bh);
+#endif
+
+#endif /* !CONFIG_PREEMPT_RT */
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
+void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
+{
+	preempt_disable();
+	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
+}
+EXPORT_SYMBOL(_raw_spin_lock_nested);
+
+unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock,
+						   int subclass)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	preempt_disable();
+	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
+	return flags;
+}
+EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);
+
+void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock,
+				     struct lockdep_map *nest_lock)
+{
+	preempt_disable();
+	spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
+	LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
+}
+EXPORT_SYMBOL(_raw_spin_lock_nest_lock);
+
+#endif
+
+notrace int in_lock_functions(unsigned long addr)
+{
+	/* Linker adds these: start and end of __lockfunc functions */
+	extern char __lock_text_start[], __lock_text_end[];
+
+	return addr >= (unsigned long)__lock_text_start
+	&& addr < (unsigned long)__lock_text_end;
+}
+EXPORT_SYMBOL(in_lock_functions);
diff --git a/kernel/locking/spinlock_debug.c b/kernel/locking/spinlock_debug.c
new file mode 100644
index 000000000..14235671a
--- /dev/null
+++ b/kernel/locking/spinlock_debug.c
@@ -0,0 +1,235 @@
+/*
+ * Copyright 2005, Red Hat, Inc., Ingo Molnar
+ * Released under the General Public License (GPL).
+ *
+ * This file contains the spinlock/rwlock implementations for
+ * DEBUG_SPINLOCK.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/nmi.h>
+#include <linux/interrupt.h>
+#include <linux/debug_locks.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+
+void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
+			  struct lock_class_key *key, short inner)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held lock:
+	 */
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map_wait(&lock->dep_map, name, key, 0, inner);
+#endif
+	lock->raw_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+	lock->magic = SPINLOCK_MAGIC;
+	lock->owner = SPINLOCK_OWNER_INIT;
+	lock->owner_cpu = -1;
+}
+
+EXPORT_SYMBOL(__raw_spin_lock_init);
+
+#ifndef CONFIG_PREEMPT_RT
+void __rwlock_init(rwlock_t *lock, const char *name,
+		   struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held lock:
+	 */
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_CONFIG);
+#endif
+	lock->raw_lock = (arch_rwlock_t) __ARCH_RW_LOCK_UNLOCKED;
+	lock->magic = RWLOCK_MAGIC;
+	lock->owner = SPINLOCK_OWNER_INIT;
+	lock->owner_cpu = -1;
+}
+
+EXPORT_SYMBOL(__rwlock_init);
+#endif
+
+static void spin_dump(raw_spinlock_t *lock, const char *msg)
+{
+	struct task_struct *owner = READ_ONCE(lock->owner);
+
+	if (owner == SPINLOCK_OWNER_INIT)
+		owner = NULL;
+	printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
+		msg, raw_smp_processor_id(),
+		current->comm, task_pid_nr(current));
+	printk(KERN_EMERG " lock: %pS, .magic: %08x, .owner: %s/%d, "
+			".owner_cpu: %d\n",
+		lock, READ_ONCE(lock->magic),
+		owner ? owner->comm : "<none>",
+		owner ? task_pid_nr(owner) : -1,
+		READ_ONCE(lock->owner_cpu));
+	dump_stack();
+}
+
+static void spin_bug(raw_spinlock_t *lock, const char *msg)
+{
+	if (!debug_locks_off())
+		return;
+
+	spin_dump(lock, msg);
+}
+
+#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
+
+static inline void
+debug_spin_lock_before(raw_spinlock_t *lock)
+{
+	SPIN_BUG_ON(READ_ONCE(lock->magic) != SPINLOCK_MAGIC, lock, "bad magic");
+	SPIN_BUG_ON(READ_ONCE(lock->owner) == current, lock, "recursion");
+	SPIN_BUG_ON(READ_ONCE(lock->owner_cpu) == raw_smp_processor_id(),
+							lock, "cpu recursion");
+}
+
+static inline void debug_spin_lock_after(raw_spinlock_t *lock)
+{
+	WRITE_ONCE(lock->owner_cpu, raw_smp_processor_id());
+	WRITE_ONCE(lock->owner, current);
+}
+
+static inline void debug_spin_unlock(raw_spinlock_t *lock)
+{
+	SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
+	SPIN_BUG_ON(!raw_spin_is_locked(lock), lock, "already unlocked");
+	SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
+	SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
+							lock, "wrong CPU");
+	WRITE_ONCE(lock->owner, SPINLOCK_OWNER_INIT);
+	WRITE_ONCE(lock->owner_cpu, -1);
+}
+
+/*
+ * We are now relying on the NMI watchdog to detect lockup instead of doing
+ * the detection here with an unfair lock which can cause problem of its own.
+ */
+void do_raw_spin_lock(raw_spinlock_t *lock)
+{
+	debug_spin_lock_before(lock);
+	arch_spin_lock(&lock->raw_lock);
+	mmiowb_spin_lock();
+	debug_spin_lock_after(lock);
+}
+
+int do_raw_spin_trylock(raw_spinlock_t *lock)
+{
+	int ret = arch_spin_trylock(&lock->raw_lock);
+
+	if (ret) {
+		mmiowb_spin_lock();
+		debug_spin_lock_after(lock);
+	}
+#ifndef CONFIG_SMP
+	/*
+	 * Must not happen on UP:
+	 */
+	SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
+#endif
+	return ret;
+}
+
+void do_raw_spin_unlock(raw_spinlock_t *lock)
+{
+	mmiowb_spin_unlock();
+	debug_spin_unlock(lock);
+	arch_spin_unlock(&lock->raw_lock);
+}
+
+#ifndef CONFIG_PREEMPT_RT
+static void rwlock_bug(rwlock_t *lock, const char *msg)
+{
+	if (!debug_locks_off())
+		return;
+
+	printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
+		msg, raw_smp_processor_id(), current->comm,
+		task_pid_nr(current), lock);
+	dump_stack();
+}
+
+#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
+
+void do_raw_read_lock(rwlock_t *lock)
+{
+	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
+	arch_read_lock(&lock->raw_lock);
+}
+
+int do_raw_read_trylock(rwlock_t *lock)
+{
+	int ret = arch_read_trylock(&lock->raw_lock);
+
+#ifndef CONFIG_SMP
+	/*
+	 * Must not happen on UP:
+	 */
+	RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
+#endif
+	return ret;
+}
+
+void do_raw_read_unlock(rwlock_t *lock)
+{
+	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
+	arch_read_unlock(&lock->raw_lock);
+}
+
+static inline void debug_write_lock_before(rwlock_t *lock)
+{
+	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
+	RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
+	RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
+							lock, "cpu recursion");
+}
+
+static inline void debug_write_lock_after(rwlock_t *lock)
+{
+	WRITE_ONCE(lock->owner_cpu, raw_smp_processor_id());
+	WRITE_ONCE(lock->owner, current);
+}
+
+static inline void debug_write_unlock(rwlock_t *lock)
+{
+	RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
+	RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
+	RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
+							lock, "wrong CPU");
+	WRITE_ONCE(lock->owner, SPINLOCK_OWNER_INIT);
+	WRITE_ONCE(lock->owner_cpu, -1);
+}
+
+void do_raw_write_lock(rwlock_t *lock)
+{
+	debug_write_lock_before(lock);
+	arch_write_lock(&lock->raw_lock);
+	debug_write_lock_after(lock);
+}
+
+int do_raw_write_trylock(rwlock_t *lock)
+{
+	int ret = arch_write_trylock(&lock->raw_lock);
+
+	if (ret)
+		debug_write_lock_after(lock);
+#ifndef CONFIG_SMP
+	/*
+	 * Must not happen on UP:
+	 */
+	RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
+#endif
+	return ret;
+}
+
+void do_raw_write_unlock(rwlock_t *lock)
+{
+	debug_write_unlock(lock);
+	arch_write_unlock(&lock->raw_lock);
+}
+
+#endif /* !CONFIG_PREEMPT_RT */
diff --git a/kernel/locking/spinlock_rt.c b/kernel/locking/spinlock_rt.c
new file mode 100644
index 000000000..48a19ed84
--- /dev/null
+++ b/kernel/locking/spinlock_rt.c
@@ -0,0 +1,280 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PREEMPT_RT substitution for spin/rw_locks
+ *
+ * spinlocks and rwlocks on RT are based on rtmutexes, with a few twists to
+ * resemble the non RT semantics:
+ *
+ * - Contrary to plain rtmutexes, spinlocks and rwlocks are state
+ *   preserving. The task state is saved before blocking on the underlying
+ *   rtmutex, and restored when the lock has been acquired. Regular wakeups
+ *   during that time are redirected to the saved state so no wake up is
+ *   missed.
+ *
+ * - Non RT spin/rwlocks disable preemption and eventually interrupts.
+ *   Disabling preemption has the side effect of disabling migration and
+ *   preventing RCU grace periods.
+ *
+ *   The RT substitutions explicitly disable migration and take
+ *   rcu_read_lock() across the lock held section.
+ */
+#include <linux/spinlock.h>
+#include <linux/export.h>
+
+#define RT_MUTEX_BUILD_SPINLOCKS
+#include "rtmutex.c"
+
+/*
+ * __might_resched() skips the state check as rtlocks are state
+ * preserving. Take RCU nesting into account as spin/read/write_lock() can
+ * legitimately nest into an RCU read side critical section.
+ */
+#define RTLOCK_RESCHED_OFFSETS						\
+	(rcu_preempt_depth() << MIGHT_RESCHED_RCU_SHIFT)
+
+#define rtlock_might_resched()						\
+	__might_resched(__FILE__, __LINE__, RTLOCK_RESCHED_OFFSETS)
+
+static __always_inline void rtlock_lock(struct rt_mutex_base *rtm)
+{
+	if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current)))
+		rtlock_slowlock(rtm);
+}
+
+static __always_inline void __rt_spin_lock(spinlock_t *lock)
+{
+	rtlock_might_resched();
+	rtlock_lock(&lock->lock);
+	rcu_read_lock();
+	migrate_disable();
+}
+
+void __sched rt_spin_lock(spinlock_t *lock)
+{
+	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	__rt_spin_lock(lock);
+}
+EXPORT_SYMBOL(rt_spin_lock);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __sched rt_spin_lock_nested(spinlock_t *lock, int subclass)
+{
+	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	__rt_spin_lock(lock);
+}
+EXPORT_SYMBOL(rt_spin_lock_nested);
+
+void __sched rt_spin_lock_nest_lock(spinlock_t *lock,
+				    struct lockdep_map *nest_lock)
+{
+	spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
+	__rt_spin_lock(lock);
+}
+EXPORT_SYMBOL(rt_spin_lock_nest_lock);
+#endif
+
+void __sched rt_spin_unlock(spinlock_t *lock)
+{
+	spin_release(&lock->dep_map, _RET_IP_);
+	migrate_enable();
+	rcu_read_unlock();
+
+	if (unlikely(!rt_mutex_cmpxchg_release(&lock->lock, current, NULL)))
+		rt_mutex_slowunlock(&lock->lock);
+}
+EXPORT_SYMBOL(rt_spin_unlock);
+
+/*
+ * Wait for the lock to get unlocked: instead of polling for an unlock
+ * (like raw spinlocks do), lock and unlock, to force the kernel to
+ * schedule if there's contention:
+ */
+void __sched rt_spin_lock_unlock(spinlock_t *lock)
+{
+	spin_lock(lock);
+	spin_unlock(lock);
+}
+EXPORT_SYMBOL(rt_spin_lock_unlock);
+
+static __always_inline int __rt_spin_trylock(spinlock_t *lock)
+{
+	int ret = 1;
+
+	if (unlikely(!rt_mutex_cmpxchg_acquire(&lock->lock, NULL, current)))
+		ret = rt_mutex_slowtrylock(&lock->lock);
+
+	if (ret) {
+		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+		rcu_read_lock();
+		migrate_disable();
+	}
+	return ret;
+}
+
+int __sched rt_spin_trylock(spinlock_t *lock)
+{
+	return __rt_spin_trylock(lock);
+}
+EXPORT_SYMBOL(rt_spin_trylock);
+
+int __sched rt_spin_trylock_bh(spinlock_t *lock)
+{
+	int ret;
+
+	local_bh_disable();
+	ret = __rt_spin_trylock(lock);
+	if (!ret)
+		local_bh_enable();
+	return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock_bh);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __rt_spin_lock_init(spinlock_t *lock, const char *name,
+			 struct lock_class_key *key, bool percpu)
+{
+	u8 type = percpu ? LD_LOCK_PERCPU : LD_LOCK_NORMAL;
+
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map_type(&lock->dep_map, name, key, 0, LD_WAIT_CONFIG,
+			      LD_WAIT_INV, type);
+}
+EXPORT_SYMBOL(__rt_spin_lock_init);
+#endif
+
+/*
+ * RT-specific reader/writer locks
+ */
+#define rwbase_set_and_save_current_state(state)	\
+	current_save_and_set_rtlock_wait_state()
+
+#define rwbase_restore_current_state()			\
+	current_restore_rtlock_saved_state()
+
+static __always_inline int
+rwbase_rtmutex_lock_state(struct rt_mutex_base *rtm, unsigned int state)
+{
+	if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current)))
+		rtlock_slowlock(rtm);
+	return 0;
+}
+
+static __always_inline int
+rwbase_rtmutex_slowlock_locked(struct rt_mutex_base *rtm, unsigned int state)
+{
+	rtlock_slowlock_locked(rtm);
+	return 0;
+}
+
+static __always_inline void rwbase_rtmutex_unlock(struct rt_mutex_base *rtm)
+{
+	if (likely(rt_mutex_cmpxchg_acquire(rtm, current, NULL)))
+		return;
+
+	rt_mutex_slowunlock(rtm);
+}
+
+static __always_inline int  rwbase_rtmutex_trylock(struct rt_mutex_base *rtm)
+{
+	if (likely(rt_mutex_cmpxchg_acquire(rtm, NULL, current)))
+		return 1;
+
+	return rt_mutex_slowtrylock(rtm);
+}
+
+#define rwbase_signal_pending_state(state, current)	(0)
+
+#define rwbase_schedule()				\
+	schedule_rtlock()
+
+#include "rwbase_rt.c"
+/*
+ * The common functions which get wrapped into the rwlock API.
+ */
+int __sched rt_read_trylock(rwlock_t *rwlock)
+{
+	int ret;
+
+	ret = rwbase_read_trylock(&rwlock->rwbase);
+	if (ret) {
+		rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_);
+		rcu_read_lock();
+		migrate_disable();
+	}
+	return ret;
+}
+EXPORT_SYMBOL(rt_read_trylock);
+
+int __sched rt_write_trylock(rwlock_t *rwlock)
+{
+	int ret;
+
+	ret = rwbase_write_trylock(&rwlock->rwbase);
+	if (ret) {
+		rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
+		rcu_read_lock();
+		migrate_disable();
+	}
+	return ret;
+}
+EXPORT_SYMBOL(rt_write_trylock);
+
+void __sched rt_read_lock(rwlock_t *rwlock)
+{
+	rtlock_might_resched();
+	rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_);
+	rwbase_read_lock(&rwlock->rwbase, TASK_RTLOCK_WAIT);
+	rcu_read_lock();
+	migrate_disable();
+}
+EXPORT_SYMBOL(rt_read_lock);
+
+void __sched rt_write_lock(rwlock_t *rwlock)
+{
+	rtlock_might_resched();
+	rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
+	rwbase_write_lock(&rwlock->rwbase, TASK_RTLOCK_WAIT);
+	rcu_read_lock();
+	migrate_disable();
+}
+EXPORT_SYMBOL(rt_write_lock);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __sched rt_write_lock_nested(rwlock_t *rwlock, int subclass)
+{
+	rtlock_might_resched();
+	rwlock_acquire(&rwlock->dep_map, subclass, 0, _RET_IP_);
+	rwbase_write_lock(&rwlock->rwbase, TASK_RTLOCK_WAIT);
+	rcu_read_lock();
+	migrate_disable();
+}
+EXPORT_SYMBOL(rt_write_lock_nested);
+#endif
+
+void __sched rt_read_unlock(rwlock_t *rwlock)
+{
+	rwlock_release(&rwlock->dep_map, _RET_IP_);
+	migrate_enable();
+	rcu_read_unlock();
+	rwbase_read_unlock(&rwlock->rwbase, TASK_RTLOCK_WAIT);
+}
+EXPORT_SYMBOL(rt_read_unlock);
+
+void __sched rt_write_unlock(rwlock_t *rwlock)
+{
+	rwlock_release(&rwlock->dep_map, _RET_IP_);
+	rcu_read_unlock();
+	migrate_enable();
+	rwbase_write_unlock(&rwlock->rwbase);
+}
+EXPORT_SYMBOL(rt_write_unlock);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __rt_rwlock_init(rwlock_t *rwlock, const char *name,
+		      struct lock_class_key *key)
+{
+	debug_check_no_locks_freed((void *)rwlock, sizeof(*rwlock));
+	lockdep_init_map_wait(&rwlock->dep_map, name, key, 0, LD_WAIT_CONFIG);
+}
+EXPORT_SYMBOL(__rt_rwlock_init);
+#endif
diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c
new file mode 100644
index 000000000..b1e256951
--- /dev/null
+++ b/kernel/locking/test-ww_mutex.c
@@ -0,0 +1,683 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module-based API test facility for ww_mutexes
+ */
+
+#include <linux/kernel.h>
+
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/ww_mutex.h>
+
+static DEFINE_WD_CLASS(ww_class);
+struct workqueue_struct *wq;
+
+#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
+#define ww_acquire_init_noinject(a, b) do { \
+		ww_acquire_init((a), (b)); \
+		(a)->deadlock_inject_countdown = ~0U; \
+	} while (0)
+#else
+#define ww_acquire_init_noinject(a, b) ww_acquire_init((a), (b))
+#endif
+
+struct test_mutex {
+	struct work_struct work;
+	struct ww_mutex mutex;
+	struct completion ready, go, done;
+	unsigned int flags;
+};
+
+#define TEST_MTX_SPIN BIT(0)
+#define TEST_MTX_TRY BIT(1)
+#define TEST_MTX_CTX BIT(2)
+#define __TEST_MTX_LAST BIT(3)
+
+static void test_mutex_work(struct work_struct *work)
+{
+	struct test_mutex *mtx = container_of(work, typeof(*mtx), work);
+
+	complete(&mtx->ready);
+	wait_for_completion(&mtx->go);
+
+	if (mtx->flags & TEST_MTX_TRY) {
+		while (!ww_mutex_trylock(&mtx->mutex, NULL))
+			cond_resched();
+	} else {
+		ww_mutex_lock(&mtx->mutex, NULL);
+	}
+	complete(&mtx->done);
+	ww_mutex_unlock(&mtx->mutex);
+}
+
+static int __test_mutex(unsigned int flags)
+{
+#define TIMEOUT (HZ / 16)
+	struct test_mutex mtx;
+	struct ww_acquire_ctx ctx;
+	int ret;
+
+	ww_mutex_init(&mtx.mutex, &ww_class);
+	ww_acquire_init(&ctx, &ww_class);
+
+	INIT_WORK_ONSTACK(&mtx.work, test_mutex_work);
+	init_completion(&mtx.ready);
+	init_completion(&mtx.go);
+	init_completion(&mtx.done);
+	mtx.flags = flags;
+
+	schedule_work(&mtx.work);
+
+	wait_for_completion(&mtx.ready);
+	ww_mutex_lock(&mtx.mutex, (flags & TEST_MTX_CTX) ? &ctx : NULL);
+	complete(&mtx.go);
+	if (flags & TEST_MTX_SPIN) {
+		unsigned long timeout = jiffies + TIMEOUT;
+
+		ret = 0;
+		do {
+			if (completion_done(&mtx.done)) {
+				ret = -EINVAL;
+				break;
+			}
+			cond_resched();
+		} while (time_before(jiffies, timeout));
+	} else {
+		ret = wait_for_completion_timeout(&mtx.done, TIMEOUT);
+	}
+	ww_mutex_unlock(&mtx.mutex);
+	ww_acquire_fini(&ctx);
+
+	if (ret) {
+		pr_err("%s(flags=%x): mutual exclusion failure\n",
+		       __func__, flags);
+		ret = -EINVAL;
+	}
+
+	flush_work(&mtx.work);
+	destroy_work_on_stack(&mtx.work);
+	return ret;
+#undef TIMEOUT
+}
+
+static int test_mutex(void)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < __TEST_MTX_LAST; i++) {
+		ret = __test_mutex(i);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int test_aa(bool trylock)
+{
+	struct ww_mutex mutex;
+	struct ww_acquire_ctx ctx;
+	int ret;
+	const char *from = trylock ? "trylock" : "lock";
+
+	ww_mutex_init(&mutex, &ww_class);
+	ww_acquire_init(&ctx, &ww_class);
+
+	if (!trylock) {
+		ret = ww_mutex_lock(&mutex, &ctx);
+		if (ret) {
+			pr_err("%s: initial lock failed!\n", __func__);
+			goto out;
+		}
+	} else {
+		ret = !ww_mutex_trylock(&mutex, &ctx);
+		if (ret) {
+			pr_err("%s: initial trylock failed!\n", __func__);
+			goto out;
+		}
+	}
+
+	if (ww_mutex_trylock(&mutex, NULL))  {
+		pr_err("%s: trylocked itself without context from %s!\n", __func__, from);
+		ww_mutex_unlock(&mutex);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (ww_mutex_trylock(&mutex, &ctx))  {
+		pr_err("%s: trylocked itself with context from %s!\n", __func__, from);
+		ww_mutex_unlock(&mutex);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = ww_mutex_lock(&mutex, &ctx);
+	if (ret != -EALREADY) {
+		pr_err("%s: missed deadlock for recursing, ret=%d from %s\n",
+		       __func__, ret, from);
+		if (!ret)
+			ww_mutex_unlock(&mutex);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ww_mutex_unlock(&mutex);
+	ret = 0;
+out:
+	ww_acquire_fini(&ctx);
+	return ret;
+}
+
+struct test_abba {
+	struct work_struct work;
+	struct ww_mutex a_mutex;
+	struct ww_mutex b_mutex;
+	struct completion a_ready;
+	struct completion b_ready;
+	bool resolve, trylock;
+	int result;
+};
+
+static void test_abba_work(struct work_struct *work)
+{
+	struct test_abba *abba = container_of(work, typeof(*abba), work);
+	struct ww_acquire_ctx ctx;
+	int err;
+
+	ww_acquire_init_noinject(&ctx, &ww_class);
+	if (!abba->trylock)
+		ww_mutex_lock(&abba->b_mutex, &ctx);
+	else
+		WARN_ON(!ww_mutex_trylock(&abba->b_mutex, &ctx));
+
+	WARN_ON(READ_ONCE(abba->b_mutex.ctx) != &ctx);
+
+	complete(&abba->b_ready);
+	wait_for_completion(&abba->a_ready);
+
+	err = ww_mutex_lock(&abba->a_mutex, &ctx);
+	if (abba->resolve && err == -EDEADLK) {
+		ww_mutex_unlock(&abba->b_mutex);
+		ww_mutex_lock_slow(&abba->a_mutex, &ctx);
+		err = ww_mutex_lock(&abba->b_mutex, &ctx);
+	}
+
+	if (!err)
+		ww_mutex_unlock(&abba->a_mutex);
+	ww_mutex_unlock(&abba->b_mutex);
+	ww_acquire_fini(&ctx);
+
+	abba->result = err;
+}
+
+static int test_abba(bool trylock, bool resolve)
+{
+	struct test_abba abba;
+	struct ww_acquire_ctx ctx;
+	int err, ret;
+
+	ww_mutex_init(&abba.a_mutex, &ww_class);
+	ww_mutex_init(&abba.b_mutex, &ww_class);
+	INIT_WORK_ONSTACK(&abba.work, test_abba_work);
+	init_completion(&abba.a_ready);
+	init_completion(&abba.b_ready);
+	abba.trylock = trylock;
+	abba.resolve = resolve;
+
+	schedule_work(&abba.work);
+
+	ww_acquire_init_noinject(&ctx, &ww_class);
+	if (!trylock)
+		ww_mutex_lock(&abba.a_mutex, &ctx);
+	else
+		WARN_ON(!ww_mutex_trylock(&abba.a_mutex, &ctx));
+
+	WARN_ON(READ_ONCE(abba.a_mutex.ctx) != &ctx);
+
+	complete(&abba.a_ready);
+	wait_for_completion(&abba.b_ready);
+
+	err = ww_mutex_lock(&abba.b_mutex, &ctx);
+	if (resolve && err == -EDEADLK) {
+		ww_mutex_unlock(&abba.a_mutex);
+		ww_mutex_lock_slow(&abba.b_mutex, &ctx);
+		err = ww_mutex_lock(&abba.a_mutex, &ctx);
+	}
+
+	if (!err)
+		ww_mutex_unlock(&abba.b_mutex);
+	ww_mutex_unlock(&abba.a_mutex);
+	ww_acquire_fini(&ctx);
+
+	flush_work(&abba.work);
+	destroy_work_on_stack(&abba.work);
+
+	ret = 0;
+	if (resolve) {
+		if (err || abba.result) {
+			pr_err("%s: failed to resolve ABBA deadlock, A err=%d, B err=%d\n",
+			       __func__, err, abba.result);
+			ret = -EINVAL;
+		}
+	} else {
+		if (err != -EDEADLK && abba.result != -EDEADLK) {
+			pr_err("%s: missed ABBA deadlock, A err=%d, B err=%d\n",
+			       __func__, err, abba.result);
+			ret = -EINVAL;
+		}
+	}
+	return ret;
+}
+
+struct test_cycle {
+	struct work_struct work;
+	struct ww_mutex a_mutex;
+	struct ww_mutex *b_mutex;
+	struct completion *a_signal;
+	struct completion b_signal;
+	int result;
+};
+
+static void test_cycle_work(struct work_struct *work)
+{
+	struct test_cycle *cycle = container_of(work, typeof(*cycle), work);
+	struct ww_acquire_ctx ctx;
+	int err, erra = 0;
+
+	ww_acquire_init_noinject(&ctx, &ww_class);
+	ww_mutex_lock(&cycle->a_mutex, &ctx);
+
+	complete(cycle->a_signal);
+	wait_for_completion(&cycle->b_signal);
+
+	err = ww_mutex_lock(cycle->b_mutex, &ctx);
+	if (err == -EDEADLK) {
+		err = 0;
+		ww_mutex_unlock(&cycle->a_mutex);
+		ww_mutex_lock_slow(cycle->b_mutex, &ctx);
+		erra = ww_mutex_lock(&cycle->a_mutex, &ctx);
+	}
+
+	if (!err)
+		ww_mutex_unlock(cycle->b_mutex);
+	if (!erra)
+		ww_mutex_unlock(&cycle->a_mutex);
+	ww_acquire_fini(&ctx);
+
+	cycle->result = err ?: erra;
+}
+
+static int __test_cycle(unsigned int nthreads)
+{
+	struct test_cycle *cycles;
+	unsigned int n, last = nthreads - 1;
+	int ret;
+
+	cycles = kmalloc_array(nthreads, sizeof(*cycles), GFP_KERNEL);
+	if (!cycles)
+		return -ENOMEM;
+
+	for (n = 0; n < nthreads; n++) {
+		struct test_cycle *cycle = &cycles[n];
+
+		ww_mutex_init(&cycle->a_mutex, &ww_class);
+		if (n == last)
+			cycle->b_mutex = &cycles[0].a_mutex;
+		else
+			cycle->b_mutex = &cycles[n + 1].a_mutex;
+
+		if (n == 0)
+			cycle->a_signal = &cycles[last].b_signal;
+		else
+			cycle->a_signal = &cycles[n - 1].b_signal;
+		init_completion(&cycle->b_signal);
+
+		INIT_WORK(&cycle->work, test_cycle_work);
+		cycle->result = 0;
+	}
+
+	for (n = 0; n < nthreads; n++)
+		queue_work(wq, &cycles[n].work);
+
+	flush_workqueue(wq);
+
+	ret = 0;
+	for (n = 0; n < nthreads; n++) {
+		struct test_cycle *cycle = &cycles[n];
+
+		if (!cycle->result)
+			continue;
+
+		pr_err("cyclic deadlock not resolved, ret[%d/%d] = %d\n",
+		       n, nthreads, cycle->result);
+		ret = -EINVAL;
+		break;
+	}
+
+	for (n = 0; n < nthreads; n++)
+		ww_mutex_destroy(&cycles[n].a_mutex);
+	kfree(cycles);
+	return ret;
+}
+
+static int test_cycle(unsigned int ncpus)
+{
+	unsigned int n;
+	int ret;
+
+	for (n = 2; n <= ncpus + 1; n++) {
+		ret = __test_cycle(n);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+struct stress {
+	struct work_struct work;
+	struct ww_mutex *locks;
+	unsigned long timeout;
+	int nlocks;
+};
+
+static int *get_random_order(int count)
+{
+	int *order;
+	int n, r, tmp;
+
+	order = kmalloc_array(count, sizeof(*order), GFP_KERNEL);
+	if (!order)
+		return order;
+
+	for (n = 0; n < count; n++)
+		order[n] = n;
+
+	for (n = count - 1; n > 1; n--) {
+		r = prandom_u32_max(n + 1);
+		if (r != n) {
+			tmp = order[n];
+			order[n] = order[r];
+			order[r] = tmp;
+		}
+	}
+
+	return order;
+}
+
+static void dummy_load(struct stress *stress)
+{
+	usleep_range(1000, 2000);
+}
+
+static void stress_inorder_work(struct work_struct *work)
+{
+	struct stress *stress = container_of(work, typeof(*stress), work);
+	const int nlocks = stress->nlocks;
+	struct ww_mutex *locks = stress->locks;
+	struct ww_acquire_ctx ctx;
+	int *order;
+
+	order = get_random_order(nlocks);
+	if (!order)
+		return;
+
+	do {
+		int contended = -1;
+		int n, err;
+
+		ww_acquire_init(&ctx, &ww_class);
+retry:
+		err = 0;
+		for (n = 0; n < nlocks; n++) {
+			if (n == contended)
+				continue;
+
+			err = ww_mutex_lock(&locks[order[n]], &ctx);
+			if (err < 0)
+				break;
+		}
+		if (!err)
+			dummy_load(stress);
+
+		if (contended > n)
+			ww_mutex_unlock(&locks[order[contended]]);
+		contended = n;
+		while (n--)
+			ww_mutex_unlock(&locks[order[n]]);
+
+		if (err == -EDEADLK) {
+			ww_mutex_lock_slow(&locks[order[contended]], &ctx);
+			goto retry;
+		}
+
+		if (err) {
+			pr_err_once("stress (%s) failed with %d\n",
+				    __func__, err);
+			break;
+		}
+
+		ww_acquire_fini(&ctx);
+	} while (!time_after(jiffies, stress->timeout));
+
+	kfree(order);
+}
+
+struct reorder_lock {
+	struct list_head link;
+	struct ww_mutex *lock;
+};
+
+static void stress_reorder_work(struct work_struct *work)
+{
+	struct stress *stress = container_of(work, typeof(*stress), work);
+	LIST_HEAD(locks);
+	struct ww_acquire_ctx ctx;
+	struct reorder_lock *ll, *ln;
+	int *order;
+	int n, err;
+
+	order = get_random_order(stress->nlocks);
+	if (!order)
+		return;
+
+	for (n = 0; n < stress->nlocks; n++) {
+		ll = kmalloc(sizeof(*ll), GFP_KERNEL);
+		if (!ll)
+			goto out;
+
+		ll->lock = &stress->locks[order[n]];
+		list_add(&ll->link, &locks);
+	}
+	kfree(order);
+	order = NULL;
+
+	do {
+		ww_acquire_init(&ctx, &ww_class);
+
+		list_for_each_entry(ll, &locks, link) {
+			err = ww_mutex_lock(ll->lock, &ctx);
+			if (!err)
+				continue;
+
+			ln = ll;
+			list_for_each_entry_continue_reverse(ln, &locks, link)
+				ww_mutex_unlock(ln->lock);
+
+			if (err != -EDEADLK) {
+				pr_err_once("stress (%s) failed with %d\n",
+					    __func__, err);
+				break;
+			}
+
+			ww_mutex_lock_slow(ll->lock, &ctx);
+			list_move(&ll->link, &locks); /* restarts iteration */
+		}
+
+		dummy_load(stress);
+		list_for_each_entry(ll, &locks, link)
+			ww_mutex_unlock(ll->lock);
+
+		ww_acquire_fini(&ctx);
+	} while (!time_after(jiffies, stress->timeout));
+
+out:
+	list_for_each_entry_safe(ll, ln, &locks, link)
+		kfree(ll);
+	kfree(order);
+}
+
+static void stress_one_work(struct work_struct *work)
+{
+	struct stress *stress = container_of(work, typeof(*stress), work);
+	const int nlocks = stress->nlocks;
+	struct ww_mutex *lock = stress->locks + prandom_u32_max(nlocks);
+	int err;
+
+	do {
+		err = ww_mutex_lock(lock, NULL);
+		if (!err) {
+			dummy_load(stress);
+			ww_mutex_unlock(lock);
+		} else {
+			pr_err_once("stress (%s) failed with %d\n",
+				    __func__, err);
+			break;
+		}
+	} while (!time_after(jiffies, stress->timeout));
+}
+
+#define STRESS_INORDER BIT(0)
+#define STRESS_REORDER BIT(1)
+#define STRESS_ONE BIT(2)
+#define STRESS_ALL (STRESS_INORDER | STRESS_REORDER | STRESS_ONE)
+
+static int stress(int nlocks, int nthreads, unsigned int flags)
+{
+	struct ww_mutex *locks;
+	struct stress *stress_array;
+	int n, count;
+
+	locks = kmalloc_array(nlocks, sizeof(*locks), GFP_KERNEL);
+	if (!locks)
+		return -ENOMEM;
+
+	stress_array = kmalloc_array(nthreads, sizeof(*stress_array),
+				     GFP_KERNEL);
+	if (!stress_array) {
+		kfree(locks);
+		return -ENOMEM;
+	}
+
+	for (n = 0; n < nlocks; n++)
+		ww_mutex_init(&locks[n], &ww_class);
+
+	count = 0;
+	for (n = 0; nthreads; n++) {
+		struct stress *stress;
+		void (*fn)(struct work_struct *work);
+
+		fn = NULL;
+		switch (n & 3) {
+		case 0:
+			if (flags & STRESS_INORDER)
+				fn = stress_inorder_work;
+			break;
+		case 1:
+			if (flags & STRESS_REORDER)
+				fn = stress_reorder_work;
+			break;
+		case 2:
+			if (flags & STRESS_ONE)
+				fn = stress_one_work;
+			break;
+		}
+
+		if (!fn)
+			continue;
+
+		stress = &stress_array[count++];
+
+		INIT_WORK(&stress->work, fn);
+		stress->locks = locks;
+		stress->nlocks = nlocks;
+		stress->timeout = jiffies + 2*HZ;
+
+		queue_work(wq, &stress->work);
+		nthreads--;
+	}
+
+	flush_workqueue(wq);
+
+	for (n = 0; n < nlocks; n++)
+		ww_mutex_destroy(&locks[n]);
+	kfree(stress_array);
+	kfree(locks);
+
+	return 0;
+}
+
+static int __init test_ww_mutex_init(void)
+{
+	int ncpus = num_online_cpus();
+	int ret, i;
+
+	printk(KERN_INFO "Beginning ww mutex selftests\n");
+
+	wq = alloc_workqueue("test-ww_mutex", WQ_UNBOUND, 0);
+	if (!wq)
+		return -ENOMEM;
+
+	ret = test_mutex();
+	if (ret)
+		return ret;
+
+	ret = test_aa(false);
+	if (ret)
+		return ret;
+
+	ret = test_aa(true);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < 4; i++) {
+		ret = test_abba(i & 1, i & 2);
+		if (ret)
+			return ret;
+	}
+
+	ret = test_cycle(ncpus);
+	if (ret)
+		return ret;
+
+	ret = stress(16, 2*ncpus, STRESS_INORDER);
+	if (ret)
+		return ret;
+
+	ret = stress(16, 2*ncpus, STRESS_REORDER);
+	if (ret)
+		return ret;
+
+	ret = stress(4095, hweight32(STRESS_ALL)*ncpus, STRESS_ALL);
+	if (ret)
+		return ret;
+
+	printk(KERN_INFO "All ww mutex selftests passed\n");
+	return 0;
+}
+
+static void __exit test_ww_mutex_exit(void)
+{
+	destroy_workqueue(wq);
+}
+
+module_init(test_ww_mutex_init);
+module_exit(test_ww_mutex_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Intel Corporation");
diff --git a/kernel/locking/ww_mutex.h b/kernel/locking/ww_mutex.h
new file mode 100644
index 000000000..3ad2cc482
--- /dev/null
+++ b/kernel/locking/ww_mutex.h
@@ -0,0 +1,569 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef WW_RT
+
+#define MUTEX		mutex
+#define MUTEX_WAITER	mutex_waiter
+
+static inline struct mutex_waiter *
+__ww_waiter_first(struct mutex *lock)
+{
+	struct mutex_waiter *w;
+
+	w = list_first_entry(&lock->wait_list, struct mutex_waiter, list);
+	if (list_entry_is_head(w, &lock->wait_list, list))
+		return NULL;
+
+	return w;
+}
+
+static inline struct mutex_waiter *
+__ww_waiter_next(struct mutex *lock, struct mutex_waiter *w)
+{
+	w = list_next_entry(w, list);
+	if (list_entry_is_head(w, &lock->wait_list, list))
+		return NULL;
+
+	return w;
+}
+
+static inline struct mutex_waiter *
+__ww_waiter_prev(struct mutex *lock, struct mutex_waiter *w)
+{
+	w = list_prev_entry(w, list);
+	if (list_entry_is_head(w, &lock->wait_list, list))
+		return NULL;
+
+	return w;
+}
+
+static inline struct mutex_waiter *
+__ww_waiter_last(struct mutex *lock)
+{
+	struct mutex_waiter *w;
+
+	w = list_last_entry(&lock->wait_list, struct mutex_waiter, list);
+	if (list_entry_is_head(w, &lock->wait_list, list))
+		return NULL;
+
+	return w;
+}
+
+static inline void
+__ww_waiter_add(struct mutex *lock, struct mutex_waiter *waiter, struct mutex_waiter *pos)
+{
+	struct list_head *p = &lock->wait_list;
+	if (pos)
+		p = &pos->list;
+	__mutex_add_waiter(lock, waiter, p);
+}
+
+static inline struct task_struct *
+__ww_mutex_owner(struct mutex *lock)
+{
+	return __mutex_owner(lock);
+}
+
+static inline bool
+__ww_mutex_has_waiters(struct mutex *lock)
+{
+	return atomic_long_read(&lock->owner) & MUTEX_FLAG_WAITERS;
+}
+
+static inline void lock_wait_lock(struct mutex *lock)
+{
+	raw_spin_lock(&lock->wait_lock);
+}
+
+static inline void unlock_wait_lock(struct mutex *lock)
+{
+	raw_spin_unlock(&lock->wait_lock);
+}
+
+static inline void lockdep_assert_wait_lock_held(struct mutex *lock)
+{
+	lockdep_assert_held(&lock->wait_lock);
+}
+
+#else /* WW_RT */
+
+#define MUTEX		rt_mutex
+#define MUTEX_WAITER	rt_mutex_waiter
+
+static inline struct rt_mutex_waiter *
+__ww_waiter_first(struct rt_mutex *lock)
+{
+	struct rb_node *n = rb_first(&lock->rtmutex.waiters.rb_root);
+	if (!n)
+		return NULL;
+	return rb_entry(n, struct rt_mutex_waiter, tree.entry);
+}
+
+static inline struct rt_mutex_waiter *
+__ww_waiter_next(struct rt_mutex *lock, struct rt_mutex_waiter *w)
+{
+	struct rb_node *n = rb_next(&w->tree.entry);
+	if (!n)
+		return NULL;
+	return rb_entry(n, struct rt_mutex_waiter, tree.entry);
+}
+
+static inline struct rt_mutex_waiter *
+__ww_waiter_prev(struct rt_mutex *lock, struct rt_mutex_waiter *w)
+{
+	struct rb_node *n = rb_prev(&w->tree.entry);
+	if (!n)
+		return NULL;
+	return rb_entry(n, struct rt_mutex_waiter, tree.entry);
+}
+
+static inline struct rt_mutex_waiter *
+__ww_waiter_last(struct rt_mutex *lock)
+{
+	struct rb_node *n = rb_last(&lock->rtmutex.waiters.rb_root);
+	if (!n)
+		return NULL;
+	return rb_entry(n, struct rt_mutex_waiter, tree.entry);
+}
+
+static inline void
+__ww_waiter_add(struct rt_mutex *lock, struct rt_mutex_waiter *waiter, struct rt_mutex_waiter *pos)
+{
+	/* RT unconditionally adds the waiter first and then removes it on error */
+}
+
+static inline struct task_struct *
+__ww_mutex_owner(struct rt_mutex *lock)
+{
+	return rt_mutex_owner(&lock->rtmutex);
+}
+
+static inline bool
+__ww_mutex_has_waiters(struct rt_mutex *lock)
+{
+	return rt_mutex_has_waiters(&lock->rtmutex);
+}
+
+static inline void lock_wait_lock(struct rt_mutex *lock)
+{
+	raw_spin_lock(&lock->rtmutex.wait_lock);
+}
+
+static inline void unlock_wait_lock(struct rt_mutex *lock)
+{
+	raw_spin_unlock(&lock->rtmutex.wait_lock);
+}
+
+static inline void lockdep_assert_wait_lock_held(struct rt_mutex *lock)
+{
+	lockdep_assert_held(&lock->rtmutex.wait_lock);
+}
+
+#endif /* WW_RT */
+
+/*
+ * Wait-Die:
+ *   The newer transactions are killed when:
+ *     It (the new transaction) makes a request for a lock being held
+ *     by an older transaction.
+ *
+ * Wound-Wait:
+ *   The newer transactions are wounded when:
+ *     An older transaction makes a request for a lock being held by
+ *     the newer transaction.
+ */
+
+/*
+ * Associate the ww_mutex @ww with the context @ww_ctx under which we acquired
+ * it.
+ */
+static __always_inline void
+ww_mutex_lock_acquired(struct ww_mutex *ww, struct ww_acquire_ctx *ww_ctx)
+{
+#ifdef DEBUG_WW_MUTEXES
+	/*
+	 * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
+	 * but released with a normal mutex_unlock in this call.
+	 *
+	 * This should never happen, always use ww_mutex_unlock.
+	 */
+	DEBUG_LOCKS_WARN_ON(ww->ctx);
+
+	/*
+	 * Not quite done after calling ww_acquire_done() ?
+	 */
+	DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire);
+
+	if (ww_ctx->contending_lock) {
+		/*
+		 * After -EDEADLK you tried to
+		 * acquire a different ww_mutex? Bad!
+		 */
+		DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww);
+
+		/*
+		 * You called ww_mutex_lock after receiving -EDEADLK,
+		 * but 'forgot' to unlock everything else first?
+		 */
+		DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0);
+		ww_ctx->contending_lock = NULL;
+	}
+
+	/*
+	 * Naughty, using a different class will lead to undefined behavior!
+	 */
+	DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class);
+#endif
+	ww_ctx->acquired++;
+	ww->ctx = ww_ctx;
+}
+
+/*
+ * Determine if @a is 'less' than @b. IOW, either @a is a lower priority task
+ * or, when of equal priority, a younger transaction than @b.
+ *
+ * Depending on the algorithm, @a will either need to wait for @b, or die.
+ */
+static inline bool
+__ww_ctx_less(struct ww_acquire_ctx *a, struct ww_acquire_ctx *b)
+{
+/*
+ * Can only do the RT prio for WW_RT, because task->prio isn't stable due to PI,
+ * so the wait_list ordering will go wobbly. rt_mutex re-queues the waiter and
+ * isn't affected by this.
+ */
+#ifdef WW_RT
+	/* kernel prio; less is more */
+	int a_prio = a->task->prio;
+	int b_prio = b->task->prio;
+
+	if (rt_prio(a_prio) || rt_prio(b_prio)) {
+
+		if (a_prio > b_prio)
+			return true;
+
+		if (a_prio < b_prio)
+			return false;
+
+		/* equal static prio */
+
+		if (dl_prio(a_prio)) {
+			if (dl_time_before(b->task->dl.deadline,
+					   a->task->dl.deadline))
+				return true;
+
+			if (dl_time_before(a->task->dl.deadline,
+					   b->task->dl.deadline))
+				return false;
+		}
+
+		/* equal prio */
+	}
+#endif
+
+	/* FIFO order tie break -- bigger is younger */
+	return (signed long)(a->stamp - b->stamp) > 0;
+}
+
+/*
+ * Wait-Die; wake a lesser waiter context (when locks held) such that it can
+ * die.
+ *
+ * Among waiters with context, only the first one can have other locks acquired
+ * already (ctx->acquired > 0), because __ww_mutex_add_waiter() and
+ * __ww_mutex_check_kill() wake any but the earliest context.
+ */
+static bool
+__ww_mutex_die(struct MUTEX *lock, struct MUTEX_WAITER *waiter,
+	       struct ww_acquire_ctx *ww_ctx)
+{
+	if (!ww_ctx->is_wait_die)
+		return false;
+
+	if (waiter->ww_ctx->acquired > 0 && __ww_ctx_less(waiter->ww_ctx, ww_ctx)) {
+#ifndef WW_RT
+		debug_mutex_wake_waiter(lock, waiter);
+#endif
+		wake_up_process(waiter->task);
+	}
+
+	return true;
+}
+
+/*
+ * Wound-Wait; wound a lesser @hold_ctx if it holds the lock.
+ *
+ * Wound the lock holder if there are waiters with more important transactions
+ * than the lock holders. Even if multiple waiters may wound the lock holder,
+ * it's sufficient that only one does.
+ */
+static bool __ww_mutex_wound(struct MUTEX *lock,
+			     struct ww_acquire_ctx *ww_ctx,
+			     struct ww_acquire_ctx *hold_ctx)
+{
+	struct task_struct *owner = __ww_mutex_owner(lock);
+
+	lockdep_assert_wait_lock_held(lock);
+
+	/*
+	 * Possible through __ww_mutex_add_waiter() when we race with
+	 * ww_mutex_set_context_fastpath(). In that case we'll get here again
+	 * through __ww_mutex_check_waiters().
+	 */
+	if (!hold_ctx)
+		return false;
+
+	/*
+	 * Can have !owner because of __mutex_unlock_slowpath(), but if owner,
+	 * it cannot go away because we'll have FLAG_WAITERS set and hold
+	 * wait_lock.
+	 */
+	if (!owner)
+		return false;
+
+	if (ww_ctx->acquired > 0 && __ww_ctx_less(hold_ctx, ww_ctx)) {
+		hold_ctx->wounded = 1;
+
+		/*
+		 * wake_up_process() paired with set_current_state()
+		 * inserts sufficient barriers to make sure @owner either sees
+		 * it's wounded in __ww_mutex_check_kill() or has a
+		 * wakeup pending to re-read the wounded state.
+		 */
+		if (owner != current)
+			wake_up_process(owner);
+
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * We just acquired @lock under @ww_ctx, if there are more important contexts
+ * waiting behind us on the wait-list, check if they need to die, or wound us.
+ *
+ * See __ww_mutex_add_waiter() for the list-order construction; basically the
+ * list is ordered by stamp, smallest (oldest) first.
+ *
+ * This relies on never mixing wait-die/wound-wait on the same wait-list;
+ * which is currently ensured by that being a ww_class property.
+ *
+ * The current task must not be on the wait list.
+ */
+static void
+__ww_mutex_check_waiters(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx)
+{
+	struct MUTEX_WAITER *cur;
+
+	lockdep_assert_wait_lock_held(lock);
+
+	for (cur = __ww_waiter_first(lock); cur;
+	     cur = __ww_waiter_next(lock, cur)) {
+
+		if (!cur->ww_ctx)
+			continue;
+
+		if (__ww_mutex_die(lock, cur, ww_ctx) ||
+		    __ww_mutex_wound(lock, cur->ww_ctx, ww_ctx))
+			break;
+	}
+}
+
+/*
+ * After acquiring lock with fastpath, where we do not hold wait_lock, set ctx
+ * and wake up any waiters so they can recheck.
+ */
+static __always_inline void
+ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	ww_mutex_lock_acquired(lock, ctx);
+
+	/*
+	 * The lock->ctx update should be visible on all cores before
+	 * the WAITERS check is done, otherwise contended waiters might be
+	 * missed. The contended waiters will either see ww_ctx == NULL
+	 * and keep spinning, or it will acquire wait_lock, add itself
+	 * to waiter list and sleep.
+	 */
+	smp_mb(); /* See comments above and below. */
+
+	/*
+	 * [W] ww->ctx = ctx	    [W] MUTEX_FLAG_WAITERS
+	 *     MB		        MB
+	 * [R] MUTEX_FLAG_WAITERS   [R] ww->ctx
+	 *
+	 * The memory barrier above pairs with the memory barrier in
+	 * __ww_mutex_add_waiter() and makes sure we either observe ww->ctx
+	 * and/or !empty list.
+	 */
+	if (likely(!__ww_mutex_has_waiters(&lock->base)))
+		return;
+
+	/*
+	 * Uh oh, we raced in fastpath, check if any of the waiters need to
+	 * die or wound us.
+	 */
+	lock_wait_lock(&lock->base);
+	__ww_mutex_check_waiters(&lock->base, ctx);
+	unlock_wait_lock(&lock->base);
+}
+
+static __always_inline int
+__ww_mutex_kill(struct MUTEX *lock, struct ww_acquire_ctx *ww_ctx)
+{
+	if (ww_ctx->acquired > 0) {
+#ifdef DEBUG_WW_MUTEXES
+		struct ww_mutex *ww;
+
+		ww = container_of(lock, struct ww_mutex, base);
+		DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock);
+		ww_ctx->contending_lock = ww;
+#endif
+		return -EDEADLK;
+	}
+
+	return 0;
+}
+
+/*
+ * Check the wound condition for the current lock acquire.
+ *
+ * Wound-Wait: If we're wounded, kill ourself.
+ *
+ * Wait-Die: If we're trying to acquire a lock already held by an older
+ *           context, kill ourselves.
+ *
+ * Since __ww_mutex_add_waiter() orders the wait-list on stamp, we only have to
+ * look at waiters before us in the wait-list.
+ */
+static inline int
+__ww_mutex_check_kill(struct MUTEX *lock, struct MUTEX_WAITER *waiter,
+		      struct ww_acquire_ctx *ctx)
+{
+	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+	struct ww_acquire_ctx *hold_ctx = READ_ONCE(ww->ctx);
+	struct MUTEX_WAITER *cur;
+
+	if (ctx->acquired == 0)
+		return 0;
+
+	if (!ctx->is_wait_die) {
+		if (ctx->wounded)
+			return __ww_mutex_kill(lock, ctx);
+
+		return 0;
+	}
+
+	if (hold_ctx && __ww_ctx_less(ctx, hold_ctx))
+		return __ww_mutex_kill(lock, ctx);
+
+	/*
+	 * If there is a waiter in front of us that has a context, then its
+	 * stamp is earlier than ours and we must kill ourself.
+	 */
+	for (cur = __ww_waiter_prev(lock, waiter); cur;
+	     cur = __ww_waiter_prev(lock, cur)) {
+
+		if (!cur->ww_ctx)
+			continue;
+
+		return __ww_mutex_kill(lock, ctx);
+	}
+
+	return 0;
+}
+
+/*
+ * Add @waiter to the wait-list, keep the wait-list ordered by stamp, smallest
+ * first. Such that older contexts are preferred to acquire the lock over
+ * younger contexts.
+ *
+ * Waiters without context are interspersed in FIFO order.
+ *
+ * Furthermore, for Wait-Die kill ourself immediately when possible (there are
+ * older contexts already waiting) to avoid unnecessary waiting and for
+ * Wound-Wait ensure we wound the owning context when it is younger.
+ */
+static inline int
+__ww_mutex_add_waiter(struct MUTEX_WAITER *waiter,
+		      struct MUTEX *lock,
+		      struct ww_acquire_ctx *ww_ctx)
+{
+	struct MUTEX_WAITER *cur, *pos = NULL;
+	bool is_wait_die;
+
+	if (!ww_ctx) {
+		__ww_waiter_add(lock, waiter, NULL);
+		return 0;
+	}
+
+	is_wait_die = ww_ctx->is_wait_die;
+
+	/*
+	 * Add the waiter before the first waiter with a higher stamp.
+	 * Waiters without a context are skipped to avoid starving
+	 * them. Wait-Die waiters may die here. Wound-Wait waiters
+	 * never die here, but they are sorted in stamp order and
+	 * may wound the lock holder.
+	 */
+	for (cur = __ww_waiter_last(lock); cur;
+	     cur = __ww_waiter_prev(lock, cur)) {
+
+		if (!cur->ww_ctx)
+			continue;
+
+		if (__ww_ctx_less(ww_ctx, cur->ww_ctx)) {
+			/*
+			 * Wait-Die: if we find an older context waiting, there
+			 * is no point in queueing behind it, as we'd have to
+			 * die the moment it would acquire the lock.
+			 */
+			if (is_wait_die) {
+				int ret = __ww_mutex_kill(lock, ww_ctx);
+
+				if (ret)
+					return ret;
+			}
+
+			break;
+		}
+
+		pos = cur;
+
+		/* Wait-Die: ensure younger waiters die. */
+		__ww_mutex_die(lock, cur, ww_ctx);
+	}
+
+	__ww_waiter_add(lock, waiter, pos);
+
+	/*
+	 * Wound-Wait: if we're blocking on a mutex owned by a younger context,
+	 * wound that such that we might proceed.
+	 */
+	if (!is_wait_die) {
+		struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
+
+		/*
+		 * See ww_mutex_set_context_fastpath(). Orders setting
+		 * MUTEX_FLAG_WAITERS vs the ww->ctx load,
+		 * such that either we or the fastpath will wound @ww->ctx.
+		 */
+		smp_mb();
+		__ww_mutex_wound(lock, ww_ctx, ww->ctx);
+	}
+
+	return 0;
+}
+
+static inline void __ww_mutex_unlock(struct ww_mutex *lock)
+{
+	if (lock->ctx) {
+#ifdef DEBUG_WW_MUTEXES
+		DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
+#endif
+		if (lock->ctx->acquired > 0)
+			lock->ctx->acquired--;
+		lock->ctx = NULL;
+	}
+}
diff --git a/kernel/locking/ww_rt_mutex.c b/kernel/locking/ww_rt_mutex.c
new file mode 100644
index 000000000..d1473c624
--- /dev/null
+++ b/kernel/locking/ww_rt_mutex.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * rtmutex API
+ */
+#include <linux/spinlock.h>
+#include <linux/export.h>
+
+#define RT_MUTEX_BUILD_MUTEX
+#define WW_RT
+#include "rtmutex.c"
+
+int ww_mutex_trylock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx)
+{
+	struct rt_mutex *rtm = &lock->base;
+
+	if (!ww_ctx)
+		return rt_mutex_trylock(rtm);
+
+	/*
+	 * Reset the wounded flag after a kill. No other process can
+	 * race and wound us here, since they can't have a valid owner
+	 * pointer if we don't have any locks held.
+	 */
+	if (ww_ctx->acquired == 0)
+		ww_ctx->wounded = 0;
+
+	if (__rt_mutex_trylock(&rtm->rtmutex)) {
+		ww_mutex_set_context_fastpath(lock, ww_ctx);
+		mutex_acquire_nest(&rtm->dep_map, 0, 1, &ww_ctx->dep_map, _RET_IP_);
+		return 1;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(ww_mutex_trylock);
+
+static int __sched
+__ww_rt_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx,
+		   unsigned int state, unsigned long ip)
+{
+	struct lockdep_map __maybe_unused *nest_lock = NULL;
+	struct rt_mutex *rtm = &lock->base;
+	int ret;
+
+	might_sleep();
+
+	if (ww_ctx) {
+		if (unlikely(ww_ctx == READ_ONCE(lock->ctx)))
+			return -EALREADY;
+
+		/*
+		 * Reset the wounded flag after a kill. No other process can
+		 * race and wound us here, since they can't have a valid owner
+		 * pointer if we don't have any locks held.
+		 */
+		if (ww_ctx->acquired == 0)
+			ww_ctx->wounded = 0;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+		nest_lock = &ww_ctx->dep_map;
+#endif
+	}
+	mutex_acquire_nest(&rtm->dep_map, 0, 0, nest_lock, ip);
+
+	if (likely(rt_mutex_cmpxchg_acquire(&rtm->rtmutex, NULL, current))) {
+		if (ww_ctx)
+			ww_mutex_set_context_fastpath(lock, ww_ctx);
+		return 0;
+	}
+
+	ret = rt_mutex_slowlock(&rtm->rtmutex, ww_ctx, state);
+
+	if (ret)
+		mutex_release(&rtm->dep_map, ip);
+	return ret;
+}
+
+int __sched
+ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	return __ww_rt_mutex_lock(lock, ctx, TASK_UNINTERRUPTIBLE, _RET_IP_);
+}
+EXPORT_SYMBOL(ww_mutex_lock);
+
+int __sched
+ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	return __ww_rt_mutex_lock(lock, ctx, TASK_INTERRUPTIBLE, _RET_IP_);
+}
+EXPORT_SYMBOL(ww_mutex_lock_interruptible);
+
+void __sched ww_mutex_unlock(struct ww_mutex *lock)
+{
+	struct rt_mutex *rtm = &lock->base;
+
+	__ww_mutex_unlock(lock);
+
+	mutex_release(&rtm->dep_map, _RET_IP_);
+	__rt_mutex_unlock(&rtm->rtmutex);
+}
+EXPORT_SYMBOL(ww_mutex_unlock);
diff --git a/kernel/module/Kconfig b/kernel/module/Kconfig
new file mode 100644
index 000000000..26ea5d04f
--- /dev/null
+++ b/kernel/module/Kconfig
@@ -0,0 +1,293 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menuconfig MODULES
+	bool "Enable loadable module support"
+	modules
+	help
+	  Kernel modules are small pieces of compiled code which can
+	  be inserted in the running kernel, rather than being
+	  permanently built into the kernel.  You use the "modprobe"
+	  tool to add (and sometimes remove) them.  If you say Y here,
+	  many parts of the kernel can be built as modules (by
+	  answering M instead of Y where indicated): this is most
+	  useful for infrequently used options which are not required
+	  for booting.  For more information, see the man pages for
+	  modprobe, lsmod, modinfo, insmod and rmmod.
+
+	  If you say Y here, you will need to run "make
+	  modules_install" to put the modules under /lib/modules/
+	  where modprobe can find them (you may need to be root to do
+	  this).
+
+	  If unsure, say Y.
+
+if MODULES
+
+config MODULE_FORCE_LOAD
+	bool "Forced module loading"
+	default n
+	help
+	  Allow loading of modules without version information (ie. modprobe
+	  --force).  Forced module loading sets the 'F' (forced) taint flag and
+	  is usually a really bad idea.
+
+config MODULE_UNLOAD
+	bool "Module unloading"
+	help
+	  Without this option you will not be able to unload any
+	  modules (note that some modules may not be unloadable
+	  anyway), which makes your kernel smaller, faster
+	  and simpler.  If unsure, say Y.
+
+config MODULE_FORCE_UNLOAD
+	bool "Forced module unloading"
+	depends on MODULE_UNLOAD
+	help
+	  This option allows you to force a module to unload, even if the
+	  kernel believes it is unsafe: the kernel will remove the module
+	  without waiting for anyone to stop using it (using the -f option to
+	  rmmod).  This is mainly for kernel developers and desperate users.
+	  If unsure, say N.
+
+config MODULE_UNLOAD_TAINT_TRACKING
+	bool "Tainted module unload tracking"
+	depends on MODULE_UNLOAD
+	default n
+	help
+	  This option allows you to maintain a record of each unloaded
+	  module that tainted the kernel. In addition to displaying a
+	  list of linked (or loaded) modules e.g. on detection of a bad
+	  page (see bad_page()), the aforementioned details are also
+	  shown. If unsure, say N.
+
+config MODVERSIONS
+	bool "Module versioning support"
+	help
+	  Usually, you have to use modules compiled with your kernel.
+	  Saying Y here makes it sometimes possible to use modules
+	  compiled for different kernels, by adding enough information
+	  to the modules to (hopefully) spot any changes which would
+	  make them incompatible with the kernel you are running.  If
+	  unsure, say N.
+
+config ASM_MODVERSIONS
+	bool
+	default HAVE_ASM_MODVERSIONS && MODVERSIONS
+	help
+	  This enables module versioning for exported symbols also from
+	  assembly. This can be enabled only when the target architecture
+	  supports it.
+
+config MODULE_SRCVERSION_ALL
+	bool "Source checksum for all modules"
+	help
+	  Modules which contain a MODULE_VERSION get an extra "srcversion"
+	  field inserted into their modinfo section, which contains a
+	  sum of the source files which made it.  This helps maintainers
+	  see exactly which source was used to build a module (since
+	  others sometimes change the module source without updating
+	  the version).  With this option, such a "srcversion" field
+	  will be created for all modules.  If unsure, say N.
+
+config MODULE_SIG
+	bool "Module signature verification"
+	select MODULE_SIG_FORMAT
+	help
+	  Check modules for valid signatures upon load: the signature
+	  is simply appended to the module. For more information see
+	  <file:Documentation/admin-guide/module-signing.rst>.
+
+	  Note that this option adds the OpenSSL development packages as a
+	  kernel build dependency so that the signing tool can use its crypto
+	  library.
+
+	  You should enable this option if you wish to use either
+	  CONFIG_SECURITY_LOCKDOWN_LSM or lockdown functionality imposed via
+	  another LSM - otherwise unsigned modules will be loadable regardless
+	  of the lockdown policy.
+
+	  !!!WARNING!!!  If you enable this option, you MUST make sure that the
+	  module DOES NOT get stripped after being signed.  This includes the
+	  debuginfo strip done by some packagers (such as rpmbuild) and
+	  inclusion into an initramfs that wants the module size reduced.
+
+config MODULE_SIG_FORCE
+	bool "Require modules to be validly signed"
+	depends on MODULE_SIG
+	help
+	  Reject unsigned modules or signed modules for which we don't have a
+	  key.  Without this, such modules will simply taint the kernel.
+
+config MODULE_SIG_ALL
+	bool "Automatically sign all modules"
+	default y
+	depends on MODULE_SIG || IMA_APPRAISE_MODSIG
+	help
+	  Sign all modules during make modules_install. Without this option,
+	  modules must be signed manually, using the scripts/sign-file tool.
+
+comment "Do not forget to sign required modules with scripts/sign-file"
+	depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
+
+choice
+	prompt "Which hash algorithm should modules be signed with?"
+	depends on MODULE_SIG || IMA_APPRAISE_MODSIG
+	help
+	  This determines which sort of hashing algorithm will be used during
+	  signature generation.  This algorithm _must_ be built into the kernel
+	  directly so that signature verification can take place.  It is not
+	  possible to load a signed module containing the algorithm to check
+	  the signature on that module.
+
+config MODULE_SIG_SHA1
+	bool "Sign modules with SHA-1"
+	select CRYPTO_SHA1
+
+config MODULE_SIG_SHA224
+	bool "Sign modules with SHA-224"
+	select CRYPTO_SHA256
+
+config MODULE_SIG_SHA256
+	bool "Sign modules with SHA-256"
+	select CRYPTO_SHA256
+
+config MODULE_SIG_SHA384
+	bool "Sign modules with SHA-384"
+	select CRYPTO_SHA512
+
+config MODULE_SIG_SHA512
+	bool "Sign modules with SHA-512"
+	select CRYPTO_SHA512
+
+endchoice
+
+config MODULE_SIG_HASH
+	string
+	depends on MODULE_SIG || IMA_APPRAISE_MODSIG
+	default "sha1" if MODULE_SIG_SHA1
+	default "sha224" if MODULE_SIG_SHA224
+	default "sha256" if MODULE_SIG_SHA256
+	default "sha384" if MODULE_SIG_SHA384
+	default "sha512" if MODULE_SIG_SHA512
+
+choice
+	prompt "Module compression mode"
+	help
+	  This option allows you to choose the algorithm which will be used to
+	  compress modules when 'make modules_install' is run. (or, you can
+	  choose to not compress modules at all.)
+
+	  External modules will also be compressed in the same way during the
+	  installation.
+
+	  For modules inside an initrd or initramfs, it's more efficient to
+	  compress the whole initrd or initramfs instead.
+
+	  This is fully compatible with signed modules.
+
+	  Please note that the tool used to load modules needs to support the
+	  corresponding algorithm. module-init-tools MAY support gzip, and kmod
+	  MAY support gzip, xz and zstd.
+
+	  Your build system needs to provide the appropriate compression tool
+	  to compress the modules.
+
+	  If in doubt, select 'None'.
+
+config MODULE_COMPRESS_NONE
+	bool "None"
+	help
+	  Do not compress modules. The installed modules are suffixed
+	  with .ko.
+
+config MODULE_COMPRESS_GZIP
+	bool "GZIP"
+	help
+	  Compress modules with GZIP. The installed modules are suffixed
+	  with .ko.gz.
+
+config MODULE_COMPRESS_XZ
+	bool "XZ"
+	help
+	  Compress modules with XZ. The installed modules are suffixed
+	  with .ko.xz.
+
+config MODULE_COMPRESS_ZSTD
+	bool "ZSTD"
+	help
+	  Compress modules with ZSTD. The installed modules are suffixed
+	  with .ko.zst.
+
+endchoice
+
+config MODULE_DECOMPRESS
+	bool "Support in-kernel module decompression"
+	depends on MODULE_COMPRESS_GZIP || MODULE_COMPRESS_XZ
+	select ZLIB_INFLATE if MODULE_COMPRESS_GZIP
+	select XZ_DEC if MODULE_COMPRESS_XZ
+	help
+
+	  Support for decompressing kernel modules by the kernel itself
+	  instead of relying on userspace to perform this task. Useful when
+	  load pinning security policy is enabled.
+
+	  If unsure, say N.
+
+config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
+	bool "Allow loading of modules with missing namespace imports"
+	help
+	  Symbols exported with EXPORT_SYMBOL_NS*() are considered exported in
+	  a namespace. A module that makes use of a symbol exported with such a
+	  namespace is required to import the namespace via MODULE_IMPORT_NS().
+	  There is no technical reason to enforce correct namespace imports,
+	  but it creates consistency between symbols defining namespaces and
+	  users importing namespaces they make use of. This option relaxes this
+	  requirement and lifts the enforcement when loading a module.
+
+	  If unsure, say N.
+
+config MODPROBE_PATH
+	string "Path to modprobe binary"
+	default "/sbin/modprobe"
+	help
+	  When kernel code requests a module, it does so by calling
+	  the "modprobe" userspace utility. This option allows you to
+	  set the path where that binary is found. This can be changed
+	  at runtime via the sysctl file
+	  /proc/sys/kernel/modprobe. Setting this to the empty string
+	  removes the kernel's ability to request modules (but
+	  userspace can still load modules explicitly).
+
+config TRIM_UNUSED_KSYMS
+	bool "Trim unused exported kernel symbols" if EXPERT
+	depends on !COMPILE_TEST
+	help
+	  The kernel and some modules make many symbols available for
+	  other modules to use via EXPORT_SYMBOL() and variants. Depending
+	  on the set of modules being selected in your kernel configuration,
+	  many of those exported symbols might never be used.
+
+	  This option allows for unused exported symbols to be dropped from
+	  the build. In turn, this provides the compiler more opportunities
+	  (especially when using LTO) for optimizing the code and reducing
+	  binary size.  This might have some security advantages as well.
+
+	  If unsure, or if you need to build out-of-tree modules, say N.
+
+config UNUSED_KSYMS_WHITELIST
+	string "Whitelist of symbols to keep in ksymtab"
+	depends on TRIM_UNUSED_KSYMS
+	help
+	  By default, all unused exported symbols will be un-exported from the
+	  build when TRIM_UNUSED_KSYMS is selected.
+
+	  UNUSED_KSYMS_WHITELIST allows to whitelist symbols that must be kept
+	  exported at all times, even in absence of in-tree users. The value to
+	  set here is the path to a text file containing the list of symbols,
+	  one per line. The path can be absolute, or relative to the kernel
+	  source tree.
+
+config MODULES_TREE_LOOKUP
+	def_bool y
+	depends on PERF_EVENTS || TRACING || CFI_CLANG
+
+endif # MODULES
diff --git a/kernel/module/Makefile b/kernel/module/Makefile
new file mode 100644
index 000000000..948efea81
--- /dev/null
+++ b/kernel/module/Makefile
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for linux kernel module support
+#
+
+# These are called from save_stack_trace() on slub debug path,
+# and produce insane amounts of uninteresting coverage.
+KCOV_INSTRUMENT_module.o := n
+
+obj-y += main.o strict_rwx.o
+obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o
+obj-$(CONFIG_MODULE_SIG) += signing.o
+obj-$(CONFIG_LIVEPATCH) += livepatch.o
+obj-$(CONFIG_MODULES_TREE_LOOKUP) += tree_lookup.o
+obj-$(CONFIG_DEBUG_KMEMLEAK) += debug_kmemleak.o
+obj-$(CONFIG_KALLSYMS) += kallsyms.o
+obj-$(CONFIG_PROC_FS) += procfs.o
+obj-$(CONFIG_SYSFS) += sysfs.o
+obj-$(CONFIG_KGDB_KDB) += kdb.o
+obj-$(CONFIG_MODVERSIONS) += version.o
+obj-$(CONFIG_MODULE_UNLOAD_TAINT_TRACKING) += tracking.o
diff --git a/kernel/module/debug_kmemleak.c b/kernel/module/debug_kmemleak.c
new file mode 100644
index 000000000..12a569d36
--- /dev/null
+++ b/kernel/module/debug_kmemleak.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module kmemleak support
+ *
+ * Copyright (C) 2009 Catalin Marinas
+ */
+
+#include <linux/module.h>
+#include <linux/kmemleak.h>
+#include "internal.h"
+
+void kmemleak_load_module(const struct module *mod,
+			  const struct load_info *info)
+{
+	unsigned int i;
+
+	/* only scan the sections containing data */
+	kmemleak_scan_area(mod, sizeof(struct module), GFP_KERNEL);
+
+	for (i = 1; i < info->hdr->e_shnum; i++) {
+		/* Scan all writable sections that's not executable */
+		if (!(info->sechdrs[i].sh_flags & SHF_ALLOC) ||
+		    !(info->sechdrs[i].sh_flags & SHF_WRITE) ||
+		    (info->sechdrs[i].sh_flags & SHF_EXECINSTR))
+			continue;
+
+		kmemleak_scan_area((void *)info->sechdrs[i].sh_addr,
+				   info->sechdrs[i].sh_size, GFP_KERNEL);
+	}
+}
diff --git a/kernel/module/decompress.c b/kernel/module/decompress.c
new file mode 100644
index 000000000..e1e9f69c5
--- /dev/null
+++ b/kernel/module/decompress.c
@@ -0,0 +1,276 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2021 Google LLC.
+ */
+
+#include <linux/init.h>
+#include <linux/highmem.h>
+#include <linux/kobject.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/vmalloc.h>
+
+#include "internal.h"
+
+static int module_extend_max_pages(struct load_info *info, unsigned int extent)
+{
+	struct page **new_pages;
+
+	new_pages = kvmalloc_array(info->max_pages + extent,
+				   sizeof(info->pages), GFP_KERNEL);
+	if (!new_pages)
+		return -ENOMEM;
+
+	memcpy(new_pages, info->pages, info->max_pages * sizeof(info->pages));
+	kvfree(info->pages);
+	info->pages = new_pages;
+	info->max_pages += extent;
+
+	return 0;
+}
+
+static struct page *module_get_next_page(struct load_info *info)
+{
+	struct page *page;
+	int error;
+
+	if (info->max_pages == info->used_pages) {
+		error = module_extend_max_pages(info, info->used_pages);
+		if (error)
+			return ERR_PTR(error);
+	}
+
+	page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
+	if (!page)
+		return ERR_PTR(-ENOMEM);
+
+	info->pages[info->used_pages++] = page;
+	return page;
+}
+
+#ifdef CONFIG_MODULE_COMPRESS_GZIP
+#include <linux/zlib.h>
+#define MODULE_COMPRESSION	gzip
+#define MODULE_DECOMPRESS_FN	module_gzip_decompress
+
+/*
+ * Calculate length of the header which consists of signature, header
+ * flags, time stamp and operating system ID (10 bytes total), plus
+ * an optional filename.
+ */
+static size_t module_gzip_header_len(const u8 *buf, size_t size)
+{
+	const u8 signature[] = { 0x1f, 0x8b, 0x08 };
+	size_t len = 10;
+
+	if (size < len || memcmp(buf, signature, sizeof(signature)))
+		return 0;
+
+	if (buf[3] & 0x08) {
+		do {
+			/*
+			 * If we can't find the end of the file name we must
+			 * be dealing with a corrupted file.
+			 */
+			if (len == size)
+				return 0;
+		} while (buf[len++] != '\0');
+	}
+
+	return len;
+}
+
+static ssize_t module_gzip_decompress(struct load_info *info,
+				      const void *buf, size_t size)
+{
+	struct z_stream_s s = { 0 };
+	size_t new_size = 0;
+	size_t gzip_hdr_len;
+	ssize_t retval;
+	int rc;
+
+	gzip_hdr_len = module_gzip_header_len(buf, size);
+	if (!gzip_hdr_len) {
+		pr_err("not a gzip compressed module\n");
+		return -EINVAL;
+	}
+
+	s.next_in = buf + gzip_hdr_len;
+	s.avail_in = size - gzip_hdr_len;
+
+	s.workspace = vmalloc(zlib_inflate_workspacesize());
+	if (!s.workspace)
+		return -ENOMEM;
+
+	rc = zlib_inflateInit2(&s, -MAX_WBITS);
+	if (rc != Z_OK) {
+		pr_err("failed to initialize decompressor: %d\n", rc);
+		retval = -EINVAL;
+		goto out;
+	}
+
+	do {
+		struct page *page = module_get_next_page(info);
+
+		if (IS_ERR(page)) {
+			retval = PTR_ERR(page);
+			goto out_inflate_end;
+		}
+
+		s.next_out = kmap_local_page(page);
+		s.avail_out = PAGE_SIZE;
+		rc = zlib_inflate(&s, 0);
+		kunmap_local(s.next_out);
+
+		new_size += PAGE_SIZE - s.avail_out;
+	} while (rc == Z_OK);
+
+	if (rc != Z_STREAM_END) {
+		pr_err("decompression failed with status %d\n", rc);
+		retval = -EINVAL;
+		goto out_inflate_end;
+	}
+
+	retval = new_size;
+
+out_inflate_end:
+	zlib_inflateEnd(&s);
+out:
+	vfree(s.workspace);
+	return retval;
+}
+#elif CONFIG_MODULE_COMPRESS_XZ
+#include <linux/xz.h>
+#define MODULE_COMPRESSION	xz
+#define MODULE_DECOMPRESS_FN	module_xz_decompress
+
+static ssize_t module_xz_decompress(struct load_info *info,
+				    const void *buf, size_t size)
+{
+	static const u8 signature[] = { 0xfd, '7', 'z', 'X', 'Z', 0 };
+	struct xz_dec *xz_dec;
+	struct xz_buf xz_buf;
+	enum xz_ret xz_ret;
+	size_t new_size = 0;
+	ssize_t retval;
+
+	if (size < sizeof(signature) ||
+	    memcmp(buf, signature, sizeof(signature))) {
+		pr_err("not an xz compressed module\n");
+		return -EINVAL;
+	}
+
+	xz_dec = xz_dec_init(XZ_DYNALLOC, (u32)-1);
+	if (!xz_dec)
+		return -ENOMEM;
+
+	xz_buf.in_size = size;
+	xz_buf.in = buf;
+	xz_buf.in_pos = 0;
+
+	do {
+		struct page *page = module_get_next_page(info);
+
+		if (IS_ERR(page)) {
+			retval = PTR_ERR(page);
+			goto out;
+		}
+
+		xz_buf.out = kmap_local_page(page);
+		xz_buf.out_pos = 0;
+		xz_buf.out_size = PAGE_SIZE;
+		xz_ret = xz_dec_run(xz_dec, &xz_buf);
+		kunmap_local(xz_buf.out);
+
+		new_size += xz_buf.out_pos;
+	} while (xz_buf.out_pos == PAGE_SIZE && xz_ret == XZ_OK);
+
+	if (xz_ret != XZ_STREAM_END) {
+		pr_err("decompression failed with status %d\n", xz_ret);
+		retval = -EINVAL;
+		goto out;
+	}
+
+	retval = new_size;
+
+ out:
+	xz_dec_end(xz_dec);
+	return retval;
+}
+#else
+#error "Unexpected configuration for CONFIG_MODULE_DECOMPRESS"
+#endif
+
+int module_decompress(struct load_info *info, const void *buf, size_t size)
+{
+	unsigned int n_pages;
+	ssize_t data_size;
+	int error;
+
+	/*
+	 * Start with number of pages twice as big as needed for
+	 * compressed data.
+	 */
+	n_pages = DIV_ROUND_UP(size, PAGE_SIZE) * 2;
+	error = module_extend_max_pages(info, n_pages);
+
+	data_size = MODULE_DECOMPRESS_FN(info, buf, size);
+	if (data_size < 0) {
+		error = data_size;
+		goto err;
+	}
+
+	info->hdr = vmap(info->pages, info->used_pages, VM_MAP, PAGE_KERNEL);
+	if (!info->hdr) {
+		error = -ENOMEM;
+		goto err;
+	}
+
+	info->len = data_size;
+	return 0;
+
+err:
+	module_decompress_cleanup(info);
+	return error;
+}
+
+void module_decompress_cleanup(struct load_info *info)
+{
+	int i;
+
+	if (info->hdr)
+		vunmap(info->hdr);
+
+	for (i = 0; i < info->used_pages; i++)
+		__free_page(info->pages[i]);
+
+	kvfree(info->pages);
+
+	info->pages = NULL;
+	info->max_pages = info->used_pages = 0;
+}
+
+#ifdef CONFIG_SYSFS
+static ssize_t compression_show(struct kobject *kobj,
+				struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, __stringify(MODULE_COMPRESSION) "\n");
+}
+
+static struct kobj_attribute module_compression_attr = __ATTR_RO(compression);
+
+static int __init module_decompress_sysfs_init(void)
+{
+	int error;
+
+	error = sysfs_create_file(&module_kset->kobj,
+				  &module_compression_attr.attr);
+	if (error)
+		pr_warn("Failed to create 'compression' attribute");
+
+	return 0;
+}
+late_initcall(module_decompress_sysfs_init);
+#endif
diff --git a/kernel/module/internal.h b/kernel/module/internal.h
new file mode 100644
index 000000000..2e2bf236f
--- /dev/null
+++ b/kernel/module/internal.h
@@ -0,0 +1,305 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Module internals
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/elf.h>
+#include <linux/compiler.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/rculist.h>
+#include <linux/rcupdate.h>
+#include <linux/mm.h>
+
+#ifndef ARCH_SHF_SMALL
+#define ARCH_SHF_SMALL 0
+#endif
+
+/* If this is set, the section belongs in the init part of the module */
+#define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG - 1))
+/* Maximum number of characters written by module_flags() */
+#define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)
+
+#ifndef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+#define	data_layout core_layout
+#endif
+
+/*
+ * Modules' sections will be aligned on page boundaries
+ * to ensure complete separation of code and data, but
+ * only when CONFIG_STRICT_MODULE_RWX=y
+ */
+static inline unsigned int strict_align(unsigned int size)
+{
+	if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
+		return PAGE_ALIGN(size);
+	else
+		return size;
+}
+
+extern struct mutex module_mutex;
+extern struct list_head modules;
+
+extern struct module_attribute *modinfo_attrs[];
+extern size_t modinfo_attrs_count;
+
+/* Provided by the linker */
+extern const struct kernel_symbol __start___ksymtab[];
+extern const struct kernel_symbol __stop___ksymtab[];
+extern const struct kernel_symbol __start___ksymtab_gpl[];
+extern const struct kernel_symbol __stop___ksymtab_gpl[];
+extern const s32 __start___kcrctab[];
+extern const s32 __start___kcrctab_gpl[];
+
+#include <linux/dynamic_debug.h>
+struct load_info {
+	const char *name;
+	/* pointer to module in temporary copy, freed at end of load_module() */
+	struct module *mod;
+	Elf_Ehdr *hdr;
+	unsigned long len;
+	Elf_Shdr *sechdrs;
+	char *secstrings, *strtab;
+	unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs;
+	struct _ddebug_info dyndbg;
+	bool sig_ok;
+#ifdef CONFIG_KALLSYMS
+	unsigned long mod_kallsyms_init_off;
+#endif
+#ifdef CONFIG_MODULE_DECOMPRESS
+	struct page **pages;
+	unsigned int max_pages;
+	unsigned int used_pages;
+#endif
+	struct {
+		unsigned int sym, str, mod, vers, info, pcpu;
+	} index;
+};
+
+enum mod_license {
+	NOT_GPL_ONLY,
+	GPL_ONLY,
+};
+
+struct find_symbol_arg {
+	/* Input */
+	const char *name;
+	bool gplok;
+	bool warn;
+
+	/* Output */
+	struct module *owner;
+	const s32 *crc;
+	const struct kernel_symbol *sym;
+	enum mod_license license;
+};
+
+int mod_verify_sig(const void *mod, struct load_info *info);
+int try_to_force_load(struct module *mod, const char *reason);
+bool find_symbol(struct find_symbol_arg *fsa);
+struct module *find_module_all(const char *name, size_t len, bool even_unformed);
+int cmp_name(const void *name, const void *sym);
+long module_get_offset(struct module *mod, unsigned int *size, Elf_Shdr *sechdr,
+		       unsigned int section);
+char *module_flags(struct module *mod, char *buf, bool show_state);
+size_t module_flags_taint(unsigned long taints, char *buf);
+
+static inline void module_assert_mutex_or_preempt(void)
+{
+#ifdef CONFIG_LOCKDEP
+	if (unlikely(!debug_locks))
+		return;
+
+	WARN_ON_ONCE(!rcu_read_lock_sched_held() &&
+		     !lockdep_is_held(&module_mutex));
+#endif
+}
+
+static inline unsigned long kernel_symbol_value(const struct kernel_symbol *sym)
+{
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+	return (unsigned long)offset_to_ptr(&sym->value_offset);
+#else
+	return sym->value;
+#endif
+}
+
+#ifdef CONFIG_LIVEPATCH
+int copy_module_elf(struct module *mod, struct load_info *info);
+void free_module_elf(struct module *mod);
+#else /* !CONFIG_LIVEPATCH */
+static inline int copy_module_elf(struct module *mod, struct load_info *info)
+{
+	return 0;
+}
+
+static inline void free_module_elf(struct module *mod) { }
+#endif /* CONFIG_LIVEPATCH */
+
+static inline bool set_livepatch_module(struct module *mod)
+{
+#ifdef CONFIG_LIVEPATCH
+	mod->klp = true;
+	return true;
+#else
+	return false;
+#endif
+}
+
+#ifdef CONFIG_MODULE_UNLOAD_TAINT_TRACKING
+struct mod_unload_taint {
+	struct list_head list;
+	char name[MODULE_NAME_LEN];
+	unsigned long taints;
+	u64 count;
+};
+
+int try_add_tainted_module(struct module *mod);
+void print_unloaded_tainted_modules(void);
+#else /* !CONFIG_MODULE_UNLOAD_TAINT_TRACKING */
+static inline int try_add_tainted_module(struct module *mod)
+{
+	return 0;
+}
+
+static inline void print_unloaded_tainted_modules(void)
+{
+}
+#endif /* CONFIG_MODULE_UNLOAD_TAINT_TRACKING */
+
+#ifdef CONFIG_MODULE_DECOMPRESS
+int module_decompress(struct load_info *info, const void *buf, size_t size);
+void module_decompress_cleanup(struct load_info *info);
+#else
+static inline int module_decompress(struct load_info *info,
+				    const void *buf, size_t size)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void module_decompress_cleanup(struct load_info *info)
+{
+}
+#endif
+
+struct mod_tree_root {
+#ifdef CONFIG_MODULES_TREE_LOOKUP
+	struct latch_tree_root root;
+#endif
+	unsigned long addr_min;
+	unsigned long addr_max;
+};
+
+extern struct mod_tree_root mod_tree;
+extern struct mod_tree_root mod_data_tree;
+
+#ifdef CONFIG_MODULES_TREE_LOOKUP
+void mod_tree_insert(struct module *mod);
+void mod_tree_remove_init(struct module *mod);
+void mod_tree_remove(struct module *mod);
+struct module *mod_find(unsigned long addr, struct mod_tree_root *tree);
+#else /* !CONFIG_MODULES_TREE_LOOKUP */
+
+static inline void mod_tree_insert(struct module *mod) { }
+static inline void mod_tree_remove_init(struct module *mod) { }
+static inline void mod_tree_remove(struct module *mod) { }
+static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *tree)
+{
+	struct module *mod;
+
+	list_for_each_entry_rcu(mod, &modules, list,
+				lockdep_is_held(&module_mutex)) {
+		if (within_module(addr, mod))
+			return mod;
+	}
+
+	return NULL;
+}
+#endif /* CONFIG_MODULES_TREE_LOOKUP */
+
+void module_enable_ro(const struct module *mod, bool after_init);
+void module_enable_nx(const struct module *mod);
+void module_enable_x(const struct module *mod);
+int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+				char *secstrings, struct module *mod);
+bool module_check_misalignment(const struct module *mod);
+
+#ifdef CONFIG_MODULE_SIG
+int module_sig_check(struct load_info *info, int flags);
+#else /* !CONFIG_MODULE_SIG */
+static inline int module_sig_check(struct load_info *info, int flags)
+{
+	return 0;
+}
+#endif /* !CONFIG_MODULE_SIG */
+
+#ifdef CONFIG_DEBUG_KMEMLEAK
+void kmemleak_load_module(const struct module *mod, const struct load_info *info);
+#else /* !CONFIG_DEBUG_KMEMLEAK */
+static inline void kmemleak_load_module(const struct module *mod,
+					const struct load_info *info) { }
+#endif /* CONFIG_DEBUG_KMEMLEAK */
+
+#ifdef CONFIG_KALLSYMS
+void init_build_id(struct module *mod, const struct load_info *info);
+void layout_symtab(struct module *mod, struct load_info *info);
+void add_kallsyms(struct module *mod, const struct load_info *info);
+unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name);
+
+static inline bool sect_empty(const Elf_Shdr *sect)
+{
+	return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
+}
+#else /* !CONFIG_KALLSYMS */
+static inline void init_build_id(struct module *mod, const struct load_info *info) { }
+static inline void layout_symtab(struct module *mod, struct load_info *info) { }
+static inline void add_kallsyms(struct module *mod, const struct load_info *info) { }
+#endif /* CONFIG_KALLSYMS */
+
+#ifdef CONFIG_SYSFS
+int mod_sysfs_setup(struct module *mod, const struct load_info *info,
+		    struct kernel_param *kparam, unsigned int num_params);
+void mod_sysfs_teardown(struct module *mod);
+void init_param_lock(struct module *mod);
+#else /* !CONFIG_SYSFS */
+static inline int mod_sysfs_setup(struct module *mod,
+			   	  const struct load_info *info,
+			   	  struct kernel_param *kparam,
+			   	  unsigned int num_params)
+{
+	return 0;
+}
+
+static inline void mod_sysfs_teardown(struct module *mod) { }
+static inline void init_param_lock(struct module *mod) { }
+#endif /* CONFIG_SYSFS */
+
+#ifdef CONFIG_MODVERSIONS
+int check_version(const struct load_info *info,
+		  const char *symname, struct module *mod, const s32 *crc);
+void module_layout(struct module *mod, struct modversion_info *ver, struct kernel_param *kp,
+		   struct kernel_symbol *ks, struct tracepoint * const *tp);
+int check_modstruct_version(const struct load_info *info, struct module *mod);
+int same_magic(const char *amagic, const char *bmagic, bool has_crcs);
+#else /* !CONFIG_MODVERSIONS */
+static inline int check_version(const struct load_info *info,
+				const char *symname,
+				struct module *mod,
+				const s32 *crc)
+{
+	return 1;
+}
+
+static inline int check_modstruct_version(const struct load_info *info,
+					  struct module *mod)
+{
+	return 1;
+}
+
+static inline int same_magic(const char *amagic, const char *bmagic, bool has_crcs)
+{
+	return strcmp(amagic, bmagic) == 0;
+}
+#endif /* CONFIG_MODVERSIONS */
diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c
new file mode 100644
index 000000000..4523f99b0
--- /dev/null
+++ b/kernel/module/kallsyms.c
@@ -0,0 +1,532 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module kallsyms support
+ *
+ * Copyright (C) 2010 Rusty Russell
+ */
+
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/buildid.h>
+#include <linux/bsearch.h>
+#include "internal.h"
+
+/* Lookup exported symbol in given range of kernel_symbols */
+static const struct kernel_symbol *lookup_exported_symbol(const char *name,
+							  const struct kernel_symbol *start,
+							  const struct kernel_symbol *stop)
+{
+	return bsearch(name, start, stop - start,
+			sizeof(struct kernel_symbol), cmp_name);
+}
+
+static int is_exported(const char *name, unsigned long value,
+		       const struct module *mod)
+{
+	const struct kernel_symbol *ks;
+
+	if (!mod)
+		ks = lookup_exported_symbol(name, __start___ksymtab, __stop___ksymtab);
+	else
+		ks = lookup_exported_symbol(name, mod->syms, mod->syms + mod->num_syms);
+
+	return ks && kernel_symbol_value(ks) == value;
+}
+
+/* As per nm */
+static char elf_type(const Elf_Sym *sym, const struct load_info *info)
+{
+	const Elf_Shdr *sechdrs = info->sechdrs;
+
+	if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
+		if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT)
+			return 'v';
+		else
+			return 'w';
+	}
+	if (sym->st_shndx == SHN_UNDEF)
+		return 'U';
+	if (sym->st_shndx == SHN_ABS || sym->st_shndx == info->index.pcpu)
+		return 'a';
+	if (sym->st_shndx >= SHN_LORESERVE)
+		return '?';
+	if (sechdrs[sym->st_shndx].sh_flags & SHF_EXECINSTR)
+		return 't';
+	if (sechdrs[sym->st_shndx].sh_flags & SHF_ALLOC &&
+	    sechdrs[sym->st_shndx].sh_type != SHT_NOBITS) {
+		if (!(sechdrs[sym->st_shndx].sh_flags & SHF_WRITE))
+			return 'r';
+		else if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
+			return 'g';
+		else
+			return 'd';
+	}
+	if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
+		if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
+			return 's';
+		else
+			return 'b';
+	}
+	if (strstarts(info->secstrings + sechdrs[sym->st_shndx].sh_name,
+		      ".debug")) {
+		return 'n';
+	}
+	return '?';
+}
+
+static bool is_core_symbol(const Elf_Sym *src, const Elf_Shdr *sechdrs,
+			   unsigned int shnum, unsigned int pcpundx)
+{
+	const Elf_Shdr *sec;
+
+	if (src->st_shndx == SHN_UNDEF ||
+	    src->st_shndx >= shnum ||
+	    !src->st_name)
+		return false;
+
+#ifdef CONFIG_KALLSYMS_ALL
+	if (src->st_shndx == pcpundx)
+		return true;
+#endif
+
+	sec = sechdrs + src->st_shndx;
+	if (!(sec->sh_flags & SHF_ALLOC)
+#ifndef CONFIG_KALLSYMS_ALL
+	    || !(sec->sh_flags & SHF_EXECINSTR)
+#endif
+	    || (sec->sh_entsize & INIT_OFFSET_MASK))
+		return false;
+
+	return true;
+}
+
+/*
+ * We only allocate and copy the strings needed by the parts of symtab
+ * we keep.  This is simple, but has the effect of making multiple
+ * copies of duplicates.  We could be more sophisticated, see
+ * linux-kernel thread starting with
+ * <73defb5e4bca04a6431392cc341112b1@localhost>.
+ */
+void layout_symtab(struct module *mod, struct load_info *info)
+{
+	Elf_Shdr *symsect = info->sechdrs + info->index.sym;
+	Elf_Shdr *strsect = info->sechdrs + info->index.str;
+	const Elf_Sym *src;
+	unsigned int i, nsrc, ndst, strtab_size = 0;
+
+	/* Put symbol section at end of init part of module. */
+	symsect->sh_flags |= SHF_ALLOC;
+	symsect->sh_entsize = module_get_offset(mod, &mod->init_layout.size, symsect,
+						info->index.sym) | INIT_OFFSET_MASK;
+	pr_debug("\t%s\n", info->secstrings + symsect->sh_name);
+
+	src = (void *)info->hdr + symsect->sh_offset;
+	nsrc = symsect->sh_size / sizeof(*src);
+
+	/* Compute total space required for the core symbols' strtab. */
+	for (ndst = i = 0; i < nsrc; i++) {
+		if (i == 0 || is_livepatch_module(mod) ||
+		    is_core_symbol(src + i, info->sechdrs, info->hdr->e_shnum,
+				   info->index.pcpu)) {
+			strtab_size += strlen(&info->strtab[src[i].st_name]) + 1;
+			ndst++;
+		}
+	}
+
+	/* Append room for core symbols at end of core part. */
+	info->symoffs = ALIGN(mod->data_layout.size, symsect->sh_addralign ?: 1);
+	info->stroffs = mod->data_layout.size = info->symoffs + ndst * sizeof(Elf_Sym);
+	mod->data_layout.size += strtab_size;
+	/* Note add_kallsyms() computes strtab_size as core_typeoffs - stroffs */
+	info->core_typeoffs = mod->data_layout.size;
+	mod->data_layout.size += ndst * sizeof(char);
+	mod->data_layout.size = strict_align(mod->data_layout.size);
+
+	/* Put string table section at end of init part of module. */
+	strsect->sh_flags |= SHF_ALLOC;
+	strsect->sh_entsize = module_get_offset(mod, &mod->init_layout.size, strsect,
+						info->index.str) | INIT_OFFSET_MASK;
+	pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
+
+	/* We'll tack temporary mod_kallsyms on the end. */
+	mod->init_layout.size = ALIGN(mod->init_layout.size,
+				      __alignof__(struct mod_kallsyms));
+	info->mod_kallsyms_init_off = mod->init_layout.size;
+	mod->init_layout.size += sizeof(struct mod_kallsyms);
+	info->init_typeoffs = mod->init_layout.size;
+	mod->init_layout.size += nsrc * sizeof(char);
+	mod->init_layout.size = strict_align(mod->init_layout.size);
+}
+
+/*
+ * We use the full symtab and strtab which layout_symtab arranged to
+ * be appended to the init section.  Later we switch to the cut-down
+ * core-only ones.
+ */
+void add_kallsyms(struct module *mod, const struct load_info *info)
+{
+	unsigned int i, ndst;
+	const Elf_Sym *src;
+	Elf_Sym *dst;
+	char *s;
+	Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
+	unsigned long strtab_size;
+
+	/* Set up to point into init section. */
+	mod->kallsyms = (void __rcu *)mod->init_layout.base +
+		info->mod_kallsyms_init_off;
+
+	rcu_read_lock();
+	/* The following is safe since this pointer cannot change */
+	rcu_dereference(mod->kallsyms)->symtab = (void *)symsec->sh_addr;
+	rcu_dereference(mod->kallsyms)->num_symtab = symsec->sh_size / sizeof(Elf_Sym);
+	/* Make sure we get permanent strtab: don't use info->strtab. */
+	rcu_dereference(mod->kallsyms)->strtab =
+		(void *)info->sechdrs[info->index.str].sh_addr;
+	rcu_dereference(mod->kallsyms)->typetab = mod->init_layout.base + info->init_typeoffs;
+
+	/*
+	 * Now populate the cut down core kallsyms for after init
+	 * and set types up while we still have access to sections.
+	 */
+	mod->core_kallsyms.symtab = dst = mod->data_layout.base + info->symoffs;
+	mod->core_kallsyms.strtab = s = mod->data_layout.base + info->stroffs;
+	mod->core_kallsyms.typetab = mod->data_layout.base + info->core_typeoffs;
+	strtab_size = info->core_typeoffs - info->stroffs;
+	src = rcu_dereference(mod->kallsyms)->symtab;
+	for (ndst = i = 0; i < rcu_dereference(mod->kallsyms)->num_symtab; i++) {
+		rcu_dereference(mod->kallsyms)->typetab[i] = elf_type(src + i, info);
+		if (i == 0 || is_livepatch_module(mod) ||
+		    is_core_symbol(src + i, info->sechdrs, info->hdr->e_shnum,
+				   info->index.pcpu)) {
+			ssize_t ret;
+
+			mod->core_kallsyms.typetab[ndst] =
+			    rcu_dereference(mod->kallsyms)->typetab[i];
+			dst[ndst] = src[i];
+			dst[ndst++].st_name = s - mod->core_kallsyms.strtab;
+			ret = strscpy(s,
+				      &rcu_dereference(mod->kallsyms)->strtab[src[i].st_name],
+				      strtab_size);
+			if (ret < 0)
+				break;
+			s += ret + 1;
+			strtab_size -= ret + 1;
+		}
+	}
+	rcu_read_unlock();
+	mod->core_kallsyms.num_symtab = ndst;
+}
+
+#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
+void init_build_id(struct module *mod, const struct load_info *info)
+{
+	const Elf_Shdr *sechdr;
+	unsigned int i;
+
+	for (i = 0; i < info->hdr->e_shnum; i++) {
+		sechdr = &info->sechdrs[i];
+		if (!sect_empty(sechdr) && sechdr->sh_type == SHT_NOTE &&
+		    !build_id_parse_buf((void *)sechdr->sh_addr, mod->build_id,
+					sechdr->sh_size))
+			break;
+	}
+}
+#else
+void init_build_id(struct module *mod, const struct load_info *info)
+{
+}
+#endif
+
+/*
+ * This ignores the intensely annoying "mapping symbols" found
+ * in ARM ELF files: $a, $t and $d.
+ */
+static inline int is_arm_mapping_symbol(const char *str)
+{
+	if (str[0] == '.' && str[1] == 'L')
+		return true;
+	return str[0] == '$' && strchr("axtd", str[1]) &&
+	       (str[2] == '\0' || str[2] == '.');
+}
+
+static const char *kallsyms_symbol_name(struct mod_kallsyms *kallsyms, unsigned int symnum)
+{
+	return kallsyms->strtab + kallsyms->symtab[symnum].st_name;
+}
+
+/*
+ * Given a module and address, find the corresponding symbol and return its name
+ * while providing its size and offset if needed.
+ */
+static const char *find_kallsyms_symbol(struct module *mod,
+					unsigned long addr,
+					unsigned long *size,
+					unsigned long *offset)
+{
+	unsigned int i, best = 0;
+	unsigned long nextval, bestval;
+	struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
+
+	/* At worse, next value is at end of module */
+	if (within_module_init(addr, mod))
+		nextval = (unsigned long)mod->init_layout.base + mod->init_layout.text_size;
+	else
+		nextval = (unsigned long)mod->core_layout.base + mod->core_layout.text_size;
+
+	bestval = kallsyms_symbol_value(&kallsyms->symtab[best]);
+
+	/*
+	 * Scan for closest preceding symbol, and next symbol. (ELF
+	 * starts real symbols at 1).
+	 */
+	for (i = 1; i < kallsyms->num_symtab; i++) {
+		const Elf_Sym *sym = &kallsyms->symtab[i];
+		unsigned long thisval = kallsyms_symbol_value(sym);
+
+		if (sym->st_shndx == SHN_UNDEF)
+			continue;
+
+		/*
+		 * We ignore unnamed symbols: they're uninformative
+		 * and inserted at a whim.
+		 */
+		if (*kallsyms_symbol_name(kallsyms, i) == '\0' ||
+		    is_arm_mapping_symbol(kallsyms_symbol_name(kallsyms, i)))
+			continue;
+
+		if (thisval <= addr && thisval > bestval) {
+			best = i;
+			bestval = thisval;
+		}
+		if (thisval > addr && thisval < nextval)
+			nextval = thisval;
+	}
+
+	if (!best)
+		return NULL;
+
+	if (size)
+		*size = nextval - bestval;
+	if (offset)
+		*offset = addr - bestval;
+
+	return kallsyms_symbol_name(kallsyms, best);
+}
+
+void * __weak dereference_module_function_descriptor(struct module *mod,
+						     void *ptr)
+{
+	return ptr;
+}
+
+/*
+ * For kallsyms to ask for address resolution.  NULL means not found.  Careful
+ * not to lock to avoid deadlock on oopses, simply disable preemption.
+ */
+const char *module_address_lookup(unsigned long addr,
+				  unsigned long *size,
+			    unsigned long *offset,
+			    char **modname,
+			    const unsigned char **modbuildid,
+			    char *namebuf)
+{
+	const char *ret = NULL;
+	struct module *mod;
+
+	preempt_disable();
+	mod = __module_address(addr);
+	if (mod) {
+		if (modname)
+			*modname = mod->name;
+		if (modbuildid) {
+#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
+			*modbuildid = mod->build_id;
+#else
+			*modbuildid = NULL;
+#endif
+		}
+
+		ret = find_kallsyms_symbol(mod, addr, size, offset);
+	}
+	/* Make a copy in here where it's safe */
+	if (ret) {
+		strncpy(namebuf, ret, KSYM_NAME_LEN - 1);
+		ret = namebuf;
+	}
+	preempt_enable();
+
+	return ret;
+}
+
+int lookup_module_symbol_name(unsigned long addr, char *symname)
+{
+	struct module *mod;
+
+	preempt_disable();
+	list_for_each_entry_rcu(mod, &modules, list) {
+		if (mod->state == MODULE_STATE_UNFORMED)
+			continue;
+		if (within_module(addr, mod)) {
+			const char *sym;
+
+			sym = find_kallsyms_symbol(mod, addr, NULL, NULL);
+			if (!sym)
+				goto out;
+
+			strscpy(symname, sym, KSYM_NAME_LEN);
+			preempt_enable();
+			return 0;
+		}
+	}
+out:
+	preempt_enable();
+	return -ERANGE;
+}
+
+int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
+			       unsigned long *offset, char *modname, char *name)
+{
+	struct module *mod;
+
+	preempt_disable();
+	list_for_each_entry_rcu(mod, &modules, list) {
+		if (mod->state == MODULE_STATE_UNFORMED)
+			continue;
+		if (within_module(addr, mod)) {
+			const char *sym;
+
+			sym = find_kallsyms_symbol(mod, addr, size, offset);
+			if (!sym)
+				goto out;
+			if (modname)
+				strscpy(modname, mod->name, MODULE_NAME_LEN);
+			if (name)
+				strscpy(name, sym, KSYM_NAME_LEN);
+			preempt_enable();
+			return 0;
+		}
+	}
+out:
+	preempt_enable();
+	return -ERANGE;
+}
+
+int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
+		       char *name, char *module_name, int *exported)
+{
+	struct module *mod;
+
+	preempt_disable();
+	list_for_each_entry_rcu(mod, &modules, list) {
+		struct mod_kallsyms *kallsyms;
+
+		if (mod->state == MODULE_STATE_UNFORMED)
+			continue;
+		kallsyms = rcu_dereference_sched(mod->kallsyms);
+		if (symnum < kallsyms->num_symtab) {
+			const Elf_Sym *sym = &kallsyms->symtab[symnum];
+
+			*value = kallsyms_symbol_value(sym);
+			*type = kallsyms->typetab[symnum];
+			strscpy(name, kallsyms_symbol_name(kallsyms, symnum), KSYM_NAME_LEN);
+			strscpy(module_name, mod->name, MODULE_NAME_LEN);
+			*exported = is_exported(name, *value, mod);
+			preempt_enable();
+			return 0;
+		}
+		symnum -= kallsyms->num_symtab;
+	}
+	preempt_enable();
+	return -ERANGE;
+}
+
+/* Given a module and name of symbol, find and return the symbol's value */
+unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name)
+{
+	unsigned int i;
+	struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
+
+	for (i = 0; i < kallsyms->num_symtab; i++) {
+		const Elf_Sym *sym = &kallsyms->symtab[i];
+
+		if (strcmp(name, kallsyms_symbol_name(kallsyms, i)) == 0 &&
+		    sym->st_shndx != SHN_UNDEF)
+			return kallsyms_symbol_value(sym);
+	}
+	return 0;
+}
+
+static unsigned long __module_kallsyms_lookup_name(const char *name)
+{
+	struct module *mod;
+	char *colon;
+
+	colon = strnchr(name, MODULE_NAME_LEN, ':');
+	if (colon) {
+		mod = find_module_all(name, colon - name, false);
+		if (mod)
+			return find_kallsyms_symbol_value(mod, colon + 1);
+		return 0;
+	}
+
+	list_for_each_entry_rcu(mod, &modules, list) {
+		unsigned long ret;
+
+		if (mod->state == MODULE_STATE_UNFORMED)
+			continue;
+		ret = find_kallsyms_symbol_value(mod, name);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+/* Look for this name: can be of form module:name. */
+unsigned long module_kallsyms_lookup_name(const char *name)
+{
+	unsigned long ret;
+
+	/* Don't lock: we're in enough trouble already. */
+	preempt_disable();
+	ret = __module_kallsyms_lookup_name(name);
+	preempt_enable();
+	return ret;
+}
+
+int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
+					     struct module *, unsigned long),
+				   void *data)
+{
+	struct module *mod;
+	unsigned int i;
+	int ret = 0;
+
+	mutex_lock(&module_mutex);
+	list_for_each_entry(mod, &modules, list) {
+		struct mod_kallsyms *kallsyms;
+
+		if (mod->state == MODULE_STATE_UNFORMED)
+			continue;
+
+		/* Use rcu_dereference_sched() to remain compliant with the sparse tool */
+		preempt_disable();
+		kallsyms = rcu_dereference_sched(mod->kallsyms);
+		preempt_enable();
+
+		for (i = 0; i < kallsyms->num_symtab; i++) {
+			const Elf_Sym *sym = &kallsyms->symtab[i];
+
+			if (sym->st_shndx == SHN_UNDEF)
+				continue;
+
+			ret = fn(data, kallsyms_symbol_name(kallsyms, i),
+				 mod, kallsyms_symbol_value(sym));
+			if (ret != 0)
+				goto out;
+		}
+	}
+out:
+	mutex_unlock(&module_mutex);
+	return ret;
+}
diff --git a/kernel/module/kdb.c b/kernel/module/kdb.c
new file mode 100644
index 000000000..f4317f92e
--- /dev/null
+++ b/kernel/module/kdb.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module kdb support
+ *
+ * Copyright (C) 2010 Jason Wessel
+ */
+
+#include <linux/module.h>
+#include <linux/kdb.h>
+#include "internal.h"
+
+/*
+ * kdb_lsmod - This function implements the 'lsmod' command.  Lists
+ *	currently loaded kernel modules.
+ *	Mostly taken from userland lsmod.
+ */
+int kdb_lsmod(int argc, const char **argv)
+{
+	struct module *mod;
+
+	if (argc != 0)
+		return KDB_ARGCOUNT;
+
+	kdb_printf("Module                  Size  modstruct     Used by\n");
+	list_for_each_entry(mod, &modules, list) {
+		if (mod->state == MODULE_STATE_UNFORMED)
+			continue;
+
+		kdb_printf("%-20s%8u", mod->name, mod->core_layout.size);
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+		kdb_printf("/%8u", mod->data_layout.size);
+#endif
+		kdb_printf("  0x%px ", (void *)mod);
+#ifdef CONFIG_MODULE_UNLOAD
+		kdb_printf("%4d ", module_refcount(mod));
+#endif
+		if (mod->state == MODULE_STATE_GOING)
+			kdb_printf(" (Unloading)");
+		else if (mod->state == MODULE_STATE_COMING)
+			kdb_printf(" (Loading)");
+		else
+			kdb_printf(" (Live)");
+		kdb_printf(" 0x%px", mod->core_layout.base);
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+		kdb_printf("/0x%px", mod->data_layout.base);
+#endif
+
+#ifdef CONFIG_MODULE_UNLOAD
+		{
+			struct module_use *use;
+
+			kdb_printf(" [ ");
+			list_for_each_entry(use, &mod->source_list,
+					    source_list)
+				kdb_printf("%s ", use->target->name);
+			kdb_printf("]\n");
+		}
+#endif
+	}
+
+	return 0;
+}
diff --git a/kernel/module/livepatch.c b/kernel/module/livepatch.c
new file mode 100644
index 000000000..486d4ff92
--- /dev/null
+++ b/kernel/module/livepatch.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module livepatch support
+ *
+ * Copyright (C) 2016 Jessica Yu <jeyu@redhat.com>
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+/*
+ * Persist Elf information about a module. Copy the Elf header,
+ * section header table, section string table, and symtab section
+ * index from info to mod->klp_info.
+ */
+int copy_module_elf(struct module *mod, struct load_info *info)
+{
+	unsigned int size, symndx;
+	int ret;
+
+	size = sizeof(*mod->klp_info);
+	mod->klp_info = kmalloc(size, GFP_KERNEL);
+	if (!mod->klp_info)
+		return -ENOMEM;
+
+	/* Elf header */
+	size = sizeof(mod->klp_info->hdr);
+	memcpy(&mod->klp_info->hdr, info->hdr, size);
+
+	/* Elf section header table */
+	size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
+	mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
+	if (!mod->klp_info->sechdrs) {
+		ret = -ENOMEM;
+		goto free_info;
+	}
+
+	/* Elf section name string table */
+	size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
+	mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
+	if (!mod->klp_info->secstrings) {
+		ret = -ENOMEM;
+		goto free_sechdrs;
+	}
+
+	/* Elf symbol section index */
+	symndx = info->index.sym;
+	mod->klp_info->symndx = symndx;
+
+	/*
+	 * For livepatch modules, core_kallsyms.symtab is a complete
+	 * copy of the original symbol table. Adjust sh_addr to point
+	 * to core_kallsyms.symtab since the copy of the symtab in module
+	 * init memory is freed at the end of do_init_module().
+	 */
+	mod->klp_info->sechdrs[symndx].sh_addr = (unsigned long)mod->core_kallsyms.symtab;
+
+	return 0;
+
+free_sechdrs:
+	kfree(mod->klp_info->sechdrs);
+free_info:
+	kfree(mod->klp_info);
+	return ret;
+}
+
+void free_module_elf(struct module *mod)
+{
+	kfree(mod->klp_info->sechdrs);
+	kfree(mod->klp_info->secstrings);
+	kfree(mod->klp_info);
+}
diff --git a/kernel/module/main.c b/kernel/module/main.c
new file mode 100644
index 000000000..7a376e26d
--- /dev/null
+++ b/kernel/module/main.c
@@ -0,0 +1,3144 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2002 Richard Henderson
+ * Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
+ */
+
+#define INCLUDE_VERMAGIC
+
+#include <linux/export.h>
+#include <linux/extable.h>
+#include <linux/moduleloader.h>
+#include <linux/module_signature.h>
+#include <linux/trace_events.h>
+#include <linux/init.h>
+#include <linux/kallsyms.h>
+#include <linux/buildid.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/kernel_read_file.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/elf.h>
+#include <linux/seq_file.h>
+#include <linux/syscalls.h>
+#include <linux/fcntl.h>
+#include <linux/rcupdate.h>
+#include <linux/capability.h>
+#include <linux/cpu.h>
+#include <linux/moduleparam.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/vermagic.h>
+#include <linux/notifier.h>
+#include <linux/sched.h>
+#include <linux/device.h>
+#include <linux/string.h>
+#include <linux/mutex.h>
+#include <linux/rculist.h>
+#include <linux/uaccess.h>
+#include <asm/cacheflush.h>
+#include <linux/set_memory.h>
+#include <asm/mmu_context.h>
+#include <linux/license.h>
+#include <asm/sections.h>
+#include <linux/tracepoint.h>
+#include <linux/ftrace.h>
+#include <linux/livepatch.h>
+#include <linux/async.h>
+#include <linux/percpu.h>
+#include <linux/kmemleak.h>
+#include <linux/jump_label.h>
+#include <linux/pfn.h>
+#include <linux/bsearch.h>
+#include <linux/dynamic_debug.h>
+#include <linux/audit.h>
+#include <linux/cfi.h>
+#include <uapi/linux/module.h>
+#include "internal.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/module.h>
+
+/*
+ * Mutex protects:
+ * 1) List of modules (also safely readable with preempt_disable),
+ * 2) module_use links,
+ * 3) mod_tree.addr_min/mod_tree.addr_max.
+ * (delete and add uses RCU list operations).
+ */
+DEFINE_MUTEX(module_mutex);
+LIST_HEAD(modules);
+
+/* Work queue for freeing init sections in success case */
+static void do_free_init(struct work_struct *w);
+static DECLARE_WORK(init_free_wq, do_free_init);
+static LLIST_HEAD(init_free_list);
+
+struct mod_tree_root mod_tree __cacheline_aligned = {
+	.addr_min = -1UL,
+};
+
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+struct mod_tree_root mod_data_tree __cacheline_aligned = {
+	.addr_min = -1UL,
+};
+#endif
+
+#define module_addr_min mod_tree.addr_min
+#define module_addr_max mod_tree.addr_max
+
+struct symsearch {
+	const struct kernel_symbol *start, *stop;
+	const s32 *crcs;
+	enum mod_license license;
+};
+
+/*
+ * Bounds of module text, for speeding up __module_address.
+ * Protected by module_mutex.
+ */
+static void __mod_update_bounds(void *base, unsigned int size, struct mod_tree_root *tree)
+{
+	unsigned long min = (unsigned long)base;
+	unsigned long max = min + size;
+
+	if (min < tree->addr_min)
+		tree->addr_min = min;
+	if (max > tree->addr_max)
+		tree->addr_max = max;
+}
+
+static void mod_update_bounds(struct module *mod)
+{
+	__mod_update_bounds(mod->core_layout.base, mod->core_layout.size, &mod_tree);
+	if (mod->init_layout.size)
+		__mod_update_bounds(mod->init_layout.base, mod->init_layout.size, &mod_tree);
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+	__mod_update_bounds(mod->data_layout.base, mod->data_layout.size, &mod_data_tree);
+#endif
+}
+
+/* Block module loading/unloading? */
+int modules_disabled;
+core_param(nomodule, modules_disabled, bint, 0);
+
+/* Waiting for a module to finish initializing? */
+static DECLARE_WAIT_QUEUE_HEAD(module_wq);
+
+static BLOCKING_NOTIFIER_HEAD(module_notify_list);
+
+int register_module_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&module_notify_list, nb);
+}
+EXPORT_SYMBOL(register_module_notifier);
+
+int unregister_module_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&module_notify_list, nb);
+}
+EXPORT_SYMBOL(unregister_module_notifier);
+
+/*
+ * We require a truly strong try_module_get(): 0 means success.
+ * Otherwise an error is returned due to ongoing or failed
+ * initialization etc.
+ */
+static inline int strong_try_module_get(struct module *mod)
+{
+	BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
+	if (mod && mod->state == MODULE_STATE_COMING)
+		return -EBUSY;
+	if (try_module_get(mod))
+		return 0;
+	else
+		return -ENOENT;
+}
+
+static inline void add_taint_module(struct module *mod, unsigned flag,
+				    enum lockdep_ok lockdep_ok)
+{
+	add_taint(flag, lockdep_ok);
+	set_bit(flag, &mod->taints);
+}
+
+/*
+ * A thread that wants to hold a reference to a module only while it
+ * is running can call this to safely exit.
+ */
+void __noreturn __module_put_and_kthread_exit(struct module *mod, long code)
+{
+	module_put(mod);
+	kthread_exit(code);
+}
+EXPORT_SYMBOL(__module_put_and_kthread_exit);
+
+/* Find a module section: 0 means not found. */
+static unsigned int find_sec(const struct load_info *info, const char *name)
+{
+	unsigned int i;
+
+	for (i = 1; i < info->hdr->e_shnum; i++) {
+		Elf_Shdr *shdr = &info->sechdrs[i];
+		/* Alloc bit cleared means "ignore it." */
+		if ((shdr->sh_flags & SHF_ALLOC)
+		    && strcmp(info->secstrings + shdr->sh_name, name) == 0)
+			return i;
+	}
+	return 0;
+}
+
+/* Find a module section, or NULL. */
+static void *section_addr(const struct load_info *info, const char *name)
+{
+	/* Section 0 has sh_addr 0. */
+	return (void *)info->sechdrs[find_sec(info, name)].sh_addr;
+}
+
+/* Find a module section, or NULL.  Fill in number of "objects" in section. */
+static void *section_objs(const struct load_info *info,
+			  const char *name,
+			  size_t object_size,
+			  unsigned int *num)
+{
+	unsigned int sec = find_sec(info, name);
+
+	/* Section 0 has sh_addr 0 and sh_size 0. */
+	*num = info->sechdrs[sec].sh_size / object_size;
+	return (void *)info->sechdrs[sec].sh_addr;
+}
+
+/* Find a module section: 0 means not found. Ignores SHF_ALLOC flag. */
+static unsigned int find_any_sec(const struct load_info *info, const char *name)
+{
+	unsigned int i;
+
+	for (i = 1; i < info->hdr->e_shnum; i++) {
+		Elf_Shdr *shdr = &info->sechdrs[i];
+		if (strcmp(info->secstrings + shdr->sh_name, name) == 0)
+			return i;
+	}
+	return 0;
+}
+
+/*
+ * Find a module section, or NULL. Fill in number of "objects" in section.
+ * Ignores SHF_ALLOC flag.
+ */
+static __maybe_unused void *any_section_objs(const struct load_info *info,
+					     const char *name,
+					     size_t object_size,
+					     unsigned int *num)
+{
+	unsigned int sec = find_any_sec(info, name);
+
+	/* Section 0 has sh_addr 0 and sh_size 0. */
+	*num = info->sechdrs[sec].sh_size / object_size;
+	return (void *)info->sechdrs[sec].sh_addr;
+}
+
+#ifndef CONFIG_MODVERSIONS
+#define symversion(base, idx) NULL
+#else
+#define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
+#endif
+
+static const char *kernel_symbol_name(const struct kernel_symbol *sym)
+{
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+	return offset_to_ptr(&sym->name_offset);
+#else
+	return sym->name;
+#endif
+}
+
+static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
+{
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+	if (!sym->namespace_offset)
+		return NULL;
+	return offset_to_ptr(&sym->namespace_offset);
+#else
+	return sym->namespace;
+#endif
+}
+
+int cmp_name(const void *name, const void *sym)
+{
+	return strcmp(name, kernel_symbol_name(sym));
+}
+
+static bool find_exported_symbol_in_section(const struct symsearch *syms,
+					    struct module *owner,
+					    struct find_symbol_arg *fsa)
+{
+	struct kernel_symbol *sym;
+
+	if (!fsa->gplok && syms->license == GPL_ONLY)
+		return false;
+
+	sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
+			sizeof(struct kernel_symbol), cmp_name);
+	if (!sym)
+		return false;
+
+	fsa->owner = owner;
+	fsa->crc = symversion(syms->crcs, sym - syms->start);
+	fsa->sym = sym;
+	fsa->license = syms->license;
+
+	return true;
+}
+
+/*
+ * Find an exported symbol and return it, along with, (optional) crc and
+ * (optional) module which owns it.  Needs preempt disabled or module_mutex.
+ */
+bool find_symbol(struct find_symbol_arg *fsa)
+{
+	static const struct symsearch arr[] = {
+		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
+		  NOT_GPL_ONLY },
+		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
+		  __start___kcrctab_gpl,
+		  GPL_ONLY },
+	};
+	struct module *mod;
+	unsigned int i;
+
+	module_assert_mutex_or_preempt();
+
+	for (i = 0; i < ARRAY_SIZE(arr); i++)
+		if (find_exported_symbol_in_section(&arr[i], NULL, fsa))
+			return true;
+
+	list_for_each_entry_rcu(mod, &modules, list,
+				lockdep_is_held(&module_mutex)) {
+		struct symsearch arr[] = {
+			{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
+			  NOT_GPL_ONLY },
+			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
+			  mod->gpl_crcs,
+			  GPL_ONLY },
+		};
+
+		if (mod->state == MODULE_STATE_UNFORMED)
+			continue;
+
+		for (i = 0; i < ARRAY_SIZE(arr); i++)
+			if (find_exported_symbol_in_section(&arr[i], mod, fsa))
+				return true;
+	}
+
+	pr_debug("Failed to find symbol %s\n", fsa->name);
+	return false;
+}
+
+/*
+ * Search for module by name: must hold module_mutex (or preempt disabled
+ * for read-only access).
+ */
+struct module *find_module_all(const char *name, size_t len,
+			       bool even_unformed)
+{
+	struct module *mod;
+
+	module_assert_mutex_or_preempt();
+
+	list_for_each_entry_rcu(mod, &modules, list,
+				lockdep_is_held(&module_mutex)) {
+		if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
+			continue;
+		if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
+			return mod;
+	}
+	return NULL;
+}
+
+struct module *find_module(const char *name)
+{
+	return find_module_all(name, strlen(name), false);
+}
+
+#ifdef CONFIG_SMP
+
+static inline void __percpu *mod_percpu(struct module *mod)
+{
+	return mod->percpu;
+}
+
+static int percpu_modalloc(struct module *mod, struct load_info *info)
+{
+	Elf_Shdr *pcpusec = &info->sechdrs[info->index.pcpu];
+	unsigned long align = pcpusec->sh_addralign;
+
+	if (!pcpusec->sh_size)
+		return 0;
+
+	if (align > PAGE_SIZE) {
+		pr_warn("%s: per-cpu alignment %li > %li\n",
+			mod->name, align, PAGE_SIZE);
+		align = PAGE_SIZE;
+	}
+
+	mod->percpu = __alloc_reserved_percpu(pcpusec->sh_size, align);
+	if (!mod->percpu) {
+		pr_warn("%s: Could not allocate %lu bytes percpu data\n",
+			mod->name, (unsigned long)pcpusec->sh_size);
+		return -ENOMEM;
+	}
+	mod->percpu_size = pcpusec->sh_size;
+	return 0;
+}
+
+static void percpu_modfree(struct module *mod)
+{
+	free_percpu(mod->percpu);
+}
+
+static unsigned int find_pcpusec(struct load_info *info)
+{
+	return find_sec(info, ".data..percpu");
+}
+
+static void percpu_modcopy(struct module *mod,
+			   const void *from, unsigned long size)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
+}
+
+bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
+{
+	struct module *mod;
+	unsigned int cpu;
+
+	preempt_disable();
+
+	list_for_each_entry_rcu(mod, &modules, list) {
+		if (mod->state == MODULE_STATE_UNFORMED)
+			continue;
+		if (!mod->percpu_size)
+			continue;
+		for_each_possible_cpu(cpu) {
+			void *start = per_cpu_ptr(mod->percpu, cpu);
+			void *va = (void *)addr;
+
+			if (va >= start && va < start + mod->percpu_size) {
+				if (can_addr) {
+					*can_addr = (unsigned long) (va - start);
+					*can_addr += (unsigned long)
+						per_cpu_ptr(mod->percpu,
+							    get_boot_cpu_id());
+				}
+				preempt_enable();
+				return true;
+			}
+		}
+	}
+
+	preempt_enable();
+	return false;
+}
+
+/**
+ * is_module_percpu_address() - test whether address is from module static percpu
+ * @addr: address to test
+ *
+ * Test whether @addr belongs to module static percpu area.
+ *
+ * Return: %true if @addr is from module static percpu area
+ */
+bool is_module_percpu_address(unsigned long addr)
+{
+	return __is_module_percpu_address(addr, NULL);
+}
+
+#else /* ... !CONFIG_SMP */
+
+static inline void __percpu *mod_percpu(struct module *mod)
+{
+	return NULL;
+}
+static int percpu_modalloc(struct module *mod, struct load_info *info)
+{
+	/* UP modules shouldn't have this section: ENOMEM isn't quite right */
+	if (info->sechdrs[info->index.pcpu].sh_size != 0)
+		return -ENOMEM;
+	return 0;
+}
+static inline void percpu_modfree(struct module *mod)
+{
+}
+static unsigned int find_pcpusec(struct load_info *info)
+{
+	return 0;
+}
+static inline void percpu_modcopy(struct module *mod,
+				  const void *from, unsigned long size)
+{
+	/* pcpusec should be 0, and size of that section should be 0. */
+	BUG_ON(size != 0);
+}
+bool is_module_percpu_address(unsigned long addr)
+{
+	return false;
+}
+
+bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
+{
+	return false;
+}
+
+#endif /* CONFIG_SMP */
+
+#define MODINFO_ATTR(field)	\
+static void setup_modinfo_##field(struct module *mod, const char *s)  \
+{                                                                     \
+	mod->field = kstrdup(s, GFP_KERNEL);                          \
+}                                                                     \
+static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
+			struct module_kobject *mk, char *buffer)      \
+{                                                                     \
+	return scnprintf(buffer, PAGE_SIZE, "%s\n", mk->mod->field);  \
+}                                                                     \
+static int modinfo_##field##_exists(struct module *mod)               \
+{                                                                     \
+	return mod->field != NULL;                                    \
+}                                                                     \
+static void free_modinfo_##field(struct module *mod)                  \
+{                                                                     \
+	kfree(mod->field);                                            \
+	mod->field = NULL;                                            \
+}                                                                     \
+static struct module_attribute modinfo_##field = {                    \
+	.attr = { .name = __stringify(field), .mode = 0444 },         \
+	.show = show_modinfo_##field,                                 \
+	.setup = setup_modinfo_##field,                               \
+	.test = modinfo_##field##_exists,                             \
+	.free = free_modinfo_##field,                                 \
+};
+
+MODINFO_ATTR(version);
+MODINFO_ATTR(srcversion);
+
+static struct {
+	char name[MODULE_NAME_LEN + 1];
+	char taints[MODULE_FLAGS_BUF_SIZE];
+} last_unloaded_module;
+
+#ifdef CONFIG_MODULE_UNLOAD
+
+EXPORT_TRACEPOINT_SYMBOL(module_get);
+
+/* MODULE_REF_BASE is the base reference count by kmodule loader. */
+#define MODULE_REF_BASE	1
+
+/* Init the unload section of the module. */
+static int module_unload_init(struct module *mod)
+{
+	/*
+	 * Initialize reference counter to MODULE_REF_BASE.
+	 * refcnt == 0 means module is going.
+	 */
+	atomic_set(&mod->refcnt, MODULE_REF_BASE);
+
+	INIT_LIST_HEAD(&mod->source_list);
+	INIT_LIST_HEAD(&mod->target_list);
+
+	/* Hold reference count during initialization. */
+	atomic_inc(&mod->refcnt);
+
+	return 0;
+}
+
+/* Does a already use b? */
+static int already_uses(struct module *a, struct module *b)
+{
+	struct module_use *use;
+
+	list_for_each_entry(use, &b->source_list, source_list) {
+		if (use->source == a) {
+			pr_debug("%s uses %s!\n", a->name, b->name);
+			return 1;
+		}
+	}
+	pr_debug("%s does not use %s!\n", a->name, b->name);
+	return 0;
+}
+
+/*
+ * Module a uses b
+ *  - we add 'a' as a "source", 'b' as a "target" of module use
+ *  - the module_use is added to the list of 'b' sources (so
+ *    'b' can walk the list to see who sourced them), and of 'a'
+ *    targets (so 'a' can see what modules it targets).
+ */
+static int add_module_usage(struct module *a, struct module *b)
+{
+	struct module_use *use;
+
+	pr_debug("Allocating new usage for %s.\n", a->name);
+	use = kmalloc(sizeof(*use), GFP_ATOMIC);
+	if (!use)
+		return -ENOMEM;
+
+	use->source = a;
+	use->target = b;
+	list_add(&use->source_list, &b->source_list);
+	list_add(&use->target_list, &a->target_list);
+	return 0;
+}
+
+/* Module a uses b: caller needs module_mutex() */
+static int ref_module(struct module *a, struct module *b)
+{
+	int err;
+
+	if (b == NULL || already_uses(a, b))
+		return 0;
+
+	/* If module isn't available, we fail. */
+	err = strong_try_module_get(b);
+	if (err)
+		return err;
+
+	err = add_module_usage(a, b);
+	if (err) {
+		module_put(b);
+		return err;
+	}
+	return 0;
+}
+
+/* Clear the unload stuff of the module. */
+static void module_unload_free(struct module *mod)
+{
+	struct module_use *use, *tmp;
+
+	mutex_lock(&module_mutex);
+	list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
+		struct module *i = use->target;
+		pr_debug("%s unusing %s\n", mod->name, i->name);
+		module_put(i);
+		list_del(&use->source_list);
+		list_del(&use->target_list);
+		kfree(use);
+	}
+	mutex_unlock(&module_mutex);
+}
+
+#ifdef CONFIG_MODULE_FORCE_UNLOAD
+static inline int try_force_unload(unsigned int flags)
+{
+	int ret = (flags & O_TRUNC);
+	if (ret)
+		add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE);
+	return ret;
+}
+#else
+static inline int try_force_unload(unsigned int flags)
+{
+	return 0;
+}
+#endif /* CONFIG_MODULE_FORCE_UNLOAD */
+
+/* Try to release refcount of module, 0 means success. */
+static int try_release_module_ref(struct module *mod)
+{
+	int ret;
+
+	/* Try to decrement refcnt which we set at loading */
+	ret = atomic_sub_return(MODULE_REF_BASE, &mod->refcnt);
+	BUG_ON(ret < 0);
+	if (ret)
+		/* Someone can put this right now, recover with checking */
+		ret = atomic_add_unless(&mod->refcnt, MODULE_REF_BASE, 0);
+
+	return ret;
+}
+
+static int try_stop_module(struct module *mod, int flags, int *forced)
+{
+	/* If it's not unused, quit unless we're forcing. */
+	if (try_release_module_ref(mod) != 0) {
+		*forced = try_force_unload(flags);
+		if (!(*forced))
+			return -EWOULDBLOCK;
+	}
+
+	/* Mark it as dying. */
+	mod->state = MODULE_STATE_GOING;
+
+	return 0;
+}
+
+/**
+ * module_refcount() - return the refcount or -1 if unloading
+ * @mod:	the module we're checking
+ *
+ * Return:
+ *	-1 if the module is in the process of unloading
+ *	otherwise the number of references in the kernel to the module
+ */
+int module_refcount(struct module *mod)
+{
+	return atomic_read(&mod->refcnt) - MODULE_REF_BASE;
+}
+EXPORT_SYMBOL(module_refcount);
+
+/* This exists whether we can unload or not */
+static void free_module(struct module *mod);
+
+SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
+		unsigned int, flags)
+{
+	struct module *mod;
+	char name[MODULE_NAME_LEN];
+	char buf[MODULE_FLAGS_BUF_SIZE];
+	int ret, forced = 0;
+
+	if (!capable(CAP_SYS_MODULE) || modules_disabled)
+		return -EPERM;
+
+	if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
+		return -EFAULT;
+	name[MODULE_NAME_LEN-1] = '\0';
+
+	audit_log_kern_module(name);
+
+	if (mutex_lock_interruptible(&module_mutex) != 0)
+		return -EINTR;
+
+	mod = find_module(name);
+	if (!mod) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	if (!list_empty(&mod->source_list)) {
+		/* Other modules depend on us: get rid of them first. */
+		ret = -EWOULDBLOCK;
+		goto out;
+	}
+
+	/* Doing init or already dying? */
+	if (mod->state != MODULE_STATE_LIVE) {
+		/* FIXME: if (force), slam module count damn the torpedoes */
+		pr_debug("%s already dying\n", mod->name);
+		ret = -EBUSY;
+		goto out;
+	}
+
+	/* If it has an init func, it must have an exit func to unload */
+	if (mod->init && !mod->exit) {
+		forced = try_force_unload(flags);
+		if (!forced) {
+			/* This module can't be removed */
+			ret = -EBUSY;
+			goto out;
+		}
+	}
+
+	ret = try_stop_module(mod, flags, &forced);
+	if (ret != 0)
+		goto out;
+
+	mutex_unlock(&module_mutex);
+	/* Final destruction now no one is using it. */
+	if (mod->exit != NULL)
+		mod->exit();
+	blocking_notifier_call_chain(&module_notify_list,
+				     MODULE_STATE_GOING, mod);
+	klp_module_going(mod);
+	ftrace_release_mod(mod);
+
+	async_synchronize_full();
+
+	/* Store the name and taints of the last unloaded module for diagnostic purposes */
+	strscpy(last_unloaded_module.name, mod->name, sizeof(last_unloaded_module.name));
+	strscpy(last_unloaded_module.taints, module_flags(mod, buf, false), sizeof(last_unloaded_module.taints));
+
+	free_module(mod);
+	/* someone could wait for the module in add_unformed_module() */
+	wake_up_all(&module_wq);
+	return 0;
+out:
+	mutex_unlock(&module_mutex);
+	return ret;
+}
+
+void __symbol_put(const char *symbol)
+{
+	struct find_symbol_arg fsa = {
+		.name	= symbol,
+		.gplok	= true,
+	};
+
+	preempt_disable();
+	BUG_ON(!find_symbol(&fsa));
+	module_put(fsa.owner);
+	preempt_enable();
+}
+EXPORT_SYMBOL(__symbol_put);
+
+/* Note this assumes addr is a function, which it currently always is. */
+void symbol_put_addr(void *addr)
+{
+	struct module *modaddr;
+	unsigned long a = (unsigned long)dereference_function_descriptor(addr);
+
+	if (core_kernel_text(a))
+		return;
+
+	/*
+	 * Even though we hold a reference on the module; we still need to
+	 * disable preemption in order to safely traverse the data structure.
+	 */
+	preempt_disable();
+	modaddr = __module_text_address(a);
+	BUG_ON(!modaddr);
+	module_put(modaddr);
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(symbol_put_addr);
+
+static ssize_t show_refcnt(struct module_attribute *mattr,
+			   struct module_kobject *mk, char *buffer)
+{
+	return sprintf(buffer, "%i\n", module_refcount(mk->mod));
+}
+
+static struct module_attribute modinfo_refcnt =
+	__ATTR(refcnt, 0444, show_refcnt, NULL);
+
+void __module_get(struct module *module)
+{
+	if (module) {
+		preempt_disable();
+		atomic_inc(&module->refcnt);
+		trace_module_get(module, _RET_IP_);
+		preempt_enable();
+	}
+}
+EXPORT_SYMBOL(__module_get);
+
+bool try_module_get(struct module *module)
+{
+	bool ret = true;
+
+	if (module) {
+		preempt_disable();
+		/* Note: here, we can fail to get a reference */
+		if (likely(module_is_live(module) &&
+			   atomic_inc_not_zero(&module->refcnt) != 0))
+			trace_module_get(module, _RET_IP_);
+		else
+			ret = false;
+
+		preempt_enable();
+	}
+	return ret;
+}
+EXPORT_SYMBOL(try_module_get);
+
+void module_put(struct module *module)
+{
+	int ret;
+
+	if (module) {
+		preempt_disable();
+		ret = atomic_dec_if_positive(&module->refcnt);
+		WARN_ON(ret < 0);	/* Failed to put refcount */
+		trace_module_put(module, _RET_IP_);
+		preempt_enable();
+	}
+}
+EXPORT_SYMBOL(module_put);
+
+#else /* !CONFIG_MODULE_UNLOAD */
+static inline void module_unload_free(struct module *mod)
+{
+}
+
+static int ref_module(struct module *a, struct module *b)
+{
+	return strong_try_module_get(b);
+}
+
+static inline int module_unload_init(struct module *mod)
+{
+	return 0;
+}
+#endif /* CONFIG_MODULE_UNLOAD */
+
+size_t module_flags_taint(unsigned long taints, char *buf)
+{
+	size_t l = 0;
+	int i;
+
+	for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
+		if (taint_flags[i].module && test_bit(i, &taints))
+			buf[l++] = taint_flags[i].c_true;
+	}
+
+	return l;
+}
+
+static ssize_t show_initstate(struct module_attribute *mattr,
+			      struct module_kobject *mk, char *buffer)
+{
+	const char *state = "unknown";
+
+	switch (mk->mod->state) {
+	case MODULE_STATE_LIVE:
+		state = "live";
+		break;
+	case MODULE_STATE_COMING:
+		state = "coming";
+		break;
+	case MODULE_STATE_GOING:
+		state = "going";
+		break;
+	default:
+		BUG();
+	}
+	return sprintf(buffer, "%s\n", state);
+}
+
+static struct module_attribute modinfo_initstate =
+	__ATTR(initstate, 0444, show_initstate, NULL);
+
+static ssize_t store_uevent(struct module_attribute *mattr,
+			    struct module_kobject *mk,
+			    const char *buffer, size_t count)
+{
+	int rc;
+
+	rc = kobject_synth_uevent(&mk->kobj, buffer, count);
+	return rc ? rc : count;
+}
+
+struct module_attribute module_uevent =
+	__ATTR(uevent, 0200, NULL, store_uevent);
+
+static ssize_t show_coresize(struct module_attribute *mattr,
+			     struct module_kobject *mk, char *buffer)
+{
+	return sprintf(buffer, "%u\n", mk->mod->core_layout.size);
+}
+
+static struct module_attribute modinfo_coresize =
+	__ATTR(coresize, 0444, show_coresize, NULL);
+
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+static ssize_t show_datasize(struct module_attribute *mattr,
+			     struct module_kobject *mk, char *buffer)
+{
+	return sprintf(buffer, "%u\n", mk->mod->data_layout.size);
+}
+
+static struct module_attribute modinfo_datasize =
+	__ATTR(datasize, 0444, show_datasize, NULL);
+#endif
+
+static ssize_t show_initsize(struct module_attribute *mattr,
+			     struct module_kobject *mk, char *buffer)
+{
+	return sprintf(buffer, "%u\n", mk->mod->init_layout.size);
+}
+
+static struct module_attribute modinfo_initsize =
+	__ATTR(initsize, 0444, show_initsize, NULL);
+
+static ssize_t show_taint(struct module_attribute *mattr,
+			  struct module_kobject *mk, char *buffer)
+{
+	size_t l;
+
+	l = module_flags_taint(mk->mod->taints, buffer);
+	buffer[l++] = '\n';
+	return l;
+}
+
+static struct module_attribute modinfo_taint =
+	__ATTR(taint, 0444, show_taint, NULL);
+
+struct module_attribute *modinfo_attrs[] = {
+	&module_uevent,
+	&modinfo_version,
+	&modinfo_srcversion,
+	&modinfo_initstate,
+	&modinfo_coresize,
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+	&modinfo_datasize,
+#endif
+	&modinfo_initsize,
+	&modinfo_taint,
+#ifdef CONFIG_MODULE_UNLOAD
+	&modinfo_refcnt,
+#endif
+	NULL,
+};
+
+size_t modinfo_attrs_count = ARRAY_SIZE(modinfo_attrs);
+
+static const char vermagic[] = VERMAGIC_STRING;
+
+int try_to_force_load(struct module *mod, const char *reason)
+{
+#ifdef CONFIG_MODULE_FORCE_LOAD
+	if (!test_taint(TAINT_FORCED_MODULE))
+		pr_warn("%s: %s: kernel tainted.\n", mod->name, reason);
+	add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_NOW_UNRELIABLE);
+	return 0;
+#else
+	return -ENOEXEC;
+#endif
+}
+
+static char *get_modinfo(const struct load_info *info, const char *tag);
+static char *get_next_modinfo(const struct load_info *info, const char *tag,
+			      char *prev);
+
+static int verify_namespace_is_imported(const struct load_info *info,
+					const struct kernel_symbol *sym,
+					struct module *mod)
+{
+	const char *namespace;
+	char *imported_namespace;
+
+	namespace = kernel_symbol_namespace(sym);
+	if (namespace && namespace[0]) {
+		imported_namespace = get_modinfo(info, "import_ns");
+		while (imported_namespace) {
+			if (strcmp(namespace, imported_namespace) == 0)
+				return 0;
+			imported_namespace = get_next_modinfo(
+				info, "import_ns", imported_namespace);
+		}
+#ifdef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
+		pr_warn(
+#else
+		pr_err(
+#endif
+			"%s: module uses symbol (%s) from namespace %s, but does not import it.\n",
+			mod->name, kernel_symbol_name(sym), namespace);
+#ifndef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
+		return -EINVAL;
+#endif
+	}
+	return 0;
+}
+
+static bool inherit_taint(struct module *mod, struct module *owner, const char *name)
+{
+	if (!owner || !test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints))
+		return true;
+
+	if (mod->using_gplonly_symbols) {
+		pr_err("%s: module using GPL-only symbols uses symbols %s from proprietary module %s.\n",
+			mod->name, name, owner->name);
+		return false;
+	}
+
+	if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) {
+		pr_warn("%s: module uses symbols %s from proprietary module %s, inheriting taint.\n",
+			mod->name, name, owner->name);
+		set_bit(TAINT_PROPRIETARY_MODULE, &mod->taints);
+	}
+	return true;
+}
+
+/* Resolve a symbol for this module.  I.e. if we find one, record usage. */
+static const struct kernel_symbol *resolve_symbol(struct module *mod,
+						  const struct load_info *info,
+						  const char *name,
+						  char ownername[])
+{
+	struct find_symbol_arg fsa = {
+		.name	= name,
+		.gplok	= !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)),
+		.warn	= true,
+	};
+	int err;
+
+	/*
+	 * The module_mutex should not be a heavily contended lock;
+	 * if we get the occasional sleep here, we'll go an extra iteration
+	 * in the wait_event_interruptible(), which is harmless.
+	 */
+	sched_annotate_sleep();
+	mutex_lock(&module_mutex);
+	if (!find_symbol(&fsa))
+		goto unlock;
+
+	if (fsa.license == GPL_ONLY)
+		mod->using_gplonly_symbols = true;
+
+	if (!inherit_taint(mod, fsa.owner, name)) {
+		fsa.sym = NULL;
+		goto getname;
+	}
+
+	if (!check_version(info, name, mod, fsa.crc)) {
+		fsa.sym = ERR_PTR(-EINVAL);
+		goto getname;
+	}
+
+	err = verify_namespace_is_imported(info, fsa.sym, mod);
+	if (err) {
+		fsa.sym = ERR_PTR(err);
+		goto getname;
+	}
+
+	err = ref_module(mod, fsa.owner);
+	if (err) {
+		fsa.sym = ERR_PTR(err);
+		goto getname;
+	}
+
+getname:
+	/* We must make copy under the lock if we failed to get ref. */
+	strncpy(ownername, module_name(fsa.owner), MODULE_NAME_LEN);
+unlock:
+	mutex_unlock(&module_mutex);
+	return fsa.sym;
+}
+
+static const struct kernel_symbol *
+resolve_symbol_wait(struct module *mod,
+		    const struct load_info *info,
+		    const char *name)
+{
+	const struct kernel_symbol *ksym;
+	char owner[MODULE_NAME_LEN];
+
+	if (wait_event_interruptible_timeout(module_wq,
+			!IS_ERR(ksym = resolve_symbol(mod, info, name, owner))
+			|| PTR_ERR(ksym) != -EBUSY,
+					     30 * HZ) <= 0) {
+		pr_warn("%s: gave up waiting for init of module %s.\n",
+			mod->name, owner);
+	}
+	return ksym;
+}
+
+void __weak module_memfree(void *module_region)
+{
+	/*
+	 * This memory may be RO, and freeing RO memory in an interrupt is not
+	 * supported by vmalloc.
+	 */
+	WARN_ON(in_interrupt());
+	vfree(module_region);
+}
+
+void __weak module_arch_cleanup(struct module *mod)
+{
+}
+
+void __weak module_arch_freeing_init(struct module *mod)
+{
+}
+
+/* Free a module, remove from lists, etc. */
+static void free_module(struct module *mod)
+{
+	trace_module_free(mod);
+
+	mod_sysfs_teardown(mod);
+
+	/*
+	 * We leave it in list to prevent duplicate loads, but make sure
+	 * that noone uses it while it's being deconstructed.
+	 */
+	mutex_lock(&module_mutex);
+	mod->state = MODULE_STATE_UNFORMED;
+	mutex_unlock(&module_mutex);
+
+	/* Remove dynamic debug info */
+	ddebug_remove_module(mod->name);
+
+	/* Arch-specific cleanup. */
+	module_arch_cleanup(mod);
+
+	/* Module unload stuff */
+	module_unload_free(mod);
+
+	/* Free any allocated parameters. */
+	destroy_params(mod->kp, mod->num_kp);
+
+	if (is_livepatch_module(mod))
+		free_module_elf(mod);
+
+	/* Now we can delete it from the lists */
+	mutex_lock(&module_mutex);
+	/* Unlink carefully: kallsyms could be walking list. */
+	list_del_rcu(&mod->list);
+	mod_tree_remove(mod);
+	/* Remove this module from bug list, this uses list_del_rcu */
+	module_bug_cleanup(mod);
+	/* Wait for RCU-sched synchronizing before releasing mod->list and buglist. */
+	synchronize_rcu();
+	if (try_add_tainted_module(mod))
+		pr_err("%s: adding tainted module to the unloaded tainted modules list failed.\n",
+		       mod->name);
+	mutex_unlock(&module_mutex);
+
+	/* This may be empty, but that's OK */
+	module_arch_freeing_init(mod);
+	module_memfree(mod->init_layout.base);
+	kfree(mod->args);
+	percpu_modfree(mod);
+
+	/* Free lock-classes; relies on the preceding sync_rcu(). */
+	lockdep_free_key_range(mod->data_layout.base, mod->data_layout.size);
+
+	/* Finally, free the core (containing the module structure) */
+	module_memfree(mod->core_layout.base);
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+	vfree(mod->data_layout.base);
+#endif
+}
+
+void *__symbol_get(const char *symbol)
+{
+	struct find_symbol_arg fsa = {
+		.name	= symbol,
+		.gplok	= true,
+		.warn	= true,
+	};
+
+	preempt_disable();
+	if (!find_symbol(&fsa))
+		goto fail;
+	if (fsa.license != GPL_ONLY) {
+		pr_warn("failing symbol_get of non-GPLONLY symbol %s.\n",
+			symbol);
+		goto fail;
+	}
+	if (strong_try_module_get(fsa.owner))
+		goto fail;
+	preempt_enable();
+	return (void *)kernel_symbol_value(fsa.sym);
+fail:
+	preempt_enable();
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(__symbol_get);
+
+/*
+ * Ensure that an exported symbol [global namespace] does not already exist
+ * in the kernel or in some other module's exported symbol table.
+ *
+ * You must hold the module_mutex.
+ */
+static int verify_exported_symbols(struct module *mod)
+{
+	unsigned int i;
+	const struct kernel_symbol *s;
+	struct {
+		const struct kernel_symbol *sym;
+		unsigned int num;
+	} arr[] = {
+		{ mod->syms, mod->num_syms },
+		{ mod->gpl_syms, mod->num_gpl_syms },
+	};
+
+	for (i = 0; i < ARRAY_SIZE(arr); i++) {
+		for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
+			struct find_symbol_arg fsa = {
+				.name	= kernel_symbol_name(s),
+				.gplok	= true,
+			};
+			if (find_symbol(&fsa)) {
+				pr_err("%s: exports duplicate symbol %s"
+				       " (owned by %s)\n",
+				       mod->name, kernel_symbol_name(s),
+				       module_name(fsa.owner));
+				return -ENOEXEC;
+			}
+		}
+	}
+	return 0;
+}
+
+static bool ignore_undef_symbol(Elf_Half emachine, const char *name)
+{
+	/*
+	 * On x86, PIC code and Clang non-PIC code may have call foo@PLT. GNU as
+	 * before 2.37 produces an unreferenced _GLOBAL_OFFSET_TABLE_ on x86-64.
+	 * i386 has a similar problem but may not deserve a fix.
+	 *
+	 * If we ever have to ignore many symbols, consider refactoring the code to
+	 * only warn if referenced by a relocation.
+	 */
+	if (emachine == EM_386 || emachine == EM_X86_64)
+		return !strcmp(name, "_GLOBAL_OFFSET_TABLE_");
+	return false;
+}
+
+/* Change all symbols so that st_value encodes the pointer directly. */
+static int simplify_symbols(struct module *mod, const struct load_info *info)
+{
+	Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
+	Elf_Sym *sym = (void *)symsec->sh_addr;
+	unsigned long secbase;
+	unsigned int i;
+	int ret = 0;
+	const struct kernel_symbol *ksym;
+
+	for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) {
+		const char *name = info->strtab + sym[i].st_name;
+
+		switch (sym[i].st_shndx) {
+		case SHN_COMMON:
+			/* Ignore common symbols */
+			if (!strncmp(name, "__gnu_lto", 9))
+				break;
+
+			/*
+			 * We compiled with -fno-common.  These are not
+			 * supposed to happen.
+			 */
+			pr_debug("Common symbol: %s\n", name);
+			pr_warn("%s: please compile with -fno-common\n",
+			       mod->name);
+			ret = -ENOEXEC;
+			break;
+
+		case SHN_ABS:
+			/* Don't need to do anything */
+			pr_debug("Absolute symbol: 0x%08lx\n",
+			       (long)sym[i].st_value);
+			break;
+
+		case SHN_LIVEPATCH:
+			/* Livepatch symbols are resolved by livepatch */
+			break;
+
+		case SHN_UNDEF:
+			ksym = resolve_symbol_wait(mod, info, name);
+			/* Ok if resolved.  */
+			if (ksym && !IS_ERR(ksym)) {
+				sym[i].st_value = kernel_symbol_value(ksym);
+				break;
+			}
+
+			/* Ok if weak or ignored.  */
+			if (!ksym &&
+			    (ELF_ST_BIND(sym[i].st_info) == STB_WEAK ||
+			     ignore_undef_symbol(info->hdr->e_machine, name)))
+				break;
+
+			ret = PTR_ERR(ksym) ?: -ENOENT;
+			pr_warn("%s: Unknown symbol %s (err %d)\n",
+				mod->name, name, ret);
+			break;
+
+		default:
+			/* Divert to percpu allocation if a percpu var. */
+			if (sym[i].st_shndx == info->index.pcpu)
+				secbase = (unsigned long)mod_percpu(mod);
+			else
+				secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
+			sym[i].st_value += secbase;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static int apply_relocations(struct module *mod, const struct load_info *info)
+{
+	unsigned int i;
+	int err = 0;
+
+	/* Now do relocations. */
+	for (i = 1; i < info->hdr->e_shnum; i++) {
+		unsigned int infosec = info->sechdrs[i].sh_info;
+
+		/* Not a valid relocation section? */
+		if (infosec >= info->hdr->e_shnum)
+			continue;
+
+		/* Don't bother with non-allocated sections */
+		if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
+			continue;
+
+		if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH)
+			err = klp_apply_section_relocs(mod, info->sechdrs,
+						       info->secstrings,
+						       info->strtab,
+						       info->index.sym, i,
+						       NULL);
+		else if (info->sechdrs[i].sh_type == SHT_REL)
+			err = apply_relocate(info->sechdrs, info->strtab,
+					     info->index.sym, i, mod);
+		else if (info->sechdrs[i].sh_type == SHT_RELA)
+			err = apply_relocate_add(info->sechdrs, info->strtab,
+						 info->index.sym, i, mod);
+		if (err < 0)
+			break;
+	}
+	return err;
+}
+
+/* Additional bytes needed by arch in front of individual sections */
+unsigned int __weak arch_mod_section_prepend(struct module *mod,
+					     unsigned int section)
+{
+	/* default implementation just returns zero */
+	return 0;
+}
+
+/* Update size with this section: return offset. */
+long module_get_offset(struct module *mod, unsigned int *size,
+		       Elf_Shdr *sechdr, unsigned int section)
+{
+	long ret;
+
+	*size += arch_mod_section_prepend(mod, section);
+	ret = ALIGN(*size, sechdr->sh_addralign ?: 1);
+	*size = ret + sechdr->sh_size;
+	return ret;
+}
+
+bool module_init_layout_section(const char *sname)
+{
+#ifndef CONFIG_MODULE_UNLOAD
+	if (module_exit_section(sname))
+		return true;
+#endif
+	return module_init_section(sname);
+}
+
+/*
+ * Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
+ * might -- code, read-only data, read-write data, small data.  Tally
+ * sizes, and place the offsets into sh_entsize fields: high bit means it
+ * belongs in init.
+ */
+static void layout_sections(struct module *mod, struct load_info *info)
+{
+	static unsigned long const masks[][2] = {
+		/*
+		 * NOTE: all executable code must be the first section
+		 * in this array; otherwise modify the text_size
+		 * finder in the two loops below
+		 */
+		{ SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },
+		{ SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },
+		{ SHF_RO_AFTER_INIT | SHF_ALLOC, ARCH_SHF_SMALL },
+		{ SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL },
+		{ ARCH_SHF_SMALL | SHF_ALLOC, 0 }
+	};
+	unsigned int m, i;
+
+	for (i = 0; i < info->hdr->e_shnum; i++)
+		info->sechdrs[i].sh_entsize = ~0UL;
+
+	pr_debug("Core section allocation order:\n");
+	for (m = 0; m < ARRAY_SIZE(masks); ++m) {
+		for (i = 0; i < info->hdr->e_shnum; ++i) {
+			Elf_Shdr *s = &info->sechdrs[i];
+			const char *sname = info->secstrings + s->sh_name;
+			unsigned int *sizep;
+
+			if ((s->sh_flags & masks[m][0]) != masks[m][0]
+			    || (s->sh_flags & masks[m][1])
+			    || s->sh_entsize != ~0UL
+			    || module_init_layout_section(sname))
+				continue;
+			sizep = m ? &mod->data_layout.size : &mod->core_layout.size;
+			s->sh_entsize = module_get_offset(mod, sizep, s, i);
+			pr_debug("\t%s\n", sname);
+		}
+		switch (m) {
+		case 0: /* executable */
+			mod->core_layout.size = strict_align(mod->core_layout.size);
+			mod->core_layout.text_size = mod->core_layout.size;
+			break;
+		case 1: /* RO: text and ro-data */
+			mod->data_layout.size = strict_align(mod->data_layout.size);
+			mod->data_layout.ro_size = mod->data_layout.size;
+			break;
+		case 2: /* RO after init */
+			mod->data_layout.size = strict_align(mod->data_layout.size);
+			mod->data_layout.ro_after_init_size = mod->data_layout.size;
+			break;
+		case 4: /* whole core */
+			mod->data_layout.size = strict_align(mod->data_layout.size);
+			break;
+		}
+	}
+
+	pr_debug("Init section allocation order:\n");
+	for (m = 0; m < ARRAY_SIZE(masks); ++m) {
+		for (i = 0; i < info->hdr->e_shnum; ++i) {
+			Elf_Shdr *s = &info->sechdrs[i];
+			const char *sname = info->secstrings + s->sh_name;
+
+			if ((s->sh_flags & masks[m][0]) != masks[m][0]
+			    || (s->sh_flags & masks[m][1])
+			    || s->sh_entsize != ~0UL
+			    || !module_init_layout_section(sname))
+				continue;
+			s->sh_entsize = (module_get_offset(mod, &mod->init_layout.size, s, i)
+					 | INIT_OFFSET_MASK);
+			pr_debug("\t%s\n", sname);
+		}
+		switch (m) {
+		case 0: /* executable */
+			mod->init_layout.size = strict_align(mod->init_layout.size);
+			mod->init_layout.text_size = mod->init_layout.size;
+			break;
+		case 1: /* RO: text and ro-data */
+			mod->init_layout.size = strict_align(mod->init_layout.size);
+			mod->init_layout.ro_size = mod->init_layout.size;
+			break;
+		case 2:
+			/*
+			 * RO after init doesn't apply to init_layout (only
+			 * core_layout), so it just takes the value of ro_size.
+			 */
+			mod->init_layout.ro_after_init_size = mod->init_layout.ro_size;
+			break;
+		case 4: /* whole init */
+			mod->init_layout.size = strict_align(mod->init_layout.size);
+			break;
+		}
+	}
+}
+
+static void set_license(struct module *mod, const char *license)
+{
+	if (!license)
+		license = "unspecified";
+
+	if (!license_is_gpl_compatible(license)) {
+		if (!test_taint(TAINT_PROPRIETARY_MODULE))
+			pr_warn("%s: module license '%s' taints kernel.\n",
+				mod->name, license);
+		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
+				 LOCKDEP_NOW_UNRELIABLE);
+	}
+}
+
+/* Parse tag=value strings from .modinfo section */
+static char *next_string(char *string, unsigned long *secsize)
+{
+	/* Skip non-zero chars */
+	while (string[0]) {
+		string++;
+		if ((*secsize)-- <= 1)
+			return NULL;
+	}
+
+	/* Skip any zero padding. */
+	while (!string[0]) {
+		string++;
+		if ((*secsize)-- <= 1)
+			return NULL;
+	}
+	return string;
+}
+
+static char *get_next_modinfo(const struct load_info *info, const char *tag,
+			      char *prev)
+{
+	char *p;
+	unsigned int taglen = strlen(tag);
+	Elf_Shdr *infosec = &info->sechdrs[info->index.info];
+	unsigned long size = infosec->sh_size;
+
+	/*
+	 * get_modinfo() calls made before rewrite_section_headers()
+	 * must use sh_offset, as sh_addr isn't set!
+	 */
+	char *modinfo = (char *)info->hdr + infosec->sh_offset;
+
+	if (prev) {
+		size -= prev - modinfo;
+		modinfo = next_string(prev, &size);
+	}
+
+	for (p = modinfo; p; p = next_string(p, &size)) {
+		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
+			return p + taglen + 1;
+	}
+	return NULL;
+}
+
+static char *get_modinfo(const struct load_info *info, const char *tag)
+{
+	return get_next_modinfo(info, tag, NULL);
+}
+
+static void setup_modinfo(struct module *mod, struct load_info *info)
+{
+	struct module_attribute *attr;
+	int i;
+
+	for (i = 0; (attr = modinfo_attrs[i]); i++) {
+		if (attr->setup)
+			attr->setup(mod, get_modinfo(info, attr->attr.name));
+	}
+}
+
+static void free_modinfo(struct module *mod)
+{
+	struct module_attribute *attr;
+	int i;
+
+	for (i = 0; (attr = modinfo_attrs[i]); i++) {
+		if (attr->free)
+			attr->free(mod);
+	}
+}
+
+static void dynamic_debug_setup(struct module *mod, struct _ddebug_info *dyndbg)
+{
+	if (!dyndbg->num_descs)
+		return;
+	ddebug_add_module(dyndbg, mod->name);
+}
+
+static void dynamic_debug_remove(struct module *mod, struct _ddebug_info *dyndbg)
+{
+	if (dyndbg->num_descs)
+		ddebug_remove_module(mod->name);
+}
+
+void * __weak module_alloc(unsigned long size)
+{
+	return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
+			GFP_KERNEL, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS,
+			NUMA_NO_NODE, __builtin_return_address(0));
+}
+
+bool __weak module_init_section(const char *name)
+{
+	return strstarts(name, ".init");
+}
+
+bool __weak module_exit_section(const char *name)
+{
+	return strstarts(name, ".exit");
+}
+
+static int validate_section_offset(struct load_info *info, Elf_Shdr *shdr)
+{
+#if defined(CONFIG_64BIT)
+	unsigned long long secend;
+#else
+	unsigned long secend;
+#endif
+
+	/*
+	 * Check for both overflow and offset/size being
+	 * too large.
+	 */
+	secend = shdr->sh_offset + shdr->sh_size;
+	if (secend < shdr->sh_offset || secend > info->len)
+		return -ENOEXEC;
+
+	return 0;
+}
+
+/*
+ * Sanity checks against invalid binaries, wrong arch, weird elf version.
+ *
+ * Also do basic validity checks against section offsets and sizes, the
+ * section name string table, and the indices used for it (sh_name).
+ */
+static int elf_validity_check(struct load_info *info)
+{
+	unsigned int i;
+	Elf_Shdr *shdr, *strhdr;
+	int err;
+
+	if (info->len < sizeof(*(info->hdr))) {
+		pr_err("Invalid ELF header len %lu\n", info->len);
+		goto no_exec;
+	}
+
+	if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0) {
+		pr_err("Invalid ELF header magic: != %s\n", ELFMAG);
+		goto no_exec;
+	}
+	if (info->hdr->e_type != ET_REL) {
+		pr_err("Invalid ELF header type: %u != %u\n",
+		       info->hdr->e_type, ET_REL);
+		goto no_exec;
+	}
+	if (!elf_check_arch(info->hdr)) {
+		pr_err("Invalid architecture in ELF header: %u\n",
+		       info->hdr->e_machine);
+		goto no_exec;
+	}
+	if (info->hdr->e_shentsize != sizeof(Elf_Shdr)) {
+		pr_err("Invalid ELF section header size\n");
+		goto no_exec;
+	}
+
+	/*
+	 * e_shnum is 16 bits, and sizeof(Elf_Shdr) is
+	 * known and small. So e_shnum * sizeof(Elf_Shdr)
+	 * will not overflow unsigned long on any platform.
+	 */
+	if (info->hdr->e_shoff >= info->len
+	    || (info->hdr->e_shnum * sizeof(Elf_Shdr) >
+		info->len - info->hdr->e_shoff)) {
+		pr_err("Invalid ELF section header overflow\n");
+		goto no_exec;
+	}
+
+	info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
+
+	/*
+	 * Verify if the section name table index is valid.
+	 */
+	if (info->hdr->e_shstrndx == SHN_UNDEF
+	    || info->hdr->e_shstrndx >= info->hdr->e_shnum) {
+		pr_err("Invalid ELF section name index: %d || e_shstrndx (%d) >= e_shnum (%d)\n",
+		       info->hdr->e_shstrndx, info->hdr->e_shstrndx,
+		       info->hdr->e_shnum);
+		goto no_exec;
+	}
+
+	strhdr = &info->sechdrs[info->hdr->e_shstrndx];
+	err = validate_section_offset(info, strhdr);
+	if (err < 0) {
+		pr_err("Invalid ELF section hdr(type %u)\n", strhdr->sh_type);
+		return err;
+	}
+
+	/*
+	 * The section name table must be NUL-terminated, as required
+	 * by the spec. This makes strcmp and pr_* calls that access
+	 * strings in the section safe.
+	 */
+	info->secstrings = (void *)info->hdr + strhdr->sh_offset;
+	if (strhdr->sh_size == 0) {
+		pr_err("empty section name table\n");
+		goto no_exec;
+	}
+	if (info->secstrings[strhdr->sh_size - 1] != '\0') {
+		pr_err("ELF Spec violation: section name table isn't null terminated\n");
+		goto no_exec;
+	}
+
+	/*
+	 * The code assumes that section 0 has a length of zero and
+	 * an addr of zero, so check for it.
+	 */
+	if (info->sechdrs[0].sh_type != SHT_NULL
+	    || info->sechdrs[0].sh_size != 0
+	    || info->sechdrs[0].sh_addr != 0) {
+		pr_err("ELF Spec violation: section 0 type(%d)!=SH_NULL or non-zero len or addr\n",
+		       info->sechdrs[0].sh_type);
+		goto no_exec;
+	}
+
+	for (i = 1; i < info->hdr->e_shnum; i++) {
+		shdr = &info->sechdrs[i];
+		switch (shdr->sh_type) {
+		case SHT_NULL:
+		case SHT_NOBITS:
+			continue;
+		case SHT_SYMTAB:
+			if (shdr->sh_link == SHN_UNDEF
+			    || shdr->sh_link >= info->hdr->e_shnum) {
+				pr_err("Invalid ELF sh_link!=SHN_UNDEF(%d) or (sh_link(%d) >= hdr->e_shnum(%d)\n",
+				       shdr->sh_link, shdr->sh_link,
+				       info->hdr->e_shnum);
+				goto no_exec;
+			}
+			fallthrough;
+		default:
+			err = validate_section_offset(info, shdr);
+			if (err < 0) {
+				pr_err("Invalid ELF section in module (section %u type %u)\n",
+					i, shdr->sh_type);
+				return err;
+			}
+
+			if (shdr->sh_flags & SHF_ALLOC) {
+				if (shdr->sh_name >= strhdr->sh_size) {
+					pr_err("Invalid ELF section name in module (section %u type %u)\n",
+					       i, shdr->sh_type);
+					return -ENOEXEC;
+				}
+			}
+			break;
+		}
+	}
+
+	return 0;
+
+no_exec:
+	return -ENOEXEC;
+}
+
+#define COPY_CHUNK_SIZE (16*PAGE_SIZE)
+
+static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned long len)
+{
+	do {
+		unsigned long n = min(len, COPY_CHUNK_SIZE);
+
+		if (copy_from_user(dst, usrc, n) != 0)
+			return -EFAULT;
+		cond_resched();
+		dst += n;
+		usrc += n;
+		len -= n;
+	} while (len);
+	return 0;
+}
+
+static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
+{
+	if (!get_modinfo(info, "livepatch"))
+		/* Nothing more to do */
+		return 0;
+
+	if (set_livepatch_module(mod)) {
+		add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
+		pr_notice_once("%s: tainting kernel with TAINT_LIVEPATCH\n",
+				mod->name);
+		return 0;
+	}
+
+	pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
+	       mod->name);
+	return -ENOEXEC;
+}
+
+static void check_modinfo_retpoline(struct module *mod, struct load_info *info)
+{
+	if (retpoline_module_ok(get_modinfo(info, "retpoline")))
+		return;
+
+	pr_warn("%s: loading module not compiled with retpoline compiler.\n",
+		mod->name);
+}
+
+/* Sets info->hdr and info->len. */
+static int copy_module_from_user(const void __user *umod, unsigned long len,
+				  struct load_info *info)
+{
+	int err;
+
+	info->len = len;
+	if (info->len < sizeof(*(info->hdr)))
+		return -ENOEXEC;
+
+	err = security_kernel_load_data(LOADING_MODULE, true);
+	if (err)
+		return err;
+
+	/* Suck in entire file: we'll want most of it. */
+	info->hdr = __vmalloc(info->len, GFP_KERNEL | __GFP_NOWARN);
+	if (!info->hdr)
+		return -ENOMEM;
+
+	if (copy_chunked_from_user(info->hdr, umod, info->len) != 0) {
+		err = -EFAULT;
+		goto out;
+	}
+
+	err = security_kernel_post_load_data((char *)info->hdr, info->len,
+					     LOADING_MODULE, "init_module");
+out:
+	if (err)
+		vfree(info->hdr);
+
+	return err;
+}
+
+static void free_copy(struct load_info *info, int flags)
+{
+	if (flags & MODULE_INIT_COMPRESSED_FILE)
+		module_decompress_cleanup(info);
+	else
+		vfree(info->hdr);
+}
+
+static int rewrite_section_headers(struct load_info *info, int flags)
+{
+	unsigned int i;
+
+	/* This should always be true, but let's be sure. */
+	info->sechdrs[0].sh_addr = 0;
+
+	for (i = 1; i < info->hdr->e_shnum; i++) {
+		Elf_Shdr *shdr = &info->sechdrs[i];
+
+		/*
+		 * Mark all sections sh_addr with their address in the
+		 * temporary image.
+		 */
+		shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset;
+
+	}
+
+	/* Track but don't keep modinfo and version sections. */
+	info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
+	info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
+
+	return 0;
+}
+
+/*
+ * Set up our basic convenience variables (pointers to section headers,
+ * search for module section index etc), and do some basic section
+ * verification.
+ *
+ * Set info->mod to the temporary copy of the module in info->hdr. The final one
+ * will be allocated in move_module().
+ */
+static int setup_load_info(struct load_info *info, int flags)
+{
+	unsigned int i;
+
+	/* Try to find a name early so we can log errors with a module name */
+	info->index.info = find_sec(info, ".modinfo");
+	if (info->index.info)
+		info->name = get_modinfo(info, "name");
+
+	/* Find internal symbols and strings. */
+	for (i = 1; i < info->hdr->e_shnum; i++) {
+		if (info->sechdrs[i].sh_type == SHT_SYMTAB) {
+			info->index.sym = i;
+			info->index.str = info->sechdrs[i].sh_link;
+			info->strtab = (char *)info->hdr
+				+ info->sechdrs[info->index.str].sh_offset;
+			break;
+		}
+	}
+
+	if (info->index.sym == 0) {
+		pr_warn("%s: module has no symbols (stripped?)\n",
+			info->name ?: "(missing .modinfo section or name field)");
+		return -ENOEXEC;
+	}
+
+	info->index.mod = find_sec(info, ".gnu.linkonce.this_module");
+	if (!info->index.mod) {
+		pr_warn("%s: No module found in object\n",
+			info->name ?: "(missing .modinfo section or name field)");
+		return -ENOEXEC;
+	}
+	/* This is temporary: point mod into copy of data. */
+	info->mod = (void *)info->hdr + info->sechdrs[info->index.mod].sh_offset;
+
+	/*
+	 * If we didn't load the .modinfo 'name' field earlier, fall back to
+	 * on-disk struct mod 'name' field.
+	 */
+	if (!info->name)
+		info->name = info->mod->name;
+
+	if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
+		info->index.vers = 0; /* Pretend no __versions section! */
+	else
+		info->index.vers = find_sec(info, "__versions");
+
+	info->index.pcpu = find_pcpusec(info);
+
+	return 0;
+}
+
+static int check_modinfo(struct module *mod, struct load_info *info, int flags)
+{
+	const char *modmagic = get_modinfo(info, "vermagic");
+	int err;
+
+	if (flags & MODULE_INIT_IGNORE_VERMAGIC)
+		modmagic = NULL;
+
+	/* This is allowed: modprobe --force will invalidate it. */
+	if (!modmagic) {
+		err = try_to_force_load(mod, "bad vermagic");
+		if (err)
+			return err;
+	} else if (!same_magic(modmagic, vermagic, info->index.vers)) {
+		pr_err("%s: version magic '%s' should be '%s'\n",
+		       info->name, modmagic, vermagic);
+		return -ENOEXEC;
+	}
+
+	if (!get_modinfo(info, "intree")) {
+		if (!test_taint(TAINT_OOT_MODULE))
+			pr_warn("%s: loading out-of-tree module taints kernel.\n",
+				mod->name);
+		add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK);
+	}
+
+	check_modinfo_retpoline(mod, info);
+
+	if (get_modinfo(info, "staging")) {
+		add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK);
+		pr_warn("%s: module is from the staging directory, the quality "
+			"is unknown, you have been warned.\n", mod->name);
+	}
+
+	err = check_modinfo_livepatch(mod, info);
+	if (err)
+		return err;
+
+	/* Set up license info based on the info section */
+	set_license(mod, get_modinfo(info, "license"));
+
+	if (get_modinfo(info, "test")) {
+		if (!test_taint(TAINT_TEST))
+			pr_warn("%s: loading test module taints kernel.\n",
+				mod->name);
+		add_taint_module(mod, TAINT_TEST, LOCKDEP_STILL_OK);
+	}
+
+	return 0;
+}
+
+static int find_module_sections(struct module *mod, struct load_info *info)
+{
+	mod->kp = section_objs(info, "__param",
+			       sizeof(*mod->kp), &mod->num_kp);
+	mod->syms = section_objs(info, "__ksymtab",
+				 sizeof(*mod->syms), &mod->num_syms);
+	mod->crcs = section_addr(info, "__kcrctab");
+	mod->gpl_syms = section_objs(info, "__ksymtab_gpl",
+				     sizeof(*mod->gpl_syms),
+				     &mod->num_gpl_syms);
+	mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
+
+#ifdef CONFIG_CONSTRUCTORS
+	mod->ctors = section_objs(info, ".ctors",
+				  sizeof(*mod->ctors), &mod->num_ctors);
+	if (!mod->ctors)
+		mod->ctors = section_objs(info, ".init_array",
+				sizeof(*mod->ctors), &mod->num_ctors);
+	else if (find_sec(info, ".init_array")) {
+		/*
+		 * This shouldn't happen with same compiler and binutils
+		 * building all parts of the module.
+		 */
+		pr_warn("%s: has both .ctors and .init_array.\n",
+		       mod->name);
+		return -EINVAL;
+	}
+#endif
+
+	mod->noinstr_text_start = section_objs(info, ".noinstr.text", 1,
+						&mod->noinstr_text_size);
+
+#ifdef CONFIG_TRACEPOINTS
+	mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
+					     sizeof(*mod->tracepoints_ptrs),
+					     &mod->num_tracepoints);
+#endif
+#ifdef CONFIG_TREE_SRCU
+	mod->srcu_struct_ptrs = section_objs(info, "___srcu_struct_ptrs",
+					     sizeof(*mod->srcu_struct_ptrs),
+					     &mod->num_srcu_structs);
+#endif
+#ifdef CONFIG_BPF_EVENTS
+	mod->bpf_raw_events = section_objs(info, "__bpf_raw_tp_map",
+					   sizeof(*mod->bpf_raw_events),
+					   &mod->num_bpf_raw_events);
+#endif
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+	mod->btf_data = any_section_objs(info, ".BTF", 1, &mod->btf_data_size);
+#endif
+#ifdef CONFIG_JUMP_LABEL
+	mod->jump_entries = section_objs(info, "__jump_table",
+					sizeof(*mod->jump_entries),
+					&mod->num_jump_entries);
+#endif
+#ifdef CONFIG_EVENT_TRACING
+	mod->trace_events = section_objs(info, "_ftrace_events",
+					 sizeof(*mod->trace_events),
+					 &mod->num_trace_events);
+	mod->trace_evals = section_objs(info, "_ftrace_eval_map",
+					sizeof(*mod->trace_evals),
+					&mod->num_trace_evals);
+#endif
+#ifdef CONFIG_TRACING
+	mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
+					 sizeof(*mod->trace_bprintk_fmt_start),
+					 &mod->num_trace_bprintk_fmt);
+#endif
+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+	/* sechdrs[0].sh_size is always zero */
+	mod->ftrace_callsites = section_objs(info, FTRACE_CALLSITE_SECTION,
+					     sizeof(*mod->ftrace_callsites),
+					     &mod->num_ftrace_callsites);
+#endif
+#ifdef CONFIG_FUNCTION_ERROR_INJECTION
+	mod->ei_funcs = section_objs(info, "_error_injection_whitelist",
+					    sizeof(*mod->ei_funcs),
+					    &mod->num_ei_funcs);
+#endif
+#ifdef CONFIG_KPROBES
+	mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1,
+						&mod->kprobes_text_size);
+	mod->kprobe_blacklist = section_objs(info, "_kprobe_blacklist",
+						sizeof(unsigned long),
+						&mod->num_kprobe_blacklist);
+#endif
+#ifdef CONFIG_PRINTK_INDEX
+	mod->printk_index_start = section_objs(info, ".printk_index",
+					       sizeof(*mod->printk_index_start),
+					       &mod->printk_index_size);
+#endif
+#ifdef CONFIG_HAVE_STATIC_CALL_INLINE
+	mod->static_call_sites = section_objs(info, ".static_call_sites",
+					      sizeof(*mod->static_call_sites),
+					      &mod->num_static_call_sites);
+#endif
+#if IS_ENABLED(CONFIG_KUNIT)
+	mod->kunit_suites = section_objs(info, ".kunit_test_suites",
+					      sizeof(*mod->kunit_suites),
+					      &mod->num_kunit_suites);
+#endif
+
+	mod->extable = section_objs(info, "__ex_table",
+				    sizeof(*mod->extable), &mod->num_exentries);
+
+	if (section_addr(info, "__obsparm"))
+		pr_warn("%s: Ignoring obsolete parameters\n", mod->name);
+
+	info->dyndbg.descs = section_objs(info, "__dyndbg",
+					sizeof(*info->dyndbg.descs), &info->dyndbg.num_descs);
+	info->dyndbg.classes = section_objs(info, "__dyndbg_classes",
+					sizeof(*info->dyndbg.classes), &info->dyndbg.num_classes);
+
+	return 0;
+}
+
+static int move_module(struct module *mod, struct load_info *info)
+{
+	int i;
+	void *ptr;
+
+	/* Do the allocs. */
+	ptr = module_alloc(mod->core_layout.size);
+	/*
+	 * The pointer to this block is stored in the module structure
+	 * which is inside the block. Just mark it as not being a
+	 * leak.
+	 */
+	kmemleak_not_leak(ptr);
+	if (!ptr)
+		return -ENOMEM;
+
+	memset(ptr, 0, mod->core_layout.size);
+	mod->core_layout.base = ptr;
+
+	if (mod->init_layout.size) {
+		ptr = module_alloc(mod->init_layout.size);
+		/*
+		 * The pointer to this block is stored in the module structure
+		 * which is inside the block. This block doesn't need to be
+		 * scanned as it contains data and code that will be freed
+		 * after the module is initialized.
+		 */
+		kmemleak_ignore(ptr);
+		if (!ptr) {
+			module_memfree(mod->core_layout.base);
+			return -ENOMEM;
+		}
+		memset(ptr, 0, mod->init_layout.size);
+		mod->init_layout.base = ptr;
+	} else
+		mod->init_layout.base = NULL;
+
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+	/* Do the allocs. */
+	ptr = vzalloc(mod->data_layout.size);
+	/*
+	 * The pointer to this block is stored in the module structure
+	 * which is inside the block. Just mark it as not being a
+	 * leak.
+	 */
+	kmemleak_not_leak(ptr);
+	if (!ptr) {
+		module_memfree(mod->core_layout.base);
+		module_memfree(mod->init_layout.base);
+		return -ENOMEM;
+	}
+
+	mod->data_layout.base = ptr;
+#endif
+	/* Transfer each section which specifies SHF_ALLOC */
+	pr_debug("final section addresses:\n");
+	for (i = 0; i < info->hdr->e_shnum; i++) {
+		void *dest;
+		Elf_Shdr *shdr = &info->sechdrs[i];
+
+		if (!(shdr->sh_flags & SHF_ALLOC))
+			continue;
+
+		if (shdr->sh_entsize & INIT_OFFSET_MASK)
+			dest = mod->init_layout.base
+				+ (shdr->sh_entsize & ~INIT_OFFSET_MASK);
+		else if (!(shdr->sh_flags & SHF_EXECINSTR))
+			dest = mod->data_layout.base + shdr->sh_entsize;
+		else
+			dest = mod->core_layout.base + shdr->sh_entsize;
+
+		if (shdr->sh_type != SHT_NOBITS)
+			memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size);
+		/* Update sh_addr to point to copy in image. */
+		shdr->sh_addr = (unsigned long)dest;
+		pr_debug("\t0x%lx %s\n",
+			 (long)shdr->sh_addr, info->secstrings + shdr->sh_name);
+	}
+
+	return 0;
+}
+
+static int check_module_license_and_versions(struct module *mod)
+{
+	int prev_taint = test_taint(TAINT_PROPRIETARY_MODULE);
+
+	/*
+	 * ndiswrapper is under GPL by itself, but loads proprietary modules.
+	 * Don't use add_taint_module(), as it would prevent ndiswrapper from
+	 * using GPL-only symbols it needs.
+	 */
+	if (strcmp(mod->name, "ndiswrapper") == 0)
+		add_taint(TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE);
+
+	/* driverloader was caught wrongly pretending to be under GPL */
+	if (strcmp(mod->name, "driverloader") == 0)
+		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
+				 LOCKDEP_NOW_UNRELIABLE);
+
+	/* lve claims to be GPL but upstream won't provide source */
+	if (strcmp(mod->name, "lve") == 0)
+		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
+				 LOCKDEP_NOW_UNRELIABLE);
+
+	if (!prev_taint && test_taint(TAINT_PROPRIETARY_MODULE))
+		pr_warn("%s: module license taints kernel.\n", mod->name);
+
+#ifdef CONFIG_MODVERSIONS
+	if ((mod->num_syms && !mod->crcs) ||
+	    (mod->num_gpl_syms && !mod->gpl_crcs)) {
+		return try_to_force_load(mod,
+					 "no versions for exported symbols");
+	}
+#endif
+	return 0;
+}
+
+static void flush_module_icache(const struct module *mod)
+{
+	/*
+	 * Flush the instruction cache, since we've played with text.
+	 * Do it before processing of module parameters, so the module
+	 * can provide parameter accessor functions of its own.
+	 */
+	if (mod->init_layout.base)
+		flush_icache_range((unsigned long)mod->init_layout.base,
+				   (unsigned long)mod->init_layout.base
+				   + mod->init_layout.size);
+	flush_icache_range((unsigned long)mod->core_layout.base,
+			   (unsigned long)mod->core_layout.base + mod->core_layout.size);
+}
+
+int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
+				     Elf_Shdr *sechdrs,
+				     char *secstrings,
+				     struct module *mod)
+{
+	return 0;
+}
+
+/* module_blacklist is a comma-separated list of module names */
+static char *module_blacklist;
+static bool blacklisted(const char *module_name)
+{
+	const char *p;
+	size_t len;
+
+	if (!module_blacklist)
+		return false;
+
+	for (p = module_blacklist; *p; p += len) {
+		len = strcspn(p, ",");
+		if (strlen(module_name) == len && !memcmp(module_name, p, len))
+			return true;
+		if (p[len] == ',')
+			len++;
+	}
+	return false;
+}
+core_param(module_blacklist, module_blacklist, charp, 0400);
+
+static struct module *layout_and_allocate(struct load_info *info, int flags)
+{
+	struct module *mod;
+	unsigned int ndx;
+	int err;
+
+	err = check_modinfo(info->mod, info, flags);
+	if (err)
+		return ERR_PTR(err);
+
+	/* Allow arches to frob section contents and sizes.  */
+	err = module_frob_arch_sections(info->hdr, info->sechdrs,
+					info->secstrings, info->mod);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	err = module_enforce_rwx_sections(info->hdr, info->sechdrs,
+					  info->secstrings, info->mod);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	/* We will do a special allocation for per-cpu sections later. */
+	info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
+
+	/*
+	 * Mark ro_after_init section with SHF_RO_AFTER_INIT so that
+	 * layout_sections() can put it in the right place.
+	 * Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set.
+	 */
+	ndx = find_sec(info, ".data..ro_after_init");
+	if (ndx)
+		info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
+	/*
+	 * Mark the __jump_table section as ro_after_init as well: these data
+	 * structures are never modified, with the exception of entries that
+	 * refer to code in the __init section, which are annotated as such
+	 * at module load time.
+	 */
+	ndx = find_sec(info, "__jump_table");
+	if (ndx)
+		info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
+
+	/*
+	 * Determine total sizes, and put offsets in sh_entsize.  For now
+	 * this is done generically; there doesn't appear to be any
+	 * special cases for the architectures.
+	 */
+	layout_sections(info->mod, info);
+	layout_symtab(info->mod, info);
+
+	/* Allocate and move to the final place */
+	err = move_module(info->mod, info);
+	if (err)
+		return ERR_PTR(err);
+
+	/* Module has been copied to its final place now: return it. */
+	mod = (void *)info->sechdrs[info->index.mod].sh_addr;
+	kmemleak_load_module(mod, info);
+	return mod;
+}
+
+/* mod is no longer valid after this! */
+static void module_deallocate(struct module *mod, struct load_info *info)
+{
+	percpu_modfree(mod);
+	module_arch_freeing_init(mod);
+	module_memfree(mod->init_layout.base);
+	module_memfree(mod->core_layout.base);
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+	vfree(mod->data_layout.base);
+#endif
+}
+
+int __weak module_finalize(const Elf_Ehdr *hdr,
+			   const Elf_Shdr *sechdrs,
+			   struct module *me)
+{
+	return 0;
+}
+
+static int post_relocation(struct module *mod, const struct load_info *info)
+{
+	/* Sort exception table now relocations are done. */
+	sort_extable(mod->extable, mod->extable + mod->num_exentries);
+
+	/* Copy relocated percpu area over. */
+	percpu_modcopy(mod, (void *)info->sechdrs[info->index.pcpu].sh_addr,
+		       info->sechdrs[info->index.pcpu].sh_size);
+
+	/* Setup kallsyms-specific fields. */
+	add_kallsyms(mod, info);
+
+	/* Arch-specific module finalizing. */
+	return module_finalize(info->hdr, info->sechdrs, mod);
+}
+
+/* Is this module of this name done loading?  No locks held. */
+static bool finished_loading(const char *name)
+{
+	struct module *mod;
+	bool ret;
+
+	/*
+	 * The module_mutex should not be a heavily contended lock;
+	 * if we get the occasional sleep here, we'll go an extra iteration
+	 * in the wait_event_interruptible(), which is harmless.
+	 */
+	sched_annotate_sleep();
+	mutex_lock(&module_mutex);
+	mod = find_module_all(name, strlen(name), true);
+	ret = !mod || mod->state == MODULE_STATE_LIVE
+		|| mod->state == MODULE_STATE_GOING;
+	mutex_unlock(&module_mutex);
+
+	return ret;
+}
+
+/* Call module constructors. */
+static void do_mod_ctors(struct module *mod)
+{
+#ifdef CONFIG_CONSTRUCTORS
+	unsigned long i;
+
+	for (i = 0; i < mod->num_ctors; i++)
+		mod->ctors[i]();
+#endif
+}
+
+/* For freeing module_init on success, in case kallsyms traversing */
+struct mod_initfree {
+	struct llist_node node;
+	void *module_init;
+};
+
+static void do_free_init(struct work_struct *w)
+{
+	struct llist_node *pos, *n, *list;
+	struct mod_initfree *initfree;
+
+	list = llist_del_all(&init_free_list);
+
+	synchronize_rcu();
+
+	llist_for_each_safe(pos, n, list) {
+		initfree = container_of(pos, struct mod_initfree, node);
+		module_memfree(initfree->module_init);
+		kfree(initfree);
+	}
+}
+
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX "module."
+/* Default value for module->async_probe_requested */
+static bool async_probe;
+module_param(async_probe, bool, 0644);
+
+/*
+ * This is where the real work happens.
+ *
+ * Keep it uninlined to provide a reliable breakpoint target, e.g. for the gdb
+ * helper command 'lx-symbols'.
+ */
+static noinline int do_init_module(struct module *mod)
+{
+	int ret = 0;
+	struct mod_initfree *freeinit;
+
+	freeinit = kmalloc(sizeof(*freeinit), GFP_KERNEL);
+	if (!freeinit) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+	freeinit->module_init = mod->init_layout.base;
+
+	do_mod_ctors(mod);
+	/* Start the module */
+	if (mod->init != NULL)
+		ret = do_one_initcall(mod->init);
+	if (ret < 0) {
+		goto fail_free_freeinit;
+	}
+	if (ret > 0) {
+		pr_warn("%s: '%s'->init suspiciously returned %d, it should "
+			"follow 0/-E convention\n"
+			"%s: loading module anyway...\n",
+			__func__, mod->name, ret, __func__);
+		dump_stack();
+	}
+
+	/* Now it's a first class citizen! */
+	mod->state = MODULE_STATE_LIVE;
+	blocking_notifier_call_chain(&module_notify_list,
+				     MODULE_STATE_LIVE, mod);
+
+	/* Delay uevent until module has finished its init routine */
+	kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
+
+	/*
+	 * We need to finish all async code before the module init sequence
+	 * is done. This has potential to deadlock if synchronous module
+	 * loading is requested from async (which is not allowed!).
+	 *
+	 * See commit 0fdff3ec6d87 ("async, kmod: warn on synchronous
+	 * request_module() from async workers") for more details.
+	 */
+	if (!mod->async_probe_requested)
+		async_synchronize_full();
+
+	ftrace_free_mem(mod, mod->init_layout.base, mod->init_layout.base +
+			mod->init_layout.size);
+	mutex_lock(&module_mutex);
+	/* Drop initial reference. */
+	module_put(mod);
+	trim_init_extable(mod);
+#ifdef CONFIG_KALLSYMS
+	/* Switch to core kallsyms now init is done: kallsyms may be walking! */
+	rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms);
+#endif
+	module_enable_ro(mod, true);
+	mod_tree_remove_init(mod);
+	module_arch_freeing_init(mod);
+	mod->init_layout.base = NULL;
+	mod->init_layout.size = 0;
+	mod->init_layout.ro_size = 0;
+	mod->init_layout.ro_after_init_size = 0;
+	mod->init_layout.text_size = 0;
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+	/* .BTF is not SHF_ALLOC and will get removed, so sanitize pointer */
+	mod->btf_data = NULL;
+#endif
+	/*
+	 * We want to free module_init, but be aware that kallsyms may be
+	 * walking this with preempt disabled.  In all the failure paths, we
+	 * call synchronize_rcu(), but we don't want to slow down the success
+	 * path. module_memfree() cannot be called in an interrupt, so do the
+	 * work and call synchronize_rcu() in a work queue.
+	 *
+	 * Note that module_alloc() on most architectures creates W+X page
+	 * mappings which won't be cleaned up until do_free_init() runs.  Any
+	 * code such as mark_rodata_ro() which depends on those mappings to
+	 * be cleaned up needs to sync with the queued work - ie
+	 * rcu_barrier()
+	 */
+	if (llist_add(&freeinit->node, &init_free_list))
+		schedule_work(&init_free_wq);
+
+	mutex_unlock(&module_mutex);
+	wake_up_all(&module_wq);
+
+	return 0;
+
+fail_free_freeinit:
+	kfree(freeinit);
+fail:
+	/* Try to protect us from buggy refcounters. */
+	mod->state = MODULE_STATE_GOING;
+	synchronize_rcu();
+	module_put(mod);
+	blocking_notifier_call_chain(&module_notify_list,
+				     MODULE_STATE_GOING, mod);
+	klp_module_going(mod);
+	ftrace_release_mod(mod);
+	free_module(mod);
+	wake_up_all(&module_wq);
+	return ret;
+}
+
+static int may_init_module(void)
+{
+	if (!capable(CAP_SYS_MODULE) || modules_disabled)
+		return -EPERM;
+
+	return 0;
+}
+
+/*
+ * We try to place it in the list now to make sure it's unique before
+ * we dedicate too many resources.  In particular, temporary percpu
+ * memory exhaustion.
+ */
+static int add_unformed_module(struct module *mod)
+{
+	int err;
+	struct module *old;
+
+	mod->state = MODULE_STATE_UNFORMED;
+
+	mutex_lock(&module_mutex);
+	old = find_module_all(mod->name, strlen(mod->name), true);
+	if (old != NULL) {
+		if (old->state == MODULE_STATE_COMING
+		    || old->state == MODULE_STATE_UNFORMED) {
+			/* Wait in case it fails to load. */
+			mutex_unlock(&module_mutex);
+			err = wait_event_interruptible(module_wq,
+					       finished_loading(mod->name));
+			if (err)
+				goto out_unlocked;
+
+			/* The module might have gone in the meantime. */
+			mutex_lock(&module_mutex);
+			old = find_module_all(mod->name, strlen(mod->name),
+					      true);
+		}
+
+		/*
+		 * We are here only when the same module was being loaded. Do
+		 * not try to load it again right now. It prevents long delays
+		 * caused by serialized module load failures. It might happen
+		 * when more devices of the same type trigger load of
+		 * a particular module.
+		 */
+		if (old && old->state == MODULE_STATE_LIVE)
+			err = -EEXIST;
+		else
+			err = -EBUSY;
+		goto out;
+	}
+	mod_update_bounds(mod);
+	list_add_rcu(&mod->list, &modules);
+	mod_tree_insert(mod);
+	err = 0;
+
+out:
+	mutex_unlock(&module_mutex);
+out_unlocked:
+	return err;
+}
+
+static int complete_formation(struct module *mod, struct load_info *info)
+{
+	int err;
+
+	mutex_lock(&module_mutex);
+
+	/* Find duplicate symbols (must be called under lock). */
+	err = verify_exported_symbols(mod);
+	if (err < 0)
+		goto out;
+
+	/* These rely on module_mutex for list integrity. */
+	module_bug_finalize(info->hdr, info->sechdrs, mod);
+	module_cfi_finalize(info->hdr, info->sechdrs, mod);
+
+	if (module_check_misalignment(mod))
+		goto out_misaligned;
+
+	module_enable_ro(mod, false);
+	module_enable_nx(mod);
+	module_enable_x(mod);
+
+	/*
+	 * Mark state as coming so strong_try_module_get() ignores us,
+	 * but kallsyms etc. can see us.
+	 */
+	mod->state = MODULE_STATE_COMING;
+	mutex_unlock(&module_mutex);
+
+	return 0;
+
+out_misaligned:
+	err = -EINVAL;
+out:
+	mutex_unlock(&module_mutex);
+	return err;
+}
+
+static int prepare_coming_module(struct module *mod)
+{
+	int err;
+
+	ftrace_module_enable(mod);
+	err = klp_module_coming(mod);
+	if (err)
+		return err;
+
+	err = blocking_notifier_call_chain_robust(&module_notify_list,
+			MODULE_STATE_COMING, MODULE_STATE_GOING, mod);
+	err = notifier_to_errno(err);
+	if (err)
+		klp_module_going(mod);
+
+	return err;
+}
+
+static int unknown_module_param_cb(char *param, char *val, const char *modname,
+				   void *arg)
+{
+	struct module *mod = arg;
+	int ret;
+
+	if (strcmp(param, "async_probe") == 0) {
+		if (strtobool(val, &mod->async_probe_requested))
+			mod->async_probe_requested = true;
+		return 0;
+	}
+
+	/* Check for magic 'dyndbg' arg */
+	ret = ddebug_dyndbg_module_param_cb(param, val, modname);
+	if (ret != 0)
+		pr_warn("%s: unknown parameter '%s' ignored\n", modname, param);
+	return 0;
+}
+
+/*
+ * Allocate and load the module: note that size of section 0 is always
+ * zero, and we rely on this for optional sections.
+ */
+static int load_module(struct load_info *info, const char __user *uargs,
+		       int flags)
+{
+	struct module *mod;
+	long err = 0;
+	char *after_dashes;
+
+	/*
+	 * Do the signature check (if any) first. All that
+	 * the signature check needs is info->len, it does
+	 * not need any of the section info. That can be
+	 * set up later. This will minimize the chances
+	 * of a corrupt module causing problems before
+	 * we even get to the signature check.
+	 *
+	 * The check will also adjust info->len by stripping
+	 * off the sig length at the end of the module, making
+	 * checks against info->len more correct.
+	 */
+	err = module_sig_check(info, flags);
+	if (err)
+		goto free_copy;
+
+	/*
+	 * Do basic sanity checks against the ELF header and
+	 * sections.
+	 */
+	err = elf_validity_check(info);
+	if (err)
+		goto free_copy;
+
+	/*
+	 * Everything checks out, so set up the section info
+	 * in the info structure.
+	 */
+	err = setup_load_info(info, flags);
+	if (err)
+		goto free_copy;
+
+	/*
+	 * Now that we know we have the correct module name, check
+	 * if it's blacklisted.
+	 */
+	if (blacklisted(info->name)) {
+		err = -EPERM;
+		pr_err("Module %s is blacklisted\n", info->name);
+		goto free_copy;
+	}
+
+	err = rewrite_section_headers(info, flags);
+	if (err)
+		goto free_copy;
+
+	/* Check module struct version now, before we try to use module. */
+	if (!check_modstruct_version(info, info->mod)) {
+		err = -ENOEXEC;
+		goto free_copy;
+	}
+
+	/* Figure out module layout, and allocate all the memory. */
+	mod = layout_and_allocate(info, flags);
+	if (IS_ERR(mod)) {
+		err = PTR_ERR(mod);
+		goto free_copy;
+	}
+
+	audit_log_kern_module(mod->name);
+
+	/* Reserve our place in the list. */
+	err = add_unformed_module(mod);
+	if (err)
+		goto free_module;
+
+#ifdef CONFIG_MODULE_SIG
+	mod->sig_ok = info->sig_ok;
+	if (!mod->sig_ok) {
+		pr_notice_once("%s: module verification failed: signature "
+			       "and/or required key missing - tainting "
+			       "kernel\n", mod->name);
+		add_taint_module(mod, TAINT_UNSIGNED_MODULE, LOCKDEP_STILL_OK);
+	}
+#endif
+
+	/* To avoid stressing percpu allocator, do this once we're unique. */
+	err = percpu_modalloc(mod, info);
+	if (err)
+		goto unlink_mod;
+
+	/* Now module is in final location, initialize linked lists, etc. */
+	err = module_unload_init(mod);
+	if (err)
+		goto unlink_mod;
+
+	init_param_lock(mod);
+
+	/*
+	 * Now we've got everything in the final locations, we can
+	 * find optional sections.
+	 */
+	err = find_module_sections(mod, info);
+	if (err)
+		goto free_unload;
+
+	err = check_module_license_and_versions(mod);
+	if (err)
+		goto free_unload;
+
+	/* Set up MODINFO_ATTR fields */
+	setup_modinfo(mod, info);
+
+	/* Fix up syms, so that st_value is a pointer to location. */
+	err = simplify_symbols(mod, info);
+	if (err < 0)
+		goto free_modinfo;
+
+	err = apply_relocations(mod, info);
+	if (err < 0)
+		goto free_modinfo;
+
+	err = post_relocation(mod, info);
+	if (err < 0)
+		goto free_modinfo;
+
+	flush_module_icache(mod);
+
+	/* Now copy in args */
+	mod->args = strndup_user(uargs, ~0UL >> 1);
+	if (IS_ERR(mod->args)) {
+		err = PTR_ERR(mod->args);
+		goto free_arch_cleanup;
+	}
+
+	init_build_id(mod, info);
+	dynamic_debug_setup(mod, &info->dyndbg);
+
+	/* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
+	ftrace_module_init(mod);
+
+	/* Finally it's fully formed, ready to start executing. */
+	err = complete_formation(mod, info);
+	if (err)
+		goto ddebug_cleanup;
+
+	err = prepare_coming_module(mod);
+	if (err)
+		goto bug_cleanup;
+
+	mod->async_probe_requested = async_probe;
+
+	/* Module is ready to execute: parsing args may do that. */
+	after_dashes = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
+				  -32768, 32767, mod,
+				  unknown_module_param_cb);
+	if (IS_ERR(after_dashes)) {
+		err = PTR_ERR(after_dashes);
+		goto coming_cleanup;
+	} else if (after_dashes) {
+		pr_warn("%s: parameters '%s' after `--' ignored\n",
+		       mod->name, after_dashes);
+	}
+
+	/* Link in to sysfs. */
+	err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
+	if (err < 0)
+		goto coming_cleanup;
+
+	if (is_livepatch_module(mod)) {
+		err = copy_module_elf(mod, info);
+		if (err < 0)
+			goto sysfs_cleanup;
+	}
+
+	/* Get rid of temporary copy. */
+	free_copy(info, flags);
+
+	/* Done! */
+	trace_module_load(mod);
+
+	return do_init_module(mod);
+
+ sysfs_cleanup:
+	mod_sysfs_teardown(mod);
+ coming_cleanup:
+	mod->state = MODULE_STATE_GOING;
+	destroy_params(mod->kp, mod->num_kp);
+	blocking_notifier_call_chain(&module_notify_list,
+				     MODULE_STATE_GOING, mod);
+	klp_module_going(mod);
+ bug_cleanup:
+	mod->state = MODULE_STATE_GOING;
+	/* module_bug_cleanup needs module_mutex protection */
+	mutex_lock(&module_mutex);
+	module_bug_cleanup(mod);
+	mutex_unlock(&module_mutex);
+
+ ddebug_cleanup:
+	ftrace_release_mod(mod);
+	dynamic_debug_remove(mod, &info->dyndbg);
+	synchronize_rcu();
+	kfree(mod->args);
+ free_arch_cleanup:
+	module_arch_cleanup(mod);
+ free_modinfo:
+	free_modinfo(mod);
+ free_unload:
+	module_unload_free(mod);
+ unlink_mod:
+	mutex_lock(&module_mutex);
+	/* Unlink carefully: kallsyms could be walking list. */
+	list_del_rcu(&mod->list);
+	mod_tree_remove(mod);
+	wake_up_all(&module_wq);
+	/* Wait for RCU-sched synchronizing before releasing mod->list. */
+	synchronize_rcu();
+	mutex_unlock(&module_mutex);
+ free_module:
+	/* Free lock-classes; relies on the preceding sync_rcu() */
+	lockdep_free_key_range(mod->data_layout.base, mod->data_layout.size);
+
+	module_deallocate(mod, info);
+ free_copy:
+	free_copy(info, flags);
+	return err;
+}
+
+SYSCALL_DEFINE3(init_module, void __user *, umod,
+		unsigned long, len, const char __user *, uargs)
+{
+	int err;
+	struct load_info info = { };
+
+	err = may_init_module();
+	if (err)
+		return err;
+
+	pr_debug("init_module: umod=%p, len=%lu, uargs=%p\n",
+	       umod, len, uargs);
+
+	err = copy_module_from_user(umod, len, &info);
+	if (err)
+		return err;
+
+	return load_module(&info, uargs, 0);
+}
+
+SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
+{
+	struct load_info info = { };
+	void *buf = NULL;
+	int len;
+	int err;
+
+	err = may_init_module();
+	if (err)
+		return err;
+
+	pr_debug("finit_module: fd=%d, uargs=%p, flags=%i\n", fd, uargs, flags);
+
+	if (flags & ~(MODULE_INIT_IGNORE_MODVERSIONS
+		      |MODULE_INIT_IGNORE_VERMAGIC
+		      |MODULE_INIT_COMPRESSED_FILE))
+		return -EINVAL;
+
+	len = kernel_read_file_from_fd(fd, 0, &buf, INT_MAX, NULL,
+				       READING_MODULE);
+	if (len < 0)
+		return len;
+
+	if (flags & MODULE_INIT_COMPRESSED_FILE) {
+		err = module_decompress(&info, buf, len);
+		vfree(buf); /* compressed data is no longer needed */
+		if (err)
+			return err;
+	} else {
+		info.hdr = buf;
+		info.len = len;
+	}
+
+	return load_module(&info, uargs, flags);
+}
+
+static inline int within(unsigned long addr, void *start, unsigned long size)
+{
+	return ((void *)addr >= start && (void *)addr < start + size);
+}
+
+/* Keep in sync with MODULE_FLAGS_BUF_SIZE !!! */
+char *module_flags(struct module *mod, char *buf, bool show_state)
+{
+	int bx = 0;
+
+	BUG_ON(mod->state == MODULE_STATE_UNFORMED);
+	if (!mod->taints && !show_state)
+		goto out;
+	if (mod->taints ||
+	    mod->state == MODULE_STATE_GOING ||
+	    mod->state == MODULE_STATE_COMING) {
+		buf[bx++] = '(';
+		bx += module_flags_taint(mod->taints, buf + bx);
+		/* Show a - for module-is-being-unloaded */
+		if (mod->state == MODULE_STATE_GOING && show_state)
+			buf[bx++] = '-';
+		/* Show a + for module-is-being-loaded */
+		if (mod->state == MODULE_STATE_COMING && show_state)
+			buf[bx++] = '+';
+		buf[bx++] = ')';
+	}
+out:
+	buf[bx] = '\0';
+
+	return buf;
+}
+
+/* Given an address, look for it in the module exception tables. */
+const struct exception_table_entry *search_module_extables(unsigned long addr)
+{
+	const struct exception_table_entry *e = NULL;
+	struct module *mod;
+
+	preempt_disable();
+	mod = __module_address(addr);
+	if (!mod)
+		goto out;
+
+	if (!mod->num_exentries)
+		goto out;
+
+	e = search_extable(mod->extable,
+			   mod->num_exentries,
+			   addr);
+out:
+	preempt_enable();
+
+	/*
+	 * Now, if we found one, we are running inside it now, hence
+	 * we cannot unload the module, hence no refcnt needed.
+	 */
+	return e;
+}
+
+/**
+ * is_module_address() - is this address inside a module?
+ * @addr: the address to check.
+ *
+ * See is_module_text_address() if you simply want to see if the address
+ * is code (not data).
+ */
+bool is_module_address(unsigned long addr)
+{
+	bool ret;
+
+	preempt_disable();
+	ret = __module_address(addr) != NULL;
+	preempt_enable();
+
+	return ret;
+}
+
+/**
+ * __module_address() - get the module which contains an address.
+ * @addr: the address.
+ *
+ * Must be called with preempt disabled or module mutex held so that
+ * module doesn't get freed during this.
+ */
+struct module *__module_address(unsigned long addr)
+{
+	struct module *mod;
+	struct mod_tree_root *tree;
+
+	if (addr >= mod_tree.addr_min && addr <= mod_tree.addr_max)
+		tree = &mod_tree;
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+	else if (addr >= mod_data_tree.addr_min && addr <= mod_data_tree.addr_max)
+		tree = &mod_data_tree;
+#endif
+	else
+		return NULL;
+
+	module_assert_mutex_or_preempt();
+
+	mod = mod_find(addr, tree);
+	if (mod) {
+		BUG_ON(!within_module(addr, mod));
+		if (mod->state == MODULE_STATE_UNFORMED)
+			mod = NULL;
+	}
+	return mod;
+}
+
+/**
+ * is_module_text_address() - is this address inside module code?
+ * @addr: the address to check.
+ *
+ * See is_module_address() if you simply want to see if the address is
+ * anywhere in a module.  See kernel_text_address() for testing if an
+ * address corresponds to kernel or module code.
+ */
+bool is_module_text_address(unsigned long addr)
+{
+	bool ret;
+
+	preempt_disable();
+	ret = __module_text_address(addr) != NULL;
+	preempt_enable();
+
+	return ret;
+}
+
+/**
+ * __module_text_address() - get the module whose code contains an address.
+ * @addr: the address.
+ *
+ * Must be called with preempt disabled or module mutex held so that
+ * module doesn't get freed during this.
+ */
+struct module *__module_text_address(unsigned long addr)
+{
+	struct module *mod = __module_address(addr);
+	if (mod) {
+		/* Make sure it's within the text section. */
+		if (!within(addr, mod->init_layout.base, mod->init_layout.text_size)
+		    && !within(addr, mod->core_layout.base, mod->core_layout.text_size))
+			mod = NULL;
+	}
+	return mod;
+}
+
+/* Don't grab lock, we're oopsing. */
+void print_modules(void)
+{
+	struct module *mod;
+	char buf[MODULE_FLAGS_BUF_SIZE];
+
+	printk(KERN_DEFAULT "Modules linked in:");
+	/* Most callers should already have preempt disabled, but make sure */
+	preempt_disable();
+	list_for_each_entry_rcu(mod, &modules, list) {
+		if (mod->state == MODULE_STATE_UNFORMED)
+			continue;
+		pr_cont(" %s%s", mod->name, module_flags(mod, buf, true));
+	}
+
+	print_unloaded_tainted_modules();
+	preempt_enable();
+	if (last_unloaded_module.name[0])
+		pr_cont(" [last unloaded: %s%s]", last_unloaded_module.name,
+			last_unloaded_module.taints);
+	pr_cont("\n");
+}
diff --git a/kernel/module/procfs.c b/kernel/module/procfs.c
new file mode 100644
index 000000000..cf5b9f1e6
--- /dev/null
+++ b/kernel/module/procfs.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module proc support
+ *
+ * Copyright (C) 2008 Alexey Dobriyan
+ */
+
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/mutex.h>
+#include <linux/seq_file.h>
+#include <linux/proc_fs.h>
+#include "internal.h"
+
+#ifdef CONFIG_MODULE_UNLOAD
+static inline void print_unload_info(struct seq_file *m, struct module *mod)
+{
+	struct module_use *use;
+	int printed_something = 0;
+
+	seq_printf(m, " %i ", module_refcount(mod));
+
+	/*
+	 * Always include a trailing , so userspace can differentiate
+	 * between this and the old multi-field proc format.
+	 */
+	list_for_each_entry(use, &mod->source_list, source_list) {
+		printed_something = 1;
+		seq_printf(m, "%s,", use->source->name);
+	}
+
+	if (mod->init && !mod->exit) {
+		printed_something = 1;
+		seq_puts(m, "[permanent],");
+	}
+
+	if (!printed_something)
+		seq_puts(m, "-");
+}
+#else /* !CONFIG_MODULE_UNLOAD */
+static inline void print_unload_info(struct seq_file *m, struct module *mod)
+{
+	/* We don't know the usage count, or what modules are using. */
+	seq_puts(m, " - -");
+}
+#endif /* CONFIG_MODULE_UNLOAD */
+
+/* Called by the /proc file system to return a list of modules. */
+static void *m_start(struct seq_file *m, loff_t *pos)
+{
+	mutex_lock(&module_mutex);
+	return seq_list_start(&modules, *pos);
+}
+
+static void *m_next(struct seq_file *m, void *p, loff_t *pos)
+{
+	return seq_list_next(p, &modules, pos);
+}
+
+static void m_stop(struct seq_file *m, void *p)
+{
+	mutex_unlock(&module_mutex);
+}
+
+static int m_show(struct seq_file *m, void *p)
+{
+	struct module *mod = list_entry(p, struct module, list);
+	char buf[MODULE_FLAGS_BUF_SIZE];
+	void *value;
+	unsigned int size;
+
+	/* We always ignore unformed modules. */
+	if (mod->state == MODULE_STATE_UNFORMED)
+		return 0;
+
+	size = mod->init_layout.size + mod->core_layout.size;
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+	size += mod->data_layout.size;
+#endif
+	seq_printf(m, "%s %u", mod->name, size);
+	print_unload_info(m, mod);
+
+	/* Informative for users. */
+	seq_printf(m, " %s",
+		   mod->state == MODULE_STATE_GOING ? "Unloading" :
+		   mod->state == MODULE_STATE_COMING ? "Loading" :
+		   "Live");
+	/* Used by oprofile and other similar tools. */
+	value = m->private ? NULL : mod->core_layout.base;
+	seq_printf(m, " 0x%px", value);
+
+	/* Taints info */
+	if (mod->taints)
+		seq_printf(m, " %s", module_flags(mod, buf, true));
+
+	seq_puts(m, "\n");
+	return 0;
+}
+
+/*
+ * Format: modulename size refcount deps address
+ *
+ * Where refcount is a number or -, and deps is a comma-separated list
+ * of depends or -.
+ */
+static const struct seq_operations modules_op = {
+	.start	= m_start,
+	.next	= m_next,
+	.stop	= m_stop,
+	.show	= m_show
+};
+
+/*
+ * This also sets the "private" pointer to non-NULL if the
+ * kernel pointers should be hidden (so you can just test
+ * "m->private" to see if you should keep the values private).
+ *
+ * We use the same logic as for /proc/kallsyms.
+ */
+static int modules_open(struct inode *inode, struct file *file)
+{
+	int err = seq_open(file, &modules_op);
+
+	if (!err) {
+		struct seq_file *m = file->private_data;
+
+		m->private = kallsyms_show_value(file->f_cred) ? NULL : (void *)8ul;
+	}
+
+	return err;
+}
+
+static const struct proc_ops modules_proc_ops = {
+	.proc_flags	= PROC_ENTRY_PERMANENT,
+	.proc_open	= modules_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= seq_release,
+};
+
+static int __init proc_modules_init(void)
+{
+	proc_create("modules", 0, NULL, &modules_proc_ops);
+	return 0;
+}
+module_init(proc_modules_init);
diff --git a/kernel/module/signing.c b/kernel/module/signing.c
new file mode 100644
index 000000000..a2ff4242e
--- /dev/null
+++ b/kernel/module/signing.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Module signature checker
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/module_signature.h>
+#include <linux/string.h>
+#include <linux/verification.h>
+#include <linux/security.h>
+#include <crypto/public_key.h>
+#include <uapi/linux/module.h>
+#include "internal.h"
+
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX "module."
+
+static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
+module_param(sig_enforce, bool_enable_only, 0644);
+
+/*
+ * Export sig_enforce kernel cmdline parameter to allow other subsystems rely
+ * on that instead of directly to CONFIG_MODULE_SIG_FORCE config.
+ */
+bool is_module_sig_enforced(void)
+{
+	return sig_enforce;
+}
+EXPORT_SYMBOL(is_module_sig_enforced);
+
+void set_module_sig_enforced(void)
+{
+	sig_enforce = true;
+}
+
+/*
+ * Verify the signature on a module.
+ */
+int mod_verify_sig(const void *mod, struct load_info *info)
+{
+	struct module_signature ms;
+	size_t sig_len, modlen = info->len;
+	int ret;
+
+	pr_devel("==>%s(,%zu)\n", __func__, modlen);
+
+	if (modlen <= sizeof(ms))
+		return -EBADMSG;
+
+	memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms));
+
+	ret = mod_check_sig(&ms, modlen, "module");
+	if (ret)
+		return ret;
+
+	sig_len = be32_to_cpu(ms.sig_len);
+	modlen -= sig_len + sizeof(ms);
+	info->len = modlen;
+
+	return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
+				      VERIFY_USE_SECONDARY_KEYRING,
+				      VERIFYING_MODULE_SIGNATURE,
+				      NULL, NULL);
+}
+
+int module_sig_check(struct load_info *info, int flags)
+{
+	int err = -ENODATA;
+	const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
+	const char *reason;
+	const void *mod = info->hdr;
+	bool mangled_module = flags & (MODULE_INIT_IGNORE_MODVERSIONS |
+				       MODULE_INIT_IGNORE_VERMAGIC);
+	/*
+	 * Do not allow mangled modules as a module with version information
+	 * removed is no longer the module that was signed.
+	 */
+	if (!mangled_module &&
+	    info->len > markerlen &&
+	    memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
+		/* We truncate the module to discard the signature */
+		info->len -= markerlen;
+		err = mod_verify_sig(mod, info);
+		if (!err) {
+			info->sig_ok = true;
+			return 0;
+		}
+	}
+
+	/*
+	 * We don't permit modules to be loaded into the trusted kernels
+	 * without a valid signature on them, but if we're not enforcing,
+	 * certain errors are non-fatal.
+	 */
+	switch (err) {
+	case -ENODATA:
+		reason = "unsigned module";
+		break;
+	case -ENOPKG:
+		reason = "module with unsupported crypto";
+		break;
+	case -ENOKEY:
+		reason = "module with unavailable key";
+		break;
+
+	default:
+		/*
+		 * All other errors are fatal, including lack of memory,
+		 * unparseable signatures, and signature check failures --
+		 * even if signatures aren't required.
+		 */
+		return err;
+	}
+
+	if (is_module_sig_enforced()) {
+		pr_notice("Loading of %s is rejected\n", reason);
+		return -EKEYREJECTED;
+	}
+
+	return security_locked_down(LOCKDOWN_MODULE_SIGNATURE);
+}
diff --git a/kernel/module/strict_rwx.c b/kernel/module/strict_rwx.c
new file mode 100644
index 000000000..14fbea66f
--- /dev/null
+++ b/kernel/module/strict_rwx.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module strict rwx
+ *
+ * Copyright (C) 2015 Rusty Russell
+ */
+
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/set_memory.h>
+#include "internal.h"
+
+/*
+ * LKM RO/NX protection: protect module's text/ro-data
+ * from modification and any data from execution.
+ *
+ * General layout of module is:
+ *          [text] [read-only-data] [ro-after-init] [writable data]
+ * text_size -----^                ^               ^               ^
+ * ro_size ------------------------|               |               |
+ * ro_after_init_size -----------------------------|               |
+ * size -----------------------------------------------------------|
+ *
+ * These values are always page-aligned (as is base) when
+ * CONFIG_STRICT_MODULE_RWX is set.
+ */
+
+/*
+ * Since some arches are moving towards PAGE_KERNEL module allocations instead
+ * of PAGE_KERNEL_EXEC, keep frob_text() and module_enable_x() independent of
+ * CONFIG_STRICT_MODULE_RWX because they are needed regardless of whether we
+ * are strict.
+ */
+static void frob_text(const struct module_layout *layout,
+		      int (*set_memory)(unsigned long start, int num_pages))
+{
+	set_memory((unsigned long)layout->base,
+		   PAGE_ALIGN(layout->text_size) >> PAGE_SHIFT);
+}
+
+static void frob_rodata(const struct module_layout *layout,
+		 int (*set_memory)(unsigned long start, int num_pages))
+{
+	set_memory((unsigned long)layout->base + layout->text_size,
+		   (layout->ro_size - layout->text_size) >> PAGE_SHIFT);
+}
+
+static void frob_ro_after_init(const struct module_layout *layout,
+			int (*set_memory)(unsigned long start, int num_pages))
+{
+	set_memory((unsigned long)layout->base + layout->ro_size,
+		   (layout->ro_after_init_size - layout->ro_size) >> PAGE_SHIFT);
+}
+
+static void frob_writable_data(const struct module_layout *layout,
+			int (*set_memory)(unsigned long start, int num_pages))
+{
+	set_memory((unsigned long)layout->base + layout->ro_after_init_size,
+		   (layout->size - layout->ro_after_init_size) >> PAGE_SHIFT);
+}
+
+static bool layout_check_misalignment(const struct module_layout *layout)
+{
+	return WARN_ON(!PAGE_ALIGNED(layout->base)) ||
+	       WARN_ON(!PAGE_ALIGNED(layout->text_size)) ||
+	       WARN_ON(!PAGE_ALIGNED(layout->ro_size)) ||
+	       WARN_ON(!PAGE_ALIGNED(layout->ro_after_init_size)) ||
+	       WARN_ON(!PAGE_ALIGNED(layout->size));
+}
+
+bool module_check_misalignment(const struct module *mod)
+{
+	if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
+		return false;
+
+	return layout_check_misalignment(&mod->core_layout) ||
+	       layout_check_misalignment(&mod->data_layout) ||
+	       layout_check_misalignment(&mod->init_layout);
+}
+
+void module_enable_x(const struct module *mod)
+{
+	if (!PAGE_ALIGNED(mod->core_layout.base) ||
+	    !PAGE_ALIGNED(mod->init_layout.base))
+		return;
+
+	frob_text(&mod->core_layout, set_memory_x);
+	frob_text(&mod->init_layout, set_memory_x);
+}
+
+void module_enable_ro(const struct module *mod, bool after_init)
+{
+	if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
+		return;
+#ifdef CONFIG_STRICT_MODULE_RWX
+	if (!rodata_enabled)
+		return;
+#endif
+
+	set_vm_flush_reset_perms(mod->core_layout.base);
+	set_vm_flush_reset_perms(mod->init_layout.base);
+	frob_text(&mod->core_layout, set_memory_ro);
+
+	frob_rodata(&mod->data_layout, set_memory_ro);
+	frob_text(&mod->init_layout, set_memory_ro);
+	frob_rodata(&mod->init_layout, set_memory_ro);
+
+	if (after_init)
+		frob_ro_after_init(&mod->data_layout, set_memory_ro);
+}
+
+void module_enable_nx(const struct module *mod)
+{
+	if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
+		return;
+
+	frob_rodata(&mod->data_layout, set_memory_nx);
+	frob_ro_after_init(&mod->data_layout, set_memory_nx);
+	frob_writable_data(&mod->data_layout, set_memory_nx);
+	frob_rodata(&mod->init_layout, set_memory_nx);
+	frob_writable_data(&mod->init_layout, set_memory_nx);
+}
+
+int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+				char *secstrings, struct module *mod)
+{
+	const unsigned long shf_wx = SHF_WRITE | SHF_EXECINSTR;
+	int i;
+
+	if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
+		return 0;
+
+	for (i = 0; i < hdr->e_shnum; i++) {
+		if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) {
+			pr_err("%s: section %s (index %d) has invalid WRITE|EXEC flags\n",
+			       mod->name, secstrings + sechdrs[i].sh_name, i);
+			return -ENOEXEC;
+		}
+	}
+
+	return 0;
+}
diff --git a/kernel/module/sysfs.c b/kernel/module/sysfs.c
new file mode 100644
index 000000000..ce68f821d
--- /dev/null
+++ b/kernel/module/sysfs.c
@@ -0,0 +1,436 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module sysfs support
+ *
+ * Copyright (C) 2008 Rusty Russell
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/sysfs.h>
+#include <linux/slab.h>
+#include <linux/kallsyms.h>
+#include <linux/mutex.h>
+#include "internal.h"
+
+/*
+ * /sys/module/foo/sections stuff
+ * J. Corbet <corbet@lwn.net>
+ */
+#ifdef CONFIG_KALLSYMS
+struct module_sect_attr {
+	struct bin_attribute battr;
+	unsigned long address;
+};
+
+struct module_sect_attrs {
+	struct attribute_group grp;
+	unsigned int nsections;
+	struct module_sect_attr attrs[];
+};
+
+#define MODULE_SECT_READ_SIZE (3 /* "0x", "\n" */ + (BITS_PER_LONG / 4))
+static ssize_t module_sect_read(struct file *file, struct kobject *kobj,
+				struct bin_attribute *battr,
+				char *buf, loff_t pos, size_t count)
+{
+	struct module_sect_attr *sattr =
+		container_of(battr, struct module_sect_attr, battr);
+	char bounce[MODULE_SECT_READ_SIZE + 1];
+	size_t wrote;
+
+	if (pos != 0)
+		return -EINVAL;
+
+	/*
+	 * Since we're a binary read handler, we must account for the
+	 * trailing NUL byte that sprintf will write: if "buf" is
+	 * too small to hold the NUL, or the NUL is exactly the last
+	 * byte, the read will look like it got truncated by one byte.
+	 * Since there is no way to ask sprintf nicely to not write
+	 * the NUL, we have to use a bounce buffer.
+	 */
+	wrote = scnprintf(bounce, sizeof(bounce), "0x%px\n",
+			  kallsyms_show_value(file->f_cred)
+				? (void *)sattr->address : NULL);
+	count = min(count, wrote);
+	memcpy(buf, bounce, count);
+
+	return count;
+}
+
+static void free_sect_attrs(struct module_sect_attrs *sect_attrs)
+{
+	unsigned int section;
+
+	for (section = 0; section < sect_attrs->nsections; section++)
+		kfree(sect_attrs->attrs[section].battr.attr.name);
+	kfree(sect_attrs);
+}
+
+static void add_sect_attrs(struct module *mod, const struct load_info *info)
+{
+	unsigned int nloaded = 0, i, size[2];
+	struct module_sect_attrs *sect_attrs;
+	struct module_sect_attr *sattr;
+	struct bin_attribute **gattr;
+
+	/* Count loaded sections and allocate structures */
+	for (i = 0; i < info->hdr->e_shnum; i++)
+		if (!sect_empty(&info->sechdrs[i]))
+			nloaded++;
+	size[0] = ALIGN(struct_size(sect_attrs, attrs, nloaded),
+			sizeof(sect_attrs->grp.bin_attrs[0]));
+	size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.bin_attrs[0]);
+	sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL);
+	if (!sect_attrs)
+		return;
+
+	/* Setup section attributes. */
+	sect_attrs->grp.name = "sections";
+	sect_attrs->grp.bin_attrs = (void *)sect_attrs + size[0];
+
+	sect_attrs->nsections = 0;
+	sattr = &sect_attrs->attrs[0];
+	gattr = &sect_attrs->grp.bin_attrs[0];
+	for (i = 0; i < info->hdr->e_shnum; i++) {
+		Elf_Shdr *sec = &info->sechdrs[i];
+
+		if (sect_empty(sec))
+			continue;
+		sysfs_bin_attr_init(&sattr->battr);
+		sattr->address = sec->sh_addr;
+		sattr->battr.attr.name =
+			kstrdup(info->secstrings + sec->sh_name, GFP_KERNEL);
+		if (!sattr->battr.attr.name)
+			goto out;
+		sect_attrs->nsections++;
+		sattr->battr.read = module_sect_read;
+		sattr->battr.size = MODULE_SECT_READ_SIZE;
+		sattr->battr.attr.mode = 0400;
+		*(gattr++) = &(sattr++)->battr;
+	}
+	*gattr = NULL;
+
+	if (sysfs_create_group(&mod->mkobj.kobj, &sect_attrs->grp))
+		goto out;
+
+	mod->sect_attrs = sect_attrs;
+	return;
+out:
+	free_sect_attrs(sect_attrs);
+}
+
+static void remove_sect_attrs(struct module *mod)
+{
+	if (mod->sect_attrs) {
+		sysfs_remove_group(&mod->mkobj.kobj,
+				   &mod->sect_attrs->grp);
+		/*
+		 * We are positive that no one is using any sect attrs
+		 * at this point.  Deallocate immediately.
+		 */
+		free_sect_attrs(mod->sect_attrs);
+		mod->sect_attrs = NULL;
+	}
+}
+
+/*
+ * /sys/module/foo/notes/.section.name gives contents of SHT_NOTE sections.
+ */
+
+struct module_notes_attrs {
+	struct kobject *dir;
+	unsigned int notes;
+	struct bin_attribute attrs[];
+};
+
+static ssize_t module_notes_read(struct file *filp, struct kobject *kobj,
+				 struct bin_attribute *bin_attr,
+				 char *buf, loff_t pos, size_t count)
+{
+	/*
+	 * The caller checked the pos and count against our size.
+	 */
+	memcpy(buf, bin_attr->private + pos, count);
+	return count;
+}
+
+static void free_notes_attrs(struct module_notes_attrs *notes_attrs,
+			     unsigned int i)
+{
+	if (notes_attrs->dir) {
+		while (i-- > 0)
+			sysfs_remove_bin_file(notes_attrs->dir,
+					      &notes_attrs->attrs[i]);
+		kobject_put(notes_attrs->dir);
+	}
+	kfree(notes_attrs);
+}
+
+static void add_notes_attrs(struct module *mod, const struct load_info *info)
+{
+	unsigned int notes, loaded, i;
+	struct module_notes_attrs *notes_attrs;
+	struct bin_attribute *nattr;
+
+	/* failed to create section attributes, so can't create notes */
+	if (!mod->sect_attrs)
+		return;
+
+	/* Count notes sections and allocate structures.  */
+	notes = 0;
+	for (i = 0; i < info->hdr->e_shnum; i++)
+		if (!sect_empty(&info->sechdrs[i]) &&
+		    info->sechdrs[i].sh_type == SHT_NOTE)
+			++notes;
+
+	if (notes == 0)
+		return;
+
+	notes_attrs = kzalloc(struct_size(notes_attrs, attrs, notes),
+			      GFP_KERNEL);
+	if (!notes_attrs)
+		return;
+
+	notes_attrs->notes = notes;
+	nattr = &notes_attrs->attrs[0];
+	for (loaded = i = 0; i < info->hdr->e_shnum; ++i) {
+		if (sect_empty(&info->sechdrs[i]))
+			continue;
+		if (info->sechdrs[i].sh_type == SHT_NOTE) {
+			sysfs_bin_attr_init(nattr);
+			nattr->attr.name = mod->sect_attrs->attrs[loaded].battr.attr.name;
+			nattr->attr.mode = 0444;
+			nattr->size = info->sechdrs[i].sh_size;
+			nattr->private = (void *)info->sechdrs[i].sh_addr;
+			nattr->read = module_notes_read;
+			++nattr;
+		}
+		++loaded;
+	}
+
+	notes_attrs->dir = kobject_create_and_add("notes", &mod->mkobj.kobj);
+	if (!notes_attrs->dir)
+		goto out;
+
+	for (i = 0; i < notes; ++i)
+		if (sysfs_create_bin_file(notes_attrs->dir,
+					  &notes_attrs->attrs[i]))
+			goto out;
+
+	mod->notes_attrs = notes_attrs;
+	return;
+
+out:
+	free_notes_attrs(notes_attrs, i);
+}
+
+static void remove_notes_attrs(struct module *mod)
+{
+	if (mod->notes_attrs)
+		free_notes_attrs(mod->notes_attrs, mod->notes_attrs->notes);
+}
+
+#else /* !CONFIG_KALLSYMS */
+static inline void add_sect_attrs(struct module *mod, const struct load_info *info) { }
+static inline void remove_sect_attrs(struct module *mod) { }
+static inline void add_notes_attrs(struct module *mod, const struct load_info *info) { }
+static inline void remove_notes_attrs(struct module *mod) { }
+#endif /* CONFIG_KALLSYMS */
+
+static void del_usage_links(struct module *mod)
+{
+#ifdef CONFIG_MODULE_UNLOAD
+	struct module_use *use;
+
+	mutex_lock(&module_mutex);
+	list_for_each_entry(use, &mod->target_list, target_list)
+		sysfs_remove_link(use->target->holders_dir, mod->name);
+	mutex_unlock(&module_mutex);
+#endif
+}
+
+static int add_usage_links(struct module *mod)
+{
+	int ret = 0;
+#ifdef CONFIG_MODULE_UNLOAD
+	struct module_use *use;
+
+	mutex_lock(&module_mutex);
+	list_for_each_entry(use, &mod->target_list, target_list) {
+		ret = sysfs_create_link(use->target->holders_dir,
+					&mod->mkobj.kobj, mod->name);
+		if (ret)
+			break;
+	}
+	mutex_unlock(&module_mutex);
+	if (ret)
+		del_usage_links(mod);
+#endif
+	return ret;
+}
+
+static void module_remove_modinfo_attrs(struct module *mod, int end)
+{
+	struct module_attribute *attr;
+	int i;
+
+	for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) {
+		if (end >= 0 && i > end)
+			break;
+		/* pick a field to test for end of list */
+		if (!attr->attr.name)
+			break;
+		sysfs_remove_file(&mod->mkobj.kobj, &attr->attr);
+		if (attr->free)
+			attr->free(mod);
+	}
+	kfree(mod->modinfo_attrs);
+}
+
+static int module_add_modinfo_attrs(struct module *mod)
+{
+	struct module_attribute *attr;
+	struct module_attribute *temp_attr;
+	int error = 0;
+	int i;
+
+	mod->modinfo_attrs = kzalloc((sizeof(struct module_attribute) *
+					(modinfo_attrs_count + 1)),
+					GFP_KERNEL);
+	if (!mod->modinfo_attrs)
+		return -ENOMEM;
+
+	temp_attr = mod->modinfo_attrs;
+	for (i = 0; (attr = modinfo_attrs[i]); i++) {
+		if (!attr->test || attr->test(mod)) {
+			memcpy(temp_attr, attr, sizeof(*temp_attr));
+			sysfs_attr_init(&temp_attr->attr);
+			error = sysfs_create_file(&mod->mkobj.kobj,
+						  &temp_attr->attr);
+			if (error)
+				goto error_out;
+			++temp_attr;
+		}
+	}
+
+	return 0;
+
+error_out:
+	if (i > 0)
+		module_remove_modinfo_attrs(mod, --i);
+	else
+		kfree(mod->modinfo_attrs);
+	return error;
+}
+
+static void mod_kobject_put(struct module *mod)
+{
+	DECLARE_COMPLETION_ONSTACK(c);
+
+	mod->mkobj.kobj_completion = &c;
+	kobject_put(&mod->mkobj.kobj);
+	wait_for_completion(&c);
+}
+
+static int mod_sysfs_init(struct module *mod)
+{
+	int err;
+	struct kobject *kobj;
+
+	if (!module_sysfs_initialized) {
+		pr_err("%s: module sysfs not initialized\n", mod->name);
+		err = -EINVAL;
+		goto out;
+	}
+
+	kobj = kset_find_obj(module_kset, mod->name);
+	if (kobj) {
+		pr_err("%s: module is already loaded\n", mod->name);
+		kobject_put(kobj);
+		err = -EINVAL;
+		goto out;
+	}
+
+	mod->mkobj.mod = mod;
+
+	memset(&mod->mkobj.kobj, 0, sizeof(mod->mkobj.kobj));
+	mod->mkobj.kobj.kset = module_kset;
+	err = kobject_init_and_add(&mod->mkobj.kobj, &module_ktype, NULL,
+				   "%s", mod->name);
+	if (err)
+		mod_kobject_put(mod);
+
+out:
+	return err;
+}
+
+int mod_sysfs_setup(struct module *mod,
+		    const struct load_info *info,
+			   struct kernel_param *kparam,
+			   unsigned int num_params)
+{
+	int err;
+
+	err = mod_sysfs_init(mod);
+	if (err)
+		goto out;
+
+	mod->holders_dir = kobject_create_and_add("holders", &mod->mkobj.kobj);
+	if (!mod->holders_dir) {
+		err = -ENOMEM;
+		goto out_unreg;
+	}
+
+	err = module_param_sysfs_setup(mod, kparam, num_params);
+	if (err)
+		goto out_unreg_holders;
+
+	err = module_add_modinfo_attrs(mod);
+	if (err)
+		goto out_unreg_param;
+
+	err = add_usage_links(mod);
+	if (err)
+		goto out_unreg_modinfo_attrs;
+
+	add_sect_attrs(mod, info);
+	add_notes_attrs(mod, info);
+
+	return 0;
+
+out_unreg_modinfo_attrs:
+	module_remove_modinfo_attrs(mod, -1);
+out_unreg_param:
+	module_param_sysfs_remove(mod);
+out_unreg_holders:
+	kobject_put(mod->holders_dir);
+out_unreg:
+	mod_kobject_put(mod);
+out:
+	return err;
+}
+
+static void mod_sysfs_fini(struct module *mod)
+{
+	remove_notes_attrs(mod);
+	remove_sect_attrs(mod);
+	mod_kobject_put(mod);
+}
+
+void mod_sysfs_teardown(struct module *mod)
+{
+	del_usage_links(mod);
+	module_remove_modinfo_attrs(mod, -1);
+	module_param_sysfs_remove(mod);
+	kobject_put(mod->mkobj.drivers_dir);
+	kobject_put(mod->holders_dir);
+	mod_sysfs_fini(mod);
+}
+
+void init_param_lock(struct module *mod)
+{
+	mutex_init(&mod->param_lock);
+}
diff --git a/kernel/module/tracking.c b/kernel/module/tracking.c
new file mode 100644
index 000000000..26d812e07
--- /dev/null
+++ b/kernel/module/tracking.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module taint unload tracking support
+ *
+ * Copyright (C) 2022 Aaron Tomlin
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/debugfs.h>
+#include <linux/rculist.h>
+#include "internal.h"
+
+static LIST_HEAD(unloaded_tainted_modules);
+
+int try_add_tainted_module(struct module *mod)
+{
+	struct mod_unload_taint *mod_taint;
+
+	module_assert_mutex_or_preempt();
+
+	if (!mod->taints)
+		goto out;
+
+	list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules, list,
+				lockdep_is_held(&module_mutex)) {
+		if (!strcmp(mod_taint->name, mod->name) &&
+		    mod_taint->taints & mod->taints) {
+			mod_taint->count++;
+			goto out;
+		}
+	}
+
+	mod_taint = kmalloc(sizeof(*mod_taint), GFP_KERNEL);
+	if (unlikely(!mod_taint))
+		return -ENOMEM;
+	strscpy(mod_taint->name, mod->name, MODULE_NAME_LEN);
+	mod_taint->taints = mod->taints;
+	list_add_rcu(&mod_taint->list, &unloaded_tainted_modules);
+	mod_taint->count = 1;
+out:
+	return 0;
+}
+
+void print_unloaded_tainted_modules(void)
+{
+	struct mod_unload_taint *mod_taint;
+	char buf[MODULE_FLAGS_BUF_SIZE];
+
+	if (!list_empty(&unloaded_tainted_modules)) {
+		printk(KERN_DEFAULT "Unloaded tainted modules:");
+		list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules,
+					list) {
+			size_t l;
+
+			l = module_flags_taint(mod_taint->taints, buf);
+			buf[l++] = '\0';
+			pr_cont(" %s(%s):%llu", mod_taint->name, buf,
+				mod_taint->count);
+		}
+	}
+}
+
+#ifdef CONFIG_DEBUG_FS
+static void *unloaded_tainted_modules_seq_start(struct seq_file *m, loff_t *pos)
+	__acquires(rcu)
+{
+	rcu_read_lock();
+	return seq_list_start_rcu(&unloaded_tainted_modules, *pos);
+}
+
+static void *unloaded_tainted_modules_seq_next(struct seq_file *m, void *p, loff_t *pos)
+{
+	return seq_list_next_rcu(p, &unloaded_tainted_modules, pos);
+}
+
+static void unloaded_tainted_modules_seq_stop(struct seq_file *m, void *p)
+	__releases(rcu)
+{
+	rcu_read_unlock();
+}
+
+static int unloaded_tainted_modules_seq_show(struct seq_file *m, void *p)
+{
+	struct mod_unload_taint *mod_taint;
+	char buf[MODULE_FLAGS_BUF_SIZE];
+	size_t l;
+
+	mod_taint = list_entry(p, struct mod_unload_taint, list);
+	l = module_flags_taint(mod_taint->taints, buf);
+	buf[l++] = '\0';
+
+	seq_printf(m, "%s (%s) %llu", mod_taint->name, buf, mod_taint->count);
+	seq_puts(m, "\n");
+
+	return 0;
+}
+
+static const struct seq_operations unloaded_tainted_modules_seq_ops = {
+	.start = unloaded_tainted_modules_seq_start,
+	.next  = unloaded_tainted_modules_seq_next,
+	.stop  = unloaded_tainted_modules_seq_stop,
+	.show  = unloaded_tainted_modules_seq_show,
+};
+
+static int unloaded_tainted_modules_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &unloaded_tainted_modules_seq_ops);
+}
+
+static const struct file_operations unloaded_tainted_modules_fops = {
+	.open = unloaded_tainted_modules_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+static int __init unloaded_tainted_modules_init(void)
+{
+	struct dentry *dir;
+
+	dir = debugfs_create_dir("modules", NULL);
+	debugfs_create_file("unloaded_tainted", 0444, dir, NULL,
+			    &unloaded_tainted_modules_fops);
+
+	return 0;
+}
+module_init(unloaded_tainted_modules_init);
+#endif /* CONFIG_DEBUG_FS */
diff --git a/kernel/module/tree_lookup.c b/kernel/module/tree_lookup.c
new file mode 100644
index 000000000..8ec5cfd60
--- /dev/null
+++ b/kernel/module/tree_lookup.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Modules tree lookup
+ *
+ * Copyright (C) 2015 Peter Zijlstra
+ * Copyright (C) 2015 Rusty Russell
+ */
+
+#include <linux/module.h>
+#include <linux/rbtree_latch.h>
+#include "internal.h"
+
+/*
+ * Use a latched RB-tree for __module_address(); this allows us to use
+ * RCU-sched lookups of the address from any context.
+ *
+ * This is conditional on PERF_EVENTS || TRACING because those can really hit
+ * __module_address() hard by doing a lot of stack unwinding; potentially from
+ * NMI context.
+ */
+
+static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n)
+{
+	struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
+
+	return (unsigned long)layout->base;
+}
+
+static __always_inline unsigned long __mod_tree_size(struct latch_tree_node *n)
+{
+	struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
+
+	return (unsigned long)layout->size;
+}
+
+static __always_inline bool
+mod_tree_less(struct latch_tree_node *a, struct latch_tree_node *b)
+{
+	return __mod_tree_val(a) < __mod_tree_val(b);
+}
+
+static __always_inline int
+mod_tree_comp(void *key, struct latch_tree_node *n)
+{
+	unsigned long val = (unsigned long)key;
+	unsigned long start, end;
+
+	start = __mod_tree_val(n);
+	if (val < start)
+		return -1;
+
+	end = start + __mod_tree_size(n);
+	if (val >= end)
+		return 1;
+
+	return 0;
+}
+
+static const struct latch_tree_ops mod_tree_ops = {
+	.less = mod_tree_less,
+	.comp = mod_tree_comp,
+};
+
+static noinline void __mod_tree_insert(struct mod_tree_node *node, struct mod_tree_root *tree)
+{
+	latch_tree_insert(&node->node, &tree->root, &mod_tree_ops);
+}
+
+static void __mod_tree_remove(struct mod_tree_node *node, struct mod_tree_root *tree)
+{
+	latch_tree_erase(&node->node, &tree->root, &mod_tree_ops);
+}
+
+/*
+ * These modifications: insert, remove_init and remove; are serialized by the
+ * module_mutex.
+ */
+void mod_tree_insert(struct module *mod)
+{
+	mod->core_layout.mtn.mod = mod;
+	mod->init_layout.mtn.mod = mod;
+
+	__mod_tree_insert(&mod->core_layout.mtn, &mod_tree);
+	if (mod->init_layout.size)
+		__mod_tree_insert(&mod->init_layout.mtn, &mod_tree);
+
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+	mod->data_layout.mtn.mod = mod;
+	__mod_tree_insert(&mod->data_layout.mtn, &mod_data_tree);
+#endif
+}
+
+void mod_tree_remove_init(struct module *mod)
+{
+	if (mod->init_layout.size)
+		__mod_tree_remove(&mod->init_layout.mtn, &mod_tree);
+}
+
+void mod_tree_remove(struct module *mod)
+{
+	__mod_tree_remove(&mod->core_layout.mtn, &mod_tree);
+	mod_tree_remove_init(mod);
+#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
+	__mod_tree_remove(&mod->data_layout.mtn, &mod_data_tree);
+#endif
+}
+
+struct module *mod_find(unsigned long addr, struct mod_tree_root *tree)
+{
+	struct latch_tree_node *ltn;
+
+	ltn = latch_tree_find((void *)addr, &tree->root, &mod_tree_ops);
+	if (!ltn)
+		return NULL;
+
+	return container_of(ltn, struct mod_tree_node, node)->mod;
+}
diff --git a/kernel/module/version.c b/kernel/module/version.c
new file mode 100644
index 000000000..53f43ac5a
--- /dev/null
+++ b/kernel/module/version.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module version support
+ *
+ * Copyright (C) 2008 Rusty Russell
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/printk.h>
+#include "internal.h"
+
+int check_version(const struct load_info *info,
+		  const char *symname,
+			 struct module *mod,
+			 const s32 *crc)
+{
+	Elf_Shdr *sechdrs = info->sechdrs;
+	unsigned int versindex = info->index.vers;
+	unsigned int i, num_versions;
+	struct modversion_info *versions;
+
+	/* Exporting module didn't supply crcs?  OK, we're already tainted. */
+	if (!crc)
+		return 1;
+
+	/* No versions at all?  modprobe --force does this. */
+	if (versindex == 0)
+		return try_to_force_load(mod, symname) == 0;
+
+	versions = (void *)sechdrs[versindex].sh_addr;
+	num_versions = sechdrs[versindex].sh_size
+		/ sizeof(struct modversion_info);
+
+	for (i = 0; i < num_versions; i++) {
+		u32 crcval;
+
+		if (strcmp(versions[i].name, symname) != 0)
+			continue;
+
+		crcval = *crc;
+		if (versions[i].crc == crcval)
+			return 1;
+		pr_debug("Found checksum %X vs module %lX\n",
+			 crcval, versions[i].crc);
+		goto bad_version;
+	}
+
+	/* Broken toolchain. Warn once, then let it go.. */
+	pr_warn_once("%s: no symbol version for %s\n", info->name, symname);
+	return 1;
+
+bad_version:
+	pr_warn("%s: disagrees about version of symbol %s\n", info->name, symname);
+	return 0;
+}
+
+int check_modstruct_version(const struct load_info *info,
+			    struct module *mod)
+{
+	struct find_symbol_arg fsa = {
+		.name	= "module_layout",
+		.gplok	= true,
+	};
+
+	/*
+	 * Since this should be found in kernel (which can't be removed), no
+	 * locking is necessary -- use preempt_disable() to placate lockdep.
+	 */
+	preempt_disable();
+	if (!find_symbol(&fsa)) {
+		preempt_enable();
+		BUG();
+	}
+	preempt_enable();
+	return check_version(info, "module_layout", mod, fsa.crc);
+}
+
+/* First part is kernel version, which we ignore if module has crcs. */
+int same_magic(const char *amagic, const char *bmagic,
+	       bool has_crcs)
+{
+	if (has_crcs) {
+		amagic += strcspn(amagic, " ");
+		bmagic += strcspn(bmagic, " ");
+	}
+	return strcmp(amagic, bmagic) == 0;
+}
+
+/*
+ * Generate the signature for all relevant module structures here.
+ * If these change, we don't want to try to parse the module.
+ */
+void module_layout(struct module *mod,
+		   struct modversion_info *ver,
+		   struct kernel_param *kp,
+		   struct kernel_symbol *ks,
+		   struct tracepoint * const *tp)
+{
+}
+EXPORT_SYMBOL(module_layout);
diff --git a/kernel/module_signature.c b/kernel/module_signature.c
new file mode 100644
index 000000000..00132d124
--- /dev/null
+++ b/kernel/module_signature.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Module signature checker
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/errno.h>
+#include <linux/printk.h>
+#include <linux/module_signature.h>
+#include <asm/byteorder.h>
+
+/**
+ * mod_check_sig - check that the given signature is sane
+ *
+ * @ms:		Signature to check.
+ * @file_len:	Size of the file to which @ms is appended.
+ * @name:	What is being checked. Used for error messages.
+ */
+int mod_check_sig(const struct module_signature *ms, size_t file_len,
+		  const char *name)
+{
+	if (be32_to_cpu(ms->sig_len) >= file_len - sizeof(*ms))
+		return -EBADMSG;
+
+	if (ms->id_type != PKEY_ID_PKCS7) {
+		pr_err("%s: not signed with expected PKCS#7 message\n",
+		       name);
+		return -ENOPKG;
+	}
+
+	if (ms->algo != 0 ||
+	    ms->hash != 0 ||
+	    ms->signer_len != 0 ||
+	    ms->key_id_len != 0 ||
+	    ms->__pad[0] != 0 ||
+	    ms->__pad[1] != 0 ||
+	    ms->__pad[2] != 0) {
+		pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n",
+		       name);
+		return -EBADMSG;
+	}
+
+	return 0;
+}
diff --git a/kernel/notifier.c b/kernel/notifier.c
new file mode 100644
index 000000000..0d5bd62c4
--- /dev/null
+++ b/kernel/notifier.c
@@ -0,0 +1,607 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kdebug.h>
+#include <linux/kprobes.h>
+#include <linux/export.h>
+#include <linux/notifier.h>
+#include <linux/rcupdate.h>
+#include <linux/vmalloc.h>
+#include <linux/reboot.h>
+
+/*
+ *	Notifier list for kernel code which wants to be called
+ *	at shutdown. This is used to stop any idling DMA operations
+ *	and the like.
+ */
+BLOCKING_NOTIFIER_HEAD(reboot_notifier_list);
+
+/*
+ *	Notifier chain core routines.  The exported routines below
+ *	are layered on top of these, with appropriate locking added.
+ */
+
+static int notifier_chain_register(struct notifier_block **nl,
+				   struct notifier_block *n,
+				   bool unique_priority)
+{
+	while ((*nl) != NULL) {
+		if (unlikely((*nl) == n)) {
+			WARN(1, "notifier callback %ps already registered",
+			     n->notifier_call);
+			return -EEXIST;
+		}
+		if (n->priority > (*nl)->priority)
+			break;
+		if (n->priority == (*nl)->priority && unique_priority)
+			return -EBUSY;
+		nl = &((*nl)->next);
+	}
+	n->next = *nl;
+	rcu_assign_pointer(*nl, n);
+	return 0;
+}
+
+static int notifier_chain_unregister(struct notifier_block **nl,
+		struct notifier_block *n)
+{
+	while ((*nl) != NULL) {
+		if ((*nl) == n) {
+			rcu_assign_pointer(*nl, n->next);
+			return 0;
+		}
+		nl = &((*nl)->next);
+	}
+	return -ENOENT;
+}
+
+/**
+ * notifier_call_chain - Informs the registered notifiers about an event.
+ *	@nl:		Pointer to head of the blocking notifier chain
+ *	@val:		Value passed unmodified to notifier function
+ *	@v:		Pointer passed unmodified to notifier function
+ *	@nr_to_call:	Number of notifier functions to be called. Don't care
+ *			value of this parameter is -1.
+ *	@nr_calls:	Records the number of notifications sent. Don't care
+ *			value of this field is NULL.
+ *	@returns:	notifier_call_chain returns the value returned by the
+ *			last notifier function called.
+ */
+static int notifier_call_chain(struct notifier_block **nl,
+			       unsigned long val, void *v,
+			       int nr_to_call, int *nr_calls)
+{
+	int ret = NOTIFY_DONE;
+	struct notifier_block *nb, *next_nb;
+
+	nb = rcu_dereference_raw(*nl);
+
+	while (nb && nr_to_call) {
+		next_nb = rcu_dereference_raw(nb->next);
+
+#ifdef CONFIG_DEBUG_NOTIFIERS
+		if (unlikely(!func_ptr_is_kernel_text(nb->notifier_call))) {
+			WARN(1, "Invalid notifier called!");
+			nb = next_nb;
+			continue;
+		}
+#endif
+		ret = nb->notifier_call(nb, val, v);
+
+		if (nr_calls)
+			(*nr_calls)++;
+
+		if (ret & NOTIFY_STOP_MASK)
+			break;
+		nb = next_nb;
+		nr_to_call--;
+	}
+	return ret;
+}
+NOKPROBE_SYMBOL(notifier_call_chain);
+
+/**
+ * notifier_call_chain_robust - Inform the registered notifiers about an event
+ *                              and rollback on error.
+ * @nl:		Pointer to head of the blocking notifier chain
+ * @val_up:	Value passed unmodified to the notifier function
+ * @val_down:	Value passed unmodified to the notifier function when recovering
+ *              from an error on @val_up
+ * @v		Pointer passed unmodified to the notifier function
+ *
+ * NOTE:	It is important the @nl chain doesn't change between the two
+ *		invocations of notifier_call_chain() such that we visit the
+ *		exact same notifier callbacks; this rules out any RCU usage.
+ *
+ * Returns:	the return value of the @val_up call.
+ */
+static int notifier_call_chain_robust(struct notifier_block **nl,
+				     unsigned long val_up, unsigned long val_down,
+				     void *v)
+{
+	int ret, nr = 0;
+
+	ret = notifier_call_chain(nl, val_up, v, -1, &nr);
+	if (ret & NOTIFY_STOP_MASK)
+		notifier_call_chain(nl, val_down, v, nr-1, NULL);
+
+	return ret;
+}
+
+/*
+ *	Atomic notifier chain routines.  Registration and unregistration
+ *	use a spinlock, and call_chain is synchronized by RCU (no locks).
+ */
+
+/**
+ *	atomic_notifier_chain_register - Add notifier to an atomic notifier chain
+ *	@nh: Pointer to head of the atomic notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to an atomic notifier chain.
+ *
+ *	Returns 0 on success, %-EEXIST on error.
+ */
+int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
+		struct notifier_block *n)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_register(&nh->head, n, false);
+	spin_unlock_irqrestore(&nh->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_chain_register);
+
+/**
+ *	atomic_notifier_chain_register_unique_prio - Add notifier to an atomic notifier chain
+ *	@nh: Pointer to head of the atomic notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to an atomic notifier chain if there is no other
+ *	notifier registered using the same priority.
+ *
+ *	Returns 0 on success, %-EEXIST or %-EBUSY on error.
+ */
+int atomic_notifier_chain_register_unique_prio(struct atomic_notifier_head *nh,
+					       struct notifier_block *n)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_register(&nh->head, n, true);
+	spin_unlock_irqrestore(&nh->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_chain_register_unique_prio);
+
+/**
+ *	atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain
+ *	@nh: Pointer to head of the atomic notifier chain
+ *	@n: Entry to remove from notifier chain
+ *
+ *	Removes a notifier from an atomic notifier chain.
+ *
+ *	Returns zero on success or %-ENOENT on failure.
+ */
+int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
+		struct notifier_block *n)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_unregister(&nh->head, n);
+	spin_unlock_irqrestore(&nh->lock, flags);
+	synchronize_rcu();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister);
+
+/**
+ *	atomic_notifier_call_chain - Call functions in an atomic notifier chain
+ *	@nh: Pointer to head of the atomic notifier chain
+ *	@val: Value passed unmodified to notifier function
+ *	@v: Pointer passed unmodified to notifier function
+ *
+ *	Calls each function in a notifier chain in turn.  The functions
+ *	run in an atomic context, so they must not block.
+ *	This routine uses RCU to synchronize with changes to the chain.
+ *
+ *	If the return value of the notifier can be and'ed
+ *	with %NOTIFY_STOP_MASK then atomic_notifier_call_chain()
+ *	will return immediately, with the return value of
+ *	the notifier function which halted execution.
+ *	Otherwise the return value is the return value
+ *	of the last notifier function called.
+ */
+int atomic_notifier_call_chain(struct atomic_notifier_head *nh,
+			       unsigned long val, void *v)
+{
+	int ret;
+
+	rcu_read_lock();
+	ret = notifier_call_chain(&nh->head, val, v, -1, NULL);
+	rcu_read_unlock();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_call_chain);
+NOKPROBE_SYMBOL(atomic_notifier_call_chain);
+
+/**
+ *	atomic_notifier_call_chain_is_empty - Check whether notifier chain is empty
+ *	@nh: Pointer to head of the atomic notifier chain
+ *
+ *	Checks whether notifier chain is empty.
+ *
+ *	Returns true is notifier chain is empty, false otherwise.
+ */
+bool atomic_notifier_call_chain_is_empty(struct atomic_notifier_head *nh)
+{
+	return !rcu_access_pointer(nh->head);
+}
+
+/*
+ *	Blocking notifier chain routines.  All access to the chain is
+ *	synchronized by an rwsem.
+ */
+
+static int __blocking_notifier_chain_register(struct blocking_notifier_head *nh,
+					      struct notifier_block *n,
+					      bool unique_priority)
+{
+	int ret;
+
+	/*
+	 * This code gets used during boot-up, when task switching is
+	 * not yet working and interrupts must remain disabled.  At
+	 * such times we must not call down_write().
+	 */
+	if (unlikely(system_state == SYSTEM_BOOTING))
+		return notifier_chain_register(&nh->head, n, unique_priority);
+
+	down_write(&nh->rwsem);
+	ret = notifier_chain_register(&nh->head, n, unique_priority);
+	up_write(&nh->rwsem);
+	return ret;
+}
+
+/**
+ *	blocking_notifier_chain_register - Add notifier to a blocking notifier chain
+ *	@nh: Pointer to head of the blocking notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to a blocking notifier chain.
+ *	Must be called in process context.
+ *
+ *	Returns 0 on success, %-EEXIST on error.
+ */
+int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
+		struct notifier_block *n)
+{
+	return __blocking_notifier_chain_register(nh, n, false);
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_chain_register);
+
+/**
+ *	blocking_notifier_chain_register_unique_prio - Add notifier to a blocking notifier chain
+ *	@nh: Pointer to head of the blocking notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to an blocking notifier chain if there is no other
+ *	notifier registered using the same priority.
+ *
+ *	Returns 0 on success, %-EEXIST or %-EBUSY on error.
+ */
+int blocking_notifier_chain_register_unique_prio(struct blocking_notifier_head *nh,
+						 struct notifier_block *n)
+{
+	return __blocking_notifier_chain_register(nh, n, true);
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_chain_register_unique_prio);
+
+/**
+ *	blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain
+ *	@nh: Pointer to head of the blocking notifier chain
+ *	@n: Entry to remove from notifier chain
+ *
+ *	Removes a notifier from a blocking notifier chain.
+ *	Must be called from process context.
+ *
+ *	Returns zero on success or %-ENOENT on failure.
+ */
+int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
+		struct notifier_block *n)
+{
+	int ret;
+
+	/*
+	 * This code gets used during boot-up, when task switching is
+	 * not yet working and interrupts must remain disabled.  At
+	 * such times we must not call down_write().
+	 */
+	if (unlikely(system_state == SYSTEM_BOOTING))
+		return notifier_chain_unregister(&nh->head, n);
+
+	down_write(&nh->rwsem);
+	ret = notifier_chain_unregister(&nh->head, n);
+	up_write(&nh->rwsem);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_chain_unregister);
+
+int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh,
+		unsigned long val_up, unsigned long val_down, void *v)
+{
+	int ret = NOTIFY_DONE;
+
+	/*
+	 * We check the head outside the lock, but if this access is
+	 * racy then it does not matter what the result of the test
+	 * is, we re-check the list after having taken the lock anyway:
+	 */
+	if (rcu_access_pointer(nh->head)) {
+		down_read(&nh->rwsem);
+		ret = notifier_call_chain_robust(&nh->head, val_up, val_down, v);
+		up_read(&nh->rwsem);
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_call_chain_robust);
+
+/**
+ *	blocking_notifier_call_chain - Call functions in a blocking notifier chain
+ *	@nh: Pointer to head of the blocking notifier chain
+ *	@val: Value passed unmodified to notifier function
+ *	@v: Pointer passed unmodified to notifier function
+ *
+ *	Calls each function in a notifier chain in turn.  The functions
+ *	run in a process context, so they are allowed to block.
+ *
+ *	If the return value of the notifier can be and'ed
+ *	with %NOTIFY_STOP_MASK then blocking_notifier_call_chain()
+ *	will return immediately, with the return value of
+ *	the notifier function which halted execution.
+ *	Otherwise the return value is the return value
+ *	of the last notifier function called.
+ */
+int blocking_notifier_call_chain(struct blocking_notifier_head *nh,
+		unsigned long val, void *v)
+{
+	int ret = NOTIFY_DONE;
+
+	/*
+	 * We check the head outside the lock, but if this access is
+	 * racy then it does not matter what the result of the test
+	 * is, we re-check the list after having taken the lock anyway:
+	 */
+	if (rcu_access_pointer(nh->head)) {
+		down_read(&nh->rwsem);
+		ret = notifier_call_chain(&nh->head, val, v, -1, NULL);
+		up_read(&nh->rwsem);
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
+
+/*
+ *	Raw notifier chain routines.  There is no protection;
+ *	the caller must provide it.  Use at your own risk!
+ */
+
+/**
+ *	raw_notifier_chain_register - Add notifier to a raw notifier chain
+ *	@nh: Pointer to head of the raw notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to a raw notifier chain.
+ *	All locking must be provided by the caller.
+ *
+ *	Returns 0 on success, %-EEXIST on error.
+ */
+int raw_notifier_chain_register(struct raw_notifier_head *nh,
+		struct notifier_block *n)
+{
+	return notifier_chain_register(&nh->head, n, false);
+}
+EXPORT_SYMBOL_GPL(raw_notifier_chain_register);
+
+/**
+ *	raw_notifier_chain_unregister - Remove notifier from a raw notifier chain
+ *	@nh: Pointer to head of the raw notifier chain
+ *	@n: Entry to remove from notifier chain
+ *
+ *	Removes a notifier from a raw notifier chain.
+ *	All locking must be provided by the caller.
+ *
+ *	Returns zero on success or %-ENOENT on failure.
+ */
+int raw_notifier_chain_unregister(struct raw_notifier_head *nh,
+		struct notifier_block *n)
+{
+	return notifier_chain_unregister(&nh->head, n);
+}
+EXPORT_SYMBOL_GPL(raw_notifier_chain_unregister);
+
+int raw_notifier_call_chain_robust(struct raw_notifier_head *nh,
+		unsigned long val_up, unsigned long val_down, void *v)
+{
+	return notifier_call_chain_robust(&nh->head, val_up, val_down, v);
+}
+EXPORT_SYMBOL_GPL(raw_notifier_call_chain_robust);
+
+/**
+ *	raw_notifier_call_chain - Call functions in a raw notifier chain
+ *	@nh: Pointer to head of the raw notifier chain
+ *	@val: Value passed unmodified to notifier function
+ *	@v: Pointer passed unmodified to notifier function
+ *
+ *	Calls each function in a notifier chain in turn.  The functions
+ *	run in an undefined context.
+ *	All locking must be provided by the caller.
+ *
+ *	If the return value of the notifier can be and'ed
+ *	with %NOTIFY_STOP_MASK then raw_notifier_call_chain()
+ *	will return immediately, with the return value of
+ *	the notifier function which halted execution.
+ *	Otherwise the return value is the return value
+ *	of the last notifier function called.
+ */
+int raw_notifier_call_chain(struct raw_notifier_head *nh,
+		unsigned long val, void *v)
+{
+	return notifier_call_chain(&nh->head, val, v, -1, NULL);
+}
+EXPORT_SYMBOL_GPL(raw_notifier_call_chain);
+
+#ifdef CONFIG_SRCU
+/*
+ *	SRCU notifier chain routines.    Registration and unregistration
+ *	use a mutex, and call_chain is synchronized by SRCU (no locks).
+ */
+
+/**
+ *	srcu_notifier_chain_register - Add notifier to an SRCU notifier chain
+ *	@nh: Pointer to head of the SRCU notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to an SRCU notifier chain.
+ *	Must be called in process context.
+ *
+ *	Returns 0 on success, %-EEXIST on error.
+ */
+int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
+		struct notifier_block *n)
+{
+	int ret;
+
+	/*
+	 * This code gets used during boot-up, when task switching is
+	 * not yet working and interrupts must remain disabled.  At
+	 * such times we must not call mutex_lock().
+	 */
+	if (unlikely(system_state == SYSTEM_BOOTING))
+		return notifier_chain_register(&nh->head, n, false);
+
+	mutex_lock(&nh->mutex);
+	ret = notifier_chain_register(&nh->head, n, false);
+	mutex_unlock(&nh->mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(srcu_notifier_chain_register);
+
+/**
+ *	srcu_notifier_chain_unregister - Remove notifier from an SRCU notifier chain
+ *	@nh: Pointer to head of the SRCU notifier chain
+ *	@n: Entry to remove from notifier chain
+ *
+ *	Removes a notifier from an SRCU notifier chain.
+ *	Must be called from process context.
+ *
+ *	Returns zero on success or %-ENOENT on failure.
+ */
+int srcu_notifier_chain_unregister(struct srcu_notifier_head *nh,
+		struct notifier_block *n)
+{
+	int ret;
+
+	/*
+	 * This code gets used during boot-up, when task switching is
+	 * not yet working and interrupts must remain disabled.  At
+	 * such times we must not call mutex_lock().
+	 */
+	if (unlikely(system_state == SYSTEM_BOOTING))
+		return notifier_chain_unregister(&nh->head, n);
+
+	mutex_lock(&nh->mutex);
+	ret = notifier_chain_unregister(&nh->head, n);
+	mutex_unlock(&nh->mutex);
+	synchronize_srcu(&nh->srcu);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(srcu_notifier_chain_unregister);
+
+/**
+ *	srcu_notifier_call_chain - Call functions in an SRCU notifier chain
+ *	@nh: Pointer to head of the SRCU notifier chain
+ *	@val: Value passed unmodified to notifier function
+ *	@v: Pointer passed unmodified to notifier function
+ *
+ *	Calls each function in a notifier chain in turn.  The functions
+ *	run in a process context, so they are allowed to block.
+ *
+ *	If the return value of the notifier can be and'ed
+ *	with %NOTIFY_STOP_MASK then srcu_notifier_call_chain()
+ *	will return immediately, with the return value of
+ *	the notifier function which halted execution.
+ *	Otherwise the return value is the return value
+ *	of the last notifier function called.
+ */
+int srcu_notifier_call_chain(struct srcu_notifier_head *nh,
+		unsigned long val, void *v)
+{
+	int ret;
+	int idx;
+
+	idx = srcu_read_lock(&nh->srcu);
+	ret = notifier_call_chain(&nh->head, val, v, -1, NULL);
+	srcu_read_unlock(&nh->srcu, idx);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(srcu_notifier_call_chain);
+
+/**
+ *	srcu_init_notifier_head - Initialize an SRCU notifier head
+ *	@nh: Pointer to head of the srcu notifier chain
+ *
+ *	Unlike other sorts of notifier heads, SRCU notifier heads require
+ *	dynamic initialization.  Be sure to call this routine before
+ *	calling any of the other SRCU notifier routines for this head.
+ *
+ *	If an SRCU notifier head is deallocated, it must first be cleaned
+ *	up by calling srcu_cleanup_notifier_head().  Otherwise the head's
+ *	per-cpu data (used by the SRCU mechanism) will leak.
+ */
+void srcu_init_notifier_head(struct srcu_notifier_head *nh)
+{
+	mutex_init(&nh->mutex);
+	if (init_srcu_struct(&nh->srcu) < 0)
+		BUG();
+	nh->head = NULL;
+}
+EXPORT_SYMBOL_GPL(srcu_init_notifier_head);
+
+#endif /* CONFIG_SRCU */
+
+static ATOMIC_NOTIFIER_HEAD(die_chain);
+
+int notrace notify_die(enum die_val val, const char *str,
+	       struct pt_regs *regs, long err, int trap, int sig)
+{
+	struct die_args args = {
+		.regs	= regs,
+		.str	= str,
+		.err	= err,
+		.trapnr	= trap,
+		.signr	= sig,
+
+	};
+	RCU_LOCKDEP_WARN(!rcu_is_watching(),
+			   "notify_die called but RCU thinks we're quiescent");
+	return atomic_notifier_call_chain(&die_chain, val, &args);
+}
+NOKPROBE_SYMBOL(notify_die);
+
+int register_die_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_register(&die_chain, nb);
+}
+EXPORT_SYMBOL_GPL(register_die_notifier);
+
+int unregister_die_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_unregister(&die_chain, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_die_notifier);
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
new file mode 100644
index 000000000..eec72ca96
--- /dev/null
+++ b/kernel/nsproxy.c
@@ -0,0 +1,573 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Copyright (C) 2006 IBM Corporation
+ *
+ *  Author: Serge Hallyn <serue@us.ibm.com>
+ *
+ *  Jun 2006 - namespaces support
+ *             OpenVZ, SWsoft Inc.
+ *             Pavel Emelianov <xemul@openvz.org>
+ */
+
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/nsproxy.h>
+#include <linux/init_task.h>
+#include <linux/mnt_namespace.h>
+#include <linux/utsname.h>
+#include <linux/pid_namespace.h>
+#include <net/net_namespace.h>
+#include <linux/ipc_namespace.h>
+#include <linux/time_namespace.h>
+#include <linux/fs_struct.h>
+#include <linux/proc_fs.h>
+#include <linux/proc_ns.h>
+#include <linux/file.h>
+#include <linux/syscalls.h>
+#include <linux/cgroup.h>
+#include <linux/perf_event.h>
+
+static struct kmem_cache *nsproxy_cachep;
+
+struct nsproxy init_nsproxy = {
+	.count			= ATOMIC_INIT(1),
+	.uts_ns			= &init_uts_ns,
+#if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
+	.ipc_ns			= &init_ipc_ns,
+#endif
+	.mnt_ns			= NULL,
+	.pid_ns_for_children	= &init_pid_ns,
+#ifdef CONFIG_NET
+	.net_ns			= &init_net,
+#endif
+#ifdef CONFIG_CGROUPS
+	.cgroup_ns		= &init_cgroup_ns,
+#endif
+#ifdef CONFIG_TIME_NS
+	.time_ns		= &init_time_ns,
+	.time_ns_for_children	= &init_time_ns,
+#endif
+};
+
+static inline struct nsproxy *create_nsproxy(void)
+{
+	struct nsproxy *nsproxy;
+
+	nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
+	if (nsproxy)
+		atomic_set(&nsproxy->count, 1);
+	return nsproxy;
+}
+
+/*
+ * Create new nsproxy and all of its the associated namespaces.
+ * Return the newly created nsproxy.  Do not attach this to the task,
+ * leave it to the caller to do proper locking and attach it to task.
+ */
+static struct nsproxy *create_new_namespaces(unsigned long flags,
+	struct task_struct *tsk, struct user_namespace *user_ns,
+	struct fs_struct *new_fs)
+{
+	struct nsproxy *new_nsp;
+	int err;
+
+	new_nsp = create_nsproxy();
+	if (!new_nsp)
+		return ERR_PTR(-ENOMEM);
+
+	new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
+	if (IS_ERR(new_nsp->mnt_ns)) {
+		err = PTR_ERR(new_nsp->mnt_ns);
+		goto out_ns;
+	}
+
+	new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns);
+	if (IS_ERR(new_nsp->uts_ns)) {
+		err = PTR_ERR(new_nsp->uts_ns);
+		goto out_uts;
+	}
+
+	new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns);
+	if (IS_ERR(new_nsp->ipc_ns)) {
+		err = PTR_ERR(new_nsp->ipc_ns);
+		goto out_ipc;
+	}
+
+	new_nsp->pid_ns_for_children =
+		copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children);
+	if (IS_ERR(new_nsp->pid_ns_for_children)) {
+		err = PTR_ERR(new_nsp->pid_ns_for_children);
+		goto out_pid;
+	}
+
+	new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
+					    tsk->nsproxy->cgroup_ns);
+	if (IS_ERR(new_nsp->cgroup_ns)) {
+		err = PTR_ERR(new_nsp->cgroup_ns);
+		goto out_cgroup;
+	}
+
+	new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
+	if (IS_ERR(new_nsp->net_ns)) {
+		err = PTR_ERR(new_nsp->net_ns);
+		goto out_net;
+	}
+
+	new_nsp->time_ns_for_children = copy_time_ns(flags, user_ns,
+					tsk->nsproxy->time_ns_for_children);
+	if (IS_ERR(new_nsp->time_ns_for_children)) {
+		err = PTR_ERR(new_nsp->time_ns_for_children);
+		goto out_time;
+	}
+	new_nsp->time_ns = get_time_ns(tsk->nsproxy->time_ns);
+
+	return new_nsp;
+
+out_time:
+	put_net(new_nsp->net_ns);
+out_net:
+	put_cgroup_ns(new_nsp->cgroup_ns);
+out_cgroup:
+	if (new_nsp->pid_ns_for_children)
+		put_pid_ns(new_nsp->pid_ns_for_children);
+out_pid:
+	if (new_nsp->ipc_ns)
+		put_ipc_ns(new_nsp->ipc_ns);
+out_ipc:
+	if (new_nsp->uts_ns)
+		put_uts_ns(new_nsp->uts_ns);
+out_uts:
+	if (new_nsp->mnt_ns)
+		put_mnt_ns(new_nsp->mnt_ns);
+out_ns:
+	kmem_cache_free(nsproxy_cachep, new_nsp);
+	return ERR_PTR(err);
+}
+
+/*
+ * called from clone.  This now handles copy for nsproxy and all
+ * namespaces therein.
+ */
+int copy_namespaces(unsigned long flags, struct task_struct *tsk)
+{
+	struct nsproxy *old_ns = tsk->nsproxy;
+	struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
+	struct nsproxy *new_ns;
+
+	if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+			      CLONE_NEWPID | CLONE_NEWNET |
+			      CLONE_NEWCGROUP | CLONE_NEWTIME)))) {
+		if (likely(old_ns->time_ns_for_children == old_ns->time_ns)) {
+			get_nsproxy(old_ns);
+			return 0;
+		}
+	} else if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	/*
+	 * CLONE_NEWIPC must detach from the undolist: after switching
+	 * to a new ipc namespace, the semaphore arrays from the old
+	 * namespace are unreachable.  In clone parlance, CLONE_SYSVSEM
+	 * means share undolist with parent, so we must forbid using
+	 * it along with CLONE_NEWIPC.
+	 */
+	if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) ==
+		(CLONE_NEWIPC | CLONE_SYSVSEM))
+		return -EINVAL;
+
+	new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
+	if (IS_ERR(new_ns))
+		return  PTR_ERR(new_ns);
+
+	timens_on_fork(new_ns, tsk);
+
+	tsk->nsproxy = new_ns;
+	return 0;
+}
+
+void free_nsproxy(struct nsproxy *ns)
+{
+	if (ns->mnt_ns)
+		put_mnt_ns(ns->mnt_ns);
+	if (ns->uts_ns)
+		put_uts_ns(ns->uts_ns);
+	if (ns->ipc_ns)
+		put_ipc_ns(ns->ipc_ns);
+	if (ns->pid_ns_for_children)
+		put_pid_ns(ns->pid_ns_for_children);
+	if (ns->time_ns)
+		put_time_ns(ns->time_ns);
+	if (ns->time_ns_for_children)
+		put_time_ns(ns->time_ns_for_children);
+	put_cgroup_ns(ns->cgroup_ns);
+	put_net(ns->net_ns);
+	kmem_cache_free(nsproxy_cachep, ns);
+}
+
+/*
+ * Called from unshare. Unshare all the namespaces part of nsproxy.
+ * On success, returns the new nsproxy.
+ */
+int unshare_nsproxy_namespaces(unsigned long unshare_flags,
+	struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs)
+{
+	struct user_namespace *user_ns;
+	int err = 0;
+
+	if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+			       CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP |
+			       CLONE_NEWTIME)))
+		return 0;
+
+	user_ns = new_cred ? new_cred->user_ns : current_user_ns();
+	if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	*new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
+					 new_fs ? new_fs : current->fs);
+	if (IS_ERR(*new_nsp)) {
+		err = PTR_ERR(*new_nsp);
+		goto out;
+	}
+
+out:
+	return err;
+}
+
+void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
+{
+	struct nsproxy *ns;
+
+	might_sleep();
+
+	task_lock(p);
+	ns = p->nsproxy;
+	p->nsproxy = new;
+	task_unlock(p);
+
+	if (ns)
+		put_nsproxy(ns);
+}
+
+void exit_task_namespaces(struct task_struct *p)
+{
+	switch_task_namespaces(p, NULL);
+}
+
+static int check_setns_flags(unsigned long flags)
+{
+	if (!flags || (flags & ~(CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
+				 CLONE_NEWNET | CLONE_NEWTIME | CLONE_NEWUSER |
+				 CLONE_NEWPID | CLONE_NEWCGROUP)))
+		return -EINVAL;
+
+#ifndef CONFIG_USER_NS
+	if (flags & CLONE_NEWUSER)
+		return -EINVAL;
+#endif
+#ifndef CONFIG_PID_NS
+	if (flags & CLONE_NEWPID)
+		return -EINVAL;
+#endif
+#ifndef CONFIG_UTS_NS
+	if (flags & CLONE_NEWUTS)
+		return -EINVAL;
+#endif
+#ifndef CONFIG_IPC_NS
+	if (flags & CLONE_NEWIPC)
+		return -EINVAL;
+#endif
+#ifndef CONFIG_CGROUPS
+	if (flags & CLONE_NEWCGROUP)
+		return -EINVAL;
+#endif
+#ifndef CONFIG_NET_NS
+	if (flags & CLONE_NEWNET)
+		return -EINVAL;
+#endif
+#ifndef CONFIG_TIME_NS
+	if (flags & CLONE_NEWTIME)
+		return -EINVAL;
+#endif
+
+	return 0;
+}
+
+static void put_nsset(struct nsset *nsset)
+{
+	unsigned flags = nsset->flags;
+
+	if (flags & CLONE_NEWUSER)
+		put_cred(nsset_cred(nsset));
+	/*
+	 * We only created a temporary copy if we attached to more than just
+	 * the mount namespace.
+	 */
+	if (nsset->fs && (flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS))
+		free_fs_struct(nsset->fs);
+	if (nsset->nsproxy)
+		free_nsproxy(nsset->nsproxy);
+}
+
+static int prepare_nsset(unsigned flags, struct nsset *nsset)
+{
+	struct task_struct *me = current;
+
+	nsset->nsproxy = create_new_namespaces(0, me, current_user_ns(), me->fs);
+	if (IS_ERR(nsset->nsproxy))
+		return PTR_ERR(nsset->nsproxy);
+
+	if (flags & CLONE_NEWUSER)
+		nsset->cred = prepare_creds();
+	else
+		nsset->cred = current_cred();
+	if (!nsset->cred)
+		goto out;
+
+	/* Only create a temporary copy of fs_struct if we really need to. */
+	if (flags == CLONE_NEWNS) {
+		nsset->fs = me->fs;
+	} else if (flags & CLONE_NEWNS) {
+		nsset->fs = copy_fs_struct(me->fs);
+		if (!nsset->fs)
+			goto out;
+	}
+
+	nsset->flags = flags;
+	return 0;
+
+out:
+	put_nsset(nsset);
+	return -ENOMEM;
+}
+
+static inline int validate_ns(struct nsset *nsset, struct ns_common *ns)
+{
+	return ns->ops->install(nsset, ns);
+}
+
+/*
+ * This is the inverse operation to unshare().
+ * Ordering is equivalent to the standard ordering used everywhere else
+ * during unshare and process creation. The switch to the new set of
+ * namespaces occurs at the point of no return after installation of
+ * all requested namespaces was successful in commit_nsset().
+ */
+static int validate_nsset(struct nsset *nsset, struct pid *pid)
+{
+	int ret = 0;
+	unsigned flags = nsset->flags;
+	struct user_namespace *user_ns = NULL;
+	struct pid_namespace *pid_ns = NULL;
+	struct nsproxy *nsp;
+	struct task_struct *tsk;
+
+	/* Take a "snapshot" of the target task's namespaces. */
+	rcu_read_lock();
+	tsk = pid_task(pid, PIDTYPE_PID);
+	if (!tsk) {
+		rcu_read_unlock();
+		return -ESRCH;
+	}
+
+	if (!ptrace_may_access(tsk, PTRACE_MODE_READ_REALCREDS)) {
+		rcu_read_unlock();
+		return -EPERM;
+	}
+
+	task_lock(tsk);
+	nsp = tsk->nsproxy;
+	if (nsp)
+		get_nsproxy(nsp);
+	task_unlock(tsk);
+	if (!nsp) {
+		rcu_read_unlock();
+		return -ESRCH;
+	}
+
+#ifdef CONFIG_PID_NS
+	if (flags & CLONE_NEWPID) {
+		pid_ns = task_active_pid_ns(tsk);
+		if (unlikely(!pid_ns)) {
+			rcu_read_unlock();
+			ret = -ESRCH;
+			goto out;
+		}
+		get_pid_ns(pid_ns);
+	}
+#endif
+
+#ifdef CONFIG_USER_NS
+	if (flags & CLONE_NEWUSER)
+		user_ns = get_user_ns(__task_cred(tsk)->user_ns);
+#endif
+	rcu_read_unlock();
+
+	/*
+	 * Install requested namespaces. The caller will have
+	 * verified earlier that the requested namespaces are
+	 * supported on this kernel. We don't report errors here
+	 * if a namespace is requested that isn't supported.
+	 */
+#ifdef CONFIG_USER_NS
+	if (flags & CLONE_NEWUSER) {
+		ret = validate_ns(nsset, &user_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+	if (flags & CLONE_NEWNS) {
+		ret = validate_ns(nsset, from_mnt_ns(nsp->mnt_ns));
+		if (ret)
+			goto out;
+	}
+
+#ifdef CONFIG_UTS_NS
+	if (flags & CLONE_NEWUTS) {
+		ret = validate_ns(nsset, &nsp->uts_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+#ifdef CONFIG_IPC_NS
+	if (flags & CLONE_NEWIPC) {
+		ret = validate_ns(nsset, &nsp->ipc_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+#ifdef CONFIG_PID_NS
+	if (flags & CLONE_NEWPID) {
+		ret = validate_ns(nsset, &pid_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+#ifdef CONFIG_CGROUPS
+	if (flags & CLONE_NEWCGROUP) {
+		ret = validate_ns(nsset, &nsp->cgroup_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+#ifdef CONFIG_NET_NS
+	if (flags & CLONE_NEWNET) {
+		ret = validate_ns(nsset, &nsp->net_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+#ifdef CONFIG_TIME_NS
+	if (flags & CLONE_NEWTIME) {
+		ret = validate_ns(nsset, &nsp->time_ns->ns);
+		if (ret)
+			goto out;
+	}
+#endif
+
+out:
+	if (pid_ns)
+		put_pid_ns(pid_ns);
+	if (nsp)
+		put_nsproxy(nsp);
+	put_user_ns(user_ns);
+
+	return ret;
+}
+
+/*
+ * This is the point of no return. There are just a few namespaces
+ * that do some actual work here and it's sufficiently minimal that
+ * a separate ns_common operation seems unnecessary for now.
+ * Unshare is doing the same thing. If we'll end up needing to do
+ * more in a given namespace or a helper here is ultimately not
+ * exported anymore a simple commit handler for each namespace
+ * should be added to ns_common.
+ */
+static void commit_nsset(struct nsset *nsset)
+{
+	unsigned flags = nsset->flags;
+	struct task_struct *me = current;
+
+#ifdef CONFIG_USER_NS
+	if (flags & CLONE_NEWUSER) {
+		/* transfer ownership */
+		commit_creds(nsset_cred(nsset));
+		nsset->cred = NULL;
+	}
+#endif
+
+	/* We only need to commit if we have used a temporary fs_struct. */
+	if ((flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS)) {
+		set_fs_root(me->fs, &nsset->fs->root);
+		set_fs_pwd(me->fs, &nsset->fs->pwd);
+	}
+
+#ifdef CONFIG_IPC_NS
+	if (flags & CLONE_NEWIPC)
+		exit_sem(me);
+#endif
+
+#ifdef CONFIG_TIME_NS
+	if (flags & CLONE_NEWTIME)
+		timens_commit(me, nsset->nsproxy->time_ns);
+#endif
+
+	/* transfer ownership */
+	switch_task_namespaces(me, nsset->nsproxy);
+	nsset->nsproxy = NULL;
+}
+
+SYSCALL_DEFINE2(setns, int, fd, int, flags)
+{
+	struct file *file;
+	struct ns_common *ns = NULL;
+	struct nsset nsset = {};
+	int err = 0;
+
+	file = fget(fd);
+	if (!file)
+		return -EBADF;
+
+	if (proc_ns_file(file)) {
+		ns = get_proc_ns(file_inode(file));
+		if (flags && (ns->ops->type != flags))
+			err = -EINVAL;
+		flags = ns->ops->type;
+	} else if (!IS_ERR(pidfd_pid(file))) {
+		err = check_setns_flags(flags);
+	} else {
+		err = -EINVAL;
+	}
+	if (err)
+		goto out;
+
+	err = prepare_nsset(flags, &nsset);
+	if (err)
+		goto out;
+
+	if (proc_ns_file(file))
+		err = validate_ns(&nsset, ns);
+	else
+		err = validate_nsset(&nsset, file->private_data);
+	if (!err) {
+		commit_nsset(&nsset);
+		perf_event_namespaces(current);
+	}
+	put_nsset(&nsset);
+out:
+	fput(file);
+	return err;
+}
+
+int __init nsproxy_cache_init(void)
+{
+	nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC|SLAB_ACCOUNT);
+	return 0;
+}
diff --git a/kernel/padata.c b/kernel/padata.c
new file mode 100644
index 000000000..7bef7dae3
--- /dev/null
+++ b/kernel/padata.c
@@ -0,0 +1,1150 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * padata.c - generic interface to process data streams in parallel
+ *
+ * See Documentation/core-api/padata.rst for more information.
+ *
+ * Copyright (C) 2008, 2009 secunet Security Networks AG
+ * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
+ *
+ * Copyright (c) 2020 Oracle and/or its affiliates.
+ * Author: Daniel Jordan <daniel.m.jordan@oracle.com>
+ */
+
+#include <linux/completion.h>
+#include <linux/export.h>
+#include <linux/cpumask.h>
+#include <linux/err.h>
+#include <linux/cpu.h>
+#include <linux/padata.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/rcupdate.h>
+
+#define	PADATA_WORK_ONSTACK	1	/* Work's memory is on stack */
+
+struct padata_work {
+	struct work_struct	pw_work;
+	struct list_head	pw_list;  /* padata_free_works linkage */
+	void			*pw_data;
+};
+
+static DEFINE_SPINLOCK(padata_works_lock);
+static struct padata_work *padata_works;
+static LIST_HEAD(padata_free_works);
+
+struct padata_mt_job_state {
+	spinlock_t		lock;
+	struct completion	completion;
+	struct padata_mt_job	*job;
+	int			nworks;
+	int			nworks_fini;
+	unsigned long		chunk_size;
+};
+
+static void padata_free_pd(struct parallel_data *pd);
+static void __init padata_mt_helper(struct work_struct *work);
+
+static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
+{
+	int cpu, target_cpu;
+
+	target_cpu = cpumask_first(pd->cpumask.pcpu);
+	for (cpu = 0; cpu < cpu_index; cpu++)
+		target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
+
+	return target_cpu;
+}
+
+static int padata_cpu_hash(struct parallel_data *pd, unsigned int seq_nr)
+{
+	/*
+	 * Hash the sequence numbers to the cpus by taking
+	 * seq_nr mod. number of cpus in use.
+	 */
+	int cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
+
+	return padata_index_to_cpu(pd, cpu_index);
+}
+
+static struct padata_work *padata_work_alloc(void)
+{
+	struct padata_work *pw;
+
+	lockdep_assert_held(&padata_works_lock);
+
+	if (list_empty(&padata_free_works))
+		return NULL;	/* No more work items allowed to be queued. */
+
+	pw = list_first_entry(&padata_free_works, struct padata_work, pw_list);
+	list_del(&pw->pw_list);
+	return pw;
+}
+
+static void padata_work_init(struct padata_work *pw, work_func_t work_fn,
+			     void *data, int flags)
+{
+	if (flags & PADATA_WORK_ONSTACK)
+		INIT_WORK_ONSTACK(&pw->pw_work, work_fn);
+	else
+		INIT_WORK(&pw->pw_work, work_fn);
+	pw->pw_data = data;
+}
+
+static int __init padata_work_alloc_mt(int nworks, void *data,
+				       struct list_head *head)
+{
+	int i;
+
+	spin_lock(&padata_works_lock);
+	/* Start at 1 because the current task participates in the job. */
+	for (i = 1; i < nworks; ++i) {
+		struct padata_work *pw = padata_work_alloc();
+
+		if (!pw)
+			break;
+		padata_work_init(pw, padata_mt_helper, data, 0);
+		list_add(&pw->pw_list, head);
+	}
+	spin_unlock(&padata_works_lock);
+
+	return i;
+}
+
+static void padata_work_free(struct padata_work *pw)
+{
+	lockdep_assert_held(&padata_works_lock);
+	list_add(&pw->pw_list, &padata_free_works);
+}
+
+static void __init padata_works_free(struct list_head *works)
+{
+	struct padata_work *cur, *next;
+
+	if (list_empty(works))
+		return;
+
+	spin_lock(&padata_works_lock);
+	list_for_each_entry_safe(cur, next, works, pw_list) {
+		list_del(&cur->pw_list);
+		padata_work_free(cur);
+	}
+	spin_unlock(&padata_works_lock);
+}
+
+static void padata_parallel_worker(struct work_struct *parallel_work)
+{
+	struct padata_work *pw = container_of(parallel_work, struct padata_work,
+					      pw_work);
+	struct padata_priv *padata = pw->pw_data;
+
+	local_bh_disable();
+	padata->parallel(padata);
+	spin_lock(&padata_works_lock);
+	padata_work_free(pw);
+	spin_unlock(&padata_works_lock);
+	local_bh_enable();
+}
+
+/**
+ * padata_do_parallel - padata parallelization function
+ *
+ * @ps: padatashell
+ * @padata: object to be parallelized
+ * @cb_cpu: pointer to the CPU that the serialization callback function should
+ *          run on.  If it's not in the serial cpumask of @pinst
+ *          (i.e. cpumask.cbcpu), this function selects a fallback CPU and if
+ *          none found, returns -EINVAL.
+ *
+ * The parallelization callback function will run with BHs off.
+ * Note: Every object which is parallelized by padata_do_parallel
+ * must be seen by padata_do_serial.
+ *
+ * Return: 0 on success or else negative error code.
+ */
+int padata_do_parallel(struct padata_shell *ps,
+		       struct padata_priv *padata, int *cb_cpu)
+{
+	struct padata_instance *pinst = ps->pinst;
+	int i, cpu, cpu_index, err;
+	struct parallel_data *pd;
+	struct padata_work *pw;
+
+	rcu_read_lock_bh();
+
+	pd = rcu_dereference_bh(ps->pd);
+
+	err = -EINVAL;
+	if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
+		goto out;
+
+	if (!cpumask_test_cpu(*cb_cpu, pd->cpumask.cbcpu)) {
+		if (cpumask_empty(pd->cpumask.cbcpu))
+			goto out;
+
+		/* Select an alternate fallback CPU and notify the caller. */
+		cpu_index = *cb_cpu % cpumask_weight(pd->cpumask.cbcpu);
+
+		cpu = cpumask_first(pd->cpumask.cbcpu);
+		for (i = 0; i < cpu_index; i++)
+			cpu = cpumask_next(cpu, pd->cpumask.cbcpu);
+
+		*cb_cpu = cpu;
+	}
+
+	err = -EBUSY;
+	if ((pinst->flags & PADATA_RESET))
+		goto out;
+
+	refcount_inc(&pd->refcnt);
+	padata->pd = pd;
+	padata->cb_cpu = *cb_cpu;
+
+	spin_lock(&padata_works_lock);
+	padata->seq_nr = ++pd->seq_nr;
+	pw = padata_work_alloc();
+	spin_unlock(&padata_works_lock);
+
+	if (!pw) {
+		/* Maximum works limit exceeded, run in the current task. */
+		padata->parallel(padata);
+	}
+
+	rcu_read_unlock_bh();
+
+	if (pw) {
+		padata_work_init(pw, padata_parallel_worker, padata, 0);
+		queue_work(pinst->parallel_wq, &pw->pw_work);
+	}
+
+	return 0;
+out:
+	rcu_read_unlock_bh();
+
+	return err;
+}
+EXPORT_SYMBOL(padata_do_parallel);
+
+/*
+ * padata_find_next - Find the next object that needs serialization.
+ *
+ * Return:
+ * * A pointer to the control struct of the next object that needs
+ *   serialization, if present in one of the percpu reorder queues.
+ * * NULL, if the next object that needs serialization will
+ *   be parallel processed by another cpu and is not yet present in
+ *   the cpu's reorder queue.
+ */
+static struct padata_priv *padata_find_next(struct parallel_data *pd,
+					    bool remove_object)
+{
+	struct padata_priv *padata;
+	struct padata_list *reorder;
+	int cpu = pd->cpu;
+
+	reorder = per_cpu_ptr(pd->reorder_list, cpu);
+
+	spin_lock(&reorder->lock);
+	if (list_empty(&reorder->list)) {
+		spin_unlock(&reorder->lock);
+		return NULL;
+	}
+
+	padata = list_entry(reorder->list.next, struct padata_priv, list);
+
+	/*
+	 * Checks the rare case where two or more parallel jobs have hashed to
+	 * the same CPU and one of the later ones finishes first.
+	 */
+	if (padata->seq_nr != pd->processed) {
+		spin_unlock(&reorder->lock);
+		return NULL;
+	}
+
+	if (remove_object) {
+		list_del_init(&padata->list);
+		++pd->processed;
+		pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1, false);
+	}
+
+	spin_unlock(&reorder->lock);
+	return padata;
+}
+
+static void padata_reorder(struct parallel_data *pd)
+{
+	struct padata_instance *pinst = pd->ps->pinst;
+	int cb_cpu;
+	struct padata_priv *padata;
+	struct padata_serial_queue *squeue;
+	struct padata_list *reorder;
+
+	/*
+	 * We need to ensure that only one cpu can work on dequeueing of
+	 * the reorder queue the time. Calculating in which percpu reorder
+	 * queue the next object will arrive takes some time. A spinlock
+	 * would be highly contended. Also it is not clear in which order
+	 * the objects arrive to the reorder queues. So a cpu could wait to
+	 * get the lock just to notice that there is nothing to do at the
+	 * moment. Therefore we use a trylock and let the holder of the lock
+	 * care for all the objects enqueued during the holdtime of the lock.
+	 */
+	if (!spin_trylock_bh(&pd->lock))
+		return;
+
+	while (1) {
+		padata = padata_find_next(pd, true);
+
+		/*
+		 * If the next object that needs serialization is parallel
+		 * processed by another cpu and is still on it's way to the
+		 * cpu's reorder queue, nothing to do for now.
+		 */
+		if (!padata)
+			break;
+
+		cb_cpu = padata->cb_cpu;
+		squeue = per_cpu_ptr(pd->squeue, cb_cpu);
+
+		spin_lock(&squeue->serial.lock);
+		list_add_tail(&padata->list, &squeue->serial.list);
+		spin_unlock(&squeue->serial.lock);
+
+		queue_work_on(cb_cpu, pinst->serial_wq, &squeue->work);
+	}
+
+	spin_unlock_bh(&pd->lock);
+
+	/*
+	 * The next object that needs serialization might have arrived to
+	 * the reorder queues in the meantime.
+	 *
+	 * Ensure reorder queue is read after pd->lock is dropped so we see
+	 * new objects from another task in padata_do_serial.  Pairs with
+	 * smp_mb in padata_do_serial.
+	 */
+	smp_mb();
+
+	reorder = per_cpu_ptr(pd->reorder_list, pd->cpu);
+	if (!list_empty(&reorder->list) && padata_find_next(pd, false))
+		queue_work(pinst->serial_wq, &pd->reorder_work);
+}
+
+static void invoke_padata_reorder(struct work_struct *work)
+{
+	struct parallel_data *pd;
+
+	local_bh_disable();
+	pd = container_of(work, struct parallel_data, reorder_work);
+	padata_reorder(pd);
+	local_bh_enable();
+}
+
+static void padata_serial_worker(struct work_struct *serial_work)
+{
+	struct padata_serial_queue *squeue;
+	struct parallel_data *pd;
+	LIST_HEAD(local_list);
+	int cnt;
+
+	local_bh_disable();
+	squeue = container_of(serial_work, struct padata_serial_queue, work);
+	pd = squeue->pd;
+
+	spin_lock(&squeue->serial.lock);
+	list_replace_init(&squeue->serial.list, &local_list);
+	spin_unlock(&squeue->serial.lock);
+
+	cnt = 0;
+
+	while (!list_empty(&local_list)) {
+		struct padata_priv *padata;
+
+		padata = list_entry(local_list.next,
+				    struct padata_priv, list);
+
+		list_del_init(&padata->list);
+
+		padata->serial(padata);
+		cnt++;
+	}
+	local_bh_enable();
+
+	if (refcount_sub_and_test(cnt, &pd->refcnt))
+		padata_free_pd(pd);
+}
+
+/**
+ * padata_do_serial - padata serialization function
+ *
+ * @padata: object to be serialized.
+ *
+ * padata_do_serial must be called for every parallelized object.
+ * The serialization callback function will run with BHs off.
+ */
+void padata_do_serial(struct padata_priv *padata)
+{
+	struct parallel_data *pd = padata->pd;
+	int hashed_cpu = padata_cpu_hash(pd, padata->seq_nr);
+	struct padata_list *reorder = per_cpu_ptr(pd->reorder_list, hashed_cpu);
+	struct padata_priv *cur;
+	struct list_head *pos;
+
+	spin_lock(&reorder->lock);
+	/* Sort in ascending order of sequence number. */
+	list_for_each_prev(pos, &reorder->list) {
+		cur = list_entry(pos, struct padata_priv, list);
+		if (cur->seq_nr < padata->seq_nr)
+			break;
+	}
+	list_add(&padata->list, pos);
+	spin_unlock(&reorder->lock);
+
+	/*
+	 * Ensure the addition to the reorder list is ordered correctly
+	 * with the trylock of pd->lock in padata_reorder.  Pairs with smp_mb
+	 * in padata_reorder.
+	 */
+	smp_mb();
+
+	padata_reorder(pd);
+}
+EXPORT_SYMBOL(padata_do_serial);
+
+static int padata_setup_cpumasks(struct padata_instance *pinst)
+{
+	struct workqueue_attrs *attrs;
+	int err;
+
+	attrs = alloc_workqueue_attrs();
+	if (!attrs)
+		return -ENOMEM;
+
+	/* Restrict parallel_wq workers to pd->cpumask.pcpu. */
+	cpumask_copy(attrs->cpumask, pinst->cpumask.pcpu);
+	err = apply_workqueue_attrs(pinst->parallel_wq, attrs);
+	free_workqueue_attrs(attrs);
+
+	return err;
+}
+
+static void __init padata_mt_helper(struct work_struct *w)
+{
+	struct padata_work *pw = container_of(w, struct padata_work, pw_work);
+	struct padata_mt_job_state *ps = pw->pw_data;
+	struct padata_mt_job *job = ps->job;
+	bool done;
+
+	spin_lock(&ps->lock);
+
+	while (job->size > 0) {
+		unsigned long start, size, end;
+
+		start = job->start;
+		/* So end is chunk size aligned if enough work remains. */
+		size = roundup(start + 1, ps->chunk_size) - start;
+		size = min(size, job->size);
+		end = start + size;
+
+		job->start = end;
+		job->size -= size;
+
+		spin_unlock(&ps->lock);
+		job->thread_fn(start, end, job->fn_arg);
+		spin_lock(&ps->lock);
+	}
+
+	++ps->nworks_fini;
+	done = (ps->nworks_fini == ps->nworks);
+	spin_unlock(&ps->lock);
+
+	if (done)
+		complete(&ps->completion);
+}
+
+/**
+ * padata_do_multithreaded - run a multithreaded job
+ * @job: Description of the job.
+ *
+ * See the definition of struct padata_mt_job for more details.
+ */
+void __init padata_do_multithreaded(struct padata_mt_job *job)
+{
+	/* In case threads finish at different times. */
+	static const unsigned long load_balance_factor = 4;
+	struct padata_work my_work, *pw;
+	struct padata_mt_job_state ps;
+	LIST_HEAD(works);
+	int nworks;
+
+	if (job->size == 0)
+		return;
+
+	/* Ensure at least one thread when size < min_chunk. */
+	nworks = max(job->size / job->min_chunk, 1ul);
+	nworks = min(nworks, job->max_threads);
+
+	if (nworks == 1) {
+		/* Single thread, no coordination needed, cut to the chase. */
+		job->thread_fn(job->start, job->start + job->size, job->fn_arg);
+		return;
+	}
+
+	spin_lock_init(&ps.lock);
+	init_completion(&ps.completion);
+	ps.job	       = job;
+	ps.nworks      = padata_work_alloc_mt(nworks, &ps, &works);
+	ps.nworks_fini = 0;
+
+	/*
+	 * Chunk size is the amount of work a helper does per call to the
+	 * thread function.  Load balance large jobs between threads by
+	 * increasing the number of chunks, guarantee at least the minimum
+	 * chunk size from the caller, and honor the caller's alignment.
+	 */
+	ps.chunk_size = job->size / (ps.nworks * load_balance_factor);
+	ps.chunk_size = max(ps.chunk_size, job->min_chunk);
+	ps.chunk_size = roundup(ps.chunk_size, job->align);
+
+	list_for_each_entry(pw, &works, pw_list)
+		queue_work(system_unbound_wq, &pw->pw_work);
+
+	/* Use the current thread, which saves starting a workqueue worker. */
+	padata_work_init(&my_work, padata_mt_helper, &ps, PADATA_WORK_ONSTACK);
+	padata_mt_helper(&my_work.pw_work);
+
+	/* Wait for all the helpers to finish. */
+	wait_for_completion(&ps.completion);
+
+	destroy_work_on_stack(&my_work.pw_work);
+	padata_works_free(&works);
+}
+
+static void __padata_list_init(struct padata_list *pd_list)
+{
+	INIT_LIST_HEAD(&pd_list->list);
+	spin_lock_init(&pd_list->lock);
+}
+
+/* Initialize all percpu queues used by serial workers */
+static void padata_init_squeues(struct parallel_data *pd)
+{
+	int cpu;
+	struct padata_serial_queue *squeue;
+
+	for_each_cpu(cpu, pd->cpumask.cbcpu) {
+		squeue = per_cpu_ptr(pd->squeue, cpu);
+		squeue->pd = pd;
+		__padata_list_init(&squeue->serial);
+		INIT_WORK(&squeue->work, padata_serial_worker);
+	}
+}
+
+/* Initialize per-CPU reorder lists */
+static void padata_init_reorder_list(struct parallel_data *pd)
+{
+	int cpu;
+	struct padata_list *list;
+
+	for_each_cpu(cpu, pd->cpumask.pcpu) {
+		list = per_cpu_ptr(pd->reorder_list, cpu);
+		__padata_list_init(list);
+	}
+}
+
+/* Allocate and initialize the internal cpumask dependend resources. */
+static struct parallel_data *padata_alloc_pd(struct padata_shell *ps)
+{
+	struct padata_instance *pinst = ps->pinst;
+	struct parallel_data *pd;
+
+	pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
+	if (!pd)
+		goto err;
+
+	pd->reorder_list = alloc_percpu(struct padata_list);
+	if (!pd->reorder_list)
+		goto err_free_pd;
+
+	pd->squeue = alloc_percpu(struct padata_serial_queue);
+	if (!pd->squeue)
+		goto err_free_reorder_list;
+
+	pd->ps = ps;
+
+	if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
+		goto err_free_squeue;
+	if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL))
+		goto err_free_pcpu;
+
+	cpumask_and(pd->cpumask.pcpu, pinst->cpumask.pcpu, cpu_online_mask);
+	cpumask_and(pd->cpumask.cbcpu, pinst->cpumask.cbcpu, cpu_online_mask);
+
+	padata_init_reorder_list(pd);
+	padata_init_squeues(pd);
+	pd->seq_nr = -1;
+	refcount_set(&pd->refcnt, 1);
+	spin_lock_init(&pd->lock);
+	pd->cpu = cpumask_first(pd->cpumask.pcpu);
+	INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
+
+	return pd;
+
+err_free_pcpu:
+	free_cpumask_var(pd->cpumask.pcpu);
+err_free_squeue:
+	free_percpu(pd->squeue);
+err_free_reorder_list:
+	free_percpu(pd->reorder_list);
+err_free_pd:
+	kfree(pd);
+err:
+	return NULL;
+}
+
+static void padata_free_pd(struct parallel_data *pd)
+{
+	free_cpumask_var(pd->cpumask.pcpu);
+	free_cpumask_var(pd->cpumask.cbcpu);
+	free_percpu(pd->reorder_list);
+	free_percpu(pd->squeue);
+	kfree(pd);
+}
+
+static void __padata_start(struct padata_instance *pinst)
+{
+	pinst->flags |= PADATA_INIT;
+}
+
+static void __padata_stop(struct padata_instance *pinst)
+{
+	if (!(pinst->flags & PADATA_INIT))
+		return;
+
+	pinst->flags &= ~PADATA_INIT;
+
+	synchronize_rcu();
+}
+
+/* Replace the internal control structure with a new one. */
+static int padata_replace_one(struct padata_shell *ps)
+{
+	struct parallel_data *pd_new;
+
+	pd_new = padata_alloc_pd(ps);
+	if (!pd_new)
+		return -ENOMEM;
+
+	ps->opd = rcu_dereference_protected(ps->pd, 1);
+	rcu_assign_pointer(ps->pd, pd_new);
+
+	return 0;
+}
+
+static int padata_replace(struct padata_instance *pinst)
+{
+	struct padata_shell *ps;
+	int err = 0;
+
+	pinst->flags |= PADATA_RESET;
+
+	list_for_each_entry(ps, &pinst->pslist, list) {
+		err = padata_replace_one(ps);
+		if (err)
+			break;
+	}
+
+	synchronize_rcu();
+
+	list_for_each_entry_continue_reverse(ps, &pinst->pslist, list)
+		if (refcount_dec_and_test(&ps->opd->refcnt))
+			padata_free_pd(ps->opd);
+
+	pinst->flags &= ~PADATA_RESET;
+
+	return err;
+}
+
+/* If cpumask contains no active cpu, we mark the instance as invalid. */
+static bool padata_validate_cpumask(struct padata_instance *pinst,
+				    const struct cpumask *cpumask)
+{
+	if (!cpumask_intersects(cpumask, cpu_online_mask)) {
+		pinst->flags |= PADATA_INVALID;
+		return false;
+	}
+
+	pinst->flags &= ~PADATA_INVALID;
+	return true;
+}
+
+static int __padata_set_cpumasks(struct padata_instance *pinst,
+				 cpumask_var_t pcpumask,
+				 cpumask_var_t cbcpumask)
+{
+	int valid;
+	int err;
+
+	valid = padata_validate_cpumask(pinst, pcpumask);
+	if (!valid) {
+		__padata_stop(pinst);
+		goto out_replace;
+	}
+
+	valid = padata_validate_cpumask(pinst, cbcpumask);
+	if (!valid)
+		__padata_stop(pinst);
+
+out_replace:
+	cpumask_copy(pinst->cpumask.pcpu, pcpumask);
+	cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
+
+	err = padata_setup_cpumasks(pinst) ?: padata_replace(pinst);
+
+	if (valid)
+		__padata_start(pinst);
+
+	return err;
+}
+
+/**
+ * padata_set_cpumask - Sets specified by @cpumask_type cpumask to the value
+ *                      equivalent to @cpumask.
+ * @pinst: padata instance
+ * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
+ *                to parallel and serial cpumasks respectively.
+ * @cpumask: the cpumask to use
+ *
+ * Return: 0 on success or negative error code
+ */
+int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
+		       cpumask_var_t cpumask)
+{
+	struct cpumask *serial_mask, *parallel_mask;
+	int err = -EINVAL;
+
+	cpus_read_lock();
+	mutex_lock(&pinst->lock);
+
+	switch (cpumask_type) {
+	case PADATA_CPU_PARALLEL:
+		serial_mask = pinst->cpumask.cbcpu;
+		parallel_mask = cpumask;
+		break;
+	case PADATA_CPU_SERIAL:
+		parallel_mask = pinst->cpumask.pcpu;
+		serial_mask = cpumask;
+		break;
+	default:
+		 goto out;
+	}
+
+	err =  __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
+
+out:
+	mutex_unlock(&pinst->lock);
+	cpus_read_unlock();
+
+	return err;
+}
+EXPORT_SYMBOL(padata_set_cpumask);
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
+{
+	int err = 0;
+
+	if (cpumask_test_cpu(cpu, cpu_online_mask)) {
+		err = padata_replace(pinst);
+
+		if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
+		    padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
+			__padata_start(pinst);
+	}
+
+	return err;
+}
+
+static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
+{
+	int err = 0;
+
+	if (!cpumask_test_cpu(cpu, cpu_online_mask)) {
+		if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
+		    !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
+			__padata_stop(pinst);
+
+		err = padata_replace(pinst);
+	}
+
+	return err;
+}
+
+static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
+{
+	return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
+		cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
+}
+
+static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
+{
+	struct padata_instance *pinst;
+	int ret;
+
+	pinst = hlist_entry_safe(node, struct padata_instance, cpu_online_node);
+	if (!pinst_has_cpu(pinst, cpu))
+		return 0;
+
+	mutex_lock(&pinst->lock);
+	ret = __padata_add_cpu(pinst, cpu);
+	mutex_unlock(&pinst->lock);
+	return ret;
+}
+
+static int padata_cpu_dead(unsigned int cpu, struct hlist_node *node)
+{
+	struct padata_instance *pinst;
+	int ret;
+
+	pinst = hlist_entry_safe(node, struct padata_instance, cpu_dead_node);
+	if (!pinst_has_cpu(pinst, cpu))
+		return 0;
+
+	mutex_lock(&pinst->lock);
+	ret = __padata_remove_cpu(pinst, cpu);
+	mutex_unlock(&pinst->lock);
+	return ret;
+}
+
+static enum cpuhp_state hp_online;
+#endif
+
+static void __padata_free(struct padata_instance *pinst)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+	cpuhp_state_remove_instance_nocalls(CPUHP_PADATA_DEAD,
+					    &pinst->cpu_dead_node);
+	cpuhp_state_remove_instance_nocalls(hp_online, &pinst->cpu_online_node);
+#endif
+
+	WARN_ON(!list_empty(&pinst->pslist));
+
+	free_cpumask_var(pinst->cpumask.pcpu);
+	free_cpumask_var(pinst->cpumask.cbcpu);
+	destroy_workqueue(pinst->serial_wq);
+	destroy_workqueue(pinst->parallel_wq);
+	kfree(pinst);
+}
+
+#define kobj2pinst(_kobj)					\
+	container_of(_kobj, struct padata_instance, kobj)
+#define attr2pentry(_attr)					\
+	container_of(_attr, struct padata_sysfs_entry, attr)
+
+static void padata_sysfs_release(struct kobject *kobj)
+{
+	struct padata_instance *pinst = kobj2pinst(kobj);
+	__padata_free(pinst);
+}
+
+struct padata_sysfs_entry {
+	struct attribute attr;
+	ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
+	ssize_t (*store)(struct padata_instance *, struct attribute *,
+			 const char *, size_t);
+};
+
+static ssize_t show_cpumask(struct padata_instance *pinst,
+			    struct attribute *attr,  char *buf)
+{
+	struct cpumask *cpumask;
+	ssize_t len;
+
+	mutex_lock(&pinst->lock);
+	if (!strcmp(attr->name, "serial_cpumask"))
+		cpumask = pinst->cpumask.cbcpu;
+	else
+		cpumask = pinst->cpumask.pcpu;
+
+	len = snprintf(buf, PAGE_SIZE, "%*pb\n",
+		       nr_cpu_ids, cpumask_bits(cpumask));
+	mutex_unlock(&pinst->lock);
+	return len < PAGE_SIZE ? len : -EINVAL;
+}
+
+static ssize_t store_cpumask(struct padata_instance *pinst,
+			     struct attribute *attr,
+			     const char *buf, size_t count)
+{
+	cpumask_var_t new_cpumask;
+	ssize_t ret;
+	int mask_type;
+
+	if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
+		return -ENOMEM;
+
+	ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
+			   nr_cpumask_bits);
+	if (ret < 0)
+		goto out;
+
+	mask_type = !strcmp(attr->name, "serial_cpumask") ?
+		PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
+	ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
+	if (!ret)
+		ret = count;
+
+out:
+	free_cpumask_var(new_cpumask);
+	return ret;
+}
+
+#define PADATA_ATTR_RW(_name, _show_name, _store_name)		\
+	static struct padata_sysfs_entry _name##_attr =		\
+		__ATTR(_name, 0644, _show_name, _store_name)
+#define PADATA_ATTR_RO(_name, _show_name)		\
+	static struct padata_sysfs_entry _name##_attr = \
+		__ATTR(_name, 0400, _show_name, NULL)
+
+PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
+PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
+
+/*
+ * Padata sysfs provides the following objects:
+ * serial_cpumask   [RW] - cpumask for serial workers
+ * parallel_cpumask [RW] - cpumask for parallel workers
+ */
+static struct attribute *padata_default_attrs[] = {
+	&serial_cpumask_attr.attr,
+	&parallel_cpumask_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(padata_default);
+
+static ssize_t padata_sysfs_show(struct kobject *kobj,
+				 struct attribute *attr, char *buf)
+{
+	struct padata_instance *pinst;
+	struct padata_sysfs_entry *pentry;
+	ssize_t ret = -EIO;
+
+	pinst = kobj2pinst(kobj);
+	pentry = attr2pentry(attr);
+	if (pentry->show)
+		ret = pentry->show(pinst, attr, buf);
+
+	return ret;
+}
+
+static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
+				  const char *buf, size_t count)
+{
+	struct padata_instance *pinst;
+	struct padata_sysfs_entry *pentry;
+	ssize_t ret = -EIO;
+
+	pinst = kobj2pinst(kobj);
+	pentry = attr2pentry(attr);
+	if (pentry->show)
+		ret = pentry->store(pinst, attr, buf, count);
+
+	return ret;
+}
+
+static const struct sysfs_ops padata_sysfs_ops = {
+	.show = padata_sysfs_show,
+	.store = padata_sysfs_store,
+};
+
+static struct kobj_type padata_attr_type = {
+	.sysfs_ops = &padata_sysfs_ops,
+	.default_groups = padata_default_groups,
+	.release = padata_sysfs_release,
+};
+
+/**
+ * padata_alloc - allocate and initialize a padata instance
+ * @name: used to identify the instance
+ *
+ * Return: new instance on success, NULL on error
+ */
+struct padata_instance *padata_alloc(const char *name)
+{
+	struct padata_instance *pinst;
+
+	pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
+	if (!pinst)
+		goto err;
+
+	pinst->parallel_wq = alloc_workqueue("%s_parallel", WQ_UNBOUND, 0,
+					     name);
+	if (!pinst->parallel_wq)
+		goto err_free_inst;
+
+	cpus_read_lock();
+
+	pinst->serial_wq = alloc_workqueue("%s_serial", WQ_MEM_RECLAIM |
+					   WQ_CPU_INTENSIVE, 1, name);
+	if (!pinst->serial_wq)
+		goto err_put_cpus;
+
+	if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
+		goto err_free_serial_wq;
+	if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
+		free_cpumask_var(pinst->cpumask.pcpu);
+		goto err_free_serial_wq;
+	}
+
+	INIT_LIST_HEAD(&pinst->pslist);
+
+	cpumask_copy(pinst->cpumask.pcpu, cpu_possible_mask);
+	cpumask_copy(pinst->cpumask.cbcpu, cpu_possible_mask);
+
+	if (padata_setup_cpumasks(pinst))
+		goto err_free_masks;
+
+	__padata_start(pinst);
+
+	kobject_init(&pinst->kobj, &padata_attr_type);
+	mutex_init(&pinst->lock);
+
+#ifdef CONFIG_HOTPLUG_CPU
+	cpuhp_state_add_instance_nocalls_cpuslocked(hp_online,
+						    &pinst->cpu_online_node);
+	cpuhp_state_add_instance_nocalls_cpuslocked(CPUHP_PADATA_DEAD,
+						    &pinst->cpu_dead_node);
+#endif
+
+	cpus_read_unlock();
+
+	return pinst;
+
+err_free_masks:
+	free_cpumask_var(pinst->cpumask.pcpu);
+	free_cpumask_var(pinst->cpumask.cbcpu);
+err_free_serial_wq:
+	destroy_workqueue(pinst->serial_wq);
+err_put_cpus:
+	cpus_read_unlock();
+	destroy_workqueue(pinst->parallel_wq);
+err_free_inst:
+	kfree(pinst);
+err:
+	return NULL;
+}
+EXPORT_SYMBOL(padata_alloc);
+
+/**
+ * padata_free - free a padata instance
+ *
+ * @pinst: padata instance to free
+ */
+void padata_free(struct padata_instance *pinst)
+{
+	kobject_put(&pinst->kobj);
+}
+EXPORT_SYMBOL(padata_free);
+
+/**
+ * padata_alloc_shell - Allocate and initialize padata shell.
+ *
+ * @pinst: Parent padata_instance object.
+ *
+ * Return: new shell on success, NULL on error
+ */
+struct padata_shell *padata_alloc_shell(struct padata_instance *pinst)
+{
+	struct parallel_data *pd;
+	struct padata_shell *ps;
+
+	ps = kzalloc(sizeof(*ps), GFP_KERNEL);
+	if (!ps)
+		goto out;
+
+	ps->pinst = pinst;
+
+	cpus_read_lock();
+	pd = padata_alloc_pd(ps);
+	cpus_read_unlock();
+
+	if (!pd)
+		goto out_free_ps;
+
+	mutex_lock(&pinst->lock);
+	RCU_INIT_POINTER(ps->pd, pd);
+	list_add(&ps->list, &pinst->pslist);
+	mutex_unlock(&pinst->lock);
+
+	return ps;
+
+out_free_ps:
+	kfree(ps);
+out:
+	return NULL;
+}
+EXPORT_SYMBOL(padata_alloc_shell);
+
+/**
+ * padata_free_shell - free a padata shell
+ *
+ * @ps: padata shell to free
+ */
+void padata_free_shell(struct padata_shell *ps)
+{
+	struct parallel_data *pd;
+
+	if (!ps)
+		return;
+
+	mutex_lock(&ps->pinst->lock);
+	list_del(&ps->list);
+	pd = rcu_dereference_protected(ps->pd, 1);
+	if (refcount_dec_and_test(&pd->refcnt))
+		padata_free_pd(pd);
+	mutex_unlock(&ps->pinst->lock);
+
+	kfree(ps);
+}
+EXPORT_SYMBOL(padata_free_shell);
+
+void __init padata_init(void)
+{
+	unsigned int i, possible_cpus;
+#ifdef CONFIG_HOTPLUG_CPU
+	int ret;
+
+	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
+				      padata_cpu_online, NULL);
+	if (ret < 0)
+		goto err;
+	hp_online = ret;
+
+	ret = cpuhp_setup_state_multi(CPUHP_PADATA_DEAD, "padata:dead",
+				      NULL, padata_cpu_dead);
+	if (ret < 0)
+		goto remove_online_state;
+#endif
+
+	possible_cpus = num_possible_cpus();
+	padata_works = kmalloc_array(possible_cpus, sizeof(struct padata_work),
+				     GFP_KERNEL);
+	if (!padata_works)
+		goto remove_dead_state;
+
+	for (i = 0; i < possible_cpus; ++i)
+		list_add(&padata_works[i].pw_list, &padata_free_works);
+
+	return;
+
+remove_dead_state:
+#ifdef CONFIG_HOTPLUG_CPU
+	cpuhp_remove_multi_state(CPUHP_PADATA_DEAD);
+remove_online_state:
+	cpuhp_remove_multi_state(hp_online);
+err:
+#endif
+	pr_warn("padata: initialization failed\n");
+}
diff --git a/kernel/panic.c b/kernel/panic.c
new file mode 100644
index 000000000..63e94f3bd
--- /dev/null
+++ b/kernel/panic.c
@@ -0,0 +1,808 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/kernel/panic.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+/*
+ * This function is used through-out the kernel (including mm and fs)
+ * to indicate a major problem.
+ */
+#include <linux/debug_locks.h>
+#include <linux/sched/debug.h>
+#include <linux/interrupt.h>
+#include <linux/kgdb.h>
+#include <linux/kmsg_dump.h>
+#include <linux/kallsyms.h>
+#include <linux/notifier.h>
+#include <linux/vt_kern.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/ftrace.h>
+#include <linux/reboot.h>
+#include <linux/delay.h>
+#include <linux/kexec.h>
+#include <linux/panic_notifier.h>
+#include <linux/sched.h>
+#include <linux/sysrq.h>
+#include <linux/init.h>
+#include <linux/nmi.h>
+#include <linux/console.h>
+#include <linux/bug.h>
+#include <linux/ratelimit.h>
+#include <linux/debugfs.h>
+#include <linux/sysfs.h>
+#include <linux/context_tracking.h>
+#include <trace/events/error_report.h>
+#include <asm/sections.h>
+
+#define PANIC_TIMER_STEP 100
+#define PANIC_BLINK_SPD 18
+
+#ifdef CONFIG_SMP
+/*
+ * Should we dump all CPUs backtraces in an oops event?
+ * Defaults to 0, can be changed via sysctl.
+ */
+static unsigned int __read_mostly sysctl_oops_all_cpu_backtrace;
+#else
+#define sysctl_oops_all_cpu_backtrace 0
+#endif /* CONFIG_SMP */
+
+int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
+static unsigned long tainted_mask =
+	IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0;
+static int pause_on_oops;
+static int pause_on_oops_flag;
+static DEFINE_SPINLOCK(pause_on_oops_lock);
+bool crash_kexec_post_notifiers;
+int panic_on_warn __read_mostly;
+unsigned long panic_on_taint;
+bool panic_on_taint_nousertaint = false;
+static unsigned int warn_limit __read_mostly;
+
+int panic_timeout = CONFIG_PANIC_TIMEOUT;
+EXPORT_SYMBOL_GPL(panic_timeout);
+
+#define PANIC_PRINT_TASK_INFO		0x00000001
+#define PANIC_PRINT_MEM_INFO		0x00000002
+#define PANIC_PRINT_TIMER_INFO		0x00000004
+#define PANIC_PRINT_LOCK_INFO		0x00000008
+#define PANIC_PRINT_FTRACE_INFO		0x00000010
+#define PANIC_PRINT_ALL_PRINTK_MSG	0x00000020
+#define PANIC_PRINT_ALL_CPU_BT		0x00000040
+unsigned long panic_print;
+
+ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
+
+EXPORT_SYMBOL(panic_notifier_list);
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table kern_panic_table[] = {
+#ifdef CONFIG_SMP
+	{
+		.procname       = "oops_all_cpu_backtrace",
+		.data           = &sysctl_oops_all_cpu_backtrace,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec_minmax,
+		.extra1         = SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE,
+	},
+#endif
+	{
+		.procname       = "warn_limit",
+		.data           = &warn_limit,
+		.maxlen         = sizeof(warn_limit),
+		.mode           = 0644,
+		.proc_handler   = proc_douintvec,
+	},
+	{ }
+};
+
+static __init int kernel_panic_sysctls_init(void)
+{
+	register_sysctl_init("kernel", kern_panic_table);
+	return 0;
+}
+late_initcall(kernel_panic_sysctls_init);
+#endif
+
+static atomic_t warn_count = ATOMIC_INIT(0);
+
+#ifdef CONFIG_SYSFS
+static ssize_t warn_count_show(struct kobject *kobj, struct kobj_attribute *attr,
+			       char *page)
+{
+	return sysfs_emit(page, "%d\n", atomic_read(&warn_count));
+}
+
+static struct kobj_attribute warn_count_attr = __ATTR_RO(warn_count);
+
+static __init int kernel_panic_sysfs_init(void)
+{
+	sysfs_add_file_to_group(kernel_kobj, &warn_count_attr.attr, NULL);
+	return 0;
+}
+late_initcall(kernel_panic_sysfs_init);
+#endif
+
+static long no_blink(int state)
+{
+	return 0;
+}
+
+/* Returns how long it waited in ms */
+long (*panic_blink)(int state);
+EXPORT_SYMBOL(panic_blink);
+
+/*
+ * Stop ourself in panic -- architecture code may override this
+ */
+void __weak panic_smp_self_stop(void)
+{
+	while (1)
+		cpu_relax();
+}
+
+/*
+ * Stop ourselves in NMI context if another CPU has already panicked. Arch code
+ * may override this to prepare for crash dumping, e.g. save regs info.
+ */
+void __weak nmi_panic_self_stop(struct pt_regs *regs)
+{
+	panic_smp_self_stop();
+}
+
+/*
+ * Stop other CPUs in panic.  Architecture dependent code may override this
+ * with more suitable version.  For example, if the architecture supports
+ * crash dump, it should save registers of each stopped CPU and disable
+ * per-CPU features such as virtualization extensions.
+ */
+void __weak crash_smp_send_stop(void)
+{
+	static int cpus_stopped;
+
+	/*
+	 * This function can be called twice in panic path, but obviously
+	 * we execute this only once.
+	 */
+	if (cpus_stopped)
+		return;
+
+	/*
+	 * Note smp_send_stop is the usual smp shutdown function, which
+	 * unfortunately means it may not be hardened to work in a panic
+	 * situation.
+	 */
+	smp_send_stop();
+	cpus_stopped = 1;
+}
+
+atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID);
+
+/*
+ * A variant of panic() called from NMI context. We return if we've already
+ * panicked on this CPU. If another CPU already panicked, loop in
+ * nmi_panic_self_stop() which can provide architecture dependent code such
+ * as saving register state for crash dump.
+ */
+void nmi_panic(struct pt_regs *regs, const char *msg)
+{
+	int old_cpu, cpu;
+
+	cpu = raw_smp_processor_id();
+	old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu);
+
+	if (old_cpu == PANIC_CPU_INVALID)
+		panic("%s", msg);
+	else if (old_cpu != cpu)
+		nmi_panic_self_stop(regs);
+}
+EXPORT_SYMBOL(nmi_panic);
+
+static void panic_print_sys_info(bool console_flush)
+{
+	if (console_flush) {
+		if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG)
+			console_flush_on_panic(CONSOLE_REPLAY_ALL);
+		return;
+	}
+
+	if (panic_print & PANIC_PRINT_TASK_INFO)
+		show_state();
+
+	if (panic_print & PANIC_PRINT_MEM_INFO)
+		show_mem(0, NULL);
+
+	if (panic_print & PANIC_PRINT_TIMER_INFO)
+		sysrq_timer_list_show();
+
+	if (panic_print & PANIC_PRINT_LOCK_INFO)
+		debug_show_all_locks();
+
+	if (panic_print & PANIC_PRINT_FTRACE_INFO)
+		ftrace_dump(DUMP_ALL);
+}
+
+void check_panic_on_warn(const char *origin)
+{
+	unsigned int limit;
+
+	if (panic_on_warn)
+		panic("%s: panic_on_warn set ...\n", origin);
+
+	limit = READ_ONCE(warn_limit);
+	if (atomic_inc_return(&warn_count) >= limit && limit)
+		panic("%s: system warned too often (kernel.warn_limit is %d)",
+		      origin, limit);
+}
+
+/*
+ * Helper that triggers the NMI backtrace (if set in panic_print)
+ * and then performs the secondary CPUs shutdown - we cannot have
+ * the NMI backtrace after the CPUs are off!
+ */
+static void panic_other_cpus_shutdown(bool crash_kexec)
+{
+	if (panic_print & PANIC_PRINT_ALL_CPU_BT)
+		trigger_all_cpu_backtrace();
+
+	/*
+	 * Note that smp_send_stop() is the usual SMP shutdown function,
+	 * which unfortunately may not be hardened to work in a panic
+	 * situation. If we want to do crash dump after notifier calls
+	 * and kmsg_dump, we will need architecture dependent extra
+	 * bits in addition to stopping other CPUs, hence we rely on
+	 * crash_smp_send_stop() for that.
+	 */
+	if (!crash_kexec)
+		smp_send_stop();
+	else
+		crash_smp_send_stop();
+}
+
+/**
+ *	panic - halt the system
+ *	@fmt: The text string to print
+ *
+ *	Display a message, then perform cleanups.
+ *
+ *	This function never returns.
+ */
+void panic(const char *fmt, ...)
+{
+	static char buf[1024];
+	va_list args;
+	long i, i_next = 0, len;
+	int state = 0;
+	int old_cpu, this_cpu;
+	bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers;
+
+	if (panic_on_warn) {
+		/*
+		 * This thread may hit another WARN() in the panic path.
+		 * Resetting this prevents additional WARN() from panicking the
+		 * system on this thread.  Other threads are blocked by the
+		 * panic_mutex in panic().
+		 */
+		panic_on_warn = 0;
+	}
+
+	/*
+	 * Disable local interrupts. This will prevent panic_smp_self_stop
+	 * from deadlocking the first cpu that invokes the panic, since
+	 * there is nothing to prevent an interrupt handler (that runs
+	 * after setting panic_cpu) from invoking panic() again.
+	 */
+	local_irq_disable();
+	preempt_disable_notrace();
+
+	/*
+	 * It's possible to come here directly from a panic-assertion and
+	 * not have preempt disabled. Some functions called from here want
+	 * preempt to be disabled. No point enabling it later though...
+	 *
+	 * Only one CPU is allowed to execute the panic code from here. For
+	 * multiple parallel invocations of panic, all other CPUs either
+	 * stop themself or will wait until they are stopped by the 1st CPU
+	 * with smp_send_stop().
+	 *
+	 * `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which
+	 * comes here, so go ahead.
+	 * `old_cpu == this_cpu' means we came from nmi_panic() which sets
+	 * panic_cpu to this CPU.  In this case, this is also the 1st CPU.
+	 */
+	this_cpu = raw_smp_processor_id();
+	old_cpu  = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
+
+	if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu)
+		panic_smp_self_stop();
+
+	console_verbose();
+	bust_spinlocks(1);
+	va_start(args, fmt);
+	len = vscnprintf(buf, sizeof(buf), fmt, args);
+	va_end(args);
+
+	if (len && buf[len - 1] == '\n')
+		buf[len - 1] = '\0';
+
+	pr_emerg("Kernel panic - not syncing: %s\n", buf);
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+	/*
+	 * Avoid nested stack-dumping if a panic occurs during oops processing
+	 */
+	if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
+		dump_stack();
+#endif
+
+	/*
+	 * If kgdb is enabled, give it a chance to run before we stop all
+	 * the other CPUs or else we won't be able to debug processes left
+	 * running on them.
+	 */
+	kgdb_panic(buf);
+
+	/*
+	 * If we have crashed and we have a crash kernel loaded let it handle
+	 * everything else.
+	 * If we want to run this after calling panic_notifiers, pass
+	 * the "crash_kexec_post_notifiers" option to the kernel.
+	 *
+	 * Bypass the panic_cpu check and call __crash_kexec directly.
+	 */
+	if (!_crash_kexec_post_notifiers)
+		__crash_kexec(NULL);
+
+	panic_other_cpus_shutdown(_crash_kexec_post_notifiers);
+
+	/*
+	 * Run any panic handlers, including those that might need to
+	 * add information to the kmsg dump output.
+	 */
+	atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
+
+	panic_print_sys_info(false);
+
+	kmsg_dump(KMSG_DUMP_PANIC);
+
+	/*
+	 * If you doubt kdump always works fine in any situation,
+	 * "crash_kexec_post_notifiers" offers you a chance to run
+	 * panic_notifiers and dumping kmsg before kdump.
+	 * Note: since some panic_notifiers can make crashed kernel
+	 * more unstable, it can increase risks of the kdump failure too.
+	 *
+	 * Bypass the panic_cpu check and call __crash_kexec directly.
+	 */
+	if (_crash_kexec_post_notifiers)
+		__crash_kexec(NULL);
+
+	console_unblank();
+
+	/*
+	 * We may have ended up stopping the CPU holding the lock (in
+	 * smp_send_stop()) while still having some valuable data in the console
+	 * buffer.  Try to acquire the lock then release it regardless of the
+	 * result.  The release will also print the buffers out.  Locks debug
+	 * should be disabled to avoid reporting bad unlock balance when
+	 * panic() is not being callled from OOPS.
+	 */
+	debug_locks_off();
+	console_flush_on_panic(CONSOLE_FLUSH_PENDING);
+
+	panic_print_sys_info(true);
+
+	if (!panic_blink)
+		panic_blink = no_blink;
+
+	if (panic_timeout > 0) {
+		/*
+		 * Delay timeout seconds before rebooting the machine.
+		 * We can't use the "normal" timers since we just panicked.
+		 */
+		pr_emerg("Rebooting in %d seconds..\n", panic_timeout);
+
+		for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
+			touch_nmi_watchdog();
+			if (i >= i_next) {
+				i += panic_blink(state ^= 1);
+				i_next = i + 3600 / PANIC_BLINK_SPD;
+			}
+			mdelay(PANIC_TIMER_STEP);
+		}
+	}
+	if (panic_timeout != 0) {
+		/*
+		 * This will not be a clean reboot, with everything
+		 * shutting down.  But if there is a chance of
+		 * rebooting the system it will be rebooted.
+		 */
+		if (panic_reboot_mode != REBOOT_UNDEFINED)
+			reboot_mode = panic_reboot_mode;
+		emergency_restart();
+	}
+#ifdef __sparc__
+	{
+		extern int stop_a_enabled;
+		/* Make sure the user can actually press Stop-A (L1-A) */
+		stop_a_enabled = 1;
+		pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n"
+			 "twice on console to return to the boot prom\n");
+	}
+#endif
+#if defined(CONFIG_S390)
+	disabled_wait();
+#endif
+	pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf);
+
+	/* Do not scroll important messages printed above */
+	suppress_printk = 1;
+	local_irq_enable();
+	for (i = 0; ; i += PANIC_TIMER_STEP) {
+		touch_softlockup_watchdog();
+		if (i >= i_next) {
+			i += panic_blink(state ^= 1);
+			i_next = i + 3600 / PANIC_BLINK_SPD;
+		}
+		mdelay(PANIC_TIMER_STEP);
+	}
+}
+
+EXPORT_SYMBOL(panic);
+
+/*
+ * TAINT_FORCED_RMMOD could be a per-module flag but the module
+ * is being removed anyway.
+ */
+const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
+	[ TAINT_PROPRIETARY_MODULE ]	= { 'P', 'G', true },
+	[ TAINT_FORCED_MODULE ]		= { 'F', ' ', true },
+	[ TAINT_CPU_OUT_OF_SPEC ]	= { 'S', ' ', false },
+	[ TAINT_FORCED_RMMOD ]		= { 'R', ' ', false },
+	[ TAINT_MACHINE_CHECK ]		= { 'M', ' ', false },
+	[ TAINT_BAD_PAGE ]		= { 'B', ' ', false },
+	[ TAINT_USER ]			= { 'U', ' ', false },
+	[ TAINT_DIE ]			= { 'D', ' ', false },
+	[ TAINT_OVERRIDDEN_ACPI_TABLE ]	= { 'A', ' ', false },
+	[ TAINT_WARN ]			= { 'W', ' ', false },
+	[ TAINT_CRAP ]			= { 'C', ' ', true },
+	[ TAINT_FIRMWARE_WORKAROUND ]	= { 'I', ' ', false },
+	[ TAINT_OOT_MODULE ]		= { 'O', ' ', true },
+	[ TAINT_UNSIGNED_MODULE ]	= { 'E', ' ', true },
+	[ TAINT_SOFTLOCKUP ]		= { 'L', ' ', false },
+	[ TAINT_LIVEPATCH ]		= { 'K', ' ', true },
+	[ TAINT_AUX ]			= { 'X', ' ', true },
+	[ TAINT_RANDSTRUCT ]		= { 'T', ' ', true },
+	[ TAINT_TEST ]			= { 'N', ' ', true },
+};
+
+/**
+ * print_tainted - return a string to represent the kernel taint state.
+ *
+ * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst
+ *
+ * The string is overwritten by the next call to print_tainted(),
+ * but is always NULL terminated.
+ */
+const char *print_tainted(void)
+{
+	static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")];
+
+	BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);
+
+	if (tainted_mask) {
+		char *s;
+		int i;
+
+		s = buf + sprintf(buf, "Tainted: ");
+		for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
+			const struct taint_flag *t = &taint_flags[i];
+			*s++ = test_bit(i, &tainted_mask) ?
+					t->c_true : t->c_false;
+		}
+		*s = 0;
+	} else
+		snprintf(buf, sizeof(buf), "Not tainted");
+
+	return buf;
+}
+
+int test_taint(unsigned flag)
+{
+	return test_bit(flag, &tainted_mask);
+}
+EXPORT_SYMBOL(test_taint);
+
+unsigned long get_taint(void)
+{
+	return tainted_mask;
+}
+
+/**
+ * add_taint: add a taint flag if not already set.
+ * @flag: one of the TAINT_* constants.
+ * @lockdep_ok: whether lock debugging is still OK.
+ *
+ * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
+ * some notewortht-but-not-corrupting cases, it can be set to true.
+ */
+void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
+{
+	if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
+		pr_warn("Disabling lock debugging due to kernel taint\n");
+
+	set_bit(flag, &tainted_mask);
+
+	if (tainted_mask & panic_on_taint) {
+		panic_on_taint = 0;
+		panic("panic_on_taint set ...");
+	}
+}
+EXPORT_SYMBOL(add_taint);
+
+static void spin_msec(int msecs)
+{
+	int i;
+
+	for (i = 0; i < msecs; i++) {
+		touch_nmi_watchdog();
+		mdelay(1);
+	}
+}
+
+/*
+ * It just happens that oops_enter() and oops_exit() are identically
+ * implemented...
+ */
+static void do_oops_enter_exit(void)
+{
+	unsigned long flags;
+	static int spin_counter;
+
+	if (!pause_on_oops)
+		return;
+
+	spin_lock_irqsave(&pause_on_oops_lock, flags);
+	if (pause_on_oops_flag == 0) {
+		/* This CPU may now print the oops message */
+		pause_on_oops_flag = 1;
+	} else {
+		/* We need to stall this CPU */
+		if (!spin_counter) {
+			/* This CPU gets to do the counting */
+			spin_counter = pause_on_oops;
+			do {
+				spin_unlock(&pause_on_oops_lock);
+				spin_msec(MSEC_PER_SEC);
+				spin_lock(&pause_on_oops_lock);
+			} while (--spin_counter);
+			pause_on_oops_flag = 0;
+		} else {
+			/* This CPU waits for a different one */
+			while (spin_counter) {
+				spin_unlock(&pause_on_oops_lock);
+				spin_msec(1);
+				spin_lock(&pause_on_oops_lock);
+			}
+		}
+	}
+	spin_unlock_irqrestore(&pause_on_oops_lock, flags);
+}
+
+/*
+ * Return true if the calling CPU is allowed to print oops-related info.
+ * This is a bit racy..
+ */
+bool oops_may_print(void)
+{
+	return pause_on_oops_flag == 0;
+}
+
+/*
+ * Called when the architecture enters its oops handler, before it prints
+ * anything.  If this is the first CPU to oops, and it's oopsing the first
+ * time then let it proceed.
+ *
+ * This is all enabled by the pause_on_oops kernel boot option.  We do all
+ * this to ensure that oopses don't scroll off the screen.  It has the
+ * side-effect of preventing later-oopsing CPUs from mucking up the display,
+ * too.
+ *
+ * It turns out that the CPU which is allowed to print ends up pausing for
+ * the right duration, whereas all the other CPUs pause for twice as long:
+ * once in oops_enter(), once in oops_exit().
+ */
+void oops_enter(void)
+{
+	tracing_off();
+	/* can't trust the integrity of the kernel anymore: */
+	debug_locks_off();
+	do_oops_enter_exit();
+
+	if (sysctl_oops_all_cpu_backtrace)
+		trigger_all_cpu_backtrace();
+}
+
+static void print_oops_end_marker(void)
+{
+	pr_warn("---[ end trace %016llx ]---\n", 0ULL);
+}
+
+/*
+ * Called when the architecture exits its oops handler, after printing
+ * everything.
+ */
+void oops_exit(void)
+{
+	do_oops_enter_exit();
+	print_oops_end_marker();
+	kmsg_dump(KMSG_DUMP_OOPS);
+}
+
+struct warn_args {
+	const char *fmt;
+	va_list args;
+};
+
+void __warn(const char *file, int line, void *caller, unsigned taint,
+	    struct pt_regs *regs, struct warn_args *args)
+{
+	disable_trace_on_warning();
+
+	if (file)
+		pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n",
+			raw_smp_processor_id(), current->pid, file, line,
+			caller);
+	else
+		pr_warn("WARNING: CPU: %d PID: %d at %pS\n",
+			raw_smp_processor_id(), current->pid, caller);
+
+	if (args)
+		vprintk(args->fmt, args->args);
+
+	print_modules();
+
+	if (regs)
+		show_regs(regs);
+
+	check_panic_on_warn("kernel");
+
+	if (!regs)
+		dump_stack();
+
+	print_irqtrace_events(current);
+
+	print_oops_end_marker();
+	trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller);
+
+	/* Just a warning, don't kill lockdep. */
+	add_taint(taint, LOCKDEP_STILL_OK);
+}
+
+#ifndef __WARN_FLAGS
+void warn_slowpath_fmt(const char *file, int line, unsigned taint,
+		       const char *fmt, ...)
+{
+	bool rcu = warn_rcu_enter();
+	struct warn_args args;
+
+	pr_warn(CUT_HERE);
+
+	if (!fmt) {
+		__warn(file, line, __builtin_return_address(0), taint,
+		       NULL, NULL);
+		warn_rcu_exit(rcu);
+		return;
+	}
+
+	args.fmt = fmt;
+	va_start(args.args, fmt);
+	__warn(file, line, __builtin_return_address(0), taint, NULL, &args);
+	va_end(args.args);
+	warn_rcu_exit(rcu);
+}
+EXPORT_SYMBOL(warn_slowpath_fmt);
+#else
+void __warn_printk(const char *fmt, ...)
+{
+	bool rcu = warn_rcu_enter();
+	va_list args;
+
+	pr_warn(CUT_HERE);
+
+	va_start(args, fmt);
+	vprintk(fmt, args);
+	va_end(args);
+	warn_rcu_exit(rcu);
+}
+EXPORT_SYMBOL(__warn_printk);
+#endif
+
+#ifdef CONFIG_BUG
+
+/* Support resetting WARN*_ONCE state */
+
+static int clear_warn_once_set(void *data, u64 val)
+{
+	generic_bug_clear_once();
+	memset(__start_once, 0, __end_once - __start_once);
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set,
+			 "%lld\n");
+
+static __init int register_warn_debugfs(void)
+{
+	/* Don't care about failure */
+	debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL,
+				   &clear_warn_once_fops);
+	return 0;
+}
+
+device_initcall(register_warn_debugfs);
+#endif
+
+#ifdef CONFIG_STACKPROTECTOR
+
+/*
+ * Called when gcc's -fstack-protector feature is used, and
+ * gcc detects corruption of the on-stack canary value
+ */
+__visible noinstr void __stack_chk_fail(void)
+{
+	instrumentation_begin();
+	panic("stack-protector: Kernel stack is corrupted in: %pB",
+		__builtin_return_address(0));
+	instrumentation_end();
+}
+EXPORT_SYMBOL(__stack_chk_fail);
+
+#endif
+
+core_param(panic, panic_timeout, int, 0644);
+core_param(panic_print, panic_print, ulong, 0644);
+core_param(pause_on_oops, pause_on_oops, int, 0644);
+core_param(panic_on_warn, panic_on_warn, int, 0644);
+core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644);
+
+static int __init oops_setup(char *s)
+{
+	if (!s)
+		return -EINVAL;
+	if (!strcmp(s, "panic"))
+		panic_on_oops = 1;
+	return 0;
+}
+early_param("oops", oops_setup);
+
+static int __init panic_on_taint_setup(char *s)
+{
+	char *taint_str;
+
+	if (!s)
+		return -EINVAL;
+
+	taint_str = strsep(&s, ",");
+	if (kstrtoul(taint_str, 16, &panic_on_taint))
+		return -EINVAL;
+
+	/* make sure panic_on_taint doesn't hold out-of-range TAINT flags */
+	panic_on_taint &= TAINT_FLAGS_MAX;
+
+	if (!panic_on_taint)
+		return -EINVAL;
+
+	if (s && !strcmp(s, "nousertaint"))
+		panic_on_taint_nousertaint = true;
+
+	pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%sabled\n",
+		panic_on_taint, panic_on_taint_nousertaint ? "en" : "dis");
+
+	return 0;
+}
+early_param("panic_on_taint", panic_on_taint_setup);
diff --git a/kernel/params.c b/kernel/params.c
new file mode 100644
index 000000000..5b9231042
--- /dev/null
+++ b/kernel/params.c
@@ -0,0 +1,976 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Helpers for initial module or kernel cmdline parsing
+   Copyright (C) 2001 Rusty Russell.
+
+*/
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/ctype.h>
+#include <linux/security.h>
+
+#ifdef CONFIG_SYSFS
+/* Protects all built-in parameters, modules use their own param_lock */
+static DEFINE_MUTEX(param_lock);
+
+/* Use the module's mutex, or if built-in use the built-in mutex */
+#ifdef CONFIG_MODULES
+#define KPARAM_MUTEX(mod)	((mod) ? &(mod)->param_lock : &param_lock)
+#else
+#define KPARAM_MUTEX(mod)	(&param_lock)
+#endif
+
+static inline void check_kparam_locked(struct module *mod)
+{
+	BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod)));
+}
+#else
+static inline void check_kparam_locked(struct module *mod)
+{
+}
+#endif /* !CONFIG_SYSFS */
+
+/* This just allows us to keep track of which parameters are kmalloced. */
+struct kmalloced_param {
+	struct list_head list;
+	char val[];
+};
+static LIST_HEAD(kmalloced_params);
+static DEFINE_SPINLOCK(kmalloced_params_lock);
+
+static void *kmalloc_parameter(unsigned int size)
+{
+	struct kmalloced_param *p;
+
+	p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
+	if (!p)
+		return NULL;
+
+	spin_lock(&kmalloced_params_lock);
+	list_add(&p->list, &kmalloced_params);
+	spin_unlock(&kmalloced_params_lock);
+
+	return p->val;
+}
+
+/* Does nothing if parameter wasn't kmalloced above. */
+static void maybe_kfree_parameter(void *param)
+{
+	struct kmalloced_param *p;
+
+	spin_lock(&kmalloced_params_lock);
+	list_for_each_entry(p, &kmalloced_params, list) {
+		if (p->val == param) {
+			list_del(&p->list);
+			kfree(p);
+			break;
+		}
+	}
+	spin_unlock(&kmalloced_params_lock);
+}
+
+static char dash2underscore(char c)
+{
+	if (c == '-')
+		return '_';
+	return c;
+}
+
+bool parameqn(const char *a, const char *b, size_t n)
+{
+	size_t i;
+
+	for (i = 0; i < n; i++) {
+		if (dash2underscore(a[i]) != dash2underscore(b[i]))
+			return false;
+	}
+	return true;
+}
+
+bool parameq(const char *a, const char *b)
+{
+	return parameqn(a, b, strlen(a)+1);
+}
+
+static bool param_check_unsafe(const struct kernel_param *kp)
+{
+	if (kp->flags & KERNEL_PARAM_FL_HWPARAM &&
+	    security_locked_down(LOCKDOWN_MODULE_PARAMETERS))
+		return false;
+
+	if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
+		pr_notice("Setting dangerous option %s - tainting kernel\n",
+			  kp->name);
+		add_taint(TAINT_USER, LOCKDEP_STILL_OK);
+	}
+
+	return true;
+}
+
+static int parse_one(char *param,
+		     char *val,
+		     const char *doing,
+		     const struct kernel_param *params,
+		     unsigned num_params,
+		     s16 min_level,
+		     s16 max_level,
+		     void *arg,
+		     int (*handle_unknown)(char *param, char *val,
+				     const char *doing, void *arg))
+{
+	unsigned int i;
+	int err;
+
+	/* Find parameter */
+	for (i = 0; i < num_params; i++) {
+		if (parameq(param, params[i].name)) {
+			if (params[i].level < min_level
+			    || params[i].level > max_level)
+				return 0;
+			/* No one handled NULL, so do it here. */
+			if (!val &&
+			    !(params[i].ops->flags & KERNEL_PARAM_OPS_FL_NOARG))
+				return -EINVAL;
+			pr_debug("handling %s with %p\n", param,
+				params[i].ops->set);
+			kernel_param_lock(params[i].mod);
+			if (param_check_unsafe(&params[i]))
+				err = params[i].ops->set(val, &params[i]);
+			else
+				err = -EPERM;
+			kernel_param_unlock(params[i].mod);
+			return err;
+		}
+	}
+
+	if (handle_unknown) {
+		pr_debug("doing %s: %s='%s'\n", doing, param, val);
+		return handle_unknown(param, val, doing, arg);
+	}
+
+	pr_debug("Unknown argument '%s'\n", param);
+	return -ENOENT;
+}
+
+/* Args looks like "foo=bar,bar2 baz=fuz wiz". */
+char *parse_args(const char *doing,
+		 char *args,
+		 const struct kernel_param *params,
+		 unsigned num,
+		 s16 min_level,
+		 s16 max_level,
+		 void *arg,
+		 int (*unknown)(char *param, char *val,
+				const char *doing, void *arg))
+{
+	char *param, *val, *err = NULL;
+
+	/* Chew leading spaces */
+	args = skip_spaces(args);
+
+	if (*args)
+		pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
+
+	while (*args) {
+		int ret;
+		int irq_was_disabled;
+
+		args = next_arg(args, &param, &val);
+		/* Stop at -- */
+		if (!val && strcmp(param, "--") == 0)
+			return err ?: args;
+		irq_was_disabled = irqs_disabled();
+		ret = parse_one(param, val, doing, params, num,
+				min_level, max_level, arg, unknown);
+		if (irq_was_disabled && !irqs_disabled())
+			pr_warn("%s: option '%s' enabled irq's!\n",
+				doing, param);
+
+		switch (ret) {
+		case 0:
+			continue;
+		case -ENOENT:
+			pr_err("%s: Unknown parameter `%s'\n", doing, param);
+			break;
+		case -ENOSPC:
+			pr_err("%s: `%s' too large for parameter `%s'\n",
+			       doing, val ?: "", param);
+			break;
+		default:
+			pr_err("%s: `%s' invalid for parameter `%s'\n",
+			       doing, val ?: "", param);
+			break;
+		}
+
+		err = ERR_PTR(ret);
+	}
+
+	return err;
+}
+
+/* Lazy bastard, eh? */
+#define STANDARD_PARAM_DEF(name, type, format, strtolfn)      		\
+	int param_set_##name(const char *val, const struct kernel_param *kp) \
+	{								\
+		return strtolfn(val, 0, (type *)kp->arg);		\
+	}								\
+	int param_get_##name(char *buffer, const struct kernel_param *kp) \
+	{								\
+		return scnprintf(buffer, PAGE_SIZE, format "\n",	\
+				*((type *)kp->arg));			\
+	}								\
+	const struct kernel_param_ops param_ops_##name = {			\
+		.set = param_set_##name,				\
+		.get = param_get_##name,				\
+	};								\
+	EXPORT_SYMBOL(param_set_##name);				\
+	EXPORT_SYMBOL(param_get_##name);				\
+	EXPORT_SYMBOL(param_ops_##name)
+
+
+STANDARD_PARAM_DEF(byte,	unsigned char,		"%hhu",		kstrtou8);
+STANDARD_PARAM_DEF(short,	short,			"%hi",		kstrtos16);
+STANDARD_PARAM_DEF(ushort,	unsigned short,		"%hu",		kstrtou16);
+STANDARD_PARAM_DEF(int,		int,			"%i",		kstrtoint);
+STANDARD_PARAM_DEF(uint,	unsigned int,		"%u",		kstrtouint);
+STANDARD_PARAM_DEF(long,	long,			"%li",		kstrtol);
+STANDARD_PARAM_DEF(ulong,	unsigned long,		"%lu",		kstrtoul);
+STANDARD_PARAM_DEF(ullong,	unsigned long long,	"%llu",		kstrtoull);
+STANDARD_PARAM_DEF(hexint,	unsigned int,		"%#08x", 	kstrtouint);
+
+int param_set_uint_minmax(const char *val, const struct kernel_param *kp,
+		unsigned int min, unsigned int max)
+{
+	unsigned int num;
+	int ret;
+
+	if (!val)
+		return -EINVAL;
+	ret = kstrtouint(val, 0, &num);
+	if (ret)
+		return ret;
+	if (num < min || num > max)
+		return -EINVAL;
+	*((unsigned int *)kp->arg) = num;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(param_set_uint_minmax);
+
+int param_set_charp(const char *val, const struct kernel_param *kp)
+{
+	if (strlen(val) > 1024) {
+		pr_err("%s: string parameter too long\n", kp->name);
+		return -ENOSPC;
+	}
+
+	maybe_kfree_parameter(*(char **)kp->arg);
+
+	/* This is a hack.  We can't kmalloc in early boot, and we
+	 * don't need to; this mangled commandline is preserved. */
+	if (slab_is_available()) {
+		*(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
+		if (!*(char **)kp->arg)
+			return -ENOMEM;
+		strcpy(*(char **)kp->arg, val);
+	} else
+		*(const char **)kp->arg = val;
+
+	return 0;
+}
+EXPORT_SYMBOL(param_set_charp);
+
+int param_get_charp(char *buffer, const struct kernel_param *kp)
+{
+	return scnprintf(buffer, PAGE_SIZE, "%s\n", *((char **)kp->arg));
+}
+EXPORT_SYMBOL(param_get_charp);
+
+void param_free_charp(void *arg)
+{
+	maybe_kfree_parameter(*((char **)arg));
+}
+EXPORT_SYMBOL(param_free_charp);
+
+const struct kernel_param_ops param_ops_charp = {
+	.set = param_set_charp,
+	.get = param_get_charp,
+	.free = param_free_charp,
+};
+EXPORT_SYMBOL(param_ops_charp);
+
+/* Actually could be a bool or an int, for historical reasons. */
+int param_set_bool(const char *val, const struct kernel_param *kp)
+{
+	/* No equals means "set"... */
+	if (!val) val = "1";
+
+	/* One of =[yYnN01] */
+	return strtobool(val, kp->arg);
+}
+EXPORT_SYMBOL(param_set_bool);
+
+int param_get_bool(char *buffer, const struct kernel_param *kp)
+{
+	/* Y and N chosen as being relatively non-coder friendly */
+	return sprintf(buffer, "%c\n", *(bool *)kp->arg ? 'Y' : 'N');
+}
+EXPORT_SYMBOL(param_get_bool);
+
+const struct kernel_param_ops param_ops_bool = {
+	.flags = KERNEL_PARAM_OPS_FL_NOARG,
+	.set = param_set_bool,
+	.get = param_get_bool,
+};
+EXPORT_SYMBOL(param_ops_bool);
+
+int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
+{
+	int err = 0;
+	bool new_value;
+	bool orig_value = *(bool *)kp->arg;
+	struct kernel_param dummy_kp = *kp;
+
+	dummy_kp.arg = &new_value;
+
+	err = param_set_bool(val, &dummy_kp);
+	if (err)
+		return err;
+
+	/* Don't let them unset it once it's set! */
+	if (!new_value && orig_value)
+		return -EROFS;
+
+	if (new_value)
+		err = param_set_bool(val, kp);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
+
+const struct kernel_param_ops param_ops_bool_enable_only = {
+	.flags = KERNEL_PARAM_OPS_FL_NOARG,
+	.set = param_set_bool_enable_only,
+	.get = param_get_bool,
+};
+EXPORT_SYMBOL_GPL(param_ops_bool_enable_only);
+
+/* This one must be bool. */
+int param_set_invbool(const char *val, const struct kernel_param *kp)
+{
+	int ret;
+	bool boolval;
+	struct kernel_param dummy;
+
+	dummy.arg = &boolval;
+	ret = param_set_bool(val, &dummy);
+	if (ret == 0)
+		*(bool *)kp->arg = !boolval;
+	return ret;
+}
+EXPORT_SYMBOL(param_set_invbool);
+
+int param_get_invbool(char *buffer, const struct kernel_param *kp)
+{
+	return sprintf(buffer, "%c\n", (*(bool *)kp->arg) ? 'N' : 'Y');
+}
+EXPORT_SYMBOL(param_get_invbool);
+
+const struct kernel_param_ops param_ops_invbool = {
+	.set = param_set_invbool,
+	.get = param_get_invbool,
+};
+EXPORT_SYMBOL(param_ops_invbool);
+
+int param_set_bint(const char *val, const struct kernel_param *kp)
+{
+	/* Match bool exactly, by re-using it. */
+	struct kernel_param boolkp = *kp;
+	bool v;
+	int ret;
+
+	boolkp.arg = &v;
+
+	ret = param_set_bool(val, &boolkp);
+	if (ret == 0)
+		*(int *)kp->arg = v;
+	return ret;
+}
+EXPORT_SYMBOL(param_set_bint);
+
+const struct kernel_param_ops param_ops_bint = {
+	.flags = KERNEL_PARAM_OPS_FL_NOARG,
+	.set = param_set_bint,
+	.get = param_get_int,
+};
+EXPORT_SYMBOL(param_ops_bint);
+
+/* We break the rule and mangle the string. */
+static int param_array(struct module *mod,
+		       const char *name,
+		       const char *val,
+		       unsigned int min, unsigned int max,
+		       void *elem, int elemsize,
+		       int (*set)(const char *, const struct kernel_param *kp),
+		       s16 level,
+		       unsigned int *num)
+{
+	int ret;
+	struct kernel_param kp;
+	char save;
+
+	/* Get the name right for errors. */
+	kp.name = name;
+	kp.arg = elem;
+	kp.level = level;
+
+	*num = 0;
+	/* We expect a comma-separated list of values. */
+	do {
+		int len;
+
+		if (*num == max) {
+			pr_err("%s: can only take %i arguments\n", name, max);
+			return -EINVAL;
+		}
+		len = strcspn(val, ",");
+
+		/* nul-terminate and parse */
+		save = val[len];
+		((char *)val)[len] = '\0';
+		check_kparam_locked(mod);
+		ret = set(val, &kp);
+
+		if (ret != 0)
+			return ret;
+		kp.arg += elemsize;
+		val += len+1;
+		(*num)++;
+	} while (save == ',');
+
+	if (*num < min) {
+		pr_err("%s: needs at least %i arguments\n", name, min);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int param_array_set(const char *val, const struct kernel_param *kp)
+{
+	const struct kparam_array *arr = kp->arr;
+	unsigned int temp_num;
+
+	return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem,
+			   arr->elemsize, arr->ops->set, kp->level,
+			   arr->num ?: &temp_num);
+}
+
+static int param_array_get(char *buffer, const struct kernel_param *kp)
+{
+	int i, off, ret;
+	const struct kparam_array *arr = kp->arr;
+	struct kernel_param p = *kp;
+
+	for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
+		/* Replace \n with comma */
+		if (i)
+			buffer[off - 1] = ',';
+		p.arg = arr->elem + arr->elemsize * i;
+		check_kparam_locked(p.mod);
+		ret = arr->ops->get(buffer + off, &p);
+		if (ret < 0)
+			return ret;
+		off += ret;
+	}
+	buffer[off] = '\0';
+	return off;
+}
+
+static void param_array_free(void *arg)
+{
+	unsigned int i;
+	const struct kparam_array *arr = arg;
+
+	if (arr->ops->free)
+		for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
+			arr->ops->free(arr->elem + arr->elemsize * i);
+}
+
+const struct kernel_param_ops param_array_ops = {
+	.set = param_array_set,
+	.get = param_array_get,
+	.free = param_array_free,
+};
+EXPORT_SYMBOL(param_array_ops);
+
+int param_set_copystring(const char *val, const struct kernel_param *kp)
+{
+	const struct kparam_string *kps = kp->str;
+
+	if (strlen(val)+1 > kps->maxlen) {
+		pr_err("%s: string doesn't fit in %u chars.\n",
+		       kp->name, kps->maxlen-1);
+		return -ENOSPC;
+	}
+	strcpy(kps->string, val);
+	return 0;
+}
+EXPORT_SYMBOL(param_set_copystring);
+
+int param_get_string(char *buffer, const struct kernel_param *kp)
+{
+	const struct kparam_string *kps = kp->str;
+	return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string);
+}
+EXPORT_SYMBOL(param_get_string);
+
+const struct kernel_param_ops param_ops_string = {
+	.set = param_set_copystring,
+	.get = param_get_string,
+};
+EXPORT_SYMBOL(param_ops_string);
+
+/* sysfs output in /sys/modules/XYZ/parameters/ */
+#define to_module_attr(n) container_of(n, struct module_attribute, attr)
+#define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
+
+struct param_attribute
+{
+	struct module_attribute mattr;
+	const struct kernel_param *param;
+};
+
+struct module_param_attrs
+{
+	unsigned int num;
+	struct attribute_group grp;
+	struct param_attribute attrs[];
+};
+
+#ifdef CONFIG_SYSFS
+#define to_param_attr(n) container_of(n, struct param_attribute, mattr)
+
+static ssize_t param_attr_show(struct module_attribute *mattr,
+			       struct module_kobject *mk, char *buf)
+{
+	int count;
+	struct param_attribute *attribute = to_param_attr(mattr);
+
+	if (!attribute->param->ops->get)
+		return -EPERM;
+
+	kernel_param_lock(mk->mod);
+	count = attribute->param->ops->get(buf, attribute->param);
+	kernel_param_unlock(mk->mod);
+	return count;
+}
+
+/* sysfs always hands a nul-terminated string in buf.  We rely on that. */
+static ssize_t param_attr_store(struct module_attribute *mattr,
+				struct module_kobject *mk,
+				const char *buf, size_t len)
+{
+ 	int err;
+	struct param_attribute *attribute = to_param_attr(mattr);
+
+	if (!attribute->param->ops->set)
+		return -EPERM;
+
+	kernel_param_lock(mk->mod);
+	if (param_check_unsafe(attribute->param))
+		err = attribute->param->ops->set(buf, attribute->param);
+	else
+		err = -EPERM;
+	kernel_param_unlock(mk->mod);
+	if (!err)
+		return len;
+	return err;
+}
+#endif
+
+#ifdef CONFIG_MODULES
+#define __modinit
+#else
+#define __modinit __init
+#endif
+
+#ifdef CONFIG_SYSFS
+void kernel_param_lock(struct module *mod)
+{
+	mutex_lock(KPARAM_MUTEX(mod));
+}
+
+void kernel_param_unlock(struct module *mod)
+{
+	mutex_unlock(KPARAM_MUTEX(mod));
+}
+
+EXPORT_SYMBOL(kernel_param_lock);
+EXPORT_SYMBOL(kernel_param_unlock);
+
+/*
+ * add_sysfs_param - add a parameter to sysfs
+ * @mk: struct module_kobject
+ * @kp: the actual parameter definition to add to sysfs
+ * @name: name of parameter
+ *
+ * Create a kobject if for a (per-module) parameter if mp NULL, and
+ * create file in sysfs.  Returns an error on out of memory.  Always cleans up
+ * if there's an error.
+ */
+static __modinit int add_sysfs_param(struct module_kobject *mk,
+				     const struct kernel_param *kp,
+				     const char *name)
+{
+	struct module_param_attrs *new_mp;
+	struct attribute **new_attrs;
+	unsigned int i;
+
+	/* We don't bother calling this with invisible parameters. */
+	BUG_ON(!kp->perm);
+
+	if (!mk->mp) {
+		/* First allocation. */
+		mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
+		if (!mk->mp)
+			return -ENOMEM;
+		mk->mp->grp.name = "parameters";
+		/* NULL-terminated attribute array. */
+		mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
+					    GFP_KERNEL);
+		/* Caller will cleanup via free_module_param_attrs */
+		if (!mk->mp->grp.attrs)
+			return -ENOMEM;
+	}
+
+	/* Enlarge allocations. */
+	new_mp = krealloc(mk->mp,
+			  sizeof(*mk->mp) +
+			  sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
+			  GFP_KERNEL);
+	if (!new_mp)
+		return -ENOMEM;
+	mk->mp = new_mp;
+
+	/* Extra pointer for NULL terminator */
+	new_attrs = krealloc(mk->mp->grp.attrs,
+			     sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
+			     GFP_KERNEL);
+	if (!new_attrs)
+		return -ENOMEM;
+	mk->mp->grp.attrs = new_attrs;
+
+	/* Tack new one on the end. */
+	memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
+	sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
+	mk->mp->attrs[mk->mp->num].param = kp;
+	mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
+	/* Do not allow runtime DAC changes to make param writable. */
+	if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
+		mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
+	else
+		mk->mp->attrs[mk->mp->num].mattr.store = NULL;
+	mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
+	mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
+	mk->mp->num++;
+
+	/* Fix up all the pointers, since krealloc can move us */
+	for (i = 0; i < mk->mp->num; i++)
+		mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
+	mk->mp->grp.attrs[mk->mp->num] = NULL;
+	return 0;
+}
+
+#ifdef CONFIG_MODULES
+static void free_module_param_attrs(struct module_kobject *mk)
+{
+	if (mk->mp)
+		kfree(mk->mp->grp.attrs);
+	kfree(mk->mp);
+	mk->mp = NULL;
+}
+
+/*
+ * module_param_sysfs_setup - setup sysfs support for one module
+ * @mod: module
+ * @kparam: module parameters (array)
+ * @num_params: number of module parameters
+ *
+ * Adds sysfs entries for module parameters under
+ * /sys/module/[mod->name]/parameters/
+ */
+int module_param_sysfs_setup(struct module *mod,
+			     const struct kernel_param *kparam,
+			     unsigned int num_params)
+{
+	int i, err;
+	bool params = false;
+
+	for (i = 0; i < num_params; i++) {
+		if (kparam[i].perm == 0)
+			continue;
+		err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
+		if (err) {
+			free_module_param_attrs(&mod->mkobj);
+			return err;
+		}
+		params = true;
+	}
+
+	if (!params)
+		return 0;
+
+	/* Create the param group. */
+	err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
+	if (err)
+		free_module_param_attrs(&mod->mkobj);
+	return err;
+}
+
+/*
+ * module_param_sysfs_remove - remove sysfs support for one module
+ * @mod: module
+ *
+ * Remove sysfs entries for module parameters and the corresponding
+ * kobject.
+ */
+void module_param_sysfs_remove(struct module *mod)
+{
+	if (mod->mkobj.mp) {
+		sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
+		/* We are positive that no one is using any param
+		 * attrs at this point.  Deallocate immediately. */
+		free_module_param_attrs(&mod->mkobj);
+	}
+}
+#endif
+
+void destroy_params(const struct kernel_param *params, unsigned num)
+{
+	unsigned int i;
+
+	for (i = 0; i < num; i++)
+		if (params[i].ops->free)
+			params[i].ops->free(params[i].arg);
+}
+
+static struct module_kobject * __init locate_module_kobject(const char *name)
+{
+	struct module_kobject *mk;
+	struct kobject *kobj;
+	int err;
+
+	kobj = kset_find_obj(module_kset, name);
+	if (kobj) {
+		mk = to_module_kobject(kobj);
+	} else {
+		mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
+		BUG_ON(!mk);
+
+		mk->mod = THIS_MODULE;
+		mk->kobj.kset = module_kset;
+		err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
+					   "%s", name);
+#ifdef CONFIG_MODULES
+		if (!err)
+			err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
+#endif
+		if (err) {
+			kobject_put(&mk->kobj);
+			pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
+				name, err);
+			return NULL;
+		}
+
+		/* So that we hold reference in both cases. */
+		kobject_get(&mk->kobj);
+	}
+
+	return mk;
+}
+
+static void __init kernel_add_sysfs_param(const char *name,
+					  const struct kernel_param *kparam,
+					  unsigned int name_skip)
+{
+	struct module_kobject *mk;
+	int err;
+
+	mk = locate_module_kobject(name);
+	if (!mk)
+		return;
+
+	/* We need to remove old parameters before adding more. */
+	if (mk->mp)
+		sysfs_remove_group(&mk->kobj, &mk->mp->grp);
+
+	/* These should not fail at boot. */
+	err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
+	BUG_ON(err);
+	err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
+	BUG_ON(err);
+	kobject_uevent(&mk->kobj, KOBJ_ADD);
+	kobject_put(&mk->kobj);
+}
+
+/*
+ * param_sysfs_builtin - add sysfs parameters for built-in modules
+ *
+ * Add module_parameters to sysfs for "modules" built into the kernel.
+ *
+ * The "module" name (KBUILD_MODNAME) is stored before a dot, the
+ * "parameter" name is stored behind a dot in kernel_param->name. So,
+ * extract the "module" name for all built-in kernel_param-eters,
+ * and for all who have the same, call kernel_add_sysfs_param.
+ */
+static void __init param_sysfs_builtin(void)
+{
+	const struct kernel_param *kp;
+	unsigned int name_len;
+	char modname[MODULE_NAME_LEN];
+
+	for (kp = __start___param; kp < __stop___param; kp++) {
+		char *dot;
+
+		if (kp->perm == 0)
+			continue;
+
+		dot = strchr(kp->name, '.');
+		if (!dot) {
+			/* This happens for core_param() */
+			strcpy(modname, "kernel");
+			name_len = 0;
+		} else {
+			name_len = dot - kp->name + 1;
+			strlcpy(modname, kp->name, name_len);
+		}
+		kernel_add_sysfs_param(modname, kp, name_len);
+	}
+}
+
+ssize_t __modver_version_show(struct module_attribute *mattr,
+			      struct module_kobject *mk, char *buf)
+{
+	struct module_version_attribute *vattr =
+		container_of(mattr, struct module_version_attribute, mattr);
+
+	return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
+}
+
+extern const struct module_version_attribute __start___modver[];
+extern const struct module_version_attribute __stop___modver[];
+
+static void __init version_sysfs_builtin(void)
+{
+	const struct module_version_attribute *vattr;
+	struct module_kobject *mk;
+	int err;
+
+	for (vattr = __start___modver; vattr < __stop___modver; vattr++) {
+		mk = locate_module_kobject(vattr->module_name);
+		if (mk) {
+			err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
+			WARN_ON_ONCE(err);
+			kobject_uevent(&mk->kobj, KOBJ_ADD);
+			kobject_put(&mk->kobj);
+		}
+	}
+}
+
+/* module-related sysfs stuff */
+
+static ssize_t module_attr_show(struct kobject *kobj,
+				struct attribute *attr,
+				char *buf)
+{
+	struct module_attribute *attribute;
+	struct module_kobject *mk;
+	int ret;
+
+	attribute = to_module_attr(attr);
+	mk = to_module_kobject(kobj);
+
+	if (!attribute->show)
+		return -EIO;
+
+	ret = attribute->show(attribute, mk, buf);
+
+	return ret;
+}
+
+static ssize_t module_attr_store(struct kobject *kobj,
+				struct attribute *attr,
+				const char *buf, size_t len)
+{
+	struct module_attribute *attribute;
+	struct module_kobject *mk;
+	int ret;
+
+	attribute = to_module_attr(attr);
+	mk = to_module_kobject(kobj);
+
+	if (!attribute->store)
+		return -EIO;
+
+	ret = attribute->store(attribute, mk, buf, len);
+
+	return ret;
+}
+
+static const struct sysfs_ops module_sysfs_ops = {
+	.show = module_attr_show,
+	.store = module_attr_store,
+};
+
+static int uevent_filter(struct kobject *kobj)
+{
+	const struct kobj_type *ktype = get_ktype(kobj);
+
+	if (ktype == &module_ktype)
+		return 1;
+	return 0;
+}
+
+static const struct kset_uevent_ops module_uevent_ops = {
+	.filter = uevent_filter,
+};
+
+struct kset *module_kset;
+int module_sysfs_initialized;
+
+static void module_kobj_release(struct kobject *kobj)
+{
+	struct module_kobject *mk = to_module_kobject(kobj);
+	complete(mk->kobj_completion);
+}
+
+struct kobj_type module_ktype = {
+	.release   =	module_kobj_release,
+	.sysfs_ops =	&module_sysfs_ops,
+};
+
+/*
+ * param_sysfs_init - wrapper for built-in params support
+ */
+static int __init param_sysfs_init(void)
+{
+	module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
+	if (!module_kset) {
+		printk(KERN_WARNING "%s (%d): error creating kset\n",
+			__FILE__, __LINE__);
+		return -ENOMEM;
+	}
+	module_sysfs_initialized = 1;
+
+	version_sysfs_builtin();
+	param_sysfs_builtin();
+
+	return 0;
+}
+subsys_initcall(param_sysfs_init);
+
+#endif /* CONFIG_SYSFS */
diff --git a/kernel/pid.c b/kernel/pid.c
new file mode 100644
index 000000000..3fbc5e46b
--- /dev/null
+++ b/kernel/pid.c
@@ -0,0 +1,747 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic pidhash and scalable, time-bounded PID allocator
+ *
+ * (C) 2002-2003 Nadia Yvette Chambers, IBM
+ * (C) 2004 Nadia Yvette Chambers, Oracle
+ * (C) 2002-2004 Ingo Molnar, Red Hat
+ *
+ * pid-structures are backing objects for tasks sharing a given ID to chain
+ * against. There is very little to them aside from hashing them and
+ * parking tasks using given ID's on a list.
+ *
+ * The hash is always changed with the tasklist_lock write-acquired,
+ * and the hash is only accessed with the tasklist_lock at least
+ * read-acquired, so there's no additional SMP locking needed here.
+ *
+ * We have a list of bitmap pages, which bitmaps represent the PID space.
+ * Allocating and freeing PIDs is completely lockless. The worst-case
+ * allocation scenario when all but one out of 1 million PIDs possible are
+ * allocated already: the scanning of 32 list entries and at most PAGE_SIZE
+ * bytes. The typical fastpath is a single successful setbit. Freeing is O(1).
+ *
+ * Pid namespaces:
+ *    (C) 2007 Pavel Emelyanov <xemul@openvz.org>, OpenVZ, SWsoft Inc.
+ *    (C) 2007 Sukadev Bhattiprolu <sukadev@us.ibm.com>, IBM
+ *     Many thanks to Oleg Nesterov for comments and help
+ *
+ */
+
+#include <linux/mm.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/rculist.h>
+#include <linux/memblock.h>
+#include <linux/pid_namespace.h>
+#include <linux/init_task.h>
+#include <linux/syscalls.h>
+#include <linux/proc_ns.h>
+#include <linux/refcount.h>
+#include <linux/anon_inodes.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/task.h>
+#include <linux/idr.h>
+#include <net/sock.h>
+#include <uapi/linux/pidfd.h>
+
+struct pid init_struct_pid = {
+	.count		= REFCOUNT_INIT(1),
+	.tasks		= {
+		{ .first = NULL },
+		{ .first = NULL },
+		{ .first = NULL },
+	},
+	.level		= 0,
+	.numbers	= { {
+		.nr		= 0,
+		.ns		= &init_pid_ns,
+	}, }
+};
+
+int pid_max = PID_MAX_DEFAULT;
+
+#define RESERVED_PIDS		300
+
+int pid_max_min = RESERVED_PIDS + 1;
+int pid_max_max = PID_MAX_LIMIT;
+
+/*
+ * PID-map pages start out as NULL, they get allocated upon
+ * first use and are never deallocated. This way a low pid_max
+ * value does not cause lots of bitmaps to be allocated, but
+ * the scheme scales to up to 4 million PIDs, runtime.
+ */
+struct pid_namespace init_pid_ns = {
+	.ns.count = REFCOUNT_INIT(2),
+	.idr = IDR_INIT(init_pid_ns.idr),
+	.pid_allocated = PIDNS_ADDING,
+	.level = 0,
+	.child_reaper = &init_task,
+	.user_ns = &init_user_ns,
+	.ns.inum = PROC_PID_INIT_INO,
+#ifdef CONFIG_PID_NS
+	.ns.ops = &pidns_operations,
+#endif
+};
+EXPORT_SYMBOL_GPL(init_pid_ns);
+
+/*
+ * Note: disable interrupts while the pidmap_lock is held as an
+ * interrupt might come in and do read_lock(&tasklist_lock).
+ *
+ * If we don't disable interrupts there is a nasty deadlock between
+ * detach_pid()->free_pid() and another cpu that does
+ * spin_lock(&pidmap_lock) followed by an interrupt routine that does
+ * read_lock(&tasklist_lock);
+ *
+ * After we clean up the tasklist_lock and know there are no
+ * irq handlers that take it we can leave the interrupts enabled.
+ * For now it is easier to be safe than to prove it can't happen.
+ */
+
+static  __cacheline_aligned_in_smp DEFINE_SPINLOCK(pidmap_lock);
+
+void put_pid(struct pid *pid)
+{
+	struct pid_namespace *ns;
+
+	if (!pid)
+		return;
+
+	ns = pid->numbers[pid->level].ns;
+	if (refcount_dec_and_test(&pid->count)) {
+		kmem_cache_free(ns->pid_cachep, pid);
+		put_pid_ns(ns);
+	}
+}
+EXPORT_SYMBOL_GPL(put_pid);
+
+static void delayed_put_pid(struct rcu_head *rhp)
+{
+	struct pid *pid = container_of(rhp, struct pid, rcu);
+	put_pid(pid);
+}
+
+void free_pid(struct pid *pid)
+{
+	/* We can be called with write_lock_irq(&tasklist_lock) held */
+	int i;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pidmap_lock, flags);
+	for (i = 0; i <= pid->level; i++) {
+		struct upid *upid = pid->numbers + i;
+		struct pid_namespace *ns = upid->ns;
+		switch (--ns->pid_allocated) {
+		case 2:
+		case 1:
+			/* When all that is left in the pid namespace
+			 * is the reaper wake up the reaper.  The reaper
+			 * may be sleeping in zap_pid_ns_processes().
+			 */
+			wake_up_process(ns->child_reaper);
+			break;
+		case PIDNS_ADDING:
+			/* Handle a fork failure of the first process */
+			WARN_ON(ns->child_reaper);
+			ns->pid_allocated = 0;
+			break;
+		}
+
+		idr_remove(&ns->idr, upid->nr);
+	}
+	spin_unlock_irqrestore(&pidmap_lock, flags);
+
+	call_rcu(&pid->rcu, delayed_put_pid);
+}
+
+struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid,
+		      size_t set_tid_size)
+{
+	struct pid *pid;
+	enum pid_type type;
+	int i, nr;
+	struct pid_namespace *tmp;
+	struct upid *upid;
+	int retval = -ENOMEM;
+
+	/*
+	 * set_tid_size contains the size of the set_tid array. Starting at
+	 * the most nested currently active PID namespace it tells alloc_pid()
+	 * which PID to set for a process in that most nested PID namespace
+	 * up to set_tid_size PID namespaces. It does not have to set the PID
+	 * for a process in all nested PID namespaces but set_tid_size must
+	 * never be greater than the current ns->level + 1.
+	 */
+	if (set_tid_size > ns->level + 1)
+		return ERR_PTR(-EINVAL);
+
+	pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL);
+	if (!pid)
+		return ERR_PTR(retval);
+
+	tmp = ns;
+	pid->level = ns->level;
+
+	for (i = ns->level; i >= 0; i--) {
+		int tid = 0;
+
+		if (set_tid_size) {
+			tid = set_tid[ns->level - i];
+
+			retval = -EINVAL;
+			if (tid < 1 || tid >= pid_max)
+				goto out_free;
+			/*
+			 * Also fail if a PID != 1 is requested and
+			 * no PID 1 exists.
+			 */
+			if (tid != 1 && !tmp->child_reaper)
+				goto out_free;
+			retval = -EPERM;
+			if (!checkpoint_restore_ns_capable(tmp->user_ns))
+				goto out_free;
+			set_tid_size--;
+		}
+
+		idr_preload(GFP_KERNEL);
+		spin_lock_irq(&pidmap_lock);
+
+		if (tid) {
+			nr = idr_alloc(&tmp->idr, NULL, tid,
+				       tid + 1, GFP_ATOMIC);
+			/*
+			 * If ENOSPC is returned it means that the PID is
+			 * alreay in use. Return EEXIST in that case.
+			 */
+			if (nr == -ENOSPC)
+				nr = -EEXIST;
+		} else {
+			int pid_min = 1;
+			/*
+			 * init really needs pid 1, but after reaching the
+			 * maximum wrap back to RESERVED_PIDS
+			 */
+			if (idr_get_cursor(&tmp->idr) > RESERVED_PIDS)
+				pid_min = RESERVED_PIDS;
+
+			/*
+			 * Store a null pointer so find_pid_ns does not find
+			 * a partially initialized PID (see below).
+			 */
+			nr = idr_alloc_cyclic(&tmp->idr, NULL, pid_min,
+					      pid_max, GFP_ATOMIC);
+		}
+		spin_unlock_irq(&pidmap_lock);
+		idr_preload_end();
+
+		if (nr < 0) {
+			retval = (nr == -ENOSPC) ? -EAGAIN : nr;
+			goto out_free;
+		}
+
+		pid->numbers[i].nr = nr;
+		pid->numbers[i].ns = tmp;
+		tmp = tmp->parent;
+	}
+
+	/*
+	 * ENOMEM is not the most obvious choice especially for the case
+	 * where the child subreaper has already exited and the pid
+	 * namespace denies the creation of any new processes. But ENOMEM
+	 * is what we have exposed to userspace for a long time and it is
+	 * documented behavior for pid namespaces. So we can't easily
+	 * change it even if there were an error code better suited.
+	 */
+	retval = -ENOMEM;
+
+	get_pid_ns(ns);
+	refcount_set(&pid->count, 1);
+	spin_lock_init(&pid->lock);
+	for (type = 0; type < PIDTYPE_MAX; ++type)
+		INIT_HLIST_HEAD(&pid->tasks[type]);
+
+	init_waitqueue_head(&pid->wait_pidfd);
+	INIT_HLIST_HEAD(&pid->inodes);
+
+	upid = pid->numbers + ns->level;
+	spin_lock_irq(&pidmap_lock);
+	if (!(ns->pid_allocated & PIDNS_ADDING))
+		goto out_unlock;
+	for ( ; upid >= pid->numbers; --upid) {
+		/* Make the PID visible to find_pid_ns. */
+		idr_replace(&upid->ns->idr, pid, upid->nr);
+		upid->ns->pid_allocated++;
+	}
+	spin_unlock_irq(&pidmap_lock);
+
+	return pid;
+
+out_unlock:
+	spin_unlock_irq(&pidmap_lock);
+	put_pid_ns(ns);
+
+out_free:
+	spin_lock_irq(&pidmap_lock);
+	while (++i <= ns->level) {
+		upid = pid->numbers + i;
+		idr_remove(&upid->ns->idr, upid->nr);
+	}
+
+	/* On failure to allocate the first pid, reset the state */
+	if (ns->pid_allocated == PIDNS_ADDING)
+		idr_set_cursor(&ns->idr, 0);
+
+	spin_unlock_irq(&pidmap_lock);
+
+	kmem_cache_free(ns->pid_cachep, pid);
+	return ERR_PTR(retval);
+}
+
+void disable_pid_allocation(struct pid_namespace *ns)
+{
+	spin_lock_irq(&pidmap_lock);
+	ns->pid_allocated &= ~PIDNS_ADDING;
+	spin_unlock_irq(&pidmap_lock);
+}
+
+struct pid *find_pid_ns(int nr, struct pid_namespace *ns)
+{
+	return idr_find(&ns->idr, nr);
+}
+EXPORT_SYMBOL_GPL(find_pid_ns);
+
+struct pid *find_vpid(int nr)
+{
+	return find_pid_ns(nr, task_active_pid_ns(current));
+}
+EXPORT_SYMBOL_GPL(find_vpid);
+
+static struct pid **task_pid_ptr(struct task_struct *task, enum pid_type type)
+{
+	return (type == PIDTYPE_PID) ?
+		&task->thread_pid :
+		&task->signal->pids[type];
+}
+
+/*
+ * attach_pid() must be called with the tasklist_lock write-held.
+ */
+void attach_pid(struct task_struct *task, enum pid_type type)
+{
+	struct pid *pid = *task_pid_ptr(task, type);
+	hlist_add_head_rcu(&task->pid_links[type], &pid->tasks[type]);
+}
+
+static void __change_pid(struct task_struct *task, enum pid_type type,
+			struct pid *new)
+{
+	struct pid **pid_ptr = task_pid_ptr(task, type);
+	struct pid *pid;
+	int tmp;
+
+	pid = *pid_ptr;
+
+	hlist_del_rcu(&task->pid_links[type]);
+	*pid_ptr = new;
+
+	for (tmp = PIDTYPE_MAX; --tmp >= 0; )
+		if (pid_has_task(pid, tmp))
+			return;
+
+	free_pid(pid);
+}
+
+void detach_pid(struct task_struct *task, enum pid_type type)
+{
+	__change_pid(task, type, NULL);
+}
+
+void change_pid(struct task_struct *task, enum pid_type type,
+		struct pid *pid)
+{
+	__change_pid(task, type, pid);
+	attach_pid(task, type);
+}
+
+void exchange_tids(struct task_struct *left, struct task_struct *right)
+{
+	struct pid *pid1 = left->thread_pid;
+	struct pid *pid2 = right->thread_pid;
+	struct hlist_head *head1 = &pid1->tasks[PIDTYPE_PID];
+	struct hlist_head *head2 = &pid2->tasks[PIDTYPE_PID];
+
+	/* Swap the single entry tid lists */
+	hlists_swap_heads_rcu(head1, head2);
+
+	/* Swap the per task_struct pid */
+	rcu_assign_pointer(left->thread_pid, pid2);
+	rcu_assign_pointer(right->thread_pid, pid1);
+
+	/* Swap the cached value */
+	WRITE_ONCE(left->pid, pid_nr(pid2));
+	WRITE_ONCE(right->pid, pid_nr(pid1));
+}
+
+/* transfer_pid is an optimization of attach_pid(new), detach_pid(old) */
+void transfer_pid(struct task_struct *old, struct task_struct *new,
+			   enum pid_type type)
+{
+	if (type == PIDTYPE_PID)
+		new->thread_pid = old->thread_pid;
+	hlist_replace_rcu(&old->pid_links[type], &new->pid_links[type]);
+}
+
+struct task_struct *pid_task(struct pid *pid, enum pid_type type)
+{
+	struct task_struct *result = NULL;
+	if (pid) {
+		struct hlist_node *first;
+		first = rcu_dereference_check(hlist_first_rcu(&pid->tasks[type]),
+					      lockdep_tasklist_lock_is_held());
+		if (first)
+			result = hlist_entry(first, struct task_struct, pid_links[(type)]);
+	}
+	return result;
+}
+EXPORT_SYMBOL(pid_task);
+
+/*
+ * Must be called under rcu_read_lock().
+ */
+struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns)
+{
+	RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
+			 "find_task_by_pid_ns() needs rcu_read_lock() protection");
+	return pid_task(find_pid_ns(nr, ns), PIDTYPE_PID);
+}
+
+struct task_struct *find_task_by_vpid(pid_t vnr)
+{
+	return find_task_by_pid_ns(vnr, task_active_pid_ns(current));
+}
+
+struct task_struct *find_get_task_by_vpid(pid_t nr)
+{
+	struct task_struct *task;
+
+	rcu_read_lock();
+	task = find_task_by_vpid(nr);
+	if (task)
+		get_task_struct(task);
+	rcu_read_unlock();
+
+	return task;
+}
+
+struct pid *get_task_pid(struct task_struct *task, enum pid_type type)
+{
+	struct pid *pid;
+	rcu_read_lock();
+	pid = get_pid(rcu_dereference(*task_pid_ptr(task, type)));
+	rcu_read_unlock();
+	return pid;
+}
+EXPORT_SYMBOL_GPL(get_task_pid);
+
+struct task_struct *get_pid_task(struct pid *pid, enum pid_type type)
+{
+	struct task_struct *result;
+	rcu_read_lock();
+	result = pid_task(pid, type);
+	if (result)
+		get_task_struct(result);
+	rcu_read_unlock();
+	return result;
+}
+EXPORT_SYMBOL_GPL(get_pid_task);
+
+struct pid *find_get_pid(pid_t nr)
+{
+	struct pid *pid;
+
+	rcu_read_lock();
+	pid = get_pid(find_vpid(nr));
+	rcu_read_unlock();
+
+	return pid;
+}
+EXPORT_SYMBOL_GPL(find_get_pid);
+
+pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns)
+{
+	struct upid *upid;
+	pid_t nr = 0;
+
+	if (pid && ns->level <= pid->level) {
+		upid = &pid->numbers[ns->level];
+		if (upid->ns == ns)
+			nr = upid->nr;
+	}
+	return nr;
+}
+EXPORT_SYMBOL_GPL(pid_nr_ns);
+
+pid_t pid_vnr(struct pid *pid)
+{
+	return pid_nr_ns(pid, task_active_pid_ns(current));
+}
+EXPORT_SYMBOL_GPL(pid_vnr);
+
+pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
+			struct pid_namespace *ns)
+{
+	pid_t nr = 0;
+
+	rcu_read_lock();
+	if (!ns)
+		ns = task_active_pid_ns(current);
+	nr = pid_nr_ns(rcu_dereference(*task_pid_ptr(task, type)), ns);
+	rcu_read_unlock();
+
+	return nr;
+}
+EXPORT_SYMBOL(__task_pid_nr_ns);
+
+struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
+{
+	return ns_of_pid(task_pid(tsk));
+}
+EXPORT_SYMBOL_GPL(task_active_pid_ns);
+
+/*
+ * Used by proc to find the first pid that is greater than or equal to nr.
+ *
+ * If there is a pid at nr this function is exactly the same as find_pid_ns.
+ */
+struct pid *find_ge_pid(int nr, struct pid_namespace *ns)
+{
+	return idr_get_next(&ns->idr, &nr);
+}
+EXPORT_SYMBOL_GPL(find_ge_pid);
+
+struct pid *pidfd_get_pid(unsigned int fd, unsigned int *flags)
+{
+	struct fd f;
+	struct pid *pid;
+
+	f = fdget(fd);
+	if (!f.file)
+		return ERR_PTR(-EBADF);
+
+	pid = pidfd_pid(f.file);
+	if (!IS_ERR(pid)) {
+		get_pid(pid);
+		*flags = f.file->f_flags;
+	}
+
+	fdput(f);
+	return pid;
+}
+
+/**
+ * pidfd_get_task() - Get the task associated with a pidfd
+ *
+ * @pidfd: pidfd for which to get the task
+ * @flags: flags associated with this pidfd
+ *
+ * Return the task associated with @pidfd. The function takes a reference on
+ * the returned task. The caller is responsible for releasing that reference.
+ *
+ * Currently, the process identified by @pidfd is always a thread-group leader.
+ * This restriction currently exists for all aspects of pidfds including pidfd
+ * creation (CLONE_PIDFD cannot be used with CLONE_THREAD) and pidfd polling
+ * (only supports thread group leaders).
+ *
+ * Return: On success, the task_struct associated with the pidfd.
+ *	   On error, a negative errno number will be returned.
+ */
+struct task_struct *pidfd_get_task(int pidfd, unsigned int *flags)
+{
+	unsigned int f_flags;
+	struct pid *pid;
+	struct task_struct *task;
+
+	pid = pidfd_get_pid(pidfd, &f_flags);
+	if (IS_ERR(pid))
+		return ERR_CAST(pid);
+
+	task = get_pid_task(pid, PIDTYPE_TGID);
+	put_pid(pid);
+	if (!task)
+		return ERR_PTR(-ESRCH);
+
+	*flags = f_flags;
+	return task;
+}
+
+/**
+ * pidfd_create() - Create a new pid file descriptor.
+ *
+ * @pid:   struct pid that the pidfd will reference
+ * @flags: flags to pass
+ *
+ * This creates a new pid file descriptor with the O_CLOEXEC flag set.
+ *
+ * Note, that this function can only be called after the fd table has
+ * been unshared to avoid leaking the pidfd to the new process.
+ *
+ * This symbol should not be explicitly exported to loadable modules.
+ *
+ * Return: On success, a cloexec pidfd is returned.
+ *         On error, a negative errno number will be returned.
+ */
+int pidfd_create(struct pid *pid, unsigned int flags)
+{
+	int fd;
+
+	if (!pid || !pid_has_task(pid, PIDTYPE_TGID))
+		return -EINVAL;
+
+	if (flags & ~(O_NONBLOCK | O_RDWR | O_CLOEXEC))
+		return -EINVAL;
+
+	fd = anon_inode_getfd("[pidfd]", &pidfd_fops, get_pid(pid),
+			      flags | O_RDWR | O_CLOEXEC);
+	if (fd < 0)
+		put_pid(pid);
+
+	return fd;
+}
+
+/**
+ * pidfd_open() - Open new pid file descriptor.
+ *
+ * @pid:   pid for which to retrieve a pidfd
+ * @flags: flags to pass
+ *
+ * This creates a new pid file descriptor with the O_CLOEXEC flag set for
+ * the process identified by @pid. Currently, the process identified by
+ * @pid must be a thread-group leader. This restriction currently exists
+ * for all aspects of pidfds including pidfd creation (CLONE_PIDFD cannot
+ * be used with CLONE_THREAD) and pidfd polling (only supports thread group
+ * leaders).
+ *
+ * Return: On success, a cloexec pidfd is returned.
+ *         On error, a negative errno number will be returned.
+ */
+SYSCALL_DEFINE2(pidfd_open, pid_t, pid, unsigned int, flags)
+{
+	int fd;
+	struct pid *p;
+
+	if (flags & ~PIDFD_NONBLOCK)
+		return -EINVAL;
+
+	if (pid <= 0)
+		return -EINVAL;
+
+	p = find_get_pid(pid);
+	if (!p)
+		return -ESRCH;
+
+	fd = pidfd_create(p, flags);
+
+	put_pid(p);
+	return fd;
+}
+
+void __init pid_idr_init(void)
+{
+	/* Verify no one has done anything silly: */
+	BUILD_BUG_ON(PID_MAX_LIMIT >= PIDNS_ADDING);
+
+	/* bump default and minimum pid_max based on number of cpus */
+	pid_max = min(pid_max_max, max_t(int, pid_max,
+				PIDS_PER_CPU_DEFAULT * num_possible_cpus()));
+	pid_max_min = max_t(int, pid_max_min,
+				PIDS_PER_CPU_MIN * num_possible_cpus());
+	pr_info("pid_max: default: %u minimum: %u\n", pid_max, pid_max_min);
+
+	idr_init(&init_pid_ns.idr);
+
+	init_pid_ns.pid_cachep = KMEM_CACHE(pid,
+			SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT);
+}
+
+static struct file *__pidfd_fget(struct task_struct *task, int fd)
+{
+	struct file *file;
+	int ret;
+
+	ret = down_read_killable(&task->signal->exec_update_lock);
+	if (ret)
+		return ERR_PTR(ret);
+
+	if (ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS))
+		file = fget_task(task, fd);
+	else
+		file = ERR_PTR(-EPERM);
+
+	up_read(&task->signal->exec_update_lock);
+
+	return file ?: ERR_PTR(-EBADF);
+}
+
+static int pidfd_getfd(struct pid *pid, int fd)
+{
+	struct task_struct *task;
+	struct file *file;
+	int ret;
+
+	task = get_pid_task(pid, PIDTYPE_PID);
+	if (!task)
+		return -ESRCH;
+
+	file = __pidfd_fget(task, fd);
+	put_task_struct(task);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
+	ret = receive_fd(file, O_CLOEXEC);
+	fput(file);
+
+	return ret;
+}
+
+/**
+ * sys_pidfd_getfd() - Get a file descriptor from another process
+ *
+ * @pidfd:	the pidfd file descriptor of the process
+ * @fd:		the file descriptor number to get
+ * @flags:	flags on how to get the fd (reserved)
+ *
+ * This syscall gets a copy of a file descriptor from another process
+ * based on the pidfd, and file descriptor number. It requires that
+ * the calling process has the ability to ptrace the process represented
+ * by the pidfd. The process which is having its file descriptor copied
+ * is otherwise unaffected.
+ *
+ * Return: On success, a cloexec file descriptor is returned.
+ *         On error, a negative errno number will be returned.
+ */
+SYSCALL_DEFINE3(pidfd_getfd, int, pidfd, int, fd,
+		unsigned int, flags)
+{
+	struct pid *pid;
+	struct fd f;
+	int ret;
+
+	/* flags is currently unused - make sure it's unset */
+	if (flags)
+		return -EINVAL;
+
+	f = fdget(pidfd);
+	if (!f.file)
+		return -EBADF;
+
+	pid = pidfd_pid(f.file);
+	if (IS_ERR(pid))
+		ret = PTR_ERR(pid);
+	else
+		ret = pidfd_getfd(pid, fd);
+
+	fdput(f);
+	return ret;
+}
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
new file mode 100644
index 000000000..fc21c5d5f
--- /dev/null
+++ b/kernel/pid_namespace.c
@@ -0,0 +1,478 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Pid namespaces
+ *
+ * Authors:
+ *    (C) 2007 Pavel Emelyanov <xemul@openvz.org>, OpenVZ, SWsoft Inc.
+ *    (C) 2007 Sukadev Bhattiprolu <sukadev@us.ibm.com>, IBM
+ *     Many thanks to Oleg Nesterov for comments and help
+ *
+ */
+
+#include <linux/pid.h>
+#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
+#include <linux/syscalls.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <linux/acct.h>
+#include <linux/slab.h>
+#include <linux/proc_ns.h>
+#include <linux/reboot.h>
+#include <linux/export.h>
+#include <linux/sched/task.h>
+#include <linux/sched/signal.h>
+#include <linux/idr.h>
+
+static DEFINE_MUTEX(pid_caches_mutex);
+static struct kmem_cache *pid_ns_cachep;
+/* Write once array, filled from the beginning. */
+static struct kmem_cache *pid_cache[MAX_PID_NS_LEVEL];
+
+/*
+ * creates the kmem cache to allocate pids from.
+ * @level: pid namespace level
+ */
+
+static struct kmem_cache *create_pid_cachep(unsigned int level)
+{
+	/* Level 0 is init_pid_ns.pid_cachep */
+	struct kmem_cache **pkc = &pid_cache[level - 1];
+	struct kmem_cache *kc;
+	char name[4 + 10 + 1];
+	unsigned int len;
+
+	kc = READ_ONCE(*pkc);
+	if (kc)
+		return kc;
+
+	snprintf(name, sizeof(name), "pid_%u", level + 1);
+	len = sizeof(struct pid) + level * sizeof(struct upid);
+	mutex_lock(&pid_caches_mutex);
+	/* Name collision forces to do allocation under mutex. */
+	if (!*pkc)
+		*pkc = kmem_cache_create(name, len, 0,
+					 SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT, NULL);
+	mutex_unlock(&pid_caches_mutex);
+	/* current can fail, but someone else can succeed. */
+	return READ_ONCE(*pkc);
+}
+
+static struct ucounts *inc_pid_namespaces(struct user_namespace *ns)
+{
+	return inc_ucount(ns, current_euid(), UCOUNT_PID_NAMESPACES);
+}
+
+static void dec_pid_namespaces(struct ucounts *ucounts)
+{
+	dec_ucount(ucounts, UCOUNT_PID_NAMESPACES);
+}
+
+static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns,
+	struct pid_namespace *parent_pid_ns)
+{
+	struct pid_namespace *ns;
+	unsigned int level = parent_pid_ns->level + 1;
+	struct ucounts *ucounts;
+	int err;
+
+	err = -EINVAL;
+	if (!in_userns(parent_pid_ns->user_ns, user_ns))
+		goto out;
+
+	err = -ENOSPC;
+	if (level > MAX_PID_NS_LEVEL)
+		goto out;
+	ucounts = inc_pid_namespaces(user_ns);
+	if (!ucounts)
+		goto out;
+
+	err = -ENOMEM;
+	ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL);
+	if (ns == NULL)
+		goto out_dec;
+
+	idr_init(&ns->idr);
+
+	ns->pid_cachep = create_pid_cachep(level);
+	if (ns->pid_cachep == NULL)
+		goto out_free_idr;
+
+	err = ns_alloc_inum(&ns->ns);
+	if (err)
+		goto out_free_idr;
+	ns->ns.ops = &pidns_operations;
+
+	refcount_set(&ns->ns.count, 1);
+	ns->level = level;
+	ns->parent = get_pid_ns(parent_pid_ns);
+	ns->user_ns = get_user_ns(user_ns);
+	ns->ucounts = ucounts;
+	ns->pid_allocated = PIDNS_ADDING;
+
+	return ns;
+
+out_free_idr:
+	idr_destroy(&ns->idr);
+	kmem_cache_free(pid_ns_cachep, ns);
+out_dec:
+	dec_pid_namespaces(ucounts);
+out:
+	return ERR_PTR(err);
+}
+
+static void delayed_free_pidns(struct rcu_head *p)
+{
+	struct pid_namespace *ns = container_of(p, struct pid_namespace, rcu);
+
+	dec_pid_namespaces(ns->ucounts);
+	put_user_ns(ns->user_ns);
+
+	kmem_cache_free(pid_ns_cachep, ns);
+}
+
+static void destroy_pid_namespace(struct pid_namespace *ns)
+{
+	ns_free_inum(&ns->ns);
+
+	idr_destroy(&ns->idr);
+	call_rcu(&ns->rcu, delayed_free_pidns);
+}
+
+struct pid_namespace *copy_pid_ns(unsigned long flags,
+	struct user_namespace *user_ns, struct pid_namespace *old_ns)
+{
+	if (!(flags & CLONE_NEWPID))
+		return get_pid_ns(old_ns);
+	if (task_active_pid_ns(current) != old_ns)
+		return ERR_PTR(-EINVAL);
+	return create_pid_namespace(user_ns, old_ns);
+}
+
+void put_pid_ns(struct pid_namespace *ns)
+{
+	struct pid_namespace *parent;
+
+	while (ns != &init_pid_ns) {
+		parent = ns->parent;
+		if (!refcount_dec_and_test(&ns->ns.count))
+			break;
+		destroy_pid_namespace(ns);
+		ns = parent;
+	}
+}
+EXPORT_SYMBOL_GPL(put_pid_ns);
+
+void zap_pid_ns_processes(struct pid_namespace *pid_ns)
+{
+	int nr;
+	int rc;
+	struct task_struct *task, *me = current;
+	int init_pids = thread_group_leader(me) ? 1 : 2;
+	struct pid *pid;
+
+	/* Don't allow any more processes into the pid namespace */
+	disable_pid_allocation(pid_ns);
+
+	/*
+	 * Ignore SIGCHLD causing any terminated children to autoreap.
+	 * This speeds up the namespace shutdown, plus see the comment
+	 * below.
+	 */
+	spin_lock_irq(&me->sighand->siglock);
+	me->sighand->action[SIGCHLD - 1].sa.sa_handler = SIG_IGN;
+	spin_unlock_irq(&me->sighand->siglock);
+
+	/*
+	 * The last thread in the cgroup-init thread group is terminating.
+	 * Find remaining pid_ts in the namespace, signal and wait for them
+	 * to exit.
+	 *
+	 * Note:  This signals each threads in the namespace - even those that
+	 * 	  belong to the same thread group, To avoid this, we would have
+	 * 	  to walk the entire tasklist looking a processes in this
+	 * 	  namespace, but that could be unnecessarily expensive if the
+	 * 	  pid namespace has just a few processes. Or we need to
+	 * 	  maintain a tasklist for each pid namespace.
+	 *
+	 */
+	rcu_read_lock();
+	read_lock(&tasklist_lock);
+	nr = 2;
+	idr_for_each_entry_continue(&pid_ns->idr, pid, nr) {
+		task = pid_task(pid, PIDTYPE_PID);
+		if (task && !__fatal_signal_pending(task))
+			group_send_sig_info(SIGKILL, SEND_SIG_PRIV, task, PIDTYPE_MAX);
+	}
+	read_unlock(&tasklist_lock);
+	rcu_read_unlock();
+
+	/*
+	 * Reap the EXIT_ZOMBIE children we had before we ignored SIGCHLD.
+	 * kernel_wait4() will also block until our children traced from the
+	 * parent namespace are detached and become EXIT_DEAD.
+	 */
+	do {
+		clear_thread_flag(TIF_SIGPENDING);
+		rc = kernel_wait4(-1, NULL, __WALL, NULL);
+	} while (rc != -ECHILD);
+
+	/*
+	 * kernel_wait4() misses EXIT_DEAD children, and EXIT_ZOMBIE
+	 * process whose parents processes are outside of the pid
+	 * namespace.  Such processes are created with setns()+fork().
+	 *
+	 * If those EXIT_ZOMBIE processes are not reaped by their
+	 * parents before their parents exit, they will be reparented
+	 * to pid_ns->child_reaper.  Thus pidns->child_reaper needs to
+	 * stay valid until they all go away.
+	 *
+	 * The code relies on the pid_ns->child_reaper ignoring
+	 * SIGCHILD to cause those EXIT_ZOMBIE processes to be
+	 * autoreaped if reparented.
+	 *
+	 * Semantically it is also desirable to wait for EXIT_ZOMBIE
+	 * processes before allowing the child_reaper to be reaped, as
+	 * that gives the invariant that when the init process of a
+	 * pid namespace is reaped all of the processes in the pid
+	 * namespace are gone.
+	 *
+	 * Once all of the other tasks are gone from the pid_namespace
+	 * free_pid() will awaken this task.
+	 */
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (pid_ns->pid_allocated == init_pids)
+			break;
+		/*
+		 * Release tasks_rcu_exit_srcu to avoid following deadlock:
+		 *
+		 * 1) TASK A unshare(CLONE_NEWPID)
+		 * 2) TASK A fork() twice -> TASK B (child reaper for new ns)
+		 *    and TASK C
+		 * 3) TASK B exits, kills TASK C, waits for TASK A to reap it
+		 * 4) TASK A calls synchronize_rcu_tasks()
+		 *                   -> synchronize_srcu(tasks_rcu_exit_srcu)
+		 * 5) *DEADLOCK*
+		 *
+		 * It is considered safe to release tasks_rcu_exit_srcu here
+		 * because we assume the current task can not be concurrently
+		 * reaped at this point.
+		 */
+		exit_tasks_rcu_stop();
+		schedule();
+		exit_tasks_rcu_start();
+	}
+	__set_current_state(TASK_RUNNING);
+
+	if (pid_ns->reboot)
+		current->signal->group_exit_code = pid_ns->reboot;
+
+	acct_exit_ns(pid_ns);
+	return;
+}
+
+#ifdef CONFIG_CHECKPOINT_RESTORE
+static int pid_ns_ctl_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct pid_namespace *pid_ns = task_active_pid_ns(current);
+	struct ctl_table tmp = *table;
+	int ret, next;
+
+	if (write && !checkpoint_restore_ns_capable(pid_ns->user_ns))
+		return -EPERM;
+
+	/*
+	 * Writing directly to ns' last_pid field is OK, since this field
+	 * is volatile in a living namespace anyway and a code writing to
+	 * it should synchronize its usage with external means.
+	 */
+
+	next = idr_get_cursor(&pid_ns->idr) - 1;
+
+	tmp.data = &next;
+	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+	if (!ret && write)
+		idr_set_cursor(&pid_ns->idr, next + 1);
+
+	return ret;
+}
+
+extern int pid_max;
+static struct ctl_table pid_ns_ctl_table[] = {
+	{
+		.procname = "ns_last_pid",
+		.maxlen = sizeof(int),
+		.mode = 0666, /* permissions are checked in the handler */
+		.proc_handler = pid_ns_ctl_handler,
+		.extra1 = SYSCTL_ZERO,
+		.extra2 = &pid_max,
+	},
+	{ }
+};
+static struct ctl_path kern_path[] = { { .procname = "kernel", }, { } };
+#endif	/* CONFIG_CHECKPOINT_RESTORE */
+
+int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
+{
+	if (pid_ns == &init_pid_ns)
+		return 0;
+
+	switch (cmd) {
+	case LINUX_REBOOT_CMD_RESTART2:
+	case LINUX_REBOOT_CMD_RESTART:
+		pid_ns->reboot = SIGHUP;
+		break;
+
+	case LINUX_REBOOT_CMD_POWER_OFF:
+	case LINUX_REBOOT_CMD_HALT:
+		pid_ns->reboot = SIGINT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	read_lock(&tasklist_lock);
+	send_sig(SIGKILL, pid_ns->child_reaper, 1);
+	read_unlock(&tasklist_lock);
+
+	do_exit(0);
+
+	/* Not reached */
+	return 0;
+}
+
+static inline struct pid_namespace *to_pid_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct pid_namespace, ns);
+}
+
+static struct ns_common *pidns_get(struct task_struct *task)
+{
+	struct pid_namespace *ns;
+
+	rcu_read_lock();
+	ns = task_active_pid_ns(task);
+	if (ns)
+		get_pid_ns(ns);
+	rcu_read_unlock();
+
+	return ns ? &ns->ns : NULL;
+}
+
+static struct ns_common *pidns_for_children_get(struct task_struct *task)
+{
+	struct pid_namespace *ns = NULL;
+
+	task_lock(task);
+	if (task->nsproxy) {
+		ns = task->nsproxy->pid_ns_for_children;
+		get_pid_ns(ns);
+	}
+	task_unlock(task);
+
+	if (ns) {
+		read_lock(&tasklist_lock);
+		if (!ns->child_reaper) {
+			put_pid_ns(ns);
+			ns = NULL;
+		}
+		read_unlock(&tasklist_lock);
+	}
+
+	return ns ? &ns->ns : NULL;
+}
+
+static void pidns_put(struct ns_common *ns)
+{
+	put_pid_ns(to_pid_ns(ns));
+}
+
+static int pidns_install(struct nsset *nsset, struct ns_common *ns)
+{
+	struct nsproxy *nsproxy = nsset->nsproxy;
+	struct pid_namespace *active = task_active_pid_ns(current);
+	struct pid_namespace *ancestor, *new = to_pid_ns(ns);
+
+	if (!ns_capable(new->user_ns, CAP_SYS_ADMIN) ||
+	    !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	/*
+	 * Only allow entering the current active pid namespace
+	 * or a child of the current active pid namespace.
+	 *
+	 * This is required for fork to return a usable pid value and
+	 * this maintains the property that processes and their
+	 * children can not escape their current pid namespace.
+	 */
+	if (new->level < active->level)
+		return -EINVAL;
+
+	ancestor = new;
+	while (ancestor->level > active->level)
+		ancestor = ancestor->parent;
+	if (ancestor != active)
+		return -EINVAL;
+
+	put_pid_ns(nsproxy->pid_ns_for_children);
+	nsproxy->pid_ns_for_children = get_pid_ns(new);
+	return 0;
+}
+
+static struct ns_common *pidns_get_parent(struct ns_common *ns)
+{
+	struct pid_namespace *active = task_active_pid_ns(current);
+	struct pid_namespace *pid_ns, *p;
+
+	/* See if the parent is in the current namespace */
+	pid_ns = p = to_pid_ns(ns)->parent;
+	for (;;) {
+		if (!p)
+			return ERR_PTR(-EPERM);
+		if (p == active)
+			break;
+		p = p->parent;
+	}
+
+	return &get_pid_ns(pid_ns)->ns;
+}
+
+static struct user_namespace *pidns_owner(struct ns_common *ns)
+{
+	return to_pid_ns(ns)->user_ns;
+}
+
+const struct proc_ns_operations pidns_operations = {
+	.name		= "pid",
+	.type		= CLONE_NEWPID,
+	.get		= pidns_get,
+	.put		= pidns_put,
+	.install	= pidns_install,
+	.owner		= pidns_owner,
+	.get_parent	= pidns_get_parent,
+};
+
+const struct proc_ns_operations pidns_for_children_operations = {
+	.name		= "pid_for_children",
+	.real_ns_name	= "pid",
+	.type		= CLONE_NEWPID,
+	.get		= pidns_for_children_get,
+	.put		= pidns_put,
+	.install	= pidns_install,
+	.owner		= pidns_owner,
+	.get_parent	= pidns_get_parent,
+};
+
+static __init int pid_namespaces_init(void)
+{
+	pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC | SLAB_ACCOUNT);
+
+#ifdef CONFIG_CHECKPOINT_RESTORE
+	register_sysctl_paths(kern_path, pid_ns_ctl_table);
+#endif
+	return 0;
+}
+
+__initcall(pid_namespaces_init);
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
new file mode 100644
index 000000000..60a1d3051
--- /dev/null
+++ b/kernel/power/Kconfig
@@ -0,0 +1,353 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config SUSPEND
+	bool "Suspend to RAM and standby"
+	depends on ARCH_SUSPEND_POSSIBLE
+	default y
+	help
+	  Allow the system to enter sleep states in which main memory is
+	  powered and thus its contents are preserved, such as the
+	  suspend-to-RAM state (e.g. the ACPI S3 state).
+
+config SUSPEND_FREEZER
+	bool "Enable freezer for suspend to RAM/standby" \
+		if ARCH_WANTS_FREEZER_CONTROL || BROKEN
+	depends on SUSPEND
+	default y
+	help
+	  This allows you to turn off the freezer for suspend. If this is
+	  done, no tasks are frozen for suspend to RAM/standby.
+
+	  Turning OFF this setting is NOT recommended! If in doubt, say Y.
+
+config SUSPEND_SKIP_SYNC
+	bool "Skip kernel's sys_sync() on suspend to RAM/standby"
+	depends on SUSPEND
+	depends on EXPERT
+	help
+	  Skip the kernel sys_sync() before freezing user processes.
+	  Some systems prefer not to pay this cost on every invocation
+	  of suspend, or they are content with invoking sync() from
+	  user-space before invoking suspend.  There's a run-time switch
+	  at '/sys/power/sync_on_suspend' to configure this behaviour.
+	  This setting changes the default for the run-tim switch. Say Y
+	  to change the default to disable the kernel sys_sync().
+
+config HIBERNATE_CALLBACKS
+	bool
+
+config HIBERNATION
+	bool "Hibernation (aka 'suspend to disk')"
+	depends on SWAP && ARCH_HIBERNATION_POSSIBLE
+	select HIBERNATE_CALLBACKS
+	select LZO_COMPRESS
+	select LZO_DECOMPRESS
+	select CRC32
+	help
+	  Enable the suspend to disk (STD) functionality, which is usually
+	  called "hibernation" in user interfaces.  STD checkpoints the
+	  system and powers it off; and restores that checkpoint on reboot.
+
+	  You can suspend your machine with 'echo disk > /sys/power/state'
+	  after placing resume=/dev/swappartition on the kernel command line
+	  in your bootloader's configuration file.
+
+	  Alternatively, you can use the additional userland tools available
+	  from <http://suspend.sf.net>.
+
+	  In principle it does not require ACPI or APM, although for example
+	  ACPI will be used for the final steps when it is available.  One
+	  of the reasons to use software suspend is that the firmware hooks
+	  for suspend states like suspend-to-RAM (STR) often don't work very
+	  well with Linux.
+
+	  It creates an image which is saved in your active swap. Upon the next
+	  boot, pass the 'resume=/dev/swappartition' argument to the kernel to
+	  have it detect the saved image, restore memory state from it, and
+	  continue to run as before. If you do not want the previous state to
+	  be reloaded, then use the 'noresume' kernel command line argument.
+	  Note, however, that fsck will be run on your filesystems and you will
+	  need to run mkswap against the swap partition used for the suspend.
+
+	  It also works with swap files to a limited extent (for details see
+	  <file:Documentation/power/swsusp-and-swap-files.rst>).
+
+	  Right now you may boot without resuming and resume later but in the
+	  meantime you cannot use the swap partition(s)/file(s) involved in
+	  suspending.  Also in this case you must not use the filesystems
+	  that were mounted before the suspend.  In particular, you MUST NOT
+	  MOUNT any journaled filesystems mounted before the suspend or they
+	  will get corrupted in a nasty way.
+
+	  For more information take a look at <file:Documentation/power/swsusp.rst>.
+
+config HIBERNATION_SNAPSHOT_DEV
+	bool "Userspace snapshot device"
+	depends on HIBERNATION
+	default y
+	help
+	  Device used by the uswsusp tools.
+
+	  Say N if no snapshotting from userspace is needed, this also
+	  reduces the attack surface of the kernel.
+
+	  If in doubt, say Y.
+
+config PM_STD_PARTITION
+	string "Default resume partition"
+	depends on HIBERNATION
+	default ""
+	help
+	  The default resume partition is the partition that the suspend-
+	  to-disk implementation will look for a suspended disk image.
+
+	  The partition specified here will be different for almost every user.
+	  It should be a valid swap partition (at least for now) that is turned
+	  on before suspending.
+
+	  The partition specified can be overridden by specifying:
+
+		resume=/dev/<other device>
+
+	  which will set the resume partition to the device specified.
+
+	  Note there is currently not a way to specify which device to save the
+	  suspended image to. It will simply pick the first available swap
+	  device.
+
+config PM_SLEEP
+	def_bool y
+	depends on SUSPEND || HIBERNATE_CALLBACKS
+	select PM
+	select SRCU
+
+config PM_SLEEP_SMP
+	def_bool y
+	depends on SMP
+	depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
+	depends on PM_SLEEP
+	select HOTPLUG_CPU
+
+config PM_SLEEP_SMP_NONZERO_CPU
+	def_bool y
+	depends on PM_SLEEP_SMP
+	depends on ARCH_SUSPEND_NONZERO_CPU
+	help
+	If an arch can suspend (for suspend, hibernate, kexec, etc) on a
+	non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This
+	will allow nohz_full mask to include CPU0.
+
+config PM_AUTOSLEEP
+	bool "Opportunistic sleep"
+	depends on PM_SLEEP
+	help
+	Allow the kernel to trigger a system transition into a global sleep
+	state automatically whenever there are no active wakeup sources.
+
+config PM_USERSPACE_AUTOSLEEP
+	bool "Userspace opportunistic sleep"
+	depends on PM_SLEEP
+	help
+	Notify kernel of aggressive userspace autosleep power management policy.
+
+	This option changes the behavior of various sleep-sensitive code to deal
+	with frequent userspace-initiated transitions into a global sleep state.
+
+	Saying Y here, disables code paths that most users really should keep
+	enabled. In particular, only enable this if it is very common to be
+	asleep/awake for very short periods of time (<= 2 seconds).
+
+	Only platforms, such as Android, that implement opportunistic sleep from
+	a userspace power manager service should enable this option; and not
+	other machines. Therefore, you should say N here, unless you are
+	extremely certain that this is what you want. The option otherwise has
+	bad, undesirable effects, and should not be enabled just for fun.
+
+
+config PM_WAKELOCKS
+	bool "User space wakeup sources interface"
+	depends on PM_SLEEP
+	help
+	Allow user space to create, activate and deactivate wakeup source
+	objects with the help of a sysfs-based interface.
+
+config PM_WAKELOCKS_LIMIT
+	int "Maximum number of user space wakeup sources (0 = no limit)"
+	range 0 100000
+	default 100
+	depends on PM_WAKELOCKS
+
+config PM_WAKELOCKS_GC
+	bool "Garbage collector for user space wakeup sources"
+	depends on PM_WAKELOCKS
+	default y
+
+config PM
+	bool "Device power management core functionality"
+	help
+	  Enable functionality allowing I/O devices to be put into energy-saving
+	  (low power) states, for example after a specified period of inactivity
+	  (autosuspended), and woken up in response to a hardware-generated
+	  wake-up event or a driver's request.
+
+	  Hardware support is generally required for this functionality to work
+	  and the bus type drivers of the buses the devices are on are
+	  responsible for the actual handling of device suspend requests and
+	  wake-up events.
+
+config PM_DEBUG
+	bool "Power Management Debug Support"
+	depends on PM
+	help
+	This option enables various debugging support in the Power Management
+	code. This is helpful when debugging and reporting PM bugs, like
+	suspend support.
+
+config PM_ADVANCED_DEBUG
+	bool "Extra PM attributes in sysfs for low-level debugging/testing"
+	depends on PM_DEBUG
+	help
+	Add extra sysfs attributes allowing one to access some Power Management
+	fields of device objects from user space.  If you are not a kernel
+	developer interested in debugging/testing Power Management, say "no".
+
+config PM_TEST_SUSPEND
+	bool "Test suspend/resume and wakealarm during bootup"
+	depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
+	help
+	This option will let you suspend your machine during bootup, and
+	make it wake up a few seconds later using an RTC wakeup alarm.
+	Enable this with a kernel parameter like "test_suspend=mem".
+
+	You probably want to have your system's RTC driver statically
+	linked, ensuring that it's available when this test runs.
+
+config PM_SLEEP_DEBUG
+	def_bool y
+	depends on PM_DEBUG && PM_SLEEP
+
+config DPM_WATCHDOG
+	bool "Device suspend/resume watchdog"
+	depends on PM_DEBUG && PSTORE && EXPERT
+	help
+	  Sets up a watchdog timer to capture drivers that are
+	  locked up attempting to suspend/resume a device.
+	  A detected lockup causes system panic with message
+	  captured in pstore device for inspection in subsequent
+	  boot session.
+
+config DPM_WATCHDOG_TIMEOUT
+	int "Watchdog timeout in seconds"
+	range 1 120
+	default 120
+	depends on DPM_WATCHDOG
+
+config PM_TRACE
+	bool
+	help
+	  This enables code to save the last PM event point across
+	  reboot. The architecture needs to support this, x86 for
+	  example does by saving things in the RTC, see below.
+
+	  The architecture specific code must provide the extern
+	  functions from <linux/resume-trace.h> as well as the
+	  <asm/resume-trace.h> header with a TRACE_RESUME() macro.
+
+	  The way the information is presented is architecture-
+	  dependent, x86 will print the information during a
+	  late_initcall.
+
+config PM_TRACE_RTC
+	bool "Suspend/resume event tracing"
+	depends on PM_SLEEP_DEBUG
+	depends on X86
+	select PM_TRACE
+	help
+	This enables some cheesy code to save the last PM event point in the
+	RTC across reboots, so that you can debug a machine that just hangs
+	during suspend (or more commonly, during resume).
+
+	To use this debugging feature you should attempt to suspend the
+	machine, reboot it and then run
+
+		dmesg -s 1000000 | grep 'hash matches'
+
+	CAUTION: this option will cause your machine's real-time clock to be
+	set to an invalid time after a resume.
+
+config APM_EMULATION
+	tristate "Advanced Power Management Emulation"
+	depends on SYS_SUPPORTS_APM_EMULATION
+	help
+	  APM is a BIOS specification for saving power using several different
+	  techniques. This is mostly useful for battery powered laptops with
+	  APM compliant BIOSes. If you say Y here, the system time will be
+	  reset after a RESUME operation, the /proc/apm device will provide
+	  battery status information, and user-space programs will receive
+	  notification of APM "events" (e.g. battery status change).
+
+	  In order to use APM, you will need supporting software. For location
+	  and more information, read <file:Documentation/power/apm-acpi.rst>
+	  and the Battery Powered Linux mini-HOWTO, available from
+	  <http://www.tldp.org/docs.html#howto>.
+
+	  This driver does not spin down disk drives (see the hdparm(8)
+	  manpage ("man 8 hdparm") for that), and it doesn't turn off
+	  VESA-compliant "green" monitors.
+
+	  Generally, if you don't have a battery in your machine, there isn't
+	  much point in using this driver and you should say N. If you get
+	  random kernel OOPSes or reboots that don't seem to be related to
+	  anything, try disabling/enabling this option (or disabling/enabling
+	  APM in your BIOS).
+
+config PM_CLK
+	def_bool y
+	depends on PM && HAVE_CLK
+
+config PM_GENERIC_DOMAINS
+	bool
+	depends on PM
+
+config WQ_POWER_EFFICIENT_DEFAULT
+	bool "Enable workqueue power-efficient mode by default"
+	depends on PM
+	help
+	  Per-cpu workqueues are generally preferred because they show
+	  better performance thanks to cache locality; unfortunately,
+	  per-cpu workqueues tend to be more power hungry than unbound
+	  workqueues.
+
+	  Enabling workqueue.power_efficient kernel parameter makes the
+	  per-cpu workqueues which were observed to contribute
+	  significantly to power consumption unbound, leading to measurably
+	  lower power usage at the cost of small performance overhead.
+
+	  This config option determines whether workqueue.power_efficient
+	  is enabled by default.
+
+	  If in doubt, say N.
+
+config PM_GENERIC_DOMAINS_SLEEP
+	def_bool y
+	depends on PM_SLEEP && PM_GENERIC_DOMAINS
+
+config PM_GENERIC_DOMAINS_OF
+	def_bool y
+	depends on PM_GENERIC_DOMAINS && OF
+
+config CPU_PM
+	bool
+
+config ENERGY_MODEL
+	bool "Energy Model for devices with DVFS (CPUs, GPUs, etc)"
+	depends on SMP
+	depends on CPU_FREQ
+	help
+	  Several subsystems (thermal and/or the task scheduler for example)
+	  can leverage information about the energy consumed by devices to
+	  make smarter decisions. This config option enables the framework
+	  from which subsystems can access the energy models.
+
+	  The exact usage of the energy model is subsystem-dependent.
+
+	  If in doubt, say N.
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
new file mode 100644
index 000000000..874ad834d
--- /dev/null
+++ b/kernel/power/Makefile
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: GPL-2.0
+
+ifeq ($(CONFIG_DYNAMIC_DEBUG), y)
+CFLAGS_swap.o                   := -DDEBUG
+CFLAGS_snapshot.o               := -DDEBUG
+CFLAGS_energy_model.o           := -DDEBUG
+endif
+
+KASAN_SANITIZE_snapshot.o	:= n
+
+obj-y				+= qos.o
+obj-$(CONFIG_PM)		+= main.o
+obj-$(CONFIG_VT_CONSOLE_SLEEP)	+= console.o
+obj-$(CONFIG_FREEZER)		+= process.o
+obj-$(CONFIG_SUSPEND)		+= suspend.o
+obj-$(CONFIG_PM_TEST_SUSPEND)	+= suspend_test.o
+obj-$(CONFIG_HIBERNATION)	+= hibernate.o snapshot.o swap.o
+obj-$(CONFIG_HIBERNATION_SNAPSHOT_DEV) += user.o
+obj-$(CONFIG_PM_AUTOSLEEP)	+= autosleep.o
+obj-$(CONFIG_PM_WAKELOCKS)	+= wakelock.o
+
+obj-$(CONFIG_MAGIC_SYSRQ)	+= poweroff.o
+
+obj-$(CONFIG_ENERGY_MODEL)	+= energy_model.o
diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c
new file mode 100644
index 000000000..b29c8aca7
--- /dev/null
+++ b/kernel/power/autosleep.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kernel/power/autosleep.c
+ *
+ * Opportunistic sleep support.
+ *
+ * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
+ */
+
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/pm_wakeup.h>
+
+#include "power.h"
+
+static suspend_state_t autosleep_state;
+static struct workqueue_struct *autosleep_wq;
+/*
+ * Note: it is only safe to mutex_lock(&autosleep_lock) if a wakeup_source
+ * is active, otherwise a deadlock with try_to_suspend() is possible.
+ * Alternatively mutex_lock_interruptible() can be used.  This will then fail
+ * if an auto_sleep cycle tries to freeze processes.
+ */
+static DEFINE_MUTEX(autosleep_lock);
+static struct wakeup_source *autosleep_ws;
+
+static void try_to_suspend(struct work_struct *work)
+{
+	unsigned int initial_count, final_count;
+
+	if (!pm_get_wakeup_count(&initial_count, true))
+		goto out;
+
+	mutex_lock(&autosleep_lock);
+
+	if (!pm_save_wakeup_count(initial_count) ||
+		system_state != SYSTEM_RUNNING) {
+		mutex_unlock(&autosleep_lock);
+		goto out;
+	}
+
+	if (autosleep_state == PM_SUSPEND_ON) {
+		mutex_unlock(&autosleep_lock);
+		return;
+	}
+	if (autosleep_state >= PM_SUSPEND_MAX)
+		hibernate();
+	else
+		pm_suspend(autosleep_state);
+
+	mutex_unlock(&autosleep_lock);
+
+	if (!pm_get_wakeup_count(&final_count, false))
+		goto out;
+
+	/*
+	 * If the wakeup occurred for an unknown reason, wait to prevent the
+	 * system from trying to suspend and waking up in a tight loop.
+	 */
+	if (final_count == initial_count)
+		schedule_timeout_uninterruptible(HZ / 2);
+
+ out:
+	queue_up_suspend_work();
+}
+
+static DECLARE_WORK(suspend_work, try_to_suspend);
+
+void queue_up_suspend_work(void)
+{
+	if (autosleep_state > PM_SUSPEND_ON)
+		queue_work(autosleep_wq, &suspend_work);
+}
+
+suspend_state_t pm_autosleep_state(void)
+{
+	return autosleep_state;
+}
+
+int pm_autosleep_lock(void)
+{
+	return mutex_lock_interruptible(&autosleep_lock);
+}
+
+void pm_autosleep_unlock(void)
+{
+	mutex_unlock(&autosleep_lock);
+}
+
+int pm_autosleep_set_state(suspend_state_t state)
+{
+
+#ifndef CONFIG_HIBERNATION
+	if (state >= PM_SUSPEND_MAX)
+		return -EINVAL;
+#endif
+
+	__pm_stay_awake(autosleep_ws);
+
+	mutex_lock(&autosleep_lock);
+
+	autosleep_state = state;
+
+	__pm_relax(autosleep_ws);
+
+	if (state > PM_SUSPEND_ON) {
+		pm_wakep_autosleep_enabled(true);
+		queue_up_suspend_work();
+	} else {
+		pm_wakep_autosleep_enabled(false);
+	}
+
+	mutex_unlock(&autosleep_lock);
+	return 0;
+}
+
+int __init pm_autosleep_init(void)
+{
+	autosleep_ws = wakeup_source_register(NULL, "autosleep");
+	if (!autosleep_ws)
+		return -ENOMEM;
+
+	autosleep_wq = alloc_ordered_workqueue("autosleep", 0);
+	if (autosleep_wq)
+		return 0;
+
+	wakeup_source_unregister(autosleep_ws);
+	return -ENOMEM;
+}
diff --git a/kernel/power/console.c b/kernel/power/console.c
new file mode 100644
index 000000000..fcdf0e14a
--- /dev/null
+++ b/kernel/power/console.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions for saving/restoring console.
+ *
+ * Originally from swsusp.
+ */
+
+#include <linux/console.h>
+#include <linux/vt_kern.h>
+#include <linux/kbd_kern.h>
+#include <linux/vt.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include "power.h"
+
+#define SUSPEND_CONSOLE	(MAX_NR_CONSOLES-1)
+
+static int orig_fgconsole, orig_kmsg;
+
+static DEFINE_MUTEX(vt_switch_mutex);
+
+struct pm_vt_switch {
+	struct list_head head;
+	struct device *dev;
+	bool required;
+};
+
+static LIST_HEAD(pm_vt_switch_list);
+
+
+/**
+ * pm_vt_switch_required - indicate VT switch at suspend requirements
+ * @dev: device
+ * @required: if true, caller needs VT switch at suspend/resume time
+ *
+ * The different console drivers may or may not require VT switches across
+ * suspend/resume, depending on how they handle restoring video state and
+ * what may be running.
+ *
+ * Drivers can indicate support for switchless suspend/resume, which can
+ * save time and flicker, by using this routine and passing 'false' as
+ * the argument.  If any loaded driver needs VT switching, or the
+ * no_console_suspend argument has been passed on the command line, VT
+ * switches will occur.
+ */
+void pm_vt_switch_required(struct device *dev, bool required)
+{
+	struct pm_vt_switch *entry, *tmp;
+
+	mutex_lock(&vt_switch_mutex);
+	list_for_each_entry(tmp, &pm_vt_switch_list, head) {
+		if (tmp->dev == dev) {
+			/* already registered, update requirement */
+			tmp->required = required;
+			goto out;
+		}
+	}
+
+	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		goto out;
+
+	entry->required = required;
+	entry->dev = dev;
+
+	list_add(&entry->head, &pm_vt_switch_list);
+out:
+	mutex_unlock(&vt_switch_mutex);
+}
+EXPORT_SYMBOL(pm_vt_switch_required);
+
+/**
+ * pm_vt_switch_unregister - stop tracking a device's VT switching needs
+ * @dev: device
+ *
+ * Remove @dev from the vt switch list.
+ */
+void pm_vt_switch_unregister(struct device *dev)
+{
+	struct pm_vt_switch *tmp;
+
+	mutex_lock(&vt_switch_mutex);
+	list_for_each_entry(tmp, &pm_vt_switch_list, head) {
+		if (tmp->dev == dev) {
+			list_del(&tmp->head);
+			kfree(tmp);
+			break;
+		}
+	}
+	mutex_unlock(&vt_switch_mutex);
+}
+EXPORT_SYMBOL(pm_vt_switch_unregister);
+
+/*
+ * There are three cases when a VT switch on suspend/resume are required:
+ *   1) no driver has indicated a requirement one way or another, so preserve
+ *      the old behavior
+ *   2) console suspend is disabled, we want to see debug messages across
+ *      suspend/resume
+ *   3) any registered driver indicates it needs a VT switch
+ *
+ * If none of these conditions is present, meaning we have at least one driver
+ * that doesn't need the switch, and none that do, we can avoid it to make
+ * resume look a little prettier (and suspend too, but that's usually hidden,
+ * e.g. when closing the lid on a laptop).
+ */
+static bool pm_vt_switch(void)
+{
+	struct pm_vt_switch *entry;
+	bool ret = true;
+
+	mutex_lock(&vt_switch_mutex);
+	if (list_empty(&pm_vt_switch_list))
+		goto out;
+
+	if (!console_suspend_enabled)
+		goto out;
+
+	list_for_each_entry(entry, &pm_vt_switch_list, head) {
+		if (entry->required)
+			goto out;
+	}
+
+	ret = false;
+out:
+	mutex_unlock(&vt_switch_mutex);
+	return ret;
+}
+
+void pm_prepare_console(void)
+{
+	if (!pm_vt_switch())
+		return;
+
+	orig_fgconsole = vt_move_to_console(SUSPEND_CONSOLE, 1);
+	if (orig_fgconsole < 0)
+		return;
+
+	orig_kmsg = vt_kmsg_redirect(SUSPEND_CONSOLE);
+	return;
+}
+
+void pm_restore_console(void)
+{
+	if (!pm_vt_switch())
+		return;
+
+	if (orig_fgconsole >= 0) {
+		vt_move_to_console(orig_fgconsole, 0);
+		vt_kmsg_redirect(orig_kmsg);
+	}
+}
diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
new file mode 100644
index 000000000..7b44f5b89
--- /dev/null
+++ b/kernel/power/energy_model.c
@@ -0,0 +1,438 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Energy Model of devices
+ *
+ * Copyright (c) 2018-2021, Arm ltd.
+ * Written by: Quentin Perret, Arm ltd.
+ * Improvements provided by: Lukasz Luba, Arm ltd.
+ */
+
+#define pr_fmt(fmt) "energy_model: " fmt
+
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/cpumask.h>
+#include <linux/debugfs.h>
+#include <linux/energy_model.h>
+#include <linux/sched/topology.h>
+#include <linux/slab.h>
+
+/*
+ * Mutex serializing the registrations of performance domains and letting
+ * callbacks defined by drivers sleep.
+ */
+static DEFINE_MUTEX(em_pd_mutex);
+
+static bool _is_cpu_device(struct device *dev)
+{
+	return (dev->bus == &cpu_subsys);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static struct dentry *rootdir;
+
+static void em_debug_create_ps(struct em_perf_state *ps, struct dentry *pd)
+{
+	struct dentry *d;
+	char name[24];
+
+	snprintf(name, sizeof(name), "ps:%lu", ps->frequency);
+
+	/* Create per-ps directory */
+	d = debugfs_create_dir(name, pd);
+	debugfs_create_ulong("frequency", 0444, d, &ps->frequency);
+	debugfs_create_ulong("power", 0444, d, &ps->power);
+	debugfs_create_ulong("cost", 0444, d, &ps->cost);
+	debugfs_create_ulong("inefficient", 0444, d, &ps->flags);
+}
+
+static int em_debug_cpus_show(struct seq_file *s, void *unused)
+{
+	seq_printf(s, "%*pbl\n", cpumask_pr_args(to_cpumask(s->private)));
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(em_debug_cpus);
+
+static int em_debug_flags_show(struct seq_file *s, void *unused)
+{
+	struct em_perf_domain *pd = s->private;
+
+	seq_printf(s, "%#lx\n", pd->flags);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(em_debug_flags);
+
+static void em_debug_create_pd(struct device *dev)
+{
+	struct dentry *d;
+	int i;
+
+	/* Create the directory of the performance domain */
+	d = debugfs_create_dir(dev_name(dev), rootdir);
+
+	if (_is_cpu_device(dev))
+		debugfs_create_file("cpus", 0444, d, dev->em_pd->cpus,
+				    &em_debug_cpus_fops);
+
+	debugfs_create_file("flags", 0444, d, dev->em_pd,
+			    &em_debug_flags_fops);
+
+	/* Create a sub-directory for each performance state */
+	for (i = 0; i < dev->em_pd->nr_perf_states; i++)
+		em_debug_create_ps(&dev->em_pd->table[i], d);
+
+}
+
+static void em_debug_remove_pd(struct device *dev)
+{
+	debugfs_lookup_and_remove(dev_name(dev), rootdir);
+}
+
+static int __init em_debug_init(void)
+{
+	/* Create /sys/kernel/debug/energy_model directory */
+	rootdir = debugfs_create_dir("energy_model", NULL);
+
+	return 0;
+}
+fs_initcall(em_debug_init);
+#else /* CONFIG_DEBUG_FS */
+static void em_debug_create_pd(struct device *dev) {}
+static void em_debug_remove_pd(struct device *dev) {}
+#endif
+
+static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
+				int nr_states, struct em_data_callback *cb,
+				unsigned long flags)
+{
+	unsigned long power, freq, prev_freq = 0, prev_cost = ULONG_MAX;
+	struct em_perf_state *table;
+	int i, ret;
+	u64 fmax;
+
+	table = kcalloc(nr_states, sizeof(*table), GFP_KERNEL);
+	if (!table)
+		return -ENOMEM;
+
+	/* Build the list of performance states for this performance domain */
+	for (i = 0, freq = 0; i < nr_states; i++, freq++) {
+		/*
+		 * active_power() is a driver callback which ceils 'freq' to
+		 * lowest performance state of 'dev' above 'freq' and updates
+		 * 'power' and 'freq' accordingly.
+		 */
+		ret = cb->active_power(dev, &power, &freq);
+		if (ret) {
+			dev_err(dev, "EM: invalid perf. state: %d\n",
+				ret);
+			goto free_ps_table;
+		}
+
+		/*
+		 * We expect the driver callback to increase the frequency for
+		 * higher performance states.
+		 */
+		if (freq <= prev_freq) {
+			dev_err(dev, "EM: non-increasing freq: %lu\n",
+				freq);
+			goto free_ps_table;
+		}
+
+		/*
+		 * The power returned by active_state() is expected to be
+		 * positive and be in range.
+		 */
+		if (!power || power > EM_MAX_POWER) {
+			dev_err(dev, "EM: invalid power: %lu\n",
+				power);
+			goto free_ps_table;
+		}
+
+		table[i].power = power;
+		table[i].frequency = prev_freq = freq;
+	}
+
+	/* Compute the cost of each performance state. */
+	fmax = (u64) table[nr_states - 1].frequency;
+	for (i = nr_states - 1; i >= 0; i--) {
+		unsigned long power_res, cost;
+
+		if (flags & EM_PERF_DOMAIN_ARTIFICIAL) {
+			ret = cb->get_cost(dev, table[i].frequency, &cost);
+			if (ret || !cost || cost > EM_MAX_POWER) {
+				dev_err(dev, "EM: invalid cost %lu %d\n",
+					cost, ret);
+				goto free_ps_table;
+			}
+		} else {
+			power_res = table[i].power;
+			cost = div64_u64(fmax * power_res, table[i].frequency);
+		}
+
+		table[i].cost = cost;
+
+		if (table[i].cost >= prev_cost) {
+			table[i].flags = EM_PERF_STATE_INEFFICIENT;
+			dev_dbg(dev, "EM: OPP:%lu is inefficient\n",
+				table[i].frequency);
+		} else {
+			prev_cost = table[i].cost;
+		}
+	}
+
+	pd->table = table;
+	pd->nr_perf_states = nr_states;
+
+	return 0;
+
+free_ps_table:
+	kfree(table);
+	return -EINVAL;
+}
+
+static int em_create_pd(struct device *dev, int nr_states,
+			struct em_data_callback *cb, cpumask_t *cpus,
+			unsigned long flags)
+{
+	struct em_perf_domain *pd;
+	struct device *cpu_dev;
+	int cpu, ret, num_cpus;
+
+	if (_is_cpu_device(dev)) {
+		num_cpus = cpumask_weight(cpus);
+
+		/* Prevent max possible energy calculation to not overflow */
+		if (num_cpus > EM_MAX_NUM_CPUS) {
+			dev_err(dev, "EM: too many CPUs, overflow possible\n");
+			return -EINVAL;
+		}
+
+		pd = kzalloc(sizeof(*pd) + cpumask_size(), GFP_KERNEL);
+		if (!pd)
+			return -ENOMEM;
+
+		cpumask_copy(em_span_cpus(pd), cpus);
+	} else {
+		pd = kzalloc(sizeof(*pd), GFP_KERNEL);
+		if (!pd)
+			return -ENOMEM;
+	}
+
+	ret = em_create_perf_table(dev, pd, nr_states, cb, flags);
+	if (ret) {
+		kfree(pd);
+		return ret;
+	}
+
+	if (_is_cpu_device(dev))
+		for_each_cpu(cpu, cpus) {
+			cpu_dev = get_cpu_device(cpu);
+			cpu_dev->em_pd = pd;
+		}
+
+	dev->em_pd = pd;
+
+	return 0;
+}
+
+static void em_cpufreq_update_efficiencies(struct device *dev)
+{
+	struct em_perf_domain *pd = dev->em_pd;
+	struct em_perf_state *table;
+	struct cpufreq_policy *policy;
+	int found = 0;
+	int i;
+
+	if (!_is_cpu_device(dev) || !pd)
+		return;
+
+	policy = cpufreq_cpu_get(cpumask_first(em_span_cpus(pd)));
+	if (!policy) {
+		dev_warn(dev, "EM: Access to CPUFreq policy failed");
+		return;
+	}
+
+	table = pd->table;
+
+	for (i = 0; i < pd->nr_perf_states; i++) {
+		if (!(table[i].flags & EM_PERF_STATE_INEFFICIENT))
+			continue;
+
+		if (!cpufreq_table_set_inefficient(policy, table[i].frequency))
+			found++;
+	}
+
+	cpufreq_cpu_put(policy);
+
+	if (!found)
+		return;
+
+	/*
+	 * Efficiencies have been installed in CPUFreq, inefficient frequencies
+	 * will be skipped. The EM can do the same.
+	 */
+	pd->flags |= EM_PERF_DOMAIN_SKIP_INEFFICIENCIES;
+}
+
+/**
+ * em_pd_get() - Return the performance domain for a device
+ * @dev : Device to find the performance domain for
+ *
+ * Returns the performance domain to which @dev belongs, or NULL if it doesn't
+ * exist.
+ */
+struct em_perf_domain *em_pd_get(struct device *dev)
+{
+	if (IS_ERR_OR_NULL(dev))
+		return NULL;
+
+	return dev->em_pd;
+}
+EXPORT_SYMBOL_GPL(em_pd_get);
+
+/**
+ * em_cpu_get() - Return the performance domain for a CPU
+ * @cpu : CPU to find the performance domain for
+ *
+ * Returns the performance domain to which @cpu belongs, or NULL if it doesn't
+ * exist.
+ */
+struct em_perf_domain *em_cpu_get(int cpu)
+{
+	struct device *cpu_dev;
+
+	cpu_dev = get_cpu_device(cpu);
+	if (!cpu_dev)
+		return NULL;
+
+	return em_pd_get(cpu_dev);
+}
+EXPORT_SYMBOL_GPL(em_cpu_get);
+
+/**
+ * em_dev_register_perf_domain() - Register the Energy Model (EM) for a device
+ * @dev		: Device for which the EM is to register
+ * @nr_states	: Number of performance states to register
+ * @cb		: Callback functions providing the data of the Energy Model
+ * @cpus	: Pointer to cpumask_t, which in case of a CPU device is
+ *		obligatory. It can be taken from i.e. 'policy->cpus'. For other
+ *		type of devices this should be set to NULL.
+ * @microwatts	: Flag indicating that the power values are in micro-Watts or
+ *		in some other scale. It must be set properly.
+ *
+ * Create Energy Model tables for a performance domain using the callbacks
+ * defined in cb.
+ *
+ * The @microwatts is important to set with correct value. Some kernel
+ * sub-systems might rely on this flag and check if all devices in the EM are
+ * using the same scale.
+ *
+ * If multiple clients register the same performance domain, all but the first
+ * registration will be ignored.
+ *
+ * Return 0 on success
+ */
+int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
+				struct em_data_callback *cb, cpumask_t *cpus,
+				bool microwatts)
+{
+	unsigned long cap, prev_cap = 0;
+	unsigned long flags = 0;
+	int cpu, ret;
+
+	if (!dev || !nr_states || !cb)
+		return -EINVAL;
+
+	/*
+	 * Use a mutex to serialize the registration of performance domains and
+	 * let the driver-defined callback functions sleep.
+	 */
+	mutex_lock(&em_pd_mutex);
+
+	if (dev->em_pd) {
+		ret = -EEXIST;
+		goto unlock;
+	}
+
+	if (_is_cpu_device(dev)) {
+		if (!cpus) {
+			dev_err(dev, "EM: invalid CPU mask\n");
+			ret = -EINVAL;
+			goto unlock;
+		}
+
+		for_each_cpu(cpu, cpus) {
+			if (em_cpu_get(cpu)) {
+				dev_err(dev, "EM: exists for CPU%d\n", cpu);
+				ret = -EEXIST;
+				goto unlock;
+			}
+			/*
+			 * All CPUs of a domain must have the same
+			 * micro-architecture since they all share the same
+			 * table.
+			 */
+			cap = arch_scale_cpu_capacity(cpu);
+			if (prev_cap && prev_cap != cap) {
+				dev_err(dev, "EM: CPUs of %*pbl must have the same capacity\n",
+					cpumask_pr_args(cpus));
+
+				ret = -EINVAL;
+				goto unlock;
+			}
+			prev_cap = cap;
+		}
+	}
+
+	if (microwatts)
+		flags |= EM_PERF_DOMAIN_MICROWATTS;
+	else if (cb->get_cost)
+		flags |= EM_PERF_DOMAIN_ARTIFICIAL;
+
+	ret = em_create_pd(dev, nr_states, cb, cpus, flags);
+	if (ret)
+		goto unlock;
+
+	dev->em_pd->flags |= flags;
+
+	em_cpufreq_update_efficiencies(dev);
+
+	em_debug_create_pd(dev);
+	dev_info(dev, "EM: created perf domain\n");
+
+unlock:
+	mutex_unlock(&em_pd_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(em_dev_register_perf_domain);
+
+/**
+ * em_dev_unregister_perf_domain() - Unregister Energy Model (EM) for a device
+ * @dev		: Device for which the EM is registered
+ *
+ * Unregister the EM for the specified @dev (but not a CPU device).
+ */
+void em_dev_unregister_perf_domain(struct device *dev)
+{
+	if (IS_ERR_OR_NULL(dev) || !dev->em_pd)
+		return;
+
+	if (_is_cpu_device(dev))
+		return;
+
+	/*
+	 * The mutex separates all register/unregister requests and protects
+	 * from potential clean-up/setup issues in the debugfs directories.
+	 * The debugfs directory name is the same as device's name.
+	 */
+	mutex_lock(&em_pd_mutex);
+	em_debug_remove_pd(dev);
+
+	kfree(dev->em_pd->table);
+	kfree(dev->em_pd);
+	dev->em_pd = NULL;
+	mutex_unlock(&em_pd_mutex);
+}
+EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain);
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
new file mode 100644
index 000000000..30d1274f0
--- /dev/null
+++ b/kernel/power/hibernate.c
@@ -0,0 +1,1367 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/power/hibernate.c - Hibernation (a.k.a suspend-to-disk) support.
+ *
+ * Copyright (c) 2003 Patrick Mochel
+ * Copyright (c) 2003 Open Source Development Lab
+ * Copyright (c) 2004 Pavel Machek <pavel@ucw.cz>
+ * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc.
+ * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com>
+ */
+
+#define pr_fmt(fmt) "PM: hibernation: " fmt
+
+#include <linux/export.h>
+#include <linux/suspend.h>
+#include <linux/reboot.h>
+#include <linux/string.h>
+#include <linux/device.h>
+#include <linux/async.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/pm.h>
+#include <linux/nmi.h>
+#include <linux/console.h>
+#include <linux/cpu.h>
+#include <linux/freezer.h>
+#include <linux/gfp.h>
+#include <linux/syscore_ops.h>
+#include <linux/ctype.h>
+#include <linux/ktime.h>
+#include <linux/security.h>
+#include <linux/secretmem.h>
+#include <trace/events/power.h>
+
+#include "power.h"
+
+
+static int nocompress;
+static int noresume;
+static int nohibernate;
+static int resume_wait;
+static unsigned int resume_delay;
+static char resume_file[256] = CONFIG_PM_STD_PARTITION;
+dev_t swsusp_resume_device;
+sector_t swsusp_resume_block;
+__visible int in_suspend __nosavedata;
+
+enum {
+	HIBERNATION_INVALID,
+	HIBERNATION_PLATFORM,
+	HIBERNATION_SHUTDOWN,
+	HIBERNATION_REBOOT,
+#ifdef CONFIG_SUSPEND
+	HIBERNATION_SUSPEND,
+#endif
+	HIBERNATION_TEST_RESUME,
+	/* keep last */
+	__HIBERNATION_AFTER_LAST
+};
+#define HIBERNATION_MAX (__HIBERNATION_AFTER_LAST-1)
+#define HIBERNATION_FIRST (HIBERNATION_INVALID + 1)
+
+static int hibernation_mode = HIBERNATION_SHUTDOWN;
+
+bool freezer_test_done;
+bool snapshot_test;
+
+static const struct platform_hibernation_ops *hibernation_ops;
+
+static atomic_t hibernate_atomic = ATOMIC_INIT(1);
+
+bool hibernate_acquire(void)
+{
+	return atomic_add_unless(&hibernate_atomic, -1, 0);
+}
+
+void hibernate_release(void)
+{
+	atomic_inc(&hibernate_atomic);
+}
+
+bool hibernation_available(void)
+{
+	return nohibernate == 0 &&
+		!security_locked_down(LOCKDOWN_HIBERNATION) &&
+		!secretmem_active() && !cxl_mem_active();
+}
+
+/**
+ * hibernation_set_ops - Set the global hibernate operations.
+ * @ops: Hibernation operations to use in subsequent hibernation transitions.
+ */
+void hibernation_set_ops(const struct platform_hibernation_ops *ops)
+{
+	unsigned int sleep_flags;
+
+	if (ops && !(ops->begin && ops->end &&  ops->pre_snapshot
+	    && ops->prepare && ops->finish && ops->enter && ops->pre_restore
+	    && ops->restore_cleanup && ops->leave)) {
+		WARN_ON(1);
+		return;
+	}
+
+	sleep_flags = lock_system_sleep();
+
+	hibernation_ops = ops;
+	if (ops)
+		hibernation_mode = HIBERNATION_PLATFORM;
+	else if (hibernation_mode == HIBERNATION_PLATFORM)
+		hibernation_mode = HIBERNATION_SHUTDOWN;
+
+	unlock_system_sleep(sleep_flags);
+}
+EXPORT_SYMBOL_GPL(hibernation_set_ops);
+
+static bool entering_platform_hibernation;
+
+bool system_entering_hibernation(void)
+{
+	return entering_platform_hibernation;
+}
+EXPORT_SYMBOL(system_entering_hibernation);
+
+#ifdef CONFIG_PM_DEBUG
+static void hibernation_debug_sleep(void)
+{
+	pr_info("debug: Waiting for 5 seconds.\n");
+	mdelay(5000);
+}
+
+static int hibernation_test(int level)
+{
+	if (pm_test_level == level) {
+		hibernation_debug_sleep();
+		return 1;
+	}
+	return 0;
+}
+#else /* !CONFIG_PM_DEBUG */
+static int hibernation_test(int level) { return 0; }
+#endif /* !CONFIG_PM_DEBUG */
+
+/**
+ * platform_begin - Call platform to start hibernation.
+ * @platform_mode: Whether or not to use the platform driver.
+ */
+static int platform_begin(int platform_mode)
+{
+	return (platform_mode && hibernation_ops) ?
+		hibernation_ops->begin(PMSG_FREEZE) : 0;
+}
+
+/**
+ * platform_end - Call platform to finish transition to the working state.
+ * @platform_mode: Whether or not to use the platform driver.
+ */
+static void platform_end(int platform_mode)
+{
+	if (platform_mode && hibernation_ops)
+		hibernation_ops->end();
+}
+
+/**
+ * platform_pre_snapshot - Call platform to prepare the machine for hibernation.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Use the platform driver to prepare the system for creating a hibernate image,
+ * if so configured, and return an error code if that fails.
+ */
+
+static int platform_pre_snapshot(int platform_mode)
+{
+	return (platform_mode && hibernation_ops) ?
+		hibernation_ops->pre_snapshot() : 0;
+}
+
+/**
+ * platform_leave - Call platform to prepare a transition to the working state.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Use the platform driver prepare to prepare the machine for switching to the
+ * normal mode of operation.
+ *
+ * This routine is called on one CPU with interrupts disabled.
+ */
+static void platform_leave(int platform_mode)
+{
+	if (platform_mode && hibernation_ops)
+		hibernation_ops->leave();
+}
+
+/**
+ * platform_finish - Call platform to switch the system to the working state.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Use the platform driver to switch the machine to the normal mode of
+ * operation.
+ *
+ * This routine must be called after platform_prepare().
+ */
+static void platform_finish(int platform_mode)
+{
+	if (platform_mode && hibernation_ops)
+		hibernation_ops->finish();
+}
+
+/**
+ * platform_pre_restore - Prepare for hibernate image restoration.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Use the platform driver to prepare the system for resume from a hibernation
+ * image.
+ *
+ * If the restore fails after this function has been called,
+ * platform_restore_cleanup() must be called.
+ */
+static int platform_pre_restore(int platform_mode)
+{
+	return (platform_mode && hibernation_ops) ?
+		hibernation_ops->pre_restore() : 0;
+}
+
+/**
+ * platform_restore_cleanup - Switch to the working state after failing restore.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Use the platform driver to switch the system to the normal mode of operation
+ * after a failing restore.
+ *
+ * If platform_pre_restore() has been called before the failing restore, this
+ * function must be called too, regardless of the result of
+ * platform_pre_restore().
+ */
+static void platform_restore_cleanup(int platform_mode)
+{
+	if (platform_mode && hibernation_ops)
+		hibernation_ops->restore_cleanup();
+}
+
+/**
+ * platform_recover - Recover from a failure to suspend devices.
+ * @platform_mode: Whether or not to use the platform driver.
+ */
+static void platform_recover(int platform_mode)
+{
+	if (platform_mode && hibernation_ops && hibernation_ops->recover)
+		hibernation_ops->recover();
+}
+
+/**
+ * swsusp_show_speed - Print time elapsed between two events during hibernation.
+ * @start: Starting event.
+ * @stop: Final event.
+ * @nr_pages: Number of memory pages processed between @start and @stop.
+ * @msg: Additional diagnostic message to print.
+ */
+void swsusp_show_speed(ktime_t start, ktime_t stop,
+		      unsigned nr_pages, char *msg)
+{
+	ktime_t diff;
+	u64 elapsed_centisecs64;
+	unsigned int centisecs;
+	unsigned int k;
+	unsigned int kps;
+
+	diff = ktime_sub(stop, start);
+	elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
+	centisecs = elapsed_centisecs64;
+	if (centisecs == 0)
+		centisecs = 1;	/* avoid div-by-zero */
+	k = nr_pages * (PAGE_SIZE / 1024);
+	kps = (k * 100) / centisecs;
+	pr_info("%s %u kbytes in %u.%02u seconds (%u.%02u MB/s)\n",
+		msg, k, centisecs / 100, centisecs % 100, kps / 1000,
+		(kps % 1000) / 10);
+}
+
+__weak int arch_resume_nosmt(void)
+{
+	return 0;
+}
+
+/**
+ * create_image - Create a hibernation image.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Execute device drivers' "late" and "noirq" freeze callbacks, create a
+ * hibernation image and run the drivers' "noirq" and "early" thaw callbacks.
+ *
+ * Control reappears in this routine after the subsequent restore.
+ */
+static int create_image(int platform_mode)
+{
+	int error;
+
+	error = dpm_suspend_end(PMSG_FREEZE);
+	if (error) {
+		pr_err("Some devices failed to power down, aborting\n");
+		return error;
+	}
+
+	error = platform_pre_snapshot(platform_mode);
+	if (error || hibernation_test(TEST_PLATFORM))
+		goto Platform_finish;
+
+	error = pm_sleep_disable_secondary_cpus();
+	if (error || hibernation_test(TEST_CPUS))
+		goto Enable_cpus;
+
+	local_irq_disable();
+
+	system_state = SYSTEM_SUSPEND;
+
+	error = syscore_suspend();
+	if (error) {
+		pr_err("Some system devices failed to power down, aborting\n");
+		goto Enable_irqs;
+	}
+
+	if (hibernation_test(TEST_CORE) || pm_wakeup_pending())
+		goto Power_up;
+
+	in_suspend = 1;
+	save_processor_state();
+	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true);
+	error = swsusp_arch_suspend();
+	/* Restore control flow magically appears here */
+	restore_processor_state();
+	trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false);
+	if (error)
+		pr_err("Error %d creating image\n", error);
+
+	if (!in_suspend) {
+		events_check_enabled = false;
+		clear_or_poison_free_pages();
+	}
+
+	platform_leave(platform_mode);
+
+ Power_up:
+	syscore_resume();
+
+ Enable_irqs:
+	system_state = SYSTEM_RUNNING;
+	local_irq_enable();
+
+ Enable_cpus:
+	pm_sleep_enable_secondary_cpus();
+
+	/* Allow architectures to do nosmt-specific post-resume dances */
+	if (!in_suspend)
+		error = arch_resume_nosmt();
+
+ Platform_finish:
+	platform_finish(platform_mode);
+
+	dpm_resume_start(in_suspend ?
+		(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
+
+	return error;
+}
+
+/**
+ * hibernation_snapshot - Quiesce devices and create a hibernation image.
+ * @platform_mode: If set, use platform driver to prepare for the transition.
+ *
+ * This routine must be called with system_transition_mutex held.
+ */
+int hibernation_snapshot(int platform_mode)
+{
+	pm_message_t msg;
+	int error;
+
+	pm_suspend_clear_flags();
+	error = platform_begin(platform_mode);
+	if (error)
+		goto Close;
+
+	/* Preallocate image memory before shutting down devices. */
+	error = hibernate_preallocate_memory();
+	if (error)
+		goto Close;
+
+	error = freeze_kernel_threads();
+	if (error)
+		goto Cleanup;
+
+	if (hibernation_test(TEST_FREEZER)) {
+
+		/*
+		 * Indicate to the caller that we are returning due to a
+		 * successful freezer test.
+		 */
+		freezer_test_done = true;
+		goto Thaw;
+	}
+
+	error = dpm_prepare(PMSG_FREEZE);
+	if (error) {
+		dpm_complete(PMSG_RECOVER);
+		goto Thaw;
+	}
+
+	suspend_console();
+	pm_restrict_gfp_mask();
+
+	error = dpm_suspend(PMSG_FREEZE);
+
+	if (error || hibernation_test(TEST_DEVICES))
+		platform_recover(platform_mode);
+	else
+		error = create_image(platform_mode);
+
+	/*
+	 * In the case that we call create_image() above, the control
+	 * returns here (1) after the image has been created or the
+	 * image creation has failed and (2) after a successful restore.
+	 */
+
+	/* We may need to release the preallocated image pages here. */
+	if (error || !in_suspend)
+		swsusp_free();
+
+	msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
+	dpm_resume(msg);
+
+	if (error || !in_suspend)
+		pm_restore_gfp_mask();
+
+	resume_console();
+	dpm_complete(msg);
+
+ Close:
+	platform_end(platform_mode);
+	return error;
+
+ Thaw:
+	thaw_kernel_threads();
+ Cleanup:
+	swsusp_free();
+	goto Close;
+}
+
+int __weak hibernate_resume_nonboot_cpu_disable(void)
+{
+	return suspend_disable_secondary_cpus();
+}
+
+/**
+ * resume_target_kernel - Restore system state from a hibernation image.
+ * @platform_mode: Whether or not to use the platform driver.
+ *
+ * Execute device drivers' "noirq" and "late" freeze callbacks, restore the
+ * contents of highmem that have not been restored yet from the image and run
+ * the low-level code that will restore the remaining contents of memory and
+ * switch to the just restored target kernel.
+ */
+static int resume_target_kernel(bool platform_mode)
+{
+	int error;
+
+	error = dpm_suspend_end(PMSG_QUIESCE);
+	if (error) {
+		pr_err("Some devices failed to power down, aborting resume\n");
+		return error;
+	}
+
+	error = platform_pre_restore(platform_mode);
+	if (error)
+		goto Cleanup;
+
+	cpuidle_pause();
+
+	error = hibernate_resume_nonboot_cpu_disable();
+	if (error)
+		goto Enable_cpus;
+
+	local_irq_disable();
+	system_state = SYSTEM_SUSPEND;
+
+	error = syscore_suspend();
+	if (error)
+		goto Enable_irqs;
+
+	save_processor_state();
+	error = restore_highmem();
+	if (!error) {
+		error = swsusp_arch_resume();
+		/*
+		 * The code below is only ever reached in case of a failure.
+		 * Otherwise, execution continues at the place where
+		 * swsusp_arch_suspend() was called.
+		 */
+		BUG_ON(!error);
+		/*
+		 * This call to restore_highmem() reverts the changes made by
+		 * the previous one.
+		 */
+		restore_highmem();
+	}
+	/*
+	 * The only reason why swsusp_arch_resume() can fail is memory being
+	 * very tight, so we have to free it as soon as we can to avoid
+	 * subsequent failures.
+	 */
+	swsusp_free();
+	restore_processor_state();
+	touch_softlockup_watchdog();
+
+	syscore_resume();
+
+ Enable_irqs:
+	system_state = SYSTEM_RUNNING;
+	local_irq_enable();
+
+ Enable_cpus:
+	pm_sleep_enable_secondary_cpus();
+
+ Cleanup:
+	platform_restore_cleanup(platform_mode);
+
+	dpm_resume_start(PMSG_RECOVER);
+
+	return error;
+}
+
+/**
+ * hibernation_restore - Quiesce devices and restore from a hibernation image.
+ * @platform_mode: If set, use platform driver to prepare for the transition.
+ *
+ * This routine must be called with system_transition_mutex held.  If it is
+ * successful, control reappears in the restored target kernel in
+ * hibernation_snapshot().
+ */
+int hibernation_restore(int platform_mode)
+{
+	int error;
+
+	pm_prepare_console();
+	suspend_console();
+	pm_restrict_gfp_mask();
+	error = dpm_suspend_start(PMSG_QUIESCE);
+	if (!error) {
+		error = resume_target_kernel(platform_mode);
+		/*
+		 * The above should either succeed and jump to the new kernel,
+		 * or return with an error. Otherwise things are just
+		 * undefined, so let's be paranoid.
+		 */
+		BUG_ON(!error);
+	}
+	dpm_resume_end(PMSG_RECOVER);
+	pm_restore_gfp_mask();
+	resume_console();
+	pm_restore_console();
+	return error;
+}
+
+/**
+ * hibernation_platform_enter - Power off the system using the platform driver.
+ */
+int hibernation_platform_enter(void)
+{
+	int error;
+
+	if (!hibernation_ops)
+		return -ENOSYS;
+
+	/*
+	 * We have cancelled the power transition by running
+	 * hibernation_ops->finish() before saving the image, so we should let
+	 * the firmware know that we're going to enter the sleep state after all
+	 */
+	error = hibernation_ops->begin(PMSG_HIBERNATE);
+	if (error)
+		goto Close;
+
+	entering_platform_hibernation = true;
+	suspend_console();
+	error = dpm_suspend_start(PMSG_HIBERNATE);
+	if (error) {
+		if (hibernation_ops->recover)
+			hibernation_ops->recover();
+		goto Resume_devices;
+	}
+
+	error = dpm_suspend_end(PMSG_HIBERNATE);
+	if (error)
+		goto Resume_devices;
+
+	error = hibernation_ops->prepare();
+	if (error)
+		goto Platform_finish;
+
+	error = pm_sleep_disable_secondary_cpus();
+	if (error)
+		goto Enable_cpus;
+
+	local_irq_disable();
+	system_state = SYSTEM_SUSPEND;
+	syscore_suspend();
+	if (pm_wakeup_pending()) {
+		error = -EAGAIN;
+		goto Power_up;
+	}
+
+	hibernation_ops->enter();
+	/* We should never get here */
+	while (1);
+
+ Power_up:
+	syscore_resume();
+	system_state = SYSTEM_RUNNING;
+	local_irq_enable();
+
+ Enable_cpus:
+	pm_sleep_enable_secondary_cpus();
+
+ Platform_finish:
+	hibernation_ops->finish();
+
+	dpm_resume_start(PMSG_RESTORE);
+
+ Resume_devices:
+	entering_platform_hibernation = false;
+	dpm_resume_end(PMSG_RESTORE);
+	resume_console();
+
+ Close:
+	hibernation_ops->end();
+
+	return error;
+}
+
+/**
+ * power_down - Shut the machine down for hibernation.
+ *
+ * Use the platform driver, if configured, to put the system into the sleep
+ * state corresponding to hibernation, or try to power it off or reboot,
+ * depending on the value of hibernation_mode.
+ */
+static void power_down(void)
+{
+#ifdef CONFIG_SUSPEND
+	int error;
+
+	if (hibernation_mode == HIBERNATION_SUSPEND) {
+		error = suspend_devices_and_enter(mem_sleep_current);
+		if (error) {
+			hibernation_mode = hibernation_ops ?
+						HIBERNATION_PLATFORM :
+						HIBERNATION_SHUTDOWN;
+		} else {
+			/* Restore swap signature. */
+			error = swsusp_unmark();
+			if (error)
+				pr_err("Swap will be unusable! Try swapon -a.\n");
+
+			return;
+		}
+	}
+#endif
+
+	switch (hibernation_mode) {
+	case HIBERNATION_REBOOT:
+		kernel_restart(NULL);
+		break;
+	case HIBERNATION_PLATFORM:
+		hibernation_platform_enter();
+		fallthrough;
+	case HIBERNATION_SHUTDOWN:
+		if (kernel_can_power_off())
+			kernel_power_off();
+		break;
+	}
+	kernel_halt();
+	/*
+	 * Valid image is on the disk, if we continue we risk serious data
+	 * corruption after resume.
+	 */
+	pr_crit("Power down manually\n");
+	while (1)
+		cpu_relax();
+}
+
+static int load_image_and_restore(void)
+{
+	int error;
+	unsigned int flags;
+	fmode_t mode = FMODE_READ;
+
+	if (snapshot_test)
+		mode |= FMODE_EXCL;
+
+	pm_pr_dbg("Loading hibernation image.\n");
+
+	lock_device_hotplug();
+	error = create_basic_memory_bitmaps();
+	if (error) {
+		swsusp_close(mode);
+		goto Unlock;
+	}
+
+	error = swsusp_read(&flags);
+	swsusp_close(mode);
+	if (!error)
+		error = hibernation_restore(flags & SF_PLATFORM_MODE);
+
+	pr_err("Failed to load image, recovering.\n");
+	swsusp_free();
+	free_basic_memory_bitmaps();
+ Unlock:
+	unlock_device_hotplug();
+
+	return error;
+}
+
+/**
+ * hibernate - Carry out system hibernation, including saving the image.
+ */
+int hibernate(void)
+{
+	unsigned int sleep_flags;
+	int error;
+
+	if (!hibernation_available()) {
+		pm_pr_dbg("Hibernation not available.\n");
+		return -EPERM;
+	}
+
+	sleep_flags = lock_system_sleep();
+	/* The snapshot device should not be opened while we're running */
+	if (!hibernate_acquire()) {
+		error = -EBUSY;
+		goto Unlock;
+	}
+
+	pr_info("hibernation entry\n");
+	pm_prepare_console();
+	error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
+	if (error)
+		goto Restore;
+
+	ksys_sync_helper();
+
+	error = freeze_processes();
+	if (error)
+		goto Exit;
+
+	/* protected by system_transition_mutex */
+	snapshot_test = false;
+
+	lock_device_hotplug();
+	/* Allocate memory management structures */
+	error = create_basic_memory_bitmaps();
+	if (error)
+		goto Thaw;
+
+	error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
+	if (error || freezer_test_done)
+		goto Free_bitmaps;
+
+	if (in_suspend) {
+		unsigned int flags = 0;
+
+		if (hibernation_mode == HIBERNATION_PLATFORM)
+			flags |= SF_PLATFORM_MODE;
+		if (nocompress)
+			flags |= SF_NOCOMPRESS_MODE;
+		else
+		        flags |= SF_CRC32_MODE;
+
+		pm_pr_dbg("Writing hibernation image.\n");
+		error = swsusp_write(flags);
+		swsusp_free();
+		if (!error) {
+			if (hibernation_mode == HIBERNATION_TEST_RESUME)
+				snapshot_test = true;
+			else
+				power_down();
+		}
+		in_suspend = 0;
+		pm_restore_gfp_mask();
+	} else {
+		pm_pr_dbg("Hibernation image restored successfully.\n");
+	}
+
+ Free_bitmaps:
+	free_basic_memory_bitmaps();
+ Thaw:
+	unlock_device_hotplug();
+	if (snapshot_test) {
+		pm_pr_dbg("Checking hibernation image\n");
+		error = swsusp_check();
+		if (!error)
+			error = load_image_and_restore();
+	}
+	thaw_processes();
+
+	/* Don't bother checking whether freezer_test_done is true */
+	freezer_test_done = false;
+ Exit:
+	pm_notifier_call_chain(PM_POST_HIBERNATION);
+ Restore:
+	pm_restore_console();
+	hibernate_release();
+ Unlock:
+	unlock_system_sleep(sleep_flags);
+	pr_info("hibernation exit\n");
+
+	return error;
+}
+
+/**
+ * hibernate_quiet_exec - Execute a function with all devices frozen.
+ * @func: Function to execute.
+ * @data: Data pointer to pass to @func.
+ *
+ * Return the @func return value or an error code if it cannot be executed.
+ */
+int hibernate_quiet_exec(int (*func)(void *data), void *data)
+{
+	unsigned int sleep_flags;
+	int error;
+
+	sleep_flags = lock_system_sleep();
+
+	if (!hibernate_acquire()) {
+		error = -EBUSY;
+		goto unlock;
+	}
+
+	pm_prepare_console();
+
+	error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
+	if (error)
+		goto restore;
+
+	error = freeze_processes();
+	if (error)
+		goto exit;
+
+	lock_device_hotplug();
+
+	pm_suspend_clear_flags();
+
+	error = platform_begin(true);
+	if (error)
+		goto thaw;
+
+	error = freeze_kernel_threads();
+	if (error)
+		goto thaw;
+
+	error = dpm_prepare(PMSG_FREEZE);
+	if (error)
+		goto dpm_complete;
+
+	suspend_console();
+
+	error = dpm_suspend(PMSG_FREEZE);
+	if (error)
+		goto dpm_resume;
+
+	error = dpm_suspend_end(PMSG_FREEZE);
+	if (error)
+		goto dpm_resume;
+
+	error = platform_pre_snapshot(true);
+	if (error)
+		goto skip;
+
+	error = func(data);
+
+skip:
+	platform_finish(true);
+
+	dpm_resume_start(PMSG_THAW);
+
+dpm_resume:
+	dpm_resume(PMSG_THAW);
+
+	resume_console();
+
+dpm_complete:
+	dpm_complete(PMSG_THAW);
+
+	thaw_kernel_threads();
+
+thaw:
+	platform_end(true);
+
+	unlock_device_hotplug();
+
+	thaw_processes();
+
+exit:
+	pm_notifier_call_chain(PM_POST_HIBERNATION);
+
+restore:
+	pm_restore_console();
+
+	hibernate_release();
+
+unlock:
+	unlock_system_sleep(sleep_flags);
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(hibernate_quiet_exec);
+
+/**
+ * software_resume - Resume from a saved hibernation image.
+ *
+ * This routine is called as a late initcall, when all devices have been
+ * discovered and initialized already.
+ *
+ * The image reading code is called to see if there is a hibernation image
+ * available for reading.  If that is the case, devices are quiesced and the
+ * contents of memory is restored from the saved image.
+ *
+ * If this is successful, control reappears in the restored target kernel in
+ * hibernation_snapshot() which returns to hibernate().  Otherwise, the routine
+ * attempts to recover gracefully and make the kernel return to the normal mode
+ * of operation.
+ */
+static int software_resume(void)
+{
+	int error;
+
+	/*
+	 * If the user said "noresume".. bail out early.
+	 */
+	if (noresume || !hibernation_available())
+		return 0;
+
+	/*
+	 * name_to_dev_t() below takes a sysfs buffer mutex when sysfs
+	 * is configured into the kernel. Since the regular hibernate
+	 * trigger path is via sysfs which takes a buffer mutex before
+	 * calling hibernate functions (which take system_transition_mutex)
+	 * this can cause lockdep to complain about a possible ABBA deadlock
+	 * which cannot happen since we're in the boot code here and
+	 * sysfs can't be invoked yet. Therefore, we use a subclass
+	 * here to avoid lockdep complaining.
+	 */
+	mutex_lock_nested(&system_transition_mutex, SINGLE_DEPTH_NESTING);
+
+	snapshot_test = false;
+
+	if (swsusp_resume_device)
+		goto Check_image;
+
+	if (!strlen(resume_file)) {
+		error = -ENOENT;
+		goto Unlock;
+	}
+
+	pm_pr_dbg("Checking hibernation image partition %s\n", resume_file);
+
+	if (resume_delay) {
+		pr_info("Waiting %dsec before reading resume device ...\n",
+			resume_delay);
+		ssleep(resume_delay);
+	}
+
+	/* Check if the device is there */
+	swsusp_resume_device = name_to_dev_t(resume_file);
+	if (!swsusp_resume_device) {
+		/*
+		 * Some device discovery might still be in progress; we need
+		 * to wait for this to finish.
+		 */
+		wait_for_device_probe();
+
+		if (resume_wait) {
+			while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
+				msleep(10);
+			async_synchronize_full();
+		}
+
+		swsusp_resume_device = name_to_dev_t(resume_file);
+		if (!swsusp_resume_device) {
+			error = -ENODEV;
+			goto Unlock;
+		}
+	}
+
+ Check_image:
+	pm_pr_dbg("Hibernation image partition %d:%d present\n",
+		MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
+
+	pm_pr_dbg("Looking for hibernation image.\n");
+	error = swsusp_check();
+	if (error)
+		goto Unlock;
+
+	/* The snapshot device should not be opened while we're running */
+	if (!hibernate_acquire()) {
+		error = -EBUSY;
+		swsusp_close(FMODE_READ | FMODE_EXCL);
+		goto Unlock;
+	}
+
+	pr_info("resume from hibernation\n");
+	pm_prepare_console();
+	error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE);
+	if (error)
+		goto Restore;
+
+	pm_pr_dbg("Preparing processes for hibernation restore.\n");
+	error = freeze_processes();
+	if (error)
+		goto Close_Finish;
+
+	error = freeze_kernel_threads();
+	if (error) {
+		thaw_processes();
+		goto Close_Finish;
+	}
+
+	error = load_image_and_restore();
+	thaw_processes();
+ Finish:
+	pm_notifier_call_chain(PM_POST_RESTORE);
+ Restore:
+	pm_restore_console();
+	pr_info("resume failed (%d)\n", error);
+	hibernate_release();
+	/* For success case, the suspend path will release the lock */
+ Unlock:
+	mutex_unlock(&system_transition_mutex);
+	pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
+	return error;
+ Close_Finish:
+	swsusp_close(FMODE_READ | FMODE_EXCL);
+	goto Finish;
+}
+
+late_initcall_sync(software_resume);
+
+
+static const char * const hibernation_modes[] = {
+	[HIBERNATION_PLATFORM]	= "platform",
+	[HIBERNATION_SHUTDOWN]	= "shutdown",
+	[HIBERNATION_REBOOT]	= "reboot",
+#ifdef CONFIG_SUSPEND
+	[HIBERNATION_SUSPEND]	= "suspend",
+#endif
+	[HIBERNATION_TEST_RESUME]	= "test_resume",
+};
+
+/*
+ * /sys/power/disk - Control hibernation mode.
+ *
+ * Hibernation can be handled in several ways.  There are a few different ways
+ * to put the system into the sleep state: using the platform driver (e.g. ACPI
+ * or other hibernation_ops), powering it off or rebooting it (for testing
+ * mostly).
+ *
+ * The sysfs file /sys/power/disk provides an interface for selecting the
+ * hibernation mode to use.  Reading from this file causes the available modes
+ * to be printed.  There are 3 modes that can be supported:
+ *
+ *	'platform'
+ *	'shutdown'
+ *	'reboot'
+ *
+ * If a platform hibernation driver is in use, 'platform' will be supported
+ * and will be used by default.  Otherwise, 'shutdown' will be used by default.
+ * The selected option (i.e. the one corresponding to the current value of
+ * hibernation_mode) is enclosed by a square bracket.
+ *
+ * To select a given hibernation mode it is necessary to write the mode's
+ * string representation (as returned by reading from /sys/power/disk) back
+ * into /sys/power/disk.
+ */
+
+static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
+			 char *buf)
+{
+	int i;
+	char *start = buf;
+
+	if (!hibernation_available())
+		return sprintf(buf, "[disabled]\n");
+
+	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
+		if (!hibernation_modes[i])
+			continue;
+		switch (i) {
+		case HIBERNATION_SHUTDOWN:
+		case HIBERNATION_REBOOT:
+#ifdef CONFIG_SUSPEND
+		case HIBERNATION_SUSPEND:
+#endif
+		case HIBERNATION_TEST_RESUME:
+			break;
+		case HIBERNATION_PLATFORM:
+			if (hibernation_ops)
+				break;
+			/* not a valid mode, continue with loop */
+			continue;
+		}
+		if (i == hibernation_mode)
+			buf += sprintf(buf, "[%s] ", hibernation_modes[i]);
+		else
+			buf += sprintf(buf, "%s ", hibernation_modes[i]);
+	}
+	buf += sprintf(buf, "\n");
+	return buf-start;
+}
+
+static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
+			  const char *buf, size_t n)
+{
+	int mode = HIBERNATION_INVALID;
+	unsigned int sleep_flags;
+	int error = 0;
+	int len;
+	char *p;
+	int i;
+
+	if (!hibernation_available())
+		return -EPERM;
+
+	p = memchr(buf, '\n', n);
+	len = p ? p - buf : n;
+
+	sleep_flags = lock_system_sleep();
+	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
+		if (len == strlen(hibernation_modes[i])
+		    && !strncmp(buf, hibernation_modes[i], len)) {
+			mode = i;
+			break;
+		}
+	}
+	if (mode != HIBERNATION_INVALID) {
+		switch (mode) {
+		case HIBERNATION_SHUTDOWN:
+		case HIBERNATION_REBOOT:
+#ifdef CONFIG_SUSPEND
+		case HIBERNATION_SUSPEND:
+#endif
+		case HIBERNATION_TEST_RESUME:
+			hibernation_mode = mode;
+			break;
+		case HIBERNATION_PLATFORM:
+			if (hibernation_ops)
+				hibernation_mode = mode;
+			else
+				error = -EINVAL;
+		}
+	} else
+		error = -EINVAL;
+
+	if (!error)
+		pm_pr_dbg("Hibernation mode set to '%s'\n",
+			       hibernation_modes[mode]);
+	unlock_system_sleep(sleep_flags);
+	return error ? error : n;
+}
+
+power_attr(disk);
+
+static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr,
+			   char *buf)
+{
+	return sprintf(buf, "%d:%d\n", MAJOR(swsusp_resume_device),
+		       MINOR(swsusp_resume_device));
+}
+
+static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
+			    const char *buf, size_t n)
+{
+	unsigned int sleep_flags;
+	int len = n;
+	char *name;
+	dev_t res;
+
+	if (len && buf[len-1] == '\n')
+		len--;
+	name = kstrndup(buf, len, GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+
+	res = name_to_dev_t(name);
+	kfree(name);
+	if (!res)
+		return -EINVAL;
+
+	sleep_flags = lock_system_sleep();
+	swsusp_resume_device = res;
+	unlock_system_sleep(sleep_flags);
+
+	pm_pr_dbg("Configured hibernation resume from disk to %u\n",
+		  swsusp_resume_device);
+	noresume = 0;
+	software_resume();
+	return n;
+}
+
+power_attr(resume);
+
+static ssize_t resume_offset_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%llu\n", (unsigned long long)swsusp_resume_block);
+}
+
+static ssize_t resume_offset_store(struct kobject *kobj,
+				   struct kobj_attribute *attr, const char *buf,
+				   size_t n)
+{
+	unsigned long long offset;
+	int rc;
+
+	rc = kstrtoull(buf, 0, &offset);
+	if (rc)
+		return rc;
+	swsusp_resume_block = offset;
+
+	return n;
+}
+
+power_attr(resume_offset);
+
+static ssize_t image_size_show(struct kobject *kobj, struct kobj_attribute *attr,
+			       char *buf)
+{
+	return sprintf(buf, "%lu\n", image_size);
+}
+
+static ssize_t image_size_store(struct kobject *kobj, struct kobj_attribute *attr,
+				const char *buf, size_t n)
+{
+	unsigned long size;
+
+	if (sscanf(buf, "%lu", &size) == 1) {
+		image_size = size;
+		return n;
+	}
+
+	return -EINVAL;
+}
+
+power_attr(image_size);
+
+static ssize_t reserved_size_show(struct kobject *kobj,
+				  struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%lu\n", reserved_size);
+}
+
+static ssize_t reserved_size_store(struct kobject *kobj,
+				   struct kobj_attribute *attr,
+				   const char *buf, size_t n)
+{
+	unsigned long size;
+
+	if (sscanf(buf, "%lu", &size) == 1) {
+		reserved_size = size;
+		return n;
+	}
+
+	return -EINVAL;
+}
+
+power_attr(reserved_size);
+
+static struct attribute *g[] = {
+	&disk_attr.attr,
+	&resume_offset_attr.attr,
+	&resume_attr.attr,
+	&image_size_attr.attr,
+	&reserved_size_attr.attr,
+	NULL,
+};
+
+
+static const struct attribute_group attr_group = {
+	.attrs = g,
+};
+
+
+static int __init pm_disk_init(void)
+{
+	return sysfs_create_group(power_kobj, &attr_group);
+}
+
+core_initcall(pm_disk_init);
+
+
+static int __init resume_setup(char *str)
+{
+	if (noresume)
+		return 1;
+
+	strncpy(resume_file, str, 255);
+	return 1;
+}
+
+static int __init resume_offset_setup(char *str)
+{
+	unsigned long long offset;
+
+	if (noresume)
+		return 1;
+
+	if (sscanf(str, "%llu", &offset) == 1)
+		swsusp_resume_block = offset;
+
+	return 1;
+}
+
+static int __init hibernate_setup(char *str)
+{
+	if (!strncmp(str, "noresume", 8)) {
+		noresume = 1;
+	} else if (!strncmp(str, "nocompress", 10)) {
+		nocompress = 1;
+	} else if (!strncmp(str, "no", 2)) {
+		noresume = 1;
+		nohibernate = 1;
+	} else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
+		   && !strncmp(str, "protect_image", 13)) {
+		enable_restore_image_protection();
+	}
+	return 1;
+}
+
+static int __init noresume_setup(char *str)
+{
+	noresume = 1;
+	return 1;
+}
+
+static int __init resumewait_setup(char *str)
+{
+	resume_wait = 1;
+	return 1;
+}
+
+static int __init resumedelay_setup(char *str)
+{
+	int rc = kstrtouint(str, 0, &resume_delay);
+
+	if (rc)
+		pr_warn("resumedelay: bad option string '%s'\n", str);
+	return 1;
+}
+
+static int __init nohibernate_setup(char *str)
+{
+	noresume = 1;
+	nohibernate = 1;
+	return 1;
+}
+
+__setup("noresume", noresume_setup);
+__setup("resume_offset=", resume_offset_setup);
+__setup("resume=", resume_setup);
+__setup("hibernate=", hibernate_setup);
+__setup("resumewait", resumewait_setup);
+__setup("resumedelay=", resumedelay_setup);
+__setup("nohibernate", nohibernate_setup);
diff --git a/kernel/power/main.c b/kernel/power/main.c
new file mode 100644
index 000000000..31ec4a9b9
--- /dev/null
+++ b/kernel/power/main.c
@@ -0,0 +1,940 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/power/main.c - PM subsystem core functionality.
+ *
+ * Copyright (c) 2003 Patrick Mochel
+ * Copyright (c) 2003 Open Source Development Lab
+ */
+
+#include <linux/export.h>
+#include <linux/kobject.h>
+#include <linux/string.h>
+#include <linux/pm-trace.h>
+#include <linux/workqueue.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/suspend.h>
+#include <linux/syscalls.h>
+#include <linux/pm_runtime.h>
+
+#include "power.h"
+
+#ifdef CONFIG_PM_SLEEP
+
+unsigned int lock_system_sleep(void)
+{
+	unsigned int flags = current->flags;
+	current->flags |= PF_NOFREEZE;
+	mutex_lock(&system_transition_mutex);
+	return flags;
+}
+EXPORT_SYMBOL_GPL(lock_system_sleep);
+
+void unlock_system_sleep(unsigned int flags)
+{
+	/*
+	 * Don't use freezer_count() because we don't want the call to
+	 * try_to_freeze() here.
+	 *
+	 * Reason:
+	 * Fundamentally, we just don't need it, because freezing condition
+	 * doesn't come into effect until we release the
+	 * system_transition_mutex lock, since the freezer always works with
+	 * system_transition_mutex held.
+	 *
+	 * More importantly, in the case of hibernation,
+	 * unlock_system_sleep() gets called in snapshot_read() and
+	 * snapshot_write() when the freezing condition is still in effect.
+	 * Which means, if we use try_to_freeze() here, it would make them
+	 * enter the refrigerator, thus causing hibernation to lockup.
+	 */
+	if (!(flags & PF_NOFREEZE))
+		current->flags &= ~PF_NOFREEZE;
+	mutex_unlock(&system_transition_mutex);
+}
+EXPORT_SYMBOL_GPL(unlock_system_sleep);
+
+void ksys_sync_helper(void)
+{
+	ktime_t start;
+	long elapsed_msecs;
+
+	start = ktime_get();
+	ksys_sync();
+	elapsed_msecs = ktime_to_ms(ktime_sub(ktime_get(), start));
+	pr_info("Filesystems sync: %ld.%03ld seconds\n",
+		elapsed_msecs / MSEC_PER_SEC, elapsed_msecs % MSEC_PER_SEC);
+}
+EXPORT_SYMBOL_GPL(ksys_sync_helper);
+
+/* Routines for PM-transition notifications */
+
+static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
+
+int register_pm_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&pm_chain_head, nb);
+}
+EXPORT_SYMBOL_GPL(register_pm_notifier);
+
+int unregister_pm_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&pm_chain_head, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_pm_notifier);
+
+int pm_notifier_call_chain_robust(unsigned long val_up, unsigned long val_down)
+{
+	int ret;
+
+	ret = blocking_notifier_call_chain_robust(&pm_chain_head, val_up, val_down, NULL);
+
+	return notifier_to_errno(ret);
+}
+
+int pm_notifier_call_chain(unsigned long val)
+{
+	return blocking_notifier_call_chain(&pm_chain_head, val, NULL);
+}
+
+/* If set, devices may be suspended and resumed asynchronously. */
+int pm_async_enabled = 1;
+
+static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
+			     char *buf)
+{
+	return sprintf(buf, "%d\n", pm_async_enabled);
+}
+
+static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
+			      const char *buf, size_t n)
+{
+	unsigned long val;
+
+	if (kstrtoul(buf, 10, &val))
+		return -EINVAL;
+
+	if (val > 1)
+		return -EINVAL;
+
+	pm_async_enabled = val;
+	return n;
+}
+
+power_attr(pm_async);
+
+#ifdef CONFIG_SUSPEND
+static ssize_t mem_sleep_show(struct kobject *kobj, struct kobj_attribute *attr,
+			      char *buf)
+{
+	char *s = buf;
+	suspend_state_t i;
+
+	for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++) {
+		if (i >= PM_SUSPEND_MEM && cxl_mem_active())
+			continue;
+		if (mem_sleep_states[i]) {
+			const char *label = mem_sleep_states[i];
+
+			if (mem_sleep_current == i)
+				s += sprintf(s, "[%s] ", label);
+			else
+				s += sprintf(s, "%s ", label);
+		}
+	}
+
+	/* Convert the last space to a newline if needed. */
+	if (s != buf)
+		*(s-1) = '\n';
+
+	return (s - buf);
+}
+
+static suspend_state_t decode_suspend_state(const char *buf, size_t n)
+{
+	suspend_state_t state;
+	char *p;
+	int len;
+
+	p = memchr(buf, '\n', n);
+	len = p ? p - buf : n;
+
+	for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
+		const char *label = mem_sleep_states[state];
+
+		if (label && len == strlen(label) && !strncmp(buf, label, len))
+			return state;
+	}
+
+	return PM_SUSPEND_ON;
+}
+
+static ssize_t mem_sleep_store(struct kobject *kobj, struct kobj_attribute *attr,
+			       const char *buf, size_t n)
+{
+	suspend_state_t state;
+	int error;
+
+	error = pm_autosleep_lock();
+	if (error)
+		return error;
+
+	if (pm_autosleep_state() > PM_SUSPEND_ON) {
+		error = -EBUSY;
+		goto out;
+	}
+
+	state = decode_suspend_state(buf, n);
+	if (state < PM_SUSPEND_MAX && state > PM_SUSPEND_ON)
+		mem_sleep_current = state;
+	else
+		error = -EINVAL;
+
+ out:
+	pm_autosleep_unlock();
+	return error ? error : n;
+}
+
+power_attr(mem_sleep);
+
+/*
+ * sync_on_suspend: invoke ksys_sync_helper() before suspend.
+ *
+ * show() returns whether ksys_sync_helper() is invoked before suspend.
+ * store() accepts 0 or 1.  0 disables ksys_sync_helper() and 1 enables it.
+ */
+bool sync_on_suspend_enabled = !IS_ENABLED(CONFIG_SUSPEND_SKIP_SYNC);
+
+static ssize_t sync_on_suspend_show(struct kobject *kobj,
+				   struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", sync_on_suspend_enabled);
+}
+
+static ssize_t sync_on_suspend_store(struct kobject *kobj,
+				    struct kobj_attribute *attr,
+				    const char *buf, size_t n)
+{
+	unsigned long val;
+
+	if (kstrtoul(buf, 10, &val))
+		return -EINVAL;
+
+	if (val > 1)
+		return -EINVAL;
+
+	sync_on_suspend_enabled = !!val;
+	return n;
+}
+
+power_attr(sync_on_suspend);
+#endif /* CONFIG_SUSPEND */
+
+#ifdef CONFIG_PM_SLEEP_DEBUG
+int pm_test_level = TEST_NONE;
+
+static const char * const pm_tests[__TEST_AFTER_LAST] = {
+	[TEST_NONE] = "none",
+	[TEST_CORE] = "core",
+	[TEST_CPUS] = "processors",
+	[TEST_PLATFORM] = "platform",
+	[TEST_DEVICES] = "devices",
+	[TEST_FREEZER] = "freezer",
+};
+
+static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
+				char *buf)
+{
+	char *s = buf;
+	int level;
+
+	for (level = TEST_FIRST; level <= TEST_MAX; level++)
+		if (pm_tests[level]) {
+			if (level == pm_test_level)
+				s += sprintf(s, "[%s] ", pm_tests[level]);
+			else
+				s += sprintf(s, "%s ", pm_tests[level]);
+		}
+
+	if (s != buf)
+		/* convert the last space to a newline */
+		*(s-1) = '\n';
+
+	return (s - buf);
+}
+
+static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
+				const char *buf, size_t n)
+{
+	unsigned int sleep_flags;
+	const char * const *s;
+	int error = -EINVAL;
+	int level;
+	char *p;
+	int len;
+
+	p = memchr(buf, '\n', n);
+	len = p ? p - buf : n;
+
+	sleep_flags = lock_system_sleep();
+
+	level = TEST_FIRST;
+	for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
+		if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
+			pm_test_level = level;
+			error = 0;
+			break;
+		}
+
+	unlock_system_sleep(sleep_flags);
+
+	return error ? error : n;
+}
+
+power_attr(pm_test);
+#endif /* CONFIG_PM_SLEEP_DEBUG */
+
+static char *suspend_step_name(enum suspend_stat_step step)
+{
+	switch (step) {
+	case SUSPEND_FREEZE:
+		return "freeze";
+	case SUSPEND_PREPARE:
+		return "prepare";
+	case SUSPEND_SUSPEND:
+		return "suspend";
+	case SUSPEND_SUSPEND_NOIRQ:
+		return "suspend_noirq";
+	case SUSPEND_RESUME_NOIRQ:
+		return "resume_noirq";
+	case SUSPEND_RESUME:
+		return "resume";
+	default:
+		return "";
+	}
+}
+
+#define suspend_attr(_name)					\
+static ssize_t _name##_show(struct kobject *kobj,		\
+		struct kobj_attribute *attr, char *buf)		\
+{								\
+	return sprintf(buf, "%d\n", suspend_stats._name);	\
+}								\
+static struct kobj_attribute _name = __ATTR_RO(_name)
+
+suspend_attr(success);
+suspend_attr(fail);
+suspend_attr(failed_freeze);
+suspend_attr(failed_prepare);
+suspend_attr(failed_suspend);
+suspend_attr(failed_suspend_late);
+suspend_attr(failed_suspend_noirq);
+suspend_attr(failed_resume);
+suspend_attr(failed_resume_early);
+suspend_attr(failed_resume_noirq);
+
+static ssize_t last_failed_dev_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	int index;
+	char *last_failed_dev = NULL;
+
+	index = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
+	index %= REC_FAILED_NUM;
+	last_failed_dev = suspend_stats.failed_devs[index];
+
+	return sprintf(buf, "%s\n", last_failed_dev);
+}
+static struct kobj_attribute last_failed_dev = __ATTR_RO(last_failed_dev);
+
+static ssize_t last_failed_errno_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	int index;
+	int last_failed_errno;
+
+	index = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
+	index %= REC_FAILED_NUM;
+	last_failed_errno = suspend_stats.errno[index];
+
+	return sprintf(buf, "%d\n", last_failed_errno);
+}
+static struct kobj_attribute last_failed_errno = __ATTR_RO(last_failed_errno);
+
+static ssize_t last_failed_step_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	int index;
+	enum suspend_stat_step step;
+	char *last_failed_step = NULL;
+
+	index = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
+	index %= REC_FAILED_NUM;
+	step = suspend_stats.failed_steps[index];
+	last_failed_step = suspend_step_name(step);
+
+	return sprintf(buf, "%s\n", last_failed_step);
+}
+static struct kobj_attribute last_failed_step = __ATTR_RO(last_failed_step);
+
+static struct attribute *suspend_attrs[] = {
+	&success.attr,
+	&fail.attr,
+	&failed_freeze.attr,
+	&failed_prepare.attr,
+	&failed_suspend.attr,
+	&failed_suspend_late.attr,
+	&failed_suspend_noirq.attr,
+	&failed_resume.attr,
+	&failed_resume_early.attr,
+	&failed_resume_noirq.attr,
+	&last_failed_dev.attr,
+	&last_failed_errno.attr,
+	&last_failed_step.attr,
+	NULL,
+};
+
+static const struct attribute_group suspend_attr_group = {
+	.name = "suspend_stats",
+	.attrs = suspend_attrs,
+};
+
+#ifdef CONFIG_DEBUG_FS
+static int suspend_stats_show(struct seq_file *s, void *unused)
+{
+	int i, index, last_dev, last_errno, last_step;
+
+	last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
+	last_dev %= REC_FAILED_NUM;
+	last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
+	last_errno %= REC_FAILED_NUM;
+	last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
+	last_step %= REC_FAILED_NUM;
+	seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
+			"%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
+			"success", suspend_stats.success,
+			"fail", suspend_stats.fail,
+			"failed_freeze", suspend_stats.failed_freeze,
+			"failed_prepare", suspend_stats.failed_prepare,
+			"failed_suspend", suspend_stats.failed_suspend,
+			"failed_suspend_late",
+				suspend_stats.failed_suspend_late,
+			"failed_suspend_noirq",
+				suspend_stats.failed_suspend_noirq,
+			"failed_resume", suspend_stats.failed_resume,
+			"failed_resume_early",
+				suspend_stats.failed_resume_early,
+			"failed_resume_noirq",
+				suspend_stats.failed_resume_noirq);
+	seq_printf(s,	"failures:\n  last_failed_dev:\t%-s\n",
+			suspend_stats.failed_devs[last_dev]);
+	for (i = 1; i < REC_FAILED_NUM; i++) {
+		index = last_dev + REC_FAILED_NUM - i;
+		index %= REC_FAILED_NUM;
+		seq_printf(s, "\t\t\t%-s\n",
+			suspend_stats.failed_devs[index]);
+	}
+	seq_printf(s,	"  last_failed_errno:\t%-d\n",
+			suspend_stats.errno[last_errno]);
+	for (i = 1; i < REC_FAILED_NUM; i++) {
+		index = last_errno + REC_FAILED_NUM - i;
+		index %= REC_FAILED_NUM;
+		seq_printf(s, "\t\t\t%-d\n",
+			suspend_stats.errno[index]);
+	}
+	seq_printf(s,	"  last_failed_step:\t%-s\n",
+			suspend_step_name(
+				suspend_stats.failed_steps[last_step]));
+	for (i = 1; i < REC_FAILED_NUM; i++) {
+		index = last_step + REC_FAILED_NUM - i;
+		index %= REC_FAILED_NUM;
+		seq_printf(s, "\t\t\t%-s\n",
+			suspend_step_name(
+				suspend_stats.failed_steps[index]));
+	}
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(suspend_stats);
+
+static int __init pm_debugfs_init(void)
+{
+	debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
+			NULL, NULL, &suspend_stats_fops);
+	return 0;
+}
+
+late_initcall(pm_debugfs_init);
+#endif /* CONFIG_DEBUG_FS */
+
+#endif /* CONFIG_PM_SLEEP */
+
+#ifdef CONFIG_PM_SLEEP_DEBUG
+/*
+ * pm_print_times: print time taken by devices to suspend and resume.
+ *
+ * show() returns whether printing of suspend and resume times is enabled.
+ * store() accepts 0 or 1.  0 disables printing and 1 enables it.
+ */
+bool pm_print_times_enabled;
+
+static ssize_t pm_print_times_show(struct kobject *kobj,
+				   struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", pm_print_times_enabled);
+}
+
+static ssize_t pm_print_times_store(struct kobject *kobj,
+				    struct kobj_attribute *attr,
+				    const char *buf, size_t n)
+{
+	unsigned long val;
+
+	if (kstrtoul(buf, 10, &val))
+		return -EINVAL;
+
+	if (val > 1)
+		return -EINVAL;
+
+	pm_print_times_enabled = !!val;
+	return n;
+}
+
+power_attr(pm_print_times);
+
+static inline void pm_print_times_init(void)
+{
+	pm_print_times_enabled = !!initcall_debug;
+}
+
+static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
+					struct kobj_attribute *attr,
+					char *buf)
+{
+	if (!pm_wakeup_irq())
+		return -ENODATA;
+
+	return sprintf(buf, "%u\n", pm_wakeup_irq());
+}
+
+power_attr_ro(pm_wakeup_irq);
+
+bool pm_debug_messages_on __read_mostly;
+
+static ssize_t pm_debug_messages_show(struct kobject *kobj,
+				      struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", pm_debug_messages_on);
+}
+
+static ssize_t pm_debug_messages_store(struct kobject *kobj,
+				       struct kobj_attribute *attr,
+				       const char *buf, size_t n)
+{
+	unsigned long val;
+
+	if (kstrtoul(buf, 10, &val))
+		return -EINVAL;
+
+	if (val > 1)
+		return -EINVAL;
+
+	pm_debug_messages_on = !!val;
+	return n;
+}
+
+power_attr(pm_debug_messages);
+
+static int __init pm_debug_messages_setup(char *str)
+{
+	pm_debug_messages_on = true;
+	return 1;
+}
+__setup("pm_debug_messages", pm_debug_messages_setup);
+
+#else /* !CONFIG_PM_SLEEP_DEBUG */
+static inline void pm_print_times_init(void) {}
+#endif /* CONFIG_PM_SLEEP_DEBUG */
+
+struct kobject *power_kobj;
+
+/*
+ * state - control system sleep states.
+ *
+ * show() returns available sleep state labels, which may be "mem", "standby",
+ * "freeze" and "disk" (hibernation).
+ * See Documentation/admin-guide/pm/sleep-states.rst for a description of
+ * what they mean.
+ *
+ * store() accepts one of those strings, translates it into the proper
+ * enumerated value, and initiates a suspend transition.
+ */
+static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
+			  char *buf)
+{
+	char *s = buf;
+#ifdef CONFIG_SUSPEND
+	suspend_state_t i;
+
+	for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
+		if (pm_states[i])
+			s += sprintf(s,"%s ", pm_states[i]);
+
+#endif
+	if (hibernation_available())
+		s += sprintf(s, "disk ");
+	if (s != buf)
+		/* convert the last space to a newline */
+		*(s-1) = '\n';
+	return (s - buf);
+}
+
+static suspend_state_t decode_state(const char *buf, size_t n)
+{
+#ifdef CONFIG_SUSPEND
+	suspend_state_t state;
+#endif
+	char *p;
+	int len;
+
+	p = memchr(buf, '\n', n);
+	len = p ? p - buf : n;
+
+	/* Check hibernation first. */
+	if (len == 4 && str_has_prefix(buf, "disk"))
+		return PM_SUSPEND_MAX;
+
+#ifdef CONFIG_SUSPEND
+	for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
+		const char *label = pm_states[state];
+
+		if (label && len == strlen(label) && !strncmp(buf, label, len))
+			return state;
+	}
+#endif
+
+	return PM_SUSPEND_ON;
+}
+
+static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
+			   const char *buf, size_t n)
+{
+	suspend_state_t state;
+	int error;
+
+	error = pm_autosleep_lock();
+	if (error)
+		return error;
+
+	if (pm_autosleep_state() > PM_SUSPEND_ON) {
+		error = -EBUSY;
+		goto out;
+	}
+
+	state = decode_state(buf, n);
+	if (state < PM_SUSPEND_MAX) {
+		if (state == PM_SUSPEND_MEM)
+			state = mem_sleep_current;
+
+		error = pm_suspend(state);
+	} else if (state == PM_SUSPEND_MAX) {
+		error = hibernate();
+	} else {
+		error = -EINVAL;
+	}
+
+ out:
+	pm_autosleep_unlock();
+	return error ? error : n;
+}
+
+power_attr(state);
+
+#ifdef CONFIG_PM_SLEEP
+/*
+ * The 'wakeup_count' attribute, along with the functions defined in
+ * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
+ * handled in a non-racy way.
+ *
+ * If a wakeup event occurs when the system is in a sleep state, it simply is
+ * woken up.  In turn, if an event that would wake the system up from a sleep
+ * state occurs when it is undergoing a transition to that sleep state, the
+ * transition should be aborted.  Moreover, if such an event occurs when the
+ * system is in the working state, an attempt to start a transition to the
+ * given sleep state should fail during certain period after the detection of
+ * the event.  Using the 'state' attribute alone is not sufficient to satisfy
+ * these requirements, because a wakeup event may occur exactly when 'state'
+ * is being written to and may be delivered to user space right before it is
+ * frozen, so the event will remain only partially processed until the system is
+ * woken up by another event.  In particular, it won't cause the transition to
+ * a sleep state to be aborted.
+ *
+ * This difficulty may be overcome if user space uses 'wakeup_count' before
+ * writing to 'state'.  It first should read from 'wakeup_count' and store
+ * the read value.  Then, after carrying out its own preparations for the system
+ * transition to a sleep state, it should write the stored value to
+ * 'wakeup_count'.  If that fails, at least one wakeup event has occurred since
+ * 'wakeup_count' was read and 'state' should not be written to.  Otherwise, it
+ * is allowed to write to 'state', but the transition will be aborted if there
+ * are any wakeup events detected after 'wakeup_count' was written to.
+ */
+
+static ssize_t wakeup_count_show(struct kobject *kobj,
+				struct kobj_attribute *attr,
+				char *buf)
+{
+	unsigned int val;
+
+	return pm_get_wakeup_count(&val, true) ?
+		sprintf(buf, "%u\n", val) : -EINTR;
+}
+
+static ssize_t wakeup_count_store(struct kobject *kobj,
+				struct kobj_attribute *attr,
+				const char *buf, size_t n)
+{
+	unsigned int val;
+	int error;
+
+	error = pm_autosleep_lock();
+	if (error)
+		return error;
+
+	if (pm_autosleep_state() > PM_SUSPEND_ON) {
+		error = -EBUSY;
+		goto out;
+	}
+
+	error = -EINVAL;
+	if (sscanf(buf, "%u", &val) == 1) {
+		if (pm_save_wakeup_count(val))
+			error = n;
+		else
+			pm_print_active_wakeup_sources();
+	}
+
+ out:
+	pm_autosleep_unlock();
+	return error;
+}
+
+power_attr(wakeup_count);
+
+#ifdef CONFIG_PM_AUTOSLEEP
+static ssize_t autosleep_show(struct kobject *kobj,
+			      struct kobj_attribute *attr,
+			      char *buf)
+{
+	suspend_state_t state = pm_autosleep_state();
+
+	if (state == PM_SUSPEND_ON)
+		return sprintf(buf, "off\n");
+
+#ifdef CONFIG_SUSPEND
+	if (state < PM_SUSPEND_MAX)
+		return sprintf(buf, "%s\n", pm_states[state] ?
+					pm_states[state] : "error");
+#endif
+#ifdef CONFIG_HIBERNATION
+	return sprintf(buf, "disk\n");
+#else
+	return sprintf(buf, "error");
+#endif
+}
+
+static ssize_t autosleep_store(struct kobject *kobj,
+			       struct kobj_attribute *attr,
+			       const char *buf, size_t n)
+{
+	suspend_state_t state = decode_state(buf, n);
+	int error;
+
+	if (state == PM_SUSPEND_ON
+	    && strcmp(buf, "off") && strcmp(buf, "off\n"))
+		return -EINVAL;
+
+	if (state == PM_SUSPEND_MEM)
+		state = mem_sleep_current;
+
+	error = pm_autosleep_set_state(state);
+	return error ? error : n;
+}
+
+power_attr(autosleep);
+#endif /* CONFIG_PM_AUTOSLEEP */
+
+#ifdef CONFIG_PM_WAKELOCKS
+static ssize_t wake_lock_show(struct kobject *kobj,
+			      struct kobj_attribute *attr,
+			      char *buf)
+{
+	return pm_show_wakelocks(buf, true);
+}
+
+static ssize_t wake_lock_store(struct kobject *kobj,
+			       struct kobj_attribute *attr,
+			       const char *buf, size_t n)
+{
+	int error = pm_wake_lock(buf);
+	return error ? error : n;
+}
+
+power_attr(wake_lock);
+
+static ssize_t wake_unlock_show(struct kobject *kobj,
+				struct kobj_attribute *attr,
+				char *buf)
+{
+	return pm_show_wakelocks(buf, false);
+}
+
+static ssize_t wake_unlock_store(struct kobject *kobj,
+				 struct kobj_attribute *attr,
+				 const char *buf, size_t n)
+{
+	int error = pm_wake_unlock(buf);
+	return error ? error : n;
+}
+
+power_attr(wake_unlock);
+
+#endif /* CONFIG_PM_WAKELOCKS */
+#endif /* CONFIG_PM_SLEEP */
+
+#ifdef CONFIG_PM_TRACE
+int pm_trace_enabled;
+
+static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
+			     char *buf)
+{
+	return sprintf(buf, "%d\n", pm_trace_enabled);
+}
+
+static ssize_t
+pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
+	       const char *buf, size_t n)
+{
+	int val;
+
+	if (sscanf(buf, "%d", &val) == 1) {
+		pm_trace_enabled = !!val;
+		if (pm_trace_enabled) {
+			pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
+				"PM: Correct system time has to be restored manually after resume.\n");
+		}
+		return n;
+	}
+	return -EINVAL;
+}
+
+power_attr(pm_trace);
+
+static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
+				       struct kobj_attribute *attr,
+				       char *buf)
+{
+	return show_trace_dev_match(buf, PAGE_SIZE);
+}
+
+power_attr_ro(pm_trace_dev_match);
+
+#endif /* CONFIG_PM_TRACE */
+
+#ifdef CONFIG_FREEZER
+static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
+				      struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%u\n", freeze_timeout_msecs);
+}
+
+static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
+				       struct kobj_attribute *attr,
+				       const char *buf, size_t n)
+{
+	unsigned long val;
+
+	if (kstrtoul(buf, 10, &val))
+		return -EINVAL;
+
+	freeze_timeout_msecs = val;
+	return n;
+}
+
+power_attr(pm_freeze_timeout);
+
+#endif	/* CONFIG_FREEZER*/
+
+static struct attribute * g[] = {
+	&state_attr.attr,
+#ifdef CONFIG_PM_TRACE
+	&pm_trace_attr.attr,
+	&pm_trace_dev_match_attr.attr,
+#endif
+#ifdef CONFIG_PM_SLEEP
+	&pm_async_attr.attr,
+	&wakeup_count_attr.attr,
+#ifdef CONFIG_SUSPEND
+	&mem_sleep_attr.attr,
+	&sync_on_suspend_attr.attr,
+#endif
+#ifdef CONFIG_PM_AUTOSLEEP
+	&autosleep_attr.attr,
+#endif
+#ifdef CONFIG_PM_WAKELOCKS
+	&wake_lock_attr.attr,
+	&wake_unlock_attr.attr,
+#endif
+#ifdef CONFIG_PM_SLEEP_DEBUG
+	&pm_test_attr.attr,
+	&pm_print_times_attr.attr,
+	&pm_wakeup_irq_attr.attr,
+	&pm_debug_messages_attr.attr,
+#endif
+#endif
+#ifdef CONFIG_FREEZER
+	&pm_freeze_timeout_attr.attr,
+#endif
+	NULL,
+};
+
+static const struct attribute_group attr_group = {
+	.attrs = g,
+};
+
+static const struct attribute_group *attr_groups[] = {
+	&attr_group,
+#ifdef CONFIG_PM_SLEEP
+	&suspend_attr_group,
+#endif
+	NULL,
+};
+
+struct workqueue_struct *pm_wq;
+EXPORT_SYMBOL_GPL(pm_wq);
+
+static int __init pm_start_workqueue(void)
+{
+	pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
+
+	return pm_wq ? 0 : -ENOMEM;
+}
+
+static int __init pm_init(void)
+{
+	int error = pm_start_workqueue();
+	if (error)
+		return error;
+	hibernate_image_size_init();
+	hibernate_reserved_size_init();
+	pm_states_init();
+	power_kobj = kobject_create_and_add("power", NULL);
+	if (!power_kobj)
+		return -ENOMEM;
+	error = sysfs_create_groups(power_kobj, attr_groups);
+	if (error)
+		return error;
+	pm_print_times_init();
+	return pm_autosleep_init();
+}
+
+core_initcall(pm_init);
diff --git a/kernel/power/power.h b/kernel/power/power.h
new file mode 100644
index 000000000..b83c8d5e1
--- /dev/null
+++ b/kernel/power/power.h
@@ -0,0 +1,328 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/suspend.h>
+#include <linux/suspend_ioctls.h>
+#include <linux/utsname.h>
+#include <linux/freezer.h>
+#include <linux/compiler.h>
+#include <linux/cpu.h>
+#include <linux/cpuidle.h>
+
+struct swsusp_info {
+	struct new_utsname	uts;
+	u32			version_code;
+	unsigned long		num_physpages;
+	int			cpus;
+	unsigned long		image_pages;
+	unsigned long		pages;
+	unsigned long		size;
+} __aligned(PAGE_SIZE);
+
+#ifdef CONFIG_HIBERNATION
+/* kernel/power/snapshot.c */
+extern void __init hibernate_reserved_size_init(void);
+extern void __init hibernate_image_size_init(void);
+
+#ifdef CONFIG_ARCH_HIBERNATION_HEADER
+/* Maximum size of architecture specific data in a hibernation header */
+#define MAX_ARCH_HEADER_SIZE	(sizeof(struct new_utsname) + 4)
+
+extern int arch_hibernation_header_save(void *addr, unsigned int max_size);
+extern int arch_hibernation_header_restore(void *addr);
+
+static inline int init_header_complete(struct swsusp_info *info)
+{
+	return arch_hibernation_header_save(info, MAX_ARCH_HEADER_SIZE);
+}
+
+static inline const char *check_image_kernel(struct swsusp_info *info)
+{
+	return arch_hibernation_header_restore(info) ?
+			"architecture specific data" : NULL;
+}
+#endif /* CONFIG_ARCH_HIBERNATION_HEADER */
+
+extern int hibernate_resume_nonboot_cpu_disable(void);
+
+/*
+ * Keep some memory free so that I/O operations can succeed without paging
+ * [Might this be more than 4 MB?]
+ */
+#define PAGES_FOR_IO	((4096 * 1024) >> PAGE_SHIFT)
+
+/*
+ * Keep 1 MB of memory free so that device drivers can allocate some pages in
+ * their .suspend() routines without breaking the suspend to disk.
+ */
+#define SPARE_PAGES	((1024 * 1024) >> PAGE_SHIFT)
+
+asmlinkage int swsusp_save(void);
+
+/* kernel/power/hibernate.c */
+extern bool freezer_test_done;
+extern bool snapshot_test;
+
+extern int hibernation_snapshot(int platform_mode);
+extern int hibernation_restore(int platform_mode);
+extern int hibernation_platform_enter(void);
+
+#ifdef CONFIG_STRICT_KERNEL_RWX
+/* kernel/power/snapshot.c */
+extern void enable_restore_image_protection(void);
+#else
+static inline void enable_restore_image_protection(void) {}
+#endif /* CONFIG_STRICT_KERNEL_RWX */
+
+#else /* !CONFIG_HIBERNATION */
+
+static inline void hibernate_reserved_size_init(void) {}
+static inline void hibernate_image_size_init(void) {}
+#endif /* !CONFIG_HIBERNATION */
+
+#define power_attr(_name) \
+static struct kobj_attribute _name##_attr = {	\
+	.attr	= {				\
+		.name = __stringify(_name),	\
+		.mode = 0644,			\
+	},					\
+	.show	= _name##_show,			\
+	.store	= _name##_store,		\
+}
+
+#define power_attr_ro(_name) \
+static struct kobj_attribute _name##_attr = {	\
+	.attr	= {				\
+		.name = __stringify(_name),	\
+		.mode = S_IRUGO,		\
+	},					\
+	.show	= _name##_show,			\
+}
+
+/* Preferred image size in bytes (default 500 MB) */
+extern unsigned long image_size;
+/* Size of memory reserved for drivers (default SPARE_PAGES x PAGE_SIZE) */
+extern unsigned long reserved_size;
+extern int in_suspend;
+extern dev_t swsusp_resume_device;
+extern sector_t swsusp_resume_block;
+
+extern int create_basic_memory_bitmaps(void);
+extern void free_basic_memory_bitmaps(void);
+extern int hibernate_preallocate_memory(void);
+
+extern void clear_or_poison_free_pages(void);
+
+/**
+ *	Auxiliary structure used for reading the snapshot image data and
+ *	metadata from and writing them to the list of page backup entries
+ *	(PBEs) which is the main data structure of swsusp.
+ *
+ *	Using struct snapshot_handle we can transfer the image, including its
+ *	metadata, as a continuous sequence of bytes with the help of
+ *	snapshot_read_next() and snapshot_write_next().
+ *
+ *	The code that writes the image to a storage or transfers it to
+ *	the user land is required to use snapshot_read_next() for this
+ *	purpose and it should not make any assumptions regarding the internal
+ *	structure of the image.  Similarly, the code that reads the image from
+ *	a storage or transfers it from the user land is required to use
+ *	snapshot_write_next().
+ *
+ *	This may allow us to change the internal structure of the image
+ *	in the future with considerably less effort.
+ */
+
+struct snapshot_handle {
+	unsigned int	cur;	/* number of the block of PAGE_SIZE bytes the
+				 * next operation will refer to (ie. current)
+				 */
+	void		*buffer;	/* address of the block to read from
+					 * or write to
+					 */
+	int		sync_read;	/* Set to one to notify the caller of
+					 * snapshot_write_next() that it may
+					 * need to call wait_on_bio_chain()
+					 */
+};
+
+/* This macro returns the address from/to which the caller of
+ * snapshot_read_next()/snapshot_write_next() is allowed to
+ * read/write data after the function returns
+ */
+#define data_of(handle)	((handle).buffer)
+
+extern unsigned int snapshot_additional_pages(struct zone *zone);
+extern unsigned long snapshot_get_image_size(void);
+extern int snapshot_read_next(struct snapshot_handle *handle);
+extern int snapshot_write_next(struct snapshot_handle *handle);
+extern void snapshot_write_finalize(struct snapshot_handle *handle);
+extern int snapshot_image_loaded(struct snapshot_handle *handle);
+
+extern bool hibernate_acquire(void);
+extern void hibernate_release(void);
+
+extern sector_t alloc_swapdev_block(int swap);
+extern void free_all_swap_pages(int swap);
+extern int swsusp_swap_in_use(void);
+
+/*
+ * Flags that can be passed from the hibernatig hernel to the "boot" kernel in
+ * the image header.
+ */
+#define SF_PLATFORM_MODE	1
+#define SF_NOCOMPRESS_MODE	2
+#define SF_CRC32_MODE	        4
+#define SF_HW_SIG		8
+
+/* kernel/power/hibernate.c */
+extern int swsusp_check(void);
+extern void swsusp_free(void);
+extern int swsusp_read(unsigned int *flags_p);
+extern int swsusp_write(unsigned int flags);
+extern void swsusp_close(fmode_t);
+#ifdef CONFIG_SUSPEND
+extern int swsusp_unmark(void);
+#endif
+
+struct __kernel_old_timeval;
+/* kernel/power/swsusp.c */
+extern void swsusp_show_speed(ktime_t, ktime_t, unsigned int, char *);
+
+#ifdef CONFIG_SUSPEND
+/* kernel/power/suspend.c */
+extern const char * const pm_labels[];
+extern const char *pm_states[];
+extern const char *mem_sleep_states[];
+
+extern int suspend_devices_and_enter(suspend_state_t state);
+#else /* !CONFIG_SUSPEND */
+#define mem_sleep_current	PM_SUSPEND_ON
+
+static inline int suspend_devices_and_enter(suspend_state_t state)
+{
+	return -ENOSYS;
+}
+#endif /* !CONFIG_SUSPEND */
+
+#ifdef CONFIG_PM_TEST_SUSPEND
+/* kernel/power/suspend_test.c */
+extern void suspend_test_start(void);
+extern void suspend_test_finish(const char *label);
+#else /* !CONFIG_PM_TEST_SUSPEND */
+static inline void suspend_test_start(void) {}
+static inline void suspend_test_finish(const char *label) {}
+#endif /* !CONFIG_PM_TEST_SUSPEND */
+
+#ifdef CONFIG_PM_SLEEP
+/* kernel/power/main.c */
+extern int pm_notifier_call_chain_robust(unsigned long val_up, unsigned long val_down);
+extern int pm_notifier_call_chain(unsigned long val);
+#endif
+
+#ifdef CONFIG_HIGHMEM
+int restore_highmem(void);
+#else
+static inline unsigned int count_highmem_pages(void) { return 0; }
+static inline int restore_highmem(void) { return 0; }
+#endif
+
+/*
+ * Suspend test levels
+ */
+enum {
+	/* keep first */
+	TEST_NONE,
+	TEST_CORE,
+	TEST_CPUS,
+	TEST_PLATFORM,
+	TEST_DEVICES,
+	TEST_FREEZER,
+	/* keep last */
+	__TEST_AFTER_LAST
+};
+
+#define TEST_FIRST	TEST_NONE
+#define TEST_MAX	(__TEST_AFTER_LAST - 1)
+
+#ifdef CONFIG_PM_SLEEP_DEBUG
+extern int pm_test_level;
+#else
+#define pm_test_level	(TEST_NONE)
+#endif
+
+#ifdef CONFIG_SUSPEND_FREEZER
+static inline int suspend_freeze_processes(void)
+{
+	int error;
+
+	error = freeze_processes();
+	/*
+	 * freeze_processes() automatically thaws every task if freezing
+	 * fails. So we need not do anything extra upon error.
+	 */
+	if (error)
+		return error;
+
+	error = freeze_kernel_threads();
+	/*
+	 * freeze_kernel_threads() thaws only kernel threads upon freezing
+	 * failure. So we have to thaw the userspace tasks ourselves.
+	 */
+	if (error)
+		thaw_processes();
+
+	return error;
+}
+
+static inline void suspend_thaw_processes(void)
+{
+	thaw_processes();
+}
+#else
+static inline int suspend_freeze_processes(void)
+{
+	return 0;
+}
+
+static inline void suspend_thaw_processes(void)
+{
+}
+#endif
+
+#ifdef CONFIG_PM_AUTOSLEEP
+
+/* kernel/power/autosleep.c */
+extern int pm_autosleep_init(void);
+extern int pm_autosleep_lock(void);
+extern void pm_autosleep_unlock(void);
+extern suspend_state_t pm_autosleep_state(void);
+extern int pm_autosleep_set_state(suspend_state_t state);
+
+#else /* !CONFIG_PM_AUTOSLEEP */
+
+static inline int pm_autosleep_init(void) { return 0; }
+static inline int pm_autosleep_lock(void) { return 0; }
+static inline void pm_autosleep_unlock(void) {}
+static inline suspend_state_t pm_autosleep_state(void) { return PM_SUSPEND_ON; }
+
+#endif /* !CONFIG_PM_AUTOSLEEP */
+
+#ifdef CONFIG_PM_WAKELOCKS
+
+/* kernel/power/wakelock.c */
+extern ssize_t pm_show_wakelocks(char *buf, bool show_active);
+extern int pm_wake_lock(const char *buf);
+extern int pm_wake_unlock(const char *buf);
+
+#endif /* !CONFIG_PM_WAKELOCKS */
+
+static inline int pm_sleep_disable_secondary_cpus(void)
+{
+	cpuidle_pause();
+	return suspend_disable_secondary_cpus();
+}
+
+static inline void pm_sleep_enable_secondary_cpus(void)
+{
+	suspend_enable_secondary_cpus();
+	cpuidle_resume();
+}
diff --git a/kernel/power/poweroff.c b/kernel/power/poweroff.c
new file mode 100644
index 000000000..562aa0e45
--- /dev/null
+++ b/kernel/power/poweroff.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * poweroff.c - sysrq handler to gracefully power down machine.
+ */
+
+#include <linux/kernel.h>
+#include <linux/sysrq.h>
+#include <linux/init.h>
+#include <linux/pm.h>
+#include <linux/workqueue.h>
+#include <linux/reboot.h>
+#include <linux/cpumask.h>
+
+/*
+ * When the user hits Sys-Rq o to power down the machine this is the
+ * callback we use.
+ */
+
+static void do_poweroff(struct work_struct *dummy)
+{
+	kernel_power_off();
+}
+
+static DECLARE_WORK(poweroff_work, do_poweroff);
+
+static void handle_poweroff(int key)
+{
+	/* run sysrq poweroff on boot cpu */
+	schedule_work_on(cpumask_first(cpu_online_mask), &poweroff_work);
+}
+
+static const struct sysrq_key_op	sysrq_poweroff_op = {
+	.handler        = handle_poweroff,
+	.help_msg       = "poweroff(o)",
+	.action_msg     = "Power Off",
+	.enable_mask	= SYSRQ_ENABLE_BOOT,
+};
+
+static int __init pm_sysrq_init(void)
+{
+	register_sysrq_key('o', &sysrq_poweroff_op);
+	return 0;
+}
+
+subsys_initcall(pm_sysrq_init);
diff --git a/kernel/power/process.c b/kernel/power/process.c
new file mode 100644
index 000000000..beeab7f9f
--- /dev/null
+++ b/kernel/power/process.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * drivers/power/process.c - Functions for starting/stopping processes on
+ *                           suspend transitions.
+ *
+ * Originally from swsusp.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/oom.h>
+#include <linux/suspend.h>
+#include <linux/module.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/task.h>
+#include <linux/syscalls.h>
+#include <linux/freezer.h>
+#include <linux/delay.h>
+#include <linux/workqueue.h>
+#include <linux/kmod.h>
+#include <trace/events/power.h>
+#include <linux/cpuset.h>
+
+/*
+ * Timeout for stopping processes
+ */
+unsigned int __read_mostly freeze_timeout_msecs = 20 * MSEC_PER_SEC;
+
+static int try_to_freeze_tasks(bool user_only)
+{
+	const char *what = user_only ? "user space processes" :
+					"remaining freezable tasks";
+	struct task_struct *g, *p;
+	unsigned long end_time;
+	unsigned int todo;
+	bool wq_busy = false;
+	ktime_t start, end, elapsed;
+	unsigned int elapsed_msecs;
+	bool wakeup = false;
+	int sleep_usecs = USEC_PER_MSEC;
+
+	pr_info("Freezing %s\n", what);
+
+	start = ktime_get_boottime();
+
+	end_time = jiffies + msecs_to_jiffies(freeze_timeout_msecs);
+
+	if (!user_only)
+		freeze_workqueues_begin();
+
+	while (true) {
+		todo = 0;
+		read_lock(&tasklist_lock);
+		for_each_process_thread(g, p) {
+			if (p == current || !freeze_task(p))
+				continue;
+
+			todo++;
+		}
+		read_unlock(&tasklist_lock);
+
+		if (!user_only) {
+			wq_busy = freeze_workqueues_busy();
+			todo += wq_busy;
+		}
+
+		if (!todo || time_after(jiffies, end_time))
+			break;
+
+		if (pm_wakeup_pending()) {
+			wakeup = true;
+			break;
+		}
+
+		/*
+		 * We need to retry, but first give the freezing tasks some
+		 * time to enter the refrigerator.  Start with an initial
+		 * 1 ms sleep followed by exponential backoff until 8 ms.
+		 */
+		usleep_range(sleep_usecs / 2, sleep_usecs);
+		if (sleep_usecs < 8 * USEC_PER_MSEC)
+			sleep_usecs *= 2;
+	}
+
+	end = ktime_get_boottime();
+	elapsed = ktime_sub(end, start);
+	elapsed_msecs = ktime_to_ms(elapsed);
+
+	if (todo) {
+		pr_err("Freezing of tasks %s after %d.%03d seconds "
+		       "(%d tasks refusing to freeze, wq_busy=%d):\n",
+		       wakeup ? "aborted" : "failed",
+		       elapsed_msecs / 1000, elapsed_msecs % 1000,
+		       todo - wq_busy, wq_busy);
+
+		if (wq_busy)
+			show_all_workqueues();
+
+		if (!wakeup || pm_debug_messages_on) {
+			read_lock(&tasklist_lock);
+			for_each_process_thread(g, p) {
+				if (p != current && freezing(p) && !frozen(p))
+					sched_show_task(p);
+			}
+			read_unlock(&tasklist_lock);
+		}
+	} else {
+		pr_info("Freezing %s completed (elapsed %d.%03d seconds)\n",
+			what, elapsed_msecs / 1000, elapsed_msecs % 1000);
+	}
+
+	return todo ? -EBUSY : 0;
+}
+
+/**
+ * freeze_processes - Signal user space processes to enter the refrigerator.
+ * The current thread will not be frozen.  The same process that calls
+ * freeze_processes must later call thaw_processes.
+ *
+ * On success, returns 0.  On failure, -errno and system is fully thawed.
+ */
+int freeze_processes(void)
+{
+	int error;
+
+	error = __usermodehelper_disable(UMH_FREEZING);
+	if (error)
+		return error;
+
+	/* Make sure this task doesn't get frozen */
+	current->flags |= PF_SUSPEND_TASK;
+
+	if (!pm_freezing)
+		static_branch_inc(&freezer_active);
+
+	pm_wakeup_clear(0);
+	pm_freezing = true;
+	error = try_to_freeze_tasks(true);
+	if (!error)
+		__usermodehelper_set_disable_depth(UMH_DISABLED);
+
+	BUG_ON(in_atomic());
+
+	/*
+	 * Now that the whole userspace is frozen we need to disable
+	 * the OOM killer to disallow any further interference with
+	 * killable tasks. There is no guarantee oom victims will
+	 * ever reach a point they go away we have to wait with a timeout.
+	 */
+	if (!error && !oom_killer_disable(msecs_to_jiffies(freeze_timeout_msecs)))
+		error = -EBUSY;
+
+	if (error)
+		thaw_processes();
+	return error;
+}
+
+/**
+ * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator.
+ *
+ * On success, returns 0.  On failure, -errno and only the kernel threads are
+ * thawed, so as to give a chance to the caller to do additional cleanups
+ * (if any) before thawing the userspace tasks. So, it is the responsibility
+ * of the caller to thaw the userspace tasks, when the time is right.
+ */
+int freeze_kernel_threads(void)
+{
+	int error;
+
+	pm_nosig_freezing = true;
+	error = try_to_freeze_tasks(false);
+
+	BUG_ON(in_atomic());
+
+	if (error)
+		thaw_kernel_threads();
+	return error;
+}
+
+void thaw_processes(void)
+{
+	struct task_struct *g, *p;
+	struct task_struct *curr = current;
+
+	trace_suspend_resume(TPS("thaw_processes"), 0, true);
+	if (pm_freezing)
+		static_branch_dec(&freezer_active);
+	pm_freezing = false;
+	pm_nosig_freezing = false;
+
+	oom_killer_enable();
+
+	pr_info("Restarting tasks ... ");
+
+	__usermodehelper_set_disable_depth(UMH_FREEZING);
+	thaw_workqueues();
+
+	cpuset_wait_for_hotplug();
+
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, p) {
+		/* No other threads should have PF_SUSPEND_TASK set */
+		WARN_ON((p != curr) && (p->flags & PF_SUSPEND_TASK));
+		__thaw_task(p);
+	}
+	read_unlock(&tasklist_lock);
+
+	WARN_ON(!(curr->flags & PF_SUSPEND_TASK));
+	curr->flags &= ~PF_SUSPEND_TASK;
+
+	usermodehelper_enable();
+
+	schedule();
+	pr_cont("done.\n");
+	trace_suspend_resume(TPS("thaw_processes"), 0, false);
+}
+
+void thaw_kernel_threads(void)
+{
+	struct task_struct *g, *p;
+
+	pm_nosig_freezing = false;
+	pr_info("Restarting kernel threads ... ");
+
+	thaw_workqueues();
+
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, p) {
+		if (p->flags & PF_KTHREAD)
+			__thaw_task(p);
+	}
+	read_unlock(&tasklist_lock);
+
+	schedule();
+	pr_cont("done.\n");
+}
diff --git a/kernel/power/qos.c b/kernel/power/qos.c
new file mode 100644
index 000000000..782d3b41c
--- /dev/null
+++ b/kernel/power/qos.c
@@ -0,0 +1,678 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Power Management Quality of Service (PM QoS) support base.
+ *
+ * Copyright (C) 2020 Intel Corporation
+ *
+ * Authors:
+ *	Mark Gross <mgross@linux.intel.com>
+ *	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ *
+ * Provided here is an interface for specifying PM QoS dependencies.  It allows
+ * entities depending on QoS constraints to register their requests which are
+ * aggregated as appropriate to produce effective constraints (target values)
+ * that can be monitored by entities needing to respect them, either by polling
+ * or through a built-in notification mechanism.
+ *
+ * In addition to the basic functionality, more specific interfaces for managing
+ * global CPU latency QoS requests and frequency QoS requests are provided.
+ */
+
+/*#define DEBUG*/
+
+#include <linux/pm_qos.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/string.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+#include <linux/uaccess.h>
+#include <linux/export.h>
+#include <trace/events/power.h>
+
+/*
+ * locking rule: all changes to constraints or notifiers lists
+ * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
+ * held, taken with _irqsave.  One lock to rule them all
+ */
+static DEFINE_SPINLOCK(pm_qos_lock);
+
+/**
+ * pm_qos_read_value - Return the current effective constraint value.
+ * @c: List of PM QoS constraint requests.
+ */
+s32 pm_qos_read_value(struct pm_qos_constraints *c)
+{
+	return READ_ONCE(c->target_value);
+}
+
+static int pm_qos_get_value(struct pm_qos_constraints *c)
+{
+	if (plist_head_empty(&c->list))
+		return c->no_constraint_value;
+
+	switch (c->type) {
+	case PM_QOS_MIN:
+		return plist_first(&c->list)->prio;
+
+	case PM_QOS_MAX:
+		return plist_last(&c->list)->prio;
+
+	default:
+		WARN(1, "Unknown PM QoS type in %s\n", __func__);
+		return PM_QOS_DEFAULT_VALUE;
+	}
+}
+
+static void pm_qos_set_value(struct pm_qos_constraints *c, s32 value)
+{
+	WRITE_ONCE(c->target_value, value);
+}
+
+/**
+ * pm_qos_update_target - Update a list of PM QoS constraint requests.
+ * @c: List of PM QoS requests.
+ * @node: Target list entry.
+ * @action: Action to carry out (add, update or remove).
+ * @value: New request value for the target list entry.
+ *
+ * Update the given list of PM QoS constraint requests, @c, by carrying an
+ * @action involving the @node list entry and @value on it.
+ *
+ * The recognized values of @action are PM_QOS_ADD_REQ (store @value in @node
+ * and add it to the list), PM_QOS_UPDATE_REQ (remove @node from the list, store
+ * @value in it and add it to the list again), and PM_QOS_REMOVE_REQ (remove
+ * @node from the list, ignore @value).
+ *
+ * Return: 1 if the aggregate constraint value has changed, 0  otherwise.
+ */
+int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
+			 enum pm_qos_req_action action, int value)
+{
+	int prev_value, curr_value, new_value;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+
+	prev_value = pm_qos_get_value(c);
+	if (value == PM_QOS_DEFAULT_VALUE)
+		new_value = c->default_value;
+	else
+		new_value = value;
+
+	switch (action) {
+	case PM_QOS_REMOVE_REQ:
+		plist_del(node, &c->list);
+		break;
+	case PM_QOS_UPDATE_REQ:
+		/*
+		 * To change the list, atomically remove, reinit with new value
+		 * and add, then see if the aggregate has changed.
+		 */
+		plist_del(node, &c->list);
+		fallthrough;
+	case PM_QOS_ADD_REQ:
+		plist_node_init(node, new_value);
+		plist_add(node, &c->list);
+		break;
+	default:
+		/* no action */
+		;
+	}
+
+	curr_value = pm_qos_get_value(c);
+	pm_qos_set_value(c, curr_value);
+
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+	trace_pm_qos_update_target(action, prev_value, curr_value);
+
+	if (prev_value == curr_value)
+		return 0;
+
+	if (c->notifiers)
+		blocking_notifier_call_chain(c->notifiers, curr_value, NULL);
+
+	return 1;
+}
+
+/**
+ * pm_qos_flags_remove_req - Remove device PM QoS flags request.
+ * @pqf: Device PM QoS flags set to remove the request from.
+ * @req: Request to remove from the set.
+ */
+static void pm_qos_flags_remove_req(struct pm_qos_flags *pqf,
+				    struct pm_qos_flags_request *req)
+{
+	s32 val = 0;
+
+	list_del(&req->node);
+	list_for_each_entry(req, &pqf->list, node)
+		val |= req->flags;
+
+	pqf->effective_flags = val;
+}
+
+/**
+ * pm_qos_update_flags - Update a set of PM QoS flags.
+ * @pqf: Set of PM QoS flags to update.
+ * @req: Request to add to the set, to modify, or to remove from the set.
+ * @action: Action to take on the set.
+ * @val: Value of the request to add or modify.
+ *
+ * Return: 1 if the aggregate constraint value has changed, 0 otherwise.
+ */
+bool pm_qos_update_flags(struct pm_qos_flags *pqf,
+			 struct pm_qos_flags_request *req,
+			 enum pm_qos_req_action action, s32 val)
+{
+	unsigned long irqflags;
+	s32 prev_value, curr_value;
+
+	spin_lock_irqsave(&pm_qos_lock, irqflags);
+
+	prev_value = list_empty(&pqf->list) ? 0 : pqf->effective_flags;
+
+	switch (action) {
+	case PM_QOS_REMOVE_REQ:
+		pm_qos_flags_remove_req(pqf, req);
+		break;
+	case PM_QOS_UPDATE_REQ:
+		pm_qos_flags_remove_req(pqf, req);
+		fallthrough;
+	case PM_QOS_ADD_REQ:
+		req->flags = val;
+		INIT_LIST_HEAD(&req->node);
+		list_add_tail(&req->node, &pqf->list);
+		pqf->effective_flags |= val;
+		break;
+	default:
+		/* no action */
+		;
+	}
+
+	curr_value = list_empty(&pqf->list) ? 0 : pqf->effective_flags;
+
+	spin_unlock_irqrestore(&pm_qos_lock, irqflags);
+
+	trace_pm_qos_update_flags(action, prev_value, curr_value);
+
+	return prev_value != curr_value;
+}
+
+#ifdef CONFIG_CPU_IDLE
+/* Definitions related to the CPU latency QoS. */
+
+static struct pm_qos_constraints cpu_latency_constraints = {
+	.list = PLIST_HEAD_INIT(cpu_latency_constraints.list),
+	.target_value = PM_QOS_CPU_LATENCY_DEFAULT_VALUE,
+	.default_value = PM_QOS_CPU_LATENCY_DEFAULT_VALUE,
+	.no_constraint_value = PM_QOS_CPU_LATENCY_DEFAULT_VALUE,
+	.type = PM_QOS_MIN,
+};
+
+/**
+ * cpu_latency_qos_limit - Return current system-wide CPU latency QoS limit.
+ */
+s32 cpu_latency_qos_limit(void)
+{
+	return pm_qos_read_value(&cpu_latency_constraints);
+}
+
+/**
+ * cpu_latency_qos_request_active - Check the given PM QoS request.
+ * @req: PM QoS request to check.
+ *
+ * Return: 'true' if @req has been added to the CPU latency QoS list, 'false'
+ * otherwise.
+ */
+bool cpu_latency_qos_request_active(struct pm_qos_request *req)
+{
+	return req->qos == &cpu_latency_constraints;
+}
+EXPORT_SYMBOL_GPL(cpu_latency_qos_request_active);
+
+static void cpu_latency_qos_apply(struct pm_qos_request *req,
+				  enum pm_qos_req_action action, s32 value)
+{
+	int ret = pm_qos_update_target(req->qos, &req->node, action, value);
+	if (ret > 0)
+		wake_up_all_idle_cpus();
+}
+
+/**
+ * cpu_latency_qos_add_request - Add new CPU latency QoS request.
+ * @req: Pointer to a preallocated handle.
+ * @value: Requested constraint value.
+ *
+ * Use @value to initialize the request handle pointed to by @req, insert it as
+ * a new entry to the CPU latency QoS list and recompute the effective QoS
+ * constraint for that list.
+ *
+ * Callers need to save the handle for later use in updates and removal of the
+ * QoS request represented by it.
+ */
+void cpu_latency_qos_add_request(struct pm_qos_request *req, s32 value)
+{
+	if (!req)
+		return;
+
+	if (cpu_latency_qos_request_active(req)) {
+		WARN(1, KERN_ERR "%s called for already added request\n", __func__);
+		return;
+	}
+
+	trace_pm_qos_add_request(value);
+
+	req->qos = &cpu_latency_constraints;
+	cpu_latency_qos_apply(req, PM_QOS_ADD_REQ, value);
+}
+EXPORT_SYMBOL_GPL(cpu_latency_qos_add_request);
+
+/**
+ * cpu_latency_qos_update_request - Modify existing CPU latency QoS request.
+ * @req : QoS request to update.
+ * @new_value: New requested constraint value.
+ *
+ * Use @new_value to update the QoS request represented by @req in the CPU
+ * latency QoS list along with updating the effective constraint value for that
+ * list.
+ */
+void cpu_latency_qos_update_request(struct pm_qos_request *req, s32 new_value)
+{
+	if (!req)
+		return;
+
+	if (!cpu_latency_qos_request_active(req)) {
+		WARN(1, KERN_ERR "%s called for unknown object\n", __func__);
+		return;
+	}
+
+	trace_pm_qos_update_request(new_value);
+
+	if (new_value == req->node.prio)
+		return;
+
+	cpu_latency_qos_apply(req, PM_QOS_UPDATE_REQ, new_value);
+}
+EXPORT_SYMBOL_GPL(cpu_latency_qos_update_request);
+
+/**
+ * cpu_latency_qos_remove_request - Remove existing CPU latency QoS request.
+ * @req: QoS request to remove.
+ *
+ * Remove the CPU latency QoS request represented by @req from the CPU latency
+ * QoS list along with updating the effective constraint value for that list.
+ */
+void cpu_latency_qos_remove_request(struct pm_qos_request *req)
+{
+	if (!req)
+		return;
+
+	if (!cpu_latency_qos_request_active(req)) {
+		WARN(1, KERN_ERR "%s called for unknown object\n", __func__);
+		return;
+	}
+
+	trace_pm_qos_remove_request(PM_QOS_DEFAULT_VALUE);
+
+	cpu_latency_qos_apply(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
+	memset(req, 0, sizeof(*req));
+}
+EXPORT_SYMBOL_GPL(cpu_latency_qos_remove_request);
+
+/* User space interface to the CPU latency QoS via misc device. */
+
+static int cpu_latency_qos_open(struct inode *inode, struct file *filp)
+{
+	struct pm_qos_request *req;
+
+	req = kzalloc(sizeof(*req), GFP_KERNEL);
+	if (!req)
+		return -ENOMEM;
+
+	cpu_latency_qos_add_request(req, PM_QOS_DEFAULT_VALUE);
+	filp->private_data = req;
+
+	return 0;
+}
+
+static int cpu_latency_qos_release(struct inode *inode, struct file *filp)
+{
+	struct pm_qos_request *req = filp->private_data;
+
+	filp->private_data = NULL;
+
+	cpu_latency_qos_remove_request(req);
+	kfree(req);
+
+	return 0;
+}
+
+static ssize_t cpu_latency_qos_read(struct file *filp, char __user *buf,
+				    size_t count, loff_t *f_pos)
+{
+	struct pm_qos_request *req = filp->private_data;
+	unsigned long flags;
+	s32 value;
+
+	if (!req || !cpu_latency_qos_request_active(req))
+		return -EINVAL;
+
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	value = pm_qos_get_value(&cpu_latency_constraints);
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+	return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32));
+}
+
+static ssize_t cpu_latency_qos_write(struct file *filp, const char __user *buf,
+				     size_t count, loff_t *f_pos)
+{
+	s32 value;
+
+	if (count == sizeof(s32)) {
+		if (copy_from_user(&value, buf, sizeof(s32)))
+			return -EFAULT;
+	} else {
+		int ret;
+
+		ret = kstrtos32_from_user(buf, count, 16, &value);
+		if (ret)
+			return ret;
+	}
+
+	cpu_latency_qos_update_request(filp->private_data, value);
+
+	return count;
+}
+
+static const struct file_operations cpu_latency_qos_fops = {
+	.write = cpu_latency_qos_write,
+	.read = cpu_latency_qos_read,
+	.open = cpu_latency_qos_open,
+	.release = cpu_latency_qos_release,
+	.llseek = noop_llseek,
+};
+
+static struct miscdevice cpu_latency_qos_miscdev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "cpu_dma_latency",
+	.fops = &cpu_latency_qos_fops,
+};
+
+static int __init cpu_latency_qos_init(void)
+{
+	int ret;
+
+	ret = misc_register(&cpu_latency_qos_miscdev);
+	if (ret < 0)
+		pr_err("%s: %s setup failed\n", __func__,
+		       cpu_latency_qos_miscdev.name);
+
+	return ret;
+}
+late_initcall(cpu_latency_qos_init);
+#endif /* CONFIG_CPU_IDLE */
+
+/* Definitions related to the frequency QoS below. */
+
+static inline bool freq_qos_value_invalid(s32 value)
+{
+	return value < 0 && value != PM_QOS_DEFAULT_VALUE;
+}
+
+/**
+ * freq_constraints_init - Initialize frequency QoS constraints.
+ * @qos: Frequency QoS constraints to initialize.
+ */
+void freq_constraints_init(struct freq_constraints *qos)
+{
+	struct pm_qos_constraints *c;
+
+	c = &qos->min_freq;
+	plist_head_init(&c->list);
+	c->target_value = FREQ_QOS_MIN_DEFAULT_VALUE;
+	c->default_value = FREQ_QOS_MIN_DEFAULT_VALUE;
+	c->no_constraint_value = FREQ_QOS_MIN_DEFAULT_VALUE;
+	c->type = PM_QOS_MAX;
+	c->notifiers = &qos->min_freq_notifiers;
+	BLOCKING_INIT_NOTIFIER_HEAD(c->notifiers);
+
+	c = &qos->max_freq;
+	plist_head_init(&c->list);
+	c->target_value = FREQ_QOS_MAX_DEFAULT_VALUE;
+	c->default_value = FREQ_QOS_MAX_DEFAULT_VALUE;
+	c->no_constraint_value = FREQ_QOS_MAX_DEFAULT_VALUE;
+	c->type = PM_QOS_MIN;
+	c->notifiers = &qos->max_freq_notifiers;
+	BLOCKING_INIT_NOTIFIER_HEAD(c->notifiers);
+}
+
+/**
+ * freq_qos_read_value - Get frequency QoS constraint for a given list.
+ * @qos: Constraints to evaluate.
+ * @type: QoS request type.
+ */
+s32 freq_qos_read_value(struct freq_constraints *qos,
+			enum freq_qos_req_type type)
+{
+	s32 ret;
+
+	switch (type) {
+	case FREQ_QOS_MIN:
+		ret = IS_ERR_OR_NULL(qos) ?
+			FREQ_QOS_MIN_DEFAULT_VALUE :
+			pm_qos_read_value(&qos->min_freq);
+		break;
+	case FREQ_QOS_MAX:
+		ret = IS_ERR_OR_NULL(qos) ?
+			FREQ_QOS_MAX_DEFAULT_VALUE :
+			pm_qos_read_value(&qos->max_freq);
+		break;
+	default:
+		WARN_ON(1);
+		ret = 0;
+	}
+
+	return ret;
+}
+
+/**
+ * freq_qos_apply - Add/modify/remove frequency QoS request.
+ * @req: Constraint request to apply.
+ * @action: Action to perform (add/update/remove).
+ * @value: Value to assign to the QoS request.
+ *
+ * This is only meant to be called from inside pm_qos, not drivers.
+ */
+int freq_qos_apply(struct freq_qos_request *req,
+			  enum pm_qos_req_action action, s32 value)
+{
+	int ret;
+
+	switch(req->type) {
+	case FREQ_QOS_MIN:
+		ret = pm_qos_update_target(&req->qos->min_freq, &req->pnode,
+					   action, value);
+		break;
+	case FREQ_QOS_MAX:
+		ret = pm_qos_update_target(&req->qos->max_freq, &req->pnode,
+					   action, value);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+/**
+ * freq_qos_add_request - Insert new frequency QoS request into a given list.
+ * @qos: Constraints to update.
+ * @req: Preallocated request object.
+ * @type: Request type.
+ * @value: Request value.
+ *
+ * Insert a new entry into the @qos list of requests, recompute the effective
+ * QoS constraint value for that list and initialize the @req object.  The
+ * caller needs to save that object for later use in updates and removal.
+ *
+ * Return 1 if the effective constraint value has changed, 0 if the effective
+ * constraint value has not changed, or a negative error code on failures.
+ */
+int freq_qos_add_request(struct freq_constraints *qos,
+			 struct freq_qos_request *req,
+			 enum freq_qos_req_type type, s32 value)
+{
+	int ret;
+
+	if (IS_ERR_OR_NULL(qos) || !req || freq_qos_value_invalid(value))
+		return -EINVAL;
+
+	if (WARN(freq_qos_request_active(req),
+		 "%s() called for active request\n", __func__))
+		return -EINVAL;
+
+	req->qos = qos;
+	req->type = type;
+	ret = freq_qos_apply(req, PM_QOS_ADD_REQ, value);
+	if (ret < 0) {
+		req->qos = NULL;
+		req->type = 0;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(freq_qos_add_request);
+
+/**
+ * freq_qos_update_request - Modify existing frequency QoS request.
+ * @req: Request to modify.
+ * @new_value: New request value.
+ *
+ * Update an existing frequency QoS request along with the effective constraint
+ * value for the list of requests it belongs to.
+ *
+ * Return 1 if the effective constraint value has changed, 0 if the effective
+ * constraint value has not changed, or a negative error code on failures.
+ */
+int freq_qos_update_request(struct freq_qos_request *req, s32 new_value)
+{
+	if (!req || freq_qos_value_invalid(new_value))
+		return -EINVAL;
+
+	if (WARN(!freq_qos_request_active(req),
+		 "%s() called for unknown object\n", __func__))
+		return -EINVAL;
+
+	if (req->pnode.prio == new_value)
+		return 0;
+
+	return freq_qos_apply(req, PM_QOS_UPDATE_REQ, new_value);
+}
+EXPORT_SYMBOL_GPL(freq_qos_update_request);
+
+/**
+ * freq_qos_remove_request - Remove frequency QoS request from its list.
+ * @req: Request to remove.
+ *
+ * Remove the given frequency QoS request from the list of constraints it
+ * belongs to and recompute the effective constraint value for that list.
+ *
+ * Return 1 if the effective constraint value has changed, 0 if the effective
+ * constraint value has not changed, or a negative error code on failures.
+ */
+int freq_qos_remove_request(struct freq_qos_request *req)
+{
+	int ret;
+
+	if (!req)
+		return -EINVAL;
+
+	if (WARN(!freq_qos_request_active(req),
+		 "%s() called for unknown object\n", __func__))
+		return -EINVAL;
+
+	ret = freq_qos_apply(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
+	req->qos = NULL;
+	req->type = 0;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(freq_qos_remove_request);
+
+/**
+ * freq_qos_add_notifier - Add frequency QoS change notifier.
+ * @qos: List of requests to add the notifier to.
+ * @type: Request type.
+ * @notifier: Notifier block to add.
+ */
+int freq_qos_add_notifier(struct freq_constraints *qos,
+			  enum freq_qos_req_type type,
+			  struct notifier_block *notifier)
+{
+	int ret;
+
+	if (IS_ERR_OR_NULL(qos) || !notifier)
+		return -EINVAL;
+
+	switch (type) {
+	case FREQ_QOS_MIN:
+		ret = blocking_notifier_chain_register(qos->min_freq.notifiers,
+						       notifier);
+		break;
+	case FREQ_QOS_MAX:
+		ret = blocking_notifier_chain_register(qos->max_freq.notifiers,
+						       notifier);
+		break;
+	default:
+		WARN_ON(1);
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(freq_qos_add_notifier);
+
+/**
+ * freq_qos_remove_notifier - Remove frequency QoS change notifier.
+ * @qos: List of requests to remove the notifier from.
+ * @type: Request type.
+ * @notifier: Notifier block to remove.
+ */
+int freq_qos_remove_notifier(struct freq_constraints *qos,
+			     enum freq_qos_req_type type,
+			     struct notifier_block *notifier)
+{
+	int ret;
+
+	if (IS_ERR_OR_NULL(qos) || !notifier)
+		return -EINVAL;
+
+	switch (type) {
+	case FREQ_QOS_MIN:
+		ret = blocking_notifier_chain_unregister(qos->min_freq.notifiers,
+							 notifier);
+		break;
+	case FREQ_QOS_MAX:
+		ret = blocking_notifier_chain_unregister(qos->max_freq.notifiers,
+							 notifier);
+		break;
+	default:
+		WARN_ON(1);
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(freq_qos_remove_notifier);
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
new file mode 100644
index 000000000..03c4ca404
--- /dev/null
+++ b/kernel/power/snapshot.c
@@ -0,0 +1,2756 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/kernel/power/snapshot.c
+ *
+ * This file provides system snapshot/restore functionality for swsusp.
+ *
+ * Copyright (C) 1998-2005 Pavel Machek <pavel@ucw.cz>
+ * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
+ */
+
+#define pr_fmt(fmt) "PM: hibernation: " fmt
+
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/suspend.h>
+#include <linux/delay.h>
+#include <linux/bitops.h>
+#include <linux/spinlock.h>
+#include <linux/kernel.h>
+#include <linux/pm.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/memblock.h>
+#include <linux/nmi.h>
+#include <linux/syscalls.h>
+#include <linux/console.h>
+#include <linux/highmem.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/compiler.h>
+#include <linux/ktime.h>
+#include <linux/set_memory.h>
+
+#include <linux/uaccess.h>
+#include <asm/mmu_context.h>
+#include <asm/tlbflush.h>
+#include <asm/io.h>
+
+#include "power.h"
+
+#if defined(CONFIG_STRICT_KERNEL_RWX) && defined(CONFIG_ARCH_HAS_SET_MEMORY)
+static bool hibernate_restore_protection;
+static bool hibernate_restore_protection_active;
+
+void enable_restore_image_protection(void)
+{
+	hibernate_restore_protection = true;
+}
+
+static inline void hibernate_restore_protection_begin(void)
+{
+	hibernate_restore_protection_active = hibernate_restore_protection;
+}
+
+static inline void hibernate_restore_protection_end(void)
+{
+	hibernate_restore_protection_active = false;
+}
+
+static inline void hibernate_restore_protect_page(void *page_address)
+{
+	if (hibernate_restore_protection_active)
+		set_memory_ro((unsigned long)page_address, 1);
+}
+
+static inline void hibernate_restore_unprotect_page(void *page_address)
+{
+	if (hibernate_restore_protection_active)
+		set_memory_rw((unsigned long)page_address, 1);
+}
+#else
+static inline void hibernate_restore_protection_begin(void) {}
+static inline void hibernate_restore_protection_end(void) {}
+static inline void hibernate_restore_protect_page(void *page_address) {}
+static inline void hibernate_restore_unprotect_page(void *page_address) {}
+#endif /* CONFIG_STRICT_KERNEL_RWX  && CONFIG_ARCH_HAS_SET_MEMORY */
+
+
+/*
+ * The calls to set_direct_map_*() should not fail because remapping a page
+ * here means that we only update protection bits in an existing PTE.
+ * It is still worth to have a warning here if something changes and this
+ * will no longer be the case.
+ */
+static inline void hibernate_map_page(struct page *page)
+{
+	if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) {
+		int ret = set_direct_map_default_noflush(page);
+
+		if (ret)
+			pr_warn_once("Failed to remap page\n");
+	} else {
+		debug_pagealloc_map_pages(page, 1);
+	}
+}
+
+static inline void hibernate_unmap_page(struct page *page)
+{
+	if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) {
+		unsigned long addr = (unsigned long)page_address(page);
+		int ret  = set_direct_map_invalid_noflush(page);
+
+		if (ret)
+			pr_warn_once("Failed to remap page\n");
+
+		flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
+	} else {
+		debug_pagealloc_unmap_pages(page, 1);
+	}
+}
+
+static int swsusp_page_is_free(struct page *);
+static void swsusp_set_page_forbidden(struct page *);
+static void swsusp_unset_page_forbidden(struct page *);
+
+/*
+ * Number of bytes to reserve for memory allocations made by device drivers
+ * from their ->freeze() and ->freeze_noirq() callbacks so that they don't
+ * cause image creation to fail (tunable via /sys/power/reserved_size).
+ */
+unsigned long reserved_size;
+
+void __init hibernate_reserved_size_init(void)
+{
+	reserved_size = SPARE_PAGES * PAGE_SIZE;
+}
+
+/*
+ * Preferred image size in bytes (tunable via /sys/power/image_size).
+ * When it is set to N, swsusp will do its best to ensure the image
+ * size will not exceed N bytes, but if that is impossible, it will
+ * try to create the smallest image possible.
+ */
+unsigned long image_size;
+
+void __init hibernate_image_size_init(void)
+{
+	image_size = ((totalram_pages() * 2) / 5) * PAGE_SIZE;
+}
+
+/*
+ * List of PBEs needed for restoring the pages that were allocated before
+ * the suspend and included in the suspend image, but have also been
+ * allocated by the "resume" kernel, so their contents cannot be written
+ * directly to their "original" page frames.
+ */
+struct pbe *restore_pblist;
+
+/* struct linked_page is used to build chains of pages */
+
+#define LINKED_PAGE_DATA_SIZE	(PAGE_SIZE - sizeof(void *))
+
+struct linked_page {
+	struct linked_page *next;
+	char data[LINKED_PAGE_DATA_SIZE];
+} __packed;
+
+/*
+ * List of "safe" pages (ie. pages that were not used by the image kernel
+ * before hibernation) that may be used as temporary storage for image kernel
+ * memory contents.
+ */
+static struct linked_page *safe_pages_list;
+
+/* Pointer to an auxiliary buffer (1 page) */
+static void *buffer;
+
+#define PG_ANY		0
+#define PG_SAFE		1
+#define PG_UNSAFE_CLEAR	1
+#define PG_UNSAFE_KEEP	0
+
+static unsigned int allocated_unsafe_pages;
+
+/**
+ * get_image_page - Allocate a page for a hibernation image.
+ * @gfp_mask: GFP mask for the allocation.
+ * @safe_needed: Get pages that were not used before hibernation (restore only)
+ *
+ * During image restoration, for storing the PBE list and the image data, we can
+ * only use memory pages that do not conflict with the pages used before
+ * hibernation.  The "unsafe" pages have PageNosaveFree set and we count them
+ * using allocated_unsafe_pages.
+ *
+ * Each allocated image page is marked as PageNosave and PageNosaveFree so that
+ * swsusp_free() can release it.
+ */
+static void *get_image_page(gfp_t gfp_mask, int safe_needed)
+{
+	void *res;
+
+	res = (void *)get_zeroed_page(gfp_mask);
+	if (safe_needed)
+		while (res && swsusp_page_is_free(virt_to_page(res))) {
+			/* The page is unsafe, mark it for swsusp_free() */
+			swsusp_set_page_forbidden(virt_to_page(res));
+			allocated_unsafe_pages++;
+			res = (void *)get_zeroed_page(gfp_mask);
+		}
+	if (res) {
+		swsusp_set_page_forbidden(virt_to_page(res));
+		swsusp_set_page_free(virt_to_page(res));
+	}
+	return res;
+}
+
+static void *__get_safe_page(gfp_t gfp_mask)
+{
+	if (safe_pages_list) {
+		void *ret = safe_pages_list;
+
+		safe_pages_list = safe_pages_list->next;
+		memset(ret, 0, PAGE_SIZE);
+		return ret;
+	}
+	return get_image_page(gfp_mask, PG_SAFE);
+}
+
+unsigned long get_safe_page(gfp_t gfp_mask)
+{
+	return (unsigned long)__get_safe_page(gfp_mask);
+}
+
+static struct page *alloc_image_page(gfp_t gfp_mask)
+{
+	struct page *page;
+
+	page = alloc_page(gfp_mask);
+	if (page) {
+		swsusp_set_page_forbidden(page);
+		swsusp_set_page_free(page);
+	}
+	return page;
+}
+
+static void recycle_safe_page(void *page_address)
+{
+	struct linked_page *lp = page_address;
+
+	lp->next = safe_pages_list;
+	safe_pages_list = lp;
+}
+
+/**
+ * free_image_page - Free a page allocated for hibernation image.
+ * @addr: Address of the page to free.
+ * @clear_nosave_free: If set, clear the PageNosaveFree bit for the page.
+ *
+ * The page to free should have been allocated by get_image_page() (page flags
+ * set by it are affected).
+ */
+static inline void free_image_page(void *addr, int clear_nosave_free)
+{
+	struct page *page;
+
+	BUG_ON(!virt_addr_valid(addr));
+
+	page = virt_to_page(addr);
+
+	swsusp_unset_page_forbidden(page);
+	if (clear_nosave_free)
+		swsusp_unset_page_free(page);
+
+	__free_page(page);
+}
+
+static inline void free_list_of_pages(struct linked_page *list,
+				      int clear_page_nosave)
+{
+	while (list) {
+		struct linked_page *lp = list->next;
+
+		free_image_page(list, clear_page_nosave);
+		list = lp;
+	}
+}
+
+/*
+ * struct chain_allocator is used for allocating small objects out of
+ * a linked list of pages called 'the chain'.
+ *
+ * The chain grows each time when there is no room for a new object in
+ * the current page.  The allocated objects cannot be freed individually.
+ * It is only possible to free them all at once, by freeing the entire
+ * chain.
+ *
+ * NOTE: The chain allocator may be inefficient if the allocated objects
+ * are not much smaller than PAGE_SIZE.
+ */
+struct chain_allocator {
+	struct linked_page *chain;	/* the chain */
+	unsigned int used_space;	/* total size of objects allocated out
+					   of the current page */
+	gfp_t gfp_mask;		/* mask for allocating pages */
+	int safe_needed;	/* if set, only "safe" pages are allocated */
+};
+
+static void chain_init(struct chain_allocator *ca, gfp_t gfp_mask,
+		       int safe_needed)
+{
+	ca->chain = NULL;
+	ca->used_space = LINKED_PAGE_DATA_SIZE;
+	ca->gfp_mask = gfp_mask;
+	ca->safe_needed = safe_needed;
+}
+
+static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
+{
+	void *ret;
+
+	if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
+		struct linked_page *lp;
+
+		lp = ca->safe_needed ? __get_safe_page(ca->gfp_mask) :
+					get_image_page(ca->gfp_mask, PG_ANY);
+		if (!lp)
+			return NULL;
+
+		lp->next = ca->chain;
+		ca->chain = lp;
+		ca->used_space = 0;
+	}
+	ret = ca->chain->data + ca->used_space;
+	ca->used_space += size;
+	return ret;
+}
+
+/*
+ * Data types related to memory bitmaps.
+ *
+ * Memory bitmap is a structure consisting of many linked lists of
+ * objects.  The main list's elements are of type struct zone_bitmap
+ * and each of them corresponds to one zone.  For each zone bitmap
+ * object there is a list of objects of type struct bm_block that
+ * represent each blocks of bitmap in which information is stored.
+ *
+ * struct memory_bitmap contains a pointer to the main list of zone
+ * bitmap objects, a struct bm_position used for browsing the bitmap,
+ * and a pointer to the list of pages used for allocating all of the
+ * zone bitmap objects and bitmap block objects.
+ *
+ * NOTE: It has to be possible to lay out the bitmap in memory
+ * using only allocations of order 0.  Additionally, the bitmap is
+ * designed to work with arbitrary number of zones (this is over the
+ * top for now, but let's avoid making unnecessary assumptions ;-).
+ *
+ * struct zone_bitmap contains a pointer to a list of bitmap block
+ * objects and a pointer to the bitmap block object that has been
+ * most recently used for setting bits.  Additionally, it contains the
+ * PFNs that correspond to the start and end of the represented zone.
+ *
+ * struct bm_block contains a pointer to the memory page in which
+ * information is stored (in the form of a block of bitmap)
+ * It also contains the pfns that correspond to the start and end of
+ * the represented memory area.
+ *
+ * The memory bitmap is organized as a radix tree to guarantee fast random
+ * access to the bits. There is one radix tree for each zone (as returned
+ * from create_mem_extents).
+ *
+ * One radix tree is represented by one struct mem_zone_bm_rtree. There are
+ * two linked lists for the nodes of the tree, one for the inner nodes and
+ * one for the leave nodes. The linked leave nodes are used for fast linear
+ * access of the memory bitmap.
+ *
+ * The struct rtree_node represents one node of the radix tree.
+ */
+
+#define BM_END_OF_MAP	(~0UL)
+
+#define BM_BITS_PER_BLOCK	(PAGE_SIZE * BITS_PER_BYTE)
+#define BM_BLOCK_SHIFT		(PAGE_SHIFT + 3)
+#define BM_BLOCK_MASK		((1UL << BM_BLOCK_SHIFT) - 1)
+
+/*
+ * struct rtree_node is a wrapper struct to link the nodes
+ * of the rtree together for easy linear iteration over
+ * bits and easy freeing
+ */
+struct rtree_node {
+	struct list_head list;
+	unsigned long *data;
+};
+
+/*
+ * struct mem_zone_bm_rtree represents a bitmap used for one
+ * populated memory zone.
+ */
+struct mem_zone_bm_rtree {
+	struct list_head list;		/* Link Zones together         */
+	struct list_head nodes;		/* Radix Tree inner nodes      */
+	struct list_head leaves;	/* Radix Tree leaves           */
+	unsigned long start_pfn;	/* Zone start page frame       */
+	unsigned long end_pfn;		/* Zone end page frame + 1     */
+	struct rtree_node *rtree;	/* Radix Tree Root             */
+	int levels;			/* Number of Radix Tree Levels */
+	unsigned int blocks;		/* Number of Bitmap Blocks     */
+};
+
+/* strcut bm_position is used for browsing memory bitmaps */
+
+struct bm_position {
+	struct mem_zone_bm_rtree *zone;
+	struct rtree_node *node;
+	unsigned long node_pfn;
+	int node_bit;
+};
+
+struct memory_bitmap {
+	struct list_head zones;
+	struct linked_page *p_list;	/* list of pages used to store zone
+					   bitmap objects and bitmap block
+					   objects */
+	struct bm_position cur;	/* most recently used bit position */
+};
+
+/* Functions that operate on memory bitmaps */
+
+#define BM_ENTRIES_PER_LEVEL	(PAGE_SIZE / sizeof(unsigned long))
+#if BITS_PER_LONG == 32
+#define BM_RTREE_LEVEL_SHIFT	(PAGE_SHIFT - 2)
+#else
+#define BM_RTREE_LEVEL_SHIFT	(PAGE_SHIFT - 3)
+#endif
+#define BM_RTREE_LEVEL_MASK	((1UL << BM_RTREE_LEVEL_SHIFT) - 1)
+
+/**
+ * alloc_rtree_node - Allocate a new node and add it to the radix tree.
+ * @gfp_mask: GFP mask for the allocation.
+ * @safe_needed: Get pages not used before hibernation (restore only)
+ * @ca: Pointer to a linked list of pages ("a chain") to allocate from
+ * @list: Radix Tree node to add.
+ *
+ * This function is used to allocate inner nodes as well as the
+ * leave nodes of the radix tree. It also adds the node to the
+ * corresponding linked list passed in by the *list parameter.
+ */
+static struct rtree_node *alloc_rtree_node(gfp_t gfp_mask, int safe_needed,
+					   struct chain_allocator *ca,
+					   struct list_head *list)
+{
+	struct rtree_node *node;
+
+	node = chain_alloc(ca, sizeof(struct rtree_node));
+	if (!node)
+		return NULL;
+
+	node->data = get_image_page(gfp_mask, safe_needed);
+	if (!node->data)
+		return NULL;
+
+	list_add_tail(&node->list, list);
+
+	return node;
+}
+
+/**
+ * add_rtree_block - Add a new leave node to the radix tree.
+ *
+ * The leave nodes need to be allocated in order to keep the leaves
+ * linked list in order. This is guaranteed by the zone->blocks
+ * counter.
+ */
+static int add_rtree_block(struct mem_zone_bm_rtree *zone, gfp_t gfp_mask,
+			   int safe_needed, struct chain_allocator *ca)
+{
+	struct rtree_node *node, *block, **dst;
+	unsigned int levels_needed, block_nr;
+	int i;
+
+	block_nr = zone->blocks;
+	levels_needed = 0;
+
+	/* How many levels do we need for this block nr? */
+	while (block_nr) {
+		levels_needed += 1;
+		block_nr >>= BM_RTREE_LEVEL_SHIFT;
+	}
+
+	/* Make sure the rtree has enough levels */
+	for (i = zone->levels; i < levels_needed; i++) {
+		node = alloc_rtree_node(gfp_mask, safe_needed, ca,
+					&zone->nodes);
+		if (!node)
+			return -ENOMEM;
+
+		node->data[0] = (unsigned long)zone->rtree;
+		zone->rtree = node;
+		zone->levels += 1;
+	}
+
+	/* Allocate new block */
+	block = alloc_rtree_node(gfp_mask, safe_needed, ca, &zone->leaves);
+	if (!block)
+		return -ENOMEM;
+
+	/* Now walk the rtree to insert the block */
+	node = zone->rtree;
+	dst = &zone->rtree;
+	block_nr = zone->blocks;
+	for (i = zone->levels; i > 0; i--) {
+		int index;
+
+		if (!node) {
+			node = alloc_rtree_node(gfp_mask, safe_needed, ca,
+						&zone->nodes);
+			if (!node)
+				return -ENOMEM;
+			*dst = node;
+		}
+
+		index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
+		index &= BM_RTREE_LEVEL_MASK;
+		dst = (struct rtree_node **)&((*dst)->data[index]);
+		node = *dst;
+	}
+
+	zone->blocks += 1;
+	*dst = block;
+
+	return 0;
+}
+
+static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
+			       int clear_nosave_free);
+
+/**
+ * create_zone_bm_rtree - Create a radix tree for one zone.
+ *
+ * Allocated the mem_zone_bm_rtree structure and initializes it.
+ * This function also allocated and builds the radix tree for the
+ * zone.
+ */
+static struct mem_zone_bm_rtree *create_zone_bm_rtree(gfp_t gfp_mask,
+						      int safe_needed,
+						      struct chain_allocator *ca,
+						      unsigned long start,
+						      unsigned long end)
+{
+	struct mem_zone_bm_rtree *zone;
+	unsigned int i, nr_blocks;
+	unsigned long pages;
+
+	pages = end - start;
+	zone  = chain_alloc(ca, sizeof(struct mem_zone_bm_rtree));
+	if (!zone)
+		return NULL;
+
+	INIT_LIST_HEAD(&zone->nodes);
+	INIT_LIST_HEAD(&zone->leaves);
+	zone->start_pfn = start;
+	zone->end_pfn = end;
+	nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
+
+	for (i = 0; i < nr_blocks; i++) {
+		if (add_rtree_block(zone, gfp_mask, safe_needed, ca)) {
+			free_zone_bm_rtree(zone, PG_UNSAFE_CLEAR);
+			return NULL;
+		}
+	}
+
+	return zone;
+}
+
+/**
+ * free_zone_bm_rtree - Free the memory of the radix tree.
+ *
+ * Free all node pages of the radix tree. The mem_zone_bm_rtree
+ * structure itself is not freed here nor are the rtree_node
+ * structs.
+ */
+static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
+			       int clear_nosave_free)
+{
+	struct rtree_node *node;
+
+	list_for_each_entry(node, &zone->nodes, list)
+		free_image_page(node->data, clear_nosave_free);
+
+	list_for_each_entry(node, &zone->leaves, list)
+		free_image_page(node->data, clear_nosave_free);
+}
+
+static void memory_bm_position_reset(struct memory_bitmap *bm)
+{
+	bm->cur.zone = list_entry(bm->zones.next, struct mem_zone_bm_rtree,
+				  list);
+	bm->cur.node = list_entry(bm->cur.zone->leaves.next,
+				  struct rtree_node, list);
+	bm->cur.node_pfn = 0;
+	bm->cur.node_bit = 0;
+}
+
+static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
+
+struct mem_extent {
+	struct list_head hook;
+	unsigned long start;
+	unsigned long end;
+};
+
+/**
+ * free_mem_extents - Free a list of memory extents.
+ * @list: List of extents to free.
+ */
+static void free_mem_extents(struct list_head *list)
+{
+	struct mem_extent *ext, *aux;
+
+	list_for_each_entry_safe(ext, aux, list, hook) {
+		list_del(&ext->hook);
+		kfree(ext);
+	}
+}
+
+/**
+ * create_mem_extents - Create a list of memory extents.
+ * @list: List to put the extents into.
+ * @gfp_mask: Mask to use for memory allocations.
+ *
+ * The extents represent contiguous ranges of PFNs.
+ */
+static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
+{
+	struct zone *zone;
+
+	INIT_LIST_HEAD(list);
+
+	for_each_populated_zone(zone) {
+		unsigned long zone_start, zone_end;
+		struct mem_extent *ext, *cur, *aux;
+
+		zone_start = zone->zone_start_pfn;
+		zone_end = zone_end_pfn(zone);
+
+		list_for_each_entry(ext, list, hook)
+			if (zone_start <= ext->end)
+				break;
+
+		if (&ext->hook == list || zone_end < ext->start) {
+			/* New extent is necessary */
+			struct mem_extent *new_ext;
+
+			new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask);
+			if (!new_ext) {
+				free_mem_extents(list);
+				return -ENOMEM;
+			}
+			new_ext->start = zone_start;
+			new_ext->end = zone_end;
+			list_add_tail(&new_ext->hook, &ext->hook);
+			continue;
+		}
+
+		/* Merge this zone's range of PFNs with the existing one */
+		if (zone_start < ext->start)
+			ext->start = zone_start;
+		if (zone_end > ext->end)
+			ext->end = zone_end;
+
+		/* More merging may be possible */
+		cur = ext;
+		list_for_each_entry_safe_continue(cur, aux, list, hook) {
+			if (zone_end < cur->start)
+				break;
+			if (zone_end < cur->end)
+				ext->end = cur->end;
+			list_del(&cur->hook);
+			kfree(cur);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * memory_bm_create - Allocate memory for a memory bitmap.
+ */
+static int memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask,
+			    int safe_needed)
+{
+	struct chain_allocator ca;
+	struct list_head mem_extents;
+	struct mem_extent *ext;
+	int error;
+
+	chain_init(&ca, gfp_mask, safe_needed);
+	INIT_LIST_HEAD(&bm->zones);
+
+	error = create_mem_extents(&mem_extents, gfp_mask);
+	if (error)
+		return error;
+
+	list_for_each_entry(ext, &mem_extents, hook) {
+		struct mem_zone_bm_rtree *zone;
+
+		zone = create_zone_bm_rtree(gfp_mask, safe_needed, &ca,
+					    ext->start, ext->end);
+		if (!zone) {
+			error = -ENOMEM;
+			goto Error;
+		}
+		list_add_tail(&zone->list, &bm->zones);
+	}
+
+	bm->p_list = ca.chain;
+	memory_bm_position_reset(bm);
+ Exit:
+	free_mem_extents(&mem_extents);
+	return error;
+
+ Error:
+	bm->p_list = ca.chain;
+	memory_bm_free(bm, PG_UNSAFE_CLEAR);
+	goto Exit;
+}
+
+/**
+ * memory_bm_free - Free memory occupied by the memory bitmap.
+ * @bm: Memory bitmap.
+ */
+static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
+{
+	struct mem_zone_bm_rtree *zone;
+
+	list_for_each_entry(zone, &bm->zones, list)
+		free_zone_bm_rtree(zone, clear_nosave_free);
+
+	free_list_of_pages(bm->p_list, clear_nosave_free);
+
+	INIT_LIST_HEAD(&bm->zones);
+}
+
+/**
+ * memory_bm_find_bit - Find the bit for a given PFN in a memory bitmap.
+ *
+ * Find the bit in memory bitmap @bm that corresponds to the given PFN.
+ * The cur.zone, cur.block and cur.node_pfn members of @bm are updated.
+ *
+ * Walk the radix tree to find the page containing the bit that represents @pfn
+ * and return the position of the bit in @addr and @bit_nr.
+ */
+static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
+			      void **addr, unsigned int *bit_nr)
+{
+	struct mem_zone_bm_rtree *curr, *zone;
+	struct rtree_node *node;
+	int i, block_nr;
+
+	zone = bm->cur.zone;
+
+	if (pfn >= zone->start_pfn && pfn < zone->end_pfn)
+		goto zone_found;
+
+	zone = NULL;
+
+	/* Find the right zone */
+	list_for_each_entry(curr, &bm->zones, list) {
+		if (pfn >= curr->start_pfn && pfn < curr->end_pfn) {
+			zone = curr;
+			break;
+		}
+	}
+
+	if (!zone)
+		return -EFAULT;
+
+zone_found:
+	/*
+	 * We have found the zone. Now walk the radix tree to find the leaf node
+	 * for our PFN.
+	 */
+
+	/*
+	 * If the zone we wish to scan is the current zone and the
+	 * pfn falls into the current node then we do not need to walk
+	 * the tree.
+	 */
+	node = bm->cur.node;
+	if (zone == bm->cur.zone &&
+	    ((pfn - zone->start_pfn) & ~BM_BLOCK_MASK) == bm->cur.node_pfn)
+		goto node_found;
+
+	node      = zone->rtree;
+	block_nr  = (pfn - zone->start_pfn) >> BM_BLOCK_SHIFT;
+
+	for (i = zone->levels; i > 0; i--) {
+		int index;
+
+		index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
+		index &= BM_RTREE_LEVEL_MASK;
+		BUG_ON(node->data[index] == 0);
+		node = (struct rtree_node *)node->data[index];
+	}
+
+node_found:
+	/* Update last position */
+	bm->cur.zone = zone;
+	bm->cur.node = node;
+	bm->cur.node_pfn = (pfn - zone->start_pfn) & ~BM_BLOCK_MASK;
+
+	/* Set return values */
+	*addr = node->data;
+	*bit_nr = (pfn - zone->start_pfn) & BM_BLOCK_MASK;
+
+	return 0;
+}
+
+static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
+{
+	void *addr;
+	unsigned int bit;
+	int error;
+
+	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
+	BUG_ON(error);
+	set_bit(bit, addr);
+}
+
+static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
+{
+	void *addr;
+	unsigned int bit;
+	int error;
+
+	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
+	if (!error)
+		set_bit(bit, addr);
+
+	return error;
+}
+
+static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
+{
+	void *addr;
+	unsigned int bit;
+	int error;
+
+	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
+	BUG_ON(error);
+	clear_bit(bit, addr);
+}
+
+static void memory_bm_clear_current(struct memory_bitmap *bm)
+{
+	int bit;
+
+	bit = max(bm->cur.node_bit - 1, 0);
+	clear_bit(bit, bm->cur.node->data);
+}
+
+static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
+{
+	void *addr;
+	unsigned int bit;
+	int error;
+
+	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
+	BUG_ON(error);
+	return test_bit(bit, addr);
+}
+
+static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
+{
+	void *addr;
+	unsigned int bit;
+
+	return !memory_bm_find_bit(bm, pfn, &addr, &bit);
+}
+
+/*
+ * rtree_next_node - Jump to the next leaf node.
+ *
+ * Set the position to the beginning of the next node in the
+ * memory bitmap. This is either the next node in the current
+ * zone's radix tree or the first node in the radix tree of the
+ * next zone.
+ *
+ * Return true if there is a next node, false otherwise.
+ */
+static bool rtree_next_node(struct memory_bitmap *bm)
+{
+	if (!list_is_last(&bm->cur.node->list, &bm->cur.zone->leaves)) {
+		bm->cur.node = list_entry(bm->cur.node->list.next,
+					  struct rtree_node, list);
+		bm->cur.node_pfn += BM_BITS_PER_BLOCK;
+		bm->cur.node_bit  = 0;
+		touch_softlockup_watchdog();
+		return true;
+	}
+
+	/* No more nodes, goto next zone */
+	if (!list_is_last(&bm->cur.zone->list, &bm->zones)) {
+		bm->cur.zone = list_entry(bm->cur.zone->list.next,
+				  struct mem_zone_bm_rtree, list);
+		bm->cur.node = list_entry(bm->cur.zone->leaves.next,
+					  struct rtree_node, list);
+		bm->cur.node_pfn = 0;
+		bm->cur.node_bit = 0;
+		return true;
+	}
+
+	/* No more zones */
+	return false;
+}
+
+/**
+ * memory_bm_next_pfn - Find the next set bit in a memory bitmap.
+ * @bm: Memory bitmap.
+ *
+ * Starting from the last returned position this function searches for the next
+ * set bit in @bm and returns the PFN represented by it.  If no more bits are
+ * set, BM_END_OF_MAP is returned.
+ *
+ * It is required to run memory_bm_position_reset() before the first call to
+ * this function for the given memory bitmap.
+ */
+static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
+{
+	unsigned long bits, pfn, pages;
+	int bit;
+
+	do {
+		pages	  = bm->cur.zone->end_pfn - bm->cur.zone->start_pfn;
+		bits      = min(pages - bm->cur.node_pfn, BM_BITS_PER_BLOCK);
+		bit	  = find_next_bit(bm->cur.node->data, bits,
+					  bm->cur.node_bit);
+		if (bit < bits) {
+			pfn = bm->cur.zone->start_pfn + bm->cur.node_pfn + bit;
+			bm->cur.node_bit = bit + 1;
+			return pfn;
+		}
+	} while (rtree_next_node(bm));
+
+	return BM_END_OF_MAP;
+}
+
+/*
+ * This structure represents a range of page frames the contents of which
+ * should not be saved during hibernation.
+ */
+struct nosave_region {
+	struct list_head list;
+	unsigned long start_pfn;
+	unsigned long end_pfn;
+};
+
+static LIST_HEAD(nosave_regions);
+
+static void recycle_zone_bm_rtree(struct mem_zone_bm_rtree *zone)
+{
+	struct rtree_node *node;
+
+	list_for_each_entry(node, &zone->nodes, list)
+		recycle_safe_page(node->data);
+
+	list_for_each_entry(node, &zone->leaves, list)
+		recycle_safe_page(node->data);
+}
+
+static void memory_bm_recycle(struct memory_bitmap *bm)
+{
+	struct mem_zone_bm_rtree *zone;
+	struct linked_page *p_list;
+
+	list_for_each_entry(zone, &bm->zones, list)
+		recycle_zone_bm_rtree(zone);
+
+	p_list = bm->p_list;
+	while (p_list) {
+		struct linked_page *lp = p_list;
+
+		p_list = lp->next;
+		recycle_safe_page(lp);
+	}
+}
+
+/**
+ * register_nosave_region - Register a region of unsaveable memory.
+ *
+ * Register a range of page frames the contents of which should not be saved
+ * during hibernation (to be used in the early initialization code).
+ */
+void __init register_nosave_region(unsigned long start_pfn, unsigned long end_pfn)
+{
+	struct nosave_region *region;
+
+	if (start_pfn >= end_pfn)
+		return;
+
+	if (!list_empty(&nosave_regions)) {
+		/* Try to extend the previous region (they should be sorted) */
+		region = list_entry(nosave_regions.prev,
+					struct nosave_region, list);
+		if (region->end_pfn == start_pfn) {
+			region->end_pfn = end_pfn;
+			goto Report;
+		}
+	}
+	/* This allocation cannot fail */
+	region = memblock_alloc(sizeof(struct nosave_region),
+				SMP_CACHE_BYTES);
+	if (!region)
+		panic("%s: Failed to allocate %zu bytes\n", __func__,
+		      sizeof(struct nosave_region));
+	region->start_pfn = start_pfn;
+	region->end_pfn = end_pfn;
+	list_add_tail(&region->list, &nosave_regions);
+ Report:
+	pr_info("Registered nosave memory: [mem %#010llx-%#010llx]\n",
+		(unsigned long long) start_pfn << PAGE_SHIFT,
+		((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
+}
+
+/*
+ * Set bits in this map correspond to the page frames the contents of which
+ * should not be saved during the suspend.
+ */
+static struct memory_bitmap *forbidden_pages_map;
+
+/* Set bits in this map correspond to free page frames. */
+static struct memory_bitmap *free_pages_map;
+
+/*
+ * Each page frame allocated for creating the image is marked by setting the
+ * corresponding bits in forbidden_pages_map and free_pages_map simultaneously
+ */
+
+void swsusp_set_page_free(struct page *page)
+{
+	if (free_pages_map)
+		memory_bm_set_bit(free_pages_map, page_to_pfn(page));
+}
+
+static int swsusp_page_is_free(struct page *page)
+{
+	return free_pages_map ?
+		memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0;
+}
+
+void swsusp_unset_page_free(struct page *page)
+{
+	if (free_pages_map)
+		memory_bm_clear_bit(free_pages_map, page_to_pfn(page));
+}
+
+static void swsusp_set_page_forbidden(struct page *page)
+{
+	if (forbidden_pages_map)
+		memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page));
+}
+
+int swsusp_page_is_forbidden(struct page *page)
+{
+	return forbidden_pages_map ?
+		memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0;
+}
+
+static void swsusp_unset_page_forbidden(struct page *page)
+{
+	if (forbidden_pages_map)
+		memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page));
+}
+
+/**
+ * mark_nosave_pages - Mark pages that should not be saved.
+ * @bm: Memory bitmap.
+ *
+ * Set the bits in @bm that correspond to the page frames the contents of which
+ * should not be saved.
+ */
+static void mark_nosave_pages(struct memory_bitmap *bm)
+{
+	struct nosave_region *region;
+
+	if (list_empty(&nosave_regions))
+		return;
+
+	list_for_each_entry(region, &nosave_regions, list) {
+		unsigned long pfn;
+
+		pr_debug("Marking nosave pages: [mem %#010llx-%#010llx]\n",
+			 (unsigned long long) region->start_pfn << PAGE_SHIFT,
+			 ((unsigned long long) region->end_pfn << PAGE_SHIFT)
+				- 1);
+
+		for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)
+			if (pfn_valid(pfn)) {
+				/*
+				 * It is safe to ignore the result of
+				 * mem_bm_set_bit_check() here, since we won't
+				 * touch the PFNs for which the error is
+				 * returned anyway.
+				 */
+				mem_bm_set_bit_check(bm, pfn);
+			}
+	}
+}
+
+/**
+ * create_basic_memory_bitmaps - Create bitmaps to hold basic page information.
+ *
+ * Create bitmaps needed for marking page frames that should not be saved and
+ * free page frames.  The forbidden_pages_map and free_pages_map pointers are
+ * only modified if everything goes well, because we don't want the bits to be
+ * touched before both bitmaps are set up.
+ */
+int create_basic_memory_bitmaps(void)
+{
+	struct memory_bitmap *bm1, *bm2;
+	int error = 0;
+
+	if (forbidden_pages_map && free_pages_map)
+		return 0;
+	else
+		BUG_ON(forbidden_pages_map || free_pages_map);
+
+	bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
+	if (!bm1)
+		return -ENOMEM;
+
+	error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY);
+	if (error)
+		goto Free_first_object;
+
+	bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
+	if (!bm2)
+		goto Free_first_bitmap;
+
+	error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY);
+	if (error)
+		goto Free_second_object;
+
+	forbidden_pages_map = bm1;
+	free_pages_map = bm2;
+	mark_nosave_pages(forbidden_pages_map);
+
+	pr_debug("Basic memory bitmaps created\n");
+
+	return 0;
+
+ Free_second_object:
+	kfree(bm2);
+ Free_first_bitmap:
+	memory_bm_free(bm1, PG_UNSAFE_CLEAR);
+ Free_first_object:
+	kfree(bm1);
+	return -ENOMEM;
+}
+
+/**
+ * free_basic_memory_bitmaps - Free memory bitmaps holding basic information.
+ *
+ * Free memory bitmaps allocated by create_basic_memory_bitmaps().  The
+ * auxiliary pointers are necessary so that the bitmaps themselves are not
+ * referred to while they are being freed.
+ */
+void free_basic_memory_bitmaps(void)
+{
+	struct memory_bitmap *bm1, *bm2;
+
+	if (WARN_ON(!(forbidden_pages_map && free_pages_map)))
+		return;
+
+	bm1 = forbidden_pages_map;
+	bm2 = free_pages_map;
+	forbidden_pages_map = NULL;
+	free_pages_map = NULL;
+	memory_bm_free(bm1, PG_UNSAFE_CLEAR);
+	kfree(bm1);
+	memory_bm_free(bm2, PG_UNSAFE_CLEAR);
+	kfree(bm2);
+
+	pr_debug("Basic memory bitmaps freed\n");
+}
+
+static void clear_or_poison_free_page(struct page *page)
+{
+	if (page_poisoning_enabled_static())
+		__kernel_poison_pages(page, 1);
+	else if (want_init_on_free())
+		clear_highpage(page);
+}
+
+void clear_or_poison_free_pages(void)
+{
+	struct memory_bitmap *bm = free_pages_map;
+	unsigned long pfn;
+
+	if (WARN_ON(!(free_pages_map)))
+		return;
+
+	if (page_poisoning_enabled() || want_init_on_free()) {
+		memory_bm_position_reset(bm);
+		pfn = memory_bm_next_pfn(bm);
+		while (pfn != BM_END_OF_MAP) {
+			if (pfn_valid(pfn))
+				clear_or_poison_free_page(pfn_to_page(pfn));
+
+			pfn = memory_bm_next_pfn(bm);
+		}
+		memory_bm_position_reset(bm);
+		pr_info("free pages cleared after restore\n");
+	}
+}
+
+/**
+ * snapshot_additional_pages - Estimate the number of extra pages needed.
+ * @zone: Memory zone to carry out the computation for.
+ *
+ * Estimate the number of additional pages needed for setting up a hibernation
+ * image data structures for @zone (usually, the returned value is greater than
+ * the exact number).
+ */
+unsigned int snapshot_additional_pages(struct zone *zone)
+{
+	unsigned int rtree, nodes;
+
+	rtree = nodes = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
+	rtree += DIV_ROUND_UP(rtree * sizeof(struct rtree_node),
+			      LINKED_PAGE_DATA_SIZE);
+	while (nodes > 1) {
+		nodes = DIV_ROUND_UP(nodes, BM_ENTRIES_PER_LEVEL);
+		rtree += nodes;
+	}
+
+	return 2 * rtree;
+}
+
+#ifdef CONFIG_HIGHMEM
+/**
+ * count_free_highmem_pages - Compute the total number of free highmem pages.
+ *
+ * The returned number is system-wide.
+ */
+static unsigned int count_free_highmem_pages(void)
+{
+	struct zone *zone;
+	unsigned int cnt = 0;
+
+	for_each_populated_zone(zone)
+		if (is_highmem(zone))
+			cnt += zone_page_state(zone, NR_FREE_PAGES);
+
+	return cnt;
+}
+
+/**
+ * saveable_highmem_page - Check if a highmem page is saveable.
+ *
+ * Determine whether a highmem page should be included in a hibernation image.
+ *
+ * We should save the page if it isn't Nosave or NosaveFree, or Reserved,
+ * and it isn't part of a free chunk of pages.
+ */
+static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
+{
+	struct page *page;
+
+	if (!pfn_valid(pfn))
+		return NULL;
+
+	page = pfn_to_online_page(pfn);
+	if (!page || page_zone(page) != zone)
+		return NULL;
+
+	BUG_ON(!PageHighMem(page));
+
+	if (swsusp_page_is_forbidden(page) ||  swsusp_page_is_free(page))
+		return NULL;
+
+	if (PageReserved(page) || PageOffline(page))
+		return NULL;
+
+	if (page_is_guard(page))
+		return NULL;
+
+	return page;
+}
+
+/**
+ * count_highmem_pages - Compute the total number of saveable highmem pages.
+ */
+static unsigned int count_highmem_pages(void)
+{
+	struct zone *zone;
+	unsigned int n = 0;
+
+	for_each_populated_zone(zone) {
+		unsigned long pfn, max_zone_pfn;
+
+		if (!is_highmem(zone))
+			continue;
+
+		mark_free_pages(zone);
+		max_zone_pfn = zone_end_pfn(zone);
+		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
+			if (saveable_highmem_page(zone, pfn))
+				n++;
+	}
+	return n;
+}
+#else
+static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
+{
+	return NULL;
+}
+#endif /* CONFIG_HIGHMEM */
+
+/**
+ * saveable_page - Check if the given page is saveable.
+ *
+ * Determine whether a non-highmem page should be included in a hibernation
+ * image.
+ *
+ * We should save the page if it isn't Nosave, and is not in the range
+ * of pages statically defined as 'unsaveable', and it isn't part of
+ * a free chunk of pages.
+ */
+static struct page *saveable_page(struct zone *zone, unsigned long pfn)
+{
+	struct page *page;
+
+	if (!pfn_valid(pfn))
+		return NULL;
+
+	page = pfn_to_online_page(pfn);
+	if (!page || page_zone(page) != zone)
+		return NULL;
+
+	BUG_ON(PageHighMem(page));
+
+	if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
+		return NULL;
+
+	if (PageOffline(page))
+		return NULL;
+
+	if (PageReserved(page)
+	    && (!kernel_page_present(page) || pfn_is_nosave(pfn)))
+		return NULL;
+
+	if (page_is_guard(page))
+		return NULL;
+
+	return page;
+}
+
+/**
+ * count_data_pages - Compute the total number of saveable non-highmem pages.
+ */
+static unsigned int count_data_pages(void)
+{
+	struct zone *zone;
+	unsigned long pfn, max_zone_pfn;
+	unsigned int n = 0;
+
+	for_each_populated_zone(zone) {
+		if (is_highmem(zone))
+			continue;
+
+		mark_free_pages(zone);
+		max_zone_pfn = zone_end_pfn(zone);
+		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
+			if (saveable_page(zone, pfn))
+				n++;
+	}
+	return n;
+}
+
+/*
+ * This is needed, because copy_page and memcpy are not usable for copying
+ * task structs.
+ */
+static inline void do_copy_page(long *dst, long *src)
+{
+	int n;
+
+	for (n = PAGE_SIZE / sizeof(long); n; n--)
+		*dst++ = *src++;
+}
+
+/**
+ * safe_copy_page - Copy a page in a safe way.
+ *
+ * Check if the page we are going to copy is marked as present in the kernel
+ * page tables. This always is the case if CONFIG_DEBUG_PAGEALLOC or
+ * CONFIG_ARCH_HAS_SET_DIRECT_MAP is not set. In that case kernel_page_present()
+ * always returns 'true'.
+ */
+static void safe_copy_page(void *dst, struct page *s_page)
+{
+	if (kernel_page_present(s_page)) {
+		do_copy_page(dst, page_address(s_page));
+	} else {
+		hibernate_map_page(s_page);
+		do_copy_page(dst, page_address(s_page));
+		hibernate_unmap_page(s_page);
+	}
+}
+
+#ifdef CONFIG_HIGHMEM
+static inline struct page *page_is_saveable(struct zone *zone, unsigned long pfn)
+{
+	return is_highmem(zone) ?
+		saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);
+}
+
+static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
+{
+	struct page *s_page, *d_page;
+	void *src, *dst;
+
+	s_page = pfn_to_page(src_pfn);
+	d_page = pfn_to_page(dst_pfn);
+	if (PageHighMem(s_page)) {
+		src = kmap_atomic(s_page);
+		dst = kmap_atomic(d_page);
+		do_copy_page(dst, src);
+		kunmap_atomic(dst);
+		kunmap_atomic(src);
+	} else {
+		if (PageHighMem(d_page)) {
+			/*
+			 * The page pointed to by src may contain some kernel
+			 * data modified by kmap_atomic()
+			 */
+			safe_copy_page(buffer, s_page);
+			dst = kmap_atomic(d_page);
+			copy_page(dst, buffer);
+			kunmap_atomic(dst);
+		} else {
+			safe_copy_page(page_address(d_page), s_page);
+		}
+	}
+}
+#else
+#define page_is_saveable(zone, pfn)	saveable_page(zone, pfn)
+
+static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
+{
+	safe_copy_page(page_address(pfn_to_page(dst_pfn)),
+				pfn_to_page(src_pfn));
+}
+#endif /* CONFIG_HIGHMEM */
+
+static void copy_data_pages(struct memory_bitmap *copy_bm,
+			    struct memory_bitmap *orig_bm)
+{
+	struct zone *zone;
+	unsigned long pfn;
+
+	for_each_populated_zone(zone) {
+		unsigned long max_zone_pfn;
+
+		mark_free_pages(zone);
+		max_zone_pfn = zone_end_pfn(zone);
+		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
+			if (page_is_saveable(zone, pfn))
+				memory_bm_set_bit(orig_bm, pfn);
+	}
+	memory_bm_position_reset(orig_bm);
+	memory_bm_position_reset(copy_bm);
+	for(;;) {
+		pfn = memory_bm_next_pfn(orig_bm);
+		if (unlikely(pfn == BM_END_OF_MAP))
+			break;
+		copy_data_page(memory_bm_next_pfn(copy_bm), pfn);
+	}
+}
+
+/* Total number of image pages */
+static unsigned int nr_copy_pages;
+/* Number of pages needed for saving the original pfns of the image pages */
+static unsigned int nr_meta_pages;
+/*
+ * Numbers of normal and highmem page frames allocated for hibernation image
+ * before suspending devices.
+ */
+static unsigned int alloc_normal, alloc_highmem;
+/*
+ * Memory bitmap used for marking saveable pages (during hibernation) or
+ * hibernation image pages (during restore)
+ */
+static struct memory_bitmap orig_bm;
+/*
+ * Memory bitmap used during hibernation for marking allocated page frames that
+ * will contain copies of saveable pages.  During restore it is initially used
+ * for marking hibernation image pages, but then the set bits from it are
+ * duplicated in @orig_bm and it is released.  On highmem systems it is next
+ * used for marking "safe" highmem pages, but it has to be reinitialized for
+ * this purpose.
+ */
+static struct memory_bitmap copy_bm;
+
+/**
+ * swsusp_free - Free pages allocated for hibernation image.
+ *
+ * Image pages are allocated before snapshot creation, so they need to be
+ * released after resume.
+ */
+void swsusp_free(void)
+{
+	unsigned long fb_pfn, fr_pfn;
+
+	if (!forbidden_pages_map || !free_pages_map)
+		goto out;
+
+	memory_bm_position_reset(forbidden_pages_map);
+	memory_bm_position_reset(free_pages_map);
+
+loop:
+	fr_pfn = memory_bm_next_pfn(free_pages_map);
+	fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
+
+	/*
+	 * Find the next bit set in both bitmaps. This is guaranteed to
+	 * terminate when fb_pfn == fr_pfn == BM_END_OF_MAP.
+	 */
+	do {
+		if (fb_pfn < fr_pfn)
+			fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
+		if (fr_pfn < fb_pfn)
+			fr_pfn = memory_bm_next_pfn(free_pages_map);
+	} while (fb_pfn != fr_pfn);
+
+	if (fr_pfn != BM_END_OF_MAP && pfn_valid(fr_pfn)) {
+		struct page *page = pfn_to_page(fr_pfn);
+
+		memory_bm_clear_current(forbidden_pages_map);
+		memory_bm_clear_current(free_pages_map);
+		hibernate_restore_unprotect_page(page_address(page));
+		__free_page(page);
+		goto loop;
+	}
+
+out:
+	nr_copy_pages = 0;
+	nr_meta_pages = 0;
+	restore_pblist = NULL;
+	buffer = NULL;
+	alloc_normal = 0;
+	alloc_highmem = 0;
+	hibernate_restore_protection_end();
+}
+
+/* Helper functions used for the shrinking of memory. */
+
+#define GFP_IMAGE	(GFP_KERNEL | __GFP_NOWARN)
+
+/**
+ * preallocate_image_pages - Allocate a number of pages for hibernation image.
+ * @nr_pages: Number of page frames to allocate.
+ * @mask: GFP flags to use for the allocation.
+ *
+ * Return value: Number of page frames actually allocated
+ */
+static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask)
+{
+	unsigned long nr_alloc = 0;
+
+	while (nr_pages > 0) {
+		struct page *page;
+
+		page = alloc_image_page(mask);
+		if (!page)
+			break;
+		memory_bm_set_bit(&copy_bm, page_to_pfn(page));
+		if (PageHighMem(page))
+			alloc_highmem++;
+		else
+			alloc_normal++;
+		nr_pages--;
+		nr_alloc++;
+	}
+
+	return nr_alloc;
+}
+
+static unsigned long preallocate_image_memory(unsigned long nr_pages,
+					      unsigned long avail_normal)
+{
+	unsigned long alloc;
+
+	if (avail_normal <= alloc_normal)
+		return 0;
+
+	alloc = avail_normal - alloc_normal;
+	if (nr_pages < alloc)
+		alloc = nr_pages;
+
+	return preallocate_image_pages(alloc, GFP_IMAGE);
+}
+
+#ifdef CONFIG_HIGHMEM
+static unsigned long preallocate_image_highmem(unsigned long nr_pages)
+{
+	return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM);
+}
+
+/**
+ *  __fraction - Compute (an approximation of) x * (multiplier / base).
+ */
+static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
+{
+	return div64_u64(x * multiplier, base);
+}
+
+static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
+						  unsigned long highmem,
+						  unsigned long total)
+{
+	unsigned long alloc = __fraction(nr_pages, highmem, total);
+
+	return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM);
+}
+#else /* CONFIG_HIGHMEM */
+static inline unsigned long preallocate_image_highmem(unsigned long nr_pages)
+{
+	return 0;
+}
+
+static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
+							 unsigned long highmem,
+							 unsigned long total)
+{
+	return 0;
+}
+#endif /* CONFIG_HIGHMEM */
+
+/**
+ * free_unnecessary_pages - Release preallocated pages not needed for the image.
+ */
+static unsigned long free_unnecessary_pages(void)
+{
+	unsigned long save, to_free_normal, to_free_highmem, free;
+
+	save = count_data_pages();
+	if (alloc_normal >= save) {
+		to_free_normal = alloc_normal - save;
+		save = 0;
+	} else {
+		to_free_normal = 0;
+		save -= alloc_normal;
+	}
+	save += count_highmem_pages();
+	if (alloc_highmem >= save) {
+		to_free_highmem = alloc_highmem - save;
+	} else {
+		to_free_highmem = 0;
+		save -= alloc_highmem;
+		if (to_free_normal > save)
+			to_free_normal -= save;
+		else
+			to_free_normal = 0;
+	}
+	free = to_free_normal + to_free_highmem;
+
+	memory_bm_position_reset(&copy_bm);
+
+	while (to_free_normal > 0 || to_free_highmem > 0) {
+		unsigned long pfn = memory_bm_next_pfn(&copy_bm);
+		struct page *page = pfn_to_page(pfn);
+
+		if (PageHighMem(page)) {
+			if (!to_free_highmem)
+				continue;
+			to_free_highmem--;
+			alloc_highmem--;
+		} else {
+			if (!to_free_normal)
+				continue;
+			to_free_normal--;
+			alloc_normal--;
+		}
+		memory_bm_clear_bit(&copy_bm, pfn);
+		swsusp_unset_page_forbidden(page);
+		swsusp_unset_page_free(page);
+		__free_page(page);
+	}
+
+	return free;
+}
+
+/**
+ * minimum_image_size - Estimate the minimum acceptable size of an image.
+ * @saveable: Number of saveable pages in the system.
+ *
+ * We want to avoid attempting to free too much memory too hard, so estimate the
+ * minimum acceptable size of a hibernation image to use as the lower limit for
+ * preallocating memory.
+ *
+ * We assume that the minimum image size should be proportional to
+ *
+ * [number of saveable pages] - [number of pages that can be freed in theory]
+ *
+ * where the second term is the sum of (1) reclaimable slab pages, (2) active
+ * and (3) inactive anonymous pages, (4) active and (5) inactive file pages.
+ */
+static unsigned long minimum_image_size(unsigned long saveable)
+{
+	unsigned long size;
+
+	size = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B)
+		+ global_node_page_state(NR_ACTIVE_ANON)
+		+ global_node_page_state(NR_INACTIVE_ANON)
+		+ global_node_page_state(NR_ACTIVE_FILE)
+		+ global_node_page_state(NR_INACTIVE_FILE);
+
+	return saveable <= size ? 0 : saveable - size;
+}
+
+/**
+ * hibernate_preallocate_memory - Preallocate memory for hibernation image.
+ *
+ * To create a hibernation image it is necessary to make a copy of every page
+ * frame in use.  We also need a number of page frames to be free during
+ * hibernation for allocations made while saving the image and for device
+ * drivers, in case they need to allocate memory from their hibernation
+ * callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough
+ * estimate) and reserved_size divided by PAGE_SIZE (which is tunable through
+ * /sys/power/reserved_size, respectively).  To make this happen, we compute the
+ * total number of available page frames and allocate at least
+ *
+ * ([page frames total] - PAGES_FOR_IO - [metadata pages]) / 2
+ *  - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE)
+ *
+ * of them, which corresponds to the maximum size of a hibernation image.
+ *
+ * If image_size is set below the number following from the above formula,
+ * the preallocation of memory is continued until the total number of saveable
+ * pages in the system is below the requested image size or the minimum
+ * acceptable image size returned by minimum_image_size(), whichever is greater.
+ */
+int hibernate_preallocate_memory(void)
+{
+	struct zone *zone;
+	unsigned long saveable, size, max_size, count, highmem, pages = 0;
+	unsigned long alloc, save_highmem, pages_highmem, avail_normal;
+	ktime_t start, stop;
+	int error;
+
+	pr_info("Preallocating image memory\n");
+	start = ktime_get();
+
+	error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
+	if (error) {
+		pr_err("Cannot allocate original bitmap\n");
+		goto err_out;
+	}
+
+	error = memory_bm_create(&copy_bm, GFP_IMAGE, PG_ANY);
+	if (error) {
+		pr_err("Cannot allocate copy bitmap\n");
+		goto err_out;
+	}
+
+	alloc_normal = 0;
+	alloc_highmem = 0;
+
+	/* Count the number of saveable data pages. */
+	save_highmem = count_highmem_pages();
+	saveable = count_data_pages();
+
+	/*
+	 * Compute the total number of page frames we can use (count) and the
+	 * number of pages needed for image metadata (size).
+	 */
+	count = saveable;
+	saveable += save_highmem;
+	highmem = save_highmem;
+	size = 0;
+	for_each_populated_zone(zone) {
+		size += snapshot_additional_pages(zone);
+		if (is_highmem(zone))
+			highmem += zone_page_state(zone, NR_FREE_PAGES);
+		else
+			count += zone_page_state(zone, NR_FREE_PAGES);
+	}
+	avail_normal = count;
+	count += highmem;
+	count -= totalreserve_pages;
+
+	/* Compute the maximum number of saveable pages to leave in memory. */
+	max_size = (count - (size + PAGES_FOR_IO)) / 2
+			- 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE);
+	/* Compute the desired number of image pages specified by image_size. */
+	size = DIV_ROUND_UP(image_size, PAGE_SIZE);
+	if (size > max_size)
+		size = max_size;
+	/*
+	 * If the desired number of image pages is at least as large as the
+	 * current number of saveable pages in memory, allocate page frames for
+	 * the image and we're done.
+	 */
+	if (size >= saveable) {
+		pages = preallocate_image_highmem(save_highmem);
+		pages += preallocate_image_memory(saveable - pages, avail_normal);
+		goto out;
+	}
+
+	/* Estimate the minimum size of the image. */
+	pages = minimum_image_size(saveable);
+	/*
+	 * To avoid excessive pressure on the normal zone, leave room in it to
+	 * accommodate an image of the minimum size (unless it's already too
+	 * small, in which case don't preallocate pages from it at all).
+	 */
+	if (avail_normal > pages)
+		avail_normal -= pages;
+	else
+		avail_normal = 0;
+	if (size < pages)
+		size = min_t(unsigned long, pages, max_size);
+
+	/*
+	 * Let the memory management subsystem know that we're going to need a
+	 * large number of page frames to allocate and make it free some memory.
+	 * NOTE: If this is not done, performance will be hurt badly in some
+	 * test cases.
+	 */
+	shrink_all_memory(saveable - size);
+
+	/*
+	 * The number of saveable pages in memory was too high, so apply some
+	 * pressure to decrease it.  First, make room for the largest possible
+	 * image and fail if that doesn't work.  Next, try to decrease the size
+	 * of the image as much as indicated by 'size' using allocations from
+	 * highmem and non-highmem zones separately.
+	 */
+	pages_highmem = preallocate_image_highmem(highmem / 2);
+	alloc = count - max_size;
+	if (alloc > pages_highmem)
+		alloc -= pages_highmem;
+	else
+		alloc = 0;
+	pages = preallocate_image_memory(alloc, avail_normal);
+	if (pages < alloc) {
+		/* We have exhausted non-highmem pages, try highmem. */
+		alloc -= pages;
+		pages += pages_highmem;
+		pages_highmem = preallocate_image_highmem(alloc);
+		if (pages_highmem < alloc) {
+			pr_err("Image allocation is %lu pages short\n",
+				alloc - pages_highmem);
+			goto err_out;
+		}
+		pages += pages_highmem;
+		/*
+		 * size is the desired number of saveable pages to leave in
+		 * memory, so try to preallocate (all memory - size) pages.
+		 */
+		alloc = (count - pages) - size;
+		pages += preallocate_image_highmem(alloc);
+	} else {
+		/*
+		 * There are approximately max_size saveable pages at this point
+		 * and we want to reduce this number down to size.
+		 */
+		alloc = max_size - size;
+		size = preallocate_highmem_fraction(alloc, highmem, count);
+		pages_highmem += size;
+		alloc -= size;
+		size = preallocate_image_memory(alloc, avail_normal);
+		pages_highmem += preallocate_image_highmem(alloc - size);
+		pages += pages_highmem + size;
+	}
+
+	/*
+	 * We only need as many page frames for the image as there are saveable
+	 * pages in memory, but we have allocated more.  Release the excessive
+	 * ones now.
+	 */
+	pages -= free_unnecessary_pages();
+
+ out:
+	stop = ktime_get();
+	pr_info("Allocated %lu pages for snapshot\n", pages);
+	swsusp_show_speed(start, stop, pages, "Allocated");
+
+	return 0;
+
+ err_out:
+	swsusp_free();
+	return -ENOMEM;
+}
+
+#ifdef CONFIG_HIGHMEM
+/**
+ * count_pages_for_highmem - Count non-highmem pages needed for copying highmem.
+ *
+ * Compute the number of non-highmem pages that will be necessary for creating
+ * copies of highmem pages.
+ */
+static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
+{
+	unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem;
+
+	if (free_highmem >= nr_highmem)
+		nr_highmem = 0;
+	else
+		nr_highmem -= free_highmem;
+
+	return nr_highmem;
+}
+#else
+static unsigned int count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
+#endif /* CONFIG_HIGHMEM */
+
+/**
+ * enough_free_mem - Check if there is enough free memory for the image.
+ */
+static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
+{
+	struct zone *zone;
+	unsigned int free = alloc_normal;
+
+	for_each_populated_zone(zone)
+		if (!is_highmem(zone))
+			free += zone_page_state(zone, NR_FREE_PAGES);
+
+	nr_pages += count_pages_for_highmem(nr_highmem);
+	pr_debug("Normal pages needed: %u + %u, available pages: %u\n",
+		 nr_pages, PAGES_FOR_IO, free);
+
+	return free > nr_pages + PAGES_FOR_IO;
+}
+
+#ifdef CONFIG_HIGHMEM
+/**
+ * get_highmem_buffer - Allocate a buffer for highmem pages.
+ *
+ * If there are some highmem pages in the hibernation image, we may need a
+ * buffer to copy them and/or load their data.
+ */
+static inline int get_highmem_buffer(int safe_needed)
+{
+	buffer = get_image_page(GFP_ATOMIC, safe_needed);
+	return buffer ? 0 : -ENOMEM;
+}
+
+/**
+ * alloc_highmem_pages - Allocate some highmem pages for the image.
+ *
+ * Try to allocate as many pages as needed, but if the number of free highmem
+ * pages is less than that, allocate them all.
+ */
+static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
+					       unsigned int nr_highmem)
+{
+	unsigned int to_alloc = count_free_highmem_pages();
+
+	if (to_alloc > nr_highmem)
+		to_alloc = nr_highmem;
+
+	nr_highmem -= to_alloc;
+	while (to_alloc-- > 0) {
+		struct page *page;
+
+		page = alloc_image_page(__GFP_HIGHMEM|__GFP_KSWAPD_RECLAIM);
+		memory_bm_set_bit(bm, page_to_pfn(page));
+	}
+	return nr_highmem;
+}
+#else
+static inline int get_highmem_buffer(int safe_needed) { return 0; }
+
+static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
+					       unsigned int n) { return 0; }
+#endif /* CONFIG_HIGHMEM */
+
+/**
+ * swsusp_alloc - Allocate memory for hibernation image.
+ *
+ * We first try to allocate as many highmem pages as there are
+ * saveable highmem pages in the system.  If that fails, we allocate
+ * non-highmem pages for the copies of the remaining highmem ones.
+ *
+ * In this approach it is likely that the copies of highmem pages will
+ * also be located in the high memory, because of the way in which
+ * copy_data_pages() works.
+ */
+static int swsusp_alloc(struct memory_bitmap *copy_bm,
+			unsigned int nr_pages, unsigned int nr_highmem)
+{
+	if (nr_highmem > 0) {
+		if (get_highmem_buffer(PG_ANY))
+			goto err_out;
+		if (nr_highmem > alloc_highmem) {
+			nr_highmem -= alloc_highmem;
+			nr_pages += alloc_highmem_pages(copy_bm, nr_highmem);
+		}
+	}
+	if (nr_pages > alloc_normal) {
+		nr_pages -= alloc_normal;
+		while (nr_pages-- > 0) {
+			struct page *page;
+
+			page = alloc_image_page(GFP_ATOMIC);
+			if (!page)
+				goto err_out;
+			memory_bm_set_bit(copy_bm, page_to_pfn(page));
+		}
+	}
+
+	return 0;
+
+ err_out:
+	swsusp_free();
+	return -ENOMEM;
+}
+
+asmlinkage __visible int swsusp_save(void)
+{
+	unsigned int nr_pages, nr_highmem;
+
+	pr_info("Creating image:\n");
+
+	drain_local_pages(NULL);
+	nr_pages = count_data_pages();
+	nr_highmem = count_highmem_pages();
+	pr_info("Need to copy %u pages\n", nr_pages + nr_highmem);
+
+	if (!enough_free_mem(nr_pages, nr_highmem)) {
+		pr_err("Not enough free memory\n");
+		return -ENOMEM;
+	}
+
+	if (swsusp_alloc(&copy_bm, nr_pages, nr_highmem)) {
+		pr_err("Memory allocation failed\n");
+		return -ENOMEM;
+	}
+
+	/*
+	 * During allocating of suspend pagedir, new cold pages may appear.
+	 * Kill them.
+	 */
+	drain_local_pages(NULL);
+	copy_data_pages(&copy_bm, &orig_bm);
+
+	/*
+	 * End of critical section. From now on, we can write to memory,
+	 * but we should not touch disk. This specially means we must _not_
+	 * touch swap space! Except we must write out our image of course.
+	 */
+
+	nr_pages += nr_highmem;
+	nr_copy_pages = nr_pages;
+	nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
+
+	pr_info("Image created (%d pages copied)\n", nr_pages);
+
+	return 0;
+}
+
+#ifndef CONFIG_ARCH_HIBERNATION_HEADER
+static int init_header_complete(struct swsusp_info *info)
+{
+	memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));
+	info->version_code = LINUX_VERSION_CODE;
+	return 0;
+}
+
+static const char *check_image_kernel(struct swsusp_info *info)
+{
+	if (info->version_code != LINUX_VERSION_CODE)
+		return "kernel version";
+	if (strcmp(info->uts.sysname,init_utsname()->sysname))
+		return "system type";
+	if (strcmp(info->uts.release,init_utsname()->release))
+		return "kernel release";
+	if (strcmp(info->uts.version,init_utsname()->version))
+		return "version";
+	if (strcmp(info->uts.machine,init_utsname()->machine))
+		return "machine";
+	return NULL;
+}
+#endif /* CONFIG_ARCH_HIBERNATION_HEADER */
+
+unsigned long snapshot_get_image_size(void)
+{
+	return nr_copy_pages + nr_meta_pages + 1;
+}
+
+static int init_header(struct swsusp_info *info)
+{
+	memset(info, 0, sizeof(struct swsusp_info));
+	info->num_physpages = get_num_physpages();
+	info->image_pages = nr_copy_pages;
+	info->pages = snapshot_get_image_size();
+	info->size = info->pages;
+	info->size <<= PAGE_SHIFT;
+	return init_header_complete(info);
+}
+
+/**
+ * pack_pfns - Prepare PFNs for saving.
+ * @bm: Memory bitmap.
+ * @buf: Memory buffer to store the PFNs in.
+ *
+ * PFNs corresponding to set bits in @bm are stored in the area of memory
+ * pointed to by @buf (1 page at a time).
+ */
+static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
+{
+	int j;
+
+	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
+		buf[j] = memory_bm_next_pfn(bm);
+		if (unlikely(buf[j] == BM_END_OF_MAP))
+			break;
+	}
+}
+
+/**
+ * snapshot_read_next - Get the address to read the next image page from.
+ * @handle: Snapshot handle to be used for the reading.
+ *
+ * On the first call, @handle should point to a zeroed snapshot_handle
+ * structure.  The structure gets populated then and a pointer to it should be
+ * passed to this function every next time.
+ *
+ * On success, the function returns a positive number.  Then, the caller
+ * is allowed to read up to the returned number of bytes from the memory
+ * location computed by the data_of() macro.
+ *
+ * The function returns 0 to indicate the end of the data stream condition,
+ * and negative numbers are returned on errors.  If that happens, the structure
+ * pointed to by @handle is not updated and should not be used any more.
+ */
+int snapshot_read_next(struct snapshot_handle *handle)
+{
+	if (handle->cur > nr_meta_pages + nr_copy_pages)
+		return 0;
+
+	if (!buffer) {
+		/* This makes the buffer be freed by swsusp_free() */
+		buffer = get_image_page(GFP_ATOMIC, PG_ANY);
+		if (!buffer)
+			return -ENOMEM;
+	}
+	if (!handle->cur) {
+		int error;
+
+		error = init_header((struct swsusp_info *)buffer);
+		if (error)
+			return error;
+		handle->buffer = buffer;
+		memory_bm_position_reset(&orig_bm);
+		memory_bm_position_reset(&copy_bm);
+	} else if (handle->cur <= nr_meta_pages) {
+		clear_page(buffer);
+		pack_pfns(buffer, &orig_bm);
+	} else {
+		struct page *page;
+
+		page = pfn_to_page(memory_bm_next_pfn(&copy_bm));
+		if (PageHighMem(page)) {
+			/*
+			 * Highmem pages are copied to the buffer,
+			 * because we can't return with a kmapped
+			 * highmem page (we may not be called again).
+			 */
+			void *kaddr;
+
+			kaddr = kmap_atomic(page);
+			copy_page(buffer, kaddr);
+			kunmap_atomic(kaddr);
+			handle->buffer = buffer;
+		} else {
+			handle->buffer = page_address(page);
+		}
+	}
+	handle->cur++;
+	return PAGE_SIZE;
+}
+
+static void duplicate_memory_bitmap(struct memory_bitmap *dst,
+				    struct memory_bitmap *src)
+{
+	unsigned long pfn;
+
+	memory_bm_position_reset(src);
+	pfn = memory_bm_next_pfn(src);
+	while (pfn != BM_END_OF_MAP) {
+		memory_bm_set_bit(dst, pfn);
+		pfn = memory_bm_next_pfn(src);
+	}
+}
+
+/**
+ * mark_unsafe_pages - Mark pages that were used before hibernation.
+ *
+ * Mark the pages that cannot be used for storing the image during restoration,
+ * because they conflict with the pages that had been used before hibernation.
+ */
+static void mark_unsafe_pages(struct memory_bitmap *bm)
+{
+	unsigned long pfn;
+
+	/* Clear the "free"/"unsafe" bit for all PFNs */
+	memory_bm_position_reset(free_pages_map);
+	pfn = memory_bm_next_pfn(free_pages_map);
+	while (pfn != BM_END_OF_MAP) {
+		memory_bm_clear_current(free_pages_map);
+		pfn = memory_bm_next_pfn(free_pages_map);
+	}
+
+	/* Mark pages that correspond to the "original" PFNs as "unsafe" */
+	duplicate_memory_bitmap(free_pages_map, bm);
+
+	allocated_unsafe_pages = 0;
+}
+
+static int check_header(struct swsusp_info *info)
+{
+	const char *reason;
+
+	reason = check_image_kernel(info);
+	if (!reason && info->num_physpages != get_num_physpages())
+		reason = "memory size";
+	if (reason) {
+		pr_err("Image mismatch: %s\n", reason);
+		return -EPERM;
+	}
+	return 0;
+}
+
+/**
+ * load_header - Check the image header and copy the data from it.
+ */
+static int load_header(struct swsusp_info *info)
+{
+	int error;
+
+	restore_pblist = NULL;
+	error = check_header(info);
+	if (!error) {
+		nr_copy_pages = info->image_pages;
+		nr_meta_pages = info->pages - info->image_pages - 1;
+	}
+	return error;
+}
+
+/**
+ * unpack_orig_pfns - Set bits corresponding to given PFNs in a memory bitmap.
+ * @bm: Memory bitmap.
+ * @buf: Area of memory containing the PFNs.
+ *
+ * For each element of the array pointed to by @buf (1 page at a time), set the
+ * corresponding bit in @bm.
+ */
+static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
+{
+	int j;
+
+	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
+		if (unlikely(buf[j] == BM_END_OF_MAP))
+			break;
+
+		if (pfn_valid(buf[j]) && memory_bm_pfn_present(bm, buf[j]))
+			memory_bm_set_bit(bm, buf[j]);
+		else
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_HIGHMEM
+/*
+ * struct highmem_pbe is used for creating the list of highmem pages that
+ * should be restored atomically during the resume from disk, because the page
+ * frames they have occupied before the suspend are in use.
+ */
+struct highmem_pbe {
+	struct page *copy_page;	/* data is here now */
+	struct page *orig_page;	/* data was here before the suspend */
+	struct highmem_pbe *next;
+};
+
+/*
+ * List of highmem PBEs needed for restoring the highmem pages that were
+ * allocated before the suspend and included in the suspend image, but have
+ * also been allocated by the "resume" kernel, so their contents cannot be
+ * written directly to their "original" page frames.
+ */
+static struct highmem_pbe *highmem_pblist;
+
+/**
+ * count_highmem_image_pages - Compute the number of highmem pages in the image.
+ * @bm: Memory bitmap.
+ *
+ * The bits in @bm that correspond to image pages are assumed to be set.
+ */
+static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
+{
+	unsigned long pfn;
+	unsigned int cnt = 0;
+
+	memory_bm_position_reset(bm);
+	pfn = memory_bm_next_pfn(bm);
+	while (pfn != BM_END_OF_MAP) {
+		if (PageHighMem(pfn_to_page(pfn)))
+			cnt++;
+
+		pfn = memory_bm_next_pfn(bm);
+	}
+	return cnt;
+}
+
+static unsigned int safe_highmem_pages;
+
+static struct memory_bitmap *safe_highmem_bm;
+
+/**
+ * prepare_highmem_image - Allocate memory for loading highmem data from image.
+ * @bm: Pointer to an uninitialized memory bitmap structure.
+ * @nr_highmem_p: Pointer to the number of highmem image pages.
+ *
+ * Try to allocate as many highmem pages as there are highmem image pages
+ * (@nr_highmem_p points to the variable containing the number of highmem image
+ * pages).  The pages that are "safe" (ie. will not be overwritten when the
+ * hibernation image is restored entirely) have the corresponding bits set in
+ * @bm (it must be uninitialized).
+ *
+ * NOTE: This function should not be called if there are no highmem image pages.
+ */
+static int prepare_highmem_image(struct memory_bitmap *bm,
+				 unsigned int *nr_highmem_p)
+{
+	unsigned int to_alloc;
+
+	if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
+		return -ENOMEM;
+
+	if (get_highmem_buffer(PG_SAFE))
+		return -ENOMEM;
+
+	to_alloc = count_free_highmem_pages();
+	if (to_alloc > *nr_highmem_p)
+		to_alloc = *nr_highmem_p;
+	else
+		*nr_highmem_p = to_alloc;
+
+	safe_highmem_pages = 0;
+	while (to_alloc-- > 0) {
+		struct page *page;
+
+		page = alloc_page(__GFP_HIGHMEM);
+		if (!swsusp_page_is_free(page)) {
+			/* The page is "safe", set its bit the bitmap */
+			memory_bm_set_bit(bm, page_to_pfn(page));
+			safe_highmem_pages++;
+		}
+		/* Mark the page as allocated */
+		swsusp_set_page_forbidden(page);
+		swsusp_set_page_free(page);
+	}
+	memory_bm_position_reset(bm);
+	safe_highmem_bm = bm;
+	return 0;
+}
+
+static struct page *last_highmem_page;
+
+/**
+ * get_highmem_page_buffer - Prepare a buffer to store a highmem image page.
+ *
+ * For a given highmem image page get a buffer that suspend_write_next() should
+ * return to its caller to write to.
+ *
+ * If the page is to be saved to its "original" page frame or a copy of
+ * the page is to be made in the highmem, @buffer is returned.  Otherwise,
+ * the copy of the page is to be made in normal memory, so the address of
+ * the copy is returned.
+ *
+ * If @buffer is returned, the caller of suspend_write_next() will write
+ * the page's contents to @buffer, so they will have to be copied to the
+ * right location on the next call to suspend_write_next() and it is done
+ * with the help of copy_last_highmem_page().  For this purpose, if
+ * @buffer is returned, @last_highmem_page is set to the page to which
+ * the data will have to be copied from @buffer.
+ */
+static void *get_highmem_page_buffer(struct page *page,
+				     struct chain_allocator *ca)
+{
+	struct highmem_pbe *pbe;
+	void *kaddr;
+
+	if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
+		/*
+		 * We have allocated the "original" page frame and we can
+		 * use it directly to store the loaded page.
+		 */
+		last_highmem_page = page;
+		return buffer;
+	}
+	/*
+	 * The "original" page frame has not been allocated and we have to
+	 * use a "safe" page frame to store the loaded page.
+	 */
+	pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
+	if (!pbe) {
+		swsusp_free();
+		return ERR_PTR(-ENOMEM);
+	}
+	pbe->orig_page = page;
+	if (safe_highmem_pages > 0) {
+		struct page *tmp;
+
+		/* Copy of the page will be stored in high memory */
+		kaddr = buffer;
+		tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
+		safe_highmem_pages--;
+		last_highmem_page = tmp;
+		pbe->copy_page = tmp;
+	} else {
+		/* Copy of the page will be stored in normal memory */
+		kaddr = __get_safe_page(ca->gfp_mask);
+		if (!kaddr)
+			return ERR_PTR(-ENOMEM);
+		pbe->copy_page = virt_to_page(kaddr);
+	}
+	pbe->next = highmem_pblist;
+	highmem_pblist = pbe;
+	return kaddr;
+}
+
+/**
+ * copy_last_highmem_page - Copy most the most recent highmem image page.
+ *
+ * Copy the contents of a highmem image from @buffer, where the caller of
+ * snapshot_write_next() has stored them, to the right location represented by
+ * @last_highmem_page .
+ */
+static void copy_last_highmem_page(void)
+{
+	if (last_highmem_page) {
+		void *dst;
+
+		dst = kmap_atomic(last_highmem_page);
+		copy_page(dst, buffer);
+		kunmap_atomic(dst);
+		last_highmem_page = NULL;
+	}
+}
+
+static inline int last_highmem_page_copied(void)
+{
+	return !last_highmem_page;
+}
+
+static inline void free_highmem_data(void)
+{
+	if (safe_highmem_bm)
+		memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);
+
+	if (buffer)
+		free_image_page(buffer, PG_UNSAFE_CLEAR);
+}
+#else
+static unsigned int count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }
+
+static inline int prepare_highmem_image(struct memory_bitmap *bm,
+					unsigned int *nr_highmem_p) { return 0; }
+
+static inline void *get_highmem_page_buffer(struct page *page,
+					    struct chain_allocator *ca)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline void copy_last_highmem_page(void) {}
+static inline int last_highmem_page_copied(void) { return 1; }
+static inline void free_highmem_data(void) {}
+#endif /* CONFIG_HIGHMEM */
+
+#define PBES_PER_LINKED_PAGE	(LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
+
+/**
+ * prepare_image - Make room for loading hibernation image.
+ * @new_bm: Uninitialized memory bitmap structure.
+ * @bm: Memory bitmap with unsafe pages marked.
+ *
+ * Use @bm to mark the pages that will be overwritten in the process of
+ * restoring the system memory state from the suspend image ("unsafe" pages)
+ * and allocate memory for the image.
+ *
+ * The idea is to allocate a new memory bitmap first and then allocate
+ * as many pages as needed for image data, but without specifying what those
+ * pages will be used for just yet.  Instead, we mark them all as allocated and
+ * create a lists of "safe" pages to be used later.  On systems with high
+ * memory a list of "safe" highmem pages is created too.
+ */
+static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
+{
+	unsigned int nr_pages, nr_highmem;
+	struct linked_page *lp;
+	int error;
+
+	/* If there is no highmem, the buffer will not be necessary */
+	free_image_page(buffer, PG_UNSAFE_CLEAR);
+	buffer = NULL;
+
+	nr_highmem = count_highmem_image_pages(bm);
+	mark_unsafe_pages(bm);
+
+	error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE);
+	if (error)
+		goto Free;
+
+	duplicate_memory_bitmap(new_bm, bm);
+	memory_bm_free(bm, PG_UNSAFE_KEEP);
+	if (nr_highmem > 0) {
+		error = prepare_highmem_image(bm, &nr_highmem);
+		if (error)
+			goto Free;
+	}
+	/*
+	 * Reserve some safe pages for potential later use.
+	 *
+	 * NOTE: This way we make sure there will be enough safe pages for the
+	 * chain_alloc() in get_buffer().  It is a bit wasteful, but
+	 * nr_copy_pages cannot be greater than 50% of the memory anyway.
+	 *
+	 * nr_copy_pages cannot be less than allocated_unsafe_pages too.
+	 */
+	nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
+	nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
+	while (nr_pages > 0) {
+		lp = get_image_page(GFP_ATOMIC, PG_SAFE);
+		if (!lp) {
+			error = -ENOMEM;
+			goto Free;
+		}
+		lp->next = safe_pages_list;
+		safe_pages_list = lp;
+		nr_pages--;
+	}
+	/* Preallocate memory for the image */
+	nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
+	while (nr_pages > 0) {
+		lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
+		if (!lp) {
+			error = -ENOMEM;
+			goto Free;
+		}
+		if (!swsusp_page_is_free(virt_to_page(lp))) {
+			/* The page is "safe", add it to the list */
+			lp->next = safe_pages_list;
+			safe_pages_list = lp;
+		}
+		/* Mark the page as allocated */
+		swsusp_set_page_forbidden(virt_to_page(lp));
+		swsusp_set_page_free(virt_to_page(lp));
+		nr_pages--;
+	}
+	return 0;
+
+ Free:
+	swsusp_free();
+	return error;
+}
+
+/**
+ * get_buffer - Get the address to store the next image data page.
+ *
+ * Get the address that snapshot_write_next() should return to its caller to
+ * write to.
+ */
+static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
+{
+	struct pbe *pbe;
+	struct page *page;
+	unsigned long pfn = memory_bm_next_pfn(bm);
+
+	if (pfn == BM_END_OF_MAP)
+		return ERR_PTR(-EFAULT);
+
+	page = pfn_to_page(pfn);
+	if (PageHighMem(page))
+		return get_highmem_page_buffer(page, ca);
+
+	if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
+		/*
+		 * We have allocated the "original" page frame and we can
+		 * use it directly to store the loaded page.
+		 */
+		return page_address(page);
+
+	/*
+	 * The "original" page frame has not been allocated and we have to
+	 * use a "safe" page frame to store the loaded page.
+	 */
+	pbe = chain_alloc(ca, sizeof(struct pbe));
+	if (!pbe) {
+		swsusp_free();
+		return ERR_PTR(-ENOMEM);
+	}
+	pbe->orig_address = page_address(page);
+	pbe->address = __get_safe_page(ca->gfp_mask);
+	if (!pbe->address)
+		return ERR_PTR(-ENOMEM);
+	pbe->next = restore_pblist;
+	restore_pblist = pbe;
+	return pbe->address;
+}
+
+/**
+ * snapshot_write_next - Get the address to store the next image page.
+ * @handle: Snapshot handle structure to guide the writing.
+ *
+ * On the first call, @handle should point to a zeroed snapshot_handle
+ * structure.  The structure gets populated then and a pointer to it should be
+ * passed to this function every next time.
+ *
+ * On success, the function returns a positive number.  Then, the caller
+ * is allowed to write up to the returned number of bytes to the memory
+ * location computed by the data_of() macro.
+ *
+ * The function returns 0 to indicate the "end of file" condition.  Negative
+ * numbers are returned on errors, in which cases the structure pointed to by
+ * @handle is not updated and should not be used any more.
+ */
+int snapshot_write_next(struct snapshot_handle *handle)
+{
+	static struct chain_allocator ca;
+	int error = 0;
+
+	/* Check if we have already loaded the entire image */
+	if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages)
+		return 0;
+
+	if (!handle->cur) {
+		if (!buffer)
+			/* This makes the buffer be freed by swsusp_free() */
+			buffer = get_image_page(GFP_ATOMIC, PG_ANY);
+
+		if (!buffer)
+			return -ENOMEM;
+
+		handle->buffer = buffer;
+	} else if (handle->cur == 1) {
+		error = load_header(buffer);
+		if (error)
+			return error;
+
+		safe_pages_list = NULL;
+
+		error = memory_bm_create(&copy_bm, GFP_ATOMIC, PG_ANY);
+		if (error)
+			return error;
+
+		hibernate_restore_protection_begin();
+	} else if (handle->cur <= nr_meta_pages + 1) {
+		error = unpack_orig_pfns(buffer, &copy_bm);
+		if (error)
+			return error;
+
+		if (handle->cur == nr_meta_pages + 1) {
+			error = prepare_image(&orig_bm, &copy_bm);
+			if (error)
+				return error;
+
+			chain_init(&ca, GFP_ATOMIC, PG_SAFE);
+			memory_bm_position_reset(&orig_bm);
+			restore_pblist = NULL;
+			handle->buffer = get_buffer(&orig_bm, &ca);
+			if (IS_ERR(handle->buffer))
+				return PTR_ERR(handle->buffer);
+		}
+	} else {
+		copy_last_highmem_page();
+		hibernate_restore_protect_page(handle->buffer);
+		handle->buffer = get_buffer(&orig_bm, &ca);
+		if (IS_ERR(handle->buffer))
+			return PTR_ERR(handle->buffer);
+	}
+	handle->sync_read = (handle->buffer == buffer);
+	handle->cur++;
+	return PAGE_SIZE;
+}
+
+/**
+ * snapshot_write_finalize - Complete the loading of a hibernation image.
+ *
+ * Must be called after the last call to snapshot_write_next() in case the last
+ * page in the image happens to be a highmem page and its contents should be
+ * stored in highmem.  Additionally, it recycles bitmap memory that's not
+ * necessary any more.
+ */
+void snapshot_write_finalize(struct snapshot_handle *handle)
+{
+	copy_last_highmem_page();
+	hibernate_restore_protect_page(handle->buffer);
+	/* Do that only if we have loaded the image entirely */
+	if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) {
+		memory_bm_recycle(&orig_bm);
+		free_highmem_data();
+	}
+}
+
+int snapshot_image_loaded(struct snapshot_handle *handle)
+{
+	return !(!nr_copy_pages || !last_highmem_page_copied() ||
+			handle->cur <= nr_meta_pages + nr_copy_pages);
+}
+
+#ifdef CONFIG_HIGHMEM
+/* Assumes that @buf is ready and points to a "safe" page */
+static inline void swap_two_pages_data(struct page *p1, struct page *p2,
+				       void *buf)
+{
+	void *kaddr1, *kaddr2;
+
+	kaddr1 = kmap_atomic(p1);
+	kaddr2 = kmap_atomic(p2);
+	copy_page(buf, kaddr1);
+	copy_page(kaddr1, kaddr2);
+	copy_page(kaddr2, buf);
+	kunmap_atomic(kaddr2);
+	kunmap_atomic(kaddr1);
+}
+
+/**
+ * restore_highmem - Put highmem image pages into their original locations.
+ *
+ * For each highmem page that was in use before hibernation and is included in
+ * the image, and also has been allocated by the "restore" kernel, swap its
+ * current contents with the previous (ie. "before hibernation") ones.
+ *
+ * If the restore eventually fails, we can call this function once again and
+ * restore the highmem state as seen by the restore kernel.
+ */
+int restore_highmem(void)
+{
+	struct highmem_pbe *pbe = highmem_pblist;
+	void *buf;
+
+	if (!pbe)
+		return 0;
+
+	buf = get_image_page(GFP_ATOMIC, PG_SAFE);
+	if (!buf)
+		return -ENOMEM;
+
+	while (pbe) {
+		swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
+		pbe = pbe->next;
+	}
+	free_image_page(buf, PG_UNSAFE_CLEAR);
+	return 0;
+}
+#endif /* CONFIG_HIGHMEM */
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
new file mode 100644
index 000000000..fa3bf161d
--- /dev/null
+++ b/kernel/power/suspend.c
@@ -0,0 +1,629 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/power/suspend.c - Suspend to RAM and standby functionality.
+ *
+ * Copyright (c) 2003 Patrick Mochel
+ * Copyright (c) 2003 Open Source Development Lab
+ * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
+ */
+
+#define pr_fmt(fmt) "PM: " fmt
+
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/cpu.h>
+#include <linux/cpuidle.h>
+#include <linux/gfp.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/suspend.h>
+#include <linux/syscore_ops.h>
+#include <linux/swait.h>
+#include <linux/ftrace.h>
+#include <trace/events/power.h>
+#include <linux/compiler.h>
+#include <linux/moduleparam.h>
+
+#include "power.h"
+
+const char * const pm_labels[] = {
+	[PM_SUSPEND_TO_IDLE] = "freeze",
+	[PM_SUSPEND_STANDBY] = "standby",
+	[PM_SUSPEND_MEM] = "mem",
+};
+const char *pm_states[PM_SUSPEND_MAX];
+static const char * const mem_sleep_labels[] = {
+	[PM_SUSPEND_TO_IDLE] = "s2idle",
+	[PM_SUSPEND_STANDBY] = "shallow",
+	[PM_SUSPEND_MEM] = "deep",
+};
+const char *mem_sleep_states[PM_SUSPEND_MAX];
+
+suspend_state_t mem_sleep_current = PM_SUSPEND_TO_IDLE;
+suspend_state_t mem_sleep_default = PM_SUSPEND_MAX;
+suspend_state_t pm_suspend_target_state;
+EXPORT_SYMBOL_GPL(pm_suspend_target_state);
+
+unsigned int pm_suspend_global_flags;
+EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
+
+static const struct platform_suspend_ops *suspend_ops;
+static const struct platform_s2idle_ops *s2idle_ops;
+static DECLARE_SWAIT_QUEUE_HEAD(s2idle_wait_head);
+
+enum s2idle_states __read_mostly s2idle_state;
+static DEFINE_RAW_SPINLOCK(s2idle_lock);
+
+/**
+ * pm_suspend_default_s2idle - Check if suspend-to-idle is the default suspend.
+ *
+ * Return 'true' if suspend-to-idle has been selected as the default system
+ * suspend method.
+ */
+bool pm_suspend_default_s2idle(void)
+{
+	return mem_sleep_current == PM_SUSPEND_TO_IDLE;
+}
+EXPORT_SYMBOL_GPL(pm_suspend_default_s2idle);
+
+void s2idle_set_ops(const struct platform_s2idle_ops *ops)
+{
+	unsigned int sleep_flags;
+
+	sleep_flags = lock_system_sleep();
+	s2idle_ops = ops;
+	unlock_system_sleep(sleep_flags);
+}
+
+static void s2idle_begin(void)
+{
+	s2idle_state = S2IDLE_STATE_NONE;
+}
+
+static void s2idle_enter(void)
+{
+	trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true);
+
+	raw_spin_lock_irq(&s2idle_lock);
+	if (pm_wakeup_pending())
+		goto out;
+
+	s2idle_state = S2IDLE_STATE_ENTER;
+	raw_spin_unlock_irq(&s2idle_lock);
+
+	cpus_read_lock();
+
+	/* Push all the CPUs into the idle loop. */
+	wake_up_all_idle_cpus();
+	/* Make the current CPU wait so it can enter the idle loop too. */
+	swait_event_exclusive(s2idle_wait_head,
+		    s2idle_state == S2IDLE_STATE_WAKE);
+
+	cpus_read_unlock();
+
+	raw_spin_lock_irq(&s2idle_lock);
+
+ out:
+	s2idle_state = S2IDLE_STATE_NONE;
+	raw_spin_unlock_irq(&s2idle_lock);
+
+	trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
+}
+
+static void s2idle_loop(void)
+{
+	pm_pr_dbg("suspend-to-idle\n");
+
+	/*
+	 * Suspend-to-idle equals:
+	 * frozen processes + suspended devices + idle processors.
+	 * Thus s2idle_enter() should be called right after all devices have
+	 * been suspended.
+	 *
+	 * Wakeups during the noirq suspend of devices may be spurious, so try
+	 * to avoid them upfront.
+	 */
+	for (;;) {
+		if (s2idle_ops && s2idle_ops->wake) {
+			if (s2idle_ops->wake())
+				break;
+		} else if (pm_wakeup_pending()) {
+			break;
+		}
+
+		if (s2idle_ops && s2idle_ops->check)
+			s2idle_ops->check();
+
+		s2idle_enter();
+	}
+
+	pm_pr_dbg("resume from suspend-to-idle\n");
+}
+
+void s2idle_wake(void)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&s2idle_lock, flags);
+	if (s2idle_state > S2IDLE_STATE_NONE) {
+		s2idle_state = S2IDLE_STATE_WAKE;
+		swake_up_one(&s2idle_wait_head);
+	}
+	raw_spin_unlock_irqrestore(&s2idle_lock, flags);
+}
+EXPORT_SYMBOL_GPL(s2idle_wake);
+
+static bool valid_state(suspend_state_t state)
+{
+	/*
+	 * The PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states require low-level
+	 * support and need to be valid to the low-level implementation.
+	 *
+	 * No ->valid() or ->enter() callback implies that none are valid.
+	 */
+	return suspend_ops && suspend_ops->valid && suspend_ops->valid(state) &&
+		suspend_ops->enter;
+}
+
+void __init pm_states_init(void)
+{
+	/* "mem" and "freeze" are always present in /sys/power/state. */
+	pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
+	pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
+	/*
+	 * Suspend-to-idle should be supported even without any suspend_ops,
+	 * initialize mem_sleep_states[] accordingly here.
+	 */
+	mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
+}
+
+static int __init mem_sleep_default_setup(char *str)
+{
+	suspend_state_t state;
+
+	for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
+		if (mem_sleep_labels[state] &&
+		    !strcmp(str, mem_sleep_labels[state])) {
+			mem_sleep_default = state;
+			break;
+		}
+
+	return 1;
+}
+__setup("mem_sleep_default=", mem_sleep_default_setup);
+
+/**
+ * suspend_set_ops - Set the global suspend method table.
+ * @ops: Suspend operations to use.
+ */
+void suspend_set_ops(const struct platform_suspend_ops *ops)
+{
+	unsigned int sleep_flags;
+
+	sleep_flags = lock_system_sleep();
+
+	suspend_ops = ops;
+
+	if (valid_state(PM_SUSPEND_STANDBY)) {
+		mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
+		pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
+		if (mem_sleep_default == PM_SUSPEND_STANDBY)
+			mem_sleep_current = PM_SUSPEND_STANDBY;
+	}
+	if (valid_state(PM_SUSPEND_MEM)) {
+		mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
+		if (mem_sleep_default >= PM_SUSPEND_MEM)
+			mem_sleep_current = PM_SUSPEND_MEM;
+	}
+
+	unlock_system_sleep(sleep_flags);
+}
+EXPORT_SYMBOL_GPL(suspend_set_ops);
+
+/**
+ * suspend_valid_only_mem - Generic memory-only valid callback.
+ * @state: Target system sleep state.
+ *
+ * Platform drivers that implement mem suspend only and only need to check for
+ * that in their .valid() callback can use this instead of rolling their own
+ * .valid() callback.
+ */
+int suspend_valid_only_mem(suspend_state_t state)
+{
+	return state == PM_SUSPEND_MEM;
+}
+EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
+
+static bool sleep_state_supported(suspend_state_t state)
+{
+	return state == PM_SUSPEND_TO_IDLE ||
+	       (valid_state(state) && !cxl_mem_active());
+}
+
+static int platform_suspend_prepare(suspend_state_t state)
+{
+	return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
+		suspend_ops->prepare() : 0;
+}
+
+static int platform_suspend_prepare_late(suspend_state_t state)
+{
+	return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
+		s2idle_ops->prepare() : 0;
+}
+
+static int platform_suspend_prepare_noirq(suspend_state_t state)
+{
+	if (state == PM_SUSPEND_TO_IDLE)
+		return s2idle_ops && s2idle_ops->prepare_late ?
+			s2idle_ops->prepare_late() : 0;
+
+	return suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0;
+}
+
+static void platform_resume_noirq(suspend_state_t state)
+{
+	if (state == PM_SUSPEND_TO_IDLE) {
+		if (s2idle_ops && s2idle_ops->restore_early)
+			s2idle_ops->restore_early();
+	} else if (suspend_ops->wake) {
+		suspend_ops->wake();
+	}
+}
+
+static void platform_resume_early(suspend_state_t state)
+{
+	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
+		s2idle_ops->restore();
+}
+
+static void platform_resume_finish(suspend_state_t state)
+{
+	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
+		suspend_ops->finish();
+}
+
+static int platform_suspend_begin(suspend_state_t state)
+{
+	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
+		return s2idle_ops->begin();
+	else if (suspend_ops && suspend_ops->begin)
+		return suspend_ops->begin(state);
+	else
+		return 0;
+}
+
+static void platform_resume_end(suspend_state_t state)
+{
+	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
+		s2idle_ops->end();
+	else if (suspend_ops && suspend_ops->end)
+		suspend_ops->end();
+}
+
+static void platform_recover(suspend_state_t state)
+{
+	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
+		suspend_ops->recover();
+}
+
+static bool platform_suspend_again(suspend_state_t state)
+{
+	return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
+		suspend_ops->suspend_again() : false;
+}
+
+#ifdef CONFIG_PM_DEBUG
+static unsigned int pm_test_delay = 5;
+module_param(pm_test_delay, uint, 0644);
+MODULE_PARM_DESC(pm_test_delay,
+		 "Number of seconds to wait before resuming from suspend test");
+#endif
+
+static int suspend_test(int level)
+{
+#ifdef CONFIG_PM_DEBUG
+	if (pm_test_level == level) {
+		pr_info("suspend debug: Waiting for %d second(s).\n",
+				pm_test_delay);
+		mdelay(pm_test_delay * 1000);
+		return 1;
+	}
+#endif /* !CONFIG_PM_DEBUG */
+	return 0;
+}
+
+/**
+ * suspend_prepare - Prepare for entering system sleep state.
+ * @state: Target system sleep state.
+ *
+ * Common code run for every system sleep state that can be entered (except for
+ * hibernation).  Run suspend notifiers, allocate the "suspend" console and
+ * freeze processes.
+ */
+static int suspend_prepare(suspend_state_t state)
+{
+	int error;
+
+	if (!sleep_state_supported(state))
+		return -EPERM;
+
+	pm_prepare_console();
+
+	error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND);
+	if (error)
+		goto Restore;
+
+	trace_suspend_resume(TPS("freeze_processes"), 0, true);
+	error = suspend_freeze_processes();
+	trace_suspend_resume(TPS("freeze_processes"), 0, false);
+	if (!error)
+		return 0;
+
+	suspend_stats.failed_freeze++;
+	dpm_save_failed_step(SUSPEND_FREEZE);
+	pm_notifier_call_chain(PM_POST_SUSPEND);
+ Restore:
+	pm_restore_console();
+	return error;
+}
+
+/* default implementation */
+void __weak arch_suspend_disable_irqs(void)
+{
+	local_irq_disable();
+}
+
+/* default implementation */
+void __weak arch_suspend_enable_irqs(void)
+{
+	local_irq_enable();
+}
+
+/**
+ * suspend_enter - Make the system enter the given sleep state.
+ * @state: System sleep state to enter.
+ * @wakeup: Returns information that the sleep state should not be re-entered.
+ *
+ * This function should be called after devices have been suspended.
+ */
+static int suspend_enter(suspend_state_t state, bool *wakeup)
+{
+	int error;
+
+	error = platform_suspend_prepare(state);
+	if (error)
+		goto Platform_finish;
+
+	error = dpm_suspend_late(PMSG_SUSPEND);
+	if (error) {
+		pr_err("late suspend of devices failed\n");
+		goto Platform_finish;
+	}
+	error = platform_suspend_prepare_late(state);
+	if (error)
+		goto Devices_early_resume;
+
+	error = dpm_suspend_noirq(PMSG_SUSPEND);
+	if (error) {
+		pr_err("noirq suspend of devices failed\n");
+		goto Platform_early_resume;
+	}
+	error = platform_suspend_prepare_noirq(state);
+	if (error)
+		goto Platform_wake;
+
+	if (suspend_test(TEST_PLATFORM))
+		goto Platform_wake;
+
+	if (state == PM_SUSPEND_TO_IDLE) {
+		s2idle_loop();
+		goto Platform_wake;
+	}
+
+	error = pm_sleep_disable_secondary_cpus();
+	if (error || suspend_test(TEST_CPUS))
+		goto Enable_cpus;
+
+	arch_suspend_disable_irqs();
+	BUG_ON(!irqs_disabled());
+
+	system_state = SYSTEM_SUSPEND;
+
+	error = syscore_suspend();
+	if (!error) {
+		*wakeup = pm_wakeup_pending();
+		if (!(suspend_test(TEST_CORE) || *wakeup)) {
+			trace_suspend_resume(TPS("machine_suspend"),
+				state, true);
+			error = suspend_ops->enter(state);
+			trace_suspend_resume(TPS("machine_suspend"),
+				state, false);
+		} else if (*wakeup) {
+			error = -EBUSY;
+		}
+		syscore_resume();
+	}
+
+	system_state = SYSTEM_RUNNING;
+
+	arch_suspend_enable_irqs();
+	BUG_ON(irqs_disabled());
+
+ Enable_cpus:
+	pm_sleep_enable_secondary_cpus();
+
+ Platform_wake:
+	platform_resume_noirq(state);
+	dpm_resume_noirq(PMSG_RESUME);
+
+ Platform_early_resume:
+	platform_resume_early(state);
+
+ Devices_early_resume:
+	dpm_resume_early(PMSG_RESUME);
+
+ Platform_finish:
+	platform_resume_finish(state);
+	return error;
+}
+
+/**
+ * suspend_devices_and_enter - Suspend devices and enter system sleep state.
+ * @state: System sleep state to enter.
+ */
+int suspend_devices_and_enter(suspend_state_t state)
+{
+	int error;
+	bool wakeup = false;
+
+	if (!sleep_state_supported(state))
+		return -ENOSYS;
+
+	pm_suspend_target_state = state;
+
+	if (state == PM_SUSPEND_TO_IDLE)
+		pm_set_suspend_no_platform();
+
+	error = platform_suspend_begin(state);
+	if (error)
+		goto Close;
+
+	suspend_console();
+	suspend_test_start();
+	error = dpm_suspend_start(PMSG_SUSPEND);
+	if (error) {
+		pr_err("Some devices failed to suspend, or early wake event detected\n");
+		goto Recover_platform;
+	}
+	suspend_test_finish("suspend devices");
+	if (suspend_test(TEST_DEVICES))
+		goto Recover_platform;
+
+	do {
+		error = suspend_enter(state, &wakeup);
+	} while (!error && !wakeup && platform_suspend_again(state));
+
+ Resume_devices:
+	suspend_test_start();
+	dpm_resume_end(PMSG_RESUME);
+	suspend_test_finish("resume devices");
+	trace_suspend_resume(TPS("resume_console"), state, true);
+	resume_console();
+	trace_suspend_resume(TPS("resume_console"), state, false);
+
+ Close:
+	platform_resume_end(state);
+	pm_suspend_target_state = PM_SUSPEND_ON;
+	return error;
+
+ Recover_platform:
+	platform_recover(state);
+	goto Resume_devices;
+}
+
+/**
+ * suspend_finish - Clean up before finishing the suspend sequence.
+ *
+ * Call platform code to clean up, restart processes, and free the console that
+ * we've allocated. This routine is not called for hibernation.
+ */
+static void suspend_finish(void)
+{
+	suspend_thaw_processes();
+	pm_notifier_call_chain(PM_POST_SUSPEND);
+	pm_restore_console();
+}
+
+/**
+ * enter_state - Do common work needed to enter system sleep state.
+ * @state: System sleep state to enter.
+ *
+ * Make sure that no one else is trying to put the system into a sleep state.
+ * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
+ * system enter the given sleep state and clean up after wakeup.
+ */
+static int enter_state(suspend_state_t state)
+{
+	int error;
+
+	trace_suspend_resume(TPS("suspend_enter"), state, true);
+	if (state == PM_SUSPEND_TO_IDLE) {
+#ifdef CONFIG_PM_DEBUG
+		if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
+			pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
+			return -EAGAIN;
+		}
+#endif
+	} else if (!valid_state(state)) {
+		return -EINVAL;
+	}
+	if (!mutex_trylock(&system_transition_mutex))
+		return -EBUSY;
+
+	if (state == PM_SUSPEND_TO_IDLE)
+		s2idle_begin();
+
+	if (sync_on_suspend_enabled) {
+		trace_suspend_resume(TPS("sync_filesystems"), 0, true);
+		ksys_sync_helper();
+		trace_suspend_resume(TPS("sync_filesystems"), 0, false);
+	}
+
+	pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
+	pm_suspend_clear_flags();
+	error = suspend_prepare(state);
+	if (error)
+		goto Unlock;
+
+	if (suspend_test(TEST_FREEZER))
+		goto Finish;
+
+	trace_suspend_resume(TPS("suspend_enter"), state, false);
+	pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
+	pm_restrict_gfp_mask();
+	error = suspend_devices_and_enter(state);
+	pm_restore_gfp_mask();
+
+ Finish:
+	events_check_enabled = false;
+	pm_pr_dbg("Finishing wakeup.\n");
+	suspend_finish();
+ Unlock:
+	mutex_unlock(&system_transition_mutex);
+	return error;
+}
+
+/**
+ * pm_suspend - Externally visible function for suspending the system.
+ * @state: System sleep state to enter.
+ *
+ * Check if the value of @state represents one of the supported states,
+ * execute enter_state() and update system suspend statistics.
+ */
+int pm_suspend(suspend_state_t state)
+{
+	int error;
+
+	if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
+		return -EINVAL;
+
+	pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
+	error = enter_state(state);
+	if (error) {
+		suspend_stats.fail++;
+		dpm_save_failed_errno(error);
+	} else {
+		suspend_stats.success++;
+	}
+	pr_info("suspend exit\n");
+	return error;
+}
+EXPORT_SYMBOL(pm_suspend);
diff --git a/kernel/power/suspend_test.c b/kernel/power/suspend_test.c
new file mode 100644
index 000000000..b663a97f5
--- /dev/null
+++ b/kernel/power/suspend_test.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/power/suspend_test.c - Suspend to RAM and standby test facility.
+ *
+ * Copyright (c) 2009 Pavel Machek <pavel@ucw.cz>
+ */
+
+#include <linux/init.h>
+#include <linux/rtc.h>
+
+#include "power.h"
+
+/*
+ * We test the system suspend code by setting an RTC wakealarm a short
+ * time in the future, then suspending.  Suspending the devices won't
+ * normally take long ... some systems only need a few milliseconds.
+ *
+ * The time it takes is system-specific though, so when we test this
+ * during system bootup we allow a LOT of time.
+ */
+#define TEST_SUSPEND_SECONDS	10
+
+static unsigned long suspend_test_start_time;
+static u32 test_repeat_count_max = 1;
+static u32 test_repeat_count_current;
+
+void suspend_test_start(void)
+{
+	/* FIXME Use better timebase than "jiffies", ideally a clocksource.
+	 * What we want is a hardware counter that will work correctly even
+	 * during the irqs-are-off stages of the suspend/resume cycle...
+	 */
+	suspend_test_start_time = jiffies;
+}
+
+void suspend_test_finish(const char *label)
+{
+	long nj = jiffies - suspend_test_start_time;
+	unsigned msec;
+
+	msec = jiffies_to_msecs(abs(nj));
+	pr_info("PM: %s took %d.%03d seconds\n", label,
+			msec / 1000, msec % 1000);
+
+	/* Warning on suspend means the RTC alarm period needs to be
+	 * larger -- the system was sooo slooowwww to suspend that the
+	 * alarm (should have) fired before the system went to sleep!
+	 *
+	 * Warning on either suspend or resume also means the system
+	 * has some performance issues.  The stack dump of a WARN_ON
+	 * is more likely to get the right attention than a printk...
+	 */
+	WARN(msec > (TEST_SUSPEND_SECONDS * 1000),
+	     "Component: %s, time: %u\n", label, msec);
+}
+
+/*
+ * To test system suspend, we need a hands-off mechanism to resume the
+ * system.  RTCs wake alarms are a common self-contained mechanism.
+ */
+
+static void __init test_wakealarm(struct rtc_device *rtc, suspend_state_t state)
+{
+	static char err_readtime[] __initdata =
+		KERN_ERR "PM: can't read %s time, err %d\n";
+	static char err_wakealarm [] __initdata =
+		KERN_ERR "PM: can't set %s wakealarm, err %d\n";
+	static char err_suspend[] __initdata =
+		KERN_ERR "PM: suspend test failed, error %d\n";
+	static char info_test[] __initdata =
+		KERN_INFO "PM: test RTC wakeup from '%s' suspend\n";
+
+	time64_t		now;
+	struct rtc_wkalrm	alm;
+	int			status;
+
+	/* this may fail if the RTC hasn't been initialized */
+repeat:
+	status = rtc_read_time(rtc, &alm.time);
+	if (status < 0) {
+		printk(err_readtime, dev_name(&rtc->dev), status);
+		return;
+	}
+	now = rtc_tm_to_time64(&alm.time);
+
+	memset(&alm, 0, sizeof alm);
+	rtc_time64_to_tm(now + TEST_SUSPEND_SECONDS, &alm.time);
+	alm.enabled = true;
+
+	status = rtc_set_alarm(rtc, &alm);
+	if (status < 0) {
+		printk(err_wakealarm, dev_name(&rtc->dev), status);
+		return;
+	}
+
+	if (state == PM_SUSPEND_MEM) {
+		printk(info_test, pm_states[state]);
+		status = pm_suspend(state);
+		if (status == -ENODEV)
+			state = PM_SUSPEND_STANDBY;
+	}
+	if (state == PM_SUSPEND_STANDBY) {
+		printk(info_test, pm_states[state]);
+		status = pm_suspend(state);
+		if (status < 0)
+			state = PM_SUSPEND_TO_IDLE;
+	}
+	if (state == PM_SUSPEND_TO_IDLE) {
+		printk(info_test, pm_states[state]);
+		status = pm_suspend(state);
+	}
+
+	if (status < 0)
+		printk(err_suspend, status);
+
+	test_repeat_count_current++;
+	if (test_repeat_count_current < test_repeat_count_max)
+		goto repeat;
+
+	/* Some platforms can't detect that the alarm triggered the
+	 * wakeup, or (accordingly) disable it after it afterwards.
+	 * It's supposed to give oneshot behavior; cope.
+	 */
+	alm.enabled = false;
+	rtc_set_alarm(rtc, &alm);
+}
+
+static int __init has_wakealarm(struct device *dev, const void *data)
+{
+	struct rtc_device *candidate = to_rtc_device(dev);
+
+	if (!test_bit(RTC_FEATURE_ALARM, candidate->features))
+		return 0;
+	if (!device_may_wakeup(candidate->dev.parent))
+		return 0;
+
+	return 1;
+}
+
+/*
+ * Kernel options like "test_suspend=mem" force suspend/resume sanity tests
+ * at startup time.  They're normally disabled, for faster boot and because
+ * we can't know which states really work on this particular system.
+ */
+static const char *test_state_label __initdata;
+
+static char warn_bad_state[] __initdata =
+	KERN_WARNING "PM: can't test '%s' suspend state\n";
+
+static int __init setup_test_suspend(char *value)
+{
+	int i;
+	char *repeat;
+	char *suspend_type;
+
+	/* example : "=mem[,N]" ==> "mem[,N]" */
+	value++;
+	suspend_type = strsep(&value, ",");
+	if (!suspend_type)
+		return 1;
+
+	repeat = strsep(&value, ",");
+	if (repeat) {
+		if (kstrtou32(repeat, 0, &test_repeat_count_max))
+			return 1;
+	}
+
+	for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
+		if (!strcmp(pm_labels[i], suspend_type)) {
+			test_state_label = pm_labels[i];
+			return 1;
+		}
+
+	printk(warn_bad_state, suspend_type);
+	return 1;
+}
+__setup("test_suspend", setup_test_suspend);
+
+static int __init test_suspend(void)
+{
+	static char		warn_no_rtc[] __initdata =
+		KERN_WARNING "PM: no wakealarm-capable RTC driver is ready\n";
+
+	struct rtc_device	*rtc = NULL;
+	struct device		*dev;
+	suspend_state_t test_state;
+
+	/* PM is initialized by now; is that state testable? */
+	if (!test_state_label)
+		return 0;
+
+	for (test_state = PM_SUSPEND_MIN; test_state < PM_SUSPEND_MAX; test_state++) {
+		const char *state_label = pm_states[test_state];
+
+		if (state_label && !strcmp(test_state_label, state_label))
+			break;
+	}
+	if (test_state == PM_SUSPEND_MAX) {
+		printk(warn_bad_state, test_state_label);
+		return 0;
+	}
+
+	/* RTCs have initialized by now too ... can we use one? */
+	dev = class_find_device(rtc_class, NULL, NULL, has_wakealarm);
+	if (dev) {
+		rtc = rtc_class_open(dev_name(dev));
+		put_device(dev);
+	}
+	if (!rtc) {
+		printk(warn_no_rtc);
+		return 0;
+	}
+
+	/* go for it */
+	test_wakealarm(rtc, test_state);
+	rtc_class_close(rtc);
+	return 0;
+}
+late_initcall(test_suspend);
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
new file mode 100644
index 000000000..5ab54ab5a
--- /dev/null
+++ b/kernel/power/swap.c
@@ -0,0 +1,1619 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/kernel/power/swap.c
+ *
+ * This file provides functions for reading the suspend image from
+ * and writing it to a swap partition.
+ *
+ * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
+ * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
+ * Copyright (C) 2010-2012 Bojan Smojver <bojan@rexursive.com>
+ */
+
+#define pr_fmt(fmt) "PM: " fmt
+
+#include <linux/module.h>
+#include <linux/file.h>
+#include <linux/delay.h>
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/lzo.h>
+#include <linux/vmalloc.h>
+#include <linux/cpumask.h>
+#include <linux/atomic.h>
+#include <linux/kthread.h>
+#include <linux/crc32.h>
+#include <linux/ktime.h>
+
+#include "power.h"
+
+#define HIBERNATE_SIG	"S1SUSPEND"
+
+u32 swsusp_hardware_signature;
+
+/*
+ * When reading an {un,}compressed image, we may restore pages in place,
+ * in which case some architectures need these pages cleaning before they
+ * can be executed. We don't know which pages these may be, so clean the lot.
+ */
+static bool clean_pages_on_read;
+static bool clean_pages_on_decompress;
+
+/*
+ *	The swap map is a data structure used for keeping track of each page
+ *	written to a swap partition.  It consists of many swap_map_page
+ *	structures that contain each an array of MAP_PAGE_ENTRIES swap entries.
+ *	These structures are stored on the swap and linked together with the
+ *	help of the .next_swap member.
+ *
+ *	The swap map is created during suspend.  The swap map pages are
+ *	allocated and populated one at a time, so we only need one memory
+ *	page to set up the entire structure.
+ *
+ *	During resume we pick up all swap_map_page structures into a list.
+ */
+
+#define MAP_PAGE_ENTRIES	(PAGE_SIZE / sizeof(sector_t) - 1)
+
+/*
+ * Number of free pages that are not high.
+ */
+static inline unsigned long low_free_pages(void)
+{
+	return nr_free_pages() - nr_free_highpages();
+}
+
+/*
+ * Number of pages required to be kept free while writing the image. Always
+ * half of all available low pages before the writing starts.
+ */
+static inline unsigned long reqd_free_pages(void)
+{
+	return low_free_pages() / 2;
+}
+
+struct swap_map_page {
+	sector_t entries[MAP_PAGE_ENTRIES];
+	sector_t next_swap;
+};
+
+struct swap_map_page_list {
+	struct swap_map_page *map;
+	struct swap_map_page_list *next;
+};
+
+/*
+ *	The swap_map_handle structure is used for handling swap in
+ *	a file-alike way
+ */
+
+struct swap_map_handle {
+	struct swap_map_page *cur;
+	struct swap_map_page_list *maps;
+	sector_t cur_swap;
+	sector_t first_sector;
+	unsigned int k;
+	unsigned long reqd_free_pages;
+	u32 crc32;
+};
+
+struct swsusp_header {
+	char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int) -
+	              sizeof(u32) - sizeof(u32)];
+	u32	hw_sig;
+	u32	crc32;
+	sector_t image;
+	unsigned int flags;	/* Flags to pass to the "boot" kernel */
+	char	orig_sig[10];
+	char	sig[10];
+} __packed;
+
+static struct swsusp_header *swsusp_header;
+
+/*
+ *	The following functions are used for tracing the allocated
+ *	swap pages, so that they can be freed in case of an error.
+ */
+
+struct swsusp_extent {
+	struct rb_node node;
+	unsigned long start;
+	unsigned long end;
+};
+
+static struct rb_root swsusp_extents = RB_ROOT;
+
+static int swsusp_extents_insert(unsigned long swap_offset)
+{
+	struct rb_node **new = &(swsusp_extents.rb_node);
+	struct rb_node *parent = NULL;
+	struct swsusp_extent *ext;
+
+	/* Figure out where to put the new node */
+	while (*new) {
+		ext = rb_entry(*new, struct swsusp_extent, node);
+		parent = *new;
+		if (swap_offset < ext->start) {
+			/* Try to merge */
+			if (swap_offset == ext->start - 1) {
+				ext->start--;
+				return 0;
+			}
+			new = &((*new)->rb_left);
+		} else if (swap_offset > ext->end) {
+			/* Try to merge */
+			if (swap_offset == ext->end + 1) {
+				ext->end++;
+				return 0;
+			}
+			new = &((*new)->rb_right);
+		} else {
+			/* It already is in the tree */
+			return -EINVAL;
+		}
+	}
+	/* Add the new node and rebalance the tree. */
+	ext = kzalloc(sizeof(struct swsusp_extent), GFP_KERNEL);
+	if (!ext)
+		return -ENOMEM;
+
+	ext->start = swap_offset;
+	ext->end = swap_offset;
+	rb_link_node(&ext->node, parent, new);
+	rb_insert_color(&ext->node, &swsusp_extents);
+	return 0;
+}
+
+/*
+ *	alloc_swapdev_block - allocate a swap page and register that it has
+ *	been allocated, so that it can be freed in case of an error.
+ */
+
+sector_t alloc_swapdev_block(int swap)
+{
+	unsigned long offset;
+
+	offset = swp_offset(get_swap_page_of_type(swap));
+	if (offset) {
+		if (swsusp_extents_insert(offset))
+			swap_free(swp_entry(swap, offset));
+		else
+			return swapdev_block(swap, offset);
+	}
+	return 0;
+}
+
+/*
+ *	free_all_swap_pages - free swap pages allocated for saving image data.
+ *	It also frees the extents used to register which swap entries had been
+ *	allocated.
+ */
+
+void free_all_swap_pages(int swap)
+{
+	struct rb_node *node;
+
+	while ((node = swsusp_extents.rb_node)) {
+		struct swsusp_extent *ext;
+		unsigned long offset;
+
+		ext = rb_entry(node, struct swsusp_extent, node);
+		rb_erase(node, &swsusp_extents);
+		for (offset = ext->start; offset <= ext->end; offset++)
+			swap_free(swp_entry(swap, offset));
+
+		kfree(ext);
+	}
+}
+
+int swsusp_swap_in_use(void)
+{
+	return (swsusp_extents.rb_node != NULL);
+}
+
+/*
+ * General things
+ */
+
+static unsigned short root_swap = 0xffff;
+static struct block_device *hib_resume_bdev;
+
+struct hib_bio_batch {
+	atomic_t		count;
+	wait_queue_head_t	wait;
+	blk_status_t		error;
+	struct blk_plug		plug;
+};
+
+static void hib_init_batch(struct hib_bio_batch *hb)
+{
+	atomic_set(&hb->count, 0);
+	init_waitqueue_head(&hb->wait);
+	hb->error = BLK_STS_OK;
+	blk_start_plug(&hb->plug);
+}
+
+static void hib_finish_batch(struct hib_bio_batch *hb)
+{
+	blk_finish_plug(&hb->plug);
+}
+
+static void hib_end_io(struct bio *bio)
+{
+	struct hib_bio_batch *hb = bio->bi_private;
+	struct page *page = bio_first_page_all(bio);
+
+	if (bio->bi_status) {
+		pr_alert("Read-error on swap-device (%u:%u:%Lu)\n",
+			 MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
+			 (unsigned long long)bio->bi_iter.bi_sector);
+	}
+
+	if (bio_data_dir(bio) == WRITE)
+		put_page(page);
+	else if (clean_pages_on_read)
+		flush_icache_range((unsigned long)page_address(page),
+				   (unsigned long)page_address(page) + PAGE_SIZE);
+
+	if (bio->bi_status && !hb->error)
+		hb->error = bio->bi_status;
+	if (atomic_dec_and_test(&hb->count))
+		wake_up(&hb->wait);
+
+	bio_put(bio);
+}
+
+static int hib_submit_io(blk_opf_t opf, pgoff_t page_off, void *addr,
+			 struct hib_bio_batch *hb)
+{
+	struct page *page = virt_to_page(addr);
+	struct bio *bio;
+	int error = 0;
+
+	bio = bio_alloc(hib_resume_bdev, 1, opf, GFP_NOIO | __GFP_HIGH);
+	bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9);
+
+	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
+		pr_err("Adding page to bio failed at %llu\n",
+		       (unsigned long long)bio->bi_iter.bi_sector);
+		bio_put(bio);
+		return -EFAULT;
+	}
+
+	if (hb) {
+		bio->bi_end_io = hib_end_io;
+		bio->bi_private = hb;
+		atomic_inc(&hb->count);
+		submit_bio(bio);
+	} else {
+		error = submit_bio_wait(bio);
+		bio_put(bio);
+	}
+
+	return error;
+}
+
+static int hib_wait_io(struct hib_bio_batch *hb)
+{
+	/*
+	 * We are relying on the behavior of blk_plug that a thread with
+	 * a plug will flush the plug list before sleeping.
+	 */
+	wait_event(hb->wait, atomic_read(&hb->count) == 0);
+	return blk_status_to_errno(hb->error);
+}
+
+/*
+ * Saving part
+ */
+static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
+{
+	int error;
+
+	hib_submit_io(REQ_OP_READ, swsusp_resume_block, swsusp_header, NULL);
+	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
+	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
+		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
+		memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
+		swsusp_header->image = handle->first_sector;
+		if (swsusp_hardware_signature) {
+			swsusp_header->hw_sig = swsusp_hardware_signature;
+			flags |= SF_HW_SIG;
+		}
+		swsusp_header->flags = flags;
+		if (flags & SF_CRC32_MODE)
+			swsusp_header->crc32 = handle->crc32;
+		error = hib_submit_io(REQ_OP_WRITE | REQ_SYNC,
+				      swsusp_resume_block, swsusp_header, NULL);
+	} else {
+		pr_err("Swap header not found!\n");
+		error = -ENODEV;
+	}
+	return error;
+}
+
+/**
+ *	swsusp_swap_check - check if the resume device is a swap device
+ *	and get its index (if so)
+ *
+ *	This is called before saving image
+ */
+static int swsusp_swap_check(void)
+{
+	int res;
+
+	if (swsusp_resume_device)
+		res = swap_type_of(swsusp_resume_device, swsusp_resume_block);
+	else
+		res = find_first_swap(&swsusp_resume_device);
+	if (res < 0)
+		return res;
+	root_swap = res;
+
+	hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device, FMODE_WRITE,
+			NULL);
+	if (IS_ERR(hib_resume_bdev))
+		return PTR_ERR(hib_resume_bdev);
+
+	res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
+	if (res < 0)
+		blkdev_put(hib_resume_bdev, FMODE_WRITE);
+
+	return res;
+}
+
+/**
+ *	write_page - Write one page to given swap location.
+ *	@buf:		Address we're writing.
+ *	@offset:	Offset of the swap page we're writing to.
+ *	@hb:		bio completion batch
+ */
+
+static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb)
+{
+	void *src;
+	int ret;
+
+	if (!offset)
+		return -ENOSPC;
+
+	if (hb) {
+		src = (void *)__get_free_page(GFP_NOIO | __GFP_NOWARN |
+		                              __GFP_NORETRY);
+		if (src) {
+			copy_page(src, buf);
+		} else {
+			ret = hib_wait_io(hb); /* Free pages */
+			if (ret)
+				return ret;
+			src = (void *)__get_free_page(GFP_NOIO |
+			                              __GFP_NOWARN |
+			                              __GFP_NORETRY);
+			if (src) {
+				copy_page(src, buf);
+			} else {
+				WARN_ON_ONCE(1);
+				hb = NULL;	/* Go synchronous */
+				src = buf;
+			}
+		}
+	} else {
+		src = buf;
+	}
+	return hib_submit_io(REQ_OP_WRITE | REQ_SYNC, offset, src, hb);
+}
+
+static void release_swap_writer(struct swap_map_handle *handle)
+{
+	if (handle->cur)
+		free_page((unsigned long)handle->cur);
+	handle->cur = NULL;
+}
+
+static int get_swap_writer(struct swap_map_handle *handle)
+{
+	int ret;
+
+	ret = swsusp_swap_check();
+	if (ret) {
+		if (ret != -ENOSPC)
+			pr_err("Cannot find swap device, try swapon -a\n");
+		return ret;
+	}
+	handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
+	if (!handle->cur) {
+		ret = -ENOMEM;
+		goto err_close;
+	}
+	handle->cur_swap = alloc_swapdev_block(root_swap);
+	if (!handle->cur_swap) {
+		ret = -ENOSPC;
+		goto err_rel;
+	}
+	handle->k = 0;
+	handle->reqd_free_pages = reqd_free_pages();
+	handle->first_sector = handle->cur_swap;
+	return 0;
+err_rel:
+	release_swap_writer(handle);
+err_close:
+	swsusp_close(FMODE_WRITE);
+	return ret;
+}
+
+static int swap_write_page(struct swap_map_handle *handle, void *buf,
+		struct hib_bio_batch *hb)
+{
+	int error = 0;
+	sector_t offset;
+
+	if (!handle->cur)
+		return -EINVAL;
+	offset = alloc_swapdev_block(root_swap);
+	error = write_page(buf, offset, hb);
+	if (error)
+		return error;
+	handle->cur->entries[handle->k++] = offset;
+	if (handle->k >= MAP_PAGE_ENTRIES) {
+		offset = alloc_swapdev_block(root_swap);
+		if (!offset)
+			return -ENOSPC;
+		handle->cur->next_swap = offset;
+		error = write_page(handle->cur, handle->cur_swap, hb);
+		if (error)
+			goto out;
+		clear_page(handle->cur);
+		handle->cur_swap = offset;
+		handle->k = 0;
+
+		if (hb && low_free_pages() <= handle->reqd_free_pages) {
+			error = hib_wait_io(hb);
+			if (error)
+				goto out;
+			/*
+			 * Recalculate the number of required free pages, to
+			 * make sure we never take more than half.
+			 */
+			handle->reqd_free_pages = reqd_free_pages();
+		}
+	}
+ out:
+	return error;
+}
+
+static int flush_swap_writer(struct swap_map_handle *handle)
+{
+	if (handle->cur && handle->cur_swap)
+		return write_page(handle->cur, handle->cur_swap, NULL);
+	else
+		return -EINVAL;
+}
+
+static int swap_writer_finish(struct swap_map_handle *handle,
+		unsigned int flags, int error)
+{
+	if (!error) {
+		pr_info("S");
+		error = mark_swapfiles(handle, flags);
+		pr_cont("|\n");
+		flush_swap_writer(handle);
+	}
+
+	if (error)
+		free_all_swap_pages(root_swap);
+	release_swap_writer(handle);
+	swsusp_close(FMODE_WRITE);
+
+	return error;
+}
+
+/* We need to remember how much compressed data we need to read. */
+#define LZO_HEADER	sizeof(size_t)
+
+/* Number of pages/bytes we'll compress at one time. */
+#define LZO_UNC_PAGES	32
+#define LZO_UNC_SIZE	(LZO_UNC_PAGES * PAGE_SIZE)
+
+/* Number of pages/bytes we need for compressed data (worst case). */
+#define LZO_CMP_PAGES	DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
+			             LZO_HEADER, PAGE_SIZE)
+#define LZO_CMP_SIZE	(LZO_CMP_PAGES * PAGE_SIZE)
+
+/* Maximum number of threads for compression/decompression. */
+#define LZO_THREADS	3
+
+/* Minimum/maximum number of pages for read buffering. */
+#define LZO_MIN_RD_PAGES	1024
+#define LZO_MAX_RD_PAGES	8192
+
+
+/**
+ *	save_image - save the suspend image data
+ */
+
+static int save_image(struct swap_map_handle *handle,
+                      struct snapshot_handle *snapshot,
+                      unsigned int nr_to_write)
+{
+	unsigned int m;
+	int ret;
+	int nr_pages;
+	int err2;
+	struct hib_bio_batch hb;
+	ktime_t start;
+	ktime_t stop;
+
+	hib_init_batch(&hb);
+
+	pr_info("Saving image data pages (%u pages)...\n",
+		nr_to_write);
+	m = nr_to_write / 10;
+	if (!m)
+		m = 1;
+	nr_pages = 0;
+	start = ktime_get();
+	while (1) {
+		ret = snapshot_read_next(snapshot);
+		if (ret <= 0)
+			break;
+		ret = swap_write_page(handle, data_of(*snapshot), &hb);
+		if (ret)
+			break;
+		if (!(nr_pages % m))
+			pr_info("Image saving progress: %3d%%\n",
+				nr_pages / m * 10);
+		nr_pages++;
+	}
+	err2 = hib_wait_io(&hb);
+	hib_finish_batch(&hb);
+	stop = ktime_get();
+	if (!ret)
+		ret = err2;
+	if (!ret)
+		pr_info("Image saving done\n");
+	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
+	return ret;
+}
+
+/**
+ * Structure used for CRC32.
+ */
+struct crc_data {
+	struct task_struct *thr;                  /* thread */
+	atomic_t ready;                           /* ready to start flag */
+	atomic_t stop;                            /* ready to stop flag */
+	unsigned run_threads;                     /* nr current threads */
+	wait_queue_head_t go;                     /* start crc update */
+	wait_queue_head_t done;                   /* crc update done */
+	u32 *crc32;                               /* points to handle's crc32 */
+	size_t *unc_len[LZO_THREADS];             /* uncompressed lengths */
+	unsigned char *unc[LZO_THREADS];          /* uncompressed data */
+};
+
+/**
+ * CRC32 update function that runs in its own thread.
+ */
+static int crc32_threadfn(void *data)
+{
+	struct crc_data *d = data;
+	unsigned i;
+
+	while (1) {
+		wait_event(d->go, atomic_read_acquire(&d->ready) ||
+		                  kthread_should_stop());
+		if (kthread_should_stop()) {
+			d->thr = NULL;
+			atomic_set_release(&d->stop, 1);
+			wake_up(&d->done);
+			break;
+		}
+		atomic_set(&d->ready, 0);
+
+		for (i = 0; i < d->run_threads; i++)
+			*d->crc32 = crc32_le(*d->crc32,
+			                     d->unc[i], *d->unc_len[i]);
+		atomic_set_release(&d->stop, 1);
+		wake_up(&d->done);
+	}
+	return 0;
+}
+/**
+ * Structure used for LZO data compression.
+ */
+struct cmp_data {
+	struct task_struct *thr;                  /* thread */
+	atomic_t ready;                           /* ready to start flag */
+	atomic_t stop;                            /* ready to stop flag */
+	int ret;                                  /* return code */
+	wait_queue_head_t go;                     /* start compression */
+	wait_queue_head_t done;                   /* compression done */
+	size_t unc_len;                           /* uncompressed length */
+	size_t cmp_len;                           /* compressed length */
+	unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
+	unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
+	unsigned char wrk[LZO1X_1_MEM_COMPRESS];  /* compression workspace */
+};
+
+/**
+ * Compression function that runs in its own thread.
+ */
+static int lzo_compress_threadfn(void *data)
+{
+	struct cmp_data *d = data;
+
+	while (1) {
+		wait_event(d->go, atomic_read_acquire(&d->ready) ||
+		                  kthread_should_stop());
+		if (kthread_should_stop()) {
+			d->thr = NULL;
+			d->ret = -1;
+			atomic_set_release(&d->stop, 1);
+			wake_up(&d->done);
+			break;
+		}
+		atomic_set(&d->ready, 0);
+
+		d->ret = lzo1x_1_compress(d->unc, d->unc_len,
+		                          d->cmp + LZO_HEADER, &d->cmp_len,
+		                          d->wrk);
+		atomic_set_release(&d->stop, 1);
+		wake_up(&d->done);
+	}
+	return 0;
+}
+
+/**
+ * save_image_lzo - Save the suspend image data compressed with LZO.
+ * @handle: Swap map handle to use for saving the image.
+ * @snapshot: Image to read data from.
+ * @nr_to_write: Number of pages to save.
+ */
+static int save_image_lzo(struct swap_map_handle *handle,
+                          struct snapshot_handle *snapshot,
+                          unsigned int nr_to_write)
+{
+	unsigned int m;
+	int ret = 0;
+	int nr_pages;
+	int err2;
+	struct hib_bio_batch hb;
+	ktime_t start;
+	ktime_t stop;
+	size_t off;
+	unsigned thr, run_threads, nr_threads;
+	unsigned char *page = NULL;
+	struct cmp_data *data = NULL;
+	struct crc_data *crc = NULL;
+
+	hib_init_batch(&hb);
+
+	/*
+	 * We'll limit the number of threads for compression to limit memory
+	 * footprint.
+	 */
+	nr_threads = num_online_cpus() - 1;
+	nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
+
+	page = (void *)__get_free_page(GFP_NOIO | __GFP_HIGH);
+	if (!page) {
+		pr_err("Failed to allocate LZO page\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	data = vzalloc(array_size(nr_threads, sizeof(*data)));
+	if (!data) {
+		pr_err("Failed to allocate LZO data\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	crc = kzalloc(sizeof(*crc), GFP_KERNEL);
+	if (!crc) {
+		pr_err("Failed to allocate crc\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	/*
+	 * Start the compression threads.
+	 */
+	for (thr = 0; thr < nr_threads; thr++) {
+		init_waitqueue_head(&data[thr].go);
+		init_waitqueue_head(&data[thr].done);
+
+		data[thr].thr = kthread_run(lzo_compress_threadfn,
+		                            &data[thr],
+		                            "image_compress/%u", thr);
+		if (IS_ERR(data[thr].thr)) {
+			data[thr].thr = NULL;
+			pr_err("Cannot start compression threads\n");
+			ret = -ENOMEM;
+			goto out_clean;
+		}
+	}
+
+	/*
+	 * Start the CRC32 thread.
+	 */
+	init_waitqueue_head(&crc->go);
+	init_waitqueue_head(&crc->done);
+
+	handle->crc32 = 0;
+	crc->crc32 = &handle->crc32;
+	for (thr = 0; thr < nr_threads; thr++) {
+		crc->unc[thr] = data[thr].unc;
+		crc->unc_len[thr] = &data[thr].unc_len;
+	}
+
+	crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
+	if (IS_ERR(crc->thr)) {
+		crc->thr = NULL;
+		pr_err("Cannot start CRC32 thread\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	/*
+	 * Adjust the number of required free pages after all allocations have
+	 * been done. We don't want to run out of pages when writing.
+	 */
+	handle->reqd_free_pages = reqd_free_pages();
+
+	pr_info("Using %u thread(s) for compression\n", nr_threads);
+	pr_info("Compressing and saving image data (%u pages)...\n",
+		nr_to_write);
+	m = nr_to_write / 10;
+	if (!m)
+		m = 1;
+	nr_pages = 0;
+	start = ktime_get();
+	for (;;) {
+		for (thr = 0; thr < nr_threads; thr++) {
+			for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
+				ret = snapshot_read_next(snapshot);
+				if (ret < 0)
+					goto out_finish;
+
+				if (!ret)
+					break;
+
+				memcpy(data[thr].unc + off,
+				       data_of(*snapshot), PAGE_SIZE);
+
+				if (!(nr_pages % m))
+					pr_info("Image saving progress: %3d%%\n",
+						nr_pages / m * 10);
+				nr_pages++;
+			}
+			if (!off)
+				break;
+
+			data[thr].unc_len = off;
+
+			atomic_set_release(&data[thr].ready, 1);
+			wake_up(&data[thr].go);
+		}
+
+		if (!thr)
+			break;
+
+		crc->run_threads = thr;
+		atomic_set_release(&crc->ready, 1);
+		wake_up(&crc->go);
+
+		for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
+			wait_event(data[thr].done,
+				atomic_read_acquire(&data[thr].stop));
+			atomic_set(&data[thr].stop, 0);
+
+			ret = data[thr].ret;
+
+			if (ret < 0) {
+				pr_err("LZO compression failed\n");
+				goto out_finish;
+			}
+
+			if (unlikely(!data[thr].cmp_len ||
+			             data[thr].cmp_len >
+			             lzo1x_worst_compress(data[thr].unc_len))) {
+				pr_err("Invalid LZO compressed length\n");
+				ret = -1;
+				goto out_finish;
+			}
+
+			*(size_t *)data[thr].cmp = data[thr].cmp_len;
+
+			/*
+			 * Given we are writing one page at a time to disk, we
+			 * copy that much from the buffer, although the last
+			 * bit will likely be smaller than full page. This is
+			 * OK - we saved the length of the compressed data, so
+			 * any garbage at the end will be discarded when we
+			 * read it.
+			 */
+			for (off = 0;
+			     off < LZO_HEADER + data[thr].cmp_len;
+			     off += PAGE_SIZE) {
+				memcpy(page, data[thr].cmp + off, PAGE_SIZE);
+
+				ret = swap_write_page(handle, page, &hb);
+				if (ret)
+					goto out_finish;
+			}
+		}
+
+		wait_event(crc->done, atomic_read_acquire(&crc->stop));
+		atomic_set(&crc->stop, 0);
+	}
+
+out_finish:
+	err2 = hib_wait_io(&hb);
+	stop = ktime_get();
+	if (!ret)
+		ret = err2;
+	if (!ret)
+		pr_info("Image saving done\n");
+	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
+out_clean:
+	hib_finish_batch(&hb);
+	if (crc) {
+		if (crc->thr)
+			kthread_stop(crc->thr);
+		kfree(crc);
+	}
+	if (data) {
+		for (thr = 0; thr < nr_threads; thr++)
+			if (data[thr].thr)
+				kthread_stop(data[thr].thr);
+		vfree(data);
+	}
+	if (page) free_page((unsigned long)page);
+
+	return ret;
+}
+
+/**
+ *	enough_swap - Make sure we have enough swap to save the image.
+ *
+ *	Returns TRUE or FALSE after checking the total amount of swap
+ *	space available from the resume partition.
+ */
+
+static int enough_swap(unsigned int nr_pages)
+{
+	unsigned int free_swap = count_swap_pages(root_swap, 1);
+	unsigned int required;
+
+	pr_debug("Free swap pages: %u\n", free_swap);
+
+	required = PAGES_FOR_IO + nr_pages;
+	return free_swap > required;
+}
+
+/**
+ *	swsusp_write - Write entire image and metadata.
+ *	@flags: flags to pass to the "boot" kernel in the image header
+ *
+ *	It is important _NOT_ to umount filesystems at this point. We want
+ *	them synced (in case something goes wrong) but we DO not want to mark
+ *	filesystem clean: it is not. (And it does not matter, if we resume
+ *	correctly, we'll mark system clean, anyway.)
+ */
+
+int swsusp_write(unsigned int flags)
+{
+	struct swap_map_handle handle;
+	struct snapshot_handle snapshot;
+	struct swsusp_info *header;
+	unsigned long pages;
+	int error;
+
+	pages = snapshot_get_image_size();
+	error = get_swap_writer(&handle);
+	if (error) {
+		pr_err("Cannot get swap writer\n");
+		return error;
+	}
+	if (flags & SF_NOCOMPRESS_MODE) {
+		if (!enough_swap(pages)) {
+			pr_err("Not enough free swap\n");
+			error = -ENOSPC;
+			goto out_finish;
+		}
+	}
+	memset(&snapshot, 0, sizeof(struct snapshot_handle));
+	error = snapshot_read_next(&snapshot);
+	if (error < (int)PAGE_SIZE) {
+		if (error >= 0)
+			error = -EFAULT;
+
+		goto out_finish;
+	}
+	header = (struct swsusp_info *)data_of(snapshot);
+	error = swap_write_page(&handle, header, NULL);
+	if (!error) {
+		error = (flags & SF_NOCOMPRESS_MODE) ?
+			save_image(&handle, &snapshot, pages - 1) :
+			save_image_lzo(&handle, &snapshot, pages - 1);
+	}
+out_finish:
+	error = swap_writer_finish(&handle, flags, error);
+	return error;
+}
+
+/**
+ *	The following functions allow us to read data using a swap map
+ *	in a file-alike way
+ */
+
+static void release_swap_reader(struct swap_map_handle *handle)
+{
+	struct swap_map_page_list *tmp;
+
+	while (handle->maps) {
+		if (handle->maps->map)
+			free_page((unsigned long)handle->maps->map);
+		tmp = handle->maps;
+		handle->maps = handle->maps->next;
+		kfree(tmp);
+	}
+	handle->cur = NULL;
+}
+
+static int get_swap_reader(struct swap_map_handle *handle,
+		unsigned int *flags_p)
+{
+	int error;
+	struct swap_map_page_list *tmp, *last;
+	sector_t offset;
+
+	*flags_p = swsusp_header->flags;
+
+	if (!swsusp_header->image) /* how can this happen? */
+		return -EINVAL;
+
+	handle->cur = NULL;
+	last = handle->maps = NULL;
+	offset = swsusp_header->image;
+	while (offset) {
+		tmp = kzalloc(sizeof(*handle->maps), GFP_KERNEL);
+		if (!tmp) {
+			release_swap_reader(handle);
+			return -ENOMEM;
+		}
+		if (!handle->maps)
+			handle->maps = tmp;
+		if (last)
+			last->next = tmp;
+		last = tmp;
+
+		tmp->map = (struct swap_map_page *)
+			   __get_free_page(GFP_NOIO | __GFP_HIGH);
+		if (!tmp->map) {
+			release_swap_reader(handle);
+			return -ENOMEM;
+		}
+
+		error = hib_submit_io(REQ_OP_READ, offset, tmp->map, NULL);
+		if (error) {
+			release_swap_reader(handle);
+			return error;
+		}
+		offset = tmp->map->next_swap;
+	}
+	handle->k = 0;
+	handle->cur = handle->maps->map;
+	return 0;
+}
+
+static int swap_read_page(struct swap_map_handle *handle, void *buf,
+		struct hib_bio_batch *hb)
+{
+	sector_t offset;
+	int error;
+	struct swap_map_page_list *tmp;
+
+	if (!handle->cur)
+		return -EINVAL;
+	offset = handle->cur->entries[handle->k];
+	if (!offset)
+		return -EFAULT;
+	error = hib_submit_io(REQ_OP_READ, offset, buf, hb);
+	if (error)
+		return error;
+	if (++handle->k >= MAP_PAGE_ENTRIES) {
+		handle->k = 0;
+		free_page((unsigned long)handle->maps->map);
+		tmp = handle->maps;
+		handle->maps = handle->maps->next;
+		kfree(tmp);
+		if (!handle->maps)
+			release_swap_reader(handle);
+		else
+			handle->cur = handle->maps->map;
+	}
+	return error;
+}
+
+static int swap_reader_finish(struct swap_map_handle *handle)
+{
+	release_swap_reader(handle);
+
+	return 0;
+}
+
+/**
+ *	load_image - load the image using the swap map handle
+ *	@handle and the snapshot handle @snapshot
+ *	(assume there are @nr_pages pages to load)
+ */
+
+static int load_image(struct swap_map_handle *handle,
+                      struct snapshot_handle *snapshot,
+                      unsigned int nr_to_read)
+{
+	unsigned int m;
+	int ret = 0;
+	ktime_t start;
+	ktime_t stop;
+	struct hib_bio_batch hb;
+	int err2;
+	unsigned nr_pages;
+
+	hib_init_batch(&hb);
+
+	clean_pages_on_read = true;
+	pr_info("Loading image data pages (%u pages)...\n", nr_to_read);
+	m = nr_to_read / 10;
+	if (!m)
+		m = 1;
+	nr_pages = 0;
+	start = ktime_get();
+	for ( ; ; ) {
+		ret = snapshot_write_next(snapshot);
+		if (ret <= 0)
+			break;
+		ret = swap_read_page(handle, data_of(*snapshot), &hb);
+		if (ret)
+			break;
+		if (snapshot->sync_read)
+			ret = hib_wait_io(&hb);
+		if (ret)
+			break;
+		if (!(nr_pages % m))
+			pr_info("Image loading progress: %3d%%\n",
+				nr_pages / m * 10);
+		nr_pages++;
+	}
+	err2 = hib_wait_io(&hb);
+	hib_finish_batch(&hb);
+	stop = ktime_get();
+	if (!ret)
+		ret = err2;
+	if (!ret) {
+		pr_info("Image loading done\n");
+		snapshot_write_finalize(snapshot);
+		if (!snapshot_image_loaded(snapshot))
+			ret = -ENODATA;
+	}
+	swsusp_show_speed(start, stop, nr_to_read, "Read");
+	return ret;
+}
+
+/**
+ * Structure used for LZO data decompression.
+ */
+struct dec_data {
+	struct task_struct *thr;                  /* thread */
+	atomic_t ready;                           /* ready to start flag */
+	atomic_t stop;                            /* ready to stop flag */
+	int ret;                                  /* return code */
+	wait_queue_head_t go;                     /* start decompression */
+	wait_queue_head_t done;                   /* decompression done */
+	size_t unc_len;                           /* uncompressed length */
+	size_t cmp_len;                           /* compressed length */
+	unsigned char unc[LZO_UNC_SIZE];          /* uncompressed buffer */
+	unsigned char cmp[LZO_CMP_SIZE];          /* compressed buffer */
+};
+
+/**
+ * Decompression function that runs in its own thread.
+ */
+static int lzo_decompress_threadfn(void *data)
+{
+	struct dec_data *d = data;
+
+	while (1) {
+		wait_event(d->go, atomic_read_acquire(&d->ready) ||
+		                  kthread_should_stop());
+		if (kthread_should_stop()) {
+			d->thr = NULL;
+			d->ret = -1;
+			atomic_set_release(&d->stop, 1);
+			wake_up(&d->done);
+			break;
+		}
+		atomic_set(&d->ready, 0);
+
+		d->unc_len = LZO_UNC_SIZE;
+		d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
+		                               d->unc, &d->unc_len);
+		if (clean_pages_on_decompress)
+			flush_icache_range((unsigned long)d->unc,
+					   (unsigned long)d->unc + d->unc_len);
+
+		atomic_set_release(&d->stop, 1);
+		wake_up(&d->done);
+	}
+	return 0;
+}
+
+/**
+ * load_image_lzo - Load compressed image data and decompress them with LZO.
+ * @handle: Swap map handle to use for loading data.
+ * @snapshot: Image to copy uncompressed data into.
+ * @nr_to_read: Number of pages to load.
+ */
+static int load_image_lzo(struct swap_map_handle *handle,
+                          struct snapshot_handle *snapshot,
+                          unsigned int nr_to_read)
+{
+	unsigned int m;
+	int ret = 0;
+	int eof = 0;
+	struct hib_bio_batch hb;
+	ktime_t start;
+	ktime_t stop;
+	unsigned nr_pages;
+	size_t off;
+	unsigned i, thr, run_threads, nr_threads;
+	unsigned ring = 0, pg = 0, ring_size = 0,
+	         have = 0, want, need, asked = 0;
+	unsigned long read_pages = 0;
+	unsigned char **page = NULL;
+	struct dec_data *data = NULL;
+	struct crc_data *crc = NULL;
+
+	hib_init_batch(&hb);
+
+	/*
+	 * We'll limit the number of threads for decompression to limit memory
+	 * footprint.
+	 */
+	nr_threads = num_online_cpus() - 1;
+	nr_threads = clamp_val(nr_threads, 1, LZO_THREADS);
+
+	page = vmalloc(array_size(LZO_MAX_RD_PAGES, sizeof(*page)));
+	if (!page) {
+		pr_err("Failed to allocate LZO page\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	data = vzalloc(array_size(nr_threads, sizeof(*data)));
+	if (!data) {
+		pr_err("Failed to allocate LZO data\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	crc = kzalloc(sizeof(*crc), GFP_KERNEL);
+	if (!crc) {
+		pr_err("Failed to allocate crc\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	clean_pages_on_decompress = true;
+
+	/*
+	 * Start the decompression threads.
+	 */
+	for (thr = 0; thr < nr_threads; thr++) {
+		init_waitqueue_head(&data[thr].go);
+		init_waitqueue_head(&data[thr].done);
+
+		data[thr].thr = kthread_run(lzo_decompress_threadfn,
+		                            &data[thr],
+		                            "image_decompress/%u", thr);
+		if (IS_ERR(data[thr].thr)) {
+			data[thr].thr = NULL;
+			pr_err("Cannot start decompression threads\n");
+			ret = -ENOMEM;
+			goto out_clean;
+		}
+	}
+
+	/*
+	 * Start the CRC32 thread.
+	 */
+	init_waitqueue_head(&crc->go);
+	init_waitqueue_head(&crc->done);
+
+	handle->crc32 = 0;
+	crc->crc32 = &handle->crc32;
+	for (thr = 0; thr < nr_threads; thr++) {
+		crc->unc[thr] = data[thr].unc;
+		crc->unc_len[thr] = &data[thr].unc_len;
+	}
+
+	crc->thr = kthread_run(crc32_threadfn, crc, "image_crc32");
+	if (IS_ERR(crc->thr)) {
+		crc->thr = NULL;
+		pr_err("Cannot start CRC32 thread\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	/*
+	 * Set the number of pages for read buffering.
+	 * This is complete guesswork, because we'll only know the real
+	 * picture once prepare_image() is called, which is much later on
+	 * during the image load phase. We'll assume the worst case and
+	 * say that none of the image pages are from high memory.
+	 */
+	if (low_free_pages() > snapshot_get_image_size())
+		read_pages = (low_free_pages() - snapshot_get_image_size()) / 2;
+	read_pages = clamp_val(read_pages, LZO_MIN_RD_PAGES, LZO_MAX_RD_PAGES);
+
+	for (i = 0; i < read_pages; i++) {
+		page[i] = (void *)__get_free_page(i < LZO_CMP_PAGES ?
+						  GFP_NOIO | __GFP_HIGH :
+						  GFP_NOIO | __GFP_NOWARN |
+						  __GFP_NORETRY);
+
+		if (!page[i]) {
+			if (i < LZO_CMP_PAGES) {
+				ring_size = i;
+				pr_err("Failed to allocate LZO pages\n");
+				ret = -ENOMEM;
+				goto out_clean;
+			} else {
+				break;
+			}
+		}
+	}
+	want = ring_size = i;
+
+	pr_info("Using %u thread(s) for decompression\n", nr_threads);
+	pr_info("Loading and decompressing image data (%u pages)...\n",
+		nr_to_read);
+	m = nr_to_read / 10;
+	if (!m)
+		m = 1;
+	nr_pages = 0;
+	start = ktime_get();
+
+	ret = snapshot_write_next(snapshot);
+	if (ret <= 0)
+		goto out_finish;
+
+	for(;;) {
+		for (i = 0; !eof && i < want; i++) {
+			ret = swap_read_page(handle, page[ring], &hb);
+			if (ret) {
+				/*
+				 * On real read error, finish. On end of data,
+				 * set EOF flag and just exit the read loop.
+				 */
+				if (handle->cur &&
+				    handle->cur->entries[handle->k]) {
+					goto out_finish;
+				} else {
+					eof = 1;
+					break;
+				}
+			}
+			if (++ring >= ring_size)
+				ring = 0;
+		}
+		asked += i;
+		want -= i;
+
+		/*
+		 * We are out of data, wait for some more.
+		 */
+		if (!have) {
+			if (!asked)
+				break;
+
+			ret = hib_wait_io(&hb);
+			if (ret)
+				goto out_finish;
+			have += asked;
+			asked = 0;
+			if (eof)
+				eof = 2;
+		}
+
+		if (crc->run_threads) {
+			wait_event(crc->done, atomic_read_acquire(&crc->stop));
+			atomic_set(&crc->stop, 0);
+			crc->run_threads = 0;
+		}
+
+		for (thr = 0; have && thr < nr_threads; thr++) {
+			data[thr].cmp_len = *(size_t *)page[pg];
+			if (unlikely(!data[thr].cmp_len ||
+			             data[thr].cmp_len >
+			             lzo1x_worst_compress(LZO_UNC_SIZE))) {
+				pr_err("Invalid LZO compressed length\n");
+				ret = -1;
+				goto out_finish;
+			}
+
+			need = DIV_ROUND_UP(data[thr].cmp_len + LZO_HEADER,
+			                    PAGE_SIZE);
+			if (need > have) {
+				if (eof > 1) {
+					ret = -1;
+					goto out_finish;
+				}
+				break;
+			}
+
+			for (off = 0;
+			     off < LZO_HEADER + data[thr].cmp_len;
+			     off += PAGE_SIZE) {
+				memcpy(data[thr].cmp + off,
+				       page[pg], PAGE_SIZE);
+				have--;
+				want++;
+				if (++pg >= ring_size)
+					pg = 0;
+			}
+
+			atomic_set_release(&data[thr].ready, 1);
+			wake_up(&data[thr].go);
+		}
+
+		/*
+		 * Wait for more data while we are decompressing.
+		 */
+		if (have < LZO_CMP_PAGES && asked) {
+			ret = hib_wait_io(&hb);
+			if (ret)
+				goto out_finish;
+			have += asked;
+			asked = 0;
+			if (eof)
+				eof = 2;
+		}
+
+		for (run_threads = thr, thr = 0; thr < run_threads; thr++) {
+			wait_event(data[thr].done,
+				atomic_read_acquire(&data[thr].stop));
+			atomic_set(&data[thr].stop, 0);
+
+			ret = data[thr].ret;
+
+			if (ret < 0) {
+				pr_err("LZO decompression failed\n");
+				goto out_finish;
+			}
+
+			if (unlikely(!data[thr].unc_len ||
+			             data[thr].unc_len > LZO_UNC_SIZE ||
+			             data[thr].unc_len & (PAGE_SIZE - 1))) {
+				pr_err("Invalid LZO uncompressed length\n");
+				ret = -1;
+				goto out_finish;
+			}
+
+			for (off = 0;
+			     off < data[thr].unc_len; off += PAGE_SIZE) {
+				memcpy(data_of(*snapshot),
+				       data[thr].unc + off, PAGE_SIZE);
+
+				if (!(nr_pages % m))
+					pr_info("Image loading progress: %3d%%\n",
+						nr_pages / m * 10);
+				nr_pages++;
+
+				ret = snapshot_write_next(snapshot);
+				if (ret <= 0) {
+					crc->run_threads = thr + 1;
+					atomic_set_release(&crc->ready, 1);
+					wake_up(&crc->go);
+					goto out_finish;
+				}
+			}
+		}
+
+		crc->run_threads = thr;
+		atomic_set_release(&crc->ready, 1);
+		wake_up(&crc->go);
+	}
+
+out_finish:
+	if (crc->run_threads) {
+		wait_event(crc->done, atomic_read_acquire(&crc->stop));
+		atomic_set(&crc->stop, 0);
+	}
+	stop = ktime_get();
+	if (!ret) {
+		pr_info("Image loading done\n");
+		snapshot_write_finalize(snapshot);
+		if (!snapshot_image_loaded(snapshot))
+			ret = -ENODATA;
+		if (!ret) {
+			if (swsusp_header->flags & SF_CRC32_MODE) {
+				if(handle->crc32 != swsusp_header->crc32) {
+					pr_err("Invalid image CRC32!\n");
+					ret = -ENODATA;
+				}
+			}
+		}
+	}
+	swsusp_show_speed(start, stop, nr_to_read, "Read");
+out_clean:
+	hib_finish_batch(&hb);
+	for (i = 0; i < ring_size; i++)
+		free_page((unsigned long)page[i]);
+	if (crc) {
+		if (crc->thr)
+			kthread_stop(crc->thr);
+		kfree(crc);
+	}
+	if (data) {
+		for (thr = 0; thr < nr_threads; thr++)
+			if (data[thr].thr)
+				kthread_stop(data[thr].thr);
+		vfree(data);
+	}
+	vfree(page);
+
+	return ret;
+}
+
+/**
+ *	swsusp_read - read the hibernation image.
+ *	@flags_p: flags passed by the "frozen" kernel in the image header should
+ *		  be written into this memory location
+ */
+
+int swsusp_read(unsigned int *flags_p)
+{
+	int error;
+	struct swap_map_handle handle;
+	struct snapshot_handle snapshot;
+	struct swsusp_info *header;
+
+	memset(&snapshot, 0, sizeof(struct snapshot_handle));
+	error = snapshot_write_next(&snapshot);
+	if (error < (int)PAGE_SIZE)
+		return error < 0 ? error : -EFAULT;
+	header = (struct swsusp_info *)data_of(snapshot);
+	error = get_swap_reader(&handle, flags_p);
+	if (error)
+		goto end;
+	if (!error)
+		error = swap_read_page(&handle, header, NULL);
+	if (!error) {
+		error = (*flags_p & SF_NOCOMPRESS_MODE) ?
+			load_image(&handle, &snapshot, header->pages - 1) :
+			load_image_lzo(&handle, &snapshot, header->pages - 1);
+	}
+	swap_reader_finish(&handle);
+end:
+	if (!error)
+		pr_debug("Image successfully loaded\n");
+	else
+		pr_debug("Error %d resuming\n", error);
+	return error;
+}
+
+/**
+ *      swsusp_check - Check for swsusp signature in the resume device
+ */
+
+int swsusp_check(void)
+{
+	int error;
+	void *holder;
+	fmode_t mode = FMODE_READ;
+
+	if (snapshot_test)
+		mode |= FMODE_EXCL;
+
+	hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
+					    mode, &holder);
+	if (!IS_ERR(hib_resume_bdev)) {
+		set_blocksize(hib_resume_bdev, PAGE_SIZE);
+		clear_page(swsusp_header);
+		error = hib_submit_io(REQ_OP_READ, swsusp_resume_block,
+					swsusp_header, NULL);
+		if (error)
+			goto put;
+
+		if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
+			memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
+			/* Reset swap signature now */
+			error = hib_submit_io(REQ_OP_WRITE | REQ_SYNC,
+						swsusp_resume_block,
+						swsusp_header, NULL);
+		} else {
+			error = -EINVAL;
+		}
+		if (!error && swsusp_header->flags & SF_HW_SIG &&
+		    swsusp_header->hw_sig != swsusp_hardware_signature) {
+			pr_info("Suspend image hardware signature mismatch (%08x now %08x); aborting resume.\n",
+				swsusp_header->hw_sig, swsusp_hardware_signature);
+			error = -EINVAL;
+		}
+
+put:
+		if (error)
+			blkdev_put(hib_resume_bdev, mode);
+		else
+			pr_debug("Image signature found, resuming\n");
+	} else {
+		error = PTR_ERR(hib_resume_bdev);
+	}
+
+	if (error)
+		pr_debug("Image not found (code %d)\n", error);
+
+	return error;
+}
+
+/**
+ *	swsusp_close - close swap device.
+ */
+
+void swsusp_close(fmode_t mode)
+{
+	if (IS_ERR(hib_resume_bdev)) {
+		pr_debug("Image device not initialised\n");
+		return;
+	}
+
+	blkdev_put(hib_resume_bdev, mode);
+}
+
+/**
+ *      swsusp_unmark - Unmark swsusp signature in the resume device
+ */
+
+#ifdef CONFIG_SUSPEND
+int swsusp_unmark(void)
+{
+	int error;
+
+	hib_submit_io(REQ_OP_READ, swsusp_resume_block,
+			swsusp_header, NULL);
+	if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) {
+		memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
+		error = hib_submit_io(REQ_OP_WRITE | REQ_SYNC,
+					swsusp_resume_block,
+					swsusp_header, NULL);
+	} else {
+		pr_err("Cannot find swsusp signature!\n");
+		error = -ENODEV;
+	}
+
+	/*
+	 * We just returned from suspend, we don't need the image any more.
+	 */
+	free_all_swap_pages(root_swap);
+
+	return error;
+}
+#endif
+
+static int __init swsusp_header_init(void)
+{
+	swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
+	if (!swsusp_header)
+		panic("Could not allocate memory for swsusp_header\n");
+	return 0;
+}
+
+core_initcall(swsusp_header_init);
diff --git a/kernel/power/user.c b/kernel/power/user.c
new file mode 100644
index 000000000..3a4e70366
--- /dev/null
+++ b/kernel/power/user.c
@@ -0,0 +1,466 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/kernel/power/user.c
+ *
+ * This file provides the user space interface for software suspend/resume.
+ *
+ * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
+ */
+
+#include <linux/suspend.h>
+#include <linux/reboot.h>
+#include <linux/string.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/pm.h>
+#include <linux/fs.h>
+#include <linux/compat.h>
+#include <linux/console.h>
+#include <linux/cpu.h>
+#include <linux/freezer.h>
+
+#include <linux/uaccess.h>
+
+#include "power.h"
+
+static bool need_wait;
+
+static struct snapshot_data {
+	struct snapshot_handle handle;
+	int swap;
+	int mode;
+	bool frozen;
+	bool ready;
+	bool platform_support;
+	bool free_bitmaps;
+	dev_t dev;
+} snapshot_state;
+
+int is_hibernate_resume_dev(dev_t dev)
+{
+	return hibernation_available() && snapshot_state.dev == dev;
+}
+
+static int snapshot_open(struct inode *inode, struct file *filp)
+{
+	struct snapshot_data *data;
+	unsigned int sleep_flags;
+	int error;
+
+	if (!hibernation_available())
+		return -EPERM;
+
+	sleep_flags = lock_system_sleep();
+
+	if (!hibernate_acquire()) {
+		error = -EBUSY;
+		goto Unlock;
+	}
+
+	if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
+		hibernate_release();
+		error = -ENOSYS;
+		goto Unlock;
+	}
+	nonseekable_open(inode, filp);
+	data = &snapshot_state;
+	filp->private_data = data;
+	memset(&data->handle, 0, sizeof(struct snapshot_handle));
+	if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
+		/* Hibernating.  The image device should be accessible. */
+		data->swap = swap_type_of(swsusp_resume_device, 0);
+		data->mode = O_RDONLY;
+		data->free_bitmaps = false;
+		error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION);
+	} else {
+		/*
+		 * Resuming.  We may need to wait for the image device to
+		 * appear.
+		 */
+		need_wait = true;
+
+		data->swap = -1;
+		data->mode = O_WRONLY;
+		error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE);
+		if (!error) {
+			error = create_basic_memory_bitmaps();
+			data->free_bitmaps = !error;
+		}
+	}
+	if (error)
+		hibernate_release();
+
+	data->frozen = false;
+	data->ready = false;
+	data->platform_support = false;
+	data->dev = 0;
+
+ Unlock:
+	unlock_system_sleep(sleep_flags);
+
+	return error;
+}
+
+static int snapshot_release(struct inode *inode, struct file *filp)
+{
+	struct snapshot_data *data;
+	unsigned int sleep_flags;
+
+	sleep_flags = lock_system_sleep();
+
+	swsusp_free();
+	data = filp->private_data;
+	data->dev = 0;
+	free_all_swap_pages(data->swap);
+	if (data->frozen) {
+		pm_restore_gfp_mask();
+		free_basic_memory_bitmaps();
+		thaw_processes();
+	} else if (data->free_bitmaps) {
+		free_basic_memory_bitmaps();
+	}
+	pm_notifier_call_chain(data->mode == O_RDONLY ?
+			PM_POST_HIBERNATION : PM_POST_RESTORE);
+	hibernate_release();
+
+	unlock_system_sleep(sleep_flags);
+
+	return 0;
+}
+
+static ssize_t snapshot_read(struct file *filp, char __user *buf,
+                             size_t count, loff_t *offp)
+{
+	loff_t pg_offp = *offp & ~PAGE_MASK;
+	struct snapshot_data *data;
+	unsigned int sleep_flags;
+	ssize_t res;
+
+	sleep_flags = lock_system_sleep();
+
+	data = filp->private_data;
+	if (!data->ready) {
+		res = -ENODATA;
+		goto Unlock;
+	}
+	if (!pg_offp) { /* on page boundary? */
+		res = snapshot_read_next(&data->handle);
+		if (res <= 0)
+			goto Unlock;
+	} else {
+		res = PAGE_SIZE - pg_offp;
+	}
+
+	res = simple_read_from_buffer(buf, count, &pg_offp,
+			data_of(data->handle), res);
+	if (res > 0)
+		*offp += res;
+
+ Unlock:
+	unlock_system_sleep(sleep_flags);
+
+	return res;
+}
+
+static ssize_t snapshot_write(struct file *filp, const char __user *buf,
+                              size_t count, loff_t *offp)
+{
+	loff_t pg_offp = *offp & ~PAGE_MASK;
+	struct snapshot_data *data;
+	unsigned long sleep_flags;
+	ssize_t res;
+
+	if (need_wait) {
+		wait_for_device_probe();
+		need_wait = false;
+	}
+
+	sleep_flags = lock_system_sleep();
+
+	data = filp->private_data;
+
+	if (!pg_offp) {
+		res = snapshot_write_next(&data->handle);
+		if (res <= 0)
+			goto unlock;
+	} else {
+		res = PAGE_SIZE;
+	}
+
+	if (!data_of(data->handle)) {
+		res = -EINVAL;
+		goto unlock;
+	}
+
+	res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
+			buf, count);
+	if (res > 0)
+		*offp += res;
+unlock:
+	unlock_system_sleep(sleep_flags);
+
+	return res;
+}
+
+struct compat_resume_swap_area {
+	compat_loff_t offset;
+	u32 dev;
+} __packed;
+
+static int snapshot_set_swap_area(struct snapshot_data *data,
+		void __user *argp)
+{
+	sector_t offset;
+	dev_t swdev;
+
+	if (swsusp_swap_in_use())
+		return -EPERM;
+
+	if (in_compat_syscall()) {
+		struct compat_resume_swap_area swap_area;
+
+		if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
+			return -EFAULT;
+		swdev = new_decode_dev(swap_area.dev);
+		offset = swap_area.offset;
+	} else {
+		struct resume_swap_area swap_area;
+
+		if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
+			return -EFAULT;
+		swdev = new_decode_dev(swap_area.dev);
+		offset = swap_area.offset;
+	}
+
+	/*
+	 * User space encodes device types as two-byte values,
+	 * so we need to recode them
+	 */
+	data->swap = swap_type_of(swdev, offset);
+	if (data->swap < 0)
+		return swdev ? -ENODEV : -EINVAL;
+	data->dev = swdev;
+	return 0;
+}
+
+static long snapshot_ioctl(struct file *filp, unsigned int cmd,
+							unsigned long arg)
+{
+	int error = 0;
+	struct snapshot_data *data;
+	loff_t size;
+	sector_t offset;
+
+	if (need_wait) {
+		wait_for_device_probe();
+		need_wait = false;
+	}
+
+	if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
+		return -ENOTTY;
+	if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
+		return -ENOTTY;
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (!mutex_trylock(&system_transition_mutex))
+		return -EBUSY;
+
+	lock_device_hotplug();
+	data = filp->private_data;
+
+	switch (cmd) {
+
+	case SNAPSHOT_FREEZE:
+		if (data->frozen)
+			break;
+
+		ksys_sync_helper();
+
+		error = freeze_processes();
+		if (error)
+			break;
+
+		error = create_basic_memory_bitmaps();
+		if (error)
+			thaw_processes();
+		else
+			data->frozen = true;
+
+		break;
+
+	case SNAPSHOT_UNFREEZE:
+		if (!data->frozen || data->ready)
+			break;
+		pm_restore_gfp_mask();
+		free_basic_memory_bitmaps();
+		data->free_bitmaps = false;
+		thaw_processes();
+		data->frozen = false;
+		break;
+
+	case SNAPSHOT_CREATE_IMAGE:
+		if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
+			error = -EPERM;
+			break;
+		}
+		pm_restore_gfp_mask();
+		error = hibernation_snapshot(data->platform_support);
+		if (!error) {
+			error = put_user(in_suspend, (int __user *)arg);
+			data->ready = !freezer_test_done && !error;
+			freezer_test_done = false;
+		}
+		break;
+
+	case SNAPSHOT_ATOMIC_RESTORE:
+		snapshot_write_finalize(&data->handle);
+		if (data->mode != O_WRONLY || !data->frozen ||
+		    !snapshot_image_loaded(&data->handle)) {
+			error = -EPERM;
+			break;
+		}
+		error = hibernation_restore(data->platform_support);
+		break;
+
+	case SNAPSHOT_FREE:
+		swsusp_free();
+		memset(&data->handle, 0, sizeof(struct snapshot_handle));
+		data->ready = false;
+		/*
+		 * It is necessary to thaw kernel threads here, because
+		 * SNAPSHOT_CREATE_IMAGE may be invoked directly after
+		 * SNAPSHOT_FREE.  In that case, if kernel threads were not
+		 * thawed, the preallocation of memory carried out by
+		 * hibernation_snapshot() might run into problems (i.e. it
+		 * might fail or even deadlock).
+		 */
+		thaw_kernel_threads();
+		break;
+
+	case SNAPSHOT_PREF_IMAGE_SIZE:
+		image_size = arg;
+		break;
+
+	case SNAPSHOT_GET_IMAGE_SIZE:
+		if (!data->ready) {
+			error = -ENODATA;
+			break;
+		}
+		size = snapshot_get_image_size();
+		size <<= PAGE_SHIFT;
+		error = put_user(size, (loff_t __user *)arg);
+		break;
+
+	case SNAPSHOT_AVAIL_SWAP_SIZE:
+		size = count_swap_pages(data->swap, 1);
+		size <<= PAGE_SHIFT;
+		error = put_user(size, (loff_t __user *)arg);
+		break;
+
+	case SNAPSHOT_ALLOC_SWAP_PAGE:
+		if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
+			error = -ENODEV;
+			break;
+		}
+		offset = alloc_swapdev_block(data->swap);
+		if (offset) {
+			offset <<= PAGE_SHIFT;
+			error = put_user(offset, (loff_t __user *)arg);
+		} else {
+			error = -ENOSPC;
+		}
+		break;
+
+	case SNAPSHOT_FREE_SWAP_PAGES:
+		if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
+			error = -ENODEV;
+			break;
+		}
+		free_all_swap_pages(data->swap);
+		break;
+
+	case SNAPSHOT_S2RAM:
+		if (!data->frozen) {
+			error = -EPERM;
+			break;
+		}
+		/*
+		 * Tasks are frozen and the notifiers have been called with
+		 * PM_HIBERNATION_PREPARE
+		 */
+		error = suspend_devices_and_enter(PM_SUSPEND_MEM);
+		data->ready = false;
+		break;
+
+	case SNAPSHOT_PLATFORM_SUPPORT:
+		data->platform_support = !!arg;
+		break;
+
+	case SNAPSHOT_POWER_OFF:
+		if (data->platform_support)
+			error = hibernation_platform_enter();
+		break;
+
+	case SNAPSHOT_SET_SWAP_AREA:
+		error = snapshot_set_swap_area(data, (void __user *)arg);
+		break;
+
+	default:
+		error = -ENOTTY;
+
+	}
+
+	unlock_device_hotplug();
+	mutex_unlock(&system_transition_mutex);
+
+	return error;
+}
+
+#ifdef CONFIG_COMPAT
+static long
+snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
+
+	switch (cmd) {
+	case SNAPSHOT_GET_IMAGE_SIZE:
+	case SNAPSHOT_AVAIL_SWAP_SIZE:
+	case SNAPSHOT_ALLOC_SWAP_PAGE:
+	case SNAPSHOT_CREATE_IMAGE:
+	case SNAPSHOT_SET_SWAP_AREA:
+		return snapshot_ioctl(file, cmd,
+				      (unsigned long) compat_ptr(arg));
+	default:
+		return snapshot_ioctl(file, cmd, arg);
+	}
+}
+#endif /* CONFIG_COMPAT */
+
+static const struct file_operations snapshot_fops = {
+	.open = snapshot_open,
+	.release = snapshot_release,
+	.read = snapshot_read,
+	.write = snapshot_write,
+	.llseek = no_llseek,
+	.unlocked_ioctl = snapshot_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = snapshot_compat_ioctl,
+#endif
+};
+
+static struct miscdevice snapshot_device = {
+	.minor = SNAPSHOT_MINOR,
+	.name = "snapshot",
+	.fops = &snapshot_fops,
+};
+
+static int __init snapshot_device_init(void)
+{
+	return misc_register(&snapshot_device);
+};
+
+device_initcall(snapshot_device_init);
diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c
new file mode 100644
index 000000000..52571dcad
--- /dev/null
+++ b/kernel/power/wakelock.c
@@ -0,0 +1,285 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kernel/power/wakelock.c
+ *
+ * User space wakeup sources support.
+ *
+ * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
+ *
+ * This code is based on the analogous interface allowing user space to
+ * manipulate wakelocks on Android.
+ */
+
+#include <linux/capability.h>
+#include <linux/ctype.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/hrtimer.h>
+#include <linux/list.h>
+#include <linux/rbtree.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#include "power.h"
+
+static DEFINE_MUTEX(wakelocks_lock);
+
+struct wakelock {
+	char			*name;
+	struct rb_node		node;
+	struct wakeup_source	*ws;
+#ifdef CONFIG_PM_WAKELOCKS_GC
+	struct list_head	lru;
+#endif
+};
+
+static struct rb_root wakelocks_tree = RB_ROOT;
+
+ssize_t pm_show_wakelocks(char *buf, bool show_active)
+{
+	struct rb_node *node;
+	struct wakelock *wl;
+	int len = 0;
+
+	mutex_lock(&wakelocks_lock);
+
+	for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
+		wl = rb_entry(node, struct wakelock, node);
+		if (wl->ws->active == show_active)
+			len += sysfs_emit_at(buf, len, "%s ", wl->name);
+	}
+
+	len += sysfs_emit_at(buf, len, "\n");
+
+	mutex_unlock(&wakelocks_lock);
+	return len;
+}
+
+#if CONFIG_PM_WAKELOCKS_LIMIT > 0
+static unsigned int number_of_wakelocks;
+
+static inline bool wakelocks_limit_exceeded(void)
+{
+	return number_of_wakelocks > CONFIG_PM_WAKELOCKS_LIMIT;
+}
+
+static inline void increment_wakelocks_number(void)
+{
+	number_of_wakelocks++;
+}
+
+static inline void decrement_wakelocks_number(void)
+{
+	number_of_wakelocks--;
+}
+#else /* CONFIG_PM_WAKELOCKS_LIMIT = 0 */
+static inline bool wakelocks_limit_exceeded(void) { return false; }
+static inline void increment_wakelocks_number(void) {}
+static inline void decrement_wakelocks_number(void) {}
+#endif /* CONFIG_PM_WAKELOCKS_LIMIT */
+
+#ifdef CONFIG_PM_WAKELOCKS_GC
+#define WL_GC_COUNT_MAX	100
+#define WL_GC_TIME_SEC	300
+
+static void __wakelocks_gc(struct work_struct *work);
+static LIST_HEAD(wakelocks_lru_list);
+static DECLARE_WORK(wakelock_work, __wakelocks_gc);
+static unsigned int wakelocks_gc_count;
+
+static inline void wakelocks_lru_add(struct wakelock *wl)
+{
+	list_add(&wl->lru, &wakelocks_lru_list);
+}
+
+static inline void wakelocks_lru_most_recent(struct wakelock *wl)
+{
+	list_move(&wl->lru, &wakelocks_lru_list);
+}
+
+static void __wakelocks_gc(struct work_struct *work)
+{
+	struct wakelock *wl, *aux;
+	ktime_t now;
+
+	mutex_lock(&wakelocks_lock);
+
+	now = ktime_get();
+	list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) {
+		u64 idle_time_ns;
+		bool active;
+
+		spin_lock_irq(&wl->ws->lock);
+		idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws->last_time));
+		active = wl->ws->active;
+		spin_unlock_irq(&wl->ws->lock);
+
+		if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
+			break;
+
+		if (!active) {
+			wakeup_source_unregister(wl->ws);
+			rb_erase(&wl->node, &wakelocks_tree);
+			list_del(&wl->lru);
+			kfree(wl->name);
+			kfree(wl);
+			decrement_wakelocks_number();
+		}
+	}
+	wakelocks_gc_count = 0;
+
+	mutex_unlock(&wakelocks_lock);
+}
+
+static void wakelocks_gc(void)
+{
+	if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)
+		return;
+
+	schedule_work(&wakelock_work);
+}
+#else /* !CONFIG_PM_WAKELOCKS_GC */
+static inline void wakelocks_lru_add(struct wakelock *wl) {}
+static inline void wakelocks_lru_most_recent(struct wakelock *wl) {}
+static inline void wakelocks_gc(void) {}
+#endif /* !CONFIG_PM_WAKELOCKS_GC */
+
+static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
+					    bool add_if_not_found)
+{
+	struct rb_node **node = &wakelocks_tree.rb_node;
+	struct rb_node *parent = *node;
+	struct wakelock *wl;
+
+	while (*node) {
+		int diff;
+
+		parent = *node;
+		wl = rb_entry(*node, struct wakelock, node);
+		diff = strncmp(name, wl->name, len);
+		if (diff == 0) {
+			if (wl->name[len])
+				diff = -1;
+			else
+				return wl;
+		}
+		if (diff < 0)
+			node = &(*node)->rb_left;
+		else
+			node = &(*node)->rb_right;
+	}
+	if (!add_if_not_found)
+		return ERR_PTR(-EINVAL);
+
+	if (wakelocks_limit_exceeded())
+		return ERR_PTR(-ENOSPC);
+
+	/* Not found, we have to add a new one. */
+	wl = kzalloc(sizeof(*wl), GFP_KERNEL);
+	if (!wl)
+		return ERR_PTR(-ENOMEM);
+
+	wl->name = kstrndup(name, len, GFP_KERNEL);
+	if (!wl->name) {
+		kfree(wl);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	wl->ws = wakeup_source_register(NULL, wl->name);
+	if (!wl->ws) {
+		kfree(wl->name);
+		kfree(wl);
+		return ERR_PTR(-ENOMEM);
+	}
+	wl->ws->last_time = ktime_get();
+
+	rb_link_node(&wl->node, parent, node);
+	rb_insert_color(&wl->node, &wakelocks_tree);
+	wakelocks_lru_add(wl);
+	increment_wakelocks_number();
+	return wl;
+}
+
+int pm_wake_lock(const char *buf)
+{
+	const char *str = buf;
+	struct wakelock *wl;
+	u64 timeout_ns = 0;
+	size_t len;
+	int ret = 0;
+
+	if (!capable(CAP_BLOCK_SUSPEND))
+		return -EPERM;
+
+	while (*str && !isspace(*str))
+		str++;
+
+	len = str - buf;
+	if (!len)
+		return -EINVAL;
+
+	if (*str && *str != '\n') {
+		/* Find out if there's a valid timeout string appended. */
+		ret = kstrtou64(skip_spaces(str), 10, &timeout_ns);
+		if (ret)
+			return -EINVAL;
+	}
+
+	mutex_lock(&wakelocks_lock);
+
+	wl = wakelock_lookup_add(buf, len, true);
+	if (IS_ERR(wl)) {
+		ret = PTR_ERR(wl);
+		goto out;
+	}
+	if (timeout_ns) {
+		u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;
+
+		do_div(timeout_ms, NSEC_PER_MSEC);
+		__pm_wakeup_event(wl->ws, timeout_ms);
+	} else {
+		__pm_stay_awake(wl->ws);
+	}
+
+	wakelocks_lru_most_recent(wl);
+
+ out:
+	mutex_unlock(&wakelocks_lock);
+	return ret;
+}
+
+int pm_wake_unlock(const char *buf)
+{
+	struct wakelock *wl;
+	size_t len;
+	int ret = 0;
+
+	if (!capable(CAP_BLOCK_SUSPEND))
+		return -EPERM;
+
+	len = strlen(buf);
+	if (!len)
+		return -EINVAL;
+
+	if (buf[len-1] == '\n')
+		len--;
+
+	if (!len)
+		return -EINVAL;
+
+	mutex_lock(&wakelocks_lock);
+
+	wl = wakelock_lookup_add(buf, len, false);
+	if (IS_ERR(wl)) {
+		ret = PTR_ERR(wl);
+		goto out;
+	}
+	__pm_relax(wl->ws);
+
+	wakelocks_lru_most_recent(wl);
+	wakelocks_gc();
+
+ out:
+	mutex_unlock(&wakelocks_lock);
+	return ret;
+}
diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile
new file mode 100644
index 000000000..f5b388e81
--- /dev/null
+++ b/kernel/printk/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-y	= printk.o
+obj-$(CONFIG_PRINTK)	+= printk_safe.o
+obj-$(CONFIG_A11Y_BRAILLE_CONSOLE)	+= braille.o
+obj-$(CONFIG_PRINTK_INDEX)	+= index.o
+
+obj-$(CONFIG_PRINTK)                 += printk_support.o
+printk_support-y	             := printk_ringbuffer.o
+printk_support-$(CONFIG_SYSCTL)	     += sysctl.o
diff --git a/kernel/printk/braille.c b/kernel/printk/braille.c
new file mode 100644
index 000000000..17a9591e5
--- /dev/null
+++ b/kernel/printk/braille.c
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/console.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+
+#include "console_cmdline.h"
+#include "braille.h"
+
+int _braille_console_setup(char **str, char **brl_options)
+{
+	size_t len;
+
+	len = str_has_prefix(*str, "brl,");
+	if (len) {
+		*brl_options = "";
+		*str += len;
+		return 0;
+	}
+
+	len = str_has_prefix(*str, "brl=");
+	if (len) {
+		*brl_options = *str + len;
+		*str = strchr(*brl_options, ',');
+		if (!*str) {
+			pr_err("need port name after brl=\n");
+			return -EINVAL;
+		}
+		*((*str)++) = 0;
+	}
+
+	return 0;
+}
+
+int
+_braille_register_console(struct console *console, struct console_cmdline *c)
+{
+	int rtn = 0;
+
+	if (c->brl_options) {
+		console->flags |= CON_BRL;
+		rtn = braille_register_console(console, c->index, c->options,
+					       c->brl_options);
+	}
+
+	return rtn;
+}
+
+int
+_braille_unregister_console(struct console *console)
+{
+	if (console->flags & CON_BRL)
+		return braille_unregister_console(console);
+
+	return 0;
+}
diff --git a/kernel/printk/braille.h b/kernel/printk/braille.h
new file mode 100644
index 000000000..123154f86
--- /dev/null
+++ b/kernel/printk/braille.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _PRINTK_BRAILLE_H
+#define _PRINTK_BRAILLE_H
+
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+
+static inline void
+braille_set_options(struct console_cmdline *c, char *brl_options)
+{
+	c->brl_options = brl_options;
+}
+
+/*
+ * Setup console according to braille options.
+ * Return -EINVAL on syntax error, 0 on success (or no braille option was
+ * actually given).
+ * Modifies str to point to the serial options
+ * Sets brl_options to the parsed braille options.
+ */
+int
+_braille_console_setup(char **str, char **brl_options);
+
+int
+_braille_register_console(struct console *console, struct console_cmdline *c);
+
+int
+_braille_unregister_console(struct console *console);
+
+#else
+
+static inline void
+braille_set_options(struct console_cmdline *c, char *brl_options)
+{
+}
+
+static inline int
+_braille_console_setup(char **str, char **brl_options)
+{
+	return 0;
+}
+
+static inline int
+_braille_register_console(struct console *console, struct console_cmdline *c)
+{
+	return 0;
+}
+
+static inline int
+_braille_unregister_console(struct console *console)
+{
+	return 0;
+}
+
+#endif
+
+#endif
diff --git a/kernel/printk/console_cmdline.h b/kernel/printk/console_cmdline.h
new file mode 100644
index 000000000..3ca74ad39
--- /dev/null
+++ b/kernel/printk/console_cmdline.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _CONSOLE_CMDLINE_H
+#define _CONSOLE_CMDLINE_H
+
+struct console_cmdline
+{
+	char	name[16];			/* Name of the driver	    */
+	int	index;				/* Minor dev. to use	    */
+	bool	user_specified;			/* Specified by command line vs. platform */
+	char	*options;			/* Options for the driver   */
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+	char	*brl_options;			/* Options for braille driver */
+#endif
+};
+
+#endif
diff --git a/kernel/printk/index.c b/kernel/printk/index.c
new file mode 100644
index 000000000..a6b27526b
--- /dev/null
+++ b/kernel/printk/index.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Userspace indexing of printk formats
+ */
+
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/string_helpers.h>
+
+#include "internal.h"
+
+extern struct pi_entry *__start_printk_index[];
+extern struct pi_entry *__stop_printk_index[];
+
+/* The base dir for module formats, typically debugfs/printk/index/ */
+static struct dentry *dfs_index;
+
+static struct pi_entry *pi_get_entry(const struct module *mod, loff_t pos)
+{
+	struct pi_entry **entries;
+	unsigned int nr_entries;
+
+#ifdef CONFIG_MODULES
+	if (mod) {
+		entries = mod->printk_index_start;
+		nr_entries = mod->printk_index_size;
+	} else
+#endif
+	{
+		/* vmlinux, comes from linker symbols */
+		entries = __start_printk_index;
+		nr_entries = __stop_printk_index - __start_printk_index;
+	}
+
+	if (pos >= nr_entries)
+		return NULL;
+
+	return entries[pos];
+}
+
+static void *pi_next(struct seq_file *s, void *v, loff_t *pos)
+{
+	const struct module *mod = s->file->f_inode->i_private;
+	struct pi_entry *entry = pi_get_entry(mod, *pos);
+
+	(*pos)++;
+
+	return entry;
+}
+
+static void *pi_start(struct seq_file *s, loff_t *pos)
+{
+	/*
+	 * Make show() print the header line. Do not update *pos because
+	 * pi_next() still has to return the entry at index 0 later.
+	 */
+	if (*pos == 0)
+		return SEQ_START_TOKEN;
+
+	return pi_next(s, NULL, pos);
+}
+
+/*
+ * We need both ESCAPE_ANY and explicit characters from ESCAPE_SPECIAL in @only
+ * because otherwise ESCAPE_NAP will cause double quotes and backslashes to be
+ * ignored for quoting.
+ */
+#define seq_escape_printf_format(s, src) \
+	seq_escape_str(s, src, ESCAPE_ANY | ESCAPE_NAP | ESCAPE_APPEND, "\"\\")
+
+static int pi_show(struct seq_file *s, void *v)
+{
+	const struct pi_entry *entry = v;
+	int level = LOGLEVEL_DEFAULT;
+	enum printk_info_flags flags = 0;
+	u16 prefix_len = 0;
+
+	if (v == SEQ_START_TOKEN) {
+		seq_puts(s, "# <level/flags> filename:line function \"format\"\n");
+		return 0;
+	}
+
+	if (!entry->fmt)
+		return 0;
+
+	if (entry->level)
+		printk_parse_prefix(entry->level, &level, &flags);
+	else
+		prefix_len = printk_parse_prefix(entry->fmt, &level, &flags);
+
+
+	if (flags & LOG_CONT) {
+		/*
+		 * LOGLEVEL_DEFAULT here means "use the same level as the
+		 * message we're continuing from", not the default message
+		 * loglevel, so don't display it as such.
+		 */
+		if (level == LOGLEVEL_DEFAULT)
+			seq_puts(s, "<c>");
+		else
+			seq_printf(s, "<%d,c>", level);
+	} else
+		seq_printf(s, "<%d>", level);
+
+	seq_printf(s, " %s:%d %s \"", entry->file, entry->line, entry->func);
+	if (entry->subsys_fmt_prefix)
+		seq_escape_printf_format(s, entry->subsys_fmt_prefix);
+	seq_escape_printf_format(s, entry->fmt + prefix_len);
+	seq_puts(s, "\"\n");
+
+	return 0;
+}
+
+static void pi_stop(struct seq_file *p, void *v) { }
+
+static const struct seq_operations dfs_index_sops = {
+	.start = pi_start,
+	.next  = pi_next,
+	.show  = pi_show,
+	.stop  = pi_stop,
+};
+
+DEFINE_SEQ_ATTRIBUTE(dfs_index);
+
+#ifdef CONFIG_MODULES
+static const char *pi_get_module_name(struct module *mod)
+{
+	return mod ? mod->name : "vmlinux";
+}
+#else
+static const char *pi_get_module_name(struct module *mod)
+{
+	return "vmlinux";
+}
+#endif
+
+static void pi_create_file(struct module *mod)
+{
+	debugfs_create_file(pi_get_module_name(mod), 0444, dfs_index,
+				       mod, &dfs_index_fops);
+}
+
+#ifdef CONFIG_MODULES
+static void pi_remove_file(struct module *mod)
+{
+	debugfs_lookup_and_remove(pi_get_module_name(mod), dfs_index);
+}
+
+static int pi_module_notify(struct notifier_block *nb, unsigned long op,
+			    void *data)
+{
+	struct module *mod = data;
+
+	switch (op) {
+	case MODULE_STATE_COMING:
+		pi_create_file(mod);
+		break;
+	case MODULE_STATE_GOING:
+		pi_remove_file(mod);
+		break;
+	default: /* we don't care about other module states */
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block module_printk_fmts_nb = {
+	.notifier_call = pi_module_notify,
+};
+
+static void __init pi_setup_module_notifier(void)
+{
+	register_module_notifier(&module_printk_fmts_nb);
+}
+#else
+static inline void __init pi_setup_module_notifier(void) { }
+#endif
+
+static int __init pi_init(void)
+{
+	struct dentry *dfs_root = debugfs_create_dir("printk", NULL);
+
+	dfs_index = debugfs_create_dir("index", dfs_root);
+	pi_setup_module_notifier();
+	pi_create_file(NULL);
+
+	return 0;
+}
+
+/* debugfs comes up on core and must be initialised first */
+postcore_initcall(pi_init);
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
new file mode 100644
index 000000000..d947ca6c8
--- /dev/null
+++ b/kernel/printk/internal.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * internal.h - printk internal definitions
+ */
+#include <linux/percpu.h>
+
+#if defined(CONFIG_PRINTK) && defined(CONFIG_SYSCTL)
+void __init printk_sysctl_init(void);
+int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write,
+			      void *buffer, size_t *lenp, loff_t *ppos);
+#else
+#define printk_sysctl_init() do { } while (0)
+#endif
+
+#ifdef CONFIG_PRINTK
+
+/* Flags for a single printk record. */
+enum printk_info_flags {
+	LOG_NEWLINE	= 2,	/* text ended with a newline */
+	LOG_CONT	= 8,	/* text is a fragment of a continuation line */
+};
+
+__printf(4, 0)
+int vprintk_store(int facility, int level,
+		  const struct dev_printk_info *dev_info,
+		  const char *fmt, va_list args);
+
+__printf(1, 0) int vprintk_default(const char *fmt, va_list args);
+__printf(1, 0) int vprintk_deferred(const char *fmt, va_list args);
+
+bool printk_percpu_data_ready(void);
+
+#define printk_safe_enter_irqsave(flags)	\
+	do {					\
+		local_irq_save(flags);		\
+		__printk_safe_enter();		\
+	} while (0)
+
+#define printk_safe_exit_irqrestore(flags)	\
+	do {					\
+		__printk_safe_exit();		\
+		local_irq_restore(flags);	\
+	} while (0)
+
+void defer_console_output(void);
+
+u16 printk_parse_prefix(const char *text, int *level,
+			enum printk_info_flags *flags);
+#else
+
+/*
+ * In !PRINTK builds we still export console_sem
+ * semaphore and some of console functions (console_unlock()/etc.), so
+ * printk-safe must preserve the existing local IRQ guarantees.
+ */
+#define printk_safe_enter_irqsave(flags) local_irq_save(flags)
+#define printk_safe_exit_irqrestore(flags) local_irq_restore(flags)
+
+static inline bool printk_percpu_data_ready(void) { return false; }
+#endif /* CONFIG_PRINTK */
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
new file mode 100644
index 000000000..cc53fb77f
--- /dev/null
+++ b/kernel/printk/printk.c
@@ -0,0 +1,3975 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/kernel/printk.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ * Modified to make sys_syslog() more flexible: added commands to
+ * return the last 4k of kernel messages, regardless of whether
+ * they've been read or not.  Added option to suppress kernel printk's
+ * to the console.  Added hook for sending the console messages
+ * elsewhere, in preparation for a serial line console (someday).
+ * Ted Ts'o, 2/11/93.
+ * Modified for sysctl support, 1/8/97, Chris Horn.
+ * Fixed SMP synchronization, 08/08/99, Manfred Spraul
+ *     manfred@colorfullife.com
+ * Rewrote bits to get rid of console_lock
+ *	01Mar01 Andrew Morton
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/console.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/nmi.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/delay.h>
+#include <linux/smp.h>
+#include <linux/security.h>
+#include <linux/memblock.h>
+#include <linux/syscalls.h>
+#include <linux/crash_core.h>
+#include <linux/ratelimit.h>
+#include <linux/kmsg_dump.h>
+#include <linux/syslog.h>
+#include <linux/cpu.h>
+#include <linux/rculist.h>
+#include <linux/poll.h>
+#include <linux/irq_work.h>
+#include <linux/ctype.h>
+#include <linux/uio.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/task_stack.h>
+
+#include <linux/uaccess.h>
+#include <asm/sections.h>
+
+#include <trace/events/initcall.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/printk.h>
+
+#include "printk_ringbuffer.h"
+#include "console_cmdline.h"
+#include "braille.h"
+#include "internal.h"
+
+int console_printk[4] = {
+	CONSOLE_LOGLEVEL_DEFAULT,	/* console_loglevel */
+	MESSAGE_LOGLEVEL_DEFAULT,	/* default_message_loglevel */
+	CONSOLE_LOGLEVEL_MIN,		/* minimum_console_loglevel */
+	CONSOLE_LOGLEVEL_DEFAULT,	/* default_console_loglevel */
+};
+EXPORT_SYMBOL_GPL(console_printk);
+
+atomic_t ignore_console_lock_warning __read_mostly = ATOMIC_INIT(0);
+EXPORT_SYMBOL(ignore_console_lock_warning);
+
+/*
+ * Low level drivers may need that to know if they can schedule in
+ * their unblank() callback or not. So let's export it.
+ */
+int oops_in_progress;
+EXPORT_SYMBOL(oops_in_progress);
+
+/*
+ * console_sem protects the console_drivers list, and also
+ * provides serialisation for access to the entire console
+ * driver system.
+ */
+static DEFINE_SEMAPHORE(console_sem);
+struct console *console_drivers;
+EXPORT_SYMBOL_GPL(console_drivers);
+
+/*
+ * System may need to suppress printk message under certain
+ * circumstances, like after kernel panic happens.
+ */
+int __read_mostly suppress_printk;
+
+/*
+ * During panic, heavy printk by other CPUs can delay the
+ * panic and risk deadlock on console resources.
+ */
+static int __read_mostly suppress_panic_printk;
+
+#ifdef CONFIG_LOCKDEP
+static struct lockdep_map console_lock_dep_map = {
+	.name = "console_lock"
+};
+#endif
+
+enum devkmsg_log_bits {
+	__DEVKMSG_LOG_BIT_ON = 0,
+	__DEVKMSG_LOG_BIT_OFF,
+	__DEVKMSG_LOG_BIT_LOCK,
+};
+
+enum devkmsg_log_masks {
+	DEVKMSG_LOG_MASK_ON             = BIT(__DEVKMSG_LOG_BIT_ON),
+	DEVKMSG_LOG_MASK_OFF            = BIT(__DEVKMSG_LOG_BIT_OFF),
+	DEVKMSG_LOG_MASK_LOCK           = BIT(__DEVKMSG_LOG_BIT_LOCK),
+};
+
+/* Keep both the 'on' and 'off' bits clear, i.e. ratelimit by default: */
+#define DEVKMSG_LOG_MASK_DEFAULT	0
+
+static unsigned int __read_mostly devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT;
+
+static int __control_devkmsg(char *str)
+{
+	size_t len;
+
+	if (!str)
+		return -EINVAL;
+
+	len = str_has_prefix(str, "on");
+	if (len) {
+		devkmsg_log = DEVKMSG_LOG_MASK_ON;
+		return len;
+	}
+
+	len = str_has_prefix(str, "off");
+	if (len) {
+		devkmsg_log = DEVKMSG_LOG_MASK_OFF;
+		return len;
+	}
+
+	len = str_has_prefix(str, "ratelimit");
+	if (len) {
+		devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT;
+		return len;
+	}
+
+	return -EINVAL;
+}
+
+static int __init control_devkmsg(char *str)
+{
+	if (__control_devkmsg(str) < 0) {
+		pr_warn("printk.devkmsg: bad option string '%s'\n", str);
+		return 1;
+	}
+
+	/*
+	 * Set sysctl string accordingly:
+	 */
+	if (devkmsg_log == DEVKMSG_LOG_MASK_ON)
+		strcpy(devkmsg_log_str, "on");
+	else if (devkmsg_log == DEVKMSG_LOG_MASK_OFF)
+		strcpy(devkmsg_log_str, "off");
+	/* else "ratelimit" which is set by default. */
+
+	/*
+	 * Sysctl cannot change it anymore. The kernel command line setting of
+	 * this parameter is to force the setting to be permanent throughout the
+	 * runtime of the system. This is a precation measure against userspace
+	 * trying to be a smarta** and attempting to change it up on us.
+	 */
+	devkmsg_log |= DEVKMSG_LOG_MASK_LOCK;
+
+	return 1;
+}
+__setup("printk.devkmsg=", control_devkmsg);
+
+char devkmsg_log_str[DEVKMSG_STR_MAX_SIZE] = "ratelimit";
+#if defined(CONFIG_PRINTK) && defined(CONFIG_SYSCTL)
+int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write,
+			      void *buffer, size_t *lenp, loff_t *ppos)
+{
+	char old_str[DEVKMSG_STR_MAX_SIZE];
+	unsigned int old;
+	int err;
+
+	if (write) {
+		if (devkmsg_log & DEVKMSG_LOG_MASK_LOCK)
+			return -EINVAL;
+
+		old = devkmsg_log;
+		strncpy(old_str, devkmsg_log_str, DEVKMSG_STR_MAX_SIZE);
+	}
+
+	err = proc_dostring(table, write, buffer, lenp, ppos);
+	if (err)
+		return err;
+
+	if (write) {
+		err = __control_devkmsg(devkmsg_log_str);
+
+		/*
+		 * Do not accept an unknown string OR a known string with
+		 * trailing crap...
+		 */
+		if (err < 0 || (err + 1 != *lenp)) {
+
+			/* ... and restore old setting. */
+			devkmsg_log = old;
+			strncpy(devkmsg_log_str, old_str, DEVKMSG_STR_MAX_SIZE);
+
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+#endif /* CONFIG_PRINTK && CONFIG_SYSCTL */
+
+/*
+ * Helper macros to handle lockdep when locking/unlocking console_sem. We use
+ * macros instead of functions so that _RET_IP_ contains useful information.
+ */
+#define down_console_sem() do { \
+	down(&console_sem);\
+	mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);\
+} while (0)
+
+static int __down_trylock_console_sem(unsigned long ip)
+{
+	int lock_failed;
+	unsigned long flags;
+
+	/*
+	 * Here and in __up_console_sem() we need to be in safe mode,
+	 * because spindump/WARN/etc from under console ->lock will
+	 * deadlock in printk()->down_trylock_console_sem() otherwise.
+	 */
+	printk_safe_enter_irqsave(flags);
+	lock_failed = down_trylock(&console_sem);
+	printk_safe_exit_irqrestore(flags);
+
+	if (lock_failed)
+		return 1;
+	mutex_acquire(&console_lock_dep_map, 0, 1, ip);
+	return 0;
+}
+#define down_trylock_console_sem() __down_trylock_console_sem(_RET_IP_)
+
+static void __up_console_sem(unsigned long ip)
+{
+	unsigned long flags;
+
+	mutex_release(&console_lock_dep_map, ip);
+
+	printk_safe_enter_irqsave(flags);
+	up(&console_sem);
+	printk_safe_exit_irqrestore(flags);
+}
+#define up_console_sem() __up_console_sem(_RET_IP_)
+
+static bool panic_in_progress(void)
+{
+	return unlikely(atomic_read(&panic_cpu) != PANIC_CPU_INVALID);
+}
+
+/*
+ * This is used for debugging the mess that is the VT code by
+ * keeping track if we have the console semaphore held. It's
+ * definitely not the perfect debug tool (we don't know if _WE_
+ * hold it and are racing, but it helps tracking those weird code
+ * paths in the console code where we end up in places I want
+ * locked without the console semaphore held).
+ */
+static int console_locked, console_suspended;
+
+/*
+ *	Array of consoles built from command line options (console=)
+ */
+
+#define MAX_CMDLINECONSOLES 8
+
+static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES];
+
+static int preferred_console = -1;
+int console_set_on_cmdline;
+EXPORT_SYMBOL(console_set_on_cmdline);
+
+/* Flag: console code may call schedule() */
+static int console_may_schedule;
+
+enum con_msg_format_flags {
+	MSG_FORMAT_DEFAULT	= 0,
+	MSG_FORMAT_SYSLOG	= (1 << 0),
+};
+
+static int console_msg_format = MSG_FORMAT_DEFAULT;
+
+/*
+ * The printk log buffer consists of a sequenced collection of records, each
+ * containing variable length message text. Every record also contains its
+ * own meta-data (@info).
+ *
+ * Every record meta-data carries the timestamp in microseconds, as well as
+ * the standard userspace syslog level and syslog facility. The usual kernel
+ * messages use LOG_KERN; userspace-injected messages always carry a matching
+ * syslog facility, by default LOG_USER. The origin of every message can be
+ * reliably determined that way.
+ *
+ * The human readable log message of a record is available in @text, the
+ * length of the message text in @text_len. The stored message is not
+ * terminated.
+ *
+ * Optionally, a record can carry a dictionary of properties (key/value
+ * pairs), to provide userspace with a machine-readable message context.
+ *
+ * Examples for well-defined, commonly used property names are:
+ *   DEVICE=b12:8               device identifier
+ *                                b12:8         block dev_t
+ *                                c127:3        char dev_t
+ *                                n8            netdev ifindex
+ *                                +sound:card0  subsystem:devname
+ *   SUBSYSTEM=pci              driver-core subsystem name
+ *
+ * Valid characters in property names are [a-zA-Z0-9.-_]. Property names
+ * and values are terminated by a '\0' character.
+ *
+ * Example of record values:
+ *   record.text_buf                = "it's a line" (unterminated)
+ *   record.info.seq                = 56
+ *   record.info.ts_nsec            = 36863
+ *   record.info.text_len           = 11
+ *   record.info.facility           = 0 (LOG_KERN)
+ *   record.info.flags              = 0
+ *   record.info.level              = 3 (LOG_ERR)
+ *   record.info.caller_id          = 299 (task 299)
+ *   record.info.dev_info.subsystem = "pci" (terminated)
+ *   record.info.dev_info.device    = "+pci:0000:00:01.0" (terminated)
+ *
+ * The 'struct printk_info' buffer must never be directly exported to
+ * userspace, it is a kernel-private implementation detail that might
+ * need to be changed in the future, when the requirements change.
+ *
+ * /dev/kmsg exports the structured data in the following line format:
+ *   "<level>,<sequnum>,<timestamp>,<contflag>[,additional_values, ... ];<message text>\n"
+ *
+ * Users of the export format should ignore possible additional values
+ * separated by ',', and find the message after the ';' character.
+ *
+ * The optional key/value pairs are attached as continuation lines starting
+ * with a space character and terminated by a newline. All possible
+ * non-prinatable characters are escaped in the "\xff" notation.
+ */
+
+/* syslog_lock protects syslog_* variables and write access to clear_seq. */
+static DEFINE_MUTEX(syslog_lock);
+
+#ifdef CONFIG_PRINTK
+DECLARE_WAIT_QUEUE_HEAD(log_wait);
+/* All 3 protected by @syslog_lock. */
+/* the next printk record to read by syslog(READ) or /proc/kmsg */
+static u64 syslog_seq;
+static size_t syslog_partial;
+static bool syslog_time;
+
+struct latched_seq {
+	seqcount_latch_t	latch;
+	u64			val[2];
+};
+
+/*
+ * The next printk record to read after the last 'clear' command. There are
+ * two copies (updated with seqcount_latch) so that reads can locklessly
+ * access a valid value. Writers are synchronized by @syslog_lock.
+ */
+static struct latched_seq clear_seq = {
+	.latch		= SEQCNT_LATCH_ZERO(clear_seq.latch),
+	.val[0]		= 0,
+	.val[1]		= 0,
+};
+
+#ifdef CONFIG_PRINTK_CALLER
+#define PREFIX_MAX		48
+#else
+#define PREFIX_MAX		32
+#endif
+
+/* the maximum size of a formatted record (i.e. with prefix added per line) */
+#define CONSOLE_LOG_MAX		1024
+
+/* the maximum size for a dropped text message */
+#define DROPPED_TEXT_MAX	64
+
+/* the maximum size allowed to be reserved for a record */
+#define LOG_LINE_MAX		(CONSOLE_LOG_MAX - PREFIX_MAX)
+
+#define LOG_LEVEL(v)		((v) & 0x07)
+#define LOG_FACILITY(v)		((v) >> 3 & 0xff)
+
+/* record buffer */
+#define LOG_ALIGN __alignof__(unsigned long)
+#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
+#define LOG_BUF_LEN_MAX (u32)(1 << 31)
+static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
+static char *log_buf = __log_buf;
+static u32 log_buf_len = __LOG_BUF_LEN;
+
+/*
+ * Define the average message size. This only affects the number of
+ * descriptors that will be available. Underestimating is better than
+ * overestimating (too many available descriptors is better than not enough).
+ */
+#define PRB_AVGBITS 5	/* 32 character average length */
+
+#if CONFIG_LOG_BUF_SHIFT <= PRB_AVGBITS
+#error CONFIG_LOG_BUF_SHIFT value too small.
+#endif
+_DEFINE_PRINTKRB(printk_rb_static, CONFIG_LOG_BUF_SHIFT - PRB_AVGBITS,
+		 PRB_AVGBITS, &__log_buf[0]);
+
+static struct printk_ringbuffer printk_rb_dynamic;
+
+static struct printk_ringbuffer *prb = &printk_rb_static;
+
+/*
+ * We cannot access per-CPU data (e.g. per-CPU flush irq_work) before
+ * per_cpu_areas are initialised. This variable is set to true when
+ * it's safe to access per-CPU data.
+ */
+static bool __printk_percpu_data_ready __ro_after_init;
+
+bool printk_percpu_data_ready(void)
+{
+	return __printk_percpu_data_ready;
+}
+
+/* Must be called under syslog_lock. */
+static void latched_seq_write(struct latched_seq *ls, u64 val)
+{
+	raw_write_seqcount_latch(&ls->latch);
+	ls->val[0] = val;
+	raw_write_seqcount_latch(&ls->latch);
+	ls->val[1] = val;
+}
+
+/* Can be called from any context. */
+static u64 latched_seq_read_nolock(struct latched_seq *ls)
+{
+	unsigned int seq;
+	unsigned int idx;
+	u64 val;
+
+	do {
+		seq = raw_read_seqcount_latch(&ls->latch);
+		idx = seq & 0x1;
+		val = ls->val[idx];
+	} while (read_seqcount_latch_retry(&ls->latch, seq));
+
+	return val;
+}
+
+/* Return log buffer address */
+char *log_buf_addr_get(void)
+{
+	return log_buf;
+}
+
+/* Return log buffer size */
+u32 log_buf_len_get(void)
+{
+	return log_buf_len;
+}
+
+/*
+ * Define how much of the log buffer we could take at maximum. The value
+ * must be greater than two. Note that only half of the buffer is available
+ * when the index points to the middle.
+ */
+#define MAX_LOG_TAKE_PART 4
+static const char trunc_msg[] = "<truncated>";
+
+static void truncate_msg(u16 *text_len, u16 *trunc_msg_len)
+{
+	/*
+	 * The message should not take the whole buffer. Otherwise, it might
+	 * get removed too soon.
+	 */
+	u32 max_text_len = log_buf_len / MAX_LOG_TAKE_PART;
+
+	if (*text_len > max_text_len)
+		*text_len = max_text_len;
+
+	/* enable the warning message (if there is room) */
+	*trunc_msg_len = strlen(trunc_msg);
+	if (*text_len >= *trunc_msg_len)
+		*text_len -= *trunc_msg_len;
+	else
+		*trunc_msg_len = 0;
+}
+
+int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT);
+
+static int syslog_action_restricted(int type)
+{
+	if (dmesg_restrict)
+		return 1;
+	/*
+	 * Unless restricted, we allow "read all" and "get buffer size"
+	 * for everybody.
+	 */
+	return type != SYSLOG_ACTION_READ_ALL &&
+	       type != SYSLOG_ACTION_SIZE_BUFFER;
+}
+
+static int check_syslog_permissions(int type, int source)
+{
+	/*
+	 * If this is from /proc/kmsg and we've already opened it, then we've
+	 * already done the capabilities checks at open time.
+	 */
+	if (source == SYSLOG_FROM_PROC && type != SYSLOG_ACTION_OPEN)
+		goto ok;
+
+	if (syslog_action_restricted(type)) {
+		if (capable(CAP_SYSLOG))
+			goto ok;
+		/*
+		 * For historical reasons, accept CAP_SYS_ADMIN too, with
+		 * a warning.
+		 */
+		if (capable(CAP_SYS_ADMIN)) {
+			pr_warn_once("%s (%d): Attempt to access syslog with "
+				     "CAP_SYS_ADMIN but no CAP_SYSLOG "
+				     "(deprecated).\n",
+				 current->comm, task_pid_nr(current));
+			goto ok;
+		}
+		return -EPERM;
+	}
+ok:
+	return security_syslog(type);
+}
+
+static void append_char(char **pp, char *e, char c)
+{
+	if (*pp < e)
+		*(*pp)++ = c;
+}
+
+static ssize_t info_print_ext_header(char *buf, size_t size,
+				     struct printk_info *info)
+{
+	u64 ts_usec = info->ts_nsec;
+	char caller[20];
+#ifdef CONFIG_PRINTK_CALLER
+	u32 id = info->caller_id;
+
+	snprintf(caller, sizeof(caller), ",caller=%c%u",
+		 id & 0x80000000 ? 'C' : 'T', id & ~0x80000000);
+#else
+	caller[0] = '\0';
+#endif
+
+	do_div(ts_usec, 1000);
+
+	return scnprintf(buf, size, "%u,%llu,%llu,%c%s;",
+			 (info->facility << 3) | info->level, info->seq,
+			 ts_usec, info->flags & LOG_CONT ? 'c' : '-', caller);
+}
+
+static ssize_t msg_add_ext_text(char *buf, size_t size,
+				const char *text, size_t text_len,
+				unsigned char endc)
+{
+	char *p = buf, *e = buf + size;
+	size_t i;
+
+	/* escape non-printable characters */
+	for (i = 0; i < text_len; i++) {
+		unsigned char c = text[i];
+
+		if (c < ' ' || c >= 127 || c == '\\')
+			p += scnprintf(p, e - p, "\\x%02x", c);
+		else
+			append_char(&p, e, c);
+	}
+	append_char(&p, e, endc);
+
+	return p - buf;
+}
+
+static ssize_t msg_add_dict_text(char *buf, size_t size,
+				 const char *key, const char *val)
+{
+	size_t val_len = strlen(val);
+	ssize_t len;
+
+	if (!val_len)
+		return 0;
+
+	len = msg_add_ext_text(buf, size, "", 0, ' ');	/* dict prefix */
+	len += msg_add_ext_text(buf + len, size - len, key, strlen(key), '=');
+	len += msg_add_ext_text(buf + len, size - len, val, val_len, '\n');
+
+	return len;
+}
+
+static ssize_t msg_print_ext_body(char *buf, size_t size,
+				  char *text, size_t text_len,
+				  struct dev_printk_info *dev_info)
+{
+	ssize_t len;
+
+	len = msg_add_ext_text(buf, size, text, text_len, '\n');
+
+	if (!dev_info)
+		goto out;
+
+	len += msg_add_dict_text(buf + len, size - len, "SUBSYSTEM",
+				 dev_info->subsystem);
+	len += msg_add_dict_text(buf + len, size - len, "DEVICE",
+				 dev_info->device);
+out:
+	return len;
+}
+
+/* /dev/kmsg - userspace message inject/listen interface */
+struct devkmsg_user {
+	atomic64_t seq;
+	struct ratelimit_state rs;
+	struct mutex lock;
+	char buf[CONSOLE_EXT_LOG_MAX];
+
+	struct printk_info info;
+	char text_buf[CONSOLE_EXT_LOG_MAX];
+	struct printk_record record;
+};
+
+static __printf(3, 4) __cold
+int devkmsg_emit(int facility, int level, const char *fmt, ...)
+{
+	va_list args;
+	int r;
+
+	va_start(args, fmt);
+	r = vprintk_emit(facility, level, NULL, fmt, args);
+	va_end(args);
+
+	return r;
+}
+
+static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from)
+{
+	char *buf, *line;
+	int level = default_message_loglevel;
+	int facility = 1;	/* LOG_USER */
+	struct file *file = iocb->ki_filp;
+	struct devkmsg_user *user = file->private_data;
+	size_t len = iov_iter_count(from);
+	ssize_t ret = len;
+
+	if (!user || len > LOG_LINE_MAX)
+		return -EINVAL;
+
+	/* Ignore when user logging is disabled. */
+	if (devkmsg_log & DEVKMSG_LOG_MASK_OFF)
+		return len;
+
+	/* Ratelimit when not explicitly enabled. */
+	if (!(devkmsg_log & DEVKMSG_LOG_MASK_ON)) {
+		if (!___ratelimit(&user->rs, current->comm))
+			return ret;
+	}
+
+	buf = kmalloc(len+1, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	buf[len] = '\0';
+	if (!copy_from_iter_full(buf, len, from)) {
+		kfree(buf);
+		return -EFAULT;
+	}
+
+	/*
+	 * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace
+	 * the decimal value represents 32bit, the lower 3 bit are the log
+	 * level, the rest are the log facility.
+	 *
+	 * If no prefix or no userspace facility is specified, we
+	 * enforce LOG_USER, to be able to reliably distinguish
+	 * kernel-generated messages from userspace-injected ones.
+	 */
+	line = buf;
+	if (line[0] == '<') {
+		char *endp = NULL;
+		unsigned int u;
+
+		u = simple_strtoul(line + 1, &endp, 10);
+		if (endp && endp[0] == '>') {
+			level = LOG_LEVEL(u);
+			if (LOG_FACILITY(u) != 0)
+				facility = LOG_FACILITY(u);
+			endp++;
+			line = endp;
+		}
+	}
+
+	devkmsg_emit(facility, level, "%s", line);
+	kfree(buf);
+	return ret;
+}
+
+static ssize_t devkmsg_read(struct file *file, char __user *buf,
+			    size_t count, loff_t *ppos)
+{
+	struct devkmsg_user *user = file->private_data;
+	struct printk_record *r = &user->record;
+	size_t len;
+	ssize_t ret;
+
+	if (!user)
+		return -EBADF;
+
+	ret = mutex_lock_interruptible(&user->lock);
+	if (ret)
+		return ret;
+
+	if (!prb_read_valid(prb, atomic64_read(&user->seq), r)) {
+		if (file->f_flags & O_NONBLOCK) {
+			ret = -EAGAIN;
+			goto out;
+		}
+
+		/*
+		 * Guarantee this task is visible on the waitqueue before
+		 * checking the wake condition.
+		 *
+		 * The full memory barrier within set_current_state() of
+		 * prepare_to_wait_event() pairs with the full memory barrier
+		 * within wq_has_sleeper().
+		 *
+		 * This pairs with __wake_up_klogd:A.
+		 */
+		ret = wait_event_interruptible(log_wait,
+				prb_read_valid(prb,
+					atomic64_read(&user->seq), r)); /* LMM(devkmsg_read:A) */
+		if (ret)
+			goto out;
+	}
+
+	if (r->info->seq != atomic64_read(&user->seq)) {
+		/* our last seen message is gone, return error and reset */
+		atomic64_set(&user->seq, r->info->seq);
+		ret = -EPIPE;
+		goto out;
+	}
+
+	len = info_print_ext_header(user->buf, sizeof(user->buf), r->info);
+	len += msg_print_ext_body(user->buf + len, sizeof(user->buf) - len,
+				  &r->text_buf[0], r->info->text_len,
+				  &r->info->dev_info);
+
+	atomic64_set(&user->seq, r->info->seq + 1);
+
+	if (len > count) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (copy_to_user(buf, user->buf, len)) {
+		ret = -EFAULT;
+		goto out;
+	}
+	ret = len;
+out:
+	mutex_unlock(&user->lock);
+	return ret;
+}
+
+/*
+ * Be careful when modifying this function!!!
+ *
+ * Only few operations are supported because the device works only with the
+ * entire variable length messages (records). Non-standard values are
+ * returned in the other cases and has been this way for quite some time.
+ * User space applications might depend on this behavior.
+ */
+static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct devkmsg_user *user = file->private_data;
+	loff_t ret = 0;
+
+	if (!user)
+		return -EBADF;
+	if (offset)
+		return -ESPIPE;
+
+	switch (whence) {
+	case SEEK_SET:
+		/* the first record */
+		atomic64_set(&user->seq, prb_first_valid_seq(prb));
+		break;
+	case SEEK_DATA:
+		/*
+		 * The first record after the last SYSLOG_ACTION_CLEAR,
+		 * like issued by 'dmesg -c'. Reading /dev/kmsg itself
+		 * changes no global state, and does not clear anything.
+		 */
+		atomic64_set(&user->seq, latched_seq_read_nolock(&clear_seq));
+		break;
+	case SEEK_END:
+		/* after the last record */
+		atomic64_set(&user->seq, prb_next_seq(prb));
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	return ret;
+}
+
+static __poll_t devkmsg_poll(struct file *file, poll_table *wait)
+{
+	struct devkmsg_user *user = file->private_data;
+	struct printk_info info;
+	__poll_t ret = 0;
+
+	if (!user)
+		return EPOLLERR|EPOLLNVAL;
+
+	poll_wait(file, &log_wait, wait);
+
+	if (prb_read_valid_info(prb, atomic64_read(&user->seq), &info, NULL)) {
+		/* return error when data has vanished underneath us */
+		if (info.seq != atomic64_read(&user->seq))
+			ret = EPOLLIN|EPOLLRDNORM|EPOLLERR|EPOLLPRI;
+		else
+			ret = EPOLLIN|EPOLLRDNORM;
+	}
+
+	return ret;
+}
+
+static int devkmsg_open(struct inode *inode, struct file *file)
+{
+	struct devkmsg_user *user;
+	int err;
+
+	if (devkmsg_log & DEVKMSG_LOG_MASK_OFF)
+		return -EPERM;
+
+	/* write-only does not need any file context */
+	if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
+		err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
+					       SYSLOG_FROM_READER);
+		if (err)
+			return err;
+	}
+
+	user = kvmalloc(sizeof(struct devkmsg_user), GFP_KERNEL);
+	if (!user)
+		return -ENOMEM;
+
+	ratelimit_default_init(&user->rs);
+	ratelimit_set_flags(&user->rs, RATELIMIT_MSG_ON_RELEASE);
+
+	mutex_init(&user->lock);
+
+	prb_rec_init_rd(&user->record, &user->info,
+			&user->text_buf[0], sizeof(user->text_buf));
+
+	atomic64_set(&user->seq, prb_first_valid_seq(prb));
+
+	file->private_data = user;
+	return 0;
+}
+
+static int devkmsg_release(struct inode *inode, struct file *file)
+{
+	struct devkmsg_user *user = file->private_data;
+
+	if (!user)
+		return 0;
+
+	ratelimit_state_exit(&user->rs);
+
+	mutex_destroy(&user->lock);
+	kvfree(user);
+	return 0;
+}
+
+const struct file_operations kmsg_fops = {
+	.open = devkmsg_open,
+	.read = devkmsg_read,
+	.write_iter = devkmsg_write,
+	.llseek = devkmsg_llseek,
+	.poll = devkmsg_poll,
+	.release = devkmsg_release,
+};
+
+#ifdef CONFIG_CRASH_CORE
+/*
+ * This appends the listed symbols to /proc/vmcore
+ *
+ * /proc/vmcore is used by various utilities, like crash and makedumpfile to
+ * obtain access to symbols that are otherwise very difficult to locate.  These
+ * symbols are specifically used so that utilities can access and extract the
+ * dmesg log from a vmcore file after a crash.
+ */
+void log_buf_vmcoreinfo_setup(void)
+{
+	struct dev_printk_info *dev_info = NULL;
+
+	VMCOREINFO_SYMBOL(prb);
+	VMCOREINFO_SYMBOL(printk_rb_static);
+	VMCOREINFO_SYMBOL(clear_seq);
+
+	/*
+	 * Export struct size and field offsets. User space tools can
+	 * parse it and detect any changes to structure down the line.
+	 */
+
+	VMCOREINFO_STRUCT_SIZE(printk_ringbuffer);
+	VMCOREINFO_OFFSET(printk_ringbuffer, desc_ring);
+	VMCOREINFO_OFFSET(printk_ringbuffer, text_data_ring);
+	VMCOREINFO_OFFSET(printk_ringbuffer, fail);
+
+	VMCOREINFO_STRUCT_SIZE(prb_desc_ring);
+	VMCOREINFO_OFFSET(prb_desc_ring, count_bits);
+	VMCOREINFO_OFFSET(prb_desc_ring, descs);
+	VMCOREINFO_OFFSET(prb_desc_ring, infos);
+	VMCOREINFO_OFFSET(prb_desc_ring, head_id);
+	VMCOREINFO_OFFSET(prb_desc_ring, tail_id);
+
+	VMCOREINFO_STRUCT_SIZE(prb_desc);
+	VMCOREINFO_OFFSET(prb_desc, state_var);
+	VMCOREINFO_OFFSET(prb_desc, text_blk_lpos);
+
+	VMCOREINFO_STRUCT_SIZE(prb_data_blk_lpos);
+	VMCOREINFO_OFFSET(prb_data_blk_lpos, begin);
+	VMCOREINFO_OFFSET(prb_data_blk_lpos, next);
+
+	VMCOREINFO_STRUCT_SIZE(printk_info);
+	VMCOREINFO_OFFSET(printk_info, seq);
+	VMCOREINFO_OFFSET(printk_info, ts_nsec);
+	VMCOREINFO_OFFSET(printk_info, text_len);
+	VMCOREINFO_OFFSET(printk_info, caller_id);
+	VMCOREINFO_OFFSET(printk_info, dev_info);
+
+	VMCOREINFO_STRUCT_SIZE(dev_printk_info);
+	VMCOREINFO_OFFSET(dev_printk_info, subsystem);
+	VMCOREINFO_LENGTH(printk_info_subsystem, sizeof(dev_info->subsystem));
+	VMCOREINFO_OFFSET(dev_printk_info, device);
+	VMCOREINFO_LENGTH(printk_info_device, sizeof(dev_info->device));
+
+	VMCOREINFO_STRUCT_SIZE(prb_data_ring);
+	VMCOREINFO_OFFSET(prb_data_ring, size_bits);
+	VMCOREINFO_OFFSET(prb_data_ring, data);
+	VMCOREINFO_OFFSET(prb_data_ring, head_lpos);
+	VMCOREINFO_OFFSET(prb_data_ring, tail_lpos);
+
+	VMCOREINFO_SIZE(atomic_long_t);
+	VMCOREINFO_TYPE_OFFSET(atomic_long_t, counter);
+
+	VMCOREINFO_STRUCT_SIZE(latched_seq);
+	VMCOREINFO_OFFSET(latched_seq, val);
+}
+#endif
+
+/* requested log_buf_len from kernel cmdline */
+static unsigned long __initdata new_log_buf_len;
+
+/* we practice scaling the ring buffer by powers of 2 */
+static void __init log_buf_len_update(u64 size)
+{
+	if (size > (u64)LOG_BUF_LEN_MAX) {
+		size = (u64)LOG_BUF_LEN_MAX;
+		pr_err("log_buf over 2G is not supported.\n");
+	}
+
+	if (size)
+		size = roundup_pow_of_two(size);
+	if (size > log_buf_len)
+		new_log_buf_len = (unsigned long)size;
+}
+
+/* save requested log_buf_len since it's too early to process it */
+static int __init log_buf_len_setup(char *str)
+{
+	u64 size;
+
+	if (!str)
+		return -EINVAL;
+
+	size = memparse(str, &str);
+
+	log_buf_len_update(size);
+
+	return 0;
+}
+early_param("log_buf_len", log_buf_len_setup);
+
+#ifdef CONFIG_SMP
+#define __LOG_CPU_MAX_BUF_LEN (1 << CONFIG_LOG_CPU_MAX_BUF_SHIFT)
+
+static void __init log_buf_add_cpu(void)
+{
+	unsigned int cpu_extra;
+
+	/*
+	 * archs should set up cpu_possible_bits properly with
+	 * set_cpu_possible() after setup_arch() but just in
+	 * case lets ensure this is valid.
+	 */
+	if (num_possible_cpus() == 1)
+		return;
+
+	cpu_extra = (num_possible_cpus() - 1) * __LOG_CPU_MAX_BUF_LEN;
+
+	/* by default this will only continue through for large > 64 CPUs */
+	if (cpu_extra <= __LOG_BUF_LEN / 2)
+		return;
+
+	pr_info("log_buf_len individual max cpu contribution: %d bytes\n",
+		__LOG_CPU_MAX_BUF_LEN);
+	pr_info("log_buf_len total cpu_extra contributions: %d bytes\n",
+		cpu_extra);
+	pr_info("log_buf_len min size: %d bytes\n", __LOG_BUF_LEN);
+
+	log_buf_len_update(cpu_extra + __LOG_BUF_LEN);
+}
+#else /* !CONFIG_SMP */
+static inline void log_buf_add_cpu(void) {}
+#endif /* CONFIG_SMP */
+
+static void __init set_percpu_data_ready(void)
+{
+	__printk_percpu_data_ready = true;
+}
+
+static unsigned int __init add_to_rb(struct printk_ringbuffer *rb,
+				     struct printk_record *r)
+{
+	struct prb_reserved_entry e;
+	struct printk_record dest_r;
+
+	prb_rec_init_wr(&dest_r, r->info->text_len);
+
+	if (!prb_reserve(&e, rb, &dest_r))
+		return 0;
+
+	memcpy(&dest_r.text_buf[0], &r->text_buf[0], r->info->text_len);
+	dest_r.info->text_len = r->info->text_len;
+	dest_r.info->facility = r->info->facility;
+	dest_r.info->level = r->info->level;
+	dest_r.info->flags = r->info->flags;
+	dest_r.info->ts_nsec = r->info->ts_nsec;
+	dest_r.info->caller_id = r->info->caller_id;
+	memcpy(&dest_r.info->dev_info, &r->info->dev_info, sizeof(dest_r.info->dev_info));
+
+	prb_final_commit(&e);
+
+	return prb_record_text_space(&e);
+}
+
+static char setup_text_buf[LOG_LINE_MAX] __initdata;
+
+void __init setup_log_buf(int early)
+{
+	struct printk_info *new_infos;
+	unsigned int new_descs_count;
+	struct prb_desc *new_descs;
+	struct printk_info info;
+	struct printk_record r;
+	unsigned int text_size;
+	size_t new_descs_size;
+	size_t new_infos_size;
+	unsigned long flags;
+	char *new_log_buf;
+	unsigned int free;
+	u64 seq;
+
+	/*
+	 * Some archs call setup_log_buf() multiple times - first is very
+	 * early, e.g. from setup_arch(), and second - when percpu_areas
+	 * are initialised.
+	 */
+	if (!early)
+		set_percpu_data_ready();
+
+	if (log_buf != __log_buf)
+		return;
+
+	if (!early && !new_log_buf_len)
+		log_buf_add_cpu();
+
+	if (!new_log_buf_len)
+		return;
+
+	new_descs_count = new_log_buf_len >> PRB_AVGBITS;
+	if (new_descs_count == 0) {
+		pr_err("new_log_buf_len: %lu too small\n", new_log_buf_len);
+		return;
+	}
+
+	new_log_buf = memblock_alloc(new_log_buf_len, LOG_ALIGN);
+	if (unlikely(!new_log_buf)) {
+		pr_err("log_buf_len: %lu text bytes not available\n",
+		       new_log_buf_len);
+		return;
+	}
+
+	new_descs_size = new_descs_count * sizeof(struct prb_desc);
+	new_descs = memblock_alloc(new_descs_size, LOG_ALIGN);
+	if (unlikely(!new_descs)) {
+		pr_err("log_buf_len: %zu desc bytes not available\n",
+		       new_descs_size);
+		goto err_free_log_buf;
+	}
+
+	new_infos_size = new_descs_count * sizeof(struct printk_info);
+	new_infos = memblock_alloc(new_infos_size, LOG_ALIGN);
+	if (unlikely(!new_infos)) {
+		pr_err("log_buf_len: %zu info bytes not available\n",
+		       new_infos_size);
+		goto err_free_descs;
+	}
+
+	prb_rec_init_rd(&r, &info, &setup_text_buf[0], sizeof(setup_text_buf));
+
+	prb_init(&printk_rb_dynamic,
+		 new_log_buf, ilog2(new_log_buf_len),
+		 new_descs, ilog2(new_descs_count),
+		 new_infos);
+
+	local_irq_save(flags);
+
+	log_buf_len = new_log_buf_len;
+	log_buf = new_log_buf;
+	new_log_buf_len = 0;
+
+	free = __LOG_BUF_LEN;
+	prb_for_each_record(0, &printk_rb_static, seq, &r) {
+		text_size = add_to_rb(&printk_rb_dynamic, &r);
+		if (text_size > free)
+			free = 0;
+		else
+			free -= text_size;
+	}
+
+	prb = &printk_rb_dynamic;
+
+	local_irq_restore(flags);
+
+	/*
+	 * Copy any remaining messages that might have appeared from
+	 * NMI context after copying but before switching to the
+	 * dynamic buffer.
+	 */
+	prb_for_each_record(seq, &printk_rb_static, seq, &r) {
+		text_size = add_to_rb(&printk_rb_dynamic, &r);
+		if (text_size > free)
+			free = 0;
+		else
+			free -= text_size;
+	}
+
+	if (seq != prb_next_seq(&printk_rb_static)) {
+		pr_err("dropped %llu messages\n",
+		       prb_next_seq(&printk_rb_static) - seq);
+	}
+
+	pr_info("log_buf_len: %u bytes\n", log_buf_len);
+	pr_info("early log buf free: %u(%u%%)\n",
+		free, (free * 100) / __LOG_BUF_LEN);
+	return;
+
+err_free_descs:
+	memblock_free(new_descs, new_descs_size);
+err_free_log_buf:
+	memblock_free(new_log_buf, new_log_buf_len);
+}
+
+static bool __read_mostly ignore_loglevel;
+
+static int __init ignore_loglevel_setup(char *str)
+{
+	ignore_loglevel = true;
+	pr_info("debug: ignoring loglevel setting.\n");
+
+	return 0;
+}
+
+early_param("ignore_loglevel", ignore_loglevel_setup);
+module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(ignore_loglevel,
+		 "ignore loglevel setting (prints all kernel messages to the console)");
+
+static bool suppress_message_printing(int level)
+{
+	return (level >= console_loglevel && !ignore_loglevel);
+}
+
+#ifdef CONFIG_BOOT_PRINTK_DELAY
+
+static int boot_delay; /* msecs delay after each printk during bootup */
+static unsigned long long loops_per_msec;	/* based on boot_delay */
+
+static int __init boot_delay_setup(char *str)
+{
+	unsigned long lpj;
+
+	lpj = preset_lpj ? preset_lpj : 1000000;	/* some guess */
+	loops_per_msec = (unsigned long long)lpj / 1000 * HZ;
+
+	get_option(&str, &boot_delay);
+	if (boot_delay > 10 * 1000)
+		boot_delay = 0;
+
+	pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, "
+		"HZ: %d, loops_per_msec: %llu\n",
+		boot_delay, preset_lpj, lpj, HZ, loops_per_msec);
+	return 0;
+}
+early_param("boot_delay", boot_delay_setup);
+
+static void boot_delay_msec(int level)
+{
+	unsigned long long k;
+	unsigned long timeout;
+
+	if ((boot_delay == 0 || system_state >= SYSTEM_RUNNING)
+		|| suppress_message_printing(level)) {
+		return;
+	}
+
+	k = (unsigned long long)loops_per_msec * boot_delay;
+
+	timeout = jiffies + msecs_to_jiffies(boot_delay);
+	while (k) {
+		k--;
+		cpu_relax();
+		/*
+		 * use (volatile) jiffies to prevent
+		 * compiler reduction; loop termination via jiffies
+		 * is secondary and may or may not happen.
+		 */
+		if (time_after(jiffies, timeout))
+			break;
+		touch_nmi_watchdog();
+	}
+}
+#else
+static inline void boot_delay_msec(int level)
+{
+}
+#endif
+
+static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME);
+module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
+
+static size_t print_syslog(unsigned int level, char *buf)
+{
+	return sprintf(buf, "<%u>", level);
+}
+
+static size_t print_time(u64 ts, char *buf)
+{
+	unsigned long rem_nsec = do_div(ts, 1000000000);
+
+	return sprintf(buf, "[%5lu.%06lu]",
+		       (unsigned long)ts, rem_nsec / 1000);
+}
+
+#ifdef CONFIG_PRINTK_CALLER
+static size_t print_caller(u32 id, char *buf)
+{
+	char caller[12];
+
+	snprintf(caller, sizeof(caller), "%c%u",
+		 id & 0x80000000 ? 'C' : 'T', id & ~0x80000000);
+	return sprintf(buf, "[%6s]", caller);
+}
+#else
+#define print_caller(id, buf) 0
+#endif
+
+static size_t info_print_prefix(const struct printk_info  *info, bool syslog,
+				bool time, char *buf)
+{
+	size_t len = 0;
+
+	if (syslog)
+		len = print_syslog((info->facility << 3) | info->level, buf);
+
+	if (time)
+		len += print_time(info->ts_nsec, buf + len);
+
+	len += print_caller(info->caller_id, buf + len);
+
+	if (IS_ENABLED(CONFIG_PRINTK_CALLER) || time) {
+		buf[len++] = ' ';
+		buf[len] = '\0';
+	}
+
+	return len;
+}
+
+/*
+ * Prepare the record for printing. The text is shifted within the given
+ * buffer to avoid a need for another one. The following operations are
+ * done:
+ *
+ *   - Add prefix for each line.
+ *   - Drop truncated lines that no longer fit into the buffer.
+ *   - Add the trailing newline that has been removed in vprintk_store().
+ *   - Add a string terminator.
+ *
+ * Since the produced string is always terminated, the maximum possible
+ * return value is @r->text_buf_size - 1;
+ *
+ * Return: The length of the updated/prepared text, including the added
+ * prefixes and the newline. The terminator is not counted. The dropped
+ * line(s) are not counted.
+ */
+static size_t record_print_text(struct printk_record *r, bool syslog,
+				bool time)
+{
+	size_t text_len = r->info->text_len;
+	size_t buf_size = r->text_buf_size;
+	char *text = r->text_buf;
+	char prefix[PREFIX_MAX];
+	bool truncated = false;
+	size_t prefix_len;
+	size_t line_len;
+	size_t len = 0;
+	char *next;
+
+	/*
+	 * If the message was truncated because the buffer was not large
+	 * enough, treat the available text as if it were the full text.
+	 */
+	if (text_len > buf_size)
+		text_len = buf_size;
+
+	prefix_len = info_print_prefix(r->info, syslog, time, prefix);
+
+	/*
+	 * @text_len: bytes of unprocessed text
+	 * @line_len: bytes of current line _without_ newline
+	 * @text:     pointer to beginning of current line
+	 * @len:      number of bytes prepared in r->text_buf
+	 */
+	for (;;) {
+		next = memchr(text, '\n', text_len);
+		if (next) {
+			line_len = next - text;
+		} else {
+			/* Drop truncated line(s). */
+			if (truncated)
+				break;
+			line_len = text_len;
+		}
+
+		/*
+		 * Truncate the text if there is not enough space to add the
+		 * prefix and a trailing newline and a terminator.
+		 */
+		if (len + prefix_len + text_len + 1 + 1 > buf_size) {
+			/* Drop even the current line if no space. */
+			if (len + prefix_len + line_len + 1 + 1 > buf_size)
+				break;
+
+			text_len = buf_size - len - prefix_len - 1 - 1;
+			truncated = true;
+		}
+
+		memmove(text + prefix_len, text, text_len);
+		memcpy(text, prefix, prefix_len);
+
+		/*
+		 * Increment the prepared length to include the text and
+		 * prefix that were just moved+copied. Also increment for the
+		 * newline at the end of this line. If this is the last line,
+		 * there is no newline, but it will be added immediately below.
+		 */
+		len += prefix_len + line_len + 1;
+		if (text_len == line_len) {
+			/*
+			 * This is the last line. Add the trailing newline
+			 * removed in vprintk_store().
+			 */
+			text[prefix_len + line_len] = '\n';
+			break;
+		}
+
+		/*
+		 * Advance beyond the added prefix and the related line with
+		 * its newline.
+		 */
+		text += prefix_len + line_len + 1;
+
+		/*
+		 * The remaining text has only decreased by the line with its
+		 * newline.
+		 *
+		 * Note that @text_len can become zero. It happens when @text
+		 * ended with a newline (either due to truncation or the
+		 * original string ending with "\n\n"). The loop is correctly
+		 * repeated and (if not truncated) an empty line with a prefix
+		 * will be prepared.
+		 */
+		text_len -= line_len + 1;
+	}
+
+	/*
+	 * If a buffer was provided, it will be terminated. Space for the
+	 * string terminator is guaranteed to be available. The terminator is
+	 * not counted in the return value.
+	 */
+	if (buf_size > 0)
+		r->text_buf[len] = 0;
+
+	return len;
+}
+
+static size_t get_record_print_text_size(struct printk_info *info,
+					 unsigned int line_count,
+					 bool syslog, bool time)
+{
+	char prefix[PREFIX_MAX];
+	size_t prefix_len;
+
+	prefix_len = info_print_prefix(info, syslog, time, prefix);
+
+	/*
+	 * Each line will be preceded with a prefix. The intermediate
+	 * newlines are already within the text, but a final trailing
+	 * newline will be added.
+	 */
+	return ((prefix_len * line_count) + info->text_len + 1);
+}
+
+/*
+ * Beginning with @start_seq, find the first record where it and all following
+ * records up to (but not including) @max_seq fit into @size.
+ *
+ * @max_seq is simply an upper bound and does not need to exist. If the caller
+ * does not require an upper bound, -1 can be used for @max_seq.
+ */
+static u64 find_first_fitting_seq(u64 start_seq, u64 max_seq, size_t size,
+				  bool syslog, bool time)
+{
+	struct printk_info info;
+	unsigned int line_count;
+	size_t len = 0;
+	u64 seq;
+
+	/* Determine the size of the records up to @max_seq. */
+	prb_for_each_info(start_seq, prb, seq, &info, &line_count) {
+		if (info.seq >= max_seq)
+			break;
+		len += get_record_print_text_size(&info, line_count, syslog, time);
+	}
+
+	/*
+	 * Adjust the upper bound for the next loop to avoid subtracting
+	 * lengths that were never added.
+	 */
+	if (seq < max_seq)
+		max_seq = seq;
+
+	/*
+	 * Move first record forward until length fits into the buffer. Ignore
+	 * newest messages that were not counted in the above cycle. Messages
+	 * might appear and get lost in the meantime. This is a best effort
+	 * that prevents an infinite loop that could occur with a retry.
+	 */
+	prb_for_each_info(start_seq, prb, seq, &info, &line_count) {
+		if (len <= size || info.seq >= max_seq)
+			break;
+		len -= get_record_print_text_size(&info, line_count, syslog, time);
+	}
+
+	return seq;
+}
+
+/* The caller is responsible for making sure @size is greater than 0. */
+static int syslog_print(char __user *buf, int size)
+{
+	struct printk_info info;
+	struct printk_record r;
+	char *text;
+	int len = 0;
+	u64 seq;
+
+	text = kmalloc(CONSOLE_LOG_MAX, GFP_KERNEL);
+	if (!text)
+		return -ENOMEM;
+
+	prb_rec_init_rd(&r, &info, text, CONSOLE_LOG_MAX);
+
+	mutex_lock(&syslog_lock);
+
+	/*
+	 * Wait for the @syslog_seq record to be available. @syslog_seq may
+	 * change while waiting.
+	 */
+	do {
+		seq = syslog_seq;
+
+		mutex_unlock(&syslog_lock);
+		/*
+		 * Guarantee this task is visible on the waitqueue before
+		 * checking the wake condition.
+		 *
+		 * The full memory barrier within set_current_state() of
+		 * prepare_to_wait_event() pairs with the full memory barrier
+		 * within wq_has_sleeper().
+		 *
+		 * This pairs with __wake_up_klogd:A.
+		 */
+		len = wait_event_interruptible(log_wait,
+				prb_read_valid(prb, seq, NULL)); /* LMM(syslog_print:A) */
+		mutex_lock(&syslog_lock);
+
+		if (len)
+			goto out;
+	} while (syslog_seq != seq);
+
+	/*
+	 * Copy records that fit into the buffer. The above cycle makes sure
+	 * that the first record is always available.
+	 */
+	do {
+		size_t n;
+		size_t skip;
+		int err;
+
+		if (!prb_read_valid(prb, syslog_seq, &r))
+			break;
+
+		if (r.info->seq != syslog_seq) {
+			/* message is gone, move to next valid one */
+			syslog_seq = r.info->seq;
+			syslog_partial = 0;
+		}
+
+		/*
+		 * To keep reading/counting partial line consistent,
+		 * use printk_time value as of the beginning of a line.
+		 */
+		if (!syslog_partial)
+			syslog_time = printk_time;
+
+		skip = syslog_partial;
+		n = record_print_text(&r, true, syslog_time);
+		if (n - syslog_partial <= size) {
+			/* message fits into buffer, move forward */
+			syslog_seq = r.info->seq + 1;
+			n -= syslog_partial;
+			syslog_partial = 0;
+		} else if (!len){
+			/* partial read(), remember position */
+			n = size;
+			syslog_partial += n;
+		} else
+			n = 0;
+
+		if (!n)
+			break;
+
+		mutex_unlock(&syslog_lock);
+		err = copy_to_user(buf, text + skip, n);
+		mutex_lock(&syslog_lock);
+
+		if (err) {
+			if (!len)
+				len = -EFAULT;
+			break;
+		}
+
+		len += n;
+		size -= n;
+		buf += n;
+	} while (size);
+out:
+	mutex_unlock(&syslog_lock);
+	kfree(text);
+	return len;
+}
+
+static int syslog_print_all(char __user *buf, int size, bool clear)
+{
+	struct printk_info info;
+	struct printk_record r;
+	char *text;
+	int len = 0;
+	u64 seq;
+	bool time;
+
+	text = kmalloc(CONSOLE_LOG_MAX, GFP_KERNEL);
+	if (!text)
+		return -ENOMEM;
+
+	time = printk_time;
+	/*
+	 * Find first record that fits, including all following records,
+	 * into the user-provided buffer for this dump.
+	 */
+	seq = find_first_fitting_seq(latched_seq_read_nolock(&clear_seq), -1,
+				     size, true, time);
+
+	prb_rec_init_rd(&r, &info, text, CONSOLE_LOG_MAX);
+
+	len = 0;
+	prb_for_each_record(seq, prb, seq, &r) {
+		int textlen;
+
+		textlen = record_print_text(&r, true, time);
+
+		if (len + textlen > size) {
+			seq--;
+			break;
+		}
+
+		if (copy_to_user(buf + len, text, textlen))
+			len = -EFAULT;
+		else
+			len += textlen;
+
+		if (len < 0)
+			break;
+	}
+
+	if (clear) {
+		mutex_lock(&syslog_lock);
+		latched_seq_write(&clear_seq, seq);
+		mutex_unlock(&syslog_lock);
+	}
+
+	kfree(text);
+	return len;
+}
+
+static void syslog_clear(void)
+{
+	mutex_lock(&syslog_lock);
+	latched_seq_write(&clear_seq, prb_next_seq(prb));
+	mutex_unlock(&syslog_lock);
+}
+
+int do_syslog(int type, char __user *buf, int len, int source)
+{
+	struct printk_info info;
+	bool clear = false;
+	static int saved_console_loglevel = LOGLEVEL_DEFAULT;
+	int error;
+
+	error = check_syslog_permissions(type, source);
+	if (error)
+		return error;
+
+	switch (type) {
+	case SYSLOG_ACTION_CLOSE:	/* Close log */
+		break;
+	case SYSLOG_ACTION_OPEN:	/* Open log */
+		break;
+	case SYSLOG_ACTION_READ:	/* Read from log */
+		if (!buf || len < 0)
+			return -EINVAL;
+		if (!len)
+			return 0;
+		if (!access_ok(buf, len))
+			return -EFAULT;
+		error = syslog_print(buf, len);
+		break;
+	/* Read/clear last kernel messages */
+	case SYSLOG_ACTION_READ_CLEAR:
+		clear = true;
+		fallthrough;
+	/* Read last kernel messages */
+	case SYSLOG_ACTION_READ_ALL:
+		if (!buf || len < 0)
+			return -EINVAL;
+		if (!len)
+			return 0;
+		if (!access_ok(buf, len))
+			return -EFAULT;
+		error = syslog_print_all(buf, len, clear);
+		break;
+	/* Clear ring buffer */
+	case SYSLOG_ACTION_CLEAR:
+		syslog_clear();
+		break;
+	/* Disable logging to console */
+	case SYSLOG_ACTION_CONSOLE_OFF:
+		if (saved_console_loglevel == LOGLEVEL_DEFAULT)
+			saved_console_loglevel = console_loglevel;
+		console_loglevel = minimum_console_loglevel;
+		break;
+	/* Enable logging to console */
+	case SYSLOG_ACTION_CONSOLE_ON:
+		if (saved_console_loglevel != LOGLEVEL_DEFAULT) {
+			console_loglevel = saved_console_loglevel;
+			saved_console_loglevel = LOGLEVEL_DEFAULT;
+		}
+		break;
+	/* Set level of messages printed to console */
+	case SYSLOG_ACTION_CONSOLE_LEVEL:
+		if (len < 1 || len > 8)
+			return -EINVAL;
+		if (len < minimum_console_loglevel)
+			len = minimum_console_loglevel;
+		console_loglevel = len;
+		/* Implicitly re-enable logging to console */
+		saved_console_loglevel = LOGLEVEL_DEFAULT;
+		break;
+	/* Number of chars in the log buffer */
+	case SYSLOG_ACTION_SIZE_UNREAD:
+		mutex_lock(&syslog_lock);
+		if (!prb_read_valid_info(prb, syslog_seq, &info, NULL)) {
+			/* No unread messages. */
+			mutex_unlock(&syslog_lock);
+			return 0;
+		}
+		if (info.seq != syslog_seq) {
+			/* messages are gone, move to first one */
+			syslog_seq = info.seq;
+			syslog_partial = 0;
+		}
+		if (source == SYSLOG_FROM_PROC) {
+			/*
+			 * Short-cut for poll(/"proc/kmsg") which simply checks
+			 * for pending data, not the size; return the count of
+			 * records, not the length.
+			 */
+			error = prb_next_seq(prb) - syslog_seq;
+		} else {
+			bool time = syslog_partial ? syslog_time : printk_time;
+			unsigned int line_count;
+			u64 seq;
+
+			prb_for_each_info(syslog_seq, prb, seq, &info,
+					  &line_count) {
+				error += get_record_print_text_size(&info, line_count,
+								    true, time);
+				time = printk_time;
+			}
+			error -= syslog_partial;
+		}
+		mutex_unlock(&syslog_lock);
+		break;
+	/* Size of the log buffer */
+	case SYSLOG_ACTION_SIZE_BUFFER:
+		error = log_buf_len;
+		break;
+	default:
+		error = -EINVAL;
+		break;
+	}
+
+	return error;
+}
+
+SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
+{
+	return do_syslog(type, buf, len, SYSLOG_FROM_READER);
+}
+
+/*
+ * Special console_lock variants that help to reduce the risk of soft-lockups.
+ * They allow to pass console_lock to another printk() call using a busy wait.
+ */
+
+#ifdef CONFIG_LOCKDEP
+static struct lockdep_map console_owner_dep_map = {
+	.name = "console_owner"
+};
+#endif
+
+static DEFINE_RAW_SPINLOCK(console_owner_lock);
+static struct task_struct *console_owner;
+static bool console_waiter;
+
+/**
+ * console_lock_spinning_enable - mark beginning of code where another
+ *	thread might safely busy wait
+ *
+ * This basically converts console_lock into a spinlock. This marks
+ * the section where the console_lock owner can not sleep, because
+ * there may be a waiter spinning (like a spinlock). Also it must be
+ * ready to hand over the lock at the end of the section.
+ */
+static void console_lock_spinning_enable(void)
+{
+	raw_spin_lock(&console_owner_lock);
+	console_owner = current;
+	raw_spin_unlock(&console_owner_lock);
+
+	/* The waiter may spin on us after setting console_owner */
+	spin_acquire(&console_owner_dep_map, 0, 0, _THIS_IP_);
+}
+
+/**
+ * console_lock_spinning_disable_and_check - mark end of code where another
+ *	thread was able to busy wait and check if there is a waiter
+ *
+ * This is called at the end of the section where spinning is allowed.
+ * It has two functions. First, it is a signal that it is no longer
+ * safe to start busy waiting for the lock. Second, it checks if
+ * there is a busy waiter and passes the lock rights to her.
+ *
+ * Important: Callers lose the lock if there was a busy waiter.
+ *	They must not touch items synchronized by console_lock
+ *	in this case.
+ *
+ * Return: 1 if the lock rights were passed, 0 otherwise.
+ */
+static int console_lock_spinning_disable_and_check(void)
+{
+	int waiter;
+
+	raw_spin_lock(&console_owner_lock);
+	waiter = READ_ONCE(console_waiter);
+	console_owner = NULL;
+	raw_spin_unlock(&console_owner_lock);
+
+	if (!waiter) {
+		spin_release(&console_owner_dep_map, _THIS_IP_);
+		return 0;
+	}
+
+	/* The waiter is now free to continue */
+	WRITE_ONCE(console_waiter, false);
+
+	spin_release(&console_owner_dep_map, _THIS_IP_);
+
+	/*
+	 * Hand off console_lock to waiter. The waiter will perform
+	 * the up(). After this, the waiter is the console_lock owner.
+	 */
+	mutex_release(&console_lock_dep_map, _THIS_IP_);
+	return 1;
+}
+
+/**
+ * console_trylock_spinning - try to get console_lock by busy waiting
+ *
+ * This allows to busy wait for the console_lock when the current
+ * owner is running in specially marked sections. It means that
+ * the current owner is running and cannot reschedule until it
+ * is ready to lose the lock.
+ *
+ * Return: 1 if we got the lock, 0 othrewise
+ */
+static int console_trylock_spinning(void)
+{
+	struct task_struct *owner = NULL;
+	bool waiter;
+	bool spin = false;
+	unsigned long flags;
+
+	if (console_trylock())
+		return 1;
+
+	/*
+	 * It's unsafe to spin once a panic has begun. If we are the
+	 * panic CPU, we may have already halted the owner of the
+	 * console_sem. If we are not the panic CPU, then we should
+	 * avoid taking console_sem, so the panic CPU has a better
+	 * chance of cleanly acquiring it later.
+	 */
+	if (panic_in_progress())
+		return 0;
+
+	printk_safe_enter_irqsave(flags);
+
+	raw_spin_lock(&console_owner_lock);
+	owner = READ_ONCE(console_owner);
+	waiter = READ_ONCE(console_waiter);
+	if (!waiter && owner && owner != current) {
+		WRITE_ONCE(console_waiter, true);
+		spin = true;
+	}
+	raw_spin_unlock(&console_owner_lock);
+
+	/*
+	 * If there is an active printk() writing to the
+	 * consoles, instead of having it write our data too,
+	 * see if we can offload that load from the active
+	 * printer, and do some printing ourselves.
+	 * Go into a spin only if there isn't already a waiter
+	 * spinning, and there is an active printer, and
+	 * that active printer isn't us (recursive printk?).
+	 */
+	if (!spin) {
+		printk_safe_exit_irqrestore(flags);
+		return 0;
+	}
+
+	/* We spin waiting for the owner to release us */
+	spin_acquire(&console_owner_dep_map, 0, 0, _THIS_IP_);
+	/* Owner will clear console_waiter on hand off */
+	while (READ_ONCE(console_waiter))
+		cpu_relax();
+	spin_release(&console_owner_dep_map, _THIS_IP_);
+
+	printk_safe_exit_irqrestore(flags);
+	/*
+	 * The owner passed the console lock to us.
+	 * Since we did not spin on console lock, annotate
+	 * this as a trylock. Otherwise lockdep will
+	 * complain.
+	 */
+	mutex_acquire(&console_lock_dep_map, 0, 1, _THIS_IP_);
+
+	return 1;
+}
+
+/*
+ * Call the specified console driver, asking it to write out the specified
+ * text and length. If @dropped_text is non-NULL and any records have been
+ * dropped, a dropped message will be written out first.
+ */
+static void call_console_driver(struct console *con, const char *text, size_t len,
+				char *dropped_text)
+{
+	size_t dropped_len;
+
+	if (con->dropped && dropped_text) {
+		dropped_len = snprintf(dropped_text, DROPPED_TEXT_MAX,
+				       "** %lu printk messages dropped **\n",
+				       con->dropped);
+		con->dropped = 0;
+		con->write(con, dropped_text, dropped_len);
+	}
+
+	con->write(con, text, len);
+}
+
+/*
+ * Recursion is tracked separately on each CPU. If NMIs are supported, an
+ * additional NMI context per CPU is also separately tracked. Until per-CPU
+ * is available, a separate "early tracking" is performed.
+ */
+static DEFINE_PER_CPU(u8, printk_count);
+static u8 printk_count_early;
+#ifdef CONFIG_HAVE_NMI
+static DEFINE_PER_CPU(u8, printk_count_nmi);
+static u8 printk_count_nmi_early;
+#endif
+
+/*
+ * Recursion is limited to keep the output sane. printk() should not require
+ * more than 1 level of recursion (allowing, for example, printk() to trigger
+ * a WARN), but a higher value is used in case some printk-internal errors
+ * exist, such as the ringbuffer validation checks failing.
+ */
+#define PRINTK_MAX_RECURSION 3
+
+/*
+ * Return a pointer to the dedicated counter for the CPU+context of the
+ * caller.
+ */
+static u8 *__printk_recursion_counter(void)
+{
+#ifdef CONFIG_HAVE_NMI
+	if (in_nmi()) {
+		if (printk_percpu_data_ready())
+			return this_cpu_ptr(&printk_count_nmi);
+		return &printk_count_nmi_early;
+	}
+#endif
+	if (printk_percpu_data_ready())
+		return this_cpu_ptr(&printk_count);
+	return &printk_count_early;
+}
+
+/*
+ * Enter recursion tracking. Interrupts are disabled to simplify tracking.
+ * The caller must check the boolean return value to see if the recursion is
+ * allowed. On failure, interrupts are not disabled.
+ *
+ * @recursion_ptr must be a variable of type (u8 *) and is the same variable
+ * that is passed to printk_exit_irqrestore().
+ */
+#define printk_enter_irqsave(recursion_ptr, flags)	\
+({							\
+	bool success = true;				\
+							\
+	typecheck(u8 *, recursion_ptr);			\
+	local_irq_save(flags);				\
+	(recursion_ptr) = __printk_recursion_counter();	\
+	if (*(recursion_ptr) > PRINTK_MAX_RECURSION) {	\
+		local_irq_restore(flags);		\
+		success = false;			\
+	} else {					\
+		(*(recursion_ptr))++;			\
+	}						\
+	success;					\
+})
+
+/* Exit recursion tracking, restoring interrupts. */
+#define printk_exit_irqrestore(recursion_ptr, flags)	\
+	do {						\
+		typecheck(u8 *, recursion_ptr);		\
+		(*(recursion_ptr))--;			\
+		local_irq_restore(flags);		\
+	} while (0)
+
+int printk_delay_msec __read_mostly;
+
+static inline void printk_delay(int level)
+{
+	boot_delay_msec(level);
+
+	if (unlikely(printk_delay_msec)) {
+		int m = printk_delay_msec;
+
+		while (m--) {
+			mdelay(1);
+			touch_nmi_watchdog();
+		}
+	}
+}
+
+static inline u32 printk_caller_id(void)
+{
+	return in_task() ? task_pid_nr(current) :
+		0x80000000 + smp_processor_id();
+}
+
+/**
+ * printk_parse_prefix - Parse level and control flags.
+ *
+ * @text:     The terminated text message.
+ * @level:    A pointer to the current level value, will be updated.
+ * @flags:    A pointer to the current printk_info flags, will be updated.
+ *
+ * @level may be NULL if the caller is not interested in the parsed value.
+ * Otherwise the variable pointed to by @level must be set to
+ * LOGLEVEL_DEFAULT in order to be updated with the parsed value.
+ *
+ * @flags may be NULL if the caller is not interested in the parsed value.
+ * Otherwise the variable pointed to by @flags will be OR'd with the parsed
+ * value.
+ *
+ * Return: The length of the parsed level and control flags.
+ */
+u16 printk_parse_prefix(const char *text, int *level,
+			enum printk_info_flags *flags)
+{
+	u16 prefix_len = 0;
+	int kern_level;
+
+	while (*text) {
+		kern_level = printk_get_level(text);
+		if (!kern_level)
+			break;
+
+		switch (kern_level) {
+		case '0' ... '7':
+			if (level && *level == LOGLEVEL_DEFAULT)
+				*level = kern_level - '0';
+			break;
+		case 'c':	/* KERN_CONT */
+			if (flags)
+				*flags |= LOG_CONT;
+		}
+
+		prefix_len += 2;
+		text += 2;
+	}
+
+	return prefix_len;
+}
+
+__printf(5, 0)
+static u16 printk_sprint(char *text, u16 size, int facility,
+			 enum printk_info_flags *flags, const char *fmt,
+			 va_list args)
+{
+	u16 text_len;
+
+	text_len = vscnprintf(text, size, fmt, args);
+
+	/* Mark and strip a trailing newline. */
+	if (text_len && text[text_len - 1] == '\n') {
+		text_len--;
+		*flags |= LOG_NEWLINE;
+	}
+
+	/* Strip log level and control flags. */
+	if (facility == 0) {
+		u16 prefix_len;
+
+		prefix_len = printk_parse_prefix(text, NULL, NULL);
+		if (prefix_len) {
+			text_len -= prefix_len;
+			memmove(text, text + prefix_len, text_len);
+		}
+	}
+
+	trace_console_rcuidle(text, text_len);
+
+	return text_len;
+}
+
+__printf(4, 0)
+int vprintk_store(int facility, int level,
+		  const struct dev_printk_info *dev_info,
+		  const char *fmt, va_list args)
+{
+	struct prb_reserved_entry e;
+	enum printk_info_flags flags = 0;
+	struct printk_record r;
+	unsigned long irqflags;
+	u16 trunc_msg_len = 0;
+	char prefix_buf[8];
+	u8 *recursion_ptr;
+	u16 reserve_size;
+	va_list args2;
+	u32 caller_id;
+	u16 text_len;
+	int ret = 0;
+	u64 ts_nsec;
+
+	if (!printk_enter_irqsave(recursion_ptr, irqflags))
+		return 0;
+
+	/*
+	 * Since the duration of printk() can vary depending on the message
+	 * and state of the ringbuffer, grab the timestamp now so that it is
+	 * close to the call of printk(). This provides a more deterministic
+	 * timestamp with respect to the caller.
+	 */
+	ts_nsec = local_clock();
+
+	caller_id = printk_caller_id();
+
+	/*
+	 * The sprintf needs to come first since the syslog prefix might be
+	 * passed in as a parameter. An extra byte must be reserved so that
+	 * later the vscnprintf() into the reserved buffer has room for the
+	 * terminating '\0', which is not counted by vsnprintf().
+	 */
+	va_copy(args2, args);
+	reserve_size = vsnprintf(&prefix_buf[0], sizeof(prefix_buf), fmt, args2) + 1;
+	va_end(args2);
+
+	if (reserve_size > LOG_LINE_MAX)
+		reserve_size = LOG_LINE_MAX;
+
+	/* Extract log level or control flags. */
+	if (facility == 0)
+		printk_parse_prefix(&prefix_buf[0], &level, &flags);
+
+	if (level == LOGLEVEL_DEFAULT)
+		level = default_message_loglevel;
+
+	if (dev_info)
+		flags |= LOG_NEWLINE;
+
+	if (flags & LOG_CONT) {
+		prb_rec_init_wr(&r, reserve_size);
+		if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) {
+			text_len = printk_sprint(&r.text_buf[r.info->text_len], reserve_size,
+						 facility, &flags, fmt, args);
+			r.info->text_len += text_len;
+
+			if (flags & LOG_NEWLINE) {
+				r.info->flags |= LOG_NEWLINE;
+				prb_final_commit(&e);
+			} else {
+				prb_commit(&e);
+			}
+
+			ret = text_len;
+			goto out;
+		}
+	}
+
+	/*
+	 * Explicitly initialize the record before every prb_reserve() call.
+	 * prb_reserve_in_last() and prb_reserve() purposely invalidate the
+	 * structure when they fail.
+	 */
+	prb_rec_init_wr(&r, reserve_size);
+	if (!prb_reserve(&e, prb, &r)) {
+		/* truncate the message if it is too long for empty buffer */
+		truncate_msg(&reserve_size, &trunc_msg_len);
+
+		prb_rec_init_wr(&r, reserve_size + trunc_msg_len);
+		if (!prb_reserve(&e, prb, &r))
+			goto out;
+	}
+
+	/* fill message */
+	text_len = printk_sprint(&r.text_buf[0], reserve_size, facility, &flags, fmt, args);
+	if (trunc_msg_len)
+		memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len);
+	r.info->text_len = text_len + trunc_msg_len;
+	r.info->facility = facility;
+	r.info->level = level & 7;
+	r.info->flags = flags & 0x1f;
+	r.info->ts_nsec = ts_nsec;
+	r.info->caller_id = caller_id;
+	if (dev_info)
+		memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info));
+
+	/* A message without a trailing newline can be continued. */
+	if (!(flags & LOG_NEWLINE))
+		prb_commit(&e);
+	else
+		prb_final_commit(&e);
+
+	ret = text_len + trunc_msg_len;
+out:
+	printk_exit_irqrestore(recursion_ptr, irqflags);
+	return ret;
+}
+
+asmlinkage int vprintk_emit(int facility, int level,
+			    const struct dev_printk_info *dev_info,
+			    const char *fmt, va_list args)
+{
+	int printed_len;
+	bool in_sched = false;
+
+	/* Suppress unimportant messages after panic happens */
+	if (unlikely(suppress_printk))
+		return 0;
+
+	if (unlikely(suppress_panic_printk) &&
+	    atomic_read(&panic_cpu) != raw_smp_processor_id())
+		return 0;
+
+	if (level == LOGLEVEL_SCHED) {
+		level = LOGLEVEL_DEFAULT;
+		in_sched = true;
+	}
+
+	printk_delay(level);
+
+	printed_len = vprintk_store(facility, level, dev_info, fmt, args);
+
+	/* If called from the scheduler, we can not call up(). */
+	if (!in_sched) {
+		/*
+		 * The caller may be holding system-critical or
+		 * timing-sensitive locks. Disable preemption during
+		 * printing of all remaining records to all consoles so that
+		 * this context can return as soon as possible. Hopefully
+		 * another printk() caller will take over the printing.
+		 */
+		preempt_disable();
+		/*
+		 * Try to acquire and then immediately release the console
+		 * semaphore. The release will print out buffers. With the
+		 * spinning variant, this context tries to take over the
+		 * printing from another printing context.
+		 */
+		if (console_trylock_spinning())
+			console_unlock();
+		preempt_enable();
+	}
+
+	if (in_sched)
+		defer_console_output();
+	else
+		wake_up_klogd();
+
+	return printed_len;
+}
+EXPORT_SYMBOL(vprintk_emit);
+
+int vprintk_default(const char *fmt, va_list args)
+{
+	return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, fmt, args);
+}
+EXPORT_SYMBOL_GPL(vprintk_default);
+
+asmlinkage __visible int _printk(const char *fmt, ...)
+{
+	va_list args;
+	int r;
+
+	va_start(args, fmt);
+	r = vprintk(fmt, args);
+	va_end(args);
+
+	return r;
+}
+EXPORT_SYMBOL(_printk);
+
+static bool pr_flush(int timeout_ms, bool reset_on_progress);
+static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress);
+
+#else /* CONFIG_PRINTK */
+
+#define CONSOLE_LOG_MAX		0
+#define DROPPED_TEXT_MAX	0
+#define printk_time		false
+
+#define prb_read_valid(rb, seq, r)	false
+#define prb_first_valid_seq(rb)		0
+#define prb_next_seq(rb)		0
+
+static u64 syslog_seq;
+
+static size_t record_print_text(const struct printk_record *r,
+				bool syslog, bool time)
+{
+	return 0;
+}
+static ssize_t info_print_ext_header(char *buf, size_t size,
+				     struct printk_info *info)
+{
+	return 0;
+}
+static ssize_t msg_print_ext_body(char *buf, size_t size,
+				  char *text, size_t text_len,
+				  struct dev_printk_info *dev_info) { return 0; }
+static void console_lock_spinning_enable(void) { }
+static int console_lock_spinning_disable_and_check(void) { return 0; }
+static void call_console_driver(struct console *con, const char *text, size_t len,
+				char *dropped_text)
+{
+}
+static bool suppress_message_printing(int level) { return false; }
+static bool pr_flush(int timeout_ms, bool reset_on_progress) { return true; }
+static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress) { return true; }
+
+#endif /* CONFIG_PRINTK */
+
+#ifdef CONFIG_EARLY_PRINTK
+struct console *early_console;
+
+asmlinkage __visible void early_printk(const char *fmt, ...)
+{
+	va_list ap;
+	char buf[512];
+	int n;
+
+	if (!early_console)
+		return;
+
+	va_start(ap, fmt);
+	n = vscnprintf(buf, sizeof(buf), fmt, ap);
+	va_end(ap);
+
+	early_console->write(early_console, buf, n);
+}
+#endif
+
+static void set_user_specified(struct console_cmdline *c, bool user_specified)
+{
+	if (!user_specified)
+		return;
+
+	/*
+	 * @c console was defined by the user on the command line.
+	 * Do not clear when added twice also by SPCR or the device tree.
+	 */
+	c->user_specified = true;
+	/* At least one console defined by the user on the command line. */
+	console_set_on_cmdline = 1;
+}
+
+static int __add_preferred_console(char *name, int idx, char *options,
+				   char *brl_options, bool user_specified)
+{
+	struct console_cmdline *c;
+	int i;
+
+	/*
+	 *	See if this tty is not yet registered, and
+	 *	if we have a slot free.
+	 */
+	for (i = 0, c = console_cmdline;
+	     i < MAX_CMDLINECONSOLES && c->name[0];
+	     i++, c++) {
+		if (strcmp(c->name, name) == 0 && c->index == idx) {
+			if (!brl_options)
+				preferred_console = i;
+			set_user_specified(c, user_specified);
+			return 0;
+		}
+	}
+	if (i == MAX_CMDLINECONSOLES)
+		return -E2BIG;
+	if (!brl_options)
+		preferred_console = i;
+	strlcpy(c->name, name, sizeof(c->name));
+	c->options = options;
+	set_user_specified(c, user_specified);
+	braille_set_options(c, brl_options);
+
+	c->index = idx;
+	return 0;
+}
+
+static int __init console_msg_format_setup(char *str)
+{
+	if (!strcmp(str, "syslog"))
+		console_msg_format = MSG_FORMAT_SYSLOG;
+	if (!strcmp(str, "default"))
+		console_msg_format = MSG_FORMAT_DEFAULT;
+	return 1;
+}
+__setup("console_msg_format=", console_msg_format_setup);
+
+/*
+ * Set up a console.  Called via do_early_param() in init/main.c
+ * for each "console=" parameter in the boot command line.
+ */
+static int __init console_setup(char *str)
+{
+	char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for "ttyS" */
+	char *s, *options, *brl_options = NULL;
+	int idx;
+
+	/*
+	 * console="" or console=null have been suggested as a way to
+	 * disable console output. Use ttynull that has been created
+	 * for exactly this purpose.
+	 */
+	if (str[0] == 0 || strcmp(str, "null") == 0) {
+		__add_preferred_console("ttynull", 0, NULL, NULL, true);
+		return 1;
+	}
+
+	if (_braille_console_setup(&str, &brl_options))
+		return 1;
+
+	/*
+	 * Decode str into name, index, options.
+	 */
+	if (str[0] >= '0' && str[0] <= '9') {
+		strcpy(buf, "ttyS");
+		strncpy(buf + 4, str, sizeof(buf) - 5);
+	} else {
+		strncpy(buf, str, sizeof(buf) - 1);
+	}
+	buf[sizeof(buf) - 1] = 0;
+	options = strchr(str, ',');
+	if (options)
+		*(options++) = 0;
+#ifdef __sparc__
+	if (!strcmp(str, "ttya"))
+		strcpy(buf, "ttyS0");
+	if (!strcmp(str, "ttyb"))
+		strcpy(buf, "ttyS1");
+#endif
+	for (s = buf; *s; s++)
+		if (isdigit(*s) || *s == ',')
+			break;
+	idx = simple_strtoul(s, NULL, 10);
+	*s = 0;
+
+	__add_preferred_console(buf, idx, options, brl_options, true);
+	return 1;
+}
+__setup("console=", console_setup);
+
+/**
+ * add_preferred_console - add a device to the list of preferred consoles.
+ * @name: device name
+ * @idx: device index
+ * @options: options for this console
+ *
+ * The last preferred console added will be used for kernel messages
+ * and stdin/out/err for init.  Normally this is used by console_setup
+ * above to handle user-supplied console arguments; however it can also
+ * be used by arch-specific code either to override the user or more
+ * commonly to provide a default console (ie from PROM variables) when
+ * the user has not supplied one.
+ */
+int add_preferred_console(char *name, int idx, char *options)
+{
+	return __add_preferred_console(name, idx, options, NULL, false);
+}
+
+bool console_suspend_enabled = true;
+EXPORT_SYMBOL(console_suspend_enabled);
+
+static int __init console_suspend_disable(char *str)
+{
+	console_suspend_enabled = false;
+	return 1;
+}
+__setup("no_console_suspend", console_suspend_disable);
+module_param_named(console_suspend, console_suspend_enabled,
+		bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(console_suspend, "suspend console during suspend"
+	" and hibernate operations");
+
+static bool printk_console_no_auto_verbose;
+
+void console_verbose(void)
+{
+	if (console_loglevel && !printk_console_no_auto_verbose)
+		console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
+}
+EXPORT_SYMBOL_GPL(console_verbose);
+
+module_param_named(console_no_auto_verbose, printk_console_no_auto_verbose, bool, 0644);
+MODULE_PARM_DESC(console_no_auto_verbose, "Disable console loglevel raise to highest on oops/panic/etc");
+
+/**
+ * suspend_console - suspend the console subsystem
+ *
+ * This disables printk() while we go into suspend states
+ */
+void suspend_console(void)
+{
+	if (!console_suspend_enabled)
+		return;
+	pr_info("Suspending console(s) (use no_console_suspend to debug)\n");
+	pr_flush(1000, true);
+	console_lock();
+	console_suspended = 1;
+	up_console_sem();
+}
+
+void resume_console(void)
+{
+	if (!console_suspend_enabled)
+		return;
+	down_console_sem();
+	console_suspended = 0;
+	console_unlock();
+	pr_flush(1000, true);
+}
+
+/**
+ * console_cpu_notify - print deferred console messages after CPU hotplug
+ * @cpu: unused
+ *
+ * If printk() is called from a CPU that is not online yet, the messages
+ * will be printed on the console only if there are CON_ANYTIME consoles.
+ * This function is called when a new CPU comes online (or fails to come
+ * up) or goes offline.
+ */
+static int console_cpu_notify(unsigned int cpu)
+{
+	if (!cpuhp_tasks_frozen) {
+		/* If trylock fails, someone else is doing the printing */
+		if (console_trylock())
+			console_unlock();
+	}
+	return 0;
+}
+
+/*
+ * Return true when this CPU should unlock console_sem without pushing all
+ * messages to the console. This reduces the chance that the console is
+ * locked when the panic CPU tries to use it.
+ */
+static bool abandon_console_lock_in_panic(void)
+{
+	if (!panic_in_progress())
+		return false;
+
+	/*
+	 * We can use raw_smp_processor_id() here because it is impossible for
+	 * the task to be migrated to the panic_cpu, or away from it. If
+	 * panic_cpu has already been set, and we're not currently executing on
+	 * that CPU, then we never will be.
+	 */
+	return atomic_read(&panic_cpu) != raw_smp_processor_id();
+}
+
+/**
+ * console_lock - lock the console system for exclusive use.
+ *
+ * Acquires a lock which guarantees that the caller has
+ * exclusive access to the console system and the console_drivers list.
+ *
+ * Can sleep, returns nothing.
+ */
+void console_lock(void)
+{
+	might_sleep();
+
+	/* On panic, the console_lock must be left to the panic cpu. */
+	while (abandon_console_lock_in_panic())
+		msleep(1000);
+
+	down_console_sem();
+	if (console_suspended)
+		return;
+	console_locked = 1;
+	console_may_schedule = 1;
+}
+EXPORT_SYMBOL(console_lock);
+
+/**
+ * console_trylock - try to lock the console system for exclusive use.
+ *
+ * Try to acquire a lock which guarantees that the caller has exclusive
+ * access to the console system and the console_drivers list.
+ *
+ * returns 1 on success, and 0 on failure to acquire the lock.
+ */
+int console_trylock(void)
+{
+	/* On panic, the console_lock must be left to the panic cpu. */
+	if (abandon_console_lock_in_panic())
+		return 0;
+	if (down_trylock_console_sem())
+		return 0;
+	if (console_suspended) {
+		up_console_sem();
+		return 0;
+	}
+	console_locked = 1;
+	console_may_schedule = 0;
+	return 1;
+}
+EXPORT_SYMBOL(console_trylock);
+
+int is_console_locked(void)
+{
+	return console_locked;
+}
+EXPORT_SYMBOL(is_console_locked);
+
+/*
+ * Check if the given console is currently capable and allowed to print
+ * records.
+ *
+ * Requires the console_lock.
+ */
+static inline bool console_is_usable(struct console *con)
+{
+	if (!(con->flags & CON_ENABLED))
+		return false;
+
+	if (!con->write)
+		return false;
+
+	/*
+	 * Console drivers may assume that per-cpu resources have been
+	 * allocated. So unless they're explicitly marked as being able to
+	 * cope (CON_ANYTIME) don't call them until this CPU is officially up.
+	 */
+	if (!cpu_online(raw_smp_processor_id()) &&
+	    !(con->flags & CON_ANYTIME))
+		return false;
+
+	return true;
+}
+
+static void __console_unlock(void)
+{
+	console_locked = 0;
+	up_console_sem();
+}
+
+/*
+ * Print one record for the given console. The record printed is whatever
+ * record is the next available record for the given console.
+ *
+ * @text is a buffer of size CONSOLE_LOG_MAX.
+ *
+ * If extended messages should be printed, @ext_text is a buffer of size
+ * CONSOLE_EXT_LOG_MAX. Otherwise @ext_text must be NULL.
+ *
+ * If dropped messages should be printed, @dropped_text is a buffer of size
+ * DROPPED_TEXT_MAX. Otherwise @dropped_text must be NULL.
+ *
+ * @handover will be set to true if a printk waiter has taken over the
+ * console_lock, in which case the caller is no longer holding the
+ * console_lock. Otherwise it is set to false.
+ *
+ * Returns false if the given console has no next record to print, otherwise
+ * true.
+ *
+ * Requires the console_lock.
+ */
+static bool console_emit_next_record(struct console *con, char *text, char *ext_text,
+				     char *dropped_text, bool *handover)
+{
+	static int panic_console_dropped;
+	struct printk_info info;
+	struct printk_record r;
+	unsigned long flags;
+	char *write_text;
+	size_t len;
+
+	prb_rec_init_rd(&r, &info, text, CONSOLE_LOG_MAX);
+
+	*handover = false;
+
+	if (!prb_read_valid(prb, con->seq, &r))
+		return false;
+
+	if (con->seq != r.info->seq) {
+		con->dropped += r.info->seq - con->seq;
+		con->seq = r.info->seq;
+		if (panic_in_progress() && panic_console_dropped++ > 10) {
+			suppress_panic_printk = 1;
+			pr_warn_once("Too many dropped messages. Suppress messages on non-panic CPUs to prevent livelock.\n");
+		}
+	}
+
+	/* Skip record that has level above the console loglevel. */
+	if (suppress_message_printing(r.info->level)) {
+		con->seq++;
+		goto skip;
+	}
+
+	if (ext_text) {
+		write_text = ext_text;
+		len = info_print_ext_header(ext_text, CONSOLE_EXT_LOG_MAX, r.info);
+		len += msg_print_ext_body(ext_text + len, CONSOLE_EXT_LOG_MAX - len,
+					  &r.text_buf[0], r.info->text_len, &r.info->dev_info);
+	} else {
+		write_text = text;
+		len = record_print_text(&r, console_msg_format & MSG_FORMAT_SYSLOG, printk_time);
+	}
+
+	/*
+	 * While actively printing out messages, if another printk()
+	 * were to occur on another CPU, it may wait for this one to
+	 * finish. This task can not be preempted if there is a
+	 * waiter waiting to take over.
+	 *
+	 * Interrupts are disabled because the hand over to a waiter
+	 * must not be interrupted until the hand over is completed
+	 * (@console_waiter is cleared).
+	 */
+	printk_safe_enter_irqsave(flags);
+	console_lock_spinning_enable();
+
+	stop_critical_timings();	/* don't trace print latency */
+	call_console_driver(con, write_text, len, dropped_text);
+	start_critical_timings();
+
+	con->seq++;
+
+	*handover = console_lock_spinning_disable_and_check();
+	printk_safe_exit_irqrestore(flags);
+skip:
+	return true;
+}
+
+/*
+ * Print out all remaining records to all consoles.
+ *
+ * @do_cond_resched is set by the caller. It can be true only in schedulable
+ * context.
+ *
+ * @next_seq is set to the sequence number after the last available record.
+ * The value is valid only when this function returns true. It means that all
+ * usable consoles are completely flushed.
+ *
+ * @handover will be set to true if a printk waiter has taken over the
+ * console_lock, in which case the caller is no longer holding the
+ * console_lock. Otherwise it is set to false.
+ *
+ * Returns true when there was at least one usable console and all messages
+ * were flushed to all usable consoles. A returned false informs the caller
+ * that everything was not flushed (either there were no usable consoles or
+ * another context has taken over printing or it is a panic situation and this
+ * is not the panic CPU). Regardless the reason, the caller should assume it
+ * is not useful to immediately try again.
+ *
+ * Requires the console_lock.
+ */
+static bool console_flush_all(bool do_cond_resched, u64 *next_seq, bool *handover)
+{
+	static char dropped_text[DROPPED_TEXT_MAX];
+	static char ext_text[CONSOLE_EXT_LOG_MAX];
+	static char text[CONSOLE_LOG_MAX];
+	bool any_usable = false;
+	struct console *con;
+	bool any_progress;
+
+	*next_seq = 0;
+	*handover = false;
+
+	do {
+		any_progress = false;
+
+		for_each_console(con) {
+			bool progress;
+
+			if (!console_is_usable(con))
+				continue;
+			any_usable = true;
+
+			if (con->flags & CON_EXTENDED) {
+				/* Extended consoles do not print "dropped messages". */
+				progress = console_emit_next_record(con, &text[0],
+								    &ext_text[0], NULL,
+								    handover);
+			} else {
+				progress = console_emit_next_record(con, &text[0],
+								    NULL, &dropped_text[0],
+								    handover);
+			}
+			if (*handover)
+				return false;
+
+			/* Track the next of the highest seq flushed. */
+			if (con->seq > *next_seq)
+				*next_seq = con->seq;
+
+			if (!progress)
+				continue;
+			any_progress = true;
+
+			/* Allow panic_cpu to take over the consoles safely. */
+			if (abandon_console_lock_in_panic())
+				return false;
+
+			if (do_cond_resched)
+				cond_resched();
+		}
+	} while (any_progress);
+
+	return any_usable;
+}
+
+/**
+ * console_unlock - unlock the console system
+ *
+ * Releases the console_lock which the caller holds on the console system
+ * and the console driver list.
+ *
+ * While the console_lock was held, console output may have been buffered
+ * by printk().  If this is the case, console_unlock(); emits
+ * the output prior to releasing the lock.
+ *
+ * console_unlock(); may be called from any context.
+ */
+void console_unlock(void)
+{
+	bool do_cond_resched;
+	bool handover;
+	bool flushed;
+	u64 next_seq;
+
+	if (console_suspended) {
+		up_console_sem();
+		return;
+	}
+
+	/*
+	 * Console drivers are called with interrupts disabled, so
+	 * @console_may_schedule should be cleared before; however, we may
+	 * end up dumping a lot of lines, for example, if called from
+	 * console registration path, and should invoke cond_resched()
+	 * between lines if allowable.  Not doing so can cause a very long
+	 * scheduling stall on a slow console leading to RCU stall and
+	 * softlockup warnings which exacerbate the issue with more
+	 * messages practically incapacitating the system. Therefore, create
+	 * a local to use for the printing loop.
+	 */
+	do_cond_resched = console_may_schedule;
+
+	do {
+		console_may_schedule = 0;
+
+		flushed = console_flush_all(do_cond_resched, &next_seq, &handover);
+		if (!handover)
+			__console_unlock();
+
+		/*
+		 * Abort if there was a failure to flush all messages to all
+		 * usable consoles. Either it is not possible to flush (in
+		 * which case it would be an infinite loop of retrying) or
+		 * another context has taken over printing.
+		 */
+		if (!flushed)
+			break;
+
+		/*
+		 * Some context may have added new records after
+		 * console_flush_all() but before unlocking the console.
+		 * Re-check if there is a new record to flush. If the trylock
+		 * fails, another context is already handling the printing.
+		 */
+	} while (prb_read_valid(prb, next_seq, NULL) && console_trylock());
+}
+EXPORT_SYMBOL(console_unlock);
+
+/**
+ * console_conditional_schedule - yield the CPU if required
+ *
+ * If the console code is currently allowed to sleep, and
+ * if this CPU should yield the CPU to another task, do
+ * so here.
+ *
+ * Must be called within console_lock();.
+ */
+void __sched console_conditional_schedule(void)
+{
+	if (console_may_schedule)
+		cond_resched();
+}
+EXPORT_SYMBOL(console_conditional_schedule);
+
+void console_unblank(void)
+{
+	struct console *c;
+
+	/*
+	 * console_unblank can no longer be called in interrupt context unless
+	 * oops_in_progress is set to 1..
+	 */
+	if (oops_in_progress) {
+		if (down_trylock_console_sem() != 0)
+			return;
+	} else
+		console_lock();
+
+	console_locked = 1;
+	console_may_schedule = 0;
+	for_each_console(c)
+		if ((c->flags & CON_ENABLED) && c->unblank)
+			c->unblank();
+	console_unlock();
+
+	if (!oops_in_progress)
+		pr_flush(1000, true);
+}
+
+/**
+ * console_flush_on_panic - flush console content on panic
+ * @mode: flush all messages in buffer or just the pending ones
+ *
+ * Immediately output all pending messages no matter what.
+ */
+void console_flush_on_panic(enum con_flush_mode mode)
+{
+	/*
+	 * If someone else is holding the console lock, trylock will fail
+	 * and may_schedule may be set.  Ignore and proceed to unlock so
+	 * that messages are flushed out.  As this can be called from any
+	 * context and we don't want to get preempted while flushing,
+	 * ensure may_schedule is cleared.
+	 */
+	console_trylock();
+	console_may_schedule = 0;
+
+	if (mode == CONSOLE_REPLAY_ALL) {
+		struct console *c;
+		u64 seq;
+
+		seq = prb_first_valid_seq(prb);
+		for_each_console(c)
+			c->seq = seq;
+	}
+	console_unlock();
+}
+
+/*
+ * Return the console tty driver structure and its associated index
+ */
+struct tty_driver *console_device(int *index)
+{
+	struct console *c;
+	struct tty_driver *driver = NULL;
+
+	console_lock();
+	for_each_console(c) {
+		if (!c->device)
+			continue;
+		driver = c->device(c, index);
+		if (driver)
+			break;
+	}
+	console_unlock();
+	return driver;
+}
+
+/*
+ * Prevent further output on the passed console device so that (for example)
+ * serial drivers can disable console output before suspending a port, and can
+ * re-enable output afterwards.
+ */
+void console_stop(struct console *console)
+{
+	__pr_flush(console, 1000, true);
+	console_lock();
+	console->flags &= ~CON_ENABLED;
+	console_unlock();
+}
+EXPORT_SYMBOL(console_stop);
+
+void console_start(struct console *console)
+{
+	console_lock();
+	console->flags |= CON_ENABLED;
+	console_unlock();
+	__pr_flush(console, 1000, true);
+}
+EXPORT_SYMBOL(console_start);
+
+static int __read_mostly keep_bootcon;
+
+static int __init keep_bootcon_setup(char *str)
+{
+	keep_bootcon = 1;
+	pr_info("debug: skip boot console de-registration.\n");
+
+	return 0;
+}
+
+early_param("keep_bootcon", keep_bootcon_setup);
+
+/*
+ * This is called by register_console() to try to match
+ * the newly registered console with any of the ones selected
+ * by either the command line or add_preferred_console() and
+ * setup/enable it.
+ *
+ * Care need to be taken with consoles that are statically
+ * enabled such as netconsole
+ */
+static int try_enable_preferred_console(struct console *newcon,
+					bool user_specified)
+{
+	struct console_cmdline *c;
+	int i, err;
+
+	for (i = 0, c = console_cmdline;
+	     i < MAX_CMDLINECONSOLES && c->name[0];
+	     i++, c++) {
+		if (c->user_specified != user_specified)
+			continue;
+		if (!newcon->match ||
+		    newcon->match(newcon, c->name, c->index, c->options) != 0) {
+			/* default matching */
+			BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name));
+			if (strcmp(c->name, newcon->name) != 0)
+				continue;
+			if (newcon->index >= 0 &&
+			    newcon->index != c->index)
+				continue;
+			if (newcon->index < 0)
+				newcon->index = c->index;
+
+			if (_braille_register_console(newcon, c))
+				return 0;
+
+			if (newcon->setup &&
+			    (err = newcon->setup(newcon, c->options)) != 0)
+				return err;
+		}
+		newcon->flags |= CON_ENABLED;
+		if (i == preferred_console)
+			newcon->flags |= CON_CONSDEV;
+		return 0;
+	}
+
+	/*
+	 * Some consoles, such as pstore and netconsole, can be enabled even
+	 * without matching. Accept the pre-enabled consoles only when match()
+	 * and setup() had a chance to be called.
+	 */
+	if (newcon->flags & CON_ENABLED && c->user_specified ==	user_specified)
+		return 0;
+
+	return -ENOENT;
+}
+
+/* Try to enable the console unconditionally */
+static void try_enable_default_console(struct console *newcon)
+{
+	if (newcon->index < 0)
+		newcon->index = 0;
+
+	if (newcon->setup && newcon->setup(newcon, NULL) != 0)
+		return;
+
+	newcon->flags |= CON_ENABLED;
+
+	if (newcon->device)
+		newcon->flags |= CON_CONSDEV;
+}
+
+#define con_printk(lvl, con, fmt, ...)			\
+	printk(lvl pr_fmt("%sconsole [%s%d] " fmt),	\
+	       (con->flags & CON_BOOT) ? "boot" : "",	\
+	       con->name, con->index, ##__VA_ARGS__)
+
+/*
+ * The console driver calls this routine during kernel initialization
+ * to register the console printing procedure with printk() and to
+ * print any messages that were printed by the kernel before the
+ * console driver was initialized.
+ *
+ * This can happen pretty early during the boot process (because of
+ * early_printk) - sometimes before setup_arch() completes - be careful
+ * of what kernel features are used - they may not be initialised yet.
+ *
+ * There are two types of consoles - bootconsoles (early_printk) and
+ * "real" consoles (everything which is not a bootconsole) which are
+ * handled differently.
+ *  - Any number of bootconsoles can be registered at any time.
+ *  - As soon as a "real" console is registered, all bootconsoles
+ *    will be unregistered automatically.
+ *  - Once a "real" console is registered, any attempt to register a
+ *    bootconsoles will be rejected
+ */
+void register_console(struct console *newcon)
+{
+	struct console *con;
+	bool bootcon_enabled = false;
+	bool realcon_enabled = false;
+	int err;
+
+	for_each_console(con) {
+		if (WARN(con == newcon, "console '%s%d' already registered\n",
+					 con->name, con->index))
+			return;
+	}
+
+	for_each_console(con) {
+		if (con->flags & CON_BOOT)
+			bootcon_enabled = true;
+		else
+			realcon_enabled = true;
+	}
+
+	/* Do not register boot consoles when there already is a real one. */
+	if (newcon->flags & CON_BOOT && realcon_enabled) {
+		pr_info("Too late to register bootconsole %s%d\n",
+			newcon->name, newcon->index);
+		return;
+	}
+
+	/*
+	 * See if we want to enable this console driver by default.
+	 *
+	 * Nope when a console is preferred by the command line, device
+	 * tree, or SPCR.
+	 *
+	 * The first real console with tty binding (driver) wins. More
+	 * consoles might get enabled before the right one is found.
+	 *
+	 * Note that a console with tty binding will have CON_CONSDEV
+	 * flag set and will be first in the list.
+	 */
+	if (preferred_console < 0) {
+		if (!console_drivers || !console_drivers->device ||
+		    console_drivers->flags & CON_BOOT) {
+			try_enable_default_console(newcon);
+		}
+	}
+
+	/* See if this console matches one we selected on the command line */
+	err = try_enable_preferred_console(newcon, true);
+
+	/* If not, try to match against the platform default(s) */
+	if (err == -ENOENT)
+		err = try_enable_preferred_console(newcon, false);
+
+	/* printk() messages are not printed to the Braille console. */
+	if (err || newcon->flags & CON_BRL)
+		return;
+
+	/*
+	 * If we have a bootconsole, and are switching to a real console,
+	 * don't print everything out again, since when the boot console, and
+	 * the real console are the same physical device, it's annoying to
+	 * see the beginning boot messages twice
+	 */
+	if (bootcon_enabled &&
+	    ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) {
+		newcon->flags &= ~CON_PRINTBUFFER;
+	}
+
+	/*
+	 *	Put this console in the list - keep the
+	 *	preferred driver at the head of the list.
+	 */
+	console_lock();
+	if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) {
+		newcon->next = console_drivers;
+		console_drivers = newcon;
+		if (newcon->next)
+			newcon->next->flags &= ~CON_CONSDEV;
+		/* Ensure this flag is always set for the head of the list */
+		newcon->flags |= CON_CONSDEV;
+	} else {
+		newcon->next = console_drivers->next;
+		console_drivers->next = newcon;
+	}
+
+	newcon->dropped = 0;
+	if (newcon->flags & CON_PRINTBUFFER) {
+		/* Get a consistent copy of @syslog_seq. */
+		mutex_lock(&syslog_lock);
+		newcon->seq = syslog_seq;
+		mutex_unlock(&syslog_lock);
+	} else {
+		/* Begin with next message. */
+		newcon->seq = prb_next_seq(prb);
+	}
+	console_unlock();
+	console_sysfs_notify();
+
+	/*
+	 * By unregistering the bootconsoles after we enable the real console
+	 * we get the "console xxx enabled" message on all the consoles -
+	 * boot consoles, real consoles, etc - this is to ensure that end
+	 * users know there might be something in the kernel's log buffer that
+	 * went to the bootconsole (that they do not see on the real console)
+	 */
+	con_printk(KERN_INFO, newcon, "enabled\n");
+	if (bootcon_enabled &&
+	    ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) &&
+	    !keep_bootcon) {
+		for_each_console(con)
+			if (con->flags & CON_BOOT)
+				unregister_console(con);
+	}
+}
+EXPORT_SYMBOL(register_console);
+
+int unregister_console(struct console *console)
+{
+	struct console *con;
+	int res;
+
+	con_printk(KERN_INFO, console, "disabled\n");
+
+	res = _braille_unregister_console(console);
+	if (res < 0)
+		return res;
+	if (res > 0)
+		return 0;
+
+	res = -ENODEV;
+	console_lock();
+	if (console_drivers == console) {
+		console_drivers=console->next;
+		res = 0;
+	} else {
+		for_each_console(con) {
+			if (con->next == console) {
+				con->next = console->next;
+				res = 0;
+				break;
+			}
+		}
+	}
+
+	if (res)
+		goto out_disable_unlock;
+
+	/*
+	 * If this isn't the last console and it has CON_CONSDEV set, we
+	 * need to set it on the next preferred console.
+	 */
+	if (console_drivers != NULL && console->flags & CON_CONSDEV)
+		console_drivers->flags |= CON_CONSDEV;
+
+	console->flags &= ~CON_ENABLED;
+	console_unlock();
+	console_sysfs_notify();
+
+	if (console->exit)
+		res = console->exit(console);
+
+	return res;
+
+out_disable_unlock:
+	console->flags &= ~CON_ENABLED;
+	console_unlock();
+
+	return res;
+}
+EXPORT_SYMBOL(unregister_console);
+
+/*
+ * Initialize the console device. This is called *early*, so
+ * we can't necessarily depend on lots of kernel help here.
+ * Just do some early initializations, and do the complex setup
+ * later.
+ */
+void __init console_init(void)
+{
+	int ret;
+	initcall_t call;
+	initcall_entry_t *ce;
+
+	/* Setup the default TTY line discipline. */
+	n_tty_init();
+
+	/*
+	 * set up the console device so that later boot sequences can
+	 * inform about problems etc..
+	 */
+	ce = __con_initcall_start;
+	trace_initcall_level("console");
+	while (ce < __con_initcall_end) {
+		call = initcall_from_entry(ce);
+		trace_initcall_start(call);
+		ret = call();
+		trace_initcall_finish(call, ret);
+		ce++;
+	}
+}
+
+/*
+ * Some boot consoles access data that is in the init section and which will
+ * be discarded after the initcalls have been run. To make sure that no code
+ * will access this data, unregister the boot consoles in a late initcall.
+ *
+ * If for some reason, such as deferred probe or the driver being a loadable
+ * module, the real console hasn't registered yet at this point, there will
+ * be a brief interval in which no messages are logged to the console, which
+ * makes it difficult to diagnose problems that occur during this time.
+ *
+ * To mitigate this problem somewhat, only unregister consoles whose memory
+ * intersects with the init section. Note that all other boot consoles will
+ * get unregistered when the real preferred console is registered.
+ */
+static int __init printk_late_init(void)
+{
+	struct console *con;
+	int ret;
+
+	for_each_console(con) {
+		if (!(con->flags & CON_BOOT))
+			continue;
+
+		/* Check addresses that might be used for enabled consoles. */
+		if (init_section_intersects(con, sizeof(*con)) ||
+		    init_section_contains(con->write, 0) ||
+		    init_section_contains(con->read, 0) ||
+		    init_section_contains(con->device, 0) ||
+		    init_section_contains(con->unblank, 0) ||
+		    init_section_contains(con->data, 0)) {
+			/*
+			 * Please, consider moving the reported consoles out
+			 * of the init section.
+			 */
+			pr_warn("bootconsole [%s%d] uses init memory and must be disabled even before the real one is ready\n",
+				con->name, con->index);
+			unregister_console(con);
+		}
+	}
+	ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL,
+					console_cpu_notify);
+	WARN_ON(ret < 0);
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "printk:online",
+					console_cpu_notify, NULL);
+	WARN_ON(ret < 0);
+	printk_sysctl_init();
+	return 0;
+}
+late_initcall(printk_late_init);
+
+#if defined CONFIG_PRINTK
+/* If @con is specified, only wait for that console. Otherwise wait for all. */
+static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress)
+{
+	int remaining = timeout_ms;
+	struct console *c;
+	u64 last_diff = 0;
+	u64 printk_seq;
+	u64 diff;
+	u64 seq;
+
+	might_sleep();
+
+	seq = prb_next_seq(prb);
+
+	for (;;) {
+		diff = 0;
+
+		console_lock();
+
+		for_each_console(c) {
+			if (con && con != c)
+				continue;
+			if (!console_is_usable(c))
+				continue;
+			printk_seq = c->seq;
+			if (printk_seq < seq)
+				diff += seq - printk_seq;
+		}
+
+		/*
+		 * If consoles are suspended, it cannot be expected that they
+		 * make forward progress, so timeout immediately. @diff is
+		 * still used to return a valid flush status.
+		 */
+		if (console_suspended)
+			remaining = 0;
+		else if (diff != last_diff && reset_on_progress)
+			remaining = timeout_ms;
+
+		console_unlock();
+
+		if (diff == 0 || remaining == 0)
+			break;
+
+		if (remaining < 0) {
+			/* no timeout limit */
+			msleep(100);
+		} else if (remaining < 100) {
+			msleep(remaining);
+			remaining = 0;
+		} else {
+			msleep(100);
+			remaining -= 100;
+		}
+
+		last_diff = diff;
+	}
+
+	return (diff == 0);
+}
+
+/**
+ * pr_flush() - Wait for printing threads to catch up.
+ *
+ * @timeout_ms:        The maximum time (in ms) to wait.
+ * @reset_on_progress: Reset the timeout if forward progress is seen.
+ *
+ * A value of 0 for @timeout_ms means no waiting will occur. A value of -1
+ * represents infinite waiting.
+ *
+ * If @reset_on_progress is true, the timeout will be reset whenever any
+ * printer has been seen to make some forward progress.
+ *
+ * Context: Process context. May sleep while acquiring console lock.
+ * Return: true if all enabled printers are caught up.
+ */
+static bool pr_flush(int timeout_ms, bool reset_on_progress)
+{
+	return __pr_flush(NULL, timeout_ms, reset_on_progress);
+}
+
+/*
+ * Delayed printk version, for scheduler-internal messages:
+ */
+#define PRINTK_PENDING_WAKEUP	0x01
+#define PRINTK_PENDING_OUTPUT	0x02
+
+static DEFINE_PER_CPU(int, printk_pending);
+
+static void wake_up_klogd_work_func(struct irq_work *irq_work)
+{
+	int pending = this_cpu_xchg(printk_pending, 0);
+
+	if (pending & PRINTK_PENDING_OUTPUT) {
+		/* If trylock fails, someone else is doing the printing */
+		if (console_trylock())
+			console_unlock();
+	}
+
+	if (pending & PRINTK_PENDING_WAKEUP)
+		wake_up_interruptible(&log_wait);
+}
+
+static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) =
+	IRQ_WORK_INIT_LAZY(wake_up_klogd_work_func);
+
+static void __wake_up_klogd(int val)
+{
+	if (!printk_percpu_data_ready())
+		return;
+
+	preempt_disable();
+	/*
+	 * Guarantee any new records can be seen by tasks preparing to wait
+	 * before this context checks if the wait queue is empty.
+	 *
+	 * The full memory barrier within wq_has_sleeper() pairs with the full
+	 * memory barrier within set_current_state() of
+	 * prepare_to_wait_event(), which is called after ___wait_event() adds
+	 * the waiter but before it has checked the wait condition.
+	 *
+	 * This pairs with devkmsg_read:A and syslog_print:A.
+	 */
+	if (wq_has_sleeper(&log_wait) || /* LMM(__wake_up_klogd:A) */
+	    (val & PRINTK_PENDING_OUTPUT)) {
+		this_cpu_or(printk_pending, val);
+		irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
+	}
+	preempt_enable();
+}
+
+/**
+ * wake_up_klogd - Wake kernel logging daemon
+ *
+ * Use this function when new records have been added to the ringbuffer
+ * and the console printing of those records has already occurred or is
+ * known to be handled by some other context. This function will only
+ * wake the logging daemon.
+ *
+ * Context: Any context.
+ */
+void wake_up_klogd(void)
+{
+	__wake_up_klogd(PRINTK_PENDING_WAKEUP);
+}
+
+/**
+ * defer_console_output - Wake kernel logging daemon and trigger
+ *	console printing in a deferred context
+ *
+ * Use this function when new records have been added to the ringbuffer,
+ * this context is responsible for console printing those records, but
+ * the current context is not allowed to perform the console printing.
+ * Trigger an irq_work context to perform the console printing. This
+ * function also wakes the logging daemon.
+ *
+ * Context: Any context.
+ */
+void defer_console_output(void)
+{
+	/*
+	 * New messages may have been added directly to the ringbuffer
+	 * using vprintk_store(), so wake any waiters as well.
+	 */
+	__wake_up_klogd(PRINTK_PENDING_WAKEUP | PRINTK_PENDING_OUTPUT);
+}
+
+void printk_trigger_flush(void)
+{
+	defer_console_output();
+}
+
+int vprintk_deferred(const char *fmt, va_list args)
+{
+	return vprintk_emit(0, LOGLEVEL_SCHED, NULL, fmt, args);
+}
+
+int _printk_deferred(const char *fmt, ...)
+{
+	va_list args;
+	int r;
+
+	va_start(args, fmt);
+	r = vprintk_deferred(fmt, args);
+	va_end(args);
+
+	return r;
+}
+
+/*
+ * printk rate limiting, lifted from the networking subsystem.
+ *
+ * This enforces a rate limit: not more than 10 kernel messages
+ * every 5s to make a denial-of-service attack impossible.
+ */
+DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10);
+
+int __printk_ratelimit(const char *func)
+{
+	return ___ratelimit(&printk_ratelimit_state, func);
+}
+EXPORT_SYMBOL(__printk_ratelimit);
+
+/**
+ * printk_timed_ratelimit - caller-controlled printk ratelimiting
+ * @caller_jiffies: pointer to caller's state
+ * @interval_msecs: minimum interval between prints
+ *
+ * printk_timed_ratelimit() returns true if more than @interval_msecs
+ * milliseconds have elapsed since the last time printk_timed_ratelimit()
+ * returned true.
+ */
+bool printk_timed_ratelimit(unsigned long *caller_jiffies,
+			unsigned int interval_msecs)
+{
+	unsigned long elapsed = jiffies - *caller_jiffies;
+
+	if (*caller_jiffies && elapsed <= msecs_to_jiffies(interval_msecs))
+		return false;
+
+	*caller_jiffies = jiffies;
+	return true;
+}
+EXPORT_SYMBOL(printk_timed_ratelimit);
+
+static DEFINE_SPINLOCK(dump_list_lock);
+static LIST_HEAD(dump_list);
+
+/**
+ * kmsg_dump_register - register a kernel log dumper.
+ * @dumper: pointer to the kmsg_dumper structure
+ *
+ * Adds a kernel log dumper to the system. The dump callback in the
+ * structure will be called when the kernel oopses or panics and must be
+ * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise.
+ */
+int kmsg_dump_register(struct kmsg_dumper *dumper)
+{
+	unsigned long flags;
+	int err = -EBUSY;
+
+	/* The dump callback needs to be set */
+	if (!dumper->dump)
+		return -EINVAL;
+
+	spin_lock_irqsave(&dump_list_lock, flags);
+	/* Don't allow registering multiple times */
+	if (!dumper->registered) {
+		dumper->registered = 1;
+		list_add_tail_rcu(&dumper->list, &dump_list);
+		err = 0;
+	}
+	spin_unlock_irqrestore(&dump_list_lock, flags);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_register);
+
+/**
+ * kmsg_dump_unregister - unregister a kmsg dumper.
+ * @dumper: pointer to the kmsg_dumper structure
+ *
+ * Removes a dump device from the system. Returns zero on success and
+ * %-EINVAL otherwise.
+ */
+int kmsg_dump_unregister(struct kmsg_dumper *dumper)
+{
+	unsigned long flags;
+	int err = -EINVAL;
+
+	spin_lock_irqsave(&dump_list_lock, flags);
+	if (dumper->registered) {
+		dumper->registered = 0;
+		list_del_rcu(&dumper->list);
+		err = 0;
+	}
+	spin_unlock_irqrestore(&dump_list_lock, flags);
+	synchronize_rcu();
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
+
+static bool always_kmsg_dump;
+module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
+
+const char *kmsg_dump_reason_str(enum kmsg_dump_reason reason)
+{
+	switch (reason) {
+	case KMSG_DUMP_PANIC:
+		return "Panic";
+	case KMSG_DUMP_OOPS:
+		return "Oops";
+	case KMSG_DUMP_EMERG:
+		return "Emergency";
+	case KMSG_DUMP_SHUTDOWN:
+		return "Shutdown";
+	default:
+		return "Unknown";
+	}
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_reason_str);
+
+/**
+ * kmsg_dump - dump kernel log to kernel message dumpers.
+ * @reason: the reason (oops, panic etc) for dumping
+ *
+ * Call each of the registered dumper's dump() callback, which can
+ * retrieve the kmsg records with kmsg_dump_get_line() or
+ * kmsg_dump_get_buffer().
+ */
+void kmsg_dump(enum kmsg_dump_reason reason)
+{
+	struct kmsg_dumper *dumper;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(dumper, &dump_list, list) {
+		enum kmsg_dump_reason max_reason = dumper->max_reason;
+
+		/*
+		 * If client has not provided a specific max_reason, default
+		 * to KMSG_DUMP_OOPS, unless always_kmsg_dump was set.
+		 */
+		if (max_reason == KMSG_DUMP_UNDEF) {
+			max_reason = always_kmsg_dump ? KMSG_DUMP_MAX :
+							KMSG_DUMP_OOPS;
+		}
+		if (reason > max_reason)
+			continue;
+
+		/* invoke dumper which will iterate over records */
+		dumper->dump(dumper, reason);
+	}
+	rcu_read_unlock();
+}
+
+/**
+ * kmsg_dump_get_line - retrieve one kmsg log line
+ * @iter: kmsg dump iterator
+ * @syslog: include the "<4>" prefixes
+ * @line: buffer to copy the line to
+ * @size: maximum size of the buffer
+ * @len: length of line placed into buffer
+ *
+ * Start at the beginning of the kmsg buffer, with the oldest kmsg
+ * record, and copy one record into the provided buffer.
+ *
+ * Consecutive calls will return the next available record moving
+ * towards the end of the buffer with the youngest messages.
+ *
+ * A return value of FALSE indicates that there are no more records to
+ * read.
+ */
+bool kmsg_dump_get_line(struct kmsg_dump_iter *iter, bool syslog,
+			char *line, size_t size, size_t *len)
+{
+	u64 min_seq = latched_seq_read_nolock(&clear_seq);
+	struct printk_info info;
+	unsigned int line_count;
+	struct printk_record r;
+	size_t l = 0;
+	bool ret = false;
+
+	if (iter->cur_seq < min_seq)
+		iter->cur_seq = min_seq;
+
+	prb_rec_init_rd(&r, &info, line, size);
+
+	/* Read text or count text lines? */
+	if (line) {
+		if (!prb_read_valid(prb, iter->cur_seq, &r))
+			goto out;
+		l = record_print_text(&r, syslog, printk_time);
+	} else {
+		if (!prb_read_valid_info(prb, iter->cur_seq,
+					 &info, &line_count)) {
+			goto out;
+		}
+		l = get_record_print_text_size(&info, line_count, syslog,
+					       printk_time);
+
+	}
+
+	iter->cur_seq = r.info->seq + 1;
+	ret = true;
+out:
+	if (len)
+		*len = l;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
+
+/**
+ * kmsg_dump_get_buffer - copy kmsg log lines
+ * @iter: kmsg dump iterator
+ * @syslog: include the "<4>" prefixes
+ * @buf: buffer to copy the line to
+ * @size: maximum size of the buffer
+ * @len_out: length of line placed into buffer
+ *
+ * Start at the end of the kmsg buffer and fill the provided buffer
+ * with as many of the *youngest* kmsg records that fit into it.
+ * If the buffer is large enough, all available kmsg records will be
+ * copied with a single call.
+ *
+ * Consecutive calls will fill the buffer with the next block of
+ * available older records, not including the earlier retrieved ones.
+ *
+ * A return value of FALSE indicates that there are no more records to
+ * read.
+ */
+bool kmsg_dump_get_buffer(struct kmsg_dump_iter *iter, bool syslog,
+			  char *buf, size_t size, size_t *len_out)
+{
+	u64 min_seq = latched_seq_read_nolock(&clear_seq);
+	struct printk_info info;
+	struct printk_record r;
+	u64 seq;
+	u64 next_seq;
+	size_t len = 0;
+	bool ret = false;
+	bool time = printk_time;
+
+	if (!buf || !size)
+		goto out;
+
+	if (iter->cur_seq < min_seq)
+		iter->cur_seq = min_seq;
+
+	if (prb_read_valid_info(prb, iter->cur_seq, &info, NULL)) {
+		if (info.seq != iter->cur_seq) {
+			/* messages are gone, move to first available one */
+			iter->cur_seq = info.seq;
+		}
+	}
+
+	/* last entry */
+	if (iter->cur_seq >= iter->next_seq)
+		goto out;
+
+	/*
+	 * Find first record that fits, including all following records,
+	 * into the user-provided buffer for this dump. Pass in size-1
+	 * because this function (by way of record_print_text()) will
+	 * not write more than size-1 bytes of text into @buf.
+	 */
+	seq = find_first_fitting_seq(iter->cur_seq, iter->next_seq,
+				     size - 1, syslog, time);
+
+	/*
+	 * Next kmsg_dump_get_buffer() invocation will dump block of
+	 * older records stored right before this one.
+	 */
+	next_seq = seq;
+
+	prb_rec_init_rd(&r, &info, buf, size);
+
+	len = 0;
+	prb_for_each_record(seq, prb, seq, &r) {
+		if (r.info->seq >= iter->next_seq)
+			break;
+
+		len += record_print_text(&r, syslog, time);
+
+		/* Adjust record to store to remaining buffer space. */
+		prb_rec_init_rd(&r, &info, buf + len, size - len);
+	}
+
+	iter->next_seq = next_seq;
+	ret = true;
+out:
+	if (len_out)
+		*len_out = len;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
+
+/**
+ * kmsg_dump_rewind - reset the iterator
+ * @iter: kmsg dump iterator
+ *
+ * Reset the dumper's iterator so that kmsg_dump_get_line() and
+ * kmsg_dump_get_buffer() can be called again and used multiple
+ * times within the same dumper.dump() callback.
+ */
+void kmsg_dump_rewind(struct kmsg_dump_iter *iter)
+{
+	iter->cur_seq = latched_seq_read_nolock(&clear_seq);
+	iter->next_seq = prb_next_seq(prb);
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
+
+#endif
+
+#ifdef CONFIG_SMP
+static atomic_t printk_cpu_sync_owner = ATOMIC_INIT(-1);
+static atomic_t printk_cpu_sync_nested = ATOMIC_INIT(0);
+
+/**
+ * __printk_cpu_sync_wait() - Busy wait until the printk cpu-reentrant
+ *                            spinning lock is not owned by any CPU.
+ *
+ * Context: Any context.
+ */
+void __printk_cpu_sync_wait(void)
+{
+	do {
+		cpu_relax();
+	} while (atomic_read(&printk_cpu_sync_owner) != -1);
+}
+EXPORT_SYMBOL(__printk_cpu_sync_wait);
+
+/**
+ * __printk_cpu_sync_try_get() - Try to acquire the printk cpu-reentrant
+ *                               spinning lock.
+ *
+ * If no processor has the lock, the calling processor takes the lock and
+ * becomes the owner. If the calling processor is already the owner of the
+ * lock, this function succeeds immediately.
+ *
+ * Context: Any context. Expects interrupts to be disabled.
+ * Return: 1 on success, otherwise 0.
+ */
+int __printk_cpu_sync_try_get(void)
+{
+	int cpu;
+	int old;
+
+	cpu = smp_processor_id();
+
+	/*
+	 * Guarantee loads and stores from this CPU when it is the lock owner
+	 * are _not_ visible to the previous lock owner. This pairs with
+	 * __printk_cpu_sync_put:B.
+	 *
+	 * Memory barrier involvement:
+	 *
+	 * If __printk_cpu_sync_try_get:A reads from __printk_cpu_sync_put:B,
+	 * then __printk_cpu_sync_put:A can never read from
+	 * __printk_cpu_sync_try_get:B.
+	 *
+	 * Relies on:
+	 *
+	 * RELEASE from __printk_cpu_sync_put:A to __printk_cpu_sync_put:B
+	 * of the previous CPU
+	 *    matching
+	 * ACQUIRE from __printk_cpu_sync_try_get:A to
+	 * __printk_cpu_sync_try_get:B of this CPU
+	 */
+	old = atomic_cmpxchg_acquire(&printk_cpu_sync_owner, -1,
+				     cpu); /* LMM(__printk_cpu_sync_try_get:A) */
+	if (old == -1) {
+		/*
+		 * This CPU is now the owner and begins loading/storing
+		 * data: LMM(__printk_cpu_sync_try_get:B)
+		 */
+		return 1;
+
+	} else if (old == cpu) {
+		/* This CPU is already the owner. */
+		atomic_inc(&printk_cpu_sync_nested);
+		return 1;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(__printk_cpu_sync_try_get);
+
+/**
+ * __printk_cpu_sync_put() - Release the printk cpu-reentrant spinning lock.
+ *
+ * The calling processor must be the owner of the lock.
+ *
+ * Context: Any context. Expects interrupts to be disabled.
+ */
+void __printk_cpu_sync_put(void)
+{
+	if (atomic_read(&printk_cpu_sync_nested)) {
+		atomic_dec(&printk_cpu_sync_nested);
+		return;
+	}
+
+	/*
+	 * This CPU is finished loading/storing data:
+	 * LMM(__printk_cpu_sync_put:A)
+	 */
+
+	/*
+	 * Guarantee loads and stores from this CPU when it was the
+	 * lock owner are visible to the next lock owner. This pairs
+	 * with __printk_cpu_sync_try_get:A.
+	 *
+	 * Memory barrier involvement:
+	 *
+	 * If __printk_cpu_sync_try_get:A reads from __printk_cpu_sync_put:B,
+	 * then __printk_cpu_sync_try_get:B reads from __printk_cpu_sync_put:A.
+	 *
+	 * Relies on:
+	 *
+	 * RELEASE from __printk_cpu_sync_put:A to __printk_cpu_sync_put:B
+	 * of this CPU
+	 *    matching
+	 * ACQUIRE from __printk_cpu_sync_try_get:A to
+	 * __printk_cpu_sync_try_get:B of the next CPU
+	 */
+	atomic_set_release(&printk_cpu_sync_owner,
+			   -1); /* LMM(__printk_cpu_sync_put:B) */
+}
+EXPORT_SYMBOL(__printk_cpu_sync_put);
+#endif /* CONFIG_SMP */
diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c
new file mode 100644
index 000000000..0bbcd1344
--- /dev/null
+++ b/kernel/printk/printk_ringbuffer.c
@@ -0,0 +1,2124 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/kernel.h>
+#include <linux/irqflags.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/bug.h>
+#include "printk_ringbuffer.h"
+
+/**
+ * DOC: printk_ringbuffer overview
+ *
+ * Data Structure
+ * --------------
+ * The printk_ringbuffer is made up of 3 internal ringbuffers:
+ *
+ *   desc_ring
+ *     A ring of descriptors and their meta data (such as sequence number,
+ *     timestamp, loglevel, etc.) as well as internal state information about
+ *     the record and logical positions specifying where in the other
+ *     ringbuffer the text strings are located.
+ *
+ *   text_data_ring
+ *     A ring of data blocks. A data block consists of an unsigned long
+ *     integer (ID) that maps to a desc_ring index followed by the text
+ *     string of the record.
+ *
+ * The internal state information of a descriptor is the key element to allow
+ * readers and writers to locklessly synchronize access to the data.
+ *
+ * Implementation
+ * --------------
+ *
+ * Descriptor Ring
+ * ~~~~~~~~~~~~~~~
+ * The descriptor ring is an array of descriptors. A descriptor contains
+ * essential meta data to track the data of a printk record using
+ * blk_lpos structs pointing to associated text data blocks (see
+ * "Data Rings" below). Each descriptor is assigned an ID that maps
+ * directly to index values of the descriptor array and has a state. The ID
+ * and the state are bitwise combined into a single descriptor field named
+ * @state_var, allowing ID and state to be synchronously and atomically
+ * updated.
+ *
+ * Descriptors have four states:
+ *
+ *   reserved
+ *     A writer is modifying the record.
+ *
+ *   committed
+ *     The record and all its data are written. A writer can reopen the
+ *     descriptor (transitioning it back to reserved), but in the committed
+ *     state the data is consistent.
+ *
+ *   finalized
+ *     The record and all its data are complete and available for reading. A
+ *     writer cannot reopen the descriptor.
+ *
+ *   reusable
+ *     The record exists, but its text and/or meta data may no longer be
+ *     available.
+ *
+ * Querying the @state_var of a record requires providing the ID of the
+ * descriptor to query. This can yield a possible fifth (pseudo) state:
+ *
+ *   miss
+ *     The descriptor being queried has an unexpected ID.
+ *
+ * The descriptor ring has a @tail_id that contains the ID of the oldest
+ * descriptor and @head_id that contains the ID of the newest descriptor.
+ *
+ * When a new descriptor should be created (and the ring is full), the tail
+ * descriptor is invalidated by first transitioning to the reusable state and
+ * then invalidating all tail data blocks up to and including the data blocks
+ * associated with the tail descriptor (for the text ring). Then
+ * @tail_id is advanced, followed by advancing @head_id. And finally the
+ * @state_var of the new descriptor is initialized to the new ID and reserved
+ * state.
+ *
+ * The @tail_id can only be advanced if the new @tail_id would be in the
+ * committed or reusable queried state. This makes it possible that a valid
+ * sequence number of the tail is always available.
+ *
+ * Descriptor Finalization
+ * ~~~~~~~~~~~~~~~~~~~~~~~
+ * When a writer calls the commit function prb_commit(), record data is
+ * fully stored and is consistent within the ringbuffer. However, a writer can
+ * reopen that record, claiming exclusive access (as with prb_reserve()), and
+ * modify that record. When finished, the writer must again commit the record.
+ *
+ * In order for a record to be made available to readers (and also become
+ * recyclable for writers), it must be finalized. A finalized record cannot be
+ * reopened and can never become "unfinalized". Record finalization can occur
+ * in three different scenarios:
+ *
+ *   1) A writer can simultaneously commit and finalize its record by calling
+ *      prb_final_commit() instead of prb_commit().
+ *
+ *   2) When a new record is reserved and the previous record has been
+ *      committed via prb_commit(), that previous record is automatically
+ *      finalized.
+ *
+ *   3) When a record is committed via prb_commit() and a newer record
+ *      already exists, the record being committed is automatically finalized.
+ *
+ * Data Ring
+ * ~~~~~~~~~
+ * The text data ring is a byte array composed of data blocks. Data blocks are
+ * referenced by blk_lpos structs that point to the logical position of the
+ * beginning of a data block and the beginning of the next adjacent data
+ * block. Logical positions are mapped directly to index values of the byte
+ * array ringbuffer.
+ *
+ * Each data block consists of an ID followed by the writer data. The ID is
+ * the identifier of a descriptor that is associated with the data block. A
+ * given data block is considered valid if all of the following conditions
+ * are met:
+ *
+ *   1) The descriptor associated with the data block is in the committed
+ *      or finalized queried state.
+ *
+ *   2) The blk_lpos struct within the descriptor associated with the data
+ *      block references back to the same data block.
+ *
+ *   3) The data block is within the head/tail logical position range.
+ *
+ * If the writer data of a data block would extend beyond the end of the
+ * byte array, only the ID of the data block is stored at the logical
+ * position and the full data block (ID and writer data) is stored at the
+ * beginning of the byte array. The referencing blk_lpos will point to the
+ * ID before the wrap and the next data block will be at the logical
+ * position adjacent the full data block after the wrap.
+ *
+ * Data rings have a @tail_lpos that points to the beginning of the oldest
+ * data block and a @head_lpos that points to the logical position of the
+ * next (not yet existing) data block.
+ *
+ * When a new data block should be created (and the ring is full), tail data
+ * blocks will first be invalidated by putting their associated descriptors
+ * into the reusable state and then pushing the @tail_lpos forward beyond
+ * them. Then the @head_lpos is pushed forward and is associated with a new
+ * descriptor. If a data block is not valid, the @tail_lpos cannot be
+ * advanced beyond it.
+ *
+ * Info Array
+ * ~~~~~~~~~~
+ * The general meta data of printk records are stored in printk_info structs,
+ * stored in an array with the same number of elements as the descriptor ring.
+ * Each info corresponds to the descriptor of the same index in the
+ * descriptor ring. Info validity is confirmed by evaluating the corresponding
+ * descriptor before and after loading the info.
+ *
+ * Usage
+ * -----
+ * Here are some simple examples demonstrating writers and readers. For the
+ * examples a global ringbuffer (test_rb) is available (which is not the
+ * actual ringbuffer used by printk)::
+ *
+ *	DEFINE_PRINTKRB(test_rb, 15, 5);
+ *
+ * This ringbuffer allows up to 32768 records (2 ^ 15) and has a size of
+ * 1 MiB (2 ^ (15 + 5)) for text data.
+ *
+ * Sample writer code::
+ *
+ *	const char *textstr = "message text";
+ *	struct prb_reserved_entry e;
+ *	struct printk_record r;
+ *
+ *	// specify how much to allocate
+ *	prb_rec_init_wr(&r, strlen(textstr) + 1);
+ *
+ *	if (prb_reserve(&e, &test_rb, &r)) {
+ *		snprintf(r.text_buf, r.text_buf_size, "%s", textstr);
+ *
+ *		r.info->text_len = strlen(textstr);
+ *		r.info->ts_nsec = local_clock();
+ *		r.info->caller_id = printk_caller_id();
+ *
+ *		// commit and finalize the record
+ *		prb_final_commit(&e);
+ *	}
+ *
+ * Note that additional writer functions are available to extend a record
+ * after it has been committed but not yet finalized. This can be done as
+ * long as no new records have been reserved and the caller is the same.
+ *
+ * Sample writer code (record extending)::
+ *
+ *		// alternate rest of previous example
+ *
+ *		r.info->text_len = strlen(textstr);
+ *		r.info->ts_nsec = local_clock();
+ *		r.info->caller_id = printk_caller_id();
+ *
+ *		// commit the record (but do not finalize yet)
+ *		prb_commit(&e);
+ *	}
+ *
+ *	...
+ *
+ *	// specify additional 5 bytes text space to extend
+ *	prb_rec_init_wr(&r, 5);
+ *
+ *	// try to extend, but only if it does not exceed 32 bytes
+ *	if (prb_reserve_in_last(&e, &test_rb, &r, printk_caller_id()), 32) {
+ *		snprintf(&r.text_buf[r.info->text_len],
+ *			 r.text_buf_size - r.info->text_len, "hello");
+ *
+ *		r.info->text_len += 5;
+ *
+ *		// commit and finalize the record
+ *		prb_final_commit(&e);
+ *	}
+ *
+ * Sample reader code::
+ *
+ *	struct printk_info info;
+ *	struct printk_record r;
+ *	char text_buf[32];
+ *	u64 seq;
+ *
+ *	prb_rec_init_rd(&r, &info, &text_buf[0], sizeof(text_buf));
+ *
+ *	prb_for_each_record(0, &test_rb, &seq, &r) {
+ *		if (info.seq != seq)
+ *			pr_warn("lost %llu records\n", info.seq - seq);
+ *
+ *		if (info.text_len > r.text_buf_size) {
+ *			pr_warn("record %llu text truncated\n", info.seq);
+ *			text_buf[r.text_buf_size - 1] = 0;
+ *		}
+ *
+ *		pr_info("%llu: %llu: %s\n", info.seq, info.ts_nsec,
+ *			&text_buf[0]);
+ *	}
+ *
+ * Note that additional less convenient reader functions are available to
+ * allow complex record access.
+ *
+ * ABA Issues
+ * ~~~~~~~~~~
+ * To help avoid ABA issues, descriptors are referenced by IDs (array index
+ * values combined with tagged bits counting array wraps) and data blocks are
+ * referenced by logical positions (array index values combined with tagged
+ * bits counting array wraps). However, on 32-bit systems the number of
+ * tagged bits is relatively small such that an ABA incident is (at least
+ * theoretically) possible. For example, if 4 million maximally sized (1KiB)
+ * printk messages were to occur in NMI context on a 32-bit system, the
+ * interrupted context would not be able to recognize that the 32-bit integer
+ * completely wrapped and thus represents a different data block than the one
+ * the interrupted context expects.
+ *
+ * To help combat this possibility, additional state checking is performed
+ * (such as using cmpxchg() even though set() would suffice). These extra
+ * checks are commented as such and will hopefully catch any ABA issue that
+ * a 32-bit system might experience.
+ *
+ * Memory Barriers
+ * ~~~~~~~~~~~~~~~
+ * Multiple memory barriers are used. To simplify proving correctness and
+ * generating litmus tests, lines of code related to memory barriers
+ * (loads, stores, and the associated memory barriers) are labeled::
+ *
+ *	LMM(function:letter)
+ *
+ * Comments reference the labels using only the "function:letter" part.
+ *
+ * The memory barrier pairs and their ordering are:
+ *
+ *   desc_reserve:D / desc_reserve:B
+ *     push descriptor tail (id), then push descriptor head (id)
+ *
+ *   desc_reserve:D / data_push_tail:B
+ *     push data tail (lpos), then set new descriptor reserved (state)
+ *
+ *   desc_reserve:D / desc_push_tail:C
+ *     push descriptor tail (id), then set new descriptor reserved (state)
+ *
+ *   desc_reserve:D / prb_first_seq:C
+ *     push descriptor tail (id), then set new descriptor reserved (state)
+ *
+ *   desc_reserve:F / desc_read:D
+ *     set new descriptor id and reserved (state), then allow writer changes
+ *
+ *   data_alloc:A (or data_realloc:A) / desc_read:D
+ *     set old descriptor reusable (state), then modify new data block area
+ *
+ *   data_alloc:A (or data_realloc:A) / data_push_tail:B
+ *     push data tail (lpos), then modify new data block area
+ *
+ *   _prb_commit:B / desc_read:B
+ *     store writer changes, then set new descriptor committed (state)
+ *
+ *   desc_reopen_last:A / _prb_commit:B
+ *     set descriptor reserved (state), then read descriptor data
+ *
+ *   _prb_commit:B / desc_reserve:D
+ *     set new descriptor committed (state), then check descriptor head (id)
+ *
+ *   data_push_tail:D / data_push_tail:A
+ *     set descriptor reusable (state), then push data tail (lpos)
+ *
+ *   desc_push_tail:B / desc_reserve:D
+ *     set descriptor reusable (state), then push descriptor tail (id)
+ */
+
+#define DATA_SIZE(data_ring)		_DATA_SIZE((data_ring)->size_bits)
+#define DATA_SIZE_MASK(data_ring)	(DATA_SIZE(data_ring) - 1)
+
+#define DESCS_COUNT(desc_ring)		_DESCS_COUNT((desc_ring)->count_bits)
+#define DESCS_COUNT_MASK(desc_ring)	(DESCS_COUNT(desc_ring) - 1)
+
+/* Determine the data array index from a logical position. */
+#define DATA_INDEX(data_ring, lpos)	((lpos) & DATA_SIZE_MASK(data_ring))
+
+/* Determine the desc array index from an ID or sequence number. */
+#define DESC_INDEX(desc_ring, n)	((n) & DESCS_COUNT_MASK(desc_ring))
+
+/* Determine how many times the data array has wrapped. */
+#define DATA_WRAPS(data_ring, lpos)	((lpos) >> (data_ring)->size_bits)
+
+/* Determine if a logical position refers to a data-less block. */
+#define LPOS_DATALESS(lpos)		((lpos) & 1UL)
+#define BLK_DATALESS(blk)		(LPOS_DATALESS((blk)->begin) && \
+					 LPOS_DATALESS((blk)->next))
+
+/* Get the logical position at index 0 of the current wrap. */
+#define DATA_THIS_WRAP_START_LPOS(data_ring, lpos) \
+((lpos) & ~DATA_SIZE_MASK(data_ring))
+
+/* Get the ID for the same index of the previous wrap as the given ID. */
+#define DESC_ID_PREV_WRAP(desc_ring, id) \
+DESC_ID((id) - DESCS_COUNT(desc_ring))
+
+/*
+ * A data block: mapped directly to the beginning of the data block area
+ * specified as a logical position within the data ring.
+ *
+ * @id:   the ID of the associated descriptor
+ * @data: the writer data
+ *
+ * Note that the size of a data block is only known by its associated
+ * descriptor.
+ */
+struct prb_data_block {
+	unsigned long	id;
+	char		data[];
+};
+
+/*
+ * Return the descriptor associated with @n. @n can be either a
+ * descriptor ID or a sequence number.
+ */
+static struct prb_desc *to_desc(struct prb_desc_ring *desc_ring, u64 n)
+{
+	return &desc_ring->descs[DESC_INDEX(desc_ring, n)];
+}
+
+/*
+ * Return the printk_info associated with @n. @n can be either a
+ * descriptor ID or a sequence number.
+ */
+static struct printk_info *to_info(struct prb_desc_ring *desc_ring, u64 n)
+{
+	return &desc_ring->infos[DESC_INDEX(desc_ring, n)];
+}
+
+static struct prb_data_block *to_block(struct prb_data_ring *data_ring,
+				       unsigned long begin_lpos)
+{
+	return (void *)&data_ring->data[DATA_INDEX(data_ring, begin_lpos)];
+}
+
+/*
+ * Increase the data size to account for data block meta data plus any
+ * padding so that the adjacent data block is aligned on the ID size.
+ */
+static unsigned int to_blk_size(unsigned int size)
+{
+	struct prb_data_block *db = NULL;
+
+	size += sizeof(*db);
+	size = ALIGN(size, sizeof(db->id));
+	return size;
+}
+
+/*
+ * Sanity checker for reserve size. The ringbuffer code assumes that a data
+ * block does not exceed the maximum possible size that could fit within the
+ * ringbuffer. This function provides that basic size check so that the
+ * assumption is safe.
+ */
+static bool data_check_size(struct prb_data_ring *data_ring, unsigned int size)
+{
+	struct prb_data_block *db = NULL;
+
+	if (size == 0)
+		return true;
+
+	/*
+	 * Ensure the alignment padded size could possibly fit in the data
+	 * array. The largest possible data block must still leave room for
+	 * at least the ID of the next block.
+	 */
+	size = to_blk_size(size);
+	if (size > DATA_SIZE(data_ring) - sizeof(db->id))
+		return false;
+
+	return true;
+}
+
+/* Query the state of a descriptor. */
+static enum desc_state get_desc_state(unsigned long id,
+				      unsigned long state_val)
+{
+	if (id != DESC_ID(state_val))
+		return desc_miss;
+
+	return DESC_STATE(state_val);
+}
+
+/*
+ * Get a copy of a specified descriptor and return its queried state. If the
+ * descriptor is in an inconsistent state (miss or reserved), the caller can
+ * only expect the descriptor's @state_var field to be valid.
+ *
+ * The sequence number and caller_id can be optionally retrieved. Like all
+ * non-state_var data, they are only valid if the descriptor is in a
+ * consistent state.
+ */
+static enum desc_state desc_read(struct prb_desc_ring *desc_ring,
+				 unsigned long id, struct prb_desc *desc_out,
+				 u64 *seq_out, u32 *caller_id_out)
+{
+	struct printk_info *info = to_info(desc_ring, id);
+	struct prb_desc *desc = to_desc(desc_ring, id);
+	atomic_long_t *state_var = &desc->state_var;
+	enum desc_state d_state;
+	unsigned long state_val;
+
+	/* Check the descriptor state. */
+	state_val = atomic_long_read(state_var); /* LMM(desc_read:A) */
+	d_state = get_desc_state(id, state_val);
+	if (d_state == desc_miss || d_state == desc_reserved) {
+		/*
+		 * The descriptor is in an inconsistent state. Set at least
+		 * @state_var so that the caller can see the details of
+		 * the inconsistent state.
+		 */
+		goto out;
+	}
+
+	/*
+	 * Guarantee the state is loaded before copying the descriptor
+	 * content. This avoids copying obsolete descriptor content that might
+	 * not apply to the descriptor state. This pairs with _prb_commit:B.
+	 *
+	 * Memory barrier involvement:
+	 *
+	 * If desc_read:A reads from _prb_commit:B, then desc_read:C reads
+	 * from _prb_commit:A.
+	 *
+	 * Relies on:
+	 *
+	 * WMB from _prb_commit:A to _prb_commit:B
+	 *    matching
+	 * RMB from desc_read:A to desc_read:C
+	 */
+	smp_rmb(); /* LMM(desc_read:B) */
+
+	/*
+	 * Copy the descriptor data. The data is not valid until the
+	 * state has been re-checked. A memcpy() for all of @desc
+	 * cannot be used because of the atomic_t @state_var field.
+	 */
+	if (desc_out) {
+		memcpy(&desc_out->text_blk_lpos, &desc->text_blk_lpos,
+		       sizeof(desc_out->text_blk_lpos)); /* LMM(desc_read:C) */
+	}
+	if (seq_out)
+		*seq_out = info->seq; /* also part of desc_read:C */
+	if (caller_id_out)
+		*caller_id_out = info->caller_id; /* also part of desc_read:C */
+
+	/*
+	 * 1. Guarantee the descriptor content is loaded before re-checking
+	 *    the state. This avoids reading an obsolete descriptor state
+	 *    that may not apply to the copied content. This pairs with
+	 *    desc_reserve:F.
+	 *
+	 *    Memory barrier involvement:
+	 *
+	 *    If desc_read:C reads from desc_reserve:G, then desc_read:E
+	 *    reads from desc_reserve:F.
+	 *
+	 *    Relies on:
+	 *
+	 *    WMB from desc_reserve:F to desc_reserve:G
+	 *       matching
+	 *    RMB from desc_read:C to desc_read:E
+	 *
+	 * 2. Guarantee the record data is loaded before re-checking the
+	 *    state. This avoids reading an obsolete descriptor state that may
+	 *    not apply to the copied data. This pairs with data_alloc:A and
+	 *    data_realloc:A.
+	 *
+	 *    Memory barrier involvement:
+	 *
+	 *    If copy_data:A reads from data_alloc:B, then desc_read:E
+	 *    reads from desc_make_reusable:A.
+	 *
+	 *    Relies on:
+	 *
+	 *    MB from desc_make_reusable:A to data_alloc:B
+	 *       matching
+	 *    RMB from desc_read:C to desc_read:E
+	 *
+	 *    Note: desc_make_reusable:A and data_alloc:B can be different
+	 *          CPUs. However, the data_alloc:B CPU (which performs the
+	 *          full memory barrier) must have previously seen
+	 *          desc_make_reusable:A.
+	 */
+	smp_rmb(); /* LMM(desc_read:D) */
+
+	/*
+	 * The data has been copied. Return the current descriptor state,
+	 * which may have changed since the load above.
+	 */
+	state_val = atomic_long_read(state_var); /* LMM(desc_read:E) */
+	d_state = get_desc_state(id, state_val);
+out:
+	if (desc_out)
+		atomic_long_set(&desc_out->state_var, state_val);
+	return d_state;
+}
+
+/*
+ * Take a specified descriptor out of the finalized state by attempting
+ * the transition from finalized to reusable. Either this context or some
+ * other context will have been successful.
+ */
+static void desc_make_reusable(struct prb_desc_ring *desc_ring,
+			       unsigned long id)
+{
+	unsigned long val_finalized = DESC_SV(id, desc_finalized);
+	unsigned long val_reusable = DESC_SV(id, desc_reusable);
+	struct prb_desc *desc = to_desc(desc_ring, id);
+	atomic_long_t *state_var = &desc->state_var;
+
+	atomic_long_cmpxchg_relaxed(state_var, val_finalized,
+				    val_reusable); /* LMM(desc_make_reusable:A) */
+}
+
+/*
+ * Given the text data ring, put the associated descriptor of each
+ * data block from @lpos_begin until @lpos_end into the reusable state.
+ *
+ * If there is any problem making the associated descriptor reusable, either
+ * the descriptor has not yet been finalized or another writer context has
+ * already pushed the tail lpos past the problematic data block. Regardless,
+ * on error the caller can re-load the tail lpos to determine the situation.
+ */
+static bool data_make_reusable(struct printk_ringbuffer *rb,
+			       unsigned long lpos_begin,
+			       unsigned long lpos_end,
+			       unsigned long *lpos_out)
+{
+
+	struct prb_data_ring *data_ring = &rb->text_data_ring;
+	struct prb_desc_ring *desc_ring = &rb->desc_ring;
+	struct prb_data_block *blk;
+	enum desc_state d_state;
+	struct prb_desc desc;
+	struct prb_data_blk_lpos *blk_lpos = &desc.text_blk_lpos;
+	unsigned long id;
+
+	/* Loop until @lpos_begin has advanced to or beyond @lpos_end. */
+	while ((lpos_end - lpos_begin) - 1 < DATA_SIZE(data_ring)) {
+		blk = to_block(data_ring, lpos_begin);
+
+		/*
+		 * Load the block ID from the data block. This is a data race
+		 * against a writer that may have newly reserved this data
+		 * area. If the loaded value matches a valid descriptor ID,
+		 * the blk_lpos of that descriptor will be checked to make
+		 * sure it points back to this data block. If the check fails,
+		 * the data area has been recycled by another writer.
+		 */
+		id = blk->id; /* LMM(data_make_reusable:A) */
+
+		d_state = desc_read(desc_ring, id, &desc,
+				    NULL, NULL); /* LMM(data_make_reusable:B) */
+
+		switch (d_state) {
+		case desc_miss:
+		case desc_reserved:
+		case desc_committed:
+			return false;
+		case desc_finalized:
+			/*
+			 * This data block is invalid if the descriptor
+			 * does not point back to it.
+			 */
+			if (blk_lpos->begin != lpos_begin)
+				return false;
+			desc_make_reusable(desc_ring, id);
+			break;
+		case desc_reusable:
+			/*
+			 * This data block is invalid if the descriptor
+			 * does not point back to it.
+			 */
+			if (blk_lpos->begin != lpos_begin)
+				return false;
+			break;
+		}
+
+		/* Advance @lpos_begin to the next data block. */
+		lpos_begin = blk_lpos->next;
+	}
+
+	*lpos_out = lpos_begin;
+	return true;
+}
+
+/*
+ * Advance the data ring tail to at least @lpos. This function puts
+ * descriptors into the reusable state if the tail is pushed beyond
+ * their associated data block.
+ */
+static bool data_push_tail(struct printk_ringbuffer *rb, unsigned long lpos)
+{
+	struct prb_data_ring *data_ring = &rb->text_data_ring;
+	unsigned long tail_lpos_new;
+	unsigned long tail_lpos;
+	unsigned long next_lpos;
+
+	/* If @lpos is from a data-less block, there is nothing to do. */
+	if (LPOS_DATALESS(lpos))
+		return true;
+
+	/*
+	 * Any descriptor states that have transitioned to reusable due to the
+	 * data tail being pushed to this loaded value will be visible to this
+	 * CPU. This pairs with data_push_tail:D.
+	 *
+	 * Memory barrier involvement:
+	 *
+	 * If data_push_tail:A reads from data_push_tail:D, then this CPU can
+	 * see desc_make_reusable:A.
+	 *
+	 * Relies on:
+	 *
+	 * MB from desc_make_reusable:A to data_push_tail:D
+	 *    matches
+	 * READFROM from data_push_tail:D to data_push_tail:A
+	 *    thus
+	 * READFROM from desc_make_reusable:A to this CPU
+	 */
+	tail_lpos = atomic_long_read(&data_ring->tail_lpos); /* LMM(data_push_tail:A) */
+
+	/*
+	 * Loop until the tail lpos is at or beyond @lpos. This condition
+	 * may already be satisfied, resulting in no full memory barrier
+	 * from data_push_tail:D being performed. However, since this CPU
+	 * sees the new tail lpos, any descriptor states that transitioned to
+	 * the reusable state must already be visible.
+	 */
+	while ((lpos - tail_lpos) - 1 < DATA_SIZE(data_ring)) {
+		/*
+		 * Make all descriptors reusable that are associated with
+		 * data blocks before @lpos.
+		 */
+		if (!data_make_reusable(rb, tail_lpos, lpos, &next_lpos)) {
+			/*
+			 * 1. Guarantee the block ID loaded in
+			 *    data_make_reusable() is performed before
+			 *    reloading the tail lpos. The failed
+			 *    data_make_reusable() may be due to a newly
+			 *    recycled data area causing the tail lpos to
+			 *    have been previously pushed. This pairs with
+			 *    data_alloc:A and data_realloc:A.
+			 *
+			 *    Memory barrier involvement:
+			 *
+			 *    If data_make_reusable:A reads from data_alloc:B,
+			 *    then data_push_tail:C reads from
+			 *    data_push_tail:D.
+			 *
+			 *    Relies on:
+			 *
+			 *    MB from data_push_tail:D to data_alloc:B
+			 *       matching
+			 *    RMB from data_make_reusable:A to
+			 *    data_push_tail:C
+			 *
+			 *    Note: data_push_tail:D and data_alloc:B can be
+			 *          different CPUs. However, the data_alloc:B
+			 *          CPU (which performs the full memory
+			 *          barrier) must have previously seen
+			 *          data_push_tail:D.
+			 *
+			 * 2. Guarantee the descriptor state loaded in
+			 *    data_make_reusable() is performed before
+			 *    reloading the tail lpos. The failed
+			 *    data_make_reusable() may be due to a newly
+			 *    recycled descriptor causing the tail lpos to
+			 *    have been previously pushed. This pairs with
+			 *    desc_reserve:D.
+			 *
+			 *    Memory barrier involvement:
+			 *
+			 *    If data_make_reusable:B reads from
+			 *    desc_reserve:F, then data_push_tail:C reads
+			 *    from data_push_tail:D.
+			 *
+			 *    Relies on:
+			 *
+			 *    MB from data_push_tail:D to desc_reserve:F
+			 *       matching
+			 *    RMB from data_make_reusable:B to
+			 *    data_push_tail:C
+			 *
+			 *    Note: data_push_tail:D and desc_reserve:F can
+			 *          be different CPUs. However, the
+			 *          desc_reserve:F CPU (which performs the
+			 *          full memory barrier) must have previously
+			 *          seen data_push_tail:D.
+			 */
+			smp_rmb(); /* LMM(data_push_tail:B) */
+
+			tail_lpos_new = atomic_long_read(&data_ring->tail_lpos
+							); /* LMM(data_push_tail:C) */
+			if (tail_lpos_new == tail_lpos)
+				return false;
+
+			/* Another CPU pushed the tail. Try again. */
+			tail_lpos = tail_lpos_new;
+			continue;
+		}
+
+		/*
+		 * Guarantee any descriptor states that have transitioned to
+		 * reusable are stored before pushing the tail lpos. A full
+		 * memory barrier is needed since other CPUs may have made
+		 * the descriptor states reusable. This pairs with
+		 * data_push_tail:A.
+		 */
+		if (atomic_long_try_cmpxchg(&data_ring->tail_lpos, &tail_lpos,
+					    next_lpos)) { /* LMM(data_push_tail:D) */
+			break;
+		}
+	}
+
+	return true;
+}
+
+/*
+ * Advance the desc ring tail. This function advances the tail by one
+ * descriptor, thus invalidating the oldest descriptor. Before advancing
+ * the tail, the tail descriptor is made reusable and all data blocks up to
+ * and including the descriptor's data block are invalidated (i.e. the data
+ * ring tail is pushed past the data block of the descriptor being made
+ * reusable).
+ */
+static bool desc_push_tail(struct printk_ringbuffer *rb,
+			   unsigned long tail_id)
+{
+	struct prb_desc_ring *desc_ring = &rb->desc_ring;
+	enum desc_state d_state;
+	struct prb_desc desc;
+
+	d_state = desc_read(desc_ring, tail_id, &desc, NULL, NULL);
+
+	switch (d_state) {
+	case desc_miss:
+		/*
+		 * If the ID is exactly 1 wrap behind the expected, it is
+		 * in the process of being reserved by another writer and
+		 * must be considered reserved.
+		 */
+		if (DESC_ID(atomic_long_read(&desc.state_var)) ==
+		    DESC_ID_PREV_WRAP(desc_ring, tail_id)) {
+			return false;
+		}
+
+		/*
+		 * The ID has changed. Another writer must have pushed the
+		 * tail and recycled the descriptor already. Success is
+		 * returned because the caller is only interested in the
+		 * specified tail being pushed, which it was.
+		 */
+		return true;
+	case desc_reserved:
+	case desc_committed:
+		return false;
+	case desc_finalized:
+		desc_make_reusable(desc_ring, tail_id);
+		break;
+	case desc_reusable:
+		break;
+	}
+
+	/*
+	 * Data blocks must be invalidated before their associated
+	 * descriptor can be made available for recycling. Invalidating
+	 * them later is not possible because there is no way to trust
+	 * data blocks once their associated descriptor is gone.
+	 */
+
+	if (!data_push_tail(rb, desc.text_blk_lpos.next))
+		return false;
+
+	/*
+	 * Check the next descriptor after @tail_id before pushing the tail
+	 * to it because the tail must always be in a finalized or reusable
+	 * state. The implementation of prb_first_seq() relies on this.
+	 *
+	 * A successful read implies that the next descriptor is less than or
+	 * equal to @head_id so there is no risk of pushing the tail past the
+	 * head.
+	 */
+	d_state = desc_read(desc_ring, DESC_ID(tail_id + 1), &desc,
+			    NULL, NULL); /* LMM(desc_push_tail:A) */
+
+	if (d_state == desc_finalized || d_state == desc_reusable) {
+		/*
+		 * Guarantee any descriptor states that have transitioned to
+		 * reusable are stored before pushing the tail ID. This allows
+		 * verifying the recycled descriptor state. A full memory
+		 * barrier is needed since other CPUs may have made the
+		 * descriptor states reusable. This pairs with desc_reserve:D.
+		 */
+		atomic_long_cmpxchg(&desc_ring->tail_id, tail_id,
+				    DESC_ID(tail_id + 1)); /* LMM(desc_push_tail:B) */
+	} else {
+		/*
+		 * Guarantee the last state load from desc_read() is before
+		 * reloading @tail_id in order to see a new tail ID in the
+		 * case that the descriptor has been recycled. This pairs
+		 * with desc_reserve:D.
+		 *
+		 * Memory barrier involvement:
+		 *
+		 * If desc_push_tail:A reads from desc_reserve:F, then
+		 * desc_push_tail:D reads from desc_push_tail:B.
+		 *
+		 * Relies on:
+		 *
+		 * MB from desc_push_tail:B to desc_reserve:F
+		 *    matching
+		 * RMB from desc_push_tail:A to desc_push_tail:D
+		 *
+		 * Note: desc_push_tail:B and desc_reserve:F can be different
+		 *       CPUs. However, the desc_reserve:F CPU (which performs
+		 *       the full memory barrier) must have previously seen
+		 *       desc_push_tail:B.
+		 */
+		smp_rmb(); /* LMM(desc_push_tail:C) */
+
+		/*
+		 * Re-check the tail ID. The descriptor following @tail_id is
+		 * not in an allowed tail state. But if the tail has since
+		 * been moved by another CPU, then it does not matter.
+		 */
+		if (atomic_long_read(&desc_ring->tail_id) == tail_id) /* LMM(desc_push_tail:D) */
+			return false;
+	}
+
+	return true;
+}
+
+/* Reserve a new descriptor, invalidating the oldest if necessary. */
+static bool desc_reserve(struct printk_ringbuffer *rb, unsigned long *id_out)
+{
+	struct prb_desc_ring *desc_ring = &rb->desc_ring;
+	unsigned long prev_state_val;
+	unsigned long id_prev_wrap;
+	struct prb_desc *desc;
+	unsigned long head_id;
+	unsigned long id;
+
+	head_id = atomic_long_read(&desc_ring->head_id); /* LMM(desc_reserve:A) */
+
+	do {
+		id = DESC_ID(head_id + 1);
+		id_prev_wrap = DESC_ID_PREV_WRAP(desc_ring, id);
+
+		/*
+		 * Guarantee the head ID is read before reading the tail ID.
+		 * Since the tail ID is updated before the head ID, this
+		 * guarantees that @id_prev_wrap is never ahead of the tail
+		 * ID. This pairs with desc_reserve:D.
+		 *
+		 * Memory barrier involvement:
+		 *
+		 * If desc_reserve:A reads from desc_reserve:D, then
+		 * desc_reserve:C reads from desc_push_tail:B.
+		 *
+		 * Relies on:
+		 *
+		 * MB from desc_push_tail:B to desc_reserve:D
+		 *    matching
+		 * RMB from desc_reserve:A to desc_reserve:C
+		 *
+		 * Note: desc_push_tail:B and desc_reserve:D can be different
+		 *       CPUs. However, the desc_reserve:D CPU (which performs
+		 *       the full memory barrier) must have previously seen
+		 *       desc_push_tail:B.
+		 */
+		smp_rmb(); /* LMM(desc_reserve:B) */
+
+		if (id_prev_wrap == atomic_long_read(&desc_ring->tail_id
+						    )) { /* LMM(desc_reserve:C) */
+			/*
+			 * Make space for the new descriptor by
+			 * advancing the tail.
+			 */
+			if (!desc_push_tail(rb, id_prev_wrap))
+				return false;
+		}
+
+		/*
+		 * 1. Guarantee the tail ID is read before validating the
+		 *    recycled descriptor state. A read memory barrier is
+		 *    sufficient for this. This pairs with desc_push_tail:B.
+		 *
+		 *    Memory barrier involvement:
+		 *
+		 *    If desc_reserve:C reads from desc_push_tail:B, then
+		 *    desc_reserve:E reads from desc_make_reusable:A.
+		 *
+		 *    Relies on:
+		 *
+		 *    MB from desc_make_reusable:A to desc_push_tail:B
+		 *       matching
+		 *    RMB from desc_reserve:C to desc_reserve:E
+		 *
+		 *    Note: desc_make_reusable:A and desc_push_tail:B can be
+		 *          different CPUs. However, the desc_push_tail:B CPU
+		 *          (which performs the full memory barrier) must have
+		 *          previously seen desc_make_reusable:A.
+		 *
+		 * 2. Guarantee the tail ID is stored before storing the head
+		 *    ID. This pairs with desc_reserve:B.
+		 *
+		 * 3. Guarantee any data ring tail changes are stored before
+		 *    recycling the descriptor. Data ring tail changes can
+		 *    happen via desc_push_tail()->data_push_tail(). A full
+		 *    memory barrier is needed since another CPU may have
+		 *    pushed the data ring tails. This pairs with
+		 *    data_push_tail:B.
+		 *
+		 * 4. Guarantee a new tail ID is stored before recycling the
+		 *    descriptor. A full memory barrier is needed since
+		 *    another CPU may have pushed the tail ID. This pairs
+		 *    with desc_push_tail:C and this also pairs with
+		 *    prb_first_seq:C.
+		 *
+		 * 5. Guarantee the head ID is stored before trying to
+		 *    finalize the previous descriptor. This pairs with
+		 *    _prb_commit:B.
+		 */
+	} while (!atomic_long_try_cmpxchg(&desc_ring->head_id, &head_id,
+					  id)); /* LMM(desc_reserve:D) */
+
+	desc = to_desc(desc_ring, id);
+
+	/*
+	 * If the descriptor has been recycled, verify the old state val.
+	 * See "ABA Issues" about why this verification is performed.
+	 */
+	prev_state_val = atomic_long_read(&desc->state_var); /* LMM(desc_reserve:E) */
+	if (prev_state_val &&
+	    get_desc_state(id_prev_wrap, prev_state_val) != desc_reusable) {
+		WARN_ON_ONCE(1);
+		return false;
+	}
+
+	/*
+	 * Assign the descriptor a new ID and set its state to reserved.
+	 * See "ABA Issues" about why cmpxchg() instead of set() is used.
+	 *
+	 * Guarantee the new descriptor ID and state is stored before making
+	 * any other changes. A write memory barrier is sufficient for this.
+	 * This pairs with desc_read:D.
+	 */
+	if (!atomic_long_try_cmpxchg(&desc->state_var, &prev_state_val,
+			DESC_SV(id, desc_reserved))) { /* LMM(desc_reserve:F) */
+		WARN_ON_ONCE(1);
+		return false;
+	}
+
+	/* Now data in @desc can be modified: LMM(desc_reserve:G) */
+
+	*id_out = id;
+	return true;
+}
+
+/* Determine the end of a data block. */
+static unsigned long get_next_lpos(struct prb_data_ring *data_ring,
+				   unsigned long lpos, unsigned int size)
+{
+	unsigned long begin_lpos;
+	unsigned long next_lpos;
+
+	begin_lpos = lpos;
+	next_lpos = lpos + size;
+
+	/* First check if the data block does not wrap. */
+	if (DATA_WRAPS(data_ring, begin_lpos) == DATA_WRAPS(data_ring, next_lpos))
+		return next_lpos;
+
+	/* Wrapping data blocks store their data at the beginning. */
+	return (DATA_THIS_WRAP_START_LPOS(data_ring, next_lpos) + size);
+}
+
+/*
+ * Allocate a new data block, invalidating the oldest data block(s)
+ * if necessary. This function also associates the data block with
+ * a specified descriptor.
+ */
+static char *data_alloc(struct printk_ringbuffer *rb, unsigned int size,
+			struct prb_data_blk_lpos *blk_lpos, unsigned long id)
+{
+	struct prb_data_ring *data_ring = &rb->text_data_ring;
+	struct prb_data_block *blk;
+	unsigned long begin_lpos;
+	unsigned long next_lpos;
+
+	if (size == 0) {
+		/* Specify a data-less block. */
+		blk_lpos->begin = NO_LPOS;
+		blk_lpos->next = NO_LPOS;
+		return NULL;
+	}
+
+	size = to_blk_size(size);
+
+	begin_lpos = atomic_long_read(&data_ring->head_lpos);
+
+	do {
+		next_lpos = get_next_lpos(data_ring, begin_lpos, size);
+
+		if (!data_push_tail(rb, next_lpos - DATA_SIZE(data_ring))) {
+			/* Failed to allocate, specify a data-less block. */
+			blk_lpos->begin = FAILED_LPOS;
+			blk_lpos->next = FAILED_LPOS;
+			return NULL;
+		}
+
+		/*
+		 * 1. Guarantee any descriptor states that have transitioned
+		 *    to reusable are stored before modifying the newly
+		 *    allocated data area. A full memory barrier is needed
+		 *    since other CPUs may have made the descriptor states
+		 *    reusable. See data_push_tail:A about why the reusable
+		 *    states are visible. This pairs with desc_read:D.
+		 *
+		 * 2. Guarantee any updated tail lpos is stored before
+		 *    modifying the newly allocated data area. Another CPU may
+		 *    be in data_make_reusable() and is reading a block ID
+		 *    from this area. data_make_reusable() can handle reading
+		 *    a garbage block ID value, but then it must be able to
+		 *    load a new tail lpos. A full memory barrier is needed
+		 *    since other CPUs may have updated the tail lpos. This
+		 *    pairs with data_push_tail:B.
+		 */
+	} while (!atomic_long_try_cmpxchg(&data_ring->head_lpos, &begin_lpos,
+					  next_lpos)); /* LMM(data_alloc:A) */
+
+	blk = to_block(data_ring, begin_lpos);
+	blk->id = id; /* LMM(data_alloc:B) */
+
+	if (DATA_WRAPS(data_ring, begin_lpos) != DATA_WRAPS(data_ring, next_lpos)) {
+		/* Wrapping data blocks store their data at the beginning. */
+		blk = to_block(data_ring, 0);
+
+		/*
+		 * Store the ID on the wrapped block for consistency.
+		 * The printk_ringbuffer does not actually use it.
+		 */
+		blk->id = id;
+	}
+
+	blk_lpos->begin = begin_lpos;
+	blk_lpos->next = next_lpos;
+
+	return &blk->data[0];
+}
+
+/*
+ * Try to resize an existing data block associated with the descriptor
+ * specified by @id. If the resized data block should become wrapped, it
+ * copies the old data to the new data block. If @size yields a data block
+ * with the same or less size, the data block is left as is.
+ *
+ * Fail if this is not the last allocated data block or if there is not
+ * enough space or it is not possible make enough space.
+ *
+ * Return a pointer to the beginning of the entire data buffer or NULL on
+ * failure.
+ */
+static char *data_realloc(struct printk_ringbuffer *rb, unsigned int size,
+			  struct prb_data_blk_lpos *blk_lpos, unsigned long id)
+{
+	struct prb_data_ring *data_ring = &rb->text_data_ring;
+	struct prb_data_block *blk;
+	unsigned long head_lpos;
+	unsigned long next_lpos;
+	bool wrapped;
+
+	/* Reallocation only works if @blk_lpos is the newest data block. */
+	head_lpos = atomic_long_read(&data_ring->head_lpos);
+	if (head_lpos != blk_lpos->next)
+		return NULL;
+
+	/* Keep track if @blk_lpos was a wrapping data block. */
+	wrapped = (DATA_WRAPS(data_ring, blk_lpos->begin) != DATA_WRAPS(data_ring, blk_lpos->next));
+
+	size = to_blk_size(size);
+
+	next_lpos = get_next_lpos(data_ring, blk_lpos->begin, size);
+
+	/* If the data block does not increase, there is nothing to do. */
+	if (head_lpos - next_lpos < DATA_SIZE(data_ring)) {
+		if (wrapped)
+			blk = to_block(data_ring, 0);
+		else
+			blk = to_block(data_ring, blk_lpos->begin);
+		return &blk->data[0];
+	}
+
+	if (!data_push_tail(rb, next_lpos - DATA_SIZE(data_ring)))
+		return NULL;
+
+	/* The memory barrier involvement is the same as data_alloc:A. */
+	if (!atomic_long_try_cmpxchg(&data_ring->head_lpos, &head_lpos,
+				     next_lpos)) { /* LMM(data_realloc:A) */
+		return NULL;
+	}
+
+	blk = to_block(data_ring, blk_lpos->begin);
+
+	if (DATA_WRAPS(data_ring, blk_lpos->begin) != DATA_WRAPS(data_ring, next_lpos)) {
+		struct prb_data_block *old_blk = blk;
+
+		/* Wrapping data blocks store their data at the beginning. */
+		blk = to_block(data_ring, 0);
+
+		/*
+		 * Store the ID on the wrapped block for consistency.
+		 * The printk_ringbuffer does not actually use it.
+		 */
+		blk->id = id;
+
+		if (!wrapped) {
+			/*
+			 * Since the allocated space is now in the newly
+			 * created wrapping data block, copy the content
+			 * from the old data block.
+			 */
+			memcpy(&blk->data[0], &old_blk->data[0],
+			       (blk_lpos->next - blk_lpos->begin) - sizeof(blk->id));
+		}
+	}
+
+	blk_lpos->next = next_lpos;
+
+	return &blk->data[0];
+}
+
+/* Return the number of bytes used by a data block. */
+static unsigned int space_used(struct prb_data_ring *data_ring,
+			       struct prb_data_blk_lpos *blk_lpos)
+{
+	/* Data-less blocks take no space. */
+	if (BLK_DATALESS(blk_lpos))
+		return 0;
+
+	if (DATA_WRAPS(data_ring, blk_lpos->begin) == DATA_WRAPS(data_ring, blk_lpos->next)) {
+		/* Data block does not wrap. */
+		return (DATA_INDEX(data_ring, blk_lpos->next) -
+			DATA_INDEX(data_ring, blk_lpos->begin));
+	}
+
+	/*
+	 * For wrapping data blocks, the trailing (wasted) space is
+	 * also counted.
+	 */
+	return (DATA_INDEX(data_ring, blk_lpos->next) +
+		DATA_SIZE(data_ring) - DATA_INDEX(data_ring, blk_lpos->begin));
+}
+
+/*
+ * Given @blk_lpos, return a pointer to the writer data from the data block
+ * and calculate the size of the data part. A NULL pointer is returned if
+ * @blk_lpos specifies values that could never be legal.
+ *
+ * This function (used by readers) performs strict validation on the lpos
+ * values to possibly detect bugs in the writer code. A WARN_ON_ONCE() is
+ * triggered if an internal error is detected.
+ */
+static const char *get_data(struct prb_data_ring *data_ring,
+			    struct prb_data_blk_lpos *blk_lpos,
+			    unsigned int *data_size)
+{
+	struct prb_data_block *db;
+
+	/* Data-less data block description. */
+	if (BLK_DATALESS(blk_lpos)) {
+		if (blk_lpos->begin == NO_LPOS && blk_lpos->next == NO_LPOS) {
+			*data_size = 0;
+			return "";
+		}
+		return NULL;
+	}
+
+	/* Regular data block: @begin less than @next and in same wrap. */
+	if (DATA_WRAPS(data_ring, blk_lpos->begin) == DATA_WRAPS(data_ring, blk_lpos->next) &&
+	    blk_lpos->begin < blk_lpos->next) {
+		db = to_block(data_ring, blk_lpos->begin);
+		*data_size = blk_lpos->next - blk_lpos->begin;
+
+	/* Wrapping data block: @begin is one wrap behind @next. */
+	} else if (DATA_WRAPS(data_ring, blk_lpos->begin + DATA_SIZE(data_ring)) ==
+		   DATA_WRAPS(data_ring, blk_lpos->next)) {
+		db = to_block(data_ring, 0);
+		*data_size = DATA_INDEX(data_ring, blk_lpos->next);
+
+	/* Illegal block description. */
+	} else {
+		WARN_ON_ONCE(1);
+		return NULL;
+	}
+
+	/* A valid data block will always be aligned to the ID size. */
+	if (WARN_ON_ONCE(blk_lpos->begin != ALIGN(blk_lpos->begin, sizeof(db->id))) ||
+	    WARN_ON_ONCE(blk_lpos->next != ALIGN(blk_lpos->next, sizeof(db->id)))) {
+		return NULL;
+	}
+
+	/* A valid data block will always have at least an ID. */
+	if (WARN_ON_ONCE(*data_size < sizeof(db->id)))
+		return NULL;
+
+	/* Subtract block ID space from size to reflect data size. */
+	*data_size -= sizeof(db->id);
+
+	return &db->data[0];
+}
+
+/*
+ * Attempt to transition the newest descriptor from committed back to reserved
+ * so that the record can be modified by a writer again. This is only possible
+ * if the descriptor is not yet finalized and the provided @caller_id matches.
+ */
+static struct prb_desc *desc_reopen_last(struct prb_desc_ring *desc_ring,
+					 u32 caller_id, unsigned long *id_out)
+{
+	unsigned long prev_state_val;
+	enum desc_state d_state;
+	struct prb_desc desc;
+	struct prb_desc *d;
+	unsigned long id;
+	u32 cid;
+
+	id = atomic_long_read(&desc_ring->head_id);
+
+	/*
+	 * To reduce unnecessarily reopening, first check if the descriptor
+	 * state and caller ID are correct.
+	 */
+	d_state = desc_read(desc_ring, id, &desc, NULL, &cid);
+	if (d_state != desc_committed || cid != caller_id)
+		return NULL;
+
+	d = to_desc(desc_ring, id);
+
+	prev_state_val = DESC_SV(id, desc_committed);
+
+	/*
+	 * Guarantee the reserved state is stored before reading any
+	 * record data. A full memory barrier is needed because @state_var
+	 * modification is followed by reading. This pairs with _prb_commit:B.
+	 *
+	 * Memory barrier involvement:
+	 *
+	 * If desc_reopen_last:A reads from _prb_commit:B, then
+	 * prb_reserve_in_last:A reads from _prb_commit:A.
+	 *
+	 * Relies on:
+	 *
+	 * WMB from _prb_commit:A to _prb_commit:B
+	 *    matching
+	 * MB If desc_reopen_last:A to prb_reserve_in_last:A
+	 */
+	if (!atomic_long_try_cmpxchg(&d->state_var, &prev_state_val,
+			DESC_SV(id, desc_reserved))) { /* LMM(desc_reopen_last:A) */
+		return NULL;
+	}
+
+	*id_out = id;
+	return d;
+}
+
+/**
+ * prb_reserve_in_last() - Re-reserve and extend the space in the ringbuffer
+ *                         used by the newest record.
+ *
+ * @e:         The entry structure to setup.
+ * @rb:        The ringbuffer to re-reserve and extend data in.
+ * @r:         The record structure to allocate buffers for.
+ * @caller_id: The caller ID of the caller (reserving writer).
+ * @max_size:  Fail if the extended size would be greater than this.
+ *
+ * This is the public function available to writers to re-reserve and extend
+ * data.
+ *
+ * The writer specifies the text size to extend (not the new total size) by
+ * setting the @text_buf_size field of @r. To ensure proper initialization
+ * of @r, prb_rec_init_wr() should be used.
+ *
+ * This function will fail if @caller_id does not match the caller ID of the
+ * newest record. In that case the caller must reserve new data using
+ * prb_reserve().
+ *
+ * Context: Any context. Disables local interrupts on success.
+ * Return: true if text data could be extended, otherwise false.
+ *
+ * On success:
+ *
+ *   - @r->text_buf points to the beginning of the entire text buffer.
+ *
+ *   - @r->text_buf_size is set to the new total size of the buffer.
+ *
+ *   - @r->info is not touched so that @r->info->text_len could be used
+ *     to append the text.
+ *
+ *   - prb_record_text_space() can be used on @e to query the new
+ *     actually used space.
+ *
+ * Important: All @r->info fields will already be set with the current values
+ *            for the record. I.e. @r->info->text_len will be less than
+ *            @text_buf_size. Writers can use @r->info->text_len to know
+ *            where concatenation begins and writers should update
+ *            @r->info->text_len after concatenating.
+ */
+bool prb_reserve_in_last(struct prb_reserved_entry *e, struct printk_ringbuffer *rb,
+			 struct printk_record *r, u32 caller_id, unsigned int max_size)
+{
+	struct prb_desc_ring *desc_ring = &rb->desc_ring;
+	struct printk_info *info;
+	unsigned int data_size;
+	struct prb_desc *d;
+	unsigned long id;
+
+	local_irq_save(e->irqflags);
+
+	/* Transition the newest descriptor back to the reserved state. */
+	d = desc_reopen_last(desc_ring, caller_id, &id);
+	if (!d) {
+		local_irq_restore(e->irqflags);
+		goto fail_reopen;
+	}
+
+	/* Now the writer has exclusive access: LMM(prb_reserve_in_last:A) */
+
+	info = to_info(desc_ring, id);
+
+	/*
+	 * Set the @e fields here so that prb_commit() can be used if
+	 * anything fails from now on.
+	 */
+	e->rb = rb;
+	e->id = id;
+
+	/*
+	 * desc_reopen_last() checked the caller_id, but there was no
+	 * exclusive access at that point. The descriptor may have
+	 * changed since then.
+	 */
+	if (caller_id != info->caller_id)
+		goto fail;
+
+	if (BLK_DATALESS(&d->text_blk_lpos)) {
+		if (WARN_ON_ONCE(info->text_len != 0)) {
+			pr_warn_once("wrong text_len value (%hu, expecting 0)\n",
+				     info->text_len);
+			info->text_len = 0;
+		}
+
+		if (!data_check_size(&rb->text_data_ring, r->text_buf_size))
+			goto fail;
+
+		if (r->text_buf_size > max_size)
+			goto fail;
+
+		r->text_buf = data_alloc(rb, r->text_buf_size,
+					 &d->text_blk_lpos, id);
+	} else {
+		if (!get_data(&rb->text_data_ring, &d->text_blk_lpos, &data_size))
+			goto fail;
+
+		/*
+		 * Increase the buffer size to include the original size. If
+		 * the meta data (@text_len) is not sane, use the full data
+		 * block size.
+		 */
+		if (WARN_ON_ONCE(info->text_len > data_size)) {
+			pr_warn_once("wrong text_len value (%hu, expecting <=%u)\n",
+				     info->text_len, data_size);
+			info->text_len = data_size;
+		}
+		r->text_buf_size += info->text_len;
+
+		if (!data_check_size(&rb->text_data_ring, r->text_buf_size))
+			goto fail;
+
+		if (r->text_buf_size > max_size)
+			goto fail;
+
+		r->text_buf = data_realloc(rb, r->text_buf_size,
+					   &d->text_blk_lpos, id);
+	}
+	if (r->text_buf_size && !r->text_buf)
+		goto fail;
+
+	r->info = info;
+
+	e->text_space = space_used(&rb->text_data_ring, &d->text_blk_lpos);
+
+	return true;
+fail:
+	prb_commit(e);
+	/* prb_commit() re-enabled interrupts. */
+fail_reopen:
+	/* Make it clear to the caller that the re-reserve failed. */
+	memset(r, 0, sizeof(*r));
+	return false;
+}
+
+/*
+ * Attempt to finalize a specified descriptor. If this fails, the descriptor
+ * is either already final or it will finalize itself when the writer commits.
+ */
+static void desc_make_final(struct prb_desc_ring *desc_ring, unsigned long id)
+{
+	unsigned long prev_state_val = DESC_SV(id, desc_committed);
+	struct prb_desc *d = to_desc(desc_ring, id);
+
+	atomic_long_cmpxchg_relaxed(&d->state_var, prev_state_val,
+			DESC_SV(id, desc_finalized)); /* LMM(desc_make_final:A) */
+
+	/* Best effort to remember the last finalized @id. */
+	atomic_long_set(&desc_ring->last_finalized_id, id);
+}
+
+/**
+ * prb_reserve() - Reserve space in the ringbuffer.
+ *
+ * @e:  The entry structure to setup.
+ * @rb: The ringbuffer to reserve data in.
+ * @r:  The record structure to allocate buffers for.
+ *
+ * This is the public function available to writers to reserve data.
+ *
+ * The writer specifies the text size to reserve by setting the
+ * @text_buf_size field of @r. To ensure proper initialization of @r,
+ * prb_rec_init_wr() should be used.
+ *
+ * Context: Any context. Disables local interrupts on success.
+ * Return: true if at least text data could be allocated, otherwise false.
+ *
+ * On success, the fields @info and @text_buf of @r will be set by this
+ * function and should be filled in by the writer before committing. Also
+ * on success, prb_record_text_space() can be used on @e to query the actual
+ * space used for the text data block.
+ *
+ * Important: @info->text_len needs to be set correctly by the writer in
+ *            order for data to be readable and/or extended. Its value
+ *            is initialized to 0.
+ */
+bool prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb,
+		 struct printk_record *r)
+{
+	struct prb_desc_ring *desc_ring = &rb->desc_ring;
+	struct printk_info *info;
+	struct prb_desc *d;
+	unsigned long id;
+	u64 seq;
+
+	if (!data_check_size(&rb->text_data_ring, r->text_buf_size))
+		goto fail;
+
+	/*
+	 * Descriptors in the reserved state act as blockers to all further
+	 * reservations once the desc_ring has fully wrapped. Disable
+	 * interrupts during the reserve/commit window in order to minimize
+	 * the likelihood of this happening.
+	 */
+	local_irq_save(e->irqflags);
+
+	if (!desc_reserve(rb, &id)) {
+		/* Descriptor reservation failures are tracked. */
+		atomic_long_inc(&rb->fail);
+		local_irq_restore(e->irqflags);
+		goto fail;
+	}
+
+	d = to_desc(desc_ring, id);
+	info = to_info(desc_ring, id);
+
+	/*
+	 * All @info fields (except @seq) are cleared and must be filled in
+	 * by the writer. Save @seq before clearing because it is used to
+	 * determine the new sequence number.
+	 */
+	seq = info->seq;
+	memset(info, 0, sizeof(*info));
+
+	/*
+	 * Set the @e fields here so that prb_commit() can be used if
+	 * text data allocation fails.
+	 */
+	e->rb = rb;
+	e->id = id;
+
+	/*
+	 * Initialize the sequence number if it has "never been set".
+	 * Otherwise just increment it by a full wrap.
+	 *
+	 * @seq is considered "never been set" if it has a value of 0,
+	 * _except_ for @infos[0], which was specially setup by the ringbuffer
+	 * initializer and therefore is always considered as set.
+	 *
+	 * See the "Bootstrap" comment block in printk_ringbuffer.h for
+	 * details about how the initializer bootstraps the descriptors.
+	 */
+	if (seq == 0 && DESC_INDEX(desc_ring, id) != 0)
+		info->seq = DESC_INDEX(desc_ring, id);
+	else
+		info->seq = seq + DESCS_COUNT(desc_ring);
+
+	/*
+	 * New data is about to be reserved. Once that happens, previous
+	 * descriptors are no longer able to be extended. Finalize the
+	 * previous descriptor now so that it can be made available to
+	 * readers. (For seq==0 there is no previous descriptor.)
+	 */
+	if (info->seq > 0)
+		desc_make_final(desc_ring, DESC_ID(id - 1));
+
+	r->text_buf = data_alloc(rb, r->text_buf_size, &d->text_blk_lpos, id);
+	/* If text data allocation fails, a data-less record is committed. */
+	if (r->text_buf_size && !r->text_buf) {
+		prb_commit(e);
+		/* prb_commit() re-enabled interrupts. */
+		goto fail;
+	}
+
+	r->info = info;
+
+	/* Record full text space used by record. */
+	e->text_space = space_used(&rb->text_data_ring, &d->text_blk_lpos);
+
+	return true;
+fail:
+	/* Make it clear to the caller that the reserve failed. */
+	memset(r, 0, sizeof(*r));
+	return false;
+}
+
+/* Commit the data (possibly finalizing it) and restore interrupts. */
+static void _prb_commit(struct prb_reserved_entry *e, unsigned long state_val)
+{
+	struct prb_desc_ring *desc_ring = &e->rb->desc_ring;
+	struct prb_desc *d = to_desc(desc_ring, e->id);
+	unsigned long prev_state_val = DESC_SV(e->id, desc_reserved);
+
+	/* Now the writer has finished all writing: LMM(_prb_commit:A) */
+
+	/*
+	 * Set the descriptor as committed. See "ABA Issues" about why
+	 * cmpxchg() instead of set() is used.
+	 *
+	 * 1  Guarantee all record data is stored before the descriptor state
+	 *    is stored as committed. A write memory barrier is sufficient
+	 *    for this. This pairs with desc_read:B and desc_reopen_last:A.
+	 *
+	 * 2. Guarantee the descriptor state is stored as committed before
+	 *    re-checking the head ID in order to possibly finalize this
+	 *    descriptor. This pairs with desc_reserve:D.
+	 *
+	 *    Memory barrier involvement:
+	 *
+	 *    If prb_commit:A reads from desc_reserve:D, then
+	 *    desc_make_final:A reads from _prb_commit:B.
+	 *
+	 *    Relies on:
+	 *
+	 *    MB _prb_commit:B to prb_commit:A
+	 *       matching
+	 *    MB desc_reserve:D to desc_make_final:A
+	 */
+	if (!atomic_long_try_cmpxchg(&d->state_var, &prev_state_val,
+			DESC_SV(e->id, state_val))) { /* LMM(_prb_commit:B) */
+		WARN_ON_ONCE(1);
+	}
+
+	/* Restore interrupts, the reserve/commit window is finished. */
+	local_irq_restore(e->irqflags);
+}
+
+/**
+ * prb_commit() - Commit (previously reserved) data to the ringbuffer.
+ *
+ * @e: The entry containing the reserved data information.
+ *
+ * This is the public function available to writers to commit data.
+ *
+ * Note that the data is not yet available to readers until it is finalized.
+ * Finalizing happens automatically when space for the next record is
+ * reserved.
+ *
+ * See prb_final_commit() for a version of this function that finalizes
+ * immediately.
+ *
+ * Context: Any context. Enables local interrupts.
+ */
+void prb_commit(struct prb_reserved_entry *e)
+{
+	struct prb_desc_ring *desc_ring = &e->rb->desc_ring;
+	unsigned long head_id;
+
+	_prb_commit(e, desc_committed);
+
+	/*
+	 * If this descriptor is no longer the head (i.e. a new record has
+	 * been allocated), extending the data for this record is no longer
+	 * allowed and therefore it must be finalized.
+	 */
+	head_id = atomic_long_read(&desc_ring->head_id); /* LMM(prb_commit:A) */
+	if (head_id != e->id)
+		desc_make_final(desc_ring, e->id);
+}
+
+/**
+ * prb_final_commit() - Commit and finalize (previously reserved) data to
+ *                      the ringbuffer.
+ *
+ * @e: The entry containing the reserved data information.
+ *
+ * This is the public function available to writers to commit+finalize data.
+ *
+ * By finalizing, the data is made immediately available to readers.
+ *
+ * This function should only be used if there are no intentions of extending
+ * this data using prb_reserve_in_last().
+ *
+ * Context: Any context. Enables local interrupts.
+ */
+void prb_final_commit(struct prb_reserved_entry *e)
+{
+	struct prb_desc_ring *desc_ring = &e->rb->desc_ring;
+
+	_prb_commit(e, desc_finalized);
+
+	/* Best effort to remember the last finalized @id. */
+	atomic_long_set(&desc_ring->last_finalized_id, e->id);
+}
+
+/*
+ * Count the number of lines in provided text. All text has at least 1 line
+ * (even if @text_size is 0). Each '\n' processed is counted as an additional
+ * line.
+ */
+static unsigned int count_lines(const char *text, unsigned int text_size)
+{
+	unsigned int next_size = text_size;
+	unsigned int line_count = 1;
+	const char *next = text;
+
+	while (next_size) {
+		next = memchr(next, '\n', next_size);
+		if (!next)
+			break;
+		line_count++;
+		next++;
+		next_size = text_size - (next - text);
+	}
+
+	return line_count;
+}
+
+/*
+ * Given @blk_lpos, copy an expected @len of data into the provided buffer.
+ * If @line_count is provided, count the number of lines in the data.
+ *
+ * This function (used by readers) performs strict validation on the data
+ * size to possibly detect bugs in the writer code. A WARN_ON_ONCE() is
+ * triggered if an internal error is detected.
+ */
+static bool copy_data(struct prb_data_ring *data_ring,
+		      struct prb_data_blk_lpos *blk_lpos, u16 len, char *buf,
+		      unsigned int buf_size, unsigned int *line_count)
+{
+	unsigned int data_size;
+	const char *data;
+
+	/* Caller might not want any data. */
+	if ((!buf || !buf_size) && !line_count)
+		return true;
+
+	data = get_data(data_ring, blk_lpos, &data_size);
+	if (!data)
+		return false;
+
+	/*
+	 * Actual cannot be less than expected. It can be more than expected
+	 * because of the trailing alignment padding.
+	 *
+	 * Note that invalid @len values can occur because the caller loads
+	 * the value during an allowed data race.
+	 */
+	if (data_size < (unsigned int)len)
+		return false;
+
+	/* Caller interested in the line count? */
+	if (line_count)
+		*line_count = count_lines(data, len);
+
+	/* Caller interested in the data content? */
+	if (!buf || !buf_size)
+		return true;
+
+	data_size = min_t(unsigned int, buf_size, len);
+
+	memcpy(&buf[0], data, data_size); /* LMM(copy_data:A) */
+	return true;
+}
+
+/*
+ * This is an extended version of desc_read(). It gets a copy of a specified
+ * descriptor. However, it also verifies that the record is finalized and has
+ * the sequence number @seq. On success, 0 is returned.
+ *
+ * Error return values:
+ * -EINVAL: A finalized record with sequence number @seq does not exist.
+ * -ENOENT: A finalized record with sequence number @seq exists, but its data
+ *          is not available. This is a valid record, so readers should
+ *          continue with the next record.
+ */
+static int desc_read_finalized_seq(struct prb_desc_ring *desc_ring,
+				   unsigned long id, u64 seq,
+				   struct prb_desc *desc_out)
+{
+	struct prb_data_blk_lpos *blk_lpos = &desc_out->text_blk_lpos;
+	enum desc_state d_state;
+	u64 s;
+
+	d_state = desc_read(desc_ring, id, desc_out, &s, NULL);
+
+	/*
+	 * An unexpected @id (desc_miss) or @seq mismatch means the record
+	 * does not exist. A descriptor in the reserved or committed state
+	 * means the record does not yet exist for the reader.
+	 */
+	if (d_state == desc_miss ||
+	    d_state == desc_reserved ||
+	    d_state == desc_committed ||
+	    s != seq) {
+		return -EINVAL;
+	}
+
+	/*
+	 * A descriptor in the reusable state may no longer have its data
+	 * available; report it as existing but with lost data. Or the record
+	 * may actually be a record with lost data.
+	 */
+	if (d_state == desc_reusable ||
+	    (blk_lpos->begin == FAILED_LPOS && blk_lpos->next == FAILED_LPOS)) {
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+/*
+ * Copy the ringbuffer data from the record with @seq to the provided
+ * @r buffer. On success, 0 is returned.
+ *
+ * See desc_read_finalized_seq() for error return values.
+ */
+static int prb_read(struct printk_ringbuffer *rb, u64 seq,
+		    struct printk_record *r, unsigned int *line_count)
+{
+	struct prb_desc_ring *desc_ring = &rb->desc_ring;
+	struct printk_info *info = to_info(desc_ring, seq);
+	struct prb_desc *rdesc = to_desc(desc_ring, seq);
+	atomic_long_t *state_var = &rdesc->state_var;
+	struct prb_desc desc;
+	unsigned long id;
+	int err;
+
+	/* Extract the ID, used to specify the descriptor to read. */
+	id = DESC_ID(atomic_long_read(state_var));
+
+	/* Get a local copy of the correct descriptor (if available). */
+	err = desc_read_finalized_seq(desc_ring, id, seq, &desc);
+
+	/*
+	 * If @r is NULL, the caller is only interested in the availability
+	 * of the record.
+	 */
+	if (err || !r)
+		return err;
+
+	/* If requested, copy meta data. */
+	if (r->info)
+		memcpy(r->info, info, sizeof(*(r->info)));
+
+	/* Copy text data. If it fails, this is a data-less record. */
+	if (!copy_data(&rb->text_data_ring, &desc.text_blk_lpos, info->text_len,
+		       r->text_buf, r->text_buf_size, line_count)) {
+		return -ENOENT;
+	}
+
+	/* Ensure the record is still finalized and has the same @seq. */
+	return desc_read_finalized_seq(desc_ring, id, seq, &desc);
+}
+
+/* Get the sequence number of the tail descriptor. */
+static u64 prb_first_seq(struct printk_ringbuffer *rb)
+{
+	struct prb_desc_ring *desc_ring = &rb->desc_ring;
+	enum desc_state d_state;
+	struct prb_desc desc;
+	unsigned long id;
+	u64 seq;
+
+	for (;;) {
+		id = atomic_long_read(&rb->desc_ring.tail_id); /* LMM(prb_first_seq:A) */
+
+		d_state = desc_read(desc_ring, id, &desc, &seq, NULL); /* LMM(prb_first_seq:B) */
+
+		/*
+		 * This loop will not be infinite because the tail is
+		 * _always_ in the finalized or reusable state.
+		 */
+		if (d_state == desc_finalized || d_state == desc_reusable)
+			break;
+
+		/*
+		 * Guarantee the last state load from desc_read() is before
+		 * reloading @tail_id in order to see a new tail in the case
+		 * that the descriptor has been recycled. This pairs with
+		 * desc_reserve:D.
+		 *
+		 * Memory barrier involvement:
+		 *
+		 * If prb_first_seq:B reads from desc_reserve:F, then
+		 * prb_first_seq:A reads from desc_push_tail:B.
+		 *
+		 * Relies on:
+		 *
+		 * MB from desc_push_tail:B to desc_reserve:F
+		 *    matching
+		 * RMB prb_first_seq:B to prb_first_seq:A
+		 */
+		smp_rmb(); /* LMM(prb_first_seq:C) */
+	}
+
+	return seq;
+}
+
+/*
+ * Non-blocking read of a record. Updates @seq to the last finalized record
+ * (which may have no data available).
+ *
+ * See the description of prb_read_valid() and prb_read_valid_info()
+ * for details.
+ */
+static bool _prb_read_valid(struct printk_ringbuffer *rb, u64 *seq,
+			    struct printk_record *r, unsigned int *line_count)
+{
+	u64 tail_seq;
+	int err;
+
+	while ((err = prb_read(rb, *seq, r, line_count))) {
+		tail_seq = prb_first_seq(rb);
+
+		if (*seq < tail_seq) {
+			/*
+			 * Behind the tail. Catch up and try again. This
+			 * can happen for -ENOENT and -EINVAL cases.
+			 */
+			*seq = tail_seq;
+
+		} else if (err == -ENOENT) {
+			/* Record exists, but no data available. Skip. */
+			(*seq)++;
+
+		} else {
+			/* Non-existent/non-finalized record. Must stop. */
+			return false;
+		}
+	}
+
+	return true;
+}
+
+/**
+ * prb_read_valid() - Non-blocking read of a requested record or (if gone)
+ *                    the next available record.
+ *
+ * @rb:  The ringbuffer to read from.
+ * @seq: The sequence number of the record to read.
+ * @r:   A record data buffer to store the read record to.
+ *
+ * This is the public function available to readers to read a record.
+ *
+ * The reader provides the @info and @text_buf buffers of @r to be
+ * filled in. Any of the buffer pointers can be set to NULL if the reader
+ * is not interested in that data. To ensure proper initialization of @r,
+ * prb_rec_init_rd() should be used.
+ *
+ * Context: Any context.
+ * Return: true if a record was read, otherwise false.
+ *
+ * On success, the reader must check r->info.seq to see which record was
+ * actually read. This allows the reader to detect dropped records.
+ *
+ * Failure means @seq refers to a not yet written record.
+ */
+bool prb_read_valid(struct printk_ringbuffer *rb, u64 seq,
+		    struct printk_record *r)
+{
+	return _prb_read_valid(rb, &seq, r, NULL);
+}
+
+/**
+ * prb_read_valid_info() - Non-blocking read of meta data for a requested
+ *                         record or (if gone) the next available record.
+ *
+ * @rb:         The ringbuffer to read from.
+ * @seq:        The sequence number of the record to read.
+ * @info:       A buffer to store the read record meta data to.
+ * @line_count: A buffer to store the number of lines in the record text.
+ *
+ * This is the public function available to readers to read only the
+ * meta data of a record.
+ *
+ * The reader provides the @info, @line_count buffers to be filled in.
+ * Either of the buffer pointers can be set to NULL if the reader is not
+ * interested in that data.
+ *
+ * Context: Any context.
+ * Return: true if a record's meta data was read, otherwise false.
+ *
+ * On success, the reader must check info->seq to see which record meta data
+ * was actually read. This allows the reader to detect dropped records.
+ *
+ * Failure means @seq refers to a not yet written record.
+ */
+bool prb_read_valid_info(struct printk_ringbuffer *rb, u64 seq,
+			 struct printk_info *info, unsigned int *line_count)
+{
+	struct printk_record r;
+
+	prb_rec_init_rd(&r, info, NULL, 0);
+
+	return _prb_read_valid(rb, &seq, &r, line_count);
+}
+
+/**
+ * prb_first_valid_seq() - Get the sequence number of the oldest available
+ *                         record.
+ *
+ * @rb: The ringbuffer to get the sequence number from.
+ *
+ * This is the public function available to readers to see what the
+ * first/oldest valid sequence number is.
+ *
+ * This provides readers a starting point to begin iterating the ringbuffer.
+ *
+ * Context: Any context.
+ * Return: The sequence number of the first/oldest record or, if the
+ *         ringbuffer is empty, 0 is returned.
+ */
+u64 prb_first_valid_seq(struct printk_ringbuffer *rb)
+{
+	u64 seq = 0;
+
+	if (!_prb_read_valid(rb, &seq, NULL, NULL))
+		return 0;
+
+	return seq;
+}
+
+/**
+ * prb_next_seq() - Get the sequence number after the last available record.
+ *
+ * @rb:  The ringbuffer to get the sequence number from.
+ *
+ * This is the public function available to readers to see what the next
+ * newest sequence number available to readers will be.
+ *
+ * This provides readers a sequence number to jump to if all currently
+ * available records should be skipped.
+ *
+ * Context: Any context.
+ * Return: The sequence number of the next newest (not yet available) record
+ *         for readers.
+ */
+u64 prb_next_seq(struct printk_ringbuffer *rb)
+{
+	struct prb_desc_ring *desc_ring = &rb->desc_ring;
+	enum desc_state d_state;
+	unsigned long id;
+	u64 seq;
+
+	/* Check if the cached @id still points to a valid @seq. */
+	id = atomic_long_read(&desc_ring->last_finalized_id);
+	d_state = desc_read(desc_ring, id, NULL, &seq, NULL);
+
+	if (d_state == desc_finalized || d_state == desc_reusable) {
+		/*
+		 * Begin searching after the last finalized record.
+		 *
+		 * On 0, the search must begin at 0 because of hack#2
+		 * of the bootstrapping phase it is not known if a
+		 * record at index 0 exists.
+		 */
+		if (seq != 0)
+			seq++;
+	} else {
+		/*
+		 * The information about the last finalized sequence number
+		 * has gone. It should happen only when there is a flood of
+		 * new messages and the ringbuffer is rapidly recycled.
+		 * Give up and start from the beginning.
+		 */
+		seq = 0;
+	}
+
+	/*
+	 * The information about the last finalized @seq might be inaccurate.
+	 * Search forward to find the current one.
+	 */
+	while (_prb_read_valid(rb, &seq, NULL, NULL))
+		seq++;
+
+	return seq;
+}
+
+/**
+ * prb_init() - Initialize a ringbuffer to use provided external buffers.
+ *
+ * @rb:       The ringbuffer to initialize.
+ * @text_buf: The data buffer for text data.
+ * @textbits: The size of @text_buf as a power-of-2 value.
+ * @descs:    The descriptor buffer for ringbuffer records.
+ * @descbits: The count of @descs items as a power-of-2 value.
+ * @infos:    The printk_info buffer for ringbuffer records.
+ *
+ * This is the public function available to writers to setup a ringbuffer
+ * during runtime using provided buffers.
+ *
+ * This must match the initialization of DEFINE_PRINTKRB().
+ *
+ * Context: Any context.
+ */
+void prb_init(struct printk_ringbuffer *rb,
+	      char *text_buf, unsigned int textbits,
+	      struct prb_desc *descs, unsigned int descbits,
+	      struct printk_info *infos)
+{
+	memset(descs, 0, _DESCS_COUNT(descbits) * sizeof(descs[0]));
+	memset(infos, 0, _DESCS_COUNT(descbits) * sizeof(infos[0]));
+
+	rb->desc_ring.count_bits = descbits;
+	rb->desc_ring.descs = descs;
+	rb->desc_ring.infos = infos;
+	atomic_long_set(&rb->desc_ring.head_id, DESC0_ID(descbits));
+	atomic_long_set(&rb->desc_ring.tail_id, DESC0_ID(descbits));
+	atomic_long_set(&rb->desc_ring.last_finalized_id, DESC0_ID(descbits));
+
+	rb->text_data_ring.size_bits = textbits;
+	rb->text_data_ring.data = text_buf;
+	atomic_long_set(&rb->text_data_ring.head_lpos, BLK0_LPOS(textbits));
+	atomic_long_set(&rb->text_data_ring.tail_lpos, BLK0_LPOS(textbits));
+
+	atomic_long_set(&rb->fail, 0);
+
+	atomic_long_set(&(descs[_DESCS_COUNT(descbits) - 1].state_var), DESC0_SV(descbits));
+	descs[_DESCS_COUNT(descbits) - 1].text_blk_lpos.begin = FAILED_LPOS;
+	descs[_DESCS_COUNT(descbits) - 1].text_blk_lpos.next = FAILED_LPOS;
+
+	infos[0].seq = -(u64)_DESCS_COUNT(descbits);
+	infos[_DESCS_COUNT(descbits) - 1].seq = 0;
+}
+
+/**
+ * prb_record_text_space() - Query the full actual used ringbuffer space for
+ *                           the text data of a reserved entry.
+ *
+ * @e: The successfully reserved entry to query.
+ *
+ * This is the public function available to writers to see how much actual
+ * space is used in the ringbuffer to store the text data of the specified
+ * entry.
+ *
+ * This function is only valid if @e has been successfully reserved using
+ * prb_reserve().
+ *
+ * Context: Any context.
+ * Return: The size in bytes used by the text data of the associated record.
+ */
+unsigned int prb_record_text_space(struct prb_reserved_entry *e)
+{
+	return e->text_space;
+}
diff --git a/kernel/printk/printk_ringbuffer.h b/kernel/printk/printk_ringbuffer.h
new file mode 100644
index 000000000..18cd25e48
--- /dev/null
+++ b/kernel/printk/printk_ringbuffer.h
@@ -0,0 +1,384 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _KERNEL_PRINTK_RINGBUFFER_H
+#define _KERNEL_PRINTK_RINGBUFFER_H
+
+#include <linux/atomic.h>
+#include <linux/dev_printk.h>
+
+/*
+ * Meta information about each stored message.
+ *
+ * All fields are set by the printk code except for @seq, which is
+ * set by the ringbuffer code.
+ */
+struct printk_info {
+	u64	seq;		/* sequence number */
+	u64	ts_nsec;	/* timestamp in nanoseconds */
+	u16	text_len;	/* length of text message */
+	u8	facility;	/* syslog facility */
+	u8	flags:5;	/* internal record flags */
+	u8	level:3;	/* syslog level */
+	u32	caller_id;	/* thread id or processor id */
+
+	struct dev_printk_info	dev_info;
+};
+
+/*
+ * A structure providing the buffers, used by writers and readers.
+ *
+ * Writers:
+ * Using prb_rec_init_wr(), a writer sets @text_buf_size before calling
+ * prb_reserve(). On success, prb_reserve() sets @info and @text_buf to
+ * buffers reserved for that writer.
+ *
+ * Readers:
+ * Using prb_rec_init_rd(), a reader sets all fields before calling
+ * prb_read_valid(). Note that the reader provides the @info and @text_buf,
+ * buffers. On success, the struct pointed to by @info will be filled and
+ * the char array pointed to by @text_buf will be filled with text data.
+ */
+struct printk_record {
+	struct printk_info	*info;
+	char			*text_buf;
+	unsigned int		text_buf_size;
+};
+
+/* Specifies the logical position and span of a data block. */
+struct prb_data_blk_lpos {
+	unsigned long	begin;
+	unsigned long	next;
+};
+
+/*
+ * A descriptor: the complete meta-data for a record.
+ *
+ * @state_var: A bitwise combination of descriptor ID and descriptor state.
+ */
+struct prb_desc {
+	atomic_long_t			state_var;
+	struct prb_data_blk_lpos	text_blk_lpos;
+};
+
+/* A ringbuffer of "ID + data" elements. */
+struct prb_data_ring {
+	unsigned int	size_bits;
+	char		*data;
+	atomic_long_t	head_lpos;
+	atomic_long_t	tail_lpos;
+};
+
+/* A ringbuffer of "struct prb_desc" elements. */
+struct prb_desc_ring {
+	unsigned int		count_bits;
+	struct prb_desc		*descs;
+	struct printk_info	*infos;
+	atomic_long_t		head_id;
+	atomic_long_t		tail_id;
+	atomic_long_t		last_finalized_id;
+};
+
+/*
+ * The high level structure representing the printk ringbuffer.
+ *
+ * @fail: Count of failed prb_reserve() calls where not even a data-less
+ *        record was created.
+ */
+struct printk_ringbuffer {
+	struct prb_desc_ring	desc_ring;
+	struct prb_data_ring	text_data_ring;
+	atomic_long_t		fail;
+};
+
+/*
+ * Used by writers as a reserve/commit handle.
+ *
+ * @rb:         Ringbuffer where the entry is reserved.
+ * @irqflags:   Saved irq flags to restore on entry commit.
+ * @id:         ID of the reserved descriptor.
+ * @text_space: Total occupied buffer space in the text data ring, including
+ *              ID, alignment padding, and wrapping data blocks.
+ *
+ * This structure is an opaque handle for writers. Its contents are only
+ * to be used by the ringbuffer implementation.
+ */
+struct prb_reserved_entry {
+	struct printk_ringbuffer	*rb;
+	unsigned long			irqflags;
+	unsigned long			id;
+	unsigned int			text_space;
+};
+
+/* The possible responses of a descriptor state-query. */
+enum desc_state {
+	desc_miss	=  -1,	/* ID mismatch (pseudo state) */
+	desc_reserved	= 0x0,	/* reserved, in use by writer */
+	desc_committed	= 0x1,	/* committed by writer, could get reopened */
+	desc_finalized	= 0x2,	/* committed, no further modification allowed */
+	desc_reusable	= 0x3,	/* free, not yet used by any writer */
+};
+
+#define _DATA_SIZE(sz_bits)	(1UL << (sz_bits))
+#define _DESCS_COUNT(ct_bits)	(1U << (ct_bits))
+#define DESC_SV_BITS		(sizeof(unsigned long) * 8)
+#define DESC_FLAGS_SHIFT	(DESC_SV_BITS - 2)
+#define DESC_FLAGS_MASK		(3UL << DESC_FLAGS_SHIFT)
+#define DESC_STATE(sv)		(3UL & (sv >> DESC_FLAGS_SHIFT))
+#define DESC_SV(id, state)	(((unsigned long)state << DESC_FLAGS_SHIFT) | id)
+#define DESC_ID_MASK		(~DESC_FLAGS_MASK)
+#define DESC_ID(sv)		((sv) & DESC_ID_MASK)
+#define FAILED_LPOS		0x1
+#define NO_LPOS			0x3
+
+#define FAILED_BLK_LPOS	\
+{				\
+	.begin	= FAILED_LPOS,	\
+	.next	= FAILED_LPOS,	\
+}
+
+/*
+ * Descriptor Bootstrap
+ *
+ * The descriptor array is minimally initialized to allow immediate usage
+ * by readers and writers. The requirements that the descriptor array
+ * initialization must satisfy:
+ *
+ *   Req1
+ *     The tail must point to an existing (committed or reusable) descriptor.
+ *     This is required by the implementation of prb_first_seq().
+ *
+ *   Req2
+ *     Readers must see that the ringbuffer is initially empty.
+ *
+ *   Req3
+ *     The first record reserved by a writer is assigned sequence number 0.
+ *
+ * To satisfy Req1, the tail initially points to a descriptor that is
+ * minimally initialized (having no data block, i.e. data-less with the
+ * data block's lpos @begin and @next values set to FAILED_LPOS).
+ *
+ * To satisfy Req2, the initial tail descriptor is initialized to the
+ * reusable state. Readers recognize reusable descriptors as existing
+ * records, but skip over them.
+ *
+ * To satisfy Req3, the last descriptor in the array is used as the initial
+ * head (and tail) descriptor. This allows the first record reserved by a
+ * writer (head + 1) to be the first descriptor in the array. (Only the first
+ * descriptor in the array could have a valid sequence number of 0.)
+ *
+ * The first time a descriptor is reserved, it is assigned a sequence number
+ * with the value of the array index. A "first time reserved" descriptor can
+ * be recognized because it has a sequence number of 0 but does not have an
+ * index of 0. (Only the first descriptor in the array could have a valid
+ * sequence number of 0.) After the first reservation, all future reservations
+ * (recycling) simply involve incrementing the sequence number by the array
+ * count.
+ *
+ *   Hack #1
+ *     Only the first descriptor in the array is allowed to have the sequence
+ *     number 0. In this case it is not possible to recognize if it is being
+ *     reserved the first time (set to index value) or has been reserved
+ *     previously (increment by the array count). This is handled by _always_
+ *     incrementing the sequence number by the array count when reserving the
+ *     first descriptor in the array. In order to satisfy Req3, the sequence
+ *     number of the first descriptor in the array is initialized to minus
+ *     the array count. Then, upon the first reservation, it is incremented
+ *     to 0, thus satisfying Req3.
+ *
+ *   Hack #2
+ *     prb_first_seq() can be called at any time by readers to retrieve the
+ *     sequence number of the tail descriptor. However, due to Req2 and Req3,
+ *     initially there are no records to report the sequence number of
+ *     (sequence numbers are u64 and there is nothing less than 0). To handle
+ *     this, the sequence number of the initial tail descriptor is initialized
+ *     to 0. Technically this is incorrect, because there is no record with
+ *     sequence number 0 (yet) and the tail descriptor is not the first
+ *     descriptor in the array. But it allows prb_read_valid() to correctly
+ *     report the existence of a record for _any_ given sequence number at all
+ *     times. Bootstrapping is complete when the tail is pushed the first
+ *     time, thus finally pointing to the first descriptor reserved by a
+ *     writer, which has the assigned sequence number 0.
+ */
+
+/*
+ * Initiating Logical Value Overflows
+ *
+ * Both logical position (lpos) and ID values can be mapped to array indexes
+ * but may experience overflows during the lifetime of the system. To ensure
+ * that printk_ringbuffer can handle the overflows for these types, initial
+ * values are chosen that map to the correct initial array indexes, but will
+ * result in overflows soon.
+ *
+ *   BLK0_LPOS
+ *     The initial @head_lpos and @tail_lpos for data rings. It is at index
+ *     0 and the lpos value is such that it will overflow on the first wrap.
+ *
+ *   DESC0_ID
+ *     The initial @head_id and @tail_id for the desc ring. It is at the last
+ *     index of the descriptor array (see Req3 above) and the ID value is such
+ *     that it will overflow on the second wrap.
+ */
+#define BLK0_LPOS(sz_bits)	(-(_DATA_SIZE(sz_bits)))
+#define DESC0_ID(ct_bits)	DESC_ID(-(_DESCS_COUNT(ct_bits) + 1))
+#define DESC0_SV(ct_bits)	DESC_SV(DESC0_ID(ct_bits), desc_reusable)
+
+/*
+ * Define a ringbuffer with an external text data buffer. The same as
+ * DEFINE_PRINTKRB() but requires specifying an external buffer for the
+ * text data.
+ *
+ * Note: The specified external buffer must be of the size:
+ *       2 ^ (descbits + avgtextbits)
+ */
+#define _DEFINE_PRINTKRB(name, descbits, avgtextbits, text_buf)			\
+static struct prb_desc _##name##_descs[_DESCS_COUNT(descbits)] = {				\
+	/* the initial head and tail */								\
+	[_DESCS_COUNT(descbits) - 1] = {							\
+		/* reusable */									\
+		.state_var	= ATOMIC_INIT(DESC0_SV(descbits)),				\
+		/* no associated data block */							\
+		.text_blk_lpos	= FAILED_BLK_LPOS,						\
+	},											\
+};												\
+static struct printk_info _##name##_infos[_DESCS_COUNT(descbits)] = {				\
+	/* this will be the first record reserved by a writer */				\
+	[0] = {											\
+		/* will be incremented to 0 on the first reservation */				\
+		.seq = -(u64)_DESCS_COUNT(descbits),						\
+	},											\
+	/* the initial head and tail */								\
+	[_DESCS_COUNT(descbits) - 1] = {							\
+		/* reports the first seq value during the bootstrap phase */			\
+		.seq = 0,									\
+	},											\
+};												\
+static struct printk_ringbuffer name = {							\
+	.desc_ring = {										\
+		.count_bits	= descbits,							\
+		.descs		= &_##name##_descs[0],						\
+		.infos		= &_##name##_infos[0],						\
+		.head_id	= ATOMIC_INIT(DESC0_ID(descbits)),				\
+		.tail_id	= ATOMIC_INIT(DESC0_ID(descbits)),				\
+		.last_finalized_id = ATOMIC_INIT(DESC0_ID(descbits)),				\
+	},											\
+	.text_data_ring = {									\
+		.size_bits	= (avgtextbits) + (descbits),					\
+		.data		= text_buf,							\
+		.head_lpos	= ATOMIC_LONG_INIT(BLK0_LPOS((avgtextbits) + (descbits))),	\
+		.tail_lpos	= ATOMIC_LONG_INIT(BLK0_LPOS((avgtextbits) + (descbits))),	\
+	},											\
+	.fail			= ATOMIC_LONG_INIT(0),						\
+}
+
+/**
+ * DEFINE_PRINTKRB() - Define a ringbuffer.
+ *
+ * @name:        The name of the ringbuffer variable.
+ * @descbits:    The number of descriptors as a power-of-2 value.
+ * @avgtextbits: The average text data size per record as a power-of-2 value.
+ *
+ * This is a macro for defining a ringbuffer and all internal structures
+ * such that it is ready for immediate use. See _DEFINE_PRINTKRB() for a
+ * variant where the text data buffer can be specified externally.
+ */
+#define DEFINE_PRINTKRB(name, descbits, avgtextbits)				\
+static char _##name##_text[1U << ((avgtextbits) + (descbits))]			\
+			__aligned(__alignof__(unsigned long));			\
+_DEFINE_PRINTKRB(name, descbits, avgtextbits, &_##name##_text[0])
+
+/* Writer Interface */
+
+/**
+ * prb_rec_init_wr() - Initialize a buffer for writing records.
+ *
+ * @r:             The record to initialize.
+ * @text_buf_size: The needed text buffer size.
+ */
+static inline void prb_rec_init_wr(struct printk_record *r,
+				   unsigned int text_buf_size)
+{
+	r->info = NULL;
+	r->text_buf = NULL;
+	r->text_buf_size = text_buf_size;
+}
+
+bool prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb,
+		 struct printk_record *r);
+bool prb_reserve_in_last(struct prb_reserved_entry *e, struct printk_ringbuffer *rb,
+			 struct printk_record *r, u32 caller_id, unsigned int max_size);
+void prb_commit(struct prb_reserved_entry *e);
+void prb_final_commit(struct prb_reserved_entry *e);
+
+void prb_init(struct printk_ringbuffer *rb,
+	      char *text_buf, unsigned int text_buf_size,
+	      struct prb_desc *descs, unsigned int descs_count_bits,
+	      struct printk_info *infos);
+unsigned int prb_record_text_space(struct prb_reserved_entry *e);
+
+/* Reader Interface */
+
+/**
+ * prb_rec_init_rd() - Initialize a buffer for reading records.
+ *
+ * @r:             The record to initialize.
+ * @info:          A buffer to store record meta-data.
+ * @text_buf:      A buffer to store text data.
+ * @text_buf_size: The size of @text_buf.
+ *
+ * Initialize all the fields that a reader is interested in. All arguments
+ * (except @r) are optional. Only record data for arguments that are
+ * non-NULL or non-zero will be read.
+ */
+static inline void prb_rec_init_rd(struct printk_record *r,
+				   struct printk_info *info,
+				   char *text_buf, unsigned int text_buf_size)
+{
+	r->info = info;
+	r->text_buf = text_buf;
+	r->text_buf_size = text_buf_size;
+}
+
+/**
+ * prb_for_each_record() - Iterate over the records of a ringbuffer.
+ *
+ * @from: The sequence number to begin with.
+ * @rb:   The ringbuffer to iterate over.
+ * @s:    A u64 to store the sequence number on each iteration.
+ * @r:    A printk_record to store the record on each iteration.
+ *
+ * This is a macro for conveniently iterating over a ringbuffer.
+ * Note that @s may not be the sequence number of the record on each
+ * iteration. For the sequence number, @r->info->seq should be checked.
+ *
+ * Context: Any context.
+ */
+#define prb_for_each_record(from, rb, s, r) \
+for ((s) = from; prb_read_valid(rb, s, r); (s) = (r)->info->seq + 1)
+
+/**
+ * prb_for_each_info() - Iterate over the meta data of a ringbuffer.
+ *
+ * @from: The sequence number to begin with.
+ * @rb:   The ringbuffer to iterate over.
+ * @s:    A u64 to store the sequence number on each iteration.
+ * @i:    A printk_info to store the record meta data on each iteration.
+ * @lc:   An unsigned int to store the text line count of each record.
+ *
+ * This is a macro for conveniently iterating over a ringbuffer.
+ * Note that @s may not be the sequence number of the record on each
+ * iteration. For the sequence number, @r->info->seq should be checked.
+ *
+ * Context: Any context.
+ */
+#define prb_for_each_info(from, rb, s, i, lc) \
+for ((s) = from; prb_read_valid_info(rb, s, i, lc); (s) = (i)->seq + 1)
+
+bool prb_read_valid(struct printk_ringbuffer *rb, u64 seq,
+		    struct printk_record *r);
+bool prb_read_valid_info(struct printk_ringbuffer *rb, u64 seq,
+			 struct printk_info *info, unsigned int *line_count);
+
+u64 prb_first_valid_seq(struct printk_ringbuffer *rb);
+u64 prb_next_seq(struct printk_ringbuffer *rb);
+
+#endif /* _KERNEL_PRINTK_RINGBUFFER_H */
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
new file mode 100644
index 000000000..6d10927a0
--- /dev/null
+++ b/kernel/printk/printk_safe.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * printk_safe.c - Safe printk for printk-deadlock-prone contexts
+ */
+
+#include <linux/preempt.h>
+#include <linux/kdb.h>
+#include <linux/smp.h>
+#include <linux/cpumask.h>
+#include <linux/printk.h>
+#include <linux/kprobes.h>
+
+#include "internal.h"
+
+static DEFINE_PER_CPU(int, printk_context);
+
+/* Can be preempted by NMI. */
+void __printk_safe_enter(void)
+{
+	this_cpu_inc(printk_context);
+}
+
+/* Can be preempted by NMI. */
+void __printk_safe_exit(void)
+{
+	this_cpu_dec(printk_context);
+}
+
+asmlinkage int vprintk(const char *fmt, va_list args)
+{
+#ifdef CONFIG_KGDB_KDB
+	/* Allow to pass printk() to kdb but avoid a recursion. */
+	if (unlikely(kdb_trap_printk && kdb_printf_cpu < 0))
+		return vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args);
+#endif
+
+	/*
+	 * Use the main logbuf even in NMI. But avoid calling console
+	 * drivers that might have their own locks.
+	 */
+	if (this_cpu_read(printk_context) || in_nmi())
+		return vprintk_deferred(fmt, args);
+
+	/* No obstacles. */
+	return vprintk_default(fmt, args);
+}
+EXPORT_SYMBOL(vprintk);
diff --git a/kernel/printk/sysctl.c b/kernel/printk/sysctl.c
new file mode 100644
index 000000000..c228343ee
--- /dev/null
+++ b/kernel/printk/sysctl.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sysctl.c: General linux system control interface
+ */
+
+#include <linux/sysctl.h>
+#include <linux/printk.h>
+#include <linux/capability.h>
+#include <linux/ratelimit.h>
+#include "internal.h"
+
+static const int ten_thousand = 10000;
+
+static int proc_dointvec_minmax_sysadmin(struct ctl_table *table, int write,
+				void *buffer, size_t *lenp, loff_t *ppos)
+{
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+}
+
+static struct ctl_table printk_sysctls[] = {
+	{
+		.procname	= "printk",
+		.data		= &console_loglevel,
+		.maxlen		= 4*sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "printk_ratelimit",
+		.data		= &printk_ratelimit_state.interval,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_jiffies,
+	},
+	{
+		.procname	= "printk_ratelimit_burst",
+		.data		= &printk_ratelimit_state.burst,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "printk_delay",
+		.data		= &printk_delay_msec,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= (void *)&ten_thousand,
+	},
+	{
+		.procname	= "printk_devkmsg",
+		.data		= devkmsg_log_str,
+		.maxlen		= DEVKMSG_STR_MAX_SIZE,
+		.mode		= 0644,
+		.proc_handler	= devkmsg_sysctl_set_loglvl,
+	},
+	{
+		.procname	= "dmesg_restrict",
+		.data		= &dmesg_restrict,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax_sysadmin,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "kptr_restrict",
+		.data		= &kptr_restrict,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax_sysadmin,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_TWO,
+	},
+	{}
+};
+
+void __init printk_sysctl_init(void)
+{
+	register_sysctl_init("kernel", printk_sysctls);
+}
diff --git a/kernel/profile.c b/kernel/profile.c
new file mode 100644
index 000000000..8a77769bc
--- /dev/null
+++ b/kernel/profile.c
@@ -0,0 +1,501 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/kernel/profile.c
+ *  Simple profiling. Manages a direct-mapped profile hit count buffer,
+ *  with configurable resolution, support for restricting the cpus on
+ *  which profiling is done, and switching between cpu time and
+ *  schedule() calls via kernel command line parameters passed at boot.
+ *
+ *  Scheduler profiling support, Arjan van de Ven and Ingo Molnar,
+ *	Red Hat, July 2004
+ *  Consolidation of architecture support code for profiling,
+ *	Nadia Yvette Chambers, Oracle, July 2004
+ *  Amortized hit count accounting via per-cpu open-addressed hashtables
+ *	to resolve timer interrupt livelocks, Nadia Yvette Chambers,
+ *	Oracle, 2004
+ */
+
+#include <linux/export.h>
+#include <linux/profile.h>
+#include <linux/memblock.h>
+#include <linux/notifier.h>
+#include <linux/mm.h>
+#include <linux/cpumask.h>
+#include <linux/cpu.h>
+#include <linux/highmem.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/sched/stat.h>
+
+#include <asm/sections.h>
+#include <asm/irq_regs.h>
+#include <asm/ptrace.h>
+
+struct profile_hit {
+	u32 pc, hits;
+};
+#define PROFILE_GRPSHIFT	3
+#define PROFILE_GRPSZ		(1 << PROFILE_GRPSHIFT)
+#define NR_PROFILE_HIT		(PAGE_SIZE/sizeof(struct profile_hit))
+#define NR_PROFILE_GRP		(NR_PROFILE_HIT/PROFILE_GRPSZ)
+
+static atomic_t *prof_buffer;
+static unsigned long prof_len;
+static unsigned short int prof_shift;
+
+int prof_on __read_mostly;
+EXPORT_SYMBOL_GPL(prof_on);
+
+static cpumask_var_t prof_cpu_mask;
+#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
+static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
+static DEFINE_PER_CPU(int, cpu_profile_flip);
+static DEFINE_MUTEX(profile_flip_mutex);
+#endif /* CONFIG_SMP */
+
+int profile_setup(char *str)
+{
+	static const char schedstr[] = "schedule";
+	static const char sleepstr[] = "sleep";
+	static const char kvmstr[] = "kvm";
+	const char *select = NULL;
+	int par;
+
+	if (!strncmp(str, sleepstr, strlen(sleepstr))) {
+#ifdef CONFIG_SCHEDSTATS
+		force_schedstat_enabled();
+		prof_on = SLEEP_PROFILING;
+		select = sleepstr;
+#else
+		pr_warn("kernel sleep profiling requires CONFIG_SCHEDSTATS\n");
+#endif /* CONFIG_SCHEDSTATS */
+	} else if (!strncmp(str, schedstr, strlen(schedstr))) {
+		prof_on = SCHED_PROFILING;
+		select = schedstr;
+	} else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
+		prof_on = KVM_PROFILING;
+		select = kvmstr;
+	} else if (get_option(&str, &par)) {
+		prof_shift = clamp(par, 0, BITS_PER_LONG - 1);
+		prof_on = CPU_PROFILING;
+		pr_info("kernel profiling enabled (shift: %u)\n",
+			prof_shift);
+	}
+
+	if (select) {
+		if (str[strlen(select)] == ',')
+			str += strlen(select) + 1;
+		if (get_option(&str, &par))
+			prof_shift = clamp(par, 0, BITS_PER_LONG - 1);
+		pr_info("kernel %s profiling enabled (shift: %u)\n",
+			select, prof_shift);
+	}
+
+	return 1;
+}
+__setup("profile=", profile_setup);
+
+
+int __ref profile_init(void)
+{
+	int buffer_bytes;
+	if (!prof_on)
+		return 0;
+
+	/* only text is profiled */
+	prof_len = (_etext - _stext) >> prof_shift;
+
+	if (!prof_len) {
+		pr_warn("profiling shift: %u too large\n", prof_shift);
+		prof_on = 0;
+		return -EINVAL;
+	}
+
+	buffer_bytes = prof_len*sizeof(atomic_t);
+
+	if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	cpumask_copy(prof_cpu_mask, cpu_possible_mask);
+
+	prof_buffer = kzalloc(buffer_bytes, GFP_KERNEL|__GFP_NOWARN);
+	if (prof_buffer)
+		return 0;
+
+	prof_buffer = alloc_pages_exact(buffer_bytes,
+					GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN);
+	if (prof_buffer)
+		return 0;
+
+	prof_buffer = vzalloc(buffer_bytes);
+	if (prof_buffer)
+		return 0;
+
+	free_cpumask_var(prof_cpu_mask);
+	return -ENOMEM;
+}
+
+#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
+/*
+ * Each cpu has a pair of open-addressed hashtables for pending
+ * profile hits. read_profile() IPI's all cpus to request them
+ * to flip buffers and flushes their contents to prof_buffer itself.
+ * Flip requests are serialized by the profile_flip_mutex. The sole
+ * use of having a second hashtable is for avoiding cacheline
+ * contention that would otherwise happen during flushes of pending
+ * profile hits required for the accuracy of reported profile hits
+ * and so resurrect the interrupt livelock issue.
+ *
+ * The open-addressed hashtables are indexed by profile buffer slot
+ * and hold the number of pending hits to that profile buffer slot on
+ * a cpu in an entry. When the hashtable overflows, all pending hits
+ * are accounted to their corresponding profile buffer slots with
+ * atomic_add() and the hashtable emptied. As numerous pending hits
+ * may be accounted to a profile buffer slot in a hashtable entry,
+ * this amortizes a number of atomic profile buffer increments likely
+ * to be far larger than the number of entries in the hashtable,
+ * particularly given that the number of distinct profile buffer
+ * positions to which hits are accounted during short intervals (e.g.
+ * several seconds) is usually very small. Exclusion from buffer
+ * flipping is provided by interrupt disablement (note that for
+ * SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from
+ * process context).
+ * The hash function is meant to be lightweight as opposed to strong,
+ * and was vaguely inspired by ppc64 firmware-supported inverted
+ * pagetable hash functions, but uses a full hashtable full of finite
+ * collision chains, not just pairs of them.
+ *
+ * -- nyc
+ */
+static void __profile_flip_buffers(void *unused)
+{
+	int cpu = smp_processor_id();
+
+	per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu);
+}
+
+static void profile_flip_buffers(void)
+{
+	int i, j, cpu;
+
+	mutex_lock(&profile_flip_mutex);
+	j = per_cpu(cpu_profile_flip, get_cpu());
+	put_cpu();
+	on_each_cpu(__profile_flip_buffers, NULL, 1);
+	for_each_online_cpu(cpu) {
+		struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j];
+		for (i = 0; i < NR_PROFILE_HIT; ++i) {
+			if (!hits[i].hits) {
+				if (hits[i].pc)
+					hits[i].pc = 0;
+				continue;
+			}
+			atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
+			hits[i].hits = hits[i].pc = 0;
+		}
+	}
+	mutex_unlock(&profile_flip_mutex);
+}
+
+static void profile_discard_flip_buffers(void)
+{
+	int i, cpu;
+
+	mutex_lock(&profile_flip_mutex);
+	i = per_cpu(cpu_profile_flip, get_cpu());
+	put_cpu();
+	on_each_cpu(__profile_flip_buffers, NULL, 1);
+	for_each_online_cpu(cpu) {
+		struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i];
+		memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit));
+	}
+	mutex_unlock(&profile_flip_mutex);
+}
+
+static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
+{
+	unsigned long primary, secondary, flags, pc = (unsigned long)__pc;
+	int i, j, cpu;
+	struct profile_hit *hits;
+
+	pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);
+	i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
+	secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
+	cpu = get_cpu();
+	hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)];
+	if (!hits) {
+		put_cpu();
+		return;
+	}
+	/*
+	 * We buffer the global profiler buffer into a per-CPU
+	 * queue and thus reduce the number of global (and possibly
+	 * NUMA-alien) accesses. The write-queue is self-coalescing:
+	 */
+	local_irq_save(flags);
+	do {
+		for (j = 0; j < PROFILE_GRPSZ; ++j) {
+			if (hits[i + j].pc == pc) {
+				hits[i + j].hits += nr_hits;
+				goto out;
+			} else if (!hits[i + j].hits) {
+				hits[i + j].pc = pc;
+				hits[i + j].hits = nr_hits;
+				goto out;
+			}
+		}
+		i = (i + secondary) & (NR_PROFILE_HIT - 1);
+	} while (i != primary);
+
+	/*
+	 * Add the current hit(s) and flush the write-queue out
+	 * to the global buffer:
+	 */
+	atomic_add(nr_hits, &prof_buffer[pc]);
+	for (i = 0; i < NR_PROFILE_HIT; ++i) {
+		atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
+		hits[i].pc = hits[i].hits = 0;
+	}
+out:
+	local_irq_restore(flags);
+	put_cpu();
+}
+
+static int profile_dead_cpu(unsigned int cpu)
+{
+	struct page *page;
+	int i;
+
+	if (cpumask_available(prof_cpu_mask))
+		cpumask_clear_cpu(cpu, prof_cpu_mask);
+
+	for (i = 0; i < 2; i++) {
+		if (per_cpu(cpu_profile_hits, cpu)[i]) {
+			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[i]);
+			per_cpu(cpu_profile_hits, cpu)[i] = NULL;
+			__free_page(page);
+		}
+	}
+	return 0;
+}
+
+static int profile_prepare_cpu(unsigned int cpu)
+{
+	int i, node = cpu_to_mem(cpu);
+	struct page *page;
+
+	per_cpu(cpu_profile_flip, cpu) = 0;
+
+	for (i = 0; i < 2; i++) {
+		if (per_cpu(cpu_profile_hits, cpu)[i])
+			continue;
+
+		page = __alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
+		if (!page) {
+			profile_dead_cpu(cpu);
+			return -ENOMEM;
+		}
+		per_cpu(cpu_profile_hits, cpu)[i] = page_address(page);
+
+	}
+	return 0;
+}
+
+static int profile_online_cpu(unsigned int cpu)
+{
+	if (cpumask_available(prof_cpu_mask))
+		cpumask_set_cpu(cpu, prof_cpu_mask);
+
+	return 0;
+}
+
+#else /* !CONFIG_SMP */
+#define profile_flip_buffers()		do { } while (0)
+#define profile_discard_flip_buffers()	do { } while (0)
+
+static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
+{
+	unsigned long pc;
+	pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
+	atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]);
+}
+#endif /* !CONFIG_SMP */
+
+void profile_hits(int type, void *__pc, unsigned int nr_hits)
+{
+	if (prof_on != type || !prof_buffer)
+		return;
+	do_profile_hits(type, __pc, nr_hits);
+}
+EXPORT_SYMBOL_GPL(profile_hits);
+
+void profile_tick(int type)
+{
+	struct pt_regs *regs = get_irq_regs();
+
+	if (!user_mode(regs) && cpumask_available(prof_cpu_mask) &&
+	    cpumask_test_cpu(smp_processor_id(), prof_cpu_mask))
+		profile_hit(type, (void *)profile_pc(regs));
+}
+
+#ifdef CONFIG_PROC_FS
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/uaccess.h>
+
+static int prof_cpu_mask_proc_show(struct seq_file *m, void *v)
+{
+	seq_printf(m, "%*pb\n", cpumask_pr_args(prof_cpu_mask));
+	return 0;
+}
+
+static int prof_cpu_mask_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, prof_cpu_mask_proc_show, NULL);
+}
+
+static ssize_t prof_cpu_mask_proc_write(struct file *file,
+	const char __user *buffer, size_t count, loff_t *pos)
+{
+	cpumask_var_t new_value;
+	int err;
+
+	if (!zalloc_cpumask_var(&new_value, GFP_KERNEL))
+		return -ENOMEM;
+
+	err = cpumask_parse_user(buffer, count, new_value);
+	if (!err) {
+		cpumask_copy(prof_cpu_mask, new_value);
+		err = count;
+	}
+	free_cpumask_var(new_value);
+	return err;
+}
+
+static const struct proc_ops prof_cpu_mask_proc_ops = {
+	.proc_open	= prof_cpu_mask_proc_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= single_release,
+	.proc_write	= prof_cpu_mask_proc_write,
+};
+
+void create_prof_cpu_mask(void)
+{
+	/* create /proc/irq/prof_cpu_mask */
+	proc_create("irq/prof_cpu_mask", 0600, NULL, &prof_cpu_mask_proc_ops);
+}
+
+/*
+ * This function accesses profiling information. The returned data is
+ * binary: the sampling step and the actual contents of the profile
+ * buffer. Use of the program readprofile is recommended in order to
+ * get meaningful info out of these data.
+ */
+static ssize_t
+read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+	unsigned long p = *ppos;
+	ssize_t read;
+	char *pnt;
+	unsigned long sample_step = 1UL << prof_shift;
+
+	profile_flip_buffers();
+	if (p >= (prof_len+1)*sizeof(unsigned int))
+		return 0;
+	if (count > (prof_len+1)*sizeof(unsigned int) - p)
+		count = (prof_len+1)*sizeof(unsigned int) - p;
+	read = 0;
+
+	while (p < sizeof(unsigned int) && count > 0) {
+		if (put_user(*((char *)(&sample_step)+p), buf))
+			return -EFAULT;
+		buf++; p++; count--; read++;
+	}
+	pnt = (char *)prof_buffer + p - sizeof(atomic_t);
+	if (copy_to_user(buf, (void *)pnt, count))
+		return -EFAULT;
+	read += count;
+	*ppos += read;
+	return read;
+}
+
+/* default is to not implement this call */
+int __weak setup_profiling_timer(unsigned mult)
+{
+	return -EINVAL;
+}
+
+/*
+ * Writing to /proc/profile resets the counters
+ *
+ * Writing a 'profiling multiplier' value into it also re-sets the profiling
+ * interrupt frequency, on architectures that support this.
+ */
+static ssize_t write_profile(struct file *file, const char __user *buf,
+			     size_t count, loff_t *ppos)
+{
+#ifdef CONFIG_SMP
+	if (count == sizeof(int)) {
+		unsigned int multiplier;
+
+		if (copy_from_user(&multiplier, buf, sizeof(int)))
+			return -EFAULT;
+
+		if (setup_profiling_timer(multiplier))
+			return -EINVAL;
+	}
+#endif
+	profile_discard_flip_buffers();
+	memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
+	return count;
+}
+
+static const struct proc_ops profile_proc_ops = {
+	.proc_read	= read_profile,
+	.proc_write	= write_profile,
+	.proc_lseek	= default_llseek,
+};
+
+int __ref create_proc_profile(void)
+{
+	struct proc_dir_entry *entry;
+#ifdef CONFIG_SMP
+	enum cpuhp_state online_state;
+#endif
+
+	int err = 0;
+
+	if (!prof_on)
+		return 0;
+#ifdef CONFIG_SMP
+	err = cpuhp_setup_state(CPUHP_PROFILE_PREPARE, "PROFILE_PREPARE",
+				profile_prepare_cpu, profile_dead_cpu);
+	if (err)
+		return err;
+
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "AP_PROFILE_ONLINE",
+				profile_online_cpu, NULL);
+	if (err < 0)
+		goto err_state_prep;
+	online_state = err;
+	err = 0;
+#endif
+	entry = proc_create("profile", S_IWUSR | S_IRUGO,
+			    NULL, &profile_proc_ops);
+	if (!entry)
+		goto err_state_onl;
+	proc_set_size(entry, (1 + prof_len) * sizeof(atomic_t));
+
+	return err;
+err_state_onl:
+#ifdef CONFIG_SMP
+	cpuhp_remove_state(online_state);
+err_state_prep:
+	cpuhp_remove_state(CPUHP_PROFILE_PREPARE);
+#endif
+	return err;
+}
+subsys_initcall(create_proc_profile);
+#endif /* CONFIG_PROC_FS */
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
new file mode 100644
index 000000000..54482193e
--- /dev/null
+++ b/kernel/ptrace.c
@@ -0,0 +1,1443 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/kernel/ptrace.c
+ *
+ * (C) Copyright 1999 Linus Torvalds
+ *
+ * Common interfaces for "ptrace()" which we do not want
+ * to continually duplicate across every architecture.
+ */
+
+#include <linux/capability.h>
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/coredump.h>
+#include <linux/sched/task.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/pagemap.h>
+#include <linux/ptrace.h>
+#include <linux/security.h>
+#include <linux/signal.h>
+#include <linux/uio.h>
+#include <linux/audit.h>
+#include <linux/pid_namespace.h>
+#include <linux/syscalls.h>
+#include <linux/uaccess.h>
+#include <linux/regset.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/cn_proc.h>
+#include <linux/compat.h>
+#include <linux/sched/signal.h>
+#include <linux/minmax.h>
+
+#include <asm/syscall.h>	/* for syscall_get_* */
+
+/*
+ * Access another process' address space via ptrace.
+ * Source/target buffer must be kernel space,
+ * Do not walk the page table directly, use get_user_pages
+ */
+int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
+		     void *buf, int len, unsigned int gup_flags)
+{
+	struct mm_struct *mm;
+	int ret;
+
+	mm = get_task_mm(tsk);
+	if (!mm)
+		return 0;
+
+	if (!tsk->ptrace ||
+	    (current != tsk->parent) ||
+	    ((get_dumpable(mm) != SUID_DUMP_USER) &&
+	     !ptracer_capable(tsk, mm->user_ns))) {
+		mmput(mm);
+		return 0;
+	}
+
+	ret = __access_remote_vm(mm, addr, buf, len, gup_flags);
+	mmput(mm);
+
+	return ret;
+}
+
+
+void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
+		   const struct cred *ptracer_cred)
+{
+	BUG_ON(!list_empty(&child->ptrace_entry));
+	list_add(&child->ptrace_entry, &new_parent->ptraced);
+	child->parent = new_parent;
+	child->ptracer_cred = get_cred(ptracer_cred);
+}
+
+/*
+ * ptrace a task: make the debugger its new parent and
+ * move it to the ptrace list.
+ *
+ * Must be called with the tasklist lock write-held.
+ */
+static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
+{
+	__ptrace_link(child, new_parent, current_cred());
+}
+
+/**
+ * __ptrace_unlink - unlink ptracee and restore its execution state
+ * @child: ptracee to be unlinked
+ *
+ * Remove @child from the ptrace list, move it back to the original parent,
+ * and restore the execution state so that it conforms to the group stop
+ * state.
+ *
+ * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
+ * exiting.  For PTRACE_DETACH, unless the ptracee has been killed between
+ * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
+ * If the ptracer is exiting, the ptracee can be in any state.
+ *
+ * After detach, the ptracee should be in a state which conforms to the
+ * group stop.  If the group is stopped or in the process of stopping, the
+ * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
+ * up from TASK_TRACED.
+ *
+ * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
+ * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
+ * to but in the opposite direction of what happens while attaching to a
+ * stopped task.  However, in this direction, the intermediate RUNNING
+ * state is not hidden even from the current ptracer and if it immediately
+ * re-attaches and performs a WNOHANG wait(2), it may fail.
+ *
+ * CONTEXT:
+ * write_lock_irq(tasklist_lock)
+ */
+void __ptrace_unlink(struct task_struct *child)
+{
+	const struct cred *old_cred;
+	BUG_ON(!child->ptrace);
+
+	clear_task_syscall_work(child, SYSCALL_TRACE);
+#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
+	clear_task_syscall_work(child, SYSCALL_EMU);
+#endif
+
+	child->parent = child->real_parent;
+	list_del_init(&child->ptrace_entry);
+	old_cred = child->ptracer_cred;
+	child->ptracer_cred = NULL;
+	put_cred(old_cred);
+
+	spin_lock(&child->sighand->siglock);
+	child->ptrace = 0;
+	/*
+	 * Clear all pending traps and TRAPPING.  TRAPPING should be
+	 * cleared regardless of JOBCTL_STOP_PENDING.  Do it explicitly.
+	 */
+	task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
+	task_clear_jobctl_trapping(child);
+
+	/*
+	 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
+	 * @child isn't dead.
+	 */
+	if (!(child->flags & PF_EXITING) &&
+	    (child->signal->flags & SIGNAL_STOP_STOPPED ||
+	     child->signal->group_stop_count)) {
+		child->jobctl |= JOBCTL_STOP_PENDING;
+
+		/*
+		 * This is only possible if this thread was cloned by the
+		 * traced task running in the stopped group, set the signal
+		 * for the future reports.
+		 * FIXME: we should change ptrace_init_task() to handle this
+		 * case.
+		 */
+		if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
+			child->jobctl |= SIGSTOP;
+	}
+
+	/*
+	 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
+	 * @child in the butt.  Note that @resume should be used iff @child
+	 * is in TASK_TRACED; otherwise, we might unduly disrupt
+	 * TASK_KILLABLE sleeps.
+	 */
+	if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
+		ptrace_signal_wake_up(child, true);
+
+	spin_unlock(&child->sighand->siglock);
+}
+
+static bool looks_like_a_spurious_pid(struct task_struct *task)
+{
+	if (task->exit_code != ((PTRACE_EVENT_EXEC << 8) | SIGTRAP))
+		return false;
+
+	if (task_pid_vnr(task) == task->ptrace_message)
+		return false;
+	/*
+	 * The tracee changed its pid but the PTRACE_EVENT_EXEC event
+	 * was not wait()'ed, most probably debugger targets the old
+	 * leader which was destroyed in de_thread().
+	 */
+	return true;
+}
+
+/*
+ * Ensure that nothing can wake it up, even SIGKILL
+ *
+ * A task is switched to this state while a ptrace operation is in progress;
+ * such that the ptrace operation is uninterruptible.
+ */
+static bool ptrace_freeze_traced(struct task_struct *task)
+{
+	bool ret = false;
+
+	/* Lockless, nobody but us can set this flag */
+	if (task->jobctl & JOBCTL_LISTENING)
+		return ret;
+
+	spin_lock_irq(&task->sighand->siglock);
+	if (task_is_traced(task) && !looks_like_a_spurious_pid(task) &&
+	    !__fatal_signal_pending(task)) {
+		task->jobctl |= JOBCTL_PTRACE_FROZEN;
+		ret = true;
+	}
+	spin_unlock_irq(&task->sighand->siglock);
+
+	return ret;
+}
+
+static void ptrace_unfreeze_traced(struct task_struct *task)
+{
+	unsigned long flags;
+
+	/*
+	 * The child may be awake and may have cleared
+	 * JOBCTL_PTRACE_FROZEN (see ptrace_resume).  The child will
+	 * not set JOBCTL_PTRACE_FROZEN or enter __TASK_TRACED anew.
+	 */
+	if (lock_task_sighand(task, &flags)) {
+		task->jobctl &= ~JOBCTL_PTRACE_FROZEN;
+		if (__fatal_signal_pending(task)) {
+			task->jobctl &= ~JOBCTL_TRACED;
+			wake_up_state(task, __TASK_TRACED);
+		}
+		unlock_task_sighand(task, &flags);
+	}
+}
+
+/**
+ * ptrace_check_attach - check whether ptracee is ready for ptrace operation
+ * @child: ptracee to check for
+ * @ignore_state: don't check whether @child is currently %TASK_TRACED
+ *
+ * Check whether @child is being ptraced by %current and ready for further
+ * ptrace operations.  If @ignore_state is %false, @child also should be in
+ * %TASK_TRACED state and on return the child is guaranteed to be traced
+ * and not executing.  If @ignore_state is %true, @child can be in any
+ * state.
+ *
+ * CONTEXT:
+ * Grabs and releases tasklist_lock and @child->sighand->siglock.
+ *
+ * RETURNS:
+ * 0 on success, -ESRCH if %child is not ready.
+ */
+static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
+{
+	int ret = -ESRCH;
+
+	/*
+	 * We take the read lock around doing both checks to close a
+	 * possible race where someone else was tracing our child and
+	 * detached between these two checks.  After this locked check,
+	 * we are sure that this is our traced child and that can only
+	 * be changed by us so it's not changing right after this.
+	 */
+	read_lock(&tasklist_lock);
+	if (child->ptrace && child->parent == current) {
+		/*
+		 * child->sighand can't be NULL, release_task()
+		 * does ptrace_unlink() before __exit_signal().
+		 */
+		if (ignore_state || ptrace_freeze_traced(child))
+			ret = 0;
+	}
+	read_unlock(&tasklist_lock);
+
+	if (!ret && !ignore_state &&
+	    WARN_ON_ONCE(!wait_task_inactive(child, __TASK_TRACED|TASK_FROZEN)))
+		ret = -ESRCH;
+
+	return ret;
+}
+
+static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
+{
+	if (mode & PTRACE_MODE_NOAUDIT)
+		return ns_capable_noaudit(ns, CAP_SYS_PTRACE);
+	return ns_capable(ns, CAP_SYS_PTRACE);
+}
+
+/* Returns 0 on success, -errno on denial. */
+static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
+{
+	const struct cred *cred = current_cred(), *tcred;
+	struct mm_struct *mm;
+	kuid_t caller_uid;
+	kgid_t caller_gid;
+
+	if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
+		WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
+		return -EPERM;
+	}
+
+	/* May we inspect the given task?
+	 * This check is used both for attaching with ptrace
+	 * and for allowing access to sensitive information in /proc.
+	 *
+	 * ptrace_attach denies several cases that /proc allows
+	 * because setting up the necessary parent/child relationship
+	 * or halting the specified task is impossible.
+	 */
+
+	/* Don't let security modules deny introspection */
+	if (same_thread_group(task, current))
+		return 0;
+	rcu_read_lock();
+	if (mode & PTRACE_MODE_FSCREDS) {
+		caller_uid = cred->fsuid;
+		caller_gid = cred->fsgid;
+	} else {
+		/*
+		 * Using the euid would make more sense here, but something
+		 * in userland might rely on the old behavior, and this
+		 * shouldn't be a security problem since
+		 * PTRACE_MODE_REALCREDS implies that the caller explicitly
+		 * used a syscall that requests access to another process
+		 * (and not a filesystem syscall to procfs).
+		 */
+		caller_uid = cred->uid;
+		caller_gid = cred->gid;
+	}
+	tcred = __task_cred(task);
+	if (uid_eq(caller_uid, tcred->euid) &&
+	    uid_eq(caller_uid, tcred->suid) &&
+	    uid_eq(caller_uid, tcred->uid)  &&
+	    gid_eq(caller_gid, tcred->egid) &&
+	    gid_eq(caller_gid, tcred->sgid) &&
+	    gid_eq(caller_gid, tcred->gid))
+		goto ok;
+	if (ptrace_has_cap(tcred->user_ns, mode))
+		goto ok;
+	rcu_read_unlock();
+	return -EPERM;
+ok:
+	rcu_read_unlock();
+	/*
+	 * If a task drops privileges and becomes nondumpable (through a syscall
+	 * like setresuid()) while we are trying to access it, we must ensure
+	 * that the dumpability is read after the credentials; otherwise,
+	 * we may be able to attach to a task that we shouldn't be able to
+	 * attach to (as if the task had dropped privileges without becoming
+	 * nondumpable).
+	 * Pairs with a write barrier in commit_creds().
+	 */
+	smp_rmb();
+	mm = task->mm;
+	if (mm &&
+	    ((get_dumpable(mm) != SUID_DUMP_USER) &&
+	     !ptrace_has_cap(mm->user_ns, mode)))
+	    return -EPERM;
+
+	return security_ptrace_access_check(task, mode);
+}
+
+bool ptrace_may_access(struct task_struct *task, unsigned int mode)
+{
+	int err;
+	task_lock(task);
+	err = __ptrace_may_access(task, mode);
+	task_unlock(task);
+	return !err;
+}
+
+static int check_ptrace_options(unsigned long data)
+{
+	if (data & ~(unsigned long)PTRACE_O_MASK)
+		return -EINVAL;
+
+	if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
+		if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
+		    !IS_ENABLED(CONFIG_SECCOMP))
+			return -EINVAL;
+
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+
+		if (seccomp_mode(&current->seccomp) != SECCOMP_MODE_DISABLED ||
+		    current->ptrace & PT_SUSPEND_SECCOMP)
+			return -EPERM;
+	}
+	return 0;
+}
+
+static int ptrace_attach(struct task_struct *task, long request,
+			 unsigned long addr,
+			 unsigned long flags)
+{
+	bool seize = (request == PTRACE_SEIZE);
+	int retval;
+
+	retval = -EIO;
+	if (seize) {
+		if (addr != 0)
+			goto out;
+		/*
+		 * This duplicates the check in check_ptrace_options() because
+		 * ptrace_attach() and ptrace_setoptions() have historically
+		 * used different error codes for unknown ptrace options.
+		 */
+		if (flags & ~(unsigned long)PTRACE_O_MASK)
+			goto out;
+		retval = check_ptrace_options(flags);
+		if (retval)
+			return retval;
+		flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
+	} else {
+		flags = PT_PTRACED;
+	}
+
+	audit_ptrace(task);
+
+	retval = -EPERM;
+	if (unlikely(task->flags & PF_KTHREAD))
+		goto out;
+	if (same_thread_group(task, current))
+		goto out;
+
+	/*
+	 * Protect exec's credential calculations against our interference;
+	 * SUID, SGID and LSM creds get determined differently
+	 * under ptrace.
+	 */
+	retval = -ERESTARTNOINTR;
+	if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
+		goto out;
+
+	task_lock(task);
+	retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
+	task_unlock(task);
+	if (retval)
+		goto unlock_creds;
+
+	write_lock_irq(&tasklist_lock);
+	retval = -EPERM;
+	if (unlikely(task->exit_state))
+		goto unlock_tasklist;
+	if (task->ptrace)
+		goto unlock_tasklist;
+
+	task->ptrace = flags;
+
+	ptrace_link(task, current);
+
+	/* SEIZE doesn't trap tracee on attach */
+	if (!seize)
+		send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);
+
+	spin_lock(&task->sighand->siglock);
+
+	/*
+	 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
+	 * TRAPPING, and kick it so that it transits to TRACED.  TRAPPING
+	 * will be cleared if the child completes the transition or any
+	 * event which clears the group stop states happens.  We'll wait
+	 * for the transition to complete before returning from this
+	 * function.
+	 *
+	 * This hides STOPPED -> RUNNING -> TRACED transition from the
+	 * attaching thread but a different thread in the same group can
+	 * still observe the transient RUNNING state.  IOW, if another
+	 * thread's WNOHANG wait(2) on the stopped tracee races against
+	 * ATTACH, the wait(2) may fail due to the transient RUNNING.
+	 *
+	 * The following task_is_stopped() test is safe as both transitions
+	 * in and out of STOPPED are protected by siglock.
+	 */
+	if (task_is_stopped(task) &&
+	    task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) {
+		task->jobctl &= ~JOBCTL_STOPPED;
+		signal_wake_up_state(task, __TASK_STOPPED);
+	}
+
+	spin_unlock(&task->sighand->siglock);
+
+	retval = 0;
+unlock_tasklist:
+	write_unlock_irq(&tasklist_lock);
+unlock_creds:
+	mutex_unlock(&task->signal->cred_guard_mutex);
+out:
+	if (!retval) {
+		/*
+		 * We do not bother to change retval or clear JOBCTL_TRAPPING
+		 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
+		 * not return to user-mode, it will exit and clear this bit in
+		 * __ptrace_unlink() if it wasn't already cleared by the tracee;
+		 * and until then nobody can ptrace this task.
+		 */
+		wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
+		proc_ptrace_connector(task, PTRACE_ATTACH);
+	}
+
+	return retval;
+}
+
+/**
+ * ptrace_traceme  --  helper for PTRACE_TRACEME
+ *
+ * Performs checks and sets PT_PTRACED.
+ * Should be used by all ptrace implementations for PTRACE_TRACEME.
+ */
+static int ptrace_traceme(void)
+{
+	int ret = -EPERM;
+
+	write_lock_irq(&tasklist_lock);
+	/* Are we already being traced? */
+	if (!current->ptrace) {
+		ret = security_ptrace_traceme(current->parent);
+		/*
+		 * Check PF_EXITING to ensure ->real_parent has not passed
+		 * exit_ptrace(). Otherwise we don't report the error but
+		 * pretend ->real_parent untraces us right after return.
+		 */
+		if (!ret && !(current->real_parent->flags & PF_EXITING)) {
+			current->ptrace = PT_PTRACED;
+			ptrace_link(current, current->real_parent);
+		}
+	}
+	write_unlock_irq(&tasklist_lock);
+
+	return ret;
+}
+
+/*
+ * Called with irqs disabled, returns true if childs should reap themselves.
+ */
+static int ignoring_children(struct sighand_struct *sigh)
+{
+	int ret;
+	spin_lock(&sigh->siglock);
+	ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
+	      (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
+	spin_unlock(&sigh->siglock);
+	return ret;
+}
+
+/*
+ * Called with tasklist_lock held for writing.
+ * Unlink a traced task, and clean it up if it was a traced zombie.
+ * Return true if it needs to be reaped with release_task().
+ * (We can't call release_task() here because we already hold tasklist_lock.)
+ *
+ * If it's a zombie, our attachedness prevented normal parent notification
+ * or self-reaping.  Do notification now if it would have happened earlier.
+ * If it should reap itself, return true.
+ *
+ * If it's our own child, there is no notification to do. But if our normal
+ * children self-reap, then this child was prevented by ptrace and we must
+ * reap it now, in that case we must also wake up sub-threads sleeping in
+ * do_wait().
+ */
+static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
+{
+	bool dead;
+
+	__ptrace_unlink(p);
+
+	if (p->exit_state != EXIT_ZOMBIE)
+		return false;
+
+	dead = !thread_group_leader(p);
+
+	if (!dead && thread_group_empty(p)) {
+		if (!same_thread_group(p->real_parent, tracer))
+			dead = do_notify_parent(p, p->exit_signal);
+		else if (ignoring_children(tracer->sighand)) {
+			__wake_up_parent(p, tracer);
+			dead = true;
+		}
+	}
+	/* Mark it as in the process of being reaped. */
+	if (dead)
+		p->exit_state = EXIT_DEAD;
+	return dead;
+}
+
+static int ptrace_detach(struct task_struct *child, unsigned int data)
+{
+	if (!valid_signal(data))
+		return -EIO;
+
+	/* Architecture-specific hardware disable .. */
+	ptrace_disable(child);
+
+	write_lock_irq(&tasklist_lock);
+	/*
+	 * We rely on ptrace_freeze_traced(). It can't be killed and
+	 * untraced by another thread, it can't be a zombie.
+	 */
+	WARN_ON(!child->ptrace || child->exit_state);
+	/*
+	 * tasklist_lock avoids the race with wait_task_stopped(), see
+	 * the comment in ptrace_resume().
+	 */
+	child->exit_code = data;
+	__ptrace_detach(current, child);
+	write_unlock_irq(&tasklist_lock);
+
+	proc_ptrace_connector(child, PTRACE_DETACH);
+
+	return 0;
+}
+
+/*
+ * Detach all tasks we were using ptrace on. Called with tasklist held
+ * for writing.
+ */
+void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
+{
+	struct task_struct *p, *n;
+
+	list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
+		if (unlikely(p->ptrace & PT_EXITKILL))
+			send_sig_info(SIGKILL, SEND_SIG_PRIV, p);
+
+		if (__ptrace_detach(tracer, p))
+			list_add(&p->ptrace_entry, dead);
+	}
+}
+
+int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
+{
+	int copied = 0;
+
+	while (len > 0) {
+		char buf[128];
+		int this_len, retval;
+
+		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
+		retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
+
+		if (!retval) {
+			if (copied)
+				break;
+			return -EIO;
+		}
+		if (copy_to_user(dst, buf, retval))
+			return -EFAULT;
+		copied += retval;
+		src += retval;
+		dst += retval;
+		len -= retval;
+	}
+	return copied;
+}
+
+int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
+{
+	int copied = 0;
+
+	while (len > 0) {
+		char buf[128];
+		int this_len, retval;
+
+		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
+		if (copy_from_user(buf, src, this_len))
+			return -EFAULT;
+		retval = ptrace_access_vm(tsk, dst, buf, this_len,
+				FOLL_FORCE | FOLL_WRITE);
+		if (!retval) {
+			if (copied)
+				break;
+			return -EIO;
+		}
+		copied += retval;
+		src += retval;
+		dst += retval;
+		len -= retval;
+	}
+	return copied;
+}
+
+static int ptrace_setoptions(struct task_struct *child, unsigned long data)
+{
+	unsigned flags;
+	int ret;
+
+	ret = check_ptrace_options(data);
+	if (ret)
+		return ret;
+
+	/* Avoid intermediate state when all opts are cleared */
+	flags = child->ptrace;
+	flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
+	flags |= (data << PT_OPT_FLAG_SHIFT);
+	child->ptrace = flags;
+
+	return 0;
+}
+
+static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info)
+{
+	unsigned long flags;
+	int error = -ESRCH;
+
+	if (lock_task_sighand(child, &flags)) {
+		error = -EINVAL;
+		if (likely(child->last_siginfo != NULL)) {
+			copy_siginfo(info, child->last_siginfo);
+			error = 0;
+		}
+		unlock_task_sighand(child, &flags);
+	}
+	return error;
+}
+
+static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
+{
+	unsigned long flags;
+	int error = -ESRCH;
+
+	if (lock_task_sighand(child, &flags)) {
+		error = -EINVAL;
+		if (likely(child->last_siginfo != NULL)) {
+			copy_siginfo(child->last_siginfo, info);
+			error = 0;
+		}
+		unlock_task_sighand(child, &flags);
+	}
+	return error;
+}
+
+static int ptrace_peek_siginfo(struct task_struct *child,
+				unsigned long addr,
+				unsigned long data)
+{
+	struct ptrace_peeksiginfo_args arg;
+	struct sigpending *pending;
+	struct sigqueue *q;
+	int ret, i;
+
+	ret = copy_from_user(&arg, (void __user *) addr,
+				sizeof(struct ptrace_peeksiginfo_args));
+	if (ret)
+		return -EFAULT;
+
+	if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
+		return -EINVAL; /* unknown flags */
+
+	if (arg.nr < 0)
+		return -EINVAL;
+
+	/* Ensure arg.off fits in an unsigned long */
+	if (arg.off > ULONG_MAX)
+		return 0;
+
+	if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
+		pending = &child->signal->shared_pending;
+	else
+		pending = &child->pending;
+
+	for (i = 0; i < arg.nr; ) {
+		kernel_siginfo_t info;
+		unsigned long off = arg.off + i;
+		bool found = false;
+
+		spin_lock_irq(&child->sighand->siglock);
+		list_for_each_entry(q, &pending->list, list) {
+			if (!off--) {
+				found = true;
+				copy_siginfo(&info, &q->info);
+				break;
+			}
+		}
+		spin_unlock_irq(&child->sighand->siglock);
+
+		if (!found) /* beyond the end of the list */
+			break;
+
+#ifdef CONFIG_COMPAT
+		if (unlikely(in_compat_syscall())) {
+			compat_siginfo_t __user *uinfo = compat_ptr(data);
+
+			if (copy_siginfo_to_user32(uinfo, &info)) {
+				ret = -EFAULT;
+				break;
+			}
+
+		} else
+#endif
+		{
+			siginfo_t __user *uinfo = (siginfo_t __user *) data;
+
+			if (copy_siginfo_to_user(uinfo, &info)) {
+				ret = -EFAULT;
+				break;
+			}
+		}
+
+		data += sizeof(siginfo_t);
+		i++;
+
+		if (signal_pending(current))
+			break;
+
+		cond_resched();
+	}
+
+	if (i > 0)
+		return i;
+
+	return ret;
+}
+
+#ifdef CONFIG_RSEQ
+static long ptrace_get_rseq_configuration(struct task_struct *task,
+					  unsigned long size, void __user *data)
+{
+	struct ptrace_rseq_configuration conf = {
+		.rseq_abi_pointer = (u64)(uintptr_t)task->rseq,
+		.rseq_abi_size = sizeof(*task->rseq),
+		.signature = task->rseq_sig,
+		.flags = 0,
+	};
+
+	size = min_t(unsigned long, size, sizeof(conf));
+	if (copy_to_user(data, &conf, size))
+		return -EFAULT;
+	return sizeof(conf);
+}
+#endif
+
+#define is_singlestep(request)		((request) == PTRACE_SINGLESTEP)
+
+#ifdef PTRACE_SINGLEBLOCK
+#define is_singleblock(request)		((request) == PTRACE_SINGLEBLOCK)
+#else
+#define is_singleblock(request)		0
+#endif
+
+#ifdef PTRACE_SYSEMU
+#define is_sysemu_singlestep(request)	((request) == PTRACE_SYSEMU_SINGLESTEP)
+#else
+#define is_sysemu_singlestep(request)	0
+#endif
+
+static int ptrace_resume(struct task_struct *child, long request,
+			 unsigned long data)
+{
+	if (!valid_signal(data))
+		return -EIO;
+
+	if (request == PTRACE_SYSCALL)
+		set_task_syscall_work(child, SYSCALL_TRACE);
+	else
+		clear_task_syscall_work(child, SYSCALL_TRACE);
+
+#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
+	if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
+		set_task_syscall_work(child, SYSCALL_EMU);
+	else
+		clear_task_syscall_work(child, SYSCALL_EMU);
+#endif
+
+	if (is_singleblock(request)) {
+		if (unlikely(!arch_has_block_step()))
+			return -EIO;
+		user_enable_block_step(child);
+	} else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
+		if (unlikely(!arch_has_single_step()))
+			return -EIO;
+		user_enable_single_step(child);
+	} else {
+		user_disable_single_step(child);
+	}
+
+	/*
+	 * Change ->exit_code and ->state under siglock to avoid the race
+	 * with wait_task_stopped() in between; a non-zero ->exit_code will
+	 * wrongly look like another report from tracee.
+	 *
+	 * Note that we need siglock even if ->exit_code == data and/or this
+	 * status was not reported yet, the new status must not be cleared by
+	 * wait_task_stopped() after resume.
+	 */
+	spin_lock_irq(&child->sighand->siglock);
+	child->exit_code = data;
+	child->jobctl &= ~JOBCTL_TRACED;
+	wake_up_state(child, __TASK_TRACED);
+	spin_unlock_irq(&child->sighand->siglock);
+
+	return 0;
+}
+
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+
+static const struct user_regset *
+find_regset(const struct user_regset_view *view, unsigned int type)
+{
+	const struct user_regset *regset;
+	int n;
+
+	for (n = 0; n < view->n; ++n) {
+		regset = view->regsets + n;
+		if (regset->core_note_type == type)
+			return regset;
+	}
+
+	return NULL;
+}
+
+static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
+			 struct iovec *kiov)
+{
+	const struct user_regset_view *view = task_user_regset_view(task);
+	const struct user_regset *regset = find_regset(view, type);
+	int regset_no;
+
+	if (!regset || (kiov->iov_len % regset->size) != 0)
+		return -EINVAL;
+
+	regset_no = regset - view->regsets;
+	kiov->iov_len = min(kiov->iov_len,
+			    (__kernel_size_t) (regset->n * regset->size));
+
+	if (req == PTRACE_GETREGSET)
+		return copy_regset_to_user(task, view, regset_no, 0,
+					   kiov->iov_len, kiov->iov_base);
+	else
+		return copy_regset_from_user(task, view, regset_no, 0,
+					     kiov->iov_len, kiov->iov_base);
+}
+
+/*
+ * This is declared in linux/regset.h and defined in machine-dependent
+ * code.  We put the export here, near the primary machine-neutral use,
+ * to ensure no machine forgets it.
+ */
+EXPORT_SYMBOL_GPL(task_user_regset_view);
+
+static unsigned long
+ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
+			      struct ptrace_syscall_info *info)
+{
+	unsigned long args[ARRAY_SIZE(info->entry.args)];
+	int i;
+
+	info->op = PTRACE_SYSCALL_INFO_ENTRY;
+	info->entry.nr = syscall_get_nr(child, regs);
+	syscall_get_arguments(child, regs, args);
+	for (i = 0; i < ARRAY_SIZE(args); i++)
+		info->entry.args[i] = args[i];
+
+	/* args is the last field in struct ptrace_syscall_info.entry */
+	return offsetofend(struct ptrace_syscall_info, entry.args);
+}
+
+static unsigned long
+ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
+				struct ptrace_syscall_info *info)
+{
+	/*
+	 * As struct ptrace_syscall_info.entry is currently a subset
+	 * of struct ptrace_syscall_info.seccomp, it makes sense to
+	 * initialize that subset using ptrace_get_syscall_info_entry().
+	 * This can be reconsidered in the future if these structures
+	 * diverge significantly enough.
+	 */
+	ptrace_get_syscall_info_entry(child, regs, info);
+	info->op = PTRACE_SYSCALL_INFO_SECCOMP;
+	info->seccomp.ret_data = child->ptrace_message;
+
+	/* ret_data is the last field in struct ptrace_syscall_info.seccomp */
+	return offsetofend(struct ptrace_syscall_info, seccomp.ret_data);
+}
+
+static unsigned long
+ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
+			     struct ptrace_syscall_info *info)
+{
+	info->op = PTRACE_SYSCALL_INFO_EXIT;
+	info->exit.rval = syscall_get_error(child, regs);
+	info->exit.is_error = !!info->exit.rval;
+	if (!info->exit.is_error)
+		info->exit.rval = syscall_get_return_value(child, regs);
+
+	/* is_error is the last field in struct ptrace_syscall_info.exit */
+	return offsetofend(struct ptrace_syscall_info, exit.is_error);
+}
+
+static int
+ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
+			void __user *datavp)
+{
+	struct pt_regs *regs = task_pt_regs(child);
+	struct ptrace_syscall_info info = {
+		.op = PTRACE_SYSCALL_INFO_NONE,
+		.arch = syscall_get_arch(child),
+		.instruction_pointer = instruction_pointer(regs),
+		.stack_pointer = user_stack_pointer(regs),
+	};
+	unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
+	unsigned long write_size;
+
+	/*
+	 * This does not need lock_task_sighand() to access
+	 * child->last_siginfo because ptrace_freeze_traced()
+	 * called earlier by ptrace_check_attach() ensures that
+	 * the tracee cannot go away and clear its last_siginfo.
+	 */
+	switch (child->last_siginfo ? child->last_siginfo->si_code : 0) {
+	case SIGTRAP | 0x80:
+		switch (child->ptrace_message) {
+		case PTRACE_EVENTMSG_SYSCALL_ENTRY:
+			actual_size = ptrace_get_syscall_info_entry(child, regs,
+								    &info);
+			break;
+		case PTRACE_EVENTMSG_SYSCALL_EXIT:
+			actual_size = ptrace_get_syscall_info_exit(child, regs,
+								   &info);
+			break;
+		}
+		break;
+	case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
+		actual_size = ptrace_get_syscall_info_seccomp(child, regs,
+							      &info);
+		break;
+	}
+
+	write_size = min(actual_size, user_size);
+	return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size;
+}
+#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
+
+int ptrace_request(struct task_struct *child, long request,
+		   unsigned long addr, unsigned long data)
+{
+	bool seized = child->ptrace & PT_SEIZED;
+	int ret = -EIO;
+	kernel_siginfo_t siginfo, *si;
+	void __user *datavp = (void __user *) data;
+	unsigned long __user *datalp = datavp;
+	unsigned long flags;
+
+	switch (request) {
+	case PTRACE_PEEKTEXT:
+	case PTRACE_PEEKDATA:
+		return generic_ptrace_peekdata(child, addr, data);
+	case PTRACE_POKETEXT:
+	case PTRACE_POKEDATA:
+		return generic_ptrace_pokedata(child, addr, data);
+
+#ifdef PTRACE_OLDSETOPTIONS
+	case PTRACE_OLDSETOPTIONS:
+#endif
+	case PTRACE_SETOPTIONS:
+		ret = ptrace_setoptions(child, data);
+		break;
+	case PTRACE_GETEVENTMSG:
+		ret = put_user(child->ptrace_message, datalp);
+		break;
+
+	case PTRACE_PEEKSIGINFO:
+		ret = ptrace_peek_siginfo(child, addr, data);
+		break;
+
+	case PTRACE_GETSIGINFO:
+		ret = ptrace_getsiginfo(child, &siginfo);
+		if (!ret)
+			ret = copy_siginfo_to_user(datavp, &siginfo);
+		break;
+
+	case PTRACE_SETSIGINFO:
+		ret = copy_siginfo_from_user(&siginfo, datavp);
+		if (!ret)
+			ret = ptrace_setsiginfo(child, &siginfo);
+		break;
+
+	case PTRACE_GETSIGMASK: {
+		sigset_t *mask;
+
+		if (addr != sizeof(sigset_t)) {
+			ret = -EINVAL;
+			break;
+		}
+
+		if (test_tsk_restore_sigmask(child))
+			mask = &child->saved_sigmask;
+		else
+			mask = &child->blocked;
+
+		if (copy_to_user(datavp, mask, sizeof(sigset_t)))
+			ret = -EFAULT;
+		else
+			ret = 0;
+
+		break;
+	}
+
+	case PTRACE_SETSIGMASK: {
+		sigset_t new_set;
+
+		if (addr != sizeof(sigset_t)) {
+			ret = -EINVAL;
+			break;
+		}
+
+		if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
+			ret = -EFAULT;
+			break;
+		}
+
+		sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
+
+		/*
+		 * Every thread does recalc_sigpending() after resume, so
+		 * retarget_shared_pending() and recalc_sigpending() are not
+		 * called here.
+		 */
+		spin_lock_irq(&child->sighand->siglock);
+		child->blocked = new_set;
+		spin_unlock_irq(&child->sighand->siglock);
+
+		clear_tsk_restore_sigmask(child);
+
+		ret = 0;
+		break;
+	}
+
+	case PTRACE_INTERRUPT:
+		/*
+		 * Stop tracee without any side-effect on signal or job
+		 * control.  At least one trap is guaranteed to happen
+		 * after this request.  If @child is already trapped, the
+		 * current trap is not disturbed and another trap will
+		 * happen after the current trap is ended with PTRACE_CONT.
+		 *
+		 * The actual trap might not be PTRACE_EVENT_STOP trap but
+		 * the pending condition is cleared regardless.
+		 */
+		if (unlikely(!seized || !lock_task_sighand(child, &flags)))
+			break;
+
+		/*
+		 * INTERRUPT doesn't disturb existing trap sans one
+		 * exception.  If ptracer issued LISTEN for the current
+		 * STOP, this INTERRUPT should clear LISTEN and re-trap
+		 * tracee into STOP.
+		 */
+		if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
+			ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
+
+		unlock_task_sighand(child, &flags);
+		ret = 0;
+		break;
+
+	case PTRACE_LISTEN:
+		/*
+		 * Listen for events.  Tracee must be in STOP.  It's not
+		 * resumed per-se but is not considered to be in TRACED by
+		 * wait(2) or ptrace(2).  If an async event (e.g. group
+		 * stop state change) happens, tracee will enter STOP trap
+		 * again.  Alternatively, ptracer can issue INTERRUPT to
+		 * finish listening and re-trap tracee into STOP.
+		 */
+		if (unlikely(!seized || !lock_task_sighand(child, &flags)))
+			break;
+
+		si = child->last_siginfo;
+		if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
+			child->jobctl |= JOBCTL_LISTENING;
+			/*
+			 * If NOTIFY is set, it means event happened between
+			 * start of this trap and now.  Trigger re-trap.
+			 */
+			if (child->jobctl & JOBCTL_TRAP_NOTIFY)
+				ptrace_signal_wake_up(child, true);
+			ret = 0;
+		}
+		unlock_task_sighand(child, &flags);
+		break;
+
+	case PTRACE_DETACH:	 /* detach a process that was attached. */
+		ret = ptrace_detach(child, data);
+		break;
+
+#ifdef CONFIG_BINFMT_ELF_FDPIC
+	case PTRACE_GETFDPIC: {
+		struct mm_struct *mm = get_task_mm(child);
+		unsigned long tmp = 0;
+
+		ret = -ESRCH;
+		if (!mm)
+			break;
+
+		switch (addr) {
+		case PTRACE_GETFDPIC_EXEC:
+			tmp = mm->context.exec_fdpic_loadmap;
+			break;
+		case PTRACE_GETFDPIC_INTERP:
+			tmp = mm->context.interp_fdpic_loadmap;
+			break;
+		default:
+			break;
+		}
+		mmput(mm);
+
+		ret = put_user(tmp, datalp);
+		break;
+	}
+#endif
+
+	case PTRACE_SINGLESTEP:
+#ifdef PTRACE_SINGLEBLOCK
+	case PTRACE_SINGLEBLOCK:
+#endif
+#ifdef PTRACE_SYSEMU
+	case PTRACE_SYSEMU:
+	case PTRACE_SYSEMU_SINGLESTEP:
+#endif
+	case PTRACE_SYSCALL:
+	case PTRACE_CONT:
+		return ptrace_resume(child, request, data);
+
+	case PTRACE_KILL:
+		send_sig_info(SIGKILL, SEND_SIG_NOINFO, child);
+		return 0;
+
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+	case PTRACE_GETREGSET:
+	case PTRACE_SETREGSET: {
+		struct iovec kiov;
+		struct iovec __user *uiov = datavp;
+
+		if (!access_ok(uiov, sizeof(*uiov)))
+			return -EFAULT;
+
+		if (__get_user(kiov.iov_base, &uiov->iov_base) ||
+		    __get_user(kiov.iov_len, &uiov->iov_len))
+			return -EFAULT;
+
+		ret = ptrace_regset(child, request, addr, &kiov);
+		if (!ret)
+			ret = __put_user(kiov.iov_len, &uiov->iov_len);
+		break;
+	}
+
+	case PTRACE_GET_SYSCALL_INFO:
+		ret = ptrace_get_syscall_info(child, addr, datavp);
+		break;
+#endif
+
+	case PTRACE_SECCOMP_GET_FILTER:
+		ret = seccomp_get_filter(child, addr, datavp);
+		break;
+
+	case PTRACE_SECCOMP_GET_METADATA:
+		ret = seccomp_get_metadata(child, addr, datavp);
+		break;
+
+#ifdef CONFIG_RSEQ
+	case PTRACE_GET_RSEQ_CONFIGURATION:
+		ret = ptrace_get_rseq_configuration(child, addr, datavp);
+		break;
+#endif
+
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
+		unsigned long, data)
+{
+	struct task_struct *child;
+	long ret;
+
+	if (request == PTRACE_TRACEME) {
+		ret = ptrace_traceme();
+		goto out;
+	}
+
+	child = find_get_task_by_vpid(pid);
+	if (!child) {
+		ret = -ESRCH;
+		goto out;
+	}
+
+	if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
+		ret = ptrace_attach(child, request, addr, data);
+		goto out_put_task_struct;
+	}
+
+	ret = ptrace_check_attach(child, request == PTRACE_KILL ||
+				  request == PTRACE_INTERRUPT);
+	if (ret < 0)
+		goto out_put_task_struct;
+
+	ret = arch_ptrace(child, request, addr, data);
+	if (ret || request != PTRACE_DETACH)
+		ptrace_unfreeze_traced(child);
+
+ out_put_task_struct:
+	put_task_struct(child);
+ out:
+	return ret;
+}
+
+int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
+			    unsigned long data)
+{
+	unsigned long tmp;
+	int copied;
+
+	copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
+	if (copied != sizeof(tmp))
+		return -EIO;
+	return put_user(tmp, (unsigned long __user *)data);
+}
+
+int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
+			    unsigned long data)
+{
+	int copied;
+
+	copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
+			FOLL_FORCE | FOLL_WRITE);
+	return (copied == sizeof(data)) ? 0 : -EIO;
+}
+
+#if defined CONFIG_COMPAT
+
+int compat_ptrace_request(struct task_struct *child, compat_long_t request,
+			  compat_ulong_t addr, compat_ulong_t data)
+{
+	compat_ulong_t __user *datap = compat_ptr(data);
+	compat_ulong_t word;
+	kernel_siginfo_t siginfo;
+	int ret;
+
+	switch (request) {
+	case PTRACE_PEEKTEXT:
+	case PTRACE_PEEKDATA:
+		ret = ptrace_access_vm(child, addr, &word, sizeof(word),
+				FOLL_FORCE);
+		if (ret != sizeof(word))
+			ret = -EIO;
+		else
+			ret = put_user(word, datap);
+		break;
+
+	case PTRACE_POKETEXT:
+	case PTRACE_POKEDATA:
+		ret = ptrace_access_vm(child, addr, &data, sizeof(data),
+				FOLL_FORCE | FOLL_WRITE);
+		ret = (ret != sizeof(data) ? -EIO : 0);
+		break;
+
+	case PTRACE_GETEVENTMSG:
+		ret = put_user((compat_ulong_t) child->ptrace_message, datap);
+		break;
+
+	case PTRACE_GETSIGINFO:
+		ret = ptrace_getsiginfo(child, &siginfo);
+		if (!ret)
+			ret = copy_siginfo_to_user32(
+				(struct compat_siginfo __user *) datap,
+				&siginfo);
+		break;
+
+	case PTRACE_SETSIGINFO:
+		ret = copy_siginfo_from_user32(
+			&siginfo, (struct compat_siginfo __user *) datap);
+		if (!ret)
+			ret = ptrace_setsiginfo(child, &siginfo);
+		break;
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+	case PTRACE_GETREGSET:
+	case PTRACE_SETREGSET:
+	{
+		struct iovec kiov;
+		struct compat_iovec __user *uiov =
+			(struct compat_iovec __user *) datap;
+		compat_uptr_t ptr;
+		compat_size_t len;
+
+		if (!access_ok(uiov, sizeof(*uiov)))
+			return -EFAULT;
+
+		if (__get_user(ptr, &uiov->iov_base) ||
+		    __get_user(len, &uiov->iov_len))
+			return -EFAULT;
+
+		kiov.iov_base = compat_ptr(ptr);
+		kiov.iov_len = len;
+
+		ret = ptrace_regset(child, request, addr, &kiov);
+		if (!ret)
+			ret = __put_user(kiov.iov_len, &uiov->iov_len);
+		break;
+	}
+#endif
+
+	default:
+		ret = ptrace_request(child, request, addr, data);
+	}
+
+	return ret;
+}
+
+COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
+		       compat_long_t, addr, compat_long_t, data)
+{
+	struct task_struct *child;
+	long ret;
+
+	if (request == PTRACE_TRACEME) {
+		ret = ptrace_traceme();
+		goto out;
+	}
+
+	child = find_get_task_by_vpid(pid);
+	if (!child) {
+		ret = -ESRCH;
+		goto out;
+	}
+
+	if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
+		ret = ptrace_attach(child, request, addr, data);
+		goto out_put_task_struct;
+	}
+
+	ret = ptrace_check_attach(child, request == PTRACE_KILL ||
+				  request == PTRACE_INTERRUPT);
+	if (!ret) {
+		ret = compat_arch_ptrace(child, request, addr, data);
+		if (ret || request != PTRACE_DETACH)
+			ptrace_unfreeze_traced(child);
+	}
+
+ out_put_task_struct:
+	put_task_struct(child);
+ out:
+	return ret;
+}
+#endif	/* CONFIG_COMPAT */
diff --git a/kernel/range.c b/kernel/range.c
new file mode 100644
index 000000000..56435f96d
--- /dev/null
+++ b/kernel/range.c
@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Range add and subtract
+ */
+#include <linux/init.h>
+#include <linux/minmax.h>
+#include <linux/printk.h>
+#include <linux/sort.h>
+#include <linux/string.h>
+#include <linux/range.h>
+
+int add_range(struct range *range, int az, int nr_range, u64 start, u64 end)
+{
+	if (start >= end)
+		return nr_range;
+
+	/* Out of slots: */
+	if (nr_range >= az)
+		return nr_range;
+
+	range[nr_range].start = start;
+	range[nr_range].end = end;
+
+	nr_range++;
+
+	return nr_range;
+}
+
+int add_range_with_merge(struct range *range, int az, int nr_range,
+		     u64 start, u64 end)
+{
+	int i;
+
+	if (start >= end)
+		return nr_range;
+
+	/* get new start/end: */
+	for (i = 0; i < nr_range; i++) {
+		u64 common_start, common_end;
+
+		if (!range[i].end)
+			continue;
+
+		common_start = max(range[i].start, start);
+		common_end = min(range[i].end, end);
+		if (common_start > common_end)
+			continue;
+
+		/* new start/end, will add it back at last */
+		start = min(range[i].start, start);
+		end = max(range[i].end, end);
+
+		memmove(&range[i], &range[i + 1],
+			(nr_range - (i + 1)) * sizeof(range[i]));
+		range[nr_range - 1].start = 0;
+		range[nr_range - 1].end   = 0;
+		nr_range--;
+		i--;
+	}
+
+	/* Need to add it: */
+	return add_range(range, az, nr_range, start, end);
+}
+
+void subtract_range(struct range *range, int az, u64 start, u64 end)
+{
+	int i, j;
+
+	if (start >= end)
+		return;
+
+	for (j = 0; j < az; j++) {
+		if (!range[j].end)
+			continue;
+
+		if (start <= range[j].start && end >= range[j].end) {
+			range[j].start = 0;
+			range[j].end = 0;
+			continue;
+		}
+
+		if (start <= range[j].start && end < range[j].end &&
+		    range[j].start < end) {
+			range[j].start = end;
+			continue;
+		}
+
+
+		if (start > range[j].start && end >= range[j].end &&
+		    range[j].end > start) {
+			range[j].end = start;
+			continue;
+		}
+
+		if (start > range[j].start && end < range[j].end) {
+			/* Find the new spare: */
+			for (i = 0; i < az; i++) {
+				if (range[i].end == 0)
+					break;
+			}
+			if (i < az) {
+				range[i].end = range[j].end;
+				range[i].start = end;
+			} else {
+				pr_err("%s: run out of slot in ranges\n",
+					__func__);
+			}
+			range[j].end = start;
+			continue;
+		}
+	}
+}
+
+static int cmp_range(const void *x1, const void *x2)
+{
+	const struct range *r1 = x1;
+	const struct range *r2 = x2;
+
+	if (r1->start < r2->start)
+		return -1;
+	if (r1->start > r2->start)
+		return 1;
+	return 0;
+}
+
+int clean_sort_range(struct range *range, int az)
+{
+	int i, j, k = az - 1, nr_range = az;
+
+	for (i = 0; i < k; i++) {
+		if (range[i].end)
+			continue;
+		for (j = k; j > i; j--) {
+			if (range[j].end) {
+				k = j;
+				break;
+			}
+		}
+		if (j == i)
+			break;
+		range[i].start = range[k].start;
+		range[i].end   = range[k].end;
+		range[k].start = 0;
+		range[k].end   = 0;
+		k--;
+	}
+	/* count it */
+	for (i = 0; i < az; i++) {
+		if (!range[i].end) {
+			nr_range = i;
+			break;
+		}
+	}
+
+	/* sort them */
+	sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
+
+	return nr_range;
+}
+
+void sort_range(struct range *range, int nr_range)
+{
+	/* sort them */
+	sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
+}
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
new file mode 100644
index 000000000..d471d22a5
--- /dev/null
+++ b/kernel/rcu/Kconfig
@@ -0,0 +1,314 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# RCU-related configuration options
+#
+
+menu "RCU Subsystem"
+
+config TREE_RCU
+	bool
+	default y if SMP
+	# Dynticks-idle tracking
+	select CONTEXT_TRACKING_IDLE
+	help
+	  This option selects the RCU implementation that is
+	  designed for very large SMP system with hundreds or
+	  thousands of CPUs.  It also scales down nicely to
+	  smaller systems.
+
+config PREEMPT_RCU
+	bool
+	default y if PREEMPTION
+	select TREE_RCU
+	help
+	  This option selects the RCU implementation that is
+	  designed for very large SMP systems with hundreds or
+	  thousands of CPUs, but for which real-time response
+	  is also required.  It also scales down nicely to
+	  smaller systems.
+
+	  Select this option if you are unsure.
+
+config TINY_RCU
+	bool
+	default y if !PREEMPTION && !SMP
+	help
+	  This option selects the RCU implementation that is
+	  designed for UP systems from which real-time response
+	  is not required.  This option greatly reduces the
+	  memory footprint of RCU.
+
+config RCU_EXPERT
+	bool "Make expert-level adjustments to RCU configuration"
+	default n
+	help
+	  This option needs to be enabled if you wish to make
+	  expert-level adjustments to RCU configuration.  By default,
+	  no such adjustments can be made, which has the often-beneficial
+	  side-effect of preventing "make oldconfig" from asking you all
+	  sorts of detailed questions about how you would like numerous
+	  obscure RCU options to be set up.
+
+	  Say Y if you need to make expert-level adjustments to RCU.
+
+	  Say N if you are unsure.
+
+config SRCU
+	bool
+	help
+	  This option selects the sleepable version of RCU. This version
+	  permits arbitrary sleeping or blocking within RCU read-side critical
+	  sections.
+
+config TINY_SRCU
+	bool
+	default y if SRCU && TINY_RCU
+	help
+	  This option selects the single-CPU non-preemptible version of SRCU.
+
+config TREE_SRCU
+	bool
+	default y if SRCU && !TINY_RCU
+	help
+	  This option selects the full-fledged version of SRCU.
+
+config TASKS_RCU_GENERIC
+	def_bool TASKS_RCU || TASKS_RUDE_RCU || TASKS_TRACE_RCU
+	select SRCU
+	help
+	  This option enables generic infrastructure code supporting
+	  task-based RCU implementations.  Not for manual selection.
+
+config FORCE_TASKS_RCU
+	bool "Force selection of TASKS_RCU"
+	depends on RCU_EXPERT
+	select TASKS_RCU
+	default n
+	help
+	  This option force-enables a task-based RCU implementation
+	  that uses only voluntary context switch (not preemption!),
+	  idle, and user-mode execution as quiescent states.  Not for
+	  manual selection in most cases.
+
+config TASKS_RCU
+	bool
+	default n
+	select IRQ_WORK
+
+config FORCE_TASKS_RUDE_RCU
+	bool "Force selection of Tasks Rude RCU"
+	depends on RCU_EXPERT
+	select TASKS_RUDE_RCU
+	default n
+	help
+	  This option force-enables a task-based RCU implementation
+	  that uses only context switch (including preemption) and
+	  user-mode execution as quiescent states.  It forces IPIs and
+	  context switches on all online CPUs, including idle ones,
+	  so use with caution.	Not for manual selection in most cases.
+
+config TASKS_RUDE_RCU
+	bool
+	default n
+	select IRQ_WORK
+
+config FORCE_TASKS_TRACE_RCU
+	bool "Force selection of Tasks Trace RCU"
+	depends on RCU_EXPERT
+	select TASKS_TRACE_RCU
+	default n
+	help
+	  This option enables a task-based RCU implementation that uses
+	  explicit rcu_read_lock_trace() read-side markers, and allows
+	  these readers to appear in the idle loop as well as on the
+	  CPU hotplug code paths.  It can force IPIs on online CPUs,
+	  including idle ones, so use with caution.  Not for manual
+	  selection in most cases.
+
+config TASKS_TRACE_RCU
+	bool
+	default n
+	select IRQ_WORK
+
+config RCU_STALL_COMMON
+	def_bool TREE_RCU
+	help
+	  This option enables RCU CPU stall code that is common between
+	  the TINY and TREE variants of RCU.  The purpose is to allow
+	  the tiny variants to disable RCU CPU stall warnings, while
+	  making these warnings mandatory for the tree variants.
+
+config RCU_NEED_SEGCBLIST
+	def_bool ( TREE_RCU || TREE_SRCU || TASKS_RCU_GENERIC )
+
+config RCU_FANOUT
+	int "Tree-based hierarchical RCU fanout value"
+	range 2 64 if 64BIT
+	range 2 32 if !64BIT
+	depends on TREE_RCU && RCU_EXPERT
+	default 64 if 64BIT
+	default 32 if !64BIT
+	help
+	  This option controls the fanout of hierarchical implementations
+	  of RCU, allowing RCU to work efficiently on machines with
+	  large numbers of CPUs.  This value must be at least the fourth
+	  root of NR_CPUS, which allows NR_CPUS to be insanely large.
+	  The default value of RCU_FANOUT should be used for production
+	  systems, but if you are stress-testing the RCU implementation
+	  itself, small RCU_FANOUT values allow you to test large-system
+	  code paths on small(er) systems.
+
+	  Select a specific number if testing RCU itself.
+	  Take the default if unsure.
+
+config RCU_FANOUT_LEAF
+	int "Tree-based hierarchical RCU leaf-level fanout value"
+	range 2 64 if 64BIT && !RCU_STRICT_GRACE_PERIOD
+	range 2 32 if !64BIT && !RCU_STRICT_GRACE_PERIOD
+	range 2 3 if RCU_STRICT_GRACE_PERIOD
+	depends on TREE_RCU && RCU_EXPERT
+	default 16 if !RCU_STRICT_GRACE_PERIOD
+	default 2 if RCU_STRICT_GRACE_PERIOD
+	help
+	  This option controls the leaf-level fanout of hierarchical
+	  implementations of RCU, and allows trading off cache misses
+	  against lock contention.  Systems that synchronize their
+	  scheduling-clock interrupts for energy-efficiency reasons will
+	  want the default because the smaller leaf-level fanout keeps
+	  lock contention levels acceptably low.  Very large systems
+	  (hundreds or thousands of CPUs) will instead want to set this
+	  value to the maximum value possible in order to reduce the
+	  number of cache misses incurred during RCU's grace-period
+	  initialization.  These systems tend to run CPU-bound, and thus
+	  are not helped by synchronized interrupts, and thus tend to
+	  skew them, which reduces lock contention enough that large
+	  leaf-level fanouts work well.  That said, setting leaf-level
+	  fanout to a large number will likely cause problematic
+	  lock contention on the leaf-level rcu_node structures unless
+	  you boot with the skew_tick kernel parameter.
+
+	  Select a specific number if testing RCU itself.
+
+	  Select the maximum permissible value for large systems, but
+	  please understand that you may also need to set the skew_tick
+	  kernel boot parameter to avoid contention on the rcu_node
+	  structure's locks.
+
+	  Take the default if unsure.
+
+config RCU_BOOST
+	bool "Enable RCU priority boosting"
+	depends on (RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT) || PREEMPT_RT
+	default y if PREEMPT_RT
+	help
+	  This option boosts the priority of preempted RCU readers that
+	  block the current preemptible RCU grace period for too long.
+	  This option also prevents heavy loads from blocking RCU
+	  callback invocation.
+
+	  Say Y here if you are working with real-time apps or heavy loads
+	  Say N here if you are unsure.
+
+config RCU_BOOST_DELAY
+	int "Milliseconds to delay boosting after RCU grace-period start"
+	range 0 3000
+	depends on RCU_BOOST
+	default 500
+	help
+	  This option specifies the time to wait after the beginning of
+	  a given grace period before priority-boosting preempted RCU
+	  readers blocking that grace period.  Note that any RCU reader
+	  blocking an expedited RCU grace period is boosted immediately.
+
+	  Accept the default if unsure.
+
+config RCU_EXP_KTHREAD
+	bool "Perform RCU expedited work in a real-time kthread"
+	depends on RCU_BOOST && RCU_EXPERT
+	default !PREEMPT_RT && NR_CPUS <= 32
+	help
+	  Use this option to further reduce the latencies of expedited
+	  grace periods at the expense of being more disruptive.
+
+	  This option is disabled by default on PREEMPT_RT=y kernels which
+	  disable expedited grace periods after boot by unconditionally
+	  setting rcupdate.rcu_normal_after_boot=1.
+
+	  Accept the default if unsure.
+
+config RCU_NOCB_CPU
+	bool "Offload RCU callback processing from boot-selected CPUs"
+	depends on TREE_RCU
+	depends on RCU_EXPERT || NO_HZ_FULL
+	default n
+	help
+	  Use this option to reduce OS jitter for aggressive HPC or
+	  real-time workloads.	It can also be used to offload RCU
+	  callback invocation to energy-efficient CPUs in battery-powered
+	  asymmetric multiprocessors.  The price of this reduced jitter
+	  is that the overhead of call_rcu() increases and that some
+	  workloads will incur significant increases in context-switch
+	  rates.
+
+	  This option offloads callback invocation from the set of CPUs
+	  specified at boot time by the rcu_nocbs parameter.  For each
+	  such CPU, a kthread ("rcuox/N") will be created to invoke
+	  callbacks, where the "N" is the CPU being offloaded, and where
+	  the "x" is "p" for RCU-preempt (PREEMPTION kernels) and "s" for
+	  RCU-sched (!PREEMPTION kernels).  Nothing prevents this kthread
+	  from running on the specified CPUs, but (1) the kthreads may be
+	  preempted between each callback, and (2) affinity or cgroups can
+	  be used to force the kthreads to run on whatever set of CPUs is
+	  desired.
+
+	  Say Y here if you need reduced OS jitter, despite added overhead.
+	  Say N here if you are unsure.
+
+config RCU_NOCB_CPU_DEFAULT_ALL
+	bool "Offload RCU callback processing from all CPUs by default"
+	depends on RCU_NOCB_CPU
+	default n
+	help
+	  Use this option to offload callback processing from all CPUs
+	  by default, in the absence of the rcu_nocbs or nohz_full boot
+	  parameter. This also avoids the need to use any boot parameters
+	  to achieve the effect of offloading all CPUs on boot.
+
+	  Say Y here if you want offload all CPUs by default on boot.
+	  Say N here if you are unsure.
+
+config RCU_NOCB_CPU_CB_BOOST
+	bool "Offload RCU callback from real-time kthread"
+	depends on RCU_NOCB_CPU && RCU_BOOST
+	default y if PREEMPT_RT
+	help
+	  Use this option to invoke offloaded callbacks as SCHED_FIFO
+	  to avoid starvation by heavy SCHED_OTHER background load.
+	  Of course, running as SCHED_FIFO during callback floods will
+	  cause the rcuo[ps] kthreads to monopolize the CPU for hundreds
+	  of milliseconds or more.  Therefore, when enabling this option,
+	  it is your responsibility to ensure that latency-sensitive
+	  tasks either run with higher priority or run on some other CPU.
+
+	  Say Y here if you want to set RT priority for offloading kthreads.
+	  Say N here if you are building a !PREEMPT_RT kernel and are unsure.
+
+config TASKS_TRACE_RCU_READ_MB
+	bool "Tasks Trace RCU readers use memory barriers in user and idle"
+	depends on RCU_EXPERT && TASKS_TRACE_RCU
+	default PREEMPT_RT || NR_CPUS < 8
+	help
+	  Use this option to further reduce the number of IPIs sent
+	  to CPUs executing in userspace or idle during tasks trace
+	  RCU grace periods.  Given that a reasonable setting of
+	  the rcupdate.rcu_task_ipi_delay kernel boot parameter
+	  eliminates such IPIs for many workloads, proper setting
+	  of this Kconfig option is important mostly for aggressive
+	  real-time installations and for battery-powered devices,
+	  hence the default chosen above.
+
+	  Say Y here if you hate IPIs.
+	  Say N here if you hate read-side memory barriers.
+	  Take the default if you are unsure.
+
+endmenu # "RCU Subsystem"
diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
new file mode 100644
index 000000000..1b0c41d49
--- /dev/null
+++ b/kernel/rcu/Kconfig.debug
@@ -0,0 +1,136 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# RCU-related debugging configuration options
+#
+
+menu "RCU Debugging"
+
+config PROVE_RCU
+	def_bool PROVE_LOCKING
+
+config PROVE_RCU_LIST
+	bool "RCU list lockdep debugging"
+	depends on PROVE_RCU && RCU_EXPERT
+	default n
+	help
+	  Enable RCU lockdep checking for list usages. By default it is
+	  turned off since there are several list RCU users that still
+	  need to be converted to pass a lockdep expression. To prevent
+	  false-positive splats, we keep it default disabled but once all
+	  users are converted, we can remove this config option.
+
+config TORTURE_TEST
+	tristate
+	default n
+
+config RCU_SCALE_TEST
+	tristate "performance tests for RCU"
+	depends on DEBUG_KERNEL
+	select TORTURE_TEST
+	select SRCU
+	default n
+	help
+	  This option provides a kernel module that runs performance
+	  tests on the RCU infrastructure.  The kernel module may be built
+	  after the fact on the running kernel to be tested, if desired.
+
+	  Say Y here if you want RCU performance tests to be built into
+	  the kernel.
+	  Say M if you want the RCU performance tests to build as a module.
+	  Say N if you are unsure.
+
+config RCU_TORTURE_TEST
+	tristate "torture tests for RCU"
+	depends on DEBUG_KERNEL
+	select TORTURE_TEST
+	select SRCU
+	default n
+	help
+	  This option provides a kernel module that runs torture tests
+	  on the RCU infrastructure.  The kernel module may be built
+	  after the fact on the running kernel to be tested, if desired.
+
+	  Say Y here if you want RCU torture tests to be built into
+	  the kernel.
+	  Say M if you want the RCU torture tests to build as a module.
+	  Say N if you are unsure.
+
+config RCU_REF_SCALE_TEST
+	tristate "Scalability tests for read-side synchronization (RCU and others)"
+	depends on DEBUG_KERNEL
+	select TORTURE_TEST
+	select SRCU
+	default n
+	help
+	  This option provides a kernel module that runs performance tests
+	  useful comparing RCU with various read-side synchronization mechanisms.
+	  The kernel module may be built after the fact on the running kernel to be
+	  tested, if desired.
+
+	  Say Y here if you want these performance tests built into the kernel.
+	  Say M if you want to build it as a module instead.
+	  Say N if you are unsure.
+
+config RCU_CPU_STALL_TIMEOUT
+	int "RCU CPU stall timeout in seconds"
+	depends on RCU_STALL_COMMON
+	range 3 300
+	default 21
+	help
+	  If a given RCU grace period extends more than the specified
+	  number of seconds, a CPU stall warning is printed.  If the
+	  RCU grace period persists, additional CPU stall warnings are
+	  printed at more widely spaced intervals.
+
+config RCU_EXP_CPU_STALL_TIMEOUT
+	int "Expedited RCU CPU stall timeout in milliseconds"
+	depends on RCU_STALL_COMMON
+	range 0 21000
+	default 0
+	help
+	  If a given expedited RCU grace period extends more than the
+	  specified number of milliseconds, a CPU stall warning is printed.
+	  If the RCU grace period persists, additional CPU stall warnings
+	  are printed at more widely spaced intervals.  A value of zero
+	  says to use the RCU_CPU_STALL_TIMEOUT value converted from
+	  seconds to milliseconds.
+
+config RCU_TRACE
+	bool "Enable tracing for RCU"
+	depends on DEBUG_KERNEL
+	default y if TREE_RCU
+	select TRACE_CLOCK
+	help
+	  This option enables additional tracepoints for ftrace-style
+	  event tracing.
+
+	  Say Y here if you want to enable RCU tracing
+	  Say N if you are unsure.
+
+config RCU_EQS_DEBUG
+	bool "Provide debugging asserts for adding NO_HZ support to an arch"
+	depends on DEBUG_KERNEL
+	help
+	  This option provides consistency checks in RCU's handling of
+	  NO_HZ.  These checks have proven quite helpful in detecting
+	  bugs in arch-specific NO_HZ code.
+
+	  Say N here if you need ultimate kernel/user switch latencies
+	  Say Y if you are unsure
+
+config RCU_STRICT_GRACE_PERIOD
+	bool "Provide debug RCU implementation with short grace periods"
+	depends on DEBUG_KERNEL && RCU_EXPERT && NR_CPUS <= 4 && !TINY_RCU
+	default n
+	select PREEMPT_COUNT if PREEMPT=n
+	help
+	  Select this option to build an RCU variant that is strict about
+	  grace periods, making them as short as it can.  This limits
+	  scalability, destroys real-time response, degrades battery
+	  lifetime and kills performance.  Don't try this on large
+	  machines, as in systems with more than about 10 or 20 CPUs.
+	  But in conjunction with tools like KASAN, it can be helpful
+	  when looking for certain types of RCU usage bugs, for example,
+	  too-short RCU read-side critical sections.
+
+endmenu # "RCU Debugging"
diff --git a/kernel/rcu/Makefile b/kernel/rcu/Makefile
new file mode 100644
index 000000000..0cfb009a9
--- /dev/null
+++ b/kernel/rcu/Makefile
@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0
+# Any varying coverage in these files is non-deterministic
+# and is generally not a function of system call inputs.
+KCOV_INSTRUMENT := n
+
+ifeq ($(CONFIG_KCSAN),y)
+KBUILD_CFLAGS += -g -fno-omit-frame-pointer
+endif
+
+obj-y += update.o sync.o
+obj-$(CONFIG_TREE_SRCU) += srcutree.o
+obj-$(CONFIG_TINY_SRCU) += srcutiny.o
+obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
+obj-$(CONFIG_RCU_SCALE_TEST) += rcuscale.o
+obj-$(CONFIG_RCU_REF_SCALE_TEST) += refscale.o
+obj-$(CONFIG_TREE_RCU) += tree.o
+obj-$(CONFIG_TINY_RCU) += tiny.o
+obj-$(CONFIG_RCU_NEED_SEGCBLIST) += rcu_segcblist.o
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
new file mode 100644
index 000000000..48d8f754b
--- /dev/null
+++ b/kernel/rcu/rcu.h
@@ -0,0 +1,592 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Read-Copy Update definitions shared among RCU implementations.
+ *
+ * Copyright IBM Corporation, 2011
+ *
+ * Author: Paul E. McKenney <paulmck@linux.ibm.com>
+ */
+
+#ifndef __LINUX_RCU_H
+#define __LINUX_RCU_H
+
+#include <trace/events/rcu.h>
+
+/*
+ * Grace-period counter management.
+ */
+
+#define RCU_SEQ_CTR_SHIFT	2
+#define RCU_SEQ_STATE_MASK	((1 << RCU_SEQ_CTR_SHIFT) - 1)
+
+/* Low-order bit definition for polled grace-period APIs. */
+#define RCU_GET_STATE_COMPLETED	0x1
+
+extern int sysctl_sched_rt_runtime;
+
+/*
+ * Return the counter portion of a sequence number previously returned
+ * by rcu_seq_snap() or rcu_seq_current().
+ */
+static inline unsigned long rcu_seq_ctr(unsigned long s)
+{
+	return s >> RCU_SEQ_CTR_SHIFT;
+}
+
+/*
+ * Return the state portion of a sequence number previously returned
+ * by rcu_seq_snap() or rcu_seq_current().
+ */
+static inline int rcu_seq_state(unsigned long s)
+{
+	return s & RCU_SEQ_STATE_MASK;
+}
+
+/*
+ * Set the state portion of the pointed-to sequence number.
+ * The caller is responsible for preventing conflicting updates.
+ */
+static inline void rcu_seq_set_state(unsigned long *sp, int newstate)
+{
+	WARN_ON_ONCE(newstate & ~RCU_SEQ_STATE_MASK);
+	WRITE_ONCE(*sp, (*sp & ~RCU_SEQ_STATE_MASK) + newstate);
+}
+
+/* Adjust sequence number for start of update-side operation. */
+static inline void rcu_seq_start(unsigned long *sp)
+{
+	WRITE_ONCE(*sp, *sp + 1);
+	smp_mb(); /* Ensure update-side operation after counter increment. */
+	WARN_ON_ONCE(rcu_seq_state(*sp) != 1);
+}
+
+/* Compute the end-of-grace-period value for the specified sequence number. */
+static inline unsigned long rcu_seq_endval(unsigned long *sp)
+{
+	return (*sp | RCU_SEQ_STATE_MASK) + 1;
+}
+
+/* Adjust sequence number for end of update-side operation. */
+static inline void rcu_seq_end(unsigned long *sp)
+{
+	smp_mb(); /* Ensure update-side operation before counter increment. */
+	WARN_ON_ONCE(!rcu_seq_state(*sp));
+	WRITE_ONCE(*sp, rcu_seq_endval(sp));
+}
+
+/*
+ * rcu_seq_snap - Take a snapshot of the update side's sequence number.
+ *
+ * This function returns the earliest value of the grace-period sequence number
+ * that will indicate that a full grace period has elapsed since the current
+ * time.  Once the grace-period sequence number has reached this value, it will
+ * be safe to invoke all callbacks that have been registered prior to the
+ * current time. This value is the current grace-period number plus two to the
+ * power of the number of low-order bits reserved for state, then rounded up to
+ * the next value in which the state bits are all zero.
+ */
+static inline unsigned long rcu_seq_snap(unsigned long *sp)
+{
+	unsigned long s;
+
+	s = (READ_ONCE(*sp) + 2 * RCU_SEQ_STATE_MASK + 1) & ~RCU_SEQ_STATE_MASK;
+	smp_mb(); /* Above access must not bleed into critical section. */
+	return s;
+}
+
+/* Return the current value the update side's sequence number, no ordering. */
+static inline unsigned long rcu_seq_current(unsigned long *sp)
+{
+	return READ_ONCE(*sp);
+}
+
+/*
+ * Given a snapshot from rcu_seq_snap(), determine whether or not the
+ * corresponding update-side operation has started.
+ */
+static inline bool rcu_seq_started(unsigned long *sp, unsigned long s)
+{
+	return ULONG_CMP_LT((s - 1) & ~RCU_SEQ_STATE_MASK, READ_ONCE(*sp));
+}
+
+/*
+ * Given a snapshot from rcu_seq_snap(), determine whether or not a
+ * full update-side operation has occurred.
+ */
+static inline bool rcu_seq_done(unsigned long *sp, unsigned long s)
+{
+	return ULONG_CMP_GE(READ_ONCE(*sp), s);
+}
+
+/*
+ * Given a snapshot from rcu_seq_snap(), determine whether or not a
+ * full update-side operation has occurred, but do not allow the
+ * (ULONG_MAX / 2) safety-factor/guard-band.
+ */
+static inline bool rcu_seq_done_exact(unsigned long *sp, unsigned long s)
+{
+	unsigned long cur_s = READ_ONCE(*sp);
+
+	return ULONG_CMP_GE(cur_s, s) || ULONG_CMP_LT(cur_s, s - (2 * RCU_SEQ_STATE_MASK + 1));
+}
+
+/*
+ * Has a grace period completed since the time the old gp_seq was collected?
+ */
+static inline bool rcu_seq_completed_gp(unsigned long old, unsigned long new)
+{
+	return ULONG_CMP_LT(old, new & ~RCU_SEQ_STATE_MASK);
+}
+
+/*
+ * Has a grace period started since the time the old gp_seq was collected?
+ */
+static inline bool rcu_seq_new_gp(unsigned long old, unsigned long new)
+{
+	return ULONG_CMP_LT((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK,
+			    new);
+}
+
+/*
+ * Roughly how many full grace periods have elapsed between the collection
+ * of the two specified grace periods?
+ */
+static inline unsigned long rcu_seq_diff(unsigned long new, unsigned long old)
+{
+	unsigned long rnd_diff;
+
+	if (old == new)
+		return 0;
+	/*
+	 * Compute the number of grace periods (still shifted up), plus
+	 * one if either of new and old is not an exact grace period.
+	 */
+	rnd_diff = (new & ~RCU_SEQ_STATE_MASK) -
+		   ((old + RCU_SEQ_STATE_MASK) & ~RCU_SEQ_STATE_MASK) +
+		   ((new & RCU_SEQ_STATE_MASK) || (old & RCU_SEQ_STATE_MASK));
+	if (ULONG_CMP_GE(RCU_SEQ_STATE_MASK, rnd_diff))
+		return 1; /* Definitely no grace period has elapsed. */
+	return ((rnd_diff - RCU_SEQ_STATE_MASK - 1) >> RCU_SEQ_CTR_SHIFT) + 2;
+}
+
+/*
+ * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally
+ * by call_rcu() and rcu callback execution, and are therefore not part
+ * of the RCU API. These are in rcupdate.h because they are used by all
+ * RCU implementations.
+ */
+
+#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
+# define STATE_RCU_HEAD_READY	0
+# define STATE_RCU_HEAD_QUEUED	1
+
+extern const struct debug_obj_descr rcuhead_debug_descr;
+
+static inline int debug_rcu_head_queue(struct rcu_head *head)
+{
+	int r1;
+
+	r1 = debug_object_activate(head, &rcuhead_debug_descr);
+	debug_object_active_state(head, &rcuhead_debug_descr,
+				  STATE_RCU_HEAD_READY,
+				  STATE_RCU_HEAD_QUEUED);
+	return r1;
+}
+
+static inline void debug_rcu_head_unqueue(struct rcu_head *head)
+{
+	debug_object_active_state(head, &rcuhead_debug_descr,
+				  STATE_RCU_HEAD_QUEUED,
+				  STATE_RCU_HEAD_READY);
+	debug_object_deactivate(head, &rcuhead_debug_descr);
+}
+#else	/* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+static inline int debug_rcu_head_queue(struct rcu_head *head)
+{
+	return 0;
+}
+
+static inline void debug_rcu_head_unqueue(struct rcu_head *head)
+{
+}
+#endif	/* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+
+extern int rcu_cpu_stall_suppress_at_boot;
+
+static inline bool rcu_stall_is_suppressed_at_boot(void)
+{
+	return rcu_cpu_stall_suppress_at_boot && !rcu_inkernel_boot_has_ended();
+}
+
+#ifdef CONFIG_RCU_STALL_COMMON
+
+extern int rcu_cpu_stall_ftrace_dump;
+extern int rcu_cpu_stall_suppress;
+extern int rcu_cpu_stall_timeout;
+extern int rcu_exp_cpu_stall_timeout;
+int rcu_jiffies_till_stall_check(void);
+int rcu_exp_jiffies_till_stall_check(void);
+
+static inline bool rcu_stall_is_suppressed(void)
+{
+	return rcu_stall_is_suppressed_at_boot() || rcu_cpu_stall_suppress;
+}
+
+#define rcu_ftrace_dump_stall_suppress() \
+do { \
+	if (!rcu_cpu_stall_suppress) \
+		rcu_cpu_stall_suppress = 3; \
+} while (0)
+
+#define rcu_ftrace_dump_stall_unsuppress() \
+do { \
+	if (rcu_cpu_stall_suppress == 3) \
+		rcu_cpu_stall_suppress = 0; \
+} while (0)
+
+#else /* #endif #ifdef CONFIG_RCU_STALL_COMMON */
+
+static inline bool rcu_stall_is_suppressed(void)
+{
+	return rcu_stall_is_suppressed_at_boot();
+}
+#define rcu_ftrace_dump_stall_suppress()
+#define rcu_ftrace_dump_stall_unsuppress()
+#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
+
+/*
+ * Strings used in tracepoints need to be exported via the
+ * tracing system such that tools like perf and trace-cmd can
+ * translate the string address pointers to actual text.
+ */
+#define TPS(x)  tracepoint_string(x)
+
+/*
+ * Dump the ftrace buffer, but only one time per callsite per boot.
+ */
+#define rcu_ftrace_dump(oops_dump_mode) \
+do { \
+	static atomic_t ___rfd_beenhere = ATOMIC_INIT(0); \
+	\
+	if (!atomic_read(&___rfd_beenhere) && \
+	    !atomic_xchg(&___rfd_beenhere, 1)) { \
+		tracing_off(); \
+		rcu_ftrace_dump_stall_suppress(); \
+		ftrace_dump(oops_dump_mode); \
+		rcu_ftrace_dump_stall_unsuppress(); \
+	} \
+} while (0)
+
+void rcu_early_boot_tests(void);
+void rcu_test_sync_prims(void);
+
+/*
+ * This function really isn't for public consumption, but RCU is special in
+ * that context switches can allow the state machine to make progress.
+ */
+extern void resched_cpu(int cpu);
+
+#if defined(CONFIG_SRCU) || !defined(CONFIG_TINY_RCU)
+
+#include <linux/rcu_node_tree.h>
+
+extern int rcu_num_lvls;
+extern int num_rcu_lvl[];
+extern int rcu_num_nodes;
+static bool rcu_fanout_exact;
+static int rcu_fanout_leaf;
+
+/*
+ * Compute the per-level fanout, either using the exact fanout specified
+ * or balancing the tree, depending on the rcu_fanout_exact boot parameter.
+ */
+static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
+{
+	int i;
+
+	for (i = 0; i < RCU_NUM_LVLS; i++)
+		levelspread[i] = INT_MIN;
+	if (rcu_fanout_exact) {
+		levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf;
+		for (i = rcu_num_lvls - 2; i >= 0; i--)
+			levelspread[i] = RCU_FANOUT;
+	} else {
+		int ccur;
+		int cprv;
+
+		cprv = nr_cpu_ids;
+		for (i = rcu_num_lvls - 1; i >= 0; i--) {
+			ccur = levelcnt[i];
+			levelspread[i] = (cprv + ccur - 1) / ccur;
+			cprv = ccur;
+		}
+	}
+}
+
+extern void rcu_init_geometry(void);
+
+/* Returns a pointer to the first leaf rcu_node structure. */
+#define rcu_first_leaf_node() (rcu_state.level[rcu_num_lvls - 1])
+
+/* Is this rcu_node a leaf? */
+#define rcu_is_leaf_node(rnp) ((rnp)->level == rcu_num_lvls - 1)
+
+/* Is this rcu_node the last leaf? */
+#define rcu_is_last_leaf_node(rnp) ((rnp) == &rcu_state.node[rcu_num_nodes - 1])
+
+/*
+ * Do a full breadth-first scan of the {s,}rcu_node structures for the
+ * specified state structure (for SRCU) or the only rcu_state structure
+ * (for RCU).
+ */
+#define srcu_for_each_node_breadth_first(sp, rnp) \
+	for ((rnp) = &(sp)->node[0]; \
+	     (rnp) < &(sp)->node[rcu_num_nodes]; (rnp)++)
+#define rcu_for_each_node_breadth_first(rnp) \
+	srcu_for_each_node_breadth_first(&rcu_state, rnp)
+
+/*
+ * Scan the leaves of the rcu_node hierarchy for the rcu_state structure.
+ * Note that if there is a singleton rcu_node tree with but one rcu_node
+ * structure, this loop -will- visit the rcu_node structure.  It is still
+ * a leaf node, even if it is also the root node.
+ */
+#define rcu_for_each_leaf_node(rnp) \
+	for ((rnp) = rcu_first_leaf_node(); \
+	     (rnp) < &rcu_state.node[rcu_num_nodes]; (rnp)++)
+
+/*
+ * Iterate over all possible CPUs in a leaf RCU node.
+ */
+#define for_each_leaf_node_possible_cpu(rnp, cpu) \
+	for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
+	     (cpu) = cpumask_next((rnp)->grplo - 1, cpu_possible_mask); \
+	     (cpu) <= rnp->grphi; \
+	     (cpu) = cpumask_next((cpu), cpu_possible_mask))
+
+/*
+ * Iterate over all CPUs in a leaf RCU node's specified mask.
+ */
+#define rcu_find_next_bit(rnp, cpu, mask) \
+	((rnp)->grplo + find_next_bit(&(mask), BITS_PER_LONG, (cpu)))
+#define for_each_leaf_node_cpu_mask(rnp, cpu, mask) \
+	for (WARN_ON_ONCE(!rcu_is_leaf_node(rnp)), \
+	     (cpu) = rcu_find_next_bit((rnp), 0, (mask)); \
+	     (cpu) <= rnp->grphi; \
+	     (cpu) = rcu_find_next_bit((rnp), (cpu) + 1 - (rnp->grplo), (mask)))
+
+/*
+ * Wrappers for the rcu_node::lock acquire and release.
+ *
+ * Because the rcu_nodes form a tree, the tree traversal locking will observe
+ * different lock values, this in turn means that an UNLOCK of one level
+ * followed by a LOCK of another level does not imply a full memory barrier;
+ * and most importantly transitivity is lost.
+ *
+ * In order to restore full ordering between tree levels, augment the regular
+ * lock acquire functions with smp_mb__after_unlock_lock().
+ *
+ * As ->lock of struct rcu_node is a __private field, therefore one should use
+ * these wrappers rather than directly call raw_spin_{lock,unlock}* on ->lock.
+ */
+#define raw_spin_lock_rcu_node(p)					\
+do {									\
+	raw_spin_lock(&ACCESS_PRIVATE(p, lock));			\
+	smp_mb__after_unlock_lock();					\
+} while (0)
+
+#define raw_spin_unlock_rcu_node(p)					\
+do {									\
+	lockdep_assert_irqs_disabled();					\
+	raw_spin_unlock(&ACCESS_PRIVATE(p, lock));			\
+} while (0)
+
+#define raw_spin_lock_irq_rcu_node(p)					\
+do {									\
+	raw_spin_lock_irq(&ACCESS_PRIVATE(p, lock));			\
+	smp_mb__after_unlock_lock();					\
+} while (0)
+
+#define raw_spin_unlock_irq_rcu_node(p)					\
+do {									\
+	lockdep_assert_irqs_disabled();					\
+	raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock));			\
+} while (0)
+
+#define raw_spin_lock_irqsave_rcu_node(p, flags)			\
+do {									\
+	raw_spin_lock_irqsave(&ACCESS_PRIVATE(p, lock), flags);	\
+	smp_mb__after_unlock_lock();					\
+} while (0)
+
+#define raw_spin_unlock_irqrestore_rcu_node(p, flags)			\
+do {									\
+	lockdep_assert_irqs_disabled();					\
+	raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags);	\
+} while (0)
+
+#define raw_spin_trylock_rcu_node(p)					\
+({									\
+	bool ___locked = raw_spin_trylock(&ACCESS_PRIVATE(p, lock));	\
+									\
+	if (___locked)							\
+		smp_mb__after_unlock_lock();				\
+	___locked;							\
+})
+
+#define raw_lockdep_assert_held_rcu_node(p)				\
+	lockdep_assert_held(&ACCESS_PRIVATE(p, lock))
+
+#endif /* #if defined(CONFIG_SRCU) || !defined(CONFIG_TINY_RCU) */
+
+#ifdef CONFIG_TINY_RCU
+/* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */
+static inline bool rcu_gp_is_normal(void) { return true; }
+static inline bool rcu_gp_is_expedited(void) { return false; }
+static inline void rcu_expedite_gp(void) { }
+static inline void rcu_unexpedite_gp(void) { }
+static inline void rcu_request_urgent_qs_task(struct task_struct *t) { }
+#else /* #ifdef CONFIG_TINY_RCU */
+bool rcu_gp_is_normal(void);     /* Internal RCU use. */
+bool rcu_gp_is_expedited(void);  /* Internal RCU use. */
+void rcu_expedite_gp(void);
+void rcu_unexpedite_gp(void);
+void rcupdate_announce_bootup_oddness(void);
+#ifdef CONFIG_TASKS_RCU_GENERIC
+void show_rcu_tasks_gp_kthreads(void);
+#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
+static inline void show_rcu_tasks_gp_kthreads(void) {}
+#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
+void rcu_request_urgent_qs_task(struct task_struct *t);
+#endif /* #else #ifdef CONFIG_TINY_RCU */
+
+#define RCU_SCHEDULER_INACTIVE	0
+#define RCU_SCHEDULER_INIT	1
+#define RCU_SCHEDULER_RUNNING	2
+
+enum rcutorture_type {
+	RCU_FLAVOR,
+	RCU_TASKS_FLAVOR,
+	RCU_TASKS_RUDE_FLAVOR,
+	RCU_TASKS_TRACING_FLAVOR,
+	RCU_TRIVIAL_FLAVOR,
+	SRCU_FLAVOR,
+	INVALID_RCU_FLAVOR
+};
+
+#if defined(CONFIG_TREE_RCU)
+void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
+			    unsigned long *gp_seq);
+void do_trace_rcu_torture_read(const char *rcutorturename,
+			       struct rcu_head *rhp,
+			       unsigned long secs,
+			       unsigned long c_old,
+			       unsigned long c);
+void rcu_gp_set_torture_wait(int duration);
+#else
+static inline void rcutorture_get_gp_data(enum rcutorture_type test_type,
+					  int *flags, unsigned long *gp_seq)
+{
+	*flags = 0;
+	*gp_seq = 0;
+}
+#ifdef CONFIG_RCU_TRACE
+void do_trace_rcu_torture_read(const char *rcutorturename,
+			       struct rcu_head *rhp,
+			       unsigned long secs,
+			       unsigned long c_old,
+			       unsigned long c);
+#else
+#define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
+	do { } while (0)
+#endif
+static inline void rcu_gp_set_torture_wait(int duration) { }
+#endif
+
+#if IS_ENABLED(CONFIG_RCU_TORTURE_TEST) || IS_MODULE(CONFIG_RCU_TORTURE_TEST)
+long rcutorture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask);
+#endif
+
+#ifdef CONFIG_TINY_SRCU
+
+static inline void srcutorture_get_gp_data(enum rcutorture_type test_type,
+					   struct srcu_struct *sp, int *flags,
+					   unsigned long *gp_seq)
+{
+	if (test_type != SRCU_FLAVOR)
+		return;
+	*flags = 0;
+	*gp_seq = sp->srcu_idx;
+}
+
+#elif defined(CONFIG_TREE_SRCU)
+
+void srcutorture_get_gp_data(enum rcutorture_type test_type,
+			     struct srcu_struct *sp, int *flags,
+			     unsigned long *gp_seq);
+
+#endif
+
+#ifdef CONFIG_TINY_RCU
+static inline bool rcu_dynticks_zero_in_eqs(int cpu, int *vp) { return false; }
+static inline unsigned long rcu_get_gp_seq(void) { return 0; }
+static inline unsigned long rcu_exp_batches_completed(void) { return 0; }
+static inline unsigned long
+srcu_batches_completed(struct srcu_struct *sp) { return 0; }
+static inline void rcu_force_quiescent_state(void) { }
+static inline bool rcu_check_boost_fail(unsigned long gp_state, int *cpup) { return true; }
+static inline void show_rcu_gp_kthreads(void) { }
+static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
+static inline void rcu_fwd_progress_check(unsigned long j) { }
+static inline void rcu_gp_slow_register(atomic_t *rgssp) { }
+static inline void rcu_gp_slow_unregister(atomic_t *rgssp) { }
+#else /* #ifdef CONFIG_TINY_RCU */
+bool rcu_dynticks_zero_in_eqs(int cpu, int *vp);
+unsigned long rcu_get_gp_seq(void);
+unsigned long rcu_exp_batches_completed(void);
+unsigned long srcu_batches_completed(struct srcu_struct *sp);
+bool rcu_check_boost_fail(unsigned long gp_state, int *cpup);
+void show_rcu_gp_kthreads(void);
+int rcu_get_gp_kthreads_prio(void);
+void rcu_fwd_progress_check(unsigned long j);
+void rcu_force_quiescent_state(void);
+extern struct workqueue_struct *rcu_gp_wq;
+#ifdef CONFIG_RCU_EXP_KTHREAD
+extern struct kthread_worker *rcu_exp_gp_kworker;
+extern struct kthread_worker *rcu_exp_par_gp_kworker;
+#else /* !CONFIG_RCU_EXP_KTHREAD */
+extern struct workqueue_struct *rcu_par_gp_wq;
+#endif /* CONFIG_RCU_EXP_KTHREAD */
+void rcu_gp_slow_register(atomic_t *rgssp);
+void rcu_gp_slow_unregister(atomic_t *rgssp);
+#endif /* #else #ifdef CONFIG_TINY_RCU */
+
+#ifdef CONFIG_RCU_NOCB_CPU
+void rcu_bind_current_to_nocb(void);
+#else
+static inline void rcu_bind_current_to_nocb(void) { }
+#endif
+
+#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RCU)
+void show_rcu_tasks_classic_gp_kthread(void);
+#else
+static inline void show_rcu_tasks_classic_gp_kthread(void) {}
+#endif
+#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_RUDE_RCU)
+void show_rcu_tasks_rude_gp_kthread(void);
+#else
+static inline void show_rcu_tasks_rude_gp_kthread(void) {}
+#endif
+#if !defined(CONFIG_TINY_RCU) && defined(CONFIG_TASKS_TRACE_RCU)
+void show_rcu_tasks_trace_gp_kthread(void);
+#else
+static inline void show_rcu_tasks_trace_gp_kthread(void) {}
+#endif
+
+#ifdef CONFIG_TINY_RCU
+static inline bool rcu_cpu_beenfullyonline(int cpu) { return true; }
+#else
+bool rcu_cpu_beenfullyonline(int cpu);
+#endif
+
+#endif /* __LINUX_RCU_H */
diff --git a/kernel/rcu/rcu_segcblist.c b/kernel/rcu/rcu_segcblist.c
new file mode 100644
index 000000000..c54ea2b6a
--- /dev/null
+++ b/kernel/rcu/rcu_segcblist.c
@@ -0,0 +1,633 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * RCU segmented callback lists, function definitions
+ *
+ * Copyright IBM Corporation, 2017
+ *
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
+ */
+
+#include <linux/cpu.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+#include "rcu_segcblist.h"
+
+/* Initialize simple callback list. */
+void rcu_cblist_init(struct rcu_cblist *rclp)
+{
+	rclp->head = NULL;
+	rclp->tail = &rclp->head;
+	rclp->len = 0;
+}
+
+/*
+ * Enqueue an rcu_head structure onto the specified callback list.
+ */
+void rcu_cblist_enqueue(struct rcu_cblist *rclp, struct rcu_head *rhp)
+{
+	*rclp->tail = rhp;
+	rclp->tail = &rhp->next;
+	WRITE_ONCE(rclp->len, rclp->len + 1);
+}
+
+/*
+ * Flush the second rcu_cblist structure onto the first one, obliterating
+ * any contents of the first.  If rhp is non-NULL, enqueue it as the sole
+ * element of the second rcu_cblist structure, but ensuring that the second
+ * rcu_cblist structure, if initially non-empty, always appears non-empty
+ * throughout the process.  If rdp is NULL, the second rcu_cblist structure
+ * is instead initialized to empty.
+ */
+void rcu_cblist_flush_enqueue(struct rcu_cblist *drclp,
+			      struct rcu_cblist *srclp,
+			      struct rcu_head *rhp)
+{
+	drclp->head = srclp->head;
+	if (drclp->head)
+		drclp->tail = srclp->tail;
+	else
+		drclp->tail = &drclp->head;
+	drclp->len = srclp->len;
+	if (!rhp) {
+		rcu_cblist_init(srclp);
+	} else {
+		rhp->next = NULL;
+		srclp->head = rhp;
+		srclp->tail = &rhp->next;
+		WRITE_ONCE(srclp->len, 1);
+	}
+}
+
+/*
+ * Dequeue the oldest rcu_head structure from the specified callback
+ * list.
+ */
+struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp)
+{
+	struct rcu_head *rhp;
+
+	rhp = rclp->head;
+	if (!rhp)
+		return NULL;
+	rclp->len--;
+	rclp->head = rhp->next;
+	if (!rclp->head)
+		rclp->tail = &rclp->head;
+	return rhp;
+}
+
+/* Set the length of an rcu_segcblist structure. */
+static void rcu_segcblist_set_len(struct rcu_segcblist *rsclp, long v)
+{
+#ifdef CONFIG_RCU_NOCB_CPU
+	atomic_long_set(&rsclp->len, v);
+#else
+	WRITE_ONCE(rsclp->len, v);
+#endif
+}
+
+/* Get the length of a segment of the rcu_segcblist structure. */
+static long rcu_segcblist_get_seglen(struct rcu_segcblist *rsclp, int seg)
+{
+	return READ_ONCE(rsclp->seglen[seg]);
+}
+
+/* Return number of callbacks in segmented callback list by summing seglen. */
+long rcu_segcblist_n_segment_cbs(struct rcu_segcblist *rsclp)
+{
+	long len = 0;
+	int i;
+
+	for (i = RCU_DONE_TAIL; i < RCU_CBLIST_NSEGS; i++)
+		len += rcu_segcblist_get_seglen(rsclp, i);
+
+	return len;
+}
+
+/* Set the length of a segment of the rcu_segcblist structure. */
+static void rcu_segcblist_set_seglen(struct rcu_segcblist *rsclp, int seg, long v)
+{
+	WRITE_ONCE(rsclp->seglen[seg], v);
+}
+
+/* Increase the numeric length of a segment by a specified amount. */
+static void rcu_segcblist_add_seglen(struct rcu_segcblist *rsclp, int seg, long v)
+{
+	WRITE_ONCE(rsclp->seglen[seg], rsclp->seglen[seg] + v);
+}
+
+/* Move from's segment length to to's segment. */
+static void rcu_segcblist_move_seglen(struct rcu_segcblist *rsclp, int from, int to)
+{
+	long len;
+
+	if (from == to)
+		return;
+
+	len = rcu_segcblist_get_seglen(rsclp, from);
+	if (!len)
+		return;
+
+	rcu_segcblist_add_seglen(rsclp, to, len);
+	rcu_segcblist_set_seglen(rsclp, from, 0);
+}
+
+/* Increment segment's length. */
+static void rcu_segcblist_inc_seglen(struct rcu_segcblist *rsclp, int seg)
+{
+	rcu_segcblist_add_seglen(rsclp, seg, 1);
+}
+
+/*
+ * Increase the numeric length of an rcu_segcblist structure by the
+ * specified amount, which can be negative.  This can cause the ->len
+ * field to disagree with the actual number of callbacks on the structure.
+ * This increase is fully ordered with respect to the callers accesses
+ * both before and after.
+ *
+ * So why on earth is a memory barrier required both before and after
+ * the update to the ->len field???
+ *
+ * The reason is that rcu_barrier() locklessly samples each CPU's ->len
+ * field, and if a given CPU's field is zero, avoids IPIing that CPU.
+ * This can of course race with both queuing and invoking of callbacks.
+ * Failing to correctly handle either of these races could result in
+ * rcu_barrier() failing to IPI a CPU that actually had callbacks queued
+ * which rcu_barrier() was obligated to wait on.  And if rcu_barrier()
+ * failed to wait on such a callback, unloading certain kernel modules
+ * would result in calls to functions whose code was no longer present in
+ * the kernel, for but one example.
+ *
+ * Therefore, ->len transitions from 1->0 and 0->1 have to be carefully
+ * ordered with respect with both list modifications and the rcu_barrier().
+ *
+ * The queuing case is CASE 1 and the invoking case is CASE 2.
+ *
+ * CASE 1: Suppose that CPU 0 has no callbacks queued, but invokes
+ * call_rcu() just as CPU 1 invokes rcu_barrier().  CPU 0's ->len field
+ * will transition from 0->1, which is one of the transitions that must
+ * be handled carefully.  Without the full memory barriers after the ->len
+ * update and at the beginning of rcu_barrier(), the following could happen:
+ *
+ * CPU 0				CPU 1
+ *
+ * call_rcu().
+ *					rcu_barrier() sees ->len as 0.
+ * set ->len = 1.
+ *					rcu_barrier() does nothing.
+ *					module is unloaded.
+ * callback invokes unloaded function!
+ *
+ * With the full barriers, any case where rcu_barrier() sees ->len as 0 will
+ * have unambiguously preceded the return from the racing call_rcu(), which
+ * means that this call_rcu() invocation is OK to not wait on.  After all,
+ * you are supposed to make sure that any problematic call_rcu() invocations
+ * happen before the rcu_barrier().
+ *
+ *
+ * CASE 2: Suppose that CPU 0 is invoking its last callback just as
+ * CPU 1 invokes rcu_barrier().  CPU 0's ->len field will transition from
+ * 1->0, which is one of the transitions that must be handled carefully.
+ * Without the full memory barriers before the ->len update and at the
+ * end of rcu_barrier(), the following could happen:
+ *
+ * CPU 0				CPU 1
+ *
+ * start invoking last callback
+ * set ->len = 0 (reordered)
+ *					rcu_barrier() sees ->len as 0
+ *					rcu_barrier() does nothing.
+ *					module is unloaded
+ * callback executing after unloaded!
+ *
+ * With the full barriers, any case where rcu_barrier() sees ->len as 0
+ * will be fully ordered after the completion of the callback function,
+ * so that the module unloading operation is completely safe.
+ *
+ */
+void rcu_segcblist_add_len(struct rcu_segcblist *rsclp, long v)
+{
+#ifdef CONFIG_RCU_NOCB_CPU
+	smp_mb__before_atomic(); // Read header comment above.
+	atomic_long_add(v, &rsclp->len);
+	smp_mb__after_atomic();  // Read header comment above.
+#else
+	smp_mb(); // Read header comment above.
+	WRITE_ONCE(rsclp->len, rsclp->len + v);
+	smp_mb(); // Read header comment above.
+#endif
+}
+
+/*
+ * Increase the numeric length of an rcu_segcblist structure by one.
+ * This can cause the ->len field to disagree with the actual number of
+ * callbacks on the structure.  This increase is fully ordered with respect
+ * to the callers accesses both before and after.
+ */
+void rcu_segcblist_inc_len(struct rcu_segcblist *rsclp)
+{
+	rcu_segcblist_add_len(rsclp, 1);
+}
+
+/*
+ * Initialize an rcu_segcblist structure.
+ */
+void rcu_segcblist_init(struct rcu_segcblist *rsclp)
+{
+	int i;
+
+	BUILD_BUG_ON(RCU_NEXT_TAIL + 1 != ARRAY_SIZE(rsclp->gp_seq));
+	BUILD_BUG_ON(ARRAY_SIZE(rsclp->tails) != ARRAY_SIZE(rsclp->gp_seq));
+	rsclp->head = NULL;
+	for (i = 0; i < RCU_CBLIST_NSEGS; i++) {
+		rsclp->tails[i] = &rsclp->head;
+		rcu_segcblist_set_seglen(rsclp, i, 0);
+	}
+	rcu_segcblist_set_len(rsclp, 0);
+	rcu_segcblist_set_flags(rsclp, SEGCBLIST_ENABLED);
+}
+
+/*
+ * Disable the specified rcu_segcblist structure, so that callbacks can
+ * no longer be posted to it.  This structure must be empty.
+ */
+void rcu_segcblist_disable(struct rcu_segcblist *rsclp)
+{
+	WARN_ON_ONCE(!rcu_segcblist_empty(rsclp));
+	WARN_ON_ONCE(rcu_segcblist_n_cbs(rsclp));
+	rcu_segcblist_clear_flags(rsclp, SEGCBLIST_ENABLED);
+}
+
+/*
+ * Mark the specified rcu_segcblist structure as offloaded (or not)
+ */
+void rcu_segcblist_offload(struct rcu_segcblist *rsclp, bool offload)
+{
+	if (offload)
+		rcu_segcblist_set_flags(rsclp, SEGCBLIST_LOCKING | SEGCBLIST_OFFLOADED);
+	else
+		rcu_segcblist_clear_flags(rsclp, SEGCBLIST_OFFLOADED);
+}
+
+/*
+ * Does the specified rcu_segcblist structure contain callbacks that
+ * are ready to be invoked?
+ */
+bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp)
+{
+	return rcu_segcblist_is_enabled(rsclp) &&
+	       &rsclp->head != READ_ONCE(rsclp->tails[RCU_DONE_TAIL]);
+}
+
+/*
+ * Does the specified rcu_segcblist structure contain callbacks that
+ * are still pending, that is, not yet ready to be invoked?
+ */
+bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp)
+{
+	return rcu_segcblist_is_enabled(rsclp) &&
+	       !rcu_segcblist_restempty(rsclp, RCU_DONE_TAIL);
+}
+
+/*
+ * Return a pointer to the first callback in the specified rcu_segcblist
+ * structure.  This is useful for diagnostics.
+ */
+struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp)
+{
+	if (rcu_segcblist_is_enabled(rsclp))
+		return rsclp->head;
+	return NULL;
+}
+
+/*
+ * Return a pointer to the first pending callback in the specified
+ * rcu_segcblist structure.  This is useful just after posting a given
+ * callback -- if that callback is the first pending callback, then
+ * you cannot rely on someone else having already started up the required
+ * grace period.
+ */
+struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp)
+{
+	if (rcu_segcblist_is_enabled(rsclp))
+		return *rsclp->tails[RCU_DONE_TAIL];
+	return NULL;
+}
+
+/*
+ * Return false if there are no CBs awaiting grace periods, otherwise,
+ * return true and store the nearest waited-upon grace period into *lp.
+ */
+bool rcu_segcblist_nextgp(struct rcu_segcblist *rsclp, unsigned long *lp)
+{
+	if (!rcu_segcblist_pend_cbs(rsclp))
+		return false;
+	*lp = rsclp->gp_seq[RCU_WAIT_TAIL];
+	return true;
+}
+
+/*
+ * Enqueue the specified callback onto the specified rcu_segcblist
+ * structure, updating accounting as needed.  Note that the ->len
+ * field may be accessed locklessly, hence the WRITE_ONCE().
+ * The ->len field is used by rcu_barrier() and friends to determine
+ * if it must post a callback on this structure, and it is OK
+ * for rcu_barrier() to sometimes post callbacks needlessly, but
+ * absolutely not OK for it to ever miss posting a callback.
+ */
+void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
+			   struct rcu_head *rhp)
+{
+	rcu_segcblist_inc_len(rsclp);
+	rcu_segcblist_inc_seglen(rsclp, RCU_NEXT_TAIL);
+	rhp->next = NULL;
+	WRITE_ONCE(*rsclp->tails[RCU_NEXT_TAIL], rhp);
+	WRITE_ONCE(rsclp->tails[RCU_NEXT_TAIL], &rhp->next);
+}
+
+/*
+ * Entrain the specified callback onto the specified rcu_segcblist at
+ * the end of the last non-empty segment.  If the entire rcu_segcblist
+ * is empty, make no change, but return false.
+ *
+ * This is intended for use by rcu_barrier()-like primitives, -not-
+ * for normal grace-period use.  IMPORTANT:  The callback you enqueue
+ * will wait for all prior callbacks, NOT necessarily for a grace
+ * period.  You have been warned.
+ */
+bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
+			   struct rcu_head *rhp)
+{
+	int i;
+
+	if (rcu_segcblist_n_cbs(rsclp) == 0)
+		return false;
+	rcu_segcblist_inc_len(rsclp);
+	smp_mb(); /* Ensure counts are updated before callback is entrained. */
+	rhp->next = NULL;
+	for (i = RCU_NEXT_TAIL; i > RCU_DONE_TAIL; i--)
+		if (rsclp->tails[i] != rsclp->tails[i - 1])
+			break;
+	rcu_segcblist_inc_seglen(rsclp, i);
+	WRITE_ONCE(*rsclp->tails[i], rhp);
+	for (; i <= RCU_NEXT_TAIL; i++)
+		WRITE_ONCE(rsclp->tails[i], &rhp->next);
+	return true;
+}
+
+/*
+ * Extract only those callbacks ready to be invoked from the specified
+ * rcu_segcblist structure and place them in the specified rcu_cblist
+ * structure.
+ */
+void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp,
+				    struct rcu_cblist *rclp)
+{
+	int i;
+
+	if (!rcu_segcblist_ready_cbs(rsclp))
+		return; /* Nothing to do. */
+	rclp->len = rcu_segcblist_get_seglen(rsclp, RCU_DONE_TAIL);
+	*rclp->tail = rsclp->head;
+	WRITE_ONCE(rsclp->head, *rsclp->tails[RCU_DONE_TAIL]);
+	WRITE_ONCE(*rsclp->tails[RCU_DONE_TAIL], NULL);
+	rclp->tail = rsclp->tails[RCU_DONE_TAIL];
+	for (i = RCU_CBLIST_NSEGS - 1; i >= RCU_DONE_TAIL; i--)
+		if (rsclp->tails[i] == rsclp->tails[RCU_DONE_TAIL])
+			WRITE_ONCE(rsclp->tails[i], &rsclp->head);
+	rcu_segcblist_set_seglen(rsclp, RCU_DONE_TAIL, 0);
+}
+
+/*
+ * Extract only those callbacks still pending (not yet ready to be
+ * invoked) from the specified rcu_segcblist structure and place them in
+ * the specified rcu_cblist structure.  Note that this loses information
+ * about any callbacks that might have been partway done waiting for
+ * their grace period.  Too bad!  They will have to start over.
+ */
+void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp,
+				    struct rcu_cblist *rclp)
+{
+	int i;
+
+	if (!rcu_segcblist_pend_cbs(rsclp))
+		return; /* Nothing to do. */
+	rclp->len = 0;
+	*rclp->tail = *rsclp->tails[RCU_DONE_TAIL];
+	rclp->tail = rsclp->tails[RCU_NEXT_TAIL];
+	WRITE_ONCE(*rsclp->tails[RCU_DONE_TAIL], NULL);
+	for (i = RCU_DONE_TAIL + 1; i < RCU_CBLIST_NSEGS; i++) {
+		rclp->len += rcu_segcblist_get_seglen(rsclp, i);
+		WRITE_ONCE(rsclp->tails[i], rsclp->tails[RCU_DONE_TAIL]);
+		rcu_segcblist_set_seglen(rsclp, i, 0);
+	}
+}
+
+/*
+ * Insert counts from the specified rcu_cblist structure in the
+ * specified rcu_segcblist structure.
+ */
+void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp,
+				struct rcu_cblist *rclp)
+{
+	rcu_segcblist_add_len(rsclp, rclp->len);
+}
+
+/*
+ * Move callbacks from the specified rcu_cblist to the beginning of the
+ * done-callbacks segment of the specified rcu_segcblist.
+ */
+void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp,
+				   struct rcu_cblist *rclp)
+{
+	int i;
+
+	if (!rclp->head)
+		return; /* No callbacks to move. */
+	rcu_segcblist_add_seglen(rsclp, RCU_DONE_TAIL, rclp->len);
+	*rclp->tail = rsclp->head;
+	WRITE_ONCE(rsclp->head, rclp->head);
+	for (i = RCU_DONE_TAIL; i < RCU_CBLIST_NSEGS; i++)
+		if (&rsclp->head == rsclp->tails[i])
+			WRITE_ONCE(rsclp->tails[i], rclp->tail);
+		else
+			break;
+	rclp->head = NULL;
+	rclp->tail = &rclp->head;
+}
+
+/*
+ * Move callbacks from the specified rcu_cblist to the end of the
+ * new-callbacks segment of the specified rcu_segcblist.
+ */
+void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp,
+				   struct rcu_cblist *rclp)
+{
+	if (!rclp->head)
+		return; /* Nothing to do. */
+
+	rcu_segcblist_add_seglen(rsclp, RCU_NEXT_TAIL, rclp->len);
+	WRITE_ONCE(*rsclp->tails[RCU_NEXT_TAIL], rclp->head);
+	WRITE_ONCE(rsclp->tails[RCU_NEXT_TAIL], rclp->tail);
+}
+
+/*
+ * Advance the callbacks in the specified rcu_segcblist structure based
+ * on the current value passed in for the grace-period counter.
+ */
+void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq)
+{
+	int i, j;
+
+	WARN_ON_ONCE(!rcu_segcblist_is_enabled(rsclp));
+	if (rcu_segcblist_restempty(rsclp, RCU_DONE_TAIL))
+		return;
+
+	/*
+	 * Find all callbacks whose ->gp_seq numbers indicate that they
+	 * are ready to invoke, and put them into the RCU_DONE_TAIL segment.
+	 */
+	for (i = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++) {
+		if (ULONG_CMP_LT(seq, rsclp->gp_seq[i]))
+			break;
+		WRITE_ONCE(rsclp->tails[RCU_DONE_TAIL], rsclp->tails[i]);
+		rcu_segcblist_move_seglen(rsclp, i, RCU_DONE_TAIL);
+	}
+
+	/* If no callbacks moved, nothing more need be done. */
+	if (i == RCU_WAIT_TAIL)
+		return;
+
+	/* Clean up tail pointers that might have been misordered above. */
+	for (j = RCU_WAIT_TAIL; j < i; j++)
+		WRITE_ONCE(rsclp->tails[j], rsclp->tails[RCU_DONE_TAIL]);
+
+	/*
+	 * Callbacks moved, so there might be an empty RCU_WAIT_TAIL
+	 * and a non-empty RCU_NEXT_READY_TAIL.  If so, copy the
+	 * RCU_NEXT_READY_TAIL segment to fill the RCU_WAIT_TAIL gap
+	 * created by the now-ready-to-invoke segments.
+	 */
+	for (j = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++, j++) {
+		if (rsclp->tails[j] == rsclp->tails[RCU_NEXT_TAIL])
+			break;  /* No more callbacks. */
+		WRITE_ONCE(rsclp->tails[j], rsclp->tails[i]);
+		rcu_segcblist_move_seglen(rsclp, i, j);
+		rsclp->gp_seq[j] = rsclp->gp_seq[i];
+	}
+}
+
+/*
+ * "Accelerate" callbacks based on more-accurate grace-period information.
+ * The reason for this is that RCU does not synchronize the beginnings and
+ * ends of grace periods, and that callbacks are posted locally.  This in
+ * turn means that the callbacks must be labelled conservatively early
+ * on, as getting exact information would degrade both performance and
+ * scalability.  When more accurate grace-period information becomes
+ * available, previously posted callbacks can be "accelerated", marking
+ * them to complete at the end of the earlier grace period.
+ *
+ * This function operates on an rcu_segcblist structure, and also the
+ * grace-period sequence number seq at which new callbacks would become
+ * ready to invoke.  Returns true if there are callbacks that won't be
+ * ready to invoke until seq, false otherwise.
+ */
+bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq)
+{
+	int i, j;
+
+	WARN_ON_ONCE(!rcu_segcblist_is_enabled(rsclp));
+	if (rcu_segcblist_restempty(rsclp, RCU_DONE_TAIL))
+		return false;
+
+	/*
+	 * Find the segment preceding the oldest segment of callbacks
+	 * whose ->gp_seq[] completion is at or after that passed in via
+	 * "seq", skipping any empty segments.  This oldest segment, along
+	 * with any later segments, can be merged in with any newly arrived
+	 * callbacks in the RCU_NEXT_TAIL segment, and assigned "seq"
+	 * as their ->gp_seq[] grace-period completion sequence number.
+	 */
+	for (i = RCU_NEXT_READY_TAIL; i > RCU_DONE_TAIL; i--)
+		if (rsclp->tails[i] != rsclp->tails[i - 1] &&
+		    ULONG_CMP_LT(rsclp->gp_seq[i], seq))
+			break;
+
+	/*
+	 * If all the segments contain callbacks that correspond to
+	 * earlier grace-period sequence numbers than "seq", leave.
+	 * Assuming that the rcu_segcblist structure has enough
+	 * segments in its arrays, this can only happen if some of
+	 * the non-done segments contain callbacks that really are
+	 * ready to invoke.  This situation will get straightened
+	 * out by the next call to rcu_segcblist_advance().
+	 *
+	 * Also advance to the oldest segment of callbacks whose
+	 * ->gp_seq[] completion is at or after that passed in via "seq",
+	 * skipping any empty segments.
+	 *
+	 * Note that segment "i" (and any lower-numbered segments
+	 * containing older callbacks) will be unaffected, and their
+	 * grace-period numbers remain unchanged.  For example, if i ==
+	 * WAIT_TAIL, then neither WAIT_TAIL nor DONE_TAIL will be touched.
+	 * Instead, the CBs in NEXT_TAIL will be merged with those in
+	 * NEXT_READY_TAIL and the grace-period number of NEXT_READY_TAIL
+	 * would be updated.  NEXT_TAIL would then be empty.
+	 */
+	if (rcu_segcblist_restempty(rsclp, i) || ++i >= RCU_NEXT_TAIL)
+		return false;
+
+	/* Accounting: everything below i is about to get merged into i. */
+	for (j = i + 1; j <= RCU_NEXT_TAIL; j++)
+		rcu_segcblist_move_seglen(rsclp, j, i);
+
+	/*
+	 * Merge all later callbacks, including newly arrived callbacks,
+	 * into the segment located by the for-loop above.  Assign "seq"
+	 * as the ->gp_seq[] value in order to correctly handle the case
+	 * where there were no pending callbacks in the rcu_segcblist
+	 * structure other than in the RCU_NEXT_TAIL segment.
+	 */
+	for (; i < RCU_NEXT_TAIL; i++) {
+		WRITE_ONCE(rsclp->tails[i], rsclp->tails[RCU_NEXT_TAIL]);
+		rsclp->gp_seq[i] = seq;
+	}
+	return true;
+}
+
+/*
+ * Merge the source rcu_segcblist structure into the destination
+ * rcu_segcblist structure, then initialize the source.  Any pending
+ * callbacks from the source get to start over.  It is best to
+ * advance and accelerate both the destination and the source
+ * before merging.
+ */
+void rcu_segcblist_merge(struct rcu_segcblist *dst_rsclp,
+			 struct rcu_segcblist *src_rsclp)
+{
+	struct rcu_cblist donecbs;
+	struct rcu_cblist pendcbs;
+
+	lockdep_assert_cpus_held();
+
+	rcu_cblist_init(&donecbs);
+	rcu_cblist_init(&pendcbs);
+
+	rcu_segcblist_extract_done_cbs(src_rsclp, &donecbs);
+	rcu_segcblist_extract_pend_cbs(src_rsclp, &pendcbs);
+
+	/*
+	 * No need smp_mb() before setting length to 0, because CPU hotplug
+	 * lock excludes rcu_barrier.
+	 */
+	rcu_segcblist_set_len(src_rsclp, 0);
+
+	rcu_segcblist_insert_count(dst_rsclp, &donecbs);
+	rcu_segcblist_insert_count(dst_rsclp, &pendcbs);
+	rcu_segcblist_insert_done_cbs(dst_rsclp, &donecbs);
+	rcu_segcblist_insert_pend_cbs(dst_rsclp, &pendcbs);
+
+	rcu_segcblist_init(src_rsclp);
+}
diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h
new file mode 100644
index 000000000..431cee212
--- /dev/null
+++ b/kernel/rcu/rcu_segcblist.h
@@ -0,0 +1,153 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * RCU segmented callback lists, internal-to-rcu header file
+ *
+ * Copyright IBM Corporation, 2017
+ *
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
+ */
+
+#include <linux/rcu_segcblist.h>
+
+/* Return number of callbacks in the specified callback list. */
+static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp)
+{
+	return READ_ONCE(rclp->len);
+}
+
+/* Return number of callbacks in segmented callback list by summing seglen. */
+long rcu_segcblist_n_segment_cbs(struct rcu_segcblist *rsclp);
+
+void rcu_cblist_init(struct rcu_cblist *rclp);
+void rcu_cblist_enqueue(struct rcu_cblist *rclp, struct rcu_head *rhp);
+void rcu_cblist_flush_enqueue(struct rcu_cblist *drclp,
+			      struct rcu_cblist *srclp,
+			      struct rcu_head *rhp);
+struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp);
+
+/*
+ * Is the specified rcu_segcblist structure empty?
+ *
+ * But careful!  The fact that the ->head field is NULL does not
+ * necessarily imply that there are no callbacks associated with
+ * this structure.  When callbacks are being invoked, they are
+ * removed as a group.  If callback invocation must be preempted,
+ * the remaining callbacks will be added back to the list.  Either
+ * way, the counts are updated later.
+ *
+ * So it is often the case that rcu_segcblist_n_cbs() should be used
+ * instead.
+ */
+static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp)
+{
+	return !READ_ONCE(rsclp->head);
+}
+
+/* Return number of callbacks in segmented callback list. */
+static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
+{
+#ifdef CONFIG_RCU_NOCB_CPU
+	return atomic_long_read(&rsclp->len);
+#else
+	return READ_ONCE(rsclp->len);
+#endif
+}
+
+static inline void rcu_segcblist_set_flags(struct rcu_segcblist *rsclp,
+					   int flags)
+{
+	WRITE_ONCE(rsclp->flags, rsclp->flags | flags);
+}
+
+static inline void rcu_segcblist_clear_flags(struct rcu_segcblist *rsclp,
+					     int flags)
+{
+	WRITE_ONCE(rsclp->flags, rsclp->flags & ~flags);
+}
+
+static inline bool rcu_segcblist_test_flags(struct rcu_segcblist *rsclp,
+					    int flags)
+{
+	return READ_ONCE(rsclp->flags) & flags;
+}
+
+/*
+ * Is the specified rcu_segcblist enabled, for example, not corresponding
+ * to an offline CPU?
+ */
+static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
+{
+	return rcu_segcblist_test_flags(rsclp, SEGCBLIST_ENABLED);
+}
+
+/*
+ * Is the specified rcu_segcblist NOCB offloaded (or in the middle of the
+ * [de]offloading process)?
+ */
+static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
+{
+	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
+	    rcu_segcblist_test_flags(rsclp, SEGCBLIST_LOCKING))
+		return true;
+
+	return false;
+}
+
+static inline bool rcu_segcblist_completely_offloaded(struct rcu_segcblist *rsclp)
+{
+	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
+	    !rcu_segcblist_test_flags(rsclp, SEGCBLIST_RCU_CORE))
+		return true;
+
+	return false;
+}
+
+/*
+ * Are all segments following the specified segment of the specified
+ * rcu_segcblist structure empty of callbacks?  (The specified
+ * segment might well contain callbacks.)
+ */
+static inline bool rcu_segcblist_restempty(struct rcu_segcblist *rsclp, int seg)
+{
+	return !READ_ONCE(*READ_ONCE(rsclp->tails[seg]));
+}
+
+/*
+ * Is the specified segment of the specified rcu_segcblist structure
+ * empty of callbacks?
+ */
+static inline bool rcu_segcblist_segempty(struct rcu_segcblist *rsclp, int seg)
+{
+	if (seg == RCU_DONE_TAIL)
+		return &rsclp->head == rsclp->tails[RCU_DONE_TAIL];
+	return rsclp->tails[seg - 1] == rsclp->tails[seg];
+}
+
+void rcu_segcblist_inc_len(struct rcu_segcblist *rsclp);
+void rcu_segcblist_add_len(struct rcu_segcblist *rsclp, long v);
+void rcu_segcblist_init(struct rcu_segcblist *rsclp);
+void rcu_segcblist_disable(struct rcu_segcblist *rsclp);
+void rcu_segcblist_offload(struct rcu_segcblist *rsclp, bool offload);
+bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp);
+bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp);
+struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp);
+struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp);
+bool rcu_segcblist_nextgp(struct rcu_segcblist *rsclp, unsigned long *lp);
+void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
+			   struct rcu_head *rhp);
+bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
+			   struct rcu_head *rhp);
+void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp,
+				    struct rcu_cblist *rclp);
+void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp,
+				    struct rcu_cblist *rclp);
+void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp,
+				struct rcu_cblist *rclp);
+void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp,
+				   struct rcu_cblist *rclp);
+void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp,
+				   struct rcu_cblist *rclp);
+void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq);
+bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq);
+void rcu_segcblist_merge(struct rcu_segcblist *dst_rsclp,
+			 struct rcu_segcblist *src_rsclp);
diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
new file mode 100644
index 000000000..0b88d9651
--- /dev/null
+++ b/kernel/rcu/rcuscale.c
@@ -0,0 +1,924 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Read-Copy Update module-based scalability-test facility
+ *
+ * Copyright (C) IBM Corporation, 2015
+ *
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
+ */
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/err.h>
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+#include <linux/rcupdate.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <uapi/linux/sched/types.h>
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/moduleparam.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/freezer.h>
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/stat.h>
+#include <linux/srcu.h>
+#include <linux/slab.h>
+#include <asm/byteorder.h>
+#include <linux/torture.h>
+#include <linux/vmalloc.h>
+#include <linux/rcupdate_trace.h>
+
+#include "rcu.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
+
+#define SCALE_FLAG "-scale:"
+#define SCALEOUT_STRING(s) \
+	pr_alert("%s" SCALE_FLAG " %s\n", scale_type, s)
+#define VERBOSE_SCALEOUT_STRING(s) \
+	do { if (verbose) pr_alert("%s" SCALE_FLAG " %s\n", scale_type, s); } while (0)
+#define SCALEOUT_ERRSTRING(s) \
+	pr_alert("%s" SCALE_FLAG "!!! %s\n", scale_type, s)
+
+/*
+ * The intended use cases for the nreaders and nwriters module parameters
+ * are as follows:
+ *
+ * 1.	Specify only the nr_cpus kernel boot parameter.  This will
+ *	set both nreaders and nwriters to the value specified by
+ *	nr_cpus for a mixed reader/writer test.
+ *
+ * 2.	Specify the nr_cpus kernel boot parameter, but set
+ *	rcuscale.nreaders to zero.  This will set nwriters to the
+ *	value specified by nr_cpus for an update-only test.
+ *
+ * 3.	Specify the nr_cpus kernel boot parameter, but set
+ *	rcuscale.nwriters to zero.  This will set nreaders to the
+ *	value specified by nr_cpus for a read-only test.
+ *
+ * Various other use cases may of course be specified.
+ *
+ * Note that this test's readers are intended only as a test load for
+ * the writers.  The reader scalability statistics will be overly
+ * pessimistic due to the per-critical-section interrupt disabling,
+ * test-end checks, and the pair of calls through pointers.
+ */
+
+#ifdef MODULE
+# define RCUSCALE_SHUTDOWN 0
+#else
+# define RCUSCALE_SHUTDOWN 1
+#endif
+
+torture_param(bool, gp_async, false, "Use asynchronous GP wait primitives");
+torture_param(int, gp_async_max, 1000, "Max # outstanding waits per reader");
+torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
+torture_param(int, holdoff, 10, "Holdoff time before test start (s)");
+torture_param(int, nreaders, -1, "Number of RCU reader threads");
+torture_param(int, nwriters, -1, "Number of RCU updater threads");
+torture_param(bool, shutdown, RCUSCALE_SHUTDOWN,
+	      "Shutdown at end of scalability tests.");
+torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
+torture_param(int, writer_holdoff, 0, "Holdoff (us) between GPs, zero to disable");
+torture_param(int, kfree_rcu_test, 0, "Do we run a kfree_rcu() scale test?");
+torture_param(int, kfree_mult, 1, "Multiple of kfree_obj size to allocate.");
+
+static char *scale_type = "rcu";
+module_param(scale_type, charp, 0444);
+MODULE_PARM_DESC(scale_type, "Type of RCU to scalability-test (rcu, srcu, ...)");
+
+static int nrealreaders;
+static int nrealwriters;
+static struct task_struct **writer_tasks;
+static struct task_struct **reader_tasks;
+static struct task_struct *shutdown_task;
+
+static u64 **writer_durations;
+static int *writer_n_durations;
+static atomic_t n_rcu_scale_reader_started;
+static atomic_t n_rcu_scale_writer_started;
+static atomic_t n_rcu_scale_writer_finished;
+static wait_queue_head_t shutdown_wq;
+static u64 t_rcu_scale_writer_started;
+static u64 t_rcu_scale_writer_finished;
+static unsigned long b_rcu_gp_test_started;
+static unsigned long b_rcu_gp_test_finished;
+static DEFINE_PER_CPU(atomic_t, n_async_inflight);
+
+#define MAX_MEAS 10000
+#define MIN_MEAS 100
+
+/*
+ * Operations vector for selecting different types of tests.
+ */
+
+struct rcu_scale_ops {
+	int ptype;
+	void (*init)(void);
+	void (*cleanup)(void);
+	int (*readlock)(void);
+	void (*readunlock)(int idx);
+	unsigned long (*get_gp_seq)(void);
+	unsigned long (*gp_diff)(unsigned long new, unsigned long old);
+	unsigned long (*exp_completed)(void);
+	void (*async)(struct rcu_head *head, rcu_callback_t func);
+	void (*gp_barrier)(void);
+	void (*sync)(void);
+	void (*exp_sync)(void);
+	const char *name;
+};
+
+static struct rcu_scale_ops *cur_ops;
+
+/*
+ * Definitions for rcu scalability testing.
+ */
+
+static int rcu_scale_read_lock(void) __acquires(RCU)
+{
+	rcu_read_lock();
+	return 0;
+}
+
+static void rcu_scale_read_unlock(int idx) __releases(RCU)
+{
+	rcu_read_unlock();
+}
+
+static unsigned long __maybe_unused rcu_no_completed(void)
+{
+	return 0;
+}
+
+static void rcu_sync_scale_init(void)
+{
+}
+
+static struct rcu_scale_ops rcu_ops = {
+	.ptype		= RCU_FLAVOR,
+	.init		= rcu_sync_scale_init,
+	.readlock	= rcu_scale_read_lock,
+	.readunlock	= rcu_scale_read_unlock,
+	.get_gp_seq	= rcu_get_gp_seq,
+	.gp_diff	= rcu_seq_diff,
+	.exp_completed	= rcu_exp_batches_completed,
+	.async		= call_rcu,
+	.gp_barrier	= rcu_barrier,
+	.sync		= synchronize_rcu,
+	.exp_sync	= synchronize_rcu_expedited,
+	.name		= "rcu"
+};
+
+/*
+ * Definitions for srcu scalability testing.
+ */
+
+DEFINE_STATIC_SRCU(srcu_ctl_scale);
+static struct srcu_struct *srcu_ctlp = &srcu_ctl_scale;
+
+static int srcu_scale_read_lock(void) __acquires(srcu_ctlp)
+{
+	return srcu_read_lock(srcu_ctlp);
+}
+
+static void srcu_scale_read_unlock(int idx) __releases(srcu_ctlp)
+{
+	srcu_read_unlock(srcu_ctlp, idx);
+}
+
+static unsigned long srcu_scale_completed(void)
+{
+	return srcu_batches_completed(srcu_ctlp);
+}
+
+static void srcu_call_rcu(struct rcu_head *head, rcu_callback_t func)
+{
+	call_srcu(srcu_ctlp, head, func);
+}
+
+static void srcu_rcu_barrier(void)
+{
+	srcu_barrier(srcu_ctlp);
+}
+
+static void srcu_scale_synchronize(void)
+{
+	synchronize_srcu(srcu_ctlp);
+}
+
+static void srcu_scale_synchronize_expedited(void)
+{
+	synchronize_srcu_expedited(srcu_ctlp);
+}
+
+static struct rcu_scale_ops srcu_ops = {
+	.ptype		= SRCU_FLAVOR,
+	.init		= rcu_sync_scale_init,
+	.readlock	= srcu_scale_read_lock,
+	.readunlock	= srcu_scale_read_unlock,
+	.get_gp_seq	= srcu_scale_completed,
+	.gp_diff	= rcu_seq_diff,
+	.exp_completed	= srcu_scale_completed,
+	.async		= srcu_call_rcu,
+	.gp_barrier	= srcu_rcu_barrier,
+	.sync		= srcu_scale_synchronize,
+	.exp_sync	= srcu_scale_synchronize_expedited,
+	.name		= "srcu"
+};
+
+static struct srcu_struct srcud;
+
+static void srcu_sync_scale_init(void)
+{
+	srcu_ctlp = &srcud;
+	init_srcu_struct(srcu_ctlp);
+}
+
+static void srcu_sync_scale_cleanup(void)
+{
+	cleanup_srcu_struct(srcu_ctlp);
+}
+
+static struct rcu_scale_ops srcud_ops = {
+	.ptype		= SRCU_FLAVOR,
+	.init		= srcu_sync_scale_init,
+	.cleanup	= srcu_sync_scale_cleanup,
+	.readlock	= srcu_scale_read_lock,
+	.readunlock	= srcu_scale_read_unlock,
+	.get_gp_seq	= srcu_scale_completed,
+	.gp_diff	= rcu_seq_diff,
+	.exp_completed	= srcu_scale_completed,
+	.async		= srcu_call_rcu,
+	.gp_barrier	= srcu_rcu_barrier,
+	.sync		= srcu_scale_synchronize,
+	.exp_sync	= srcu_scale_synchronize_expedited,
+	.name		= "srcud"
+};
+
+#ifdef CONFIG_TASKS_RCU
+
+/*
+ * Definitions for RCU-tasks scalability testing.
+ */
+
+static int tasks_scale_read_lock(void)
+{
+	return 0;
+}
+
+static void tasks_scale_read_unlock(int idx)
+{
+}
+
+static struct rcu_scale_ops tasks_ops = {
+	.ptype		= RCU_TASKS_FLAVOR,
+	.init		= rcu_sync_scale_init,
+	.readlock	= tasks_scale_read_lock,
+	.readunlock	= tasks_scale_read_unlock,
+	.get_gp_seq	= rcu_no_completed,
+	.gp_diff	= rcu_seq_diff,
+	.async		= call_rcu_tasks,
+	.gp_barrier	= rcu_barrier_tasks,
+	.sync		= synchronize_rcu_tasks,
+	.exp_sync	= synchronize_rcu_tasks,
+	.name		= "tasks"
+};
+
+#define TASKS_OPS &tasks_ops,
+
+#else // #ifdef CONFIG_TASKS_RCU
+
+#define TASKS_OPS
+
+#endif // #else // #ifdef CONFIG_TASKS_RCU
+
+#ifdef CONFIG_TASKS_TRACE_RCU
+
+/*
+ * Definitions for RCU-tasks-trace scalability testing.
+ */
+
+static int tasks_trace_scale_read_lock(void)
+{
+	rcu_read_lock_trace();
+	return 0;
+}
+
+static void tasks_trace_scale_read_unlock(int idx)
+{
+	rcu_read_unlock_trace();
+}
+
+static struct rcu_scale_ops tasks_tracing_ops = {
+	.ptype		= RCU_TASKS_FLAVOR,
+	.init		= rcu_sync_scale_init,
+	.readlock	= tasks_trace_scale_read_lock,
+	.readunlock	= tasks_trace_scale_read_unlock,
+	.get_gp_seq	= rcu_no_completed,
+	.gp_diff	= rcu_seq_diff,
+	.async		= call_rcu_tasks_trace,
+	.gp_barrier	= rcu_barrier_tasks_trace,
+	.sync		= synchronize_rcu_tasks_trace,
+	.exp_sync	= synchronize_rcu_tasks_trace,
+	.name		= "tasks-tracing"
+};
+
+#define TASKS_TRACING_OPS &tasks_tracing_ops,
+
+#else // #ifdef CONFIG_TASKS_TRACE_RCU
+
+#define TASKS_TRACING_OPS
+
+#endif // #else // #ifdef CONFIG_TASKS_TRACE_RCU
+
+static unsigned long rcuscale_seq_diff(unsigned long new, unsigned long old)
+{
+	if (!cur_ops->gp_diff)
+		return new - old;
+	return cur_ops->gp_diff(new, old);
+}
+
+/*
+ * If scalability tests complete, wait for shutdown to commence.
+ */
+static void rcu_scale_wait_shutdown(void)
+{
+	cond_resched_tasks_rcu_qs();
+	if (atomic_read(&n_rcu_scale_writer_finished) < nrealwriters)
+		return;
+	while (!torture_must_stop())
+		schedule_timeout_uninterruptible(1);
+}
+
+/*
+ * RCU scalability reader kthread.  Repeatedly does empty RCU read-side
+ * critical section, minimizing update-side interference.  However, the
+ * point of this test is not to evaluate reader scalability, but instead
+ * to serve as a test load for update-side scalability testing.
+ */
+static int
+rcu_scale_reader(void *arg)
+{
+	unsigned long flags;
+	int idx;
+	long me = (long)arg;
+
+	VERBOSE_SCALEOUT_STRING("rcu_scale_reader task started");
+	set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
+	set_user_nice(current, MAX_NICE);
+	atomic_inc(&n_rcu_scale_reader_started);
+
+	do {
+		local_irq_save(flags);
+		idx = cur_ops->readlock();
+		cur_ops->readunlock(idx);
+		local_irq_restore(flags);
+		rcu_scale_wait_shutdown();
+	} while (!torture_must_stop());
+	torture_kthread_stopping("rcu_scale_reader");
+	return 0;
+}
+
+/*
+ * Callback function for asynchronous grace periods from rcu_scale_writer().
+ */
+static void rcu_scale_async_cb(struct rcu_head *rhp)
+{
+	atomic_dec(this_cpu_ptr(&n_async_inflight));
+	kfree(rhp);
+}
+
+/*
+ * RCU scale writer kthread.  Repeatedly does a grace period.
+ */
+static int
+rcu_scale_writer(void *arg)
+{
+	int i = 0;
+	int i_max;
+	long me = (long)arg;
+	struct rcu_head *rhp = NULL;
+	bool started = false, done = false, alldone = false;
+	u64 t;
+	u64 *wdp;
+	u64 *wdpp = writer_durations[me];
+
+	VERBOSE_SCALEOUT_STRING("rcu_scale_writer task started");
+	WARN_ON(!wdpp);
+	set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
+	current->flags |= PF_NO_SETAFFINITY;
+	sched_set_fifo_low(current);
+
+	if (holdoff)
+		schedule_timeout_idle(holdoff * HZ);
+
+	/*
+	 * Wait until rcu_end_inkernel_boot() is called for normal GP tests
+	 * so that RCU is not always expedited for normal GP tests.
+	 * The system_state test is approximate, but works well in practice.
+	 */
+	while (!gp_exp && system_state != SYSTEM_RUNNING)
+		schedule_timeout_uninterruptible(1);
+
+	t = ktime_get_mono_fast_ns();
+	if (atomic_inc_return(&n_rcu_scale_writer_started) >= nrealwriters) {
+		t_rcu_scale_writer_started = t;
+		if (gp_exp) {
+			b_rcu_gp_test_started =
+				cur_ops->exp_completed() / 2;
+		} else {
+			b_rcu_gp_test_started = cur_ops->get_gp_seq();
+		}
+	}
+
+	do {
+		if (writer_holdoff)
+			udelay(writer_holdoff);
+		wdp = &wdpp[i];
+		*wdp = ktime_get_mono_fast_ns();
+		if (gp_async) {
+retry:
+			if (!rhp)
+				rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
+			if (rhp && atomic_read(this_cpu_ptr(&n_async_inflight)) < gp_async_max) {
+				atomic_inc(this_cpu_ptr(&n_async_inflight));
+				cur_ops->async(rhp, rcu_scale_async_cb);
+				rhp = NULL;
+			} else if (!kthread_should_stop()) {
+				cur_ops->gp_barrier();
+				goto retry;
+			} else {
+				kfree(rhp); /* Because we are stopping. */
+			}
+		} else if (gp_exp) {
+			cur_ops->exp_sync();
+		} else {
+			cur_ops->sync();
+		}
+		t = ktime_get_mono_fast_ns();
+		*wdp = t - *wdp;
+		i_max = i;
+		if (!started &&
+		    atomic_read(&n_rcu_scale_writer_started) >= nrealwriters)
+			started = true;
+		if (!done && i >= MIN_MEAS) {
+			done = true;
+			sched_set_normal(current, 0);
+			pr_alert("%s%s rcu_scale_writer %ld has %d measurements\n",
+				 scale_type, SCALE_FLAG, me, MIN_MEAS);
+			if (atomic_inc_return(&n_rcu_scale_writer_finished) >=
+			    nrealwriters) {
+				schedule_timeout_interruptible(10);
+				rcu_ftrace_dump(DUMP_ALL);
+				SCALEOUT_STRING("Test complete");
+				t_rcu_scale_writer_finished = t;
+				if (gp_exp) {
+					b_rcu_gp_test_finished =
+						cur_ops->exp_completed() / 2;
+				} else {
+					b_rcu_gp_test_finished =
+						cur_ops->get_gp_seq();
+				}
+				if (shutdown) {
+					smp_mb(); /* Assign before wake. */
+					wake_up(&shutdown_wq);
+				}
+			}
+		}
+		if (done && !alldone &&
+		    atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters)
+			alldone = true;
+		if (started && !alldone && i < MAX_MEAS - 1)
+			i++;
+		rcu_scale_wait_shutdown();
+	} while (!torture_must_stop());
+	if (gp_async) {
+		cur_ops->gp_barrier();
+	}
+	writer_n_durations[me] = i_max + 1;
+	torture_kthread_stopping("rcu_scale_writer");
+	return 0;
+}
+
+static void
+rcu_scale_print_module_parms(struct rcu_scale_ops *cur_ops, const char *tag)
+{
+	pr_alert("%s" SCALE_FLAG
+		 "--- %s: nreaders=%d nwriters=%d verbose=%d shutdown=%d\n",
+		 scale_type, tag, nrealreaders, nrealwriters, verbose, shutdown);
+}
+
+/*
+ * Return the number if non-negative.  If -1, the number of CPUs.
+ * If less than -1, that much less than the number of CPUs, but
+ * at least one.
+ */
+static int compute_real(int n)
+{
+	int nr;
+
+	if (n >= 0) {
+		nr = n;
+	} else {
+		nr = num_online_cpus() + 1 + n;
+		if (nr <= 0)
+			nr = 1;
+	}
+	return nr;
+}
+
+/*
+ * kfree_rcu() scalability tests: Start a kfree_rcu() loop on all CPUs for number
+ * of iterations and measure total time and number of GP for all iterations to complete.
+ */
+
+torture_param(int, kfree_nthreads, -1, "Number of threads running loops of kfree_rcu().");
+torture_param(int, kfree_alloc_num, 8000, "Number of allocations and frees done in an iteration.");
+torture_param(int, kfree_loops, 10, "Number of loops doing kfree_alloc_num allocations and frees.");
+torture_param(bool, kfree_rcu_test_double, false, "Do we run a kfree_rcu() double-argument scale test?");
+torture_param(bool, kfree_rcu_test_single, false, "Do we run a kfree_rcu() single-argument scale test?");
+
+static struct task_struct **kfree_reader_tasks;
+static int kfree_nrealthreads;
+static atomic_t n_kfree_scale_thread_started;
+static atomic_t n_kfree_scale_thread_ended;
+
+struct kfree_obj {
+	char kfree_obj[8];
+	struct rcu_head rh;
+};
+
+static int
+kfree_scale_thread(void *arg)
+{
+	int i, loop = 0;
+	long me = (long)arg;
+	struct kfree_obj *alloc_ptr;
+	u64 start_time, end_time;
+	long long mem_begin, mem_during = 0;
+	bool kfree_rcu_test_both;
+	DEFINE_TORTURE_RANDOM(tr);
+
+	VERBOSE_SCALEOUT_STRING("kfree_scale_thread task started");
+	set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
+	set_user_nice(current, MAX_NICE);
+	kfree_rcu_test_both = (kfree_rcu_test_single == kfree_rcu_test_double);
+
+	start_time = ktime_get_mono_fast_ns();
+
+	if (atomic_inc_return(&n_kfree_scale_thread_started) >= kfree_nrealthreads) {
+		if (gp_exp)
+			b_rcu_gp_test_started = cur_ops->exp_completed() / 2;
+		else
+			b_rcu_gp_test_started = cur_ops->get_gp_seq();
+	}
+
+	do {
+		if (!mem_during) {
+			mem_during = mem_begin = si_mem_available();
+		} else if (loop % (kfree_loops / 4) == 0) {
+			mem_during = (mem_during + si_mem_available()) / 2;
+		}
+
+		for (i = 0; i < kfree_alloc_num; i++) {
+			alloc_ptr = kmalloc(kfree_mult * sizeof(struct kfree_obj), GFP_KERNEL);
+			if (!alloc_ptr)
+				return -ENOMEM;
+
+			// By default kfree_rcu_test_single and kfree_rcu_test_double are
+			// initialized to false. If both have the same value (false or true)
+			// both are randomly tested, otherwise only the one with value true
+			// is tested.
+			if ((kfree_rcu_test_single && !kfree_rcu_test_double) ||
+					(kfree_rcu_test_both && torture_random(&tr) & 0x800))
+				kfree_rcu(alloc_ptr);
+			else
+				kfree_rcu(alloc_ptr, rh);
+		}
+
+		cond_resched();
+	} while (!torture_must_stop() && ++loop < kfree_loops);
+
+	if (atomic_inc_return(&n_kfree_scale_thread_ended) >= kfree_nrealthreads) {
+		end_time = ktime_get_mono_fast_ns();
+
+		if (gp_exp)
+			b_rcu_gp_test_finished = cur_ops->exp_completed() / 2;
+		else
+			b_rcu_gp_test_finished = cur_ops->get_gp_seq();
+
+		pr_alert("Total time taken by all kfree'ers: %llu ns, loops: %d, batches: %ld, memory footprint: %lldMB\n",
+		       (unsigned long long)(end_time - start_time), kfree_loops,
+		       rcuscale_seq_diff(b_rcu_gp_test_finished, b_rcu_gp_test_started),
+		       (mem_begin - mem_during) >> (20 - PAGE_SHIFT));
+
+		if (shutdown) {
+			smp_mb(); /* Assign before wake. */
+			wake_up(&shutdown_wq);
+		}
+	}
+
+	torture_kthread_stopping("kfree_scale_thread");
+	return 0;
+}
+
+static void
+kfree_scale_cleanup(void)
+{
+	int i;
+
+	if (torture_cleanup_begin())
+		return;
+
+	if (kfree_reader_tasks) {
+		for (i = 0; i < kfree_nrealthreads; i++)
+			torture_stop_kthread(kfree_scale_thread,
+					     kfree_reader_tasks[i]);
+		kfree(kfree_reader_tasks);
+	}
+
+	torture_cleanup_end();
+}
+
+/*
+ * shutdown kthread.  Just waits to be awakened, then shuts down system.
+ */
+static int
+kfree_scale_shutdown(void *arg)
+{
+	wait_event_idle(shutdown_wq,
+			atomic_read(&n_kfree_scale_thread_ended) >= kfree_nrealthreads);
+
+	smp_mb(); /* Wake before output. */
+
+	kfree_scale_cleanup();
+	kernel_power_off();
+	return -EINVAL;
+}
+
+static int __init
+kfree_scale_init(void)
+{
+	long i;
+	int firsterr = 0;
+
+	kfree_nrealthreads = compute_real(kfree_nthreads);
+	/* Start up the kthreads. */
+	if (shutdown) {
+		init_waitqueue_head(&shutdown_wq);
+		firsterr = torture_create_kthread(kfree_scale_shutdown, NULL,
+						  shutdown_task);
+		if (torture_init_error(firsterr))
+			goto unwind;
+		schedule_timeout_uninterruptible(1);
+	}
+
+	pr_alert("kfree object size=%zu\n", kfree_mult * sizeof(struct kfree_obj));
+
+	kfree_reader_tasks = kcalloc(kfree_nrealthreads, sizeof(kfree_reader_tasks[0]),
+			       GFP_KERNEL);
+	if (kfree_reader_tasks == NULL) {
+		firsterr = -ENOMEM;
+		goto unwind;
+	}
+
+	for (i = 0; i < kfree_nrealthreads; i++) {
+		firsterr = torture_create_kthread(kfree_scale_thread, (void *)i,
+						  kfree_reader_tasks[i]);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+
+	while (atomic_read(&n_kfree_scale_thread_started) < kfree_nrealthreads)
+		schedule_timeout_uninterruptible(1);
+
+	torture_init_end();
+	return 0;
+
+unwind:
+	torture_init_end();
+	kfree_scale_cleanup();
+	return firsterr;
+}
+
+static void
+rcu_scale_cleanup(void)
+{
+	int i;
+	int j;
+	int ngps = 0;
+	u64 *wdp;
+	u64 *wdpp;
+
+	/*
+	 * Would like warning at start, but everything is expedited
+	 * during the mid-boot phase, so have to wait till the end.
+	 */
+	if (rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp)
+		SCALEOUT_ERRSTRING("All grace periods expedited, no normal ones to measure!");
+	if (rcu_gp_is_normal() && gp_exp)
+		SCALEOUT_ERRSTRING("All grace periods normal, no expedited ones to measure!");
+	if (gp_exp && gp_async)
+		SCALEOUT_ERRSTRING("No expedited async GPs, so went with async!");
+
+	if (kfree_rcu_test) {
+		kfree_scale_cleanup();
+		return;
+	}
+
+	if (torture_cleanup_begin())
+		return;
+	if (!cur_ops) {
+		torture_cleanup_end();
+		return;
+	}
+
+	if (reader_tasks) {
+		for (i = 0; i < nrealreaders; i++)
+			torture_stop_kthread(rcu_scale_reader,
+					     reader_tasks[i]);
+		kfree(reader_tasks);
+	}
+
+	if (writer_tasks) {
+		for (i = 0; i < nrealwriters; i++) {
+			torture_stop_kthread(rcu_scale_writer,
+					     writer_tasks[i]);
+			if (!writer_n_durations)
+				continue;
+			j = writer_n_durations[i];
+			pr_alert("%s%s writer %d gps: %d\n",
+				 scale_type, SCALE_FLAG, i, j);
+			ngps += j;
+		}
+		pr_alert("%s%s start: %llu end: %llu duration: %llu gps: %d batches: %ld\n",
+			 scale_type, SCALE_FLAG,
+			 t_rcu_scale_writer_started, t_rcu_scale_writer_finished,
+			 t_rcu_scale_writer_finished -
+			 t_rcu_scale_writer_started,
+			 ngps,
+			 rcuscale_seq_diff(b_rcu_gp_test_finished,
+					   b_rcu_gp_test_started));
+		for (i = 0; i < nrealwriters; i++) {
+			if (!writer_durations)
+				break;
+			if (!writer_n_durations)
+				continue;
+			wdpp = writer_durations[i];
+			if (!wdpp)
+				continue;
+			for (j = 0; j < writer_n_durations[i]; j++) {
+				wdp = &wdpp[j];
+				pr_alert("%s%s %4d writer-duration: %5d %llu\n",
+					scale_type, SCALE_FLAG,
+					i, j, *wdp);
+				if (j % 100 == 0)
+					schedule_timeout_uninterruptible(1);
+			}
+			kfree(writer_durations[i]);
+		}
+		kfree(writer_tasks);
+		kfree(writer_durations);
+		kfree(writer_n_durations);
+	}
+
+	/* Do torture-type-specific cleanup operations.  */
+	if (cur_ops->cleanup != NULL)
+		cur_ops->cleanup();
+
+	torture_cleanup_end();
+}
+
+/*
+ * RCU scalability shutdown kthread.  Just waits to be awakened, then shuts
+ * down system.
+ */
+static int
+rcu_scale_shutdown(void *arg)
+{
+	wait_event_idle(shutdown_wq, atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters);
+	smp_mb(); /* Wake before output. */
+	rcu_scale_cleanup();
+	kernel_power_off();
+	return -EINVAL;
+}
+
+static int __init
+rcu_scale_init(void)
+{
+	long i;
+	int firsterr = 0;
+	static struct rcu_scale_ops *scale_ops[] = {
+		&rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_TRACING_OPS
+	};
+
+	if (!torture_init_begin(scale_type, verbose))
+		return -EBUSY;
+
+	/* Process args and announce that the scalability'er is on the job. */
+	for (i = 0; i < ARRAY_SIZE(scale_ops); i++) {
+		cur_ops = scale_ops[i];
+		if (strcmp(scale_type, cur_ops->name) == 0)
+			break;
+	}
+	if (i == ARRAY_SIZE(scale_ops)) {
+		pr_alert("rcu-scale: invalid scale type: \"%s\"\n", scale_type);
+		pr_alert("rcu-scale types:");
+		for (i = 0; i < ARRAY_SIZE(scale_ops); i++)
+			pr_cont(" %s", scale_ops[i]->name);
+		pr_cont("\n");
+		firsterr = -EINVAL;
+		cur_ops = NULL;
+		goto unwind;
+	}
+	if (cur_ops->init)
+		cur_ops->init();
+
+	if (kfree_rcu_test)
+		return kfree_scale_init();
+
+	nrealwriters = compute_real(nwriters);
+	nrealreaders = compute_real(nreaders);
+	atomic_set(&n_rcu_scale_reader_started, 0);
+	atomic_set(&n_rcu_scale_writer_started, 0);
+	atomic_set(&n_rcu_scale_writer_finished, 0);
+	rcu_scale_print_module_parms(cur_ops, "Start of test");
+
+	/* Start up the kthreads. */
+
+	if (shutdown) {
+		init_waitqueue_head(&shutdown_wq);
+		firsterr = torture_create_kthread(rcu_scale_shutdown, NULL,
+						  shutdown_task);
+		if (torture_init_error(firsterr))
+			goto unwind;
+		schedule_timeout_uninterruptible(1);
+	}
+	reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
+			       GFP_KERNEL);
+	if (reader_tasks == NULL) {
+		SCALEOUT_ERRSTRING("out of memory");
+		firsterr = -ENOMEM;
+		goto unwind;
+	}
+	for (i = 0; i < nrealreaders; i++) {
+		firsterr = torture_create_kthread(rcu_scale_reader, (void *)i,
+						  reader_tasks[i]);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	while (atomic_read(&n_rcu_scale_reader_started) < nrealreaders)
+		schedule_timeout_uninterruptible(1);
+	writer_tasks = kcalloc(nrealwriters, sizeof(reader_tasks[0]),
+			       GFP_KERNEL);
+	writer_durations = kcalloc(nrealwriters, sizeof(*writer_durations),
+				   GFP_KERNEL);
+	writer_n_durations =
+		kcalloc(nrealwriters, sizeof(*writer_n_durations),
+			GFP_KERNEL);
+	if (!writer_tasks || !writer_durations || !writer_n_durations) {
+		SCALEOUT_ERRSTRING("out of memory");
+		firsterr = -ENOMEM;
+		goto unwind;
+	}
+	for (i = 0; i < nrealwriters; i++) {
+		writer_durations[i] =
+			kcalloc(MAX_MEAS, sizeof(*writer_durations[i]),
+				GFP_KERNEL);
+		if (!writer_durations[i]) {
+			firsterr = -ENOMEM;
+			goto unwind;
+		}
+		firsterr = torture_create_kthread(rcu_scale_writer, (void *)i,
+						  writer_tasks[i]);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	torture_init_end();
+	return 0;
+
+unwind:
+	torture_init_end();
+	rcu_scale_cleanup();
+	if (shutdown) {
+		WARN_ON(!IS_MODULE(CONFIG_RCU_SCALE_TEST));
+		kernel_power_off();
+	}
+	return firsterr;
+}
+
+module_init(rcu_scale_init);
+module_exit(rcu_scale_cleanup);
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
new file mode 100644
index 000000000..503c2aa84
--- /dev/null
+++ b/kernel/rcu/rcutorture.c
@@ -0,0 +1,3654 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Read-Copy Update module-based torture test facility
+ *
+ * Copyright (C) IBM Corporation, 2005, 2006
+ *
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
+ *	  Josh Triplett <josh@joshtriplett.org>
+ *
+ * See also:  Documentation/RCU/torture.rst
+ */
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/err.h>
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+#include <linux/rcupdate_wait.h>
+#include <linux/interrupt.h>
+#include <linux/sched/signal.h>
+#include <uapi/linux/sched/types.h>
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/moduleparam.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/freezer.h>
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/stat.h>
+#include <linux/srcu.h>
+#include <linux/slab.h>
+#include <linux/trace_clock.h>
+#include <asm/byteorder.h>
+#include <linux/torture.h>
+#include <linux/vmalloc.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/sysctl.h>
+#include <linux/oom.h>
+#include <linux/tick.h>
+#include <linux/rcupdate_trace.h>
+#include <linux/nmi.h>
+
+#include "rcu.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
+
+/* Bits for ->extendables field, extendables param, and related definitions. */
+#define RCUTORTURE_RDR_SHIFT_1	 8	/* Put SRCU index in upper bits. */
+#define RCUTORTURE_RDR_MASK_1	 (1 << RCUTORTURE_RDR_SHIFT_1)
+#define RCUTORTURE_RDR_SHIFT_2	 9	/* Put SRCU index in upper bits. */
+#define RCUTORTURE_RDR_MASK_2	 (1 << RCUTORTURE_RDR_SHIFT_2)
+#define RCUTORTURE_RDR_BH	 0x01	/* Extend readers by disabling bh. */
+#define RCUTORTURE_RDR_IRQ	 0x02	/*  ... disabling interrupts. */
+#define RCUTORTURE_RDR_PREEMPT	 0x04	/*  ... disabling preemption. */
+#define RCUTORTURE_RDR_RBH	 0x08	/*  ... rcu_read_lock_bh(). */
+#define RCUTORTURE_RDR_SCHED	 0x10	/*  ... rcu_read_lock_sched(). */
+#define RCUTORTURE_RDR_RCU_1	 0x20	/*  ... entering another RCU reader. */
+#define RCUTORTURE_RDR_RCU_2	 0x40	/*  ... entering another RCU reader. */
+#define RCUTORTURE_RDR_NBITS	 7	/* Number of bits defined above. */
+#define RCUTORTURE_MAX_EXTEND	 \
+	(RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
+	 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
+#define RCUTORTURE_RDR_MAX_LOOPS 0x7	/* Maximum reader extensions. */
+					/* Must be power of two minus one. */
+#define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
+
+torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
+	      "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
+torture_param(int, fqs_duration, 0, "Duration of fqs bursts (us), 0 to disable");
+torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
+torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
+torture_param(int, fwd_progress, 1, "Number of grace-period forward progress tasks (0 to disable)");
+torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
+torture_param(int, fwd_progress_holdoff, 60, "Time between forward-progress tests (s)");
+torture_param(bool, fwd_progress_need_resched, 1, "Hide cond_resched() behind need_resched()");
+torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
+torture_param(bool, gp_cond_exp, false, "Use conditional/async expedited GP wait primitives");
+torture_param(bool, gp_cond_full, false, "Use conditional/async full-state GP wait primitives");
+torture_param(bool, gp_cond_exp_full, false,
+		    "Use conditional/async full-stateexpedited GP wait primitives");
+torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
+torture_param(bool, gp_normal, false, "Use normal (non-expedited) GP wait primitives");
+torture_param(bool, gp_poll, false, "Use polling GP wait primitives");
+torture_param(bool, gp_poll_exp, false, "Use polling expedited GP wait primitives");
+torture_param(bool, gp_poll_full, false, "Use polling full-state GP wait primitives");
+torture_param(bool, gp_poll_exp_full, false, "Use polling full-state expedited GP wait primitives");
+torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
+torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
+torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers");
+torture_param(int, n_barrier_cbs, 0, "# of callbacks/kthreads for barrier testing");
+torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
+torture_param(int, nreaders, -1, "Number of RCU reader threads");
+torture_param(int, object_debug, 0, "Enable debug-object double call_rcu() testing");
+torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
+torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (jiffies), 0=disable");
+torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable");
+torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
+torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)");
+torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable");
+torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
+torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
+torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
+torture_param(int, stall_cpu_holdoff, 10, "Time to wait before starting stall (s).");
+torture_param(bool, stall_no_softlockup, false, "Avoid softlockup warning during cpu stall.");
+torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
+torture_param(int, stall_cpu_block, 0, "Sleep while stalling.");
+torture_param(int, stall_gp_kthread, 0, "Grace-period kthread stall duration (s).");
+torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s");
+torture_param(int, stutter, 5, "Number of seconds to run/halt test");
+torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
+torture_param(int, test_boost_duration, 4, "Duration of each boost test, seconds.");
+torture_param(int, test_boost_interval, 7, "Interval between boost tests, seconds.");
+torture_param(bool, test_no_idle_hz, true, "Test support for tickless idle CPUs");
+torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
+
+static char *torture_type = "rcu";
+module_param(torture_type, charp, 0444);
+MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
+
+static int nrealnocbers;
+static int nrealreaders;
+static struct task_struct *writer_task;
+static struct task_struct **fakewriter_tasks;
+static struct task_struct **reader_tasks;
+static struct task_struct **nocb_tasks;
+static struct task_struct *stats_task;
+static struct task_struct *fqs_task;
+static struct task_struct *boost_tasks[NR_CPUS];
+static struct task_struct *stall_task;
+static struct task_struct **fwd_prog_tasks;
+static struct task_struct **barrier_cbs_tasks;
+static struct task_struct *barrier_task;
+static struct task_struct *read_exit_task;
+
+#define RCU_TORTURE_PIPE_LEN 10
+
+// Mailbox-like structure to check RCU global memory ordering.
+struct rcu_torture_reader_check {
+	unsigned long rtc_myloops;
+	int rtc_chkrdr;
+	unsigned long rtc_chkloops;
+	int rtc_ready;
+	struct rcu_torture_reader_check *rtc_assigner;
+} ____cacheline_internodealigned_in_smp;
+
+// Update-side data structure used to check RCU readers.
+struct rcu_torture {
+	struct rcu_head rtort_rcu;
+	int rtort_pipe_count;
+	struct list_head rtort_free;
+	int rtort_mbtest;
+	struct rcu_torture_reader_check *rtort_chkp;
+};
+
+static LIST_HEAD(rcu_torture_freelist);
+static struct rcu_torture __rcu *rcu_torture_current;
+static unsigned long rcu_torture_current_version;
+static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
+static DEFINE_SPINLOCK(rcu_torture_lock);
+static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
+static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
+static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
+static struct rcu_torture_reader_check *rcu_torture_reader_mbchk;
+static atomic_t n_rcu_torture_alloc;
+static atomic_t n_rcu_torture_alloc_fail;
+static atomic_t n_rcu_torture_free;
+static atomic_t n_rcu_torture_mberror;
+static atomic_t n_rcu_torture_mbchk_fail;
+static atomic_t n_rcu_torture_mbchk_tries;
+static atomic_t n_rcu_torture_error;
+static long n_rcu_torture_barrier_error;
+static long n_rcu_torture_boost_ktrerror;
+static long n_rcu_torture_boost_rterror;
+static long n_rcu_torture_boost_failure;
+static long n_rcu_torture_boosts;
+static atomic_long_t n_rcu_torture_timers;
+static long n_barrier_attempts;
+static long n_barrier_successes; /* did rcu_barrier test succeed? */
+static unsigned long n_read_exits;
+static struct list_head rcu_torture_removed;
+static unsigned long shutdown_jiffies;
+static unsigned long start_gp_seq;
+static atomic_long_t n_nocb_offload;
+static atomic_long_t n_nocb_deoffload;
+
+static int rcu_torture_writer_state;
+#define RTWS_FIXED_DELAY	0
+#define RTWS_DELAY		1
+#define RTWS_REPLACE		2
+#define RTWS_DEF_FREE		3
+#define RTWS_EXP_SYNC		4
+#define RTWS_COND_GET		5
+#define RTWS_COND_GET_FULL	6
+#define RTWS_COND_GET_EXP	7
+#define RTWS_COND_GET_EXP_FULL	8
+#define RTWS_COND_SYNC		9
+#define RTWS_COND_SYNC_FULL	10
+#define RTWS_COND_SYNC_EXP	11
+#define RTWS_COND_SYNC_EXP_FULL	12
+#define RTWS_POLL_GET		13
+#define RTWS_POLL_GET_FULL	14
+#define RTWS_POLL_GET_EXP	15
+#define RTWS_POLL_GET_EXP_FULL	16
+#define RTWS_POLL_WAIT		17
+#define RTWS_POLL_WAIT_FULL	18
+#define RTWS_POLL_WAIT_EXP	19
+#define RTWS_POLL_WAIT_EXP_FULL	20
+#define RTWS_SYNC		21
+#define RTWS_STUTTER		22
+#define RTWS_STOPPING		23
+static const char * const rcu_torture_writer_state_names[] = {
+	"RTWS_FIXED_DELAY",
+	"RTWS_DELAY",
+	"RTWS_REPLACE",
+	"RTWS_DEF_FREE",
+	"RTWS_EXP_SYNC",
+	"RTWS_COND_GET",
+	"RTWS_COND_GET_FULL",
+	"RTWS_COND_GET_EXP",
+	"RTWS_COND_GET_EXP_FULL",
+	"RTWS_COND_SYNC",
+	"RTWS_COND_SYNC_FULL",
+	"RTWS_COND_SYNC_EXP",
+	"RTWS_COND_SYNC_EXP_FULL",
+	"RTWS_POLL_GET",
+	"RTWS_POLL_GET_FULL",
+	"RTWS_POLL_GET_EXP",
+	"RTWS_POLL_GET_EXP_FULL",
+	"RTWS_POLL_WAIT",
+	"RTWS_POLL_WAIT_FULL",
+	"RTWS_POLL_WAIT_EXP",
+	"RTWS_POLL_WAIT_EXP_FULL",
+	"RTWS_SYNC",
+	"RTWS_STUTTER",
+	"RTWS_STOPPING",
+};
+
+/* Record reader segment types and duration for first failing read. */
+struct rt_read_seg {
+	int rt_readstate;
+	unsigned long rt_delay_jiffies;
+	unsigned long rt_delay_ms;
+	unsigned long rt_delay_us;
+	bool rt_preempted;
+};
+static int err_segs_recorded;
+static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
+static int rt_read_nsegs;
+
+static const char *rcu_torture_writer_state_getname(void)
+{
+	unsigned int i = READ_ONCE(rcu_torture_writer_state);
+
+	if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
+		return "???";
+	return rcu_torture_writer_state_names[i];
+}
+
+#ifdef CONFIG_RCU_TRACE
+static u64 notrace rcu_trace_clock_local(void)
+{
+	u64 ts = trace_clock_local();
+
+	(void)do_div(ts, NSEC_PER_USEC);
+	return ts;
+}
+#else /* #ifdef CONFIG_RCU_TRACE */
+static u64 notrace rcu_trace_clock_local(void)
+{
+	return 0ULL;
+}
+#endif /* #else #ifdef CONFIG_RCU_TRACE */
+
+/*
+ * Stop aggressive CPU-hog tests a bit before the end of the test in order
+ * to avoid interfering with test shutdown.
+ */
+static bool shutdown_time_arrived(void)
+{
+	return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
+}
+
+static unsigned long boost_starttime;	/* jiffies of next boost test start. */
+static DEFINE_MUTEX(boost_mutex);	/* protect setting boost_starttime */
+					/*  and boost task create/destroy. */
+static atomic_t barrier_cbs_count;	/* Barrier callbacks registered. */
+static bool barrier_phase;		/* Test phase. */
+static atomic_t barrier_cbs_invoked;	/* Barrier callbacks invoked. */
+static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
+static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
+
+static atomic_t rcu_fwd_cb_nodelay;	/* Short rcu_torture_delay() delays. */
+
+/*
+ * Allocate an element from the rcu_tortures pool.
+ */
+static struct rcu_torture *
+rcu_torture_alloc(void)
+{
+	struct list_head *p;
+
+	spin_lock_bh(&rcu_torture_lock);
+	if (list_empty(&rcu_torture_freelist)) {
+		atomic_inc(&n_rcu_torture_alloc_fail);
+		spin_unlock_bh(&rcu_torture_lock);
+		return NULL;
+	}
+	atomic_inc(&n_rcu_torture_alloc);
+	p = rcu_torture_freelist.next;
+	list_del_init(p);
+	spin_unlock_bh(&rcu_torture_lock);
+	return container_of(p, struct rcu_torture, rtort_free);
+}
+
+/*
+ * Free an element to the rcu_tortures pool.
+ */
+static void
+rcu_torture_free(struct rcu_torture *p)
+{
+	atomic_inc(&n_rcu_torture_free);
+	spin_lock_bh(&rcu_torture_lock);
+	list_add_tail(&p->rtort_free, &rcu_torture_freelist);
+	spin_unlock_bh(&rcu_torture_lock);
+}
+
+/*
+ * Operations vector for selecting different types of tests.
+ */
+
+struct rcu_torture_ops {
+	int ttype;
+	void (*init)(void);
+	void (*cleanup)(void);
+	int (*readlock)(void);
+	void (*read_delay)(struct torture_random_state *rrsp,
+			   struct rt_read_seg *rtrsp);
+	void (*readunlock)(int idx);
+	int (*readlock_held)(void);
+	unsigned long (*get_gp_seq)(void);
+	unsigned long (*gp_diff)(unsigned long new, unsigned long old);
+	void (*deferred_free)(struct rcu_torture *p);
+	void (*sync)(void);
+	void (*exp_sync)(void);
+	unsigned long (*get_gp_state_exp)(void);
+	unsigned long (*start_gp_poll_exp)(void);
+	void (*start_gp_poll_exp_full)(struct rcu_gp_oldstate *rgosp);
+	bool (*poll_gp_state_exp)(unsigned long oldstate);
+	void (*cond_sync_exp)(unsigned long oldstate);
+	void (*cond_sync_exp_full)(struct rcu_gp_oldstate *rgosp);
+	unsigned long (*get_gp_state)(void);
+	void (*get_gp_state_full)(struct rcu_gp_oldstate *rgosp);
+	unsigned long (*get_gp_completed)(void);
+	void (*get_gp_completed_full)(struct rcu_gp_oldstate *rgosp);
+	unsigned long (*start_gp_poll)(void);
+	void (*start_gp_poll_full)(struct rcu_gp_oldstate *rgosp);
+	bool (*poll_gp_state)(unsigned long oldstate);
+	bool (*poll_gp_state_full)(struct rcu_gp_oldstate *rgosp);
+	bool (*poll_need_2gp)(bool poll, bool poll_full);
+	void (*cond_sync)(unsigned long oldstate);
+	void (*cond_sync_full)(struct rcu_gp_oldstate *rgosp);
+	call_rcu_func_t call;
+	void (*cb_barrier)(void);
+	void (*fqs)(void);
+	void (*stats)(void);
+	void (*gp_kthread_dbg)(void);
+	bool (*check_boost_failed)(unsigned long gp_state, int *cpup);
+	int (*stall_dur)(void);
+	long cbflood_max;
+	int irq_capable;
+	int can_boost;
+	int extendables;
+	int slow_gps;
+	int no_pi_lock;
+	const char *name;
+};
+
+static struct rcu_torture_ops *cur_ops;
+
+/*
+ * Definitions for rcu torture testing.
+ */
+
+static int torture_readlock_not_held(void)
+{
+	return rcu_read_lock_bh_held() || rcu_read_lock_sched_held();
+}
+
+static int rcu_torture_read_lock(void) __acquires(RCU)
+{
+	rcu_read_lock();
+	return 0;
+}
+
+static void
+rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
+{
+	unsigned long started;
+	unsigned long completed;
+	const unsigned long shortdelay_us = 200;
+	unsigned long longdelay_ms = 300;
+	unsigned long long ts;
+
+	/* We want a short delay sometimes to make a reader delay the grace
+	 * period, and we want a long delay occasionally to trigger
+	 * force_quiescent_state. */
+
+	if (!atomic_read(&rcu_fwd_cb_nodelay) &&
+	    !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
+		started = cur_ops->get_gp_seq();
+		ts = rcu_trace_clock_local();
+		if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK))
+			longdelay_ms = 5; /* Avoid triggering BH limits. */
+		mdelay(longdelay_ms);
+		rtrsp->rt_delay_ms = longdelay_ms;
+		completed = cur_ops->get_gp_seq();
+		do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
+					  started, completed);
+	}
+	if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
+		udelay(shortdelay_us);
+		rtrsp->rt_delay_us = shortdelay_us;
+	}
+	if (!preempt_count() &&
+	    !(torture_random(rrsp) % (nrealreaders * 500))) {
+		torture_preempt_schedule();  /* QS only if preemptible. */
+		rtrsp->rt_preempted = true;
+	}
+}
+
+static void rcu_torture_read_unlock(int idx) __releases(RCU)
+{
+	rcu_read_unlock();
+}
+
+/*
+ * Update callback in the pipe.  This should be invoked after a grace period.
+ */
+static bool
+rcu_torture_pipe_update_one(struct rcu_torture *rp)
+{
+	int i;
+	struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp);
+
+	if (rtrcp) {
+		WRITE_ONCE(rp->rtort_chkp, NULL);
+		smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire().
+	}
+	i = READ_ONCE(rp->rtort_pipe_count);
+	if (i > RCU_TORTURE_PIPE_LEN)
+		i = RCU_TORTURE_PIPE_LEN;
+	atomic_inc(&rcu_torture_wcount[i]);
+	WRITE_ONCE(rp->rtort_pipe_count, i + 1);
+	if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
+		rp->rtort_mbtest = 0;
+		return true;
+	}
+	return false;
+}
+
+/*
+ * Update all callbacks in the pipe.  Suitable for synchronous grace-period
+ * primitives.
+ */
+static void
+rcu_torture_pipe_update(struct rcu_torture *old_rp)
+{
+	struct rcu_torture *rp;
+	struct rcu_torture *rp1;
+
+	if (old_rp)
+		list_add(&old_rp->rtort_free, &rcu_torture_removed);
+	list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
+		if (rcu_torture_pipe_update_one(rp)) {
+			list_del(&rp->rtort_free);
+			rcu_torture_free(rp);
+		}
+	}
+}
+
+static void
+rcu_torture_cb(struct rcu_head *p)
+{
+	struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
+
+	if (torture_must_stop_irq()) {
+		/* Test is ending, just drop callbacks on the floor. */
+		/* The next initialization will pick up the pieces. */
+		return;
+	}
+	if (rcu_torture_pipe_update_one(rp))
+		rcu_torture_free(rp);
+	else
+		cur_ops->deferred_free(rp);
+}
+
+static unsigned long rcu_no_completed(void)
+{
+	return 0;
+}
+
+static void rcu_torture_deferred_free(struct rcu_torture *p)
+{
+	call_rcu(&p->rtort_rcu, rcu_torture_cb);
+}
+
+static void rcu_sync_torture_init(void)
+{
+	INIT_LIST_HEAD(&rcu_torture_removed);
+}
+
+static bool rcu_poll_need_2gp(bool poll, bool poll_full)
+{
+	return poll;
+}
+
+static struct rcu_torture_ops rcu_ops = {
+	.ttype			= RCU_FLAVOR,
+	.init			= rcu_sync_torture_init,
+	.readlock		= rcu_torture_read_lock,
+	.read_delay		= rcu_read_delay,
+	.readunlock		= rcu_torture_read_unlock,
+	.readlock_held		= torture_readlock_not_held,
+	.get_gp_seq		= rcu_get_gp_seq,
+	.gp_diff		= rcu_seq_diff,
+	.deferred_free		= rcu_torture_deferred_free,
+	.sync			= synchronize_rcu,
+	.exp_sync		= synchronize_rcu_expedited,
+	.get_gp_state		= get_state_synchronize_rcu,
+	.get_gp_state_full	= get_state_synchronize_rcu_full,
+	.get_gp_completed	= get_completed_synchronize_rcu,
+	.get_gp_completed_full	= get_completed_synchronize_rcu_full,
+	.start_gp_poll		= start_poll_synchronize_rcu,
+	.start_gp_poll_full	= start_poll_synchronize_rcu_full,
+	.poll_gp_state		= poll_state_synchronize_rcu,
+	.poll_gp_state_full	= poll_state_synchronize_rcu_full,
+	.poll_need_2gp		= rcu_poll_need_2gp,
+	.cond_sync		= cond_synchronize_rcu,
+	.cond_sync_full		= cond_synchronize_rcu_full,
+	.get_gp_state_exp	= get_state_synchronize_rcu,
+	.start_gp_poll_exp	= start_poll_synchronize_rcu_expedited,
+	.start_gp_poll_exp_full	= start_poll_synchronize_rcu_expedited_full,
+	.poll_gp_state_exp	= poll_state_synchronize_rcu,
+	.cond_sync_exp		= cond_synchronize_rcu_expedited,
+	.call			= call_rcu,
+	.cb_barrier		= rcu_barrier,
+	.fqs			= rcu_force_quiescent_state,
+	.stats			= NULL,
+	.gp_kthread_dbg		= show_rcu_gp_kthreads,
+	.check_boost_failed	= rcu_check_boost_fail,
+	.stall_dur		= rcu_jiffies_till_stall_check,
+	.irq_capable		= 1,
+	.can_boost		= IS_ENABLED(CONFIG_RCU_BOOST),
+	.extendables		= RCUTORTURE_MAX_EXTEND,
+	.name			= "rcu"
+};
+
+/*
+ * Don't even think about trying any of these in real life!!!
+ * The names includes "busted", and they really means it!
+ * The only purpose of these functions is to provide a buggy RCU
+ * implementation to make sure that rcutorture correctly emits
+ * buggy-RCU error messages.
+ */
+static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
+{
+	/* This is a deliberate bug for testing purposes only! */
+	rcu_torture_cb(&p->rtort_rcu);
+}
+
+static void synchronize_rcu_busted(void)
+{
+	/* This is a deliberate bug for testing purposes only! */
+}
+
+static void
+call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
+{
+	/* This is a deliberate bug for testing purposes only! */
+	func(head);
+}
+
+static struct rcu_torture_ops rcu_busted_ops = {
+	.ttype		= INVALID_RCU_FLAVOR,
+	.init		= rcu_sync_torture_init,
+	.readlock	= rcu_torture_read_lock,
+	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
+	.readunlock	= rcu_torture_read_unlock,
+	.readlock_held	= torture_readlock_not_held,
+	.get_gp_seq	= rcu_no_completed,
+	.deferred_free	= rcu_busted_torture_deferred_free,
+	.sync		= synchronize_rcu_busted,
+	.exp_sync	= synchronize_rcu_busted,
+	.call		= call_rcu_busted,
+	.cb_barrier	= NULL,
+	.fqs		= NULL,
+	.stats		= NULL,
+	.irq_capable	= 1,
+	.name		= "busted"
+};
+
+/*
+ * Definitions for srcu torture testing.
+ */
+
+DEFINE_STATIC_SRCU(srcu_ctl);
+static struct srcu_struct srcu_ctld;
+static struct srcu_struct *srcu_ctlp = &srcu_ctl;
+
+static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
+{
+	return srcu_read_lock(srcu_ctlp);
+}
+
+static void
+srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
+{
+	long delay;
+	const long uspertick = 1000000 / HZ;
+	const long longdelay = 10;
+
+	/* We want there to be long-running readers, but not all the time. */
+
+	delay = torture_random(rrsp) %
+		(nrealreaders * 2 * longdelay * uspertick);
+	if (!delay && in_task()) {
+		schedule_timeout_interruptible(longdelay);
+		rtrsp->rt_delay_jiffies = longdelay;
+	} else {
+		rcu_read_delay(rrsp, rtrsp);
+	}
+}
+
+static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
+{
+	srcu_read_unlock(srcu_ctlp, idx);
+}
+
+static int torture_srcu_read_lock_held(void)
+{
+	return srcu_read_lock_held(srcu_ctlp);
+}
+
+static unsigned long srcu_torture_completed(void)
+{
+	return srcu_batches_completed(srcu_ctlp);
+}
+
+static void srcu_torture_deferred_free(struct rcu_torture *rp)
+{
+	call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
+}
+
+static void srcu_torture_synchronize(void)
+{
+	synchronize_srcu(srcu_ctlp);
+}
+
+static unsigned long srcu_torture_get_gp_state(void)
+{
+	return get_state_synchronize_srcu(srcu_ctlp);
+}
+
+static unsigned long srcu_torture_start_gp_poll(void)
+{
+	return start_poll_synchronize_srcu(srcu_ctlp);
+}
+
+static bool srcu_torture_poll_gp_state(unsigned long oldstate)
+{
+	return poll_state_synchronize_srcu(srcu_ctlp, oldstate);
+}
+
+static void srcu_torture_call(struct rcu_head *head,
+			      rcu_callback_t func)
+{
+	call_srcu(srcu_ctlp, head, func);
+}
+
+static void srcu_torture_barrier(void)
+{
+	srcu_barrier(srcu_ctlp);
+}
+
+static void srcu_torture_stats(void)
+{
+	srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
+}
+
+static void srcu_torture_synchronize_expedited(void)
+{
+	synchronize_srcu_expedited(srcu_ctlp);
+}
+
+static struct rcu_torture_ops srcu_ops = {
+	.ttype		= SRCU_FLAVOR,
+	.init		= rcu_sync_torture_init,
+	.readlock	= srcu_torture_read_lock,
+	.read_delay	= srcu_read_delay,
+	.readunlock	= srcu_torture_read_unlock,
+	.readlock_held	= torture_srcu_read_lock_held,
+	.get_gp_seq	= srcu_torture_completed,
+	.deferred_free	= srcu_torture_deferred_free,
+	.sync		= srcu_torture_synchronize,
+	.exp_sync	= srcu_torture_synchronize_expedited,
+	.get_gp_state	= srcu_torture_get_gp_state,
+	.start_gp_poll	= srcu_torture_start_gp_poll,
+	.poll_gp_state	= srcu_torture_poll_gp_state,
+	.call		= srcu_torture_call,
+	.cb_barrier	= srcu_torture_barrier,
+	.stats		= srcu_torture_stats,
+	.cbflood_max	= 50000,
+	.irq_capable	= 1,
+	.no_pi_lock	= IS_ENABLED(CONFIG_TINY_SRCU),
+	.name		= "srcu"
+};
+
+static void srcu_torture_init(void)
+{
+	rcu_sync_torture_init();
+	WARN_ON(init_srcu_struct(&srcu_ctld));
+	srcu_ctlp = &srcu_ctld;
+}
+
+static void srcu_torture_cleanup(void)
+{
+	cleanup_srcu_struct(&srcu_ctld);
+	srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
+}
+
+/* As above, but dynamically allocated. */
+static struct rcu_torture_ops srcud_ops = {
+	.ttype		= SRCU_FLAVOR,
+	.init		= srcu_torture_init,
+	.cleanup	= srcu_torture_cleanup,
+	.readlock	= srcu_torture_read_lock,
+	.read_delay	= srcu_read_delay,
+	.readunlock	= srcu_torture_read_unlock,
+	.readlock_held	= torture_srcu_read_lock_held,
+	.get_gp_seq	= srcu_torture_completed,
+	.deferred_free	= srcu_torture_deferred_free,
+	.sync		= srcu_torture_synchronize,
+	.exp_sync	= srcu_torture_synchronize_expedited,
+	.get_gp_state	= srcu_torture_get_gp_state,
+	.start_gp_poll	= srcu_torture_start_gp_poll,
+	.poll_gp_state	= srcu_torture_poll_gp_state,
+	.call		= srcu_torture_call,
+	.cb_barrier	= srcu_torture_barrier,
+	.stats		= srcu_torture_stats,
+	.cbflood_max	= 50000,
+	.irq_capable	= 1,
+	.no_pi_lock	= IS_ENABLED(CONFIG_TINY_SRCU),
+	.name		= "srcud"
+};
+
+/* As above, but broken due to inappropriate reader extension. */
+static struct rcu_torture_ops busted_srcud_ops = {
+	.ttype		= SRCU_FLAVOR,
+	.init		= srcu_torture_init,
+	.cleanup	= srcu_torture_cleanup,
+	.readlock	= srcu_torture_read_lock,
+	.read_delay	= rcu_read_delay,
+	.readunlock	= srcu_torture_read_unlock,
+	.readlock_held	= torture_srcu_read_lock_held,
+	.get_gp_seq	= srcu_torture_completed,
+	.deferred_free	= srcu_torture_deferred_free,
+	.sync		= srcu_torture_synchronize,
+	.exp_sync	= srcu_torture_synchronize_expedited,
+	.call		= srcu_torture_call,
+	.cb_barrier	= srcu_torture_barrier,
+	.stats		= srcu_torture_stats,
+	.irq_capable	= 1,
+	.no_pi_lock	= IS_ENABLED(CONFIG_TINY_SRCU),
+	.extendables	= RCUTORTURE_MAX_EXTEND,
+	.name		= "busted_srcud"
+};
+
+/*
+ * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
+ * This implementation does not necessarily work well with CPU hotplug.
+ */
+
+static void synchronize_rcu_trivial(void)
+{
+	int cpu;
+
+	for_each_online_cpu(cpu) {
+		rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu));
+		WARN_ON_ONCE(raw_smp_processor_id() != cpu);
+	}
+}
+
+static int rcu_torture_read_lock_trivial(void) __acquires(RCU)
+{
+	preempt_disable();
+	return 0;
+}
+
+static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU)
+{
+	preempt_enable();
+}
+
+static struct rcu_torture_ops trivial_ops = {
+	.ttype		= RCU_TRIVIAL_FLAVOR,
+	.init		= rcu_sync_torture_init,
+	.readlock	= rcu_torture_read_lock_trivial,
+	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
+	.readunlock	= rcu_torture_read_unlock_trivial,
+	.readlock_held	= torture_readlock_not_held,
+	.get_gp_seq	= rcu_no_completed,
+	.sync		= synchronize_rcu_trivial,
+	.exp_sync	= synchronize_rcu_trivial,
+	.fqs		= NULL,
+	.stats		= NULL,
+	.irq_capable	= 1,
+	.name		= "trivial"
+};
+
+#ifdef CONFIG_TASKS_RCU
+
+/*
+ * Definitions for RCU-tasks torture testing.
+ */
+
+static int tasks_torture_read_lock(void)
+{
+	return 0;
+}
+
+static void tasks_torture_read_unlock(int idx)
+{
+}
+
+static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
+{
+	call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
+}
+
+static void synchronize_rcu_mult_test(void)
+{
+	synchronize_rcu_mult(call_rcu_tasks, call_rcu);
+}
+
+static struct rcu_torture_ops tasks_ops = {
+	.ttype		= RCU_TASKS_FLAVOR,
+	.init		= rcu_sync_torture_init,
+	.readlock	= tasks_torture_read_lock,
+	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
+	.readunlock	= tasks_torture_read_unlock,
+	.get_gp_seq	= rcu_no_completed,
+	.deferred_free	= rcu_tasks_torture_deferred_free,
+	.sync		= synchronize_rcu_tasks,
+	.exp_sync	= synchronize_rcu_mult_test,
+	.call		= call_rcu_tasks,
+	.cb_barrier	= rcu_barrier_tasks,
+	.gp_kthread_dbg	= show_rcu_tasks_classic_gp_kthread,
+	.fqs		= NULL,
+	.stats		= NULL,
+	.irq_capable	= 1,
+	.slow_gps	= 1,
+	.name		= "tasks"
+};
+
+#define TASKS_OPS &tasks_ops,
+
+#else // #ifdef CONFIG_TASKS_RCU
+
+#define TASKS_OPS
+
+#endif // #else #ifdef CONFIG_TASKS_RCU
+
+
+#ifdef CONFIG_TASKS_RUDE_RCU
+
+/*
+ * Definitions for rude RCU-tasks torture testing.
+ */
+
+static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p)
+{
+	call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb);
+}
+
+static struct rcu_torture_ops tasks_rude_ops = {
+	.ttype		= RCU_TASKS_RUDE_FLAVOR,
+	.init		= rcu_sync_torture_init,
+	.readlock	= rcu_torture_read_lock_trivial,
+	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
+	.readunlock	= rcu_torture_read_unlock_trivial,
+	.get_gp_seq	= rcu_no_completed,
+	.deferred_free	= rcu_tasks_rude_torture_deferred_free,
+	.sync		= synchronize_rcu_tasks_rude,
+	.exp_sync	= synchronize_rcu_tasks_rude,
+	.call		= call_rcu_tasks_rude,
+	.cb_barrier	= rcu_barrier_tasks_rude,
+	.gp_kthread_dbg	= show_rcu_tasks_rude_gp_kthread,
+	.cbflood_max	= 50000,
+	.fqs		= NULL,
+	.stats		= NULL,
+	.irq_capable	= 1,
+	.name		= "tasks-rude"
+};
+
+#define TASKS_RUDE_OPS &tasks_rude_ops,
+
+#else // #ifdef CONFIG_TASKS_RUDE_RCU
+
+#define TASKS_RUDE_OPS
+
+#endif // #else #ifdef CONFIG_TASKS_RUDE_RCU
+
+
+#ifdef CONFIG_TASKS_TRACE_RCU
+
+/*
+ * Definitions for tracing RCU-tasks torture testing.
+ */
+
+static int tasks_tracing_torture_read_lock(void)
+{
+	rcu_read_lock_trace();
+	return 0;
+}
+
+static void tasks_tracing_torture_read_unlock(int idx)
+{
+	rcu_read_unlock_trace();
+}
+
+static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p)
+{
+	call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb);
+}
+
+static struct rcu_torture_ops tasks_tracing_ops = {
+	.ttype		= RCU_TASKS_TRACING_FLAVOR,
+	.init		= rcu_sync_torture_init,
+	.readlock	= tasks_tracing_torture_read_lock,
+	.read_delay	= srcu_read_delay,  /* just reuse srcu's version. */
+	.readunlock	= tasks_tracing_torture_read_unlock,
+	.readlock_held	= rcu_read_lock_trace_held,
+	.get_gp_seq	= rcu_no_completed,
+	.deferred_free	= rcu_tasks_tracing_torture_deferred_free,
+	.sync		= synchronize_rcu_tasks_trace,
+	.exp_sync	= synchronize_rcu_tasks_trace,
+	.call		= call_rcu_tasks_trace,
+	.cb_barrier	= rcu_barrier_tasks_trace,
+	.gp_kthread_dbg	= show_rcu_tasks_trace_gp_kthread,
+	.cbflood_max	= 50000,
+	.fqs		= NULL,
+	.stats		= NULL,
+	.irq_capable	= 1,
+	.slow_gps	= 1,
+	.name		= "tasks-tracing"
+};
+
+#define TASKS_TRACING_OPS &tasks_tracing_ops,
+
+#else // #ifdef CONFIG_TASKS_TRACE_RCU
+
+#define TASKS_TRACING_OPS
+
+#endif // #else #ifdef CONFIG_TASKS_TRACE_RCU
+
+
+static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
+{
+	if (!cur_ops->gp_diff)
+		return new - old;
+	return cur_ops->gp_diff(new, old);
+}
+
+/*
+ * RCU torture priority-boost testing.  Runs one real-time thread per
+ * CPU for moderate bursts, repeatedly starting grace periods and waiting
+ * for them to complete.  If a given grace period takes too long, we assume
+ * that priority inversion has occurred.
+ */
+
+static int old_rt_runtime = -1;
+
+static void rcu_torture_disable_rt_throttle(void)
+{
+	/*
+	 * Disable RT throttling so that rcutorture's boost threads don't get
+	 * throttled. Only possible if rcutorture is built-in otherwise the
+	 * user should manually do this by setting the sched_rt_period_us and
+	 * sched_rt_runtime sysctls.
+	 */
+	if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
+		return;
+
+	old_rt_runtime = sysctl_sched_rt_runtime;
+	sysctl_sched_rt_runtime = -1;
+}
+
+static void rcu_torture_enable_rt_throttle(void)
+{
+	if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
+		return;
+
+	sysctl_sched_rt_runtime = old_rt_runtime;
+	old_rt_runtime = -1;
+}
+
+static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start)
+{
+	int cpu;
+	static int dbg_done;
+	unsigned long end = jiffies;
+	bool gp_done;
+	unsigned long j;
+	static unsigned long last_persist;
+	unsigned long lp;
+	unsigned long mininterval = test_boost_duration * HZ - HZ / 2;
+
+	if (end - *start > mininterval) {
+		// Recheck after checking time to avoid false positives.
+		smp_mb(); // Time check before grace-period check.
+		if (cur_ops->poll_gp_state(gp_state))
+			return false; // passed, though perhaps just barely
+		if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) {
+			// At most one persisted message per boost test.
+			j = jiffies;
+			lp = READ_ONCE(last_persist);
+			if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp)
+				pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu);
+			return false; // passed on a technicality
+		}
+		VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
+		n_rcu_torture_boost_failure++;
+		if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) {
+			pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n",
+				current->rt_priority, gp_state, end - *start);
+			cur_ops->gp_kthread_dbg();
+			// Recheck after print to flag grace period ending during splat.
+			gp_done = cur_ops->poll_gp_state(gp_state);
+			pr_info("Boost inversion: GP %lu %s.\n", gp_state,
+				gp_done ? "ended already" : "still pending");
+
+		}
+
+		return true; // failed
+	} else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) {
+		*start = jiffies;
+	}
+
+	return false; // passed
+}
+
+static int rcu_torture_boost(void *arg)
+{
+	unsigned long endtime;
+	unsigned long gp_state;
+	unsigned long gp_state_time;
+	unsigned long oldstarttime;
+
+	VERBOSE_TOROUT_STRING("rcu_torture_boost started");
+
+	/* Set real-time priority. */
+	sched_set_fifo_low(current);
+
+	/* Each pass through the following loop does one boost-test cycle. */
+	do {
+		bool failed = false; // Test failed already in this test interval
+		bool gp_initiated = false;
+
+		if (kthread_should_stop())
+			goto checkwait;
+
+		/* Wait for the next test interval. */
+		oldstarttime = READ_ONCE(boost_starttime);
+		while (time_before(jiffies, oldstarttime)) {
+			schedule_timeout_interruptible(oldstarttime - jiffies);
+			if (stutter_wait("rcu_torture_boost"))
+				sched_set_fifo_low(current);
+			if (torture_must_stop())
+				goto checkwait;
+		}
+
+		// Do one boost-test interval.
+		endtime = oldstarttime + test_boost_duration * HZ;
+		while (time_before(jiffies, endtime)) {
+			// Has current GP gone too long?
+			if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
+				failed = rcu_torture_boost_failed(gp_state, &gp_state_time);
+			// If we don't have a grace period in flight, start one.
+			if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) {
+				gp_state = cur_ops->start_gp_poll();
+				gp_initiated = true;
+				gp_state_time = jiffies;
+			}
+			if (stutter_wait("rcu_torture_boost")) {
+				sched_set_fifo_low(current);
+				// If the grace period already ended,
+				// we don't know when that happened, so
+				// start over.
+				if (cur_ops->poll_gp_state(gp_state))
+					gp_initiated = false;
+			}
+			if (torture_must_stop())
+				goto checkwait;
+		}
+
+		// In case the grace period extended beyond the end of the loop.
+		if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
+			rcu_torture_boost_failed(gp_state, &gp_state_time);
+
+		/*
+		 * Set the start time of the next test interval.
+		 * Yes, this is vulnerable to long delays, but such
+		 * delays simply cause a false negative for the next
+		 * interval.  Besides, we are running at RT priority,
+		 * so delays should be relatively rare.
+		 */
+		while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) {
+			if (mutex_trylock(&boost_mutex)) {
+				if (oldstarttime == boost_starttime) {
+					WRITE_ONCE(boost_starttime,
+						   jiffies + test_boost_interval * HZ);
+					n_rcu_torture_boosts++;
+				}
+				mutex_unlock(&boost_mutex);
+				break;
+			}
+			schedule_timeout_uninterruptible(1);
+		}
+
+		/* Go do the stutter. */
+checkwait:	if (stutter_wait("rcu_torture_boost"))
+			sched_set_fifo_low(current);
+	} while (!torture_must_stop());
+
+	/* Clean up and exit. */
+	while (!kthread_should_stop()) {
+		torture_shutdown_absorb("rcu_torture_boost");
+		schedule_timeout_uninterruptible(1);
+	}
+	torture_kthread_stopping("rcu_torture_boost");
+	return 0;
+}
+
+/*
+ * RCU torture force-quiescent-state kthread.  Repeatedly induces
+ * bursts of calls to force_quiescent_state(), increasing the probability
+ * of occurrence of some important types of race conditions.
+ */
+static int
+rcu_torture_fqs(void *arg)
+{
+	unsigned long fqs_resume_time;
+	int fqs_burst_remaining;
+	int oldnice = task_nice(current);
+
+	VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
+	do {
+		fqs_resume_time = jiffies + fqs_stutter * HZ;
+		while (time_before(jiffies, fqs_resume_time) &&
+		       !kthread_should_stop()) {
+			schedule_timeout_interruptible(1);
+		}
+		fqs_burst_remaining = fqs_duration;
+		while (fqs_burst_remaining > 0 &&
+		       !kthread_should_stop()) {
+			cur_ops->fqs();
+			udelay(fqs_holdoff);
+			fqs_burst_remaining -= fqs_holdoff;
+		}
+		if (stutter_wait("rcu_torture_fqs"))
+			sched_set_normal(current, oldnice);
+	} while (!torture_must_stop());
+	torture_kthread_stopping("rcu_torture_fqs");
+	return 0;
+}
+
+// Used by writers to randomly choose from the available grace-period primitives.
+static int synctype[ARRAY_SIZE(rcu_torture_writer_state_names)] = { };
+static int nsynctypes;
+
+/*
+ * Determine which grace-period primitives are available.
+ */
+static void rcu_torture_write_types(void)
+{
+	bool gp_cond1 = gp_cond, gp_cond_exp1 = gp_cond_exp, gp_cond_full1 = gp_cond_full;
+	bool gp_cond_exp_full1 = gp_cond_exp_full, gp_exp1 = gp_exp, gp_poll_exp1 = gp_poll_exp;
+	bool gp_poll_exp_full1 = gp_poll_exp_full, gp_normal1 = gp_normal, gp_poll1 = gp_poll;
+	bool gp_poll_full1 = gp_poll_full, gp_sync1 = gp_sync;
+
+	/* Initialize synctype[] array.  If none set, take default. */
+	if (!gp_cond1 &&
+	    !gp_cond_exp1 &&
+	    !gp_cond_full1 &&
+	    !gp_cond_exp_full1 &&
+	    !gp_exp1 &&
+	    !gp_poll_exp1 &&
+	    !gp_poll_exp_full1 &&
+	    !gp_normal1 &&
+	    !gp_poll1 &&
+	    !gp_poll_full1 &&
+	    !gp_sync1) {
+		gp_cond1 = true;
+		gp_cond_exp1 = true;
+		gp_cond_full1 = true;
+		gp_cond_exp_full1 = true;
+		gp_exp1 = true;
+		gp_poll_exp1 = true;
+		gp_poll_exp_full1 = true;
+		gp_normal1 = true;
+		gp_poll1 = true;
+		gp_poll_full1 = true;
+		gp_sync1 = true;
+	}
+	if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) {
+		synctype[nsynctypes++] = RTWS_COND_GET;
+		pr_info("%s: Testing conditional GPs.\n", __func__);
+	} else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) {
+		pr_alert("%s: gp_cond without primitives.\n", __func__);
+	}
+	if (gp_cond_exp1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp) {
+		synctype[nsynctypes++] = RTWS_COND_GET_EXP;
+		pr_info("%s: Testing conditional expedited GPs.\n", __func__);
+	} else if (gp_cond_exp && (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp)) {
+		pr_alert("%s: gp_cond_exp without primitives.\n", __func__);
+	}
+	if (gp_cond_full1 && cur_ops->get_gp_state && cur_ops->cond_sync_full) {
+		synctype[nsynctypes++] = RTWS_COND_GET_FULL;
+		pr_info("%s: Testing conditional full-state GPs.\n", __func__);
+	} else if (gp_cond_full && (!cur_ops->get_gp_state || !cur_ops->cond_sync_full)) {
+		pr_alert("%s: gp_cond_full without primitives.\n", __func__);
+	}
+	if (gp_cond_exp_full1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp_full) {
+		synctype[nsynctypes++] = RTWS_COND_GET_EXP_FULL;
+		pr_info("%s: Testing conditional full-state expedited GPs.\n", __func__);
+	} else if (gp_cond_exp_full &&
+		   (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp_full)) {
+		pr_alert("%s: gp_cond_exp_full without primitives.\n", __func__);
+	}
+	if (gp_exp1 && cur_ops->exp_sync) {
+		synctype[nsynctypes++] = RTWS_EXP_SYNC;
+		pr_info("%s: Testing expedited GPs.\n", __func__);
+	} else if (gp_exp && !cur_ops->exp_sync) {
+		pr_alert("%s: gp_exp without primitives.\n", __func__);
+	}
+	if (gp_normal1 && cur_ops->deferred_free) {
+		synctype[nsynctypes++] = RTWS_DEF_FREE;
+		pr_info("%s: Testing asynchronous GPs.\n", __func__);
+	} else if (gp_normal && !cur_ops->deferred_free) {
+		pr_alert("%s: gp_normal without primitives.\n", __func__);
+	}
+	if (gp_poll1 && cur_ops->start_gp_poll && cur_ops->poll_gp_state) {
+		synctype[nsynctypes++] = RTWS_POLL_GET;
+		pr_info("%s: Testing polling GPs.\n", __func__);
+	} else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) {
+		pr_alert("%s: gp_poll without primitives.\n", __func__);
+	}
+	if (gp_poll_full1 && cur_ops->start_gp_poll_full && cur_ops->poll_gp_state_full) {
+		synctype[nsynctypes++] = RTWS_POLL_GET_FULL;
+		pr_info("%s: Testing polling full-state GPs.\n", __func__);
+	} else if (gp_poll_full && (!cur_ops->start_gp_poll_full || !cur_ops->poll_gp_state_full)) {
+		pr_alert("%s: gp_poll_full without primitives.\n", __func__);
+	}
+	if (gp_poll_exp1 && cur_ops->start_gp_poll_exp && cur_ops->poll_gp_state_exp) {
+		synctype[nsynctypes++] = RTWS_POLL_GET_EXP;
+		pr_info("%s: Testing polling expedited GPs.\n", __func__);
+	} else if (gp_poll_exp && (!cur_ops->start_gp_poll_exp || !cur_ops->poll_gp_state_exp)) {
+		pr_alert("%s: gp_poll_exp without primitives.\n", __func__);
+	}
+	if (gp_poll_exp_full1 && cur_ops->start_gp_poll_exp_full && cur_ops->poll_gp_state_full) {
+		synctype[nsynctypes++] = RTWS_POLL_GET_EXP_FULL;
+		pr_info("%s: Testing polling full-state expedited GPs.\n", __func__);
+	} else if (gp_poll_exp_full &&
+		   (!cur_ops->start_gp_poll_exp_full || !cur_ops->poll_gp_state_full)) {
+		pr_alert("%s: gp_poll_exp_full without primitives.\n", __func__);
+	}
+	if (gp_sync1 && cur_ops->sync) {
+		synctype[nsynctypes++] = RTWS_SYNC;
+		pr_info("%s: Testing normal GPs.\n", __func__);
+	} else if (gp_sync && !cur_ops->sync) {
+		pr_alert("%s: gp_sync without primitives.\n", __func__);
+	}
+}
+
+/*
+ * Do the specified rcu_torture_writer() synchronous grace period,
+ * while also testing out the polled APIs.  Note well that the single-CPU
+ * grace-period optimizations must be accounted for.
+ */
+static void do_rtws_sync(struct torture_random_state *trsp, void (*sync)(void))
+{
+	unsigned long cookie;
+	struct rcu_gp_oldstate cookie_full;
+	bool dopoll;
+	bool dopoll_full;
+	unsigned long r = torture_random(trsp);
+
+	dopoll = cur_ops->get_gp_state && cur_ops->poll_gp_state && !(r & 0x300);
+	dopoll_full = cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full && !(r & 0xc00);
+	if (dopoll || dopoll_full)
+		cpus_read_lock();
+	if (dopoll)
+		cookie = cur_ops->get_gp_state();
+	if (dopoll_full)
+		cur_ops->get_gp_state_full(&cookie_full);
+	if (cur_ops->poll_need_2gp && cur_ops->poll_need_2gp(dopoll, dopoll_full))
+		sync();
+	sync();
+	WARN_ONCE(dopoll && !cur_ops->poll_gp_state(cookie),
+		  "%s: Cookie check 3 failed %pS() online %*pbl.",
+		  __func__, sync, cpumask_pr_args(cpu_online_mask));
+	WARN_ONCE(dopoll_full && !cur_ops->poll_gp_state_full(&cookie_full),
+		  "%s: Cookie check 4 failed %pS() online %*pbl",
+		  __func__, sync, cpumask_pr_args(cpu_online_mask));
+	if (dopoll || dopoll_full)
+		cpus_read_unlock();
+}
+
+/*
+ * RCU torture writer kthread.  Repeatedly substitutes a new structure
+ * for that pointed to by rcu_torture_current, freeing the old structure
+ * after a series of grace periods (the "pipeline").
+ */
+static int
+rcu_torture_writer(void *arg)
+{
+	bool boot_ended;
+	bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
+	unsigned long cookie;
+	struct rcu_gp_oldstate cookie_full;
+	int expediting = 0;
+	unsigned long gp_snap;
+	struct rcu_gp_oldstate gp_snap_full;
+	int i;
+	int idx;
+	int oldnice = task_nice(current);
+	struct rcu_torture *rp;
+	struct rcu_torture *old_rp;
+	static DEFINE_TORTURE_RANDOM(rand);
+	bool stutter_waited;
+
+	VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
+	if (!can_expedite)
+		pr_alert("%s" TORTURE_FLAG
+			 " GP expediting controlled from boot/sysfs for %s.\n",
+			 torture_type, cur_ops->name);
+	if (WARN_ONCE(nsynctypes == 0,
+		      "%s: No update-side primitives.\n", __func__)) {
+		/*
+		 * No updates primitives, so don't try updating.
+		 * The resulting test won't be testing much, hence the
+		 * above WARN_ONCE().
+		 */
+		rcu_torture_writer_state = RTWS_STOPPING;
+		torture_kthread_stopping("rcu_torture_writer");
+		return 0;
+	}
+
+	do {
+		rcu_torture_writer_state = RTWS_FIXED_DELAY;
+		torture_hrtimeout_us(500, 1000, &rand);
+		rp = rcu_torture_alloc();
+		if (rp == NULL)
+			continue;
+		rp->rtort_pipe_count = 0;
+		rcu_torture_writer_state = RTWS_DELAY;
+		udelay(torture_random(&rand) & 0x3ff);
+		rcu_torture_writer_state = RTWS_REPLACE;
+		old_rp = rcu_dereference_check(rcu_torture_current,
+					       current == writer_task);
+		rp->rtort_mbtest = 1;
+		rcu_assign_pointer(rcu_torture_current, rp);
+		smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
+		if (old_rp) {
+			i = old_rp->rtort_pipe_count;
+			if (i > RCU_TORTURE_PIPE_LEN)
+				i = RCU_TORTURE_PIPE_LEN;
+			atomic_inc(&rcu_torture_wcount[i]);
+			WRITE_ONCE(old_rp->rtort_pipe_count,
+				   old_rp->rtort_pipe_count + 1);
+
+			// Make sure readers block polled grace periods.
+			if (cur_ops->get_gp_state && cur_ops->poll_gp_state) {
+				idx = cur_ops->readlock();
+				cookie = cur_ops->get_gp_state();
+				WARN_ONCE(cur_ops->poll_gp_state(cookie),
+					  "%s: Cookie check 1 failed %s(%d) %lu->%lu\n",
+					  __func__,
+					  rcu_torture_writer_state_getname(),
+					  rcu_torture_writer_state,
+					  cookie, cur_ops->get_gp_state());
+				if (cur_ops->get_gp_completed) {
+					cookie = cur_ops->get_gp_completed();
+					WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie));
+				}
+				cur_ops->readunlock(idx);
+			}
+			if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) {
+				idx = cur_ops->readlock();
+				cur_ops->get_gp_state_full(&cookie_full);
+				WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
+					  "%s: Cookie check 5 failed %s(%d) online %*pbl\n",
+					  __func__,
+					  rcu_torture_writer_state_getname(),
+					  rcu_torture_writer_state,
+					  cpumask_pr_args(cpu_online_mask));
+				if (cur_ops->get_gp_completed_full) {
+					cur_ops->get_gp_completed_full(&cookie_full);
+					WARN_ON_ONCE(!cur_ops->poll_gp_state_full(&cookie_full));
+				}
+				cur_ops->readunlock(idx);
+			}
+			switch (synctype[torture_random(&rand) % nsynctypes]) {
+			case RTWS_DEF_FREE:
+				rcu_torture_writer_state = RTWS_DEF_FREE;
+				cur_ops->deferred_free(old_rp);
+				break;
+			case RTWS_EXP_SYNC:
+				rcu_torture_writer_state = RTWS_EXP_SYNC;
+				do_rtws_sync(&rand, cur_ops->exp_sync);
+				rcu_torture_pipe_update(old_rp);
+				break;
+			case RTWS_COND_GET:
+				rcu_torture_writer_state = RTWS_COND_GET;
+				gp_snap = cur_ops->get_gp_state();
+				torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
+				rcu_torture_writer_state = RTWS_COND_SYNC;
+				cur_ops->cond_sync(gp_snap);
+				rcu_torture_pipe_update(old_rp);
+				break;
+			case RTWS_COND_GET_EXP:
+				rcu_torture_writer_state = RTWS_COND_GET_EXP;
+				gp_snap = cur_ops->get_gp_state_exp();
+				torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
+				rcu_torture_writer_state = RTWS_COND_SYNC_EXP;
+				cur_ops->cond_sync_exp(gp_snap);
+				rcu_torture_pipe_update(old_rp);
+				break;
+			case RTWS_COND_GET_FULL:
+				rcu_torture_writer_state = RTWS_COND_GET_FULL;
+				cur_ops->get_gp_state_full(&gp_snap_full);
+				torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
+				rcu_torture_writer_state = RTWS_COND_SYNC_FULL;
+				cur_ops->cond_sync_full(&gp_snap_full);
+				rcu_torture_pipe_update(old_rp);
+				break;
+			case RTWS_COND_GET_EXP_FULL:
+				rcu_torture_writer_state = RTWS_COND_GET_EXP_FULL;
+				cur_ops->get_gp_state_full(&gp_snap_full);
+				torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
+				rcu_torture_writer_state = RTWS_COND_SYNC_EXP_FULL;
+				cur_ops->cond_sync_exp_full(&gp_snap_full);
+				rcu_torture_pipe_update(old_rp);
+				break;
+			case RTWS_POLL_GET:
+				rcu_torture_writer_state = RTWS_POLL_GET;
+				gp_snap = cur_ops->start_gp_poll();
+				rcu_torture_writer_state = RTWS_POLL_WAIT;
+				while (!cur_ops->poll_gp_state(gp_snap))
+					torture_hrtimeout_jiffies(torture_random(&rand) % 16,
+								  &rand);
+				rcu_torture_pipe_update(old_rp);
+				break;
+			case RTWS_POLL_GET_FULL:
+				rcu_torture_writer_state = RTWS_POLL_GET_FULL;
+				cur_ops->start_gp_poll_full(&gp_snap_full);
+				rcu_torture_writer_state = RTWS_POLL_WAIT_FULL;
+				while (!cur_ops->poll_gp_state_full(&gp_snap_full))
+					torture_hrtimeout_jiffies(torture_random(&rand) % 16,
+								  &rand);
+				rcu_torture_pipe_update(old_rp);
+				break;
+			case RTWS_POLL_GET_EXP:
+				rcu_torture_writer_state = RTWS_POLL_GET_EXP;
+				gp_snap = cur_ops->start_gp_poll_exp();
+				rcu_torture_writer_state = RTWS_POLL_WAIT_EXP;
+				while (!cur_ops->poll_gp_state_exp(gp_snap))
+					torture_hrtimeout_jiffies(torture_random(&rand) % 16,
+								  &rand);
+				rcu_torture_pipe_update(old_rp);
+				break;
+			case RTWS_POLL_GET_EXP_FULL:
+				rcu_torture_writer_state = RTWS_POLL_GET_EXP_FULL;
+				cur_ops->start_gp_poll_exp_full(&gp_snap_full);
+				rcu_torture_writer_state = RTWS_POLL_WAIT_EXP_FULL;
+				while (!cur_ops->poll_gp_state_full(&gp_snap_full))
+					torture_hrtimeout_jiffies(torture_random(&rand) % 16,
+								  &rand);
+				rcu_torture_pipe_update(old_rp);
+				break;
+			case RTWS_SYNC:
+				rcu_torture_writer_state = RTWS_SYNC;
+				do_rtws_sync(&rand, cur_ops->sync);
+				rcu_torture_pipe_update(old_rp);
+				break;
+			default:
+				WARN_ON_ONCE(1);
+				break;
+			}
+		}
+		WRITE_ONCE(rcu_torture_current_version,
+			   rcu_torture_current_version + 1);
+		/* Cycle through nesting levels of rcu_expedite_gp() calls. */
+		if (can_expedite &&
+		    !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
+			WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
+			if (expediting >= 0)
+				rcu_expedite_gp();
+			else
+				rcu_unexpedite_gp();
+			if (++expediting > 3)
+				expediting = -expediting;
+		} else if (!can_expedite) { /* Disabled during boot, recheck. */
+			can_expedite = !rcu_gp_is_expedited() &&
+				       !rcu_gp_is_normal();
+		}
+		rcu_torture_writer_state = RTWS_STUTTER;
+		boot_ended = rcu_inkernel_boot_has_ended();
+		stutter_waited = stutter_wait("rcu_torture_writer");
+		if (stutter_waited &&
+		    !atomic_read(&rcu_fwd_cb_nodelay) &&
+		    !cur_ops->slow_gps &&
+		    !torture_must_stop() &&
+		    boot_ended)
+			for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
+				if (list_empty(&rcu_tortures[i].rtort_free) &&
+				    rcu_access_pointer(rcu_torture_current) !=
+				    &rcu_tortures[i]) {
+					tracing_off();
+					WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
+					rcu_ftrace_dump(DUMP_ALL);
+				}
+		if (stutter_waited)
+			sched_set_normal(current, oldnice);
+	} while (!torture_must_stop());
+	rcu_torture_current = NULL;  // Let stats task know that we are done.
+	/* Reset expediting back to unexpedited. */
+	if (expediting > 0)
+		expediting = -expediting;
+	while (can_expedite && expediting++ < 0)
+		rcu_unexpedite_gp();
+	WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
+	if (!can_expedite)
+		pr_alert("%s" TORTURE_FLAG
+			 " Dynamic grace-period expediting was disabled.\n",
+			 torture_type);
+	rcu_torture_writer_state = RTWS_STOPPING;
+	torture_kthread_stopping("rcu_torture_writer");
+	return 0;
+}
+
+/*
+ * RCU torture fake writer kthread.  Repeatedly calls sync, with a random
+ * delay between calls.
+ */
+static int
+rcu_torture_fakewriter(void *arg)
+{
+	unsigned long gp_snap;
+	struct rcu_gp_oldstate gp_snap_full;
+	DEFINE_TORTURE_RANDOM(rand);
+
+	VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
+	set_user_nice(current, MAX_NICE);
+
+	if (WARN_ONCE(nsynctypes == 0,
+		      "%s: No update-side primitives.\n", __func__)) {
+		/*
+		 * No updates primitives, so don't try updating.
+		 * The resulting test won't be testing much, hence the
+		 * above WARN_ONCE().
+		 */
+		torture_kthread_stopping("rcu_torture_fakewriter");
+		return 0;
+	}
+
+	do {
+		torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand);
+		if (cur_ops->cb_barrier != NULL &&
+		    torture_random(&rand) % (nfakewriters * 8) == 0) {
+			cur_ops->cb_barrier();
+		} else {
+			switch (synctype[torture_random(&rand) % nsynctypes]) {
+			case RTWS_DEF_FREE:
+				break;
+			case RTWS_EXP_SYNC:
+				cur_ops->exp_sync();
+				break;
+			case RTWS_COND_GET:
+				gp_snap = cur_ops->get_gp_state();
+				torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
+				cur_ops->cond_sync(gp_snap);
+				break;
+			case RTWS_COND_GET_EXP:
+				gp_snap = cur_ops->get_gp_state_exp();
+				torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
+				cur_ops->cond_sync_exp(gp_snap);
+				break;
+			case RTWS_COND_GET_FULL:
+				cur_ops->get_gp_state_full(&gp_snap_full);
+				torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
+				cur_ops->cond_sync_full(&gp_snap_full);
+				break;
+			case RTWS_COND_GET_EXP_FULL:
+				cur_ops->get_gp_state_full(&gp_snap_full);
+				torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
+				cur_ops->cond_sync_exp_full(&gp_snap_full);
+				break;
+			case RTWS_POLL_GET:
+				gp_snap = cur_ops->start_gp_poll();
+				while (!cur_ops->poll_gp_state(gp_snap)) {
+					torture_hrtimeout_jiffies(torture_random(&rand) % 16,
+								  &rand);
+				}
+				break;
+			case RTWS_POLL_GET_FULL:
+				cur_ops->start_gp_poll_full(&gp_snap_full);
+				while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
+					torture_hrtimeout_jiffies(torture_random(&rand) % 16,
+								  &rand);
+				}
+				break;
+			case RTWS_POLL_GET_EXP:
+				gp_snap = cur_ops->start_gp_poll_exp();
+				while (!cur_ops->poll_gp_state_exp(gp_snap)) {
+					torture_hrtimeout_jiffies(torture_random(&rand) % 16,
+								  &rand);
+				}
+				break;
+			case RTWS_POLL_GET_EXP_FULL:
+				cur_ops->start_gp_poll_exp_full(&gp_snap_full);
+				while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
+					torture_hrtimeout_jiffies(torture_random(&rand) % 16,
+								  &rand);
+				}
+				break;
+			case RTWS_SYNC:
+				cur_ops->sync();
+				break;
+			default:
+				WARN_ON_ONCE(1);
+				break;
+			}
+		}
+		stutter_wait("rcu_torture_fakewriter");
+	} while (!torture_must_stop());
+
+	torture_kthread_stopping("rcu_torture_fakewriter");
+	return 0;
+}
+
+static void rcu_torture_timer_cb(struct rcu_head *rhp)
+{
+	kfree(rhp);
+}
+
+// Set up and carry out testing of RCU's global memory ordering
+static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp,
+					struct torture_random_state *trsp)
+{
+	unsigned long loops;
+	int noc = torture_num_online_cpus();
+	int rdrchked;
+	int rdrchker;
+	struct rcu_torture_reader_check *rtrcp; // Me.
+	struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking.
+	struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked.
+	struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me.
+
+	if (myid < 0)
+		return; // Don't try this from timer handlers.
+
+	// Increment my counter.
+	rtrcp = &rcu_torture_reader_mbchk[myid];
+	WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1);
+
+	// Attempt to assign someone else some checking work.
+	rdrchked = torture_random(trsp) % nrealreaders;
+	rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
+	rdrchker = torture_random(trsp) % nrealreaders;
+	rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker];
+	if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker &&
+	    smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below.
+	    !READ_ONCE(rtp->rtort_chkp) &&
+	    !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below.
+		rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops);
+		WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0);
+		rtrcp->rtc_chkrdr = rdrchked;
+		WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends.
+		if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) ||
+		    cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp))
+			(void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out.
+	}
+
+	// If assigned some completed work, do it!
+	rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner);
+	if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready))
+		return; // No work or work not yet ready.
+	rdrchked = rtrcp_assigner->rtc_chkrdr;
+	if (WARN_ON_ONCE(rdrchked < 0))
+		return;
+	rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
+	loops = READ_ONCE(rtrcp_chked->rtc_myloops);
+	atomic_inc(&n_rcu_torture_mbchk_tries);
+	if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops))
+		atomic_inc(&n_rcu_torture_mbchk_fail);
+	rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2;
+	rtrcp_assigner->rtc_ready = 0;
+	smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work.
+	smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign.
+}
+
+/*
+ * Do one extension of an RCU read-side critical section using the
+ * current reader state in readstate (set to zero for initial entry
+ * to extended critical section), set the new state as specified by
+ * newstate (set to zero for final exit from extended critical section),
+ * and random-number-generator state in trsp.  If this is neither the
+ * beginning or end of the critical section and if there was actually a
+ * change, do a ->read_delay().
+ */
+static void rcutorture_one_extend(int *readstate, int newstate,
+				  struct torture_random_state *trsp,
+				  struct rt_read_seg *rtrsp)
+{
+	unsigned long flags;
+	int idxnew1 = -1;
+	int idxnew2 = -1;
+	int idxold1 = *readstate;
+	int idxold2 = idxold1;
+	int statesnew = ~*readstate & newstate;
+	int statesold = *readstate & ~newstate;
+
+	WARN_ON_ONCE(idxold2 < 0);
+	WARN_ON_ONCE((idxold2 >> RCUTORTURE_RDR_SHIFT_2) > 1);
+	rtrsp->rt_readstate = newstate;
+
+	/* First, put new protection in place to avoid critical-section gap. */
+	if (statesnew & RCUTORTURE_RDR_BH)
+		local_bh_disable();
+	if (statesnew & RCUTORTURE_RDR_RBH)
+		rcu_read_lock_bh();
+	if (statesnew & RCUTORTURE_RDR_IRQ)
+		local_irq_disable();
+	if (statesnew & RCUTORTURE_RDR_PREEMPT)
+		preempt_disable();
+	if (statesnew & RCUTORTURE_RDR_SCHED)
+		rcu_read_lock_sched();
+	if (statesnew & RCUTORTURE_RDR_RCU_1)
+		idxnew1 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_1;
+	if (statesnew & RCUTORTURE_RDR_RCU_2)
+		idxnew2 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_2;
+
+	/*
+	 * Next, remove old protection, in decreasing order of strength
+	 * to avoid unlock paths that aren't safe in the stronger
+	 * context. Namely: BH can not be enabled with disabled interrupts.
+	 * Additionally PREEMPT_RT requires that BH is enabled in preemptible
+	 * context.
+	 */
+	if (statesold & RCUTORTURE_RDR_IRQ)
+		local_irq_enable();
+	if (statesold & RCUTORTURE_RDR_PREEMPT)
+		preempt_enable();
+	if (statesold & RCUTORTURE_RDR_SCHED)
+		rcu_read_unlock_sched();
+	if (statesold & RCUTORTURE_RDR_BH)
+		local_bh_enable();
+	if (statesold & RCUTORTURE_RDR_RBH)
+		rcu_read_unlock_bh();
+	if (statesold & RCUTORTURE_RDR_RCU_2) {
+		cur_ops->readunlock((idxold2 >> RCUTORTURE_RDR_SHIFT_2) & 0x1);
+		WARN_ON_ONCE(idxnew2 != -1);
+		idxold2 = 0;
+	}
+	if (statesold & RCUTORTURE_RDR_RCU_1) {
+		bool lockit;
+
+		lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff);
+		if (lockit)
+			raw_spin_lock_irqsave(&current->pi_lock, flags);
+		cur_ops->readunlock((idxold1 >> RCUTORTURE_RDR_SHIFT_1) & 0x1);
+		WARN_ON_ONCE(idxnew1 != -1);
+		idxold1 = 0;
+		if (lockit)
+			raw_spin_unlock_irqrestore(&current->pi_lock, flags);
+	}
+
+	/* Delay if neither beginning nor end and there was a change. */
+	if ((statesnew || statesold) && *readstate && newstate)
+		cur_ops->read_delay(trsp, rtrsp);
+
+	/* Update the reader state. */
+	if (idxnew1 == -1)
+		idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1;
+	WARN_ON_ONCE(idxnew1 < 0);
+	if (WARN_ON_ONCE((idxnew1 >> RCUTORTURE_RDR_SHIFT_1) > 1))
+		pr_info("Unexpected idxnew1 value of %#x\n", idxnew1);
+	if (idxnew2 == -1)
+		idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2;
+	WARN_ON_ONCE(idxnew2 < 0);
+	WARN_ON_ONCE((idxnew2 >> RCUTORTURE_RDR_SHIFT_2) > 1);
+	*readstate = idxnew1 | idxnew2 | newstate;
+	WARN_ON_ONCE(*readstate < 0);
+	if (WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT_2) > 1))
+		pr_info("Unexpected idxnew2 value of %#x\n", idxnew2);
+}
+
+/* Return the biggest extendables mask given current RCU and boot parameters. */
+static int rcutorture_extend_mask_max(void)
+{
+	int mask;
+
+	WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
+	mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
+	mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2;
+	return mask;
+}
+
+/* Return a random protection state mask, but with at least one bit set. */
+static int
+rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
+{
+	int mask = rcutorture_extend_mask_max();
+	unsigned long randmask1 = torture_random(trsp) >> 8;
+	unsigned long randmask2 = randmask1 >> 3;
+	unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
+	unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ;
+	unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
+
+	WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1);
+	/* Mostly only one bit (need preemption!), sometimes lots of bits. */
+	if (!(randmask1 & 0x7))
+		mask = mask & randmask2;
+	else
+		mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
+
+	// Can't have nested RCU reader without outer RCU reader.
+	if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) {
+		if (oldmask & RCUTORTURE_RDR_RCU_1)
+			mask &= ~RCUTORTURE_RDR_RCU_2;
+		else
+			mask |= RCUTORTURE_RDR_RCU_1;
+	}
+
+	/*
+	 * Can't enable bh w/irq disabled.
+	 */
+	if (mask & RCUTORTURE_RDR_IRQ)
+		mask |= oldmask & bhs;
+
+	/*
+	 * Ideally these sequences would be detected in debug builds
+	 * (regardless of RT), but until then don't stop testing
+	 * them on non-RT.
+	 */
+	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+		/* Can't modify BH in atomic context */
+		if (oldmask & preempts_irq)
+			mask &= ~bhs;
+		if ((oldmask | mask) & preempts_irq)
+			mask |= oldmask & bhs;
+	}
+
+	return mask ?: RCUTORTURE_RDR_RCU_1;
+}
+
+/*
+ * Do a randomly selected number of extensions of an existing RCU read-side
+ * critical section.
+ */
+static struct rt_read_seg *
+rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
+		       struct rt_read_seg *rtrsp)
+{
+	int i;
+	int j;
+	int mask = rcutorture_extend_mask_max();
+
+	WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
+	if (!((mask - 1) & mask))
+		return rtrsp;  /* Current RCU reader not extendable. */
+	/* Bias towards larger numbers of loops. */
+	i = (torture_random(trsp) >> 3);
+	i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
+	for (j = 0; j < i; j++) {
+		mask = rcutorture_extend_mask(*readstate, trsp);
+		rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
+	}
+	return &rtrsp[j];
+}
+
+/*
+ * Do one read-side critical section, returning false if there was
+ * no data to read.  Can be invoked both from process context and
+ * from a timer handler.
+ */
+static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
+{
+	bool checkpolling = !(torture_random(trsp) & 0xfff);
+	unsigned long cookie;
+	struct rcu_gp_oldstate cookie_full;
+	int i;
+	unsigned long started;
+	unsigned long completed;
+	int newstate;
+	struct rcu_torture *p;
+	int pipe_count;
+	int readstate = 0;
+	struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } };
+	struct rt_read_seg *rtrsp = &rtseg[0];
+	struct rt_read_seg *rtrsp1;
+	unsigned long long ts;
+
+	WARN_ON_ONCE(!rcu_is_watching());
+	newstate = rcutorture_extend_mask(readstate, trsp);
+	rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
+	if (checkpolling) {
+		if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
+			cookie = cur_ops->get_gp_state();
+		if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
+			cur_ops->get_gp_state_full(&cookie_full);
+	}
+	started = cur_ops->get_gp_seq();
+	ts = rcu_trace_clock_local();
+	p = rcu_dereference_check(rcu_torture_current,
+				  !cur_ops->readlock_held || cur_ops->readlock_held());
+	if (p == NULL) {
+		/* Wait for rcu_torture_writer to get underway */
+		rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
+		return false;
+	}
+	if (p->rtort_mbtest == 0)
+		atomic_inc(&n_rcu_torture_mberror);
+	rcu_torture_reader_do_mbchk(myid, p, trsp);
+	rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp);
+	preempt_disable();
+	pipe_count = READ_ONCE(p->rtort_pipe_count);
+	if (pipe_count > RCU_TORTURE_PIPE_LEN) {
+		/* Should not happen, but... */
+		pipe_count = RCU_TORTURE_PIPE_LEN;
+	}
+	completed = cur_ops->get_gp_seq();
+	if (pipe_count > 1) {
+		do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
+					  ts, started, completed);
+		rcu_ftrace_dump(DUMP_ALL);
+	}
+	__this_cpu_inc(rcu_torture_count[pipe_count]);
+	completed = rcutorture_seq_diff(completed, started);
+	if (completed > RCU_TORTURE_PIPE_LEN) {
+		/* Should not happen, but... */
+		completed = RCU_TORTURE_PIPE_LEN;
+	}
+	__this_cpu_inc(rcu_torture_batch[completed]);
+	preempt_enable();
+	if (checkpolling) {
+		if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
+			WARN_ONCE(cur_ops->poll_gp_state(cookie),
+				  "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
+				  __func__,
+				  rcu_torture_writer_state_getname(),
+				  rcu_torture_writer_state,
+				  cookie, cur_ops->get_gp_state());
+		if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
+			WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
+				  "%s: Cookie check 6 failed %s(%d) online %*pbl\n",
+				  __func__,
+				  rcu_torture_writer_state_getname(),
+				  rcu_torture_writer_state,
+				  cpumask_pr_args(cpu_online_mask));
+	}
+	rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
+	WARN_ON_ONCE(readstate);
+	// This next splat is expected behavior if leakpointer, especially
+	// for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels.
+	WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1);
+
+	/* If error or close call, record the sequence of reader protections. */
+	if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
+		i = 0;
+		for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++)
+			err_segs[i++] = *rtrsp1;
+		rt_read_nsegs = i;
+	}
+
+	return true;
+}
+
+static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
+
+/*
+ * RCU torture reader from timer handler.  Dereferences rcu_torture_current,
+ * incrementing the corresponding element of the pipeline array.  The
+ * counter in the element should never be greater than 1, otherwise, the
+ * RCU implementation is broken.
+ */
+static void rcu_torture_timer(struct timer_list *unused)
+{
+	atomic_long_inc(&n_rcu_torture_timers);
+	(void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1);
+
+	/* Test call_rcu() invocation from interrupt handler. */
+	if (cur_ops->call) {
+		struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
+
+		if (rhp)
+			cur_ops->call(rhp, rcu_torture_timer_cb);
+	}
+}
+
+/*
+ * RCU torture reader kthread.  Repeatedly dereferences rcu_torture_current,
+ * incrementing the corresponding element of the pipeline array.  The
+ * counter in the element should never be greater than 1, otherwise, the
+ * RCU implementation is broken.
+ */
+static int
+rcu_torture_reader(void *arg)
+{
+	unsigned long lastsleep = jiffies;
+	long myid = (long)arg;
+	int mynumonline = myid;
+	DEFINE_TORTURE_RANDOM(rand);
+	struct timer_list t;
+
+	VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
+	set_user_nice(current, MAX_NICE);
+	if (irqreader && cur_ops->irq_capable)
+		timer_setup_on_stack(&t, rcu_torture_timer, 0);
+	tick_dep_set_task(current, TICK_DEP_BIT_RCU);
+	do {
+		if (irqreader && cur_ops->irq_capable) {
+			if (!timer_pending(&t))
+				mod_timer(&t, jiffies + 1);
+		}
+		if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop())
+			schedule_timeout_interruptible(HZ);
+		if (time_after(jiffies, lastsleep) && !torture_must_stop()) {
+			torture_hrtimeout_us(500, 1000, &rand);
+			lastsleep = jiffies + 10;
+		}
+		while (torture_num_online_cpus() < mynumonline && !torture_must_stop())
+			schedule_timeout_interruptible(HZ / 5);
+		stutter_wait("rcu_torture_reader");
+	} while (!torture_must_stop());
+	if (irqreader && cur_ops->irq_capable) {
+		del_timer_sync(&t);
+		destroy_timer_on_stack(&t);
+	}
+	tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
+	torture_kthread_stopping("rcu_torture_reader");
+	return 0;
+}
+
+/*
+ * Randomly Toggle CPUs' callback-offload state.  This uses hrtimers to
+ * increase race probabilities and fuzzes the interval between toggling.
+ */
+static int rcu_nocb_toggle(void *arg)
+{
+	int cpu;
+	int maxcpu = -1;
+	int oldnice = task_nice(current);
+	long r;
+	DEFINE_TORTURE_RANDOM(rand);
+	ktime_t toggle_delay;
+	unsigned long toggle_fuzz;
+	ktime_t toggle_interval = ms_to_ktime(nocbs_toggle);
+
+	VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started");
+	while (!rcu_inkernel_boot_has_ended())
+		schedule_timeout_interruptible(HZ / 10);
+	for_each_online_cpu(cpu)
+		maxcpu = cpu;
+	WARN_ON(maxcpu < 0);
+	if (toggle_interval > ULONG_MAX)
+		toggle_fuzz = ULONG_MAX >> 3;
+	else
+		toggle_fuzz = toggle_interval >> 3;
+	if (toggle_fuzz <= 0)
+		toggle_fuzz = NSEC_PER_USEC;
+	do {
+		r = torture_random(&rand);
+		cpu = (r >> 4) % (maxcpu + 1);
+		if (r & 0x1) {
+			rcu_nocb_cpu_offload(cpu);
+			atomic_long_inc(&n_nocb_offload);
+		} else {
+			rcu_nocb_cpu_deoffload(cpu);
+			atomic_long_inc(&n_nocb_deoffload);
+		}
+		toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval;
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL);
+		if (stutter_wait("rcu_nocb_toggle"))
+			sched_set_normal(current, oldnice);
+	} while (!torture_must_stop());
+	torture_kthread_stopping("rcu_nocb_toggle");
+	return 0;
+}
+
+/*
+ * Print torture statistics.  Caller must ensure that there is only
+ * one call to this function at a given time!!!  This is normally
+ * accomplished by relying on the module system to only have one copy
+ * of the module loaded, and then by giving the rcu_torture_stats
+ * kthread full control (or the init/cleanup functions when rcu_torture_stats
+ * thread is not running).
+ */
+static void
+rcu_torture_stats_print(void)
+{
+	int cpu;
+	int i;
+	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
+	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
+	struct rcu_torture *rtcp;
+	static unsigned long rtcv_snap = ULONG_MAX;
+	static bool splatted;
+	struct task_struct *wtp;
+
+	for_each_possible_cpu(cpu) {
+		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
+			pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]);
+			batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]);
+		}
+	}
+	for (i = RCU_TORTURE_PIPE_LEN; i >= 0; i--) {
+		if (pipesummary[i] != 0)
+			break;
+	}
+
+	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
+	rtcp = rcu_access_pointer(rcu_torture_current);
+	pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
+		rtcp,
+		rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER",
+		rcu_torture_current_version,
+		list_empty(&rcu_torture_freelist),
+		atomic_read(&n_rcu_torture_alloc),
+		atomic_read(&n_rcu_torture_alloc_fail),
+		atomic_read(&n_rcu_torture_free));
+	pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld rtbre: %ld ",
+		atomic_read(&n_rcu_torture_mberror),
+		atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries),
+		n_rcu_torture_barrier_error,
+		n_rcu_torture_boost_ktrerror,
+		n_rcu_torture_boost_rterror);
+	pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
+		n_rcu_torture_boost_failure,
+		n_rcu_torture_boosts,
+		atomic_long_read(&n_rcu_torture_timers));
+	torture_onoff_stats();
+	pr_cont("barrier: %ld/%ld:%ld ",
+		data_race(n_barrier_successes),
+		data_race(n_barrier_attempts),
+		data_race(n_rcu_torture_barrier_error));
+	pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic.
+	pr_cont("nocb-toggles: %ld:%ld\n",
+		atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload));
+
+	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
+	if (atomic_read(&n_rcu_torture_mberror) ||
+	    atomic_read(&n_rcu_torture_mbchk_fail) ||
+	    n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
+	    n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure ||
+	    i > 1) {
+		pr_cont("%s", "!!! ");
+		atomic_inc(&n_rcu_torture_error);
+		WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
+		WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail));
+		WARN_ON_ONCE(n_rcu_torture_barrier_error);  // rcu_barrier()
+		WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
+		WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio
+		WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?)
+		WARN_ON_ONCE(i > 1); // Too-short grace period
+	}
+	pr_cont("Reader Pipe: ");
+	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
+		pr_cont(" %ld", pipesummary[i]);
+	pr_cont("\n");
+
+	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
+	pr_cont("Reader Batch: ");
+	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
+		pr_cont(" %ld", batchsummary[i]);
+	pr_cont("\n");
+
+	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
+	pr_cont("Free-Block Circulation: ");
+	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
+		pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
+	}
+	pr_cont("\n");
+
+	if (cur_ops->stats)
+		cur_ops->stats();
+	if (rtcv_snap == rcu_torture_current_version &&
+	    rcu_access_pointer(rcu_torture_current) &&
+	    !rcu_stall_is_suppressed()) {
+		int __maybe_unused flags = 0;
+		unsigned long __maybe_unused gp_seq = 0;
+
+		rcutorture_get_gp_data(cur_ops->ttype,
+				       &flags, &gp_seq);
+		srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
+					&flags, &gp_seq);
+		wtp = READ_ONCE(writer_task);
+		pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n",
+			 rcu_torture_writer_state_getname(),
+			 rcu_torture_writer_state, gp_seq, flags,
+			 wtp == NULL ? ~0U : wtp->__state,
+			 wtp == NULL ? -1 : (int)task_cpu(wtp));
+		if (!splatted && wtp) {
+			sched_show_task(wtp);
+			splatted = true;
+		}
+		if (cur_ops->gp_kthread_dbg)
+			cur_ops->gp_kthread_dbg();
+		rcu_ftrace_dump(DUMP_ALL);
+	}
+	rtcv_snap = rcu_torture_current_version;
+}
+
+/*
+ * Periodically prints torture statistics, if periodic statistics printing
+ * was specified via the stat_interval module parameter.
+ */
+static int
+rcu_torture_stats(void *arg)
+{
+	VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
+	do {
+		schedule_timeout_interruptible(stat_interval * HZ);
+		rcu_torture_stats_print();
+		torture_shutdown_absorb("rcu_torture_stats");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("rcu_torture_stats");
+	return 0;
+}
+
+/* Test mem_dump_obj() and friends.  */
+static void rcu_torture_mem_dump_obj(void)
+{
+	struct rcu_head *rhp;
+	struct kmem_cache *kcp;
+	static int z;
+
+	kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
+	if (WARN_ON_ONCE(!kcp))
+		return;
+	rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
+	if (WARN_ON_ONCE(!rhp)) {
+		kmem_cache_destroy(kcp);
+		return;
+	}
+	pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
+	pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
+	mem_dump_obj(ZERO_SIZE_PTR);
+	pr_alert("mem_dump_obj(NULL):");
+	mem_dump_obj(NULL);
+	pr_alert("mem_dump_obj(%px):", &rhp);
+	mem_dump_obj(&rhp);
+	pr_alert("mem_dump_obj(%px):", rhp);
+	mem_dump_obj(rhp);
+	pr_alert("mem_dump_obj(%px):", &rhp->func);
+	mem_dump_obj(&rhp->func);
+	pr_alert("mem_dump_obj(%px):", &z);
+	mem_dump_obj(&z);
+	kmem_cache_free(kcp, rhp);
+	kmem_cache_destroy(kcp);
+	rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
+	if (WARN_ON_ONCE(!rhp))
+		return;
+	pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
+	pr_alert("mem_dump_obj(kmalloc %px):", rhp);
+	mem_dump_obj(rhp);
+	pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
+	mem_dump_obj(&rhp->func);
+	kfree(rhp);
+	rhp = vmalloc(4096);
+	if (WARN_ON_ONCE(!rhp))
+		return;
+	pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
+	pr_alert("mem_dump_obj(vmalloc %px):", rhp);
+	mem_dump_obj(rhp);
+	pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
+	mem_dump_obj(&rhp->func);
+	vfree(rhp);
+}
+
+static void
+rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
+{
+	pr_alert("%s" TORTURE_FLAG
+		 "--- %s: nreaders=%d nfakewriters=%d "
+		 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
+		 "shuffle_interval=%d stutter=%d irqreader=%d "
+		 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
+		 "test_boost=%d/%d test_boost_interval=%d "
+		 "test_boost_duration=%d shutdown_secs=%d "
+		 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
+		 "stall_cpu_block=%d "
+		 "n_barrier_cbs=%d "
+		 "onoff_interval=%d onoff_holdoff=%d "
+		 "read_exit_delay=%d read_exit_burst=%d "
+		 "nocbs_nthreads=%d nocbs_toggle=%d\n",
+		 torture_type, tag, nrealreaders, nfakewriters,
+		 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
+		 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
+		 test_boost, cur_ops->can_boost,
+		 test_boost_interval, test_boost_duration, shutdown_secs,
+		 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
+		 stall_cpu_block,
+		 n_barrier_cbs,
+		 onoff_interval, onoff_holdoff,
+		 read_exit_delay, read_exit_burst,
+		 nocbs_nthreads, nocbs_toggle);
+}
+
+static int rcutorture_booster_cleanup(unsigned int cpu)
+{
+	struct task_struct *t;
+
+	if (boost_tasks[cpu] == NULL)
+		return 0;
+	mutex_lock(&boost_mutex);
+	t = boost_tasks[cpu];
+	boost_tasks[cpu] = NULL;
+	rcu_torture_enable_rt_throttle();
+	mutex_unlock(&boost_mutex);
+
+	/* This must be outside of the mutex, otherwise deadlock! */
+	torture_stop_kthread(rcu_torture_boost, t);
+	return 0;
+}
+
+static int rcutorture_booster_init(unsigned int cpu)
+{
+	int retval;
+
+	if (boost_tasks[cpu] != NULL)
+		return 0;  /* Already created, nothing more to do. */
+
+	// Testing RCU priority boosting requires rcutorture do
+	// some serious abuse.  Counter this by running ksoftirqd
+	// at higher priority.
+	if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) {
+		struct sched_param sp;
+		struct task_struct *t;
+
+		t = per_cpu(ksoftirqd, cpu);
+		WARN_ON_ONCE(!t);
+		sp.sched_priority = 2;
+		sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
+	}
+
+	/* Don't allow time recalculation while creating a new task. */
+	mutex_lock(&boost_mutex);
+	rcu_torture_disable_rt_throttle();
+	VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
+	boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL,
+					      cpu, "rcu_torture_boost_%u");
+	if (IS_ERR(boost_tasks[cpu])) {
+		retval = PTR_ERR(boost_tasks[cpu]);
+		VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
+		n_rcu_torture_boost_ktrerror++;
+		boost_tasks[cpu] = NULL;
+		mutex_unlock(&boost_mutex);
+		return retval;
+	}
+	mutex_unlock(&boost_mutex);
+	return 0;
+}
+
+/*
+ * CPU-stall kthread.  It waits as specified by stall_cpu_holdoff, then
+ * induces a CPU stall for the time specified by stall_cpu.
+ */
+static int rcu_torture_stall(void *args)
+{
+	int idx;
+	unsigned long stop_at;
+
+	VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
+	if (stall_cpu_holdoff > 0) {
+		VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
+		schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
+		VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
+	}
+	if (!kthread_should_stop() && stall_gp_kthread > 0) {
+		VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall");
+		rcu_gp_set_torture_wait(stall_gp_kthread * HZ);
+		for (idx = 0; idx < stall_gp_kthread + 2; idx++) {
+			if (kthread_should_stop())
+				break;
+			schedule_timeout_uninterruptible(HZ);
+		}
+	}
+	if (!kthread_should_stop() && stall_cpu > 0) {
+		VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall");
+		stop_at = ktime_get_seconds() + stall_cpu;
+		/* RCU CPU stall is expected behavior in following code. */
+		idx = cur_ops->readlock();
+		if (stall_cpu_irqsoff)
+			local_irq_disable();
+		else if (!stall_cpu_block)
+			preempt_disable();
+		pr_alert("%s start on CPU %d.\n",
+			  __func__, raw_smp_processor_id());
+		while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),
+				    stop_at))
+			if (stall_cpu_block) {
+#ifdef CONFIG_PREEMPTION
+				preempt_schedule();
+#else
+				schedule_timeout_uninterruptible(HZ);
+#endif
+			} else if (stall_no_softlockup) {
+				touch_softlockup_watchdog();
+			}
+		if (stall_cpu_irqsoff)
+			local_irq_enable();
+		else if (!stall_cpu_block)
+			preempt_enable();
+		cur_ops->readunlock(idx);
+	}
+	pr_alert("%s end.\n", __func__);
+	torture_shutdown_absorb("rcu_torture_stall");
+	while (!kthread_should_stop())
+		schedule_timeout_interruptible(10 * HZ);
+	return 0;
+}
+
+/* Spawn CPU-stall kthread, if stall_cpu specified. */
+static int __init rcu_torture_stall_init(void)
+{
+	if (stall_cpu <= 0 && stall_gp_kthread <= 0)
+		return 0;
+	return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
+}
+
+/* State structure for forward-progress self-propagating RCU callback. */
+struct fwd_cb_state {
+	struct rcu_head rh;
+	int stop;
+};
+
+/*
+ * Forward-progress self-propagating RCU callback function.  Because
+ * callbacks run from softirq, this function is an implicit RCU read-side
+ * critical section.
+ */
+static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
+{
+	struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
+
+	if (READ_ONCE(fcsp->stop)) {
+		WRITE_ONCE(fcsp->stop, 2);
+		return;
+	}
+	cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
+}
+
+/* State for continuous-flood RCU callbacks. */
+struct rcu_fwd_cb {
+	struct rcu_head rh;
+	struct rcu_fwd_cb *rfc_next;
+	struct rcu_fwd *rfc_rfp;
+	int rfc_gps;
+};
+
+#define MAX_FWD_CB_JIFFIES	(8 * HZ) /* Maximum CB test duration. */
+#define MIN_FWD_CB_LAUNDERS	3	/* This many CB invocations to count. */
+#define MIN_FWD_CBS_LAUNDERED	100	/* Number of counted CBs. */
+#define FWD_CBS_HIST_DIV	10	/* Histogram buckets/second. */
+#define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
+
+struct rcu_launder_hist {
+	long n_launders;
+	unsigned long launder_gp_seq;
+};
+
+struct rcu_fwd {
+	spinlock_t rcu_fwd_lock;
+	struct rcu_fwd_cb *rcu_fwd_cb_head;
+	struct rcu_fwd_cb **rcu_fwd_cb_tail;
+	long n_launders_cb;
+	unsigned long rcu_fwd_startat;
+	struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
+	unsigned long rcu_launder_gp_seq_start;
+	int rcu_fwd_id;
+};
+
+static DEFINE_MUTEX(rcu_fwd_mutex);
+static struct rcu_fwd *rcu_fwds;
+static unsigned long rcu_fwd_seq;
+static atomic_long_t rcu_fwd_max_cbs;
+static bool rcu_fwd_emergency_stop;
+
+static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
+{
+	unsigned long gps;
+	unsigned long gps_old;
+	int i;
+	int j;
+
+	for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
+		if (rfp->n_launders_hist[i].n_launders > 0)
+			break;
+	pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):",
+		 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat);
+	gps_old = rfp->rcu_launder_gp_seq_start;
+	for (j = 0; j <= i; j++) {
+		gps = rfp->n_launders_hist[j].launder_gp_seq;
+		pr_cont(" %ds/%d: %ld:%ld",
+			j + 1, FWD_CBS_HIST_DIV,
+			rfp->n_launders_hist[j].n_launders,
+			rcutorture_seq_diff(gps, gps_old));
+		gps_old = gps;
+	}
+	pr_cont("\n");
+}
+
+/* Callback function for continuous-flood RCU callbacks. */
+static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
+{
+	unsigned long flags;
+	int i;
+	struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
+	struct rcu_fwd_cb **rfcpp;
+	struct rcu_fwd *rfp = rfcp->rfc_rfp;
+
+	rfcp->rfc_next = NULL;
+	rfcp->rfc_gps++;
+	spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
+	rfcpp = rfp->rcu_fwd_cb_tail;
+	rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
+	WRITE_ONCE(*rfcpp, rfcp);
+	WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
+	i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
+	if (i >= ARRAY_SIZE(rfp->n_launders_hist))
+		i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
+	rfp->n_launders_hist[i].n_launders++;
+	rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
+	spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
+}
+
+// Give the scheduler a chance, even on nohz_full CPUs.
+static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
+{
+	if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
+		// Real call_rcu() floods hit userspace, so emulate that.
+		if (need_resched() || (iter & 0xfff))
+			schedule();
+		return;
+	}
+	// No userspace emulation: CB invocation throttles call_rcu()
+	cond_resched();
+}
+
+/*
+ * Free all callbacks on the rcu_fwd_cb_head list, either because the
+ * test is over or because we hit an OOM event.
+ */
+static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
+{
+	unsigned long flags;
+	unsigned long freed = 0;
+	struct rcu_fwd_cb *rfcp;
+
+	for (;;) {
+		spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
+		rfcp = rfp->rcu_fwd_cb_head;
+		if (!rfcp) {
+			spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
+			break;
+		}
+		rfp->rcu_fwd_cb_head = rfcp->rfc_next;
+		if (!rfp->rcu_fwd_cb_head)
+			rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
+		spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
+		kfree(rfcp);
+		freed++;
+		rcu_torture_fwd_prog_cond_resched(freed);
+		if (tick_nohz_full_enabled()) {
+			local_irq_save(flags);
+			rcu_momentary_dyntick_idle();
+			local_irq_restore(flags);
+		}
+	}
+	return freed;
+}
+
+/* Carry out need_resched()/cond_resched() forward-progress testing. */
+static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
+				    int *tested, int *tested_tries)
+{
+	unsigned long cver;
+	unsigned long dur;
+	struct fwd_cb_state fcs;
+	unsigned long gps;
+	int idx;
+	int sd;
+	int sd4;
+	bool selfpropcb = false;
+	unsigned long stopat;
+	static DEFINE_TORTURE_RANDOM(trs);
+
+	pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
+	if (!cur_ops->sync)
+		return; // Cannot do need_resched() forward progress testing without ->sync.
+	if (cur_ops->call && cur_ops->cb_barrier) {
+		init_rcu_head_on_stack(&fcs.rh);
+		selfpropcb = true;
+	}
+
+	/* Tight loop containing cond_resched(). */
+	atomic_inc(&rcu_fwd_cb_nodelay);
+	cur_ops->sync(); /* Later readers see above write. */
+	if  (selfpropcb) {
+		WRITE_ONCE(fcs.stop, 0);
+		cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
+	}
+	cver = READ_ONCE(rcu_torture_current_version);
+	gps = cur_ops->get_gp_seq();
+	sd = cur_ops->stall_dur() + 1;
+	sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
+	dur = sd4 + torture_random(&trs) % (sd - sd4);
+	WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
+	stopat = rfp->rcu_fwd_startat + dur;
+	while (time_before(jiffies, stopat) &&
+	       !shutdown_time_arrived() &&
+	       !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
+		idx = cur_ops->readlock();
+		udelay(10);
+		cur_ops->readunlock(idx);
+		if (!fwd_progress_need_resched || need_resched())
+			cond_resched();
+	}
+	(*tested_tries)++;
+	if (!time_before(jiffies, stopat) &&
+	    !shutdown_time_arrived() &&
+	    !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
+		(*tested)++;
+		cver = READ_ONCE(rcu_torture_current_version) - cver;
+		gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
+		WARN_ON(!cver && gps < 2);
+		pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__,
+			 rfp->rcu_fwd_id, dur, cver, gps);
+	}
+	if (selfpropcb) {
+		WRITE_ONCE(fcs.stop, 1);
+		cur_ops->sync(); /* Wait for running CB to complete. */
+		pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
+		cur_ops->cb_barrier(); /* Wait for queued callbacks. */
+	}
+
+	if (selfpropcb) {
+		WARN_ON(READ_ONCE(fcs.stop) != 2);
+		destroy_rcu_head_on_stack(&fcs.rh);
+	}
+	schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
+	atomic_dec(&rcu_fwd_cb_nodelay);
+}
+
+/* Carry out call_rcu() forward-progress testing. */
+static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
+{
+	unsigned long cver;
+	unsigned long flags;
+	unsigned long gps;
+	int i;
+	long n_launders;
+	long n_launders_cb_snap;
+	long n_launders_sa;
+	long n_max_cbs;
+	long n_max_gps;
+	struct rcu_fwd_cb *rfcp;
+	struct rcu_fwd_cb *rfcpn;
+	unsigned long stopat;
+	unsigned long stoppedat;
+
+	pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
+	if (READ_ONCE(rcu_fwd_emergency_stop))
+		return; /* Get out of the way quickly, no GP wait! */
+	if (!cur_ops->call)
+		return; /* Can't do call_rcu() fwd prog without ->call. */
+
+	/* Loop continuously posting RCU callbacks. */
+	atomic_inc(&rcu_fwd_cb_nodelay);
+	cur_ops->sync(); /* Later readers see above write. */
+	WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
+	stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
+	n_launders = 0;
+	rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
+	n_launders_sa = 0;
+	n_max_cbs = 0;
+	n_max_gps = 0;
+	for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
+		rfp->n_launders_hist[i].n_launders = 0;
+	cver = READ_ONCE(rcu_torture_current_version);
+	gps = cur_ops->get_gp_seq();
+	rfp->rcu_launder_gp_seq_start = gps;
+	tick_dep_set_task(current, TICK_DEP_BIT_RCU);
+	while (time_before(jiffies, stopat) &&
+	       !shutdown_time_arrived() &&
+	       !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
+		rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
+		rfcpn = NULL;
+		if (rfcp)
+			rfcpn = READ_ONCE(rfcp->rfc_next);
+		if (rfcpn) {
+			if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
+			    ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
+				break;
+			rfp->rcu_fwd_cb_head = rfcpn;
+			n_launders++;
+			n_launders_sa++;
+		} else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) {
+			rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
+			if (WARN_ON_ONCE(!rfcp)) {
+				schedule_timeout_interruptible(1);
+				continue;
+			}
+			n_max_cbs++;
+			n_launders_sa = 0;
+			rfcp->rfc_gps = 0;
+			rfcp->rfc_rfp = rfp;
+		} else {
+			rfcp = NULL;
+		}
+		if (rfcp)
+			cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
+		rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
+		if (tick_nohz_full_enabled()) {
+			local_irq_save(flags);
+			rcu_momentary_dyntick_idle();
+			local_irq_restore(flags);
+		}
+	}
+	stoppedat = jiffies;
+	n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
+	cver = READ_ONCE(rcu_torture_current_version) - cver;
+	gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
+	pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
+	cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
+	(void)rcu_torture_fwd_prog_cbfree(rfp);
+
+	if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
+	    !shutdown_time_arrived()) {
+		WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
+		pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld\n",
+			 __func__,
+			 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
+			 n_launders + n_max_cbs - n_launders_cb_snap,
+			 n_launders, n_launders_sa,
+			 n_max_gps, n_max_cbs, cver, gps);
+		atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs);
+		mutex_lock(&rcu_fwd_mutex); // Serialize histograms.
+		rcu_torture_fwd_cb_hist(rfp);
+		mutex_unlock(&rcu_fwd_mutex);
+	}
+	schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
+	tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
+	atomic_dec(&rcu_fwd_cb_nodelay);
+}
+
+
+/*
+ * OOM notifier, but this only prints diagnostic information for the
+ * current forward-progress test.
+ */
+static int rcutorture_oom_notify(struct notifier_block *self,
+				 unsigned long notused, void *nfreed)
+{
+	int i;
+	long ncbs;
+	struct rcu_fwd *rfp;
+
+	mutex_lock(&rcu_fwd_mutex);
+	rfp = rcu_fwds;
+	if (!rfp) {
+		mutex_unlock(&rcu_fwd_mutex);
+		return NOTIFY_OK;
+	}
+	WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
+	     __func__);
+	for (i = 0; i < fwd_progress; i++) {
+		rcu_torture_fwd_cb_hist(&rfp[i]);
+		rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2);
+	}
+	WRITE_ONCE(rcu_fwd_emergency_stop, true);
+	smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
+	ncbs = 0;
+	for (i = 0; i < fwd_progress; i++)
+		ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
+	pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
+	cur_ops->cb_barrier();
+	ncbs = 0;
+	for (i = 0; i < fwd_progress; i++)
+		ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
+	pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
+	cur_ops->cb_barrier();
+	ncbs = 0;
+	for (i = 0; i < fwd_progress; i++)
+		ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
+	pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
+	smp_mb(); /* Frees before return to avoid redoing OOM. */
+	(*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
+	pr_info("%s returning after OOM processing.\n", __func__);
+	mutex_unlock(&rcu_fwd_mutex);
+	return NOTIFY_OK;
+}
+
+static struct notifier_block rcutorture_oom_nb = {
+	.notifier_call = rcutorture_oom_notify
+};
+
+/* Carry out grace-period forward-progress testing. */
+static int rcu_torture_fwd_prog(void *args)
+{
+	bool firsttime = true;
+	long max_cbs;
+	int oldnice = task_nice(current);
+	unsigned long oldseq = READ_ONCE(rcu_fwd_seq);
+	struct rcu_fwd *rfp = args;
+	int tested = 0;
+	int tested_tries = 0;
+
+	VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
+	rcu_bind_current_to_nocb();
+	if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
+		set_user_nice(current, MAX_NICE);
+	do {
+		if (!rfp->rcu_fwd_id) {
+			schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
+			WRITE_ONCE(rcu_fwd_emergency_stop, false);
+			if (!firsttime) {
+				max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0);
+				pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs);
+			}
+			firsttime = false;
+			WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1);
+		} else {
+			while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop())
+				schedule_timeout_interruptible(1);
+			oldseq = READ_ONCE(rcu_fwd_seq);
+		}
+		pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
+		if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id)
+			rcu_torture_fwd_prog_cr(rfp);
+		if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) &&
+		    (!IS_ENABLED(CONFIG_TINY_RCU) ||
+		     (rcu_inkernel_boot_has_ended() &&
+		      torture_num_online_cpus() > rfp->rcu_fwd_id)))
+			rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
+
+		/* Avoid slow periods, better to test when busy. */
+		if (stutter_wait("rcu_torture_fwd_prog"))
+			sched_set_normal(current, oldnice);
+	} while (!torture_must_stop());
+	/* Short runs might not contain a valid forward-progress attempt. */
+	if (!rfp->rcu_fwd_id) {
+		WARN_ON(!tested && tested_tries >= 5);
+		pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
+	}
+	torture_kthread_stopping("rcu_torture_fwd_prog");
+	return 0;
+}
+
+/* If forward-progress checking is requested and feasible, spawn the thread. */
+static int __init rcu_torture_fwd_prog_init(void)
+{
+	int i;
+	int ret = 0;
+	struct rcu_fwd *rfp;
+
+	if (!fwd_progress)
+		return 0; /* Not requested, so don't do it. */
+	if (fwd_progress >= nr_cpu_ids) {
+		VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n");
+		fwd_progress = nr_cpu_ids;
+	} else if (fwd_progress < 0) {
+		fwd_progress = nr_cpu_ids;
+	}
+	if ((!cur_ops->sync && !cur_ops->call) ||
+	    (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) ||
+	    cur_ops == &rcu_busted_ops) {
+		VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
+		fwd_progress = 0;
+		return 0;
+	}
+	if (stall_cpu > 0) {
+		VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
+		fwd_progress = 0;
+		if (IS_MODULE(CONFIG_RCU_TORTURE_TEST))
+			return -EINVAL; /* In module, can fail back to user. */
+		WARN_ON(1); /* Make sure rcutorture notices conflict. */
+		return 0;
+	}
+	if (fwd_progress_holdoff <= 0)
+		fwd_progress_holdoff = 1;
+	if (fwd_progress_div <= 0)
+		fwd_progress_div = 4;
+	rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL);
+	fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL);
+	if (!rfp || !fwd_prog_tasks) {
+		kfree(rfp);
+		kfree(fwd_prog_tasks);
+		fwd_prog_tasks = NULL;
+		fwd_progress = 0;
+		return -ENOMEM;
+	}
+	for (i = 0; i < fwd_progress; i++) {
+		spin_lock_init(&rfp[i].rcu_fwd_lock);
+		rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head;
+		rfp[i].rcu_fwd_id = i;
+	}
+	mutex_lock(&rcu_fwd_mutex);
+	rcu_fwds = rfp;
+	mutex_unlock(&rcu_fwd_mutex);
+	register_oom_notifier(&rcutorture_oom_nb);
+	for (i = 0; i < fwd_progress; i++) {
+		ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]);
+		if (ret) {
+			fwd_progress = i;
+			return ret;
+		}
+	}
+	return 0;
+}
+
+static void rcu_torture_fwd_prog_cleanup(void)
+{
+	int i;
+	struct rcu_fwd *rfp;
+
+	if (!rcu_fwds || !fwd_prog_tasks)
+		return;
+	for (i = 0; i < fwd_progress; i++)
+		torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]);
+	unregister_oom_notifier(&rcutorture_oom_nb);
+	mutex_lock(&rcu_fwd_mutex);
+	rfp = rcu_fwds;
+	rcu_fwds = NULL;
+	mutex_unlock(&rcu_fwd_mutex);
+	kfree(rfp);
+	kfree(fwd_prog_tasks);
+	fwd_prog_tasks = NULL;
+}
+
+/* Callback function for RCU barrier testing. */
+static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
+{
+	atomic_inc(&barrier_cbs_invoked);
+}
+
+/* IPI handler to get callback posted on desired CPU, if online. */
+static void rcu_torture_barrier1cb(void *rcu_void)
+{
+	struct rcu_head *rhp = rcu_void;
+
+	cur_ops->call(rhp, rcu_torture_barrier_cbf);
+}
+
+/* kthread function to register callbacks used to test RCU barriers. */
+static int rcu_torture_barrier_cbs(void *arg)
+{
+	long myid = (long)arg;
+	bool lastphase = false;
+	bool newphase;
+	struct rcu_head rcu;
+
+	init_rcu_head_on_stack(&rcu);
+	VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
+	set_user_nice(current, MAX_NICE);
+	do {
+		wait_event(barrier_cbs_wq[myid],
+			   (newphase =
+			    smp_load_acquire(&barrier_phase)) != lastphase ||
+			   torture_must_stop());
+		lastphase = newphase;
+		if (torture_must_stop())
+			break;
+		/*
+		 * The above smp_load_acquire() ensures barrier_phase load
+		 * is ordered before the following ->call().
+		 */
+		if (smp_call_function_single(myid, rcu_torture_barrier1cb,
+					     &rcu, 1)) {
+			// IPI failed, so use direct call from current CPU.
+			cur_ops->call(&rcu, rcu_torture_barrier_cbf);
+		}
+		if (atomic_dec_and_test(&barrier_cbs_count))
+			wake_up(&barrier_wq);
+	} while (!torture_must_stop());
+	if (cur_ops->cb_barrier != NULL)
+		cur_ops->cb_barrier();
+	destroy_rcu_head_on_stack(&rcu);
+	torture_kthread_stopping("rcu_torture_barrier_cbs");
+	return 0;
+}
+
+/* kthread function to drive and coordinate RCU barrier testing. */
+static int rcu_torture_barrier(void *arg)
+{
+	int i;
+
+	VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
+	do {
+		atomic_set(&barrier_cbs_invoked, 0);
+		atomic_set(&barrier_cbs_count, n_barrier_cbs);
+		/* Ensure barrier_phase ordered after prior assignments. */
+		smp_store_release(&barrier_phase, !barrier_phase);
+		for (i = 0; i < n_barrier_cbs; i++)
+			wake_up(&barrier_cbs_wq[i]);
+		wait_event(barrier_wq,
+			   atomic_read(&barrier_cbs_count) == 0 ||
+			   torture_must_stop());
+		if (torture_must_stop())
+			break;
+		n_barrier_attempts++;
+		cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
+		if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
+			n_rcu_torture_barrier_error++;
+			pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
+			       atomic_read(&barrier_cbs_invoked),
+			       n_barrier_cbs);
+			WARN_ON(1);
+			// Wait manually for the remaining callbacks
+			i = 0;
+			do {
+				if (WARN_ON(i++ > HZ))
+					i = INT_MIN;
+				schedule_timeout_interruptible(1);
+				cur_ops->cb_barrier();
+			} while (atomic_read(&barrier_cbs_invoked) !=
+				 n_barrier_cbs &&
+				 !torture_must_stop());
+			smp_mb(); // Can't trust ordering if broken.
+			if (!torture_must_stop())
+				pr_err("Recovered: barrier_cbs_invoked = %d\n",
+				       atomic_read(&barrier_cbs_invoked));
+		} else {
+			n_barrier_successes++;
+		}
+		schedule_timeout_interruptible(HZ / 10);
+	} while (!torture_must_stop());
+	torture_kthread_stopping("rcu_torture_barrier");
+	return 0;
+}
+
+/* Initialize RCU barrier testing. */
+static int rcu_torture_barrier_init(void)
+{
+	int i;
+	int ret;
+
+	if (n_barrier_cbs <= 0)
+		return 0;
+	if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
+		pr_alert("%s" TORTURE_FLAG
+			 " Call or barrier ops missing for %s,\n",
+			 torture_type, cur_ops->name);
+		pr_alert("%s" TORTURE_FLAG
+			 " RCU barrier testing omitted from run.\n",
+			 torture_type);
+		return 0;
+	}
+	atomic_set(&barrier_cbs_count, 0);
+	atomic_set(&barrier_cbs_invoked, 0);
+	barrier_cbs_tasks =
+		kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
+			GFP_KERNEL);
+	barrier_cbs_wq =
+		kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
+	if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
+		return -ENOMEM;
+	for (i = 0; i < n_barrier_cbs; i++) {
+		init_waitqueue_head(&barrier_cbs_wq[i]);
+		ret = torture_create_kthread(rcu_torture_barrier_cbs,
+					     (void *)(long)i,
+					     barrier_cbs_tasks[i]);
+		if (ret)
+			return ret;
+	}
+	return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
+}
+
+/* Clean up after RCU barrier testing. */
+static void rcu_torture_barrier_cleanup(void)
+{
+	int i;
+
+	torture_stop_kthread(rcu_torture_barrier, barrier_task);
+	if (barrier_cbs_tasks != NULL) {
+		for (i = 0; i < n_barrier_cbs; i++)
+			torture_stop_kthread(rcu_torture_barrier_cbs,
+					     barrier_cbs_tasks[i]);
+		kfree(barrier_cbs_tasks);
+		barrier_cbs_tasks = NULL;
+	}
+	if (barrier_cbs_wq != NULL) {
+		kfree(barrier_cbs_wq);
+		barrier_cbs_wq = NULL;
+	}
+}
+
+static bool rcu_torture_can_boost(void)
+{
+	static int boost_warn_once;
+	int prio;
+
+	if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
+		return false;
+	if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)
+		return false;
+
+	prio = rcu_get_gp_kthreads_prio();
+	if (!prio)
+		return false;
+
+	if (prio < 2) {
+		if (boost_warn_once == 1)
+			return false;
+
+		pr_alert("%s: WARN: RCU kthread priority too low to test boosting.  Skipping RCU boost test. Try passing rcutree.kthread_prio > 1 on the kernel command line.\n", KBUILD_MODNAME);
+		boost_warn_once = 1;
+		return false;
+	}
+
+	return true;
+}
+
+static bool read_exit_child_stop;
+static bool read_exit_child_stopped;
+static wait_queue_head_t read_exit_wq;
+
+// Child kthread which just does an rcutorture reader and exits.
+static int rcu_torture_read_exit_child(void *trsp_in)
+{
+	struct torture_random_state *trsp = trsp_in;
+
+	set_user_nice(current, MAX_NICE);
+	// Minimize time between reading and exiting.
+	while (!kthread_should_stop())
+		schedule_timeout_uninterruptible(1);
+	(void)rcu_torture_one_read(trsp, -1);
+	return 0;
+}
+
+// Parent kthread which creates and destroys read-exit child kthreads.
+static int rcu_torture_read_exit(void *unused)
+{
+	bool errexit = false;
+	int i;
+	struct task_struct *tsp;
+	DEFINE_TORTURE_RANDOM(trs);
+
+	// Allocate and initialize.
+	set_user_nice(current, MAX_NICE);
+	VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test");
+
+	// Each pass through this loop does one read-exit episode.
+	do {
+		VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode");
+		for (i = 0; i < read_exit_burst; i++) {
+			if (READ_ONCE(read_exit_child_stop))
+				break;
+			stutter_wait("rcu_torture_read_exit");
+			// Spawn child.
+			tsp = kthread_run(rcu_torture_read_exit_child,
+					  &trs, "%s", "rcu_torture_read_exit_child");
+			if (IS_ERR(tsp)) {
+				TOROUT_ERRSTRING("out of memory");
+				errexit = true;
+				break;
+			}
+			cond_resched();
+			kthread_stop(tsp);
+			n_read_exits++;
+		}
+		VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode");
+		rcu_barrier(); // Wait for task_struct free, avoid OOM.
+		i = 0;
+		for (; !errexit && !READ_ONCE(read_exit_child_stop) && i < read_exit_delay; i++)
+			schedule_timeout_uninterruptible(HZ);
+	} while (!errexit && !READ_ONCE(read_exit_child_stop));
+
+	// Clean up and exit.
+	smp_store_release(&read_exit_child_stopped, true); // After reaping.
+	smp_mb(); // Store before wakeup.
+	wake_up(&read_exit_wq);
+	while (!torture_must_stop())
+		schedule_timeout_uninterruptible(1);
+	torture_kthread_stopping("rcu_torture_read_exit");
+	return 0;
+}
+
+static int rcu_torture_read_exit_init(void)
+{
+	if (read_exit_burst <= 0)
+		return 0;
+	init_waitqueue_head(&read_exit_wq);
+	read_exit_child_stop = false;
+	read_exit_child_stopped = false;
+	return torture_create_kthread(rcu_torture_read_exit, NULL,
+				      read_exit_task);
+}
+
+static void rcu_torture_read_exit_cleanup(void)
+{
+	if (!read_exit_task)
+		return;
+	WRITE_ONCE(read_exit_child_stop, true);
+	smp_mb(); // Above write before wait.
+	wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped));
+	torture_stop_kthread(rcutorture_read_exit, read_exit_task);
+}
+
+static enum cpuhp_state rcutor_hp;
+
+static void
+rcu_torture_cleanup(void)
+{
+	int firsttime;
+	int flags = 0;
+	unsigned long gp_seq = 0;
+	int i;
+
+	if (torture_cleanup_begin()) {
+		if (cur_ops->cb_barrier != NULL) {
+			pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
+			cur_ops->cb_barrier();
+		}
+		rcu_gp_slow_unregister(NULL);
+		return;
+	}
+	if (!cur_ops) {
+		torture_cleanup_end();
+		rcu_gp_slow_unregister(NULL);
+		return;
+	}
+
+	if (cur_ops->gp_kthread_dbg)
+		cur_ops->gp_kthread_dbg();
+	rcu_torture_read_exit_cleanup();
+	rcu_torture_barrier_cleanup();
+	rcu_torture_fwd_prog_cleanup();
+	torture_stop_kthread(rcu_torture_stall, stall_task);
+	torture_stop_kthread(rcu_torture_writer, writer_task);
+
+	if (nocb_tasks) {
+		for (i = 0; i < nrealnocbers; i++)
+			torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]);
+		kfree(nocb_tasks);
+		nocb_tasks = NULL;
+	}
+
+	if (reader_tasks) {
+		for (i = 0; i < nrealreaders; i++)
+			torture_stop_kthread(rcu_torture_reader,
+					     reader_tasks[i]);
+		kfree(reader_tasks);
+		reader_tasks = NULL;
+	}
+	kfree(rcu_torture_reader_mbchk);
+	rcu_torture_reader_mbchk = NULL;
+
+	if (fakewriter_tasks) {
+		for (i = 0; i < nfakewriters; i++)
+			torture_stop_kthread(rcu_torture_fakewriter,
+					     fakewriter_tasks[i]);
+		kfree(fakewriter_tasks);
+		fakewriter_tasks = NULL;
+	}
+
+	rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
+	srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
+	pr_alert("%s:  End-test grace-period state: g%ld f%#x total-gps=%ld\n",
+		 cur_ops->name, (long)gp_seq, flags,
+		 rcutorture_seq_diff(gp_seq, start_gp_seq));
+	torture_stop_kthread(rcu_torture_stats, stats_task);
+	torture_stop_kthread(rcu_torture_fqs, fqs_task);
+	if (rcu_torture_can_boost() && rcutor_hp >= 0)
+		cpuhp_remove_state(rcutor_hp);
+
+	/*
+	 * Wait for all RCU callbacks to fire, then do torture-type-specific
+	 * cleanup operations.
+	 */
+	if (cur_ops->cb_barrier != NULL) {
+		pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
+		cur_ops->cb_barrier();
+	}
+	if (cur_ops->cleanup != NULL)
+		cur_ops->cleanup();
+
+	rcu_torture_mem_dump_obj();
+
+	rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
+
+	if (err_segs_recorded) {
+		pr_alert("Failure/close-call rcutorture reader segments:\n");
+		if (rt_read_nsegs == 0)
+			pr_alert("\t: No segments recorded!!!\n");
+		firsttime = 1;
+		for (i = 0; i < rt_read_nsegs; i++) {
+			pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate);
+			if (err_segs[i].rt_delay_jiffies != 0) {
+				pr_cont("%s%ldjiffies", firsttime ? "" : "+",
+					err_segs[i].rt_delay_jiffies);
+				firsttime = 0;
+			}
+			if (err_segs[i].rt_delay_ms != 0) {
+				pr_cont("%s%ldms", firsttime ? "" : "+",
+					err_segs[i].rt_delay_ms);
+				firsttime = 0;
+			}
+			if (err_segs[i].rt_delay_us != 0) {
+				pr_cont("%s%ldus", firsttime ? "" : "+",
+					err_segs[i].rt_delay_us);
+				firsttime = 0;
+			}
+			pr_cont("%s\n",
+				err_segs[i].rt_preempted ? "preempted" : "");
+
+		}
+	}
+	if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
+		rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
+	else if (torture_onoff_failures())
+		rcu_torture_print_module_parms(cur_ops,
+					       "End of test: RCU_HOTPLUG");
+	else
+		rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
+	torture_cleanup_end();
+	rcu_gp_slow_unregister(&rcu_fwd_cb_nodelay);
+}
+
+#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
+static void rcu_torture_leak_cb(struct rcu_head *rhp)
+{
+}
+
+static void rcu_torture_err_cb(struct rcu_head *rhp)
+{
+	/*
+	 * This -might- happen due to race conditions, but is unlikely.
+	 * The scenario that leads to this happening is that the
+	 * first of the pair of duplicate callbacks is queued,
+	 * someone else starts a grace period that includes that
+	 * callback, then the second of the pair must wait for the
+	 * next grace period.  Unlikely, but can happen.  If it
+	 * does happen, the debug-objects subsystem won't have splatted.
+	 */
+	pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
+}
+#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+
+/*
+ * Verify that double-free causes debug-objects to complain, but only
+ * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y.  Otherwise, say that the test
+ * cannot be carried out.
+ */
+static void rcu_test_debug_objects(void)
+{
+#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
+	struct rcu_head rh1;
+	struct rcu_head rh2;
+	struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
+
+	init_rcu_head_on_stack(&rh1);
+	init_rcu_head_on_stack(&rh2);
+	pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
+
+	/* Try to queue the rh2 pair of callbacks for the same grace period. */
+	preempt_disable(); /* Prevent preemption from interrupting test. */
+	rcu_read_lock(); /* Make it impossible to finish a grace period. */
+	call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
+	local_irq_disable(); /* Make it harder to start a new grace period. */
+	call_rcu(&rh2, rcu_torture_leak_cb);
+	call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
+	if (rhp) {
+		call_rcu(rhp, rcu_torture_leak_cb);
+		call_rcu(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
+	}
+	local_irq_enable();
+	rcu_read_unlock();
+	preempt_enable();
+
+	/* Wait for them all to get done so we can safely return. */
+	rcu_barrier();
+	pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
+	destroy_rcu_head_on_stack(&rh1);
+	destroy_rcu_head_on_stack(&rh2);
+	kfree(rhp);
+#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+	pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
+#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+}
+
+static void rcutorture_sync(void)
+{
+	static unsigned long n;
+
+	if (cur_ops->sync && !(++n & 0xfff))
+		cur_ops->sync();
+}
+
+static int __init
+rcu_torture_init(void)
+{
+	long i;
+	int cpu;
+	int firsterr = 0;
+	int flags = 0;
+	unsigned long gp_seq = 0;
+	static struct rcu_torture_ops *torture_ops[] = {
+		&rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, &busted_srcud_ops,
+		TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
+		&trivial_ops,
+	};
+
+	if (!torture_init_begin(torture_type, verbose))
+		return -EBUSY;
+
+	/* Process args and tell the world that the torturer is on the job. */
+	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
+		cur_ops = torture_ops[i];
+		if (strcmp(torture_type, cur_ops->name) == 0)
+			break;
+	}
+	if (i == ARRAY_SIZE(torture_ops)) {
+		pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
+			 torture_type);
+		pr_alert("rcu-torture types:");
+		for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
+			pr_cont(" %s", torture_ops[i]->name);
+		pr_cont("\n");
+		firsterr = -EINVAL;
+		cur_ops = NULL;
+		goto unwind;
+	}
+	if (cur_ops->fqs == NULL && fqs_duration != 0) {
+		pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
+		fqs_duration = 0;
+	}
+	if (cur_ops->init)
+		cur_ops->init();
+
+	if (nreaders >= 0) {
+		nrealreaders = nreaders;
+	} else {
+		nrealreaders = num_online_cpus() - 2 - nreaders;
+		if (nrealreaders <= 0)
+			nrealreaders = 1;
+	}
+	rcu_torture_print_module_parms(cur_ops, "Start of test");
+	rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
+	srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
+	start_gp_seq = gp_seq;
+	pr_alert("%s:  Start-test grace-period state: g%ld f%#x\n",
+		 cur_ops->name, (long)gp_seq, flags);
+
+	/* Set up the freelist. */
+
+	INIT_LIST_HEAD(&rcu_torture_freelist);
+	for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
+		rcu_tortures[i].rtort_mbtest = 0;
+		list_add_tail(&rcu_tortures[i].rtort_free,
+			      &rcu_torture_freelist);
+	}
+
+	/* Initialize the statistics so that each run gets its own numbers. */
+
+	rcu_torture_current = NULL;
+	rcu_torture_current_version = 0;
+	atomic_set(&n_rcu_torture_alloc, 0);
+	atomic_set(&n_rcu_torture_alloc_fail, 0);
+	atomic_set(&n_rcu_torture_free, 0);
+	atomic_set(&n_rcu_torture_mberror, 0);
+	atomic_set(&n_rcu_torture_mbchk_fail, 0);
+	atomic_set(&n_rcu_torture_mbchk_tries, 0);
+	atomic_set(&n_rcu_torture_error, 0);
+	n_rcu_torture_barrier_error = 0;
+	n_rcu_torture_boost_ktrerror = 0;
+	n_rcu_torture_boost_rterror = 0;
+	n_rcu_torture_boost_failure = 0;
+	n_rcu_torture_boosts = 0;
+	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
+		atomic_set(&rcu_torture_wcount[i], 0);
+	for_each_possible_cpu(cpu) {
+		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
+			per_cpu(rcu_torture_count, cpu)[i] = 0;
+			per_cpu(rcu_torture_batch, cpu)[i] = 0;
+		}
+	}
+	err_segs_recorded = 0;
+	rt_read_nsegs = 0;
+
+	/* Start up the kthreads. */
+
+	rcu_torture_write_types();
+	firsterr = torture_create_kthread(rcu_torture_writer, NULL,
+					  writer_task);
+	if (torture_init_error(firsterr))
+		goto unwind;
+	if (nfakewriters > 0) {
+		fakewriter_tasks = kcalloc(nfakewriters,
+					   sizeof(fakewriter_tasks[0]),
+					   GFP_KERNEL);
+		if (fakewriter_tasks == NULL) {
+			TOROUT_ERRSTRING("out of memory");
+			firsterr = -ENOMEM;
+			goto unwind;
+		}
+	}
+	for (i = 0; i < nfakewriters; i++) {
+		firsterr = torture_create_kthread(rcu_torture_fakewriter,
+						  NULL, fakewriter_tasks[i]);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
+			       GFP_KERNEL);
+	rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk),
+					   GFP_KERNEL);
+	if (!reader_tasks || !rcu_torture_reader_mbchk) {
+		TOROUT_ERRSTRING("out of memory");
+		firsterr = -ENOMEM;
+		goto unwind;
+	}
+	for (i = 0; i < nrealreaders; i++) {
+		rcu_torture_reader_mbchk[i].rtc_chkrdr = -1;
+		firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
+						  reader_tasks[i]);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	nrealnocbers = nocbs_nthreads;
+	if (WARN_ON(nrealnocbers < 0))
+		nrealnocbers = 1;
+	if (WARN_ON(nocbs_toggle < 0))
+		nocbs_toggle = HZ;
+	if (nrealnocbers > 0) {
+		nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL);
+		if (nocb_tasks == NULL) {
+			TOROUT_ERRSTRING("out of memory");
+			firsterr = -ENOMEM;
+			goto unwind;
+		}
+	} else {
+		nocb_tasks = NULL;
+	}
+	for (i = 0; i < nrealnocbers; i++) {
+		firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	if (stat_interval > 0) {
+		firsterr = torture_create_kthread(rcu_torture_stats, NULL,
+						  stats_task);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	if (test_no_idle_hz && shuffle_interval > 0) {
+		firsterr = torture_shuffle_init(shuffle_interval * HZ);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	if (stutter < 0)
+		stutter = 0;
+	if (stutter) {
+		int t;
+
+		t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
+		firsterr = torture_stutter_init(stutter * HZ, t);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	if (fqs_duration < 0)
+		fqs_duration = 0;
+	if (fqs_duration) {
+		/* Create the fqs thread */
+		firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
+						  fqs_task);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	if (test_boost_interval < 1)
+		test_boost_interval = 1;
+	if (test_boost_duration < 2)
+		test_boost_duration = 2;
+	if (rcu_torture_can_boost()) {
+
+		boost_starttime = jiffies + test_boost_interval * HZ;
+
+		firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
+					     rcutorture_booster_init,
+					     rcutorture_booster_cleanup);
+		rcutor_hp = firsterr;
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	shutdown_jiffies = jiffies + shutdown_secs * HZ;
+	firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
+	if (torture_init_error(firsterr))
+		goto unwind;
+	firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
+				      rcutorture_sync);
+	if (torture_init_error(firsterr))
+		goto unwind;
+	firsterr = rcu_torture_stall_init();
+	if (torture_init_error(firsterr))
+		goto unwind;
+	firsterr = rcu_torture_fwd_prog_init();
+	if (torture_init_error(firsterr))
+		goto unwind;
+	firsterr = rcu_torture_barrier_init();
+	if (torture_init_error(firsterr))
+		goto unwind;
+	firsterr = rcu_torture_read_exit_init();
+	if (torture_init_error(firsterr))
+		goto unwind;
+	if (object_debug)
+		rcu_test_debug_objects();
+	torture_init_end();
+	rcu_gp_slow_register(&rcu_fwd_cb_nodelay);
+	return 0;
+
+unwind:
+	torture_init_end();
+	rcu_torture_cleanup();
+	if (shutdown_secs) {
+		WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
+		kernel_power_off();
+	}
+	return firsterr;
+}
+
+module_init(rcu_torture_init);
+module_exit(rcu_torture_cleanup);
diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
new file mode 100644
index 000000000..3a93c53f6
--- /dev/null
+++ b/kernel/rcu/refscale.c
@@ -0,0 +1,897 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Scalability test comparing RCU vs other mechanisms
+// for acquiring references on objects.
+//
+// Copyright (C) Google, 2020.
+//
+// Author: Joel Fernandes <joel@joelfernandes.org>
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kthread.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/notifier.h>
+#include <linux/percpu.h>
+#include <linux/rcupdate.h>
+#include <linux/rcupdate_trace.h>
+#include <linux/reboot.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+#include <linux/stat.h>
+#include <linux/srcu.h>
+#include <linux/slab.h>
+#include <linux/torture.h>
+#include <linux/types.h>
+
+#include "rcu.h"
+
+#define SCALE_FLAG "-ref-scale: "
+
+#define SCALEOUT(s, x...) \
+	pr_alert("%s" SCALE_FLAG s, scale_type, ## x)
+
+#define VERBOSE_SCALEOUT(s, x...) \
+	do { \
+		if (verbose) \
+			pr_alert("%s" SCALE_FLAG s "\n", scale_type, ## x); \
+	} while (0)
+
+static atomic_t verbose_batch_ctr;
+
+#define VERBOSE_SCALEOUT_BATCH(s, x...)							\
+do {											\
+	if (verbose &&									\
+	    (verbose_batched <= 0 ||							\
+	     !(atomic_inc_return(&verbose_batch_ctr) % verbose_batched))) {		\
+		schedule_timeout_uninterruptible(1);					\
+		pr_alert("%s" SCALE_FLAG s "\n", scale_type, ## x);			\
+	}										\
+} while (0)
+
+#define SCALEOUT_ERRSTRING(s, x...) pr_alert("%s" SCALE_FLAG "!!! " s "\n", scale_type, ## x)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Joel Fernandes (Google) <joel@joelfernandes.org>");
+
+static char *scale_type = "rcu";
+module_param(scale_type, charp, 0444);
+MODULE_PARM_DESC(scale_type, "Type of test (rcu, srcu, refcnt, rwsem, rwlock.");
+
+torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
+torture_param(int, verbose_batched, 0, "Batch verbose debugging printk()s");
+
+// Wait until there are multiple CPUs before starting test.
+torture_param(int, holdoff, IS_BUILTIN(CONFIG_RCU_REF_SCALE_TEST) ? 10 : 0,
+	      "Holdoff time before test start (s)");
+// Number of loops per experiment, all readers execute operations concurrently.
+torture_param(long, loops, 10000, "Number of loops per experiment.");
+// Number of readers, with -1 defaulting to about 75% of the CPUs.
+torture_param(int, nreaders, -1, "Number of readers, -1 for 75% of CPUs.");
+// Number of runs.
+torture_param(int, nruns, 30, "Number of experiments to run.");
+// Reader delay in nanoseconds, 0 for no delay.
+torture_param(int, readdelay, 0, "Read-side delay in nanoseconds.");
+
+#ifdef MODULE
+# define REFSCALE_SHUTDOWN 0
+#else
+# define REFSCALE_SHUTDOWN 1
+#endif
+
+torture_param(bool, shutdown, REFSCALE_SHUTDOWN,
+	      "Shutdown at end of scalability tests.");
+
+struct reader_task {
+	struct task_struct *task;
+	int start_reader;
+	wait_queue_head_t wq;
+	u64 last_duration_ns;
+};
+
+static struct task_struct *shutdown_task;
+static wait_queue_head_t shutdown_wq;
+
+static struct task_struct *main_task;
+static wait_queue_head_t main_wq;
+static int shutdown_start;
+
+static struct reader_task *reader_tasks;
+
+// Number of readers that are part of the current experiment.
+static atomic_t nreaders_exp;
+
+// Use to wait for all threads to start.
+static atomic_t n_init;
+static atomic_t n_started;
+static atomic_t n_warmedup;
+static atomic_t n_cooleddown;
+
+// Track which experiment is currently running.
+static int exp_idx;
+
+// Operations vector for selecting different types of tests.
+struct ref_scale_ops {
+	void (*init)(void);
+	void (*cleanup)(void);
+	void (*readsection)(const int nloops);
+	void (*delaysection)(const int nloops, const int udl, const int ndl);
+	const char *name;
+};
+
+static struct ref_scale_ops *cur_ops;
+
+static void un_delay(const int udl, const int ndl)
+{
+	if (udl)
+		udelay(udl);
+	if (ndl)
+		ndelay(ndl);
+}
+
+static void ref_rcu_read_section(const int nloops)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		rcu_read_lock();
+		rcu_read_unlock();
+	}
+}
+
+static void ref_rcu_delay_section(const int nloops, const int udl, const int ndl)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		rcu_read_lock();
+		un_delay(udl, ndl);
+		rcu_read_unlock();
+	}
+}
+
+static void rcu_sync_scale_init(void)
+{
+}
+
+static struct ref_scale_ops rcu_ops = {
+	.init		= rcu_sync_scale_init,
+	.readsection	= ref_rcu_read_section,
+	.delaysection	= ref_rcu_delay_section,
+	.name		= "rcu"
+};
+
+// Definitions for SRCU ref scale testing.
+DEFINE_STATIC_SRCU(srcu_refctl_scale);
+static struct srcu_struct *srcu_ctlp = &srcu_refctl_scale;
+
+static void srcu_ref_scale_read_section(const int nloops)
+{
+	int i;
+	int idx;
+
+	for (i = nloops; i >= 0; i--) {
+		idx = srcu_read_lock(srcu_ctlp);
+		srcu_read_unlock(srcu_ctlp, idx);
+	}
+}
+
+static void srcu_ref_scale_delay_section(const int nloops, const int udl, const int ndl)
+{
+	int i;
+	int idx;
+
+	for (i = nloops; i >= 0; i--) {
+		idx = srcu_read_lock(srcu_ctlp);
+		un_delay(udl, ndl);
+		srcu_read_unlock(srcu_ctlp, idx);
+	}
+}
+
+static struct ref_scale_ops srcu_ops = {
+	.init		= rcu_sync_scale_init,
+	.readsection	= srcu_ref_scale_read_section,
+	.delaysection	= srcu_ref_scale_delay_section,
+	.name		= "srcu"
+};
+
+#ifdef CONFIG_TASKS_RCU
+
+// Definitions for RCU Tasks ref scale testing: Empty read markers.
+// These definitions also work for RCU Rude readers.
+static void rcu_tasks_ref_scale_read_section(const int nloops)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--)
+		continue;
+}
+
+static void rcu_tasks_ref_scale_delay_section(const int nloops, const int udl, const int ndl)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--)
+		un_delay(udl, ndl);
+}
+
+static struct ref_scale_ops rcu_tasks_ops = {
+	.init		= rcu_sync_scale_init,
+	.readsection	= rcu_tasks_ref_scale_read_section,
+	.delaysection	= rcu_tasks_ref_scale_delay_section,
+	.name		= "rcu-tasks"
+};
+
+#define RCU_TASKS_OPS &rcu_tasks_ops,
+
+#else // #ifdef CONFIG_TASKS_RCU
+
+#define RCU_TASKS_OPS
+
+#endif // #else // #ifdef CONFIG_TASKS_RCU
+
+#ifdef CONFIG_TASKS_TRACE_RCU
+
+// Definitions for RCU Tasks Trace ref scale testing.
+static void rcu_trace_ref_scale_read_section(const int nloops)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		rcu_read_lock_trace();
+		rcu_read_unlock_trace();
+	}
+}
+
+static void rcu_trace_ref_scale_delay_section(const int nloops, const int udl, const int ndl)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		rcu_read_lock_trace();
+		un_delay(udl, ndl);
+		rcu_read_unlock_trace();
+	}
+}
+
+static struct ref_scale_ops rcu_trace_ops = {
+	.init		= rcu_sync_scale_init,
+	.readsection	= rcu_trace_ref_scale_read_section,
+	.delaysection	= rcu_trace_ref_scale_delay_section,
+	.name		= "rcu-trace"
+};
+
+#define RCU_TRACE_OPS &rcu_trace_ops,
+
+#else // #ifdef CONFIG_TASKS_TRACE_RCU
+
+#define RCU_TRACE_OPS
+
+#endif // #else // #ifdef CONFIG_TASKS_TRACE_RCU
+
+// Definitions for reference count
+static atomic_t refcnt;
+
+static void ref_refcnt_section(const int nloops)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		atomic_inc(&refcnt);
+		atomic_dec(&refcnt);
+	}
+}
+
+static void ref_refcnt_delay_section(const int nloops, const int udl, const int ndl)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		atomic_inc(&refcnt);
+		un_delay(udl, ndl);
+		atomic_dec(&refcnt);
+	}
+}
+
+static struct ref_scale_ops refcnt_ops = {
+	.init		= rcu_sync_scale_init,
+	.readsection	= ref_refcnt_section,
+	.delaysection	= ref_refcnt_delay_section,
+	.name		= "refcnt"
+};
+
+// Definitions for rwlock
+static rwlock_t test_rwlock;
+
+static void ref_rwlock_init(void)
+{
+	rwlock_init(&test_rwlock);
+}
+
+static void ref_rwlock_section(const int nloops)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		read_lock(&test_rwlock);
+		read_unlock(&test_rwlock);
+	}
+}
+
+static void ref_rwlock_delay_section(const int nloops, const int udl, const int ndl)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		read_lock(&test_rwlock);
+		un_delay(udl, ndl);
+		read_unlock(&test_rwlock);
+	}
+}
+
+static struct ref_scale_ops rwlock_ops = {
+	.init		= ref_rwlock_init,
+	.readsection	= ref_rwlock_section,
+	.delaysection	= ref_rwlock_delay_section,
+	.name		= "rwlock"
+};
+
+// Definitions for rwsem
+static struct rw_semaphore test_rwsem;
+
+static void ref_rwsem_init(void)
+{
+	init_rwsem(&test_rwsem);
+}
+
+static void ref_rwsem_section(const int nloops)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		down_read(&test_rwsem);
+		up_read(&test_rwsem);
+	}
+}
+
+static void ref_rwsem_delay_section(const int nloops, const int udl, const int ndl)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		down_read(&test_rwsem);
+		un_delay(udl, ndl);
+		up_read(&test_rwsem);
+	}
+}
+
+static struct ref_scale_ops rwsem_ops = {
+	.init		= ref_rwsem_init,
+	.readsection	= ref_rwsem_section,
+	.delaysection	= ref_rwsem_delay_section,
+	.name		= "rwsem"
+};
+
+// Definitions for global spinlock
+static DEFINE_RAW_SPINLOCK(test_lock);
+
+static void ref_lock_section(const int nloops)
+{
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		raw_spin_lock(&test_lock);
+		raw_spin_unlock(&test_lock);
+	}
+	preempt_enable();
+}
+
+static void ref_lock_delay_section(const int nloops, const int udl, const int ndl)
+{
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		raw_spin_lock(&test_lock);
+		un_delay(udl, ndl);
+		raw_spin_unlock(&test_lock);
+	}
+	preempt_enable();
+}
+
+static struct ref_scale_ops lock_ops = {
+	.readsection	= ref_lock_section,
+	.delaysection	= ref_lock_delay_section,
+	.name		= "lock"
+};
+
+// Definitions for global irq-save spinlock
+
+static void ref_lock_irq_section(const int nloops)
+{
+	unsigned long flags;
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		raw_spin_lock_irqsave(&test_lock, flags);
+		raw_spin_unlock_irqrestore(&test_lock, flags);
+	}
+	preempt_enable();
+}
+
+static void ref_lock_irq_delay_section(const int nloops, const int udl, const int ndl)
+{
+	unsigned long flags;
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		raw_spin_lock_irqsave(&test_lock, flags);
+		un_delay(udl, ndl);
+		raw_spin_unlock_irqrestore(&test_lock, flags);
+	}
+	preempt_enable();
+}
+
+static struct ref_scale_ops lock_irq_ops = {
+	.readsection	= ref_lock_irq_section,
+	.delaysection	= ref_lock_irq_delay_section,
+	.name		= "lock-irq"
+};
+
+// Definitions acquire-release.
+static DEFINE_PER_CPU(unsigned long, test_acqrel);
+
+static void ref_acqrel_section(const int nloops)
+{
+	unsigned long x;
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		x = smp_load_acquire(this_cpu_ptr(&test_acqrel));
+		smp_store_release(this_cpu_ptr(&test_acqrel), x + 1);
+	}
+	preempt_enable();
+}
+
+static void ref_acqrel_delay_section(const int nloops, const int udl, const int ndl)
+{
+	unsigned long x;
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		x = smp_load_acquire(this_cpu_ptr(&test_acqrel));
+		un_delay(udl, ndl);
+		smp_store_release(this_cpu_ptr(&test_acqrel), x + 1);
+	}
+	preempt_enable();
+}
+
+static struct ref_scale_ops acqrel_ops = {
+	.readsection	= ref_acqrel_section,
+	.delaysection	= ref_acqrel_delay_section,
+	.name		= "acqrel"
+};
+
+static volatile u64 stopopts;
+
+static void ref_clock_section(const int nloops)
+{
+	u64 x = 0;
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--)
+		x += ktime_get_real_fast_ns();
+	preempt_enable();
+	stopopts = x;
+}
+
+static void ref_clock_delay_section(const int nloops, const int udl, const int ndl)
+{
+	u64 x = 0;
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		x += ktime_get_real_fast_ns();
+		un_delay(udl, ndl);
+	}
+	preempt_enable();
+	stopopts = x;
+}
+
+static struct ref_scale_ops clock_ops = {
+	.readsection	= ref_clock_section,
+	.delaysection	= ref_clock_delay_section,
+	.name		= "clock"
+};
+
+static void rcu_scale_one_reader(void)
+{
+	if (readdelay <= 0)
+		cur_ops->readsection(loops);
+	else
+		cur_ops->delaysection(loops, readdelay / 1000, readdelay % 1000);
+}
+
+// Reader kthread.  Repeatedly does empty RCU read-side
+// critical section, minimizing update-side interference.
+static int
+ref_scale_reader(void *arg)
+{
+	unsigned long flags;
+	long me = (long)arg;
+	struct reader_task *rt = &(reader_tasks[me]);
+	u64 start;
+	s64 duration;
+
+	VERBOSE_SCALEOUT_BATCH("ref_scale_reader %ld: task started", me);
+	WARN_ON_ONCE(set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids)));
+	set_user_nice(current, MAX_NICE);
+	atomic_inc(&n_init);
+	if (holdoff)
+		schedule_timeout_interruptible(holdoff * HZ);
+repeat:
+	VERBOSE_SCALEOUT_BATCH("ref_scale_reader %ld: waiting to start next experiment on cpu %d", me, raw_smp_processor_id());
+
+	// Wait for signal that this reader can start.
+	wait_event(rt->wq, (atomic_read(&nreaders_exp) && smp_load_acquire(&rt->start_reader)) ||
+			   torture_must_stop());
+
+	if (torture_must_stop())
+		goto end;
+
+	// Make sure that the CPU is affinitized appropriately during testing.
+	WARN_ON_ONCE(raw_smp_processor_id() != me);
+
+	WRITE_ONCE(rt->start_reader, 0);
+	if (!atomic_dec_return(&n_started))
+		while (atomic_read_acquire(&n_started))
+			cpu_relax();
+
+	VERBOSE_SCALEOUT_BATCH("ref_scale_reader %ld: experiment %d started", me, exp_idx);
+
+
+	// To reduce noise, do an initial cache-warming invocation, check
+	// in, and then keep warming until everyone has checked in.
+	rcu_scale_one_reader();
+	if (!atomic_dec_return(&n_warmedup))
+		while (atomic_read_acquire(&n_warmedup))
+			rcu_scale_one_reader();
+	// Also keep interrupts disabled.  This also has the effect
+	// of preventing entries into slow path for rcu_read_unlock().
+	local_irq_save(flags);
+	start = ktime_get_mono_fast_ns();
+
+	rcu_scale_one_reader();
+
+	duration = ktime_get_mono_fast_ns() - start;
+	local_irq_restore(flags);
+
+	rt->last_duration_ns = WARN_ON_ONCE(duration < 0) ? 0 : duration;
+	// To reduce runtime-skew noise, do maintain-load invocations until
+	// everyone is done.
+	if (!atomic_dec_return(&n_cooleddown))
+		while (atomic_read_acquire(&n_cooleddown))
+			rcu_scale_one_reader();
+
+	if (atomic_dec_and_test(&nreaders_exp))
+		wake_up(&main_wq);
+
+	VERBOSE_SCALEOUT_BATCH("ref_scale_reader %ld: experiment %d ended, (readers remaining=%d)",
+				me, exp_idx, atomic_read(&nreaders_exp));
+
+	if (!torture_must_stop())
+		goto repeat;
+end:
+	torture_kthread_stopping("ref_scale_reader");
+	return 0;
+}
+
+static void reset_readers(void)
+{
+	int i;
+	struct reader_task *rt;
+
+	for (i = 0; i < nreaders; i++) {
+		rt = &(reader_tasks[i]);
+
+		rt->last_duration_ns = 0;
+	}
+}
+
+// Print the results of each reader and return the sum of all their durations.
+static u64 process_durations(int n)
+{
+	int i;
+	struct reader_task *rt;
+	char buf1[64];
+	char *buf;
+	u64 sum = 0;
+
+	buf = kmalloc(800 + 64, GFP_KERNEL);
+	if (!buf)
+		return 0;
+	buf[0] = 0;
+	sprintf(buf, "Experiment #%d (Format: <THREAD-NUM>:<Total loop time in ns>)",
+		exp_idx);
+
+	for (i = 0; i < n && !torture_must_stop(); i++) {
+		rt = &(reader_tasks[i]);
+		sprintf(buf1, "%d: %llu\t", i, rt->last_duration_ns);
+
+		if (i % 5 == 0)
+			strcat(buf, "\n");
+		if (strlen(buf) >= 800) {
+			pr_alert("%s", buf);
+			buf[0] = 0;
+		}
+		strcat(buf, buf1);
+
+		sum += rt->last_duration_ns;
+	}
+	pr_alert("%s\n", buf);
+
+	kfree(buf);
+	return sum;
+}
+
+// The main_func is the main orchestrator, it performs a bunch of
+// experiments.  For every experiment, it orders all the readers
+// involved to start and waits for them to finish the experiment. It
+// then reads their timestamps and starts the next experiment. Each
+// experiment progresses from 1 concurrent reader to N of them at which
+// point all the timestamps are printed.
+static int main_func(void *arg)
+{
+	int exp, r;
+	char buf1[64];
+	char *buf;
+	u64 *result_avg;
+
+	set_cpus_allowed_ptr(current, cpumask_of(nreaders % nr_cpu_ids));
+	set_user_nice(current, MAX_NICE);
+
+	VERBOSE_SCALEOUT("main_func task started");
+	result_avg = kzalloc(nruns * sizeof(*result_avg), GFP_KERNEL);
+	buf = kzalloc(800 + 64, GFP_KERNEL);
+	if (!result_avg || !buf) {
+		SCALEOUT_ERRSTRING("out of memory");
+		goto oom_exit;
+	}
+	if (holdoff)
+		schedule_timeout_interruptible(holdoff * HZ);
+
+	// Wait for all threads to start.
+	atomic_inc(&n_init);
+	while (atomic_read(&n_init) < nreaders + 1)
+		schedule_timeout_uninterruptible(1);
+
+	// Start exp readers up per experiment
+	for (exp = 0; exp < nruns && !torture_must_stop(); exp++) {
+		if (torture_must_stop())
+			goto end;
+
+		reset_readers();
+		atomic_set(&nreaders_exp, nreaders);
+		atomic_set(&n_started, nreaders);
+		atomic_set(&n_warmedup, nreaders);
+		atomic_set(&n_cooleddown, nreaders);
+
+		exp_idx = exp;
+
+		for (r = 0; r < nreaders; r++) {
+			smp_store_release(&reader_tasks[r].start_reader, 1);
+			wake_up(&reader_tasks[r].wq);
+		}
+
+		VERBOSE_SCALEOUT("main_func: experiment started, waiting for %d readers",
+				nreaders);
+
+		wait_event(main_wq,
+			   !atomic_read(&nreaders_exp) || torture_must_stop());
+
+		VERBOSE_SCALEOUT("main_func: experiment ended");
+
+		if (torture_must_stop())
+			goto end;
+
+		result_avg[exp] = div_u64(1000 * process_durations(nreaders), nreaders * loops);
+	}
+
+	// Print the average of all experiments
+	SCALEOUT("END OF TEST. Calculating average duration per loop (nanoseconds)...\n");
+
+	pr_alert("Runs\tTime(ns)\n");
+	for (exp = 0; exp < nruns; exp++) {
+		u64 avg;
+		u32 rem;
+
+		avg = div_u64_rem(result_avg[exp], 1000, &rem);
+		sprintf(buf1, "%d\t%llu.%03u\n", exp + 1, avg, rem);
+		strcat(buf, buf1);
+		if (strlen(buf) >= 800) {
+			pr_alert("%s", buf);
+			buf[0] = 0;
+		}
+	}
+
+	pr_alert("%s", buf);
+
+oom_exit:
+	// This will shutdown everything including us.
+	if (shutdown) {
+		shutdown_start = 1;
+		wake_up(&shutdown_wq);
+	}
+
+	// Wait for torture to stop us
+	while (!torture_must_stop())
+		schedule_timeout_uninterruptible(1);
+
+end:
+	torture_kthread_stopping("main_func");
+	kfree(result_avg);
+	kfree(buf);
+	return 0;
+}
+
+static void
+ref_scale_print_module_parms(struct ref_scale_ops *cur_ops, const char *tag)
+{
+	pr_alert("%s" SCALE_FLAG
+		 "--- %s:  verbose=%d shutdown=%d holdoff=%d loops=%ld nreaders=%d nruns=%d readdelay=%d\n", scale_type, tag,
+		 verbose, shutdown, holdoff, loops, nreaders, nruns, readdelay);
+}
+
+static void
+ref_scale_cleanup(void)
+{
+	int i;
+
+	if (torture_cleanup_begin())
+		return;
+
+	if (!cur_ops) {
+		torture_cleanup_end();
+		return;
+	}
+
+	if (reader_tasks) {
+		for (i = 0; i < nreaders; i++)
+			torture_stop_kthread("ref_scale_reader",
+					     reader_tasks[i].task);
+	}
+	kfree(reader_tasks);
+
+	torture_stop_kthread("main_task", main_task);
+	kfree(main_task);
+
+	// Do scale-type-specific cleanup operations.
+	if (cur_ops->cleanup != NULL)
+		cur_ops->cleanup();
+
+	torture_cleanup_end();
+}
+
+// Shutdown kthread.  Just waits to be awakened, then shuts down system.
+static int
+ref_scale_shutdown(void *arg)
+{
+	wait_event_idle(shutdown_wq, shutdown_start);
+
+	smp_mb(); // Wake before output.
+	ref_scale_cleanup();
+	kernel_power_off();
+
+	return -EINVAL;
+}
+
+static int __init
+ref_scale_init(void)
+{
+	long i;
+	int firsterr = 0;
+	static struct ref_scale_ops *scale_ops[] = {
+		&rcu_ops, &srcu_ops, RCU_TRACE_OPS RCU_TASKS_OPS &refcnt_ops, &rwlock_ops,
+		&rwsem_ops, &lock_ops, &lock_irq_ops, &acqrel_ops, &clock_ops,
+	};
+
+	if (!torture_init_begin(scale_type, verbose))
+		return -EBUSY;
+
+	for (i = 0; i < ARRAY_SIZE(scale_ops); i++) {
+		cur_ops = scale_ops[i];
+		if (strcmp(scale_type, cur_ops->name) == 0)
+			break;
+	}
+	if (i == ARRAY_SIZE(scale_ops)) {
+		pr_alert("rcu-scale: invalid scale type: \"%s\"\n", scale_type);
+		pr_alert("rcu-scale types:");
+		for (i = 0; i < ARRAY_SIZE(scale_ops); i++)
+			pr_cont(" %s", scale_ops[i]->name);
+		pr_cont("\n");
+		firsterr = -EINVAL;
+		cur_ops = NULL;
+		goto unwind;
+	}
+	if (cur_ops->init)
+		cur_ops->init();
+
+	ref_scale_print_module_parms(cur_ops, "Start of test");
+
+	// Shutdown task
+	if (shutdown) {
+		init_waitqueue_head(&shutdown_wq);
+		firsterr = torture_create_kthread(ref_scale_shutdown, NULL,
+						  shutdown_task);
+		if (torture_init_error(firsterr))
+			goto unwind;
+		schedule_timeout_uninterruptible(1);
+	}
+
+	// Reader tasks (default to ~75% of online CPUs).
+	if (nreaders < 0)
+		nreaders = (num_online_cpus() >> 1) + (num_online_cpus() >> 2);
+	if (WARN_ONCE(loops <= 0, "%s: loops = %ld, adjusted to 1\n", __func__, loops))
+		loops = 1;
+	if (WARN_ONCE(nreaders <= 0, "%s: nreaders = %d, adjusted to 1\n", __func__, nreaders))
+		nreaders = 1;
+	if (WARN_ONCE(nruns <= 0, "%s: nruns = %d, adjusted to 1\n", __func__, nruns))
+		nruns = 1;
+	reader_tasks = kcalloc(nreaders, sizeof(reader_tasks[0]),
+			       GFP_KERNEL);
+	if (!reader_tasks) {
+		SCALEOUT_ERRSTRING("out of memory");
+		firsterr = -ENOMEM;
+		goto unwind;
+	}
+
+	VERBOSE_SCALEOUT("Starting %d reader threads", nreaders);
+
+	for (i = 0; i < nreaders; i++) {
+		init_waitqueue_head(&reader_tasks[i].wq);
+		firsterr = torture_create_kthread(ref_scale_reader, (void *)i,
+						  reader_tasks[i].task);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+
+	// Main Task
+	init_waitqueue_head(&main_wq);
+	firsterr = torture_create_kthread(main_func, NULL, main_task);
+	if (torture_init_error(firsterr))
+		goto unwind;
+
+	torture_init_end();
+	return 0;
+
+unwind:
+	torture_init_end();
+	ref_scale_cleanup();
+	if (shutdown) {
+		WARN_ON(!IS_MODULE(CONFIG_RCU_REF_SCALE_TEST));
+		kernel_power_off();
+	}
+	return firsterr;
+}
+
+module_init(ref_scale_init);
+module_exit(ref_scale_cleanup);
diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
new file mode 100644
index 000000000..33adafdad
--- /dev/null
+++ b/kernel/rcu/srcutiny.c
@@ -0,0 +1,272 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Sleepable Read-Copy Update mechanism for mutual exclusion,
+ *	tiny version for non-preemptible single-CPU use.
+ *
+ * Copyright (C) IBM Corporation, 2017
+ *
+ * Author: Paul McKenney <paulmck@linux.ibm.com>
+ */
+
+#include <linux/export.h>
+#include <linux/mutex.h>
+#include <linux/preempt.h>
+#include <linux/rcupdate_wait.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/srcu.h>
+
+#include <linux/rcu_node_tree.h>
+#include "rcu_segcblist.h"
+#include "rcu.h"
+
+int rcu_scheduler_active __read_mostly;
+static LIST_HEAD(srcu_boot_list);
+static bool srcu_init_done;
+
+static int init_srcu_struct_fields(struct srcu_struct *ssp)
+{
+	ssp->srcu_lock_nesting[0] = 0;
+	ssp->srcu_lock_nesting[1] = 0;
+	init_swait_queue_head(&ssp->srcu_wq);
+	ssp->srcu_cb_head = NULL;
+	ssp->srcu_cb_tail = &ssp->srcu_cb_head;
+	ssp->srcu_gp_running = false;
+	ssp->srcu_gp_waiting = false;
+	ssp->srcu_idx = 0;
+	ssp->srcu_idx_max = 0;
+	INIT_WORK(&ssp->srcu_work, srcu_drive_gp);
+	INIT_LIST_HEAD(&ssp->srcu_work.entry);
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
+int __init_srcu_struct(struct srcu_struct *ssp, const char *name,
+		       struct lock_class_key *key)
+{
+	/* Don't re-initialize a lock while it is held. */
+	debug_check_no_locks_freed((void *)ssp, sizeof(*ssp));
+	lockdep_init_map(&ssp->dep_map, name, key, 0);
+	return init_srcu_struct_fields(ssp);
+}
+EXPORT_SYMBOL_GPL(__init_srcu_struct);
+
+#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
+/*
+ * init_srcu_struct - initialize a sleep-RCU structure
+ * @ssp: structure to initialize.
+ *
+ * Must invoke this on a given srcu_struct before passing that srcu_struct
+ * to any other function.  Each srcu_struct represents a separate domain
+ * of SRCU protection.
+ */
+int init_srcu_struct(struct srcu_struct *ssp)
+{
+	return init_srcu_struct_fields(ssp);
+}
+EXPORT_SYMBOL_GPL(init_srcu_struct);
+
+#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
+/*
+ * cleanup_srcu_struct - deconstruct a sleep-RCU structure
+ * @ssp: structure to clean up.
+ *
+ * Must invoke this after you are finished using a given srcu_struct that
+ * was initialized via init_srcu_struct(), else you leak memory.
+ */
+void cleanup_srcu_struct(struct srcu_struct *ssp)
+{
+	WARN_ON(ssp->srcu_lock_nesting[0] || ssp->srcu_lock_nesting[1]);
+	flush_work(&ssp->srcu_work);
+	WARN_ON(ssp->srcu_gp_running);
+	WARN_ON(ssp->srcu_gp_waiting);
+	WARN_ON(ssp->srcu_cb_head);
+	WARN_ON(&ssp->srcu_cb_head != ssp->srcu_cb_tail);
+	WARN_ON(ssp->srcu_idx != ssp->srcu_idx_max);
+	WARN_ON(ssp->srcu_idx & 0x1);
+}
+EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
+
+/*
+ * Removes the count for the old reader from the appropriate element of
+ * the srcu_struct.
+ */
+void __srcu_read_unlock(struct srcu_struct *ssp, int idx)
+{
+	int newval = READ_ONCE(ssp->srcu_lock_nesting[idx]) - 1;
+
+	WRITE_ONCE(ssp->srcu_lock_nesting[idx], newval);
+	if (!newval && READ_ONCE(ssp->srcu_gp_waiting) && in_task())
+		swake_up_one(&ssp->srcu_wq);
+}
+EXPORT_SYMBOL_GPL(__srcu_read_unlock);
+
+/*
+ * Workqueue handler to drive one grace period and invoke any callbacks
+ * that become ready as a result.  Single-CPU and !PREEMPTION operation
+ * means that we get away with murder on synchronization.  ;-)
+ */
+void srcu_drive_gp(struct work_struct *wp)
+{
+	int idx;
+	struct rcu_head *lh;
+	struct rcu_head *rhp;
+	struct srcu_struct *ssp;
+
+	ssp = container_of(wp, struct srcu_struct, srcu_work);
+	if (ssp->srcu_gp_running || ULONG_CMP_GE(ssp->srcu_idx, READ_ONCE(ssp->srcu_idx_max)))
+		return; /* Already running or nothing to do. */
+
+	/* Remove recently arrived callbacks and wait for readers. */
+	WRITE_ONCE(ssp->srcu_gp_running, true);
+	local_irq_disable();
+	lh = ssp->srcu_cb_head;
+	ssp->srcu_cb_head = NULL;
+	ssp->srcu_cb_tail = &ssp->srcu_cb_head;
+	local_irq_enable();
+	idx = (ssp->srcu_idx & 0x2) / 2;
+	WRITE_ONCE(ssp->srcu_idx, ssp->srcu_idx + 1);
+	WRITE_ONCE(ssp->srcu_gp_waiting, true);  /* srcu_read_unlock() wakes! */
+	swait_event_exclusive(ssp->srcu_wq, !READ_ONCE(ssp->srcu_lock_nesting[idx]));
+	WRITE_ONCE(ssp->srcu_gp_waiting, false); /* srcu_read_unlock() cheap. */
+	WRITE_ONCE(ssp->srcu_idx, ssp->srcu_idx + 1);
+
+	/* Invoke the callbacks we removed above. */
+	while (lh) {
+		rhp = lh;
+		lh = lh->next;
+		local_bh_disable();
+		rhp->func(rhp);
+		local_bh_enable();
+	}
+
+	/*
+	 * Enable rescheduling, and if there are more callbacks,
+	 * reschedule ourselves.  This can race with a call_srcu()
+	 * at interrupt level, but the ->srcu_gp_running checks will
+	 * straighten that out.
+	 */
+	WRITE_ONCE(ssp->srcu_gp_running, false);
+	if (ULONG_CMP_LT(ssp->srcu_idx, READ_ONCE(ssp->srcu_idx_max)))
+		schedule_work(&ssp->srcu_work);
+}
+EXPORT_SYMBOL_GPL(srcu_drive_gp);
+
+static void srcu_gp_start_if_needed(struct srcu_struct *ssp)
+{
+	unsigned long cookie;
+
+	cookie = get_state_synchronize_srcu(ssp);
+	if (ULONG_CMP_GE(READ_ONCE(ssp->srcu_idx_max), cookie))
+		return;
+	WRITE_ONCE(ssp->srcu_idx_max, cookie);
+	if (!READ_ONCE(ssp->srcu_gp_running)) {
+		if (likely(srcu_init_done))
+			schedule_work(&ssp->srcu_work);
+		else if (list_empty(&ssp->srcu_work.entry))
+			list_add(&ssp->srcu_work.entry, &srcu_boot_list);
+	}
+}
+
+/*
+ * Enqueue an SRCU callback on the specified srcu_struct structure,
+ * initiating grace-period processing if it is not already running.
+ */
+void call_srcu(struct srcu_struct *ssp, struct rcu_head *rhp,
+	       rcu_callback_t func)
+{
+	unsigned long flags;
+
+	rhp->func = func;
+	rhp->next = NULL;
+	local_irq_save(flags);
+	*ssp->srcu_cb_tail = rhp;
+	ssp->srcu_cb_tail = &rhp->next;
+	local_irq_restore(flags);
+	srcu_gp_start_if_needed(ssp);
+}
+EXPORT_SYMBOL_GPL(call_srcu);
+
+/*
+ * synchronize_srcu - wait for prior SRCU read-side critical-section completion
+ */
+void synchronize_srcu(struct srcu_struct *ssp)
+{
+	struct rcu_synchronize rs;
+
+	init_rcu_head_on_stack(&rs.head);
+	init_completion(&rs.completion);
+	call_srcu(ssp, &rs.head, wakeme_after_rcu);
+	wait_for_completion(&rs.completion);
+	destroy_rcu_head_on_stack(&rs.head);
+}
+EXPORT_SYMBOL_GPL(synchronize_srcu);
+
+/*
+ * get_state_synchronize_srcu - Provide an end-of-grace-period cookie
+ */
+unsigned long get_state_synchronize_srcu(struct srcu_struct *ssp)
+{
+	unsigned long ret;
+
+	barrier();
+	ret = (READ_ONCE(ssp->srcu_idx) + 3) & ~0x1;
+	barrier();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(get_state_synchronize_srcu);
+
+/*
+ * start_poll_synchronize_srcu - Provide cookie and start grace period
+ *
+ * The difference between this and get_state_synchronize_srcu() is that
+ * this function ensures that the poll_state_synchronize_srcu() will
+ * eventually return the value true.
+ */
+unsigned long start_poll_synchronize_srcu(struct srcu_struct *ssp)
+{
+	unsigned long ret = get_state_synchronize_srcu(ssp);
+
+	srcu_gp_start_if_needed(ssp);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(start_poll_synchronize_srcu);
+
+/*
+ * poll_state_synchronize_srcu - Has cookie's grace period ended?
+ */
+bool poll_state_synchronize_srcu(struct srcu_struct *ssp, unsigned long cookie)
+{
+	unsigned long cur_s = READ_ONCE(ssp->srcu_idx);
+
+	barrier();
+	return ULONG_CMP_GE(cur_s, cookie) || ULONG_CMP_LT(cur_s, cookie - 3);
+}
+EXPORT_SYMBOL_GPL(poll_state_synchronize_srcu);
+
+/* Lockdep diagnostics.  */
+void __init rcu_scheduler_starting(void)
+{
+	rcu_scheduler_active = RCU_SCHEDULER_RUNNING;
+}
+
+/*
+ * Queue work for srcu_struct structures with early boot callbacks.
+ * The work won't actually execute until the workqueue initialization
+ * phase that takes place after the scheduler starts.
+ */
+void __init srcu_init(void)
+{
+	struct srcu_struct *ssp;
+
+	srcu_init_done = true;
+	while (!list_empty(&srcu_boot_list)) {
+		ssp = list_first_entry(&srcu_boot_list,
+				      struct srcu_struct, srcu_work.entry);
+		list_del_init(&ssp->srcu_work.entry);
+		schedule_work(&ssp->srcu_work);
+	}
+}
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
new file mode 100644
index 000000000..929dcbc04
--- /dev/null
+++ b/kernel/rcu/srcutree.c
@@ -0,0 +1,1853 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Sleepable Read-Copy Update mechanism for mutual exclusion.
+ *
+ * Copyright (C) IBM Corporation, 2006
+ * Copyright (C) Fujitsu, 2012
+ *
+ * Authors: Paul McKenney <paulmck@linux.ibm.com>
+ *	   Lai Jiangshan <laijs@cn.fujitsu.com>
+ *
+ * For detailed explanation of Read-Copy Update mechanism see -
+ *		Documentation/RCU/ *.txt
+ *
+ */
+
+#define pr_fmt(fmt) "rcu: " fmt
+
+#include <linux/export.h>
+#include <linux/mutex.h>
+#include <linux/percpu.h>
+#include <linux/preempt.h>
+#include <linux/rcupdate_wait.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/srcu.h>
+
+#include "rcu.h"
+#include "rcu_segcblist.h"
+
+/* Holdoff in nanoseconds for auto-expediting. */
+#define DEFAULT_SRCU_EXP_HOLDOFF (25 * 1000)
+static ulong exp_holdoff = DEFAULT_SRCU_EXP_HOLDOFF;
+module_param(exp_holdoff, ulong, 0444);
+
+/* Overflow-check frequency.  N bits roughly says every 2**N grace periods. */
+static ulong counter_wrap_check = (ULONG_MAX >> 2);
+module_param(counter_wrap_check, ulong, 0444);
+
+/*
+ * Control conversion to SRCU_SIZE_BIG:
+ *    0: Don't convert at all.
+ *    1: Convert at init_srcu_struct() time.
+ *    2: Convert when rcutorture invokes srcu_torture_stats_print().
+ *    3: Decide at boot time based on system shape (default).
+ * 0x1x: Convert when excessive contention encountered.
+ */
+#define SRCU_SIZING_NONE	0
+#define SRCU_SIZING_INIT	1
+#define SRCU_SIZING_TORTURE	2
+#define SRCU_SIZING_AUTO	3
+#define SRCU_SIZING_CONTEND	0x10
+#define SRCU_SIZING_IS(x) ((convert_to_big & ~SRCU_SIZING_CONTEND) == x)
+#define SRCU_SIZING_IS_NONE() (SRCU_SIZING_IS(SRCU_SIZING_NONE))
+#define SRCU_SIZING_IS_INIT() (SRCU_SIZING_IS(SRCU_SIZING_INIT))
+#define SRCU_SIZING_IS_TORTURE() (SRCU_SIZING_IS(SRCU_SIZING_TORTURE))
+#define SRCU_SIZING_IS_CONTEND() (convert_to_big & SRCU_SIZING_CONTEND)
+static int convert_to_big = SRCU_SIZING_AUTO;
+module_param(convert_to_big, int, 0444);
+
+/* Number of CPUs to trigger init_srcu_struct()-time transition to big. */
+static int big_cpu_lim __read_mostly = 128;
+module_param(big_cpu_lim, int, 0444);
+
+/* Contention events per jiffy to initiate transition to big. */
+static int small_contention_lim __read_mostly = 100;
+module_param(small_contention_lim, int, 0444);
+
+/* Early-boot callback-management, so early that no lock is required! */
+static LIST_HEAD(srcu_boot_list);
+static bool __read_mostly srcu_init_done;
+
+static void srcu_invoke_callbacks(struct work_struct *work);
+static void srcu_reschedule(struct srcu_struct *ssp, unsigned long delay);
+static void process_srcu(struct work_struct *work);
+static void srcu_delay_timer(struct timer_list *t);
+
+/* Wrappers for lock acquisition and release, see raw_spin_lock_rcu_node(). */
+#define spin_lock_rcu_node(p)							\
+do {										\
+	spin_lock(&ACCESS_PRIVATE(p, lock));					\
+	smp_mb__after_unlock_lock();						\
+} while (0)
+
+#define spin_unlock_rcu_node(p) spin_unlock(&ACCESS_PRIVATE(p, lock))
+
+#define spin_lock_irq_rcu_node(p)						\
+do {										\
+	spin_lock_irq(&ACCESS_PRIVATE(p, lock));				\
+	smp_mb__after_unlock_lock();						\
+} while (0)
+
+#define spin_unlock_irq_rcu_node(p)						\
+	spin_unlock_irq(&ACCESS_PRIVATE(p, lock))
+
+#define spin_lock_irqsave_rcu_node(p, flags)					\
+do {										\
+	spin_lock_irqsave(&ACCESS_PRIVATE(p, lock), flags);			\
+	smp_mb__after_unlock_lock();						\
+} while (0)
+
+#define spin_trylock_irqsave_rcu_node(p, flags)					\
+({										\
+	bool ___locked = spin_trylock_irqsave(&ACCESS_PRIVATE(p, lock), flags);	\
+										\
+	if (___locked)								\
+		smp_mb__after_unlock_lock();					\
+	___locked;								\
+})
+
+#define spin_unlock_irqrestore_rcu_node(p, flags)				\
+	spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags)			\
+
+/*
+ * Initialize SRCU per-CPU data.  Note that statically allocated
+ * srcu_struct structures might already have srcu_read_lock() and
+ * srcu_read_unlock() running against them.  So if the is_static parameter
+ * is set, don't initialize ->srcu_lock_count[] and ->srcu_unlock_count[].
+ */
+static void init_srcu_struct_data(struct srcu_struct *ssp)
+{
+	int cpu;
+	struct srcu_data *sdp;
+
+	/*
+	 * Initialize the per-CPU srcu_data array, which feeds into the
+	 * leaves of the srcu_node tree.
+	 */
+	WARN_ON_ONCE(ARRAY_SIZE(sdp->srcu_lock_count) !=
+		     ARRAY_SIZE(sdp->srcu_unlock_count));
+	for_each_possible_cpu(cpu) {
+		sdp = per_cpu_ptr(ssp->sda, cpu);
+		spin_lock_init(&ACCESS_PRIVATE(sdp, lock));
+		rcu_segcblist_init(&sdp->srcu_cblist);
+		sdp->srcu_cblist_invoking = false;
+		sdp->srcu_gp_seq_needed = ssp->srcu_gp_seq;
+		sdp->srcu_gp_seq_needed_exp = ssp->srcu_gp_seq;
+		sdp->mynode = NULL;
+		sdp->cpu = cpu;
+		INIT_WORK(&sdp->work, srcu_invoke_callbacks);
+		timer_setup(&sdp->delay_work, srcu_delay_timer, 0);
+		sdp->ssp = ssp;
+	}
+}
+
+/* Invalid seq state, used during snp node initialization */
+#define SRCU_SNP_INIT_SEQ		0x2
+
+/*
+ * Check whether sequence number corresponding to snp node,
+ * is invalid.
+ */
+static inline bool srcu_invl_snp_seq(unsigned long s)
+{
+	return rcu_seq_state(s) == SRCU_SNP_INIT_SEQ;
+}
+
+/*
+ * Allocated and initialize SRCU combining tree.  Returns @true if
+ * allocation succeeded and @false otherwise.
+ */
+static bool init_srcu_struct_nodes(struct srcu_struct *ssp, gfp_t gfp_flags)
+{
+	int cpu;
+	int i;
+	int level = 0;
+	int levelspread[RCU_NUM_LVLS];
+	struct srcu_data *sdp;
+	struct srcu_node *snp;
+	struct srcu_node *snp_first;
+
+	/* Initialize geometry if it has not already been initialized. */
+	rcu_init_geometry();
+	ssp->node = kcalloc(rcu_num_nodes, sizeof(*ssp->node), gfp_flags);
+	if (!ssp->node)
+		return false;
+
+	/* Work out the overall tree geometry. */
+	ssp->level[0] = &ssp->node[0];
+	for (i = 1; i < rcu_num_lvls; i++)
+		ssp->level[i] = ssp->level[i - 1] + num_rcu_lvl[i - 1];
+	rcu_init_levelspread(levelspread, num_rcu_lvl);
+
+	/* Each pass through this loop initializes one srcu_node structure. */
+	srcu_for_each_node_breadth_first(ssp, snp) {
+		spin_lock_init(&ACCESS_PRIVATE(snp, lock));
+		WARN_ON_ONCE(ARRAY_SIZE(snp->srcu_have_cbs) !=
+			     ARRAY_SIZE(snp->srcu_data_have_cbs));
+		for (i = 0; i < ARRAY_SIZE(snp->srcu_have_cbs); i++) {
+			snp->srcu_have_cbs[i] = SRCU_SNP_INIT_SEQ;
+			snp->srcu_data_have_cbs[i] = 0;
+		}
+		snp->srcu_gp_seq_needed_exp = SRCU_SNP_INIT_SEQ;
+		snp->grplo = -1;
+		snp->grphi = -1;
+		if (snp == &ssp->node[0]) {
+			/* Root node, special case. */
+			snp->srcu_parent = NULL;
+			continue;
+		}
+
+		/* Non-root node. */
+		if (snp == ssp->level[level + 1])
+			level++;
+		snp->srcu_parent = ssp->level[level - 1] +
+				   (snp - ssp->level[level]) /
+				   levelspread[level - 1];
+	}
+
+	/*
+	 * Initialize the per-CPU srcu_data array, which feeds into the
+	 * leaves of the srcu_node tree.
+	 */
+	level = rcu_num_lvls - 1;
+	snp_first = ssp->level[level];
+	for_each_possible_cpu(cpu) {
+		sdp = per_cpu_ptr(ssp->sda, cpu);
+		sdp->mynode = &snp_first[cpu / levelspread[level]];
+		for (snp = sdp->mynode; snp != NULL; snp = snp->srcu_parent) {
+			if (snp->grplo < 0)
+				snp->grplo = cpu;
+			snp->grphi = cpu;
+		}
+		sdp->grpmask = 1UL << (cpu - sdp->mynode->grplo);
+	}
+	smp_store_release(&ssp->srcu_size_state, SRCU_SIZE_WAIT_BARRIER);
+	return true;
+}
+
+/*
+ * Initialize non-compile-time initialized fields, including the
+ * associated srcu_node and srcu_data structures.  The is_static parameter
+ * tells us that ->sda has already been wired up to srcu_data.
+ */
+static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
+{
+	ssp->srcu_size_state = SRCU_SIZE_SMALL;
+	ssp->node = NULL;
+	mutex_init(&ssp->srcu_cb_mutex);
+	mutex_init(&ssp->srcu_gp_mutex);
+	ssp->srcu_idx = 0;
+	ssp->srcu_gp_seq = 0;
+	ssp->srcu_barrier_seq = 0;
+	mutex_init(&ssp->srcu_barrier_mutex);
+	atomic_set(&ssp->srcu_barrier_cpu_cnt, 0);
+	INIT_DELAYED_WORK(&ssp->work, process_srcu);
+	ssp->sda_is_static = is_static;
+	if (!is_static)
+		ssp->sda = alloc_percpu(struct srcu_data);
+	if (!ssp->sda)
+		return -ENOMEM;
+	init_srcu_struct_data(ssp);
+	ssp->srcu_gp_seq_needed_exp = 0;
+	ssp->srcu_last_gp_end = ktime_get_mono_fast_ns();
+	if (READ_ONCE(ssp->srcu_size_state) == SRCU_SIZE_SMALL && SRCU_SIZING_IS_INIT()) {
+		if (!init_srcu_struct_nodes(ssp, GFP_ATOMIC)) {
+			if (!ssp->sda_is_static) {
+				free_percpu(ssp->sda);
+				ssp->sda = NULL;
+				return -ENOMEM;
+			}
+		} else {
+			WRITE_ONCE(ssp->srcu_size_state, SRCU_SIZE_BIG);
+		}
+	}
+	smp_store_release(&ssp->srcu_gp_seq_needed, 0); /* Init done. */
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
+int __init_srcu_struct(struct srcu_struct *ssp, const char *name,
+		       struct lock_class_key *key)
+{
+	/* Don't re-initialize a lock while it is held. */
+	debug_check_no_locks_freed((void *)ssp, sizeof(*ssp));
+	lockdep_init_map(&ssp->dep_map, name, key, 0);
+	spin_lock_init(&ACCESS_PRIVATE(ssp, lock));
+	return init_srcu_struct_fields(ssp, false);
+}
+EXPORT_SYMBOL_GPL(__init_srcu_struct);
+
+#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
+/**
+ * init_srcu_struct - initialize a sleep-RCU structure
+ * @ssp: structure to initialize.
+ *
+ * Must invoke this on a given srcu_struct before passing that srcu_struct
+ * to any other function.  Each srcu_struct represents a separate domain
+ * of SRCU protection.
+ */
+int init_srcu_struct(struct srcu_struct *ssp)
+{
+	spin_lock_init(&ACCESS_PRIVATE(ssp, lock));
+	return init_srcu_struct_fields(ssp, false);
+}
+EXPORT_SYMBOL_GPL(init_srcu_struct);
+
+#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
+/*
+ * Initiate a transition to SRCU_SIZE_BIG with lock held.
+ */
+static void __srcu_transition_to_big(struct srcu_struct *ssp)
+{
+	lockdep_assert_held(&ACCESS_PRIVATE(ssp, lock));
+	smp_store_release(&ssp->srcu_size_state, SRCU_SIZE_ALLOC);
+}
+
+/*
+ * Initiate an idempotent transition to SRCU_SIZE_BIG.
+ */
+static void srcu_transition_to_big(struct srcu_struct *ssp)
+{
+	unsigned long flags;
+
+	/* Double-checked locking on ->srcu_size-state. */
+	if (smp_load_acquire(&ssp->srcu_size_state) != SRCU_SIZE_SMALL)
+		return;
+	spin_lock_irqsave_rcu_node(ssp, flags);
+	if (smp_load_acquire(&ssp->srcu_size_state) != SRCU_SIZE_SMALL) {
+		spin_unlock_irqrestore_rcu_node(ssp, flags);
+		return;
+	}
+	__srcu_transition_to_big(ssp);
+	spin_unlock_irqrestore_rcu_node(ssp, flags);
+}
+
+/*
+ * Check to see if the just-encountered contention event justifies
+ * a transition to SRCU_SIZE_BIG.
+ */
+static void spin_lock_irqsave_check_contention(struct srcu_struct *ssp)
+{
+	unsigned long j;
+
+	if (!SRCU_SIZING_IS_CONTEND() || ssp->srcu_size_state)
+		return;
+	j = jiffies;
+	if (ssp->srcu_size_jiffies != j) {
+		ssp->srcu_size_jiffies = j;
+		ssp->srcu_n_lock_retries = 0;
+	}
+	if (++ssp->srcu_n_lock_retries <= small_contention_lim)
+		return;
+	__srcu_transition_to_big(ssp);
+}
+
+/*
+ * Acquire the specified srcu_data structure's ->lock, but check for
+ * excessive contention, which results in initiation of a transition
+ * to SRCU_SIZE_BIG.  But only if the srcutree.convert_to_big module
+ * parameter permits this.
+ */
+static void spin_lock_irqsave_sdp_contention(struct srcu_data *sdp, unsigned long *flags)
+{
+	struct srcu_struct *ssp = sdp->ssp;
+
+	if (spin_trylock_irqsave_rcu_node(sdp, *flags))
+		return;
+	spin_lock_irqsave_rcu_node(ssp, *flags);
+	spin_lock_irqsave_check_contention(ssp);
+	spin_unlock_irqrestore_rcu_node(ssp, *flags);
+	spin_lock_irqsave_rcu_node(sdp, *flags);
+}
+
+/*
+ * Acquire the specified srcu_struct structure's ->lock, but check for
+ * excessive contention, which results in initiation of a transition
+ * to SRCU_SIZE_BIG.  But only if the srcutree.convert_to_big module
+ * parameter permits this.
+ */
+static void spin_lock_irqsave_ssp_contention(struct srcu_struct *ssp, unsigned long *flags)
+{
+	if (spin_trylock_irqsave_rcu_node(ssp, *flags))
+		return;
+	spin_lock_irqsave_rcu_node(ssp, *flags);
+	spin_lock_irqsave_check_contention(ssp);
+}
+
+/*
+ * First-use initialization of statically allocated srcu_struct
+ * structure.  Wiring up the combining tree is more than can be
+ * done with compile-time initialization, so this check is added
+ * to each update-side SRCU primitive.  Use ssp->lock, which -is-
+ * compile-time initialized, to resolve races involving multiple
+ * CPUs trying to garner first-use privileges.
+ */
+static void check_init_srcu_struct(struct srcu_struct *ssp)
+{
+	unsigned long flags;
+
+	/* The smp_load_acquire() pairs with the smp_store_release(). */
+	if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_gp_seq_needed))) /*^^^*/
+		return; /* Already initialized. */
+	spin_lock_irqsave_rcu_node(ssp, flags);
+	if (!rcu_seq_state(ssp->srcu_gp_seq_needed)) {
+		spin_unlock_irqrestore_rcu_node(ssp, flags);
+		return;
+	}
+	init_srcu_struct_fields(ssp, true);
+	spin_unlock_irqrestore_rcu_node(ssp, flags);
+}
+
+/*
+ * Returns approximate total of the readers' ->srcu_lock_count[] values
+ * for the rank of per-CPU counters specified by idx.
+ */
+static unsigned long srcu_readers_lock_idx(struct srcu_struct *ssp, int idx)
+{
+	int cpu;
+	unsigned long sum = 0;
+
+	for_each_possible_cpu(cpu) {
+		struct srcu_data *cpuc = per_cpu_ptr(ssp->sda, cpu);
+
+		sum += READ_ONCE(cpuc->srcu_lock_count[idx]);
+	}
+	return sum;
+}
+
+/*
+ * Returns approximate total of the readers' ->srcu_unlock_count[] values
+ * for the rank of per-CPU counters specified by idx.
+ */
+static unsigned long srcu_readers_unlock_idx(struct srcu_struct *ssp, int idx)
+{
+	int cpu;
+	unsigned long sum = 0;
+
+	for_each_possible_cpu(cpu) {
+		struct srcu_data *cpuc = per_cpu_ptr(ssp->sda, cpu);
+
+		sum += READ_ONCE(cpuc->srcu_unlock_count[idx]);
+	}
+	return sum;
+}
+
+/*
+ * Return true if the number of pre-existing readers is determined to
+ * be zero.
+ */
+static bool srcu_readers_active_idx_check(struct srcu_struct *ssp, int idx)
+{
+	unsigned long unlocks;
+
+	unlocks = srcu_readers_unlock_idx(ssp, idx);
+
+	/*
+	 * Make sure that a lock is always counted if the corresponding
+	 * unlock is counted. Needs to be a smp_mb() as the read side may
+	 * contain a read from a variable that is written to before the
+	 * synchronize_srcu() in the write side. In this case smp_mb()s
+	 * A and B act like the store buffering pattern.
+	 *
+	 * This smp_mb() also pairs with smp_mb() C to prevent accesses
+	 * after the synchronize_srcu() from being executed before the
+	 * grace period ends.
+	 */
+	smp_mb(); /* A */
+
+	/*
+	 * If the locks are the same as the unlocks, then there must have
+	 * been no readers on this index at some time in between. This does
+	 * not mean that there are no more readers, as one could have read
+	 * the current index but not have incremented the lock counter yet.
+	 *
+	 * So suppose that the updater is preempted here for so long
+	 * that more than ULONG_MAX non-nested readers come and go in
+	 * the meantime.  It turns out that this cannot result in overflow
+	 * because if a reader modifies its unlock count after we read it
+	 * above, then that reader's next load of ->srcu_idx is guaranteed
+	 * to get the new value, which will cause it to operate on the
+	 * other bank of counters, where it cannot contribute to the
+	 * overflow of these counters.  This means that there is a maximum
+	 * of 2*NR_CPUS increments, which cannot overflow given current
+	 * systems, especially not on 64-bit systems.
+	 *
+	 * OK, how about nesting?  This does impose a limit on nesting
+	 * of floor(ULONG_MAX/NR_CPUS/2), which should be sufficient,
+	 * especially on 64-bit systems.
+	 */
+	return srcu_readers_lock_idx(ssp, idx) == unlocks;
+}
+
+/**
+ * srcu_readers_active - returns true if there are readers. and false
+ *                       otherwise
+ * @ssp: which srcu_struct to count active readers (holding srcu_read_lock).
+ *
+ * Note that this is not an atomic primitive, and can therefore suffer
+ * severe errors when invoked on an active srcu_struct.  That said, it
+ * can be useful as an error check at cleanup time.
+ */
+static bool srcu_readers_active(struct srcu_struct *ssp)
+{
+	int cpu;
+	unsigned long sum = 0;
+
+	for_each_possible_cpu(cpu) {
+		struct srcu_data *cpuc = per_cpu_ptr(ssp->sda, cpu);
+
+		sum += READ_ONCE(cpuc->srcu_lock_count[0]);
+		sum += READ_ONCE(cpuc->srcu_lock_count[1]);
+		sum -= READ_ONCE(cpuc->srcu_unlock_count[0]);
+		sum -= READ_ONCE(cpuc->srcu_unlock_count[1]);
+	}
+	return sum;
+}
+
+/*
+ * We use an adaptive strategy for synchronize_srcu() and especially for
+ * synchronize_srcu_expedited().  We spin for a fixed time period
+ * (defined below, boot time configurable) to allow SRCU readers to exit
+ * their read-side critical sections.  If there are still some readers
+ * after one jiffy, we repeatedly block for one jiffy time periods.
+ * The blocking time is increased as the grace-period age increases,
+ * with max blocking time capped at 10 jiffies.
+ */
+#define SRCU_DEFAULT_RETRY_CHECK_DELAY		5
+
+static ulong srcu_retry_check_delay = SRCU_DEFAULT_RETRY_CHECK_DELAY;
+module_param(srcu_retry_check_delay, ulong, 0444);
+
+#define SRCU_INTERVAL		1		// Base delay if no expedited GPs pending.
+#define SRCU_MAX_INTERVAL	10		// Maximum incremental delay from slow readers.
+
+#define SRCU_DEFAULT_MAX_NODELAY_PHASE_LO	3UL	// Lowmark on default per-GP-phase
+							// no-delay instances.
+#define SRCU_DEFAULT_MAX_NODELAY_PHASE_HI	1000UL	// Highmark on default per-GP-phase
+							// no-delay instances.
+
+#define SRCU_UL_CLAMP_LO(val, low)	((val) > (low) ? (val) : (low))
+#define SRCU_UL_CLAMP_HI(val, high)	((val) < (high) ? (val) : (high))
+#define SRCU_UL_CLAMP(val, low, high)	SRCU_UL_CLAMP_HI(SRCU_UL_CLAMP_LO((val), (low)), (high))
+// per-GP-phase no-delay instances adjusted to allow non-sleeping poll upto
+// one jiffies time duration. Mult by 2 is done to factor in the srcu_get_delay()
+// called from process_srcu().
+#define SRCU_DEFAULT_MAX_NODELAY_PHASE_ADJUSTED	\
+	(2UL * USEC_PER_SEC / HZ / SRCU_DEFAULT_RETRY_CHECK_DELAY)
+
+// Maximum per-GP-phase consecutive no-delay instances.
+#define SRCU_DEFAULT_MAX_NODELAY_PHASE	\
+	SRCU_UL_CLAMP(SRCU_DEFAULT_MAX_NODELAY_PHASE_ADJUSTED,	\
+		      SRCU_DEFAULT_MAX_NODELAY_PHASE_LO,	\
+		      SRCU_DEFAULT_MAX_NODELAY_PHASE_HI)
+
+static ulong srcu_max_nodelay_phase = SRCU_DEFAULT_MAX_NODELAY_PHASE;
+module_param(srcu_max_nodelay_phase, ulong, 0444);
+
+// Maximum consecutive no-delay instances.
+#define SRCU_DEFAULT_MAX_NODELAY	(SRCU_DEFAULT_MAX_NODELAY_PHASE > 100 ?	\
+					 SRCU_DEFAULT_MAX_NODELAY_PHASE : 100)
+
+static ulong srcu_max_nodelay = SRCU_DEFAULT_MAX_NODELAY;
+module_param(srcu_max_nodelay, ulong, 0444);
+
+/*
+ * Return grace-period delay, zero if there are expedited grace
+ * periods pending, SRCU_INTERVAL otherwise.
+ */
+static unsigned long srcu_get_delay(struct srcu_struct *ssp)
+{
+	unsigned long gpstart;
+	unsigned long j;
+	unsigned long jbase = SRCU_INTERVAL;
+
+	if (ULONG_CMP_LT(READ_ONCE(ssp->srcu_gp_seq), READ_ONCE(ssp->srcu_gp_seq_needed_exp)))
+		jbase = 0;
+	if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq))) {
+		j = jiffies - 1;
+		gpstart = READ_ONCE(ssp->srcu_gp_start);
+		if (time_after(j, gpstart))
+			jbase += j - gpstart;
+		if (!jbase) {
+			WRITE_ONCE(ssp->srcu_n_exp_nodelay, READ_ONCE(ssp->srcu_n_exp_nodelay) + 1);
+			if (READ_ONCE(ssp->srcu_n_exp_nodelay) > srcu_max_nodelay_phase)
+				jbase = 1;
+		}
+	}
+	return jbase > SRCU_MAX_INTERVAL ? SRCU_MAX_INTERVAL : jbase;
+}
+
+/**
+ * cleanup_srcu_struct - deconstruct a sleep-RCU structure
+ * @ssp: structure to clean up.
+ *
+ * Must invoke this after you are finished using a given srcu_struct that
+ * was initialized via init_srcu_struct(), else you leak memory.
+ */
+void cleanup_srcu_struct(struct srcu_struct *ssp)
+{
+	int cpu;
+
+	if (WARN_ON(!srcu_get_delay(ssp)))
+		return; /* Just leak it! */
+	if (WARN_ON(srcu_readers_active(ssp)))
+		return; /* Just leak it! */
+	flush_delayed_work(&ssp->work);
+	for_each_possible_cpu(cpu) {
+		struct srcu_data *sdp = per_cpu_ptr(ssp->sda, cpu);
+
+		del_timer_sync(&sdp->delay_work);
+		flush_work(&sdp->work);
+		if (WARN_ON(rcu_segcblist_n_cbs(&sdp->srcu_cblist)))
+			return; /* Forgot srcu_barrier(), so just leak it! */
+	}
+	if (WARN_ON(rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
+	    WARN_ON(rcu_seq_current(&ssp->srcu_gp_seq) != ssp->srcu_gp_seq_needed) ||
+	    WARN_ON(srcu_readers_active(ssp))) {
+		pr_info("%s: Active srcu_struct %p read state: %d gp state: %lu/%lu\n",
+			__func__, ssp, rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)),
+			rcu_seq_current(&ssp->srcu_gp_seq), ssp->srcu_gp_seq_needed);
+		return; /* Caller forgot to stop doing call_srcu()? */
+	}
+	if (!ssp->sda_is_static) {
+		free_percpu(ssp->sda);
+		ssp->sda = NULL;
+	}
+	kfree(ssp->node);
+	ssp->node = NULL;
+	ssp->srcu_size_state = SRCU_SIZE_SMALL;
+}
+EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
+
+/*
+ * Counts the new reader in the appropriate per-CPU element of the
+ * srcu_struct.
+ * Returns an index that must be passed to the matching srcu_read_unlock().
+ */
+int __srcu_read_lock(struct srcu_struct *ssp)
+{
+	int idx;
+
+	idx = READ_ONCE(ssp->srcu_idx) & 0x1;
+	this_cpu_inc(ssp->sda->srcu_lock_count[idx]);
+	smp_mb(); /* B */  /* Avoid leaking the critical section. */
+	return idx;
+}
+EXPORT_SYMBOL_GPL(__srcu_read_lock);
+
+/*
+ * Removes the count for the old reader from the appropriate per-CPU
+ * element of the srcu_struct.  Note that this may well be a different
+ * CPU than that which was incremented by the corresponding srcu_read_lock().
+ */
+void __srcu_read_unlock(struct srcu_struct *ssp, int idx)
+{
+	smp_mb(); /* C */  /* Avoid leaking the critical section. */
+	this_cpu_inc(ssp->sda->srcu_unlock_count[idx]);
+}
+EXPORT_SYMBOL_GPL(__srcu_read_unlock);
+
+/*
+ * Start an SRCU grace period.
+ */
+static void srcu_gp_start(struct srcu_struct *ssp)
+{
+	struct srcu_data *sdp;
+	int state;
+
+	if (smp_load_acquire(&ssp->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER)
+		sdp = per_cpu_ptr(ssp->sda, get_boot_cpu_id());
+	else
+		sdp = this_cpu_ptr(ssp->sda);
+	lockdep_assert_held(&ACCESS_PRIVATE(ssp, lock));
+	WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed));
+	spin_lock_rcu_node(sdp);  /* Interrupts already disabled. */
+	rcu_segcblist_advance(&sdp->srcu_cblist,
+			      rcu_seq_current(&ssp->srcu_gp_seq));
+	(void)rcu_segcblist_accelerate(&sdp->srcu_cblist,
+				       rcu_seq_snap(&ssp->srcu_gp_seq));
+	spin_unlock_rcu_node(sdp);  /* Interrupts remain disabled. */
+	WRITE_ONCE(ssp->srcu_gp_start, jiffies);
+	WRITE_ONCE(ssp->srcu_n_exp_nodelay, 0);
+	smp_mb(); /* Order prior store to ->srcu_gp_seq_needed vs. GP start. */
+	rcu_seq_start(&ssp->srcu_gp_seq);
+	state = rcu_seq_state(ssp->srcu_gp_seq);
+	WARN_ON_ONCE(state != SRCU_STATE_SCAN1);
+}
+
+
+static void srcu_delay_timer(struct timer_list *t)
+{
+	struct srcu_data *sdp = container_of(t, struct srcu_data, delay_work);
+
+	queue_work_on(sdp->cpu, rcu_gp_wq, &sdp->work);
+}
+
+static void srcu_queue_delayed_work_on(struct srcu_data *sdp,
+				       unsigned long delay)
+{
+	if (!delay) {
+		queue_work_on(sdp->cpu, rcu_gp_wq, &sdp->work);
+		return;
+	}
+
+	timer_reduce(&sdp->delay_work, jiffies + delay);
+}
+
+/*
+ * Schedule callback invocation for the specified srcu_data structure,
+ * if possible, on the corresponding CPU.
+ */
+static void srcu_schedule_cbs_sdp(struct srcu_data *sdp, unsigned long delay)
+{
+	srcu_queue_delayed_work_on(sdp, delay);
+}
+
+/*
+ * Schedule callback invocation for all srcu_data structures associated
+ * with the specified srcu_node structure that have callbacks for the
+ * just-completed grace period, the one corresponding to idx.  If possible,
+ * schedule this invocation on the corresponding CPUs.
+ */
+static void srcu_schedule_cbs_snp(struct srcu_struct *ssp, struct srcu_node *snp,
+				  unsigned long mask, unsigned long delay)
+{
+	int cpu;
+
+	for (cpu = snp->grplo; cpu <= snp->grphi; cpu++) {
+		if (!(mask & (1UL << (cpu - snp->grplo))))
+			continue;
+		srcu_schedule_cbs_sdp(per_cpu_ptr(ssp->sda, cpu), delay);
+	}
+}
+
+/*
+ * Note the end of an SRCU grace period.  Initiates callback invocation
+ * and starts a new grace period if needed.
+ *
+ * The ->srcu_cb_mutex acquisition does not protect any data, but
+ * instead prevents more than one grace period from starting while we
+ * are initiating callback invocation.  This allows the ->srcu_have_cbs[]
+ * array to have a finite number of elements.
+ */
+static void srcu_gp_end(struct srcu_struct *ssp)
+{
+	unsigned long cbdelay = 1;
+	bool cbs;
+	bool last_lvl;
+	int cpu;
+	unsigned long flags;
+	unsigned long gpseq;
+	int idx;
+	unsigned long mask;
+	struct srcu_data *sdp;
+	unsigned long sgsne;
+	struct srcu_node *snp;
+	int ss_state;
+
+	/* Prevent more than one additional grace period. */
+	mutex_lock(&ssp->srcu_cb_mutex);
+
+	/* End the current grace period. */
+	spin_lock_irq_rcu_node(ssp);
+	idx = rcu_seq_state(ssp->srcu_gp_seq);
+	WARN_ON_ONCE(idx != SRCU_STATE_SCAN2);
+	if (ULONG_CMP_LT(READ_ONCE(ssp->srcu_gp_seq), READ_ONCE(ssp->srcu_gp_seq_needed_exp)))
+		cbdelay = 0;
+
+	WRITE_ONCE(ssp->srcu_last_gp_end, ktime_get_mono_fast_ns());
+	rcu_seq_end(&ssp->srcu_gp_seq);
+	gpseq = rcu_seq_current(&ssp->srcu_gp_seq);
+	if (ULONG_CMP_LT(ssp->srcu_gp_seq_needed_exp, gpseq))
+		WRITE_ONCE(ssp->srcu_gp_seq_needed_exp, gpseq);
+	spin_unlock_irq_rcu_node(ssp);
+	mutex_unlock(&ssp->srcu_gp_mutex);
+	/* A new grace period can start at this point.  But only one. */
+
+	/* Initiate callback invocation as needed. */
+	ss_state = smp_load_acquire(&ssp->srcu_size_state);
+	if (ss_state < SRCU_SIZE_WAIT_BARRIER) {
+		srcu_schedule_cbs_sdp(per_cpu_ptr(ssp->sda, get_boot_cpu_id()),
+					cbdelay);
+	} else {
+		idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs);
+		srcu_for_each_node_breadth_first(ssp, snp) {
+			spin_lock_irq_rcu_node(snp);
+			cbs = false;
+			last_lvl = snp >= ssp->level[rcu_num_lvls - 1];
+			if (last_lvl)
+				cbs = ss_state < SRCU_SIZE_BIG || snp->srcu_have_cbs[idx] == gpseq;
+			snp->srcu_have_cbs[idx] = gpseq;
+			rcu_seq_set_state(&snp->srcu_have_cbs[idx], 1);
+			sgsne = snp->srcu_gp_seq_needed_exp;
+			if (srcu_invl_snp_seq(sgsne) || ULONG_CMP_LT(sgsne, gpseq))
+				WRITE_ONCE(snp->srcu_gp_seq_needed_exp, gpseq);
+			if (ss_state < SRCU_SIZE_BIG)
+				mask = ~0;
+			else
+				mask = snp->srcu_data_have_cbs[idx];
+			snp->srcu_data_have_cbs[idx] = 0;
+			spin_unlock_irq_rcu_node(snp);
+			if (cbs)
+				srcu_schedule_cbs_snp(ssp, snp, mask, cbdelay);
+		}
+	}
+
+	/* Occasionally prevent srcu_data counter wrap. */
+	if (!(gpseq & counter_wrap_check))
+		for_each_possible_cpu(cpu) {
+			sdp = per_cpu_ptr(ssp->sda, cpu);
+			spin_lock_irqsave_rcu_node(sdp, flags);
+			if (ULONG_CMP_GE(gpseq, sdp->srcu_gp_seq_needed + 100))
+				sdp->srcu_gp_seq_needed = gpseq;
+			if (ULONG_CMP_GE(gpseq, sdp->srcu_gp_seq_needed_exp + 100))
+				sdp->srcu_gp_seq_needed_exp = gpseq;
+			spin_unlock_irqrestore_rcu_node(sdp, flags);
+		}
+
+	/* Callback initiation done, allow grace periods after next. */
+	mutex_unlock(&ssp->srcu_cb_mutex);
+
+	/* Start a new grace period if needed. */
+	spin_lock_irq_rcu_node(ssp);
+	gpseq = rcu_seq_current(&ssp->srcu_gp_seq);
+	if (!rcu_seq_state(gpseq) &&
+	    ULONG_CMP_LT(gpseq, ssp->srcu_gp_seq_needed)) {
+		srcu_gp_start(ssp);
+		spin_unlock_irq_rcu_node(ssp);
+		srcu_reschedule(ssp, 0);
+	} else {
+		spin_unlock_irq_rcu_node(ssp);
+	}
+
+	/* Transition to big if needed. */
+	if (ss_state != SRCU_SIZE_SMALL && ss_state != SRCU_SIZE_BIG) {
+		if (ss_state == SRCU_SIZE_ALLOC)
+			init_srcu_struct_nodes(ssp, GFP_KERNEL);
+		else
+			smp_store_release(&ssp->srcu_size_state, ss_state + 1);
+	}
+}
+
+/*
+ * Funnel-locking scheme to scalably mediate many concurrent expedited
+ * grace-period requests.  This function is invoked for the first known
+ * expedited request for a grace period that has already been requested,
+ * but without expediting.  To start a completely new grace period,
+ * whether expedited or not, use srcu_funnel_gp_start() instead.
+ */
+static void srcu_funnel_exp_start(struct srcu_struct *ssp, struct srcu_node *snp,
+				  unsigned long s)
+{
+	unsigned long flags;
+	unsigned long sgsne;
+
+	if (snp)
+		for (; snp != NULL; snp = snp->srcu_parent) {
+			sgsne = READ_ONCE(snp->srcu_gp_seq_needed_exp);
+			if (rcu_seq_done(&ssp->srcu_gp_seq, s) ||
+			    (!srcu_invl_snp_seq(sgsne) && ULONG_CMP_GE(sgsne, s)))
+				return;
+			spin_lock_irqsave_rcu_node(snp, flags);
+			sgsne = snp->srcu_gp_seq_needed_exp;
+			if (!srcu_invl_snp_seq(sgsne) && ULONG_CMP_GE(sgsne, s)) {
+				spin_unlock_irqrestore_rcu_node(snp, flags);
+				return;
+			}
+			WRITE_ONCE(snp->srcu_gp_seq_needed_exp, s);
+			spin_unlock_irqrestore_rcu_node(snp, flags);
+		}
+	spin_lock_irqsave_ssp_contention(ssp, &flags);
+	if (ULONG_CMP_LT(ssp->srcu_gp_seq_needed_exp, s))
+		WRITE_ONCE(ssp->srcu_gp_seq_needed_exp, s);
+	spin_unlock_irqrestore_rcu_node(ssp, flags);
+}
+
+/*
+ * Funnel-locking scheme to scalably mediate many concurrent grace-period
+ * requests.  The winner has to do the work of actually starting grace
+ * period s.  Losers must either ensure that their desired grace-period
+ * number is recorded on at least their leaf srcu_node structure, or they
+ * must take steps to invoke their own callbacks.
+ *
+ * Note that this function also does the work of srcu_funnel_exp_start(),
+ * in some cases by directly invoking it.
+ */
+static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp,
+				 unsigned long s, bool do_norm)
+{
+	unsigned long flags;
+	int idx = rcu_seq_ctr(s) % ARRAY_SIZE(sdp->mynode->srcu_have_cbs);
+	unsigned long sgsne;
+	struct srcu_node *snp;
+	struct srcu_node *snp_leaf;
+	unsigned long snp_seq;
+
+	/* Ensure that snp node tree is fully initialized before traversing it */
+	if (smp_load_acquire(&ssp->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER)
+		snp_leaf = NULL;
+	else
+		snp_leaf = sdp->mynode;
+
+	if (snp_leaf)
+		/* Each pass through the loop does one level of the srcu_node tree. */
+		for (snp = snp_leaf; snp != NULL; snp = snp->srcu_parent) {
+			if (rcu_seq_done(&ssp->srcu_gp_seq, s) && snp != snp_leaf)
+				return; /* GP already done and CBs recorded. */
+			spin_lock_irqsave_rcu_node(snp, flags);
+			snp_seq = snp->srcu_have_cbs[idx];
+			if (!srcu_invl_snp_seq(snp_seq) && ULONG_CMP_GE(snp_seq, s)) {
+				if (snp == snp_leaf && snp_seq == s)
+					snp->srcu_data_have_cbs[idx] |= sdp->grpmask;
+				spin_unlock_irqrestore_rcu_node(snp, flags);
+				if (snp == snp_leaf && snp_seq != s) {
+					srcu_schedule_cbs_sdp(sdp, do_norm ? SRCU_INTERVAL : 0);
+					return;
+				}
+				if (!do_norm)
+					srcu_funnel_exp_start(ssp, snp, s);
+				return;
+			}
+			snp->srcu_have_cbs[idx] = s;
+			if (snp == snp_leaf)
+				snp->srcu_data_have_cbs[idx] |= sdp->grpmask;
+			sgsne = snp->srcu_gp_seq_needed_exp;
+			if (!do_norm && (srcu_invl_snp_seq(sgsne) || ULONG_CMP_LT(sgsne, s)))
+				WRITE_ONCE(snp->srcu_gp_seq_needed_exp, s);
+			spin_unlock_irqrestore_rcu_node(snp, flags);
+		}
+
+	/* Top of tree, must ensure the grace period will be started. */
+	spin_lock_irqsave_ssp_contention(ssp, &flags);
+	if (ULONG_CMP_LT(ssp->srcu_gp_seq_needed, s)) {
+		/*
+		 * Record need for grace period s.  Pair with load
+		 * acquire setting up for initialization.
+		 */
+		smp_store_release(&ssp->srcu_gp_seq_needed, s); /*^^^*/
+	}
+	if (!do_norm && ULONG_CMP_LT(ssp->srcu_gp_seq_needed_exp, s))
+		WRITE_ONCE(ssp->srcu_gp_seq_needed_exp, s);
+
+	/* If grace period not already done and none in progress, start it. */
+	if (!rcu_seq_done(&ssp->srcu_gp_seq, s) &&
+	    rcu_seq_state(ssp->srcu_gp_seq) == SRCU_STATE_IDLE) {
+		WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed));
+		srcu_gp_start(ssp);
+
+		// And how can that list_add() in the "else" clause
+		// possibly be safe for concurrent execution?  Well,
+		// it isn't.  And it does not have to be.  After all, it
+		// can only be executed during early boot when there is only
+		// the one boot CPU running with interrupts still disabled.
+		if (likely(srcu_init_done))
+			queue_delayed_work(rcu_gp_wq, &ssp->work,
+					   !!srcu_get_delay(ssp));
+		else if (list_empty(&ssp->work.work.entry))
+			list_add(&ssp->work.work.entry, &srcu_boot_list);
+	}
+	spin_unlock_irqrestore_rcu_node(ssp, flags);
+}
+
+/*
+ * Wait until all readers counted by array index idx complete, but
+ * loop an additional time if there is an expedited grace period pending.
+ * The caller must ensure that ->srcu_idx is not changed while checking.
+ */
+static bool try_check_zero(struct srcu_struct *ssp, int idx, int trycount)
+{
+	unsigned long curdelay;
+
+	curdelay = !srcu_get_delay(ssp);
+
+	for (;;) {
+		if (srcu_readers_active_idx_check(ssp, idx))
+			return true;
+		if ((--trycount + curdelay) <= 0)
+			return false;
+		udelay(srcu_retry_check_delay);
+	}
+}
+
+/*
+ * Increment the ->srcu_idx counter so that future SRCU readers will
+ * use the other rank of the ->srcu_(un)lock_count[] arrays.  This allows
+ * us to wait for pre-existing readers in a starvation-free manner.
+ */
+static void srcu_flip(struct srcu_struct *ssp)
+{
+	/*
+	 * Ensure that if this updater saw a given reader's increment
+	 * from __srcu_read_lock(), that reader was using an old value
+	 * of ->srcu_idx.  Also ensure that if a given reader sees the
+	 * new value of ->srcu_idx, this updater's earlier scans cannot
+	 * have seen that reader's increments (which is OK, because this
+	 * grace period need not wait on that reader).
+	 */
+	smp_mb(); /* E */  /* Pairs with B and C. */
+
+	WRITE_ONCE(ssp->srcu_idx, ssp->srcu_idx + 1);
+
+	/*
+	 * Ensure that if the updater misses an __srcu_read_unlock()
+	 * increment, that task's next __srcu_read_lock() will see the
+	 * above counter update.  Note that both this memory barrier
+	 * and the one in srcu_readers_active_idx_check() provide the
+	 * guarantee for __srcu_read_lock().
+	 */
+	smp_mb(); /* D */  /* Pairs with C. */
+}
+
+/*
+ * If SRCU is likely idle, return true, otherwise return false.
+ *
+ * Note that it is OK for several current from-idle requests for a new
+ * grace period from idle to specify expediting because they will all end
+ * up requesting the same grace period anyhow.  So no loss.
+ *
+ * Note also that if any CPU (including the current one) is still invoking
+ * callbacks, this function will nevertheless say "idle".  This is not
+ * ideal, but the overhead of checking all CPUs' callback lists is even
+ * less ideal, especially on large systems.  Furthermore, the wakeup
+ * can happen before the callback is fully removed, so we have no choice
+ * but to accept this type of error.
+ *
+ * This function is also subject to counter-wrap errors, but let's face
+ * it, if this function was preempted for enough time for the counters
+ * to wrap, it really doesn't matter whether or not we expedite the grace
+ * period.  The extra overhead of a needlessly expedited grace period is
+ * negligible when amortized over that time period, and the extra latency
+ * of a needlessly non-expedited grace period is similarly negligible.
+ */
+static bool srcu_might_be_idle(struct srcu_struct *ssp)
+{
+	unsigned long curseq;
+	unsigned long flags;
+	struct srcu_data *sdp;
+	unsigned long t;
+	unsigned long tlast;
+
+	check_init_srcu_struct(ssp);
+	/* If the local srcu_data structure has callbacks, not idle.  */
+	sdp = raw_cpu_ptr(ssp->sda);
+	spin_lock_irqsave_rcu_node(sdp, flags);
+	if (rcu_segcblist_pend_cbs(&sdp->srcu_cblist)) {
+		spin_unlock_irqrestore_rcu_node(sdp, flags);
+		return false; /* Callbacks already present, so not idle. */
+	}
+	spin_unlock_irqrestore_rcu_node(sdp, flags);
+
+	/*
+	 * No local callbacks, so probabilistically probe global state.
+	 * Exact information would require acquiring locks, which would
+	 * kill scalability, hence the probabilistic nature of the probe.
+	 */
+
+	/* First, see if enough time has passed since the last GP. */
+	t = ktime_get_mono_fast_ns();
+	tlast = READ_ONCE(ssp->srcu_last_gp_end);
+	if (exp_holdoff == 0 ||
+	    time_in_range_open(t, tlast, tlast + exp_holdoff))
+		return false; /* Too soon after last GP. */
+
+	/* Next, check for probable idleness. */
+	curseq = rcu_seq_current(&ssp->srcu_gp_seq);
+	smp_mb(); /* Order ->srcu_gp_seq with ->srcu_gp_seq_needed. */
+	if (ULONG_CMP_LT(curseq, READ_ONCE(ssp->srcu_gp_seq_needed)))
+		return false; /* Grace period in progress, so not idle. */
+	smp_mb(); /* Order ->srcu_gp_seq with prior access. */
+	if (curseq != rcu_seq_current(&ssp->srcu_gp_seq))
+		return false; /* GP # changed, so not idle. */
+	return true; /* With reasonable probability, idle! */
+}
+
+/*
+ * SRCU callback function to leak a callback.
+ */
+static void srcu_leak_callback(struct rcu_head *rhp)
+{
+}
+
+/*
+ * Start an SRCU grace period, and also queue the callback if non-NULL.
+ */
+static unsigned long srcu_gp_start_if_needed(struct srcu_struct *ssp,
+					     struct rcu_head *rhp, bool do_norm)
+{
+	unsigned long flags;
+	int idx;
+	bool needexp = false;
+	bool needgp = false;
+	unsigned long s;
+	struct srcu_data *sdp;
+	struct srcu_node *sdp_mynode;
+	int ss_state;
+
+	check_init_srcu_struct(ssp);
+	idx = srcu_read_lock(ssp);
+	ss_state = smp_load_acquire(&ssp->srcu_size_state);
+	if (ss_state < SRCU_SIZE_WAIT_CALL)
+		sdp = per_cpu_ptr(ssp->sda, get_boot_cpu_id());
+	else
+		sdp = raw_cpu_ptr(ssp->sda);
+	spin_lock_irqsave_sdp_contention(sdp, &flags);
+	if (rhp)
+		rcu_segcblist_enqueue(&sdp->srcu_cblist, rhp);
+	/*
+	 * The snapshot for acceleration must be taken _before_ the read of the
+	 * current gp sequence used for advancing, otherwise advancing may fail
+	 * and acceleration may then fail too.
+	 *
+	 * This could happen if:
+	 *
+	 *  1) The RCU_WAIT_TAIL segment has callbacks (gp_num = X + 4) and the
+	 *     RCU_NEXT_READY_TAIL also has callbacks (gp_num = X + 8).
+	 *
+	 *  2) The grace period for RCU_WAIT_TAIL is seen as started but not
+	 *     completed so rcu_seq_current() returns X + SRCU_STATE_SCAN1.
+	 *
+	 *  3) This value is passed to rcu_segcblist_advance() which can't move
+	 *     any segment forward and fails.
+	 *
+	 *  4) srcu_gp_start_if_needed() still proceeds with callback acceleration.
+	 *     But then the call to rcu_seq_snap() observes the grace period for the
+	 *     RCU_WAIT_TAIL segment as completed and the subsequent one for the
+	 *     RCU_NEXT_READY_TAIL segment as started (ie: X + 4 + SRCU_STATE_SCAN1)
+	 *     so it returns a snapshot of the next grace period, which is X + 12.
+	 *
+	 *  5) The value of X + 12 is passed to rcu_segcblist_accelerate() but the
+	 *     freshly enqueued callback in RCU_NEXT_TAIL can't move to
+	 *     RCU_NEXT_READY_TAIL which already has callbacks for a previous grace
+	 *     period (gp_num = X + 8). So acceleration fails.
+	 */
+	s = rcu_seq_snap(&ssp->srcu_gp_seq);
+	rcu_segcblist_advance(&sdp->srcu_cblist,
+			      rcu_seq_current(&ssp->srcu_gp_seq));
+	WARN_ON_ONCE(!rcu_segcblist_accelerate(&sdp->srcu_cblist, s) && rhp);
+	if (ULONG_CMP_LT(sdp->srcu_gp_seq_needed, s)) {
+		sdp->srcu_gp_seq_needed = s;
+		needgp = true;
+	}
+	if (!do_norm && ULONG_CMP_LT(sdp->srcu_gp_seq_needed_exp, s)) {
+		sdp->srcu_gp_seq_needed_exp = s;
+		needexp = true;
+	}
+	spin_unlock_irqrestore_rcu_node(sdp, flags);
+
+	/* Ensure that snp node tree is fully initialized before traversing it */
+	if (ss_state < SRCU_SIZE_WAIT_BARRIER)
+		sdp_mynode = NULL;
+	else
+		sdp_mynode = sdp->mynode;
+
+	if (needgp)
+		srcu_funnel_gp_start(ssp, sdp, s, do_norm);
+	else if (needexp)
+		srcu_funnel_exp_start(ssp, sdp_mynode, s);
+	srcu_read_unlock(ssp, idx);
+	return s;
+}
+
+/*
+ * Enqueue an SRCU callback on the srcu_data structure associated with
+ * the current CPU and the specified srcu_struct structure, initiating
+ * grace-period processing if it is not already running.
+ *
+ * Note that all CPUs must agree that the grace period extended beyond
+ * all pre-existing SRCU read-side critical section.  On systems with
+ * more than one CPU, this means that when "func()" is invoked, each CPU
+ * is guaranteed to have executed a full memory barrier since the end of
+ * its last corresponding SRCU read-side critical section whose beginning
+ * preceded the call to call_srcu().  It also means that each CPU executing
+ * an SRCU read-side critical section that continues beyond the start of
+ * "func()" must have executed a memory barrier after the call_srcu()
+ * but before the beginning of that SRCU read-side critical section.
+ * Note that these guarantees include CPUs that are offline, idle, or
+ * executing in user mode, as well as CPUs that are executing in the kernel.
+ *
+ * Furthermore, if CPU A invoked call_srcu() and CPU B invoked the
+ * resulting SRCU callback function "func()", then both CPU A and CPU
+ * B are guaranteed to execute a full memory barrier during the time
+ * interval between the call to call_srcu() and the invocation of "func()".
+ * This guarantee applies even if CPU A and CPU B are the same CPU (but
+ * again only if the system has more than one CPU).
+ *
+ * Of course, these guarantees apply only for invocations of call_srcu(),
+ * srcu_read_lock(), and srcu_read_unlock() that are all passed the same
+ * srcu_struct structure.
+ */
+static void __call_srcu(struct srcu_struct *ssp, struct rcu_head *rhp,
+			rcu_callback_t func, bool do_norm)
+{
+	if (debug_rcu_head_queue(rhp)) {
+		/* Probable double call_srcu(), so leak the callback. */
+		WRITE_ONCE(rhp->func, srcu_leak_callback);
+		WARN_ONCE(1, "call_srcu(): Leaked duplicate callback\n");
+		return;
+	}
+	rhp->func = func;
+	(void)srcu_gp_start_if_needed(ssp, rhp, do_norm);
+}
+
+/**
+ * call_srcu() - Queue a callback for invocation after an SRCU grace period
+ * @ssp: srcu_struct in queue the callback
+ * @rhp: structure to be used for queueing the SRCU callback.
+ * @func: function to be invoked after the SRCU grace period
+ *
+ * The callback function will be invoked some time after a full SRCU
+ * grace period elapses, in other words after all pre-existing SRCU
+ * read-side critical sections have completed.  However, the callback
+ * function might well execute concurrently with other SRCU read-side
+ * critical sections that started after call_srcu() was invoked.  SRCU
+ * read-side critical sections are delimited by srcu_read_lock() and
+ * srcu_read_unlock(), and may be nested.
+ *
+ * The callback will be invoked from process context, but must nevertheless
+ * be fast and must not block.
+ */
+void call_srcu(struct srcu_struct *ssp, struct rcu_head *rhp,
+	       rcu_callback_t func)
+{
+	__call_srcu(ssp, rhp, func, true);
+}
+EXPORT_SYMBOL_GPL(call_srcu);
+
+/*
+ * Helper function for synchronize_srcu() and synchronize_srcu_expedited().
+ */
+static void __synchronize_srcu(struct srcu_struct *ssp, bool do_norm)
+{
+	struct rcu_synchronize rcu;
+
+	RCU_LOCKDEP_WARN(lockdep_is_held(ssp) ||
+			 lock_is_held(&rcu_bh_lock_map) ||
+			 lock_is_held(&rcu_lock_map) ||
+			 lock_is_held(&rcu_sched_lock_map),
+			 "Illegal synchronize_srcu() in same-type SRCU (or in RCU) read-side critical section");
+
+	if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
+		return;
+	might_sleep();
+	check_init_srcu_struct(ssp);
+	init_completion(&rcu.completion);
+	init_rcu_head_on_stack(&rcu.head);
+	__call_srcu(ssp, &rcu.head, wakeme_after_rcu, do_norm);
+	wait_for_completion(&rcu.completion);
+	destroy_rcu_head_on_stack(&rcu.head);
+
+	/*
+	 * Make sure that later code is ordered after the SRCU grace
+	 * period.  This pairs with the spin_lock_irq_rcu_node()
+	 * in srcu_invoke_callbacks().  Unlike Tree RCU, this is needed
+	 * because the current CPU might have been totally uninvolved with
+	 * (and thus unordered against) that grace period.
+	 */
+	smp_mb();
+}
+
+/**
+ * synchronize_srcu_expedited - Brute-force SRCU grace period
+ * @ssp: srcu_struct with which to synchronize.
+ *
+ * Wait for an SRCU grace period to elapse, but be more aggressive about
+ * spinning rather than blocking when waiting.
+ *
+ * Note that synchronize_srcu_expedited() has the same deadlock and
+ * memory-ordering properties as does synchronize_srcu().
+ */
+void synchronize_srcu_expedited(struct srcu_struct *ssp)
+{
+	__synchronize_srcu(ssp, rcu_gp_is_normal());
+}
+EXPORT_SYMBOL_GPL(synchronize_srcu_expedited);
+
+/**
+ * synchronize_srcu - wait for prior SRCU read-side critical-section completion
+ * @ssp: srcu_struct with which to synchronize.
+ *
+ * Wait for the count to drain to zero of both indexes. To avoid the
+ * possible starvation of synchronize_srcu(), it waits for the count of
+ * the index=((->srcu_idx & 1) ^ 1) to drain to zero at first,
+ * and then flip the srcu_idx and wait for the count of the other index.
+ *
+ * Can block; must be called from process context.
+ *
+ * Note that it is illegal to call synchronize_srcu() from the corresponding
+ * SRCU read-side critical section; doing so will result in deadlock.
+ * However, it is perfectly legal to call synchronize_srcu() on one
+ * srcu_struct from some other srcu_struct's read-side critical section,
+ * as long as the resulting graph of srcu_structs is acyclic.
+ *
+ * There are memory-ordering constraints implied by synchronize_srcu().
+ * On systems with more than one CPU, when synchronize_srcu() returns,
+ * each CPU is guaranteed to have executed a full memory barrier since
+ * the end of its last corresponding SRCU read-side critical section
+ * whose beginning preceded the call to synchronize_srcu().  In addition,
+ * each CPU having an SRCU read-side critical section that extends beyond
+ * the return from synchronize_srcu() is guaranteed to have executed a
+ * full memory barrier after the beginning of synchronize_srcu() and before
+ * the beginning of that SRCU read-side critical section.  Note that these
+ * guarantees include CPUs that are offline, idle, or executing in user mode,
+ * as well as CPUs that are executing in the kernel.
+ *
+ * Furthermore, if CPU A invoked synchronize_srcu(), which returned
+ * to its caller on CPU B, then both CPU A and CPU B are guaranteed
+ * to have executed a full memory barrier during the execution of
+ * synchronize_srcu().  This guarantee applies even if CPU A and CPU B
+ * are the same CPU, but again only if the system has more than one CPU.
+ *
+ * Of course, these memory-ordering guarantees apply only when
+ * synchronize_srcu(), srcu_read_lock(), and srcu_read_unlock() are
+ * passed the same srcu_struct structure.
+ *
+ * Implementation of these memory-ordering guarantees is similar to
+ * that of synchronize_rcu().
+ *
+ * If SRCU is likely idle, expedite the first request.  This semantic
+ * was provided by Classic SRCU, and is relied upon by its users, so TREE
+ * SRCU must also provide it.  Note that detecting idleness is heuristic
+ * and subject to both false positives and negatives.
+ */
+void synchronize_srcu(struct srcu_struct *ssp)
+{
+	if (srcu_might_be_idle(ssp) || rcu_gp_is_expedited())
+		synchronize_srcu_expedited(ssp);
+	else
+		__synchronize_srcu(ssp, true);
+}
+EXPORT_SYMBOL_GPL(synchronize_srcu);
+
+/**
+ * get_state_synchronize_srcu - Provide an end-of-grace-period cookie
+ * @ssp: srcu_struct to provide cookie for.
+ *
+ * This function returns a cookie that can be passed to
+ * poll_state_synchronize_srcu(), which will return true if a full grace
+ * period has elapsed in the meantime.  It is the caller's responsibility
+ * to make sure that grace period happens, for example, by invoking
+ * call_srcu() after return from get_state_synchronize_srcu().
+ */
+unsigned long get_state_synchronize_srcu(struct srcu_struct *ssp)
+{
+	// Any prior manipulation of SRCU-protected data must happen
+	// before the load from ->srcu_gp_seq.
+	smp_mb();
+	return rcu_seq_snap(&ssp->srcu_gp_seq);
+}
+EXPORT_SYMBOL_GPL(get_state_synchronize_srcu);
+
+/**
+ * start_poll_synchronize_srcu - Provide cookie and start grace period
+ * @ssp: srcu_struct to provide cookie for.
+ *
+ * This function returns a cookie that can be passed to
+ * poll_state_synchronize_srcu(), which will return true if a full grace
+ * period has elapsed in the meantime.  Unlike get_state_synchronize_srcu(),
+ * this function also ensures that any needed SRCU grace period will be
+ * started.  This convenience does come at a cost in terms of CPU overhead.
+ */
+unsigned long start_poll_synchronize_srcu(struct srcu_struct *ssp)
+{
+	return srcu_gp_start_if_needed(ssp, NULL, true);
+}
+EXPORT_SYMBOL_GPL(start_poll_synchronize_srcu);
+
+/**
+ * poll_state_synchronize_srcu - Has cookie's grace period ended?
+ * @ssp: srcu_struct to provide cookie for.
+ * @cookie: Return value from get_state_synchronize_srcu() or start_poll_synchronize_srcu().
+ *
+ * This function takes the cookie that was returned from either
+ * get_state_synchronize_srcu() or start_poll_synchronize_srcu(), and
+ * returns @true if an SRCU grace period elapsed since the time that the
+ * cookie was created.
+ *
+ * Because cookies are finite in size, wrapping/overflow is possible.
+ * This is more pronounced on 32-bit systems where cookies are 32 bits,
+ * where in theory wrapping could happen in about 14 hours assuming
+ * 25-microsecond expedited SRCU grace periods.  However, a more likely
+ * overflow lower bound is on the order of 24 days in the case of
+ * one-millisecond SRCU grace periods.  Of course, wrapping in a 64-bit
+ * system requires geologic timespans, as in more than seven million years
+ * even for expedited SRCU grace periods.
+ *
+ * Wrapping/overflow is much more of an issue for CONFIG_SMP=n systems
+ * that also have CONFIG_PREEMPTION=n, which selects Tiny SRCU.  This uses
+ * a 16-bit cookie, which rcutorture routinely wraps in a matter of a
+ * few minutes.  If this proves to be a problem, this counter will be
+ * expanded to the same size as for Tree SRCU.
+ */
+bool poll_state_synchronize_srcu(struct srcu_struct *ssp, unsigned long cookie)
+{
+	if (!rcu_seq_done(&ssp->srcu_gp_seq, cookie))
+		return false;
+	// Ensure that the end of the SRCU grace period happens before
+	// any subsequent code that the caller might execute.
+	smp_mb(); // ^^^
+	return true;
+}
+EXPORT_SYMBOL_GPL(poll_state_synchronize_srcu);
+
+/*
+ * Callback function for srcu_barrier() use.
+ */
+static void srcu_barrier_cb(struct rcu_head *rhp)
+{
+	struct srcu_data *sdp;
+	struct srcu_struct *ssp;
+
+	sdp = container_of(rhp, struct srcu_data, srcu_barrier_head);
+	ssp = sdp->ssp;
+	if (atomic_dec_and_test(&ssp->srcu_barrier_cpu_cnt))
+		complete(&ssp->srcu_barrier_completion);
+}
+
+/*
+ * Enqueue an srcu_barrier() callback on the specified srcu_data
+ * structure's ->cblist.  but only if that ->cblist already has at least one
+ * callback enqueued.  Note that if a CPU already has callbacks enqueue,
+ * it must have already registered the need for a future grace period,
+ * so all we need do is enqueue a callback that will use the same grace
+ * period as the last callback already in the queue.
+ */
+static void srcu_barrier_one_cpu(struct srcu_struct *ssp, struct srcu_data *sdp)
+{
+	spin_lock_irq_rcu_node(sdp);
+	atomic_inc(&ssp->srcu_barrier_cpu_cnt);
+	sdp->srcu_barrier_head.func = srcu_barrier_cb;
+	debug_rcu_head_queue(&sdp->srcu_barrier_head);
+	if (!rcu_segcblist_entrain(&sdp->srcu_cblist,
+				   &sdp->srcu_barrier_head)) {
+		debug_rcu_head_unqueue(&sdp->srcu_barrier_head);
+		atomic_dec(&ssp->srcu_barrier_cpu_cnt);
+	}
+	spin_unlock_irq_rcu_node(sdp);
+}
+
+/**
+ * srcu_barrier - Wait until all in-flight call_srcu() callbacks complete.
+ * @ssp: srcu_struct on which to wait for in-flight callbacks.
+ */
+void srcu_barrier(struct srcu_struct *ssp)
+{
+	int cpu;
+	int idx;
+	unsigned long s = rcu_seq_snap(&ssp->srcu_barrier_seq);
+
+	check_init_srcu_struct(ssp);
+	mutex_lock(&ssp->srcu_barrier_mutex);
+	if (rcu_seq_done(&ssp->srcu_barrier_seq, s)) {
+		smp_mb(); /* Force ordering following return. */
+		mutex_unlock(&ssp->srcu_barrier_mutex);
+		return; /* Someone else did our work for us. */
+	}
+	rcu_seq_start(&ssp->srcu_barrier_seq);
+	init_completion(&ssp->srcu_barrier_completion);
+
+	/* Initial count prevents reaching zero until all CBs are posted. */
+	atomic_set(&ssp->srcu_barrier_cpu_cnt, 1);
+
+	idx = srcu_read_lock(ssp);
+	if (smp_load_acquire(&ssp->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER)
+		srcu_barrier_one_cpu(ssp, per_cpu_ptr(ssp->sda,	get_boot_cpu_id()));
+	else
+		for_each_possible_cpu(cpu)
+			srcu_barrier_one_cpu(ssp, per_cpu_ptr(ssp->sda, cpu));
+	srcu_read_unlock(ssp, idx);
+
+	/* Remove the initial count, at which point reaching zero can happen. */
+	if (atomic_dec_and_test(&ssp->srcu_barrier_cpu_cnt))
+		complete(&ssp->srcu_barrier_completion);
+	wait_for_completion(&ssp->srcu_barrier_completion);
+
+	rcu_seq_end(&ssp->srcu_barrier_seq);
+	mutex_unlock(&ssp->srcu_barrier_mutex);
+}
+EXPORT_SYMBOL_GPL(srcu_barrier);
+
+/**
+ * srcu_batches_completed - return batches completed.
+ * @ssp: srcu_struct on which to report batch completion.
+ *
+ * Report the number of batches, correlated with, but not necessarily
+ * precisely the same as, the number of grace periods that have elapsed.
+ */
+unsigned long srcu_batches_completed(struct srcu_struct *ssp)
+{
+	return READ_ONCE(ssp->srcu_idx);
+}
+EXPORT_SYMBOL_GPL(srcu_batches_completed);
+
+/*
+ * Core SRCU state machine.  Push state bits of ->srcu_gp_seq
+ * to SRCU_STATE_SCAN2, and invoke srcu_gp_end() when scan has
+ * completed in that state.
+ */
+static void srcu_advance_state(struct srcu_struct *ssp)
+{
+	int idx;
+
+	mutex_lock(&ssp->srcu_gp_mutex);
+
+	/*
+	 * Because readers might be delayed for an extended period after
+	 * fetching ->srcu_idx for their index, at any point in time there
+	 * might well be readers using both idx=0 and idx=1.  We therefore
+	 * need to wait for readers to clear from both index values before
+	 * invoking a callback.
+	 *
+	 * The load-acquire ensures that we see the accesses performed
+	 * by the prior grace period.
+	 */
+	idx = rcu_seq_state(smp_load_acquire(&ssp->srcu_gp_seq)); /* ^^^ */
+	if (idx == SRCU_STATE_IDLE) {
+		spin_lock_irq_rcu_node(ssp);
+		if (ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed)) {
+			WARN_ON_ONCE(rcu_seq_state(ssp->srcu_gp_seq));
+			spin_unlock_irq_rcu_node(ssp);
+			mutex_unlock(&ssp->srcu_gp_mutex);
+			return;
+		}
+		idx = rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq));
+		if (idx == SRCU_STATE_IDLE)
+			srcu_gp_start(ssp);
+		spin_unlock_irq_rcu_node(ssp);
+		if (idx != SRCU_STATE_IDLE) {
+			mutex_unlock(&ssp->srcu_gp_mutex);
+			return; /* Someone else started the grace period. */
+		}
+	}
+
+	if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) == SRCU_STATE_SCAN1) {
+		idx = 1 ^ (ssp->srcu_idx & 1);
+		if (!try_check_zero(ssp, idx, 1)) {
+			mutex_unlock(&ssp->srcu_gp_mutex);
+			return; /* readers present, retry later. */
+		}
+		srcu_flip(ssp);
+		spin_lock_irq_rcu_node(ssp);
+		rcu_seq_set_state(&ssp->srcu_gp_seq, SRCU_STATE_SCAN2);
+		ssp->srcu_n_exp_nodelay = 0;
+		spin_unlock_irq_rcu_node(ssp);
+	}
+
+	if (rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) == SRCU_STATE_SCAN2) {
+
+		/*
+		 * SRCU read-side critical sections are normally short,
+		 * so check at least twice in quick succession after a flip.
+		 */
+		idx = 1 ^ (ssp->srcu_idx & 1);
+		if (!try_check_zero(ssp, idx, 2)) {
+			mutex_unlock(&ssp->srcu_gp_mutex);
+			return; /* readers present, retry later. */
+		}
+		ssp->srcu_n_exp_nodelay = 0;
+		srcu_gp_end(ssp);  /* Releases ->srcu_gp_mutex. */
+	}
+}
+
+/*
+ * Invoke a limited number of SRCU callbacks that have passed through
+ * their grace period.  If there are more to do, SRCU will reschedule
+ * the workqueue.  Note that needed memory barriers have been executed
+ * in this task's context by srcu_readers_active_idx_check().
+ */
+static void srcu_invoke_callbacks(struct work_struct *work)
+{
+	long len;
+	bool more;
+	struct rcu_cblist ready_cbs;
+	struct rcu_head *rhp;
+	struct srcu_data *sdp;
+	struct srcu_struct *ssp;
+
+	sdp = container_of(work, struct srcu_data, work);
+
+	ssp = sdp->ssp;
+	rcu_cblist_init(&ready_cbs);
+	spin_lock_irq_rcu_node(sdp);
+	rcu_segcblist_advance(&sdp->srcu_cblist,
+			      rcu_seq_current(&ssp->srcu_gp_seq));
+	if (sdp->srcu_cblist_invoking ||
+	    !rcu_segcblist_ready_cbs(&sdp->srcu_cblist)) {
+		spin_unlock_irq_rcu_node(sdp);
+		return;  /* Someone else on the job or nothing to do. */
+	}
+
+	/* We are on the job!  Extract and invoke ready callbacks. */
+	sdp->srcu_cblist_invoking = true;
+	rcu_segcblist_extract_done_cbs(&sdp->srcu_cblist, &ready_cbs);
+	len = ready_cbs.len;
+	spin_unlock_irq_rcu_node(sdp);
+	rhp = rcu_cblist_dequeue(&ready_cbs);
+	for (; rhp != NULL; rhp = rcu_cblist_dequeue(&ready_cbs)) {
+		debug_rcu_head_unqueue(rhp);
+		local_bh_disable();
+		rhp->func(rhp);
+		local_bh_enable();
+	}
+	WARN_ON_ONCE(ready_cbs.len);
+
+	/*
+	 * Update counts, accelerate new callbacks, and if needed,
+	 * schedule another round of callback invocation.
+	 */
+	spin_lock_irq_rcu_node(sdp);
+	rcu_segcblist_add_len(&sdp->srcu_cblist, -len);
+	(void)rcu_segcblist_accelerate(&sdp->srcu_cblist,
+				       rcu_seq_snap(&ssp->srcu_gp_seq));
+	sdp->srcu_cblist_invoking = false;
+	more = rcu_segcblist_ready_cbs(&sdp->srcu_cblist);
+	spin_unlock_irq_rcu_node(sdp);
+	if (more)
+		srcu_schedule_cbs_sdp(sdp, 0);
+}
+
+/*
+ * Finished one round of SRCU grace period.  Start another if there are
+ * more SRCU callbacks queued, otherwise put SRCU into not-running state.
+ */
+static void srcu_reschedule(struct srcu_struct *ssp, unsigned long delay)
+{
+	bool pushgp = true;
+
+	spin_lock_irq_rcu_node(ssp);
+	if (ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed)) {
+		if (!WARN_ON_ONCE(rcu_seq_state(ssp->srcu_gp_seq))) {
+			/* All requests fulfilled, time to go idle. */
+			pushgp = false;
+		}
+	} else if (!rcu_seq_state(ssp->srcu_gp_seq)) {
+		/* Outstanding request and no GP.  Start one. */
+		srcu_gp_start(ssp);
+	}
+	spin_unlock_irq_rcu_node(ssp);
+
+	if (pushgp)
+		queue_delayed_work(rcu_gp_wq, &ssp->work, delay);
+}
+
+/*
+ * This is the work-queue function that handles SRCU grace periods.
+ */
+static void process_srcu(struct work_struct *work)
+{
+	unsigned long curdelay;
+	unsigned long j;
+	struct srcu_struct *ssp;
+
+	ssp = container_of(work, struct srcu_struct, work.work);
+
+	srcu_advance_state(ssp);
+	curdelay = srcu_get_delay(ssp);
+	if (curdelay) {
+		WRITE_ONCE(ssp->reschedule_count, 0);
+	} else {
+		j = jiffies;
+		if (READ_ONCE(ssp->reschedule_jiffies) == j) {
+			WRITE_ONCE(ssp->reschedule_count, READ_ONCE(ssp->reschedule_count) + 1);
+			if (READ_ONCE(ssp->reschedule_count) > srcu_max_nodelay)
+				curdelay = 1;
+		} else {
+			WRITE_ONCE(ssp->reschedule_count, 1);
+			WRITE_ONCE(ssp->reschedule_jiffies, j);
+		}
+	}
+	srcu_reschedule(ssp, curdelay);
+}
+
+void srcutorture_get_gp_data(enum rcutorture_type test_type,
+			     struct srcu_struct *ssp, int *flags,
+			     unsigned long *gp_seq)
+{
+	if (test_type != SRCU_FLAVOR)
+		return;
+	*flags = 0;
+	*gp_seq = rcu_seq_current(&ssp->srcu_gp_seq);
+}
+EXPORT_SYMBOL_GPL(srcutorture_get_gp_data);
+
+static const char * const srcu_size_state_name[] = {
+	"SRCU_SIZE_SMALL",
+	"SRCU_SIZE_ALLOC",
+	"SRCU_SIZE_WAIT_BARRIER",
+	"SRCU_SIZE_WAIT_CALL",
+	"SRCU_SIZE_WAIT_CBS1",
+	"SRCU_SIZE_WAIT_CBS2",
+	"SRCU_SIZE_WAIT_CBS3",
+	"SRCU_SIZE_WAIT_CBS4",
+	"SRCU_SIZE_BIG",
+	"SRCU_SIZE_???",
+};
+
+void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf)
+{
+	int cpu;
+	int idx;
+	unsigned long s0 = 0, s1 = 0;
+	int ss_state = READ_ONCE(ssp->srcu_size_state);
+	int ss_state_idx = ss_state;
+
+	idx = ssp->srcu_idx & 0x1;
+	if (ss_state < 0 || ss_state >= ARRAY_SIZE(srcu_size_state_name))
+		ss_state_idx = ARRAY_SIZE(srcu_size_state_name) - 1;
+	pr_alert("%s%s Tree SRCU g%ld state %d (%s)",
+		 tt, tf, rcu_seq_current(&ssp->srcu_gp_seq), ss_state,
+		 srcu_size_state_name[ss_state_idx]);
+	if (!ssp->sda) {
+		// Called after cleanup_srcu_struct(), perhaps.
+		pr_cont(" No per-CPU srcu_data structures (->sda == NULL).\n");
+	} else {
+		pr_cont(" per-CPU(idx=%d):", idx);
+		for_each_possible_cpu(cpu) {
+			unsigned long l0, l1;
+			unsigned long u0, u1;
+			long c0, c1;
+			struct srcu_data *sdp;
+
+			sdp = per_cpu_ptr(ssp->sda, cpu);
+			u0 = data_race(sdp->srcu_unlock_count[!idx]);
+			u1 = data_race(sdp->srcu_unlock_count[idx]);
+
+			/*
+			 * Make sure that a lock is always counted if the corresponding
+			 * unlock is counted.
+			 */
+			smp_rmb();
+
+			l0 = data_race(sdp->srcu_lock_count[!idx]);
+			l1 = data_race(sdp->srcu_lock_count[idx]);
+
+			c0 = l0 - u0;
+			c1 = l1 - u1;
+			pr_cont(" %d(%ld,%ld %c)",
+				cpu, c0, c1,
+				"C."[rcu_segcblist_empty(&sdp->srcu_cblist)]);
+			s0 += c0;
+			s1 += c1;
+		}
+		pr_cont(" T(%ld,%ld)\n", s0, s1);
+	}
+	if (SRCU_SIZING_IS_TORTURE())
+		srcu_transition_to_big(ssp);
+}
+EXPORT_SYMBOL_GPL(srcu_torture_stats_print);
+
+static int __init srcu_bootup_announce(void)
+{
+	pr_info("Hierarchical SRCU implementation.\n");
+	if (exp_holdoff != DEFAULT_SRCU_EXP_HOLDOFF)
+		pr_info("\tNon-default auto-expedite holdoff of %lu ns.\n", exp_holdoff);
+	if (srcu_retry_check_delay != SRCU_DEFAULT_RETRY_CHECK_DELAY)
+		pr_info("\tNon-default retry check delay of %lu us.\n", srcu_retry_check_delay);
+	if (srcu_max_nodelay != SRCU_DEFAULT_MAX_NODELAY)
+		pr_info("\tNon-default max no-delay of %lu.\n", srcu_max_nodelay);
+	pr_info("\tMax phase no-delay instances is %lu.\n", srcu_max_nodelay_phase);
+	return 0;
+}
+early_initcall(srcu_bootup_announce);
+
+void __init srcu_init(void)
+{
+	struct srcu_struct *ssp;
+
+	/* Decide on srcu_struct-size strategy. */
+	if (SRCU_SIZING_IS(SRCU_SIZING_AUTO)) {
+		if (nr_cpu_ids >= big_cpu_lim) {
+			convert_to_big = SRCU_SIZING_INIT; // Don't bother waiting for contention.
+			pr_info("%s: Setting srcu_struct sizes to big.\n", __func__);
+		} else {
+			convert_to_big = SRCU_SIZING_NONE | SRCU_SIZING_CONTEND;
+			pr_info("%s: Setting srcu_struct sizes based on contention.\n", __func__);
+		}
+	}
+
+	/*
+	 * Once that is set, call_srcu() can follow the normal path and
+	 * queue delayed work. This must follow RCU workqueues creation
+	 * and timers initialization.
+	 */
+	srcu_init_done = true;
+	while (!list_empty(&srcu_boot_list)) {
+		ssp = list_first_entry(&srcu_boot_list, struct srcu_struct,
+				      work.work.entry);
+		list_del_init(&ssp->work.work.entry);
+		if (SRCU_SIZING_IS(SRCU_SIZING_INIT) && ssp->srcu_size_state == SRCU_SIZE_SMALL)
+			ssp->srcu_size_state = SRCU_SIZE_ALLOC;
+		queue_work(rcu_gp_wq, &ssp->work.work);
+	}
+}
+
+#ifdef CONFIG_MODULES
+
+/* Initialize any global-scope srcu_struct structures used by this module. */
+static int srcu_module_coming(struct module *mod)
+{
+	int i;
+	struct srcu_struct **sspp = mod->srcu_struct_ptrs;
+	int ret;
+
+	for (i = 0; i < mod->num_srcu_structs; i++) {
+		ret = init_srcu_struct(*(sspp++));
+		if (WARN_ON_ONCE(ret))
+			return ret;
+	}
+	return 0;
+}
+
+/* Clean up any global-scope srcu_struct structures used by this module. */
+static void srcu_module_going(struct module *mod)
+{
+	int i;
+	struct srcu_struct **sspp = mod->srcu_struct_ptrs;
+
+	for (i = 0; i < mod->num_srcu_structs; i++)
+		cleanup_srcu_struct(*(sspp++));
+}
+
+/* Handle one module, either coming or going. */
+static int srcu_module_notify(struct notifier_block *self,
+			      unsigned long val, void *data)
+{
+	struct module *mod = data;
+	int ret = 0;
+
+	switch (val) {
+	case MODULE_STATE_COMING:
+		ret = srcu_module_coming(mod);
+		break;
+	case MODULE_STATE_GOING:
+		srcu_module_going(mod);
+		break;
+	default:
+		break;
+	}
+	return ret;
+}
+
+static struct notifier_block srcu_module_nb = {
+	.notifier_call = srcu_module_notify,
+	.priority = 0,
+};
+
+static __init int init_srcu_module_notifier(void)
+{
+	int ret;
+
+	ret = register_module_notifier(&srcu_module_nb);
+	if (ret)
+		pr_warn("Failed to register srcu module notifier\n");
+	return ret;
+}
+late_initcall(init_srcu_module_notifier);
+
+#endif /* #ifdef CONFIG_MODULES */
diff --git a/kernel/rcu/sync.c b/kernel/rcu/sync.c
new file mode 100644
index 000000000..5cefc7021
--- /dev/null
+++ b/kernel/rcu/sync.c
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * RCU-based infrastructure for lightweight reader-writer locking
+ *
+ * Copyright (c) 2015, Red Hat, Inc.
+ *
+ * Author: Oleg Nesterov <oleg@redhat.com>
+ */
+
+#include <linux/rcu_sync.h>
+#include <linux/sched.h>
+
+enum { GP_IDLE = 0, GP_ENTER, GP_PASSED, GP_EXIT, GP_REPLAY };
+
+#define	rss_lock	gp_wait.lock
+
+/**
+ * rcu_sync_init() - Initialize an rcu_sync structure
+ * @rsp: Pointer to rcu_sync structure to be initialized
+ */
+void rcu_sync_init(struct rcu_sync *rsp)
+{
+	memset(rsp, 0, sizeof(*rsp));
+	init_waitqueue_head(&rsp->gp_wait);
+}
+
+/**
+ * rcu_sync_enter_start - Force readers onto slow path for multiple updates
+ * @rsp: Pointer to rcu_sync structure to use for synchronization
+ *
+ * Must be called after rcu_sync_init() and before first use.
+ *
+ * Ensures rcu_sync_is_idle() returns false and rcu_sync_{enter,exit}()
+ * pairs turn into NO-OPs.
+ */
+void rcu_sync_enter_start(struct rcu_sync *rsp)
+{
+	rsp->gp_count++;
+	rsp->gp_state = GP_PASSED;
+}
+
+
+static void rcu_sync_func(struct rcu_head *rhp);
+
+static void rcu_sync_call(struct rcu_sync *rsp)
+{
+	call_rcu(&rsp->cb_head, rcu_sync_func);
+}
+
+/**
+ * rcu_sync_func() - Callback function managing reader access to fastpath
+ * @rhp: Pointer to rcu_head in rcu_sync structure to use for synchronization
+ *
+ * This function is passed to call_rcu() function by rcu_sync_enter() and
+ * rcu_sync_exit(), so that it is invoked after a grace period following the
+ * that invocation of enter/exit.
+ *
+ * If it is called by rcu_sync_enter() it signals that all the readers were
+ * switched onto slow path.
+ *
+ * If it is called by rcu_sync_exit() it takes action based on events that
+ * have taken place in the meantime, so that closely spaced rcu_sync_enter()
+ * and rcu_sync_exit() pairs need not wait for a grace period.
+ *
+ * If another rcu_sync_enter() is invoked before the grace period
+ * ended, reset state to allow the next rcu_sync_exit() to let the
+ * readers back onto their fastpaths (after a grace period).  If both
+ * another rcu_sync_enter() and its matching rcu_sync_exit() are invoked
+ * before the grace period ended, re-invoke call_rcu() on behalf of that
+ * rcu_sync_exit().  Otherwise, set all state back to idle so that readers
+ * can again use their fastpaths.
+ */
+static void rcu_sync_func(struct rcu_head *rhp)
+{
+	struct rcu_sync *rsp = container_of(rhp, struct rcu_sync, cb_head);
+	unsigned long flags;
+
+	WARN_ON_ONCE(READ_ONCE(rsp->gp_state) == GP_IDLE);
+	WARN_ON_ONCE(READ_ONCE(rsp->gp_state) == GP_PASSED);
+
+	spin_lock_irqsave(&rsp->rss_lock, flags);
+	if (rsp->gp_count) {
+		/*
+		 * We're at least a GP after the GP_IDLE->GP_ENTER transition.
+		 */
+		WRITE_ONCE(rsp->gp_state, GP_PASSED);
+		wake_up_locked(&rsp->gp_wait);
+	} else if (rsp->gp_state == GP_REPLAY) {
+		/*
+		 * A new rcu_sync_exit() has happened; requeue the callback to
+		 * catch a later GP.
+		 */
+		WRITE_ONCE(rsp->gp_state, GP_EXIT);
+		rcu_sync_call(rsp);
+	} else {
+		/*
+		 * We're at least a GP after the last rcu_sync_exit(); everybody
+		 * will now have observed the write side critical section.
+		 * Let 'em rip!
+		 */
+		WRITE_ONCE(rsp->gp_state, GP_IDLE);
+	}
+	spin_unlock_irqrestore(&rsp->rss_lock, flags);
+}
+
+/**
+ * rcu_sync_enter() - Force readers onto slowpath
+ * @rsp: Pointer to rcu_sync structure to use for synchronization
+ *
+ * This function is used by updaters who need readers to make use of
+ * a slowpath during the update.  After this function returns, all
+ * subsequent calls to rcu_sync_is_idle() will return false, which
+ * tells readers to stay off their fastpaths.  A later call to
+ * rcu_sync_exit() re-enables reader fastpaths.
+ *
+ * When called in isolation, rcu_sync_enter() must wait for a grace
+ * period, however, closely spaced calls to rcu_sync_enter() can
+ * optimize away the grace-period wait via a state machine implemented
+ * by rcu_sync_enter(), rcu_sync_exit(), and rcu_sync_func().
+ */
+void rcu_sync_enter(struct rcu_sync *rsp)
+{
+	int gp_state;
+
+	spin_lock_irq(&rsp->rss_lock);
+	gp_state = rsp->gp_state;
+	if (gp_state == GP_IDLE) {
+		WRITE_ONCE(rsp->gp_state, GP_ENTER);
+		WARN_ON_ONCE(rsp->gp_count);
+		/*
+		 * Note that we could simply do rcu_sync_call(rsp) here and
+		 * avoid the "if (gp_state == GP_IDLE)" block below.
+		 *
+		 * However, synchronize_rcu() can be faster if rcu_expedited
+		 * or rcu_blocking_is_gp() is true.
+		 *
+		 * Another reason is that we can't wait for rcu callback if
+		 * we are called at early boot time but this shouldn't happen.
+		 */
+	}
+	rsp->gp_count++;
+	spin_unlock_irq(&rsp->rss_lock);
+
+	if (gp_state == GP_IDLE) {
+		/*
+		 * See the comment above, this simply does the "synchronous"
+		 * call_rcu(rcu_sync_func) which does GP_ENTER -> GP_PASSED.
+		 */
+		synchronize_rcu();
+		rcu_sync_func(&rsp->cb_head);
+		/* Not really needed, wait_event() would see GP_PASSED. */
+		return;
+	}
+
+	wait_event(rsp->gp_wait, READ_ONCE(rsp->gp_state) >= GP_PASSED);
+}
+
+/**
+ * rcu_sync_exit() - Allow readers back onto fast path after grace period
+ * @rsp: Pointer to rcu_sync structure to use for synchronization
+ *
+ * This function is used by updaters who have completed, and can therefore
+ * now allow readers to make use of their fastpaths after a grace period
+ * has elapsed.  After this grace period has completed, all subsequent
+ * calls to rcu_sync_is_idle() will return true, which tells readers that
+ * they can once again use their fastpaths.
+ */
+void rcu_sync_exit(struct rcu_sync *rsp)
+{
+	WARN_ON_ONCE(READ_ONCE(rsp->gp_state) == GP_IDLE);
+	WARN_ON_ONCE(READ_ONCE(rsp->gp_count) == 0);
+
+	spin_lock_irq(&rsp->rss_lock);
+	if (!--rsp->gp_count) {
+		if (rsp->gp_state == GP_PASSED) {
+			WRITE_ONCE(rsp->gp_state, GP_EXIT);
+			rcu_sync_call(rsp);
+		} else if (rsp->gp_state == GP_EXIT) {
+			WRITE_ONCE(rsp->gp_state, GP_REPLAY);
+		}
+	}
+	spin_unlock_irq(&rsp->rss_lock);
+}
+
+/**
+ * rcu_sync_dtor() - Clean up an rcu_sync structure
+ * @rsp: Pointer to rcu_sync structure to be cleaned up
+ */
+void rcu_sync_dtor(struct rcu_sync *rsp)
+{
+	int gp_state;
+
+	WARN_ON_ONCE(READ_ONCE(rsp->gp_count));
+	WARN_ON_ONCE(READ_ONCE(rsp->gp_state) == GP_PASSED);
+
+	spin_lock_irq(&rsp->rss_lock);
+	if (rsp->gp_state == GP_REPLAY)
+		WRITE_ONCE(rsp->gp_state, GP_EXIT);
+	gp_state = rsp->gp_state;
+	spin_unlock_irq(&rsp->rss_lock);
+
+	if (gp_state != GP_IDLE) {
+		rcu_barrier();
+		WARN_ON_ONCE(rsp->gp_state != GP_IDLE);
+	}
+}
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
new file mode 100644
index 000000000..b5d5b6cf0
--- /dev/null
+++ b/kernel/rcu/tasks.h
@@ -0,0 +1,1951 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Task-based RCU implementations.
+ *
+ * Copyright (C) 2020 Paul E. McKenney
+ */
+
+#ifdef CONFIG_TASKS_RCU_GENERIC
+#include "rcu_segcblist.h"
+
+////////////////////////////////////////////////////////////////////////
+//
+// Generic data structures.
+
+struct rcu_tasks;
+typedef void (*rcu_tasks_gp_func_t)(struct rcu_tasks *rtp);
+typedef void (*pregp_func_t)(struct list_head *hop);
+typedef void (*pertask_func_t)(struct task_struct *t, struct list_head *hop);
+typedef void (*postscan_func_t)(struct list_head *hop);
+typedef void (*holdouts_func_t)(struct list_head *hop, bool ndrpt, bool *frptp);
+typedef void (*postgp_func_t)(struct rcu_tasks *rtp);
+
+/**
+ * struct rcu_tasks_percpu - Per-CPU component of definition for a Tasks-RCU-like mechanism.
+ * @cblist: Callback list.
+ * @lock: Lock protecting per-CPU callback list.
+ * @rtp_jiffies: Jiffies counter value for statistics.
+ * @rtp_n_lock_retries: Rough lock-contention statistic.
+ * @rtp_work: Work queue for invoking callbacks.
+ * @rtp_irq_work: IRQ work queue for deferred wakeups.
+ * @barrier_q_head: RCU callback for barrier operation.
+ * @rtp_blkd_tasks: List of tasks blocked as readers.
+ * @cpu: CPU number corresponding to this entry.
+ * @rtpp: Pointer to the rcu_tasks structure.
+ */
+struct rcu_tasks_percpu {
+	struct rcu_segcblist cblist;
+	raw_spinlock_t __private lock;
+	unsigned long rtp_jiffies;
+	unsigned long rtp_n_lock_retries;
+	struct work_struct rtp_work;
+	struct irq_work rtp_irq_work;
+	struct rcu_head barrier_q_head;
+	struct list_head rtp_blkd_tasks;
+	int cpu;
+	struct rcu_tasks *rtpp;
+};
+
+/**
+ * struct rcu_tasks - Definition for a Tasks-RCU-like mechanism.
+ * @cbs_wait: RCU wait allowing a new callback to get kthread's attention.
+ * @cbs_gbl_lock: Lock protecting callback list.
+ * @tasks_gp_mutex: Mutex protecting grace period, needed during mid-boot dead zone.
+ * @kthread_ptr: This flavor's grace-period/callback-invocation kthread.
+ * @gp_func: This flavor's grace-period-wait function.
+ * @gp_state: Grace period's most recent state transition (debugging).
+ * @gp_sleep: Per-grace-period sleep to prevent CPU-bound looping.
+ * @init_fract: Initial backoff sleep interval.
+ * @gp_jiffies: Time of last @gp_state transition.
+ * @gp_start: Most recent grace-period start in jiffies.
+ * @tasks_gp_seq: Number of grace periods completed since boot.
+ * @n_ipis: Number of IPIs sent to encourage grace periods to end.
+ * @n_ipis_fails: Number of IPI-send failures.
+ * @pregp_func: This flavor's pre-grace-period function (optional).
+ * @pertask_func: This flavor's per-task scan function (optional).
+ * @postscan_func: This flavor's post-task scan function (optional).
+ * @holdouts_func: This flavor's holdout-list scan function (optional).
+ * @postgp_func: This flavor's post-grace-period function (optional).
+ * @call_func: This flavor's call_rcu()-equivalent function.
+ * @rtpcpu: This flavor's rcu_tasks_percpu structure.
+ * @percpu_enqueue_shift: Shift down CPU ID this much when enqueuing callbacks.
+ * @percpu_enqueue_lim: Number of per-CPU callback queues in use for enqueuing.
+ * @percpu_dequeue_lim: Number of per-CPU callback queues in use for dequeuing.
+ * @percpu_dequeue_gpseq: RCU grace-period number to propagate enqueue limit to dequeuers.
+ * @barrier_q_mutex: Serialize barrier operations.
+ * @barrier_q_count: Number of queues being waited on.
+ * @barrier_q_completion: Barrier wait/wakeup mechanism.
+ * @barrier_q_seq: Sequence number for barrier operations.
+ * @name: This flavor's textual name.
+ * @kname: This flavor's kthread name.
+ */
+struct rcu_tasks {
+	struct rcuwait cbs_wait;
+	raw_spinlock_t cbs_gbl_lock;
+	struct mutex tasks_gp_mutex;
+	int gp_state;
+	int gp_sleep;
+	int init_fract;
+	unsigned long gp_jiffies;
+	unsigned long gp_start;
+	unsigned long tasks_gp_seq;
+	unsigned long n_ipis;
+	unsigned long n_ipis_fails;
+	struct task_struct *kthread_ptr;
+	rcu_tasks_gp_func_t gp_func;
+	pregp_func_t pregp_func;
+	pertask_func_t pertask_func;
+	postscan_func_t postscan_func;
+	holdouts_func_t holdouts_func;
+	postgp_func_t postgp_func;
+	call_rcu_func_t call_func;
+	struct rcu_tasks_percpu __percpu *rtpcpu;
+	int percpu_enqueue_shift;
+	int percpu_enqueue_lim;
+	int percpu_dequeue_lim;
+	unsigned long percpu_dequeue_gpseq;
+	struct mutex barrier_q_mutex;
+	atomic_t barrier_q_count;
+	struct completion barrier_q_completion;
+	unsigned long barrier_q_seq;
+	char *name;
+	char *kname;
+};
+
+static void call_rcu_tasks_iw_wakeup(struct irq_work *iwp);
+
+#define DEFINE_RCU_TASKS(rt_name, gp, call, n)						\
+static DEFINE_PER_CPU(struct rcu_tasks_percpu, rt_name ## __percpu) = {			\
+	.lock = __RAW_SPIN_LOCK_UNLOCKED(rt_name ## __percpu.cbs_pcpu_lock),		\
+	.rtp_irq_work = IRQ_WORK_INIT_HARD(call_rcu_tasks_iw_wakeup),			\
+};											\
+static struct rcu_tasks rt_name =							\
+{											\
+	.cbs_wait = __RCUWAIT_INITIALIZER(rt_name.wait),				\
+	.cbs_gbl_lock = __RAW_SPIN_LOCK_UNLOCKED(rt_name.cbs_gbl_lock),			\
+	.tasks_gp_mutex = __MUTEX_INITIALIZER(rt_name.tasks_gp_mutex),			\
+	.gp_func = gp,									\
+	.call_func = call,								\
+	.rtpcpu = &rt_name ## __percpu,							\
+	.name = n,									\
+	.percpu_enqueue_shift = order_base_2(CONFIG_NR_CPUS),				\
+	.percpu_enqueue_lim = 1,							\
+	.percpu_dequeue_lim = 1,							\
+	.barrier_q_mutex = __MUTEX_INITIALIZER(rt_name.barrier_q_mutex),		\
+	.barrier_q_seq = (0UL - 50UL) << RCU_SEQ_CTR_SHIFT,				\
+	.kname = #rt_name,								\
+}
+
+/* Track exiting tasks in order to allow them to be waited for. */
+DEFINE_STATIC_SRCU(tasks_rcu_exit_srcu);
+
+/* Avoid IPIing CPUs early in the grace period. */
+#define RCU_TASK_IPI_DELAY (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB) ? HZ / 2 : 0)
+static int rcu_task_ipi_delay __read_mostly = RCU_TASK_IPI_DELAY;
+module_param(rcu_task_ipi_delay, int, 0644);
+
+/* Control stall timeouts.  Disable with <= 0, otherwise jiffies till stall. */
+#define RCU_TASK_BOOT_STALL_TIMEOUT (HZ * 30)
+#define RCU_TASK_STALL_TIMEOUT (HZ * 60 * 10)
+static int rcu_task_stall_timeout __read_mostly = RCU_TASK_STALL_TIMEOUT;
+module_param(rcu_task_stall_timeout, int, 0644);
+#define RCU_TASK_STALL_INFO (HZ * 10)
+static int rcu_task_stall_info __read_mostly = RCU_TASK_STALL_INFO;
+module_param(rcu_task_stall_info, int, 0644);
+static int rcu_task_stall_info_mult __read_mostly = 3;
+module_param(rcu_task_stall_info_mult, int, 0444);
+
+static int rcu_task_enqueue_lim __read_mostly = -1;
+module_param(rcu_task_enqueue_lim, int, 0444);
+
+static bool rcu_task_cb_adjust;
+static int rcu_task_contend_lim __read_mostly = 100;
+module_param(rcu_task_contend_lim, int, 0444);
+static int rcu_task_collapse_lim __read_mostly = 10;
+module_param(rcu_task_collapse_lim, int, 0444);
+
+/* RCU tasks grace-period state for debugging. */
+#define RTGS_INIT		 0
+#define RTGS_WAIT_WAIT_CBS	 1
+#define RTGS_WAIT_GP		 2
+#define RTGS_PRE_WAIT_GP	 3
+#define RTGS_SCAN_TASKLIST	 4
+#define RTGS_POST_SCAN_TASKLIST	 5
+#define RTGS_WAIT_SCAN_HOLDOUTS	 6
+#define RTGS_SCAN_HOLDOUTS	 7
+#define RTGS_POST_GP		 8
+#define RTGS_WAIT_READERS	 9
+#define RTGS_INVOKE_CBS		10
+#define RTGS_WAIT_CBS		11
+#ifndef CONFIG_TINY_RCU
+static const char * const rcu_tasks_gp_state_names[] = {
+	"RTGS_INIT",
+	"RTGS_WAIT_WAIT_CBS",
+	"RTGS_WAIT_GP",
+	"RTGS_PRE_WAIT_GP",
+	"RTGS_SCAN_TASKLIST",
+	"RTGS_POST_SCAN_TASKLIST",
+	"RTGS_WAIT_SCAN_HOLDOUTS",
+	"RTGS_SCAN_HOLDOUTS",
+	"RTGS_POST_GP",
+	"RTGS_WAIT_READERS",
+	"RTGS_INVOKE_CBS",
+	"RTGS_WAIT_CBS",
+};
+#endif /* #ifndef CONFIG_TINY_RCU */
+
+////////////////////////////////////////////////////////////////////////
+//
+// Generic code.
+
+static void rcu_tasks_invoke_cbs_wq(struct work_struct *wp);
+
+/* Record grace-period phase and time. */
+static void set_tasks_gp_state(struct rcu_tasks *rtp, int newstate)
+{
+	rtp->gp_state = newstate;
+	rtp->gp_jiffies = jiffies;
+}
+
+#ifndef CONFIG_TINY_RCU
+/* Return state name. */
+static const char *tasks_gp_state_getname(struct rcu_tasks *rtp)
+{
+	int i = data_race(rtp->gp_state); // Let KCSAN detect update races
+	int j = READ_ONCE(i); // Prevent the compiler from reading twice
+
+	if (j >= ARRAY_SIZE(rcu_tasks_gp_state_names))
+		return "???";
+	return rcu_tasks_gp_state_names[j];
+}
+#endif /* #ifndef CONFIG_TINY_RCU */
+
+// Initialize per-CPU callback lists for the specified flavor of
+// Tasks RCU.
+static void cblist_init_generic(struct rcu_tasks *rtp)
+{
+	int cpu;
+	unsigned long flags;
+	int lim;
+	int shift;
+
+	raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);
+	if (rcu_task_enqueue_lim < 0) {
+		rcu_task_enqueue_lim = 1;
+		rcu_task_cb_adjust = true;
+	} else if (rcu_task_enqueue_lim == 0) {
+		rcu_task_enqueue_lim = 1;
+	}
+	lim = rcu_task_enqueue_lim;
+
+	if (lim > nr_cpu_ids)
+		lim = nr_cpu_ids;
+	shift = ilog2(nr_cpu_ids / lim);
+	if (((nr_cpu_ids - 1) >> shift) >= lim)
+		shift++;
+	WRITE_ONCE(rtp->percpu_enqueue_shift, shift);
+	WRITE_ONCE(rtp->percpu_dequeue_lim, lim);
+	smp_store_release(&rtp->percpu_enqueue_lim, lim);
+	for_each_possible_cpu(cpu) {
+		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);
+
+		WARN_ON_ONCE(!rtpcp);
+		if (cpu)
+			raw_spin_lock_init(&ACCESS_PRIVATE(rtpcp, lock));
+		raw_spin_lock_rcu_node(rtpcp); // irqs already disabled.
+		if (rcu_segcblist_empty(&rtpcp->cblist))
+			rcu_segcblist_init(&rtpcp->cblist);
+		INIT_WORK(&rtpcp->rtp_work, rcu_tasks_invoke_cbs_wq);
+		rtpcp->cpu = cpu;
+		rtpcp->rtpp = rtp;
+		if (!rtpcp->rtp_blkd_tasks.next)
+			INIT_LIST_HEAD(&rtpcp->rtp_blkd_tasks);
+		raw_spin_unlock_rcu_node(rtpcp); // irqs remain disabled.
+	}
+	raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);
+
+	if (rcu_task_cb_adjust)
+		pr_info("%s: Setting adjustable number of callback queues.\n", __func__);
+
+	pr_info("%s: Setting shift to %d and lim to %d.\n", __func__, data_race(rtp->percpu_enqueue_shift), data_race(rtp->percpu_enqueue_lim));
+}
+
+// IRQ-work handler that does deferred wakeup for call_rcu_tasks_generic().
+static void call_rcu_tasks_iw_wakeup(struct irq_work *iwp)
+{
+	struct rcu_tasks *rtp;
+	struct rcu_tasks_percpu *rtpcp = container_of(iwp, struct rcu_tasks_percpu, rtp_irq_work);
+
+	rtp = rtpcp->rtpp;
+	rcuwait_wake_up(&rtp->cbs_wait);
+}
+
+// Enqueue a callback for the specified flavor of Tasks RCU.
+static void call_rcu_tasks_generic(struct rcu_head *rhp, rcu_callback_t func,
+				   struct rcu_tasks *rtp)
+{
+	int chosen_cpu;
+	unsigned long flags;
+	int ideal_cpu;
+	unsigned long j;
+	bool needadjust = false;
+	bool needwake;
+	struct rcu_tasks_percpu *rtpcp;
+
+	rhp->next = NULL;
+	rhp->func = func;
+	local_irq_save(flags);
+	rcu_read_lock();
+	ideal_cpu = smp_processor_id() >> READ_ONCE(rtp->percpu_enqueue_shift);
+	chosen_cpu = cpumask_next(ideal_cpu - 1, cpu_possible_mask);
+	rtpcp = per_cpu_ptr(rtp->rtpcpu, chosen_cpu);
+	if (!raw_spin_trylock_rcu_node(rtpcp)) { // irqs already disabled.
+		raw_spin_lock_rcu_node(rtpcp); // irqs already disabled.
+		j = jiffies;
+		if (rtpcp->rtp_jiffies != j) {
+			rtpcp->rtp_jiffies = j;
+			rtpcp->rtp_n_lock_retries = 0;
+		}
+		if (rcu_task_cb_adjust && ++rtpcp->rtp_n_lock_retries > rcu_task_contend_lim &&
+		    READ_ONCE(rtp->percpu_enqueue_lim) != nr_cpu_ids)
+			needadjust = true;  // Defer adjustment to avoid deadlock.
+	}
+	if (!rcu_segcblist_is_enabled(&rtpcp->cblist)) {
+		raw_spin_unlock_rcu_node(rtpcp); // irqs remain disabled.
+		cblist_init_generic(rtp);
+		raw_spin_lock_rcu_node(rtpcp); // irqs already disabled.
+	}
+	needwake = rcu_segcblist_empty(&rtpcp->cblist);
+	rcu_segcblist_enqueue(&rtpcp->cblist, rhp);
+	raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags);
+	if (unlikely(needadjust)) {
+		raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);
+		if (rtp->percpu_enqueue_lim != nr_cpu_ids) {
+			WRITE_ONCE(rtp->percpu_enqueue_shift, 0);
+			WRITE_ONCE(rtp->percpu_dequeue_lim, nr_cpu_ids);
+			smp_store_release(&rtp->percpu_enqueue_lim, nr_cpu_ids);
+			pr_info("Switching %s to per-CPU callback queuing.\n", rtp->name);
+		}
+		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);
+	}
+	rcu_read_unlock();
+	/* We can't create the thread unless interrupts are enabled. */
+	if (needwake && READ_ONCE(rtp->kthread_ptr))
+		irq_work_queue(&rtpcp->rtp_irq_work);
+}
+
+// RCU callback function for rcu_barrier_tasks_generic().
+static void rcu_barrier_tasks_generic_cb(struct rcu_head *rhp)
+{
+	struct rcu_tasks *rtp;
+	struct rcu_tasks_percpu *rtpcp;
+
+	rtpcp = container_of(rhp, struct rcu_tasks_percpu, barrier_q_head);
+	rtp = rtpcp->rtpp;
+	if (atomic_dec_and_test(&rtp->barrier_q_count))
+		complete(&rtp->barrier_q_completion);
+}
+
+// Wait for all in-flight callbacks for the specified RCU Tasks flavor.
+// Operates in a manner similar to rcu_barrier().
+static void rcu_barrier_tasks_generic(struct rcu_tasks *rtp)
+{
+	int cpu;
+	unsigned long flags;
+	struct rcu_tasks_percpu *rtpcp;
+	unsigned long s = rcu_seq_snap(&rtp->barrier_q_seq);
+
+	mutex_lock(&rtp->barrier_q_mutex);
+	if (rcu_seq_done(&rtp->barrier_q_seq, s)) {
+		smp_mb();
+		mutex_unlock(&rtp->barrier_q_mutex);
+		return;
+	}
+	rcu_seq_start(&rtp->barrier_q_seq);
+	init_completion(&rtp->barrier_q_completion);
+	atomic_set(&rtp->barrier_q_count, 2);
+	for_each_possible_cpu(cpu) {
+		if (cpu >= smp_load_acquire(&rtp->percpu_dequeue_lim))
+			break;
+		rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);
+		rtpcp->barrier_q_head.func = rcu_barrier_tasks_generic_cb;
+		raw_spin_lock_irqsave_rcu_node(rtpcp, flags);
+		if (rcu_segcblist_entrain(&rtpcp->cblist, &rtpcp->barrier_q_head))
+			atomic_inc(&rtp->barrier_q_count);
+		raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags);
+	}
+	if (atomic_sub_and_test(2, &rtp->barrier_q_count))
+		complete(&rtp->barrier_q_completion);
+	wait_for_completion(&rtp->barrier_q_completion);
+	rcu_seq_end(&rtp->barrier_q_seq);
+	mutex_unlock(&rtp->barrier_q_mutex);
+}
+
+// Advance callbacks and indicate whether either a grace period or
+// callback invocation is needed.
+static int rcu_tasks_need_gpcb(struct rcu_tasks *rtp)
+{
+	int cpu;
+	unsigned long flags;
+	bool gpdone = poll_state_synchronize_rcu(rtp->percpu_dequeue_gpseq);
+	long n;
+	long ncbs = 0;
+	long ncbsnz = 0;
+	int needgpcb = 0;
+
+	for (cpu = 0; cpu < smp_load_acquire(&rtp->percpu_dequeue_lim); cpu++) {
+		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);
+
+		/* Advance and accelerate any new callbacks. */
+		if (!rcu_segcblist_n_cbs(&rtpcp->cblist))
+			continue;
+		raw_spin_lock_irqsave_rcu_node(rtpcp, flags);
+		// Should we shrink down to a single callback queue?
+		n = rcu_segcblist_n_cbs(&rtpcp->cblist);
+		if (n) {
+			ncbs += n;
+			if (cpu > 0)
+				ncbsnz += n;
+		}
+		rcu_segcblist_advance(&rtpcp->cblist, rcu_seq_current(&rtp->tasks_gp_seq));
+		(void)rcu_segcblist_accelerate(&rtpcp->cblist, rcu_seq_snap(&rtp->tasks_gp_seq));
+		if (rcu_segcblist_pend_cbs(&rtpcp->cblist))
+			needgpcb |= 0x3;
+		if (!rcu_segcblist_empty(&rtpcp->cblist))
+			needgpcb |= 0x1;
+		raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags);
+	}
+
+	// Shrink down to a single callback queue if appropriate.
+	// This is done in two stages: (1) If there are no more than
+	// rcu_task_collapse_lim callbacks on CPU 0 and none on any other
+	// CPU, limit enqueueing to CPU 0.  (2) After an RCU grace period,
+	// if there has not been an increase in callbacks, limit dequeuing
+	// to CPU 0.  Note the matching RCU read-side critical section in
+	// call_rcu_tasks_generic().
+	if (rcu_task_cb_adjust && ncbs <= rcu_task_collapse_lim) {
+		raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);
+		if (rtp->percpu_enqueue_lim > 1) {
+			WRITE_ONCE(rtp->percpu_enqueue_shift, order_base_2(nr_cpu_ids));
+			smp_store_release(&rtp->percpu_enqueue_lim, 1);
+			rtp->percpu_dequeue_gpseq = get_state_synchronize_rcu();
+			gpdone = false;
+			pr_info("Starting switch %s to CPU-0 callback queuing.\n", rtp->name);
+		}
+		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);
+	}
+	if (rcu_task_cb_adjust && !ncbsnz && gpdone) {
+		raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);
+		if (rtp->percpu_enqueue_lim < rtp->percpu_dequeue_lim) {
+			WRITE_ONCE(rtp->percpu_dequeue_lim, 1);
+			pr_info("Completing switch %s to CPU-0 callback queuing.\n", rtp->name);
+		}
+		if (rtp->percpu_dequeue_lim == 1) {
+			for (cpu = rtp->percpu_dequeue_lim; cpu < nr_cpu_ids; cpu++) {
+				struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);
+
+				WARN_ON_ONCE(rcu_segcblist_n_cbs(&rtpcp->cblist));
+			}
+		}
+		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);
+	}
+
+	return needgpcb;
+}
+
+// Advance callbacks and invoke any that are ready.
+static void rcu_tasks_invoke_cbs(struct rcu_tasks *rtp, struct rcu_tasks_percpu *rtpcp)
+{
+	int cpu;
+	int cpunext;
+	int cpuwq;
+	unsigned long flags;
+	int len;
+	struct rcu_head *rhp;
+	struct rcu_cblist rcl = RCU_CBLIST_INITIALIZER(rcl);
+	struct rcu_tasks_percpu *rtpcp_next;
+
+	cpu = rtpcp->cpu;
+	cpunext = cpu * 2 + 1;
+	if (cpunext < smp_load_acquire(&rtp->percpu_dequeue_lim)) {
+		rtpcp_next = per_cpu_ptr(rtp->rtpcpu, cpunext);
+		cpuwq = rcu_cpu_beenfullyonline(cpunext) ? cpunext : WORK_CPU_UNBOUND;
+		queue_work_on(cpuwq, system_wq, &rtpcp_next->rtp_work);
+		cpunext++;
+		if (cpunext < smp_load_acquire(&rtp->percpu_dequeue_lim)) {
+			rtpcp_next = per_cpu_ptr(rtp->rtpcpu, cpunext);
+			cpuwq = rcu_cpu_beenfullyonline(cpunext) ? cpunext : WORK_CPU_UNBOUND;
+			queue_work_on(cpuwq, system_wq, &rtpcp_next->rtp_work);
+		}
+	}
+
+	if (rcu_segcblist_empty(&rtpcp->cblist) || !cpu_possible(cpu))
+		return;
+	raw_spin_lock_irqsave_rcu_node(rtpcp, flags);
+	rcu_segcblist_advance(&rtpcp->cblist, rcu_seq_current(&rtp->tasks_gp_seq));
+	rcu_segcblist_extract_done_cbs(&rtpcp->cblist, &rcl);
+	raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags);
+	len = rcl.len;
+	for (rhp = rcu_cblist_dequeue(&rcl); rhp; rhp = rcu_cblist_dequeue(&rcl)) {
+		local_bh_disable();
+		rhp->func(rhp);
+		local_bh_enable();
+		cond_resched();
+	}
+	raw_spin_lock_irqsave_rcu_node(rtpcp, flags);
+	rcu_segcblist_add_len(&rtpcp->cblist, -len);
+	(void)rcu_segcblist_accelerate(&rtpcp->cblist, rcu_seq_snap(&rtp->tasks_gp_seq));
+	raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags);
+}
+
+// Workqueue flood to advance callbacks and invoke any that are ready.
+static void rcu_tasks_invoke_cbs_wq(struct work_struct *wp)
+{
+	struct rcu_tasks *rtp;
+	struct rcu_tasks_percpu *rtpcp = container_of(wp, struct rcu_tasks_percpu, rtp_work);
+
+	rtp = rtpcp->rtpp;
+	rcu_tasks_invoke_cbs(rtp, rtpcp);
+}
+
+// Wait for one grace period.
+static void rcu_tasks_one_gp(struct rcu_tasks *rtp, bool midboot)
+{
+	int needgpcb;
+
+	mutex_lock(&rtp->tasks_gp_mutex);
+
+	// If there were none, wait a bit and start over.
+	if (unlikely(midboot)) {
+		needgpcb = 0x2;
+	} else {
+		set_tasks_gp_state(rtp, RTGS_WAIT_CBS);
+		rcuwait_wait_event(&rtp->cbs_wait,
+				   (needgpcb = rcu_tasks_need_gpcb(rtp)),
+				   TASK_IDLE);
+	}
+
+	if (needgpcb & 0x2) {
+		// Wait for one grace period.
+		set_tasks_gp_state(rtp, RTGS_WAIT_GP);
+		rtp->gp_start = jiffies;
+		rcu_seq_start(&rtp->tasks_gp_seq);
+		rtp->gp_func(rtp);
+		rcu_seq_end(&rtp->tasks_gp_seq);
+	}
+
+	// Invoke callbacks.
+	set_tasks_gp_state(rtp, RTGS_INVOKE_CBS);
+	rcu_tasks_invoke_cbs(rtp, per_cpu_ptr(rtp->rtpcpu, 0));
+	mutex_unlock(&rtp->tasks_gp_mutex);
+}
+
+// RCU-tasks kthread that detects grace periods and invokes callbacks.
+static int __noreturn rcu_tasks_kthread(void *arg)
+{
+	struct rcu_tasks *rtp = arg;
+
+	/* Run on housekeeping CPUs by default.  Sysadm can move if desired. */
+	housekeeping_affine(current, HK_TYPE_RCU);
+	WRITE_ONCE(rtp->kthread_ptr, current); // Let GPs start!
+
+	/*
+	 * Each pass through the following loop makes one check for
+	 * newly arrived callbacks, and, if there are some, waits for
+	 * one RCU-tasks grace period and then invokes the callbacks.
+	 * This loop is terminated by the system going down.  ;-)
+	 */
+	for (;;) {
+		// Wait for one grace period and invoke any callbacks
+		// that are ready.
+		rcu_tasks_one_gp(rtp, false);
+
+		// Paranoid sleep to keep this from entering a tight loop.
+		schedule_timeout_idle(rtp->gp_sleep);
+	}
+}
+
+// Wait for a grace period for the specified flavor of Tasks RCU.
+static void synchronize_rcu_tasks_generic(struct rcu_tasks *rtp)
+{
+	/* Complain if the scheduler has not started.  */
+	if (WARN_ONCE(rcu_scheduler_active == RCU_SCHEDULER_INACTIVE,
+			 "synchronize_%s() called too soon", rtp->name))
+		return;
+
+	// If the grace-period kthread is running, use it.
+	if (READ_ONCE(rtp->kthread_ptr)) {
+		wait_rcu_gp(rtp->call_func);
+		return;
+	}
+	rcu_tasks_one_gp(rtp, true);
+}
+
+/* Spawn RCU-tasks grace-period kthread. */
+static void __init rcu_spawn_tasks_kthread_generic(struct rcu_tasks *rtp)
+{
+	struct task_struct *t;
+
+	t = kthread_run(rcu_tasks_kthread, rtp, "%s_kthread", rtp->kname);
+	if (WARN_ONCE(IS_ERR(t), "%s: Could not start %s grace-period kthread, OOM is now expected behavior\n", __func__, rtp->name))
+		return;
+	smp_mb(); /* Ensure others see full kthread. */
+}
+
+#ifndef CONFIG_TINY_RCU
+
+/*
+ * Print any non-default Tasks RCU settings.
+ */
+static void __init rcu_tasks_bootup_oddness(void)
+{
+#if defined(CONFIG_TASKS_RCU) || defined(CONFIG_TASKS_TRACE_RCU)
+	int rtsimc;
+
+	if (rcu_task_stall_timeout != RCU_TASK_STALL_TIMEOUT)
+		pr_info("\tTasks-RCU CPU stall warnings timeout set to %d (rcu_task_stall_timeout).\n", rcu_task_stall_timeout);
+	rtsimc = clamp(rcu_task_stall_info_mult, 1, 10);
+	if (rtsimc != rcu_task_stall_info_mult) {
+		pr_info("\tTasks-RCU CPU stall info multiplier clamped to %d (rcu_task_stall_info_mult).\n", rtsimc);
+		rcu_task_stall_info_mult = rtsimc;
+	}
+#endif /* #ifdef CONFIG_TASKS_RCU */
+#ifdef CONFIG_TASKS_RCU
+	pr_info("\tTrampoline variant of Tasks RCU enabled.\n");
+#endif /* #ifdef CONFIG_TASKS_RCU */
+#ifdef CONFIG_TASKS_RUDE_RCU
+	pr_info("\tRude variant of Tasks RCU enabled.\n");
+#endif /* #ifdef CONFIG_TASKS_RUDE_RCU */
+#ifdef CONFIG_TASKS_TRACE_RCU
+	pr_info("\tTracing variant of Tasks RCU enabled.\n");
+#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
+}
+
+#endif /* #ifndef CONFIG_TINY_RCU */
+
+#ifndef CONFIG_TINY_RCU
+/* Dump out rcutorture-relevant state common to all RCU-tasks flavors. */
+static void show_rcu_tasks_generic_gp_kthread(struct rcu_tasks *rtp, char *s)
+{
+	int cpu;
+	bool havecbs = false;
+
+	for_each_possible_cpu(cpu) {
+		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);
+
+		if (!data_race(rcu_segcblist_empty(&rtpcp->cblist))) {
+			havecbs = true;
+			break;
+		}
+	}
+	pr_info("%s: %s(%d) since %lu g:%lu i:%lu/%lu %c%c %s\n",
+		rtp->kname,
+		tasks_gp_state_getname(rtp), data_race(rtp->gp_state),
+		jiffies - data_race(rtp->gp_jiffies),
+		data_race(rcu_seq_current(&rtp->tasks_gp_seq)),
+		data_race(rtp->n_ipis_fails), data_race(rtp->n_ipis),
+		".k"[!!data_race(rtp->kthread_ptr)],
+		".C"[havecbs],
+		s);
+}
+#endif // #ifndef CONFIG_TINY_RCU
+
+static void exit_tasks_rcu_finish_trace(struct task_struct *t);
+
+#if defined(CONFIG_TASKS_RCU) || defined(CONFIG_TASKS_TRACE_RCU)
+
+////////////////////////////////////////////////////////////////////////
+//
+// Shared code between task-list-scanning variants of Tasks RCU.
+
+/* Wait for one RCU-tasks grace period. */
+static void rcu_tasks_wait_gp(struct rcu_tasks *rtp)
+{
+	struct task_struct *g;
+	int fract;
+	LIST_HEAD(holdouts);
+	unsigned long j;
+	unsigned long lastinfo;
+	unsigned long lastreport;
+	bool reported = false;
+	int rtsi;
+	struct task_struct *t;
+
+	set_tasks_gp_state(rtp, RTGS_PRE_WAIT_GP);
+	rtp->pregp_func(&holdouts);
+
+	/*
+	 * There were callbacks, so we need to wait for an RCU-tasks
+	 * grace period.  Start off by scanning the task list for tasks
+	 * that are not already voluntarily blocked.  Mark these tasks
+	 * and make a list of them in holdouts.
+	 */
+	set_tasks_gp_state(rtp, RTGS_SCAN_TASKLIST);
+	if (rtp->pertask_func) {
+		rcu_read_lock();
+		for_each_process_thread(g, t)
+			rtp->pertask_func(t, &holdouts);
+		rcu_read_unlock();
+	}
+
+	set_tasks_gp_state(rtp, RTGS_POST_SCAN_TASKLIST);
+	rtp->postscan_func(&holdouts);
+
+	/*
+	 * Each pass through the following loop scans the list of holdout
+	 * tasks, removing any that are no longer holdouts.  When the list
+	 * is empty, we are done.
+	 */
+	lastreport = jiffies;
+	lastinfo = lastreport;
+	rtsi = READ_ONCE(rcu_task_stall_info);
+
+	// Start off with initial wait and slowly back off to 1 HZ wait.
+	fract = rtp->init_fract;
+
+	while (!list_empty(&holdouts)) {
+		ktime_t exp;
+		bool firstreport;
+		bool needreport;
+		int rtst;
+
+		// Slowly back off waiting for holdouts
+		set_tasks_gp_state(rtp, RTGS_WAIT_SCAN_HOLDOUTS);
+		if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {
+			schedule_timeout_idle(fract);
+		} else {
+			exp = jiffies_to_nsecs(fract);
+			__set_current_state(TASK_IDLE);
+			schedule_hrtimeout_range(&exp, jiffies_to_nsecs(HZ / 2), HRTIMER_MODE_REL_HARD);
+		}
+
+		if (fract < HZ)
+			fract++;
+
+		rtst = READ_ONCE(rcu_task_stall_timeout);
+		needreport = rtst > 0 && time_after(jiffies, lastreport + rtst);
+		if (needreport) {
+			lastreport = jiffies;
+			reported = true;
+		}
+		firstreport = true;
+		WARN_ON(signal_pending(current));
+		set_tasks_gp_state(rtp, RTGS_SCAN_HOLDOUTS);
+		rtp->holdouts_func(&holdouts, needreport, &firstreport);
+
+		// Print pre-stall informational messages if needed.
+		j = jiffies;
+		if (rtsi > 0 && !reported && time_after(j, lastinfo + rtsi)) {
+			lastinfo = j;
+			rtsi = rtsi * rcu_task_stall_info_mult;
+			pr_info("%s: %s grace period %lu is %lu jiffies old.\n",
+				__func__, rtp->kname, rtp->tasks_gp_seq, j - rtp->gp_start);
+		}
+	}
+
+	set_tasks_gp_state(rtp, RTGS_POST_GP);
+	rtp->postgp_func(rtp);
+}
+
+#endif /* #if defined(CONFIG_TASKS_RCU) || defined(CONFIG_TASKS_TRACE_RCU) */
+
+#ifdef CONFIG_TASKS_RCU
+
+////////////////////////////////////////////////////////////////////////
+//
+// Simple variant of RCU whose quiescent states are voluntary context
+// switch, cond_resched_tasks_rcu_qs(), user-space execution, and idle.
+// As such, grace periods can take one good long time.  There are no
+// read-side primitives similar to rcu_read_lock() and rcu_read_unlock()
+// because this implementation is intended to get the system into a safe
+// state for some of the manipulations involved in tracing and the like.
+// Finally, this implementation does not support high call_rcu_tasks()
+// rates from multiple CPUs.  If this is required, per-CPU callback lists
+// will be needed.
+//
+// The implementation uses rcu_tasks_wait_gp(), which relies on function
+// pointers in the rcu_tasks structure.  The rcu_spawn_tasks_kthread()
+// function sets these function pointers up so that rcu_tasks_wait_gp()
+// invokes these functions in this order:
+//
+// rcu_tasks_pregp_step():
+//	Invokes synchronize_rcu() in order to wait for all in-flight
+//	t->on_rq and t->nvcsw transitions to complete.	This works because
+//	all such transitions are carried out with interrupts disabled.
+// rcu_tasks_pertask(), invoked on every non-idle task:
+//	For every runnable non-idle task other than the current one, use
+//	get_task_struct() to pin down that task, snapshot that task's
+//	number of voluntary context switches, and add that task to the
+//	holdout list.
+// rcu_tasks_postscan():
+//	Invoke synchronize_srcu() to ensure that all tasks that were
+//	in the process of exiting (and which thus might not know to
+//	synchronize with this RCU Tasks grace period) have completed
+//	exiting.
+// check_all_holdout_tasks(), repeatedly until holdout list is empty:
+//	Scans the holdout list, attempting to identify a quiescent state
+//	for each task on the list.  If there is a quiescent state, the
+//	corresponding task is removed from the holdout list.
+// rcu_tasks_postgp():
+//	Invokes synchronize_rcu() in order to ensure that all prior
+//	t->on_rq and t->nvcsw transitions are seen by all CPUs and tasks
+//	to have happened before the end of this RCU Tasks grace period.
+//	Again, this works because all such transitions are carried out
+//	with interrupts disabled.
+//
+// For each exiting task, the exit_tasks_rcu_start() and
+// exit_tasks_rcu_finish() functions begin and end, respectively, the SRCU
+// read-side critical sections waited for by rcu_tasks_postscan().
+//
+// Pre-grace-period update-side code is ordered before the grace
+// via the raw_spin_lock.*rcu_node().  Pre-grace-period read-side code
+// is ordered before the grace period via synchronize_rcu() call in
+// rcu_tasks_pregp_step() and by the scheduler's locks and interrupt
+// disabling.
+
+/* Pre-grace-period preparation. */
+static void rcu_tasks_pregp_step(struct list_head *hop)
+{
+	/*
+	 * Wait for all pre-existing t->on_rq and t->nvcsw transitions
+	 * to complete.  Invoking synchronize_rcu() suffices because all
+	 * these transitions occur with interrupts disabled.  Without this
+	 * synchronize_rcu(), a read-side critical section that started
+	 * before the grace period might be incorrectly seen as having
+	 * started after the grace period.
+	 *
+	 * This synchronize_rcu() also dispenses with the need for a
+	 * memory barrier on the first store to t->rcu_tasks_holdout,
+	 * as it forces the store to happen after the beginning of the
+	 * grace period.
+	 */
+	synchronize_rcu();
+}
+
+/* Per-task initial processing. */
+static void rcu_tasks_pertask(struct task_struct *t, struct list_head *hop)
+{
+	if (t != current && READ_ONCE(t->on_rq) && !is_idle_task(t)) {
+		get_task_struct(t);
+		t->rcu_tasks_nvcsw = READ_ONCE(t->nvcsw);
+		WRITE_ONCE(t->rcu_tasks_holdout, true);
+		list_add(&t->rcu_tasks_holdout_list, hop);
+	}
+}
+
+/* Processing between scanning taskslist and draining the holdout list. */
+static void rcu_tasks_postscan(struct list_head *hop)
+{
+	/*
+	 * Exiting tasks may escape the tasklist scan. Those are vulnerable
+	 * until their final schedule() with TASK_DEAD state. To cope with
+	 * this, divide the fragile exit path part in two intersecting
+	 * read side critical sections:
+	 *
+	 * 1) An _SRCU_ read side starting before calling exit_notify(),
+	 *    which may remove the task from the tasklist, and ending after
+	 *    the final preempt_disable() call in do_exit().
+	 *
+	 * 2) An _RCU_ read side starting with the final preempt_disable()
+	 *    call in do_exit() and ending with the final call to schedule()
+	 *    with TASK_DEAD state.
+	 *
+	 * This handles the part 1). And postgp will handle part 2) with a
+	 * call to synchronize_rcu().
+	 */
+	synchronize_srcu(&tasks_rcu_exit_srcu);
+}
+
+/* See if tasks are still holding out, complain if so. */
+static void check_holdout_task(struct task_struct *t,
+			       bool needreport, bool *firstreport)
+{
+	int cpu;
+
+	if (!READ_ONCE(t->rcu_tasks_holdout) ||
+	    t->rcu_tasks_nvcsw != READ_ONCE(t->nvcsw) ||
+	    !READ_ONCE(t->on_rq) ||
+	    (IS_ENABLED(CONFIG_NO_HZ_FULL) &&
+	     !is_idle_task(t) && t->rcu_tasks_idle_cpu >= 0)) {
+		WRITE_ONCE(t->rcu_tasks_holdout, false);
+		list_del_init(&t->rcu_tasks_holdout_list);
+		put_task_struct(t);
+		return;
+	}
+	rcu_request_urgent_qs_task(t);
+	if (!needreport)
+		return;
+	if (*firstreport) {
+		pr_err("INFO: rcu_tasks detected stalls on tasks:\n");
+		*firstreport = false;
+	}
+	cpu = task_cpu(t);
+	pr_alert("%p: %c%c nvcsw: %lu/%lu holdout: %d idle_cpu: %d/%d\n",
+		 t, ".I"[is_idle_task(t)],
+		 "N."[cpu < 0 || !tick_nohz_full_cpu(cpu)],
+		 t->rcu_tasks_nvcsw, t->nvcsw, t->rcu_tasks_holdout,
+		 t->rcu_tasks_idle_cpu, cpu);
+	sched_show_task(t);
+}
+
+/* Scan the holdout lists for tasks no longer holding out. */
+static void check_all_holdout_tasks(struct list_head *hop,
+				    bool needreport, bool *firstreport)
+{
+	struct task_struct *t, *t1;
+
+	list_for_each_entry_safe(t, t1, hop, rcu_tasks_holdout_list) {
+		check_holdout_task(t, needreport, firstreport);
+		cond_resched();
+	}
+}
+
+/* Finish off the Tasks-RCU grace period. */
+static void rcu_tasks_postgp(struct rcu_tasks *rtp)
+{
+	/*
+	 * Because ->on_rq and ->nvcsw are not guaranteed to have a full
+	 * memory barriers prior to them in the schedule() path, memory
+	 * reordering on other CPUs could cause their RCU-tasks read-side
+	 * critical sections to extend past the end of the grace period.
+	 * However, because these ->nvcsw updates are carried out with
+	 * interrupts disabled, we can use synchronize_rcu() to force the
+	 * needed ordering on all such CPUs.
+	 *
+	 * This synchronize_rcu() also confines all ->rcu_tasks_holdout
+	 * accesses to be within the grace period, avoiding the need for
+	 * memory barriers for ->rcu_tasks_holdout accesses.
+	 *
+	 * In addition, this synchronize_rcu() waits for exiting tasks
+	 * to complete their final preempt_disable() region of execution,
+	 * cleaning up after synchronize_srcu(&tasks_rcu_exit_srcu),
+	 * enforcing the whole region before tasklist removal until
+	 * the final schedule() with TASK_DEAD state to be an RCU TASKS
+	 * read side critical section.
+	 */
+	synchronize_rcu();
+}
+
+void call_rcu_tasks(struct rcu_head *rhp, rcu_callback_t func);
+DEFINE_RCU_TASKS(rcu_tasks, rcu_tasks_wait_gp, call_rcu_tasks, "RCU Tasks");
+
+/**
+ * call_rcu_tasks() - Queue an RCU for invocation task-based grace period
+ * @rhp: structure to be used for queueing the RCU updates.
+ * @func: actual callback function to be invoked after the grace period
+ *
+ * The callback function will be invoked some time after a full grace
+ * period elapses, in other words after all currently executing RCU
+ * read-side critical sections have completed. call_rcu_tasks() assumes
+ * that the read-side critical sections end at a voluntary context
+ * switch (not a preemption!), cond_resched_tasks_rcu_qs(), entry into idle,
+ * or transition to usermode execution.  As such, there are no read-side
+ * primitives analogous to rcu_read_lock() and rcu_read_unlock() because
+ * this primitive is intended to determine that all tasks have passed
+ * through a safe state, not so much for data-structure synchronization.
+ *
+ * See the description of call_rcu() for more detailed information on
+ * memory ordering guarantees.
+ */
+void call_rcu_tasks(struct rcu_head *rhp, rcu_callback_t func)
+{
+	call_rcu_tasks_generic(rhp, func, &rcu_tasks);
+}
+EXPORT_SYMBOL_GPL(call_rcu_tasks);
+
+/**
+ * synchronize_rcu_tasks - wait until an rcu-tasks grace period has elapsed.
+ *
+ * Control will return to the caller some time after a full rcu-tasks
+ * grace period has elapsed, in other words after all currently
+ * executing rcu-tasks read-side critical sections have elapsed.  These
+ * read-side critical sections are delimited by calls to schedule(),
+ * cond_resched_tasks_rcu_qs(), idle execution, userspace execution, calls
+ * to synchronize_rcu_tasks(), and (in theory, anyway) cond_resched().
+ *
+ * This is a very specialized primitive, intended only for a few uses in
+ * tracing and other situations requiring manipulation of function
+ * preambles and profiling hooks.  The synchronize_rcu_tasks() function
+ * is not (yet) intended for heavy use from multiple CPUs.
+ *
+ * See the description of synchronize_rcu() for more detailed information
+ * on memory ordering guarantees.
+ */
+void synchronize_rcu_tasks(void)
+{
+	synchronize_rcu_tasks_generic(&rcu_tasks);
+}
+EXPORT_SYMBOL_GPL(synchronize_rcu_tasks);
+
+/**
+ * rcu_barrier_tasks - Wait for in-flight call_rcu_tasks() callbacks.
+ *
+ * Although the current implementation is guaranteed to wait, it is not
+ * obligated to, for example, if there are no pending callbacks.
+ */
+void rcu_barrier_tasks(void)
+{
+	rcu_barrier_tasks_generic(&rcu_tasks);
+}
+EXPORT_SYMBOL_GPL(rcu_barrier_tasks);
+
+static int __init rcu_spawn_tasks_kthread(void)
+{
+	cblist_init_generic(&rcu_tasks);
+	rcu_tasks.gp_sleep = HZ / 10;
+	rcu_tasks.init_fract = HZ / 10;
+	rcu_tasks.pregp_func = rcu_tasks_pregp_step;
+	rcu_tasks.pertask_func = rcu_tasks_pertask;
+	rcu_tasks.postscan_func = rcu_tasks_postscan;
+	rcu_tasks.holdouts_func = check_all_holdout_tasks;
+	rcu_tasks.postgp_func = rcu_tasks_postgp;
+	rcu_spawn_tasks_kthread_generic(&rcu_tasks);
+	return 0;
+}
+
+#if !defined(CONFIG_TINY_RCU)
+void show_rcu_tasks_classic_gp_kthread(void)
+{
+	show_rcu_tasks_generic_gp_kthread(&rcu_tasks, "");
+}
+EXPORT_SYMBOL_GPL(show_rcu_tasks_classic_gp_kthread);
+#endif // !defined(CONFIG_TINY_RCU)
+
+/*
+ * Contribute to protect against tasklist scan blind spot while the
+ * task is exiting and may be removed from the tasklist. See
+ * corresponding synchronize_srcu() for further details.
+ */
+void exit_tasks_rcu_start(void) __acquires(&tasks_rcu_exit_srcu)
+{
+	current->rcu_tasks_idx = __srcu_read_lock(&tasks_rcu_exit_srcu);
+}
+
+/*
+ * Contribute to protect against tasklist scan blind spot while the
+ * task is exiting and may be removed from the tasklist. See
+ * corresponding synchronize_srcu() for further details.
+ */
+void exit_tasks_rcu_stop(void) __releases(&tasks_rcu_exit_srcu)
+{
+	struct task_struct *t = current;
+
+	__srcu_read_unlock(&tasks_rcu_exit_srcu, t->rcu_tasks_idx);
+}
+
+/*
+ * Contribute to protect against tasklist scan blind spot while the
+ * task is exiting and may be removed from the tasklist. See
+ * corresponding synchronize_srcu() for further details.
+ */
+void exit_tasks_rcu_finish(void)
+{
+	exit_tasks_rcu_stop();
+	exit_tasks_rcu_finish_trace(current);
+}
+
+#else /* #ifdef CONFIG_TASKS_RCU */
+void exit_tasks_rcu_start(void) { }
+void exit_tasks_rcu_stop(void) { }
+void exit_tasks_rcu_finish(void) { exit_tasks_rcu_finish_trace(current); }
+#endif /* #else #ifdef CONFIG_TASKS_RCU */
+
+#ifdef CONFIG_TASKS_RUDE_RCU
+
+////////////////////////////////////////////////////////////////////////
+//
+// "Rude" variant of Tasks RCU, inspired by Steve Rostedt's trick of
+// passing an empty function to schedule_on_each_cpu().  This approach
+// provides an asynchronous call_rcu_tasks_rude() API and batching of
+// concurrent calls to the synchronous synchronize_rcu_tasks_rude() API.
+// This invokes schedule_on_each_cpu() in order to send IPIs far and wide
+// and induces otherwise unnecessary context switches on all online CPUs,
+// whether idle or not.
+//
+// Callback handling is provided by the rcu_tasks_kthread() function.
+//
+// Ordering is provided by the scheduler's context-switch code.
+
+// Empty function to allow workqueues to force a context switch.
+static void rcu_tasks_be_rude(struct work_struct *work)
+{
+}
+
+// Wait for one rude RCU-tasks grace period.
+static void rcu_tasks_rude_wait_gp(struct rcu_tasks *rtp)
+{
+	rtp->n_ipis += cpumask_weight(cpu_online_mask);
+	schedule_on_each_cpu(rcu_tasks_be_rude);
+}
+
+void call_rcu_tasks_rude(struct rcu_head *rhp, rcu_callback_t func);
+DEFINE_RCU_TASKS(rcu_tasks_rude, rcu_tasks_rude_wait_gp, call_rcu_tasks_rude,
+		 "RCU Tasks Rude");
+
+/**
+ * call_rcu_tasks_rude() - Queue a callback rude task-based grace period
+ * @rhp: structure to be used for queueing the RCU updates.
+ * @func: actual callback function to be invoked after the grace period
+ *
+ * The callback function will be invoked some time after a full grace
+ * period elapses, in other words after all currently executing RCU
+ * read-side critical sections have completed. call_rcu_tasks_rude()
+ * assumes that the read-side critical sections end at context switch,
+ * cond_resched_tasks_rcu_qs(), or transition to usermode execution (as
+ * usermode execution is schedulable). As such, there are no read-side
+ * primitives analogous to rcu_read_lock() and rcu_read_unlock() because
+ * this primitive is intended to determine that all tasks have passed
+ * through a safe state, not so much for data-structure synchronization.
+ *
+ * See the description of call_rcu() for more detailed information on
+ * memory ordering guarantees.
+ */
+void call_rcu_tasks_rude(struct rcu_head *rhp, rcu_callback_t func)
+{
+	call_rcu_tasks_generic(rhp, func, &rcu_tasks_rude);
+}
+EXPORT_SYMBOL_GPL(call_rcu_tasks_rude);
+
+/**
+ * synchronize_rcu_tasks_rude - wait for a rude rcu-tasks grace period
+ *
+ * Control will return to the caller some time after a rude rcu-tasks
+ * grace period has elapsed, in other words after all currently
+ * executing rcu-tasks read-side critical sections have elapsed.  These
+ * read-side critical sections are delimited by calls to schedule(),
+ * cond_resched_tasks_rcu_qs(), userspace execution (which is a schedulable
+ * context), and (in theory, anyway) cond_resched().
+ *
+ * This is a very specialized primitive, intended only for a few uses in
+ * tracing and other situations requiring manipulation of function preambles
+ * and profiling hooks.  The synchronize_rcu_tasks_rude() function is not
+ * (yet) intended for heavy use from multiple CPUs.
+ *
+ * See the description of synchronize_rcu() for more detailed information
+ * on memory ordering guarantees.
+ */
+void synchronize_rcu_tasks_rude(void)
+{
+	synchronize_rcu_tasks_generic(&rcu_tasks_rude);
+}
+EXPORT_SYMBOL_GPL(synchronize_rcu_tasks_rude);
+
+/**
+ * rcu_barrier_tasks_rude - Wait for in-flight call_rcu_tasks_rude() callbacks.
+ *
+ * Although the current implementation is guaranteed to wait, it is not
+ * obligated to, for example, if there are no pending callbacks.
+ */
+void rcu_barrier_tasks_rude(void)
+{
+	rcu_barrier_tasks_generic(&rcu_tasks_rude);
+}
+EXPORT_SYMBOL_GPL(rcu_barrier_tasks_rude);
+
+static int __init rcu_spawn_tasks_rude_kthread(void)
+{
+	cblist_init_generic(&rcu_tasks_rude);
+	rcu_tasks_rude.gp_sleep = HZ / 10;
+	rcu_spawn_tasks_kthread_generic(&rcu_tasks_rude);
+	return 0;
+}
+
+#if !defined(CONFIG_TINY_RCU)
+void show_rcu_tasks_rude_gp_kthread(void)
+{
+	show_rcu_tasks_generic_gp_kthread(&rcu_tasks_rude, "");
+}
+EXPORT_SYMBOL_GPL(show_rcu_tasks_rude_gp_kthread);
+#endif // !defined(CONFIG_TINY_RCU)
+#endif /* #ifdef CONFIG_TASKS_RUDE_RCU */
+
+////////////////////////////////////////////////////////////////////////
+//
+// Tracing variant of Tasks RCU.  This variant is designed to be used
+// to protect tracing hooks, including those of BPF.  This variant
+// therefore:
+//
+// 1.	Has explicit read-side markers to allow finite grace periods
+//	in the face of in-kernel loops for PREEMPT=n builds.
+//
+// 2.	Protects code in the idle loop, exception entry/exit, and
+//	CPU-hotplug code paths, similar to the capabilities of SRCU.
+//
+// 3.	Avoids expensive read-side instructions, having overhead similar
+//	to that of Preemptible RCU.
+//
+// There are of course downsides.  For example, the grace-period code
+// can send IPIs to CPUs, even when those CPUs are in the idle loop or
+// in nohz_full userspace.  If needed, these downsides can be at least
+// partially remedied.
+//
+// Perhaps most important, this variant of RCU does not affect the vanilla
+// flavors, rcu_preempt and rcu_sched.  The fact that RCU Tasks Trace
+// readers can operate from idle, offline, and exception entry/exit in no
+// way allows rcu_preempt and rcu_sched readers to also do so.
+//
+// The implementation uses rcu_tasks_wait_gp(), which relies on function
+// pointers in the rcu_tasks structure.  The rcu_spawn_tasks_trace_kthread()
+// function sets these function pointers up so that rcu_tasks_wait_gp()
+// invokes these functions in this order:
+//
+// rcu_tasks_trace_pregp_step():
+//	Disables CPU hotplug, adds all currently executing tasks to the
+//	holdout list, then checks the state of all tasks that blocked
+//	or were preempted within their current RCU Tasks Trace read-side
+//	critical section, adding them to the holdout list if appropriate.
+//	Finally, this function re-enables CPU hotplug.
+// The ->pertask_func() pointer is NULL, so there is no per-task processing.
+// rcu_tasks_trace_postscan():
+//	Invokes synchronize_rcu() to wait for late-stage exiting tasks
+//	to finish exiting.
+// check_all_holdout_tasks_trace(), repeatedly until holdout list is empty:
+//	Scans the holdout list, attempting to identify a quiescent state
+//	for each task on the list.  If there is a quiescent state, the
+//	corresponding task is removed from the holdout list.  Once this
+//	list is empty, the grace period has completed.
+// rcu_tasks_trace_postgp():
+//	Provides the needed full memory barrier and does debug checks.
+//
+// The exit_tasks_rcu_finish_trace() synchronizes with exiting tasks.
+//
+// Pre-grace-period update-side code is ordered before the grace period
+// via the ->cbs_lock and barriers in rcu_tasks_kthread().  Pre-grace-period
+// read-side code is ordered before the grace period by atomic operations
+// on .b.need_qs flag of each task involved in this process, or by scheduler
+// context-switch ordering (for locked-down non-running readers).
+
+// The lockdep state must be outside of #ifdef to be useful.
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+static struct lock_class_key rcu_lock_trace_key;
+struct lockdep_map rcu_trace_lock_map =
+	STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_trace", &rcu_lock_trace_key);
+EXPORT_SYMBOL_GPL(rcu_trace_lock_map);
+#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
+#ifdef CONFIG_TASKS_TRACE_RCU
+
+// Record outstanding IPIs to each CPU.  No point in sending two...
+static DEFINE_PER_CPU(bool, trc_ipi_to_cpu);
+
+// The number of detections of task quiescent state relying on
+// heavyweight readers executing explicit memory barriers.
+static unsigned long n_heavy_reader_attempts;
+static unsigned long n_heavy_reader_updates;
+static unsigned long n_heavy_reader_ofl_updates;
+static unsigned long n_trc_holdouts;
+
+void call_rcu_tasks_trace(struct rcu_head *rhp, rcu_callback_t func);
+DEFINE_RCU_TASKS(rcu_tasks_trace, rcu_tasks_wait_gp, call_rcu_tasks_trace,
+		 "RCU Tasks Trace");
+
+/* Load from ->trc_reader_special.b.need_qs with proper ordering. */
+static u8 rcu_ld_need_qs(struct task_struct *t)
+{
+	smp_mb(); // Enforce full grace-period ordering.
+	return smp_load_acquire(&t->trc_reader_special.b.need_qs);
+}
+
+/* Store to ->trc_reader_special.b.need_qs with proper ordering. */
+static void rcu_st_need_qs(struct task_struct *t, u8 v)
+{
+	smp_store_release(&t->trc_reader_special.b.need_qs, v);
+	smp_mb(); // Enforce full grace-period ordering.
+}
+
+/*
+ * Do a cmpxchg() on ->trc_reader_special.b.need_qs, allowing for
+ * the four-byte operand-size restriction of some platforms.
+ * Returns the old value, which is often ignored.
+ */
+u8 rcu_trc_cmpxchg_need_qs(struct task_struct *t, u8 old, u8 new)
+{
+	union rcu_special ret;
+	union rcu_special trs_old = READ_ONCE(t->trc_reader_special);
+	union rcu_special trs_new = trs_old;
+
+	if (trs_old.b.need_qs != old)
+		return trs_old.b.need_qs;
+	trs_new.b.need_qs = new;
+	ret.s = cmpxchg(&t->trc_reader_special.s, trs_old.s, trs_new.s);
+	return ret.b.need_qs;
+}
+EXPORT_SYMBOL_GPL(rcu_trc_cmpxchg_need_qs);
+
+/*
+ * If we are the last reader, signal the grace-period kthread.
+ * Also remove from the per-CPU list of blocked tasks.
+ */
+void rcu_read_unlock_trace_special(struct task_struct *t)
+{
+	unsigned long flags;
+	struct rcu_tasks_percpu *rtpcp;
+	union rcu_special trs;
+
+	// Open-coded full-word version of rcu_ld_need_qs().
+	smp_mb(); // Enforce full grace-period ordering.
+	trs = smp_load_acquire(&t->trc_reader_special);
+
+	if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB) && t->trc_reader_special.b.need_mb)
+		smp_mb(); // Pairs with update-side barriers.
+	// Update .need_qs before ->trc_reader_nesting for irq/NMI handlers.
+	if (trs.b.need_qs == (TRC_NEED_QS_CHECKED | TRC_NEED_QS)) {
+		u8 result = rcu_trc_cmpxchg_need_qs(t, TRC_NEED_QS_CHECKED | TRC_NEED_QS,
+						       TRC_NEED_QS_CHECKED);
+
+		WARN_ONCE(result != trs.b.need_qs, "%s: result = %d", __func__, result);
+	}
+	if (trs.b.blocked) {
+		rtpcp = per_cpu_ptr(rcu_tasks_trace.rtpcpu, t->trc_blkd_cpu);
+		raw_spin_lock_irqsave_rcu_node(rtpcp, flags);
+		list_del_init(&t->trc_blkd_node);
+		WRITE_ONCE(t->trc_reader_special.b.blocked, false);
+		raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags);
+	}
+	WRITE_ONCE(t->trc_reader_nesting, 0);
+}
+EXPORT_SYMBOL_GPL(rcu_read_unlock_trace_special);
+
+/* Add a newly blocked reader task to its CPU's list. */
+void rcu_tasks_trace_qs_blkd(struct task_struct *t)
+{
+	unsigned long flags;
+	struct rcu_tasks_percpu *rtpcp;
+
+	local_irq_save(flags);
+	rtpcp = this_cpu_ptr(rcu_tasks_trace.rtpcpu);
+	raw_spin_lock_rcu_node(rtpcp); // irqs already disabled
+	t->trc_blkd_cpu = smp_processor_id();
+	if (!rtpcp->rtp_blkd_tasks.next)
+		INIT_LIST_HEAD(&rtpcp->rtp_blkd_tasks);
+	list_add(&t->trc_blkd_node, &rtpcp->rtp_blkd_tasks);
+	WRITE_ONCE(t->trc_reader_special.b.blocked, true);
+	raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags);
+}
+EXPORT_SYMBOL_GPL(rcu_tasks_trace_qs_blkd);
+
+/* Add a task to the holdout list, if it is not already on the list. */
+static void trc_add_holdout(struct task_struct *t, struct list_head *bhp)
+{
+	if (list_empty(&t->trc_holdout_list)) {
+		get_task_struct(t);
+		list_add(&t->trc_holdout_list, bhp);
+		n_trc_holdouts++;
+	}
+}
+
+/* Remove a task from the holdout list, if it is in fact present. */
+static void trc_del_holdout(struct task_struct *t)
+{
+	if (!list_empty(&t->trc_holdout_list)) {
+		list_del_init(&t->trc_holdout_list);
+		put_task_struct(t);
+		n_trc_holdouts--;
+	}
+}
+
+/* IPI handler to check task state. */
+static void trc_read_check_handler(void *t_in)
+{
+	int nesting;
+	struct task_struct *t = current;
+	struct task_struct *texp = t_in;
+
+	// If the task is no longer running on this CPU, leave.
+	if (unlikely(texp != t))
+		goto reset_ipi; // Already on holdout list, so will check later.
+
+	// If the task is not in a read-side critical section, and
+	// if this is the last reader, awaken the grace-period kthread.
+	nesting = READ_ONCE(t->trc_reader_nesting);
+	if (likely(!nesting)) {
+		rcu_trc_cmpxchg_need_qs(t, 0, TRC_NEED_QS_CHECKED);
+		goto reset_ipi;
+	}
+	// If we are racing with an rcu_read_unlock_trace(), try again later.
+	if (unlikely(nesting < 0))
+		goto reset_ipi;
+
+	// Get here if the task is in a read-side critical section.
+	// Set its state so that it will update state for the grace-period
+	// kthread upon exit from that critical section.
+	rcu_trc_cmpxchg_need_qs(t, 0, TRC_NEED_QS | TRC_NEED_QS_CHECKED);
+
+reset_ipi:
+	// Allow future IPIs to be sent on CPU and for task.
+	// Also order this IPI handler against any later manipulations of
+	// the intended task.
+	smp_store_release(per_cpu_ptr(&trc_ipi_to_cpu, smp_processor_id()), false); // ^^^
+	smp_store_release(&texp->trc_ipi_to_cpu, -1); // ^^^
+}
+
+/* Callback function for scheduler to check locked-down task.  */
+static int trc_inspect_reader(struct task_struct *t, void *bhp_in)
+{
+	struct list_head *bhp = bhp_in;
+	int cpu = task_cpu(t);
+	int nesting;
+	bool ofl = cpu_is_offline(cpu);
+
+	if (task_curr(t) && !ofl) {
+		// If no chance of heavyweight readers, do it the hard way.
+		if (!IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB))
+			return -EINVAL;
+
+		// If heavyweight readers are enabled on the remote task,
+		// we can inspect its state despite its currently running.
+		// However, we cannot safely change its state.
+		n_heavy_reader_attempts++;
+		// Check for "running" idle tasks on offline CPUs.
+		if (!rcu_dynticks_zero_in_eqs(cpu, &t->trc_reader_nesting))
+			return -EINVAL; // No quiescent state, do it the hard way.
+		n_heavy_reader_updates++;
+		nesting = 0;
+	} else {
+		// The task is not running, so C-language access is safe.
+		nesting = t->trc_reader_nesting;
+		WARN_ON_ONCE(ofl && task_curr(t) && !is_idle_task(t));
+		if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB) && ofl)
+			n_heavy_reader_ofl_updates++;
+	}
+
+	// If not exiting a read-side critical section, mark as checked
+	// so that the grace-period kthread will remove it from the
+	// holdout list.
+	if (!nesting) {
+		rcu_trc_cmpxchg_need_qs(t, 0, TRC_NEED_QS_CHECKED);
+		return 0;  // In QS, so done.
+	}
+	if (nesting < 0)
+		return -EINVAL; // Reader transitioning, try again later.
+
+	// The task is in a read-side critical section, so set up its
+	// state so that it will update state upon exit from that critical
+	// section.
+	if (!rcu_trc_cmpxchg_need_qs(t, 0, TRC_NEED_QS | TRC_NEED_QS_CHECKED))
+		trc_add_holdout(t, bhp);
+	return 0;
+}
+
+/* Attempt to extract the state for the specified task. */
+static void trc_wait_for_one_reader(struct task_struct *t,
+				    struct list_head *bhp)
+{
+	int cpu;
+
+	// If a previous IPI is still in flight, let it complete.
+	if (smp_load_acquire(&t->trc_ipi_to_cpu) != -1) // Order IPI
+		return;
+
+	// The current task had better be in a quiescent state.
+	if (t == current) {
+		rcu_trc_cmpxchg_need_qs(t, 0, TRC_NEED_QS_CHECKED);
+		WARN_ON_ONCE(READ_ONCE(t->trc_reader_nesting));
+		return;
+	}
+
+	// Attempt to nail down the task for inspection.
+	get_task_struct(t);
+	if (!task_call_func(t, trc_inspect_reader, bhp)) {
+		put_task_struct(t);
+		return;
+	}
+	put_task_struct(t);
+
+	// If this task is not yet on the holdout list, then we are in
+	// an RCU read-side critical section.  Otherwise, the invocation of
+	// trc_add_holdout() that added it to the list did the necessary
+	// get_task_struct().  Either way, the task cannot be freed out
+	// from under this code.
+
+	// If currently running, send an IPI, either way, add to list.
+	trc_add_holdout(t, bhp);
+	if (task_curr(t) &&
+	    time_after(jiffies + 1, rcu_tasks_trace.gp_start + rcu_task_ipi_delay)) {
+		// The task is currently running, so try IPIing it.
+		cpu = task_cpu(t);
+
+		// If there is already an IPI outstanding, let it happen.
+		if (per_cpu(trc_ipi_to_cpu, cpu) || t->trc_ipi_to_cpu >= 0)
+			return;
+
+		per_cpu(trc_ipi_to_cpu, cpu) = true;
+		t->trc_ipi_to_cpu = cpu;
+		rcu_tasks_trace.n_ipis++;
+		if (smp_call_function_single(cpu, trc_read_check_handler, t, 0)) {
+			// Just in case there is some other reason for
+			// failure than the target CPU being offline.
+			WARN_ONCE(1, "%s():  smp_call_function_single() failed for CPU: %d\n",
+				  __func__, cpu);
+			rcu_tasks_trace.n_ipis_fails++;
+			per_cpu(trc_ipi_to_cpu, cpu) = false;
+			t->trc_ipi_to_cpu = -1;
+		}
+	}
+}
+
+/*
+ * Initialize for first-round processing for the specified task.
+ * Return false if task is NULL or already taken care of, true otherwise.
+ */
+static bool rcu_tasks_trace_pertask_prep(struct task_struct *t, bool notself)
+{
+	// During early boot when there is only the one boot CPU, there
+	// is no idle task for the other CPUs.	Also, the grace-period
+	// kthread is always in a quiescent state.  In addition, just return
+	// if this task is already on the list.
+	if (unlikely(t == NULL) || (t == current && notself) || !list_empty(&t->trc_holdout_list))
+		return false;
+
+	rcu_st_need_qs(t, 0);
+	t->trc_ipi_to_cpu = -1;
+	return true;
+}
+
+/* Do first-round processing for the specified task. */
+static void rcu_tasks_trace_pertask(struct task_struct *t, struct list_head *hop)
+{
+	if (rcu_tasks_trace_pertask_prep(t, true))
+		trc_wait_for_one_reader(t, hop);
+}
+
+/* Initialize for a new RCU-tasks-trace grace period. */
+static void rcu_tasks_trace_pregp_step(struct list_head *hop)
+{
+	LIST_HEAD(blkd_tasks);
+	int cpu;
+	unsigned long flags;
+	struct rcu_tasks_percpu *rtpcp;
+	struct task_struct *t;
+
+	// There shouldn't be any old IPIs, but...
+	for_each_possible_cpu(cpu)
+		WARN_ON_ONCE(per_cpu(trc_ipi_to_cpu, cpu));
+
+	// Disable CPU hotplug across the CPU scan for the benefit of
+	// any IPIs that might be needed.  This also waits for all readers
+	// in CPU-hotplug code paths.
+	cpus_read_lock();
+
+	// These rcu_tasks_trace_pertask_prep() calls are serialized to
+	// allow safe access to the hop list.
+	for_each_online_cpu(cpu) {
+		rcu_read_lock();
+		t = cpu_curr_snapshot(cpu);
+		if (rcu_tasks_trace_pertask_prep(t, true))
+			trc_add_holdout(t, hop);
+		rcu_read_unlock();
+		cond_resched_tasks_rcu_qs();
+	}
+
+	// Only after all running tasks have been accounted for is it
+	// safe to take care of the tasks that have blocked within their
+	// current RCU tasks trace read-side critical section.
+	for_each_possible_cpu(cpu) {
+		rtpcp = per_cpu_ptr(rcu_tasks_trace.rtpcpu, cpu);
+		raw_spin_lock_irqsave_rcu_node(rtpcp, flags);
+		list_splice_init(&rtpcp->rtp_blkd_tasks, &blkd_tasks);
+		while (!list_empty(&blkd_tasks)) {
+			rcu_read_lock();
+			t = list_first_entry(&blkd_tasks, struct task_struct, trc_blkd_node);
+			list_del_init(&t->trc_blkd_node);
+			list_add(&t->trc_blkd_node, &rtpcp->rtp_blkd_tasks);
+			raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags);
+			rcu_tasks_trace_pertask(t, hop);
+			rcu_read_unlock();
+			raw_spin_lock_irqsave_rcu_node(rtpcp, flags);
+		}
+		raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags);
+		cond_resched_tasks_rcu_qs();
+	}
+
+	// Re-enable CPU hotplug now that the holdout list is populated.
+	cpus_read_unlock();
+}
+
+/*
+ * Do intermediate processing between task and holdout scans.
+ */
+static void rcu_tasks_trace_postscan(struct list_head *hop)
+{
+	// Wait for late-stage exiting tasks to finish exiting.
+	// These might have passed the call to exit_tasks_rcu_finish().
+
+	// If you remove the following line, update rcu_trace_implies_rcu_gp()!!!
+	synchronize_rcu();
+	// Any tasks that exit after this point will set
+	// TRC_NEED_QS_CHECKED in ->trc_reader_special.b.need_qs.
+}
+
+/* Communicate task state back to the RCU tasks trace stall warning request. */
+struct trc_stall_chk_rdr {
+	int nesting;
+	int ipi_to_cpu;
+	u8 needqs;
+};
+
+static int trc_check_slow_task(struct task_struct *t, void *arg)
+{
+	struct trc_stall_chk_rdr *trc_rdrp = arg;
+
+	if (task_curr(t) && cpu_online(task_cpu(t)))
+		return false; // It is running, so decline to inspect it.
+	trc_rdrp->nesting = READ_ONCE(t->trc_reader_nesting);
+	trc_rdrp->ipi_to_cpu = READ_ONCE(t->trc_ipi_to_cpu);
+	trc_rdrp->needqs = rcu_ld_need_qs(t);
+	return true;
+}
+
+/* Show the state of a task stalling the current RCU tasks trace GP. */
+static void show_stalled_task_trace(struct task_struct *t, bool *firstreport)
+{
+	int cpu;
+	struct trc_stall_chk_rdr trc_rdr;
+	bool is_idle_tsk = is_idle_task(t);
+
+	if (*firstreport) {
+		pr_err("INFO: rcu_tasks_trace detected stalls on tasks:\n");
+		*firstreport = false;
+	}
+	cpu = task_cpu(t);
+	if (!task_call_func(t, trc_check_slow_task, &trc_rdr))
+		pr_alert("P%d: %c%c\n",
+			 t->pid,
+			 ".I"[t->trc_ipi_to_cpu >= 0],
+			 ".i"[is_idle_tsk]);
+	else
+		pr_alert("P%d: %c%c%c%c nesting: %d%c%c cpu: %d%s\n",
+			 t->pid,
+			 ".I"[trc_rdr.ipi_to_cpu >= 0],
+			 ".i"[is_idle_tsk],
+			 ".N"[cpu >= 0 && tick_nohz_full_cpu(cpu)],
+			 ".B"[!!data_race(t->trc_reader_special.b.blocked)],
+			 trc_rdr.nesting,
+			 " !CN"[trc_rdr.needqs & 0x3],
+			 " ?"[trc_rdr.needqs > 0x3],
+			 cpu, cpu_online(cpu) ? "" : "(offline)");
+	sched_show_task(t);
+}
+
+/* List stalled IPIs for RCU tasks trace. */
+static void show_stalled_ipi_trace(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		if (per_cpu(trc_ipi_to_cpu, cpu))
+			pr_alert("\tIPI outstanding to CPU %d\n", cpu);
+}
+
+/* Do one scan of the holdout list. */
+static void check_all_holdout_tasks_trace(struct list_head *hop,
+					  bool needreport, bool *firstreport)
+{
+	struct task_struct *g, *t;
+
+	// Disable CPU hotplug across the holdout list scan for IPIs.
+	cpus_read_lock();
+
+	list_for_each_entry_safe(t, g, hop, trc_holdout_list) {
+		// If safe and needed, try to check the current task.
+		if (READ_ONCE(t->trc_ipi_to_cpu) == -1 &&
+		    !(rcu_ld_need_qs(t) & TRC_NEED_QS_CHECKED))
+			trc_wait_for_one_reader(t, hop);
+
+		// If check succeeded, remove this task from the list.
+		if (smp_load_acquire(&t->trc_ipi_to_cpu) == -1 &&
+		    rcu_ld_need_qs(t) == TRC_NEED_QS_CHECKED)
+			trc_del_holdout(t);
+		else if (needreport)
+			show_stalled_task_trace(t, firstreport);
+		cond_resched_tasks_rcu_qs();
+	}
+
+	// Re-enable CPU hotplug now that the holdout list scan has completed.
+	cpus_read_unlock();
+
+	if (needreport) {
+		if (*firstreport)
+			pr_err("INFO: rcu_tasks_trace detected stalls? (Late IPI?)\n");
+		show_stalled_ipi_trace();
+	}
+}
+
+static void rcu_tasks_trace_empty_fn(void *unused)
+{
+}
+
+/* Wait for grace period to complete and provide ordering. */
+static void rcu_tasks_trace_postgp(struct rcu_tasks *rtp)
+{
+	int cpu;
+
+	// Wait for any lingering IPI handlers to complete.  Note that
+	// if a CPU has gone offline or transitioned to userspace in the
+	// meantime, all IPI handlers should have been drained beforehand.
+	// Yes, this assumes that CPUs process IPIs in order.  If that ever
+	// changes, there will need to be a recheck and/or timed wait.
+	for_each_online_cpu(cpu)
+		if (WARN_ON_ONCE(smp_load_acquire(per_cpu_ptr(&trc_ipi_to_cpu, cpu))))
+			smp_call_function_single(cpu, rcu_tasks_trace_empty_fn, NULL, 1);
+
+	smp_mb(); // Caller's code must be ordered after wakeup.
+		  // Pairs with pretty much every ordering primitive.
+}
+
+/* Report any needed quiescent state for this exiting task. */
+static void exit_tasks_rcu_finish_trace(struct task_struct *t)
+{
+	union rcu_special trs = READ_ONCE(t->trc_reader_special);
+
+	rcu_trc_cmpxchg_need_qs(t, 0, TRC_NEED_QS_CHECKED);
+	WARN_ON_ONCE(READ_ONCE(t->trc_reader_nesting));
+	if (WARN_ON_ONCE(rcu_ld_need_qs(t) & TRC_NEED_QS || trs.b.blocked))
+		rcu_read_unlock_trace_special(t);
+	else
+		WRITE_ONCE(t->trc_reader_nesting, 0);
+}
+
+/**
+ * call_rcu_tasks_trace() - Queue a callback trace task-based grace period
+ * @rhp: structure to be used for queueing the RCU updates.
+ * @func: actual callback function to be invoked after the grace period
+ *
+ * The callback function will be invoked some time after a trace rcu-tasks
+ * grace period elapses, in other words after all currently executing
+ * trace rcu-tasks read-side critical sections have completed. These
+ * read-side critical sections are delimited by calls to rcu_read_lock_trace()
+ * and rcu_read_unlock_trace().
+ *
+ * See the description of call_rcu() for more detailed information on
+ * memory ordering guarantees.
+ */
+void call_rcu_tasks_trace(struct rcu_head *rhp, rcu_callback_t func)
+{
+	call_rcu_tasks_generic(rhp, func, &rcu_tasks_trace);
+}
+EXPORT_SYMBOL_GPL(call_rcu_tasks_trace);
+
+/**
+ * synchronize_rcu_tasks_trace - wait for a trace rcu-tasks grace period
+ *
+ * Control will return to the caller some time after a trace rcu-tasks
+ * grace period has elapsed, in other words after all currently executing
+ * trace rcu-tasks read-side critical sections have elapsed. These read-side
+ * critical sections are delimited by calls to rcu_read_lock_trace()
+ * and rcu_read_unlock_trace().
+ *
+ * This is a very specialized primitive, intended only for a few uses in
+ * tracing and other situations requiring manipulation of function preambles
+ * and profiling hooks.  The synchronize_rcu_tasks_trace() function is not
+ * (yet) intended for heavy use from multiple CPUs.
+ *
+ * See the description of synchronize_rcu() for more detailed information
+ * on memory ordering guarantees.
+ */
+void synchronize_rcu_tasks_trace(void)
+{
+	RCU_LOCKDEP_WARN(lock_is_held(&rcu_trace_lock_map), "Illegal synchronize_rcu_tasks_trace() in RCU Tasks Trace read-side critical section");
+	synchronize_rcu_tasks_generic(&rcu_tasks_trace);
+}
+EXPORT_SYMBOL_GPL(synchronize_rcu_tasks_trace);
+
+/**
+ * rcu_barrier_tasks_trace - Wait for in-flight call_rcu_tasks_trace() callbacks.
+ *
+ * Although the current implementation is guaranteed to wait, it is not
+ * obligated to, for example, if there are no pending callbacks.
+ */
+void rcu_barrier_tasks_trace(void)
+{
+	rcu_barrier_tasks_generic(&rcu_tasks_trace);
+}
+EXPORT_SYMBOL_GPL(rcu_barrier_tasks_trace);
+
+static int __init rcu_spawn_tasks_trace_kthread(void)
+{
+	cblist_init_generic(&rcu_tasks_trace);
+	if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB)) {
+		rcu_tasks_trace.gp_sleep = HZ / 10;
+		rcu_tasks_trace.init_fract = HZ / 10;
+	} else {
+		rcu_tasks_trace.gp_sleep = HZ / 200;
+		if (rcu_tasks_trace.gp_sleep <= 0)
+			rcu_tasks_trace.gp_sleep = 1;
+		rcu_tasks_trace.init_fract = HZ / 200;
+		if (rcu_tasks_trace.init_fract <= 0)
+			rcu_tasks_trace.init_fract = 1;
+	}
+	rcu_tasks_trace.pregp_func = rcu_tasks_trace_pregp_step;
+	rcu_tasks_trace.postscan_func = rcu_tasks_trace_postscan;
+	rcu_tasks_trace.holdouts_func = check_all_holdout_tasks_trace;
+	rcu_tasks_trace.postgp_func = rcu_tasks_trace_postgp;
+	rcu_spawn_tasks_kthread_generic(&rcu_tasks_trace);
+	return 0;
+}
+
+#if !defined(CONFIG_TINY_RCU)
+void show_rcu_tasks_trace_gp_kthread(void)
+{
+	char buf[64];
+
+	sprintf(buf, "N%lu h:%lu/%lu/%lu",
+		data_race(n_trc_holdouts),
+		data_race(n_heavy_reader_ofl_updates),
+		data_race(n_heavy_reader_updates),
+		data_race(n_heavy_reader_attempts));
+	show_rcu_tasks_generic_gp_kthread(&rcu_tasks_trace, buf);
+}
+EXPORT_SYMBOL_GPL(show_rcu_tasks_trace_gp_kthread);
+#endif // !defined(CONFIG_TINY_RCU)
+
+#else /* #ifdef CONFIG_TASKS_TRACE_RCU */
+static void exit_tasks_rcu_finish_trace(struct task_struct *t) { }
+#endif /* #else #ifdef CONFIG_TASKS_TRACE_RCU */
+
+#ifndef CONFIG_TINY_RCU
+void show_rcu_tasks_gp_kthreads(void)
+{
+	show_rcu_tasks_classic_gp_kthread();
+	show_rcu_tasks_rude_gp_kthread();
+	show_rcu_tasks_trace_gp_kthread();
+}
+#endif /* #ifndef CONFIG_TINY_RCU */
+
+#ifdef CONFIG_PROVE_RCU
+struct rcu_tasks_test_desc {
+	struct rcu_head rh;
+	const char *name;
+	bool notrun;
+	unsigned long runstart;
+};
+
+static struct rcu_tasks_test_desc tests[] = {
+	{
+		.name = "call_rcu_tasks()",
+		/* If not defined, the test is skipped. */
+		.notrun = IS_ENABLED(CONFIG_TASKS_RCU),
+	},
+	{
+		.name = "call_rcu_tasks_rude()",
+		/* If not defined, the test is skipped. */
+		.notrun = IS_ENABLED(CONFIG_TASKS_RUDE_RCU),
+	},
+	{
+		.name = "call_rcu_tasks_trace()",
+		/* If not defined, the test is skipped. */
+		.notrun = IS_ENABLED(CONFIG_TASKS_TRACE_RCU)
+	}
+};
+
+static void test_rcu_tasks_callback(struct rcu_head *rhp)
+{
+	struct rcu_tasks_test_desc *rttd =
+		container_of(rhp, struct rcu_tasks_test_desc, rh);
+
+	pr_info("Callback from %s invoked.\n", rttd->name);
+
+	rttd->notrun = false;
+}
+
+static void rcu_tasks_initiate_self_tests(void)
+{
+	unsigned long j = jiffies;
+
+	pr_info("Running RCU-tasks wait API self tests\n");
+#ifdef CONFIG_TASKS_RCU
+	tests[0].runstart = j;
+	synchronize_rcu_tasks();
+	call_rcu_tasks(&tests[0].rh, test_rcu_tasks_callback);
+#endif
+
+#ifdef CONFIG_TASKS_RUDE_RCU
+	tests[1].runstart = j;
+	synchronize_rcu_tasks_rude();
+	call_rcu_tasks_rude(&tests[1].rh, test_rcu_tasks_callback);
+#endif
+
+#ifdef CONFIG_TASKS_TRACE_RCU
+	tests[2].runstart = j;
+	synchronize_rcu_tasks_trace();
+	call_rcu_tasks_trace(&tests[2].rh, test_rcu_tasks_callback);
+#endif
+}
+
+/*
+ * Return:  0 - test passed
+ *	    1 - test failed, but have not timed out yet
+ *	   -1 - test failed and timed out
+ */
+static int rcu_tasks_verify_self_tests(void)
+{
+	int ret = 0;
+	int i;
+	unsigned long bst = rcu_task_stall_timeout;
+
+	if (bst <= 0 || bst > RCU_TASK_BOOT_STALL_TIMEOUT)
+		bst = RCU_TASK_BOOT_STALL_TIMEOUT;
+	for (i = 0; i < ARRAY_SIZE(tests); i++) {
+		while (tests[i].notrun) {		// still hanging.
+			if (time_after(jiffies, tests[i].runstart + bst)) {
+				pr_err("%s has failed boot-time tests.\n", tests[i].name);
+				ret = -1;
+				break;
+			}
+			ret = 1;
+			break;
+		}
+	}
+	WARN_ON(ret < 0);
+
+	return ret;
+}
+
+/*
+ * Repeat the rcu_tasks_verify_self_tests() call once every second until the
+ * test passes or has timed out.
+ */
+static struct delayed_work rcu_tasks_verify_work;
+static void rcu_tasks_verify_work_fn(struct work_struct *work __maybe_unused)
+{
+	int ret = rcu_tasks_verify_self_tests();
+
+	if (ret <= 0)
+		return;
+
+	/* Test fails but not timed out yet, reschedule another check */
+	schedule_delayed_work(&rcu_tasks_verify_work, HZ);
+}
+
+static int rcu_tasks_verify_schedule_work(void)
+{
+	INIT_DELAYED_WORK(&rcu_tasks_verify_work, rcu_tasks_verify_work_fn);
+	rcu_tasks_verify_work_fn(NULL);
+	return 0;
+}
+late_initcall(rcu_tasks_verify_schedule_work);
+#else /* #ifdef CONFIG_PROVE_RCU */
+static void rcu_tasks_initiate_self_tests(void) { }
+#endif /* #else #ifdef CONFIG_PROVE_RCU */
+
+void __init rcu_init_tasks_generic(void)
+{
+#ifdef CONFIG_TASKS_RCU
+	rcu_spawn_tasks_kthread();
+#endif
+
+#ifdef CONFIG_TASKS_RUDE_RCU
+	rcu_spawn_tasks_rude_kthread();
+#endif
+
+#ifdef CONFIG_TASKS_TRACE_RCU
+	rcu_spawn_tasks_trace_kthread();
+#endif
+
+	// Run the self-tests.
+	rcu_tasks_initiate_self_tests();
+}
+
+#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
+static inline void rcu_tasks_bootup_oddness(void) {}
+#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
new file mode 100644
index 000000000..a33a8d494
--- /dev/null
+++ b/kernel/rcu/tiny.c
@@ -0,0 +1,266 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
+ *
+ * Copyright IBM Corporation, 2008
+ *
+ * Author: Paul E. McKenney <paulmck@linux.ibm.com>
+ *
+ * For detailed explanation of Read-Copy Update mechanism see -
+ *		Documentation/RCU
+ */
+#include <linux/completion.h>
+#include <linux/interrupt.h>
+#include <linux/notifier.h>
+#include <linux/rcupdate_wait.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/time.h>
+#include <linux/cpu.h>
+#include <linux/prefetch.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+
+#include "rcu.h"
+
+/* Global control variables for rcupdate callback mechanism. */
+struct rcu_ctrlblk {
+	struct rcu_head *rcucblist;	/* List of pending callbacks (CBs). */
+	struct rcu_head **donetail;	/* ->next pointer of last "done" CB. */
+	struct rcu_head **curtail;	/* ->next pointer of last CB. */
+	unsigned long gp_seq;		/* Grace-period counter. */
+};
+
+/* Definition for rcupdate control block. */
+static struct rcu_ctrlblk rcu_ctrlblk = {
+	.donetail	= &rcu_ctrlblk.rcucblist,
+	.curtail	= &rcu_ctrlblk.rcucblist,
+	.gp_seq		= 0 - 300UL,
+};
+
+void rcu_barrier(void)
+{
+	wait_rcu_gp(call_rcu);
+}
+EXPORT_SYMBOL(rcu_barrier);
+
+/* Record an rcu quiescent state.  */
+void rcu_qs(void)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	if (rcu_ctrlblk.donetail != rcu_ctrlblk.curtail) {
+		rcu_ctrlblk.donetail = rcu_ctrlblk.curtail;
+		raise_softirq_irqoff(RCU_SOFTIRQ);
+	}
+	WRITE_ONCE(rcu_ctrlblk.gp_seq, rcu_ctrlblk.gp_seq + 2);
+	local_irq_restore(flags);
+}
+
+/*
+ * Check to see if the scheduling-clock interrupt came from an extended
+ * quiescent state, and, if so, tell RCU about it.  This function must
+ * be called from hardirq context.  It is normally called from the
+ * scheduling-clock interrupt.
+ */
+void rcu_sched_clock_irq(int user)
+{
+	if (user) {
+		rcu_qs();
+	} else if (rcu_ctrlblk.donetail != rcu_ctrlblk.curtail) {
+		set_tsk_need_resched(current);
+		set_preempt_need_resched();
+	}
+}
+
+/*
+ * Reclaim the specified callback, either by invoking it for non-kfree cases or
+ * freeing it directly (for kfree). Return true if kfreeing, false otherwise.
+ */
+static inline bool rcu_reclaim_tiny(struct rcu_head *head)
+{
+	rcu_callback_t f;
+	unsigned long offset = (unsigned long)head->func;
+
+	rcu_lock_acquire(&rcu_callback_map);
+	if (__is_kvfree_rcu_offset(offset)) {
+		trace_rcu_invoke_kvfree_callback("", head, offset);
+		kvfree((void *)head - offset);
+		rcu_lock_release(&rcu_callback_map);
+		return true;
+	}
+
+	trace_rcu_invoke_callback("", head);
+	f = head->func;
+	WRITE_ONCE(head->func, (rcu_callback_t)0L);
+	f(head);
+	rcu_lock_release(&rcu_callback_map);
+	return false;
+}
+
+/* Invoke the RCU callbacks whose grace period has elapsed.  */
+static __latent_entropy void rcu_process_callbacks(struct softirq_action *unused)
+{
+	struct rcu_head *next, *list;
+	unsigned long flags;
+
+	/* Move the ready-to-invoke callbacks to a local list. */
+	local_irq_save(flags);
+	if (rcu_ctrlblk.donetail == &rcu_ctrlblk.rcucblist) {
+		/* No callbacks ready, so just leave. */
+		local_irq_restore(flags);
+		return;
+	}
+	list = rcu_ctrlblk.rcucblist;
+	rcu_ctrlblk.rcucblist = *rcu_ctrlblk.donetail;
+	*rcu_ctrlblk.donetail = NULL;
+	if (rcu_ctrlblk.curtail == rcu_ctrlblk.donetail)
+		rcu_ctrlblk.curtail = &rcu_ctrlblk.rcucblist;
+	rcu_ctrlblk.donetail = &rcu_ctrlblk.rcucblist;
+	local_irq_restore(flags);
+
+	/* Invoke the callbacks on the local list. */
+	while (list) {
+		next = list->next;
+		prefetch(next);
+		debug_rcu_head_unqueue(list);
+		local_bh_disable();
+		rcu_reclaim_tiny(list);
+		local_bh_enable();
+		list = next;
+	}
+}
+
+/*
+ * Wait for a grace period to elapse.  But it is illegal to invoke
+ * synchronize_rcu() from within an RCU read-side critical section.
+ * Therefore, any legal call to synchronize_rcu() is a quiescent state,
+ * and so on a UP system, synchronize_rcu() need do nothing, other than
+ * let the polled APIs know that another grace period elapsed.
+ *
+ * (But Lai Jiangshan points out the benefits of doing might_sleep()
+ * to reduce latency.)
+ *
+ * Cool, huh?  (Due to Josh Triplett.)
+ */
+void synchronize_rcu(void)
+{
+	RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+			 lock_is_held(&rcu_lock_map) ||
+			 lock_is_held(&rcu_sched_lock_map),
+			 "Illegal synchronize_rcu() in RCU read-side critical section");
+	WRITE_ONCE(rcu_ctrlblk.gp_seq, rcu_ctrlblk.gp_seq + 2);
+}
+EXPORT_SYMBOL_GPL(synchronize_rcu);
+
+static void tiny_rcu_leak_callback(struct rcu_head *rhp)
+{
+}
+
+/*
+ * Post an RCU callback to be invoked after the end of an RCU grace
+ * period.  But since we have but one CPU, that would be after any
+ * quiescent state.
+ */
+void call_rcu(struct rcu_head *head, rcu_callback_t func)
+{
+	static atomic_t doublefrees;
+	unsigned long flags;
+
+	if (debug_rcu_head_queue(head)) {
+		if (atomic_inc_return(&doublefrees) < 4) {
+			pr_err("%s(): Double-freed CB %p->%pS()!!!  ", __func__, head, head->func);
+			mem_dump_obj(head);
+		}
+
+		if (!__is_kvfree_rcu_offset((unsigned long)head->func))
+			WRITE_ONCE(head->func, tiny_rcu_leak_callback);
+		return;
+	}
+
+	head->func = func;
+	head->next = NULL;
+
+	local_irq_save(flags);
+	*rcu_ctrlblk.curtail = head;
+	rcu_ctrlblk.curtail = &head->next;
+	local_irq_restore(flags);
+
+	if (unlikely(is_idle_task(current))) {
+		/* force scheduling for rcu_qs() */
+		resched_cpu(0);
+	}
+}
+EXPORT_SYMBOL_GPL(call_rcu);
+
+/*
+ * Store a grace-period-counter "cookie".  For more information,
+ * see the Tree RCU header comment.
+ */
+void get_completed_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
+{
+	rgosp->rgos_norm = RCU_GET_STATE_COMPLETED;
+}
+EXPORT_SYMBOL_GPL(get_completed_synchronize_rcu_full);
+
+/*
+ * Return a grace-period-counter "cookie".  For more information,
+ * see the Tree RCU header comment.
+ */
+unsigned long get_state_synchronize_rcu(void)
+{
+	return READ_ONCE(rcu_ctrlblk.gp_seq);
+}
+EXPORT_SYMBOL_GPL(get_state_synchronize_rcu);
+
+/*
+ * Return a grace-period-counter "cookie" and ensure that a future grace
+ * period completes.  For more information, see the Tree RCU header comment.
+ */
+unsigned long start_poll_synchronize_rcu(void)
+{
+	unsigned long gp_seq = get_state_synchronize_rcu();
+
+	if (unlikely(is_idle_task(current))) {
+		/* force scheduling for rcu_qs() */
+		resched_cpu(0);
+	}
+	return gp_seq;
+}
+EXPORT_SYMBOL_GPL(start_poll_synchronize_rcu);
+
+/*
+ * Return true if the grace period corresponding to oldstate has completed
+ * and false otherwise.  For more information, see the Tree RCU header
+ * comment.
+ */
+bool poll_state_synchronize_rcu(unsigned long oldstate)
+{
+	return oldstate == RCU_GET_STATE_COMPLETED || READ_ONCE(rcu_ctrlblk.gp_seq) != oldstate;
+}
+EXPORT_SYMBOL_GPL(poll_state_synchronize_rcu);
+
+#ifdef CONFIG_KASAN_GENERIC
+void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
+{
+	if (head) {
+		void *ptr = (void *) head - (unsigned long) func;
+
+		kasan_record_aux_stack_noalloc(ptr);
+	}
+
+	__kvfree_call_rcu(head, func);
+}
+EXPORT_SYMBOL_GPL(kvfree_call_rcu);
+#endif
+
+void __init rcu_init(void)
+{
+	open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
+	rcu_early_boot_tests();
+}
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
new file mode 100644
index 000000000..9d7464a90
--- /dev/null
+++ b/kernel/rcu/tree.c
@@ -0,0 +1,4878 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Read-Copy Update mechanism for mutual exclusion (tree-based version)
+ *
+ * Copyright IBM Corporation, 2008
+ *
+ * Authors: Dipankar Sarma <dipankar@in.ibm.com>
+ *	    Manfred Spraul <manfred@colorfullife.com>
+ *	    Paul E. McKenney <paulmck@linux.ibm.com>
+ *
+ * Based on the original work by Paul McKenney <paulmck@linux.ibm.com>
+ * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
+ *
+ * For detailed explanation of Read-Copy Update mechanism see -
+ *	Documentation/RCU
+ */
+
+#define pr_fmt(fmt) "rcu: " fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+#include <linux/rcupdate_wait.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/nmi.h>
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/export.h>
+#include <linux/completion.h>
+#include <linux/kmemleak.h>
+#include <linux/moduleparam.h>
+#include <linux/panic.h>
+#include <linux/panic_notifier.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/cpu.h>
+#include <linux/mutex.h>
+#include <linux/time.h>
+#include <linux/kernel_stat.h>
+#include <linux/wait.h>
+#include <linux/kthread.h>
+#include <uapi/linux/sched/types.h>
+#include <linux/prefetch.h>
+#include <linux/delay.h>
+#include <linux/random.h>
+#include <linux/trace_events.h>
+#include <linux/suspend.h>
+#include <linux/ftrace.h>
+#include <linux/tick.h>
+#include <linux/sysrq.h>
+#include <linux/kprobes.h>
+#include <linux/gfp.h>
+#include <linux/oom.h>
+#include <linux/smpboot.h>
+#include <linux/jiffies.h>
+#include <linux/slab.h>
+#include <linux/sched/isolation.h>
+#include <linux/sched/clock.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <linux/kasan.h>
+#include <linux/context_tracking.h>
+#include "../time/tick-internal.h"
+
+#include "tree.h"
+#include "rcu.h"
+
+#ifdef MODULE_PARAM_PREFIX
+#undef MODULE_PARAM_PREFIX
+#endif
+#define MODULE_PARAM_PREFIX "rcutree."
+
+/* Data structures. */
+
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, rcu_data) = {
+	.gpwrap = true,
+#ifdef CONFIG_RCU_NOCB_CPU
+	.cblist.flags = SEGCBLIST_RCU_CORE,
+#endif
+};
+static struct rcu_state rcu_state = {
+	.level = { &rcu_state.node[0] },
+	.gp_state = RCU_GP_IDLE,
+	.gp_seq = (0UL - 300UL) << RCU_SEQ_CTR_SHIFT,
+	.barrier_mutex = __MUTEX_INITIALIZER(rcu_state.barrier_mutex),
+	.barrier_lock = __RAW_SPIN_LOCK_UNLOCKED(rcu_state.barrier_lock),
+	.name = RCU_NAME,
+	.abbr = RCU_ABBR,
+	.exp_mutex = __MUTEX_INITIALIZER(rcu_state.exp_mutex),
+	.exp_wake_mutex = __MUTEX_INITIALIZER(rcu_state.exp_wake_mutex),
+	.ofl_lock = __ARCH_SPIN_LOCK_UNLOCKED,
+};
+
+/* Dump rcu_node combining tree at boot to verify correct setup. */
+static bool dump_tree;
+module_param(dump_tree, bool, 0444);
+/* By default, use RCU_SOFTIRQ instead of rcuc kthreads. */
+static bool use_softirq = !IS_ENABLED(CONFIG_PREEMPT_RT);
+#ifndef CONFIG_PREEMPT_RT
+module_param(use_softirq, bool, 0444);
+#endif
+/* Control rcu_node-tree auto-balancing at boot time. */
+static bool rcu_fanout_exact;
+module_param(rcu_fanout_exact, bool, 0444);
+/* Increase (but not decrease) the RCU_FANOUT_LEAF at boot time. */
+static int rcu_fanout_leaf = RCU_FANOUT_LEAF;
+module_param(rcu_fanout_leaf, int, 0444);
+int rcu_num_lvls __read_mostly = RCU_NUM_LVLS;
+/* Number of rcu_nodes at specified level. */
+int num_rcu_lvl[] = NUM_RCU_LVL_INIT;
+int rcu_num_nodes __read_mostly = NUM_RCU_NODES; /* Total # rcu_nodes in use. */
+
+/*
+ * The rcu_scheduler_active variable is initialized to the value
+ * RCU_SCHEDULER_INACTIVE and transitions RCU_SCHEDULER_INIT just before the
+ * first task is spawned.  So when this variable is RCU_SCHEDULER_INACTIVE,
+ * RCU can assume that there is but one task, allowing RCU to (for example)
+ * optimize synchronize_rcu() to a simple barrier().  When this variable
+ * is RCU_SCHEDULER_INIT, RCU must actually do all the hard work required
+ * to detect real grace periods.  This variable is also used to suppress
+ * boot-time false positives from lockdep-RCU error checking.  Finally, it
+ * transitions from RCU_SCHEDULER_INIT to RCU_SCHEDULER_RUNNING after RCU
+ * is fully initialized, including all of its kthreads having been spawned.
+ */
+int rcu_scheduler_active __read_mostly;
+EXPORT_SYMBOL_GPL(rcu_scheduler_active);
+
+/*
+ * The rcu_scheduler_fully_active variable transitions from zero to one
+ * during the early_initcall() processing, which is after the scheduler
+ * is capable of creating new tasks.  So RCU processing (for example,
+ * creating tasks for RCU priority boosting) must be delayed until after
+ * rcu_scheduler_fully_active transitions from zero to one.  We also
+ * currently delay invocation of any RCU callbacks until after this point.
+ *
+ * It might later prove better for people registering RCU callbacks during
+ * early boot to take responsibility for these callbacks, but one step at
+ * a time.
+ */
+static int rcu_scheduler_fully_active __read_mostly;
+
+static void rcu_report_qs_rnp(unsigned long mask, struct rcu_node *rnp,
+			      unsigned long gps, unsigned long flags);
+static void rcu_init_new_rnp(struct rcu_node *rnp_leaf);
+static void rcu_cleanup_dead_rnp(struct rcu_node *rnp_leaf);
+static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu);
+static void invoke_rcu_core(void);
+static void rcu_report_exp_rdp(struct rcu_data *rdp);
+static void sync_sched_exp_online_cleanup(int cpu);
+static void check_cb_ovld_locked(struct rcu_data *rdp, struct rcu_node *rnp);
+static bool rcu_rdp_is_offloaded(struct rcu_data *rdp);
+
+/*
+ * rcuc/rcub/rcuop kthread realtime priority. The "rcuop"
+ * real-time priority(enabling/disabling) is controlled by
+ * the extra CONFIG_RCU_NOCB_CPU_CB_BOOST configuration.
+ */
+static int kthread_prio = IS_ENABLED(CONFIG_RCU_BOOST) ? 1 : 0;
+module_param(kthread_prio, int, 0444);
+
+/* Delay in jiffies for grace-period initialization delays, debug only. */
+
+static int gp_preinit_delay;
+module_param(gp_preinit_delay, int, 0444);
+static int gp_init_delay;
+module_param(gp_init_delay, int, 0444);
+static int gp_cleanup_delay;
+module_param(gp_cleanup_delay, int, 0444);
+
+// Add delay to rcu_read_unlock() for strict grace periods.
+static int rcu_unlock_delay;
+#ifdef CONFIG_RCU_STRICT_GRACE_PERIOD
+module_param(rcu_unlock_delay, int, 0444);
+#endif
+
+/*
+ * This rcu parameter is runtime-read-only. It reflects
+ * a minimum allowed number of objects which can be cached
+ * per-CPU. Object size is equal to one page. This value
+ * can be changed at boot time.
+ */
+static int rcu_min_cached_objs = 5;
+module_param(rcu_min_cached_objs, int, 0444);
+
+// A page shrinker can ask for pages to be freed to make them
+// available for other parts of the system. This usually happens
+// under low memory conditions, and in that case we should also
+// defer page-cache filling for a short time period.
+//
+// The default value is 5 seconds, which is long enough to reduce
+// interference with the shrinker while it asks other systems to
+// drain their caches.
+static int rcu_delay_page_cache_fill_msec = 5000;
+module_param(rcu_delay_page_cache_fill_msec, int, 0444);
+
+/* Retrieve RCU kthreads priority for rcutorture */
+int rcu_get_gp_kthreads_prio(void)
+{
+	return kthread_prio;
+}
+EXPORT_SYMBOL_GPL(rcu_get_gp_kthreads_prio);
+
+/*
+ * Number of grace periods between delays, normalized by the duration of
+ * the delay.  The longer the delay, the more the grace periods between
+ * each delay.  The reason for this normalization is that it means that,
+ * for non-zero delays, the overall slowdown of grace periods is constant
+ * regardless of the duration of the delay.  This arrangement balances
+ * the need for long delays to increase some race probabilities with the
+ * need for fast grace periods to increase other race probabilities.
+ */
+#define PER_RCU_NODE_PERIOD 3	/* Number of grace periods between delays for debugging. */
+
+/*
+ * Compute the mask of online CPUs for the specified rcu_node structure.
+ * This will not be stable unless the rcu_node structure's ->lock is
+ * held, but the bit corresponding to the current CPU will be stable
+ * in most contexts.
+ */
+static unsigned long rcu_rnp_online_cpus(struct rcu_node *rnp)
+{
+	return READ_ONCE(rnp->qsmaskinitnext);
+}
+
+/*
+ * Is the CPU corresponding to the specified rcu_data structure online
+ * from RCU's perspective?  This perspective is given by that structure's
+ * ->qsmaskinitnext field rather than by the global cpu_online_mask.
+ */
+static bool rcu_rdp_cpu_online(struct rcu_data *rdp)
+{
+	return !!(rdp->grpmask & rcu_rnp_online_cpus(rdp->mynode));
+}
+
+/*
+ * Return true if an RCU grace period is in progress.  The READ_ONCE()s
+ * permit this function to be invoked without holding the root rcu_node
+ * structure's ->lock, but of course results can be subject to change.
+ */
+static int rcu_gp_in_progress(void)
+{
+	return rcu_seq_state(rcu_seq_current(&rcu_state.gp_seq));
+}
+
+/*
+ * Return the number of callbacks queued on the specified CPU.
+ * Handles both the nocbs and normal cases.
+ */
+static long rcu_get_n_cbs_cpu(int cpu)
+{
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+
+	if (rcu_segcblist_is_enabled(&rdp->cblist))
+		return rcu_segcblist_n_cbs(&rdp->cblist);
+	return 0;
+}
+
+void rcu_softirq_qs(void)
+{
+	rcu_qs();
+	rcu_preempt_deferred_qs(current);
+	rcu_tasks_qs(current, false);
+}
+
+/*
+ * Reset the current CPU's ->dynticks counter to indicate that the
+ * newly onlined CPU is no longer in an extended quiescent state.
+ * This will either leave the counter unchanged, or increment it
+ * to the next non-quiescent value.
+ *
+ * The non-atomic test/increment sequence works because the upper bits
+ * of the ->dynticks counter are manipulated only by the corresponding CPU,
+ * or when the corresponding CPU is offline.
+ */
+static void rcu_dynticks_eqs_online(void)
+{
+	if (ct_dynticks() & RCU_DYNTICKS_IDX)
+		return;
+	ct_state_inc(RCU_DYNTICKS_IDX);
+}
+
+/*
+ * Snapshot the ->dynticks counter with full ordering so as to allow
+ * stable comparison of this counter with past and future snapshots.
+ */
+static int rcu_dynticks_snap(int cpu)
+{
+	smp_mb();  // Fundamental RCU ordering guarantee.
+	return ct_dynticks_cpu_acquire(cpu);
+}
+
+/*
+ * Return true if the snapshot returned from rcu_dynticks_snap()
+ * indicates that RCU is in an extended quiescent state.
+ */
+static bool rcu_dynticks_in_eqs(int snap)
+{
+	return !(snap & RCU_DYNTICKS_IDX);
+}
+
+/* Return true if the specified CPU is currently idle from an RCU viewpoint.  */
+bool rcu_is_idle_cpu(int cpu)
+{
+	return rcu_dynticks_in_eqs(rcu_dynticks_snap(cpu));
+}
+
+/*
+ * Return true if the CPU corresponding to the specified rcu_data
+ * structure has spent some time in an extended quiescent state since
+ * rcu_dynticks_snap() returned the specified snapshot.
+ */
+static bool rcu_dynticks_in_eqs_since(struct rcu_data *rdp, int snap)
+{
+	return snap != rcu_dynticks_snap(rdp->cpu);
+}
+
+/*
+ * Return true if the referenced integer is zero while the specified
+ * CPU remains within a single extended quiescent state.
+ */
+bool rcu_dynticks_zero_in_eqs(int cpu, int *vp)
+{
+	int snap;
+
+	// If not quiescent, force back to earlier extended quiescent state.
+	snap = ct_dynticks_cpu(cpu) & ~RCU_DYNTICKS_IDX;
+	smp_rmb(); // Order ->dynticks and *vp reads.
+	if (READ_ONCE(*vp))
+		return false;  // Non-zero, so report failure;
+	smp_rmb(); // Order *vp read and ->dynticks re-read.
+
+	// If still in the same extended quiescent state, we are good!
+	return snap == ct_dynticks_cpu(cpu);
+}
+
+/*
+ * Let the RCU core know that this CPU has gone through the scheduler,
+ * which is a quiescent state.  This is called when the need for a
+ * quiescent state is urgent, so we burn an atomic operation and full
+ * memory barriers to let the RCU core know about it, regardless of what
+ * this CPU might (or might not) do in the near future.
+ *
+ * We inform the RCU core by emulating a zero-duration dyntick-idle period.
+ *
+ * The caller must have disabled interrupts and must not be idle.
+ */
+notrace void rcu_momentary_dyntick_idle(void)
+{
+	int seq;
+
+	raw_cpu_write(rcu_data.rcu_need_heavy_qs, false);
+	seq = ct_state_inc(2 * RCU_DYNTICKS_IDX);
+	/* It is illegal to call this from idle state. */
+	WARN_ON_ONCE(!(seq & RCU_DYNTICKS_IDX));
+	rcu_preempt_deferred_qs(current);
+}
+EXPORT_SYMBOL_GPL(rcu_momentary_dyntick_idle);
+
+/**
+ * rcu_is_cpu_rrupt_from_idle - see if 'interrupted' from idle
+ *
+ * If the current CPU is idle and running at a first-level (not nested)
+ * interrupt, or directly, from idle, return true.
+ *
+ * The caller must have at least disabled IRQs.
+ */
+static int rcu_is_cpu_rrupt_from_idle(void)
+{
+	long nesting;
+
+	/*
+	 * Usually called from the tick; but also used from smp_function_call()
+	 * for expedited grace periods. This latter can result in running from
+	 * the idle task, instead of an actual IPI.
+	 */
+	lockdep_assert_irqs_disabled();
+
+	/* Check for counter underflows */
+	RCU_LOCKDEP_WARN(ct_dynticks_nesting() < 0,
+			 "RCU dynticks_nesting counter underflow!");
+	RCU_LOCKDEP_WARN(ct_dynticks_nmi_nesting() <= 0,
+			 "RCU dynticks_nmi_nesting counter underflow/zero!");
+
+	/* Are we at first interrupt nesting level? */
+	nesting = ct_dynticks_nmi_nesting();
+	if (nesting > 1)
+		return false;
+
+	/*
+	 * If we're not in an interrupt, we must be in the idle task!
+	 */
+	WARN_ON_ONCE(!nesting && !is_idle_task(current));
+
+	/* Does CPU appear to be idle from an RCU standpoint? */
+	return ct_dynticks_nesting() == 0;
+}
+
+#define DEFAULT_RCU_BLIMIT (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD) ? 1000 : 10)
+				// Maximum callbacks per rcu_do_batch ...
+#define DEFAULT_MAX_RCU_BLIMIT 10000 // ... even during callback flood.
+static long blimit = DEFAULT_RCU_BLIMIT;
+#define DEFAULT_RCU_QHIMARK 10000 // If this many pending, ignore blimit.
+static long qhimark = DEFAULT_RCU_QHIMARK;
+#define DEFAULT_RCU_QLOMARK 100   // Once only this many pending, use blimit.
+static long qlowmark = DEFAULT_RCU_QLOMARK;
+#define DEFAULT_RCU_QOVLD_MULT 2
+#define DEFAULT_RCU_QOVLD (DEFAULT_RCU_QOVLD_MULT * DEFAULT_RCU_QHIMARK)
+static long qovld = DEFAULT_RCU_QOVLD; // If this many pending, hammer QS.
+static long qovld_calc = -1;	  // No pre-initialization lock acquisitions!
+
+module_param(blimit, long, 0444);
+module_param(qhimark, long, 0444);
+module_param(qlowmark, long, 0444);
+module_param(qovld, long, 0444);
+
+static ulong jiffies_till_first_fqs = IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD) ? 0 : ULONG_MAX;
+static ulong jiffies_till_next_fqs = ULONG_MAX;
+static bool rcu_kick_kthreads;
+static int rcu_divisor = 7;
+module_param(rcu_divisor, int, 0644);
+
+/* Force an exit from rcu_do_batch() after 3 milliseconds. */
+static long rcu_resched_ns = 3 * NSEC_PER_MSEC;
+module_param(rcu_resched_ns, long, 0644);
+
+/*
+ * How long the grace period must be before we start recruiting
+ * quiescent-state help from rcu_note_context_switch().
+ */
+static ulong jiffies_till_sched_qs = ULONG_MAX;
+module_param(jiffies_till_sched_qs, ulong, 0444);
+static ulong jiffies_to_sched_qs; /* See adjust_jiffies_till_sched_qs(). */
+module_param(jiffies_to_sched_qs, ulong, 0444); /* Display only! */
+
+/*
+ * Make sure that we give the grace-period kthread time to detect any
+ * idle CPUs before taking active measures to force quiescent states.
+ * However, don't go below 100 milliseconds, adjusted upwards for really
+ * large systems.
+ */
+static void adjust_jiffies_till_sched_qs(void)
+{
+	unsigned long j;
+
+	/* If jiffies_till_sched_qs was specified, respect the request. */
+	if (jiffies_till_sched_qs != ULONG_MAX) {
+		WRITE_ONCE(jiffies_to_sched_qs, jiffies_till_sched_qs);
+		return;
+	}
+	/* Otherwise, set to third fqs scan, but bound below on large system. */
+	j = READ_ONCE(jiffies_till_first_fqs) +
+		      2 * READ_ONCE(jiffies_till_next_fqs);
+	if (j < HZ / 10 + nr_cpu_ids / RCU_JIFFIES_FQS_DIV)
+		j = HZ / 10 + nr_cpu_ids / RCU_JIFFIES_FQS_DIV;
+	pr_info("RCU calculated value of scheduler-enlistment delay is %ld jiffies.\n", j);
+	WRITE_ONCE(jiffies_to_sched_qs, j);
+}
+
+static int param_set_first_fqs_jiffies(const char *val, const struct kernel_param *kp)
+{
+	ulong j;
+	int ret = kstrtoul(val, 0, &j);
+
+	if (!ret) {
+		WRITE_ONCE(*(ulong *)kp->arg, (j > HZ) ? HZ : j);
+		adjust_jiffies_till_sched_qs();
+	}
+	return ret;
+}
+
+static int param_set_next_fqs_jiffies(const char *val, const struct kernel_param *kp)
+{
+	ulong j;
+	int ret = kstrtoul(val, 0, &j);
+
+	if (!ret) {
+		WRITE_ONCE(*(ulong *)kp->arg, (j > HZ) ? HZ : (j ?: 1));
+		adjust_jiffies_till_sched_qs();
+	}
+	return ret;
+}
+
+static const struct kernel_param_ops first_fqs_jiffies_ops = {
+	.set = param_set_first_fqs_jiffies,
+	.get = param_get_ulong,
+};
+
+static const struct kernel_param_ops next_fqs_jiffies_ops = {
+	.set = param_set_next_fqs_jiffies,
+	.get = param_get_ulong,
+};
+
+module_param_cb(jiffies_till_first_fqs, &first_fqs_jiffies_ops, &jiffies_till_first_fqs, 0644);
+module_param_cb(jiffies_till_next_fqs, &next_fqs_jiffies_ops, &jiffies_till_next_fqs, 0644);
+module_param(rcu_kick_kthreads, bool, 0644);
+
+static void force_qs_rnp(int (*f)(struct rcu_data *rdp));
+static int rcu_pending(int user);
+
+/*
+ * Return the number of RCU GPs completed thus far for debug & stats.
+ */
+unsigned long rcu_get_gp_seq(void)
+{
+	return READ_ONCE(rcu_state.gp_seq);
+}
+EXPORT_SYMBOL_GPL(rcu_get_gp_seq);
+
+/*
+ * Return the number of RCU expedited batches completed thus far for
+ * debug & stats.  Odd numbers mean that a batch is in progress, even
+ * numbers mean idle.  The value returned will thus be roughly double
+ * the cumulative batches since boot.
+ */
+unsigned long rcu_exp_batches_completed(void)
+{
+	return rcu_state.expedited_sequence;
+}
+EXPORT_SYMBOL_GPL(rcu_exp_batches_completed);
+
+/*
+ * Return the root node of the rcu_state structure.
+ */
+static struct rcu_node *rcu_get_root(void)
+{
+	return &rcu_state.node[0];
+}
+
+/*
+ * Send along grace-period-related data for rcutorture diagnostics.
+ */
+void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
+			    unsigned long *gp_seq)
+{
+	switch (test_type) {
+	case RCU_FLAVOR:
+		*flags = READ_ONCE(rcu_state.gp_flags);
+		*gp_seq = rcu_seq_current(&rcu_state.gp_seq);
+		break;
+	default:
+		break;
+	}
+}
+EXPORT_SYMBOL_GPL(rcutorture_get_gp_data);
+
+#if defined(CONFIG_NO_HZ_FULL) && (!defined(CONFIG_GENERIC_ENTRY) || !defined(CONFIG_KVM_XFER_TO_GUEST_WORK))
+/*
+ * An empty function that will trigger a reschedule on
+ * IRQ tail once IRQs get re-enabled on userspace/guest resume.
+ */
+static void late_wakeup_func(struct irq_work *work)
+{
+}
+
+static DEFINE_PER_CPU(struct irq_work, late_wakeup_work) =
+	IRQ_WORK_INIT(late_wakeup_func);
+
+/*
+ * If either:
+ *
+ * 1) the task is about to enter in guest mode and $ARCH doesn't support KVM generic work
+ * 2) the task is about to enter in user mode and $ARCH doesn't support generic entry.
+ *
+ * In these cases the late RCU wake ups aren't supported in the resched loops and our
+ * last resort is to fire a local irq_work that will trigger a reschedule once IRQs
+ * get re-enabled again.
+ */
+noinstr void rcu_irq_work_resched(void)
+{
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
+
+	if (IS_ENABLED(CONFIG_GENERIC_ENTRY) && !(current->flags & PF_VCPU))
+		return;
+
+	if (IS_ENABLED(CONFIG_KVM_XFER_TO_GUEST_WORK) && (current->flags & PF_VCPU))
+		return;
+
+	instrumentation_begin();
+	if (do_nocb_deferred_wakeup(rdp) && need_resched()) {
+		irq_work_queue(this_cpu_ptr(&late_wakeup_work));
+	}
+	instrumentation_end();
+}
+#endif /* #if defined(CONFIG_NO_HZ_FULL) && (!defined(CONFIG_GENERIC_ENTRY) || !defined(CONFIG_KVM_XFER_TO_GUEST_WORK)) */
+
+#ifdef CONFIG_PROVE_RCU
+/**
+ * rcu_irq_exit_check_preempt - Validate that scheduling is possible
+ */
+void rcu_irq_exit_check_preempt(void)
+{
+	lockdep_assert_irqs_disabled();
+
+	RCU_LOCKDEP_WARN(ct_dynticks_nesting() <= 0,
+			 "RCU dynticks_nesting counter underflow/zero!");
+	RCU_LOCKDEP_WARN(ct_dynticks_nmi_nesting() !=
+			 DYNTICK_IRQ_NONIDLE,
+			 "Bad RCU  dynticks_nmi_nesting counter\n");
+	RCU_LOCKDEP_WARN(rcu_dynticks_curr_cpu_in_eqs(),
+			 "RCU in extended quiescent state!");
+}
+#endif /* #ifdef CONFIG_PROVE_RCU */
+
+#ifdef CONFIG_NO_HZ_FULL
+/**
+ * __rcu_irq_enter_check_tick - Enable scheduler tick on CPU if RCU needs it.
+ *
+ * The scheduler tick is not normally enabled when CPUs enter the kernel
+ * from nohz_full userspace execution.  After all, nohz_full userspace
+ * execution is an RCU quiescent state and the time executing in the kernel
+ * is quite short.  Except of course when it isn't.  And it is not hard to
+ * cause a large system to spend tens of seconds or even minutes looping
+ * in the kernel, which can cause a number of problems, include RCU CPU
+ * stall warnings.
+ *
+ * Therefore, if a nohz_full CPU fails to report a quiescent state
+ * in a timely manner, the RCU grace-period kthread sets that CPU's
+ * ->rcu_urgent_qs flag with the expectation that the next interrupt or
+ * exception will invoke this function, which will turn on the scheduler
+ * tick, which will enable RCU to detect that CPU's quiescent states,
+ * for example, due to cond_resched() calls in CONFIG_PREEMPT=n kernels.
+ * The tick will be disabled once a quiescent state is reported for
+ * this CPU.
+ *
+ * Of course, in carefully tuned systems, there might never be an
+ * interrupt or exception.  In that case, the RCU grace-period kthread
+ * will eventually cause one to happen.  However, in less carefully
+ * controlled environments, this function allows RCU to get what it
+ * needs without creating otherwise useless interruptions.
+ */
+void __rcu_irq_enter_check_tick(void)
+{
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
+
+	// If we're here from NMI there's nothing to do.
+	if (in_nmi())
+		return;
+
+	RCU_LOCKDEP_WARN(rcu_dynticks_curr_cpu_in_eqs(),
+			 "Illegal rcu_irq_enter_check_tick() from extended quiescent state");
+
+	if (!tick_nohz_full_cpu(rdp->cpu) ||
+	    !READ_ONCE(rdp->rcu_urgent_qs) ||
+	    READ_ONCE(rdp->rcu_forced_tick)) {
+		// RCU doesn't need nohz_full help from this CPU, or it is
+		// already getting that help.
+		return;
+	}
+
+	// We get here only when not in an extended quiescent state and
+	// from interrupts (as opposed to NMIs).  Therefore, (1) RCU is
+	// already watching and (2) The fact that we are in an interrupt
+	// handler and that the rcu_node lock is an irq-disabled lock
+	// prevents self-deadlock.  So we can safely recheck under the lock.
+	// Note that the nohz_full state currently cannot change.
+	raw_spin_lock_rcu_node(rdp->mynode);
+	if (rdp->rcu_urgent_qs && !rdp->rcu_forced_tick) {
+		// A nohz_full CPU is in the kernel and RCU needs a
+		// quiescent state.  Turn on the tick!
+		WRITE_ONCE(rdp->rcu_forced_tick, true);
+		tick_dep_set_cpu(rdp->cpu, TICK_DEP_BIT_RCU);
+	}
+	raw_spin_unlock_rcu_node(rdp->mynode);
+}
+NOKPROBE_SYMBOL(__rcu_irq_enter_check_tick);
+#endif /* CONFIG_NO_HZ_FULL */
+
+/*
+ * Check to see if any future non-offloaded RCU-related work will need
+ * to be done by the current CPU, even if none need be done immediately,
+ * returning 1 if so.  This function is part of the RCU implementation;
+ * it is -not- an exported member of the RCU API.  This is used by
+ * the idle-entry code to figure out whether it is safe to disable the
+ * scheduler-clock interrupt.
+ *
+ * Just check whether or not this CPU has non-offloaded RCU callbacks
+ * queued.
+ */
+int rcu_needs_cpu(void)
+{
+	return !rcu_segcblist_empty(&this_cpu_ptr(&rcu_data)->cblist) &&
+		!rcu_rdp_is_offloaded(this_cpu_ptr(&rcu_data));
+}
+
+/*
+ * If any sort of urgency was applied to the current CPU (for example,
+ * the scheduler-clock interrupt was enabled on a nohz_full CPU) in order
+ * to get to a quiescent state, disable it.
+ */
+static void rcu_disable_urgency_upon_qs(struct rcu_data *rdp)
+{
+	raw_lockdep_assert_held_rcu_node(rdp->mynode);
+	WRITE_ONCE(rdp->rcu_urgent_qs, false);
+	WRITE_ONCE(rdp->rcu_need_heavy_qs, false);
+	if (tick_nohz_full_cpu(rdp->cpu) && rdp->rcu_forced_tick) {
+		tick_dep_clear_cpu(rdp->cpu, TICK_DEP_BIT_RCU);
+		WRITE_ONCE(rdp->rcu_forced_tick, false);
+	}
+}
+
+/**
+ * rcu_is_watching - see if RCU thinks that the current CPU is not idle
+ *
+ * Return true if RCU is watching the running CPU, which means that this
+ * CPU can safely enter RCU read-side critical sections.  In other words,
+ * if the current CPU is not in its idle loop or is in an interrupt or
+ * NMI handler, return true.
+ *
+ * Make notrace because it can be called by the internal functions of
+ * ftrace, and making this notrace removes unnecessary recursion calls.
+ */
+notrace bool rcu_is_watching(void)
+{
+	bool ret;
+
+	preempt_disable_notrace();
+	ret = !rcu_dynticks_curr_cpu_in_eqs();
+	preempt_enable_notrace();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rcu_is_watching);
+
+/*
+ * If a holdout task is actually running, request an urgent quiescent
+ * state from its CPU.  This is unsynchronized, so migrations can cause
+ * the request to go to the wrong CPU.  Which is OK, all that will happen
+ * is that the CPU's next context switch will be a bit slower and next
+ * time around this task will generate another request.
+ */
+void rcu_request_urgent_qs_task(struct task_struct *t)
+{
+	int cpu;
+
+	barrier();
+	cpu = task_cpu(t);
+	if (!task_curr(t))
+		return; /* This task is not running on that CPU. */
+	smp_store_release(per_cpu_ptr(&rcu_data.rcu_urgent_qs, cpu), true);
+}
+
+#if defined(CONFIG_PROVE_RCU) && defined(CONFIG_HOTPLUG_CPU)
+
+/*
+ * Is the current CPU online as far as RCU is concerned?
+ *
+ * Disable preemption to avoid false positives that could otherwise
+ * happen due to the current CPU number being sampled, this task being
+ * preempted, its old CPU being taken offline, resuming on some other CPU,
+ * then determining that its old CPU is now offline.
+ *
+ * Disable checking if in an NMI handler because we cannot safely
+ * report errors from NMI handlers anyway.  In addition, it is OK to use
+ * RCU on an offline processor during initial boot, hence the check for
+ * rcu_scheduler_fully_active.
+ */
+bool rcu_lockdep_current_cpu_online(void)
+{
+	struct rcu_data *rdp;
+	bool ret = false;
+
+	if (in_nmi() || !rcu_scheduler_fully_active)
+		return true;
+	preempt_disable_notrace();
+	rdp = this_cpu_ptr(&rcu_data);
+	/*
+	 * Strictly, we care here about the case where the current CPU is
+	 * in rcu_cpu_starting() and thus has an excuse for rdp->grpmask
+	 * not being up to date. So arch_spin_is_locked() might have a
+	 * false positive if it's held by some *other* CPU, but that's
+	 * OK because that just means a false *negative* on the warning.
+	 */
+	if (rcu_rdp_cpu_online(rdp) || arch_spin_is_locked(&rcu_state.ofl_lock))
+		ret = true;
+	preempt_enable_notrace();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rcu_lockdep_current_cpu_online);
+
+#endif /* #if defined(CONFIG_PROVE_RCU) && defined(CONFIG_HOTPLUG_CPU) */
+
+/*
+ * When trying to report a quiescent state on behalf of some other CPU,
+ * it is our responsibility to check for and handle potential overflow
+ * of the rcu_node ->gp_seq counter with respect to the rcu_data counters.
+ * After all, the CPU might be in deep idle state, and thus executing no
+ * code whatsoever.
+ */
+static void rcu_gpnum_ovf(struct rcu_node *rnp, struct rcu_data *rdp)
+{
+	raw_lockdep_assert_held_rcu_node(rnp);
+	if (ULONG_CMP_LT(rcu_seq_current(&rdp->gp_seq) + ULONG_MAX / 4,
+			 rnp->gp_seq))
+		WRITE_ONCE(rdp->gpwrap, true);
+	if (ULONG_CMP_LT(rdp->rcu_iw_gp_seq + ULONG_MAX / 4, rnp->gp_seq))
+		rdp->rcu_iw_gp_seq = rnp->gp_seq + ULONG_MAX / 4;
+}
+
+/*
+ * Snapshot the specified CPU's dynticks counter so that we can later
+ * credit them with an implicit quiescent state.  Return 1 if this CPU
+ * is in dynticks idle mode, which is an extended quiescent state.
+ */
+static int dyntick_save_progress_counter(struct rcu_data *rdp)
+{
+	rdp->dynticks_snap = rcu_dynticks_snap(rdp->cpu);
+	if (rcu_dynticks_in_eqs(rdp->dynticks_snap)) {
+		trace_rcu_fqs(rcu_state.name, rdp->gp_seq, rdp->cpu, TPS("dti"));
+		rcu_gpnum_ovf(rdp->mynode, rdp);
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * Return true if the specified CPU has passed through a quiescent
+ * state by virtue of being in or having passed through an dynticks
+ * idle state since the last call to dyntick_save_progress_counter()
+ * for this same CPU, or by virtue of having been offline.
+ */
+static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
+{
+	unsigned long jtsq;
+	struct rcu_node *rnp = rdp->mynode;
+
+	/*
+	 * If the CPU passed through or entered a dynticks idle phase with
+	 * no active irq/NMI handlers, then we can safely pretend that the CPU
+	 * already acknowledged the request to pass through a quiescent
+	 * state.  Either way, that CPU cannot possibly be in an RCU
+	 * read-side critical section that started before the beginning
+	 * of the current RCU grace period.
+	 */
+	if (rcu_dynticks_in_eqs_since(rdp, rdp->dynticks_snap)) {
+		trace_rcu_fqs(rcu_state.name, rdp->gp_seq, rdp->cpu, TPS("dti"));
+		rcu_gpnum_ovf(rnp, rdp);
+		return 1;
+	}
+
+	/*
+	 * Complain if a CPU that is considered to be offline from RCU's
+	 * perspective has not yet reported a quiescent state.  After all,
+	 * the offline CPU should have reported a quiescent state during
+	 * the CPU-offline process, or, failing that, by rcu_gp_init()
+	 * if it ran concurrently with either the CPU going offline or the
+	 * last task on a leaf rcu_node structure exiting its RCU read-side
+	 * critical section while all CPUs corresponding to that structure
+	 * are offline.  This added warning detects bugs in any of these
+	 * code paths.
+	 *
+	 * The rcu_node structure's ->lock is held here, which excludes
+	 * the relevant portions the CPU-hotplug code, the grace-period
+	 * initialization code, and the rcu_read_unlock() code paths.
+	 *
+	 * For more detail, please refer to the "Hotplug CPU" section
+	 * of RCU's Requirements documentation.
+	 */
+	if (WARN_ON_ONCE(!rcu_rdp_cpu_online(rdp))) {
+		struct rcu_node *rnp1;
+
+		pr_info("%s: grp: %d-%d level: %d ->gp_seq %ld ->completedqs %ld\n",
+			__func__, rnp->grplo, rnp->grphi, rnp->level,
+			(long)rnp->gp_seq, (long)rnp->completedqs);
+		for (rnp1 = rnp; rnp1; rnp1 = rnp1->parent)
+			pr_info("%s: %d:%d ->qsmask %#lx ->qsmaskinit %#lx ->qsmaskinitnext %#lx ->rcu_gp_init_mask %#lx\n",
+				__func__, rnp1->grplo, rnp1->grphi, rnp1->qsmask, rnp1->qsmaskinit, rnp1->qsmaskinitnext, rnp1->rcu_gp_init_mask);
+		pr_info("%s %d: %c online: %ld(%d) offline: %ld(%d)\n",
+			__func__, rdp->cpu, ".o"[rcu_rdp_cpu_online(rdp)],
+			(long)rdp->rcu_onl_gp_seq, rdp->rcu_onl_gp_flags,
+			(long)rdp->rcu_ofl_gp_seq, rdp->rcu_ofl_gp_flags);
+		return 1; /* Break things loose after complaining. */
+	}
+
+	/*
+	 * A CPU running for an extended time within the kernel can
+	 * delay RCU grace periods: (1) At age jiffies_to_sched_qs,
+	 * set .rcu_urgent_qs, (2) At age 2*jiffies_to_sched_qs, set
+	 * both .rcu_need_heavy_qs and .rcu_urgent_qs.  Note that the
+	 * unsynchronized assignments to the per-CPU rcu_need_heavy_qs
+	 * variable are safe because the assignments are repeated if this
+	 * CPU failed to pass through a quiescent state.  This code
+	 * also checks .jiffies_resched in case jiffies_to_sched_qs
+	 * is set way high.
+	 */
+	jtsq = READ_ONCE(jiffies_to_sched_qs);
+	if (!READ_ONCE(rdp->rcu_need_heavy_qs) &&
+	    (time_after(jiffies, rcu_state.gp_start + jtsq * 2) ||
+	     time_after(jiffies, rcu_state.jiffies_resched) ||
+	     rcu_state.cbovld)) {
+		WRITE_ONCE(rdp->rcu_need_heavy_qs, true);
+		/* Store rcu_need_heavy_qs before rcu_urgent_qs. */
+		smp_store_release(&rdp->rcu_urgent_qs, true);
+	} else if (time_after(jiffies, rcu_state.gp_start + jtsq)) {
+		WRITE_ONCE(rdp->rcu_urgent_qs, true);
+	}
+
+	/*
+	 * NO_HZ_FULL CPUs can run in-kernel without rcu_sched_clock_irq!
+	 * The above code handles this, but only for straight cond_resched().
+	 * And some in-kernel loops check need_resched() before calling
+	 * cond_resched(), which defeats the above code for CPUs that are
+	 * running in-kernel with scheduling-clock interrupts disabled.
+	 * So hit them over the head with the resched_cpu() hammer!
+	 */
+	if (tick_nohz_full_cpu(rdp->cpu) &&
+	    (time_after(jiffies, READ_ONCE(rdp->last_fqs_resched) + jtsq * 3) ||
+	     rcu_state.cbovld)) {
+		WRITE_ONCE(rdp->rcu_urgent_qs, true);
+		resched_cpu(rdp->cpu);
+		WRITE_ONCE(rdp->last_fqs_resched, jiffies);
+	}
+
+	/*
+	 * If more than halfway to RCU CPU stall-warning time, invoke
+	 * resched_cpu() more frequently to try to loosen things up a bit.
+	 * Also check to see if the CPU is getting hammered with interrupts,
+	 * but only once per grace period, just to keep the IPIs down to
+	 * a dull roar.
+	 */
+	if (time_after(jiffies, rcu_state.jiffies_resched)) {
+		if (time_after(jiffies,
+			       READ_ONCE(rdp->last_fqs_resched) + jtsq)) {
+			resched_cpu(rdp->cpu);
+			WRITE_ONCE(rdp->last_fqs_resched, jiffies);
+		}
+		if (IS_ENABLED(CONFIG_IRQ_WORK) &&
+		    !rdp->rcu_iw_pending && rdp->rcu_iw_gp_seq != rnp->gp_seq &&
+		    (rnp->ffmask & rdp->grpmask)) {
+			rdp->rcu_iw_pending = true;
+			rdp->rcu_iw_gp_seq = rnp->gp_seq;
+			irq_work_queue_on(&rdp->rcu_iw, rdp->cpu);
+		}
+	}
+
+	return 0;
+}
+
+/* Trace-event wrapper function for trace_rcu_future_grace_period.  */
+static void trace_rcu_this_gp(struct rcu_node *rnp, struct rcu_data *rdp,
+			      unsigned long gp_seq_req, const char *s)
+{
+	trace_rcu_future_grace_period(rcu_state.name, READ_ONCE(rnp->gp_seq),
+				      gp_seq_req, rnp->level,
+				      rnp->grplo, rnp->grphi, s);
+}
+
+/*
+ * rcu_start_this_gp - Request the start of a particular grace period
+ * @rnp_start: The leaf node of the CPU from which to start.
+ * @rdp: The rcu_data corresponding to the CPU from which to start.
+ * @gp_seq_req: The gp_seq of the grace period to start.
+ *
+ * Start the specified grace period, as needed to handle newly arrived
+ * callbacks.  The required future grace periods are recorded in each
+ * rcu_node structure's ->gp_seq_needed field.  Returns true if there
+ * is reason to awaken the grace-period kthread.
+ *
+ * The caller must hold the specified rcu_node structure's ->lock, which
+ * is why the caller is responsible for waking the grace-period kthread.
+ *
+ * Returns true if the GP thread needs to be awakened else false.
+ */
+static bool rcu_start_this_gp(struct rcu_node *rnp_start, struct rcu_data *rdp,
+			      unsigned long gp_seq_req)
+{
+	bool ret = false;
+	struct rcu_node *rnp;
+
+	/*
+	 * Use funnel locking to either acquire the root rcu_node
+	 * structure's lock or bail out if the need for this grace period
+	 * has already been recorded -- or if that grace period has in
+	 * fact already started.  If there is already a grace period in
+	 * progress in a non-leaf node, no recording is needed because the
+	 * end of the grace period will scan the leaf rcu_node structures.
+	 * Note that rnp_start->lock must not be released.
+	 */
+	raw_lockdep_assert_held_rcu_node(rnp_start);
+	trace_rcu_this_gp(rnp_start, rdp, gp_seq_req, TPS("Startleaf"));
+	for (rnp = rnp_start; 1; rnp = rnp->parent) {
+		if (rnp != rnp_start)
+			raw_spin_lock_rcu_node(rnp);
+		if (ULONG_CMP_GE(rnp->gp_seq_needed, gp_seq_req) ||
+		    rcu_seq_started(&rnp->gp_seq, gp_seq_req) ||
+		    (rnp != rnp_start &&
+		     rcu_seq_state(rcu_seq_current(&rnp->gp_seq)))) {
+			trace_rcu_this_gp(rnp, rdp, gp_seq_req,
+					  TPS("Prestarted"));
+			goto unlock_out;
+		}
+		WRITE_ONCE(rnp->gp_seq_needed, gp_seq_req);
+		if (rcu_seq_state(rcu_seq_current(&rnp->gp_seq))) {
+			/*
+			 * We just marked the leaf or internal node, and a
+			 * grace period is in progress, which means that
+			 * rcu_gp_cleanup() will see the marking.  Bail to
+			 * reduce contention.
+			 */
+			trace_rcu_this_gp(rnp_start, rdp, gp_seq_req,
+					  TPS("Startedleaf"));
+			goto unlock_out;
+		}
+		if (rnp != rnp_start && rnp->parent != NULL)
+			raw_spin_unlock_rcu_node(rnp);
+		if (!rnp->parent)
+			break;  /* At root, and perhaps also leaf. */
+	}
+
+	/* If GP already in progress, just leave, otherwise start one. */
+	if (rcu_gp_in_progress()) {
+		trace_rcu_this_gp(rnp, rdp, gp_seq_req, TPS("Startedleafroot"));
+		goto unlock_out;
+	}
+	trace_rcu_this_gp(rnp, rdp, gp_seq_req, TPS("Startedroot"));
+	WRITE_ONCE(rcu_state.gp_flags, rcu_state.gp_flags | RCU_GP_FLAG_INIT);
+	WRITE_ONCE(rcu_state.gp_req_activity, jiffies);
+	if (!READ_ONCE(rcu_state.gp_kthread)) {
+		trace_rcu_this_gp(rnp, rdp, gp_seq_req, TPS("NoGPkthread"));
+		goto unlock_out;
+	}
+	trace_rcu_grace_period(rcu_state.name, data_race(rcu_state.gp_seq), TPS("newreq"));
+	ret = true;  /* Caller must wake GP kthread. */
+unlock_out:
+	/* Push furthest requested GP to leaf node and rcu_data structure. */
+	if (ULONG_CMP_LT(gp_seq_req, rnp->gp_seq_needed)) {
+		WRITE_ONCE(rnp_start->gp_seq_needed, rnp->gp_seq_needed);
+		WRITE_ONCE(rdp->gp_seq_needed, rnp->gp_seq_needed);
+	}
+	if (rnp != rnp_start)
+		raw_spin_unlock_rcu_node(rnp);
+	return ret;
+}
+
+/*
+ * Clean up any old requests for the just-ended grace period.  Also return
+ * whether any additional grace periods have been requested.
+ */
+static bool rcu_future_gp_cleanup(struct rcu_node *rnp)
+{
+	bool needmore;
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
+
+	needmore = ULONG_CMP_LT(rnp->gp_seq, rnp->gp_seq_needed);
+	if (!needmore)
+		rnp->gp_seq_needed = rnp->gp_seq; /* Avoid counter wrap. */
+	trace_rcu_this_gp(rnp, rdp, rnp->gp_seq,
+			  needmore ? TPS("CleanupMore") : TPS("Cleanup"));
+	return needmore;
+}
+
+static void swake_up_one_online_ipi(void *arg)
+{
+	struct swait_queue_head *wqh = arg;
+
+	swake_up_one(wqh);
+}
+
+static void swake_up_one_online(struct swait_queue_head *wqh)
+{
+	int cpu = get_cpu();
+
+	/*
+	 * If called from rcutree_report_cpu_starting(), wake up
+	 * is dangerous that late in the CPU-down hotplug process. The
+	 * scheduler might queue an ignored hrtimer. Defer the wake up
+	 * to an online CPU instead.
+	 */
+	if (unlikely(cpu_is_offline(cpu))) {
+		int target;
+
+		target = cpumask_any_and(housekeeping_cpumask(HK_TYPE_RCU),
+					 cpu_online_mask);
+
+		smp_call_function_single(target, swake_up_one_online_ipi,
+					 wqh, 0);
+		put_cpu();
+	} else {
+		put_cpu();
+		swake_up_one(wqh);
+	}
+}
+
+/*
+ * Awaken the grace-period kthread.  Don't do a self-awaken (unless in an
+ * interrupt or softirq handler, in which case we just might immediately
+ * sleep upon return, resulting in a grace-period hang), and don't bother
+ * awakening when there is nothing for the grace-period kthread to do
+ * (as in several CPUs raced to awaken, we lost), and finally don't try
+ * to awaken a kthread that has not yet been created.  If all those checks
+ * are passed, track some debug information and awaken.
+ *
+ * So why do the self-wakeup when in an interrupt or softirq handler
+ * in the grace-period kthread's context?  Because the kthread might have
+ * been interrupted just as it was going to sleep, and just after the final
+ * pre-sleep check of the awaken condition.  In this case, a wakeup really
+ * is required, and is therefore supplied.
+ */
+static void rcu_gp_kthread_wake(void)
+{
+	struct task_struct *t = READ_ONCE(rcu_state.gp_kthread);
+
+	if ((current == t && !in_hardirq() && !in_serving_softirq()) ||
+	    !READ_ONCE(rcu_state.gp_flags) || !t)
+		return;
+	WRITE_ONCE(rcu_state.gp_wake_time, jiffies);
+	WRITE_ONCE(rcu_state.gp_wake_seq, READ_ONCE(rcu_state.gp_seq));
+	swake_up_one_online(&rcu_state.gp_wq);
+}
+
+/*
+ * If there is room, assign a ->gp_seq number to any callbacks on this
+ * CPU that have not already been assigned.  Also accelerate any callbacks
+ * that were previously assigned a ->gp_seq number that has since proven
+ * to be too conservative, which can happen if callbacks get assigned a
+ * ->gp_seq number while RCU is idle, but with reference to a non-root
+ * rcu_node structure.  This function is idempotent, so it does not hurt
+ * to call it repeatedly.  Returns an flag saying that we should awaken
+ * the RCU grace-period kthread.
+ *
+ * The caller must hold rnp->lock with interrupts disabled.
+ */
+static bool rcu_accelerate_cbs(struct rcu_node *rnp, struct rcu_data *rdp)
+{
+	unsigned long gp_seq_req;
+	bool ret = false;
+
+	rcu_lockdep_assert_cblist_protected(rdp);
+	raw_lockdep_assert_held_rcu_node(rnp);
+
+	/* If no pending (not yet ready to invoke) callbacks, nothing to do. */
+	if (!rcu_segcblist_pend_cbs(&rdp->cblist))
+		return false;
+
+	trace_rcu_segcb_stats(&rdp->cblist, TPS("SegCbPreAcc"));
+
+	/*
+	 * Callbacks are often registered with incomplete grace-period
+	 * information.  Something about the fact that getting exact
+	 * information requires acquiring a global lock...  RCU therefore
+	 * makes a conservative estimate of the grace period number at which
+	 * a given callback will become ready to invoke.	The following
+	 * code checks this estimate and improves it when possible, thus
+	 * accelerating callback invocation to an earlier grace-period
+	 * number.
+	 */
+	gp_seq_req = rcu_seq_snap(&rcu_state.gp_seq);
+	if (rcu_segcblist_accelerate(&rdp->cblist, gp_seq_req))
+		ret = rcu_start_this_gp(rnp, rdp, gp_seq_req);
+
+	/* Trace depending on how much we were able to accelerate. */
+	if (rcu_segcblist_restempty(&rdp->cblist, RCU_WAIT_TAIL))
+		trace_rcu_grace_period(rcu_state.name, gp_seq_req, TPS("AccWaitCB"));
+	else
+		trace_rcu_grace_period(rcu_state.name, gp_seq_req, TPS("AccReadyCB"));
+
+	trace_rcu_segcb_stats(&rdp->cblist, TPS("SegCbPostAcc"));
+
+	return ret;
+}
+
+/*
+ * Similar to rcu_accelerate_cbs(), but does not require that the leaf
+ * rcu_node structure's ->lock be held.  It consults the cached value
+ * of ->gp_seq_needed in the rcu_data structure, and if that indicates
+ * that a new grace-period request be made, invokes rcu_accelerate_cbs()
+ * while holding the leaf rcu_node structure's ->lock.
+ */
+static void rcu_accelerate_cbs_unlocked(struct rcu_node *rnp,
+					struct rcu_data *rdp)
+{
+	unsigned long c;
+	bool needwake;
+
+	rcu_lockdep_assert_cblist_protected(rdp);
+	c = rcu_seq_snap(&rcu_state.gp_seq);
+	if (!READ_ONCE(rdp->gpwrap) && ULONG_CMP_GE(rdp->gp_seq_needed, c)) {
+		/* Old request still live, so mark recent callbacks. */
+		(void)rcu_segcblist_accelerate(&rdp->cblist, c);
+		return;
+	}
+	raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
+	needwake = rcu_accelerate_cbs(rnp, rdp);
+	raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */
+	if (needwake)
+		rcu_gp_kthread_wake();
+}
+
+/*
+ * Move any callbacks whose grace period has completed to the
+ * RCU_DONE_TAIL sublist, then compact the remaining sublists and
+ * assign ->gp_seq numbers to any callbacks in the RCU_NEXT_TAIL
+ * sublist.  This function is idempotent, so it does not hurt to
+ * invoke it repeatedly.  As long as it is not invoked -too- often...
+ * Returns true if the RCU grace-period kthread needs to be awakened.
+ *
+ * The caller must hold rnp->lock with interrupts disabled.
+ */
+static bool rcu_advance_cbs(struct rcu_node *rnp, struct rcu_data *rdp)
+{
+	rcu_lockdep_assert_cblist_protected(rdp);
+	raw_lockdep_assert_held_rcu_node(rnp);
+
+	/* If no pending (not yet ready to invoke) callbacks, nothing to do. */
+	if (!rcu_segcblist_pend_cbs(&rdp->cblist))
+		return false;
+
+	/*
+	 * Find all callbacks whose ->gp_seq numbers indicate that they
+	 * are ready to invoke, and put them into the RCU_DONE_TAIL sublist.
+	 */
+	rcu_segcblist_advance(&rdp->cblist, rnp->gp_seq);
+
+	/* Classify any remaining callbacks. */
+	return rcu_accelerate_cbs(rnp, rdp);
+}
+
+/*
+ * Move and classify callbacks, but only if doing so won't require
+ * that the RCU grace-period kthread be awakened.
+ */
+static void __maybe_unused rcu_advance_cbs_nowake(struct rcu_node *rnp,
+						  struct rcu_data *rdp)
+{
+	rcu_lockdep_assert_cblist_protected(rdp);
+	if (!rcu_seq_state(rcu_seq_current(&rnp->gp_seq)) || !raw_spin_trylock_rcu_node(rnp))
+		return;
+	// The grace period cannot end while we hold the rcu_node lock.
+	if (rcu_seq_state(rcu_seq_current(&rnp->gp_seq)))
+		WARN_ON_ONCE(rcu_advance_cbs(rnp, rdp));
+	raw_spin_unlock_rcu_node(rnp);
+}
+
+/*
+ * In CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels, attempt to generate a
+ * quiescent state.  This is intended to be invoked when the CPU notices
+ * a new grace period.
+ */
+static void rcu_strict_gp_check_qs(void)
+{
+	if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD)) {
+		rcu_read_lock();
+		rcu_read_unlock();
+	}
+}
+
+/*
+ * Update CPU-local rcu_data state to record the beginnings and ends of
+ * grace periods.  The caller must hold the ->lock of the leaf rcu_node
+ * structure corresponding to the current CPU, and must have irqs disabled.
+ * Returns true if the grace-period kthread needs to be awakened.
+ */
+static bool __note_gp_changes(struct rcu_node *rnp, struct rcu_data *rdp)
+{
+	bool ret = false;
+	bool need_qs;
+	const bool offloaded = rcu_rdp_is_offloaded(rdp);
+
+	raw_lockdep_assert_held_rcu_node(rnp);
+
+	if (rdp->gp_seq == rnp->gp_seq)
+		return false; /* Nothing to do. */
+
+	/* Handle the ends of any preceding grace periods first. */
+	if (rcu_seq_completed_gp(rdp->gp_seq, rnp->gp_seq) ||
+	    unlikely(READ_ONCE(rdp->gpwrap))) {
+		if (!offloaded)
+			ret = rcu_advance_cbs(rnp, rdp); /* Advance CBs. */
+		rdp->core_needs_qs = false;
+		trace_rcu_grace_period(rcu_state.name, rdp->gp_seq, TPS("cpuend"));
+	} else {
+		if (!offloaded)
+			ret = rcu_accelerate_cbs(rnp, rdp); /* Recent CBs. */
+		if (rdp->core_needs_qs)
+			rdp->core_needs_qs = !!(rnp->qsmask & rdp->grpmask);
+	}
+
+	/* Now handle the beginnings of any new-to-this-CPU grace periods. */
+	if (rcu_seq_new_gp(rdp->gp_seq, rnp->gp_seq) ||
+	    unlikely(READ_ONCE(rdp->gpwrap))) {
+		/*
+		 * If the current grace period is waiting for this CPU,
+		 * set up to detect a quiescent state, otherwise don't
+		 * go looking for one.
+		 */
+		trace_rcu_grace_period(rcu_state.name, rnp->gp_seq, TPS("cpustart"));
+		need_qs = !!(rnp->qsmask & rdp->grpmask);
+		rdp->cpu_no_qs.b.norm = need_qs;
+		rdp->core_needs_qs = need_qs;
+		zero_cpu_stall_ticks(rdp);
+	}
+	rdp->gp_seq = rnp->gp_seq;  /* Remember new grace-period state. */
+	if (ULONG_CMP_LT(rdp->gp_seq_needed, rnp->gp_seq_needed) || rdp->gpwrap)
+		WRITE_ONCE(rdp->gp_seq_needed, rnp->gp_seq_needed);
+	if (IS_ENABLED(CONFIG_PROVE_RCU) && READ_ONCE(rdp->gpwrap))
+		WRITE_ONCE(rdp->last_sched_clock, jiffies);
+	WRITE_ONCE(rdp->gpwrap, false);
+	rcu_gpnum_ovf(rnp, rdp);
+	return ret;
+}
+
+static void note_gp_changes(struct rcu_data *rdp)
+{
+	unsigned long flags;
+	bool needwake;
+	struct rcu_node *rnp;
+
+	local_irq_save(flags);
+	rnp = rdp->mynode;
+	if ((rdp->gp_seq == rcu_seq_current(&rnp->gp_seq) &&
+	     !unlikely(READ_ONCE(rdp->gpwrap))) || /* w/out lock. */
+	    !raw_spin_trylock_rcu_node(rnp)) { /* irqs already off, so later. */
+		local_irq_restore(flags);
+		return;
+	}
+	needwake = __note_gp_changes(rnp, rdp);
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	rcu_strict_gp_check_qs();
+	if (needwake)
+		rcu_gp_kthread_wake();
+}
+
+static atomic_t *rcu_gp_slow_suppress;
+
+/* Register a counter to suppress debugging grace-period delays. */
+void rcu_gp_slow_register(atomic_t *rgssp)
+{
+	WARN_ON_ONCE(rcu_gp_slow_suppress);
+
+	WRITE_ONCE(rcu_gp_slow_suppress, rgssp);
+}
+EXPORT_SYMBOL_GPL(rcu_gp_slow_register);
+
+/* Unregister a counter, with NULL for not caring which. */
+void rcu_gp_slow_unregister(atomic_t *rgssp)
+{
+	WARN_ON_ONCE(rgssp && rgssp != rcu_gp_slow_suppress);
+
+	WRITE_ONCE(rcu_gp_slow_suppress, NULL);
+}
+EXPORT_SYMBOL_GPL(rcu_gp_slow_unregister);
+
+static bool rcu_gp_slow_is_suppressed(void)
+{
+	atomic_t *rgssp = READ_ONCE(rcu_gp_slow_suppress);
+
+	return rgssp && atomic_read(rgssp);
+}
+
+static void rcu_gp_slow(int delay)
+{
+	if (!rcu_gp_slow_is_suppressed() && delay > 0 &&
+	    !(rcu_seq_ctr(rcu_state.gp_seq) % (rcu_num_nodes * PER_RCU_NODE_PERIOD * delay)))
+		schedule_timeout_idle(delay);
+}
+
+static unsigned long sleep_duration;
+
+/* Allow rcutorture to stall the grace-period kthread. */
+void rcu_gp_set_torture_wait(int duration)
+{
+	if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST) && duration > 0)
+		WRITE_ONCE(sleep_duration, duration);
+}
+EXPORT_SYMBOL_GPL(rcu_gp_set_torture_wait);
+
+/* Actually implement the aforementioned wait. */
+static void rcu_gp_torture_wait(void)
+{
+	unsigned long duration;
+
+	if (!IS_ENABLED(CONFIG_RCU_TORTURE_TEST))
+		return;
+	duration = xchg(&sleep_duration, 0UL);
+	if (duration > 0) {
+		pr_alert("%s: Waiting %lu jiffies\n", __func__, duration);
+		schedule_timeout_idle(duration);
+		pr_alert("%s: Wait complete\n", __func__);
+	}
+}
+
+/*
+ * Handler for on_each_cpu() to invoke the target CPU's RCU core
+ * processing.
+ */
+static void rcu_strict_gp_boundary(void *unused)
+{
+	invoke_rcu_core();
+}
+
+// Has rcu_init() been invoked?  This is used (for example) to determine
+// whether spinlocks may be acquired safely.
+static bool rcu_init_invoked(void)
+{
+	return !!rcu_state.n_online_cpus;
+}
+
+// Make the polled API aware of the beginning of a grace period.
+static void rcu_poll_gp_seq_start(unsigned long *snap)
+{
+	struct rcu_node *rnp = rcu_get_root();
+
+	if (rcu_init_invoked())
+		raw_lockdep_assert_held_rcu_node(rnp);
+
+	// If RCU was idle, note beginning of GP.
+	if (!rcu_seq_state(rcu_state.gp_seq_polled))
+		rcu_seq_start(&rcu_state.gp_seq_polled);
+
+	// Either way, record current state.
+	*snap = rcu_state.gp_seq_polled;
+}
+
+// Make the polled API aware of the end of a grace period.
+static void rcu_poll_gp_seq_end(unsigned long *snap)
+{
+	struct rcu_node *rnp = rcu_get_root();
+
+	if (rcu_init_invoked())
+		raw_lockdep_assert_held_rcu_node(rnp);
+
+	// If the previously noted GP is still in effect, record the
+	// end of that GP.  Either way, zero counter to avoid counter-wrap
+	// problems.
+	if (*snap && *snap == rcu_state.gp_seq_polled) {
+		rcu_seq_end(&rcu_state.gp_seq_polled);
+		rcu_state.gp_seq_polled_snap = 0;
+		rcu_state.gp_seq_polled_exp_snap = 0;
+	} else {
+		*snap = 0;
+	}
+}
+
+// Make the polled API aware of the beginning of a grace period, but
+// where caller does not hold the root rcu_node structure's lock.
+static void rcu_poll_gp_seq_start_unlocked(unsigned long *snap)
+{
+	unsigned long flags;
+	struct rcu_node *rnp = rcu_get_root();
+
+	if (rcu_init_invoked()) {
+		lockdep_assert_irqs_enabled();
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	}
+	rcu_poll_gp_seq_start(snap);
+	if (rcu_init_invoked())
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+}
+
+// Make the polled API aware of the end of a grace period, but where
+// caller does not hold the root rcu_node structure's lock.
+static void rcu_poll_gp_seq_end_unlocked(unsigned long *snap)
+{
+	unsigned long flags;
+	struct rcu_node *rnp = rcu_get_root();
+
+	if (rcu_init_invoked()) {
+		lockdep_assert_irqs_enabled();
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	}
+	rcu_poll_gp_seq_end(snap);
+	if (rcu_init_invoked())
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+}
+
+/*
+ * Initialize a new grace period.  Return false if no grace period required.
+ */
+static noinline_for_stack bool rcu_gp_init(void)
+{
+	unsigned long flags;
+	unsigned long oldmask;
+	unsigned long mask;
+	struct rcu_data *rdp;
+	struct rcu_node *rnp = rcu_get_root();
+
+	WRITE_ONCE(rcu_state.gp_activity, jiffies);
+	raw_spin_lock_irq_rcu_node(rnp);
+	if (!READ_ONCE(rcu_state.gp_flags)) {
+		/* Spurious wakeup, tell caller to go back to sleep.  */
+		raw_spin_unlock_irq_rcu_node(rnp);
+		return false;
+	}
+	WRITE_ONCE(rcu_state.gp_flags, 0); /* Clear all flags: New GP. */
+
+	if (WARN_ON_ONCE(rcu_gp_in_progress())) {
+		/*
+		 * Grace period already in progress, don't start another.
+		 * Not supposed to be able to happen.
+		 */
+		raw_spin_unlock_irq_rcu_node(rnp);
+		return false;
+	}
+
+	/* Advance to a new grace period and initialize state. */
+	record_gp_stall_check_time();
+	/* Record GP times before starting GP, hence rcu_seq_start(). */
+	rcu_seq_start(&rcu_state.gp_seq);
+	ASSERT_EXCLUSIVE_WRITER(rcu_state.gp_seq);
+	trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq, TPS("start"));
+	rcu_poll_gp_seq_start(&rcu_state.gp_seq_polled_snap);
+	raw_spin_unlock_irq_rcu_node(rnp);
+
+	/*
+	 * Apply per-leaf buffered online and offline operations to
+	 * the rcu_node tree. Note that this new grace period need not
+	 * wait for subsequent online CPUs, and that RCU hooks in the CPU
+	 * offlining path, when combined with checks in this function,
+	 * will handle CPUs that are currently going offline or that will
+	 * go offline later.  Please also refer to "Hotplug CPU" section
+	 * of RCU's Requirements documentation.
+	 */
+	WRITE_ONCE(rcu_state.gp_state, RCU_GP_ONOFF);
+	/* Exclude CPU hotplug operations. */
+	rcu_for_each_leaf_node(rnp) {
+		local_irq_save(flags);
+		arch_spin_lock(&rcu_state.ofl_lock);
+		raw_spin_lock_rcu_node(rnp);
+		if (rnp->qsmaskinit == rnp->qsmaskinitnext &&
+		    !rnp->wait_blkd_tasks) {
+			/* Nothing to do on this leaf rcu_node structure. */
+			raw_spin_unlock_rcu_node(rnp);
+			arch_spin_unlock(&rcu_state.ofl_lock);
+			local_irq_restore(flags);
+			continue;
+		}
+
+		/* Record old state, apply changes to ->qsmaskinit field. */
+		oldmask = rnp->qsmaskinit;
+		rnp->qsmaskinit = rnp->qsmaskinitnext;
+
+		/* If zero-ness of ->qsmaskinit changed, propagate up tree. */
+		if (!oldmask != !rnp->qsmaskinit) {
+			if (!oldmask) { /* First online CPU for rcu_node. */
+				if (!rnp->wait_blkd_tasks) /* Ever offline? */
+					rcu_init_new_rnp(rnp);
+			} else if (rcu_preempt_has_tasks(rnp)) {
+				rnp->wait_blkd_tasks = true; /* blocked tasks */
+			} else { /* Last offline CPU and can propagate. */
+				rcu_cleanup_dead_rnp(rnp);
+			}
+		}
+
+		/*
+		 * If all waited-on tasks from prior grace period are
+		 * done, and if all this rcu_node structure's CPUs are
+		 * still offline, propagate up the rcu_node tree and
+		 * clear ->wait_blkd_tasks.  Otherwise, if one of this
+		 * rcu_node structure's CPUs has since come back online,
+		 * simply clear ->wait_blkd_tasks.
+		 */
+		if (rnp->wait_blkd_tasks &&
+		    (!rcu_preempt_has_tasks(rnp) || rnp->qsmaskinit)) {
+			rnp->wait_blkd_tasks = false;
+			if (!rnp->qsmaskinit)
+				rcu_cleanup_dead_rnp(rnp);
+		}
+
+		raw_spin_unlock_rcu_node(rnp);
+		arch_spin_unlock(&rcu_state.ofl_lock);
+		local_irq_restore(flags);
+	}
+	rcu_gp_slow(gp_preinit_delay); /* Races with CPU hotplug. */
+
+	/*
+	 * Set the quiescent-state-needed bits in all the rcu_node
+	 * structures for all currently online CPUs in breadth-first
+	 * order, starting from the root rcu_node structure, relying on the
+	 * layout of the tree within the rcu_state.node[] array.  Note that
+	 * other CPUs will access only the leaves of the hierarchy, thus
+	 * seeing that no grace period is in progress, at least until the
+	 * corresponding leaf node has been initialized.
+	 *
+	 * The grace period cannot complete until the initialization
+	 * process finishes, because this kthread handles both.
+	 */
+	WRITE_ONCE(rcu_state.gp_state, RCU_GP_INIT);
+	rcu_for_each_node_breadth_first(rnp) {
+		rcu_gp_slow(gp_init_delay);
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+		rdp = this_cpu_ptr(&rcu_data);
+		rcu_preempt_check_blocked_tasks(rnp);
+		rnp->qsmask = rnp->qsmaskinit;
+		WRITE_ONCE(rnp->gp_seq, rcu_state.gp_seq);
+		if (rnp == rdp->mynode)
+			(void)__note_gp_changes(rnp, rdp);
+		rcu_preempt_boost_start_gp(rnp);
+		trace_rcu_grace_period_init(rcu_state.name, rnp->gp_seq,
+					    rnp->level, rnp->grplo,
+					    rnp->grphi, rnp->qsmask);
+		/* Quiescent states for tasks on any now-offline CPUs. */
+		mask = rnp->qsmask & ~rnp->qsmaskinitnext;
+		rnp->rcu_gp_init_mask = mask;
+		if ((mask || rnp->wait_blkd_tasks) && rcu_is_leaf_node(rnp))
+			rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
+		else
+			raw_spin_unlock_irq_rcu_node(rnp);
+		cond_resched_tasks_rcu_qs();
+		WRITE_ONCE(rcu_state.gp_activity, jiffies);
+	}
+
+	// If strict, make all CPUs aware of new grace period.
+	if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD))
+		on_each_cpu(rcu_strict_gp_boundary, NULL, 0);
+
+	return true;
+}
+
+/*
+ * Helper function for swait_event_idle_exclusive() wakeup at force-quiescent-state
+ * time.
+ */
+static bool rcu_gp_fqs_check_wake(int *gfp)
+{
+	struct rcu_node *rnp = rcu_get_root();
+
+	// If under overload conditions, force an immediate FQS scan.
+	if (*gfp & RCU_GP_FLAG_OVLD)
+		return true;
+
+	// Someone like call_rcu() requested a force-quiescent-state scan.
+	*gfp = READ_ONCE(rcu_state.gp_flags);
+	if (*gfp & RCU_GP_FLAG_FQS)
+		return true;
+
+	// The current grace period has completed.
+	if (!READ_ONCE(rnp->qsmask) && !rcu_preempt_blocked_readers_cgp(rnp))
+		return true;
+
+	return false;
+}
+
+/*
+ * Do one round of quiescent-state forcing.
+ */
+static void rcu_gp_fqs(bool first_time)
+{
+	int nr_fqs = READ_ONCE(rcu_state.nr_fqs_jiffies_stall);
+	struct rcu_node *rnp = rcu_get_root();
+
+	WRITE_ONCE(rcu_state.gp_activity, jiffies);
+	WRITE_ONCE(rcu_state.n_force_qs, rcu_state.n_force_qs + 1);
+
+	WARN_ON_ONCE(nr_fqs > 3);
+	/* Only countdown nr_fqs for stall purposes if jiffies moves. */
+	if (nr_fqs) {
+		if (nr_fqs == 1) {
+			WRITE_ONCE(rcu_state.jiffies_stall,
+				   jiffies + rcu_jiffies_till_stall_check());
+		}
+		WRITE_ONCE(rcu_state.nr_fqs_jiffies_stall, --nr_fqs);
+	}
+
+	if (first_time) {
+		/* Collect dyntick-idle snapshots. */
+		force_qs_rnp(dyntick_save_progress_counter);
+	} else {
+		/* Handle dyntick-idle and offline CPUs. */
+		force_qs_rnp(rcu_implicit_dynticks_qs);
+	}
+	/* Clear flag to prevent immediate re-entry. */
+	if (READ_ONCE(rcu_state.gp_flags) & RCU_GP_FLAG_FQS) {
+		raw_spin_lock_irq_rcu_node(rnp);
+		WRITE_ONCE(rcu_state.gp_flags,
+			   READ_ONCE(rcu_state.gp_flags) & ~RCU_GP_FLAG_FQS);
+		raw_spin_unlock_irq_rcu_node(rnp);
+	}
+}
+
+/*
+ * Loop doing repeated quiescent-state forcing until the grace period ends.
+ */
+static noinline_for_stack void rcu_gp_fqs_loop(void)
+{
+	bool first_gp_fqs = true;
+	int gf = 0;
+	unsigned long j;
+	int ret;
+	struct rcu_node *rnp = rcu_get_root();
+
+	j = READ_ONCE(jiffies_till_first_fqs);
+	if (rcu_state.cbovld)
+		gf = RCU_GP_FLAG_OVLD;
+	ret = 0;
+	for (;;) {
+		if (rcu_state.cbovld) {
+			j = (j + 2) / 3;
+			if (j <= 0)
+				j = 1;
+		}
+		if (!ret || time_before(jiffies + j, rcu_state.jiffies_force_qs)) {
+			WRITE_ONCE(rcu_state.jiffies_force_qs, jiffies + j);
+			/*
+			 * jiffies_force_qs before RCU_GP_WAIT_FQS state
+			 * update; required for stall checks.
+			 */
+			smp_wmb();
+			WRITE_ONCE(rcu_state.jiffies_kick_kthreads,
+				   jiffies + (j ? 3 * j : 2));
+		}
+		trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq,
+				       TPS("fqswait"));
+		WRITE_ONCE(rcu_state.gp_state, RCU_GP_WAIT_FQS);
+		(void)swait_event_idle_timeout_exclusive(rcu_state.gp_wq,
+				 rcu_gp_fqs_check_wake(&gf), j);
+		rcu_gp_torture_wait();
+		WRITE_ONCE(rcu_state.gp_state, RCU_GP_DOING_FQS);
+		/* Locking provides needed memory barriers. */
+		/*
+		 * Exit the loop if the root rcu_node structure indicates that the grace period
+		 * has ended, leave the loop.  The rcu_preempt_blocked_readers_cgp(rnp) check
+		 * is required only for single-node rcu_node trees because readers blocking
+		 * the current grace period are queued only on leaf rcu_node structures.
+		 * For multi-node trees, checking the root node's ->qsmask suffices, because a
+		 * given root node's ->qsmask bit is cleared only when all CPUs and tasks from
+		 * the corresponding leaf nodes have passed through their quiescent state.
+		 */
+		if (!READ_ONCE(rnp->qsmask) &&
+		    !rcu_preempt_blocked_readers_cgp(rnp))
+			break;
+		/* If time for quiescent-state forcing, do it. */
+		if (!time_after(rcu_state.jiffies_force_qs, jiffies) ||
+		    (gf & (RCU_GP_FLAG_FQS | RCU_GP_FLAG_OVLD))) {
+			trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq,
+					       TPS("fqsstart"));
+			rcu_gp_fqs(first_gp_fqs);
+			gf = 0;
+			if (first_gp_fqs) {
+				first_gp_fqs = false;
+				gf = rcu_state.cbovld ? RCU_GP_FLAG_OVLD : 0;
+			}
+			trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq,
+					       TPS("fqsend"));
+			cond_resched_tasks_rcu_qs();
+			WRITE_ONCE(rcu_state.gp_activity, jiffies);
+			ret = 0; /* Force full wait till next FQS. */
+			j = READ_ONCE(jiffies_till_next_fqs);
+		} else {
+			/* Deal with stray signal. */
+			cond_resched_tasks_rcu_qs();
+			WRITE_ONCE(rcu_state.gp_activity, jiffies);
+			WARN_ON(signal_pending(current));
+			trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq,
+					       TPS("fqswaitsig"));
+			ret = 1; /* Keep old FQS timing. */
+			j = jiffies;
+			if (time_after(jiffies, rcu_state.jiffies_force_qs))
+				j = 1;
+			else
+				j = rcu_state.jiffies_force_qs - j;
+			gf = 0;
+		}
+	}
+}
+
+/*
+ * Clean up after the old grace period.
+ */
+static noinline void rcu_gp_cleanup(void)
+{
+	int cpu;
+	bool needgp = false;
+	unsigned long gp_duration;
+	unsigned long new_gp_seq;
+	bool offloaded;
+	struct rcu_data *rdp;
+	struct rcu_node *rnp = rcu_get_root();
+	struct swait_queue_head *sq;
+
+	WRITE_ONCE(rcu_state.gp_activity, jiffies);
+	raw_spin_lock_irq_rcu_node(rnp);
+	rcu_state.gp_end = jiffies;
+	gp_duration = rcu_state.gp_end - rcu_state.gp_start;
+	if (gp_duration > rcu_state.gp_max)
+		rcu_state.gp_max = gp_duration;
+
+	/*
+	 * We know the grace period is complete, but to everyone else
+	 * it appears to still be ongoing.  But it is also the case
+	 * that to everyone else it looks like there is nothing that
+	 * they can do to advance the grace period.  It is therefore
+	 * safe for us to drop the lock in order to mark the grace
+	 * period as completed in all of the rcu_node structures.
+	 */
+	rcu_poll_gp_seq_end(&rcu_state.gp_seq_polled_snap);
+	raw_spin_unlock_irq_rcu_node(rnp);
+
+	/*
+	 * Propagate new ->gp_seq value to rcu_node structures so that
+	 * other CPUs don't have to wait until the start of the next grace
+	 * period to process their callbacks.  This also avoids some nasty
+	 * RCU grace-period initialization races by forcing the end of
+	 * the current grace period to be completely recorded in all of
+	 * the rcu_node structures before the beginning of the next grace
+	 * period is recorded in any of the rcu_node structures.
+	 */
+	new_gp_seq = rcu_state.gp_seq;
+	rcu_seq_end(&new_gp_seq);
+	rcu_for_each_node_breadth_first(rnp) {
+		raw_spin_lock_irq_rcu_node(rnp);
+		if (WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)))
+			dump_blkd_tasks(rnp, 10);
+		WARN_ON_ONCE(rnp->qsmask);
+		WRITE_ONCE(rnp->gp_seq, new_gp_seq);
+		if (!rnp->parent)
+			smp_mb(); // Order against failing poll_state_synchronize_rcu_full().
+		rdp = this_cpu_ptr(&rcu_data);
+		if (rnp == rdp->mynode)
+			needgp = __note_gp_changes(rnp, rdp) || needgp;
+		/* smp_mb() provided by prior unlock-lock pair. */
+		needgp = rcu_future_gp_cleanup(rnp) || needgp;
+		// Reset overload indication for CPUs no longer overloaded
+		if (rcu_is_leaf_node(rnp))
+			for_each_leaf_node_cpu_mask(rnp, cpu, rnp->cbovldmask) {
+				rdp = per_cpu_ptr(&rcu_data, cpu);
+				check_cb_ovld_locked(rdp, rnp);
+			}
+		sq = rcu_nocb_gp_get(rnp);
+		raw_spin_unlock_irq_rcu_node(rnp);
+		rcu_nocb_gp_cleanup(sq);
+		cond_resched_tasks_rcu_qs();
+		WRITE_ONCE(rcu_state.gp_activity, jiffies);
+		rcu_gp_slow(gp_cleanup_delay);
+	}
+	rnp = rcu_get_root();
+	raw_spin_lock_irq_rcu_node(rnp); /* GP before ->gp_seq update. */
+
+	/* Declare grace period done, trace first to use old GP number. */
+	trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq, TPS("end"));
+	rcu_seq_end(&rcu_state.gp_seq);
+	ASSERT_EXCLUSIVE_WRITER(rcu_state.gp_seq);
+	WRITE_ONCE(rcu_state.gp_state, RCU_GP_IDLE);
+	/* Check for GP requests since above loop. */
+	rdp = this_cpu_ptr(&rcu_data);
+	if (!needgp && ULONG_CMP_LT(rnp->gp_seq, rnp->gp_seq_needed)) {
+		trace_rcu_this_gp(rnp, rdp, rnp->gp_seq_needed,
+				  TPS("CleanupMore"));
+		needgp = true;
+	}
+	/* Advance CBs to reduce false positives below. */
+	offloaded = rcu_rdp_is_offloaded(rdp);
+	if ((offloaded || !rcu_accelerate_cbs(rnp, rdp)) && needgp) {
+
+		// We get here if a grace period was needed (“needgp”)
+		// and the above call to rcu_accelerate_cbs() did not set
+		// the RCU_GP_FLAG_INIT bit in ->gp_state (which records
+		// the need for another grace period).  The purpose
+		// of the “offloaded” check is to avoid invoking
+		// rcu_accelerate_cbs() on an offloaded CPU because we do not
+		// hold the ->nocb_lock needed to safely access an offloaded
+		// ->cblist.  We do not want to acquire that lock because
+		// it can be heavily contended during callback floods.
+
+		WRITE_ONCE(rcu_state.gp_flags, RCU_GP_FLAG_INIT);
+		WRITE_ONCE(rcu_state.gp_req_activity, jiffies);
+		trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq, TPS("newreq"));
+	} else {
+
+		// We get here either if there is no need for an
+		// additional grace period or if rcu_accelerate_cbs() has
+		// already set the RCU_GP_FLAG_INIT bit in ->gp_flags. 
+		// So all we need to do is to clear all of the other
+		// ->gp_flags bits.
+
+		WRITE_ONCE(rcu_state.gp_flags, rcu_state.gp_flags & RCU_GP_FLAG_INIT);
+	}
+	raw_spin_unlock_irq_rcu_node(rnp);
+
+	// If strict, make all CPUs aware of the end of the old grace period.
+	if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD))
+		on_each_cpu(rcu_strict_gp_boundary, NULL, 0);
+}
+
+/*
+ * Body of kthread that handles grace periods.
+ */
+static int __noreturn rcu_gp_kthread(void *unused)
+{
+	rcu_bind_gp_kthread();
+	for (;;) {
+
+		/* Handle grace-period start. */
+		for (;;) {
+			trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq,
+					       TPS("reqwait"));
+			WRITE_ONCE(rcu_state.gp_state, RCU_GP_WAIT_GPS);
+			swait_event_idle_exclusive(rcu_state.gp_wq,
+					 READ_ONCE(rcu_state.gp_flags) &
+					 RCU_GP_FLAG_INIT);
+			rcu_gp_torture_wait();
+			WRITE_ONCE(rcu_state.gp_state, RCU_GP_DONE_GPS);
+			/* Locking provides needed memory barrier. */
+			if (rcu_gp_init())
+				break;
+			cond_resched_tasks_rcu_qs();
+			WRITE_ONCE(rcu_state.gp_activity, jiffies);
+			WARN_ON(signal_pending(current));
+			trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq,
+					       TPS("reqwaitsig"));
+		}
+
+		/* Handle quiescent-state forcing. */
+		rcu_gp_fqs_loop();
+
+		/* Handle grace-period end. */
+		WRITE_ONCE(rcu_state.gp_state, RCU_GP_CLEANUP);
+		rcu_gp_cleanup();
+		WRITE_ONCE(rcu_state.gp_state, RCU_GP_CLEANED);
+	}
+}
+
+/*
+ * Report a full set of quiescent states to the rcu_state data structure.
+ * Invoke rcu_gp_kthread_wake() to awaken the grace-period kthread if
+ * another grace period is required.  Whether we wake the grace-period
+ * kthread or it awakens itself for the next round of quiescent-state
+ * forcing, that kthread will clean up after the just-completed grace
+ * period.  Note that the caller must hold rnp->lock, which is released
+ * before return.
+ */
+static void rcu_report_qs_rsp(unsigned long flags)
+	__releases(rcu_get_root()->lock)
+{
+	raw_lockdep_assert_held_rcu_node(rcu_get_root());
+	WARN_ON_ONCE(!rcu_gp_in_progress());
+	WRITE_ONCE(rcu_state.gp_flags,
+		   READ_ONCE(rcu_state.gp_flags) | RCU_GP_FLAG_FQS);
+	raw_spin_unlock_irqrestore_rcu_node(rcu_get_root(), flags);
+	rcu_gp_kthread_wake();
+}
+
+/*
+ * Similar to rcu_report_qs_rdp(), for which it is a helper function.
+ * Allows quiescent states for a group of CPUs to be reported at one go
+ * to the specified rcu_node structure, though all the CPUs in the group
+ * must be represented by the same rcu_node structure (which need not be a
+ * leaf rcu_node structure, though it often will be).  The gps parameter
+ * is the grace-period snapshot, which means that the quiescent states
+ * are valid only if rnp->gp_seq is equal to gps.  That structure's lock
+ * must be held upon entry, and it is released before return.
+ *
+ * As a special case, if mask is zero, the bit-already-cleared check is
+ * disabled.  This allows propagating quiescent state due to resumed tasks
+ * during grace-period initialization.
+ */
+static void rcu_report_qs_rnp(unsigned long mask, struct rcu_node *rnp,
+			      unsigned long gps, unsigned long flags)
+	__releases(rnp->lock)
+{
+	unsigned long oldmask = 0;
+	struct rcu_node *rnp_c;
+
+	raw_lockdep_assert_held_rcu_node(rnp);
+
+	/* Walk up the rcu_node hierarchy. */
+	for (;;) {
+		if ((!(rnp->qsmask & mask) && mask) || rnp->gp_seq != gps) {
+
+			/*
+			 * Our bit has already been cleared, or the
+			 * relevant grace period is already over, so done.
+			 */
+			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+			return;
+		}
+		WARN_ON_ONCE(oldmask); /* Any child must be all zeroed! */
+		WARN_ON_ONCE(!rcu_is_leaf_node(rnp) &&
+			     rcu_preempt_blocked_readers_cgp(rnp));
+		WRITE_ONCE(rnp->qsmask, rnp->qsmask & ~mask);
+		trace_rcu_quiescent_state_report(rcu_state.name, rnp->gp_seq,
+						 mask, rnp->qsmask, rnp->level,
+						 rnp->grplo, rnp->grphi,
+						 !!rnp->gp_tasks);
+		if (rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) {
+
+			/* Other bits still set at this level, so done. */
+			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+			return;
+		}
+		rnp->completedqs = rnp->gp_seq;
+		mask = rnp->grpmask;
+		if (rnp->parent == NULL) {
+
+			/* No more levels.  Exit loop holding root lock. */
+
+			break;
+		}
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		rnp_c = rnp;
+		rnp = rnp->parent;
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+		oldmask = READ_ONCE(rnp_c->qsmask);
+	}
+
+	/*
+	 * Get here if we are the last CPU to pass through a quiescent
+	 * state for this grace period.  Invoke rcu_report_qs_rsp()
+	 * to clean up and start the next grace period if one is needed.
+	 */
+	rcu_report_qs_rsp(flags); /* releases rnp->lock. */
+}
+
+/*
+ * Record a quiescent state for all tasks that were previously queued
+ * on the specified rcu_node structure and that were blocking the current
+ * RCU grace period.  The caller must hold the corresponding rnp->lock with
+ * irqs disabled, and this lock is released upon return, but irqs remain
+ * disabled.
+ */
+static void __maybe_unused
+rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags)
+	__releases(rnp->lock)
+{
+	unsigned long gps;
+	unsigned long mask;
+	struct rcu_node *rnp_p;
+
+	raw_lockdep_assert_held_rcu_node(rnp);
+	if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT_RCU)) ||
+	    WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)) ||
+	    rnp->qsmask != 0) {
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		return;  /* Still need more quiescent states! */
+	}
+
+	rnp->completedqs = rnp->gp_seq;
+	rnp_p = rnp->parent;
+	if (rnp_p == NULL) {
+		/*
+		 * Only one rcu_node structure in the tree, so don't
+		 * try to report up to its nonexistent parent!
+		 */
+		rcu_report_qs_rsp(flags);
+		return;
+	}
+
+	/* Report up the rest of the hierarchy, tracking current ->gp_seq. */
+	gps = rnp->gp_seq;
+	mask = rnp->grpmask;
+	raw_spin_unlock_rcu_node(rnp);	/* irqs remain disabled. */
+	raw_spin_lock_rcu_node(rnp_p);	/* irqs already disabled. */
+	rcu_report_qs_rnp(mask, rnp_p, gps, flags);
+}
+
+/*
+ * Record a quiescent state for the specified CPU to that CPU's rcu_data
+ * structure.  This must be called from the specified CPU.
+ */
+static void
+rcu_report_qs_rdp(struct rcu_data *rdp)
+{
+	unsigned long flags;
+	unsigned long mask;
+	bool needwake = false;
+	bool needacc = false;
+	struct rcu_node *rnp;
+
+	WARN_ON_ONCE(rdp->cpu != smp_processor_id());
+	rnp = rdp->mynode;
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	if (rdp->cpu_no_qs.b.norm || rdp->gp_seq != rnp->gp_seq ||
+	    rdp->gpwrap) {
+
+		/*
+		 * The grace period in which this quiescent state was
+		 * recorded has ended, so don't report it upwards.
+		 * We will instead need a new quiescent state that lies
+		 * within the current grace period.
+		 */
+		rdp->cpu_no_qs.b.norm = true;	/* need qs for new gp. */
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		return;
+	}
+	mask = rdp->grpmask;
+	rdp->core_needs_qs = false;
+	if ((rnp->qsmask & mask) == 0) {
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	} else {
+		/*
+		 * This GP can't end until cpu checks in, so all of our
+		 * callbacks can be processed during the next GP.
+		 *
+		 * NOCB kthreads have their own way to deal with that...
+		 */
+		if (!rcu_rdp_is_offloaded(rdp)) {
+			needwake = rcu_accelerate_cbs(rnp, rdp);
+		} else if (!rcu_segcblist_completely_offloaded(&rdp->cblist)) {
+			/*
+			 * ...but NOCB kthreads may miss or delay callbacks acceleration
+			 * if in the middle of a (de-)offloading process.
+			 */
+			needacc = true;
+		}
+
+		rcu_disable_urgency_upon_qs(rdp);
+		rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
+		/* ^^^ Released rnp->lock */
+		if (needwake)
+			rcu_gp_kthread_wake();
+
+		if (needacc) {
+			rcu_nocb_lock_irqsave(rdp, flags);
+			rcu_accelerate_cbs_unlocked(rnp, rdp);
+			rcu_nocb_unlock_irqrestore(rdp, flags);
+		}
+	}
+}
+
+/*
+ * Check to see if there is a new grace period of which this CPU
+ * is not yet aware, and if so, set up local rcu_data state for it.
+ * Otherwise, see if this CPU has just passed through its first
+ * quiescent state for this grace period, and record that fact if so.
+ */
+static void
+rcu_check_quiescent_state(struct rcu_data *rdp)
+{
+	/* Check for grace-period ends and beginnings. */
+	note_gp_changes(rdp);
+
+	/*
+	 * Does this CPU still need to do its part for current grace period?
+	 * If no, return and let the other CPUs do their part as well.
+	 */
+	if (!rdp->core_needs_qs)
+		return;
+
+	/*
+	 * Was there a quiescent state since the beginning of the grace
+	 * period? If no, then exit and wait for the next call.
+	 */
+	if (rdp->cpu_no_qs.b.norm)
+		return;
+
+	/*
+	 * Tell RCU we are done (but rcu_report_qs_rdp() will be the
+	 * judge of that).
+	 */
+	rcu_report_qs_rdp(rdp);
+}
+
+/*
+ * Near the end of the offline process.  Trace the fact that this CPU
+ * is going offline.
+ */
+int rcutree_dying_cpu(unsigned int cpu)
+{
+	bool blkd;
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+	struct rcu_node *rnp = rdp->mynode;
+
+	if (!IS_ENABLED(CONFIG_HOTPLUG_CPU))
+		return 0;
+
+	blkd = !!(rnp->qsmask & rdp->grpmask);
+	trace_rcu_grace_period(rcu_state.name, READ_ONCE(rnp->gp_seq),
+			       blkd ? TPS("cpuofl-bgp") : TPS("cpuofl"));
+	return 0;
+}
+
+/*
+ * All CPUs for the specified rcu_node structure have gone offline,
+ * and all tasks that were preempted within an RCU read-side critical
+ * section while running on one of those CPUs have since exited their RCU
+ * read-side critical section.  Some other CPU is reporting this fact with
+ * the specified rcu_node structure's ->lock held and interrupts disabled.
+ * This function therefore goes up the tree of rcu_node structures,
+ * clearing the corresponding bits in the ->qsmaskinit fields.  Note that
+ * the leaf rcu_node structure's ->qsmaskinit field has already been
+ * updated.
+ *
+ * This function does check that the specified rcu_node structure has
+ * all CPUs offline and no blocked tasks, so it is OK to invoke it
+ * prematurely.  That said, invoking it after the fact will cost you
+ * a needless lock acquisition.  So once it has done its work, don't
+ * invoke it again.
+ */
+static void rcu_cleanup_dead_rnp(struct rcu_node *rnp_leaf)
+{
+	long mask;
+	struct rcu_node *rnp = rnp_leaf;
+
+	raw_lockdep_assert_held_rcu_node(rnp_leaf);
+	if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) ||
+	    WARN_ON_ONCE(rnp_leaf->qsmaskinit) ||
+	    WARN_ON_ONCE(rcu_preempt_has_tasks(rnp_leaf)))
+		return;
+	for (;;) {
+		mask = rnp->grpmask;
+		rnp = rnp->parent;
+		if (!rnp)
+			break;
+		raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
+		rnp->qsmaskinit &= ~mask;
+		/* Between grace periods, so better already be zero! */
+		WARN_ON_ONCE(rnp->qsmask);
+		if (rnp->qsmaskinit) {
+			raw_spin_unlock_rcu_node(rnp);
+			/* irqs remain disabled. */
+			return;
+		}
+		raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */
+	}
+}
+
+/*
+ * The CPU has been completely removed, and some other CPU is reporting
+ * this fact from process context.  Do the remainder of the cleanup.
+ * There can only be one CPU hotplug operation at a time, so no need for
+ * explicit locking.
+ */
+int rcutree_dead_cpu(unsigned int cpu)
+{
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+	struct rcu_node *rnp = rdp->mynode;  /* Outgoing CPU's rdp & rnp. */
+
+	if (!IS_ENABLED(CONFIG_HOTPLUG_CPU))
+		return 0;
+
+	WRITE_ONCE(rcu_state.n_online_cpus, rcu_state.n_online_cpus - 1);
+	/* Adjust any no-longer-needed kthreads. */
+	rcu_boost_kthread_setaffinity(rnp, -1);
+	// Stop-machine done, so allow nohz_full to disable tick.
+	tick_dep_clear(TICK_DEP_BIT_RCU);
+	return 0;
+}
+
+/*
+ * Invoke any RCU callbacks that have made it to the end of their grace
+ * period.  Throttle as specified by rdp->blimit.
+ */
+static void rcu_do_batch(struct rcu_data *rdp)
+{
+	int div;
+	bool __maybe_unused empty;
+	unsigned long flags;
+	struct rcu_head *rhp;
+	struct rcu_cblist rcl = RCU_CBLIST_INITIALIZER(rcl);
+	long bl, count = 0;
+	long pending, tlimit = 0;
+
+	/* If no callbacks are ready, just return. */
+	if (!rcu_segcblist_ready_cbs(&rdp->cblist)) {
+		trace_rcu_batch_start(rcu_state.name,
+				      rcu_segcblist_n_cbs(&rdp->cblist), 0);
+		trace_rcu_batch_end(rcu_state.name, 0,
+				    !rcu_segcblist_empty(&rdp->cblist),
+				    need_resched(), is_idle_task(current),
+				    rcu_is_callbacks_kthread(rdp));
+		return;
+	}
+
+	/*
+	 * Extract the list of ready callbacks, disabling IRQs to prevent
+	 * races with call_rcu() from interrupt handlers.  Leave the
+	 * callback counts, as rcu_barrier() needs to be conservative.
+	 */
+	rcu_nocb_lock_irqsave(rdp, flags);
+	WARN_ON_ONCE(cpu_is_offline(smp_processor_id()));
+	pending = rcu_segcblist_n_cbs(&rdp->cblist);
+	div = READ_ONCE(rcu_divisor);
+	div = div < 0 ? 7 : div > sizeof(long) * 8 - 2 ? sizeof(long) * 8 - 2 : div;
+	bl = max(rdp->blimit, pending >> div);
+	if (in_serving_softirq() && unlikely(bl > 100)) {
+		long rrn = READ_ONCE(rcu_resched_ns);
+
+		rrn = rrn < NSEC_PER_MSEC ? NSEC_PER_MSEC : rrn > NSEC_PER_SEC ? NSEC_PER_SEC : rrn;
+		tlimit = local_clock() + rrn;
+	}
+	trace_rcu_batch_start(rcu_state.name,
+			      rcu_segcblist_n_cbs(&rdp->cblist), bl);
+	rcu_segcblist_extract_done_cbs(&rdp->cblist, &rcl);
+	if (rcu_rdp_is_offloaded(rdp))
+		rdp->qlen_last_fqs_check = rcu_segcblist_n_cbs(&rdp->cblist);
+
+	trace_rcu_segcb_stats(&rdp->cblist, TPS("SegCbDequeued"));
+	rcu_nocb_unlock_irqrestore(rdp, flags);
+
+	/* Invoke callbacks. */
+	tick_dep_set_task(current, TICK_DEP_BIT_RCU);
+	rhp = rcu_cblist_dequeue(&rcl);
+
+	for (; rhp; rhp = rcu_cblist_dequeue(&rcl)) {
+		rcu_callback_t f;
+
+		count++;
+		debug_rcu_head_unqueue(rhp);
+
+		rcu_lock_acquire(&rcu_callback_map);
+		trace_rcu_invoke_callback(rcu_state.name, rhp);
+
+		f = rhp->func;
+		WRITE_ONCE(rhp->func, (rcu_callback_t)0L);
+		f(rhp);
+
+		rcu_lock_release(&rcu_callback_map);
+
+		/*
+		 * Stop only if limit reached and CPU has something to do.
+		 */
+		if (in_serving_softirq()) {
+			if (count >= bl && (need_resched() || !is_idle_task(current)))
+				break;
+			/*
+			 * Make sure we don't spend too much time here and deprive other
+			 * softirq vectors of CPU cycles.
+			 */
+			if (unlikely(tlimit)) {
+				/* only call local_clock() every 32 callbacks */
+				if (likely((count & 31) || local_clock() < tlimit))
+					continue;
+				/* Exceeded the time limit, so leave. */
+				break;
+			}
+		} else {
+			local_bh_enable();
+			lockdep_assert_irqs_enabled();
+			cond_resched_tasks_rcu_qs();
+			lockdep_assert_irqs_enabled();
+			local_bh_disable();
+		}
+	}
+
+	rcu_nocb_lock_irqsave(rdp, flags);
+	rdp->n_cbs_invoked += count;
+	trace_rcu_batch_end(rcu_state.name, count, !!rcl.head, need_resched(),
+			    is_idle_task(current), rcu_is_callbacks_kthread(rdp));
+
+	/* Update counts and requeue any remaining callbacks. */
+	rcu_segcblist_insert_done_cbs(&rdp->cblist, &rcl);
+	rcu_segcblist_add_len(&rdp->cblist, -count);
+
+	/* Reinstate batch limit if we have worked down the excess. */
+	count = rcu_segcblist_n_cbs(&rdp->cblist);
+	if (rdp->blimit >= DEFAULT_MAX_RCU_BLIMIT && count <= qlowmark)
+		rdp->blimit = blimit;
+
+	/* Reset ->qlen_last_fqs_check trigger if enough CBs have drained. */
+	if (count == 0 && rdp->qlen_last_fqs_check != 0) {
+		rdp->qlen_last_fqs_check = 0;
+		rdp->n_force_qs_snap = READ_ONCE(rcu_state.n_force_qs);
+	} else if (count < rdp->qlen_last_fqs_check - qhimark)
+		rdp->qlen_last_fqs_check = count;
+
+	/*
+	 * The following usually indicates a double call_rcu().  To track
+	 * this down, try building with CONFIG_DEBUG_OBJECTS_RCU_HEAD=y.
+	 */
+	empty = rcu_segcblist_empty(&rdp->cblist);
+	WARN_ON_ONCE(count == 0 && !empty);
+	WARN_ON_ONCE(!IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
+		     count != 0 && empty);
+	WARN_ON_ONCE(count == 0 && rcu_segcblist_n_segment_cbs(&rdp->cblist) != 0);
+	WARN_ON_ONCE(!empty && rcu_segcblist_n_segment_cbs(&rdp->cblist) == 0);
+
+	rcu_nocb_unlock_irqrestore(rdp, flags);
+
+	tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
+}
+
+/*
+ * This function is invoked from each scheduling-clock interrupt,
+ * and checks to see if this CPU is in a non-context-switch quiescent
+ * state, for example, user mode or idle loop.  It also schedules RCU
+ * core processing.  If the current grace period has gone on too long,
+ * it will ask the scheduler to manufacture a context switch for the sole
+ * purpose of providing the needed quiescent state.
+ */
+void rcu_sched_clock_irq(int user)
+{
+	unsigned long j;
+
+	if (IS_ENABLED(CONFIG_PROVE_RCU)) {
+		j = jiffies;
+		WARN_ON_ONCE(time_before(j, __this_cpu_read(rcu_data.last_sched_clock)));
+		__this_cpu_write(rcu_data.last_sched_clock, j);
+	}
+	trace_rcu_utilization(TPS("Start scheduler-tick"));
+	lockdep_assert_irqs_disabled();
+	raw_cpu_inc(rcu_data.ticks_this_gp);
+	/* The load-acquire pairs with the store-release setting to true. */
+	if (smp_load_acquire(this_cpu_ptr(&rcu_data.rcu_urgent_qs))) {
+		/* Idle and userspace execution already are quiescent states. */
+		if (!rcu_is_cpu_rrupt_from_idle() && !user) {
+			set_tsk_need_resched(current);
+			set_preempt_need_resched();
+		}
+		__this_cpu_write(rcu_data.rcu_urgent_qs, false);
+	}
+	rcu_flavor_sched_clock_irq(user);
+	if (rcu_pending(user))
+		invoke_rcu_core();
+	if (user || rcu_is_cpu_rrupt_from_idle())
+		rcu_note_voluntary_context_switch(current);
+	lockdep_assert_irqs_disabled();
+
+	trace_rcu_utilization(TPS("End scheduler-tick"));
+}
+
+/*
+ * Scan the leaf rcu_node structures.  For each structure on which all
+ * CPUs have reported a quiescent state and on which there are tasks
+ * blocking the current grace period, initiate RCU priority boosting.
+ * Otherwise, invoke the specified function to check dyntick state for
+ * each CPU that has not yet reported a quiescent state.
+ */
+static void force_qs_rnp(int (*f)(struct rcu_data *rdp))
+{
+	int cpu;
+	unsigned long flags;
+	unsigned long mask;
+	struct rcu_data *rdp;
+	struct rcu_node *rnp;
+
+	rcu_state.cbovld = rcu_state.cbovldnext;
+	rcu_state.cbovldnext = false;
+	rcu_for_each_leaf_node(rnp) {
+		cond_resched_tasks_rcu_qs();
+		mask = 0;
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+		rcu_state.cbovldnext |= !!rnp->cbovldmask;
+		if (rnp->qsmask == 0) {
+			if (rcu_preempt_blocked_readers_cgp(rnp)) {
+				/*
+				 * No point in scanning bits because they
+				 * are all zero.  But we might need to
+				 * priority-boost blocked readers.
+				 */
+				rcu_initiate_boost(rnp, flags);
+				/* rcu_initiate_boost() releases rnp->lock */
+				continue;
+			}
+			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+			continue;
+		}
+		for_each_leaf_node_cpu_mask(rnp, cpu, rnp->qsmask) {
+			rdp = per_cpu_ptr(&rcu_data, cpu);
+			if (f(rdp)) {
+				mask |= rdp->grpmask;
+				rcu_disable_urgency_upon_qs(rdp);
+			}
+		}
+		if (mask != 0) {
+			/* Idle/offline CPUs, report (releases rnp->lock). */
+			rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
+		} else {
+			/* Nothing to do here, so just drop the lock. */
+			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		}
+	}
+}
+
+/*
+ * Force quiescent states on reluctant CPUs, and also detect which
+ * CPUs are in dyntick-idle mode.
+ */
+void rcu_force_quiescent_state(void)
+{
+	unsigned long flags;
+	bool ret;
+	struct rcu_node *rnp;
+	struct rcu_node *rnp_old = NULL;
+
+	/* Funnel through hierarchy to reduce memory contention. */
+	rnp = raw_cpu_read(rcu_data.mynode);
+	for (; rnp != NULL; rnp = rnp->parent) {
+		ret = (READ_ONCE(rcu_state.gp_flags) & RCU_GP_FLAG_FQS) ||
+		       !raw_spin_trylock(&rnp->fqslock);
+		if (rnp_old != NULL)
+			raw_spin_unlock(&rnp_old->fqslock);
+		if (ret)
+			return;
+		rnp_old = rnp;
+	}
+	/* rnp_old == rcu_get_root(), rnp == NULL. */
+
+	/* Reached the root of the rcu_node tree, acquire lock. */
+	raw_spin_lock_irqsave_rcu_node(rnp_old, flags);
+	raw_spin_unlock(&rnp_old->fqslock);
+	if (READ_ONCE(rcu_state.gp_flags) & RCU_GP_FLAG_FQS) {
+		raw_spin_unlock_irqrestore_rcu_node(rnp_old, flags);
+		return;  /* Someone beat us to it. */
+	}
+	WRITE_ONCE(rcu_state.gp_flags,
+		   READ_ONCE(rcu_state.gp_flags) | RCU_GP_FLAG_FQS);
+	raw_spin_unlock_irqrestore_rcu_node(rnp_old, flags);
+	rcu_gp_kthread_wake();
+}
+EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);
+
+// Workqueue handler for an RCU reader for kernels enforcing struct RCU
+// grace periods.
+static void strict_work_handler(struct work_struct *work)
+{
+	rcu_read_lock();
+	rcu_read_unlock();
+}
+
+/* Perform RCU core processing work for the current CPU.  */
+static __latent_entropy void rcu_core(void)
+{
+	unsigned long flags;
+	struct rcu_data *rdp = raw_cpu_ptr(&rcu_data);
+	struct rcu_node *rnp = rdp->mynode;
+	/*
+	 * On RT rcu_core() can be preempted when IRQs aren't disabled.
+	 * Therefore this function can race with concurrent NOCB (de-)offloading
+	 * on this CPU and the below condition must be considered volatile.
+	 * However if we race with:
+	 *
+	 * _ Offloading:   In the worst case we accelerate or process callbacks
+	 *                 concurrently with NOCB kthreads. We are guaranteed to
+	 *                 call rcu_nocb_lock() if that happens.
+	 *
+	 * _ Deoffloading: In the worst case we miss callbacks acceleration or
+	 *                 processing. This is fine because the early stage
+	 *                 of deoffloading invokes rcu_core() after setting
+	 *                 SEGCBLIST_RCU_CORE. So we guarantee that we'll process
+	 *                 what could have been dismissed without the need to wait
+	 *                 for the next rcu_pending() check in the next jiffy.
+	 */
+	const bool do_batch = !rcu_segcblist_completely_offloaded(&rdp->cblist);
+
+	if (cpu_is_offline(smp_processor_id()))
+		return;
+	trace_rcu_utilization(TPS("Start RCU core"));
+	WARN_ON_ONCE(!rdp->beenonline);
+
+	/* Report any deferred quiescent states if preemption enabled. */
+	if (IS_ENABLED(CONFIG_PREEMPT_COUNT) && (!(preempt_count() & PREEMPT_MASK))) {
+		rcu_preempt_deferred_qs(current);
+	} else if (rcu_preempt_need_deferred_qs(current)) {
+		set_tsk_need_resched(current);
+		set_preempt_need_resched();
+	}
+
+	/* Update RCU state based on any recent quiescent states. */
+	rcu_check_quiescent_state(rdp);
+
+	/* No grace period and unregistered callbacks? */
+	if (!rcu_gp_in_progress() &&
+	    rcu_segcblist_is_enabled(&rdp->cblist) && do_batch) {
+		rcu_nocb_lock_irqsave(rdp, flags);
+		if (!rcu_segcblist_restempty(&rdp->cblist, RCU_NEXT_READY_TAIL))
+			rcu_accelerate_cbs_unlocked(rnp, rdp);
+		rcu_nocb_unlock_irqrestore(rdp, flags);
+	}
+
+	rcu_check_gp_start_stall(rnp, rdp, rcu_jiffies_till_stall_check());
+
+	/* If there are callbacks ready, invoke them. */
+	if (do_batch && rcu_segcblist_ready_cbs(&rdp->cblist) &&
+	    likely(READ_ONCE(rcu_scheduler_fully_active))) {
+		rcu_do_batch(rdp);
+		/* Re-invoke RCU core processing if there are callbacks remaining. */
+		if (rcu_segcblist_ready_cbs(&rdp->cblist))
+			invoke_rcu_core();
+	}
+
+	/* Do any needed deferred wakeups of rcuo kthreads. */
+	do_nocb_deferred_wakeup(rdp);
+	trace_rcu_utilization(TPS("End RCU core"));
+
+	// If strict GPs, schedule an RCU reader in a clean environment.
+	if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD))
+		queue_work_on(rdp->cpu, rcu_gp_wq, &rdp->strict_work);
+}
+
+static void rcu_core_si(struct softirq_action *h)
+{
+	rcu_core();
+}
+
+static void rcu_wake_cond(struct task_struct *t, int status)
+{
+	/*
+	 * If the thread is yielding, only wake it when this
+	 * is invoked from idle
+	 */
+	if (t && (status != RCU_KTHREAD_YIELDING || is_idle_task(current)))
+		wake_up_process(t);
+}
+
+static void invoke_rcu_core_kthread(void)
+{
+	struct task_struct *t;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__this_cpu_write(rcu_data.rcu_cpu_has_work, 1);
+	t = __this_cpu_read(rcu_data.rcu_cpu_kthread_task);
+	if (t != NULL && t != current)
+		rcu_wake_cond(t, __this_cpu_read(rcu_data.rcu_cpu_kthread_status));
+	local_irq_restore(flags);
+}
+
+/*
+ * Wake up this CPU's rcuc kthread to do RCU core processing.
+ */
+static void invoke_rcu_core(void)
+{
+	if (!cpu_online(smp_processor_id()))
+		return;
+	if (use_softirq)
+		raise_softirq(RCU_SOFTIRQ);
+	else
+		invoke_rcu_core_kthread();
+}
+
+static void rcu_cpu_kthread_park(unsigned int cpu)
+{
+	per_cpu(rcu_data.rcu_cpu_kthread_status, cpu) = RCU_KTHREAD_OFFCPU;
+}
+
+static int rcu_cpu_kthread_should_run(unsigned int cpu)
+{
+	return __this_cpu_read(rcu_data.rcu_cpu_has_work);
+}
+
+/*
+ * Per-CPU kernel thread that invokes RCU callbacks.  This replaces
+ * the RCU softirq used in configurations of RCU that do not support RCU
+ * priority boosting.
+ */
+static void rcu_cpu_kthread(unsigned int cpu)
+{
+	unsigned int *statusp = this_cpu_ptr(&rcu_data.rcu_cpu_kthread_status);
+	char work, *workp = this_cpu_ptr(&rcu_data.rcu_cpu_has_work);
+	unsigned long *j = this_cpu_ptr(&rcu_data.rcuc_activity);
+	int spincnt;
+
+	trace_rcu_utilization(TPS("Start CPU kthread@rcu_run"));
+	for (spincnt = 0; spincnt < 10; spincnt++) {
+		WRITE_ONCE(*j, jiffies);
+		local_bh_disable();
+		*statusp = RCU_KTHREAD_RUNNING;
+		local_irq_disable();
+		work = *workp;
+		*workp = 0;
+		local_irq_enable();
+		if (work)
+			rcu_core();
+		local_bh_enable();
+		if (*workp == 0) {
+			trace_rcu_utilization(TPS("End CPU kthread@rcu_wait"));
+			*statusp = RCU_KTHREAD_WAITING;
+			return;
+		}
+	}
+	*statusp = RCU_KTHREAD_YIELDING;
+	trace_rcu_utilization(TPS("Start CPU kthread@rcu_yield"));
+	schedule_timeout_idle(2);
+	trace_rcu_utilization(TPS("End CPU kthread@rcu_yield"));
+	*statusp = RCU_KTHREAD_WAITING;
+	WRITE_ONCE(*j, jiffies);
+}
+
+static struct smp_hotplug_thread rcu_cpu_thread_spec = {
+	.store			= &rcu_data.rcu_cpu_kthread_task,
+	.thread_should_run	= rcu_cpu_kthread_should_run,
+	.thread_fn		= rcu_cpu_kthread,
+	.thread_comm		= "rcuc/%u",
+	.setup			= rcu_cpu_kthread_setup,
+	.park			= rcu_cpu_kthread_park,
+};
+
+/*
+ * Spawn per-CPU RCU core processing kthreads.
+ */
+static int __init rcu_spawn_core_kthreads(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		per_cpu(rcu_data.rcu_cpu_has_work, cpu) = 0;
+	if (use_softirq)
+		return 0;
+	WARN_ONCE(smpboot_register_percpu_thread(&rcu_cpu_thread_spec),
+		  "%s: Could not start rcuc kthread, OOM is now expected behavior\n", __func__);
+	return 0;
+}
+
+/*
+ * Handle any core-RCU processing required by a call_rcu() invocation.
+ */
+static void __call_rcu_core(struct rcu_data *rdp, struct rcu_head *head,
+			    unsigned long flags)
+{
+	/*
+	 * If called from an extended quiescent state, invoke the RCU
+	 * core in order to force a re-evaluation of RCU's idleness.
+	 */
+	if (!rcu_is_watching())
+		invoke_rcu_core();
+
+	/* If interrupts were disabled or CPU offline, don't invoke RCU core. */
+	if (irqs_disabled_flags(flags) || cpu_is_offline(smp_processor_id()))
+		return;
+
+	/*
+	 * Force the grace period if too many callbacks or too long waiting.
+	 * Enforce hysteresis, and don't invoke rcu_force_quiescent_state()
+	 * if some other CPU has recently done so.  Also, don't bother
+	 * invoking rcu_force_quiescent_state() if the newly enqueued callback
+	 * is the only one waiting for a grace period to complete.
+	 */
+	if (unlikely(rcu_segcblist_n_cbs(&rdp->cblist) >
+		     rdp->qlen_last_fqs_check + qhimark)) {
+
+		/* Are we ignoring a completed grace period? */
+		note_gp_changes(rdp);
+
+		/* Start a new grace period if one not already started. */
+		if (!rcu_gp_in_progress()) {
+			rcu_accelerate_cbs_unlocked(rdp->mynode, rdp);
+		} else {
+			/* Give the grace period a kick. */
+			rdp->blimit = DEFAULT_MAX_RCU_BLIMIT;
+			if (READ_ONCE(rcu_state.n_force_qs) == rdp->n_force_qs_snap &&
+			    rcu_segcblist_first_pend_cb(&rdp->cblist) != head)
+				rcu_force_quiescent_state();
+			rdp->n_force_qs_snap = READ_ONCE(rcu_state.n_force_qs);
+			rdp->qlen_last_fqs_check = rcu_segcblist_n_cbs(&rdp->cblist);
+		}
+	}
+}
+
+/*
+ * RCU callback function to leak a callback.
+ */
+static void rcu_leak_callback(struct rcu_head *rhp)
+{
+}
+
+/*
+ * Check and if necessary update the leaf rcu_node structure's
+ * ->cbovldmask bit corresponding to the current CPU based on that CPU's
+ * number of queued RCU callbacks.  The caller must hold the leaf rcu_node
+ * structure's ->lock.
+ */
+static void check_cb_ovld_locked(struct rcu_data *rdp, struct rcu_node *rnp)
+{
+	raw_lockdep_assert_held_rcu_node(rnp);
+	if (qovld_calc <= 0)
+		return; // Early boot and wildcard value set.
+	if (rcu_segcblist_n_cbs(&rdp->cblist) >= qovld_calc)
+		WRITE_ONCE(rnp->cbovldmask, rnp->cbovldmask | rdp->grpmask);
+	else
+		WRITE_ONCE(rnp->cbovldmask, rnp->cbovldmask & ~rdp->grpmask);
+}
+
+/*
+ * Check and if necessary update the leaf rcu_node structure's
+ * ->cbovldmask bit corresponding to the current CPU based on that CPU's
+ * number of queued RCU callbacks.  No locks need be held, but the
+ * caller must have disabled interrupts.
+ *
+ * Note that this function ignores the possibility that there are a lot
+ * of callbacks all of which have already seen the end of their respective
+ * grace periods.  This omission is due to the need for no-CBs CPUs to
+ * be holding ->nocb_lock to do this check, which is too heavy for a
+ * common-case operation.
+ */
+static void check_cb_ovld(struct rcu_data *rdp)
+{
+	struct rcu_node *const rnp = rdp->mynode;
+
+	if (qovld_calc <= 0 ||
+	    ((rcu_segcblist_n_cbs(&rdp->cblist) >= qovld_calc) ==
+	     !!(READ_ONCE(rnp->cbovldmask) & rdp->grpmask)))
+		return; // Early boot wildcard value or already set correctly.
+	raw_spin_lock_rcu_node(rnp);
+	check_cb_ovld_locked(rdp, rnp);
+	raw_spin_unlock_rcu_node(rnp);
+}
+
+/**
+ * call_rcu() - Queue an RCU callback for invocation after a grace period.
+ * @head: structure to be used for queueing the RCU updates.
+ * @func: actual callback function to be invoked after the grace period
+ *
+ * The callback function will be invoked some time after a full grace
+ * period elapses, in other words after all pre-existing RCU read-side
+ * critical sections have completed.  However, the callback function
+ * might well execute concurrently with RCU read-side critical sections
+ * that started after call_rcu() was invoked.
+ *
+ * RCU read-side critical sections are delimited by rcu_read_lock()
+ * and rcu_read_unlock(), and may be nested.  In addition, but only in
+ * v5.0 and later, regions of code across which interrupts, preemption,
+ * or softirqs have been disabled also serve as RCU read-side critical
+ * sections.  This includes hardware interrupt handlers, softirq handlers,
+ * and NMI handlers.
+ *
+ * Note that all CPUs must agree that the grace period extended beyond
+ * all pre-existing RCU read-side critical section.  On systems with more
+ * than one CPU, this means that when "func()" is invoked, each CPU is
+ * guaranteed to have executed a full memory barrier since the end of its
+ * last RCU read-side critical section whose beginning preceded the call
+ * to call_rcu().  It also means that each CPU executing an RCU read-side
+ * critical section that continues beyond the start of "func()" must have
+ * executed a memory barrier after the call_rcu() but before the beginning
+ * of that RCU read-side critical section.  Note that these guarantees
+ * include CPUs that are offline, idle, or executing in user mode, as
+ * well as CPUs that are executing in the kernel.
+ *
+ * Furthermore, if CPU A invoked call_rcu() and CPU B invoked the
+ * resulting RCU callback function "func()", then both CPU A and CPU B are
+ * guaranteed to execute a full memory barrier during the time interval
+ * between the call to call_rcu() and the invocation of "func()" -- even
+ * if CPU A and CPU B are the same CPU (but again only if the system has
+ * more than one CPU).
+ *
+ * Implementation of these memory-ordering guarantees is described here:
+ * Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst.
+ */
+void call_rcu(struct rcu_head *head, rcu_callback_t func)
+{
+	static atomic_t doublefrees;
+	unsigned long flags;
+	struct rcu_data *rdp;
+	bool was_alldone;
+
+	/* Misaligned rcu_head! */
+	WARN_ON_ONCE((unsigned long)head & (sizeof(void *) - 1));
+
+	if (debug_rcu_head_queue(head)) {
+		/*
+		 * Probable double call_rcu(), so leak the callback.
+		 * Use rcu:rcu_callback trace event to find the previous
+		 * time callback was passed to call_rcu().
+		 */
+		if (atomic_inc_return(&doublefrees) < 4) {
+			pr_err("%s(): Double-freed CB %p->%pS()!!!  ", __func__, head, head->func);
+			mem_dump_obj(head);
+		}
+		WRITE_ONCE(head->func, rcu_leak_callback);
+		return;
+	}
+	head->func = func;
+	head->next = NULL;
+	kasan_record_aux_stack_noalloc(head);
+	local_irq_save(flags);
+	rdp = this_cpu_ptr(&rcu_data);
+
+	/* Add the callback to our list. */
+	if (unlikely(!rcu_segcblist_is_enabled(&rdp->cblist))) {
+		// This can trigger due to call_rcu() from offline CPU:
+		WARN_ON_ONCE(rcu_scheduler_active != RCU_SCHEDULER_INACTIVE);
+		WARN_ON_ONCE(!rcu_is_watching());
+		// Very early boot, before rcu_init().  Initialize if needed
+		// and then drop through to queue the callback.
+		if (rcu_segcblist_empty(&rdp->cblist))
+			rcu_segcblist_init(&rdp->cblist);
+	}
+
+	check_cb_ovld(rdp);
+	if (rcu_nocb_try_bypass(rdp, head, &was_alldone, flags))
+		return; // Enqueued onto ->nocb_bypass, so just leave.
+	// If no-CBs CPU gets here, rcu_nocb_try_bypass() acquired ->nocb_lock.
+	rcu_segcblist_enqueue(&rdp->cblist, head);
+	if (__is_kvfree_rcu_offset((unsigned long)func))
+		trace_rcu_kvfree_callback(rcu_state.name, head,
+					 (unsigned long)func,
+					 rcu_segcblist_n_cbs(&rdp->cblist));
+	else
+		trace_rcu_callback(rcu_state.name, head,
+				   rcu_segcblist_n_cbs(&rdp->cblist));
+
+	trace_rcu_segcb_stats(&rdp->cblist, TPS("SegCBQueued"));
+
+	/* Go handle any RCU core processing required. */
+	if (unlikely(rcu_rdp_is_offloaded(rdp))) {
+		__call_rcu_nocb_wake(rdp, was_alldone, flags); /* unlocks */
+	} else {
+		__call_rcu_core(rdp, head, flags);
+		local_irq_restore(flags);
+	}
+}
+EXPORT_SYMBOL_GPL(call_rcu);
+
+
+/* Maximum number of jiffies to wait before draining a batch. */
+#define KFREE_DRAIN_JIFFIES (5 * HZ)
+#define KFREE_N_BATCHES 2
+#define FREE_N_CHANNELS 2
+
+/**
+ * struct kvfree_rcu_bulk_data - single block to store kvfree_rcu() pointers
+ * @nr_records: Number of active pointers in the array
+ * @next: Next bulk object in the block chain
+ * @records: Array of the kvfree_rcu() pointers
+ */
+struct kvfree_rcu_bulk_data {
+	unsigned long nr_records;
+	struct kvfree_rcu_bulk_data *next;
+	void *records[];
+};
+
+/*
+ * This macro defines how many entries the "records" array
+ * will contain. It is based on the fact that the size of
+ * kvfree_rcu_bulk_data structure becomes exactly one page.
+ */
+#define KVFREE_BULK_MAX_ENTR \
+	((PAGE_SIZE - sizeof(struct kvfree_rcu_bulk_data)) / sizeof(void *))
+
+/**
+ * struct kfree_rcu_cpu_work - single batch of kfree_rcu() requests
+ * @rcu_work: Let queue_rcu_work() invoke workqueue handler after grace period
+ * @head_free: List of kfree_rcu() objects waiting for a grace period
+ * @bkvhead_free: Bulk-List of kvfree_rcu() objects waiting for a grace period
+ * @krcp: Pointer to @kfree_rcu_cpu structure
+ */
+
+struct kfree_rcu_cpu_work {
+	struct rcu_work rcu_work;
+	struct rcu_head *head_free;
+	struct kvfree_rcu_bulk_data *bkvhead_free[FREE_N_CHANNELS];
+	struct kfree_rcu_cpu *krcp;
+};
+
+/**
+ * struct kfree_rcu_cpu - batch up kfree_rcu() requests for RCU grace period
+ * @head: List of kfree_rcu() objects not yet waiting for a grace period
+ * @bkvhead: Bulk-List of kvfree_rcu() objects not yet waiting for a grace period
+ * @krw_arr: Array of batches of kfree_rcu() objects waiting for a grace period
+ * @lock: Synchronize access to this structure
+ * @monitor_work: Promote @head to @head_free after KFREE_DRAIN_JIFFIES
+ * @initialized: The @rcu_work fields have been initialized
+ * @count: Number of objects for which GP not started
+ * @bkvcache:
+ *	A simple cache list that contains objects for reuse purpose.
+ *	In order to save some per-cpu space the list is singular.
+ *	Even though it is lockless an access has to be protected by the
+ *	per-cpu lock.
+ * @page_cache_work: A work to refill the cache when it is empty
+ * @backoff_page_cache_fill: Delay cache refills
+ * @work_in_progress: Indicates that page_cache_work is running
+ * @hrtimer: A hrtimer for scheduling a page_cache_work
+ * @nr_bkv_objs: number of allocated objects at @bkvcache.
+ *
+ * This is a per-CPU structure.  The reason that it is not included in
+ * the rcu_data structure is to permit this code to be extracted from
+ * the RCU files.  Such extraction could allow further optimization of
+ * the interactions with the slab allocators.
+ */
+struct kfree_rcu_cpu {
+	struct rcu_head *head;
+	struct kvfree_rcu_bulk_data *bkvhead[FREE_N_CHANNELS];
+	struct kfree_rcu_cpu_work krw_arr[KFREE_N_BATCHES];
+	raw_spinlock_t lock;
+	struct delayed_work monitor_work;
+	bool initialized;
+	int count;
+
+	struct delayed_work page_cache_work;
+	atomic_t backoff_page_cache_fill;
+	atomic_t work_in_progress;
+	struct hrtimer hrtimer;
+
+	struct llist_head bkvcache;
+	int nr_bkv_objs;
+};
+
+static DEFINE_PER_CPU(struct kfree_rcu_cpu, krc) = {
+	.lock = __RAW_SPIN_LOCK_UNLOCKED(krc.lock),
+};
+
+static __always_inline void
+debug_rcu_bhead_unqueue(struct kvfree_rcu_bulk_data *bhead)
+{
+#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
+	int i;
+
+	for (i = 0; i < bhead->nr_records; i++)
+		debug_rcu_head_unqueue((struct rcu_head *)(bhead->records[i]));
+#endif
+}
+
+static inline struct kfree_rcu_cpu *
+krc_this_cpu_lock(unsigned long *flags)
+{
+	struct kfree_rcu_cpu *krcp;
+
+	local_irq_save(*flags);	// For safely calling this_cpu_ptr().
+	krcp = this_cpu_ptr(&krc);
+	raw_spin_lock(&krcp->lock);
+
+	return krcp;
+}
+
+static inline void
+krc_this_cpu_unlock(struct kfree_rcu_cpu *krcp, unsigned long flags)
+{
+	raw_spin_unlock_irqrestore(&krcp->lock, flags);
+}
+
+static inline struct kvfree_rcu_bulk_data *
+get_cached_bnode(struct kfree_rcu_cpu *krcp)
+{
+	if (!krcp->nr_bkv_objs)
+		return NULL;
+
+	WRITE_ONCE(krcp->nr_bkv_objs, krcp->nr_bkv_objs - 1);
+	return (struct kvfree_rcu_bulk_data *)
+		llist_del_first(&krcp->bkvcache);
+}
+
+static inline bool
+put_cached_bnode(struct kfree_rcu_cpu *krcp,
+	struct kvfree_rcu_bulk_data *bnode)
+{
+	// Check the limit.
+	if (krcp->nr_bkv_objs >= rcu_min_cached_objs)
+		return false;
+
+	llist_add((struct llist_node *) bnode, &krcp->bkvcache);
+	WRITE_ONCE(krcp->nr_bkv_objs, krcp->nr_bkv_objs + 1);
+	return true;
+}
+
+static int
+drain_page_cache(struct kfree_rcu_cpu *krcp)
+{
+	unsigned long flags;
+	struct llist_node *page_list, *pos, *n;
+	int freed = 0;
+
+	raw_spin_lock_irqsave(&krcp->lock, flags);
+	page_list = llist_del_all(&krcp->bkvcache);
+	WRITE_ONCE(krcp->nr_bkv_objs, 0);
+	raw_spin_unlock_irqrestore(&krcp->lock, flags);
+
+	llist_for_each_safe(pos, n, page_list) {
+		free_page((unsigned long)pos);
+		freed++;
+	}
+
+	return freed;
+}
+
+/*
+ * This function is invoked in workqueue context after a grace period.
+ * It frees all the objects queued on ->bkvhead_free or ->head_free.
+ */
+static void kfree_rcu_work(struct work_struct *work)
+{
+	unsigned long flags;
+	struct kvfree_rcu_bulk_data *bkvhead[FREE_N_CHANNELS], *bnext;
+	struct rcu_head *head, *next;
+	struct kfree_rcu_cpu *krcp;
+	struct kfree_rcu_cpu_work *krwp;
+	int i, j;
+
+	krwp = container_of(to_rcu_work(work),
+			    struct kfree_rcu_cpu_work, rcu_work);
+	krcp = krwp->krcp;
+
+	raw_spin_lock_irqsave(&krcp->lock, flags);
+	// Channels 1 and 2.
+	for (i = 0; i < FREE_N_CHANNELS; i++) {
+		bkvhead[i] = krwp->bkvhead_free[i];
+		krwp->bkvhead_free[i] = NULL;
+	}
+
+	// Channel 3.
+	head = krwp->head_free;
+	krwp->head_free = NULL;
+	raw_spin_unlock_irqrestore(&krcp->lock, flags);
+
+	// Handle the first two channels.
+	for (i = 0; i < FREE_N_CHANNELS; i++) {
+		for (; bkvhead[i]; bkvhead[i] = bnext) {
+			bnext = bkvhead[i]->next;
+			debug_rcu_bhead_unqueue(bkvhead[i]);
+
+			rcu_lock_acquire(&rcu_callback_map);
+			if (i == 0) { // kmalloc() / kfree().
+				trace_rcu_invoke_kfree_bulk_callback(
+					rcu_state.name, bkvhead[i]->nr_records,
+					bkvhead[i]->records);
+
+				kfree_bulk(bkvhead[i]->nr_records,
+					bkvhead[i]->records);
+			} else { // vmalloc() / vfree().
+				for (j = 0; j < bkvhead[i]->nr_records; j++) {
+					trace_rcu_invoke_kvfree_callback(
+						rcu_state.name,
+						bkvhead[i]->records[j], 0);
+
+					vfree(bkvhead[i]->records[j]);
+				}
+			}
+			rcu_lock_release(&rcu_callback_map);
+
+			raw_spin_lock_irqsave(&krcp->lock, flags);
+			if (put_cached_bnode(krcp, bkvhead[i]))
+				bkvhead[i] = NULL;
+			raw_spin_unlock_irqrestore(&krcp->lock, flags);
+
+			if (bkvhead[i])
+				free_page((unsigned long) bkvhead[i]);
+
+			cond_resched_tasks_rcu_qs();
+		}
+	}
+
+	/*
+	 * This is used when the "bulk" path can not be used for the
+	 * double-argument of kvfree_rcu().  This happens when the
+	 * page-cache is empty, which means that objects are instead
+	 * queued on a linked list through their rcu_head structures.
+	 * This list is named "Channel 3".
+	 */
+	for (; head; head = next) {
+		unsigned long offset = (unsigned long)head->func;
+		void *ptr = (void *)head - offset;
+
+		next = head->next;
+		debug_rcu_head_unqueue((struct rcu_head *)ptr);
+		rcu_lock_acquire(&rcu_callback_map);
+		trace_rcu_invoke_kvfree_callback(rcu_state.name, head, offset);
+
+		if (!WARN_ON_ONCE(!__is_kvfree_rcu_offset(offset)))
+			kvfree(ptr);
+
+		rcu_lock_release(&rcu_callback_map);
+		cond_resched_tasks_rcu_qs();
+	}
+}
+
+static bool
+need_offload_krc(struct kfree_rcu_cpu *krcp)
+{
+	int i;
+
+	for (i = 0; i < FREE_N_CHANNELS; i++)
+		if (krcp->bkvhead[i])
+			return true;
+
+	return !!krcp->head;
+}
+
+static bool
+need_wait_for_krwp_work(struct kfree_rcu_cpu_work *krwp)
+{
+	int i;
+
+	for (i = 0; i < FREE_N_CHANNELS; i++)
+		if (krwp->bkvhead_free[i])
+			return true;
+
+	return !!krwp->head_free;
+}
+
+static void
+schedule_delayed_monitor_work(struct kfree_rcu_cpu *krcp)
+{
+	long delay, delay_left;
+
+	delay = READ_ONCE(krcp->count) >= KVFREE_BULK_MAX_ENTR ? 1:KFREE_DRAIN_JIFFIES;
+	if (delayed_work_pending(&krcp->monitor_work)) {
+		delay_left = krcp->monitor_work.timer.expires - jiffies;
+		if (delay < delay_left)
+			mod_delayed_work(system_wq, &krcp->monitor_work, delay);
+		return;
+	}
+	queue_delayed_work(system_wq, &krcp->monitor_work, delay);
+}
+
+/*
+ * This function is invoked after the KFREE_DRAIN_JIFFIES timeout.
+ */
+static void kfree_rcu_monitor(struct work_struct *work)
+{
+	struct kfree_rcu_cpu *krcp = container_of(work,
+		struct kfree_rcu_cpu, monitor_work.work);
+	unsigned long flags;
+	int i, j;
+
+	raw_spin_lock_irqsave(&krcp->lock, flags);
+
+	// Attempt to start a new batch.
+	for (i = 0; i < KFREE_N_BATCHES; i++) {
+		struct kfree_rcu_cpu_work *krwp = &(krcp->krw_arr[i]);
+
+		// Try to detach bulk_head or head and attach it, only when
+		// all channels are free.  Any channel is not free means at krwp
+		// there is on-going rcu work to handle krwp's free business.
+		if (need_wait_for_krwp_work(krwp))
+			continue;
+
+		if (need_offload_krc(krcp)) {
+			// Channel 1 corresponds to the SLAB-pointer bulk path.
+			// Channel 2 corresponds to vmalloc-pointer bulk path.
+			for (j = 0; j < FREE_N_CHANNELS; j++) {
+				if (!krwp->bkvhead_free[j]) {
+					krwp->bkvhead_free[j] = krcp->bkvhead[j];
+					krcp->bkvhead[j] = NULL;
+				}
+			}
+
+			// Channel 3 corresponds to both SLAB and vmalloc
+			// objects queued on the linked list.
+			if (!krwp->head_free) {
+				krwp->head_free = krcp->head;
+				krcp->head = NULL;
+			}
+
+			WRITE_ONCE(krcp->count, 0);
+
+			// One work is per one batch, so there are three
+			// "free channels", the batch can handle. It can
+			// be that the work is in the pending state when
+			// channels have been detached following by each
+			// other.
+			queue_rcu_work(system_wq, &krwp->rcu_work);
+		}
+	}
+
+	// If there is nothing to detach, it means that our job is
+	// successfully done here. In case of having at least one
+	// of the channels that is still busy we should rearm the
+	// work to repeat an attempt. Because previous batches are
+	// still in progress.
+	if (need_offload_krc(krcp))
+		schedule_delayed_monitor_work(krcp);
+
+	raw_spin_unlock_irqrestore(&krcp->lock, flags);
+}
+
+static enum hrtimer_restart
+schedule_page_work_fn(struct hrtimer *t)
+{
+	struct kfree_rcu_cpu *krcp =
+		container_of(t, struct kfree_rcu_cpu, hrtimer);
+
+	queue_delayed_work(system_highpri_wq, &krcp->page_cache_work, 0);
+	return HRTIMER_NORESTART;
+}
+
+static void fill_page_cache_func(struct work_struct *work)
+{
+	struct kvfree_rcu_bulk_data *bnode;
+	struct kfree_rcu_cpu *krcp =
+		container_of(work, struct kfree_rcu_cpu,
+			page_cache_work.work);
+	unsigned long flags;
+	int nr_pages;
+	bool pushed;
+	int i;
+
+	nr_pages = atomic_read(&krcp->backoff_page_cache_fill) ?
+		1 : rcu_min_cached_objs;
+
+	for (i = 0; i < nr_pages; i++) {
+		bnode = (struct kvfree_rcu_bulk_data *)
+			__get_free_page(GFP_KERNEL | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
+
+		if (!bnode)
+			break;
+
+		raw_spin_lock_irqsave(&krcp->lock, flags);
+		pushed = put_cached_bnode(krcp, bnode);
+		raw_spin_unlock_irqrestore(&krcp->lock, flags);
+
+		if (!pushed) {
+			free_page((unsigned long) bnode);
+			break;
+		}
+	}
+
+	atomic_set(&krcp->work_in_progress, 0);
+	atomic_set(&krcp->backoff_page_cache_fill, 0);
+}
+
+static void
+run_page_cache_worker(struct kfree_rcu_cpu *krcp)
+{
+	if (rcu_scheduler_active == RCU_SCHEDULER_RUNNING &&
+			!atomic_xchg(&krcp->work_in_progress, 1)) {
+		if (atomic_read(&krcp->backoff_page_cache_fill)) {
+			queue_delayed_work(system_wq,
+				&krcp->page_cache_work,
+					msecs_to_jiffies(rcu_delay_page_cache_fill_msec));
+		} else {
+			hrtimer_init(&krcp->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+			krcp->hrtimer.function = schedule_page_work_fn;
+			hrtimer_start(&krcp->hrtimer, 0, HRTIMER_MODE_REL);
+		}
+	}
+}
+
+// Record ptr in a page managed by krcp, with the pre-krc_this_cpu_lock()
+// state specified by flags.  If can_alloc is true, the caller must
+// be schedulable and not be holding any locks or mutexes that might be
+// acquired by the memory allocator or anything that it might invoke.
+// Returns true if ptr was successfully recorded, else the caller must
+// use a fallback.
+static inline bool
+add_ptr_to_bulk_krc_lock(struct kfree_rcu_cpu **krcp,
+	unsigned long *flags, void *ptr, bool can_alloc)
+{
+	struct kvfree_rcu_bulk_data *bnode;
+	int idx;
+
+	*krcp = krc_this_cpu_lock(flags);
+	if (unlikely(!(*krcp)->initialized))
+		return false;
+
+	idx = !!is_vmalloc_addr(ptr);
+
+	/* Check if a new block is required. */
+	if (!(*krcp)->bkvhead[idx] ||
+			(*krcp)->bkvhead[idx]->nr_records == KVFREE_BULK_MAX_ENTR) {
+		bnode = get_cached_bnode(*krcp);
+		if (!bnode && can_alloc) {
+			krc_this_cpu_unlock(*krcp, *flags);
+
+			// __GFP_NORETRY - allows a light-weight direct reclaim
+			// what is OK from minimizing of fallback hitting point of
+			// view. Apart of that it forbids any OOM invoking what is
+			// also beneficial since we are about to release memory soon.
+			//
+			// __GFP_NOMEMALLOC - prevents from consuming of all the
+			// memory reserves. Please note we have a fallback path.
+			//
+			// __GFP_NOWARN - it is supposed that an allocation can
+			// be failed under low memory or high memory pressure
+			// scenarios.
+			bnode = (struct kvfree_rcu_bulk_data *)
+				__get_free_page(GFP_KERNEL | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
+			*krcp = krc_this_cpu_lock(flags);
+		}
+
+		if (!bnode)
+			return false;
+
+		/* Initialize the new block. */
+		bnode->nr_records = 0;
+		bnode->next = (*krcp)->bkvhead[idx];
+
+		/* Attach it to the head. */
+		(*krcp)->bkvhead[idx] = bnode;
+	}
+
+	/* Finally insert. */
+	(*krcp)->bkvhead[idx]->records
+		[(*krcp)->bkvhead[idx]->nr_records++] = ptr;
+
+	return true;
+}
+
+/*
+ * Queue a request for lazy invocation of the appropriate free routine
+ * after a grace period.  Please note that three paths are maintained,
+ * two for the common case using arrays of pointers and a third one that
+ * is used only when the main paths cannot be used, for example, due to
+ * memory pressure.
+ *
+ * Each kvfree_call_rcu() request is added to a batch. The batch will be drained
+ * every KFREE_DRAIN_JIFFIES number of jiffies. All the objects in the batch will
+ * be free'd in workqueue context. This allows us to: batch requests together to
+ * reduce the number of grace periods during heavy kfree_rcu()/kvfree_rcu() load.
+ */
+void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
+{
+	unsigned long flags;
+	struct kfree_rcu_cpu *krcp;
+	bool success;
+	void *ptr;
+
+	if (head) {
+		ptr = (void *) head - (unsigned long) func;
+	} else {
+		/*
+		 * Please note there is a limitation for the head-less
+		 * variant, that is why there is a clear rule for such
+		 * objects: it can be used from might_sleep() context
+		 * only. For other places please embed an rcu_head to
+		 * your data.
+		 */
+		might_sleep();
+		ptr = (unsigned long *) func;
+	}
+
+	// Queue the object but don't yet schedule the batch.
+	if (debug_rcu_head_queue(ptr)) {
+		// Probable double kfree_rcu(), just leak.
+		WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n",
+			  __func__, head);
+
+		// Mark as success and leave.
+		return;
+	}
+
+	kasan_record_aux_stack_noalloc(ptr);
+	success = add_ptr_to_bulk_krc_lock(&krcp, &flags, ptr, !head);
+	if (!success) {
+		run_page_cache_worker(krcp);
+
+		if (head == NULL)
+			// Inline if kvfree_rcu(one_arg) call.
+			goto unlock_return;
+
+		head->func = func;
+		head->next = krcp->head;
+		krcp->head = head;
+		success = true;
+	}
+
+	WRITE_ONCE(krcp->count, krcp->count + 1);
+
+	/*
+	 * The kvfree_rcu() caller considers the pointer freed at this point
+	 * and likely removes any references to it. Since the actual slab
+	 * freeing (and kmemleak_free()) is deferred, tell kmemleak to ignore
+	 * this object (no scanning or false positives reporting).
+	 */
+	kmemleak_ignore(ptr);
+
+	// Set timer to drain after KFREE_DRAIN_JIFFIES.
+	if (rcu_scheduler_active == RCU_SCHEDULER_RUNNING)
+		schedule_delayed_monitor_work(krcp);
+
+unlock_return:
+	krc_this_cpu_unlock(krcp, flags);
+
+	/*
+	 * Inline kvfree() after synchronize_rcu(). We can do
+	 * it from might_sleep() context only, so the current
+	 * CPU can pass the QS state.
+	 */
+	if (!success) {
+		debug_rcu_head_unqueue((struct rcu_head *) ptr);
+		synchronize_rcu();
+		kvfree(ptr);
+	}
+}
+EXPORT_SYMBOL_GPL(kvfree_call_rcu);
+
+static unsigned long
+kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
+{
+	int cpu;
+	unsigned long count = 0;
+
+	/* Snapshot count of all CPUs */
+	for_each_possible_cpu(cpu) {
+		struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu);
+
+		count += READ_ONCE(krcp->count);
+		count += READ_ONCE(krcp->nr_bkv_objs);
+		atomic_set(&krcp->backoff_page_cache_fill, 1);
+	}
+
+	return count == 0 ? SHRINK_EMPTY : count;
+}
+
+static unsigned long
+kfree_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
+{
+	int cpu, freed = 0;
+
+	for_each_possible_cpu(cpu) {
+		int count;
+		struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu);
+
+		count = krcp->count;
+		count += drain_page_cache(krcp);
+		kfree_rcu_monitor(&krcp->monitor_work.work);
+
+		sc->nr_to_scan -= count;
+		freed += count;
+
+		if (sc->nr_to_scan <= 0)
+			break;
+	}
+
+	return freed == 0 ? SHRINK_STOP : freed;
+}
+
+static struct shrinker kfree_rcu_shrinker = {
+	.count_objects = kfree_rcu_shrink_count,
+	.scan_objects = kfree_rcu_shrink_scan,
+	.batch = 0,
+	.seeks = DEFAULT_SEEKS,
+};
+
+void __init kfree_rcu_scheduler_running(void)
+{
+	int cpu;
+	unsigned long flags;
+
+	for_each_possible_cpu(cpu) {
+		struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu);
+
+		raw_spin_lock_irqsave(&krcp->lock, flags);
+		if (need_offload_krc(krcp))
+			schedule_delayed_monitor_work(krcp);
+		raw_spin_unlock_irqrestore(&krcp->lock, flags);
+	}
+}
+
+/*
+ * During early boot, any blocking grace-period wait automatically
+ * implies a grace period.
+ *
+ * Later on, this could in theory be the case for kernels built with
+ * CONFIG_SMP=y && CONFIG_PREEMPTION=y running on a single CPU, but this
+ * is not a common case.  Furthermore, this optimization would cause
+ * the rcu_gp_oldstate structure to expand by 50%, so this potential
+ * grace-period optimization is ignored once the scheduler is running.
+ */
+static int rcu_blocking_is_gp(void)
+{
+	if (rcu_scheduler_active != RCU_SCHEDULER_INACTIVE)
+		return false;
+	might_sleep();  /* Check for RCU read-side critical section. */
+	return true;
+}
+
+/**
+ * synchronize_rcu - wait until a grace period has elapsed.
+ *
+ * Control will return to the caller some time after a full grace
+ * period has elapsed, in other words after all currently executing RCU
+ * read-side critical sections have completed.  Note, however, that
+ * upon return from synchronize_rcu(), the caller might well be executing
+ * concurrently with new RCU read-side critical sections that began while
+ * synchronize_rcu() was waiting.
+ *
+ * RCU read-side critical sections are delimited by rcu_read_lock()
+ * and rcu_read_unlock(), and may be nested.  In addition, but only in
+ * v5.0 and later, regions of code across which interrupts, preemption,
+ * or softirqs have been disabled also serve as RCU read-side critical
+ * sections.  This includes hardware interrupt handlers, softirq handlers,
+ * and NMI handlers.
+ *
+ * Note that this guarantee implies further memory-ordering guarantees.
+ * On systems with more than one CPU, when synchronize_rcu() returns,
+ * each CPU is guaranteed to have executed a full memory barrier since
+ * the end of its last RCU read-side critical section whose beginning
+ * preceded the call to synchronize_rcu().  In addition, each CPU having
+ * an RCU read-side critical section that extends beyond the return from
+ * synchronize_rcu() is guaranteed to have executed a full memory barrier
+ * after the beginning of synchronize_rcu() and before the beginning of
+ * that RCU read-side critical section.  Note that these guarantees include
+ * CPUs that are offline, idle, or executing in user mode, as well as CPUs
+ * that are executing in the kernel.
+ *
+ * Furthermore, if CPU A invoked synchronize_rcu(), which returned
+ * to its caller on CPU B, then both CPU A and CPU B are guaranteed
+ * to have executed a full memory barrier during the execution of
+ * synchronize_rcu() -- even if CPU A and CPU B are the same CPU (but
+ * again only if the system has more than one CPU).
+ *
+ * Implementation of these memory-ordering guarantees is described here:
+ * Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst.
+ */
+void synchronize_rcu(void)
+{
+	unsigned long flags;
+	struct rcu_node *rnp;
+
+	RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+			 lock_is_held(&rcu_lock_map) ||
+			 lock_is_held(&rcu_sched_lock_map),
+			 "Illegal synchronize_rcu() in RCU read-side critical section");
+	if (!rcu_blocking_is_gp()) {
+		if (rcu_gp_is_expedited())
+			synchronize_rcu_expedited();
+		else
+			wait_rcu_gp(call_rcu);
+		return;
+	}
+
+	// Context allows vacuous grace periods.
+	// Note well that this code runs with !PREEMPT && !SMP.
+	// In addition, all code that advances grace periods runs at
+	// process level.  Therefore, this normal GP overlaps with other
+	// normal GPs only by being fully nested within them, which allows
+	// reuse of ->gp_seq_polled_snap.
+	rcu_poll_gp_seq_start_unlocked(&rcu_state.gp_seq_polled_snap);
+	rcu_poll_gp_seq_end_unlocked(&rcu_state.gp_seq_polled_snap);
+
+	// Update the normal grace-period counters to record
+	// this grace period, but only those used by the boot CPU.
+	// The rcu_scheduler_starting() will take care of the rest of
+	// these counters.
+	local_irq_save(flags);
+	WARN_ON_ONCE(num_online_cpus() > 1);
+	rcu_state.gp_seq += (1 << RCU_SEQ_CTR_SHIFT);
+	for (rnp = this_cpu_ptr(&rcu_data)->mynode; rnp; rnp = rnp->parent)
+		rnp->gp_seq_needed = rnp->gp_seq = rcu_state.gp_seq;
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(synchronize_rcu);
+
+/**
+ * get_completed_synchronize_rcu_full - Return a full pre-completed polled state cookie
+ * @rgosp: Place to put state cookie
+ *
+ * Stores into @rgosp a value that will always be treated by functions
+ * like poll_state_synchronize_rcu_full() as a cookie whose grace period
+ * has already completed.
+ */
+void get_completed_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
+{
+	rgosp->rgos_norm = RCU_GET_STATE_COMPLETED;
+	rgosp->rgos_exp = RCU_GET_STATE_COMPLETED;
+}
+EXPORT_SYMBOL_GPL(get_completed_synchronize_rcu_full);
+
+/**
+ * get_state_synchronize_rcu - Snapshot current RCU state
+ *
+ * Returns a cookie that is used by a later call to cond_synchronize_rcu()
+ * or poll_state_synchronize_rcu() to determine whether or not a full
+ * grace period has elapsed in the meantime.
+ */
+unsigned long get_state_synchronize_rcu(void)
+{
+	/*
+	 * Any prior manipulation of RCU-protected data must happen
+	 * before the load from ->gp_seq.
+	 */
+	smp_mb();  /* ^^^ */
+	return rcu_seq_snap(&rcu_state.gp_seq_polled);
+}
+EXPORT_SYMBOL_GPL(get_state_synchronize_rcu);
+
+/**
+ * get_state_synchronize_rcu_full - Snapshot RCU state, both normal and expedited
+ * @rgosp: location to place combined normal/expedited grace-period state
+ *
+ * Places the normal and expedited grace-period states in @rgosp.  This
+ * state value can be passed to a later call to cond_synchronize_rcu_full()
+ * or poll_state_synchronize_rcu_full() to determine whether or not a
+ * grace period (whether normal or expedited) has elapsed in the meantime.
+ * The rcu_gp_oldstate structure takes up twice the memory of an unsigned
+ * long, but is guaranteed to see all grace periods.  In contrast, the
+ * combined state occupies less memory, but can sometimes fail to take
+ * grace periods into account.
+ *
+ * This does not guarantee that the needed grace period will actually
+ * start.
+ */
+void get_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
+{
+	struct rcu_node *rnp = rcu_get_root();
+
+	/*
+	 * Any prior manipulation of RCU-protected data must happen
+	 * before the loads from ->gp_seq and ->expedited_sequence.
+	 */
+	smp_mb();  /* ^^^ */
+	rgosp->rgos_norm = rcu_seq_snap(&rnp->gp_seq);
+	rgosp->rgos_exp = rcu_seq_snap(&rcu_state.expedited_sequence);
+}
+EXPORT_SYMBOL_GPL(get_state_synchronize_rcu_full);
+
+/*
+ * Helper function for start_poll_synchronize_rcu() and
+ * start_poll_synchronize_rcu_full().
+ */
+static void start_poll_synchronize_rcu_common(void)
+{
+	unsigned long flags;
+	bool needwake;
+	struct rcu_data *rdp;
+	struct rcu_node *rnp;
+
+	lockdep_assert_irqs_enabled();
+	local_irq_save(flags);
+	rdp = this_cpu_ptr(&rcu_data);
+	rnp = rdp->mynode;
+	raw_spin_lock_rcu_node(rnp); // irqs already disabled.
+	// Note it is possible for a grace period to have elapsed between
+	// the above call to get_state_synchronize_rcu() and the below call
+	// to rcu_seq_snap.  This is OK, the worst that happens is that we
+	// get a grace period that no one needed.  These accesses are ordered
+	// by smp_mb(), and we are accessing them in the opposite order
+	// from which they are updated at grace-period start, as required.
+	needwake = rcu_start_this_gp(rnp, rdp, rcu_seq_snap(&rcu_state.gp_seq));
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	if (needwake)
+		rcu_gp_kthread_wake();
+}
+
+/**
+ * start_poll_synchronize_rcu - Snapshot and start RCU grace period
+ *
+ * Returns a cookie that is used by a later call to cond_synchronize_rcu()
+ * or poll_state_synchronize_rcu() to determine whether or not a full
+ * grace period has elapsed in the meantime.  If the needed grace period
+ * is not already slated to start, notifies RCU core of the need for that
+ * grace period.
+ *
+ * Interrupts must be enabled for the case where it is necessary to awaken
+ * the grace-period kthread.
+ */
+unsigned long start_poll_synchronize_rcu(void)
+{
+	unsigned long gp_seq = get_state_synchronize_rcu();
+
+	start_poll_synchronize_rcu_common();
+	return gp_seq;
+}
+EXPORT_SYMBOL_GPL(start_poll_synchronize_rcu);
+
+/**
+ * start_poll_synchronize_rcu_full - Take a full snapshot and start RCU grace period
+ * @rgosp: value from get_state_synchronize_rcu_full() or start_poll_synchronize_rcu_full()
+ *
+ * Places the normal and expedited grace-period states in *@rgos.  This
+ * state value can be passed to a later call to cond_synchronize_rcu_full()
+ * or poll_state_synchronize_rcu_full() to determine whether or not a
+ * grace period (whether normal or expedited) has elapsed in the meantime.
+ * If the needed grace period is not already slated to start, notifies
+ * RCU core of the need for that grace period.
+ *
+ * Interrupts must be enabled for the case where it is necessary to awaken
+ * the grace-period kthread.
+ */
+void start_poll_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
+{
+	get_state_synchronize_rcu_full(rgosp);
+
+	start_poll_synchronize_rcu_common();
+}
+EXPORT_SYMBOL_GPL(start_poll_synchronize_rcu_full);
+
+/**
+ * poll_state_synchronize_rcu - Has the specified RCU grace period completed?
+ * @oldstate: value from get_state_synchronize_rcu() or start_poll_synchronize_rcu()
+ *
+ * If a full RCU grace period has elapsed since the earlier call from
+ * which @oldstate was obtained, return @true, otherwise return @false.
+ * If @false is returned, it is the caller's responsibility to invoke this
+ * function later on until it does return @true.  Alternatively, the caller
+ * can explicitly wait for a grace period, for example, by passing @oldstate
+ * to cond_synchronize_rcu() or by directly invoking synchronize_rcu().
+ *
+ * Yes, this function does not take counter wrap into account.
+ * But counter wrap is harmless.  If the counter wraps, we have waited for
+ * more than a billion grace periods (and way more on a 64-bit system!).
+ * Those needing to keep old state values for very long time periods
+ * (many hours even on 32-bit systems) should check them occasionally and
+ * either refresh them or set a flag indicating that the grace period has
+ * completed.  Alternatively, they can use get_completed_synchronize_rcu()
+ * to get a guaranteed-completed grace-period state.
+ *
+ * This function provides the same memory-ordering guarantees that
+ * would be provided by a synchronize_rcu() that was invoked at the call
+ * to the function that provided @oldstate, and that returned at the end
+ * of this function.
+ */
+bool poll_state_synchronize_rcu(unsigned long oldstate)
+{
+	if (oldstate == RCU_GET_STATE_COMPLETED ||
+	    rcu_seq_done_exact(&rcu_state.gp_seq_polled, oldstate)) {
+		smp_mb(); /* Ensure GP ends before subsequent accesses. */
+		return true;
+	}
+	return false;
+}
+EXPORT_SYMBOL_GPL(poll_state_synchronize_rcu);
+
+/**
+ * poll_state_synchronize_rcu_full - Has the specified RCU grace period completed?
+ * @rgosp: value from get_state_synchronize_rcu_full() or start_poll_synchronize_rcu_full()
+ *
+ * If a full RCU grace period has elapsed since the earlier call from
+ * which *rgosp was obtained, return @true, otherwise return @false.
+ * If @false is returned, it is the caller's responsibility to invoke this
+ * function later on until it does return @true.  Alternatively, the caller
+ * can explicitly wait for a grace period, for example, by passing @rgosp
+ * to cond_synchronize_rcu() or by directly invoking synchronize_rcu().
+ *
+ * Yes, this function does not take counter wrap into account.
+ * But counter wrap is harmless.  If the counter wraps, we have waited
+ * for more than a billion grace periods (and way more on a 64-bit
+ * system!).  Those needing to keep rcu_gp_oldstate values for very
+ * long time periods (many hours even on 32-bit systems) should check
+ * them occasionally and either refresh them or set a flag indicating
+ * that the grace period has completed.  Alternatively, they can use
+ * get_completed_synchronize_rcu_full() to get a guaranteed-completed
+ * grace-period state.
+ *
+ * This function provides the same memory-ordering guarantees that would
+ * be provided by a synchronize_rcu() that was invoked at the call to
+ * the function that provided @rgosp, and that returned at the end of this
+ * function.  And this guarantee requires that the root rcu_node structure's
+ * ->gp_seq field be checked instead of that of the rcu_state structure.
+ * The problem is that the just-ending grace-period's callbacks can be
+ * invoked between the time that the root rcu_node structure's ->gp_seq
+ * field is updated and the time that the rcu_state structure's ->gp_seq
+ * field is updated.  Therefore, if a single synchronize_rcu() is to
+ * cause a subsequent poll_state_synchronize_rcu_full() to return @true,
+ * then the root rcu_node structure is the one that needs to be polled.
+ */
+bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
+{
+	struct rcu_node *rnp = rcu_get_root();
+
+	smp_mb(); // Order against root rcu_node structure grace-period cleanup.
+	if (rgosp->rgos_norm == RCU_GET_STATE_COMPLETED ||
+	    rcu_seq_done_exact(&rnp->gp_seq, rgosp->rgos_norm) ||
+	    rgosp->rgos_exp == RCU_GET_STATE_COMPLETED ||
+	    rcu_seq_done_exact(&rcu_state.expedited_sequence, rgosp->rgos_exp)) {
+		smp_mb(); /* Ensure GP ends before subsequent accesses. */
+		return true;
+	}
+	return false;
+}
+EXPORT_SYMBOL_GPL(poll_state_synchronize_rcu_full);
+
+/**
+ * cond_synchronize_rcu - Conditionally wait for an RCU grace period
+ * @oldstate: value from get_state_synchronize_rcu(), start_poll_synchronize_rcu(), or start_poll_synchronize_rcu_expedited()
+ *
+ * If a full RCU grace period has elapsed since the earlier call to
+ * get_state_synchronize_rcu() or start_poll_synchronize_rcu(), just return.
+ * Otherwise, invoke synchronize_rcu() to wait for a full grace period.
+ *
+ * Yes, this function does not take counter wrap into account.
+ * But counter wrap is harmless.  If the counter wraps, we have waited for
+ * more than 2 billion grace periods (and way more on a 64-bit system!),
+ * so waiting for a couple of additional grace periods should be just fine.
+ *
+ * This function provides the same memory-ordering guarantees that
+ * would be provided by a synchronize_rcu() that was invoked at the call
+ * to the function that provided @oldstate and that returned at the end
+ * of this function.
+ */
+void cond_synchronize_rcu(unsigned long oldstate)
+{
+	if (!poll_state_synchronize_rcu(oldstate))
+		synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(cond_synchronize_rcu);
+
+/**
+ * cond_synchronize_rcu_full - Conditionally wait for an RCU grace period
+ * @rgosp: value from get_state_synchronize_rcu_full(), start_poll_synchronize_rcu_full(), or start_poll_synchronize_rcu_expedited_full()
+ *
+ * If a full RCU grace period has elapsed since the call to
+ * get_state_synchronize_rcu_full(), start_poll_synchronize_rcu_full(),
+ * or start_poll_synchronize_rcu_expedited_full() from which @rgosp was
+ * obtained, just return.  Otherwise, invoke synchronize_rcu() to wait
+ * for a full grace period.
+ *
+ * Yes, this function does not take counter wrap into account.
+ * But counter wrap is harmless.  If the counter wraps, we have waited for
+ * more than 2 billion grace periods (and way more on a 64-bit system!),
+ * so waiting for a couple of additional grace periods should be just fine.
+ *
+ * This function provides the same memory-ordering guarantees that
+ * would be provided by a synchronize_rcu() that was invoked at the call
+ * to the function that provided @rgosp and that returned at the end of
+ * this function.
+ */
+void cond_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
+{
+	if (!poll_state_synchronize_rcu_full(rgosp))
+		synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(cond_synchronize_rcu_full);
+
+/*
+ * Check to see if there is any immediate RCU-related work to be done by
+ * the current CPU, returning 1 if so and zero otherwise.  The checks are
+ * in order of increasing expense: checks that can be carried out against
+ * CPU-local state are performed first.  However, we must check for CPU
+ * stalls first, else we might not get a chance.
+ */
+static int rcu_pending(int user)
+{
+	bool gp_in_progress;
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
+	struct rcu_node *rnp = rdp->mynode;
+
+	lockdep_assert_irqs_disabled();
+
+	/* Check for CPU stalls, if enabled. */
+	check_cpu_stall(rdp);
+
+	/* Does this CPU need a deferred NOCB wakeup? */
+	if (rcu_nocb_need_deferred_wakeup(rdp, RCU_NOCB_WAKE))
+		return 1;
+
+	/* Is this a nohz_full CPU in userspace or idle?  (Ignore RCU if so.) */
+	if ((user || rcu_is_cpu_rrupt_from_idle()) && rcu_nohz_full_cpu())
+		return 0;
+
+	/* Is the RCU core waiting for a quiescent state from this CPU? */
+	gp_in_progress = rcu_gp_in_progress();
+	if (rdp->core_needs_qs && !rdp->cpu_no_qs.b.norm && gp_in_progress)
+		return 1;
+
+	/* Does this CPU have callbacks ready to invoke? */
+	if (!rcu_rdp_is_offloaded(rdp) &&
+	    rcu_segcblist_ready_cbs(&rdp->cblist))
+		return 1;
+
+	/* Has RCU gone idle with this CPU needing another grace period? */
+	if (!gp_in_progress && rcu_segcblist_is_enabled(&rdp->cblist) &&
+	    !rcu_rdp_is_offloaded(rdp) &&
+	    !rcu_segcblist_restempty(&rdp->cblist, RCU_NEXT_READY_TAIL))
+		return 1;
+
+	/* Have RCU grace period completed or started?  */
+	if (rcu_seq_current(&rnp->gp_seq) != rdp->gp_seq ||
+	    unlikely(READ_ONCE(rdp->gpwrap))) /* outside lock */
+		return 1;
+
+	/* nothing to do */
+	return 0;
+}
+
+/*
+ * Helper function for rcu_barrier() tracing.  If tracing is disabled,
+ * the compiler is expected to optimize this away.
+ */
+static void rcu_barrier_trace(const char *s, int cpu, unsigned long done)
+{
+	trace_rcu_barrier(rcu_state.name, s, cpu,
+			  atomic_read(&rcu_state.barrier_cpu_count), done);
+}
+
+/*
+ * RCU callback function for rcu_barrier().  If we are last, wake
+ * up the task executing rcu_barrier().
+ *
+ * Note that the value of rcu_state.barrier_sequence must be captured
+ * before the atomic_dec_and_test().  Otherwise, if this CPU is not last,
+ * other CPUs might count the value down to zero before this CPU gets
+ * around to invoking rcu_barrier_trace(), which might result in bogus
+ * data from the next instance of rcu_barrier().
+ */
+static void rcu_barrier_callback(struct rcu_head *rhp)
+{
+	unsigned long __maybe_unused s = rcu_state.barrier_sequence;
+
+	if (atomic_dec_and_test(&rcu_state.barrier_cpu_count)) {
+		rcu_barrier_trace(TPS("LastCB"), -1, s);
+		complete(&rcu_state.barrier_completion);
+	} else {
+		rcu_barrier_trace(TPS("CB"), -1, s);
+	}
+}
+
+/*
+ * If needed, entrain an rcu_barrier() callback on rdp->cblist.
+ */
+static void rcu_barrier_entrain(struct rcu_data *rdp)
+{
+	unsigned long gseq = READ_ONCE(rcu_state.barrier_sequence);
+	unsigned long lseq = READ_ONCE(rdp->barrier_seq_snap);
+
+	lockdep_assert_held(&rcu_state.barrier_lock);
+	if (rcu_seq_state(lseq) || !rcu_seq_state(gseq) || rcu_seq_ctr(lseq) != rcu_seq_ctr(gseq))
+		return;
+	rcu_barrier_trace(TPS("IRQ"), -1, rcu_state.barrier_sequence);
+	rdp->barrier_head.func = rcu_barrier_callback;
+	debug_rcu_head_queue(&rdp->barrier_head);
+	rcu_nocb_lock(rdp);
+	WARN_ON_ONCE(!rcu_nocb_flush_bypass(rdp, NULL, jiffies));
+	if (rcu_segcblist_entrain(&rdp->cblist, &rdp->barrier_head)) {
+		atomic_inc(&rcu_state.barrier_cpu_count);
+	} else {
+		debug_rcu_head_unqueue(&rdp->barrier_head);
+		rcu_barrier_trace(TPS("IRQNQ"), -1, rcu_state.barrier_sequence);
+	}
+	rcu_nocb_unlock(rdp);
+	smp_store_release(&rdp->barrier_seq_snap, gseq);
+}
+
+/*
+ * Called with preemption disabled, and from cross-cpu IRQ context.
+ */
+static void rcu_barrier_handler(void *cpu_in)
+{
+	uintptr_t cpu = (uintptr_t)cpu_in;
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+
+	lockdep_assert_irqs_disabled();
+	WARN_ON_ONCE(cpu != rdp->cpu);
+	WARN_ON_ONCE(cpu != smp_processor_id());
+	raw_spin_lock(&rcu_state.barrier_lock);
+	rcu_barrier_entrain(rdp);
+	raw_spin_unlock(&rcu_state.barrier_lock);
+}
+
+/**
+ * rcu_barrier - Wait until all in-flight call_rcu() callbacks complete.
+ *
+ * Note that this primitive does not necessarily wait for an RCU grace period
+ * to complete.  For example, if there are no RCU callbacks queued anywhere
+ * in the system, then rcu_barrier() is within its rights to return
+ * immediately, without waiting for anything, much less an RCU grace period.
+ */
+void rcu_barrier(void)
+{
+	uintptr_t cpu;
+	unsigned long flags;
+	unsigned long gseq;
+	struct rcu_data *rdp;
+	unsigned long s = rcu_seq_snap(&rcu_state.barrier_sequence);
+
+	rcu_barrier_trace(TPS("Begin"), -1, s);
+
+	/* Take mutex to serialize concurrent rcu_barrier() requests. */
+	mutex_lock(&rcu_state.barrier_mutex);
+
+	/* Did someone else do our work for us? */
+	if (rcu_seq_done(&rcu_state.barrier_sequence, s)) {
+		rcu_barrier_trace(TPS("EarlyExit"), -1, rcu_state.barrier_sequence);
+		smp_mb(); /* caller's subsequent code after above check. */
+		mutex_unlock(&rcu_state.barrier_mutex);
+		return;
+	}
+
+	/* Mark the start of the barrier operation. */
+	raw_spin_lock_irqsave(&rcu_state.barrier_lock, flags);
+	rcu_seq_start(&rcu_state.barrier_sequence);
+	gseq = rcu_state.barrier_sequence;
+	rcu_barrier_trace(TPS("Inc1"), -1, rcu_state.barrier_sequence);
+
+	/*
+	 * Initialize the count to two rather than to zero in order
+	 * to avoid a too-soon return to zero in case of an immediate
+	 * invocation of the just-enqueued callback (or preemption of
+	 * this task).  Exclude CPU-hotplug operations to ensure that no
+	 * offline non-offloaded CPU has callbacks queued.
+	 */
+	init_completion(&rcu_state.barrier_completion);
+	atomic_set(&rcu_state.barrier_cpu_count, 2);
+	raw_spin_unlock_irqrestore(&rcu_state.barrier_lock, flags);
+
+	/*
+	 * Force each CPU with callbacks to register a new callback.
+	 * When that callback is invoked, we will know that all of the
+	 * corresponding CPU's preceding callbacks have been invoked.
+	 */
+	for_each_possible_cpu(cpu) {
+		rdp = per_cpu_ptr(&rcu_data, cpu);
+retry:
+		if (smp_load_acquire(&rdp->barrier_seq_snap) == gseq)
+			continue;
+		raw_spin_lock_irqsave(&rcu_state.barrier_lock, flags);
+		if (!rcu_segcblist_n_cbs(&rdp->cblist)) {
+			WRITE_ONCE(rdp->barrier_seq_snap, gseq);
+			raw_spin_unlock_irqrestore(&rcu_state.barrier_lock, flags);
+			rcu_barrier_trace(TPS("NQ"), cpu, rcu_state.barrier_sequence);
+			continue;
+		}
+		if (!rcu_rdp_cpu_online(rdp)) {
+			rcu_barrier_entrain(rdp);
+			WARN_ON_ONCE(READ_ONCE(rdp->barrier_seq_snap) != gseq);
+			raw_spin_unlock_irqrestore(&rcu_state.barrier_lock, flags);
+			rcu_barrier_trace(TPS("OfflineNoCBQ"), cpu, rcu_state.barrier_sequence);
+			continue;
+		}
+		raw_spin_unlock_irqrestore(&rcu_state.barrier_lock, flags);
+		if (smp_call_function_single(cpu, rcu_barrier_handler, (void *)cpu, 1)) {
+			schedule_timeout_uninterruptible(1);
+			goto retry;
+		}
+		WARN_ON_ONCE(READ_ONCE(rdp->barrier_seq_snap) != gseq);
+		rcu_barrier_trace(TPS("OnlineQ"), cpu, rcu_state.barrier_sequence);
+	}
+
+	/*
+	 * Now that we have an rcu_barrier_callback() callback on each
+	 * CPU, and thus each counted, remove the initial count.
+	 */
+	if (atomic_sub_and_test(2, &rcu_state.barrier_cpu_count))
+		complete(&rcu_state.barrier_completion);
+
+	/* Wait for all rcu_barrier_callback() callbacks to be invoked. */
+	wait_for_completion(&rcu_state.barrier_completion);
+
+	/* Mark the end of the barrier operation. */
+	rcu_barrier_trace(TPS("Inc2"), -1, rcu_state.barrier_sequence);
+	rcu_seq_end(&rcu_state.barrier_sequence);
+	gseq = rcu_state.barrier_sequence;
+	for_each_possible_cpu(cpu) {
+		rdp = per_cpu_ptr(&rcu_data, cpu);
+
+		WRITE_ONCE(rdp->barrier_seq_snap, gseq);
+	}
+
+	/* Other rcu_barrier() invocations can now safely proceed. */
+	mutex_unlock(&rcu_state.barrier_mutex);
+}
+EXPORT_SYMBOL_GPL(rcu_barrier);
+
+/*
+ * Propagate ->qsinitmask bits up the rcu_node tree to account for the
+ * first CPU in a given leaf rcu_node structure coming online.  The caller
+ * must hold the corresponding leaf rcu_node ->lock with interrupts
+ * disabled.
+ */
+static void rcu_init_new_rnp(struct rcu_node *rnp_leaf)
+{
+	long mask;
+	long oldmask;
+	struct rcu_node *rnp = rnp_leaf;
+
+	raw_lockdep_assert_held_rcu_node(rnp_leaf);
+	WARN_ON_ONCE(rnp->wait_blkd_tasks);
+	for (;;) {
+		mask = rnp->grpmask;
+		rnp = rnp->parent;
+		if (rnp == NULL)
+			return;
+		raw_spin_lock_rcu_node(rnp); /* Interrupts already disabled. */
+		oldmask = rnp->qsmaskinit;
+		rnp->qsmaskinit |= mask;
+		raw_spin_unlock_rcu_node(rnp); /* Interrupts remain disabled. */
+		if (oldmask)
+			return;
+	}
+}
+
+/*
+ * Do boot-time initialization of a CPU's per-CPU RCU data.
+ */
+static void __init
+rcu_boot_init_percpu_data(int cpu)
+{
+	struct context_tracking *ct = this_cpu_ptr(&context_tracking);
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+
+	/* Set up local state, ensuring consistent view of global state. */
+	rdp->grpmask = leaf_node_cpu_bit(rdp->mynode, cpu);
+	INIT_WORK(&rdp->strict_work, strict_work_handler);
+	WARN_ON_ONCE(ct->dynticks_nesting != 1);
+	WARN_ON_ONCE(rcu_dynticks_in_eqs(rcu_dynticks_snap(cpu)));
+	rdp->barrier_seq_snap = rcu_state.barrier_sequence;
+	rdp->rcu_ofl_gp_seq = rcu_state.gp_seq;
+	rdp->rcu_ofl_gp_flags = RCU_GP_CLEANED;
+	rdp->rcu_onl_gp_seq = rcu_state.gp_seq;
+	rdp->rcu_onl_gp_flags = RCU_GP_CLEANED;
+	rdp->last_sched_clock = jiffies;
+	rdp->cpu = cpu;
+	rcu_boot_init_nocb_percpu_data(rdp);
+}
+
+/*
+ * Invoked early in the CPU-online process, when pretty much all services
+ * are available.  The incoming CPU is not present.
+ *
+ * Initializes a CPU's per-CPU RCU data.  Note that only one online or
+ * offline event can be happening at a given time.  Note also that we can
+ * accept some slop in the rsp->gp_seq access due to the fact that this
+ * CPU cannot possibly have any non-offloaded RCU callbacks in flight yet.
+ * And any offloaded callbacks are being numbered elsewhere.
+ */
+int rcutree_prepare_cpu(unsigned int cpu)
+{
+	unsigned long flags;
+	struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu);
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+	struct rcu_node *rnp = rcu_get_root();
+
+	/* Set up local state, ensuring consistent view of global state. */
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	rdp->qlen_last_fqs_check = 0;
+	rdp->n_force_qs_snap = READ_ONCE(rcu_state.n_force_qs);
+	rdp->blimit = blimit;
+	ct->dynticks_nesting = 1;	/* CPU not up, no tearing. */
+	raw_spin_unlock_rcu_node(rnp);		/* irqs remain disabled. */
+
+	/*
+	 * Only non-NOCB CPUs that didn't have early-boot callbacks need to be
+	 * (re-)initialized.
+	 */
+	if (!rcu_segcblist_is_enabled(&rdp->cblist))
+		rcu_segcblist_init(&rdp->cblist);  /* Re-enable callbacks. */
+
+	/*
+	 * Add CPU to leaf rcu_node pending-online bitmask.  Any needed
+	 * propagation up the rcu_node tree will happen at the beginning
+	 * of the next grace period.
+	 */
+	rnp = rdp->mynode;
+	raw_spin_lock_rcu_node(rnp);		/* irqs already disabled. */
+	rdp->gp_seq = READ_ONCE(rnp->gp_seq);
+	rdp->gp_seq_needed = rdp->gp_seq;
+	rdp->cpu_no_qs.b.norm = true;
+	rdp->core_needs_qs = false;
+	rdp->rcu_iw_pending = false;
+	rdp->rcu_iw = IRQ_WORK_INIT_HARD(rcu_iw_handler);
+	rdp->rcu_iw_gp_seq = rdp->gp_seq - 1;
+	trace_rcu_grace_period(rcu_state.name, rdp->gp_seq, TPS("cpuonl"));
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	rcu_spawn_one_boost_kthread(rnp);
+	rcu_spawn_cpu_nocb_kthread(cpu);
+	WRITE_ONCE(rcu_state.n_online_cpus, rcu_state.n_online_cpus + 1);
+
+	return 0;
+}
+
+/*
+ * Update RCU priority boot kthread affinity for CPU-hotplug changes.
+ */
+static void rcutree_affinity_setting(unsigned int cpu, int outgoing)
+{
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+
+	rcu_boost_kthread_setaffinity(rdp->mynode, outgoing);
+}
+
+/*
+ * Has the specified (known valid) CPU ever been fully online?
+ */
+bool rcu_cpu_beenfullyonline(int cpu)
+{
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+
+	return smp_load_acquire(&rdp->beenonline);
+}
+
+/*
+ * Near the end of the CPU-online process.  Pretty much all services
+ * enabled, and the CPU is now very much alive.
+ */
+int rcutree_online_cpu(unsigned int cpu)
+{
+	unsigned long flags;
+	struct rcu_data *rdp;
+	struct rcu_node *rnp;
+
+	rdp = per_cpu_ptr(&rcu_data, cpu);
+	rnp = rdp->mynode;
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	rnp->ffmask |= rdp->grpmask;
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
+		return 0; /* Too early in boot for scheduler work. */
+	sync_sched_exp_online_cleanup(cpu);
+	rcutree_affinity_setting(cpu, -1);
+
+	// Stop-machine done, so allow nohz_full to disable tick.
+	tick_dep_clear(TICK_DEP_BIT_RCU);
+	return 0;
+}
+
+/*
+ * Near the beginning of the process.  The CPU is still very much alive
+ * with pretty much all services enabled.
+ */
+int rcutree_offline_cpu(unsigned int cpu)
+{
+	unsigned long flags;
+	struct rcu_data *rdp;
+	struct rcu_node *rnp;
+
+	rdp = per_cpu_ptr(&rcu_data, cpu);
+	rnp = rdp->mynode;
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	rnp->ffmask &= ~rdp->grpmask;
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+
+	rcutree_affinity_setting(cpu, cpu);
+
+	// nohz_full CPUs need the tick for stop-machine to work quickly
+	tick_dep_set(TICK_DEP_BIT_RCU);
+	return 0;
+}
+
+/*
+ * Mark the specified CPU as being online so that subsequent grace periods
+ * (both expedited and normal) will wait on it.  Note that this means that
+ * incoming CPUs are not allowed to use RCU read-side critical sections
+ * until this function is called.  Failing to observe this restriction
+ * will result in lockdep splats.
+ *
+ * Note that this function is special in that it is invoked directly
+ * from the incoming CPU rather than from the cpuhp_step mechanism.
+ * This is because this function must be invoked at a precise location.
+ * This incoming CPU must not have enabled interrupts yet.
+ */
+void rcu_cpu_starting(unsigned int cpu)
+{
+	unsigned long mask;
+	struct rcu_data *rdp;
+	struct rcu_node *rnp;
+	bool newcpu;
+
+	lockdep_assert_irqs_disabled();
+	rdp = per_cpu_ptr(&rcu_data, cpu);
+	if (rdp->cpu_started)
+		return;
+	rdp->cpu_started = true;
+
+	rnp = rdp->mynode;
+	mask = rdp->grpmask;
+	arch_spin_lock(&rcu_state.ofl_lock);
+	rcu_dynticks_eqs_online();
+	raw_spin_lock(&rcu_state.barrier_lock);
+	raw_spin_lock_rcu_node(rnp);
+	WRITE_ONCE(rnp->qsmaskinitnext, rnp->qsmaskinitnext | mask);
+	raw_spin_unlock(&rcu_state.barrier_lock);
+	newcpu = !(rnp->expmaskinitnext & mask);
+	rnp->expmaskinitnext |= mask;
+	/* Allow lockless access for expedited grace periods. */
+	smp_store_release(&rcu_state.ncpus, rcu_state.ncpus + newcpu); /* ^^^ */
+	ASSERT_EXCLUSIVE_WRITER(rcu_state.ncpus);
+	rcu_gpnum_ovf(rnp, rdp); /* Offline-induced counter wrap? */
+	rdp->rcu_onl_gp_seq = READ_ONCE(rcu_state.gp_seq);
+	rdp->rcu_onl_gp_flags = READ_ONCE(rcu_state.gp_flags);
+
+	/* An incoming CPU should never be blocking a grace period. */
+	if (WARN_ON_ONCE(rnp->qsmask & mask)) { /* RCU waiting on incoming CPU? */
+		/* rcu_report_qs_rnp() *really* wants some flags to restore */
+		unsigned long flags;
+
+		local_irq_save(flags);
+		rcu_disable_urgency_upon_qs(rdp);
+		/* Report QS -after- changing ->qsmaskinitnext! */
+		rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
+	} else {
+		raw_spin_unlock_rcu_node(rnp);
+	}
+	arch_spin_unlock(&rcu_state.ofl_lock);
+	smp_store_release(&rdp->beenonline, true);
+	smp_mb(); /* Ensure RCU read-side usage follows above initialization. */
+}
+
+/*
+ * The outgoing function has no further need of RCU, so remove it from
+ * the rcu_node tree's ->qsmaskinitnext bit masks.
+ *
+ * Note that this function is special in that it is invoked directly
+ * from the outgoing CPU rather than from the cpuhp_step mechanism.
+ * This is because this function must be invoked at a precise location.
+ */
+void rcu_report_dead(unsigned int cpu)
+{
+	unsigned long flags, seq_flags;
+	unsigned long mask;
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+	struct rcu_node *rnp = rdp->mynode;  /* Outgoing CPU's rdp & rnp. */
+
+	// Do any dangling deferred wakeups.
+	do_nocb_deferred_wakeup(rdp);
+
+	/* QS for any half-done expedited grace period. */
+	rcu_report_exp_rdp(rdp);
+	rcu_preempt_deferred_qs(current);
+
+	/* Remove outgoing CPU from mask in the leaf rcu_node structure. */
+	mask = rdp->grpmask;
+	local_irq_save(seq_flags);
+	arch_spin_lock(&rcu_state.ofl_lock);
+	raw_spin_lock_irqsave_rcu_node(rnp, flags); /* Enforce GP memory-order guarantee. */
+	rdp->rcu_ofl_gp_seq = READ_ONCE(rcu_state.gp_seq);
+	rdp->rcu_ofl_gp_flags = READ_ONCE(rcu_state.gp_flags);
+	if (rnp->qsmask & mask) { /* RCU waiting on outgoing CPU? */
+		/* Report quiescent state -before- changing ->qsmaskinitnext! */
+		rcu_disable_urgency_upon_qs(rdp);
+		rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	}
+	WRITE_ONCE(rnp->qsmaskinitnext, rnp->qsmaskinitnext & ~mask);
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	arch_spin_unlock(&rcu_state.ofl_lock);
+	local_irq_restore(seq_flags);
+
+	rdp->cpu_started = false;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * The outgoing CPU has just passed through the dying-idle state, and we
+ * are being invoked from the CPU that was IPIed to continue the offline
+ * operation.  Migrate the outgoing CPU's callbacks to the current CPU.
+ */
+void rcutree_migrate_callbacks(int cpu)
+{
+	unsigned long flags;
+	struct rcu_data *my_rdp;
+	struct rcu_node *my_rnp;
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+	bool needwake;
+
+	if (rcu_rdp_is_offloaded(rdp) ||
+	    rcu_segcblist_empty(&rdp->cblist))
+		return;  /* No callbacks to migrate. */
+
+	raw_spin_lock_irqsave(&rcu_state.barrier_lock, flags);
+	WARN_ON_ONCE(rcu_rdp_cpu_online(rdp));
+	rcu_barrier_entrain(rdp);
+	my_rdp = this_cpu_ptr(&rcu_data);
+	my_rnp = my_rdp->mynode;
+	rcu_nocb_lock(my_rdp); /* irqs already disabled. */
+	WARN_ON_ONCE(!rcu_nocb_flush_bypass(my_rdp, NULL, jiffies));
+	raw_spin_lock_rcu_node(my_rnp); /* irqs already disabled. */
+	/* Leverage recent GPs and set GP for new callbacks. */
+	needwake = rcu_advance_cbs(my_rnp, rdp) ||
+		   rcu_advance_cbs(my_rnp, my_rdp);
+	rcu_segcblist_merge(&my_rdp->cblist, &rdp->cblist);
+	raw_spin_unlock(&rcu_state.barrier_lock); /* irqs remain disabled. */
+	needwake = needwake || rcu_advance_cbs(my_rnp, my_rdp);
+	rcu_segcblist_disable(&rdp->cblist);
+	WARN_ON_ONCE(rcu_segcblist_empty(&my_rdp->cblist) != !rcu_segcblist_n_cbs(&my_rdp->cblist));
+	check_cb_ovld_locked(my_rdp, my_rnp);
+	if (rcu_rdp_is_offloaded(my_rdp)) {
+		raw_spin_unlock_rcu_node(my_rnp); /* irqs remain disabled. */
+		__call_rcu_nocb_wake(my_rdp, true, flags);
+	} else {
+		rcu_nocb_unlock(my_rdp); /* irqs remain disabled. */
+		raw_spin_unlock_irqrestore_rcu_node(my_rnp, flags);
+	}
+	if (needwake)
+		rcu_gp_kthread_wake();
+	lockdep_assert_irqs_enabled();
+	WARN_ONCE(rcu_segcblist_n_cbs(&rdp->cblist) != 0 ||
+		  !rcu_segcblist_empty(&rdp->cblist),
+		  "rcu_cleanup_dead_cpu: Callbacks on offline CPU %d: qlen=%lu, 1stCB=%p\n",
+		  cpu, rcu_segcblist_n_cbs(&rdp->cblist),
+		  rcu_segcblist_first_cb(&rdp->cblist));
+}
+#endif
+
+/*
+ * On non-huge systems, use expedited RCU grace periods to make suspend
+ * and hibernation run faster.
+ */
+static int rcu_pm_notify(struct notifier_block *self,
+			 unsigned long action, void *hcpu)
+{
+	switch (action) {
+	case PM_HIBERNATION_PREPARE:
+	case PM_SUSPEND_PREPARE:
+		rcu_expedite_gp();
+		break;
+	case PM_POST_HIBERNATION:
+	case PM_POST_SUSPEND:
+		rcu_unexpedite_gp();
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+#ifdef CONFIG_RCU_EXP_KTHREAD
+struct kthread_worker *rcu_exp_gp_kworker;
+struct kthread_worker *rcu_exp_par_gp_kworker;
+
+static void __init rcu_start_exp_gp_kworkers(void)
+{
+	const char *par_gp_kworker_name = "rcu_exp_par_gp_kthread_worker";
+	const char *gp_kworker_name = "rcu_exp_gp_kthread_worker";
+	struct sched_param param = { .sched_priority = kthread_prio };
+
+	rcu_exp_gp_kworker = kthread_create_worker(0, gp_kworker_name);
+	if (IS_ERR_OR_NULL(rcu_exp_gp_kworker)) {
+		pr_err("Failed to create %s!\n", gp_kworker_name);
+		return;
+	}
+
+	rcu_exp_par_gp_kworker = kthread_create_worker(0, par_gp_kworker_name);
+	if (IS_ERR_OR_NULL(rcu_exp_par_gp_kworker)) {
+		pr_err("Failed to create %s!\n", par_gp_kworker_name);
+		kthread_destroy_worker(rcu_exp_gp_kworker);
+		return;
+	}
+
+	sched_setscheduler_nocheck(rcu_exp_gp_kworker->task, SCHED_FIFO, &param);
+	sched_setscheduler_nocheck(rcu_exp_par_gp_kworker->task, SCHED_FIFO,
+				   &param);
+}
+
+static inline void rcu_alloc_par_gp_wq(void)
+{
+}
+#else /* !CONFIG_RCU_EXP_KTHREAD */
+struct workqueue_struct *rcu_par_gp_wq;
+
+static void __init rcu_start_exp_gp_kworkers(void)
+{
+}
+
+static inline void rcu_alloc_par_gp_wq(void)
+{
+	rcu_par_gp_wq = alloc_workqueue("rcu_par_gp", WQ_MEM_RECLAIM, 0);
+	WARN_ON(!rcu_par_gp_wq);
+}
+#endif /* CONFIG_RCU_EXP_KTHREAD */
+
+/*
+ * Spawn the kthreads that handle RCU's grace periods.
+ */
+static int __init rcu_spawn_gp_kthread(void)
+{
+	unsigned long flags;
+	struct rcu_node *rnp;
+	struct sched_param sp;
+	struct task_struct *t;
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
+
+	rcu_scheduler_fully_active = 1;
+	t = kthread_create(rcu_gp_kthread, NULL, "%s", rcu_state.name);
+	if (WARN_ONCE(IS_ERR(t), "%s: Could not start grace-period kthread, OOM is now expected behavior\n", __func__))
+		return 0;
+	if (kthread_prio) {
+		sp.sched_priority = kthread_prio;
+		sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
+	}
+	rnp = rcu_get_root();
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	WRITE_ONCE(rcu_state.gp_activity, jiffies);
+	WRITE_ONCE(rcu_state.gp_req_activity, jiffies);
+	// Reset .gp_activity and .gp_req_activity before setting .gp_kthread.
+	smp_store_release(&rcu_state.gp_kthread, t);  /* ^^^ */
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	wake_up_process(t);
+	/* This is a pre-SMP initcall, we expect a single CPU */
+	WARN_ON(num_online_cpus() > 1);
+	/*
+	 * Those kthreads couldn't be created on rcu_init() -> rcutree_prepare_cpu()
+	 * due to rcu_scheduler_fully_active.
+	 */
+	rcu_spawn_cpu_nocb_kthread(smp_processor_id());
+	rcu_spawn_one_boost_kthread(rdp->mynode);
+	rcu_spawn_core_kthreads();
+	/* Create kthread worker for expedited GPs */
+	rcu_start_exp_gp_kworkers();
+	return 0;
+}
+early_initcall(rcu_spawn_gp_kthread);
+
+/*
+ * This function is invoked towards the end of the scheduler's
+ * initialization process.  Before this is called, the idle task might
+ * contain synchronous grace-period primitives (during which time, this idle
+ * task is booting the system, and such primitives are no-ops).  After this
+ * function is called, any synchronous grace-period primitives are run as
+ * expedited, with the requesting task driving the grace period forward.
+ * A later core_initcall() rcu_set_runtime_mode() will switch to full
+ * runtime RCU functionality.
+ */
+void rcu_scheduler_starting(void)
+{
+	unsigned long flags;
+	struct rcu_node *rnp;
+
+	WARN_ON(num_online_cpus() != 1);
+	WARN_ON(nr_context_switches() > 0);
+	rcu_test_sync_prims();
+
+	// Fix up the ->gp_seq counters.
+	local_irq_save(flags);
+	rcu_for_each_node_breadth_first(rnp)
+		rnp->gp_seq_needed = rnp->gp_seq = rcu_state.gp_seq;
+	local_irq_restore(flags);
+
+	// Switch out of early boot mode.
+	rcu_scheduler_active = RCU_SCHEDULER_INIT;
+	rcu_test_sync_prims();
+}
+
+/*
+ * Helper function for rcu_init() that initializes the rcu_state structure.
+ */
+static void __init rcu_init_one(void)
+{
+	static const char * const buf[] = RCU_NODE_NAME_INIT;
+	static const char * const fqs[] = RCU_FQS_NAME_INIT;
+	static struct lock_class_key rcu_node_class[RCU_NUM_LVLS];
+	static struct lock_class_key rcu_fqs_class[RCU_NUM_LVLS];
+
+	int levelspread[RCU_NUM_LVLS];		/* kids/node in each level. */
+	int cpustride = 1;
+	int i;
+	int j;
+	struct rcu_node *rnp;
+
+	BUILD_BUG_ON(RCU_NUM_LVLS > ARRAY_SIZE(buf));  /* Fix buf[] init! */
+
+	/* Silence gcc 4.8 false positive about array index out of range. */
+	if (rcu_num_lvls <= 0 || rcu_num_lvls > RCU_NUM_LVLS)
+		panic("rcu_init_one: rcu_num_lvls out of range");
+
+	/* Initialize the level-tracking arrays. */
+
+	for (i = 1; i < rcu_num_lvls; i++)
+		rcu_state.level[i] =
+			rcu_state.level[i - 1] + num_rcu_lvl[i - 1];
+	rcu_init_levelspread(levelspread, num_rcu_lvl);
+
+	/* Initialize the elements themselves, starting from the leaves. */
+
+	for (i = rcu_num_lvls - 1; i >= 0; i--) {
+		cpustride *= levelspread[i];
+		rnp = rcu_state.level[i];
+		for (j = 0; j < num_rcu_lvl[i]; j++, rnp++) {
+			raw_spin_lock_init(&ACCESS_PRIVATE(rnp, lock));
+			lockdep_set_class_and_name(&ACCESS_PRIVATE(rnp, lock),
+						   &rcu_node_class[i], buf[i]);
+			raw_spin_lock_init(&rnp->fqslock);
+			lockdep_set_class_and_name(&rnp->fqslock,
+						   &rcu_fqs_class[i], fqs[i]);
+			rnp->gp_seq = rcu_state.gp_seq;
+			rnp->gp_seq_needed = rcu_state.gp_seq;
+			rnp->completedqs = rcu_state.gp_seq;
+			rnp->qsmask = 0;
+			rnp->qsmaskinit = 0;
+			rnp->grplo = j * cpustride;
+			rnp->grphi = (j + 1) * cpustride - 1;
+			if (rnp->grphi >= nr_cpu_ids)
+				rnp->grphi = nr_cpu_ids - 1;
+			if (i == 0) {
+				rnp->grpnum = 0;
+				rnp->grpmask = 0;
+				rnp->parent = NULL;
+			} else {
+				rnp->grpnum = j % levelspread[i - 1];
+				rnp->grpmask = BIT(rnp->grpnum);
+				rnp->parent = rcu_state.level[i - 1] +
+					      j / levelspread[i - 1];
+			}
+			rnp->level = i;
+			INIT_LIST_HEAD(&rnp->blkd_tasks);
+			rcu_init_one_nocb(rnp);
+			init_waitqueue_head(&rnp->exp_wq[0]);
+			init_waitqueue_head(&rnp->exp_wq[1]);
+			init_waitqueue_head(&rnp->exp_wq[2]);
+			init_waitqueue_head(&rnp->exp_wq[3]);
+			spin_lock_init(&rnp->exp_lock);
+			mutex_init(&rnp->boost_kthread_mutex);
+			raw_spin_lock_init(&rnp->exp_poll_lock);
+			rnp->exp_seq_poll_rq = RCU_GET_STATE_COMPLETED;
+			INIT_WORK(&rnp->exp_poll_wq, sync_rcu_do_polled_gp);
+		}
+	}
+
+	init_swait_queue_head(&rcu_state.gp_wq);
+	init_swait_queue_head(&rcu_state.expedited_wq);
+	rnp = rcu_first_leaf_node();
+	for_each_possible_cpu(i) {
+		while (i > rnp->grphi)
+			rnp++;
+		per_cpu_ptr(&rcu_data, i)->mynode = rnp;
+		rcu_boot_init_percpu_data(i);
+	}
+}
+
+/*
+ * Force priority from the kernel command-line into range.
+ */
+static void __init sanitize_kthread_prio(void)
+{
+	int kthread_prio_in = kthread_prio;
+
+	if (IS_ENABLED(CONFIG_RCU_BOOST) && kthread_prio < 2
+	    && IS_BUILTIN(CONFIG_RCU_TORTURE_TEST))
+		kthread_prio = 2;
+	else if (IS_ENABLED(CONFIG_RCU_BOOST) && kthread_prio < 1)
+		kthread_prio = 1;
+	else if (kthread_prio < 0)
+		kthread_prio = 0;
+	else if (kthread_prio > 99)
+		kthread_prio = 99;
+
+	if (kthread_prio != kthread_prio_in)
+		pr_alert("%s: Limited prio to %d from %d\n",
+			 __func__, kthread_prio, kthread_prio_in);
+}
+
+/*
+ * Compute the rcu_node tree geometry from kernel parameters.  This cannot
+ * replace the definitions in tree.h because those are needed to size
+ * the ->node array in the rcu_state structure.
+ */
+void rcu_init_geometry(void)
+{
+	ulong d;
+	int i;
+	static unsigned long old_nr_cpu_ids;
+	int rcu_capacity[RCU_NUM_LVLS];
+	static bool initialized;
+
+	if (initialized) {
+		/*
+		 * Warn if setup_nr_cpu_ids() had not yet been invoked,
+		 * unless nr_cpus_ids == NR_CPUS, in which case who cares?
+		 */
+		WARN_ON_ONCE(old_nr_cpu_ids != nr_cpu_ids);
+		return;
+	}
+
+	old_nr_cpu_ids = nr_cpu_ids;
+	initialized = true;
+
+	/*
+	 * Initialize any unspecified boot parameters.
+	 * The default values of jiffies_till_first_fqs and
+	 * jiffies_till_next_fqs are set to the RCU_JIFFIES_TILL_FORCE_QS
+	 * value, which is a function of HZ, then adding one for each
+	 * RCU_JIFFIES_FQS_DIV CPUs that might be on the system.
+	 */
+	d = RCU_JIFFIES_TILL_FORCE_QS + nr_cpu_ids / RCU_JIFFIES_FQS_DIV;
+	if (jiffies_till_first_fqs == ULONG_MAX)
+		jiffies_till_first_fqs = d;
+	if (jiffies_till_next_fqs == ULONG_MAX)
+		jiffies_till_next_fqs = d;
+	adjust_jiffies_till_sched_qs();
+
+	/* If the compile-time values are accurate, just leave. */
+	if (rcu_fanout_leaf == RCU_FANOUT_LEAF &&
+	    nr_cpu_ids == NR_CPUS)
+		return;
+	pr_info("Adjusting geometry for rcu_fanout_leaf=%d, nr_cpu_ids=%u\n",
+		rcu_fanout_leaf, nr_cpu_ids);
+
+	/*
+	 * The boot-time rcu_fanout_leaf parameter must be at least two
+	 * and cannot exceed the number of bits in the rcu_node masks.
+	 * Complain and fall back to the compile-time values if this
+	 * limit is exceeded.
+	 */
+	if (rcu_fanout_leaf < 2 ||
+	    rcu_fanout_leaf > sizeof(unsigned long) * 8) {
+		rcu_fanout_leaf = RCU_FANOUT_LEAF;
+		WARN_ON(1);
+		return;
+	}
+
+	/*
+	 * Compute number of nodes that can be handled an rcu_node tree
+	 * with the given number of levels.
+	 */
+	rcu_capacity[0] = rcu_fanout_leaf;
+	for (i = 1; i < RCU_NUM_LVLS; i++)
+		rcu_capacity[i] = rcu_capacity[i - 1] * RCU_FANOUT;
+
+	/*
+	 * The tree must be able to accommodate the configured number of CPUs.
+	 * If this limit is exceeded, fall back to the compile-time values.
+	 */
+	if (nr_cpu_ids > rcu_capacity[RCU_NUM_LVLS - 1]) {
+		rcu_fanout_leaf = RCU_FANOUT_LEAF;
+		WARN_ON(1);
+		return;
+	}
+
+	/* Calculate the number of levels in the tree. */
+	for (i = 0; nr_cpu_ids > rcu_capacity[i]; i++) {
+	}
+	rcu_num_lvls = i + 1;
+
+	/* Calculate the number of rcu_nodes at each level of the tree. */
+	for (i = 0; i < rcu_num_lvls; i++) {
+		int cap = rcu_capacity[(rcu_num_lvls - 1) - i];
+		num_rcu_lvl[i] = DIV_ROUND_UP(nr_cpu_ids, cap);
+	}
+
+	/* Calculate the total number of rcu_node structures. */
+	rcu_num_nodes = 0;
+	for (i = 0; i < rcu_num_lvls; i++)
+		rcu_num_nodes += num_rcu_lvl[i];
+}
+
+/*
+ * Dump out the structure of the rcu_node combining tree associated
+ * with the rcu_state structure.
+ */
+static void __init rcu_dump_rcu_node_tree(void)
+{
+	int level = 0;
+	struct rcu_node *rnp;
+
+	pr_info("rcu_node tree layout dump\n");
+	pr_info(" ");
+	rcu_for_each_node_breadth_first(rnp) {
+		if (rnp->level != level) {
+			pr_cont("\n");
+			pr_info(" ");
+			level = rnp->level;
+		}
+		pr_cont("%d:%d ^%d  ", rnp->grplo, rnp->grphi, rnp->grpnum);
+	}
+	pr_cont("\n");
+}
+
+struct workqueue_struct *rcu_gp_wq;
+
+static void __init kfree_rcu_batch_init(void)
+{
+	int cpu;
+	int i;
+
+	/* Clamp it to [0:100] seconds interval. */
+	if (rcu_delay_page_cache_fill_msec < 0 ||
+		rcu_delay_page_cache_fill_msec > 100 * MSEC_PER_SEC) {
+
+		rcu_delay_page_cache_fill_msec =
+			clamp(rcu_delay_page_cache_fill_msec, 0,
+				(int) (100 * MSEC_PER_SEC));
+
+		pr_info("Adjusting rcutree.rcu_delay_page_cache_fill_msec to %d ms.\n",
+			rcu_delay_page_cache_fill_msec);
+	}
+
+	for_each_possible_cpu(cpu) {
+		struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu);
+
+		for (i = 0; i < KFREE_N_BATCHES; i++) {
+			INIT_RCU_WORK(&krcp->krw_arr[i].rcu_work, kfree_rcu_work);
+			krcp->krw_arr[i].krcp = krcp;
+		}
+
+		INIT_DELAYED_WORK(&krcp->monitor_work, kfree_rcu_monitor);
+		INIT_DELAYED_WORK(&krcp->page_cache_work, fill_page_cache_func);
+		krcp->initialized = true;
+	}
+	if (register_shrinker(&kfree_rcu_shrinker, "rcu-kfree"))
+		pr_err("Failed to register kfree_rcu() shrinker!\n");
+}
+
+void __init rcu_init(void)
+{
+	int cpu = smp_processor_id();
+
+	rcu_early_boot_tests();
+
+	kfree_rcu_batch_init();
+	rcu_bootup_announce();
+	sanitize_kthread_prio();
+	rcu_init_geometry();
+	rcu_init_one();
+	if (dump_tree)
+		rcu_dump_rcu_node_tree();
+	if (use_softirq)
+		open_softirq(RCU_SOFTIRQ, rcu_core_si);
+
+	/*
+	 * We don't need protection against CPU-hotplug here because
+	 * this is called early in boot, before either interrupts
+	 * or the scheduler are operational.
+	 */
+	pm_notifier(rcu_pm_notify, 0);
+	WARN_ON(num_online_cpus() > 1); // Only one CPU this early in boot.
+	rcutree_prepare_cpu(cpu);
+	rcu_cpu_starting(cpu);
+	rcutree_online_cpu(cpu);
+
+	/* Create workqueue for Tree SRCU and for expedited GPs. */
+	rcu_gp_wq = alloc_workqueue("rcu_gp", WQ_MEM_RECLAIM, 0);
+	WARN_ON(!rcu_gp_wq);
+	rcu_alloc_par_gp_wq();
+
+	/* Fill in default value for rcutree.qovld boot parameter. */
+	/* -After- the rcu_node ->lock fields are initialized! */
+	if (qovld < 0)
+		qovld_calc = DEFAULT_RCU_QOVLD_MULT * qhimark;
+	else
+		qovld_calc = qovld;
+
+	// Kick-start any polled grace periods that started early.
+	if (!(per_cpu_ptr(&rcu_data, cpu)->mynode->exp_seq_poll_rq & 0x1))
+		(void)start_poll_synchronize_rcu_expedited();
+}
+
+#include "tree_stall.h"
+#include "tree_exp.h"
+#include "tree_nocb.h"
+#include "tree_plugin.h"
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
new file mode 100644
index 000000000..7b702220d
--- /dev/null
+++ b/kernel/rcu/tree.h
@@ -0,0 +1,490 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Read-Copy Update mechanism for mutual exclusion (tree-based version)
+ * Internal non-public definitions.
+ *
+ * Copyright IBM Corporation, 2008
+ *
+ * Author: Ingo Molnar <mingo@elte.hu>
+ *	   Paul E. McKenney <paulmck@linux.ibm.com>
+ */
+
+#include <linux/cache.h>
+#include <linux/kthread.h>
+#include <linux/spinlock.h>
+#include <linux/rtmutex.h>
+#include <linux/threads.h>
+#include <linux/cpumask.h>
+#include <linux/seqlock.h>
+#include <linux/swait.h>
+#include <linux/rcu_node_tree.h>
+
+#include "rcu_segcblist.h"
+
+/* Communicate arguments to a workqueue handler. */
+struct rcu_exp_work {
+	unsigned long rew_s;
+#ifdef CONFIG_RCU_EXP_KTHREAD
+	struct kthread_work rew_work;
+#else
+	struct work_struct rew_work;
+#endif /* CONFIG_RCU_EXP_KTHREAD */
+};
+
+/* RCU's kthread states for tracing. */
+#define RCU_KTHREAD_STOPPED  0
+#define RCU_KTHREAD_RUNNING  1
+#define RCU_KTHREAD_WAITING  2
+#define RCU_KTHREAD_OFFCPU   3
+#define RCU_KTHREAD_YIELDING 4
+#define RCU_KTHREAD_MAX      4
+
+/*
+ * Definition for node within the RCU grace-period-detection hierarchy.
+ */
+struct rcu_node {
+	raw_spinlock_t __private lock;	/* Root rcu_node's lock protects */
+					/*  some rcu_state fields as well as */
+					/*  following. */
+	unsigned long gp_seq;	/* Track rsp->gp_seq. */
+	unsigned long gp_seq_needed; /* Track furthest future GP request. */
+	unsigned long completedqs; /* All QSes done for this node. */
+	unsigned long qsmask;	/* CPUs or groups that need to switch in */
+				/*  order for current grace period to proceed.*/
+				/*  In leaf rcu_node, each bit corresponds to */
+				/*  an rcu_data structure, otherwise, each */
+				/*  bit corresponds to a child rcu_node */
+				/*  structure. */
+	unsigned long rcu_gp_init_mask;	/* Mask of offline CPUs at GP init. */
+	unsigned long qsmaskinit;
+				/* Per-GP initial value for qsmask. */
+				/*  Initialized from ->qsmaskinitnext at the */
+				/*  beginning of each grace period. */
+	unsigned long qsmaskinitnext;
+	unsigned long expmask;	/* CPUs or groups that need to check in */
+				/*  to allow the current expedited GP */
+				/*  to complete. */
+	unsigned long expmaskinit;
+				/* Per-GP initial values for expmask. */
+				/*  Initialized from ->expmaskinitnext at the */
+				/*  beginning of each expedited GP. */
+	unsigned long expmaskinitnext;
+				/* Online CPUs for next expedited GP. */
+				/*  Any CPU that has ever been online will */
+				/*  have its bit set. */
+	unsigned long cbovldmask;
+				/* CPUs experiencing callback overload. */
+	unsigned long ffmask;	/* Fully functional CPUs. */
+	unsigned long grpmask;	/* Mask to apply to parent qsmask. */
+				/*  Only one bit will be set in this mask. */
+	int	grplo;		/* lowest-numbered CPU here. */
+	int	grphi;		/* highest-numbered CPU here. */
+	u8	grpnum;		/* group number for next level up. */
+	u8	level;		/* root is at level 0. */
+	bool	wait_blkd_tasks;/* Necessary to wait for blocked tasks to */
+				/*  exit RCU read-side critical sections */
+				/*  before propagating offline up the */
+				/*  rcu_node tree? */
+	struct rcu_node *parent;
+	struct list_head blkd_tasks;
+				/* Tasks blocked in RCU read-side critical */
+				/*  section.  Tasks are placed at the head */
+				/*  of this list and age towards the tail. */
+	struct list_head *gp_tasks;
+				/* Pointer to the first task blocking the */
+				/*  current grace period, or NULL if there */
+				/*  is no such task. */
+	struct list_head *exp_tasks;
+				/* Pointer to the first task blocking the */
+				/*  current expedited grace period, or NULL */
+				/*  if there is no such task.  If there */
+				/*  is no current expedited grace period, */
+				/*  then there can cannot be any such task. */
+	struct list_head *boost_tasks;
+				/* Pointer to first task that needs to be */
+				/*  priority boosted, or NULL if no priority */
+				/*  boosting is needed for this rcu_node */
+				/*  structure.  If there are no tasks */
+				/*  queued on this rcu_node structure that */
+				/*  are blocking the current grace period, */
+				/*  there can be no such task. */
+	struct rt_mutex boost_mtx;
+				/* Used only for the priority-boosting */
+				/*  side effect, not as a lock. */
+	unsigned long boost_time;
+				/* When to start boosting (jiffies). */
+	struct mutex boost_kthread_mutex;
+				/* Exclusion for thread spawning and affinity */
+				/*  manipulation. */
+	struct task_struct *boost_kthread_task;
+				/* kthread that takes care of priority */
+				/*  boosting for this rcu_node structure. */
+	unsigned int boost_kthread_status;
+				/* State of boost_kthread_task for tracing. */
+	unsigned long n_boosts;	/* Number of boosts for this rcu_node structure. */
+#ifdef CONFIG_RCU_NOCB_CPU
+	struct swait_queue_head nocb_gp_wq[2];
+				/* Place for rcu_nocb_kthread() to wait GP. */
+#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
+	raw_spinlock_t fqslock ____cacheline_internodealigned_in_smp;
+
+	spinlock_t exp_lock ____cacheline_internodealigned_in_smp;
+	unsigned long exp_seq_rq;
+	wait_queue_head_t exp_wq[4];
+	struct rcu_exp_work rew;
+	bool exp_need_flush;	/* Need to flush workitem? */
+	raw_spinlock_t exp_poll_lock;
+				/* Lock and data for polled expedited grace periods. */
+	unsigned long exp_seq_poll_rq;
+	struct work_struct exp_poll_wq;
+} ____cacheline_internodealigned_in_smp;
+
+/*
+ * Bitmasks in an rcu_node cover the interval [grplo, grphi] of CPU IDs, and
+ * are indexed relative to this interval rather than the global CPU ID space.
+ * This generates the bit for a CPU in node-local masks.
+ */
+#define leaf_node_cpu_bit(rnp, cpu) (BIT((cpu) - (rnp)->grplo))
+
+/*
+ * Union to allow "aggregate OR" operation on the need for a quiescent
+ * state by the normal and expedited grace periods.
+ */
+union rcu_noqs {
+	struct {
+		u8 norm;
+		u8 exp;
+	} b; /* Bits. */
+	u16 s; /* Set of bits, aggregate OR here. */
+};
+
+/* Per-CPU data for read-copy update. */
+struct rcu_data {
+	/* 1) quiescent-state and grace-period handling : */
+	unsigned long	gp_seq;		/* Track rsp->gp_seq counter. */
+	unsigned long	gp_seq_needed;	/* Track furthest future GP request. */
+	union rcu_noqs	cpu_no_qs;	/* No QSes yet for this CPU. */
+	bool		core_needs_qs;	/* Core waits for quiescent state. */
+	bool		beenonline;	/* CPU online at least once. */
+	bool		gpwrap;		/* Possible ->gp_seq wrap. */
+	bool		cpu_started;	/* RCU watching this onlining CPU. */
+	struct rcu_node *mynode;	/* This CPU's leaf of hierarchy */
+	unsigned long grpmask;		/* Mask to apply to leaf qsmask. */
+	unsigned long	ticks_this_gp;	/* The number of scheduling-clock */
+					/*  ticks this CPU has handled */
+					/*  during and after the last grace */
+					/* period it is aware of. */
+	struct irq_work defer_qs_iw;	/* Obtain later scheduler attention. */
+	bool defer_qs_iw_pending;	/* Scheduler attention pending? */
+	struct work_struct strict_work;	/* Schedule readers for strict GPs. */
+
+	/* 2) batch handling */
+	struct rcu_segcblist cblist;	/* Segmented callback list, with */
+					/* different callbacks waiting for */
+					/* different grace periods. */
+	long		qlen_last_fqs_check;
+					/* qlen at last check for QS forcing */
+	unsigned long	n_cbs_invoked;	/* # callbacks invoked since boot. */
+	unsigned long	n_force_qs_snap;
+					/* did other CPU force QS recently? */
+	long		blimit;		/* Upper limit on a processed batch */
+
+	/* 3) dynticks interface. */
+	int dynticks_snap;		/* Per-GP tracking for dynticks. */
+	bool rcu_need_heavy_qs;		/* GP old, so heavy quiescent state! */
+	bool rcu_urgent_qs;		/* GP old need light quiescent state. */
+	bool rcu_forced_tick;		/* Forced tick to provide QS. */
+	bool rcu_forced_tick_exp;	/*   ... provide QS to expedited GP. */
+
+	/* 4) rcu_barrier(), OOM callbacks, and expediting. */
+	unsigned long barrier_seq_snap;	/* Snap of rcu_state.barrier_sequence. */
+	struct rcu_head barrier_head;
+	int exp_dynticks_snap;		/* Double-check need for IPI. */
+
+	/* 5) Callback offloading. */
+#ifdef CONFIG_RCU_NOCB_CPU
+	struct swait_queue_head nocb_cb_wq; /* For nocb kthreads to sleep on. */
+	struct swait_queue_head nocb_state_wq; /* For offloading state changes */
+	struct task_struct *nocb_gp_kthread;
+	raw_spinlock_t nocb_lock;	/* Guard following pair of fields. */
+	atomic_t nocb_lock_contended;	/* Contention experienced. */
+	int nocb_defer_wakeup;		/* Defer wakeup of nocb_kthread. */
+	struct timer_list nocb_timer;	/* Enforce finite deferral. */
+	unsigned long nocb_gp_adv_time;	/* Last call_rcu() CB adv (jiffies). */
+	struct mutex nocb_gp_kthread_mutex; /* Exclusion for nocb gp kthread */
+					    /* spawning */
+
+	/* The following fields are used by call_rcu, hence own cacheline. */
+	raw_spinlock_t nocb_bypass_lock ____cacheline_internodealigned_in_smp;
+	struct rcu_cblist nocb_bypass;	/* Lock-contention-bypass CB list. */
+	unsigned long nocb_bypass_first; /* Time (jiffies) of first enqueue. */
+	unsigned long nocb_nobypass_last; /* Last ->cblist enqueue (jiffies). */
+	int nocb_nobypass_count;	/* # ->cblist enqueues at ^^^ time. */
+
+	/* The following fields are used by GP kthread, hence own cacheline. */
+	raw_spinlock_t nocb_gp_lock ____cacheline_internodealigned_in_smp;
+	u8 nocb_gp_sleep;		/* Is the nocb GP thread asleep? */
+	u8 nocb_gp_bypass;		/* Found a bypass on last scan? */
+	u8 nocb_gp_gp;			/* GP to wait for on last scan? */
+	unsigned long nocb_gp_seq;	/*  If so, ->gp_seq to wait for. */
+	unsigned long nocb_gp_loops;	/* # passes through wait code. */
+	struct swait_queue_head nocb_gp_wq; /* For nocb kthreads to sleep on. */
+	bool nocb_cb_sleep;		/* Is the nocb CB thread asleep? */
+	struct task_struct *nocb_cb_kthread;
+	struct list_head nocb_head_rdp; /*
+					 * Head of rcu_data list in wakeup chain,
+					 * if rdp_gp.
+					 */
+	struct list_head nocb_entry_rdp; /* rcu_data node in wakeup chain. */
+	struct rcu_data *nocb_toggling_rdp; /* rdp queued for (de-)offloading */
+
+	/* The following fields are used by CB kthread, hence new cacheline. */
+	struct rcu_data *nocb_gp_rdp ____cacheline_internodealigned_in_smp;
+					/* GP rdp takes GP-end wakeups. */
+#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
+
+	/* 6) RCU priority boosting. */
+	struct task_struct *rcu_cpu_kthread_task;
+					/* rcuc per-CPU kthread or NULL. */
+	unsigned int rcu_cpu_kthread_status;
+	char rcu_cpu_has_work;
+	unsigned long rcuc_activity;
+
+	/* 7) Diagnostic data, including RCU CPU stall warnings. */
+	unsigned int softirq_snap;	/* Snapshot of softirq activity. */
+	/* ->rcu_iw* fields protected by leaf rcu_node ->lock. */
+	struct irq_work rcu_iw;		/* Check for non-irq activity. */
+	bool rcu_iw_pending;		/* Is ->rcu_iw pending? */
+	unsigned long rcu_iw_gp_seq;	/* ->gp_seq associated with ->rcu_iw. */
+	unsigned long rcu_ofl_gp_seq;	/* ->gp_seq at last offline. */
+	short rcu_ofl_gp_flags;		/* ->gp_flags at last offline. */
+	unsigned long rcu_onl_gp_seq;	/* ->gp_seq at last online. */
+	short rcu_onl_gp_flags;		/* ->gp_flags at last online. */
+	unsigned long last_fqs_resched;	/* Time of last rcu_resched(). */
+	unsigned long last_sched_clock;	/* Jiffies of last rcu_sched_clock_irq(). */
+
+	int cpu;
+};
+
+/* Values for nocb_defer_wakeup field in struct rcu_data. */
+#define RCU_NOCB_WAKE_NOT	0
+#define RCU_NOCB_WAKE_BYPASS	1
+#define RCU_NOCB_WAKE		2
+#define RCU_NOCB_WAKE_FORCE	3
+
+#define RCU_JIFFIES_TILL_FORCE_QS (1 + (HZ > 250) + (HZ > 500))
+					/* For jiffies_till_first_fqs and */
+					/*  and jiffies_till_next_fqs. */
+
+#define RCU_JIFFIES_FQS_DIV	256	/* Very large systems need more */
+					/*  delay between bouts of */
+					/*  quiescent-state forcing. */
+
+#define RCU_STALL_RAT_DELAY	2	/* Allow other CPUs time to take */
+					/*  at least one scheduling clock */
+					/*  irq before ratting on them. */
+
+#define rcu_wait(cond)							\
+do {									\
+	for (;;) {							\
+		set_current_state(TASK_INTERRUPTIBLE);			\
+		if (cond)						\
+			break;						\
+		schedule();						\
+	}								\
+	__set_current_state(TASK_RUNNING);				\
+} while (0)
+
+/*
+ * RCU global state, including node hierarchy.  This hierarchy is
+ * represented in "heap" form in a dense array.  The root (first level)
+ * of the hierarchy is in ->node[0] (referenced by ->level[0]), the second
+ * level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]),
+ * and the third level in ->node[m+1] and following (->node[m+1] referenced
+ * by ->level[2]).  The number of levels is determined by the number of
+ * CPUs and by CONFIG_RCU_FANOUT.  Small systems will have a "hierarchy"
+ * consisting of a single rcu_node.
+ */
+struct rcu_state {
+	struct rcu_node node[NUM_RCU_NODES];	/* Hierarchy. */
+	struct rcu_node *level[RCU_NUM_LVLS + 1];
+						/* Hierarchy levels (+1 to */
+						/*  shut bogus gcc warning) */
+	int ncpus;				/* # CPUs seen so far. */
+	int n_online_cpus;			/* # CPUs online for RCU. */
+
+	/* The following fields are guarded by the root rcu_node's lock. */
+
+	unsigned long gp_seq ____cacheline_internodealigned_in_smp;
+						/* Grace-period sequence #. */
+	unsigned long gp_max;			/* Maximum GP duration in */
+						/*  jiffies. */
+	struct task_struct *gp_kthread;		/* Task for grace periods. */
+	struct swait_queue_head gp_wq;		/* Where GP task waits. */
+	short gp_flags;				/* Commands for GP task. */
+	short gp_state;				/* GP kthread sleep state. */
+	unsigned long gp_wake_time;		/* Last GP kthread wake. */
+	unsigned long gp_wake_seq;		/* ->gp_seq at ^^^. */
+	unsigned long gp_seq_polled;		/* GP seq for polled API. */
+	unsigned long gp_seq_polled_snap;	/* ->gp_seq_polled at normal GP start. */
+	unsigned long gp_seq_polled_exp_snap;	/* ->gp_seq_polled at expedited GP start. */
+
+	/* End of fields guarded by root rcu_node's lock. */
+
+	struct mutex barrier_mutex;		/* Guards barrier fields. */
+	atomic_t barrier_cpu_count;		/* # CPUs waiting on. */
+	struct completion barrier_completion;	/* Wake at barrier end. */
+	unsigned long barrier_sequence;		/* ++ at start and end of */
+						/*  rcu_barrier(). */
+	/* End of fields guarded by barrier_mutex. */
+
+	raw_spinlock_t barrier_lock;		/* Protects ->barrier_seq_snap. */
+
+	struct mutex exp_mutex;			/* Serialize expedited GP. */
+	struct mutex exp_wake_mutex;		/* Serialize wakeup. */
+	unsigned long expedited_sequence;	/* Take a ticket. */
+	atomic_t expedited_need_qs;		/* # CPUs left to check in. */
+	struct swait_queue_head expedited_wq;	/* Wait for check-ins. */
+	int ncpus_snap;				/* # CPUs seen last time. */
+	u8 cbovld;				/* Callback overload now? */
+	u8 cbovldnext;				/* ^        ^  next time? */
+
+	unsigned long jiffies_force_qs;		/* Time at which to invoke */
+						/*  force_quiescent_state(). */
+	unsigned long jiffies_kick_kthreads;	/* Time at which to kick */
+						/*  kthreads, if configured. */
+	unsigned long n_force_qs;		/* Number of calls to */
+						/*  force_quiescent_state(). */
+	unsigned long gp_start;			/* Time at which GP started, */
+						/*  but in jiffies. */
+	unsigned long gp_end;			/* Time last GP ended, again */
+						/*  in jiffies. */
+	unsigned long gp_activity;		/* Time of last GP kthread */
+						/*  activity in jiffies. */
+	unsigned long gp_req_activity;		/* Time of last GP request */
+						/*  in jiffies. */
+	unsigned long jiffies_stall;		/* Time at which to check */
+						/*  for CPU stalls. */
+	int nr_fqs_jiffies_stall;		/* Number of fqs loops after
+						 * which read jiffies and set
+						 * jiffies_stall. Stall
+						 * warnings disabled if !0. */
+	unsigned long jiffies_resched;		/* Time at which to resched */
+						/*  a reluctant CPU. */
+	unsigned long n_force_qs_gpstart;	/* Snapshot of n_force_qs at */
+						/*  GP start. */
+	const char *name;			/* Name of structure. */
+	char abbr;				/* Abbreviated name. */
+
+	arch_spinlock_t ofl_lock ____cacheline_internodealigned_in_smp;
+						/* Synchronize offline with */
+						/*  GP pre-initialization. */
+	int nocb_is_setup;			/* nocb is setup from boot */
+};
+
+/* Values for rcu_state structure's gp_flags field. */
+#define RCU_GP_FLAG_INIT 0x1	/* Need grace-period initialization. */
+#define RCU_GP_FLAG_FQS  0x2	/* Need grace-period quiescent-state forcing. */
+#define RCU_GP_FLAG_OVLD 0x4	/* Experiencing callback overload. */
+
+/* Values for rcu_state structure's gp_state field. */
+#define RCU_GP_IDLE	 0	/* Initial state and no GP in progress. */
+#define RCU_GP_WAIT_GPS  1	/* Wait for grace-period start. */
+#define RCU_GP_DONE_GPS  2	/* Wait done for grace-period start. */
+#define RCU_GP_ONOFF     3	/* Grace-period initialization hotplug. */
+#define RCU_GP_INIT      4	/* Grace-period initialization. */
+#define RCU_GP_WAIT_FQS  5	/* Wait for force-quiescent-state time. */
+#define RCU_GP_DOING_FQS 6	/* Wait done for force-quiescent-state time. */
+#define RCU_GP_CLEANUP   7	/* Grace-period cleanup started. */
+#define RCU_GP_CLEANED   8	/* Grace-period cleanup complete. */
+
+/*
+ * In order to export the rcu_state name to the tracing tools, it
+ * needs to be added in the __tracepoint_string section.
+ * This requires defining a separate variable tp_<sname>_varname
+ * that points to the string being used, and this will allow
+ * the tracing userspace tools to be able to decipher the string
+ * address to the matching string.
+ */
+#ifdef CONFIG_PREEMPT_RCU
+#define RCU_ABBR 'p'
+#define RCU_NAME_RAW "rcu_preempt"
+#else /* #ifdef CONFIG_PREEMPT_RCU */
+#define RCU_ABBR 's'
+#define RCU_NAME_RAW "rcu_sched"
+#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+#ifndef CONFIG_TRACING
+#define RCU_NAME RCU_NAME_RAW
+#else /* #ifdef CONFIG_TRACING */
+static char rcu_name[] = RCU_NAME_RAW;
+static const char *tp_rcu_varname __used __tracepoint_string = rcu_name;
+#define RCU_NAME rcu_name
+#endif /* #else #ifdef CONFIG_TRACING */
+
+/* Forward declarations for tree_plugin.h */
+static void rcu_bootup_announce(void);
+static void rcu_qs(void);
+static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp);
+#ifdef CONFIG_HOTPLUG_CPU
+static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+static int rcu_print_task_exp_stall(struct rcu_node *rnp);
+static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp);
+static void rcu_flavor_sched_clock_irq(int user);
+static void dump_blkd_tasks(struct rcu_node *rnp, int ncheck);
+static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags);
+static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
+static bool rcu_is_callbacks_kthread(struct rcu_data *rdp);
+static void rcu_cpu_kthread_setup(unsigned int cpu);
+static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp);
+static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
+static bool rcu_preempt_need_deferred_qs(struct task_struct *t);
+static void zero_cpu_stall_ticks(struct rcu_data *rdp);
+static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp);
+static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq);
+static void rcu_init_one_nocb(struct rcu_node *rnp);
+static bool rcu_nocb_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
+				  unsigned long j);
+static bool rcu_nocb_try_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
+				bool *was_alldone, unsigned long flags);
+static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_empty,
+				 unsigned long flags);
+static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp, int level);
+static bool do_nocb_deferred_wakeup(struct rcu_data *rdp);
+static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp);
+static void rcu_spawn_cpu_nocb_kthread(int cpu);
+static void show_rcu_nocb_state(struct rcu_data *rdp);
+static void rcu_nocb_lock(struct rcu_data *rdp);
+static void rcu_nocb_unlock(struct rcu_data *rdp);
+static void rcu_nocb_unlock_irqrestore(struct rcu_data *rdp,
+				       unsigned long flags);
+static void rcu_lockdep_assert_cblist_protected(struct rcu_data *rdp);
+#ifdef CONFIG_RCU_NOCB_CPU
+static void __init rcu_organize_nocb_kthreads(void);
+
+/*
+ * Disable IRQs before checking offloaded state so that local
+ * locking is safe against concurrent de-offloading.
+ */
+#define rcu_nocb_lock_irqsave(rdp, flags)			\
+do {								\
+	local_irq_save(flags);					\
+	if (rcu_segcblist_is_offloaded(&(rdp)->cblist))	\
+		raw_spin_lock(&(rdp)->nocb_lock);		\
+} while (0)
+#else /* #ifdef CONFIG_RCU_NOCB_CPU */
+#define rcu_nocb_lock_irqsave(rdp, flags) local_irq_save(flags)
+#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
+
+static void rcu_bind_gp_kthread(void);
+static bool rcu_nohz_full_cpu(void);
+
+/* Forward declarations for tree_stall.h */
+static void record_gp_stall_check_time(void);
+static void rcu_iw_handler(struct irq_work *iwp);
+static void check_cpu_stall(struct rcu_data *rdp);
+static void rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp,
+				     const unsigned long gpssdelay);
+
+/* Forward declarations for tree_exp.h. */
+static void sync_rcu_do_polled_gp(struct work_struct *wp);
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
new file mode 100644
index 000000000..6d2cbed96
--- /dev/null
+++ b/kernel/rcu/tree_exp.h
@@ -0,0 +1,1109 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * RCU expedited grace periods
+ *
+ * Copyright IBM Corporation, 2016
+ *
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
+ */
+
+#include <linux/lockdep.h>
+
+static void rcu_exp_handler(void *unused);
+static int rcu_print_task_exp_stall(struct rcu_node *rnp);
+
+/*
+ * Record the start of an expedited grace period.
+ */
+static void rcu_exp_gp_seq_start(void)
+{
+	rcu_seq_start(&rcu_state.expedited_sequence);
+	rcu_poll_gp_seq_start_unlocked(&rcu_state.gp_seq_polled_exp_snap);
+}
+
+/*
+ * Return the value that the expedited-grace-period counter will have
+ * at the end of the current grace period.
+ */
+static __maybe_unused unsigned long rcu_exp_gp_seq_endval(void)
+{
+	return rcu_seq_endval(&rcu_state.expedited_sequence);
+}
+
+/*
+ * Record the end of an expedited grace period.
+ */
+static void rcu_exp_gp_seq_end(void)
+{
+	rcu_poll_gp_seq_end_unlocked(&rcu_state.gp_seq_polled_exp_snap);
+	rcu_seq_end(&rcu_state.expedited_sequence);
+	smp_mb(); /* Ensure that consecutive grace periods serialize. */
+}
+
+/*
+ * Take a snapshot of the expedited-grace-period counter, which is the
+ * earliest value that will indicate that a full grace period has
+ * elapsed since the current time.
+ */
+static unsigned long rcu_exp_gp_seq_snap(void)
+{
+	unsigned long s;
+
+	smp_mb(); /* Caller's modifications seen first by other CPUs. */
+	s = rcu_seq_snap(&rcu_state.expedited_sequence);
+	trace_rcu_exp_grace_period(rcu_state.name, s, TPS("snap"));
+	return s;
+}
+
+/*
+ * Given a counter snapshot from rcu_exp_gp_seq_snap(), return true
+ * if a full expedited grace period has elapsed since that snapshot
+ * was taken.
+ */
+static bool rcu_exp_gp_seq_done(unsigned long s)
+{
+	return rcu_seq_done(&rcu_state.expedited_sequence, s);
+}
+
+/*
+ * Reset the ->expmaskinit values in the rcu_node tree to reflect any
+ * recent CPU-online activity.  Note that these masks are not cleared
+ * when CPUs go offline, so they reflect the union of all CPUs that have
+ * ever been online.  This means that this function normally takes its
+ * no-work-to-do fastpath.
+ */
+static void sync_exp_reset_tree_hotplug(void)
+{
+	bool done;
+	unsigned long flags;
+	unsigned long mask;
+	unsigned long oldmask;
+	int ncpus = smp_load_acquire(&rcu_state.ncpus); /* Order vs. locking. */
+	struct rcu_node *rnp;
+	struct rcu_node *rnp_up;
+
+	/* If no new CPUs onlined since last time, nothing to do. */
+	if (likely(ncpus == rcu_state.ncpus_snap))
+		return;
+	rcu_state.ncpus_snap = ncpus;
+
+	/*
+	 * Each pass through the following loop propagates newly onlined
+	 * CPUs for the current rcu_node structure up the rcu_node tree.
+	 */
+	rcu_for_each_leaf_node(rnp) {
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+		if (rnp->expmaskinit == rnp->expmaskinitnext) {
+			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+			continue;  /* No new CPUs, nothing to do. */
+		}
+
+		/* Update this node's mask, track old value for propagation. */
+		oldmask = rnp->expmaskinit;
+		rnp->expmaskinit = rnp->expmaskinitnext;
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+
+		/* If was already nonzero, nothing to propagate. */
+		if (oldmask)
+			continue;
+
+		/* Propagate the new CPU up the tree. */
+		mask = rnp->grpmask;
+		rnp_up = rnp->parent;
+		done = false;
+		while (rnp_up) {
+			raw_spin_lock_irqsave_rcu_node(rnp_up, flags);
+			if (rnp_up->expmaskinit)
+				done = true;
+			rnp_up->expmaskinit |= mask;
+			raw_spin_unlock_irqrestore_rcu_node(rnp_up, flags);
+			if (done)
+				break;
+			mask = rnp_up->grpmask;
+			rnp_up = rnp_up->parent;
+		}
+	}
+}
+
+/*
+ * Reset the ->expmask values in the rcu_node tree in preparation for
+ * a new expedited grace period.
+ */
+static void __maybe_unused sync_exp_reset_tree(void)
+{
+	unsigned long flags;
+	struct rcu_node *rnp;
+
+	sync_exp_reset_tree_hotplug();
+	rcu_for_each_node_breadth_first(rnp) {
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+		WARN_ON_ONCE(rnp->expmask);
+		WRITE_ONCE(rnp->expmask, rnp->expmaskinit);
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	}
+}
+
+/*
+ * Return non-zero if there is no RCU expedited grace period in progress
+ * for the specified rcu_node structure, in other words, if all CPUs and
+ * tasks covered by the specified rcu_node structure have done their bit
+ * for the current expedited grace period.
+ */
+static bool sync_rcu_exp_done(struct rcu_node *rnp)
+{
+	raw_lockdep_assert_held_rcu_node(rnp);
+	return READ_ONCE(rnp->exp_tasks) == NULL &&
+	       READ_ONCE(rnp->expmask) == 0;
+}
+
+/*
+ * Like sync_rcu_exp_done(), but where the caller does not hold the
+ * rcu_node's ->lock.
+ */
+static bool sync_rcu_exp_done_unlocked(struct rcu_node *rnp)
+{
+	unsigned long flags;
+	bool ret;
+
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	ret = sync_rcu_exp_done(rnp);
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+
+	return ret;
+}
+
+/*
+ * Report the exit from RCU read-side critical section for the last task
+ * that queued itself during or before the current expedited preemptible-RCU
+ * grace period.  This event is reported either to the rcu_node structure on
+ * which the task was queued or to one of that rcu_node structure's ancestors,
+ * recursively up the tree.  (Calm down, calm down, we do the recursion
+ * iteratively!)
+ */
+static void __rcu_report_exp_rnp(struct rcu_node *rnp,
+				 bool wake, unsigned long flags)
+	__releases(rnp->lock)
+{
+	unsigned long mask;
+
+	raw_lockdep_assert_held_rcu_node(rnp);
+	for (;;) {
+		if (!sync_rcu_exp_done(rnp)) {
+			if (!rnp->expmask)
+				rcu_initiate_boost(rnp, flags);
+			else
+				raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+			break;
+		}
+		if (rnp->parent == NULL) {
+			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+			if (wake) {
+				smp_mb(); /* EGP done before wake_up(). */
+				swake_up_one_online(&rcu_state.expedited_wq);
+			}
+			break;
+		}
+		mask = rnp->grpmask;
+		raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled */
+		rnp = rnp->parent;
+		raw_spin_lock_rcu_node(rnp); /* irqs already disabled */
+		WARN_ON_ONCE(!(rnp->expmask & mask));
+		WRITE_ONCE(rnp->expmask, rnp->expmask & ~mask);
+	}
+}
+
+/*
+ * Report expedited quiescent state for specified node.  This is a
+ * lock-acquisition wrapper function for __rcu_report_exp_rnp().
+ */
+static void __maybe_unused rcu_report_exp_rnp(struct rcu_node *rnp, bool wake)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	__rcu_report_exp_rnp(rnp, wake, flags);
+}
+
+/*
+ * Report expedited quiescent state for multiple CPUs, all covered by the
+ * specified leaf rcu_node structure.
+ */
+static void rcu_report_exp_cpu_mult(struct rcu_node *rnp,
+				    unsigned long mask, bool wake)
+{
+	int cpu;
+	unsigned long flags;
+	struct rcu_data *rdp;
+
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	if (!(rnp->expmask & mask)) {
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		return;
+	}
+	WRITE_ONCE(rnp->expmask, rnp->expmask & ~mask);
+	for_each_leaf_node_cpu_mask(rnp, cpu, mask) {
+		rdp = per_cpu_ptr(&rcu_data, cpu);
+		if (!IS_ENABLED(CONFIG_NO_HZ_FULL) || !rdp->rcu_forced_tick_exp)
+			continue;
+		rdp->rcu_forced_tick_exp = false;
+		tick_dep_clear_cpu(cpu, TICK_DEP_BIT_RCU_EXP);
+	}
+	__rcu_report_exp_rnp(rnp, wake, flags); /* Releases rnp->lock. */
+}
+
+/*
+ * Report expedited quiescent state for specified rcu_data (CPU).
+ */
+static void rcu_report_exp_rdp(struct rcu_data *rdp)
+{
+	WRITE_ONCE(rdp->cpu_no_qs.b.exp, false);
+	rcu_report_exp_cpu_mult(rdp->mynode, rdp->grpmask, true);
+}
+
+/* Common code for work-done checking. */
+static bool sync_exp_work_done(unsigned long s)
+{
+	if (rcu_exp_gp_seq_done(s)) {
+		trace_rcu_exp_grace_period(rcu_state.name, s, TPS("done"));
+		smp_mb(); /* Ensure test happens before caller kfree(). */
+		return true;
+	}
+	return false;
+}
+
+/*
+ * Funnel-lock acquisition for expedited grace periods.  Returns true
+ * if some other task completed an expedited grace period that this task
+ * can piggy-back on, and with no mutex held.  Otherwise, returns false
+ * with the mutex held, indicating that the caller must actually do the
+ * expedited grace period.
+ */
+static bool exp_funnel_lock(unsigned long s)
+{
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, raw_smp_processor_id());
+	struct rcu_node *rnp = rdp->mynode;
+	struct rcu_node *rnp_root = rcu_get_root();
+
+	/* Low-contention fastpath. */
+	if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s) &&
+	    (rnp == rnp_root ||
+	     ULONG_CMP_LT(READ_ONCE(rnp_root->exp_seq_rq), s)) &&
+	    mutex_trylock(&rcu_state.exp_mutex))
+		goto fastpath;
+
+	/*
+	 * Each pass through the following loop works its way up
+	 * the rcu_node tree, returning if others have done the work or
+	 * otherwise falls through to acquire ->exp_mutex.  The mapping
+	 * from CPU to rcu_node structure can be inexact, as it is just
+	 * promoting locality and is not strictly needed for correctness.
+	 */
+	for (; rnp != NULL; rnp = rnp->parent) {
+		if (sync_exp_work_done(s))
+			return true;
+
+		/* Work not done, either wait here or go up. */
+		spin_lock(&rnp->exp_lock);
+		if (ULONG_CMP_GE(rnp->exp_seq_rq, s)) {
+
+			/* Someone else doing GP, so wait for them. */
+			spin_unlock(&rnp->exp_lock);
+			trace_rcu_exp_funnel_lock(rcu_state.name, rnp->level,
+						  rnp->grplo, rnp->grphi,
+						  TPS("wait"));
+			wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3],
+				   sync_exp_work_done(s));
+			return true;
+		}
+		WRITE_ONCE(rnp->exp_seq_rq, s); /* Followers can wait on us. */
+		spin_unlock(&rnp->exp_lock);
+		trace_rcu_exp_funnel_lock(rcu_state.name, rnp->level,
+					  rnp->grplo, rnp->grphi, TPS("nxtlvl"));
+	}
+	mutex_lock(&rcu_state.exp_mutex);
+fastpath:
+	if (sync_exp_work_done(s)) {
+		mutex_unlock(&rcu_state.exp_mutex);
+		return true;
+	}
+	rcu_exp_gp_seq_start();
+	trace_rcu_exp_grace_period(rcu_state.name, s, TPS("start"));
+	return false;
+}
+
+/*
+ * Select the CPUs within the specified rcu_node that the upcoming
+ * expedited grace period needs to wait for.
+ */
+static void __sync_rcu_exp_select_node_cpus(struct rcu_exp_work *rewp)
+{
+	int cpu;
+	unsigned long flags;
+	unsigned long mask_ofl_test;
+	unsigned long mask_ofl_ipi;
+	int ret;
+	struct rcu_node *rnp = container_of(rewp, struct rcu_node, rew);
+
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+
+	/* Each pass checks a CPU for identity, offline, and idle. */
+	mask_ofl_test = 0;
+	for_each_leaf_node_cpu_mask(rnp, cpu, rnp->expmask) {
+		struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+		unsigned long mask = rdp->grpmask;
+		int snap;
+
+		if (raw_smp_processor_id() == cpu ||
+		    !(rnp->qsmaskinitnext & mask)) {
+			mask_ofl_test |= mask;
+		} else {
+			snap = rcu_dynticks_snap(cpu);
+			if (rcu_dynticks_in_eqs(snap))
+				mask_ofl_test |= mask;
+			else
+				rdp->exp_dynticks_snap = snap;
+		}
+	}
+	mask_ofl_ipi = rnp->expmask & ~mask_ofl_test;
+
+	/*
+	 * Need to wait for any blocked tasks as well.	Note that
+	 * additional blocking tasks will also block the expedited GP
+	 * until such time as the ->expmask bits are cleared.
+	 */
+	if (rcu_preempt_has_tasks(rnp))
+		WRITE_ONCE(rnp->exp_tasks, rnp->blkd_tasks.next);
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+
+	/* IPI the remaining CPUs for expedited quiescent state. */
+	for_each_leaf_node_cpu_mask(rnp, cpu, mask_ofl_ipi) {
+		struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+		unsigned long mask = rdp->grpmask;
+
+retry_ipi:
+		if (rcu_dynticks_in_eqs_since(rdp, rdp->exp_dynticks_snap)) {
+			mask_ofl_test |= mask;
+			continue;
+		}
+		if (get_cpu() == cpu) {
+			mask_ofl_test |= mask;
+			put_cpu();
+			continue;
+		}
+		ret = smp_call_function_single(cpu, rcu_exp_handler, NULL, 0);
+		put_cpu();
+		/* The CPU will report the QS in response to the IPI. */
+		if (!ret)
+			continue;
+
+		/* Failed, raced with CPU hotplug operation. */
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+		if ((rnp->qsmaskinitnext & mask) &&
+		    (rnp->expmask & mask)) {
+			/* Online, so delay for a bit and try again. */
+			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+			trace_rcu_exp_grace_period(rcu_state.name, rcu_exp_gp_seq_endval(), TPS("selectofl"));
+			schedule_timeout_idle(1);
+			goto retry_ipi;
+		}
+		/* CPU really is offline, so we must report its QS. */
+		if (rnp->expmask & mask)
+			mask_ofl_test |= mask;
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	}
+	/* Report quiescent states for those that went offline. */
+	if (mask_ofl_test)
+		rcu_report_exp_cpu_mult(rnp, mask_ofl_test, false);
+}
+
+static void rcu_exp_sel_wait_wake(unsigned long s);
+
+#ifdef CONFIG_RCU_EXP_KTHREAD
+static void sync_rcu_exp_select_node_cpus(struct kthread_work *wp)
+{
+	struct rcu_exp_work *rewp =
+		container_of(wp, struct rcu_exp_work, rew_work);
+
+	__sync_rcu_exp_select_node_cpus(rewp);
+}
+
+static inline bool rcu_gp_par_worker_started(void)
+{
+	return !!READ_ONCE(rcu_exp_par_gp_kworker);
+}
+
+static inline void sync_rcu_exp_select_cpus_queue_work(struct rcu_node *rnp)
+{
+	kthread_init_work(&rnp->rew.rew_work, sync_rcu_exp_select_node_cpus);
+	/*
+	 * Use rcu_exp_par_gp_kworker, because flushing a work item from
+	 * another work item on the same kthread worker can result in
+	 * deadlock.
+	 */
+	kthread_queue_work(rcu_exp_par_gp_kworker, &rnp->rew.rew_work);
+}
+
+static inline void sync_rcu_exp_select_cpus_flush_work(struct rcu_node *rnp)
+{
+	kthread_flush_work(&rnp->rew.rew_work);
+}
+
+/*
+ * Work-queue handler to drive an expedited grace period forward.
+ */
+static void wait_rcu_exp_gp(struct kthread_work *wp)
+{
+	struct rcu_exp_work *rewp;
+
+	rewp = container_of(wp, struct rcu_exp_work, rew_work);
+	rcu_exp_sel_wait_wake(rewp->rew_s);
+}
+
+static inline void synchronize_rcu_expedited_queue_work(struct rcu_exp_work *rew)
+{
+	kthread_init_work(&rew->rew_work, wait_rcu_exp_gp);
+	kthread_queue_work(rcu_exp_gp_kworker, &rew->rew_work);
+}
+
+static inline void synchronize_rcu_expedited_destroy_work(struct rcu_exp_work *rew)
+{
+}
+#else /* !CONFIG_RCU_EXP_KTHREAD */
+static void sync_rcu_exp_select_node_cpus(struct work_struct *wp)
+{
+	struct rcu_exp_work *rewp =
+		container_of(wp, struct rcu_exp_work, rew_work);
+
+	__sync_rcu_exp_select_node_cpus(rewp);
+}
+
+static inline bool rcu_gp_par_worker_started(void)
+{
+	return !!READ_ONCE(rcu_par_gp_wq);
+}
+
+static inline void sync_rcu_exp_select_cpus_queue_work(struct rcu_node *rnp)
+{
+	int cpu = find_next_bit(&rnp->ffmask, BITS_PER_LONG, -1);
+
+	INIT_WORK(&rnp->rew.rew_work, sync_rcu_exp_select_node_cpus);
+	/* If all offline, queue the work on an unbound CPU. */
+	if (unlikely(cpu > rnp->grphi - rnp->grplo))
+		cpu = WORK_CPU_UNBOUND;
+	else
+		cpu += rnp->grplo;
+	queue_work_on(cpu, rcu_par_gp_wq, &rnp->rew.rew_work);
+}
+
+static inline void sync_rcu_exp_select_cpus_flush_work(struct rcu_node *rnp)
+{
+	flush_work(&rnp->rew.rew_work);
+}
+
+/*
+ * Work-queue handler to drive an expedited grace period forward.
+ */
+static void wait_rcu_exp_gp(struct work_struct *wp)
+{
+	struct rcu_exp_work *rewp;
+
+	rewp = container_of(wp, struct rcu_exp_work, rew_work);
+	rcu_exp_sel_wait_wake(rewp->rew_s);
+}
+
+static inline void synchronize_rcu_expedited_queue_work(struct rcu_exp_work *rew)
+{
+	INIT_WORK_ONSTACK(&rew->rew_work, wait_rcu_exp_gp);
+	queue_work(rcu_gp_wq, &rew->rew_work);
+}
+
+static inline void synchronize_rcu_expedited_destroy_work(struct rcu_exp_work *rew)
+{
+	destroy_work_on_stack(&rew->rew_work);
+}
+#endif /* CONFIG_RCU_EXP_KTHREAD */
+
+/*
+ * Select the nodes that the upcoming expedited grace period needs
+ * to wait for.
+ */
+static void sync_rcu_exp_select_cpus(void)
+{
+	struct rcu_node *rnp;
+
+	trace_rcu_exp_grace_period(rcu_state.name, rcu_exp_gp_seq_endval(), TPS("reset"));
+	sync_exp_reset_tree();
+	trace_rcu_exp_grace_period(rcu_state.name, rcu_exp_gp_seq_endval(), TPS("select"));
+
+	/* Schedule work for each leaf rcu_node structure. */
+	rcu_for_each_leaf_node(rnp) {
+		rnp->exp_need_flush = false;
+		if (!READ_ONCE(rnp->expmask))
+			continue; /* Avoid early boot non-existent wq. */
+		if (!rcu_gp_par_worker_started() ||
+		    rcu_scheduler_active != RCU_SCHEDULER_RUNNING ||
+		    rcu_is_last_leaf_node(rnp)) {
+			/* No worker started yet or last leaf, do direct call. */
+			sync_rcu_exp_select_node_cpus(&rnp->rew.rew_work);
+			continue;
+		}
+		sync_rcu_exp_select_cpus_queue_work(rnp);
+		rnp->exp_need_flush = true;
+	}
+
+	/* Wait for jobs (if any) to complete. */
+	rcu_for_each_leaf_node(rnp)
+		if (rnp->exp_need_flush)
+			sync_rcu_exp_select_cpus_flush_work(rnp);
+}
+
+/*
+ * Wait for the expedited grace period to elapse, within time limit.
+ * If the time limit is exceeded without the grace period elapsing,
+ * return false, otherwise return true.
+ */
+static bool synchronize_rcu_expedited_wait_once(long tlimit)
+{
+	int t;
+	struct rcu_node *rnp_root = rcu_get_root();
+
+	t = swait_event_timeout_exclusive(rcu_state.expedited_wq,
+					  sync_rcu_exp_done_unlocked(rnp_root),
+					  tlimit);
+	// Workqueues should not be signaled.
+	if (t > 0 || sync_rcu_exp_done_unlocked(rnp_root))
+		return true;
+	WARN_ON(t < 0);  /* workqueues should not be signaled. */
+	return false;
+}
+
+/*
+ * Wait for the expedited grace period to elapse, issuing any needed
+ * RCU CPU stall warnings along the way.
+ */
+static void synchronize_rcu_expedited_wait(void)
+{
+	int cpu;
+	unsigned long j;
+	unsigned long jiffies_stall;
+	unsigned long jiffies_start;
+	unsigned long mask;
+	int ndetected;
+	struct rcu_data *rdp;
+	struct rcu_node *rnp;
+	struct rcu_node *rnp_root = rcu_get_root();
+
+	trace_rcu_exp_grace_period(rcu_state.name, rcu_exp_gp_seq_endval(), TPS("startwait"));
+	jiffies_stall = rcu_exp_jiffies_till_stall_check();
+	jiffies_start = jiffies;
+	if (tick_nohz_full_enabled() && rcu_inkernel_boot_has_ended()) {
+		if (synchronize_rcu_expedited_wait_once(1))
+			return;
+		rcu_for_each_leaf_node(rnp) {
+			mask = READ_ONCE(rnp->expmask);
+			for_each_leaf_node_cpu_mask(rnp, cpu, mask) {
+				rdp = per_cpu_ptr(&rcu_data, cpu);
+				if (rdp->rcu_forced_tick_exp)
+					continue;
+				rdp->rcu_forced_tick_exp = true;
+				preempt_disable();
+				if (cpu_online(cpu))
+					tick_dep_set_cpu(cpu, TICK_DEP_BIT_RCU_EXP);
+				preempt_enable();
+			}
+		}
+		j = READ_ONCE(jiffies_till_first_fqs);
+		if (synchronize_rcu_expedited_wait_once(j + HZ))
+			return;
+	}
+
+	for (;;) {
+		if (synchronize_rcu_expedited_wait_once(jiffies_stall))
+			return;
+		if (rcu_stall_is_suppressed())
+			continue;
+		trace_rcu_stall_warning(rcu_state.name, TPS("ExpeditedStall"));
+		pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {",
+		       rcu_state.name);
+		ndetected = 0;
+		rcu_for_each_leaf_node(rnp) {
+			ndetected += rcu_print_task_exp_stall(rnp);
+			for_each_leaf_node_possible_cpu(rnp, cpu) {
+				struct rcu_data *rdp;
+
+				mask = leaf_node_cpu_bit(rnp, cpu);
+				if (!(READ_ONCE(rnp->expmask) & mask))
+					continue;
+				ndetected++;
+				rdp = per_cpu_ptr(&rcu_data, cpu);
+				pr_cont(" %d-%c%c%c%c", cpu,
+					"O."[!!cpu_online(cpu)],
+					"o."[!!(rdp->grpmask & rnp->expmaskinit)],
+					"N."[!!(rdp->grpmask & rnp->expmaskinitnext)],
+					"D."[!!data_race(rdp->cpu_no_qs.b.exp)]);
+			}
+		}
+		pr_cont(" } %lu jiffies s: %lu root: %#lx/%c\n",
+			jiffies - jiffies_start, rcu_state.expedited_sequence,
+			data_race(rnp_root->expmask),
+			".T"[!!data_race(rnp_root->exp_tasks)]);
+		if (ndetected) {
+			pr_err("blocking rcu_node structures (internal RCU debug):");
+			rcu_for_each_node_breadth_first(rnp) {
+				if (rnp == rnp_root)
+					continue; /* printed unconditionally */
+				if (sync_rcu_exp_done_unlocked(rnp))
+					continue;
+				pr_cont(" l=%u:%d-%d:%#lx/%c",
+					rnp->level, rnp->grplo, rnp->grphi,
+					data_race(rnp->expmask),
+					".T"[!!data_race(rnp->exp_tasks)]);
+			}
+			pr_cont("\n");
+		}
+		rcu_for_each_leaf_node(rnp) {
+			for_each_leaf_node_possible_cpu(rnp, cpu) {
+				mask = leaf_node_cpu_bit(rnp, cpu);
+				if (!(READ_ONCE(rnp->expmask) & mask))
+					continue;
+				preempt_disable(); // For smp_processor_id() in dump_cpu_task().
+				dump_cpu_task(cpu);
+				preempt_enable();
+			}
+		}
+		jiffies_stall = 3 * rcu_exp_jiffies_till_stall_check() + 3;
+		panic_on_rcu_stall();
+	}
+}
+
+/*
+ * Wait for the current expedited grace period to complete, and then
+ * wake up everyone who piggybacked on the just-completed expedited
+ * grace period.  Also update all the ->exp_seq_rq counters as needed
+ * in order to avoid counter-wrap problems.
+ */
+static void rcu_exp_wait_wake(unsigned long s)
+{
+	struct rcu_node *rnp;
+
+	synchronize_rcu_expedited_wait();
+
+	// Switch over to wakeup mode, allowing the next GP to proceed.
+	// End the previous grace period only after acquiring the mutex
+	// to ensure that only one GP runs concurrently with wakeups.
+	mutex_lock(&rcu_state.exp_wake_mutex);
+	rcu_exp_gp_seq_end();
+	trace_rcu_exp_grace_period(rcu_state.name, s, TPS("end"));
+
+	rcu_for_each_node_breadth_first(rnp) {
+		if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s)) {
+			spin_lock(&rnp->exp_lock);
+			/* Recheck, avoid hang in case someone just arrived. */
+			if (ULONG_CMP_LT(rnp->exp_seq_rq, s))
+				WRITE_ONCE(rnp->exp_seq_rq, s);
+			spin_unlock(&rnp->exp_lock);
+		}
+		smp_mb(); /* All above changes before wakeup. */
+		wake_up_all(&rnp->exp_wq[rcu_seq_ctr(s) & 0x3]);
+	}
+	trace_rcu_exp_grace_period(rcu_state.name, s, TPS("endwake"));
+	mutex_unlock(&rcu_state.exp_wake_mutex);
+}
+
+/*
+ * Common code to drive an expedited grace period forward, used by
+ * workqueues and mid-boot-time tasks.
+ */
+static void rcu_exp_sel_wait_wake(unsigned long s)
+{
+	/* Initialize the rcu_node tree in preparation for the wait. */
+	sync_rcu_exp_select_cpus();
+
+	/* Wait and clean up, including waking everyone. */
+	rcu_exp_wait_wake(s);
+}
+
+#ifdef CONFIG_PREEMPT_RCU
+
+/*
+ * Remote handler for smp_call_function_single().  If there is an
+ * RCU read-side critical section in effect, request that the
+ * next rcu_read_unlock() record the quiescent state up the
+ * ->expmask fields in the rcu_node tree.  Otherwise, immediately
+ * report the quiescent state.
+ */
+static void rcu_exp_handler(void *unused)
+{
+	int depth = rcu_preempt_depth();
+	unsigned long flags;
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
+	struct rcu_node *rnp = rdp->mynode;
+	struct task_struct *t = current;
+
+	/*
+	 * First, the common case of not being in an RCU read-side
+	 * critical section.  If also enabled or idle, immediately
+	 * report the quiescent state, otherwise defer.
+	 */
+	if (!depth) {
+		if (!(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK)) ||
+		    rcu_is_cpu_rrupt_from_idle()) {
+			rcu_report_exp_rdp(rdp);
+		} else {
+			WRITE_ONCE(rdp->cpu_no_qs.b.exp, true);
+			set_tsk_need_resched(t);
+			set_preempt_need_resched();
+		}
+		return;
+	}
+
+	/*
+	 * Second, the less-common case of being in an RCU read-side
+	 * critical section.  In this case we can count on a future
+	 * rcu_read_unlock().  However, this rcu_read_unlock() might
+	 * execute on some other CPU, but in that case there will be
+	 * a future context switch.  Either way, if the expedited
+	 * grace period is still waiting on this CPU, set ->deferred_qs
+	 * so that the eventual quiescent state will be reported.
+	 * Note that there is a large group of race conditions that
+	 * can have caused this quiescent state to already have been
+	 * reported, so we really do need to check ->expmask.
+	 */
+	if (depth > 0) {
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+		if (rnp->expmask & rdp->grpmask) {
+			WRITE_ONCE(rdp->cpu_no_qs.b.exp, true);
+			t->rcu_read_unlock_special.b.exp_hint = true;
+		}
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		return;
+	}
+
+	// Finally, negative nesting depth should not happen.
+	WARN_ON_ONCE(1);
+}
+
+/* PREEMPTION=y, so no PREEMPTION=n expedited grace period to clean up after. */
+static void sync_sched_exp_online_cleanup(int cpu)
+{
+}
+
+/*
+ * Scan the current list of tasks blocked within RCU read-side critical
+ * sections, printing out the tid of each that is blocking the current
+ * expedited grace period.
+ */
+static int rcu_print_task_exp_stall(struct rcu_node *rnp)
+{
+	unsigned long flags;
+	int ndetected = 0;
+	struct task_struct *t;
+
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	if (!rnp->exp_tasks) {
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		return 0;
+	}
+	t = list_entry(rnp->exp_tasks->prev,
+		       struct task_struct, rcu_node_entry);
+	list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) {
+		pr_cont(" P%d", t->pid);
+		ndetected++;
+	}
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	return ndetected;
+}
+
+#else /* #ifdef CONFIG_PREEMPT_RCU */
+
+/* Request an expedited quiescent state. */
+static void rcu_exp_need_qs(void)
+{
+	__this_cpu_write(rcu_data.cpu_no_qs.b.exp, true);
+	/* Store .exp before .rcu_urgent_qs. */
+	smp_store_release(this_cpu_ptr(&rcu_data.rcu_urgent_qs), true);
+	set_tsk_need_resched(current);
+	set_preempt_need_resched();
+}
+
+/* Invoked on each online non-idle CPU for expedited quiescent state. */
+static void rcu_exp_handler(void *unused)
+{
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
+	struct rcu_node *rnp = rdp->mynode;
+	bool preempt_bh_enabled = !(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK));
+
+	if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) ||
+	    __this_cpu_read(rcu_data.cpu_no_qs.b.exp))
+		return;
+	if (rcu_is_cpu_rrupt_from_idle() ||
+	    (IS_ENABLED(CONFIG_PREEMPT_COUNT) && preempt_bh_enabled)) {
+		rcu_report_exp_rdp(this_cpu_ptr(&rcu_data));
+		return;
+	}
+	rcu_exp_need_qs();
+}
+
+/* Send IPI for expedited cleanup if needed at end of CPU-hotplug operation. */
+static void sync_sched_exp_online_cleanup(int cpu)
+{
+	unsigned long flags;
+	int my_cpu;
+	struct rcu_data *rdp;
+	int ret;
+	struct rcu_node *rnp;
+
+	rdp = per_cpu_ptr(&rcu_data, cpu);
+	rnp = rdp->mynode;
+	my_cpu = get_cpu();
+	/* Quiescent state either not needed or already requested, leave. */
+	if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) ||
+	    READ_ONCE(rdp->cpu_no_qs.b.exp)) {
+		put_cpu();
+		return;
+	}
+	/* Quiescent state needed on current CPU, so set it up locally. */
+	if (my_cpu == cpu) {
+		local_irq_save(flags);
+		rcu_exp_need_qs();
+		local_irq_restore(flags);
+		put_cpu();
+		return;
+	}
+	/* Quiescent state needed on some other CPU, send IPI. */
+	ret = smp_call_function_single(cpu, rcu_exp_handler, NULL, 0);
+	put_cpu();
+	WARN_ON_ONCE(ret);
+}
+
+/*
+ * Because preemptible RCU does not exist, we never have to check for
+ * tasks blocked within RCU read-side critical sections that are
+ * blocking the current expedited grace period.
+ */
+static int rcu_print_task_exp_stall(struct rcu_node *rnp)
+{
+	return 0;
+}
+
+#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+
+/**
+ * synchronize_rcu_expedited - Brute-force RCU grace period
+ *
+ * Wait for an RCU grace period, but expedite it.  The basic idea is to
+ * IPI all non-idle non-nohz online CPUs.  The IPI handler checks whether
+ * the CPU is in an RCU critical section, and if so, it sets a flag that
+ * causes the outermost rcu_read_unlock() to report the quiescent state
+ * for RCU-preempt or asks the scheduler for help for RCU-sched.  On the
+ * other hand, if the CPU is not in an RCU read-side critical section,
+ * the IPI handler reports the quiescent state immediately.
+ *
+ * Although this is a great improvement over previous expedited
+ * implementations, it is still unfriendly to real-time workloads, so is
+ * thus not recommended for any sort of common-case code.  In fact, if
+ * you are using synchronize_rcu_expedited() in a loop, please restructure
+ * your code to batch your updates, and then use a single synchronize_rcu()
+ * instead.
+ *
+ * This has the same semantics as (but is more brutal than) synchronize_rcu().
+ */
+void synchronize_rcu_expedited(void)
+{
+	bool boottime = (rcu_scheduler_active == RCU_SCHEDULER_INIT);
+	unsigned long flags;
+	struct rcu_exp_work rew;
+	struct rcu_node *rnp;
+	unsigned long s;
+
+	RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+			 lock_is_held(&rcu_lock_map) ||
+			 lock_is_held(&rcu_sched_lock_map),
+			 "Illegal synchronize_rcu_expedited() in RCU read-side critical section");
+
+	/* Is the state is such that the call is a grace period? */
+	if (rcu_blocking_is_gp()) {
+		// Note well that this code runs with !PREEMPT && !SMP.
+		// In addition, all code that advances grace periods runs
+		// at process level.  Therefore, this expedited GP overlaps
+		// with other expedited GPs only by being fully nested within
+		// them, which allows reuse of ->gp_seq_polled_exp_snap.
+		rcu_poll_gp_seq_start_unlocked(&rcu_state.gp_seq_polled_exp_snap);
+		rcu_poll_gp_seq_end_unlocked(&rcu_state.gp_seq_polled_exp_snap);
+
+		local_irq_save(flags);
+		WARN_ON_ONCE(num_online_cpus() > 1);
+		rcu_state.expedited_sequence += (1 << RCU_SEQ_CTR_SHIFT);
+		local_irq_restore(flags);
+		return;  // Context allows vacuous grace periods.
+	}
+
+	/* If expedited grace periods are prohibited, fall back to normal. */
+	if (rcu_gp_is_normal()) {
+		wait_rcu_gp(call_rcu);
+		return;
+	}
+
+	/* Take a snapshot of the sequence number.  */
+	s = rcu_exp_gp_seq_snap();
+	if (exp_funnel_lock(s))
+		return;  /* Someone else did our work for us. */
+
+	/* Ensure that load happens before action based on it. */
+	if (unlikely(boottime)) {
+		/* Direct call during scheduler init and early_initcalls(). */
+		rcu_exp_sel_wait_wake(s);
+	} else {
+		/* Marshall arguments & schedule the expedited grace period. */
+		rew.rew_s = s;
+		synchronize_rcu_expedited_queue_work(&rew);
+	}
+
+	/* Wait for expedited grace period to complete. */
+	rnp = rcu_get_root();
+	wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3],
+		   sync_exp_work_done(s));
+	smp_mb(); /* Work actions happen before return. */
+
+	/* Let the next expedited grace period start. */
+	mutex_unlock(&rcu_state.exp_mutex);
+
+	if (likely(!boottime))
+		synchronize_rcu_expedited_destroy_work(&rew);
+}
+EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
+
+/*
+ * Ensure that start_poll_synchronize_rcu_expedited() has the expedited
+ * RCU grace periods that it needs.
+ */
+static void sync_rcu_do_polled_gp(struct work_struct *wp)
+{
+	unsigned long flags;
+	int i = 0;
+	struct rcu_node *rnp = container_of(wp, struct rcu_node, exp_poll_wq);
+	unsigned long s;
+
+	raw_spin_lock_irqsave(&rnp->exp_poll_lock, flags);
+	s = rnp->exp_seq_poll_rq;
+	rnp->exp_seq_poll_rq = RCU_GET_STATE_COMPLETED;
+	raw_spin_unlock_irqrestore(&rnp->exp_poll_lock, flags);
+	if (s == RCU_GET_STATE_COMPLETED)
+		return;
+	while (!poll_state_synchronize_rcu(s)) {
+		synchronize_rcu_expedited();
+		if (i == 10 || i == 20)
+			pr_info("%s: i = %d s = %lx gp_seq_polled = %lx\n", __func__, i, s, READ_ONCE(rcu_state.gp_seq_polled));
+		i++;
+	}
+	raw_spin_lock_irqsave(&rnp->exp_poll_lock, flags);
+	s = rnp->exp_seq_poll_rq;
+	if (poll_state_synchronize_rcu(s))
+		rnp->exp_seq_poll_rq = RCU_GET_STATE_COMPLETED;
+	raw_spin_unlock_irqrestore(&rnp->exp_poll_lock, flags);
+}
+
+/**
+ * start_poll_synchronize_rcu_expedited - Snapshot current RCU state and start expedited grace period
+ *
+ * Returns a cookie to pass to a call to cond_synchronize_rcu(),
+ * cond_synchronize_rcu_expedited(), or poll_state_synchronize_rcu(),
+ * allowing them to determine whether or not any sort of grace period has
+ * elapsed in the meantime.  If the needed expedited grace period is not
+ * already slated to start, initiates that grace period.
+ */
+unsigned long start_poll_synchronize_rcu_expedited(void)
+{
+	unsigned long flags;
+	struct rcu_data *rdp;
+	struct rcu_node *rnp;
+	unsigned long s;
+
+	s = get_state_synchronize_rcu();
+	rdp = per_cpu_ptr(&rcu_data, raw_smp_processor_id());
+	rnp = rdp->mynode;
+	if (rcu_init_invoked())
+		raw_spin_lock_irqsave(&rnp->exp_poll_lock, flags);
+	if (!poll_state_synchronize_rcu(s)) {
+		rnp->exp_seq_poll_rq = s;
+		if (rcu_init_invoked())
+			queue_work(rcu_gp_wq, &rnp->exp_poll_wq);
+	}
+	if (rcu_init_invoked())
+		raw_spin_unlock_irqrestore(&rnp->exp_poll_lock, flags);
+
+	return s;
+}
+EXPORT_SYMBOL_GPL(start_poll_synchronize_rcu_expedited);
+
+/**
+ * start_poll_synchronize_rcu_expedited_full - Take a full snapshot and start expedited grace period
+ * @rgosp: Place to put snapshot of grace-period state
+ *
+ * Places the normal and expedited grace-period states in rgosp.  This
+ * state value can be passed to a later call to cond_synchronize_rcu_full()
+ * or poll_state_synchronize_rcu_full() to determine whether or not a
+ * grace period (whether normal or expedited) has elapsed in the meantime.
+ * If the needed expedited grace period is not already slated to start,
+ * initiates that grace period.
+ */
+void start_poll_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp)
+{
+	get_state_synchronize_rcu_full(rgosp);
+	(void)start_poll_synchronize_rcu_expedited();
+}
+EXPORT_SYMBOL_GPL(start_poll_synchronize_rcu_expedited_full);
+
+/**
+ * cond_synchronize_rcu_expedited - Conditionally wait for an expedited RCU grace period
+ *
+ * @oldstate: value from get_state_synchronize_rcu(), start_poll_synchronize_rcu(), or start_poll_synchronize_rcu_expedited()
+ *
+ * If any type of full RCU grace period has elapsed since the earlier
+ * call to get_state_synchronize_rcu(), start_poll_synchronize_rcu(),
+ * or start_poll_synchronize_rcu_expedited(), just return.  Otherwise,
+ * invoke synchronize_rcu_expedited() to wait for a full grace period.
+ *
+ * Yes, this function does not take counter wrap into account.
+ * But counter wrap is harmless.  If the counter wraps, we have waited for
+ * more than 2 billion grace periods (and way more on a 64-bit system!),
+ * so waiting for a couple of additional grace periods should be just fine.
+ *
+ * This function provides the same memory-ordering guarantees that
+ * would be provided by a synchronize_rcu() that was invoked at the call
+ * to the function that provided @oldstate and that returned at the end
+ * of this function.
+ */
+void cond_synchronize_rcu_expedited(unsigned long oldstate)
+{
+	if (!poll_state_synchronize_rcu(oldstate))
+		synchronize_rcu_expedited();
+}
+EXPORT_SYMBOL_GPL(cond_synchronize_rcu_expedited);
+
+/**
+ * cond_synchronize_rcu_expedited_full - Conditionally wait for an expedited RCU grace period
+ * @rgosp: value from get_state_synchronize_rcu_full(), start_poll_synchronize_rcu_full(), or start_poll_synchronize_rcu_expedited_full()
+ *
+ * If a full RCU grace period has elapsed since the call to
+ * get_state_synchronize_rcu_full(), start_poll_synchronize_rcu_full(),
+ * or start_poll_synchronize_rcu_expedited_full() from which @rgosp was
+ * obtained, just return.  Otherwise, invoke synchronize_rcu_expedited()
+ * to wait for a full grace period.
+ *
+ * Yes, this function does not take counter wrap into account.
+ * But counter wrap is harmless.  If the counter wraps, we have waited for
+ * more than 2 billion grace periods (and way more on a 64-bit system!),
+ * so waiting for a couple of additional grace periods should be just fine.
+ *
+ * This function provides the same memory-ordering guarantees that
+ * would be provided by a synchronize_rcu() that was invoked at the call
+ * to the function that provided @rgosp and that returned at the end of
+ * this function.
+ */
+void cond_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp)
+{
+	if (!poll_state_synchronize_rcu_full(rgosp))
+		synchronize_rcu_expedited();
+}
+EXPORT_SYMBOL_GPL(cond_synchronize_rcu_expedited_full);
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
new file mode 100644
index 000000000..0a5f0ef41
--- /dev/null
+++ b/kernel/rcu/tree_nocb.h
@@ -0,0 +1,1607 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Read-Copy Update mechanism for mutual exclusion (tree-based version)
+ * Internal non-public definitions that provide either classic
+ * or preemptible semantics.
+ *
+ * Copyright Red Hat, 2009
+ * Copyright IBM Corporation, 2009
+ * Copyright SUSE, 2021
+ *
+ * Author: Ingo Molnar <mingo@elte.hu>
+ *	   Paul E. McKenney <paulmck@linux.ibm.com>
+ *	   Frederic Weisbecker <frederic@kernel.org>
+ */
+
+#ifdef CONFIG_RCU_NOCB_CPU
+static cpumask_var_t rcu_nocb_mask; /* CPUs to have callbacks offloaded. */
+static bool __read_mostly rcu_nocb_poll;    /* Offload kthread are to poll. */
+static inline int rcu_lockdep_is_held_nocb(struct rcu_data *rdp)
+{
+	return lockdep_is_held(&rdp->nocb_lock);
+}
+
+static inline bool rcu_current_is_nocb_kthread(struct rcu_data *rdp)
+{
+	/* Race on early boot between thread creation and assignment */
+	if (!rdp->nocb_cb_kthread || !rdp->nocb_gp_kthread)
+		return true;
+
+	if (current == rdp->nocb_cb_kthread || current == rdp->nocb_gp_kthread)
+		if (in_task())
+			return true;
+	return false;
+}
+
+/*
+ * Offload callback processing from the boot-time-specified set of CPUs
+ * specified by rcu_nocb_mask.  For the CPUs in the set, there are kthreads
+ * created that pull the callbacks from the corresponding CPU, wait for
+ * a grace period to elapse, and invoke the callbacks.  These kthreads
+ * are organized into GP kthreads, which manage incoming callbacks, wait for
+ * grace periods, and awaken CB kthreads, and the CB kthreads, which only
+ * invoke callbacks.  Each GP kthread invokes its own CBs.  The no-CBs CPUs
+ * do a wake_up() on their GP kthread when they insert a callback into any
+ * empty list, unless the rcu_nocb_poll boot parameter has been specified,
+ * in which case each kthread actively polls its CPU.  (Which isn't so great
+ * for energy efficiency, but which does reduce RCU's overhead on that CPU.)
+ *
+ * This is intended to be used in conjunction with Frederic Weisbecker's
+ * adaptive-idle work, which would seriously reduce OS jitter on CPUs
+ * running CPU-bound user-mode computations.
+ *
+ * Offloading of callbacks can also be used as an energy-efficiency
+ * measure because CPUs with no RCU callbacks queued are more aggressive
+ * about entering dyntick-idle mode.
+ */
+
+
+/*
+ * Parse the boot-time rcu_nocb_mask CPU list from the kernel parameters.
+ * If the list is invalid, a warning is emitted and all CPUs are offloaded.
+ */
+static int __init rcu_nocb_setup(char *str)
+{
+	alloc_bootmem_cpumask_var(&rcu_nocb_mask);
+	if (*str == '=') {
+		if (cpulist_parse(++str, rcu_nocb_mask)) {
+			pr_warn("rcu_nocbs= bad CPU range, all CPUs set\n");
+			cpumask_setall(rcu_nocb_mask);
+		}
+	}
+	rcu_state.nocb_is_setup = true;
+	return 1;
+}
+__setup("rcu_nocbs", rcu_nocb_setup);
+
+static int __init parse_rcu_nocb_poll(char *arg)
+{
+	rcu_nocb_poll = true;
+	return 0;
+}
+early_param("rcu_nocb_poll", parse_rcu_nocb_poll);
+
+/*
+ * Don't bother bypassing ->cblist if the call_rcu() rate is low.
+ * After all, the main point of bypassing is to avoid lock contention
+ * on ->nocb_lock, which only can happen at high call_rcu() rates.
+ */
+static int nocb_nobypass_lim_per_jiffy = 16 * 1000 / HZ;
+module_param(nocb_nobypass_lim_per_jiffy, int, 0);
+
+/*
+ * Acquire the specified rcu_data structure's ->nocb_bypass_lock.  If the
+ * lock isn't immediately available, increment ->nocb_lock_contended to
+ * flag the contention.
+ */
+static void rcu_nocb_bypass_lock(struct rcu_data *rdp)
+	__acquires(&rdp->nocb_bypass_lock)
+{
+	lockdep_assert_irqs_disabled();
+	if (raw_spin_trylock(&rdp->nocb_bypass_lock))
+		return;
+	atomic_inc(&rdp->nocb_lock_contended);
+	WARN_ON_ONCE(smp_processor_id() != rdp->cpu);
+	smp_mb__after_atomic(); /* atomic_inc() before lock. */
+	raw_spin_lock(&rdp->nocb_bypass_lock);
+	smp_mb__before_atomic(); /* atomic_dec() after lock. */
+	atomic_dec(&rdp->nocb_lock_contended);
+}
+
+/*
+ * Spinwait until the specified rcu_data structure's ->nocb_lock is
+ * not contended.  Please note that this is extremely special-purpose,
+ * relying on the fact that at most two kthreads and one CPU contend for
+ * this lock, and also that the two kthreads are guaranteed to have frequent
+ * grace-period-duration time intervals between successive acquisitions
+ * of the lock.  This allows us to use an extremely simple throttling
+ * mechanism, and further to apply it only to the CPU doing floods of
+ * call_rcu() invocations.  Don't try this at home!
+ */
+static void rcu_nocb_wait_contended(struct rcu_data *rdp)
+{
+	WARN_ON_ONCE(smp_processor_id() != rdp->cpu);
+	while (WARN_ON_ONCE(atomic_read(&rdp->nocb_lock_contended)))
+		cpu_relax();
+}
+
+/*
+ * Conditionally acquire the specified rcu_data structure's
+ * ->nocb_bypass_lock.
+ */
+static bool rcu_nocb_bypass_trylock(struct rcu_data *rdp)
+{
+	lockdep_assert_irqs_disabled();
+	return raw_spin_trylock(&rdp->nocb_bypass_lock);
+}
+
+/*
+ * Release the specified rcu_data structure's ->nocb_bypass_lock.
+ */
+static void rcu_nocb_bypass_unlock(struct rcu_data *rdp)
+	__releases(&rdp->nocb_bypass_lock)
+{
+	lockdep_assert_irqs_disabled();
+	raw_spin_unlock(&rdp->nocb_bypass_lock);
+}
+
+/*
+ * Acquire the specified rcu_data structure's ->nocb_lock, but only
+ * if it corresponds to a no-CBs CPU.
+ */
+static void rcu_nocb_lock(struct rcu_data *rdp)
+{
+	lockdep_assert_irqs_disabled();
+	if (!rcu_rdp_is_offloaded(rdp))
+		return;
+	raw_spin_lock(&rdp->nocb_lock);
+}
+
+/*
+ * Release the specified rcu_data structure's ->nocb_lock, but only
+ * if it corresponds to a no-CBs CPU.
+ */
+static void rcu_nocb_unlock(struct rcu_data *rdp)
+{
+	if (rcu_rdp_is_offloaded(rdp)) {
+		lockdep_assert_irqs_disabled();
+		raw_spin_unlock(&rdp->nocb_lock);
+	}
+}
+
+/*
+ * Release the specified rcu_data structure's ->nocb_lock and restore
+ * interrupts, but only if it corresponds to a no-CBs CPU.
+ */
+static void rcu_nocb_unlock_irqrestore(struct rcu_data *rdp,
+				       unsigned long flags)
+{
+	if (rcu_rdp_is_offloaded(rdp)) {
+		lockdep_assert_irqs_disabled();
+		raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags);
+	} else {
+		local_irq_restore(flags);
+	}
+}
+
+/* Lockdep check that ->cblist may be safely accessed. */
+static void rcu_lockdep_assert_cblist_protected(struct rcu_data *rdp)
+{
+	lockdep_assert_irqs_disabled();
+	if (rcu_rdp_is_offloaded(rdp))
+		lockdep_assert_held(&rdp->nocb_lock);
+}
+
+/*
+ * Wake up any no-CBs CPUs' kthreads that were waiting on the just-ended
+ * grace period.
+ */
+static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq)
+{
+	swake_up_all(sq);
+}
+
+static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp)
+{
+	return &rnp->nocb_gp_wq[rcu_seq_ctr(rnp->gp_seq) & 0x1];
+}
+
+static void rcu_init_one_nocb(struct rcu_node *rnp)
+{
+	init_swait_queue_head(&rnp->nocb_gp_wq[0]);
+	init_swait_queue_head(&rnp->nocb_gp_wq[1]);
+}
+
+static bool __wake_nocb_gp(struct rcu_data *rdp_gp,
+			   struct rcu_data *rdp,
+			   bool force, unsigned long flags)
+	__releases(rdp_gp->nocb_gp_lock)
+{
+	bool needwake = false;
+
+	if (!READ_ONCE(rdp_gp->nocb_gp_kthread)) {
+		raw_spin_unlock_irqrestore(&rdp_gp->nocb_gp_lock, flags);
+		trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
+				    TPS("AlreadyAwake"));
+		return false;
+	}
+
+	if (rdp_gp->nocb_defer_wakeup > RCU_NOCB_WAKE_NOT) {
+		WRITE_ONCE(rdp_gp->nocb_defer_wakeup, RCU_NOCB_WAKE_NOT);
+		del_timer(&rdp_gp->nocb_timer);
+	}
+
+	if (force || READ_ONCE(rdp_gp->nocb_gp_sleep)) {
+		WRITE_ONCE(rdp_gp->nocb_gp_sleep, false);
+		needwake = true;
+	}
+	raw_spin_unlock_irqrestore(&rdp_gp->nocb_gp_lock, flags);
+	if (needwake) {
+		trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("DoWake"));
+		wake_up_process(rdp_gp->nocb_gp_kthread);
+	}
+
+	return needwake;
+}
+
+/*
+ * Kick the GP kthread for this NOCB group.
+ */
+static bool wake_nocb_gp(struct rcu_data *rdp, bool force)
+{
+	unsigned long flags;
+	struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
+
+	raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags);
+	return __wake_nocb_gp(rdp_gp, rdp, force, flags);
+}
+
+/*
+ * Arrange to wake the GP kthread for this NOCB group at some future
+ * time when it is safe to do so.
+ */
+static void wake_nocb_gp_defer(struct rcu_data *rdp, int waketype,
+			       const char *reason)
+{
+	unsigned long flags;
+	struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
+
+	raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags);
+
+	/*
+	 * Bypass wakeup overrides previous deferments. In case
+	 * of callback storm, no need to wake up too early.
+	 */
+	if (waketype == RCU_NOCB_WAKE_BYPASS) {
+		mod_timer(&rdp_gp->nocb_timer, jiffies + 2);
+		WRITE_ONCE(rdp_gp->nocb_defer_wakeup, waketype);
+	} else {
+		if (rdp_gp->nocb_defer_wakeup < RCU_NOCB_WAKE)
+			mod_timer(&rdp_gp->nocb_timer, jiffies + 1);
+		if (rdp_gp->nocb_defer_wakeup < waketype)
+			WRITE_ONCE(rdp_gp->nocb_defer_wakeup, waketype);
+	}
+
+	raw_spin_unlock_irqrestore(&rdp_gp->nocb_gp_lock, flags);
+
+	trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, reason);
+}
+
+/*
+ * Flush the ->nocb_bypass queue into ->cblist, enqueuing rhp if non-NULL.
+ * However, if there is a callback to be enqueued and if ->nocb_bypass
+ * proves to be initially empty, just return false because the no-CB GP
+ * kthread may need to be awakened in this case.
+ *
+ * Note that this function always returns true if rhp is NULL.
+ */
+static bool rcu_nocb_do_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
+				     unsigned long j)
+{
+	struct rcu_cblist rcl;
+
+	WARN_ON_ONCE(!rcu_rdp_is_offloaded(rdp));
+	rcu_lockdep_assert_cblist_protected(rdp);
+	lockdep_assert_held(&rdp->nocb_bypass_lock);
+	if (rhp && !rcu_cblist_n_cbs(&rdp->nocb_bypass)) {
+		raw_spin_unlock(&rdp->nocb_bypass_lock);
+		return false;
+	}
+	/* Note: ->cblist.len already accounts for ->nocb_bypass contents. */
+	if (rhp)
+		rcu_segcblist_inc_len(&rdp->cblist); /* Must precede enqueue. */
+	rcu_cblist_flush_enqueue(&rcl, &rdp->nocb_bypass, rhp);
+	rcu_segcblist_insert_pend_cbs(&rdp->cblist, &rcl);
+	WRITE_ONCE(rdp->nocb_bypass_first, j);
+	rcu_nocb_bypass_unlock(rdp);
+	return true;
+}
+
+/*
+ * Flush the ->nocb_bypass queue into ->cblist, enqueuing rhp if non-NULL.
+ * However, if there is a callback to be enqueued and if ->nocb_bypass
+ * proves to be initially empty, just return false because the no-CB GP
+ * kthread may need to be awakened in this case.
+ *
+ * Note that this function always returns true if rhp is NULL.
+ */
+static bool rcu_nocb_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
+				  unsigned long j)
+{
+	if (!rcu_rdp_is_offloaded(rdp))
+		return true;
+	rcu_lockdep_assert_cblist_protected(rdp);
+	rcu_nocb_bypass_lock(rdp);
+	return rcu_nocb_do_flush_bypass(rdp, rhp, j);
+}
+
+/*
+ * If the ->nocb_bypass_lock is immediately available, flush the
+ * ->nocb_bypass queue into ->cblist.
+ */
+static void rcu_nocb_try_flush_bypass(struct rcu_data *rdp, unsigned long j)
+{
+	rcu_lockdep_assert_cblist_protected(rdp);
+	if (!rcu_rdp_is_offloaded(rdp) ||
+	    !rcu_nocb_bypass_trylock(rdp))
+		return;
+	WARN_ON_ONCE(!rcu_nocb_do_flush_bypass(rdp, NULL, j));
+}
+
+/*
+ * See whether it is appropriate to use the ->nocb_bypass list in order
+ * to control contention on ->nocb_lock.  A limited number of direct
+ * enqueues are permitted into ->cblist per jiffy.  If ->nocb_bypass
+ * is non-empty, further callbacks must be placed into ->nocb_bypass,
+ * otherwise rcu_barrier() breaks.  Use rcu_nocb_flush_bypass() to switch
+ * back to direct use of ->cblist.  However, ->nocb_bypass should not be
+ * used if ->cblist is empty, because otherwise callbacks can be stranded
+ * on ->nocb_bypass because we cannot count on the current CPU ever again
+ * invoking call_rcu().  The general rule is that if ->nocb_bypass is
+ * non-empty, the corresponding no-CBs grace-period kthread must not be
+ * in an indefinite sleep state.
+ *
+ * Finally, it is not permitted to use the bypass during early boot,
+ * as doing so would confuse the auto-initialization code.  Besides
+ * which, there is no point in worrying about lock contention while
+ * there is only one CPU in operation.
+ */
+static bool rcu_nocb_try_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
+				bool *was_alldone, unsigned long flags)
+{
+	unsigned long c;
+	unsigned long cur_gp_seq;
+	unsigned long j = jiffies;
+	long ncbs = rcu_cblist_n_cbs(&rdp->nocb_bypass);
+
+	lockdep_assert_irqs_disabled();
+
+	// Pure softirq/rcuc based processing: no bypassing, no
+	// locking.
+	if (!rcu_rdp_is_offloaded(rdp)) {
+		*was_alldone = !rcu_segcblist_pend_cbs(&rdp->cblist);
+		return false;
+	}
+
+	// In the process of (de-)offloading: no bypassing, but
+	// locking.
+	if (!rcu_segcblist_completely_offloaded(&rdp->cblist)) {
+		rcu_nocb_lock(rdp);
+		*was_alldone = !rcu_segcblist_pend_cbs(&rdp->cblist);
+		return false; /* Not offloaded, no bypassing. */
+	}
+
+	// Don't use ->nocb_bypass during early boot.
+	if (rcu_scheduler_active != RCU_SCHEDULER_RUNNING) {
+		rcu_nocb_lock(rdp);
+		WARN_ON_ONCE(rcu_cblist_n_cbs(&rdp->nocb_bypass));
+		*was_alldone = !rcu_segcblist_pend_cbs(&rdp->cblist);
+		return false;
+	}
+
+	// If we have advanced to a new jiffy, reset counts to allow
+	// moving back from ->nocb_bypass to ->cblist.
+	if (j == rdp->nocb_nobypass_last) {
+		c = rdp->nocb_nobypass_count + 1;
+	} else {
+		WRITE_ONCE(rdp->nocb_nobypass_last, j);
+		c = rdp->nocb_nobypass_count - nocb_nobypass_lim_per_jiffy;
+		if (ULONG_CMP_LT(rdp->nocb_nobypass_count,
+				 nocb_nobypass_lim_per_jiffy))
+			c = 0;
+		else if (c > nocb_nobypass_lim_per_jiffy)
+			c = nocb_nobypass_lim_per_jiffy;
+	}
+	WRITE_ONCE(rdp->nocb_nobypass_count, c);
+
+	// If there hasn't yet been all that many ->cblist enqueues
+	// this jiffy, tell the caller to enqueue onto ->cblist.  But flush
+	// ->nocb_bypass first.
+	if (rdp->nocb_nobypass_count < nocb_nobypass_lim_per_jiffy) {
+		rcu_nocb_lock(rdp);
+		*was_alldone = !rcu_segcblist_pend_cbs(&rdp->cblist);
+		if (*was_alldone)
+			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
+					    TPS("FirstQ"));
+		WARN_ON_ONCE(!rcu_nocb_flush_bypass(rdp, NULL, j));
+		WARN_ON_ONCE(rcu_cblist_n_cbs(&rdp->nocb_bypass));
+		return false; // Caller must enqueue the callback.
+	}
+
+	// If ->nocb_bypass has been used too long or is too full,
+	// flush ->nocb_bypass to ->cblist.
+	if ((ncbs && j != READ_ONCE(rdp->nocb_bypass_first)) ||
+	    ncbs >= qhimark) {
+		rcu_nocb_lock(rdp);
+		if (!rcu_nocb_flush_bypass(rdp, rhp, j)) {
+			*was_alldone = !rcu_segcblist_pend_cbs(&rdp->cblist);
+			if (*was_alldone)
+				trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
+						    TPS("FirstQ"));
+			WARN_ON_ONCE(rcu_cblist_n_cbs(&rdp->nocb_bypass));
+			return false; // Caller must enqueue the callback.
+		}
+		if (j != rdp->nocb_gp_adv_time &&
+		    rcu_segcblist_nextgp(&rdp->cblist, &cur_gp_seq) &&
+		    rcu_seq_done(&rdp->mynode->gp_seq, cur_gp_seq)) {
+			rcu_advance_cbs_nowake(rdp->mynode, rdp);
+			rdp->nocb_gp_adv_time = j;
+		}
+		rcu_nocb_unlock_irqrestore(rdp, flags);
+		return true; // Callback already enqueued.
+	}
+
+	// We need to use the bypass.
+	rcu_nocb_wait_contended(rdp);
+	rcu_nocb_bypass_lock(rdp);
+	ncbs = rcu_cblist_n_cbs(&rdp->nocb_bypass);
+	rcu_segcblist_inc_len(&rdp->cblist); /* Must precede enqueue. */
+	rcu_cblist_enqueue(&rdp->nocb_bypass, rhp);
+	if (!ncbs) {
+		WRITE_ONCE(rdp->nocb_bypass_first, j);
+		trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("FirstBQ"));
+	}
+	rcu_nocb_bypass_unlock(rdp);
+	smp_mb(); /* Order enqueue before wake. */
+	if (ncbs) {
+		local_irq_restore(flags);
+	} else {
+		// No-CBs GP kthread might be indefinitely asleep, if so, wake.
+		rcu_nocb_lock(rdp); // Rare during call_rcu() flood.
+		if (!rcu_segcblist_pend_cbs(&rdp->cblist)) {
+			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
+					    TPS("FirstBQwake"));
+			__call_rcu_nocb_wake(rdp, true, flags);
+		} else {
+			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
+					    TPS("FirstBQnoWake"));
+			rcu_nocb_unlock_irqrestore(rdp, flags);
+		}
+	}
+	return true; // Callback already enqueued.
+}
+
+/*
+ * Awaken the no-CBs grace-period kthread if needed, either due to it
+ * legitimately being asleep or due to overload conditions.
+ *
+ * If warranted, also wake up the kthread servicing this CPUs queues.
+ */
+static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
+				 unsigned long flags)
+				 __releases(rdp->nocb_lock)
+{
+	unsigned long cur_gp_seq;
+	unsigned long j;
+	long len;
+	struct task_struct *t;
+
+	// If we are being polled or there is no kthread, just leave.
+	t = READ_ONCE(rdp->nocb_gp_kthread);
+	if (rcu_nocb_poll || !t) {
+		rcu_nocb_unlock_irqrestore(rdp, flags);
+		trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
+				    TPS("WakeNotPoll"));
+		return;
+	}
+	// Need to actually to a wakeup.
+	len = rcu_segcblist_n_cbs(&rdp->cblist);
+	if (was_alldone) {
+		rdp->qlen_last_fqs_check = len;
+		if (!irqs_disabled_flags(flags)) {
+			/* ... if queue was empty ... */
+			rcu_nocb_unlock_irqrestore(rdp, flags);
+			wake_nocb_gp(rdp, false);
+			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
+					    TPS("WakeEmpty"));
+		} else {
+			rcu_nocb_unlock_irqrestore(rdp, flags);
+			wake_nocb_gp_defer(rdp, RCU_NOCB_WAKE,
+					   TPS("WakeEmptyIsDeferred"));
+		}
+	} else if (len > rdp->qlen_last_fqs_check + qhimark) {
+		/* ... or if many callbacks queued. */
+		rdp->qlen_last_fqs_check = len;
+		j = jiffies;
+		if (j != rdp->nocb_gp_adv_time &&
+		    rcu_segcblist_nextgp(&rdp->cblist, &cur_gp_seq) &&
+		    rcu_seq_done(&rdp->mynode->gp_seq, cur_gp_seq)) {
+			rcu_advance_cbs_nowake(rdp->mynode, rdp);
+			rdp->nocb_gp_adv_time = j;
+		}
+		smp_mb(); /* Enqueue before timer_pending(). */
+		if ((rdp->nocb_cb_sleep ||
+		     !rcu_segcblist_ready_cbs(&rdp->cblist)) &&
+		    !timer_pending(&rdp->nocb_timer)) {
+			rcu_nocb_unlock_irqrestore(rdp, flags);
+			wake_nocb_gp_defer(rdp, RCU_NOCB_WAKE_FORCE,
+					   TPS("WakeOvfIsDeferred"));
+		} else {
+			rcu_nocb_unlock_irqrestore(rdp, flags);
+			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WakeNot"));
+		}
+	} else {
+		rcu_nocb_unlock_irqrestore(rdp, flags);
+		trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WakeNot"));
+	}
+}
+
+static int nocb_gp_toggle_rdp(struct rcu_data *rdp,
+			       bool *wake_state)
+{
+	struct rcu_segcblist *cblist = &rdp->cblist;
+	unsigned long flags;
+	int ret;
+
+	rcu_nocb_lock_irqsave(rdp, flags);
+	if (rcu_segcblist_test_flags(cblist, SEGCBLIST_OFFLOADED) &&
+	    !rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_GP)) {
+		/*
+		 * Offloading. Set our flag and notify the offload worker.
+		 * We will handle this rdp until it ever gets de-offloaded.
+		 */
+		rcu_segcblist_set_flags(cblist, SEGCBLIST_KTHREAD_GP);
+		if (rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_CB))
+			*wake_state = true;
+		ret = 1;
+	} else if (!rcu_segcblist_test_flags(cblist, SEGCBLIST_OFFLOADED) &&
+		   rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_GP)) {
+		/*
+		 * De-offloading. Clear our flag and notify the de-offload worker.
+		 * We will ignore this rdp until it ever gets re-offloaded.
+		 */
+		rcu_segcblist_clear_flags(cblist, SEGCBLIST_KTHREAD_GP);
+		if (!rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_CB))
+			*wake_state = true;
+		ret = 0;
+	} else {
+		WARN_ON_ONCE(1);
+		ret = -1;
+	}
+
+	rcu_nocb_unlock_irqrestore(rdp, flags);
+
+	return ret;
+}
+
+static void nocb_gp_sleep(struct rcu_data *my_rdp, int cpu)
+{
+	trace_rcu_nocb_wake(rcu_state.name, cpu, TPS("Sleep"));
+	swait_event_interruptible_exclusive(my_rdp->nocb_gp_wq,
+					!READ_ONCE(my_rdp->nocb_gp_sleep));
+	trace_rcu_nocb_wake(rcu_state.name, cpu, TPS("EndSleep"));
+}
+
+/*
+ * No-CBs GP kthreads come here to wait for additional callbacks to show up
+ * or for grace periods to end.
+ */
+static void nocb_gp_wait(struct rcu_data *my_rdp)
+{
+	bool bypass = false;
+	long bypass_ncbs;
+	int __maybe_unused cpu = my_rdp->cpu;
+	unsigned long cur_gp_seq;
+	unsigned long flags;
+	bool gotcbs = false;
+	unsigned long j = jiffies;
+	bool needwait_gp = false; // This prevents actual uninitialized use.
+	bool needwake;
+	bool needwake_gp;
+	struct rcu_data *rdp, *rdp_toggling = NULL;
+	struct rcu_node *rnp;
+	unsigned long wait_gp_seq = 0; // Suppress "use uninitialized" warning.
+	bool wasempty = false;
+
+	/*
+	 * Each pass through the following loop checks for CBs and for the
+	 * nearest grace period (if any) to wait for next.  The CB kthreads
+	 * and the global grace-period kthread are awakened if needed.
+	 */
+	WARN_ON_ONCE(my_rdp->nocb_gp_rdp != my_rdp);
+	/*
+	 * An rcu_data structure is removed from the list after its
+	 * CPU is de-offloaded and added to the list before that CPU is
+	 * (re-)offloaded.  If the following loop happens to be referencing
+	 * that rcu_data structure during the time that the corresponding
+	 * CPU is de-offloaded and then immediately re-offloaded, this
+	 * loop's rdp pointer will be carried to the end of the list by
+	 * the resulting pair of list operations.  This can cause the loop
+	 * to skip over some of the rcu_data structures that were supposed
+	 * to have been scanned.  Fortunately a new iteration through the
+	 * entire loop is forced after a given CPU's rcu_data structure
+	 * is added to the list, so the skipped-over rcu_data structures
+	 * won't be ignored for long.
+	 */
+	list_for_each_entry(rdp, &my_rdp->nocb_head_rdp, nocb_entry_rdp) {
+		trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("Check"));
+		rcu_nocb_lock_irqsave(rdp, flags);
+		lockdep_assert_held(&rdp->nocb_lock);
+		bypass_ncbs = rcu_cblist_n_cbs(&rdp->nocb_bypass);
+		if (bypass_ncbs &&
+		    (time_after(j, READ_ONCE(rdp->nocb_bypass_first) + 1) ||
+		     bypass_ncbs > 2 * qhimark)) {
+			// Bypass full or old, so flush it.
+			(void)rcu_nocb_try_flush_bypass(rdp, j);
+			bypass_ncbs = rcu_cblist_n_cbs(&rdp->nocb_bypass);
+		} else if (!bypass_ncbs && rcu_segcblist_empty(&rdp->cblist)) {
+			rcu_nocb_unlock_irqrestore(rdp, flags);
+			continue; /* No callbacks here, try next. */
+		}
+		if (bypass_ncbs) {
+			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
+					    TPS("Bypass"));
+			bypass = true;
+		}
+		rnp = rdp->mynode;
+
+		// Advance callbacks if helpful and low contention.
+		needwake_gp = false;
+		if (!rcu_segcblist_restempty(&rdp->cblist,
+					     RCU_NEXT_READY_TAIL) ||
+		    (rcu_segcblist_nextgp(&rdp->cblist, &cur_gp_seq) &&
+		     rcu_seq_done(&rnp->gp_seq, cur_gp_seq))) {
+			raw_spin_lock_rcu_node(rnp); /* irqs disabled. */
+			needwake_gp = rcu_advance_cbs(rnp, rdp);
+			wasempty = rcu_segcblist_restempty(&rdp->cblist,
+							   RCU_NEXT_READY_TAIL);
+			raw_spin_unlock_rcu_node(rnp); /* irqs disabled. */
+		}
+		// Need to wait on some grace period?
+		WARN_ON_ONCE(wasempty &&
+			     !rcu_segcblist_restempty(&rdp->cblist,
+						      RCU_NEXT_READY_TAIL));
+		if (rcu_segcblist_nextgp(&rdp->cblist, &cur_gp_seq)) {
+			if (!needwait_gp ||
+			    ULONG_CMP_LT(cur_gp_seq, wait_gp_seq))
+				wait_gp_seq = cur_gp_seq;
+			needwait_gp = true;
+			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
+					    TPS("NeedWaitGP"));
+		}
+		if (rcu_segcblist_ready_cbs(&rdp->cblist)) {
+			needwake = rdp->nocb_cb_sleep;
+			WRITE_ONCE(rdp->nocb_cb_sleep, false);
+			smp_mb(); /* CB invocation -after- GP end. */
+		} else {
+			needwake = false;
+		}
+		rcu_nocb_unlock_irqrestore(rdp, flags);
+		if (needwake) {
+			swake_up_one(&rdp->nocb_cb_wq);
+			gotcbs = true;
+		}
+		if (needwake_gp)
+			rcu_gp_kthread_wake();
+	}
+
+	my_rdp->nocb_gp_bypass = bypass;
+	my_rdp->nocb_gp_gp = needwait_gp;
+	my_rdp->nocb_gp_seq = needwait_gp ? wait_gp_seq : 0;
+
+	if (bypass && !rcu_nocb_poll) {
+		// At least one child with non-empty ->nocb_bypass, so set
+		// timer in order to avoid stranding its callbacks.
+		wake_nocb_gp_defer(my_rdp, RCU_NOCB_WAKE_BYPASS,
+				   TPS("WakeBypassIsDeferred"));
+	}
+	if (rcu_nocb_poll) {
+		/* Polling, so trace if first poll in the series. */
+		if (gotcbs)
+			trace_rcu_nocb_wake(rcu_state.name, cpu, TPS("Poll"));
+		if (list_empty(&my_rdp->nocb_head_rdp)) {
+			raw_spin_lock_irqsave(&my_rdp->nocb_gp_lock, flags);
+			if (!my_rdp->nocb_toggling_rdp)
+				WRITE_ONCE(my_rdp->nocb_gp_sleep, true);
+			raw_spin_unlock_irqrestore(&my_rdp->nocb_gp_lock, flags);
+			/* Wait for any offloading rdp */
+			nocb_gp_sleep(my_rdp, cpu);
+		} else {
+			schedule_timeout_idle(1);
+		}
+	} else if (!needwait_gp) {
+		/* Wait for callbacks to appear. */
+		nocb_gp_sleep(my_rdp, cpu);
+	} else {
+		rnp = my_rdp->mynode;
+		trace_rcu_this_gp(rnp, my_rdp, wait_gp_seq, TPS("StartWait"));
+		swait_event_interruptible_exclusive(
+			rnp->nocb_gp_wq[rcu_seq_ctr(wait_gp_seq) & 0x1],
+			rcu_seq_done(&rnp->gp_seq, wait_gp_seq) ||
+			!READ_ONCE(my_rdp->nocb_gp_sleep));
+		trace_rcu_this_gp(rnp, my_rdp, wait_gp_seq, TPS("EndWait"));
+	}
+
+	if (!rcu_nocb_poll) {
+		raw_spin_lock_irqsave(&my_rdp->nocb_gp_lock, flags);
+		// (De-)queue an rdp to/from the group if its nocb state is changing
+		rdp_toggling = my_rdp->nocb_toggling_rdp;
+		if (rdp_toggling)
+			my_rdp->nocb_toggling_rdp = NULL;
+
+		if (my_rdp->nocb_defer_wakeup > RCU_NOCB_WAKE_NOT) {
+			WRITE_ONCE(my_rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_NOT);
+			del_timer(&my_rdp->nocb_timer);
+		}
+		WRITE_ONCE(my_rdp->nocb_gp_sleep, true);
+		raw_spin_unlock_irqrestore(&my_rdp->nocb_gp_lock, flags);
+	} else {
+		rdp_toggling = READ_ONCE(my_rdp->nocb_toggling_rdp);
+		if (rdp_toggling) {
+			/*
+			 * Paranoid locking to make sure nocb_toggling_rdp is well
+			 * reset *before* we (re)set SEGCBLIST_KTHREAD_GP or we could
+			 * race with another round of nocb toggling for this rdp.
+			 * Nocb locking should prevent from that already but we stick
+			 * to paranoia, especially in rare path.
+			 */
+			raw_spin_lock_irqsave(&my_rdp->nocb_gp_lock, flags);
+			my_rdp->nocb_toggling_rdp = NULL;
+			raw_spin_unlock_irqrestore(&my_rdp->nocb_gp_lock, flags);
+		}
+	}
+
+	if (rdp_toggling) {
+		bool wake_state = false;
+		int ret;
+
+		ret = nocb_gp_toggle_rdp(rdp_toggling, &wake_state);
+		if (ret == 1)
+			list_add_tail(&rdp_toggling->nocb_entry_rdp, &my_rdp->nocb_head_rdp);
+		else if (ret == 0)
+			list_del(&rdp_toggling->nocb_entry_rdp);
+		if (wake_state)
+			swake_up_one(&rdp_toggling->nocb_state_wq);
+	}
+
+	my_rdp->nocb_gp_seq = -1;
+	WARN_ON(signal_pending(current));
+}
+
+/*
+ * No-CBs grace-period-wait kthread.  There is one of these per group
+ * of CPUs, but only once at least one CPU in that group has come online
+ * at least once since boot.  This kthread checks for newly posted
+ * callbacks from any of the CPUs it is responsible for, waits for a
+ * grace period, then awakens all of the rcu_nocb_cb_kthread() instances
+ * that then have callback-invocation work to do.
+ */
+static int rcu_nocb_gp_kthread(void *arg)
+{
+	struct rcu_data *rdp = arg;
+
+	for (;;) {
+		WRITE_ONCE(rdp->nocb_gp_loops, rdp->nocb_gp_loops + 1);
+		nocb_gp_wait(rdp);
+		cond_resched_tasks_rcu_qs();
+	}
+	return 0;
+}
+
+static inline bool nocb_cb_can_run(struct rcu_data *rdp)
+{
+	u8 flags = SEGCBLIST_OFFLOADED | SEGCBLIST_KTHREAD_CB;
+
+	return rcu_segcblist_test_flags(&rdp->cblist, flags);
+}
+
+static inline bool nocb_cb_wait_cond(struct rcu_data *rdp)
+{
+	return nocb_cb_can_run(rdp) && !READ_ONCE(rdp->nocb_cb_sleep);
+}
+
+/*
+ * Invoke any ready callbacks from the corresponding no-CBs CPU,
+ * then, if there are no more, wait for more to appear.
+ */
+static void nocb_cb_wait(struct rcu_data *rdp)
+{
+	struct rcu_segcblist *cblist = &rdp->cblist;
+	unsigned long cur_gp_seq;
+	unsigned long flags;
+	bool needwake_state = false;
+	bool needwake_gp = false;
+	bool can_sleep = true;
+	struct rcu_node *rnp = rdp->mynode;
+
+	do {
+		swait_event_interruptible_exclusive(rdp->nocb_cb_wq,
+						    nocb_cb_wait_cond(rdp));
+
+		// VVV Ensure CB invocation follows _sleep test.
+		if (smp_load_acquire(&rdp->nocb_cb_sleep)) { // ^^^
+			WARN_ON(signal_pending(current));
+			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WokeEmpty"));
+		}
+	} while (!nocb_cb_can_run(rdp));
+
+
+	local_irq_save(flags);
+	rcu_momentary_dyntick_idle();
+	local_irq_restore(flags);
+	/*
+	 * Disable BH to provide the expected environment.  Also, when
+	 * transitioning to/from NOCB mode, a self-requeuing callback might
+	 * be invoked from softirq.  A short grace period could cause both
+	 * instances of this callback would execute concurrently.
+	 */
+	local_bh_disable();
+	rcu_do_batch(rdp);
+	local_bh_enable();
+	lockdep_assert_irqs_enabled();
+	rcu_nocb_lock_irqsave(rdp, flags);
+	if (rcu_segcblist_nextgp(cblist, &cur_gp_seq) &&
+	    rcu_seq_done(&rnp->gp_seq, cur_gp_seq) &&
+	    raw_spin_trylock_rcu_node(rnp)) { /* irqs already disabled. */
+		needwake_gp = rcu_advance_cbs(rdp->mynode, rdp);
+		raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */
+	}
+
+	if (rcu_segcblist_test_flags(cblist, SEGCBLIST_OFFLOADED)) {
+		if (!rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_CB)) {
+			rcu_segcblist_set_flags(cblist, SEGCBLIST_KTHREAD_CB);
+			if (rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_GP))
+				needwake_state = true;
+		}
+		if (rcu_segcblist_ready_cbs(cblist))
+			can_sleep = false;
+	} else {
+		/*
+		 * De-offloading. Clear our flag and notify the de-offload worker.
+		 * We won't touch the callbacks and keep sleeping until we ever
+		 * get re-offloaded.
+		 */
+		WARN_ON_ONCE(!rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_CB));
+		rcu_segcblist_clear_flags(cblist, SEGCBLIST_KTHREAD_CB);
+		if (!rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_GP))
+			needwake_state = true;
+	}
+
+	WRITE_ONCE(rdp->nocb_cb_sleep, can_sleep);
+
+	if (rdp->nocb_cb_sleep)
+		trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("CBSleep"));
+
+	rcu_nocb_unlock_irqrestore(rdp, flags);
+	if (needwake_gp)
+		rcu_gp_kthread_wake();
+
+	if (needwake_state)
+		swake_up_one(&rdp->nocb_state_wq);
+}
+
+/*
+ * Per-rcu_data kthread, but only for no-CBs CPUs.  Repeatedly invoke
+ * nocb_cb_wait() to do the dirty work.
+ */
+static int rcu_nocb_cb_kthread(void *arg)
+{
+	struct rcu_data *rdp = arg;
+
+	// Each pass through this loop does one callback batch, and,
+	// if there are no more ready callbacks, waits for them.
+	for (;;) {
+		nocb_cb_wait(rdp);
+		cond_resched_tasks_rcu_qs();
+	}
+	return 0;
+}
+
+/* Is a deferred wakeup of rcu_nocb_kthread() required? */
+static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp, int level)
+{
+	return READ_ONCE(rdp->nocb_defer_wakeup) >= level;
+}
+
+/* Do a deferred wakeup of rcu_nocb_kthread(). */
+static bool do_nocb_deferred_wakeup_common(struct rcu_data *rdp_gp,
+					   struct rcu_data *rdp, int level,
+					   unsigned long flags)
+	__releases(rdp_gp->nocb_gp_lock)
+{
+	int ndw;
+	int ret;
+
+	if (!rcu_nocb_need_deferred_wakeup(rdp_gp, level)) {
+		raw_spin_unlock_irqrestore(&rdp_gp->nocb_gp_lock, flags);
+		return false;
+	}
+
+	ndw = rdp_gp->nocb_defer_wakeup;
+	ret = __wake_nocb_gp(rdp_gp, rdp, ndw == RCU_NOCB_WAKE_FORCE, flags);
+	trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("DeferredWake"));
+
+	return ret;
+}
+
+/* Do a deferred wakeup of rcu_nocb_kthread() from a timer handler. */
+static void do_nocb_deferred_wakeup_timer(struct timer_list *t)
+{
+	unsigned long flags;
+	struct rcu_data *rdp = from_timer(rdp, t, nocb_timer);
+
+	WARN_ON_ONCE(rdp->nocb_gp_rdp != rdp);
+	trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("Timer"));
+
+	raw_spin_lock_irqsave(&rdp->nocb_gp_lock, flags);
+	smp_mb__after_spinlock(); /* Timer expire before wakeup. */
+	do_nocb_deferred_wakeup_common(rdp, rdp, RCU_NOCB_WAKE_BYPASS, flags);
+}
+
+/*
+ * Do a deferred wakeup of rcu_nocb_kthread() from fastpath.
+ * This means we do an inexact common-case check.  Note that if
+ * we miss, ->nocb_timer will eventually clean things up.
+ */
+static bool do_nocb_deferred_wakeup(struct rcu_data *rdp)
+{
+	unsigned long flags;
+	struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
+
+	if (!rdp_gp || !rcu_nocb_need_deferred_wakeup(rdp_gp, RCU_NOCB_WAKE))
+		return false;
+
+	raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags);
+	return do_nocb_deferred_wakeup_common(rdp_gp, rdp, RCU_NOCB_WAKE, flags);
+}
+
+void rcu_nocb_flush_deferred_wakeup(void)
+{
+	do_nocb_deferred_wakeup(this_cpu_ptr(&rcu_data));
+}
+EXPORT_SYMBOL_GPL(rcu_nocb_flush_deferred_wakeup);
+
+static int rdp_offload_toggle(struct rcu_data *rdp,
+			       bool offload, unsigned long flags)
+	__releases(rdp->nocb_lock)
+{
+	struct rcu_segcblist *cblist = &rdp->cblist;
+	struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
+	bool wake_gp = false;
+
+	rcu_segcblist_offload(cblist, offload);
+
+	if (rdp->nocb_cb_sleep)
+		rdp->nocb_cb_sleep = false;
+	rcu_nocb_unlock_irqrestore(rdp, flags);
+
+	/*
+	 * Ignore former value of nocb_cb_sleep and force wake up as it could
+	 * have been spuriously set to false already.
+	 */
+	swake_up_one(&rdp->nocb_cb_wq);
+
+	raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags);
+	// Queue this rdp for add/del to/from the list to iterate on rcuog
+	WRITE_ONCE(rdp_gp->nocb_toggling_rdp, rdp);
+	if (rdp_gp->nocb_gp_sleep) {
+		rdp_gp->nocb_gp_sleep = false;
+		wake_gp = true;
+	}
+	raw_spin_unlock_irqrestore(&rdp_gp->nocb_gp_lock, flags);
+
+	return wake_gp;
+}
+
+static long rcu_nocb_rdp_deoffload(void *arg)
+{
+	struct rcu_data *rdp = arg;
+	struct rcu_segcblist *cblist = &rdp->cblist;
+	unsigned long flags;
+	int wake_gp;
+	struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
+
+	/*
+	 * rcu_nocb_rdp_deoffload() may be called directly if
+	 * rcuog/o[p] spawn failed, because at this time the rdp->cpu
+	 * is not online yet.
+	 */
+	WARN_ON_ONCE((rdp->cpu != raw_smp_processor_id()) && cpu_online(rdp->cpu));
+
+	pr_info("De-offloading %d\n", rdp->cpu);
+
+	rcu_nocb_lock_irqsave(rdp, flags);
+	/*
+	 * Flush once and for all now. This suffices because we are
+	 * running on the target CPU holding ->nocb_lock (thus having
+	 * interrupts disabled), and because rdp_offload_toggle()
+	 * invokes rcu_segcblist_offload(), which clears SEGCBLIST_OFFLOADED.
+	 * Thus future calls to rcu_segcblist_completely_offloaded() will
+	 * return false, which means that future calls to rcu_nocb_try_bypass()
+	 * will refuse to put anything into the bypass.
+	 */
+	WARN_ON_ONCE(!rcu_nocb_flush_bypass(rdp, NULL, jiffies));
+	/*
+	 * Start with invoking rcu_core() early. This way if the current thread
+	 * happens to preempt an ongoing call to rcu_core() in the middle,
+	 * leaving some work dismissed because rcu_core() still thinks the rdp is
+	 * completely offloaded, we are guaranteed a nearby future instance of
+	 * rcu_core() to catch up.
+	 */
+	rcu_segcblist_set_flags(cblist, SEGCBLIST_RCU_CORE);
+	invoke_rcu_core();
+	wake_gp = rdp_offload_toggle(rdp, false, flags);
+
+	mutex_lock(&rdp_gp->nocb_gp_kthread_mutex);
+	if (rdp_gp->nocb_gp_kthread) {
+		if (wake_gp)
+			wake_up_process(rdp_gp->nocb_gp_kthread);
+
+		/*
+		 * If rcuo[p] kthread spawn failed, directly remove SEGCBLIST_KTHREAD_CB.
+		 * Just wait SEGCBLIST_KTHREAD_GP to be cleared by rcuog.
+		 */
+		if (!rdp->nocb_cb_kthread) {
+			rcu_nocb_lock_irqsave(rdp, flags);
+			rcu_segcblist_clear_flags(&rdp->cblist, SEGCBLIST_KTHREAD_CB);
+			rcu_nocb_unlock_irqrestore(rdp, flags);
+		}
+
+		swait_event_exclusive(rdp->nocb_state_wq,
+					!rcu_segcblist_test_flags(cblist,
+					  SEGCBLIST_KTHREAD_CB | SEGCBLIST_KTHREAD_GP));
+	} else {
+		/*
+		 * No kthread to clear the flags for us or remove the rdp from the nocb list
+		 * to iterate. Do it here instead. Locking doesn't look stricly necessary
+		 * but we stick to paranoia in this rare path.
+		 */
+		rcu_nocb_lock_irqsave(rdp, flags);
+		rcu_segcblist_clear_flags(&rdp->cblist,
+				SEGCBLIST_KTHREAD_CB | SEGCBLIST_KTHREAD_GP);
+		rcu_nocb_unlock_irqrestore(rdp, flags);
+
+		list_del(&rdp->nocb_entry_rdp);
+	}
+	mutex_unlock(&rdp_gp->nocb_gp_kthread_mutex);
+
+	/*
+	 * Lock one last time to acquire latest callback updates from kthreads
+	 * so we can later handle callbacks locally without locking.
+	 */
+	rcu_nocb_lock_irqsave(rdp, flags);
+	/*
+	 * Theoretically we could clear SEGCBLIST_LOCKING after the nocb
+	 * lock is released but how about being paranoid for once?
+	 */
+	rcu_segcblist_clear_flags(cblist, SEGCBLIST_LOCKING);
+	/*
+	 * Without SEGCBLIST_LOCKING, we can't use
+	 * rcu_nocb_unlock_irqrestore() anymore.
+	 */
+	raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags);
+
+	/* Sanity check */
+	WARN_ON_ONCE(rcu_cblist_n_cbs(&rdp->nocb_bypass));
+
+
+	return 0;
+}
+
+int rcu_nocb_cpu_deoffload(int cpu)
+{
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+	int ret = 0;
+
+	cpus_read_lock();
+	mutex_lock(&rcu_state.barrier_mutex);
+	if (rcu_rdp_is_offloaded(rdp)) {
+		if (cpu_online(cpu)) {
+			ret = work_on_cpu(cpu, rcu_nocb_rdp_deoffload, rdp);
+			if (!ret)
+				cpumask_clear_cpu(cpu, rcu_nocb_mask);
+		} else {
+			pr_info("NOCB: Cannot CB-deoffload offline CPU %d\n", rdp->cpu);
+			ret = -EINVAL;
+		}
+	}
+	mutex_unlock(&rcu_state.barrier_mutex);
+	cpus_read_unlock();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rcu_nocb_cpu_deoffload);
+
+static long rcu_nocb_rdp_offload(void *arg)
+{
+	struct rcu_data *rdp = arg;
+	struct rcu_segcblist *cblist = &rdp->cblist;
+	unsigned long flags;
+	int wake_gp;
+	struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
+
+	WARN_ON_ONCE(rdp->cpu != raw_smp_processor_id());
+	/*
+	 * For now we only support re-offload, ie: the rdp must have been
+	 * offloaded on boot first.
+	 */
+	if (!rdp->nocb_gp_rdp)
+		return -EINVAL;
+
+	if (WARN_ON_ONCE(!rdp_gp->nocb_gp_kthread))
+		return -EINVAL;
+
+	pr_info("Offloading %d\n", rdp->cpu);
+
+	/*
+	 * Can't use rcu_nocb_lock_irqsave() before SEGCBLIST_LOCKING
+	 * is set.
+	 */
+	raw_spin_lock_irqsave(&rdp->nocb_lock, flags);
+
+	/*
+	 * We didn't take the nocb lock while working on the
+	 * rdp->cblist with SEGCBLIST_LOCKING cleared (pure softirq/rcuc mode).
+	 * Every modifications that have been done previously on
+	 * rdp->cblist must be visible remotely by the nocb kthreads
+	 * upon wake up after reading the cblist flags.
+	 *
+	 * The layout against nocb_lock enforces that ordering:
+	 *
+	 *  __rcu_nocb_rdp_offload()   nocb_cb_wait()/nocb_gp_wait()
+	 * -------------------------   ----------------------------
+	 *      WRITE callbacks           rcu_nocb_lock()
+	 *      rcu_nocb_lock()           READ flags
+	 *      WRITE flags               READ callbacks
+	 *      rcu_nocb_unlock()         rcu_nocb_unlock()
+	 */
+	wake_gp = rdp_offload_toggle(rdp, true, flags);
+	if (wake_gp)
+		wake_up_process(rdp_gp->nocb_gp_kthread);
+	swait_event_exclusive(rdp->nocb_state_wq,
+			      rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_CB) &&
+			      rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_GP));
+
+	/*
+	 * All kthreads are ready to work, we can finally relieve rcu_core() and
+	 * enable nocb bypass.
+	 */
+	rcu_nocb_lock_irqsave(rdp, flags);
+	rcu_segcblist_clear_flags(cblist, SEGCBLIST_RCU_CORE);
+	rcu_nocb_unlock_irqrestore(rdp, flags);
+
+	return 0;
+}
+
+int rcu_nocb_cpu_offload(int cpu)
+{
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+	int ret = 0;
+
+	cpus_read_lock();
+	mutex_lock(&rcu_state.barrier_mutex);
+	if (!rcu_rdp_is_offloaded(rdp)) {
+		if (cpu_online(cpu)) {
+			ret = work_on_cpu(cpu, rcu_nocb_rdp_offload, rdp);
+			if (!ret)
+				cpumask_set_cpu(cpu, rcu_nocb_mask);
+		} else {
+			pr_info("NOCB: Cannot CB-offload offline CPU %d\n", rdp->cpu);
+			ret = -EINVAL;
+		}
+	}
+	mutex_unlock(&rcu_state.barrier_mutex);
+	cpus_read_unlock();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rcu_nocb_cpu_offload);
+
+void __init rcu_init_nohz(void)
+{
+	int cpu;
+	bool need_rcu_nocb_mask = false;
+	bool offload_all = false;
+	struct rcu_data *rdp;
+
+#if defined(CONFIG_RCU_NOCB_CPU_DEFAULT_ALL)
+	if (!rcu_state.nocb_is_setup) {
+		need_rcu_nocb_mask = true;
+		offload_all = true;
+	}
+#endif /* #if defined(CONFIG_RCU_NOCB_CPU_DEFAULT_ALL) */
+
+#if defined(CONFIG_NO_HZ_FULL)
+	if (tick_nohz_full_running && !cpumask_empty(tick_nohz_full_mask)) {
+		need_rcu_nocb_mask = true;
+		offload_all = false; /* NO_HZ_FULL has its own mask. */
+	}
+#endif /* #if defined(CONFIG_NO_HZ_FULL) */
+
+	if (need_rcu_nocb_mask) {
+		if (!cpumask_available(rcu_nocb_mask)) {
+			if (!zalloc_cpumask_var(&rcu_nocb_mask, GFP_KERNEL)) {
+				pr_info("rcu_nocb_mask allocation failed, callback offloading disabled.\n");
+				return;
+			}
+		}
+		rcu_state.nocb_is_setup = true;
+	}
+
+	if (!rcu_state.nocb_is_setup)
+		return;
+
+#if defined(CONFIG_NO_HZ_FULL)
+	if (tick_nohz_full_running)
+		cpumask_or(rcu_nocb_mask, rcu_nocb_mask, tick_nohz_full_mask);
+#endif /* #if defined(CONFIG_NO_HZ_FULL) */
+
+	if (offload_all)
+		cpumask_setall(rcu_nocb_mask);
+
+	if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
+		pr_info("\tNote: kernel parameter 'rcu_nocbs=', 'nohz_full', or 'isolcpus=' contains nonexistent CPUs.\n");
+		cpumask_and(rcu_nocb_mask, cpu_possible_mask,
+			    rcu_nocb_mask);
+	}
+	if (cpumask_empty(rcu_nocb_mask))
+		pr_info("\tOffload RCU callbacks from CPUs: (none).\n");
+	else
+		pr_info("\tOffload RCU callbacks from CPUs: %*pbl.\n",
+			cpumask_pr_args(rcu_nocb_mask));
+	if (rcu_nocb_poll)
+		pr_info("\tPoll for callbacks from no-CBs CPUs.\n");
+
+	for_each_cpu(cpu, rcu_nocb_mask) {
+		rdp = per_cpu_ptr(&rcu_data, cpu);
+		if (rcu_segcblist_empty(&rdp->cblist))
+			rcu_segcblist_init(&rdp->cblist);
+		rcu_segcblist_offload(&rdp->cblist, true);
+		rcu_segcblist_set_flags(&rdp->cblist, SEGCBLIST_KTHREAD_CB | SEGCBLIST_KTHREAD_GP);
+		rcu_segcblist_clear_flags(&rdp->cblist, SEGCBLIST_RCU_CORE);
+	}
+	rcu_organize_nocb_kthreads();
+}
+
+/* Initialize per-rcu_data variables for no-CBs CPUs. */
+static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp)
+{
+	init_swait_queue_head(&rdp->nocb_cb_wq);
+	init_swait_queue_head(&rdp->nocb_gp_wq);
+	init_swait_queue_head(&rdp->nocb_state_wq);
+	raw_spin_lock_init(&rdp->nocb_lock);
+	raw_spin_lock_init(&rdp->nocb_bypass_lock);
+	raw_spin_lock_init(&rdp->nocb_gp_lock);
+	timer_setup(&rdp->nocb_timer, do_nocb_deferred_wakeup_timer, 0);
+	rcu_cblist_init(&rdp->nocb_bypass);
+	mutex_init(&rdp->nocb_gp_kthread_mutex);
+}
+
+/*
+ * If the specified CPU is a no-CBs CPU that does not already have its
+ * rcuo CB kthread, spawn it.  Additionally, if the rcuo GP kthread
+ * for this CPU's group has not yet been created, spawn it as well.
+ */
+static void rcu_spawn_cpu_nocb_kthread(int cpu)
+{
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+	struct rcu_data *rdp_gp;
+	struct task_struct *t;
+	struct sched_param sp;
+
+	if (!rcu_scheduler_fully_active || !rcu_state.nocb_is_setup)
+		return;
+
+	/* If there already is an rcuo kthread, then nothing to do. */
+	if (rdp->nocb_cb_kthread)
+		return;
+
+	/* If we didn't spawn the GP kthread first, reorganize! */
+	sp.sched_priority = kthread_prio;
+	rdp_gp = rdp->nocb_gp_rdp;
+	mutex_lock(&rdp_gp->nocb_gp_kthread_mutex);
+	if (!rdp_gp->nocb_gp_kthread) {
+		t = kthread_run(rcu_nocb_gp_kthread, rdp_gp,
+				"rcuog/%d", rdp_gp->cpu);
+		if (WARN_ONCE(IS_ERR(t), "%s: Could not start rcuo GP kthread, OOM is now expected behavior\n", __func__)) {
+			mutex_unlock(&rdp_gp->nocb_gp_kthread_mutex);
+			goto end;
+		}
+		WRITE_ONCE(rdp_gp->nocb_gp_kthread, t);
+		if (kthread_prio)
+			sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
+	}
+	mutex_unlock(&rdp_gp->nocb_gp_kthread_mutex);
+
+	/* Spawn the kthread for this CPU. */
+	t = kthread_run(rcu_nocb_cb_kthread, rdp,
+			"rcuo%c/%d", rcu_state.abbr, cpu);
+	if (WARN_ONCE(IS_ERR(t), "%s: Could not start rcuo CB kthread, OOM is now expected behavior\n", __func__))
+		goto end;
+
+	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_CB_BOOST) && kthread_prio)
+		sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
+
+	WRITE_ONCE(rdp->nocb_cb_kthread, t);
+	WRITE_ONCE(rdp->nocb_gp_kthread, rdp_gp->nocb_gp_kthread);
+	return;
+end:
+	mutex_lock(&rcu_state.barrier_mutex);
+	if (rcu_rdp_is_offloaded(rdp)) {
+		rcu_nocb_rdp_deoffload(rdp);
+		cpumask_clear_cpu(cpu, rcu_nocb_mask);
+	}
+	mutex_unlock(&rcu_state.barrier_mutex);
+}
+
+/* How many CB CPU IDs per GP kthread?  Default of -1 for sqrt(nr_cpu_ids). */
+static int rcu_nocb_gp_stride = -1;
+module_param(rcu_nocb_gp_stride, int, 0444);
+
+/*
+ * Initialize GP-CB relationships for all no-CBs CPU.
+ */
+static void __init rcu_organize_nocb_kthreads(void)
+{
+	int cpu;
+	bool firsttime = true;
+	bool gotnocbs = false;
+	bool gotnocbscbs = true;
+	int ls = rcu_nocb_gp_stride;
+	int nl = 0;  /* Next GP kthread. */
+	struct rcu_data *rdp;
+	struct rcu_data *rdp_gp = NULL;  /* Suppress misguided gcc warn. */
+
+	if (!cpumask_available(rcu_nocb_mask))
+		return;
+	if (ls == -1) {
+		ls = nr_cpu_ids / int_sqrt(nr_cpu_ids);
+		rcu_nocb_gp_stride = ls;
+	}
+
+	/*
+	 * Each pass through this loop sets up one rcu_data structure.
+	 * Should the corresponding CPU come online in the future, then
+	 * we will spawn the needed set of rcu_nocb_kthread() kthreads.
+	 */
+	for_each_possible_cpu(cpu) {
+		rdp = per_cpu_ptr(&rcu_data, cpu);
+		if (rdp->cpu >= nl) {
+			/* New GP kthread, set up for CBs & next GP. */
+			gotnocbs = true;
+			nl = DIV_ROUND_UP(rdp->cpu + 1, ls) * ls;
+			rdp_gp = rdp;
+			INIT_LIST_HEAD(&rdp->nocb_head_rdp);
+			if (dump_tree) {
+				if (!firsttime)
+					pr_cont("%s\n", gotnocbscbs
+							? "" : " (self only)");
+				gotnocbscbs = false;
+				firsttime = false;
+				pr_alert("%s: No-CB GP kthread CPU %d:",
+					 __func__, cpu);
+			}
+		} else {
+			/* Another CB kthread, link to previous GP kthread. */
+			gotnocbscbs = true;
+			if (dump_tree)
+				pr_cont(" %d", cpu);
+		}
+		rdp->nocb_gp_rdp = rdp_gp;
+		if (cpumask_test_cpu(cpu, rcu_nocb_mask))
+			list_add_tail(&rdp->nocb_entry_rdp, &rdp_gp->nocb_head_rdp);
+	}
+	if (gotnocbs && dump_tree)
+		pr_cont("%s\n", gotnocbscbs ? "" : " (self only)");
+}
+
+/*
+ * Bind the current task to the offloaded CPUs.  If there are no offloaded
+ * CPUs, leave the task unbound.  Splat if the bind attempt fails.
+ */
+void rcu_bind_current_to_nocb(void)
+{
+	if (cpumask_available(rcu_nocb_mask) && !cpumask_empty(rcu_nocb_mask))
+		WARN_ON(sched_setaffinity(current->pid, rcu_nocb_mask));
+}
+EXPORT_SYMBOL_GPL(rcu_bind_current_to_nocb);
+
+// The ->on_cpu field is available only in CONFIG_SMP=y, so...
+#ifdef CONFIG_SMP
+static char *show_rcu_should_be_on_cpu(struct task_struct *tsp)
+{
+	return tsp && task_is_running(tsp) && !tsp->on_cpu ? "!" : "";
+}
+#else // #ifdef CONFIG_SMP
+static char *show_rcu_should_be_on_cpu(struct task_struct *tsp)
+{
+	return "";
+}
+#endif // #else #ifdef CONFIG_SMP
+
+/*
+ * Dump out nocb grace-period kthread state for the specified rcu_data
+ * structure.
+ */
+static void show_rcu_nocb_gp_state(struct rcu_data *rdp)
+{
+	struct rcu_node *rnp = rdp->mynode;
+
+	pr_info("nocb GP %d %c%c%c%c%c %c[%c%c] %c%c:%ld rnp %d:%d %lu %c CPU %d%s\n",
+		rdp->cpu,
+		"kK"[!!rdp->nocb_gp_kthread],
+		"lL"[raw_spin_is_locked(&rdp->nocb_gp_lock)],
+		"dD"[!!rdp->nocb_defer_wakeup],
+		"tT"[timer_pending(&rdp->nocb_timer)],
+		"sS"[!!rdp->nocb_gp_sleep],
+		".W"[swait_active(&rdp->nocb_gp_wq)],
+		".W"[swait_active(&rnp->nocb_gp_wq[0])],
+		".W"[swait_active(&rnp->nocb_gp_wq[1])],
+		".B"[!!rdp->nocb_gp_bypass],
+		".G"[!!rdp->nocb_gp_gp],
+		(long)rdp->nocb_gp_seq,
+		rnp->grplo, rnp->grphi, READ_ONCE(rdp->nocb_gp_loops),
+		rdp->nocb_gp_kthread ? task_state_to_char(rdp->nocb_gp_kthread) : '.',
+		rdp->nocb_gp_kthread ? (int)task_cpu(rdp->nocb_gp_kthread) : -1,
+		show_rcu_should_be_on_cpu(rdp->nocb_gp_kthread));
+}
+
+/* Dump out nocb kthread state for the specified rcu_data structure. */
+static void show_rcu_nocb_state(struct rcu_data *rdp)
+{
+	char bufw[20];
+	char bufr[20];
+	struct rcu_data *nocb_next_rdp;
+	struct rcu_segcblist *rsclp = &rdp->cblist;
+	bool waslocked;
+	bool wassleep;
+
+	if (rdp->nocb_gp_rdp == rdp)
+		show_rcu_nocb_gp_state(rdp);
+
+	nocb_next_rdp = list_next_or_null_rcu(&rdp->nocb_gp_rdp->nocb_head_rdp,
+					      &rdp->nocb_entry_rdp,
+					      typeof(*rdp),
+					      nocb_entry_rdp);
+
+	sprintf(bufw, "%ld", rsclp->gp_seq[RCU_WAIT_TAIL]);
+	sprintf(bufr, "%ld", rsclp->gp_seq[RCU_NEXT_READY_TAIL]);
+	pr_info("   CB %d^%d->%d %c%c%c%c%c%c F%ld L%ld C%d %c%c%s%c%s%c%c q%ld %c CPU %d%s\n",
+		rdp->cpu, rdp->nocb_gp_rdp->cpu,
+		nocb_next_rdp ? nocb_next_rdp->cpu : -1,
+		"kK"[!!rdp->nocb_cb_kthread],
+		"bB"[raw_spin_is_locked(&rdp->nocb_bypass_lock)],
+		"cC"[!!atomic_read(&rdp->nocb_lock_contended)],
+		"lL"[raw_spin_is_locked(&rdp->nocb_lock)],
+		"sS"[!!rdp->nocb_cb_sleep],
+		".W"[swait_active(&rdp->nocb_cb_wq)],
+		jiffies - rdp->nocb_bypass_first,
+		jiffies - rdp->nocb_nobypass_last,
+		rdp->nocb_nobypass_count,
+		".D"[rcu_segcblist_ready_cbs(rsclp)],
+		".W"[!rcu_segcblist_segempty(rsclp, RCU_WAIT_TAIL)],
+		rcu_segcblist_segempty(rsclp, RCU_WAIT_TAIL) ? "" : bufw,
+		".R"[!rcu_segcblist_segempty(rsclp, RCU_NEXT_READY_TAIL)],
+		rcu_segcblist_segempty(rsclp, RCU_NEXT_READY_TAIL) ? "" : bufr,
+		".N"[!rcu_segcblist_segempty(rsclp, RCU_NEXT_TAIL)],
+		".B"[!!rcu_cblist_n_cbs(&rdp->nocb_bypass)],
+		rcu_segcblist_n_cbs(&rdp->cblist),
+		rdp->nocb_cb_kthread ? task_state_to_char(rdp->nocb_cb_kthread) : '.',
+		rdp->nocb_cb_kthread ? (int)task_cpu(rdp->nocb_cb_kthread) : -1,
+		show_rcu_should_be_on_cpu(rdp->nocb_cb_kthread));
+
+	/* It is OK for GP kthreads to have GP state. */
+	if (rdp->nocb_gp_rdp == rdp)
+		return;
+
+	waslocked = raw_spin_is_locked(&rdp->nocb_gp_lock);
+	wassleep = swait_active(&rdp->nocb_gp_wq);
+	if (!rdp->nocb_gp_sleep && !waslocked && !wassleep)
+		return;  /* Nothing untoward. */
+
+	pr_info("   nocb GP activity on CB-only CPU!!! %c%c%c %c\n",
+		"lL"[waslocked],
+		"dD"[!!rdp->nocb_defer_wakeup],
+		"sS"[!!rdp->nocb_gp_sleep],
+		".W"[wassleep]);
+}
+
+#else /* #ifdef CONFIG_RCU_NOCB_CPU */
+
+static inline int rcu_lockdep_is_held_nocb(struct rcu_data *rdp)
+{
+	return 0;
+}
+
+static inline bool rcu_current_is_nocb_kthread(struct rcu_data *rdp)
+{
+	return false;
+}
+
+/* No ->nocb_lock to acquire.  */
+static void rcu_nocb_lock(struct rcu_data *rdp)
+{
+}
+
+/* No ->nocb_lock to release.  */
+static void rcu_nocb_unlock(struct rcu_data *rdp)
+{
+}
+
+/* No ->nocb_lock to release.  */
+static void rcu_nocb_unlock_irqrestore(struct rcu_data *rdp,
+				       unsigned long flags)
+{
+	local_irq_restore(flags);
+}
+
+/* Lockdep check that ->cblist may be safely accessed. */
+static void rcu_lockdep_assert_cblist_protected(struct rcu_data *rdp)
+{
+	lockdep_assert_irqs_disabled();
+}
+
+static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq)
+{
+}
+
+static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp)
+{
+	return NULL;
+}
+
+static void rcu_init_one_nocb(struct rcu_node *rnp)
+{
+}
+
+static bool rcu_nocb_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
+				  unsigned long j)
+{
+	return true;
+}
+
+static bool rcu_nocb_try_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
+				bool *was_alldone, unsigned long flags)
+{
+	return false;
+}
+
+static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_empty,
+				 unsigned long flags)
+{
+	WARN_ON_ONCE(1);  /* Should be dead code! */
+}
+
+static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp)
+{
+}
+
+static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp, int level)
+{
+	return false;
+}
+
+static bool do_nocb_deferred_wakeup(struct rcu_data *rdp)
+{
+	return false;
+}
+
+static void rcu_spawn_cpu_nocb_kthread(int cpu)
+{
+}
+
+static void show_rcu_nocb_state(struct rcu_data *rdp)
+{
+}
+
+#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
new file mode 100644
index 000000000..044026abf
--- /dev/null
+++ b/kernel/rcu/tree_plugin.h
@@ -0,0 +1,1304 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Read-Copy Update mechanism for mutual exclusion (tree-based version)
+ * Internal non-public definitions that provide either classic
+ * or preemptible semantics.
+ *
+ * Copyright Red Hat, 2009
+ * Copyright IBM Corporation, 2009
+ *
+ * Author: Ingo Molnar <mingo@elte.hu>
+ *	   Paul E. McKenney <paulmck@linux.ibm.com>
+ */
+
+#include "../locking/rtmutex_common.h"
+
+static bool rcu_rdp_is_offloaded(struct rcu_data *rdp)
+{
+	/*
+	 * In order to read the offloaded state of an rdp in a safe
+	 * and stable way and prevent from its value to be changed
+	 * under us, we must either hold the barrier mutex, the cpu
+	 * hotplug lock (read or write) or the nocb lock. Local
+	 * non-preemptible reads are also safe. NOCB kthreads and
+	 * timers have their own means of synchronization against the
+	 * offloaded state updaters.
+	 */
+	RCU_LOCKDEP_WARN(
+		!(lockdep_is_held(&rcu_state.barrier_mutex) ||
+		  (IS_ENABLED(CONFIG_HOTPLUG_CPU) && lockdep_is_cpus_held()) ||
+		  rcu_lockdep_is_held_nocb(rdp) ||
+		  (rdp == this_cpu_ptr(&rcu_data) &&
+		   !(IS_ENABLED(CONFIG_PREEMPT_COUNT) && preemptible())) ||
+		  rcu_current_is_nocb_kthread(rdp)),
+		"Unsafe read of RCU_NOCB offloaded state"
+	);
+
+	return rcu_segcblist_is_offloaded(&rdp->cblist);
+}
+
+/*
+ * Check the RCU kernel configuration parameters and print informative
+ * messages about anything out of the ordinary.
+ */
+static void __init rcu_bootup_announce_oddness(void)
+{
+	if (IS_ENABLED(CONFIG_RCU_TRACE))
+		pr_info("\tRCU event tracing is enabled.\n");
+	if ((IS_ENABLED(CONFIG_64BIT) && RCU_FANOUT != 64) ||
+	    (!IS_ENABLED(CONFIG_64BIT) && RCU_FANOUT != 32))
+		pr_info("\tCONFIG_RCU_FANOUT set to non-default value of %d.\n",
+			RCU_FANOUT);
+	if (rcu_fanout_exact)
+		pr_info("\tHierarchical RCU autobalancing is disabled.\n");
+	if (IS_ENABLED(CONFIG_PROVE_RCU))
+		pr_info("\tRCU lockdep checking is enabled.\n");
+	if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD))
+		pr_info("\tRCU strict (and thus non-scalable) grace periods are enabled.\n");
+	if (RCU_NUM_LVLS >= 4)
+		pr_info("\tFour(or more)-level hierarchy is enabled.\n");
+	if (RCU_FANOUT_LEAF != 16)
+		pr_info("\tBuild-time adjustment of leaf fanout to %d.\n",
+			RCU_FANOUT_LEAF);
+	if (rcu_fanout_leaf != RCU_FANOUT_LEAF)
+		pr_info("\tBoot-time adjustment of leaf fanout to %d.\n",
+			rcu_fanout_leaf);
+	if (nr_cpu_ids != NR_CPUS)
+		pr_info("\tRCU restricting CPUs from NR_CPUS=%d to nr_cpu_ids=%u.\n", NR_CPUS, nr_cpu_ids);
+#ifdef CONFIG_RCU_BOOST
+	pr_info("\tRCU priority boosting: priority %d delay %d ms.\n",
+		kthread_prio, CONFIG_RCU_BOOST_DELAY);
+#endif
+	if (blimit != DEFAULT_RCU_BLIMIT)
+		pr_info("\tBoot-time adjustment of callback invocation limit to %ld.\n", blimit);
+	if (qhimark != DEFAULT_RCU_QHIMARK)
+		pr_info("\tBoot-time adjustment of callback high-water mark to %ld.\n", qhimark);
+	if (qlowmark != DEFAULT_RCU_QLOMARK)
+		pr_info("\tBoot-time adjustment of callback low-water mark to %ld.\n", qlowmark);
+	if (qovld != DEFAULT_RCU_QOVLD)
+		pr_info("\tBoot-time adjustment of callback overload level to %ld.\n", qovld);
+	if (jiffies_till_first_fqs != ULONG_MAX)
+		pr_info("\tBoot-time adjustment of first FQS scan delay to %ld jiffies.\n", jiffies_till_first_fqs);
+	if (jiffies_till_next_fqs != ULONG_MAX)
+		pr_info("\tBoot-time adjustment of subsequent FQS scan delay to %ld jiffies.\n", jiffies_till_next_fqs);
+	if (jiffies_till_sched_qs != ULONG_MAX)
+		pr_info("\tBoot-time adjustment of scheduler-enlistment delay to %ld jiffies.\n", jiffies_till_sched_qs);
+	if (rcu_kick_kthreads)
+		pr_info("\tKick kthreads if too-long grace period.\n");
+	if (IS_ENABLED(CONFIG_DEBUG_OBJECTS_RCU_HEAD))
+		pr_info("\tRCU callback double-/use-after-free debug is enabled.\n");
+	if (gp_preinit_delay)
+		pr_info("\tRCU debug GP pre-init slowdown %d jiffies.\n", gp_preinit_delay);
+	if (gp_init_delay)
+		pr_info("\tRCU debug GP init slowdown %d jiffies.\n", gp_init_delay);
+	if (gp_cleanup_delay)
+		pr_info("\tRCU debug GP cleanup slowdown %d jiffies.\n", gp_cleanup_delay);
+	if (!use_softirq)
+		pr_info("\tRCU_SOFTIRQ processing moved to rcuc kthreads.\n");
+	if (IS_ENABLED(CONFIG_RCU_EQS_DEBUG))
+		pr_info("\tRCU debug extended QS entry/exit.\n");
+	rcupdate_announce_bootup_oddness();
+}
+
+#ifdef CONFIG_PREEMPT_RCU
+
+static void rcu_report_exp_rnp(struct rcu_node *rnp, bool wake);
+static void rcu_read_unlock_special(struct task_struct *t);
+
+/*
+ * Tell them what RCU they are running.
+ */
+static void __init rcu_bootup_announce(void)
+{
+	pr_info("Preemptible hierarchical RCU implementation.\n");
+	rcu_bootup_announce_oddness();
+}
+
+/* Flags for rcu_preempt_ctxt_queue() decision table. */
+#define RCU_GP_TASKS	0x8
+#define RCU_EXP_TASKS	0x4
+#define RCU_GP_BLKD	0x2
+#define RCU_EXP_BLKD	0x1
+
+/*
+ * Queues a task preempted within an RCU-preempt read-side critical
+ * section into the appropriate location within the ->blkd_tasks list,
+ * depending on the states of any ongoing normal and expedited grace
+ * periods.  The ->gp_tasks pointer indicates which element the normal
+ * grace period is waiting on (NULL if none), and the ->exp_tasks pointer
+ * indicates which element the expedited grace period is waiting on (again,
+ * NULL if none).  If a grace period is waiting on a given element in the
+ * ->blkd_tasks list, it also waits on all subsequent elements.  Thus,
+ * adding a task to the tail of the list blocks any grace period that is
+ * already waiting on one of the elements.  In contrast, adding a task
+ * to the head of the list won't block any grace period that is already
+ * waiting on one of the elements.
+ *
+ * This queuing is imprecise, and can sometimes make an ongoing grace
+ * period wait for a task that is not strictly speaking blocking it.
+ * Given the choice, we needlessly block a normal grace period rather than
+ * blocking an expedited grace period.
+ *
+ * Note that an endless sequence of expedited grace periods still cannot
+ * indefinitely postpone a normal grace period.  Eventually, all of the
+ * fixed number of preempted tasks blocking the normal grace period that are
+ * not also blocking the expedited grace period will resume and complete
+ * their RCU read-side critical sections.  At that point, the ->gp_tasks
+ * pointer will equal the ->exp_tasks pointer, at which point the end of
+ * the corresponding expedited grace period will also be the end of the
+ * normal grace period.
+ */
+static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
+	__releases(rnp->lock) /* But leaves rrupts disabled. */
+{
+	int blkd_state = (rnp->gp_tasks ? RCU_GP_TASKS : 0) +
+			 (rnp->exp_tasks ? RCU_EXP_TASKS : 0) +
+			 (rnp->qsmask & rdp->grpmask ? RCU_GP_BLKD : 0) +
+			 (rnp->expmask & rdp->grpmask ? RCU_EXP_BLKD : 0);
+	struct task_struct *t = current;
+
+	raw_lockdep_assert_held_rcu_node(rnp);
+	WARN_ON_ONCE(rdp->mynode != rnp);
+	WARN_ON_ONCE(!rcu_is_leaf_node(rnp));
+	/* RCU better not be waiting on newly onlined CPUs! */
+	WARN_ON_ONCE(rnp->qsmaskinitnext & ~rnp->qsmaskinit & rnp->qsmask &
+		     rdp->grpmask);
+
+	/*
+	 * Decide where to queue the newly blocked task.  In theory,
+	 * this could be an if-statement.  In practice, when I tried
+	 * that, it was quite messy.
+	 */
+	switch (blkd_state) {
+	case 0:
+	case                RCU_EXP_TASKS:
+	case                RCU_EXP_TASKS + RCU_GP_BLKD:
+	case RCU_GP_TASKS:
+	case RCU_GP_TASKS + RCU_EXP_TASKS:
+
+		/*
+		 * Blocking neither GP, or first task blocking the normal
+		 * GP but not blocking the already-waiting expedited GP.
+		 * Queue at the head of the list to avoid unnecessarily
+		 * blocking the already-waiting GPs.
+		 */
+		list_add(&t->rcu_node_entry, &rnp->blkd_tasks);
+		break;
+
+	case                                              RCU_EXP_BLKD:
+	case                                RCU_GP_BLKD:
+	case                                RCU_GP_BLKD + RCU_EXP_BLKD:
+	case RCU_GP_TASKS +                               RCU_EXP_BLKD:
+	case RCU_GP_TASKS +                 RCU_GP_BLKD + RCU_EXP_BLKD:
+	case RCU_GP_TASKS + RCU_EXP_TASKS + RCU_GP_BLKD + RCU_EXP_BLKD:
+
+		/*
+		 * First task arriving that blocks either GP, or first task
+		 * arriving that blocks the expedited GP (with the normal
+		 * GP already waiting), or a task arriving that blocks
+		 * both GPs with both GPs already waiting.  Queue at the
+		 * tail of the list to avoid any GP waiting on any of the
+		 * already queued tasks that are not blocking it.
+		 */
+		list_add_tail(&t->rcu_node_entry, &rnp->blkd_tasks);
+		break;
+
+	case                RCU_EXP_TASKS +               RCU_EXP_BLKD:
+	case                RCU_EXP_TASKS + RCU_GP_BLKD + RCU_EXP_BLKD:
+	case RCU_GP_TASKS + RCU_EXP_TASKS +               RCU_EXP_BLKD:
+
+		/*
+		 * Second or subsequent task blocking the expedited GP.
+		 * The task either does not block the normal GP, or is the
+		 * first task blocking the normal GP.  Queue just after
+		 * the first task blocking the expedited GP.
+		 */
+		list_add(&t->rcu_node_entry, rnp->exp_tasks);
+		break;
+
+	case RCU_GP_TASKS +                 RCU_GP_BLKD:
+	case RCU_GP_TASKS + RCU_EXP_TASKS + RCU_GP_BLKD:
+
+		/*
+		 * Second or subsequent task blocking the normal GP.
+		 * The task does not block the expedited GP. Queue just
+		 * after the first task blocking the normal GP.
+		 */
+		list_add(&t->rcu_node_entry, rnp->gp_tasks);
+		break;
+
+	default:
+
+		/* Yet another exercise in excessive paranoia. */
+		WARN_ON_ONCE(1);
+		break;
+	}
+
+	/*
+	 * We have now queued the task.  If it was the first one to
+	 * block either grace period, update the ->gp_tasks and/or
+	 * ->exp_tasks pointers, respectively, to reference the newly
+	 * blocked tasks.
+	 */
+	if (!rnp->gp_tasks && (blkd_state & RCU_GP_BLKD)) {
+		WRITE_ONCE(rnp->gp_tasks, &t->rcu_node_entry);
+		WARN_ON_ONCE(rnp->completedqs == rnp->gp_seq);
+	}
+	if (!rnp->exp_tasks && (blkd_state & RCU_EXP_BLKD))
+		WRITE_ONCE(rnp->exp_tasks, &t->rcu_node_entry);
+	WARN_ON_ONCE(!(blkd_state & RCU_GP_BLKD) !=
+		     !(rnp->qsmask & rdp->grpmask));
+	WARN_ON_ONCE(!(blkd_state & RCU_EXP_BLKD) !=
+		     !(rnp->expmask & rdp->grpmask));
+	raw_spin_unlock_rcu_node(rnp); /* interrupts remain disabled. */
+
+	/*
+	 * Report the quiescent state for the expedited GP.  This expedited
+	 * GP should not be able to end until we report, so there should be
+	 * no need to check for a subsequent expedited GP.  (Though we are
+	 * still in a quiescent state in any case.)
+	 *
+	 * Interrupts are disabled, so ->cpu_no_qs.b.exp cannot change.
+	 */
+	if (blkd_state & RCU_EXP_BLKD && rdp->cpu_no_qs.b.exp)
+		rcu_report_exp_rdp(rdp);
+	else
+		WARN_ON_ONCE(rdp->cpu_no_qs.b.exp);
+}
+
+/*
+ * Record a preemptible-RCU quiescent state for the specified CPU.
+ * Note that this does not necessarily mean that the task currently running
+ * on the CPU is in a quiescent state:  Instead, it means that the current
+ * grace period need not wait on any RCU read-side critical section that
+ * starts later on this CPU.  It also means that if the current task is
+ * in an RCU read-side critical section, it has already added itself to
+ * some leaf rcu_node structure's ->blkd_tasks list.  In addition to the
+ * current task, there might be any number of other tasks blocked while
+ * in an RCU read-side critical section.
+ *
+ * Unlike non-preemptible-RCU, quiescent state reports for expedited
+ * grace periods are handled separately via deferred quiescent states
+ * and context switch events.
+ *
+ * Callers to this function must disable preemption.
+ */
+static void rcu_qs(void)
+{
+	RCU_LOCKDEP_WARN(preemptible(), "rcu_qs() invoked with preemption enabled!!!\n");
+	if (__this_cpu_read(rcu_data.cpu_no_qs.b.norm)) {
+		trace_rcu_grace_period(TPS("rcu_preempt"),
+				       __this_cpu_read(rcu_data.gp_seq),
+				       TPS("cpuqs"));
+		__this_cpu_write(rcu_data.cpu_no_qs.b.norm, false);
+		barrier(); /* Coordinate with rcu_flavor_sched_clock_irq(). */
+		WRITE_ONCE(current->rcu_read_unlock_special.b.need_qs, false);
+	}
+}
+
+/*
+ * We have entered the scheduler, and the current task might soon be
+ * context-switched away from.  If this task is in an RCU read-side
+ * critical section, we will no longer be able to rely on the CPU to
+ * record that fact, so we enqueue the task on the blkd_tasks list.
+ * The task will dequeue itself when it exits the outermost enclosing
+ * RCU read-side critical section.  Therefore, the current grace period
+ * cannot be permitted to complete until the blkd_tasks list entries
+ * predating the current grace period drain, in other words, until
+ * rnp->gp_tasks becomes NULL.
+ *
+ * Caller must disable interrupts.
+ */
+void rcu_note_context_switch(bool preempt)
+{
+	struct task_struct *t = current;
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
+	struct rcu_node *rnp;
+
+	trace_rcu_utilization(TPS("Start context switch"));
+	lockdep_assert_irqs_disabled();
+	WARN_ONCE(!preempt && rcu_preempt_depth() > 0, "Voluntary context switch within RCU read-side critical section!");
+	if (rcu_preempt_depth() > 0 &&
+	    !t->rcu_read_unlock_special.b.blocked) {
+
+		/* Possibly blocking in an RCU read-side critical section. */
+		rnp = rdp->mynode;
+		raw_spin_lock_rcu_node(rnp);
+		t->rcu_read_unlock_special.b.blocked = true;
+		t->rcu_blocked_node = rnp;
+
+		/*
+		 * Verify the CPU's sanity, trace the preemption, and
+		 * then queue the task as required based on the states
+		 * of any ongoing and expedited grace periods.
+		 */
+		WARN_ON_ONCE(!rcu_rdp_cpu_online(rdp));
+		WARN_ON_ONCE(!list_empty(&t->rcu_node_entry));
+		trace_rcu_preempt_task(rcu_state.name,
+				       t->pid,
+				       (rnp->qsmask & rdp->grpmask)
+				       ? rnp->gp_seq
+				       : rcu_seq_snap(&rnp->gp_seq));
+		rcu_preempt_ctxt_queue(rnp, rdp);
+	} else {
+		rcu_preempt_deferred_qs(t);
+	}
+
+	/*
+	 * Either we were not in an RCU read-side critical section to
+	 * begin with, or we have now recorded that critical section
+	 * globally.  Either way, we can now note a quiescent state
+	 * for this CPU.  Again, if we were in an RCU read-side critical
+	 * section, and if that critical section was blocking the current
+	 * grace period, then the fact that the task has been enqueued
+	 * means that we continue to block the current grace period.
+	 */
+	rcu_qs();
+	if (rdp->cpu_no_qs.b.exp)
+		rcu_report_exp_rdp(rdp);
+	rcu_tasks_qs(current, preempt);
+	trace_rcu_utilization(TPS("End context switch"));
+}
+EXPORT_SYMBOL_GPL(rcu_note_context_switch);
+
+/*
+ * Check for preempted RCU readers blocking the current grace period
+ * for the specified rcu_node structure.  If the caller needs a reliable
+ * answer, it must hold the rcu_node's ->lock.
+ */
+static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp)
+{
+	return READ_ONCE(rnp->gp_tasks) != NULL;
+}
+
+/* limit value for ->rcu_read_lock_nesting. */
+#define RCU_NEST_PMAX (INT_MAX / 2)
+
+static void rcu_preempt_read_enter(void)
+{
+	WRITE_ONCE(current->rcu_read_lock_nesting, READ_ONCE(current->rcu_read_lock_nesting) + 1);
+}
+
+static int rcu_preempt_read_exit(void)
+{
+	int ret = READ_ONCE(current->rcu_read_lock_nesting) - 1;
+
+	WRITE_ONCE(current->rcu_read_lock_nesting, ret);
+	return ret;
+}
+
+static void rcu_preempt_depth_set(int val)
+{
+	WRITE_ONCE(current->rcu_read_lock_nesting, val);
+}
+
+/*
+ * Preemptible RCU implementation for rcu_read_lock().
+ * Just increment ->rcu_read_lock_nesting, shared state will be updated
+ * if we block.
+ */
+void __rcu_read_lock(void)
+{
+	rcu_preempt_read_enter();
+	if (IS_ENABLED(CONFIG_PROVE_LOCKING))
+		WARN_ON_ONCE(rcu_preempt_depth() > RCU_NEST_PMAX);
+	if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD) && rcu_state.gp_kthread)
+		WRITE_ONCE(current->rcu_read_unlock_special.b.need_qs, true);
+	barrier();  /* critical section after entry code. */
+}
+EXPORT_SYMBOL_GPL(__rcu_read_lock);
+
+/*
+ * Preemptible RCU implementation for rcu_read_unlock().
+ * Decrement ->rcu_read_lock_nesting.  If the result is zero (outermost
+ * rcu_read_unlock()) and ->rcu_read_unlock_special is non-zero, then
+ * invoke rcu_read_unlock_special() to clean up after a context switch
+ * in an RCU read-side critical section and other special cases.
+ */
+void __rcu_read_unlock(void)
+{
+	struct task_struct *t = current;
+
+	barrier();  // critical section before exit code.
+	if (rcu_preempt_read_exit() == 0) {
+		barrier();  // critical-section exit before .s check.
+		if (unlikely(READ_ONCE(t->rcu_read_unlock_special.s)))
+			rcu_read_unlock_special(t);
+	}
+	if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
+		int rrln = rcu_preempt_depth();
+
+		WARN_ON_ONCE(rrln < 0 || rrln > RCU_NEST_PMAX);
+	}
+}
+EXPORT_SYMBOL_GPL(__rcu_read_unlock);
+
+/*
+ * Advance a ->blkd_tasks-list pointer to the next entry, instead
+ * returning NULL if at the end of the list.
+ */
+static struct list_head *rcu_next_node_entry(struct task_struct *t,
+					     struct rcu_node *rnp)
+{
+	struct list_head *np;
+
+	np = t->rcu_node_entry.next;
+	if (np == &rnp->blkd_tasks)
+		np = NULL;
+	return np;
+}
+
+/*
+ * Return true if the specified rcu_node structure has tasks that were
+ * preempted within an RCU read-side critical section.
+ */
+static bool rcu_preempt_has_tasks(struct rcu_node *rnp)
+{
+	return !list_empty(&rnp->blkd_tasks);
+}
+
+/*
+ * Report deferred quiescent states.  The deferral time can
+ * be quite short, for example, in the case of the call from
+ * rcu_read_unlock_special().
+ */
+static notrace void
+rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
+{
+	bool empty_exp;
+	bool empty_norm;
+	bool empty_exp_now;
+	struct list_head *np;
+	bool drop_boost_mutex = false;
+	struct rcu_data *rdp;
+	struct rcu_node *rnp;
+	union rcu_special special;
+
+	/*
+	 * If RCU core is waiting for this CPU to exit its critical section,
+	 * report the fact that it has exited.  Because irqs are disabled,
+	 * t->rcu_read_unlock_special cannot change.
+	 */
+	special = t->rcu_read_unlock_special;
+	rdp = this_cpu_ptr(&rcu_data);
+	if (!special.s && !rdp->cpu_no_qs.b.exp) {
+		local_irq_restore(flags);
+		return;
+	}
+	t->rcu_read_unlock_special.s = 0;
+	if (special.b.need_qs) {
+		if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD)) {
+			rdp->cpu_no_qs.b.norm = false;
+			rcu_report_qs_rdp(rdp);
+			udelay(rcu_unlock_delay);
+		} else {
+			rcu_qs();
+		}
+	}
+
+	/*
+	 * Respond to a request by an expedited grace period for a
+	 * quiescent state from this CPU.  Note that requests from
+	 * tasks are handled when removing the task from the
+	 * blocked-tasks list below.
+	 */
+	if (rdp->cpu_no_qs.b.exp)
+		rcu_report_exp_rdp(rdp);
+
+	/* Clean up if blocked during RCU read-side critical section. */
+	if (special.b.blocked) {
+
+		/*
+		 * Remove this task from the list it blocked on.  The task
+		 * now remains queued on the rcu_node corresponding to the
+		 * CPU it first blocked on, so there is no longer any need
+		 * to loop.  Retain a WARN_ON_ONCE() out of sheer paranoia.
+		 */
+		rnp = t->rcu_blocked_node;
+		raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
+		WARN_ON_ONCE(rnp != t->rcu_blocked_node);
+		WARN_ON_ONCE(!rcu_is_leaf_node(rnp));
+		empty_norm = !rcu_preempt_blocked_readers_cgp(rnp);
+		WARN_ON_ONCE(rnp->completedqs == rnp->gp_seq &&
+			     (!empty_norm || rnp->qsmask));
+		empty_exp = sync_rcu_exp_done(rnp);
+		smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */
+		np = rcu_next_node_entry(t, rnp);
+		list_del_init(&t->rcu_node_entry);
+		t->rcu_blocked_node = NULL;
+		trace_rcu_unlock_preempted_task(TPS("rcu_preempt"),
+						rnp->gp_seq, t->pid);
+		if (&t->rcu_node_entry == rnp->gp_tasks)
+			WRITE_ONCE(rnp->gp_tasks, np);
+		if (&t->rcu_node_entry == rnp->exp_tasks)
+			WRITE_ONCE(rnp->exp_tasks, np);
+		if (IS_ENABLED(CONFIG_RCU_BOOST)) {
+			/* Snapshot ->boost_mtx ownership w/rnp->lock held. */
+			drop_boost_mutex = rt_mutex_owner(&rnp->boost_mtx.rtmutex) == t;
+			if (&t->rcu_node_entry == rnp->boost_tasks)
+				WRITE_ONCE(rnp->boost_tasks, np);
+		}
+
+		/*
+		 * If this was the last task on the current list, and if
+		 * we aren't waiting on any CPUs, report the quiescent state.
+		 * Note that rcu_report_unblock_qs_rnp() releases rnp->lock,
+		 * so we must take a snapshot of the expedited state.
+		 */
+		empty_exp_now = sync_rcu_exp_done(rnp);
+		if (!empty_norm && !rcu_preempt_blocked_readers_cgp(rnp)) {
+			trace_rcu_quiescent_state_report(TPS("preempt_rcu"),
+							 rnp->gp_seq,
+							 0, rnp->qsmask,
+							 rnp->level,
+							 rnp->grplo,
+							 rnp->grphi,
+							 !!rnp->gp_tasks);
+			rcu_report_unblock_qs_rnp(rnp, flags);
+		} else {
+			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		}
+
+		/*
+		 * If this was the last task on the expedited lists,
+		 * then we need to report up the rcu_node hierarchy.
+		 */
+		if (!empty_exp && empty_exp_now)
+			rcu_report_exp_rnp(rnp, true);
+
+		/* Unboost if we were boosted. */
+		if (IS_ENABLED(CONFIG_RCU_BOOST) && drop_boost_mutex)
+			rt_mutex_futex_unlock(&rnp->boost_mtx.rtmutex);
+	} else {
+		local_irq_restore(flags);
+	}
+}
+
+/*
+ * Is a deferred quiescent-state pending, and are we also not in
+ * an RCU read-side critical section?  It is the caller's responsibility
+ * to ensure it is otherwise safe to report any deferred quiescent
+ * states.  The reason for this is that it is safe to report a
+ * quiescent state during context switch even though preemption
+ * is disabled.  This function cannot be expected to understand these
+ * nuances, so the caller must handle them.
+ */
+static notrace bool rcu_preempt_need_deferred_qs(struct task_struct *t)
+{
+	return (__this_cpu_read(rcu_data.cpu_no_qs.b.exp) ||
+		READ_ONCE(t->rcu_read_unlock_special.s)) &&
+	       rcu_preempt_depth() == 0;
+}
+
+/*
+ * Report a deferred quiescent state if needed and safe to do so.
+ * As with rcu_preempt_need_deferred_qs(), "safe" involves only
+ * not being in an RCU read-side critical section.  The caller must
+ * evaluate safety in terms of interrupt, softirq, and preemption
+ * disabling.
+ */
+notrace void rcu_preempt_deferred_qs(struct task_struct *t)
+{
+	unsigned long flags;
+
+	if (!rcu_preempt_need_deferred_qs(t))
+		return;
+	local_irq_save(flags);
+	rcu_preempt_deferred_qs_irqrestore(t, flags);
+}
+
+/*
+ * Minimal handler to give the scheduler a chance to re-evaluate.
+ */
+static void rcu_preempt_deferred_qs_handler(struct irq_work *iwp)
+{
+	struct rcu_data *rdp;
+
+	rdp = container_of(iwp, struct rcu_data, defer_qs_iw);
+	rdp->defer_qs_iw_pending = false;
+}
+
+/*
+ * Handle special cases during rcu_read_unlock(), such as needing to
+ * notify RCU core processing or task having blocked during the RCU
+ * read-side critical section.
+ */
+static void rcu_read_unlock_special(struct task_struct *t)
+{
+	unsigned long flags;
+	bool irqs_were_disabled;
+	bool preempt_bh_were_disabled =
+			!!(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK));
+
+	/* NMI handlers cannot block and cannot safely manipulate state. */
+	if (in_nmi())
+		return;
+
+	local_irq_save(flags);
+	irqs_were_disabled = irqs_disabled_flags(flags);
+	if (preempt_bh_were_disabled || irqs_were_disabled) {
+		bool expboost; // Expedited GP in flight or possible boosting.
+		struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
+		struct rcu_node *rnp = rdp->mynode;
+
+		expboost = (t->rcu_blocked_node && READ_ONCE(t->rcu_blocked_node->exp_tasks)) ||
+			   (rdp->grpmask & READ_ONCE(rnp->expmask)) ||
+			   (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD) &&
+			   ((rdp->grpmask & READ_ONCE(rnp->qsmask)) || t->rcu_blocked_node)) ||
+			   (IS_ENABLED(CONFIG_RCU_BOOST) && irqs_were_disabled &&
+			    t->rcu_blocked_node);
+		// Need to defer quiescent state until everything is enabled.
+		if (use_softirq && (in_hardirq() || (expboost && !irqs_were_disabled))) {
+			// Using softirq, safe to awaken, and either the
+			// wakeup is free or there is either an expedited
+			// GP in flight or a potential need to deboost.
+			raise_softirq_irqoff(RCU_SOFTIRQ);
+		} else {
+			// Enabling BH or preempt does reschedule, so...
+			// Also if no expediting and no possible deboosting,
+			// slow is OK.  Plus nohz_full CPUs eventually get
+			// tick enabled.
+			set_tsk_need_resched(current);
+			set_preempt_need_resched();
+			if (IS_ENABLED(CONFIG_IRQ_WORK) && irqs_were_disabled &&
+			    expboost && !rdp->defer_qs_iw_pending && cpu_online(rdp->cpu)) {
+				// Get scheduler to re-evaluate and call hooks.
+				// If !IRQ_WORK, FQS scan will eventually IPI.
+				if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD) &&
+				    IS_ENABLED(CONFIG_PREEMPT_RT))
+					rdp->defer_qs_iw = IRQ_WORK_INIT_HARD(
+								rcu_preempt_deferred_qs_handler);
+				else
+					init_irq_work(&rdp->defer_qs_iw,
+						      rcu_preempt_deferred_qs_handler);
+				rdp->defer_qs_iw_pending = true;
+				irq_work_queue_on(&rdp->defer_qs_iw, rdp->cpu);
+			}
+		}
+		local_irq_restore(flags);
+		return;
+	}
+	rcu_preempt_deferred_qs_irqrestore(t, flags);
+}
+
+/*
+ * Check that the list of blocked tasks for the newly completed grace
+ * period is in fact empty.  It is a serious bug to complete a grace
+ * period that still has RCU readers blocked!  This function must be
+ * invoked -before- updating this rnp's ->gp_seq.
+ *
+ * Also, if there are blocked tasks on the list, they automatically
+ * block the newly created grace period, so set up ->gp_tasks accordingly.
+ */
+static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp)
+{
+	struct task_struct *t;
+
+	RCU_LOCKDEP_WARN(preemptible(), "rcu_preempt_check_blocked_tasks() invoked with preemption enabled!!!\n");
+	raw_lockdep_assert_held_rcu_node(rnp);
+	if (WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)))
+		dump_blkd_tasks(rnp, 10);
+	if (rcu_preempt_has_tasks(rnp) &&
+	    (rnp->qsmaskinit || rnp->wait_blkd_tasks)) {
+		WRITE_ONCE(rnp->gp_tasks, rnp->blkd_tasks.next);
+		t = container_of(rnp->gp_tasks, struct task_struct,
+				 rcu_node_entry);
+		trace_rcu_unlock_preempted_task(TPS("rcu_preempt-GPS"),
+						rnp->gp_seq, t->pid);
+	}
+	WARN_ON_ONCE(rnp->qsmask);
+}
+
+/*
+ * Check for a quiescent state from the current CPU, including voluntary
+ * context switches for Tasks RCU.  When a task blocks, the task is
+ * recorded in the corresponding CPU's rcu_node structure, which is checked
+ * elsewhere, hence this function need only check for quiescent states
+ * related to the current CPU, not to those related to tasks.
+ */
+static void rcu_flavor_sched_clock_irq(int user)
+{
+	struct task_struct *t = current;
+
+	lockdep_assert_irqs_disabled();
+	if (rcu_preempt_depth() > 0 ||
+	    (preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK))) {
+		/* No QS, force context switch if deferred. */
+		if (rcu_preempt_need_deferred_qs(t)) {
+			set_tsk_need_resched(t);
+			set_preempt_need_resched();
+		}
+	} else if (rcu_preempt_need_deferred_qs(t)) {
+		rcu_preempt_deferred_qs(t); /* Report deferred QS. */
+		return;
+	} else if (!WARN_ON_ONCE(rcu_preempt_depth())) {
+		rcu_qs(); /* Report immediate QS. */
+		return;
+	}
+
+	/* If GP is oldish, ask for help from rcu_read_unlock_special(). */
+	if (rcu_preempt_depth() > 0 &&
+	    __this_cpu_read(rcu_data.core_needs_qs) &&
+	    __this_cpu_read(rcu_data.cpu_no_qs.b.norm) &&
+	    !t->rcu_read_unlock_special.b.need_qs &&
+	    time_after(jiffies, rcu_state.gp_start + HZ))
+		t->rcu_read_unlock_special.b.need_qs = true;
+}
+
+/*
+ * Check for a task exiting while in a preemptible-RCU read-side
+ * critical section, clean up if so.  No need to issue warnings, as
+ * debug_check_no_locks_held() already does this if lockdep is enabled.
+ * Besides, if this function does anything other than just immediately
+ * return, there was a bug of some sort.  Spewing warnings from this
+ * function is like as not to simply obscure important prior warnings.
+ */
+void exit_rcu(void)
+{
+	struct task_struct *t = current;
+
+	if (unlikely(!list_empty(&current->rcu_node_entry))) {
+		rcu_preempt_depth_set(1);
+		barrier();
+		WRITE_ONCE(t->rcu_read_unlock_special.b.blocked, true);
+	} else if (unlikely(rcu_preempt_depth())) {
+		rcu_preempt_depth_set(1);
+	} else {
+		return;
+	}
+	__rcu_read_unlock();
+	rcu_preempt_deferred_qs(current);
+}
+
+/*
+ * Dump the blocked-tasks state, but limit the list dump to the
+ * specified number of elements.
+ */
+static void
+dump_blkd_tasks(struct rcu_node *rnp, int ncheck)
+{
+	int cpu;
+	int i;
+	struct list_head *lhp;
+	struct rcu_data *rdp;
+	struct rcu_node *rnp1;
+
+	raw_lockdep_assert_held_rcu_node(rnp);
+	pr_info("%s: grp: %d-%d level: %d ->gp_seq %ld ->completedqs %ld\n",
+		__func__, rnp->grplo, rnp->grphi, rnp->level,
+		(long)READ_ONCE(rnp->gp_seq), (long)rnp->completedqs);
+	for (rnp1 = rnp; rnp1; rnp1 = rnp1->parent)
+		pr_info("%s: %d:%d ->qsmask %#lx ->qsmaskinit %#lx ->qsmaskinitnext %#lx\n",
+			__func__, rnp1->grplo, rnp1->grphi, rnp1->qsmask, rnp1->qsmaskinit, rnp1->qsmaskinitnext);
+	pr_info("%s: ->gp_tasks %p ->boost_tasks %p ->exp_tasks %p\n",
+		__func__, READ_ONCE(rnp->gp_tasks), data_race(rnp->boost_tasks),
+		READ_ONCE(rnp->exp_tasks));
+	pr_info("%s: ->blkd_tasks", __func__);
+	i = 0;
+	list_for_each(lhp, &rnp->blkd_tasks) {
+		pr_cont(" %p", lhp);
+		if (++i >= ncheck)
+			break;
+	}
+	pr_cont("\n");
+	for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++) {
+		rdp = per_cpu_ptr(&rcu_data, cpu);
+		pr_info("\t%d: %c online: %ld(%d) offline: %ld(%d)\n",
+			cpu, ".o"[rcu_rdp_cpu_online(rdp)],
+			(long)rdp->rcu_onl_gp_seq, rdp->rcu_onl_gp_flags,
+			(long)rdp->rcu_ofl_gp_seq, rdp->rcu_ofl_gp_flags);
+	}
+}
+
+#else /* #ifdef CONFIG_PREEMPT_RCU */
+
+/*
+ * If strict grace periods are enabled, and if the calling
+ * __rcu_read_unlock() marks the beginning of a quiescent state, immediately
+ * report that quiescent state and, if requested, spin for a bit.
+ */
+void rcu_read_unlock_strict(void)
+{
+	struct rcu_data *rdp;
+
+	if (irqs_disabled() || preempt_count() || !rcu_state.gp_kthread)
+		return;
+	rdp = this_cpu_ptr(&rcu_data);
+	rdp->cpu_no_qs.b.norm = false;
+	rcu_report_qs_rdp(rdp);
+	udelay(rcu_unlock_delay);
+}
+EXPORT_SYMBOL_GPL(rcu_read_unlock_strict);
+
+/*
+ * Tell them what RCU they are running.
+ */
+static void __init rcu_bootup_announce(void)
+{
+	pr_info("Hierarchical RCU implementation.\n");
+	rcu_bootup_announce_oddness();
+}
+
+/*
+ * Note a quiescent state for PREEMPTION=n.  Because we do not need to know
+ * how many quiescent states passed, just if there was at least one since
+ * the start of the grace period, this just sets a flag.  The caller must
+ * have disabled preemption.
+ */
+static void rcu_qs(void)
+{
+	RCU_LOCKDEP_WARN(preemptible(), "rcu_qs() invoked with preemption enabled!!!");
+	if (!__this_cpu_read(rcu_data.cpu_no_qs.s))
+		return;
+	trace_rcu_grace_period(TPS("rcu_sched"),
+			       __this_cpu_read(rcu_data.gp_seq), TPS("cpuqs"));
+	__this_cpu_write(rcu_data.cpu_no_qs.b.norm, false);
+	if (__this_cpu_read(rcu_data.cpu_no_qs.b.exp))
+		rcu_report_exp_rdp(this_cpu_ptr(&rcu_data));
+}
+
+/*
+ * Register an urgently needed quiescent state.  If there is an
+ * emergency, invoke rcu_momentary_dyntick_idle() to do a heavy-weight
+ * dyntick-idle quiescent state visible to other CPUs, which will in
+ * some cases serve for expedited as well as normal grace periods.
+ * Either way, register a lightweight quiescent state.
+ */
+void rcu_all_qs(void)
+{
+	unsigned long flags;
+
+	if (!raw_cpu_read(rcu_data.rcu_urgent_qs))
+		return;
+	preempt_disable();  // For CONFIG_PREEMPT_COUNT=y kernels
+	/* Load rcu_urgent_qs before other flags. */
+	if (!smp_load_acquire(this_cpu_ptr(&rcu_data.rcu_urgent_qs))) {
+		preempt_enable();
+		return;
+	}
+	this_cpu_write(rcu_data.rcu_urgent_qs, false);
+	if (unlikely(raw_cpu_read(rcu_data.rcu_need_heavy_qs))) {
+		local_irq_save(flags);
+		rcu_momentary_dyntick_idle();
+		local_irq_restore(flags);
+	}
+	rcu_qs();
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(rcu_all_qs);
+
+/*
+ * Note a PREEMPTION=n context switch. The caller must have disabled interrupts.
+ */
+void rcu_note_context_switch(bool preempt)
+{
+	trace_rcu_utilization(TPS("Start context switch"));
+	rcu_qs();
+	/* Load rcu_urgent_qs before other flags. */
+	if (!smp_load_acquire(this_cpu_ptr(&rcu_data.rcu_urgent_qs)))
+		goto out;
+	this_cpu_write(rcu_data.rcu_urgent_qs, false);
+	if (unlikely(raw_cpu_read(rcu_data.rcu_need_heavy_qs)))
+		rcu_momentary_dyntick_idle();
+out:
+	rcu_tasks_qs(current, preempt);
+	trace_rcu_utilization(TPS("End context switch"));
+}
+EXPORT_SYMBOL_GPL(rcu_note_context_switch);
+
+/*
+ * Because preemptible RCU does not exist, there are never any preempted
+ * RCU readers.
+ */
+static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp)
+{
+	return 0;
+}
+
+/*
+ * Because there is no preemptible RCU, there can be no readers blocked.
+ */
+static bool rcu_preempt_has_tasks(struct rcu_node *rnp)
+{
+	return false;
+}
+
+/*
+ * Because there is no preemptible RCU, there can be no deferred quiescent
+ * states.
+ */
+static notrace bool rcu_preempt_need_deferred_qs(struct task_struct *t)
+{
+	return false;
+}
+
+// Except that we do need to respond to a request by an expedited
+// grace period for a quiescent state from this CPU.  Note that in
+// non-preemptible kernels, there can be no context switches within RCU
+// read-side critical sections, which in turn means that the leaf rcu_node
+// structure's blocked-tasks list is always empty.  is therefore no need to
+// actually check it.  Instead, a quiescent state from this CPU suffices,
+// and this function is only called from such a quiescent state.
+notrace void rcu_preempt_deferred_qs(struct task_struct *t)
+{
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
+
+	if (READ_ONCE(rdp->cpu_no_qs.b.exp))
+		rcu_report_exp_rdp(rdp);
+}
+
+/*
+ * Because there is no preemptible RCU, there can be no readers blocked,
+ * so there is no need to check for blocked tasks.  So check only for
+ * bogus qsmask values.
+ */
+static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp)
+{
+	WARN_ON_ONCE(rnp->qsmask);
+}
+
+/*
+ * Check to see if this CPU is in a non-context-switch quiescent state,
+ * namely user mode and idle loop.
+ */
+static void rcu_flavor_sched_clock_irq(int user)
+{
+	if (user || rcu_is_cpu_rrupt_from_idle()) {
+
+		/*
+		 * Get here if this CPU took its interrupt from user
+		 * mode or from the idle loop, and if this is not a
+		 * nested interrupt.  In this case, the CPU is in
+		 * a quiescent state, so note it.
+		 *
+		 * No memory barrier is required here because rcu_qs()
+		 * references only CPU-local variables that other CPUs
+		 * neither access nor modify, at least not while the
+		 * corresponding CPU is online.
+		 */
+		rcu_qs();
+	}
+}
+
+/*
+ * Because preemptible RCU does not exist, tasks cannot possibly exit
+ * while in preemptible RCU read-side critical sections.
+ */
+void exit_rcu(void)
+{
+}
+
+/*
+ * Dump the guaranteed-empty blocked-tasks state.  Trust but verify.
+ */
+static void
+dump_blkd_tasks(struct rcu_node *rnp, int ncheck)
+{
+	WARN_ON_ONCE(!list_empty(&rnp->blkd_tasks));
+}
+
+#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+
+/*
+ * If boosting, set rcuc kthreads to realtime priority.
+ */
+static void rcu_cpu_kthread_setup(unsigned int cpu)
+{
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+#ifdef CONFIG_RCU_BOOST
+	struct sched_param sp;
+
+	sp.sched_priority = kthread_prio;
+	sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
+#endif /* #ifdef CONFIG_RCU_BOOST */
+
+	WRITE_ONCE(rdp->rcuc_activity, jiffies);
+}
+
+static bool rcu_is_callbacks_nocb_kthread(struct rcu_data *rdp)
+{
+#ifdef CONFIG_RCU_NOCB_CPU
+	return rdp->nocb_cb_kthread == current;
+#else
+	return false;
+#endif
+}
+
+/*
+ * Is the current CPU running the RCU-callbacks kthread?
+ * Caller must have preemption disabled.
+ */
+static bool rcu_is_callbacks_kthread(struct rcu_data *rdp)
+{
+	return rdp->rcu_cpu_kthread_task == current ||
+			rcu_is_callbacks_nocb_kthread(rdp);
+}
+
+#ifdef CONFIG_RCU_BOOST
+
+/*
+ * Carry out RCU priority boosting on the task indicated by ->exp_tasks
+ * or ->boost_tasks, advancing the pointer to the next task in the
+ * ->blkd_tasks list.
+ *
+ * Note that irqs must be enabled: boosting the task can block.
+ * Returns 1 if there are more tasks needing to be boosted.
+ */
+static int rcu_boost(struct rcu_node *rnp)
+{
+	unsigned long flags;
+	struct task_struct *t;
+	struct list_head *tb;
+
+	if (READ_ONCE(rnp->exp_tasks) == NULL &&
+	    READ_ONCE(rnp->boost_tasks) == NULL)
+		return 0;  /* Nothing left to boost. */
+
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+
+	/*
+	 * Recheck under the lock: all tasks in need of boosting
+	 * might exit their RCU read-side critical sections on their own.
+	 */
+	if (rnp->exp_tasks == NULL && rnp->boost_tasks == NULL) {
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		return 0;
+	}
+
+	/*
+	 * Preferentially boost tasks blocking expedited grace periods.
+	 * This cannot starve the normal grace periods because a second
+	 * expedited grace period must boost all blocked tasks, including
+	 * those blocking the pre-existing normal grace period.
+	 */
+	if (rnp->exp_tasks != NULL)
+		tb = rnp->exp_tasks;
+	else
+		tb = rnp->boost_tasks;
+
+	/*
+	 * We boost task t by manufacturing an rt_mutex that appears to
+	 * be held by task t.  We leave a pointer to that rt_mutex where
+	 * task t can find it, and task t will release the mutex when it
+	 * exits its outermost RCU read-side critical section.  Then
+	 * simply acquiring this artificial rt_mutex will boost task
+	 * t's priority.  (Thanks to tglx for suggesting this approach!)
+	 *
+	 * Note that task t must acquire rnp->lock to remove itself from
+	 * the ->blkd_tasks list, which it will do from exit() if from
+	 * nowhere else.  We therefore are guaranteed that task t will
+	 * stay around at least until we drop rnp->lock.  Note that
+	 * rnp->lock also resolves races between our priority boosting
+	 * and task t's exiting its outermost RCU read-side critical
+	 * section.
+	 */
+	t = container_of(tb, struct task_struct, rcu_node_entry);
+	rt_mutex_init_proxy_locked(&rnp->boost_mtx.rtmutex, t);
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	/* Lock only for side effect: boosts task t's priority. */
+	rt_mutex_lock(&rnp->boost_mtx);
+	rt_mutex_unlock(&rnp->boost_mtx);  /* Then keep lockdep happy. */
+	rnp->n_boosts++;
+
+	return READ_ONCE(rnp->exp_tasks) != NULL ||
+	       READ_ONCE(rnp->boost_tasks) != NULL;
+}
+
+/*
+ * Priority-boosting kthread, one per leaf rcu_node.
+ */
+static int rcu_boost_kthread(void *arg)
+{
+	struct rcu_node *rnp = (struct rcu_node *)arg;
+	int spincnt = 0;
+	int more2boost;
+
+	trace_rcu_utilization(TPS("Start boost kthread@init"));
+	for (;;) {
+		WRITE_ONCE(rnp->boost_kthread_status, RCU_KTHREAD_WAITING);
+		trace_rcu_utilization(TPS("End boost kthread@rcu_wait"));
+		rcu_wait(READ_ONCE(rnp->boost_tasks) ||
+			 READ_ONCE(rnp->exp_tasks));
+		trace_rcu_utilization(TPS("Start boost kthread@rcu_wait"));
+		WRITE_ONCE(rnp->boost_kthread_status, RCU_KTHREAD_RUNNING);
+		more2boost = rcu_boost(rnp);
+		if (more2boost)
+			spincnt++;
+		else
+			spincnt = 0;
+		if (spincnt > 10) {
+			WRITE_ONCE(rnp->boost_kthread_status, RCU_KTHREAD_YIELDING);
+			trace_rcu_utilization(TPS("End boost kthread@rcu_yield"));
+			schedule_timeout_idle(2);
+			trace_rcu_utilization(TPS("Start boost kthread@rcu_yield"));
+			spincnt = 0;
+		}
+	}
+	/* NOTREACHED */
+	trace_rcu_utilization(TPS("End boost kthread@notreached"));
+	return 0;
+}
+
+/*
+ * Check to see if it is time to start boosting RCU readers that are
+ * blocking the current grace period, and, if so, tell the per-rcu_node
+ * kthread to start boosting them.  If there is an expedited grace
+ * period in progress, it is always time to boost.
+ *
+ * The caller must hold rnp->lock, which this function releases.
+ * The ->boost_kthread_task is immortal, so we don't need to worry
+ * about it going away.
+ */
+static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
+	__releases(rnp->lock)
+{
+	raw_lockdep_assert_held_rcu_node(rnp);
+	if (!rnp->boost_kthread_task ||
+	    (!rcu_preempt_blocked_readers_cgp(rnp) && !rnp->exp_tasks)) {
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		return;
+	}
+	if (rnp->exp_tasks != NULL ||
+	    (rnp->gp_tasks != NULL &&
+	     rnp->boost_tasks == NULL &&
+	     rnp->qsmask == 0 &&
+	     (!time_after(rnp->boost_time, jiffies) || rcu_state.cbovld ||
+	      IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD)))) {
+		if (rnp->exp_tasks == NULL)
+			WRITE_ONCE(rnp->boost_tasks, rnp->gp_tasks);
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		rcu_wake_cond(rnp->boost_kthread_task,
+			      READ_ONCE(rnp->boost_kthread_status));
+	} else {
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	}
+}
+
+#define RCU_BOOST_DELAY_JIFFIES DIV_ROUND_UP(CONFIG_RCU_BOOST_DELAY * HZ, 1000)
+
+/*
+ * Do priority-boost accounting for the start of a new grace period.
+ */
+static void rcu_preempt_boost_start_gp(struct rcu_node *rnp)
+{
+	rnp->boost_time = jiffies + RCU_BOOST_DELAY_JIFFIES;
+}
+
+/*
+ * Create an RCU-boost kthread for the specified node if one does not
+ * already exist.  We only create this kthread for preemptible RCU.
+ */
+static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp)
+{
+	unsigned long flags;
+	int rnp_index = rnp - rcu_get_root();
+	struct sched_param sp;
+	struct task_struct *t;
+
+	mutex_lock(&rnp->boost_kthread_mutex);
+	if (rnp->boost_kthread_task || !rcu_scheduler_fully_active)
+		goto out;
+
+	t = kthread_create(rcu_boost_kthread, (void *)rnp,
+			   "rcub/%d", rnp_index);
+	if (WARN_ON_ONCE(IS_ERR(t)))
+		goto out;
+
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	rnp->boost_kthread_task = t;
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	sp.sched_priority = kthread_prio;
+	sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
+	wake_up_process(t); /* get to TASK_INTERRUPTIBLE quickly. */
+
+ out:
+	mutex_unlock(&rnp->boost_kthread_mutex);
+}
+
+/*
+ * Set the per-rcu_node kthread's affinity to cover all CPUs that are
+ * served by the rcu_node in question.  The CPU hotplug lock is still
+ * held, so the value of rnp->qsmaskinit will be stable.
+ *
+ * We don't include outgoingcpu in the affinity set, use -1 if there is
+ * no outgoing CPU.  If there are no CPUs left in the affinity set,
+ * this function allows the kthread to execute on any CPU.
+ */
+static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu)
+{
+	struct task_struct *t = rnp->boost_kthread_task;
+	unsigned long mask = rcu_rnp_online_cpus(rnp);
+	cpumask_var_t cm;
+	int cpu;
+
+	if (!t)
+		return;
+	if (!zalloc_cpumask_var(&cm, GFP_KERNEL))
+		return;
+	mutex_lock(&rnp->boost_kthread_mutex);
+	for_each_leaf_node_possible_cpu(rnp, cpu)
+		if ((mask & leaf_node_cpu_bit(rnp, cpu)) &&
+		    cpu != outgoingcpu)
+			cpumask_set_cpu(cpu, cm);
+	cpumask_and(cm, cm, housekeeping_cpumask(HK_TYPE_RCU));
+	if (cpumask_empty(cm)) {
+		cpumask_copy(cm, housekeeping_cpumask(HK_TYPE_RCU));
+		if (outgoingcpu >= 0)
+			cpumask_clear_cpu(outgoingcpu, cm);
+	}
+	set_cpus_allowed_ptr(t, cm);
+	mutex_unlock(&rnp->boost_kthread_mutex);
+	free_cpumask_var(cm);
+}
+
+#else /* #ifdef CONFIG_RCU_BOOST */
+
+static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
+	__releases(rnp->lock)
+{
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+}
+
+static void rcu_preempt_boost_start_gp(struct rcu_node *rnp)
+{
+}
+
+static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp)
+{
+}
+
+static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu)
+{
+}
+
+#endif /* #else #ifdef CONFIG_RCU_BOOST */
+
+/*
+ * Is this CPU a NO_HZ_FULL CPU that should ignore RCU so that the
+ * grace-period kthread will do force_quiescent_state() processing?
+ * The idea is to avoid waking up RCU core processing on such a
+ * CPU unless the grace period has extended for too long.
+ *
+ * This code relies on the fact that all NO_HZ_FULL CPUs are also
+ * RCU_NOCB_CPU CPUs.
+ */
+static bool rcu_nohz_full_cpu(void)
+{
+#ifdef CONFIG_NO_HZ_FULL
+	if (tick_nohz_full_cpu(smp_processor_id()) &&
+	    (!rcu_gp_in_progress() ||
+	     time_before(jiffies, READ_ONCE(rcu_state.gp_start) + HZ)))
+		return true;
+#endif /* #ifdef CONFIG_NO_HZ_FULL */
+	return false;
+}
+
+/*
+ * Bind the RCU grace-period kthreads to the housekeeping CPU.
+ */
+static void rcu_bind_gp_kthread(void)
+{
+	if (!tick_nohz_full_enabled())
+		return;
+	housekeeping_affine(current, HK_TYPE_RCU);
+}
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
new file mode 100644
index 000000000..7d15b5b5a
--- /dev/null
+++ b/kernel/rcu/tree_stall.h
@@ -0,0 +1,1041 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * RCU CPU stall warnings for normal RCU grace periods
+ *
+ * Copyright IBM Corporation, 2019
+ *
+ * Author: Paul E. McKenney <paulmck@linux.ibm.com>
+ */
+
+#include <linux/kvm_para.h>
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// Controlling CPU stall warnings, including delay calculation.
+
+/* panic() on RCU Stall sysctl. */
+int sysctl_panic_on_rcu_stall __read_mostly;
+int sysctl_max_rcu_stall_to_panic __read_mostly;
+
+#ifdef CONFIG_PROVE_RCU
+#define RCU_STALL_DELAY_DELTA		(5 * HZ)
+#else
+#define RCU_STALL_DELAY_DELTA		0
+#endif
+#define RCU_STALL_MIGHT_DIV		8
+#define RCU_STALL_MIGHT_MIN		(2 * HZ)
+
+int rcu_exp_jiffies_till_stall_check(void)
+{
+	int cpu_stall_timeout = READ_ONCE(rcu_exp_cpu_stall_timeout);
+	int exp_stall_delay_delta = 0;
+	int till_stall_check;
+
+	// Zero says to use rcu_cpu_stall_timeout, but in milliseconds.
+	if (!cpu_stall_timeout)
+		cpu_stall_timeout = jiffies_to_msecs(rcu_jiffies_till_stall_check());
+
+	// Limit check must be consistent with the Kconfig limits for
+	// CONFIG_RCU_EXP_CPU_STALL_TIMEOUT, so check the allowed range.
+	// The minimum clamped value is "2UL", because at least one full
+	// tick has to be guaranteed.
+	till_stall_check = clamp(msecs_to_jiffies(cpu_stall_timeout), 2UL, 21UL * HZ);
+
+	if (cpu_stall_timeout && jiffies_to_msecs(till_stall_check) != cpu_stall_timeout)
+		WRITE_ONCE(rcu_exp_cpu_stall_timeout, jiffies_to_msecs(till_stall_check));
+
+#ifdef CONFIG_PROVE_RCU
+	/* Add extra ~25% out of till_stall_check. */
+	exp_stall_delay_delta = ((till_stall_check * 25) / 100) + 1;
+#endif
+
+	return till_stall_check + exp_stall_delay_delta;
+}
+EXPORT_SYMBOL_GPL(rcu_exp_jiffies_till_stall_check);
+
+/* Limit-check stall timeouts specified at boottime and runtime. */
+int rcu_jiffies_till_stall_check(void)
+{
+	int till_stall_check = READ_ONCE(rcu_cpu_stall_timeout);
+
+	/*
+	 * Limit check must be consistent with the Kconfig limits
+	 * for CONFIG_RCU_CPU_STALL_TIMEOUT.
+	 */
+	if (till_stall_check < 3) {
+		WRITE_ONCE(rcu_cpu_stall_timeout, 3);
+		till_stall_check = 3;
+	} else if (till_stall_check > 300) {
+		WRITE_ONCE(rcu_cpu_stall_timeout, 300);
+		till_stall_check = 300;
+	}
+	return till_stall_check * HZ + RCU_STALL_DELAY_DELTA;
+}
+EXPORT_SYMBOL_GPL(rcu_jiffies_till_stall_check);
+
+/**
+ * rcu_gp_might_be_stalled - Is it likely that the grace period is stalled?
+ *
+ * Returns @true if the current grace period is sufficiently old that
+ * it is reasonable to assume that it might be stalled.  This can be
+ * useful when deciding whether to allocate memory to enable RCU-mediated
+ * freeing on the one hand or just invoking synchronize_rcu() on the other.
+ * The latter is preferable when the grace period is stalled.
+ *
+ * Note that sampling of the .gp_start and .gp_seq fields must be done
+ * carefully to avoid false positives at the beginnings and ends of
+ * grace periods.
+ */
+bool rcu_gp_might_be_stalled(void)
+{
+	unsigned long d = rcu_jiffies_till_stall_check() / RCU_STALL_MIGHT_DIV;
+	unsigned long j = jiffies;
+
+	if (d < RCU_STALL_MIGHT_MIN)
+		d = RCU_STALL_MIGHT_MIN;
+	smp_mb(); // jiffies before .gp_seq to avoid false positives.
+	if (!rcu_gp_in_progress())
+		return false;
+	// Long delays at this point avoids false positive, but a delay
+	// of ULONG_MAX/4 jiffies voids your no-false-positive warranty.
+	smp_mb(); // .gp_seq before second .gp_start
+	// And ditto here.
+	return !time_before(j, READ_ONCE(rcu_state.gp_start) + d);
+}
+
+/* Don't do RCU CPU stall warnings during long sysrq printouts. */
+void rcu_sysrq_start(void)
+{
+	if (!rcu_cpu_stall_suppress)
+		rcu_cpu_stall_suppress = 2;
+}
+
+void rcu_sysrq_end(void)
+{
+	if (rcu_cpu_stall_suppress == 2)
+		rcu_cpu_stall_suppress = 0;
+}
+
+/* Don't print RCU CPU stall warnings during a kernel panic. */
+static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr)
+{
+	rcu_cpu_stall_suppress = 1;
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block rcu_panic_block = {
+	.notifier_call = rcu_panic,
+};
+
+static int __init check_cpu_stall_init(void)
+{
+	atomic_notifier_chain_register(&panic_notifier_list, &rcu_panic_block);
+	return 0;
+}
+early_initcall(check_cpu_stall_init);
+
+/* If so specified via sysctl, panic, yielding cleaner stall-warning output. */
+static void panic_on_rcu_stall(void)
+{
+	static int cpu_stall;
+
+	if (++cpu_stall < sysctl_max_rcu_stall_to_panic)
+		return;
+
+	if (sysctl_panic_on_rcu_stall)
+		panic("RCU Stall\n");
+}
+
+/**
+ * rcu_cpu_stall_reset - restart stall-warning timeout for current grace period
+ *
+ * To perform the reset request from the caller, disable stall detection until
+ * 3 fqs loops have passed. This is required to ensure a fresh jiffies is
+ * loaded.  It should be safe to do from the fqs loop as enough timer
+ * interrupts and context switches should have passed.
+ *
+ * The caller must disable hard irqs.
+ */
+void rcu_cpu_stall_reset(void)
+{
+	WRITE_ONCE(rcu_state.nr_fqs_jiffies_stall, 3);
+	WRITE_ONCE(rcu_state.jiffies_stall, ULONG_MAX);
+}
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// Interaction with RCU grace periods
+
+/* Start of new grace period, so record stall time (and forcing times). */
+static void record_gp_stall_check_time(void)
+{
+	unsigned long j = jiffies;
+	unsigned long j1;
+
+	WRITE_ONCE(rcu_state.gp_start, j);
+	j1 = rcu_jiffies_till_stall_check();
+	smp_mb(); // ->gp_start before ->jiffies_stall and caller's ->gp_seq.
+	WRITE_ONCE(rcu_state.nr_fqs_jiffies_stall, 0);
+	WRITE_ONCE(rcu_state.jiffies_stall, j + j1);
+	rcu_state.jiffies_resched = j + j1 / 2;
+	rcu_state.n_force_qs_gpstart = READ_ONCE(rcu_state.n_force_qs);
+}
+
+/* Zero ->ticks_this_gp and snapshot the number of RCU softirq handlers. */
+static void zero_cpu_stall_ticks(struct rcu_data *rdp)
+{
+	rdp->ticks_this_gp = 0;
+	rdp->softirq_snap = kstat_softirqs_cpu(RCU_SOFTIRQ, smp_processor_id());
+	WRITE_ONCE(rdp->last_fqs_resched, jiffies);
+}
+
+/*
+ * If too much time has passed in the current grace period, and if
+ * so configured, go kick the relevant kthreads.
+ */
+static void rcu_stall_kick_kthreads(void)
+{
+	unsigned long j;
+
+	if (!READ_ONCE(rcu_kick_kthreads))
+		return;
+	j = READ_ONCE(rcu_state.jiffies_kick_kthreads);
+	if (time_after(jiffies, j) && rcu_state.gp_kthread &&
+	    (rcu_gp_in_progress() || READ_ONCE(rcu_state.gp_flags))) {
+		WARN_ONCE(1, "Kicking %s grace-period kthread\n",
+			  rcu_state.name);
+		rcu_ftrace_dump(DUMP_ALL);
+		wake_up_process(rcu_state.gp_kthread);
+		WRITE_ONCE(rcu_state.jiffies_kick_kthreads, j + HZ);
+	}
+}
+
+/*
+ * Handler for the irq_work request posted about halfway into the RCU CPU
+ * stall timeout, and used to detect excessive irq disabling.  Set state
+ * appropriately, but just complain if there is unexpected state on entry.
+ */
+static void rcu_iw_handler(struct irq_work *iwp)
+{
+	struct rcu_data *rdp;
+	struct rcu_node *rnp;
+
+	rdp = container_of(iwp, struct rcu_data, rcu_iw);
+	rnp = rdp->mynode;
+	raw_spin_lock_rcu_node(rnp);
+	if (!WARN_ON_ONCE(!rdp->rcu_iw_pending)) {
+		rdp->rcu_iw_gp_seq = rnp->gp_seq;
+		rdp->rcu_iw_pending = false;
+	}
+	raw_spin_unlock_rcu_node(rnp);
+}
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// Printing RCU CPU stall warnings
+
+#ifdef CONFIG_PREEMPT_RCU
+
+/*
+ * Dump detailed information for all tasks blocking the current RCU
+ * grace period on the specified rcu_node structure.
+ */
+static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
+{
+	unsigned long flags;
+	struct task_struct *t;
+
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	if (!rcu_preempt_blocked_readers_cgp(rnp)) {
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		return;
+	}
+	t = list_entry(rnp->gp_tasks->prev,
+		       struct task_struct, rcu_node_entry);
+	list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) {
+		/*
+		 * We could be printing a lot while holding a spinlock.
+		 * Avoid triggering hard lockup.
+		 */
+		touch_nmi_watchdog();
+		sched_show_task(t);
+	}
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+}
+
+// Communicate task state back to the RCU CPU stall warning request.
+struct rcu_stall_chk_rdr {
+	int nesting;
+	union rcu_special rs;
+	bool on_blkd_list;
+};
+
+/*
+ * Report out the state of a not-running task that is stalling the
+ * current RCU grace period.
+ */
+static int check_slow_task(struct task_struct *t, void *arg)
+{
+	struct rcu_stall_chk_rdr *rscrp = arg;
+
+	if (task_curr(t))
+		return -EBUSY; // It is running, so decline to inspect it.
+	rscrp->nesting = t->rcu_read_lock_nesting;
+	rscrp->rs = t->rcu_read_unlock_special;
+	rscrp->on_blkd_list = !list_empty(&t->rcu_node_entry);
+	return 0;
+}
+
+/*
+ * Scan the current list of tasks blocked within RCU read-side critical
+ * sections, printing out the tid of each of the first few of them.
+ */
+static int rcu_print_task_stall(struct rcu_node *rnp, unsigned long flags)
+	__releases(rnp->lock)
+{
+	int i = 0;
+	int ndetected = 0;
+	struct rcu_stall_chk_rdr rscr;
+	struct task_struct *t;
+	struct task_struct *ts[8];
+
+	lockdep_assert_irqs_disabled();
+	if (!rcu_preempt_blocked_readers_cgp(rnp)) {
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		return 0;
+	}
+	pr_err("\tTasks blocked on level-%d rcu_node (CPUs %d-%d):",
+	       rnp->level, rnp->grplo, rnp->grphi);
+	t = list_entry(rnp->gp_tasks->prev,
+		       struct task_struct, rcu_node_entry);
+	list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) {
+		get_task_struct(t);
+		ts[i++] = t;
+		if (i >= ARRAY_SIZE(ts))
+			break;
+	}
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	while (i) {
+		t = ts[--i];
+		if (task_call_func(t, check_slow_task, &rscr))
+			pr_cont(" P%d", t->pid);
+		else
+			pr_cont(" P%d/%d:%c%c%c%c",
+				t->pid, rscr.nesting,
+				".b"[rscr.rs.b.blocked],
+				".q"[rscr.rs.b.need_qs],
+				".e"[rscr.rs.b.exp_hint],
+				".l"[rscr.on_blkd_list]);
+		lockdep_assert_irqs_disabled();
+		put_task_struct(t);
+		ndetected++;
+	}
+	pr_cont("\n");
+	return ndetected;
+}
+
+#else /* #ifdef CONFIG_PREEMPT_RCU */
+
+/*
+ * Because preemptible RCU does not exist, we never have to check for
+ * tasks blocked within RCU read-side critical sections.
+ */
+static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
+{
+}
+
+/*
+ * Because preemptible RCU does not exist, we never have to check for
+ * tasks blocked within RCU read-side critical sections.
+ */
+static int rcu_print_task_stall(struct rcu_node *rnp, unsigned long flags)
+	__releases(rnp->lock)
+{
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	return 0;
+}
+#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+
+/*
+ * Dump stacks of all tasks running on stalled CPUs.  First try using
+ * NMIs, but fall back to manual remote stack tracing on architectures
+ * that don't support NMI-based stack dumps.  The NMI-triggered stack
+ * traces are more accurate because they are printed by the target CPU.
+ */
+static void rcu_dump_cpu_stacks(void)
+{
+	int cpu;
+	unsigned long flags;
+	struct rcu_node *rnp;
+
+	rcu_for_each_leaf_node(rnp) {
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+		for_each_leaf_node_possible_cpu(rnp, cpu)
+			if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) {
+				if (cpu_is_offline(cpu))
+					pr_err("Offline CPU %d blocking current GP.\n", cpu);
+				else
+					dump_cpu_task(cpu);
+			}
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	}
+}
+
+static const char * const gp_state_names[] = {
+	[RCU_GP_IDLE] = "RCU_GP_IDLE",
+	[RCU_GP_WAIT_GPS] = "RCU_GP_WAIT_GPS",
+	[RCU_GP_DONE_GPS] = "RCU_GP_DONE_GPS",
+	[RCU_GP_ONOFF] = "RCU_GP_ONOFF",
+	[RCU_GP_INIT] = "RCU_GP_INIT",
+	[RCU_GP_WAIT_FQS] = "RCU_GP_WAIT_FQS",
+	[RCU_GP_DOING_FQS] = "RCU_GP_DOING_FQS",
+	[RCU_GP_CLEANUP] = "RCU_GP_CLEANUP",
+	[RCU_GP_CLEANED] = "RCU_GP_CLEANED",
+};
+
+/*
+ * Convert a ->gp_state value to a character string.
+ */
+static const char *gp_state_getname(short gs)
+{
+	if (gs < 0 || gs >= ARRAY_SIZE(gp_state_names))
+		return "???";
+	return gp_state_names[gs];
+}
+
+/* Is the RCU grace-period kthread being starved of CPU time? */
+static bool rcu_is_gp_kthread_starving(unsigned long *jp)
+{
+	unsigned long j = jiffies - READ_ONCE(rcu_state.gp_activity);
+
+	if (jp)
+		*jp = j;
+	return j > 2 * HZ;
+}
+
+static bool rcu_is_rcuc_kthread_starving(struct rcu_data *rdp, unsigned long *jp)
+{
+	int cpu;
+	struct task_struct *rcuc;
+	unsigned long j;
+
+	rcuc = rdp->rcu_cpu_kthread_task;
+	if (!rcuc)
+		return false;
+
+	cpu = task_cpu(rcuc);
+	if (cpu_is_offline(cpu) || idle_cpu(cpu))
+		return false;
+
+	j = jiffies - READ_ONCE(rdp->rcuc_activity);
+
+	if (jp)
+		*jp = j;
+	return j > 2 * HZ;
+}
+
+/*
+ * Print out diagnostic information for the specified stalled CPU.
+ *
+ * If the specified CPU is aware of the current RCU grace period, then
+ * print the number of scheduling clock interrupts the CPU has taken
+ * during the time that it has been aware.  Otherwise, print the number
+ * of RCU grace periods that this CPU is ignorant of, for example, "1"
+ * if the CPU was aware of the previous grace period.
+ *
+ * Also print out idle info.
+ */
+static void print_cpu_stall_info(int cpu)
+{
+	unsigned long delta;
+	bool falsepositive;
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+	char *ticks_title;
+	unsigned long ticks_value;
+	bool rcuc_starved;
+	unsigned long j;
+	char buf[32];
+
+	/*
+	 * We could be printing a lot while holding a spinlock.  Avoid
+	 * triggering hard lockup.
+	 */
+	touch_nmi_watchdog();
+
+	ticks_value = rcu_seq_ctr(rcu_state.gp_seq - rdp->gp_seq);
+	if (ticks_value) {
+		ticks_title = "GPs behind";
+	} else {
+		ticks_title = "ticks this GP";
+		ticks_value = rdp->ticks_this_gp;
+	}
+	delta = rcu_seq_ctr(rdp->mynode->gp_seq - rdp->rcu_iw_gp_seq);
+	falsepositive = rcu_is_gp_kthread_starving(NULL) &&
+			rcu_dynticks_in_eqs(rcu_dynticks_snap(cpu));
+	rcuc_starved = rcu_is_rcuc_kthread_starving(rdp, &j);
+	if (rcuc_starved)
+		sprintf(buf, " rcuc=%ld jiffies(starved)", j);
+	pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%04x/%ld/%#lx softirq=%u/%u fqs=%ld%s%s\n",
+	       cpu,
+	       "O."[!!cpu_online(cpu)],
+	       "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)],
+	       "N."[!!(rdp->grpmask & rdp->mynode->qsmaskinitnext)],
+	       !IS_ENABLED(CONFIG_IRQ_WORK) ? '?' :
+			rdp->rcu_iw_pending ? (int)min(delta, 9UL) + '0' :
+				"!."[!delta],
+	       ticks_value, ticks_title,
+	       rcu_dynticks_snap(cpu) & 0xffff,
+	       ct_dynticks_nesting_cpu(cpu), ct_dynticks_nmi_nesting_cpu(cpu),
+	       rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu),
+	       data_race(rcu_state.n_force_qs) - rcu_state.n_force_qs_gpstart,
+	       rcuc_starved ? buf : "",
+	       falsepositive ? " (false positive?)" : "");
+}
+
+/* Complain about starvation of grace-period kthread.  */
+static void rcu_check_gp_kthread_starvation(void)
+{
+	int cpu;
+	struct task_struct *gpk = rcu_state.gp_kthread;
+	unsigned long j;
+
+	if (rcu_is_gp_kthread_starving(&j)) {
+		cpu = gpk ? task_cpu(gpk) : -1;
+		pr_err("%s kthread starved for %ld jiffies! g%ld f%#x %s(%d) ->state=%#x ->cpu=%d\n",
+		       rcu_state.name, j,
+		       (long)rcu_seq_current(&rcu_state.gp_seq),
+		       data_race(READ_ONCE(rcu_state.gp_flags)),
+		       gp_state_getname(rcu_state.gp_state),
+		       data_race(READ_ONCE(rcu_state.gp_state)),
+		       gpk ? data_race(READ_ONCE(gpk->__state)) : ~0, cpu);
+		if (gpk) {
+			pr_err("\tUnless %s kthread gets sufficient CPU time, OOM is now expected behavior.\n", rcu_state.name);
+			pr_err("RCU grace-period kthread stack dump:\n");
+			sched_show_task(gpk);
+			if (cpu >= 0) {
+				if (cpu_is_offline(cpu)) {
+					pr_err("RCU GP kthread last ran on offline CPU %d.\n", cpu);
+				} else  {
+					pr_err("Stack dump where RCU GP kthread last ran:\n");
+					dump_cpu_task(cpu);
+				}
+			}
+			wake_up_process(gpk);
+		}
+	}
+}
+
+/* Complain about missing wakeups from expired fqs wait timer */
+static void rcu_check_gp_kthread_expired_fqs_timer(void)
+{
+	struct task_struct *gpk = rcu_state.gp_kthread;
+	short gp_state;
+	unsigned long jiffies_fqs;
+	int cpu;
+
+	/*
+	 * Order reads of .gp_state and .jiffies_force_qs.
+	 * Matching smp_wmb() is present in rcu_gp_fqs_loop().
+	 */
+	gp_state = smp_load_acquire(&rcu_state.gp_state);
+	jiffies_fqs = READ_ONCE(rcu_state.jiffies_force_qs);
+
+	if (gp_state == RCU_GP_WAIT_FQS &&
+	    time_after(jiffies, jiffies_fqs + RCU_STALL_MIGHT_MIN) &&
+	    gpk && !READ_ONCE(gpk->on_rq)) {
+		cpu = task_cpu(gpk);
+		pr_err("%s kthread timer wakeup didn't happen for %ld jiffies! g%ld f%#x %s(%d) ->state=%#x\n",
+		       rcu_state.name, (jiffies - jiffies_fqs),
+		       (long)rcu_seq_current(&rcu_state.gp_seq),
+		       data_race(rcu_state.gp_flags),
+		       gp_state_getname(RCU_GP_WAIT_FQS), RCU_GP_WAIT_FQS,
+		       data_race(READ_ONCE(gpk->__state)));
+		pr_err("\tPossible timer handling issue on cpu=%d timer-softirq=%u\n",
+		       cpu, kstat_softirqs_cpu(TIMER_SOFTIRQ, cpu));
+	}
+}
+
+static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps)
+{
+	int cpu;
+	unsigned long flags;
+	unsigned long gpa;
+	unsigned long j;
+	int ndetected = 0;
+	struct rcu_node *rnp;
+	long totqlen = 0;
+
+	lockdep_assert_irqs_disabled();
+
+	/* Kick and suppress, if so configured. */
+	rcu_stall_kick_kthreads();
+	if (rcu_stall_is_suppressed())
+		return;
+
+	/*
+	 * OK, time to rat on our buddy...
+	 * See Documentation/RCU/stallwarn.rst for info on how to debug
+	 * RCU CPU stall warnings.
+	 */
+	trace_rcu_stall_warning(rcu_state.name, TPS("StallDetected"));
+	pr_err("INFO: %s detected stalls on CPUs/tasks:\n", rcu_state.name);
+	rcu_for_each_leaf_node(rnp) {
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+		if (rnp->qsmask != 0) {
+			for_each_leaf_node_possible_cpu(rnp, cpu)
+				if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) {
+					print_cpu_stall_info(cpu);
+					ndetected++;
+				}
+		}
+		ndetected += rcu_print_task_stall(rnp, flags); // Releases rnp->lock.
+		lockdep_assert_irqs_disabled();
+	}
+
+	for_each_possible_cpu(cpu)
+		totqlen += rcu_get_n_cbs_cpu(cpu);
+	pr_cont("\t(detected by %d, t=%ld jiffies, g=%ld, q=%lu ncpus=%d)\n",
+	       smp_processor_id(), (long)(jiffies - gps),
+	       (long)rcu_seq_current(&rcu_state.gp_seq), totqlen, rcu_state.n_online_cpus);
+	if (ndetected) {
+		rcu_dump_cpu_stacks();
+
+		/* Complain about tasks blocking the grace period. */
+		rcu_for_each_leaf_node(rnp)
+			rcu_print_detail_task_stall_rnp(rnp);
+	} else {
+		if (rcu_seq_current(&rcu_state.gp_seq) != gp_seq) {
+			pr_err("INFO: Stall ended before state dump start\n");
+		} else {
+			j = jiffies;
+			gpa = data_race(READ_ONCE(rcu_state.gp_activity));
+			pr_err("All QSes seen, last %s kthread activity %ld (%ld-%ld), jiffies_till_next_fqs=%ld, root ->qsmask %#lx\n",
+			       rcu_state.name, j - gpa, j, gpa,
+			       data_race(READ_ONCE(jiffies_till_next_fqs)),
+			       data_race(READ_ONCE(rcu_get_root()->qsmask)));
+		}
+	}
+	/* Rewrite if needed in case of slow consoles. */
+	if (ULONG_CMP_GE(jiffies, READ_ONCE(rcu_state.jiffies_stall)))
+		WRITE_ONCE(rcu_state.jiffies_stall,
+			   jiffies + 3 * rcu_jiffies_till_stall_check() + 3);
+
+	rcu_check_gp_kthread_expired_fqs_timer();
+	rcu_check_gp_kthread_starvation();
+
+	panic_on_rcu_stall();
+
+	rcu_force_quiescent_state();  /* Kick them all. */
+}
+
+static void print_cpu_stall(unsigned long gps)
+{
+	int cpu;
+	unsigned long flags;
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
+	struct rcu_node *rnp = rcu_get_root();
+	long totqlen = 0;
+
+	lockdep_assert_irqs_disabled();
+
+	/* Kick and suppress, if so configured. */
+	rcu_stall_kick_kthreads();
+	if (rcu_stall_is_suppressed())
+		return;
+
+	/*
+	 * OK, time to rat on ourselves...
+	 * See Documentation/RCU/stallwarn.rst for info on how to debug
+	 * RCU CPU stall warnings.
+	 */
+	trace_rcu_stall_warning(rcu_state.name, TPS("SelfDetected"));
+	pr_err("INFO: %s self-detected stall on CPU\n", rcu_state.name);
+	raw_spin_lock_irqsave_rcu_node(rdp->mynode, flags);
+	print_cpu_stall_info(smp_processor_id());
+	raw_spin_unlock_irqrestore_rcu_node(rdp->mynode, flags);
+	for_each_possible_cpu(cpu)
+		totqlen += rcu_get_n_cbs_cpu(cpu);
+	pr_cont("\t(t=%lu jiffies g=%ld q=%lu ncpus=%d)\n",
+		jiffies - gps,
+		(long)rcu_seq_current(&rcu_state.gp_seq), totqlen, rcu_state.n_online_cpus);
+
+	rcu_check_gp_kthread_expired_fqs_timer();
+	rcu_check_gp_kthread_starvation();
+
+	rcu_dump_cpu_stacks();
+
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	/* Rewrite if needed in case of slow consoles. */
+	if (ULONG_CMP_GE(jiffies, READ_ONCE(rcu_state.jiffies_stall)))
+		WRITE_ONCE(rcu_state.jiffies_stall,
+			   jiffies + 3 * rcu_jiffies_till_stall_check() + 3);
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+
+	panic_on_rcu_stall();
+
+	/*
+	 * Attempt to revive the RCU machinery by forcing a context switch.
+	 *
+	 * A context switch would normally allow the RCU state machine to make
+	 * progress and it could be we're stuck in kernel space without context
+	 * switches for an entirely unreasonable amount of time.
+	 */
+	set_tsk_need_resched(current);
+	set_preempt_need_resched();
+}
+
+static void check_cpu_stall(struct rcu_data *rdp)
+{
+	bool didstall = false;
+	unsigned long gs1;
+	unsigned long gs2;
+	unsigned long gps;
+	unsigned long j;
+	unsigned long jn;
+	unsigned long js;
+	struct rcu_node *rnp;
+
+	lockdep_assert_irqs_disabled();
+	if ((rcu_stall_is_suppressed() && !READ_ONCE(rcu_kick_kthreads)) ||
+	    !rcu_gp_in_progress())
+		return;
+	rcu_stall_kick_kthreads();
+
+	/*
+	 * Check if it was requested (via rcu_cpu_stall_reset()) that the FQS
+	 * loop has to set jiffies to ensure a non-stale jiffies value. This
+	 * is required to have good jiffies value after coming out of long
+	 * breaks of jiffies updates. Not doing so can cause false positives.
+	 */
+	if (READ_ONCE(rcu_state.nr_fqs_jiffies_stall) > 0)
+		return;
+
+	j = jiffies;
+
+	/*
+	 * Lots of memory barriers to reject false positives.
+	 *
+	 * The idea is to pick up rcu_state.gp_seq, then
+	 * rcu_state.jiffies_stall, then rcu_state.gp_start, and finally
+	 * another copy of rcu_state.gp_seq.  These values are updated in
+	 * the opposite order with memory barriers (or equivalent) during
+	 * grace-period initialization and cleanup.  Now, a false positive
+	 * can occur if we get an new value of rcu_state.gp_start and a old
+	 * value of rcu_state.jiffies_stall.  But given the memory barriers,
+	 * the only way that this can happen is if one grace period ends
+	 * and another starts between these two fetches.  This is detected
+	 * by comparing the second fetch of rcu_state.gp_seq with the
+	 * previous fetch from rcu_state.gp_seq.
+	 *
+	 * Given this check, comparisons of jiffies, rcu_state.jiffies_stall,
+	 * and rcu_state.gp_start suffice to forestall false positives.
+	 */
+	gs1 = READ_ONCE(rcu_state.gp_seq);
+	smp_rmb(); /* Pick up ->gp_seq first... */
+	js = READ_ONCE(rcu_state.jiffies_stall);
+	smp_rmb(); /* ...then ->jiffies_stall before the rest... */
+	gps = READ_ONCE(rcu_state.gp_start);
+	smp_rmb(); /* ...and finally ->gp_start before ->gp_seq again. */
+	gs2 = READ_ONCE(rcu_state.gp_seq);
+	if (gs1 != gs2 ||
+	    ULONG_CMP_LT(j, js) ||
+	    ULONG_CMP_GE(gps, js))
+		return; /* No stall or GP completed since entering function. */
+	rnp = rdp->mynode;
+	jn = jiffies + ULONG_MAX / 2;
+	if (rcu_gp_in_progress() &&
+	    (READ_ONCE(rnp->qsmask) & rdp->grpmask) &&
+	    cmpxchg(&rcu_state.jiffies_stall, js, jn) == js) {
+
+		/*
+		 * If a virtual machine is stopped by the host it can look to
+		 * the watchdog like an RCU stall. Check to see if the host
+		 * stopped the vm.
+		 */
+		if (kvm_check_and_clear_guest_paused())
+			return;
+
+		/* We haven't checked in, so go dump stack. */
+		print_cpu_stall(gps);
+		if (READ_ONCE(rcu_cpu_stall_ftrace_dump))
+			rcu_ftrace_dump(DUMP_ALL);
+		didstall = true;
+
+	} else if (rcu_gp_in_progress() &&
+		   ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY) &&
+		   cmpxchg(&rcu_state.jiffies_stall, js, jn) == js) {
+
+		/*
+		 * If a virtual machine is stopped by the host it can look to
+		 * the watchdog like an RCU stall. Check to see if the host
+		 * stopped the vm.
+		 */
+		if (kvm_check_and_clear_guest_paused())
+			return;
+
+		/* They had a few time units to dump stack, so complain. */
+		print_other_cpu_stall(gs2, gps);
+		if (READ_ONCE(rcu_cpu_stall_ftrace_dump))
+			rcu_ftrace_dump(DUMP_ALL);
+		didstall = true;
+	}
+	if (didstall && READ_ONCE(rcu_state.jiffies_stall) == jn) {
+		jn = jiffies + 3 * rcu_jiffies_till_stall_check() + 3;
+		WRITE_ONCE(rcu_state.jiffies_stall, jn);
+	}
+}
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// RCU forward-progress mechanisms, including of callback invocation.
+
+
+/*
+ * Check to see if a failure to end RCU priority inversion was due to
+ * a CPU not passing through a quiescent state.  When this happens, there
+ * is nothing that RCU priority boosting can do to help, so we shouldn't
+ * count this as an RCU priority boosting failure.  A return of true says
+ * RCU priority boosting is to blame, and false says otherwise.  If false
+ * is returned, the first of the CPUs to blame is stored through cpup.
+ * If there was no CPU blocking the current grace period, but also nothing
+ * in need of being boosted, *cpup is set to -1.  This can happen in case
+ * of vCPU preemption while the last CPU is reporting its quiscent state,
+ * for example.
+ *
+ * If cpup is NULL, then a lockless quick check is carried out, suitable
+ * for high-rate usage.  On the other hand, if cpup is non-NULL, each
+ * rcu_node structure's ->lock is acquired, ruling out high-rate usage.
+ */
+bool rcu_check_boost_fail(unsigned long gp_state, int *cpup)
+{
+	bool atb = false;
+	int cpu;
+	unsigned long flags;
+	struct rcu_node *rnp;
+
+	rcu_for_each_leaf_node(rnp) {
+		if (!cpup) {
+			if (data_race(READ_ONCE(rnp->qsmask))) {
+				return false;
+			} else {
+				if (READ_ONCE(rnp->gp_tasks))
+					atb = true;
+				continue;
+			}
+		}
+		*cpup = -1;
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+		if (rnp->gp_tasks)
+			atb = true;
+		if (!rnp->qsmask) {
+			// No CPUs without quiescent states for this rnp.
+			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+			continue;
+		}
+		// Find the first holdout CPU.
+		for_each_leaf_node_possible_cpu(rnp, cpu) {
+			if (rnp->qsmask & (1UL << (cpu - rnp->grplo))) {
+				raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+				*cpup = cpu;
+				return false;
+			}
+		}
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	}
+	// Can't blame CPUs, so must blame RCU priority boosting.
+	return atb;
+}
+EXPORT_SYMBOL_GPL(rcu_check_boost_fail);
+
+/*
+ * Show the state of the grace-period kthreads.
+ */
+void show_rcu_gp_kthreads(void)
+{
+	unsigned long cbs = 0;
+	int cpu;
+	unsigned long j;
+	unsigned long ja;
+	unsigned long jr;
+	unsigned long js;
+	unsigned long jw;
+	struct rcu_data *rdp;
+	struct rcu_node *rnp;
+	struct task_struct *t = READ_ONCE(rcu_state.gp_kthread);
+
+	j = jiffies;
+	ja = j - data_race(READ_ONCE(rcu_state.gp_activity));
+	jr = j - data_race(READ_ONCE(rcu_state.gp_req_activity));
+	js = j - data_race(READ_ONCE(rcu_state.gp_start));
+	jw = j - data_race(READ_ONCE(rcu_state.gp_wake_time));
+	pr_info("%s: wait state: %s(%d) ->state: %#x ->rt_priority %u delta ->gp_start %lu ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_max %lu ->gp_flags %#x\n",
+		rcu_state.name, gp_state_getname(rcu_state.gp_state),
+		data_race(READ_ONCE(rcu_state.gp_state)),
+		t ? data_race(READ_ONCE(t->__state)) : 0x1ffff, t ? t->rt_priority : 0xffU,
+		js, ja, jr, jw, (long)data_race(READ_ONCE(rcu_state.gp_wake_seq)),
+		(long)data_race(READ_ONCE(rcu_state.gp_seq)),
+		(long)data_race(READ_ONCE(rcu_get_root()->gp_seq_needed)),
+		data_race(READ_ONCE(rcu_state.gp_max)),
+		data_race(READ_ONCE(rcu_state.gp_flags)));
+	rcu_for_each_node_breadth_first(rnp) {
+		if (ULONG_CMP_GE(READ_ONCE(rcu_state.gp_seq), READ_ONCE(rnp->gp_seq_needed)) &&
+		    !data_race(READ_ONCE(rnp->qsmask)) && !data_race(READ_ONCE(rnp->boost_tasks)) &&
+		    !data_race(READ_ONCE(rnp->exp_tasks)) && !data_race(READ_ONCE(rnp->gp_tasks)))
+			continue;
+		pr_info("\trcu_node %d:%d ->gp_seq %ld ->gp_seq_needed %ld ->qsmask %#lx %c%c%c%c ->n_boosts %ld\n",
+			rnp->grplo, rnp->grphi,
+			(long)data_race(READ_ONCE(rnp->gp_seq)),
+			(long)data_race(READ_ONCE(rnp->gp_seq_needed)),
+			data_race(READ_ONCE(rnp->qsmask)),
+			".b"[!!data_race(READ_ONCE(rnp->boost_kthread_task))],
+			".B"[!!data_race(READ_ONCE(rnp->boost_tasks))],
+			".E"[!!data_race(READ_ONCE(rnp->exp_tasks))],
+			".G"[!!data_race(READ_ONCE(rnp->gp_tasks))],
+			data_race(READ_ONCE(rnp->n_boosts)));
+		if (!rcu_is_leaf_node(rnp))
+			continue;
+		for_each_leaf_node_possible_cpu(rnp, cpu) {
+			rdp = per_cpu_ptr(&rcu_data, cpu);
+			if (READ_ONCE(rdp->gpwrap) ||
+			    ULONG_CMP_GE(READ_ONCE(rcu_state.gp_seq),
+					 READ_ONCE(rdp->gp_seq_needed)))
+				continue;
+			pr_info("\tcpu %d ->gp_seq_needed %ld\n",
+				cpu, (long)data_race(READ_ONCE(rdp->gp_seq_needed)));
+		}
+	}
+	for_each_possible_cpu(cpu) {
+		rdp = per_cpu_ptr(&rcu_data, cpu);
+		cbs += data_race(READ_ONCE(rdp->n_cbs_invoked));
+		if (rcu_segcblist_is_offloaded(&rdp->cblist))
+			show_rcu_nocb_state(rdp);
+	}
+	pr_info("RCU callbacks invoked since boot: %lu\n", cbs);
+	show_rcu_tasks_gp_kthreads();
+}
+EXPORT_SYMBOL_GPL(show_rcu_gp_kthreads);
+
+/*
+ * This function checks for grace-period requests that fail to motivate
+ * RCU to come out of its idle mode.
+ */
+static void rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp,
+				     const unsigned long gpssdelay)
+{
+	unsigned long flags;
+	unsigned long j;
+	struct rcu_node *rnp_root = rcu_get_root();
+	static atomic_t warned = ATOMIC_INIT(0);
+
+	if (!IS_ENABLED(CONFIG_PROVE_RCU) || rcu_gp_in_progress() ||
+	    ULONG_CMP_GE(READ_ONCE(rnp_root->gp_seq),
+			 READ_ONCE(rnp_root->gp_seq_needed)) ||
+	    !smp_load_acquire(&rcu_state.gp_kthread)) // Get stable kthread.
+		return;
+	j = jiffies; /* Expensive access, and in common case don't get here. */
+	if (time_before(j, READ_ONCE(rcu_state.gp_req_activity) + gpssdelay) ||
+	    time_before(j, READ_ONCE(rcu_state.gp_activity) + gpssdelay) ||
+	    atomic_read(&warned))
+		return;
+
+	raw_spin_lock_irqsave_rcu_node(rnp, flags);
+	j = jiffies;
+	if (rcu_gp_in_progress() ||
+	    ULONG_CMP_GE(READ_ONCE(rnp_root->gp_seq),
+			 READ_ONCE(rnp_root->gp_seq_needed)) ||
+	    time_before(j, READ_ONCE(rcu_state.gp_req_activity) + gpssdelay) ||
+	    time_before(j, READ_ONCE(rcu_state.gp_activity) + gpssdelay) ||
+	    atomic_read(&warned)) {
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		return;
+	}
+	/* Hold onto the leaf lock to make others see warned==1. */
+
+	if (rnp_root != rnp)
+		raw_spin_lock_rcu_node(rnp_root); /* irqs already disabled. */
+	j = jiffies;
+	if (rcu_gp_in_progress() ||
+	    ULONG_CMP_GE(READ_ONCE(rnp_root->gp_seq),
+			 READ_ONCE(rnp_root->gp_seq_needed)) ||
+	    time_before(j, READ_ONCE(rcu_state.gp_req_activity) + gpssdelay) ||
+	    time_before(j, READ_ONCE(rcu_state.gp_activity) + gpssdelay) ||
+	    atomic_xchg(&warned, 1)) {
+		if (rnp_root != rnp)
+			/* irqs remain disabled. */
+			raw_spin_unlock_rcu_node(rnp_root);
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+		return;
+	}
+	WARN_ON(1);
+	if (rnp_root != rnp)
+		raw_spin_unlock_rcu_node(rnp_root);
+	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	show_rcu_gp_kthreads();
+}
+
+/*
+ * Do a forward-progress check for rcutorture.  This is normally invoked
+ * due to an OOM event.  The argument "j" gives the time period during
+ * which rcutorture would like progress to have been made.
+ */
+void rcu_fwd_progress_check(unsigned long j)
+{
+	unsigned long cbs;
+	int cpu;
+	unsigned long max_cbs = 0;
+	int max_cpu = -1;
+	struct rcu_data *rdp;
+
+	if (rcu_gp_in_progress()) {
+		pr_info("%s: GP age %lu jiffies\n",
+			__func__, jiffies - data_race(READ_ONCE(rcu_state.gp_start)));
+		show_rcu_gp_kthreads();
+	} else {
+		pr_info("%s: Last GP end %lu jiffies ago\n",
+			__func__, jiffies - data_race(READ_ONCE(rcu_state.gp_end)));
+		preempt_disable();
+		rdp = this_cpu_ptr(&rcu_data);
+		rcu_check_gp_start_stall(rdp->mynode, rdp, j);
+		preempt_enable();
+	}
+	for_each_possible_cpu(cpu) {
+		cbs = rcu_get_n_cbs_cpu(cpu);
+		if (!cbs)
+			continue;
+		if (max_cpu < 0)
+			pr_info("%s: callbacks", __func__);
+		pr_cont(" %d: %lu", cpu, cbs);
+		if (cbs <= max_cbs)
+			continue;
+		max_cbs = cbs;
+		max_cpu = cpu;
+	}
+	if (max_cpu >= 0)
+		pr_cont("\n");
+}
+EXPORT_SYMBOL_GPL(rcu_fwd_progress_check);
+
+/* Commandeer a sysrq key to dump RCU's tree. */
+static bool sysrq_rcu;
+module_param(sysrq_rcu, bool, 0444);
+
+/* Dump grace-period-request information due to commandeered sysrq. */
+static void sysrq_show_rcu(int key)
+{
+	show_rcu_gp_kthreads();
+}
+
+static const struct sysrq_key_op sysrq_rcudump_op = {
+	.handler = sysrq_show_rcu,
+	.help_msg = "show-rcu(y)",
+	.action_msg = "Show RCU tree",
+	.enable_mask = SYSRQ_ENABLE_DUMP,
+};
+
+static int __init rcu_sysrq_init(void)
+{
+	if (sysrq_rcu)
+		return register_sysrq_key('y', &sysrq_rcudump_op);
+	return 0;
+}
+early_initcall(rcu_sysrq_init);
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
new file mode 100644
index 000000000..738842c48
--- /dev/null
+++ b/kernel/rcu/update.c
@@ -0,0 +1,628 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Read-Copy Update mechanism for mutual exclusion
+ *
+ * Copyright IBM Corporation, 2001
+ *
+ * Authors: Dipankar Sarma <dipankar@in.ibm.com>
+ *	    Manfred Spraul <manfred@colorfullife.com>
+ *
+ * Based on the original work by Paul McKenney <paulmck@linux.ibm.com>
+ * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
+ * Papers:
+ * http://www.rdrop.com/users/paulmck/paper/rclockpdcsproof.pdf
+ * http://lse.sourceforge.net/locking/rclock_OLS.2001.05.01c.sc.pdf (OLS2001)
+ *
+ * For detailed explanation of Read-Copy Update mechanism see -
+ *		http://lse.sourceforge.net/locking/rcupdate.html
+ *
+ */
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/debug.h>
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/cpu.h>
+#include <linux/mutex.h>
+#include <linux/export.h>
+#include <linux/hardirq.h>
+#include <linux/delay.h>
+#include <linux/moduleparam.h>
+#include <linux/kthread.h>
+#include <linux/tick.h>
+#include <linux/rcupdate_wait.h>
+#include <linux/sched/isolation.h>
+#include <linux/kprobes.h>
+#include <linux/slab.h>
+#include <linux/irq_work.h>
+#include <linux/rcupdate_trace.h>
+
+#define CREATE_TRACE_POINTS
+
+#include "rcu.h"
+
+#ifdef MODULE_PARAM_PREFIX
+#undef MODULE_PARAM_PREFIX
+#endif
+#define MODULE_PARAM_PREFIX "rcupdate."
+
+#ifndef CONFIG_TINY_RCU
+module_param(rcu_expedited, int, 0444);
+module_param(rcu_normal, int, 0444);
+static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT);
+#if !defined(CONFIG_PREEMPT_RT) || defined(CONFIG_NO_HZ_FULL)
+module_param(rcu_normal_after_boot, int, 0444);
+#endif
+#endif /* #ifndef CONFIG_TINY_RCU */
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+/**
+ * rcu_read_lock_held_common() - might we be in RCU-sched read-side critical section?
+ * @ret:	Best guess answer if lockdep cannot be relied on
+ *
+ * Returns true if lockdep must be ignored, in which case ``*ret`` contains
+ * the best guess described below.  Otherwise returns false, in which
+ * case ``*ret`` tells the caller nothing and the caller should instead
+ * consult lockdep.
+ *
+ * If CONFIG_DEBUG_LOCK_ALLOC is selected, set ``*ret`` to nonzero iff in an
+ * RCU-sched read-side critical section.  In absence of
+ * CONFIG_DEBUG_LOCK_ALLOC, this assumes we are in an RCU-sched read-side
+ * critical section unless it can prove otherwise.  Note that disabling
+ * of preemption (including disabling irqs) counts as an RCU-sched
+ * read-side critical section.  This is useful for debug checks in functions
+ * that required that they be called within an RCU-sched read-side
+ * critical section.
+ *
+ * Check debug_lockdep_rcu_enabled() to prevent false positives during boot
+ * and while lockdep is disabled.
+ *
+ * Note that if the CPU is in the idle loop from an RCU point of view (ie:
+ * that we are in the section between ct_idle_enter() and ct_idle_exit())
+ * then rcu_read_lock_held() sets ``*ret`` to false even if the CPU did an
+ * rcu_read_lock().  The reason for this is that RCU ignores CPUs that are
+ * in such a section, considering these as in extended quiescent state,
+ * so such a CPU is effectively never in an RCU read-side critical section
+ * regardless of what RCU primitives it invokes.  This state of affairs is
+ * required --- we need to keep an RCU-free window in idle where the CPU may
+ * possibly enter into low power mode. This way we can notice an extended
+ * quiescent state to other CPUs that started a grace period. Otherwise
+ * we would delay any grace period as long as we run in the idle task.
+ *
+ * Similarly, we avoid claiming an RCU read lock held if the current
+ * CPU is offline.
+ */
+static bool rcu_read_lock_held_common(bool *ret)
+{
+	if (!debug_lockdep_rcu_enabled()) {
+		*ret = true;
+		return true;
+	}
+	if (!rcu_is_watching()) {
+		*ret = false;
+		return true;
+	}
+	if (!rcu_lockdep_current_cpu_online()) {
+		*ret = false;
+		return true;
+	}
+	return false;
+}
+
+int rcu_read_lock_sched_held(void)
+{
+	bool ret;
+
+	if (rcu_read_lock_held_common(&ret))
+		return ret;
+	return lock_is_held(&rcu_sched_lock_map) || !preemptible();
+}
+EXPORT_SYMBOL(rcu_read_lock_sched_held);
+#endif
+
+#ifndef CONFIG_TINY_RCU
+
+/*
+ * Should expedited grace-period primitives always fall back to their
+ * non-expedited counterparts?  Intended for use within RCU.  Note
+ * that if the user specifies both rcu_expedited and rcu_normal, then
+ * rcu_normal wins.  (Except during the time period during boot from
+ * when the first task is spawned until the rcu_set_runtime_mode()
+ * core_initcall() is invoked, at which point everything is expedited.)
+ */
+bool rcu_gp_is_normal(void)
+{
+	return READ_ONCE(rcu_normal) &&
+	       rcu_scheduler_active != RCU_SCHEDULER_INIT;
+}
+EXPORT_SYMBOL_GPL(rcu_gp_is_normal);
+
+static atomic_t rcu_expedited_nesting = ATOMIC_INIT(1);
+
+/*
+ * Should normal grace-period primitives be expedited?  Intended for
+ * use within RCU.  Note that this function takes the rcu_expedited
+ * sysfs/boot variable and rcu_scheduler_active into account as well
+ * as the rcu_expedite_gp() nesting.  So looping on rcu_unexpedite_gp()
+ * until rcu_gp_is_expedited() returns false is a -really- bad idea.
+ */
+bool rcu_gp_is_expedited(void)
+{
+	return rcu_expedited || atomic_read(&rcu_expedited_nesting);
+}
+EXPORT_SYMBOL_GPL(rcu_gp_is_expedited);
+
+/**
+ * rcu_expedite_gp - Expedite future RCU grace periods
+ *
+ * After a call to this function, future calls to synchronize_rcu() and
+ * friends act as the corresponding synchronize_rcu_expedited() function
+ * had instead been called.
+ */
+void rcu_expedite_gp(void)
+{
+	atomic_inc(&rcu_expedited_nesting);
+}
+EXPORT_SYMBOL_GPL(rcu_expedite_gp);
+
+/**
+ * rcu_unexpedite_gp - Cancel prior rcu_expedite_gp() invocation
+ *
+ * Undo a prior call to rcu_expedite_gp().  If all prior calls to
+ * rcu_expedite_gp() are undone by a subsequent call to rcu_unexpedite_gp(),
+ * and if the rcu_expedited sysfs/boot parameter is not set, then all
+ * subsequent calls to synchronize_rcu() and friends will return to
+ * their normal non-expedited behavior.
+ */
+void rcu_unexpedite_gp(void)
+{
+	atomic_dec(&rcu_expedited_nesting);
+}
+EXPORT_SYMBOL_GPL(rcu_unexpedite_gp);
+
+static bool rcu_boot_ended __read_mostly;
+
+/*
+ * Inform RCU of the end of the in-kernel boot sequence.
+ */
+void rcu_end_inkernel_boot(void)
+{
+	rcu_unexpedite_gp();
+	if (rcu_normal_after_boot)
+		WRITE_ONCE(rcu_normal, 1);
+	rcu_boot_ended = true;
+}
+
+/*
+ * Let rcutorture know when it is OK to turn it up to eleven.
+ */
+bool rcu_inkernel_boot_has_ended(void)
+{
+	return rcu_boot_ended;
+}
+EXPORT_SYMBOL_GPL(rcu_inkernel_boot_has_ended);
+
+#endif /* #ifndef CONFIG_TINY_RCU */
+
+/*
+ * Test each non-SRCU synchronous grace-period wait API.  This is
+ * useful just after a change in mode for these primitives, and
+ * during early boot.
+ */
+void rcu_test_sync_prims(void)
+{
+	if (!IS_ENABLED(CONFIG_PROVE_RCU))
+		return;
+	synchronize_rcu();
+	synchronize_rcu_expedited();
+}
+
+#if !defined(CONFIG_TINY_RCU) || defined(CONFIG_SRCU)
+
+/*
+ * Switch to run-time mode once RCU has fully initialized.
+ */
+static int __init rcu_set_runtime_mode(void)
+{
+	rcu_test_sync_prims();
+	rcu_scheduler_active = RCU_SCHEDULER_RUNNING;
+	kfree_rcu_scheduler_running();
+	rcu_test_sync_prims();
+	return 0;
+}
+core_initcall(rcu_set_runtime_mode);
+
+#endif /* #if !defined(CONFIG_TINY_RCU) || defined(CONFIG_SRCU) */
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+static struct lock_class_key rcu_lock_key;
+struct lockdep_map rcu_lock_map = {
+	.name = "rcu_read_lock",
+	.key = &rcu_lock_key,
+	.wait_type_outer = LD_WAIT_FREE,
+	.wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_RT implies PREEMPT_RCU */
+};
+EXPORT_SYMBOL_GPL(rcu_lock_map);
+
+static struct lock_class_key rcu_bh_lock_key;
+struct lockdep_map rcu_bh_lock_map = {
+	.name = "rcu_read_lock_bh",
+	.key = &rcu_bh_lock_key,
+	.wait_type_outer = LD_WAIT_FREE,
+	.wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_RT makes BH preemptible. */
+};
+EXPORT_SYMBOL_GPL(rcu_bh_lock_map);
+
+static struct lock_class_key rcu_sched_lock_key;
+struct lockdep_map rcu_sched_lock_map = {
+	.name = "rcu_read_lock_sched",
+	.key = &rcu_sched_lock_key,
+	.wait_type_outer = LD_WAIT_FREE,
+	.wait_type_inner = LD_WAIT_SPIN,
+};
+EXPORT_SYMBOL_GPL(rcu_sched_lock_map);
+
+// Tell lockdep when RCU callbacks are being invoked.
+static struct lock_class_key rcu_callback_key;
+struct lockdep_map rcu_callback_map =
+	STATIC_LOCKDEP_MAP_INIT("rcu_callback", &rcu_callback_key);
+EXPORT_SYMBOL_GPL(rcu_callback_map);
+
+noinstr int notrace debug_lockdep_rcu_enabled(void)
+{
+	return rcu_scheduler_active != RCU_SCHEDULER_INACTIVE && READ_ONCE(debug_locks) &&
+	       current->lockdep_recursion == 0;
+}
+EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled);
+
+/**
+ * rcu_read_lock_held() - might we be in RCU read-side critical section?
+ *
+ * If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an RCU
+ * read-side critical section.  In absence of CONFIG_DEBUG_LOCK_ALLOC,
+ * this assumes we are in an RCU read-side critical section unless it can
+ * prove otherwise.  This is useful for debug checks in functions that
+ * require that they be called within an RCU read-side critical section.
+ *
+ * Checks debug_lockdep_rcu_enabled() to prevent false positives during boot
+ * and while lockdep is disabled.
+ *
+ * Note that rcu_read_lock() and the matching rcu_read_unlock() must
+ * occur in the same context, for example, it is illegal to invoke
+ * rcu_read_unlock() in process context if the matching rcu_read_lock()
+ * was invoked from within an irq handler.
+ *
+ * Note that rcu_read_lock() is disallowed if the CPU is either idle or
+ * offline from an RCU perspective, so check for those as well.
+ */
+int rcu_read_lock_held(void)
+{
+	bool ret;
+
+	if (rcu_read_lock_held_common(&ret))
+		return ret;
+	return lock_is_held(&rcu_lock_map);
+}
+EXPORT_SYMBOL_GPL(rcu_read_lock_held);
+
+/**
+ * rcu_read_lock_bh_held() - might we be in RCU-bh read-side critical section?
+ *
+ * Check for bottom half being disabled, which covers both the
+ * CONFIG_PROVE_RCU and not cases.  Note that if someone uses
+ * rcu_read_lock_bh(), but then later enables BH, lockdep (if enabled)
+ * will show the situation.  This is useful for debug checks in functions
+ * that require that they be called within an RCU read-side critical
+ * section.
+ *
+ * Check debug_lockdep_rcu_enabled() to prevent false positives during boot.
+ *
+ * Note that rcu_read_lock_bh() is disallowed if the CPU is either idle or
+ * offline from an RCU perspective, so check for those as well.
+ */
+int rcu_read_lock_bh_held(void)
+{
+	bool ret;
+
+	if (rcu_read_lock_held_common(&ret))
+		return ret;
+	return in_softirq() || irqs_disabled();
+}
+EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held);
+
+int rcu_read_lock_any_held(void)
+{
+	bool ret;
+
+	if (rcu_read_lock_held_common(&ret))
+		return ret;
+	if (lock_is_held(&rcu_lock_map) ||
+	    lock_is_held(&rcu_bh_lock_map) ||
+	    lock_is_held(&rcu_sched_lock_map))
+		return 1;
+	return !preemptible();
+}
+EXPORT_SYMBOL_GPL(rcu_read_lock_any_held);
+
+#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+
+/**
+ * wakeme_after_rcu() - Callback function to awaken a task after grace period
+ * @head: Pointer to rcu_head member within rcu_synchronize structure
+ *
+ * Awaken the corresponding task now that a grace period has elapsed.
+ */
+void wakeme_after_rcu(struct rcu_head *head)
+{
+	struct rcu_synchronize *rcu;
+
+	rcu = container_of(head, struct rcu_synchronize, head);
+	complete(&rcu->completion);
+}
+EXPORT_SYMBOL_GPL(wakeme_after_rcu);
+
+void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
+		   struct rcu_synchronize *rs_array)
+{
+	int i;
+	int j;
+
+	/* Initialize and register callbacks for each crcu_array element. */
+	for (i = 0; i < n; i++) {
+		if (checktiny &&
+		    (crcu_array[i] == call_rcu)) {
+			might_sleep();
+			continue;
+		}
+		for (j = 0; j < i; j++)
+			if (crcu_array[j] == crcu_array[i])
+				break;
+		if (j == i) {
+			init_rcu_head_on_stack(&rs_array[i].head);
+			init_completion(&rs_array[i].completion);
+			(crcu_array[i])(&rs_array[i].head, wakeme_after_rcu);
+		}
+	}
+
+	/* Wait for all callbacks to be invoked. */
+	for (i = 0; i < n; i++) {
+		if (checktiny &&
+		    (crcu_array[i] == call_rcu))
+			continue;
+		for (j = 0; j < i; j++)
+			if (crcu_array[j] == crcu_array[i])
+				break;
+		if (j == i) {
+			wait_for_completion(&rs_array[i].completion);
+			destroy_rcu_head_on_stack(&rs_array[i].head);
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(__wait_rcu_gp);
+
+void finish_rcuwait(struct rcuwait *w)
+{
+	rcu_assign_pointer(w->task, NULL);
+	__set_current_state(TASK_RUNNING);
+}
+EXPORT_SYMBOL_GPL(finish_rcuwait);
+
+#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
+void init_rcu_head(struct rcu_head *head)
+{
+	debug_object_init(head, &rcuhead_debug_descr);
+}
+EXPORT_SYMBOL_GPL(init_rcu_head);
+
+void destroy_rcu_head(struct rcu_head *head)
+{
+	debug_object_free(head, &rcuhead_debug_descr);
+}
+EXPORT_SYMBOL_GPL(destroy_rcu_head);
+
+static bool rcuhead_is_static_object(void *addr)
+{
+	return true;
+}
+
+/**
+ * init_rcu_head_on_stack() - initialize on-stack rcu_head for debugobjects
+ * @head: pointer to rcu_head structure to be initialized
+ *
+ * This function informs debugobjects of a new rcu_head structure that
+ * has been allocated as an auto variable on the stack.  This function
+ * is not required for rcu_head structures that are statically defined or
+ * that are dynamically allocated on the heap.  This function has no
+ * effect for !CONFIG_DEBUG_OBJECTS_RCU_HEAD kernel builds.
+ */
+void init_rcu_head_on_stack(struct rcu_head *head)
+{
+	debug_object_init_on_stack(head, &rcuhead_debug_descr);
+}
+EXPORT_SYMBOL_GPL(init_rcu_head_on_stack);
+
+/**
+ * destroy_rcu_head_on_stack() - destroy on-stack rcu_head for debugobjects
+ * @head: pointer to rcu_head structure to be initialized
+ *
+ * This function informs debugobjects that an on-stack rcu_head structure
+ * is about to go out of scope.  As with init_rcu_head_on_stack(), this
+ * function is not required for rcu_head structures that are statically
+ * defined or that are dynamically allocated on the heap.  Also as with
+ * init_rcu_head_on_stack(), this function has no effect for
+ * !CONFIG_DEBUG_OBJECTS_RCU_HEAD kernel builds.
+ */
+void destroy_rcu_head_on_stack(struct rcu_head *head)
+{
+	debug_object_free(head, &rcuhead_debug_descr);
+}
+EXPORT_SYMBOL_GPL(destroy_rcu_head_on_stack);
+
+const struct debug_obj_descr rcuhead_debug_descr = {
+	.name = "rcu_head",
+	.is_static_object = rcuhead_is_static_object,
+};
+EXPORT_SYMBOL_GPL(rcuhead_debug_descr);
+#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+
+#if defined(CONFIG_TREE_RCU) || defined(CONFIG_RCU_TRACE)
+void do_trace_rcu_torture_read(const char *rcutorturename, struct rcu_head *rhp,
+			       unsigned long secs,
+			       unsigned long c_old, unsigned long c)
+{
+	trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c);
+}
+EXPORT_SYMBOL_GPL(do_trace_rcu_torture_read);
+#else
+#define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
+	do { } while (0)
+#endif
+
+#if IS_ENABLED(CONFIG_RCU_TORTURE_TEST) || IS_MODULE(CONFIG_RCU_TORTURE_TEST)
+/* Get rcutorture access to sched_setaffinity(). */
+long rcutorture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+{
+	int ret;
+
+	ret = sched_setaffinity(pid, in_mask);
+	WARN_ONCE(ret, "%s: sched_setaffinity() returned %d\n", __func__, ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rcutorture_sched_setaffinity);
+#endif
+
+#ifdef CONFIG_RCU_STALL_COMMON
+int rcu_cpu_stall_ftrace_dump __read_mostly;
+module_param(rcu_cpu_stall_ftrace_dump, int, 0644);
+int rcu_cpu_stall_suppress __read_mostly; // !0 = suppress stall warnings.
+EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress);
+module_param(rcu_cpu_stall_suppress, int, 0644);
+int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
+module_param(rcu_cpu_stall_timeout, int, 0644);
+int rcu_exp_cpu_stall_timeout __read_mostly = CONFIG_RCU_EXP_CPU_STALL_TIMEOUT;
+module_param(rcu_exp_cpu_stall_timeout, int, 0644);
+#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
+
+// Suppress boot-time RCU CPU stall warnings and rcutorture writer stall
+// warnings.  Also used by rcutorture even if stall warnings are excluded.
+int rcu_cpu_stall_suppress_at_boot __read_mostly; // !0 = suppress boot stalls.
+EXPORT_SYMBOL_GPL(rcu_cpu_stall_suppress_at_boot);
+module_param(rcu_cpu_stall_suppress_at_boot, int, 0444);
+
+/**
+ * get_completed_synchronize_rcu - Return a pre-completed polled state cookie
+ *
+ * Returns a value that will always be treated by functions like
+ * poll_state_synchronize_rcu() as a cookie whose grace period has already
+ * completed.
+ */
+unsigned long get_completed_synchronize_rcu(void)
+{
+	return RCU_GET_STATE_COMPLETED;
+}
+EXPORT_SYMBOL_GPL(get_completed_synchronize_rcu);
+
+#ifdef CONFIG_PROVE_RCU
+
+/*
+ * Early boot self test parameters.
+ */
+static bool rcu_self_test;
+module_param(rcu_self_test, bool, 0444);
+
+static int rcu_self_test_counter;
+
+static void test_callback(struct rcu_head *r)
+{
+	rcu_self_test_counter++;
+	pr_info("RCU test callback executed %d\n", rcu_self_test_counter);
+}
+
+DEFINE_STATIC_SRCU(early_srcu);
+static unsigned long early_srcu_cookie;
+
+struct early_boot_kfree_rcu {
+	struct rcu_head rh;
+};
+
+static void early_boot_test_call_rcu(void)
+{
+	static struct rcu_head head;
+	static struct rcu_head shead;
+	struct early_boot_kfree_rcu *rhp;
+
+	call_rcu(&head, test_callback);
+	if (IS_ENABLED(CONFIG_SRCU)) {
+		early_srcu_cookie = start_poll_synchronize_srcu(&early_srcu);
+		call_srcu(&early_srcu, &shead, test_callback);
+	}
+	rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
+	if (!WARN_ON_ONCE(!rhp))
+		kfree_rcu(rhp, rh);
+}
+
+void rcu_early_boot_tests(void)
+{
+	pr_info("Running RCU self tests\n");
+
+	if (rcu_self_test)
+		early_boot_test_call_rcu();
+	rcu_test_sync_prims();
+}
+
+static int rcu_verify_early_boot_tests(void)
+{
+	int ret = 0;
+	int early_boot_test_counter = 0;
+
+	if (rcu_self_test) {
+		early_boot_test_counter++;
+		rcu_barrier();
+		if (IS_ENABLED(CONFIG_SRCU)) {
+			early_boot_test_counter++;
+			srcu_barrier(&early_srcu);
+			WARN_ON_ONCE(!poll_state_synchronize_srcu(&early_srcu, early_srcu_cookie));
+		}
+	}
+	if (rcu_self_test_counter != early_boot_test_counter) {
+		WARN_ON(1);
+		ret = -1;
+	}
+
+	return ret;
+}
+late_initcall(rcu_verify_early_boot_tests);
+#else
+void rcu_early_boot_tests(void) {}
+#endif /* CONFIG_PROVE_RCU */
+
+#include "tasks.h"
+
+#ifndef CONFIG_TINY_RCU
+
+/*
+ * Print any significant non-default boot-time settings.
+ */
+void __init rcupdate_announce_bootup_oddness(void)
+{
+	if (rcu_normal)
+		pr_info("\tNo expedited grace period (rcu_normal).\n");
+	else if (rcu_normal_after_boot)
+		pr_info("\tNo expedited grace period (rcu_normal_after_boot).\n");
+	else if (rcu_expedited)
+		pr_info("\tAll grace periods are expedited (rcu_expedited).\n");
+	if (rcu_cpu_stall_suppress)
+		pr_info("\tRCU CPU stall warnings suppressed (rcu_cpu_stall_suppress).\n");
+	if (rcu_cpu_stall_timeout != CONFIG_RCU_CPU_STALL_TIMEOUT)
+		pr_info("\tRCU CPU stall warnings timeout set to %d (rcu_cpu_stall_timeout).\n", rcu_cpu_stall_timeout);
+	rcu_tasks_bootup_oddness();
+}
+
+#endif /* #ifndef CONFIG_TINY_RCU */
diff --git a/kernel/reboot.c b/kernel/reboot.c
new file mode 100644
index 000000000..6ebef11c8
--- /dev/null
+++ b/kernel/reboot.c
@@ -0,0 +1,1312 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/kernel/reboot.c
+ *
+ *  Copyright (C) 2013  Linus Torvalds
+ */
+
+#define pr_fmt(fmt)	"reboot: " fmt
+
+#include <linux/atomic.h>
+#include <linux/ctype.h>
+#include <linux/export.h>
+#include <linux/kexec.h>
+#include <linux/kmod.h>
+#include <linux/kmsg_dump.h>
+#include <linux/reboot.h>
+#include <linux/suspend.h>
+#include <linux/syscalls.h>
+#include <linux/syscore_ops.h>
+#include <linux/uaccess.h>
+
+/*
+ * this indicates whether you can reboot with ctrl-alt-del: the default is yes
+ */
+
+static int C_A_D = 1;
+struct pid *cad_pid;
+EXPORT_SYMBOL(cad_pid);
+
+#if defined(CONFIG_ARM)
+#define DEFAULT_REBOOT_MODE		= REBOOT_HARD
+#else
+#define DEFAULT_REBOOT_MODE
+#endif
+enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
+EXPORT_SYMBOL_GPL(reboot_mode);
+enum reboot_mode panic_reboot_mode = REBOOT_UNDEFINED;
+
+/*
+ * This variable is used privately to keep track of whether or not
+ * reboot_type is still set to its default value (i.e., reboot= hasn't
+ * been set on the command line).  This is needed so that we can
+ * suppress DMI scanning for reboot quirks.  Without it, it's
+ * impossible to override a faulty reboot quirk without recompiling.
+ */
+int reboot_default = 1;
+int reboot_cpu;
+enum reboot_type reboot_type = BOOT_ACPI;
+int reboot_force;
+
+struct sys_off_handler {
+	struct notifier_block nb;
+	int (*sys_off_cb)(struct sys_off_data *data);
+	void *cb_data;
+	enum sys_off_mode mode;
+	bool blocking;
+	void *list;
+};
+
+/*
+ * Temporary stub that prevents linkage failure while we're in process
+ * of removing all uses of legacy pm_power_off() around the kernel.
+ */
+void __weak (*pm_power_off)(void);
+
+/**
+ *	emergency_restart - reboot the system
+ *
+ *	Without shutting down any hardware or taking any locks
+ *	reboot the system.  This is called when we know we are in
+ *	trouble so this is our best effort to reboot.  This is
+ *	safe to call in interrupt context.
+ */
+void emergency_restart(void)
+{
+	kmsg_dump(KMSG_DUMP_EMERG);
+	system_state = SYSTEM_RESTART;
+	machine_emergency_restart();
+}
+EXPORT_SYMBOL_GPL(emergency_restart);
+
+void kernel_restart_prepare(char *cmd)
+{
+	blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
+	system_state = SYSTEM_RESTART;
+	usermodehelper_disable();
+	device_shutdown();
+}
+
+/**
+ *	register_reboot_notifier - Register function to be called at reboot time
+ *	@nb: Info about notifier function to be called
+ *
+ *	Registers a function with the list of functions
+ *	to be called at reboot time.
+ *
+ *	Currently always returns zero, as blocking_notifier_chain_register()
+ *	always returns zero.
+ */
+int register_reboot_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&reboot_notifier_list, nb);
+}
+EXPORT_SYMBOL(register_reboot_notifier);
+
+/**
+ *	unregister_reboot_notifier - Unregister previously registered reboot notifier
+ *	@nb: Hook to be unregistered
+ *
+ *	Unregisters a previously registered reboot
+ *	notifier function.
+ *
+ *	Returns zero on success, or %-ENOENT on failure.
+ */
+int unregister_reboot_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
+}
+EXPORT_SYMBOL(unregister_reboot_notifier);
+
+static void devm_unregister_reboot_notifier(struct device *dev, void *res)
+{
+	WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res));
+}
+
+int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb)
+{
+	struct notifier_block **rcnb;
+	int ret;
+
+	rcnb = devres_alloc(devm_unregister_reboot_notifier,
+			    sizeof(*rcnb), GFP_KERNEL);
+	if (!rcnb)
+		return -ENOMEM;
+
+	ret = register_reboot_notifier(nb);
+	if (!ret) {
+		*rcnb = nb;
+		devres_add(dev, rcnb);
+	} else {
+		devres_free(rcnb);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(devm_register_reboot_notifier);
+
+/*
+ *	Notifier list for kernel code which wants to be called
+ *	to restart the system.
+ */
+static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
+
+/**
+ *	register_restart_handler - Register function to be called to reset
+ *				   the system
+ *	@nb: Info about handler function to be called
+ *	@nb->priority:	Handler priority. Handlers should follow the
+ *			following guidelines for setting priorities.
+ *			0:	Restart handler of last resort,
+ *				with limited restart capabilities
+ *			128:	Default restart handler; use if no other
+ *				restart handler is expected to be available,
+ *				and/or if restart functionality is
+ *				sufficient to restart the entire system
+ *			255:	Highest priority restart handler, will
+ *				preempt all other restart handlers
+ *
+ *	Registers a function with code to be called to restart the
+ *	system.
+ *
+ *	Registered functions will be called from machine_restart as last
+ *	step of the restart sequence (if the architecture specific
+ *	machine_restart function calls do_kernel_restart - see below
+ *	for details).
+ *	Registered functions are expected to restart the system immediately.
+ *	If more than one function is registered, the restart handler priority
+ *	selects which function will be called first.
+ *
+ *	Restart handlers are expected to be registered from non-architecture
+ *	code, typically from drivers. A typical use case would be a system
+ *	where restart functionality is provided through a watchdog. Multiple
+ *	restart handlers may exist; for example, one restart handler might
+ *	restart the entire system, while another only restarts the CPU.
+ *	In such cases, the restart handler which only restarts part of the
+ *	hardware is expected to register with low priority to ensure that
+ *	it only runs if no other means to restart the system is available.
+ *
+ *	Currently always returns zero, as atomic_notifier_chain_register()
+ *	always returns zero.
+ */
+int register_restart_handler(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_register(&restart_handler_list, nb);
+}
+EXPORT_SYMBOL(register_restart_handler);
+
+/**
+ *	unregister_restart_handler - Unregister previously registered
+ *				     restart handler
+ *	@nb: Hook to be unregistered
+ *
+ *	Unregisters a previously registered restart handler function.
+ *
+ *	Returns zero on success, or %-ENOENT on failure.
+ */
+int unregister_restart_handler(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_unregister(&restart_handler_list, nb);
+}
+EXPORT_SYMBOL(unregister_restart_handler);
+
+/**
+ *	do_kernel_restart - Execute kernel restart handler call chain
+ *
+ *	Calls functions registered with register_restart_handler.
+ *
+ *	Expected to be called from machine_restart as last step of the restart
+ *	sequence.
+ *
+ *	Restarts the system immediately if a restart handler function has been
+ *	registered. Otherwise does nothing.
+ */
+void do_kernel_restart(char *cmd)
+{
+	atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd);
+}
+
+void migrate_to_reboot_cpu(void)
+{
+	/* The boot cpu is always logical cpu 0 */
+	int cpu = reboot_cpu;
+
+	cpu_hotplug_disable();
+
+	/* Make certain the cpu I'm about to reboot on is online */
+	if (!cpu_online(cpu))
+		cpu = cpumask_first(cpu_online_mask);
+
+	/* Prevent races with other tasks migrating this task */
+	current->flags |= PF_NO_SETAFFINITY;
+
+	/* Make certain I only run on the appropriate processor */
+	set_cpus_allowed_ptr(current, cpumask_of(cpu));
+}
+
+/*
+ *	Notifier list for kernel code which wants to be called
+ *	to prepare system for restart.
+ */
+static BLOCKING_NOTIFIER_HEAD(restart_prep_handler_list);
+
+static void do_kernel_restart_prepare(void)
+{
+	blocking_notifier_call_chain(&restart_prep_handler_list, 0, NULL);
+}
+
+/**
+ *	kernel_restart - reboot the system
+ *	@cmd: pointer to buffer containing command to execute for restart
+ *		or %NULL
+ *
+ *	Shutdown everything and perform a clean reboot.
+ *	This is not safe to call in interrupt context.
+ */
+void kernel_restart(char *cmd)
+{
+	kernel_restart_prepare(cmd);
+	do_kernel_restart_prepare();
+	migrate_to_reboot_cpu();
+	syscore_shutdown();
+	if (!cmd)
+		pr_emerg("Restarting system\n");
+	else
+		pr_emerg("Restarting system with command '%s'\n", cmd);
+	kmsg_dump(KMSG_DUMP_SHUTDOWN);
+	machine_restart(cmd);
+}
+EXPORT_SYMBOL_GPL(kernel_restart);
+
+static void kernel_shutdown_prepare(enum system_states state)
+{
+	blocking_notifier_call_chain(&reboot_notifier_list,
+		(state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL);
+	system_state = state;
+	usermodehelper_disable();
+	device_shutdown();
+}
+/**
+ *	kernel_halt - halt the system
+ *
+ *	Shutdown everything and perform a clean system halt.
+ */
+void kernel_halt(void)
+{
+	kernel_shutdown_prepare(SYSTEM_HALT);
+	migrate_to_reboot_cpu();
+	syscore_shutdown();
+	pr_emerg("System halted\n");
+	kmsg_dump(KMSG_DUMP_SHUTDOWN);
+	machine_halt();
+}
+EXPORT_SYMBOL_GPL(kernel_halt);
+
+/*
+ *	Notifier list for kernel code which wants to be called
+ *	to prepare system for power off.
+ */
+static BLOCKING_NOTIFIER_HEAD(power_off_prep_handler_list);
+
+/*
+ *	Notifier list for kernel code which wants to be called
+ *	to power off system.
+ */
+static ATOMIC_NOTIFIER_HEAD(power_off_handler_list);
+
+static int sys_off_notify(struct notifier_block *nb,
+			  unsigned long mode, void *cmd)
+{
+	struct sys_off_handler *handler;
+	struct sys_off_data data = {};
+
+	handler = container_of(nb, struct sys_off_handler, nb);
+	data.cb_data = handler->cb_data;
+	data.mode = mode;
+	data.cmd = cmd;
+
+	return handler->sys_off_cb(&data);
+}
+
+static struct sys_off_handler platform_sys_off_handler;
+
+static struct sys_off_handler *alloc_sys_off_handler(int priority)
+{
+	struct sys_off_handler *handler;
+	gfp_t flags;
+
+	/*
+	 * Platforms like m68k can't allocate sys_off handler dynamically
+	 * at the early boot time because memory allocator isn't available yet.
+	 */
+	if (priority == SYS_OFF_PRIO_PLATFORM) {
+		handler = &platform_sys_off_handler;
+		if (handler->cb_data)
+			return ERR_PTR(-EBUSY);
+	} else {
+		if (system_state > SYSTEM_RUNNING)
+			flags = GFP_ATOMIC;
+		else
+			flags = GFP_KERNEL;
+
+		handler = kzalloc(sizeof(*handler), flags);
+		if (!handler)
+			return ERR_PTR(-ENOMEM);
+	}
+
+	return handler;
+}
+
+static void free_sys_off_handler(struct sys_off_handler *handler)
+{
+	if (handler == &platform_sys_off_handler)
+		memset(handler, 0, sizeof(*handler));
+	else
+		kfree(handler);
+}
+
+/**
+ *	register_sys_off_handler - Register sys-off handler
+ *	@mode: Sys-off mode
+ *	@priority: Handler priority
+ *	@callback: Callback function
+ *	@cb_data: Callback argument
+ *
+ *	Registers system power-off or restart handler that will be invoked
+ *	at the step corresponding to the given sys-off mode. Handler's callback
+ *	should return NOTIFY_DONE to permit execution of the next handler in
+ *	the call chain or NOTIFY_STOP to break the chain (in error case for
+ *	example).
+ *
+ *	Multiple handlers can be registered at the default priority level.
+ *
+ *	Only one handler can be registered at the non-default priority level,
+ *	otherwise ERR_PTR(-EBUSY) is returned.
+ *
+ *	Returns a new instance of struct sys_off_handler on success, or
+ *	an ERR_PTR()-encoded error code otherwise.
+ */
+struct sys_off_handler *
+register_sys_off_handler(enum sys_off_mode mode,
+			 int priority,
+			 int (*callback)(struct sys_off_data *data),
+			 void *cb_data)
+{
+	struct sys_off_handler *handler;
+	int err;
+
+	handler = alloc_sys_off_handler(priority);
+	if (IS_ERR(handler))
+		return handler;
+
+	switch (mode) {
+	case SYS_OFF_MODE_POWER_OFF_PREPARE:
+		handler->list = &power_off_prep_handler_list;
+		handler->blocking = true;
+		break;
+
+	case SYS_OFF_MODE_POWER_OFF:
+		handler->list = &power_off_handler_list;
+		break;
+
+	case SYS_OFF_MODE_RESTART_PREPARE:
+		handler->list = &restart_prep_handler_list;
+		handler->blocking = true;
+		break;
+
+	case SYS_OFF_MODE_RESTART:
+		handler->list = &restart_handler_list;
+		break;
+
+	default:
+		free_sys_off_handler(handler);
+		return ERR_PTR(-EINVAL);
+	}
+
+	handler->nb.notifier_call = sys_off_notify;
+	handler->nb.priority = priority;
+	handler->sys_off_cb = callback;
+	handler->cb_data = cb_data;
+	handler->mode = mode;
+
+	if (handler->blocking) {
+		if (priority == SYS_OFF_PRIO_DEFAULT)
+			err = blocking_notifier_chain_register(handler->list,
+							       &handler->nb);
+		else
+			err = blocking_notifier_chain_register_unique_prio(handler->list,
+									   &handler->nb);
+	} else {
+		if (priority == SYS_OFF_PRIO_DEFAULT)
+			err = atomic_notifier_chain_register(handler->list,
+							     &handler->nb);
+		else
+			err = atomic_notifier_chain_register_unique_prio(handler->list,
+									 &handler->nb);
+	}
+
+	if (err) {
+		free_sys_off_handler(handler);
+		return ERR_PTR(err);
+	}
+
+	return handler;
+}
+EXPORT_SYMBOL_GPL(register_sys_off_handler);
+
+/**
+ *	unregister_sys_off_handler - Unregister sys-off handler
+ *	@handler: Sys-off handler
+ *
+ *	Unregisters given sys-off handler.
+ */
+void unregister_sys_off_handler(struct sys_off_handler *handler)
+{
+	int err;
+
+	if (IS_ERR_OR_NULL(handler))
+		return;
+
+	if (handler->blocking)
+		err = blocking_notifier_chain_unregister(handler->list,
+							 &handler->nb);
+	else
+		err = atomic_notifier_chain_unregister(handler->list,
+						       &handler->nb);
+
+	/* sanity check, shall never happen */
+	WARN_ON(err);
+
+	free_sys_off_handler(handler);
+}
+EXPORT_SYMBOL_GPL(unregister_sys_off_handler);
+
+static void devm_unregister_sys_off_handler(void *data)
+{
+	struct sys_off_handler *handler = data;
+
+	unregister_sys_off_handler(handler);
+}
+
+/**
+ *	devm_register_sys_off_handler - Register sys-off handler
+ *	@dev: Device that registers handler
+ *	@mode: Sys-off mode
+ *	@priority: Handler priority
+ *	@callback: Callback function
+ *	@cb_data: Callback argument
+ *
+ *	Registers resource-managed sys-off handler.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_sys_off_handler(struct device *dev,
+				  enum sys_off_mode mode,
+				  int priority,
+				  int (*callback)(struct sys_off_data *data),
+				  void *cb_data)
+{
+	struct sys_off_handler *handler;
+
+	handler = register_sys_off_handler(mode, priority, callback, cb_data);
+	if (IS_ERR(handler))
+		return PTR_ERR(handler);
+
+	return devm_add_action_or_reset(dev, devm_unregister_sys_off_handler,
+					handler);
+}
+EXPORT_SYMBOL_GPL(devm_register_sys_off_handler);
+
+/**
+ *	devm_register_power_off_handler - Register power-off handler
+ *	@dev: Device that registers callback
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed sys-off handler with a default priority
+ *	and using power-off mode.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_power_off_handler(struct device *dev,
+				    int (*callback)(struct sys_off_data *data),
+				    void *cb_data)
+{
+	return devm_register_sys_off_handler(dev,
+					     SYS_OFF_MODE_POWER_OFF,
+					     SYS_OFF_PRIO_DEFAULT,
+					     callback, cb_data);
+}
+EXPORT_SYMBOL_GPL(devm_register_power_off_handler);
+
+/**
+ *	devm_register_restart_handler - Register restart handler
+ *	@dev: Device that registers callback
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed sys-off handler with a default priority
+ *	and using restart mode.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_restart_handler(struct device *dev,
+				  int (*callback)(struct sys_off_data *data),
+				  void *cb_data)
+{
+	return devm_register_sys_off_handler(dev,
+					     SYS_OFF_MODE_RESTART,
+					     SYS_OFF_PRIO_DEFAULT,
+					     callback, cb_data);
+}
+EXPORT_SYMBOL_GPL(devm_register_restart_handler);
+
+static struct sys_off_handler *platform_power_off_handler;
+
+static int platform_power_off_notify(struct sys_off_data *data)
+{
+	void (*platform_power_power_off_cb)(void) = data->cb_data;
+
+	platform_power_power_off_cb();
+
+	return NOTIFY_DONE;
+}
+
+/**
+ *	register_platform_power_off - Register platform-level power-off callback
+ *	@power_off: Power-off callback
+ *
+ *	Registers power-off callback that will be called as last step
+ *	of the power-off sequence. This callback is expected to be invoked
+ *	for the last resort. Only one platform power-off callback is allowed
+ *	to be registered at a time.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int register_platform_power_off(void (*power_off)(void))
+{
+	struct sys_off_handler *handler;
+
+	handler = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,
+					   SYS_OFF_PRIO_PLATFORM,
+					   platform_power_off_notify,
+					   power_off);
+	if (IS_ERR(handler))
+		return PTR_ERR(handler);
+
+	platform_power_off_handler = handler;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(register_platform_power_off);
+
+/**
+ *	unregister_platform_power_off - Unregister platform-level power-off callback
+ *	@power_off: Power-off callback
+ *
+ *	Unregisters previously registered platform power-off callback.
+ */
+void unregister_platform_power_off(void (*power_off)(void))
+{
+	if (platform_power_off_handler &&
+	    platform_power_off_handler->cb_data == power_off) {
+		unregister_sys_off_handler(platform_power_off_handler);
+		platform_power_off_handler = NULL;
+	}
+}
+EXPORT_SYMBOL_GPL(unregister_platform_power_off);
+
+static int legacy_pm_power_off(struct sys_off_data *data)
+{
+	if (pm_power_off)
+		pm_power_off();
+
+	return NOTIFY_DONE;
+}
+
+static void do_kernel_power_off_prepare(void)
+{
+	blocking_notifier_call_chain(&power_off_prep_handler_list, 0, NULL);
+}
+
+/**
+ *	do_kernel_power_off - Execute kernel power-off handler call chain
+ *
+ *	Expected to be called as last step of the power-off sequence.
+ *
+ *	Powers off the system immediately if a power-off handler function has
+ *	been registered. Otherwise does nothing.
+ */
+void do_kernel_power_off(void)
+{
+	struct sys_off_handler *sys_off = NULL;
+
+	/*
+	 * Register sys-off handlers for legacy PM callback. This allows
+	 * legacy PM callbacks temporary co-exist with the new sys-off API.
+	 *
+	 * TODO: Remove legacy handlers once all legacy PM users will be
+	 *       switched to the sys-off based APIs.
+	 */
+	if (pm_power_off)
+		sys_off = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,
+						   SYS_OFF_PRIO_DEFAULT,
+						   legacy_pm_power_off, NULL);
+
+	atomic_notifier_call_chain(&power_off_handler_list, 0, NULL);
+
+	unregister_sys_off_handler(sys_off);
+}
+
+/**
+ *	kernel_can_power_off - check whether system can be powered off
+ *
+ *	Returns true if power-off handler is registered and system can be
+ *	powered off, false otherwise.
+ */
+bool kernel_can_power_off(void)
+{
+	return !atomic_notifier_call_chain_is_empty(&power_off_handler_list) ||
+		pm_power_off;
+}
+EXPORT_SYMBOL_GPL(kernel_can_power_off);
+
+/**
+ *	kernel_power_off - power_off the system
+ *
+ *	Shutdown everything and perform a clean system power_off.
+ */
+void kernel_power_off(void)
+{
+	kernel_shutdown_prepare(SYSTEM_POWER_OFF);
+	do_kernel_power_off_prepare();
+	migrate_to_reboot_cpu();
+	syscore_shutdown();
+	pr_emerg("Power down\n");
+	kmsg_dump(KMSG_DUMP_SHUTDOWN);
+	machine_power_off();
+}
+EXPORT_SYMBOL_GPL(kernel_power_off);
+
+DEFINE_MUTEX(system_transition_mutex);
+
+/*
+ * Reboot system call: for obvious reasons only root may call it,
+ * and even root needs to set up some magic numbers in the registers
+ * so that some mistake won't make this reboot the whole machine.
+ * You can also set the meaning of the ctrl-alt-del-key here.
+ *
+ * reboot doesn't sync: do that yourself before calling this.
+ */
+SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
+		void __user *, arg)
+{
+	struct pid_namespace *pid_ns = task_active_pid_ns(current);
+	char buffer[256];
+	int ret = 0;
+
+	/* We only trust the superuser with rebooting the system. */
+	if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
+		return -EPERM;
+
+	/* For safety, we require "magic" arguments. */
+	if (magic1 != LINUX_REBOOT_MAGIC1 ||
+			(magic2 != LINUX_REBOOT_MAGIC2 &&
+			magic2 != LINUX_REBOOT_MAGIC2A &&
+			magic2 != LINUX_REBOOT_MAGIC2B &&
+			magic2 != LINUX_REBOOT_MAGIC2C))
+		return -EINVAL;
+
+	/*
+	 * If pid namespaces are enabled and the current task is in a child
+	 * pid_namespace, the command is handled by reboot_pid_ns() which will
+	 * call do_exit().
+	 */
+	ret = reboot_pid_ns(pid_ns, cmd);
+	if (ret)
+		return ret;
+
+	/* Instead of trying to make the power_off code look like
+	 * halt when pm_power_off is not set do it the easy way.
+	 */
+	if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !kernel_can_power_off())
+		cmd = LINUX_REBOOT_CMD_HALT;
+
+	mutex_lock(&system_transition_mutex);
+	switch (cmd) {
+	case LINUX_REBOOT_CMD_RESTART:
+		kernel_restart(NULL);
+		break;
+
+	case LINUX_REBOOT_CMD_CAD_ON:
+		C_A_D = 1;
+		break;
+
+	case LINUX_REBOOT_CMD_CAD_OFF:
+		C_A_D = 0;
+		break;
+
+	case LINUX_REBOOT_CMD_HALT:
+		kernel_halt();
+		do_exit(0);
+
+	case LINUX_REBOOT_CMD_POWER_OFF:
+		kernel_power_off();
+		do_exit(0);
+		break;
+
+	case LINUX_REBOOT_CMD_RESTART2:
+		ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1);
+		if (ret < 0) {
+			ret = -EFAULT;
+			break;
+		}
+		buffer[sizeof(buffer) - 1] = '\0';
+
+		kernel_restart(buffer);
+		break;
+
+#ifdef CONFIG_KEXEC_CORE
+	case LINUX_REBOOT_CMD_KEXEC:
+		ret = kernel_kexec();
+		break;
+#endif
+
+#ifdef CONFIG_HIBERNATION
+	case LINUX_REBOOT_CMD_SW_SUSPEND:
+		ret = hibernate();
+		break;
+#endif
+
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	mutex_unlock(&system_transition_mutex);
+	return ret;
+}
+
+static void deferred_cad(struct work_struct *dummy)
+{
+	kernel_restart(NULL);
+}
+
+/*
+ * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
+ * As it's called within an interrupt, it may NOT sync: the only choice
+ * is whether to reboot at once, or just ignore the ctrl-alt-del.
+ */
+void ctrl_alt_del(void)
+{
+	static DECLARE_WORK(cad_work, deferred_cad);
+
+	if (C_A_D)
+		schedule_work(&cad_work);
+	else
+		kill_cad_pid(SIGINT, 1);
+}
+
+#define POWEROFF_CMD_PATH_LEN  256
+static char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
+static const char reboot_cmd[] = "/sbin/reboot";
+
+static int run_cmd(const char *cmd)
+{
+	char **argv;
+	static char *envp[] = {
+		"HOME=/",
+		"PATH=/sbin:/bin:/usr/sbin:/usr/bin",
+		NULL
+	};
+	int ret;
+	argv = argv_split(GFP_KERNEL, cmd, NULL);
+	if (argv) {
+		ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
+		argv_free(argv);
+	} else {
+		ret = -ENOMEM;
+	}
+
+	return ret;
+}
+
+static int __orderly_reboot(void)
+{
+	int ret;
+
+	ret = run_cmd(reboot_cmd);
+
+	if (ret) {
+		pr_warn("Failed to start orderly reboot: forcing the issue\n");
+		emergency_sync();
+		kernel_restart(NULL);
+	}
+
+	return ret;
+}
+
+static int __orderly_poweroff(bool force)
+{
+	int ret;
+
+	ret = run_cmd(poweroff_cmd);
+
+	if (ret && force) {
+		pr_warn("Failed to start orderly shutdown: forcing the issue\n");
+
+		/*
+		 * I guess this should try to kick off some daemon to sync and
+		 * poweroff asap.  Or not even bother syncing if we're doing an
+		 * emergency shutdown?
+		 */
+		emergency_sync();
+		kernel_power_off();
+	}
+
+	return ret;
+}
+
+static bool poweroff_force;
+
+static void poweroff_work_func(struct work_struct *work)
+{
+	__orderly_poweroff(poweroff_force);
+}
+
+static DECLARE_WORK(poweroff_work, poweroff_work_func);
+
+/**
+ * orderly_poweroff - Trigger an orderly system poweroff
+ * @force: force poweroff if command execution fails
+ *
+ * This may be called from any context to trigger a system shutdown.
+ * If the orderly shutdown fails, it will force an immediate shutdown.
+ */
+void orderly_poweroff(bool force)
+{
+	if (force) /* do not override the pending "true" */
+		poweroff_force = true;
+	schedule_work(&poweroff_work);
+}
+EXPORT_SYMBOL_GPL(orderly_poweroff);
+
+static void reboot_work_func(struct work_struct *work)
+{
+	__orderly_reboot();
+}
+
+static DECLARE_WORK(reboot_work, reboot_work_func);
+
+/**
+ * orderly_reboot - Trigger an orderly system reboot
+ *
+ * This may be called from any context to trigger a system reboot.
+ * If the orderly reboot fails, it will force an immediate reboot.
+ */
+void orderly_reboot(void)
+{
+	schedule_work(&reboot_work);
+}
+EXPORT_SYMBOL_GPL(orderly_reboot);
+
+/**
+ * hw_failure_emergency_poweroff_func - emergency poweroff work after a known delay
+ * @work: work_struct associated with the emergency poweroff function
+ *
+ * This function is called in very critical situations to force
+ * a kernel poweroff after a configurable timeout value.
+ */
+static void hw_failure_emergency_poweroff_func(struct work_struct *work)
+{
+	/*
+	 * We have reached here after the emergency shutdown waiting period has
+	 * expired. This means orderly_poweroff has not been able to shut off
+	 * the system for some reason.
+	 *
+	 * Try to shut down the system immediately using kernel_power_off
+	 * if populated
+	 */
+	pr_emerg("Hardware protection timed-out. Trying forced poweroff\n");
+	kernel_power_off();
+
+	/*
+	 * Worst of the worst case trigger emergency restart
+	 */
+	pr_emerg("Hardware protection shutdown failed. Trying emergency restart\n");
+	emergency_restart();
+}
+
+static DECLARE_DELAYED_WORK(hw_failure_emergency_poweroff_work,
+			    hw_failure_emergency_poweroff_func);
+
+/**
+ * hw_failure_emergency_poweroff - Trigger an emergency system poweroff
+ *
+ * This may be called from any critical situation to trigger a system shutdown
+ * after a given period of time. If time is negative this is not scheduled.
+ */
+static void hw_failure_emergency_poweroff(int poweroff_delay_ms)
+{
+	if (poweroff_delay_ms <= 0)
+		return;
+	schedule_delayed_work(&hw_failure_emergency_poweroff_work,
+			      msecs_to_jiffies(poweroff_delay_ms));
+}
+
+/**
+ * hw_protection_shutdown - Trigger an emergency system poweroff
+ *
+ * @reason:		Reason of emergency shutdown to be printed.
+ * @ms_until_forced:	Time to wait for orderly shutdown before tiggering a
+ *			forced shudown. Negative value disables the forced
+ *			shutdown.
+ *
+ * Initiate an emergency system shutdown in order to protect hardware from
+ * further damage. Usage examples include a thermal protection or a voltage or
+ * current regulator failures.
+ * NOTE: The request is ignored if protection shutdown is already pending even
+ * if the previous request has given a large timeout for forced shutdown.
+ * Can be called from any context.
+ */
+void hw_protection_shutdown(const char *reason, int ms_until_forced)
+{
+	static atomic_t allow_proceed = ATOMIC_INIT(1);
+
+	pr_emerg("HARDWARE PROTECTION shutdown (%s)\n", reason);
+
+	/* Shutdown should be initiated only once. */
+	if (!atomic_dec_and_test(&allow_proceed))
+		return;
+
+	/*
+	 * Queue a backup emergency shutdown in the event of
+	 * orderly_poweroff failure
+	 */
+	hw_failure_emergency_poweroff(ms_until_forced);
+	orderly_poweroff(true);
+}
+EXPORT_SYMBOL_GPL(hw_protection_shutdown);
+
+static int __init reboot_setup(char *str)
+{
+	for (;;) {
+		enum reboot_mode *mode;
+
+		/*
+		 * Having anything passed on the command line via
+		 * reboot= will cause us to disable DMI checking
+		 * below.
+		 */
+		reboot_default = 0;
+
+		if (!strncmp(str, "panic_", 6)) {
+			mode = &panic_reboot_mode;
+			str += 6;
+		} else {
+			mode = &reboot_mode;
+		}
+
+		switch (*str) {
+		case 'w':
+			*mode = REBOOT_WARM;
+			break;
+
+		case 'c':
+			*mode = REBOOT_COLD;
+			break;
+
+		case 'h':
+			*mode = REBOOT_HARD;
+			break;
+
+		case 's':
+			/*
+			 * reboot_cpu is s[mp]#### with #### being the processor
+			 * to be used for rebooting. Skip 's' or 'smp' prefix.
+			 */
+			str += str[1] == 'm' && str[2] == 'p' ? 3 : 1;
+
+			if (isdigit(str[0])) {
+				int cpu = simple_strtoul(str, NULL, 0);
+
+				if (cpu >= num_possible_cpus()) {
+					pr_err("Ignoring the CPU number in reboot= option. "
+					"CPU %d exceeds possible cpu number %d\n",
+					cpu, num_possible_cpus());
+					break;
+				}
+				reboot_cpu = cpu;
+			} else
+				*mode = REBOOT_SOFT;
+			break;
+
+		case 'g':
+			*mode = REBOOT_GPIO;
+			break;
+
+		case 'b':
+		case 'a':
+		case 'k':
+		case 't':
+		case 'e':
+		case 'p':
+			reboot_type = *str;
+			break;
+
+		case 'f':
+			reboot_force = 1;
+			break;
+		}
+
+		str = strchr(str, ',');
+		if (str)
+			str++;
+		else
+			break;
+	}
+	return 1;
+}
+__setup("reboot=", reboot_setup);
+
+#ifdef CONFIG_SYSFS
+
+#define REBOOT_COLD_STR		"cold"
+#define REBOOT_WARM_STR		"warm"
+#define REBOOT_HARD_STR		"hard"
+#define REBOOT_SOFT_STR		"soft"
+#define REBOOT_GPIO_STR		"gpio"
+#define REBOOT_UNDEFINED_STR	"undefined"
+
+#define BOOT_TRIPLE_STR		"triple"
+#define BOOT_KBD_STR		"kbd"
+#define BOOT_BIOS_STR		"bios"
+#define BOOT_ACPI_STR		"acpi"
+#define BOOT_EFI_STR		"efi"
+#define BOOT_PCI_STR		"pci"
+
+static ssize_t mode_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	const char *val;
+
+	switch (reboot_mode) {
+	case REBOOT_COLD:
+		val = REBOOT_COLD_STR;
+		break;
+	case REBOOT_WARM:
+		val = REBOOT_WARM_STR;
+		break;
+	case REBOOT_HARD:
+		val = REBOOT_HARD_STR;
+		break;
+	case REBOOT_SOFT:
+		val = REBOOT_SOFT_STR;
+		break;
+	case REBOOT_GPIO:
+		val = REBOOT_GPIO_STR;
+		break;
+	default:
+		val = REBOOT_UNDEFINED_STR;
+	}
+
+	return sprintf(buf, "%s\n", val);
+}
+static ssize_t mode_store(struct kobject *kobj, struct kobj_attribute *attr,
+			  const char *buf, size_t count)
+{
+	if (!capable(CAP_SYS_BOOT))
+		return -EPERM;
+
+	if (!strncmp(buf, REBOOT_COLD_STR, strlen(REBOOT_COLD_STR)))
+		reboot_mode = REBOOT_COLD;
+	else if (!strncmp(buf, REBOOT_WARM_STR, strlen(REBOOT_WARM_STR)))
+		reboot_mode = REBOOT_WARM;
+	else if (!strncmp(buf, REBOOT_HARD_STR, strlen(REBOOT_HARD_STR)))
+		reboot_mode = REBOOT_HARD;
+	else if (!strncmp(buf, REBOOT_SOFT_STR, strlen(REBOOT_SOFT_STR)))
+		reboot_mode = REBOOT_SOFT;
+	else if (!strncmp(buf, REBOOT_GPIO_STR, strlen(REBOOT_GPIO_STR)))
+		reboot_mode = REBOOT_GPIO;
+	else
+		return -EINVAL;
+
+	reboot_default = 0;
+
+	return count;
+}
+static struct kobj_attribute reboot_mode_attr = __ATTR_RW(mode);
+
+#ifdef CONFIG_X86
+static ssize_t force_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", reboot_force);
+}
+static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
+			  const char *buf, size_t count)
+{
+	bool res;
+
+	if (!capable(CAP_SYS_BOOT))
+		return -EPERM;
+
+	if (kstrtobool(buf, &res))
+		return -EINVAL;
+
+	reboot_default = 0;
+	reboot_force = res;
+
+	return count;
+}
+static struct kobj_attribute reboot_force_attr = __ATTR_RW(force);
+
+static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	const char *val;
+
+	switch (reboot_type) {
+	case BOOT_TRIPLE:
+		val = BOOT_TRIPLE_STR;
+		break;
+	case BOOT_KBD:
+		val = BOOT_KBD_STR;
+		break;
+	case BOOT_BIOS:
+		val = BOOT_BIOS_STR;
+		break;
+	case BOOT_ACPI:
+		val = BOOT_ACPI_STR;
+		break;
+	case BOOT_EFI:
+		val = BOOT_EFI_STR;
+		break;
+	case BOOT_CF9_FORCE:
+		val = BOOT_PCI_STR;
+		break;
+	default:
+		val = REBOOT_UNDEFINED_STR;
+	}
+
+	return sprintf(buf, "%s\n", val);
+}
+static ssize_t type_store(struct kobject *kobj, struct kobj_attribute *attr,
+			  const char *buf, size_t count)
+{
+	if (!capable(CAP_SYS_BOOT))
+		return -EPERM;
+
+	if (!strncmp(buf, BOOT_TRIPLE_STR, strlen(BOOT_TRIPLE_STR)))
+		reboot_type = BOOT_TRIPLE;
+	else if (!strncmp(buf, BOOT_KBD_STR, strlen(BOOT_KBD_STR)))
+		reboot_type = BOOT_KBD;
+	else if (!strncmp(buf, BOOT_BIOS_STR, strlen(BOOT_BIOS_STR)))
+		reboot_type = BOOT_BIOS;
+	else if (!strncmp(buf, BOOT_ACPI_STR, strlen(BOOT_ACPI_STR)))
+		reboot_type = BOOT_ACPI;
+	else if (!strncmp(buf, BOOT_EFI_STR, strlen(BOOT_EFI_STR)))
+		reboot_type = BOOT_EFI;
+	else if (!strncmp(buf, BOOT_PCI_STR, strlen(BOOT_PCI_STR)))
+		reboot_type = BOOT_CF9_FORCE;
+	else
+		return -EINVAL;
+
+	reboot_default = 0;
+
+	return count;
+}
+static struct kobj_attribute reboot_type_attr = __ATTR_RW(type);
+#endif
+
+#ifdef CONFIG_SMP
+static ssize_t cpu_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", reboot_cpu);
+}
+static ssize_t cpu_store(struct kobject *kobj, struct kobj_attribute *attr,
+			  const char *buf, size_t count)
+{
+	unsigned int cpunum;
+	int rc;
+
+	if (!capable(CAP_SYS_BOOT))
+		return -EPERM;
+
+	rc = kstrtouint(buf, 0, &cpunum);
+
+	if (rc)
+		return rc;
+
+	if (cpunum >= num_possible_cpus())
+		return -ERANGE;
+
+	reboot_default = 0;
+	reboot_cpu = cpunum;
+
+	return count;
+}
+static struct kobj_attribute reboot_cpu_attr = __ATTR_RW(cpu);
+#endif
+
+static struct attribute *reboot_attrs[] = {
+	&reboot_mode_attr.attr,
+#ifdef CONFIG_X86
+	&reboot_force_attr.attr,
+	&reboot_type_attr.attr,
+#endif
+#ifdef CONFIG_SMP
+	&reboot_cpu_attr.attr,
+#endif
+	NULL,
+};
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table kern_reboot_table[] = {
+	{
+		.procname       = "poweroff_cmd",
+		.data           = &poweroff_cmd,
+		.maxlen         = POWEROFF_CMD_PATH_LEN,
+		.mode           = 0644,
+		.proc_handler   = proc_dostring,
+	},
+	{
+		.procname       = "ctrl-alt-del",
+		.data           = &C_A_D,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec,
+	},
+	{ }
+};
+
+static void __init kernel_reboot_sysctls_init(void)
+{
+	register_sysctl_init("kernel", kern_reboot_table);
+}
+#else
+#define kernel_reboot_sysctls_init() do { } while (0)
+#endif /* CONFIG_SYSCTL */
+
+static const struct attribute_group reboot_attr_group = {
+	.attrs = reboot_attrs,
+};
+
+static int __init reboot_ksysfs_init(void)
+{
+	struct kobject *reboot_kobj;
+	int ret;
+
+	reboot_kobj = kobject_create_and_add("reboot", kernel_kobj);
+	if (!reboot_kobj)
+		return -ENOMEM;
+
+	ret = sysfs_create_group(reboot_kobj, &reboot_attr_group);
+	if (ret) {
+		kobject_put(reboot_kobj);
+		return ret;
+	}
+
+	kernel_reboot_sysctls_init();
+
+	return 0;
+}
+late_initcall(reboot_ksysfs_init);
+
+#endif
diff --git a/kernel/regset.c b/kernel/regset.c
new file mode 100644
index 000000000..586823786
--- /dev/null
+++ b/kernel/regset.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/regset.h>
+
+static int __regset_get(struct task_struct *target,
+			const struct user_regset *regset,
+			unsigned int size,
+			void **data)
+{
+	void *p = *data, *to_free = NULL;
+	int res;
+
+	if (!regset->regset_get)
+		return -EOPNOTSUPP;
+	if (size > regset->n * regset->size)
+		size = regset->n * regset->size;
+	if (!p) {
+		to_free = p = kzalloc(size, GFP_KERNEL);
+		if (!p)
+			return -ENOMEM;
+	}
+	res = regset->regset_get(target, regset,
+			   (struct membuf){.p = p, .left = size});
+	if (res < 0) {
+		kfree(to_free);
+		return res;
+	}
+	*data = p;
+	return size - res;
+}
+
+int regset_get(struct task_struct *target,
+	       const struct user_regset *regset,
+	       unsigned int size,
+	       void *data)
+{
+	return __regset_get(target, regset, size, &data);
+}
+EXPORT_SYMBOL(regset_get);
+
+int regset_get_alloc(struct task_struct *target,
+		     const struct user_regset *regset,
+		     unsigned int size,
+		     void **data)
+{
+	*data = NULL;
+	return __regset_get(target, regset, size, data);
+}
+EXPORT_SYMBOL(regset_get_alloc);
+
+/**
+ * copy_regset_to_user - fetch a thread's user_regset data into user memory
+ * @target:	thread to be examined
+ * @view:	&struct user_regset_view describing user thread machine state
+ * @setno:	index in @view->regsets
+ * @offset:	offset into the regset data, in bytes
+ * @size:	amount of data to copy, in bytes
+ * @data:	user-mode pointer to copy into
+ */
+int copy_regset_to_user(struct task_struct *target,
+			const struct user_regset_view *view,
+			unsigned int setno,
+			unsigned int offset, unsigned int size,
+			void __user *data)
+{
+	const struct user_regset *regset = &view->regsets[setno];
+	void *buf;
+	int ret;
+
+	ret = regset_get_alloc(target, regset, size, &buf);
+	if (ret > 0)
+		ret = copy_to_user(data, buf, ret) ? -EFAULT : 0;
+	kfree(buf);
+	return ret;
+}
diff --git a/kernel/relay.c b/kernel/relay.c
new file mode 100644
index 000000000..1cb4bb9f0
--- /dev/null
+++ b/kernel/relay.c
@@ -0,0 +1,1247 @@
+/*
+ * Public API and common code for kernel->userspace relay file support.
+ *
+ * See Documentation/filesystems/relay.rst for an overview.
+ *
+ * Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
+ * Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
+ *
+ * Moved to kernel/relay.c by Paul Mundt, 2006.
+ * November 2006 - CPU hotplug support by Mathieu Desnoyers
+ * 	(mathieu.desnoyers@polymtl.ca)
+ *
+ * This file is released under the GPL.
+ */
+#include <linux/errno.h>
+#include <linux/stddef.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/string.h>
+#include <linux/relay.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <linux/cpu.h>
+#include <linux/splice.h>
+
+/* list of open channels, for cpu hotplug */
+static DEFINE_MUTEX(relay_channels_mutex);
+static LIST_HEAD(relay_channels);
+
+/*
+ * fault() vm_op implementation for relay file mapping.
+ */
+static vm_fault_t relay_buf_fault(struct vm_fault *vmf)
+{
+	struct page *page;
+	struct rchan_buf *buf = vmf->vma->vm_private_data;
+	pgoff_t pgoff = vmf->pgoff;
+
+	if (!buf)
+		return VM_FAULT_OOM;
+
+	page = vmalloc_to_page(buf->start + (pgoff << PAGE_SHIFT));
+	if (!page)
+		return VM_FAULT_SIGBUS;
+	get_page(page);
+	vmf->page = page;
+
+	return 0;
+}
+
+/*
+ * vm_ops for relay file mappings.
+ */
+static const struct vm_operations_struct relay_file_mmap_ops = {
+	.fault = relay_buf_fault,
+};
+
+/*
+ * allocate an array of pointers of struct page
+ */
+static struct page **relay_alloc_page_array(unsigned int n_pages)
+{
+	return kvcalloc(n_pages, sizeof(struct page *), GFP_KERNEL);
+}
+
+/*
+ * free an array of pointers of struct page
+ */
+static void relay_free_page_array(struct page **array)
+{
+	kvfree(array);
+}
+
+/**
+ *	relay_mmap_buf: - mmap channel buffer to process address space
+ *	@buf: relay channel buffer
+ *	@vma: vm_area_struct describing memory to be mapped
+ *
+ *	Returns 0 if ok, negative on error
+ *
+ *	Caller should already have grabbed mmap_lock.
+ */
+static int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
+{
+	unsigned long length = vma->vm_end - vma->vm_start;
+
+	if (!buf)
+		return -EBADF;
+
+	if (length != (unsigned long)buf->chan->alloc_size)
+		return -EINVAL;
+
+	vma->vm_ops = &relay_file_mmap_ops;
+	vma->vm_flags |= VM_DONTEXPAND;
+	vma->vm_private_data = buf;
+
+	return 0;
+}
+
+/**
+ *	relay_alloc_buf - allocate a channel buffer
+ *	@buf: the buffer struct
+ *	@size: total size of the buffer
+ *
+ *	Returns a pointer to the resulting buffer, %NULL if unsuccessful. The
+ *	passed in size will get page aligned, if it isn't already.
+ */
+static void *relay_alloc_buf(struct rchan_buf *buf, size_t *size)
+{
+	void *mem;
+	unsigned int i, j, n_pages;
+
+	*size = PAGE_ALIGN(*size);
+	n_pages = *size >> PAGE_SHIFT;
+
+	buf->page_array = relay_alloc_page_array(n_pages);
+	if (!buf->page_array)
+		return NULL;
+
+	for (i = 0; i < n_pages; i++) {
+		buf->page_array[i] = alloc_page(GFP_KERNEL);
+		if (unlikely(!buf->page_array[i]))
+			goto depopulate;
+		set_page_private(buf->page_array[i], (unsigned long)buf);
+	}
+	mem = vmap(buf->page_array, n_pages, VM_MAP, PAGE_KERNEL);
+	if (!mem)
+		goto depopulate;
+
+	memset(mem, 0, *size);
+	buf->page_count = n_pages;
+	return mem;
+
+depopulate:
+	for (j = 0; j < i; j++)
+		__free_page(buf->page_array[j]);
+	relay_free_page_array(buf->page_array);
+	return NULL;
+}
+
+/**
+ *	relay_create_buf - allocate and initialize a channel buffer
+ *	@chan: the relay channel
+ *
+ *	Returns channel buffer if successful, %NULL otherwise.
+ */
+static struct rchan_buf *relay_create_buf(struct rchan *chan)
+{
+	struct rchan_buf *buf;
+
+	if (chan->n_subbufs > KMALLOC_MAX_SIZE / sizeof(size_t))
+		return NULL;
+
+	buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL);
+	if (!buf)
+		return NULL;
+	buf->padding = kmalloc_array(chan->n_subbufs, sizeof(size_t),
+				     GFP_KERNEL);
+	if (!buf->padding)
+		goto free_buf;
+
+	buf->start = relay_alloc_buf(buf, &chan->alloc_size);
+	if (!buf->start)
+		goto free_buf;
+
+	buf->chan = chan;
+	kref_get(&buf->chan->kref);
+	return buf;
+
+free_buf:
+	kfree(buf->padding);
+	kfree(buf);
+	return NULL;
+}
+
+/**
+ *	relay_destroy_channel - free the channel struct
+ *	@kref: target kernel reference that contains the relay channel
+ *
+ *	Should only be called from kref_put().
+ */
+static void relay_destroy_channel(struct kref *kref)
+{
+	struct rchan *chan = container_of(kref, struct rchan, kref);
+	free_percpu(chan->buf);
+	kfree(chan);
+}
+
+/**
+ *	relay_destroy_buf - destroy an rchan_buf struct and associated buffer
+ *	@buf: the buffer struct
+ */
+static void relay_destroy_buf(struct rchan_buf *buf)
+{
+	struct rchan *chan = buf->chan;
+	unsigned int i;
+
+	if (likely(buf->start)) {
+		vunmap(buf->start);
+		for (i = 0; i < buf->page_count; i++)
+			__free_page(buf->page_array[i]);
+		relay_free_page_array(buf->page_array);
+	}
+	*per_cpu_ptr(chan->buf, buf->cpu) = NULL;
+	kfree(buf->padding);
+	kfree(buf);
+	kref_put(&chan->kref, relay_destroy_channel);
+}
+
+/**
+ *	relay_remove_buf - remove a channel buffer
+ *	@kref: target kernel reference that contains the relay buffer
+ *
+ *	Removes the file from the filesystem, which also frees the
+ *	rchan_buf_struct and the channel buffer.  Should only be called from
+ *	kref_put().
+ */
+static void relay_remove_buf(struct kref *kref)
+{
+	struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref);
+	relay_destroy_buf(buf);
+}
+
+/**
+ *	relay_buf_empty - boolean, is the channel buffer empty?
+ *	@buf: channel buffer
+ *
+ *	Returns 1 if the buffer is empty, 0 otherwise.
+ */
+static int relay_buf_empty(struct rchan_buf *buf)
+{
+	return (buf->subbufs_produced - buf->subbufs_consumed) ? 0 : 1;
+}
+
+/**
+ *	relay_buf_full - boolean, is the channel buffer full?
+ *	@buf: channel buffer
+ *
+ *	Returns 1 if the buffer is full, 0 otherwise.
+ */
+int relay_buf_full(struct rchan_buf *buf)
+{
+	size_t ready = buf->subbufs_produced - buf->subbufs_consumed;
+	return (ready >= buf->chan->n_subbufs) ? 1 : 0;
+}
+EXPORT_SYMBOL_GPL(relay_buf_full);
+
+/*
+ * High-level relay kernel API and associated functions.
+ */
+
+static int relay_subbuf_start(struct rchan_buf *buf, void *subbuf,
+			      void *prev_subbuf, size_t prev_padding)
+{
+	if (!buf->chan->cb->subbuf_start)
+		return !relay_buf_full(buf);
+
+	return buf->chan->cb->subbuf_start(buf, subbuf,
+					   prev_subbuf, prev_padding);
+}
+
+/**
+ *	wakeup_readers - wake up readers waiting on a channel
+ *	@work: contains the channel buffer
+ *
+ *	This is the function used to defer reader waking
+ */
+static void wakeup_readers(struct irq_work *work)
+{
+	struct rchan_buf *buf;
+
+	buf = container_of(work, struct rchan_buf, wakeup_work);
+	wake_up_interruptible(&buf->read_wait);
+}
+
+/**
+ *	__relay_reset - reset a channel buffer
+ *	@buf: the channel buffer
+ *	@init: 1 if this is a first-time initialization
+ *
+ *	See relay_reset() for description of effect.
+ */
+static void __relay_reset(struct rchan_buf *buf, unsigned int init)
+{
+	size_t i;
+
+	if (init) {
+		init_waitqueue_head(&buf->read_wait);
+		kref_init(&buf->kref);
+		init_irq_work(&buf->wakeup_work, wakeup_readers);
+	} else {
+		irq_work_sync(&buf->wakeup_work);
+	}
+
+	buf->subbufs_produced = 0;
+	buf->subbufs_consumed = 0;
+	buf->bytes_consumed = 0;
+	buf->finalized = 0;
+	buf->data = buf->start;
+	buf->offset = 0;
+
+	for (i = 0; i < buf->chan->n_subbufs; i++)
+		buf->padding[i] = 0;
+
+	relay_subbuf_start(buf, buf->data, NULL, 0);
+}
+
+/**
+ *	relay_reset - reset the channel
+ *	@chan: the channel
+ *
+ *	This has the effect of erasing all data from all channel buffers
+ *	and restarting the channel in its initial state.  The buffers
+ *	are not freed, so any mappings are still in effect.
+ *
+ *	NOTE. Care should be taken that the channel isn't actually
+ *	being used by anything when this call is made.
+ */
+void relay_reset(struct rchan *chan)
+{
+	struct rchan_buf *buf;
+	unsigned int i;
+
+	if (!chan)
+		return;
+
+	if (chan->is_global && (buf = *per_cpu_ptr(chan->buf, 0))) {
+		__relay_reset(buf, 0);
+		return;
+	}
+
+	mutex_lock(&relay_channels_mutex);
+	for_each_possible_cpu(i)
+		if ((buf = *per_cpu_ptr(chan->buf, i)))
+			__relay_reset(buf, 0);
+	mutex_unlock(&relay_channels_mutex);
+}
+EXPORT_SYMBOL_GPL(relay_reset);
+
+static inline void relay_set_buf_dentry(struct rchan_buf *buf,
+					struct dentry *dentry)
+{
+	buf->dentry = dentry;
+	d_inode(buf->dentry)->i_size = buf->early_bytes;
+}
+
+static struct dentry *relay_create_buf_file(struct rchan *chan,
+					    struct rchan_buf *buf,
+					    unsigned int cpu)
+{
+	struct dentry *dentry;
+	char *tmpname;
+
+	tmpname = kzalloc(NAME_MAX + 1, GFP_KERNEL);
+	if (!tmpname)
+		return NULL;
+	snprintf(tmpname, NAME_MAX, "%s%d", chan->base_filename, cpu);
+
+	/* Create file in fs */
+	dentry = chan->cb->create_buf_file(tmpname, chan->parent,
+					   S_IRUSR, buf,
+					   &chan->is_global);
+	if (IS_ERR(dentry))
+		dentry = NULL;
+
+	kfree(tmpname);
+
+	return dentry;
+}
+
+/*
+ *	relay_open_buf - create a new relay channel buffer
+ *
+ *	used by relay_open() and CPU hotplug.
+ */
+static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu)
+{
+ 	struct rchan_buf *buf = NULL;
+	struct dentry *dentry;
+
+ 	if (chan->is_global)
+		return *per_cpu_ptr(chan->buf, 0);
+
+	buf = relay_create_buf(chan);
+	if (!buf)
+		return NULL;
+
+	if (chan->has_base_filename) {
+		dentry = relay_create_buf_file(chan, buf, cpu);
+		if (!dentry)
+			goto free_buf;
+		relay_set_buf_dentry(buf, dentry);
+	} else {
+		/* Only retrieve global info, nothing more, nothing less */
+		dentry = chan->cb->create_buf_file(NULL, NULL,
+						   S_IRUSR, buf,
+						   &chan->is_global);
+		if (IS_ERR_OR_NULL(dentry))
+			goto free_buf;
+	}
+
+ 	buf->cpu = cpu;
+ 	__relay_reset(buf, 1);
+
+ 	if(chan->is_global) {
+		*per_cpu_ptr(chan->buf, 0) = buf;
+ 		buf->cpu = 0;
+  	}
+
+	return buf;
+
+free_buf:
+ 	relay_destroy_buf(buf);
+	return NULL;
+}
+
+/**
+ *	relay_close_buf - close a channel buffer
+ *	@buf: channel buffer
+ *
+ *	Marks the buffer finalized and restores the default callbacks.
+ *	The channel buffer and channel buffer data structure are then freed
+ *	automatically when the last reference is given up.
+ */
+static void relay_close_buf(struct rchan_buf *buf)
+{
+	buf->finalized = 1;
+	irq_work_sync(&buf->wakeup_work);
+	buf->chan->cb->remove_buf_file(buf->dentry);
+	kref_put(&buf->kref, relay_remove_buf);
+}
+
+int relay_prepare_cpu(unsigned int cpu)
+{
+	struct rchan *chan;
+	struct rchan_buf *buf;
+
+	mutex_lock(&relay_channels_mutex);
+	list_for_each_entry(chan, &relay_channels, list) {
+		if (*per_cpu_ptr(chan->buf, cpu))
+			continue;
+		buf = relay_open_buf(chan, cpu);
+		if (!buf) {
+			pr_err("relay: cpu %d buffer creation failed\n", cpu);
+			mutex_unlock(&relay_channels_mutex);
+			return -ENOMEM;
+		}
+		*per_cpu_ptr(chan->buf, cpu) = buf;
+	}
+	mutex_unlock(&relay_channels_mutex);
+	return 0;
+}
+
+/**
+ *	relay_open - create a new relay channel
+ *	@base_filename: base name of files to create, %NULL for buffering only
+ *	@parent: dentry of parent directory, %NULL for root directory or buffer
+ *	@subbuf_size: size of sub-buffers
+ *	@n_subbufs: number of sub-buffers
+ *	@cb: client callback functions
+ *	@private_data: user-defined data
+ *
+ *	Returns channel pointer if successful, %NULL otherwise.
+ *
+ *	Creates a channel buffer for each cpu using the sizes and
+ *	attributes specified.  The created channel buffer files
+ *	will be named base_filename0...base_filenameN-1.  File
+ *	permissions will be %S_IRUSR.
+ *
+ *	If opening a buffer (@parent = NULL) that you later wish to register
+ *	in a filesystem, call relay_late_setup_files() once the @parent dentry
+ *	is available.
+ */
+struct rchan *relay_open(const char *base_filename,
+			 struct dentry *parent,
+			 size_t subbuf_size,
+			 size_t n_subbufs,
+			 const struct rchan_callbacks *cb,
+			 void *private_data)
+{
+	unsigned int i;
+	struct rchan *chan;
+	struct rchan_buf *buf;
+
+	if (!(subbuf_size && n_subbufs))
+		return NULL;
+	if (subbuf_size > UINT_MAX / n_subbufs)
+		return NULL;
+	if (!cb || !cb->create_buf_file || !cb->remove_buf_file)
+		return NULL;
+
+	chan = kzalloc(sizeof(struct rchan), GFP_KERNEL);
+	if (!chan)
+		return NULL;
+
+	chan->buf = alloc_percpu(struct rchan_buf *);
+	if (!chan->buf) {
+		kfree(chan);
+		return NULL;
+	}
+
+	chan->version = RELAYFS_CHANNEL_VERSION;
+	chan->n_subbufs = n_subbufs;
+	chan->subbuf_size = subbuf_size;
+	chan->alloc_size = PAGE_ALIGN(subbuf_size * n_subbufs);
+	chan->parent = parent;
+	chan->private_data = private_data;
+	if (base_filename) {
+		chan->has_base_filename = 1;
+		strlcpy(chan->base_filename, base_filename, NAME_MAX);
+	}
+	chan->cb = cb;
+	kref_init(&chan->kref);
+
+	mutex_lock(&relay_channels_mutex);
+	for_each_online_cpu(i) {
+		buf = relay_open_buf(chan, i);
+		if (!buf)
+			goto free_bufs;
+		*per_cpu_ptr(chan->buf, i) = buf;
+	}
+	list_add(&chan->list, &relay_channels);
+	mutex_unlock(&relay_channels_mutex);
+
+	return chan;
+
+free_bufs:
+	for_each_possible_cpu(i) {
+		if ((buf = *per_cpu_ptr(chan->buf, i)))
+			relay_close_buf(buf);
+	}
+
+	kref_put(&chan->kref, relay_destroy_channel);
+	mutex_unlock(&relay_channels_mutex);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(relay_open);
+
+struct rchan_percpu_buf_dispatcher {
+	struct rchan_buf *buf;
+	struct dentry *dentry;
+};
+
+/* Called in atomic context. */
+static void __relay_set_buf_dentry(void *info)
+{
+	struct rchan_percpu_buf_dispatcher *p = info;
+
+	relay_set_buf_dentry(p->buf, p->dentry);
+}
+
+/**
+ *	relay_late_setup_files - triggers file creation
+ *	@chan: channel to operate on
+ *	@base_filename: base name of files to create
+ *	@parent: dentry of parent directory, %NULL for root directory
+ *
+ *	Returns 0 if successful, non-zero otherwise.
+ *
+ *	Use to setup files for a previously buffer-only channel created
+ *	by relay_open() with a NULL parent dentry.
+ *
+ *	For example, this is useful for perfomring early tracing in kernel,
+ *	before VFS is up and then exposing the early results once the dentry
+ *	is available.
+ */
+int relay_late_setup_files(struct rchan *chan,
+			   const char *base_filename,
+			   struct dentry *parent)
+{
+	int err = 0;
+	unsigned int i, curr_cpu;
+	unsigned long flags;
+	struct dentry *dentry;
+	struct rchan_buf *buf;
+	struct rchan_percpu_buf_dispatcher disp;
+
+	if (!chan || !base_filename)
+		return -EINVAL;
+
+	strlcpy(chan->base_filename, base_filename, NAME_MAX);
+
+	mutex_lock(&relay_channels_mutex);
+	/* Is chan already set up? */
+	if (unlikely(chan->has_base_filename)) {
+		mutex_unlock(&relay_channels_mutex);
+		return -EEXIST;
+	}
+	chan->has_base_filename = 1;
+	chan->parent = parent;
+
+	if (chan->is_global) {
+		err = -EINVAL;
+		buf = *per_cpu_ptr(chan->buf, 0);
+		if (!WARN_ON_ONCE(!buf)) {
+			dentry = relay_create_buf_file(chan, buf, 0);
+			if (dentry && !WARN_ON_ONCE(!chan->is_global)) {
+				relay_set_buf_dentry(buf, dentry);
+				err = 0;
+			}
+		}
+		mutex_unlock(&relay_channels_mutex);
+		return err;
+	}
+
+	curr_cpu = get_cpu();
+	/*
+	 * The CPU hotplug notifier ran before us and created buffers with
+	 * no files associated. So it's safe to call relay_setup_buf_file()
+	 * on all currently online CPUs.
+	 */
+	for_each_online_cpu(i) {
+		buf = *per_cpu_ptr(chan->buf, i);
+		if (unlikely(!buf)) {
+			WARN_ONCE(1, KERN_ERR "CPU has no buffer!\n");
+			err = -EINVAL;
+			break;
+		}
+
+		dentry = relay_create_buf_file(chan, buf, i);
+		if (unlikely(!dentry)) {
+			err = -EINVAL;
+			break;
+		}
+
+		if (curr_cpu == i) {
+			local_irq_save(flags);
+			relay_set_buf_dentry(buf, dentry);
+			local_irq_restore(flags);
+		} else {
+			disp.buf = buf;
+			disp.dentry = dentry;
+			smp_mb();
+			/* relay_channels_mutex must be held, so wait. */
+			err = smp_call_function_single(i,
+						       __relay_set_buf_dentry,
+						       &disp, 1);
+		}
+		if (unlikely(err))
+			break;
+	}
+	put_cpu();
+	mutex_unlock(&relay_channels_mutex);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(relay_late_setup_files);
+
+/**
+ *	relay_switch_subbuf - switch to a new sub-buffer
+ *	@buf: channel buffer
+ *	@length: size of current event
+ *
+ *	Returns either the length passed in or 0 if full.
+ *
+ *	Performs sub-buffer-switch tasks such as invoking callbacks,
+ *	updating padding counts, waking up readers, etc.
+ */
+size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length)
+{
+	void *old, *new;
+	size_t old_subbuf, new_subbuf;
+
+	if (unlikely(length > buf->chan->subbuf_size))
+		goto toobig;
+
+	if (buf->offset != buf->chan->subbuf_size + 1) {
+		buf->prev_padding = buf->chan->subbuf_size - buf->offset;
+		old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
+		buf->padding[old_subbuf] = buf->prev_padding;
+		buf->subbufs_produced++;
+		if (buf->dentry)
+			d_inode(buf->dentry)->i_size +=
+				buf->chan->subbuf_size -
+				buf->padding[old_subbuf];
+		else
+			buf->early_bytes += buf->chan->subbuf_size -
+					    buf->padding[old_subbuf];
+		smp_mb();
+		if (waitqueue_active(&buf->read_wait)) {
+			/*
+			 * Calling wake_up_interruptible() from here
+			 * will deadlock if we happen to be logging
+			 * from the scheduler (trying to re-grab
+			 * rq->lock), so defer it.
+			 */
+			irq_work_queue(&buf->wakeup_work);
+		}
+	}
+
+	old = buf->data;
+	new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
+	new = buf->start + new_subbuf * buf->chan->subbuf_size;
+	buf->offset = 0;
+	if (!relay_subbuf_start(buf, new, old, buf->prev_padding)) {
+		buf->offset = buf->chan->subbuf_size + 1;
+		return 0;
+	}
+	buf->data = new;
+	buf->padding[new_subbuf] = 0;
+
+	if (unlikely(length + buf->offset > buf->chan->subbuf_size))
+		goto toobig;
+
+	return length;
+
+toobig:
+	buf->chan->last_toobig = length;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(relay_switch_subbuf);
+
+/**
+ *	relay_subbufs_consumed - update the buffer's sub-buffers-consumed count
+ *	@chan: the channel
+ *	@cpu: the cpu associated with the channel buffer to update
+ *	@subbufs_consumed: number of sub-buffers to add to current buf's count
+ *
+ *	Adds to the channel buffer's consumed sub-buffer count.
+ *	subbufs_consumed should be the number of sub-buffers newly consumed,
+ *	not the total consumed.
+ *
+ *	NOTE. Kernel clients don't need to call this function if the channel
+ *	mode is 'overwrite'.
+ */
+void relay_subbufs_consumed(struct rchan *chan,
+			    unsigned int cpu,
+			    size_t subbufs_consumed)
+{
+	struct rchan_buf *buf;
+
+	if (!chan || cpu >= NR_CPUS)
+		return;
+
+	buf = *per_cpu_ptr(chan->buf, cpu);
+	if (!buf || subbufs_consumed > chan->n_subbufs)
+		return;
+
+	if (subbufs_consumed > buf->subbufs_produced - buf->subbufs_consumed)
+		buf->subbufs_consumed = buf->subbufs_produced;
+	else
+		buf->subbufs_consumed += subbufs_consumed;
+}
+EXPORT_SYMBOL_GPL(relay_subbufs_consumed);
+
+/**
+ *	relay_close - close the channel
+ *	@chan: the channel
+ *
+ *	Closes all channel buffers and frees the channel.
+ */
+void relay_close(struct rchan *chan)
+{
+	struct rchan_buf *buf;
+	unsigned int i;
+
+	if (!chan)
+		return;
+
+	mutex_lock(&relay_channels_mutex);
+	if (chan->is_global && (buf = *per_cpu_ptr(chan->buf, 0)))
+		relay_close_buf(buf);
+	else
+		for_each_possible_cpu(i)
+			if ((buf = *per_cpu_ptr(chan->buf, i)))
+				relay_close_buf(buf);
+
+	if (chan->last_toobig)
+		printk(KERN_WARNING "relay: one or more items not logged "
+		       "[item size (%zd) > sub-buffer size (%zd)]\n",
+		       chan->last_toobig, chan->subbuf_size);
+
+	list_del(&chan->list);
+	kref_put(&chan->kref, relay_destroy_channel);
+	mutex_unlock(&relay_channels_mutex);
+}
+EXPORT_SYMBOL_GPL(relay_close);
+
+/**
+ *	relay_flush - close the channel
+ *	@chan: the channel
+ *
+ *	Flushes all channel buffers, i.e. forces buffer switch.
+ */
+void relay_flush(struct rchan *chan)
+{
+	struct rchan_buf *buf;
+	unsigned int i;
+
+	if (!chan)
+		return;
+
+	if (chan->is_global && (buf = *per_cpu_ptr(chan->buf, 0))) {
+		relay_switch_subbuf(buf, 0);
+		return;
+	}
+
+	mutex_lock(&relay_channels_mutex);
+	for_each_possible_cpu(i)
+		if ((buf = *per_cpu_ptr(chan->buf, i)))
+			relay_switch_subbuf(buf, 0);
+	mutex_unlock(&relay_channels_mutex);
+}
+EXPORT_SYMBOL_GPL(relay_flush);
+
+/**
+ *	relay_file_open - open file op for relay files
+ *	@inode: the inode
+ *	@filp: the file
+ *
+ *	Increments the channel buffer refcount.
+ */
+static int relay_file_open(struct inode *inode, struct file *filp)
+{
+	struct rchan_buf *buf = inode->i_private;
+	kref_get(&buf->kref);
+	filp->private_data = buf;
+
+	return nonseekable_open(inode, filp);
+}
+
+/**
+ *	relay_file_mmap - mmap file op for relay files
+ *	@filp: the file
+ *	@vma: the vma describing what to map
+ *
+ *	Calls upon relay_mmap_buf() to map the file into user space.
+ */
+static int relay_file_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	struct rchan_buf *buf = filp->private_data;
+	return relay_mmap_buf(buf, vma);
+}
+
+/**
+ *	relay_file_poll - poll file op for relay files
+ *	@filp: the file
+ *	@wait: poll table
+ *
+ *	Poll implemention.
+ */
+static __poll_t relay_file_poll(struct file *filp, poll_table *wait)
+{
+	__poll_t mask = 0;
+	struct rchan_buf *buf = filp->private_data;
+
+	if (buf->finalized)
+		return EPOLLERR;
+
+	if (filp->f_mode & FMODE_READ) {
+		poll_wait(filp, &buf->read_wait, wait);
+		if (!relay_buf_empty(buf))
+			mask |= EPOLLIN | EPOLLRDNORM;
+	}
+
+	return mask;
+}
+
+/**
+ *	relay_file_release - release file op for relay files
+ *	@inode: the inode
+ *	@filp: the file
+ *
+ *	Decrements the channel refcount, as the filesystem is
+ *	no longer using it.
+ */
+static int relay_file_release(struct inode *inode, struct file *filp)
+{
+	struct rchan_buf *buf = filp->private_data;
+	kref_put(&buf->kref, relay_remove_buf);
+
+	return 0;
+}
+
+/*
+ *	relay_file_read_consume - update the consumed count for the buffer
+ */
+static void relay_file_read_consume(struct rchan_buf *buf,
+				    size_t read_pos,
+				    size_t bytes_consumed)
+{
+	size_t subbuf_size = buf->chan->subbuf_size;
+	size_t n_subbufs = buf->chan->n_subbufs;
+	size_t read_subbuf;
+
+	if (buf->subbufs_produced == buf->subbufs_consumed &&
+	    buf->offset == buf->bytes_consumed)
+		return;
+
+	if (buf->bytes_consumed + bytes_consumed > subbuf_size) {
+		relay_subbufs_consumed(buf->chan, buf->cpu, 1);
+		buf->bytes_consumed = 0;
+	}
+
+	buf->bytes_consumed += bytes_consumed;
+	if (!read_pos)
+		read_subbuf = buf->subbufs_consumed % n_subbufs;
+	else
+		read_subbuf = read_pos / buf->chan->subbuf_size;
+	if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) {
+		if ((read_subbuf == buf->subbufs_produced % n_subbufs) &&
+		    (buf->offset == subbuf_size))
+			return;
+		relay_subbufs_consumed(buf->chan, buf->cpu, 1);
+		buf->bytes_consumed = 0;
+	}
+}
+
+/*
+ *	relay_file_read_avail - boolean, are there unconsumed bytes available?
+ */
+static int relay_file_read_avail(struct rchan_buf *buf)
+{
+	size_t subbuf_size = buf->chan->subbuf_size;
+	size_t n_subbufs = buf->chan->n_subbufs;
+	size_t produced = buf->subbufs_produced;
+	size_t consumed;
+
+	relay_file_read_consume(buf, 0, 0);
+
+	consumed = buf->subbufs_consumed;
+
+	if (unlikely(buf->offset > subbuf_size)) {
+		if (produced == consumed)
+			return 0;
+		return 1;
+	}
+
+	if (unlikely(produced - consumed >= n_subbufs)) {
+		consumed = produced - n_subbufs + 1;
+		buf->subbufs_consumed = consumed;
+		buf->bytes_consumed = 0;
+	}
+
+	produced = (produced % n_subbufs) * subbuf_size + buf->offset;
+	consumed = (consumed % n_subbufs) * subbuf_size + buf->bytes_consumed;
+
+	if (consumed > produced)
+		produced += n_subbufs * subbuf_size;
+
+	if (consumed == produced) {
+		if (buf->offset == subbuf_size &&
+		    buf->subbufs_produced > buf->subbufs_consumed)
+			return 1;
+		return 0;
+	}
+
+	return 1;
+}
+
+/**
+ *	relay_file_read_subbuf_avail - return bytes available in sub-buffer
+ *	@read_pos: file read position
+ *	@buf: relay channel buffer
+ */
+static size_t relay_file_read_subbuf_avail(size_t read_pos,
+					   struct rchan_buf *buf)
+{
+	size_t padding, avail = 0;
+	size_t read_subbuf, read_offset, write_subbuf, write_offset;
+	size_t subbuf_size = buf->chan->subbuf_size;
+
+	write_subbuf = (buf->data - buf->start) / subbuf_size;
+	write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
+	read_subbuf = read_pos / subbuf_size;
+	read_offset = read_pos % subbuf_size;
+	padding = buf->padding[read_subbuf];
+
+	if (read_subbuf == write_subbuf) {
+		if (read_offset + padding < write_offset)
+			avail = write_offset - (read_offset + padding);
+	} else
+		avail = (subbuf_size - padding) - read_offset;
+
+	return avail;
+}
+
+/**
+ *	relay_file_read_start_pos - find the first available byte to read
+ *	@buf: relay channel buffer
+ *
+ *	If the read_pos is in the middle of padding, return the
+ *	position of the first actually available byte, otherwise
+ *	return the original value.
+ */
+static size_t relay_file_read_start_pos(struct rchan_buf *buf)
+{
+	size_t read_subbuf, padding, padding_start, padding_end;
+	size_t subbuf_size = buf->chan->subbuf_size;
+	size_t n_subbufs = buf->chan->n_subbufs;
+	size_t consumed = buf->subbufs_consumed % n_subbufs;
+	size_t read_pos = (consumed * subbuf_size + buf->bytes_consumed)
+			% (n_subbufs * subbuf_size);
+
+	read_subbuf = read_pos / subbuf_size;
+	padding = buf->padding[read_subbuf];
+	padding_start = (read_subbuf + 1) * subbuf_size - padding;
+	padding_end = (read_subbuf + 1) * subbuf_size;
+	if (read_pos >= padding_start && read_pos < padding_end) {
+		read_subbuf = (read_subbuf + 1) % n_subbufs;
+		read_pos = read_subbuf * subbuf_size;
+	}
+
+	return read_pos;
+}
+
+/**
+ *	relay_file_read_end_pos - return the new read position
+ *	@read_pos: file read position
+ *	@buf: relay channel buffer
+ *	@count: number of bytes to be read
+ */
+static size_t relay_file_read_end_pos(struct rchan_buf *buf,
+				      size_t read_pos,
+				      size_t count)
+{
+	size_t read_subbuf, padding, end_pos;
+	size_t subbuf_size = buf->chan->subbuf_size;
+	size_t n_subbufs = buf->chan->n_subbufs;
+
+	read_subbuf = read_pos / subbuf_size;
+	padding = buf->padding[read_subbuf];
+	if (read_pos % subbuf_size + count + padding == subbuf_size)
+		end_pos = (read_subbuf + 1) * subbuf_size;
+	else
+		end_pos = read_pos + count;
+	if (end_pos >= subbuf_size * n_subbufs)
+		end_pos = 0;
+
+	return end_pos;
+}
+
+static ssize_t relay_file_read(struct file *filp,
+			       char __user *buffer,
+			       size_t count,
+			       loff_t *ppos)
+{
+	struct rchan_buf *buf = filp->private_data;
+	size_t read_start, avail;
+	size_t written = 0;
+	int ret;
+
+	if (!count)
+		return 0;
+
+	inode_lock(file_inode(filp));
+	do {
+		void *from;
+
+		if (!relay_file_read_avail(buf))
+			break;
+
+		read_start = relay_file_read_start_pos(buf);
+		avail = relay_file_read_subbuf_avail(read_start, buf);
+		if (!avail)
+			break;
+
+		avail = min(count, avail);
+		from = buf->start + read_start;
+		ret = avail;
+		if (copy_to_user(buffer, from, avail))
+			break;
+
+		buffer += ret;
+		written += ret;
+		count -= ret;
+
+		relay_file_read_consume(buf, read_start, ret);
+		*ppos = relay_file_read_end_pos(buf, read_start, ret);
+	} while (count);
+	inode_unlock(file_inode(filp));
+
+	return written;
+}
+
+static void relay_consume_bytes(struct rchan_buf *rbuf, int bytes_consumed)
+{
+	rbuf->bytes_consumed += bytes_consumed;
+
+	if (rbuf->bytes_consumed >= rbuf->chan->subbuf_size) {
+		relay_subbufs_consumed(rbuf->chan, rbuf->cpu, 1);
+		rbuf->bytes_consumed %= rbuf->chan->subbuf_size;
+	}
+}
+
+static void relay_pipe_buf_release(struct pipe_inode_info *pipe,
+				   struct pipe_buffer *buf)
+{
+	struct rchan_buf *rbuf;
+
+	rbuf = (struct rchan_buf *)page_private(buf->page);
+	relay_consume_bytes(rbuf, buf->private);
+}
+
+static const struct pipe_buf_operations relay_pipe_buf_ops = {
+	.release	= relay_pipe_buf_release,
+	.try_steal	= generic_pipe_buf_try_steal,
+	.get		= generic_pipe_buf_get,
+};
+
+static void relay_page_release(struct splice_pipe_desc *spd, unsigned int i)
+{
+}
+
+/*
+ *	subbuf_splice_actor - splice up to one subbuf's worth of data
+ */
+static ssize_t subbuf_splice_actor(struct file *in,
+			       loff_t *ppos,
+			       struct pipe_inode_info *pipe,
+			       size_t len,
+			       unsigned int flags,
+			       int *nonpad_ret)
+{
+	unsigned int pidx, poff, total_len, subbuf_pages, nr_pages;
+	struct rchan_buf *rbuf = in->private_data;
+	unsigned int subbuf_size = rbuf->chan->subbuf_size;
+	uint64_t pos = (uint64_t) *ppos;
+	uint32_t alloc_size = (uint32_t) rbuf->chan->alloc_size;
+	size_t read_start = (size_t) do_div(pos, alloc_size);
+	size_t read_subbuf = read_start / subbuf_size;
+	size_t padding = rbuf->padding[read_subbuf];
+	size_t nonpad_end = read_subbuf * subbuf_size + subbuf_size - padding;
+	struct page *pages[PIPE_DEF_BUFFERS];
+	struct partial_page partial[PIPE_DEF_BUFFERS];
+	struct splice_pipe_desc spd = {
+		.pages = pages,
+		.nr_pages = 0,
+		.nr_pages_max = PIPE_DEF_BUFFERS,
+		.partial = partial,
+		.ops = &relay_pipe_buf_ops,
+		.spd_release = relay_page_release,
+	};
+	ssize_t ret;
+
+	if (rbuf->subbufs_produced == rbuf->subbufs_consumed)
+		return 0;
+	if (splice_grow_spd(pipe, &spd))
+		return -ENOMEM;
+
+	/*
+	 * Adjust read len, if longer than what is available
+	 */
+	if (len > (subbuf_size - read_start % subbuf_size))
+		len = subbuf_size - read_start % subbuf_size;
+
+	subbuf_pages = rbuf->chan->alloc_size >> PAGE_SHIFT;
+	pidx = (read_start / PAGE_SIZE) % subbuf_pages;
+	poff = read_start & ~PAGE_MASK;
+	nr_pages = min_t(unsigned int, subbuf_pages, spd.nr_pages_max);
+
+	for (total_len = 0; spd.nr_pages < nr_pages; spd.nr_pages++) {
+		unsigned int this_len, this_end, private;
+		unsigned int cur_pos = read_start + total_len;
+
+		if (!len)
+			break;
+
+		this_len = min_t(unsigned long, len, PAGE_SIZE - poff);
+		private = this_len;
+
+		spd.pages[spd.nr_pages] = rbuf->page_array[pidx];
+		spd.partial[spd.nr_pages].offset = poff;
+
+		this_end = cur_pos + this_len;
+		if (this_end >= nonpad_end) {
+			this_len = nonpad_end - cur_pos;
+			private = this_len + padding;
+		}
+		spd.partial[spd.nr_pages].len = this_len;
+		spd.partial[spd.nr_pages].private = private;
+
+		len -= this_len;
+		total_len += this_len;
+		poff = 0;
+		pidx = (pidx + 1) % subbuf_pages;
+
+		if (this_end >= nonpad_end) {
+			spd.nr_pages++;
+			break;
+		}
+	}
+
+	ret = 0;
+	if (!spd.nr_pages)
+		goto out;
+
+	ret = *nonpad_ret = splice_to_pipe(pipe, &spd);
+	if (ret < 0 || ret < total_len)
+		goto out;
+
+        if (read_start + ret == nonpad_end)
+                ret += padding;
+
+out:
+	splice_shrink_spd(&spd);
+	return ret;
+}
+
+static ssize_t relay_file_splice_read(struct file *in,
+				      loff_t *ppos,
+				      struct pipe_inode_info *pipe,
+				      size_t len,
+				      unsigned int flags)
+{
+	ssize_t spliced;
+	int ret;
+	int nonpad_ret = 0;
+
+	ret = 0;
+	spliced = 0;
+
+	while (len && !spliced) {
+		ret = subbuf_splice_actor(in, ppos, pipe, len, flags, &nonpad_ret);
+		if (ret < 0)
+			break;
+		else if (!ret) {
+			if (flags & SPLICE_F_NONBLOCK)
+				ret = -EAGAIN;
+			break;
+		}
+
+		*ppos += ret;
+		if (ret > len)
+			len = 0;
+		else
+			len -= ret;
+		spliced += nonpad_ret;
+		nonpad_ret = 0;
+	}
+
+	if (spliced)
+		return spliced;
+
+	return ret;
+}
+
+const struct file_operations relay_file_operations = {
+	.open		= relay_file_open,
+	.poll		= relay_file_poll,
+	.mmap		= relay_file_mmap,
+	.read		= relay_file_read,
+	.llseek		= no_llseek,
+	.release	= relay_file_release,
+	.splice_read	= relay_file_splice_read,
+};
+EXPORT_SYMBOL_GPL(relay_file_operations);
diff --git a/kernel/resource.c b/kernel/resource.c
new file mode 100644
index 000000000..8f52f8800
--- /dev/null
+++ b/kernel/resource.c
@@ -0,0 +1,2020 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *	linux/kernel/resource.c
+ *
+ * Copyright (C) 1999	Linus Torvalds
+ * Copyright (C) 1999	Martin Mares <mj@ucw.cz>
+ *
+ * Arbitrary resource management.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/export.h>
+#include <linux/errno.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/fs.h>
+#include <linux/proc_fs.h>
+#include <linux/pseudo_fs.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/device.h>
+#include <linux/pfn.h>
+#include <linux/mm.h>
+#include <linux/mount.h>
+#include <linux/resource_ext.h>
+#include <uapi/linux/magic.h>
+#include <asm/io.h>
+
+
+struct resource ioport_resource = {
+	.name	= "PCI IO",
+	.start	= 0,
+	.end	= IO_SPACE_LIMIT,
+	.flags	= IORESOURCE_IO,
+};
+EXPORT_SYMBOL(ioport_resource);
+
+struct resource iomem_resource = {
+	.name	= "PCI mem",
+	.start	= 0,
+	.end	= -1,
+	.flags	= IORESOURCE_MEM,
+};
+EXPORT_SYMBOL(iomem_resource);
+
+/* constraints to be met while allocating resources */
+struct resource_constraint {
+	resource_size_t min, max, align;
+	resource_size_t (*alignf)(void *, const struct resource *,
+			resource_size_t, resource_size_t);
+	void *alignf_data;
+};
+
+static DEFINE_RWLOCK(resource_lock);
+
+static struct resource *next_resource(struct resource *p)
+{
+	if (p->child)
+		return p->child;
+	while (!p->sibling && p->parent)
+		p = p->parent;
+	return p->sibling;
+}
+
+static struct resource *next_resource_skip_children(struct resource *p)
+{
+	while (!p->sibling && p->parent)
+		p = p->parent;
+	return p->sibling;
+}
+
+#define for_each_resource(_root, _p, _skip_children) \
+	for ((_p) = (_root)->child; (_p); \
+	     (_p) = (_skip_children) ? next_resource_skip_children(_p) : \
+				       next_resource(_p))
+
+static void *r_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct resource *p = v;
+	(*pos)++;
+	return (void *)next_resource(p);
+}
+
+#ifdef CONFIG_PROC_FS
+
+enum { MAX_IORES_LEVEL = 5 };
+
+static void *r_start(struct seq_file *m, loff_t *pos)
+	__acquires(resource_lock)
+{
+	struct resource *p = pde_data(file_inode(m->file));
+	loff_t l = 0;
+	read_lock(&resource_lock);
+	for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
+		;
+	return p;
+}
+
+static void r_stop(struct seq_file *m, void *v)
+	__releases(resource_lock)
+{
+	read_unlock(&resource_lock);
+}
+
+static int r_show(struct seq_file *m, void *v)
+{
+	struct resource *root = pde_data(file_inode(m->file));
+	struct resource *r = v, *p;
+	unsigned long long start, end;
+	int width = root->end < 0x10000 ? 4 : 8;
+	int depth;
+
+	for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
+		if (p->parent == root)
+			break;
+
+	if (file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) {
+		start = r->start;
+		end = r->end;
+	} else {
+		start = end = 0;
+	}
+
+	seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
+			depth * 2, "",
+			width, start,
+			width, end,
+			r->name ? r->name : "<BAD>");
+	return 0;
+}
+
+static const struct seq_operations resource_op = {
+	.start	= r_start,
+	.next	= r_next,
+	.stop	= r_stop,
+	.show	= r_show,
+};
+
+static int __init ioresources_init(void)
+{
+	proc_create_seq_data("ioports", 0, NULL, &resource_op,
+			&ioport_resource);
+	proc_create_seq_data("iomem", 0, NULL, &resource_op, &iomem_resource);
+	return 0;
+}
+__initcall(ioresources_init);
+
+#endif /* CONFIG_PROC_FS */
+
+static void free_resource(struct resource *res)
+{
+	/**
+	 * If the resource was allocated using memblock early during boot
+	 * we'll leak it here: we can only return full pages back to the
+	 * buddy and trying to be smart and reusing them eventually in
+	 * alloc_resource() overcomplicates resource handling.
+	 */
+	if (res && PageSlab(virt_to_head_page(res)))
+		kfree(res);
+}
+
+static struct resource *alloc_resource(gfp_t flags)
+{
+	return kzalloc(sizeof(struct resource), flags);
+}
+
+/* Return the conflict entry if you can't request it */
+static struct resource * __request_resource(struct resource *root, struct resource *new)
+{
+	resource_size_t start = new->start;
+	resource_size_t end = new->end;
+	struct resource *tmp, **p;
+
+	if (end < start)
+		return root;
+	if (start < root->start)
+		return root;
+	if (end > root->end)
+		return root;
+	p = &root->child;
+	for (;;) {
+		tmp = *p;
+		if (!tmp || tmp->start > end) {
+			new->sibling = tmp;
+			*p = new;
+			new->parent = root;
+			return NULL;
+		}
+		p = &tmp->sibling;
+		if (tmp->end < start)
+			continue;
+		return tmp;
+	}
+}
+
+static int __release_resource(struct resource *old, bool release_child)
+{
+	struct resource *tmp, **p, *chd;
+
+	p = &old->parent->child;
+	for (;;) {
+		tmp = *p;
+		if (!tmp)
+			break;
+		if (tmp == old) {
+			if (release_child || !(tmp->child)) {
+				*p = tmp->sibling;
+			} else {
+				for (chd = tmp->child;; chd = chd->sibling) {
+					chd->parent = tmp->parent;
+					if (!(chd->sibling))
+						break;
+				}
+				*p = tmp->child;
+				chd->sibling = tmp->sibling;
+			}
+			old->parent = NULL;
+			return 0;
+		}
+		p = &tmp->sibling;
+	}
+	return -EINVAL;
+}
+
+static void __release_child_resources(struct resource *r)
+{
+	struct resource *tmp, *p;
+	resource_size_t size;
+
+	p = r->child;
+	r->child = NULL;
+	while (p) {
+		tmp = p;
+		p = p->sibling;
+
+		tmp->parent = NULL;
+		tmp->sibling = NULL;
+		__release_child_resources(tmp);
+
+		printk(KERN_DEBUG "release child resource %pR\n", tmp);
+		/* need to restore size, and keep flags */
+		size = resource_size(tmp);
+		tmp->start = 0;
+		tmp->end = size - 1;
+	}
+}
+
+void release_child_resources(struct resource *r)
+{
+	write_lock(&resource_lock);
+	__release_child_resources(r);
+	write_unlock(&resource_lock);
+}
+
+/**
+ * request_resource_conflict - request and reserve an I/O or memory resource
+ * @root: root resource descriptor
+ * @new: resource descriptor desired by caller
+ *
+ * Returns 0 for success, conflict resource on error.
+ */
+struct resource *request_resource_conflict(struct resource *root, struct resource *new)
+{
+	struct resource *conflict;
+
+	write_lock(&resource_lock);
+	conflict = __request_resource(root, new);
+	write_unlock(&resource_lock);
+	return conflict;
+}
+
+/**
+ * request_resource - request and reserve an I/O or memory resource
+ * @root: root resource descriptor
+ * @new: resource descriptor desired by caller
+ *
+ * Returns 0 for success, negative error code on error.
+ */
+int request_resource(struct resource *root, struct resource *new)
+{
+	struct resource *conflict;
+
+	conflict = request_resource_conflict(root, new);
+	return conflict ? -EBUSY : 0;
+}
+
+EXPORT_SYMBOL(request_resource);
+
+/**
+ * release_resource - release a previously reserved resource
+ * @old: resource pointer
+ */
+int release_resource(struct resource *old)
+{
+	int retval;
+
+	write_lock(&resource_lock);
+	retval = __release_resource(old, true);
+	write_unlock(&resource_lock);
+	return retval;
+}
+
+EXPORT_SYMBOL(release_resource);
+
+/**
+ * find_next_iomem_res - Finds the lowest iomem resource that covers part of
+ *			 [@start..@end].
+ *
+ * If a resource is found, returns 0 and @*res is overwritten with the part
+ * of the resource that's within [@start..@end]; if none is found, returns
+ * -ENODEV.  Returns -EINVAL for invalid parameters.
+ *
+ * @start:	start address of the resource searched for
+ * @end:	end address of same resource
+ * @flags:	flags which the resource must have
+ * @desc:	descriptor the resource must have
+ * @res:	return ptr, if resource found
+ *
+ * The caller must specify @start, @end, @flags, and @desc
+ * (which may be IORES_DESC_NONE).
+ */
+static int find_next_iomem_res(resource_size_t start, resource_size_t end,
+			       unsigned long flags, unsigned long desc,
+			       struct resource *res)
+{
+	struct resource *p;
+
+	if (!res)
+		return -EINVAL;
+
+	if (start >= end)
+		return -EINVAL;
+
+	read_lock(&resource_lock);
+
+	for (p = iomem_resource.child; p; p = next_resource(p)) {
+		/* If we passed the resource we are looking for, stop */
+		if (p->start > end) {
+			p = NULL;
+			break;
+		}
+
+		/* Skip until we find a range that matches what we look for */
+		if (p->end < start)
+			continue;
+
+		if ((p->flags & flags) != flags)
+			continue;
+		if ((desc != IORES_DESC_NONE) && (desc != p->desc))
+			continue;
+
+		/* Found a match, break */
+		break;
+	}
+
+	if (p) {
+		/* copy data */
+		*res = (struct resource) {
+			.start = max(start, p->start),
+			.end = min(end, p->end),
+			.flags = p->flags,
+			.desc = p->desc,
+			.parent = p->parent,
+		};
+	}
+
+	read_unlock(&resource_lock);
+	return p ? 0 : -ENODEV;
+}
+
+static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end,
+				 unsigned long flags, unsigned long desc,
+				 void *arg,
+				 int (*func)(struct resource *, void *))
+{
+	struct resource res;
+	int ret = -EINVAL;
+
+	while (start < end &&
+	       !find_next_iomem_res(start, end, flags, desc, &res)) {
+		ret = (*func)(&res, arg);
+		if (ret)
+			break;
+
+		start = res.end + 1;
+	}
+
+	return ret;
+}
+
+/**
+ * walk_iomem_res_desc - Walks through iomem resources and calls func()
+ *			 with matching resource ranges.
+ * *
+ * @desc: I/O resource descriptor. Use IORES_DESC_NONE to skip @desc check.
+ * @flags: I/O resource flags
+ * @start: start addr
+ * @end: end addr
+ * @arg: function argument for the callback @func
+ * @func: callback function that is called for each qualifying resource area
+ *
+ * All the memory ranges which overlap start,end and also match flags and
+ * desc are valid candidates.
+ *
+ * NOTE: For a new descriptor search, define a new IORES_DESC in
+ * <linux/ioport.h> and set it in 'desc' of a target resource entry.
+ */
+int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start,
+		u64 end, void *arg, int (*func)(struct resource *, void *))
+{
+	return __walk_iomem_res_desc(start, end, flags, desc, arg, func);
+}
+EXPORT_SYMBOL_GPL(walk_iomem_res_desc);
+
+/*
+ * This function calls the @func callback against all memory ranges of type
+ * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
+ * Now, this function is only for System RAM, it deals with full ranges and
+ * not PFNs. If resources are not PFN-aligned, dealing with PFNs can truncate
+ * ranges.
+ */
+int walk_system_ram_res(u64 start, u64 end, void *arg,
+			int (*func)(struct resource *, void *))
+{
+	unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+
+	return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, arg,
+				     func);
+}
+
+/*
+ * This function calls the @func callback against all memory ranges, which
+ * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
+ */
+int walk_mem_res(u64 start, u64 end, void *arg,
+		 int (*func)(struct resource *, void *))
+{
+	unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+
+	return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, arg,
+				     func);
+}
+
+/*
+ * This function calls the @func callback against all memory ranges of type
+ * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
+ * It is to be used only for System RAM.
+ */
+int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
+			  void *arg, int (*func)(unsigned long, unsigned long, void *))
+{
+	resource_size_t start, end;
+	unsigned long flags;
+	struct resource res;
+	unsigned long pfn, end_pfn;
+	int ret = -EINVAL;
+
+	start = (u64) start_pfn << PAGE_SHIFT;
+	end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
+	flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+	while (start < end &&
+	       !find_next_iomem_res(start, end, flags, IORES_DESC_NONE, &res)) {
+		pfn = PFN_UP(res.start);
+		end_pfn = PFN_DOWN(res.end + 1);
+		if (end_pfn > pfn)
+			ret = (*func)(pfn, end_pfn - pfn, arg);
+		if (ret)
+			break;
+		start = res.end + 1;
+	}
+	return ret;
+}
+
+static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
+{
+	return 1;
+}
+
+/*
+ * This generic page_is_ram() returns true if specified address is
+ * registered as System RAM in iomem_resource list.
+ */
+int __weak page_is_ram(unsigned long pfn)
+{
+	return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
+}
+EXPORT_SYMBOL_GPL(page_is_ram);
+
+static int __region_intersects(struct resource *parent, resource_size_t start,
+			       size_t size, unsigned long flags,
+			       unsigned long desc)
+{
+	struct resource res;
+	int type = 0; int other = 0;
+	struct resource *p;
+
+	res.start = start;
+	res.end = start + size - 1;
+
+	for (p = parent->child; p ; p = p->sibling) {
+		bool is_type = (((p->flags & flags) == flags) &&
+				((desc == IORES_DESC_NONE) ||
+				 (desc == p->desc)));
+
+		if (resource_overlaps(p, &res))
+			is_type ? type++ : other++;
+	}
+
+	if (type == 0)
+		return REGION_DISJOINT;
+
+	if (other == 0)
+		return REGION_INTERSECTS;
+
+	return REGION_MIXED;
+}
+
+/**
+ * region_intersects() - determine intersection of region with known resources
+ * @start: region start address
+ * @size: size of region
+ * @flags: flags of resource (in iomem_resource)
+ * @desc: descriptor of resource (in iomem_resource) or IORES_DESC_NONE
+ *
+ * Check if the specified region partially overlaps or fully eclipses a
+ * resource identified by @flags and @desc (optional with IORES_DESC_NONE).
+ * Return REGION_DISJOINT if the region does not overlap @flags/@desc,
+ * return REGION_MIXED if the region overlaps @flags/@desc and another
+ * resource, and return REGION_INTERSECTS if the region overlaps @flags/@desc
+ * and no other defined resource. Note that REGION_INTERSECTS is also
+ * returned in the case when the specified region overlaps RAM and undefined
+ * memory holes.
+ *
+ * region_intersect() is used by memory remapping functions to ensure
+ * the user is not remapping RAM and is a vast speed up over walking
+ * through the resource table page by page.
+ */
+int region_intersects(resource_size_t start, size_t size, unsigned long flags,
+		      unsigned long desc)
+{
+	int ret;
+
+	read_lock(&resource_lock);
+	ret = __region_intersects(&iomem_resource, start, size, flags, desc);
+	read_unlock(&resource_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(region_intersects);
+
+void __weak arch_remove_reservations(struct resource *avail)
+{
+}
+
+static resource_size_t simple_align_resource(void *data,
+					     const struct resource *avail,
+					     resource_size_t size,
+					     resource_size_t align)
+{
+	return avail->start;
+}
+
+static void resource_clip(struct resource *res, resource_size_t min,
+			  resource_size_t max)
+{
+	if (res->start < min)
+		res->start = min;
+	if (res->end > max)
+		res->end = max;
+}
+
+/*
+ * Find empty slot in the resource tree with the given range and
+ * alignment constraints
+ */
+static int __find_resource(struct resource *root, struct resource *old,
+			 struct resource *new,
+			 resource_size_t  size,
+			 struct resource_constraint *constraint)
+{
+	struct resource *this = root->child;
+	struct resource tmp = *new, avail, alloc;
+
+	tmp.start = root->start;
+	/*
+	 * Skip past an allocated resource that starts at 0, since the assignment
+	 * of this->start - 1 to tmp->end below would cause an underflow.
+	 */
+	if (this && this->start == root->start) {
+		tmp.start = (this == old) ? old->start : this->end + 1;
+		this = this->sibling;
+	}
+	for(;;) {
+		if (this)
+			tmp.end = (this == old) ?  this->end : this->start - 1;
+		else
+			tmp.end = root->end;
+
+		if (tmp.end < tmp.start)
+			goto next;
+
+		resource_clip(&tmp, constraint->min, constraint->max);
+		arch_remove_reservations(&tmp);
+
+		/* Check for overflow after ALIGN() */
+		avail.start = ALIGN(tmp.start, constraint->align);
+		avail.end = tmp.end;
+		avail.flags = new->flags & ~IORESOURCE_UNSET;
+		if (avail.start >= tmp.start) {
+			alloc.flags = avail.flags;
+			alloc.start = constraint->alignf(constraint->alignf_data, &avail,
+					size, constraint->align);
+			alloc.end = alloc.start + size - 1;
+			if (alloc.start <= alloc.end &&
+			    resource_contains(&avail, &alloc)) {
+				new->start = alloc.start;
+				new->end = alloc.end;
+				return 0;
+			}
+		}
+
+next:		if (!this || this->end == root->end)
+			break;
+
+		if (this != old)
+			tmp.start = this->end + 1;
+		this = this->sibling;
+	}
+	return -EBUSY;
+}
+
+/*
+ * Find empty slot in the resource tree given range and alignment.
+ */
+static int find_resource(struct resource *root, struct resource *new,
+			resource_size_t size,
+			struct resource_constraint  *constraint)
+{
+	return  __find_resource(root, NULL, new, size, constraint);
+}
+
+/**
+ * reallocate_resource - allocate a slot in the resource tree given range & alignment.
+ *	The resource will be relocated if the new size cannot be reallocated in the
+ *	current location.
+ *
+ * @root: root resource descriptor
+ * @old:  resource descriptor desired by caller
+ * @newsize: new size of the resource descriptor
+ * @constraint: the size and alignment constraints to be met.
+ */
+static int reallocate_resource(struct resource *root, struct resource *old,
+			       resource_size_t newsize,
+			       struct resource_constraint *constraint)
+{
+	int err=0;
+	struct resource new = *old;
+	struct resource *conflict;
+
+	write_lock(&resource_lock);
+
+	if ((err = __find_resource(root, old, &new, newsize, constraint)))
+		goto out;
+
+	if (resource_contains(&new, old)) {
+		old->start = new.start;
+		old->end = new.end;
+		goto out;
+	}
+
+	if (old->child) {
+		err = -EBUSY;
+		goto out;
+	}
+
+	if (resource_contains(old, &new)) {
+		old->start = new.start;
+		old->end = new.end;
+	} else {
+		__release_resource(old, true);
+		*old = new;
+		conflict = __request_resource(root, old);
+		BUG_ON(conflict);
+	}
+out:
+	write_unlock(&resource_lock);
+	return err;
+}
+
+
+/**
+ * allocate_resource - allocate empty slot in the resource tree given range & alignment.
+ * 	The resource will be reallocated with a new size if it was already allocated
+ * @root: root resource descriptor
+ * @new: resource descriptor desired by caller
+ * @size: requested resource region size
+ * @min: minimum boundary to allocate
+ * @max: maximum boundary to allocate
+ * @align: alignment requested, in bytes
+ * @alignf: alignment function, optional, called if not NULL
+ * @alignf_data: arbitrary data to pass to the @alignf function
+ */
+int allocate_resource(struct resource *root, struct resource *new,
+		      resource_size_t size, resource_size_t min,
+		      resource_size_t max, resource_size_t align,
+		      resource_size_t (*alignf)(void *,
+						const struct resource *,
+						resource_size_t,
+						resource_size_t),
+		      void *alignf_data)
+{
+	int err;
+	struct resource_constraint constraint;
+
+	if (!alignf)
+		alignf = simple_align_resource;
+
+	constraint.min = min;
+	constraint.max = max;
+	constraint.align = align;
+	constraint.alignf = alignf;
+	constraint.alignf_data = alignf_data;
+
+	if ( new->parent ) {
+		/* resource is already allocated, try reallocating with
+		   the new constraints */
+		return reallocate_resource(root, new, size, &constraint);
+	}
+
+	write_lock(&resource_lock);
+	err = find_resource(root, new, size, &constraint);
+	if (err >= 0 && __request_resource(root, new))
+		err = -EBUSY;
+	write_unlock(&resource_lock);
+	return err;
+}
+
+EXPORT_SYMBOL(allocate_resource);
+
+/**
+ * lookup_resource - find an existing resource by a resource start address
+ * @root: root resource descriptor
+ * @start: resource start address
+ *
+ * Returns a pointer to the resource if found, NULL otherwise
+ */
+struct resource *lookup_resource(struct resource *root, resource_size_t start)
+{
+	struct resource *res;
+
+	read_lock(&resource_lock);
+	for (res = root->child; res; res = res->sibling) {
+		if (res->start == start)
+			break;
+	}
+	read_unlock(&resource_lock);
+
+	return res;
+}
+
+/*
+ * Insert a resource into the resource tree. If successful, return NULL,
+ * otherwise return the conflicting resource (compare to __request_resource())
+ */
+static struct resource * __insert_resource(struct resource *parent, struct resource *new)
+{
+	struct resource *first, *next;
+
+	for (;; parent = first) {
+		first = __request_resource(parent, new);
+		if (!first)
+			return first;
+
+		if (first == parent)
+			return first;
+		if (WARN_ON(first == new))	/* duplicated insertion */
+			return first;
+
+		if ((first->start > new->start) || (first->end < new->end))
+			break;
+		if ((first->start == new->start) && (first->end == new->end))
+			break;
+	}
+
+	for (next = first; ; next = next->sibling) {
+		/* Partial overlap? Bad, and unfixable */
+		if (next->start < new->start || next->end > new->end)
+			return next;
+		if (!next->sibling)
+			break;
+		if (next->sibling->start > new->end)
+			break;
+	}
+
+	new->parent = parent;
+	new->sibling = next->sibling;
+	new->child = first;
+
+	next->sibling = NULL;
+	for (next = first; next; next = next->sibling)
+		next->parent = new;
+
+	if (parent->child == first) {
+		parent->child = new;
+	} else {
+		next = parent->child;
+		while (next->sibling != first)
+			next = next->sibling;
+		next->sibling = new;
+	}
+	return NULL;
+}
+
+/**
+ * insert_resource_conflict - Inserts resource in the resource tree
+ * @parent: parent of the new resource
+ * @new: new resource to insert
+ *
+ * Returns 0 on success, conflict resource if the resource can't be inserted.
+ *
+ * This function is equivalent to request_resource_conflict when no conflict
+ * happens. If a conflict happens, and the conflicting resources
+ * entirely fit within the range of the new resource, then the new
+ * resource is inserted and the conflicting resources become children of
+ * the new resource.
+ *
+ * This function is intended for producers of resources, such as FW modules
+ * and bus drivers.
+ */
+struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
+{
+	struct resource *conflict;
+
+	write_lock(&resource_lock);
+	conflict = __insert_resource(parent, new);
+	write_unlock(&resource_lock);
+	return conflict;
+}
+
+/**
+ * insert_resource - Inserts a resource in the resource tree
+ * @parent: parent of the new resource
+ * @new: new resource to insert
+ *
+ * Returns 0 on success, -EBUSY if the resource can't be inserted.
+ *
+ * This function is intended for producers of resources, such as FW modules
+ * and bus drivers.
+ */
+int insert_resource(struct resource *parent, struct resource *new)
+{
+	struct resource *conflict;
+
+	conflict = insert_resource_conflict(parent, new);
+	return conflict ? -EBUSY : 0;
+}
+EXPORT_SYMBOL_GPL(insert_resource);
+
+/**
+ * insert_resource_expand_to_fit - Insert a resource into the resource tree
+ * @root: root resource descriptor
+ * @new: new resource to insert
+ *
+ * Insert a resource into the resource tree, possibly expanding it in order
+ * to make it encompass any conflicting resources.
+ */
+void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
+{
+	if (new->parent)
+		return;
+
+	write_lock(&resource_lock);
+	for (;;) {
+		struct resource *conflict;
+
+		conflict = __insert_resource(root, new);
+		if (!conflict)
+			break;
+		if (conflict == root)
+			break;
+
+		/* Ok, expand resource to cover the conflict, then try again .. */
+		if (conflict->start < new->start)
+			new->start = conflict->start;
+		if (conflict->end > new->end)
+			new->end = conflict->end;
+
+		printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
+	}
+	write_unlock(&resource_lock);
+}
+/*
+ * Not for general consumption, only early boot memory map parsing, PCI
+ * resource discovery, and late discovery of CXL resources are expected
+ * to use this interface. The former are built-in and only the latter,
+ * CXL, is a module.
+ */
+EXPORT_SYMBOL_NS_GPL(insert_resource_expand_to_fit, CXL);
+
+/**
+ * remove_resource - Remove a resource in the resource tree
+ * @old: resource to remove
+ *
+ * Returns 0 on success, -EINVAL if the resource is not valid.
+ *
+ * This function removes a resource previously inserted by insert_resource()
+ * or insert_resource_conflict(), and moves the children (if any) up to
+ * where they were before.  insert_resource() and insert_resource_conflict()
+ * insert a new resource, and move any conflicting resources down to the
+ * children of the new resource.
+ *
+ * insert_resource(), insert_resource_conflict() and remove_resource() are
+ * intended for producers of resources, such as FW modules and bus drivers.
+ */
+int remove_resource(struct resource *old)
+{
+	int retval;
+
+	write_lock(&resource_lock);
+	retval = __release_resource(old, false);
+	write_unlock(&resource_lock);
+	return retval;
+}
+EXPORT_SYMBOL_GPL(remove_resource);
+
+static int __adjust_resource(struct resource *res, resource_size_t start,
+				resource_size_t size)
+{
+	struct resource *tmp, *parent = res->parent;
+	resource_size_t end = start + size - 1;
+	int result = -EBUSY;
+
+	if (!parent)
+		goto skip;
+
+	if ((start < parent->start) || (end > parent->end))
+		goto out;
+
+	if (res->sibling && (res->sibling->start <= end))
+		goto out;
+
+	tmp = parent->child;
+	if (tmp != res) {
+		while (tmp->sibling != res)
+			tmp = tmp->sibling;
+		if (start <= tmp->end)
+			goto out;
+	}
+
+skip:
+	for (tmp = res->child; tmp; tmp = tmp->sibling)
+		if ((tmp->start < start) || (tmp->end > end))
+			goto out;
+
+	res->start = start;
+	res->end = end;
+	result = 0;
+
+ out:
+	return result;
+}
+
+/**
+ * adjust_resource - modify a resource's start and size
+ * @res: resource to modify
+ * @start: new start value
+ * @size: new size
+ *
+ * Given an existing resource, change its start and size to match the
+ * arguments.  Returns 0 on success, -EBUSY if it can't fit.
+ * Existing children of the resource are assumed to be immutable.
+ */
+int adjust_resource(struct resource *res, resource_size_t start,
+		    resource_size_t size)
+{
+	int result;
+
+	write_lock(&resource_lock);
+	result = __adjust_resource(res, start, size);
+	write_unlock(&resource_lock);
+	return result;
+}
+EXPORT_SYMBOL(adjust_resource);
+
+static void __init
+__reserve_region_with_split(struct resource *root, resource_size_t start,
+			    resource_size_t end, const char *name)
+{
+	struct resource *parent = root;
+	struct resource *conflict;
+	struct resource *res = alloc_resource(GFP_ATOMIC);
+	struct resource *next_res = NULL;
+	int type = resource_type(root);
+
+	if (!res)
+		return;
+
+	res->name = name;
+	res->start = start;
+	res->end = end;
+	res->flags = type | IORESOURCE_BUSY;
+	res->desc = IORES_DESC_NONE;
+
+	while (1) {
+
+		conflict = __request_resource(parent, res);
+		if (!conflict) {
+			if (!next_res)
+				break;
+			res = next_res;
+			next_res = NULL;
+			continue;
+		}
+
+		/* conflict covered whole area */
+		if (conflict->start <= res->start &&
+				conflict->end >= res->end) {
+			free_resource(res);
+			WARN_ON(next_res);
+			break;
+		}
+
+		/* failed, split and try again */
+		if (conflict->start > res->start) {
+			end = res->end;
+			res->end = conflict->start - 1;
+			if (conflict->end < end) {
+				next_res = alloc_resource(GFP_ATOMIC);
+				if (!next_res) {
+					free_resource(res);
+					break;
+				}
+				next_res->name = name;
+				next_res->start = conflict->end + 1;
+				next_res->end = end;
+				next_res->flags = type | IORESOURCE_BUSY;
+				next_res->desc = IORES_DESC_NONE;
+			}
+		} else {
+			res->start = conflict->end + 1;
+		}
+	}
+
+}
+
+void __init
+reserve_region_with_split(struct resource *root, resource_size_t start,
+			  resource_size_t end, const char *name)
+{
+	int abort = 0;
+
+	write_lock(&resource_lock);
+	if (root->start > start || root->end < end) {
+		pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
+		       (unsigned long long)start, (unsigned long long)end,
+		       root);
+		if (start > root->end || end < root->start)
+			abort = 1;
+		else {
+			if (end > root->end)
+				end = root->end;
+			if (start < root->start)
+				start = root->start;
+			pr_err("fixing request to [0x%llx-0x%llx]\n",
+			       (unsigned long long)start,
+			       (unsigned long long)end);
+		}
+		dump_stack();
+	}
+	if (!abort)
+		__reserve_region_with_split(root, start, end, name);
+	write_unlock(&resource_lock);
+}
+
+/**
+ * resource_alignment - calculate resource's alignment
+ * @res: resource pointer
+ *
+ * Returns alignment on success, 0 (invalid alignment) on failure.
+ */
+resource_size_t resource_alignment(struct resource *res)
+{
+	switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
+	case IORESOURCE_SIZEALIGN:
+		return resource_size(res);
+	case IORESOURCE_STARTALIGN:
+		return res->start;
+	default:
+		return 0;
+	}
+}
+
+/*
+ * This is compatibility stuff for IO resources.
+ *
+ * Note how this, unlike the above, knows about
+ * the IO flag meanings (busy etc).
+ *
+ * request_region creates a new busy region.
+ *
+ * release_region releases a matching busy region.
+ */
+
+static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
+
+static struct inode *iomem_inode;
+
+#ifdef CONFIG_IO_STRICT_DEVMEM
+static void revoke_iomem(struct resource *res)
+{
+	/* pairs with smp_store_release() in iomem_init_inode() */
+	struct inode *inode = smp_load_acquire(&iomem_inode);
+
+	/*
+	 * Check that the initialization has completed. Losing the race
+	 * is ok because it means drivers are claiming resources before
+	 * the fs_initcall level of init and prevent iomem_get_mapping users
+	 * from establishing mappings.
+	 */
+	if (!inode)
+		return;
+
+	/*
+	 * The expectation is that the driver has successfully marked
+	 * the resource busy by this point, so devmem_is_allowed()
+	 * should start returning false, however for performance this
+	 * does not iterate the entire resource range.
+	 */
+	if (devmem_is_allowed(PHYS_PFN(res->start)) &&
+	    devmem_is_allowed(PHYS_PFN(res->end))) {
+		/*
+		 * *cringe* iomem=relaxed says "go ahead, what's the
+		 * worst that can happen?"
+		 */
+		return;
+	}
+
+	unmap_mapping_range(inode->i_mapping, res->start, resource_size(res), 1);
+}
+#else
+static void revoke_iomem(struct resource *res) {}
+#endif
+
+struct address_space *iomem_get_mapping(void)
+{
+	/*
+	 * This function is only called from file open paths, hence guaranteed
+	 * that fs_initcalls have completed and no need to check for NULL. But
+	 * since revoke_iomem can be called before the initcall we still need
+	 * the barrier to appease checkers.
+	 */
+	return smp_load_acquire(&iomem_inode)->i_mapping;
+}
+
+static int __request_region_locked(struct resource *res, struct resource *parent,
+				   resource_size_t start, resource_size_t n,
+				   const char *name, int flags)
+{
+	DECLARE_WAITQUEUE(wait, current);
+
+	res->name = name;
+	res->start = start;
+	res->end = start + n - 1;
+
+	for (;;) {
+		struct resource *conflict;
+
+		res->flags = resource_type(parent) | resource_ext_type(parent);
+		res->flags |= IORESOURCE_BUSY | flags;
+		res->desc = parent->desc;
+
+		conflict = __request_resource(parent, res);
+		if (!conflict)
+			break;
+		/*
+		 * mm/hmm.c reserves physical addresses which then
+		 * become unavailable to other users.  Conflicts are
+		 * not expected.  Warn to aid debugging if encountered.
+		 */
+		if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
+			pr_warn("Unaddressable device %s %pR conflicts with %pR",
+				conflict->name, conflict, res);
+		}
+		if (conflict != parent) {
+			if (!(conflict->flags & IORESOURCE_BUSY)) {
+				parent = conflict;
+				continue;
+			}
+		}
+		if (conflict->flags & flags & IORESOURCE_MUXED) {
+			add_wait_queue(&muxed_resource_wait, &wait);
+			write_unlock(&resource_lock);
+			set_current_state(TASK_UNINTERRUPTIBLE);
+			schedule();
+			remove_wait_queue(&muxed_resource_wait, &wait);
+			write_lock(&resource_lock);
+			continue;
+		}
+		/* Uhhuh, that didn't work out.. */
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+/**
+ * __request_region - create a new busy resource region
+ * @parent: parent resource descriptor
+ * @start: resource start address
+ * @n: resource region size
+ * @name: reserving caller's ID string
+ * @flags: IO resource flags
+ */
+struct resource *__request_region(struct resource *parent,
+				  resource_size_t start, resource_size_t n,
+				  const char *name, int flags)
+{
+	struct resource *res = alloc_resource(GFP_KERNEL);
+	int ret;
+
+	if (!res)
+		return NULL;
+
+	write_lock(&resource_lock);
+	ret = __request_region_locked(res, parent, start, n, name, flags);
+	write_unlock(&resource_lock);
+
+	if (ret) {
+		free_resource(res);
+		return NULL;
+	}
+
+	if (parent == &iomem_resource)
+		revoke_iomem(res);
+
+	return res;
+}
+EXPORT_SYMBOL(__request_region);
+
+/**
+ * __release_region - release a previously reserved resource region
+ * @parent: parent resource descriptor
+ * @start: resource start address
+ * @n: resource region size
+ *
+ * The described resource region must match a currently busy region.
+ */
+void __release_region(struct resource *parent, resource_size_t start,
+		      resource_size_t n)
+{
+	struct resource **p;
+	resource_size_t end;
+
+	p = &parent->child;
+	end = start + n - 1;
+
+	write_lock(&resource_lock);
+
+	for (;;) {
+		struct resource *res = *p;
+
+		if (!res)
+			break;
+		if (res->start <= start && res->end >= end) {
+			if (!(res->flags & IORESOURCE_BUSY)) {
+				p = &res->child;
+				continue;
+			}
+			if (res->start != start || res->end != end)
+				break;
+			*p = res->sibling;
+			write_unlock(&resource_lock);
+			if (res->flags & IORESOURCE_MUXED)
+				wake_up(&muxed_resource_wait);
+			free_resource(res);
+			return;
+		}
+		p = &res->sibling;
+	}
+
+	write_unlock(&resource_lock);
+
+	printk(KERN_WARNING "Trying to free nonexistent resource "
+		"<%016llx-%016llx>\n", (unsigned long long)start,
+		(unsigned long long)end);
+}
+EXPORT_SYMBOL(__release_region);
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+/**
+ * release_mem_region_adjustable - release a previously reserved memory region
+ * @start: resource start address
+ * @size: resource region size
+ *
+ * This interface is intended for memory hot-delete.  The requested region
+ * is released from a currently busy memory resource.  The requested region
+ * must either match exactly or fit into a single busy resource entry.  In
+ * the latter case, the remaining resource is adjusted accordingly.
+ * Existing children of the busy memory resource must be immutable in the
+ * request.
+ *
+ * Note:
+ * - Additional release conditions, such as overlapping region, can be
+ *   supported after they are confirmed as valid cases.
+ * - When a busy memory resource gets split into two entries, the code
+ *   assumes that all children remain in the lower address entry for
+ *   simplicity.  Enhance this logic when necessary.
+ */
+void release_mem_region_adjustable(resource_size_t start, resource_size_t size)
+{
+	struct resource *parent = &iomem_resource;
+	struct resource *new_res = NULL;
+	bool alloc_nofail = false;
+	struct resource **p;
+	struct resource *res;
+	resource_size_t end;
+
+	end = start + size - 1;
+	if (WARN_ON_ONCE((start < parent->start) || (end > parent->end)))
+		return;
+
+	/*
+	 * We free up quite a lot of memory on memory hotunplug (esp., memap),
+	 * just before releasing the region. This is highly unlikely to
+	 * fail - let's play save and make it never fail as the caller cannot
+	 * perform any error handling (e.g., trying to re-add memory will fail
+	 * similarly).
+	 */
+retry:
+	new_res = alloc_resource(GFP_KERNEL | (alloc_nofail ? __GFP_NOFAIL : 0));
+
+	p = &parent->child;
+	write_lock(&resource_lock);
+
+	while ((res = *p)) {
+		if (res->start >= end)
+			break;
+
+		/* look for the next resource if it does not fit into */
+		if (res->start > start || res->end < end) {
+			p = &res->sibling;
+			continue;
+		}
+
+		if (!(res->flags & IORESOURCE_MEM))
+			break;
+
+		if (!(res->flags & IORESOURCE_BUSY)) {
+			p = &res->child;
+			continue;
+		}
+
+		/* found the target resource; let's adjust accordingly */
+		if (res->start == start && res->end == end) {
+			/* free the whole entry */
+			*p = res->sibling;
+			free_resource(res);
+		} else if (res->start == start && res->end != end) {
+			/* adjust the start */
+			WARN_ON_ONCE(__adjust_resource(res, end + 1,
+						       res->end - end));
+		} else if (res->start != start && res->end == end) {
+			/* adjust the end */
+			WARN_ON_ONCE(__adjust_resource(res, res->start,
+						       start - res->start));
+		} else {
+			/* split into two entries - we need a new resource */
+			if (!new_res) {
+				new_res = alloc_resource(GFP_ATOMIC);
+				if (!new_res) {
+					alloc_nofail = true;
+					write_unlock(&resource_lock);
+					goto retry;
+				}
+			}
+			new_res->name = res->name;
+			new_res->start = end + 1;
+			new_res->end = res->end;
+			new_res->flags = res->flags;
+			new_res->desc = res->desc;
+			new_res->parent = res->parent;
+			new_res->sibling = res->sibling;
+			new_res->child = NULL;
+
+			if (WARN_ON_ONCE(__adjust_resource(res, res->start,
+							   start - res->start)))
+				break;
+			res->sibling = new_res;
+			new_res = NULL;
+		}
+
+		break;
+	}
+
+	write_unlock(&resource_lock);
+	free_resource(new_res);
+}
+#endif	/* CONFIG_MEMORY_HOTREMOVE */
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+static bool system_ram_resources_mergeable(struct resource *r1,
+					   struct resource *r2)
+{
+	/* We assume either r1 or r2 is IORESOURCE_SYSRAM_MERGEABLE. */
+	return r1->flags == r2->flags && r1->end + 1 == r2->start &&
+	       r1->name == r2->name && r1->desc == r2->desc &&
+	       !r1->child && !r2->child;
+}
+
+/**
+ * merge_system_ram_resource - mark the System RAM resource mergeable and try to
+ *	merge it with adjacent, mergeable resources
+ * @res: resource descriptor
+ *
+ * This interface is intended for memory hotplug, whereby lots of contiguous
+ * system ram resources are added (e.g., via add_memory*()) by a driver, and
+ * the actual resource boundaries are not of interest (e.g., it might be
+ * relevant for DIMMs). Only resources that are marked mergeable, that have the
+ * same parent, and that don't have any children are considered. All mergeable
+ * resources must be immutable during the request.
+ *
+ * Note:
+ * - The caller has to make sure that no pointers to resources that are
+ *   marked mergeable are used anymore after this call - the resource might
+ *   be freed and the pointer might be stale!
+ * - release_mem_region_adjustable() will split on demand on memory hotunplug
+ */
+void merge_system_ram_resource(struct resource *res)
+{
+	const unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+	struct resource *cur;
+
+	if (WARN_ON_ONCE((res->flags & flags) != flags))
+		return;
+
+	write_lock(&resource_lock);
+	res->flags |= IORESOURCE_SYSRAM_MERGEABLE;
+
+	/* Try to merge with next item in the list. */
+	cur = res->sibling;
+	if (cur && system_ram_resources_mergeable(res, cur)) {
+		res->end = cur->end;
+		res->sibling = cur->sibling;
+		free_resource(cur);
+	}
+
+	/* Try to merge with previous item in the list. */
+	cur = res->parent->child;
+	while (cur && cur->sibling != res)
+		cur = cur->sibling;
+	if (cur && system_ram_resources_mergeable(cur, res)) {
+		cur->end = res->end;
+		cur->sibling = res->sibling;
+		free_resource(res);
+	}
+	write_unlock(&resource_lock);
+}
+#endif	/* CONFIG_MEMORY_HOTPLUG */
+
+/*
+ * Managed region resource
+ */
+static void devm_resource_release(struct device *dev, void *ptr)
+{
+	struct resource **r = ptr;
+
+	release_resource(*r);
+}
+
+/**
+ * devm_request_resource() - request and reserve an I/O or memory resource
+ * @dev: device for which to request the resource
+ * @root: root of the resource tree from which to request the resource
+ * @new: descriptor of the resource to request
+ *
+ * This is a device-managed version of request_resource(). There is usually
+ * no need to release resources requested by this function explicitly since
+ * that will be taken care of when the device is unbound from its driver.
+ * If for some reason the resource needs to be released explicitly, because
+ * of ordering issues for example, drivers must call devm_release_resource()
+ * rather than the regular release_resource().
+ *
+ * When a conflict is detected between any existing resources and the newly
+ * requested resource, an error message will be printed.
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+int devm_request_resource(struct device *dev, struct resource *root,
+			  struct resource *new)
+{
+	struct resource *conflict, **ptr;
+
+	ptr = devres_alloc(devm_resource_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	*ptr = new;
+
+	conflict = request_resource_conflict(root, new);
+	if (conflict) {
+		dev_err(dev, "resource collision: %pR conflicts with %s %pR\n",
+			new, conflict->name, conflict);
+		devres_free(ptr);
+		return -EBUSY;
+	}
+
+	devres_add(dev, ptr);
+	return 0;
+}
+EXPORT_SYMBOL(devm_request_resource);
+
+static int devm_resource_match(struct device *dev, void *res, void *data)
+{
+	struct resource **ptr = res;
+
+	return *ptr == data;
+}
+
+/**
+ * devm_release_resource() - release a previously requested resource
+ * @dev: device for which to release the resource
+ * @new: descriptor of the resource to release
+ *
+ * Releases a resource previously requested using devm_request_resource().
+ */
+void devm_release_resource(struct device *dev, struct resource *new)
+{
+	WARN_ON(devres_release(dev, devm_resource_release, devm_resource_match,
+			       new));
+}
+EXPORT_SYMBOL(devm_release_resource);
+
+struct region_devres {
+	struct resource *parent;
+	resource_size_t start;
+	resource_size_t n;
+};
+
+static void devm_region_release(struct device *dev, void *res)
+{
+	struct region_devres *this = res;
+
+	__release_region(this->parent, this->start, this->n);
+}
+
+static int devm_region_match(struct device *dev, void *res, void *match_data)
+{
+	struct region_devres *this = res, *match = match_data;
+
+	return this->parent == match->parent &&
+		this->start == match->start && this->n == match->n;
+}
+
+struct resource *
+__devm_request_region(struct device *dev, struct resource *parent,
+		      resource_size_t start, resource_size_t n, const char *name)
+{
+	struct region_devres *dr = NULL;
+	struct resource *res;
+
+	dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
+			  GFP_KERNEL);
+	if (!dr)
+		return NULL;
+
+	dr->parent = parent;
+	dr->start = start;
+	dr->n = n;
+
+	res = __request_region(parent, start, n, name, 0);
+	if (res)
+		devres_add(dev, dr);
+	else
+		devres_free(dr);
+
+	return res;
+}
+EXPORT_SYMBOL(__devm_request_region);
+
+void __devm_release_region(struct device *dev, struct resource *parent,
+			   resource_size_t start, resource_size_t n)
+{
+	struct region_devres match_data = { parent, start, n };
+
+	__release_region(parent, start, n);
+	WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
+			       &match_data));
+}
+EXPORT_SYMBOL(__devm_release_region);
+
+/*
+ * Reserve I/O ports or memory based on "reserve=" kernel parameter.
+ */
+#define MAXRESERVE 4
+static int __init reserve_setup(char *str)
+{
+	static int reserved;
+	static struct resource reserve[MAXRESERVE];
+
+	for (;;) {
+		unsigned int io_start, io_num;
+		int x = reserved;
+		struct resource *parent;
+
+		if (get_option(&str, &io_start) != 2)
+			break;
+		if (get_option(&str, &io_num) == 0)
+			break;
+		if (x < MAXRESERVE) {
+			struct resource *res = reserve + x;
+
+			/*
+			 * If the region starts below 0x10000, we assume it's
+			 * I/O port space; otherwise assume it's memory.
+			 */
+			if (io_start < 0x10000) {
+				res->flags = IORESOURCE_IO;
+				parent = &ioport_resource;
+			} else {
+				res->flags = IORESOURCE_MEM;
+				parent = &iomem_resource;
+			}
+			res->name = "reserved";
+			res->start = io_start;
+			res->end = io_start + io_num - 1;
+			res->flags |= IORESOURCE_BUSY;
+			res->desc = IORES_DESC_NONE;
+			res->child = NULL;
+			if (request_resource(parent, res) == 0)
+				reserved = x+1;
+		}
+	}
+	return 1;
+}
+__setup("reserve=", reserve_setup);
+
+/*
+ * Check if the requested addr and size spans more than any slot in the
+ * iomem resource tree.
+ */
+int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
+{
+	struct resource *p = &iomem_resource;
+	int err = 0;
+	loff_t l;
+
+	read_lock(&resource_lock);
+	for (p = p->child; p ; p = r_next(NULL, p, &l)) {
+		/*
+		 * We can probably skip the resources without
+		 * IORESOURCE_IO attribute?
+		 */
+		if (p->start >= addr + size)
+			continue;
+		if (p->end < addr)
+			continue;
+		if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
+		    PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
+			continue;
+		/*
+		 * if a resource is "BUSY", it's not a hardware resource
+		 * but a driver mapping of such a resource; we don't want
+		 * to warn for those; some drivers legitimately map only
+		 * partial hardware resources. (example: vesafb)
+		 */
+		if (p->flags & IORESOURCE_BUSY)
+			continue;
+
+		printk(KERN_WARNING "resource sanity check: requesting [mem %#010llx-%#010llx], which spans more than %s %pR\n",
+		       (unsigned long long)addr,
+		       (unsigned long long)(addr + size - 1),
+		       p->name, p);
+		err = -1;
+		break;
+	}
+	read_unlock(&resource_lock);
+
+	return err;
+}
+
+#ifdef CONFIG_STRICT_DEVMEM
+static int strict_iomem_checks = 1;
+#else
+static int strict_iomem_checks;
+#endif
+
+/*
+ * Check if an address is exclusive to the kernel and must not be mapped to
+ * user space, for example, via /dev/mem.
+ *
+ * Returns true if exclusive to the kernel, otherwise returns false.
+ */
+bool resource_is_exclusive(struct resource *root, u64 addr, resource_size_t size)
+{
+	const unsigned int exclusive_system_ram = IORESOURCE_SYSTEM_RAM |
+						  IORESOURCE_EXCLUSIVE;
+	bool skip_children = false, err = false;
+	struct resource *p;
+
+	read_lock(&resource_lock);
+	for_each_resource(root, p, skip_children) {
+		if (p->start >= addr + size)
+			break;
+		if (p->end < addr) {
+			skip_children = true;
+			continue;
+		}
+		skip_children = false;
+
+		/*
+		 * IORESOURCE_SYSTEM_RAM resources are exclusive if
+		 * IORESOURCE_EXCLUSIVE is set, even if they
+		 * are not busy and even if "iomem=relaxed" is set. The
+		 * responsible driver dynamically adds/removes system RAM within
+		 * such an area and uncontrolled access is dangerous.
+		 */
+		if ((p->flags & exclusive_system_ram) == exclusive_system_ram) {
+			err = true;
+			break;
+		}
+
+		/*
+		 * A resource is exclusive if IORESOURCE_EXCLUSIVE is set
+		 * or CONFIG_IO_STRICT_DEVMEM is enabled and the
+		 * resource is busy.
+		 */
+		if (!strict_iomem_checks || !(p->flags & IORESOURCE_BUSY))
+			continue;
+		if (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM)
+				|| p->flags & IORESOURCE_EXCLUSIVE) {
+			err = true;
+			break;
+		}
+	}
+	read_unlock(&resource_lock);
+
+	return err;
+}
+
+bool iomem_is_exclusive(u64 addr)
+{
+	return resource_is_exclusive(&iomem_resource, addr & PAGE_MASK,
+				     PAGE_SIZE);
+}
+
+struct resource_entry *resource_list_create_entry(struct resource *res,
+						  size_t extra_size)
+{
+	struct resource_entry *entry;
+
+	entry = kzalloc(sizeof(*entry) + extra_size, GFP_KERNEL);
+	if (entry) {
+		INIT_LIST_HEAD(&entry->node);
+		entry->res = res ? res : &entry->__res;
+	}
+
+	return entry;
+}
+EXPORT_SYMBOL(resource_list_create_entry);
+
+void resource_list_free(struct list_head *head)
+{
+	struct resource_entry *entry, *tmp;
+
+	list_for_each_entry_safe(entry, tmp, head, node)
+		resource_list_destroy_entry(entry);
+}
+EXPORT_SYMBOL(resource_list_free);
+
+#ifdef CONFIG_GET_FREE_REGION
+#define GFR_DESCENDING		(1UL << 0)
+#define GFR_REQUEST_REGION	(1UL << 1)
+#define GFR_DEFAULT_ALIGN (1UL << PA_SECTION_SHIFT)
+
+static resource_size_t gfr_start(struct resource *base, resource_size_t size,
+				 resource_size_t align, unsigned long flags)
+{
+	if (flags & GFR_DESCENDING) {
+		resource_size_t end;
+
+		end = min_t(resource_size_t, base->end,
+			    (1ULL << MAX_PHYSMEM_BITS) - 1);
+		return end - size + 1;
+	}
+
+	return ALIGN(base->start, align);
+}
+
+static bool gfr_continue(struct resource *base, resource_size_t addr,
+			 resource_size_t size, unsigned long flags)
+{
+	if (flags & GFR_DESCENDING)
+		return addr > size && addr >= base->start;
+	/*
+	 * In the ascend case be careful that the last increment by
+	 * @size did not wrap 0.
+	 */
+	return addr > addr - size &&
+	       addr <= min_t(resource_size_t, base->end,
+			     (1ULL << MAX_PHYSMEM_BITS) - 1);
+}
+
+static resource_size_t gfr_next(resource_size_t addr, resource_size_t size,
+				unsigned long flags)
+{
+	if (flags & GFR_DESCENDING)
+		return addr - size;
+	return addr + size;
+}
+
+static void remove_free_mem_region(void *_res)
+{
+	struct resource *res = _res;
+
+	if (res->parent)
+		remove_resource(res);
+	free_resource(res);
+}
+
+static struct resource *
+get_free_mem_region(struct device *dev, struct resource *base,
+		    resource_size_t size, const unsigned long align,
+		    const char *name, const unsigned long desc,
+		    const unsigned long flags)
+{
+	resource_size_t addr;
+	struct resource *res;
+	struct region_devres *dr = NULL;
+
+	size = ALIGN(size, align);
+
+	res = alloc_resource(GFP_KERNEL);
+	if (!res)
+		return ERR_PTR(-ENOMEM);
+
+	if (dev && (flags & GFR_REQUEST_REGION)) {
+		dr = devres_alloc(devm_region_release,
+				sizeof(struct region_devres), GFP_KERNEL);
+		if (!dr) {
+			free_resource(res);
+			return ERR_PTR(-ENOMEM);
+		}
+	} else if (dev) {
+		if (devm_add_action_or_reset(dev, remove_free_mem_region, res))
+			return ERR_PTR(-ENOMEM);
+	}
+
+	write_lock(&resource_lock);
+	for (addr = gfr_start(base, size, align, flags);
+	     gfr_continue(base, addr, size, flags);
+	     addr = gfr_next(addr, size, flags)) {
+		if (__region_intersects(base, addr, size, 0, IORES_DESC_NONE) !=
+		    REGION_DISJOINT)
+			continue;
+
+		if (flags & GFR_REQUEST_REGION) {
+			if (__request_region_locked(res, &iomem_resource, addr,
+						    size, name, 0))
+				break;
+
+			if (dev) {
+				dr->parent = &iomem_resource;
+				dr->start = addr;
+				dr->n = size;
+				devres_add(dev, dr);
+			}
+
+			res->desc = desc;
+			write_unlock(&resource_lock);
+
+
+			/*
+			 * A driver is claiming this region so revoke any
+			 * mappings.
+			 */
+			revoke_iomem(res);
+		} else {
+			res->start = addr;
+			res->end = addr + size - 1;
+			res->name = name;
+			res->desc = desc;
+			res->flags = IORESOURCE_MEM;
+
+			/*
+			 * Only succeed if the resource hosts an exclusive
+			 * range after the insert
+			 */
+			if (__insert_resource(base, res) || res->child)
+				break;
+
+			write_unlock(&resource_lock);
+		}
+
+		return res;
+	}
+	write_unlock(&resource_lock);
+
+	if (flags & GFR_REQUEST_REGION) {
+		free_resource(res);
+		devres_free(dr);
+	} else if (dev)
+		devm_release_action(dev, remove_free_mem_region, res);
+
+	return ERR_PTR(-ERANGE);
+}
+
+/**
+ * devm_request_free_mem_region - find free region for device private memory
+ *
+ * @dev: device struct to bind the resource to
+ * @size: size in bytes of the device memory to add
+ * @base: resource tree to look in
+ *
+ * This function tries to find an empty range of physical address big enough to
+ * contain the new resource, so that it can later be hotplugged as ZONE_DEVICE
+ * memory, which in turn allocates struct pages.
+ */
+struct resource *devm_request_free_mem_region(struct device *dev,
+		struct resource *base, unsigned long size)
+{
+	unsigned long flags = GFR_DESCENDING | GFR_REQUEST_REGION;
+
+	return get_free_mem_region(dev, base, size, GFR_DEFAULT_ALIGN,
+				   dev_name(dev),
+				   IORES_DESC_DEVICE_PRIVATE_MEMORY, flags);
+}
+EXPORT_SYMBOL_GPL(devm_request_free_mem_region);
+
+struct resource *request_free_mem_region(struct resource *base,
+		unsigned long size, const char *name)
+{
+	unsigned long flags = GFR_DESCENDING | GFR_REQUEST_REGION;
+
+	return get_free_mem_region(NULL, base, size, GFR_DEFAULT_ALIGN, name,
+				   IORES_DESC_DEVICE_PRIVATE_MEMORY, flags);
+}
+EXPORT_SYMBOL_GPL(request_free_mem_region);
+
+/**
+ * alloc_free_mem_region - find a free region relative to @base
+ * @base: resource that will parent the new resource
+ * @size: size in bytes of memory to allocate from @base
+ * @align: alignment requirements for the allocation
+ * @name: resource name
+ *
+ * Buses like CXL, that can dynamically instantiate new memory regions,
+ * need a method to allocate physical address space for those regions.
+ * Allocate and insert a new resource to cover a free, unclaimed by a
+ * descendant of @base, range in the span of @base.
+ */
+struct resource *alloc_free_mem_region(struct resource *base,
+				       unsigned long size, unsigned long align,
+				       const char *name)
+{
+	/* Default of ascending direction and insert resource */
+	unsigned long flags = 0;
+
+	return get_free_mem_region(NULL, base, size, align, name,
+				   IORES_DESC_NONE, flags);
+}
+EXPORT_SYMBOL_NS_GPL(alloc_free_mem_region, CXL);
+#endif /* CONFIG_GET_FREE_REGION */
+
+static int __init strict_iomem(char *str)
+{
+	if (strstr(str, "relaxed"))
+		strict_iomem_checks = 0;
+	if (strstr(str, "strict"))
+		strict_iomem_checks = 1;
+	return 1;
+}
+
+static int iomem_fs_init_fs_context(struct fs_context *fc)
+{
+	return init_pseudo(fc, DEVMEM_MAGIC) ? 0 : -ENOMEM;
+}
+
+static struct file_system_type iomem_fs_type = {
+	.name		= "iomem",
+	.owner		= THIS_MODULE,
+	.init_fs_context = iomem_fs_init_fs_context,
+	.kill_sb	= kill_anon_super,
+};
+
+static int __init iomem_init_inode(void)
+{
+	static struct vfsmount *iomem_vfs_mount;
+	static int iomem_fs_cnt;
+	struct inode *inode;
+	int rc;
+
+	rc = simple_pin_fs(&iomem_fs_type, &iomem_vfs_mount, &iomem_fs_cnt);
+	if (rc < 0) {
+		pr_err("Cannot mount iomem pseudo filesystem: %d\n", rc);
+		return rc;
+	}
+
+	inode = alloc_anon_inode(iomem_vfs_mount->mnt_sb);
+	if (IS_ERR(inode)) {
+		rc = PTR_ERR(inode);
+		pr_err("Cannot allocate inode for iomem: %d\n", rc);
+		simple_release_fs(&iomem_vfs_mount, &iomem_fs_cnt);
+		return rc;
+	}
+
+	/*
+	 * Publish iomem revocation inode initialized.
+	 * Pairs with smp_load_acquire() in revoke_iomem().
+	 */
+	smp_store_release(&iomem_inode, inode);
+
+	return 0;
+}
+
+fs_initcall(iomem_init_inode);
+
+__setup("iomem=", strict_iomem);
diff --git a/kernel/resource_kunit.c b/kernel/resource_kunit.c
new file mode 100644
index 000000000..58ab9f914
--- /dev/null
+++ b/kernel/resource_kunit.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Test cases for API provided by resource.c and ioport.h
+ */
+
+#include <kunit/test.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+
+#define R0_START	0x0000
+#define R0_END		0xffff
+#define R1_START	0x1234
+#define R1_END		0x2345
+#define R2_START	0x4567
+#define R2_END		0x5678
+#define R3_START	0x6789
+#define R3_END		0x789a
+#define R4_START	0x2000
+#define R4_END		0x7000
+
+static struct resource r0 = { .start = R0_START, .end = R0_END };
+static struct resource r1 = { .start = R1_START, .end = R1_END };
+static struct resource r2 = { .start = R2_START, .end = R2_END };
+static struct resource r3 = { .start = R3_START, .end = R3_END };
+static struct resource r4 = { .start = R4_START, .end = R4_END };
+
+struct result {
+	struct resource *r1;
+	struct resource *r2;
+	struct resource r;
+	bool ret;
+};
+
+static struct result results_for_union[] = {
+	{
+		.r1 = &r1, .r2 = &r0, .r.start = R0_START, .r.end = R0_END, .ret = true,
+	}, {
+		.r1 = &r2, .r2 = &r0, .r.start = R0_START, .r.end = R0_END, .ret = true,
+	}, {
+		.r1 = &r3, .r2 = &r0, .r.start = R0_START, .r.end = R0_END, .ret = true,
+	}, {
+		.r1 = &r4, .r2 = &r0, .r.start = R0_START, .r.end = R0_END, .ret = true,
+	}, {
+		.r1 = &r2, .r2 = &r1, .ret = false,
+	}, {
+		.r1 = &r3, .r2 = &r1, .ret = false,
+	}, {
+		.r1 = &r4, .r2 = &r1, .r.start = R1_START, .r.end = R4_END, .ret = true,
+	}, {
+		.r1 = &r2, .r2 = &r3, .ret = false,
+	}, {
+		.r1 = &r2, .r2 = &r4, .r.start = R4_START, .r.end = R4_END, .ret = true,
+	}, {
+		.r1 = &r3, .r2 = &r4, .r.start = R4_START, .r.end = R3_END, .ret = true,
+	},
+};
+
+static struct result results_for_intersection[] = {
+	{
+		.r1 = &r1, .r2 = &r0, .r.start = R1_START, .r.end = R1_END, .ret = true,
+	}, {
+		.r1 = &r2, .r2 = &r0, .r.start = R2_START, .r.end = R2_END, .ret = true,
+	}, {
+		.r1 = &r3, .r2 = &r0, .r.start = R3_START, .r.end = R3_END, .ret = true,
+	}, {
+		.r1 = &r4, .r2 = &r0, .r.start = R4_START, .r.end = R4_END, .ret = true,
+	}, {
+		.r1 = &r2, .r2 = &r1, .ret = false,
+	}, {
+		.r1 = &r3, .r2 = &r1, .ret = false,
+	}, {
+		.r1 = &r4, .r2 = &r1, .r.start = R4_START, .r.end = R1_END, .ret = true,
+	}, {
+		.r1 = &r2, .r2 = &r3, .ret = false,
+	}, {
+		.r1 = &r2, .r2 = &r4, .r.start = R2_START, .r.end = R2_END, .ret = true,
+	}, {
+		.r1 = &r3, .r2 = &r4, .r.start = R3_START, .r.end = R4_END, .ret = true,
+	},
+};
+
+static void resource_do_test(struct kunit *test, bool ret, struct resource *r,
+			     bool exp_ret, struct resource *exp_r,
+			     struct resource *r1, struct resource *r2)
+{
+	KUNIT_EXPECT_EQ_MSG(test, ret, exp_ret, "Resources %pR %pR", r1, r2);
+	KUNIT_EXPECT_EQ_MSG(test, r->start, exp_r->start, "Start elements are not equal");
+	KUNIT_EXPECT_EQ_MSG(test, r->end, exp_r->end, "End elements are not equal");
+}
+
+static void resource_do_union_test(struct kunit *test, struct result *r)
+{
+	struct resource result;
+	bool ret;
+
+	memset(&result, 0, sizeof(result));
+	ret = resource_union(r->r1, r->r2, &result);
+	resource_do_test(test, ret, &result, r->ret, &r->r, r->r1, r->r2);
+
+	memset(&result, 0, sizeof(result));
+	ret = resource_union(r->r2, r->r1, &result);
+	resource_do_test(test, ret, &result, r->ret, &r->r, r->r2, r->r1);
+}
+
+static void resource_test_union(struct kunit *test)
+{
+	struct result *r = results_for_union;
+	unsigned int i = 0;
+
+	do {
+		resource_do_union_test(test, &r[i]);
+	} while (++i < ARRAY_SIZE(results_for_union));
+}
+
+static void resource_do_intersection_test(struct kunit *test, struct result *r)
+{
+	struct resource result;
+	bool ret;
+
+	memset(&result, 0, sizeof(result));
+	ret = resource_intersection(r->r1, r->r2, &result);
+	resource_do_test(test, ret, &result, r->ret, &r->r, r->r1, r->r2);
+
+	memset(&result, 0, sizeof(result));
+	ret = resource_intersection(r->r2, r->r1, &result);
+	resource_do_test(test, ret, &result, r->ret, &r->r, r->r2, r->r1);
+}
+
+static void resource_test_intersection(struct kunit *test)
+{
+	struct result *r = results_for_intersection;
+	unsigned int i = 0;
+
+	do {
+		resource_do_intersection_test(test, &r[i]);
+	} while (++i < ARRAY_SIZE(results_for_intersection));
+}
+
+static struct kunit_case resource_test_cases[] = {
+	KUNIT_CASE(resource_test_union),
+	KUNIT_CASE(resource_test_intersection),
+	{}
+};
+
+static struct kunit_suite resource_test_suite = {
+	.name = "resource",
+	.test_cases = resource_test_cases,
+};
+kunit_test_suite(resource_test_suite);
+
+MODULE_LICENSE("GPL");
diff --git a/kernel/rseq.c b/kernel/rseq.c
new file mode 100644
index 000000000..d38ab9441
--- /dev/null
+++ b/kernel/rseq.c
@@ -0,0 +1,395 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Restartable sequences system call
+ *
+ * Copyright (C) 2015, Google, Inc.,
+ * Paul Turner <pjt@google.com> and Andrew Hunter <ahh@google.com>
+ * Copyright (C) 2015-2018, EfficiOS Inc.,
+ * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#include <linux/sched.h>
+#include <linux/uaccess.h>
+#include <linux/syscalls.h>
+#include <linux/rseq.h>
+#include <linux/types.h>
+#include <asm/ptrace.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/rseq.h>
+
+#define RSEQ_CS_NO_RESTART_FLAGS (RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT | \
+				  RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL | \
+				  RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE)
+
+/*
+ *
+ * Restartable sequences are a lightweight interface that allows
+ * user-level code to be executed atomically relative to scheduler
+ * preemption and signal delivery. Typically used for implementing
+ * per-cpu operations.
+ *
+ * It allows user-space to perform update operations on per-cpu data
+ * without requiring heavy-weight atomic operations.
+ *
+ * Detailed algorithm of rseq user-space assembly sequences:
+ *
+ *                     init(rseq_cs)
+ *                     cpu = TLS->rseq::cpu_id_start
+ *   [1]               TLS->rseq::rseq_cs = rseq_cs
+ *   [start_ip]        ----------------------------
+ *   [2]               if (cpu != TLS->rseq::cpu_id)
+ *                             goto abort_ip;
+ *   [3]               <last_instruction_in_cs>
+ *   [post_commit_ip]  ----------------------------
+ *
+ *   The address of jump target abort_ip must be outside the critical
+ *   region, i.e.:
+ *
+ *     [abort_ip] < [start_ip]  || [abort_ip] >= [post_commit_ip]
+ *
+ *   Steps [2]-[3] (inclusive) need to be a sequence of instructions in
+ *   userspace that can handle being interrupted between any of those
+ *   instructions, and then resumed to the abort_ip.
+ *
+ *   1.  Userspace stores the address of the struct rseq_cs assembly
+ *       block descriptor into the rseq_cs field of the registered
+ *       struct rseq TLS area. This update is performed through a single
+ *       store within the inline assembly instruction sequence.
+ *       [start_ip]
+ *
+ *   2.  Userspace tests to check whether the current cpu_id field match
+ *       the cpu number loaded before start_ip, branching to abort_ip
+ *       in case of a mismatch.
+ *
+ *       If the sequence is preempted or interrupted by a signal
+ *       at or after start_ip and before post_commit_ip, then the kernel
+ *       clears TLS->__rseq_abi::rseq_cs, and sets the user-space return
+ *       ip to abort_ip before returning to user-space, so the preempted
+ *       execution resumes at abort_ip.
+ *
+ *   3.  Userspace critical section final instruction before
+ *       post_commit_ip is the commit. The critical section is
+ *       self-terminating.
+ *       [post_commit_ip]
+ *
+ *   4.  <success>
+ *
+ *   On failure at [2], or if interrupted by preempt or signal delivery
+ *   between [1] and [3]:
+ *
+ *       [abort_ip]
+ *   F1. <failure>
+ */
+
+static int rseq_update_cpu_id(struct task_struct *t)
+{
+	u32 cpu_id = raw_smp_processor_id();
+	struct rseq __user *rseq = t->rseq;
+
+	if (!user_write_access_begin(rseq, sizeof(*rseq)))
+		goto efault;
+	unsafe_put_user(cpu_id, &rseq->cpu_id_start, efault_end);
+	unsafe_put_user(cpu_id, &rseq->cpu_id, efault_end);
+	user_write_access_end();
+	trace_rseq_update(t);
+	return 0;
+
+efault_end:
+	user_write_access_end();
+efault:
+	return -EFAULT;
+}
+
+static int rseq_reset_rseq_cpu_id(struct task_struct *t)
+{
+	u32 cpu_id_start = 0, cpu_id = RSEQ_CPU_ID_UNINITIALIZED;
+
+	/*
+	 * Reset cpu_id_start to its initial state (0).
+	 */
+	if (put_user(cpu_id_start, &t->rseq->cpu_id_start))
+		return -EFAULT;
+	/*
+	 * Reset cpu_id to RSEQ_CPU_ID_UNINITIALIZED, so any user coming
+	 * in after unregistration can figure out that rseq needs to be
+	 * registered again.
+	 */
+	if (put_user(cpu_id, &t->rseq->cpu_id))
+		return -EFAULT;
+	return 0;
+}
+
+static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs)
+{
+	struct rseq_cs __user *urseq_cs;
+	u64 ptr;
+	u32 __user *usig;
+	u32 sig;
+	int ret;
+
+#ifdef CONFIG_64BIT
+	if (get_user(ptr, &t->rseq->rseq_cs))
+		return -EFAULT;
+#else
+	if (copy_from_user(&ptr, &t->rseq->rseq_cs, sizeof(ptr)))
+		return -EFAULT;
+#endif
+	if (!ptr) {
+		memset(rseq_cs, 0, sizeof(*rseq_cs));
+		return 0;
+	}
+	if (ptr >= TASK_SIZE)
+		return -EINVAL;
+	urseq_cs = (struct rseq_cs __user *)(unsigned long)ptr;
+	if (copy_from_user(rseq_cs, urseq_cs, sizeof(*rseq_cs)))
+		return -EFAULT;
+
+	if (rseq_cs->start_ip >= TASK_SIZE ||
+	    rseq_cs->start_ip + rseq_cs->post_commit_offset >= TASK_SIZE ||
+	    rseq_cs->abort_ip >= TASK_SIZE ||
+	    rseq_cs->version > 0)
+		return -EINVAL;
+	/* Check for overflow. */
+	if (rseq_cs->start_ip + rseq_cs->post_commit_offset < rseq_cs->start_ip)
+		return -EINVAL;
+	/* Ensure that abort_ip is not in the critical section. */
+	if (rseq_cs->abort_ip - rseq_cs->start_ip < rseq_cs->post_commit_offset)
+		return -EINVAL;
+
+	usig = (u32 __user *)(unsigned long)(rseq_cs->abort_ip - sizeof(u32));
+	ret = get_user(sig, usig);
+	if (ret)
+		return ret;
+
+	if (current->rseq_sig != sig) {
+		printk_ratelimited(KERN_WARNING
+			"Possible attack attempt. Unexpected rseq signature 0x%x, expecting 0x%x (pid=%d, addr=%p).\n",
+			sig, current->rseq_sig, current->pid, usig);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static bool rseq_warn_flags(const char *str, u32 flags)
+{
+	u32 test_flags;
+
+	if (!flags)
+		return false;
+	test_flags = flags & RSEQ_CS_NO_RESTART_FLAGS;
+	if (test_flags)
+		pr_warn_once("Deprecated flags (%u) in %s ABI structure", test_flags, str);
+	test_flags = flags & ~RSEQ_CS_NO_RESTART_FLAGS;
+	if (test_flags)
+		pr_warn_once("Unknown flags (%u) in %s ABI structure", test_flags, str);
+	return true;
+}
+
+static int rseq_need_restart(struct task_struct *t, u32 cs_flags)
+{
+	u32 flags, event_mask;
+	int ret;
+
+	if (rseq_warn_flags("rseq_cs", cs_flags))
+		return -EINVAL;
+
+	/* Get thread flags. */
+	ret = get_user(flags, &t->rseq->flags);
+	if (ret)
+		return ret;
+
+	if (rseq_warn_flags("rseq", flags))
+		return -EINVAL;
+
+	/*
+	 * Load and clear event mask atomically with respect to
+	 * scheduler preemption.
+	 */
+	preempt_disable();
+	event_mask = t->rseq_event_mask;
+	t->rseq_event_mask = 0;
+	preempt_enable();
+
+	return !!event_mask;
+}
+
+static int clear_rseq_cs(struct task_struct *t)
+{
+	/*
+	 * The rseq_cs field is set to NULL on preemption or signal
+	 * delivery on top of rseq assembly block, as well as on top
+	 * of code outside of the rseq assembly block. This performs
+	 * a lazy clear of the rseq_cs field.
+	 *
+	 * Set rseq_cs to NULL.
+	 */
+#ifdef CONFIG_64BIT
+	return put_user(0UL, &t->rseq->rseq_cs);
+#else
+	if (clear_user(&t->rseq->rseq_cs, sizeof(t->rseq->rseq_cs)))
+		return -EFAULT;
+	return 0;
+#endif
+}
+
+/*
+ * Unsigned comparison will be true when ip >= start_ip, and when
+ * ip < start_ip + post_commit_offset.
+ */
+static bool in_rseq_cs(unsigned long ip, struct rseq_cs *rseq_cs)
+{
+	return ip - rseq_cs->start_ip < rseq_cs->post_commit_offset;
+}
+
+static int rseq_ip_fixup(struct pt_regs *regs)
+{
+	unsigned long ip = instruction_pointer(regs);
+	struct task_struct *t = current;
+	struct rseq_cs rseq_cs;
+	int ret;
+
+	ret = rseq_get_rseq_cs(t, &rseq_cs);
+	if (ret)
+		return ret;
+
+	/*
+	 * Handle potentially not being within a critical section.
+	 * If not nested over a rseq critical section, restart is useless.
+	 * Clear the rseq_cs pointer and return.
+	 */
+	if (!in_rseq_cs(ip, &rseq_cs))
+		return clear_rseq_cs(t);
+	ret = rseq_need_restart(t, rseq_cs.flags);
+	if (ret <= 0)
+		return ret;
+	ret = clear_rseq_cs(t);
+	if (ret)
+		return ret;
+	trace_rseq_ip_fixup(ip, rseq_cs.start_ip, rseq_cs.post_commit_offset,
+			    rseq_cs.abort_ip);
+	instruction_pointer_set(regs, (unsigned long)rseq_cs.abort_ip);
+	return 0;
+}
+
+/*
+ * This resume handler must always be executed between any of:
+ * - preemption,
+ * - signal delivery,
+ * and return to user-space.
+ *
+ * This is how we can ensure that the entire rseq critical section
+ * will issue the commit instruction only if executed atomically with
+ * respect to other threads scheduled on the same CPU, and with respect
+ * to signal handlers.
+ */
+void __rseq_handle_notify_resume(struct ksignal *ksig, struct pt_regs *regs)
+{
+	struct task_struct *t = current;
+	int ret, sig;
+
+	if (unlikely(t->flags & PF_EXITING))
+		return;
+
+	/*
+	 * regs is NULL if and only if the caller is in a syscall path.  Skip
+	 * fixup and leave rseq_cs as is so that rseq_sycall() will detect and
+	 * kill a misbehaving userspace on debug kernels.
+	 */
+	if (regs) {
+		ret = rseq_ip_fixup(regs);
+		if (unlikely(ret < 0))
+			goto error;
+	}
+	if (unlikely(rseq_update_cpu_id(t)))
+		goto error;
+	return;
+
+error:
+	sig = ksig ? ksig->sig : 0;
+	force_sigsegv(sig);
+}
+
+#ifdef CONFIG_DEBUG_RSEQ
+
+/*
+ * Terminate the process if a syscall is issued within a restartable
+ * sequence.
+ */
+void rseq_syscall(struct pt_regs *regs)
+{
+	unsigned long ip = instruction_pointer(regs);
+	struct task_struct *t = current;
+	struct rseq_cs rseq_cs;
+
+	if (!t->rseq)
+		return;
+	if (rseq_get_rseq_cs(t, &rseq_cs) || in_rseq_cs(ip, &rseq_cs))
+		force_sig(SIGSEGV);
+}
+
+#endif
+
+/*
+ * sys_rseq - setup restartable sequences for caller thread.
+ */
+SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len,
+		int, flags, u32, sig)
+{
+	int ret;
+
+	if (flags & RSEQ_FLAG_UNREGISTER) {
+		if (flags & ~RSEQ_FLAG_UNREGISTER)
+			return -EINVAL;
+		/* Unregister rseq for current thread. */
+		if (current->rseq != rseq || !current->rseq)
+			return -EINVAL;
+		if (rseq_len != sizeof(*rseq))
+			return -EINVAL;
+		if (current->rseq_sig != sig)
+			return -EPERM;
+		ret = rseq_reset_rseq_cpu_id(current);
+		if (ret)
+			return ret;
+		current->rseq = NULL;
+		current->rseq_sig = 0;
+		return 0;
+	}
+
+	if (unlikely(flags))
+		return -EINVAL;
+
+	if (current->rseq) {
+		/*
+		 * If rseq is already registered, check whether
+		 * the provided address differs from the prior
+		 * one.
+		 */
+		if (current->rseq != rseq || rseq_len != sizeof(*rseq))
+			return -EINVAL;
+		if (current->rseq_sig != sig)
+			return -EPERM;
+		/* Already registered. */
+		return -EBUSY;
+	}
+
+	/*
+	 * If there was no rseq previously registered,
+	 * ensure the provided rseq is properly aligned and valid.
+	 */
+	if (!IS_ALIGNED((unsigned long)rseq, __alignof__(*rseq)) ||
+	    rseq_len != sizeof(*rseq))
+		return -EINVAL;
+	if (!access_ok(rseq, rseq_len))
+		return -EFAULT;
+	current->rseq = rseq;
+	current->rseq_sig = sig;
+	/*
+	 * If rseq was previously inactive, and has just been
+	 * registered, ensure the cpu_id_start and cpu_id fields
+	 * are updated before returning to user-space.
+	 */
+	rseq_set_notify_resume(current);
+
+	return 0;
+}
diff --git a/kernel/scftorture.c b/kernel/scftorture.c
new file mode 100644
index 000000000..83c33ba0c
--- /dev/null
+++ b/kernel/scftorture.c
@@ -0,0 +1,662 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Torture test for smp_call_function() and friends.
+//
+// Copyright (C) Facebook, 2020.
+//
+// Author: Paul E. McKenney <paulmck@kernel.org>
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kthread.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/notifier.h>
+#include <linux/percpu.h>
+#include <linux/rcupdate.h>
+#include <linux/rcupdate_trace.h>
+#include <linux/reboot.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+#include <linux/stat.h>
+#include <linux/srcu.h>
+#include <linux/slab.h>
+#include <linux/torture.h>
+#include <linux/types.h>
+
+#define SCFTORT_STRING "scftorture"
+#define SCFTORT_FLAG SCFTORT_STRING ": "
+
+#define VERBOSE_SCFTORTOUT(s, x...) \
+	do { if (verbose) pr_alert(SCFTORT_FLAG s "\n", ## x); } while (0)
+
+#define SCFTORTOUT_ERRSTRING(s, x...) pr_alert(SCFTORT_FLAG "!!! " s "\n", ## x)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@kernel.org>");
+
+// Wait until there are multiple CPUs before starting test.
+torture_param(int, holdoff, IS_BUILTIN(CONFIG_SCF_TORTURE_TEST) ? 10 : 0,
+	      "Holdoff time before test start (s)");
+torture_param(int, longwait, 0, "Include ridiculously long waits? (seconds)");
+torture_param(int, nthreads, -1, "# threads, defaults to -1 for all CPUs.");
+torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
+torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable");
+torture_param(int, shutdown_secs, 0, "Shutdown time (ms), <= zero to disable.");
+torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s.");
+torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
+torture_param(bool, use_cpus_read_lock, 0, "Use cpus_read_lock() to exclude CPU hotplug.");
+torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
+torture_param(int, weight_resched, -1, "Testing weight for resched_cpu() operations.");
+torture_param(int, weight_single, -1, "Testing weight for single-CPU no-wait operations.");
+torture_param(int, weight_single_rpc, -1, "Testing weight for single-CPU RPC operations.");
+torture_param(int, weight_single_wait, -1, "Testing weight for single-CPU operations.");
+torture_param(int, weight_many, -1, "Testing weight for multi-CPU no-wait operations.");
+torture_param(int, weight_many_wait, -1, "Testing weight for multi-CPU operations.");
+torture_param(int, weight_all, -1, "Testing weight for all-CPU no-wait operations.");
+torture_param(int, weight_all_wait, -1, "Testing weight for all-CPU operations.");
+
+char *torture_type = "";
+
+#ifdef MODULE
+# define SCFTORT_SHUTDOWN 0
+#else
+# define SCFTORT_SHUTDOWN 1
+#endif
+
+torture_param(bool, shutdown, SCFTORT_SHUTDOWN, "Shutdown at end of torture test.");
+
+struct scf_statistics {
+	struct task_struct *task;
+	int cpu;
+	long long n_resched;
+	long long n_single;
+	long long n_single_ofl;
+	long long n_single_rpc;
+	long long n_single_rpc_ofl;
+	long long n_single_wait;
+	long long n_single_wait_ofl;
+	long long n_many;
+	long long n_many_wait;
+	long long n_all;
+	long long n_all_wait;
+};
+
+static struct scf_statistics *scf_stats_p;
+static struct task_struct *scf_torture_stats_task;
+static DEFINE_PER_CPU(long long, scf_invoked_count);
+
+// Data for random primitive selection
+#define SCF_PRIM_RESCHED	0
+#define SCF_PRIM_SINGLE		1
+#define SCF_PRIM_SINGLE_RPC	2
+#define SCF_PRIM_MANY		3
+#define SCF_PRIM_ALL		4
+#define SCF_NPRIMS		8 // Need wait and no-wait versions of each,
+				  //  except for SCF_PRIM_RESCHED and
+				  //  SCF_PRIM_SINGLE_RPC.
+
+static char *scf_prim_name[] = {
+	"resched_cpu",
+	"smp_call_function_single",
+	"smp_call_function_single_rpc",
+	"smp_call_function_many",
+	"smp_call_function",
+};
+
+struct scf_selector {
+	unsigned long scfs_weight;
+	int scfs_prim;
+	bool scfs_wait;
+};
+static struct scf_selector scf_sel_array[SCF_NPRIMS];
+static int scf_sel_array_len;
+static unsigned long scf_sel_totweight;
+
+// Communicate between caller and handler.
+struct scf_check {
+	bool scfc_in;
+	bool scfc_out;
+	int scfc_cpu; // -1 for not _single().
+	bool scfc_wait;
+	bool scfc_rpc;
+	struct completion scfc_completion;
+};
+
+// Use to wait for all threads to start.
+static atomic_t n_started;
+static atomic_t n_errs;
+static atomic_t n_mb_in_errs;
+static atomic_t n_mb_out_errs;
+static atomic_t n_alloc_errs;
+static bool scfdone;
+static char *bangstr = "";
+
+static DEFINE_TORTURE_RANDOM_PERCPU(scf_torture_rand);
+
+extern void resched_cpu(int cpu); // An alternative IPI vector.
+
+// Print torture statistics.  Caller must ensure serialization.
+static void scf_torture_stats_print(void)
+{
+	int cpu;
+	int i;
+	long long invoked_count = 0;
+	bool isdone = READ_ONCE(scfdone);
+	struct scf_statistics scfs = {};
+
+	for_each_possible_cpu(cpu)
+		invoked_count += data_race(per_cpu(scf_invoked_count, cpu));
+	for (i = 0; i < nthreads; i++) {
+		scfs.n_resched += scf_stats_p[i].n_resched;
+		scfs.n_single += scf_stats_p[i].n_single;
+		scfs.n_single_ofl += scf_stats_p[i].n_single_ofl;
+		scfs.n_single_rpc += scf_stats_p[i].n_single_rpc;
+		scfs.n_single_wait += scf_stats_p[i].n_single_wait;
+		scfs.n_single_wait_ofl += scf_stats_p[i].n_single_wait_ofl;
+		scfs.n_many += scf_stats_p[i].n_many;
+		scfs.n_many_wait += scf_stats_p[i].n_many_wait;
+		scfs.n_all += scf_stats_p[i].n_all;
+		scfs.n_all_wait += scf_stats_p[i].n_all_wait;
+	}
+	if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) ||
+	    atomic_read(&n_mb_out_errs) ||
+	    (!IS_ENABLED(CONFIG_KASAN) && atomic_read(&n_alloc_errs)))
+		bangstr = "!!! ";
+	pr_alert("%s %sscf_invoked_count %s: %lld resched: %lld single: %lld/%lld single_ofl: %lld/%lld single_rpc: %lld single_rpc_ofl: %lld many: %lld/%lld all: %lld/%lld ",
+		 SCFTORT_FLAG, bangstr, isdone ? "VER" : "ver", invoked_count, scfs.n_resched,
+		 scfs.n_single, scfs.n_single_wait, scfs.n_single_ofl, scfs.n_single_wait_ofl,
+		 scfs.n_single_rpc, scfs.n_single_rpc_ofl,
+		 scfs.n_many, scfs.n_many_wait, scfs.n_all, scfs.n_all_wait);
+	torture_onoff_stats();
+	pr_cont("ste: %d stnmie: %d stnmoe: %d staf: %d\n", atomic_read(&n_errs),
+		atomic_read(&n_mb_in_errs), atomic_read(&n_mb_out_errs),
+		atomic_read(&n_alloc_errs));
+}
+
+// Periodically prints torture statistics, if periodic statistics printing
+// was specified via the stat_interval module parameter.
+static int
+scf_torture_stats(void *arg)
+{
+	VERBOSE_TOROUT_STRING("scf_torture_stats task started");
+	do {
+		schedule_timeout_interruptible(stat_interval * HZ);
+		scf_torture_stats_print();
+		torture_shutdown_absorb("scf_torture_stats");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("scf_torture_stats");
+	return 0;
+}
+
+// Add a primitive to the scf_sel_array[].
+static void scf_sel_add(unsigned long weight, int prim, bool wait)
+{
+	struct scf_selector *scfsp = &scf_sel_array[scf_sel_array_len];
+
+	// If no weight, if array would overflow, if computing three-place
+	// percentages would overflow, or if the scf_prim_name[] array would
+	// overflow, don't bother.  In the last three two cases, complain.
+	if (!weight ||
+	    WARN_ON_ONCE(scf_sel_array_len >= ARRAY_SIZE(scf_sel_array)) ||
+	    WARN_ON_ONCE(0 - 100000 * weight <= 100000 * scf_sel_totweight) ||
+	    WARN_ON_ONCE(prim >= ARRAY_SIZE(scf_prim_name)))
+		return;
+	scf_sel_totweight += weight;
+	scfsp->scfs_weight = scf_sel_totweight;
+	scfsp->scfs_prim = prim;
+	scfsp->scfs_wait = wait;
+	scf_sel_array_len++;
+}
+
+// Dump out weighting percentages for scf_prim_name[] array.
+static void scf_sel_dump(void)
+{
+	int i;
+	unsigned long oldw = 0;
+	struct scf_selector *scfsp;
+	unsigned long w;
+
+	for (i = 0; i < scf_sel_array_len; i++) {
+		scfsp = &scf_sel_array[i];
+		w = (scfsp->scfs_weight - oldw) * 100000 / scf_sel_totweight;
+		pr_info("%s: %3lu.%03lu %s(%s)\n", __func__, w / 1000, w % 1000,
+			scf_prim_name[scfsp->scfs_prim],
+			scfsp->scfs_wait ? "wait" : "nowait");
+		oldw = scfsp->scfs_weight;
+	}
+}
+
+// Randomly pick a primitive and wait/nowait, based on weightings.
+static struct scf_selector *scf_sel_rand(struct torture_random_state *trsp)
+{
+	int i;
+	unsigned long w = torture_random(trsp) % (scf_sel_totweight + 1);
+
+	for (i = 0; i < scf_sel_array_len; i++)
+		if (scf_sel_array[i].scfs_weight >= w)
+			return &scf_sel_array[i];
+	WARN_ON_ONCE(1);
+	return &scf_sel_array[0];
+}
+
+// Update statistics and occasionally burn up mass quantities of CPU time,
+// if told to do so via scftorture.longwait.  Otherwise, occasionally burn
+// a little bit.
+static void scf_handler(void *scfc_in)
+{
+	int i;
+	int j;
+	unsigned long r = torture_random(this_cpu_ptr(&scf_torture_rand));
+	struct scf_check *scfcp = scfc_in;
+
+	if (likely(scfcp)) {
+		WRITE_ONCE(scfcp->scfc_out, false); // For multiple receivers.
+		if (WARN_ON_ONCE(unlikely(!READ_ONCE(scfcp->scfc_in))))
+			atomic_inc(&n_mb_in_errs);
+	}
+	this_cpu_inc(scf_invoked_count);
+	if (longwait <= 0) {
+		if (!(r & 0xffc0)) {
+			udelay(r & 0x3f);
+			goto out;
+		}
+	}
+	if (r & 0xfff)
+		goto out;
+	r = (r >> 12);
+	if (longwait <= 0) {
+		udelay((r & 0xff) + 1);
+		goto out;
+	}
+	r = r % longwait + 1;
+	for (i = 0; i < r; i++) {
+		for (j = 0; j < 1000; j++) {
+			udelay(1000);
+			cpu_relax();
+		}
+	}
+out:
+	if (unlikely(!scfcp))
+		return;
+	if (scfcp->scfc_wait) {
+		WRITE_ONCE(scfcp->scfc_out, true);
+		if (scfcp->scfc_rpc)
+			complete(&scfcp->scfc_completion);
+	} else {
+		kfree(scfcp);
+	}
+}
+
+// As above, but check for correct CPU.
+static void scf_handler_1(void *scfc_in)
+{
+	struct scf_check *scfcp = scfc_in;
+
+	if (likely(scfcp) && WARN_ONCE(smp_processor_id() != scfcp->scfc_cpu, "%s: Wanted CPU %d got CPU %d\n", __func__, scfcp->scfc_cpu, smp_processor_id())) {
+		atomic_inc(&n_errs);
+	}
+	scf_handler(scfcp);
+}
+
+// Randomly do an smp_call_function*() invocation.
+static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_random_state *trsp)
+{
+	uintptr_t cpu;
+	int ret = 0;
+	struct scf_check *scfcp = NULL;
+	struct scf_selector *scfsp = scf_sel_rand(trsp);
+
+	if (use_cpus_read_lock)
+		cpus_read_lock();
+	else
+		preempt_disable();
+	if (scfsp->scfs_prim == SCF_PRIM_SINGLE || scfsp->scfs_wait) {
+		scfcp = kmalloc(sizeof(*scfcp), GFP_ATOMIC);
+		if (!scfcp) {
+			WARN_ON_ONCE(!IS_ENABLED(CONFIG_KASAN));
+			atomic_inc(&n_alloc_errs);
+		} else {
+			scfcp->scfc_cpu = -1;
+			scfcp->scfc_wait = scfsp->scfs_wait;
+			scfcp->scfc_out = false;
+			scfcp->scfc_rpc = false;
+		}
+	}
+	switch (scfsp->scfs_prim) {
+	case SCF_PRIM_RESCHED:
+		if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST)) {
+			cpu = torture_random(trsp) % nr_cpu_ids;
+			scfp->n_resched++;
+			resched_cpu(cpu);
+			this_cpu_inc(scf_invoked_count);
+		}
+		break;
+	case SCF_PRIM_SINGLE:
+		cpu = torture_random(trsp) % nr_cpu_ids;
+		if (scfsp->scfs_wait)
+			scfp->n_single_wait++;
+		else
+			scfp->n_single++;
+		if (scfcp) {
+			scfcp->scfc_cpu = cpu;
+			barrier(); // Prevent race-reduction compiler optimizations.
+			scfcp->scfc_in = true;
+		}
+		ret = smp_call_function_single(cpu, scf_handler_1, (void *)scfcp, scfsp->scfs_wait);
+		if (ret) {
+			if (scfsp->scfs_wait)
+				scfp->n_single_wait_ofl++;
+			else
+				scfp->n_single_ofl++;
+			kfree(scfcp);
+			scfcp = NULL;
+		}
+		break;
+	case SCF_PRIM_SINGLE_RPC:
+		if (!scfcp)
+			break;
+		cpu = torture_random(trsp) % nr_cpu_ids;
+		scfp->n_single_rpc++;
+		scfcp->scfc_cpu = cpu;
+		scfcp->scfc_wait = true;
+		init_completion(&scfcp->scfc_completion);
+		scfcp->scfc_rpc = true;
+		barrier(); // Prevent race-reduction compiler optimizations.
+		scfcp->scfc_in = true;
+		ret = smp_call_function_single(cpu, scf_handler_1, (void *)scfcp, 0);
+		if (!ret) {
+			if (use_cpus_read_lock)
+				cpus_read_unlock();
+			else
+				preempt_enable();
+			wait_for_completion(&scfcp->scfc_completion);
+			if (use_cpus_read_lock)
+				cpus_read_lock();
+			else
+				preempt_disable();
+		} else {
+			scfp->n_single_rpc_ofl++;
+			kfree(scfcp);
+			scfcp = NULL;
+		}
+		break;
+	case SCF_PRIM_MANY:
+		if (scfsp->scfs_wait)
+			scfp->n_many_wait++;
+		else
+			scfp->n_many++;
+		if (scfcp) {
+			barrier(); // Prevent race-reduction compiler optimizations.
+			scfcp->scfc_in = true;
+		}
+		smp_call_function_many(cpu_online_mask, scf_handler, scfcp, scfsp->scfs_wait);
+		break;
+	case SCF_PRIM_ALL:
+		if (scfsp->scfs_wait)
+			scfp->n_all_wait++;
+		else
+			scfp->n_all++;
+		if (scfcp) {
+			barrier(); // Prevent race-reduction compiler optimizations.
+			scfcp->scfc_in = true;
+		}
+		smp_call_function(scf_handler, scfcp, scfsp->scfs_wait);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		if (scfcp)
+			scfcp->scfc_out = true;
+	}
+	if (scfcp && scfsp->scfs_wait) {
+		if (WARN_ON_ONCE((num_online_cpus() > 1 || scfsp->scfs_prim == SCF_PRIM_SINGLE) &&
+				 !scfcp->scfc_out)) {
+			pr_warn("%s: Memory-ordering failure, scfs_prim: %d.\n", __func__, scfsp->scfs_prim);
+			atomic_inc(&n_mb_out_errs); // Leak rather than trash!
+		} else {
+			kfree(scfcp);
+		}
+		barrier(); // Prevent race-reduction compiler optimizations.
+	}
+	if (use_cpus_read_lock)
+		cpus_read_unlock();
+	else
+		preempt_enable();
+	if (!(torture_random(trsp) & 0xfff))
+		schedule_timeout_uninterruptible(1);
+}
+
+// SCF test kthread.  Repeatedly does calls to members of the
+// smp_call_function() family of functions.
+static int scftorture_invoker(void *arg)
+{
+	int cpu;
+	int curcpu;
+	DEFINE_TORTURE_RANDOM(rand);
+	struct scf_statistics *scfp = (struct scf_statistics *)arg;
+	bool was_offline = false;
+
+	VERBOSE_SCFTORTOUT("scftorture_invoker %d: task started", scfp->cpu);
+	cpu = scfp->cpu % nr_cpu_ids;
+	WARN_ON_ONCE(set_cpus_allowed_ptr(current, cpumask_of(cpu)));
+	set_user_nice(current, MAX_NICE);
+	if (holdoff)
+		schedule_timeout_interruptible(holdoff * HZ);
+
+	VERBOSE_SCFTORTOUT("scftorture_invoker %d: Waiting for all SCF torturers from cpu %d", scfp->cpu, raw_smp_processor_id());
+
+	// Make sure that the CPU is affinitized appropriately during testing.
+	curcpu = raw_smp_processor_id();
+	WARN_ONCE(curcpu != scfp->cpu % nr_cpu_ids,
+		  "%s: Wanted CPU %d, running on %d, nr_cpu_ids = %d\n",
+		  __func__, scfp->cpu, curcpu, nr_cpu_ids);
+
+	if (!atomic_dec_return(&n_started))
+		while (atomic_read_acquire(&n_started)) {
+			if (torture_must_stop()) {
+				VERBOSE_SCFTORTOUT("scftorture_invoker %d ended before starting", scfp->cpu);
+				goto end;
+			}
+			schedule_timeout_uninterruptible(1);
+		}
+
+	VERBOSE_SCFTORTOUT("scftorture_invoker %d started", scfp->cpu);
+
+	do {
+		scftorture_invoke_one(scfp, &rand);
+		while (cpu_is_offline(cpu) && !torture_must_stop()) {
+			schedule_timeout_interruptible(HZ / 5);
+			was_offline = true;
+		}
+		if (was_offline) {
+			set_cpus_allowed_ptr(current, cpumask_of(cpu));
+			was_offline = false;
+		}
+		cond_resched();
+		stutter_wait("scftorture_invoker");
+	} while (!torture_must_stop());
+
+	VERBOSE_SCFTORTOUT("scftorture_invoker %d ended", scfp->cpu);
+end:
+	torture_kthread_stopping("scftorture_invoker");
+	return 0;
+}
+
+static void
+scftorture_print_module_parms(const char *tag)
+{
+	pr_alert(SCFTORT_FLAG
+		 "--- %s:  verbose=%d holdoff=%d longwait=%d nthreads=%d onoff_holdoff=%d onoff_interval=%d shutdown_secs=%d stat_interval=%d stutter=%d use_cpus_read_lock=%d, weight_resched=%d, weight_single=%d, weight_single_rpc=%d, weight_single_wait=%d, weight_many=%d, weight_many_wait=%d, weight_all=%d, weight_all_wait=%d\n", tag,
+		 verbose, holdoff, longwait, nthreads, onoff_holdoff, onoff_interval, shutdown, stat_interval, stutter, use_cpus_read_lock, weight_resched, weight_single, weight_single_rpc, weight_single_wait, weight_many, weight_many_wait, weight_all, weight_all_wait);
+}
+
+static void scf_cleanup_handler(void *unused)
+{
+}
+
+static void scf_torture_cleanup(void)
+{
+	int i;
+
+	if (torture_cleanup_begin())
+		return;
+
+	WRITE_ONCE(scfdone, true);
+	if (nthreads && scf_stats_p)
+		for (i = 0; i < nthreads; i++)
+			torture_stop_kthread("scftorture_invoker", scf_stats_p[i].task);
+	else
+		goto end;
+	smp_call_function(scf_cleanup_handler, NULL, 0);
+	torture_stop_kthread(scf_torture_stats, scf_torture_stats_task);
+	scf_torture_stats_print();  // -After- the stats thread is stopped!
+	kfree(scf_stats_p);  // -After- the last stats print has completed!
+	scf_stats_p = NULL;
+
+	if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) || atomic_read(&n_mb_out_errs))
+		scftorture_print_module_parms("End of test: FAILURE");
+	else if (torture_onoff_failures())
+		scftorture_print_module_parms("End of test: LOCK_HOTPLUG");
+	else
+		scftorture_print_module_parms("End of test: SUCCESS");
+
+end:
+	torture_cleanup_end();
+}
+
+static int __init scf_torture_init(void)
+{
+	long i;
+	int firsterr = 0;
+	unsigned long weight_resched1 = weight_resched;
+	unsigned long weight_single1 = weight_single;
+	unsigned long weight_single_rpc1 = weight_single_rpc;
+	unsigned long weight_single_wait1 = weight_single_wait;
+	unsigned long weight_many1 = weight_many;
+	unsigned long weight_many_wait1 = weight_many_wait;
+	unsigned long weight_all1 = weight_all;
+	unsigned long weight_all_wait1 = weight_all_wait;
+
+	if (!torture_init_begin(SCFTORT_STRING, verbose))
+		return -EBUSY;
+
+	scftorture_print_module_parms("Start of test");
+
+	if (weight_resched <= 0 &&
+	    weight_single <= 0 && weight_single_rpc <= 0 && weight_single_wait <= 0 &&
+	    weight_many <= 0 && weight_many_wait <= 0 &&
+	    weight_all <= 0 && weight_all_wait <= 0) {
+		weight_resched1 = weight_resched == 0 ? 0 : 2 * nr_cpu_ids;
+		weight_single1 = weight_single == 0 ? 0 : 2 * nr_cpu_ids;
+		weight_single_rpc1 = weight_single_rpc == 0 ? 0 : 2 * nr_cpu_ids;
+		weight_single_wait1 = weight_single_wait == 0 ? 0 : 2 * nr_cpu_ids;
+		weight_many1 = weight_many == 0 ? 0 : 2;
+		weight_many_wait1 = weight_many_wait == 0 ? 0 : 2;
+		weight_all1 = weight_all == 0 ? 0 : 1;
+		weight_all_wait1 = weight_all_wait == 0 ? 0 : 1;
+	} else {
+		if (weight_resched == -1)
+			weight_resched1 = 0;
+		if (weight_single == -1)
+			weight_single1 = 0;
+		if (weight_single_rpc == -1)
+			weight_single_rpc1 = 0;
+		if (weight_single_wait == -1)
+			weight_single_wait1 = 0;
+		if (weight_many == -1)
+			weight_many1 = 0;
+		if (weight_many_wait == -1)
+			weight_many_wait1 = 0;
+		if (weight_all == -1)
+			weight_all1 = 0;
+		if (weight_all_wait == -1)
+			weight_all_wait1 = 0;
+	}
+	if (weight_resched1 == 0 && weight_single1 == 0 && weight_single_rpc1 == 0 &&
+	    weight_single_wait1 == 0 && weight_many1 == 0 && weight_many_wait1 == 0 &&
+	    weight_all1 == 0 && weight_all_wait1 == 0) {
+		SCFTORTOUT_ERRSTRING("all zero weights makes no sense");
+		firsterr = -EINVAL;
+		goto unwind;
+	}
+	if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST))
+		scf_sel_add(weight_resched1, SCF_PRIM_RESCHED, false);
+	else if (weight_resched1)
+		SCFTORTOUT_ERRSTRING("built as module, weight_resched ignored");
+	scf_sel_add(weight_single1, SCF_PRIM_SINGLE, false);
+	scf_sel_add(weight_single_rpc1, SCF_PRIM_SINGLE_RPC, true);
+	scf_sel_add(weight_single_wait1, SCF_PRIM_SINGLE, true);
+	scf_sel_add(weight_many1, SCF_PRIM_MANY, false);
+	scf_sel_add(weight_many_wait1, SCF_PRIM_MANY, true);
+	scf_sel_add(weight_all1, SCF_PRIM_ALL, false);
+	scf_sel_add(weight_all_wait1, SCF_PRIM_ALL, true);
+	scf_sel_dump();
+
+	if (onoff_interval > 0) {
+		firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, NULL);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	if (shutdown_secs > 0) {
+		firsterr = torture_shutdown_init(shutdown_secs, scf_torture_cleanup);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	if (stutter > 0) {
+		firsterr = torture_stutter_init(stutter, stutter);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+
+	// Worker tasks invoking smp_call_function().
+	if (nthreads < 0)
+		nthreads = num_online_cpus();
+	scf_stats_p = kcalloc(nthreads, sizeof(scf_stats_p[0]), GFP_KERNEL);
+	if (!scf_stats_p) {
+		SCFTORTOUT_ERRSTRING("out of memory");
+		firsterr = -ENOMEM;
+		goto unwind;
+	}
+
+	VERBOSE_SCFTORTOUT("Starting %d smp_call_function() threads", nthreads);
+
+	atomic_set(&n_started, nthreads);
+	for (i = 0; i < nthreads; i++) {
+		scf_stats_p[i].cpu = i;
+		firsterr = torture_create_kthread(scftorture_invoker, (void *)&scf_stats_p[i],
+						  scf_stats_p[i].task);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+	if (stat_interval > 0) {
+		firsterr = torture_create_kthread(scf_torture_stats, NULL, scf_torture_stats_task);
+		if (torture_init_error(firsterr))
+			goto unwind;
+	}
+
+	torture_init_end();
+	return 0;
+
+unwind:
+	torture_init_end();
+	scf_torture_cleanup();
+	if (shutdown_secs) {
+		WARN_ON(!IS_MODULE(CONFIG_SCF_TORTURE_TEST));
+		kernel_power_off();
+	}
+	return firsterr;
+}
+
+module_init(scf_torture_init);
+module_exit(scf_torture_cleanup);
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
new file mode 100644
index 000000000..976092b7b
--- /dev/null
+++ b/kernel/sched/Makefile
@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# The compilers are complaining about unused variables inside an if(0) scope
+# block. This is daft, shut them up.
+ccflags-y += $(call cc-disable-warning, unused-but-set-variable)
+
+# These files are disabled because they produce non-interesting flaky coverage
+# that is not a function of syscall inputs. E.g. involuntary context switches.
+KCOV_INSTRUMENT := n
+
+# Disable KCSAN to avoid excessive noise and performance degradation. To avoid
+# false positives ensure barriers implied by sched functions are instrumented.
+KCSAN_SANITIZE := n
+KCSAN_INSTRUMENT_BARRIERS := y
+
+ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y)
+# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
+# needed for x86 only.  Why this used to be enabled for all architectures is beyond
+# me.  I suspect most platforms don't need this, but until we know that for sure
+# I turn this off for IA-64 only.  Andreas Schwab says it's also needed on m68k
+# to get a correct value for the wait-channel (WCHAN in ps). --davidm
+CFLAGS_core.o := $(PROFILING) -fno-omit-frame-pointer
+endif
+
+#
+# Build efficiency:
+#
+# These compilation units have roughly the same size and complexity - so their
+# build parallelizes well and finishes roughly at once:
+#
+obj-y += core.o
+obj-y += fair.o
+obj-y += build_policy.o
+obj-y += build_utility.o
diff --git a/kernel/sched/autogroup.c b/kernel/sched/autogroup.c
new file mode 100644
index 000000000..991fc9002
--- /dev/null
+++ b/kernel/sched/autogroup.c
@@ -0,0 +1,291 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Auto-group scheduling implementation:
+ */
+
+unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1;
+static struct autogroup autogroup_default;
+static atomic_t autogroup_seq_nr;
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table sched_autogroup_sysctls[] = {
+	{
+		.procname       = "sched_autogroup_enabled",
+		.data           = &sysctl_sched_autogroup_enabled,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec_minmax,
+		.extra1         = SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE,
+	},
+	{}
+};
+
+static void __init sched_autogroup_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_autogroup_sysctls);
+}
+#else
+#define sched_autogroup_sysctl_init() do { } while (0)
+#endif
+
+void __init autogroup_init(struct task_struct *init_task)
+{
+	autogroup_default.tg = &root_task_group;
+	kref_init(&autogroup_default.kref);
+	init_rwsem(&autogroup_default.lock);
+	init_task->signal->autogroup = &autogroup_default;
+	sched_autogroup_sysctl_init();
+}
+
+void autogroup_free(struct task_group *tg)
+{
+	kfree(tg->autogroup);
+}
+
+static inline void autogroup_destroy(struct kref *kref)
+{
+	struct autogroup *ag = container_of(kref, struct autogroup, kref);
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	/* We've redirected RT tasks to the root task group... */
+	ag->tg->rt_se = NULL;
+	ag->tg->rt_rq = NULL;
+#endif
+	sched_release_group(ag->tg);
+	sched_destroy_group(ag->tg);
+}
+
+static inline void autogroup_kref_put(struct autogroup *ag)
+{
+	kref_put(&ag->kref, autogroup_destroy);
+}
+
+static inline struct autogroup *autogroup_kref_get(struct autogroup *ag)
+{
+	kref_get(&ag->kref);
+	return ag;
+}
+
+static inline struct autogroup *autogroup_task_get(struct task_struct *p)
+{
+	struct autogroup *ag;
+	unsigned long flags;
+
+	if (!lock_task_sighand(p, &flags))
+		return autogroup_kref_get(&autogroup_default);
+
+	ag = autogroup_kref_get(p->signal->autogroup);
+	unlock_task_sighand(p, &flags);
+
+	return ag;
+}
+
+static inline struct autogroup *autogroup_create(void)
+{
+	struct autogroup *ag = kzalloc(sizeof(*ag), GFP_KERNEL);
+	struct task_group *tg;
+
+	if (!ag)
+		goto out_fail;
+
+	tg = sched_create_group(&root_task_group);
+	if (IS_ERR(tg))
+		goto out_free;
+
+	kref_init(&ag->kref);
+	init_rwsem(&ag->lock);
+	ag->id = atomic_inc_return(&autogroup_seq_nr);
+	ag->tg = tg;
+#ifdef CONFIG_RT_GROUP_SCHED
+	/*
+	 * Autogroup RT tasks are redirected to the root task group
+	 * so we don't have to move tasks around upon policy change,
+	 * or flail around trying to allocate bandwidth on the fly.
+	 * A bandwidth exception in __sched_setscheduler() allows
+	 * the policy change to proceed.
+	 */
+	free_rt_sched_group(tg);
+	tg->rt_se = root_task_group.rt_se;
+	tg->rt_rq = root_task_group.rt_rq;
+#endif
+	tg->autogroup = ag;
+
+	sched_online_group(tg, &root_task_group);
+	return ag;
+
+out_free:
+	kfree(ag);
+out_fail:
+	if (printk_ratelimit()) {
+		printk(KERN_WARNING "autogroup_create: %s failure.\n",
+			ag ? "sched_create_group()" : "kzalloc()");
+	}
+
+	return autogroup_kref_get(&autogroup_default);
+}
+
+bool task_wants_autogroup(struct task_struct *p, struct task_group *tg)
+{
+	if (tg != &root_task_group)
+		return false;
+	/*
+	 * If we race with autogroup_move_group() the caller can use the old
+	 * value of signal->autogroup but in this case sched_move_task() will
+	 * be called again before autogroup_kref_put().
+	 *
+	 * However, there is no way sched_autogroup_exit_task() could tell us
+	 * to avoid autogroup->tg, so we abuse PF_EXITING flag for this case.
+	 */
+	if (p->flags & PF_EXITING)
+		return false;
+
+	return true;
+}
+
+void sched_autogroup_exit_task(struct task_struct *p)
+{
+	/*
+	 * We are going to call exit_notify() and autogroup_move_group() can't
+	 * see this thread after that: we can no longer use signal->autogroup.
+	 * See the PF_EXITING check in task_wants_autogroup().
+	 */
+	sched_move_task(p);
+}
+
+static void
+autogroup_move_group(struct task_struct *p, struct autogroup *ag)
+{
+	struct autogroup *prev;
+	struct task_struct *t;
+	unsigned long flags;
+
+	if (WARN_ON_ONCE(!lock_task_sighand(p, &flags)))
+		return;
+
+	prev = p->signal->autogroup;
+	if (prev == ag) {
+		unlock_task_sighand(p, &flags);
+		return;
+	}
+
+	p->signal->autogroup = autogroup_kref_get(ag);
+	/*
+	 * We can't avoid sched_move_task() after we changed signal->autogroup,
+	 * this process can already run with task_group() == prev->tg or we can
+	 * race with cgroup code which can read autogroup = prev under rq->lock.
+	 * In the latter case for_each_thread() can not miss a migrating thread,
+	 * cpu_cgroup_attach() must not be possible after cgroup_exit() and it
+	 * can't be removed from thread list, we hold ->siglock.
+	 *
+	 * If an exiting thread was already removed from thread list we rely on
+	 * sched_autogroup_exit_task().
+	 */
+	for_each_thread(p, t)
+		sched_move_task(t);
+
+	unlock_task_sighand(p, &flags);
+	autogroup_kref_put(prev);
+}
+
+/* Allocates GFP_KERNEL, cannot be called under any spinlock: */
+void sched_autogroup_create_attach(struct task_struct *p)
+{
+	struct autogroup *ag = autogroup_create();
+
+	autogroup_move_group(p, ag);
+
+	/* Drop extra reference added by autogroup_create(): */
+	autogroup_kref_put(ag);
+}
+EXPORT_SYMBOL(sched_autogroup_create_attach);
+
+/* Cannot be called under siglock. Currently has no users: */
+void sched_autogroup_detach(struct task_struct *p)
+{
+	autogroup_move_group(p, &autogroup_default);
+}
+EXPORT_SYMBOL(sched_autogroup_detach);
+
+void sched_autogroup_fork(struct signal_struct *sig)
+{
+	sig->autogroup = autogroup_task_get(current);
+}
+
+void sched_autogroup_exit(struct signal_struct *sig)
+{
+	autogroup_kref_put(sig->autogroup);
+}
+
+static int __init setup_autogroup(char *str)
+{
+	sysctl_sched_autogroup_enabled = 0;
+
+	return 1;
+}
+__setup("noautogroup", setup_autogroup);
+
+#ifdef CONFIG_PROC_FS
+
+int proc_sched_autogroup_set_nice(struct task_struct *p, int nice)
+{
+	static unsigned long next = INITIAL_JIFFIES;
+	struct autogroup *ag;
+	unsigned long shares;
+	int err, idx;
+
+	if (nice < MIN_NICE || nice > MAX_NICE)
+		return -EINVAL;
+
+	err = security_task_setnice(current, nice);
+	if (err)
+		return err;
+
+	if (nice < 0 && !can_nice(current, nice))
+		return -EPERM;
+
+	/* This is a heavy operation, taking global locks.. */
+	if (!capable(CAP_SYS_ADMIN) && time_before(jiffies, next))
+		return -EAGAIN;
+
+	next = HZ / 10 + jiffies;
+	ag = autogroup_task_get(p);
+
+	idx = array_index_nospec(nice + 20, 40);
+	shares = scale_load(sched_prio_to_weight[idx]);
+
+	down_write(&ag->lock);
+	err = sched_group_set_shares(ag->tg, shares);
+	if (!err)
+		ag->nice = nice;
+	up_write(&ag->lock);
+
+	autogroup_kref_put(ag);
+
+	return err;
+}
+
+void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)
+{
+	struct autogroup *ag = autogroup_task_get(p);
+
+	if (!task_group_is_autogroup(ag->tg))
+		goto out;
+
+	down_read(&ag->lock);
+	seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice);
+	up_read(&ag->lock);
+
+out:
+	autogroup_kref_put(ag);
+}
+#endif /* CONFIG_PROC_FS */
+
+int autogroup_path(struct task_group *tg, char *buf, int buflen)
+{
+	if (!task_group_is_autogroup(tg))
+		return 0;
+
+	return snprintf(buf, buflen, "%s-%ld", "/autogroup", tg->autogroup->id);
+}
diff --git a/kernel/sched/autogroup.h b/kernel/sched/autogroup.h
new file mode 100644
index 000000000..90d69f2c5
--- /dev/null
+++ b/kernel/sched/autogroup.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _KERNEL_SCHED_AUTOGROUP_H
+#define _KERNEL_SCHED_AUTOGROUP_H
+
+#ifdef CONFIG_SCHED_AUTOGROUP
+
+struct autogroup {
+	/*
+	 * Reference doesn't mean how many threads attach to this
+	 * autogroup now. It just stands for the number of tasks
+	 * which could use this autogroup.
+	 */
+	struct kref		kref;
+	struct task_group	*tg;
+	struct rw_semaphore	lock;
+	unsigned long		id;
+	int			nice;
+};
+
+extern void autogroup_init(struct task_struct *init_task);
+extern void autogroup_free(struct task_group *tg);
+
+static inline bool task_group_is_autogroup(struct task_group *tg)
+{
+	return !!tg->autogroup;
+}
+
+extern bool task_wants_autogroup(struct task_struct *p, struct task_group *tg);
+
+static inline struct task_group *
+autogroup_task_group(struct task_struct *p, struct task_group *tg)
+{
+	extern unsigned int sysctl_sched_autogroup_enabled;
+	int enabled = READ_ONCE(sysctl_sched_autogroup_enabled);
+
+	if (enabled && task_wants_autogroup(p, tg))
+		return p->signal->autogroup->tg;
+
+	return tg;
+}
+
+extern int autogroup_path(struct task_group *tg, char *buf, int buflen);
+
+#else /* !CONFIG_SCHED_AUTOGROUP */
+
+static inline void autogroup_init(struct task_struct *init_task) {  }
+static inline void autogroup_free(struct task_group *tg) { }
+static inline bool task_group_is_autogroup(struct task_group *tg)
+{
+	return 0;
+}
+
+static inline struct task_group *
+autogroup_task_group(struct task_struct *p, struct task_group *tg)
+{
+	return tg;
+}
+
+static inline int autogroup_path(struct task_group *tg, char *buf, int buflen)
+{
+	return 0;
+}
+
+#endif /* CONFIG_SCHED_AUTOGROUP */
+
+#endif /* _KERNEL_SCHED_AUTOGROUP_H */
diff --git a/kernel/sched/build_policy.c b/kernel/sched/build_policy.c
new file mode 100644
index 000000000..d9dc9ab37
--- /dev/null
+++ b/kernel/sched/build_policy.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * These are the scheduling policy related scheduler files, built
+ * in a single compilation unit for build efficiency reasons.
+ *
+ * ( Incidentally, the size of the compilation unit is roughly
+ *   comparable to core.c and fair.c, the other two big
+ *   compilation units. This helps balance build time, while
+ *   coalescing source files to amortize header inclusion
+ *   cost. )
+ *
+ * core.c and fair.c are built separately.
+ */
+
+/* Headers: */
+#include <linux/sched/clock.h>
+#include <linux/sched/cputime.h>
+#include <linux/sched/hotplug.h>
+#include <linux/sched/posix-timers.h>
+#include <linux/sched/rt.h>
+
+#include <linux/cpuidle.h>
+#include <linux/jiffies.h>
+#include <linux/livepatch.h>
+#include <linux/psi.h>
+#include <linux/seqlock_api.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+#include <linux/tsacct_kern.h>
+#include <linux/vtime.h>
+
+#include <uapi/linux/sched/types.h>
+
+#include "sched.h"
+#include "smp.h"
+
+#include "autogroup.h"
+#include "stats.h"
+#include "pelt.h"
+
+/* Source code modules: */
+
+#include "idle.c"
+
+#include "rt.c"
+
+#ifdef CONFIG_SMP
+# include "cpudeadline.c"
+# include "pelt.c"
+#endif
+
+#include "cputime.c"
+#include "deadline.c"
+
diff --git a/kernel/sched/build_utility.c b/kernel/sched/build_utility.c
new file mode 100644
index 000000000..99bdd96f4
--- /dev/null
+++ b/kernel/sched/build_utility.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * These are various utility functions of the scheduler,
+ * built in a single compilation unit for build efficiency reasons.
+ *
+ * ( Incidentally, the size of the compilation unit is roughly
+ *   comparable to core.c, fair.c, smp.c and policy.c, the other
+ *   big compilation units. This helps balance build time, while
+ *   coalescing source files to amortize header inclusion
+ *   cost. )
+ */
+#include <linux/sched/clock.h>
+#include <linux/sched/cputime.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/isolation.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/nohz.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/rseq_api.h>
+#include <linux/sched/task_stack.h>
+
+#include <linux/cpufreq.h>
+#include <linux/cpumask_api.h>
+#include <linux/cpuset.h>
+#include <linux/ctype.h>
+#include <linux/debugfs.h>
+#include <linux/energy_model.h>
+#include <linux/hashtable_api.h>
+#include <linux/irq.h>
+#include <linux/kobject_api.h>
+#include <linux/membarrier.h>
+#include <linux/mempolicy.h>
+#include <linux/nmi.h>
+#include <linux/nospec.h>
+#include <linux/proc_fs.h>
+#include <linux/psi.h>
+#include <linux/psi.h>
+#include <linux/ptrace_api.h>
+#include <linux/sched_clock.h>
+#include <linux/security.h>
+#include <linux/spinlock_api.h>
+#include <linux/swait_api.h>
+#include <linux/timex.h>
+#include <linux/utsname.h>
+#include <linux/wait_api.h>
+#include <linux/workqueue_api.h>
+
+#include <uapi/linux/prctl.h>
+#include <uapi/linux/sched/types.h>
+
+#include <asm/switch_to.h>
+
+#include "sched.h"
+#include "sched-pelt.h"
+#include "stats.h"
+#include "autogroup.h"
+
+#include "clock.c"
+
+#ifdef CONFIG_CGROUP_CPUACCT
+# include "cpuacct.c"
+#endif
+
+#ifdef CONFIG_CPU_FREQ
+# include "cpufreq.c"
+#endif
+
+#ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
+# include "cpufreq_schedutil.c"
+#endif
+
+#ifdef CONFIG_SCHED_DEBUG
+# include "debug.c"
+#endif
+
+#ifdef CONFIG_SCHEDSTATS
+# include "stats.c"
+#endif
+
+#include "loadavg.c"
+#include "completion.c"
+#include "swait.c"
+#include "wait_bit.c"
+#include "wait.c"
+
+#ifdef CONFIG_SMP
+# include "cpupri.c"
+# include "stop_task.c"
+# include "topology.c"
+#endif
+
+#ifdef CONFIG_SCHED_CORE
+# include "core_sched.c"
+#endif
+
+#ifdef CONFIG_PSI
+# include "psi.c"
+#endif
+
+#ifdef CONFIG_MEMBARRIER
+# include "membarrier.c"
+#endif
+
+#ifdef CONFIG_CPU_ISOLATION
+# include "isolation.c"
+#endif
+
+#ifdef CONFIG_SCHED_AUTOGROUP
+# include "autogroup.c"
+#endif
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
new file mode 100644
index 000000000..e374c0c92
--- /dev/null
+++ b/kernel/sched/clock.c
@@ -0,0 +1,480 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sched_clock() for unstable CPU clocks
+ *
+ *  Copyright (C) 2008 Red Hat, Inc., Peter Zijlstra
+ *
+ *  Updates and enhancements:
+ *    Copyright (C) 2008 Red Hat, Inc. Steven Rostedt <srostedt@redhat.com>
+ *
+ * Based on code by:
+ *   Ingo Molnar <mingo@redhat.com>
+ *   Guillaume Chazarain <guichaz@gmail.com>
+ *
+ *
+ * What this file implements:
+ *
+ * cpu_clock(i) provides a fast (execution time) high resolution
+ * clock with bounded drift between CPUs. The value of cpu_clock(i)
+ * is monotonic for constant i. The timestamp returned is in nanoseconds.
+ *
+ * ######################### BIG FAT WARNING ##########################
+ * # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
+ * # go backwards !!                                                  #
+ * ####################################################################
+ *
+ * There is no strict promise about the base, although it tends to start
+ * at 0 on boot (but people really shouldn't rely on that).
+ *
+ * cpu_clock(i)       -- can be used from any context, including NMI.
+ * local_clock()      -- is cpu_clock() on the current CPU.
+ *
+ * sched_clock_cpu(i)
+ *
+ * How it is implemented:
+ *
+ * The implementation either uses sched_clock() when
+ * !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK, which means in that case the
+ * sched_clock() is assumed to provide these properties (mostly it means
+ * the architecture provides a globally synchronized highres time source).
+ *
+ * Otherwise it tries to create a semi stable clock from a mixture of other
+ * clocks, including:
+ *
+ *  - GTOD (clock monotonic)
+ *  - sched_clock()
+ *  - explicit idle events
+ *
+ * We use GTOD as base and use sched_clock() deltas to improve resolution. The
+ * deltas are filtered to provide monotonicity and keeping it within an
+ * expected window.
+ *
+ * Furthermore, explicit sleep and wakeup hooks allow us to account for time
+ * that is otherwise invisible (TSC gets stopped).
+ *
+ */
+
+/*
+ * Scheduler clock - returns current time in nanosec units.
+ * This is default implementation.
+ * Architectures and sub-architectures can override this.
+ */
+notrace unsigned long long __weak sched_clock(void)
+{
+	return (unsigned long long)(jiffies - INITIAL_JIFFIES)
+					* (NSEC_PER_SEC / HZ);
+}
+EXPORT_SYMBOL_GPL(sched_clock);
+
+static DEFINE_STATIC_KEY_FALSE(sched_clock_running);
+
+#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
+/*
+ * We must start with !__sched_clock_stable because the unstable -> stable
+ * transition is accurate, while the stable -> unstable transition is not.
+ *
+ * Similarly we start with __sched_clock_stable_early, thereby assuming we
+ * will become stable, such that there's only a single 1 -> 0 transition.
+ */
+static DEFINE_STATIC_KEY_FALSE(__sched_clock_stable);
+static int __sched_clock_stable_early = 1;
+
+/*
+ * We want: ktime_get_ns() + __gtod_offset == sched_clock() + __sched_clock_offset
+ */
+__read_mostly u64 __sched_clock_offset;
+static __read_mostly u64 __gtod_offset;
+
+struct sched_clock_data {
+	u64			tick_raw;
+	u64			tick_gtod;
+	u64			clock;
+};
+
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct sched_clock_data, sched_clock_data);
+
+notrace static inline struct sched_clock_data *this_scd(void)
+{
+	return this_cpu_ptr(&sched_clock_data);
+}
+
+notrace static inline struct sched_clock_data *cpu_sdc(int cpu)
+{
+	return &per_cpu(sched_clock_data, cpu);
+}
+
+notrace int sched_clock_stable(void)
+{
+	return static_branch_likely(&__sched_clock_stable);
+}
+
+notrace static void __scd_stamp(struct sched_clock_data *scd)
+{
+	scd->tick_gtod = ktime_get_ns();
+	scd->tick_raw = sched_clock();
+}
+
+notrace static void __set_sched_clock_stable(void)
+{
+	struct sched_clock_data *scd;
+
+	/*
+	 * Since we're still unstable and the tick is already running, we have
+	 * to disable IRQs in order to get a consistent scd->tick* reading.
+	 */
+	local_irq_disable();
+	scd = this_scd();
+	/*
+	 * Attempt to make the (initial) unstable->stable transition continuous.
+	 */
+	__sched_clock_offset = (scd->tick_gtod + __gtod_offset) - (scd->tick_raw);
+	local_irq_enable();
+
+	printk(KERN_INFO "sched_clock: Marking stable (%lld, %lld)->(%lld, %lld)\n",
+			scd->tick_gtod, __gtod_offset,
+			scd->tick_raw,  __sched_clock_offset);
+
+	static_branch_enable(&__sched_clock_stable);
+	tick_dep_clear(TICK_DEP_BIT_CLOCK_UNSTABLE);
+}
+
+/*
+ * If we ever get here, we're screwed, because we found out -- typically after
+ * the fact -- that TSC wasn't good. This means all our clocksources (including
+ * ktime) could have reported wrong values.
+ *
+ * What we do here is an attempt to fix up and continue sort of where we left
+ * off in a coherent manner.
+ *
+ * The only way to fully avoid random clock jumps is to boot with:
+ * "tsc=unstable".
+ */
+notrace static void __sched_clock_work(struct work_struct *work)
+{
+	struct sched_clock_data *scd;
+	int cpu;
+
+	/* take a current timestamp and set 'now' */
+	preempt_disable();
+	scd = this_scd();
+	__scd_stamp(scd);
+	scd->clock = scd->tick_gtod + __gtod_offset;
+	preempt_enable();
+
+	/* clone to all CPUs */
+	for_each_possible_cpu(cpu)
+		per_cpu(sched_clock_data, cpu) = *scd;
+
+	printk(KERN_WARNING "TSC found unstable after boot, most likely due to broken BIOS. Use 'tsc=unstable'.\n");
+	printk(KERN_INFO "sched_clock: Marking unstable (%lld, %lld)<-(%lld, %lld)\n",
+			scd->tick_gtod, __gtod_offset,
+			scd->tick_raw,  __sched_clock_offset);
+
+	static_branch_disable(&__sched_clock_stable);
+}
+
+static DECLARE_WORK(sched_clock_work, __sched_clock_work);
+
+notrace static void __clear_sched_clock_stable(void)
+{
+	if (!sched_clock_stable())
+		return;
+
+	tick_dep_set(TICK_DEP_BIT_CLOCK_UNSTABLE);
+	schedule_work(&sched_clock_work);
+}
+
+notrace void clear_sched_clock_stable(void)
+{
+	__sched_clock_stable_early = 0;
+
+	smp_mb(); /* matches sched_clock_init_late() */
+
+	if (static_key_count(&sched_clock_running.key) == 2)
+		__clear_sched_clock_stable();
+}
+
+notrace static void __sched_clock_gtod_offset(void)
+{
+	struct sched_clock_data *scd = this_scd();
+
+	__scd_stamp(scd);
+	__gtod_offset = (scd->tick_raw + __sched_clock_offset) - scd->tick_gtod;
+}
+
+void __init sched_clock_init(void)
+{
+	/*
+	 * Set __gtod_offset such that once we mark sched_clock_running,
+	 * sched_clock_tick() continues where sched_clock() left off.
+	 *
+	 * Even if TSC is buggered, we're still UP at this point so it
+	 * can't really be out of sync.
+	 */
+	local_irq_disable();
+	__sched_clock_gtod_offset();
+	local_irq_enable();
+
+	static_branch_inc(&sched_clock_running);
+}
+/*
+ * We run this as late_initcall() such that it runs after all built-in drivers,
+ * notably: acpi_processor and intel_idle, which can mark the TSC as unstable.
+ */
+static int __init sched_clock_init_late(void)
+{
+	static_branch_inc(&sched_clock_running);
+	/*
+	 * Ensure that it is impossible to not do a static_key update.
+	 *
+	 * Either {set,clear}_sched_clock_stable() must see sched_clock_running
+	 * and do the update, or we must see their __sched_clock_stable_early
+	 * and do the update, or both.
+	 */
+	smp_mb(); /* matches {set,clear}_sched_clock_stable() */
+
+	if (__sched_clock_stable_early)
+		__set_sched_clock_stable();
+
+	return 0;
+}
+late_initcall(sched_clock_init_late);
+
+/*
+ * min, max except they take wrapping into account
+ */
+
+notrace static inline u64 wrap_min(u64 x, u64 y)
+{
+	return (s64)(x - y) < 0 ? x : y;
+}
+
+notrace static inline u64 wrap_max(u64 x, u64 y)
+{
+	return (s64)(x - y) > 0 ? x : y;
+}
+
+/*
+ * update the percpu scd from the raw @now value
+ *
+ *  - filter out backward motion
+ *  - use the GTOD tick value to create a window to filter crazy TSC values
+ */
+notrace static u64 sched_clock_local(struct sched_clock_data *scd)
+{
+	u64 now, clock, old_clock, min_clock, max_clock, gtod;
+	s64 delta;
+
+again:
+	now = sched_clock();
+	delta = now - scd->tick_raw;
+	if (unlikely(delta < 0))
+		delta = 0;
+
+	old_clock = scd->clock;
+
+	/*
+	 * scd->clock = clamp(scd->tick_gtod + delta,
+	 *		      max(scd->tick_gtod, scd->clock),
+	 *		      scd->tick_gtod + TICK_NSEC);
+	 */
+
+	gtod = scd->tick_gtod + __gtod_offset;
+	clock = gtod + delta;
+	min_clock = wrap_max(gtod, old_clock);
+	max_clock = wrap_max(old_clock, gtod + TICK_NSEC);
+
+	clock = wrap_max(clock, min_clock);
+	clock = wrap_min(clock, max_clock);
+
+	if (!try_cmpxchg64(&scd->clock, &old_clock, clock))
+		goto again;
+
+	return clock;
+}
+
+notrace static u64 sched_clock_remote(struct sched_clock_data *scd)
+{
+	struct sched_clock_data *my_scd = this_scd();
+	u64 this_clock, remote_clock;
+	u64 *ptr, old_val, val;
+
+#if BITS_PER_LONG != 64
+again:
+	/*
+	 * Careful here: The local and the remote clock values need to
+	 * be read out atomic as we need to compare the values and
+	 * then update either the local or the remote side. So the
+	 * cmpxchg64 below only protects one readout.
+	 *
+	 * We must reread via sched_clock_local() in the retry case on
+	 * 32-bit kernels as an NMI could use sched_clock_local() via the
+	 * tracer and hit between the readout of
+	 * the low 32-bit and the high 32-bit portion.
+	 */
+	this_clock = sched_clock_local(my_scd);
+	/*
+	 * We must enforce atomic readout on 32-bit, otherwise the
+	 * update on the remote CPU can hit inbetween the readout of
+	 * the low 32-bit and the high 32-bit portion.
+	 */
+	remote_clock = cmpxchg64(&scd->clock, 0, 0);
+#else
+	/*
+	 * On 64-bit kernels the read of [my]scd->clock is atomic versus the
+	 * update, so we can avoid the above 32-bit dance.
+	 */
+	sched_clock_local(my_scd);
+again:
+	this_clock = my_scd->clock;
+	remote_clock = scd->clock;
+#endif
+
+	/*
+	 * Use the opportunity that we have both locks
+	 * taken to couple the two clocks: we take the
+	 * larger time as the latest time for both
+	 * runqueues. (this creates monotonic movement)
+	 */
+	if (likely((s64)(remote_clock - this_clock) < 0)) {
+		ptr = &scd->clock;
+		old_val = remote_clock;
+		val = this_clock;
+	} else {
+		/*
+		 * Should be rare, but possible:
+		 */
+		ptr = &my_scd->clock;
+		old_val = this_clock;
+		val = remote_clock;
+	}
+
+	if (!try_cmpxchg64(ptr, &old_val, val))
+		goto again;
+
+	return val;
+}
+
+/*
+ * Similar to cpu_clock(), but requires local IRQs to be disabled.
+ *
+ * See cpu_clock().
+ */
+notrace u64 sched_clock_cpu(int cpu)
+{
+	struct sched_clock_data *scd;
+	u64 clock;
+
+	if (sched_clock_stable())
+		return sched_clock() + __sched_clock_offset;
+
+	if (!static_branch_likely(&sched_clock_running))
+		return sched_clock();
+
+	preempt_disable_notrace();
+	scd = cpu_sdc(cpu);
+
+	if (cpu != smp_processor_id())
+		clock = sched_clock_remote(scd);
+	else
+		clock = sched_clock_local(scd);
+	preempt_enable_notrace();
+
+	return clock;
+}
+EXPORT_SYMBOL_GPL(sched_clock_cpu);
+
+notrace void sched_clock_tick(void)
+{
+	struct sched_clock_data *scd;
+
+	if (sched_clock_stable())
+		return;
+
+	if (!static_branch_likely(&sched_clock_running))
+		return;
+
+	lockdep_assert_irqs_disabled();
+
+	scd = this_scd();
+	__scd_stamp(scd);
+	sched_clock_local(scd);
+}
+
+notrace void sched_clock_tick_stable(void)
+{
+	if (!sched_clock_stable())
+		return;
+
+	/*
+	 * Called under watchdog_lock.
+	 *
+	 * The watchdog just found this TSC to (still) be stable, so now is a
+	 * good moment to update our __gtod_offset. Because once we find the
+	 * TSC to be unstable, any computation will be computing crap.
+	 */
+	local_irq_disable();
+	__sched_clock_gtod_offset();
+	local_irq_enable();
+}
+
+/*
+ * We are going deep-idle (irqs are disabled):
+ */
+notrace void sched_clock_idle_sleep_event(void)
+{
+	sched_clock_cpu(smp_processor_id());
+}
+EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
+
+/*
+ * We just idled; resync with ktime.
+ */
+notrace void sched_clock_idle_wakeup_event(void)
+{
+	unsigned long flags;
+
+	if (sched_clock_stable())
+		return;
+
+	if (unlikely(timekeeping_suspended))
+		return;
+
+	local_irq_save(flags);
+	sched_clock_tick();
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
+
+#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
+
+void __init sched_clock_init(void)
+{
+	static_branch_inc(&sched_clock_running);
+	local_irq_disable();
+	generic_sched_clock_init();
+	local_irq_enable();
+}
+
+notrace u64 sched_clock_cpu(int cpu)
+{
+	if (!static_branch_likely(&sched_clock_running))
+		return 0;
+
+	return sched_clock();
+}
+
+#endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
+
+/*
+ * Running clock - returns the time that has elapsed while a guest has been
+ * running.
+ * On a guest this value should be local_clock minus the time the guest was
+ * suspended by the hypervisor (for any reason).
+ * On bare metal this function should return the same as local_clock.
+ * Architectures and sub-architectures can override this.
+ */
+notrace u64 __weak running_clock(void)
+{
+	return local_clock();
+}
diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c
new file mode 100644
index 000000000..d57a5c1c1
--- /dev/null
+++ b/kernel/sched/completion.c
@@ -0,0 +1,343 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Generic wait-for-completion handler;
+ *
+ * It differs from semaphores in that their default case is the opposite,
+ * wait_for_completion default blocks whereas semaphore default non-block. The
+ * interface also makes it easy to 'complete' multiple waiting threads,
+ * something which isn't entirely natural for semaphores.
+ *
+ * But more importantly, the primitive documents the usage. Semaphores would
+ * typically be used for exclusion which gives rise to priority inversion.
+ * Waiting for completion is a typically sync point, but not an exclusion point.
+ */
+
+/**
+ * complete: - signals a single thread waiting on this completion
+ * @x:  holds the state of this particular completion
+ *
+ * This will wake up a single thread waiting on this completion. Threads will be
+ * awakened in the same order in which they were queued.
+ *
+ * See also complete_all(), wait_for_completion() and related routines.
+ *
+ * If this function wakes up a task, it executes a full memory barrier before
+ * accessing the task state.
+ */
+void complete(struct completion *x)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
+
+	if (x->done != UINT_MAX)
+		x->done++;
+	swake_up_locked(&x->wait);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
+}
+EXPORT_SYMBOL(complete);
+
+/**
+ * complete_all: - signals all threads waiting on this completion
+ * @x:  holds the state of this particular completion
+ *
+ * This will wake up all threads waiting on this particular completion event.
+ *
+ * If this function wakes up a task, it executes a full memory barrier before
+ * accessing the task state.
+ *
+ * Since complete_all() sets the completion of @x permanently to done
+ * to allow multiple waiters to finish, a call to reinit_completion()
+ * must be used on @x if @x is to be used again. The code must make
+ * sure that all waiters have woken and finished before reinitializing
+ * @x. Also note that the function completion_done() can not be used
+ * to know if there are still waiters after complete_all() has been called.
+ */
+void complete_all(struct completion *x)
+{
+	unsigned long flags;
+
+	lockdep_assert_RT_in_threaded_ctx();
+
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
+	x->done = UINT_MAX;
+	swake_up_all_locked(&x->wait);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
+}
+EXPORT_SYMBOL(complete_all);
+
+static inline long __sched
+do_wait_for_common(struct completion *x,
+		   long (*action)(long), long timeout, int state)
+{
+	if (!x->done) {
+		DECLARE_SWAITQUEUE(wait);
+
+		do {
+			if (signal_pending_state(state, current)) {
+				timeout = -ERESTARTSYS;
+				break;
+			}
+			__prepare_to_swait(&x->wait, &wait);
+			__set_current_state(state);
+			raw_spin_unlock_irq(&x->wait.lock);
+			timeout = action(timeout);
+			raw_spin_lock_irq(&x->wait.lock);
+		} while (!x->done && timeout);
+		__finish_swait(&x->wait, &wait);
+		if (!x->done)
+			return timeout;
+	}
+	if (x->done != UINT_MAX)
+		x->done--;
+	return timeout ?: 1;
+}
+
+static inline long __sched
+__wait_for_common(struct completion *x,
+		  long (*action)(long), long timeout, int state)
+{
+	might_sleep();
+
+	complete_acquire(x);
+
+	raw_spin_lock_irq(&x->wait.lock);
+	timeout = do_wait_for_common(x, action, timeout, state);
+	raw_spin_unlock_irq(&x->wait.lock);
+
+	complete_release(x);
+
+	return timeout;
+}
+
+static long __sched
+wait_for_common(struct completion *x, long timeout, int state)
+{
+	return __wait_for_common(x, schedule_timeout, timeout, state);
+}
+
+static long __sched
+wait_for_common_io(struct completion *x, long timeout, int state)
+{
+	return __wait_for_common(x, io_schedule_timeout, timeout, state);
+}
+
+/**
+ * wait_for_completion: - waits for completion of a task
+ * @x:  holds the state of this particular completion
+ *
+ * This waits to be signaled for completion of a specific task. It is NOT
+ * interruptible and there is no timeout.
+ *
+ * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
+ * and interrupt capability. Also see complete().
+ */
+void __sched wait_for_completion(struct completion *x)
+{
+	wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion);
+
+/**
+ * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
+ * @x:  holds the state of this particular completion
+ * @timeout:  timeout value in jiffies
+ *
+ * This waits for either a completion of a specific task to be signaled or for a
+ * specified timeout to expire. The timeout is in jiffies. It is not
+ * interruptible.
+ *
+ * Return: 0 if timed out, and positive (at least 1, or number of jiffies left
+ * till timeout) if completed.
+ */
+unsigned long __sched
+wait_for_completion_timeout(struct completion *x, unsigned long timeout)
+{
+	return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion_timeout);
+
+/**
+ * wait_for_completion_io: - waits for completion of a task
+ * @x:  holds the state of this particular completion
+ *
+ * This waits to be signaled for completion of a specific task. It is NOT
+ * interruptible and there is no timeout. The caller is accounted as waiting
+ * for IO (which traditionally means blkio only).
+ */
+void __sched wait_for_completion_io(struct completion *x)
+{
+	wait_for_common_io(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion_io);
+
+/**
+ * wait_for_completion_io_timeout: - waits for completion of a task (w/timeout)
+ * @x:  holds the state of this particular completion
+ * @timeout:  timeout value in jiffies
+ *
+ * This waits for either a completion of a specific task to be signaled or for a
+ * specified timeout to expire. The timeout is in jiffies. It is not
+ * interruptible. The caller is accounted as waiting for IO (which traditionally
+ * means blkio only).
+ *
+ * Return: 0 if timed out, and positive (at least 1, or number of jiffies left
+ * till timeout) if completed.
+ */
+unsigned long __sched
+wait_for_completion_io_timeout(struct completion *x, unsigned long timeout)
+{
+	return wait_for_common_io(x, timeout, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion_io_timeout);
+
+/**
+ * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
+ * @x:  holds the state of this particular completion
+ *
+ * This waits for completion of a specific task to be signaled. It is
+ * interruptible.
+ *
+ * Return: -ERESTARTSYS if interrupted, 0 if completed.
+ */
+int __sched wait_for_completion_interruptible(struct completion *x)
+{
+	long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
+
+	if (t == -ERESTARTSYS)
+		return t;
+	return 0;
+}
+EXPORT_SYMBOL(wait_for_completion_interruptible);
+
+/**
+ * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
+ * @x:  holds the state of this particular completion
+ * @timeout:  timeout value in jiffies
+ *
+ * This waits for either a completion of a specific task to be signaled or for a
+ * specified timeout to expire. It is interruptible. The timeout is in jiffies.
+ *
+ * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1,
+ * or number of jiffies left till timeout) if completed.
+ */
+long __sched
+wait_for_completion_interruptible_timeout(struct completion *x,
+					  unsigned long timeout)
+{
+	return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
+
+/**
+ * wait_for_completion_killable: - waits for completion of a task (killable)
+ * @x:  holds the state of this particular completion
+ *
+ * This waits to be signaled for completion of a specific task. It can be
+ * interrupted by a kill signal.
+ *
+ * Return: -ERESTARTSYS if interrupted, 0 if completed.
+ */
+int __sched wait_for_completion_killable(struct completion *x)
+{
+	long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
+
+	if (t == -ERESTARTSYS)
+		return t;
+	return 0;
+}
+EXPORT_SYMBOL(wait_for_completion_killable);
+
+int __sched wait_for_completion_state(struct completion *x, unsigned int state)
+{
+	long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, state);
+
+	if (t == -ERESTARTSYS)
+		return t;
+	return 0;
+}
+EXPORT_SYMBOL(wait_for_completion_state);
+
+/**
+ * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
+ * @x:  holds the state of this particular completion
+ * @timeout:  timeout value in jiffies
+ *
+ * This waits for either a completion of a specific task to be
+ * signaled or for a specified timeout to expire. It can be
+ * interrupted by a kill signal. The timeout is in jiffies.
+ *
+ * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1,
+ * or number of jiffies left till timeout) if completed.
+ */
+long __sched
+wait_for_completion_killable_timeout(struct completion *x,
+				     unsigned long timeout)
+{
+	return wait_for_common(x, timeout, TASK_KILLABLE);
+}
+EXPORT_SYMBOL(wait_for_completion_killable_timeout);
+
+/**
+ *	try_wait_for_completion - try to decrement a completion without blocking
+ *	@x:	completion structure
+ *
+ *	Return: 0 if a decrement cannot be done without blocking
+ *		 1 if a decrement succeeded.
+ *
+ *	If a completion is being used as a counting completion,
+ *	attempt to decrement the counter without blocking. This
+ *	enables us to avoid waiting if the resource the completion
+ *	is protecting is not available.
+ */
+bool try_wait_for_completion(struct completion *x)
+{
+	unsigned long flags;
+	bool ret = true;
+
+	/*
+	 * Since x->done will need to be locked only
+	 * in the non-blocking case, we check x->done
+	 * first without taking the lock so we can
+	 * return early in the blocking case.
+	 */
+	if (!READ_ONCE(x->done))
+		return false;
+
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
+	if (!x->done)
+		ret = false;
+	else if (x->done != UINT_MAX)
+		x->done--;
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL(try_wait_for_completion);
+
+/**
+ *	completion_done - Test to see if a completion has any waiters
+ *	@x:	completion structure
+ *
+ *	Return: 0 if there are waiters (wait_for_completion() in progress)
+ *		 1 if there are no waiters.
+ *
+ *	Note, this will always return true if complete_all() was called on @X.
+ */
+bool completion_done(struct completion *x)
+{
+	unsigned long flags;
+
+	if (!READ_ONCE(x->done))
+		return false;
+
+	/*
+	 * If ->done, we need to wait for complete() to release ->wait.lock
+	 * otherwise we can end up freeing the completion before complete()
+	 * is done referencing it.
+	 */
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
+	return true;
+}
+EXPORT_SYMBOL(completion_done);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
new file mode 100644
index 000000000..18a4f8f28
--- /dev/null
+++ b/kernel/sched/core.c
@@ -0,0 +1,11264 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  kernel/sched/core.c
+ *
+ *  Core kernel scheduler code and related syscalls
+ *
+ *  Copyright (C) 1991-2002  Linus Torvalds
+ */
+#include <linux/highmem.h>
+#include <linux/hrtimer_api.h>
+#include <linux/ktime_api.h>
+#include <linux/sched/signal.h>
+#include <linux/syscalls_api.h>
+#include <linux/debug_locks.h>
+#include <linux/prefetch.h>
+#include <linux/capability.h>
+#include <linux/pgtable_api.h>
+#include <linux/wait_bit.h>
+#include <linux/jiffies.h>
+#include <linux/spinlock_api.h>
+#include <linux/cpumask_api.h>
+#include <linux/lockdep_api.h>
+#include <linux/hardirq.h>
+#include <linux/softirq.h>
+#include <linux/refcount_api.h>
+#include <linux/topology.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/cond_resched.h>
+#include <linux/sched/cputime.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/hotplug.h>
+#include <linux/sched/init.h>
+#include <linux/sched/isolation.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/nohz.h>
+#include <linux/sched/rseq_api.h>
+#include <linux/sched/rt.h>
+
+#include <linux/blkdev.h>
+#include <linux/context_tracking.h>
+#include <linux/cpuset.h>
+#include <linux/delayacct.h>
+#include <linux/init_task.h>
+#include <linux/interrupt.h>
+#include <linux/ioprio.h>
+#include <linux/kallsyms.h>
+#include <linux/kcov.h>
+#include <linux/kprobes.h>
+#include <linux/llist_api.h>
+#include <linux/mmu_context.h>
+#include <linux/mmzone.h>
+#include <linux/mutex_api.h>
+#include <linux/nmi.h>
+#include <linux/nospec.h>
+#include <linux/perf_event_api.h>
+#include <linux/profile.h>
+#include <linux/psi.h>
+#include <linux/rcuwait_api.h>
+#include <linux/sched/wake_q.h>
+#include <linux/scs.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/vtime.h>
+#include <linux/wait_api.h>
+#include <linux/workqueue_api.h>
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+# ifdef CONFIG_GENERIC_ENTRY
+#  include <linux/entry-common.h>
+# endif
+#endif
+
+#include <uapi/linux/sched/types.h>
+
+#include <asm/irq_regs.h>
+#include <asm/switch_to.h>
+#include <asm/tlb.h>
+
+#define CREATE_TRACE_POINTS
+#include <linux/sched/rseq_api.h>
+#include <trace/events/sched.h>
+#undef CREATE_TRACE_POINTS
+
+#include "sched.h"
+#include "stats.h"
+#include "autogroup.h"
+
+#include "autogroup.h"
+#include "pelt.h"
+#include "smp.h"
+#include "stats.h"
+
+#include "../workqueue_internal.h"
+#include "../../io_uring/io-wq.h"
+#include "../smpboot.h"
+
+/*
+ * Export tracepoints that act as a bare tracehook (ie: have no trace event
+ * associated with them) to allow external modules to probe them.
+ */
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_cfs_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_rt_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_dl_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_irq_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_se_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_thermal_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_cpu_capacity_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_overutilized_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_util_est_cfs_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_util_est_se_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_update_nr_running_tp);
+
+DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
+
+#ifdef CONFIG_SCHED_DEBUG
+/*
+ * Debugging: various feature bits
+ *
+ * If SCHED_DEBUG is disabled, each compilation unit has its own copy of
+ * sysctl_sched_features, defined in sched.h, to allow constants propagation
+ * at compile time and compiler optimization based on features default.
+ */
+#define SCHED_FEAT(name, enabled)	\
+	(1UL << __SCHED_FEAT_##name) * enabled |
+const_debug unsigned int sysctl_sched_features =
+#include "features.h"
+	0;
+#undef SCHED_FEAT
+
+/*
+ * Print a warning if need_resched is set for the given duration (if
+ * LATENCY_WARN is enabled).
+ *
+ * If sysctl_resched_latency_warn_once is set, only one warning will be shown
+ * per boot.
+ */
+__read_mostly int sysctl_resched_latency_warn_ms = 100;
+__read_mostly int sysctl_resched_latency_warn_once = 1;
+#endif /* CONFIG_SCHED_DEBUG */
+
+/*
+ * Number of tasks to iterate in a single balance run.
+ * Limited because this is done with IRQs disabled.
+ */
+const_debug unsigned int sysctl_sched_nr_migrate = SCHED_NR_MIGRATE_BREAK;
+
+__read_mostly int scheduler_running;
+
+#ifdef CONFIG_SCHED_CORE
+
+DEFINE_STATIC_KEY_FALSE(__sched_core_enabled);
+
+/* kernel prio, less is more */
+static inline int __task_prio(struct task_struct *p)
+{
+	if (p->sched_class == &stop_sched_class) /* trumps deadline */
+		return -2;
+
+	if (rt_prio(p->prio)) /* includes deadline */
+		return p->prio; /* [-1, 99] */
+
+	if (p->sched_class == &idle_sched_class)
+		return MAX_RT_PRIO + NICE_WIDTH; /* 140 */
+
+	return MAX_RT_PRIO + MAX_NICE; /* 120, squash fair */
+}
+
+/*
+ * l(a,b)
+ * le(a,b) := !l(b,a)
+ * g(a,b)  := l(b,a)
+ * ge(a,b) := !l(a,b)
+ */
+
+/* real prio, less is less */
+static inline bool prio_less(struct task_struct *a, struct task_struct *b, bool in_fi)
+{
+
+	int pa = __task_prio(a), pb = __task_prio(b);
+
+	if (-pa < -pb)
+		return true;
+
+	if (-pb < -pa)
+		return false;
+
+	if (pa == -1) /* dl_prio() doesn't work because of stop_class above */
+		return !dl_time_before(a->dl.deadline, b->dl.deadline);
+
+	if (pa == MAX_RT_PRIO + MAX_NICE)	/* fair */
+		return cfs_prio_less(a, b, in_fi);
+
+	return false;
+}
+
+static inline bool __sched_core_less(struct task_struct *a, struct task_struct *b)
+{
+	if (a->core_cookie < b->core_cookie)
+		return true;
+
+	if (a->core_cookie > b->core_cookie)
+		return false;
+
+	/* flip prio, so high prio is leftmost */
+	if (prio_less(b, a, !!task_rq(a)->core->core_forceidle_count))
+		return true;
+
+	return false;
+}
+
+#define __node_2_sc(node) rb_entry((node), struct task_struct, core_node)
+
+static inline bool rb_sched_core_less(struct rb_node *a, const struct rb_node *b)
+{
+	return __sched_core_less(__node_2_sc(a), __node_2_sc(b));
+}
+
+static inline int rb_sched_core_cmp(const void *key, const struct rb_node *node)
+{
+	const struct task_struct *p = __node_2_sc(node);
+	unsigned long cookie = (unsigned long)key;
+
+	if (cookie < p->core_cookie)
+		return -1;
+
+	if (cookie > p->core_cookie)
+		return 1;
+
+	return 0;
+}
+
+void sched_core_enqueue(struct rq *rq, struct task_struct *p)
+{
+	rq->core->core_task_seq++;
+
+	if (!p->core_cookie)
+		return;
+
+	rb_add(&p->core_node, &rq->core_tree, rb_sched_core_less);
+}
+
+void sched_core_dequeue(struct rq *rq, struct task_struct *p, int flags)
+{
+	rq->core->core_task_seq++;
+
+	if (sched_core_enqueued(p)) {
+		rb_erase(&p->core_node, &rq->core_tree);
+		RB_CLEAR_NODE(&p->core_node);
+	}
+
+	/*
+	 * Migrating the last task off the cpu, with the cpu in forced idle
+	 * state. Reschedule to create an accounting edge for forced idle,
+	 * and re-examine whether the core is still in forced idle state.
+	 */
+	if (!(flags & DEQUEUE_SAVE) && rq->nr_running == 1 &&
+	    rq->core->core_forceidle_count && rq->curr == rq->idle)
+		resched_curr(rq);
+}
+
+/*
+ * Find left-most (aka, highest priority) task matching @cookie.
+ */
+static struct task_struct *sched_core_find(struct rq *rq, unsigned long cookie)
+{
+	struct rb_node *node;
+
+	node = rb_find_first((void *)cookie, &rq->core_tree, rb_sched_core_cmp);
+	/*
+	 * The idle task always matches any cookie!
+	 */
+	if (!node)
+		return idle_sched_class.pick_task(rq);
+
+	return __node_2_sc(node);
+}
+
+static struct task_struct *sched_core_next(struct task_struct *p, unsigned long cookie)
+{
+	struct rb_node *node = &p->core_node;
+
+	node = rb_next(node);
+	if (!node)
+		return NULL;
+
+	p = container_of(node, struct task_struct, core_node);
+	if (p->core_cookie != cookie)
+		return NULL;
+
+	return p;
+}
+
+/*
+ * Magic required such that:
+ *
+ *	raw_spin_rq_lock(rq);
+ *	...
+ *	raw_spin_rq_unlock(rq);
+ *
+ * ends up locking and unlocking the _same_ lock, and all CPUs
+ * always agree on what rq has what lock.
+ *
+ * XXX entirely possible to selectively enable cores, don't bother for now.
+ */
+
+static DEFINE_MUTEX(sched_core_mutex);
+static atomic_t sched_core_count;
+static struct cpumask sched_core_mask;
+
+static void sched_core_lock(int cpu, unsigned long *flags)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+	int t, i = 0;
+
+	local_irq_save(*flags);
+	for_each_cpu(t, smt_mask)
+		raw_spin_lock_nested(&cpu_rq(t)->__lock, i++);
+}
+
+static void sched_core_unlock(int cpu, unsigned long *flags)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+	int t;
+
+	for_each_cpu(t, smt_mask)
+		raw_spin_unlock(&cpu_rq(t)->__lock);
+	local_irq_restore(*flags);
+}
+
+static void __sched_core_flip(bool enabled)
+{
+	unsigned long flags;
+	int cpu, t;
+
+	cpus_read_lock();
+
+	/*
+	 * Toggle the online cores, one by one.
+	 */
+	cpumask_copy(&sched_core_mask, cpu_online_mask);
+	for_each_cpu(cpu, &sched_core_mask) {
+		const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+
+		sched_core_lock(cpu, &flags);
+
+		for_each_cpu(t, smt_mask)
+			cpu_rq(t)->core_enabled = enabled;
+
+		cpu_rq(cpu)->core->core_forceidle_start = 0;
+
+		sched_core_unlock(cpu, &flags);
+
+		cpumask_andnot(&sched_core_mask, &sched_core_mask, smt_mask);
+	}
+
+	/*
+	 * Toggle the offline CPUs.
+	 */
+	for_each_cpu_andnot(cpu, cpu_possible_mask, cpu_online_mask)
+		cpu_rq(cpu)->core_enabled = enabled;
+
+	cpus_read_unlock();
+}
+
+static void sched_core_assert_empty(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		WARN_ON_ONCE(!RB_EMPTY_ROOT(&cpu_rq(cpu)->core_tree));
+}
+
+static void __sched_core_enable(void)
+{
+	static_branch_enable(&__sched_core_enabled);
+	/*
+	 * Ensure all previous instances of raw_spin_rq_*lock() have finished
+	 * and future ones will observe !sched_core_disabled().
+	 */
+	synchronize_rcu();
+	__sched_core_flip(true);
+	sched_core_assert_empty();
+}
+
+static void __sched_core_disable(void)
+{
+	sched_core_assert_empty();
+	__sched_core_flip(false);
+	static_branch_disable(&__sched_core_enabled);
+}
+
+void sched_core_get(void)
+{
+	if (atomic_inc_not_zero(&sched_core_count))
+		return;
+
+	mutex_lock(&sched_core_mutex);
+	if (!atomic_read(&sched_core_count))
+		__sched_core_enable();
+
+	smp_mb__before_atomic();
+	atomic_inc(&sched_core_count);
+	mutex_unlock(&sched_core_mutex);
+}
+
+static void __sched_core_put(struct work_struct *work)
+{
+	if (atomic_dec_and_mutex_lock(&sched_core_count, &sched_core_mutex)) {
+		__sched_core_disable();
+		mutex_unlock(&sched_core_mutex);
+	}
+}
+
+void sched_core_put(void)
+{
+	static DECLARE_WORK(_work, __sched_core_put);
+
+	/*
+	 * "There can be only one"
+	 *
+	 * Either this is the last one, or we don't actually need to do any
+	 * 'work'. If it is the last *again*, we rely on
+	 * WORK_STRUCT_PENDING_BIT.
+	 */
+	if (!atomic_add_unless(&sched_core_count, -1, 1))
+		schedule_work(&_work);
+}
+
+#else /* !CONFIG_SCHED_CORE */
+
+static inline void sched_core_enqueue(struct rq *rq, struct task_struct *p) { }
+static inline void
+sched_core_dequeue(struct rq *rq, struct task_struct *p, int flags) { }
+
+#endif /* CONFIG_SCHED_CORE */
+
+/*
+ * Serialization rules:
+ *
+ * Lock order:
+ *
+ *   p->pi_lock
+ *     rq->lock
+ *       hrtimer_cpu_base->lock (hrtimer_start() for bandwidth controls)
+ *
+ *  rq1->lock
+ *    rq2->lock  where: rq1 < rq2
+ *
+ * Regular state:
+ *
+ * Normal scheduling state is serialized by rq->lock. __schedule() takes the
+ * local CPU's rq->lock, it optionally removes the task from the runqueue and
+ * always looks at the local rq data structures to find the most eligible task
+ * to run next.
+ *
+ * Task enqueue is also under rq->lock, possibly taken from another CPU.
+ * Wakeups from another LLC domain might use an IPI to transfer the enqueue to
+ * the local CPU to avoid bouncing the runqueue state around [ see
+ * ttwu_queue_wakelist() ]
+ *
+ * Task wakeup, specifically wakeups that involve migration, are horribly
+ * complicated to avoid having to take two rq->locks.
+ *
+ * Special state:
+ *
+ * System-calls and anything external will use task_rq_lock() which acquires
+ * both p->pi_lock and rq->lock. As a consequence the state they change is
+ * stable while holding either lock:
+ *
+ *  - sched_setaffinity()/
+ *    set_cpus_allowed_ptr():	p->cpus_ptr, p->nr_cpus_allowed
+ *  - set_user_nice():		p->se.load, p->*prio
+ *  - __sched_setscheduler():	p->sched_class, p->policy, p->*prio,
+ *				p->se.load, p->rt_priority,
+ *				p->dl.dl_{runtime, deadline, period, flags, bw, density}
+ *  - sched_setnuma():		p->numa_preferred_nid
+ *  - sched_move_task():	p->sched_task_group
+ *  - uclamp_update_active()	p->uclamp*
+ *
+ * p->state <- TASK_*:
+ *
+ *   is changed locklessly using set_current_state(), __set_current_state() or
+ *   set_special_state(), see their respective comments, or by
+ *   try_to_wake_up(). This latter uses p->pi_lock to serialize against
+ *   concurrent self.
+ *
+ * p->on_rq <- { 0, 1 = TASK_ON_RQ_QUEUED, 2 = TASK_ON_RQ_MIGRATING }:
+ *
+ *   is set by activate_task() and cleared by deactivate_task(), under
+ *   rq->lock. Non-zero indicates the task is runnable, the special
+ *   ON_RQ_MIGRATING state is used for migration without holding both
+ *   rq->locks. It indicates task_cpu() is not stable, see task_rq_lock().
+ *
+ * p->on_cpu <- { 0, 1 }:
+ *
+ *   is set by prepare_task() and cleared by finish_task() such that it will be
+ *   set before p is scheduled-in and cleared after p is scheduled-out, both
+ *   under rq->lock. Non-zero indicates the task is running on its CPU.
+ *
+ *   [ The astute reader will observe that it is possible for two tasks on one
+ *     CPU to have ->on_cpu = 1 at the same time. ]
+ *
+ * task_cpu(p): is changed by set_task_cpu(), the rules are:
+ *
+ *  - Don't call set_task_cpu() on a blocked task:
+ *
+ *    We don't care what CPU we're not running on, this simplifies hotplug,
+ *    the CPU assignment of blocked tasks isn't required to be valid.
+ *
+ *  - for try_to_wake_up(), called under p->pi_lock:
+ *
+ *    This allows try_to_wake_up() to only take one rq->lock, see its comment.
+ *
+ *  - for migration called under rq->lock:
+ *    [ see task_on_rq_migrating() in task_rq_lock() ]
+ *
+ *    o move_queued_task()
+ *    o detach_task()
+ *
+ *  - for migration called under double_rq_lock():
+ *
+ *    o __migrate_swap_task()
+ *    o push_rt_task() / pull_rt_task()
+ *    o push_dl_task() / pull_dl_task()
+ *    o dl_task_offline_migration()
+ *
+ */
+
+void raw_spin_rq_lock_nested(struct rq *rq, int subclass)
+{
+	raw_spinlock_t *lock;
+
+	/* Matches synchronize_rcu() in __sched_core_enable() */
+	preempt_disable();
+	if (sched_core_disabled()) {
+		raw_spin_lock_nested(&rq->__lock, subclass);
+		/* preempt_count *MUST* be > 1 */
+		preempt_enable_no_resched();
+		return;
+	}
+
+	for (;;) {
+		lock = __rq_lockp(rq);
+		raw_spin_lock_nested(lock, subclass);
+		if (likely(lock == __rq_lockp(rq))) {
+			/* preempt_count *MUST* be > 1 */
+			preempt_enable_no_resched();
+			return;
+		}
+		raw_spin_unlock(lock);
+	}
+}
+
+bool raw_spin_rq_trylock(struct rq *rq)
+{
+	raw_spinlock_t *lock;
+	bool ret;
+
+	/* Matches synchronize_rcu() in __sched_core_enable() */
+	preempt_disable();
+	if (sched_core_disabled()) {
+		ret = raw_spin_trylock(&rq->__lock);
+		preempt_enable();
+		return ret;
+	}
+
+	for (;;) {
+		lock = __rq_lockp(rq);
+		ret = raw_spin_trylock(lock);
+		if (!ret || (likely(lock == __rq_lockp(rq)))) {
+			preempt_enable();
+			return ret;
+		}
+		raw_spin_unlock(lock);
+	}
+}
+
+void raw_spin_rq_unlock(struct rq *rq)
+{
+	raw_spin_unlock(rq_lockp(rq));
+}
+
+#ifdef CONFIG_SMP
+/*
+ * double_rq_lock - safely lock two runqueues
+ */
+void double_rq_lock(struct rq *rq1, struct rq *rq2)
+{
+	lockdep_assert_irqs_disabled();
+
+	if (rq_order_less(rq2, rq1))
+		swap(rq1, rq2);
+
+	raw_spin_rq_lock(rq1);
+	if (__rq_lockp(rq1) != __rq_lockp(rq2))
+		raw_spin_rq_lock_nested(rq2, SINGLE_DEPTH_NESTING);
+
+	double_rq_clock_clear_update(rq1, rq2);
+}
+#endif
+
+/*
+ * __task_rq_lock - lock the rq @p resides on.
+ */
+struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	struct rq *rq;
+
+	lockdep_assert_held(&p->pi_lock);
+
+	for (;;) {
+		rq = task_rq(p);
+		raw_spin_rq_lock(rq);
+		if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
+			rq_pin_lock(rq, rf);
+			return rq;
+		}
+		raw_spin_rq_unlock(rq);
+
+		while (unlikely(task_on_rq_migrating(p)))
+			cpu_relax();
+	}
+}
+
+/*
+ * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
+ */
+struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
+	__acquires(p->pi_lock)
+	__acquires(rq->lock)
+{
+	struct rq *rq;
+
+	for (;;) {
+		raw_spin_lock_irqsave(&p->pi_lock, rf->flags);
+		rq = task_rq(p);
+		raw_spin_rq_lock(rq);
+		/*
+		 *	move_queued_task()		task_rq_lock()
+		 *
+		 *	ACQUIRE (rq->lock)
+		 *	[S] ->on_rq = MIGRATING		[L] rq = task_rq()
+		 *	WMB (__set_task_cpu())		ACQUIRE (rq->lock);
+		 *	[S] ->cpu = new_cpu		[L] task_rq()
+		 *					[L] ->on_rq
+		 *	RELEASE (rq->lock)
+		 *
+		 * If we observe the old CPU in task_rq_lock(), the acquire of
+		 * the old rq->lock will fully serialize against the stores.
+		 *
+		 * If we observe the new CPU in task_rq_lock(), the address
+		 * dependency headed by '[L] rq = task_rq()' and the acquire
+		 * will pair with the WMB to ensure we then also see migrating.
+		 */
+		if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
+			rq_pin_lock(rq, rf);
+			return rq;
+		}
+		raw_spin_rq_unlock(rq);
+		raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
+
+		while (unlikely(task_on_rq_migrating(p)))
+			cpu_relax();
+	}
+}
+
+/*
+ * RQ-clock updating methods:
+ */
+
+static void update_rq_clock_task(struct rq *rq, s64 delta)
+{
+/*
+ * In theory, the compile should just see 0 here, and optimize out the call
+ * to sched_rt_avg_update. But I don't trust it...
+ */
+	s64 __maybe_unused steal = 0, irq_delta = 0;
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
+
+	/*
+	 * Since irq_time is only updated on {soft,}irq_exit, we might run into
+	 * this case when a previous update_rq_clock() happened inside a
+	 * {soft,}irq region.
+	 *
+	 * When this happens, we stop ->clock_task and only update the
+	 * prev_irq_time stamp to account for the part that fit, so that a next
+	 * update will consume the rest. This ensures ->clock_task is
+	 * monotonic.
+	 *
+	 * It does however cause some slight miss-attribution of {soft,}irq
+	 * time, a more accurate solution would be to update the irq_time using
+	 * the current rq->clock timestamp, except that would require using
+	 * atomic ops.
+	 */
+	if (irq_delta > delta)
+		irq_delta = delta;
+
+	rq->prev_irq_time += irq_delta;
+	delta -= irq_delta;
+	psi_account_irqtime(rq->curr, irq_delta);
+#endif
+#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
+	if (static_key_false((&paravirt_steal_rq_enabled))) {
+		steal = paravirt_steal_clock(cpu_of(rq));
+		steal -= rq->prev_steal_time_rq;
+
+		if (unlikely(steal > delta))
+			steal = delta;
+
+		rq->prev_steal_time_rq += steal;
+		delta -= steal;
+	}
+#endif
+
+	rq->clock_task += delta;
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+	if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY))
+		update_irq_load_avg(rq, irq_delta + steal);
+#endif
+	update_rq_clock_pelt(rq, delta);
+}
+
+void update_rq_clock(struct rq *rq)
+{
+	s64 delta;
+
+	lockdep_assert_rq_held(rq);
+
+	if (rq->clock_update_flags & RQCF_ACT_SKIP)
+		return;
+
+#ifdef CONFIG_SCHED_DEBUG
+	if (sched_feat(WARN_DOUBLE_CLOCK))
+		SCHED_WARN_ON(rq->clock_update_flags & RQCF_UPDATED);
+	rq->clock_update_flags |= RQCF_UPDATED;
+#endif
+
+	delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
+	if (delta < 0)
+		return;
+	rq->clock += delta;
+	update_rq_clock_task(rq, delta);
+}
+
+#ifdef CONFIG_SCHED_HRTICK
+/*
+ * Use HR-timers to deliver accurate preemption points.
+ */
+
+static void hrtick_clear(struct rq *rq)
+{
+	if (hrtimer_active(&rq->hrtick_timer))
+		hrtimer_cancel(&rq->hrtick_timer);
+}
+
+/*
+ * High-resolution timer tick.
+ * Runs from hardirq context with interrupts disabled.
+ */
+static enum hrtimer_restart hrtick(struct hrtimer *timer)
+{
+	struct rq *rq = container_of(timer, struct rq, hrtick_timer);
+	struct rq_flags rf;
+
+	WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
+
+	rq_lock(rq, &rf);
+	update_rq_clock(rq);
+	rq->curr->sched_class->task_tick(rq, rq->curr, 1);
+	rq_unlock(rq, &rf);
+
+	return HRTIMER_NORESTART;
+}
+
+#ifdef CONFIG_SMP
+
+static void __hrtick_restart(struct rq *rq)
+{
+	struct hrtimer *timer = &rq->hrtick_timer;
+	ktime_t time = rq->hrtick_time;
+
+	hrtimer_start(timer, time, HRTIMER_MODE_ABS_PINNED_HARD);
+}
+
+/*
+ * called from hardirq (IPI) context
+ */
+static void __hrtick_start(void *arg)
+{
+	struct rq *rq = arg;
+	struct rq_flags rf;
+
+	rq_lock(rq, &rf);
+	__hrtick_restart(rq);
+	rq_unlock(rq, &rf);
+}
+
+/*
+ * Called to set the hrtick timer state.
+ *
+ * called with rq->lock held and irqs disabled
+ */
+void hrtick_start(struct rq *rq, u64 delay)
+{
+	struct hrtimer *timer = &rq->hrtick_timer;
+	s64 delta;
+
+	/*
+	 * Don't schedule slices shorter than 10000ns, that just
+	 * doesn't make sense and can cause timer DoS.
+	 */
+	delta = max_t(s64, delay, 10000LL);
+	rq->hrtick_time = ktime_add_ns(timer->base->get_time(), delta);
+
+	if (rq == this_rq())
+		__hrtick_restart(rq);
+	else
+		smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd);
+}
+
+#else
+/*
+ * Called to set the hrtick timer state.
+ *
+ * called with rq->lock held and irqs disabled
+ */
+void hrtick_start(struct rq *rq, u64 delay)
+{
+	/*
+	 * Don't schedule slices shorter than 10000ns, that just
+	 * doesn't make sense. Rely on vruntime for fairness.
+	 */
+	delay = max_t(u64, delay, 10000LL);
+	hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay),
+		      HRTIMER_MODE_REL_PINNED_HARD);
+}
+
+#endif /* CONFIG_SMP */
+
+static void hrtick_rq_init(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+	INIT_CSD(&rq->hrtick_csd, __hrtick_start, rq);
+#endif
+	hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	rq->hrtick_timer.function = hrtick;
+}
+#else	/* CONFIG_SCHED_HRTICK */
+static inline void hrtick_clear(struct rq *rq)
+{
+}
+
+static inline void hrtick_rq_init(struct rq *rq)
+{
+}
+#endif	/* CONFIG_SCHED_HRTICK */
+
+/*
+ * cmpxchg based fetch_or, macro so it works for different integer types
+ */
+#define fetch_or(ptr, mask)						\
+	({								\
+		typeof(ptr) _ptr = (ptr);				\
+		typeof(mask) _mask = (mask);				\
+		typeof(*_ptr) _val = *_ptr;				\
+									\
+		do {							\
+		} while (!try_cmpxchg(_ptr, &_val, _val | _mask));	\
+	_val;								\
+})
+
+#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
+/*
+ * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
+ * this avoids any races wrt polling state changes and thereby avoids
+ * spurious IPIs.
+ */
+static inline bool set_nr_and_not_polling(struct task_struct *p)
+{
+	struct thread_info *ti = task_thread_info(p);
+	return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG);
+}
+
+/*
+ * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
+ *
+ * If this returns true, then the idle task promises to call
+ * sched_ttwu_pending() and reschedule soon.
+ */
+static bool set_nr_if_polling(struct task_struct *p)
+{
+	struct thread_info *ti = task_thread_info(p);
+	typeof(ti->flags) val = READ_ONCE(ti->flags);
+
+	for (;;) {
+		if (!(val & _TIF_POLLING_NRFLAG))
+			return false;
+		if (val & _TIF_NEED_RESCHED)
+			return true;
+		if (try_cmpxchg(&ti->flags, &val, val | _TIF_NEED_RESCHED))
+			break;
+	}
+	return true;
+}
+
+#else
+static inline bool set_nr_and_not_polling(struct task_struct *p)
+{
+	set_tsk_need_resched(p);
+	return true;
+}
+
+#ifdef CONFIG_SMP
+static inline bool set_nr_if_polling(struct task_struct *p)
+{
+	return false;
+}
+#endif
+#endif
+
+static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
+{
+	struct wake_q_node *node = &task->wake_q;
+
+	/*
+	 * Atomically grab the task, if ->wake_q is !nil already it means
+	 * it's already queued (either by us or someone else) and will get the
+	 * wakeup due to that.
+	 *
+	 * In order to ensure that a pending wakeup will observe our pending
+	 * state, even in the failed case, an explicit smp_mb() must be used.
+	 */
+	smp_mb__before_atomic();
+	if (unlikely(cmpxchg_relaxed(&node->next, NULL, WAKE_Q_TAIL)))
+		return false;
+
+	/*
+	 * The head is context local, there can be no concurrency.
+	 */
+	*head->lastp = node;
+	head->lastp = &node->next;
+	return true;
+}
+
+/**
+ * wake_q_add() - queue a wakeup for 'later' waking.
+ * @head: the wake_q_head to add @task to
+ * @task: the task to queue for 'later' wakeup
+ *
+ * Queue a task for later wakeup, most likely by the wake_up_q() call in the
+ * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
+ * instantly.
+ *
+ * This function must be used as-if it were wake_up_process(); IOW the task
+ * must be ready to be woken at this location.
+ */
+void wake_q_add(struct wake_q_head *head, struct task_struct *task)
+{
+	if (__wake_q_add(head, task))
+		get_task_struct(task);
+}
+
+/**
+ * wake_q_add_safe() - safely queue a wakeup for 'later' waking.
+ * @head: the wake_q_head to add @task to
+ * @task: the task to queue for 'later' wakeup
+ *
+ * Queue a task for later wakeup, most likely by the wake_up_q() call in the
+ * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
+ * instantly.
+ *
+ * This function must be used as-if it were wake_up_process(); IOW the task
+ * must be ready to be woken at this location.
+ *
+ * This function is essentially a task-safe equivalent to wake_q_add(). Callers
+ * that already hold reference to @task can call the 'safe' version and trust
+ * wake_q to do the right thing depending whether or not the @task is already
+ * queued for wakeup.
+ */
+void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task)
+{
+	if (!__wake_q_add(head, task))
+		put_task_struct(task);
+}
+
+void wake_up_q(struct wake_q_head *head)
+{
+	struct wake_q_node *node = head->first;
+
+	while (node != WAKE_Q_TAIL) {
+		struct task_struct *task;
+
+		task = container_of(node, struct task_struct, wake_q);
+		/* Task can safely be re-inserted now: */
+		node = node->next;
+		task->wake_q.next = NULL;
+
+		/*
+		 * wake_up_process() executes a full barrier, which pairs with
+		 * the queueing in wake_q_add() so as not to miss wakeups.
+		 */
+		wake_up_process(task);
+		put_task_struct(task);
+	}
+}
+
+/*
+ * resched_curr - mark rq's current task 'to be rescheduled now'.
+ *
+ * On UP this means the setting of the need_resched flag, on SMP it
+ * might also involve a cross-CPU call to trigger the scheduler on
+ * the target CPU.
+ */
+void resched_curr(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+	int cpu;
+
+	lockdep_assert_rq_held(rq);
+
+	if (test_tsk_need_resched(curr))
+		return;
+
+	cpu = cpu_of(rq);
+
+	if (cpu == smp_processor_id()) {
+		set_tsk_need_resched(curr);
+		set_preempt_need_resched();
+		return;
+	}
+
+	if (set_nr_and_not_polling(curr))
+		smp_send_reschedule(cpu);
+	else
+		trace_sched_wake_idle_without_ipi(cpu);
+}
+
+void resched_cpu(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+	raw_spin_rq_lock_irqsave(rq, flags);
+	if (cpu_online(cpu) || cpu == smp_processor_id())
+		resched_curr(rq);
+	raw_spin_rq_unlock_irqrestore(rq, flags);
+}
+
+#ifdef CONFIG_SMP
+#ifdef CONFIG_NO_HZ_COMMON
+/*
+ * In the semi idle case, use the nearest busy CPU for migrating timers
+ * from an idle CPU.  This is good for power-savings.
+ *
+ * We don't do similar optimization for completely idle system, as
+ * selecting an idle CPU will add more delays to the timers than intended
+ * (as that CPU's timer base may not be uptodate wrt jiffies etc).
+ */
+int get_nohz_timer_target(void)
+{
+	int i, cpu = smp_processor_id(), default_cpu = -1;
+	struct sched_domain *sd;
+	const struct cpumask *hk_mask;
+
+	if (housekeeping_cpu(cpu, HK_TYPE_TIMER)) {
+		if (!idle_cpu(cpu))
+			return cpu;
+		default_cpu = cpu;
+	}
+
+	hk_mask = housekeeping_cpumask(HK_TYPE_TIMER);
+
+	rcu_read_lock();
+	for_each_domain(cpu, sd) {
+		for_each_cpu_and(i, sched_domain_span(sd), hk_mask) {
+			if (cpu == i)
+				continue;
+
+			if (!idle_cpu(i)) {
+				cpu = i;
+				goto unlock;
+			}
+		}
+	}
+
+	if (default_cpu == -1)
+		default_cpu = housekeeping_any_cpu(HK_TYPE_TIMER);
+	cpu = default_cpu;
+unlock:
+	rcu_read_unlock();
+	return cpu;
+}
+
+/*
+ * When add_timer_on() enqueues a timer into the timer wheel of an
+ * idle CPU then this timer might expire before the next timer event
+ * which is scheduled to wake up that CPU. In case of a completely
+ * idle system the next event might even be infinite time into the
+ * future. wake_up_idle_cpu() ensures that the CPU is woken up and
+ * leaves the inner idle loop so the newly added timer is taken into
+ * account when the CPU goes back to idle and evaluates the timer
+ * wheel for the next timer event.
+ */
+static void wake_up_idle_cpu(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (cpu == smp_processor_id())
+		return;
+
+	if (set_nr_and_not_polling(rq->idle))
+		smp_send_reschedule(cpu);
+	else
+		trace_sched_wake_idle_without_ipi(cpu);
+}
+
+static bool wake_up_full_nohz_cpu(int cpu)
+{
+	/*
+	 * We just need the target to call irq_exit() and re-evaluate
+	 * the next tick. The nohz full kick at least implies that.
+	 * If needed we can still optimize that later with an
+	 * empty IRQ.
+	 */
+	if (cpu_is_offline(cpu))
+		return true;  /* Don't try to wake offline CPUs. */
+	if (tick_nohz_full_cpu(cpu)) {
+		if (cpu != smp_processor_id() ||
+		    tick_nohz_tick_stopped())
+			tick_nohz_full_kick_cpu(cpu);
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * Wake up the specified CPU.  If the CPU is going offline, it is the
+ * caller's responsibility to deal with the lost wakeup, for example,
+ * by hooking into the CPU_DEAD notifier like timers and hrtimers do.
+ */
+void wake_up_nohz_cpu(int cpu)
+{
+	if (!wake_up_full_nohz_cpu(cpu))
+		wake_up_idle_cpu(cpu);
+}
+
+static void nohz_csd_func(void *info)
+{
+	struct rq *rq = info;
+	int cpu = cpu_of(rq);
+	unsigned int flags;
+
+	/*
+	 * Release the rq::nohz_csd.
+	 */
+	flags = atomic_fetch_andnot(NOHZ_KICK_MASK | NOHZ_NEWILB_KICK, nohz_flags(cpu));
+	WARN_ON(!(flags & NOHZ_KICK_MASK));
+
+	rq->idle_balance = idle_cpu(cpu);
+	if (rq->idle_balance && !need_resched()) {
+		rq->nohz_idle_balance = flags;
+		raise_softirq_irqoff(SCHED_SOFTIRQ);
+	}
+}
+
+#endif /* CONFIG_NO_HZ_COMMON */
+
+#ifdef CONFIG_NO_HZ_FULL
+bool sched_can_stop_tick(struct rq *rq)
+{
+	int fifo_nr_running;
+
+	/* Deadline tasks, even if single, need the tick */
+	if (rq->dl.dl_nr_running)
+		return false;
+
+	/*
+	 * If there are more than one RR tasks, we need the tick to affect the
+	 * actual RR behaviour.
+	 */
+	if (rq->rt.rr_nr_running) {
+		if (rq->rt.rr_nr_running == 1)
+			return true;
+		else
+			return false;
+	}
+
+	/*
+	 * If there's no RR tasks, but FIFO tasks, we can skip the tick, no
+	 * forced preemption between FIFO tasks.
+	 */
+	fifo_nr_running = rq->rt.rt_nr_running - rq->rt.rr_nr_running;
+	if (fifo_nr_running)
+		return true;
+
+	/*
+	 * If there are no DL,RR/FIFO tasks, there must only be CFS tasks left;
+	 * if there's more than one we need the tick for involuntary
+	 * preemption.
+	 */
+	if (rq->nr_running > 1)
+		return false;
+
+	return true;
+}
+#endif /* CONFIG_NO_HZ_FULL */
+#endif /* CONFIG_SMP */
+
+#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
+			(defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
+/*
+ * Iterate task_group tree rooted at *from, calling @down when first entering a
+ * node and @up when leaving it for the final time.
+ *
+ * Caller must hold rcu_lock or sufficient equivalent.
+ */
+int walk_tg_tree_from(struct task_group *from,
+			     tg_visitor down, tg_visitor up, void *data)
+{
+	struct task_group *parent, *child;
+	int ret;
+
+	parent = from;
+
+down:
+	ret = (*down)(parent, data);
+	if (ret)
+		goto out;
+	list_for_each_entry_rcu(child, &parent->children, siblings) {
+		parent = child;
+		goto down;
+
+up:
+		continue;
+	}
+	ret = (*up)(parent, data);
+	if (ret || parent == from)
+		goto out;
+
+	child = parent;
+	parent = parent->parent;
+	if (parent)
+		goto up;
+out:
+	return ret;
+}
+
+int tg_nop(struct task_group *tg, void *data)
+{
+	return 0;
+}
+#endif
+
+static void set_load_weight(struct task_struct *p, bool update_load)
+{
+	int prio = p->static_prio - MAX_RT_PRIO;
+	struct load_weight *load = &p->se.load;
+
+	/*
+	 * SCHED_IDLE tasks get minimal weight:
+	 */
+	if (task_has_idle_policy(p)) {
+		load->weight = scale_load(WEIGHT_IDLEPRIO);
+		load->inv_weight = WMULT_IDLEPRIO;
+		return;
+	}
+
+	/*
+	 * SCHED_OTHER tasks have to update their load when changing their
+	 * weight
+	 */
+	if (update_load && p->sched_class == &fair_sched_class) {
+		reweight_task(p, prio);
+	} else {
+		load->weight = scale_load(sched_prio_to_weight[prio]);
+		load->inv_weight = sched_prio_to_wmult[prio];
+	}
+}
+
+#ifdef CONFIG_UCLAMP_TASK
+/*
+ * Serializes updates of utilization clamp values
+ *
+ * The (slow-path) user-space triggers utilization clamp value updates which
+ * can require updates on (fast-path) scheduler's data structures used to
+ * support enqueue/dequeue operations.
+ * While the per-CPU rq lock protects fast-path update operations, user-space
+ * requests are serialized using a mutex to reduce the risk of conflicting
+ * updates or API abuses.
+ */
+static DEFINE_MUTEX(uclamp_mutex);
+
+/* Max allowed minimum utilization */
+static unsigned int __maybe_unused sysctl_sched_uclamp_util_min = SCHED_CAPACITY_SCALE;
+
+/* Max allowed maximum utilization */
+static unsigned int __maybe_unused sysctl_sched_uclamp_util_max = SCHED_CAPACITY_SCALE;
+
+/*
+ * By default RT tasks run at the maximum performance point/capacity of the
+ * system. Uclamp enforces this by always setting UCLAMP_MIN of RT tasks to
+ * SCHED_CAPACITY_SCALE.
+ *
+ * This knob allows admins to change the default behavior when uclamp is being
+ * used. In battery powered devices, particularly, running at the maximum
+ * capacity and frequency will increase energy consumption and shorten the
+ * battery life.
+ *
+ * This knob only affects RT tasks that their uclamp_se->user_defined == false.
+ *
+ * This knob will not override the system default sched_util_clamp_min defined
+ * above.
+ */
+static unsigned int sysctl_sched_uclamp_util_min_rt_default = SCHED_CAPACITY_SCALE;
+
+/* All clamps are required to be less or equal than these values */
+static struct uclamp_se uclamp_default[UCLAMP_CNT];
+
+/*
+ * This static key is used to reduce the uclamp overhead in the fast path. It
+ * primarily disables the call to uclamp_rq_{inc, dec}() in
+ * enqueue/dequeue_task().
+ *
+ * This allows users to continue to enable uclamp in their kernel config with
+ * minimum uclamp overhead in the fast path.
+ *
+ * As soon as userspace modifies any of the uclamp knobs, the static key is
+ * enabled, since we have an actual users that make use of uclamp
+ * functionality.
+ *
+ * The knobs that would enable this static key are:
+ *
+ *   * A task modifying its uclamp value with sched_setattr().
+ *   * An admin modifying the sysctl_sched_uclamp_{min, max} via procfs.
+ *   * An admin modifying the cgroup cpu.uclamp.{min, max}
+ */
+DEFINE_STATIC_KEY_FALSE(sched_uclamp_used);
+
+/* Integer rounded range for each bucket */
+#define UCLAMP_BUCKET_DELTA DIV_ROUND_CLOSEST(SCHED_CAPACITY_SCALE, UCLAMP_BUCKETS)
+
+#define for_each_clamp_id(clamp_id) \
+	for ((clamp_id) = 0; (clamp_id) < UCLAMP_CNT; (clamp_id)++)
+
+static inline unsigned int uclamp_bucket_id(unsigned int clamp_value)
+{
+	return min_t(unsigned int, clamp_value / UCLAMP_BUCKET_DELTA, UCLAMP_BUCKETS - 1);
+}
+
+static inline unsigned int uclamp_none(enum uclamp_id clamp_id)
+{
+	if (clamp_id == UCLAMP_MIN)
+		return 0;
+	return SCHED_CAPACITY_SCALE;
+}
+
+static inline void uclamp_se_set(struct uclamp_se *uc_se,
+				 unsigned int value, bool user_defined)
+{
+	uc_se->value = value;
+	uc_se->bucket_id = uclamp_bucket_id(value);
+	uc_se->user_defined = user_defined;
+}
+
+static inline unsigned int
+uclamp_idle_value(struct rq *rq, enum uclamp_id clamp_id,
+		  unsigned int clamp_value)
+{
+	/*
+	 * Avoid blocked utilization pushing up the frequency when we go
+	 * idle (which drops the max-clamp) by retaining the last known
+	 * max-clamp.
+	 */
+	if (clamp_id == UCLAMP_MAX) {
+		rq->uclamp_flags |= UCLAMP_FLAG_IDLE;
+		return clamp_value;
+	}
+
+	return uclamp_none(UCLAMP_MIN);
+}
+
+static inline void uclamp_idle_reset(struct rq *rq, enum uclamp_id clamp_id,
+				     unsigned int clamp_value)
+{
+	/* Reset max-clamp retention only on idle exit */
+	if (!(rq->uclamp_flags & UCLAMP_FLAG_IDLE))
+		return;
+
+	uclamp_rq_set(rq, clamp_id, clamp_value);
+}
+
+static inline
+unsigned int uclamp_rq_max_value(struct rq *rq, enum uclamp_id clamp_id,
+				   unsigned int clamp_value)
+{
+	struct uclamp_bucket *bucket = rq->uclamp[clamp_id].bucket;
+	int bucket_id = UCLAMP_BUCKETS - 1;
+
+	/*
+	 * Since both min and max clamps are max aggregated, find the
+	 * top most bucket with tasks in.
+	 */
+	for ( ; bucket_id >= 0; bucket_id--) {
+		if (!bucket[bucket_id].tasks)
+			continue;
+		return bucket[bucket_id].value;
+	}
+
+	/* No tasks -- default clamp values */
+	return uclamp_idle_value(rq, clamp_id, clamp_value);
+}
+
+static void __uclamp_update_util_min_rt_default(struct task_struct *p)
+{
+	unsigned int default_util_min;
+	struct uclamp_se *uc_se;
+
+	lockdep_assert_held(&p->pi_lock);
+
+	uc_se = &p->uclamp_req[UCLAMP_MIN];
+
+	/* Only sync if user didn't override the default */
+	if (uc_se->user_defined)
+		return;
+
+	default_util_min = sysctl_sched_uclamp_util_min_rt_default;
+	uclamp_se_set(uc_se, default_util_min, false);
+}
+
+static void uclamp_update_util_min_rt_default(struct task_struct *p)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (!rt_task(p))
+		return;
+
+	/* Protect updates to p->uclamp_* */
+	rq = task_rq_lock(p, &rf);
+	__uclamp_update_util_min_rt_default(p);
+	task_rq_unlock(rq, p, &rf);
+}
+
+static inline struct uclamp_se
+uclamp_tg_restrict(struct task_struct *p, enum uclamp_id clamp_id)
+{
+	/* Copy by value as we could modify it */
+	struct uclamp_se uc_req = p->uclamp_req[clamp_id];
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+	unsigned int tg_min, tg_max, value;
+
+	/*
+	 * Tasks in autogroups or root task group will be
+	 * restricted by system defaults.
+	 */
+	if (task_group_is_autogroup(task_group(p)))
+		return uc_req;
+	if (task_group(p) == &root_task_group)
+		return uc_req;
+
+	tg_min = task_group(p)->uclamp[UCLAMP_MIN].value;
+	tg_max = task_group(p)->uclamp[UCLAMP_MAX].value;
+	value = uc_req.value;
+	value = clamp(value, tg_min, tg_max);
+	uclamp_se_set(&uc_req, value, false);
+#endif
+
+	return uc_req;
+}
+
+/*
+ * The effective clamp bucket index of a task depends on, by increasing
+ * priority:
+ * - the task specific clamp value, when explicitly requested from userspace
+ * - the task group effective clamp value, for tasks not either in the root
+ *   group or in an autogroup
+ * - the system default clamp value, defined by the sysadmin
+ */
+static inline struct uclamp_se
+uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id)
+{
+	struct uclamp_se uc_req = uclamp_tg_restrict(p, clamp_id);
+	struct uclamp_se uc_max = uclamp_default[clamp_id];
+
+	/* System default restrictions always apply */
+	if (unlikely(uc_req.value > uc_max.value))
+		return uc_max;
+
+	return uc_req;
+}
+
+unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id)
+{
+	struct uclamp_se uc_eff;
+
+	/* Task currently refcounted: use back-annotated (effective) value */
+	if (p->uclamp[clamp_id].active)
+		return (unsigned long)p->uclamp[clamp_id].value;
+
+	uc_eff = uclamp_eff_get(p, clamp_id);
+
+	return (unsigned long)uc_eff.value;
+}
+
+/*
+ * When a task is enqueued on a rq, the clamp bucket currently defined by the
+ * task's uclamp::bucket_id is refcounted on that rq. This also immediately
+ * updates the rq's clamp value if required.
+ *
+ * Tasks can have a task-specific value requested from user-space, track
+ * within each bucket the maximum value for tasks refcounted in it.
+ * This "local max aggregation" allows to track the exact "requested" value
+ * for each bucket when all its RUNNABLE tasks require the same clamp.
+ */
+static inline void uclamp_rq_inc_id(struct rq *rq, struct task_struct *p,
+				    enum uclamp_id clamp_id)
+{
+	struct uclamp_rq *uc_rq = &rq->uclamp[clamp_id];
+	struct uclamp_se *uc_se = &p->uclamp[clamp_id];
+	struct uclamp_bucket *bucket;
+
+	lockdep_assert_rq_held(rq);
+
+	/* Update task effective clamp */
+	p->uclamp[clamp_id] = uclamp_eff_get(p, clamp_id);
+
+	bucket = &uc_rq->bucket[uc_se->bucket_id];
+	bucket->tasks++;
+	uc_se->active = true;
+
+	uclamp_idle_reset(rq, clamp_id, uc_se->value);
+
+	/*
+	 * Local max aggregation: rq buckets always track the max
+	 * "requested" clamp value of its RUNNABLE tasks.
+	 */
+	if (bucket->tasks == 1 || uc_se->value > bucket->value)
+		bucket->value = uc_se->value;
+
+	if (uc_se->value > uclamp_rq_get(rq, clamp_id))
+		uclamp_rq_set(rq, clamp_id, uc_se->value);
+}
+
+/*
+ * When a task is dequeued from a rq, the clamp bucket refcounted by the task
+ * is released. If this is the last task reference counting the rq's max
+ * active clamp value, then the rq's clamp value is updated.
+ *
+ * Both refcounted tasks and rq's cached clamp values are expected to be
+ * always valid. If it's detected they are not, as defensive programming,
+ * enforce the expected state and warn.
+ */
+static inline void uclamp_rq_dec_id(struct rq *rq, struct task_struct *p,
+				    enum uclamp_id clamp_id)
+{
+	struct uclamp_rq *uc_rq = &rq->uclamp[clamp_id];
+	struct uclamp_se *uc_se = &p->uclamp[clamp_id];
+	struct uclamp_bucket *bucket;
+	unsigned int bkt_clamp;
+	unsigned int rq_clamp;
+
+	lockdep_assert_rq_held(rq);
+
+	/*
+	 * If sched_uclamp_used was enabled after task @p was enqueued,
+	 * we could end up with unbalanced call to uclamp_rq_dec_id().
+	 *
+	 * In this case the uc_se->active flag should be false since no uclamp
+	 * accounting was performed at enqueue time and we can just return
+	 * here.
+	 *
+	 * Need to be careful of the following enqueue/dequeue ordering
+	 * problem too
+	 *
+	 *	enqueue(taskA)
+	 *	// sched_uclamp_used gets enabled
+	 *	enqueue(taskB)
+	 *	dequeue(taskA)
+	 *	// Must not decrement bucket->tasks here
+	 *	dequeue(taskB)
+	 *
+	 * where we could end up with stale data in uc_se and
+	 * bucket[uc_se->bucket_id].
+	 *
+	 * The following check here eliminates the possibility of such race.
+	 */
+	if (unlikely(!uc_se->active))
+		return;
+
+	bucket = &uc_rq->bucket[uc_se->bucket_id];
+
+	SCHED_WARN_ON(!bucket->tasks);
+	if (likely(bucket->tasks))
+		bucket->tasks--;
+
+	uc_se->active = false;
+
+	/*
+	 * Keep "local max aggregation" simple and accept to (possibly)
+	 * overboost some RUNNABLE tasks in the same bucket.
+	 * The rq clamp bucket value is reset to its base value whenever
+	 * there are no more RUNNABLE tasks refcounting it.
+	 */
+	if (likely(bucket->tasks))
+		return;
+
+	rq_clamp = uclamp_rq_get(rq, clamp_id);
+	/*
+	 * Defensive programming: this should never happen. If it happens,
+	 * e.g. due to future modification, warn and fixup the expected value.
+	 */
+	SCHED_WARN_ON(bucket->value > rq_clamp);
+	if (bucket->value >= rq_clamp) {
+		bkt_clamp = uclamp_rq_max_value(rq, clamp_id, uc_se->value);
+		uclamp_rq_set(rq, clamp_id, bkt_clamp);
+	}
+}
+
+static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p)
+{
+	enum uclamp_id clamp_id;
+
+	/*
+	 * Avoid any overhead until uclamp is actually used by the userspace.
+	 *
+	 * The condition is constructed such that a NOP is generated when
+	 * sched_uclamp_used is disabled.
+	 */
+	if (!static_branch_unlikely(&sched_uclamp_used))
+		return;
+
+	if (unlikely(!p->sched_class->uclamp_enabled))
+		return;
+
+	for_each_clamp_id(clamp_id)
+		uclamp_rq_inc_id(rq, p, clamp_id);
+
+	/* Reset clamp idle holding when there is one RUNNABLE task */
+	if (rq->uclamp_flags & UCLAMP_FLAG_IDLE)
+		rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE;
+}
+
+static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p)
+{
+	enum uclamp_id clamp_id;
+
+	/*
+	 * Avoid any overhead until uclamp is actually used by the userspace.
+	 *
+	 * The condition is constructed such that a NOP is generated when
+	 * sched_uclamp_used is disabled.
+	 */
+	if (!static_branch_unlikely(&sched_uclamp_used))
+		return;
+
+	if (unlikely(!p->sched_class->uclamp_enabled))
+		return;
+
+	for_each_clamp_id(clamp_id)
+		uclamp_rq_dec_id(rq, p, clamp_id);
+}
+
+static inline void uclamp_rq_reinc_id(struct rq *rq, struct task_struct *p,
+				      enum uclamp_id clamp_id)
+{
+	if (!p->uclamp[clamp_id].active)
+		return;
+
+	uclamp_rq_dec_id(rq, p, clamp_id);
+	uclamp_rq_inc_id(rq, p, clamp_id);
+
+	/*
+	 * Make sure to clear the idle flag if we've transiently reached 0
+	 * active tasks on rq.
+	 */
+	if (clamp_id == UCLAMP_MAX && (rq->uclamp_flags & UCLAMP_FLAG_IDLE))
+		rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE;
+}
+
+static inline void
+uclamp_update_active(struct task_struct *p)
+{
+	enum uclamp_id clamp_id;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	/*
+	 * Lock the task and the rq where the task is (or was) queued.
+	 *
+	 * We might lock the (previous) rq of a !RUNNABLE task, but that's the
+	 * price to pay to safely serialize util_{min,max} updates with
+	 * enqueues, dequeues and migration operations.
+	 * This is the same locking schema used by __set_cpus_allowed_ptr().
+	 */
+	rq = task_rq_lock(p, &rf);
+
+	/*
+	 * Setting the clamp bucket is serialized by task_rq_lock().
+	 * If the task is not yet RUNNABLE and its task_struct is not
+	 * affecting a valid clamp bucket, the next time it's enqueued,
+	 * it will already see the updated clamp bucket value.
+	 */
+	for_each_clamp_id(clamp_id)
+		uclamp_rq_reinc_id(rq, p, clamp_id);
+
+	task_rq_unlock(rq, p, &rf);
+}
+
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+static inline void
+uclamp_update_active_tasks(struct cgroup_subsys_state *css)
+{
+	struct css_task_iter it;
+	struct task_struct *p;
+
+	css_task_iter_start(css, 0, &it);
+	while ((p = css_task_iter_next(&it)))
+		uclamp_update_active(p);
+	css_task_iter_end(&it);
+}
+
+static void cpu_util_update_eff(struct cgroup_subsys_state *css);
+#endif
+
+#ifdef CONFIG_SYSCTL
+#ifdef CONFIG_UCLAMP_TASK
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+static void uclamp_update_root_tg(void)
+{
+	struct task_group *tg = &root_task_group;
+
+	uclamp_se_set(&tg->uclamp_req[UCLAMP_MIN],
+		      sysctl_sched_uclamp_util_min, false);
+	uclamp_se_set(&tg->uclamp_req[UCLAMP_MAX],
+		      sysctl_sched_uclamp_util_max, false);
+
+	rcu_read_lock();
+	cpu_util_update_eff(&root_task_group.css);
+	rcu_read_unlock();
+}
+#else
+static void uclamp_update_root_tg(void) { }
+#endif
+
+static void uclamp_sync_util_min_rt_default(void)
+{
+	struct task_struct *g, *p;
+
+	/*
+	 * copy_process()			sysctl_uclamp
+	 *					  uclamp_min_rt = X;
+	 *   write_lock(&tasklist_lock)		  read_lock(&tasklist_lock)
+	 *   // link thread			  smp_mb__after_spinlock()
+	 *   write_unlock(&tasklist_lock)	  read_unlock(&tasklist_lock);
+	 *   sched_post_fork()			  for_each_process_thread()
+	 *     __uclamp_sync_rt()		    __uclamp_sync_rt()
+	 *
+	 * Ensures that either sched_post_fork() will observe the new
+	 * uclamp_min_rt or for_each_process_thread() will observe the new
+	 * task.
+	 */
+	read_lock(&tasklist_lock);
+	smp_mb__after_spinlock();
+	read_unlock(&tasklist_lock);
+
+	rcu_read_lock();
+	for_each_process_thread(g, p)
+		uclamp_update_util_min_rt_default(p);
+	rcu_read_unlock();
+}
+
+static int sysctl_sched_uclamp_handler(struct ctl_table *table, int write,
+				void *buffer, size_t *lenp, loff_t *ppos)
+{
+	bool update_root_tg = false;
+	int old_min, old_max, old_min_rt;
+	int result;
+
+	mutex_lock(&uclamp_mutex);
+	old_min = sysctl_sched_uclamp_util_min;
+	old_max = sysctl_sched_uclamp_util_max;
+	old_min_rt = sysctl_sched_uclamp_util_min_rt_default;
+
+	result = proc_dointvec(table, write, buffer, lenp, ppos);
+	if (result)
+		goto undo;
+	if (!write)
+		goto done;
+
+	if (sysctl_sched_uclamp_util_min > sysctl_sched_uclamp_util_max ||
+	    sysctl_sched_uclamp_util_max > SCHED_CAPACITY_SCALE	||
+	    sysctl_sched_uclamp_util_min_rt_default > SCHED_CAPACITY_SCALE) {
+
+		result = -EINVAL;
+		goto undo;
+	}
+
+	if (old_min != sysctl_sched_uclamp_util_min) {
+		uclamp_se_set(&uclamp_default[UCLAMP_MIN],
+			      sysctl_sched_uclamp_util_min, false);
+		update_root_tg = true;
+	}
+	if (old_max != sysctl_sched_uclamp_util_max) {
+		uclamp_se_set(&uclamp_default[UCLAMP_MAX],
+			      sysctl_sched_uclamp_util_max, false);
+		update_root_tg = true;
+	}
+
+	if (update_root_tg) {
+		static_branch_enable(&sched_uclamp_used);
+		uclamp_update_root_tg();
+	}
+
+	if (old_min_rt != sysctl_sched_uclamp_util_min_rt_default) {
+		static_branch_enable(&sched_uclamp_used);
+		uclamp_sync_util_min_rt_default();
+	}
+
+	/*
+	 * We update all RUNNABLE tasks only when task groups are in use.
+	 * Otherwise, keep it simple and do just a lazy update at each next
+	 * task enqueue time.
+	 */
+
+	goto done;
+
+undo:
+	sysctl_sched_uclamp_util_min = old_min;
+	sysctl_sched_uclamp_util_max = old_max;
+	sysctl_sched_uclamp_util_min_rt_default = old_min_rt;
+done:
+	mutex_unlock(&uclamp_mutex);
+
+	return result;
+}
+#endif
+#endif
+
+static int uclamp_validate(struct task_struct *p,
+			   const struct sched_attr *attr)
+{
+	int util_min = p->uclamp_req[UCLAMP_MIN].value;
+	int util_max = p->uclamp_req[UCLAMP_MAX].value;
+
+	if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN) {
+		util_min = attr->sched_util_min;
+
+		if (util_min + 1 > SCHED_CAPACITY_SCALE + 1)
+			return -EINVAL;
+	}
+
+	if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX) {
+		util_max = attr->sched_util_max;
+
+		if (util_max + 1 > SCHED_CAPACITY_SCALE + 1)
+			return -EINVAL;
+	}
+
+	if (util_min != -1 && util_max != -1 && util_min > util_max)
+		return -EINVAL;
+
+	/*
+	 * We have valid uclamp attributes; make sure uclamp is enabled.
+	 *
+	 * We need to do that here, because enabling static branches is a
+	 * blocking operation which obviously cannot be done while holding
+	 * scheduler locks.
+	 */
+	static_branch_enable(&sched_uclamp_used);
+
+	return 0;
+}
+
+static bool uclamp_reset(const struct sched_attr *attr,
+			 enum uclamp_id clamp_id,
+			 struct uclamp_se *uc_se)
+{
+	/* Reset on sched class change for a non user-defined clamp value. */
+	if (likely(!(attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)) &&
+	    !uc_se->user_defined)
+		return true;
+
+	/* Reset on sched_util_{min,max} == -1. */
+	if (clamp_id == UCLAMP_MIN &&
+	    attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN &&
+	    attr->sched_util_min == -1) {
+		return true;
+	}
+
+	if (clamp_id == UCLAMP_MAX &&
+	    attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX &&
+	    attr->sched_util_max == -1) {
+		return true;
+	}
+
+	return false;
+}
+
+static void __setscheduler_uclamp(struct task_struct *p,
+				  const struct sched_attr *attr)
+{
+	enum uclamp_id clamp_id;
+
+	for_each_clamp_id(clamp_id) {
+		struct uclamp_se *uc_se = &p->uclamp_req[clamp_id];
+		unsigned int value;
+
+		if (!uclamp_reset(attr, clamp_id, uc_se))
+			continue;
+
+		/*
+		 * RT by default have a 100% boost value that could be modified
+		 * at runtime.
+		 */
+		if (unlikely(rt_task(p) && clamp_id == UCLAMP_MIN))
+			value = sysctl_sched_uclamp_util_min_rt_default;
+		else
+			value = uclamp_none(clamp_id);
+
+		uclamp_se_set(uc_se, value, false);
+
+	}
+
+	if (likely(!(attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)))
+		return;
+
+	if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN &&
+	    attr->sched_util_min != -1) {
+		uclamp_se_set(&p->uclamp_req[UCLAMP_MIN],
+			      attr->sched_util_min, true);
+	}
+
+	if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX &&
+	    attr->sched_util_max != -1) {
+		uclamp_se_set(&p->uclamp_req[UCLAMP_MAX],
+			      attr->sched_util_max, true);
+	}
+}
+
+static void uclamp_fork(struct task_struct *p)
+{
+	enum uclamp_id clamp_id;
+
+	/*
+	 * We don't need to hold task_rq_lock() when updating p->uclamp_* here
+	 * as the task is still at its early fork stages.
+	 */
+	for_each_clamp_id(clamp_id)
+		p->uclamp[clamp_id].active = false;
+
+	if (likely(!p->sched_reset_on_fork))
+		return;
+
+	for_each_clamp_id(clamp_id) {
+		uclamp_se_set(&p->uclamp_req[clamp_id],
+			      uclamp_none(clamp_id), false);
+	}
+}
+
+static void uclamp_post_fork(struct task_struct *p)
+{
+	uclamp_update_util_min_rt_default(p);
+}
+
+static void __init init_uclamp_rq(struct rq *rq)
+{
+	enum uclamp_id clamp_id;
+	struct uclamp_rq *uc_rq = rq->uclamp;
+
+	for_each_clamp_id(clamp_id) {
+		uc_rq[clamp_id] = (struct uclamp_rq) {
+			.value = uclamp_none(clamp_id)
+		};
+	}
+
+	rq->uclamp_flags = UCLAMP_FLAG_IDLE;
+}
+
+static void __init init_uclamp(void)
+{
+	struct uclamp_se uc_max = {};
+	enum uclamp_id clamp_id;
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		init_uclamp_rq(cpu_rq(cpu));
+
+	for_each_clamp_id(clamp_id) {
+		uclamp_se_set(&init_task.uclamp_req[clamp_id],
+			      uclamp_none(clamp_id), false);
+	}
+
+	/* System defaults allow max clamp values for both indexes */
+	uclamp_se_set(&uc_max, uclamp_none(UCLAMP_MAX), false);
+	for_each_clamp_id(clamp_id) {
+		uclamp_default[clamp_id] = uc_max;
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+		root_task_group.uclamp_req[clamp_id] = uc_max;
+		root_task_group.uclamp[clamp_id] = uc_max;
+#endif
+	}
+}
+
+#else /* CONFIG_UCLAMP_TASK */
+static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p) { }
+static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p) { }
+static inline int uclamp_validate(struct task_struct *p,
+				  const struct sched_attr *attr)
+{
+	return -EOPNOTSUPP;
+}
+static void __setscheduler_uclamp(struct task_struct *p,
+				  const struct sched_attr *attr) { }
+static inline void uclamp_fork(struct task_struct *p) { }
+static inline void uclamp_post_fork(struct task_struct *p) { }
+static inline void init_uclamp(void) { }
+#endif /* CONFIG_UCLAMP_TASK */
+
+bool sched_task_on_rq(struct task_struct *p)
+{
+	return task_on_rq_queued(p);
+}
+
+unsigned long get_wchan(struct task_struct *p)
+{
+	unsigned long ip = 0;
+	unsigned int state;
+
+	if (!p || p == current)
+		return 0;
+
+	/* Only get wchan if task is blocked and we can keep it that way. */
+	raw_spin_lock_irq(&p->pi_lock);
+	state = READ_ONCE(p->__state);
+	smp_rmb(); /* see try_to_wake_up() */
+	if (state != TASK_RUNNING && state != TASK_WAKING && !p->on_rq)
+		ip = __get_wchan(p);
+	raw_spin_unlock_irq(&p->pi_lock);
+
+	return ip;
+}
+
+static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
+{
+	if (!(flags & ENQUEUE_NOCLOCK))
+		update_rq_clock(rq);
+
+	if (!(flags & ENQUEUE_RESTORE)) {
+		sched_info_enqueue(rq, p);
+		psi_enqueue(p, flags & ENQUEUE_WAKEUP);
+	}
+
+	uclamp_rq_inc(rq, p);
+	p->sched_class->enqueue_task(rq, p, flags);
+
+	if (sched_core_enabled(rq))
+		sched_core_enqueue(rq, p);
+}
+
+static inline void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
+{
+	if (sched_core_enabled(rq))
+		sched_core_dequeue(rq, p, flags);
+
+	if (!(flags & DEQUEUE_NOCLOCK))
+		update_rq_clock(rq);
+
+	if (!(flags & DEQUEUE_SAVE)) {
+		sched_info_dequeue(rq, p);
+		psi_dequeue(p, flags & DEQUEUE_SLEEP);
+	}
+
+	uclamp_rq_dec(rq, p);
+	p->sched_class->dequeue_task(rq, p, flags);
+}
+
+void activate_task(struct rq *rq, struct task_struct *p, int flags)
+{
+	if (task_on_rq_migrating(p))
+		flags |= ENQUEUE_MIGRATED;
+
+	enqueue_task(rq, p, flags);
+
+	p->on_rq = TASK_ON_RQ_QUEUED;
+}
+
+void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
+{
+	p->on_rq = (flags & DEQUEUE_SLEEP) ? 0 : TASK_ON_RQ_MIGRATING;
+
+	dequeue_task(rq, p, flags);
+}
+
+static inline int __normal_prio(int policy, int rt_prio, int nice)
+{
+	int prio;
+
+	if (dl_policy(policy))
+		prio = MAX_DL_PRIO - 1;
+	else if (rt_policy(policy))
+		prio = MAX_RT_PRIO - 1 - rt_prio;
+	else
+		prio = NICE_TO_PRIO(nice);
+
+	return prio;
+}
+
+/*
+ * Calculate the expected normal priority: i.e. priority
+ * without taking RT-inheritance into account. Might be
+ * boosted by interactivity modifiers. Changes upon fork,
+ * setprio syscalls, and whenever the interactivity
+ * estimator recalculates.
+ */
+static inline int normal_prio(struct task_struct *p)
+{
+	return __normal_prio(p->policy, p->rt_priority, PRIO_TO_NICE(p->static_prio));
+}
+
+/*
+ * Calculate the current priority, i.e. the priority
+ * taken into account by the scheduler. This value might
+ * be boosted by RT tasks, or might be boosted by
+ * interactivity modifiers. Will be RT if the task got
+ * RT-boosted. If not then it returns p->normal_prio.
+ */
+static int effective_prio(struct task_struct *p)
+{
+	p->normal_prio = normal_prio(p);
+	/*
+	 * If we are RT tasks or we were boosted to RT priority,
+	 * keep the priority unchanged. Otherwise, update priority
+	 * to the normal priority:
+	 */
+	if (!rt_prio(p->prio))
+		return p->normal_prio;
+	return p->prio;
+}
+
+/**
+ * task_curr - is this task currently executing on a CPU?
+ * @p: the task in question.
+ *
+ * Return: 1 if the task is currently executing. 0 otherwise.
+ */
+inline int task_curr(const struct task_struct *p)
+{
+	return cpu_curr(task_cpu(p)) == p;
+}
+
+/*
+ * switched_from, switched_to and prio_changed must _NOT_ drop rq->lock,
+ * use the balance_callback list if you want balancing.
+ *
+ * this means any call to check_class_changed() must be followed by a call to
+ * balance_callback().
+ */
+static inline void check_class_changed(struct rq *rq, struct task_struct *p,
+				       const struct sched_class *prev_class,
+				       int oldprio)
+{
+	if (prev_class != p->sched_class) {
+		if (prev_class->switched_from)
+			prev_class->switched_from(rq, p);
+
+		p->sched_class->switched_to(rq, p);
+	} else if (oldprio != p->prio || dl_task(p))
+		p->sched_class->prio_changed(rq, p, oldprio);
+}
+
+void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
+{
+	if (p->sched_class == rq->curr->sched_class)
+		rq->curr->sched_class->check_preempt_curr(rq, p, flags);
+	else if (sched_class_above(p->sched_class, rq->curr->sched_class))
+		resched_curr(rq);
+
+	/*
+	 * A queue event has occurred, and we're going to schedule.  In
+	 * this case, we can save a useless back to back clock update.
+	 */
+	if (task_on_rq_queued(rq->curr) && test_tsk_need_resched(rq->curr))
+		rq_clock_skip_update(rq);
+}
+
+#ifdef CONFIG_SMP
+
+static void
+__do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask, u32 flags);
+
+static int __set_cpus_allowed_ptr(struct task_struct *p,
+				  const struct cpumask *new_mask,
+				  u32 flags);
+
+static void migrate_disable_switch(struct rq *rq, struct task_struct *p)
+{
+	if (likely(!p->migration_disabled))
+		return;
+
+	if (p->cpus_ptr != &p->cpus_mask)
+		return;
+
+	/*
+	 * Violates locking rules! see comment in __do_set_cpus_allowed().
+	 */
+	__do_set_cpus_allowed(p, cpumask_of(rq->cpu), SCA_MIGRATE_DISABLE);
+}
+
+void migrate_disable(void)
+{
+	struct task_struct *p = current;
+
+	if (p->migration_disabled) {
+		p->migration_disabled++;
+		return;
+	}
+
+	preempt_disable();
+	this_rq()->nr_pinned++;
+	p->migration_disabled = 1;
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(migrate_disable);
+
+void migrate_enable(void)
+{
+	struct task_struct *p = current;
+
+	if (p->migration_disabled > 1) {
+		p->migration_disabled--;
+		return;
+	}
+
+	if (WARN_ON_ONCE(!p->migration_disabled))
+		return;
+
+	/*
+	 * Ensure stop_task runs either before or after this, and that
+	 * __set_cpus_allowed_ptr(SCA_MIGRATE_ENABLE) doesn't schedule().
+	 */
+	preempt_disable();
+	if (p->cpus_ptr != &p->cpus_mask)
+		__set_cpus_allowed_ptr(p, &p->cpus_mask, SCA_MIGRATE_ENABLE);
+	/*
+	 * Mustn't clear migration_disabled() until cpus_ptr points back at the
+	 * regular cpus_mask, otherwise things that race (eg.
+	 * select_fallback_rq) get confused.
+	 */
+	barrier();
+	p->migration_disabled = 0;
+	this_rq()->nr_pinned--;
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(migrate_enable);
+
+static inline bool rq_has_pinned_tasks(struct rq *rq)
+{
+	return rq->nr_pinned;
+}
+
+/*
+ * Per-CPU kthreads are allowed to run on !active && online CPUs, see
+ * __set_cpus_allowed_ptr() and select_fallback_rq().
+ */
+static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
+{
+	/* When not in the task's cpumask, no point in looking further. */
+	if (!cpumask_test_cpu(cpu, p->cpus_ptr))
+		return false;
+
+	/* migrate_disabled() must be allowed to finish. */
+	if (is_migration_disabled(p))
+		return cpu_online(cpu);
+
+	/* Non kernel threads are not allowed during either online or offline. */
+	if (!(p->flags & PF_KTHREAD))
+		return cpu_active(cpu) && task_cpu_possible(cpu, p);
+
+	/* KTHREAD_IS_PER_CPU is always allowed. */
+	if (kthread_is_per_cpu(p))
+		return cpu_online(cpu);
+
+	/* Regular kernel threads don't get to stay during offline. */
+	if (cpu_dying(cpu))
+		return false;
+
+	/* But are allowed during online. */
+	return cpu_online(cpu);
+}
+
+/*
+ * This is how migration works:
+ *
+ * 1) we invoke migration_cpu_stop() on the target CPU using
+ *    stop_one_cpu().
+ * 2) stopper starts to run (implicitly forcing the migrated thread
+ *    off the CPU)
+ * 3) it checks whether the migrated task is still in the wrong runqueue.
+ * 4) if it's in the wrong runqueue then the migration thread removes
+ *    it and puts it into the right queue.
+ * 5) stopper completes and stop_one_cpu() returns and the migration
+ *    is done.
+ */
+
+/*
+ * move_queued_task - move a queued task to new rq.
+ *
+ * Returns (locked) new rq. Old rq's lock is released.
+ */
+static struct rq *move_queued_task(struct rq *rq, struct rq_flags *rf,
+				   struct task_struct *p, int new_cpu)
+{
+	lockdep_assert_rq_held(rq);
+
+	deactivate_task(rq, p, DEQUEUE_NOCLOCK);
+	set_task_cpu(p, new_cpu);
+	rq_unlock(rq, rf);
+
+	rq = cpu_rq(new_cpu);
+
+	rq_lock(rq, rf);
+	WARN_ON_ONCE(task_cpu(p) != new_cpu);
+	activate_task(rq, p, 0);
+	check_preempt_curr(rq, p, 0);
+
+	return rq;
+}
+
+struct migration_arg {
+	struct task_struct		*task;
+	int				dest_cpu;
+	struct set_affinity_pending	*pending;
+};
+
+/*
+ * @refs: number of wait_for_completion()
+ * @stop_pending: is @stop_work in use
+ */
+struct set_affinity_pending {
+	refcount_t		refs;
+	unsigned int		stop_pending;
+	struct completion	done;
+	struct cpu_stop_work	stop_work;
+	struct migration_arg	arg;
+};
+
+/*
+ * Move (not current) task off this CPU, onto the destination CPU. We're doing
+ * this because either it can't run here any more (set_cpus_allowed()
+ * away from this CPU, or CPU going down), or because we're
+ * attempting to rebalance this task on exec (sched_exec).
+ *
+ * So we race with normal scheduler movements, but that's OK, as long
+ * as the task is no longer on this CPU.
+ */
+static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf,
+				 struct task_struct *p, int dest_cpu)
+{
+	/* Affinity changed (again). */
+	if (!is_cpu_allowed(p, dest_cpu))
+		return rq;
+
+	update_rq_clock(rq);
+	rq = move_queued_task(rq, rf, p, dest_cpu);
+
+	return rq;
+}
+
+/*
+ * migration_cpu_stop - this will be executed by a highprio stopper thread
+ * and performs thread migration by bumping thread off CPU then
+ * 'pushing' onto another runqueue.
+ */
+static int migration_cpu_stop(void *data)
+{
+	struct migration_arg *arg = data;
+	struct set_affinity_pending *pending = arg->pending;
+	struct task_struct *p = arg->task;
+	struct rq *rq = this_rq();
+	bool complete = false;
+	struct rq_flags rf;
+
+	/*
+	 * The original target CPU might have gone down and we might
+	 * be on another CPU but it doesn't matter.
+	 */
+	local_irq_save(rf.flags);
+	/*
+	 * We need to explicitly wake pending tasks before running
+	 * __migrate_task() such that we will not miss enforcing cpus_ptr
+	 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
+	 */
+	flush_smp_call_function_queue();
+
+	raw_spin_lock(&p->pi_lock);
+	rq_lock(rq, &rf);
+
+	/*
+	 * If we were passed a pending, then ->stop_pending was set, thus
+	 * p->migration_pending must have remained stable.
+	 */
+	WARN_ON_ONCE(pending && pending != p->migration_pending);
+
+	/*
+	 * If task_rq(p) != rq, it cannot be migrated here, because we're
+	 * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
+	 * we're holding p->pi_lock.
+	 */
+	if (task_rq(p) == rq) {
+		if (is_migration_disabled(p))
+			goto out;
+
+		if (pending) {
+			p->migration_pending = NULL;
+			complete = true;
+
+			if (cpumask_test_cpu(task_cpu(p), &p->cpus_mask))
+				goto out;
+		}
+
+		if (task_on_rq_queued(p))
+			rq = __migrate_task(rq, &rf, p, arg->dest_cpu);
+		else
+			p->wake_cpu = arg->dest_cpu;
+
+		/*
+		 * XXX __migrate_task() can fail, at which point we might end
+		 * up running on a dodgy CPU, AFAICT this can only happen
+		 * during CPU hotplug, at which point we'll get pushed out
+		 * anyway, so it's probably not a big deal.
+		 */
+
+	} else if (pending) {
+		/*
+		 * This happens when we get migrated between migrate_enable()'s
+		 * preempt_enable() and scheduling the stopper task. At that
+		 * point we're a regular task again and not current anymore.
+		 *
+		 * A !PREEMPT kernel has a giant hole here, which makes it far
+		 * more likely.
+		 */
+
+		/*
+		 * The task moved before the stopper got to run. We're holding
+		 * ->pi_lock, so the allowed mask is stable - if it got
+		 * somewhere allowed, we're done.
+		 */
+		if (cpumask_test_cpu(task_cpu(p), p->cpus_ptr)) {
+			p->migration_pending = NULL;
+			complete = true;
+			goto out;
+		}
+
+		/*
+		 * When migrate_enable() hits a rq mis-match we can't reliably
+		 * determine is_migration_disabled() and so have to chase after
+		 * it.
+		 */
+		WARN_ON_ONCE(!pending->stop_pending);
+		preempt_disable();
+		task_rq_unlock(rq, p, &rf);
+		stop_one_cpu_nowait(task_cpu(p), migration_cpu_stop,
+				    &pending->arg, &pending->stop_work);
+		preempt_enable();
+		return 0;
+	}
+out:
+	if (pending)
+		pending->stop_pending = false;
+	task_rq_unlock(rq, p, &rf);
+
+	if (complete)
+		complete_all(&pending->done);
+
+	return 0;
+}
+
+int push_cpu_stop(void *arg)
+{
+	struct rq *lowest_rq = NULL, *rq = this_rq();
+	struct task_struct *p = arg;
+
+	raw_spin_lock_irq(&p->pi_lock);
+	raw_spin_rq_lock(rq);
+
+	if (task_rq(p) != rq)
+		goto out_unlock;
+
+	if (is_migration_disabled(p)) {
+		p->migration_flags |= MDF_PUSH;
+		goto out_unlock;
+	}
+
+	p->migration_flags &= ~MDF_PUSH;
+
+	if (p->sched_class->find_lock_rq)
+		lowest_rq = p->sched_class->find_lock_rq(p, rq);
+
+	if (!lowest_rq)
+		goto out_unlock;
+
+	// XXX validate p is still the highest prio task
+	if (task_rq(p) == rq) {
+		deactivate_task(rq, p, 0);
+		set_task_cpu(p, lowest_rq->cpu);
+		activate_task(lowest_rq, p, 0);
+		resched_curr(lowest_rq);
+	}
+
+	double_unlock_balance(rq, lowest_rq);
+
+out_unlock:
+	rq->push_busy = false;
+	raw_spin_rq_unlock(rq);
+	raw_spin_unlock_irq(&p->pi_lock);
+
+	put_task_struct(p);
+	return 0;
+}
+
+/*
+ * sched_class::set_cpus_allowed must do the below, but is not required to
+ * actually call this function.
+ */
+void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask, u32 flags)
+{
+	if (flags & (SCA_MIGRATE_ENABLE | SCA_MIGRATE_DISABLE)) {
+		p->cpus_ptr = new_mask;
+		return;
+	}
+
+	cpumask_copy(&p->cpus_mask, new_mask);
+	p->nr_cpus_allowed = cpumask_weight(new_mask);
+}
+
+static void
+__do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask, u32 flags)
+{
+	struct rq *rq = task_rq(p);
+	bool queued, running;
+
+	/*
+	 * This here violates the locking rules for affinity, since we're only
+	 * supposed to change these variables while holding both rq->lock and
+	 * p->pi_lock.
+	 *
+	 * HOWEVER, it magically works, because ttwu() is the only code that
+	 * accesses these variables under p->pi_lock and only does so after
+	 * smp_cond_load_acquire(&p->on_cpu, !VAL), and we're in __schedule()
+	 * before finish_task().
+	 *
+	 * XXX do further audits, this smells like something putrid.
+	 */
+	if (flags & SCA_MIGRATE_DISABLE)
+		SCHED_WARN_ON(!p->on_cpu);
+	else
+		lockdep_assert_held(&p->pi_lock);
+
+	queued = task_on_rq_queued(p);
+	running = task_current(rq, p);
+
+	if (queued) {
+		/*
+		 * Because __kthread_bind() calls this on blocked tasks without
+		 * holding rq->lock.
+		 */
+		lockdep_assert_rq_held(rq);
+		dequeue_task(rq, p, DEQUEUE_SAVE | DEQUEUE_NOCLOCK);
+	}
+	if (running)
+		put_prev_task(rq, p);
+
+	p->sched_class->set_cpus_allowed(p, new_mask, flags);
+
+	if (queued)
+		enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
+	if (running)
+		set_next_task(rq, p);
+}
+
+void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
+{
+	__do_set_cpus_allowed(p, new_mask, 0);
+}
+
+int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src,
+		      int node)
+{
+	cpumask_t *user_mask;
+	unsigned long flags;
+
+	/*
+	 * Always clear dst->user_cpus_ptr first as their user_cpus_ptr's
+	 * may differ by now due to racing.
+	 */
+	dst->user_cpus_ptr = NULL;
+
+	/*
+	 * This check is racy and losing the race is a valid situation.
+	 * It is not worth the extra overhead of taking the pi_lock on
+	 * every fork/clone.
+	 */
+	if (data_race(!src->user_cpus_ptr))
+		return 0;
+
+	user_mask = kmalloc_node(cpumask_size(), GFP_KERNEL, node);
+	if (!user_mask)
+		return -ENOMEM;
+
+	/*
+	 * Use pi_lock to protect content of user_cpus_ptr
+	 *
+	 * Though unlikely, user_cpus_ptr can be reset to NULL by a concurrent
+	 * do_set_cpus_allowed().
+	 */
+	raw_spin_lock_irqsave(&src->pi_lock, flags);
+	if (src->user_cpus_ptr) {
+		swap(dst->user_cpus_ptr, user_mask);
+		cpumask_copy(dst->user_cpus_ptr, src->user_cpus_ptr);
+	}
+	raw_spin_unlock_irqrestore(&src->pi_lock, flags);
+
+	if (unlikely(user_mask))
+		kfree(user_mask);
+
+	return 0;
+}
+
+static inline struct cpumask *clear_user_cpus_ptr(struct task_struct *p)
+{
+	struct cpumask *user_mask = NULL;
+
+	swap(p->user_cpus_ptr, user_mask);
+
+	return user_mask;
+}
+
+void release_user_cpus_ptr(struct task_struct *p)
+{
+	kfree(clear_user_cpus_ptr(p));
+}
+
+/*
+ * This function is wildly self concurrent; here be dragons.
+ *
+ *
+ * When given a valid mask, __set_cpus_allowed_ptr() must block until the
+ * designated task is enqueued on an allowed CPU. If that task is currently
+ * running, we have to kick it out using the CPU stopper.
+ *
+ * Migrate-Disable comes along and tramples all over our nice sandcastle.
+ * Consider:
+ *
+ *     Initial conditions: P0->cpus_mask = [0, 1]
+ *
+ *     P0@CPU0                  P1
+ *
+ *     migrate_disable();
+ *     <preempted>
+ *                              set_cpus_allowed_ptr(P0, [1]);
+ *
+ * P1 *cannot* return from this set_cpus_allowed_ptr() call until P0 executes
+ * its outermost migrate_enable() (i.e. it exits its Migrate-Disable region).
+ * This means we need the following scheme:
+ *
+ *     P0@CPU0                  P1
+ *
+ *     migrate_disable();
+ *     <preempted>
+ *                              set_cpus_allowed_ptr(P0, [1]);
+ *                                <blocks>
+ *     <resumes>
+ *     migrate_enable();
+ *       __set_cpus_allowed_ptr();
+ *       <wakes local stopper>
+ *                         `--> <woken on migration completion>
+ *
+ * Now the fun stuff: there may be several P1-like tasks, i.e. multiple
+ * concurrent set_cpus_allowed_ptr(P0, [*]) calls. CPU affinity changes of any
+ * task p are serialized by p->pi_lock, which we can leverage: the one that
+ * should come into effect at the end of the Migrate-Disable region is the last
+ * one. This means we only need to track a single cpumask (i.e. p->cpus_mask),
+ * but we still need to properly signal those waiting tasks at the appropriate
+ * moment.
+ *
+ * This is implemented using struct set_affinity_pending. The first
+ * __set_cpus_allowed_ptr() caller within a given Migrate-Disable region will
+ * setup an instance of that struct and install it on the targeted task_struct.
+ * Any and all further callers will reuse that instance. Those then wait for
+ * a completion signaled at the tail of the CPU stopper callback (1), triggered
+ * on the end of the Migrate-Disable region (i.e. outermost migrate_enable()).
+ *
+ *
+ * (1) In the cases covered above. There is one more where the completion is
+ * signaled within affine_move_task() itself: when a subsequent affinity request
+ * occurs after the stopper bailed out due to the targeted task still being
+ * Migrate-Disable. Consider:
+ *
+ *     Initial conditions: P0->cpus_mask = [0, 1]
+ *
+ *     CPU0		  P1				P2
+ *     <P0>
+ *       migrate_disable();
+ *       <preempted>
+ *                        set_cpus_allowed_ptr(P0, [1]);
+ *                          <blocks>
+ *     <migration/0>
+ *       migration_cpu_stop()
+ *         is_migration_disabled()
+ *           <bails>
+ *                                                       set_cpus_allowed_ptr(P0, [0, 1]);
+ *                                                         <signal completion>
+ *                          <awakes>
+ *
+ * Note that the above is safe vs a concurrent migrate_enable(), as any
+ * pending affinity completion is preceded by an uninstallation of
+ * p->migration_pending done with p->pi_lock held.
+ */
+static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flags *rf,
+			    int dest_cpu, unsigned int flags)
+{
+	struct set_affinity_pending my_pending = { }, *pending = NULL;
+	bool stop_pending, complete = false;
+
+	/* Can the task run on the task's current CPU? If so, we're done */
+	if (cpumask_test_cpu(task_cpu(p), &p->cpus_mask)) {
+		struct task_struct *push_task = NULL;
+
+		if ((flags & SCA_MIGRATE_ENABLE) &&
+		    (p->migration_flags & MDF_PUSH) && !rq->push_busy) {
+			rq->push_busy = true;
+			push_task = get_task_struct(p);
+		}
+
+		/*
+		 * If there are pending waiters, but no pending stop_work,
+		 * then complete now.
+		 */
+		pending = p->migration_pending;
+		if (pending && !pending->stop_pending) {
+			p->migration_pending = NULL;
+			complete = true;
+		}
+
+		preempt_disable();
+		task_rq_unlock(rq, p, rf);
+		if (push_task) {
+			stop_one_cpu_nowait(rq->cpu, push_cpu_stop,
+					    p, &rq->push_work);
+		}
+		preempt_enable();
+
+		if (complete)
+			complete_all(&pending->done);
+
+		return 0;
+	}
+
+	if (!(flags & SCA_MIGRATE_ENABLE)) {
+		/* serialized by p->pi_lock */
+		if (!p->migration_pending) {
+			/* Install the request */
+			refcount_set(&my_pending.refs, 1);
+			init_completion(&my_pending.done);
+			my_pending.arg = (struct migration_arg) {
+				.task = p,
+				.dest_cpu = dest_cpu,
+				.pending = &my_pending,
+			};
+
+			p->migration_pending = &my_pending;
+		} else {
+			pending = p->migration_pending;
+			refcount_inc(&pending->refs);
+			/*
+			 * Affinity has changed, but we've already installed a
+			 * pending. migration_cpu_stop() *must* see this, else
+			 * we risk a completion of the pending despite having a
+			 * task on a disallowed CPU.
+			 *
+			 * Serialized by p->pi_lock, so this is safe.
+			 */
+			pending->arg.dest_cpu = dest_cpu;
+		}
+	}
+	pending = p->migration_pending;
+	/*
+	 * - !MIGRATE_ENABLE:
+	 *   we'll have installed a pending if there wasn't one already.
+	 *
+	 * - MIGRATE_ENABLE:
+	 *   we're here because the current CPU isn't matching anymore,
+	 *   the only way that can happen is because of a concurrent
+	 *   set_cpus_allowed_ptr() call, which should then still be
+	 *   pending completion.
+	 *
+	 * Either way, we really should have a @pending here.
+	 */
+	if (WARN_ON_ONCE(!pending)) {
+		task_rq_unlock(rq, p, rf);
+		return -EINVAL;
+	}
+
+	if (task_on_cpu(rq, p) || READ_ONCE(p->__state) == TASK_WAKING) {
+		/*
+		 * MIGRATE_ENABLE gets here because 'p == current', but for
+		 * anything else we cannot do is_migration_disabled(), punt
+		 * and have the stopper function handle it all race-free.
+		 */
+		stop_pending = pending->stop_pending;
+		if (!stop_pending)
+			pending->stop_pending = true;
+
+		if (flags & SCA_MIGRATE_ENABLE)
+			p->migration_flags &= ~MDF_PUSH;
+
+		preempt_disable();
+		task_rq_unlock(rq, p, rf);
+		if (!stop_pending) {
+			stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
+					    &pending->arg, &pending->stop_work);
+		}
+		preempt_enable();
+
+		if (flags & SCA_MIGRATE_ENABLE)
+			return 0;
+	} else {
+
+		if (!is_migration_disabled(p)) {
+			if (task_on_rq_queued(p))
+				rq = move_queued_task(rq, rf, p, dest_cpu);
+
+			if (!pending->stop_pending) {
+				p->migration_pending = NULL;
+				complete = true;
+			}
+		}
+		task_rq_unlock(rq, p, rf);
+
+		if (complete)
+			complete_all(&pending->done);
+	}
+
+	wait_for_completion(&pending->done);
+
+	if (refcount_dec_and_test(&pending->refs))
+		wake_up_var(&pending->refs); /* No UaF, just an address */
+
+	/*
+	 * Block the original owner of &pending until all subsequent callers
+	 * have seen the completion and decremented the refcount
+	 */
+	wait_var_event(&my_pending.refs, !refcount_read(&my_pending.refs));
+
+	/* ARGH */
+	WARN_ON_ONCE(my_pending.stop_pending);
+
+	return 0;
+}
+
+/*
+ * Called with both p->pi_lock and rq->lock held; drops both before returning.
+ */
+static int __set_cpus_allowed_ptr_locked(struct task_struct *p,
+					 const struct cpumask *new_mask,
+					 u32 flags,
+					 struct rq *rq,
+					 struct rq_flags *rf)
+	__releases(rq->lock)
+	__releases(p->pi_lock)
+{
+	const struct cpumask *cpu_allowed_mask = task_cpu_possible_mask(p);
+	const struct cpumask *cpu_valid_mask = cpu_active_mask;
+	bool kthread = p->flags & PF_KTHREAD;
+	struct cpumask *user_mask = NULL;
+	unsigned int dest_cpu;
+	int ret = 0;
+
+	update_rq_clock(rq);
+
+	if (kthread || is_migration_disabled(p)) {
+		/*
+		 * Kernel threads are allowed on online && !active CPUs,
+		 * however, during cpu-hot-unplug, even these might get pushed
+		 * away if not KTHREAD_IS_PER_CPU.
+		 *
+		 * Specifically, migration_disabled() tasks must not fail the
+		 * cpumask_any_and_distribute() pick below, esp. so on
+		 * SCA_MIGRATE_ENABLE, otherwise we'll not call
+		 * set_cpus_allowed_common() and actually reset p->cpus_ptr.
+		 */
+		cpu_valid_mask = cpu_online_mask;
+	}
+
+	if (!kthread && !cpumask_subset(new_mask, cpu_allowed_mask)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Must re-check here, to close a race against __kthread_bind(),
+	 * sched_setaffinity() is not guaranteed to observe the flag.
+	 */
+	if ((flags & SCA_CHECK) && (p->flags & PF_NO_SETAFFINITY)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (!(flags & SCA_MIGRATE_ENABLE)) {
+		if (cpumask_equal(&p->cpus_mask, new_mask))
+			goto out;
+
+		if (WARN_ON_ONCE(p == current &&
+				 is_migration_disabled(p) &&
+				 !cpumask_test_cpu(task_cpu(p), new_mask))) {
+			ret = -EBUSY;
+			goto out;
+		}
+	}
+
+	/*
+	 * Picking a ~random cpu helps in cases where we are changing affinity
+	 * for groups of tasks (ie. cpuset), so that load balancing is not
+	 * immediately required to distribute the tasks within their new mask.
+	 */
+	dest_cpu = cpumask_any_and_distribute(cpu_valid_mask, new_mask);
+	if (dest_cpu >= nr_cpu_ids) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	__do_set_cpus_allowed(p, new_mask, flags);
+
+	if (flags & SCA_USER)
+		user_mask = clear_user_cpus_ptr(p);
+
+	ret = affine_move_task(rq, p, rf, dest_cpu, flags);
+
+	kfree(user_mask);
+
+	return ret;
+
+out:
+	task_rq_unlock(rq, p, rf);
+
+	return ret;
+}
+
+/*
+ * Change a given task's CPU affinity. Migrate the thread to a
+ * proper CPU and schedule it away if the CPU it's executing on
+ * is removed from the allowed bitmask.
+ *
+ * NOTE: the caller must have a valid reference to the task, the
+ * task must not exit() & deallocate itself prematurely. The
+ * call is not atomic; no spinlocks may be held.
+ */
+static int __set_cpus_allowed_ptr(struct task_struct *p,
+				  const struct cpumask *new_mask, u32 flags)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(p, &rf);
+	return __set_cpus_allowed_ptr_locked(p, new_mask, flags, rq, &rf);
+}
+
+int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
+{
+	return __set_cpus_allowed_ptr(p, new_mask, 0);
+}
+EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
+
+/*
+ * Change a given task's CPU affinity to the intersection of its current
+ * affinity mask and @subset_mask, writing the resulting mask to @new_mask
+ * and pointing @p->user_cpus_ptr to a copy of the old mask.
+ * If the resulting mask is empty, leave the affinity unchanged and return
+ * -EINVAL.
+ */
+static int restrict_cpus_allowed_ptr(struct task_struct *p,
+				     struct cpumask *new_mask,
+				     const struct cpumask *subset_mask)
+{
+	struct cpumask *user_mask = NULL;
+	struct rq_flags rf;
+	struct rq *rq;
+	int err;
+
+	if (!p->user_cpus_ptr) {
+		user_mask = kmalloc(cpumask_size(), GFP_KERNEL);
+		if (!user_mask)
+			return -ENOMEM;
+	}
+
+	rq = task_rq_lock(p, &rf);
+
+	/*
+	 * Forcefully restricting the affinity of a deadline task is
+	 * likely to cause problems, so fail and noisily override the
+	 * mask entirely.
+	 */
+	if (task_has_dl_policy(p) && dl_bandwidth_enabled()) {
+		err = -EPERM;
+		goto err_unlock;
+	}
+
+	if (!cpumask_and(new_mask, &p->cpus_mask, subset_mask)) {
+		err = -EINVAL;
+		goto err_unlock;
+	}
+
+	/*
+	 * We're about to butcher the task affinity, so keep track of what
+	 * the user asked for in case we're able to restore it later on.
+	 */
+	if (user_mask) {
+		cpumask_copy(user_mask, p->cpus_ptr);
+		p->user_cpus_ptr = user_mask;
+	}
+
+	return __set_cpus_allowed_ptr_locked(p, new_mask, 0, rq, &rf);
+
+err_unlock:
+	task_rq_unlock(rq, p, &rf);
+	kfree(user_mask);
+	return err;
+}
+
+/*
+ * Restrict the CPU affinity of task @p so that it is a subset of
+ * task_cpu_possible_mask() and point @p->user_cpu_ptr to a copy of the
+ * old affinity mask. If the resulting mask is empty, we warn and walk
+ * up the cpuset hierarchy until we find a suitable mask.
+ */
+void force_compatible_cpus_allowed_ptr(struct task_struct *p)
+{
+	cpumask_var_t new_mask;
+	const struct cpumask *override_mask = task_cpu_possible_mask(p);
+
+	alloc_cpumask_var(&new_mask, GFP_KERNEL);
+
+	/*
+	 * __migrate_task() can fail silently in the face of concurrent
+	 * offlining of the chosen destination CPU, so take the hotplug
+	 * lock to ensure that the migration succeeds.
+	 */
+	cpus_read_lock();
+	if (!cpumask_available(new_mask))
+		goto out_set_mask;
+
+	if (!restrict_cpus_allowed_ptr(p, new_mask, override_mask))
+		goto out_free_mask;
+
+	/*
+	 * We failed to find a valid subset of the affinity mask for the
+	 * task, so override it based on its cpuset hierarchy.
+	 */
+	cpuset_cpus_allowed(p, new_mask);
+	override_mask = new_mask;
+
+out_set_mask:
+	if (printk_ratelimit()) {
+		printk_deferred("Overriding affinity for process %d (%s) to CPUs %*pbl\n",
+				task_pid_nr(p), p->comm,
+				cpumask_pr_args(override_mask));
+	}
+
+	WARN_ON(set_cpus_allowed_ptr(p, override_mask));
+out_free_mask:
+	cpus_read_unlock();
+	free_cpumask_var(new_mask);
+}
+
+static int
+__sched_setaffinity(struct task_struct *p, const struct cpumask *mask);
+
+/*
+ * Restore the affinity of a task @p which was previously restricted by a
+ * call to force_compatible_cpus_allowed_ptr(). This will clear (and free)
+ * @p->user_cpus_ptr.
+ *
+ * It is the caller's responsibility to serialise this with any calls to
+ * force_compatible_cpus_allowed_ptr(@p).
+ */
+void relax_compatible_cpus_allowed_ptr(struct task_struct *p)
+{
+	struct cpumask *user_mask = p->user_cpus_ptr;
+	unsigned long flags;
+
+	/*
+	 * Try to restore the old affinity mask. If this fails, then
+	 * we free the mask explicitly to avoid it being inherited across
+	 * a subsequent fork().
+	 */
+	if (!user_mask || !__sched_setaffinity(p, user_mask))
+		return;
+
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	user_mask = clear_user_cpus_ptr(p);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+
+	kfree(user_mask);
+}
+
+void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
+{
+#ifdef CONFIG_SCHED_DEBUG
+	unsigned int state = READ_ONCE(p->__state);
+
+	/*
+	 * We should never call set_task_cpu() on a blocked task,
+	 * ttwu() will sort out the placement.
+	 */
+	WARN_ON_ONCE(state != TASK_RUNNING && state != TASK_WAKING && !p->on_rq);
+
+	/*
+	 * Migrating fair class task must have p->on_rq = TASK_ON_RQ_MIGRATING,
+	 * because schedstat_wait_{start,end} rebase migrating task's wait_start
+	 * time relying on p->on_rq.
+	 */
+	WARN_ON_ONCE(state == TASK_RUNNING &&
+		     p->sched_class == &fair_sched_class &&
+		     (p->on_rq && !task_on_rq_migrating(p)));
+
+#ifdef CONFIG_LOCKDEP
+	/*
+	 * The caller should hold either p->pi_lock or rq->lock, when changing
+	 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
+	 *
+	 * sched_move_task() holds both and thus holding either pins the cgroup,
+	 * see task_group().
+	 *
+	 * Furthermore, all task_rq users should acquire both locks, see
+	 * task_rq_lock().
+	 */
+	WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
+				      lockdep_is_held(__rq_lockp(task_rq(p)))));
+#endif
+	/*
+	 * Clearly, migrating tasks to offline CPUs is a fairly daft thing.
+	 */
+	WARN_ON_ONCE(!cpu_online(new_cpu));
+
+	WARN_ON_ONCE(is_migration_disabled(p));
+#endif
+
+	trace_sched_migrate_task(p, new_cpu);
+
+	if (task_cpu(p) != new_cpu) {
+		if (p->sched_class->migrate_task_rq)
+			p->sched_class->migrate_task_rq(p, new_cpu);
+		p->se.nr_migrations++;
+		rseq_migrate(p);
+		perf_event_task_migrate(p);
+	}
+
+	__set_task_cpu(p, new_cpu);
+}
+
+#ifdef CONFIG_NUMA_BALANCING
+static void __migrate_swap_task(struct task_struct *p, int cpu)
+{
+	if (task_on_rq_queued(p)) {
+		struct rq *src_rq, *dst_rq;
+		struct rq_flags srf, drf;
+
+		src_rq = task_rq(p);
+		dst_rq = cpu_rq(cpu);
+
+		rq_pin_lock(src_rq, &srf);
+		rq_pin_lock(dst_rq, &drf);
+
+		deactivate_task(src_rq, p, 0);
+		set_task_cpu(p, cpu);
+		activate_task(dst_rq, p, 0);
+		check_preempt_curr(dst_rq, p, 0);
+
+		rq_unpin_lock(dst_rq, &drf);
+		rq_unpin_lock(src_rq, &srf);
+
+	} else {
+		/*
+		 * Task isn't running anymore; make it appear like we migrated
+		 * it before it went to sleep. This means on wakeup we make the
+		 * previous CPU our target instead of where it really is.
+		 */
+		p->wake_cpu = cpu;
+	}
+}
+
+struct migration_swap_arg {
+	struct task_struct *src_task, *dst_task;
+	int src_cpu, dst_cpu;
+};
+
+static int migrate_swap_stop(void *data)
+{
+	struct migration_swap_arg *arg = data;
+	struct rq *src_rq, *dst_rq;
+	int ret = -EAGAIN;
+
+	if (!cpu_active(arg->src_cpu) || !cpu_active(arg->dst_cpu))
+		return -EAGAIN;
+
+	src_rq = cpu_rq(arg->src_cpu);
+	dst_rq = cpu_rq(arg->dst_cpu);
+
+	double_raw_lock(&arg->src_task->pi_lock,
+			&arg->dst_task->pi_lock);
+	double_rq_lock(src_rq, dst_rq);
+
+	if (task_cpu(arg->dst_task) != arg->dst_cpu)
+		goto unlock;
+
+	if (task_cpu(arg->src_task) != arg->src_cpu)
+		goto unlock;
+
+	if (!cpumask_test_cpu(arg->dst_cpu, arg->src_task->cpus_ptr))
+		goto unlock;
+
+	if (!cpumask_test_cpu(arg->src_cpu, arg->dst_task->cpus_ptr))
+		goto unlock;
+
+	__migrate_swap_task(arg->src_task, arg->dst_cpu);
+	__migrate_swap_task(arg->dst_task, arg->src_cpu);
+
+	ret = 0;
+
+unlock:
+	double_rq_unlock(src_rq, dst_rq);
+	raw_spin_unlock(&arg->dst_task->pi_lock);
+	raw_spin_unlock(&arg->src_task->pi_lock);
+
+	return ret;
+}
+
+/*
+ * Cross migrate two tasks
+ */
+int migrate_swap(struct task_struct *cur, struct task_struct *p,
+		int target_cpu, int curr_cpu)
+{
+	struct migration_swap_arg arg;
+	int ret = -EINVAL;
+
+	arg = (struct migration_swap_arg){
+		.src_task = cur,
+		.src_cpu = curr_cpu,
+		.dst_task = p,
+		.dst_cpu = target_cpu,
+	};
+
+	if (arg.src_cpu == arg.dst_cpu)
+		goto out;
+
+	/*
+	 * These three tests are all lockless; this is OK since all of them
+	 * will be re-checked with proper locks held further down the line.
+	 */
+	if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu))
+		goto out;
+
+	if (!cpumask_test_cpu(arg.dst_cpu, arg.src_task->cpus_ptr))
+		goto out;
+
+	if (!cpumask_test_cpu(arg.src_cpu, arg.dst_task->cpus_ptr))
+		goto out;
+
+	trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu);
+	ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg);
+
+out:
+	return ret;
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
+/*
+ * wait_task_inactive - wait for a thread to unschedule.
+ *
+ * Wait for the thread to block in any of the states set in @match_state.
+ * If it changes, i.e. @p might have woken up, then return zero.  When we
+ * succeed in waiting for @p to be off its CPU, we return a positive number
+ * (its total switch count).  If a second call a short while later returns the
+ * same number, the caller can be sure that @p has remained unscheduled the
+ * whole time.
+ *
+ * The caller must ensure that the task *will* unschedule sometime soon,
+ * else this function might spin for a *long* time. This function can't
+ * be called with interrupts off, or it may introduce deadlock with
+ * smp_call_function() if an IPI is sent by the same process we are
+ * waiting to become inactive.
+ */
+unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state)
+{
+	int running, queued;
+	struct rq_flags rf;
+	unsigned long ncsw;
+	struct rq *rq;
+
+	for (;;) {
+		/*
+		 * We do the initial early heuristics without holding
+		 * any task-queue locks at all. We'll only try to get
+		 * the runqueue lock when things look like they will
+		 * work out!
+		 */
+		rq = task_rq(p);
+
+		/*
+		 * If the task is actively running on another CPU
+		 * still, just relax and busy-wait without holding
+		 * any locks.
+		 *
+		 * NOTE! Since we don't hold any locks, it's not
+		 * even sure that "rq" stays as the right runqueue!
+		 * But we don't care, since "task_on_cpu()" will
+		 * return false if the runqueue has changed and p
+		 * is actually now running somewhere else!
+		 */
+		while (task_on_cpu(rq, p)) {
+			if (!(READ_ONCE(p->__state) & match_state))
+				return 0;
+			cpu_relax();
+		}
+
+		/*
+		 * Ok, time to look more closely! We need the rq
+		 * lock now, to be *sure*. If we're wrong, we'll
+		 * just go back and repeat.
+		 */
+		rq = task_rq_lock(p, &rf);
+		trace_sched_wait_task(p);
+		running = task_on_cpu(rq, p);
+		queued = task_on_rq_queued(p);
+		ncsw = 0;
+		if (READ_ONCE(p->__state) & match_state)
+			ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
+		task_rq_unlock(rq, p, &rf);
+
+		/*
+		 * If it changed from the expected state, bail out now.
+		 */
+		if (unlikely(!ncsw))
+			break;
+
+		/*
+		 * Was it really running after all now that we
+		 * checked with the proper locks actually held?
+		 *
+		 * Oops. Go back and try again..
+		 */
+		if (unlikely(running)) {
+			cpu_relax();
+			continue;
+		}
+
+		/*
+		 * It's not enough that it's not actively running,
+		 * it must be off the runqueue _entirely_, and not
+		 * preempted!
+		 *
+		 * So if it was still runnable (but just not actively
+		 * running right now), it's preempted, and we should
+		 * yield - it could be a while.
+		 */
+		if (unlikely(queued)) {
+			ktime_t to = NSEC_PER_SEC / HZ;
+
+			set_current_state(TASK_UNINTERRUPTIBLE);
+			schedule_hrtimeout(&to, HRTIMER_MODE_REL_HARD);
+			continue;
+		}
+
+		/*
+		 * Ahh, all good. It wasn't running, and it wasn't
+		 * runnable, which means that it will never become
+		 * running in the future either. We're all done!
+		 */
+		break;
+	}
+
+	return ncsw;
+}
+
+/***
+ * kick_process - kick a running thread to enter/exit the kernel
+ * @p: the to-be-kicked thread
+ *
+ * Cause a process which is running on another CPU to enter
+ * kernel-mode, without any delay. (to get signals handled.)
+ *
+ * NOTE: this function doesn't have to take the runqueue lock,
+ * because all it wants to ensure is that the remote task enters
+ * the kernel. If the IPI races and the task has been migrated
+ * to another CPU then no harm is done and the purpose has been
+ * achieved as well.
+ */
+void kick_process(struct task_struct *p)
+{
+	int cpu;
+
+	preempt_disable();
+	cpu = task_cpu(p);
+	if ((cpu != smp_processor_id()) && task_curr(p))
+		smp_send_reschedule(cpu);
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(kick_process);
+
+/*
+ * ->cpus_ptr is protected by both rq->lock and p->pi_lock
+ *
+ * A few notes on cpu_active vs cpu_online:
+ *
+ *  - cpu_active must be a subset of cpu_online
+ *
+ *  - on CPU-up we allow per-CPU kthreads on the online && !active CPU,
+ *    see __set_cpus_allowed_ptr(). At this point the newly online
+ *    CPU isn't yet part of the sched domains, and balancing will not
+ *    see it.
+ *
+ *  - on CPU-down we clear cpu_active() to mask the sched domains and
+ *    avoid the load balancer to place new tasks on the to be removed
+ *    CPU. Existing tasks will remain running there and will be taken
+ *    off.
+ *
+ * This means that fallback selection must not select !active CPUs.
+ * And can assume that any active CPU must be online. Conversely
+ * select_task_rq() below may allow selection of !active CPUs in order
+ * to satisfy the above rules.
+ */
+static int select_fallback_rq(int cpu, struct task_struct *p)
+{
+	int nid = cpu_to_node(cpu);
+	const struct cpumask *nodemask = NULL;
+	enum { cpuset, possible, fail } state = cpuset;
+	int dest_cpu;
+
+	/*
+	 * If the node that the CPU is on has been offlined, cpu_to_node()
+	 * will return -1. There is no CPU on the node, and we should
+	 * select the CPU on the other node.
+	 */
+	if (nid != -1) {
+		nodemask = cpumask_of_node(nid);
+
+		/* Look for allowed, online CPU in same node. */
+		for_each_cpu(dest_cpu, nodemask) {
+			if (is_cpu_allowed(p, dest_cpu))
+				return dest_cpu;
+		}
+	}
+
+	for (;;) {
+		/* Any allowed, online CPU? */
+		for_each_cpu(dest_cpu, p->cpus_ptr) {
+			if (!is_cpu_allowed(p, dest_cpu))
+				continue;
+
+			goto out;
+		}
+
+		/* No more Mr. Nice Guy. */
+		switch (state) {
+		case cpuset:
+			if (cpuset_cpus_allowed_fallback(p)) {
+				state = possible;
+				break;
+			}
+			fallthrough;
+		case possible:
+			/*
+			 * XXX When called from select_task_rq() we only
+			 * hold p->pi_lock and again violate locking order.
+			 *
+			 * More yuck to audit.
+			 */
+			do_set_cpus_allowed(p, task_cpu_possible_mask(p));
+			state = fail;
+			break;
+		case fail:
+			BUG();
+			break;
+		}
+	}
+
+out:
+	if (state != cpuset) {
+		/*
+		 * Don't tell them about moving exiting tasks or
+		 * kernel threads (both mm NULL), since they never
+		 * leave kernel.
+		 */
+		if (p->mm && printk_ratelimit()) {
+			printk_deferred("process %d (%s) no longer affine to cpu%d\n",
+					task_pid_nr(p), p->comm, cpu);
+		}
+	}
+
+	return dest_cpu;
+}
+
+/*
+ * The caller (fork, wakeup) owns p->pi_lock, ->cpus_ptr is stable.
+ */
+static inline
+int select_task_rq(struct task_struct *p, int cpu, int wake_flags)
+{
+	lockdep_assert_held(&p->pi_lock);
+
+	if (p->nr_cpus_allowed > 1 && !is_migration_disabled(p))
+		cpu = p->sched_class->select_task_rq(p, cpu, wake_flags);
+	else
+		cpu = cpumask_any(p->cpus_ptr);
+
+	/*
+	 * In order not to call set_task_cpu() on a blocking task we need
+	 * to rely on ttwu() to place the task on a valid ->cpus_ptr
+	 * CPU.
+	 *
+	 * Since this is common to all placement strategies, this lives here.
+	 *
+	 * [ this allows ->select_task() to simply return task_cpu(p) and
+	 *   not worry about this generic constraint ]
+	 */
+	if (unlikely(!is_cpu_allowed(p, cpu)))
+		cpu = select_fallback_rq(task_cpu(p), p);
+
+	return cpu;
+}
+
+void sched_set_stop_task(int cpu, struct task_struct *stop)
+{
+	static struct lock_class_key stop_pi_lock;
+	struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
+	struct task_struct *old_stop = cpu_rq(cpu)->stop;
+
+	if (stop) {
+		/*
+		 * Make it appear like a SCHED_FIFO task, its something
+		 * userspace knows about and won't get confused about.
+		 *
+		 * Also, it will make PI more or less work without too
+		 * much confusion -- but then, stop work should not
+		 * rely on PI working anyway.
+		 */
+		sched_setscheduler_nocheck(stop, SCHED_FIFO, &param);
+
+		stop->sched_class = &stop_sched_class;
+
+		/*
+		 * The PI code calls rt_mutex_setprio() with ->pi_lock held to
+		 * adjust the effective priority of a task. As a result,
+		 * rt_mutex_setprio() can trigger (RT) balancing operations,
+		 * which can then trigger wakeups of the stop thread to push
+		 * around the current task.
+		 *
+		 * The stop task itself will never be part of the PI-chain, it
+		 * never blocks, therefore that ->pi_lock recursion is safe.
+		 * Tell lockdep about this by placing the stop->pi_lock in its
+		 * own class.
+		 */
+		lockdep_set_class(&stop->pi_lock, &stop_pi_lock);
+	}
+
+	cpu_rq(cpu)->stop = stop;
+
+	if (old_stop) {
+		/*
+		 * Reset it back to a normal scheduling class so that
+		 * it can die in pieces.
+		 */
+		old_stop->sched_class = &rt_sched_class;
+	}
+}
+
+#else /* CONFIG_SMP */
+
+static inline int __set_cpus_allowed_ptr(struct task_struct *p,
+					 const struct cpumask *new_mask,
+					 u32 flags)
+{
+	return set_cpus_allowed_ptr(p, new_mask);
+}
+
+static inline void migrate_disable_switch(struct rq *rq, struct task_struct *p) { }
+
+static inline bool rq_has_pinned_tasks(struct rq *rq)
+{
+	return false;
+}
+
+#endif /* !CONFIG_SMP */
+
+static void
+ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
+{
+	struct rq *rq;
+
+	if (!schedstat_enabled())
+		return;
+
+	rq = this_rq();
+
+#ifdef CONFIG_SMP
+	if (cpu == rq->cpu) {
+		__schedstat_inc(rq->ttwu_local);
+		__schedstat_inc(p->stats.nr_wakeups_local);
+	} else {
+		struct sched_domain *sd;
+
+		__schedstat_inc(p->stats.nr_wakeups_remote);
+		rcu_read_lock();
+		for_each_domain(rq->cpu, sd) {
+			if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
+				__schedstat_inc(sd->ttwu_wake_remote);
+				break;
+			}
+		}
+		rcu_read_unlock();
+	}
+
+	if (wake_flags & WF_MIGRATED)
+		__schedstat_inc(p->stats.nr_wakeups_migrate);
+#endif /* CONFIG_SMP */
+
+	__schedstat_inc(rq->ttwu_count);
+	__schedstat_inc(p->stats.nr_wakeups);
+
+	if (wake_flags & WF_SYNC)
+		__schedstat_inc(p->stats.nr_wakeups_sync);
+}
+
+/*
+ * Mark the task runnable and perform wakeup-preemption.
+ */
+static void ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags,
+			   struct rq_flags *rf)
+{
+	check_preempt_curr(rq, p, wake_flags);
+	WRITE_ONCE(p->__state, TASK_RUNNING);
+	trace_sched_wakeup(p);
+
+#ifdef CONFIG_SMP
+	if (p->sched_class->task_woken) {
+		/*
+		 * Our task @p is fully woken up and running; so it's safe to
+		 * drop the rq->lock, hereafter rq is only used for statistics.
+		 */
+		rq_unpin_lock(rq, rf);
+		p->sched_class->task_woken(rq, p);
+		rq_repin_lock(rq, rf);
+	}
+
+	if (rq->idle_stamp) {
+		u64 delta = rq_clock(rq) - rq->idle_stamp;
+		u64 max = 2*rq->max_idle_balance_cost;
+
+		update_avg(&rq->avg_idle, delta);
+
+		if (rq->avg_idle > max)
+			rq->avg_idle = max;
+
+		rq->wake_stamp = jiffies;
+		rq->wake_avg_idle = rq->avg_idle / 2;
+
+		rq->idle_stamp = 0;
+	}
+#endif
+}
+
+static void
+ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags,
+		 struct rq_flags *rf)
+{
+	int en_flags = ENQUEUE_WAKEUP | ENQUEUE_NOCLOCK;
+
+	lockdep_assert_rq_held(rq);
+
+	if (p->sched_contributes_to_load)
+		rq->nr_uninterruptible--;
+
+#ifdef CONFIG_SMP
+	if (wake_flags & WF_MIGRATED)
+		en_flags |= ENQUEUE_MIGRATED;
+	else
+#endif
+	if (p->in_iowait) {
+		delayacct_blkio_end(p);
+		atomic_dec(&task_rq(p)->nr_iowait);
+	}
+
+	activate_task(rq, p, en_flags);
+	ttwu_do_wakeup(rq, p, wake_flags, rf);
+}
+
+/*
+ * Consider @p being inside a wait loop:
+ *
+ *   for (;;) {
+ *      set_current_state(TASK_UNINTERRUPTIBLE);
+ *
+ *      if (CONDITION)
+ *         break;
+ *
+ *      schedule();
+ *   }
+ *   __set_current_state(TASK_RUNNING);
+ *
+ * between set_current_state() and schedule(). In this case @p is still
+ * runnable, so all that needs doing is change p->state back to TASK_RUNNING in
+ * an atomic manner.
+ *
+ * By taking task_rq(p)->lock we serialize against schedule(), if @p->on_rq
+ * then schedule() must still happen and p->state can be changed to
+ * TASK_RUNNING. Otherwise we lost the race, schedule() has happened, and we
+ * need to do a full wakeup with enqueue.
+ *
+ * Returns: %true when the wakeup is done,
+ *          %false otherwise.
+ */
+static int ttwu_runnable(struct task_struct *p, int wake_flags)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+	int ret = 0;
+
+	rq = __task_rq_lock(p, &rf);
+	if (task_on_rq_queued(p)) {
+		/* check_preempt_curr() may use rq clock */
+		update_rq_clock(rq);
+		ttwu_do_wakeup(rq, p, wake_flags, &rf);
+		ret = 1;
+	}
+	__task_rq_unlock(rq, &rf);
+
+	return ret;
+}
+
+#ifdef CONFIG_SMP
+void sched_ttwu_pending(void *arg)
+{
+	struct llist_node *llist = arg;
+	struct rq *rq = this_rq();
+	struct task_struct *p, *t;
+	struct rq_flags rf;
+
+	if (!llist)
+		return;
+
+	/*
+	 * rq::ttwu_pending racy indication of out-standing wakeups.
+	 * Races such that false-negatives are possible, since they
+	 * are shorter lived that false-positives would be.
+	 */
+	WRITE_ONCE(rq->ttwu_pending, 0);
+
+	rq_lock_irqsave(rq, &rf);
+	update_rq_clock(rq);
+
+	llist_for_each_entry_safe(p, t, llist, wake_entry.llist) {
+		if (WARN_ON_ONCE(p->on_cpu))
+			smp_cond_load_acquire(&p->on_cpu, !VAL);
+
+		if (WARN_ON_ONCE(task_cpu(p) != cpu_of(rq)))
+			set_task_cpu(p, cpu_of(rq));
+
+		ttwu_do_activate(rq, p, p->sched_remote_wakeup ? WF_MIGRATED : 0, &rf);
+	}
+
+	rq_unlock_irqrestore(rq, &rf);
+}
+
+void send_call_function_single_ipi(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (!set_nr_if_polling(rq->idle))
+		arch_send_call_function_single_ipi(cpu);
+	else
+		trace_sched_wake_idle_without_ipi(cpu);
+}
+
+/*
+ * Queue a task on the target CPUs wake_list and wake the CPU via IPI if
+ * necessary. The wakee CPU on receipt of the IPI will queue the task
+ * via sched_ttwu_wakeup() for activation so the wakee incurs the cost
+ * of the wakeup instead of the waker.
+ */
+static void __ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED);
+
+	WRITE_ONCE(rq->ttwu_pending, 1);
+	__smp_call_single_queue(cpu, &p->wake_entry.llist);
+}
+
+void wake_up_if_idle(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+
+	rcu_read_lock();
+
+	if (!is_idle_task(rcu_dereference(rq->curr)))
+		goto out;
+
+	rq_lock_irqsave(rq, &rf);
+	if (is_idle_task(rq->curr))
+		resched_curr(rq);
+	/* Else CPU is not idle, do nothing here: */
+	rq_unlock_irqrestore(rq, &rf);
+
+out:
+	rcu_read_unlock();
+}
+
+bool cpus_share_cache(int this_cpu, int that_cpu)
+{
+	if (this_cpu == that_cpu)
+		return true;
+
+	return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
+}
+
+static inline bool ttwu_queue_cond(struct task_struct *p, int cpu)
+{
+	/*
+	 * Do not complicate things with the async wake_list while the CPU is
+	 * in hotplug state.
+	 */
+	if (!cpu_active(cpu))
+		return false;
+
+	/* Ensure the task will still be allowed to run on the CPU. */
+	if (!cpumask_test_cpu(cpu, p->cpus_ptr))
+		return false;
+
+	/*
+	 * If the CPU does not share cache, then queue the task on the
+	 * remote rqs wakelist to avoid accessing remote data.
+	 */
+	if (!cpus_share_cache(smp_processor_id(), cpu))
+		return true;
+
+	if (cpu == smp_processor_id())
+		return false;
+
+	/*
+	 * If the wakee cpu is idle, or the task is descheduling and the
+	 * only running task on the CPU, then use the wakelist to offload
+	 * the task activation to the idle (or soon-to-be-idle) CPU as
+	 * the current CPU is likely busy. nr_running is checked to
+	 * avoid unnecessary task stacking.
+	 *
+	 * Note that we can only get here with (wakee) p->on_rq=0,
+	 * p->on_cpu can be whatever, we've done the dequeue, so
+	 * the wakee has been accounted out of ->nr_running.
+	 */
+	if (!cpu_rq(cpu)->nr_running)
+		return true;
+
+	return false;
+}
+
+static bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
+{
+	if (sched_feat(TTWU_QUEUE) && ttwu_queue_cond(p, cpu)) {
+		sched_clock_cpu(cpu); /* Sync clocks across CPUs */
+		__ttwu_queue_wakelist(p, cpu, wake_flags);
+		return true;
+	}
+
+	return false;
+}
+
+#else /* !CONFIG_SMP */
+
+static inline bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
+{
+	return false;
+}
+
+#endif /* CONFIG_SMP */
+
+static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+
+	if (ttwu_queue_wakelist(p, cpu, wake_flags))
+		return;
+
+	rq_lock(rq, &rf);
+	update_rq_clock(rq);
+	ttwu_do_activate(rq, p, wake_flags, &rf);
+	rq_unlock(rq, &rf);
+}
+
+/*
+ * Invoked from try_to_wake_up() to check whether the task can be woken up.
+ *
+ * The caller holds p::pi_lock if p != current or has preemption
+ * disabled when p == current.
+ *
+ * The rules of PREEMPT_RT saved_state:
+ *
+ *   The related locking code always holds p::pi_lock when updating
+ *   p::saved_state, which means the code is fully serialized in both cases.
+ *
+ *   The lock wait and lock wakeups happen via TASK_RTLOCK_WAIT. No other
+ *   bits set. This allows to distinguish all wakeup scenarios.
+ */
+static __always_inline
+bool ttwu_state_match(struct task_struct *p, unsigned int state, int *success)
+{
+	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) {
+		WARN_ON_ONCE((state & TASK_RTLOCK_WAIT) &&
+			     state != TASK_RTLOCK_WAIT);
+	}
+
+	if (READ_ONCE(p->__state) & state) {
+		*success = 1;
+		return true;
+	}
+
+#ifdef CONFIG_PREEMPT_RT
+	/*
+	 * Saved state preserves the task state across blocking on
+	 * an RT lock.  If the state matches, set p::saved_state to
+	 * TASK_RUNNING, but do not wake the task because it waits
+	 * for a lock wakeup. Also indicate success because from
+	 * the regular waker's point of view this has succeeded.
+	 *
+	 * After acquiring the lock the task will restore p::__state
+	 * from p::saved_state which ensures that the regular
+	 * wakeup is not lost. The restore will also set
+	 * p::saved_state to TASK_RUNNING so any further tests will
+	 * not result in false positives vs. @success
+	 */
+	if (p->saved_state & state) {
+		p->saved_state = TASK_RUNNING;
+		*success = 1;
+	}
+#endif
+	return false;
+}
+
+/*
+ * Notes on Program-Order guarantees on SMP systems.
+ *
+ *  MIGRATION
+ *
+ * The basic program-order guarantee on SMP systems is that when a task [t]
+ * migrates, all its activity on its old CPU [c0] happens-before any subsequent
+ * execution on its new CPU [c1].
+ *
+ * For migration (of runnable tasks) this is provided by the following means:
+ *
+ *  A) UNLOCK of the rq(c0)->lock scheduling out task t
+ *  B) migration for t is required to synchronize *both* rq(c0)->lock and
+ *     rq(c1)->lock (if not at the same time, then in that order).
+ *  C) LOCK of the rq(c1)->lock scheduling in task
+ *
+ * Release/acquire chaining guarantees that B happens after A and C after B.
+ * Note: the CPU doing B need not be c0 or c1
+ *
+ * Example:
+ *
+ *   CPU0            CPU1            CPU2
+ *
+ *   LOCK rq(0)->lock
+ *   sched-out X
+ *   sched-in Y
+ *   UNLOCK rq(0)->lock
+ *
+ *                                   LOCK rq(0)->lock // orders against CPU0
+ *                                   dequeue X
+ *                                   UNLOCK rq(0)->lock
+ *
+ *                                   LOCK rq(1)->lock
+ *                                   enqueue X
+ *                                   UNLOCK rq(1)->lock
+ *
+ *                   LOCK rq(1)->lock // orders against CPU2
+ *                   sched-out Z
+ *                   sched-in X
+ *                   UNLOCK rq(1)->lock
+ *
+ *
+ *  BLOCKING -- aka. SLEEP + WAKEUP
+ *
+ * For blocking we (obviously) need to provide the same guarantee as for
+ * migration. However the means are completely different as there is no lock
+ * chain to provide order. Instead we do:
+ *
+ *   1) smp_store_release(X->on_cpu, 0)   -- finish_task()
+ *   2) smp_cond_load_acquire(!X->on_cpu) -- try_to_wake_up()
+ *
+ * Example:
+ *
+ *   CPU0 (schedule)  CPU1 (try_to_wake_up) CPU2 (schedule)
+ *
+ *   LOCK rq(0)->lock LOCK X->pi_lock
+ *   dequeue X
+ *   sched-out X
+ *   smp_store_release(X->on_cpu, 0);
+ *
+ *                    smp_cond_load_acquire(&X->on_cpu, !VAL);
+ *                    X->state = WAKING
+ *                    set_task_cpu(X,2)
+ *
+ *                    LOCK rq(2)->lock
+ *                    enqueue X
+ *                    X->state = RUNNING
+ *                    UNLOCK rq(2)->lock
+ *
+ *                                          LOCK rq(2)->lock // orders against CPU1
+ *                                          sched-out Z
+ *                                          sched-in X
+ *                                          UNLOCK rq(2)->lock
+ *
+ *                    UNLOCK X->pi_lock
+ *   UNLOCK rq(0)->lock
+ *
+ *
+ * However, for wakeups there is a second guarantee we must provide, namely we
+ * must ensure that CONDITION=1 done by the caller can not be reordered with
+ * accesses to the task state; see try_to_wake_up() and set_current_state().
+ */
+
+/**
+ * try_to_wake_up - wake up a thread
+ * @p: the thread to be awakened
+ * @state: the mask of task states that can be woken
+ * @wake_flags: wake modifier flags (WF_*)
+ *
+ * Conceptually does:
+ *
+ *   If (@state & @p->state) @p->state = TASK_RUNNING.
+ *
+ * If the task was not queued/runnable, also place it back on a runqueue.
+ *
+ * This function is atomic against schedule() which would dequeue the task.
+ *
+ * It issues a full memory barrier before accessing @p->state, see the comment
+ * with set_current_state().
+ *
+ * Uses p->pi_lock to serialize against concurrent wake-ups.
+ *
+ * Relies on p->pi_lock stabilizing:
+ *  - p->sched_class
+ *  - p->cpus_ptr
+ *  - p->sched_task_group
+ * in order to do migration, see its use of select_task_rq()/set_task_cpu().
+ *
+ * Tries really hard to only take one task_rq(p)->lock for performance.
+ * Takes rq->lock in:
+ *  - ttwu_runnable()    -- old rq, unavoidable, see comment there;
+ *  - ttwu_queue()       -- new rq, for enqueue of the task;
+ *  - psi_ttwu_dequeue() -- much sadness :-( accounting will kill us.
+ *
+ * As a consequence we race really badly with just about everything. See the
+ * many memory barriers and their comments for details.
+ *
+ * Return: %true if @p->state changes (an actual wakeup was done),
+ *	   %false otherwise.
+ */
+static int
+try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
+{
+	unsigned long flags;
+	int cpu, success = 0;
+
+	preempt_disable();
+	if (p == current) {
+		/*
+		 * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
+		 * == smp_processor_id()'. Together this means we can special
+		 * case the whole 'p->on_rq && ttwu_runnable()' case below
+		 * without taking any locks.
+		 *
+		 * In particular:
+		 *  - we rely on Program-Order guarantees for all the ordering,
+		 *  - we're serialized against set_special_state() by virtue of
+		 *    it disabling IRQs (this allows not taking ->pi_lock).
+		 */
+		if (!ttwu_state_match(p, state, &success))
+			goto out;
+
+		trace_sched_waking(p);
+		WRITE_ONCE(p->__state, TASK_RUNNING);
+		trace_sched_wakeup(p);
+		goto out;
+	}
+
+	/*
+	 * If we are going to wake up a thread waiting for CONDITION we
+	 * need to ensure that CONDITION=1 done by the caller can not be
+	 * reordered with p->state check below. This pairs with smp_store_mb()
+	 * in set_current_state() that the waiting thread does.
+	 */
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	smp_mb__after_spinlock();
+	if (!ttwu_state_match(p, state, &success))
+		goto unlock;
+
+	trace_sched_waking(p);
+
+	/*
+	 * Ensure we load p->on_rq _after_ p->state, otherwise it would
+	 * be possible to, falsely, observe p->on_rq == 0 and get stuck
+	 * in smp_cond_load_acquire() below.
+	 *
+	 * sched_ttwu_pending()			try_to_wake_up()
+	 *   STORE p->on_rq = 1			  LOAD p->state
+	 *   UNLOCK rq->lock
+	 *
+	 * __schedule() (switch to task 'p')
+	 *   LOCK rq->lock			  smp_rmb();
+	 *   smp_mb__after_spinlock();
+	 *   UNLOCK rq->lock
+	 *
+	 * [task p]
+	 *   STORE p->state = UNINTERRUPTIBLE	  LOAD p->on_rq
+	 *
+	 * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
+	 * __schedule().  See the comment for smp_mb__after_spinlock().
+	 *
+	 * A similar smb_rmb() lives in try_invoke_on_locked_down_task().
+	 */
+	smp_rmb();
+	if (READ_ONCE(p->on_rq) && ttwu_runnable(p, wake_flags))
+		goto unlock;
+
+#ifdef CONFIG_SMP
+	/*
+	 * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be
+	 * possible to, falsely, observe p->on_cpu == 0.
+	 *
+	 * One must be running (->on_cpu == 1) in order to remove oneself
+	 * from the runqueue.
+	 *
+	 * __schedule() (switch to task 'p')	try_to_wake_up()
+	 *   STORE p->on_cpu = 1		  LOAD p->on_rq
+	 *   UNLOCK rq->lock
+	 *
+	 * __schedule() (put 'p' to sleep)
+	 *   LOCK rq->lock			  smp_rmb();
+	 *   smp_mb__after_spinlock();
+	 *   STORE p->on_rq = 0			  LOAD p->on_cpu
+	 *
+	 * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
+	 * __schedule().  See the comment for smp_mb__after_spinlock().
+	 *
+	 * Form a control-dep-acquire with p->on_rq == 0 above, to ensure
+	 * schedule()'s deactivate_task() has 'happened' and p will no longer
+	 * care about it's own p->state. See the comment in __schedule().
+	 */
+	smp_acquire__after_ctrl_dep();
+
+	/*
+	 * We're doing the wakeup (@success == 1), they did a dequeue (p->on_rq
+	 * == 0), which means we need to do an enqueue, change p->state to
+	 * TASK_WAKING such that we can unlock p->pi_lock before doing the
+	 * enqueue, such as ttwu_queue_wakelist().
+	 */
+	WRITE_ONCE(p->__state, TASK_WAKING);
+
+	/*
+	 * If the owning (remote) CPU is still in the middle of schedule() with
+	 * this task as prev, considering queueing p on the remote CPUs wake_list
+	 * which potentially sends an IPI instead of spinning on p->on_cpu to
+	 * let the waker make forward progress. This is safe because IRQs are
+	 * disabled and the IPI will deliver after on_cpu is cleared.
+	 *
+	 * Ensure we load task_cpu(p) after p->on_cpu:
+	 *
+	 * set_task_cpu(p, cpu);
+	 *   STORE p->cpu = @cpu
+	 * __schedule() (switch to task 'p')
+	 *   LOCK rq->lock
+	 *   smp_mb__after_spin_lock()		smp_cond_load_acquire(&p->on_cpu)
+	 *   STORE p->on_cpu = 1		LOAD p->cpu
+	 *
+	 * to ensure we observe the correct CPU on which the task is currently
+	 * scheduling.
+	 */
+	if (smp_load_acquire(&p->on_cpu) &&
+	    ttwu_queue_wakelist(p, task_cpu(p), wake_flags))
+		goto unlock;
+
+	/*
+	 * If the owning (remote) CPU is still in the middle of schedule() with
+	 * this task as prev, wait until it's done referencing the task.
+	 *
+	 * Pairs with the smp_store_release() in finish_task().
+	 *
+	 * This ensures that tasks getting woken will be fully ordered against
+	 * their previous state and preserve Program Order.
+	 */
+	smp_cond_load_acquire(&p->on_cpu, !VAL);
+
+	cpu = select_task_rq(p, p->wake_cpu, wake_flags | WF_TTWU);
+	if (task_cpu(p) != cpu) {
+		if (p->in_iowait) {
+			delayacct_blkio_end(p);
+			atomic_dec(&task_rq(p)->nr_iowait);
+		}
+
+		wake_flags |= WF_MIGRATED;
+		psi_ttwu_dequeue(p);
+		set_task_cpu(p, cpu);
+	}
+#else
+	cpu = task_cpu(p);
+#endif /* CONFIG_SMP */
+
+	ttwu_queue(p, cpu, wake_flags);
+unlock:
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+out:
+	if (success)
+		ttwu_stat(p, task_cpu(p), wake_flags);
+	preempt_enable();
+
+	return success;
+}
+
+static bool __task_needs_rq_lock(struct task_struct *p)
+{
+	unsigned int state = READ_ONCE(p->__state);
+
+	/*
+	 * Since pi->lock blocks try_to_wake_up(), we don't need rq->lock when
+	 * the task is blocked. Make sure to check @state since ttwu() can drop
+	 * locks at the end, see ttwu_queue_wakelist().
+	 */
+	if (state == TASK_RUNNING || state == TASK_WAKING)
+		return true;
+
+	/*
+	 * Ensure we load p->on_rq after p->__state, otherwise it would be
+	 * possible to, falsely, observe p->on_rq == 0.
+	 *
+	 * See try_to_wake_up() for a longer comment.
+	 */
+	smp_rmb();
+	if (p->on_rq)
+		return true;
+
+#ifdef CONFIG_SMP
+	/*
+	 * Ensure the task has finished __schedule() and will not be referenced
+	 * anymore. Again, see try_to_wake_up() for a longer comment.
+	 */
+	smp_rmb();
+	smp_cond_load_acquire(&p->on_cpu, !VAL);
+#endif
+
+	return false;
+}
+
+/**
+ * task_call_func - Invoke a function on task in fixed state
+ * @p: Process for which the function is to be invoked, can be @current.
+ * @func: Function to invoke.
+ * @arg: Argument to function.
+ *
+ * Fix the task in it's current state by avoiding wakeups and or rq operations
+ * and call @func(@arg) on it.  This function can use ->on_rq and task_curr()
+ * to work out what the state is, if required.  Given that @func can be invoked
+ * with a runqueue lock held, it had better be quite lightweight.
+ *
+ * Returns:
+ *   Whatever @func returns
+ */
+int task_call_func(struct task_struct *p, task_call_f func, void *arg)
+{
+	struct rq *rq = NULL;
+	struct rq_flags rf;
+	int ret;
+
+	raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
+
+	if (__task_needs_rq_lock(p))
+		rq = __task_rq_lock(p, &rf);
+
+	/*
+	 * At this point the task is pinned; either:
+	 *  - blocked and we're holding off wakeups	 (pi->lock)
+	 *  - woken, and we're holding off enqueue	 (rq->lock)
+	 *  - queued, and we're holding off schedule	 (rq->lock)
+	 *  - running, and we're holding off de-schedule (rq->lock)
+	 *
+	 * The called function (@func) can use: task_curr(), p->on_rq and
+	 * p->__state to differentiate between these states.
+	 */
+	ret = func(p, arg);
+
+	if (rq)
+		rq_unlock(rq, &rf);
+
+	raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags);
+	return ret;
+}
+
+/**
+ * cpu_curr_snapshot - Return a snapshot of the currently running task
+ * @cpu: The CPU on which to snapshot the task.
+ *
+ * Returns the task_struct pointer of the task "currently" running on
+ * the specified CPU.  If the same task is running on that CPU throughout,
+ * the return value will be a pointer to that task's task_struct structure.
+ * If the CPU did any context switches even vaguely concurrently with the
+ * execution of this function, the return value will be a pointer to the
+ * task_struct structure of a randomly chosen task that was running on
+ * that CPU somewhere around the time that this function was executing.
+ *
+ * If the specified CPU was offline, the return value is whatever it
+ * is, perhaps a pointer to the task_struct structure of that CPU's idle
+ * task, but there is no guarantee.  Callers wishing a useful return
+ * value must take some action to ensure that the specified CPU remains
+ * online throughout.
+ *
+ * This function executes full memory barriers before and after fetching
+ * the pointer, which permits the caller to confine this function's fetch
+ * with respect to the caller's accesses to other shared variables.
+ */
+struct task_struct *cpu_curr_snapshot(int cpu)
+{
+	struct task_struct *t;
+
+	smp_mb(); /* Pairing determined by caller's synchronization design. */
+	t = rcu_dereference(cpu_curr(cpu));
+	smp_mb(); /* Pairing determined by caller's synchronization design. */
+	return t;
+}
+
+/**
+ * wake_up_process - Wake up a specific process
+ * @p: The process to be woken up.
+ *
+ * Attempt to wake up the nominated process and move it to the set of runnable
+ * processes.
+ *
+ * Return: 1 if the process was woken up, 0 if it was already running.
+ *
+ * This function executes a full memory barrier before accessing the task state.
+ */
+int wake_up_process(struct task_struct *p)
+{
+	return try_to_wake_up(p, TASK_NORMAL, 0);
+}
+EXPORT_SYMBOL(wake_up_process);
+
+int wake_up_state(struct task_struct *p, unsigned int state)
+{
+	return try_to_wake_up(p, state, 0);
+}
+
+/*
+ * Perform scheduler related setup for a newly forked process p.
+ * p is forked by current.
+ *
+ * __sched_fork() is basic setup used by init_idle() too:
+ */
+static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
+{
+	p->on_rq			= 0;
+
+	p->se.on_rq			= 0;
+	p->se.exec_start		= 0;
+	p->se.sum_exec_runtime		= 0;
+	p->se.prev_sum_exec_runtime	= 0;
+	p->se.nr_migrations		= 0;
+	p->se.vruntime			= 0;
+	INIT_LIST_HEAD(&p->se.group_node);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	p->se.cfs_rq			= NULL;
+#endif
+
+#ifdef CONFIG_SCHEDSTATS
+	/* Even if schedstat is disabled, there should not be garbage */
+	memset(&p->stats, 0, sizeof(p->stats));
+#endif
+
+	RB_CLEAR_NODE(&p->dl.rb_node);
+	init_dl_task_timer(&p->dl);
+	init_dl_inactive_task_timer(&p->dl);
+	__dl_clear_params(p);
+
+	INIT_LIST_HEAD(&p->rt.run_list);
+	p->rt.timeout		= 0;
+	p->rt.time_slice	= sched_rr_timeslice;
+	p->rt.on_rq		= 0;
+	p->rt.on_list		= 0;
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+	INIT_HLIST_HEAD(&p->preempt_notifiers);
+#endif
+
+#ifdef CONFIG_COMPACTION
+	p->capture_control = NULL;
+#endif
+	init_numa_balancing(clone_flags, p);
+#ifdef CONFIG_SMP
+	p->wake_entry.u_flags = CSD_TYPE_TTWU;
+	p->migration_pending = NULL;
+#endif
+}
+
+DEFINE_STATIC_KEY_FALSE(sched_numa_balancing);
+
+#ifdef CONFIG_NUMA_BALANCING
+
+int sysctl_numa_balancing_mode;
+
+static void __set_numabalancing_state(bool enabled)
+{
+	if (enabled)
+		static_branch_enable(&sched_numa_balancing);
+	else
+		static_branch_disable(&sched_numa_balancing);
+}
+
+void set_numabalancing_state(bool enabled)
+{
+	if (enabled)
+		sysctl_numa_balancing_mode = NUMA_BALANCING_NORMAL;
+	else
+		sysctl_numa_balancing_mode = NUMA_BALANCING_DISABLED;
+	__set_numabalancing_state(enabled);
+}
+
+#ifdef CONFIG_PROC_SYSCTL
+static void reset_memory_tiering(void)
+{
+	struct pglist_data *pgdat;
+
+	for_each_online_pgdat(pgdat) {
+		pgdat->nbp_threshold = 0;
+		pgdat->nbp_th_nr_cand = node_page_state(pgdat, PGPROMOTE_CANDIDATE);
+		pgdat->nbp_th_start = jiffies_to_msecs(jiffies);
+	}
+}
+
+int sysctl_numa_balancing(struct ctl_table *table, int write,
+			  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table t;
+	int err;
+	int state = sysctl_numa_balancing_mode;
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	t = *table;
+	t.data = &state;
+	err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
+	if (err < 0)
+		return err;
+	if (write) {
+		if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) &&
+		    (state & NUMA_BALANCING_MEMORY_TIERING))
+			reset_memory_tiering();
+		sysctl_numa_balancing_mode = state;
+		__set_numabalancing_state(state);
+	}
+	return err;
+}
+#endif
+#endif
+
+#ifdef CONFIG_SCHEDSTATS
+
+DEFINE_STATIC_KEY_FALSE(sched_schedstats);
+
+static void set_schedstats(bool enabled)
+{
+	if (enabled)
+		static_branch_enable(&sched_schedstats);
+	else
+		static_branch_disable(&sched_schedstats);
+}
+
+void force_schedstat_enabled(void)
+{
+	if (!schedstat_enabled()) {
+		pr_info("kernel profiling enabled schedstats, disable via kernel.sched_schedstats.\n");
+		static_branch_enable(&sched_schedstats);
+	}
+}
+
+static int __init setup_schedstats(char *str)
+{
+	int ret = 0;
+	if (!str)
+		goto out;
+
+	if (!strcmp(str, "enable")) {
+		set_schedstats(true);
+		ret = 1;
+	} else if (!strcmp(str, "disable")) {
+		set_schedstats(false);
+		ret = 1;
+	}
+out:
+	if (!ret)
+		pr_warn("Unable to parse schedstats=\n");
+
+	return ret;
+}
+__setup("schedstats=", setup_schedstats);
+
+#ifdef CONFIG_PROC_SYSCTL
+static int sysctl_schedstats(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table t;
+	int err;
+	int state = static_branch_likely(&sched_schedstats);
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	t = *table;
+	t.data = &state;
+	err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
+	if (err < 0)
+		return err;
+	if (write)
+		set_schedstats(state);
+	return err;
+}
+#endif /* CONFIG_PROC_SYSCTL */
+#endif /* CONFIG_SCHEDSTATS */
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table sched_core_sysctls[] = {
+#ifdef CONFIG_SCHEDSTATS
+	{
+		.procname       = "sched_schedstats",
+		.data           = NULL,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sysctl_schedstats,
+		.extra1         = SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE,
+	},
+#endif /* CONFIG_SCHEDSTATS */
+#ifdef CONFIG_UCLAMP_TASK
+	{
+		.procname       = "sched_util_clamp_min",
+		.data           = &sysctl_sched_uclamp_util_min,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sysctl_sched_uclamp_handler,
+	},
+	{
+		.procname       = "sched_util_clamp_max",
+		.data           = &sysctl_sched_uclamp_util_max,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sysctl_sched_uclamp_handler,
+	},
+	{
+		.procname       = "sched_util_clamp_min_rt_default",
+		.data           = &sysctl_sched_uclamp_util_min_rt_default,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sysctl_sched_uclamp_handler,
+	},
+#endif /* CONFIG_UCLAMP_TASK */
+	{}
+};
+static int __init sched_core_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_core_sysctls);
+	return 0;
+}
+late_initcall(sched_core_sysctl_init);
+#endif /* CONFIG_SYSCTL */
+
+/*
+ * fork()/clone()-time setup:
+ */
+int sched_fork(unsigned long clone_flags, struct task_struct *p)
+{
+	__sched_fork(clone_flags, p);
+	/*
+	 * We mark the process as NEW here. This guarantees that
+	 * nobody will actually run it, and a signal or other external
+	 * event cannot wake it up and insert it on the runqueue either.
+	 */
+	p->__state = TASK_NEW;
+
+	/*
+	 * Make sure we do not leak PI boosting priority to the child.
+	 */
+	p->prio = current->normal_prio;
+
+	uclamp_fork(p);
+
+	/*
+	 * Revert to default priority/policy on fork if requested.
+	 */
+	if (unlikely(p->sched_reset_on_fork)) {
+		if (task_has_dl_policy(p) || task_has_rt_policy(p)) {
+			p->policy = SCHED_NORMAL;
+			p->static_prio = NICE_TO_PRIO(0);
+			p->rt_priority = 0;
+		} else if (PRIO_TO_NICE(p->static_prio) < 0)
+			p->static_prio = NICE_TO_PRIO(0);
+
+		p->prio = p->normal_prio = p->static_prio;
+		set_load_weight(p, false);
+
+		/*
+		 * We don't need the reset flag anymore after the fork. It has
+		 * fulfilled its duty:
+		 */
+		p->sched_reset_on_fork = 0;
+	}
+
+	if (dl_prio(p->prio))
+		return -EAGAIN;
+	else if (rt_prio(p->prio))
+		p->sched_class = &rt_sched_class;
+	else
+		p->sched_class = &fair_sched_class;
+
+	init_entity_runnable_average(&p->se);
+
+
+#ifdef CONFIG_SCHED_INFO
+	if (likely(sched_info_on()))
+		memset(&p->sched_info, 0, sizeof(p->sched_info));
+#endif
+#if defined(CONFIG_SMP)
+	p->on_cpu = 0;
+#endif
+	init_task_preempt_count(p);
+#ifdef CONFIG_SMP
+	plist_node_init(&p->pushable_tasks, MAX_PRIO);
+	RB_CLEAR_NODE(&p->pushable_dl_tasks);
+#endif
+	return 0;
+}
+
+void sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs)
+{
+	unsigned long flags;
+
+	/*
+	 * Because we're not yet on the pid-hash, p->pi_lock isn't strictly
+	 * required yet, but lockdep gets upset if rules are violated.
+	 */
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+#ifdef CONFIG_CGROUP_SCHED
+	if (1) {
+		struct task_group *tg;
+		tg = container_of(kargs->cset->subsys[cpu_cgrp_id],
+				  struct task_group, css);
+		tg = autogroup_task_group(p, tg);
+		p->sched_task_group = tg;
+	}
+#endif
+	rseq_migrate(p);
+	/*
+	 * We're setting the CPU for the first time, we don't migrate,
+	 * so use __set_task_cpu().
+	 */
+	__set_task_cpu(p, smp_processor_id());
+	if (p->sched_class->task_fork)
+		p->sched_class->task_fork(p);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+}
+
+void sched_post_fork(struct task_struct *p)
+{
+	uclamp_post_fork(p);
+}
+
+unsigned long to_ratio(u64 period, u64 runtime)
+{
+	if (runtime == RUNTIME_INF)
+		return BW_UNIT;
+
+	/*
+	 * Doing this here saves a lot of checks in all
+	 * the calling paths, and returning zero seems
+	 * safe for them anyway.
+	 */
+	if (period == 0)
+		return 0;
+
+	return div64_u64(runtime << BW_SHIFT, period);
+}
+
+/*
+ * wake_up_new_task - wake up a newly created task for the first time.
+ *
+ * This function will do some initial scheduler statistics housekeeping
+ * that must be done for every newly created context, then puts the task
+ * on the runqueue and wakes it.
+ */
+void wake_up_new_task(struct task_struct *p)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
+	WRITE_ONCE(p->__state, TASK_RUNNING);
+#ifdef CONFIG_SMP
+	/*
+	 * Fork balancing, do it here and not earlier because:
+	 *  - cpus_ptr can change in the fork path
+	 *  - any previously selected CPU might disappear through hotplug
+	 *
+	 * Use __set_task_cpu() to avoid calling sched_class::migrate_task_rq,
+	 * as we're not fully set-up yet.
+	 */
+	p->recent_used_cpu = task_cpu(p);
+	rseq_migrate(p);
+	__set_task_cpu(p, select_task_rq(p, task_cpu(p), WF_FORK));
+#endif
+	rq = __task_rq_lock(p, &rf);
+	update_rq_clock(rq);
+	post_init_entity_util_avg(p);
+
+	activate_task(rq, p, ENQUEUE_NOCLOCK);
+	trace_sched_wakeup_new(p);
+	check_preempt_curr(rq, p, WF_FORK);
+#ifdef CONFIG_SMP
+	if (p->sched_class->task_woken) {
+		/*
+		 * Nothing relies on rq->lock after this, so it's fine to
+		 * drop it.
+		 */
+		rq_unpin_lock(rq, &rf);
+		p->sched_class->task_woken(rq, p);
+		rq_repin_lock(rq, &rf);
+	}
+#endif
+	task_rq_unlock(rq, p, &rf);
+}
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+
+static DEFINE_STATIC_KEY_FALSE(preempt_notifier_key);
+
+void preempt_notifier_inc(void)
+{
+	static_branch_inc(&preempt_notifier_key);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_inc);
+
+void preempt_notifier_dec(void)
+{
+	static_branch_dec(&preempt_notifier_key);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_dec);
+
+/**
+ * preempt_notifier_register - tell me when current is being preempted & rescheduled
+ * @notifier: notifier struct to register
+ */
+void preempt_notifier_register(struct preempt_notifier *notifier)
+{
+	if (!static_branch_unlikely(&preempt_notifier_key))
+		WARN(1, "registering preempt_notifier while notifiers disabled\n");
+
+	hlist_add_head(&notifier->link, &current->preempt_notifiers);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_register);
+
+/**
+ * preempt_notifier_unregister - no longer interested in preemption notifications
+ * @notifier: notifier struct to unregister
+ *
+ * This is *not* safe to call from within a preemption notifier.
+ */
+void preempt_notifier_unregister(struct preempt_notifier *notifier)
+{
+	hlist_del(&notifier->link);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
+
+static void __fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+	struct preempt_notifier *notifier;
+
+	hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
+		notifier->ops->sched_in(notifier, raw_smp_processor_id());
+}
+
+static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+	if (static_branch_unlikely(&preempt_notifier_key))
+		__fire_sched_in_preempt_notifiers(curr);
+}
+
+static void
+__fire_sched_out_preempt_notifiers(struct task_struct *curr,
+				   struct task_struct *next)
+{
+	struct preempt_notifier *notifier;
+
+	hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
+		notifier->ops->sched_out(notifier, next);
+}
+
+static __always_inline void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+				 struct task_struct *next)
+{
+	if (static_branch_unlikely(&preempt_notifier_key))
+		__fire_sched_out_preempt_notifiers(curr, next);
+}
+
+#else /* !CONFIG_PREEMPT_NOTIFIERS */
+
+static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+}
+
+static inline void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+				 struct task_struct *next)
+{
+}
+
+#endif /* CONFIG_PREEMPT_NOTIFIERS */
+
+static inline void prepare_task(struct task_struct *next)
+{
+#ifdef CONFIG_SMP
+	/*
+	 * Claim the task as running, we do this before switching to it
+	 * such that any running task will have this set.
+	 *
+	 * See the smp_load_acquire(&p->on_cpu) case in ttwu() and
+	 * its ordering comment.
+	 */
+	WRITE_ONCE(next->on_cpu, 1);
+#endif
+}
+
+static inline void finish_task(struct task_struct *prev)
+{
+#ifdef CONFIG_SMP
+	/*
+	 * This must be the very last reference to @prev from this CPU. After
+	 * p->on_cpu is cleared, the task can be moved to a different CPU. We
+	 * must ensure this doesn't happen until the switch is completely
+	 * finished.
+	 *
+	 * In particular, the load of prev->state in finish_task_switch() must
+	 * happen before this.
+	 *
+	 * Pairs with the smp_cond_load_acquire() in try_to_wake_up().
+	 */
+	smp_store_release(&prev->on_cpu, 0);
+#endif
+}
+
+#ifdef CONFIG_SMP
+
+static void do_balance_callbacks(struct rq *rq, struct balance_callback *head)
+{
+	void (*func)(struct rq *rq);
+	struct balance_callback *next;
+
+	lockdep_assert_rq_held(rq);
+
+	while (head) {
+		func = (void (*)(struct rq *))head->func;
+		next = head->next;
+		head->next = NULL;
+		head = next;
+
+		func(rq);
+	}
+}
+
+static void balance_push(struct rq *rq);
+
+/*
+ * balance_push_callback is a right abuse of the callback interface and plays
+ * by significantly different rules.
+ *
+ * Where the normal balance_callback's purpose is to be ran in the same context
+ * that queued it (only later, when it's safe to drop rq->lock again),
+ * balance_push_callback is specifically targeted at __schedule().
+ *
+ * This abuse is tolerated because it places all the unlikely/odd cases behind
+ * a single test, namely: rq->balance_callback == NULL.
+ */
+struct balance_callback balance_push_callback = {
+	.next = NULL,
+	.func = balance_push,
+};
+
+static inline struct balance_callback *
+__splice_balance_callbacks(struct rq *rq, bool split)
+{
+	struct balance_callback *head = rq->balance_callback;
+
+	if (likely(!head))
+		return NULL;
+
+	lockdep_assert_rq_held(rq);
+	/*
+	 * Must not take balance_push_callback off the list when
+	 * splice_balance_callbacks() and balance_callbacks() are not
+	 * in the same rq->lock section.
+	 *
+	 * In that case it would be possible for __schedule() to interleave
+	 * and observe the list empty.
+	 */
+	if (split && head == &balance_push_callback)
+		head = NULL;
+	else
+		rq->balance_callback = NULL;
+
+	return head;
+}
+
+static inline struct balance_callback *splice_balance_callbacks(struct rq *rq)
+{
+	return __splice_balance_callbacks(rq, true);
+}
+
+static void __balance_callbacks(struct rq *rq)
+{
+	do_balance_callbacks(rq, __splice_balance_callbacks(rq, false));
+}
+
+static inline void balance_callbacks(struct rq *rq, struct balance_callback *head)
+{
+	unsigned long flags;
+
+	if (unlikely(head)) {
+		raw_spin_rq_lock_irqsave(rq, flags);
+		do_balance_callbacks(rq, head);
+		raw_spin_rq_unlock_irqrestore(rq, flags);
+	}
+}
+
+#else
+
+static inline void __balance_callbacks(struct rq *rq)
+{
+}
+
+static inline struct balance_callback *splice_balance_callbacks(struct rq *rq)
+{
+	return NULL;
+}
+
+static inline void balance_callbacks(struct rq *rq, struct balance_callback *head)
+{
+}
+
+#endif
+
+static inline void
+prepare_lock_switch(struct rq *rq, struct task_struct *next, struct rq_flags *rf)
+{
+	/*
+	 * Since the runqueue lock will be released by the next
+	 * task (which is an invalid locking op but in the case
+	 * of the scheduler it's an obvious special-case), so we
+	 * do an early lockdep release here:
+	 */
+	rq_unpin_lock(rq, rf);
+	spin_release(&__rq_lockp(rq)->dep_map, _THIS_IP_);
+#ifdef CONFIG_DEBUG_SPINLOCK
+	/* this is a valid case when another task releases the spinlock */
+	rq_lockp(rq)->owner = next;
+#endif
+}
+
+static inline void finish_lock_switch(struct rq *rq)
+{
+	/*
+	 * If we are tracking spinlock dependencies then we have to
+	 * fix up the runqueue lock - which gets 'carried over' from
+	 * prev into current:
+	 */
+	spin_acquire(&__rq_lockp(rq)->dep_map, 0, 0, _THIS_IP_);
+	__balance_callbacks(rq);
+	raw_spin_rq_unlock_irq(rq);
+}
+
+/*
+ * NOP if the arch has not defined these:
+ */
+
+#ifndef prepare_arch_switch
+# define prepare_arch_switch(next)	do { } while (0)
+#endif
+
+#ifndef finish_arch_post_lock_switch
+# define finish_arch_post_lock_switch()	do { } while (0)
+#endif
+
+static inline void kmap_local_sched_out(void)
+{
+#ifdef CONFIG_KMAP_LOCAL
+	if (unlikely(current->kmap_ctrl.idx))
+		__kmap_local_sched_out();
+#endif
+}
+
+static inline void kmap_local_sched_in(void)
+{
+#ifdef CONFIG_KMAP_LOCAL
+	if (unlikely(current->kmap_ctrl.idx))
+		__kmap_local_sched_in();
+#endif
+}
+
+/**
+ * prepare_task_switch - prepare to switch tasks
+ * @rq: the runqueue preparing to switch
+ * @prev: the current task that is being switched out
+ * @next: the task we are going to switch to.
+ *
+ * This is called with the rq lock held and interrupts off. It must
+ * be paired with a subsequent finish_task_switch after the context
+ * switch.
+ *
+ * prepare_task_switch sets up locking and calls architecture specific
+ * hooks.
+ */
+static inline void
+prepare_task_switch(struct rq *rq, struct task_struct *prev,
+		    struct task_struct *next)
+{
+	kcov_prepare_switch(prev);
+	sched_info_switch(rq, prev, next);
+	perf_event_task_sched_out(prev, next);
+	rseq_preempt(prev);
+	fire_sched_out_preempt_notifiers(prev, next);
+	kmap_local_sched_out();
+	prepare_task(next);
+	prepare_arch_switch(next);
+}
+
+/**
+ * finish_task_switch - clean up after a task-switch
+ * @prev: the thread we just switched away from.
+ *
+ * finish_task_switch must be called after the context switch, paired
+ * with a prepare_task_switch call before the context switch.
+ * finish_task_switch will reconcile locking set up by prepare_task_switch,
+ * and do any other architecture-specific cleanup actions.
+ *
+ * Note that we may have delayed dropping an mm in context_switch(). If
+ * so, we finish that here outside of the runqueue lock. (Doing it
+ * with the lock held can cause deadlocks; see schedule() for
+ * details.)
+ *
+ * The context switch have flipped the stack from under us and restored the
+ * local variables which were saved when this task called schedule() in the
+ * past. prev == current is still correct but we need to recalculate this_rq
+ * because prev may have moved to another CPU.
+ */
+static struct rq *finish_task_switch(struct task_struct *prev)
+	__releases(rq->lock)
+{
+	struct rq *rq = this_rq();
+	struct mm_struct *mm = rq->prev_mm;
+	unsigned int prev_state;
+
+	/*
+	 * The previous task will have left us with a preempt_count of 2
+	 * because it left us after:
+	 *
+	 *	schedule()
+	 *	  preempt_disable();			// 1
+	 *	  __schedule()
+	 *	    raw_spin_lock_irq(&rq->lock)	// 2
+	 *
+	 * Also, see FORK_PREEMPT_COUNT.
+	 */
+	if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET,
+		      "corrupted preempt_count: %s/%d/0x%x\n",
+		      current->comm, current->pid, preempt_count()))
+		preempt_count_set(FORK_PREEMPT_COUNT);
+
+	rq->prev_mm = NULL;
+
+	/*
+	 * A task struct has one reference for the use as "current".
+	 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
+	 * schedule one last time. The schedule call will never return, and
+	 * the scheduled task must drop that reference.
+	 *
+	 * We must observe prev->state before clearing prev->on_cpu (in
+	 * finish_task), otherwise a concurrent wakeup can get prev
+	 * running on another CPU and we could rave with its RUNNING -> DEAD
+	 * transition, resulting in a double drop.
+	 */
+	prev_state = READ_ONCE(prev->__state);
+	vtime_task_switch(prev);
+	perf_event_task_sched_in(prev, current);
+	finish_task(prev);
+	tick_nohz_task_switch();
+	finish_lock_switch(rq);
+	finish_arch_post_lock_switch();
+	kcov_finish_switch(current);
+	/*
+	 * kmap_local_sched_out() is invoked with rq::lock held and
+	 * interrupts disabled. There is no requirement for that, but the
+	 * sched out code does not have an interrupt enabled section.
+	 * Restoring the maps on sched in does not require interrupts being
+	 * disabled either.
+	 */
+	kmap_local_sched_in();
+
+	fire_sched_in_preempt_notifiers(current);
+	/*
+	 * When switching through a kernel thread, the loop in
+	 * membarrier_{private,global}_expedited() may have observed that
+	 * kernel thread and not issued an IPI. It is therefore possible to
+	 * schedule between user->kernel->user threads without passing though
+	 * switch_mm(). Membarrier requires a barrier after storing to
+	 * rq->curr, before returning to userspace, so provide them here:
+	 *
+	 * - a full memory barrier for {PRIVATE,GLOBAL}_EXPEDITED, implicitly
+	 *   provided by mmdrop(),
+	 * - a sync_core for SYNC_CORE.
+	 */
+	if (mm) {
+		membarrier_mm_sync_core_before_usermode(mm);
+		mmdrop_sched(mm);
+	}
+	if (unlikely(prev_state == TASK_DEAD)) {
+		if (prev->sched_class->task_dead)
+			prev->sched_class->task_dead(prev);
+
+		/* Task is done with its stack. */
+		put_task_stack(prev);
+
+		put_task_struct_rcu_user(prev);
+	}
+
+	return rq;
+}
+
+/**
+ * schedule_tail - first thing a freshly forked thread must call.
+ * @prev: the thread we just switched away from.
+ */
+asmlinkage __visible void schedule_tail(struct task_struct *prev)
+	__releases(rq->lock)
+{
+	/*
+	 * New tasks start with FORK_PREEMPT_COUNT, see there and
+	 * finish_task_switch() for details.
+	 *
+	 * finish_task_switch() will drop rq->lock() and lower preempt_count
+	 * and the preempt_enable() will end up enabling preemption (on
+	 * PREEMPT_COUNT kernels).
+	 */
+
+	finish_task_switch(prev);
+	preempt_enable();
+
+	if (current->set_child_tid)
+		put_user(task_pid_vnr(current), current->set_child_tid);
+
+	calculate_sigpending();
+}
+
+/*
+ * context_switch - switch to the new MM and the new thread's register state.
+ */
+static __always_inline struct rq *
+context_switch(struct rq *rq, struct task_struct *prev,
+	       struct task_struct *next, struct rq_flags *rf)
+{
+	prepare_task_switch(rq, prev, next);
+
+	/*
+	 * For paravirt, this is coupled with an exit in switch_to to
+	 * combine the page table reload and the switch backend into
+	 * one hypercall.
+	 */
+	arch_start_context_switch(prev);
+
+	/*
+	 * kernel -> kernel   lazy + transfer active
+	 *   user -> kernel   lazy + mmgrab() active
+	 *
+	 * kernel ->   user   switch + mmdrop() active
+	 *   user ->   user   switch
+	 */
+	if (!next->mm) {                                // to kernel
+		enter_lazy_tlb(prev->active_mm, next);
+
+		next->active_mm = prev->active_mm;
+		if (prev->mm)                           // from user
+			mmgrab(prev->active_mm);
+		else
+			prev->active_mm = NULL;
+	} else {                                        // to user
+		membarrier_switch_mm(rq, prev->active_mm, next->mm);
+		/*
+		 * sys_membarrier() requires an smp_mb() between setting
+		 * rq->curr / membarrier_switch_mm() and returning to userspace.
+		 *
+		 * The below provides this either through switch_mm(), or in
+		 * case 'prev->active_mm == next->mm' through
+		 * finish_task_switch()'s mmdrop().
+		 */
+		switch_mm_irqs_off(prev->active_mm, next->mm, next);
+		lru_gen_use_mm(next->mm);
+
+		if (!prev->mm) {                        // from kernel
+			/* will mmdrop() in finish_task_switch(). */
+			rq->prev_mm = prev->active_mm;
+			prev->active_mm = NULL;
+		}
+	}
+
+	rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP);
+
+	prepare_lock_switch(rq, next, rf);
+
+	/* Here we just switch the register state and the stack. */
+	switch_to(prev, next, prev);
+	barrier();
+
+	return finish_task_switch(prev);
+}
+
+/*
+ * nr_running and nr_context_switches:
+ *
+ * externally visible scheduler statistics: current number of runnable
+ * threads, total number of context switches performed since bootup.
+ */
+unsigned int nr_running(void)
+{
+	unsigned int i, sum = 0;
+
+	for_each_online_cpu(i)
+		sum += cpu_rq(i)->nr_running;
+
+	return sum;
+}
+
+/*
+ * Check if only the current task is running on the CPU.
+ *
+ * Caution: this function does not check that the caller has disabled
+ * preemption, thus the result might have a time-of-check-to-time-of-use
+ * race.  The caller is responsible to use it correctly, for example:
+ *
+ * - from a non-preemptible section (of course)
+ *
+ * - from a thread that is bound to a single CPU
+ *
+ * - in a loop with very short iterations (e.g. a polling loop)
+ */
+bool single_task_running(void)
+{
+	return raw_rq()->nr_running == 1;
+}
+EXPORT_SYMBOL(single_task_running);
+
+unsigned long long nr_context_switches(void)
+{
+	int i;
+	unsigned long long sum = 0;
+
+	for_each_possible_cpu(i)
+		sum += cpu_rq(i)->nr_switches;
+
+	return sum;
+}
+
+/*
+ * Consumers of these two interfaces, like for example the cpuidle menu
+ * governor, are using nonsensical data. Preferring shallow idle state selection
+ * for a CPU that has IO-wait which might not even end up running the task when
+ * it does become runnable.
+ */
+
+unsigned int nr_iowait_cpu(int cpu)
+{
+	return atomic_read(&cpu_rq(cpu)->nr_iowait);
+}
+
+/*
+ * IO-wait accounting, and how it's mostly bollocks (on SMP).
+ *
+ * The idea behind IO-wait account is to account the idle time that we could
+ * have spend running if it were not for IO. That is, if we were to improve the
+ * storage performance, we'd have a proportional reduction in IO-wait time.
+ *
+ * This all works nicely on UP, where, when a task blocks on IO, we account
+ * idle time as IO-wait, because if the storage were faster, it could've been
+ * running and we'd not be idle.
+ *
+ * This has been extended to SMP, by doing the same for each CPU. This however
+ * is broken.
+ *
+ * Imagine for instance the case where two tasks block on one CPU, only the one
+ * CPU will have IO-wait accounted, while the other has regular idle. Even
+ * though, if the storage were faster, both could've ran at the same time,
+ * utilising both CPUs.
+ *
+ * This means, that when looking globally, the current IO-wait accounting on
+ * SMP is a lower bound, by reason of under accounting.
+ *
+ * Worse, since the numbers are provided per CPU, they are sometimes
+ * interpreted per CPU, and that is nonsensical. A blocked task isn't strictly
+ * associated with any one particular CPU, it can wake to another CPU than it
+ * blocked on. This means the per CPU IO-wait number is meaningless.
+ *
+ * Task CPU affinities can make all that even more 'interesting'.
+ */
+
+unsigned int nr_iowait(void)
+{
+	unsigned int i, sum = 0;
+
+	for_each_possible_cpu(i)
+		sum += nr_iowait_cpu(i);
+
+	return sum;
+}
+
+#ifdef CONFIG_SMP
+
+/*
+ * sched_exec - execve() is a valuable balancing opportunity, because at
+ * this point the task has the smallest effective memory and cache footprint.
+ */
+void sched_exec(void)
+{
+	struct task_struct *p = current;
+	unsigned long flags;
+	int dest_cpu;
+
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), WF_EXEC);
+	if (dest_cpu == smp_processor_id())
+		goto unlock;
+
+	if (likely(cpu_active(dest_cpu))) {
+		struct migration_arg arg = { p, dest_cpu };
+
+		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+		stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
+		return;
+	}
+unlock:
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+}
+
+#endif
+
+DEFINE_PER_CPU(struct kernel_stat, kstat);
+DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
+
+EXPORT_PER_CPU_SYMBOL(kstat);
+EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
+
+/*
+ * The function fair_sched_class.update_curr accesses the struct curr
+ * and its field curr->exec_start; when called from task_sched_runtime(),
+ * we observe a high rate of cache misses in practice.
+ * Prefetching this data results in improved performance.
+ */
+static inline void prefetch_curr_exec_start(struct task_struct *p)
+{
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	struct sched_entity *curr = (&p->se)->cfs_rq->curr;
+#else
+	struct sched_entity *curr = (&task_rq(p)->cfs)->curr;
+#endif
+	prefetch(curr);
+	prefetch(&curr->exec_start);
+}
+
+/*
+ * Return accounted runtime for the task.
+ * In case the task is currently running, return the runtime plus current's
+ * pending runtime that have not been accounted yet.
+ */
+unsigned long long task_sched_runtime(struct task_struct *p)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+	u64 ns;
+
+#if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
+	/*
+	 * 64-bit doesn't need locks to atomically read a 64-bit value.
+	 * So we have a optimization chance when the task's delta_exec is 0.
+	 * Reading ->on_cpu is racy, but this is ok.
+	 *
+	 * If we race with it leaving CPU, we'll take a lock. So we're correct.
+	 * If we race with it entering CPU, unaccounted time is 0. This is
+	 * indistinguishable from the read occurring a few cycles earlier.
+	 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
+	 * been accounted, so we're correct here as well.
+	 */
+	if (!p->on_cpu || !task_on_rq_queued(p))
+		return p->se.sum_exec_runtime;
+#endif
+
+	rq = task_rq_lock(p, &rf);
+	/*
+	 * Must be ->curr _and_ ->on_rq.  If dequeued, we would
+	 * project cycles that may never be accounted to this
+	 * thread, breaking clock_gettime().
+	 */
+	if (task_current(rq, p) && task_on_rq_queued(p)) {
+		prefetch_curr_exec_start(p);
+		update_rq_clock(rq);
+		p->sched_class->update_curr(rq);
+	}
+	ns = p->se.sum_exec_runtime;
+	task_rq_unlock(rq, p, &rf);
+
+	return ns;
+}
+
+#ifdef CONFIG_SCHED_DEBUG
+static u64 cpu_resched_latency(struct rq *rq)
+{
+	int latency_warn_ms = READ_ONCE(sysctl_resched_latency_warn_ms);
+	u64 resched_latency, now = rq_clock(rq);
+	static bool warned_once;
+
+	if (sysctl_resched_latency_warn_once && warned_once)
+		return 0;
+
+	if (!need_resched() || !latency_warn_ms)
+		return 0;
+
+	if (system_state == SYSTEM_BOOTING)
+		return 0;
+
+	if (!rq->last_seen_need_resched_ns) {
+		rq->last_seen_need_resched_ns = now;
+		rq->ticks_without_resched = 0;
+		return 0;
+	}
+
+	rq->ticks_without_resched++;
+	resched_latency = now - rq->last_seen_need_resched_ns;
+	if (resched_latency <= latency_warn_ms * NSEC_PER_MSEC)
+		return 0;
+
+	warned_once = true;
+
+	return resched_latency;
+}
+
+static int __init setup_resched_latency_warn_ms(char *str)
+{
+	long val;
+
+	if ((kstrtol(str, 0, &val))) {
+		pr_warn("Unable to set resched_latency_warn_ms\n");
+		return 1;
+	}
+
+	sysctl_resched_latency_warn_ms = val;
+	return 1;
+}
+__setup("resched_latency_warn_ms=", setup_resched_latency_warn_ms);
+#else
+static inline u64 cpu_resched_latency(struct rq *rq) { return 0; }
+#endif /* CONFIG_SCHED_DEBUG */
+
+/*
+ * This function gets called by the timer code, with HZ frequency.
+ * We call it with interrupts disabled.
+ */
+void scheduler_tick(void)
+{
+	int cpu = smp_processor_id();
+	struct rq *rq = cpu_rq(cpu);
+	struct task_struct *curr = rq->curr;
+	struct rq_flags rf;
+	unsigned long thermal_pressure;
+	u64 resched_latency;
+
+	if (housekeeping_cpu(cpu, HK_TYPE_TICK))
+		arch_scale_freq_tick();
+
+	sched_clock_tick();
+
+	rq_lock(rq, &rf);
+
+	update_rq_clock(rq);
+	thermal_pressure = arch_scale_thermal_pressure(cpu_of(rq));
+	update_thermal_load_avg(rq_clock_thermal(rq), rq, thermal_pressure);
+	curr->sched_class->task_tick(rq, curr, 0);
+	if (sched_feat(LATENCY_WARN))
+		resched_latency = cpu_resched_latency(rq);
+	calc_global_load_tick(rq);
+	sched_core_tick(rq);
+
+	rq_unlock(rq, &rf);
+
+	if (sched_feat(LATENCY_WARN) && resched_latency)
+		resched_latency_warn(cpu, resched_latency);
+
+	perf_event_task_tick();
+
+#ifdef CONFIG_SMP
+	rq->idle_balance = idle_cpu(cpu);
+	trigger_load_balance(rq);
+#endif
+}
+
+#ifdef CONFIG_NO_HZ_FULL
+
+struct tick_work {
+	int			cpu;
+	atomic_t		state;
+	struct delayed_work	work;
+};
+/* Values for ->state, see diagram below. */
+#define TICK_SCHED_REMOTE_OFFLINE	0
+#define TICK_SCHED_REMOTE_OFFLINING	1
+#define TICK_SCHED_REMOTE_RUNNING	2
+
+/*
+ * State diagram for ->state:
+ *
+ *
+ *          TICK_SCHED_REMOTE_OFFLINE
+ *                    |   ^
+ *                    |   |
+ *                    |   | sched_tick_remote()
+ *                    |   |
+ *                    |   |
+ *                    +--TICK_SCHED_REMOTE_OFFLINING
+ *                    |   ^
+ *                    |   |
+ * sched_tick_start() |   | sched_tick_stop()
+ *                    |   |
+ *                    V   |
+ *          TICK_SCHED_REMOTE_RUNNING
+ *
+ *
+ * Other transitions get WARN_ON_ONCE(), except that sched_tick_remote()
+ * and sched_tick_start() are happy to leave the state in RUNNING.
+ */
+
+static struct tick_work __percpu *tick_work_cpu;
+
+static void sched_tick_remote(struct work_struct *work)
+{
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct tick_work *twork = container_of(dwork, struct tick_work, work);
+	int cpu = twork->cpu;
+	struct rq *rq = cpu_rq(cpu);
+	struct task_struct *curr;
+	struct rq_flags rf;
+	u64 delta;
+	int os;
+
+	/*
+	 * Handle the tick only if it appears the remote CPU is running in full
+	 * dynticks mode. The check is racy by nature, but missing a tick or
+	 * having one too much is no big deal because the scheduler tick updates
+	 * statistics and checks timeslices in a time-independent way, regardless
+	 * of when exactly it is running.
+	 */
+	if (!tick_nohz_tick_stopped_cpu(cpu))
+		goto out_requeue;
+
+	rq_lock_irq(rq, &rf);
+	curr = rq->curr;
+	if (cpu_is_offline(cpu))
+		goto out_unlock;
+
+	update_rq_clock(rq);
+
+	if (!is_idle_task(curr)) {
+		/*
+		 * Make sure the next tick runs within a reasonable
+		 * amount of time.
+		 */
+		delta = rq_clock_task(rq) - curr->se.exec_start;
+		WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3);
+	}
+	curr->sched_class->task_tick(rq, curr, 0);
+
+	calc_load_nohz_remote(rq);
+out_unlock:
+	rq_unlock_irq(rq, &rf);
+out_requeue:
+
+	/*
+	 * Run the remote tick once per second (1Hz). This arbitrary
+	 * frequency is large enough to avoid overload but short enough
+	 * to keep scheduler internal stats reasonably up to date.  But
+	 * first update state to reflect hotplug activity if required.
+	 */
+	os = atomic_fetch_add_unless(&twork->state, -1, TICK_SCHED_REMOTE_RUNNING);
+	WARN_ON_ONCE(os == TICK_SCHED_REMOTE_OFFLINE);
+	if (os == TICK_SCHED_REMOTE_RUNNING)
+		queue_delayed_work(system_unbound_wq, dwork, HZ);
+}
+
+static void sched_tick_start(int cpu)
+{
+	int os;
+	struct tick_work *twork;
+
+	if (housekeeping_cpu(cpu, HK_TYPE_TICK))
+		return;
+
+	WARN_ON_ONCE(!tick_work_cpu);
+
+	twork = per_cpu_ptr(tick_work_cpu, cpu);
+	os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_RUNNING);
+	WARN_ON_ONCE(os == TICK_SCHED_REMOTE_RUNNING);
+	if (os == TICK_SCHED_REMOTE_OFFLINE) {
+		twork->cpu = cpu;
+		INIT_DELAYED_WORK(&twork->work, sched_tick_remote);
+		queue_delayed_work(system_unbound_wq, &twork->work, HZ);
+	}
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void sched_tick_stop(int cpu)
+{
+	struct tick_work *twork;
+	int os;
+
+	if (housekeeping_cpu(cpu, HK_TYPE_TICK))
+		return;
+
+	WARN_ON_ONCE(!tick_work_cpu);
+
+	twork = per_cpu_ptr(tick_work_cpu, cpu);
+	/* There cannot be competing actions, but don't rely on stop-machine. */
+	os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_OFFLINING);
+	WARN_ON_ONCE(os != TICK_SCHED_REMOTE_RUNNING);
+	/* Don't cancel, as this would mess up the state machine. */
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
+int __init sched_tick_offload_init(void)
+{
+	tick_work_cpu = alloc_percpu(struct tick_work);
+	BUG_ON(!tick_work_cpu);
+	return 0;
+}
+
+#else /* !CONFIG_NO_HZ_FULL */
+static inline void sched_tick_start(int cpu) { }
+static inline void sched_tick_stop(int cpu) { }
+#endif
+
+#if defined(CONFIG_PREEMPTION) && (defined(CONFIG_DEBUG_PREEMPT) || \
+				defined(CONFIG_TRACE_PREEMPT_TOGGLE))
+/*
+ * If the value passed in is equal to the current preempt count
+ * then we just disabled preemption. Start timing the latency.
+ */
+static inline void preempt_latency_start(int val)
+{
+	if (preempt_count() == val) {
+		unsigned long ip = get_lock_parent_ip();
+#ifdef CONFIG_DEBUG_PREEMPT
+		current->preempt_disable_ip = ip;
+#endif
+		trace_preempt_off(CALLER_ADDR0, ip);
+	}
+}
+
+void preempt_count_add(int val)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+	/*
+	 * Underflow?
+	 */
+	if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
+		return;
+#endif
+	__preempt_count_add(val);
+#ifdef CONFIG_DEBUG_PREEMPT
+	/*
+	 * Spinlock count overflowing soon?
+	 */
+	DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
+				PREEMPT_MASK - 10);
+#endif
+	preempt_latency_start(val);
+}
+EXPORT_SYMBOL(preempt_count_add);
+NOKPROBE_SYMBOL(preempt_count_add);
+
+/*
+ * If the value passed in equals to the current preempt count
+ * then we just enabled preemption. Stop timing the latency.
+ */
+static inline void preempt_latency_stop(int val)
+{
+	if (preempt_count() == val)
+		trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
+}
+
+void preempt_count_sub(int val)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+	/*
+	 * Underflow?
+	 */
+	if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
+		return;
+	/*
+	 * Is the spinlock portion underflowing?
+	 */
+	if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
+			!(preempt_count() & PREEMPT_MASK)))
+		return;
+#endif
+
+	preempt_latency_stop(val);
+	__preempt_count_sub(val);
+}
+EXPORT_SYMBOL(preempt_count_sub);
+NOKPROBE_SYMBOL(preempt_count_sub);
+
+#else
+static inline void preempt_latency_start(int val) { }
+static inline void preempt_latency_stop(int val) { }
+#endif
+
+static inline unsigned long get_preempt_disable_ip(struct task_struct *p)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+	return p->preempt_disable_ip;
+#else
+	return 0;
+#endif
+}
+
+/*
+ * Print scheduling while atomic bug:
+ */
+static noinline void __schedule_bug(struct task_struct *prev)
+{
+	/* Save this before calling printk(), since that will clobber it */
+	unsigned long preempt_disable_ip = get_preempt_disable_ip(current);
+
+	if (oops_in_progress)
+		return;
+
+	printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
+		prev->comm, prev->pid, preempt_count());
+
+	debug_show_held_locks(prev);
+	print_modules();
+	if (irqs_disabled())
+		print_irqtrace_events(prev);
+	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
+	    && in_atomic_preempt_off()) {
+		pr_err("Preemption disabled at:");
+		print_ip_sym(KERN_ERR, preempt_disable_ip);
+	}
+	check_panic_on_warn("scheduling while atomic");
+
+	dump_stack();
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+
+/*
+ * Various schedule()-time debugging checks and statistics:
+ */
+static inline void schedule_debug(struct task_struct *prev, bool preempt)
+{
+#ifdef CONFIG_SCHED_STACK_END_CHECK
+	if (task_stack_end_corrupted(prev))
+		panic("corrupted stack end detected inside scheduler\n");
+
+	if (task_scs_end_corrupted(prev))
+		panic("corrupted shadow stack detected inside scheduler\n");
+#endif
+
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+	if (!preempt && READ_ONCE(prev->__state) && prev->non_block_count) {
+		printk(KERN_ERR "BUG: scheduling in a non-blocking section: %s/%d/%i\n",
+			prev->comm, prev->pid, prev->non_block_count);
+		dump_stack();
+		add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+	}
+#endif
+
+	if (unlikely(in_atomic_preempt_off())) {
+		__schedule_bug(prev);
+		preempt_count_set(PREEMPT_DISABLED);
+	}
+	rcu_sleep_check();
+	SCHED_WARN_ON(ct_state() == CONTEXT_USER);
+
+	profile_hit(SCHED_PROFILING, __builtin_return_address(0));
+
+	schedstat_inc(this_rq()->sched_count);
+}
+
+static void put_prev_task_balance(struct rq *rq, struct task_struct *prev,
+				  struct rq_flags *rf)
+{
+#ifdef CONFIG_SMP
+	const struct sched_class *class;
+	/*
+	 * We must do the balancing pass before put_prev_task(), such
+	 * that when we release the rq->lock the task is in the same
+	 * state as before we took rq->lock.
+	 *
+	 * We can terminate the balance pass as soon as we know there is
+	 * a runnable task of @class priority or higher.
+	 */
+	for_class_range(class, prev->sched_class, &idle_sched_class) {
+		if (class->balance(rq, prev, rf))
+			break;
+	}
+#endif
+
+	put_prev_task(rq, prev);
+}
+
+/*
+ * Pick up the highest-prio task:
+ */
+static inline struct task_struct *
+__pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	const struct sched_class *class;
+	struct task_struct *p;
+
+	/*
+	 * Optimization: we know that if all tasks are in the fair class we can
+	 * call that function directly, but only if the @prev task wasn't of a
+	 * higher scheduling class, because otherwise those lose the
+	 * opportunity to pull in more work from other CPUs.
+	 */
+	if (likely(!sched_class_above(prev->sched_class, &fair_sched_class) &&
+		   rq->nr_running == rq->cfs.h_nr_running)) {
+
+		p = pick_next_task_fair(rq, prev, rf);
+		if (unlikely(p == RETRY_TASK))
+			goto restart;
+
+		/* Assume the next prioritized class is idle_sched_class */
+		if (!p) {
+			put_prev_task(rq, prev);
+			p = pick_next_task_idle(rq);
+		}
+
+		return p;
+	}
+
+restart:
+	put_prev_task_balance(rq, prev, rf);
+
+	for_each_class(class) {
+		p = class->pick_next_task(rq);
+		if (p)
+			return p;
+	}
+
+	BUG(); /* The idle class should always have a runnable task. */
+}
+
+#ifdef CONFIG_SCHED_CORE
+static inline bool is_task_rq_idle(struct task_struct *t)
+{
+	return (task_rq(t)->idle == t);
+}
+
+static inline bool cookie_equals(struct task_struct *a, unsigned long cookie)
+{
+	return is_task_rq_idle(a) || (a->core_cookie == cookie);
+}
+
+static inline bool cookie_match(struct task_struct *a, struct task_struct *b)
+{
+	if (is_task_rq_idle(a) || is_task_rq_idle(b))
+		return true;
+
+	return a->core_cookie == b->core_cookie;
+}
+
+static inline struct task_struct *pick_task(struct rq *rq)
+{
+	const struct sched_class *class;
+	struct task_struct *p;
+
+	for_each_class(class) {
+		p = class->pick_task(rq);
+		if (p)
+			return p;
+	}
+
+	BUG(); /* The idle class should always have a runnable task. */
+}
+
+extern void task_vruntime_update(struct rq *rq, struct task_struct *p, bool in_fi);
+
+static void queue_core_balance(struct rq *rq);
+
+static struct task_struct *
+pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	struct task_struct *next, *p, *max = NULL;
+	const struct cpumask *smt_mask;
+	bool fi_before = false;
+	bool core_clock_updated = (rq == rq->core);
+	unsigned long cookie;
+	int i, cpu, occ = 0;
+	struct rq *rq_i;
+	bool need_sync;
+
+	if (!sched_core_enabled(rq))
+		return __pick_next_task(rq, prev, rf);
+
+	cpu = cpu_of(rq);
+
+	/* Stopper task is switching into idle, no need core-wide selection. */
+	if (cpu_is_offline(cpu)) {
+		/*
+		 * Reset core_pick so that we don't enter the fastpath when
+		 * coming online. core_pick would already be migrated to
+		 * another cpu during offline.
+		 */
+		rq->core_pick = NULL;
+		return __pick_next_task(rq, prev, rf);
+	}
+
+	/*
+	 * If there were no {en,de}queues since we picked (IOW, the task
+	 * pointers are all still valid), and we haven't scheduled the last
+	 * pick yet, do so now.
+	 *
+	 * rq->core_pick can be NULL if no selection was made for a CPU because
+	 * it was either offline or went offline during a sibling's core-wide
+	 * selection. In this case, do a core-wide selection.
+	 */
+	if (rq->core->core_pick_seq == rq->core->core_task_seq &&
+	    rq->core->core_pick_seq != rq->core_sched_seq &&
+	    rq->core_pick) {
+		WRITE_ONCE(rq->core_sched_seq, rq->core->core_pick_seq);
+
+		next = rq->core_pick;
+		if (next != prev) {
+			put_prev_task(rq, prev);
+			set_next_task(rq, next);
+		}
+
+		rq->core_pick = NULL;
+		goto out;
+	}
+
+	put_prev_task_balance(rq, prev, rf);
+
+	smt_mask = cpu_smt_mask(cpu);
+	need_sync = !!rq->core->core_cookie;
+
+	/* reset state */
+	rq->core->core_cookie = 0UL;
+	if (rq->core->core_forceidle_count) {
+		if (!core_clock_updated) {
+			update_rq_clock(rq->core);
+			core_clock_updated = true;
+		}
+		sched_core_account_forceidle(rq);
+		/* reset after accounting force idle */
+		rq->core->core_forceidle_start = 0;
+		rq->core->core_forceidle_count = 0;
+		rq->core->core_forceidle_occupation = 0;
+		need_sync = true;
+		fi_before = true;
+	}
+
+	/*
+	 * core->core_task_seq, core->core_pick_seq, rq->core_sched_seq
+	 *
+	 * @task_seq guards the task state ({en,de}queues)
+	 * @pick_seq is the @task_seq we did a selection on
+	 * @sched_seq is the @pick_seq we scheduled
+	 *
+	 * However, preemptions can cause multiple picks on the same task set.
+	 * 'Fix' this by also increasing @task_seq for every pick.
+	 */
+	rq->core->core_task_seq++;
+
+	/*
+	 * Optimize for common case where this CPU has no cookies
+	 * and there are no cookied tasks running on siblings.
+	 */
+	if (!need_sync) {
+		next = pick_task(rq);
+		if (!next->core_cookie) {
+			rq->core_pick = NULL;
+			/*
+			 * For robustness, update the min_vruntime_fi for
+			 * unconstrained picks as well.
+			 */
+			WARN_ON_ONCE(fi_before);
+			task_vruntime_update(rq, next, false);
+			goto out_set_next;
+		}
+	}
+
+	/*
+	 * For each thread: do the regular task pick and find the max prio task
+	 * amongst them.
+	 *
+	 * Tie-break prio towards the current CPU
+	 */
+	for_each_cpu_wrap(i, smt_mask, cpu) {
+		rq_i = cpu_rq(i);
+
+		/*
+		 * Current cpu always has its clock updated on entrance to
+		 * pick_next_task(). If the current cpu is not the core,
+		 * the core may also have been updated above.
+		 */
+		if (i != cpu && (rq_i != rq->core || !core_clock_updated))
+			update_rq_clock(rq_i);
+
+		p = rq_i->core_pick = pick_task(rq_i);
+		if (!max || prio_less(max, p, fi_before))
+			max = p;
+	}
+
+	cookie = rq->core->core_cookie = max->core_cookie;
+
+	/*
+	 * For each thread: try and find a runnable task that matches @max or
+	 * force idle.
+	 */
+	for_each_cpu(i, smt_mask) {
+		rq_i = cpu_rq(i);
+		p = rq_i->core_pick;
+
+		if (!cookie_equals(p, cookie)) {
+			p = NULL;
+			if (cookie)
+				p = sched_core_find(rq_i, cookie);
+			if (!p)
+				p = idle_sched_class.pick_task(rq_i);
+		}
+
+		rq_i->core_pick = p;
+
+		if (p == rq_i->idle) {
+			if (rq_i->nr_running) {
+				rq->core->core_forceidle_count++;
+				if (!fi_before)
+					rq->core->core_forceidle_seq++;
+			}
+		} else {
+			occ++;
+		}
+	}
+
+	if (schedstat_enabled() && rq->core->core_forceidle_count) {
+		rq->core->core_forceidle_start = rq_clock(rq->core);
+		rq->core->core_forceidle_occupation = occ;
+	}
+
+	rq->core->core_pick_seq = rq->core->core_task_seq;
+	next = rq->core_pick;
+	rq->core_sched_seq = rq->core->core_pick_seq;
+
+	/* Something should have been selected for current CPU */
+	WARN_ON_ONCE(!next);
+
+	/*
+	 * Reschedule siblings
+	 *
+	 * NOTE: L1TF -- at this point we're no longer running the old task and
+	 * sending an IPI (below) ensures the sibling will no longer be running
+	 * their task. This ensures there is no inter-sibling overlap between
+	 * non-matching user state.
+	 */
+	for_each_cpu(i, smt_mask) {
+		rq_i = cpu_rq(i);
+
+		/*
+		 * An online sibling might have gone offline before a task
+		 * could be picked for it, or it might be offline but later
+		 * happen to come online, but its too late and nothing was
+		 * picked for it.  That's Ok - it will pick tasks for itself,
+		 * so ignore it.
+		 */
+		if (!rq_i->core_pick)
+			continue;
+
+		/*
+		 * Update for new !FI->FI transitions, or if continuing to be in !FI:
+		 * fi_before     fi      update?
+		 *  0            0       1
+		 *  0            1       1
+		 *  1            0       1
+		 *  1            1       0
+		 */
+		if (!(fi_before && rq->core->core_forceidle_count))
+			task_vruntime_update(rq_i, rq_i->core_pick, !!rq->core->core_forceidle_count);
+
+		rq_i->core_pick->core_occupation = occ;
+
+		if (i == cpu) {
+			rq_i->core_pick = NULL;
+			continue;
+		}
+
+		/* Did we break L1TF mitigation requirements? */
+		WARN_ON_ONCE(!cookie_match(next, rq_i->core_pick));
+
+		if (rq_i->curr == rq_i->core_pick) {
+			rq_i->core_pick = NULL;
+			continue;
+		}
+
+		resched_curr(rq_i);
+	}
+
+out_set_next:
+	set_next_task(rq, next);
+out:
+	if (rq->core->core_forceidle_count && next == rq->idle)
+		queue_core_balance(rq);
+
+	return next;
+}
+
+static bool try_steal_cookie(int this, int that)
+{
+	struct rq *dst = cpu_rq(this), *src = cpu_rq(that);
+	struct task_struct *p;
+	unsigned long cookie;
+	bool success = false;
+
+	local_irq_disable();
+	double_rq_lock(dst, src);
+
+	cookie = dst->core->core_cookie;
+	if (!cookie)
+		goto unlock;
+
+	if (dst->curr != dst->idle)
+		goto unlock;
+
+	p = sched_core_find(src, cookie);
+	if (p == src->idle)
+		goto unlock;
+
+	do {
+		if (p == src->core_pick || p == src->curr)
+			goto next;
+
+		if (!is_cpu_allowed(p, this))
+			goto next;
+
+		if (p->core_occupation > dst->idle->core_occupation)
+			goto next;
+
+		deactivate_task(src, p, 0);
+		set_task_cpu(p, this);
+		activate_task(dst, p, 0);
+
+		resched_curr(dst);
+
+		success = true;
+		break;
+
+next:
+		p = sched_core_next(p, cookie);
+	} while (p);
+
+unlock:
+	double_rq_unlock(dst, src);
+	local_irq_enable();
+
+	return success;
+}
+
+static bool steal_cookie_task(int cpu, struct sched_domain *sd)
+{
+	int i;
+
+	for_each_cpu_wrap(i, sched_domain_span(sd), cpu) {
+		if (i == cpu)
+			continue;
+
+		if (need_resched())
+			break;
+
+		if (try_steal_cookie(cpu, i))
+			return true;
+	}
+
+	return false;
+}
+
+static void sched_core_balance(struct rq *rq)
+{
+	struct sched_domain *sd;
+	int cpu = cpu_of(rq);
+
+	preempt_disable();
+	rcu_read_lock();
+	raw_spin_rq_unlock_irq(rq);
+	for_each_domain(cpu, sd) {
+		if (need_resched())
+			break;
+
+		if (steal_cookie_task(cpu, sd))
+			break;
+	}
+	raw_spin_rq_lock_irq(rq);
+	rcu_read_unlock();
+	preempt_enable();
+}
+
+static DEFINE_PER_CPU(struct balance_callback, core_balance_head);
+
+static void queue_core_balance(struct rq *rq)
+{
+	if (!sched_core_enabled(rq))
+		return;
+
+	if (!rq->core->core_cookie)
+		return;
+
+	if (!rq->nr_running) /* not forced idle */
+		return;
+
+	queue_balance_callback(rq, &per_cpu(core_balance_head, rq->cpu), sched_core_balance);
+}
+
+static void sched_core_cpu_starting(unsigned int cpu)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+	struct rq *rq = cpu_rq(cpu), *core_rq = NULL;
+	unsigned long flags;
+	int t;
+
+	sched_core_lock(cpu, &flags);
+
+	WARN_ON_ONCE(rq->core != rq);
+
+	/* if we're the first, we'll be our own leader */
+	if (cpumask_weight(smt_mask) == 1)
+		goto unlock;
+
+	/* find the leader */
+	for_each_cpu(t, smt_mask) {
+		if (t == cpu)
+			continue;
+		rq = cpu_rq(t);
+		if (rq->core == rq) {
+			core_rq = rq;
+			break;
+		}
+	}
+
+	if (WARN_ON_ONCE(!core_rq)) /* whoopsie */
+		goto unlock;
+
+	/* install and validate core_rq */
+	for_each_cpu(t, smt_mask) {
+		rq = cpu_rq(t);
+
+		if (t == cpu)
+			rq->core = core_rq;
+
+		WARN_ON_ONCE(rq->core != core_rq);
+	}
+
+unlock:
+	sched_core_unlock(cpu, &flags);
+}
+
+static void sched_core_cpu_deactivate(unsigned int cpu)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+	struct rq *rq = cpu_rq(cpu), *core_rq = NULL;
+	unsigned long flags;
+	int t;
+
+	sched_core_lock(cpu, &flags);
+
+	/* if we're the last man standing, nothing to do */
+	if (cpumask_weight(smt_mask) == 1) {
+		WARN_ON_ONCE(rq->core != rq);
+		goto unlock;
+	}
+
+	/* if we're not the leader, nothing to do */
+	if (rq->core != rq)
+		goto unlock;
+
+	/* find a new leader */
+	for_each_cpu(t, smt_mask) {
+		if (t == cpu)
+			continue;
+		core_rq = cpu_rq(t);
+		break;
+	}
+
+	if (WARN_ON_ONCE(!core_rq)) /* impossible */
+		goto unlock;
+
+	/* copy the shared state to the new leader */
+	core_rq->core_task_seq             = rq->core_task_seq;
+	core_rq->core_pick_seq             = rq->core_pick_seq;
+	core_rq->core_cookie               = rq->core_cookie;
+	core_rq->core_forceidle_count      = rq->core_forceidle_count;
+	core_rq->core_forceidle_seq        = rq->core_forceidle_seq;
+	core_rq->core_forceidle_occupation = rq->core_forceidle_occupation;
+
+	/*
+	 * Accounting edge for forced idle is handled in pick_next_task().
+	 * Don't need another one here, since the hotplug thread shouldn't
+	 * have a cookie.
+	 */
+	core_rq->core_forceidle_start = 0;
+
+	/* install new leader */
+	for_each_cpu(t, smt_mask) {
+		rq = cpu_rq(t);
+		rq->core = core_rq;
+	}
+
+unlock:
+	sched_core_unlock(cpu, &flags);
+}
+
+static inline void sched_core_cpu_dying(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (rq->core != rq)
+		rq->core = rq;
+}
+
+#else /* !CONFIG_SCHED_CORE */
+
+static inline void sched_core_cpu_starting(unsigned int cpu) {}
+static inline void sched_core_cpu_deactivate(unsigned int cpu) {}
+static inline void sched_core_cpu_dying(unsigned int cpu) {}
+
+static struct task_struct *
+pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	return __pick_next_task(rq, prev, rf);
+}
+
+#endif /* CONFIG_SCHED_CORE */
+
+/*
+ * Constants for the sched_mode argument of __schedule().
+ *
+ * The mode argument allows RT enabled kernels to differentiate a
+ * preemption from blocking on an 'sleeping' spin/rwlock. Note that
+ * SM_MASK_PREEMPT for !RT has all bits set, which allows the compiler to
+ * optimize the AND operation out and just check for zero.
+ */
+#define SM_NONE			0x0
+#define SM_PREEMPT		0x1
+#define SM_RTLOCK_WAIT		0x2
+
+#ifndef CONFIG_PREEMPT_RT
+# define SM_MASK_PREEMPT	(~0U)
+#else
+# define SM_MASK_PREEMPT	SM_PREEMPT
+#endif
+
+/*
+ * __schedule() is the main scheduler function.
+ *
+ * The main means of driving the scheduler and thus entering this function are:
+ *
+ *   1. Explicit blocking: mutex, semaphore, waitqueue, etc.
+ *
+ *   2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
+ *      paths. For example, see arch/x86/entry_64.S.
+ *
+ *      To drive preemption between tasks, the scheduler sets the flag in timer
+ *      interrupt handler scheduler_tick().
+ *
+ *   3. Wakeups don't really cause entry into schedule(). They add a
+ *      task to the run-queue and that's it.
+ *
+ *      Now, if the new task added to the run-queue preempts the current
+ *      task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
+ *      called on the nearest possible occasion:
+ *
+ *       - If the kernel is preemptible (CONFIG_PREEMPTION=y):
+ *
+ *         - in syscall or exception context, at the next outmost
+ *           preempt_enable(). (this might be as soon as the wake_up()'s
+ *           spin_unlock()!)
+ *
+ *         - in IRQ context, return from interrupt-handler to
+ *           preemptible context
+ *
+ *       - If the kernel is not preemptible (CONFIG_PREEMPTION is not set)
+ *         then at the next:
+ *
+ *          - cond_resched() call
+ *          - explicit schedule() call
+ *          - return from syscall or exception to user-space
+ *          - return from interrupt-handler to user-space
+ *
+ * WARNING: must be called with preemption disabled!
+ */
+static void __sched notrace __schedule(unsigned int sched_mode)
+{
+	struct task_struct *prev, *next;
+	unsigned long *switch_count;
+	unsigned long prev_state;
+	struct rq_flags rf;
+	struct rq *rq;
+	int cpu;
+
+	cpu = smp_processor_id();
+	rq = cpu_rq(cpu);
+	prev = rq->curr;
+
+	schedule_debug(prev, !!sched_mode);
+
+	if (sched_feat(HRTICK) || sched_feat(HRTICK_DL))
+		hrtick_clear(rq);
+
+	local_irq_disable();
+	rcu_note_context_switch(!!sched_mode);
+
+	/*
+	 * Make sure that signal_pending_state()->signal_pending() below
+	 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
+	 * done by the caller to avoid the race with signal_wake_up():
+	 *
+	 * __set_current_state(@state)		signal_wake_up()
+	 * schedule()				  set_tsk_thread_flag(p, TIF_SIGPENDING)
+	 *					  wake_up_state(p, state)
+	 *   LOCK rq->lock			    LOCK p->pi_state
+	 *   smp_mb__after_spinlock()		    smp_mb__after_spinlock()
+	 *     if (signal_pending_state())	    if (p->state & @state)
+	 *
+	 * Also, the membarrier system call requires a full memory barrier
+	 * after coming from user-space, before storing to rq->curr.
+	 */
+	rq_lock(rq, &rf);
+	smp_mb__after_spinlock();
+
+	/* Promote REQ to ACT */
+	rq->clock_update_flags <<= 1;
+	update_rq_clock(rq);
+
+	switch_count = &prev->nivcsw;
+
+	/*
+	 * We must load prev->state once (task_struct::state is volatile), such
+	 * that we form a control dependency vs deactivate_task() below.
+	 */
+	prev_state = READ_ONCE(prev->__state);
+	if (!(sched_mode & SM_MASK_PREEMPT) && prev_state) {
+		if (signal_pending_state(prev_state, prev)) {
+			WRITE_ONCE(prev->__state, TASK_RUNNING);
+		} else {
+			prev->sched_contributes_to_load =
+				(prev_state & TASK_UNINTERRUPTIBLE) &&
+				!(prev_state & TASK_NOLOAD) &&
+				!(prev_state & TASK_FROZEN);
+
+			if (prev->sched_contributes_to_load)
+				rq->nr_uninterruptible++;
+
+			/*
+			 * __schedule()			ttwu()
+			 *   prev_state = prev->state;    if (p->on_rq && ...)
+			 *   if (prev_state)		    goto out;
+			 *     p->on_rq = 0;		  smp_acquire__after_ctrl_dep();
+			 *				  p->state = TASK_WAKING
+			 *
+			 * Where __schedule() and ttwu() have matching control dependencies.
+			 *
+			 * After this, schedule() must not care about p->state any more.
+			 */
+			deactivate_task(rq, prev, DEQUEUE_SLEEP | DEQUEUE_NOCLOCK);
+
+			if (prev->in_iowait) {
+				atomic_inc(&rq->nr_iowait);
+				delayacct_blkio_start();
+			}
+		}
+		switch_count = &prev->nvcsw;
+	}
+
+	next = pick_next_task(rq, prev, &rf);
+	clear_tsk_need_resched(prev);
+	clear_preempt_need_resched();
+#ifdef CONFIG_SCHED_DEBUG
+	rq->last_seen_need_resched_ns = 0;
+#endif
+
+	if (likely(prev != next)) {
+		rq->nr_switches++;
+		/*
+		 * RCU users of rcu_dereference(rq->curr) may not see
+		 * changes to task_struct made by pick_next_task().
+		 */
+		RCU_INIT_POINTER(rq->curr, next);
+		/*
+		 * The membarrier system call requires each architecture
+		 * to have a full memory barrier after updating
+		 * rq->curr, before returning to user-space.
+		 *
+		 * Here are the schemes providing that barrier on the
+		 * various architectures:
+		 * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC.
+		 *   switch_mm() rely on membarrier_arch_switch_mm() on PowerPC.
+		 * - finish_lock_switch() for weakly-ordered
+		 *   architectures where spin_unlock is a full barrier,
+		 * - switch_to() for arm64 (weakly-ordered, spin_unlock
+		 *   is a RELEASE barrier),
+		 */
+		++*switch_count;
+
+		migrate_disable_switch(rq, prev);
+		psi_sched_switch(prev, next, !task_on_rq_queued(prev));
+
+		trace_sched_switch(sched_mode & SM_MASK_PREEMPT, prev, next, prev_state);
+
+		/* Also unlocks the rq: */
+		rq = context_switch(rq, prev, next, &rf);
+	} else {
+		rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP);
+
+		rq_unpin_lock(rq, &rf);
+		__balance_callbacks(rq);
+		raw_spin_rq_unlock_irq(rq);
+	}
+}
+
+void __noreturn do_task_dead(void)
+{
+	/* Causes final put_task_struct in finish_task_switch(): */
+	set_special_state(TASK_DEAD);
+
+	/* Tell freezer to ignore us: */
+	current->flags |= PF_NOFREEZE;
+
+	__schedule(SM_NONE);
+	BUG();
+
+	/* Avoid "noreturn function does return" - but don't continue if BUG() is a NOP: */
+	for (;;)
+		cpu_relax();
+}
+
+static inline void sched_submit_work(struct task_struct *tsk)
+{
+	unsigned int task_flags;
+
+	if (task_is_running(tsk))
+		return;
+
+	task_flags = tsk->flags;
+	/*
+	 * If a worker goes to sleep, notify and ask workqueue whether it
+	 * wants to wake up a task to maintain concurrency.
+	 */
+	if (task_flags & (PF_WQ_WORKER | PF_IO_WORKER)) {
+		if (task_flags & PF_WQ_WORKER)
+			wq_worker_sleeping(tsk);
+		else
+			io_wq_worker_sleeping(tsk);
+	}
+
+	/*
+	 * spinlock and rwlock must not flush block requests.  This will
+	 * deadlock if the callback attempts to acquire a lock which is
+	 * already acquired.
+	 */
+	SCHED_WARN_ON(current->__state & TASK_RTLOCK_WAIT);
+
+	/*
+	 * If we are going to sleep and we have plugged IO queued,
+	 * make sure to submit it to avoid deadlocks.
+	 */
+	blk_flush_plug(tsk->plug, true);
+}
+
+static void sched_update_worker(struct task_struct *tsk)
+{
+	if (tsk->flags & (PF_WQ_WORKER | PF_IO_WORKER)) {
+		if (tsk->flags & PF_WQ_WORKER)
+			wq_worker_running(tsk);
+		else
+			io_wq_worker_running(tsk);
+	}
+}
+
+asmlinkage __visible void __sched schedule(void)
+{
+	struct task_struct *tsk = current;
+
+	sched_submit_work(tsk);
+	do {
+		preempt_disable();
+		__schedule(SM_NONE);
+		sched_preempt_enable_no_resched();
+	} while (need_resched());
+	sched_update_worker(tsk);
+}
+EXPORT_SYMBOL(schedule);
+
+/*
+ * synchronize_rcu_tasks() makes sure that no task is stuck in preempted
+ * state (have scheduled out non-voluntarily) by making sure that all
+ * tasks have either left the run queue or have gone into user space.
+ * As idle tasks do not do either, they must not ever be preempted
+ * (schedule out non-voluntarily).
+ *
+ * schedule_idle() is similar to schedule_preempt_disable() except that it
+ * never enables preemption because it does not call sched_submit_work().
+ */
+void __sched schedule_idle(void)
+{
+	/*
+	 * As this skips calling sched_submit_work(), which the idle task does
+	 * regardless because that function is a nop when the task is in a
+	 * TASK_RUNNING state, make sure this isn't used someplace that the
+	 * current task can be in any other state. Note, idle is always in the
+	 * TASK_RUNNING state.
+	 */
+	WARN_ON_ONCE(current->__state);
+	do {
+		__schedule(SM_NONE);
+	} while (need_resched());
+}
+
+#if defined(CONFIG_CONTEXT_TRACKING_USER) && !defined(CONFIG_HAVE_CONTEXT_TRACKING_USER_OFFSTACK)
+asmlinkage __visible void __sched schedule_user(void)
+{
+	/*
+	 * If we come here after a random call to set_need_resched(),
+	 * or we have been woken up remotely but the IPI has not yet arrived,
+	 * we haven't yet exited the RCU idle mode. Do it here manually until
+	 * we find a better solution.
+	 *
+	 * NB: There are buggy callers of this function.  Ideally we
+	 * should warn if prev_state != CONTEXT_USER, but that will trigger
+	 * too frequently to make sense yet.
+	 */
+	enum ctx_state prev_state = exception_enter();
+	schedule();
+	exception_exit(prev_state);
+}
+#endif
+
+/**
+ * schedule_preempt_disabled - called with preemption disabled
+ *
+ * Returns with preemption disabled. Note: preempt_count must be 1
+ */
+void __sched schedule_preempt_disabled(void)
+{
+	sched_preempt_enable_no_resched();
+	schedule();
+	preempt_disable();
+}
+
+#ifdef CONFIG_PREEMPT_RT
+void __sched notrace schedule_rtlock(void)
+{
+	do {
+		preempt_disable();
+		__schedule(SM_RTLOCK_WAIT);
+		sched_preempt_enable_no_resched();
+	} while (need_resched());
+}
+NOKPROBE_SYMBOL(schedule_rtlock);
+#endif
+
+static void __sched notrace preempt_schedule_common(void)
+{
+	do {
+		/*
+		 * Because the function tracer can trace preempt_count_sub()
+		 * and it also uses preempt_enable/disable_notrace(), if
+		 * NEED_RESCHED is set, the preempt_enable_notrace() called
+		 * by the function tracer will call this function again and
+		 * cause infinite recursion.
+		 *
+		 * Preemption must be disabled here before the function
+		 * tracer can trace. Break up preempt_disable() into two
+		 * calls. One to disable preemption without fear of being
+		 * traced. The other to still record the preemption latency,
+		 * which can also be traced by the function tracer.
+		 */
+		preempt_disable_notrace();
+		preempt_latency_start(1);
+		__schedule(SM_PREEMPT);
+		preempt_latency_stop(1);
+		preempt_enable_no_resched_notrace();
+
+		/*
+		 * Check again in case we missed a preemption opportunity
+		 * between schedule and now.
+		 */
+	} while (need_resched());
+}
+
+#ifdef CONFIG_PREEMPTION
+/*
+ * This is the entry point to schedule() from in-kernel preemption
+ * off of preempt_enable.
+ */
+asmlinkage __visible void __sched notrace preempt_schedule(void)
+{
+	/*
+	 * If there is a non-zero preempt_count or interrupts are disabled,
+	 * we do not want to preempt the current task. Just return..
+	 */
+	if (likely(!preemptible()))
+		return;
+	preempt_schedule_common();
+}
+NOKPROBE_SYMBOL(preempt_schedule);
+EXPORT_SYMBOL(preempt_schedule);
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
+#ifndef preempt_schedule_dynamic_enabled
+#define preempt_schedule_dynamic_enabled	preempt_schedule
+#define preempt_schedule_dynamic_disabled	NULL
+#endif
+DEFINE_STATIC_CALL(preempt_schedule, preempt_schedule_dynamic_enabled);
+EXPORT_STATIC_CALL_TRAMP(preempt_schedule);
+#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
+static DEFINE_STATIC_KEY_TRUE(sk_dynamic_preempt_schedule);
+void __sched notrace dynamic_preempt_schedule(void)
+{
+	if (!static_branch_unlikely(&sk_dynamic_preempt_schedule))
+		return;
+	preempt_schedule();
+}
+NOKPROBE_SYMBOL(dynamic_preempt_schedule);
+EXPORT_SYMBOL(dynamic_preempt_schedule);
+#endif
+#endif
+
+/**
+ * preempt_schedule_notrace - preempt_schedule called by tracing
+ *
+ * The tracing infrastructure uses preempt_enable_notrace to prevent
+ * recursion and tracing preempt enabling caused by the tracing
+ * infrastructure itself. But as tracing can happen in areas coming
+ * from userspace or just about to enter userspace, a preempt enable
+ * can occur before user_exit() is called. This will cause the scheduler
+ * to be called when the system is still in usermode.
+ *
+ * To prevent this, the preempt_enable_notrace will use this function
+ * instead of preempt_schedule() to exit user context if needed before
+ * calling the scheduler.
+ */
+asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
+{
+	enum ctx_state prev_ctx;
+
+	if (likely(!preemptible()))
+		return;
+
+	do {
+		/*
+		 * Because the function tracer can trace preempt_count_sub()
+		 * and it also uses preempt_enable/disable_notrace(), if
+		 * NEED_RESCHED is set, the preempt_enable_notrace() called
+		 * by the function tracer will call this function again and
+		 * cause infinite recursion.
+		 *
+		 * Preemption must be disabled here before the function
+		 * tracer can trace. Break up preempt_disable() into two
+		 * calls. One to disable preemption without fear of being
+		 * traced. The other to still record the preemption latency,
+		 * which can also be traced by the function tracer.
+		 */
+		preempt_disable_notrace();
+		preempt_latency_start(1);
+		/*
+		 * Needs preempt disabled in case user_exit() is traced
+		 * and the tracer calls preempt_enable_notrace() causing
+		 * an infinite recursion.
+		 */
+		prev_ctx = exception_enter();
+		__schedule(SM_PREEMPT);
+		exception_exit(prev_ctx);
+
+		preempt_latency_stop(1);
+		preempt_enable_no_resched_notrace();
+	} while (need_resched());
+}
+EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
+#ifndef preempt_schedule_notrace_dynamic_enabled
+#define preempt_schedule_notrace_dynamic_enabled	preempt_schedule_notrace
+#define preempt_schedule_notrace_dynamic_disabled	NULL
+#endif
+DEFINE_STATIC_CALL(preempt_schedule_notrace, preempt_schedule_notrace_dynamic_enabled);
+EXPORT_STATIC_CALL_TRAMP(preempt_schedule_notrace);
+#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
+static DEFINE_STATIC_KEY_TRUE(sk_dynamic_preempt_schedule_notrace);
+void __sched notrace dynamic_preempt_schedule_notrace(void)
+{
+	if (!static_branch_unlikely(&sk_dynamic_preempt_schedule_notrace))
+		return;
+	preempt_schedule_notrace();
+}
+NOKPROBE_SYMBOL(dynamic_preempt_schedule_notrace);
+EXPORT_SYMBOL(dynamic_preempt_schedule_notrace);
+#endif
+#endif
+
+#endif /* CONFIG_PREEMPTION */
+
+/*
+ * This is the entry point to schedule() from kernel preemption
+ * off of irq context.
+ * Note, that this is called and return with irqs disabled. This will
+ * protect us against recursive calling from irq.
+ */
+asmlinkage __visible void __sched preempt_schedule_irq(void)
+{
+	enum ctx_state prev_state;
+
+	/* Catch callers which need to be fixed */
+	BUG_ON(preempt_count() || !irqs_disabled());
+
+	prev_state = exception_enter();
+
+	do {
+		preempt_disable();
+		local_irq_enable();
+		__schedule(SM_PREEMPT);
+		local_irq_disable();
+		sched_preempt_enable_no_resched();
+	} while (need_resched());
+
+	exception_exit(prev_state);
+}
+
+int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flags,
+			  void *key)
+{
+	WARN_ON_ONCE(IS_ENABLED(CONFIG_SCHED_DEBUG) && wake_flags & ~WF_SYNC);
+	return try_to_wake_up(curr->private, mode, wake_flags);
+}
+EXPORT_SYMBOL(default_wake_function);
+
+static void __setscheduler_prio(struct task_struct *p, int prio)
+{
+	if (dl_prio(prio))
+		p->sched_class = &dl_sched_class;
+	else if (rt_prio(prio))
+		p->sched_class = &rt_sched_class;
+	else
+		p->sched_class = &fair_sched_class;
+
+	p->prio = prio;
+}
+
+#ifdef CONFIG_RT_MUTEXES
+
+static inline int __rt_effective_prio(struct task_struct *pi_task, int prio)
+{
+	if (pi_task)
+		prio = min(prio, pi_task->prio);
+
+	return prio;
+}
+
+static inline int rt_effective_prio(struct task_struct *p, int prio)
+{
+	struct task_struct *pi_task = rt_mutex_get_top_task(p);
+
+	return __rt_effective_prio(pi_task, prio);
+}
+
+/*
+ * rt_mutex_setprio - set the current priority of a task
+ * @p: task to boost
+ * @pi_task: donor task
+ *
+ * This function changes the 'effective' priority of a task. It does
+ * not touch ->normal_prio like __setscheduler().
+ *
+ * Used by the rt_mutex code to implement priority inheritance
+ * logic. Call site only calls if the priority of the task changed.
+ */
+void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
+{
+	int prio, oldprio, queued, running, queue_flag =
+		DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
+	const struct sched_class *prev_class;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	/* XXX used to be waiter->prio, not waiter->task->prio */
+	prio = __rt_effective_prio(pi_task, p->normal_prio);
+
+	/*
+	 * If nothing changed; bail early.
+	 */
+	if (p->pi_top_task == pi_task && prio == p->prio && !dl_prio(prio))
+		return;
+
+	rq = __task_rq_lock(p, &rf);
+	update_rq_clock(rq);
+	/*
+	 * Set under pi_lock && rq->lock, such that the value can be used under
+	 * either lock.
+	 *
+	 * Note that there is loads of tricky to make this pointer cache work
+	 * right. rt_mutex_slowunlock()+rt_mutex_postunlock() work together to
+	 * ensure a task is de-boosted (pi_task is set to NULL) before the
+	 * task is allowed to run again (and can exit). This ensures the pointer
+	 * points to a blocked task -- which guarantees the task is present.
+	 */
+	p->pi_top_task = pi_task;
+
+	/*
+	 * For FIFO/RR we only need to set prio, if that matches we're done.
+	 */
+	if (prio == p->prio && !dl_prio(prio))
+		goto out_unlock;
+
+	/*
+	 * Idle task boosting is a nono in general. There is one
+	 * exception, when PREEMPT_RT and NOHZ is active:
+	 *
+	 * The idle task calls get_next_timer_interrupt() and holds
+	 * the timer wheel base->lock on the CPU and another CPU wants
+	 * to access the timer (probably to cancel it). We can safely
+	 * ignore the boosting request, as the idle CPU runs this code
+	 * with interrupts disabled and will complete the lock
+	 * protected section without being interrupted. So there is no
+	 * real need to boost.
+	 */
+	if (unlikely(p == rq->idle)) {
+		WARN_ON(p != rq->curr);
+		WARN_ON(p->pi_blocked_on);
+		goto out_unlock;
+	}
+
+	trace_sched_pi_setprio(p, pi_task);
+	oldprio = p->prio;
+
+	if (oldprio == prio)
+		queue_flag &= ~DEQUEUE_MOVE;
+
+	prev_class = p->sched_class;
+	queued = task_on_rq_queued(p);
+	running = task_current(rq, p);
+	if (queued)
+		dequeue_task(rq, p, queue_flag);
+	if (running)
+		put_prev_task(rq, p);
+
+	/*
+	 * Boosting condition are:
+	 * 1. -rt task is running and holds mutex A
+	 *      --> -dl task blocks on mutex A
+	 *
+	 * 2. -dl task is running and holds mutex A
+	 *      --> -dl task blocks on mutex A and could preempt the
+	 *          running task
+	 */
+	if (dl_prio(prio)) {
+		if (!dl_prio(p->normal_prio) ||
+		    (pi_task && dl_prio(pi_task->prio) &&
+		     dl_entity_preempt(&pi_task->dl, &p->dl))) {
+			p->dl.pi_se = pi_task->dl.pi_se;
+			queue_flag |= ENQUEUE_REPLENISH;
+		} else {
+			p->dl.pi_se = &p->dl;
+		}
+	} else if (rt_prio(prio)) {
+		if (dl_prio(oldprio))
+			p->dl.pi_se = &p->dl;
+		if (oldprio < prio)
+			queue_flag |= ENQUEUE_HEAD;
+	} else {
+		if (dl_prio(oldprio))
+			p->dl.pi_se = &p->dl;
+		if (rt_prio(oldprio))
+			p->rt.timeout = 0;
+	}
+
+	__setscheduler_prio(p, prio);
+
+	if (queued)
+		enqueue_task(rq, p, queue_flag);
+	if (running)
+		set_next_task(rq, p);
+
+	check_class_changed(rq, p, prev_class, oldprio);
+out_unlock:
+	/* Avoid rq from going away on us: */
+	preempt_disable();
+
+	rq_unpin_lock(rq, &rf);
+	__balance_callbacks(rq);
+	raw_spin_rq_unlock(rq);
+
+	preempt_enable();
+}
+#else
+static inline int rt_effective_prio(struct task_struct *p, int prio)
+{
+	return prio;
+}
+#endif
+
+void set_user_nice(struct task_struct *p, long nice)
+{
+	bool queued, running;
+	int old_prio;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE)
+		return;
+	/*
+	 * We have to be careful, if called from sys_setpriority(),
+	 * the task might be in the middle of scheduling on another CPU.
+	 */
+	rq = task_rq_lock(p, &rf);
+	update_rq_clock(rq);
+
+	/*
+	 * The RT priorities are set via sched_setscheduler(), but we still
+	 * allow the 'normal' nice value to be set - but as expected
+	 * it won't have any effect on scheduling until the task is
+	 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
+	 */
+	if (task_has_dl_policy(p) || task_has_rt_policy(p)) {
+		p->static_prio = NICE_TO_PRIO(nice);
+		goto out_unlock;
+	}
+	queued = task_on_rq_queued(p);
+	running = task_current(rq, p);
+	if (queued)
+		dequeue_task(rq, p, DEQUEUE_SAVE | DEQUEUE_NOCLOCK);
+	if (running)
+		put_prev_task(rq, p);
+
+	p->static_prio = NICE_TO_PRIO(nice);
+	set_load_weight(p, true);
+	old_prio = p->prio;
+	p->prio = effective_prio(p);
+
+	if (queued)
+		enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
+	if (running)
+		set_next_task(rq, p);
+
+	/*
+	 * If the task increased its priority or is running and
+	 * lowered its priority, then reschedule its CPU:
+	 */
+	p->sched_class->prio_changed(rq, p, old_prio);
+
+out_unlock:
+	task_rq_unlock(rq, p, &rf);
+}
+EXPORT_SYMBOL(set_user_nice);
+
+/*
+ * is_nice_reduction - check if nice value is an actual reduction
+ *
+ * Similar to can_nice() but does not perform a capability check.
+ *
+ * @p: task
+ * @nice: nice value
+ */
+static bool is_nice_reduction(const struct task_struct *p, const int nice)
+{
+	/* Convert nice value [19,-20] to rlimit style value [1,40]: */
+	int nice_rlim = nice_to_rlimit(nice);
+
+	return (nice_rlim <= task_rlimit(p, RLIMIT_NICE));
+}
+
+/*
+ * can_nice - check if a task can reduce its nice value
+ * @p: task
+ * @nice: nice value
+ */
+int can_nice(const struct task_struct *p, const int nice)
+{
+	return is_nice_reduction(p, nice) || capable(CAP_SYS_NICE);
+}
+
+#ifdef __ARCH_WANT_SYS_NICE
+
+/*
+ * sys_nice - change the priority of the current process.
+ * @increment: priority increment
+ *
+ * sys_setpriority is a more generic, but much slower function that
+ * does similar things.
+ */
+SYSCALL_DEFINE1(nice, int, increment)
+{
+	long nice, retval;
+
+	/*
+	 * Setpriority might change our priority at the same moment.
+	 * We don't have to worry. Conceptually one call occurs first
+	 * and we have a single winner.
+	 */
+	increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH);
+	nice = task_nice(current) + increment;
+
+	nice = clamp_val(nice, MIN_NICE, MAX_NICE);
+	if (increment < 0 && !can_nice(current, nice))
+		return -EPERM;
+
+	retval = security_task_setnice(current, nice);
+	if (retval)
+		return retval;
+
+	set_user_nice(current, nice);
+	return 0;
+}
+
+#endif
+
+/**
+ * task_prio - return the priority value of a given task.
+ * @p: the task in question.
+ *
+ * Return: The priority value as seen by users in /proc.
+ *
+ * sched policy         return value   kernel prio    user prio/nice
+ *
+ * normal, batch, idle     [0 ... 39]  [100 ... 139]          0/[-20 ... 19]
+ * fifo, rr             [-2 ... -100]     [98 ... 0]  [1 ... 99]
+ * deadline                     -101             -1           0
+ */
+int task_prio(const struct task_struct *p)
+{
+	return p->prio - MAX_RT_PRIO;
+}
+
+/**
+ * idle_cpu - is a given CPU idle currently?
+ * @cpu: the processor in question.
+ *
+ * Return: 1 if the CPU is currently idle. 0 otherwise.
+ */
+int idle_cpu(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (rq->curr != rq->idle)
+		return 0;
+
+	if (rq->nr_running)
+		return 0;
+
+#ifdef CONFIG_SMP
+	if (rq->ttwu_pending)
+		return 0;
+#endif
+
+	return 1;
+}
+
+/**
+ * available_idle_cpu - is a given CPU idle for enqueuing work.
+ * @cpu: the CPU in question.
+ *
+ * Return: 1 if the CPU is currently idle. 0 otherwise.
+ */
+int available_idle_cpu(int cpu)
+{
+	if (!idle_cpu(cpu))
+		return 0;
+
+	if (vcpu_is_preempted(cpu))
+		return 0;
+
+	return 1;
+}
+
+/**
+ * idle_task - return the idle task for a given CPU.
+ * @cpu: the processor in question.
+ *
+ * Return: The idle task for the CPU @cpu.
+ */
+struct task_struct *idle_task(int cpu)
+{
+	return cpu_rq(cpu)->idle;
+}
+
+#ifdef CONFIG_SMP
+/*
+ * This function computes an effective utilization for the given CPU, to be
+ * used for frequency selection given the linear relation: f = u * f_max.
+ *
+ * The scheduler tracks the following metrics:
+ *
+ *   cpu_util_{cfs,rt,dl,irq}()
+ *   cpu_bw_dl()
+ *
+ * Where the cfs,rt and dl util numbers are tracked with the same metric and
+ * synchronized windows and are thus directly comparable.
+ *
+ * The cfs,rt,dl utilization are the running times measured with rq->clock_task
+ * which excludes things like IRQ and steal-time. These latter are then accrued
+ * in the irq utilization.
+ *
+ * The DL bandwidth number otoh is not a measured metric but a value computed
+ * based on the task model parameters and gives the minimal utilization
+ * required to meet deadlines.
+ */
+unsigned long effective_cpu_util(int cpu, unsigned long util_cfs,
+				 enum cpu_util_type type,
+				 struct task_struct *p)
+{
+	unsigned long dl_util, util, irq, max;
+	struct rq *rq = cpu_rq(cpu);
+
+	max = arch_scale_cpu_capacity(cpu);
+
+	if (!uclamp_is_used() &&
+	    type == FREQUENCY_UTIL && rt_rq_is_runnable(&rq->rt)) {
+		return max;
+	}
+
+	/*
+	 * Early check to see if IRQ/steal time saturates the CPU, can be
+	 * because of inaccuracies in how we track these -- see
+	 * update_irq_load_avg().
+	 */
+	irq = cpu_util_irq(rq);
+	if (unlikely(irq >= max))
+		return max;
+
+	/*
+	 * Because the time spend on RT/DL tasks is visible as 'lost' time to
+	 * CFS tasks and we use the same metric to track the effective
+	 * utilization (PELT windows are synchronized) we can directly add them
+	 * to obtain the CPU's actual utilization.
+	 *
+	 * CFS and RT utilization can be boosted or capped, depending on
+	 * utilization clamp constraints requested by currently RUNNABLE
+	 * tasks.
+	 * When there are no CFS RUNNABLE tasks, clamps are released and
+	 * frequency will be gracefully reduced with the utilization decay.
+	 */
+	util = util_cfs + cpu_util_rt(rq);
+	if (type == FREQUENCY_UTIL)
+		util = uclamp_rq_util_with(rq, util, p);
+
+	dl_util = cpu_util_dl(rq);
+
+	/*
+	 * For frequency selection we do not make cpu_util_dl() a permanent part
+	 * of this sum because we want to use cpu_bw_dl() later on, but we need
+	 * to check if the CFS+RT+DL sum is saturated (ie. no idle time) such
+	 * that we select f_max when there is no idle time.
+	 *
+	 * NOTE: numerical errors or stop class might cause us to not quite hit
+	 * saturation when we should -- something for later.
+	 */
+	if (util + dl_util >= max)
+		return max;
+
+	/*
+	 * OTOH, for energy computation we need the estimated running time, so
+	 * include util_dl and ignore dl_bw.
+	 */
+	if (type == ENERGY_UTIL)
+		util += dl_util;
+
+	/*
+	 * There is still idle time; further improve the number by using the
+	 * irq metric. Because IRQ/steal time is hidden from the task clock we
+	 * need to scale the task numbers:
+	 *
+	 *              max - irq
+	 *   U' = irq + --------- * U
+	 *                 max
+	 */
+	util = scale_irq_capacity(util, irq, max);
+	util += irq;
+
+	/*
+	 * Bandwidth required by DEADLINE must always be granted while, for
+	 * FAIR and RT, we use blocked utilization of IDLE CPUs as a mechanism
+	 * to gracefully reduce the frequency when no tasks show up for longer
+	 * periods of time.
+	 *
+	 * Ideally we would like to set bw_dl as min/guaranteed freq and util +
+	 * bw_dl as requested freq. However, cpufreq is not yet ready for such
+	 * an interface. So, we only do the latter for now.
+	 */
+	if (type == FREQUENCY_UTIL)
+		util += cpu_bw_dl(rq);
+
+	return min(max, util);
+}
+
+unsigned long sched_cpu_util(int cpu)
+{
+	return effective_cpu_util(cpu, cpu_util_cfs(cpu), ENERGY_UTIL, NULL);
+}
+#endif /* CONFIG_SMP */
+
+/**
+ * find_process_by_pid - find a process with a matching PID value.
+ * @pid: the pid in question.
+ *
+ * The task of @pid, if found. %NULL otherwise.
+ */
+static struct task_struct *find_process_by_pid(pid_t pid)
+{
+	return pid ? find_task_by_vpid(pid) : current;
+}
+
+/*
+ * sched_setparam() passes in -1 for its policy, to let the functions
+ * it calls know not to change it.
+ */
+#define SETPARAM_POLICY	-1
+
+static void __setscheduler_params(struct task_struct *p,
+		const struct sched_attr *attr)
+{
+	int policy = attr->sched_policy;
+
+	if (policy == SETPARAM_POLICY)
+		policy = p->policy;
+
+	p->policy = policy;
+
+	if (dl_policy(policy))
+		__setparam_dl(p, attr);
+	else if (fair_policy(policy))
+		p->static_prio = NICE_TO_PRIO(attr->sched_nice);
+
+	/*
+	 * __sched_setscheduler() ensures attr->sched_priority == 0 when
+	 * !rt_policy. Always setting this ensures that things like
+	 * getparam()/getattr() don't report silly values for !rt tasks.
+	 */
+	p->rt_priority = attr->sched_priority;
+	p->normal_prio = normal_prio(p);
+	set_load_weight(p, true);
+}
+
+/*
+ * Check the target process has a UID that matches the current process's:
+ */
+static bool check_same_owner(struct task_struct *p)
+{
+	const struct cred *cred = current_cred(), *pcred;
+	bool match;
+
+	rcu_read_lock();
+	pcred = __task_cred(p);
+	match = (uid_eq(cred->euid, pcred->euid) ||
+		 uid_eq(cred->euid, pcred->uid));
+	rcu_read_unlock();
+	return match;
+}
+
+/*
+ * Allow unprivileged RT tasks to decrease priority.
+ * Only issue a capable test if needed and only once to avoid an audit
+ * event on permitted non-privileged operations:
+ */
+static int user_check_sched_setscheduler(struct task_struct *p,
+					 const struct sched_attr *attr,
+					 int policy, int reset_on_fork)
+{
+	if (fair_policy(policy)) {
+		if (attr->sched_nice < task_nice(p) &&
+		    !is_nice_reduction(p, attr->sched_nice))
+			goto req_priv;
+	}
+
+	if (rt_policy(policy)) {
+		unsigned long rlim_rtprio = task_rlimit(p, RLIMIT_RTPRIO);
+
+		/* Can't set/change the rt policy: */
+		if (policy != p->policy && !rlim_rtprio)
+			goto req_priv;
+
+		/* Can't increase priority: */
+		if (attr->sched_priority > p->rt_priority &&
+		    attr->sched_priority > rlim_rtprio)
+			goto req_priv;
+	}
+
+	/*
+	 * Can't set/change SCHED_DEADLINE policy at all for now
+	 * (safest behavior); in the future we would like to allow
+	 * unprivileged DL tasks to increase their relative deadline
+	 * or reduce their runtime (both ways reducing utilization)
+	 */
+	if (dl_policy(policy))
+		goto req_priv;
+
+	/*
+	 * Treat SCHED_IDLE as nice 20. Only allow a switch to
+	 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
+	 */
+	if (task_has_idle_policy(p) && !idle_policy(policy)) {
+		if (!is_nice_reduction(p, task_nice(p)))
+			goto req_priv;
+	}
+
+	/* Can't change other user's priorities: */
+	if (!check_same_owner(p))
+		goto req_priv;
+
+	/* Normal users shall not reset the sched_reset_on_fork flag: */
+	if (p->sched_reset_on_fork && !reset_on_fork)
+		goto req_priv;
+
+	return 0;
+
+req_priv:
+	if (!capable(CAP_SYS_NICE))
+		return -EPERM;
+
+	return 0;
+}
+
+static int __sched_setscheduler(struct task_struct *p,
+				const struct sched_attr *attr,
+				bool user, bool pi)
+{
+	int oldpolicy = -1, policy = attr->sched_policy;
+	int retval, oldprio, newprio, queued, running;
+	const struct sched_class *prev_class;
+	struct balance_callback *head;
+	struct rq_flags rf;
+	int reset_on_fork;
+	int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
+	struct rq *rq;
+	bool cpuset_locked = false;
+
+	/* The pi code expects interrupts enabled */
+	BUG_ON(pi && in_interrupt());
+recheck:
+	/* Double check policy once rq lock held: */
+	if (policy < 0) {
+		reset_on_fork = p->sched_reset_on_fork;
+		policy = oldpolicy = p->policy;
+	} else {
+		reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK);
+
+		if (!valid_policy(policy))
+			return -EINVAL;
+	}
+
+	if (attr->sched_flags & ~(SCHED_FLAG_ALL | SCHED_FLAG_SUGOV))
+		return -EINVAL;
+
+	/*
+	 * Valid priorities for SCHED_FIFO and SCHED_RR are
+	 * 1..MAX_RT_PRIO-1, valid priority for SCHED_NORMAL,
+	 * SCHED_BATCH and SCHED_IDLE is 0.
+	 */
+	if (attr->sched_priority > MAX_RT_PRIO-1)
+		return -EINVAL;
+	if ((dl_policy(policy) && !__checkparam_dl(attr)) ||
+	    (rt_policy(policy) != (attr->sched_priority != 0)))
+		return -EINVAL;
+
+	if (user) {
+		retval = user_check_sched_setscheduler(p, attr, policy, reset_on_fork);
+		if (retval)
+			return retval;
+
+		if (attr->sched_flags & SCHED_FLAG_SUGOV)
+			return -EINVAL;
+
+		retval = security_task_setscheduler(p);
+		if (retval)
+			return retval;
+	}
+
+	/* Update task specific "requested" clamps */
+	if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP) {
+		retval = uclamp_validate(p, attr);
+		if (retval)
+			return retval;
+	}
+
+	/*
+	 * SCHED_DEADLINE bandwidth accounting relies on stable cpusets
+	 * information.
+	 */
+	if (dl_policy(policy) || dl_policy(p->policy)) {
+		cpuset_locked = true;
+		cpuset_lock();
+	}
+
+	/*
+	 * Make sure no PI-waiters arrive (or leave) while we are
+	 * changing the priority of the task:
+	 *
+	 * To be able to change p->policy safely, the appropriate
+	 * runqueue lock must be held.
+	 */
+	rq = task_rq_lock(p, &rf);
+	update_rq_clock(rq);
+
+	/*
+	 * Changing the policy of the stop threads its a very bad idea:
+	 */
+	if (p == rq->stop) {
+		retval = -EINVAL;
+		goto unlock;
+	}
+
+	/*
+	 * If not changing anything there's no need to proceed further,
+	 * but store a possible modification of reset_on_fork.
+	 */
+	if (unlikely(policy == p->policy)) {
+		if (fair_policy(policy) && attr->sched_nice != task_nice(p))
+			goto change;
+		if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
+			goto change;
+		if (dl_policy(policy) && dl_param_changed(p, attr))
+			goto change;
+		if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)
+			goto change;
+
+		p->sched_reset_on_fork = reset_on_fork;
+		retval = 0;
+		goto unlock;
+	}
+change:
+
+	if (user) {
+#ifdef CONFIG_RT_GROUP_SCHED
+		/*
+		 * Do not allow realtime tasks into groups that have no runtime
+		 * assigned.
+		 */
+		if (rt_bandwidth_enabled() && rt_policy(policy) &&
+				task_group(p)->rt_bandwidth.rt_runtime == 0 &&
+				!task_group_is_autogroup(task_group(p))) {
+			retval = -EPERM;
+			goto unlock;
+		}
+#endif
+#ifdef CONFIG_SMP
+		if (dl_bandwidth_enabled() && dl_policy(policy) &&
+				!(attr->sched_flags & SCHED_FLAG_SUGOV)) {
+			cpumask_t *span = rq->rd->span;
+
+			/*
+			 * Don't allow tasks with an affinity mask smaller than
+			 * the entire root_domain to become SCHED_DEADLINE. We
+			 * will also fail if there's no bandwidth available.
+			 */
+			if (!cpumask_subset(span, p->cpus_ptr) ||
+			    rq->rd->dl_bw.bw == 0) {
+				retval = -EPERM;
+				goto unlock;
+			}
+		}
+#endif
+	}
+
+	/* Re-check policy now with rq lock held: */
+	if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
+		policy = oldpolicy = -1;
+		task_rq_unlock(rq, p, &rf);
+		if (cpuset_locked)
+			cpuset_unlock();
+		goto recheck;
+	}
+
+	/*
+	 * If setscheduling to SCHED_DEADLINE (or changing the parameters
+	 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
+	 * is available.
+	 */
+	if ((dl_policy(policy) || dl_task(p)) && sched_dl_overflow(p, policy, attr)) {
+		retval = -EBUSY;
+		goto unlock;
+	}
+
+	p->sched_reset_on_fork = reset_on_fork;
+	oldprio = p->prio;
+
+	newprio = __normal_prio(policy, attr->sched_priority, attr->sched_nice);
+	if (pi) {
+		/*
+		 * Take priority boosted tasks into account. If the new
+		 * effective priority is unchanged, we just store the new
+		 * normal parameters and do not touch the scheduler class and
+		 * the runqueue. This will be done when the task deboost
+		 * itself.
+		 */
+		newprio = rt_effective_prio(p, newprio);
+		if (newprio == oldprio)
+			queue_flags &= ~DEQUEUE_MOVE;
+	}
+
+	queued = task_on_rq_queued(p);
+	running = task_current(rq, p);
+	if (queued)
+		dequeue_task(rq, p, queue_flags);
+	if (running)
+		put_prev_task(rq, p);
+
+	prev_class = p->sched_class;
+
+	if (!(attr->sched_flags & SCHED_FLAG_KEEP_PARAMS)) {
+		__setscheduler_params(p, attr);
+		__setscheduler_prio(p, newprio);
+	}
+	__setscheduler_uclamp(p, attr);
+
+	if (queued) {
+		/*
+		 * We enqueue to tail when the priority of a task is
+		 * increased (user space view).
+		 */
+		if (oldprio < p->prio)
+			queue_flags |= ENQUEUE_HEAD;
+
+		enqueue_task(rq, p, queue_flags);
+	}
+	if (running)
+		set_next_task(rq, p);
+
+	check_class_changed(rq, p, prev_class, oldprio);
+
+	/* Avoid rq from going away on us: */
+	preempt_disable();
+	head = splice_balance_callbacks(rq);
+	task_rq_unlock(rq, p, &rf);
+
+	if (pi) {
+		if (cpuset_locked)
+			cpuset_unlock();
+		rt_mutex_adjust_pi(p);
+	}
+
+	/* Run balance callbacks after we've adjusted the PI chain: */
+	balance_callbacks(rq, head);
+	preempt_enable();
+
+	return 0;
+
+unlock:
+	task_rq_unlock(rq, p, &rf);
+	if (cpuset_locked)
+		cpuset_unlock();
+	return retval;
+}
+
+static int _sched_setscheduler(struct task_struct *p, int policy,
+			       const struct sched_param *param, bool check)
+{
+	struct sched_attr attr = {
+		.sched_policy   = policy,
+		.sched_priority = param->sched_priority,
+		.sched_nice	= PRIO_TO_NICE(p->static_prio),
+	};
+
+	/* Fixup the legacy SCHED_RESET_ON_FORK hack. */
+	if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) {
+		attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
+		policy &= ~SCHED_RESET_ON_FORK;
+		attr.sched_policy = policy;
+	}
+
+	return __sched_setscheduler(p, &attr, check, true);
+}
+/**
+ * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
+ * @p: the task in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ *
+ * Use sched_set_fifo(), read its comment.
+ *
+ * Return: 0 on success. An error code otherwise.
+ *
+ * NOTE that the task may be already dead.
+ */
+int sched_setscheduler(struct task_struct *p, int policy,
+		       const struct sched_param *param)
+{
+	return _sched_setscheduler(p, policy, param, true);
+}
+
+int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
+{
+	return __sched_setscheduler(p, attr, true, true);
+}
+
+int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr)
+{
+	return __sched_setscheduler(p, attr, false, true);
+}
+EXPORT_SYMBOL_GPL(sched_setattr_nocheck);
+
+/**
+ * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
+ * @p: the task in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ *
+ * Just like sched_setscheduler, only don't bother checking if the
+ * current context has permission.  For example, this is needed in
+ * stop_machine(): we create temporary high priority worker threads,
+ * but our caller might not have that capability.
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+int sched_setscheduler_nocheck(struct task_struct *p, int policy,
+			       const struct sched_param *param)
+{
+	return _sched_setscheduler(p, policy, param, false);
+}
+
+/*
+ * SCHED_FIFO is a broken scheduler model; that is, it is fundamentally
+ * incapable of resource management, which is the one thing an OS really should
+ * be doing.
+ *
+ * This is of course the reason it is limited to privileged users only.
+ *
+ * Worse still; it is fundamentally impossible to compose static priority
+ * workloads. You cannot take two correctly working static prio workloads
+ * and smash them together and still expect them to work.
+ *
+ * For this reason 'all' FIFO tasks the kernel creates are basically at:
+ *
+ *   MAX_RT_PRIO / 2
+ *
+ * The administrator _MUST_ configure the system, the kernel simply doesn't
+ * know enough information to make a sensible choice.
+ */
+void sched_set_fifo(struct task_struct *p)
+{
+	struct sched_param sp = { .sched_priority = MAX_RT_PRIO / 2 };
+	WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
+}
+EXPORT_SYMBOL_GPL(sched_set_fifo);
+
+/*
+ * For when you don't much care about FIFO, but want to be above SCHED_NORMAL.
+ */
+void sched_set_fifo_low(struct task_struct *p)
+{
+	struct sched_param sp = { .sched_priority = 1 };
+	WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
+}
+EXPORT_SYMBOL_GPL(sched_set_fifo_low);
+
+void sched_set_normal(struct task_struct *p, int nice)
+{
+	struct sched_attr attr = {
+		.sched_policy = SCHED_NORMAL,
+		.sched_nice = nice,
+	};
+	WARN_ON_ONCE(sched_setattr_nocheck(p, &attr) != 0);
+}
+EXPORT_SYMBOL_GPL(sched_set_normal);
+
+static int
+do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
+{
+	struct sched_param lparam;
+	struct task_struct *p;
+	int retval;
+
+	if (!param || pid < 0)
+		return -EINVAL;
+	if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
+		return -EFAULT;
+
+	rcu_read_lock();
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (likely(p))
+		get_task_struct(p);
+	rcu_read_unlock();
+
+	if (likely(p)) {
+		retval = sched_setscheduler(p, policy, &lparam);
+		put_task_struct(p);
+	}
+
+	return retval;
+}
+
+/*
+ * Mimics kernel/events/core.c perf_copy_attr().
+ */
+static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *attr)
+{
+	u32 size;
+	int ret;
+
+	/* Zero the full structure, so that a short copy will be nice: */
+	memset(attr, 0, sizeof(*attr));
+
+	ret = get_user(size, &uattr->size);
+	if (ret)
+		return ret;
+
+	/* ABI compatibility quirk: */
+	if (!size)
+		size = SCHED_ATTR_SIZE_VER0;
+	if (size < SCHED_ATTR_SIZE_VER0 || size > PAGE_SIZE)
+		goto err_size;
+
+	ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
+	if (ret) {
+		if (ret == -E2BIG)
+			goto err_size;
+		return ret;
+	}
+
+	if ((attr->sched_flags & SCHED_FLAG_UTIL_CLAMP) &&
+	    size < SCHED_ATTR_SIZE_VER1)
+		return -EINVAL;
+
+	/*
+	 * XXX: Do we want to be lenient like existing syscalls; or do we want
+	 * to be strict and return an error on out-of-bounds values?
+	 */
+	attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE);
+
+	return 0;
+
+err_size:
+	put_user(sizeof(*attr), &uattr->size);
+	return -E2BIG;
+}
+
+static void get_params(struct task_struct *p, struct sched_attr *attr)
+{
+	if (task_has_dl_policy(p))
+		__getparam_dl(p, attr);
+	else if (task_has_rt_policy(p))
+		attr->sched_priority = p->rt_priority;
+	else
+		attr->sched_nice = task_nice(p);
+}
+
+/**
+ * sys_sched_setscheduler - set/change the scheduler policy and RT priority
+ * @pid: the pid in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, struct sched_param __user *, param)
+{
+	if (policy < 0)
+		return -EINVAL;
+
+	return do_sched_setscheduler(pid, policy, param);
+}
+
+/**
+ * sys_sched_setparam - set/change the RT priority of a thread
+ * @pid: the pid in question.
+ * @param: structure containing the new RT priority.
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
+{
+	return do_sched_setscheduler(pid, SETPARAM_POLICY, param);
+}
+
+/**
+ * sys_sched_setattr - same as above, but with extended sched_attr
+ * @pid: the pid in question.
+ * @uattr: structure containing the extended parameters.
+ * @flags: for future extension.
+ */
+SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
+			       unsigned int, flags)
+{
+	struct sched_attr attr;
+	struct task_struct *p;
+	int retval;
+
+	if (!uattr || pid < 0 || flags)
+		return -EINVAL;
+
+	retval = sched_copy_attr(uattr, &attr);
+	if (retval)
+		return retval;
+
+	if ((int)attr.sched_policy < 0)
+		return -EINVAL;
+	if (attr.sched_flags & SCHED_FLAG_KEEP_POLICY)
+		attr.sched_policy = SETPARAM_POLICY;
+
+	rcu_read_lock();
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (likely(p))
+		get_task_struct(p);
+	rcu_read_unlock();
+
+	if (likely(p)) {
+		if (attr.sched_flags & SCHED_FLAG_KEEP_PARAMS)
+			get_params(p, &attr);
+		retval = sched_setattr(p, &attr);
+		put_task_struct(p);
+	}
+
+	return retval;
+}
+
+/**
+ * sys_sched_getscheduler - get the policy (scheduling class) of a thread
+ * @pid: the pid in question.
+ *
+ * Return: On success, the policy of the thread. Otherwise, a negative error
+ * code.
+ */
+SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
+{
+	struct task_struct *p;
+	int retval;
+
+	if (pid < 0)
+		return -EINVAL;
+
+	retval = -ESRCH;
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	if (p) {
+		retval = security_task_getscheduler(p);
+		if (!retval)
+			retval = p->policy
+				| (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
+	}
+	rcu_read_unlock();
+	return retval;
+}
+
+/**
+ * sys_sched_getparam - get the RT priority of a thread
+ * @pid: the pid in question.
+ * @param: structure containing the RT priority.
+ *
+ * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
+ * code.
+ */
+SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
+{
+	struct sched_param lp = { .sched_priority = 0 };
+	struct task_struct *p;
+	int retval;
+
+	if (!param || pid < 0)
+		return -EINVAL;
+
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	retval = -ESRCH;
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	if (task_has_rt_policy(p))
+		lp.sched_priority = p->rt_priority;
+	rcu_read_unlock();
+
+	/*
+	 * This one might sleep, we cannot do it with a spinlock held ...
+	 */
+	retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
+
+	return retval;
+
+out_unlock:
+	rcu_read_unlock();
+	return retval;
+}
+
+/*
+ * Copy the kernel size attribute structure (which might be larger
+ * than what user-space knows about) to user-space.
+ *
+ * Note that all cases are valid: user-space buffer can be larger or
+ * smaller than the kernel-space buffer. The usual case is that both
+ * have the same size.
+ */
+static int
+sched_attr_copy_to_user(struct sched_attr __user *uattr,
+			struct sched_attr *kattr,
+			unsigned int usize)
+{
+	unsigned int ksize = sizeof(*kattr);
+
+	if (!access_ok(uattr, usize))
+		return -EFAULT;
+
+	/*
+	 * sched_getattr() ABI forwards and backwards compatibility:
+	 *
+	 * If usize == ksize then we just copy everything to user-space and all is good.
+	 *
+	 * If usize < ksize then we only copy as much as user-space has space for,
+	 * this keeps ABI compatibility as well. We skip the rest.
+	 *
+	 * If usize > ksize then user-space is using a newer version of the ABI,
+	 * which part the kernel doesn't know about. Just ignore it - tooling can
+	 * detect the kernel's knowledge of attributes from the attr->size value
+	 * which is set to ksize in this case.
+	 */
+	kattr->size = min(usize, ksize);
+
+	if (copy_to_user(uattr, kattr, kattr->size))
+		return -EFAULT;
+
+	return 0;
+}
+
+/**
+ * sys_sched_getattr - similar to sched_getparam, but with sched_attr
+ * @pid: the pid in question.
+ * @uattr: structure containing the extended parameters.
+ * @usize: sizeof(attr) for fwd/bwd comp.
+ * @flags: for future extension.
+ */
+SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
+		unsigned int, usize, unsigned int, flags)
+{
+	struct sched_attr kattr = { };
+	struct task_struct *p;
+	int retval;
+
+	if (!uattr || pid < 0 || usize > PAGE_SIZE ||
+	    usize < SCHED_ATTR_SIZE_VER0 || flags)
+		return -EINVAL;
+
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	retval = -ESRCH;
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	kattr.sched_policy = p->policy;
+	if (p->sched_reset_on_fork)
+		kattr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
+	get_params(p, &kattr);
+	kattr.sched_flags &= SCHED_FLAG_ALL;
+
+#ifdef CONFIG_UCLAMP_TASK
+	/*
+	 * This could race with another potential updater, but this is fine
+	 * because it'll correctly read the old or the new value. We don't need
+	 * to guarantee who wins the race as long as it doesn't return garbage.
+	 */
+	kattr.sched_util_min = p->uclamp_req[UCLAMP_MIN].value;
+	kattr.sched_util_max = p->uclamp_req[UCLAMP_MAX].value;
+#endif
+
+	rcu_read_unlock();
+
+	return sched_attr_copy_to_user(uattr, &kattr, usize);
+
+out_unlock:
+	rcu_read_unlock();
+	return retval;
+}
+
+#ifdef CONFIG_SMP
+int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask)
+{
+	int ret = 0;
+
+	/*
+	 * If the task isn't a deadline task or admission control is
+	 * disabled then we don't care about affinity changes.
+	 */
+	if (!task_has_dl_policy(p) || !dl_bandwidth_enabled())
+		return 0;
+
+	/*
+	 * Since bandwidth control happens on root_domain basis,
+	 * if admission test is enabled, we only admit -deadline
+	 * tasks allowed to run on all the CPUs in the task's
+	 * root_domain.
+	 */
+	rcu_read_lock();
+	if (!cpumask_subset(task_rq(p)->rd->span, mask))
+		ret = -EBUSY;
+	rcu_read_unlock();
+	return ret;
+}
+#endif
+
+static int
+__sched_setaffinity(struct task_struct *p, const struct cpumask *mask)
+{
+	int retval;
+	cpumask_var_t cpus_allowed, new_mask;
+
+	if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL))
+		return -ENOMEM;
+
+	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
+		retval = -ENOMEM;
+		goto out_free_cpus_allowed;
+	}
+
+	cpuset_cpus_allowed(p, cpus_allowed);
+	cpumask_and(new_mask, mask, cpus_allowed);
+
+	retval = dl_task_check_affinity(p, new_mask);
+	if (retval)
+		goto out_free_new_mask;
+again:
+	retval = __set_cpus_allowed_ptr(p, new_mask, SCA_CHECK | SCA_USER);
+	if (retval)
+		goto out_free_new_mask;
+
+	cpuset_cpus_allowed(p, cpus_allowed);
+	if (!cpumask_subset(new_mask, cpus_allowed)) {
+		/*
+		 * We must have raced with a concurrent cpuset update.
+		 * Just reset the cpumask to the cpuset's cpus_allowed.
+		 */
+		cpumask_copy(new_mask, cpus_allowed);
+		goto again;
+	}
+
+out_free_new_mask:
+	free_cpumask_var(new_mask);
+out_free_cpus_allowed:
+	free_cpumask_var(cpus_allowed);
+	return retval;
+}
+
+long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+{
+	struct task_struct *p;
+	int retval;
+
+	rcu_read_lock();
+
+	p = find_process_by_pid(pid);
+	if (!p) {
+		rcu_read_unlock();
+		return -ESRCH;
+	}
+
+	/* Prevent p going away */
+	get_task_struct(p);
+	rcu_read_unlock();
+
+	if (p->flags & PF_NO_SETAFFINITY) {
+		retval = -EINVAL;
+		goto out_put_task;
+	}
+
+	if (!check_same_owner(p)) {
+		rcu_read_lock();
+		if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
+			rcu_read_unlock();
+			retval = -EPERM;
+			goto out_put_task;
+		}
+		rcu_read_unlock();
+	}
+
+	retval = security_task_setscheduler(p);
+	if (retval)
+		goto out_put_task;
+
+	retval = __sched_setaffinity(p, in_mask);
+out_put_task:
+	put_task_struct(p);
+	return retval;
+}
+
+static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
+			     struct cpumask *new_mask)
+{
+	if (len < cpumask_size())
+		cpumask_clear(new_mask);
+	else if (len > cpumask_size())
+		len = cpumask_size();
+
+	return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
+}
+
+/**
+ * sys_sched_setaffinity - set the CPU affinity of a process
+ * @pid: pid of the process
+ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
+ * @user_mask_ptr: user-space pointer to the new CPU mask
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
+		unsigned long __user *, user_mask_ptr)
+{
+	cpumask_var_t new_mask;
+	int retval;
+
+	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
+	if (retval == 0)
+		retval = sched_setaffinity(pid, new_mask);
+	free_cpumask_var(new_mask);
+	return retval;
+}
+
+long sched_getaffinity(pid_t pid, struct cpumask *mask)
+{
+	struct task_struct *p;
+	unsigned long flags;
+	int retval;
+
+	rcu_read_lock();
+
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	cpumask_and(mask, &p->cpus_mask, cpu_active_mask);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+
+out_unlock:
+	rcu_read_unlock();
+
+	return retval;
+}
+
+/**
+ * sys_sched_getaffinity - get the CPU affinity of a process
+ * @pid: pid of the process
+ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
+ * @user_mask_ptr: user-space pointer to hold the current CPU mask
+ *
+ * Return: size of CPU mask copied to user_mask_ptr on success. An
+ * error code otherwise.
+ */
+SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
+		unsigned long __user *, user_mask_ptr)
+{
+	int ret;
+	cpumask_var_t mask;
+
+	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
+		return -EINVAL;
+	if (len & (sizeof(unsigned long)-1))
+		return -EINVAL;
+
+	if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	ret = sched_getaffinity(pid, mask);
+	if (ret == 0) {
+		unsigned int retlen = min(len, cpumask_size());
+
+		if (copy_to_user(user_mask_ptr, cpumask_bits(mask), retlen))
+			ret = -EFAULT;
+		else
+			ret = retlen;
+	}
+	free_cpumask_var(mask);
+
+	return ret;
+}
+
+static void do_sched_yield(void)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = this_rq_lock_irq(&rf);
+
+	schedstat_inc(rq->yld_count);
+	current->sched_class->yield_task(rq);
+
+	preempt_disable();
+	rq_unlock_irq(rq, &rf);
+	sched_preempt_enable_no_resched();
+
+	schedule();
+}
+
+/**
+ * sys_sched_yield - yield the current processor to other threads.
+ *
+ * This function yields the current CPU to other tasks. If there are no
+ * other threads running on this CPU then this function will return.
+ *
+ * Return: 0.
+ */
+SYSCALL_DEFINE0(sched_yield)
+{
+	do_sched_yield();
+	return 0;
+}
+
+#if !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC)
+int __sched __cond_resched(void)
+{
+	if (should_resched(0)) {
+		preempt_schedule_common();
+		return 1;
+	}
+	/*
+	 * In preemptible kernels, ->rcu_read_lock_nesting tells the tick
+	 * whether the current CPU is in an RCU read-side critical section,
+	 * so the tick can report quiescent states even for CPUs looping
+	 * in kernel context.  In contrast, in non-preemptible kernels,
+	 * RCU readers leave no in-memory hints, which means that CPU-bound
+	 * processes executing in kernel context might never report an
+	 * RCU quiescent state.  Therefore, the following code causes
+	 * cond_resched() to report a quiescent state, but only when RCU
+	 * is in urgent need of one.
+	 */
+#ifndef CONFIG_PREEMPT_RCU
+	rcu_all_qs();
+#endif
+	return 0;
+}
+EXPORT_SYMBOL(__cond_resched);
+#endif
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
+#define cond_resched_dynamic_enabled	__cond_resched
+#define cond_resched_dynamic_disabled	((void *)&__static_call_return0)
+DEFINE_STATIC_CALL_RET0(cond_resched, __cond_resched);
+EXPORT_STATIC_CALL_TRAMP(cond_resched);
+
+#define might_resched_dynamic_enabled	__cond_resched
+#define might_resched_dynamic_disabled	((void *)&__static_call_return0)
+DEFINE_STATIC_CALL_RET0(might_resched, __cond_resched);
+EXPORT_STATIC_CALL_TRAMP(might_resched);
+#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
+static DEFINE_STATIC_KEY_FALSE(sk_dynamic_cond_resched);
+int __sched dynamic_cond_resched(void)
+{
+	if (!static_branch_unlikely(&sk_dynamic_cond_resched))
+		return 0;
+	return __cond_resched();
+}
+EXPORT_SYMBOL(dynamic_cond_resched);
+
+static DEFINE_STATIC_KEY_FALSE(sk_dynamic_might_resched);
+int __sched dynamic_might_resched(void)
+{
+	if (!static_branch_unlikely(&sk_dynamic_might_resched))
+		return 0;
+	return __cond_resched();
+}
+EXPORT_SYMBOL(dynamic_might_resched);
+#endif
+#endif
+
+/*
+ * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
+ * call schedule, and on return reacquire the lock.
+ *
+ * This works OK both with and without CONFIG_PREEMPTION. We do strange low-level
+ * operations here to prevent schedule() from being called twice (once via
+ * spin_unlock(), once by hand).
+ */
+int __cond_resched_lock(spinlock_t *lock)
+{
+	int resched = should_resched(PREEMPT_LOCK_OFFSET);
+	int ret = 0;
+
+	lockdep_assert_held(lock);
+
+	if (spin_needbreak(lock) || resched) {
+		spin_unlock(lock);
+		if (!_cond_resched())
+			cpu_relax();
+		ret = 1;
+		spin_lock(lock);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(__cond_resched_lock);
+
+int __cond_resched_rwlock_read(rwlock_t *lock)
+{
+	int resched = should_resched(PREEMPT_LOCK_OFFSET);
+	int ret = 0;
+
+	lockdep_assert_held_read(lock);
+
+	if (rwlock_needbreak(lock) || resched) {
+		read_unlock(lock);
+		if (!_cond_resched())
+			cpu_relax();
+		ret = 1;
+		read_lock(lock);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(__cond_resched_rwlock_read);
+
+int __cond_resched_rwlock_write(rwlock_t *lock)
+{
+	int resched = should_resched(PREEMPT_LOCK_OFFSET);
+	int ret = 0;
+
+	lockdep_assert_held_write(lock);
+
+	if (rwlock_needbreak(lock) || resched) {
+		write_unlock(lock);
+		if (!_cond_resched())
+			cpu_relax();
+		ret = 1;
+		write_lock(lock);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(__cond_resched_rwlock_write);
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+
+#ifdef CONFIG_GENERIC_ENTRY
+#include <linux/entry-common.h>
+#endif
+
+/*
+ * SC:cond_resched
+ * SC:might_resched
+ * SC:preempt_schedule
+ * SC:preempt_schedule_notrace
+ * SC:irqentry_exit_cond_resched
+ *
+ *
+ * NONE:
+ *   cond_resched               <- __cond_resched
+ *   might_resched              <- RET0
+ *   preempt_schedule           <- NOP
+ *   preempt_schedule_notrace   <- NOP
+ *   irqentry_exit_cond_resched <- NOP
+ *
+ * VOLUNTARY:
+ *   cond_resched               <- __cond_resched
+ *   might_resched              <- __cond_resched
+ *   preempt_schedule           <- NOP
+ *   preempt_schedule_notrace   <- NOP
+ *   irqentry_exit_cond_resched <- NOP
+ *
+ * FULL:
+ *   cond_resched               <- RET0
+ *   might_resched              <- RET0
+ *   preempt_schedule           <- preempt_schedule
+ *   preempt_schedule_notrace   <- preempt_schedule_notrace
+ *   irqentry_exit_cond_resched <- irqentry_exit_cond_resched
+ */
+
+enum {
+	preempt_dynamic_undefined = -1,
+	preempt_dynamic_none,
+	preempt_dynamic_voluntary,
+	preempt_dynamic_full,
+};
+
+int preempt_dynamic_mode = preempt_dynamic_undefined;
+
+int sched_dynamic_mode(const char *str)
+{
+	if (!strcmp(str, "none"))
+		return preempt_dynamic_none;
+
+	if (!strcmp(str, "voluntary"))
+		return preempt_dynamic_voluntary;
+
+	if (!strcmp(str, "full"))
+		return preempt_dynamic_full;
+
+	return -EINVAL;
+}
+
+#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
+#define preempt_dynamic_enable(f)	static_call_update(f, f##_dynamic_enabled)
+#define preempt_dynamic_disable(f)	static_call_update(f, f##_dynamic_disabled)
+#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
+#define preempt_dynamic_enable(f)	static_key_enable(&sk_dynamic_##f.key)
+#define preempt_dynamic_disable(f)	static_key_disable(&sk_dynamic_##f.key)
+#else
+#error "Unsupported PREEMPT_DYNAMIC mechanism"
+#endif
+
+void sched_dynamic_update(int mode)
+{
+	/*
+	 * Avoid {NONE,VOLUNTARY} -> FULL transitions from ever ending up in
+	 * the ZERO state, which is invalid.
+	 */
+	preempt_dynamic_enable(cond_resched);
+	preempt_dynamic_enable(might_resched);
+	preempt_dynamic_enable(preempt_schedule);
+	preempt_dynamic_enable(preempt_schedule_notrace);
+	preempt_dynamic_enable(irqentry_exit_cond_resched);
+
+	switch (mode) {
+	case preempt_dynamic_none:
+		preempt_dynamic_enable(cond_resched);
+		preempt_dynamic_disable(might_resched);
+		preempt_dynamic_disable(preempt_schedule);
+		preempt_dynamic_disable(preempt_schedule_notrace);
+		preempt_dynamic_disable(irqentry_exit_cond_resched);
+		pr_info("Dynamic Preempt: none\n");
+		break;
+
+	case preempt_dynamic_voluntary:
+		preempt_dynamic_enable(cond_resched);
+		preempt_dynamic_enable(might_resched);
+		preempt_dynamic_disable(preempt_schedule);
+		preempt_dynamic_disable(preempt_schedule_notrace);
+		preempt_dynamic_disable(irqentry_exit_cond_resched);
+		pr_info("Dynamic Preempt: voluntary\n");
+		break;
+
+	case preempt_dynamic_full:
+		preempt_dynamic_disable(cond_resched);
+		preempt_dynamic_disable(might_resched);
+		preempt_dynamic_enable(preempt_schedule);
+		preempt_dynamic_enable(preempt_schedule_notrace);
+		preempt_dynamic_enable(irqentry_exit_cond_resched);
+		pr_info("Dynamic Preempt: full\n");
+		break;
+	}
+
+	preempt_dynamic_mode = mode;
+}
+
+static int __init setup_preempt_mode(char *str)
+{
+	int mode = sched_dynamic_mode(str);
+	if (mode < 0) {
+		pr_warn("Dynamic Preempt: unsupported mode: %s\n", str);
+		return 0;
+	}
+
+	sched_dynamic_update(mode);
+	return 1;
+}
+__setup("preempt=", setup_preempt_mode);
+
+static void __init preempt_dynamic_init(void)
+{
+	if (preempt_dynamic_mode == preempt_dynamic_undefined) {
+		if (IS_ENABLED(CONFIG_PREEMPT_NONE)) {
+			sched_dynamic_update(preempt_dynamic_none);
+		} else if (IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY)) {
+			sched_dynamic_update(preempt_dynamic_voluntary);
+		} else {
+			/* Default static call setting, nothing to do */
+			WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT));
+			preempt_dynamic_mode = preempt_dynamic_full;
+			pr_info("Dynamic Preempt: full\n");
+		}
+	}
+}
+
+#define PREEMPT_MODEL_ACCESSOR(mode) \
+	bool preempt_model_##mode(void)						 \
+	{									 \
+		WARN_ON_ONCE(preempt_dynamic_mode == preempt_dynamic_undefined); \
+		return preempt_dynamic_mode == preempt_dynamic_##mode;		 \
+	}									 \
+	EXPORT_SYMBOL_GPL(preempt_model_##mode)
+
+PREEMPT_MODEL_ACCESSOR(none);
+PREEMPT_MODEL_ACCESSOR(voluntary);
+PREEMPT_MODEL_ACCESSOR(full);
+
+#else /* !CONFIG_PREEMPT_DYNAMIC */
+
+static inline void preempt_dynamic_init(void) { }
+
+#endif /* #ifdef CONFIG_PREEMPT_DYNAMIC */
+
+/**
+ * yield - yield the current processor to other threads.
+ *
+ * Do not ever use this function, there's a 99% chance you're doing it wrong.
+ *
+ * The scheduler is at all times free to pick the calling task as the most
+ * eligible task to run, if removing the yield() call from your code breaks
+ * it, it's already broken.
+ *
+ * Typical broken usage is:
+ *
+ * while (!event)
+ *	yield();
+ *
+ * where one assumes that yield() will let 'the other' process run that will
+ * make event true. If the current task is a SCHED_FIFO task that will never
+ * happen. Never use yield() as a progress guarantee!!
+ *
+ * If you want to use yield() to wait for something, use wait_event().
+ * If you want to use yield() to be 'nice' for others, use cond_resched().
+ * If you still want to use yield(), do not!
+ */
+void __sched yield(void)
+{
+	set_current_state(TASK_RUNNING);
+	do_sched_yield();
+}
+EXPORT_SYMBOL(yield);
+
+/**
+ * yield_to - yield the current processor to another thread in
+ * your thread group, or accelerate that thread toward the
+ * processor it's on.
+ * @p: target task
+ * @preempt: whether task preemption is allowed or not
+ *
+ * It's the caller's job to ensure that the target task struct
+ * can't go away on us before we can do any checks.
+ *
+ * Return:
+ *	true (>0) if we indeed boosted the target task.
+ *	false (0) if we failed to boost the target.
+ *	-ESRCH if there's no task to yield to.
+ */
+int __sched yield_to(struct task_struct *p, bool preempt)
+{
+	struct task_struct *curr = current;
+	struct rq *rq, *p_rq;
+	unsigned long flags;
+	int yielded = 0;
+
+	local_irq_save(flags);
+	rq = this_rq();
+
+again:
+	p_rq = task_rq(p);
+	/*
+	 * If we're the only runnable task on the rq and target rq also
+	 * has only one task, there's absolutely no point in yielding.
+	 */
+	if (rq->nr_running == 1 && p_rq->nr_running == 1) {
+		yielded = -ESRCH;
+		goto out_irq;
+	}
+
+	double_rq_lock(rq, p_rq);
+	if (task_rq(p) != p_rq) {
+		double_rq_unlock(rq, p_rq);
+		goto again;
+	}
+
+	if (!curr->sched_class->yield_to_task)
+		goto out_unlock;
+
+	if (curr->sched_class != p->sched_class)
+		goto out_unlock;
+
+	if (task_on_cpu(p_rq, p) || !task_is_running(p))
+		goto out_unlock;
+
+	yielded = curr->sched_class->yield_to_task(rq, p);
+	if (yielded) {
+		schedstat_inc(rq->yld_count);
+		/*
+		 * Make p's CPU reschedule; pick_next_entity takes care of
+		 * fairness.
+		 */
+		if (preempt && rq != p_rq)
+			resched_curr(p_rq);
+	}
+
+out_unlock:
+	double_rq_unlock(rq, p_rq);
+out_irq:
+	local_irq_restore(flags);
+
+	if (yielded > 0)
+		schedule();
+
+	return yielded;
+}
+EXPORT_SYMBOL_GPL(yield_to);
+
+int io_schedule_prepare(void)
+{
+	int old_iowait = current->in_iowait;
+
+	current->in_iowait = 1;
+	blk_flush_plug(current->plug, true);
+	return old_iowait;
+}
+
+void io_schedule_finish(int token)
+{
+	current->in_iowait = token;
+}
+
+/*
+ * This task is about to go to sleep on IO. Increment rq->nr_iowait so
+ * that process accounting knows that this is a task in IO wait state.
+ */
+long __sched io_schedule_timeout(long timeout)
+{
+	int token;
+	long ret;
+
+	token = io_schedule_prepare();
+	ret = schedule_timeout(timeout);
+	io_schedule_finish(token);
+
+	return ret;
+}
+EXPORT_SYMBOL(io_schedule_timeout);
+
+void __sched io_schedule(void)
+{
+	int token;
+
+	token = io_schedule_prepare();
+	schedule();
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL(io_schedule);
+
+/**
+ * sys_sched_get_priority_max - return maximum RT priority.
+ * @policy: scheduling class.
+ *
+ * Return: On success, this syscall returns the maximum
+ * rt_priority that can be used by a given scheduling class.
+ * On failure, a negative error code is returned.
+ */
+SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
+{
+	int ret = -EINVAL;
+
+	switch (policy) {
+	case SCHED_FIFO:
+	case SCHED_RR:
+		ret = MAX_RT_PRIO-1;
+		break;
+	case SCHED_DEADLINE:
+	case SCHED_NORMAL:
+	case SCHED_BATCH:
+	case SCHED_IDLE:
+		ret = 0;
+		break;
+	}
+	return ret;
+}
+
+/**
+ * sys_sched_get_priority_min - return minimum RT priority.
+ * @policy: scheduling class.
+ *
+ * Return: On success, this syscall returns the minimum
+ * rt_priority that can be used by a given scheduling class.
+ * On failure, a negative error code is returned.
+ */
+SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
+{
+	int ret = -EINVAL;
+
+	switch (policy) {
+	case SCHED_FIFO:
+	case SCHED_RR:
+		ret = 1;
+		break;
+	case SCHED_DEADLINE:
+	case SCHED_NORMAL:
+	case SCHED_BATCH:
+	case SCHED_IDLE:
+		ret = 0;
+	}
+	return ret;
+}
+
+static int sched_rr_get_interval(pid_t pid, struct timespec64 *t)
+{
+	struct task_struct *p;
+	unsigned int time_slice;
+	struct rq_flags rf;
+	struct rq *rq;
+	int retval;
+
+	if (pid < 0)
+		return -EINVAL;
+
+	retval = -ESRCH;
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	rq = task_rq_lock(p, &rf);
+	time_slice = 0;
+	if (p->sched_class->get_rr_interval)
+		time_slice = p->sched_class->get_rr_interval(rq, p);
+	task_rq_unlock(rq, p, &rf);
+
+	rcu_read_unlock();
+	jiffies_to_timespec64(time_slice, t);
+	return 0;
+
+out_unlock:
+	rcu_read_unlock();
+	return retval;
+}
+
+/**
+ * sys_sched_rr_get_interval - return the default timeslice of a process.
+ * @pid: pid of the process.
+ * @interval: userspace pointer to the timeslice value.
+ *
+ * this syscall writes the default timeslice value of a given process
+ * into the user-space timespec buffer. A value of '0' means infinity.
+ *
+ * Return: On success, 0 and the timeslice is in @interval. Otherwise,
+ * an error code.
+ */
+SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
+		struct __kernel_timespec __user *, interval)
+{
+	struct timespec64 t;
+	int retval = sched_rr_get_interval(pid, &t);
+
+	if (retval == 0)
+		retval = put_timespec64(&t, interval);
+
+	return retval;
+}
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+SYSCALL_DEFINE2(sched_rr_get_interval_time32, pid_t, pid,
+		struct old_timespec32 __user *, interval)
+{
+	struct timespec64 t;
+	int retval = sched_rr_get_interval(pid, &t);
+
+	if (retval == 0)
+		retval = put_old_timespec32(&t, interval);
+	return retval;
+}
+#endif
+
+void sched_show_task(struct task_struct *p)
+{
+	unsigned long free = 0;
+	int ppid;
+
+	if (!try_get_task_stack(p))
+		return;
+
+	pr_info("task:%-15.15s state:%c", p->comm, task_state_to_char(p));
+
+	if (task_is_running(p))
+		pr_cont("  running task    ");
+#ifdef CONFIG_DEBUG_STACK_USAGE
+	free = stack_not_used(p);
+#endif
+	ppid = 0;
+	rcu_read_lock();
+	if (pid_alive(p))
+		ppid = task_pid_nr(rcu_dereference(p->real_parent));
+	rcu_read_unlock();
+	pr_cont(" stack:%-5lu pid:%-5d ppid:%-6d flags:0x%08lx\n",
+		free, task_pid_nr(p), ppid,
+		read_task_thread_flags(p));
+
+	print_worker_info(KERN_INFO, p);
+	print_stop_info(KERN_INFO, p);
+	show_stack(p, NULL, KERN_INFO);
+	put_task_stack(p);
+}
+EXPORT_SYMBOL_GPL(sched_show_task);
+
+static inline bool
+state_filter_match(unsigned long state_filter, struct task_struct *p)
+{
+	unsigned int state = READ_ONCE(p->__state);
+
+	/* no filter, everything matches */
+	if (!state_filter)
+		return true;
+
+	/* filter, but doesn't match */
+	if (!(state & state_filter))
+		return false;
+
+	/*
+	 * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows
+	 * TASK_KILLABLE).
+	 */
+	if (state_filter == TASK_UNINTERRUPTIBLE && (state & TASK_NOLOAD))
+		return false;
+
+	return true;
+}
+
+
+void show_state_filter(unsigned int state_filter)
+{
+	struct task_struct *g, *p;
+
+	rcu_read_lock();
+	for_each_process_thread(g, p) {
+		/*
+		 * reset the NMI-timeout, listing all files on a slow
+		 * console might take a lot of time:
+		 * Also, reset softlockup watchdogs on all CPUs, because
+		 * another CPU might be blocked waiting for us to process
+		 * an IPI.
+		 */
+		touch_nmi_watchdog();
+		touch_all_softlockup_watchdogs();
+		if (state_filter_match(state_filter, p))
+			sched_show_task(p);
+	}
+
+#ifdef CONFIG_SCHED_DEBUG
+	if (!state_filter)
+		sysrq_sched_debug_show();
+#endif
+	rcu_read_unlock();
+	/*
+	 * Only show locks if all tasks are dumped:
+	 */
+	if (!state_filter)
+		debug_show_all_locks();
+}
+
+/**
+ * init_idle - set up an idle thread for a given CPU
+ * @idle: task in question
+ * @cpu: CPU the idle task belongs to
+ *
+ * NOTE: this function does not set the idle thread's NEED_RESCHED
+ * flag, to make booting more robust.
+ */
+void __init init_idle(struct task_struct *idle, int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+	__sched_fork(0, idle);
+
+	raw_spin_lock_irqsave(&idle->pi_lock, flags);
+	raw_spin_rq_lock(rq);
+
+	idle->__state = TASK_RUNNING;
+	idle->se.exec_start = sched_clock();
+	/*
+	 * PF_KTHREAD should already be set at this point; regardless, make it
+	 * look like a proper per-CPU kthread.
+	 */
+	idle->flags |= PF_KTHREAD | PF_NO_SETAFFINITY;
+	kthread_set_per_cpu(idle, cpu);
+
+#ifdef CONFIG_SMP
+	/*
+	 * It's possible that init_idle() gets called multiple times on a task,
+	 * in that case do_set_cpus_allowed() will not do the right thing.
+	 *
+	 * And since this is boot we can forgo the serialization.
+	 */
+	set_cpus_allowed_common(idle, cpumask_of(cpu), 0);
+#endif
+	/*
+	 * We're having a chicken and egg problem, even though we are
+	 * holding rq->lock, the CPU isn't yet set to this CPU so the
+	 * lockdep check in task_group() will fail.
+	 *
+	 * Similar case to sched_fork(). / Alternatively we could
+	 * use task_rq_lock() here and obtain the other rq->lock.
+	 *
+	 * Silence PROVE_RCU
+	 */
+	rcu_read_lock();
+	__set_task_cpu(idle, cpu);
+	rcu_read_unlock();
+
+	rq->idle = idle;
+	rcu_assign_pointer(rq->curr, idle);
+	idle->on_rq = TASK_ON_RQ_QUEUED;
+#ifdef CONFIG_SMP
+	idle->on_cpu = 1;
+#endif
+	raw_spin_rq_unlock(rq);
+	raw_spin_unlock_irqrestore(&idle->pi_lock, flags);
+
+	/* Set the preempt count _outside_ the spinlocks! */
+	init_idle_preempt_count(idle, cpu);
+
+	/*
+	 * The idle tasks have their own, simple scheduling class:
+	 */
+	idle->sched_class = &idle_sched_class;
+	ftrace_graph_init_idle_task(idle, cpu);
+	vtime_init_idle(idle, cpu);
+#ifdef CONFIG_SMP
+	sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
+#endif
+}
+
+#ifdef CONFIG_SMP
+
+int cpuset_cpumask_can_shrink(const struct cpumask *cur,
+			      const struct cpumask *trial)
+{
+	int ret = 1;
+
+	if (cpumask_empty(cur))
+		return ret;
+
+	ret = dl_cpuset_cpumask_can_shrink(cur, trial);
+
+	return ret;
+}
+
+int task_can_attach(struct task_struct *p)
+{
+	int ret = 0;
+
+	/*
+	 * Kthreads which disallow setaffinity shouldn't be moved
+	 * to a new cpuset; we don't want to change their CPU
+	 * affinity and isolating such threads by their set of
+	 * allowed nodes is unnecessary.  Thus, cpusets are not
+	 * applicable for such threads.  This prevents checking for
+	 * success of set_cpus_allowed_ptr() on all attached tasks
+	 * before cpus_mask may be changed.
+	 */
+	if (p->flags & PF_NO_SETAFFINITY)
+		ret = -EINVAL;
+
+	return ret;
+}
+
+bool sched_smp_initialized __read_mostly;
+
+#ifdef CONFIG_NUMA_BALANCING
+/* Migrate current task p to target_cpu */
+int migrate_task_to(struct task_struct *p, int target_cpu)
+{
+	struct migration_arg arg = { p, target_cpu };
+	int curr_cpu = task_cpu(p);
+
+	if (curr_cpu == target_cpu)
+		return 0;
+
+	if (!cpumask_test_cpu(target_cpu, p->cpus_ptr))
+		return -EINVAL;
+
+	/* TODO: This is not properly updating schedstats */
+
+	trace_sched_move_numa(p, curr_cpu, target_cpu);
+	return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg);
+}
+
+/*
+ * Requeue a task on a given node and accurately track the number of NUMA
+ * tasks on the runqueues
+ */
+void sched_setnuma(struct task_struct *p, int nid)
+{
+	bool queued, running;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(p, &rf);
+	queued = task_on_rq_queued(p);
+	running = task_current(rq, p);
+
+	if (queued)
+		dequeue_task(rq, p, DEQUEUE_SAVE);
+	if (running)
+		put_prev_task(rq, p);
+
+	p->numa_preferred_nid = nid;
+
+	if (queued)
+		enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
+	if (running)
+		set_next_task(rq, p);
+	task_rq_unlock(rq, p, &rf);
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * Ensure that the idle task is using init_mm right before its CPU goes
+ * offline.
+ */
+void idle_task_exit(void)
+{
+	struct mm_struct *mm = current->active_mm;
+
+	BUG_ON(cpu_online(smp_processor_id()));
+	BUG_ON(current != this_rq()->idle);
+
+	if (mm != &init_mm) {
+		switch_mm(mm, &init_mm, current);
+		finish_arch_post_lock_switch();
+	}
+
+	/* finish_cpu(), as ran on the BP, will clean up the active_mm state */
+}
+
+static int __balance_push_cpu_stop(void *arg)
+{
+	struct task_struct *p = arg;
+	struct rq *rq = this_rq();
+	struct rq_flags rf;
+	int cpu;
+
+	raw_spin_lock_irq(&p->pi_lock);
+	rq_lock(rq, &rf);
+
+	update_rq_clock(rq);
+
+	if (task_rq(p) == rq && task_on_rq_queued(p)) {
+		cpu = select_fallback_rq(rq->cpu, p);
+		rq = __migrate_task(rq, &rf, p, cpu);
+	}
+
+	rq_unlock(rq, &rf);
+	raw_spin_unlock_irq(&p->pi_lock);
+
+	put_task_struct(p);
+
+	return 0;
+}
+
+static DEFINE_PER_CPU(struct cpu_stop_work, push_work);
+
+/*
+ * Ensure we only run per-cpu kthreads once the CPU goes !active.
+ *
+ * This is enabled below SCHED_AP_ACTIVE; when !cpu_active(), but only
+ * effective when the hotplug motion is down.
+ */
+static void balance_push(struct rq *rq)
+{
+	struct task_struct *push_task = rq->curr;
+
+	lockdep_assert_rq_held(rq);
+
+	/*
+	 * Ensure the thing is persistent until balance_push_set(.on = false);
+	 */
+	rq->balance_callback = &balance_push_callback;
+
+	/*
+	 * Only active while going offline and when invoked on the outgoing
+	 * CPU.
+	 */
+	if (!cpu_dying(rq->cpu) || rq != this_rq())
+		return;
+
+	/*
+	 * Both the cpu-hotplug and stop task are in this case and are
+	 * required to complete the hotplug process.
+	 */
+	if (kthread_is_per_cpu(push_task) ||
+	    is_migration_disabled(push_task)) {
+
+		/*
+		 * If this is the idle task on the outgoing CPU try to wake
+		 * up the hotplug control thread which might wait for the
+		 * last task to vanish. The rcuwait_active() check is
+		 * accurate here because the waiter is pinned on this CPU
+		 * and can't obviously be running in parallel.
+		 *
+		 * On RT kernels this also has to check whether there are
+		 * pinned and scheduled out tasks on the runqueue. They
+		 * need to leave the migrate disabled section first.
+		 */
+		if (!rq->nr_running && !rq_has_pinned_tasks(rq) &&
+		    rcuwait_active(&rq->hotplug_wait)) {
+			raw_spin_rq_unlock(rq);
+			rcuwait_wake_up(&rq->hotplug_wait);
+			raw_spin_rq_lock(rq);
+		}
+		return;
+	}
+
+	get_task_struct(push_task);
+	/*
+	 * Temporarily drop rq->lock such that we can wake-up the stop task.
+	 * Both preemption and IRQs are still disabled.
+	 */
+	preempt_disable();
+	raw_spin_rq_unlock(rq);
+	stop_one_cpu_nowait(rq->cpu, __balance_push_cpu_stop, push_task,
+			    this_cpu_ptr(&push_work));
+	preempt_enable();
+	/*
+	 * At this point need_resched() is true and we'll take the loop in
+	 * schedule(). The next pick is obviously going to be the stop task
+	 * which kthread_is_per_cpu() and will push this task away.
+	 */
+	raw_spin_rq_lock(rq);
+}
+
+static void balance_push_set(int cpu, bool on)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+
+	rq_lock_irqsave(rq, &rf);
+	if (on) {
+		WARN_ON_ONCE(rq->balance_callback);
+		rq->balance_callback = &balance_push_callback;
+	} else if (rq->balance_callback == &balance_push_callback) {
+		rq->balance_callback = NULL;
+	}
+	rq_unlock_irqrestore(rq, &rf);
+}
+
+/*
+ * Invoked from a CPUs hotplug control thread after the CPU has been marked
+ * inactive. All tasks which are not per CPU kernel threads are either
+ * pushed off this CPU now via balance_push() or placed on a different CPU
+ * during wakeup. Wait until the CPU is quiescent.
+ */
+static void balance_hotplug_wait(void)
+{
+	struct rq *rq = this_rq();
+
+	rcuwait_wait_event(&rq->hotplug_wait,
+			   rq->nr_running == 1 && !rq_has_pinned_tasks(rq),
+			   TASK_UNINTERRUPTIBLE);
+}
+
+#else
+
+static inline void balance_push(struct rq *rq)
+{
+}
+
+static inline void balance_push_set(int cpu, bool on)
+{
+}
+
+static inline void balance_hotplug_wait(void)
+{
+}
+
+#endif /* CONFIG_HOTPLUG_CPU */
+
+void set_rq_online(struct rq *rq)
+{
+	if (!rq->online) {
+		const struct sched_class *class;
+
+		cpumask_set_cpu(rq->cpu, rq->rd->online);
+		rq->online = 1;
+
+		for_each_class(class) {
+			if (class->rq_online)
+				class->rq_online(rq);
+		}
+	}
+}
+
+void set_rq_offline(struct rq *rq)
+{
+	if (rq->online) {
+		const struct sched_class *class;
+
+		for_each_class(class) {
+			if (class->rq_offline)
+				class->rq_offline(rq);
+		}
+
+		cpumask_clear_cpu(rq->cpu, rq->rd->online);
+		rq->online = 0;
+	}
+}
+
+/*
+ * used to mark begin/end of suspend/resume:
+ */
+static int num_cpus_frozen;
+
+/*
+ * Update cpusets according to cpu_active mask.  If cpusets are
+ * disabled, cpuset_update_active_cpus() becomes a simple wrapper
+ * around partition_sched_domains().
+ *
+ * If we come here as part of a suspend/resume, don't touch cpusets because we
+ * want to restore it back to its original state upon resume anyway.
+ */
+static void cpuset_cpu_active(void)
+{
+	if (cpuhp_tasks_frozen) {
+		/*
+		 * num_cpus_frozen tracks how many CPUs are involved in suspend
+		 * resume sequence. As long as this is not the last online
+		 * operation in the resume sequence, just build a single sched
+		 * domain, ignoring cpusets.
+		 */
+		partition_sched_domains(1, NULL, NULL);
+		if (--num_cpus_frozen)
+			return;
+		/*
+		 * This is the last CPU online operation. So fall through and
+		 * restore the original sched domains by considering the
+		 * cpuset configurations.
+		 */
+		cpuset_force_rebuild();
+	}
+	cpuset_update_active_cpus();
+}
+
+static int cpuset_cpu_inactive(unsigned int cpu)
+{
+	if (!cpuhp_tasks_frozen) {
+		int ret = dl_bw_check_overflow(cpu);
+
+		if (ret)
+			return ret;
+		cpuset_update_active_cpus();
+	} else {
+		num_cpus_frozen++;
+		partition_sched_domains(1, NULL, NULL);
+	}
+	return 0;
+}
+
+int sched_cpu_activate(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+
+	/*
+	 * Clear the balance_push callback and prepare to schedule
+	 * regular tasks.
+	 */
+	balance_push_set(cpu, false);
+
+#ifdef CONFIG_SCHED_SMT
+	/*
+	 * When going up, increment the number of cores with SMT present.
+	 */
+	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
+		static_branch_inc_cpuslocked(&sched_smt_present);
+#endif
+	set_cpu_active(cpu, true);
+
+	if (sched_smp_initialized) {
+		sched_update_numa(cpu, true);
+		sched_domains_numa_masks_set(cpu);
+		cpuset_cpu_active();
+	}
+
+	/*
+	 * Put the rq online, if not already. This happens:
+	 *
+	 * 1) In the early boot process, because we build the real domains
+	 *    after all CPUs have been brought up.
+	 *
+	 * 2) At runtime, if cpuset_cpu_active() fails to rebuild the
+	 *    domains.
+	 */
+	rq_lock_irqsave(rq, &rf);
+	if (rq->rd) {
+		BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
+		set_rq_online(rq);
+	}
+	rq_unlock_irqrestore(rq, &rf);
+
+	return 0;
+}
+
+int sched_cpu_deactivate(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+	int ret;
+
+	/*
+	 * Remove CPU from nohz.idle_cpus_mask to prevent participating in
+	 * load balancing when not active
+	 */
+	nohz_balance_exit_idle(rq);
+
+	set_cpu_active(cpu, false);
+
+	/*
+	 * From this point forward, this CPU will refuse to run any task that
+	 * is not: migrate_disable() or KTHREAD_IS_PER_CPU, and will actively
+	 * push those tasks away until this gets cleared, see
+	 * sched_cpu_dying().
+	 */
+	balance_push_set(cpu, true);
+
+	/*
+	 * We've cleared cpu_active_mask / set balance_push, wait for all
+	 * preempt-disabled and RCU users of this state to go away such that
+	 * all new such users will observe it.
+	 *
+	 * Specifically, we rely on ttwu to no longer target this CPU, see
+	 * ttwu_queue_cond() and is_cpu_allowed().
+	 *
+	 * Do sync before park smpboot threads to take care the rcu boost case.
+	 */
+	synchronize_rcu();
+
+	rq_lock_irqsave(rq, &rf);
+	if (rq->rd) {
+		update_rq_clock(rq);
+		BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
+		set_rq_offline(rq);
+	}
+	rq_unlock_irqrestore(rq, &rf);
+
+#ifdef CONFIG_SCHED_SMT
+	/*
+	 * When going down, decrement the number of cores with SMT present.
+	 */
+	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
+		static_branch_dec_cpuslocked(&sched_smt_present);
+
+	sched_core_cpu_deactivate(cpu);
+#endif
+
+	if (!sched_smp_initialized)
+		return 0;
+
+	sched_update_numa(cpu, false);
+	ret = cpuset_cpu_inactive(cpu);
+	if (ret) {
+		balance_push_set(cpu, false);
+		set_cpu_active(cpu, true);
+		sched_update_numa(cpu, true);
+		return ret;
+	}
+	sched_domains_numa_masks_clear(cpu);
+	return 0;
+}
+
+static void sched_rq_cpu_starting(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	rq->calc_load_update = calc_load_update;
+	update_max_interval();
+}
+
+int sched_cpu_starting(unsigned int cpu)
+{
+	sched_core_cpu_starting(cpu);
+	sched_rq_cpu_starting(cpu);
+	sched_tick_start(cpu);
+	return 0;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+/*
+ * Invoked immediately before the stopper thread is invoked to bring the
+ * CPU down completely. At this point all per CPU kthreads except the
+ * hotplug thread (current) and the stopper thread (inactive) have been
+ * either parked or have been unbound from the outgoing CPU. Ensure that
+ * any of those which might be on the way out are gone.
+ *
+ * If after this point a bound task is being woken on this CPU then the
+ * responsible hotplug callback has failed to do it's job.
+ * sched_cpu_dying() will catch it with the appropriate fireworks.
+ */
+int sched_cpu_wait_empty(unsigned int cpu)
+{
+	balance_hotplug_wait();
+	return 0;
+}
+
+/*
+ * Since this CPU is going 'away' for a while, fold any nr_active delta we
+ * might have. Called from the CPU stopper task after ensuring that the
+ * stopper is the last running task on the CPU, so nr_active count is
+ * stable. We need to take the teardown thread which is calling this into
+ * account, so we hand in adjust = 1 to the load calculation.
+ *
+ * Also see the comment "Global load-average calculations".
+ */
+static void calc_load_migrate(struct rq *rq)
+{
+	long delta = calc_load_fold_active(rq, 1);
+
+	if (delta)
+		atomic_long_add(delta, &calc_load_tasks);
+}
+
+static void dump_rq_tasks(struct rq *rq, const char *loglvl)
+{
+	struct task_struct *g, *p;
+	int cpu = cpu_of(rq);
+
+	lockdep_assert_rq_held(rq);
+
+	printk("%sCPU%d enqueued tasks (%u total):\n", loglvl, cpu, rq->nr_running);
+	for_each_process_thread(g, p) {
+		if (task_cpu(p) != cpu)
+			continue;
+
+		if (!task_on_rq_queued(p))
+			continue;
+
+		printk("%s\tpid: %d, name: %s\n", loglvl, p->pid, p->comm);
+	}
+}
+
+int sched_cpu_dying(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+
+	/* Handle pending wakeups and then migrate everything off */
+	sched_tick_stop(cpu);
+
+	rq_lock_irqsave(rq, &rf);
+	if (rq->nr_running != 1 || rq_has_pinned_tasks(rq)) {
+		WARN(true, "Dying CPU not properly vacated!");
+		dump_rq_tasks(rq, KERN_WARNING);
+	}
+	rq_unlock_irqrestore(rq, &rf);
+
+	calc_load_migrate(rq);
+	update_max_interval();
+	hrtick_clear(rq);
+	sched_core_cpu_dying(cpu);
+	return 0;
+}
+#endif
+
+void __init sched_init_smp(void)
+{
+	sched_init_numa(NUMA_NO_NODE);
+
+	/*
+	 * There's no userspace yet to cause hotplug operations; hence all the
+	 * CPU masks are stable and all blatant races in the below code cannot
+	 * happen.
+	 */
+	mutex_lock(&sched_domains_mutex);
+	sched_init_domains(cpu_active_mask);
+	mutex_unlock(&sched_domains_mutex);
+
+	/* Move init over to a non-isolated CPU */
+	if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_TYPE_DOMAIN)) < 0)
+		BUG();
+	current->flags &= ~PF_NO_SETAFFINITY;
+	sched_init_granularity();
+
+	init_sched_rt_class();
+	init_sched_dl_class();
+
+	sched_smp_initialized = true;
+}
+
+static int __init migration_init(void)
+{
+	sched_cpu_starting(smp_processor_id());
+	return 0;
+}
+early_initcall(migration_init);
+
+#else
+void __init sched_init_smp(void)
+{
+	sched_init_granularity();
+}
+#endif /* CONFIG_SMP */
+
+int in_sched_functions(unsigned long addr)
+{
+	return in_lock_functions(addr) ||
+		(addr >= (unsigned long)__sched_text_start
+		&& addr < (unsigned long)__sched_text_end);
+}
+
+#ifdef CONFIG_CGROUP_SCHED
+/*
+ * Default task group.
+ * Every task in system belongs to this group at bootup.
+ */
+struct task_group root_task_group;
+LIST_HEAD(task_groups);
+
+/* Cacheline aligned slab cache for task_group */
+static struct kmem_cache *task_group_cache __read_mostly;
+#endif
+
+void __init sched_init(void)
+{
+	unsigned long ptr = 0;
+	int i;
+
+	/* Make sure the linker didn't screw up */
+	BUG_ON(&idle_sched_class != &fair_sched_class + 1 ||
+	       &fair_sched_class != &rt_sched_class + 1 ||
+	       &rt_sched_class   != &dl_sched_class + 1);
+#ifdef CONFIG_SMP
+	BUG_ON(&dl_sched_class != &stop_sched_class + 1);
+#endif
+
+	wait_bit_init();
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	ptr += 2 * nr_cpu_ids * sizeof(void **);
+#endif
+#ifdef CONFIG_RT_GROUP_SCHED
+	ptr += 2 * nr_cpu_ids * sizeof(void **);
+#endif
+	if (ptr) {
+		ptr = (unsigned long)kzalloc(ptr, GFP_NOWAIT);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+		root_task_group.se = (struct sched_entity **)ptr;
+		ptr += nr_cpu_ids * sizeof(void **);
+
+		root_task_group.cfs_rq = (struct cfs_rq **)ptr;
+		ptr += nr_cpu_ids * sizeof(void **);
+
+		root_task_group.shares = ROOT_TASK_GROUP_LOAD;
+		init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+#ifdef CONFIG_RT_GROUP_SCHED
+		root_task_group.rt_se = (struct sched_rt_entity **)ptr;
+		ptr += nr_cpu_ids * sizeof(void **);
+
+		root_task_group.rt_rq = (struct rt_rq **)ptr;
+		ptr += nr_cpu_ids * sizeof(void **);
+
+#endif /* CONFIG_RT_GROUP_SCHED */
+	}
+
+	init_rt_bandwidth(&def_rt_bandwidth, global_rt_period(), global_rt_runtime());
+
+#ifdef CONFIG_SMP
+	init_defrootdomain();
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	init_rt_bandwidth(&root_task_group.rt_bandwidth,
+			global_rt_period(), global_rt_runtime());
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_CGROUP_SCHED
+	task_group_cache = KMEM_CACHE(task_group, 0);
+
+	list_add(&root_task_group.list, &task_groups);
+	INIT_LIST_HEAD(&root_task_group.children);
+	INIT_LIST_HEAD(&root_task_group.siblings);
+	autogroup_init(&init_task);
+#endif /* CONFIG_CGROUP_SCHED */
+
+	for_each_possible_cpu(i) {
+		struct rq *rq;
+
+		rq = cpu_rq(i);
+		raw_spin_lock_init(&rq->__lock);
+		rq->nr_running = 0;
+		rq->calc_load_active = 0;
+		rq->calc_load_update = jiffies + LOAD_FREQ;
+		init_cfs_rq(&rq->cfs);
+		init_rt_rq(&rq->rt);
+		init_dl_rq(&rq->dl);
+#ifdef CONFIG_FAIR_GROUP_SCHED
+		INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
+		rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
+		/*
+		 * How much CPU bandwidth does root_task_group get?
+		 *
+		 * In case of task-groups formed thr' the cgroup filesystem, it
+		 * gets 100% of the CPU resources in the system. This overall
+		 * system CPU resource is divided among the tasks of
+		 * root_task_group and its child task-groups in a fair manner,
+		 * based on each entity's (task or task-group's) weight
+		 * (se->load.weight).
+		 *
+		 * In other words, if root_task_group has 10 tasks of weight
+		 * 1024) and two child groups A0 and A1 (of weight 1024 each),
+		 * then A0's share of the CPU resource is:
+		 *
+		 *	A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
+		 *
+		 * We achieve this by letting root_task_group's tasks sit
+		 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
+		 */
+		init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+		rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
+#ifdef CONFIG_RT_GROUP_SCHED
+		init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
+#endif
+#ifdef CONFIG_SMP
+		rq->sd = NULL;
+		rq->rd = NULL;
+		rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE;
+		rq->balance_callback = &balance_push_callback;
+		rq->active_balance = 0;
+		rq->next_balance = jiffies;
+		rq->push_cpu = 0;
+		rq->cpu = i;
+		rq->online = 0;
+		rq->idle_stamp = 0;
+		rq->avg_idle = 2*sysctl_sched_migration_cost;
+		rq->wake_stamp = jiffies;
+		rq->wake_avg_idle = rq->avg_idle;
+		rq->max_idle_balance_cost = sysctl_sched_migration_cost;
+
+		INIT_LIST_HEAD(&rq->cfs_tasks);
+
+		rq_attach_root(rq, &def_root_domain);
+#ifdef CONFIG_NO_HZ_COMMON
+		rq->last_blocked_load_update_tick = jiffies;
+		atomic_set(&rq->nohz_flags, 0);
+
+		INIT_CSD(&rq->nohz_csd, nohz_csd_func, rq);
+#endif
+#ifdef CONFIG_HOTPLUG_CPU
+		rcuwait_init(&rq->hotplug_wait);
+#endif
+#endif /* CONFIG_SMP */
+		hrtick_rq_init(rq);
+		atomic_set(&rq->nr_iowait, 0);
+
+#ifdef CONFIG_SCHED_CORE
+		rq->core = rq;
+		rq->core_pick = NULL;
+		rq->core_enabled = 0;
+		rq->core_tree = RB_ROOT;
+		rq->core_forceidle_count = 0;
+		rq->core_forceidle_occupation = 0;
+		rq->core_forceidle_start = 0;
+
+		rq->core_cookie = 0UL;
+#endif
+	}
+
+	set_load_weight(&init_task, false);
+
+	/*
+	 * The boot idle thread does lazy MMU switching as well:
+	 */
+	mmgrab(&init_mm);
+	enter_lazy_tlb(&init_mm, current);
+
+	/*
+	 * The idle task doesn't need the kthread struct to function, but it
+	 * is dressed up as a per-CPU kthread and thus needs to play the part
+	 * if we want to avoid special-casing it in code that deals with per-CPU
+	 * kthreads.
+	 */
+	WARN_ON(!set_kthread_struct(current));
+
+	/*
+	 * Make us the idle thread. Technically, schedule() should not be
+	 * called from this thread, however somewhere below it might be,
+	 * but because we are the idle thread, we just pick up running again
+	 * when this runqueue becomes "idle".
+	 */
+	init_idle(current, smp_processor_id());
+
+	calc_load_update = jiffies + LOAD_FREQ;
+
+#ifdef CONFIG_SMP
+	idle_thread_set_boot_cpu();
+	balance_push_set(smp_processor_id(), false);
+#endif
+	init_sched_fair_class();
+
+	psi_init();
+
+	init_uclamp();
+
+	preempt_dynamic_init();
+
+	scheduler_running = 1;
+}
+
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+
+void __might_sleep(const char *file, int line)
+{
+	unsigned int state = get_current_state();
+	/*
+	 * Blocking primitives will set (and therefore destroy) current->state,
+	 * since we will exit with TASK_RUNNING make sure we enter with it,
+	 * otherwise we will destroy state.
+	 */
+	WARN_ONCE(state != TASK_RUNNING && current->task_state_change,
+			"do not call blocking ops when !TASK_RUNNING; "
+			"state=%x set at [<%p>] %pS\n", state,
+			(void *)current->task_state_change,
+			(void *)current->task_state_change);
+
+	__might_resched(file, line, 0);
+}
+EXPORT_SYMBOL(__might_sleep);
+
+static void print_preempt_disable_ip(int preempt_offset, unsigned long ip)
+{
+	if (!IS_ENABLED(CONFIG_DEBUG_PREEMPT))
+		return;
+
+	if (preempt_count() == preempt_offset)
+		return;
+
+	pr_err("Preemption disabled at:");
+	print_ip_sym(KERN_ERR, ip);
+}
+
+static inline bool resched_offsets_ok(unsigned int offsets)
+{
+	unsigned int nested = preempt_count();
+
+	nested += rcu_preempt_depth() << MIGHT_RESCHED_RCU_SHIFT;
+
+	return nested == offsets;
+}
+
+void __might_resched(const char *file, int line, unsigned int offsets)
+{
+	/* Ratelimiting timestamp: */
+	static unsigned long prev_jiffy;
+
+	unsigned long preempt_disable_ip;
+
+	/* WARN_ON_ONCE() by default, no rate limit required: */
+	rcu_sleep_check();
+
+	if ((resched_offsets_ok(offsets) && !irqs_disabled() &&
+	     !is_idle_task(current) && !current->non_block_count) ||
+	    system_state == SYSTEM_BOOTING || system_state > SYSTEM_RUNNING ||
+	    oops_in_progress)
+		return;
+
+	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+		return;
+	prev_jiffy = jiffies;
+
+	/* Save this before calling printk(), since that will clobber it: */
+	preempt_disable_ip = get_preempt_disable_ip(current);
+
+	pr_err("BUG: sleeping function called from invalid context at %s:%d\n",
+	       file, line);
+	pr_err("in_atomic(): %d, irqs_disabled(): %d, non_block: %d, pid: %d, name: %s\n",
+	       in_atomic(), irqs_disabled(), current->non_block_count,
+	       current->pid, current->comm);
+	pr_err("preempt_count: %x, expected: %x\n", preempt_count(),
+	       offsets & MIGHT_RESCHED_PREEMPT_MASK);
+
+	if (IS_ENABLED(CONFIG_PREEMPT_RCU)) {
+		pr_err("RCU nest depth: %d, expected: %u\n",
+		       rcu_preempt_depth(), offsets >> MIGHT_RESCHED_RCU_SHIFT);
+	}
+
+	if (task_stack_end_corrupted(current))
+		pr_emerg("Thread overran stack, or stack corrupted\n");
+
+	debug_show_held_locks(current);
+	if (irqs_disabled())
+		print_irqtrace_events(current);
+
+	print_preempt_disable_ip(offsets & MIGHT_RESCHED_PREEMPT_MASK,
+				 preempt_disable_ip);
+
+	dump_stack();
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+EXPORT_SYMBOL(__might_resched);
+
+void __cant_sleep(const char *file, int line, int preempt_offset)
+{
+	static unsigned long prev_jiffy;
+
+	if (irqs_disabled())
+		return;
+
+	if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
+		return;
+
+	if (preempt_count() > preempt_offset)
+		return;
+
+	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+		return;
+	prev_jiffy = jiffies;
+
+	printk(KERN_ERR "BUG: assuming atomic context at %s:%d\n", file, line);
+	printk(KERN_ERR "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
+			in_atomic(), irqs_disabled(),
+			current->pid, current->comm);
+
+	debug_show_held_locks(current);
+	dump_stack();
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+EXPORT_SYMBOL_GPL(__cant_sleep);
+
+#ifdef CONFIG_SMP
+void __cant_migrate(const char *file, int line)
+{
+	static unsigned long prev_jiffy;
+
+	if (irqs_disabled())
+		return;
+
+	if (is_migration_disabled(current))
+		return;
+
+	if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
+		return;
+
+	if (preempt_count() > 0)
+		return;
+
+	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+		return;
+	prev_jiffy = jiffies;
+
+	pr_err("BUG: assuming non migratable context at %s:%d\n", file, line);
+	pr_err("in_atomic(): %d, irqs_disabled(): %d, migration_disabled() %u pid: %d, name: %s\n",
+	       in_atomic(), irqs_disabled(), is_migration_disabled(current),
+	       current->pid, current->comm);
+
+	debug_show_held_locks(current);
+	dump_stack();
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+EXPORT_SYMBOL_GPL(__cant_migrate);
+#endif
+#endif
+
+#ifdef CONFIG_MAGIC_SYSRQ
+void normalize_rt_tasks(void)
+{
+	struct task_struct *g, *p;
+	struct sched_attr attr = {
+		.sched_policy = SCHED_NORMAL,
+	};
+
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, p) {
+		/*
+		 * Only normalize user tasks:
+		 */
+		if (p->flags & PF_KTHREAD)
+			continue;
+
+		p->se.exec_start = 0;
+		schedstat_set(p->stats.wait_start,  0);
+		schedstat_set(p->stats.sleep_start, 0);
+		schedstat_set(p->stats.block_start, 0);
+
+		if (!dl_task(p) && !rt_task(p)) {
+			/*
+			 * Renice negative nice level userspace
+			 * tasks back to 0:
+			 */
+			if (task_nice(p) < 0)
+				set_user_nice(p, 0);
+			continue;
+		}
+
+		__sched_setscheduler(p, &attr, false, false);
+	}
+	read_unlock(&tasklist_lock);
+}
+
+#endif /* CONFIG_MAGIC_SYSRQ */
+
+#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
+/*
+ * These functions are only useful for the IA64 MCA handling, or kdb.
+ *
+ * They can only be called when the whole system has been
+ * stopped - every CPU needs to be quiescent, and no scheduling
+ * activity can take place. Using them for anything else would
+ * be a serious bug, and as a result, they aren't even visible
+ * under any other configuration.
+ */
+
+/**
+ * curr_task - return the current task for a given CPU.
+ * @cpu: the processor in question.
+ *
+ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
+ *
+ * Return: The current task for @cpu.
+ */
+struct task_struct *curr_task(int cpu)
+{
+	return cpu_curr(cpu);
+}
+
+#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
+
+#ifdef CONFIG_IA64
+/**
+ * ia64_set_curr_task - set the current task for a given CPU.
+ * @cpu: the processor in question.
+ * @p: the task pointer to set.
+ *
+ * Description: This function must only be used when non-maskable interrupts
+ * are serviced on a separate stack. It allows the architecture to switch the
+ * notion of the current task on a CPU in a non-blocking manner. This function
+ * must be called with all CPU's synchronized, and interrupts disabled, the
+ * and caller must save the original value of the current task (see
+ * curr_task() above) and restore that value before reenabling interrupts and
+ * re-starting the system.
+ *
+ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
+ */
+void ia64_set_curr_task(int cpu, struct task_struct *p)
+{
+	cpu_curr(cpu) = p;
+}
+
+#endif
+
+#ifdef CONFIG_CGROUP_SCHED
+/* task_group_lock serializes the addition/removal of task groups */
+static DEFINE_SPINLOCK(task_group_lock);
+
+static inline void alloc_uclamp_sched_group(struct task_group *tg,
+					    struct task_group *parent)
+{
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+	enum uclamp_id clamp_id;
+
+	for_each_clamp_id(clamp_id) {
+		uclamp_se_set(&tg->uclamp_req[clamp_id],
+			      uclamp_none(clamp_id), false);
+		tg->uclamp[clamp_id] = parent->uclamp[clamp_id];
+	}
+#endif
+}
+
+static void sched_free_group(struct task_group *tg)
+{
+	free_fair_sched_group(tg);
+	free_rt_sched_group(tg);
+	autogroup_free(tg);
+	kmem_cache_free(task_group_cache, tg);
+}
+
+static void sched_free_group_rcu(struct rcu_head *rcu)
+{
+	sched_free_group(container_of(rcu, struct task_group, rcu));
+}
+
+static void sched_unregister_group(struct task_group *tg)
+{
+	unregister_fair_sched_group(tg);
+	unregister_rt_sched_group(tg);
+	/*
+	 * We have to wait for yet another RCU grace period to expire, as
+	 * print_cfs_stats() might run concurrently.
+	 */
+	call_rcu(&tg->rcu, sched_free_group_rcu);
+}
+
+/* allocate runqueue etc for a new task group */
+struct task_group *sched_create_group(struct task_group *parent)
+{
+	struct task_group *tg;
+
+	tg = kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO);
+	if (!tg)
+		return ERR_PTR(-ENOMEM);
+
+	if (!alloc_fair_sched_group(tg, parent))
+		goto err;
+
+	if (!alloc_rt_sched_group(tg, parent))
+		goto err;
+
+	alloc_uclamp_sched_group(tg, parent);
+
+	return tg;
+
+err:
+	sched_free_group(tg);
+	return ERR_PTR(-ENOMEM);
+}
+
+void sched_online_group(struct task_group *tg, struct task_group *parent)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&task_group_lock, flags);
+	list_add_rcu(&tg->list, &task_groups);
+
+	/* Root should already exist: */
+	WARN_ON(!parent);
+
+	tg->parent = parent;
+	INIT_LIST_HEAD(&tg->children);
+	list_add_rcu(&tg->siblings, &parent->children);
+	spin_unlock_irqrestore(&task_group_lock, flags);
+
+	online_fair_sched_group(tg);
+}
+
+/* rcu callback to free various structures associated with a task group */
+static void sched_unregister_group_rcu(struct rcu_head *rhp)
+{
+	/* Now it should be safe to free those cfs_rqs: */
+	sched_unregister_group(container_of(rhp, struct task_group, rcu));
+}
+
+void sched_destroy_group(struct task_group *tg)
+{
+	/* Wait for possible concurrent references to cfs_rqs complete: */
+	call_rcu(&tg->rcu, sched_unregister_group_rcu);
+}
+
+void sched_release_group(struct task_group *tg)
+{
+	unsigned long flags;
+
+	/*
+	 * Unlink first, to avoid walk_tg_tree_from() from finding us (via
+	 * sched_cfs_period_timer()).
+	 *
+	 * For this to be effective, we have to wait for all pending users of
+	 * this task group to leave their RCU critical section to ensure no new
+	 * user will see our dying task group any more. Specifically ensure
+	 * that tg_unthrottle_up() won't add decayed cfs_rq's to it.
+	 *
+	 * We therefore defer calling unregister_fair_sched_group() to
+	 * sched_unregister_group() which is guarantied to get called only after the
+	 * current RCU grace period has expired.
+	 */
+	spin_lock_irqsave(&task_group_lock, flags);
+	list_del_rcu(&tg->list);
+	list_del_rcu(&tg->siblings);
+	spin_unlock_irqrestore(&task_group_lock, flags);
+}
+
+static void sched_change_group(struct task_struct *tsk)
+{
+	struct task_group *tg;
+
+	/*
+	 * All callers are synchronized by task_rq_lock(); we do not use RCU
+	 * which is pointless here. Thus, we pass "true" to task_css_check()
+	 * to prevent lockdep warnings.
+	 */
+	tg = container_of(task_css_check(tsk, cpu_cgrp_id, true),
+			  struct task_group, css);
+	tg = autogroup_task_group(tsk, tg);
+	tsk->sched_task_group = tg;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	if (tsk->sched_class->task_change_group)
+		tsk->sched_class->task_change_group(tsk);
+	else
+#endif
+		set_task_rq(tsk, task_cpu(tsk));
+}
+
+/*
+ * Change task's runqueue when it moves between groups.
+ *
+ * The caller of this function should have put the task in its new group by
+ * now. This function just updates tsk->se.cfs_rq and tsk->se.parent to reflect
+ * its new group.
+ */
+void sched_move_task(struct task_struct *tsk)
+{
+	int queued, running, queue_flags =
+		DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(tsk, &rf);
+	update_rq_clock(rq);
+
+	running = task_current(rq, tsk);
+	queued = task_on_rq_queued(tsk);
+
+	if (queued)
+		dequeue_task(rq, tsk, queue_flags);
+	if (running)
+		put_prev_task(rq, tsk);
+
+	sched_change_group(tsk);
+
+	if (queued)
+		enqueue_task(rq, tsk, queue_flags);
+	if (running) {
+		set_next_task(rq, tsk);
+		/*
+		 * After changing group, the running task may have joined a
+		 * throttled one but it's still the running task. Trigger a
+		 * resched to make sure that task can still run.
+		 */
+		resched_curr(rq);
+	}
+
+	task_rq_unlock(rq, tsk, &rf);
+}
+
+static inline struct task_group *css_tg(struct cgroup_subsys_state *css)
+{
+	return css ? container_of(css, struct task_group, css) : NULL;
+}
+
+static struct cgroup_subsys_state *
+cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+	struct task_group *parent = css_tg(parent_css);
+	struct task_group *tg;
+
+	if (!parent) {
+		/* This is early initialization for the top cgroup */
+		return &root_task_group.css;
+	}
+
+	tg = sched_create_group(parent);
+	if (IS_ERR(tg))
+		return ERR_PTR(-ENOMEM);
+
+	return &tg->css;
+}
+
+/* Expose task group only after completing cgroup initialization */
+static int cpu_cgroup_css_online(struct cgroup_subsys_state *css)
+{
+	struct task_group *tg = css_tg(css);
+	struct task_group *parent = css_tg(css->parent);
+
+	if (parent)
+		sched_online_group(tg, parent);
+
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+	/* Propagate the effective uclamp value for the new group */
+	mutex_lock(&uclamp_mutex);
+	rcu_read_lock();
+	cpu_util_update_eff(css);
+	rcu_read_unlock();
+	mutex_unlock(&uclamp_mutex);
+#endif
+
+	return 0;
+}
+
+static void cpu_cgroup_css_released(struct cgroup_subsys_state *css)
+{
+	struct task_group *tg = css_tg(css);
+
+	sched_release_group(tg);
+}
+
+static void cpu_cgroup_css_free(struct cgroup_subsys_state *css)
+{
+	struct task_group *tg = css_tg(css);
+
+	/*
+	 * Relies on the RCU grace period between css_released() and this.
+	 */
+	sched_unregister_group(tg);
+}
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static int cpu_cgroup_can_attach(struct cgroup_taskset *tset)
+{
+	struct task_struct *task;
+	struct cgroup_subsys_state *css;
+
+	cgroup_taskset_for_each(task, css, tset) {
+		if (!sched_rt_can_attach(css_tg(css), task))
+			return -EINVAL;
+	}
+	return 0;
+}
+#endif
+
+static void cpu_cgroup_attach(struct cgroup_taskset *tset)
+{
+	struct task_struct *task;
+	struct cgroup_subsys_state *css;
+
+	cgroup_taskset_for_each(task, css, tset)
+		sched_move_task(task);
+}
+
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+static void cpu_util_update_eff(struct cgroup_subsys_state *css)
+{
+	struct cgroup_subsys_state *top_css = css;
+	struct uclamp_se *uc_parent = NULL;
+	struct uclamp_se *uc_se = NULL;
+	unsigned int eff[UCLAMP_CNT];
+	enum uclamp_id clamp_id;
+	unsigned int clamps;
+
+	lockdep_assert_held(&uclamp_mutex);
+	SCHED_WARN_ON(!rcu_read_lock_held());
+
+	css_for_each_descendant_pre(css, top_css) {
+		uc_parent = css_tg(css)->parent
+			? css_tg(css)->parent->uclamp : NULL;
+
+		for_each_clamp_id(clamp_id) {
+			/* Assume effective clamps matches requested clamps */
+			eff[clamp_id] = css_tg(css)->uclamp_req[clamp_id].value;
+			/* Cap effective clamps with parent's effective clamps */
+			if (uc_parent &&
+			    eff[clamp_id] > uc_parent[clamp_id].value) {
+				eff[clamp_id] = uc_parent[clamp_id].value;
+			}
+		}
+		/* Ensure protection is always capped by limit */
+		eff[UCLAMP_MIN] = min(eff[UCLAMP_MIN], eff[UCLAMP_MAX]);
+
+		/* Propagate most restrictive effective clamps */
+		clamps = 0x0;
+		uc_se = css_tg(css)->uclamp;
+		for_each_clamp_id(clamp_id) {
+			if (eff[clamp_id] == uc_se[clamp_id].value)
+				continue;
+			uc_se[clamp_id].value = eff[clamp_id];
+			uc_se[clamp_id].bucket_id = uclamp_bucket_id(eff[clamp_id]);
+			clamps |= (0x1 << clamp_id);
+		}
+		if (!clamps) {
+			css = css_rightmost_descendant(css);
+			continue;
+		}
+
+		/* Immediately update descendants RUNNABLE tasks */
+		uclamp_update_active_tasks(css);
+	}
+}
+
+/*
+ * Integer 10^N with a given N exponent by casting to integer the literal "1eN"
+ * C expression. Since there is no way to convert a macro argument (N) into a
+ * character constant, use two levels of macros.
+ */
+#define _POW10(exp) ((unsigned int)1e##exp)
+#define POW10(exp) _POW10(exp)
+
+struct uclamp_request {
+#define UCLAMP_PERCENT_SHIFT	2
+#define UCLAMP_PERCENT_SCALE	(100 * POW10(UCLAMP_PERCENT_SHIFT))
+	s64 percent;
+	u64 util;
+	int ret;
+};
+
+static inline struct uclamp_request
+capacity_from_percent(char *buf)
+{
+	struct uclamp_request req = {
+		.percent = UCLAMP_PERCENT_SCALE,
+		.util = SCHED_CAPACITY_SCALE,
+		.ret = 0,
+	};
+
+	buf = strim(buf);
+	if (strcmp(buf, "max")) {
+		req.ret = cgroup_parse_float(buf, UCLAMP_PERCENT_SHIFT,
+					     &req.percent);
+		if (req.ret)
+			return req;
+		if ((u64)req.percent > UCLAMP_PERCENT_SCALE) {
+			req.ret = -ERANGE;
+			return req;
+		}
+
+		req.util = req.percent << SCHED_CAPACITY_SHIFT;
+		req.util = DIV_ROUND_CLOSEST_ULL(req.util, UCLAMP_PERCENT_SCALE);
+	}
+
+	return req;
+}
+
+static ssize_t cpu_uclamp_write(struct kernfs_open_file *of, char *buf,
+				size_t nbytes, loff_t off,
+				enum uclamp_id clamp_id)
+{
+	struct uclamp_request req;
+	struct task_group *tg;
+
+	req = capacity_from_percent(buf);
+	if (req.ret)
+		return req.ret;
+
+	static_branch_enable(&sched_uclamp_used);
+
+	mutex_lock(&uclamp_mutex);
+	rcu_read_lock();
+
+	tg = css_tg(of_css(of));
+	if (tg->uclamp_req[clamp_id].value != req.util)
+		uclamp_se_set(&tg->uclamp_req[clamp_id], req.util, false);
+
+	/*
+	 * Because of not recoverable conversion rounding we keep track of the
+	 * exact requested value
+	 */
+	tg->uclamp_pct[clamp_id] = req.percent;
+
+	/* Update effective clamps to track the most restrictive value */
+	cpu_util_update_eff(of_css(of));
+
+	rcu_read_unlock();
+	mutex_unlock(&uclamp_mutex);
+
+	return nbytes;
+}
+
+static ssize_t cpu_uclamp_min_write(struct kernfs_open_file *of,
+				    char *buf, size_t nbytes,
+				    loff_t off)
+{
+	return cpu_uclamp_write(of, buf, nbytes, off, UCLAMP_MIN);
+}
+
+static ssize_t cpu_uclamp_max_write(struct kernfs_open_file *of,
+				    char *buf, size_t nbytes,
+				    loff_t off)
+{
+	return cpu_uclamp_write(of, buf, nbytes, off, UCLAMP_MAX);
+}
+
+static inline void cpu_uclamp_print(struct seq_file *sf,
+				    enum uclamp_id clamp_id)
+{
+	struct task_group *tg;
+	u64 util_clamp;
+	u64 percent;
+	u32 rem;
+
+	rcu_read_lock();
+	tg = css_tg(seq_css(sf));
+	util_clamp = tg->uclamp_req[clamp_id].value;
+	rcu_read_unlock();
+
+	if (util_clamp == SCHED_CAPACITY_SCALE) {
+		seq_puts(sf, "max\n");
+		return;
+	}
+
+	percent = tg->uclamp_pct[clamp_id];
+	percent = div_u64_rem(percent, POW10(UCLAMP_PERCENT_SHIFT), &rem);
+	seq_printf(sf, "%llu.%0*u\n", percent, UCLAMP_PERCENT_SHIFT, rem);
+}
+
+static int cpu_uclamp_min_show(struct seq_file *sf, void *v)
+{
+	cpu_uclamp_print(sf, UCLAMP_MIN);
+	return 0;
+}
+
+static int cpu_uclamp_max_show(struct seq_file *sf, void *v)
+{
+	cpu_uclamp_print(sf, UCLAMP_MAX);
+	return 0;
+}
+#endif /* CONFIG_UCLAMP_TASK_GROUP */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static int cpu_shares_write_u64(struct cgroup_subsys_state *css,
+				struct cftype *cftype, u64 shareval)
+{
+	if (shareval > scale_load_down(ULONG_MAX))
+		shareval = MAX_SHARES;
+	return sched_group_set_shares(css_tg(css), scale_load(shareval));
+}
+
+static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css,
+			       struct cftype *cft)
+{
+	struct task_group *tg = css_tg(css);
+
+	return (u64) scale_load_down(tg->shares);
+}
+
+#ifdef CONFIG_CFS_BANDWIDTH
+static DEFINE_MUTEX(cfs_constraints_mutex);
+
+const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */
+static const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */
+/* More than 203 days if BW_SHIFT equals 20. */
+static const u64 max_cfs_runtime = MAX_BW * NSEC_PER_USEC;
+
+static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime);
+
+static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota,
+				u64 burst)
+{
+	int i, ret = 0, runtime_enabled, runtime_was_enabled;
+	struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
+
+	if (tg == &root_task_group)
+		return -EINVAL;
+
+	/*
+	 * Ensure we have at some amount of bandwidth every period.  This is
+	 * to prevent reaching a state of large arrears when throttled via
+	 * entity_tick() resulting in prolonged exit starvation.
+	 */
+	if (quota < min_cfs_quota_period || period < min_cfs_quota_period)
+		return -EINVAL;
+
+	/*
+	 * Likewise, bound things on the other side by preventing insane quota
+	 * periods.  This also allows us to normalize in computing quota
+	 * feasibility.
+	 */
+	if (period > max_cfs_quota_period)
+		return -EINVAL;
+
+	/*
+	 * Bound quota to defend quota against overflow during bandwidth shift.
+	 */
+	if (quota != RUNTIME_INF && quota > max_cfs_runtime)
+		return -EINVAL;
+
+	if (quota != RUNTIME_INF && (burst > quota ||
+				     burst + quota > max_cfs_runtime))
+		return -EINVAL;
+
+	/*
+	 * Prevent race between setting of cfs_rq->runtime_enabled and
+	 * unthrottle_offline_cfs_rqs().
+	 */
+	cpus_read_lock();
+	mutex_lock(&cfs_constraints_mutex);
+	ret = __cfs_schedulable(tg, period, quota);
+	if (ret)
+		goto out_unlock;
+
+	runtime_enabled = quota != RUNTIME_INF;
+	runtime_was_enabled = cfs_b->quota != RUNTIME_INF;
+	/*
+	 * If we need to toggle cfs_bandwidth_used, off->on must occur
+	 * before making related changes, and on->off must occur afterwards
+	 */
+	if (runtime_enabled && !runtime_was_enabled)
+		cfs_bandwidth_usage_inc();
+	raw_spin_lock_irq(&cfs_b->lock);
+	cfs_b->period = ns_to_ktime(period);
+	cfs_b->quota = quota;
+	cfs_b->burst = burst;
+
+	__refill_cfs_bandwidth_runtime(cfs_b);
+
+	/* Restart the period timer (if active) to handle new period expiry: */
+	if (runtime_enabled)
+		start_cfs_bandwidth(cfs_b);
+
+	raw_spin_unlock_irq(&cfs_b->lock);
+
+	for_each_online_cpu(i) {
+		struct cfs_rq *cfs_rq = tg->cfs_rq[i];
+		struct rq *rq = cfs_rq->rq;
+		struct rq_flags rf;
+
+		rq_lock_irq(rq, &rf);
+		cfs_rq->runtime_enabled = runtime_enabled;
+		cfs_rq->runtime_remaining = 0;
+
+		if (cfs_rq->throttled)
+			unthrottle_cfs_rq(cfs_rq);
+		rq_unlock_irq(rq, &rf);
+	}
+	if (runtime_was_enabled && !runtime_enabled)
+		cfs_bandwidth_usage_dec();
+out_unlock:
+	mutex_unlock(&cfs_constraints_mutex);
+	cpus_read_unlock();
+
+	return ret;
+}
+
+static int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)
+{
+	u64 quota, period, burst;
+
+	period = ktime_to_ns(tg->cfs_bandwidth.period);
+	burst = tg->cfs_bandwidth.burst;
+	if (cfs_quota_us < 0)
+		quota = RUNTIME_INF;
+	else if ((u64)cfs_quota_us <= U64_MAX / NSEC_PER_USEC)
+		quota = (u64)cfs_quota_us * NSEC_PER_USEC;
+	else
+		return -EINVAL;
+
+	return tg_set_cfs_bandwidth(tg, period, quota, burst);
+}
+
+static long tg_get_cfs_quota(struct task_group *tg)
+{
+	u64 quota_us;
+
+	if (tg->cfs_bandwidth.quota == RUNTIME_INF)
+		return -1;
+
+	quota_us = tg->cfs_bandwidth.quota;
+	do_div(quota_us, NSEC_PER_USEC);
+
+	return quota_us;
+}
+
+static int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
+{
+	u64 quota, period, burst;
+
+	if ((u64)cfs_period_us > U64_MAX / NSEC_PER_USEC)
+		return -EINVAL;
+
+	period = (u64)cfs_period_us * NSEC_PER_USEC;
+	quota = tg->cfs_bandwidth.quota;
+	burst = tg->cfs_bandwidth.burst;
+
+	return tg_set_cfs_bandwidth(tg, period, quota, burst);
+}
+
+static long tg_get_cfs_period(struct task_group *tg)
+{
+	u64 cfs_period_us;
+
+	cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period);
+	do_div(cfs_period_us, NSEC_PER_USEC);
+
+	return cfs_period_us;
+}
+
+static int tg_set_cfs_burst(struct task_group *tg, long cfs_burst_us)
+{
+	u64 quota, period, burst;
+
+	if ((u64)cfs_burst_us > U64_MAX / NSEC_PER_USEC)
+		return -EINVAL;
+
+	burst = (u64)cfs_burst_us * NSEC_PER_USEC;
+	period = ktime_to_ns(tg->cfs_bandwidth.period);
+	quota = tg->cfs_bandwidth.quota;
+
+	return tg_set_cfs_bandwidth(tg, period, quota, burst);
+}
+
+static long tg_get_cfs_burst(struct task_group *tg)
+{
+	u64 burst_us;
+
+	burst_us = tg->cfs_bandwidth.burst;
+	do_div(burst_us, NSEC_PER_USEC);
+
+	return burst_us;
+}
+
+static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css,
+				  struct cftype *cft)
+{
+	return tg_get_cfs_quota(css_tg(css));
+}
+
+static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css,
+				   struct cftype *cftype, s64 cfs_quota_us)
+{
+	return tg_set_cfs_quota(css_tg(css), cfs_quota_us);
+}
+
+static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css,
+				   struct cftype *cft)
+{
+	return tg_get_cfs_period(css_tg(css));
+}
+
+static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css,
+				    struct cftype *cftype, u64 cfs_period_us)
+{
+	return tg_set_cfs_period(css_tg(css), cfs_period_us);
+}
+
+static u64 cpu_cfs_burst_read_u64(struct cgroup_subsys_state *css,
+				  struct cftype *cft)
+{
+	return tg_get_cfs_burst(css_tg(css));
+}
+
+static int cpu_cfs_burst_write_u64(struct cgroup_subsys_state *css,
+				   struct cftype *cftype, u64 cfs_burst_us)
+{
+	return tg_set_cfs_burst(css_tg(css), cfs_burst_us);
+}
+
+struct cfs_schedulable_data {
+	struct task_group *tg;
+	u64 period, quota;
+};
+
+/*
+ * normalize group quota/period to be quota/max_period
+ * note: units are usecs
+ */
+static u64 normalize_cfs_quota(struct task_group *tg,
+			       struct cfs_schedulable_data *d)
+{
+	u64 quota, period;
+
+	if (tg == d->tg) {
+		period = d->period;
+		quota = d->quota;
+	} else {
+		period = tg_get_cfs_period(tg);
+		quota = tg_get_cfs_quota(tg);
+	}
+
+	/* note: these should typically be equivalent */
+	if (quota == RUNTIME_INF || quota == -1)
+		return RUNTIME_INF;
+
+	return to_ratio(period, quota);
+}
+
+static int tg_cfs_schedulable_down(struct task_group *tg, void *data)
+{
+	struct cfs_schedulable_data *d = data;
+	struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
+	s64 quota = 0, parent_quota = -1;
+
+	if (!tg->parent) {
+		quota = RUNTIME_INF;
+	} else {
+		struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth;
+
+		quota = normalize_cfs_quota(tg, d);
+		parent_quota = parent_b->hierarchical_quota;
+
+		/*
+		 * Ensure max(child_quota) <= parent_quota.  On cgroup2,
+		 * always take the min.  On cgroup1, only inherit when no
+		 * limit is set:
+		 */
+		if (cgroup_subsys_on_dfl(cpu_cgrp_subsys)) {
+			quota = min(quota, parent_quota);
+		} else {
+			if (quota == RUNTIME_INF)
+				quota = parent_quota;
+			else if (parent_quota != RUNTIME_INF && quota > parent_quota)
+				return -EINVAL;
+		}
+	}
+	cfs_b->hierarchical_quota = quota;
+
+	return 0;
+}
+
+static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
+{
+	int ret;
+	struct cfs_schedulable_data data = {
+		.tg = tg,
+		.period = period,
+		.quota = quota,
+	};
+
+	if (quota != RUNTIME_INF) {
+		do_div(data.period, NSEC_PER_USEC);
+		do_div(data.quota, NSEC_PER_USEC);
+	}
+
+	rcu_read_lock();
+	ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static int cpu_cfs_stat_show(struct seq_file *sf, void *v)
+{
+	struct task_group *tg = css_tg(seq_css(sf));
+	struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
+
+	seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods);
+	seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled);
+	seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time);
+
+	if (schedstat_enabled() && tg != &root_task_group) {
+		struct sched_statistics *stats;
+		u64 ws = 0;
+		int i;
+
+		for_each_possible_cpu(i) {
+			stats = __schedstats_from_se(tg->se[i]);
+			ws += schedstat_val(stats->wait_sum);
+		}
+
+		seq_printf(sf, "wait_sum %llu\n", ws);
+	}
+
+	seq_printf(sf, "nr_bursts %d\n", cfs_b->nr_burst);
+	seq_printf(sf, "burst_time %llu\n", cfs_b->burst_time);
+
+	return 0;
+}
+#endif /* CONFIG_CFS_BANDWIDTH */
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static int cpu_rt_runtime_write(struct cgroup_subsys_state *css,
+				struct cftype *cft, s64 val)
+{
+	return sched_group_set_rt_runtime(css_tg(css), val);
+}
+
+static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css,
+			       struct cftype *cft)
+{
+	return sched_group_rt_runtime(css_tg(css));
+}
+
+static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css,
+				    struct cftype *cftype, u64 rt_period_us)
+{
+	return sched_group_set_rt_period(css_tg(css), rt_period_us);
+}
+
+static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
+				   struct cftype *cft)
+{
+	return sched_group_rt_period(css_tg(css));
+}
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static s64 cpu_idle_read_s64(struct cgroup_subsys_state *css,
+			       struct cftype *cft)
+{
+	return css_tg(css)->idle;
+}
+
+static int cpu_idle_write_s64(struct cgroup_subsys_state *css,
+				struct cftype *cft, s64 idle)
+{
+	return sched_group_set_idle(css_tg(css), idle);
+}
+#endif
+
+static struct cftype cpu_legacy_files[] = {
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	{
+		.name = "shares",
+		.read_u64 = cpu_shares_read_u64,
+		.write_u64 = cpu_shares_write_u64,
+	},
+	{
+		.name = "idle",
+		.read_s64 = cpu_idle_read_s64,
+		.write_s64 = cpu_idle_write_s64,
+	},
+#endif
+#ifdef CONFIG_CFS_BANDWIDTH
+	{
+		.name = "cfs_quota_us",
+		.read_s64 = cpu_cfs_quota_read_s64,
+		.write_s64 = cpu_cfs_quota_write_s64,
+	},
+	{
+		.name = "cfs_period_us",
+		.read_u64 = cpu_cfs_period_read_u64,
+		.write_u64 = cpu_cfs_period_write_u64,
+	},
+	{
+		.name = "cfs_burst_us",
+		.read_u64 = cpu_cfs_burst_read_u64,
+		.write_u64 = cpu_cfs_burst_write_u64,
+	},
+	{
+		.name = "stat",
+		.seq_show = cpu_cfs_stat_show,
+	},
+#endif
+#ifdef CONFIG_RT_GROUP_SCHED
+	{
+		.name = "rt_runtime_us",
+		.read_s64 = cpu_rt_runtime_read,
+		.write_s64 = cpu_rt_runtime_write,
+	},
+	{
+		.name = "rt_period_us",
+		.read_u64 = cpu_rt_period_read_uint,
+		.write_u64 = cpu_rt_period_write_uint,
+	},
+#endif
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+	{
+		.name = "uclamp.min",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cpu_uclamp_min_show,
+		.write = cpu_uclamp_min_write,
+	},
+	{
+		.name = "uclamp.max",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cpu_uclamp_max_show,
+		.write = cpu_uclamp_max_write,
+	},
+#endif
+	{ }	/* Terminate */
+};
+
+static int cpu_extra_stat_show(struct seq_file *sf,
+			       struct cgroup_subsys_state *css)
+{
+#ifdef CONFIG_CFS_BANDWIDTH
+	{
+		struct task_group *tg = css_tg(css);
+		struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
+		u64 throttled_usec, burst_usec;
+
+		throttled_usec = cfs_b->throttled_time;
+		do_div(throttled_usec, NSEC_PER_USEC);
+		burst_usec = cfs_b->burst_time;
+		do_div(burst_usec, NSEC_PER_USEC);
+
+		seq_printf(sf, "nr_periods %d\n"
+			   "nr_throttled %d\n"
+			   "throttled_usec %llu\n"
+			   "nr_bursts %d\n"
+			   "burst_usec %llu\n",
+			   cfs_b->nr_periods, cfs_b->nr_throttled,
+			   throttled_usec, cfs_b->nr_burst, burst_usec);
+	}
+#endif
+	return 0;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static u64 cpu_weight_read_u64(struct cgroup_subsys_state *css,
+			       struct cftype *cft)
+{
+	struct task_group *tg = css_tg(css);
+	u64 weight = scale_load_down(tg->shares);
+
+	return DIV_ROUND_CLOSEST_ULL(weight * CGROUP_WEIGHT_DFL, 1024);
+}
+
+static int cpu_weight_write_u64(struct cgroup_subsys_state *css,
+				struct cftype *cft, u64 weight)
+{
+	/*
+	 * cgroup weight knobs should use the common MIN, DFL and MAX
+	 * values which are 1, 100 and 10000 respectively.  While it loses
+	 * a bit of range on both ends, it maps pretty well onto the shares
+	 * value used by scheduler and the round-trip conversions preserve
+	 * the original value over the entire range.
+	 */
+	if (weight < CGROUP_WEIGHT_MIN || weight > CGROUP_WEIGHT_MAX)
+		return -ERANGE;
+
+	weight = DIV_ROUND_CLOSEST_ULL(weight * 1024, CGROUP_WEIGHT_DFL);
+
+	return sched_group_set_shares(css_tg(css), scale_load(weight));
+}
+
+static s64 cpu_weight_nice_read_s64(struct cgroup_subsys_state *css,
+				    struct cftype *cft)
+{
+	unsigned long weight = scale_load_down(css_tg(css)->shares);
+	int last_delta = INT_MAX;
+	int prio, delta;
+
+	/* find the closest nice value to the current weight */
+	for (prio = 0; prio < ARRAY_SIZE(sched_prio_to_weight); prio++) {
+		delta = abs(sched_prio_to_weight[prio] - weight);
+		if (delta >= last_delta)
+			break;
+		last_delta = delta;
+	}
+
+	return PRIO_TO_NICE(prio - 1 + MAX_RT_PRIO);
+}
+
+static int cpu_weight_nice_write_s64(struct cgroup_subsys_state *css,
+				     struct cftype *cft, s64 nice)
+{
+	unsigned long weight;
+	int idx;
+
+	if (nice < MIN_NICE || nice > MAX_NICE)
+		return -ERANGE;
+
+	idx = NICE_TO_PRIO(nice) - MAX_RT_PRIO;
+	idx = array_index_nospec(idx, 40);
+	weight = sched_prio_to_weight[idx];
+
+	return sched_group_set_shares(css_tg(css), scale_load(weight));
+}
+#endif
+
+static void __maybe_unused cpu_period_quota_print(struct seq_file *sf,
+						  long period, long quota)
+{
+	if (quota < 0)
+		seq_puts(sf, "max");
+	else
+		seq_printf(sf, "%ld", quota);
+
+	seq_printf(sf, " %ld\n", period);
+}
+
+/* caller should put the current value in *@periodp before calling */
+static int __maybe_unused cpu_period_quota_parse(char *buf,
+						 u64 *periodp, u64 *quotap)
+{
+	char tok[21];	/* U64_MAX */
+
+	if (sscanf(buf, "%20s %llu", tok, periodp) < 1)
+		return -EINVAL;
+
+	*periodp *= NSEC_PER_USEC;
+
+	if (sscanf(tok, "%llu", quotap))
+		*quotap *= NSEC_PER_USEC;
+	else if (!strcmp(tok, "max"))
+		*quotap = RUNTIME_INF;
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+#ifdef CONFIG_CFS_BANDWIDTH
+static int cpu_max_show(struct seq_file *sf, void *v)
+{
+	struct task_group *tg = css_tg(seq_css(sf));
+
+	cpu_period_quota_print(sf, tg_get_cfs_period(tg), tg_get_cfs_quota(tg));
+	return 0;
+}
+
+static ssize_t cpu_max_write(struct kernfs_open_file *of,
+			     char *buf, size_t nbytes, loff_t off)
+{
+	struct task_group *tg = css_tg(of_css(of));
+	u64 period = tg_get_cfs_period(tg);
+	u64 burst = tg_get_cfs_burst(tg);
+	u64 quota;
+	int ret;
+
+	ret = cpu_period_quota_parse(buf, &period, &quota);
+	if (!ret)
+		ret = tg_set_cfs_bandwidth(tg, period, quota, burst);
+	return ret ?: nbytes;
+}
+#endif
+
+static struct cftype cpu_files[] = {
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	{
+		.name = "weight",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_u64 = cpu_weight_read_u64,
+		.write_u64 = cpu_weight_write_u64,
+	},
+	{
+		.name = "weight.nice",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_s64 = cpu_weight_nice_read_s64,
+		.write_s64 = cpu_weight_nice_write_s64,
+	},
+	{
+		.name = "idle",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_s64 = cpu_idle_read_s64,
+		.write_s64 = cpu_idle_write_s64,
+	},
+#endif
+#ifdef CONFIG_CFS_BANDWIDTH
+	{
+		.name = "max",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cpu_max_show,
+		.write = cpu_max_write,
+	},
+	{
+		.name = "max.burst",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_u64 = cpu_cfs_burst_read_u64,
+		.write_u64 = cpu_cfs_burst_write_u64,
+	},
+#endif
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+	{
+		.name = "uclamp.min",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cpu_uclamp_min_show,
+		.write = cpu_uclamp_min_write,
+	},
+	{
+		.name = "uclamp.max",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = cpu_uclamp_max_show,
+		.write = cpu_uclamp_max_write,
+	},
+#endif
+	{ }	/* terminate */
+};
+
+struct cgroup_subsys cpu_cgrp_subsys = {
+	.css_alloc	= cpu_cgroup_css_alloc,
+	.css_online	= cpu_cgroup_css_online,
+	.css_released	= cpu_cgroup_css_released,
+	.css_free	= cpu_cgroup_css_free,
+	.css_extra_stat_show = cpu_extra_stat_show,
+#ifdef CONFIG_RT_GROUP_SCHED
+	.can_attach	= cpu_cgroup_can_attach,
+#endif
+	.attach		= cpu_cgroup_attach,
+	.legacy_cftypes	= cpu_legacy_files,
+	.dfl_cftypes	= cpu_files,
+	.early_init	= true,
+	.threaded	= true,
+};
+
+#endif	/* CONFIG_CGROUP_SCHED */
+
+void dump_cpu_task(int cpu)
+{
+	if (cpu == smp_processor_id() && in_hardirq()) {
+		struct pt_regs *regs;
+
+		regs = get_irq_regs();
+		if (regs) {
+			show_regs(regs);
+			return;
+		}
+	}
+
+	if (trigger_single_cpu_backtrace(cpu))
+		return;
+
+	pr_info("Task dump for CPU %d:\n", cpu);
+	sched_show_task(cpu_curr(cpu));
+}
+
+/*
+ * Nice levels are multiplicative, with a gentle 10% change for every
+ * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
+ * nice 1, it will get ~10% less CPU time than another CPU-bound task
+ * that remained on nice 0.
+ *
+ * The "10% effect" is relative and cumulative: from _any_ nice level,
+ * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
+ * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
+ * If a task goes up by ~10% and another task goes down by ~10% then
+ * the relative distance between them is ~25%.)
+ */
+const int sched_prio_to_weight[40] = {
+ /* -20 */     88761,     71755,     56483,     46273,     36291,
+ /* -15 */     29154,     23254,     18705,     14949,     11916,
+ /* -10 */      9548,      7620,      6100,      4904,      3906,
+ /*  -5 */      3121,      2501,      1991,      1586,      1277,
+ /*   0 */      1024,       820,       655,       526,       423,
+ /*   5 */       335,       272,       215,       172,       137,
+ /*  10 */       110,        87,        70,        56,        45,
+ /*  15 */        36,        29,        23,        18,        15,
+};
+
+/*
+ * Inverse (2^32/x) values of the sched_prio_to_weight[] array, precalculated.
+ *
+ * In cases where the weight does not change often, we can use the
+ * precalculated inverse to speed up arithmetics by turning divisions
+ * into multiplications:
+ */
+const u32 sched_prio_to_wmult[40] = {
+ /* -20 */     48388,     59856,     76040,     92818,    118348,
+ /* -15 */    147320,    184698,    229616,    287308,    360437,
+ /* -10 */    449829,    563644,    704093,    875809,   1099582,
+ /*  -5 */   1376151,   1717300,   2157191,   2708050,   3363326,
+ /*   0 */   4194304,   5237765,   6557202,   8165337,  10153587,
+ /*   5 */  12820798,  15790321,  19976592,  24970740,  31350126,
+ /*  10 */  39045157,  49367440,  61356676,  76695844,  95443717,
+ /*  15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
+};
+
+void call_trace_sched_update_nr_running(struct rq *rq, int count)
+{
+        trace_sched_update_nr_running_tp(rq, count);
+}
diff --git a/kernel/sched/core_sched.c b/kernel/sched/core_sched.c
new file mode 100644
index 000000000..a57fd8f27
--- /dev/null
+++ b/kernel/sched/core_sched.c
@@ -0,0 +1,300 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * A simple wrapper around refcount. An allocated sched_core_cookie's
+ * address is used to compute the cookie of the task.
+ */
+struct sched_core_cookie {
+	refcount_t refcnt;
+};
+
+static unsigned long sched_core_alloc_cookie(void)
+{
+	struct sched_core_cookie *ck = kmalloc(sizeof(*ck), GFP_KERNEL);
+	if (!ck)
+		return 0;
+
+	refcount_set(&ck->refcnt, 1);
+	sched_core_get();
+
+	return (unsigned long)ck;
+}
+
+static void sched_core_put_cookie(unsigned long cookie)
+{
+	struct sched_core_cookie *ptr = (void *)cookie;
+
+	if (ptr && refcount_dec_and_test(&ptr->refcnt)) {
+		kfree(ptr);
+		sched_core_put();
+	}
+}
+
+static unsigned long sched_core_get_cookie(unsigned long cookie)
+{
+	struct sched_core_cookie *ptr = (void *)cookie;
+
+	if (ptr)
+		refcount_inc(&ptr->refcnt);
+
+	return cookie;
+}
+
+/*
+ * sched_core_update_cookie - replace the cookie on a task
+ * @p: the task to update
+ * @cookie: the new cookie
+ *
+ * Effectively exchange the task cookie; caller is responsible for lifetimes on
+ * both ends.
+ *
+ * Returns: the old cookie
+ */
+static unsigned long sched_core_update_cookie(struct task_struct *p,
+					      unsigned long cookie)
+{
+	unsigned long old_cookie;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(p, &rf);
+
+	/*
+	 * Since creating a cookie implies sched_core_get(), and we cannot set
+	 * a cookie until after we've created it, similarly, we cannot destroy
+	 * a cookie until after we've removed it, we must have core scheduling
+	 * enabled here.
+	 */
+	SCHED_WARN_ON((p->core_cookie || cookie) && !sched_core_enabled(rq));
+
+	if (sched_core_enqueued(p))
+		sched_core_dequeue(rq, p, DEQUEUE_SAVE);
+
+	old_cookie = p->core_cookie;
+	p->core_cookie = cookie;
+
+	/*
+	 * Consider the cases: !prev_cookie and !cookie.
+	 */
+	if (cookie && task_on_rq_queued(p))
+		sched_core_enqueue(rq, p);
+
+	/*
+	 * If task is currently running, it may not be compatible anymore after
+	 * the cookie change, so enter the scheduler on its CPU to schedule it
+	 * away.
+	 *
+	 * Note that it is possible that as a result of this cookie change, the
+	 * core has now entered/left forced idle state. Defer accounting to the
+	 * next scheduling edge, rather than always forcing a reschedule here.
+	 */
+	if (task_on_cpu(rq, p))
+		resched_curr(rq);
+
+	task_rq_unlock(rq, p, &rf);
+
+	return old_cookie;
+}
+
+static unsigned long sched_core_clone_cookie(struct task_struct *p)
+{
+	unsigned long cookie, flags;
+
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	cookie = sched_core_get_cookie(p->core_cookie);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+
+	return cookie;
+}
+
+void sched_core_fork(struct task_struct *p)
+{
+	RB_CLEAR_NODE(&p->core_node);
+	p->core_cookie = sched_core_clone_cookie(current);
+}
+
+void sched_core_free(struct task_struct *p)
+{
+	sched_core_put_cookie(p->core_cookie);
+}
+
+static void __sched_core_set(struct task_struct *p, unsigned long cookie)
+{
+	cookie = sched_core_get_cookie(cookie);
+	cookie = sched_core_update_cookie(p, cookie);
+	sched_core_put_cookie(cookie);
+}
+
+/* Called from prctl interface: PR_SCHED_CORE */
+int sched_core_share_pid(unsigned int cmd, pid_t pid, enum pid_type type,
+			 unsigned long uaddr)
+{
+	unsigned long cookie = 0, id = 0;
+	struct task_struct *task, *p;
+	struct pid *grp;
+	int err = 0;
+
+	if (!static_branch_likely(&sched_smt_present))
+		return -ENODEV;
+
+	BUILD_BUG_ON(PR_SCHED_CORE_SCOPE_THREAD != PIDTYPE_PID);
+	BUILD_BUG_ON(PR_SCHED_CORE_SCOPE_THREAD_GROUP != PIDTYPE_TGID);
+	BUILD_BUG_ON(PR_SCHED_CORE_SCOPE_PROCESS_GROUP != PIDTYPE_PGID);
+
+	if (type > PIDTYPE_PGID || cmd >= PR_SCHED_CORE_MAX || pid < 0 ||
+	    (cmd != PR_SCHED_CORE_GET && uaddr))
+		return -EINVAL;
+
+	rcu_read_lock();
+	if (pid == 0) {
+		task = current;
+	} else {
+		task = find_task_by_vpid(pid);
+		if (!task) {
+			rcu_read_unlock();
+			return -ESRCH;
+		}
+	}
+	get_task_struct(task);
+	rcu_read_unlock();
+
+	/*
+	 * Check if this process has the right to modify the specified
+	 * process. Use the regular "ptrace_may_access()" checks.
+	 */
+	if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
+		err = -EPERM;
+		goto out;
+	}
+
+	switch (cmd) {
+	case PR_SCHED_CORE_GET:
+		if (type != PIDTYPE_PID || uaddr & 7) {
+			err = -EINVAL;
+			goto out;
+		}
+		cookie = sched_core_clone_cookie(task);
+		if (cookie) {
+			/* XXX improve ? */
+			ptr_to_hashval((void *)cookie, &id);
+		}
+		err = put_user(id, (u64 __user *)uaddr);
+		goto out;
+
+	case PR_SCHED_CORE_CREATE:
+		cookie = sched_core_alloc_cookie();
+		if (!cookie) {
+			err = -ENOMEM;
+			goto out;
+		}
+		break;
+
+	case PR_SCHED_CORE_SHARE_TO:
+		cookie = sched_core_clone_cookie(current);
+		break;
+
+	case PR_SCHED_CORE_SHARE_FROM:
+		if (type != PIDTYPE_PID) {
+			err = -EINVAL;
+			goto out;
+		}
+		cookie = sched_core_clone_cookie(task);
+		__sched_core_set(current, cookie);
+		goto out;
+
+	default:
+		err = -EINVAL;
+		goto out;
+	}
+
+	if (type == PIDTYPE_PID) {
+		__sched_core_set(task, cookie);
+		goto out;
+	}
+
+	read_lock(&tasklist_lock);
+	grp = task_pid_type(task, type);
+
+	do_each_pid_thread(grp, type, p) {
+		if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS)) {
+			err = -EPERM;
+			goto out_tasklist;
+		}
+	} while_each_pid_thread(grp, type, p);
+
+	do_each_pid_thread(grp, type, p) {
+		__sched_core_set(p, cookie);
+	} while_each_pid_thread(grp, type, p);
+out_tasklist:
+	read_unlock(&tasklist_lock);
+
+out:
+	sched_core_put_cookie(cookie);
+	put_task_struct(task);
+	return err;
+}
+
+#ifdef CONFIG_SCHEDSTATS
+
+/* REQUIRES: rq->core's clock recently updated. */
+void __sched_core_account_forceidle(struct rq *rq)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu_of(rq));
+	u64 delta, now = rq_clock(rq->core);
+	struct rq *rq_i;
+	struct task_struct *p;
+	int i;
+
+	lockdep_assert_rq_held(rq);
+
+	WARN_ON_ONCE(!rq->core->core_forceidle_count);
+
+	if (rq->core->core_forceidle_start == 0)
+		return;
+
+	delta = now - rq->core->core_forceidle_start;
+	if (unlikely((s64)delta <= 0))
+		return;
+
+	rq->core->core_forceidle_start = now;
+
+	if (WARN_ON_ONCE(!rq->core->core_forceidle_occupation)) {
+		/* can't be forced idle without a running task */
+	} else if (rq->core->core_forceidle_count > 1 ||
+		   rq->core->core_forceidle_occupation > 1) {
+		/*
+		 * For larger SMT configurations, we need to scale the charged
+		 * forced idle amount since there can be more than one forced
+		 * idle sibling and more than one running cookied task.
+		 */
+		delta *= rq->core->core_forceidle_count;
+		delta = div_u64(delta, rq->core->core_forceidle_occupation);
+	}
+
+	for_each_cpu(i, smt_mask) {
+		rq_i = cpu_rq(i);
+		p = rq_i->core_pick ?: rq_i->curr;
+
+		if (p == rq_i->idle)
+			continue;
+
+		/*
+		 * Note: this will account forceidle to the current cpu, even
+		 * if it comes from our SMT sibling.
+		 */
+		__account_forceidle_time(p, delta);
+	}
+}
+
+void __sched_core_tick(struct rq *rq)
+{
+	if (!rq->core->core_forceidle_count)
+		return;
+
+	if (rq != rq->core)
+		update_rq_clock(rq->core);
+
+	__sched_core_account_forceidle(rq);
+}
+
+#endif /* CONFIG_SCHEDSTATS */
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
new file mode 100644
index 000000000..0de9dda09
--- /dev/null
+++ b/kernel/sched/cpuacct.c
@@ -0,0 +1,363 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * CPU accounting code for task groups.
+ *
+ * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
+ * (balbir@in.ibm.com).
+ */
+
+/* Time spent by the tasks of the CPU accounting group executing in ... */
+enum cpuacct_stat_index {
+	CPUACCT_STAT_USER,	/* ... user mode */
+	CPUACCT_STAT_SYSTEM,	/* ... kernel mode */
+
+	CPUACCT_STAT_NSTATS,
+};
+
+static const char * const cpuacct_stat_desc[] = {
+	[CPUACCT_STAT_USER] = "user",
+	[CPUACCT_STAT_SYSTEM] = "system",
+};
+
+/* track CPU usage of a group of tasks and its child groups */
+struct cpuacct {
+	struct cgroup_subsys_state	css;
+	/* cpuusage holds pointer to a u64-type object on every CPU */
+	u64 __percpu	*cpuusage;
+	struct kernel_cpustat __percpu	*cpustat;
+};
+
+static inline struct cpuacct *css_ca(struct cgroup_subsys_state *css)
+{
+	return css ? container_of(css, struct cpuacct, css) : NULL;
+}
+
+/* Return CPU accounting group to which this task belongs */
+static inline struct cpuacct *task_ca(struct task_struct *tsk)
+{
+	return css_ca(task_css(tsk, cpuacct_cgrp_id));
+}
+
+static inline struct cpuacct *parent_ca(struct cpuacct *ca)
+{
+	return css_ca(ca->css.parent);
+}
+
+static DEFINE_PER_CPU(u64, root_cpuacct_cpuusage);
+static struct cpuacct root_cpuacct = {
+	.cpustat	= &kernel_cpustat,
+	.cpuusage	= &root_cpuacct_cpuusage,
+};
+
+/* Create a new CPU accounting group */
+static struct cgroup_subsys_state *
+cpuacct_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+	struct cpuacct *ca;
+
+	if (!parent_css)
+		return &root_cpuacct.css;
+
+	ca = kzalloc(sizeof(*ca), GFP_KERNEL);
+	if (!ca)
+		goto out;
+
+	ca->cpuusage = alloc_percpu(u64);
+	if (!ca->cpuusage)
+		goto out_free_ca;
+
+	ca->cpustat = alloc_percpu(struct kernel_cpustat);
+	if (!ca->cpustat)
+		goto out_free_cpuusage;
+
+	return &ca->css;
+
+out_free_cpuusage:
+	free_percpu(ca->cpuusage);
+out_free_ca:
+	kfree(ca);
+out:
+	return ERR_PTR(-ENOMEM);
+}
+
+/* Destroy an existing CPU accounting group */
+static void cpuacct_css_free(struct cgroup_subsys_state *css)
+{
+	struct cpuacct *ca = css_ca(css);
+
+	free_percpu(ca->cpustat);
+	free_percpu(ca->cpuusage);
+	kfree(ca);
+}
+
+static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu,
+				 enum cpuacct_stat_index index)
+{
+	u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
+	u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
+	u64 data;
+
+	/*
+	 * We allow index == CPUACCT_STAT_NSTATS here to read
+	 * the sum of usages.
+	 */
+	if (WARN_ON_ONCE(index > CPUACCT_STAT_NSTATS))
+		return 0;
+
+#ifndef CONFIG_64BIT
+	/*
+	 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
+	 */
+	raw_spin_rq_lock_irq(cpu_rq(cpu));
+#endif
+
+	switch (index) {
+	case CPUACCT_STAT_USER:
+		data = cpustat[CPUTIME_USER] + cpustat[CPUTIME_NICE];
+		break;
+	case CPUACCT_STAT_SYSTEM:
+		data = cpustat[CPUTIME_SYSTEM] + cpustat[CPUTIME_IRQ] +
+			cpustat[CPUTIME_SOFTIRQ];
+		break;
+	case CPUACCT_STAT_NSTATS:
+		data = *cpuusage;
+		break;
+	}
+
+#ifndef CONFIG_64BIT
+	raw_spin_rq_unlock_irq(cpu_rq(cpu));
+#endif
+
+	return data;
+}
+
+static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu)
+{
+	u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
+	u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
+
+	/* Don't allow to reset global kernel_cpustat */
+	if (ca == &root_cpuacct)
+		return;
+
+#ifndef CONFIG_64BIT
+	/*
+	 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
+	 */
+	raw_spin_rq_lock_irq(cpu_rq(cpu));
+#endif
+	*cpuusage = 0;
+	cpustat[CPUTIME_USER] = cpustat[CPUTIME_NICE] = 0;
+	cpustat[CPUTIME_SYSTEM] = cpustat[CPUTIME_IRQ] = 0;
+	cpustat[CPUTIME_SOFTIRQ] = 0;
+
+#ifndef CONFIG_64BIT
+	raw_spin_rq_unlock_irq(cpu_rq(cpu));
+#endif
+}
+
+/* Return total CPU usage (in nanoseconds) of a group */
+static u64 __cpuusage_read(struct cgroup_subsys_state *css,
+			   enum cpuacct_stat_index index)
+{
+	struct cpuacct *ca = css_ca(css);
+	u64 totalcpuusage = 0;
+	int i;
+
+	for_each_possible_cpu(i)
+		totalcpuusage += cpuacct_cpuusage_read(ca, i, index);
+
+	return totalcpuusage;
+}
+
+static u64 cpuusage_user_read(struct cgroup_subsys_state *css,
+			      struct cftype *cft)
+{
+	return __cpuusage_read(css, CPUACCT_STAT_USER);
+}
+
+static u64 cpuusage_sys_read(struct cgroup_subsys_state *css,
+			     struct cftype *cft)
+{
+	return __cpuusage_read(css, CPUACCT_STAT_SYSTEM);
+}
+
+static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+	return __cpuusage_read(css, CPUACCT_STAT_NSTATS);
+}
+
+static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft,
+			  u64 val)
+{
+	struct cpuacct *ca = css_ca(css);
+	int cpu;
+
+	/*
+	 * Only allow '0' here to do a reset.
+	 */
+	if (val)
+		return -EINVAL;
+
+	for_each_possible_cpu(cpu)
+		cpuacct_cpuusage_write(ca, cpu);
+
+	return 0;
+}
+
+static int __cpuacct_percpu_seq_show(struct seq_file *m,
+				     enum cpuacct_stat_index index)
+{
+	struct cpuacct *ca = css_ca(seq_css(m));
+	u64 percpu;
+	int i;
+
+	for_each_possible_cpu(i) {
+		percpu = cpuacct_cpuusage_read(ca, i, index);
+		seq_printf(m, "%llu ", (unsigned long long) percpu);
+	}
+	seq_printf(m, "\n");
+	return 0;
+}
+
+static int cpuacct_percpu_user_seq_show(struct seq_file *m, void *V)
+{
+	return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_USER);
+}
+
+static int cpuacct_percpu_sys_seq_show(struct seq_file *m, void *V)
+{
+	return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_SYSTEM);
+}
+
+static int cpuacct_percpu_seq_show(struct seq_file *m, void *V)
+{
+	return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_NSTATS);
+}
+
+static int cpuacct_all_seq_show(struct seq_file *m, void *V)
+{
+	struct cpuacct *ca = css_ca(seq_css(m));
+	int index;
+	int cpu;
+
+	seq_puts(m, "cpu");
+	for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
+		seq_printf(m, " %s", cpuacct_stat_desc[index]);
+	seq_puts(m, "\n");
+
+	for_each_possible_cpu(cpu) {
+		seq_printf(m, "%d", cpu);
+		for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
+			seq_printf(m, " %llu",
+				   cpuacct_cpuusage_read(ca, cpu, index));
+		seq_puts(m, "\n");
+	}
+	return 0;
+}
+
+static int cpuacct_stats_show(struct seq_file *sf, void *v)
+{
+	struct cpuacct *ca = css_ca(seq_css(sf));
+	struct task_cputime cputime;
+	u64 val[CPUACCT_STAT_NSTATS];
+	int cpu;
+	int stat;
+
+	memset(&cputime, 0, sizeof(cputime));
+	for_each_possible_cpu(cpu) {
+		u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
+
+		cputime.utime += cpustat[CPUTIME_USER];
+		cputime.utime += cpustat[CPUTIME_NICE];
+		cputime.stime += cpustat[CPUTIME_SYSTEM];
+		cputime.stime += cpustat[CPUTIME_IRQ];
+		cputime.stime += cpustat[CPUTIME_SOFTIRQ];
+
+		cputime.sum_exec_runtime += *per_cpu_ptr(ca->cpuusage, cpu);
+	}
+
+	cputime_adjust(&cputime, &seq_css(sf)->cgroup->prev_cputime,
+		&val[CPUACCT_STAT_USER], &val[CPUACCT_STAT_SYSTEM]);
+
+	for (stat = 0; stat < CPUACCT_STAT_NSTATS; stat++) {
+		seq_printf(sf, "%s %llu\n", cpuacct_stat_desc[stat],
+			nsec_to_clock_t(val[stat]));
+	}
+
+	return 0;
+}
+
+static struct cftype files[] = {
+	{
+		.name = "usage",
+		.read_u64 = cpuusage_read,
+		.write_u64 = cpuusage_write,
+	},
+	{
+		.name = "usage_user",
+		.read_u64 = cpuusage_user_read,
+	},
+	{
+		.name = "usage_sys",
+		.read_u64 = cpuusage_sys_read,
+	},
+	{
+		.name = "usage_percpu",
+		.seq_show = cpuacct_percpu_seq_show,
+	},
+	{
+		.name = "usage_percpu_user",
+		.seq_show = cpuacct_percpu_user_seq_show,
+	},
+	{
+		.name = "usage_percpu_sys",
+		.seq_show = cpuacct_percpu_sys_seq_show,
+	},
+	{
+		.name = "usage_all",
+		.seq_show = cpuacct_all_seq_show,
+	},
+	{
+		.name = "stat",
+		.seq_show = cpuacct_stats_show,
+	},
+	{ }	/* terminate */
+};
+
+/*
+ * charge this task's execution time to its accounting group.
+ *
+ * called with rq->lock held.
+ */
+void cpuacct_charge(struct task_struct *tsk, u64 cputime)
+{
+	unsigned int cpu = task_cpu(tsk);
+	struct cpuacct *ca;
+
+	lockdep_assert_rq_held(cpu_rq(cpu));
+
+	for (ca = task_ca(tsk); ca; ca = parent_ca(ca))
+		*per_cpu_ptr(ca->cpuusage, cpu) += cputime;
+}
+
+/*
+ * Add user/system time to cpuacct.
+ *
+ * Note: it's the caller that updates the account of the root cgroup.
+ */
+void cpuacct_account_field(struct task_struct *tsk, int index, u64 val)
+{
+	struct cpuacct *ca;
+
+	for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca))
+		__this_cpu_add(ca->cpustat->cpustat[index], val);
+}
+
+struct cgroup_subsys cpuacct_cgrp_subsys = {
+	.css_alloc	= cpuacct_css_alloc,
+	.css_free	= cpuacct_css_free,
+	.legacy_cftypes	= files,
+	.early_init	= true,
+};
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
new file mode 100644
index 000000000..57c92d751
--- /dev/null
+++ b/kernel/sched/cpudeadline.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  kernel/sched/cpudeadline.c
+ *
+ *  Global CPU deadline management
+ *
+ *  Author: Juri Lelli <j.lelli@sssup.it>
+ */
+
+static inline int parent(int i)
+{
+	return (i - 1) >> 1;
+}
+
+static inline int left_child(int i)
+{
+	return (i << 1) + 1;
+}
+
+static inline int right_child(int i)
+{
+	return (i << 1) + 2;
+}
+
+static void cpudl_heapify_down(struct cpudl *cp, int idx)
+{
+	int l, r, largest;
+
+	int orig_cpu = cp->elements[idx].cpu;
+	u64 orig_dl = cp->elements[idx].dl;
+
+	if (left_child(idx) >= cp->size)
+		return;
+
+	/* adapted from lib/prio_heap.c */
+	while (1) {
+		u64 largest_dl;
+
+		l = left_child(idx);
+		r = right_child(idx);
+		largest = idx;
+		largest_dl = orig_dl;
+
+		if ((l < cp->size) && dl_time_before(orig_dl,
+						cp->elements[l].dl)) {
+			largest = l;
+			largest_dl = cp->elements[l].dl;
+		}
+		if ((r < cp->size) && dl_time_before(largest_dl,
+						cp->elements[r].dl))
+			largest = r;
+
+		if (largest == idx)
+			break;
+
+		/* pull largest child onto idx */
+		cp->elements[idx].cpu = cp->elements[largest].cpu;
+		cp->elements[idx].dl = cp->elements[largest].dl;
+		cp->elements[cp->elements[idx].cpu].idx = idx;
+		idx = largest;
+	}
+	/* actual push down of saved original values orig_* */
+	cp->elements[idx].cpu = orig_cpu;
+	cp->elements[idx].dl = orig_dl;
+	cp->elements[cp->elements[idx].cpu].idx = idx;
+}
+
+static void cpudl_heapify_up(struct cpudl *cp, int idx)
+{
+	int p;
+
+	int orig_cpu = cp->elements[idx].cpu;
+	u64 orig_dl = cp->elements[idx].dl;
+
+	if (idx == 0)
+		return;
+
+	do {
+		p = parent(idx);
+		if (dl_time_before(orig_dl, cp->elements[p].dl))
+			break;
+		/* pull parent onto idx */
+		cp->elements[idx].cpu = cp->elements[p].cpu;
+		cp->elements[idx].dl = cp->elements[p].dl;
+		cp->elements[cp->elements[idx].cpu].idx = idx;
+		idx = p;
+	} while (idx != 0);
+	/* actual push up of saved original values orig_* */
+	cp->elements[idx].cpu = orig_cpu;
+	cp->elements[idx].dl = orig_dl;
+	cp->elements[cp->elements[idx].cpu].idx = idx;
+}
+
+static void cpudl_heapify(struct cpudl *cp, int idx)
+{
+	if (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
+				cp->elements[idx].dl))
+		cpudl_heapify_up(cp, idx);
+	else
+		cpudl_heapify_down(cp, idx);
+}
+
+static inline int cpudl_maximum(struct cpudl *cp)
+{
+	return cp->elements[0].cpu;
+}
+
+/*
+ * cpudl_find - find the best (later-dl) CPU in the system
+ * @cp: the cpudl max-heap context
+ * @p: the task
+ * @later_mask: a mask to fill in with the selected CPUs (or NULL)
+ *
+ * Returns: int - CPUs were found
+ */
+int cpudl_find(struct cpudl *cp, struct task_struct *p,
+	       struct cpumask *later_mask)
+{
+	const struct sched_dl_entity *dl_se = &p->dl;
+
+	if (later_mask &&
+	    cpumask_and(later_mask, cp->free_cpus, &p->cpus_mask)) {
+		unsigned long cap, max_cap = 0;
+		int cpu, max_cpu = -1;
+
+		if (!sched_asym_cpucap_active())
+			return 1;
+
+		/* Ensure the capacity of the CPUs fits the task. */
+		for_each_cpu(cpu, later_mask) {
+			if (!dl_task_fits_capacity(p, cpu)) {
+				cpumask_clear_cpu(cpu, later_mask);
+
+				cap = capacity_orig_of(cpu);
+
+				if (cap > max_cap ||
+				    (cpu == task_cpu(p) && cap == max_cap)) {
+					max_cap = cap;
+					max_cpu = cpu;
+				}
+			}
+		}
+
+		if (cpumask_empty(later_mask))
+			cpumask_set_cpu(max_cpu, later_mask);
+
+		return 1;
+	} else {
+		int best_cpu = cpudl_maximum(cp);
+
+		WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
+
+		if (cpumask_test_cpu(best_cpu, &p->cpus_mask) &&
+		    dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
+			if (later_mask)
+				cpumask_set_cpu(best_cpu, later_mask);
+
+			return 1;
+		}
+	}
+	return 0;
+}
+
+/*
+ * cpudl_clear - remove a CPU from the cpudl max-heap
+ * @cp: the cpudl max-heap context
+ * @cpu: the target CPU
+ *
+ * Notes: assumes cpu_rq(cpu)->lock is locked
+ *
+ * Returns: (void)
+ */
+void cpudl_clear(struct cpudl *cp, int cpu)
+{
+	int old_idx, new_cpu;
+	unsigned long flags;
+
+	WARN_ON(!cpu_present(cpu));
+
+	raw_spin_lock_irqsave(&cp->lock, flags);
+
+	old_idx = cp->elements[cpu].idx;
+	if (old_idx == IDX_INVALID) {
+		/*
+		 * Nothing to remove if old_idx was invalid.
+		 * This could happen if a rq_offline_dl is
+		 * called for a CPU without -dl tasks running.
+		 */
+	} else {
+		new_cpu = cp->elements[cp->size - 1].cpu;
+		cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl;
+		cp->elements[old_idx].cpu = new_cpu;
+		cp->size--;
+		cp->elements[new_cpu].idx = old_idx;
+		cp->elements[cpu].idx = IDX_INVALID;
+		cpudl_heapify(cp, old_idx);
+
+		cpumask_set_cpu(cpu, cp->free_cpus);
+	}
+	raw_spin_unlock_irqrestore(&cp->lock, flags);
+}
+
+/*
+ * cpudl_set - update the cpudl max-heap
+ * @cp: the cpudl max-heap context
+ * @cpu: the target CPU
+ * @dl: the new earliest deadline for this CPU
+ *
+ * Notes: assumes cpu_rq(cpu)->lock is locked
+ *
+ * Returns: (void)
+ */
+void cpudl_set(struct cpudl *cp, int cpu, u64 dl)
+{
+	int old_idx;
+	unsigned long flags;
+
+	WARN_ON(!cpu_present(cpu));
+
+	raw_spin_lock_irqsave(&cp->lock, flags);
+
+	old_idx = cp->elements[cpu].idx;
+	if (old_idx == IDX_INVALID) {
+		int new_idx = cp->size++;
+
+		cp->elements[new_idx].dl = dl;
+		cp->elements[new_idx].cpu = cpu;
+		cp->elements[cpu].idx = new_idx;
+		cpudl_heapify_up(cp, new_idx);
+		cpumask_clear_cpu(cpu, cp->free_cpus);
+	} else {
+		cp->elements[old_idx].dl = dl;
+		cpudl_heapify(cp, old_idx);
+	}
+
+	raw_spin_unlock_irqrestore(&cp->lock, flags);
+}
+
+/*
+ * cpudl_set_freecpu - Set the cpudl.free_cpus
+ * @cp: the cpudl max-heap context
+ * @cpu: rd attached CPU
+ */
+void cpudl_set_freecpu(struct cpudl *cp, int cpu)
+{
+	cpumask_set_cpu(cpu, cp->free_cpus);
+}
+
+/*
+ * cpudl_clear_freecpu - Clear the cpudl.free_cpus
+ * @cp: the cpudl max-heap context
+ * @cpu: rd attached CPU
+ */
+void cpudl_clear_freecpu(struct cpudl *cp, int cpu)
+{
+	cpumask_clear_cpu(cpu, cp->free_cpus);
+}
+
+/*
+ * cpudl_init - initialize the cpudl structure
+ * @cp: the cpudl max-heap context
+ */
+int cpudl_init(struct cpudl *cp)
+{
+	int i;
+
+	raw_spin_lock_init(&cp->lock);
+	cp->size = 0;
+
+	cp->elements = kcalloc(nr_cpu_ids,
+			       sizeof(struct cpudl_item),
+			       GFP_KERNEL);
+	if (!cp->elements)
+		return -ENOMEM;
+
+	if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {
+		kfree(cp->elements);
+		return -ENOMEM;
+	}
+
+	for_each_possible_cpu(i)
+		cp->elements[i].idx = IDX_INVALID;
+
+	return 0;
+}
+
+/*
+ * cpudl_cleanup - clean up the cpudl structure
+ * @cp: the cpudl max-heap context
+ */
+void cpudl_cleanup(struct cpudl *cp)
+{
+	free_cpumask_var(cp->free_cpus);
+	kfree(cp->elements);
+}
diff --git a/kernel/sched/cpudeadline.h b/kernel/sched/cpudeadline.h
new file mode 100644
index 000000000..0adeda93b
--- /dev/null
+++ b/kernel/sched/cpudeadline.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#define IDX_INVALID		-1
+
+struct cpudl_item {
+	u64			dl;
+	int			cpu;
+	int			idx;
+};
+
+struct cpudl {
+	raw_spinlock_t		lock;
+	int			size;
+	cpumask_var_t		free_cpus;
+	struct cpudl_item	*elements;
+};
+
+#ifdef CONFIG_SMP
+int  cpudl_find(struct cpudl *cp, struct task_struct *p, struct cpumask *later_mask);
+void cpudl_set(struct cpudl *cp, int cpu, u64 dl);
+void cpudl_clear(struct cpudl *cp, int cpu);
+int  cpudl_init(struct cpudl *cp);
+void cpudl_set_freecpu(struct cpudl *cp, int cpu);
+void cpudl_clear_freecpu(struct cpudl *cp, int cpu);
+void cpudl_cleanup(struct cpudl *cp);
+#endif /* CONFIG_SMP */
diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c
new file mode 100644
index 000000000..5252fb191
--- /dev/null
+++ b/kernel/sched/cpufreq.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Scheduler code and data structures related to cpufreq.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ */
+
+DEFINE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
+
+/**
+ * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer.
+ * @cpu: The CPU to set the pointer for.
+ * @data: New pointer value.
+ * @func: Callback function to set for the CPU.
+ *
+ * Set and publish the update_util_data pointer for the given CPU.
+ *
+ * The update_util_data pointer of @cpu is set to @data and the callback
+ * function pointer in the target struct update_util_data is set to @func.
+ * That function will be called by cpufreq_update_util() from RCU-sched
+ * read-side critical sections, so it must not sleep.  @data will always be
+ * passed to it as the first argument which allows the function to get to the
+ * target update_util_data structure and its container.
+ *
+ * The update_util_data pointer of @cpu must be NULL when this function is
+ * called or it will WARN() and return with no effect.
+ */
+void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data,
+			void (*func)(struct update_util_data *data, u64 time,
+				     unsigned int flags))
+{
+	if (WARN_ON(!data || !func))
+		return;
+
+	if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu)))
+		return;
+
+	data->func = func;
+	rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data);
+}
+EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook);
+
+/**
+ * cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer.
+ * @cpu: The CPU to clear the pointer for.
+ *
+ * Clear the update_util_data pointer for the given CPU.
+ *
+ * Callers must use RCU callbacks to free any memory that might be
+ * accessed via the old update_util_data pointer or invoke synchronize_rcu()
+ * right after this function to avoid use-after-free.
+ */
+void cpufreq_remove_update_util_hook(int cpu)
+{
+	rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL);
+}
+EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook);
+
+/**
+ * cpufreq_this_cpu_can_update - Check if cpufreq policy can be updated.
+ * @policy: cpufreq policy to check.
+ *
+ * Return 'true' if:
+ * - the local and remote CPUs share @policy,
+ * - dvfs_possible_from_any_cpu is set in @policy and the local CPU is not going
+ *   offline (in which case it is not expected to run cpufreq updates any more).
+ */
+bool cpufreq_this_cpu_can_update(struct cpufreq_policy *policy)
+{
+	return cpumask_test_cpu(smp_processor_id(), policy->cpus) ||
+		(policy->dvfs_possible_from_any_cpu &&
+		 rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data)));
+}
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
new file mode 100644
index 000000000..853a07618
--- /dev/null
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -0,0 +1,863 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CPUFreq governor based on scheduler-provided CPU utilization data.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ */
+
+#define IOWAIT_BOOST_MIN	(SCHED_CAPACITY_SCALE / 8)
+
+struct sugov_tunables {
+	struct gov_attr_set	attr_set;
+	unsigned int		rate_limit_us;
+};
+
+struct sugov_policy {
+	struct cpufreq_policy	*policy;
+
+	struct sugov_tunables	*tunables;
+	struct list_head	tunables_hook;
+
+	raw_spinlock_t		update_lock;
+	u64			last_freq_update_time;
+	s64			freq_update_delay_ns;
+	unsigned int		next_freq;
+	unsigned int		cached_raw_freq;
+
+	/* The next fields are only needed if fast switch cannot be used: */
+	struct			irq_work irq_work;
+	struct			kthread_work work;
+	struct			mutex work_lock;
+	struct			kthread_worker worker;
+	struct task_struct	*thread;
+	bool			work_in_progress;
+
+	bool			limits_changed;
+	bool			need_freq_update;
+};
+
+struct sugov_cpu {
+	struct update_util_data	update_util;
+	struct sugov_policy	*sg_policy;
+	unsigned int		cpu;
+
+	bool			iowait_boost_pending;
+	unsigned int		iowait_boost;
+	u64			last_update;
+
+	unsigned long		util;
+	unsigned long		bw_dl;
+	unsigned long		max;
+
+	/* The field below is for single-CPU policies only: */
+#ifdef CONFIG_NO_HZ_COMMON
+	unsigned long		saved_idle_calls;
+#endif
+};
+
+static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu);
+
+/************************ Governor internals ***********************/
+
+static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time)
+{
+	s64 delta_ns;
+
+	/*
+	 * Since cpufreq_update_util() is called with rq->lock held for
+	 * the @target_cpu, our per-CPU data is fully serialized.
+	 *
+	 * However, drivers cannot in general deal with cross-CPU
+	 * requests, so while get_next_freq() will work, our
+	 * sugov_update_commit() call may not for the fast switching platforms.
+	 *
+	 * Hence stop here for remote requests if they aren't supported
+	 * by the hardware, as calculating the frequency is pointless if
+	 * we cannot in fact act on it.
+	 *
+	 * This is needed on the slow switching platforms too to prevent CPUs
+	 * going offline from leaving stale IRQ work items behind.
+	 */
+	if (!cpufreq_this_cpu_can_update(sg_policy->policy))
+		return false;
+
+	if (unlikely(sg_policy->limits_changed)) {
+		sg_policy->limits_changed = false;
+		sg_policy->need_freq_update = true;
+		return true;
+	}
+
+	delta_ns = time - sg_policy->last_freq_update_time;
+
+	return delta_ns >= sg_policy->freq_update_delay_ns;
+}
+
+static bool sugov_update_next_freq(struct sugov_policy *sg_policy, u64 time,
+				   unsigned int next_freq)
+{
+	if (sg_policy->need_freq_update)
+		sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS);
+	else if (sg_policy->next_freq == next_freq)
+		return false;
+
+	sg_policy->next_freq = next_freq;
+	sg_policy->last_freq_update_time = time;
+
+	return true;
+}
+
+static void sugov_deferred_update(struct sugov_policy *sg_policy)
+{
+	if (!sg_policy->work_in_progress) {
+		sg_policy->work_in_progress = true;
+		irq_work_queue(&sg_policy->irq_work);
+	}
+}
+
+/**
+ * get_next_freq - Compute a new frequency for a given cpufreq policy.
+ * @sg_policy: schedutil policy object to compute the new frequency for.
+ * @util: Current CPU utilization.
+ * @max: CPU capacity.
+ *
+ * If the utilization is frequency-invariant, choose the new frequency to be
+ * proportional to it, that is
+ *
+ * next_freq = C * max_freq * util / max
+ *
+ * Otherwise, approximate the would-be frequency-invariant utilization by
+ * util_raw * (curr_freq / max_freq) which leads to
+ *
+ * next_freq = C * curr_freq * util_raw / max
+ *
+ * Take C = 1.25 for the frequency tipping point at (util / max) = 0.8.
+ *
+ * The lowest driver-supported frequency which is equal or greater than the raw
+ * next_freq (as calculated above) is returned, subject to policy min/max and
+ * cpufreq driver limitations.
+ */
+static unsigned int get_next_freq(struct sugov_policy *sg_policy,
+				  unsigned long util, unsigned long max)
+{
+	struct cpufreq_policy *policy = sg_policy->policy;
+	unsigned int freq = arch_scale_freq_invariant() ?
+				policy->cpuinfo.max_freq : policy->cur;
+
+	util = map_util_perf(util);
+	freq = map_util_freq(util, freq, max);
+
+	if (freq == sg_policy->cached_raw_freq && !sg_policy->need_freq_update)
+		return sg_policy->next_freq;
+
+	sg_policy->cached_raw_freq = freq;
+	return cpufreq_driver_resolve_freq(policy, freq);
+}
+
+static void sugov_get_util(struct sugov_cpu *sg_cpu)
+{
+	struct rq *rq = cpu_rq(sg_cpu->cpu);
+
+	sg_cpu->max = arch_scale_cpu_capacity(sg_cpu->cpu);
+	sg_cpu->bw_dl = cpu_bw_dl(rq);
+	sg_cpu->util = effective_cpu_util(sg_cpu->cpu, cpu_util_cfs(sg_cpu->cpu),
+					  FREQUENCY_UTIL, NULL);
+}
+
+/**
+ * sugov_iowait_reset() - Reset the IO boost status of a CPU.
+ * @sg_cpu: the sugov data for the CPU to boost
+ * @time: the update time from the caller
+ * @set_iowait_boost: true if an IO boost has been requested
+ *
+ * The IO wait boost of a task is disabled after a tick since the last update
+ * of a CPU. If a new IO wait boost is requested after more then a tick, then
+ * we enable the boost starting from IOWAIT_BOOST_MIN, which improves energy
+ * efficiency by ignoring sporadic wakeups from IO.
+ */
+static bool sugov_iowait_reset(struct sugov_cpu *sg_cpu, u64 time,
+			       bool set_iowait_boost)
+{
+	s64 delta_ns = time - sg_cpu->last_update;
+
+	/* Reset boost only if a tick has elapsed since last request */
+	if (delta_ns <= TICK_NSEC)
+		return false;
+
+	sg_cpu->iowait_boost = set_iowait_boost ? IOWAIT_BOOST_MIN : 0;
+	sg_cpu->iowait_boost_pending = set_iowait_boost;
+
+	return true;
+}
+
+/**
+ * sugov_iowait_boost() - Updates the IO boost status of a CPU.
+ * @sg_cpu: the sugov data for the CPU to boost
+ * @time: the update time from the caller
+ * @flags: SCHED_CPUFREQ_IOWAIT if the task is waking up after an IO wait
+ *
+ * Each time a task wakes up after an IO operation, the CPU utilization can be
+ * boosted to a certain utilization which doubles at each "frequent and
+ * successive" wakeup from IO, ranging from IOWAIT_BOOST_MIN to the utilization
+ * of the maximum OPP.
+ *
+ * To keep doubling, an IO boost has to be requested at least once per tick,
+ * otherwise we restart from the utilization of the minimum OPP.
+ */
+static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
+			       unsigned int flags)
+{
+	bool set_iowait_boost = flags & SCHED_CPUFREQ_IOWAIT;
+
+	/* Reset boost if the CPU appears to have been idle enough */
+	if (sg_cpu->iowait_boost &&
+	    sugov_iowait_reset(sg_cpu, time, set_iowait_boost))
+		return;
+
+	/* Boost only tasks waking up after IO */
+	if (!set_iowait_boost)
+		return;
+
+	/* Ensure boost doubles only one time at each request */
+	if (sg_cpu->iowait_boost_pending)
+		return;
+	sg_cpu->iowait_boost_pending = true;
+
+	/* Double the boost at each request */
+	if (sg_cpu->iowait_boost) {
+		sg_cpu->iowait_boost =
+			min_t(unsigned int, sg_cpu->iowait_boost << 1, SCHED_CAPACITY_SCALE);
+		return;
+	}
+
+	/* First wakeup after IO: start with minimum boost */
+	sg_cpu->iowait_boost = IOWAIT_BOOST_MIN;
+}
+
+/**
+ * sugov_iowait_apply() - Apply the IO boost to a CPU.
+ * @sg_cpu: the sugov data for the cpu to boost
+ * @time: the update time from the caller
+ *
+ * A CPU running a task which woken up after an IO operation can have its
+ * utilization boosted to speed up the completion of those IO operations.
+ * The IO boost value is increased each time a task wakes up from IO, in
+ * sugov_iowait_apply(), and it's instead decreased by this function,
+ * each time an increase has not been requested (!iowait_boost_pending).
+ *
+ * A CPU which also appears to have been idle for at least one tick has also
+ * its IO boost utilization reset.
+ *
+ * This mechanism is designed to boost high frequently IO waiting tasks, while
+ * being more conservative on tasks which does sporadic IO operations.
+ */
+static void sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time)
+{
+	unsigned long boost;
+
+	/* No boost currently required */
+	if (!sg_cpu->iowait_boost)
+		return;
+
+	/* Reset boost if the CPU appears to have been idle enough */
+	if (sugov_iowait_reset(sg_cpu, time, false))
+		return;
+
+	if (!sg_cpu->iowait_boost_pending) {
+		/*
+		 * No boost pending; reduce the boost value.
+		 */
+		sg_cpu->iowait_boost >>= 1;
+		if (sg_cpu->iowait_boost < IOWAIT_BOOST_MIN) {
+			sg_cpu->iowait_boost = 0;
+			return;
+		}
+	}
+
+	sg_cpu->iowait_boost_pending = false;
+
+	/*
+	 * sg_cpu->util is already in capacity scale; convert iowait_boost
+	 * into the same scale so we can compare.
+	 */
+	boost = (sg_cpu->iowait_boost * sg_cpu->max) >> SCHED_CAPACITY_SHIFT;
+	boost = uclamp_rq_util_with(cpu_rq(sg_cpu->cpu), boost, NULL);
+	if (sg_cpu->util < boost)
+		sg_cpu->util = boost;
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
+{
+	unsigned long idle_calls = tick_nohz_get_idle_calls_cpu(sg_cpu->cpu);
+	bool ret = idle_calls == sg_cpu->saved_idle_calls;
+
+	sg_cpu->saved_idle_calls = idle_calls;
+	return ret;
+}
+#else
+static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
+#endif /* CONFIG_NO_HZ_COMMON */
+
+/*
+ * Make sugov_should_update_freq() ignore the rate limit when DL
+ * has increased the utilization.
+ */
+static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu)
+{
+	if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl)
+		sg_cpu->sg_policy->limits_changed = true;
+}
+
+static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu,
+					      u64 time, unsigned int flags)
+{
+	sugov_iowait_boost(sg_cpu, time, flags);
+	sg_cpu->last_update = time;
+
+	ignore_dl_rate_limit(sg_cpu);
+
+	if (!sugov_should_update_freq(sg_cpu->sg_policy, time))
+		return false;
+
+	sugov_get_util(sg_cpu);
+	sugov_iowait_apply(sg_cpu, time);
+
+	return true;
+}
+
+static void sugov_update_single_freq(struct update_util_data *hook, u64 time,
+				     unsigned int flags)
+{
+	struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
+	struct sugov_policy *sg_policy = sg_cpu->sg_policy;
+	unsigned int cached_freq = sg_policy->cached_raw_freq;
+	unsigned int next_f;
+
+	if (!sugov_update_single_common(sg_cpu, time, flags))
+		return;
+
+	next_f = get_next_freq(sg_policy, sg_cpu->util, sg_cpu->max);
+	/*
+	 * Do not reduce the frequency if the CPU has not been idle
+	 * recently, as the reduction is likely to be premature then.
+	 *
+	 * Except when the rq is capped by uclamp_max.
+	 */
+	if (!uclamp_rq_is_capped(cpu_rq(sg_cpu->cpu)) &&
+	    sugov_cpu_is_busy(sg_cpu) && next_f < sg_policy->next_freq &&
+	    !sg_policy->need_freq_update) {
+		next_f = sg_policy->next_freq;
+
+		/* Restore cached freq as next_freq has changed */
+		sg_policy->cached_raw_freq = cached_freq;
+	}
+
+	if (!sugov_update_next_freq(sg_policy, time, next_f))
+		return;
+
+	/*
+	 * This code runs under rq->lock for the target CPU, so it won't run
+	 * concurrently on two different CPUs for the same target and it is not
+	 * necessary to acquire the lock in the fast switch case.
+	 */
+	if (sg_policy->policy->fast_switch_enabled) {
+		cpufreq_driver_fast_switch(sg_policy->policy, next_f);
+	} else {
+		raw_spin_lock(&sg_policy->update_lock);
+		sugov_deferred_update(sg_policy);
+		raw_spin_unlock(&sg_policy->update_lock);
+	}
+}
+
+static void sugov_update_single_perf(struct update_util_data *hook, u64 time,
+				     unsigned int flags)
+{
+	struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
+	unsigned long prev_util = sg_cpu->util;
+
+	/*
+	 * Fall back to the "frequency" path if frequency invariance is not
+	 * supported, because the direct mapping between the utilization and
+	 * the performance levels depends on the frequency invariance.
+	 */
+	if (!arch_scale_freq_invariant()) {
+		sugov_update_single_freq(hook, time, flags);
+		return;
+	}
+
+	if (!sugov_update_single_common(sg_cpu, time, flags))
+		return;
+
+	/*
+	 * Do not reduce the target performance level if the CPU has not been
+	 * idle recently, as the reduction is likely to be premature then.
+	 *
+	 * Except when the rq is capped by uclamp_max.
+	 */
+	if (!uclamp_rq_is_capped(cpu_rq(sg_cpu->cpu)) &&
+	    sugov_cpu_is_busy(sg_cpu) && sg_cpu->util < prev_util)
+		sg_cpu->util = prev_util;
+
+	cpufreq_driver_adjust_perf(sg_cpu->cpu, map_util_perf(sg_cpu->bw_dl),
+				   map_util_perf(sg_cpu->util), sg_cpu->max);
+
+	sg_cpu->sg_policy->last_freq_update_time = time;
+}
+
+static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
+{
+	struct sugov_policy *sg_policy = sg_cpu->sg_policy;
+	struct cpufreq_policy *policy = sg_policy->policy;
+	unsigned long util = 0, max = 1;
+	unsigned int j;
+
+	for_each_cpu(j, policy->cpus) {
+		struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
+		unsigned long j_util, j_max;
+
+		sugov_get_util(j_sg_cpu);
+		sugov_iowait_apply(j_sg_cpu, time);
+		j_util = j_sg_cpu->util;
+		j_max = j_sg_cpu->max;
+
+		if (j_util * max > j_max * util) {
+			util = j_util;
+			max = j_max;
+		}
+	}
+
+	return get_next_freq(sg_policy, util, max);
+}
+
+static void
+sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags)
+{
+	struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
+	struct sugov_policy *sg_policy = sg_cpu->sg_policy;
+	unsigned int next_f;
+
+	raw_spin_lock(&sg_policy->update_lock);
+
+	sugov_iowait_boost(sg_cpu, time, flags);
+	sg_cpu->last_update = time;
+
+	ignore_dl_rate_limit(sg_cpu);
+
+	if (sugov_should_update_freq(sg_policy, time)) {
+		next_f = sugov_next_freq_shared(sg_cpu, time);
+
+		if (!sugov_update_next_freq(sg_policy, time, next_f))
+			goto unlock;
+
+		if (sg_policy->policy->fast_switch_enabled)
+			cpufreq_driver_fast_switch(sg_policy->policy, next_f);
+		else
+			sugov_deferred_update(sg_policy);
+	}
+unlock:
+	raw_spin_unlock(&sg_policy->update_lock);
+}
+
+static void sugov_work(struct kthread_work *work)
+{
+	struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
+	unsigned int freq;
+	unsigned long flags;
+
+	/*
+	 * Hold sg_policy->update_lock shortly to handle the case where:
+	 * in case sg_policy->next_freq is read here, and then updated by
+	 * sugov_deferred_update() just before work_in_progress is set to false
+	 * here, we may miss queueing the new update.
+	 *
+	 * Note: If a work was queued after the update_lock is released,
+	 * sugov_work() will just be called again by kthread_work code; and the
+	 * request will be proceed before the sugov thread sleeps.
+	 */
+	raw_spin_lock_irqsave(&sg_policy->update_lock, flags);
+	freq = sg_policy->next_freq;
+	sg_policy->work_in_progress = false;
+	raw_spin_unlock_irqrestore(&sg_policy->update_lock, flags);
+
+	mutex_lock(&sg_policy->work_lock);
+	__cpufreq_driver_target(sg_policy->policy, freq, CPUFREQ_RELATION_L);
+	mutex_unlock(&sg_policy->work_lock);
+}
+
+static void sugov_irq_work(struct irq_work *irq_work)
+{
+	struct sugov_policy *sg_policy;
+
+	sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
+
+	kthread_queue_work(&sg_policy->worker, &sg_policy->work);
+}
+
+/************************** sysfs interface ************************/
+
+static struct sugov_tunables *global_tunables;
+static DEFINE_MUTEX(global_tunables_lock);
+
+static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set)
+{
+	return container_of(attr_set, struct sugov_tunables, attr_set);
+}
+
+static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
+{
+	struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
+
+	return sprintf(buf, "%u\n", tunables->rate_limit_us);
+}
+
+static ssize_t
+rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf, size_t count)
+{
+	struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
+	struct sugov_policy *sg_policy;
+	unsigned int rate_limit_us;
+
+	if (kstrtouint(buf, 10, &rate_limit_us))
+		return -EINVAL;
+
+	tunables->rate_limit_us = rate_limit_us;
+
+	list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook)
+		sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC;
+
+	return count;
+}
+
+static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us);
+
+static struct attribute *sugov_attrs[] = {
+	&rate_limit_us.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(sugov);
+
+static void sugov_tunables_free(struct kobject *kobj)
+{
+	struct gov_attr_set *attr_set = to_gov_attr_set(kobj);
+
+	kfree(to_sugov_tunables(attr_set));
+}
+
+static struct kobj_type sugov_tunables_ktype = {
+	.default_groups = sugov_groups,
+	.sysfs_ops = &governor_sysfs_ops,
+	.release = &sugov_tunables_free,
+};
+
+/********************** cpufreq governor interface *********************/
+
+struct cpufreq_governor schedutil_gov;
+
+static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
+{
+	struct sugov_policy *sg_policy;
+
+	sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL);
+	if (!sg_policy)
+		return NULL;
+
+	sg_policy->policy = policy;
+	raw_spin_lock_init(&sg_policy->update_lock);
+	return sg_policy;
+}
+
+static void sugov_policy_free(struct sugov_policy *sg_policy)
+{
+	kfree(sg_policy);
+}
+
+static int sugov_kthread_create(struct sugov_policy *sg_policy)
+{
+	struct task_struct *thread;
+	struct sched_attr attr = {
+		.size		= sizeof(struct sched_attr),
+		.sched_policy	= SCHED_DEADLINE,
+		.sched_flags	= SCHED_FLAG_SUGOV,
+		.sched_nice	= 0,
+		.sched_priority	= 0,
+		/*
+		 * Fake (unused) bandwidth; workaround to "fix"
+		 * priority inheritance.
+		 */
+		.sched_runtime	=  1000000,
+		.sched_deadline = 10000000,
+		.sched_period	= 10000000,
+	};
+	struct cpufreq_policy *policy = sg_policy->policy;
+	int ret;
+
+	/* kthread only required for slow path */
+	if (policy->fast_switch_enabled)
+		return 0;
+
+	kthread_init_work(&sg_policy->work, sugov_work);
+	kthread_init_worker(&sg_policy->worker);
+	thread = kthread_create(kthread_worker_fn, &sg_policy->worker,
+				"sugov:%d",
+				cpumask_first(policy->related_cpus));
+	if (IS_ERR(thread)) {
+		pr_err("failed to create sugov thread: %ld\n", PTR_ERR(thread));
+		return PTR_ERR(thread);
+	}
+
+	ret = sched_setattr_nocheck(thread, &attr);
+	if (ret) {
+		kthread_stop(thread);
+		pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
+		return ret;
+	}
+
+	sg_policy->thread = thread;
+	kthread_bind_mask(thread, policy->related_cpus);
+	init_irq_work(&sg_policy->irq_work, sugov_irq_work);
+	mutex_init(&sg_policy->work_lock);
+
+	wake_up_process(thread);
+
+	return 0;
+}
+
+static void sugov_kthread_stop(struct sugov_policy *sg_policy)
+{
+	/* kthread only required for slow path */
+	if (sg_policy->policy->fast_switch_enabled)
+		return;
+
+	kthread_flush_worker(&sg_policy->worker);
+	kthread_stop(sg_policy->thread);
+	mutex_destroy(&sg_policy->work_lock);
+}
+
+static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy)
+{
+	struct sugov_tunables *tunables;
+
+	tunables = kzalloc(sizeof(*tunables), GFP_KERNEL);
+	if (tunables) {
+		gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook);
+		if (!have_governor_per_policy())
+			global_tunables = tunables;
+	}
+	return tunables;
+}
+
+static void sugov_clear_global_tunables(void)
+{
+	if (!have_governor_per_policy())
+		global_tunables = NULL;
+}
+
+static int sugov_init(struct cpufreq_policy *policy)
+{
+	struct sugov_policy *sg_policy;
+	struct sugov_tunables *tunables;
+	int ret = 0;
+
+	/* State should be equivalent to EXIT */
+	if (policy->governor_data)
+		return -EBUSY;
+
+	cpufreq_enable_fast_switch(policy);
+
+	sg_policy = sugov_policy_alloc(policy);
+	if (!sg_policy) {
+		ret = -ENOMEM;
+		goto disable_fast_switch;
+	}
+
+	ret = sugov_kthread_create(sg_policy);
+	if (ret)
+		goto free_sg_policy;
+
+	mutex_lock(&global_tunables_lock);
+
+	if (global_tunables) {
+		if (WARN_ON(have_governor_per_policy())) {
+			ret = -EINVAL;
+			goto stop_kthread;
+		}
+		policy->governor_data = sg_policy;
+		sg_policy->tunables = global_tunables;
+
+		gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook);
+		goto out;
+	}
+
+	tunables = sugov_tunables_alloc(sg_policy);
+	if (!tunables) {
+		ret = -ENOMEM;
+		goto stop_kthread;
+	}
+
+	tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy);
+
+	policy->governor_data = sg_policy;
+	sg_policy->tunables = tunables;
+
+	ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype,
+				   get_governor_parent_kobj(policy), "%s",
+				   schedutil_gov.name);
+	if (ret)
+		goto fail;
+
+out:
+	mutex_unlock(&global_tunables_lock);
+	return 0;
+
+fail:
+	kobject_put(&tunables->attr_set.kobj);
+	policy->governor_data = NULL;
+	sugov_clear_global_tunables();
+
+stop_kthread:
+	sugov_kthread_stop(sg_policy);
+	mutex_unlock(&global_tunables_lock);
+
+free_sg_policy:
+	sugov_policy_free(sg_policy);
+
+disable_fast_switch:
+	cpufreq_disable_fast_switch(policy);
+
+	pr_err("initialization failed (error %d)\n", ret);
+	return ret;
+}
+
+static void sugov_exit(struct cpufreq_policy *policy)
+{
+	struct sugov_policy *sg_policy = policy->governor_data;
+	struct sugov_tunables *tunables = sg_policy->tunables;
+	unsigned int count;
+
+	mutex_lock(&global_tunables_lock);
+
+	count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
+	policy->governor_data = NULL;
+	if (!count)
+		sugov_clear_global_tunables();
+
+	mutex_unlock(&global_tunables_lock);
+
+	sugov_kthread_stop(sg_policy);
+	sugov_policy_free(sg_policy);
+	cpufreq_disable_fast_switch(policy);
+}
+
+static int sugov_start(struct cpufreq_policy *policy)
+{
+	struct sugov_policy *sg_policy = policy->governor_data;
+	void (*uu)(struct update_util_data *data, u64 time, unsigned int flags);
+	unsigned int cpu;
+
+	sg_policy->freq_update_delay_ns	= sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
+	sg_policy->last_freq_update_time	= 0;
+	sg_policy->next_freq			= 0;
+	sg_policy->work_in_progress		= false;
+	sg_policy->limits_changed		= false;
+	sg_policy->cached_raw_freq		= 0;
+
+	sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS);
+
+	for_each_cpu(cpu, policy->cpus) {
+		struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
+
+		memset(sg_cpu, 0, sizeof(*sg_cpu));
+		sg_cpu->cpu			= cpu;
+		sg_cpu->sg_policy		= sg_policy;
+	}
+
+	if (policy_is_shared(policy))
+		uu = sugov_update_shared;
+	else if (policy->fast_switch_enabled && cpufreq_driver_has_adjust_perf())
+		uu = sugov_update_single_perf;
+	else
+		uu = sugov_update_single_freq;
+
+	for_each_cpu(cpu, policy->cpus) {
+		struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
+
+		cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util, uu);
+	}
+	return 0;
+}
+
+static void sugov_stop(struct cpufreq_policy *policy)
+{
+	struct sugov_policy *sg_policy = policy->governor_data;
+	unsigned int cpu;
+
+	for_each_cpu(cpu, policy->cpus)
+		cpufreq_remove_update_util_hook(cpu);
+
+	synchronize_rcu();
+
+	if (!policy->fast_switch_enabled) {
+		irq_work_sync(&sg_policy->irq_work);
+		kthread_cancel_work_sync(&sg_policy->work);
+	}
+}
+
+static void sugov_limits(struct cpufreq_policy *policy)
+{
+	struct sugov_policy *sg_policy = policy->governor_data;
+
+	if (!policy->fast_switch_enabled) {
+		mutex_lock(&sg_policy->work_lock);
+		cpufreq_policy_apply_limits(policy);
+		mutex_unlock(&sg_policy->work_lock);
+	}
+
+	sg_policy->limits_changed = true;
+}
+
+struct cpufreq_governor schedutil_gov = {
+	.name			= "schedutil",
+	.owner			= THIS_MODULE,
+	.flags			= CPUFREQ_GOV_DYNAMIC_SWITCHING,
+	.init			= sugov_init,
+	.exit			= sugov_exit,
+	.start			= sugov_start,
+	.stop			= sugov_stop,
+	.limits			= sugov_limits,
+};
+
+#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
+struct cpufreq_governor *cpufreq_default_governor(void)
+{
+	return &schedutil_gov;
+}
+#endif
+
+cpufreq_governor_init(schedutil_gov);
+
+#ifdef CONFIG_ENERGY_MODEL
+static void rebuild_sd_workfn(struct work_struct *work)
+{
+	rebuild_sched_domains_energy();
+}
+static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
+
+/*
+ * EAS shouldn't be attempted without sugov, so rebuild the sched_domains
+ * on governor changes to make sure the scheduler knows about it.
+ */
+void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
+				  struct cpufreq_governor *old_gov)
+{
+	if (old_gov == &schedutil_gov || policy->governor == &schedutil_gov) {
+		/*
+		 * When called from the cpufreq_register_driver() path, the
+		 * cpu_hotplug_lock is already held, so use a work item to
+		 * avoid nested locking in rebuild_sched_domains().
+		 */
+		schedule_work(&rebuild_sd_work);
+	}
+
+}
+#endif
diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c
new file mode 100644
index 000000000..42c40cfdf
--- /dev/null
+++ b/kernel/sched/cpupri.c
@@ -0,0 +1,316 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  kernel/sched/cpupri.c
+ *
+ *  CPU priority management
+ *
+ *  Copyright (C) 2007-2008 Novell
+ *
+ *  Author: Gregory Haskins <ghaskins@novell.com>
+ *
+ *  This code tracks the priority of each CPU so that global migration
+ *  decisions are easy to calculate.  Each CPU can be in a state as follows:
+ *
+ *                 (INVALID), NORMAL, RT1, ... RT99, HIGHER
+ *
+ *  going from the lowest priority to the highest.  CPUs in the INVALID state
+ *  are not eligible for routing.  The system maintains this state with
+ *  a 2 dimensional bitmap (the first for priority class, the second for CPUs
+ *  in that class).  Therefore a typical application without affinity
+ *  restrictions can find a suitable CPU with O(1) complexity (e.g. two bit
+ *  searches).  For tasks with affinity restrictions, the algorithm has a
+ *  worst case complexity of O(min(101, nr_domcpus)), though the scenario that
+ *  yields the worst case search is fairly contrived.
+ */
+
+/*
+ * p->rt_priority   p->prio   newpri   cpupri
+ *
+ *				  -1       -1 (CPUPRI_INVALID)
+ *
+ *				  99        0 (CPUPRI_NORMAL)
+ *
+ *		1        98       98        1
+ *	      ...
+ *	       49        50       50       49
+ *	       50        49       49       50
+ *	      ...
+ *	       99         0        0       99
+ *
+ *				 100	  100 (CPUPRI_HIGHER)
+ */
+static int convert_prio(int prio)
+{
+	int cpupri;
+
+	switch (prio) {
+	case CPUPRI_INVALID:
+		cpupri = CPUPRI_INVALID;	/* -1 */
+		break;
+
+	case 0 ... 98:
+		cpupri = MAX_RT_PRIO-1 - prio;	/* 1 ... 99 */
+		break;
+
+	case MAX_RT_PRIO-1:
+		cpupri = CPUPRI_NORMAL;		/*  0 */
+		break;
+
+	case MAX_RT_PRIO:
+		cpupri = CPUPRI_HIGHER;		/* 100 */
+		break;
+	}
+
+	return cpupri;
+}
+
+static inline int __cpupri_find(struct cpupri *cp, struct task_struct *p,
+				struct cpumask *lowest_mask, int idx)
+{
+	struct cpupri_vec *vec  = &cp->pri_to_cpu[idx];
+	int skip = 0;
+
+	if (!atomic_read(&(vec)->count))
+		skip = 1;
+	/*
+	 * When looking at the vector, we need to read the counter,
+	 * do a memory barrier, then read the mask.
+	 *
+	 * Note: This is still all racy, but we can deal with it.
+	 *  Ideally, we only want to look at masks that are set.
+	 *
+	 *  If a mask is not set, then the only thing wrong is that we
+	 *  did a little more work than necessary.
+	 *
+	 *  If we read a zero count but the mask is set, because of the
+	 *  memory barriers, that can only happen when the highest prio
+	 *  task for a run queue has left the run queue, in which case,
+	 *  it will be followed by a pull. If the task we are processing
+	 *  fails to find a proper place to go, that pull request will
+	 *  pull this task if the run queue is running at a lower
+	 *  priority.
+	 */
+	smp_rmb();
+
+	/* Need to do the rmb for every iteration */
+	if (skip)
+		return 0;
+
+	if (cpumask_any_and(&p->cpus_mask, vec->mask) >= nr_cpu_ids)
+		return 0;
+
+	if (lowest_mask) {
+		cpumask_and(lowest_mask, &p->cpus_mask, vec->mask);
+		cpumask_and(lowest_mask, lowest_mask, cpu_active_mask);
+
+		/*
+		 * We have to ensure that we have at least one bit
+		 * still set in the array, since the map could have
+		 * been concurrently emptied between the first and
+		 * second reads of vec->mask.  If we hit this
+		 * condition, simply act as though we never hit this
+		 * priority level and continue on.
+		 */
+		if (cpumask_empty(lowest_mask))
+			return 0;
+	}
+
+	return 1;
+}
+
+int cpupri_find(struct cpupri *cp, struct task_struct *p,
+		struct cpumask *lowest_mask)
+{
+	return cpupri_find_fitness(cp, p, lowest_mask, NULL);
+}
+
+/**
+ * cpupri_find_fitness - find the best (lowest-pri) CPU in the system
+ * @cp: The cpupri context
+ * @p: The task
+ * @lowest_mask: A mask to fill in with selected CPUs (or NULL)
+ * @fitness_fn: A pointer to a function to do custom checks whether the CPU
+ *              fits a specific criteria so that we only return those CPUs.
+ *
+ * Note: This function returns the recommended CPUs as calculated during the
+ * current invocation.  By the time the call returns, the CPUs may have in
+ * fact changed priorities any number of times.  While not ideal, it is not
+ * an issue of correctness since the normal rebalancer logic will correct
+ * any discrepancies created by racing against the uncertainty of the current
+ * priority configuration.
+ *
+ * Return: (int)bool - CPUs were found
+ */
+int cpupri_find_fitness(struct cpupri *cp, struct task_struct *p,
+		struct cpumask *lowest_mask,
+		bool (*fitness_fn)(struct task_struct *p, int cpu))
+{
+	int task_pri = convert_prio(p->prio);
+	int idx, cpu;
+
+	WARN_ON_ONCE(task_pri >= CPUPRI_NR_PRIORITIES);
+
+	for (idx = 0; idx < task_pri; idx++) {
+
+		if (!__cpupri_find(cp, p, lowest_mask, idx))
+			continue;
+
+		if (!lowest_mask || !fitness_fn)
+			return 1;
+
+		/* Ensure the capacity of the CPUs fit the task */
+		for_each_cpu(cpu, lowest_mask) {
+			if (!fitness_fn(p, cpu))
+				cpumask_clear_cpu(cpu, lowest_mask);
+		}
+
+		/*
+		 * If no CPU at the current priority can fit the task
+		 * continue looking
+		 */
+		if (cpumask_empty(lowest_mask))
+			continue;
+
+		return 1;
+	}
+
+	/*
+	 * If we failed to find a fitting lowest_mask, kick off a new search
+	 * but without taking into account any fitness criteria this time.
+	 *
+	 * This rule favours honouring priority over fitting the task in the
+	 * correct CPU (Capacity Awareness being the only user now).
+	 * The idea is that if a higher priority task can run, then it should
+	 * run even if this ends up being on unfitting CPU.
+	 *
+	 * The cost of this trade-off is not entirely clear and will probably
+	 * be good for some workloads and bad for others.
+	 *
+	 * The main idea here is that if some CPUs were over-committed, we try
+	 * to spread which is what the scheduler traditionally did. Sys admins
+	 * must do proper RT planning to avoid overloading the system if they
+	 * really care.
+	 */
+	if (fitness_fn)
+		return cpupri_find(cp, p, lowest_mask);
+
+	return 0;
+}
+
+/**
+ * cpupri_set - update the CPU priority setting
+ * @cp: The cpupri context
+ * @cpu: The target CPU
+ * @newpri: The priority (INVALID,NORMAL,RT1-RT99,HIGHER) to assign to this CPU
+ *
+ * Note: Assumes cpu_rq(cpu)->lock is locked
+ *
+ * Returns: (void)
+ */
+void cpupri_set(struct cpupri *cp, int cpu, int newpri)
+{
+	int *currpri = &cp->cpu_to_pri[cpu];
+	int oldpri = *currpri;
+	int do_mb = 0;
+
+	newpri = convert_prio(newpri);
+
+	BUG_ON(newpri >= CPUPRI_NR_PRIORITIES);
+
+	if (newpri == oldpri)
+		return;
+
+	/*
+	 * If the CPU was currently mapped to a different value, we
+	 * need to map it to the new value then remove the old value.
+	 * Note, we must add the new value first, otherwise we risk the
+	 * cpu being missed by the priority loop in cpupri_find.
+	 */
+	if (likely(newpri != CPUPRI_INVALID)) {
+		struct cpupri_vec *vec = &cp->pri_to_cpu[newpri];
+
+		cpumask_set_cpu(cpu, vec->mask);
+		/*
+		 * When adding a new vector, we update the mask first,
+		 * do a write memory barrier, and then update the count, to
+		 * make sure the vector is visible when count is set.
+		 */
+		smp_mb__before_atomic();
+		atomic_inc(&(vec)->count);
+		do_mb = 1;
+	}
+	if (likely(oldpri != CPUPRI_INVALID)) {
+		struct cpupri_vec *vec  = &cp->pri_to_cpu[oldpri];
+
+		/*
+		 * Because the order of modification of the vec->count
+		 * is important, we must make sure that the update
+		 * of the new prio is seen before we decrement the
+		 * old prio. This makes sure that the loop sees
+		 * one or the other when we raise the priority of
+		 * the run queue. We don't care about when we lower the
+		 * priority, as that will trigger an rt pull anyway.
+		 *
+		 * We only need to do a memory barrier if we updated
+		 * the new priority vec.
+		 */
+		if (do_mb)
+			smp_mb__after_atomic();
+
+		/*
+		 * When removing from the vector, we decrement the counter first
+		 * do a memory barrier and then clear the mask.
+		 */
+		atomic_dec(&(vec)->count);
+		smp_mb__after_atomic();
+		cpumask_clear_cpu(cpu, vec->mask);
+	}
+
+	*currpri = newpri;
+}
+
+/**
+ * cpupri_init - initialize the cpupri structure
+ * @cp: The cpupri context
+ *
+ * Return: -ENOMEM on memory allocation failure.
+ */
+int cpupri_init(struct cpupri *cp)
+{
+	int i;
+
+	for (i = 0; i < CPUPRI_NR_PRIORITIES; i++) {
+		struct cpupri_vec *vec = &cp->pri_to_cpu[i];
+
+		atomic_set(&vec->count, 0);
+		if (!zalloc_cpumask_var(&vec->mask, GFP_KERNEL))
+			goto cleanup;
+	}
+
+	cp->cpu_to_pri = kcalloc(nr_cpu_ids, sizeof(int), GFP_KERNEL);
+	if (!cp->cpu_to_pri)
+		goto cleanup;
+
+	for_each_possible_cpu(i)
+		cp->cpu_to_pri[i] = CPUPRI_INVALID;
+
+	return 0;
+
+cleanup:
+	for (i--; i >= 0; i--)
+		free_cpumask_var(cp->pri_to_cpu[i].mask);
+	return -ENOMEM;
+}
+
+/**
+ * cpupri_cleanup - clean up the cpupri structure
+ * @cp: The cpupri context
+ */
+void cpupri_cleanup(struct cpupri *cp)
+{
+	int i;
+
+	kfree(cp->cpu_to_pri);
+	for (i = 0; i < CPUPRI_NR_PRIORITIES; i++)
+		free_cpumask_var(cp->pri_to_cpu[i].mask);
+}
diff --git a/kernel/sched/cpupri.h b/kernel/sched/cpupri.h
new file mode 100644
index 000000000..d6cba0020
--- /dev/null
+++ b/kernel/sched/cpupri.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#define CPUPRI_NR_PRIORITIES	(MAX_RT_PRIO+1)
+
+#define CPUPRI_INVALID		-1
+#define CPUPRI_NORMAL		 0
+/* values 1-99 are for RT1-RT99 priorities */
+#define CPUPRI_HIGHER		100
+
+struct cpupri_vec {
+	atomic_t		count;
+	cpumask_var_t		mask;
+};
+
+struct cpupri {
+	struct cpupri_vec	pri_to_cpu[CPUPRI_NR_PRIORITIES];
+	int			*cpu_to_pri;
+};
+
+#ifdef CONFIG_SMP
+int  cpupri_find(struct cpupri *cp, struct task_struct *p,
+		 struct cpumask *lowest_mask);
+int  cpupri_find_fitness(struct cpupri *cp, struct task_struct *p,
+			 struct cpumask *lowest_mask,
+			 bool (*fitness_fn)(struct task_struct *p, int cpu));
+void cpupri_set(struct cpupri *cp, int cpu, int pri);
+int  cpupri_init(struct cpupri *cp);
+void cpupri_cleanup(struct cpupri *cp);
+#endif
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
new file mode 100644
index 000000000..95fc77853
--- /dev/null
+++ b/kernel/sched/cputime.c
@@ -0,0 +1,1098 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Simple CPU accounting cgroup controller
+ */
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+
+/*
+ * There are no locks covering percpu hardirq/softirq time.
+ * They are only modified in vtime_account, on corresponding CPU
+ * with interrupts disabled. So, writes are safe.
+ * They are read and saved off onto struct rq in update_rq_clock().
+ * This may result in other CPU reading this CPU's irq time and can
+ * race with irq/vtime_account on this CPU. We would either get old
+ * or new value with a side effect of accounting a slice of irq time to wrong
+ * task when irq is in progress while we read rq->clock. That is a worthy
+ * compromise in place of having locks on each irq in account_system_time.
+ */
+DEFINE_PER_CPU(struct irqtime, cpu_irqtime);
+
+static int sched_clock_irqtime;
+
+void enable_sched_clock_irqtime(void)
+{
+	sched_clock_irqtime = 1;
+}
+
+void disable_sched_clock_irqtime(void)
+{
+	sched_clock_irqtime = 0;
+}
+
+static void irqtime_account_delta(struct irqtime *irqtime, u64 delta,
+				  enum cpu_usage_stat idx)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+
+	u64_stats_update_begin(&irqtime->sync);
+	cpustat[idx] += delta;
+	irqtime->total += delta;
+	irqtime->tick_delta += delta;
+	u64_stats_update_end(&irqtime->sync);
+}
+
+/*
+ * Called after incrementing preempt_count on {soft,}irq_enter
+ * and before decrementing preempt_count on {soft,}irq_exit.
+ */
+void irqtime_account_irq(struct task_struct *curr, unsigned int offset)
+{
+	struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime);
+	unsigned int pc;
+	s64 delta;
+	int cpu;
+
+	if (!sched_clock_irqtime)
+		return;
+
+	cpu = smp_processor_id();
+	delta = sched_clock_cpu(cpu) - irqtime->irq_start_time;
+	irqtime->irq_start_time += delta;
+	pc = irq_count() - offset;
+
+	/*
+	 * We do not account for softirq time from ksoftirqd here.
+	 * We want to continue accounting softirq time to ksoftirqd thread
+	 * in that case, so as not to confuse scheduler with a special task
+	 * that do not consume any time, but still wants to run.
+	 */
+	if (pc & HARDIRQ_MASK)
+		irqtime_account_delta(irqtime, delta, CPUTIME_IRQ);
+	else if ((pc & SOFTIRQ_OFFSET) && curr != this_cpu_ksoftirqd())
+		irqtime_account_delta(irqtime, delta, CPUTIME_SOFTIRQ);
+}
+
+static u64 irqtime_tick_accounted(u64 maxtime)
+{
+	struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime);
+	u64 delta;
+
+	delta = min(irqtime->tick_delta, maxtime);
+	irqtime->tick_delta -= delta;
+
+	return delta;
+}
+
+#else /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+#define sched_clock_irqtime	(0)
+
+static u64 irqtime_tick_accounted(u64 dummy)
+{
+	return 0;
+}
+
+#endif /* !CONFIG_IRQ_TIME_ACCOUNTING */
+
+static inline void task_group_account_field(struct task_struct *p, int index,
+					    u64 tmp)
+{
+	/*
+	 * Since all updates are sure to touch the root cgroup, we
+	 * get ourselves ahead and touch it first. If the root cgroup
+	 * is the only cgroup, then nothing else should be necessary.
+	 *
+	 */
+	__this_cpu_add(kernel_cpustat.cpustat[index], tmp);
+
+	cgroup_account_cputime_field(p, index, tmp);
+}
+
+/*
+ * Account user CPU time to a process.
+ * @p: the process that the CPU time gets accounted to
+ * @cputime: the CPU time spent in user space since the last update
+ */
+void account_user_time(struct task_struct *p, u64 cputime)
+{
+	int index;
+
+	/* Add user time to process. */
+	p->utime += cputime;
+	account_group_user_time(p, cputime);
+
+	index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
+
+	/* Add user time to cpustat. */
+	task_group_account_field(p, index, cputime);
+
+	/* Account for user time used */
+	acct_account_cputime(p);
+}
+
+/*
+ * Account guest CPU time to a process.
+ * @p: the process that the CPU time gets accounted to
+ * @cputime: the CPU time spent in virtual machine since the last update
+ */
+void account_guest_time(struct task_struct *p, u64 cputime)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+
+	/* Add guest time to process. */
+	p->utime += cputime;
+	account_group_user_time(p, cputime);
+	p->gtime += cputime;
+
+	/* Add guest time to cpustat. */
+	if (task_nice(p) > 0) {
+		task_group_account_field(p, CPUTIME_NICE, cputime);
+		cpustat[CPUTIME_GUEST_NICE] += cputime;
+	} else {
+		task_group_account_field(p, CPUTIME_USER, cputime);
+		cpustat[CPUTIME_GUEST] += cputime;
+	}
+}
+
+/*
+ * Account system CPU time to a process and desired cpustat field
+ * @p: the process that the CPU time gets accounted to
+ * @cputime: the CPU time spent in kernel space since the last update
+ * @index: pointer to cpustat field that has to be updated
+ */
+void account_system_index_time(struct task_struct *p,
+			       u64 cputime, enum cpu_usage_stat index)
+{
+	/* Add system time to process. */
+	p->stime += cputime;
+	account_group_system_time(p, cputime);
+
+	/* Add system time to cpustat. */
+	task_group_account_field(p, index, cputime);
+
+	/* Account for system time used */
+	acct_account_cputime(p);
+}
+
+/*
+ * Account system CPU time to a process.
+ * @p: the process that the CPU time gets accounted to
+ * @hardirq_offset: the offset to subtract from hardirq_count()
+ * @cputime: the CPU time spent in kernel space since the last update
+ */
+void account_system_time(struct task_struct *p, int hardirq_offset, u64 cputime)
+{
+	int index;
+
+	if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
+		account_guest_time(p, cputime);
+		return;
+	}
+
+	if (hardirq_count() - hardirq_offset)
+		index = CPUTIME_IRQ;
+	else if (in_serving_softirq())
+		index = CPUTIME_SOFTIRQ;
+	else
+		index = CPUTIME_SYSTEM;
+
+	account_system_index_time(p, cputime, index);
+}
+
+/*
+ * Account for involuntary wait time.
+ * @cputime: the CPU time spent in involuntary wait
+ */
+void account_steal_time(u64 cputime)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+
+	cpustat[CPUTIME_STEAL] += cputime;
+}
+
+/*
+ * Account for idle time.
+ * @cputime: the CPU time spent in idle wait
+ */
+void account_idle_time(u64 cputime)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+	struct rq *rq = this_rq();
+
+	if (atomic_read(&rq->nr_iowait) > 0)
+		cpustat[CPUTIME_IOWAIT] += cputime;
+	else
+		cpustat[CPUTIME_IDLE] += cputime;
+}
+
+
+#ifdef CONFIG_SCHED_CORE
+/*
+ * Account for forceidle time due to core scheduling.
+ *
+ * REQUIRES: schedstat is enabled.
+ */
+void __account_forceidle_time(struct task_struct *p, u64 delta)
+{
+	__schedstat_add(p->stats.core_forceidle_sum, delta);
+
+	task_group_account_field(p, CPUTIME_FORCEIDLE, delta);
+}
+#endif
+
+/*
+ * When a guest is interrupted for a longer amount of time, missed clock
+ * ticks are not redelivered later. Due to that, this function may on
+ * occasion account more time than the calling functions think elapsed.
+ */
+static __always_inline u64 steal_account_process_time(u64 maxtime)
+{
+#ifdef CONFIG_PARAVIRT
+	if (static_key_false(&paravirt_steal_enabled)) {
+		u64 steal;
+
+		steal = paravirt_steal_clock(smp_processor_id());
+		steal -= this_rq()->prev_steal_time;
+		steal = min(steal, maxtime);
+		account_steal_time(steal);
+		this_rq()->prev_steal_time += steal;
+
+		return steal;
+	}
+#endif
+	return 0;
+}
+
+/*
+ * Account how much elapsed time was spent in steal, irq, or softirq time.
+ */
+static inline u64 account_other_time(u64 max)
+{
+	u64 accounted;
+
+	lockdep_assert_irqs_disabled();
+
+	accounted = steal_account_process_time(max);
+
+	if (accounted < max)
+		accounted += irqtime_tick_accounted(max - accounted);
+
+	return accounted;
+}
+
+#ifdef CONFIG_64BIT
+static inline u64 read_sum_exec_runtime(struct task_struct *t)
+{
+	return t->se.sum_exec_runtime;
+}
+#else
+static u64 read_sum_exec_runtime(struct task_struct *t)
+{
+	u64 ns;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(t, &rf);
+	ns = t->se.sum_exec_runtime;
+	task_rq_unlock(rq, t, &rf);
+
+	return ns;
+}
+#endif
+
+/*
+ * Accumulate raw cputime values of dead tasks (sig->[us]time) and live
+ * tasks (sum on group iteration) belonging to @tsk's group.
+ */
+void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
+{
+	struct signal_struct *sig = tsk->signal;
+	u64 utime, stime;
+	struct task_struct *t;
+	unsigned int seq, nextseq;
+	unsigned long flags;
+
+	/*
+	 * Update current task runtime to account pending time since last
+	 * scheduler action or thread_group_cputime() call. This thread group
+	 * might have other running tasks on different CPUs, but updating
+	 * their runtime can affect syscall performance, so we skip account
+	 * those pending times and rely only on values updated on tick or
+	 * other scheduler action.
+	 */
+	if (same_thread_group(current, tsk))
+		(void) task_sched_runtime(current);
+
+	rcu_read_lock();
+	/* Attempt a lockless read on the first round. */
+	nextseq = 0;
+	do {
+		seq = nextseq;
+		flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);
+		times->utime = sig->utime;
+		times->stime = sig->stime;
+		times->sum_exec_runtime = sig->sum_sched_runtime;
+
+		for_each_thread(tsk, t) {
+			task_cputime(t, &utime, &stime);
+			times->utime += utime;
+			times->stime += stime;
+			times->sum_exec_runtime += read_sum_exec_runtime(t);
+		}
+		/* If lockless access failed, take the lock. */
+		nextseq = 1;
+	} while (need_seqretry(&sig->stats_lock, seq));
+	done_seqretry_irqrestore(&sig->stats_lock, seq, flags);
+	rcu_read_unlock();
+}
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+/*
+ * Account a tick to a process and cpustat
+ * @p: the process that the CPU time gets accounted to
+ * @user_tick: is the tick from userspace
+ * @rq: the pointer to rq
+ *
+ * Tick demultiplexing follows the order
+ * - pending hardirq update
+ * - pending softirq update
+ * - user_time
+ * - idle_time
+ * - system time
+ *   - check for guest_time
+ *   - else account as system_time
+ *
+ * Check for hardirq is done both for system and user time as there is
+ * no timer going off while we are on hardirq and hence we may never get an
+ * opportunity to update it solely in system time.
+ * p->stime and friends are only updated on system time and not on irq
+ * softirq as those do not count in task exec_runtime any more.
+ */
+static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
+					 int ticks)
+{
+	u64 other, cputime = TICK_NSEC * ticks;
+
+	/*
+	 * When returning from idle, many ticks can get accounted at
+	 * once, including some ticks of steal, irq, and softirq time.
+	 * Subtract those ticks from the amount of time accounted to
+	 * idle, or potentially user or system time. Due to rounding,
+	 * other time can exceed ticks occasionally.
+	 */
+	other = account_other_time(ULONG_MAX);
+	if (other >= cputime)
+		return;
+
+	cputime -= other;
+
+	if (this_cpu_ksoftirqd() == p) {
+		/*
+		 * ksoftirqd time do not get accounted in cpu_softirq_time.
+		 * So, we have to handle it separately here.
+		 * Also, p->stime needs to be updated for ksoftirqd.
+		 */
+		account_system_index_time(p, cputime, CPUTIME_SOFTIRQ);
+	} else if (user_tick) {
+		account_user_time(p, cputime);
+	} else if (p == this_rq()->idle) {
+		account_idle_time(cputime);
+	} else if (p->flags & PF_VCPU) { /* System time or guest time */
+		account_guest_time(p, cputime);
+	} else {
+		account_system_index_time(p, cputime, CPUTIME_SYSTEM);
+	}
+}
+
+static void irqtime_account_idle_ticks(int ticks)
+{
+	irqtime_account_process_tick(current, 0, ticks);
+}
+#else /* CONFIG_IRQ_TIME_ACCOUNTING */
+static inline void irqtime_account_idle_ticks(int ticks) { }
+static inline void irqtime_account_process_tick(struct task_struct *p, int user_tick,
+						int nr_ticks) { }
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+/*
+ * Use precise platform statistics if available:
+ */
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+
+# ifndef __ARCH_HAS_VTIME_TASK_SWITCH
+void vtime_task_switch(struct task_struct *prev)
+{
+	if (is_idle_task(prev))
+		vtime_account_idle(prev);
+	else
+		vtime_account_kernel(prev);
+
+	vtime_flush(prev);
+	arch_vtime_task_switch(prev);
+}
+# endif
+
+void vtime_account_irq(struct task_struct *tsk, unsigned int offset)
+{
+	unsigned int pc = irq_count() - offset;
+
+	if (pc & HARDIRQ_OFFSET) {
+		vtime_account_hardirq(tsk);
+	} else if (pc & SOFTIRQ_OFFSET) {
+		vtime_account_softirq(tsk);
+	} else if (!IS_ENABLED(CONFIG_HAVE_VIRT_CPU_ACCOUNTING_IDLE) &&
+		   is_idle_task(tsk)) {
+		vtime_account_idle(tsk);
+	} else {
+		vtime_account_kernel(tsk);
+	}
+}
+
+void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
+		    u64 *ut, u64 *st)
+{
+	*ut = curr->utime;
+	*st = curr->stime;
+}
+
+void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
+{
+	*ut = p->utime;
+	*st = p->stime;
+}
+EXPORT_SYMBOL_GPL(task_cputime_adjusted);
+
+void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
+{
+	struct task_cputime cputime;
+
+	thread_group_cputime(p, &cputime);
+
+	*ut = cputime.utime;
+	*st = cputime.stime;
+}
+
+#else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE: */
+
+/*
+ * Account a single tick of CPU time.
+ * @p: the process that the CPU time gets accounted to
+ * @user_tick: indicates if the tick is a user or a system tick
+ */
+void account_process_tick(struct task_struct *p, int user_tick)
+{
+	u64 cputime, steal;
+
+	if (vtime_accounting_enabled_this_cpu())
+		return;
+
+	if (sched_clock_irqtime) {
+		irqtime_account_process_tick(p, user_tick, 1);
+		return;
+	}
+
+	cputime = TICK_NSEC;
+	steal = steal_account_process_time(ULONG_MAX);
+
+	if (steal >= cputime)
+		return;
+
+	cputime -= steal;
+
+	if (user_tick)
+		account_user_time(p, cputime);
+	else if ((p != this_rq()->idle) || (irq_count() != HARDIRQ_OFFSET))
+		account_system_time(p, HARDIRQ_OFFSET, cputime);
+	else
+		account_idle_time(cputime);
+}
+
+/*
+ * Account multiple ticks of idle time.
+ * @ticks: number of stolen ticks
+ */
+void account_idle_ticks(unsigned long ticks)
+{
+	u64 cputime, steal;
+
+	if (sched_clock_irqtime) {
+		irqtime_account_idle_ticks(ticks);
+		return;
+	}
+
+	cputime = ticks * TICK_NSEC;
+	steal = steal_account_process_time(ULONG_MAX);
+
+	if (steal >= cputime)
+		return;
+
+	cputime -= steal;
+	account_idle_time(cputime);
+}
+
+/*
+ * Adjust tick based cputime random precision against scheduler runtime
+ * accounting.
+ *
+ * Tick based cputime accounting depend on random scheduling timeslices of a
+ * task to be interrupted or not by the timer.  Depending on these
+ * circumstances, the number of these interrupts may be over or
+ * under-optimistic, matching the real user and system cputime with a variable
+ * precision.
+ *
+ * Fix this by scaling these tick based values against the total runtime
+ * accounted by the CFS scheduler.
+ *
+ * This code provides the following guarantees:
+ *
+ *   stime + utime == rtime
+ *   stime_i+1 >= stime_i, utime_i+1 >= utime_i
+ *
+ * Assuming that rtime_i+1 >= rtime_i.
+ */
+void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
+		    u64 *ut, u64 *st)
+{
+	u64 rtime, stime, utime;
+	unsigned long flags;
+
+	/* Serialize concurrent callers such that we can honour our guarantees */
+	raw_spin_lock_irqsave(&prev->lock, flags);
+	rtime = curr->sum_exec_runtime;
+
+	/*
+	 * This is possible under two circumstances:
+	 *  - rtime isn't monotonic after all (a bug);
+	 *  - we got reordered by the lock.
+	 *
+	 * In both cases this acts as a filter such that the rest of the code
+	 * can assume it is monotonic regardless of anything else.
+	 */
+	if (prev->stime + prev->utime >= rtime)
+		goto out;
+
+	stime = curr->stime;
+	utime = curr->utime;
+
+	/*
+	 * If either stime or utime are 0, assume all runtime is userspace.
+	 * Once a task gets some ticks, the monotonicity code at 'update:'
+	 * will ensure things converge to the observed ratio.
+	 */
+	if (stime == 0) {
+		utime = rtime;
+		goto update;
+	}
+
+	if (utime == 0) {
+		stime = rtime;
+		goto update;
+	}
+
+	stime = mul_u64_u64_div_u64(stime, rtime, stime + utime);
+
+update:
+	/*
+	 * Make sure stime doesn't go backwards; this preserves monotonicity
+	 * for utime because rtime is monotonic.
+	 *
+	 *  utime_i+1 = rtime_i+1 - stime_i
+	 *            = rtime_i+1 - (rtime_i - utime_i)
+	 *            = (rtime_i+1 - rtime_i) + utime_i
+	 *            >= utime_i
+	 */
+	if (stime < prev->stime)
+		stime = prev->stime;
+	utime = rtime - stime;
+
+	/*
+	 * Make sure utime doesn't go backwards; this still preserves
+	 * monotonicity for stime, analogous argument to above.
+	 */
+	if (utime < prev->utime) {
+		utime = prev->utime;
+		stime = rtime - utime;
+	}
+
+	prev->stime = stime;
+	prev->utime = utime;
+out:
+	*ut = prev->utime;
+	*st = prev->stime;
+	raw_spin_unlock_irqrestore(&prev->lock, flags);
+}
+
+void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
+{
+	struct task_cputime cputime = {
+		.sum_exec_runtime = p->se.sum_exec_runtime,
+	};
+
+	if (task_cputime(p, &cputime.utime, &cputime.stime))
+		cputime.sum_exec_runtime = task_sched_runtime(p);
+	cputime_adjust(&cputime, &p->prev_cputime, ut, st);
+}
+EXPORT_SYMBOL_GPL(task_cputime_adjusted);
+
+void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
+{
+	struct task_cputime cputime;
+
+	thread_group_cputime(p, &cputime);
+	cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st);
+}
+#endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+static u64 vtime_delta(struct vtime *vtime)
+{
+	unsigned long long clock;
+
+	clock = sched_clock();
+	if (clock < vtime->starttime)
+		return 0;
+
+	return clock - vtime->starttime;
+}
+
+static u64 get_vtime_delta(struct vtime *vtime)
+{
+	u64 delta = vtime_delta(vtime);
+	u64 other;
+
+	/*
+	 * Unlike tick based timing, vtime based timing never has lost
+	 * ticks, and no need for steal time accounting to make up for
+	 * lost ticks. Vtime accounts a rounded version of actual
+	 * elapsed time. Limit account_other_time to prevent rounding
+	 * errors from causing elapsed vtime to go negative.
+	 */
+	other = account_other_time(delta);
+	WARN_ON_ONCE(vtime->state == VTIME_INACTIVE);
+	vtime->starttime += delta;
+
+	return delta - other;
+}
+
+static void vtime_account_system(struct task_struct *tsk,
+				 struct vtime *vtime)
+{
+	vtime->stime += get_vtime_delta(vtime);
+	if (vtime->stime >= TICK_NSEC) {
+		account_system_time(tsk, irq_count(), vtime->stime);
+		vtime->stime = 0;
+	}
+}
+
+static void vtime_account_guest(struct task_struct *tsk,
+				struct vtime *vtime)
+{
+	vtime->gtime += get_vtime_delta(vtime);
+	if (vtime->gtime >= TICK_NSEC) {
+		account_guest_time(tsk, vtime->gtime);
+		vtime->gtime = 0;
+	}
+}
+
+static void __vtime_account_kernel(struct task_struct *tsk,
+				   struct vtime *vtime)
+{
+	/* We might have scheduled out from guest path */
+	if (vtime->state == VTIME_GUEST)
+		vtime_account_guest(tsk, vtime);
+	else
+		vtime_account_system(tsk, vtime);
+}
+
+void vtime_account_kernel(struct task_struct *tsk)
+{
+	struct vtime *vtime = &tsk->vtime;
+
+	if (!vtime_delta(vtime))
+		return;
+
+	write_seqcount_begin(&vtime->seqcount);
+	__vtime_account_kernel(tsk, vtime);
+	write_seqcount_end(&vtime->seqcount);
+}
+
+void vtime_user_enter(struct task_struct *tsk)
+{
+	struct vtime *vtime = &tsk->vtime;
+
+	write_seqcount_begin(&vtime->seqcount);
+	vtime_account_system(tsk, vtime);
+	vtime->state = VTIME_USER;
+	write_seqcount_end(&vtime->seqcount);
+}
+
+void vtime_user_exit(struct task_struct *tsk)
+{
+	struct vtime *vtime = &tsk->vtime;
+
+	write_seqcount_begin(&vtime->seqcount);
+	vtime->utime += get_vtime_delta(vtime);
+	if (vtime->utime >= TICK_NSEC) {
+		account_user_time(tsk, vtime->utime);
+		vtime->utime = 0;
+	}
+	vtime->state = VTIME_SYS;
+	write_seqcount_end(&vtime->seqcount);
+}
+
+void vtime_guest_enter(struct task_struct *tsk)
+{
+	struct vtime *vtime = &tsk->vtime;
+	/*
+	 * The flags must be updated under the lock with
+	 * the vtime_starttime flush and update.
+	 * That enforces a right ordering and update sequence
+	 * synchronization against the reader (task_gtime())
+	 * that can thus safely catch up with a tickless delta.
+	 */
+	write_seqcount_begin(&vtime->seqcount);
+	vtime_account_system(tsk, vtime);
+	tsk->flags |= PF_VCPU;
+	vtime->state = VTIME_GUEST;
+	write_seqcount_end(&vtime->seqcount);
+}
+EXPORT_SYMBOL_GPL(vtime_guest_enter);
+
+void vtime_guest_exit(struct task_struct *tsk)
+{
+	struct vtime *vtime = &tsk->vtime;
+
+	write_seqcount_begin(&vtime->seqcount);
+	vtime_account_guest(tsk, vtime);
+	tsk->flags &= ~PF_VCPU;
+	vtime->state = VTIME_SYS;
+	write_seqcount_end(&vtime->seqcount);
+}
+EXPORT_SYMBOL_GPL(vtime_guest_exit);
+
+void vtime_account_idle(struct task_struct *tsk)
+{
+	account_idle_time(get_vtime_delta(&tsk->vtime));
+}
+
+void vtime_task_switch_generic(struct task_struct *prev)
+{
+	struct vtime *vtime = &prev->vtime;
+
+	write_seqcount_begin(&vtime->seqcount);
+	if (vtime->state == VTIME_IDLE)
+		vtime_account_idle(prev);
+	else
+		__vtime_account_kernel(prev, vtime);
+	vtime->state = VTIME_INACTIVE;
+	vtime->cpu = -1;
+	write_seqcount_end(&vtime->seqcount);
+
+	vtime = &current->vtime;
+
+	write_seqcount_begin(&vtime->seqcount);
+	if (is_idle_task(current))
+		vtime->state = VTIME_IDLE;
+	else if (current->flags & PF_VCPU)
+		vtime->state = VTIME_GUEST;
+	else
+		vtime->state = VTIME_SYS;
+	vtime->starttime = sched_clock();
+	vtime->cpu = smp_processor_id();
+	write_seqcount_end(&vtime->seqcount);
+}
+
+void vtime_init_idle(struct task_struct *t, int cpu)
+{
+	struct vtime *vtime = &t->vtime;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	write_seqcount_begin(&vtime->seqcount);
+	vtime->state = VTIME_IDLE;
+	vtime->starttime = sched_clock();
+	vtime->cpu = cpu;
+	write_seqcount_end(&vtime->seqcount);
+	local_irq_restore(flags);
+}
+
+u64 task_gtime(struct task_struct *t)
+{
+	struct vtime *vtime = &t->vtime;
+	unsigned int seq;
+	u64 gtime;
+
+	if (!vtime_accounting_enabled())
+		return t->gtime;
+
+	do {
+		seq = read_seqcount_begin(&vtime->seqcount);
+
+		gtime = t->gtime;
+		if (vtime->state == VTIME_GUEST)
+			gtime += vtime->gtime + vtime_delta(vtime);
+
+	} while (read_seqcount_retry(&vtime->seqcount, seq));
+
+	return gtime;
+}
+
+/*
+ * Fetch cputime raw values from fields of task_struct and
+ * add up the pending nohz execution time since the last
+ * cputime snapshot.
+ */
+bool task_cputime(struct task_struct *t, u64 *utime, u64 *stime)
+{
+	struct vtime *vtime = &t->vtime;
+	unsigned int seq;
+	u64 delta;
+	int ret;
+
+	if (!vtime_accounting_enabled()) {
+		*utime = t->utime;
+		*stime = t->stime;
+		return false;
+	}
+
+	do {
+		ret = false;
+		seq = read_seqcount_begin(&vtime->seqcount);
+
+		*utime = t->utime;
+		*stime = t->stime;
+
+		/* Task is sleeping or idle, nothing to add */
+		if (vtime->state < VTIME_SYS)
+			continue;
+
+		ret = true;
+		delta = vtime_delta(vtime);
+
+		/*
+		 * Task runs either in user (including guest) or kernel space,
+		 * add pending nohz time to the right place.
+		 */
+		if (vtime->state == VTIME_SYS)
+			*stime += vtime->stime + delta;
+		else
+			*utime += vtime->utime + delta;
+	} while (read_seqcount_retry(&vtime->seqcount, seq));
+
+	return ret;
+}
+
+static int vtime_state_fetch(struct vtime *vtime, int cpu)
+{
+	int state = READ_ONCE(vtime->state);
+
+	/*
+	 * We raced against a context switch, fetch the
+	 * kcpustat task again.
+	 */
+	if (vtime->cpu != cpu && vtime->cpu != -1)
+		return -EAGAIN;
+
+	/*
+	 * Two possible things here:
+	 * 1) We are seeing the scheduling out task (prev) or any past one.
+	 * 2) We are seeing the scheduling in task (next) but it hasn't
+	 *    passed though vtime_task_switch() yet so the pending
+	 *    cputime of the prev task may not be flushed yet.
+	 *
+	 * Case 1) is ok but 2) is not. So wait for a safe VTIME state.
+	 */
+	if (state == VTIME_INACTIVE)
+		return -EAGAIN;
+
+	return state;
+}
+
+static u64 kcpustat_user_vtime(struct vtime *vtime)
+{
+	if (vtime->state == VTIME_USER)
+		return vtime->utime + vtime_delta(vtime);
+	else if (vtime->state == VTIME_GUEST)
+		return vtime->gtime + vtime_delta(vtime);
+	return 0;
+}
+
+static int kcpustat_field_vtime(u64 *cpustat,
+				struct task_struct *tsk,
+				enum cpu_usage_stat usage,
+				int cpu, u64 *val)
+{
+	struct vtime *vtime = &tsk->vtime;
+	unsigned int seq;
+
+	do {
+		int state;
+
+		seq = read_seqcount_begin(&vtime->seqcount);
+
+		state = vtime_state_fetch(vtime, cpu);
+		if (state < 0)
+			return state;
+
+		*val = cpustat[usage];
+
+		/*
+		 * Nice VS unnice cputime accounting may be inaccurate if
+		 * the nice value has changed since the last vtime update.
+		 * But proper fix would involve interrupting target on nice
+		 * updates which is a no go on nohz_full (although the scheduler
+		 * may still interrupt the target if rescheduling is needed...)
+		 */
+		switch (usage) {
+		case CPUTIME_SYSTEM:
+			if (state == VTIME_SYS)
+				*val += vtime->stime + vtime_delta(vtime);
+			break;
+		case CPUTIME_USER:
+			if (task_nice(tsk) <= 0)
+				*val += kcpustat_user_vtime(vtime);
+			break;
+		case CPUTIME_NICE:
+			if (task_nice(tsk) > 0)
+				*val += kcpustat_user_vtime(vtime);
+			break;
+		case CPUTIME_GUEST:
+			if (state == VTIME_GUEST && task_nice(tsk) <= 0)
+				*val += vtime->gtime + vtime_delta(vtime);
+			break;
+		case CPUTIME_GUEST_NICE:
+			if (state == VTIME_GUEST && task_nice(tsk) > 0)
+				*val += vtime->gtime + vtime_delta(vtime);
+			break;
+		default:
+			break;
+		}
+	} while (read_seqcount_retry(&vtime->seqcount, seq));
+
+	return 0;
+}
+
+u64 kcpustat_field(struct kernel_cpustat *kcpustat,
+		   enum cpu_usage_stat usage, int cpu)
+{
+	u64 *cpustat = kcpustat->cpustat;
+	u64 val = cpustat[usage];
+	struct rq *rq;
+	int err;
+
+	if (!vtime_accounting_enabled_cpu(cpu))
+		return val;
+
+	rq = cpu_rq(cpu);
+
+	for (;;) {
+		struct task_struct *curr;
+
+		rcu_read_lock();
+		curr = rcu_dereference(rq->curr);
+		if (WARN_ON_ONCE(!curr)) {
+			rcu_read_unlock();
+			return cpustat[usage];
+		}
+
+		err = kcpustat_field_vtime(cpustat, curr, usage, cpu, &val);
+		rcu_read_unlock();
+
+		if (!err)
+			return val;
+
+		cpu_relax();
+	}
+}
+EXPORT_SYMBOL_GPL(kcpustat_field);
+
+static int kcpustat_cpu_fetch_vtime(struct kernel_cpustat *dst,
+				    const struct kernel_cpustat *src,
+				    struct task_struct *tsk, int cpu)
+{
+	struct vtime *vtime = &tsk->vtime;
+	unsigned int seq;
+
+	do {
+		u64 *cpustat;
+		u64 delta;
+		int state;
+
+		seq = read_seqcount_begin(&vtime->seqcount);
+
+		state = vtime_state_fetch(vtime, cpu);
+		if (state < 0)
+			return state;
+
+		*dst = *src;
+		cpustat = dst->cpustat;
+
+		/* Task is sleeping, dead or idle, nothing to add */
+		if (state < VTIME_SYS)
+			continue;
+
+		delta = vtime_delta(vtime);
+
+		/*
+		 * Task runs either in user (including guest) or kernel space,
+		 * add pending nohz time to the right place.
+		 */
+		if (state == VTIME_SYS) {
+			cpustat[CPUTIME_SYSTEM] += vtime->stime + delta;
+		} else if (state == VTIME_USER) {
+			if (task_nice(tsk) > 0)
+				cpustat[CPUTIME_NICE] += vtime->utime + delta;
+			else
+				cpustat[CPUTIME_USER] += vtime->utime + delta;
+		} else {
+			WARN_ON_ONCE(state != VTIME_GUEST);
+			if (task_nice(tsk) > 0) {
+				cpustat[CPUTIME_GUEST_NICE] += vtime->gtime + delta;
+				cpustat[CPUTIME_NICE] += vtime->gtime + delta;
+			} else {
+				cpustat[CPUTIME_GUEST] += vtime->gtime + delta;
+				cpustat[CPUTIME_USER] += vtime->gtime + delta;
+			}
+		}
+	} while (read_seqcount_retry(&vtime->seqcount, seq));
+
+	return 0;
+}
+
+void kcpustat_cpu_fetch(struct kernel_cpustat *dst, int cpu)
+{
+	const struct kernel_cpustat *src = &kcpustat_cpu(cpu);
+	struct rq *rq;
+	int err;
+
+	if (!vtime_accounting_enabled_cpu(cpu)) {
+		*dst = *src;
+		return;
+	}
+
+	rq = cpu_rq(cpu);
+
+	for (;;) {
+		struct task_struct *curr;
+
+		rcu_read_lock();
+		curr = rcu_dereference(rq->curr);
+		if (WARN_ON_ONCE(!curr)) {
+			rcu_read_unlock();
+			*dst = *src;
+			return;
+		}
+
+		err = kcpustat_cpu_fetch_vtime(dst, src, curr, cpu);
+		rcu_read_unlock();
+
+		if (!err)
+			return;
+
+		cpu_relax();
+	}
+}
+EXPORT_SYMBOL_GPL(kcpustat_cpu_fetch);
+
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
new file mode 100644
index 000000000..389290e95
--- /dev/null
+++ b/kernel/sched/deadline.c
@@ -0,0 +1,3103 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Deadline Scheduling Class (SCHED_DEADLINE)
+ *
+ * Earliest Deadline First (EDF) + Constant Bandwidth Server (CBS).
+ *
+ * Tasks that periodically executes their instances for less than their
+ * runtime won't miss any of their deadlines.
+ * Tasks that are not periodic or sporadic or that tries to execute more
+ * than their reserved bandwidth will be slowed down (and may potentially
+ * miss some of their deadlines), and won't affect any other task.
+ *
+ * Copyright (C) 2012 Dario Faggioli <raistlin@linux.it>,
+ *                    Juri Lelli <juri.lelli@gmail.com>,
+ *                    Michael Trimarchi <michael@amarulasolutions.com>,
+ *                    Fabio Checconi <fchecconi@gmail.com>
+ */
+
+#include <linux/cpuset.h>
+
+/*
+ * Default limits for DL period; on the top end we guard against small util
+ * tasks still getting ridiculously long effective runtimes, on the bottom end we
+ * guard against timer DoS.
+ */
+static unsigned int sysctl_sched_dl_period_max = 1 << 22; /* ~4 seconds */
+static unsigned int sysctl_sched_dl_period_min = 100;     /* 100 us */
+#ifdef CONFIG_SYSCTL
+static struct ctl_table sched_dl_sysctls[] = {
+	{
+		.procname       = "sched_deadline_period_max_us",
+		.data           = &sysctl_sched_dl_period_max,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_douintvec_minmax,
+		.extra1         = (void *)&sysctl_sched_dl_period_min,
+	},
+	{
+		.procname       = "sched_deadline_period_min_us",
+		.data           = &sysctl_sched_dl_period_min,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_douintvec_minmax,
+		.extra2         = (void *)&sysctl_sched_dl_period_max,
+	},
+	{}
+};
+
+static int __init sched_dl_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_dl_sysctls);
+	return 0;
+}
+late_initcall(sched_dl_sysctl_init);
+#endif
+
+static inline struct task_struct *dl_task_of(struct sched_dl_entity *dl_se)
+{
+	return container_of(dl_se, struct task_struct, dl);
+}
+
+static inline struct rq *rq_of_dl_rq(struct dl_rq *dl_rq)
+{
+	return container_of(dl_rq, struct rq, dl);
+}
+
+static inline struct dl_rq *dl_rq_of_se(struct sched_dl_entity *dl_se)
+{
+	struct task_struct *p = dl_task_of(dl_se);
+	struct rq *rq = task_rq(p);
+
+	return &rq->dl;
+}
+
+static inline int on_dl_rq(struct sched_dl_entity *dl_se)
+{
+	return !RB_EMPTY_NODE(&dl_se->rb_node);
+}
+
+#ifdef CONFIG_RT_MUTEXES
+static inline struct sched_dl_entity *pi_of(struct sched_dl_entity *dl_se)
+{
+	return dl_se->pi_se;
+}
+
+static inline bool is_dl_boosted(struct sched_dl_entity *dl_se)
+{
+	return pi_of(dl_se) != dl_se;
+}
+#else
+static inline struct sched_dl_entity *pi_of(struct sched_dl_entity *dl_se)
+{
+	return dl_se;
+}
+
+static inline bool is_dl_boosted(struct sched_dl_entity *dl_se)
+{
+	return false;
+}
+#endif
+
+#ifdef CONFIG_SMP
+static inline struct dl_bw *dl_bw_of(int i)
+{
+	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
+			 "sched RCU must be held");
+	return &cpu_rq(i)->rd->dl_bw;
+}
+
+static inline int dl_bw_cpus(int i)
+{
+	struct root_domain *rd = cpu_rq(i)->rd;
+	int cpus;
+
+	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
+			 "sched RCU must be held");
+
+	if (cpumask_subset(rd->span, cpu_active_mask))
+		return cpumask_weight(rd->span);
+
+	cpus = 0;
+
+	for_each_cpu_and(i, rd->span, cpu_active_mask)
+		cpus++;
+
+	return cpus;
+}
+
+static inline unsigned long __dl_bw_capacity(const struct cpumask *mask)
+{
+	unsigned long cap = 0;
+	int i;
+
+	for_each_cpu_and(i, mask, cpu_active_mask)
+		cap += capacity_orig_of(i);
+
+	return cap;
+}
+
+/*
+ * XXX Fix: If 'rq->rd == def_root_domain' perform AC against capacity
+ * of the CPU the task is running on rather rd's \Sum CPU capacity.
+ */
+static inline unsigned long dl_bw_capacity(int i)
+{
+	if (!sched_asym_cpucap_active() &&
+	    capacity_orig_of(i) == SCHED_CAPACITY_SCALE) {
+		return dl_bw_cpus(i) << SCHED_CAPACITY_SHIFT;
+	} else {
+		RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
+				 "sched RCU must be held");
+
+		return __dl_bw_capacity(cpu_rq(i)->rd->span);
+	}
+}
+
+static inline bool dl_bw_visited(int cpu, u64 gen)
+{
+	struct root_domain *rd = cpu_rq(cpu)->rd;
+
+	if (rd->visit_gen == gen)
+		return true;
+
+	rd->visit_gen = gen;
+	return false;
+}
+
+static inline
+void __dl_update(struct dl_bw *dl_b, s64 bw)
+{
+	struct root_domain *rd = container_of(dl_b, struct root_domain, dl_bw);
+	int i;
+
+	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
+			 "sched RCU must be held");
+	for_each_cpu_and(i, rd->span, cpu_active_mask) {
+		struct rq *rq = cpu_rq(i);
+
+		rq->dl.extra_bw += bw;
+	}
+}
+#else
+static inline struct dl_bw *dl_bw_of(int i)
+{
+	return &cpu_rq(i)->dl.dl_bw;
+}
+
+static inline int dl_bw_cpus(int i)
+{
+	return 1;
+}
+
+static inline unsigned long dl_bw_capacity(int i)
+{
+	return SCHED_CAPACITY_SCALE;
+}
+
+static inline bool dl_bw_visited(int cpu, u64 gen)
+{
+	return false;
+}
+
+static inline
+void __dl_update(struct dl_bw *dl_b, s64 bw)
+{
+	struct dl_rq *dl = container_of(dl_b, struct dl_rq, dl_bw);
+
+	dl->extra_bw += bw;
+}
+#endif
+
+static inline
+void __dl_sub(struct dl_bw *dl_b, u64 tsk_bw, int cpus)
+{
+	dl_b->total_bw -= tsk_bw;
+	__dl_update(dl_b, (s32)tsk_bw / cpus);
+}
+
+static inline
+void __dl_add(struct dl_bw *dl_b, u64 tsk_bw, int cpus)
+{
+	dl_b->total_bw += tsk_bw;
+	__dl_update(dl_b, -((s32)tsk_bw / cpus));
+}
+
+static inline bool
+__dl_overflow(struct dl_bw *dl_b, unsigned long cap, u64 old_bw, u64 new_bw)
+{
+	return dl_b->bw != -1 &&
+	       cap_scale(dl_b->bw, cap) < dl_b->total_bw - old_bw + new_bw;
+}
+
+static inline
+void __add_running_bw(u64 dl_bw, struct dl_rq *dl_rq)
+{
+	u64 old = dl_rq->running_bw;
+
+	lockdep_assert_rq_held(rq_of_dl_rq(dl_rq));
+	dl_rq->running_bw += dl_bw;
+	SCHED_WARN_ON(dl_rq->running_bw < old); /* overflow */
+	SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw);
+	/* kick cpufreq (see the comment in kernel/sched/sched.h). */
+	cpufreq_update_util(rq_of_dl_rq(dl_rq), 0);
+}
+
+static inline
+void __sub_running_bw(u64 dl_bw, struct dl_rq *dl_rq)
+{
+	u64 old = dl_rq->running_bw;
+
+	lockdep_assert_rq_held(rq_of_dl_rq(dl_rq));
+	dl_rq->running_bw -= dl_bw;
+	SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */
+	if (dl_rq->running_bw > old)
+		dl_rq->running_bw = 0;
+	/* kick cpufreq (see the comment in kernel/sched/sched.h). */
+	cpufreq_update_util(rq_of_dl_rq(dl_rq), 0);
+}
+
+static inline
+void __add_rq_bw(u64 dl_bw, struct dl_rq *dl_rq)
+{
+	u64 old = dl_rq->this_bw;
+
+	lockdep_assert_rq_held(rq_of_dl_rq(dl_rq));
+	dl_rq->this_bw += dl_bw;
+	SCHED_WARN_ON(dl_rq->this_bw < old); /* overflow */
+}
+
+static inline
+void __sub_rq_bw(u64 dl_bw, struct dl_rq *dl_rq)
+{
+	u64 old = dl_rq->this_bw;
+
+	lockdep_assert_rq_held(rq_of_dl_rq(dl_rq));
+	dl_rq->this_bw -= dl_bw;
+	SCHED_WARN_ON(dl_rq->this_bw > old); /* underflow */
+	if (dl_rq->this_bw > old)
+		dl_rq->this_bw = 0;
+	SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw);
+}
+
+static inline
+void add_rq_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	if (!dl_entity_is_special(dl_se))
+		__add_rq_bw(dl_se->dl_bw, dl_rq);
+}
+
+static inline
+void sub_rq_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	if (!dl_entity_is_special(dl_se))
+		__sub_rq_bw(dl_se->dl_bw, dl_rq);
+}
+
+static inline
+void add_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	if (!dl_entity_is_special(dl_se))
+		__add_running_bw(dl_se->dl_bw, dl_rq);
+}
+
+static inline
+void sub_running_bw(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	if (!dl_entity_is_special(dl_se))
+		__sub_running_bw(dl_se->dl_bw, dl_rq);
+}
+
+static void dl_change_utilization(struct task_struct *p, u64 new_bw)
+{
+	struct rq *rq;
+
+	WARN_ON_ONCE(p->dl.flags & SCHED_FLAG_SUGOV);
+
+	if (task_on_rq_queued(p))
+		return;
+
+	rq = task_rq(p);
+	if (p->dl.dl_non_contending) {
+		sub_running_bw(&p->dl, &rq->dl);
+		p->dl.dl_non_contending = 0;
+		/*
+		 * If the timer handler is currently running and the
+		 * timer cannot be canceled, inactive_task_timer()
+		 * will see that dl_not_contending is not set, and
+		 * will not touch the rq's active utilization,
+		 * so we are still safe.
+		 */
+		if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1)
+			put_task_struct(p);
+	}
+	__sub_rq_bw(p->dl.dl_bw, &rq->dl);
+	__add_rq_bw(new_bw, &rq->dl);
+}
+
+/*
+ * The utilization of a task cannot be immediately removed from
+ * the rq active utilization (running_bw) when the task blocks.
+ * Instead, we have to wait for the so called "0-lag time".
+ *
+ * If a task blocks before the "0-lag time", a timer (the inactive
+ * timer) is armed, and running_bw is decreased when the timer
+ * fires.
+ *
+ * If the task wakes up again before the inactive timer fires,
+ * the timer is canceled, whereas if the task wakes up after the
+ * inactive timer fired (and running_bw has been decreased) the
+ * task's utilization has to be added to running_bw again.
+ * A flag in the deadline scheduling entity (dl_non_contending)
+ * is used to avoid race conditions between the inactive timer handler
+ * and task wakeups.
+ *
+ * The following diagram shows how running_bw is updated. A task is
+ * "ACTIVE" when its utilization contributes to running_bw; an
+ * "ACTIVE contending" task is in the TASK_RUNNING state, while an
+ * "ACTIVE non contending" task is a blocked task for which the "0-lag time"
+ * has not passed yet. An "INACTIVE" task is a task for which the "0-lag"
+ * time already passed, which does not contribute to running_bw anymore.
+ *                              +------------------+
+ *             wakeup           |    ACTIVE        |
+ *          +------------------>+   contending     |
+ *          | add_running_bw    |                  |
+ *          |                   +----+------+------+
+ *          |                        |      ^
+ *          |                dequeue |      |
+ * +--------+-------+                |      |
+ * |                |   t >= 0-lag   |      | wakeup
+ * |    INACTIVE    |<---------------+      |
+ * |                | sub_running_bw |      |
+ * +--------+-------+                |      |
+ *          ^                        |      |
+ *          |              t < 0-lag |      |
+ *          |                        |      |
+ *          |                        V      |
+ *          |                   +----+------+------+
+ *          | sub_running_bw    |    ACTIVE        |
+ *          +-------------------+                  |
+ *            inactive timer    |  non contending  |
+ *            fired             +------------------+
+ *
+ * The task_non_contending() function is invoked when a task
+ * blocks, and checks if the 0-lag time already passed or
+ * not (in the first case, it directly updates running_bw;
+ * in the second case, it arms the inactive timer).
+ *
+ * The task_contending() function is invoked when a task wakes
+ * up, and checks if the task is still in the "ACTIVE non contending"
+ * state or not (in the second case, it updates running_bw).
+ */
+static void task_non_contending(struct task_struct *p)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+	struct hrtimer *timer = &dl_se->inactive_timer;
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+	s64 zerolag_time;
+
+	/*
+	 * If this is a non-deadline task that has been boosted,
+	 * do nothing
+	 */
+	if (dl_se->dl_runtime == 0)
+		return;
+
+	if (dl_entity_is_special(dl_se))
+		return;
+
+	WARN_ON(dl_se->dl_non_contending);
+
+	zerolag_time = dl_se->deadline -
+		 div64_long((dl_se->runtime * dl_se->dl_period),
+			dl_se->dl_runtime);
+
+	/*
+	 * Using relative times instead of the absolute "0-lag time"
+	 * allows to simplify the code
+	 */
+	zerolag_time -= rq_clock(rq);
+
+	/*
+	 * If the "0-lag time" already passed, decrease the active
+	 * utilization now, instead of starting a timer
+	 */
+	if ((zerolag_time < 0) || hrtimer_active(&dl_se->inactive_timer)) {
+		if (dl_task(p))
+			sub_running_bw(dl_se, dl_rq);
+		if (!dl_task(p) || READ_ONCE(p->__state) == TASK_DEAD) {
+			struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
+
+			if (READ_ONCE(p->__state) == TASK_DEAD)
+				sub_rq_bw(&p->dl, &rq->dl);
+			raw_spin_lock(&dl_b->lock);
+			__dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p)));
+			raw_spin_unlock(&dl_b->lock);
+			__dl_clear_params(p);
+		}
+
+		return;
+	}
+
+	dl_se->dl_non_contending = 1;
+	get_task_struct(p);
+	hrtimer_start(timer, ns_to_ktime(zerolag_time), HRTIMER_MODE_REL_HARD);
+}
+
+static void task_contending(struct sched_dl_entity *dl_se, int flags)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+
+	/*
+	 * If this is a non-deadline task that has been boosted,
+	 * do nothing
+	 */
+	if (dl_se->dl_runtime == 0)
+		return;
+
+	if (flags & ENQUEUE_MIGRATED)
+		add_rq_bw(dl_se, dl_rq);
+
+	if (dl_se->dl_non_contending) {
+		dl_se->dl_non_contending = 0;
+		/*
+		 * If the timer handler is currently running and the
+		 * timer cannot be canceled, inactive_task_timer()
+		 * will see that dl_not_contending is not set, and
+		 * will not touch the rq's active utilization,
+		 * so we are still safe.
+		 */
+		if (hrtimer_try_to_cancel(&dl_se->inactive_timer) == 1)
+			put_task_struct(dl_task_of(dl_se));
+	} else {
+		/*
+		 * Since "dl_non_contending" is not set, the
+		 * task's utilization has already been removed from
+		 * active utilization (either when the task blocked,
+		 * when the "inactive timer" fired).
+		 * So, add it back.
+		 */
+		add_running_bw(dl_se, dl_rq);
+	}
+}
+
+static inline int is_leftmost(struct task_struct *p, struct dl_rq *dl_rq)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+
+	return rb_first_cached(&dl_rq->root) == &dl_se->rb_node;
+}
+
+static void init_dl_rq_bw_ratio(struct dl_rq *dl_rq);
+
+void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime)
+{
+	raw_spin_lock_init(&dl_b->dl_runtime_lock);
+	dl_b->dl_period = period;
+	dl_b->dl_runtime = runtime;
+}
+
+void init_dl_bw(struct dl_bw *dl_b)
+{
+	raw_spin_lock_init(&dl_b->lock);
+	if (global_rt_runtime() == RUNTIME_INF)
+		dl_b->bw = -1;
+	else
+		dl_b->bw = to_ratio(global_rt_period(), global_rt_runtime());
+	dl_b->total_bw = 0;
+}
+
+void init_dl_rq(struct dl_rq *dl_rq)
+{
+	dl_rq->root = RB_ROOT_CACHED;
+
+#ifdef CONFIG_SMP
+	/* zero means no -deadline tasks */
+	dl_rq->earliest_dl.curr = dl_rq->earliest_dl.next = 0;
+
+	dl_rq->dl_nr_migratory = 0;
+	dl_rq->overloaded = 0;
+	dl_rq->pushable_dl_tasks_root = RB_ROOT_CACHED;
+#else
+	init_dl_bw(&dl_rq->dl_bw);
+#endif
+
+	dl_rq->running_bw = 0;
+	dl_rq->this_bw = 0;
+	init_dl_rq_bw_ratio(dl_rq);
+}
+
+#ifdef CONFIG_SMP
+
+static inline int dl_overloaded(struct rq *rq)
+{
+	return atomic_read(&rq->rd->dlo_count);
+}
+
+static inline void dl_set_overload(struct rq *rq)
+{
+	if (!rq->online)
+		return;
+
+	cpumask_set_cpu(rq->cpu, rq->rd->dlo_mask);
+	/*
+	 * Must be visible before the overload count is
+	 * set (as in sched_rt.c).
+	 *
+	 * Matched by the barrier in pull_dl_task().
+	 */
+	smp_wmb();
+	atomic_inc(&rq->rd->dlo_count);
+}
+
+static inline void dl_clear_overload(struct rq *rq)
+{
+	if (!rq->online)
+		return;
+
+	atomic_dec(&rq->rd->dlo_count);
+	cpumask_clear_cpu(rq->cpu, rq->rd->dlo_mask);
+}
+
+static void update_dl_migration(struct dl_rq *dl_rq)
+{
+	if (dl_rq->dl_nr_migratory && dl_rq->dl_nr_running > 1) {
+		if (!dl_rq->overloaded) {
+			dl_set_overload(rq_of_dl_rq(dl_rq));
+			dl_rq->overloaded = 1;
+		}
+	} else if (dl_rq->overloaded) {
+		dl_clear_overload(rq_of_dl_rq(dl_rq));
+		dl_rq->overloaded = 0;
+	}
+}
+
+static void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	struct task_struct *p = dl_task_of(dl_se);
+
+	if (p->nr_cpus_allowed > 1)
+		dl_rq->dl_nr_migratory++;
+
+	update_dl_migration(dl_rq);
+}
+
+static void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	struct task_struct *p = dl_task_of(dl_se);
+
+	if (p->nr_cpus_allowed > 1)
+		dl_rq->dl_nr_migratory--;
+
+	update_dl_migration(dl_rq);
+}
+
+#define __node_2_pdl(node) \
+	rb_entry((node), struct task_struct, pushable_dl_tasks)
+
+static inline bool __pushable_less(struct rb_node *a, const struct rb_node *b)
+{
+	return dl_entity_preempt(&__node_2_pdl(a)->dl, &__node_2_pdl(b)->dl);
+}
+
+/*
+ * The list of pushable -deadline task is not a plist, like in
+ * sched_rt.c, it is an rb-tree with tasks ordered by deadline.
+ */
+static void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p)
+{
+	struct rb_node *leftmost;
+
+	WARN_ON_ONCE(!RB_EMPTY_NODE(&p->pushable_dl_tasks));
+
+	leftmost = rb_add_cached(&p->pushable_dl_tasks,
+				 &rq->dl.pushable_dl_tasks_root,
+				 __pushable_less);
+	if (leftmost)
+		rq->dl.earliest_dl.next = p->dl.deadline;
+}
+
+static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p)
+{
+	struct dl_rq *dl_rq = &rq->dl;
+	struct rb_root_cached *root = &dl_rq->pushable_dl_tasks_root;
+	struct rb_node *leftmost;
+
+	if (RB_EMPTY_NODE(&p->pushable_dl_tasks))
+		return;
+
+	leftmost = rb_erase_cached(&p->pushable_dl_tasks, root);
+	if (leftmost)
+		dl_rq->earliest_dl.next = __node_2_pdl(leftmost)->dl.deadline;
+
+	RB_CLEAR_NODE(&p->pushable_dl_tasks);
+}
+
+static inline int has_pushable_dl_tasks(struct rq *rq)
+{
+	return !RB_EMPTY_ROOT(&rq->dl.pushable_dl_tasks_root.rb_root);
+}
+
+static int push_dl_task(struct rq *rq);
+
+static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev)
+{
+	return rq->online && dl_task(prev);
+}
+
+static DEFINE_PER_CPU(struct balance_callback, dl_push_head);
+static DEFINE_PER_CPU(struct balance_callback, dl_pull_head);
+
+static void push_dl_tasks(struct rq *);
+static void pull_dl_task(struct rq *);
+
+static inline void deadline_queue_push_tasks(struct rq *rq)
+{
+	if (!has_pushable_dl_tasks(rq))
+		return;
+
+	queue_balance_callback(rq, &per_cpu(dl_push_head, rq->cpu), push_dl_tasks);
+}
+
+static inline void deadline_queue_pull_task(struct rq *rq)
+{
+	queue_balance_callback(rq, &per_cpu(dl_pull_head, rq->cpu), pull_dl_task);
+}
+
+static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq);
+
+static struct rq *dl_task_offline_migration(struct rq *rq, struct task_struct *p)
+{
+	struct rq *later_rq = NULL;
+	struct dl_bw *dl_b;
+
+	later_rq = find_lock_later_rq(p, rq);
+	if (!later_rq) {
+		int cpu;
+
+		/*
+		 * If we cannot preempt any rq, fall back to pick any
+		 * online CPU:
+		 */
+		cpu = cpumask_any_and(cpu_active_mask, p->cpus_ptr);
+		if (cpu >= nr_cpu_ids) {
+			/*
+			 * Failed to find any suitable CPU.
+			 * The task will never come back!
+			 */
+			WARN_ON_ONCE(dl_bandwidth_enabled());
+
+			/*
+			 * If admission control is disabled we
+			 * try a little harder to let the task
+			 * run.
+			 */
+			cpu = cpumask_any(cpu_active_mask);
+		}
+		later_rq = cpu_rq(cpu);
+		double_lock_balance(rq, later_rq);
+	}
+
+	if (p->dl.dl_non_contending || p->dl.dl_throttled) {
+		/*
+		 * Inactive timer is armed (or callback is running, but
+		 * waiting for us to release rq locks). In any case, when it
+		 * will fire (or continue), it will see running_bw of this
+		 * task migrated to later_rq (and correctly handle it).
+		 */
+		sub_running_bw(&p->dl, &rq->dl);
+		sub_rq_bw(&p->dl, &rq->dl);
+
+		add_rq_bw(&p->dl, &later_rq->dl);
+		add_running_bw(&p->dl, &later_rq->dl);
+	} else {
+		sub_rq_bw(&p->dl, &rq->dl);
+		add_rq_bw(&p->dl, &later_rq->dl);
+	}
+
+	/*
+	 * And we finally need to fixup root_domain(s) bandwidth accounting,
+	 * since p is still hanging out in the old (now moved to default) root
+	 * domain.
+	 */
+	dl_b = &rq->rd->dl_bw;
+	raw_spin_lock(&dl_b->lock);
+	__dl_sub(dl_b, p->dl.dl_bw, cpumask_weight(rq->rd->span));
+	raw_spin_unlock(&dl_b->lock);
+
+	dl_b = &later_rq->rd->dl_bw;
+	raw_spin_lock(&dl_b->lock);
+	__dl_add(dl_b, p->dl.dl_bw, cpumask_weight(later_rq->rd->span));
+	raw_spin_unlock(&dl_b->lock);
+
+	set_task_cpu(p, later_rq->cpu);
+	double_unlock_balance(later_rq, rq);
+
+	return later_rq;
+}
+
+#else
+
+static inline
+void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline
+void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline
+void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+}
+
+static inline
+void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+}
+
+static inline void deadline_queue_push_tasks(struct rq *rq)
+{
+}
+
+static inline void deadline_queue_pull_task(struct rq *rq)
+{
+}
+#endif /* CONFIG_SMP */
+
+static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags);
+static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags);
+static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, int flags);
+
+static inline void replenish_dl_new_period(struct sched_dl_entity *dl_se,
+					    struct rq *rq)
+{
+	/* for non-boosted task, pi_of(dl_se) == dl_se */
+	dl_se->deadline = rq_clock(rq) + pi_of(dl_se)->dl_deadline;
+	dl_se->runtime = pi_of(dl_se)->dl_runtime;
+}
+
+/*
+ * We are being explicitly informed that a new instance is starting,
+ * and this means that:
+ *  - the absolute deadline of the entity has to be placed at
+ *    current time + relative deadline;
+ *  - the runtime of the entity has to be set to the maximum value.
+ *
+ * The capability of specifying such event is useful whenever a -deadline
+ * entity wants to (try to!) synchronize its behaviour with the scheduler's
+ * one, and to (try to!) reconcile itself with its own scheduling
+ * parameters.
+ */
+static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+
+	WARN_ON(is_dl_boosted(dl_se));
+	WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline));
+
+	/*
+	 * We are racing with the deadline timer. So, do nothing because
+	 * the deadline timer handler will take care of properly recharging
+	 * the runtime and postponing the deadline
+	 */
+	if (dl_se->dl_throttled)
+		return;
+
+	/*
+	 * We use the regular wall clock time to set deadlines in the
+	 * future; in fact, we must consider execution overheads (time
+	 * spent on hardirq context, etc.).
+	 */
+	replenish_dl_new_period(dl_se, rq);
+}
+
+/*
+ * Pure Earliest Deadline First (EDF) scheduling does not deal with the
+ * possibility of a entity lasting more than what it declared, and thus
+ * exhausting its runtime.
+ *
+ * Here we are interested in making runtime overrun possible, but we do
+ * not want a entity which is misbehaving to affect the scheduling of all
+ * other entities.
+ * Therefore, a budgeting strategy called Constant Bandwidth Server (CBS)
+ * is used, in order to confine each entity within its own bandwidth.
+ *
+ * This function deals exactly with that, and ensures that when the runtime
+ * of a entity is replenished, its deadline is also postponed. That ensures
+ * the overrunning entity can't interfere with other entity in the system and
+ * can't make them miss their deadlines. Reasons why this kind of overruns
+ * could happen are, typically, a entity voluntarily trying to overcome its
+ * runtime, or it just underestimated it during sched_setattr().
+ */
+static void replenish_dl_entity(struct sched_dl_entity *dl_se)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+
+	WARN_ON_ONCE(pi_of(dl_se)->dl_runtime <= 0);
+
+	/*
+	 * This could be the case for a !-dl task that is boosted.
+	 * Just go with full inherited parameters.
+	 */
+	if (dl_se->dl_deadline == 0)
+		replenish_dl_new_period(dl_se, rq);
+
+	if (dl_se->dl_yielded && dl_se->runtime > 0)
+		dl_se->runtime = 0;
+
+	/*
+	 * We keep moving the deadline away until we get some
+	 * available runtime for the entity. This ensures correct
+	 * handling of situations where the runtime overrun is
+	 * arbitrary large.
+	 */
+	while (dl_se->runtime <= 0) {
+		dl_se->deadline += pi_of(dl_se)->dl_period;
+		dl_se->runtime += pi_of(dl_se)->dl_runtime;
+	}
+
+	/*
+	 * At this point, the deadline really should be "in
+	 * the future" with respect to rq->clock. If it's
+	 * not, we are, for some reason, lagging too much!
+	 * Anyway, after having warn userspace abut that,
+	 * we still try to keep the things running by
+	 * resetting the deadline and the budget of the
+	 * entity.
+	 */
+	if (dl_time_before(dl_se->deadline, rq_clock(rq))) {
+		printk_deferred_once("sched: DL replenish lagged too much\n");
+		replenish_dl_new_period(dl_se, rq);
+	}
+
+	if (dl_se->dl_yielded)
+		dl_se->dl_yielded = 0;
+	if (dl_se->dl_throttled)
+		dl_se->dl_throttled = 0;
+}
+
+/*
+ * Here we check if --at time t-- an entity (which is probably being
+ * [re]activated or, in general, enqueued) can use its remaining runtime
+ * and its current deadline _without_ exceeding the bandwidth it is
+ * assigned (function returns true if it can't). We are in fact applying
+ * one of the CBS rules: when a task wakes up, if the residual runtime
+ * over residual deadline fits within the allocated bandwidth, then we
+ * can keep the current (absolute) deadline and residual budget without
+ * disrupting the schedulability of the system. Otherwise, we should
+ * refill the runtime and set the deadline a period in the future,
+ * because keeping the current (absolute) deadline of the task would
+ * result in breaking guarantees promised to other tasks (refer to
+ * Documentation/scheduler/sched-deadline.rst for more information).
+ *
+ * This function returns true if:
+ *
+ *   runtime / (deadline - t) > dl_runtime / dl_deadline ,
+ *
+ * IOW we can't recycle current parameters.
+ *
+ * Notice that the bandwidth check is done against the deadline. For
+ * task with deadline equal to period this is the same of using
+ * dl_period instead of dl_deadline in the equation above.
+ */
+static bool dl_entity_overflow(struct sched_dl_entity *dl_se, u64 t)
+{
+	u64 left, right;
+
+	/*
+	 * left and right are the two sides of the equation above,
+	 * after a bit of shuffling to use multiplications instead
+	 * of divisions.
+	 *
+	 * Note that none of the time values involved in the two
+	 * multiplications are absolute: dl_deadline and dl_runtime
+	 * are the relative deadline and the maximum runtime of each
+	 * instance, runtime is the runtime left for the last instance
+	 * and (deadline - t), since t is rq->clock, is the time left
+	 * to the (absolute) deadline. Even if overflowing the u64 type
+	 * is very unlikely to occur in both cases, here we scale down
+	 * as we want to avoid that risk at all. Scaling down by 10
+	 * means that we reduce granularity to 1us. We are fine with it,
+	 * since this is only a true/false check and, anyway, thinking
+	 * of anything below microseconds resolution is actually fiction
+	 * (but still we want to give the user that illusion >;).
+	 */
+	left = (pi_of(dl_se)->dl_deadline >> DL_SCALE) * (dl_se->runtime >> DL_SCALE);
+	right = ((dl_se->deadline - t) >> DL_SCALE) *
+		(pi_of(dl_se)->dl_runtime >> DL_SCALE);
+
+	return dl_time_before(right, left);
+}
+
+/*
+ * Revised wakeup rule [1]: For self-suspending tasks, rather then
+ * re-initializing task's runtime and deadline, the revised wakeup
+ * rule adjusts the task's runtime to avoid the task to overrun its
+ * density.
+ *
+ * Reasoning: a task may overrun the density if:
+ *    runtime / (deadline - t) > dl_runtime / dl_deadline
+ *
+ * Therefore, runtime can be adjusted to:
+ *     runtime = (dl_runtime / dl_deadline) * (deadline - t)
+ *
+ * In such way that runtime will be equal to the maximum density
+ * the task can use without breaking any rule.
+ *
+ * [1] Luca Abeni, Giuseppe Lipari, and Juri Lelli. 2015. Constant
+ * bandwidth server revisited. SIGBED Rev. 11, 4 (January 2015), 19-24.
+ */
+static void
+update_dl_revised_wakeup(struct sched_dl_entity *dl_se, struct rq *rq)
+{
+	u64 laxity = dl_se->deadline - rq_clock(rq);
+
+	/*
+	 * If the task has deadline < period, and the deadline is in the past,
+	 * it should already be throttled before this check.
+	 *
+	 * See update_dl_entity() comments for further details.
+	 */
+	WARN_ON(dl_time_before(dl_se->deadline, rq_clock(rq)));
+
+	dl_se->runtime = (dl_se->dl_density * laxity) >> BW_SHIFT;
+}
+
+/*
+ * Regarding the deadline, a task with implicit deadline has a relative
+ * deadline == relative period. A task with constrained deadline has a
+ * relative deadline <= relative period.
+ *
+ * We support constrained deadline tasks. However, there are some restrictions
+ * applied only for tasks which do not have an implicit deadline. See
+ * update_dl_entity() to know more about such restrictions.
+ *
+ * The dl_is_implicit() returns true if the task has an implicit deadline.
+ */
+static inline bool dl_is_implicit(struct sched_dl_entity *dl_se)
+{
+	return dl_se->dl_deadline == dl_se->dl_period;
+}
+
+/*
+ * When a deadline entity is placed in the runqueue, its runtime and deadline
+ * might need to be updated. This is done by a CBS wake up rule. There are two
+ * different rules: 1) the original CBS; and 2) the Revisited CBS.
+ *
+ * When the task is starting a new period, the Original CBS is used. In this
+ * case, the runtime is replenished and a new absolute deadline is set.
+ *
+ * When a task is queued before the begin of the next period, using the
+ * remaining runtime and deadline could make the entity to overflow, see
+ * dl_entity_overflow() to find more about runtime overflow. When such case
+ * is detected, the runtime and deadline need to be updated.
+ *
+ * If the task has an implicit deadline, i.e., deadline == period, the Original
+ * CBS is applied. the runtime is replenished and a new absolute deadline is
+ * set, as in the previous cases.
+ *
+ * However, the Original CBS does not work properly for tasks with
+ * deadline < period, which are said to have a constrained deadline. By
+ * applying the Original CBS, a constrained deadline task would be able to run
+ * runtime/deadline in a period. With deadline < period, the task would
+ * overrun the runtime/period allowed bandwidth, breaking the admission test.
+ *
+ * In order to prevent this misbehave, the Revisited CBS is used for
+ * constrained deadline tasks when a runtime overflow is detected. In the
+ * Revisited CBS, rather than replenishing & setting a new absolute deadline,
+ * the remaining runtime of the task is reduced to avoid runtime overflow.
+ * Please refer to the comments update_dl_revised_wakeup() function to find
+ * more about the Revised CBS rule.
+ */
+static void update_dl_entity(struct sched_dl_entity *dl_se)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+
+	if (dl_time_before(dl_se->deadline, rq_clock(rq)) ||
+	    dl_entity_overflow(dl_se, rq_clock(rq))) {
+
+		if (unlikely(!dl_is_implicit(dl_se) &&
+			     !dl_time_before(dl_se->deadline, rq_clock(rq)) &&
+			     !is_dl_boosted(dl_se))) {
+			update_dl_revised_wakeup(dl_se, rq);
+			return;
+		}
+
+		replenish_dl_new_period(dl_se, rq);
+	}
+}
+
+static inline u64 dl_next_period(struct sched_dl_entity *dl_se)
+{
+	return dl_se->deadline - dl_se->dl_deadline + dl_se->dl_period;
+}
+
+/*
+ * If the entity depleted all its runtime, and if we want it to sleep
+ * while waiting for some new execution time to become available, we
+ * set the bandwidth replenishment timer to the replenishment instant
+ * and try to activate it.
+ *
+ * Notice that it is important for the caller to know if the timer
+ * actually started or not (i.e., the replenishment instant is in
+ * the future or in the past).
+ */
+static int start_dl_timer(struct task_struct *p)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+	struct hrtimer *timer = &dl_se->dl_timer;
+	struct rq *rq = task_rq(p);
+	ktime_t now, act;
+	s64 delta;
+
+	lockdep_assert_rq_held(rq);
+
+	/*
+	 * We want the timer to fire at the deadline, but considering
+	 * that it is actually coming from rq->clock and not from
+	 * hrtimer's time base reading.
+	 */
+	act = ns_to_ktime(dl_next_period(dl_se));
+	now = hrtimer_cb_get_time(timer);
+	delta = ktime_to_ns(now) - rq_clock(rq);
+	act = ktime_add_ns(act, delta);
+
+	/*
+	 * If the expiry time already passed, e.g., because the value
+	 * chosen as the deadline is too small, don't even try to
+	 * start the timer in the past!
+	 */
+	if (ktime_us_delta(act, now) < 0)
+		return 0;
+
+	/*
+	 * !enqueued will guarantee another callback; even if one is already in
+	 * progress. This ensures a balanced {get,put}_task_struct().
+	 *
+	 * The race against __run_timer() clearing the enqueued state is
+	 * harmless because we're holding task_rq()->lock, therefore the timer
+	 * expiring after we've done the check will wait on its task_rq_lock()
+	 * and observe our state.
+	 */
+	if (!hrtimer_is_queued(timer)) {
+		get_task_struct(p);
+		hrtimer_start(timer, act, HRTIMER_MODE_ABS_HARD);
+	}
+
+	return 1;
+}
+
+/*
+ * This is the bandwidth enforcement timer callback. If here, we know
+ * a task is not on its dl_rq, since the fact that the timer was running
+ * means the task is throttled and needs a runtime replenishment.
+ *
+ * However, what we actually do depends on the fact the task is active,
+ * (it is on its rq) or has been removed from there by a call to
+ * dequeue_task_dl(). In the former case we must issue the runtime
+ * replenishment and add the task back to the dl_rq; in the latter, we just
+ * do nothing but clearing dl_throttled, so that runtime and deadline
+ * updating (and the queueing back to dl_rq) will be done by the
+ * next call to enqueue_task_dl().
+ */
+static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
+{
+	struct sched_dl_entity *dl_se = container_of(timer,
+						     struct sched_dl_entity,
+						     dl_timer);
+	struct task_struct *p = dl_task_of(dl_se);
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(p, &rf);
+
+	/*
+	 * The task might have changed its scheduling policy to something
+	 * different than SCHED_DEADLINE (through switched_from_dl()).
+	 */
+	if (!dl_task(p))
+		goto unlock;
+
+	/*
+	 * The task might have been boosted by someone else and might be in the
+	 * boosting/deboosting path, its not throttled.
+	 */
+	if (is_dl_boosted(dl_se))
+		goto unlock;
+
+	/*
+	 * Spurious timer due to start_dl_timer() race; or we already received
+	 * a replenishment from rt_mutex_setprio().
+	 */
+	if (!dl_se->dl_throttled)
+		goto unlock;
+
+	sched_clock_tick();
+	update_rq_clock(rq);
+
+	/*
+	 * If the throttle happened during sched-out; like:
+	 *
+	 *   schedule()
+	 *     deactivate_task()
+	 *       dequeue_task_dl()
+	 *         update_curr_dl()
+	 *           start_dl_timer()
+	 *         __dequeue_task_dl()
+	 *     prev->on_rq = 0;
+	 *
+	 * We can be both throttled and !queued. Replenish the counter
+	 * but do not enqueue -- wait for our wakeup to do that.
+	 */
+	if (!task_on_rq_queued(p)) {
+		replenish_dl_entity(dl_se);
+		goto unlock;
+	}
+
+#ifdef CONFIG_SMP
+	if (unlikely(!rq->online)) {
+		/*
+		 * If the runqueue is no longer available, migrate the
+		 * task elsewhere. This necessarily changes rq.
+		 */
+		lockdep_unpin_lock(__rq_lockp(rq), rf.cookie);
+		rq = dl_task_offline_migration(rq, p);
+		rf.cookie = lockdep_pin_lock(__rq_lockp(rq));
+		update_rq_clock(rq);
+
+		/*
+		 * Now that the task has been migrated to the new RQ and we
+		 * have that locked, proceed as normal and enqueue the task
+		 * there.
+		 */
+	}
+#endif
+
+	enqueue_task_dl(rq, p, ENQUEUE_REPLENISH);
+	if (dl_task(rq->curr))
+		check_preempt_curr_dl(rq, p, 0);
+	else
+		resched_curr(rq);
+
+#ifdef CONFIG_SMP
+	/*
+	 * Queueing this task back might have overloaded rq, check if we need
+	 * to kick someone away.
+	 */
+	if (has_pushable_dl_tasks(rq)) {
+		/*
+		 * Nothing relies on rq->lock after this, so its safe to drop
+		 * rq->lock.
+		 */
+		rq_unpin_lock(rq, &rf);
+		push_dl_task(rq);
+		rq_repin_lock(rq, &rf);
+	}
+#endif
+
+unlock:
+	task_rq_unlock(rq, p, &rf);
+
+	/*
+	 * This can free the task_struct, including this hrtimer, do not touch
+	 * anything related to that after this.
+	 */
+	put_task_struct(p);
+
+	return HRTIMER_NORESTART;
+}
+
+void init_dl_task_timer(struct sched_dl_entity *dl_se)
+{
+	struct hrtimer *timer = &dl_se->dl_timer;
+
+	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	timer->function = dl_task_timer;
+}
+
+/*
+ * During the activation, CBS checks if it can reuse the current task's
+ * runtime and period. If the deadline of the task is in the past, CBS
+ * cannot use the runtime, and so it replenishes the task. This rule
+ * works fine for implicit deadline tasks (deadline == period), and the
+ * CBS was designed for implicit deadline tasks. However, a task with
+ * constrained deadline (deadline < period) might be awakened after the
+ * deadline, but before the next period. In this case, replenishing the
+ * task would allow it to run for runtime / deadline. As in this case
+ * deadline < period, CBS enables a task to run for more than the
+ * runtime / period. In a very loaded system, this can cause a domino
+ * effect, making other tasks miss their deadlines.
+ *
+ * To avoid this problem, in the activation of a constrained deadline
+ * task after the deadline but before the next period, throttle the
+ * task and set the replenishing timer to the begin of the next period,
+ * unless it is boosted.
+ */
+static inline void dl_check_constrained_dl(struct sched_dl_entity *dl_se)
+{
+	struct task_struct *p = dl_task_of(dl_se);
+	struct rq *rq = rq_of_dl_rq(dl_rq_of_se(dl_se));
+
+	if (dl_time_before(dl_se->deadline, rq_clock(rq)) &&
+	    dl_time_before(rq_clock(rq), dl_next_period(dl_se))) {
+		if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(p)))
+			return;
+		dl_se->dl_throttled = 1;
+		if (dl_se->runtime > 0)
+			dl_se->runtime = 0;
+	}
+}
+
+static
+int dl_runtime_exceeded(struct sched_dl_entity *dl_se)
+{
+	return (dl_se->runtime <= 0);
+}
+
+/*
+ * This function implements the GRUB accounting rule:
+ * according to the GRUB reclaiming algorithm, the runtime is
+ * not decreased as "dq = -dt", but as
+ * "dq = -max{u / Umax, (1 - Uinact - Uextra)} dt",
+ * where u is the utilization of the task, Umax is the maximum reclaimable
+ * utilization, Uinact is the (per-runqueue) inactive utilization, computed
+ * as the difference between the "total runqueue utilization" and the
+ * runqueue active utilization, and Uextra is the (per runqueue) extra
+ * reclaimable utilization.
+ * Since rq->dl.running_bw and rq->dl.this_bw contain utilizations
+ * multiplied by 2^BW_SHIFT, the result has to be shifted right by
+ * BW_SHIFT.
+ * Since rq->dl.bw_ratio contains 1 / Umax multiplied by 2^RATIO_SHIFT,
+ * dl_bw is multiped by rq->dl.bw_ratio and shifted right by RATIO_SHIFT.
+ * Since delta is a 64 bit variable, to have an overflow its value
+ * should be larger than 2^(64 - 20 - 8), which is more than 64 seconds.
+ * So, overflow is not an issue here.
+ */
+static u64 grub_reclaim(u64 delta, struct rq *rq, struct sched_dl_entity *dl_se)
+{
+	u64 u_inact = rq->dl.this_bw - rq->dl.running_bw; /* Utot - Uact */
+	u64 u_act;
+	u64 u_act_min = (dl_se->dl_bw * rq->dl.bw_ratio) >> RATIO_SHIFT;
+
+	/*
+	 * Instead of computing max{u * bw_ratio, (1 - u_inact - u_extra)},
+	 * we compare u_inact + rq->dl.extra_bw with
+	 * 1 - (u * rq->dl.bw_ratio >> RATIO_SHIFT), because
+	 * u_inact + rq->dl.extra_bw can be larger than
+	 * 1 * (so, 1 - u_inact - rq->dl.extra_bw would be negative
+	 * leading to wrong results)
+	 */
+	if (u_inact + rq->dl.extra_bw > BW_UNIT - u_act_min)
+		u_act = u_act_min;
+	else
+		u_act = BW_UNIT - u_inact - rq->dl.extra_bw;
+
+	return (delta * u_act) >> BW_SHIFT;
+}
+
+/*
+ * Update the current task's runtime statistics (provided it is still
+ * a -deadline task and has not been removed from the dl_rq).
+ */
+static void update_curr_dl(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+	struct sched_dl_entity *dl_se = &curr->dl;
+	u64 delta_exec, scaled_delta_exec;
+	int cpu = cpu_of(rq);
+	u64 now;
+
+	if (!dl_task(curr) || !on_dl_rq(dl_se))
+		return;
+
+	/*
+	 * Consumed budget is computed considering the time as
+	 * observed by schedulable tasks (excluding time spent
+	 * in hardirq context, etc.). Deadlines are instead
+	 * computed using hard walltime. This seems to be the more
+	 * natural solution, but the full ramifications of this
+	 * approach need further study.
+	 */
+	now = rq_clock_task(rq);
+	delta_exec = now - curr->se.exec_start;
+	if (unlikely((s64)delta_exec <= 0)) {
+		if (unlikely(dl_se->dl_yielded))
+			goto throttle;
+		return;
+	}
+
+	schedstat_set(curr->stats.exec_max,
+		      max(curr->stats.exec_max, delta_exec));
+
+	trace_sched_stat_runtime(curr, delta_exec, 0);
+
+	update_current_exec_runtime(curr, now, delta_exec);
+
+	if (dl_entity_is_special(dl_se))
+		return;
+
+	/*
+	 * For tasks that participate in GRUB, we implement GRUB-PA: the
+	 * spare reclaimed bandwidth is used to clock down frequency.
+	 *
+	 * For the others, we still need to scale reservation parameters
+	 * according to current frequency and CPU maximum capacity.
+	 */
+	if (unlikely(dl_se->flags & SCHED_FLAG_RECLAIM)) {
+		scaled_delta_exec = grub_reclaim(delta_exec,
+						 rq,
+						 &curr->dl);
+	} else {
+		unsigned long scale_freq = arch_scale_freq_capacity(cpu);
+		unsigned long scale_cpu = arch_scale_cpu_capacity(cpu);
+
+		scaled_delta_exec = cap_scale(delta_exec, scale_freq);
+		scaled_delta_exec = cap_scale(scaled_delta_exec, scale_cpu);
+	}
+
+	dl_se->runtime -= scaled_delta_exec;
+
+throttle:
+	if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) {
+		dl_se->dl_throttled = 1;
+
+		/* If requested, inform the user about runtime overruns. */
+		if (dl_runtime_exceeded(dl_se) &&
+		    (dl_se->flags & SCHED_FLAG_DL_OVERRUN))
+			dl_se->dl_overrun = 1;
+
+		__dequeue_task_dl(rq, curr, 0);
+		if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(curr)))
+			enqueue_task_dl(rq, curr, ENQUEUE_REPLENISH);
+
+		if (!is_leftmost(curr, &rq->dl))
+			resched_curr(rq);
+	}
+
+	/*
+	 * Because -- for now -- we share the rt bandwidth, we need to
+	 * account our runtime there too, otherwise actual rt tasks
+	 * would be able to exceed the shared quota.
+	 *
+	 * Account to the root rt group for now.
+	 *
+	 * The solution we're working towards is having the RT groups scheduled
+	 * using deadline servers -- however there's a few nasties to figure
+	 * out before that can happen.
+	 */
+	if (rt_bandwidth_enabled()) {
+		struct rt_rq *rt_rq = &rq->rt;
+
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		/*
+		 * We'll let actual RT tasks worry about the overflow here, we
+		 * have our own CBS to keep us inline; only account when RT
+		 * bandwidth is relevant.
+		 */
+		if (sched_rt_bandwidth_account(rt_rq))
+			rt_rq->rt_time += delta_exec;
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+	}
+}
+
+static enum hrtimer_restart inactive_task_timer(struct hrtimer *timer)
+{
+	struct sched_dl_entity *dl_se = container_of(timer,
+						     struct sched_dl_entity,
+						     inactive_timer);
+	struct task_struct *p = dl_task_of(dl_se);
+	struct rq_flags rf;
+	struct rq *rq;
+
+	rq = task_rq_lock(p, &rf);
+
+	sched_clock_tick();
+	update_rq_clock(rq);
+
+	if (!dl_task(p) || READ_ONCE(p->__state) == TASK_DEAD) {
+		struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
+
+		if (READ_ONCE(p->__state) == TASK_DEAD && dl_se->dl_non_contending) {
+			sub_running_bw(&p->dl, dl_rq_of_se(&p->dl));
+			sub_rq_bw(&p->dl, dl_rq_of_se(&p->dl));
+			dl_se->dl_non_contending = 0;
+		}
+
+		raw_spin_lock(&dl_b->lock);
+		__dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p)));
+		raw_spin_unlock(&dl_b->lock);
+		__dl_clear_params(p);
+
+		goto unlock;
+	}
+	if (dl_se->dl_non_contending == 0)
+		goto unlock;
+
+	sub_running_bw(dl_se, &rq->dl);
+	dl_se->dl_non_contending = 0;
+unlock:
+	task_rq_unlock(rq, p, &rf);
+	put_task_struct(p);
+
+	return HRTIMER_NORESTART;
+}
+
+void init_dl_inactive_task_timer(struct sched_dl_entity *dl_se)
+{
+	struct hrtimer *timer = &dl_se->inactive_timer;
+
+	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	timer->function = inactive_task_timer;
+}
+
+#define __node_2_dle(node) \
+	rb_entry((node), struct sched_dl_entity, rb_node)
+
+#ifdef CONFIG_SMP
+
+static void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline)
+{
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+
+	if (dl_rq->earliest_dl.curr == 0 ||
+	    dl_time_before(deadline, dl_rq->earliest_dl.curr)) {
+		if (dl_rq->earliest_dl.curr == 0)
+			cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_HIGHER);
+		dl_rq->earliest_dl.curr = deadline;
+		cpudl_set(&rq->rd->cpudl, rq->cpu, deadline);
+	}
+}
+
+static void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline)
+{
+	struct rq *rq = rq_of_dl_rq(dl_rq);
+
+	/*
+	 * Since we may have removed our earliest (and/or next earliest)
+	 * task we must recompute them.
+	 */
+	if (!dl_rq->dl_nr_running) {
+		dl_rq->earliest_dl.curr = 0;
+		dl_rq->earliest_dl.next = 0;
+		cpudl_clear(&rq->rd->cpudl, rq->cpu);
+		cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
+	} else {
+		struct rb_node *leftmost = rb_first_cached(&dl_rq->root);
+		struct sched_dl_entity *entry = __node_2_dle(leftmost);
+
+		dl_rq->earliest_dl.curr = entry->deadline;
+		cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline);
+	}
+}
+
+#else
+
+static inline void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {}
+static inline void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) {}
+
+#endif /* CONFIG_SMP */
+
+static inline
+void inc_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	int prio = dl_task_of(dl_se)->prio;
+	u64 deadline = dl_se->deadline;
+
+	WARN_ON(!dl_prio(prio));
+	dl_rq->dl_nr_running++;
+	add_nr_running(rq_of_dl_rq(dl_rq), 1);
+
+	inc_dl_deadline(dl_rq, deadline);
+	inc_dl_migration(dl_se, dl_rq);
+}
+
+static inline
+void dec_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
+{
+	int prio = dl_task_of(dl_se)->prio;
+
+	WARN_ON(!dl_prio(prio));
+	WARN_ON(!dl_rq->dl_nr_running);
+	dl_rq->dl_nr_running--;
+	sub_nr_running(rq_of_dl_rq(dl_rq), 1);
+
+	dec_dl_deadline(dl_rq, dl_se->deadline);
+	dec_dl_migration(dl_se, dl_rq);
+}
+
+static inline bool __dl_less(struct rb_node *a, const struct rb_node *b)
+{
+	return dl_time_before(__node_2_dle(a)->deadline, __node_2_dle(b)->deadline);
+}
+
+static inline struct sched_statistics *
+__schedstats_from_dl_se(struct sched_dl_entity *dl_se)
+{
+	return &dl_task_of(dl_se)->stats;
+}
+
+static inline void
+update_stats_wait_start_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se)
+{
+	struct sched_statistics *stats;
+
+	if (!schedstat_enabled())
+		return;
+
+	stats = __schedstats_from_dl_se(dl_se);
+	__update_stats_wait_start(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats);
+}
+
+static inline void
+update_stats_wait_end_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se)
+{
+	struct sched_statistics *stats;
+
+	if (!schedstat_enabled())
+		return;
+
+	stats = __schedstats_from_dl_se(dl_se);
+	__update_stats_wait_end(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats);
+}
+
+static inline void
+update_stats_enqueue_sleeper_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se)
+{
+	struct sched_statistics *stats;
+
+	if (!schedstat_enabled())
+		return;
+
+	stats = __schedstats_from_dl_se(dl_se);
+	__update_stats_enqueue_sleeper(rq_of_dl_rq(dl_rq), dl_task_of(dl_se), stats);
+}
+
+static inline void
+update_stats_enqueue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se,
+			int flags)
+{
+	if (!schedstat_enabled())
+		return;
+
+	if (flags & ENQUEUE_WAKEUP)
+		update_stats_enqueue_sleeper_dl(dl_rq, dl_se);
+}
+
+static inline void
+update_stats_dequeue_dl(struct dl_rq *dl_rq, struct sched_dl_entity *dl_se,
+			int flags)
+{
+	struct task_struct *p = dl_task_of(dl_se);
+
+	if (!schedstat_enabled())
+		return;
+
+	if ((flags & DEQUEUE_SLEEP)) {
+		unsigned int state;
+
+		state = READ_ONCE(p->__state);
+		if (state & TASK_INTERRUPTIBLE)
+			__schedstat_set(p->stats.sleep_start,
+					rq_clock(rq_of_dl_rq(dl_rq)));
+
+		if (state & TASK_UNINTERRUPTIBLE)
+			__schedstat_set(p->stats.block_start,
+					rq_clock(rq_of_dl_rq(dl_rq)));
+	}
+}
+
+static void __enqueue_dl_entity(struct sched_dl_entity *dl_se)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+
+	WARN_ON_ONCE(!RB_EMPTY_NODE(&dl_se->rb_node));
+
+	rb_add_cached(&dl_se->rb_node, &dl_rq->root, __dl_less);
+
+	inc_dl_tasks(dl_se, dl_rq);
+}
+
+static void __dequeue_dl_entity(struct sched_dl_entity *dl_se)
+{
+	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
+
+	if (RB_EMPTY_NODE(&dl_se->rb_node))
+		return;
+
+	rb_erase_cached(&dl_se->rb_node, &dl_rq->root);
+
+	RB_CLEAR_NODE(&dl_se->rb_node);
+
+	dec_dl_tasks(dl_se, dl_rq);
+}
+
+static void
+enqueue_dl_entity(struct sched_dl_entity *dl_se, int flags)
+{
+	WARN_ON_ONCE(on_dl_rq(dl_se));
+
+	update_stats_enqueue_dl(dl_rq_of_se(dl_se), dl_se, flags);
+
+	/*
+	 * If this is a wakeup or a new instance, the scheduling
+	 * parameters of the task might need updating. Otherwise,
+	 * we want a replenishment of its runtime.
+	 */
+	if (flags & ENQUEUE_WAKEUP) {
+		task_contending(dl_se, flags);
+		update_dl_entity(dl_se);
+	} else if (flags & ENQUEUE_REPLENISH) {
+		replenish_dl_entity(dl_se);
+	} else if ((flags & ENQUEUE_RESTORE) &&
+		  dl_time_before(dl_se->deadline,
+				 rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) {
+		setup_new_dl_entity(dl_se);
+	}
+
+	__enqueue_dl_entity(dl_se);
+}
+
+static void dequeue_dl_entity(struct sched_dl_entity *dl_se)
+{
+	__dequeue_dl_entity(dl_se);
+}
+
+static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
+{
+	if (is_dl_boosted(&p->dl)) {
+		/*
+		 * Because of delays in the detection of the overrun of a
+		 * thread's runtime, it might be the case that a thread
+		 * goes to sleep in a rt mutex with negative runtime. As
+		 * a consequence, the thread will be throttled.
+		 *
+		 * While waiting for the mutex, this thread can also be
+		 * boosted via PI, resulting in a thread that is throttled
+		 * and boosted at the same time.
+		 *
+		 * In this case, the boost overrides the throttle.
+		 */
+		if (p->dl.dl_throttled) {
+			/*
+			 * The replenish timer needs to be canceled. No
+			 * problem if it fires concurrently: boosted threads
+			 * are ignored in dl_task_timer().
+			 */
+			hrtimer_try_to_cancel(&p->dl.dl_timer);
+			p->dl.dl_throttled = 0;
+		}
+	} else if (!dl_prio(p->normal_prio)) {
+		/*
+		 * Special case in which we have a !SCHED_DEADLINE task that is going
+		 * to be deboosted, but exceeds its runtime while doing so. No point in
+		 * replenishing it, as it's going to return back to its original
+		 * scheduling class after this. If it has been throttled, we need to
+		 * clear the flag, otherwise the task may wake up as throttled after
+		 * being boosted again with no means to replenish the runtime and clear
+		 * the throttle.
+		 */
+		p->dl.dl_throttled = 0;
+		if (!(flags & ENQUEUE_REPLENISH))
+			printk_deferred_once("sched: DL de-boosted task PID %d: REPLENISH flag missing\n",
+					     task_pid_nr(p));
+
+		return;
+	}
+
+	/*
+	 * Check if a constrained deadline task was activated
+	 * after the deadline but before the next period.
+	 * If that is the case, the task will be throttled and
+	 * the replenishment timer will be set to the next period.
+	 */
+	if (!p->dl.dl_throttled && !dl_is_implicit(&p->dl))
+		dl_check_constrained_dl(&p->dl);
+
+	if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & ENQUEUE_RESTORE) {
+		add_rq_bw(&p->dl, &rq->dl);
+		add_running_bw(&p->dl, &rq->dl);
+	}
+
+	/*
+	 * If p is throttled, we do not enqueue it. In fact, if it exhausted
+	 * its budget it needs a replenishment and, since it now is on
+	 * its rq, the bandwidth timer callback (which clearly has not
+	 * run yet) will take care of this.
+	 * However, the active utilization does not depend on the fact
+	 * that the task is on the runqueue or not (but depends on the
+	 * task's state - in GRUB parlance, "inactive" vs "active contending").
+	 * In other words, even if a task is throttled its utilization must
+	 * be counted in the active utilization; hence, we need to call
+	 * add_running_bw().
+	 */
+	if (p->dl.dl_throttled && !(flags & ENQUEUE_REPLENISH)) {
+		if (flags & ENQUEUE_WAKEUP)
+			task_contending(&p->dl, flags);
+
+		return;
+	}
+
+	check_schedstat_required();
+	update_stats_wait_start_dl(dl_rq_of_se(&p->dl), &p->dl);
+
+	enqueue_dl_entity(&p->dl, flags);
+
+	if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
+		enqueue_pushable_dl_task(rq, p);
+}
+
+static void __dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
+{
+	update_stats_dequeue_dl(&rq->dl, &p->dl, flags);
+	dequeue_dl_entity(&p->dl);
+	dequeue_pushable_dl_task(rq, p);
+}
+
+static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
+{
+	update_curr_dl(rq);
+	__dequeue_task_dl(rq, p, flags);
+
+	if (p->on_rq == TASK_ON_RQ_MIGRATING || flags & DEQUEUE_SAVE) {
+		sub_running_bw(&p->dl, &rq->dl);
+		sub_rq_bw(&p->dl, &rq->dl);
+	}
+
+	/*
+	 * This check allows to start the inactive timer (or to immediately
+	 * decrease the active utilization, if needed) in two cases:
+	 * when the task blocks and when it is terminating
+	 * (p->state == TASK_DEAD). We can handle the two cases in the same
+	 * way, because from GRUB's point of view the same thing is happening
+	 * (the task moves from "active contending" to "active non contending"
+	 * or "inactive")
+	 */
+	if (flags & DEQUEUE_SLEEP)
+		task_non_contending(p);
+}
+
+/*
+ * Yield task semantic for -deadline tasks is:
+ *
+ *   get off from the CPU until our next instance, with
+ *   a new runtime. This is of little use now, since we
+ *   don't have a bandwidth reclaiming mechanism. Anyway,
+ *   bandwidth reclaiming is planned for the future, and
+ *   yield_task_dl will indicate that some spare budget
+ *   is available for other task instances to use it.
+ */
+static void yield_task_dl(struct rq *rq)
+{
+	/*
+	 * We make the task go to sleep until its current deadline by
+	 * forcing its runtime to zero. This way, update_curr_dl() stops
+	 * it and the bandwidth timer will wake it up and will give it
+	 * new scheduling parameters (thanks to dl_yielded=1).
+	 */
+	rq->curr->dl.dl_yielded = 1;
+
+	update_rq_clock(rq);
+	update_curr_dl(rq);
+	/*
+	 * Tell update_rq_clock() that we've just updated,
+	 * so we don't do microscopic update in schedule()
+	 * and double the fastpath cost.
+	 */
+	rq_clock_skip_update(rq);
+}
+
+#ifdef CONFIG_SMP
+
+static inline bool dl_task_is_earliest_deadline(struct task_struct *p,
+						 struct rq *rq)
+{
+	return (!rq->dl.dl_nr_running ||
+		dl_time_before(p->dl.deadline,
+			       rq->dl.earliest_dl.curr));
+}
+
+static int find_later_rq(struct task_struct *task);
+
+static int
+select_task_rq_dl(struct task_struct *p, int cpu, int flags)
+{
+	struct task_struct *curr;
+	bool select_rq;
+	struct rq *rq;
+
+	if (!(flags & WF_TTWU))
+		goto out;
+
+	rq = cpu_rq(cpu);
+
+	rcu_read_lock();
+	curr = READ_ONCE(rq->curr); /* unlocked access */
+
+	/*
+	 * If we are dealing with a -deadline task, we must
+	 * decide where to wake it up.
+	 * If it has a later deadline and the current task
+	 * on this rq can't move (provided the waking task
+	 * can!) we prefer to send it somewhere else. On the
+	 * other hand, if it has a shorter deadline, we
+	 * try to make it stay here, it might be important.
+	 */
+	select_rq = unlikely(dl_task(curr)) &&
+		    (curr->nr_cpus_allowed < 2 ||
+		     !dl_entity_preempt(&p->dl, &curr->dl)) &&
+		    p->nr_cpus_allowed > 1;
+
+	/*
+	 * Take the capacity of the CPU into account to
+	 * ensure it fits the requirement of the task.
+	 */
+	if (sched_asym_cpucap_active())
+		select_rq |= !dl_task_fits_capacity(p, cpu);
+
+	if (select_rq) {
+		int target = find_later_rq(p);
+
+		if (target != -1 &&
+		    dl_task_is_earliest_deadline(p, cpu_rq(target)))
+			cpu = target;
+	}
+	rcu_read_unlock();
+
+out:
+	return cpu;
+}
+
+static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (READ_ONCE(p->__state) != TASK_WAKING)
+		return;
+
+	rq = task_rq(p);
+	/*
+	 * Since p->state == TASK_WAKING, set_task_cpu() has been called
+	 * from try_to_wake_up(). Hence, p->pi_lock is locked, but
+	 * rq->lock is not... So, lock it
+	 */
+	rq_lock(rq, &rf);
+	if (p->dl.dl_non_contending) {
+		update_rq_clock(rq);
+		sub_running_bw(&p->dl, &rq->dl);
+		p->dl.dl_non_contending = 0;
+		/*
+		 * If the timer handler is currently running and the
+		 * timer cannot be canceled, inactive_task_timer()
+		 * will see that dl_not_contending is not set, and
+		 * will not touch the rq's active utilization,
+		 * so we are still safe.
+		 */
+		if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1)
+			put_task_struct(p);
+	}
+	sub_rq_bw(&p->dl, &rq->dl);
+	rq_unlock(rq, &rf);
+}
+
+static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
+{
+	/*
+	 * Current can't be migrated, useless to reschedule,
+	 * let's hope p can move out.
+	 */
+	if (rq->curr->nr_cpus_allowed == 1 ||
+	    !cpudl_find(&rq->rd->cpudl, rq->curr, NULL))
+		return;
+
+	/*
+	 * p is migratable, so let's not schedule it and
+	 * see if it is pushed or pulled somewhere else.
+	 */
+	if (p->nr_cpus_allowed != 1 &&
+	    cpudl_find(&rq->rd->cpudl, p, NULL))
+		return;
+
+	resched_curr(rq);
+}
+
+static int balance_dl(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
+{
+	if (!on_dl_rq(&p->dl) && need_pull_dl_task(rq, p)) {
+		/*
+		 * This is OK, because current is on_cpu, which avoids it being
+		 * picked for load-balance and preemption/IRQs are still
+		 * disabled avoiding further scheduler activity on it and we've
+		 * not yet started the picking loop.
+		 */
+		rq_unpin_lock(rq, rf);
+		pull_dl_task(rq);
+		rq_repin_lock(rq, rf);
+	}
+
+	return sched_stop_runnable(rq) || sched_dl_runnable(rq);
+}
+#endif /* CONFIG_SMP */
+
+/*
+ * Only called when both the current and waking task are -deadline
+ * tasks.
+ */
+static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p,
+				  int flags)
+{
+	if (dl_entity_preempt(&p->dl, &rq->curr->dl)) {
+		resched_curr(rq);
+		return;
+	}
+
+#ifdef CONFIG_SMP
+	/*
+	 * In the unlikely case current and p have the same deadline
+	 * let us try to decide what's the best thing to do...
+	 */
+	if ((p->dl.deadline == rq->curr->dl.deadline) &&
+	    !test_tsk_need_resched(rq->curr))
+		check_preempt_equal_dl(rq, p);
+#endif /* CONFIG_SMP */
+}
+
+#ifdef CONFIG_SCHED_HRTICK
+static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
+{
+	hrtick_start(rq, p->dl.runtime);
+}
+#else /* !CONFIG_SCHED_HRTICK */
+static void start_hrtick_dl(struct rq *rq, struct task_struct *p)
+{
+}
+#endif
+
+static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+	struct dl_rq *dl_rq = &rq->dl;
+
+	p->se.exec_start = rq_clock_task(rq);
+	if (on_dl_rq(&p->dl))
+		update_stats_wait_end_dl(dl_rq, dl_se);
+
+	/* You can't push away the running task */
+	dequeue_pushable_dl_task(rq, p);
+
+	if (!first)
+		return;
+
+	if (hrtick_enabled_dl(rq))
+		start_hrtick_dl(rq, p);
+
+	if (rq->curr->sched_class != &dl_sched_class)
+		update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0);
+
+	deadline_queue_push_tasks(rq);
+}
+
+static struct sched_dl_entity *pick_next_dl_entity(struct dl_rq *dl_rq)
+{
+	struct rb_node *left = rb_first_cached(&dl_rq->root);
+
+	if (!left)
+		return NULL;
+
+	return __node_2_dle(left);
+}
+
+static struct task_struct *pick_task_dl(struct rq *rq)
+{
+	struct sched_dl_entity *dl_se;
+	struct dl_rq *dl_rq = &rq->dl;
+	struct task_struct *p;
+
+	if (!sched_dl_runnable(rq))
+		return NULL;
+
+	dl_se = pick_next_dl_entity(dl_rq);
+	WARN_ON_ONCE(!dl_se);
+	p = dl_task_of(dl_se);
+
+	return p;
+}
+
+static struct task_struct *pick_next_task_dl(struct rq *rq)
+{
+	struct task_struct *p;
+
+	p = pick_task_dl(rq);
+	if (p)
+		set_next_task_dl(rq, p, true);
+
+	return p;
+}
+
+static void put_prev_task_dl(struct rq *rq, struct task_struct *p)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+	struct dl_rq *dl_rq = &rq->dl;
+
+	if (on_dl_rq(&p->dl))
+		update_stats_wait_start_dl(dl_rq, dl_se);
+
+	update_curr_dl(rq);
+
+	update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1);
+	if (on_dl_rq(&p->dl) && p->nr_cpus_allowed > 1)
+		enqueue_pushable_dl_task(rq, p);
+}
+
+/*
+ * scheduler tick hitting a task of our scheduling class.
+ *
+ * NOTE: This function can be called remotely by the tick offload that
+ * goes along full dynticks. Therefore no local assumption can be made
+ * and everything must be accessed through the @rq and @curr passed in
+ * parameters.
+ */
+static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued)
+{
+	update_curr_dl(rq);
+
+	update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1);
+	/*
+	 * Even when we have runtime, update_curr_dl() might have resulted in us
+	 * not being the leftmost task anymore. In that case NEED_RESCHED will
+	 * be set and schedule() will start a new hrtick for the next task.
+	 */
+	if (hrtick_enabled_dl(rq) && queued && p->dl.runtime > 0 &&
+	    is_leftmost(p, &rq->dl))
+		start_hrtick_dl(rq, p);
+}
+
+static void task_fork_dl(struct task_struct *p)
+{
+	/*
+	 * SCHED_DEADLINE tasks cannot fork and this is achieved through
+	 * sched_fork()
+	 */
+}
+
+#ifdef CONFIG_SMP
+
+/* Only try algorithms three times */
+#define DL_MAX_TRIES 3
+
+static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu)
+{
+	if (!task_on_cpu(rq, p) &&
+	    cpumask_test_cpu(cpu, &p->cpus_mask))
+		return 1;
+	return 0;
+}
+
+/*
+ * Return the earliest pushable rq's task, which is suitable to be executed
+ * on the CPU, NULL otherwise:
+ */
+static struct task_struct *pick_earliest_pushable_dl_task(struct rq *rq, int cpu)
+{
+	struct task_struct *p = NULL;
+	struct rb_node *next_node;
+
+	if (!has_pushable_dl_tasks(rq))
+		return NULL;
+
+	next_node = rb_first_cached(&rq->dl.pushable_dl_tasks_root);
+
+next_node:
+	if (next_node) {
+		p = __node_2_pdl(next_node);
+
+		if (pick_dl_task(rq, p, cpu))
+			return p;
+
+		next_node = rb_next(next_node);
+		goto next_node;
+	}
+
+	return NULL;
+}
+
+static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl);
+
+static int find_later_rq(struct task_struct *task)
+{
+	struct sched_domain *sd;
+	struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl);
+	int this_cpu = smp_processor_id();
+	int cpu = task_cpu(task);
+
+	/* Make sure the mask is initialized first */
+	if (unlikely(!later_mask))
+		return -1;
+
+	if (task->nr_cpus_allowed == 1)
+		return -1;
+
+	/*
+	 * We have to consider system topology and task affinity
+	 * first, then we can look for a suitable CPU.
+	 */
+	if (!cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask))
+		return -1;
+
+	/*
+	 * If we are here, some targets have been found, including
+	 * the most suitable which is, among the runqueues where the
+	 * current tasks have later deadlines than the task's one, the
+	 * rq with the latest possible one.
+	 *
+	 * Now we check how well this matches with task's
+	 * affinity and system topology.
+	 *
+	 * The last CPU where the task run is our first
+	 * guess, since it is most likely cache-hot there.
+	 */
+	if (cpumask_test_cpu(cpu, later_mask))
+		return cpu;
+	/*
+	 * Check if this_cpu is to be skipped (i.e., it is
+	 * not in the mask) or not.
+	 */
+	if (!cpumask_test_cpu(this_cpu, later_mask))
+		this_cpu = -1;
+
+	rcu_read_lock();
+	for_each_domain(cpu, sd) {
+		if (sd->flags & SD_WAKE_AFFINE) {
+			int best_cpu;
+
+			/*
+			 * If possible, preempting this_cpu is
+			 * cheaper than migrating.
+			 */
+			if (this_cpu != -1 &&
+			    cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
+				rcu_read_unlock();
+				return this_cpu;
+			}
+
+			best_cpu = cpumask_any_and_distribute(later_mask,
+							      sched_domain_span(sd));
+			/*
+			 * Last chance: if a CPU being in both later_mask
+			 * and current sd span is valid, that becomes our
+			 * choice. Of course, the latest possible CPU is
+			 * already under consideration through later_mask.
+			 */
+			if (best_cpu < nr_cpu_ids) {
+				rcu_read_unlock();
+				return best_cpu;
+			}
+		}
+	}
+	rcu_read_unlock();
+
+	/*
+	 * At this point, all our guesses failed, we just return
+	 * 'something', and let the caller sort the things out.
+	 */
+	if (this_cpu != -1)
+		return this_cpu;
+
+	cpu = cpumask_any_distribute(later_mask);
+	if (cpu < nr_cpu_ids)
+		return cpu;
+
+	return -1;
+}
+
+/* Locks the rq it finds */
+static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq)
+{
+	struct rq *later_rq = NULL;
+	int tries;
+	int cpu;
+
+	for (tries = 0; tries < DL_MAX_TRIES; tries++) {
+		cpu = find_later_rq(task);
+
+		if ((cpu == -1) || (cpu == rq->cpu))
+			break;
+
+		later_rq = cpu_rq(cpu);
+
+		if (!dl_task_is_earliest_deadline(task, later_rq)) {
+			/*
+			 * Target rq has tasks of equal or earlier deadline,
+			 * retrying does not release any lock and is unlikely
+			 * to yield a different result.
+			 */
+			later_rq = NULL;
+			break;
+		}
+
+		/* Retry if something changed. */
+		if (double_lock_balance(rq, later_rq)) {
+			if (unlikely(task_rq(task) != rq ||
+				     !cpumask_test_cpu(later_rq->cpu, &task->cpus_mask) ||
+				     task_on_cpu(rq, task) ||
+				     !dl_task(task) ||
+				     is_migration_disabled(task) ||
+				     !task_on_rq_queued(task))) {
+				double_unlock_balance(rq, later_rq);
+				later_rq = NULL;
+				break;
+			}
+		}
+
+		/*
+		 * If the rq we found has no -deadline task, or
+		 * its earliest one has a later deadline than our
+		 * task, the rq is a good one.
+		 */
+		if (dl_task_is_earliest_deadline(task, later_rq))
+			break;
+
+		/* Otherwise we try again. */
+		double_unlock_balance(rq, later_rq);
+		later_rq = NULL;
+	}
+
+	return later_rq;
+}
+
+static struct task_struct *pick_next_pushable_dl_task(struct rq *rq)
+{
+	struct task_struct *p;
+
+	if (!has_pushable_dl_tasks(rq))
+		return NULL;
+
+	p = __node_2_pdl(rb_first_cached(&rq->dl.pushable_dl_tasks_root));
+
+	WARN_ON_ONCE(rq->cpu != task_cpu(p));
+	WARN_ON_ONCE(task_current(rq, p));
+	WARN_ON_ONCE(p->nr_cpus_allowed <= 1);
+
+	WARN_ON_ONCE(!task_on_rq_queued(p));
+	WARN_ON_ONCE(!dl_task(p));
+
+	return p;
+}
+
+/*
+ * See if the non running -deadline tasks on this rq
+ * can be sent to some other CPU where they can preempt
+ * and start executing.
+ */
+static int push_dl_task(struct rq *rq)
+{
+	struct task_struct *next_task;
+	struct rq *later_rq;
+	int ret = 0;
+
+	if (!rq->dl.overloaded)
+		return 0;
+
+	next_task = pick_next_pushable_dl_task(rq);
+	if (!next_task)
+		return 0;
+
+retry:
+	/*
+	 * If next_task preempts rq->curr, and rq->curr
+	 * can move away, it makes sense to just reschedule
+	 * without going further in pushing next_task.
+	 */
+	if (dl_task(rq->curr) &&
+	    dl_time_before(next_task->dl.deadline, rq->curr->dl.deadline) &&
+	    rq->curr->nr_cpus_allowed > 1) {
+		resched_curr(rq);
+		return 0;
+	}
+
+	if (is_migration_disabled(next_task))
+		return 0;
+
+	if (WARN_ON(next_task == rq->curr))
+		return 0;
+
+	/* We might release rq lock */
+	get_task_struct(next_task);
+
+	/* Will lock the rq it'll find */
+	later_rq = find_lock_later_rq(next_task, rq);
+	if (!later_rq) {
+		struct task_struct *task;
+
+		/*
+		 * We must check all this again, since
+		 * find_lock_later_rq releases rq->lock and it is
+		 * then possible that next_task has migrated.
+		 */
+		task = pick_next_pushable_dl_task(rq);
+		if (task == next_task) {
+			/*
+			 * The task is still there. We don't try
+			 * again, some other CPU will pull it when ready.
+			 */
+			goto out;
+		}
+
+		if (!task)
+			/* No more tasks */
+			goto out;
+
+		put_task_struct(next_task);
+		next_task = task;
+		goto retry;
+	}
+
+	deactivate_task(rq, next_task, 0);
+	set_task_cpu(next_task, later_rq->cpu);
+	activate_task(later_rq, next_task, 0);
+	ret = 1;
+
+	resched_curr(later_rq);
+
+	double_unlock_balance(rq, later_rq);
+
+out:
+	put_task_struct(next_task);
+
+	return ret;
+}
+
+static void push_dl_tasks(struct rq *rq)
+{
+	/* push_dl_task() will return true if it moved a -deadline task */
+	while (push_dl_task(rq))
+		;
+}
+
+static void pull_dl_task(struct rq *this_rq)
+{
+	int this_cpu = this_rq->cpu, cpu;
+	struct task_struct *p, *push_task;
+	bool resched = false;
+	struct rq *src_rq;
+	u64 dmin = LONG_MAX;
+
+	if (likely(!dl_overloaded(this_rq)))
+		return;
+
+	/*
+	 * Match the barrier from dl_set_overloaded; this guarantees that if we
+	 * see overloaded we must also see the dlo_mask bit.
+	 */
+	smp_rmb();
+
+	for_each_cpu(cpu, this_rq->rd->dlo_mask) {
+		if (this_cpu == cpu)
+			continue;
+
+		src_rq = cpu_rq(cpu);
+
+		/*
+		 * It looks racy, abd it is! However, as in sched_rt.c,
+		 * we are fine with this.
+		 */
+		if (this_rq->dl.dl_nr_running &&
+		    dl_time_before(this_rq->dl.earliest_dl.curr,
+				   src_rq->dl.earliest_dl.next))
+			continue;
+
+		/* Might drop this_rq->lock */
+		push_task = NULL;
+		double_lock_balance(this_rq, src_rq);
+
+		/*
+		 * If there are no more pullable tasks on the
+		 * rq, we're done with it.
+		 */
+		if (src_rq->dl.dl_nr_running <= 1)
+			goto skip;
+
+		p = pick_earliest_pushable_dl_task(src_rq, this_cpu);
+
+		/*
+		 * We found a task to be pulled if:
+		 *  - it preempts our current (if there's one),
+		 *  - it will preempt the last one we pulled (if any).
+		 */
+		if (p && dl_time_before(p->dl.deadline, dmin) &&
+		    dl_task_is_earliest_deadline(p, this_rq)) {
+			WARN_ON(p == src_rq->curr);
+			WARN_ON(!task_on_rq_queued(p));
+
+			/*
+			 * Then we pull iff p has actually an earlier
+			 * deadline than the current task of its runqueue.
+			 */
+			if (dl_time_before(p->dl.deadline,
+					   src_rq->curr->dl.deadline))
+				goto skip;
+
+			if (is_migration_disabled(p)) {
+				push_task = get_push_task(src_rq);
+			} else {
+				deactivate_task(src_rq, p, 0);
+				set_task_cpu(p, this_cpu);
+				activate_task(this_rq, p, 0);
+				dmin = p->dl.deadline;
+				resched = true;
+			}
+
+			/* Is there any other task even earlier? */
+		}
+skip:
+		double_unlock_balance(this_rq, src_rq);
+
+		if (push_task) {
+			preempt_disable();
+			raw_spin_rq_unlock(this_rq);
+			stop_one_cpu_nowait(src_rq->cpu, push_cpu_stop,
+					    push_task, &src_rq->push_work);
+			preempt_enable();
+			raw_spin_rq_lock(this_rq);
+		}
+	}
+
+	if (resched)
+		resched_curr(this_rq);
+}
+
+/*
+ * Since the task is not running and a reschedule is not going to happen
+ * anytime soon on its runqueue, we try pushing it away now.
+ */
+static void task_woken_dl(struct rq *rq, struct task_struct *p)
+{
+	if (!task_on_cpu(rq, p) &&
+	    !test_tsk_need_resched(rq->curr) &&
+	    p->nr_cpus_allowed > 1 &&
+	    dl_task(rq->curr) &&
+	    (rq->curr->nr_cpus_allowed < 2 ||
+	     !dl_entity_preempt(&p->dl, &rq->curr->dl))) {
+		push_dl_tasks(rq);
+	}
+}
+
+static void set_cpus_allowed_dl(struct task_struct *p,
+				const struct cpumask *new_mask,
+				u32 flags)
+{
+	struct root_domain *src_rd;
+	struct rq *rq;
+
+	WARN_ON_ONCE(!dl_task(p));
+
+	rq = task_rq(p);
+	src_rd = rq->rd;
+	/*
+	 * Migrating a SCHED_DEADLINE task between exclusive
+	 * cpusets (different root_domains) entails a bandwidth
+	 * update. We already made space for us in the destination
+	 * domain (see cpuset_can_attach()).
+	 */
+	if (!cpumask_intersects(src_rd->span, new_mask)) {
+		struct dl_bw *src_dl_b;
+
+		src_dl_b = dl_bw_of(cpu_of(rq));
+		/*
+		 * We now free resources of the root_domain we are migrating
+		 * off. In the worst case, sched_setattr() may temporary fail
+		 * until we complete the update.
+		 */
+		raw_spin_lock(&src_dl_b->lock);
+		__dl_sub(src_dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p)));
+		raw_spin_unlock(&src_dl_b->lock);
+	}
+
+	set_cpus_allowed_common(p, new_mask, flags);
+}
+
+/* Assumes rq->lock is held */
+static void rq_online_dl(struct rq *rq)
+{
+	if (rq->dl.overloaded)
+		dl_set_overload(rq);
+
+	cpudl_set_freecpu(&rq->rd->cpudl, rq->cpu);
+	if (rq->dl.dl_nr_running > 0)
+		cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr);
+}
+
+/* Assumes rq->lock is held */
+static void rq_offline_dl(struct rq *rq)
+{
+	if (rq->dl.overloaded)
+		dl_clear_overload(rq);
+
+	cpudl_clear(&rq->rd->cpudl, rq->cpu);
+	cpudl_clear_freecpu(&rq->rd->cpudl, rq->cpu);
+}
+
+void __init init_sched_dl_class(void)
+{
+	unsigned int i;
+
+	for_each_possible_cpu(i)
+		zalloc_cpumask_var_node(&per_cpu(local_cpu_mask_dl, i),
+					GFP_KERNEL, cpu_to_node(i));
+}
+
+void dl_add_task_root_domain(struct task_struct *p)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+	struct dl_bw *dl_b;
+
+	raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
+	if (!dl_task(p)) {
+		raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags);
+		return;
+	}
+
+	rq = __task_rq_lock(p, &rf);
+
+	dl_b = &rq->rd->dl_bw;
+	raw_spin_lock(&dl_b->lock);
+
+	__dl_add(dl_b, p->dl.dl_bw, cpumask_weight(rq->rd->span));
+
+	raw_spin_unlock(&dl_b->lock);
+
+	task_rq_unlock(rq, p, &rf);
+}
+
+void dl_clear_root_domain(struct root_domain *rd)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&rd->dl_bw.lock, flags);
+	rd->dl_bw.total_bw = 0;
+	raw_spin_unlock_irqrestore(&rd->dl_bw.lock, flags);
+}
+
+#endif /* CONFIG_SMP */
+
+static void switched_from_dl(struct rq *rq, struct task_struct *p)
+{
+	/*
+	 * task_non_contending() can start the "inactive timer" (if the 0-lag
+	 * time is in the future). If the task switches back to dl before
+	 * the "inactive timer" fires, it can continue to consume its current
+	 * runtime using its current deadline. If it stays outside of
+	 * SCHED_DEADLINE until the 0-lag time passes, inactive_task_timer()
+	 * will reset the task parameters.
+	 */
+	if (task_on_rq_queued(p) && p->dl.dl_runtime)
+		task_non_contending(p);
+
+	/*
+	 * In case a task is setscheduled out from SCHED_DEADLINE we need to
+	 * keep track of that on its cpuset (for correct bandwidth tracking).
+	 */
+	dec_dl_tasks_cs(p);
+
+	if (!task_on_rq_queued(p)) {
+		/*
+		 * Inactive timer is armed. However, p is leaving DEADLINE and
+		 * might migrate away from this rq while continuing to run on
+		 * some other class. We need to remove its contribution from
+		 * this rq running_bw now, or sub_rq_bw (below) will complain.
+		 */
+		if (p->dl.dl_non_contending)
+			sub_running_bw(&p->dl, &rq->dl);
+		sub_rq_bw(&p->dl, &rq->dl);
+	}
+
+	/*
+	 * We cannot use inactive_task_timer() to invoke sub_running_bw()
+	 * at the 0-lag time, because the task could have been migrated
+	 * while SCHED_OTHER in the meanwhile.
+	 */
+	if (p->dl.dl_non_contending)
+		p->dl.dl_non_contending = 0;
+
+	/*
+	 * Since this might be the only -deadline task on the rq,
+	 * this is the right place to try to pull some other one
+	 * from an overloaded CPU, if any.
+	 */
+	if (!task_on_rq_queued(p) || rq->dl.dl_nr_running)
+		return;
+
+	deadline_queue_pull_task(rq);
+}
+
+/*
+ * When switching to -deadline, we may overload the rq, then
+ * we try to push someone off, if possible.
+ */
+static void switched_to_dl(struct rq *rq, struct task_struct *p)
+{
+	if (hrtimer_try_to_cancel(&p->dl.inactive_timer) == 1)
+		put_task_struct(p);
+
+	/*
+	 * In case a task is setscheduled to SCHED_DEADLINE we need to keep
+	 * track of that on its cpuset (for correct bandwidth tracking).
+	 */
+	inc_dl_tasks_cs(p);
+
+	/* If p is not queued we will update its parameters at next wakeup. */
+	if (!task_on_rq_queued(p)) {
+		add_rq_bw(&p->dl, &rq->dl);
+
+		return;
+	}
+
+	if (rq->curr != p) {
+#ifdef CONFIG_SMP
+		if (p->nr_cpus_allowed > 1 && rq->dl.overloaded)
+			deadline_queue_push_tasks(rq);
+#endif
+		if (dl_task(rq->curr))
+			check_preempt_curr_dl(rq, p, 0);
+		else
+			resched_curr(rq);
+	} else {
+		update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0);
+	}
+}
+
+/*
+ * If the scheduling parameters of a -deadline task changed,
+ * a push or pull operation might be needed.
+ */
+static void prio_changed_dl(struct rq *rq, struct task_struct *p,
+			    int oldprio)
+{
+	if (task_on_rq_queued(p) || task_current(rq, p)) {
+#ifdef CONFIG_SMP
+		/*
+		 * This might be too much, but unfortunately
+		 * we don't have the old deadline value, and
+		 * we can't argue if the task is increasing
+		 * or lowering its prio, so...
+		 */
+		if (!rq->dl.overloaded)
+			deadline_queue_pull_task(rq);
+
+		/*
+		 * If we now have a earlier deadline task than p,
+		 * then reschedule, provided p is still on this
+		 * runqueue.
+		 */
+		if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline))
+			resched_curr(rq);
+#else
+		/*
+		 * Again, we don't know if p has a earlier
+		 * or later deadline, so let's blindly set a
+		 * (maybe not needed) rescheduling point.
+		 */
+		resched_curr(rq);
+#endif /* CONFIG_SMP */
+	}
+}
+
+DEFINE_SCHED_CLASS(dl) = {
+
+	.enqueue_task		= enqueue_task_dl,
+	.dequeue_task		= dequeue_task_dl,
+	.yield_task		= yield_task_dl,
+
+	.check_preempt_curr	= check_preempt_curr_dl,
+
+	.pick_next_task		= pick_next_task_dl,
+	.put_prev_task		= put_prev_task_dl,
+	.set_next_task		= set_next_task_dl,
+
+#ifdef CONFIG_SMP
+	.balance		= balance_dl,
+	.pick_task		= pick_task_dl,
+	.select_task_rq		= select_task_rq_dl,
+	.migrate_task_rq	= migrate_task_rq_dl,
+	.set_cpus_allowed       = set_cpus_allowed_dl,
+	.rq_online              = rq_online_dl,
+	.rq_offline             = rq_offline_dl,
+	.task_woken		= task_woken_dl,
+	.find_lock_rq		= find_lock_later_rq,
+#endif
+
+	.task_tick		= task_tick_dl,
+	.task_fork              = task_fork_dl,
+
+	.prio_changed           = prio_changed_dl,
+	.switched_from		= switched_from_dl,
+	.switched_to		= switched_to_dl,
+
+	.update_curr		= update_curr_dl,
+};
+
+/* Used for dl_bw check and update, used under sched_rt_handler()::mutex */
+static u64 dl_generation;
+
+int sched_dl_global_validate(void)
+{
+	u64 runtime = global_rt_runtime();
+	u64 period = global_rt_period();
+	u64 new_bw = to_ratio(period, runtime);
+	u64 gen = ++dl_generation;
+	struct dl_bw *dl_b;
+	int cpu, cpus, ret = 0;
+	unsigned long flags;
+
+	/*
+	 * Here we want to check the bandwidth not being set to some
+	 * value smaller than the currently allocated bandwidth in
+	 * any of the root_domains.
+	 */
+	for_each_possible_cpu(cpu) {
+		rcu_read_lock_sched();
+
+		if (dl_bw_visited(cpu, gen))
+			goto next;
+
+		dl_b = dl_bw_of(cpu);
+		cpus = dl_bw_cpus(cpu);
+
+		raw_spin_lock_irqsave(&dl_b->lock, flags);
+		if (new_bw * cpus < dl_b->total_bw)
+			ret = -EBUSY;
+		raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+
+next:
+		rcu_read_unlock_sched();
+
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static void init_dl_rq_bw_ratio(struct dl_rq *dl_rq)
+{
+	if (global_rt_runtime() == RUNTIME_INF) {
+		dl_rq->bw_ratio = 1 << RATIO_SHIFT;
+		dl_rq->extra_bw = 1 << BW_SHIFT;
+	} else {
+		dl_rq->bw_ratio = to_ratio(global_rt_runtime(),
+			  global_rt_period()) >> (BW_SHIFT - RATIO_SHIFT);
+		dl_rq->extra_bw = to_ratio(global_rt_period(),
+						    global_rt_runtime());
+	}
+}
+
+void sched_dl_do_global(void)
+{
+	u64 new_bw = -1;
+	u64 gen = ++dl_generation;
+	struct dl_bw *dl_b;
+	int cpu;
+	unsigned long flags;
+
+	if (global_rt_runtime() != RUNTIME_INF)
+		new_bw = to_ratio(global_rt_period(), global_rt_runtime());
+
+	for_each_possible_cpu(cpu) {
+		rcu_read_lock_sched();
+
+		if (dl_bw_visited(cpu, gen)) {
+			rcu_read_unlock_sched();
+			continue;
+		}
+
+		dl_b = dl_bw_of(cpu);
+
+		raw_spin_lock_irqsave(&dl_b->lock, flags);
+		dl_b->bw = new_bw;
+		raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+
+		rcu_read_unlock_sched();
+		init_dl_rq_bw_ratio(&cpu_rq(cpu)->dl);
+	}
+}
+
+/*
+ * We must be sure that accepting a new task (or allowing changing the
+ * parameters of an existing one) is consistent with the bandwidth
+ * constraints. If yes, this function also accordingly updates the currently
+ * allocated bandwidth to reflect the new situation.
+ *
+ * This function is called while holding p's rq->lock.
+ */
+int sched_dl_overflow(struct task_struct *p, int policy,
+		      const struct sched_attr *attr)
+{
+	u64 period = attr->sched_period ?: attr->sched_deadline;
+	u64 runtime = attr->sched_runtime;
+	u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0;
+	int cpus, err = -1, cpu = task_cpu(p);
+	struct dl_bw *dl_b = dl_bw_of(cpu);
+	unsigned long cap;
+
+	if (attr->sched_flags & SCHED_FLAG_SUGOV)
+		return 0;
+
+	/* !deadline task may carry old deadline bandwidth */
+	if (new_bw == p->dl.dl_bw && task_has_dl_policy(p))
+		return 0;
+
+	/*
+	 * Either if a task, enters, leave, or stays -deadline but changes
+	 * its parameters, we may need to update accordingly the total
+	 * allocated bandwidth of the container.
+	 */
+	raw_spin_lock(&dl_b->lock);
+	cpus = dl_bw_cpus(cpu);
+	cap = dl_bw_capacity(cpu);
+
+	if (dl_policy(policy) && !task_has_dl_policy(p) &&
+	    !__dl_overflow(dl_b, cap, 0, new_bw)) {
+		if (hrtimer_active(&p->dl.inactive_timer))
+			__dl_sub(dl_b, p->dl.dl_bw, cpus);
+		__dl_add(dl_b, new_bw, cpus);
+		err = 0;
+	} else if (dl_policy(policy) && task_has_dl_policy(p) &&
+		   !__dl_overflow(dl_b, cap, p->dl.dl_bw, new_bw)) {
+		/*
+		 * XXX this is slightly incorrect: when the task
+		 * utilization decreases, we should delay the total
+		 * utilization change until the task's 0-lag point.
+		 * But this would require to set the task's "inactive
+		 * timer" when the task is not inactive.
+		 */
+		__dl_sub(dl_b, p->dl.dl_bw, cpus);
+		__dl_add(dl_b, new_bw, cpus);
+		dl_change_utilization(p, new_bw);
+		err = 0;
+	} else if (!dl_policy(policy) && task_has_dl_policy(p)) {
+		/*
+		 * Do not decrease the total deadline utilization here,
+		 * switched_from_dl() will take care to do it at the correct
+		 * (0-lag) time.
+		 */
+		err = 0;
+	}
+	raw_spin_unlock(&dl_b->lock);
+
+	return err;
+}
+
+/*
+ * This function initializes the sched_dl_entity of a newly becoming
+ * SCHED_DEADLINE task.
+ *
+ * Only the static values are considered here, the actual runtime and the
+ * absolute deadline will be properly calculated when the task is enqueued
+ * for the first time with its new policy.
+ */
+void __setparam_dl(struct task_struct *p, const struct sched_attr *attr)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+
+	dl_se->dl_runtime = attr->sched_runtime;
+	dl_se->dl_deadline = attr->sched_deadline;
+	dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline;
+	dl_se->flags = attr->sched_flags & SCHED_DL_FLAGS;
+	dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime);
+	dl_se->dl_density = to_ratio(dl_se->dl_deadline, dl_se->dl_runtime);
+}
+
+void __getparam_dl(struct task_struct *p, struct sched_attr *attr)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+
+	attr->sched_priority = p->rt_priority;
+	attr->sched_runtime = dl_se->dl_runtime;
+	attr->sched_deadline = dl_se->dl_deadline;
+	attr->sched_period = dl_se->dl_period;
+	attr->sched_flags &= ~SCHED_DL_FLAGS;
+	attr->sched_flags |= dl_se->flags;
+}
+
+/*
+ * This function validates the new parameters of a -deadline task.
+ * We ask for the deadline not being zero, and greater or equal
+ * than the runtime, as well as the period of being zero or
+ * greater than deadline. Furthermore, we have to be sure that
+ * user parameters are above the internal resolution of 1us (we
+ * check sched_runtime only since it is always the smaller one) and
+ * below 2^63 ns (we have to check both sched_deadline and
+ * sched_period, as the latter can be zero).
+ */
+bool __checkparam_dl(const struct sched_attr *attr)
+{
+	u64 period, max, min;
+
+	/* special dl tasks don't actually use any parameter */
+	if (attr->sched_flags & SCHED_FLAG_SUGOV)
+		return true;
+
+	/* deadline != 0 */
+	if (attr->sched_deadline == 0)
+		return false;
+
+	/*
+	 * Since we truncate DL_SCALE bits, make sure we're at least
+	 * that big.
+	 */
+	if (attr->sched_runtime < (1ULL << DL_SCALE))
+		return false;
+
+	/*
+	 * Since we use the MSB for wrap-around and sign issues, make
+	 * sure it's not set (mind that period can be equal to zero).
+	 */
+	if (attr->sched_deadline & (1ULL << 63) ||
+	    attr->sched_period & (1ULL << 63))
+		return false;
+
+	period = attr->sched_period;
+	if (!period)
+		period = attr->sched_deadline;
+
+	/* runtime <= deadline <= period (if period != 0) */
+	if (period < attr->sched_deadline ||
+	    attr->sched_deadline < attr->sched_runtime)
+		return false;
+
+	max = (u64)READ_ONCE(sysctl_sched_dl_period_max) * NSEC_PER_USEC;
+	min = (u64)READ_ONCE(sysctl_sched_dl_period_min) * NSEC_PER_USEC;
+
+	if (period < min || period > max)
+		return false;
+
+	return true;
+}
+
+/*
+ * This function clears the sched_dl_entity static params.
+ */
+void __dl_clear_params(struct task_struct *p)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+
+	dl_se->dl_runtime		= 0;
+	dl_se->dl_deadline		= 0;
+	dl_se->dl_period		= 0;
+	dl_se->flags			= 0;
+	dl_se->dl_bw			= 0;
+	dl_se->dl_density		= 0;
+
+	dl_se->dl_throttled		= 0;
+	dl_se->dl_yielded		= 0;
+	dl_se->dl_non_contending	= 0;
+	dl_se->dl_overrun		= 0;
+
+#ifdef CONFIG_RT_MUTEXES
+	dl_se->pi_se			= dl_se;
+#endif
+}
+
+bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr)
+{
+	struct sched_dl_entity *dl_se = &p->dl;
+
+	if (dl_se->dl_runtime != attr->sched_runtime ||
+	    dl_se->dl_deadline != attr->sched_deadline ||
+	    dl_se->dl_period != attr->sched_period ||
+	    dl_se->flags != (attr->sched_flags & SCHED_DL_FLAGS))
+		return true;
+
+	return false;
+}
+
+#ifdef CONFIG_SMP
+int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur,
+				 const struct cpumask *trial)
+{
+	unsigned long flags, cap;
+	struct dl_bw *cur_dl_b;
+	int ret = 1;
+
+	rcu_read_lock_sched();
+	cur_dl_b = dl_bw_of(cpumask_any(cur));
+	cap = __dl_bw_capacity(trial);
+	raw_spin_lock_irqsave(&cur_dl_b->lock, flags);
+	if (__dl_overflow(cur_dl_b, cap, 0, 0))
+		ret = 0;
+	raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags);
+	rcu_read_unlock_sched();
+
+	return ret;
+}
+
+enum dl_bw_request {
+	dl_bw_req_check_overflow = 0,
+	dl_bw_req_alloc,
+	dl_bw_req_free
+};
+
+static int dl_bw_manage(enum dl_bw_request req, int cpu, u64 dl_bw)
+{
+	unsigned long flags;
+	struct dl_bw *dl_b;
+	bool overflow = 0;
+
+	rcu_read_lock_sched();
+	dl_b = dl_bw_of(cpu);
+	raw_spin_lock_irqsave(&dl_b->lock, flags);
+
+	if (req == dl_bw_req_free) {
+		__dl_sub(dl_b, dl_bw, dl_bw_cpus(cpu));
+	} else {
+		unsigned long cap = dl_bw_capacity(cpu);
+
+		overflow = __dl_overflow(dl_b, cap, 0, dl_bw);
+
+		if (req == dl_bw_req_alloc && !overflow) {
+			/*
+			 * We reserve space in the destination
+			 * root_domain, as we can't fail after this point.
+			 * We will free resources in the source root_domain
+			 * later on (see set_cpus_allowed_dl()).
+			 */
+			__dl_add(dl_b, dl_bw, dl_bw_cpus(cpu));
+		}
+	}
+
+	raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+	rcu_read_unlock_sched();
+
+	return overflow ? -EBUSY : 0;
+}
+
+int dl_bw_check_overflow(int cpu)
+{
+	return dl_bw_manage(dl_bw_req_check_overflow, cpu, 0);
+}
+
+int dl_bw_alloc(int cpu, u64 dl_bw)
+{
+	return dl_bw_manage(dl_bw_req_alloc, cpu, dl_bw);
+}
+
+void dl_bw_free(int cpu, u64 dl_bw)
+{
+	dl_bw_manage(dl_bw_req_free, cpu, dl_bw);
+}
+#endif
+
+#ifdef CONFIG_SCHED_DEBUG
+void print_dl_stats(struct seq_file *m, int cpu)
+{
+	print_dl_rq(m, cpu, &cpu_rq(cpu)->dl);
+}
+#endif /* CONFIG_SCHED_DEBUG */
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
new file mode 100644
index 000000000..1637b65ba
--- /dev/null
+++ b/kernel/sched/debug.c
@@ -0,0 +1,1080 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/sched/debug.c
+ *
+ * Print the CFS rbtree and other debugging details
+ *
+ * Copyright(C) 2007, Red Hat, Inc., Ingo Molnar
+ */
+
+/*
+ * This allows printing both to /proc/sched_debug and
+ * to the console
+ */
+#define SEQ_printf(m, x...)			\
+ do {						\
+	if (m)					\
+		seq_printf(m, x);		\
+	else					\
+		pr_cont(x);			\
+ } while (0)
+
+/*
+ * Ease the printing of nsec fields:
+ */
+static long long nsec_high(unsigned long long nsec)
+{
+	if ((long long)nsec < 0) {
+		nsec = -nsec;
+		do_div(nsec, 1000000);
+		return -nsec;
+	}
+	do_div(nsec, 1000000);
+
+	return nsec;
+}
+
+static unsigned long nsec_low(unsigned long long nsec)
+{
+	if ((long long)nsec < 0)
+		nsec = -nsec;
+
+	return do_div(nsec, 1000000);
+}
+
+#define SPLIT_NS(x) nsec_high(x), nsec_low(x)
+
+#define SCHED_FEAT(name, enabled)	\
+	#name ,
+
+static const char * const sched_feat_names[] = {
+#include "features.h"
+};
+
+#undef SCHED_FEAT
+
+static int sched_feat_show(struct seq_file *m, void *v)
+{
+	int i;
+
+	for (i = 0; i < __SCHED_FEAT_NR; i++) {
+		if (!(sysctl_sched_features & (1UL << i)))
+			seq_puts(m, "NO_");
+		seq_printf(m, "%s ", sched_feat_names[i]);
+	}
+	seq_puts(m, "\n");
+
+	return 0;
+}
+
+#ifdef CONFIG_JUMP_LABEL
+
+#define jump_label_key__true  STATIC_KEY_INIT_TRUE
+#define jump_label_key__false STATIC_KEY_INIT_FALSE
+
+#define SCHED_FEAT(name, enabled)	\
+	jump_label_key__##enabled ,
+
+struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
+#include "features.h"
+};
+
+#undef SCHED_FEAT
+
+static void sched_feat_disable(int i)
+{
+	static_key_disable_cpuslocked(&sched_feat_keys[i]);
+}
+
+static void sched_feat_enable(int i)
+{
+	static_key_enable_cpuslocked(&sched_feat_keys[i]);
+}
+#else
+static void sched_feat_disable(int i) { };
+static void sched_feat_enable(int i) { };
+#endif /* CONFIG_JUMP_LABEL */
+
+static int sched_feat_set(char *cmp)
+{
+	int i;
+	int neg = 0;
+
+	if (strncmp(cmp, "NO_", 3) == 0) {
+		neg = 1;
+		cmp += 3;
+	}
+
+	i = match_string(sched_feat_names, __SCHED_FEAT_NR, cmp);
+	if (i < 0)
+		return i;
+
+	if (neg) {
+		sysctl_sched_features &= ~(1UL << i);
+		sched_feat_disable(i);
+	} else {
+		sysctl_sched_features |= (1UL << i);
+		sched_feat_enable(i);
+	}
+
+	return 0;
+}
+
+static ssize_t
+sched_feat_write(struct file *filp, const char __user *ubuf,
+		size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	char *cmp;
+	int ret;
+	struct inode *inode;
+
+	if (cnt > 63)
+		cnt = 63;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+	cmp = strstrip(buf);
+
+	/* Ensure the static_key remains in a consistent state */
+	inode = file_inode(filp);
+	cpus_read_lock();
+	inode_lock(inode);
+	ret = sched_feat_set(cmp);
+	inode_unlock(inode);
+	cpus_read_unlock();
+	if (ret < 0)
+		return ret;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static int sched_feat_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, sched_feat_show, NULL);
+}
+
+static const struct file_operations sched_feat_fops = {
+	.open		= sched_feat_open,
+	.write		= sched_feat_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+#ifdef CONFIG_SMP
+
+static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf,
+				   size_t cnt, loff_t *ppos)
+{
+	char buf[16];
+	unsigned int scaling;
+
+	if (cnt > 15)
+		cnt = 15;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+	buf[cnt] = '\0';
+
+	if (kstrtouint(buf, 10, &scaling))
+		return -EINVAL;
+
+	if (scaling >= SCHED_TUNABLESCALING_END)
+		return -EINVAL;
+
+	sysctl_sched_tunable_scaling = scaling;
+	if (sched_update_scaling())
+		return -EINVAL;
+
+	*ppos += cnt;
+	return cnt;
+}
+
+static int sched_scaling_show(struct seq_file *m, void *v)
+{
+	seq_printf(m, "%d\n", sysctl_sched_tunable_scaling);
+	return 0;
+}
+
+static int sched_scaling_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, sched_scaling_show, NULL);
+}
+
+static const struct file_operations sched_scaling_fops = {
+	.open		= sched_scaling_open,
+	.write		= sched_scaling_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+#endif /* SMP */
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+
+static ssize_t sched_dynamic_write(struct file *filp, const char __user *ubuf,
+				   size_t cnt, loff_t *ppos)
+{
+	char buf[16];
+	int mode;
+
+	if (cnt > 15)
+		cnt = 15;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+	mode = sched_dynamic_mode(strstrip(buf));
+	if (mode < 0)
+		return mode;
+
+	sched_dynamic_update(mode);
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static int sched_dynamic_show(struct seq_file *m, void *v)
+{
+	static const char * preempt_modes[] = {
+		"none", "voluntary", "full"
+	};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(preempt_modes); i++) {
+		if (preempt_dynamic_mode == i)
+			seq_puts(m, "(");
+		seq_puts(m, preempt_modes[i]);
+		if (preempt_dynamic_mode == i)
+			seq_puts(m, ")");
+
+		seq_puts(m, " ");
+	}
+
+	seq_puts(m, "\n");
+	return 0;
+}
+
+static int sched_dynamic_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, sched_dynamic_show, NULL);
+}
+
+static const struct file_operations sched_dynamic_fops = {
+	.open		= sched_dynamic_open,
+	.write		= sched_dynamic_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+#endif /* CONFIG_PREEMPT_DYNAMIC */
+
+__read_mostly bool sched_debug_verbose;
+
+static const struct seq_operations sched_debug_sops;
+
+static int sched_debug_open(struct inode *inode, struct file *filp)
+{
+	return seq_open(filp, &sched_debug_sops);
+}
+
+static const struct file_operations sched_debug_fops = {
+	.open		= sched_debug_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static struct dentry *debugfs_sched;
+
+static __init int sched_init_debug(void)
+{
+	struct dentry __maybe_unused *numa;
+
+	debugfs_sched = debugfs_create_dir("sched", NULL);
+
+	debugfs_create_file("features", 0644, debugfs_sched, NULL, &sched_feat_fops);
+	debugfs_create_bool("verbose", 0644, debugfs_sched, &sched_debug_verbose);
+#ifdef CONFIG_PREEMPT_DYNAMIC
+	debugfs_create_file("preempt", 0644, debugfs_sched, NULL, &sched_dynamic_fops);
+#endif
+
+	debugfs_create_u32("latency_ns", 0644, debugfs_sched, &sysctl_sched_latency);
+	debugfs_create_u32("min_granularity_ns", 0644, debugfs_sched, &sysctl_sched_min_granularity);
+	debugfs_create_u32("idle_min_granularity_ns", 0644, debugfs_sched, &sysctl_sched_idle_min_granularity);
+	debugfs_create_u32("wakeup_granularity_ns", 0644, debugfs_sched, &sysctl_sched_wakeup_granularity);
+
+	debugfs_create_u32("latency_warn_ms", 0644, debugfs_sched, &sysctl_resched_latency_warn_ms);
+	debugfs_create_u32("latency_warn_once", 0644, debugfs_sched, &sysctl_resched_latency_warn_once);
+
+#ifdef CONFIG_SMP
+	debugfs_create_file("tunable_scaling", 0644, debugfs_sched, NULL, &sched_scaling_fops);
+	debugfs_create_u32("migration_cost_ns", 0644, debugfs_sched, &sysctl_sched_migration_cost);
+	debugfs_create_u32("nr_migrate", 0644, debugfs_sched, &sysctl_sched_nr_migrate);
+
+	mutex_lock(&sched_domains_mutex);
+	update_sched_domain_debugfs();
+	mutex_unlock(&sched_domains_mutex);
+#endif
+
+#ifdef CONFIG_NUMA_BALANCING
+	numa = debugfs_create_dir("numa_balancing", debugfs_sched);
+
+	debugfs_create_u32("scan_delay_ms", 0644, numa, &sysctl_numa_balancing_scan_delay);
+	debugfs_create_u32("scan_period_min_ms", 0644, numa, &sysctl_numa_balancing_scan_period_min);
+	debugfs_create_u32("scan_period_max_ms", 0644, numa, &sysctl_numa_balancing_scan_period_max);
+	debugfs_create_u32("scan_size_mb", 0644, numa, &sysctl_numa_balancing_scan_size);
+	debugfs_create_u32("hot_threshold_ms", 0644, numa, &sysctl_numa_balancing_hot_threshold);
+#endif
+
+	debugfs_create_file("debug", 0444, debugfs_sched, NULL, &sched_debug_fops);
+
+	return 0;
+}
+late_initcall(sched_init_debug);
+
+#ifdef CONFIG_SMP
+
+static cpumask_var_t		sd_sysctl_cpus;
+static struct dentry		*sd_dentry;
+
+static int sd_flags_show(struct seq_file *m, void *v)
+{
+	unsigned long flags = *(unsigned int *)m->private;
+	int idx;
+
+	for_each_set_bit(idx, &flags, __SD_FLAG_CNT) {
+		seq_puts(m, sd_flag_debug[idx].name);
+		seq_puts(m, " ");
+	}
+	seq_puts(m, "\n");
+
+	return 0;
+}
+
+static int sd_flags_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, sd_flags_show, inode->i_private);
+}
+
+static const struct file_operations sd_flags_fops = {
+	.open		= sd_flags_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static void register_sd(struct sched_domain *sd, struct dentry *parent)
+{
+#define SDM(type, mode, member)	\
+	debugfs_create_##type(#member, mode, parent, &sd->member)
+
+	SDM(ulong, 0644, min_interval);
+	SDM(ulong, 0644, max_interval);
+	SDM(u64,   0644, max_newidle_lb_cost);
+	SDM(u32,   0644, busy_factor);
+	SDM(u32,   0644, imbalance_pct);
+	SDM(u32,   0644, cache_nice_tries);
+	SDM(str,   0444, name);
+
+#undef SDM
+
+	debugfs_create_file("flags", 0444, parent, &sd->flags, &sd_flags_fops);
+}
+
+void update_sched_domain_debugfs(void)
+{
+	int cpu, i;
+
+	/*
+	 * This can unfortunately be invoked before sched_debug_init() creates
+	 * the debug directory. Don't touch sd_sysctl_cpus until then.
+	 */
+	if (!debugfs_sched)
+		return;
+
+	if (!cpumask_available(sd_sysctl_cpus)) {
+		if (!alloc_cpumask_var(&sd_sysctl_cpus, GFP_KERNEL))
+			return;
+		cpumask_copy(sd_sysctl_cpus, cpu_possible_mask);
+	}
+
+	if (!sd_dentry)
+		sd_dentry = debugfs_create_dir("domains", debugfs_sched);
+
+	for_each_cpu(cpu, sd_sysctl_cpus) {
+		struct sched_domain *sd;
+		struct dentry *d_cpu;
+		char buf[32];
+
+		snprintf(buf, sizeof(buf), "cpu%d", cpu);
+		debugfs_lookup_and_remove(buf, sd_dentry);
+		d_cpu = debugfs_create_dir(buf, sd_dentry);
+
+		i = 0;
+		for_each_domain(cpu, sd) {
+			struct dentry *d_sd;
+
+			snprintf(buf, sizeof(buf), "domain%d", i);
+			d_sd = debugfs_create_dir(buf, d_cpu);
+
+			register_sd(sd, d_sd);
+			i++;
+		}
+
+		__cpumask_clear_cpu(cpu, sd_sysctl_cpus);
+	}
+}
+
+void dirty_sched_domain_sysctl(int cpu)
+{
+	if (cpumask_available(sd_sysctl_cpus))
+		__cpumask_set_cpu(cpu, sd_sysctl_cpus);
+}
+
+#endif /* CONFIG_SMP */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group *tg)
+{
+	struct sched_entity *se = tg->se[cpu];
+
+#define P(F)		SEQ_printf(m, "  .%-30s: %lld\n",	#F, (long long)F)
+#define P_SCHEDSTAT(F)	SEQ_printf(m, "  .%-30s: %lld\n",	\
+		#F, (long long)schedstat_val(stats->F))
+#define PN(F)		SEQ_printf(m, "  .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)F))
+#define PN_SCHEDSTAT(F)	SEQ_printf(m, "  .%-30s: %lld.%06ld\n", \
+		#F, SPLIT_NS((long long)schedstat_val(stats->F)))
+
+	if (!se)
+		return;
+
+	PN(se->exec_start);
+	PN(se->vruntime);
+	PN(se->sum_exec_runtime);
+
+	if (schedstat_enabled()) {
+		struct sched_statistics *stats;
+		stats = __schedstats_from_se(se);
+
+		PN_SCHEDSTAT(wait_start);
+		PN_SCHEDSTAT(sleep_start);
+		PN_SCHEDSTAT(block_start);
+		PN_SCHEDSTAT(sleep_max);
+		PN_SCHEDSTAT(block_max);
+		PN_SCHEDSTAT(exec_max);
+		PN_SCHEDSTAT(slice_max);
+		PN_SCHEDSTAT(wait_max);
+		PN_SCHEDSTAT(wait_sum);
+		P_SCHEDSTAT(wait_count);
+	}
+
+	P(se->load.weight);
+#ifdef CONFIG_SMP
+	P(se->avg.load_avg);
+	P(se->avg.util_avg);
+	P(se->avg.runnable_avg);
+#endif
+
+#undef PN_SCHEDSTAT
+#undef PN
+#undef P_SCHEDSTAT
+#undef P
+}
+#endif
+
+#ifdef CONFIG_CGROUP_SCHED
+static DEFINE_SPINLOCK(sched_debug_lock);
+static char group_path[PATH_MAX];
+
+static void task_group_path(struct task_group *tg, char *path, int plen)
+{
+	if (autogroup_path(tg, path, plen))
+		return;
+
+	cgroup_path(tg->css.cgroup, path, plen);
+}
+
+/*
+ * Only 1 SEQ_printf_task_group_path() caller can use the full length
+ * group_path[] for cgroup path. Other simultaneous callers will have
+ * to use a shorter stack buffer. A "..." suffix is appended at the end
+ * of the stack buffer so that it will show up in case the output length
+ * matches the given buffer size to indicate possible path name truncation.
+ */
+#define SEQ_printf_task_group_path(m, tg, fmt...)			\
+{									\
+	if (spin_trylock(&sched_debug_lock)) {				\
+		task_group_path(tg, group_path, sizeof(group_path));	\
+		SEQ_printf(m, fmt, group_path);				\
+		spin_unlock(&sched_debug_lock);				\
+	} else {							\
+		char buf[128];						\
+		char *bufend = buf + sizeof(buf) - 3;			\
+		task_group_path(tg, buf, bufend - buf);			\
+		strcpy(bufend - 1, "...");				\
+		SEQ_printf(m, fmt, buf);				\
+	}								\
+}
+#endif
+
+static void
+print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
+{
+	if (task_current(rq, p))
+		SEQ_printf(m, ">R");
+	else
+		SEQ_printf(m, " %c", task_state_to_char(p));
+
+	SEQ_printf(m, " %15s %5d %9Ld.%06ld %9Ld %5d ",
+		p->comm, task_pid_nr(p),
+		SPLIT_NS(p->se.vruntime),
+		(long long)(p->nvcsw + p->nivcsw),
+		p->prio);
+
+	SEQ_printf(m, "%9lld.%06ld %9lld.%06ld %9lld.%06ld %9lld.%06ld",
+		SPLIT_NS(schedstat_val_or_zero(p->stats.wait_sum)),
+		SPLIT_NS(p->se.sum_exec_runtime),
+		SPLIT_NS(schedstat_val_or_zero(p->stats.sum_sleep_runtime)),
+		SPLIT_NS(schedstat_val_or_zero(p->stats.sum_block_runtime)));
+
+#ifdef CONFIG_NUMA_BALANCING
+	SEQ_printf(m, " %d %d", task_node(p), task_numa_group_id(p));
+#endif
+#ifdef CONFIG_CGROUP_SCHED
+	SEQ_printf_task_group_path(m, task_group(p), " %s")
+#endif
+
+	SEQ_printf(m, "\n");
+}
+
+static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
+{
+	struct task_struct *g, *p;
+
+	SEQ_printf(m, "\n");
+	SEQ_printf(m, "runnable tasks:\n");
+	SEQ_printf(m, " S            task   PID         tree-key  switches  prio"
+		   "     wait-time             sum-exec        sum-sleep\n");
+	SEQ_printf(m, "-------------------------------------------------------"
+		   "------------------------------------------------------\n");
+
+	rcu_read_lock();
+	for_each_process_thread(g, p) {
+		if (task_cpu(p) != rq_cpu)
+			continue;
+
+		print_task(m, rq, p);
+	}
+	rcu_read_unlock();
+}
+
+void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
+{
+	s64 MIN_vruntime = -1, min_vruntime, max_vruntime = -1,
+		spread, rq0_min_vruntime, spread0;
+	struct rq *rq = cpu_rq(cpu);
+	struct sched_entity *last;
+	unsigned long flags;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	SEQ_printf(m, "\n");
+	SEQ_printf_task_group_path(m, cfs_rq->tg, "cfs_rq[%d]:%s\n", cpu);
+#else
+	SEQ_printf(m, "\n");
+	SEQ_printf(m, "cfs_rq[%d]:\n", cpu);
+#endif
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "exec_clock",
+			SPLIT_NS(cfs_rq->exec_clock));
+
+	raw_spin_rq_lock_irqsave(rq, flags);
+	if (rb_first_cached(&cfs_rq->tasks_timeline))
+		MIN_vruntime = (__pick_first_entity(cfs_rq))->vruntime;
+	last = __pick_last_entity(cfs_rq);
+	if (last)
+		max_vruntime = last->vruntime;
+	min_vruntime = cfs_rq->min_vruntime;
+	rq0_min_vruntime = cpu_rq(0)->cfs.min_vruntime;
+	raw_spin_rq_unlock_irqrestore(rq, flags);
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "MIN_vruntime",
+			SPLIT_NS(MIN_vruntime));
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "min_vruntime",
+			SPLIT_NS(min_vruntime));
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "max_vruntime",
+			SPLIT_NS(max_vruntime));
+	spread = max_vruntime - MIN_vruntime;
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread",
+			SPLIT_NS(spread));
+	spread0 = min_vruntime - rq0_min_vruntime;
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread0",
+			SPLIT_NS(spread0));
+	SEQ_printf(m, "  .%-30s: %d\n", "nr_spread_over",
+			cfs_rq->nr_spread_over);
+	SEQ_printf(m, "  .%-30s: %d\n", "nr_running", cfs_rq->nr_running);
+	SEQ_printf(m, "  .%-30s: %d\n", "h_nr_running", cfs_rq->h_nr_running);
+	SEQ_printf(m, "  .%-30s: %d\n", "idle_nr_running",
+			cfs_rq->idle_nr_running);
+	SEQ_printf(m, "  .%-30s: %d\n", "idle_h_nr_running",
+			cfs_rq->idle_h_nr_running);
+	SEQ_printf(m, "  .%-30s: %ld\n", "load", cfs_rq->load.weight);
+#ifdef CONFIG_SMP
+	SEQ_printf(m, "  .%-30s: %lu\n", "load_avg",
+			cfs_rq->avg.load_avg);
+	SEQ_printf(m, "  .%-30s: %lu\n", "runnable_avg",
+			cfs_rq->avg.runnable_avg);
+	SEQ_printf(m, "  .%-30s: %lu\n", "util_avg",
+			cfs_rq->avg.util_avg);
+	SEQ_printf(m, "  .%-30s: %u\n", "util_est_enqueued",
+			cfs_rq->avg.util_est.enqueued);
+	SEQ_printf(m, "  .%-30s: %ld\n", "removed.load_avg",
+			cfs_rq->removed.load_avg);
+	SEQ_printf(m, "  .%-30s: %ld\n", "removed.util_avg",
+			cfs_rq->removed.util_avg);
+	SEQ_printf(m, "  .%-30s: %ld\n", "removed.runnable_avg",
+			cfs_rq->removed.runnable_avg);
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	SEQ_printf(m, "  .%-30s: %lu\n", "tg_load_avg_contrib",
+			cfs_rq->tg_load_avg_contrib);
+	SEQ_printf(m, "  .%-30s: %ld\n", "tg_load_avg",
+			atomic_long_read(&cfs_rq->tg->load_avg));
+#endif
+#endif
+#ifdef CONFIG_CFS_BANDWIDTH
+	SEQ_printf(m, "  .%-30s: %d\n", "throttled",
+			cfs_rq->throttled);
+	SEQ_printf(m, "  .%-30s: %d\n", "throttle_count",
+			cfs_rq->throttle_count);
+#endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	print_cfs_group_stats(m, cpu, cfs_rq->tg);
+#endif
+}
+
+void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq)
+{
+#ifdef CONFIG_RT_GROUP_SCHED
+	SEQ_printf(m, "\n");
+	SEQ_printf_task_group_path(m, rt_rq->tg, "rt_rq[%d]:%s\n", cpu);
+#else
+	SEQ_printf(m, "\n");
+	SEQ_printf(m, "rt_rq[%d]:\n", cpu);
+#endif
+
+#define P(x) \
+	SEQ_printf(m, "  .%-30s: %Ld\n", #x, (long long)(rt_rq->x))
+#define PU(x) \
+	SEQ_printf(m, "  .%-30s: %lu\n", #x, (unsigned long)(rt_rq->x))
+#define PN(x) \
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rt_rq->x))
+
+	PU(rt_nr_running);
+#ifdef CONFIG_SMP
+	PU(rt_nr_migratory);
+#endif
+	P(rt_throttled);
+	PN(rt_time);
+	PN(rt_runtime);
+
+#undef PN
+#undef PU
+#undef P
+}
+
+void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq)
+{
+	struct dl_bw *dl_bw;
+
+	SEQ_printf(m, "\n");
+	SEQ_printf(m, "dl_rq[%d]:\n", cpu);
+
+#define PU(x) \
+	SEQ_printf(m, "  .%-30s: %lu\n", #x, (unsigned long)(dl_rq->x))
+
+	PU(dl_nr_running);
+#ifdef CONFIG_SMP
+	PU(dl_nr_migratory);
+	dl_bw = &cpu_rq(cpu)->rd->dl_bw;
+#else
+	dl_bw = &dl_rq->dl_bw;
+#endif
+	SEQ_printf(m, "  .%-30s: %lld\n", "dl_bw->bw", dl_bw->bw);
+	SEQ_printf(m, "  .%-30s: %lld\n", "dl_bw->total_bw", dl_bw->total_bw);
+
+#undef PU
+}
+
+static void print_cpu(struct seq_file *m, int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+#ifdef CONFIG_X86
+	{
+		unsigned int freq = cpu_khz ? : 1;
+
+		SEQ_printf(m, "cpu#%d, %u.%03u MHz\n",
+			   cpu, freq / 1000, (freq % 1000));
+	}
+#else
+	SEQ_printf(m, "cpu#%d\n", cpu);
+#endif
+
+#define P(x)								\
+do {									\
+	if (sizeof(rq->x) == 4)						\
+		SEQ_printf(m, "  .%-30s: %ld\n", #x, (long)(rq->x));	\
+	else								\
+		SEQ_printf(m, "  .%-30s: %Ld\n", #x, (long long)(rq->x));\
+} while (0)
+
+#define PN(x) \
+	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rq->x))
+
+	P(nr_running);
+	P(nr_switches);
+	P(nr_uninterruptible);
+	PN(next_balance);
+	SEQ_printf(m, "  .%-30s: %ld\n", "curr->pid", (long)(task_pid_nr(rq->curr)));
+	PN(clock);
+	PN(clock_task);
+#undef P
+#undef PN
+
+#ifdef CONFIG_SMP
+#define P64(n) SEQ_printf(m, "  .%-30s: %Ld\n", #n, rq->n);
+	P64(avg_idle);
+	P64(max_idle_balance_cost);
+#undef P64
+#endif
+
+#define P(n) SEQ_printf(m, "  .%-30s: %d\n", #n, schedstat_val(rq->n));
+	if (schedstat_enabled()) {
+		P(yld_count);
+		P(sched_count);
+		P(sched_goidle);
+		P(ttwu_count);
+		P(ttwu_local);
+	}
+#undef P
+
+	print_cfs_stats(m, cpu);
+	print_rt_stats(m, cpu);
+	print_dl_stats(m, cpu);
+
+	print_rq(m, rq, cpu);
+	SEQ_printf(m, "\n");
+}
+
+static const char *sched_tunable_scaling_names[] = {
+	"none",
+	"logarithmic",
+	"linear"
+};
+
+static void sched_debug_header(struct seq_file *m)
+{
+	u64 ktime, sched_clk, cpu_clk;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	ktime = ktime_to_ns(ktime_get());
+	sched_clk = sched_clock();
+	cpu_clk = local_clock();
+	local_irq_restore(flags);
+
+	SEQ_printf(m, "Sched Debug Version: v0.11, %s %.*s\n",
+		init_utsname()->release,
+		(int)strcspn(init_utsname()->version, " "),
+		init_utsname()->version);
+
+#define P(x) \
+	SEQ_printf(m, "%-40s: %Ld\n", #x, (long long)(x))
+#define PN(x) \
+	SEQ_printf(m, "%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
+	PN(ktime);
+	PN(sched_clk);
+	PN(cpu_clk);
+	P(jiffies);
+#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
+	P(sched_clock_stable());
+#endif
+#undef PN
+#undef P
+
+	SEQ_printf(m, "\n");
+	SEQ_printf(m, "sysctl_sched\n");
+
+#define P(x) \
+	SEQ_printf(m, "  .%-40s: %Ld\n", #x, (long long)(x))
+#define PN(x) \
+	SEQ_printf(m, "  .%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
+	PN(sysctl_sched_latency);
+	PN(sysctl_sched_min_granularity);
+	PN(sysctl_sched_idle_min_granularity);
+	PN(sysctl_sched_wakeup_granularity);
+	P(sysctl_sched_child_runs_first);
+	P(sysctl_sched_features);
+#undef PN
+#undef P
+
+	SEQ_printf(m, "  .%-40s: %d (%s)\n",
+		"sysctl_sched_tunable_scaling",
+		sysctl_sched_tunable_scaling,
+		sched_tunable_scaling_names[sysctl_sched_tunable_scaling]);
+	SEQ_printf(m, "\n");
+}
+
+static int sched_debug_show(struct seq_file *m, void *v)
+{
+	int cpu = (unsigned long)(v - 2);
+
+	if (cpu != -1)
+		print_cpu(m, cpu);
+	else
+		sched_debug_header(m);
+
+	return 0;
+}
+
+void sysrq_sched_debug_show(void)
+{
+	int cpu;
+
+	sched_debug_header(NULL);
+	for_each_online_cpu(cpu) {
+		/*
+		 * Need to reset softlockup watchdogs on all CPUs, because
+		 * another CPU might be blocked waiting for us to process
+		 * an IPI or stop_machine.
+		 */
+		touch_nmi_watchdog();
+		touch_all_softlockup_watchdogs();
+		print_cpu(NULL, cpu);
+	}
+}
+
+/*
+ * This iterator needs some explanation.
+ * It returns 1 for the header position.
+ * This means 2 is CPU 0.
+ * In a hotplugged system some CPUs, including CPU 0, may be missing so we have
+ * to use cpumask_* to iterate over the CPUs.
+ */
+static void *sched_debug_start(struct seq_file *file, loff_t *offset)
+{
+	unsigned long n = *offset;
+
+	if (n == 0)
+		return (void *) 1;
+
+	n--;
+
+	if (n > 0)
+		n = cpumask_next(n - 1, cpu_online_mask);
+	else
+		n = cpumask_first(cpu_online_mask);
+
+	*offset = n + 1;
+
+	if (n < nr_cpu_ids)
+		return (void *)(unsigned long)(n + 2);
+
+	return NULL;
+}
+
+static void *sched_debug_next(struct seq_file *file, void *data, loff_t *offset)
+{
+	(*offset)++;
+	return sched_debug_start(file, offset);
+}
+
+static void sched_debug_stop(struct seq_file *file, void *data)
+{
+}
+
+static const struct seq_operations sched_debug_sops = {
+	.start		= sched_debug_start,
+	.next		= sched_debug_next,
+	.stop		= sched_debug_stop,
+	.show		= sched_debug_show,
+};
+
+#define __PS(S, F) SEQ_printf(m, "%-45s:%21Ld\n", S, (long long)(F))
+#define __P(F) __PS(#F, F)
+#define   P(F) __PS(#F, p->F)
+#define   PM(F, M) __PS(#F, p->F & (M))
+#define __PSN(S, F) SEQ_printf(m, "%-45s:%14Ld.%06ld\n", S, SPLIT_NS((long long)(F)))
+#define __PN(F) __PSN(#F, F)
+#define   PN(F) __PSN(#F, p->F)
+
+
+#ifdef CONFIG_NUMA_BALANCING
+void print_numa_stats(struct seq_file *m, int node, unsigned long tsf,
+		unsigned long tpf, unsigned long gsf, unsigned long gpf)
+{
+	SEQ_printf(m, "numa_faults node=%d ", node);
+	SEQ_printf(m, "task_private=%lu task_shared=%lu ", tpf, tsf);
+	SEQ_printf(m, "group_private=%lu group_shared=%lu\n", gpf, gsf);
+}
+#endif
+
+
+static void sched_show_numa(struct task_struct *p, struct seq_file *m)
+{
+#ifdef CONFIG_NUMA_BALANCING
+	if (p->mm)
+		P(mm->numa_scan_seq);
+
+	P(numa_pages_migrated);
+	P(numa_preferred_nid);
+	P(total_numa_faults);
+	SEQ_printf(m, "current_node=%d, numa_group_id=%d\n",
+			task_node(p), task_numa_group_id(p));
+	show_numa_stats(p, m);
+#endif
+}
+
+void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
+						  struct seq_file *m)
+{
+	unsigned long nr_switches;
+
+	SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr_ns(p, ns),
+						get_nr_threads(p));
+	SEQ_printf(m,
+		"---------------------------------------------------------"
+		"----------\n");
+
+#define P_SCHEDSTAT(F)  __PS(#F, schedstat_val(p->stats.F))
+#define PN_SCHEDSTAT(F) __PSN(#F, schedstat_val(p->stats.F))
+
+	PN(se.exec_start);
+	PN(se.vruntime);
+	PN(se.sum_exec_runtime);
+
+	nr_switches = p->nvcsw + p->nivcsw;
+
+	P(se.nr_migrations);
+
+	if (schedstat_enabled()) {
+		u64 avg_atom, avg_per_cpu;
+
+		PN_SCHEDSTAT(sum_sleep_runtime);
+		PN_SCHEDSTAT(sum_block_runtime);
+		PN_SCHEDSTAT(wait_start);
+		PN_SCHEDSTAT(sleep_start);
+		PN_SCHEDSTAT(block_start);
+		PN_SCHEDSTAT(sleep_max);
+		PN_SCHEDSTAT(block_max);
+		PN_SCHEDSTAT(exec_max);
+		PN_SCHEDSTAT(slice_max);
+		PN_SCHEDSTAT(wait_max);
+		PN_SCHEDSTAT(wait_sum);
+		P_SCHEDSTAT(wait_count);
+		PN_SCHEDSTAT(iowait_sum);
+		P_SCHEDSTAT(iowait_count);
+		P_SCHEDSTAT(nr_migrations_cold);
+		P_SCHEDSTAT(nr_failed_migrations_affine);
+		P_SCHEDSTAT(nr_failed_migrations_running);
+		P_SCHEDSTAT(nr_failed_migrations_hot);
+		P_SCHEDSTAT(nr_forced_migrations);
+		P_SCHEDSTAT(nr_wakeups);
+		P_SCHEDSTAT(nr_wakeups_sync);
+		P_SCHEDSTAT(nr_wakeups_migrate);
+		P_SCHEDSTAT(nr_wakeups_local);
+		P_SCHEDSTAT(nr_wakeups_remote);
+		P_SCHEDSTAT(nr_wakeups_affine);
+		P_SCHEDSTAT(nr_wakeups_affine_attempts);
+		P_SCHEDSTAT(nr_wakeups_passive);
+		P_SCHEDSTAT(nr_wakeups_idle);
+
+		avg_atom = p->se.sum_exec_runtime;
+		if (nr_switches)
+			avg_atom = div64_ul(avg_atom, nr_switches);
+		else
+			avg_atom = -1LL;
+
+		avg_per_cpu = p->se.sum_exec_runtime;
+		if (p->se.nr_migrations) {
+			avg_per_cpu = div64_u64(avg_per_cpu,
+						p->se.nr_migrations);
+		} else {
+			avg_per_cpu = -1LL;
+		}
+
+		__PN(avg_atom);
+		__PN(avg_per_cpu);
+
+#ifdef CONFIG_SCHED_CORE
+		PN_SCHEDSTAT(core_forceidle_sum);
+#endif
+	}
+
+	__P(nr_switches);
+	__PS("nr_voluntary_switches", p->nvcsw);
+	__PS("nr_involuntary_switches", p->nivcsw);
+
+	P(se.load.weight);
+#ifdef CONFIG_SMP
+	P(se.avg.load_sum);
+	P(se.avg.runnable_sum);
+	P(se.avg.util_sum);
+	P(se.avg.load_avg);
+	P(se.avg.runnable_avg);
+	P(se.avg.util_avg);
+	P(se.avg.last_update_time);
+	P(se.avg.util_est.ewma);
+	PM(se.avg.util_est.enqueued, ~UTIL_AVG_UNCHANGED);
+#endif
+#ifdef CONFIG_UCLAMP_TASK
+	__PS("uclamp.min", p->uclamp_req[UCLAMP_MIN].value);
+	__PS("uclamp.max", p->uclamp_req[UCLAMP_MAX].value);
+	__PS("effective uclamp.min", uclamp_eff_value(p, UCLAMP_MIN));
+	__PS("effective uclamp.max", uclamp_eff_value(p, UCLAMP_MAX));
+#endif
+	P(policy);
+	P(prio);
+	if (task_has_dl_policy(p)) {
+		P(dl.runtime);
+		P(dl.deadline);
+	}
+#undef PN_SCHEDSTAT
+#undef P_SCHEDSTAT
+
+	{
+		unsigned int this_cpu = raw_smp_processor_id();
+		u64 t0, t1;
+
+		t0 = cpu_clock(this_cpu);
+		t1 = cpu_clock(this_cpu);
+		__PS("clock-delta", t1-t0);
+	}
+
+	sched_show_numa(p, m);
+}
+
+void proc_sched_set_task(struct task_struct *p)
+{
+#ifdef CONFIG_SCHEDSTATS
+	memset(&p->stats, 0, sizeof(p->stats));
+#endif
+}
+
+void resched_latency_warn(int cpu, u64 latency)
+{
+	static DEFINE_RATELIMIT_STATE(latency_check_ratelimit, 60 * 60 * HZ, 1);
+
+	WARN(__ratelimit(&latency_check_ratelimit),
+	     "sched: CPU %d need_resched set for > %llu ns (%d ticks) "
+	     "without schedule\n",
+	     cpu, latency, cpu_rq(cpu)->ticks_without_resched);
+}
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
new file mode 100644
index 000000000..2558ab903
--- /dev/null
+++ b/kernel/sched/fair.c
@@ -0,0 +1,12506 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Completely Fair Scheduling (CFS) Class (SCHED_NORMAL/SCHED_BATCH)
+ *
+ *  Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ *  Interactivity improvements by Mike Galbraith
+ *  (C) 2007 Mike Galbraith <efault@gmx.de>
+ *
+ *  Various enhancements by Dmitry Adamushko.
+ *  (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com>
+ *
+ *  Group scheduling enhancements by Srivatsa Vaddagiri
+ *  Copyright IBM Corporation, 2007
+ *  Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
+ *
+ *  Scaled math optimizations by Thomas Gleixner
+ *  Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de>
+ *
+ *  Adaptive scheduling granularity, math enhancements by Peter Zijlstra
+ *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
+ */
+#include <linux/energy_model.h>
+#include <linux/mmap_lock.h>
+#include <linux/hugetlb_inline.h>
+#include <linux/jiffies.h>
+#include <linux/mm_api.h>
+#include <linux/highmem.h>
+#include <linux/spinlock_api.h>
+#include <linux/cpumask_api.h>
+#include <linux/lockdep_api.h>
+#include <linux/softirq.h>
+#include <linux/refcount_api.h>
+#include <linux/topology.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/cond_resched.h>
+#include <linux/sched/cputime.h>
+#include <linux/sched/isolation.h>
+#include <linux/sched/nohz.h>
+
+#include <linux/cpuidle.h>
+#include <linux/interrupt.h>
+#include <linux/memory-tiers.h>
+#include <linux/mempolicy.h>
+#include <linux/mutex_api.h>
+#include <linux/profile.h>
+#include <linux/psi.h>
+#include <linux/ratelimit.h>
+#include <linux/task_work.h>
+
+#include <asm/switch_to.h>
+
+#include <linux/sched/cond_resched.h>
+
+#include "sched.h"
+#include "stats.h"
+#include "autogroup.h"
+
+/*
+ * Targeted preemption latency for CPU-bound tasks:
+ *
+ * NOTE: this latency value is not the same as the concept of
+ * 'timeslice length' - timeslices in CFS are of variable length
+ * and have no persistent notion like in traditional, time-slice
+ * based scheduling concepts.
+ *
+ * (to see the precise effective timeslice length of your workload,
+ *  run vmstat and monitor the context-switches (cs) field)
+ *
+ * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds)
+ */
+unsigned int sysctl_sched_latency			= 6000000ULL;
+static unsigned int normalized_sysctl_sched_latency	= 6000000ULL;
+
+/*
+ * The initial- and re-scaling of tunables is configurable
+ *
+ * Options are:
+ *
+ *   SCHED_TUNABLESCALING_NONE - unscaled, always *1
+ *   SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus)
+ *   SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus
+ *
+ * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus))
+ */
+unsigned int sysctl_sched_tunable_scaling = SCHED_TUNABLESCALING_LOG;
+
+/*
+ * Minimal preemption granularity for CPU-bound tasks:
+ *
+ * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds)
+ */
+unsigned int sysctl_sched_min_granularity			= 750000ULL;
+static unsigned int normalized_sysctl_sched_min_granularity	= 750000ULL;
+
+/*
+ * Minimal preemption granularity for CPU-bound SCHED_IDLE tasks.
+ * Applies only when SCHED_IDLE tasks compete with normal tasks.
+ *
+ * (default: 0.75 msec)
+ */
+unsigned int sysctl_sched_idle_min_granularity			= 750000ULL;
+
+/*
+ * This value is kept at sysctl_sched_latency/sysctl_sched_min_granularity
+ */
+static unsigned int sched_nr_latency = 8;
+
+/*
+ * After fork, child runs first. If set to 0 (default) then
+ * parent will (try to) run first.
+ */
+unsigned int sysctl_sched_child_runs_first __read_mostly;
+
+/*
+ * SCHED_OTHER wake-up granularity.
+ *
+ * This option delays the preemption effects of decoupled workloads
+ * and reduces their over-scheduling. Synchronous workloads will still
+ * have immediate wakeup/sleep latencies.
+ *
+ * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds)
+ */
+unsigned int sysctl_sched_wakeup_granularity			= 1000000UL;
+static unsigned int normalized_sysctl_sched_wakeup_granularity	= 1000000UL;
+
+const_debug unsigned int sysctl_sched_migration_cost	= 500000UL;
+
+int sched_thermal_decay_shift;
+static int __init setup_sched_thermal_decay_shift(char *str)
+{
+	int _shift = 0;
+
+	if (kstrtoint(str, 0, &_shift))
+		pr_warn("Unable to set scheduler thermal pressure decay shift parameter\n");
+
+	sched_thermal_decay_shift = clamp(_shift, 0, 10);
+	return 1;
+}
+__setup("sched_thermal_decay_shift=", setup_sched_thermal_decay_shift);
+
+#ifdef CONFIG_SMP
+/*
+ * For asym packing, by default the lower numbered CPU has higher priority.
+ */
+int __weak arch_asym_cpu_priority(int cpu)
+{
+	return -cpu;
+}
+
+/*
+ * The margin used when comparing utilization with CPU capacity.
+ *
+ * (default: ~20%)
+ */
+#define fits_capacity(cap, max)	((cap) * 1280 < (max) * 1024)
+
+/*
+ * The margin used when comparing CPU capacities.
+ * is 'cap1' noticeably greater than 'cap2'
+ *
+ * (default: ~5%)
+ */
+#define capacity_greater(cap1, cap2) ((cap1) * 1024 > (cap2) * 1078)
+#endif
+
+#ifdef CONFIG_CFS_BANDWIDTH
+/*
+ * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool
+ * each time a cfs_rq requests quota.
+ *
+ * Note: in the case that the slice exceeds the runtime remaining (either due
+ * to consumption or the quota being specified to be smaller than the slice)
+ * we will always only issue the remaining available time.
+ *
+ * (default: 5 msec, units: microseconds)
+ */
+static unsigned int sysctl_sched_cfs_bandwidth_slice		= 5000UL;
+#endif
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table sched_fair_sysctls[] = {
+	{
+		.procname       = "sched_child_runs_first",
+		.data           = &sysctl_sched_child_runs_first,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec,
+	},
+#ifdef CONFIG_CFS_BANDWIDTH
+	{
+		.procname       = "sched_cfs_bandwidth_slice_us",
+		.data           = &sysctl_sched_cfs_bandwidth_slice,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec_minmax,
+		.extra1         = SYSCTL_ONE,
+	},
+#endif
+	{}
+};
+
+static int __init sched_fair_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_fair_sysctls);
+	return 0;
+}
+late_initcall(sched_fair_sysctl_init);
+#endif
+
+static inline void update_load_add(struct load_weight *lw, unsigned long inc)
+{
+	lw->weight += inc;
+	lw->inv_weight = 0;
+}
+
+static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
+{
+	lw->weight -= dec;
+	lw->inv_weight = 0;
+}
+
+static inline void update_load_set(struct load_weight *lw, unsigned long w)
+{
+	lw->weight = w;
+	lw->inv_weight = 0;
+}
+
+/*
+ * Increase the granularity value when there are more CPUs,
+ * because with more CPUs the 'effective latency' as visible
+ * to users decreases. But the relationship is not linear,
+ * so pick a second-best guess by going with the log2 of the
+ * number of CPUs.
+ *
+ * This idea comes from the SD scheduler of Con Kolivas:
+ */
+static unsigned int get_update_sysctl_factor(void)
+{
+	unsigned int cpus = min_t(unsigned int, num_online_cpus(), 8);
+	unsigned int factor;
+
+	switch (sysctl_sched_tunable_scaling) {
+	case SCHED_TUNABLESCALING_NONE:
+		factor = 1;
+		break;
+	case SCHED_TUNABLESCALING_LINEAR:
+		factor = cpus;
+		break;
+	case SCHED_TUNABLESCALING_LOG:
+	default:
+		factor = 1 + ilog2(cpus);
+		break;
+	}
+
+	return factor;
+}
+
+static void update_sysctl(void)
+{
+	unsigned int factor = get_update_sysctl_factor();
+
+#define SET_SYSCTL(name) \
+	(sysctl_##name = (factor) * normalized_sysctl_##name)
+	SET_SYSCTL(sched_min_granularity);
+	SET_SYSCTL(sched_latency);
+	SET_SYSCTL(sched_wakeup_granularity);
+#undef SET_SYSCTL
+}
+
+void __init sched_init_granularity(void)
+{
+	update_sysctl();
+}
+
+#define WMULT_CONST	(~0U)
+#define WMULT_SHIFT	32
+
+static void __update_inv_weight(struct load_weight *lw)
+{
+	unsigned long w;
+
+	if (likely(lw->inv_weight))
+		return;
+
+	w = scale_load_down(lw->weight);
+
+	if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST))
+		lw->inv_weight = 1;
+	else if (unlikely(!w))
+		lw->inv_weight = WMULT_CONST;
+	else
+		lw->inv_weight = WMULT_CONST / w;
+}
+
+/*
+ * delta_exec * weight / lw.weight
+ *   OR
+ * (delta_exec * (weight * lw->inv_weight)) >> WMULT_SHIFT
+ *
+ * Either weight := NICE_0_LOAD and lw \e sched_prio_to_wmult[], in which case
+ * we're guaranteed shift stays positive because inv_weight is guaranteed to
+ * fit 32 bits, and NICE_0_LOAD gives another 10 bits; therefore shift >= 22.
+ *
+ * Or, weight =< lw.weight (because lw.weight is the runqueue weight), thus
+ * weight/lw.weight <= 1, and therefore our shift will also be positive.
+ */
+static u64 __calc_delta(u64 delta_exec, unsigned long weight, struct load_weight *lw)
+{
+	u64 fact = scale_load_down(weight);
+	u32 fact_hi = (u32)(fact >> 32);
+	int shift = WMULT_SHIFT;
+	int fs;
+
+	__update_inv_weight(lw);
+
+	if (unlikely(fact_hi)) {
+		fs = fls(fact_hi);
+		shift -= fs;
+		fact >>= fs;
+	}
+
+	fact = mul_u32_u32(fact, lw->inv_weight);
+
+	fact_hi = (u32)(fact >> 32);
+	if (fact_hi) {
+		fs = fls(fact_hi);
+		shift -= fs;
+		fact >>= fs;
+	}
+
+	return mul_u64_u32_shr(delta_exec, fact, shift);
+}
+
+
+const struct sched_class fair_sched_class;
+
+/**************************************************************
+ * CFS operations on generic schedulable entities:
+ */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+/* Walk up scheduling entities hierarchy */
+#define for_each_sched_entity(se) \
+		for (; se; se = se->parent)
+
+static inline bool list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	struct rq *rq = rq_of(cfs_rq);
+	int cpu = cpu_of(rq);
+
+	if (cfs_rq->on_list)
+		return rq->tmp_alone_branch == &rq->leaf_cfs_rq_list;
+
+	cfs_rq->on_list = 1;
+
+	/*
+	 * Ensure we either appear before our parent (if already
+	 * enqueued) or force our parent to appear after us when it is
+	 * enqueued. The fact that we always enqueue bottom-up
+	 * reduces this to two cases and a special case for the root
+	 * cfs_rq. Furthermore, it also means that we will always reset
+	 * tmp_alone_branch either when the branch is connected
+	 * to a tree or when we reach the top of the tree
+	 */
+	if (cfs_rq->tg->parent &&
+	    cfs_rq->tg->parent->cfs_rq[cpu]->on_list) {
+		/*
+		 * If parent is already on the list, we add the child
+		 * just before. Thanks to circular linked property of
+		 * the list, this means to put the child at the tail
+		 * of the list that starts by parent.
+		 */
+		list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
+			&(cfs_rq->tg->parent->cfs_rq[cpu]->leaf_cfs_rq_list));
+		/*
+		 * The branch is now connected to its tree so we can
+		 * reset tmp_alone_branch to the beginning of the
+		 * list.
+		 */
+		rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
+		return true;
+	}
+
+	if (!cfs_rq->tg->parent) {
+		/*
+		 * cfs rq without parent should be put
+		 * at the tail of the list.
+		 */
+		list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
+			&rq->leaf_cfs_rq_list);
+		/*
+		 * We have reach the top of a tree so we can reset
+		 * tmp_alone_branch to the beginning of the list.
+		 */
+		rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
+		return true;
+	}
+
+	/*
+	 * The parent has not already been added so we want to
+	 * make sure that it will be put after us.
+	 * tmp_alone_branch points to the begin of the branch
+	 * where we will add parent.
+	 */
+	list_add_rcu(&cfs_rq->leaf_cfs_rq_list, rq->tmp_alone_branch);
+	/*
+	 * update tmp_alone_branch to points to the new begin
+	 * of the branch
+	 */
+	rq->tmp_alone_branch = &cfs_rq->leaf_cfs_rq_list;
+	return false;
+}
+
+static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	if (cfs_rq->on_list) {
+		struct rq *rq = rq_of(cfs_rq);
+
+		/*
+		 * With cfs_rq being unthrottled/throttled during an enqueue,
+		 * it can happen the tmp_alone_branch points the a leaf that
+		 * we finally want to del. In this case, tmp_alone_branch moves
+		 * to the prev element but it will point to rq->leaf_cfs_rq_list
+		 * at the end of the enqueue.
+		 */
+		if (rq->tmp_alone_branch == &cfs_rq->leaf_cfs_rq_list)
+			rq->tmp_alone_branch = cfs_rq->leaf_cfs_rq_list.prev;
+
+		list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
+		cfs_rq->on_list = 0;
+	}
+}
+
+static inline void assert_list_leaf_cfs_rq(struct rq *rq)
+{
+	SCHED_WARN_ON(rq->tmp_alone_branch != &rq->leaf_cfs_rq_list);
+}
+
+/* Iterate thr' all leaf cfs_rq's on a runqueue */
+#define for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos)			\
+	list_for_each_entry_safe(cfs_rq, pos, &rq->leaf_cfs_rq_list,	\
+				 leaf_cfs_rq_list)
+
+/* Do the two (enqueued) entities belong to the same group ? */
+static inline struct cfs_rq *
+is_same_group(struct sched_entity *se, struct sched_entity *pse)
+{
+	if (se->cfs_rq == pse->cfs_rq)
+		return se->cfs_rq;
+
+	return NULL;
+}
+
+static inline struct sched_entity *parent_entity(struct sched_entity *se)
+{
+	return se->parent;
+}
+
+static void
+find_matching_se(struct sched_entity **se, struct sched_entity **pse)
+{
+	int se_depth, pse_depth;
+
+	/*
+	 * preemption test can be made between sibling entities who are in the
+	 * same cfs_rq i.e who have a common parent. Walk up the hierarchy of
+	 * both tasks until we find their ancestors who are siblings of common
+	 * parent.
+	 */
+
+	/* First walk up until both entities are at same depth */
+	se_depth = (*se)->depth;
+	pse_depth = (*pse)->depth;
+
+	while (se_depth > pse_depth) {
+		se_depth--;
+		*se = parent_entity(*se);
+	}
+
+	while (pse_depth > se_depth) {
+		pse_depth--;
+		*pse = parent_entity(*pse);
+	}
+
+	while (!is_same_group(*se, *pse)) {
+		*se = parent_entity(*se);
+		*pse = parent_entity(*pse);
+	}
+}
+
+static int tg_is_idle(struct task_group *tg)
+{
+	return tg->idle > 0;
+}
+
+static int cfs_rq_is_idle(struct cfs_rq *cfs_rq)
+{
+	return cfs_rq->idle > 0;
+}
+
+static int se_is_idle(struct sched_entity *se)
+{
+	if (entity_is_task(se))
+		return task_has_idle_policy(task_of(se));
+	return cfs_rq_is_idle(group_cfs_rq(se));
+}
+
+#else	/* !CONFIG_FAIR_GROUP_SCHED */
+
+#define for_each_sched_entity(se) \
+		for (; se; se = NULL)
+
+static inline bool list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	return true;
+}
+
+static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
+{
+}
+
+static inline void assert_list_leaf_cfs_rq(struct rq *rq)
+{
+}
+
+#define for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos)	\
+		for (cfs_rq = &rq->cfs, pos = NULL; cfs_rq; cfs_rq = pos)
+
+static inline struct sched_entity *parent_entity(struct sched_entity *se)
+{
+	return NULL;
+}
+
+static inline void
+find_matching_se(struct sched_entity **se, struct sched_entity **pse)
+{
+}
+
+static inline int tg_is_idle(struct task_group *tg)
+{
+	return 0;
+}
+
+static int cfs_rq_is_idle(struct cfs_rq *cfs_rq)
+{
+	return 0;
+}
+
+static int se_is_idle(struct sched_entity *se)
+{
+	return 0;
+}
+
+#endif	/* CONFIG_FAIR_GROUP_SCHED */
+
+static __always_inline
+void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec);
+
+/**************************************************************
+ * Scheduling class tree data structure manipulation methods:
+ */
+
+static inline u64 max_vruntime(u64 max_vruntime, u64 vruntime)
+{
+	s64 delta = (s64)(vruntime - max_vruntime);
+	if (delta > 0)
+		max_vruntime = vruntime;
+
+	return max_vruntime;
+}
+
+static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime)
+{
+	s64 delta = (s64)(vruntime - min_vruntime);
+	if (delta < 0)
+		min_vruntime = vruntime;
+
+	return min_vruntime;
+}
+
+static inline bool entity_before(struct sched_entity *a,
+				struct sched_entity *b)
+{
+	return (s64)(a->vruntime - b->vruntime) < 0;
+}
+
+#define __node_2_se(node) \
+	rb_entry((node), struct sched_entity, run_node)
+
+static void update_min_vruntime(struct cfs_rq *cfs_rq)
+{
+	struct sched_entity *curr = cfs_rq->curr;
+	struct rb_node *leftmost = rb_first_cached(&cfs_rq->tasks_timeline);
+
+	u64 vruntime = cfs_rq->min_vruntime;
+
+	if (curr) {
+		if (curr->on_rq)
+			vruntime = curr->vruntime;
+		else
+			curr = NULL;
+	}
+
+	if (leftmost) { /* non-empty tree */
+		struct sched_entity *se = __node_2_se(leftmost);
+
+		if (!curr)
+			vruntime = se->vruntime;
+		else
+			vruntime = min_vruntime(vruntime, se->vruntime);
+	}
+
+	/* ensure we never gain time by being placed backwards. */
+	u64_u32_store(cfs_rq->min_vruntime,
+		      max_vruntime(cfs_rq->min_vruntime, vruntime));
+}
+
+static inline bool __entity_less(struct rb_node *a, const struct rb_node *b)
+{
+	return entity_before(__node_2_se(a), __node_2_se(b));
+}
+
+/*
+ * Enqueue an entity into the rb-tree:
+ */
+static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	rb_add_cached(&se->run_node, &cfs_rq->tasks_timeline, __entity_less);
+}
+
+static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	rb_erase_cached(&se->run_node, &cfs_rq->tasks_timeline);
+}
+
+struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq)
+{
+	struct rb_node *left = rb_first_cached(&cfs_rq->tasks_timeline);
+
+	if (!left)
+		return NULL;
+
+	return __node_2_se(left);
+}
+
+static struct sched_entity *__pick_next_entity(struct sched_entity *se)
+{
+	struct rb_node *next = rb_next(&se->run_node);
+
+	if (!next)
+		return NULL;
+
+	return __node_2_se(next);
+}
+
+#ifdef CONFIG_SCHED_DEBUG
+struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
+{
+	struct rb_node *last = rb_last(&cfs_rq->tasks_timeline.rb_root);
+
+	if (!last)
+		return NULL;
+
+	return __node_2_se(last);
+}
+
+/**************************************************************
+ * Scheduling class statistics methods:
+ */
+
+int sched_update_scaling(void)
+{
+	unsigned int factor = get_update_sysctl_factor();
+
+	sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency,
+					sysctl_sched_min_granularity);
+
+#define WRT_SYSCTL(name) \
+	(normalized_sysctl_##name = sysctl_##name / (factor))
+	WRT_SYSCTL(sched_min_granularity);
+	WRT_SYSCTL(sched_latency);
+	WRT_SYSCTL(sched_wakeup_granularity);
+#undef WRT_SYSCTL
+
+	return 0;
+}
+#endif
+
+/*
+ * delta /= w
+ */
+static inline u64 calc_delta_fair(u64 delta, struct sched_entity *se)
+{
+	if (unlikely(se->load.weight != NICE_0_LOAD))
+		delta = __calc_delta(delta, NICE_0_LOAD, &se->load);
+
+	return delta;
+}
+
+/*
+ * The idea is to set a period in which each task runs once.
+ *
+ * When there are too many tasks (sched_nr_latency) we have to stretch
+ * this period because otherwise the slices get too small.
+ *
+ * p = (nr <= nl) ? l : l*nr/nl
+ */
+static u64 __sched_period(unsigned long nr_running)
+{
+	if (unlikely(nr_running > sched_nr_latency))
+		return nr_running * sysctl_sched_min_granularity;
+	else
+		return sysctl_sched_latency;
+}
+
+static bool sched_idle_cfs_rq(struct cfs_rq *cfs_rq);
+
+/*
+ * We calculate the wall-time slice from the period by taking a part
+ * proportional to the weight.
+ *
+ * s = p*P[w/rw]
+ */
+static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	unsigned int nr_running = cfs_rq->nr_running;
+	struct sched_entity *init_se = se;
+	unsigned int min_gran;
+	u64 slice;
+
+	if (sched_feat(ALT_PERIOD))
+		nr_running = rq_of(cfs_rq)->cfs.h_nr_running;
+
+	slice = __sched_period(nr_running + !se->on_rq);
+
+	for_each_sched_entity(se) {
+		struct load_weight *load;
+		struct load_weight lw;
+		struct cfs_rq *qcfs_rq;
+
+		qcfs_rq = cfs_rq_of(se);
+		load = &qcfs_rq->load;
+
+		if (unlikely(!se->on_rq)) {
+			lw = qcfs_rq->load;
+
+			update_load_add(&lw, se->load.weight);
+			load = &lw;
+		}
+		slice = __calc_delta(slice, se->load.weight, load);
+	}
+
+	if (sched_feat(BASE_SLICE)) {
+		if (se_is_idle(init_se) && !sched_idle_cfs_rq(cfs_rq))
+			min_gran = sysctl_sched_idle_min_granularity;
+		else
+			min_gran = sysctl_sched_min_granularity;
+
+		slice = max_t(u64, slice, min_gran);
+	}
+
+	return slice;
+}
+
+/*
+ * We calculate the vruntime slice of a to-be-inserted task.
+ *
+ * vs = s/w
+ */
+static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	return calc_delta_fair(sched_slice(cfs_rq, se), se);
+}
+
+#include "pelt.h"
+#ifdef CONFIG_SMP
+
+static int select_idle_sibling(struct task_struct *p, int prev_cpu, int cpu);
+static unsigned long task_h_load(struct task_struct *p);
+static unsigned long capacity_of(int cpu);
+
+/* Give new sched_entity start runnable values to heavy its load in infant time */
+void init_entity_runnable_average(struct sched_entity *se)
+{
+	struct sched_avg *sa = &se->avg;
+
+	memset(sa, 0, sizeof(*sa));
+
+	/*
+	 * Tasks are initialized with full load to be seen as heavy tasks until
+	 * they get a chance to stabilize to their real load level.
+	 * Group entities are initialized with zero load to reflect the fact that
+	 * nothing has been attached to the task group yet.
+	 */
+	if (entity_is_task(se))
+		sa->load_avg = scale_load_down(se->load.weight);
+
+	/* when this task enqueue'ed, it will contribute to its cfs_rq's load_avg */
+}
+
+/*
+ * With new tasks being created, their initial util_avgs are extrapolated
+ * based on the cfs_rq's current util_avg:
+ *
+ *   util_avg = cfs_rq->util_avg / (cfs_rq->load_avg + 1) * se.load.weight
+ *
+ * However, in many cases, the above util_avg does not give a desired
+ * value. Moreover, the sum of the util_avgs may be divergent, such
+ * as when the series is a harmonic series.
+ *
+ * To solve this problem, we also cap the util_avg of successive tasks to
+ * only 1/2 of the left utilization budget:
+ *
+ *   util_avg_cap = (cpu_scale - cfs_rq->avg.util_avg) / 2^n
+ *
+ * where n denotes the nth task and cpu_scale the CPU capacity.
+ *
+ * For example, for a CPU with 1024 of capacity, a simplest series from
+ * the beginning would be like:
+ *
+ *  task  util_avg: 512, 256, 128,  64,  32,   16,    8, ...
+ * cfs_rq util_avg: 512, 768, 896, 960, 992, 1008, 1016, ...
+ *
+ * Finally, that extrapolated util_avg is clamped to the cap (util_avg_cap)
+ * if util_avg > util_avg_cap.
+ */
+void post_init_entity_util_avg(struct task_struct *p)
+{
+	struct sched_entity *se = &p->se;
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+	struct sched_avg *sa = &se->avg;
+	long cpu_scale = arch_scale_cpu_capacity(cpu_of(rq_of(cfs_rq)));
+	long cap = (long)(cpu_scale - cfs_rq->avg.util_avg) / 2;
+
+	if (p->sched_class != &fair_sched_class) {
+		/*
+		 * For !fair tasks do:
+		 *
+		update_cfs_rq_load_avg(now, cfs_rq);
+		attach_entity_load_avg(cfs_rq, se);
+		switched_from_fair(rq, p);
+		 *
+		 * such that the next switched_to_fair() has the
+		 * expected state.
+		 */
+		se->avg.last_update_time = cfs_rq_clock_pelt(cfs_rq);
+		return;
+	}
+
+	if (cap > 0) {
+		if (cfs_rq->avg.util_avg != 0) {
+			sa->util_avg  = cfs_rq->avg.util_avg * se->load.weight;
+			sa->util_avg /= (cfs_rq->avg.load_avg + 1);
+
+			if (sa->util_avg > cap)
+				sa->util_avg = cap;
+		} else {
+			sa->util_avg = cap;
+		}
+	}
+
+	sa->runnable_avg = sa->util_avg;
+}
+
+#else /* !CONFIG_SMP */
+void init_entity_runnable_average(struct sched_entity *se)
+{
+}
+void post_init_entity_util_avg(struct task_struct *p)
+{
+}
+static void update_tg_load_avg(struct cfs_rq *cfs_rq)
+{
+}
+#endif /* CONFIG_SMP */
+
+/*
+ * Update the current task's runtime statistics.
+ */
+static void update_curr(struct cfs_rq *cfs_rq)
+{
+	struct sched_entity *curr = cfs_rq->curr;
+	u64 now = rq_clock_task(rq_of(cfs_rq));
+	u64 delta_exec;
+
+	if (unlikely(!curr))
+		return;
+
+	delta_exec = now - curr->exec_start;
+	if (unlikely((s64)delta_exec <= 0))
+		return;
+
+	curr->exec_start = now;
+
+	if (schedstat_enabled()) {
+		struct sched_statistics *stats;
+
+		stats = __schedstats_from_se(curr);
+		__schedstat_set(stats->exec_max,
+				max(delta_exec, stats->exec_max));
+	}
+
+	curr->sum_exec_runtime += delta_exec;
+	schedstat_add(cfs_rq->exec_clock, delta_exec);
+
+	curr->vruntime += calc_delta_fair(delta_exec, curr);
+	update_min_vruntime(cfs_rq);
+
+	if (entity_is_task(curr)) {
+		struct task_struct *curtask = task_of(curr);
+
+		trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime);
+		cgroup_account_cputime(curtask, delta_exec);
+		account_group_exec_runtime(curtask, delta_exec);
+	}
+
+	account_cfs_rq_runtime(cfs_rq, delta_exec);
+}
+
+static void update_curr_fair(struct rq *rq)
+{
+	update_curr(cfs_rq_of(&rq->curr->se));
+}
+
+static inline void
+update_stats_wait_start_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	struct sched_statistics *stats;
+	struct task_struct *p = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	stats = __schedstats_from_se(se);
+
+	if (entity_is_task(se))
+		p = task_of(se);
+
+	__update_stats_wait_start(rq_of(cfs_rq), p, stats);
+}
+
+static inline void
+update_stats_wait_end_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	struct sched_statistics *stats;
+	struct task_struct *p = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	stats = __schedstats_from_se(se);
+
+	/*
+	 * When the sched_schedstat changes from 0 to 1, some sched se
+	 * maybe already in the runqueue, the se->statistics.wait_start
+	 * will be 0.So it will let the delta wrong. We need to avoid this
+	 * scenario.
+	 */
+	if (unlikely(!schedstat_val(stats->wait_start)))
+		return;
+
+	if (entity_is_task(se))
+		p = task_of(se);
+
+	__update_stats_wait_end(rq_of(cfs_rq), p, stats);
+}
+
+static inline void
+update_stats_enqueue_sleeper_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	struct sched_statistics *stats;
+	struct task_struct *tsk = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	stats = __schedstats_from_se(se);
+
+	if (entity_is_task(se))
+		tsk = task_of(se);
+
+	__update_stats_enqueue_sleeper(rq_of(cfs_rq), tsk, stats);
+}
+
+/*
+ * Task is being enqueued - update stats:
+ */
+static inline void
+update_stats_enqueue_fair(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+	if (!schedstat_enabled())
+		return;
+
+	/*
+	 * Are we enqueueing a waiting task? (for current tasks
+	 * a dequeue/enqueue event is a NOP)
+	 */
+	if (se != cfs_rq->curr)
+		update_stats_wait_start_fair(cfs_rq, se);
+
+	if (flags & ENQUEUE_WAKEUP)
+		update_stats_enqueue_sleeper_fair(cfs_rq, se);
+}
+
+static inline void
+update_stats_dequeue_fair(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+
+	if (!schedstat_enabled())
+		return;
+
+	/*
+	 * Mark the end of the wait period if dequeueing a
+	 * waiting task:
+	 */
+	if (se != cfs_rq->curr)
+		update_stats_wait_end_fair(cfs_rq, se);
+
+	if ((flags & DEQUEUE_SLEEP) && entity_is_task(se)) {
+		struct task_struct *tsk = task_of(se);
+		unsigned int state;
+
+		/* XXX racy against TTWU */
+		state = READ_ONCE(tsk->__state);
+		if (state & TASK_INTERRUPTIBLE)
+			__schedstat_set(tsk->stats.sleep_start,
+				      rq_clock(rq_of(cfs_rq)));
+		if (state & TASK_UNINTERRUPTIBLE)
+			__schedstat_set(tsk->stats.block_start,
+				      rq_clock(rq_of(cfs_rq)));
+	}
+}
+
+/*
+ * We are picking a new current task - update its stats:
+ */
+static inline void
+update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	/*
+	 * We are starting a new run period:
+	 */
+	se->exec_start = rq_clock_task(rq_of(cfs_rq));
+}
+
+/**************************************************
+ * Scheduling class queueing methods:
+ */
+
+#ifdef CONFIG_NUMA
+#define NUMA_IMBALANCE_MIN 2
+
+static inline long
+adjust_numa_imbalance(int imbalance, int dst_running, int imb_numa_nr)
+{
+	/*
+	 * Allow a NUMA imbalance if busy CPUs is less than the maximum
+	 * threshold. Above this threshold, individual tasks may be contending
+	 * for both memory bandwidth and any shared HT resources.  This is an
+	 * approximation as the number of running tasks may not be related to
+	 * the number of busy CPUs due to sched_setaffinity.
+	 */
+	if (dst_running > imb_numa_nr)
+		return imbalance;
+
+	/*
+	 * Allow a small imbalance based on a simple pair of communicating
+	 * tasks that remain local when the destination is lightly loaded.
+	 */
+	if (imbalance <= NUMA_IMBALANCE_MIN)
+		return 0;
+
+	return imbalance;
+}
+#endif /* CONFIG_NUMA */
+
+#ifdef CONFIG_NUMA_BALANCING
+/*
+ * Approximate time to scan a full NUMA task in ms. The task scan period is
+ * calculated based on the tasks virtual memory size and
+ * numa_balancing_scan_size.
+ */
+unsigned int sysctl_numa_balancing_scan_period_min = 1000;
+unsigned int sysctl_numa_balancing_scan_period_max = 60000;
+
+/* Portion of address space to scan in MB */
+unsigned int sysctl_numa_balancing_scan_size = 256;
+
+/* Scan @scan_size MB every @scan_period after an initial @scan_delay in ms */
+unsigned int sysctl_numa_balancing_scan_delay = 1000;
+
+/* The page with hint page fault latency < threshold in ms is considered hot */
+unsigned int sysctl_numa_balancing_hot_threshold = MSEC_PER_SEC;
+
+/* Restrict the NUMA promotion throughput (MB/s) for each target node. */
+unsigned int sysctl_numa_balancing_promote_rate_limit = 65536;
+
+struct numa_group {
+	refcount_t refcount;
+
+	spinlock_t lock; /* nr_tasks, tasks */
+	int nr_tasks;
+	pid_t gid;
+	int active_nodes;
+
+	struct rcu_head rcu;
+	unsigned long total_faults;
+	unsigned long max_faults_cpu;
+	/*
+	 * faults[] array is split into two regions: faults_mem and faults_cpu.
+	 *
+	 * Faults_cpu is used to decide whether memory should move
+	 * towards the CPU. As a consequence, these stats are weighted
+	 * more by CPU use than by memory faults.
+	 */
+	unsigned long faults[];
+};
+
+/*
+ * For functions that can be called in multiple contexts that permit reading
+ * ->numa_group (see struct task_struct for locking rules).
+ */
+static struct numa_group *deref_task_numa_group(struct task_struct *p)
+{
+	return rcu_dereference_check(p->numa_group, p == current ||
+		(lockdep_is_held(__rq_lockp(task_rq(p))) && !READ_ONCE(p->on_cpu)));
+}
+
+static struct numa_group *deref_curr_numa_group(struct task_struct *p)
+{
+	return rcu_dereference_protected(p->numa_group, p == current);
+}
+
+static inline unsigned long group_faults_priv(struct numa_group *ng);
+static inline unsigned long group_faults_shared(struct numa_group *ng);
+
+static unsigned int task_nr_scan_windows(struct task_struct *p)
+{
+	unsigned long rss = 0;
+	unsigned long nr_scan_pages;
+
+	/*
+	 * Calculations based on RSS as non-present and empty pages are skipped
+	 * by the PTE scanner and NUMA hinting faults should be trapped based
+	 * on resident pages
+	 */
+	nr_scan_pages = sysctl_numa_balancing_scan_size << (20 - PAGE_SHIFT);
+	rss = get_mm_rss(p->mm);
+	if (!rss)
+		rss = nr_scan_pages;
+
+	rss = round_up(rss, nr_scan_pages);
+	return rss / nr_scan_pages;
+}
+
+/* For sanity's sake, never scan more PTEs than MAX_SCAN_WINDOW MB/sec. */
+#define MAX_SCAN_WINDOW 2560
+
+static unsigned int task_scan_min(struct task_struct *p)
+{
+	unsigned int scan_size = READ_ONCE(sysctl_numa_balancing_scan_size);
+	unsigned int scan, floor;
+	unsigned int windows = 1;
+
+	if (scan_size < MAX_SCAN_WINDOW)
+		windows = MAX_SCAN_WINDOW / scan_size;
+	floor = 1000 / windows;
+
+	scan = sysctl_numa_balancing_scan_period_min / task_nr_scan_windows(p);
+	return max_t(unsigned int, floor, scan);
+}
+
+static unsigned int task_scan_start(struct task_struct *p)
+{
+	unsigned long smin = task_scan_min(p);
+	unsigned long period = smin;
+	struct numa_group *ng;
+
+	/* Scale the maximum scan period with the amount of shared memory. */
+	rcu_read_lock();
+	ng = rcu_dereference(p->numa_group);
+	if (ng) {
+		unsigned long shared = group_faults_shared(ng);
+		unsigned long private = group_faults_priv(ng);
+
+		period *= refcount_read(&ng->refcount);
+		period *= shared + 1;
+		period /= private + shared + 1;
+	}
+	rcu_read_unlock();
+
+	return max(smin, period);
+}
+
+static unsigned int task_scan_max(struct task_struct *p)
+{
+	unsigned long smin = task_scan_min(p);
+	unsigned long smax;
+	struct numa_group *ng;
+
+	/* Watch for min being lower than max due to floor calculations */
+	smax = sysctl_numa_balancing_scan_period_max / task_nr_scan_windows(p);
+
+	/* Scale the maximum scan period with the amount of shared memory. */
+	ng = deref_curr_numa_group(p);
+	if (ng) {
+		unsigned long shared = group_faults_shared(ng);
+		unsigned long private = group_faults_priv(ng);
+		unsigned long period = smax;
+
+		period *= refcount_read(&ng->refcount);
+		period *= shared + 1;
+		period /= private + shared + 1;
+
+		smax = max(smax, period);
+	}
+
+	return max(smin, smax);
+}
+
+static void account_numa_enqueue(struct rq *rq, struct task_struct *p)
+{
+	rq->nr_numa_running += (p->numa_preferred_nid != NUMA_NO_NODE);
+	rq->nr_preferred_running += (p->numa_preferred_nid == task_node(p));
+}
+
+static void account_numa_dequeue(struct rq *rq, struct task_struct *p)
+{
+	rq->nr_numa_running -= (p->numa_preferred_nid != NUMA_NO_NODE);
+	rq->nr_preferred_running -= (p->numa_preferred_nid == task_node(p));
+}
+
+/* Shared or private faults. */
+#define NR_NUMA_HINT_FAULT_TYPES 2
+
+/* Memory and CPU locality */
+#define NR_NUMA_HINT_FAULT_STATS (NR_NUMA_HINT_FAULT_TYPES * 2)
+
+/* Averaged statistics, and temporary buffers. */
+#define NR_NUMA_HINT_FAULT_BUCKETS (NR_NUMA_HINT_FAULT_STATS * 2)
+
+pid_t task_numa_group_id(struct task_struct *p)
+{
+	struct numa_group *ng;
+	pid_t gid = 0;
+
+	rcu_read_lock();
+	ng = rcu_dereference(p->numa_group);
+	if (ng)
+		gid = ng->gid;
+	rcu_read_unlock();
+
+	return gid;
+}
+
+/*
+ * The averaged statistics, shared & private, memory & CPU,
+ * occupy the first half of the array. The second half of the
+ * array is for current counters, which are averaged into the
+ * first set by task_numa_placement.
+ */
+static inline int task_faults_idx(enum numa_faults_stats s, int nid, int priv)
+{
+	return NR_NUMA_HINT_FAULT_TYPES * (s * nr_node_ids + nid) + priv;
+}
+
+static inline unsigned long task_faults(struct task_struct *p, int nid)
+{
+	if (!p->numa_faults)
+		return 0;
+
+	return p->numa_faults[task_faults_idx(NUMA_MEM, nid, 0)] +
+		p->numa_faults[task_faults_idx(NUMA_MEM, nid, 1)];
+}
+
+static inline unsigned long group_faults(struct task_struct *p, int nid)
+{
+	struct numa_group *ng = deref_task_numa_group(p);
+
+	if (!ng)
+		return 0;
+
+	return ng->faults[task_faults_idx(NUMA_MEM, nid, 0)] +
+		ng->faults[task_faults_idx(NUMA_MEM, nid, 1)];
+}
+
+static inline unsigned long group_faults_cpu(struct numa_group *group, int nid)
+{
+	return group->faults[task_faults_idx(NUMA_CPU, nid, 0)] +
+		group->faults[task_faults_idx(NUMA_CPU, nid, 1)];
+}
+
+static inline unsigned long group_faults_priv(struct numa_group *ng)
+{
+	unsigned long faults = 0;
+	int node;
+
+	for_each_online_node(node) {
+		faults += ng->faults[task_faults_idx(NUMA_MEM, node, 1)];
+	}
+
+	return faults;
+}
+
+static inline unsigned long group_faults_shared(struct numa_group *ng)
+{
+	unsigned long faults = 0;
+	int node;
+
+	for_each_online_node(node) {
+		faults += ng->faults[task_faults_idx(NUMA_MEM, node, 0)];
+	}
+
+	return faults;
+}
+
+/*
+ * A node triggering more than 1/3 as many NUMA faults as the maximum is
+ * considered part of a numa group's pseudo-interleaving set. Migrations
+ * between these nodes are slowed down, to allow things to settle down.
+ */
+#define ACTIVE_NODE_FRACTION 3
+
+static bool numa_is_active_node(int nid, struct numa_group *ng)
+{
+	return group_faults_cpu(ng, nid) * ACTIVE_NODE_FRACTION > ng->max_faults_cpu;
+}
+
+/* Handle placement on systems where not all nodes are directly connected. */
+static unsigned long score_nearby_nodes(struct task_struct *p, int nid,
+					int lim_dist, bool task)
+{
+	unsigned long score = 0;
+	int node, max_dist;
+
+	/*
+	 * All nodes are directly connected, and the same distance
+	 * from each other. No need for fancy placement algorithms.
+	 */
+	if (sched_numa_topology_type == NUMA_DIRECT)
+		return 0;
+
+	/* sched_max_numa_distance may be changed in parallel. */
+	max_dist = READ_ONCE(sched_max_numa_distance);
+	/*
+	 * This code is called for each node, introducing N^2 complexity,
+	 * which should be ok given the number of nodes rarely exceeds 8.
+	 */
+	for_each_online_node(node) {
+		unsigned long faults;
+		int dist = node_distance(nid, node);
+
+		/*
+		 * The furthest away nodes in the system are not interesting
+		 * for placement; nid was already counted.
+		 */
+		if (dist >= max_dist || node == nid)
+			continue;
+
+		/*
+		 * On systems with a backplane NUMA topology, compare groups
+		 * of nodes, and move tasks towards the group with the most
+		 * memory accesses. When comparing two nodes at distance
+		 * "hoplimit", only nodes closer by than "hoplimit" are part
+		 * of each group. Skip other nodes.
+		 */
+		if (sched_numa_topology_type == NUMA_BACKPLANE && dist >= lim_dist)
+			continue;
+
+		/* Add up the faults from nearby nodes. */
+		if (task)
+			faults = task_faults(p, node);
+		else
+			faults = group_faults(p, node);
+
+		/*
+		 * On systems with a glueless mesh NUMA topology, there are
+		 * no fixed "groups of nodes". Instead, nodes that are not
+		 * directly connected bounce traffic through intermediate
+		 * nodes; a numa_group can occupy any set of nodes.
+		 * The further away a node is, the less the faults count.
+		 * This seems to result in good task placement.
+		 */
+		if (sched_numa_topology_type == NUMA_GLUELESS_MESH) {
+			faults *= (max_dist - dist);
+			faults /= (max_dist - LOCAL_DISTANCE);
+		}
+
+		score += faults;
+	}
+
+	return score;
+}
+
+/*
+ * These return the fraction of accesses done by a particular task, or
+ * task group, on a particular numa node.  The group weight is given a
+ * larger multiplier, in order to group tasks together that are almost
+ * evenly spread out between numa nodes.
+ */
+static inline unsigned long task_weight(struct task_struct *p, int nid,
+					int dist)
+{
+	unsigned long faults, total_faults;
+
+	if (!p->numa_faults)
+		return 0;
+
+	total_faults = p->total_numa_faults;
+
+	if (!total_faults)
+		return 0;
+
+	faults = task_faults(p, nid);
+	faults += score_nearby_nodes(p, nid, dist, true);
+
+	return 1000 * faults / total_faults;
+}
+
+static inline unsigned long group_weight(struct task_struct *p, int nid,
+					 int dist)
+{
+	struct numa_group *ng = deref_task_numa_group(p);
+	unsigned long faults, total_faults;
+
+	if (!ng)
+		return 0;
+
+	total_faults = ng->total_faults;
+
+	if (!total_faults)
+		return 0;
+
+	faults = group_faults(p, nid);
+	faults += score_nearby_nodes(p, nid, dist, false);
+
+	return 1000 * faults / total_faults;
+}
+
+/*
+ * If memory tiering mode is enabled, cpupid of slow memory page is
+ * used to record scan time instead of CPU and PID.  When tiering mode
+ * is disabled at run time, the scan time (in cpupid) will be
+ * interpreted as CPU and PID.  So CPU needs to be checked to avoid to
+ * access out of array bound.
+ */
+static inline bool cpupid_valid(int cpupid)
+{
+	return cpupid_to_cpu(cpupid) < nr_cpu_ids;
+}
+
+/*
+ * For memory tiering mode, if there are enough free pages (more than
+ * enough watermark defined here) in fast memory node, to take full
+ * advantage of fast memory capacity, all recently accessed slow
+ * memory pages will be migrated to fast memory node without
+ * considering hot threshold.
+ */
+static bool pgdat_free_space_enough(struct pglist_data *pgdat)
+{
+	int z;
+	unsigned long enough_wmark;
+
+	enough_wmark = max(1UL * 1024 * 1024 * 1024 >> PAGE_SHIFT,
+			   pgdat->node_present_pages >> 4);
+	for (z = pgdat->nr_zones - 1; z >= 0; z--) {
+		struct zone *zone = pgdat->node_zones + z;
+
+		if (!populated_zone(zone))
+			continue;
+
+		if (zone_watermark_ok(zone, 0,
+				      wmark_pages(zone, WMARK_PROMO) + enough_wmark,
+				      ZONE_MOVABLE, 0))
+			return true;
+	}
+	return false;
+}
+
+/*
+ * For memory tiering mode, when page tables are scanned, the scan
+ * time will be recorded in struct page in addition to make page
+ * PROT_NONE for slow memory page.  So when the page is accessed, in
+ * hint page fault handler, the hint page fault latency is calculated
+ * via,
+ *
+ *	hint page fault latency = hint page fault time - scan time
+ *
+ * The smaller the hint page fault latency, the higher the possibility
+ * for the page to be hot.
+ */
+static int numa_hint_fault_latency(struct page *page)
+{
+	int last_time, time;
+
+	time = jiffies_to_msecs(jiffies);
+	last_time = xchg_page_access_time(page, time);
+
+	return (time - last_time) & PAGE_ACCESS_TIME_MASK;
+}
+
+/*
+ * For memory tiering mode, too high promotion/demotion throughput may
+ * hurt application latency.  So we provide a mechanism to rate limit
+ * the number of pages that are tried to be promoted.
+ */
+static bool numa_promotion_rate_limit(struct pglist_data *pgdat,
+				      unsigned long rate_limit, int nr)
+{
+	unsigned long nr_cand;
+	unsigned int now, start;
+
+	now = jiffies_to_msecs(jiffies);
+	mod_node_page_state(pgdat, PGPROMOTE_CANDIDATE, nr);
+	nr_cand = node_page_state(pgdat, PGPROMOTE_CANDIDATE);
+	start = pgdat->nbp_rl_start;
+	if (now - start > MSEC_PER_SEC &&
+	    cmpxchg(&pgdat->nbp_rl_start, start, now) == start)
+		pgdat->nbp_rl_nr_cand = nr_cand;
+	if (nr_cand - pgdat->nbp_rl_nr_cand >= rate_limit)
+		return true;
+	return false;
+}
+
+#define NUMA_MIGRATION_ADJUST_STEPS	16
+
+static void numa_promotion_adjust_threshold(struct pglist_data *pgdat,
+					    unsigned long rate_limit,
+					    unsigned int ref_th)
+{
+	unsigned int now, start, th_period, unit_th, th;
+	unsigned long nr_cand, ref_cand, diff_cand;
+
+	now = jiffies_to_msecs(jiffies);
+	th_period = sysctl_numa_balancing_scan_period_max;
+	start = pgdat->nbp_th_start;
+	if (now - start > th_period &&
+	    cmpxchg(&pgdat->nbp_th_start, start, now) == start) {
+		ref_cand = rate_limit *
+			sysctl_numa_balancing_scan_period_max / MSEC_PER_SEC;
+		nr_cand = node_page_state(pgdat, PGPROMOTE_CANDIDATE);
+		diff_cand = nr_cand - pgdat->nbp_th_nr_cand;
+		unit_th = ref_th * 2 / NUMA_MIGRATION_ADJUST_STEPS;
+		th = pgdat->nbp_threshold ? : ref_th;
+		if (diff_cand > ref_cand * 11 / 10)
+			th = max(th - unit_th, unit_th);
+		else if (diff_cand < ref_cand * 9 / 10)
+			th = min(th + unit_th, ref_th * 2);
+		pgdat->nbp_th_nr_cand = nr_cand;
+		pgdat->nbp_threshold = th;
+	}
+}
+
+bool should_numa_migrate_memory(struct task_struct *p, struct page * page,
+				int src_nid, int dst_cpu)
+{
+	struct numa_group *ng = deref_curr_numa_group(p);
+	int dst_nid = cpu_to_node(dst_cpu);
+	int last_cpupid, this_cpupid;
+
+	/*
+	 * The pages in slow memory node should be migrated according
+	 * to hot/cold instead of private/shared.
+	 */
+	if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
+	    !node_is_toptier(src_nid)) {
+		struct pglist_data *pgdat;
+		unsigned long rate_limit;
+		unsigned int latency, th, def_th;
+
+		pgdat = NODE_DATA(dst_nid);
+		if (pgdat_free_space_enough(pgdat)) {
+			/* workload changed, reset hot threshold */
+			pgdat->nbp_threshold = 0;
+			return true;
+		}
+
+		def_th = sysctl_numa_balancing_hot_threshold;
+		rate_limit = sysctl_numa_balancing_promote_rate_limit << \
+			(20 - PAGE_SHIFT);
+		numa_promotion_adjust_threshold(pgdat, rate_limit, def_th);
+
+		th = pgdat->nbp_threshold ? : def_th;
+		latency = numa_hint_fault_latency(page);
+		if (latency >= th)
+			return false;
+
+		return !numa_promotion_rate_limit(pgdat, rate_limit,
+						  thp_nr_pages(page));
+	}
+
+	this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid);
+	last_cpupid = page_cpupid_xchg_last(page, this_cpupid);
+
+	if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) &&
+	    !node_is_toptier(src_nid) && !cpupid_valid(last_cpupid))
+		return false;
+
+	/*
+	 * Allow first faults or private faults to migrate immediately early in
+	 * the lifetime of a task. The magic number 4 is based on waiting for
+	 * two full passes of the "multi-stage node selection" test that is
+	 * executed below.
+	 */
+	if ((p->numa_preferred_nid == NUMA_NO_NODE || p->numa_scan_seq <= 4) &&
+	    (cpupid_pid_unset(last_cpupid) || cpupid_match_pid(p, last_cpupid)))
+		return true;
+
+	/*
+	 * Multi-stage node selection is used in conjunction with a periodic
+	 * migration fault to build a temporal task<->page relation. By using
+	 * a two-stage filter we remove short/unlikely relations.
+	 *
+	 * Using P(p) ~ n_p / n_t as per frequentist probability, we can equate
+	 * a task's usage of a particular page (n_p) per total usage of this
+	 * page (n_t) (in a given time-span) to a probability.
+	 *
+	 * Our periodic faults will sample this probability and getting the
+	 * same result twice in a row, given these samples are fully
+	 * independent, is then given by P(n)^2, provided our sample period
+	 * is sufficiently short compared to the usage pattern.
+	 *
+	 * This quadric squishes small probabilities, making it less likely we
+	 * act on an unlikely task<->page relation.
+	 */
+	if (!cpupid_pid_unset(last_cpupid) &&
+				cpupid_to_nid(last_cpupid) != dst_nid)
+		return false;
+
+	/* Always allow migrate on private faults */
+	if (cpupid_match_pid(p, last_cpupid))
+		return true;
+
+	/* A shared fault, but p->numa_group has not been set up yet. */
+	if (!ng)
+		return true;
+
+	/*
+	 * Destination node is much more heavily used than the source
+	 * node? Allow migration.
+	 */
+	if (group_faults_cpu(ng, dst_nid) > group_faults_cpu(ng, src_nid) *
+					ACTIVE_NODE_FRACTION)
+		return true;
+
+	/*
+	 * Distribute memory according to CPU & memory use on each node,
+	 * with 3/4 hysteresis to avoid unnecessary memory migrations:
+	 *
+	 * faults_cpu(dst)   3   faults_cpu(src)
+	 * --------------- * - > ---------------
+	 * faults_mem(dst)   4   faults_mem(src)
+	 */
+	return group_faults_cpu(ng, dst_nid) * group_faults(p, src_nid) * 3 >
+	       group_faults_cpu(ng, src_nid) * group_faults(p, dst_nid) * 4;
+}
+
+/*
+ * 'numa_type' describes the node at the moment of load balancing.
+ */
+enum numa_type {
+	/* The node has spare capacity that can be used to run more tasks.  */
+	node_has_spare = 0,
+	/*
+	 * The node is fully used and the tasks don't compete for more CPU
+	 * cycles. Nevertheless, some tasks might wait before running.
+	 */
+	node_fully_busy,
+	/*
+	 * The node is overloaded and can't provide expected CPU cycles to all
+	 * tasks.
+	 */
+	node_overloaded
+};
+
+/* Cached statistics for all CPUs within a node */
+struct numa_stats {
+	unsigned long load;
+	unsigned long runnable;
+	unsigned long util;
+	/* Total compute capacity of CPUs on a node */
+	unsigned long compute_capacity;
+	unsigned int nr_running;
+	unsigned int weight;
+	enum numa_type node_type;
+	int idle_cpu;
+};
+
+static inline bool is_core_idle(int cpu)
+{
+#ifdef CONFIG_SCHED_SMT
+	int sibling;
+
+	for_each_cpu(sibling, cpu_smt_mask(cpu)) {
+		if (cpu == sibling)
+			continue;
+
+		if (!idle_cpu(sibling))
+			return false;
+	}
+#endif
+
+	return true;
+}
+
+struct task_numa_env {
+	struct task_struct *p;
+
+	int src_cpu, src_nid;
+	int dst_cpu, dst_nid;
+	int imb_numa_nr;
+
+	struct numa_stats src_stats, dst_stats;
+
+	int imbalance_pct;
+	int dist;
+
+	struct task_struct *best_task;
+	long best_imp;
+	int best_cpu;
+};
+
+static unsigned long cpu_load(struct rq *rq);
+static unsigned long cpu_runnable(struct rq *rq);
+
+static inline enum
+numa_type numa_classify(unsigned int imbalance_pct,
+			 struct numa_stats *ns)
+{
+	if ((ns->nr_running > ns->weight) &&
+	    (((ns->compute_capacity * 100) < (ns->util * imbalance_pct)) ||
+	     ((ns->compute_capacity * imbalance_pct) < (ns->runnable * 100))))
+		return node_overloaded;
+
+	if ((ns->nr_running < ns->weight) ||
+	    (((ns->compute_capacity * 100) > (ns->util * imbalance_pct)) &&
+	     ((ns->compute_capacity * imbalance_pct) > (ns->runnable * 100))))
+		return node_has_spare;
+
+	return node_fully_busy;
+}
+
+#ifdef CONFIG_SCHED_SMT
+/* Forward declarations of select_idle_sibling helpers */
+static inline bool test_idle_cores(int cpu);
+static inline int numa_idle_core(int idle_core, int cpu)
+{
+	if (!static_branch_likely(&sched_smt_present) ||
+	    idle_core >= 0 || !test_idle_cores(cpu))
+		return idle_core;
+
+	/*
+	 * Prefer cores instead of packing HT siblings
+	 * and triggering future load balancing.
+	 */
+	if (is_core_idle(cpu))
+		idle_core = cpu;
+
+	return idle_core;
+}
+#else
+static inline int numa_idle_core(int idle_core, int cpu)
+{
+	return idle_core;
+}
+#endif
+
+/*
+ * Gather all necessary information to make NUMA balancing placement
+ * decisions that are compatible with standard load balancer. This
+ * borrows code and logic from update_sg_lb_stats but sharing a
+ * common implementation is impractical.
+ */
+static void update_numa_stats(struct task_numa_env *env,
+			      struct numa_stats *ns, int nid,
+			      bool find_idle)
+{
+	int cpu, idle_core = -1;
+
+	memset(ns, 0, sizeof(*ns));
+	ns->idle_cpu = -1;
+
+	rcu_read_lock();
+	for_each_cpu(cpu, cpumask_of_node(nid)) {
+		struct rq *rq = cpu_rq(cpu);
+
+		ns->load += cpu_load(rq);
+		ns->runnable += cpu_runnable(rq);
+		ns->util += cpu_util_cfs(cpu);
+		ns->nr_running += rq->cfs.h_nr_running;
+		ns->compute_capacity += capacity_of(cpu);
+
+		if (find_idle && !rq->nr_running && idle_cpu(cpu)) {
+			if (READ_ONCE(rq->numa_migrate_on) ||
+			    !cpumask_test_cpu(cpu, env->p->cpus_ptr))
+				continue;
+
+			if (ns->idle_cpu == -1)
+				ns->idle_cpu = cpu;
+
+			idle_core = numa_idle_core(idle_core, cpu);
+		}
+	}
+	rcu_read_unlock();
+
+	ns->weight = cpumask_weight(cpumask_of_node(nid));
+
+	ns->node_type = numa_classify(env->imbalance_pct, ns);
+
+	if (idle_core >= 0)
+		ns->idle_cpu = idle_core;
+}
+
+static void task_numa_assign(struct task_numa_env *env,
+			     struct task_struct *p, long imp)
+{
+	struct rq *rq = cpu_rq(env->dst_cpu);
+
+	/* Check if run-queue part of active NUMA balance. */
+	if (env->best_cpu != env->dst_cpu && xchg(&rq->numa_migrate_on, 1)) {
+		int cpu;
+		int start = env->dst_cpu;
+
+		/* Find alternative idle CPU. */
+		for_each_cpu_wrap(cpu, cpumask_of_node(env->dst_nid), start) {
+			if (cpu == env->best_cpu || !idle_cpu(cpu) ||
+			    !cpumask_test_cpu(cpu, env->p->cpus_ptr)) {
+				continue;
+			}
+
+			env->dst_cpu = cpu;
+			rq = cpu_rq(env->dst_cpu);
+			if (!xchg(&rq->numa_migrate_on, 1))
+				goto assign;
+		}
+
+		/* Failed to find an alternative idle CPU */
+		return;
+	}
+
+assign:
+	/*
+	 * Clear previous best_cpu/rq numa-migrate flag, since task now
+	 * found a better CPU to move/swap.
+	 */
+	if (env->best_cpu != -1 && env->best_cpu != env->dst_cpu) {
+		rq = cpu_rq(env->best_cpu);
+		WRITE_ONCE(rq->numa_migrate_on, 0);
+	}
+
+	if (env->best_task)
+		put_task_struct(env->best_task);
+	if (p)
+		get_task_struct(p);
+
+	env->best_task = p;
+	env->best_imp = imp;
+	env->best_cpu = env->dst_cpu;
+}
+
+static bool load_too_imbalanced(long src_load, long dst_load,
+				struct task_numa_env *env)
+{
+	long imb, old_imb;
+	long orig_src_load, orig_dst_load;
+	long src_capacity, dst_capacity;
+
+	/*
+	 * The load is corrected for the CPU capacity available on each node.
+	 *
+	 * src_load        dst_load
+	 * ------------ vs ---------
+	 * src_capacity    dst_capacity
+	 */
+	src_capacity = env->src_stats.compute_capacity;
+	dst_capacity = env->dst_stats.compute_capacity;
+
+	imb = abs(dst_load * src_capacity - src_load * dst_capacity);
+
+	orig_src_load = env->src_stats.load;
+	orig_dst_load = env->dst_stats.load;
+
+	old_imb = abs(orig_dst_load * src_capacity - orig_src_load * dst_capacity);
+
+	/* Would this change make things worse? */
+	return (imb > old_imb);
+}
+
+/*
+ * Maximum NUMA importance can be 1998 (2*999);
+ * SMALLIMP @ 30 would be close to 1998/64.
+ * Used to deter task migration.
+ */
+#define SMALLIMP	30
+
+/*
+ * This checks if the overall compute and NUMA accesses of the system would
+ * be improved if the source tasks was migrated to the target dst_cpu taking
+ * into account that it might be best if task running on the dst_cpu should
+ * be exchanged with the source task
+ */
+static bool task_numa_compare(struct task_numa_env *env,
+			      long taskimp, long groupimp, bool maymove)
+{
+	struct numa_group *cur_ng, *p_ng = deref_curr_numa_group(env->p);
+	struct rq *dst_rq = cpu_rq(env->dst_cpu);
+	long imp = p_ng ? groupimp : taskimp;
+	struct task_struct *cur;
+	long src_load, dst_load;
+	int dist = env->dist;
+	long moveimp = imp;
+	long load;
+	bool stopsearch = false;
+
+	if (READ_ONCE(dst_rq->numa_migrate_on))
+		return false;
+
+	rcu_read_lock();
+	cur = rcu_dereference(dst_rq->curr);
+	if (cur && ((cur->flags & PF_EXITING) || is_idle_task(cur)))
+		cur = NULL;
+
+	/*
+	 * Because we have preemption enabled we can get migrated around and
+	 * end try selecting ourselves (current == env->p) as a swap candidate.
+	 */
+	if (cur == env->p) {
+		stopsearch = true;
+		goto unlock;
+	}
+
+	if (!cur) {
+		if (maymove && moveimp >= env->best_imp)
+			goto assign;
+		else
+			goto unlock;
+	}
+
+	/* Skip this swap candidate if cannot move to the source cpu. */
+	if (!cpumask_test_cpu(env->src_cpu, cur->cpus_ptr))
+		goto unlock;
+
+	/*
+	 * Skip this swap candidate if it is not moving to its preferred
+	 * node and the best task is.
+	 */
+	if (env->best_task &&
+	    env->best_task->numa_preferred_nid == env->src_nid &&
+	    cur->numa_preferred_nid != env->src_nid) {
+		goto unlock;
+	}
+
+	/*
+	 * "imp" is the fault differential for the source task between the
+	 * source and destination node. Calculate the total differential for
+	 * the source task and potential destination task. The more negative
+	 * the value is, the more remote accesses that would be expected to
+	 * be incurred if the tasks were swapped.
+	 *
+	 * If dst and source tasks are in the same NUMA group, or not
+	 * in any group then look only at task weights.
+	 */
+	cur_ng = rcu_dereference(cur->numa_group);
+	if (cur_ng == p_ng) {
+		/*
+		 * Do not swap within a group or between tasks that have
+		 * no group if there is spare capacity. Swapping does
+		 * not address the load imbalance and helps one task at
+		 * the cost of punishing another.
+		 */
+		if (env->dst_stats.node_type == node_has_spare)
+			goto unlock;
+
+		imp = taskimp + task_weight(cur, env->src_nid, dist) -
+		      task_weight(cur, env->dst_nid, dist);
+		/*
+		 * Add some hysteresis to prevent swapping the
+		 * tasks within a group over tiny differences.
+		 */
+		if (cur_ng)
+			imp -= imp / 16;
+	} else {
+		/*
+		 * Compare the group weights. If a task is all by itself
+		 * (not part of a group), use the task weight instead.
+		 */
+		if (cur_ng && p_ng)
+			imp += group_weight(cur, env->src_nid, dist) -
+			       group_weight(cur, env->dst_nid, dist);
+		else
+			imp += task_weight(cur, env->src_nid, dist) -
+			       task_weight(cur, env->dst_nid, dist);
+	}
+
+	/* Discourage picking a task already on its preferred node */
+	if (cur->numa_preferred_nid == env->dst_nid)
+		imp -= imp / 16;
+
+	/*
+	 * Encourage picking a task that moves to its preferred node.
+	 * This potentially makes imp larger than it's maximum of
+	 * 1998 (see SMALLIMP and task_weight for why) but in this
+	 * case, it does not matter.
+	 */
+	if (cur->numa_preferred_nid == env->src_nid)
+		imp += imp / 8;
+
+	if (maymove && moveimp > imp && moveimp > env->best_imp) {
+		imp = moveimp;
+		cur = NULL;
+		goto assign;
+	}
+
+	/*
+	 * Prefer swapping with a task moving to its preferred node over a
+	 * task that is not.
+	 */
+	if (env->best_task && cur->numa_preferred_nid == env->src_nid &&
+	    env->best_task->numa_preferred_nid != env->src_nid) {
+		goto assign;
+	}
+
+	/*
+	 * If the NUMA importance is less than SMALLIMP,
+	 * task migration might only result in ping pong
+	 * of tasks and also hurt performance due to cache
+	 * misses.
+	 */
+	if (imp < SMALLIMP || imp <= env->best_imp + SMALLIMP / 2)
+		goto unlock;
+
+	/*
+	 * In the overloaded case, try and keep the load balanced.
+	 */
+	load = task_h_load(env->p) - task_h_load(cur);
+	if (!load)
+		goto assign;
+
+	dst_load = env->dst_stats.load + load;
+	src_load = env->src_stats.load - load;
+
+	if (load_too_imbalanced(src_load, dst_load, env))
+		goto unlock;
+
+assign:
+	/* Evaluate an idle CPU for a task numa move. */
+	if (!cur) {
+		int cpu = env->dst_stats.idle_cpu;
+
+		/* Nothing cached so current CPU went idle since the search. */
+		if (cpu < 0)
+			cpu = env->dst_cpu;
+
+		/*
+		 * If the CPU is no longer truly idle and the previous best CPU
+		 * is, keep using it.
+		 */
+		if (!idle_cpu(cpu) && env->best_cpu >= 0 &&
+		    idle_cpu(env->best_cpu)) {
+			cpu = env->best_cpu;
+		}
+
+		env->dst_cpu = cpu;
+	}
+
+	task_numa_assign(env, cur, imp);
+
+	/*
+	 * If a move to idle is allowed because there is capacity or load
+	 * balance improves then stop the search. While a better swap
+	 * candidate may exist, a search is not free.
+	 */
+	if (maymove && !cur && env->best_cpu >= 0 && idle_cpu(env->best_cpu))
+		stopsearch = true;
+
+	/*
+	 * If a swap candidate must be identified and the current best task
+	 * moves its preferred node then stop the search.
+	 */
+	if (!maymove && env->best_task &&
+	    env->best_task->numa_preferred_nid == env->src_nid) {
+		stopsearch = true;
+	}
+unlock:
+	rcu_read_unlock();
+
+	return stopsearch;
+}
+
+static void task_numa_find_cpu(struct task_numa_env *env,
+				long taskimp, long groupimp)
+{
+	bool maymove = false;
+	int cpu;
+
+	/*
+	 * If dst node has spare capacity, then check if there is an
+	 * imbalance that would be overruled by the load balancer.
+	 */
+	if (env->dst_stats.node_type == node_has_spare) {
+		unsigned int imbalance;
+		int src_running, dst_running;
+
+		/*
+		 * Would movement cause an imbalance? Note that if src has
+		 * more running tasks that the imbalance is ignored as the
+		 * move improves the imbalance from the perspective of the
+		 * CPU load balancer.
+		 * */
+		src_running = env->src_stats.nr_running - 1;
+		dst_running = env->dst_stats.nr_running + 1;
+		imbalance = max(0, dst_running - src_running);
+		imbalance = adjust_numa_imbalance(imbalance, dst_running,
+						  env->imb_numa_nr);
+
+		/* Use idle CPU if there is no imbalance */
+		if (!imbalance) {
+			maymove = true;
+			if (env->dst_stats.idle_cpu >= 0) {
+				env->dst_cpu = env->dst_stats.idle_cpu;
+				task_numa_assign(env, NULL, 0);
+				return;
+			}
+		}
+	} else {
+		long src_load, dst_load, load;
+		/*
+		 * If the improvement from just moving env->p direction is better
+		 * than swapping tasks around, check if a move is possible.
+		 */
+		load = task_h_load(env->p);
+		dst_load = env->dst_stats.load + load;
+		src_load = env->src_stats.load - load;
+		maymove = !load_too_imbalanced(src_load, dst_load, env);
+	}
+
+	for_each_cpu(cpu, cpumask_of_node(env->dst_nid)) {
+		/* Skip this CPU if the source task cannot migrate */
+		if (!cpumask_test_cpu(cpu, env->p->cpus_ptr))
+			continue;
+
+		env->dst_cpu = cpu;
+		if (task_numa_compare(env, taskimp, groupimp, maymove))
+			break;
+	}
+}
+
+static int task_numa_migrate(struct task_struct *p)
+{
+	struct task_numa_env env = {
+		.p = p,
+
+		.src_cpu = task_cpu(p),
+		.src_nid = task_node(p),
+
+		.imbalance_pct = 112,
+
+		.best_task = NULL,
+		.best_imp = 0,
+		.best_cpu = -1,
+	};
+	unsigned long taskweight, groupweight;
+	struct sched_domain *sd;
+	long taskimp, groupimp;
+	struct numa_group *ng;
+	struct rq *best_rq;
+	int nid, ret, dist;
+
+	/*
+	 * Pick the lowest SD_NUMA domain, as that would have the smallest
+	 * imbalance and would be the first to start moving tasks about.
+	 *
+	 * And we want to avoid any moving of tasks about, as that would create
+	 * random movement of tasks -- counter the numa conditions we're trying
+	 * to satisfy here.
+	 */
+	rcu_read_lock();
+	sd = rcu_dereference(per_cpu(sd_numa, env.src_cpu));
+	if (sd) {
+		env.imbalance_pct = 100 + (sd->imbalance_pct - 100) / 2;
+		env.imb_numa_nr = sd->imb_numa_nr;
+	}
+	rcu_read_unlock();
+
+	/*
+	 * Cpusets can break the scheduler domain tree into smaller
+	 * balance domains, some of which do not cross NUMA boundaries.
+	 * Tasks that are "trapped" in such domains cannot be migrated
+	 * elsewhere, so there is no point in (re)trying.
+	 */
+	if (unlikely(!sd)) {
+		sched_setnuma(p, task_node(p));
+		return -EINVAL;
+	}
+
+	env.dst_nid = p->numa_preferred_nid;
+	dist = env.dist = node_distance(env.src_nid, env.dst_nid);
+	taskweight = task_weight(p, env.src_nid, dist);
+	groupweight = group_weight(p, env.src_nid, dist);
+	update_numa_stats(&env, &env.src_stats, env.src_nid, false);
+	taskimp = task_weight(p, env.dst_nid, dist) - taskweight;
+	groupimp = group_weight(p, env.dst_nid, dist) - groupweight;
+	update_numa_stats(&env, &env.dst_stats, env.dst_nid, true);
+
+	/* Try to find a spot on the preferred nid. */
+	task_numa_find_cpu(&env, taskimp, groupimp);
+
+	/*
+	 * Look at other nodes in these cases:
+	 * - there is no space available on the preferred_nid
+	 * - the task is part of a numa_group that is interleaved across
+	 *   multiple NUMA nodes; in order to better consolidate the group,
+	 *   we need to check other locations.
+	 */
+	ng = deref_curr_numa_group(p);
+	if (env.best_cpu == -1 || (ng && ng->active_nodes > 1)) {
+		for_each_node_state(nid, N_CPU) {
+			if (nid == env.src_nid || nid == p->numa_preferred_nid)
+				continue;
+
+			dist = node_distance(env.src_nid, env.dst_nid);
+			if (sched_numa_topology_type == NUMA_BACKPLANE &&
+						dist != env.dist) {
+				taskweight = task_weight(p, env.src_nid, dist);
+				groupweight = group_weight(p, env.src_nid, dist);
+			}
+
+			/* Only consider nodes where both task and groups benefit */
+			taskimp = task_weight(p, nid, dist) - taskweight;
+			groupimp = group_weight(p, nid, dist) - groupweight;
+			if (taskimp < 0 && groupimp < 0)
+				continue;
+
+			env.dist = dist;
+			env.dst_nid = nid;
+			update_numa_stats(&env, &env.dst_stats, env.dst_nid, true);
+			task_numa_find_cpu(&env, taskimp, groupimp);
+		}
+	}
+
+	/*
+	 * If the task is part of a workload that spans multiple NUMA nodes,
+	 * and is migrating into one of the workload's active nodes, remember
+	 * this node as the task's preferred numa node, so the workload can
+	 * settle down.
+	 * A task that migrated to a second choice node will be better off
+	 * trying for a better one later. Do not set the preferred node here.
+	 */
+	if (ng) {
+		if (env.best_cpu == -1)
+			nid = env.src_nid;
+		else
+			nid = cpu_to_node(env.best_cpu);
+
+		if (nid != p->numa_preferred_nid)
+			sched_setnuma(p, nid);
+	}
+
+	/* No better CPU than the current one was found. */
+	if (env.best_cpu == -1) {
+		trace_sched_stick_numa(p, env.src_cpu, NULL, -1);
+		return -EAGAIN;
+	}
+
+	best_rq = cpu_rq(env.best_cpu);
+	if (env.best_task == NULL) {
+		ret = migrate_task_to(p, env.best_cpu);
+		WRITE_ONCE(best_rq->numa_migrate_on, 0);
+		if (ret != 0)
+			trace_sched_stick_numa(p, env.src_cpu, NULL, env.best_cpu);
+		return ret;
+	}
+
+	ret = migrate_swap(p, env.best_task, env.best_cpu, env.src_cpu);
+	WRITE_ONCE(best_rq->numa_migrate_on, 0);
+
+	if (ret != 0)
+		trace_sched_stick_numa(p, env.src_cpu, env.best_task, env.best_cpu);
+	put_task_struct(env.best_task);
+	return ret;
+}
+
+/* Attempt to migrate a task to a CPU on the preferred node. */
+static void numa_migrate_preferred(struct task_struct *p)
+{
+	unsigned long interval = HZ;
+
+	/* This task has no NUMA fault statistics yet */
+	if (unlikely(p->numa_preferred_nid == NUMA_NO_NODE || !p->numa_faults))
+		return;
+
+	/* Periodically retry migrating the task to the preferred node */
+	interval = min(interval, msecs_to_jiffies(p->numa_scan_period) / 16);
+	p->numa_migrate_retry = jiffies + interval;
+
+	/* Success if task is already running on preferred CPU */
+	if (task_node(p) == p->numa_preferred_nid)
+		return;
+
+	/* Otherwise, try migrate to a CPU on the preferred node */
+	task_numa_migrate(p);
+}
+
+/*
+ * Find out how many nodes the workload is actively running on. Do this by
+ * tracking the nodes from which NUMA hinting faults are triggered. This can
+ * be different from the set of nodes where the workload's memory is currently
+ * located.
+ */
+static void numa_group_count_active_nodes(struct numa_group *numa_group)
+{
+	unsigned long faults, max_faults = 0;
+	int nid, active_nodes = 0;
+
+	for_each_node_state(nid, N_CPU) {
+		faults = group_faults_cpu(numa_group, nid);
+		if (faults > max_faults)
+			max_faults = faults;
+	}
+
+	for_each_node_state(nid, N_CPU) {
+		faults = group_faults_cpu(numa_group, nid);
+		if (faults * ACTIVE_NODE_FRACTION > max_faults)
+			active_nodes++;
+	}
+
+	numa_group->max_faults_cpu = max_faults;
+	numa_group->active_nodes = active_nodes;
+}
+
+/*
+ * When adapting the scan rate, the period is divided into NUMA_PERIOD_SLOTS
+ * increments. The more local the fault statistics are, the higher the scan
+ * period will be for the next scan window. If local/(local+remote) ratio is
+ * below NUMA_PERIOD_THRESHOLD (where range of ratio is 1..NUMA_PERIOD_SLOTS)
+ * the scan period will decrease. Aim for 70% local accesses.
+ */
+#define NUMA_PERIOD_SLOTS 10
+#define NUMA_PERIOD_THRESHOLD 7
+
+/*
+ * Increase the scan period (slow down scanning) if the majority of
+ * our memory is already on our local node, or if the majority of
+ * the page accesses are shared with other processes.
+ * Otherwise, decrease the scan period.
+ */
+static void update_task_scan_period(struct task_struct *p,
+			unsigned long shared, unsigned long private)
+{
+	unsigned int period_slot;
+	int lr_ratio, ps_ratio;
+	int diff;
+
+	unsigned long remote = p->numa_faults_locality[0];
+	unsigned long local = p->numa_faults_locality[1];
+
+	/*
+	 * If there were no record hinting faults then either the task is
+	 * completely idle or all activity is in areas that are not of interest
+	 * to automatic numa balancing. Related to that, if there were failed
+	 * migration then it implies we are migrating too quickly or the local
+	 * node is overloaded. In either case, scan slower
+	 */
+	if (local + shared == 0 || p->numa_faults_locality[2]) {
+		p->numa_scan_period = min(p->numa_scan_period_max,
+			p->numa_scan_period << 1);
+
+		p->mm->numa_next_scan = jiffies +
+			msecs_to_jiffies(p->numa_scan_period);
+
+		return;
+	}
+
+	/*
+	 * Prepare to scale scan period relative to the current period.
+	 *	 == NUMA_PERIOD_THRESHOLD scan period stays the same
+	 *       <  NUMA_PERIOD_THRESHOLD scan period decreases (scan faster)
+	 *	 >= NUMA_PERIOD_THRESHOLD scan period increases (scan slower)
+	 */
+	period_slot = DIV_ROUND_UP(p->numa_scan_period, NUMA_PERIOD_SLOTS);
+	lr_ratio = (local * NUMA_PERIOD_SLOTS) / (local + remote);
+	ps_ratio = (private * NUMA_PERIOD_SLOTS) / (private + shared);
+
+	if (ps_ratio >= NUMA_PERIOD_THRESHOLD) {
+		/*
+		 * Most memory accesses are local. There is no need to
+		 * do fast NUMA scanning, since memory is already local.
+		 */
+		int slot = ps_ratio - NUMA_PERIOD_THRESHOLD;
+		if (!slot)
+			slot = 1;
+		diff = slot * period_slot;
+	} else if (lr_ratio >= NUMA_PERIOD_THRESHOLD) {
+		/*
+		 * Most memory accesses are shared with other tasks.
+		 * There is no point in continuing fast NUMA scanning,
+		 * since other tasks may just move the memory elsewhere.
+		 */
+		int slot = lr_ratio - NUMA_PERIOD_THRESHOLD;
+		if (!slot)
+			slot = 1;
+		diff = slot * period_slot;
+	} else {
+		/*
+		 * Private memory faults exceed (SLOTS-THRESHOLD)/SLOTS,
+		 * yet they are not on the local NUMA node. Speed up
+		 * NUMA scanning to get the memory moved over.
+		 */
+		int ratio = max(lr_ratio, ps_ratio);
+		diff = -(NUMA_PERIOD_THRESHOLD - ratio) * period_slot;
+	}
+
+	p->numa_scan_period = clamp(p->numa_scan_period + diff,
+			task_scan_min(p), task_scan_max(p));
+	memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality));
+}
+
+/*
+ * Get the fraction of time the task has been running since the last
+ * NUMA placement cycle. The scheduler keeps similar statistics, but
+ * decays those on a 32ms period, which is orders of magnitude off
+ * from the dozens-of-seconds NUMA balancing period. Use the scheduler
+ * stats only if the task is so new there are no NUMA statistics yet.
+ */
+static u64 numa_get_avg_runtime(struct task_struct *p, u64 *period)
+{
+	u64 runtime, delta, now;
+	/* Use the start of this time slice to avoid calculations. */
+	now = p->se.exec_start;
+	runtime = p->se.sum_exec_runtime;
+
+	if (p->last_task_numa_placement) {
+		delta = runtime - p->last_sum_exec_runtime;
+		*period = now - p->last_task_numa_placement;
+
+		/* Avoid time going backwards, prevent potential divide error: */
+		if (unlikely((s64)*period < 0))
+			*period = 0;
+	} else {
+		delta = p->se.avg.load_sum;
+		*period = LOAD_AVG_MAX;
+	}
+
+	p->last_sum_exec_runtime = runtime;
+	p->last_task_numa_placement = now;
+
+	return delta;
+}
+
+/*
+ * Determine the preferred nid for a task in a numa_group. This needs to
+ * be done in a way that produces consistent results with group_weight,
+ * otherwise workloads might not converge.
+ */
+static int preferred_group_nid(struct task_struct *p, int nid)
+{
+	nodemask_t nodes;
+	int dist;
+
+	/* Direct connections between all NUMA nodes. */
+	if (sched_numa_topology_type == NUMA_DIRECT)
+		return nid;
+
+	/*
+	 * On a system with glueless mesh NUMA topology, group_weight
+	 * scores nodes according to the number of NUMA hinting faults on
+	 * both the node itself, and on nearby nodes.
+	 */
+	if (sched_numa_topology_type == NUMA_GLUELESS_MESH) {
+		unsigned long score, max_score = 0;
+		int node, max_node = nid;
+
+		dist = sched_max_numa_distance;
+
+		for_each_node_state(node, N_CPU) {
+			score = group_weight(p, node, dist);
+			if (score > max_score) {
+				max_score = score;
+				max_node = node;
+			}
+		}
+		return max_node;
+	}
+
+	/*
+	 * Finding the preferred nid in a system with NUMA backplane
+	 * interconnect topology is more involved. The goal is to locate
+	 * tasks from numa_groups near each other in the system, and
+	 * untangle workloads from different sides of the system. This requires
+	 * searching down the hierarchy of node groups, recursively searching
+	 * inside the highest scoring group of nodes. The nodemask tricks
+	 * keep the complexity of the search down.
+	 */
+	nodes = node_states[N_CPU];
+	for (dist = sched_max_numa_distance; dist > LOCAL_DISTANCE; dist--) {
+		unsigned long max_faults = 0;
+		nodemask_t max_group = NODE_MASK_NONE;
+		int a, b;
+
+		/* Are there nodes at this distance from each other? */
+		if (!find_numa_distance(dist))
+			continue;
+
+		for_each_node_mask(a, nodes) {
+			unsigned long faults = 0;
+			nodemask_t this_group;
+			nodes_clear(this_group);
+
+			/* Sum group's NUMA faults; includes a==b case. */
+			for_each_node_mask(b, nodes) {
+				if (node_distance(a, b) < dist) {
+					faults += group_faults(p, b);
+					node_set(b, this_group);
+					node_clear(b, nodes);
+				}
+			}
+
+			/* Remember the top group. */
+			if (faults > max_faults) {
+				max_faults = faults;
+				max_group = this_group;
+				/*
+				 * subtle: at the smallest distance there is
+				 * just one node left in each "group", the
+				 * winner is the preferred nid.
+				 */
+				nid = a;
+			}
+		}
+		/* Next round, evaluate the nodes within max_group. */
+		if (!max_faults)
+			break;
+		nodes = max_group;
+	}
+	return nid;
+}
+
+static void task_numa_placement(struct task_struct *p)
+{
+	int seq, nid, max_nid = NUMA_NO_NODE;
+	unsigned long max_faults = 0;
+	unsigned long fault_types[2] = { 0, 0 };
+	unsigned long total_faults;
+	u64 runtime, period;
+	spinlock_t *group_lock = NULL;
+	struct numa_group *ng;
+
+	/*
+	 * The p->mm->numa_scan_seq field gets updated without
+	 * exclusive access. Use READ_ONCE() here to ensure
+	 * that the field is read in a single access:
+	 */
+	seq = READ_ONCE(p->mm->numa_scan_seq);
+	if (p->numa_scan_seq == seq)
+		return;
+	p->numa_scan_seq = seq;
+	p->numa_scan_period_max = task_scan_max(p);
+
+	total_faults = p->numa_faults_locality[0] +
+		       p->numa_faults_locality[1];
+	runtime = numa_get_avg_runtime(p, &period);
+
+	/* If the task is part of a group prevent parallel updates to group stats */
+	ng = deref_curr_numa_group(p);
+	if (ng) {
+		group_lock = &ng->lock;
+		spin_lock_irq(group_lock);
+	}
+
+	/* Find the node with the highest number of faults */
+	for_each_online_node(nid) {
+		/* Keep track of the offsets in numa_faults array */
+		int mem_idx, membuf_idx, cpu_idx, cpubuf_idx;
+		unsigned long faults = 0, group_faults = 0;
+		int priv;
+
+		for (priv = 0; priv < NR_NUMA_HINT_FAULT_TYPES; priv++) {
+			long diff, f_diff, f_weight;
+
+			mem_idx = task_faults_idx(NUMA_MEM, nid, priv);
+			membuf_idx = task_faults_idx(NUMA_MEMBUF, nid, priv);
+			cpu_idx = task_faults_idx(NUMA_CPU, nid, priv);
+			cpubuf_idx = task_faults_idx(NUMA_CPUBUF, nid, priv);
+
+			/* Decay existing window, copy faults since last scan */
+			diff = p->numa_faults[membuf_idx] - p->numa_faults[mem_idx] / 2;
+			fault_types[priv] += p->numa_faults[membuf_idx];
+			p->numa_faults[membuf_idx] = 0;
+
+			/*
+			 * Normalize the faults_from, so all tasks in a group
+			 * count according to CPU use, instead of by the raw
+			 * number of faults. Tasks with little runtime have
+			 * little over-all impact on throughput, and thus their
+			 * faults are less important.
+			 */
+			f_weight = div64_u64(runtime << 16, period + 1);
+			f_weight = (f_weight * p->numa_faults[cpubuf_idx]) /
+				   (total_faults + 1);
+			f_diff = f_weight - p->numa_faults[cpu_idx] / 2;
+			p->numa_faults[cpubuf_idx] = 0;
+
+			p->numa_faults[mem_idx] += diff;
+			p->numa_faults[cpu_idx] += f_diff;
+			faults += p->numa_faults[mem_idx];
+			p->total_numa_faults += diff;
+			if (ng) {
+				/*
+				 * safe because we can only change our own group
+				 *
+				 * mem_idx represents the offset for a given
+				 * nid and priv in a specific region because it
+				 * is at the beginning of the numa_faults array.
+				 */
+				ng->faults[mem_idx] += diff;
+				ng->faults[cpu_idx] += f_diff;
+				ng->total_faults += diff;
+				group_faults += ng->faults[mem_idx];
+			}
+		}
+
+		if (!ng) {
+			if (faults > max_faults) {
+				max_faults = faults;
+				max_nid = nid;
+			}
+		} else if (group_faults > max_faults) {
+			max_faults = group_faults;
+			max_nid = nid;
+		}
+	}
+
+	/* Cannot migrate task to CPU-less node */
+	if (max_nid != NUMA_NO_NODE && !node_state(max_nid, N_CPU)) {
+		int near_nid = max_nid;
+		int distance, near_distance = INT_MAX;
+
+		for_each_node_state(nid, N_CPU) {
+			distance = node_distance(max_nid, nid);
+			if (distance < near_distance) {
+				near_nid = nid;
+				near_distance = distance;
+			}
+		}
+		max_nid = near_nid;
+	}
+
+	if (ng) {
+		numa_group_count_active_nodes(ng);
+		spin_unlock_irq(group_lock);
+		max_nid = preferred_group_nid(p, max_nid);
+	}
+
+	if (max_faults) {
+		/* Set the new preferred node */
+		if (max_nid != p->numa_preferred_nid)
+			sched_setnuma(p, max_nid);
+	}
+
+	update_task_scan_period(p, fault_types[0], fault_types[1]);
+}
+
+static inline int get_numa_group(struct numa_group *grp)
+{
+	return refcount_inc_not_zero(&grp->refcount);
+}
+
+static inline void put_numa_group(struct numa_group *grp)
+{
+	if (refcount_dec_and_test(&grp->refcount))
+		kfree_rcu(grp, rcu);
+}
+
+static void task_numa_group(struct task_struct *p, int cpupid, int flags,
+			int *priv)
+{
+	struct numa_group *grp, *my_grp;
+	struct task_struct *tsk;
+	bool join = false;
+	int cpu = cpupid_to_cpu(cpupid);
+	int i;
+
+	if (unlikely(!deref_curr_numa_group(p))) {
+		unsigned int size = sizeof(struct numa_group) +
+				    NR_NUMA_HINT_FAULT_STATS *
+				    nr_node_ids * sizeof(unsigned long);
+
+		grp = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
+		if (!grp)
+			return;
+
+		refcount_set(&grp->refcount, 1);
+		grp->active_nodes = 1;
+		grp->max_faults_cpu = 0;
+		spin_lock_init(&grp->lock);
+		grp->gid = p->pid;
+
+		for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
+			grp->faults[i] = p->numa_faults[i];
+
+		grp->total_faults = p->total_numa_faults;
+
+		grp->nr_tasks++;
+		rcu_assign_pointer(p->numa_group, grp);
+	}
+
+	rcu_read_lock();
+	tsk = READ_ONCE(cpu_rq(cpu)->curr);
+
+	if (!cpupid_match_pid(tsk, cpupid))
+		goto no_join;
+
+	grp = rcu_dereference(tsk->numa_group);
+	if (!grp)
+		goto no_join;
+
+	my_grp = deref_curr_numa_group(p);
+	if (grp == my_grp)
+		goto no_join;
+
+	/*
+	 * Only join the other group if its bigger; if we're the bigger group,
+	 * the other task will join us.
+	 */
+	if (my_grp->nr_tasks > grp->nr_tasks)
+		goto no_join;
+
+	/*
+	 * Tie-break on the grp address.
+	 */
+	if (my_grp->nr_tasks == grp->nr_tasks && my_grp > grp)
+		goto no_join;
+
+	/* Always join threads in the same process. */
+	if (tsk->mm == current->mm)
+		join = true;
+
+	/* Simple filter to avoid false positives due to PID collisions */
+	if (flags & TNF_SHARED)
+		join = true;
+
+	/* Update priv based on whether false sharing was detected */
+	*priv = !join;
+
+	if (join && !get_numa_group(grp))
+		goto no_join;
+
+	rcu_read_unlock();
+
+	if (!join)
+		return;
+
+	WARN_ON_ONCE(irqs_disabled());
+	double_lock_irq(&my_grp->lock, &grp->lock);
+
+	for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) {
+		my_grp->faults[i] -= p->numa_faults[i];
+		grp->faults[i] += p->numa_faults[i];
+	}
+	my_grp->total_faults -= p->total_numa_faults;
+	grp->total_faults += p->total_numa_faults;
+
+	my_grp->nr_tasks--;
+	grp->nr_tasks++;
+
+	spin_unlock(&my_grp->lock);
+	spin_unlock_irq(&grp->lock);
+
+	rcu_assign_pointer(p->numa_group, grp);
+
+	put_numa_group(my_grp);
+	return;
+
+no_join:
+	rcu_read_unlock();
+	return;
+}
+
+/*
+ * Get rid of NUMA statistics associated with a task (either current or dead).
+ * If @final is set, the task is dead and has reached refcount zero, so we can
+ * safely free all relevant data structures. Otherwise, there might be
+ * concurrent reads from places like load balancing and procfs, and we should
+ * reset the data back to default state without freeing ->numa_faults.
+ */
+void task_numa_free(struct task_struct *p, bool final)
+{
+	/* safe: p either is current or is being freed by current */
+	struct numa_group *grp = rcu_dereference_raw(p->numa_group);
+	unsigned long *numa_faults = p->numa_faults;
+	unsigned long flags;
+	int i;
+
+	if (!numa_faults)
+		return;
+
+	if (grp) {
+		spin_lock_irqsave(&grp->lock, flags);
+		for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
+			grp->faults[i] -= p->numa_faults[i];
+		grp->total_faults -= p->total_numa_faults;
+
+		grp->nr_tasks--;
+		spin_unlock_irqrestore(&grp->lock, flags);
+		RCU_INIT_POINTER(p->numa_group, NULL);
+		put_numa_group(grp);
+	}
+
+	if (final) {
+		p->numa_faults = NULL;
+		kfree(numa_faults);
+	} else {
+		p->total_numa_faults = 0;
+		for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
+			numa_faults[i] = 0;
+	}
+}
+
+/*
+ * Got a PROT_NONE fault for a page on @node.
+ */
+void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
+{
+	struct task_struct *p = current;
+	bool migrated = flags & TNF_MIGRATED;
+	int cpu_node = task_node(current);
+	int local = !!(flags & TNF_FAULT_LOCAL);
+	struct numa_group *ng;
+	int priv;
+
+	if (!static_branch_likely(&sched_numa_balancing))
+		return;
+
+	/* for example, ksmd faulting in a user's mm */
+	if (!p->mm)
+		return;
+
+	/*
+	 * NUMA faults statistics are unnecessary for the slow memory
+	 * node for memory tiering mode.
+	 */
+	if (!node_is_toptier(mem_node) &&
+	    (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING ||
+	     !cpupid_valid(last_cpupid)))
+		return;
+
+	/* Allocate buffer to track faults on a per-node basis */
+	if (unlikely(!p->numa_faults)) {
+		int size = sizeof(*p->numa_faults) *
+			   NR_NUMA_HINT_FAULT_BUCKETS * nr_node_ids;
+
+		p->numa_faults = kzalloc(size, GFP_KERNEL|__GFP_NOWARN);
+		if (!p->numa_faults)
+			return;
+
+		p->total_numa_faults = 0;
+		memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality));
+	}
+
+	/*
+	 * First accesses are treated as private, otherwise consider accesses
+	 * to be private if the accessing pid has not changed
+	 */
+	if (unlikely(last_cpupid == (-1 & LAST_CPUPID_MASK))) {
+		priv = 1;
+	} else {
+		priv = cpupid_match_pid(p, last_cpupid);
+		if (!priv && !(flags & TNF_NO_GROUP))
+			task_numa_group(p, last_cpupid, flags, &priv);
+	}
+
+	/*
+	 * If a workload spans multiple NUMA nodes, a shared fault that
+	 * occurs wholly within the set of nodes that the workload is
+	 * actively using should be counted as local. This allows the
+	 * scan rate to slow down when a workload has settled down.
+	 */
+	ng = deref_curr_numa_group(p);
+	if (!priv && !local && ng && ng->active_nodes > 1 &&
+				numa_is_active_node(cpu_node, ng) &&
+				numa_is_active_node(mem_node, ng))
+		local = 1;
+
+	/*
+	 * Retry to migrate task to preferred node periodically, in case it
+	 * previously failed, or the scheduler moved us.
+	 */
+	if (time_after(jiffies, p->numa_migrate_retry)) {
+		task_numa_placement(p);
+		numa_migrate_preferred(p);
+	}
+
+	if (migrated)
+		p->numa_pages_migrated += pages;
+	if (flags & TNF_MIGRATE_FAIL)
+		p->numa_faults_locality[2] += pages;
+
+	p->numa_faults[task_faults_idx(NUMA_MEMBUF, mem_node, priv)] += pages;
+	p->numa_faults[task_faults_idx(NUMA_CPUBUF, cpu_node, priv)] += pages;
+	p->numa_faults_locality[local] += pages;
+}
+
+static void reset_ptenuma_scan(struct task_struct *p)
+{
+	/*
+	 * We only did a read acquisition of the mmap sem, so
+	 * p->mm->numa_scan_seq is written to without exclusive access
+	 * and the update is not guaranteed to be atomic. That's not
+	 * much of an issue though, since this is just used for
+	 * statistical sampling. Use READ_ONCE/WRITE_ONCE, which are not
+	 * expensive, to avoid any form of compiler optimizations:
+	 */
+	WRITE_ONCE(p->mm->numa_scan_seq, READ_ONCE(p->mm->numa_scan_seq) + 1);
+	p->mm->numa_scan_offset = 0;
+}
+
+/*
+ * The expensive part of numa migration is done from task_work context.
+ * Triggered from task_tick_numa().
+ */
+static void task_numa_work(struct callback_head *work)
+{
+	unsigned long migrate, next_scan, now = jiffies;
+	struct task_struct *p = current;
+	struct mm_struct *mm = p->mm;
+	u64 runtime = p->se.sum_exec_runtime;
+	MA_STATE(mas, &mm->mm_mt, 0, 0);
+	struct vm_area_struct *vma;
+	unsigned long start, end;
+	unsigned long nr_pte_updates = 0;
+	long pages, virtpages;
+
+	SCHED_WARN_ON(p != container_of(work, struct task_struct, numa_work));
+
+	work->next = work;
+	/*
+	 * Who cares about NUMA placement when they're dying.
+	 *
+	 * NOTE: make sure not to dereference p->mm before this check,
+	 * exit_task_work() happens _after_ exit_mm() so we could be called
+	 * without p->mm even though we still had it when we enqueued this
+	 * work.
+	 */
+	if (p->flags & PF_EXITING)
+		return;
+
+	if (!mm->numa_next_scan) {
+		mm->numa_next_scan = now +
+			msecs_to_jiffies(sysctl_numa_balancing_scan_delay);
+	}
+
+	/*
+	 * Enforce maximal scan/migration frequency..
+	 */
+	migrate = mm->numa_next_scan;
+	if (time_before(now, migrate))
+		return;
+
+	if (p->numa_scan_period == 0) {
+		p->numa_scan_period_max = task_scan_max(p);
+		p->numa_scan_period = task_scan_start(p);
+	}
+
+	next_scan = now + msecs_to_jiffies(p->numa_scan_period);
+	if (cmpxchg(&mm->numa_next_scan, migrate, next_scan) != migrate)
+		return;
+
+	/*
+	 * Delay this task enough that another task of this mm will likely win
+	 * the next time around.
+	 */
+	p->node_stamp += 2 * TICK_NSEC;
+
+	start = mm->numa_scan_offset;
+	pages = sysctl_numa_balancing_scan_size;
+	pages <<= 20 - PAGE_SHIFT; /* MB in pages */
+	virtpages = pages * 8;	   /* Scan up to this much virtual space */
+	if (!pages)
+		return;
+
+
+	if (!mmap_read_trylock(mm))
+		return;
+	mas_set(&mas, start);
+	vma = mas_find(&mas, ULONG_MAX);
+	if (!vma) {
+		reset_ptenuma_scan(p);
+		start = 0;
+		mas_set(&mas, start);
+		vma = mas_find(&mas, ULONG_MAX);
+	}
+
+	for (; vma; vma = mas_find(&mas, ULONG_MAX)) {
+		if (!vma_migratable(vma) || !vma_policy_mof(vma) ||
+			is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_MIXEDMAP)) {
+			continue;
+		}
+
+		/*
+		 * Shared library pages mapped by multiple processes are not
+		 * migrated as it is expected they are cache replicated. Avoid
+		 * hinting faults in read-only file-backed mappings or the vdso
+		 * as migrating the pages will be of marginal benefit.
+		 */
+		if (!vma->vm_mm ||
+		    (vma->vm_file && (vma->vm_flags & (VM_READ|VM_WRITE)) == (VM_READ)))
+			continue;
+
+		/*
+		 * Skip inaccessible VMAs to avoid any confusion between
+		 * PROT_NONE and NUMA hinting ptes
+		 */
+		if (!vma_is_accessible(vma))
+			continue;
+
+		do {
+			start = max(start, vma->vm_start);
+			end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE);
+			end = min(end, vma->vm_end);
+			nr_pte_updates = change_prot_numa(vma, start, end);
+
+			/*
+			 * Try to scan sysctl_numa_balancing_size worth of
+			 * hpages that have at least one present PTE that
+			 * is not already pte-numa. If the VMA contains
+			 * areas that are unused or already full of prot_numa
+			 * PTEs, scan up to virtpages, to skip through those
+			 * areas faster.
+			 */
+			if (nr_pte_updates)
+				pages -= (end - start) >> PAGE_SHIFT;
+			virtpages -= (end - start) >> PAGE_SHIFT;
+
+			start = end;
+			if (pages <= 0 || virtpages <= 0)
+				goto out;
+
+			cond_resched();
+		} while (end != vma->vm_end);
+	}
+
+out:
+	/*
+	 * It is possible to reach the end of the VMA list but the last few
+	 * VMAs are not guaranteed to the vma_migratable. If they are not, we
+	 * would find the !migratable VMA on the next scan but not reset the
+	 * scanner to the start so check it now.
+	 */
+	if (vma)
+		mm->numa_scan_offset = start;
+	else
+		reset_ptenuma_scan(p);
+	mmap_read_unlock(mm);
+
+	/*
+	 * Make sure tasks use at least 32x as much time to run other code
+	 * than they used here, to limit NUMA PTE scanning overhead to 3% max.
+	 * Usually update_task_scan_period slows down scanning enough; on an
+	 * overloaded system we need to limit overhead on a per task basis.
+	 */
+	if (unlikely(p->se.sum_exec_runtime != runtime)) {
+		u64 diff = p->se.sum_exec_runtime - runtime;
+		p->node_stamp += 32 * diff;
+	}
+}
+
+void init_numa_balancing(unsigned long clone_flags, struct task_struct *p)
+{
+	int mm_users = 0;
+	struct mm_struct *mm = p->mm;
+
+	if (mm) {
+		mm_users = atomic_read(&mm->mm_users);
+		if (mm_users == 1) {
+			mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay);
+			mm->numa_scan_seq = 0;
+		}
+	}
+	p->node_stamp			= 0;
+	p->numa_scan_seq		= mm ? mm->numa_scan_seq : 0;
+	p->numa_scan_period		= sysctl_numa_balancing_scan_delay;
+	p->numa_migrate_retry		= 0;
+	/* Protect against double add, see task_tick_numa and task_numa_work */
+	p->numa_work.next		= &p->numa_work;
+	p->numa_faults			= NULL;
+	p->numa_pages_migrated		= 0;
+	p->total_numa_faults		= 0;
+	RCU_INIT_POINTER(p->numa_group, NULL);
+	p->last_task_numa_placement	= 0;
+	p->last_sum_exec_runtime	= 0;
+
+	init_task_work(&p->numa_work, task_numa_work);
+
+	/* New address space, reset the preferred nid */
+	if (!(clone_flags & CLONE_VM)) {
+		p->numa_preferred_nid = NUMA_NO_NODE;
+		return;
+	}
+
+	/*
+	 * New thread, keep existing numa_preferred_nid which should be copied
+	 * already by arch_dup_task_struct but stagger when scans start.
+	 */
+	if (mm) {
+		unsigned int delay;
+
+		delay = min_t(unsigned int, task_scan_max(current),
+			current->numa_scan_period * mm_users * NSEC_PER_MSEC);
+		delay += 2 * TICK_NSEC;
+		p->node_stamp = delay;
+	}
+}
+
+/*
+ * Drive the periodic memory faults..
+ */
+static void task_tick_numa(struct rq *rq, struct task_struct *curr)
+{
+	struct callback_head *work = &curr->numa_work;
+	u64 period, now;
+
+	/*
+	 * We don't care about NUMA placement if we don't have memory.
+	 */
+	if (!curr->mm || (curr->flags & (PF_EXITING | PF_KTHREAD)) || work->next != work)
+		return;
+
+	/*
+	 * Using runtime rather than walltime has the dual advantage that
+	 * we (mostly) drive the selection from busy threads and that the
+	 * task needs to have done some actual work before we bother with
+	 * NUMA placement.
+	 */
+	now = curr->se.sum_exec_runtime;
+	period = (u64)curr->numa_scan_period * NSEC_PER_MSEC;
+
+	if (now > curr->node_stamp + period) {
+		if (!curr->node_stamp)
+			curr->numa_scan_period = task_scan_start(curr);
+		curr->node_stamp += period;
+
+		if (!time_before(jiffies, curr->mm->numa_next_scan))
+			task_work_add(curr, work, TWA_RESUME);
+	}
+}
+
+static void update_scan_period(struct task_struct *p, int new_cpu)
+{
+	int src_nid = cpu_to_node(task_cpu(p));
+	int dst_nid = cpu_to_node(new_cpu);
+
+	if (!static_branch_likely(&sched_numa_balancing))
+		return;
+
+	if (!p->mm || !p->numa_faults || (p->flags & PF_EXITING))
+		return;
+
+	if (src_nid == dst_nid)
+		return;
+
+	/*
+	 * Allow resets if faults have been trapped before one scan
+	 * has completed. This is most likely due to a new task that
+	 * is pulled cross-node due to wakeups or load balancing.
+	 */
+	if (p->numa_scan_seq) {
+		/*
+		 * Avoid scan adjustments if moving to the preferred
+		 * node or if the task was not previously running on
+		 * the preferred node.
+		 */
+		if (dst_nid == p->numa_preferred_nid ||
+		    (p->numa_preferred_nid != NUMA_NO_NODE &&
+			src_nid != p->numa_preferred_nid))
+			return;
+	}
+
+	p->numa_scan_period = task_scan_start(p);
+}
+
+#else
+static void task_tick_numa(struct rq *rq, struct task_struct *curr)
+{
+}
+
+static inline void account_numa_enqueue(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline void account_numa_dequeue(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline void update_scan_period(struct task_struct *p, int new_cpu)
+{
+}
+
+#endif /* CONFIG_NUMA_BALANCING */
+
+static void
+account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	update_load_add(&cfs_rq->load, se->load.weight);
+#ifdef CONFIG_SMP
+	if (entity_is_task(se)) {
+		struct rq *rq = rq_of(cfs_rq);
+
+		account_numa_enqueue(rq, task_of(se));
+		list_add(&se->group_node, &rq->cfs_tasks);
+	}
+#endif
+	cfs_rq->nr_running++;
+	if (se_is_idle(se))
+		cfs_rq->idle_nr_running++;
+}
+
+static void
+account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	update_load_sub(&cfs_rq->load, se->load.weight);
+#ifdef CONFIG_SMP
+	if (entity_is_task(se)) {
+		account_numa_dequeue(rq_of(cfs_rq), task_of(se));
+		list_del_init(&se->group_node);
+	}
+#endif
+	cfs_rq->nr_running--;
+	if (se_is_idle(se))
+		cfs_rq->idle_nr_running--;
+}
+
+/*
+ * Signed add and clamp on underflow.
+ *
+ * Explicitly do a load-store to ensure the intermediate value never hits
+ * memory. This allows lockless observations without ever seeing the negative
+ * values.
+ */
+#define add_positive(_ptr, _val) do {                           \
+	typeof(_ptr) ptr = (_ptr);                              \
+	typeof(_val) val = (_val);                              \
+	typeof(*ptr) res, var = READ_ONCE(*ptr);                \
+								\
+	res = var + val;                                        \
+								\
+	if (val < 0 && res > var)                               \
+		res = 0;                                        \
+								\
+	WRITE_ONCE(*ptr, res);                                  \
+} while (0)
+
+/*
+ * Unsigned subtract and clamp on underflow.
+ *
+ * Explicitly do a load-store to ensure the intermediate value never hits
+ * memory. This allows lockless observations without ever seeing the negative
+ * values.
+ */
+#define sub_positive(_ptr, _val) do {				\
+	typeof(_ptr) ptr = (_ptr);				\
+	typeof(*ptr) val = (_val);				\
+	typeof(*ptr) res, var = READ_ONCE(*ptr);		\
+	res = var - val;					\
+	if (res > var)						\
+		res = 0;					\
+	WRITE_ONCE(*ptr, res);					\
+} while (0)
+
+/*
+ * Remove and clamp on negative, from a local variable.
+ *
+ * A variant of sub_positive(), which does not use explicit load-store
+ * and is thus optimized for local variable updates.
+ */
+#define lsub_positive(_ptr, _val) do {				\
+	typeof(_ptr) ptr = (_ptr);				\
+	*ptr -= min_t(typeof(*ptr), *ptr, _val);		\
+} while (0)
+
+#ifdef CONFIG_SMP
+static inline void
+enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	cfs_rq->avg.load_avg += se->avg.load_avg;
+	cfs_rq->avg.load_sum += se_weight(se) * se->avg.load_sum;
+}
+
+static inline void
+dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	sub_positive(&cfs_rq->avg.load_avg, se->avg.load_avg);
+	sub_positive(&cfs_rq->avg.load_sum, se_weight(se) * se->avg.load_sum);
+	/* See update_cfs_rq_load_avg() */
+	cfs_rq->avg.load_sum = max_t(u32, cfs_rq->avg.load_sum,
+					  cfs_rq->avg.load_avg * PELT_MIN_DIVIDER);
+}
+#else
+static inline void
+enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { }
+static inline void
+dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { }
+#endif
+
+static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
+			    unsigned long weight)
+{
+	if (se->on_rq) {
+		/* commit outstanding execution time */
+		if (cfs_rq->curr == se)
+			update_curr(cfs_rq);
+		update_load_sub(&cfs_rq->load, se->load.weight);
+	}
+	dequeue_load_avg(cfs_rq, se);
+
+	update_load_set(&se->load, weight);
+
+#ifdef CONFIG_SMP
+	do {
+		u32 divider = get_pelt_divider(&se->avg);
+
+		se->avg.load_avg = div_u64(se_weight(se) * se->avg.load_sum, divider);
+	} while (0);
+#endif
+
+	enqueue_load_avg(cfs_rq, se);
+	if (se->on_rq)
+		update_load_add(&cfs_rq->load, se->load.weight);
+
+}
+
+void reweight_task(struct task_struct *p, int prio)
+{
+	struct sched_entity *se = &p->se;
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+	struct load_weight *load = &se->load;
+	unsigned long weight = scale_load(sched_prio_to_weight[prio]);
+
+	reweight_entity(cfs_rq, se, weight);
+	load->inv_weight = sched_prio_to_wmult[prio];
+}
+
+static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_SMP
+/*
+ * All this does is approximate the hierarchical proportion which includes that
+ * global sum we all love to hate.
+ *
+ * That is, the weight of a group entity, is the proportional share of the
+ * group weight based on the group runqueue weights. That is:
+ *
+ *                     tg->weight * grq->load.weight
+ *   ge->load.weight = -----------------------------               (1)
+ *                       \Sum grq->load.weight
+ *
+ * Now, because computing that sum is prohibitively expensive to compute (been
+ * there, done that) we approximate it with this average stuff. The average
+ * moves slower and therefore the approximation is cheaper and more stable.
+ *
+ * So instead of the above, we substitute:
+ *
+ *   grq->load.weight -> grq->avg.load_avg                         (2)
+ *
+ * which yields the following:
+ *
+ *                     tg->weight * grq->avg.load_avg
+ *   ge->load.weight = ------------------------------              (3)
+ *                             tg->load_avg
+ *
+ * Where: tg->load_avg ~= \Sum grq->avg.load_avg
+ *
+ * That is shares_avg, and it is right (given the approximation (2)).
+ *
+ * The problem with it is that because the average is slow -- it was designed
+ * to be exactly that of course -- this leads to transients in boundary
+ * conditions. In specific, the case where the group was idle and we start the
+ * one task. It takes time for our CPU's grq->avg.load_avg to build up,
+ * yielding bad latency etc..
+ *
+ * Now, in that special case (1) reduces to:
+ *
+ *                     tg->weight * grq->load.weight
+ *   ge->load.weight = ----------------------------- = tg->weight   (4)
+ *                         grp->load.weight
+ *
+ * That is, the sum collapses because all other CPUs are idle; the UP scenario.
+ *
+ * So what we do is modify our approximation (3) to approach (4) in the (near)
+ * UP case, like:
+ *
+ *   ge->load.weight =
+ *
+ *              tg->weight * grq->load.weight
+ *     ---------------------------------------------------         (5)
+ *     tg->load_avg - grq->avg.load_avg + grq->load.weight
+ *
+ * But because grq->load.weight can drop to 0, resulting in a divide by zero,
+ * we need to use grq->avg.load_avg as its lower bound, which then gives:
+ *
+ *
+ *                     tg->weight * grq->load.weight
+ *   ge->load.weight = -----------------------------		   (6)
+ *                             tg_load_avg'
+ *
+ * Where:
+ *
+ *   tg_load_avg' = tg->load_avg - grq->avg.load_avg +
+ *                  max(grq->load.weight, grq->avg.load_avg)
+ *
+ * And that is shares_weight and is icky. In the (near) UP case it approaches
+ * (4) while in the normal case it approaches (3). It consistently
+ * overestimates the ge->load.weight and therefore:
+ *
+ *   \Sum ge->load.weight >= tg->weight
+ *
+ * hence icky!
+ */
+static long calc_group_shares(struct cfs_rq *cfs_rq)
+{
+	long tg_weight, tg_shares, load, shares;
+	struct task_group *tg = cfs_rq->tg;
+
+	tg_shares = READ_ONCE(tg->shares);
+
+	load = max(scale_load_down(cfs_rq->load.weight), cfs_rq->avg.load_avg);
+
+	tg_weight = atomic_long_read(&tg->load_avg);
+
+	/* Ensure tg_weight >= load */
+	tg_weight -= cfs_rq->tg_load_avg_contrib;
+	tg_weight += load;
+
+	shares = (tg_shares * load);
+	if (tg_weight)
+		shares /= tg_weight;
+
+	/*
+	 * MIN_SHARES has to be unscaled here to support per-CPU partitioning
+	 * of a group with small tg->shares value. It is a floor value which is
+	 * assigned as a minimum load.weight to the sched_entity representing
+	 * the group on a CPU.
+	 *
+	 * E.g. on 64-bit for a group with tg->shares of scale_load(15)=15*1024
+	 * on an 8-core system with 8 tasks each runnable on one CPU shares has
+	 * to be 15*1024*1/8=1920 instead of scale_load(MIN_SHARES)=2*1024. In
+	 * case no task is runnable on a CPU MIN_SHARES=2 should be returned
+	 * instead of 0.
+	 */
+	return clamp_t(long, shares, MIN_SHARES, tg_shares);
+}
+#endif /* CONFIG_SMP */
+
+/*
+ * Recomputes the group entity based on the current state of its group
+ * runqueue.
+ */
+static void update_cfs_group(struct sched_entity *se)
+{
+	struct cfs_rq *gcfs_rq = group_cfs_rq(se);
+	long shares;
+
+	if (!gcfs_rq)
+		return;
+
+	if (throttled_hierarchy(gcfs_rq))
+		return;
+
+#ifndef CONFIG_SMP
+	shares = READ_ONCE(gcfs_rq->tg->shares);
+
+	if (likely(se->load.weight == shares))
+		return;
+#else
+	shares   = calc_group_shares(gcfs_rq);
+#endif
+
+	reweight_entity(cfs_rq_of(se), se, shares);
+}
+
+#else /* CONFIG_FAIR_GROUP_SCHED */
+static inline void update_cfs_group(struct sched_entity *se)
+{
+}
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq, int flags)
+{
+	struct rq *rq = rq_of(cfs_rq);
+
+	if (&rq->cfs == cfs_rq) {
+		/*
+		 * There are a few boundary cases this might miss but it should
+		 * get called often enough that that should (hopefully) not be
+		 * a real problem.
+		 *
+		 * It will not get called when we go idle, because the idle
+		 * thread is a different class (!fair), nor will the utilization
+		 * number include things like RT tasks.
+		 *
+		 * As is, the util number is not freq-invariant (we'd have to
+		 * implement arch_scale_freq_capacity() for that).
+		 *
+		 * See cpu_util_cfs().
+		 */
+		cpufreq_update_util(rq, flags);
+	}
+}
+
+#ifdef CONFIG_SMP
+static inline bool load_avg_is_decayed(struct sched_avg *sa)
+{
+	if (sa->load_sum)
+		return false;
+
+	if (sa->util_sum)
+		return false;
+
+	if (sa->runnable_sum)
+		return false;
+
+	/*
+	 * _avg must be null when _sum are null because _avg = _sum / divider
+	 * Make sure that rounding and/or propagation of PELT values never
+	 * break this.
+	 */
+	SCHED_WARN_ON(sa->load_avg ||
+		      sa->util_avg ||
+		      sa->runnable_avg);
+
+	return true;
+}
+
+static inline u64 cfs_rq_last_update_time(struct cfs_rq *cfs_rq)
+{
+	return u64_u32_load_copy(cfs_rq->avg.last_update_time,
+				 cfs_rq->last_update_time_copy);
+}
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/*
+ * Because list_add_leaf_cfs_rq always places a child cfs_rq on the list
+ * immediately before a parent cfs_rq, and cfs_rqs are removed from the list
+ * bottom-up, we only have to test whether the cfs_rq before us on the list
+ * is our child.
+ * If cfs_rq is not on the list, test whether a child needs its to be added to
+ * connect a branch to the tree  * (see list_add_leaf_cfs_rq() for details).
+ */
+static inline bool child_cfs_rq_on_list(struct cfs_rq *cfs_rq)
+{
+	struct cfs_rq *prev_cfs_rq;
+	struct list_head *prev;
+
+	if (cfs_rq->on_list) {
+		prev = cfs_rq->leaf_cfs_rq_list.prev;
+	} else {
+		struct rq *rq = rq_of(cfs_rq);
+
+		prev = rq->tmp_alone_branch;
+	}
+
+	prev_cfs_rq = container_of(prev, struct cfs_rq, leaf_cfs_rq_list);
+
+	return (prev_cfs_rq->tg->parent == cfs_rq->tg);
+}
+
+static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
+{
+	if (cfs_rq->load.weight)
+		return false;
+
+	if (!load_avg_is_decayed(&cfs_rq->avg))
+		return false;
+
+	if (child_cfs_rq_on_list(cfs_rq))
+		return false;
+
+	return true;
+}
+
+/**
+ * update_tg_load_avg - update the tg's load avg
+ * @cfs_rq: the cfs_rq whose avg changed
+ *
+ * This function 'ensures': tg->load_avg := \Sum tg->cfs_rq[]->avg.load.
+ * However, because tg->load_avg is a global value there are performance
+ * considerations.
+ *
+ * In order to avoid having to look at the other cfs_rq's, we use a
+ * differential update where we store the last value we propagated. This in
+ * turn allows skipping updates if the differential is 'small'.
+ *
+ * Updating tg's load_avg is necessary before update_cfs_share().
+ */
+static inline void update_tg_load_avg(struct cfs_rq *cfs_rq)
+{
+	long delta = cfs_rq->avg.load_avg - cfs_rq->tg_load_avg_contrib;
+
+	/*
+	 * No need to update load_avg for root_task_group as it is not used.
+	 */
+	if (cfs_rq->tg == &root_task_group)
+		return;
+
+	if (abs(delta) > cfs_rq->tg_load_avg_contrib / 64) {
+		atomic_long_add(delta, &cfs_rq->tg->load_avg);
+		cfs_rq->tg_load_avg_contrib = cfs_rq->avg.load_avg;
+	}
+}
+
+/*
+ * Called within set_task_rq() right before setting a task's CPU. The
+ * caller only guarantees p->pi_lock is held; no other assumptions,
+ * including the state of rq->lock, should be made.
+ */
+void set_task_rq_fair(struct sched_entity *se,
+		      struct cfs_rq *prev, struct cfs_rq *next)
+{
+	u64 p_last_update_time;
+	u64 n_last_update_time;
+
+	if (!sched_feat(ATTACH_AGE_LOAD))
+		return;
+
+	/*
+	 * We are supposed to update the task to "current" time, then its up to
+	 * date and ready to go to new CPU/cfs_rq. But we have difficulty in
+	 * getting what current time is, so simply throw away the out-of-date
+	 * time. This will result in the wakee task is less decayed, but giving
+	 * the wakee more load sounds not bad.
+	 */
+	if (!(se->avg.last_update_time && prev))
+		return;
+
+	p_last_update_time = cfs_rq_last_update_time(prev);
+	n_last_update_time = cfs_rq_last_update_time(next);
+
+	__update_load_avg_blocked_se(p_last_update_time, se);
+	se->avg.last_update_time = n_last_update_time;
+}
+
+/*
+ * When on migration a sched_entity joins/leaves the PELT hierarchy, we need to
+ * propagate its contribution. The key to this propagation is the invariant
+ * that for each group:
+ *
+ *   ge->avg == grq->avg						(1)
+ *
+ * _IFF_ we look at the pure running and runnable sums. Because they
+ * represent the very same entity, just at different points in the hierarchy.
+ *
+ * Per the above update_tg_cfs_util() and update_tg_cfs_runnable() are trivial
+ * and simply copies the running/runnable sum over (but still wrong, because
+ * the group entity and group rq do not have their PELT windows aligned).
+ *
+ * However, update_tg_cfs_load() is more complex. So we have:
+ *
+ *   ge->avg.load_avg = ge->load.weight * ge->avg.runnable_avg		(2)
+ *
+ * And since, like util, the runnable part should be directly transferable,
+ * the following would _appear_ to be the straight forward approach:
+ *
+ *   grq->avg.load_avg = grq->load.weight * grq->avg.runnable_avg	(3)
+ *
+ * And per (1) we have:
+ *
+ *   ge->avg.runnable_avg == grq->avg.runnable_avg
+ *
+ * Which gives:
+ *
+ *                      ge->load.weight * grq->avg.load_avg
+ *   ge->avg.load_avg = -----------------------------------		(4)
+ *                               grq->load.weight
+ *
+ * Except that is wrong!
+ *
+ * Because while for entities historical weight is not important and we
+ * really only care about our future and therefore can consider a pure
+ * runnable sum, runqueues can NOT do this.
+ *
+ * We specifically want runqueues to have a load_avg that includes
+ * historical weights. Those represent the blocked load, the load we expect
+ * to (shortly) return to us. This only works by keeping the weights as
+ * integral part of the sum. We therefore cannot decompose as per (3).
+ *
+ * Another reason this doesn't work is that runnable isn't a 0-sum entity.
+ * Imagine a rq with 2 tasks that each are runnable 2/3 of the time. Then the
+ * rq itself is runnable anywhere between 2/3 and 1 depending on how the
+ * runnable section of these tasks overlap (or not). If they were to perfectly
+ * align the rq as a whole would be runnable 2/3 of the time. If however we
+ * always have at least 1 runnable task, the rq as a whole is always runnable.
+ *
+ * So we'll have to approximate.. :/
+ *
+ * Given the constraint:
+ *
+ *   ge->avg.running_sum <= ge->avg.runnable_sum <= LOAD_AVG_MAX
+ *
+ * We can construct a rule that adds runnable to a rq by assuming minimal
+ * overlap.
+ *
+ * On removal, we'll assume each task is equally runnable; which yields:
+ *
+ *   grq->avg.runnable_sum = grq->avg.load_sum / grq->load.weight
+ *
+ * XXX: only do this for the part of runnable > running ?
+ *
+ */
+static inline void
+update_tg_cfs_util(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
+{
+	long delta_sum, delta_avg = gcfs_rq->avg.util_avg - se->avg.util_avg;
+	u32 new_sum, divider;
+
+	/* Nothing to update */
+	if (!delta_avg)
+		return;
+
+	/*
+	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
+	 * See ___update_load_avg() for details.
+	 */
+	divider = get_pelt_divider(&cfs_rq->avg);
+
+
+	/* Set new sched_entity's utilization */
+	se->avg.util_avg = gcfs_rq->avg.util_avg;
+	new_sum = se->avg.util_avg * divider;
+	delta_sum = (long)new_sum - (long)se->avg.util_sum;
+	se->avg.util_sum = new_sum;
+
+	/* Update parent cfs_rq utilization */
+	add_positive(&cfs_rq->avg.util_avg, delta_avg);
+	add_positive(&cfs_rq->avg.util_sum, delta_sum);
+
+	/* See update_cfs_rq_load_avg() */
+	cfs_rq->avg.util_sum = max_t(u32, cfs_rq->avg.util_sum,
+					  cfs_rq->avg.util_avg * PELT_MIN_DIVIDER);
+}
+
+static inline void
+update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
+{
+	long delta_sum, delta_avg = gcfs_rq->avg.runnable_avg - se->avg.runnable_avg;
+	u32 new_sum, divider;
+
+	/* Nothing to update */
+	if (!delta_avg)
+		return;
+
+	/*
+	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
+	 * See ___update_load_avg() for details.
+	 */
+	divider = get_pelt_divider(&cfs_rq->avg);
+
+	/* Set new sched_entity's runnable */
+	se->avg.runnable_avg = gcfs_rq->avg.runnable_avg;
+	new_sum = se->avg.runnable_avg * divider;
+	delta_sum = (long)new_sum - (long)se->avg.runnable_sum;
+	se->avg.runnable_sum = new_sum;
+
+	/* Update parent cfs_rq runnable */
+	add_positive(&cfs_rq->avg.runnable_avg, delta_avg);
+	add_positive(&cfs_rq->avg.runnable_sum, delta_sum);
+	/* See update_cfs_rq_load_avg() */
+	cfs_rq->avg.runnable_sum = max_t(u32, cfs_rq->avg.runnable_sum,
+					      cfs_rq->avg.runnable_avg * PELT_MIN_DIVIDER);
+}
+
+static inline void
+update_tg_cfs_load(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
+{
+	long delta_avg, running_sum, runnable_sum = gcfs_rq->prop_runnable_sum;
+	unsigned long load_avg;
+	u64 load_sum = 0;
+	s64 delta_sum;
+	u32 divider;
+
+	if (!runnable_sum)
+		return;
+
+	gcfs_rq->prop_runnable_sum = 0;
+
+	/*
+	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
+	 * See ___update_load_avg() for details.
+	 */
+	divider = get_pelt_divider(&cfs_rq->avg);
+
+	if (runnable_sum >= 0) {
+		/*
+		 * Add runnable; clip at LOAD_AVG_MAX. Reflects that until
+		 * the CPU is saturated running == runnable.
+		 */
+		runnable_sum += se->avg.load_sum;
+		runnable_sum = min_t(long, runnable_sum, divider);
+	} else {
+		/*
+		 * Estimate the new unweighted runnable_sum of the gcfs_rq by
+		 * assuming all tasks are equally runnable.
+		 */
+		if (scale_load_down(gcfs_rq->load.weight)) {
+			load_sum = div_u64(gcfs_rq->avg.load_sum,
+				scale_load_down(gcfs_rq->load.weight));
+		}
+
+		/* But make sure to not inflate se's runnable */
+		runnable_sum = min(se->avg.load_sum, load_sum);
+	}
+
+	/*
+	 * runnable_sum can't be lower than running_sum
+	 * Rescale running sum to be in the same range as runnable sum
+	 * running_sum is in [0 : LOAD_AVG_MAX <<  SCHED_CAPACITY_SHIFT]
+	 * runnable_sum is in [0 : LOAD_AVG_MAX]
+	 */
+	running_sum = se->avg.util_sum >> SCHED_CAPACITY_SHIFT;
+	runnable_sum = max(runnable_sum, running_sum);
+
+	load_sum = se_weight(se) * runnable_sum;
+	load_avg = div_u64(load_sum, divider);
+
+	delta_avg = load_avg - se->avg.load_avg;
+	if (!delta_avg)
+		return;
+
+	delta_sum = load_sum - (s64)se_weight(se) * se->avg.load_sum;
+
+	se->avg.load_sum = runnable_sum;
+	se->avg.load_avg = load_avg;
+	add_positive(&cfs_rq->avg.load_avg, delta_avg);
+	add_positive(&cfs_rq->avg.load_sum, delta_sum);
+	/* See update_cfs_rq_load_avg() */
+	cfs_rq->avg.load_sum = max_t(u32, cfs_rq->avg.load_sum,
+					  cfs_rq->avg.load_avg * PELT_MIN_DIVIDER);
+}
+
+static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum)
+{
+	cfs_rq->propagate = 1;
+	cfs_rq->prop_runnable_sum += runnable_sum;
+}
+
+/* Update task and its cfs_rq load average */
+static inline int propagate_entity_load_avg(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq, *gcfs_rq;
+
+	if (entity_is_task(se))
+		return 0;
+
+	gcfs_rq = group_cfs_rq(se);
+	if (!gcfs_rq->propagate)
+		return 0;
+
+	gcfs_rq->propagate = 0;
+
+	cfs_rq = cfs_rq_of(se);
+
+	add_tg_cfs_propagate(cfs_rq, gcfs_rq->prop_runnable_sum);
+
+	update_tg_cfs_util(cfs_rq, se, gcfs_rq);
+	update_tg_cfs_runnable(cfs_rq, se, gcfs_rq);
+	update_tg_cfs_load(cfs_rq, se, gcfs_rq);
+
+	trace_pelt_cfs_tp(cfs_rq);
+	trace_pelt_se_tp(se);
+
+	return 1;
+}
+
+/*
+ * Check if we need to update the load and the utilization of a blocked
+ * group_entity:
+ */
+static inline bool skip_blocked_update(struct sched_entity *se)
+{
+	struct cfs_rq *gcfs_rq = group_cfs_rq(se);
+
+	/*
+	 * If sched_entity still have not zero load or utilization, we have to
+	 * decay it:
+	 */
+	if (se->avg.load_avg || se->avg.util_avg)
+		return false;
+
+	/*
+	 * If there is a pending propagation, we have to update the load and
+	 * the utilization of the sched_entity:
+	 */
+	if (gcfs_rq->propagate)
+		return false;
+
+	/*
+	 * Otherwise, the load and the utilization of the sched_entity is
+	 * already zero and there is no pending propagation, so it will be a
+	 * waste of time to try to decay it:
+	 */
+	return true;
+}
+
+#else /* CONFIG_FAIR_GROUP_SCHED */
+
+static inline void update_tg_load_avg(struct cfs_rq *cfs_rq) {}
+
+static inline int propagate_entity_load_avg(struct sched_entity *se)
+{
+	return 0;
+}
+
+static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum) {}
+
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+#ifdef CONFIG_NO_HZ_COMMON
+static inline void migrate_se_pelt_lag(struct sched_entity *se)
+{
+	u64 throttled = 0, now, lut;
+	struct cfs_rq *cfs_rq;
+	struct rq *rq;
+	bool is_idle;
+
+	if (load_avg_is_decayed(&se->avg))
+		return;
+
+	cfs_rq = cfs_rq_of(se);
+	rq = rq_of(cfs_rq);
+
+	rcu_read_lock();
+	is_idle = is_idle_task(rcu_dereference(rq->curr));
+	rcu_read_unlock();
+
+	/*
+	 * The lag estimation comes with a cost we don't want to pay all the
+	 * time. Hence, limiting to the case where the source CPU is idle and
+	 * we know we are at the greatest risk to have an outdated clock.
+	 */
+	if (!is_idle)
+		return;
+
+	/*
+	 * Estimated "now" is: last_update_time + cfs_idle_lag + rq_idle_lag, where:
+	 *
+	 *   last_update_time (the cfs_rq's last_update_time)
+	 *	= cfs_rq_clock_pelt()@cfs_rq_idle
+	 *      = rq_clock_pelt()@cfs_rq_idle
+	 *        - cfs->throttled_clock_pelt_time@cfs_rq_idle
+	 *
+	 *   cfs_idle_lag (delta between rq's update and cfs_rq's update)
+	 *      = rq_clock_pelt()@rq_idle - rq_clock_pelt()@cfs_rq_idle
+	 *
+	 *   rq_idle_lag (delta between now and rq's update)
+	 *      = sched_clock_cpu() - rq_clock()@rq_idle
+	 *
+	 * We can then write:
+	 *
+	 *    now = rq_clock_pelt()@rq_idle - cfs->throttled_clock_pelt_time +
+	 *          sched_clock_cpu() - rq_clock()@rq_idle
+	 * Where:
+	 *      rq_clock_pelt()@rq_idle is rq->clock_pelt_idle
+	 *      rq_clock()@rq_idle      is rq->clock_idle
+	 *      cfs->throttled_clock_pelt_time@cfs_rq_idle
+	 *                              is cfs_rq->throttled_pelt_idle
+	 */
+
+#ifdef CONFIG_CFS_BANDWIDTH
+	throttled = u64_u32_load(cfs_rq->throttled_pelt_idle);
+	/* The clock has been stopped for throttling */
+	if (throttled == U64_MAX)
+		return;
+#endif
+	now = u64_u32_load(rq->clock_pelt_idle);
+	/*
+	 * Paired with _update_idle_rq_clock_pelt(). It ensures at the worst case
+	 * is observed the old clock_pelt_idle value and the new clock_idle,
+	 * which lead to an underestimation. The opposite would lead to an
+	 * overestimation.
+	 */
+	smp_rmb();
+	lut = cfs_rq_last_update_time(cfs_rq);
+
+	now -= throttled;
+	if (now < lut)
+		/*
+		 * cfs_rq->avg.last_update_time is more recent than our
+		 * estimation, let's use it.
+		 */
+		now = lut;
+	else
+		now += sched_clock_cpu(cpu_of(rq)) - u64_u32_load(rq->clock_idle);
+
+	__update_load_avg_blocked_se(now, se);
+}
+#else
+static void migrate_se_pelt_lag(struct sched_entity *se) {}
+#endif
+
+/**
+ * update_cfs_rq_load_avg - update the cfs_rq's load/util averages
+ * @now: current time, as per cfs_rq_clock_pelt()
+ * @cfs_rq: cfs_rq to update
+ *
+ * The cfs_rq avg is the direct sum of all its entities (blocked and runnable)
+ * avg. The immediate corollary is that all (fair) tasks must be attached.
+ *
+ * cfs_rq->avg is used for task_h_load() and update_cfs_share() for example.
+ *
+ * Return: true if the load decayed or we removed load.
+ *
+ * Since both these conditions indicate a changed cfs_rq->avg.load we should
+ * call update_tg_load_avg() when this function returns true.
+ */
+static inline int
+update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
+{
+	unsigned long removed_load = 0, removed_util = 0, removed_runnable = 0;
+	struct sched_avg *sa = &cfs_rq->avg;
+	int decayed = 0;
+
+	if (cfs_rq->removed.nr) {
+		unsigned long r;
+		u32 divider = get_pelt_divider(&cfs_rq->avg);
+
+		raw_spin_lock(&cfs_rq->removed.lock);
+		swap(cfs_rq->removed.util_avg, removed_util);
+		swap(cfs_rq->removed.load_avg, removed_load);
+		swap(cfs_rq->removed.runnable_avg, removed_runnable);
+		cfs_rq->removed.nr = 0;
+		raw_spin_unlock(&cfs_rq->removed.lock);
+
+		r = removed_load;
+		sub_positive(&sa->load_avg, r);
+		sub_positive(&sa->load_sum, r * divider);
+		/* See sa->util_sum below */
+		sa->load_sum = max_t(u32, sa->load_sum, sa->load_avg * PELT_MIN_DIVIDER);
+
+		r = removed_util;
+		sub_positive(&sa->util_avg, r);
+		sub_positive(&sa->util_sum, r * divider);
+		/*
+		 * Because of rounding, se->util_sum might ends up being +1 more than
+		 * cfs->util_sum. Although this is not a problem by itself, detaching
+		 * a lot of tasks with the rounding problem between 2 updates of
+		 * util_avg (~1ms) can make cfs->util_sum becoming null whereas
+		 * cfs_util_avg is not.
+		 * Check that util_sum is still above its lower bound for the new
+		 * util_avg. Given that period_contrib might have moved since the last
+		 * sync, we are only sure that util_sum must be above or equal to
+		 *    util_avg * minimum possible divider
+		 */
+		sa->util_sum = max_t(u32, sa->util_sum, sa->util_avg * PELT_MIN_DIVIDER);
+
+		r = removed_runnable;
+		sub_positive(&sa->runnable_avg, r);
+		sub_positive(&sa->runnable_sum, r * divider);
+		/* See sa->util_sum above */
+		sa->runnable_sum = max_t(u32, sa->runnable_sum,
+					      sa->runnable_avg * PELT_MIN_DIVIDER);
+
+		/*
+		 * removed_runnable is the unweighted version of removed_load so we
+		 * can use it to estimate removed_load_sum.
+		 */
+		add_tg_cfs_propagate(cfs_rq,
+			-(long)(removed_runnable * divider) >> SCHED_CAPACITY_SHIFT);
+
+		decayed = 1;
+	}
+
+	decayed |= __update_load_avg_cfs_rq(now, cfs_rq);
+	u64_u32_store_copy(sa->last_update_time,
+			   cfs_rq->last_update_time_copy,
+			   sa->last_update_time);
+	return decayed;
+}
+
+/**
+ * attach_entity_load_avg - attach this entity to its cfs_rq load avg
+ * @cfs_rq: cfs_rq to attach to
+ * @se: sched_entity to attach
+ *
+ * Must call update_cfs_rq_load_avg() before this, since we rely on
+ * cfs_rq->avg.last_update_time being current.
+ */
+static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	/*
+	 * cfs_rq->avg.period_contrib can be used for both cfs_rq and se.
+	 * See ___update_load_avg() for details.
+	 */
+	u32 divider = get_pelt_divider(&cfs_rq->avg);
+
+	/*
+	 * When we attach the @se to the @cfs_rq, we must align the decay
+	 * window because without that, really weird and wonderful things can
+	 * happen.
+	 *
+	 * XXX illustrate
+	 */
+	se->avg.last_update_time = cfs_rq->avg.last_update_time;
+	se->avg.period_contrib = cfs_rq->avg.period_contrib;
+
+	/*
+	 * Hell(o) Nasty stuff.. we need to recompute _sum based on the new
+	 * period_contrib. This isn't strictly correct, but since we're
+	 * entirely outside of the PELT hierarchy, nobody cares if we truncate
+	 * _sum a little.
+	 */
+	se->avg.util_sum = se->avg.util_avg * divider;
+
+	se->avg.runnable_sum = se->avg.runnable_avg * divider;
+
+	se->avg.load_sum = se->avg.load_avg * divider;
+	if (se_weight(se) < se->avg.load_sum)
+		se->avg.load_sum = div_u64(se->avg.load_sum, se_weight(se));
+	else
+		se->avg.load_sum = 1;
+
+	enqueue_load_avg(cfs_rq, se);
+	cfs_rq->avg.util_avg += se->avg.util_avg;
+	cfs_rq->avg.util_sum += se->avg.util_sum;
+	cfs_rq->avg.runnable_avg += se->avg.runnable_avg;
+	cfs_rq->avg.runnable_sum += se->avg.runnable_sum;
+
+	add_tg_cfs_propagate(cfs_rq, se->avg.load_sum);
+
+	cfs_rq_util_change(cfs_rq, 0);
+
+	trace_pelt_cfs_tp(cfs_rq);
+}
+
+/**
+ * detach_entity_load_avg - detach this entity from its cfs_rq load avg
+ * @cfs_rq: cfs_rq to detach from
+ * @se: sched_entity to detach
+ *
+ * Must call update_cfs_rq_load_avg() before this, since we rely on
+ * cfs_rq->avg.last_update_time being current.
+ */
+static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	dequeue_load_avg(cfs_rq, se);
+	sub_positive(&cfs_rq->avg.util_avg, se->avg.util_avg);
+	sub_positive(&cfs_rq->avg.util_sum, se->avg.util_sum);
+	/* See update_cfs_rq_load_avg() */
+	cfs_rq->avg.util_sum = max_t(u32, cfs_rq->avg.util_sum,
+					  cfs_rq->avg.util_avg * PELT_MIN_DIVIDER);
+
+	sub_positive(&cfs_rq->avg.runnable_avg, se->avg.runnable_avg);
+	sub_positive(&cfs_rq->avg.runnable_sum, se->avg.runnable_sum);
+	/* See update_cfs_rq_load_avg() */
+	cfs_rq->avg.runnable_sum = max_t(u32, cfs_rq->avg.runnable_sum,
+					      cfs_rq->avg.runnable_avg * PELT_MIN_DIVIDER);
+
+	add_tg_cfs_propagate(cfs_rq, -se->avg.load_sum);
+
+	cfs_rq_util_change(cfs_rq, 0);
+
+	trace_pelt_cfs_tp(cfs_rq);
+}
+
+/*
+ * Optional action to be done while updating the load average
+ */
+#define UPDATE_TG	0x1
+#define SKIP_AGE_LOAD	0x2
+#define DO_ATTACH	0x4
+#define DO_DETACH	0x8
+
+/* Update task and its cfs_rq load average */
+static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+	u64 now = cfs_rq_clock_pelt(cfs_rq);
+	int decayed;
+
+	/*
+	 * Track task load average for carrying it to new CPU after migrated, and
+	 * track group sched_entity load average for task_h_load calc in migration
+	 */
+	if (se->avg.last_update_time && !(flags & SKIP_AGE_LOAD))
+		__update_load_avg_se(now, cfs_rq, se);
+
+	decayed  = update_cfs_rq_load_avg(now, cfs_rq);
+	decayed |= propagate_entity_load_avg(se);
+
+	if (!se->avg.last_update_time && (flags & DO_ATTACH)) {
+
+		/*
+		 * DO_ATTACH means we're here from enqueue_entity().
+		 * !last_update_time means we've passed through
+		 * migrate_task_rq_fair() indicating we migrated.
+		 *
+		 * IOW we're enqueueing a task on a new CPU.
+		 */
+		attach_entity_load_avg(cfs_rq, se);
+		update_tg_load_avg(cfs_rq);
+
+	} else if (flags & DO_DETACH) {
+		/*
+		 * DO_DETACH means we're here from dequeue_entity()
+		 * and we are migrating task out of the CPU.
+		 */
+		detach_entity_load_avg(cfs_rq, se);
+		update_tg_load_avg(cfs_rq);
+	} else if (decayed) {
+		cfs_rq_util_change(cfs_rq, 0);
+
+		if (flags & UPDATE_TG)
+			update_tg_load_avg(cfs_rq);
+	}
+}
+
+/*
+ * Synchronize entity load avg of dequeued entity without locking
+ * the previous rq.
+ */
+static void sync_entity_load_avg(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+	u64 last_update_time;
+
+	last_update_time = cfs_rq_last_update_time(cfs_rq);
+	__update_load_avg_blocked_se(last_update_time, se);
+}
+
+/*
+ * Task first catches up with cfs_rq, and then subtract
+ * itself from the cfs_rq (task must be off the queue now).
+ */
+static void remove_entity_load_avg(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+	unsigned long flags;
+
+	/*
+	 * tasks cannot exit without having gone through wake_up_new_task() ->
+	 * enqueue_task_fair() which will have added things to the cfs_rq,
+	 * so we can remove unconditionally.
+	 */
+
+	sync_entity_load_avg(se);
+
+	raw_spin_lock_irqsave(&cfs_rq->removed.lock, flags);
+	++cfs_rq->removed.nr;
+	cfs_rq->removed.util_avg	+= se->avg.util_avg;
+	cfs_rq->removed.load_avg	+= se->avg.load_avg;
+	cfs_rq->removed.runnable_avg	+= se->avg.runnable_avg;
+	raw_spin_unlock_irqrestore(&cfs_rq->removed.lock, flags);
+}
+
+static inline unsigned long cfs_rq_runnable_avg(struct cfs_rq *cfs_rq)
+{
+	return cfs_rq->avg.runnable_avg;
+}
+
+static inline unsigned long cfs_rq_load_avg(struct cfs_rq *cfs_rq)
+{
+	return cfs_rq->avg.load_avg;
+}
+
+static int newidle_balance(struct rq *this_rq, struct rq_flags *rf);
+
+static inline unsigned long task_util(struct task_struct *p)
+{
+	return READ_ONCE(p->se.avg.util_avg);
+}
+
+static inline unsigned long _task_util_est(struct task_struct *p)
+{
+	struct util_est ue = READ_ONCE(p->se.avg.util_est);
+
+	return max(ue.ewma, (ue.enqueued & ~UTIL_AVG_UNCHANGED));
+}
+
+static inline unsigned long task_util_est(struct task_struct *p)
+{
+	return max(task_util(p), _task_util_est(p));
+}
+
+static inline void util_est_enqueue(struct cfs_rq *cfs_rq,
+				    struct task_struct *p)
+{
+	unsigned int enqueued;
+
+	if (!sched_feat(UTIL_EST))
+		return;
+
+	/* Update root cfs_rq's estimated utilization */
+	enqueued  = cfs_rq->avg.util_est.enqueued;
+	enqueued += _task_util_est(p);
+	WRITE_ONCE(cfs_rq->avg.util_est.enqueued, enqueued);
+
+	trace_sched_util_est_cfs_tp(cfs_rq);
+}
+
+static inline void util_est_dequeue(struct cfs_rq *cfs_rq,
+				    struct task_struct *p)
+{
+	unsigned int enqueued;
+
+	if (!sched_feat(UTIL_EST))
+		return;
+
+	/* Update root cfs_rq's estimated utilization */
+	enqueued  = cfs_rq->avg.util_est.enqueued;
+	enqueued -= min_t(unsigned int, enqueued, _task_util_est(p));
+	WRITE_ONCE(cfs_rq->avg.util_est.enqueued, enqueued);
+
+	trace_sched_util_est_cfs_tp(cfs_rq);
+}
+
+#define UTIL_EST_MARGIN (SCHED_CAPACITY_SCALE / 100)
+
+/*
+ * Check if a (signed) value is within a specified (unsigned) margin,
+ * based on the observation that:
+ *
+ *     abs(x) < y := (unsigned)(x + y - 1) < (2 * y - 1)
+ *
+ * NOTE: this only works when value + margin < INT_MAX.
+ */
+static inline bool within_margin(int value, int margin)
+{
+	return ((unsigned int)(value + margin - 1) < (2 * margin - 1));
+}
+
+static inline void util_est_update(struct cfs_rq *cfs_rq,
+				   struct task_struct *p,
+				   bool task_sleep)
+{
+	long last_ewma_diff, last_enqueued_diff;
+	struct util_est ue;
+
+	if (!sched_feat(UTIL_EST))
+		return;
+
+	/*
+	 * Skip update of task's estimated utilization when the task has not
+	 * yet completed an activation, e.g. being migrated.
+	 */
+	if (!task_sleep)
+		return;
+
+	/*
+	 * If the PELT values haven't changed since enqueue time,
+	 * skip the util_est update.
+	 */
+	ue = p->se.avg.util_est;
+	if (ue.enqueued & UTIL_AVG_UNCHANGED)
+		return;
+
+	last_enqueued_diff = ue.enqueued;
+
+	/*
+	 * Reset EWMA on utilization increases, the moving average is used only
+	 * to smooth utilization decreases.
+	 */
+	ue.enqueued = task_util(p);
+	if (sched_feat(UTIL_EST_FASTUP)) {
+		if (ue.ewma < ue.enqueued) {
+			ue.ewma = ue.enqueued;
+			goto done;
+		}
+	}
+
+	/*
+	 * Skip update of task's estimated utilization when its members are
+	 * already ~1% close to its last activation value.
+	 */
+	last_ewma_diff = ue.enqueued - ue.ewma;
+	last_enqueued_diff -= ue.enqueued;
+	if (within_margin(last_ewma_diff, UTIL_EST_MARGIN)) {
+		if (!within_margin(last_enqueued_diff, UTIL_EST_MARGIN))
+			goto done;
+
+		return;
+	}
+
+	/*
+	 * To avoid overestimation of actual task utilization, skip updates if
+	 * we cannot grant there is idle time in this CPU.
+	 */
+	if (task_util(p) > capacity_orig_of(cpu_of(rq_of(cfs_rq))))
+		return;
+
+	/*
+	 * Update Task's estimated utilization
+	 *
+	 * When *p completes an activation we can consolidate another sample
+	 * of the task size. This is done by storing the current PELT value
+	 * as ue.enqueued and by using this value to update the Exponential
+	 * Weighted Moving Average (EWMA):
+	 *
+	 *  ewma(t) = w *  task_util(p) + (1-w) * ewma(t-1)
+	 *          = w *  task_util(p) +         ewma(t-1)  - w * ewma(t-1)
+	 *          = w * (task_util(p) -         ewma(t-1)) +     ewma(t-1)
+	 *          = w * (      last_ewma_diff            ) +     ewma(t-1)
+	 *          = w * (last_ewma_diff  +  ewma(t-1) / w)
+	 *
+	 * Where 'w' is the weight of new samples, which is configured to be
+	 * 0.25, thus making w=1/4 ( >>= UTIL_EST_WEIGHT_SHIFT)
+	 */
+	ue.ewma <<= UTIL_EST_WEIGHT_SHIFT;
+	ue.ewma  += last_ewma_diff;
+	ue.ewma >>= UTIL_EST_WEIGHT_SHIFT;
+done:
+	ue.enqueued |= UTIL_AVG_UNCHANGED;
+	WRITE_ONCE(p->se.avg.util_est, ue);
+
+	trace_sched_util_est_se_tp(&p->se);
+}
+
+static inline int util_fits_cpu(unsigned long util,
+				unsigned long uclamp_min,
+				unsigned long uclamp_max,
+				int cpu)
+{
+	unsigned long capacity_orig, capacity_orig_thermal;
+	unsigned long capacity = capacity_of(cpu);
+	bool fits, uclamp_max_fits;
+
+	/*
+	 * Check if the real util fits without any uclamp boost/cap applied.
+	 */
+	fits = fits_capacity(util, capacity);
+
+	if (!uclamp_is_used())
+		return fits;
+
+	/*
+	 * We must use capacity_orig_of() for comparing against uclamp_min and
+	 * uclamp_max. We only care about capacity pressure (by using
+	 * capacity_of()) for comparing against the real util.
+	 *
+	 * If a task is boosted to 1024 for example, we don't want a tiny
+	 * pressure to skew the check whether it fits a CPU or not.
+	 *
+	 * Similarly if a task is capped to capacity_orig_of(little_cpu), it
+	 * should fit a little cpu even if there's some pressure.
+	 *
+	 * Only exception is for thermal pressure since it has a direct impact
+	 * on available OPP of the system.
+	 *
+	 * We honour it for uclamp_min only as a drop in performance level
+	 * could result in not getting the requested minimum performance level.
+	 *
+	 * For uclamp_max, we can tolerate a drop in performance level as the
+	 * goal is to cap the task. So it's okay if it's getting less.
+	 */
+	capacity_orig = capacity_orig_of(cpu);
+	capacity_orig_thermal = capacity_orig - arch_scale_thermal_pressure(cpu);
+
+	/*
+	 * We want to force a task to fit a cpu as implied by uclamp_max.
+	 * But we do have some corner cases to cater for..
+	 *
+	 *
+	 *                                 C=z
+	 *   |                             ___
+	 *   |                  C=y       |   |
+	 *   |_ _ _ _ _ _ _ _ _ ___ _ _ _ | _ | _ _ _ _ _  uclamp_max
+	 *   |      C=x        |   |      |   |
+	 *   |      ___        |   |      |   |
+	 *   |     |   |       |   |      |   |    (util somewhere in this region)
+	 *   |     |   |       |   |      |   |
+	 *   |     |   |       |   |      |   |
+	 *   +----------------------------------------
+	 *         cpu0        cpu1       cpu2
+	 *
+	 *   In the above example if a task is capped to a specific performance
+	 *   point, y, then when:
+	 *
+	 *   * util = 80% of x then it does not fit on cpu0 and should migrate
+	 *     to cpu1
+	 *   * util = 80% of y then it is forced to fit on cpu1 to honour
+	 *     uclamp_max request.
+	 *
+	 *   which is what we're enforcing here. A task always fits if
+	 *   uclamp_max <= capacity_orig. But when uclamp_max > capacity_orig,
+	 *   the normal upmigration rules should withhold still.
+	 *
+	 *   Only exception is when we are on max capacity, then we need to be
+	 *   careful not to block overutilized state. This is so because:
+	 *
+	 *     1. There's no concept of capping at max_capacity! We can't go
+	 *        beyond this performance level anyway.
+	 *     2. The system is being saturated when we're operating near
+	 *        max capacity, it doesn't make sense to block overutilized.
+	 */
+	uclamp_max_fits = (capacity_orig == SCHED_CAPACITY_SCALE) && (uclamp_max == SCHED_CAPACITY_SCALE);
+	uclamp_max_fits = !uclamp_max_fits && (uclamp_max <= capacity_orig);
+	fits = fits || uclamp_max_fits;
+
+	/*
+	 *
+	 *                                 C=z
+	 *   |                             ___       (region a, capped, util >= uclamp_max)
+	 *   |                  C=y       |   |
+	 *   |_ _ _ _ _ _ _ _ _ ___ _ _ _ | _ | _ _ _ _ _ uclamp_max
+	 *   |      C=x        |   |      |   |
+	 *   |      ___        |   |      |   |      (region b, uclamp_min <= util <= uclamp_max)
+	 *   |_ _ _|_ _|_ _ _ _| _ | _ _ _| _ | _ _ _ _ _ uclamp_min
+	 *   |     |   |       |   |      |   |
+	 *   |     |   |       |   |      |   |      (region c, boosted, util < uclamp_min)
+	 *   +----------------------------------------
+	 *         cpu0        cpu1       cpu2
+	 *
+	 * a) If util > uclamp_max, then we're capped, we don't care about
+	 *    actual fitness value here. We only care if uclamp_max fits
+	 *    capacity without taking margin/pressure into account.
+	 *    See comment above.
+	 *
+	 * b) If uclamp_min <= util <= uclamp_max, then the normal
+	 *    fits_capacity() rules apply. Except we need to ensure that we
+	 *    enforce we remain within uclamp_max, see comment above.
+	 *
+	 * c) If util < uclamp_min, then we are boosted. Same as (b) but we
+	 *    need to take into account the boosted value fits the CPU without
+	 *    taking margin/pressure into account.
+	 *
+	 * Cases (a) and (b) are handled in the 'fits' variable already. We
+	 * just need to consider an extra check for case (c) after ensuring we
+	 * handle the case uclamp_min > uclamp_max.
+	 */
+	uclamp_min = min(uclamp_min, uclamp_max);
+	if (fits && (util < uclamp_min) && (uclamp_min > capacity_orig_thermal))
+		return -1;
+
+	return fits;
+}
+
+static inline int task_fits_cpu(struct task_struct *p, int cpu)
+{
+	unsigned long uclamp_min = uclamp_eff_value(p, UCLAMP_MIN);
+	unsigned long uclamp_max = uclamp_eff_value(p, UCLAMP_MAX);
+	unsigned long util = task_util_est(p);
+	/*
+	 * Return true only if the cpu fully fits the task requirements, which
+	 * include the utilization but also the performance hints.
+	 */
+	return (util_fits_cpu(util, uclamp_min, uclamp_max, cpu) > 0);
+}
+
+static inline void update_misfit_status(struct task_struct *p, struct rq *rq)
+{
+	if (!sched_asym_cpucap_active())
+		return;
+
+	if (!p || p->nr_cpus_allowed == 1) {
+		rq->misfit_task_load = 0;
+		return;
+	}
+
+	if (task_fits_cpu(p, cpu_of(rq))) {
+		rq->misfit_task_load = 0;
+		return;
+	}
+
+	/*
+	 * Make sure that misfit_task_load will not be null even if
+	 * task_h_load() returns 0.
+	 */
+	rq->misfit_task_load = max_t(unsigned long, task_h_load(p), 1);
+}
+
+#else /* CONFIG_SMP */
+
+static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
+{
+	return !cfs_rq->nr_running;
+}
+
+#define UPDATE_TG	0x0
+#define SKIP_AGE_LOAD	0x0
+#define DO_ATTACH	0x0
+#define DO_DETACH	0x0
+
+static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1)
+{
+	cfs_rq_util_change(cfs_rq, 0);
+}
+
+static inline void remove_entity_load_avg(struct sched_entity *se) {}
+
+static inline void
+attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
+static inline void
+detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
+
+static inline int newidle_balance(struct rq *rq, struct rq_flags *rf)
+{
+	return 0;
+}
+
+static inline void
+util_est_enqueue(struct cfs_rq *cfs_rq, struct task_struct *p) {}
+
+static inline void
+util_est_dequeue(struct cfs_rq *cfs_rq, struct task_struct *p) {}
+
+static inline void
+util_est_update(struct cfs_rq *cfs_rq, struct task_struct *p,
+		bool task_sleep) {}
+static inline void update_misfit_status(struct task_struct *p, struct rq *rq) {}
+
+#endif /* CONFIG_SMP */
+
+static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+#ifdef CONFIG_SCHED_DEBUG
+	s64 d = se->vruntime - cfs_rq->min_vruntime;
+
+	if (d < 0)
+		d = -d;
+
+	if (d > 3*sysctl_sched_latency)
+		schedstat_inc(cfs_rq->nr_spread_over);
+#endif
+}
+
+static inline bool entity_is_long_sleeper(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq;
+	u64 sleep_time;
+
+	if (se->exec_start == 0)
+		return false;
+
+	cfs_rq = cfs_rq_of(se);
+
+	sleep_time = rq_clock_task(rq_of(cfs_rq));
+
+	/* Happen while migrating because of clock task divergence */
+	if (sleep_time <= se->exec_start)
+		return false;
+
+	sleep_time -= se->exec_start;
+	if (sleep_time > ((1ULL << 63) / scale_load_down(NICE_0_LOAD)))
+		return true;
+
+	return false;
+}
+
+static void
+place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
+{
+	u64 vruntime = cfs_rq->min_vruntime;
+
+	/*
+	 * The 'current' period is already promised to the current tasks,
+	 * however the extra weight of the new task will slow them down a
+	 * little, place the new task so that it fits in the slot that
+	 * stays open at the end.
+	 */
+	if (initial && sched_feat(START_DEBIT))
+		vruntime += sched_vslice(cfs_rq, se);
+
+	/* sleeps up to a single latency don't count. */
+	if (!initial) {
+		unsigned long thresh;
+
+		if (se_is_idle(se))
+			thresh = sysctl_sched_min_granularity;
+		else
+			thresh = sysctl_sched_latency;
+
+		/*
+		 * Halve their sleep time's effect, to allow
+		 * for a gentler effect of sleepers:
+		 */
+		if (sched_feat(GENTLE_FAIR_SLEEPERS))
+			thresh >>= 1;
+
+		vruntime -= thresh;
+	}
+
+	/*
+	 * Pull vruntime of the entity being placed to the base level of
+	 * cfs_rq, to prevent boosting it if placed backwards.
+	 * However, min_vruntime can advance much faster than real time, with
+	 * the extreme being when an entity with the minimal weight always runs
+	 * on the cfs_rq. If the waking entity slept for a long time, its
+	 * vruntime difference from min_vruntime may overflow s64 and their
+	 * comparison may get inversed, so ignore the entity's original
+	 * vruntime in that case.
+	 * The maximal vruntime speedup is given by the ratio of normal to
+	 * minimal weight: scale_load_down(NICE_0_LOAD) / MIN_SHARES.
+	 * When placing a migrated waking entity, its exec_start has been set
+	 * from a different rq. In order to take into account a possible
+	 * divergence between new and prev rq's clocks task because of irq and
+	 * stolen time, we take an additional margin.
+	 * So, cutting off on the sleep time of
+	 *     2^63 / scale_load_down(NICE_0_LOAD) ~ 104 days
+	 * should be safe.
+	 */
+	if (entity_is_long_sleeper(se))
+		se->vruntime = vruntime;
+	else
+		se->vruntime = max_vruntime(se->vruntime, vruntime);
+}
+
+static void check_enqueue_throttle(struct cfs_rq *cfs_rq);
+
+static inline bool cfs_bandwidth_used(void);
+
+/*
+ * MIGRATION
+ *
+ *	dequeue
+ *	  update_curr()
+ *	    update_min_vruntime()
+ *	  vruntime -= min_vruntime
+ *
+ *	enqueue
+ *	  update_curr()
+ *	    update_min_vruntime()
+ *	  vruntime += min_vruntime
+ *
+ * this way the vruntime transition between RQs is done when both
+ * min_vruntime are up-to-date.
+ *
+ * WAKEUP (remote)
+ *
+ *	->migrate_task_rq_fair() (p->state == TASK_WAKING)
+ *	  vruntime -= min_vruntime
+ *
+ *	enqueue
+ *	  update_curr()
+ *	    update_min_vruntime()
+ *	  vruntime += min_vruntime
+ *
+ * this way we don't have the most up-to-date min_vruntime on the originating
+ * CPU and an up-to-date min_vruntime on the destination CPU.
+ */
+
+static void
+enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+	bool renorm = !(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_MIGRATED);
+	bool curr = cfs_rq->curr == se;
+
+	/*
+	 * If we're the current task, we must renormalise before calling
+	 * update_curr().
+	 */
+	if (renorm && curr)
+		se->vruntime += cfs_rq->min_vruntime;
+
+	update_curr(cfs_rq);
+
+	/*
+	 * Otherwise, renormalise after, such that we're placed at the current
+	 * moment in time, instead of some random moment in the past. Being
+	 * placed in the past could significantly boost this task to the
+	 * fairness detriment of existing tasks.
+	 */
+	if (renorm && !curr)
+		se->vruntime += cfs_rq->min_vruntime;
+
+	/*
+	 * When enqueuing a sched_entity, we must:
+	 *   - Update loads to have both entity and cfs_rq synced with now.
+	 *   - For group_entity, update its runnable_weight to reflect the new
+	 *     h_nr_running of its group cfs_rq.
+	 *   - For group_entity, update its weight to reflect the new share of
+	 *     its group cfs_rq
+	 *   - Add its new weight to cfs_rq->load.weight
+	 */
+	update_load_avg(cfs_rq, se, UPDATE_TG | DO_ATTACH);
+	se_update_runnable(se);
+	update_cfs_group(se);
+	account_entity_enqueue(cfs_rq, se);
+
+	if (flags & ENQUEUE_WAKEUP)
+		place_entity(cfs_rq, se, 0);
+	/* Entity has migrated, no longer consider this task hot */
+	if (flags & ENQUEUE_MIGRATED)
+		se->exec_start = 0;
+
+	check_schedstat_required();
+	update_stats_enqueue_fair(cfs_rq, se, flags);
+	check_spread(cfs_rq, se);
+	if (!curr)
+		__enqueue_entity(cfs_rq, se);
+	se->on_rq = 1;
+
+	if (cfs_rq->nr_running == 1) {
+		check_enqueue_throttle(cfs_rq);
+		if (!throttled_hierarchy(cfs_rq))
+			list_add_leaf_cfs_rq(cfs_rq);
+	}
+}
+
+static void __clear_buddies_last(struct sched_entity *se)
+{
+	for_each_sched_entity(se) {
+		struct cfs_rq *cfs_rq = cfs_rq_of(se);
+		if (cfs_rq->last != se)
+			break;
+
+		cfs_rq->last = NULL;
+	}
+}
+
+static void __clear_buddies_next(struct sched_entity *se)
+{
+	for_each_sched_entity(se) {
+		struct cfs_rq *cfs_rq = cfs_rq_of(se);
+		if (cfs_rq->next != se)
+			break;
+
+		cfs_rq->next = NULL;
+	}
+}
+
+static void __clear_buddies_skip(struct sched_entity *se)
+{
+	for_each_sched_entity(se) {
+		struct cfs_rq *cfs_rq = cfs_rq_of(se);
+		if (cfs_rq->skip != se)
+			break;
+
+		cfs_rq->skip = NULL;
+	}
+}
+
+static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	if (cfs_rq->last == se)
+		__clear_buddies_last(se);
+
+	if (cfs_rq->next == se)
+		__clear_buddies_next(se);
+
+	if (cfs_rq->skip == se)
+		__clear_buddies_skip(se);
+}
+
+static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq);
+
+static void
+dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+{
+	int action = UPDATE_TG;
+
+	if (entity_is_task(se) && task_on_rq_migrating(task_of(se)))
+		action |= DO_DETACH;
+
+	/*
+	 * Update run-time statistics of the 'current'.
+	 */
+	update_curr(cfs_rq);
+
+	/*
+	 * When dequeuing a sched_entity, we must:
+	 *   - Update loads to have both entity and cfs_rq synced with now.
+	 *   - For group_entity, update its runnable_weight to reflect the new
+	 *     h_nr_running of its group cfs_rq.
+	 *   - Subtract its previous weight from cfs_rq->load.weight.
+	 *   - For group entity, update its weight to reflect the new share
+	 *     of its group cfs_rq.
+	 */
+	update_load_avg(cfs_rq, se, action);
+	se_update_runnable(se);
+
+	update_stats_dequeue_fair(cfs_rq, se, flags);
+
+	clear_buddies(cfs_rq, se);
+
+	if (se != cfs_rq->curr)
+		__dequeue_entity(cfs_rq, se);
+	se->on_rq = 0;
+	account_entity_dequeue(cfs_rq, se);
+
+	/*
+	 * Normalize after update_curr(); which will also have moved
+	 * min_vruntime if @se is the one holding it back. But before doing
+	 * update_min_vruntime() again, which will discount @se's position and
+	 * can move min_vruntime forward still more.
+	 */
+	if (!(flags & DEQUEUE_SLEEP))
+		se->vruntime -= cfs_rq->min_vruntime;
+
+	/* return excess runtime on last dequeue */
+	return_cfs_rq_runtime(cfs_rq);
+
+	update_cfs_group(se);
+
+	/*
+	 * Now advance min_vruntime if @se was the entity holding it back,
+	 * except when: DEQUEUE_SAVE && !DEQUEUE_MOVE, in this case we'll be
+	 * put back on, and if we advance min_vruntime, we'll be placed back
+	 * further than we started -- ie. we'll be penalized.
+	 */
+	if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) != DEQUEUE_SAVE)
+		update_min_vruntime(cfs_rq);
+
+	if (cfs_rq->nr_running == 0)
+		update_idle_cfs_rq_clock_pelt(cfs_rq);
+}
+
+/*
+ * Preempt the current task with a newly woken task if needed:
+ */
+static void
+check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
+{
+	unsigned long ideal_runtime, delta_exec;
+	struct sched_entity *se;
+	s64 delta;
+
+	ideal_runtime = sched_slice(cfs_rq, curr);
+	delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
+	if (delta_exec > ideal_runtime) {
+		resched_curr(rq_of(cfs_rq));
+		/*
+		 * The current task ran long enough, ensure it doesn't get
+		 * re-elected due to buddy favours.
+		 */
+		clear_buddies(cfs_rq, curr);
+		return;
+	}
+
+	/*
+	 * Ensure that a task that missed wakeup preemption by a
+	 * narrow margin doesn't have to wait for a full slice.
+	 * This also mitigates buddy induced latencies under load.
+	 */
+	if (delta_exec < sysctl_sched_min_granularity)
+		return;
+
+	se = __pick_first_entity(cfs_rq);
+	delta = curr->vruntime - se->vruntime;
+
+	if (delta < 0)
+		return;
+
+	if (delta > ideal_runtime)
+		resched_curr(rq_of(cfs_rq));
+}
+
+static void
+set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	clear_buddies(cfs_rq, se);
+
+	/* 'current' is not kept within the tree. */
+	if (se->on_rq) {
+		/*
+		 * Any task has to be enqueued before it get to execute on
+		 * a CPU. So account for the time it spent waiting on the
+		 * runqueue.
+		 */
+		update_stats_wait_end_fair(cfs_rq, se);
+		__dequeue_entity(cfs_rq, se);
+		update_load_avg(cfs_rq, se, UPDATE_TG);
+	}
+
+	update_stats_curr_start(cfs_rq, se);
+	cfs_rq->curr = se;
+
+	/*
+	 * Track our maximum slice length, if the CPU's load is at
+	 * least twice that of our own weight (i.e. dont track it
+	 * when there are only lesser-weight tasks around):
+	 */
+	if (schedstat_enabled() &&
+	    rq_of(cfs_rq)->cfs.load.weight >= 2*se->load.weight) {
+		struct sched_statistics *stats;
+
+		stats = __schedstats_from_se(se);
+		__schedstat_set(stats->slice_max,
+				max((u64)stats->slice_max,
+				    se->sum_exec_runtime - se->prev_sum_exec_runtime));
+	}
+
+	se->prev_sum_exec_runtime = se->sum_exec_runtime;
+}
+
+static int
+wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se);
+
+/*
+ * Pick the next process, keeping these things in mind, in this order:
+ * 1) keep things fair between processes/task groups
+ * 2) pick the "next" process, since someone really wants that to run
+ * 3) pick the "last" process, for cache locality
+ * 4) do not run the "skip" process, if something else is available
+ */
+static struct sched_entity *
+pick_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *curr)
+{
+	struct sched_entity *left = __pick_first_entity(cfs_rq);
+	struct sched_entity *se;
+
+	/*
+	 * If curr is set we have to see if its left of the leftmost entity
+	 * still in the tree, provided there was anything in the tree at all.
+	 */
+	if (!left || (curr && entity_before(curr, left)))
+		left = curr;
+
+	se = left; /* ideally we run the leftmost entity */
+
+	/*
+	 * Avoid running the skip buddy, if running something else can
+	 * be done without getting too unfair.
+	 */
+	if (cfs_rq->skip && cfs_rq->skip == se) {
+		struct sched_entity *second;
+
+		if (se == curr) {
+			second = __pick_first_entity(cfs_rq);
+		} else {
+			second = __pick_next_entity(se);
+			if (!second || (curr && entity_before(curr, second)))
+				second = curr;
+		}
+
+		if (second && wakeup_preempt_entity(second, left) < 1)
+			se = second;
+	}
+
+	if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) {
+		/*
+		 * Someone really wants this to run. If it's not unfair, run it.
+		 */
+		se = cfs_rq->next;
+	} else if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1) {
+		/*
+		 * Prefer last buddy, try to return the CPU to a preempted task.
+		 */
+		se = cfs_rq->last;
+	}
+
+	return se;
+}
+
+static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq);
+
+static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
+{
+	/*
+	 * If still on the runqueue then deactivate_task()
+	 * was not called and update_curr() has to be done:
+	 */
+	if (prev->on_rq)
+		update_curr(cfs_rq);
+
+	/* throttle cfs_rqs exceeding runtime */
+	check_cfs_rq_runtime(cfs_rq);
+
+	check_spread(cfs_rq, prev);
+
+	if (prev->on_rq) {
+		update_stats_wait_start_fair(cfs_rq, prev);
+		/* Put 'current' back into the tree. */
+		__enqueue_entity(cfs_rq, prev);
+		/* in !on_rq case, update occurred at dequeue */
+		update_load_avg(cfs_rq, prev, 0);
+	}
+	cfs_rq->curr = NULL;
+}
+
+static void
+entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
+{
+	/*
+	 * Update run-time statistics of the 'current'.
+	 */
+	update_curr(cfs_rq);
+
+	/*
+	 * Ensure that runnable average is periodically updated.
+	 */
+	update_load_avg(cfs_rq, curr, UPDATE_TG);
+	update_cfs_group(curr);
+
+#ifdef CONFIG_SCHED_HRTICK
+	/*
+	 * queued ticks are scheduled to match the slice, so don't bother
+	 * validating it and just reschedule.
+	 */
+	if (queued) {
+		resched_curr(rq_of(cfs_rq));
+		return;
+	}
+	/*
+	 * don't let the period tick interfere with the hrtick preemption
+	 */
+	if (!sched_feat(DOUBLE_TICK) &&
+			hrtimer_active(&rq_of(cfs_rq)->hrtick_timer))
+		return;
+#endif
+
+	if (cfs_rq->nr_running > 1)
+		check_preempt_tick(cfs_rq, curr);
+}
+
+
+/**************************************************
+ * CFS bandwidth control machinery
+ */
+
+#ifdef CONFIG_CFS_BANDWIDTH
+
+#ifdef CONFIG_JUMP_LABEL
+static struct static_key __cfs_bandwidth_used;
+
+static inline bool cfs_bandwidth_used(void)
+{
+	return static_key_false(&__cfs_bandwidth_used);
+}
+
+void cfs_bandwidth_usage_inc(void)
+{
+	static_key_slow_inc_cpuslocked(&__cfs_bandwidth_used);
+}
+
+void cfs_bandwidth_usage_dec(void)
+{
+	static_key_slow_dec_cpuslocked(&__cfs_bandwidth_used);
+}
+#else /* CONFIG_JUMP_LABEL */
+static bool cfs_bandwidth_used(void)
+{
+	return true;
+}
+
+void cfs_bandwidth_usage_inc(void) {}
+void cfs_bandwidth_usage_dec(void) {}
+#endif /* CONFIG_JUMP_LABEL */
+
+/*
+ * default period for cfs group bandwidth.
+ * default: 0.1s, units: nanoseconds
+ */
+static inline u64 default_cfs_period(void)
+{
+	return 100000000ULL;
+}
+
+static inline u64 sched_cfs_bandwidth_slice(void)
+{
+	return (u64)sysctl_sched_cfs_bandwidth_slice * NSEC_PER_USEC;
+}
+
+/*
+ * Replenish runtime according to assigned quota. We use sched_clock_cpu
+ * directly instead of rq->clock to avoid adding additional synchronization
+ * around rq->lock.
+ *
+ * requires cfs_b->lock
+ */
+void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b)
+{
+	s64 runtime;
+
+	if (unlikely(cfs_b->quota == RUNTIME_INF))
+		return;
+
+	cfs_b->runtime += cfs_b->quota;
+	runtime = cfs_b->runtime_snap - cfs_b->runtime;
+	if (runtime > 0) {
+		cfs_b->burst_time += runtime;
+		cfs_b->nr_burst++;
+	}
+
+	cfs_b->runtime = min(cfs_b->runtime, cfs_b->quota + cfs_b->burst);
+	cfs_b->runtime_snap = cfs_b->runtime;
+}
+
+static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
+{
+	return &tg->cfs_bandwidth;
+}
+
+/* returns 0 on failure to allocate runtime */
+static int __assign_cfs_rq_runtime(struct cfs_bandwidth *cfs_b,
+				   struct cfs_rq *cfs_rq, u64 target_runtime)
+{
+	u64 min_amount, amount = 0;
+
+	lockdep_assert_held(&cfs_b->lock);
+
+	/* note: this is a positive sum as runtime_remaining <= 0 */
+	min_amount = target_runtime - cfs_rq->runtime_remaining;
+
+	if (cfs_b->quota == RUNTIME_INF)
+		amount = min_amount;
+	else {
+		start_cfs_bandwidth(cfs_b);
+
+		if (cfs_b->runtime > 0) {
+			amount = min(cfs_b->runtime, min_amount);
+			cfs_b->runtime -= amount;
+			cfs_b->idle = 0;
+		}
+	}
+
+	cfs_rq->runtime_remaining += amount;
+
+	return cfs_rq->runtime_remaining > 0;
+}
+
+/* returns 0 on failure to allocate runtime */
+static int assign_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+	struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+	int ret;
+
+	raw_spin_lock(&cfs_b->lock);
+	ret = __assign_cfs_rq_runtime(cfs_b, cfs_rq, sched_cfs_bandwidth_slice());
+	raw_spin_unlock(&cfs_b->lock);
+
+	return ret;
+}
+
+static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec)
+{
+	/* dock delta_exec before expiring quota (as it could span periods) */
+	cfs_rq->runtime_remaining -= delta_exec;
+
+	if (likely(cfs_rq->runtime_remaining > 0))
+		return;
+
+	if (cfs_rq->throttled)
+		return;
+	/*
+	 * if we're unable to extend our runtime we resched so that the active
+	 * hierarchy can be throttled
+	 */
+	if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr))
+		resched_curr(rq_of(cfs_rq));
+}
+
+static __always_inline
+void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec)
+{
+	if (!cfs_bandwidth_used() || !cfs_rq->runtime_enabled)
+		return;
+
+	__account_cfs_rq_runtime(cfs_rq, delta_exec);
+}
+
+static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq)
+{
+	return cfs_bandwidth_used() && cfs_rq->throttled;
+}
+
+/* check whether cfs_rq, or any parent, is throttled */
+static inline int throttled_hierarchy(struct cfs_rq *cfs_rq)
+{
+	return cfs_bandwidth_used() && cfs_rq->throttle_count;
+}
+
+/*
+ * Ensure that neither of the group entities corresponding to src_cpu or
+ * dest_cpu are members of a throttled hierarchy when performing group
+ * load-balance operations.
+ */
+static inline int throttled_lb_pair(struct task_group *tg,
+				    int src_cpu, int dest_cpu)
+{
+	struct cfs_rq *src_cfs_rq, *dest_cfs_rq;
+
+	src_cfs_rq = tg->cfs_rq[src_cpu];
+	dest_cfs_rq = tg->cfs_rq[dest_cpu];
+
+	return throttled_hierarchy(src_cfs_rq) ||
+	       throttled_hierarchy(dest_cfs_rq);
+}
+
+static int tg_unthrottle_up(struct task_group *tg, void *data)
+{
+	struct rq *rq = data;
+	struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+	cfs_rq->throttle_count--;
+	if (!cfs_rq->throttle_count) {
+		cfs_rq->throttled_clock_pelt_time += rq_clock_pelt(rq) -
+					     cfs_rq->throttled_clock_pelt;
+
+		/* Add cfs_rq with load or one or more already running entities to the list */
+		if (!cfs_rq_is_decayed(cfs_rq))
+			list_add_leaf_cfs_rq(cfs_rq);
+	}
+
+	return 0;
+}
+
+static int tg_throttle_down(struct task_group *tg, void *data)
+{
+	struct rq *rq = data;
+	struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+	/* group is entering throttled state, stop time */
+	if (!cfs_rq->throttle_count) {
+		cfs_rq->throttled_clock_pelt = rq_clock_pelt(rq);
+		list_del_leaf_cfs_rq(cfs_rq);
+	}
+	cfs_rq->throttle_count++;
+
+	return 0;
+}
+
+static bool throttle_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	struct rq *rq = rq_of(cfs_rq);
+	struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+	struct sched_entity *se;
+	long task_delta, idle_task_delta, dequeue = 1;
+
+	raw_spin_lock(&cfs_b->lock);
+	/* This will start the period timer if necessary */
+	if (__assign_cfs_rq_runtime(cfs_b, cfs_rq, 1)) {
+		/*
+		 * We have raced with bandwidth becoming available, and if we
+		 * actually throttled the timer might not unthrottle us for an
+		 * entire period. We additionally needed to make sure that any
+		 * subsequent check_cfs_rq_runtime calls agree not to throttle
+		 * us, as we may commit to do cfs put_prev+pick_next, so we ask
+		 * for 1ns of runtime rather than just check cfs_b.
+		 */
+		dequeue = 0;
+	} else {
+		list_add_tail_rcu(&cfs_rq->throttled_list,
+				  &cfs_b->throttled_cfs_rq);
+	}
+	raw_spin_unlock(&cfs_b->lock);
+
+	if (!dequeue)
+		return false;  /* Throttle no longer required. */
+
+	se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))];
+
+	/* freeze hierarchy runnable averages while throttled */
+	rcu_read_lock();
+	walk_tg_tree_from(cfs_rq->tg, tg_throttle_down, tg_nop, (void *)rq);
+	rcu_read_unlock();
+
+	task_delta = cfs_rq->h_nr_running;
+	idle_task_delta = cfs_rq->idle_h_nr_running;
+	for_each_sched_entity(se) {
+		struct cfs_rq *qcfs_rq = cfs_rq_of(se);
+		/* throttled entity or throttle-on-deactivate */
+		if (!se->on_rq)
+			goto done;
+
+		dequeue_entity(qcfs_rq, se, DEQUEUE_SLEEP);
+
+		if (cfs_rq_is_idle(group_cfs_rq(se)))
+			idle_task_delta = cfs_rq->h_nr_running;
+
+		qcfs_rq->h_nr_running -= task_delta;
+		qcfs_rq->idle_h_nr_running -= idle_task_delta;
+
+		if (qcfs_rq->load.weight) {
+			/* Avoid re-evaluating load for this entity: */
+			se = parent_entity(se);
+			break;
+		}
+	}
+
+	for_each_sched_entity(se) {
+		struct cfs_rq *qcfs_rq = cfs_rq_of(se);
+		/* throttled entity or throttle-on-deactivate */
+		if (!se->on_rq)
+			goto done;
+
+		update_load_avg(qcfs_rq, se, 0);
+		se_update_runnable(se);
+
+		if (cfs_rq_is_idle(group_cfs_rq(se)))
+			idle_task_delta = cfs_rq->h_nr_running;
+
+		qcfs_rq->h_nr_running -= task_delta;
+		qcfs_rq->idle_h_nr_running -= idle_task_delta;
+	}
+
+	/* At this point se is NULL and we are at root level*/
+	sub_nr_running(rq, task_delta);
+
+done:
+	/*
+	 * Note: distribution will already see us throttled via the
+	 * throttled-list.  rq->lock protects completion.
+	 */
+	cfs_rq->throttled = 1;
+	cfs_rq->throttled_clock = rq_clock(rq);
+	return true;
+}
+
+void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	struct rq *rq = rq_of(cfs_rq);
+	struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+	struct sched_entity *se;
+	long task_delta, idle_task_delta;
+
+	se = cfs_rq->tg->se[cpu_of(rq)];
+
+	cfs_rq->throttled = 0;
+
+	update_rq_clock(rq);
+
+	raw_spin_lock(&cfs_b->lock);
+	cfs_b->throttled_time += rq_clock(rq) - cfs_rq->throttled_clock;
+	list_del_rcu(&cfs_rq->throttled_list);
+	raw_spin_unlock(&cfs_b->lock);
+
+	/* update hierarchical throttle state */
+	walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq);
+
+	if (!cfs_rq->load.weight) {
+		if (!cfs_rq->on_list)
+			return;
+		/*
+		 * Nothing to run but something to decay (on_list)?
+		 * Complete the branch.
+		 */
+		for_each_sched_entity(se) {
+			if (list_add_leaf_cfs_rq(cfs_rq_of(se)))
+				break;
+		}
+		goto unthrottle_throttle;
+	}
+
+	task_delta = cfs_rq->h_nr_running;
+	idle_task_delta = cfs_rq->idle_h_nr_running;
+	for_each_sched_entity(se) {
+		struct cfs_rq *qcfs_rq = cfs_rq_of(se);
+
+		if (se->on_rq)
+			break;
+		enqueue_entity(qcfs_rq, se, ENQUEUE_WAKEUP);
+
+		if (cfs_rq_is_idle(group_cfs_rq(se)))
+			idle_task_delta = cfs_rq->h_nr_running;
+
+		qcfs_rq->h_nr_running += task_delta;
+		qcfs_rq->idle_h_nr_running += idle_task_delta;
+
+		/* end evaluation on encountering a throttled cfs_rq */
+		if (cfs_rq_throttled(qcfs_rq))
+			goto unthrottle_throttle;
+	}
+
+	for_each_sched_entity(se) {
+		struct cfs_rq *qcfs_rq = cfs_rq_of(se);
+
+		update_load_avg(qcfs_rq, se, UPDATE_TG);
+		se_update_runnable(se);
+
+		if (cfs_rq_is_idle(group_cfs_rq(se)))
+			idle_task_delta = cfs_rq->h_nr_running;
+
+		qcfs_rq->h_nr_running += task_delta;
+		qcfs_rq->idle_h_nr_running += idle_task_delta;
+
+		/* end evaluation on encountering a throttled cfs_rq */
+		if (cfs_rq_throttled(qcfs_rq))
+			goto unthrottle_throttle;
+	}
+
+	/* At this point se is NULL and we are at root level*/
+	add_nr_running(rq, task_delta);
+
+unthrottle_throttle:
+	assert_list_leaf_cfs_rq(rq);
+
+	/* Determine whether we need to wake up potentially idle CPU: */
+	if (rq->curr == rq->idle && rq->cfs.nr_running)
+		resched_curr(rq);
+}
+
+static void distribute_cfs_runtime(struct cfs_bandwidth *cfs_b)
+{
+	struct cfs_rq *cfs_rq;
+	u64 runtime, remaining = 1;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq,
+				throttled_list) {
+		struct rq *rq = rq_of(cfs_rq);
+		struct rq_flags rf;
+
+		rq_lock_irqsave(rq, &rf);
+		if (!cfs_rq_throttled(cfs_rq))
+			goto next;
+
+		/* By the above check, this should never be true */
+		SCHED_WARN_ON(cfs_rq->runtime_remaining > 0);
+
+		raw_spin_lock(&cfs_b->lock);
+		runtime = -cfs_rq->runtime_remaining + 1;
+		if (runtime > cfs_b->runtime)
+			runtime = cfs_b->runtime;
+		cfs_b->runtime -= runtime;
+		remaining = cfs_b->runtime;
+		raw_spin_unlock(&cfs_b->lock);
+
+		cfs_rq->runtime_remaining += runtime;
+
+		/* we check whether we're throttled above */
+		if (cfs_rq->runtime_remaining > 0)
+			unthrottle_cfs_rq(cfs_rq);
+
+next:
+		rq_unlock_irqrestore(rq, &rf);
+
+		if (!remaining)
+			break;
+	}
+	rcu_read_unlock();
+}
+
+/*
+ * Responsible for refilling a task_group's bandwidth and unthrottling its
+ * cfs_rqs as appropriate. If there has been no activity within the last
+ * period the timer is deactivated until scheduling resumes; cfs_b->idle is
+ * used to track this state.
+ */
+static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun, unsigned long flags)
+{
+	int throttled;
+
+	/* no need to continue the timer with no bandwidth constraint */
+	if (cfs_b->quota == RUNTIME_INF)
+		goto out_deactivate;
+
+	throttled = !list_empty(&cfs_b->throttled_cfs_rq);
+	cfs_b->nr_periods += overrun;
+
+	/* Refill extra burst quota even if cfs_b->idle */
+	__refill_cfs_bandwidth_runtime(cfs_b);
+
+	/*
+	 * idle depends on !throttled (for the case of a large deficit), and if
+	 * we're going inactive then everything else can be deferred
+	 */
+	if (cfs_b->idle && !throttled)
+		goto out_deactivate;
+
+	if (!throttled) {
+		/* mark as potentially idle for the upcoming period */
+		cfs_b->idle = 1;
+		return 0;
+	}
+
+	/* account preceding periods in which throttling occurred */
+	cfs_b->nr_throttled += overrun;
+
+	/*
+	 * This check is repeated as we release cfs_b->lock while we unthrottle.
+	 */
+	while (throttled && cfs_b->runtime > 0) {
+		raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+		/* we can't nest cfs_b->lock while distributing bandwidth */
+		distribute_cfs_runtime(cfs_b);
+		raw_spin_lock_irqsave(&cfs_b->lock, flags);
+
+		throttled = !list_empty(&cfs_b->throttled_cfs_rq);
+	}
+
+	/*
+	 * While we are ensured activity in the period following an
+	 * unthrottle, this also covers the case in which the new bandwidth is
+	 * insufficient to cover the existing bandwidth deficit.  (Forcing the
+	 * timer to remain active while there are any throttled entities.)
+	 */
+	cfs_b->idle = 0;
+
+	return 0;
+
+out_deactivate:
+	return 1;
+}
+
+/* a cfs_rq won't donate quota below this amount */
+static const u64 min_cfs_rq_runtime = 1 * NSEC_PER_MSEC;
+/* minimum remaining period time to redistribute slack quota */
+static const u64 min_bandwidth_expiration = 2 * NSEC_PER_MSEC;
+/* how long we wait to gather additional slack before distributing */
+static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC;
+
+/*
+ * Are we near the end of the current quota period?
+ *
+ * Requires cfs_b->lock for hrtimer_expires_remaining to be safe against the
+ * hrtimer base being cleared by hrtimer_start. In the case of
+ * migrate_hrtimers, base is never cleared, so we are fine.
+ */
+static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire)
+{
+	struct hrtimer *refresh_timer = &cfs_b->period_timer;
+	s64 remaining;
+
+	/* if the call-back is running a quota refresh is already occurring */
+	if (hrtimer_callback_running(refresh_timer))
+		return 1;
+
+	/* is a quota refresh about to occur? */
+	remaining = ktime_to_ns(hrtimer_expires_remaining(refresh_timer));
+	if (remaining < (s64)min_expire)
+		return 1;
+
+	return 0;
+}
+
+static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+	u64 min_left = cfs_bandwidth_slack_period + min_bandwidth_expiration;
+
+	/* if there's a quota refresh soon don't bother with slack */
+	if (runtime_refresh_within(cfs_b, min_left))
+		return;
+
+	/* don't push forwards an existing deferred unthrottle */
+	if (cfs_b->slack_started)
+		return;
+	cfs_b->slack_started = true;
+
+	hrtimer_start(&cfs_b->slack_timer,
+			ns_to_ktime(cfs_bandwidth_slack_period),
+			HRTIMER_MODE_REL);
+}
+
+/* we know any runtime found here is valid as update_curr() precedes return */
+static void __return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+	struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
+	s64 slack_runtime = cfs_rq->runtime_remaining - min_cfs_rq_runtime;
+
+	if (slack_runtime <= 0)
+		return;
+
+	raw_spin_lock(&cfs_b->lock);
+	if (cfs_b->quota != RUNTIME_INF) {
+		cfs_b->runtime += slack_runtime;
+
+		/* we are under rq->lock, defer unthrottling using a timer */
+		if (cfs_b->runtime > sched_cfs_bandwidth_slice() &&
+		    !list_empty(&cfs_b->throttled_cfs_rq))
+			start_cfs_slack_bandwidth(cfs_b);
+	}
+	raw_spin_unlock(&cfs_b->lock);
+
+	/* even if it's not valid for return we don't want to try again */
+	cfs_rq->runtime_remaining -= slack_runtime;
+}
+
+static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+	if (!cfs_bandwidth_used())
+		return;
+
+	if (!cfs_rq->runtime_enabled || cfs_rq->nr_running)
+		return;
+
+	__return_cfs_rq_runtime(cfs_rq);
+}
+
+/*
+ * This is done with a timer (instead of inline with bandwidth return) since
+ * it's necessary to juggle rq->locks to unthrottle their respective cfs_rqs.
+ */
+static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
+{
+	u64 runtime = 0, slice = sched_cfs_bandwidth_slice();
+	unsigned long flags;
+
+	/* confirm we're still not at a refresh boundary */
+	raw_spin_lock_irqsave(&cfs_b->lock, flags);
+	cfs_b->slack_started = false;
+
+	if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) {
+		raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+		return;
+	}
+
+	if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice)
+		runtime = cfs_b->runtime;
+
+	raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+
+	if (!runtime)
+		return;
+
+	distribute_cfs_runtime(cfs_b);
+}
+
+/*
+ * When a group wakes up we want to make sure that its quota is not already
+ * expired/exceeded, otherwise it may be allowed to steal additional ticks of
+ * runtime as update_curr() throttling can not trigger until it's on-rq.
+ */
+static void check_enqueue_throttle(struct cfs_rq *cfs_rq)
+{
+	if (!cfs_bandwidth_used())
+		return;
+
+	/* an active group must be handled by the update_curr()->put() path */
+	if (!cfs_rq->runtime_enabled || cfs_rq->curr)
+		return;
+
+	/* ensure the group is not already throttled */
+	if (cfs_rq_throttled(cfs_rq))
+		return;
+
+	/* update runtime allocation */
+	account_cfs_rq_runtime(cfs_rq, 0);
+	if (cfs_rq->runtime_remaining <= 0)
+		throttle_cfs_rq(cfs_rq);
+}
+
+static void sync_throttle(struct task_group *tg, int cpu)
+{
+	struct cfs_rq *pcfs_rq, *cfs_rq;
+
+	if (!cfs_bandwidth_used())
+		return;
+
+	if (!tg->parent)
+		return;
+
+	cfs_rq = tg->cfs_rq[cpu];
+	pcfs_rq = tg->parent->cfs_rq[cpu];
+
+	cfs_rq->throttle_count = pcfs_rq->throttle_count;
+	cfs_rq->throttled_clock_pelt = rq_clock_pelt(cpu_rq(cpu));
+}
+
+/* conditionally throttle active cfs_rq's from put_prev_entity() */
+static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+	if (!cfs_bandwidth_used())
+		return false;
+
+	if (likely(!cfs_rq->runtime_enabled || cfs_rq->runtime_remaining > 0))
+		return false;
+
+	/*
+	 * it's possible for a throttled entity to be forced into a running
+	 * state (e.g. set_curr_task), in this case we're finished.
+	 */
+	if (cfs_rq_throttled(cfs_rq))
+		return true;
+
+	return throttle_cfs_rq(cfs_rq);
+}
+
+static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer)
+{
+	struct cfs_bandwidth *cfs_b =
+		container_of(timer, struct cfs_bandwidth, slack_timer);
+
+	do_sched_cfs_slack_timer(cfs_b);
+
+	return HRTIMER_NORESTART;
+}
+
+extern const u64 max_cfs_quota_period;
+
+static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
+{
+	struct cfs_bandwidth *cfs_b =
+		container_of(timer, struct cfs_bandwidth, period_timer);
+	unsigned long flags;
+	int overrun;
+	int idle = 0;
+	int count = 0;
+
+	raw_spin_lock_irqsave(&cfs_b->lock, flags);
+	for (;;) {
+		overrun = hrtimer_forward_now(timer, cfs_b->period);
+		if (!overrun)
+			break;
+
+		idle = do_sched_cfs_period_timer(cfs_b, overrun, flags);
+
+		if (++count > 3) {
+			u64 new, old = ktime_to_ns(cfs_b->period);
+
+			/*
+			 * Grow period by a factor of 2 to avoid losing precision.
+			 * Precision loss in the quota/period ratio can cause __cfs_schedulable
+			 * to fail.
+			 */
+			new = old * 2;
+			if (new < max_cfs_quota_period) {
+				cfs_b->period = ns_to_ktime(new);
+				cfs_b->quota *= 2;
+				cfs_b->burst *= 2;
+
+				pr_warn_ratelimited(
+	"cfs_period_timer[cpu%d]: period too short, scaling up (new cfs_period_us = %lld, cfs_quota_us = %lld)\n",
+					smp_processor_id(),
+					div_u64(new, NSEC_PER_USEC),
+					div_u64(cfs_b->quota, NSEC_PER_USEC));
+			} else {
+				pr_warn_ratelimited(
+	"cfs_period_timer[cpu%d]: period too short, but cannot scale up without losing precision (cfs_period_us = %lld, cfs_quota_us = %lld)\n",
+					smp_processor_id(),
+					div_u64(old, NSEC_PER_USEC),
+					div_u64(cfs_b->quota, NSEC_PER_USEC));
+			}
+
+			/* reset count so we don't come right back in here */
+			count = 0;
+		}
+	}
+	if (idle)
+		cfs_b->period_active = 0;
+	raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
+
+	return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
+}
+
+void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+	raw_spin_lock_init(&cfs_b->lock);
+	cfs_b->runtime = 0;
+	cfs_b->quota = RUNTIME_INF;
+	cfs_b->period = ns_to_ktime(default_cfs_period());
+	cfs_b->burst = 0;
+
+	INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq);
+	hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
+	cfs_b->period_timer.function = sched_cfs_period_timer;
+	hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	cfs_b->slack_timer.function = sched_cfs_slack_timer;
+	cfs_b->slack_started = false;
+}
+
+static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)
+{
+	cfs_rq->runtime_enabled = 0;
+	INIT_LIST_HEAD(&cfs_rq->throttled_list);
+}
+
+void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+	lockdep_assert_held(&cfs_b->lock);
+
+	if (cfs_b->period_active)
+		return;
+
+	cfs_b->period_active = 1;
+	hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period);
+	hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED);
+}
+
+static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
+{
+	/* init_cfs_bandwidth() was not called */
+	if (!cfs_b->throttled_cfs_rq.next)
+		return;
+
+	hrtimer_cancel(&cfs_b->period_timer);
+	hrtimer_cancel(&cfs_b->slack_timer);
+}
+
+/*
+ * Both these CPU hotplug callbacks race against unregister_fair_sched_group()
+ *
+ * The race is harmless, since modifying bandwidth settings of unhooked group
+ * bits doesn't do much.
+ */
+
+/* cpu online callback */
+static void __maybe_unused update_runtime_enabled(struct rq *rq)
+{
+	struct task_group *tg;
+
+	lockdep_assert_rq_held(rq);
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(tg, &task_groups, list) {
+		struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
+		struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+		raw_spin_lock(&cfs_b->lock);
+		cfs_rq->runtime_enabled = cfs_b->quota != RUNTIME_INF;
+		raw_spin_unlock(&cfs_b->lock);
+	}
+	rcu_read_unlock();
+}
+
+/* cpu offline callback */
+static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq)
+{
+	struct task_group *tg;
+
+	lockdep_assert_rq_held(rq);
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(tg, &task_groups, list) {
+		struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
+
+		if (!cfs_rq->runtime_enabled)
+			continue;
+
+		/*
+		 * clock_task is not advancing so we just need to make sure
+		 * there's some valid quota amount
+		 */
+		cfs_rq->runtime_remaining = 1;
+		/*
+		 * Offline rq is schedulable till CPU is completely disabled
+		 * in take_cpu_down(), so we prevent new cfs throttling here.
+		 */
+		cfs_rq->runtime_enabled = 0;
+
+		if (cfs_rq_throttled(cfs_rq))
+			unthrottle_cfs_rq(cfs_rq);
+	}
+	rcu_read_unlock();
+}
+
+#else /* CONFIG_CFS_BANDWIDTH */
+
+static inline bool cfs_bandwidth_used(void)
+{
+	return false;
+}
+
+static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) {}
+static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq) { return false; }
+static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {}
+static inline void sync_throttle(struct task_group *tg, int cpu) {}
+static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
+
+static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq)
+{
+	return 0;
+}
+
+static inline int throttled_hierarchy(struct cfs_rq *cfs_rq)
+{
+	return 0;
+}
+
+static inline int throttled_lb_pair(struct task_group *tg,
+				    int src_cpu, int dest_cpu)
+{
+	return 0;
+}
+
+void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
+#endif
+
+static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
+{
+	return NULL;
+}
+static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
+static inline void update_runtime_enabled(struct rq *rq) {}
+static inline void unthrottle_offline_cfs_rqs(struct rq *rq) {}
+
+#endif /* CONFIG_CFS_BANDWIDTH */
+
+/**************************************************
+ * CFS operations on tasks:
+ */
+
+#ifdef CONFIG_SCHED_HRTICK
+static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
+{
+	struct sched_entity *se = &p->se;
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+	SCHED_WARN_ON(task_rq(p) != rq);
+
+	if (rq->cfs.h_nr_running > 1) {
+		u64 slice = sched_slice(cfs_rq, se);
+		u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime;
+		s64 delta = slice - ran;
+
+		if (delta < 0) {
+			if (task_current(rq, p))
+				resched_curr(rq);
+			return;
+		}
+		hrtick_start(rq, delta);
+	}
+}
+
+/*
+ * called from enqueue/dequeue and updates the hrtick when the
+ * current task is from our class and nr_running is low enough
+ * to matter.
+ */
+static void hrtick_update(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+
+	if (!hrtick_enabled_fair(rq) || curr->sched_class != &fair_sched_class)
+		return;
+
+	if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency)
+		hrtick_start_fair(rq, curr);
+}
+#else /* !CONFIG_SCHED_HRTICK */
+static inline void
+hrtick_start_fair(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline void hrtick_update(struct rq *rq)
+{
+}
+#endif
+
+#ifdef CONFIG_SMP
+static inline bool cpu_overutilized(int cpu)
+{
+	unsigned long rq_util_min = uclamp_rq_get(cpu_rq(cpu), UCLAMP_MIN);
+	unsigned long rq_util_max = uclamp_rq_get(cpu_rq(cpu), UCLAMP_MAX);
+
+	/* Return true only if the utilization doesn't fit CPU's capacity */
+	return !util_fits_cpu(cpu_util_cfs(cpu), rq_util_min, rq_util_max, cpu);
+}
+
+static inline void update_overutilized_status(struct rq *rq)
+{
+	if (!READ_ONCE(rq->rd->overutilized) && cpu_overutilized(rq->cpu)) {
+		WRITE_ONCE(rq->rd->overutilized, SG_OVERUTILIZED);
+		trace_sched_overutilized_tp(rq->rd, SG_OVERUTILIZED);
+	}
+}
+#else
+static inline void update_overutilized_status(struct rq *rq) { }
+#endif
+
+/* Runqueue only has SCHED_IDLE tasks enqueued */
+static int sched_idle_rq(struct rq *rq)
+{
+	return unlikely(rq->nr_running == rq->cfs.idle_h_nr_running &&
+			rq->nr_running);
+}
+
+/*
+ * Returns true if cfs_rq only has SCHED_IDLE entities enqueued. Note the use
+ * of idle_nr_running, which does not consider idle descendants of normal
+ * entities.
+ */
+static bool sched_idle_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	return cfs_rq->nr_running &&
+		cfs_rq->nr_running == cfs_rq->idle_nr_running;
+}
+
+#ifdef CONFIG_SMP
+static int sched_idle_cpu(int cpu)
+{
+	return sched_idle_rq(cpu_rq(cpu));
+}
+#endif
+
+/*
+ * The enqueue_task method is called before nr_running is
+ * increased. Here we update the fair scheduling stats and
+ * then put the task into the rbtree:
+ */
+static void
+enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
+{
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se = &p->se;
+	int idle_h_nr_running = task_has_idle_policy(p);
+	int task_new = !(flags & ENQUEUE_WAKEUP);
+
+	/*
+	 * The code below (indirectly) updates schedutil which looks at
+	 * the cfs_rq utilization to select a frequency.
+	 * Let's add the task's estimated utilization to the cfs_rq's
+	 * estimated utilization, before we update schedutil.
+	 */
+	util_est_enqueue(&rq->cfs, p);
+
+	/*
+	 * If in_iowait is set, the code below may not trigger any cpufreq
+	 * utilization updates, so do it here explicitly with the IOWAIT flag
+	 * passed.
+	 */
+	if (p->in_iowait)
+		cpufreq_update_util(rq, SCHED_CPUFREQ_IOWAIT);
+
+	for_each_sched_entity(se) {
+		if (se->on_rq)
+			break;
+		cfs_rq = cfs_rq_of(se);
+		enqueue_entity(cfs_rq, se, flags);
+
+		cfs_rq->h_nr_running++;
+		cfs_rq->idle_h_nr_running += idle_h_nr_running;
+
+		if (cfs_rq_is_idle(cfs_rq))
+			idle_h_nr_running = 1;
+
+		/* end evaluation on encountering a throttled cfs_rq */
+		if (cfs_rq_throttled(cfs_rq))
+			goto enqueue_throttle;
+
+		flags = ENQUEUE_WAKEUP;
+	}
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+
+		update_load_avg(cfs_rq, se, UPDATE_TG);
+		se_update_runnable(se);
+		update_cfs_group(se);
+
+		cfs_rq->h_nr_running++;
+		cfs_rq->idle_h_nr_running += idle_h_nr_running;
+
+		if (cfs_rq_is_idle(cfs_rq))
+			idle_h_nr_running = 1;
+
+		/* end evaluation on encountering a throttled cfs_rq */
+		if (cfs_rq_throttled(cfs_rq))
+			goto enqueue_throttle;
+	}
+
+	/* At this point se is NULL and we are at root level*/
+	add_nr_running(rq, 1);
+
+	/*
+	 * Since new tasks are assigned an initial util_avg equal to
+	 * half of the spare capacity of their CPU, tiny tasks have the
+	 * ability to cross the overutilized threshold, which will
+	 * result in the load balancer ruining all the task placement
+	 * done by EAS. As a way to mitigate that effect, do not account
+	 * for the first enqueue operation of new tasks during the
+	 * overutilized flag detection.
+	 *
+	 * A better way of solving this problem would be to wait for
+	 * the PELT signals of tasks to converge before taking them
+	 * into account, but that is not straightforward to implement,
+	 * and the following generally works well enough in practice.
+	 */
+	if (!task_new)
+		update_overutilized_status(rq);
+
+enqueue_throttle:
+	assert_list_leaf_cfs_rq(rq);
+
+	hrtick_update(rq);
+}
+
+static void set_next_buddy(struct sched_entity *se);
+
+/*
+ * The dequeue_task method is called before nr_running is
+ * decreased. We remove the task from the rbtree and
+ * update the fair scheduling stats:
+ */
+static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
+{
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se = &p->se;
+	int task_sleep = flags & DEQUEUE_SLEEP;
+	int idle_h_nr_running = task_has_idle_policy(p);
+	bool was_sched_idle = sched_idle_rq(rq);
+
+	util_est_dequeue(&rq->cfs, p);
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+		dequeue_entity(cfs_rq, se, flags);
+
+		cfs_rq->h_nr_running--;
+		cfs_rq->idle_h_nr_running -= idle_h_nr_running;
+
+		if (cfs_rq_is_idle(cfs_rq))
+			idle_h_nr_running = 1;
+
+		/* end evaluation on encountering a throttled cfs_rq */
+		if (cfs_rq_throttled(cfs_rq))
+			goto dequeue_throttle;
+
+		/* Don't dequeue parent if it has other entities besides us */
+		if (cfs_rq->load.weight) {
+			/* Avoid re-evaluating load for this entity: */
+			se = parent_entity(se);
+			/*
+			 * Bias pick_next to pick a task from this cfs_rq, as
+			 * p is sleeping when it is within its sched_slice.
+			 */
+			if (task_sleep && se && !throttled_hierarchy(cfs_rq))
+				set_next_buddy(se);
+			break;
+		}
+		flags |= DEQUEUE_SLEEP;
+	}
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+
+		update_load_avg(cfs_rq, se, UPDATE_TG);
+		se_update_runnable(se);
+		update_cfs_group(se);
+
+		cfs_rq->h_nr_running--;
+		cfs_rq->idle_h_nr_running -= idle_h_nr_running;
+
+		if (cfs_rq_is_idle(cfs_rq))
+			idle_h_nr_running = 1;
+
+		/* end evaluation on encountering a throttled cfs_rq */
+		if (cfs_rq_throttled(cfs_rq))
+			goto dequeue_throttle;
+
+	}
+
+	/* At this point se is NULL and we are at root level*/
+	sub_nr_running(rq, 1);
+
+	/* balance early to pull high priority tasks */
+	if (unlikely(!was_sched_idle && sched_idle_rq(rq)))
+		rq->next_balance = jiffies;
+
+dequeue_throttle:
+	util_est_update(&rq->cfs, p, task_sleep);
+	hrtick_update(rq);
+}
+
+#ifdef CONFIG_SMP
+
+/* Working cpumask for: load_balance, load_balance_newidle. */
+static DEFINE_PER_CPU(cpumask_var_t, load_balance_mask);
+static DEFINE_PER_CPU(cpumask_var_t, select_rq_mask);
+
+#ifdef CONFIG_NO_HZ_COMMON
+
+static struct {
+	cpumask_var_t idle_cpus_mask;
+	atomic_t nr_cpus;
+	int has_blocked;		/* Idle CPUS has blocked load */
+	int needs_update;		/* Newly idle CPUs need their next_balance collated */
+	unsigned long next_balance;     /* in jiffy units */
+	unsigned long next_blocked;	/* Next update of blocked load in jiffies */
+} nohz ____cacheline_aligned;
+
+#endif /* CONFIG_NO_HZ_COMMON */
+
+static unsigned long cpu_load(struct rq *rq)
+{
+	return cfs_rq_load_avg(&rq->cfs);
+}
+
+/*
+ * cpu_load_without - compute CPU load without any contributions from *p
+ * @cpu: the CPU which load is requested
+ * @p: the task which load should be discounted
+ *
+ * The load of a CPU is defined by the load of tasks currently enqueued on that
+ * CPU as well as tasks which are currently sleeping after an execution on that
+ * CPU.
+ *
+ * This method returns the load of the specified CPU by discounting the load of
+ * the specified task, whenever the task is currently contributing to the CPU
+ * load.
+ */
+static unsigned long cpu_load_without(struct rq *rq, struct task_struct *p)
+{
+	struct cfs_rq *cfs_rq;
+	unsigned int load;
+
+	/* Task has no contribution or is new */
+	if (cpu_of(rq) != task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time))
+		return cpu_load(rq);
+
+	cfs_rq = &rq->cfs;
+	load = READ_ONCE(cfs_rq->avg.load_avg);
+
+	/* Discount task's util from CPU's util */
+	lsub_positive(&load, task_h_load(p));
+
+	return load;
+}
+
+static unsigned long cpu_runnable(struct rq *rq)
+{
+	return cfs_rq_runnable_avg(&rq->cfs);
+}
+
+static unsigned long cpu_runnable_without(struct rq *rq, struct task_struct *p)
+{
+	struct cfs_rq *cfs_rq;
+	unsigned int runnable;
+
+	/* Task has no contribution or is new */
+	if (cpu_of(rq) != task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time))
+		return cpu_runnable(rq);
+
+	cfs_rq = &rq->cfs;
+	runnable = READ_ONCE(cfs_rq->avg.runnable_avg);
+
+	/* Discount task's runnable from CPU's runnable */
+	lsub_positive(&runnable, p->se.avg.runnable_avg);
+
+	return runnable;
+}
+
+static unsigned long capacity_of(int cpu)
+{
+	return cpu_rq(cpu)->cpu_capacity;
+}
+
+static void record_wakee(struct task_struct *p)
+{
+	/*
+	 * Only decay a single time; tasks that have less then 1 wakeup per
+	 * jiffy will not have built up many flips.
+	 */
+	if (time_after(jiffies, current->wakee_flip_decay_ts + HZ)) {
+		current->wakee_flips >>= 1;
+		current->wakee_flip_decay_ts = jiffies;
+	}
+
+	if (current->last_wakee != p) {
+		current->last_wakee = p;
+		current->wakee_flips++;
+	}
+}
+
+/*
+ * Detect M:N waker/wakee relationships via a switching-frequency heuristic.
+ *
+ * A waker of many should wake a different task than the one last awakened
+ * at a frequency roughly N times higher than one of its wakees.
+ *
+ * In order to determine whether we should let the load spread vs consolidating
+ * to shared cache, we look for a minimum 'flip' frequency of llc_size in one
+ * partner, and a factor of lls_size higher frequency in the other.
+ *
+ * With both conditions met, we can be relatively sure that the relationship is
+ * non-monogamous, with partner count exceeding socket size.
+ *
+ * Waker/wakee being client/server, worker/dispatcher, interrupt source or
+ * whatever is irrelevant, spread criteria is apparent partner count exceeds
+ * socket size.
+ */
+static int wake_wide(struct task_struct *p)
+{
+	unsigned int master = current->wakee_flips;
+	unsigned int slave = p->wakee_flips;
+	int factor = __this_cpu_read(sd_llc_size);
+
+	if (master < slave)
+		swap(master, slave);
+	if (slave < factor || master < slave * factor)
+		return 0;
+	return 1;
+}
+
+/*
+ * The purpose of wake_affine() is to quickly determine on which CPU we can run
+ * soonest. For the purpose of speed we only consider the waking and previous
+ * CPU.
+ *
+ * wake_affine_idle() - only considers 'now', it check if the waking CPU is
+ *			cache-affine and is (or	will be) idle.
+ *
+ * wake_affine_weight() - considers the weight to reflect the average
+ *			  scheduling latency of the CPUs. This seems to work
+ *			  for the overloaded case.
+ */
+static int
+wake_affine_idle(int this_cpu, int prev_cpu, int sync)
+{
+	/*
+	 * If this_cpu is idle, it implies the wakeup is from interrupt
+	 * context. Only allow the move if cache is shared. Otherwise an
+	 * interrupt intensive workload could force all tasks onto one
+	 * node depending on the IO topology or IRQ affinity settings.
+	 *
+	 * If the prev_cpu is idle and cache affine then avoid a migration.
+	 * There is no guarantee that the cache hot data from an interrupt
+	 * is more important than cache hot data on the prev_cpu and from
+	 * a cpufreq perspective, it's better to have higher utilisation
+	 * on one CPU.
+	 */
+	if (available_idle_cpu(this_cpu) && cpus_share_cache(this_cpu, prev_cpu))
+		return available_idle_cpu(prev_cpu) ? prev_cpu : this_cpu;
+
+	if (sync && cpu_rq(this_cpu)->nr_running == 1)
+		return this_cpu;
+
+	if (available_idle_cpu(prev_cpu))
+		return prev_cpu;
+
+	return nr_cpumask_bits;
+}
+
+static int
+wake_affine_weight(struct sched_domain *sd, struct task_struct *p,
+		   int this_cpu, int prev_cpu, int sync)
+{
+	s64 this_eff_load, prev_eff_load;
+	unsigned long task_load;
+
+	this_eff_load = cpu_load(cpu_rq(this_cpu));
+
+	if (sync) {
+		unsigned long current_load = task_h_load(current);
+
+		if (current_load > this_eff_load)
+			return this_cpu;
+
+		this_eff_load -= current_load;
+	}
+
+	task_load = task_h_load(p);
+
+	this_eff_load += task_load;
+	if (sched_feat(WA_BIAS))
+		this_eff_load *= 100;
+	this_eff_load *= capacity_of(prev_cpu);
+
+	prev_eff_load = cpu_load(cpu_rq(prev_cpu));
+	prev_eff_load -= task_load;
+	if (sched_feat(WA_BIAS))
+		prev_eff_load *= 100 + (sd->imbalance_pct - 100) / 2;
+	prev_eff_load *= capacity_of(this_cpu);
+
+	/*
+	 * If sync, adjust the weight of prev_eff_load such that if
+	 * prev_eff == this_eff that select_idle_sibling() will consider
+	 * stacking the wakee on top of the waker if no other CPU is
+	 * idle.
+	 */
+	if (sync)
+		prev_eff_load += 1;
+
+	return this_eff_load < prev_eff_load ? this_cpu : nr_cpumask_bits;
+}
+
+static int wake_affine(struct sched_domain *sd, struct task_struct *p,
+		       int this_cpu, int prev_cpu, int sync)
+{
+	int target = nr_cpumask_bits;
+
+	if (sched_feat(WA_IDLE))
+		target = wake_affine_idle(this_cpu, prev_cpu, sync);
+
+	if (sched_feat(WA_WEIGHT) && target == nr_cpumask_bits)
+		target = wake_affine_weight(sd, p, this_cpu, prev_cpu, sync);
+
+	schedstat_inc(p->stats.nr_wakeups_affine_attempts);
+	if (target != this_cpu)
+		return prev_cpu;
+
+	schedstat_inc(sd->ttwu_move_affine);
+	schedstat_inc(p->stats.nr_wakeups_affine);
+	return target;
+}
+
+static struct sched_group *
+find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu);
+
+/*
+ * find_idlest_group_cpu - find the idlest CPU among the CPUs in the group.
+ */
+static int
+find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
+{
+	unsigned long load, min_load = ULONG_MAX;
+	unsigned int min_exit_latency = UINT_MAX;
+	u64 latest_idle_timestamp = 0;
+	int least_loaded_cpu = this_cpu;
+	int shallowest_idle_cpu = -1;
+	int i;
+
+	/* Check if we have any choice: */
+	if (group->group_weight == 1)
+		return cpumask_first(sched_group_span(group));
+
+	/* Traverse only the allowed CPUs */
+	for_each_cpu_and(i, sched_group_span(group), p->cpus_ptr) {
+		struct rq *rq = cpu_rq(i);
+
+		if (!sched_core_cookie_match(rq, p))
+			continue;
+
+		if (sched_idle_cpu(i))
+			return i;
+
+		if (available_idle_cpu(i)) {
+			struct cpuidle_state *idle = idle_get_state(rq);
+			if (idle && idle->exit_latency < min_exit_latency) {
+				/*
+				 * We give priority to a CPU whose idle state
+				 * has the smallest exit latency irrespective
+				 * of any idle timestamp.
+				 */
+				min_exit_latency = idle->exit_latency;
+				latest_idle_timestamp = rq->idle_stamp;
+				shallowest_idle_cpu = i;
+			} else if ((!idle || idle->exit_latency == min_exit_latency) &&
+				   rq->idle_stamp > latest_idle_timestamp) {
+				/*
+				 * If equal or no active idle state, then
+				 * the most recently idled CPU might have
+				 * a warmer cache.
+				 */
+				latest_idle_timestamp = rq->idle_stamp;
+				shallowest_idle_cpu = i;
+			}
+		} else if (shallowest_idle_cpu == -1) {
+			load = cpu_load(cpu_rq(i));
+			if (load < min_load) {
+				min_load = load;
+				least_loaded_cpu = i;
+			}
+		}
+	}
+
+	return shallowest_idle_cpu != -1 ? shallowest_idle_cpu : least_loaded_cpu;
+}
+
+static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p,
+				  int cpu, int prev_cpu, int sd_flag)
+{
+	int new_cpu = cpu;
+
+	if (!cpumask_intersects(sched_domain_span(sd), p->cpus_ptr))
+		return prev_cpu;
+
+	/*
+	 * We need task's util for cpu_util_without, sync it up to
+	 * prev_cpu's last_update_time.
+	 */
+	if (!(sd_flag & SD_BALANCE_FORK))
+		sync_entity_load_avg(&p->se);
+
+	while (sd) {
+		struct sched_group *group;
+		struct sched_domain *tmp;
+		int weight;
+
+		if (!(sd->flags & sd_flag)) {
+			sd = sd->child;
+			continue;
+		}
+
+		group = find_idlest_group(sd, p, cpu);
+		if (!group) {
+			sd = sd->child;
+			continue;
+		}
+
+		new_cpu = find_idlest_group_cpu(group, p, cpu);
+		if (new_cpu == cpu) {
+			/* Now try balancing at a lower domain level of 'cpu': */
+			sd = sd->child;
+			continue;
+		}
+
+		/* Now try balancing at a lower domain level of 'new_cpu': */
+		cpu = new_cpu;
+		weight = sd->span_weight;
+		sd = NULL;
+		for_each_domain(cpu, tmp) {
+			if (weight <= tmp->span_weight)
+				break;
+			if (tmp->flags & sd_flag)
+				sd = tmp;
+		}
+	}
+
+	return new_cpu;
+}
+
+static inline int __select_idle_cpu(int cpu, struct task_struct *p)
+{
+	if ((available_idle_cpu(cpu) || sched_idle_cpu(cpu)) &&
+	    sched_cpu_cookie_match(cpu_rq(cpu), p))
+		return cpu;
+
+	return -1;
+}
+
+#ifdef CONFIG_SCHED_SMT
+DEFINE_STATIC_KEY_FALSE(sched_smt_present);
+EXPORT_SYMBOL_GPL(sched_smt_present);
+
+static inline void set_idle_cores(int cpu, int val)
+{
+	struct sched_domain_shared *sds;
+
+	sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+	if (sds)
+		WRITE_ONCE(sds->has_idle_cores, val);
+}
+
+static inline bool test_idle_cores(int cpu)
+{
+	struct sched_domain_shared *sds;
+
+	sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+	if (sds)
+		return READ_ONCE(sds->has_idle_cores);
+
+	return false;
+}
+
+/*
+ * Scans the local SMT mask to see if the entire core is idle, and records this
+ * information in sd_llc_shared->has_idle_cores.
+ *
+ * Since SMT siblings share all cache levels, inspecting this limited remote
+ * state should be fairly cheap.
+ */
+void __update_idle_core(struct rq *rq)
+{
+	int core = cpu_of(rq);
+	int cpu;
+
+	rcu_read_lock();
+	if (test_idle_cores(core))
+		goto unlock;
+
+	for_each_cpu(cpu, cpu_smt_mask(core)) {
+		if (cpu == core)
+			continue;
+
+		if (!available_idle_cpu(cpu))
+			goto unlock;
+	}
+
+	set_idle_cores(core, 1);
+unlock:
+	rcu_read_unlock();
+}
+
+/*
+ * Scan the entire LLC domain for idle cores; this dynamically switches off if
+ * there are no idle cores left in the system; tracked through
+ * sd_llc->shared->has_idle_cores and enabled through update_idle_core() above.
+ */
+static int select_idle_core(struct task_struct *p, int core, struct cpumask *cpus, int *idle_cpu)
+{
+	bool idle = true;
+	int cpu;
+
+	for_each_cpu(cpu, cpu_smt_mask(core)) {
+		if (!available_idle_cpu(cpu)) {
+			idle = false;
+			if (*idle_cpu == -1) {
+				if (sched_idle_cpu(cpu) && cpumask_test_cpu(cpu, p->cpus_ptr)) {
+					*idle_cpu = cpu;
+					break;
+				}
+				continue;
+			}
+			break;
+		}
+		if (*idle_cpu == -1 && cpumask_test_cpu(cpu, p->cpus_ptr))
+			*idle_cpu = cpu;
+	}
+
+	if (idle)
+		return core;
+
+	cpumask_andnot(cpus, cpus, cpu_smt_mask(core));
+	return -1;
+}
+
+/*
+ * Scan the local SMT mask for idle CPUs.
+ */
+static int select_idle_smt(struct task_struct *p, int target)
+{
+	int cpu;
+
+	for_each_cpu_and(cpu, cpu_smt_mask(target), p->cpus_ptr) {
+		if (cpu == target)
+			continue;
+		if (available_idle_cpu(cpu) || sched_idle_cpu(cpu))
+			return cpu;
+	}
+
+	return -1;
+}
+
+#else /* CONFIG_SCHED_SMT */
+
+static inline void set_idle_cores(int cpu, int val)
+{
+}
+
+static inline bool test_idle_cores(int cpu)
+{
+	return false;
+}
+
+static inline int select_idle_core(struct task_struct *p, int core, struct cpumask *cpus, int *idle_cpu)
+{
+	return __select_idle_cpu(core, p);
+}
+
+static inline int select_idle_smt(struct task_struct *p, int target)
+{
+	return -1;
+}
+
+#endif /* CONFIG_SCHED_SMT */
+
+/*
+ * Scan the LLC domain for idle CPUs; this is dynamically regulated by
+ * comparing the average scan cost (tracked in sd->avg_scan_cost) against the
+ * average idle time for this rq (as found in rq->avg_idle).
+ */
+static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool has_idle_core, int target)
+{
+	struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_rq_mask);
+	int i, cpu, idle_cpu = -1, nr = INT_MAX;
+	struct sched_domain_shared *sd_share;
+	struct rq *this_rq = this_rq();
+	int this = smp_processor_id();
+	struct sched_domain *this_sd = NULL;
+	u64 time = 0;
+
+	cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);
+
+	if (sched_feat(SIS_PROP) && !has_idle_core) {
+		u64 avg_cost, avg_idle, span_avg;
+		unsigned long now = jiffies;
+
+		this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc));
+		if (!this_sd)
+			return -1;
+
+		/*
+		 * If we're busy, the assumption that the last idle period
+		 * predicts the future is flawed; age away the remaining
+		 * predicted idle time.
+		 */
+		if (unlikely(this_rq->wake_stamp < now)) {
+			while (this_rq->wake_stamp < now && this_rq->wake_avg_idle) {
+				this_rq->wake_stamp++;
+				this_rq->wake_avg_idle >>= 1;
+			}
+		}
+
+		avg_idle = this_rq->wake_avg_idle;
+		avg_cost = this_sd->avg_scan_cost + 1;
+
+		span_avg = sd->span_weight * avg_idle;
+		if (span_avg > 4*avg_cost)
+			nr = div_u64(span_avg, avg_cost);
+		else
+			nr = 4;
+
+		time = cpu_clock(this);
+	}
+
+	if (sched_feat(SIS_UTIL)) {
+		sd_share = rcu_dereference(per_cpu(sd_llc_shared, target));
+		if (sd_share) {
+			/* because !--nr is the condition to stop scan */
+			nr = READ_ONCE(sd_share->nr_idle_scan) + 1;
+			/* overloaded LLC is unlikely to have idle cpu/core */
+			if (nr == 1)
+				return -1;
+		}
+	}
+
+	for_each_cpu_wrap(cpu, cpus, target + 1) {
+		if (has_idle_core) {
+			i = select_idle_core(p, cpu, cpus, &idle_cpu);
+			if ((unsigned int)i < nr_cpumask_bits)
+				return i;
+
+		} else {
+			if (!--nr)
+				return -1;
+			idle_cpu = __select_idle_cpu(cpu, p);
+			if ((unsigned int)idle_cpu < nr_cpumask_bits)
+				break;
+		}
+	}
+
+	if (has_idle_core)
+		set_idle_cores(target, false);
+
+	if (sched_feat(SIS_PROP) && this_sd && !has_idle_core) {
+		time = cpu_clock(this) - time;
+
+		/*
+		 * Account for the scan cost of wakeups against the average
+		 * idle time.
+		 */
+		this_rq->wake_avg_idle -= min(this_rq->wake_avg_idle, time);
+
+		update_avg(&this_sd->avg_scan_cost, time);
+	}
+
+	return idle_cpu;
+}
+
+/*
+ * Scan the asym_capacity domain for idle CPUs; pick the first idle one on which
+ * the task fits. If no CPU is big enough, but there are idle ones, try to
+ * maximize capacity.
+ */
+static int
+select_idle_capacity(struct task_struct *p, struct sched_domain *sd, int target)
+{
+	unsigned long task_util, util_min, util_max, best_cap = 0;
+	int fits, best_fits = 0;
+	int cpu, best_cpu = -1;
+	struct cpumask *cpus;
+
+	cpus = this_cpu_cpumask_var_ptr(select_rq_mask);
+	cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);
+
+	task_util = task_util_est(p);
+	util_min = uclamp_eff_value(p, UCLAMP_MIN);
+	util_max = uclamp_eff_value(p, UCLAMP_MAX);
+
+	for_each_cpu_wrap(cpu, cpus, target) {
+		unsigned long cpu_cap = capacity_of(cpu);
+
+		if (!available_idle_cpu(cpu) && !sched_idle_cpu(cpu))
+			continue;
+
+		fits = util_fits_cpu(task_util, util_min, util_max, cpu);
+
+		/* This CPU fits with all requirements */
+		if (fits > 0)
+			return cpu;
+		/*
+		 * Only the min performance hint (i.e. uclamp_min) doesn't fit.
+		 * Look for the CPU with best capacity.
+		 */
+		else if (fits < 0)
+			cpu_cap = capacity_orig_of(cpu) - thermal_load_avg(cpu_rq(cpu));
+
+		/*
+		 * First, select CPU which fits better (-1 being better than 0).
+		 * Then, select the one with best capacity at same level.
+		 */
+		if ((fits < best_fits) ||
+		    ((fits == best_fits) && (cpu_cap > best_cap))) {
+			best_cap = cpu_cap;
+			best_cpu = cpu;
+			best_fits = fits;
+		}
+	}
+
+	return best_cpu;
+}
+
+static inline bool asym_fits_cpu(unsigned long util,
+				 unsigned long util_min,
+				 unsigned long util_max,
+				 int cpu)
+{
+	if (sched_asym_cpucap_active())
+		/*
+		 * Return true only if the cpu fully fits the task requirements
+		 * which include the utilization and the performance hints.
+		 */
+		return (util_fits_cpu(util, util_min, util_max, cpu) > 0);
+
+	return true;
+}
+
+/*
+ * Try and locate an idle core/thread in the LLC cache domain.
+ */
+static int select_idle_sibling(struct task_struct *p, int prev, int target)
+{
+	bool has_idle_core = false;
+	struct sched_domain *sd;
+	unsigned long task_util, util_min, util_max;
+	int i, recent_used_cpu;
+
+	/*
+	 * On asymmetric system, update task utilization because we will check
+	 * that the task fits with cpu's capacity.
+	 */
+	if (sched_asym_cpucap_active()) {
+		sync_entity_load_avg(&p->se);
+		task_util = task_util_est(p);
+		util_min = uclamp_eff_value(p, UCLAMP_MIN);
+		util_max = uclamp_eff_value(p, UCLAMP_MAX);
+	}
+
+	/*
+	 * per-cpu select_rq_mask usage
+	 */
+	lockdep_assert_irqs_disabled();
+
+	if ((available_idle_cpu(target) || sched_idle_cpu(target)) &&
+	    asym_fits_cpu(task_util, util_min, util_max, target))
+		return target;
+
+	/*
+	 * If the previous CPU is cache affine and idle, don't be stupid:
+	 */
+	if (prev != target && cpus_share_cache(prev, target) &&
+	    (available_idle_cpu(prev) || sched_idle_cpu(prev)) &&
+	    asym_fits_cpu(task_util, util_min, util_max, prev))
+		return prev;
+
+	/*
+	 * Allow a per-cpu kthread to stack with the wakee if the
+	 * kworker thread and the tasks previous CPUs are the same.
+	 * The assumption is that the wakee queued work for the
+	 * per-cpu kthread that is now complete and the wakeup is
+	 * essentially a sync wakeup. An obvious example of this
+	 * pattern is IO completions.
+	 */
+	if (is_per_cpu_kthread(current) &&
+	    in_task() &&
+	    prev == smp_processor_id() &&
+	    this_rq()->nr_running <= 1 &&
+	    asym_fits_cpu(task_util, util_min, util_max, prev)) {
+		return prev;
+	}
+
+	/* Check a recently used CPU as a potential idle candidate: */
+	recent_used_cpu = p->recent_used_cpu;
+	p->recent_used_cpu = prev;
+	if (recent_used_cpu != prev &&
+	    recent_used_cpu != target &&
+	    cpus_share_cache(recent_used_cpu, target) &&
+	    (available_idle_cpu(recent_used_cpu) || sched_idle_cpu(recent_used_cpu)) &&
+	    cpumask_test_cpu(recent_used_cpu, p->cpus_ptr) &&
+	    asym_fits_cpu(task_util, util_min, util_max, recent_used_cpu)) {
+		return recent_used_cpu;
+	}
+
+	/*
+	 * For asymmetric CPU capacity systems, our domain of interest is
+	 * sd_asym_cpucapacity rather than sd_llc.
+	 */
+	if (sched_asym_cpucap_active()) {
+		sd = rcu_dereference(per_cpu(sd_asym_cpucapacity, target));
+		/*
+		 * On an asymmetric CPU capacity system where an exclusive
+		 * cpuset defines a symmetric island (i.e. one unique
+		 * capacity_orig value through the cpuset), the key will be set
+		 * but the CPUs within that cpuset will not have a domain with
+		 * SD_ASYM_CPUCAPACITY. These should follow the usual symmetric
+		 * capacity path.
+		 */
+		if (sd) {
+			i = select_idle_capacity(p, sd, target);
+			return ((unsigned)i < nr_cpumask_bits) ? i : target;
+		}
+	}
+
+	sd = rcu_dereference(per_cpu(sd_llc, target));
+	if (!sd)
+		return target;
+
+	if (sched_smt_active()) {
+		has_idle_core = test_idle_cores(target);
+
+		if (!has_idle_core && cpus_share_cache(prev, target)) {
+			i = select_idle_smt(p, prev);
+			if ((unsigned int)i < nr_cpumask_bits)
+				return i;
+		}
+	}
+
+	i = select_idle_cpu(p, sd, has_idle_core, target);
+	if ((unsigned)i < nr_cpumask_bits)
+		return i;
+
+	return target;
+}
+
+/*
+ * Predicts what cpu_util(@cpu) would return if @p was removed from @cpu
+ * (@dst_cpu = -1) or migrated to @dst_cpu.
+ */
+static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst_cpu)
+{
+	struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs;
+	unsigned long util = READ_ONCE(cfs_rq->avg.util_avg);
+
+	/*
+	 * If @dst_cpu is -1 or @p migrates from @cpu to @dst_cpu remove its
+	 * contribution. If @p migrates from another CPU to @cpu add its
+	 * contribution. In all the other cases @cpu is not impacted by the
+	 * migration so its util_avg is already correct.
+	 */
+	if (task_cpu(p) == cpu && dst_cpu != cpu)
+		lsub_positive(&util, task_util(p));
+	else if (task_cpu(p) != cpu && dst_cpu == cpu)
+		util += task_util(p);
+
+	if (sched_feat(UTIL_EST)) {
+		unsigned long util_est;
+
+		util_est = READ_ONCE(cfs_rq->avg.util_est.enqueued);
+
+		/*
+		 * During wake-up @p isn't enqueued yet and doesn't contribute
+		 * to any cpu_rq(cpu)->cfs.avg.util_est.enqueued.
+		 * If @dst_cpu == @cpu add it to "simulate" cpu_util after @p
+		 * has been enqueued.
+		 *
+		 * During exec (@dst_cpu = -1) @p is enqueued and does
+		 * contribute to cpu_rq(cpu)->cfs.util_est.enqueued.
+		 * Remove it to "simulate" cpu_util without @p's contribution.
+		 *
+		 * Despite the task_on_rq_queued(@p) check there is still a
+		 * small window for a possible race when an exec
+		 * select_task_rq_fair() races with LB's detach_task().
+		 *
+		 *   detach_task()
+		 *     deactivate_task()
+		 *       p->on_rq = TASK_ON_RQ_MIGRATING;
+		 *       -------------------------------- A
+		 *       dequeue_task()                    \
+		 *         dequeue_task_fair()              + Race Time
+		 *           util_est_dequeue()            /
+		 *       -------------------------------- B
+		 *
+		 * The additional check "current == p" is required to further
+		 * reduce the race window.
+		 */
+		if (dst_cpu == cpu)
+			util_est += _task_util_est(p);
+		else if (unlikely(task_on_rq_queued(p) || current == p))
+			lsub_positive(&util_est, _task_util_est(p));
+
+		util = max(util, util_est);
+	}
+
+	return min(util, capacity_orig_of(cpu));
+}
+
+/*
+ * cpu_util_without: compute cpu utilization without any contributions from *p
+ * @cpu: the CPU which utilization is requested
+ * @p: the task which utilization should be discounted
+ *
+ * The utilization of a CPU is defined by the utilization of tasks currently
+ * enqueued on that CPU as well as tasks which are currently sleeping after an
+ * execution on that CPU.
+ *
+ * This method returns the utilization of the specified CPU by discounting the
+ * utilization of the specified task, whenever the task is currently
+ * contributing to the CPU utilization.
+ */
+static unsigned long cpu_util_without(int cpu, struct task_struct *p)
+{
+	/* Task has no contribution or is new */
+	if (cpu != task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time))
+		return cpu_util_cfs(cpu);
+
+	return cpu_util_next(cpu, p, -1);
+}
+
+/*
+ * energy_env - Utilization landscape for energy estimation.
+ * @task_busy_time: Utilization contribution by the task for which we test the
+ *                  placement. Given by eenv_task_busy_time().
+ * @pd_busy_time:   Utilization of the whole perf domain without the task
+ *                  contribution. Given by eenv_pd_busy_time().
+ * @cpu_cap:        Maximum CPU capacity for the perf domain.
+ * @pd_cap:         Entire perf domain capacity. (pd->nr_cpus * cpu_cap).
+ */
+struct energy_env {
+	unsigned long task_busy_time;
+	unsigned long pd_busy_time;
+	unsigned long cpu_cap;
+	unsigned long pd_cap;
+};
+
+/*
+ * Compute the task busy time for compute_energy(). This time cannot be
+ * injected directly into effective_cpu_util() because of the IRQ scaling.
+ * The latter only makes sense with the most recent CPUs where the task has
+ * run.
+ */
+static inline void eenv_task_busy_time(struct energy_env *eenv,
+				       struct task_struct *p, int prev_cpu)
+{
+	unsigned long busy_time, max_cap = arch_scale_cpu_capacity(prev_cpu);
+	unsigned long irq = cpu_util_irq(cpu_rq(prev_cpu));
+
+	if (unlikely(irq >= max_cap))
+		busy_time = max_cap;
+	else
+		busy_time = scale_irq_capacity(task_util_est(p), irq, max_cap);
+
+	eenv->task_busy_time = busy_time;
+}
+
+/*
+ * Compute the perf_domain (PD) busy time for compute_energy(). Based on the
+ * utilization for each @pd_cpus, it however doesn't take into account
+ * clamping since the ratio (utilization / cpu_capacity) is already enough to
+ * scale the EM reported power consumption at the (eventually clamped)
+ * cpu_capacity.
+ *
+ * The contribution of the task @p for which we want to estimate the
+ * energy cost is removed (by cpu_util_next()) and must be calculated
+ * separately (see eenv_task_busy_time). This ensures:
+ *
+ *   - A stable PD utilization, no matter which CPU of that PD we want to place
+ *     the task on.
+ *
+ *   - A fair comparison between CPUs as the task contribution (task_util())
+ *     will always be the same no matter which CPU utilization we rely on
+ *     (util_avg or util_est).
+ *
+ * Set @eenv busy time for the PD that spans @pd_cpus. This busy time can't
+ * exceed @eenv->pd_cap.
+ */
+static inline void eenv_pd_busy_time(struct energy_env *eenv,
+				     struct cpumask *pd_cpus,
+				     struct task_struct *p)
+{
+	unsigned long busy_time = 0;
+	int cpu;
+
+	for_each_cpu(cpu, pd_cpus) {
+		unsigned long util = cpu_util_next(cpu, p, -1);
+
+		busy_time += effective_cpu_util(cpu, util, ENERGY_UTIL, NULL);
+	}
+
+	eenv->pd_busy_time = min(eenv->pd_cap, busy_time);
+}
+
+/*
+ * Compute the maximum utilization for compute_energy() when the task @p
+ * is placed on the cpu @dst_cpu.
+ *
+ * Returns the maximum utilization among @eenv->cpus. This utilization can't
+ * exceed @eenv->cpu_cap.
+ */
+static inline unsigned long
+eenv_pd_max_util(struct energy_env *eenv, struct cpumask *pd_cpus,
+		 struct task_struct *p, int dst_cpu)
+{
+	unsigned long max_util = 0;
+	int cpu;
+
+	for_each_cpu(cpu, pd_cpus) {
+		struct task_struct *tsk = (cpu == dst_cpu) ? p : NULL;
+		unsigned long util = cpu_util_next(cpu, p, dst_cpu);
+		unsigned long cpu_util;
+
+		/*
+		 * Performance domain frequency: utilization clamping
+		 * must be considered since it affects the selection
+		 * of the performance domain frequency.
+		 * NOTE: in case RT tasks are running, by default the
+		 * FREQUENCY_UTIL's utilization can be max OPP.
+		 */
+		cpu_util = effective_cpu_util(cpu, util, FREQUENCY_UTIL, tsk);
+		max_util = max(max_util, cpu_util);
+	}
+
+	return min(max_util, eenv->cpu_cap);
+}
+
+/*
+ * compute_energy(): Use the Energy Model to estimate the energy that @pd would
+ * consume for a given utilization landscape @eenv. When @dst_cpu < 0, the task
+ * contribution is ignored.
+ */
+static inline unsigned long
+compute_energy(struct energy_env *eenv, struct perf_domain *pd,
+	       struct cpumask *pd_cpus, struct task_struct *p, int dst_cpu)
+{
+	unsigned long max_util = eenv_pd_max_util(eenv, pd_cpus, p, dst_cpu);
+	unsigned long busy_time = eenv->pd_busy_time;
+
+	if (dst_cpu >= 0)
+		busy_time = min(eenv->pd_cap, busy_time + eenv->task_busy_time);
+
+	return em_cpu_energy(pd->em_pd, max_util, busy_time, eenv->cpu_cap);
+}
+
+/*
+ * find_energy_efficient_cpu(): Find most energy-efficient target CPU for the
+ * waking task. find_energy_efficient_cpu() looks for the CPU with maximum
+ * spare capacity in each performance domain and uses it as a potential
+ * candidate to execute the task. Then, it uses the Energy Model to figure
+ * out which of the CPU candidates is the most energy-efficient.
+ *
+ * The rationale for this heuristic is as follows. In a performance domain,
+ * all the most energy efficient CPU candidates (according to the Energy
+ * Model) are those for which we'll request a low frequency. When there are
+ * several CPUs for which the frequency request will be the same, we don't
+ * have enough data to break the tie between them, because the Energy Model
+ * only includes active power costs. With this model, if we assume that
+ * frequency requests follow utilization (e.g. using schedutil), the CPU with
+ * the maximum spare capacity in a performance domain is guaranteed to be among
+ * the best candidates of the performance domain.
+ *
+ * In practice, it could be preferable from an energy standpoint to pack
+ * small tasks on a CPU in order to let other CPUs go in deeper idle states,
+ * but that could also hurt our chances to go cluster idle, and we have no
+ * ways to tell with the current Energy Model if this is actually a good
+ * idea or not. So, find_energy_efficient_cpu() basically favors
+ * cluster-packing, and spreading inside a cluster. That should at least be
+ * a good thing for latency, and this is consistent with the idea that most
+ * of the energy savings of EAS come from the asymmetry of the system, and
+ * not so much from breaking the tie between identical CPUs. That's also the
+ * reason why EAS is enabled in the topology code only for systems where
+ * SD_ASYM_CPUCAPACITY is set.
+ *
+ * NOTE: Forkees are not accepted in the energy-aware wake-up path because
+ * they don't have any useful utilization data yet and it's not possible to
+ * forecast their impact on energy consumption. Consequently, they will be
+ * placed by find_idlest_cpu() on the least loaded CPU, which might turn out
+ * to be energy-inefficient in some use-cases. The alternative would be to
+ * bias new tasks towards specific types of CPUs first, or to try to infer
+ * their util_avg from the parent task, but those heuristics could hurt
+ * other use-cases too. So, until someone finds a better way to solve this,
+ * let's keep things simple by re-using the existing slow path.
+ */
+static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
+{
+	struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_rq_mask);
+	unsigned long prev_delta = ULONG_MAX, best_delta = ULONG_MAX;
+	unsigned long p_util_min = uclamp_is_used() ? uclamp_eff_value(p, UCLAMP_MIN) : 0;
+	unsigned long p_util_max = uclamp_is_used() ? uclamp_eff_value(p, UCLAMP_MAX) : 1024;
+	struct root_domain *rd = this_rq()->rd;
+	int cpu, best_energy_cpu, target = -1;
+	int prev_fits = -1, best_fits = -1;
+	unsigned long best_thermal_cap = 0;
+	unsigned long prev_thermal_cap = 0;
+	struct sched_domain *sd;
+	struct perf_domain *pd;
+	struct energy_env eenv;
+
+	rcu_read_lock();
+	pd = rcu_dereference(rd->pd);
+	if (!pd || READ_ONCE(rd->overutilized))
+		goto unlock;
+
+	/*
+	 * Energy-aware wake-up happens on the lowest sched_domain starting
+	 * from sd_asym_cpucapacity spanning over this_cpu and prev_cpu.
+	 */
+	sd = rcu_dereference(*this_cpu_ptr(&sd_asym_cpucapacity));
+	while (sd && !cpumask_test_cpu(prev_cpu, sched_domain_span(sd)))
+		sd = sd->parent;
+	if (!sd)
+		goto unlock;
+
+	target = prev_cpu;
+
+	sync_entity_load_avg(&p->se);
+	if (!task_util_est(p) && p_util_min == 0)
+		goto unlock;
+
+	eenv_task_busy_time(&eenv, p, prev_cpu);
+
+	for (; pd; pd = pd->next) {
+		unsigned long util_min = p_util_min, util_max = p_util_max;
+		unsigned long cpu_cap, cpu_thermal_cap, util;
+		long prev_spare_cap = -1, max_spare_cap = -1;
+		unsigned long rq_util_min, rq_util_max;
+		unsigned long cur_delta, base_energy;
+		int max_spare_cap_cpu = -1;
+		int fits, max_fits = -1;
+
+		cpumask_and(cpus, perf_domain_span(pd), cpu_online_mask);
+
+		if (cpumask_empty(cpus))
+			continue;
+
+		/* Account thermal pressure for the energy estimation */
+		cpu = cpumask_first(cpus);
+		cpu_thermal_cap = arch_scale_cpu_capacity(cpu);
+		cpu_thermal_cap -= arch_scale_thermal_pressure(cpu);
+
+		eenv.cpu_cap = cpu_thermal_cap;
+		eenv.pd_cap = 0;
+
+		for_each_cpu(cpu, cpus) {
+			struct rq *rq = cpu_rq(cpu);
+
+			eenv.pd_cap += cpu_thermal_cap;
+
+			if (!cpumask_test_cpu(cpu, sched_domain_span(sd)))
+				continue;
+
+			if (!cpumask_test_cpu(cpu, p->cpus_ptr))
+				continue;
+
+			util = cpu_util_next(cpu, p, cpu);
+			cpu_cap = capacity_of(cpu);
+
+			/*
+			 * Skip CPUs that cannot satisfy the capacity request.
+			 * IOW, placing the task there would make the CPU
+			 * overutilized. Take uclamp into account to see how
+			 * much capacity we can get out of the CPU; this is
+			 * aligned with sched_cpu_util().
+			 */
+			if (uclamp_is_used() && !uclamp_rq_is_idle(rq)) {
+				/*
+				 * Open code uclamp_rq_util_with() except for
+				 * the clamp() part. Ie: apply max aggregation
+				 * only. util_fits_cpu() logic requires to
+				 * operate on non clamped util but must use the
+				 * max-aggregated uclamp_{min, max}.
+				 */
+				rq_util_min = uclamp_rq_get(rq, UCLAMP_MIN);
+				rq_util_max = uclamp_rq_get(rq, UCLAMP_MAX);
+
+				util_min = max(rq_util_min, p_util_min);
+				util_max = max(rq_util_max, p_util_max);
+			}
+
+			fits = util_fits_cpu(util, util_min, util_max, cpu);
+			if (!fits)
+				continue;
+
+			lsub_positive(&cpu_cap, util);
+
+			if (cpu == prev_cpu) {
+				/* Always use prev_cpu as a candidate. */
+				prev_spare_cap = cpu_cap;
+				prev_fits = fits;
+			} else if ((fits > max_fits) ||
+				   ((fits == max_fits) && ((long)cpu_cap > max_spare_cap))) {
+				/*
+				 * Find the CPU with the maximum spare capacity
+				 * among the remaining CPUs in the performance
+				 * domain.
+				 */
+				max_spare_cap = cpu_cap;
+				max_spare_cap_cpu = cpu;
+				max_fits = fits;
+			}
+		}
+
+		if (max_spare_cap_cpu < 0 && prev_spare_cap < 0)
+			continue;
+
+		eenv_pd_busy_time(&eenv, cpus, p);
+		/* Compute the 'base' energy of the pd, without @p */
+		base_energy = compute_energy(&eenv, pd, cpus, p, -1);
+
+		/* Evaluate the energy impact of using prev_cpu. */
+		if (prev_spare_cap > -1) {
+			prev_delta = compute_energy(&eenv, pd, cpus, p,
+						    prev_cpu);
+			/* CPU utilization has changed */
+			if (prev_delta < base_energy)
+				goto unlock;
+			prev_delta -= base_energy;
+			prev_thermal_cap = cpu_thermal_cap;
+			best_delta = min(best_delta, prev_delta);
+		}
+
+		/* Evaluate the energy impact of using max_spare_cap_cpu. */
+		if (max_spare_cap_cpu >= 0 && max_spare_cap > prev_spare_cap) {
+			/* Current best energy cpu fits better */
+			if (max_fits < best_fits)
+				continue;
+
+			/*
+			 * Both don't fit performance hint (i.e. uclamp_min)
+			 * but best energy cpu has better capacity.
+			 */
+			if ((max_fits < 0) &&
+			    (cpu_thermal_cap <= best_thermal_cap))
+				continue;
+
+			cur_delta = compute_energy(&eenv, pd, cpus, p,
+						   max_spare_cap_cpu);
+			/* CPU utilization has changed */
+			if (cur_delta < base_energy)
+				goto unlock;
+			cur_delta -= base_energy;
+
+			/*
+			 * Both fit for the task but best energy cpu has lower
+			 * energy impact.
+			 */
+			if ((max_fits > 0) && (best_fits > 0) &&
+			    (cur_delta >= best_delta))
+				continue;
+
+			best_delta = cur_delta;
+			best_energy_cpu = max_spare_cap_cpu;
+			best_fits = max_fits;
+			best_thermal_cap = cpu_thermal_cap;
+		}
+	}
+	rcu_read_unlock();
+
+	if ((best_fits > prev_fits) ||
+	    ((best_fits > 0) && (best_delta < prev_delta)) ||
+	    ((best_fits < 0) && (best_thermal_cap > prev_thermal_cap)))
+		target = best_energy_cpu;
+
+	return target;
+
+unlock:
+	rcu_read_unlock();
+
+	return target;
+}
+
+/*
+ * select_task_rq_fair: Select target runqueue for the waking task in domains
+ * that have the relevant SD flag set. In practice, this is SD_BALANCE_WAKE,
+ * SD_BALANCE_FORK, or SD_BALANCE_EXEC.
+ *
+ * Balances load by selecting the idlest CPU in the idlest group, or under
+ * certain conditions an idle sibling CPU if the domain has SD_WAKE_AFFINE set.
+ *
+ * Returns the target CPU number.
+ */
+static int
+select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
+{
+	int sync = (wake_flags & WF_SYNC) && !(current->flags & PF_EXITING);
+	struct sched_domain *tmp, *sd = NULL;
+	int cpu = smp_processor_id();
+	int new_cpu = prev_cpu;
+	int want_affine = 0;
+	/* SD_flags and WF_flags share the first nibble */
+	int sd_flag = wake_flags & 0xF;
+
+	/*
+	 * required for stable ->cpus_allowed
+	 */
+	lockdep_assert_held(&p->pi_lock);
+	if (wake_flags & WF_TTWU) {
+		record_wakee(p);
+
+		if (sched_energy_enabled()) {
+			new_cpu = find_energy_efficient_cpu(p, prev_cpu);
+			if (new_cpu >= 0)
+				return new_cpu;
+			new_cpu = prev_cpu;
+		}
+
+		want_affine = !wake_wide(p) && cpumask_test_cpu(cpu, p->cpus_ptr);
+	}
+
+	rcu_read_lock();
+	for_each_domain(cpu, tmp) {
+		/*
+		 * If both 'cpu' and 'prev_cpu' are part of this domain,
+		 * cpu is a valid SD_WAKE_AFFINE target.
+		 */
+		if (want_affine && (tmp->flags & SD_WAKE_AFFINE) &&
+		    cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) {
+			if (cpu != prev_cpu)
+				new_cpu = wake_affine(tmp, p, cpu, prev_cpu, sync);
+
+			sd = NULL; /* Prefer wake_affine over balance flags */
+			break;
+		}
+
+		/*
+		 * Usually only true for WF_EXEC and WF_FORK, as sched_domains
+		 * usually do not have SD_BALANCE_WAKE set. That means wakeup
+		 * will usually go to the fast path.
+		 */
+		if (tmp->flags & sd_flag)
+			sd = tmp;
+		else if (!want_affine)
+			break;
+	}
+
+	if (unlikely(sd)) {
+		/* Slow path */
+		new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag);
+	} else if (wake_flags & WF_TTWU) { /* XXX always ? */
+		/* Fast path */
+		new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
+	}
+	rcu_read_unlock();
+
+	return new_cpu;
+}
+
+/*
+ * Called immediately before a task is migrated to a new CPU; task_cpu(p) and
+ * cfs_rq_of(p) references at time of call are still valid and identify the
+ * previous CPU. The caller guarantees p->pi_lock or task_rq(p)->lock is held.
+ */
+static void migrate_task_rq_fair(struct task_struct *p, int new_cpu)
+{
+	struct sched_entity *se = &p->se;
+
+	/*
+	 * As blocked tasks retain absolute vruntime the migration needs to
+	 * deal with this by subtracting the old and adding the new
+	 * min_vruntime -- the latter is done by enqueue_entity() when placing
+	 * the task on the new runqueue.
+	 */
+	if (READ_ONCE(p->__state) == TASK_WAKING) {
+		struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+		se->vruntime -= u64_u32_load(cfs_rq->min_vruntime);
+	}
+
+	if (!task_on_rq_migrating(p)) {
+		remove_entity_load_avg(se);
+
+		/*
+		 * Here, the task's PELT values have been updated according to
+		 * the current rq's clock. But if that clock hasn't been
+		 * updated in a while, a substantial idle time will be missed,
+		 * leading to an inflation after wake-up on the new rq.
+		 *
+		 * Estimate the missing time from the cfs_rq last_update_time
+		 * and update sched_avg to improve the PELT continuity after
+		 * migration.
+		 */
+		migrate_se_pelt_lag(se);
+	}
+
+	/* Tell new CPU we are migrated */
+	se->avg.last_update_time = 0;
+
+	update_scan_period(p, new_cpu);
+}
+
+static void task_dead_fair(struct task_struct *p)
+{
+	remove_entity_load_avg(&p->se);
+}
+
+static int
+balance_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	if (rq->nr_running)
+		return 1;
+
+	return newidle_balance(rq, rf) != 0;
+}
+#endif /* CONFIG_SMP */
+
+static unsigned long wakeup_gran(struct sched_entity *se)
+{
+	unsigned long gran = sysctl_sched_wakeup_granularity;
+
+	/*
+	 * Since its curr running now, convert the gran from real-time
+	 * to virtual-time in his units.
+	 *
+	 * By using 'se' instead of 'curr' we penalize light tasks, so
+	 * they get preempted easier. That is, if 'se' < 'curr' then
+	 * the resulting gran will be larger, therefore penalizing the
+	 * lighter, if otoh 'se' > 'curr' then the resulting gran will
+	 * be smaller, again penalizing the lighter task.
+	 *
+	 * This is especially important for buddies when the leftmost
+	 * task is higher priority than the buddy.
+	 */
+	return calc_delta_fair(gran, se);
+}
+
+/*
+ * Should 'se' preempt 'curr'.
+ *
+ *             |s1
+ *        |s2
+ *   |s3
+ *         g
+ *      |<--->|c
+ *
+ *  w(c, s1) = -1
+ *  w(c, s2) =  0
+ *  w(c, s3) =  1
+ *
+ */
+static int
+wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
+{
+	s64 gran, vdiff = curr->vruntime - se->vruntime;
+
+	if (vdiff <= 0)
+		return -1;
+
+	gran = wakeup_gran(se);
+	if (vdiff > gran)
+		return 1;
+
+	return 0;
+}
+
+static void set_last_buddy(struct sched_entity *se)
+{
+	for_each_sched_entity(se) {
+		if (SCHED_WARN_ON(!se->on_rq))
+			return;
+		if (se_is_idle(se))
+			return;
+		cfs_rq_of(se)->last = se;
+	}
+}
+
+static void set_next_buddy(struct sched_entity *se)
+{
+	for_each_sched_entity(se) {
+		if (SCHED_WARN_ON(!se->on_rq))
+			return;
+		if (se_is_idle(se))
+			return;
+		cfs_rq_of(se)->next = se;
+	}
+}
+
+static void set_skip_buddy(struct sched_entity *se)
+{
+	for_each_sched_entity(se)
+		cfs_rq_of(se)->skip = se;
+}
+
+/*
+ * Preempt the current task with a newly woken task if needed:
+ */
+static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
+{
+	struct task_struct *curr = rq->curr;
+	struct sched_entity *se = &curr->se, *pse = &p->se;
+	struct cfs_rq *cfs_rq = task_cfs_rq(curr);
+	int scale = cfs_rq->nr_running >= sched_nr_latency;
+	int next_buddy_marked = 0;
+	int cse_is_idle, pse_is_idle;
+
+	if (unlikely(se == pse))
+		return;
+
+	/*
+	 * This is possible from callers such as attach_tasks(), in which we
+	 * unconditionally check_preempt_curr() after an enqueue (which may have
+	 * lead to a throttle).  This both saves work and prevents false
+	 * next-buddy nomination below.
+	 */
+	if (unlikely(throttled_hierarchy(cfs_rq_of(pse))))
+		return;
+
+	if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) {
+		set_next_buddy(pse);
+		next_buddy_marked = 1;
+	}
+
+	/*
+	 * We can come here with TIF_NEED_RESCHED already set from new task
+	 * wake up path.
+	 *
+	 * Note: this also catches the edge-case of curr being in a throttled
+	 * group (e.g. via set_curr_task), since update_curr() (in the
+	 * enqueue of curr) will have resulted in resched being set.  This
+	 * prevents us from potentially nominating it as a false LAST_BUDDY
+	 * below.
+	 */
+	if (test_tsk_need_resched(curr))
+		return;
+
+	/* Idle tasks are by definition preempted by non-idle tasks. */
+	if (unlikely(task_has_idle_policy(curr)) &&
+	    likely(!task_has_idle_policy(p)))
+		goto preempt;
+
+	/*
+	 * Batch and idle tasks do not preempt non-idle tasks (their preemption
+	 * is driven by the tick):
+	 */
+	if (unlikely(p->policy != SCHED_NORMAL) || !sched_feat(WAKEUP_PREEMPTION))
+		return;
+
+	find_matching_se(&se, &pse);
+	WARN_ON_ONCE(!pse);
+
+	cse_is_idle = se_is_idle(se);
+	pse_is_idle = se_is_idle(pse);
+
+	/*
+	 * Preempt an idle group in favor of a non-idle group (and don't preempt
+	 * in the inverse case).
+	 */
+	if (cse_is_idle && !pse_is_idle)
+		goto preempt;
+	if (cse_is_idle != pse_is_idle)
+		return;
+
+	update_curr(cfs_rq_of(se));
+	if (wakeup_preempt_entity(se, pse) == 1) {
+		/*
+		 * Bias pick_next to pick the sched entity that is
+		 * triggering this preemption.
+		 */
+		if (!next_buddy_marked)
+			set_next_buddy(pse);
+		goto preempt;
+	}
+
+	return;
+
+preempt:
+	resched_curr(rq);
+	/*
+	 * Only set the backward buddy when the current task is still
+	 * on the rq. This can happen when a wakeup gets interleaved
+	 * with schedule on the ->pre_schedule() or idle_balance()
+	 * point, either of which can * drop the rq lock.
+	 *
+	 * Also, during early boot the idle thread is in the fair class,
+	 * for obvious reasons its a bad idea to schedule back to it.
+	 */
+	if (unlikely(!se->on_rq || curr == rq->idle))
+		return;
+
+	if (sched_feat(LAST_BUDDY) && scale && entity_is_task(se))
+		set_last_buddy(se);
+}
+
+#ifdef CONFIG_SMP
+static struct task_struct *pick_task_fair(struct rq *rq)
+{
+	struct sched_entity *se;
+	struct cfs_rq *cfs_rq;
+
+again:
+	cfs_rq = &rq->cfs;
+	if (!cfs_rq->nr_running)
+		return NULL;
+
+	do {
+		struct sched_entity *curr = cfs_rq->curr;
+
+		/* When we pick for a remote RQ, we'll not have done put_prev_entity() */
+		if (curr) {
+			if (curr->on_rq)
+				update_curr(cfs_rq);
+			else
+				curr = NULL;
+
+			if (unlikely(check_cfs_rq_runtime(cfs_rq)))
+				goto again;
+		}
+
+		se = pick_next_entity(cfs_rq, curr);
+		cfs_rq = group_cfs_rq(se);
+	} while (cfs_rq);
+
+	return task_of(se);
+}
+#endif
+
+struct task_struct *
+pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	struct cfs_rq *cfs_rq = &rq->cfs;
+	struct sched_entity *se;
+	struct task_struct *p;
+	int new_tasks;
+
+again:
+	if (!sched_fair_runnable(rq))
+		goto idle;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	if (!prev || prev->sched_class != &fair_sched_class)
+		goto simple;
+
+	/*
+	 * Because of the set_next_buddy() in dequeue_task_fair() it is rather
+	 * likely that a next task is from the same cgroup as the current.
+	 *
+	 * Therefore attempt to avoid putting and setting the entire cgroup
+	 * hierarchy, only change the part that actually changes.
+	 */
+
+	do {
+		struct sched_entity *curr = cfs_rq->curr;
+
+		/*
+		 * Since we got here without doing put_prev_entity() we also
+		 * have to consider cfs_rq->curr. If it is still a runnable
+		 * entity, update_curr() will update its vruntime, otherwise
+		 * forget we've ever seen it.
+		 */
+		if (curr) {
+			if (curr->on_rq)
+				update_curr(cfs_rq);
+			else
+				curr = NULL;
+
+			/*
+			 * This call to check_cfs_rq_runtime() will do the
+			 * throttle and dequeue its entity in the parent(s).
+			 * Therefore the nr_running test will indeed
+			 * be correct.
+			 */
+			if (unlikely(check_cfs_rq_runtime(cfs_rq))) {
+				cfs_rq = &rq->cfs;
+
+				if (!cfs_rq->nr_running)
+					goto idle;
+
+				goto simple;
+			}
+		}
+
+		se = pick_next_entity(cfs_rq, curr);
+		cfs_rq = group_cfs_rq(se);
+	} while (cfs_rq);
+
+	p = task_of(se);
+
+	/*
+	 * Since we haven't yet done put_prev_entity and if the selected task
+	 * is a different task than we started out with, try and touch the
+	 * least amount of cfs_rqs.
+	 */
+	if (prev != p) {
+		struct sched_entity *pse = &prev->se;
+
+		while (!(cfs_rq = is_same_group(se, pse))) {
+			int se_depth = se->depth;
+			int pse_depth = pse->depth;
+
+			if (se_depth <= pse_depth) {
+				put_prev_entity(cfs_rq_of(pse), pse);
+				pse = parent_entity(pse);
+			}
+			if (se_depth >= pse_depth) {
+				set_next_entity(cfs_rq_of(se), se);
+				se = parent_entity(se);
+			}
+		}
+
+		put_prev_entity(cfs_rq, pse);
+		set_next_entity(cfs_rq, se);
+	}
+
+	goto done;
+simple:
+#endif
+	if (prev)
+		put_prev_task(rq, prev);
+
+	do {
+		se = pick_next_entity(cfs_rq, NULL);
+		set_next_entity(cfs_rq, se);
+		cfs_rq = group_cfs_rq(se);
+	} while (cfs_rq);
+
+	p = task_of(se);
+
+done: __maybe_unused;
+#ifdef CONFIG_SMP
+	/*
+	 * Move the next running task to the front of
+	 * the list, so our cfs_tasks list becomes MRU
+	 * one.
+	 */
+	list_move(&p->se.group_node, &rq->cfs_tasks);
+#endif
+
+	if (hrtick_enabled_fair(rq))
+		hrtick_start_fair(rq, p);
+
+	update_misfit_status(p, rq);
+
+	return p;
+
+idle:
+	if (!rf)
+		return NULL;
+
+	new_tasks = newidle_balance(rq, rf);
+
+	/*
+	 * Because newidle_balance() releases (and re-acquires) rq->lock, it is
+	 * possible for any higher priority task to appear. In that case we
+	 * must re-start the pick_next_entity() loop.
+	 */
+	if (new_tasks < 0)
+		return RETRY_TASK;
+
+	if (new_tasks > 0)
+		goto again;
+
+	/*
+	 * rq is about to be idle, check if we need to update the
+	 * lost_idle_time of clock_pelt
+	 */
+	update_idle_rq_clock_pelt(rq);
+
+	return NULL;
+}
+
+static struct task_struct *__pick_next_task_fair(struct rq *rq)
+{
+	return pick_next_task_fair(rq, NULL, NULL);
+}
+
+/*
+ * Account for a descheduled task:
+ */
+static void put_prev_task_fair(struct rq *rq, struct task_struct *prev)
+{
+	struct sched_entity *se = &prev->se;
+	struct cfs_rq *cfs_rq;
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+		put_prev_entity(cfs_rq, se);
+	}
+}
+
+/*
+ * sched_yield() is very simple
+ *
+ * The magic of dealing with the ->skip buddy is in pick_next_entity.
+ */
+static void yield_task_fair(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+	struct cfs_rq *cfs_rq = task_cfs_rq(curr);
+	struct sched_entity *se = &curr->se;
+
+	/*
+	 * Are we the only task in the tree?
+	 */
+	if (unlikely(rq->nr_running == 1))
+		return;
+
+	clear_buddies(cfs_rq, se);
+
+	if (curr->policy != SCHED_BATCH) {
+		update_rq_clock(rq);
+		/*
+		 * Update run-time statistics of the 'current'.
+		 */
+		update_curr(cfs_rq);
+		/*
+		 * Tell update_rq_clock() that we've just updated,
+		 * so we don't do microscopic update in schedule()
+		 * and double the fastpath cost.
+		 */
+		rq_clock_skip_update(rq);
+	}
+
+	set_skip_buddy(se);
+}
+
+static bool yield_to_task_fair(struct rq *rq, struct task_struct *p)
+{
+	struct sched_entity *se = &p->se;
+
+	/* throttled hierarchies are not runnable */
+	if (!se->on_rq || throttled_hierarchy(cfs_rq_of(se)))
+		return false;
+
+	/* Tell the scheduler that we'd really like pse to run next. */
+	set_next_buddy(se);
+
+	yield_task_fair(rq);
+
+	return true;
+}
+
+#ifdef CONFIG_SMP
+/**************************************************
+ * Fair scheduling class load-balancing methods.
+ *
+ * BASICS
+ *
+ * The purpose of load-balancing is to achieve the same basic fairness the
+ * per-CPU scheduler provides, namely provide a proportional amount of compute
+ * time to each task. This is expressed in the following equation:
+ *
+ *   W_i,n/P_i == W_j,n/P_j for all i,j                               (1)
+ *
+ * Where W_i,n is the n-th weight average for CPU i. The instantaneous weight
+ * W_i,0 is defined as:
+ *
+ *   W_i,0 = \Sum_j w_i,j                                             (2)
+ *
+ * Where w_i,j is the weight of the j-th runnable task on CPU i. This weight
+ * is derived from the nice value as per sched_prio_to_weight[].
+ *
+ * The weight average is an exponential decay average of the instantaneous
+ * weight:
+ *
+ *   W'_i,n = (2^n - 1) / 2^n * W_i,n + 1 / 2^n * W_i,0               (3)
+ *
+ * C_i is the compute capacity of CPU i, typically it is the
+ * fraction of 'recent' time available for SCHED_OTHER task execution. But it
+ * can also include other factors [XXX].
+ *
+ * To achieve this balance we define a measure of imbalance which follows
+ * directly from (1):
+ *
+ *   imb_i,j = max{ avg(W/C), W_i/C_i } - min{ avg(W/C), W_j/C_j }    (4)
+ *
+ * We them move tasks around to minimize the imbalance. In the continuous
+ * function space it is obvious this converges, in the discrete case we get
+ * a few fun cases generally called infeasible weight scenarios.
+ *
+ * [XXX expand on:
+ *     - infeasible weights;
+ *     - local vs global optima in the discrete case. ]
+ *
+ *
+ * SCHED DOMAINS
+ *
+ * In order to solve the imbalance equation (4), and avoid the obvious O(n^2)
+ * for all i,j solution, we create a tree of CPUs that follows the hardware
+ * topology where each level pairs two lower groups (or better). This results
+ * in O(log n) layers. Furthermore we reduce the number of CPUs going up the
+ * tree to only the first of the previous level and we decrease the frequency
+ * of load-balance at each level inv. proportional to the number of CPUs in
+ * the groups.
+ *
+ * This yields:
+ *
+ *     log_2 n     1     n
+ *   \Sum       { --- * --- * 2^i } = O(n)                            (5)
+ *     i = 0      2^i   2^i
+ *                               `- size of each group
+ *         |         |     `- number of CPUs doing load-balance
+ *         |         `- freq
+ *         `- sum over all levels
+ *
+ * Coupled with a limit on how many tasks we can migrate every balance pass,
+ * this makes (5) the runtime complexity of the balancer.
+ *
+ * An important property here is that each CPU is still (indirectly) connected
+ * to every other CPU in at most O(log n) steps:
+ *
+ * The adjacency matrix of the resulting graph is given by:
+ *
+ *             log_2 n
+ *   A_i,j = \Union     (i % 2^k == 0) && i / 2^(k+1) == j / 2^(k+1)  (6)
+ *             k = 0
+ *
+ * And you'll find that:
+ *
+ *   A^(log_2 n)_i,j != 0  for all i,j                                (7)
+ *
+ * Showing there's indeed a path between every CPU in at most O(log n) steps.
+ * The task movement gives a factor of O(m), giving a convergence complexity
+ * of:
+ *
+ *   O(nm log n),  n := nr_cpus, m := nr_tasks                        (8)
+ *
+ *
+ * WORK CONSERVING
+ *
+ * In order to avoid CPUs going idle while there's still work to do, new idle
+ * balancing is more aggressive and has the newly idle CPU iterate up the domain
+ * tree itself instead of relying on other CPUs to bring it work.
+ *
+ * This adds some complexity to both (5) and (8) but it reduces the total idle
+ * time.
+ *
+ * [XXX more?]
+ *
+ *
+ * CGROUPS
+ *
+ * Cgroups make a horror show out of (2), instead of a simple sum we get:
+ *
+ *                                s_k,i
+ *   W_i,0 = \Sum_j \Prod_k w_k * -----                               (9)
+ *                                 S_k
+ *
+ * Where
+ *
+ *   s_k,i = \Sum_j w_i,j,k  and  S_k = \Sum_i s_k,i                 (10)
+ *
+ * w_i,j,k is the weight of the j-th runnable task in the k-th cgroup on CPU i.
+ *
+ * The big problem is S_k, its a global sum needed to compute a local (W_i)
+ * property.
+ *
+ * [XXX write more on how we solve this.. _after_ merging pjt's patches that
+ *      rewrite all of this once again.]
+ */
+
+static unsigned long __read_mostly max_load_balance_interval = HZ/10;
+
+enum fbq_type { regular, remote, all };
+
+/*
+ * 'group_type' describes the group of CPUs at the moment of load balancing.
+ *
+ * The enum is ordered by pulling priority, with the group with lowest priority
+ * first so the group_type can simply be compared when selecting the busiest
+ * group. See update_sd_pick_busiest().
+ */
+enum group_type {
+	/* The group has spare capacity that can be used to run more tasks.  */
+	group_has_spare = 0,
+	/*
+	 * The group is fully used and the tasks don't compete for more CPU
+	 * cycles. Nevertheless, some tasks might wait before running.
+	 */
+	group_fully_busy,
+	/*
+	 * One task doesn't fit with CPU's capacity and must be migrated to a
+	 * more powerful CPU.
+	 */
+	group_misfit_task,
+	/*
+	 * SD_ASYM_PACKING only: One local CPU with higher capacity is available,
+	 * and the task should be migrated to it instead of running on the
+	 * current CPU.
+	 */
+	group_asym_packing,
+	/*
+	 * The tasks' affinity constraints previously prevented the scheduler
+	 * from balancing the load across the system.
+	 */
+	group_imbalanced,
+	/*
+	 * The CPU is overloaded and can't provide expected CPU cycles to all
+	 * tasks.
+	 */
+	group_overloaded
+};
+
+enum migration_type {
+	migrate_load = 0,
+	migrate_util,
+	migrate_task,
+	migrate_misfit
+};
+
+#define LBF_ALL_PINNED	0x01
+#define LBF_NEED_BREAK	0x02
+#define LBF_DST_PINNED  0x04
+#define LBF_SOME_PINNED	0x08
+#define LBF_ACTIVE_LB	0x10
+
+struct lb_env {
+	struct sched_domain	*sd;
+
+	struct rq		*src_rq;
+	int			src_cpu;
+
+	int			dst_cpu;
+	struct rq		*dst_rq;
+
+	struct cpumask		*dst_grpmask;
+	int			new_dst_cpu;
+	enum cpu_idle_type	idle;
+	long			imbalance;
+	/* The set of CPUs under consideration for load-balancing */
+	struct cpumask		*cpus;
+
+	unsigned int		flags;
+
+	unsigned int		loop;
+	unsigned int		loop_break;
+	unsigned int		loop_max;
+
+	enum fbq_type		fbq_type;
+	enum migration_type	migration_type;
+	struct list_head	tasks;
+};
+
+/*
+ * Is this task likely cache-hot:
+ */
+static int task_hot(struct task_struct *p, struct lb_env *env)
+{
+	s64 delta;
+
+	lockdep_assert_rq_held(env->src_rq);
+
+	if (p->sched_class != &fair_sched_class)
+		return 0;
+
+	if (unlikely(task_has_idle_policy(p)))
+		return 0;
+
+	/* SMT siblings share cache */
+	if (env->sd->flags & SD_SHARE_CPUCAPACITY)
+		return 0;
+
+	/*
+	 * Buddy candidates are cache hot:
+	 */
+	if (sched_feat(CACHE_HOT_BUDDY) && env->dst_rq->nr_running &&
+			(&p->se == cfs_rq_of(&p->se)->next ||
+			 &p->se == cfs_rq_of(&p->se)->last))
+		return 1;
+
+	if (sysctl_sched_migration_cost == -1)
+		return 1;
+
+	/*
+	 * Don't migrate task if the task's cookie does not match
+	 * with the destination CPU's core cookie.
+	 */
+	if (!sched_core_cookie_match(cpu_rq(env->dst_cpu), p))
+		return 1;
+
+	if (sysctl_sched_migration_cost == 0)
+		return 0;
+
+	delta = rq_clock_task(env->src_rq) - p->se.exec_start;
+
+	return delta < (s64)sysctl_sched_migration_cost;
+}
+
+#ifdef CONFIG_NUMA_BALANCING
+/*
+ * Returns 1, if task migration degrades locality
+ * Returns 0, if task migration improves locality i.e migration preferred.
+ * Returns -1, if task migration is not affected by locality.
+ */
+static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
+{
+	struct numa_group *numa_group = rcu_dereference(p->numa_group);
+	unsigned long src_weight, dst_weight;
+	int src_nid, dst_nid, dist;
+
+	if (!static_branch_likely(&sched_numa_balancing))
+		return -1;
+
+	if (!p->numa_faults || !(env->sd->flags & SD_NUMA))
+		return -1;
+
+	src_nid = cpu_to_node(env->src_cpu);
+	dst_nid = cpu_to_node(env->dst_cpu);
+
+	if (src_nid == dst_nid)
+		return -1;
+
+	/* Migrating away from the preferred node is always bad. */
+	if (src_nid == p->numa_preferred_nid) {
+		if (env->src_rq->nr_running > env->src_rq->nr_preferred_running)
+			return 1;
+		else
+			return -1;
+	}
+
+	/* Encourage migration to the preferred node. */
+	if (dst_nid == p->numa_preferred_nid)
+		return 0;
+
+	/* Leaving a core idle is often worse than degrading locality. */
+	if (env->idle == CPU_IDLE)
+		return -1;
+
+	dist = node_distance(src_nid, dst_nid);
+	if (numa_group) {
+		src_weight = group_weight(p, src_nid, dist);
+		dst_weight = group_weight(p, dst_nid, dist);
+	} else {
+		src_weight = task_weight(p, src_nid, dist);
+		dst_weight = task_weight(p, dst_nid, dist);
+	}
+
+	return dst_weight < src_weight;
+}
+
+#else
+static inline int migrate_degrades_locality(struct task_struct *p,
+					     struct lb_env *env)
+{
+	return -1;
+}
+#endif
+
+/*
+ * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
+ */
+static
+int can_migrate_task(struct task_struct *p, struct lb_env *env)
+{
+	int tsk_cache_hot;
+
+	lockdep_assert_rq_held(env->src_rq);
+
+	/*
+	 * We do not migrate tasks that are:
+	 * 1) throttled_lb_pair, or
+	 * 2) cannot be migrated to this CPU due to cpus_ptr, or
+	 * 3) running (obviously), or
+	 * 4) are cache-hot on their current CPU.
+	 */
+	if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu))
+		return 0;
+
+	/* Disregard pcpu kthreads; they are where they need to be. */
+	if (kthread_is_per_cpu(p))
+		return 0;
+
+	if (!cpumask_test_cpu(env->dst_cpu, p->cpus_ptr)) {
+		int cpu;
+
+		schedstat_inc(p->stats.nr_failed_migrations_affine);
+
+		env->flags |= LBF_SOME_PINNED;
+
+		/*
+		 * Remember if this task can be migrated to any other CPU in
+		 * our sched_group. We may want to revisit it if we couldn't
+		 * meet load balance goals by pulling other tasks on src_cpu.
+		 *
+		 * Avoid computing new_dst_cpu
+		 * - for NEWLY_IDLE
+		 * - if we have already computed one in current iteration
+		 * - if it's an active balance
+		 */
+		if (env->idle == CPU_NEWLY_IDLE ||
+		    env->flags & (LBF_DST_PINNED | LBF_ACTIVE_LB))
+			return 0;
+
+		/* Prevent to re-select dst_cpu via env's CPUs: */
+		for_each_cpu_and(cpu, env->dst_grpmask, env->cpus) {
+			if (cpumask_test_cpu(cpu, p->cpus_ptr)) {
+				env->flags |= LBF_DST_PINNED;
+				env->new_dst_cpu = cpu;
+				break;
+			}
+		}
+
+		return 0;
+	}
+
+	/* Record that we found at least one task that could run on dst_cpu */
+	env->flags &= ~LBF_ALL_PINNED;
+
+	if (task_on_cpu(env->src_rq, p)) {
+		schedstat_inc(p->stats.nr_failed_migrations_running);
+		return 0;
+	}
+
+	/*
+	 * Aggressive migration if:
+	 * 1) active balance
+	 * 2) destination numa is preferred
+	 * 3) task is cache cold, or
+	 * 4) too many balance attempts have failed.
+	 */
+	if (env->flags & LBF_ACTIVE_LB)
+		return 1;
+
+	tsk_cache_hot = migrate_degrades_locality(p, env);
+	if (tsk_cache_hot == -1)
+		tsk_cache_hot = task_hot(p, env);
+
+	if (tsk_cache_hot <= 0 ||
+	    env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
+		if (tsk_cache_hot == 1) {
+			schedstat_inc(env->sd->lb_hot_gained[env->idle]);
+			schedstat_inc(p->stats.nr_forced_migrations);
+		}
+		return 1;
+	}
+
+	schedstat_inc(p->stats.nr_failed_migrations_hot);
+	return 0;
+}
+
+/*
+ * detach_task() -- detach the task for the migration specified in env
+ */
+static void detach_task(struct task_struct *p, struct lb_env *env)
+{
+	lockdep_assert_rq_held(env->src_rq);
+
+	deactivate_task(env->src_rq, p, DEQUEUE_NOCLOCK);
+	set_task_cpu(p, env->dst_cpu);
+}
+
+/*
+ * detach_one_task() -- tries to dequeue exactly one task from env->src_rq, as
+ * part of active balancing operations within "domain".
+ *
+ * Returns a task if successful and NULL otherwise.
+ */
+static struct task_struct *detach_one_task(struct lb_env *env)
+{
+	struct task_struct *p;
+
+	lockdep_assert_rq_held(env->src_rq);
+
+	list_for_each_entry_reverse(p,
+			&env->src_rq->cfs_tasks, se.group_node) {
+		if (!can_migrate_task(p, env))
+			continue;
+
+		detach_task(p, env);
+
+		/*
+		 * Right now, this is only the second place where
+		 * lb_gained[env->idle] is updated (other is detach_tasks)
+		 * so we can safely collect stats here rather than
+		 * inside detach_tasks().
+		 */
+		schedstat_inc(env->sd->lb_gained[env->idle]);
+		return p;
+	}
+	return NULL;
+}
+
+/*
+ * detach_tasks() -- tries to detach up to imbalance load/util/tasks from
+ * busiest_rq, as part of a balancing operation within domain "sd".
+ *
+ * Returns number of detached tasks if successful and 0 otherwise.
+ */
+static int detach_tasks(struct lb_env *env)
+{
+	struct list_head *tasks = &env->src_rq->cfs_tasks;
+	unsigned long util, load;
+	struct task_struct *p;
+	int detached = 0;
+
+	lockdep_assert_rq_held(env->src_rq);
+
+	/*
+	 * Source run queue has been emptied by another CPU, clear
+	 * LBF_ALL_PINNED flag as we will not test any task.
+	 */
+	if (env->src_rq->nr_running <= 1) {
+		env->flags &= ~LBF_ALL_PINNED;
+		return 0;
+	}
+
+	if (env->imbalance <= 0)
+		return 0;
+
+	while (!list_empty(tasks)) {
+		/*
+		 * We don't want to steal all, otherwise we may be treated likewise,
+		 * which could at worst lead to a livelock crash.
+		 */
+		if (env->idle != CPU_NOT_IDLE && env->src_rq->nr_running <= 1)
+			break;
+
+		env->loop++;
+		/*
+		 * We've more or less seen every task there is, call it quits
+		 * unless we haven't found any movable task yet.
+		 */
+		if (env->loop > env->loop_max &&
+		    !(env->flags & LBF_ALL_PINNED))
+			break;
+
+		/* take a breather every nr_migrate tasks */
+		if (env->loop > env->loop_break) {
+			env->loop_break += SCHED_NR_MIGRATE_BREAK;
+			env->flags |= LBF_NEED_BREAK;
+			break;
+		}
+
+		p = list_last_entry(tasks, struct task_struct, se.group_node);
+
+		if (!can_migrate_task(p, env))
+			goto next;
+
+		switch (env->migration_type) {
+		case migrate_load:
+			/*
+			 * Depending of the number of CPUs and tasks and the
+			 * cgroup hierarchy, task_h_load() can return a null
+			 * value. Make sure that env->imbalance decreases
+			 * otherwise detach_tasks() will stop only after
+			 * detaching up to loop_max tasks.
+			 */
+			load = max_t(unsigned long, task_h_load(p), 1);
+
+			if (sched_feat(LB_MIN) &&
+			    load < 16 && !env->sd->nr_balance_failed)
+				goto next;
+
+			/*
+			 * Make sure that we don't migrate too much load.
+			 * Nevertheless, let relax the constraint if
+			 * scheduler fails to find a good waiting task to
+			 * migrate.
+			 */
+			if (shr_bound(load, env->sd->nr_balance_failed) > env->imbalance)
+				goto next;
+
+			env->imbalance -= load;
+			break;
+
+		case migrate_util:
+			util = task_util_est(p);
+
+			if (util > env->imbalance)
+				goto next;
+
+			env->imbalance -= util;
+			break;
+
+		case migrate_task:
+			env->imbalance--;
+			break;
+
+		case migrate_misfit:
+			/* This is not a misfit task */
+			if (task_fits_cpu(p, env->src_cpu))
+				goto next;
+
+			env->imbalance = 0;
+			break;
+		}
+
+		detach_task(p, env);
+		list_add(&p->se.group_node, &env->tasks);
+
+		detached++;
+
+#ifdef CONFIG_PREEMPTION
+		/*
+		 * NEWIDLE balancing is a source of latency, so preemptible
+		 * kernels will stop after the first task is detached to minimize
+		 * the critical section.
+		 */
+		if (env->idle == CPU_NEWLY_IDLE)
+			break;
+#endif
+
+		/*
+		 * We only want to steal up to the prescribed amount of
+		 * load/util/tasks.
+		 */
+		if (env->imbalance <= 0)
+			break;
+
+		continue;
+next:
+		list_move(&p->se.group_node, tasks);
+	}
+
+	/*
+	 * Right now, this is one of only two places we collect this stat
+	 * so we can safely collect detach_one_task() stats here rather
+	 * than inside detach_one_task().
+	 */
+	schedstat_add(env->sd->lb_gained[env->idle], detached);
+
+	return detached;
+}
+
+/*
+ * attach_task() -- attach the task detached by detach_task() to its new rq.
+ */
+static void attach_task(struct rq *rq, struct task_struct *p)
+{
+	lockdep_assert_rq_held(rq);
+
+	WARN_ON_ONCE(task_rq(p) != rq);
+	activate_task(rq, p, ENQUEUE_NOCLOCK);
+	check_preempt_curr(rq, p, 0);
+}
+
+/*
+ * attach_one_task() -- attaches the task returned from detach_one_task() to
+ * its new rq.
+ */
+static void attach_one_task(struct rq *rq, struct task_struct *p)
+{
+	struct rq_flags rf;
+
+	rq_lock(rq, &rf);
+	update_rq_clock(rq);
+	attach_task(rq, p);
+	rq_unlock(rq, &rf);
+}
+
+/*
+ * attach_tasks() -- attaches all tasks detached by detach_tasks() to their
+ * new rq.
+ */
+static void attach_tasks(struct lb_env *env)
+{
+	struct list_head *tasks = &env->tasks;
+	struct task_struct *p;
+	struct rq_flags rf;
+
+	rq_lock(env->dst_rq, &rf);
+	update_rq_clock(env->dst_rq);
+
+	while (!list_empty(tasks)) {
+		p = list_first_entry(tasks, struct task_struct, se.group_node);
+		list_del_init(&p->se.group_node);
+
+		attach_task(env->dst_rq, p);
+	}
+
+	rq_unlock(env->dst_rq, &rf);
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+static inline bool cfs_rq_has_blocked(struct cfs_rq *cfs_rq)
+{
+	if (cfs_rq->avg.load_avg)
+		return true;
+
+	if (cfs_rq->avg.util_avg)
+		return true;
+
+	return false;
+}
+
+static inline bool others_have_blocked(struct rq *rq)
+{
+	if (READ_ONCE(rq->avg_rt.util_avg))
+		return true;
+
+	if (READ_ONCE(rq->avg_dl.util_avg))
+		return true;
+
+	if (thermal_load_avg(rq))
+		return true;
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+	if (READ_ONCE(rq->avg_irq.util_avg))
+		return true;
+#endif
+
+	return false;
+}
+
+static inline void update_blocked_load_tick(struct rq *rq)
+{
+	WRITE_ONCE(rq->last_blocked_load_update_tick, jiffies);
+}
+
+static inline void update_blocked_load_status(struct rq *rq, bool has_blocked)
+{
+	if (!has_blocked)
+		rq->has_blocked_load = 0;
+}
+#else
+static inline bool cfs_rq_has_blocked(struct cfs_rq *cfs_rq) { return false; }
+static inline bool others_have_blocked(struct rq *rq) { return false; }
+static inline void update_blocked_load_tick(struct rq *rq) {}
+static inline void update_blocked_load_status(struct rq *rq, bool has_blocked) {}
+#endif
+
+static bool __update_blocked_others(struct rq *rq, bool *done)
+{
+	const struct sched_class *curr_class;
+	u64 now = rq_clock_pelt(rq);
+	unsigned long thermal_pressure;
+	bool decayed;
+
+	/*
+	 * update_load_avg() can call cpufreq_update_util(). Make sure that RT,
+	 * DL and IRQ signals have been updated before updating CFS.
+	 */
+	curr_class = rq->curr->sched_class;
+
+	thermal_pressure = arch_scale_thermal_pressure(cpu_of(rq));
+
+	decayed = update_rt_rq_load_avg(now, rq, curr_class == &rt_sched_class) |
+		  update_dl_rq_load_avg(now, rq, curr_class == &dl_sched_class) |
+		  update_thermal_load_avg(rq_clock_thermal(rq), rq, thermal_pressure) |
+		  update_irq_load_avg(rq, 0);
+
+	if (others_have_blocked(rq))
+		*done = false;
+
+	return decayed;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+static bool __update_blocked_fair(struct rq *rq, bool *done)
+{
+	struct cfs_rq *cfs_rq, *pos;
+	bool decayed = false;
+	int cpu = cpu_of(rq);
+
+	/*
+	 * Iterates the task_group tree in a bottom up fashion, see
+	 * list_add_leaf_cfs_rq() for details.
+	 */
+	for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) {
+		struct sched_entity *se;
+
+		if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) {
+			update_tg_load_avg(cfs_rq);
+
+			if (cfs_rq->nr_running == 0)
+				update_idle_cfs_rq_clock_pelt(cfs_rq);
+
+			if (cfs_rq == &rq->cfs)
+				decayed = true;
+		}
+
+		/* Propagate pending load changes to the parent, if any: */
+		se = cfs_rq->tg->se[cpu];
+		if (se && !skip_blocked_update(se))
+			update_load_avg(cfs_rq_of(se), se, UPDATE_TG);
+
+		/*
+		 * There can be a lot of idle CPU cgroups.  Don't let fully
+		 * decayed cfs_rqs linger on the list.
+		 */
+		if (cfs_rq_is_decayed(cfs_rq))
+			list_del_leaf_cfs_rq(cfs_rq);
+
+		/* Don't need periodic decay once load/util_avg are null */
+		if (cfs_rq_has_blocked(cfs_rq))
+			*done = false;
+	}
+
+	return decayed;
+}
+
+/*
+ * Compute the hierarchical load factor for cfs_rq and all its ascendants.
+ * This needs to be done in a top-down fashion because the load of a child
+ * group is a fraction of its parents load.
+ */
+static void update_cfs_rq_h_load(struct cfs_rq *cfs_rq)
+{
+	struct rq *rq = rq_of(cfs_rq);
+	struct sched_entity *se = cfs_rq->tg->se[cpu_of(rq)];
+	unsigned long now = jiffies;
+	unsigned long load;
+
+	if (cfs_rq->last_h_load_update == now)
+		return;
+
+	WRITE_ONCE(cfs_rq->h_load_next, NULL);
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+		WRITE_ONCE(cfs_rq->h_load_next, se);
+		if (cfs_rq->last_h_load_update == now)
+			break;
+	}
+
+	if (!se) {
+		cfs_rq->h_load = cfs_rq_load_avg(cfs_rq);
+		cfs_rq->last_h_load_update = now;
+	}
+
+	while ((se = READ_ONCE(cfs_rq->h_load_next)) != NULL) {
+		load = cfs_rq->h_load;
+		load = div64_ul(load * se->avg.load_avg,
+			cfs_rq_load_avg(cfs_rq) + 1);
+		cfs_rq = group_cfs_rq(se);
+		cfs_rq->h_load = load;
+		cfs_rq->last_h_load_update = now;
+	}
+}
+
+static unsigned long task_h_load(struct task_struct *p)
+{
+	struct cfs_rq *cfs_rq = task_cfs_rq(p);
+
+	update_cfs_rq_h_load(cfs_rq);
+	return div64_ul(p->se.avg.load_avg * cfs_rq->h_load,
+			cfs_rq_load_avg(cfs_rq) + 1);
+}
+#else
+static bool __update_blocked_fair(struct rq *rq, bool *done)
+{
+	struct cfs_rq *cfs_rq = &rq->cfs;
+	bool decayed;
+
+	decayed = update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq);
+	if (cfs_rq_has_blocked(cfs_rq))
+		*done = false;
+
+	return decayed;
+}
+
+static unsigned long task_h_load(struct task_struct *p)
+{
+	return p->se.avg.load_avg;
+}
+#endif
+
+static void update_blocked_averages(int cpu)
+{
+	bool decayed = false, done = true;
+	struct rq *rq = cpu_rq(cpu);
+	struct rq_flags rf;
+
+	rq_lock_irqsave(rq, &rf);
+	update_blocked_load_tick(rq);
+	update_rq_clock(rq);
+
+	decayed |= __update_blocked_others(rq, &done);
+	decayed |= __update_blocked_fair(rq, &done);
+
+	update_blocked_load_status(rq, !done);
+	if (decayed)
+		cpufreq_update_util(rq, 0);
+	rq_unlock_irqrestore(rq, &rf);
+}
+
+/********** Helpers for find_busiest_group ************************/
+
+/*
+ * sg_lb_stats - stats of a sched_group required for load_balancing
+ */
+struct sg_lb_stats {
+	unsigned long avg_load; /*Avg load across the CPUs of the group */
+	unsigned long group_load; /* Total load over the CPUs of the group */
+	unsigned long group_capacity;
+	unsigned long group_util; /* Total utilization over the CPUs of the group */
+	unsigned long group_runnable; /* Total runnable time over the CPUs of the group */
+	unsigned int sum_nr_running; /* Nr of tasks running in the group */
+	unsigned int sum_h_nr_running; /* Nr of CFS tasks running in the group */
+	unsigned int idle_cpus;
+	unsigned int group_weight;
+	enum group_type group_type;
+	unsigned int group_asym_packing; /* Tasks should be moved to preferred CPU */
+	unsigned long group_misfit_task_load; /* A CPU has a task too big for its capacity */
+#ifdef CONFIG_NUMA_BALANCING
+	unsigned int nr_numa_running;
+	unsigned int nr_preferred_running;
+#endif
+};
+
+/*
+ * sd_lb_stats - Structure to store the statistics of a sched_domain
+ *		 during load balancing.
+ */
+struct sd_lb_stats {
+	struct sched_group *busiest;	/* Busiest group in this sd */
+	struct sched_group *local;	/* Local group in this sd */
+	unsigned long total_load;	/* Total load of all groups in sd */
+	unsigned long total_capacity;	/* Total capacity of all groups in sd */
+	unsigned long avg_load;	/* Average load across all groups in sd */
+	unsigned int prefer_sibling; /* tasks should go to sibling first */
+
+	struct sg_lb_stats busiest_stat;/* Statistics of the busiest group */
+	struct sg_lb_stats local_stat;	/* Statistics of the local group */
+};
+
+static inline void init_sd_lb_stats(struct sd_lb_stats *sds)
+{
+	/*
+	 * Skimp on the clearing to avoid duplicate work. We can avoid clearing
+	 * local_stat because update_sg_lb_stats() does a full clear/assignment.
+	 * We must however set busiest_stat::group_type and
+	 * busiest_stat::idle_cpus to the worst busiest group because
+	 * update_sd_pick_busiest() reads these before assignment.
+	 */
+	*sds = (struct sd_lb_stats){
+		.busiest = NULL,
+		.local = NULL,
+		.total_load = 0UL,
+		.total_capacity = 0UL,
+		.busiest_stat = {
+			.idle_cpus = UINT_MAX,
+			.group_type = group_has_spare,
+		},
+	};
+}
+
+static unsigned long scale_rt_capacity(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long max = arch_scale_cpu_capacity(cpu);
+	unsigned long used, free;
+	unsigned long irq;
+
+	irq = cpu_util_irq(rq);
+
+	if (unlikely(irq >= max))
+		return 1;
+
+	/*
+	 * avg_rt.util_avg and avg_dl.util_avg track binary signals
+	 * (running and not running) with weights 0 and 1024 respectively.
+	 * avg_thermal.load_avg tracks thermal pressure and the weighted
+	 * average uses the actual delta max capacity(load).
+	 */
+	used = READ_ONCE(rq->avg_rt.util_avg);
+	used += READ_ONCE(rq->avg_dl.util_avg);
+	used += thermal_load_avg(rq);
+
+	if (unlikely(used >= max))
+		return 1;
+
+	free = max - used;
+
+	return scale_irq_capacity(free, irq, max);
+}
+
+static void update_cpu_capacity(struct sched_domain *sd, int cpu)
+{
+	unsigned long capacity = scale_rt_capacity(cpu);
+	struct sched_group *sdg = sd->groups;
+
+	cpu_rq(cpu)->cpu_capacity_orig = arch_scale_cpu_capacity(cpu);
+
+	if (!capacity)
+		capacity = 1;
+
+	cpu_rq(cpu)->cpu_capacity = capacity;
+	trace_sched_cpu_capacity_tp(cpu_rq(cpu));
+
+	sdg->sgc->capacity = capacity;
+	sdg->sgc->min_capacity = capacity;
+	sdg->sgc->max_capacity = capacity;
+}
+
+void update_group_capacity(struct sched_domain *sd, int cpu)
+{
+	struct sched_domain *child = sd->child;
+	struct sched_group *group, *sdg = sd->groups;
+	unsigned long capacity, min_capacity, max_capacity;
+	unsigned long interval;
+
+	interval = msecs_to_jiffies(sd->balance_interval);
+	interval = clamp(interval, 1UL, max_load_balance_interval);
+	sdg->sgc->next_update = jiffies + interval;
+
+	if (!child) {
+		update_cpu_capacity(sd, cpu);
+		return;
+	}
+
+	capacity = 0;
+	min_capacity = ULONG_MAX;
+	max_capacity = 0;
+
+	if (child->flags & SD_OVERLAP) {
+		/*
+		 * SD_OVERLAP domains cannot assume that child groups
+		 * span the current group.
+		 */
+
+		for_each_cpu(cpu, sched_group_span(sdg)) {
+			unsigned long cpu_cap = capacity_of(cpu);
+
+			capacity += cpu_cap;
+			min_capacity = min(cpu_cap, min_capacity);
+			max_capacity = max(cpu_cap, max_capacity);
+		}
+	} else  {
+		/*
+		 * !SD_OVERLAP domains can assume that child groups
+		 * span the current group.
+		 */
+
+		group = child->groups;
+		do {
+			struct sched_group_capacity *sgc = group->sgc;
+
+			capacity += sgc->capacity;
+			min_capacity = min(sgc->min_capacity, min_capacity);
+			max_capacity = max(sgc->max_capacity, max_capacity);
+			group = group->next;
+		} while (group != child->groups);
+	}
+
+	sdg->sgc->capacity = capacity;
+	sdg->sgc->min_capacity = min_capacity;
+	sdg->sgc->max_capacity = max_capacity;
+}
+
+/*
+ * Check whether the capacity of the rq has been noticeably reduced by side
+ * activity. The imbalance_pct is used for the threshold.
+ * Return true is the capacity is reduced
+ */
+static inline int
+check_cpu_capacity(struct rq *rq, struct sched_domain *sd)
+{
+	return ((rq->cpu_capacity * sd->imbalance_pct) <
+				(rq->cpu_capacity_orig * 100));
+}
+
+/*
+ * Check whether a rq has a misfit task and if it looks like we can actually
+ * help that task: we can migrate the task to a CPU of higher capacity, or
+ * the task's current CPU is heavily pressured.
+ */
+static inline int check_misfit_status(struct rq *rq, struct sched_domain *sd)
+{
+	return rq->misfit_task_load &&
+		(rq->cpu_capacity_orig < rq->rd->max_cpu_capacity ||
+		 check_cpu_capacity(rq, sd));
+}
+
+/*
+ * Group imbalance indicates (and tries to solve) the problem where balancing
+ * groups is inadequate due to ->cpus_ptr constraints.
+ *
+ * Imagine a situation of two groups of 4 CPUs each and 4 tasks each with a
+ * cpumask covering 1 CPU of the first group and 3 CPUs of the second group.
+ * Something like:
+ *
+ *	{ 0 1 2 3 } { 4 5 6 7 }
+ *	        *     * * *
+ *
+ * If we were to balance group-wise we'd place two tasks in the first group and
+ * two tasks in the second group. Clearly this is undesired as it will overload
+ * cpu 3 and leave one of the CPUs in the second group unused.
+ *
+ * The current solution to this issue is detecting the skew in the first group
+ * by noticing the lower domain failed to reach balance and had difficulty
+ * moving tasks due to affinity constraints.
+ *
+ * When this is so detected; this group becomes a candidate for busiest; see
+ * update_sd_pick_busiest(). And calculate_imbalance() and
+ * find_busiest_group() avoid some of the usual balance conditions to allow it
+ * to create an effective group imbalance.
+ *
+ * This is a somewhat tricky proposition since the next run might not find the
+ * group imbalance and decide the groups need to be balanced again. A most
+ * subtle and fragile situation.
+ */
+
+static inline int sg_imbalanced(struct sched_group *group)
+{
+	return group->sgc->imbalance;
+}
+
+/*
+ * group_has_capacity returns true if the group has spare capacity that could
+ * be used by some tasks.
+ * We consider that a group has spare capacity if the number of task is
+ * smaller than the number of CPUs or if the utilization is lower than the
+ * available capacity for CFS tasks.
+ * For the latter, we use a threshold to stabilize the state, to take into
+ * account the variance of the tasks' load and to return true if the available
+ * capacity in meaningful for the load balancer.
+ * As an example, an available capacity of 1% can appear but it doesn't make
+ * any benefit for the load balance.
+ */
+static inline bool
+group_has_capacity(unsigned int imbalance_pct, struct sg_lb_stats *sgs)
+{
+	if (sgs->sum_nr_running < sgs->group_weight)
+		return true;
+
+	if ((sgs->group_capacity * imbalance_pct) <
+			(sgs->group_runnable * 100))
+		return false;
+
+	if ((sgs->group_capacity * 100) >
+			(sgs->group_util * imbalance_pct))
+		return true;
+
+	return false;
+}
+
+/*
+ *  group_is_overloaded returns true if the group has more tasks than it can
+ *  handle.
+ *  group_is_overloaded is not equals to !group_has_capacity because a group
+ *  with the exact right number of tasks, has no more spare capacity but is not
+ *  overloaded so both group_has_capacity and group_is_overloaded return
+ *  false.
+ */
+static inline bool
+group_is_overloaded(unsigned int imbalance_pct, struct sg_lb_stats *sgs)
+{
+	if (sgs->sum_nr_running <= sgs->group_weight)
+		return false;
+
+	if ((sgs->group_capacity * 100) <
+			(sgs->group_util * imbalance_pct))
+		return true;
+
+	if ((sgs->group_capacity * imbalance_pct) <
+			(sgs->group_runnable * 100))
+		return true;
+
+	return false;
+}
+
+static inline enum
+group_type group_classify(unsigned int imbalance_pct,
+			  struct sched_group *group,
+			  struct sg_lb_stats *sgs)
+{
+	if (group_is_overloaded(imbalance_pct, sgs))
+		return group_overloaded;
+
+	if (sg_imbalanced(group))
+		return group_imbalanced;
+
+	if (sgs->group_asym_packing)
+		return group_asym_packing;
+
+	if (sgs->group_misfit_task_load)
+		return group_misfit_task;
+
+	if (!group_has_capacity(imbalance_pct, sgs))
+		return group_fully_busy;
+
+	return group_has_spare;
+}
+
+/**
+ * asym_smt_can_pull_tasks - Check whether the load balancing CPU can pull tasks
+ * @dst_cpu:	Destination CPU of the load balancing
+ * @sds:	Load-balancing data with statistics of the local group
+ * @sgs:	Load-balancing statistics of the candidate busiest group
+ * @sg:		The candidate busiest group
+ *
+ * Check the state of the SMT siblings of both @sds::local and @sg and decide
+ * if @dst_cpu can pull tasks.
+ *
+ * If @dst_cpu does not have SMT siblings, it can pull tasks if two or more of
+ * the SMT siblings of @sg are busy. If only one CPU in @sg is busy, pull tasks
+ * only if @dst_cpu has higher priority.
+ *
+ * If both @dst_cpu and @sg have SMT siblings, and @sg has exactly one more
+ * busy CPU than @sds::local, let @dst_cpu pull tasks if it has higher priority.
+ * Bigger imbalances in the number of busy CPUs will be dealt with in
+ * update_sd_pick_busiest().
+ *
+ * If @sg does not have SMT siblings, only pull tasks if all of the SMT siblings
+ * of @dst_cpu are idle and @sg has lower priority.
+ *
+ * Return: true if @dst_cpu can pull tasks, false otherwise.
+ */
+static bool asym_smt_can_pull_tasks(int dst_cpu, struct sd_lb_stats *sds,
+				    struct sg_lb_stats *sgs,
+				    struct sched_group *sg)
+{
+#ifdef CONFIG_SCHED_SMT
+	bool local_is_smt, sg_is_smt;
+	int sg_busy_cpus;
+
+	local_is_smt = sds->local->flags & SD_SHARE_CPUCAPACITY;
+	sg_is_smt = sg->flags & SD_SHARE_CPUCAPACITY;
+
+	sg_busy_cpus = sgs->group_weight - sgs->idle_cpus;
+
+	if (!local_is_smt) {
+		/*
+		 * If we are here, @dst_cpu is idle and does not have SMT
+		 * siblings. Pull tasks if candidate group has two or more
+		 * busy CPUs.
+		 */
+		if (sg_busy_cpus >= 2) /* implies sg_is_smt */
+			return true;
+
+		/*
+		 * @dst_cpu does not have SMT siblings. @sg may have SMT
+		 * siblings and only one is busy. In such case, @dst_cpu
+		 * can help if it has higher priority and is idle (i.e.,
+		 * it has no running tasks).
+		 */
+		return sched_asym_prefer(dst_cpu, sg->asym_prefer_cpu);
+	}
+
+	/* @dst_cpu has SMT siblings. */
+
+	if (sg_is_smt) {
+		int local_busy_cpus = sds->local->group_weight -
+				      sds->local_stat.idle_cpus;
+		int busy_cpus_delta = sg_busy_cpus - local_busy_cpus;
+
+		if (busy_cpus_delta == 1)
+			return sched_asym_prefer(dst_cpu, sg->asym_prefer_cpu);
+
+		return false;
+	}
+
+	/*
+	 * @sg does not have SMT siblings. Ensure that @sds::local does not end
+	 * up with more than one busy SMT sibling and only pull tasks if there
+	 * are not busy CPUs (i.e., no CPU has running tasks).
+	 */
+	if (!sds->local_stat.sum_nr_running)
+		return sched_asym_prefer(dst_cpu, sg->asym_prefer_cpu);
+
+	return false;
+#else
+	/* Always return false so that callers deal with non-SMT cases. */
+	return false;
+#endif
+}
+
+static inline bool
+sched_asym(struct lb_env *env, struct sd_lb_stats *sds,  struct sg_lb_stats *sgs,
+	   struct sched_group *group)
+{
+	/* Only do SMT checks if either local or candidate have SMT siblings */
+	if ((sds->local->flags & SD_SHARE_CPUCAPACITY) ||
+	    (group->flags & SD_SHARE_CPUCAPACITY))
+		return asym_smt_can_pull_tasks(env->dst_cpu, sds, sgs, group);
+
+	return sched_asym_prefer(env->dst_cpu, group->asym_prefer_cpu);
+}
+
+static inline bool
+sched_reduced_capacity(struct rq *rq, struct sched_domain *sd)
+{
+	/*
+	 * When there is more than 1 task, the group_overloaded case already
+	 * takes care of cpu with reduced capacity
+	 */
+	if (rq->cfs.h_nr_running != 1)
+		return false;
+
+	return check_cpu_capacity(rq, sd);
+}
+
+/**
+ * update_sg_lb_stats - Update sched_group's statistics for load balancing.
+ * @env: The load balancing environment.
+ * @sds: Load-balancing data with statistics of the local group.
+ * @group: sched_group whose statistics are to be updated.
+ * @sgs: variable to hold the statistics for this group.
+ * @sg_status: Holds flag indicating the status of the sched_group
+ */
+static inline void update_sg_lb_stats(struct lb_env *env,
+				      struct sd_lb_stats *sds,
+				      struct sched_group *group,
+				      struct sg_lb_stats *sgs,
+				      int *sg_status)
+{
+	int i, nr_running, local_group;
+
+	memset(sgs, 0, sizeof(*sgs));
+
+	local_group = group == sds->local;
+
+	for_each_cpu_and(i, sched_group_span(group), env->cpus) {
+		struct rq *rq = cpu_rq(i);
+		unsigned long load = cpu_load(rq);
+
+		sgs->group_load += load;
+		sgs->group_util += cpu_util_cfs(i);
+		sgs->group_runnable += cpu_runnable(rq);
+		sgs->sum_h_nr_running += rq->cfs.h_nr_running;
+
+		nr_running = rq->nr_running;
+		sgs->sum_nr_running += nr_running;
+
+		if (nr_running > 1)
+			*sg_status |= SG_OVERLOAD;
+
+		if (cpu_overutilized(i))
+			*sg_status |= SG_OVERUTILIZED;
+
+#ifdef CONFIG_NUMA_BALANCING
+		sgs->nr_numa_running += rq->nr_numa_running;
+		sgs->nr_preferred_running += rq->nr_preferred_running;
+#endif
+		/*
+		 * No need to call idle_cpu() if nr_running is not 0
+		 */
+		if (!nr_running && idle_cpu(i)) {
+			sgs->idle_cpus++;
+			/* Idle cpu can't have misfit task */
+			continue;
+		}
+
+		if (local_group)
+			continue;
+
+		if (env->sd->flags & SD_ASYM_CPUCAPACITY) {
+			/* Check for a misfit task on the cpu */
+			if (sgs->group_misfit_task_load < rq->misfit_task_load) {
+				sgs->group_misfit_task_load = rq->misfit_task_load;
+				*sg_status |= SG_OVERLOAD;
+			}
+		} else if ((env->idle != CPU_NOT_IDLE) &&
+			   sched_reduced_capacity(rq, env->sd)) {
+			/* Check for a task running on a CPU with reduced capacity */
+			if (sgs->group_misfit_task_load < load)
+				sgs->group_misfit_task_load = load;
+		}
+	}
+
+	sgs->group_capacity = group->sgc->capacity;
+
+	sgs->group_weight = group->group_weight;
+
+	/* Check if dst CPU is idle and preferred to this group */
+	if (!local_group && env->sd->flags & SD_ASYM_PACKING &&
+	    env->idle != CPU_NOT_IDLE && sgs->sum_h_nr_running &&
+	    sched_asym(env, sds, sgs, group)) {
+		sgs->group_asym_packing = 1;
+	}
+
+	sgs->group_type = group_classify(env->sd->imbalance_pct, group, sgs);
+
+	/* Computing avg_load makes sense only when group is overloaded */
+	if (sgs->group_type == group_overloaded)
+		sgs->avg_load = (sgs->group_load * SCHED_CAPACITY_SCALE) /
+				sgs->group_capacity;
+}
+
+/**
+ * update_sd_pick_busiest - return 1 on busiest group
+ * @env: The load balancing environment.
+ * @sds: sched_domain statistics
+ * @sg: sched_group candidate to be checked for being the busiest
+ * @sgs: sched_group statistics
+ *
+ * Determine if @sg is a busier group than the previously selected
+ * busiest group.
+ *
+ * Return: %true if @sg is a busier group than the previously selected
+ * busiest group. %false otherwise.
+ */
+static bool update_sd_pick_busiest(struct lb_env *env,
+				   struct sd_lb_stats *sds,
+				   struct sched_group *sg,
+				   struct sg_lb_stats *sgs)
+{
+	struct sg_lb_stats *busiest = &sds->busiest_stat;
+
+	/* Make sure that there is at least one task to pull */
+	if (!sgs->sum_h_nr_running)
+		return false;
+
+	/*
+	 * Don't try to pull misfit tasks we can't help.
+	 * We can use max_capacity here as reduction in capacity on some
+	 * CPUs in the group should either be possible to resolve
+	 * internally or be covered by avg_load imbalance (eventually).
+	 */
+	if ((env->sd->flags & SD_ASYM_CPUCAPACITY) &&
+	    (sgs->group_type == group_misfit_task) &&
+	    (!capacity_greater(capacity_of(env->dst_cpu), sg->sgc->max_capacity) ||
+	     sds->local_stat.group_type != group_has_spare))
+		return false;
+
+	if (sgs->group_type > busiest->group_type)
+		return true;
+
+	if (sgs->group_type < busiest->group_type)
+		return false;
+
+	/*
+	 * The candidate and the current busiest group are the same type of
+	 * group. Let check which one is the busiest according to the type.
+	 */
+
+	switch (sgs->group_type) {
+	case group_overloaded:
+		/* Select the overloaded group with highest avg_load. */
+		if (sgs->avg_load <= busiest->avg_load)
+			return false;
+		break;
+
+	case group_imbalanced:
+		/*
+		 * Select the 1st imbalanced group as we don't have any way to
+		 * choose one more than another.
+		 */
+		return false;
+
+	case group_asym_packing:
+		/* Prefer to move from lowest priority CPU's work */
+		if (sched_asym_prefer(sg->asym_prefer_cpu, sds->busiest->asym_prefer_cpu))
+			return false;
+		break;
+
+	case group_misfit_task:
+		/*
+		 * If we have more than one misfit sg go with the biggest
+		 * misfit.
+		 */
+		if (sgs->group_misfit_task_load < busiest->group_misfit_task_load)
+			return false;
+		break;
+
+	case group_fully_busy:
+		/*
+		 * Select the fully busy group with highest avg_load. In
+		 * theory, there is no need to pull task from such kind of
+		 * group because tasks have all compute capacity that they need
+		 * but we can still improve the overall throughput by reducing
+		 * contention when accessing shared HW resources.
+		 *
+		 * XXX for now avg_load is not computed and always 0 so we
+		 * select the 1st one.
+		 */
+		if (sgs->avg_load <= busiest->avg_load)
+			return false;
+		break;
+
+	case group_has_spare:
+		/*
+		 * Select not overloaded group with lowest number of idle cpus
+		 * and highest number of running tasks. We could also compare
+		 * the spare capacity which is more stable but it can end up
+		 * that the group has less spare capacity but finally more idle
+		 * CPUs which means less opportunity to pull tasks.
+		 */
+		if (sgs->idle_cpus > busiest->idle_cpus)
+			return false;
+		else if ((sgs->idle_cpus == busiest->idle_cpus) &&
+			 (sgs->sum_nr_running <= busiest->sum_nr_running))
+			return false;
+
+		break;
+	}
+
+	/*
+	 * Candidate sg has no more than one task per CPU and has higher
+	 * per-CPU capacity. Migrating tasks to less capable CPUs may harm
+	 * throughput. Maximize throughput, power/energy consequences are not
+	 * considered.
+	 */
+	if ((env->sd->flags & SD_ASYM_CPUCAPACITY) &&
+	    (sgs->group_type <= group_fully_busy) &&
+	    (capacity_greater(sg->sgc->min_capacity, capacity_of(env->dst_cpu))))
+		return false;
+
+	return true;
+}
+
+#ifdef CONFIG_NUMA_BALANCING
+static inline enum fbq_type fbq_classify_group(struct sg_lb_stats *sgs)
+{
+	if (sgs->sum_h_nr_running > sgs->nr_numa_running)
+		return regular;
+	if (sgs->sum_h_nr_running > sgs->nr_preferred_running)
+		return remote;
+	return all;
+}
+
+static inline enum fbq_type fbq_classify_rq(struct rq *rq)
+{
+	if (rq->nr_running > rq->nr_numa_running)
+		return regular;
+	if (rq->nr_running > rq->nr_preferred_running)
+		return remote;
+	return all;
+}
+#else
+static inline enum fbq_type fbq_classify_group(struct sg_lb_stats *sgs)
+{
+	return all;
+}
+
+static inline enum fbq_type fbq_classify_rq(struct rq *rq)
+{
+	return regular;
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
+
+struct sg_lb_stats;
+
+/*
+ * task_running_on_cpu - return 1 if @p is running on @cpu.
+ */
+
+static unsigned int task_running_on_cpu(int cpu, struct task_struct *p)
+{
+	/* Task has no contribution or is new */
+	if (cpu != task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time))
+		return 0;
+
+	if (task_on_rq_queued(p))
+		return 1;
+
+	return 0;
+}
+
+/**
+ * idle_cpu_without - would a given CPU be idle without p ?
+ * @cpu: the processor on which idleness is tested.
+ * @p: task which should be ignored.
+ *
+ * Return: 1 if the CPU would be idle. 0 otherwise.
+ */
+static int idle_cpu_without(int cpu, struct task_struct *p)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (rq->curr != rq->idle && rq->curr != p)
+		return 0;
+
+	/*
+	 * rq->nr_running can't be used but an updated version without the
+	 * impact of p on cpu must be used instead. The updated nr_running
+	 * be computed and tested before calling idle_cpu_without().
+	 */
+
+#ifdef CONFIG_SMP
+	if (rq->ttwu_pending)
+		return 0;
+#endif
+
+	return 1;
+}
+
+/*
+ * update_sg_wakeup_stats - Update sched_group's statistics for wakeup.
+ * @sd: The sched_domain level to look for idlest group.
+ * @group: sched_group whose statistics are to be updated.
+ * @sgs: variable to hold the statistics for this group.
+ * @p: The task for which we look for the idlest group/CPU.
+ */
+static inline void update_sg_wakeup_stats(struct sched_domain *sd,
+					  struct sched_group *group,
+					  struct sg_lb_stats *sgs,
+					  struct task_struct *p)
+{
+	int i, nr_running;
+
+	memset(sgs, 0, sizeof(*sgs));
+
+	/* Assume that task can't fit any CPU of the group */
+	if (sd->flags & SD_ASYM_CPUCAPACITY)
+		sgs->group_misfit_task_load = 1;
+
+	for_each_cpu(i, sched_group_span(group)) {
+		struct rq *rq = cpu_rq(i);
+		unsigned int local;
+
+		sgs->group_load += cpu_load_without(rq, p);
+		sgs->group_util += cpu_util_without(i, p);
+		sgs->group_runnable += cpu_runnable_without(rq, p);
+		local = task_running_on_cpu(i, p);
+		sgs->sum_h_nr_running += rq->cfs.h_nr_running - local;
+
+		nr_running = rq->nr_running - local;
+		sgs->sum_nr_running += nr_running;
+
+		/*
+		 * No need to call idle_cpu_without() if nr_running is not 0
+		 */
+		if (!nr_running && idle_cpu_without(i, p))
+			sgs->idle_cpus++;
+
+		/* Check if task fits in the CPU */
+		if (sd->flags & SD_ASYM_CPUCAPACITY &&
+		    sgs->group_misfit_task_load &&
+		    task_fits_cpu(p, i))
+			sgs->group_misfit_task_load = 0;
+
+	}
+
+	sgs->group_capacity = group->sgc->capacity;
+
+	sgs->group_weight = group->group_weight;
+
+	sgs->group_type = group_classify(sd->imbalance_pct, group, sgs);
+
+	/*
+	 * Computing avg_load makes sense only when group is fully busy or
+	 * overloaded
+	 */
+	if (sgs->group_type == group_fully_busy ||
+		sgs->group_type == group_overloaded)
+		sgs->avg_load = (sgs->group_load * SCHED_CAPACITY_SCALE) /
+				sgs->group_capacity;
+}
+
+static bool update_pick_idlest(struct sched_group *idlest,
+			       struct sg_lb_stats *idlest_sgs,
+			       struct sched_group *group,
+			       struct sg_lb_stats *sgs)
+{
+	if (sgs->group_type < idlest_sgs->group_type)
+		return true;
+
+	if (sgs->group_type > idlest_sgs->group_type)
+		return false;
+
+	/*
+	 * The candidate and the current idlest group are the same type of
+	 * group. Let check which one is the idlest according to the type.
+	 */
+
+	switch (sgs->group_type) {
+	case group_overloaded:
+	case group_fully_busy:
+		/* Select the group with lowest avg_load. */
+		if (idlest_sgs->avg_load <= sgs->avg_load)
+			return false;
+		break;
+
+	case group_imbalanced:
+	case group_asym_packing:
+		/* Those types are not used in the slow wakeup path */
+		return false;
+
+	case group_misfit_task:
+		/* Select group with the highest max capacity */
+		if (idlest->sgc->max_capacity >= group->sgc->max_capacity)
+			return false;
+		break;
+
+	case group_has_spare:
+		/* Select group with most idle CPUs */
+		if (idlest_sgs->idle_cpus > sgs->idle_cpus)
+			return false;
+
+		/* Select group with lowest group_util */
+		if (idlest_sgs->idle_cpus == sgs->idle_cpus &&
+			idlest_sgs->group_util <= sgs->group_util)
+			return false;
+
+		break;
+	}
+
+	return true;
+}
+
+/*
+ * find_idlest_group() finds and returns the least busy CPU group within the
+ * domain.
+ *
+ * Assumes p is allowed on at least one CPU in sd.
+ */
+static struct sched_group *
+find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
+{
+	struct sched_group *idlest = NULL, *local = NULL, *group = sd->groups;
+	struct sg_lb_stats local_sgs, tmp_sgs;
+	struct sg_lb_stats *sgs;
+	unsigned long imbalance;
+	struct sg_lb_stats idlest_sgs = {
+			.avg_load = UINT_MAX,
+			.group_type = group_overloaded,
+	};
+
+	do {
+		int local_group;
+
+		/* Skip over this group if it has no CPUs allowed */
+		if (!cpumask_intersects(sched_group_span(group),
+					p->cpus_ptr))
+			continue;
+
+		/* Skip over this group if no cookie matched */
+		if (!sched_group_cookie_match(cpu_rq(this_cpu), p, group))
+			continue;
+
+		local_group = cpumask_test_cpu(this_cpu,
+					       sched_group_span(group));
+
+		if (local_group) {
+			sgs = &local_sgs;
+			local = group;
+		} else {
+			sgs = &tmp_sgs;
+		}
+
+		update_sg_wakeup_stats(sd, group, sgs, p);
+
+		if (!local_group && update_pick_idlest(idlest, &idlest_sgs, group, sgs)) {
+			idlest = group;
+			idlest_sgs = *sgs;
+		}
+
+	} while (group = group->next, group != sd->groups);
+
+
+	/* There is no idlest group to push tasks to */
+	if (!idlest)
+		return NULL;
+
+	/* The local group has been skipped because of CPU affinity */
+	if (!local)
+		return idlest;
+
+	/*
+	 * If the local group is idler than the selected idlest group
+	 * don't try and push the task.
+	 */
+	if (local_sgs.group_type < idlest_sgs.group_type)
+		return NULL;
+
+	/*
+	 * If the local group is busier than the selected idlest group
+	 * try and push the task.
+	 */
+	if (local_sgs.group_type > idlest_sgs.group_type)
+		return idlest;
+
+	switch (local_sgs.group_type) {
+	case group_overloaded:
+	case group_fully_busy:
+
+		/* Calculate allowed imbalance based on load */
+		imbalance = scale_load_down(NICE_0_LOAD) *
+				(sd->imbalance_pct-100) / 100;
+
+		/*
+		 * When comparing groups across NUMA domains, it's possible for
+		 * the local domain to be very lightly loaded relative to the
+		 * remote domains but "imbalance" skews the comparison making
+		 * remote CPUs look much more favourable. When considering
+		 * cross-domain, add imbalance to the load on the remote node
+		 * and consider staying local.
+		 */
+
+		if ((sd->flags & SD_NUMA) &&
+		    ((idlest_sgs.avg_load + imbalance) >= local_sgs.avg_load))
+			return NULL;
+
+		/*
+		 * If the local group is less loaded than the selected
+		 * idlest group don't try and push any tasks.
+		 */
+		if (idlest_sgs.avg_load >= (local_sgs.avg_load + imbalance))
+			return NULL;
+
+		if (100 * local_sgs.avg_load <= sd->imbalance_pct * idlest_sgs.avg_load)
+			return NULL;
+		break;
+
+	case group_imbalanced:
+	case group_asym_packing:
+		/* Those type are not used in the slow wakeup path */
+		return NULL;
+
+	case group_misfit_task:
+		/* Select group with the highest max capacity */
+		if (local->sgc->max_capacity >= idlest->sgc->max_capacity)
+			return NULL;
+		break;
+
+	case group_has_spare:
+#ifdef CONFIG_NUMA
+		if (sd->flags & SD_NUMA) {
+			int imb_numa_nr = sd->imb_numa_nr;
+#ifdef CONFIG_NUMA_BALANCING
+			int idlest_cpu;
+			/*
+			 * If there is spare capacity at NUMA, try to select
+			 * the preferred node
+			 */
+			if (cpu_to_node(this_cpu) == p->numa_preferred_nid)
+				return NULL;
+
+			idlest_cpu = cpumask_first(sched_group_span(idlest));
+			if (cpu_to_node(idlest_cpu) == p->numa_preferred_nid)
+				return idlest;
+#endif /* CONFIG_NUMA_BALANCING */
+			/*
+			 * Otherwise, keep the task close to the wakeup source
+			 * and improve locality if the number of running tasks
+			 * would remain below threshold where an imbalance is
+			 * allowed while accounting for the possibility the
+			 * task is pinned to a subset of CPUs. If there is a
+			 * real need of migration, periodic load balance will
+			 * take care of it.
+			 */
+			if (p->nr_cpus_allowed != NR_CPUS) {
+				struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_rq_mask);
+
+				cpumask_and(cpus, sched_group_span(local), p->cpus_ptr);
+				imb_numa_nr = min(cpumask_weight(cpus), sd->imb_numa_nr);
+			}
+
+			imbalance = abs(local_sgs.idle_cpus - idlest_sgs.idle_cpus);
+			if (!adjust_numa_imbalance(imbalance,
+						   local_sgs.sum_nr_running + 1,
+						   imb_numa_nr)) {
+				return NULL;
+			}
+		}
+#endif /* CONFIG_NUMA */
+
+		/*
+		 * Select group with highest number of idle CPUs. We could also
+		 * compare the utilization which is more stable but it can end
+		 * up that the group has less spare capacity but finally more
+		 * idle CPUs which means more opportunity to run task.
+		 */
+		if (local_sgs.idle_cpus >= idlest_sgs.idle_cpus)
+			return NULL;
+		break;
+	}
+
+	return idlest;
+}
+
+static void update_idle_cpu_scan(struct lb_env *env,
+				 unsigned long sum_util)
+{
+	struct sched_domain_shared *sd_share;
+	int llc_weight, pct;
+	u64 x, y, tmp;
+	/*
+	 * Update the number of CPUs to scan in LLC domain, which could
+	 * be used as a hint in select_idle_cpu(). The update of sd_share
+	 * could be expensive because it is within a shared cache line.
+	 * So the write of this hint only occurs during periodic load
+	 * balancing, rather than CPU_NEWLY_IDLE, because the latter
+	 * can fire way more frequently than the former.
+	 */
+	if (!sched_feat(SIS_UTIL) || env->idle == CPU_NEWLY_IDLE)
+		return;
+
+	llc_weight = per_cpu(sd_llc_size, env->dst_cpu);
+	if (env->sd->span_weight != llc_weight)
+		return;
+
+	sd_share = rcu_dereference(per_cpu(sd_llc_shared, env->dst_cpu));
+	if (!sd_share)
+		return;
+
+	/*
+	 * The number of CPUs to search drops as sum_util increases, when
+	 * sum_util hits 85% or above, the scan stops.
+	 * The reason to choose 85% as the threshold is because this is the
+	 * imbalance_pct(117) when a LLC sched group is overloaded.
+	 *
+	 * let y = SCHED_CAPACITY_SCALE - p * x^2                       [1]
+	 * and y'= y / SCHED_CAPACITY_SCALE
+	 *
+	 * x is the ratio of sum_util compared to the CPU capacity:
+	 * x = sum_util / (llc_weight * SCHED_CAPACITY_SCALE)
+	 * y' is the ratio of CPUs to be scanned in the LLC domain,
+	 * and the number of CPUs to scan is calculated by:
+	 *
+	 * nr_scan = llc_weight * y'                                    [2]
+	 *
+	 * When x hits the threshold of overloaded, AKA, when
+	 * x = 100 / pct, y drops to 0. According to [1],
+	 * p should be SCHED_CAPACITY_SCALE * pct^2 / 10000
+	 *
+	 * Scale x by SCHED_CAPACITY_SCALE:
+	 * x' = sum_util / llc_weight;                                  [3]
+	 *
+	 * and finally [1] becomes:
+	 * y = SCHED_CAPACITY_SCALE -
+	 *     x'^2 * pct^2 / (10000 * SCHED_CAPACITY_SCALE)            [4]
+	 *
+	 */
+	/* equation [3] */
+	x = sum_util;
+	do_div(x, llc_weight);
+
+	/* equation [4] */
+	pct = env->sd->imbalance_pct;
+	tmp = x * x * pct * pct;
+	do_div(tmp, 10000 * SCHED_CAPACITY_SCALE);
+	tmp = min_t(long, tmp, SCHED_CAPACITY_SCALE);
+	y = SCHED_CAPACITY_SCALE - tmp;
+
+	/* equation [2] */
+	y *= llc_weight;
+	do_div(y, SCHED_CAPACITY_SCALE);
+	if ((int)y != sd_share->nr_idle_scan)
+		WRITE_ONCE(sd_share->nr_idle_scan, (int)y);
+}
+
+/**
+ * update_sd_lb_stats - Update sched_domain's statistics for load balancing.
+ * @env: The load balancing environment.
+ * @sds: variable to hold the statistics for this sched_domain.
+ */
+
+static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sds)
+{
+	struct sched_domain *child = env->sd->child;
+	struct sched_group *sg = env->sd->groups;
+	struct sg_lb_stats *local = &sds->local_stat;
+	struct sg_lb_stats tmp_sgs;
+	unsigned long sum_util = 0;
+	int sg_status = 0;
+
+	do {
+		struct sg_lb_stats *sgs = &tmp_sgs;
+		int local_group;
+
+		local_group = cpumask_test_cpu(env->dst_cpu, sched_group_span(sg));
+		if (local_group) {
+			sds->local = sg;
+			sgs = local;
+
+			if (env->idle != CPU_NEWLY_IDLE ||
+			    time_after_eq(jiffies, sg->sgc->next_update))
+				update_group_capacity(env->sd, env->dst_cpu);
+		}
+
+		update_sg_lb_stats(env, sds, sg, sgs, &sg_status);
+
+		if (local_group)
+			goto next_group;
+
+
+		if (update_sd_pick_busiest(env, sds, sg, sgs)) {
+			sds->busiest = sg;
+			sds->busiest_stat = *sgs;
+		}
+
+next_group:
+		/* Now, start updating sd_lb_stats */
+		sds->total_load += sgs->group_load;
+		sds->total_capacity += sgs->group_capacity;
+
+		sum_util += sgs->group_util;
+		sg = sg->next;
+	} while (sg != env->sd->groups);
+
+	/* Tag domain that child domain prefers tasks go to siblings first */
+	sds->prefer_sibling = child && child->flags & SD_PREFER_SIBLING;
+
+
+	if (env->sd->flags & SD_NUMA)
+		env->fbq_type = fbq_classify_group(&sds->busiest_stat);
+
+	if (!env->sd->parent) {
+		struct root_domain *rd = env->dst_rq->rd;
+
+		/* update overload indicator if we are at root domain */
+		WRITE_ONCE(rd->overload, sg_status & SG_OVERLOAD);
+
+		/* Update over-utilization (tipping point, U >= 0) indicator */
+		WRITE_ONCE(rd->overutilized, sg_status & SG_OVERUTILIZED);
+		trace_sched_overutilized_tp(rd, sg_status & SG_OVERUTILIZED);
+	} else if (sg_status & SG_OVERUTILIZED) {
+		struct root_domain *rd = env->dst_rq->rd;
+
+		WRITE_ONCE(rd->overutilized, SG_OVERUTILIZED);
+		trace_sched_overutilized_tp(rd, SG_OVERUTILIZED);
+	}
+
+	update_idle_cpu_scan(env, sum_util);
+}
+
+/**
+ * calculate_imbalance - Calculate the amount of imbalance present within the
+ *			 groups of a given sched_domain during load balance.
+ * @env: load balance environment
+ * @sds: statistics of the sched_domain whose imbalance is to be calculated.
+ */
+static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *sds)
+{
+	struct sg_lb_stats *local, *busiest;
+
+	local = &sds->local_stat;
+	busiest = &sds->busiest_stat;
+
+	if (busiest->group_type == group_misfit_task) {
+		if (env->sd->flags & SD_ASYM_CPUCAPACITY) {
+			/* Set imbalance to allow misfit tasks to be balanced. */
+			env->migration_type = migrate_misfit;
+			env->imbalance = 1;
+		} else {
+			/*
+			 * Set load imbalance to allow moving task from cpu
+			 * with reduced capacity.
+			 */
+			env->migration_type = migrate_load;
+			env->imbalance = busiest->group_misfit_task_load;
+		}
+		return;
+	}
+
+	if (busiest->group_type == group_asym_packing) {
+		/*
+		 * In case of asym capacity, we will try to migrate all load to
+		 * the preferred CPU.
+		 */
+		env->migration_type = migrate_task;
+		env->imbalance = busiest->sum_h_nr_running;
+		return;
+	}
+
+	if (busiest->group_type == group_imbalanced) {
+		/*
+		 * In the group_imb case we cannot rely on group-wide averages
+		 * to ensure CPU-load equilibrium, try to move any task to fix
+		 * the imbalance. The next load balance will take care of
+		 * balancing back the system.
+		 */
+		env->migration_type = migrate_task;
+		env->imbalance = 1;
+		return;
+	}
+
+	/*
+	 * Try to use spare capacity of local group without overloading it or
+	 * emptying busiest.
+	 */
+	if (local->group_type == group_has_spare) {
+		if ((busiest->group_type > group_fully_busy) &&
+		    !(env->sd->flags & SD_SHARE_PKG_RESOURCES)) {
+			/*
+			 * If busiest is overloaded, try to fill spare
+			 * capacity. This might end up creating spare capacity
+			 * in busiest or busiest still being overloaded but
+			 * there is no simple way to directly compute the
+			 * amount of load to migrate in order to balance the
+			 * system.
+			 */
+			env->migration_type = migrate_util;
+			env->imbalance = max(local->group_capacity, local->group_util) -
+					 local->group_util;
+
+			/*
+			 * In some cases, the group's utilization is max or even
+			 * higher than capacity because of migrations but the
+			 * local CPU is (newly) idle. There is at least one
+			 * waiting task in this overloaded busiest group. Let's
+			 * try to pull it.
+			 */
+			if (env->idle != CPU_NOT_IDLE && env->imbalance == 0) {
+				env->migration_type = migrate_task;
+				env->imbalance = 1;
+			}
+
+			return;
+		}
+
+		if (busiest->group_weight == 1 || sds->prefer_sibling) {
+			unsigned int nr_diff = busiest->sum_nr_running;
+			/*
+			 * When prefer sibling, evenly spread running tasks on
+			 * groups.
+			 */
+			env->migration_type = migrate_task;
+			lsub_positive(&nr_diff, local->sum_nr_running);
+			env->imbalance = nr_diff;
+		} else {
+
+			/*
+			 * If there is no overload, we just want to even the number of
+			 * idle cpus.
+			 */
+			env->migration_type = migrate_task;
+			env->imbalance = max_t(long, 0,
+					       (local->idle_cpus - busiest->idle_cpus));
+		}
+
+#ifdef CONFIG_NUMA
+		/* Consider allowing a small imbalance between NUMA groups */
+		if (env->sd->flags & SD_NUMA) {
+			env->imbalance = adjust_numa_imbalance(env->imbalance,
+							       local->sum_nr_running + 1,
+							       env->sd->imb_numa_nr);
+		}
+#endif
+
+		/* Number of tasks to move to restore balance */
+		env->imbalance >>= 1;
+
+		return;
+	}
+
+	/*
+	 * Local is fully busy but has to take more load to relieve the
+	 * busiest group
+	 */
+	if (local->group_type < group_overloaded) {
+		/*
+		 * Local will become overloaded so the avg_load metrics are
+		 * finally needed.
+		 */
+
+		local->avg_load = (local->group_load * SCHED_CAPACITY_SCALE) /
+				  local->group_capacity;
+
+		/*
+		 * If the local group is more loaded than the selected
+		 * busiest group don't try to pull any tasks.
+		 */
+		if (local->avg_load >= busiest->avg_load) {
+			env->imbalance = 0;
+			return;
+		}
+
+		sds->avg_load = (sds->total_load * SCHED_CAPACITY_SCALE) /
+				sds->total_capacity;
+
+		/*
+		 * If the local group is more loaded than the average system
+		 * load, don't try to pull any tasks.
+		 */
+		if (local->avg_load >= sds->avg_load) {
+			env->imbalance = 0;
+			return;
+		}
+
+	}
+
+	/*
+	 * Both group are or will become overloaded and we're trying to get all
+	 * the CPUs to the average_load, so we don't want to push ourselves
+	 * above the average load, nor do we wish to reduce the max loaded CPU
+	 * below the average load. At the same time, we also don't want to
+	 * reduce the group load below the group capacity. Thus we look for
+	 * the minimum possible imbalance.
+	 */
+	env->migration_type = migrate_load;
+	env->imbalance = min(
+		(busiest->avg_load - sds->avg_load) * busiest->group_capacity,
+		(sds->avg_load - local->avg_load) * local->group_capacity
+	) / SCHED_CAPACITY_SCALE;
+}
+
+/******* find_busiest_group() helpers end here *********************/
+
+/*
+ * Decision matrix according to the local and busiest group type:
+ *
+ * busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
+ * has_spare        nr_idle   balanced   N/A    N/A  balanced   balanced
+ * fully_busy       nr_idle   nr_idle    N/A    N/A  balanced   balanced
+ * misfit_task      force     N/A        N/A    N/A  N/A        N/A
+ * asym_packing     force     force      N/A    N/A  force      force
+ * imbalanced       force     force      N/A    N/A  force      force
+ * overloaded       force     force      N/A    N/A  force      avg_load
+ *
+ * N/A :      Not Applicable because already filtered while updating
+ *            statistics.
+ * balanced : The system is balanced for these 2 groups.
+ * force :    Calculate the imbalance as load migration is probably needed.
+ * avg_load : Only if imbalance is significant enough.
+ * nr_idle :  dst_cpu is not busy and the number of idle CPUs is quite
+ *            different in groups.
+ */
+
+/**
+ * find_busiest_group - Returns the busiest group within the sched_domain
+ * if there is an imbalance.
+ * @env: The load balancing environment.
+ *
+ * Also calculates the amount of runnable load which should be moved
+ * to restore balance.
+ *
+ * Return:	- The busiest group if imbalance exists.
+ */
+static struct sched_group *find_busiest_group(struct lb_env *env)
+{
+	struct sg_lb_stats *local, *busiest;
+	struct sd_lb_stats sds;
+
+	init_sd_lb_stats(&sds);
+
+	/*
+	 * Compute the various statistics relevant for load balancing at
+	 * this level.
+	 */
+	update_sd_lb_stats(env, &sds);
+
+	/* There is no busy sibling group to pull tasks from */
+	if (!sds.busiest)
+		goto out_balanced;
+
+	busiest = &sds.busiest_stat;
+
+	/* Misfit tasks should be dealt with regardless of the avg load */
+	if (busiest->group_type == group_misfit_task)
+		goto force_balance;
+
+	if (sched_energy_enabled()) {
+		struct root_domain *rd = env->dst_rq->rd;
+
+		if (rcu_dereference(rd->pd) && !READ_ONCE(rd->overutilized))
+			goto out_balanced;
+	}
+
+	/* ASYM feature bypasses nice load balance check */
+	if (busiest->group_type == group_asym_packing)
+		goto force_balance;
+
+	/*
+	 * If the busiest group is imbalanced the below checks don't
+	 * work because they assume all things are equal, which typically
+	 * isn't true due to cpus_ptr constraints and the like.
+	 */
+	if (busiest->group_type == group_imbalanced)
+		goto force_balance;
+
+	local = &sds.local_stat;
+	/*
+	 * If the local group is busier than the selected busiest group
+	 * don't try and pull any tasks.
+	 */
+	if (local->group_type > busiest->group_type)
+		goto out_balanced;
+
+	/*
+	 * When groups are overloaded, use the avg_load to ensure fairness
+	 * between tasks.
+	 */
+	if (local->group_type == group_overloaded) {
+		/*
+		 * If the local group is more loaded than the selected
+		 * busiest group don't try to pull any tasks.
+		 */
+		if (local->avg_load >= busiest->avg_load)
+			goto out_balanced;
+
+		/* XXX broken for overlapping NUMA groups */
+		sds.avg_load = (sds.total_load * SCHED_CAPACITY_SCALE) /
+				sds.total_capacity;
+
+		/*
+		 * Don't pull any tasks if this group is already above the
+		 * domain average load.
+		 */
+		if (local->avg_load >= sds.avg_load)
+			goto out_balanced;
+
+		/*
+		 * If the busiest group is more loaded, use imbalance_pct to be
+		 * conservative.
+		 */
+		if (100 * busiest->avg_load <=
+				env->sd->imbalance_pct * local->avg_load)
+			goto out_balanced;
+	}
+
+	/* Try to move all excess tasks to child's sibling domain */
+	if (sds.prefer_sibling && local->group_type == group_has_spare &&
+	    busiest->sum_nr_running > local->sum_nr_running + 1)
+		goto force_balance;
+
+	if (busiest->group_type != group_overloaded) {
+		if (env->idle == CPU_NOT_IDLE)
+			/*
+			 * If the busiest group is not overloaded (and as a
+			 * result the local one too) but this CPU is already
+			 * busy, let another idle CPU try to pull task.
+			 */
+			goto out_balanced;
+
+		if (busiest->group_weight > 1 &&
+		    local->idle_cpus <= (busiest->idle_cpus + 1))
+			/*
+			 * If the busiest group is not overloaded
+			 * and there is no imbalance between this and busiest
+			 * group wrt idle CPUs, it is balanced. The imbalance
+			 * becomes significant if the diff is greater than 1
+			 * otherwise we might end up to just move the imbalance
+			 * on another group. Of course this applies only if
+			 * there is more than 1 CPU per group.
+			 */
+			goto out_balanced;
+
+		if (busiest->sum_h_nr_running == 1)
+			/*
+			 * busiest doesn't have any tasks waiting to run
+			 */
+			goto out_balanced;
+	}
+
+force_balance:
+	/* Looks like there is an imbalance. Compute it */
+	calculate_imbalance(env, &sds);
+	return env->imbalance ? sds.busiest : NULL;
+
+out_balanced:
+	env->imbalance = 0;
+	return NULL;
+}
+
+/*
+ * find_busiest_queue - find the busiest runqueue among the CPUs in the group.
+ */
+static struct rq *find_busiest_queue(struct lb_env *env,
+				     struct sched_group *group)
+{
+	struct rq *busiest = NULL, *rq;
+	unsigned long busiest_util = 0, busiest_load = 0, busiest_capacity = 1;
+	unsigned int busiest_nr = 0;
+	int i;
+
+	for_each_cpu_and(i, sched_group_span(group), env->cpus) {
+		unsigned long capacity, load, util;
+		unsigned int nr_running;
+		enum fbq_type rt;
+
+		rq = cpu_rq(i);
+		rt = fbq_classify_rq(rq);
+
+		/*
+		 * We classify groups/runqueues into three groups:
+		 *  - regular: there are !numa tasks
+		 *  - remote:  there are numa tasks that run on the 'wrong' node
+		 *  - all:     there is no distinction
+		 *
+		 * In order to avoid migrating ideally placed numa tasks,
+		 * ignore those when there's better options.
+		 *
+		 * If we ignore the actual busiest queue to migrate another
+		 * task, the next balance pass can still reduce the busiest
+		 * queue by moving tasks around inside the node.
+		 *
+		 * If we cannot move enough load due to this classification
+		 * the next pass will adjust the group classification and
+		 * allow migration of more tasks.
+		 *
+		 * Both cases only affect the total convergence complexity.
+		 */
+		if (rt > env->fbq_type)
+			continue;
+
+		nr_running = rq->cfs.h_nr_running;
+		if (!nr_running)
+			continue;
+
+		capacity = capacity_of(i);
+
+		/*
+		 * For ASYM_CPUCAPACITY domains, don't pick a CPU that could
+		 * eventually lead to active_balancing high->low capacity.
+		 * Higher per-CPU capacity is considered better than balancing
+		 * average load.
+		 */
+		if (env->sd->flags & SD_ASYM_CPUCAPACITY &&
+		    !capacity_greater(capacity_of(env->dst_cpu), capacity) &&
+		    nr_running == 1)
+			continue;
+
+		/* Make sure we only pull tasks from a CPU of lower priority */
+		if ((env->sd->flags & SD_ASYM_PACKING) &&
+		    sched_asym_prefer(i, env->dst_cpu) &&
+		    nr_running == 1)
+			continue;
+
+		switch (env->migration_type) {
+		case migrate_load:
+			/*
+			 * When comparing with load imbalance, use cpu_load()
+			 * which is not scaled with the CPU capacity.
+			 */
+			load = cpu_load(rq);
+
+			if (nr_running == 1 && load > env->imbalance &&
+			    !check_cpu_capacity(rq, env->sd))
+				break;
+
+			/*
+			 * For the load comparisons with the other CPUs,
+			 * consider the cpu_load() scaled with the CPU
+			 * capacity, so that the load can be moved away
+			 * from the CPU that is potentially running at a
+			 * lower capacity.
+			 *
+			 * Thus we're looking for max(load_i / capacity_i),
+			 * crosswise multiplication to rid ourselves of the
+			 * division works out to:
+			 * load_i * capacity_j > load_j * capacity_i;
+			 * where j is our previous maximum.
+			 */
+			if (load * busiest_capacity > busiest_load * capacity) {
+				busiest_load = load;
+				busiest_capacity = capacity;
+				busiest = rq;
+			}
+			break;
+
+		case migrate_util:
+			util = cpu_util_cfs(i);
+
+			/*
+			 * Don't try to pull utilization from a CPU with one
+			 * running task. Whatever its utilization, we will fail
+			 * detach the task.
+			 */
+			if (nr_running <= 1)
+				continue;
+
+			if (busiest_util < util) {
+				busiest_util = util;
+				busiest = rq;
+			}
+			break;
+
+		case migrate_task:
+			if (busiest_nr < nr_running) {
+				busiest_nr = nr_running;
+				busiest = rq;
+			}
+			break;
+
+		case migrate_misfit:
+			/*
+			 * For ASYM_CPUCAPACITY domains with misfit tasks we
+			 * simply seek the "biggest" misfit task.
+			 */
+			if (rq->misfit_task_load > busiest_load) {
+				busiest_load = rq->misfit_task_load;
+				busiest = rq;
+			}
+
+			break;
+
+		}
+	}
+
+	return busiest;
+}
+
+/*
+ * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
+ * so long as it is large enough.
+ */
+#define MAX_PINNED_INTERVAL	512
+
+static inline bool
+asym_active_balance(struct lb_env *env)
+{
+	/*
+	 * ASYM_PACKING needs to force migrate tasks from busy but
+	 * lower priority CPUs in order to pack all tasks in the
+	 * highest priority CPUs.
+	 */
+	return env->idle != CPU_NOT_IDLE && (env->sd->flags & SD_ASYM_PACKING) &&
+	       sched_asym_prefer(env->dst_cpu, env->src_cpu);
+}
+
+static inline bool
+imbalanced_active_balance(struct lb_env *env)
+{
+	struct sched_domain *sd = env->sd;
+
+	/*
+	 * The imbalanced case includes the case of pinned tasks preventing a fair
+	 * distribution of the load on the system but also the even distribution of the
+	 * threads on a system with spare capacity
+	 */
+	if ((env->migration_type == migrate_task) &&
+	    (sd->nr_balance_failed > sd->cache_nice_tries+2))
+		return 1;
+
+	return 0;
+}
+
+static int need_active_balance(struct lb_env *env)
+{
+	struct sched_domain *sd = env->sd;
+
+	if (asym_active_balance(env))
+		return 1;
+
+	if (imbalanced_active_balance(env))
+		return 1;
+
+	/*
+	 * The dst_cpu is idle and the src_cpu CPU has only 1 CFS task.
+	 * It's worth migrating the task if the src_cpu's capacity is reduced
+	 * because of other sched_class or IRQs if more capacity stays
+	 * available on dst_cpu.
+	 */
+	if ((env->idle != CPU_NOT_IDLE) &&
+	    (env->src_rq->cfs.h_nr_running == 1)) {
+		if ((check_cpu_capacity(env->src_rq, sd)) &&
+		    (capacity_of(env->src_cpu)*sd->imbalance_pct < capacity_of(env->dst_cpu)*100))
+			return 1;
+	}
+
+	if (env->migration_type == migrate_misfit)
+		return 1;
+
+	return 0;
+}
+
+static int active_load_balance_cpu_stop(void *data);
+
+static int should_we_balance(struct lb_env *env)
+{
+	struct sched_group *sg = env->sd->groups;
+	int cpu;
+
+	/*
+	 * Ensure the balancing environment is consistent; can happen
+	 * when the softirq triggers 'during' hotplug.
+	 */
+	if (!cpumask_test_cpu(env->dst_cpu, env->cpus))
+		return 0;
+
+	/*
+	 * In the newly idle case, we will allow all the CPUs
+	 * to do the newly idle load balance.
+	 *
+	 * However, we bail out if we already have tasks or a wakeup pending,
+	 * to optimize wakeup latency.
+	 */
+	if (env->idle == CPU_NEWLY_IDLE) {
+		if (env->dst_rq->nr_running > 0 || env->dst_rq->ttwu_pending)
+			return 0;
+		return 1;
+	}
+
+	/* Try to find first idle CPU */
+	for_each_cpu_and(cpu, group_balance_mask(sg), env->cpus) {
+		if (!idle_cpu(cpu))
+			continue;
+
+		/* Are we the first idle CPU? */
+		return cpu == env->dst_cpu;
+	}
+
+	/* Are we the first CPU of this group ? */
+	return group_balance_cpu(sg) == env->dst_cpu;
+}
+
+/*
+ * Check this_cpu to ensure it is balanced within domain. Attempt to move
+ * tasks if there is an imbalance.
+ */
+static int load_balance(int this_cpu, struct rq *this_rq,
+			struct sched_domain *sd, enum cpu_idle_type idle,
+			int *continue_balancing)
+{
+	int ld_moved, cur_ld_moved, active_balance = 0;
+	struct sched_domain *sd_parent = sd->parent;
+	struct sched_group *group;
+	struct rq *busiest;
+	struct rq_flags rf;
+	struct cpumask *cpus = this_cpu_cpumask_var_ptr(load_balance_mask);
+	struct lb_env env = {
+		.sd		= sd,
+		.dst_cpu	= this_cpu,
+		.dst_rq		= this_rq,
+		.dst_grpmask    = group_balance_mask(sd->groups),
+		.idle		= idle,
+		.loop_break	= SCHED_NR_MIGRATE_BREAK,
+		.cpus		= cpus,
+		.fbq_type	= all,
+		.tasks		= LIST_HEAD_INIT(env.tasks),
+	};
+
+	cpumask_and(cpus, sched_domain_span(sd), cpu_active_mask);
+
+	schedstat_inc(sd->lb_count[idle]);
+
+redo:
+	if (!should_we_balance(&env)) {
+		*continue_balancing = 0;
+		goto out_balanced;
+	}
+
+	group = find_busiest_group(&env);
+	if (!group) {
+		schedstat_inc(sd->lb_nobusyg[idle]);
+		goto out_balanced;
+	}
+
+	busiest = find_busiest_queue(&env, group);
+	if (!busiest) {
+		schedstat_inc(sd->lb_nobusyq[idle]);
+		goto out_balanced;
+	}
+
+	WARN_ON_ONCE(busiest == env.dst_rq);
+
+	schedstat_add(sd->lb_imbalance[idle], env.imbalance);
+
+	env.src_cpu = busiest->cpu;
+	env.src_rq = busiest;
+
+	ld_moved = 0;
+	/* Clear this flag as soon as we find a pullable task */
+	env.flags |= LBF_ALL_PINNED;
+	if (busiest->nr_running > 1) {
+		/*
+		 * Attempt to move tasks. If find_busiest_group has found
+		 * an imbalance but busiest->nr_running <= 1, the group is
+		 * still unbalanced. ld_moved simply stays zero, so it is
+		 * correctly treated as an imbalance.
+		 */
+		env.loop_max  = min(sysctl_sched_nr_migrate, busiest->nr_running);
+
+more_balance:
+		rq_lock_irqsave(busiest, &rf);
+		update_rq_clock(busiest);
+
+		/*
+		 * cur_ld_moved - load moved in current iteration
+		 * ld_moved     - cumulative load moved across iterations
+		 */
+		cur_ld_moved = detach_tasks(&env);
+
+		/*
+		 * We've detached some tasks from busiest_rq. Every
+		 * task is masked "TASK_ON_RQ_MIGRATING", so we can safely
+		 * unlock busiest->lock, and we are able to be sure
+		 * that nobody can manipulate the tasks in parallel.
+		 * See task_rq_lock() family for the details.
+		 */
+
+		rq_unlock(busiest, &rf);
+
+		if (cur_ld_moved) {
+			attach_tasks(&env);
+			ld_moved += cur_ld_moved;
+		}
+
+		local_irq_restore(rf.flags);
+
+		if (env.flags & LBF_NEED_BREAK) {
+			env.flags &= ~LBF_NEED_BREAK;
+			/* Stop if we tried all running tasks */
+			if (env.loop < busiest->nr_running)
+				goto more_balance;
+		}
+
+		/*
+		 * Revisit (affine) tasks on src_cpu that couldn't be moved to
+		 * us and move them to an alternate dst_cpu in our sched_group
+		 * where they can run. The upper limit on how many times we
+		 * iterate on same src_cpu is dependent on number of CPUs in our
+		 * sched_group.
+		 *
+		 * This changes load balance semantics a bit on who can move
+		 * load to a given_cpu. In addition to the given_cpu itself
+		 * (or a ilb_cpu acting on its behalf where given_cpu is
+		 * nohz-idle), we now have balance_cpu in a position to move
+		 * load to given_cpu. In rare situations, this may cause
+		 * conflicts (balance_cpu and given_cpu/ilb_cpu deciding
+		 * _independently_ and at _same_ time to move some load to
+		 * given_cpu) causing excess load to be moved to given_cpu.
+		 * This however should not happen so much in practice and
+		 * moreover subsequent load balance cycles should correct the
+		 * excess load moved.
+		 */
+		if ((env.flags & LBF_DST_PINNED) && env.imbalance > 0) {
+
+			/* Prevent to re-select dst_cpu via env's CPUs */
+			__cpumask_clear_cpu(env.dst_cpu, env.cpus);
+
+			env.dst_rq	 = cpu_rq(env.new_dst_cpu);
+			env.dst_cpu	 = env.new_dst_cpu;
+			env.flags	&= ~LBF_DST_PINNED;
+			env.loop	 = 0;
+			env.loop_break	 = SCHED_NR_MIGRATE_BREAK;
+
+			/*
+			 * Go back to "more_balance" rather than "redo" since we
+			 * need to continue with same src_cpu.
+			 */
+			goto more_balance;
+		}
+
+		/*
+		 * We failed to reach balance because of affinity.
+		 */
+		if (sd_parent) {
+			int *group_imbalance = &sd_parent->groups->sgc->imbalance;
+
+			if ((env.flags & LBF_SOME_PINNED) && env.imbalance > 0)
+				*group_imbalance = 1;
+		}
+
+		/* All tasks on this runqueue were pinned by CPU affinity */
+		if (unlikely(env.flags & LBF_ALL_PINNED)) {
+			__cpumask_clear_cpu(cpu_of(busiest), cpus);
+			/*
+			 * Attempting to continue load balancing at the current
+			 * sched_domain level only makes sense if there are
+			 * active CPUs remaining as possible busiest CPUs to
+			 * pull load from which are not contained within the
+			 * destination group that is receiving any migrated
+			 * load.
+			 */
+			if (!cpumask_subset(cpus, env.dst_grpmask)) {
+				env.loop = 0;
+				env.loop_break = SCHED_NR_MIGRATE_BREAK;
+				goto redo;
+			}
+			goto out_all_pinned;
+		}
+	}
+
+	if (!ld_moved) {
+		schedstat_inc(sd->lb_failed[idle]);
+		/*
+		 * Increment the failure counter only on periodic balance.
+		 * We do not want newidle balance, which can be very
+		 * frequent, pollute the failure counter causing
+		 * excessive cache_hot migrations and active balances.
+		 */
+		if (idle != CPU_NEWLY_IDLE)
+			sd->nr_balance_failed++;
+
+		if (need_active_balance(&env)) {
+			unsigned long flags;
+
+			raw_spin_rq_lock_irqsave(busiest, flags);
+
+			/*
+			 * Don't kick the active_load_balance_cpu_stop,
+			 * if the curr task on busiest CPU can't be
+			 * moved to this_cpu:
+			 */
+			if (!cpumask_test_cpu(this_cpu, busiest->curr->cpus_ptr)) {
+				raw_spin_rq_unlock_irqrestore(busiest, flags);
+				goto out_one_pinned;
+			}
+
+			/* Record that we found at least one task that could run on this_cpu */
+			env.flags &= ~LBF_ALL_PINNED;
+
+			/*
+			 * ->active_balance synchronizes accesses to
+			 * ->active_balance_work.  Once set, it's cleared
+			 * only after active load balance is finished.
+			 */
+			if (!busiest->active_balance) {
+				busiest->active_balance = 1;
+				busiest->push_cpu = this_cpu;
+				active_balance = 1;
+			}
+
+			preempt_disable();
+			raw_spin_rq_unlock_irqrestore(busiest, flags);
+			if (active_balance) {
+				stop_one_cpu_nowait(cpu_of(busiest),
+					active_load_balance_cpu_stop, busiest,
+					&busiest->active_balance_work);
+			}
+			preempt_enable();
+		}
+	} else {
+		sd->nr_balance_failed = 0;
+	}
+
+	if (likely(!active_balance) || need_active_balance(&env)) {
+		/* We were unbalanced, so reset the balancing interval */
+		sd->balance_interval = sd->min_interval;
+	}
+
+	goto out;
+
+out_balanced:
+	/*
+	 * We reach balance although we may have faced some affinity
+	 * constraints. Clear the imbalance flag only if other tasks got
+	 * a chance to move and fix the imbalance.
+	 */
+	if (sd_parent && !(env.flags & LBF_ALL_PINNED)) {
+		int *group_imbalance = &sd_parent->groups->sgc->imbalance;
+
+		if (*group_imbalance)
+			*group_imbalance = 0;
+	}
+
+out_all_pinned:
+	/*
+	 * We reach balance because all tasks are pinned at this level so
+	 * we can't migrate them. Let the imbalance flag set so parent level
+	 * can try to migrate them.
+	 */
+	schedstat_inc(sd->lb_balanced[idle]);
+
+	sd->nr_balance_failed = 0;
+
+out_one_pinned:
+	ld_moved = 0;
+
+	/*
+	 * newidle_balance() disregards balance intervals, so we could
+	 * repeatedly reach this code, which would lead to balance_interval
+	 * skyrocketing in a short amount of time. Skip the balance_interval
+	 * increase logic to avoid that.
+	 */
+	if (env.idle == CPU_NEWLY_IDLE)
+		goto out;
+
+	/* tune up the balancing interval */
+	if ((env.flags & LBF_ALL_PINNED &&
+	     sd->balance_interval < MAX_PINNED_INTERVAL) ||
+	    sd->balance_interval < sd->max_interval)
+		sd->balance_interval *= 2;
+out:
+	return ld_moved;
+}
+
+static inline unsigned long
+get_sd_balance_interval(struct sched_domain *sd, int cpu_busy)
+{
+	unsigned long interval = sd->balance_interval;
+
+	if (cpu_busy)
+		interval *= sd->busy_factor;
+
+	/* scale ms to jiffies */
+	interval = msecs_to_jiffies(interval);
+
+	/*
+	 * Reduce likelihood of busy balancing at higher domains racing with
+	 * balancing at lower domains by preventing their balancing periods
+	 * from being multiples of each other.
+	 */
+	if (cpu_busy)
+		interval -= 1;
+
+	interval = clamp(interval, 1UL, max_load_balance_interval);
+
+	return interval;
+}
+
+static inline void
+update_next_balance(struct sched_domain *sd, unsigned long *next_balance)
+{
+	unsigned long interval, next;
+
+	/* used by idle balance, so cpu_busy = 0 */
+	interval = get_sd_balance_interval(sd, 0);
+	next = sd->last_balance + interval;
+
+	if (time_after(*next_balance, next))
+		*next_balance = next;
+}
+
+/*
+ * active_load_balance_cpu_stop is run by the CPU stopper. It pushes
+ * running tasks off the busiest CPU onto idle CPUs. It requires at
+ * least 1 task to be running on each physical CPU where possible, and
+ * avoids physical / logical imbalances.
+ */
+static int active_load_balance_cpu_stop(void *data)
+{
+	struct rq *busiest_rq = data;
+	int busiest_cpu = cpu_of(busiest_rq);
+	int target_cpu = busiest_rq->push_cpu;
+	struct rq *target_rq = cpu_rq(target_cpu);
+	struct sched_domain *sd;
+	struct task_struct *p = NULL;
+	struct rq_flags rf;
+
+	rq_lock_irq(busiest_rq, &rf);
+	/*
+	 * Between queueing the stop-work and running it is a hole in which
+	 * CPUs can become inactive. We should not move tasks from or to
+	 * inactive CPUs.
+	 */
+	if (!cpu_active(busiest_cpu) || !cpu_active(target_cpu))
+		goto out_unlock;
+
+	/* Make sure the requested CPU hasn't gone down in the meantime: */
+	if (unlikely(busiest_cpu != smp_processor_id() ||
+		     !busiest_rq->active_balance))
+		goto out_unlock;
+
+	/* Is there any task to move? */
+	if (busiest_rq->nr_running <= 1)
+		goto out_unlock;
+
+	/*
+	 * This condition is "impossible", if it occurs
+	 * we need to fix it. Originally reported by
+	 * Bjorn Helgaas on a 128-CPU setup.
+	 */
+	WARN_ON_ONCE(busiest_rq == target_rq);
+
+	/* Search for an sd spanning us and the target CPU. */
+	rcu_read_lock();
+	for_each_domain(target_cpu, sd) {
+		if (cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
+			break;
+	}
+
+	if (likely(sd)) {
+		struct lb_env env = {
+			.sd		= sd,
+			.dst_cpu	= target_cpu,
+			.dst_rq		= target_rq,
+			.src_cpu	= busiest_rq->cpu,
+			.src_rq		= busiest_rq,
+			.idle		= CPU_IDLE,
+			.flags		= LBF_ACTIVE_LB,
+		};
+
+		schedstat_inc(sd->alb_count);
+		update_rq_clock(busiest_rq);
+
+		p = detach_one_task(&env);
+		if (p) {
+			schedstat_inc(sd->alb_pushed);
+			/* Active balancing done, reset the failure counter. */
+			sd->nr_balance_failed = 0;
+		} else {
+			schedstat_inc(sd->alb_failed);
+		}
+	}
+	rcu_read_unlock();
+out_unlock:
+	busiest_rq->active_balance = 0;
+	rq_unlock(busiest_rq, &rf);
+
+	if (p)
+		attach_one_task(target_rq, p);
+
+	local_irq_enable();
+
+	return 0;
+}
+
+static DEFINE_SPINLOCK(balancing);
+
+/*
+ * Scale the max load_balance interval with the number of CPUs in the system.
+ * This trades load-balance latency on larger machines for less cross talk.
+ */
+void update_max_interval(void)
+{
+	max_load_balance_interval = HZ*num_online_cpus()/10;
+}
+
+static inline bool update_newidle_cost(struct sched_domain *sd, u64 cost)
+{
+	if (cost > sd->max_newidle_lb_cost) {
+		/*
+		 * Track max cost of a domain to make sure to not delay the
+		 * next wakeup on the CPU.
+		 */
+		sd->max_newidle_lb_cost = cost;
+		sd->last_decay_max_lb_cost = jiffies;
+	} else if (time_after(jiffies, sd->last_decay_max_lb_cost + HZ)) {
+		/*
+		 * Decay the newidle max times by ~1% per second to ensure that
+		 * it is not outdated and the current max cost is actually
+		 * shorter.
+		 */
+		sd->max_newidle_lb_cost = (sd->max_newidle_lb_cost * 253) / 256;
+		sd->last_decay_max_lb_cost = jiffies;
+
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * It checks each scheduling domain to see if it is due to be balanced,
+ * and initiates a balancing operation if so.
+ *
+ * Balancing parameters are set up in init_sched_domains.
+ */
+static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle)
+{
+	int continue_balancing = 1;
+	int cpu = rq->cpu;
+	int busy = idle != CPU_IDLE && !sched_idle_cpu(cpu);
+	unsigned long interval;
+	struct sched_domain *sd;
+	/* Earliest time when we have to do rebalance again */
+	unsigned long next_balance = jiffies + 60*HZ;
+	int update_next_balance = 0;
+	int need_serialize, need_decay = 0;
+	u64 max_cost = 0;
+
+	rcu_read_lock();
+	for_each_domain(cpu, sd) {
+		/*
+		 * Decay the newidle max times here because this is a regular
+		 * visit to all the domains.
+		 */
+		need_decay = update_newidle_cost(sd, 0);
+		max_cost += sd->max_newidle_lb_cost;
+
+		/*
+		 * Stop the load balance at this level. There is another
+		 * CPU in our sched group which is doing load balancing more
+		 * actively.
+		 */
+		if (!continue_balancing) {
+			if (need_decay)
+				continue;
+			break;
+		}
+
+		interval = get_sd_balance_interval(sd, busy);
+
+		need_serialize = sd->flags & SD_SERIALIZE;
+		if (need_serialize) {
+			if (!spin_trylock(&balancing))
+				goto out;
+		}
+
+		if (time_after_eq(jiffies, sd->last_balance + interval)) {
+			if (load_balance(cpu, rq, sd, idle, &continue_balancing)) {
+				/*
+				 * The LBF_DST_PINNED logic could have changed
+				 * env->dst_cpu, so we can't know our idle
+				 * state even if we migrated tasks. Update it.
+				 */
+				idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE;
+				busy = idle != CPU_IDLE && !sched_idle_cpu(cpu);
+			}
+			sd->last_balance = jiffies;
+			interval = get_sd_balance_interval(sd, busy);
+		}
+		if (need_serialize)
+			spin_unlock(&balancing);
+out:
+		if (time_after(next_balance, sd->last_balance + interval)) {
+			next_balance = sd->last_balance + interval;
+			update_next_balance = 1;
+		}
+	}
+	if (need_decay) {
+		/*
+		 * Ensure the rq-wide value also decays but keep it at a
+		 * reasonable floor to avoid funnies with rq->avg_idle.
+		 */
+		rq->max_idle_balance_cost =
+			max((u64)sysctl_sched_migration_cost, max_cost);
+	}
+	rcu_read_unlock();
+
+	/*
+	 * next_balance will be updated only when there is a need.
+	 * When the cpu is attached to null domain for ex, it will not be
+	 * updated.
+	 */
+	if (likely(update_next_balance))
+		rq->next_balance = next_balance;
+
+}
+
+static inline int on_null_domain(struct rq *rq)
+{
+	return unlikely(!rcu_dereference_sched(rq->sd));
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+/*
+ * idle load balancing details
+ * - When one of the busy CPUs notice that there may be an idle rebalancing
+ *   needed, they will kick the idle load balancer, which then does idle
+ *   load balancing for all the idle CPUs.
+ * - HK_TYPE_MISC CPUs are used for this task, because HK_TYPE_SCHED not set
+ *   anywhere yet.
+ */
+
+static inline int find_new_ilb(void)
+{
+	int ilb;
+	const struct cpumask *hk_mask;
+
+	hk_mask = housekeeping_cpumask(HK_TYPE_MISC);
+
+	for_each_cpu_and(ilb, nohz.idle_cpus_mask, hk_mask) {
+
+		if (ilb == smp_processor_id())
+			continue;
+
+		if (idle_cpu(ilb))
+			return ilb;
+	}
+
+	return nr_cpu_ids;
+}
+
+/*
+ * Kick a CPU to do the nohz balancing, if it is time for it. We pick any
+ * idle CPU in the HK_TYPE_MISC housekeeping set (if there is one).
+ */
+static void kick_ilb(unsigned int flags)
+{
+	int ilb_cpu;
+
+	/*
+	 * Increase nohz.next_balance only when if full ilb is triggered but
+	 * not if we only update stats.
+	 */
+	if (flags & NOHZ_BALANCE_KICK)
+		nohz.next_balance = jiffies+1;
+
+	ilb_cpu = find_new_ilb();
+
+	if (ilb_cpu >= nr_cpu_ids)
+		return;
+
+	/*
+	 * Access to rq::nohz_csd is serialized by NOHZ_KICK_MASK; he who sets
+	 * the first flag owns it; cleared by nohz_csd_func().
+	 */
+	flags = atomic_fetch_or(flags, nohz_flags(ilb_cpu));
+	if (flags & NOHZ_KICK_MASK)
+		return;
+
+	/*
+	 * This way we generate an IPI on the target CPU which
+	 * is idle. And the softirq performing nohz idle load balance
+	 * will be run before returning from the IPI.
+	 */
+	smp_call_function_single_async(ilb_cpu, &cpu_rq(ilb_cpu)->nohz_csd);
+}
+
+/*
+ * Current decision point for kicking the idle load balancer in the presence
+ * of idle CPUs in the system.
+ */
+static void nohz_balancer_kick(struct rq *rq)
+{
+	unsigned long now = jiffies;
+	struct sched_domain_shared *sds;
+	struct sched_domain *sd;
+	int nr_busy, i, cpu = rq->cpu;
+	unsigned int flags = 0;
+
+	if (unlikely(rq->idle_balance))
+		return;
+
+	/*
+	 * We may be recently in ticked or tickless idle mode. At the first
+	 * busy tick after returning from idle, we will update the busy stats.
+	 */
+	nohz_balance_exit_idle(rq);
+
+	/*
+	 * None are in tickless mode and hence no need for NOHZ idle load
+	 * balancing.
+	 */
+	if (likely(!atomic_read(&nohz.nr_cpus)))
+		return;
+
+	if (READ_ONCE(nohz.has_blocked) &&
+	    time_after(now, READ_ONCE(nohz.next_blocked)))
+		flags = NOHZ_STATS_KICK;
+
+	if (time_before(now, nohz.next_balance))
+		goto out;
+
+	if (rq->nr_running >= 2) {
+		flags = NOHZ_STATS_KICK | NOHZ_BALANCE_KICK;
+		goto out;
+	}
+
+	rcu_read_lock();
+
+	sd = rcu_dereference(rq->sd);
+	if (sd) {
+		/*
+		 * If there's a CFS task and the current CPU has reduced
+		 * capacity; kick the ILB to see if there's a better CPU to run
+		 * on.
+		 */
+		if (rq->cfs.h_nr_running >= 1 && check_cpu_capacity(rq, sd)) {
+			flags = NOHZ_STATS_KICK | NOHZ_BALANCE_KICK;
+			goto unlock;
+		}
+	}
+
+	sd = rcu_dereference(per_cpu(sd_asym_packing, cpu));
+	if (sd) {
+		/*
+		 * When ASYM_PACKING; see if there's a more preferred CPU
+		 * currently idle; in which case, kick the ILB to move tasks
+		 * around.
+		 */
+		for_each_cpu_and(i, sched_domain_span(sd), nohz.idle_cpus_mask) {
+			if (sched_asym_prefer(i, cpu)) {
+				flags = NOHZ_STATS_KICK | NOHZ_BALANCE_KICK;
+				goto unlock;
+			}
+		}
+	}
+
+	sd = rcu_dereference(per_cpu(sd_asym_cpucapacity, cpu));
+	if (sd) {
+		/*
+		 * When ASYM_CPUCAPACITY; see if there's a higher capacity CPU
+		 * to run the misfit task on.
+		 */
+		if (check_misfit_status(rq, sd)) {
+			flags = NOHZ_STATS_KICK | NOHZ_BALANCE_KICK;
+			goto unlock;
+		}
+
+		/*
+		 * For asymmetric systems, we do not want to nicely balance
+		 * cache use, instead we want to embrace asymmetry and only
+		 * ensure tasks have enough CPU capacity.
+		 *
+		 * Skip the LLC logic because it's not relevant in that case.
+		 */
+		goto unlock;
+	}
+
+	sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+	if (sds) {
+		/*
+		 * If there is an imbalance between LLC domains (IOW we could
+		 * increase the overall cache use), we need some less-loaded LLC
+		 * domain to pull some load. Likewise, we may need to spread
+		 * load within the current LLC domain (e.g. packed SMT cores but
+		 * other CPUs are idle). We can't really know from here how busy
+		 * the others are - so just get a nohz balance going if it looks
+		 * like this LLC domain has tasks we could move.
+		 */
+		nr_busy = atomic_read(&sds->nr_busy_cpus);
+		if (nr_busy > 1) {
+			flags = NOHZ_STATS_KICK | NOHZ_BALANCE_KICK;
+			goto unlock;
+		}
+	}
+unlock:
+	rcu_read_unlock();
+out:
+	if (READ_ONCE(nohz.needs_update))
+		flags |= NOHZ_NEXT_KICK;
+
+	if (flags)
+		kick_ilb(flags);
+}
+
+static void set_cpu_sd_state_busy(int cpu)
+{
+	struct sched_domain *sd;
+
+	rcu_read_lock();
+	sd = rcu_dereference(per_cpu(sd_llc, cpu));
+
+	if (!sd || !sd->nohz_idle)
+		goto unlock;
+	sd->nohz_idle = 0;
+
+	atomic_inc(&sd->shared->nr_busy_cpus);
+unlock:
+	rcu_read_unlock();
+}
+
+void nohz_balance_exit_idle(struct rq *rq)
+{
+	SCHED_WARN_ON(rq != this_rq());
+
+	if (likely(!rq->nohz_tick_stopped))
+		return;
+
+	rq->nohz_tick_stopped = 0;
+	cpumask_clear_cpu(rq->cpu, nohz.idle_cpus_mask);
+	atomic_dec(&nohz.nr_cpus);
+
+	set_cpu_sd_state_busy(rq->cpu);
+}
+
+static void set_cpu_sd_state_idle(int cpu)
+{
+	struct sched_domain *sd;
+
+	rcu_read_lock();
+	sd = rcu_dereference(per_cpu(sd_llc, cpu));
+
+	if (!sd || sd->nohz_idle)
+		goto unlock;
+	sd->nohz_idle = 1;
+
+	atomic_dec(&sd->shared->nr_busy_cpus);
+unlock:
+	rcu_read_unlock();
+}
+
+/*
+ * This routine will record that the CPU is going idle with tick stopped.
+ * This info will be used in performing idle load balancing in the future.
+ */
+void nohz_balance_enter_idle(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	SCHED_WARN_ON(cpu != smp_processor_id());
+
+	/* If this CPU is going down, then nothing needs to be done: */
+	if (!cpu_active(cpu))
+		return;
+
+	/* Spare idle load balancing on CPUs that don't want to be disturbed: */
+	if (!housekeeping_cpu(cpu, HK_TYPE_SCHED))
+		return;
+
+	/*
+	 * Can be set safely without rq->lock held
+	 * If a clear happens, it will have evaluated last additions because
+	 * rq->lock is held during the check and the clear
+	 */
+	rq->has_blocked_load = 1;
+
+	/*
+	 * The tick is still stopped but load could have been added in the
+	 * meantime. We set the nohz.has_blocked flag to trig a check of the
+	 * *_avg. The CPU is already part of nohz.idle_cpus_mask so the clear
+	 * of nohz.has_blocked can only happen after checking the new load
+	 */
+	if (rq->nohz_tick_stopped)
+		goto out;
+
+	/* If we're a completely isolated CPU, we don't play: */
+	if (on_null_domain(rq))
+		return;
+
+	rq->nohz_tick_stopped = 1;
+
+	cpumask_set_cpu(cpu, nohz.idle_cpus_mask);
+	atomic_inc(&nohz.nr_cpus);
+
+	/*
+	 * Ensures that if nohz_idle_balance() fails to observe our
+	 * @idle_cpus_mask store, it must observe the @has_blocked
+	 * and @needs_update stores.
+	 */
+	smp_mb__after_atomic();
+
+	set_cpu_sd_state_idle(cpu);
+
+	WRITE_ONCE(nohz.needs_update, 1);
+out:
+	/*
+	 * Each time a cpu enter idle, we assume that it has blocked load and
+	 * enable the periodic update of the load of idle cpus
+	 */
+	WRITE_ONCE(nohz.has_blocked, 1);
+}
+
+static bool update_nohz_stats(struct rq *rq)
+{
+	unsigned int cpu = rq->cpu;
+
+	if (!rq->has_blocked_load)
+		return false;
+
+	if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask))
+		return false;
+
+	if (!time_after(jiffies, READ_ONCE(rq->last_blocked_load_update_tick)))
+		return true;
+
+	update_blocked_averages(cpu);
+
+	return rq->has_blocked_load;
+}
+
+/*
+ * Internal function that runs load balance for all idle cpus. The load balance
+ * can be a simple update of blocked load or a complete load balance with
+ * tasks movement depending of flags.
+ */
+static void _nohz_idle_balance(struct rq *this_rq, unsigned int flags)
+{
+	/* Earliest time when we have to do rebalance again */
+	unsigned long now = jiffies;
+	unsigned long next_balance = now + 60*HZ;
+	bool has_blocked_load = false;
+	int update_next_balance = 0;
+	int this_cpu = this_rq->cpu;
+	int balance_cpu;
+	struct rq *rq;
+
+	SCHED_WARN_ON((flags & NOHZ_KICK_MASK) == NOHZ_BALANCE_KICK);
+
+	/*
+	 * We assume there will be no idle load after this update and clear
+	 * the has_blocked flag. If a cpu enters idle in the mean time, it will
+	 * set the has_blocked flag and trigger another update of idle load.
+	 * Because a cpu that becomes idle, is added to idle_cpus_mask before
+	 * setting the flag, we are sure to not clear the state and not
+	 * check the load of an idle cpu.
+	 *
+	 * Same applies to idle_cpus_mask vs needs_update.
+	 */
+	if (flags & NOHZ_STATS_KICK)
+		WRITE_ONCE(nohz.has_blocked, 0);
+	if (flags & NOHZ_NEXT_KICK)
+		WRITE_ONCE(nohz.needs_update, 0);
+
+	/*
+	 * Ensures that if we miss the CPU, we must see the has_blocked
+	 * store from nohz_balance_enter_idle().
+	 */
+	smp_mb();
+
+	/*
+	 * Start with the next CPU after this_cpu so we will end with this_cpu and let a
+	 * chance for other idle cpu to pull load.
+	 */
+	for_each_cpu_wrap(balance_cpu,  nohz.idle_cpus_mask, this_cpu+1) {
+		if (!idle_cpu(balance_cpu))
+			continue;
+
+		/*
+		 * If this CPU gets work to do, stop the load balancing
+		 * work being done for other CPUs. Next load
+		 * balancing owner will pick it up.
+		 */
+		if (need_resched()) {
+			if (flags & NOHZ_STATS_KICK)
+				has_blocked_load = true;
+			if (flags & NOHZ_NEXT_KICK)
+				WRITE_ONCE(nohz.needs_update, 1);
+			goto abort;
+		}
+
+		rq = cpu_rq(balance_cpu);
+
+		if (flags & NOHZ_STATS_KICK)
+			has_blocked_load |= update_nohz_stats(rq);
+
+		/*
+		 * If time for next balance is due,
+		 * do the balance.
+		 */
+		if (time_after_eq(jiffies, rq->next_balance)) {
+			struct rq_flags rf;
+
+			rq_lock_irqsave(rq, &rf);
+			update_rq_clock(rq);
+			rq_unlock_irqrestore(rq, &rf);
+
+			if (flags & NOHZ_BALANCE_KICK)
+				rebalance_domains(rq, CPU_IDLE);
+		}
+
+		if (time_after(next_balance, rq->next_balance)) {
+			next_balance = rq->next_balance;
+			update_next_balance = 1;
+		}
+	}
+
+	/*
+	 * next_balance will be updated only when there is a need.
+	 * When the CPU is attached to null domain for ex, it will not be
+	 * updated.
+	 */
+	if (likely(update_next_balance))
+		nohz.next_balance = next_balance;
+
+	if (flags & NOHZ_STATS_KICK)
+		WRITE_ONCE(nohz.next_blocked,
+			   now + msecs_to_jiffies(LOAD_AVG_PERIOD));
+
+abort:
+	/* There is still blocked load, enable periodic update */
+	if (has_blocked_load)
+		WRITE_ONCE(nohz.has_blocked, 1);
+}
+
+/*
+ * In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the
+ * rebalancing for all the cpus for whom scheduler ticks are stopped.
+ */
+static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
+{
+	unsigned int flags = this_rq->nohz_idle_balance;
+
+	if (!flags)
+		return false;
+
+	this_rq->nohz_idle_balance = 0;
+
+	if (idle != CPU_IDLE)
+		return false;
+
+	_nohz_idle_balance(this_rq, flags);
+
+	return true;
+}
+
+/*
+ * Check if we need to run the ILB for updating blocked load before entering
+ * idle state.
+ */
+void nohz_run_idle_balance(int cpu)
+{
+	unsigned int flags;
+
+	flags = atomic_fetch_andnot(NOHZ_NEWILB_KICK, nohz_flags(cpu));
+
+	/*
+	 * Update the blocked load only if no SCHED_SOFTIRQ is about to happen
+	 * (ie NOHZ_STATS_KICK set) and will do the same.
+	 */
+	if ((flags == NOHZ_NEWILB_KICK) && !need_resched())
+		_nohz_idle_balance(cpu_rq(cpu), NOHZ_STATS_KICK);
+}
+
+static void nohz_newidle_balance(struct rq *this_rq)
+{
+	int this_cpu = this_rq->cpu;
+
+	/*
+	 * This CPU doesn't want to be disturbed by scheduler
+	 * housekeeping
+	 */
+	if (!housekeeping_cpu(this_cpu, HK_TYPE_SCHED))
+		return;
+
+	/* Will wake up very soon. No time for doing anything else*/
+	if (this_rq->avg_idle < sysctl_sched_migration_cost)
+		return;
+
+	/* Don't need to update blocked load of idle CPUs*/
+	if (!READ_ONCE(nohz.has_blocked) ||
+	    time_before(jiffies, READ_ONCE(nohz.next_blocked)))
+		return;
+
+	/*
+	 * Set the need to trigger ILB in order to update blocked load
+	 * before entering idle state.
+	 */
+	atomic_or(NOHZ_NEWILB_KICK, nohz_flags(this_cpu));
+}
+
+#else /* !CONFIG_NO_HZ_COMMON */
+static inline void nohz_balancer_kick(struct rq *rq) { }
+
+static inline bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
+{
+	return false;
+}
+
+static inline void nohz_newidle_balance(struct rq *this_rq) { }
+#endif /* CONFIG_NO_HZ_COMMON */
+
+/*
+ * newidle_balance is called by schedule() if this_cpu is about to become
+ * idle. Attempts to pull tasks from other CPUs.
+ *
+ * Returns:
+ *   < 0 - we released the lock and there are !fair tasks present
+ *     0 - failed, no new tasks
+ *   > 0 - success, new (fair) tasks present
+ */
+static int newidle_balance(struct rq *this_rq, struct rq_flags *rf)
+{
+	unsigned long next_balance = jiffies + HZ;
+	int this_cpu = this_rq->cpu;
+	u64 t0, t1, curr_cost = 0;
+	struct sched_domain *sd;
+	int pulled_task = 0;
+
+	update_misfit_status(NULL, this_rq);
+
+	/*
+	 * There is a task waiting to run. No need to search for one.
+	 * Return 0; the task will be enqueued when switching to idle.
+	 */
+	if (this_rq->ttwu_pending)
+		return 0;
+
+	/*
+	 * We must set idle_stamp _before_ calling idle_balance(), such that we
+	 * measure the duration of idle_balance() as idle time.
+	 */
+	this_rq->idle_stamp = rq_clock(this_rq);
+
+	/*
+	 * Do not pull tasks towards !active CPUs...
+	 */
+	if (!cpu_active(this_cpu))
+		return 0;
+
+	/*
+	 * This is OK, because current is on_cpu, which avoids it being picked
+	 * for load-balance and preemption/IRQs are still disabled avoiding
+	 * further scheduler activity on it and we're being very careful to
+	 * re-start the picking loop.
+	 */
+	rq_unpin_lock(this_rq, rf);
+
+	rcu_read_lock();
+	sd = rcu_dereference_check_sched_domain(this_rq->sd);
+
+	if (!READ_ONCE(this_rq->rd->overload) ||
+	    (sd && this_rq->avg_idle < sd->max_newidle_lb_cost)) {
+
+		if (sd)
+			update_next_balance(sd, &next_balance);
+		rcu_read_unlock();
+
+		goto out;
+	}
+	rcu_read_unlock();
+
+	raw_spin_rq_unlock(this_rq);
+
+	t0 = sched_clock_cpu(this_cpu);
+	update_blocked_averages(this_cpu);
+
+	rcu_read_lock();
+	for_each_domain(this_cpu, sd) {
+		int continue_balancing = 1;
+		u64 domain_cost;
+
+		update_next_balance(sd, &next_balance);
+
+		if (this_rq->avg_idle < curr_cost + sd->max_newidle_lb_cost)
+			break;
+
+		if (sd->flags & SD_BALANCE_NEWIDLE) {
+
+			pulled_task = load_balance(this_cpu, this_rq,
+						   sd, CPU_NEWLY_IDLE,
+						   &continue_balancing);
+
+			t1 = sched_clock_cpu(this_cpu);
+			domain_cost = t1 - t0;
+			update_newidle_cost(sd, domain_cost);
+
+			curr_cost += domain_cost;
+			t0 = t1;
+		}
+
+		/*
+		 * Stop searching for tasks to pull if there are
+		 * now runnable tasks on this rq.
+		 */
+		if (pulled_task || this_rq->nr_running > 0 ||
+		    this_rq->ttwu_pending)
+			break;
+	}
+	rcu_read_unlock();
+
+	raw_spin_rq_lock(this_rq);
+
+	if (curr_cost > this_rq->max_idle_balance_cost)
+		this_rq->max_idle_balance_cost = curr_cost;
+
+	/*
+	 * While browsing the domains, we released the rq lock, a task could
+	 * have been enqueued in the meantime. Since we're not going idle,
+	 * pretend we pulled a task.
+	 */
+	if (this_rq->cfs.h_nr_running && !pulled_task)
+		pulled_task = 1;
+
+	/* Is there a task of a high priority class? */
+	if (this_rq->nr_running != this_rq->cfs.h_nr_running)
+		pulled_task = -1;
+
+out:
+	/* Move the next balance forward */
+	if (time_after(this_rq->next_balance, next_balance))
+		this_rq->next_balance = next_balance;
+
+	if (pulled_task)
+		this_rq->idle_stamp = 0;
+	else
+		nohz_newidle_balance(this_rq);
+
+	rq_repin_lock(this_rq, rf);
+
+	return pulled_task;
+}
+
+/*
+ * run_rebalance_domains is triggered when needed from the scheduler tick.
+ * Also triggered for nohz idle balancing (with nohz_balancing_kick set).
+ */
+static __latent_entropy void run_rebalance_domains(struct softirq_action *h)
+{
+	struct rq *this_rq = this_rq();
+	enum cpu_idle_type idle = this_rq->idle_balance ?
+						CPU_IDLE : CPU_NOT_IDLE;
+
+	/*
+	 * If this CPU has a pending nohz_balance_kick, then do the
+	 * balancing on behalf of the other idle CPUs whose ticks are
+	 * stopped. Do nohz_idle_balance *before* rebalance_domains to
+	 * give the idle CPUs a chance to load balance. Else we may
+	 * load balance only within the local sched_domain hierarchy
+	 * and abort nohz_idle_balance altogether if we pull some load.
+	 */
+	if (nohz_idle_balance(this_rq, idle))
+		return;
+
+	/* normal load balance */
+	update_blocked_averages(this_rq->cpu);
+	rebalance_domains(this_rq, idle);
+}
+
+/*
+ * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
+ */
+void trigger_load_balance(struct rq *rq)
+{
+	/*
+	 * Don't need to rebalance while attached to NULL domain or
+	 * runqueue CPU is not active
+	 */
+	if (unlikely(on_null_domain(rq) || !cpu_active(cpu_of(rq))))
+		return;
+
+	if (time_after_eq(jiffies, rq->next_balance))
+		raise_softirq(SCHED_SOFTIRQ);
+
+	nohz_balancer_kick(rq);
+}
+
+static void rq_online_fair(struct rq *rq)
+{
+	update_sysctl();
+
+	update_runtime_enabled(rq);
+}
+
+static void rq_offline_fair(struct rq *rq)
+{
+	update_sysctl();
+
+	/* Ensure any throttled groups are reachable by pick_next_task */
+	unthrottle_offline_cfs_rqs(rq);
+}
+
+#endif /* CONFIG_SMP */
+
+#ifdef CONFIG_SCHED_CORE
+static inline bool
+__entity_slice_used(struct sched_entity *se, int min_nr_tasks)
+{
+	u64 slice = sched_slice(cfs_rq_of(se), se);
+	u64 rtime = se->sum_exec_runtime - se->prev_sum_exec_runtime;
+
+	return (rtime * min_nr_tasks > slice);
+}
+
+#define MIN_NR_TASKS_DURING_FORCEIDLE	2
+static inline void task_tick_core(struct rq *rq, struct task_struct *curr)
+{
+	if (!sched_core_enabled(rq))
+		return;
+
+	/*
+	 * If runqueue has only one task which used up its slice and
+	 * if the sibling is forced idle, then trigger schedule to
+	 * give forced idle task a chance.
+	 *
+	 * sched_slice() considers only this active rq and it gets the
+	 * whole slice. But during force idle, we have siblings acting
+	 * like a single runqueue and hence we need to consider runnable
+	 * tasks on this CPU and the forced idle CPU. Ideally, we should
+	 * go through the forced idle rq, but that would be a perf hit.
+	 * We can assume that the forced idle CPU has at least
+	 * MIN_NR_TASKS_DURING_FORCEIDLE - 1 tasks and use that to check
+	 * if we need to give up the CPU.
+	 */
+	if (rq->core->core_forceidle_count && rq->cfs.nr_running == 1 &&
+	    __entity_slice_used(&curr->se, MIN_NR_TASKS_DURING_FORCEIDLE))
+		resched_curr(rq);
+}
+
+/*
+ * se_fi_update - Update the cfs_rq->min_vruntime_fi in a CFS hierarchy if needed.
+ */
+static void se_fi_update(struct sched_entity *se, unsigned int fi_seq, bool forceidle)
+{
+	for_each_sched_entity(se) {
+		struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+		if (forceidle) {
+			if (cfs_rq->forceidle_seq == fi_seq)
+				break;
+			cfs_rq->forceidle_seq = fi_seq;
+		}
+
+		cfs_rq->min_vruntime_fi = cfs_rq->min_vruntime;
+	}
+}
+
+void task_vruntime_update(struct rq *rq, struct task_struct *p, bool in_fi)
+{
+	struct sched_entity *se = &p->se;
+
+	if (p->sched_class != &fair_sched_class)
+		return;
+
+	se_fi_update(se, rq->core->core_forceidle_seq, in_fi);
+}
+
+bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool in_fi)
+{
+	struct rq *rq = task_rq(a);
+	struct sched_entity *sea = &a->se;
+	struct sched_entity *seb = &b->se;
+	struct cfs_rq *cfs_rqa;
+	struct cfs_rq *cfs_rqb;
+	s64 delta;
+
+	SCHED_WARN_ON(task_rq(b)->core != rq->core);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	/*
+	 * Find an se in the hierarchy for tasks a and b, such that the se's
+	 * are immediate siblings.
+	 */
+	while (sea->cfs_rq->tg != seb->cfs_rq->tg) {
+		int sea_depth = sea->depth;
+		int seb_depth = seb->depth;
+
+		if (sea_depth >= seb_depth)
+			sea = parent_entity(sea);
+		if (sea_depth <= seb_depth)
+			seb = parent_entity(seb);
+	}
+
+	se_fi_update(sea, rq->core->core_forceidle_seq, in_fi);
+	se_fi_update(seb, rq->core->core_forceidle_seq, in_fi);
+
+	cfs_rqa = sea->cfs_rq;
+	cfs_rqb = seb->cfs_rq;
+#else
+	cfs_rqa = &task_rq(a)->cfs;
+	cfs_rqb = &task_rq(b)->cfs;
+#endif
+
+	/*
+	 * Find delta after normalizing se's vruntime with its cfs_rq's
+	 * min_vruntime_fi, which would have been updated in prior calls
+	 * to se_fi_update().
+	 */
+	delta = (s64)(sea->vruntime - seb->vruntime) +
+		(s64)(cfs_rqb->min_vruntime_fi - cfs_rqa->min_vruntime_fi);
+
+	return delta > 0;
+}
+#else
+static inline void task_tick_core(struct rq *rq, struct task_struct *curr) {}
+#endif
+
+/*
+ * scheduler tick hitting a task of our scheduling class.
+ *
+ * NOTE: This function can be called remotely by the tick offload that
+ * goes along full dynticks. Therefore no local assumption can be made
+ * and everything must be accessed through the @rq and @curr passed in
+ * parameters.
+ */
+static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
+{
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se = &curr->se;
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+		entity_tick(cfs_rq, se, queued);
+	}
+
+	if (static_branch_unlikely(&sched_numa_balancing))
+		task_tick_numa(rq, curr);
+
+	update_misfit_status(curr, rq);
+	update_overutilized_status(task_rq(curr));
+
+	task_tick_core(rq, curr);
+}
+
+/*
+ * called on fork with the child task as argument from the parent's context
+ *  - child not yet on the tasklist
+ *  - preemption disabled
+ */
+static void task_fork_fair(struct task_struct *p)
+{
+	struct cfs_rq *cfs_rq;
+	struct sched_entity *se = &p->se, *curr;
+	struct rq *rq = this_rq();
+	struct rq_flags rf;
+
+	rq_lock(rq, &rf);
+	update_rq_clock(rq);
+
+	cfs_rq = task_cfs_rq(current);
+	curr = cfs_rq->curr;
+	if (curr) {
+		update_curr(cfs_rq);
+		se->vruntime = curr->vruntime;
+	}
+	place_entity(cfs_rq, se, 1);
+
+	if (sysctl_sched_child_runs_first && curr && entity_before(curr, se)) {
+		/*
+		 * Upon rescheduling, sched_class::put_prev_task() will place
+		 * 'current' within the tree based on its new key value.
+		 */
+		swap(curr->vruntime, se->vruntime);
+		resched_curr(rq);
+	}
+
+	se->vruntime -= cfs_rq->min_vruntime;
+	rq_unlock(rq, &rf);
+}
+
+/*
+ * Priority of the task has changed. Check to see if we preempt
+ * the current task.
+ */
+static void
+prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
+{
+	if (!task_on_rq_queued(p))
+		return;
+
+	if (rq->cfs.nr_running == 1)
+		return;
+
+	/*
+	 * Reschedule if we are currently running on this runqueue and
+	 * our priority decreased, or if we are not currently running on
+	 * this runqueue and our priority is higher than the current's
+	 */
+	if (task_current(rq, p)) {
+		if (p->prio > oldprio)
+			resched_curr(rq);
+	} else
+		check_preempt_curr(rq, p, 0);
+}
+
+static inline bool vruntime_normalized(struct task_struct *p)
+{
+	struct sched_entity *se = &p->se;
+
+	/*
+	 * In both the TASK_ON_RQ_QUEUED and TASK_ON_RQ_MIGRATING cases,
+	 * the dequeue_entity(.flags=0) will already have normalized the
+	 * vruntime.
+	 */
+	if (p->on_rq)
+		return true;
+
+	/*
+	 * When !on_rq, vruntime of the task has usually NOT been normalized.
+	 * But there are some cases where it has already been normalized:
+	 *
+	 * - A forked child which is waiting for being woken up by
+	 *   wake_up_new_task().
+	 * - A task which has been woken up by try_to_wake_up() and
+	 *   waiting for actually being woken up by sched_ttwu_pending().
+	 */
+	if (!se->sum_exec_runtime ||
+	    (READ_ONCE(p->__state) == TASK_WAKING && p->sched_remote_wakeup))
+		return true;
+
+	return false;
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/*
+ * Propagate the changes of the sched_entity across the tg tree to make it
+ * visible to the root
+ */
+static void propagate_entity_cfs_rq(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+	if (cfs_rq_throttled(cfs_rq))
+		return;
+
+	if (!throttled_hierarchy(cfs_rq))
+		list_add_leaf_cfs_rq(cfs_rq);
+
+	/* Start to propagate at parent */
+	se = se->parent;
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+
+		update_load_avg(cfs_rq, se, UPDATE_TG);
+
+		if (cfs_rq_throttled(cfs_rq))
+			break;
+
+		if (!throttled_hierarchy(cfs_rq))
+			list_add_leaf_cfs_rq(cfs_rq);
+	}
+}
+#else
+static void propagate_entity_cfs_rq(struct sched_entity *se) { }
+#endif
+
+static void detach_entity_cfs_rq(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+#ifdef CONFIG_SMP
+	/*
+	 * In case the task sched_avg hasn't been attached:
+	 * - A forked task which hasn't been woken up by wake_up_new_task().
+	 * - A task which has been woken up by try_to_wake_up() but is
+	 *   waiting for actually being woken up by sched_ttwu_pending().
+	 */
+	if (!se->avg.last_update_time)
+		return;
+#endif
+
+	/* Catch up with the cfs_rq and remove our load when we leave */
+	update_load_avg(cfs_rq, se, 0);
+	detach_entity_load_avg(cfs_rq, se);
+	update_tg_load_avg(cfs_rq);
+	propagate_entity_cfs_rq(se);
+}
+
+static void attach_entity_cfs_rq(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+	/* Synchronize entity with its cfs_rq */
+	update_load_avg(cfs_rq, se, sched_feat(ATTACH_AGE_LOAD) ? 0 : SKIP_AGE_LOAD);
+	attach_entity_load_avg(cfs_rq, se);
+	update_tg_load_avg(cfs_rq);
+	propagate_entity_cfs_rq(se);
+}
+
+static void detach_task_cfs_rq(struct task_struct *p)
+{
+	struct sched_entity *se = &p->se;
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+	if (!vruntime_normalized(p)) {
+		/*
+		 * Fix up our vruntime so that the current sleep doesn't
+		 * cause 'unlimited' sleep bonus.
+		 */
+		place_entity(cfs_rq, se, 0);
+		se->vruntime -= cfs_rq->min_vruntime;
+	}
+
+	detach_entity_cfs_rq(se);
+}
+
+static void attach_task_cfs_rq(struct task_struct *p)
+{
+	struct sched_entity *se = &p->se;
+	struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+	attach_entity_cfs_rq(se);
+
+	if (!vruntime_normalized(p))
+		se->vruntime += cfs_rq->min_vruntime;
+}
+
+static void switched_from_fair(struct rq *rq, struct task_struct *p)
+{
+	detach_task_cfs_rq(p);
+}
+
+static void switched_to_fair(struct rq *rq, struct task_struct *p)
+{
+	attach_task_cfs_rq(p);
+
+	if (task_on_rq_queued(p)) {
+		/*
+		 * We were most likely switched from sched_rt, so
+		 * kick off the schedule if running, otherwise just see
+		 * if we can still preempt the current task.
+		 */
+		if (task_current(rq, p))
+			resched_curr(rq);
+		else
+			check_preempt_curr(rq, p, 0);
+	}
+}
+
+/* Account for a task changing its policy or group.
+ *
+ * This routine is mostly called to set cfs_rq->curr field when a task
+ * migrates between groups/classes.
+ */
+static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool first)
+{
+	struct sched_entity *se = &p->se;
+
+#ifdef CONFIG_SMP
+	if (task_on_rq_queued(p)) {
+		/*
+		 * Move the next running task to the front of the list, so our
+		 * cfs_tasks list becomes MRU one.
+		 */
+		list_move(&se->group_node, &rq->cfs_tasks);
+	}
+#endif
+
+	for_each_sched_entity(se) {
+		struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+		set_next_entity(cfs_rq, se);
+		/* ensure bandwidth has been allocated on our new cfs_rq */
+		account_cfs_rq_runtime(cfs_rq, 0);
+	}
+}
+
+void init_cfs_rq(struct cfs_rq *cfs_rq)
+{
+	cfs_rq->tasks_timeline = RB_ROOT_CACHED;
+	u64_u32_store(cfs_rq->min_vruntime, (u64)(-(1LL << 20)));
+#ifdef CONFIG_SMP
+	raw_spin_lock_init(&cfs_rq->removed.lock);
+#endif
+}
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void task_change_group_fair(struct task_struct *p)
+{
+	/*
+	 * We couldn't detach or attach a forked task which
+	 * hasn't been woken up by wake_up_new_task().
+	 */
+	if (READ_ONCE(p->__state) == TASK_NEW)
+		return;
+
+	detach_task_cfs_rq(p);
+
+#ifdef CONFIG_SMP
+	/* Tell se's cfs_rq has been changed -- migrated */
+	p->se.avg.last_update_time = 0;
+#endif
+	set_task_rq(p, task_cpu(p));
+	attach_task_cfs_rq(p);
+}
+
+void free_fair_sched_group(struct task_group *tg)
+{
+	int i;
+
+	for_each_possible_cpu(i) {
+		if (tg->cfs_rq)
+			kfree(tg->cfs_rq[i]);
+		if (tg->se)
+			kfree(tg->se[i]);
+	}
+
+	kfree(tg->cfs_rq);
+	kfree(tg->se);
+}
+
+int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
+{
+	struct sched_entity *se;
+	struct cfs_rq *cfs_rq;
+	int i;
+
+	tg->cfs_rq = kcalloc(nr_cpu_ids, sizeof(cfs_rq), GFP_KERNEL);
+	if (!tg->cfs_rq)
+		goto err;
+	tg->se = kcalloc(nr_cpu_ids, sizeof(se), GFP_KERNEL);
+	if (!tg->se)
+		goto err;
+
+	tg->shares = NICE_0_LOAD;
+
+	init_cfs_bandwidth(tg_cfs_bandwidth(tg));
+
+	for_each_possible_cpu(i) {
+		cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
+				      GFP_KERNEL, cpu_to_node(i));
+		if (!cfs_rq)
+			goto err;
+
+		se = kzalloc_node(sizeof(struct sched_entity_stats),
+				  GFP_KERNEL, cpu_to_node(i));
+		if (!se)
+			goto err_free_rq;
+
+		init_cfs_rq(cfs_rq);
+		init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]);
+		init_entity_runnable_average(se);
+	}
+
+	return 1;
+
+err_free_rq:
+	kfree(cfs_rq);
+err:
+	return 0;
+}
+
+void online_fair_sched_group(struct task_group *tg)
+{
+	struct sched_entity *se;
+	struct rq_flags rf;
+	struct rq *rq;
+	int i;
+
+	for_each_possible_cpu(i) {
+		rq = cpu_rq(i);
+		se = tg->se[i];
+		rq_lock_irq(rq, &rf);
+		update_rq_clock(rq);
+		attach_entity_cfs_rq(se);
+		sync_throttle(tg, i);
+		rq_unlock_irq(rq, &rf);
+	}
+}
+
+void unregister_fair_sched_group(struct task_group *tg)
+{
+	unsigned long flags;
+	struct rq *rq;
+	int cpu;
+
+	destroy_cfs_bandwidth(tg_cfs_bandwidth(tg));
+
+	for_each_possible_cpu(cpu) {
+		if (tg->se[cpu])
+			remove_entity_load_avg(tg->se[cpu]);
+
+		/*
+		 * Only empty task groups can be destroyed; so we can speculatively
+		 * check on_list without danger of it being re-added.
+		 */
+		if (!tg->cfs_rq[cpu]->on_list)
+			continue;
+
+		rq = cpu_rq(cpu);
+
+		raw_spin_rq_lock_irqsave(rq, flags);
+		list_del_leaf_cfs_rq(tg->cfs_rq[cpu]);
+		raw_spin_rq_unlock_irqrestore(rq, flags);
+	}
+}
+
+void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
+			struct sched_entity *se, int cpu,
+			struct sched_entity *parent)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	cfs_rq->tg = tg;
+	cfs_rq->rq = rq;
+	init_cfs_rq_runtime(cfs_rq);
+
+	tg->cfs_rq[cpu] = cfs_rq;
+	tg->se[cpu] = se;
+
+	/* se could be NULL for root_task_group */
+	if (!se)
+		return;
+
+	if (!parent) {
+		se->cfs_rq = &rq->cfs;
+		se->depth = 0;
+	} else {
+		se->cfs_rq = parent->my_q;
+		se->depth = parent->depth + 1;
+	}
+
+	se->my_q = cfs_rq;
+	/* guarantee group entities always have weight */
+	update_load_set(&se->load, NICE_0_LOAD);
+	se->parent = parent;
+}
+
+static DEFINE_MUTEX(shares_mutex);
+
+static int __sched_group_set_shares(struct task_group *tg, unsigned long shares)
+{
+	int i;
+
+	lockdep_assert_held(&shares_mutex);
+
+	/*
+	 * We can't change the weight of the root cgroup.
+	 */
+	if (!tg->se[0])
+		return -EINVAL;
+
+	shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES));
+
+	if (tg->shares == shares)
+		return 0;
+
+	tg->shares = shares;
+	for_each_possible_cpu(i) {
+		struct rq *rq = cpu_rq(i);
+		struct sched_entity *se = tg->se[i];
+		struct rq_flags rf;
+
+		/* Propagate contribution to hierarchy */
+		rq_lock_irqsave(rq, &rf);
+		update_rq_clock(rq);
+		for_each_sched_entity(se) {
+			update_load_avg(cfs_rq_of(se), se, UPDATE_TG);
+			update_cfs_group(se);
+		}
+		rq_unlock_irqrestore(rq, &rf);
+	}
+
+	return 0;
+}
+
+int sched_group_set_shares(struct task_group *tg, unsigned long shares)
+{
+	int ret;
+
+	mutex_lock(&shares_mutex);
+	if (tg_is_idle(tg))
+		ret = -EINVAL;
+	else
+		ret = __sched_group_set_shares(tg, shares);
+	mutex_unlock(&shares_mutex);
+
+	return ret;
+}
+
+int sched_group_set_idle(struct task_group *tg, long idle)
+{
+	int i;
+
+	if (tg == &root_task_group)
+		return -EINVAL;
+
+	if (idle < 0 || idle > 1)
+		return -EINVAL;
+
+	mutex_lock(&shares_mutex);
+
+	if (tg->idle == idle) {
+		mutex_unlock(&shares_mutex);
+		return 0;
+	}
+
+	tg->idle = idle;
+
+	for_each_possible_cpu(i) {
+		struct rq *rq = cpu_rq(i);
+		struct sched_entity *se = tg->se[i];
+		struct cfs_rq *parent_cfs_rq, *grp_cfs_rq = tg->cfs_rq[i];
+		bool was_idle = cfs_rq_is_idle(grp_cfs_rq);
+		long idle_task_delta;
+		struct rq_flags rf;
+
+		rq_lock_irqsave(rq, &rf);
+
+		grp_cfs_rq->idle = idle;
+		if (WARN_ON_ONCE(was_idle == cfs_rq_is_idle(grp_cfs_rq)))
+			goto next_cpu;
+
+		if (se->on_rq) {
+			parent_cfs_rq = cfs_rq_of(se);
+			if (cfs_rq_is_idle(grp_cfs_rq))
+				parent_cfs_rq->idle_nr_running++;
+			else
+				parent_cfs_rq->idle_nr_running--;
+		}
+
+		idle_task_delta = grp_cfs_rq->h_nr_running -
+				  grp_cfs_rq->idle_h_nr_running;
+		if (!cfs_rq_is_idle(grp_cfs_rq))
+			idle_task_delta *= -1;
+
+		for_each_sched_entity(se) {
+			struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+			if (!se->on_rq)
+				break;
+
+			cfs_rq->idle_h_nr_running += idle_task_delta;
+
+			/* Already accounted at parent level and above. */
+			if (cfs_rq_is_idle(cfs_rq))
+				break;
+		}
+
+next_cpu:
+		rq_unlock_irqrestore(rq, &rf);
+	}
+
+	/* Idle groups have minimum weight. */
+	if (tg_is_idle(tg))
+		__sched_group_set_shares(tg, scale_load(WEIGHT_IDLEPRIO));
+	else
+		__sched_group_set_shares(tg, NICE_0_LOAD);
+
+	mutex_unlock(&shares_mutex);
+	return 0;
+}
+
+#else /* CONFIG_FAIR_GROUP_SCHED */
+
+void free_fair_sched_group(struct task_group *tg) { }
+
+int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
+{
+	return 1;
+}
+
+void online_fair_sched_group(struct task_group *tg) { }
+
+void unregister_fair_sched_group(struct task_group *tg) { }
+
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+
+static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task)
+{
+	struct sched_entity *se = &task->se;
+	unsigned int rr_interval = 0;
+
+	/*
+	 * Time slice is 0 for SCHED_OTHER tasks that are on an otherwise
+	 * idle runqueue:
+	 */
+	if (rq->cfs.load.weight)
+		rr_interval = NS_TO_JIFFIES(sched_slice(cfs_rq_of(se), se));
+
+	return rr_interval;
+}
+
+/*
+ * All the scheduling class methods:
+ */
+DEFINE_SCHED_CLASS(fair) = {
+
+	.enqueue_task		= enqueue_task_fair,
+	.dequeue_task		= dequeue_task_fair,
+	.yield_task		= yield_task_fair,
+	.yield_to_task		= yield_to_task_fair,
+
+	.check_preempt_curr	= check_preempt_wakeup,
+
+	.pick_next_task		= __pick_next_task_fair,
+	.put_prev_task		= put_prev_task_fair,
+	.set_next_task          = set_next_task_fair,
+
+#ifdef CONFIG_SMP
+	.balance		= balance_fair,
+	.pick_task		= pick_task_fair,
+	.select_task_rq		= select_task_rq_fair,
+	.migrate_task_rq	= migrate_task_rq_fair,
+
+	.rq_online		= rq_online_fair,
+	.rq_offline		= rq_offline_fair,
+
+	.task_dead		= task_dead_fair,
+	.set_cpus_allowed	= set_cpus_allowed_common,
+#endif
+
+	.task_tick		= task_tick_fair,
+	.task_fork		= task_fork_fair,
+
+	.prio_changed		= prio_changed_fair,
+	.switched_from		= switched_from_fair,
+	.switched_to		= switched_to_fair,
+
+	.get_rr_interval	= get_rr_interval_fair,
+
+	.update_curr		= update_curr_fair,
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	.task_change_group	= task_change_group_fair,
+#endif
+
+#ifdef CONFIG_UCLAMP_TASK
+	.uclamp_enabled		= 1,
+#endif
+};
+
+#ifdef CONFIG_SCHED_DEBUG
+void print_cfs_stats(struct seq_file *m, int cpu)
+{
+	struct cfs_rq *cfs_rq, *pos;
+
+	rcu_read_lock();
+	for_each_leaf_cfs_rq_safe(cpu_rq(cpu), cfs_rq, pos)
+		print_cfs_rq(m, cpu, cfs_rq);
+	rcu_read_unlock();
+}
+
+#ifdef CONFIG_NUMA_BALANCING
+void show_numa_stats(struct task_struct *p, struct seq_file *m)
+{
+	int node;
+	unsigned long tsf = 0, tpf = 0, gsf = 0, gpf = 0;
+	struct numa_group *ng;
+
+	rcu_read_lock();
+	ng = rcu_dereference(p->numa_group);
+	for_each_online_node(node) {
+		if (p->numa_faults) {
+			tsf = p->numa_faults[task_faults_idx(NUMA_MEM, node, 0)];
+			tpf = p->numa_faults[task_faults_idx(NUMA_MEM, node, 1)];
+		}
+		if (ng) {
+			gsf = ng->faults[task_faults_idx(NUMA_MEM, node, 0)],
+			gpf = ng->faults[task_faults_idx(NUMA_MEM, node, 1)];
+		}
+		print_numa_stats(m, node, tsf, tpf, gsf, gpf);
+	}
+	rcu_read_unlock();
+}
+#endif /* CONFIG_NUMA_BALANCING */
+#endif /* CONFIG_SCHED_DEBUG */
+
+__init void init_sched_fair_class(void)
+{
+#ifdef CONFIG_SMP
+	int i;
+
+	for_each_possible_cpu(i) {
+		zalloc_cpumask_var_node(&per_cpu(load_balance_mask, i), GFP_KERNEL, cpu_to_node(i));
+		zalloc_cpumask_var_node(&per_cpu(select_rq_mask,    i), GFP_KERNEL, cpu_to_node(i));
+	}
+
+	open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
+
+#ifdef CONFIG_NO_HZ_COMMON
+	nohz.next_balance = jiffies;
+	nohz.next_blocked = jiffies;
+	zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
+#endif
+#endif /* SMP */
+
+}
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
new file mode 100644
index 000000000..ee7f23c76
--- /dev/null
+++ b/kernel/sched/features.h
@@ -0,0 +1,103 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Only give sleepers 50% of their service deficit. This allows
+ * them to run sooner, but does not allow tons of sleepers to
+ * rip the spread apart.
+ */
+SCHED_FEAT(GENTLE_FAIR_SLEEPERS, true)
+
+/*
+ * Place new tasks ahead so that they do not starve already running
+ * tasks
+ */
+SCHED_FEAT(START_DEBIT, true)
+
+/*
+ * Prefer to schedule the task we woke last (assuming it failed
+ * wakeup-preemption), since its likely going to consume data we
+ * touched, increases cache locality.
+ */
+SCHED_FEAT(NEXT_BUDDY, false)
+
+/*
+ * Prefer to schedule the task that ran last (when we did
+ * wake-preempt) as that likely will touch the same data, increases
+ * cache locality.
+ */
+SCHED_FEAT(LAST_BUDDY, true)
+
+/*
+ * Consider buddies to be cache hot, decreases the likeliness of a
+ * cache buddy being migrated away, increases cache locality.
+ */
+SCHED_FEAT(CACHE_HOT_BUDDY, true)
+
+/*
+ * Allow wakeup-time preemption of the current task:
+ */
+SCHED_FEAT(WAKEUP_PREEMPTION, true)
+
+SCHED_FEAT(HRTICK, false)
+SCHED_FEAT(HRTICK_DL, false)
+SCHED_FEAT(DOUBLE_TICK, false)
+
+/*
+ * Decrement CPU capacity based on time not spent running tasks
+ */
+SCHED_FEAT(NONTASK_CAPACITY, true)
+
+#ifdef CONFIG_PREEMPT_RT
+SCHED_FEAT(TTWU_QUEUE, false)
+#else
+
+/*
+ * Queue remote wakeups on the target CPU and process them
+ * using the scheduler IPI. Reduces rq->lock contention/bounces.
+ */
+SCHED_FEAT(TTWU_QUEUE, true)
+#endif
+
+/*
+ * When doing wakeups, attempt to limit superfluous scans of the LLC domain.
+ */
+SCHED_FEAT(SIS_PROP, false)
+SCHED_FEAT(SIS_UTIL, true)
+
+/*
+ * Issue a WARN when we do multiple update_rq_clock() calls
+ * in a single rq->lock section. Default disabled because the
+ * annotations are not complete.
+ */
+SCHED_FEAT(WARN_DOUBLE_CLOCK, false)
+
+#ifdef HAVE_RT_PUSH_IPI
+/*
+ * In order to avoid a thundering herd attack of CPUs that are
+ * lowering their priorities at the same time, and there being
+ * a single CPU that has an RT task that can migrate and is waiting
+ * to run, where the other CPUs will try to take that CPUs
+ * rq lock and possibly create a large contention, sending an
+ * IPI to that CPU and let that CPU push the RT task to where
+ * it should go may be a better scenario.
+ */
+SCHED_FEAT(RT_PUSH_IPI, true)
+#endif
+
+SCHED_FEAT(RT_RUNTIME_SHARE, false)
+SCHED_FEAT(LB_MIN, false)
+SCHED_FEAT(ATTACH_AGE_LOAD, true)
+
+SCHED_FEAT(WA_IDLE, true)
+SCHED_FEAT(WA_WEIGHT, true)
+SCHED_FEAT(WA_BIAS, true)
+
+/*
+ * UtilEstimation. Use estimated CPU utilization.
+ */
+SCHED_FEAT(UTIL_EST, true)
+SCHED_FEAT(UTIL_EST_FASTUP, true)
+
+SCHED_FEAT(LATENCY_WARN, false)
+
+SCHED_FEAT(ALT_PERIOD, true)
+SCHED_FEAT(BASE_SLICE, true)
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
new file mode 100644
index 000000000..200a0fac0
--- /dev/null
+++ b/kernel/sched/idle.c
@@ -0,0 +1,524 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic entry points for the idle threads and
+ * implementation of the idle task scheduling class.
+ *
+ * (NOTE: these are not related to SCHED_IDLE batch scheduled
+ *        tasks which are handled in sched/fair.c )
+ */
+
+/* Linker adds these: start and end of __cpuidle functions */
+extern char __cpuidle_text_start[], __cpuidle_text_end[];
+
+/**
+ * sched_idle_set_state - Record idle state for the current CPU.
+ * @idle_state: State to record.
+ */
+void sched_idle_set_state(struct cpuidle_state *idle_state)
+{
+	idle_set_state(this_rq(), idle_state);
+}
+
+static int __read_mostly cpu_idle_force_poll;
+
+void cpu_idle_poll_ctrl(bool enable)
+{
+	if (enable) {
+		cpu_idle_force_poll++;
+	} else {
+		cpu_idle_force_poll--;
+		WARN_ON_ONCE(cpu_idle_force_poll < 0);
+	}
+}
+
+#ifdef CONFIG_GENERIC_IDLE_POLL_SETUP
+static int __init cpu_idle_poll_setup(char *__unused)
+{
+	cpu_idle_force_poll = 1;
+
+	return 1;
+}
+__setup("nohlt", cpu_idle_poll_setup);
+
+static int __init cpu_idle_nopoll_setup(char *__unused)
+{
+	cpu_idle_force_poll = 0;
+
+	return 1;
+}
+__setup("hlt", cpu_idle_nopoll_setup);
+#endif
+
+static noinline int __cpuidle cpu_idle_poll(void)
+{
+	trace_cpu_idle(0, smp_processor_id());
+	stop_critical_timings();
+	ct_idle_enter();
+	local_irq_enable();
+
+	while (!tif_need_resched() &&
+	       (cpu_idle_force_poll || tick_check_broadcast_expired()))
+		cpu_relax();
+
+	ct_idle_exit();
+	start_critical_timings();
+	trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id());
+
+	return 1;
+}
+
+/* Weak implementations for optional arch specific functions */
+void __weak arch_cpu_idle_prepare(void) { }
+void __weak arch_cpu_idle_enter(void) { }
+void __weak arch_cpu_idle_exit(void) { }
+void __weak arch_cpu_idle_dead(void) { }
+void __weak arch_cpu_idle(void)
+{
+	cpu_idle_force_poll = 1;
+	raw_local_irq_enable();
+}
+
+/**
+ * default_idle_call - Default CPU idle routine.
+ *
+ * To use when the cpuidle framework cannot be used.
+ */
+void __cpuidle default_idle_call(void)
+{
+	if (current_clr_polling_and_test()) {
+		local_irq_enable();
+	} else {
+
+		trace_cpu_idle(1, smp_processor_id());
+		stop_critical_timings();
+
+		/*
+		 * arch_cpu_idle() is supposed to enable IRQs, however
+		 * we can't do that because of RCU and tracing.
+		 *
+		 * Trace IRQs enable here, then switch off RCU, and have
+		 * arch_cpu_idle() use raw_local_irq_enable(). Note that
+		 * ct_idle_enter() relies on lockdep IRQ state, so switch that
+		 * last -- this is very similar to the entry code.
+		 */
+		trace_hardirqs_on_prepare();
+		lockdep_hardirqs_on_prepare();
+		ct_idle_enter();
+		lockdep_hardirqs_on(_THIS_IP_);
+
+		arch_cpu_idle();
+
+		/*
+		 * OK, so IRQs are enabled here, but RCU needs them disabled to
+		 * turn itself back on.. funny thing is that disabling IRQs
+		 * will cause tracing, which needs RCU. Jump through hoops to
+		 * make it 'work'.
+		 */
+		raw_local_irq_disable();
+		lockdep_hardirqs_off(_THIS_IP_);
+		ct_idle_exit();
+		lockdep_hardirqs_on(_THIS_IP_);
+		raw_local_irq_enable();
+
+		start_critical_timings();
+		trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id());
+	}
+}
+
+static int call_cpuidle_s2idle(struct cpuidle_driver *drv,
+			       struct cpuidle_device *dev)
+{
+	if (current_clr_polling_and_test())
+		return -EBUSY;
+
+	return cpuidle_enter_s2idle(drv, dev);
+}
+
+static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
+		      int next_state)
+{
+	/*
+	 * The idle task must be scheduled, it is pointless to go to idle, just
+	 * update no idle residency and return.
+	 */
+	if (current_clr_polling_and_test()) {
+		dev->last_residency_ns = 0;
+		local_irq_enable();
+		return -EBUSY;
+	}
+
+	/*
+	 * Enter the idle state previously returned by the governor decision.
+	 * This function will block until an interrupt occurs and will take
+	 * care of re-enabling the local interrupts
+	 */
+	return cpuidle_enter(drv, dev, next_state);
+}
+
+/**
+ * cpuidle_idle_call - the main idle function
+ *
+ * NOTE: no locks or semaphores should be used here
+ *
+ * On architectures that support TIF_POLLING_NRFLAG, is called with polling
+ * set, and it returns with polling set.  If it ever stops polling, it
+ * must clear the polling bit.
+ */
+static void cpuidle_idle_call(void)
+{
+	struct cpuidle_device *dev = cpuidle_get_device();
+	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+	int next_state, entered_state;
+
+	/*
+	 * Check if the idle task must be rescheduled. If it is the
+	 * case, exit the function after re-enabling the local irq.
+	 */
+	if (need_resched()) {
+		local_irq_enable();
+		return;
+	}
+
+	/*
+	 * The RCU framework needs to be told that we are entering an idle
+	 * section, so no more rcu read side critical sections and one more
+	 * step to the grace period
+	 */
+
+	if (cpuidle_not_available(drv, dev)) {
+		tick_nohz_idle_stop_tick();
+
+		default_idle_call();
+		goto exit_idle;
+	}
+
+	/*
+	 * Suspend-to-idle ("s2idle") is a system state in which all user space
+	 * has been frozen, all I/O devices have been suspended and the only
+	 * activity happens here and in interrupts (if any). In that case bypass
+	 * the cpuidle governor and go straight for the deepest idle state
+	 * available.  Possibly also suspend the local tick and the entire
+	 * timekeeping to prevent timer interrupts from kicking us out of idle
+	 * until a proper wakeup interrupt happens.
+	 */
+
+	if (idle_should_enter_s2idle() || dev->forced_idle_latency_limit_ns) {
+		u64 max_latency_ns;
+
+		if (idle_should_enter_s2idle()) {
+
+			entered_state = call_cpuidle_s2idle(drv, dev);
+			if (entered_state > 0)
+				goto exit_idle;
+
+			max_latency_ns = U64_MAX;
+		} else {
+			max_latency_ns = dev->forced_idle_latency_limit_ns;
+		}
+
+		tick_nohz_idle_stop_tick();
+
+		next_state = cpuidle_find_deepest_state(drv, dev, max_latency_ns);
+		call_cpuidle(drv, dev, next_state);
+	} else {
+		bool stop_tick = true;
+
+		/*
+		 * Ask the cpuidle framework to choose a convenient idle state.
+		 */
+		next_state = cpuidle_select(drv, dev, &stop_tick);
+
+		if (stop_tick || tick_nohz_tick_stopped())
+			tick_nohz_idle_stop_tick();
+		else
+			tick_nohz_idle_retain_tick();
+
+		entered_state = call_cpuidle(drv, dev, next_state);
+		/*
+		 * Give the governor an opportunity to reflect on the outcome
+		 */
+		cpuidle_reflect(dev, entered_state);
+	}
+
+exit_idle:
+	__current_set_polling();
+
+	/*
+	 * It is up to the idle functions to reenable local interrupts
+	 */
+	if (WARN_ON_ONCE(irqs_disabled()))
+		local_irq_enable();
+}
+
+/*
+ * Generic idle loop implementation
+ *
+ * Called with polling cleared.
+ */
+static void do_idle(void)
+{
+	int cpu = smp_processor_id();
+
+	/*
+	 * Check if we need to update blocked load
+	 */
+	nohz_run_idle_balance(cpu);
+
+	/*
+	 * If the arch has a polling bit, we maintain an invariant:
+	 *
+	 * Our polling bit is clear if we're not scheduled (i.e. if rq->curr !=
+	 * rq->idle). This means that, if rq->idle has the polling bit set,
+	 * then setting need_resched is guaranteed to cause the CPU to
+	 * reschedule.
+	 */
+
+	__current_set_polling();
+	tick_nohz_idle_enter();
+
+	while (!need_resched()) {
+		rmb();
+
+		local_irq_disable();
+
+		if (cpu_is_offline(cpu)) {
+			tick_nohz_idle_stop_tick();
+			cpuhp_report_idle_dead();
+			arch_cpu_idle_dead();
+		}
+
+		arch_cpu_idle_enter();
+		rcu_nocb_flush_deferred_wakeup();
+
+		/*
+		 * In poll mode we reenable interrupts and spin. Also if we
+		 * detected in the wakeup from idle path that the tick
+		 * broadcast device expired for us, we don't want to go deep
+		 * idle as we know that the IPI is going to arrive right away.
+		 */
+		if (cpu_idle_force_poll || tick_check_broadcast_expired()) {
+			tick_nohz_idle_restart_tick();
+			cpu_idle_poll();
+		} else {
+			cpuidle_idle_call();
+		}
+		arch_cpu_idle_exit();
+	}
+
+	/*
+	 * Since we fell out of the loop above, we know TIF_NEED_RESCHED must
+	 * be set, propagate it into PREEMPT_NEED_RESCHED.
+	 *
+	 * This is required because for polling idle loops we will not have had
+	 * an IPI to fold the state for us.
+	 */
+	preempt_set_need_resched();
+	tick_nohz_idle_exit();
+	__current_clr_polling();
+
+	/*
+	 * We promise to call sched_ttwu_pending() and reschedule if
+	 * need_resched() is set while polling is set. That means that clearing
+	 * polling needs to be visible before doing these things.
+	 */
+	smp_mb__after_atomic();
+
+	/*
+	 * RCU relies on this call to be done outside of an RCU read-side
+	 * critical section.
+	 */
+	flush_smp_call_function_queue();
+	schedule_idle();
+
+	if (unlikely(klp_patch_pending(current)))
+		klp_update_patch_state(current);
+}
+
+bool cpu_in_idle(unsigned long pc)
+{
+	return pc >= (unsigned long)__cpuidle_text_start &&
+		pc < (unsigned long)__cpuidle_text_end;
+}
+
+struct idle_timer {
+	struct hrtimer timer;
+	int done;
+};
+
+static enum hrtimer_restart idle_inject_timer_fn(struct hrtimer *timer)
+{
+	struct idle_timer *it = container_of(timer, struct idle_timer, timer);
+
+	WRITE_ONCE(it->done, 1);
+	set_tsk_need_resched(current);
+
+	return HRTIMER_NORESTART;
+}
+
+void play_idle_precise(u64 duration_ns, u64 latency_ns)
+{
+	struct idle_timer it;
+
+	/*
+	 * Only FIFO tasks can disable the tick since they don't need the forced
+	 * preemption.
+	 */
+	WARN_ON_ONCE(current->policy != SCHED_FIFO);
+	WARN_ON_ONCE(current->nr_cpus_allowed != 1);
+	WARN_ON_ONCE(!(current->flags & PF_KTHREAD));
+	WARN_ON_ONCE(!(current->flags & PF_NO_SETAFFINITY));
+	WARN_ON_ONCE(!duration_ns);
+	WARN_ON_ONCE(current->mm);
+
+	rcu_sleep_check();
+	preempt_disable();
+	current->flags |= PF_IDLE;
+	cpuidle_use_deepest_state(latency_ns);
+
+	it.done = 0;
+	hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	it.timer.function = idle_inject_timer_fn;
+	hrtimer_start(&it.timer, ns_to_ktime(duration_ns),
+		      HRTIMER_MODE_REL_PINNED_HARD);
+
+	while (!READ_ONCE(it.done))
+		do_idle();
+
+	cpuidle_use_deepest_state(0);
+	current->flags &= ~PF_IDLE;
+
+	preempt_fold_need_resched();
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(play_idle_precise);
+
+void cpu_startup_entry(enum cpuhp_state state)
+{
+	current->flags |= PF_IDLE;
+	arch_cpu_idle_prepare();
+	cpuhp_online_idle(state);
+	while (1)
+		do_idle();
+}
+
+/*
+ * idle-task scheduling class.
+ */
+
+#ifdef CONFIG_SMP
+static int
+select_task_rq_idle(struct task_struct *p, int cpu, int flags)
+{
+	return task_cpu(p); /* IDLE tasks as never migrated */
+}
+
+static int
+balance_idle(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	return WARN_ON_ONCE(1);
+}
+#endif
+
+/*
+ * Idle tasks are unconditionally rescheduled:
+ */
+static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int flags)
+{
+	resched_curr(rq);
+}
+
+static void put_prev_task_idle(struct rq *rq, struct task_struct *prev)
+{
+}
+
+static void set_next_task_idle(struct rq *rq, struct task_struct *next, bool first)
+{
+	update_idle_core(rq);
+	schedstat_inc(rq->sched_goidle);
+}
+
+#ifdef CONFIG_SMP
+static struct task_struct *pick_task_idle(struct rq *rq)
+{
+	return rq->idle;
+}
+#endif
+
+struct task_struct *pick_next_task_idle(struct rq *rq)
+{
+	struct task_struct *next = rq->idle;
+
+	set_next_task_idle(rq, next, true);
+
+	return next;
+}
+
+/*
+ * It is not legal to sleep in the idle task - print a warning
+ * message if some code attempts to do it:
+ */
+static void
+dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags)
+{
+	raw_spin_rq_unlock_irq(rq);
+	printk(KERN_ERR "bad: scheduling from the idle thread!\n");
+	dump_stack();
+	raw_spin_rq_lock_irq(rq);
+}
+
+/*
+ * scheduler tick hitting a task of our scheduling class.
+ *
+ * NOTE: This function can be called remotely by the tick offload that
+ * goes along full dynticks. Therefore no local assumption can be made
+ * and everything must be accessed through the @rq and @curr passed in
+ * parameters.
+ */
+static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued)
+{
+}
+
+static void switched_to_idle(struct rq *rq, struct task_struct *p)
+{
+	BUG();
+}
+
+static void
+prio_changed_idle(struct rq *rq, struct task_struct *p, int oldprio)
+{
+	BUG();
+}
+
+static void update_curr_idle(struct rq *rq)
+{
+}
+
+/*
+ * Simple, special scheduling class for the per-CPU idle tasks:
+ */
+DEFINE_SCHED_CLASS(idle) = {
+
+	/* no enqueue/yield_task for idle tasks */
+
+	/* dequeue is not valid, we print a debug message there: */
+	.dequeue_task		= dequeue_task_idle,
+
+	.check_preempt_curr	= check_preempt_curr_idle,
+
+	.pick_next_task		= pick_next_task_idle,
+	.put_prev_task		= put_prev_task_idle,
+	.set_next_task          = set_next_task_idle,
+
+#ifdef CONFIG_SMP
+	.balance		= balance_idle,
+	.pick_task		= pick_task_idle,
+	.select_task_rq		= select_task_rq_idle,
+	.set_cpus_allowed	= set_cpus_allowed_common,
+#endif
+
+	.task_tick		= task_tick_idle,
+
+	.prio_changed		= prio_changed_idle,
+	.switched_to		= switched_to_idle,
+	.update_curr		= update_curr_idle,
+};
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
new file mode 100644
index 000000000..373d42c70
--- /dev/null
+++ b/kernel/sched/isolation.c
@@ -0,0 +1,241 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Housekeeping management. Manage the targets for routine code that can run on
+ *  any CPU: unbound workqueues, timers, kthreads and any offloadable work.
+ *
+ * Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker
+ * Copyright (C) 2017-2018 SUSE, Frederic Weisbecker
+ *
+ */
+
+enum hk_flags {
+	HK_FLAG_TIMER		= BIT(HK_TYPE_TIMER),
+	HK_FLAG_RCU		= BIT(HK_TYPE_RCU),
+	HK_FLAG_MISC		= BIT(HK_TYPE_MISC),
+	HK_FLAG_SCHED		= BIT(HK_TYPE_SCHED),
+	HK_FLAG_TICK		= BIT(HK_TYPE_TICK),
+	HK_FLAG_DOMAIN		= BIT(HK_TYPE_DOMAIN),
+	HK_FLAG_WQ		= BIT(HK_TYPE_WQ),
+	HK_FLAG_MANAGED_IRQ	= BIT(HK_TYPE_MANAGED_IRQ),
+	HK_FLAG_KTHREAD		= BIT(HK_TYPE_KTHREAD),
+};
+
+DEFINE_STATIC_KEY_FALSE(housekeeping_overridden);
+EXPORT_SYMBOL_GPL(housekeeping_overridden);
+
+struct housekeeping {
+	cpumask_var_t cpumasks[HK_TYPE_MAX];
+	unsigned long flags;
+};
+
+static struct housekeeping housekeeping;
+
+bool housekeeping_enabled(enum hk_type type)
+{
+	return !!(housekeeping.flags & BIT(type));
+}
+EXPORT_SYMBOL_GPL(housekeeping_enabled);
+
+int housekeeping_any_cpu(enum hk_type type)
+{
+	int cpu;
+
+	if (static_branch_unlikely(&housekeeping_overridden)) {
+		if (housekeeping.flags & BIT(type)) {
+			cpu = sched_numa_find_closest(housekeeping.cpumasks[type], smp_processor_id());
+			if (cpu < nr_cpu_ids)
+				return cpu;
+
+			return cpumask_any_and(housekeeping.cpumasks[type], cpu_online_mask);
+		}
+	}
+	return smp_processor_id();
+}
+EXPORT_SYMBOL_GPL(housekeeping_any_cpu);
+
+const struct cpumask *housekeeping_cpumask(enum hk_type type)
+{
+	if (static_branch_unlikely(&housekeeping_overridden))
+		if (housekeeping.flags & BIT(type))
+			return housekeeping.cpumasks[type];
+	return cpu_possible_mask;
+}
+EXPORT_SYMBOL_GPL(housekeeping_cpumask);
+
+void housekeeping_affine(struct task_struct *t, enum hk_type type)
+{
+	if (static_branch_unlikely(&housekeeping_overridden))
+		if (housekeeping.flags & BIT(type))
+			set_cpus_allowed_ptr(t, housekeeping.cpumasks[type]);
+}
+EXPORT_SYMBOL_GPL(housekeeping_affine);
+
+bool housekeeping_test_cpu(int cpu, enum hk_type type)
+{
+	if (static_branch_unlikely(&housekeeping_overridden))
+		if (housekeeping.flags & BIT(type))
+			return cpumask_test_cpu(cpu, housekeeping.cpumasks[type]);
+	return true;
+}
+EXPORT_SYMBOL_GPL(housekeeping_test_cpu);
+
+void __init housekeeping_init(void)
+{
+	enum hk_type type;
+
+	if (!housekeeping.flags)
+		return;
+
+	static_branch_enable(&housekeeping_overridden);
+
+	if (housekeeping.flags & HK_FLAG_TICK)
+		sched_tick_offload_init();
+
+	for_each_set_bit(type, &housekeeping.flags, HK_TYPE_MAX) {
+		/* We need at least one CPU to handle housekeeping work */
+		WARN_ON_ONCE(cpumask_empty(housekeeping.cpumasks[type]));
+	}
+}
+
+static void __init housekeeping_setup_type(enum hk_type type,
+					   cpumask_var_t housekeeping_staging)
+{
+
+	alloc_bootmem_cpumask_var(&housekeeping.cpumasks[type]);
+	cpumask_copy(housekeeping.cpumasks[type],
+		     housekeeping_staging);
+}
+
+static int __init housekeeping_setup(char *str, unsigned long flags)
+{
+	cpumask_var_t non_housekeeping_mask, housekeeping_staging;
+	int err = 0;
+
+	if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK)) {
+		if (!IS_ENABLED(CONFIG_NO_HZ_FULL)) {
+			pr_warn("Housekeeping: nohz unsupported."
+				" Build with CONFIG_NO_HZ_FULL\n");
+			return 0;
+		}
+	}
+
+	alloc_bootmem_cpumask_var(&non_housekeeping_mask);
+	if (cpulist_parse(str, non_housekeeping_mask) < 0) {
+		pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n");
+		goto free_non_housekeeping_mask;
+	}
+
+	alloc_bootmem_cpumask_var(&housekeeping_staging);
+	cpumask_andnot(housekeeping_staging,
+		       cpu_possible_mask, non_housekeeping_mask);
+
+	if (!cpumask_intersects(cpu_present_mask, housekeeping_staging)) {
+		__cpumask_set_cpu(smp_processor_id(), housekeeping_staging);
+		__cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask);
+		if (!housekeeping.flags) {
+			pr_warn("Housekeeping: must include one present CPU, "
+				"using boot CPU:%d\n", smp_processor_id());
+		}
+	}
+
+	if (!housekeeping.flags) {
+		/* First setup call ("nohz_full=" or "isolcpus=") */
+		enum hk_type type;
+
+		for_each_set_bit(type, &flags, HK_TYPE_MAX)
+			housekeeping_setup_type(type, housekeeping_staging);
+	} else {
+		/* Second setup call ("nohz_full=" after "isolcpus=" or the reverse) */
+		enum hk_type type;
+		unsigned long iter_flags = flags & housekeeping.flags;
+
+		for_each_set_bit(type, &iter_flags, HK_TYPE_MAX) {
+			if (!cpumask_equal(housekeeping_staging,
+					   housekeeping.cpumasks[type])) {
+				pr_warn("Housekeeping: nohz_full= must match isolcpus=\n");
+				goto free_housekeeping_staging;
+			}
+		}
+
+		iter_flags = flags & ~housekeeping.flags;
+
+		for_each_set_bit(type, &iter_flags, HK_TYPE_MAX)
+			housekeeping_setup_type(type, housekeeping_staging);
+	}
+
+	if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK))
+		tick_nohz_full_setup(non_housekeeping_mask);
+
+	housekeeping.flags |= flags;
+	err = 1;
+
+free_housekeeping_staging:
+	free_bootmem_cpumask_var(housekeeping_staging);
+free_non_housekeeping_mask:
+	free_bootmem_cpumask_var(non_housekeeping_mask);
+
+	return err;
+}
+
+static int __init housekeeping_nohz_full_setup(char *str)
+{
+	unsigned long flags;
+
+	flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU |
+		HK_FLAG_MISC | HK_FLAG_KTHREAD;
+
+	return housekeeping_setup(str, flags);
+}
+__setup("nohz_full=", housekeeping_nohz_full_setup);
+
+static int __init housekeeping_isolcpus_setup(char *str)
+{
+	unsigned long flags = 0;
+	bool illegal = false;
+	char *par;
+	int len;
+
+	while (isalpha(*str)) {
+		if (!strncmp(str, "nohz,", 5)) {
+			str += 5;
+			flags |= HK_FLAG_TICK;
+			continue;
+		}
+
+		if (!strncmp(str, "domain,", 7)) {
+			str += 7;
+			flags |= HK_FLAG_DOMAIN;
+			continue;
+		}
+
+		if (!strncmp(str, "managed_irq,", 12)) {
+			str += 12;
+			flags |= HK_FLAG_MANAGED_IRQ;
+			continue;
+		}
+
+		/*
+		 * Skip unknown sub-parameter and validate that it is not
+		 * containing an invalid character.
+		 */
+		for (par = str, len = 0; *str && *str != ','; str++, len++) {
+			if (!isalpha(*str) && *str != '_')
+				illegal = true;
+		}
+
+		if (illegal) {
+			pr_warn("isolcpus: Invalid flag %.*s\n", len, par);
+			return 0;
+		}
+
+		pr_info("isolcpus: Skipped unknown flag %.*s\n", len, par);
+		str++;
+	}
+
+	/* Default behaviour for isolcpus without flags */
+	if (!flags)
+		flags |= HK_FLAG_DOMAIN;
+
+	return housekeeping_setup(str, flags);
+}
+__setup("isolcpus=", housekeeping_isolcpus_setup);
diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c
new file mode 100644
index 000000000..52c8f8226
--- /dev/null
+++ b/kernel/sched/loadavg.c
@@ -0,0 +1,397 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kernel/sched/loadavg.c
+ *
+ * This file contains the magic bits required to compute the global loadavg
+ * figure. Its a silly number but people think its important. We go through
+ * great pains to make it work on big machines and tickless kernels.
+ */
+
+/*
+ * Global load-average calculations
+ *
+ * We take a distributed and async approach to calculating the global load-avg
+ * in order to minimize overhead.
+ *
+ * The global load average is an exponentially decaying average of nr_running +
+ * nr_uninterruptible.
+ *
+ * Once every LOAD_FREQ:
+ *
+ *   nr_active = 0;
+ *   for_each_possible_cpu(cpu)
+ *	nr_active += cpu_of(cpu)->nr_running + cpu_of(cpu)->nr_uninterruptible;
+ *
+ *   avenrun[n] = avenrun[0] * exp_n + nr_active * (1 - exp_n)
+ *
+ * Due to a number of reasons the above turns in the mess below:
+ *
+ *  - for_each_possible_cpu() is prohibitively expensive on machines with
+ *    serious number of CPUs, therefore we need to take a distributed approach
+ *    to calculating nr_active.
+ *
+ *        \Sum_i x_i(t) = \Sum_i x_i(t) - x_i(t_0) | x_i(t_0) := 0
+ *                      = \Sum_i { \Sum_j=1 x_i(t_j) - x_i(t_j-1) }
+ *
+ *    So assuming nr_active := 0 when we start out -- true per definition, we
+ *    can simply take per-CPU deltas and fold those into a global accumulate
+ *    to obtain the same result. See calc_load_fold_active().
+ *
+ *    Furthermore, in order to avoid synchronizing all per-CPU delta folding
+ *    across the machine, we assume 10 ticks is sufficient time for every
+ *    CPU to have completed this task.
+ *
+ *    This places an upper-bound on the IRQ-off latency of the machine. Then
+ *    again, being late doesn't loose the delta, just wrecks the sample.
+ *
+ *  - cpu_rq()->nr_uninterruptible isn't accurately tracked per-CPU because
+ *    this would add another cross-CPU cacheline miss and atomic operation
+ *    to the wakeup path. Instead we increment on whatever CPU the task ran
+ *    when it went into uninterruptible state and decrement on whatever CPU
+ *    did the wakeup. This means that only the sum of nr_uninterruptible over
+ *    all CPUs yields the correct result.
+ *
+ *  This covers the NO_HZ=n code, for extra head-aches, see the comment below.
+ */
+
+/* Variables and functions for calc_load */
+atomic_long_t calc_load_tasks;
+unsigned long calc_load_update;
+unsigned long avenrun[3];
+EXPORT_SYMBOL(avenrun); /* should be removed */
+
+/**
+ * get_avenrun - get the load average array
+ * @loads:	pointer to dest load array
+ * @offset:	offset to add
+ * @shift:	shift count to shift the result left
+ *
+ * These values are estimates at best, so no need for locking.
+ */
+void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
+{
+	loads[0] = (avenrun[0] + offset) << shift;
+	loads[1] = (avenrun[1] + offset) << shift;
+	loads[2] = (avenrun[2] + offset) << shift;
+}
+
+long calc_load_fold_active(struct rq *this_rq, long adjust)
+{
+	long nr_active, delta = 0;
+
+	nr_active = this_rq->nr_running - adjust;
+	nr_active += (int)this_rq->nr_uninterruptible;
+
+	if (nr_active != this_rq->calc_load_active) {
+		delta = nr_active - this_rq->calc_load_active;
+		this_rq->calc_load_active = nr_active;
+	}
+
+	return delta;
+}
+
+/**
+ * fixed_power_int - compute: x^n, in O(log n) time
+ *
+ * @x:         base of the power
+ * @frac_bits: fractional bits of @x
+ * @n:         power to raise @x to.
+ *
+ * By exploiting the relation between the definition of the natural power
+ * function: x^n := x*x*...*x (x multiplied by itself for n times), and
+ * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
+ * (where: n_i \elem {0, 1}, the binary vector representing n),
+ * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
+ * of course trivially computable in O(log_2 n), the length of our binary
+ * vector.
+ */
+static unsigned long
+fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n)
+{
+	unsigned long result = 1UL << frac_bits;
+
+	if (n) {
+		for (;;) {
+			if (n & 1) {
+				result *= x;
+				result += 1UL << (frac_bits - 1);
+				result >>= frac_bits;
+			}
+			n >>= 1;
+			if (!n)
+				break;
+			x *= x;
+			x += 1UL << (frac_bits - 1);
+			x >>= frac_bits;
+		}
+	}
+
+	return result;
+}
+
+/*
+ * a1 = a0 * e + a * (1 - e)
+ *
+ * a2 = a1 * e + a * (1 - e)
+ *    = (a0 * e + a * (1 - e)) * e + a * (1 - e)
+ *    = a0 * e^2 + a * (1 - e) * (1 + e)
+ *
+ * a3 = a2 * e + a * (1 - e)
+ *    = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
+ *    = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
+ *
+ *  ...
+ *
+ * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
+ *    = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
+ *    = a0 * e^n + a * (1 - e^n)
+ *
+ * [1] application of the geometric series:
+ *
+ *              n         1 - x^(n+1)
+ *     S_n := \Sum x^i = -------------
+ *             i=0          1 - x
+ */
+unsigned long
+calc_load_n(unsigned long load, unsigned long exp,
+	    unsigned long active, unsigned int n)
+{
+	return calc_load(load, fixed_power_int(exp, FSHIFT, n), active);
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+/*
+ * Handle NO_HZ for the global load-average.
+ *
+ * Since the above described distributed algorithm to compute the global
+ * load-average relies on per-CPU sampling from the tick, it is affected by
+ * NO_HZ.
+ *
+ * The basic idea is to fold the nr_active delta into a global NO_HZ-delta upon
+ * entering NO_HZ state such that we can include this as an 'extra' CPU delta
+ * when we read the global state.
+ *
+ * Obviously reality has to ruin such a delightfully simple scheme:
+ *
+ *  - When we go NO_HZ idle during the window, we can negate our sample
+ *    contribution, causing under-accounting.
+ *
+ *    We avoid this by keeping two NO_HZ-delta counters and flipping them
+ *    when the window starts, thus separating old and new NO_HZ load.
+ *
+ *    The only trick is the slight shift in index flip for read vs write.
+ *
+ *        0s            5s            10s           15s
+ *          +10           +10           +10           +10
+ *        |-|-----------|-|-----------|-|-----------|-|
+ *    r:0 0 1           1 0           0 1           1 0
+ *    w:0 1 1           0 0           1 1           0 0
+ *
+ *    This ensures we'll fold the old NO_HZ contribution in this window while
+ *    accumulating the new one.
+ *
+ *  - When we wake up from NO_HZ during the window, we push up our
+ *    contribution, since we effectively move our sample point to a known
+ *    busy state.
+ *
+ *    This is solved by pushing the window forward, and thus skipping the
+ *    sample, for this CPU (effectively using the NO_HZ-delta for this CPU which
+ *    was in effect at the time the window opened). This also solves the issue
+ *    of having to deal with a CPU having been in NO_HZ for multiple LOAD_FREQ
+ *    intervals.
+ *
+ * When making the ILB scale, we should try to pull this in as well.
+ */
+static atomic_long_t calc_load_nohz[2];
+static int calc_load_idx;
+
+static inline int calc_load_write_idx(void)
+{
+	int idx = calc_load_idx;
+
+	/*
+	 * See calc_global_nohz(), if we observe the new index, we also
+	 * need to observe the new update time.
+	 */
+	smp_rmb();
+
+	/*
+	 * If the folding window started, make sure we start writing in the
+	 * next NO_HZ-delta.
+	 */
+	if (!time_before(jiffies, READ_ONCE(calc_load_update)))
+		idx++;
+
+	return idx & 1;
+}
+
+static inline int calc_load_read_idx(void)
+{
+	return calc_load_idx & 1;
+}
+
+static void calc_load_nohz_fold(struct rq *rq)
+{
+	long delta;
+
+	delta = calc_load_fold_active(rq, 0);
+	if (delta) {
+		int idx = calc_load_write_idx();
+
+		atomic_long_add(delta, &calc_load_nohz[idx]);
+	}
+}
+
+void calc_load_nohz_start(void)
+{
+	/*
+	 * We're going into NO_HZ mode, if there's any pending delta, fold it
+	 * into the pending NO_HZ delta.
+	 */
+	calc_load_nohz_fold(this_rq());
+}
+
+/*
+ * Keep track of the load for NOHZ_FULL, must be called between
+ * calc_load_nohz_{start,stop}().
+ */
+void calc_load_nohz_remote(struct rq *rq)
+{
+	calc_load_nohz_fold(rq);
+}
+
+void calc_load_nohz_stop(void)
+{
+	struct rq *this_rq = this_rq();
+
+	/*
+	 * If we're still before the pending sample window, we're done.
+	 */
+	this_rq->calc_load_update = READ_ONCE(calc_load_update);
+	if (time_before(jiffies, this_rq->calc_load_update))
+		return;
+
+	/*
+	 * We woke inside or after the sample window, this means we're already
+	 * accounted through the nohz accounting, so skip the entire deal and
+	 * sync up for the next window.
+	 */
+	if (time_before(jiffies, this_rq->calc_load_update + 10))
+		this_rq->calc_load_update += LOAD_FREQ;
+}
+
+static long calc_load_nohz_read(void)
+{
+	int idx = calc_load_read_idx();
+	long delta = 0;
+
+	if (atomic_long_read(&calc_load_nohz[idx]))
+		delta = atomic_long_xchg(&calc_load_nohz[idx], 0);
+
+	return delta;
+}
+
+/*
+ * NO_HZ can leave us missing all per-CPU ticks calling
+ * calc_load_fold_active(), but since a NO_HZ CPU folds its delta into
+ * calc_load_nohz per calc_load_nohz_start(), all we need to do is fold
+ * in the pending NO_HZ delta if our NO_HZ period crossed a load cycle boundary.
+ *
+ * Once we've updated the global active value, we need to apply the exponential
+ * weights adjusted to the number of cycles missed.
+ */
+static void calc_global_nohz(void)
+{
+	unsigned long sample_window;
+	long delta, active, n;
+
+	sample_window = READ_ONCE(calc_load_update);
+	if (!time_before(jiffies, sample_window + 10)) {
+		/*
+		 * Catch-up, fold however many we are behind still
+		 */
+		delta = jiffies - sample_window - 10;
+		n = 1 + (delta / LOAD_FREQ);
+
+		active = atomic_long_read(&calc_load_tasks);
+		active = active > 0 ? active * FIXED_1 : 0;
+
+		avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n);
+		avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n);
+		avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n);
+
+		WRITE_ONCE(calc_load_update, sample_window + n * LOAD_FREQ);
+	}
+
+	/*
+	 * Flip the NO_HZ index...
+	 *
+	 * Make sure we first write the new time then flip the index, so that
+	 * calc_load_write_idx() will see the new time when it reads the new
+	 * index, this avoids a double flip messing things up.
+	 */
+	smp_wmb();
+	calc_load_idx++;
+}
+#else /* !CONFIG_NO_HZ_COMMON */
+
+static inline long calc_load_nohz_read(void) { return 0; }
+static inline void calc_global_nohz(void) { }
+
+#endif /* CONFIG_NO_HZ_COMMON */
+
+/*
+ * calc_load - update the avenrun load estimates 10 ticks after the
+ * CPUs have updated calc_load_tasks.
+ *
+ * Called from the global timer code.
+ */
+void calc_global_load(void)
+{
+	unsigned long sample_window;
+	long active, delta;
+
+	sample_window = READ_ONCE(calc_load_update);
+	if (time_before(jiffies, sample_window + 10))
+		return;
+
+	/*
+	 * Fold the 'old' NO_HZ-delta to include all NO_HZ CPUs.
+	 */
+	delta = calc_load_nohz_read();
+	if (delta)
+		atomic_long_add(delta, &calc_load_tasks);
+
+	active = atomic_long_read(&calc_load_tasks);
+	active = active > 0 ? active * FIXED_1 : 0;
+
+	avenrun[0] = calc_load(avenrun[0], EXP_1, active);
+	avenrun[1] = calc_load(avenrun[1], EXP_5, active);
+	avenrun[2] = calc_load(avenrun[2], EXP_15, active);
+
+	WRITE_ONCE(calc_load_update, sample_window + LOAD_FREQ);
+
+	/*
+	 * In case we went to NO_HZ for multiple LOAD_FREQ intervals
+	 * catch up in bulk.
+	 */
+	calc_global_nohz();
+}
+
+/*
+ * Called from scheduler_tick() to periodically update this CPU's
+ * active count.
+ */
+void calc_global_load_tick(struct rq *this_rq)
+{
+	long delta;
+
+	if (time_before(jiffies, this_rq->calc_load_update))
+		return;
+
+	delta  = calc_load_fold_active(this_rq, 0);
+	if (delta)
+		atomic_long_add(delta, &calc_load_tasks);
+
+	this_rq->calc_load_update += LOAD_FREQ;
+}
diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c
new file mode 100644
index 000000000..0c5be7ebb
--- /dev/null
+++ b/kernel/sched/membarrier.c
@@ -0,0 +1,629 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2010-2017 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * membarrier system call
+ */
+
+/*
+ * For documentation purposes, here are some membarrier ordering
+ * scenarios to keep in mind:
+ *
+ * A) Userspace thread execution after IPI vs membarrier's memory
+ *    barrier before sending the IPI
+ *
+ * Userspace variables:
+ *
+ * int x = 0, y = 0;
+ *
+ * The memory barrier at the start of membarrier() on CPU0 is necessary in
+ * order to enforce the guarantee that any writes occurring on CPU0 before
+ * the membarrier() is executed will be visible to any code executing on
+ * CPU1 after the IPI-induced memory barrier:
+ *
+ *         CPU0                              CPU1
+ *
+ *         x = 1
+ *         membarrier():
+ *           a: smp_mb()
+ *           b: send IPI                       IPI-induced mb
+ *           c: smp_mb()
+ *         r2 = y
+ *                                           y = 1
+ *                                           barrier()
+ *                                           r1 = x
+ *
+ *                     BUG_ON(r1 == 0 && r2 == 0)
+ *
+ * The write to y and load from x by CPU1 are unordered by the hardware,
+ * so it's possible to have "r1 = x" reordered before "y = 1" at any
+ * point after (b).  If the memory barrier at (a) is omitted, then "x = 1"
+ * can be reordered after (a) (although not after (c)), so we get r1 == 0
+ * and r2 == 0.  This violates the guarantee that membarrier() is
+ * supposed by provide.
+ *
+ * The timing of the memory barrier at (a) has to ensure that it executes
+ * before the IPI-induced memory barrier on CPU1.
+ *
+ * B) Userspace thread execution before IPI vs membarrier's memory
+ *    barrier after completing the IPI
+ *
+ * Userspace variables:
+ *
+ * int x = 0, y = 0;
+ *
+ * The memory barrier at the end of membarrier() on CPU0 is necessary in
+ * order to enforce the guarantee that any writes occurring on CPU1 before
+ * the membarrier() is executed will be visible to any code executing on
+ * CPU0 after the membarrier():
+ *
+ *         CPU0                              CPU1
+ *
+ *                                           x = 1
+ *                                           barrier()
+ *                                           y = 1
+ *         r2 = y
+ *         membarrier():
+ *           a: smp_mb()
+ *           b: send IPI                       IPI-induced mb
+ *           c: smp_mb()
+ *         r1 = x
+ *         BUG_ON(r1 == 0 && r2 == 1)
+ *
+ * The writes to x and y are unordered by the hardware, so it's possible to
+ * have "r2 = 1" even though the write to x doesn't execute until (b).  If
+ * the memory barrier at (c) is omitted then "r1 = x" can be reordered
+ * before (b) (although not before (a)), so we get "r1 = 0".  This violates
+ * the guarantee that membarrier() is supposed to provide.
+ *
+ * The timing of the memory barrier at (c) has to ensure that it executes
+ * after the IPI-induced memory barrier on CPU1.
+ *
+ * C) Scheduling userspace thread -> kthread -> userspace thread vs membarrier
+ *
+ *           CPU0                            CPU1
+ *
+ *           membarrier():
+ *           a: smp_mb()
+ *                                           d: switch to kthread (includes mb)
+ *           b: read rq->curr->mm == NULL
+ *                                           e: switch to user (includes mb)
+ *           c: smp_mb()
+ *
+ * Using the scenario from (A), we can show that (a) needs to be paired
+ * with (e). Using the scenario from (B), we can show that (c) needs to
+ * be paired with (d).
+ *
+ * D) exit_mm vs membarrier
+ *
+ * Two thread groups are created, A and B.  Thread group B is created by
+ * issuing clone from group A with flag CLONE_VM set, but not CLONE_THREAD.
+ * Let's assume we have a single thread within each thread group (Thread A
+ * and Thread B).  Thread A runs on CPU0, Thread B runs on CPU1.
+ *
+ *           CPU0                            CPU1
+ *
+ *           membarrier():
+ *             a: smp_mb()
+ *                                           exit_mm():
+ *                                             d: smp_mb()
+ *                                             e: current->mm = NULL
+ *             b: read rq->curr->mm == NULL
+ *             c: smp_mb()
+ *
+ * Using scenario (B), we can show that (c) needs to be paired with (d).
+ *
+ * E) kthread_{use,unuse}_mm vs membarrier
+ *
+ *           CPU0                            CPU1
+ *
+ *           membarrier():
+ *           a: smp_mb()
+ *                                           kthread_unuse_mm()
+ *                                             d: smp_mb()
+ *                                             e: current->mm = NULL
+ *           b: read rq->curr->mm == NULL
+ *                                           kthread_use_mm()
+ *                                             f: current->mm = mm
+ *                                             g: smp_mb()
+ *           c: smp_mb()
+ *
+ * Using the scenario from (A), we can show that (a) needs to be paired
+ * with (g). Using the scenario from (B), we can show that (c) needs to
+ * be paired with (d).
+ */
+
+/*
+ * Bitmask made from a "or" of all commands within enum membarrier_cmd,
+ * except MEMBARRIER_CMD_QUERY.
+ */
+#ifdef CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE
+#define MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK			\
+	(MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE			\
+	| MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE)
+#else
+#define MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK	0
+#endif
+
+#ifdef CONFIG_RSEQ
+#define MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK		\
+	(MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ			\
+	| MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ)
+#else
+#define MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK	0
+#endif
+
+#define MEMBARRIER_CMD_BITMASK						\
+	(MEMBARRIER_CMD_GLOBAL | MEMBARRIER_CMD_GLOBAL_EXPEDITED	\
+	| MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED			\
+	| MEMBARRIER_CMD_PRIVATE_EXPEDITED				\
+	| MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED			\
+	| MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK		\
+	| MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK)
+
+static void ipi_mb(void *info)
+{
+	smp_mb();	/* IPIs should be serializing but paranoid. */
+}
+
+static void ipi_sync_core(void *info)
+{
+	/*
+	 * The smp_mb() in membarrier after all the IPIs is supposed to
+	 * ensure that memory on remote CPUs that occur before the IPI
+	 * become visible to membarrier()'s caller -- see scenario B in
+	 * the big comment at the top of this file.
+	 *
+	 * A sync_core() would provide this guarantee, but
+	 * sync_core_before_usermode() might end up being deferred until
+	 * after membarrier()'s smp_mb().
+	 */
+	smp_mb();	/* IPIs should be serializing but paranoid. */
+
+	sync_core_before_usermode();
+}
+
+static void ipi_rseq(void *info)
+{
+	/*
+	 * Ensure that all stores done by the calling thread are visible
+	 * to the current task before the current task resumes.  We could
+	 * probably optimize this away on most architectures, but by the
+	 * time we've already sent an IPI, the cost of the extra smp_mb()
+	 * is negligible.
+	 */
+	smp_mb();
+	rseq_preempt(current);
+}
+
+static void ipi_sync_rq_state(void *info)
+{
+	struct mm_struct *mm = (struct mm_struct *) info;
+
+	if (current->mm != mm)
+		return;
+	this_cpu_write(runqueues.membarrier_state,
+		       atomic_read(&mm->membarrier_state));
+	/*
+	 * Issue a memory barrier after setting
+	 * MEMBARRIER_STATE_GLOBAL_EXPEDITED in the current runqueue to
+	 * guarantee that no memory access following registration is reordered
+	 * before registration.
+	 */
+	smp_mb();
+}
+
+void membarrier_exec_mmap(struct mm_struct *mm)
+{
+	/*
+	 * Issue a memory barrier before clearing membarrier_state to
+	 * guarantee that no memory access prior to exec is reordered after
+	 * clearing this state.
+	 */
+	smp_mb();
+	atomic_set(&mm->membarrier_state, 0);
+	/*
+	 * Keep the runqueue membarrier_state in sync with this mm
+	 * membarrier_state.
+	 */
+	this_cpu_write(runqueues.membarrier_state, 0);
+}
+
+void membarrier_update_current_mm(struct mm_struct *next_mm)
+{
+	struct rq *rq = this_rq();
+	int membarrier_state = 0;
+
+	if (next_mm)
+		membarrier_state = atomic_read(&next_mm->membarrier_state);
+	if (READ_ONCE(rq->membarrier_state) == membarrier_state)
+		return;
+	WRITE_ONCE(rq->membarrier_state, membarrier_state);
+}
+
+static int membarrier_global_expedited(void)
+{
+	int cpu;
+	cpumask_var_t tmpmask;
+
+	if (num_online_cpus() == 1)
+		return 0;
+
+	/*
+	 * Matches memory barriers around rq->curr modification in
+	 * scheduler.
+	 */
+	smp_mb();	/* system call entry is not a mb. */
+
+	if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
+		return -ENOMEM;
+
+	cpus_read_lock();
+	rcu_read_lock();
+	for_each_online_cpu(cpu) {
+		struct task_struct *p;
+
+		/*
+		 * Skipping the current CPU is OK even through we can be
+		 * migrated at any point. The current CPU, at the point
+		 * where we read raw_smp_processor_id(), is ensured to
+		 * be in program order with respect to the caller
+		 * thread. Therefore, we can skip this CPU from the
+		 * iteration.
+		 */
+		if (cpu == raw_smp_processor_id())
+			continue;
+
+		if (!(READ_ONCE(cpu_rq(cpu)->membarrier_state) &
+		    MEMBARRIER_STATE_GLOBAL_EXPEDITED))
+			continue;
+
+		/*
+		 * Skip the CPU if it runs a kernel thread which is not using
+		 * a task mm.
+		 */
+		p = rcu_dereference(cpu_rq(cpu)->curr);
+		if (!p->mm)
+			continue;
+
+		__cpumask_set_cpu(cpu, tmpmask);
+	}
+	rcu_read_unlock();
+
+	preempt_disable();
+	smp_call_function_many(tmpmask, ipi_mb, NULL, 1);
+	preempt_enable();
+
+	free_cpumask_var(tmpmask);
+	cpus_read_unlock();
+
+	/*
+	 * Memory barrier on the caller thread _after_ we finished
+	 * waiting for the last IPI. Matches memory barriers around
+	 * rq->curr modification in scheduler.
+	 */
+	smp_mb();	/* exit from system call is not a mb */
+	return 0;
+}
+
+static int membarrier_private_expedited(int flags, int cpu_id)
+{
+	cpumask_var_t tmpmask;
+	struct mm_struct *mm = current->mm;
+	smp_call_func_t ipi_func = ipi_mb;
+
+	if (flags == MEMBARRIER_FLAG_SYNC_CORE) {
+		if (!IS_ENABLED(CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE))
+			return -EINVAL;
+		if (!(atomic_read(&mm->membarrier_state) &
+		      MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE_READY))
+			return -EPERM;
+		ipi_func = ipi_sync_core;
+	} else if (flags == MEMBARRIER_FLAG_RSEQ) {
+		if (!IS_ENABLED(CONFIG_RSEQ))
+			return -EINVAL;
+		if (!(atomic_read(&mm->membarrier_state) &
+		      MEMBARRIER_STATE_PRIVATE_EXPEDITED_RSEQ_READY))
+			return -EPERM;
+		ipi_func = ipi_rseq;
+	} else {
+		WARN_ON_ONCE(flags);
+		if (!(atomic_read(&mm->membarrier_state) &
+		      MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY))
+			return -EPERM;
+	}
+
+	if (flags != MEMBARRIER_FLAG_SYNC_CORE &&
+	    (atomic_read(&mm->mm_users) == 1 || num_online_cpus() == 1))
+		return 0;
+
+	/*
+	 * Matches memory barriers around rq->curr modification in
+	 * scheduler.
+	 */
+	smp_mb();	/* system call entry is not a mb. */
+
+	if (cpu_id < 0 && !zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
+		return -ENOMEM;
+
+	cpus_read_lock();
+
+	if (cpu_id >= 0) {
+		struct task_struct *p;
+
+		if (cpu_id >= nr_cpu_ids || !cpu_online(cpu_id))
+			goto out;
+		rcu_read_lock();
+		p = rcu_dereference(cpu_rq(cpu_id)->curr);
+		if (!p || p->mm != mm) {
+			rcu_read_unlock();
+			goto out;
+		}
+		rcu_read_unlock();
+	} else {
+		int cpu;
+
+		rcu_read_lock();
+		for_each_online_cpu(cpu) {
+			struct task_struct *p;
+
+			p = rcu_dereference(cpu_rq(cpu)->curr);
+			if (p && p->mm == mm)
+				__cpumask_set_cpu(cpu, tmpmask);
+		}
+		rcu_read_unlock();
+	}
+
+	if (cpu_id >= 0) {
+		/*
+		 * smp_call_function_single() will call ipi_func() if cpu_id
+		 * is the calling CPU.
+		 */
+		smp_call_function_single(cpu_id, ipi_func, NULL, 1);
+	} else {
+		/*
+		 * For regular membarrier, we can save a few cycles by
+		 * skipping the current cpu -- we're about to do smp_mb()
+		 * below, and if we migrate to a different cpu, this cpu
+		 * and the new cpu will execute a full barrier in the
+		 * scheduler.
+		 *
+		 * For SYNC_CORE, we do need a barrier on the current cpu --
+		 * otherwise, if we are migrated and replaced by a different
+		 * task in the same mm just before, during, or after
+		 * membarrier, we will end up with some thread in the mm
+		 * running without a core sync.
+		 *
+		 * For RSEQ, don't rseq_preempt() the caller.  User code
+		 * is not supposed to issue syscalls at all from inside an
+		 * rseq critical section.
+		 */
+		if (flags != MEMBARRIER_FLAG_SYNC_CORE) {
+			preempt_disable();
+			smp_call_function_many(tmpmask, ipi_func, NULL, true);
+			preempt_enable();
+		} else {
+			on_each_cpu_mask(tmpmask, ipi_func, NULL, true);
+		}
+	}
+
+out:
+	if (cpu_id < 0)
+		free_cpumask_var(tmpmask);
+	cpus_read_unlock();
+
+	/*
+	 * Memory barrier on the caller thread _after_ we finished
+	 * waiting for the last IPI. Matches memory barriers around
+	 * rq->curr modification in scheduler.
+	 */
+	smp_mb();	/* exit from system call is not a mb */
+
+	return 0;
+}
+
+static int sync_runqueues_membarrier_state(struct mm_struct *mm)
+{
+	int membarrier_state = atomic_read(&mm->membarrier_state);
+	cpumask_var_t tmpmask;
+	int cpu;
+
+	if (atomic_read(&mm->mm_users) == 1 || num_online_cpus() == 1) {
+		this_cpu_write(runqueues.membarrier_state, membarrier_state);
+
+		/*
+		 * For single mm user, we can simply issue a memory barrier
+		 * after setting MEMBARRIER_STATE_GLOBAL_EXPEDITED in the
+		 * mm and in the current runqueue to guarantee that no memory
+		 * access following registration is reordered before
+		 * registration.
+		 */
+		smp_mb();
+		return 0;
+	}
+
+	if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
+		return -ENOMEM;
+
+	/*
+	 * For mm with multiple users, we need to ensure all future
+	 * scheduler executions will observe @mm's new membarrier
+	 * state.
+	 */
+	synchronize_rcu();
+
+	/*
+	 * For each cpu runqueue, if the task's mm match @mm, ensure that all
+	 * @mm's membarrier state set bits are also set in the runqueue's
+	 * membarrier state. This ensures that a runqueue scheduling
+	 * between threads which are users of @mm has its membarrier state
+	 * updated.
+	 */
+	cpus_read_lock();
+	rcu_read_lock();
+	for_each_online_cpu(cpu) {
+		struct rq *rq = cpu_rq(cpu);
+		struct task_struct *p;
+
+		p = rcu_dereference(rq->curr);
+		if (p && p->mm == mm)
+			__cpumask_set_cpu(cpu, tmpmask);
+	}
+	rcu_read_unlock();
+
+	on_each_cpu_mask(tmpmask, ipi_sync_rq_state, mm, true);
+
+	free_cpumask_var(tmpmask);
+	cpus_read_unlock();
+
+	return 0;
+}
+
+static int membarrier_register_global_expedited(void)
+{
+	struct task_struct *p = current;
+	struct mm_struct *mm = p->mm;
+	int ret;
+
+	if (atomic_read(&mm->membarrier_state) &
+	    MEMBARRIER_STATE_GLOBAL_EXPEDITED_READY)
+		return 0;
+	atomic_or(MEMBARRIER_STATE_GLOBAL_EXPEDITED, &mm->membarrier_state);
+	ret = sync_runqueues_membarrier_state(mm);
+	if (ret)
+		return ret;
+	atomic_or(MEMBARRIER_STATE_GLOBAL_EXPEDITED_READY,
+		  &mm->membarrier_state);
+
+	return 0;
+}
+
+static int membarrier_register_private_expedited(int flags)
+{
+	struct task_struct *p = current;
+	struct mm_struct *mm = p->mm;
+	int ready_state = MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY,
+	    set_state = MEMBARRIER_STATE_PRIVATE_EXPEDITED,
+	    ret;
+
+	if (flags == MEMBARRIER_FLAG_SYNC_CORE) {
+		if (!IS_ENABLED(CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE))
+			return -EINVAL;
+		ready_state =
+			MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE_READY;
+	} else if (flags == MEMBARRIER_FLAG_RSEQ) {
+		if (!IS_ENABLED(CONFIG_RSEQ))
+			return -EINVAL;
+		ready_state =
+			MEMBARRIER_STATE_PRIVATE_EXPEDITED_RSEQ_READY;
+	} else {
+		WARN_ON_ONCE(flags);
+	}
+
+	/*
+	 * We need to consider threads belonging to different thread
+	 * groups, which use the same mm. (CLONE_VM but not
+	 * CLONE_THREAD).
+	 */
+	if ((atomic_read(&mm->membarrier_state) & ready_state) == ready_state)
+		return 0;
+	if (flags & MEMBARRIER_FLAG_SYNC_CORE)
+		set_state |= MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE;
+	if (flags & MEMBARRIER_FLAG_RSEQ)
+		set_state |= MEMBARRIER_STATE_PRIVATE_EXPEDITED_RSEQ;
+	atomic_or(set_state, &mm->membarrier_state);
+	ret = sync_runqueues_membarrier_state(mm);
+	if (ret)
+		return ret;
+	atomic_or(ready_state, &mm->membarrier_state);
+
+	return 0;
+}
+
+/**
+ * sys_membarrier - issue memory barriers on a set of threads
+ * @cmd:    Takes command values defined in enum membarrier_cmd.
+ * @flags:  Currently needs to be 0 for all commands other than
+ *          MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ: in the latter
+ *          case it can be MEMBARRIER_CMD_FLAG_CPU, indicating that @cpu_id
+ *          contains the CPU on which to interrupt (= restart)
+ *          the RSEQ critical section.
+ * @cpu_id: if @flags == MEMBARRIER_CMD_FLAG_CPU, indicates the cpu on which
+ *          RSEQ CS should be interrupted (@cmd must be
+ *          MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ).
+ *
+ * If this system call is not implemented, -ENOSYS is returned. If the
+ * command specified does not exist, not available on the running
+ * kernel, or if the command argument is invalid, this system call
+ * returns -EINVAL. For a given command, with flags argument set to 0,
+ * if this system call returns -ENOSYS or -EINVAL, it is guaranteed to
+ * always return the same value until reboot. In addition, it can return
+ * -ENOMEM if there is not enough memory available to perform the system
+ * call.
+ *
+ * All memory accesses performed in program order from each targeted thread
+ * is guaranteed to be ordered with respect to sys_membarrier(). If we use
+ * the semantic "barrier()" to represent a compiler barrier forcing memory
+ * accesses to be performed in program order across the barrier, and
+ * smp_mb() to represent explicit memory barriers forcing full memory
+ * ordering across the barrier, we have the following ordering table for
+ * each pair of barrier(), sys_membarrier() and smp_mb():
+ *
+ * The pair ordering is detailed as (O: ordered, X: not ordered):
+ *
+ *                        barrier()   smp_mb() sys_membarrier()
+ *        barrier()          X           X            O
+ *        smp_mb()           X           O            O
+ *        sys_membarrier()   O           O            O
+ */
+SYSCALL_DEFINE3(membarrier, int, cmd, unsigned int, flags, int, cpu_id)
+{
+	switch (cmd) {
+	case MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ:
+		if (unlikely(flags && flags != MEMBARRIER_CMD_FLAG_CPU))
+			return -EINVAL;
+		break;
+	default:
+		if (unlikely(flags))
+			return -EINVAL;
+	}
+
+	if (!(flags & MEMBARRIER_CMD_FLAG_CPU))
+		cpu_id = -1;
+
+	switch (cmd) {
+	case MEMBARRIER_CMD_QUERY:
+	{
+		int cmd_mask = MEMBARRIER_CMD_BITMASK;
+
+		if (tick_nohz_full_enabled())
+			cmd_mask &= ~MEMBARRIER_CMD_GLOBAL;
+		return cmd_mask;
+	}
+	case MEMBARRIER_CMD_GLOBAL:
+		/* MEMBARRIER_CMD_GLOBAL is not compatible with nohz_full. */
+		if (tick_nohz_full_enabled())
+			return -EINVAL;
+		if (num_online_cpus() > 1)
+			synchronize_rcu();
+		return 0;
+	case MEMBARRIER_CMD_GLOBAL_EXPEDITED:
+		return membarrier_global_expedited();
+	case MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED:
+		return membarrier_register_global_expedited();
+	case MEMBARRIER_CMD_PRIVATE_EXPEDITED:
+		return membarrier_private_expedited(0, cpu_id);
+	case MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED:
+		return membarrier_register_private_expedited(0);
+	case MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE:
+		return membarrier_private_expedited(MEMBARRIER_FLAG_SYNC_CORE, cpu_id);
+	case MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE:
+		return membarrier_register_private_expedited(MEMBARRIER_FLAG_SYNC_CORE);
+	case MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ:
+		return membarrier_private_expedited(MEMBARRIER_FLAG_RSEQ, cpu_id);
+	case MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ:
+		return membarrier_register_private_expedited(MEMBARRIER_FLAG_RSEQ);
+	default:
+		return -EINVAL;
+	}
+}
diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
new file mode 100644
index 000000000..0f3107682
--- /dev/null
+++ b/kernel/sched/pelt.c
@@ -0,0 +1,469 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Per Entity Load Tracking
+ *
+ *  Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ *  Interactivity improvements by Mike Galbraith
+ *  (C) 2007 Mike Galbraith <efault@gmx.de>
+ *
+ *  Various enhancements by Dmitry Adamushko.
+ *  (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com>
+ *
+ *  Group scheduling enhancements by Srivatsa Vaddagiri
+ *  Copyright IBM Corporation, 2007
+ *  Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
+ *
+ *  Scaled math optimizations by Thomas Gleixner
+ *  Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de>
+ *
+ *  Adaptive scheduling granularity, math enhancements by Peter Zijlstra
+ *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
+ *
+ *  Move PELT related code from fair.c into this pelt.c file
+ *  Author: Vincent Guittot <vincent.guittot@linaro.org>
+ */
+
+/*
+ * Approximate:
+ *   val * y^n,    where y^32 ~= 0.5 (~1 scheduling period)
+ */
+static u64 decay_load(u64 val, u64 n)
+{
+	unsigned int local_n;
+
+	if (unlikely(n > LOAD_AVG_PERIOD * 63))
+		return 0;
+
+	/* after bounds checking we can collapse to 32-bit */
+	local_n = n;
+
+	/*
+	 * As y^PERIOD = 1/2, we can combine
+	 *    y^n = 1/2^(n/PERIOD) * y^(n%PERIOD)
+	 * With a look-up table which covers y^n (n<PERIOD)
+	 *
+	 * To achieve constant time decay_load.
+	 */
+	if (unlikely(local_n >= LOAD_AVG_PERIOD)) {
+		val >>= local_n / LOAD_AVG_PERIOD;
+		local_n %= LOAD_AVG_PERIOD;
+	}
+
+	val = mul_u64_u32_shr(val, runnable_avg_yN_inv[local_n], 32);
+	return val;
+}
+
+static u32 __accumulate_pelt_segments(u64 periods, u32 d1, u32 d3)
+{
+	u32 c1, c2, c3 = d3; /* y^0 == 1 */
+
+	/*
+	 * c1 = d1 y^p
+	 */
+	c1 = decay_load((u64)d1, periods);
+
+	/*
+	 *            p-1
+	 * c2 = 1024 \Sum y^n
+	 *            n=1
+	 *
+	 *              inf        inf
+	 *    = 1024 ( \Sum y^n - \Sum y^n - y^0 )
+	 *              n=0        n=p
+	 */
+	c2 = LOAD_AVG_MAX - decay_load(LOAD_AVG_MAX, periods) - 1024;
+
+	return c1 + c2 + c3;
+}
+
+/*
+ * Accumulate the three separate parts of the sum; d1 the remainder
+ * of the last (incomplete) period, d2 the span of full periods and d3
+ * the remainder of the (incomplete) current period.
+ *
+ *           d1          d2           d3
+ *           ^           ^            ^
+ *           |           |            |
+ *         |<->|<----------------->|<--->|
+ * ... |---x---|------| ... |------|-----x (now)
+ *
+ *                           p-1
+ * u' = (u + d1) y^p + 1024 \Sum y^n + d3 y^0
+ *                           n=1
+ *
+ *    = u y^p +					(Step 1)
+ *
+ *                     p-1
+ *      d1 y^p + 1024 \Sum y^n + d3 y^0		(Step 2)
+ *                     n=1
+ */
+static __always_inline u32
+accumulate_sum(u64 delta, struct sched_avg *sa,
+	       unsigned long load, unsigned long runnable, int running)
+{
+	u32 contrib = (u32)delta; /* p == 0 -> delta < 1024 */
+	u64 periods;
+
+	delta += sa->period_contrib;
+	periods = delta / 1024; /* A period is 1024us (~1ms) */
+
+	/*
+	 * Step 1: decay old *_sum if we crossed period boundaries.
+	 */
+	if (periods) {
+		sa->load_sum = decay_load(sa->load_sum, periods);
+		sa->runnable_sum =
+			decay_load(sa->runnable_sum, periods);
+		sa->util_sum = decay_load((u64)(sa->util_sum), periods);
+
+		/*
+		 * Step 2
+		 */
+		delta %= 1024;
+		if (load) {
+			/*
+			 * This relies on the:
+			 *
+			 * if (!load)
+			 *	runnable = running = 0;
+			 *
+			 * clause from ___update_load_sum(); this results in
+			 * the below usage of @contrib to disappear entirely,
+			 * so no point in calculating it.
+			 */
+			contrib = __accumulate_pelt_segments(periods,
+					1024 - sa->period_contrib, delta);
+		}
+	}
+	sa->period_contrib = delta;
+
+	if (load)
+		sa->load_sum += load * contrib;
+	if (runnable)
+		sa->runnable_sum += runnable * contrib << SCHED_CAPACITY_SHIFT;
+	if (running)
+		sa->util_sum += contrib << SCHED_CAPACITY_SHIFT;
+
+	return periods;
+}
+
+/*
+ * We can represent the historical contribution to runnable average as the
+ * coefficients of a geometric series.  To do this we sub-divide our runnable
+ * history into segments of approximately 1ms (1024us); label the segment that
+ * occurred N-ms ago p_N, with p_0 corresponding to the current period, e.g.
+ *
+ * [<- 1024us ->|<- 1024us ->|<- 1024us ->| ...
+ *      p0            p1           p2
+ *     (now)       (~1ms ago)  (~2ms ago)
+ *
+ * Let u_i denote the fraction of p_i that the entity was runnable.
+ *
+ * We then designate the fractions u_i as our co-efficients, yielding the
+ * following representation of historical load:
+ *   u_0 + u_1*y + u_2*y^2 + u_3*y^3 + ...
+ *
+ * We choose y based on the with of a reasonably scheduling period, fixing:
+ *   y^32 = 0.5
+ *
+ * This means that the contribution to load ~32ms ago (u_32) will be weighted
+ * approximately half as much as the contribution to load within the last ms
+ * (u_0).
+ *
+ * When a period "rolls over" and we have new u_0`, multiplying the previous
+ * sum again by y is sufficient to update:
+ *   load_avg = u_0` + y*(u_0 + u_1*y + u_2*y^2 + ... )
+ *            = u_0 + u_1*y + u_2*y^2 + ... [re-labeling u_i --> u_{i+1}]
+ */
+static __always_inline int
+___update_load_sum(u64 now, struct sched_avg *sa,
+		  unsigned long load, unsigned long runnable, int running)
+{
+	u64 delta;
+
+	delta = now - sa->last_update_time;
+	/*
+	 * This should only happen when time goes backwards, which it
+	 * unfortunately does during sched clock init when we swap over to TSC.
+	 */
+	if ((s64)delta < 0) {
+		sa->last_update_time = now;
+		return 0;
+	}
+
+	/*
+	 * Use 1024ns as the unit of measurement since it's a reasonable
+	 * approximation of 1us and fast to compute.
+	 */
+	delta >>= 10;
+	if (!delta)
+		return 0;
+
+	sa->last_update_time += delta << 10;
+
+	/*
+	 * running is a subset of runnable (weight) so running can't be set if
+	 * runnable is clear. But there are some corner cases where the current
+	 * se has been already dequeued but cfs_rq->curr still points to it.
+	 * This means that weight will be 0 but not running for a sched_entity
+	 * but also for a cfs_rq if the latter becomes idle. As an example,
+	 * this happens during idle_balance() which calls
+	 * update_blocked_averages().
+	 *
+	 * Also see the comment in accumulate_sum().
+	 */
+	if (!load)
+		runnable = running = 0;
+
+	/*
+	 * Now we know we crossed measurement unit boundaries. The *_avg
+	 * accrues by two steps:
+	 *
+	 * Step 1: accumulate *_sum since last_update_time. If we haven't
+	 * crossed period boundaries, finish.
+	 */
+	if (!accumulate_sum(delta, sa, load, runnable, running))
+		return 0;
+
+	return 1;
+}
+
+/*
+ * When syncing *_avg with *_sum, we must take into account the current
+ * position in the PELT segment otherwise the remaining part of the segment
+ * will be considered as idle time whereas it's not yet elapsed and this will
+ * generate unwanted oscillation in the range [1002..1024[.
+ *
+ * The max value of *_sum varies with the position in the time segment and is
+ * equals to :
+ *
+ *   LOAD_AVG_MAX*y + sa->period_contrib
+ *
+ * which can be simplified into:
+ *
+ *   LOAD_AVG_MAX - 1024 + sa->period_contrib
+ *
+ * because LOAD_AVG_MAX*y == LOAD_AVG_MAX-1024
+ *
+ * The same care must be taken when a sched entity is added, updated or
+ * removed from a cfs_rq and we need to update sched_avg. Scheduler entities
+ * and the cfs rq, to which they are attached, have the same position in the
+ * time segment because they use the same clock. This means that we can use
+ * the period_contrib of cfs_rq when updating the sched_avg of a sched_entity
+ * if it's more convenient.
+ */
+static __always_inline void
+___update_load_avg(struct sched_avg *sa, unsigned long load)
+{
+	u32 divider = get_pelt_divider(sa);
+
+	/*
+	 * Step 2: update *_avg.
+	 */
+	sa->load_avg = div_u64(load * sa->load_sum, divider);
+	sa->runnable_avg = div_u64(sa->runnable_sum, divider);
+	WRITE_ONCE(sa->util_avg, sa->util_sum / divider);
+}
+
+/*
+ * sched_entity:
+ *
+ *   task:
+ *     se_weight()   = se->load.weight
+ *     se_runnable() = !!on_rq
+ *
+ *   group: [ see update_cfs_group() ]
+ *     se_weight()   = tg->weight * grq->load_avg / tg->load_avg
+ *     se_runnable() = grq->h_nr_running
+ *
+ *   runnable_sum = se_runnable() * runnable = grq->runnable_sum
+ *   runnable_avg = runnable_sum
+ *
+ *   load_sum := runnable
+ *   load_avg = se_weight(se) * load_sum
+ *
+ * cfq_rq:
+ *
+ *   runnable_sum = \Sum se->avg.runnable_sum
+ *   runnable_avg = \Sum se->avg.runnable_avg
+ *
+ *   load_sum = \Sum se_weight(se) * se->avg.load_sum
+ *   load_avg = \Sum se->avg.load_avg
+ */
+
+int __update_load_avg_blocked_se(u64 now, struct sched_entity *se)
+{
+	if (___update_load_sum(now, &se->avg, 0, 0, 0)) {
+		___update_load_avg(&se->avg, se_weight(se));
+		trace_pelt_se_tp(se);
+		return 1;
+	}
+
+	return 0;
+}
+
+int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+	if (___update_load_sum(now, &se->avg, !!se->on_rq, se_runnable(se),
+				cfs_rq->curr == se)) {
+
+		___update_load_avg(&se->avg, se_weight(se));
+		cfs_se_util_change(&se->avg);
+		trace_pelt_se_tp(se);
+		return 1;
+	}
+
+	return 0;
+}
+
+int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq)
+{
+	if (___update_load_sum(now, &cfs_rq->avg,
+				scale_load_down(cfs_rq->load.weight),
+				cfs_rq->h_nr_running,
+				cfs_rq->curr != NULL)) {
+
+		___update_load_avg(&cfs_rq->avg, 1);
+		trace_pelt_cfs_tp(cfs_rq);
+		return 1;
+	}
+
+	return 0;
+}
+
+/*
+ * rt_rq:
+ *
+ *   util_sum = \Sum se->avg.util_sum but se->avg.util_sum is not tracked
+ *   util_sum = cpu_scale * load_sum
+ *   runnable_sum = util_sum
+ *
+ *   load_avg and runnable_avg are not supported and meaningless.
+ *
+ */
+
+int update_rt_rq_load_avg(u64 now, struct rq *rq, int running)
+{
+	if (___update_load_sum(now, &rq->avg_rt,
+				running,
+				running,
+				running)) {
+
+		___update_load_avg(&rq->avg_rt, 1);
+		trace_pelt_rt_tp(rq);
+		return 1;
+	}
+
+	return 0;
+}
+
+/*
+ * dl_rq:
+ *
+ *   util_sum = \Sum se->avg.util_sum but se->avg.util_sum is not tracked
+ *   util_sum = cpu_scale * load_sum
+ *   runnable_sum = util_sum
+ *
+ *   load_avg and runnable_avg are not supported and meaningless.
+ *
+ */
+
+int update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
+{
+	if (___update_load_sum(now, &rq->avg_dl,
+				running,
+				running,
+				running)) {
+
+		___update_load_avg(&rq->avg_dl, 1);
+		trace_pelt_dl_tp(rq);
+		return 1;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_SCHED_THERMAL_PRESSURE
+/*
+ * thermal:
+ *
+ *   load_sum = \Sum se->avg.load_sum but se->avg.load_sum is not tracked
+ *
+ *   util_avg and runnable_load_avg are not supported and meaningless.
+ *
+ * Unlike rt/dl utilization tracking that track time spent by a cpu
+ * running a rt/dl task through util_avg, the average thermal pressure is
+ * tracked through load_avg. This is because thermal pressure signal is
+ * time weighted "delta" capacity unlike util_avg which is binary.
+ * "delta capacity" =  actual capacity  -
+ *			capped capacity a cpu due to a thermal event.
+ */
+
+int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
+{
+	if (___update_load_sum(now, &rq->avg_thermal,
+			       capacity,
+			       capacity,
+			       capacity)) {
+		___update_load_avg(&rq->avg_thermal, 1);
+		trace_pelt_thermal_tp(rq);
+		return 1;
+	}
+
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+/*
+ * irq:
+ *
+ *   util_sum = \Sum se->avg.util_sum but se->avg.util_sum is not tracked
+ *   util_sum = cpu_scale * load_sum
+ *   runnable_sum = util_sum
+ *
+ *   load_avg and runnable_avg are not supported and meaningless.
+ *
+ */
+
+int update_irq_load_avg(struct rq *rq, u64 running)
+{
+	int ret = 0;
+
+	/*
+	 * We can't use clock_pelt because irq time is not accounted in
+	 * clock_task. Instead we directly scale the running time to
+	 * reflect the real amount of computation
+	 */
+	running = cap_scale(running, arch_scale_freq_capacity(cpu_of(rq)));
+	running = cap_scale(running, arch_scale_cpu_capacity(cpu_of(rq)));
+
+	/*
+	 * We know the time that has been used by interrupt since last update
+	 * but we don't when. Let be pessimistic and assume that interrupt has
+	 * happened just before the update. This is not so far from reality
+	 * because interrupt will most probably wake up task and trig an update
+	 * of rq clock during which the metric is updated.
+	 * We start to decay with normal context time and then we add the
+	 * interrupt context time.
+	 * We can safely remove running from rq->clock because
+	 * rq->clock += delta with delta >= running
+	 */
+	ret = ___update_load_sum(rq->clock - running, &rq->avg_irq,
+				0,
+				0,
+				0);
+	ret += ___update_load_sum(rq->clock, &rq->avg_irq,
+				1,
+				1,
+				1);
+
+	if (ret) {
+		___update_load_avg(&rq->avg_irq, 1);
+		trace_pelt_irq_tp(rq);
+	}
+
+	return ret;
+}
+#endif
diff --git a/kernel/sched/pelt.h b/kernel/sched/pelt.h
new file mode 100644
index 000000000..3a0e0dc28
--- /dev/null
+++ b/kernel/sched/pelt.h
@@ -0,0 +1,235 @@
+#ifdef CONFIG_SMP
+#include "sched-pelt.h"
+
+int __update_load_avg_blocked_se(u64 now, struct sched_entity *se);
+int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se);
+int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq);
+int update_rt_rq_load_avg(u64 now, struct rq *rq, int running);
+int update_dl_rq_load_avg(u64 now, struct rq *rq, int running);
+
+#ifdef CONFIG_SCHED_THERMAL_PRESSURE
+int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity);
+
+static inline u64 thermal_load_avg(struct rq *rq)
+{
+	return READ_ONCE(rq->avg_thermal.load_avg);
+}
+#else
+static inline int
+update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
+{
+	return 0;
+}
+
+static inline u64 thermal_load_avg(struct rq *rq)
+{
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+int update_irq_load_avg(struct rq *rq, u64 running);
+#else
+static inline int
+update_irq_load_avg(struct rq *rq, u64 running)
+{
+	return 0;
+}
+#endif
+
+#define PELT_MIN_DIVIDER	(LOAD_AVG_MAX - 1024)
+
+static inline u32 get_pelt_divider(struct sched_avg *avg)
+{
+	return PELT_MIN_DIVIDER + avg->period_contrib;
+}
+
+static inline void cfs_se_util_change(struct sched_avg *avg)
+{
+	unsigned int enqueued;
+
+	if (!sched_feat(UTIL_EST))
+		return;
+
+	/* Avoid store if the flag has been already reset */
+	enqueued = avg->util_est.enqueued;
+	if (!(enqueued & UTIL_AVG_UNCHANGED))
+		return;
+
+	/* Reset flag to report util_avg has been updated */
+	enqueued &= ~UTIL_AVG_UNCHANGED;
+	WRITE_ONCE(avg->util_est.enqueued, enqueued);
+}
+
+static inline u64 rq_clock_pelt(struct rq *rq)
+{
+	lockdep_assert_rq_held(rq);
+	assert_clock_updated(rq);
+
+	return rq->clock_pelt - rq->lost_idle_time;
+}
+
+/* The rq is idle, we can sync to clock_task */
+static inline void _update_idle_rq_clock_pelt(struct rq *rq)
+{
+	rq->clock_pelt  = rq_clock_task(rq);
+
+	u64_u32_store(rq->clock_idle, rq_clock(rq));
+	/* Paired with smp_rmb in migrate_se_pelt_lag() */
+	smp_wmb();
+	u64_u32_store(rq->clock_pelt_idle, rq_clock_pelt(rq));
+}
+
+/*
+ * The clock_pelt scales the time to reflect the effective amount of
+ * computation done during the running delta time but then sync back to
+ * clock_task when rq is idle.
+ *
+ *
+ * absolute time   | 1| 2| 3| 4| 5| 6| 7| 8| 9|10|11|12|13|14|15|16
+ * @ max capacity  ------******---------------******---------------
+ * @ half capacity ------************---------************---------
+ * clock pelt      | 1| 2|    3|    4| 7| 8| 9|   10|   11|14|15|16
+ *
+ */
+static inline void update_rq_clock_pelt(struct rq *rq, s64 delta)
+{
+	if (unlikely(is_idle_task(rq->curr))) {
+		_update_idle_rq_clock_pelt(rq);
+		return;
+	}
+
+	/*
+	 * When a rq runs at a lower compute capacity, it will need
+	 * more time to do the same amount of work than at max
+	 * capacity. In order to be invariant, we scale the delta to
+	 * reflect how much work has been really done.
+	 * Running longer results in stealing idle time that will
+	 * disturb the load signal compared to max capacity. This
+	 * stolen idle time will be automatically reflected when the
+	 * rq will be idle and the clock will be synced with
+	 * rq_clock_task.
+	 */
+
+	/*
+	 * Scale the elapsed time to reflect the real amount of
+	 * computation
+	 */
+	delta = cap_scale(delta, arch_scale_cpu_capacity(cpu_of(rq)));
+	delta = cap_scale(delta, arch_scale_freq_capacity(cpu_of(rq)));
+
+	rq->clock_pelt += delta;
+}
+
+/*
+ * When rq becomes idle, we have to check if it has lost idle time
+ * because it was fully busy. A rq is fully used when the /Sum util_sum
+ * is greater or equal to:
+ * (LOAD_AVG_MAX - 1024 + rq->cfs.avg.period_contrib) << SCHED_CAPACITY_SHIFT;
+ * For optimization and computing rounding purpose, we don't take into account
+ * the position in the current window (period_contrib) and we use the higher
+ * bound of util_sum to decide.
+ */
+static inline void update_idle_rq_clock_pelt(struct rq *rq)
+{
+	u32 divider = ((LOAD_AVG_MAX - 1024) << SCHED_CAPACITY_SHIFT) - LOAD_AVG_MAX;
+	u32 util_sum = rq->cfs.avg.util_sum;
+	util_sum += rq->avg_rt.util_sum;
+	util_sum += rq->avg_dl.util_sum;
+
+	/*
+	 * Reflecting stolen time makes sense only if the idle
+	 * phase would be present at max capacity. As soon as the
+	 * utilization of a rq has reached the maximum value, it is
+	 * considered as an always running rq without idle time to
+	 * steal. This potential idle time is considered as lost in
+	 * this case. We keep track of this lost idle time compare to
+	 * rq's clock_task.
+	 */
+	if (util_sum >= divider)
+		rq->lost_idle_time += rq_clock_task(rq) - rq->clock_pelt;
+
+	_update_idle_rq_clock_pelt(rq);
+}
+
+#ifdef CONFIG_CFS_BANDWIDTH
+static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
+{
+	u64 throttled;
+
+	if (unlikely(cfs_rq->throttle_count))
+		throttled = U64_MAX;
+	else
+		throttled = cfs_rq->throttled_clock_pelt_time;
+
+	u64_u32_store(cfs_rq->throttled_pelt_idle, throttled);
+}
+
+/* rq->task_clock normalized against any time this cfs_rq has spent throttled */
+static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
+{
+	if (unlikely(cfs_rq->throttle_count))
+		return cfs_rq->throttled_clock_pelt - cfs_rq->throttled_clock_pelt_time;
+
+	return rq_clock_pelt(rq_of(cfs_rq)) - cfs_rq->throttled_clock_pelt_time;
+}
+#else
+static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) { }
+static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
+{
+	return rq_clock_pelt(rq_of(cfs_rq));
+}
+#endif
+
+#else
+
+static inline int
+update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
+{
+	return 0;
+}
+
+static inline int
+update_rt_rq_load_avg(u64 now, struct rq *rq, int running)
+{
+	return 0;
+}
+
+static inline int
+update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
+{
+	return 0;
+}
+
+static inline int
+update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
+{
+	return 0;
+}
+
+static inline u64 thermal_load_avg(struct rq *rq)
+{
+	return 0;
+}
+
+static inline int
+update_irq_load_avg(struct rq *rq, u64 running)
+{
+	return 0;
+}
+
+static inline u64 rq_clock_pelt(struct rq *rq)
+{
+	return rq_clock_task(rq);
+}
+
+static inline void
+update_rq_clock_pelt(struct rq *rq, s64 delta) { }
+
+static inline void
+update_idle_rq_clock_pelt(struct rq *rq) { }
+
+static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) { }
+#endif
+
+
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
new file mode 100644
index 000000000..80d8c10e9
--- /dev/null
+++ b/kernel/sched/psi.c
@@ -0,0 +1,1662 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Pressure stall information for CPU, memory and IO
+ *
+ * Copyright (c) 2018 Facebook, Inc.
+ * Author: Johannes Weiner <hannes@cmpxchg.org>
+ *
+ * Polling support by Suren Baghdasaryan <surenb@google.com>
+ * Copyright (c) 2018 Google, Inc.
+ *
+ * When CPU, memory and IO are contended, tasks experience delays that
+ * reduce throughput and introduce latencies into the workload. Memory
+ * and IO contention, in addition, can cause a full loss of forward
+ * progress in which the CPU goes idle.
+ *
+ * This code aggregates individual task delays into resource pressure
+ * metrics that indicate problems with both workload health and
+ * resource utilization.
+ *
+ *			Model
+ *
+ * The time in which a task can execute on a CPU is our baseline for
+ * productivity. Pressure expresses the amount of time in which this
+ * potential cannot be realized due to resource contention.
+ *
+ * This concept of productivity has two components: the workload and
+ * the CPU. To measure the impact of pressure on both, we define two
+ * contention states for a resource: SOME and FULL.
+ *
+ * In the SOME state of a given resource, one or more tasks are
+ * delayed on that resource. This affects the workload's ability to
+ * perform work, but the CPU may still be executing other tasks.
+ *
+ * In the FULL state of a given resource, all non-idle tasks are
+ * delayed on that resource such that nobody is advancing and the CPU
+ * goes idle. This leaves both workload and CPU unproductive.
+ *
+ *	SOME = nr_delayed_tasks != 0
+ *	FULL = nr_delayed_tasks != 0 && nr_productive_tasks == 0
+ *
+ * What it means for a task to be productive is defined differently
+ * for each resource. For IO, productive means a running task. For
+ * memory, productive means a running task that isn't a reclaimer. For
+ * CPU, productive means an oncpu task.
+ *
+ * Naturally, the FULL state doesn't exist for the CPU resource at the
+ * system level, but exist at the cgroup level. At the cgroup level,
+ * FULL means all non-idle tasks in the cgroup are delayed on the CPU
+ * resource which is being used by others outside of the cgroup or
+ * throttled by the cgroup cpu.max configuration.
+ *
+ * The percentage of wallclock time spent in those compound stall
+ * states gives pressure numbers between 0 and 100 for each resource,
+ * where the SOME percentage indicates workload slowdowns and the FULL
+ * percentage indicates reduced CPU utilization:
+ *
+ *	%SOME = time(SOME) / period
+ *	%FULL = time(FULL) / period
+ *
+ *			Multiple CPUs
+ *
+ * The more tasks and available CPUs there are, the more work can be
+ * performed concurrently. This means that the potential that can go
+ * unrealized due to resource contention *also* scales with non-idle
+ * tasks and CPUs.
+ *
+ * Consider a scenario where 257 number crunching tasks are trying to
+ * run concurrently on 256 CPUs. If we simply aggregated the task
+ * states, we would have to conclude a CPU SOME pressure number of
+ * 100%, since *somebody* is waiting on a runqueue at all
+ * times. However, that is clearly not the amount of contention the
+ * workload is experiencing: only one out of 256 possible execution
+ * threads will be contended at any given time, or about 0.4%.
+ *
+ * Conversely, consider a scenario of 4 tasks and 4 CPUs where at any
+ * given time *one* of the tasks is delayed due to a lack of memory.
+ * Again, looking purely at the task state would yield a memory FULL
+ * pressure number of 0%, since *somebody* is always making forward
+ * progress. But again this wouldn't capture the amount of execution
+ * potential lost, which is 1 out of 4 CPUs, or 25%.
+ *
+ * To calculate wasted potential (pressure) with multiple processors,
+ * we have to base our calculation on the number of non-idle tasks in
+ * conjunction with the number of available CPUs, which is the number
+ * of potential execution threads. SOME becomes then the proportion of
+ * delayed tasks to possible threads, and FULL is the share of possible
+ * threads that are unproductive due to delays:
+ *
+ *	threads = min(nr_nonidle_tasks, nr_cpus)
+ *	   SOME = min(nr_delayed_tasks / threads, 1)
+ *	   FULL = (threads - min(nr_productive_tasks, threads)) / threads
+ *
+ * For the 257 number crunchers on 256 CPUs, this yields:
+ *
+ *	threads = min(257, 256)
+ *	   SOME = min(1 / 256, 1)             = 0.4%
+ *	   FULL = (256 - min(256, 256)) / 256 = 0%
+ *
+ * For the 1 out of 4 memory-delayed tasks, this yields:
+ *
+ *	threads = min(4, 4)
+ *	   SOME = min(1 / 4, 1)               = 25%
+ *	   FULL = (4 - min(3, 4)) / 4         = 25%
+ *
+ * [ Substitute nr_cpus with 1, and you can see that it's a natural
+ *   extension of the single-CPU model. ]
+ *
+ *			Implementation
+ *
+ * To assess the precise time spent in each such state, we would have
+ * to freeze the system on task changes and start/stop the state
+ * clocks accordingly. Obviously that doesn't scale in practice.
+ *
+ * Because the scheduler aims to distribute the compute load evenly
+ * among the available CPUs, we can track task state locally to each
+ * CPU and, at much lower frequency, extrapolate the global state for
+ * the cumulative stall times and the running averages.
+ *
+ * For each runqueue, we track:
+ *
+ *	   tSOME[cpu] = time(nr_delayed_tasks[cpu] != 0)
+ *	   tFULL[cpu] = time(nr_delayed_tasks[cpu] && !nr_productive_tasks[cpu])
+ *	tNONIDLE[cpu] = time(nr_nonidle_tasks[cpu] != 0)
+ *
+ * and then periodically aggregate:
+ *
+ *	tNONIDLE = sum(tNONIDLE[i])
+ *
+ *	   tSOME = sum(tSOME[i] * tNONIDLE[i]) / tNONIDLE
+ *	   tFULL = sum(tFULL[i] * tNONIDLE[i]) / tNONIDLE
+ *
+ *	   %SOME = tSOME / period
+ *	   %FULL = tFULL / period
+ *
+ * This gives us an approximation of pressure that is practical
+ * cost-wise, yet way more sensitive and accurate than periodic
+ * sampling of the aggregate task states would be.
+ */
+
+static int psi_bug __read_mostly;
+
+DEFINE_STATIC_KEY_FALSE(psi_disabled);
+DEFINE_STATIC_KEY_TRUE(psi_cgroups_enabled);
+
+#ifdef CONFIG_PSI_DEFAULT_DISABLED
+static bool psi_enable;
+#else
+static bool psi_enable = true;
+#endif
+static int __init setup_psi(char *str)
+{
+	return kstrtobool(str, &psi_enable) == 0;
+}
+__setup("psi=", setup_psi);
+
+/* Running averages - we need to be higher-res than loadavg */
+#define PSI_FREQ	(2*HZ+1)	/* 2 sec intervals */
+#define EXP_10s		1677		/* 1/exp(2s/10s) as fixed-point */
+#define EXP_60s		1981		/* 1/exp(2s/60s) */
+#define EXP_300s	2034		/* 1/exp(2s/300s) */
+
+/* PSI trigger definitions */
+#define WINDOW_MIN_US 500000	/* Min window size is 500ms */
+#define WINDOW_MAX_US 10000000	/* Max window size is 10s */
+#define UPDATES_PER_WINDOW 10	/* 10 updates per window */
+
+/* Sampling frequency in nanoseconds */
+static u64 psi_period __read_mostly;
+
+/* System-level pressure and stall tracking */
+static DEFINE_PER_CPU(struct psi_group_cpu, system_group_pcpu);
+struct psi_group psi_system = {
+	.pcpu = &system_group_pcpu,
+};
+
+static void psi_avgs_work(struct work_struct *work);
+
+static void poll_timer_fn(struct timer_list *t);
+
+static void group_init(struct psi_group *group)
+{
+	int cpu;
+
+	group->enabled = true;
+	for_each_possible_cpu(cpu)
+		seqcount_init(&per_cpu_ptr(group->pcpu, cpu)->seq);
+	group->avg_last_update = sched_clock();
+	group->avg_next_update = group->avg_last_update + psi_period;
+	mutex_init(&group->avgs_lock);
+
+	/* Init avg trigger-related members */
+	INIT_LIST_HEAD(&group->avg_triggers);
+	memset(group->avg_nr_triggers, 0, sizeof(group->avg_nr_triggers));
+	INIT_DELAYED_WORK(&group->avgs_work, psi_avgs_work);
+
+	/* Init rtpoll trigger-related members */
+	atomic_set(&group->rtpoll_scheduled, 0);
+	mutex_init(&group->rtpoll_trigger_lock);
+	INIT_LIST_HEAD(&group->rtpoll_triggers);
+	group->rtpoll_min_period = U32_MAX;
+	group->rtpoll_next_update = ULLONG_MAX;
+	init_waitqueue_head(&group->rtpoll_wait);
+	timer_setup(&group->rtpoll_timer, poll_timer_fn, 0);
+	rcu_assign_pointer(group->rtpoll_task, NULL);
+}
+
+void __init psi_init(void)
+{
+	if (!psi_enable) {
+		static_branch_enable(&psi_disabled);
+		static_branch_disable(&psi_cgroups_enabled);
+		return;
+	}
+
+	if (!cgroup_psi_enabled())
+		static_branch_disable(&psi_cgroups_enabled);
+
+	psi_period = jiffies_to_nsecs(PSI_FREQ);
+	group_init(&psi_system);
+}
+
+static bool test_state(unsigned int *tasks, enum psi_states state, bool oncpu)
+{
+	switch (state) {
+	case PSI_IO_SOME:
+		return unlikely(tasks[NR_IOWAIT]);
+	case PSI_IO_FULL:
+		return unlikely(tasks[NR_IOWAIT] && !tasks[NR_RUNNING]);
+	case PSI_MEM_SOME:
+		return unlikely(tasks[NR_MEMSTALL]);
+	case PSI_MEM_FULL:
+		return unlikely(tasks[NR_MEMSTALL] &&
+			tasks[NR_RUNNING] == tasks[NR_MEMSTALL_RUNNING]);
+	case PSI_CPU_SOME:
+		return unlikely(tasks[NR_RUNNING] > oncpu);
+	case PSI_CPU_FULL:
+		return unlikely(tasks[NR_RUNNING] && !oncpu);
+	case PSI_NONIDLE:
+		return tasks[NR_IOWAIT] || tasks[NR_MEMSTALL] ||
+			tasks[NR_RUNNING];
+	default:
+		return false;
+	}
+}
+
+static void get_recent_times(struct psi_group *group, int cpu,
+			     enum psi_aggregators aggregator, u32 *times,
+			     u32 *pchanged_states)
+{
+	struct psi_group_cpu *groupc = per_cpu_ptr(group->pcpu, cpu);
+	int current_cpu = raw_smp_processor_id();
+	unsigned int tasks[NR_PSI_TASK_COUNTS];
+	u64 now, state_start;
+	enum psi_states s;
+	unsigned int seq;
+	u32 state_mask;
+
+	*pchanged_states = 0;
+
+	/* Snapshot a coherent view of the CPU state */
+	do {
+		seq = read_seqcount_begin(&groupc->seq);
+		now = cpu_clock(cpu);
+		memcpy(times, groupc->times, sizeof(groupc->times));
+		state_mask = groupc->state_mask;
+		state_start = groupc->state_start;
+		if (cpu == current_cpu)
+			memcpy(tasks, groupc->tasks, sizeof(groupc->tasks));
+	} while (read_seqcount_retry(&groupc->seq, seq));
+
+	/* Calculate state time deltas against the previous snapshot */
+	for (s = 0; s < NR_PSI_STATES; s++) {
+		u32 delta;
+		/*
+		 * In addition to already concluded states, we also
+		 * incorporate currently active states on the CPU,
+		 * since states may last for many sampling periods.
+		 *
+		 * This way we keep our delta sampling buckets small
+		 * (u32) and our reported pressure close to what's
+		 * actually happening.
+		 */
+		if (state_mask & (1 << s))
+			times[s] += now - state_start;
+
+		delta = times[s] - groupc->times_prev[aggregator][s];
+		groupc->times_prev[aggregator][s] = times[s];
+
+		times[s] = delta;
+		if (delta)
+			*pchanged_states |= (1 << s);
+	}
+
+	/*
+	 * When collect_percpu_times() from the avgs_work, we don't want to
+	 * re-arm avgs_work when all CPUs are IDLE. But the current CPU running
+	 * this avgs_work is never IDLE, cause avgs_work can't be shut off.
+	 * So for the current CPU, we need to re-arm avgs_work only when
+	 * (NR_RUNNING > 1 || NR_IOWAIT > 0 || NR_MEMSTALL > 0), for other CPUs
+	 * we can just check PSI_NONIDLE delta.
+	 */
+	if (current_work() == &group->avgs_work.work) {
+		bool reschedule;
+
+		if (cpu == current_cpu)
+			reschedule = tasks[NR_RUNNING] +
+				     tasks[NR_IOWAIT] +
+				     tasks[NR_MEMSTALL] > 1;
+		else
+			reschedule = *pchanged_states & (1 << PSI_NONIDLE);
+
+		if (reschedule)
+			*pchanged_states |= PSI_STATE_RESCHEDULE;
+	}
+}
+
+static void calc_avgs(unsigned long avg[3], int missed_periods,
+		      u64 time, u64 period)
+{
+	unsigned long pct;
+
+	/* Fill in zeroes for periods of no activity */
+	if (missed_periods) {
+		avg[0] = calc_load_n(avg[0], EXP_10s, 0, missed_periods);
+		avg[1] = calc_load_n(avg[1], EXP_60s, 0, missed_periods);
+		avg[2] = calc_load_n(avg[2], EXP_300s, 0, missed_periods);
+	}
+
+	/* Sample the most recent active period */
+	pct = div_u64(time * 100, period);
+	pct *= FIXED_1;
+	avg[0] = calc_load(avg[0], EXP_10s, pct);
+	avg[1] = calc_load(avg[1], EXP_60s, pct);
+	avg[2] = calc_load(avg[2], EXP_300s, pct);
+}
+
+static void collect_percpu_times(struct psi_group *group,
+				 enum psi_aggregators aggregator,
+				 u32 *pchanged_states)
+{
+	u64 deltas[NR_PSI_STATES - 1] = { 0, };
+	unsigned long nonidle_total = 0;
+	u32 changed_states = 0;
+	int cpu;
+	int s;
+
+	/*
+	 * Collect the per-cpu time buckets and average them into a
+	 * single time sample that is normalized to wallclock time.
+	 *
+	 * For averaging, each CPU is weighted by its non-idle time in
+	 * the sampling period. This eliminates artifacts from uneven
+	 * loading, or even entirely idle CPUs.
+	 */
+	for_each_possible_cpu(cpu) {
+		u32 times[NR_PSI_STATES];
+		u32 nonidle;
+		u32 cpu_changed_states;
+
+		get_recent_times(group, cpu, aggregator, times,
+				&cpu_changed_states);
+		changed_states |= cpu_changed_states;
+
+		nonidle = nsecs_to_jiffies(times[PSI_NONIDLE]);
+		nonidle_total += nonidle;
+
+		for (s = 0; s < PSI_NONIDLE; s++)
+			deltas[s] += (u64)times[s] * nonidle;
+	}
+
+	/*
+	 * Integrate the sample into the running statistics that are
+	 * reported to userspace: the cumulative stall times and the
+	 * decaying averages.
+	 *
+	 * Pressure percentages are sampled at PSI_FREQ. We might be
+	 * called more often when the user polls more frequently than
+	 * that; we might be called less often when there is no task
+	 * activity, thus no data, and clock ticks are sporadic. The
+	 * below handles both.
+	 */
+
+	/* total= */
+	for (s = 0; s < NR_PSI_STATES - 1; s++)
+		group->total[aggregator][s] +=
+				div_u64(deltas[s], max(nonidle_total, 1UL));
+
+	if (pchanged_states)
+		*pchanged_states = changed_states;
+}
+
+/* Trigger tracking window manipulations */
+static void window_reset(struct psi_window *win, u64 now, u64 value,
+			 u64 prev_growth)
+{
+	win->start_time = now;
+	win->start_value = value;
+	win->prev_growth = prev_growth;
+}
+
+/*
+ * PSI growth tracking window update and growth calculation routine.
+ *
+ * This approximates a sliding tracking window by interpolating
+ * partially elapsed windows using historical growth data from the
+ * previous intervals. This minimizes memory requirements (by not storing
+ * all the intermediate values in the previous window) and simplifies
+ * the calculations. It works well because PSI signal changes only in
+ * positive direction and over relatively small window sizes the growth
+ * is close to linear.
+ */
+static u64 window_update(struct psi_window *win, u64 now, u64 value)
+{
+	u64 elapsed;
+	u64 growth;
+
+	elapsed = now - win->start_time;
+	growth = value - win->start_value;
+	/*
+	 * After each tracking window passes win->start_value and
+	 * win->start_time get reset and win->prev_growth stores
+	 * the average per-window growth of the previous window.
+	 * win->prev_growth is then used to interpolate additional
+	 * growth from the previous window assuming it was linear.
+	 */
+	if (elapsed > win->size)
+		window_reset(win, now, value, growth);
+	else {
+		u32 remaining;
+
+		remaining = win->size - elapsed;
+		growth += div64_u64(win->prev_growth * remaining, win->size);
+	}
+
+	return growth;
+}
+
+static u64 update_triggers(struct psi_group *group, u64 now, bool *update_total,
+						   enum psi_aggregators aggregator)
+{
+	struct psi_trigger *t;
+	u64 *total = group->total[aggregator];
+	struct list_head *triggers;
+	u64 *aggregator_total;
+	*update_total = false;
+
+	if (aggregator == PSI_AVGS) {
+		triggers = &group->avg_triggers;
+		aggregator_total = group->avg_total;
+	} else {
+		triggers = &group->rtpoll_triggers;
+		aggregator_total = group->rtpoll_total;
+	}
+
+	/*
+	 * On subsequent updates, calculate growth deltas and let
+	 * watchers know when their specified thresholds are exceeded.
+	 */
+	list_for_each_entry(t, triggers, node) {
+		u64 growth;
+		bool new_stall;
+
+		new_stall = aggregator_total[t->state] != total[t->state];
+
+		/* Check for stall activity or a previous threshold breach */
+		if (!new_stall && !t->pending_event)
+			continue;
+		/*
+		 * Check for new stall activity, as well as deferred
+		 * events that occurred in the last window after the
+		 * trigger had already fired (we want to ratelimit
+		 * events without dropping any).
+		 */
+		if (new_stall) {
+			/*
+			 * Multiple triggers might be looking at the same state,
+			 * remember to update group->polling_total[] once we've
+			 * been through all of them. Also remember to extend the
+			 * polling time if we see new stall activity.
+			 */
+			*update_total = true;
+
+			/* Calculate growth since last update */
+			growth = window_update(&t->win, now, total[t->state]);
+			if (!t->pending_event) {
+				if (growth < t->threshold)
+					continue;
+
+				t->pending_event = true;
+			}
+		}
+		/* Limit event signaling to once per window */
+		if (now < t->last_event_time + t->win.size)
+			continue;
+
+		/* Generate an event */
+		if (cmpxchg(&t->event, 0, 1) == 0) {
+			if (t->of)
+				kernfs_notify(t->of->kn);
+			else
+				wake_up_interruptible(&t->event_wait);
+		}
+		t->last_event_time = now;
+		/* Reset threshold breach flag once event got generated */
+		t->pending_event = false;
+	}
+
+	return now + group->rtpoll_min_period;
+}
+
+static u64 update_averages(struct psi_group *group, u64 now)
+{
+	unsigned long missed_periods = 0;
+	u64 expires, period;
+	u64 avg_next_update;
+	int s;
+
+	/* avgX= */
+	expires = group->avg_next_update;
+	if (now - expires >= psi_period)
+		missed_periods = div_u64(now - expires, psi_period);
+
+	/*
+	 * The periodic clock tick can get delayed for various
+	 * reasons, especially on loaded systems. To avoid clock
+	 * drift, we schedule the clock in fixed psi_period intervals.
+	 * But the deltas we sample out of the per-cpu buckets above
+	 * are based on the actual time elapsing between clock ticks.
+	 */
+	avg_next_update = expires + ((1 + missed_periods) * psi_period);
+	period = now - (group->avg_last_update + (missed_periods * psi_period));
+	group->avg_last_update = now;
+
+	for (s = 0; s < NR_PSI_STATES - 1; s++) {
+		u32 sample;
+
+		sample = group->total[PSI_AVGS][s] - group->avg_total[s];
+		/*
+		 * Due to the lockless sampling of the time buckets,
+		 * recorded time deltas can slip into the next period,
+		 * which under full pressure can result in samples in
+		 * excess of the period length.
+		 *
+		 * We don't want to report non-sensical pressures in
+		 * excess of 100%, nor do we want to drop such events
+		 * on the floor. Instead we punt any overage into the
+		 * future until pressure subsides. By doing this we
+		 * don't underreport the occurring pressure curve, we
+		 * just report it delayed by one period length.
+		 *
+		 * The error isn't cumulative. As soon as another
+		 * delta slips from a period P to P+1, by definition
+		 * it frees up its time T in P.
+		 */
+		if (sample > period)
+			sample = period;
+		group->avg_total[s] += sample;
+		calc_avgs(group->avg[s], missed_periods, sample, period);
+	}
+
+	return avg_next_update;
+}
+
+static void psi_avgs_work(struct work_struct *work)
+{
+	struct delayed_work *dwork;
+	struct psi_group *group;
+	u32 changed_states;
+	bool update_total;
+	u64 now;
+
+	dwork = to_delayed_work(work);
+	group = container_of(dwork, struct psi_group, avgs_work);
+
+	mutex_lock(&group->avgs_lock);
+
+	now = sched_clock();
+
+	collect_percpu_times(group, PSI_AVGS, &changed_states);
+	/*
+	 * If there is task activity, periodically fold the per-cpu
+	 * times and feed samples into the running averages. If things
+	 * are idle and there is no data to process, stop the clock.
+	 * Once restarted, we'll catch up the running averages in one
+	 * go - see calc_avgs() and missed_periods.
+	 */
+	if (now >= group->avg_next_update) {
+		update_triggers(group, now, &update_total, PSI_AVGS);
+		group->avg_next_update = update_averages(group, now);
+	}
+
+	if (changed_states & PSI_STATE_RESCHEDULE) {
+		schedule_delayed_work(dwork, nsecs_to_jiffies(
+				group->avg_next_update - now) + 1);
+	}
+
+	mutex_unlock(&group->avgs_lock);
+}
+
+static void init_rtpoll_triggers(struct psi_group *group, u64 now)
+{
+	struct psi_trigger *t;
+
+	list_for_each_entry(t, &group->rtpoll_triggers, node)
+		window_reset(&t->win, now,
+				group->total[PSI_POLL][t->state], 0);
+	memcpy(group->rtpoll_total, group->total[PSI_POLL],
+		   sizeof(group->rtpoll_total));
+	group->rtpoll_next_update = now + group->rtpoll_min_period;
+}
+
+/* Schedule polling if it's not already scheduled or forced. */
+static void psi_schedule_rtpoll_work(struct psi_group *group, unsigned long delay,
+				   bool force)
+{
+	struct task_struct *task;
+
+	/*
+	 * atomic_xchg should be called even when !force to provide a
+	 * full memory barrier (see the comment inside psi_rtpoll_work).
+	 */
+	if (atomic_xchg(&group->rtpoll_scheduled, 1) && !force)
+		return;
+
+	rcu_read_lock();
+
+	task = rcu_dereference(group->rtpoll_task);
+	/*
+	 * kworker might be NULL in case psi_trigger_destroy races with
+	 * psi_task_change (hotpath) which can't use locks
+	 */
+	if (likely(task))
+		mod_timer(&group->rtpoll_timer, jiffies + delay);
+	else
+		atomic_set(&group->rtpoll_scheduled, 0);
+
+	rcu_read_unlock();
+}
+
+static void psi_rtpoll_work(struct psi_group *group)
+{
+	bool force_reschedule = false;
+	u32 changed_states;
+	bool update_total;
+	u64 now;
+
+	mutex_lock(&group->rtpoll_trigger_lock);
+
+	now = sched_clock();
+
+	if (now > group->rtpoll_until) {
+		/*
+		 * We are either about to start or might stop polling if no
+		 * state change was recorded. Resetting poll_scheduled leaves
+		 * a small window for psi_group_change to sneak in and schedule
+		 * an immediate poll_work before we get to rescheduling. One
+		 * potential extra wakeup at the end of the polling window
+		 * should be negligible and polling_next_update still keeps
+		 * updates correctly on schedule.
+		 */
+		atomic_set(&group->rtpoll_scheduled, 0);
+		/*
+		 * A task change can race with the poll worker that is supposed to
+		 * report on it. To avoid missing events, ensure ordering between
+		 * poll_scheduled and the task state accesses, such that if the poll
+		 * worker misses the state update, the task change is guaranteed to
+		 * reschedule the poll worker:
+		 *
+		 * poll worker:
+		 *   atomic_set(poll_scheduled, 0)
+		 *   smp_mb()
+		 *   LOAD states
+		 *
+		 * task change:
+		 *   STORE states
+		 *   if atomic_xchg(poll_scheduled, 1) == 0:
+		 *     schedule poll worker
+		 *
+		 * The atomic_xchg() implies a full barrier.
+		 */
+		smp_mb();
+	} else {
+		/* Polling window is not over, keep rescheduling */
+		force_reschedule = true;
+	}
+
+
+	collect_percpu_times(group, PSI_POLL, &changed_states);
+
+	if (changed_states & group->rtpoll_states) {
+		/* Initialize trigger windows when entering polling mode */
+		if (now > group->rtpoll_until)
+			init_rtpoll_triggers(group, now);
+
+		/*
+		 * Keep the monitor active for at least the duration of the
+		 * minimum tracking window as long as monitor states are
+		 * changing.
+		 */
+		group->rtpoll_until = now +
+			group->rtpoll_min_period * UPDATES_PER_WINDOW;
+	}
+
+	if (now > group->rtpoll_until) {
+		group->rtpoll_next_update = ULLONG_MAX;
+		goto out;
+	}
+
+	if (now >= group->rtpoll_next_update) {
+		group->rtpoll_next_update = update_triggers(group, now, &update_total, PSI_POLL);
+		if (update_total)
+			memcpy(group->rtpoll_total, group->total[PSI_POLL],
+				   sizeof(group->rtpoll_total));
+	}
+
+	psi_schedule_rtpoll_work(group,
+		nsecs_to_jiffies(group->rtpoll_next_update - now) + 1,
+		force_reschedule);
+
+out:
+	mutex_unlock(&group->rtpoll_trigger_lock);
+}
+
+static int psi_rtpoll_worker(void *data)
+{
+	struct psi_group *group = (struct psi_group *)data;
+
+	sched_set_fifo_low(current);
+
+	while (true) {
+		wait_event_interruptible(group->rtpoll_wait,
+				atomic_cmpxchg(&group->rtpoll_wakeup, 1, 0) ||
+				kthread_should_stop());
+		if (kthread_should_stop())
+			break;
+
+		psi_rtpoll_work(group);
+	}
+	return 0;
+}
+
+static void poll_timer_fn(struct timer_list *t)
+{
+	struct psi_group *group = from_timer(group, t, rtpoll_timer);
+
+	atomic_set(&group->rtpoll_wakeup, 1);
+	wake_up_interruptible(&group->rtpoll_wait);
+}
+
+static void record_times(struct psi_group_cpu *groupc, u64 now)
+{
+	u32 delta;
+
+	delta = now - groupc->state_start;
+	groupc->state_start = now;
+
+	if (groupc->state_mask & (1 << PSI_IO_SOME)) {
+		groupc->times[PSI_IO_SOME] += delta;
+		if (groupc->state_mask & (1 << PSI_IO_FULL))
+			groupc->times[PSI_IO_FULL] += delta;
+	}
+
+	if (groupc->state_mask & (1 << PSI_MEM_SOME)) {
+		groupc->times[PSI_MEM_SOME] += delta;
+		if (groupc->state_mask & (1 << PSI_MEM_FULL))
+			groupc->times[PSI_MEM_FULL] += delta;
+	}
+
+	if (groupc->state_mask & (1 << PSI_CPU_SOME)) {
+		groupc->times[PSI_CPU_SOME] += delta;
+		if (groupc->state_mask & (1 << PSI_CPU_FULL))
+			groupc->times[PSI_CPU_FULL] += delta;
+	}
+
+	if (groupc->state_mask & (1 << PSI_NONIDLE))
+		groupc->times[PSI_NONIDLE] += delta;
+}
+
+static void psi_group_change(struct psi_group *group, int cpu,
+			     unsigned int clear, unsigned int set, u64 now,
+			     bool wake_clock)
+{
+	struct psi_group_cpu *groupc;
+	unsigned int t, m;
+	enum psi_states s;
+	u32 state_mask;
+
+	groupc = per_cpu_ptr(group->pcpu, cpu);
+
+	/*
+	 * First we update the task counts according to the state
+	 * change requested through the @clear and @set bits.
+	 *
+	 * Then if the cgroup PSI stats accounting enabled, we
+	 * assess the aggregate resource states this CPU's tasks
+	 * have been in since the last change, and account any
+	 * SOME and FULL time these may have resulted in.
+	 */
+	write_seqcount_begin(&groupc->seq);
+
+	/*
+	 * Start with TSK_ONCPU, which doesn't have a corresponding
+	 * task count - it's just a boolean flag directly encoded in
+	 * the state mask. Clear, set, or carry the current state if
+	 * no changes are requested.
+	 */
+	if (unlikely(clear & TSK_ONCPU)) {
+		state_mask = 0;
+		clear &= ~TSK_ONCPU;
+	} else if (unlikely(set & TSK_ONCPU)) {
+		state_mask = PSI_ONCPU;
+		set &= ~TSK_ONCPU;
+	} else {
+		state_mask = groupc->state_mask & PSI_ONCPU;
+	}
+
+	/*
+	 * The rest of the state mask is calculated based on the task
+	 * counts. Update those first, then construct the mask.
+	 */
+	for (t = 0, m = clear; m; m &= ~(1 << t), t++) {
+		if (!(m & (1 << t)))
+			continue;
+		if (groupc->tasks[t]) {
+			groupc->tasks[t]--;
+		} else if (!psi_bug) {
+			printk_deferred(KERN_ERR "psi: task underflow! cpu=%d t=%d tasks=[%u %u %u %u] clear=%x set=%x\n",
+					cpu, t, groupc->tasks[0],
+					groupc->tasks[1], groupc->tasks[2],
+					groupc->tasks[3], clear, set);
+			psi_bug = 1;
+		}
+	}
+
+	for (t = 0; set; set &= ~(1 << t), t++)
+		if (set & (1 << t))
+			groupc->tasks[t]++;
+
+	if (!group->enabled) {
+		/*
+		 * On the first group change after disabling PSI, conclude
+		 * the current state and flush its time. This is unlikely
+		 * to matter to the user, but aggregation (get_recent_times)
+		 * may have already incorporated the live state into times_prev;
+		 * avoid a delta sample underflow when PSI is later re-enabled.
+		 */
+		if (unlikely(groupc->state_mask & (1 << PSI_NONIDLE)))
+			record_times(groupc, now);
+
+		groupc->state_mask = state_mask;
+
+		write_seqcount_end(&groupc->seq);
+		return;
+	}
+
+	for (s = 0; s < NR_PSI_STATES; s++) {
+		if (test_state(groupc->tasks, s, state_mask & PSI_ONCPU))
+			state_mask |= (1 << s);
+	}
+
+	/*
+	 * Since we care about lost potential, a memstall is FULL
+	 * when there are no other working tasks, but also when
+	 * the CPU is actively reclaiming and nothing productive
+	 * could run even if it were runnable. So when the current
+	 * task in a cgroup is in_memstall, the corresponding groupc
+	 * on that cpu is in PSI_MEM_FULL state.
+	 */
+	if (unlikely((state_mask & PSI_ONCPU) && cpu_curr(cpu)->in_memstall))
+		state_mask |= (1 << PSI_MEM_FULL);
+
+	record_times(groupc, now);
+
+	groupc->state_mask = state_mask;
+
+	write_seqcount_end(&groupc->seq);
+
+	if (state_mask & group->rtpoll_states)
+		psi_schedule_rtpoll_work(group, 1, false);
+
+	if (wake_clock && !delayed_work_pending(&group->avgs_work))
+		schedule_delayed_work(&group->avgs_work, PSI_FREQ);
+}
+
+static inline struct psi_group *task_psi_group(struct task_struct *task)
+{
+#ifdef CONFIG_CGROUPS
+	if (static_branch_likely(&psi_cgroups_enabled))
+		return cgroup_psi(task_dfl_cgroup(task));
+#endif
+	return &psi_system;
+}
+
+static void psi_flags_change(struct task_struct *task, int clear, int set)
+{
+	if (((task->psi_flags & set) ||
+	     (task->psi_flags & clear) != clear) &&
+	    !psi_bug) {
+		printk_deferred(KERN_ERR "psi: inconsistent task state! task=%d:%s cpu=%d psi_flags=%x clear=%x set=%x\n",
+				task->pid, task->comm, task_cpu(task),
+				task->psi_flags, clear, set);
+		psi_bug = 1;
+	}
+
+	task->psi_flags &= ~clear;
+	task->psi_flags |= set;
+}
+
+void psi_task_change(struct task_struct *task, int clear, int set)
+{
+	int cpu = task_cpu(task);
+	struct psi_group *group;
+	u64 now;
+
+	if (!task->pid)
+		return;
+
+	psi_flags_change(task, clear, set);
+
+	now = cpu_clock(cpu);
+
+	group = task_psi_group(task);
+	do {
+		psi_group_change(group, cpu, clear, set, now, true);
+	} while ((group = group->parent));
+}
+
+void psi_task_switch(struct task_struct *prev, struct task_struct *next,
+		     bool sleep)
+{
+	struct psi_group *group, *common = NULL;
+	int cpu = task_cpu(prev);
+	u64 now = cpu_clock(cpu);
+
+	if (next->pid) {
+		psi_flags_change(next, 0, TSK_ONCPU);
+		/*
+		 * Set TSK_ONCPU on @next's cgroups. If @next shares any
+		 * ancestors with @prev, those will already have @prev's
+		 * TSK_ONCPU bit set, and we can stop the iteration there.
+		 */
+		group = task_psi_group(next);
+		do {
+			if (per_cpu_ptr(group->pcpu, cpu)->state_mask &
+			    PSI_ONCPU) {
+				common = group;
+				break;
+			}
+
+			psi_group_change(group, cpu, 0, TSK_ONCPU, now, true);
+		} while ((group = group->parent));
+	}
+
+	if (prev->pid) {
+		int clear = TSK_ONCPU, set = 0;
+		bool wake_clock = true;
+
+		/*
+		 * When we're going to sleep, psi_dequeue() lets us
+		 * handle TSK_RUNNING, TSK_MEMSTALL_RUNNING and
+		 * TSK_IOWAIT here, where we can combine it with
+		 * TSK_ONCPU and save walking common ancestors twice.
+		 */
+		if (sleep) {
+			clear |= TSK_RUNNING;
+			if (prev->in_memstall)
+				clear |= TSK_MEMSTALL_RUNNING;
+			if (prev->in_iowait)
+				set |= TSK_IOWAIT;
+
+			/*
+			 * Periodic aggregation shuts off if there is a period of no
+			 * task changes, so we wake it back up if necessary. However,
+			 * don't do this if the task change is the aggregation worker
+			 * itself going to sleep, or we'll ping-pong forever.
+			 */
+			if (unlikely((prev->flags & PF_WQ_WORKER) &&
+				     wq_worker_last_func(prev) == psi_avgs_work))
+				wake_clock = false;
+		}
+
+		psi_flags_change(prev, clear, set);
+
+		group = task_psi_group(prev);
+		do {
+			if (group == common)
+				break;
+			psi_group_change(group, cpu, clear, set, now, wake_clock);
+		} while ((group = group->parent));
+
+		/*
+		 * TSK_ONCPU is handled up to the common ancestor. If there are
+		 * any other differences between the two tasks (e.g. prev goes
+		 * to sleep, or only one task is memstall), finish propagating
+		 * those differences all the way up to the root.
+		 */
+		if ((prev->psi_flags ^ next->psi_flags) & ~TSK_ONCPU) {
+			clear &= ~TSK_ONCPU;
+			for (; group; group = group->parent)
+				psi_group_change(group, cpu, clear, set, now, wake_clock);
+		}
+	}
+}
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+void psi_account_irqtime(struct task_struct *task, u32 delta)
+{
+	int cpu = task_cpu(task);
+	struct psi_group *group;
+	struct psi_group_cpu *groupc;
+	u64 now;
+
+	if (!task->pid)
+		return;
+
+	now = cpu_clock(cpu);
+
+	group = task_psi_group(task);
+	do {
+		if (!group->enabled)
+			continue;
+
+		groupc = per_cpu_ptr(group->pcpu, cpu);
+
+		write_seqcount_begin(&groupc->seq);
+
+		record_times(groupc, now);
+		groupc->times[PSI_IRQ_FULL] += delta;
+
+		write_seqcount_end(&groupc->seq);
+
+		if (group->rtpoll_states & (1 << PSI_IRQ_FULL))
+			psi_schedule_rtpoll_work(group, 1, false);
+	} while ((group = group->parent));
+}
+#endif
+
+/**
+ * psi_memstall_enter - mark the beginning of a memory stall section
+ * @flags: flags to handle nested sections
+ *
+ * Marks the calling task as being stalled due to a lack of memory,
+ * such as waiting for a refault or performing reclaim.
+ */
+void psi_memstall_enter(unsigned long *flags)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (static_branch_likely(&psi_disabled))
+		return;
+
+	*flags = current->in_memstall;
+	if (*flags)
+		return;
+	/*
+	 * in_memstall setting & accounting needs to be atomic wrt
+	 * changes to the task's scheduling state, otherwise we can
+	 * race with CPU migration.
+	 */
+	rq = this_rq_lock_irq(&rf);
+
+	current->in_memstall = 1;
+	psi_task_change(current, 0, TSK_MEMSTALL | TSK_MEMSTALL_RUNNING);
+
+	rq_unlock_irq(rq, &rf);
+}
+EXPORT_SYMBOL_GPL(psi_memstall_enter);
+
+/**
+ * psi_memstall_leave - mark the end of an memory stall section
+ * @flags: flags to handle nested memdelay sections
+ *
+ * Marks the calling task as no longer stalled due to lack of memory.
+ */
+void psi_memstall_leave(unsigned long *flags)
+{
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (static_branch_likely(&psi_disabled))
+		return;
+
+	if (*flags)
+		return;
+	/*
+	 * in_memstall clearing & accounting needs to be atomic wrt
+	 * changes to the task's scheduling state, otherwise we could
+	 * race with CPU migration.
+	 */
+	rq = this_rq_lock_irq(&rf);
+
+	current->in_memstall = 0;
+	psi_task_change(current, TSK_MEMSTALL | TSK_MEMSTALL_RUNNING, 0);
+
+	rq_unlock_irq(rq, &rf);
+}
+EXPORT_SYMBOL_GPL(psi_memstall_leave);
+
+#ifdef CONFIG_CGROUPS
+int psi_cgroup_alloc(struct cgroup *cgroup)
+{
+	if (!static_branch_likely(&psi_cgroups_enabled))
+		return 0;
+
+	cgroup->psi = kzalloc(sizeof(struct psi_group), GFP_KERNEL);
+	if (!cgroup->psi)
+		return -ENOMEM;
+
+	cgroup->psi->pcpu = alloc_percpu(struct psi_group_cpu);
+	if (!cgroup->psi->pcpu) {
+		kfree(cgroup->psi);
+		return -ENOMEM;
+	}
+	group_init(cgroup->psi);
+	cgroup->psi->parent = cgroup_psi(cgroup_parent(cgroup));
+	return 0;
+}
+
+void psi_cgroup_free(struct cgroup *cgroup)
+{
+	if (!static_branch_likely(&psi_cgroups_enabled))
+		return;
+
+	cancel_delayed_work_sync(&cgroup->psi->avgs_work);
+	free_percpu(cgroup->psi->pcpu);
+	/* All triggers must be removed by now */
+	WARN_ONCE(cgroup->psi->rtpoll_states, "psi: trigger leak\n");
+	kfree(cgroup->psi);
+}
+
+/**
+ * cgroup_move_task - move task to a different cgroup
+ * @task: the task
+ * @to: the target css_set
+ *
+ * Move task to a new cgroup and safely migrate its associated stall
+ * state between the different groups.
+ *
+ * This function acquires the task's rq lock to lock out concurrent
+ * changes to the task's scheduling state and - in case the task is
+ * running - concurrent changes to its stall state.
+ */
+void cgroup_move_task(struct task_struct *task, struct css_set *to)
+{
+	unsigned int task_flags;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	if (!static_branch_likely(&psi_cgroups_enabled)) {
+		/*
+		 * Lame to do this here, but the scheduler cannot be locked
+		 * from the outside, so we move cgroups from inside sched/.
+		 */
+		rcu_assign_pointer(task->cgroups, to);
+		return;
+	}
+
+	rq = task_rq_lock(task, &rf);
+
+	/*
+	 * We may race with schedule() dropping the rq lock between
+	 * deactivating prev and switching to next. Because the psi
+	 * updates from the deactivation are deferred to the switch
+	 * callback to save cgroup tree updates, the task's scheduling
+	 * state here is not coherent with its psi state:
+	 *
+	 * schedule()                   cgroup_move_task()
+	 *   rq_lock()
+	 *   deactivate_task()
+	 *     p->on_rq = 0
+	 *     psi_dequeue() // defers TSK_RUNNING & TSK_IOWAIT updates
+	 *   pick_next_task()
+	 *     rq_unlock()
+	 *                                rq_lock()
+	 *                                psi_task_change() // old cgroup
+	 *                                task->cgroups = to
+	 *                                psi_task_change() // new cgroup
+	 *                                rq_unlock()
+	 *     rq_lock()
+	 *   psi_sched_switch() // does deferred updates in new cgroup
+	 *
+	 * Don't rely on the scheduling state. Use psi_flags instead.
+	 */
+	task_flags = task->psi_flags;
+
+	if (task_flags)
+		psi_task_change(task, task_flags, 0);
+
+	/* See comment above */
+	rcu_assign_pointer(task->cgroups, to);
+
+	if (task_flags)
+		psi_task_change(task, 0, task_flags);
+
+	task_rq_unlock(rq, task, &rf);
+}
+
+void psi_cgroup_restart(struct psi_group *group)
+{
+	int cpu;
+
+	/*
+	 * After we disable psi_group->enabled, we don't actually
+	 * stop percpu tasks accounting in each psi_group_cpu,
+	 * instead only stop test_state() loop, record_times()
+	 * and averaging worker, see psi_group_change() for details.
+	 *
+	 * When disable cgroup PSI, this function has nothing to sync
+	 * since cgroup pressure files are hidden and percpu psi_group_cpu
+	 * would see !psi_group->enabled and only do task accounting.
+	 *
+	 * When re-enable cgroup PSI, this function use psi_group_change()
+	 * to get correct state mask from test_state() loop on tasks[],
+	 * and restart groupc->state_start from now, use .clear = .set = 0
+	 * here since no task status really changed.
+	 */
+	if (!group->enabled)
+		return;
+
+	for_each_possible_cpu(cpu) {
+		struct rq *rq = cpu_rq(cpu);
+		struct rq_flags rf;
+		u64 now;
+
+		rq_lock_irq(rq, &rf);
+		now = cpu_clock(cpu);
+		psi_group_change(group, cpu, 0, 0, now, true);
+		rq_unlock_irq(rq, &rf);
+	}
+}
+#endif /* CONFIG_CGROUPS */
+
+int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
+{
+	bool only_full = false;
+	int full;
+	u64 now;
+
+	if (static_branch_likely(&psi_disabled))
+		return -EOPNOTSUPP;
+
+	/* Update averages before reporting them */
+	mutex_lock(&group->avgs_lock);
+	now = sched_clock();
+	collect_percpu_times(group, PSI_AVGS, NULL);
+	if (now >= group->avg_next_update)
+		group->avg_next_update = update_averages(group, now);
+	mutex_unlock(&group->avgs_lock);
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	only_full = res == PSI_IRQ;
+#endif
+
+	for (full = 0; full < 2 - only_full; full++) {
+		unsigned long avg[3] = { 0, };
+		u64 total = 0;
+		int w;
+
+		/* CPU FULL is undefined at the system level */
+		if (!(group == &psi_system && res == PSI_CPU && full)) {
+			for (w = 0; w < 3; w++)
+				avg[w] = group->avg[res * 2 + full][w];
+			total = div_u64(group->total[PSI_AVGS][res * 2 + full],
+					NSEC_PER_USEC);
+		}
+
+		seq_printf(m, "%s avg10=%lu.%02lu avg60=%lu.%02lu avg300=%lu.%02lu total=%llu\n",
+			   full || only_full ? "full" : "some",
+			   LOAD_INT(avg[0]), LOAD_FRAC(avg[0]),
+			   LOAD_INT(avg[1]), LOAD_FRAC(avg[1]),
+			   LOAD_INT(avg[2]), LOAD_FRAC(avg[2]),
+			   total);
+	}
+
+	return 0;
+}
+
+struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
+				       enum psi_res res, struct file *file,
+				       struct kernfs_open_file *of)
+{
+	struct psi_trigger *t;
+	enum psi_states state;
+	u32 threshold_us;
+	bool privileged;
+	u32 window_us;
+
+	if (static_branch_likely(&psi_disabled))
+		return ERR_PTR(-EOPNOTSUPP);
+
+	/*
+	 * Checking the privilege here on file->f_cred implies that a privileged user
+	 * could open the file and delegate the write to an unprivileged one.
+	 */
+	privileged = cap_raised(file->f_cred->cap_effective, CAP_SYS_RESOURCE);
+
+	if (sscanf(buf, "some %u %u", &threshold_us, &window_us) == 2)
+		state = PSI_IO_SOME + res * 2;
+	else if (sscanf(buf, "full %u %u", &threshold_us, &window_us) == 2)
+		state = PSI_IO_FULL + res * 2;
+	else
+		return ERR_PTR(-EINVAL);
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	if (res == PSI_IRQ && --state != PSI_IRQ_FULL)
+		return ERR_PTR(-EINVAL);
+#endif
+
+	if (state >= PSI_NONIDLE)
+		return ERR_PTR(-EINVAL);
+
+	if (window_us < WINDOW_MIN_US ||
+		window_us > WINDOW_MAX_US)
+		return ERR_PTR(-EINVAL);
+
+	/*
+	 * Unprivileged users can only use 2s windows so that averages aggregation
+	 * work is used, and no RT threads need to be spawned.
+	 */
+	if (!privileged && window_us % 2000000)
+		return ERR_PTR(-EINVAL);
+
+	/* Check threshold */
+	if (threshold_us == 0 || threshold_us > window_us)
+		return ERR_PTR(-EINVAL);
+
+	t = kmalloc(sizeof(*t), GFP_KERNEL);
+	if (!t)
+		return ERR_PTR(-ENOMEM);
+
+	t->group = group;
+	t->state = state;
+	t->threshold = threshold_us * NSEC_PER_USEC;
+	t->win.size = window_us * NSEC_PER_USEC;
+	window_reset(&t->win, sched_clock(),
+			group->total[PSI_POLL][t->state], 0);
+
+	t->event = 0;
+	t->last_event_time = 0;
+	t->of = of;
+	if (!of)
+		init_waitqueue_head(&t->event_wait);
+	t->pending_event = false;
+	t->aggregator = privileged ? PSI_POLL : PSI_AVGS;
+
+	if (privileged) {
+		mutex_lock(&group->rtpoll_trigger_lock);
+
+		if (!rcu_access_pointer(group->rtpoll_task)) {
+			struct task_struct *task;
+
+			task = kthread_create(psi_rtpoll_worker, group, "psimon");
+			if (IS_ERR(task)) {
+				kfree(t);
+				mutex_unlock(&group->rtpoll_trigger_lock);
+				return ERR_CAST(task);
+			}
+			atomic_set(&group->rtpoll_wakeup, 0);
+			wake_up_process(task);
+			rcu_assign_pointer(group->rtpoll_task, task);
+		}
+
+		list_add(&t->node, &group->rtpoll_triggers);
+		group->rtpoll_min_period = min(group->rtpoll_min_period,
+			div_u64(t->win.size, UPDATES_PER_WINDOW));
+		group->rtpoll_nr_triggers[t->state]++;
+		group->rtpoll_states |= (1 << t->state);
+
+		mutex_unlock(&group->rtpoll_trigger_lock);
+	} else {
+		mutex_lock(&group->avgs_lock);
+
+		list_add(&t->node, &group->avg_triggers);
+		group->avg_nr_triggers[t->state]++;
+
+		mutex_unlock(&group->avgs_lock);
+	}
+	return t;
+}
+
+void psi_trigger_destroy(struct psi_trigger *t)
+{
+	struct psi_group *group;
+	struct task_struct *task_to_destroy = NULL;
+
+	/*
+	 * We do not check psi_disabled since it might have been disabled after
+	 * the trigger got created.
+	 */
+	if (!t)
+		return;
+
+	group = t->group;
+	/*
+	 * Wakeup waiters to stop polling and clear the queue to prevent it from
+	 * being accessed later. Can happen if cgroup is deleted from under a
+	 * polling process.
+	 */
+	if (t->of)
+		kernfs_notify(t->of->kn);
+	else
+		wake_up_interruptible(&t->event_wait);
+
+	if (t->aggregator == PSI_AVGS) {
+		mutex_lock(&group->avgs_lock);
+		if (!list_empty(&t->node)) {
+			list_del(&t->node);
+			group->avg_nr_triggers[t->state]--;
+		}
+		mutex_unlock(&group->avgs_lock);
+	} else {
+		mutex_lock(&group->rtpoll_trigger_lock);
+		if (!list_empty(&t->node)) {
+			struct psi_trigger *tmp;
+			u64 period = ULLONG_MAX;
+
+			list_del(&t->node);
+			group->rtpoll_nr_triggers[t->state]--;
+			if (!group->rtpoll_nr_triggers[t->state])
+				group->rtpoll_states &= ~(1 << t->state);
+			/* reset min update period for the remaining triggers */
+			list_for_each_entry(tmp, &group->rtpoll_triggers, node)
+				period = min(period, div_u64(tmp->win.size,
+						UPDATES_PER_WINDOW));
+			group->rtpoll_min_period = period;
+			/* Destroy rtpoll_task when the last trigger is destroyed */
+			if (group->rtpoll_states == 0) {
+				group->rtpoll_until = 0;
+				task_to_destroy = rcu_dereference_protected(
+						group->rtpoll_task,
+						lockdep_is_held(&group->rtpoll_trigger_lock));
+				rcu_assign_pointer(group->rtpoll_task, NULL);
+				del_timer(&group->rtpoll_timer);
+			}
+		}
+		mutex_unlock(&group->rtpoll_trigger_lock);
+	}
+
+	/*
+	 * Wait for psi_schedule_rtpoll_work RCU to complete its read-side
+	 * critical section before destroying the trigger and optionally the
+	 * rtpoll_task.
+	 */
+	synchronize_rcu();
+	/*
+	 * Stop kthread 'psimon' after releasing rtpoll_trigger_lock to prevent
+	 * a deadlock while waiting for psi_rtpoll_work to acquire
+	 * rtpoll_trigger_lock
+	 */
+	if (task_to_destroy) {
+		/*
+		 * After the RCU grace period has expired, the worker
+		 * can no longer be found through group->rtpoll_task.
+		 */
+		kthread_stop(task_to_destroy);
+		atomic_set(&group->rtpoll_scheduled, 0);
+	}
+	kfree(t);
+}
+
+__poll_t psi_trigger_poll(void **trigger_ptr,
+				struct file *file, poll_table *wait)
+{
+	__poll_t ret = DEFAULT_POLLMASK;
+	struct psi_trigger *t;
+
+	if (static_branch_likely(&psi_disabled))
+		return DEFAULT_POLLMASK | EPOLLERR | EPOLLPRI;
+
+	t = smp_load_acquire(trigger_ptr);
+	if (!t)
+		return DEFAULT_POLLMASK | EPOLLERR | EPOLLPRI;
+
+	if (t->of)
+		kernfs_generic_poll(t->of, wait);
+	else
+		poll_wait(file, &t->event_wait, wait);
+
+	if (cmpxchg(&t->event, 1, 0) == 1)
+		ret |= EPOLLPRI;
+
+	return ret;
+}
+
+#ifdef CONFIG_PROC_FS
+static int psi_io_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_IO);
+}
+
+static int psi_memory_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_MEM);
+}
+
+static int psi_cpu_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_CPU);
+}
+
+static int psi_io_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, psi_io_show, NULL);
+}
+
+static int psi_memory_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, psi_memory_show, NULL);
+}
+
+static int psi_cpu_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, psi_cpu_show, NULL);
+}
+
+static ssize_t psi_write(struct file *file, const char __user *user_buf,
+			 size_t nbytes, enum psi_res res)
+{
+	char buf[32];
+	size_t buf_size;
+	struct seq_file *seq;
+	struct psi_trigger *new;
+
+	if (static_branch_likely(&psi_disabled))
+		return -EOPNOTSUPP;
+
+	if (!nbytes)
+		return -EINVAL;
+
+	buf_size = min(nbytes, sizeof(buf));
+	if (copy_from_user(buf, user_buf, buf_size))
+		return -EFAULT;
+
+	buf[buf_size - 1] = '\0';
+
+	seq = file->private_data;
+
+	/* Take seq->lock to protect seq->private from concurrent writes */
+	mutex_lock(&seq->lock);
+
+	/* Allow only one trigger per file descriptor */
+	if (seq->private) {
+		mutex_unlock(&seq->lock);
+		return -EBUSY;
+	}
+
+	new = psi_trigger_create(&psi_system, buf, res, file, NULL);
+	if (IS_ERR(new)) {
+		mutex_unlock(&seq->lock);
+		return PTR_ERR(new);
+	}
+
+	smp_store_release(&seq->private, new);
+	mutex_unlock(&seq->lock);
+
+	return nbytes;
+}
+
+static ssize_t psi_io_write(struct file *file, const char __user *user_buf,
+			    size_t nbytes, loff_t *ppos)
+{
+	return psi_write(file, user_buf, nbytes, PSI_IO);
+}
+
+static ssize_t psi_memory_write(struct file *file, const char __user *user_buf,
+				size_t nbytes, loff_t *ppos)
+{
+	return psi_write(file, user_buf, nbytes, PSI_MEM);
+}
+
+static ssize_t psi_cpu_write(struct file *file, const char __user *user_buf,
+			     size_t nbytes, loff_t *ppos)
+{
+	return psi_write(file, user_buf, nbytes, PSI_CPU);
+}
+
+static __poll_t psi_fop_poll(struct file *file, poll_table *wait)
+{
+	struct seq_file *seq = file->private_data;
+
+	return psi_trigger_poll(&seq->private, file, wait);
+}
+
+static int psi_fop_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq = file->private_data;
+
+	psi_trigger_destroy(seq->private);
+	return single_release(inode, file);
+}
+
+static const struct proc_ops psi_io_proc_ops = {
+	.proc_open	= psi_io_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_write	= psi_io_write,
+	.proc_poll	= psi_fop_poll,
+	.proc_release	= psi_fop_release,
+};
+
+static const struct proc_ops psi_memory_proc_ops = {
+	.proc_open	= psi_memory_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_write	= psi_memory_write,
+	.proc_poll	= psi_fop_poll,
+	.proc_release	= psi_fop_release,
+};
+
+static const struct proc_ops psi_cpu_proc_ops = {
+	.proc_open	= psi_cpu_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_write	= psi_cpu_write,
+	.proc_poll	= psi_fop_poll,
+	.proc_release	= psi_fop_release,
+};
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+static int psi_irq_show(struct seq_file *m, void *v)
+{
+	return psi_show(m, &psi_system, PSI_IRQ);
+}
+
+static int psi_irq_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, psi_irq_show, NULL);
+}
+
+static ssize_t psi_irq_write(struct file *file, const char __user *user_buf,
+			     size_t nbytes, loff_t *ppos)
+{
+	return psi_write(file, user_buf, nbytes, PSI_IRQ);
+}
+
+static const struct proc_ops psi_irq_proc_ops = {
+	.proc_open	= psi_irq_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_write	= psi_irq_write,
+	.proc_poll	= psi_fop_poll,
+	.proc_release	= psi_fop_release,
+};
+#endif
+
+static int __init psi_proc_init(void)
+{
+	if (psi_enable) {
+		proc_mkdir("pressure", NULL);
+		proc_create("pressure/io", 0666, NULL, &psi_io_proc_ops);
+		proc_create("pressure/memory", 0666, NULL, &psi_memory_proc_ops);
+		proc_create("pressure/cpu", 0666, NULL, &psi_cpu_proc_ops);
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+		proc_create("pressure/irq", 0666, NULL, &psi_irq_proc_ops);
+#endif
+	}
+	return 0;
+}
+module_init(psi_proc_init);
+
+#endif /* CONFIG_PROC_FS */
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
new file mode 100644
index 000000000..76bafa8d3
--- /dev/null
+++ b/kernel/sched/rt.c
@@ -0,0 +1,3068 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
+ * policies)
+ */
+
+int sched_rr_timeslice = RR_TIMESLICE;
+/* More than 4 hours if BW_SHIFT equals 20. */
+static const u64 max_rt_runtime = MAX_BW;
+
+static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
+
+struct rt_bandwidth def_rt_bandwidth;
+
+/*
+ * period over which we measure -rt task CPU usage in us.
+ * default: 1s
+ */
+unsigned int sysctl_sched_rt_period = 1000000;
+
+/*
+ * part of the period that we allow rt tasks to run in us.
+ * default: 0.95s
+ */
+int sysctl_sched_rt_runtime = 950000;
+
+#ifdef CONFIG_SYSCTL
+static int sysctl_sched_rr_timeslice = (MSEC_PER_SEC * RR_TIMESLICE) / HZ;
+static int sched_rt_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
+static int sched_rr_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos);
+static struct ctl_table sched_rt_sysctls[] = {
+	{
+		.procname       = "sched_rt_period_us",
+		.data           = &sysctl_sched_rt_period,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sched_rt_handler,
+	},
+	{
+		.procname       = "sched_rt_runtime_us",
+		.data           = &sysctl_sched_rt_runtime,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = sched_rt_handler,
+	},
+	{
+		.procname       = "sched_rr_timeslice_ms",
+		.data           = &sysctl_sched_rr_timeslice,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = sched_rr_handler,
+	},
+	{}
+};
+
+static int __init sched_rt_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_rt_sysctls);
+	return 0;
+}
+late_initcall(sched_rt_sysctl_init);
+#endif
+
+static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
+{
+	struct rt_bandwidth *rt_b =
+		container_of(timer, struct rt_bandwidth, rt_period_timer);
+	int idle = 0;
+	int overrun;
+
+	raw_spin_lock(&rt_b->rt_runtime_lock);
+	for (;;) {
+		overrun = hrtimer_forward_now(timer, rt_b->rt_period);
+		if (!overrun)
+			break;
+
+		raw_spin_unlock(&rt_b->rt_runtime_lock);
+		idle = do_sched_rt_period_timer(rt_b, overrun);
+		raw_spin_lock(&rt_b->rt_runtime_lock);
+	}
+	if (idle)
+		rt_b->rt_period_active = 0;
+	raw_spin_unlock(&rt_b->rt_runtime_lock);
+
+	return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
+}
+
+void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
+{
+	rt_b->rt_period = ns_to_ktime(period);
+	rt_b->rt_runtime = runtime;
+
+	raw_spin_lock_init(&rt_b->rt_runtime_lock);
+
+	hrtimer_init(&rt_b->rt_period_timer, CLOCK_MONOTONIC,
+		     HRTIMER_MODE_REL_HARD);
+	rt_b->rt_period_timer.function = sched_rt_period_timer;
+}
+
+static inline void do_start_rt_bandwidth(struct rt_bandwidth *rt_b)
+{
+	raw_spin_lock(&rt_b->rt_runtime_lock);
+	if (!rt_b->rt_period_active) {
+		rt_b->rt_period_active = 1;
+		/*
+		 * SCHED_DEADLINE updates the bandwidth, as a run away
+		 * RT task with a DL task could hog a CPU. But DL does
+		 * not reset the period. If a deadline task was running
+		 * without an RT task running, it can cause RT tasks to
+		 * throttle when they start up. Kick the timer right away
+		 * to update the period.
+		 */
+		hrtimer_forward_now(&rt_b->rt_period_timer, ns_to_ktime(0));
+		hrtimer_start_expires(&rt_b->rt_period_timer,
+				      HRTIMER_MODE_ABS_PINNED_HARD);
+	}
+	raw_spin_unlock(&rt_b->rt_runtime_lock);
+}
+
+static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
+{
+	if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
+		return;
+
+	do_start_rt_bandwidth(rt_b);
+}
+
+void init_rt_rq(struct rt_rq *rt_rq)
+{
+	struct rt_prio_array *array;
+	int i;
+
+	array = &rt_rq->active;
+	for (i = 0; i < MAX_RT_PRIO; i++) {
+		INIT_LIST_HEAD(array->queue + i);
+		__clear_bit(i, array->bitmap);
+	}
+	/* delimiter for bitsearch: */
+	__set_bit(MAX_RT_PRIO, array->bitmap);
+
+#if defined CONFIG_SMP
+	rt_rq->highest_prio.curr = MAX_RT_PRIO-1;
+	rt_rq->highest_prio.next = MAX_RT_PRIO-1;
+	rt_rq->rt_nr_migratory = 0;
+	rt_rq->overloaded = 0;
+	plist_head_init(&rt_rq->pushable_tasks);
+#endif /* CONFIG_SMP */
+	/* We start is dequeued state, because no RT tasks are queued */
+	rt_rq->rt_queued = 0;
+
+	rt_rq->rt_time = 0;
+	rt_rq->rt_throttled = 0;
+	rt_rq->rt_runtime = 0;
+	raw_spin_lock_init(&rt_rq->rt_runtime_lock);
+}
+
+#ifdef CONFIG_RT_GROUP_SCHED
+static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
+{
+	hrtimer_cancel(&rt_b->rt_period_timer);
+}
+
+#define rt_entity_is_task(rt_se) (!(rt_se)->my_q)
+
+static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
+{
+#ifdef CONFIG_SCHED_DEBUG
+	WARN_ON_ONCE(!rt_entity_is_task(rt_se));
+#endif
+	return container_of(rt_se, struct task_struct, rt);
+}
+
+static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+{
+	return rt_rq->rq;
+}
+
+static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
+{
+	return rt_se->rt_rq;
+}
+
+static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se)
+{
+	struct rt_rq *rt_rq = rt_se->rt_rq;
+
+	return rt_rq->rq;
+}
+
+void unregister_rt_sched_group(struct task_group *tg)
+{
+	if (tg->rt_se)
+		destroy_rt_bandwidth(&tg->rt_bandwidth);
+
+}
+
+void free_rt_sched_group(struct task_group *tg)
+{
+	int i;
+
+	for_each_possible_cpu(i) {
+		if (tg->rt_rq)
+			kfree(tg->rt_rq[i]);
+		if (tg->rt_se)
+			kfree(tg->rt_se[i]);
+	}
+
+	kfree(tg->rt_rq);
+	kfree(tg->rt_se);
+}
+
+void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
+		struct sched_rt_entity *rt_se, int cpu,
+		struct sched_rt_entity *parent)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	rt_rq->highest_prio.curr = MAX_RT_PRIO-1;
+	rt_rq->rt_nr_boosted = 0;
+	rt_rq->rq = rq;
+	rt_rq->tg = tg;
+
+	tg->rt_rq[cpu] = rt_rq;
+	tg->rt_se[cpu] = rt_se;
+
+	if (!rt_se)
+		return;
+
+	if (!parent)
+		rt_se->rt_rq = &rq->rt;
+	else
+		rt_se->rt_rq = parent->my_q;
+
+	rt_se->my_q = rt_rq;
+	rt_se->parent = parent;
+	INIT_LIST_HEAD(&rt_se->run_list);
+}
+
+int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
+{
+	struct rt_rq *rt_rq;
+	struct sched_rt_entity *rt_se;
+	int i;
+
+	tg->rt_rq = kcalloc(nr_cpu_ids, sizeof(rt_rq), GFP_KERNEL);
+	if (!tg->rt_rq)
+		goto err;
+	tg->rt_se = kcalloc(nr_cpu_ids, sizeof(rt_se), GFP_KERNEL);
+	if (!tg->rt_se)
+		goto err;
+
+	init_rt_bandwidth(&tg->rt_bandwidth,
+			ktime_to_ns(def_rt_bandwidth.rt_period), 0);
+
+	for_each_possible_cpu(i) {
+		rt_rq = kzalloc_node(sizeof(struct rt_rq),
+				     GFP_KERNEL, cpu_to_node(i));
+		if (!rt_rq)
+			goto err;
+
+		rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
+				     GFP_KERNEL, cpu_to_node(i));
+		if (!rt_se)
+			goto err_free_rq;
+
+		init_rt_rq(rt_rq);
+		rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
+		init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
+	}
+
+	return 1;
+
+err_free_rq:
+	kfree(rt_rq);
+err:
+	return 0;
+}
+
+#else /* CONFIG_RT_GROUP_SCHED */
+
+#define rt_entity_is_task(rt_se) (1)
+
+static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
+{
+	return container_of(rt_se, struct task_struct, rt);
+}
+
+static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+{
+	return container_of(rt_rq, struct rq, rt);
+}
+
+static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se)
+{
+	struct task_struct *p = rt_task_of(rt_se);
+
+	return task_rq(p);
+}
+
+static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
+{
+	struct rq *rq = rq_of_rt_se(rt_se);
+
+	return &rq->rt;
+}
+
+void unregister_rt_sched_group(struct task_group *tg) { }
+
+void free_rt_sched_group(struct task_group *tg) { }
+
+int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
+{
+	return 1;
+}
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_SMP
+
+static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev)
+{
+	/* Try to pull RT tasks here if we lower this rq's prio */
+	return rq->online && rq->rt.highest_prio.curr > prev->prio;
+}
+
+static inline int rt_overloaded(struct rq *rq)
+{
+	return atomic_read(&rq->rd->rto_count);
+}
+
+static inline void rt_set_overload(struct rq *rq)
+{
+	if (!rq->online)
+		return;
+
+	cpumask_set_cpu(rq->cpu, rq->rd->rto_mask);
+	/*
+	 * Make sure the mask is visible before we set
+	 * the overload count. That is checked to determine
+	 * if we should look at the mask. It would be a shame
+	 * if we looked at the mask, but the mask was not
+	 * updated yet.
+	 *
+	 * Matched by the barrier in pull_rt_task().
+	 */
+	smp_wmb();
+	atomic_inc(&rq->rd->rto_count);
+}
+
+static inline void rt_clear_overload(struct rq *rq)
+{
+	if (!rq->online)
+		return;
+
+	/* the order here really doesn't matter */
+	atomic_dec(&rq->rd->rto_count);
+	cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
+}
+
+static void update_rt_migration(struct rt_rq *rt_rq)
+{
+	if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) {
+		if (!rt_rq->overloaded) {
+			rt_set_overload(rq_of_rt_rq(rt_rq));
+			rt_rq->overloaded = 1;
+		}
+	} else if (rt_rq->overloaded) {
+		rt_clear_overload(rq_of_rt_rq(rt_rq));
+		rt_rq->overloaded = 0;
+	}
+}
+
+static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	struct task_struct *p;
+
+	if (!rt_entity_is_task(rt_se))
+		return;
+
+	p = rt_task_of(rt_se);
+	rt_rq = &rq_of_rt_rq(rt_rq)->rt;
+
+	rt_rq->rt_nr_total++;
+	if (p->nr_cpus_allowed > 1)
+		rt_rq->rt_nr_migratory++;
+
+	update_rt_migration(rt_rq);
+}
+
+static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	struct task_struct *p;
+
+	if (!rt_entity_is_task(rt_se))
+		return;
+
+	p = rt_task_of(rt_se);
+	rt_rq = &rq_of_rt_rq(rt_rq)->rt;
+
+	rt_rq->rt_nr_total--;
+	if (p->nr_cpus_allowed > 1)
+		rt_rq->rt_nr_migratory--;
+
+	update_rt_migration(rt_rq);
+}
+
+static inline int has_pushable_tasks(struct rq *rq)
+{
+	return !plist_head_empty(&rq->rt.pushable_tasks);
+}
+
+static DEFINE_PER_CPU(struct balance_callback, rt_push_head);
+static DEFINE_PER_CPU(struct balance_callback, rt_pull_head);
+
+static void push_rt_tasks(struct rq *);
+static void pull_rt_task(struct rq *);
+
+static inline void rt_queue_push_tasks(struct rq *rq)
+{
+	if (!has_pushable_tasks(rq))
+		return;
+
+	queue_balance_callback(rq, &per_cpu(rt_push_head, rq->cpu), push_rt_tasks);
+}
+
+static inline void rt_queue_pull_task(struct rq *rq)
+{
+	queue_balance_callback(rq, &per_cpu(rt_pull_head, rq->cpu), pull_rt_task);
+}
+
+static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+	plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
+	plist_node_init(&p->pushable_tasks, p->prio);
+	plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks);
+
+	/* Update the highest prio pushable task */
+	if (p->prio < rq->rt.highest_prio.next)
+		rq->rt.highest_prio.next = p->prio;
+}
+
+static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+	plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
+
+	/* Update the new highest prio pushable task */
+	if (has_pushable_tasks(rq)) {
+		p = plist_first_entry(&rq->rt.pushable_tasks,
+				      struct task_struct, pushable_tasks);
+		rq->rt.highest_prio.next = p->prio;
+	} else {
+		rq->rt.highest_prio.next = MAX_RT_PRIO-1;
+	}
+}
+
+#else
+
+static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
+{
+}
+
+static inline
+void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+}
+
+static inline
+void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+}
+
+static inline void rt_queue_push_tasks(struct rq *rq)
+{
+}
+#endif /* CONFIG_SMP */
+
+static void enqueue_top_rt_rq(struct rt_rq *rt_rq);
+static void dequeue_top_rt_rq(struct rt_rq *rt_rq, unsigned int count);
+
+static inline int on_rt_rq(struct sched_rt_entity *rt_se)
+{
+	return rt_se->on_rq;
+}
+
+#ifdef CONFIG_UCLAMP_TASK
+/*
+ * Verify the fitness of task @p to run on @cpu taking into account the uclamp
+ * settings.
+ *
+ * This check is only important for heterogeneous systems where uclamp_min value
+ * is higher than the capacity of a @cpu. For non-heterogeneous system this
+ * function will always return true.
+ *
+ * The function will return true if the capacity of the @cpu is >= the
+ * uclamp_min and false otherwise.
+ *
+ * Note that uclamp_min will be clamped to uclamp_max if uclamp_min
+ * > uclamp_max.
+ */
+static inline bool rt_task_fits_capacity(struct task_struct *p, int cpu)
+{
+	unsigned int min_cap;
+	unsigned int max_cap;
+	unsigned int cpu_cap;
+
+	/* Only heterogeneous systems can benefit from this check */
+	if (!sched_asym_cpucap_active())
+		return true;
+
+	min_cap = uclamp_eff_value(p, UCLAMP_MIN);
+	max_cap = uclamp_eff_value(p, UCLAMP_MAX);
+
+	cpu_cap = capacity_orig_of(cpu);
+
+	return cpu_cap >= min(min_cap, max_cap);
+}
+#else
+static inline bool rt_task_fits_capacity(struct task_struct *p, int cpu)
+{
+	return true;
+}
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+
+static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
+{
+	if (!rt_rq->tg)
+		return RUNTIME_INF;
+
+	return rt_rq->rt_runtime;
+}
+
+static inline u64 sched_rt_period(struct rt_rq *rt_rq)
+{
+	return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period);
+}
+
+typedef struct task_group *rt_rq_iter_t;
+
+static inline struct task_group *next_task_group(struct task_group *tg)
+{
+	do {
+		tg = list_entry_rcu(tg->list.next,
+			typeof(struct task_group), list);
+	} while (&tg->list != &task_groups && task_group_is_autogroup(tg));
+
+	if (&tg->list == &task_groups)
+		tg = NULL;
+
+	return tg;
+}
+
+#define for_each_rt_rq(rt_rq, iter, rq)					\
+	for (iter = container_of(&task_groups, typeof(*iter), list);	\
+		(iter = next_task_group(iter)) &&			\
+		(rt_rq = iter->rt_rq[cpu_of(rq)]);)
+
+#define for_each_sched_rt_entity(rt_se) \
+	for (; rt_se; rt_se = rt_se->parent)
+
+static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
+{
+	return rt_se->my_q;
+}
+
+static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags);
+static void dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags);
+
+static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
+{
+	struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
+	struct rq *rq = rq_of_rt_rq(rt_rq);
+	struct sched_rt_entity *rt_se;
+
+	int cpu = cpu_of(rq);
+
+	rt_se = rt_rq->tg->rt_se[cpu];
+
+	if (rt_rq->rt_nr_running) {
+		if (!rt_se)
+			enqueue_top_rt_rq(rt_rq);
+		else if (!on_rt_rq(rt_se))
+			enqueue_rt_entity(rt_se, 0);
+
+		if (rt_rq->highest_prio.curr < curr->prio)
+			resched_curr(rq);
+	}
+}
+
+static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
+{
+	struct sched_rt_entity *rt_se;
+	int cpu = cpu_of(rq_of_rt_rq(rt_rq));
+
+	rt_se = rt_rq->tg->rt_se[cpu];
+
+	if (!rt_se) {
+		dequeue_top_rt_rq(rt_rq, rt_rq->rt_nr_running);
+		/* Kick cpufreq (see the comment in kernel/sched/sched.h). */
+		cpufreq_update_util(rq_of_rt_rq(rt_rq), 0);
+	}
+	else if (on_rt_rq(rt_se))
+		dequeue_rt_entity(rt_se, 0);
+}
+
+static inline int rt_rq_throttled(struct rt_rq *rt_rq)
+{
+	return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
+}
+
+static int rt_se_boosted(struct sched_rt_entity *rt_se)
+{
+	struct rt_rq *rt_rq = group_rt_rq(rt_se);
+	struct task_struct *p;
+
+	if (rt_rq)
+		return !!rt_rq->rt_nr_boosted;
+
+	p = rt_task_of(rt_se);
+	return p->prio != p->normal_prio;
+}
+
+#ifdef CONFIG_SMP
+static inline const struct cpumask *sched_rt_period_mask(void)
+{
+	return this_rq()->rd->span;
+}
+#else
+static inline const struct cpumask *sched_rt_period_mask(void)
+{
+	return cpu_online_mask;
+}
+#endif
+
+static inline
+struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
+{
+	return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
+}
+
+static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
+{
+	return &rt_rq->tg->rt_bandwidth;
+}
+
+#else /* !CONFIG_RT_GROUP_SCHED */
+
+static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
+{
+	return rt_rq->rt_runtime;
+}
+
+static inline u64 sched_rt_period(struct rt_rq *rt_rq)
+{
+	return ktime_to_ns(def_rt_bandwidth.rt_period);
+}
+
+typedef struct rt_rq *rt_rq_iter_t;
+
+#define for_each_rt_rq(rt_rq, iter, rq) \
+	for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
+
+#define for_each_sched_rt_entity(rt_se) \
+	for (; rt_se; rt_se = NULL)
+
+static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
+{
+	return NULL;
+}
+
+static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
+{
+	struct rq *rq = rq_of_rt_rq(rt_rq);
+
+	if (!rt_rq->rt_nr_running)
+		return;
+
+	enqueue_top_rt_rq(rt_rq);
+	resched_curr(rq);
+}
+
+static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
+{
+	dequeue_top_rt_rq(rt_rq, rt_rq->rt_nr_running);
+}
+
+static inline int rt_rq_throttled(struct rt_rq *rt_rq)
+{
+	return rt_rq->rt_throttled;
+}
+
+static inline const struct cpumask *sched_rt_period_mask(void)
+{
+	return cpu_online_mask;
+}
+
+static inline
+struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
+{
+	return &cpu_rq(cpu)->rt;
+}
+
+static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
+{
+	return &def_rt_bandwidth;
+}
+
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
+{
+	struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+
+	return (hrtimer_active(&rt_b->rt_period_timer) ||
+		rt_rq->rt_time < rt_b->rt_runtime);
+}
+
+#ifdef CONFIG_SMP
+/*
+ * We ran out of runtime, see if we can borrow some from our neighbours.
+ */
+static void do_balance_runtime(struct rt_rq *rt_rq)
+{
+	struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+	struct root_domain *rd = rq_of_rt_rq(rt_rq)->rd;
+	int i, weight;
+	u64 rt_period;
+
+	weight = cpumask_weight(rd->span);
+
+	raw_spin_lock(&rt_b->rt_runtime_lock);
+	rt_period = ktime_to_ns(rt_b->rt_period);
+	for_each_cpu(i, rd->span) {
+		struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
+		s64 diff;
+
+		if (iter == rt_rq)
+			continue;
+
+		raw_spin_lock(&iter->rt_runtime_lock);
+		/*
+		 * Either all rqs have inf runtime and there's nothing to steal
+		 * or __disable_runtime() below sets a specific rq to inf to
+		 * indicate its been disabled and disallow stealing.
+		 */
+		if (iter->rt_runtime == RUNTIME_INF)
+			goto next;
+
+		/*
+		 * From runqueues with spare time, take 1/n part of their
+		 * spare time, but no more than our period.
+		 */
+		diff = iter->rt_runtime - iter->rt_time;
+		if (diff > 0) {
+			diff = div_u64((u64)diff, weight);
+			if (rt_rq->rt_runtime + diff > rt_period)
+				diff = rt_period - rt_rq->rt_runtime;
+			iter->rt_runtime -= diff;
+			rt_rq->rt_runtime += diff;
+			if (rt_rq->rt_runtime == rt_period) {
+				raw_spin_unlock(&iter->rt_runtime_lock);
+				break;
+			}
+		}
+next:
+		raw_spin_unlock(&iter->rt_runtime_lock);
+	}
+	raw_spin_unlock(&rt_b->rt_runtime_lock);
+}
+
+/*
+ * Ensure this RQ takes back all the runtime it lend to its neighbours.
+ */
+static void __disable_runtime(struct rq *rq)
+{
+	struct root_domain *rd = rq->rd;
+	rt_rq_iter_t iter;
+	struct rt_rq *rt_rq;
+
+	if (unlikely(!scheduler_running))
+		return;
+
+	for_each_rt_rq(rt_rq, iter, rq) {
+		struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+		s64 want;
+		int i;
+
+		raw_spin_lock(&rt_b->rt_runtime_lock);
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		/*
+		 * Either we're all inf and nobody needs to borrow, or we're
+		 * already disabled and thus have nothing to do, or we have
+		 * exactly the right amount of runtime to take out.
+		 */
+		if (rt_rq->rt_runtime == RUNTIME_INF ||
+				rt_rq->rt_runtime == rt_b->rt_runtime)
+			goto balanced;
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+
+		/*
+		 * Calculate the difference between what we started out with
+		 * and what we current have, that's the amount of runtime
+		 * we lend and now have to reclaim.
+		 */
+		want = rt_b->rt_runtime - rt_rq->rt_runtime;
+
+		/*
+		 * Greedy reclaim, take back as much as we can.
+		 */
+		for_each_cpu(i, rd->span) {
+			struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
+			s64 diff;
+
+			/*
+			 * Can't reclaim from ourselves or disabled runqueues.
+			 */
+			if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
+				continue;
+
+			raw_spin_lock(&iter->rt_runtime_lock);
+			if (want > 0) {
+				diff = min_t(s64, iter->rt_runtime, want);
+				iter->rt_runtime -= diff;
+				want -= diff;
+			} else {
+				iter->rt_runtime -= want;
+				want -= want;
+			}
+			raw_spin_unlock(&iter->rt_runtime_lock);
+
+			if (!want)
+				break;
+		}
+
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		/*
+		 * We cannot be left wanting - that would mean some runtime
+		 * leaked out of the system.
+		 */
+		WARN_ON_ONCE(want);
+balanced:
+		/*
+		 * Disable all the borrow logic by pretending we have inf
+		 * runtime - in which case borrowing doesn't make sense.
+		 */
+		rt_rq->rt_runtime = RUNTIME_INF;
+		rt_rq->rt_throttled = 0;
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+		raw_spin_unlock(&rt_b->rt_runtime_lock);
+
+		/* Make rt_rq available for pick_next_task() */
+		sched_rt_rq_enqueue(rt_rq);
+	}
+}
+
+static void __enable_runtime(struct rq *rq)
+{
+	rt_rq_iter_t iter;
+	struct rt_rq *rt_rq;
+
+	if (unlikely(!scheduler_running))
+		return;
+
+	/*
+	 * Reset each runqueue's bandwidth settings
+	 */
+	for_each_rt_rq(rt_rq, iter, rq) {
+		struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+
+		raw_spin_lock(&rt_b->rt_runtime_lock);
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		rt_rq->rt_runtime = rt_b->rt_runtime;
+		rt_rq->rt_time = 0;
+		rt_rq->rt_throttled = 0;
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+		raw_spin_unlock(&rt_b->rt_runtime_lock);
+	}
+}
+
+static void balance_runtime(struct rt_rq *rt_rq)
+{
+	if (!sched_feat(RT_RUNTIME_SHARE))
+		return;
+
+	if (rt_rq->rt_time > rt_rq->rt_runtime) {
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+		do_balance_runtime(rt_rq);
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+	}
+}
+#else /* !CONFIG_SMP */
+static inline void balance_runtime(struct rt_rq *rt_rq) {}
+#endif /* CONFIG_SMP */
+
+static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
+{
+	int i, idle = 1, throttled = 0;
+	const struct cpumask *span;
+
+	span = sched_rt_period_mask();
+#ifdef CONFIG_RT_GROUP_SCHED
+	/*
+	 * FIXME: isolated CPUs should really leave the root task group,
+	 * whether they are isolcpus or were isolated via cpusets, lest
+	 * the timer run on a CPU which does not service all runqueues,
+	 * potentially leaving other CPUs indefinitely throttled.  If
+	 * isolation is really required, the user will turn the throttle
+	 * off to kill the perturbations it causes anyway.  Meanwhile,
+	 * this maintains functionality for boot and/or troubleshooting.
+	 */
+	if (rt_b == &root_task_group.rt_bandwidth)
+		span = cpu_online_mask;
+#endif
+	for_each_cpu(i, span) {
+		int enqueue = 0;
+		struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
+		struct rq *rq = rq_of_rt_rq(rt_rq);
+		struct rq_flags rf;
+		int skip;
+
+		/*
+		 * When span == cpu_online_mask, taking each rq->lock
+		 * can be time-consuming. Try to avoid it when possible.
+		 */
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		if (!sched_feat(RT_RUNTIME_SHARE) && rt_rq->rt_runtime != RUNTIME_INF)
+			rt_rq->rt_runtime = rt_b->rt_runtime;
+		skip = !rt_rq->rt_time && !rt_rq->rt_nr_running;
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+		if (skip)
+			continue;
+
+		rq_lock(rq, &rf);
+		update_rq_clock(rq);
+
+		if (rt_rq->rt_time) {
+			u64 runtime;
+
+			raw_spin_lock(&rt_rq->rt_runtime_lock);
+			if (rt_rq->rt_throttled)
+				balance_runtime(rt_rq);
+			runtime = rt_rq->rt_runtime;
+			rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
+			if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
+				rt_rq->rt_throttled = 0;
+				enqueue = 1;
+
+				/*
+				 * When we're idle and a woken (rt) task is
+				 * throttled check_preempt_curr() will set
+				 * skip_update and the time between the wakeup
+				 * and this unthrottle will get accounted as
+				 * 'runtime'.
+				 */
+				if (rt_rq->rt_nr_running && rq->curr == rq->idle)
+					rq_clock_cancel_skipupdate(rq);
+			}
+			if (rt_rq->rt_time || rt_rq->rt_nr_running)
+				idle = 0;
+			raw_spin_unlock(&rt_rq->rt_runtime_lock);
+		} else if (rt_rq->rt_nr_running) {
+			idle = 0;
+			if (!rt_rq_throttled(rt_rq))
+				enqueue = 1;
+		}
+		if (rt_rq->rt_throttled)
+			throttled = 1;
+
+		if (enqueue)
+			sched_rt_rq_enqueue(rt_rq);
+		rq_unlock(rq, &rf);
+	}
+
+	if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF))
+		return 1;
+
+	return idle;
+}
+
+static inline int rt_se_prio(struct sched_rt_entity *rt_se)
+{
+#ifdef CONFIG_RT_GROUP_SCHED
+	struct rt_rq *rt_rq = group_rt_rq(rt_se);
+
+	if (rt_rq)
+		return rt_rq->highest_prio.curr;
+#endif
+
+	return rt_task_of(rt_se)->prio;
+}
+
+static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
+{
+	u64 runtime = sched_rt_runtime(rt_rq);
+
+	if (rt_rq->rt_throttled)
+		return rt_rq_throttled(rt_rq);
+
+	if (runtime >= sched_rt_period(rt_rq))
+		return 0;
+
+	balance_runtime(rt_rq);
+	runtime = sched_rt_runtime(rt_rq);
+	if (runtime == RUNTIME_INF)
+		return 0;
+
+	if (rt_rq->rt_time > runtime) {
+		struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
+
+		/*
+		 * Don't actually throttle groups that have no runtime assigned
+		 * but accrue some time due to boosting.
+		 */
+		if (likely(rt_b->rt_runtime)) {
+			rt_rq->rt_throttled = 1;
+			printk_deferred_once("sched: RT throttling activated\n");
+		} else {
+			/*
+			 * In case we did anyway, make it go away,
+			 * replenishment is a joke, since it will replenish us
+			 * with exactly 0 ns.
+			 */
+			rt_rq->rt_time = 0;
+		}
+
+		if (rt_rq_throttled(rt_rq)) {
+			sched_rt_rq_dequeue(rt_rq);
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Update the current task's runtime statistics. Skip current tasks that
+ * are not in our scheduling class.
+ */
+static void update_curr_rt(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+	struct sched_rt_entity *rt_se = &curr->rt;
+	u64 delta_exec;
+	u64 now;
+
+	if (curr->sched_class != &rt_sched_class)
+		return;
+
+	now = rq_clock_task(rq);
+	delta_exec = now - curr->se.exec_start;
+	if (unlikely((s64)delta_exec <= 0))
+		return;
+
+	schedstat_set(curr->stats.exec_max,
+		      max(curr->stats.exec_max, delta_exec));
+
+	trace_sched_stat_runtime(curr, delta_exec, 0);
+
+	update_current_exec_runtime(curr, now, delta_exec);
+
+	if (!rt_bandwidth_enabled())
+		return;
+
+	for_each_sched_rt_entity(rt_se) {
+		struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
+		int exceeded;
+
+		if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
+			raw_spin_lock(&rt_rq->rt_runtime_lock);
+			rt_rq->rt_time += delta_exec;
+			exceeded = sched_rt_runtime_exceeded(rt_rq);
+			if (exceeded)
+				resched_curr(rq);
+			raw_spin_unlock(&rt_rq->rt_runtime_lock);
+			if (exceeded)
+				do_start_rt_bandwidth(sched_rt_bandwidth(rt_rq));
+		}
+	}
+}
+
+static void
+dequeue_top_rt_rq(struct rt_rq *rt_rq, unsigned int count)
+{
+	struct rq *rq = rq_of_rt_rq(rt_rq);
+
+	BUG_ON(&rq->rt != rt_rq);
+
+	if (!rt_rq->rt_queued)
+		return;
+
+	BUG_ON(!rq->nr_running);
+
+	sub_nr_running(rq, count);
+	rt_rq->rt_queued = 0;
+
+}
+
+static void
+enqueue_top_rt_rq(struct rt_rq *rt_rq)
+{
+	struct rq *rq = rq_of_rt_rq(rt_rq);
+
+	BUG_ON(&rq->rt != rt_rq);
+
+	if (rt_rq->rt_queued)
+		return;
+
+	if (rt_rq_throttled(rt_rq))
+		return;
+
+	if (rt_rq->rt_nr_running) {
+		add_nr_running(rq, rt_rq->rt_nr_running);
+		rt_rq->rt_queued = 1;
+	}
+
+	/* Kick cpufreq (see the comment in kernel/sched/sched.h). */
+	cpufreq_update_util(rq, 0);
+}
+
+#if defined CONFIG_SMP
+
+static void
+inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
+{
+	struct rq *rq = rq_of_rt_rq(rt_rq);
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	/*
+	 * Change rq's cpupri only if rt_rq is the top queue.
+	 */
+	if (&rq->rt != rt_rq)
+		return;
+#endif
+	if (rq->online && prio < prev_prio)
+		cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
+}
+
+static void
+dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
+{
+	struct rq *rq = rq_of_rt_rq(rt_rq);
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	/*
+	 * Change rq's cpupri only if rt_rq is the top queue.
+	 */
+	if (&rq->rt != rt_rq)
+		return;
+#endif
+	if (rq->online && rt_rq->highest_prio.curr != prev_prio)
+		cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
+}
+
+#else /* CONFIG_SMP */
+
+static inline
+void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
+static inline
+void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
+
+#endif /* CONFIG_SMP */
+
+#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
+static void
+inc_rt_prio(struct rt_rq *rt_rq, int prio)
+{
+	int prev_prio = rt_rq->highest_prio.curr;
+
+	if (prio < prev_prio)
+		rt_rq->highest_prio.curr = prio;
+
+	inc_rt_prio_smp(rt_rq, prio, prev_prio);
+}
+
+static void
+dec_rt_prio(struct rt_rq *rt_rq, int prio)
+{
+	int prev_prio = rt_rq->highest_prio.curr;
+
+	if (rt_rq->rt_nr_running) {
+
+		WARN_ON(prio < prev_prio);
+
+		/*
+		 * This may have been our highest task, and therefore
+		 * we may have some recomputation to do
+		 */
+		if (prio == prev_prio) {
+			struct rt_prio_array *array = &rt_rq->active;
+
+			rt_rq->highest_prio.curr =
+				sched_find_first_bit(array->bitmap);
+		}
+
+	} else {
+		rt_rq->highest_prio.curr = MAX_RT_PRIO-1;
+	}
+
+	dec_rt_prio_smp(rt_rq, prio, prev_prio);
+}
+
+#else
+
+static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {}
+static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {}
+
+#endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_RT_GROUP_SCHED
+
+static void
+inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	if (rt_se_boosted(rt_se))
+		rt_rq->rt_nr_boosted++;
+
+	if (rt_rq->tg)
+		start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
+}
+
+static void
+dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	if (rt_se_boosted(rt_se))
+		rt_rq->rt_nr_boosted--;
+
+	WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
+}
+
+#else /* CONFIG_RT_GROUP_SCHED */
+
+static void
+inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	start_rt_bandwidth(&def_rt_bandwidth);
+}
+
+static inline
+void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {}
+
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+static inline
+unsigned int rt_se_nr_running(struct sched_rt_entity *rt_se)
+{
+	struct rt_rq *group_rq = group_rt_rq(rt_se);
+
+	if (group_rq)
+		return group_rq->rt_nr_running;
+	else
+		return 1;
+}
+
+static inline
+unsigned int rt_se_rr_nr_running(struct sched_rt_entity *rt_se)
+{
+	struct rt_rq *group_rq = group_rt_rq(rt_se);
+	struct task_struct *tsk;
+
+	if (group_rq)
+		return group_rq->rr_nr_running;
+
+	tsk = rt_task_of(rt_se);
+
+	return (tsk->policy == SCHED_RR) ? 1 : 0;
+}
+
+static inline
+void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	int prio = rt_se_prio(rt_se);
+
+	WARN_ON(!rt_prio(prio));
+	rt_rq->rt_nr_running += rt_se_nr_running(rt_se);
+	rt_rq->rr_nr_running += rt_se_rr_nr_running(rt_se);
+
+	inc_rt_prio(rt_rq, prio);
+	inc_rt_migration(rt_se, rt_rq);
+	inc_rt_group(rt_se, rt_rq);
+}
+
+static inline
+void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+{
+	WARN_ON(!rt_prio(rt_se_prio(rt_se)));
+	WARN_ON(!rt_rq->rt_nr_running);
+	rt_rq->rt_nr_running -= rt_se_nr_running(rt_se);
+	rt_rq->rr_nr_running -= rt_se_rr_nr_running(rt_se);
+
+	dec_rt_prio(rt_rq, rt_se_prio(rt_se));
+	dec_rt_migration(rt_se, rt_rq);
+	dec_rt_group(rt_se, rt_rq);
+}
+
+/*
+ * Change rt_se->run_list location unless SAVE && !MOVE
+ *
+ * assumes ENQUEUE/DEQUEUE flags match
+ */
+static inline bool move_entity(unsigned int flags)
+{
+	if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) == DEQUEUE_SAVE)
+		return false;
+
+	return true;
+}
+
+static void __delist_rt_entity(struct sched_rt_entity *rt_se, struct rt_prio_array *array)
+{
+	list_del_init(&rt_se->run_list);
+
+	if (list_empty(array->queue + rt_se_prio(rt_se)))
+		__clear_bit(rt_se_prio(rt_se), array->bitmap);
+
+	rt_se->on_list = 0;
+}
+
+static inline struct sched_statistics *
+__schedstats_from_rt_se(struct sched_rt_entity *rt_se)
+{
+#ifdef CONFIG_RT_GROUP_SCHED
+	/* schedstats is not supported for rt group. */
+	if (!rt_entity_is_task(rt_se))
+		return NULL;
+#endif
+
+	return &rt_task_of(rt_se)->stats;
+}
+
+static inline void
+update_stats_wait_start_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+{
+	struct sched_statistics *stats;
+	struct task_struct *p = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	if (rt_entity_is_task(rt_se))
+		p = rt_task_of(rt_se);
+
+	stats = __schedstats_from_rt_se(rt_se);
+	if (!stats)
+		return;
+
+	__update_stats_wait_start(rq_of_rt_rq(rt_rq), p, stats);
+}
+
+static inline void
+update_stats_enqueue_sleeper_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+{
+	struct sched_statistics *stats;
+	struct task_struct *p = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	if (rt_entity_is_task(rt_se))
+		p = rt_task_of(rt_se);
+
+	stats = __schedstats_from_rt_se(rt_se);
+	if (!stats)
+		return;
+
+	__update_stats_enqueue_sleeper(rq_of_rt_rq(rt_rq), p, stats);
+}
+
+static inline void
+update_stats_enqueue_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
+			int flags)
+{
+	if (!schedstat_enabled())
+		return;
+
+	if (flags & ENQUEUE_WAKEUP)
+		update_stats_enqueue_sleeper_rt(rt_rq, rt_se);
+}
+
+static inline void
+update_stats_wait_end_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+{
+	struct sched_statistics *stats;
+	struct task_struct *p = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	if (rt_entity_is_task(rt_se))
+		p = rt_task_of(rt_se);
+
+	stats = __schedstats_from_rt_se(rt_se);
+	if (!stats)
+		return;
+
+	__update_stats_wait_end(rq_of_rt_rq(rt_rq), p, stats);
+}
+
+static inline void
+update_stats_dequeue_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
+			int flags)
+{
+	struct task_struct *p = NULL;
+
+	if (!schedstat_enabled())
+		return;
+
+	if (rt_entity_is_task(rt_se))
+		p = rt_task_of(rt_se);
+
+	if ((flags & DEQUEUE_SLEEP) && p) {
+		unsigned int state;
+
+		state = READ_ONCE(p->__state);
+		if (state & TASK_INTERRUPTIBLE)
+			__schedstat_set(p->stats.sleep_start,
+					rq_clock(rq_of_rt_rq(rt_rq)));
+
+		if (state & TASK_UNINTERRUPTIBLE)
+			__schedstat_set(p->stats.block_start,
+					rq_clock(rq_of_rt_rq(rt_rq)));
+	}
+}
+
+static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
+{
+	struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
+	struct rt_prio_array *array = &rt_rq->active;
+	struct rt_rq *group_rq = group_rt_rq(rt_se);
+	struct list_head *queue = array->queue + rt_se_prio(rt_se);
+
+	/*
+	 * Don't enqueue the group if its throttled, or when empty.
+	 * The latter is a consequence of the former when a child group
+	 * get throttled and the current group doesn't have any other
+	 * active members.
+	 */
+	if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running)) {
+		if (rt_se->on_list)
+			__delist_rt_entity(rt_se, array);
+		return;
+	}
+
+	if (move_entity(flags)) {
+		WARN_ON_ONCE(rt_se->on_list);
+		if (flags & ENQUEUE_HEAD)
+			list_add(&rt_se->run_list, queue);
+		else
+			list_add_tail(&rt_se->run_list, queue);
+
+		__set_bit(rt_se_prio(rt_se), array->bitmap);
+		rt_se->on_list = 1;
+	}
+	rt_se->on_rq = 1;
+
+	inc_rt_tasks(rt_se, rt_rq);
+}
+
+static void __dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
+{
+	struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
+	struct rt_prio_array *array = &rt_rq->active;
+
+	if (move_entity(flags)) {
+		WARN_ON_ONCE(!rt_se->on_list);
+		__delist_rt_entity(rt_se, array);
+	}
+	rt_se->on_rq = 0;
+
+	dec_rt_tasks(rt_se, rt_rq);
+}
+
+/*
+ * Because the prio of an upper entry depends on the lower
+ * entries, we must remove entries top - down.
+ */
+static void dequeue_rt_stack(struct sched_rt_entity *rt_se, unsigned int flags)
+{
+	struct sched_rt_entity *back = NULL;
+	unsigned int rt_nr_running;
+
+	for_each_sched_rt_entity(rt_se) {
+		rt_se->back = back;
+		back = rt_se;
+	}
+
+	rt_nr_running = rt_rq_of_se(back)->rt_nr_running;
+
+	for (rt_se = back; rt_se; rt_se = rt_se->back) {
+		if (on_rt_rq(rt_se))
+			__dequeue_rt_entity(rt_se, flags);
+	}
+
+	dequeue_top_rt_rq(rt_rq_of_se(back), rt_nr_running);
+}
+
+static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
+{
+	struct rq *rq = rq_of_rt_se(rt_se);
+
+	update_stats_enqueue_rt(rt_rq_of_se(rt_se), rt_se, flags);
+
+	dequeue_rt_stack(rt_se, flags);
+	for_each_sched_rt_entity(rt_se)
+		__enqueue_rt_entity(rt_se, flags);
+	enqueue_top_rt_rq(&rq->rt);
+}
+
+static void dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
+{
+	struct rq *rq = rq_of_rt_se(rt_se);
+
+	update_stats_dequeue_rt(rt_rq_of_se(rt_se), rt_se, flags);
+
+	dequeue_rt_stack(rt_se, flags);
+
+	for_each_sched_rt_entity(rt_se) {
+		struct rt_rq *rt_rq = group_rt_rq(rt_se);
+
+		if (rt_rq && rt_rq->rt_nr_running)
+			__enqueue_rt_entity(rt_se, flags);
+	}
+	enqueue_top_rt_rq(&rq->rt);
+}
+
+/*
+ * Adding/removing a task to/from a priority array:
+ */
+static void
+enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
+{
+	struct sched_rt_entity *rt_se = &p->rt;
+
+	if (flags & ENQUEUE_WAKEUP)
+		rt_se->timeout = 0;
+
+	check_schedstat_required();
+	update_stats_wait_start_rt(rt_rq_of_se(rt_se), rt_se);
+
+	enqueue_rt_entity(rt_se, flags);
+
+	if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
+		enqueue_pushable_task(rq, p);
+}
+
+static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
+{
+	struct sched_rt_entity *rt_se = &p->rt;
+
+	update_curr_rt(rq);
+	dequeue_rt_entity(rt_se, flags);
+
+	dequeue_pushable_task(rq, p);
+}
+
+/*
+ * Put task to the head or the end of the run list without the overhead of
+ * dequeue followed by enqueue.
+ */
+static void
+requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
+{
+	if (on_rt_rq(rt_se)) {
+		struct rt_prio_array *array = &rt_rq->active;
+		struct list_head *queue = array->queue + rt_se_prio(rt_se);
+
+		if (head)
+			list_move(&rt_se->run_list, queue);
+		else
+			list_move_tail(&rt_se->run_list, queue);
+	}
+}
+
+static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
+{
+	struct sched_rt_entity *rt_se = &p->rt;
+	struct rt_rq *rt_rq;
+
+	for_each_sched_rt_entity(rt_se) {
+		rt_rq = rt_rq_of_se(rt_se);
+		requeue_rt_entity(rt_rq, rt_se, head);
+	}
+}
+
+static void yield_task_rt(struct rq *rq)
+{
+	requeue_task_rt(rq, rq->curr, 0);
+}
+
+#ifdef CONFIG_SMP
+static int find_lowest_rq(struct task_struct *task);
+
+static int
+select_task_rq_rt(struct task_struct *p, int cpu, int flags)
+{
+	struct task_struct *curr;
+	struct rq *rq;
+	bool test;
+
+	/* For anything but wake ups, just return the task_cpu */
+	if (!(flags & (WF_TTWU | WF_FORK)))
+		goto out;
+
+	rq = cpu_rq(cpu);
+
+	rcu_read_lock();
+	curr = READ_ONCE(rq->curr); /* unlocked access */
+
+	/*
+	 * If the current task on @p's runqueue is an RT task, then
+	 * try to see if we can wake this RT task up on another
+	 * runqueue. Otherwise simply start this RT task
+	 * on its current runqueue.
+	 *
+	 * We want to avoid overloading runqueues. If the woken
+	 * task is a higher priority, then it will stay on this CPU
+	 * and the lower prio task should be moved to another CPU.
+	 * Even though this will probably make the lower prio task
+	 * lose its cache, we do not want to bounce a higher task
+	 * around just because it gave up its CPU, perhaps for a
+	 * lock?
+	 *
+	 * For equal prio tasks, we just let the scheduler sort it out.
+	 *
+	 * Otherwise, just let it ride on the affined RQ and the
+	 * post-schedule router will push the preempted task away
+	 *
+	 * This test is optimistic, if we get it wrong the load-balancer
+	 * will have to sort it out.
+	 *
+	 * We take into account the capacity of the CPU to ensure it fits the
+	 * requirement of the task - which is only important on heterogeneous
+	 * systems like big.LITTLE.
+	 */
+	test = curr &&
+	       unlikely(rt_task(curr)) &&
+	       (curr->nr_cpus_allowed < 2 || curr->prio <= p->prio);
+
+	if (test || !rt_task_fits_capacity(p, cpu)) {
+		int target = find_lowest_rq(p);
+
+		/*
+		 * Bail out if we were forcing a migration to find a better
+		 * fitting CPU but our search failed.
+		 */
+		if (!test && target != -1 && !rt_task_fits_capacity(p, target))
+			goto out_unlock;
+
+		/*
+		 * Don't bother moving it if the destination CPU is
+		 * not running a lower priority task.
+		 */
+		if (target != -1 &&
+		    p->prio < cpu_rq(target)->rt.highest_prio.curr)
+			cpu = target;
+	}
+
+out_unlock:
+	rcu_read_unlock();
+
+out:
+	return cpu;
+}
+
+static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
+{
+	/*
+	 * Current can't be migrated, useless to reschedule,
+	 * let's hope p can move out.
+	 */
+	if (rq->curr->nr_cpus_allowed == 1 ||
+	    !cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
+		return;
+
+	/*
+	 * p is migratable, so let's not schedule it and
+	 * see if it is pushed or pulled somewhere else.
+	 */
+	if (p->nr_cpus_allowed != 1 &&
+	    cpupri_find(&rq->rd->cpupri, p, NULL))
+		return;
+
+	/*
+	 * There appear to be other CPUs that can accept
+	 * the current task but none can run 'p', so lets reschedule
+	 * to try and push the current task away:
+	 */
+	requeue_task_rt(rq, p, 1);
+	resched_curr(rq);
+}
+
+static int balance_rt(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
+{
+	if (!on_rt_rq(&p->rt) && need_pull_rt_task(rq, p)) {
+		/*
+		 * This is OK, because current is on_cpu, which avoids it being
+		 * picked for load-balance and preemption/IRQs are still
+		 * disabled avoiding further scheduler activity on it and we've
+		 * not yet started the picking loop.
+		 */
+		rq_unpin_lock(rq, rf);
+		pull_rt_task(rq);
+		rq_repin_lock(rq, rf);
+	}
+
+	return sched_stop_runnable(rq) || sched_dl_runnable(rq) || sched_rt_runnable(rq);
+}
+#endif /* CONFIG_SMP */
+
+/*
+ * Preempt the current task with a newly woken task if needed:
+ */
+static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
+{
+	if (p->prio < rq->curr->prio) {
+		resched_curr(rq);
+		return;
+	}
+
+#ifdef CONFIG_SMP
+	/*
+	 * If:
+	 *
+	 * - the newly woken task is of equal priority to the current task
+	 * - the newly woken task is non-migratable while current is migratable
+	 * - current will be preempted on the next reschedule
+	 *
+	 * we should check to see if current can readily move to a different
+	 * cpu.  If so, we will reschedule to allow the push logic to try
+	 * to move current somewhere else, making room for our non-migratable
+	 * task.
+	 */
+	if (p->prio == rq->curr->prio && !test_tsk_need_resched(rq->curr))
+		check_preempt_equal_prio(rq, p);
+#endif
+}
+
+static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool first)
+{
+	struct sched_rt_entity *rt_se = &p->rt;
+	struct rt_rq *rt_rq = &rq->rt;
+
+	p->se.exec_start = rq_clock_task(rq);
+	if (on_rt_rq(&p->rt))
+		update_stats_wait_end_rt(rt_rq, rt_se);
+
+	/* The running task is never eligible for pushing */
+	dequeue_pushable_task(rq, p);
+
+	if (!first)
+		return;
+
+	/*
+	 * If prev task was rt, put_prev_task() has already updated the
+	 * utilization. We only care of the case where we start to schedule a
+	 * rt task
+	 */
+	if (rq->curr->sched_class != &rt_sched_class)
+		update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 0);
+
+	rt_queue_push_tasks(rq);
+}
+
+static struct sched_rt_entity *pick_next_rt_entity(struct rt_rq *rt_rq)
+{
+	struct rt_prio_array *array = &rt_rq->active;
+	struct sched_rt_entity *next = NULL;
+	struct list_head *queue;
+	int idx;
+
+	idx = sched_find_first_bit(array->bitmap);
+	BUG_ON(idx >= MAX_RT_PRIO);
+
+	queue = array->queue + idx;
+	if (SCHED_WARN_ON(list_empty(queue)))
+		return NULL;
+	next = list_entry(queue->next, struct sched_rt_entity, run_list);
+
+	return next;
+}
+
+static struct task_struct *_pick_next_task_rt(struct rq *rq)
+{
+	struct sched_rt_entity *rt_se;
+	struct rt_rq *rt_rq  = &rq->rt;
+
+	do {
+		rt_se = pick_next_rt_entity(rt_rq);
+		if (unlikely(!rt_se))
+			return NULL;
+		rt_rq = group_rt_rq(rt_se);
+	} while (rt_rq);
+
+	return rt_task_of(rt_se);
+}
+
+static struct task_struct *pick_task_rt(struct rq *rq)
+{
+	struct task_struct *p;
+
+	if (!sched_rt_runnable(rq))
+		return NULL;
+
+	p = _pick_next_task_rt(rq);
+
+	return p;
+}
+
+static struct task_struct *pick_next_task_rt(struct rq *rq)
+{
+	struct task_struct *p = pick_task_rt(rq);
+
+	if (p)
+		set_next_task_rt(rq, p, true);
+
+	return p;
+}
+
+static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
+{
+	struct sched_rt_entity *rt_se = &p->rt;
+	struct rt_rq *rt_rq = &rq->rt;
+
+	if (on_rt_rq(&p->rt))
+		update_stats_wait_start_rt(rt_rq, rt_se);
+
+	update_curr_rt(rq);
+
+	update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 1);
+
+	/*
+	 * The previous task needs to be made eligible for pushing
+	 * if it is still active
+	 */
+	if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1)
+		enqueue_pushable_task(rq, p);
+}
+
+#ifdef CONFIG_SMP
+
+/* Only try algorithms three times */
+#define RT_MAX_TRIES 3
+
+static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
+{
+	if (!task_on_cpu(rq, p) &&
+	    cpumask_test_cpu(cpu, &p->cpus_mask))
+		return 1;
+
+	return 0;
+}
+
+/*
+ * Return the highest pushable rq's task, which is suitable to be executed
+ * on the CPU, NULL otherwise
+ */
+static struct task_struct *pick_highest_pushable_task(struct rq *rq, int cpu)
+{
+	struct plist_head *head = &rq->rt.pushable_tasks;
+	struct task_struct *p;
+
+	if (!has_pushable_tasks(rq))
+		return NULL;
+
+	plist_for_each_entry(p, head, pushable_tasks) {
+		if (pick_rt_task(rq, p, cpu))
+			return p;
+	}
+
+	return NULL;
+}
+
+static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
+
+static int find_lowest_rq(struct task_struct *task)
+{
+	struct sched_domain *sd;
+	struct cpumask *lowest_mask = this_cpu_cpumask_var_ptr(local_cpu_mask);
+	int this_cpu = smp_processor_id();
+	int cpu      = task_cpu(task);
+	int ret;
+
+	/* Make sure the mask is initialized first */
+	if (unlikely(!lowest_mask))
+		return -1;
+
+	if (task->nr_cpus_allowed == 1)
+		return -1; /* No other targets possible */
+
+	/*
+	 * If we're on asym system ensure we consider the different capacities
+	 * of the CPUs when searching for the lowest_mask.
+	 */
+	if (sched_asym_cpucap_active()) {
+
+		ret = cpupri_find_fitness(&task_rq(task)->rd->cpupri,
+					  task, lowest_mask,
+					  rt_task_fits_capacity);
+	} else {
+
+		ret = cpupri_find(&task_rq(task)->rd->cpupri,
+				  task, lowest_mask);
+	}
+
+	if (!ret)
+		return -1; /* No targets found */
+
+	/*
+	 * At this point we have built a mask of CPUs representing the
+	 * lowest priority tasks in the system.  Now we want to elect
+	 * the best one based on our affinity and topology.
+	 *
+	 * We prioritize the last CPU that the task executed on since
+	 * it is most likely cache-hot in that location.
+	 */
+	if (cpumask_test_cpu(cpu, lowest_mask))
+		return cpu;
+
+	/*
+	 * Otherwise, we consult the sched_domains span maps to figure
+	 * out which CPU is logically closest to our hot cache data.
+	 */
+	if (!cpumask_test_cpu(this_cpu, lowest_mask))
+		this_cpu = -1; /* Skip this_cpu opt if not among lowest */
+
+	rcu_read_lock();
+	for_each_domain(cpu, sd) {
+		if (sd->flags & SD_WAKE_AFFINE) {
+			int best_cpu;
+
+			/*
+			 * "this_cpu" is cheaper to preempt than a
+			 * remote processor.
+			 */
+			if (this_cpu != -1 &&
+			    cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
+				rcu_read_unlock();
+				return this_cpu;
+			}
+
+			best_cpu = cpumask_any_and_distribute(lowest_mask,
+							      sched_domain_span(sd));
+			if (best_cpu < nr_cpu_ids) {
+				rcu_read_unlock();
+				return best_cpu;
+			}
+		}
+	}
+	rcu_read_unlock();
+
+	/*
+	 * And finally, if there were no matches within the domains
+	 * just give the caller *something* to work with from the compatible
+	 * locations.
+	 */
+	if (this_cpu != -1)
+		return this_cpu;
+
+	cpu = cpumask_any_distribute(lowest_mask);
+	if (cpu < nr_cpu_ids)
+		return cpu;
+
+	return -1;
+}
+
+/* Will lock the rq it finds */
+static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
+{
+	struct rq *lowest_rq = NULL;
+	int tries;
+	int cpu;
+
+	for (tries = 0; tries < RT_MAX_TRIES; tries++) {
+		cpu = find_lowest_rq(task);
+
+		if ((cpu == -1) || (cpu == rq->cpu))
+			break;
+
+		lowest_rq = cpu_rq(cpu);
+
+		if (lowest_rq->rt.highest_prio.curr <= task->prio) {
+			/*
+			 * Target rq has tasks of equal or higher priority,
+			 * retrying does not release any lock and is unlikely
+			 * to yield a different result.
+			 */
+			lowest_rq = NULL;
+			break;
+		}
+
+		/* if the prio of this runqueue changed, try again */
+		if (double_lock_balance(rq, lowest_rq)) {
+			/*
+			 * We had to unlock the run queue. In
+			 * the mean time, task could have
+			 * migrated already or had its affinity changed.
+			 * Also make sure that it wasn't scheduled on its rq.
+			 * It is possible the task was scheduled, set
+			 * "migrate_disabled" and then got preempted, so we must
+			 * check the task migration disable flag here too.
+			 */
+			if (unlikely(task_rq(task) != rq ||
+				     !cpumask_test_cpu(lowest_rq->cpu, &task->cpus_mask) ||
+				     task_on_cpu(rq, task) ||
+				     !rt_task(task) ||
+				     is_migration_disabled(task) ||
+				     !task_on_rq_queued(task))) {
+
+				double_unlock_balance(rq, lowest_rq);
+				lowest_rq = NULL;
+				break;
+			}
+		}
+
+		/* If this rq is still suitable use it. */
+		if (lowest_rq->rt.highest_prio.curr > task->prio)
+			break;
+
+		/* try again */
+		double_unlock_balance(rq, lowest_rq);
+		lowest_rq = NULL;
+	}
+
+	return lowest_rq;
+}
+
+static struct task_struct *pick_next_pushable_task(struct rq *rq)
+{
+	struct task_struct *p;
+
+	if (!has_pushable_tasks(rq))
+		return NULL;
+
+	p = plist_first_entry(&rq->rt.pushable_tasks,
+			      struct task_struct, pushable_tasks);
+
+	BUG_ON(rq->cpu != task_cpu(p));
+	BUG_ON(task_current(rq, p));
+	BUG_ON(p->nr_cpus_allowed <= 1);
+
+	BUG_ON(!task_on_rq_queued(p));
+	BUG_ON(!rt_task(p));
+
+	return p;
+}
+
+/*
+ * If the current CPU has more than one RT task, see if the non
+ * running task can migrate over to a CPU that is running a task
+ * of lesser priority.
+ */
+static int push_rt_task(struct rq *rq, bool pull)
+{
+	struct task_struct *next_task;
+	struct rq *lowest_rq;
+	int ret = 0;
+
+	if (!rq->rt.overloaded)
+		return 0;
+
+	next_task = pick_next_pushable_task(rq);
+	if (!next_task)
+		return 0;
+
+retry:
+	/*
+	 * It's possible that the next_task slipped in of
+	 * higher priority than current. If that's the case
+	 * just reschedule current.
+	 */
+	if (unlikely(next_task->prio < rq->curr->prio)) {
+		resched_curr(rq);
+		return 0;
+	}
+
+	if (is_migration_disabled(next_task)) {
+		struct task_struct *push_task = NULL;
+		int cpu;
+
+		if (!pull || rq->push_busy)
+			return 0;
+
+		/*
+		 * Invoking find_lowest_rq() on anything but an RT task doesn't
+		 * make sense. Per the above priority check, curr has to
+		 * be of higher priority than next_task, so no need to
+		 * reschedule when bailing out.
+		 *
+		 * Note that the stoppers are masqueraded as SCHED_FIFO
+		 * (cf. sched_set_stop_task()), so we can't rely on rt_task().
+		 */
+		if (rq->curr->sched_class != &rt_sched_class)
+			return 0;
+
+		cpu = find_lowest_rq(rq->curr);
+		if (cpu == -1 || cpu == rq->cpu)
+			return 0;
+
+		/*
+		 * Given we found a CPU with lower priority than @next_task,
+		 * therefore it should be running. However we cannot migrate it
+		 * to this other CPU, instead attempt to push the current
+		 * running task on this CPU away.
+		 */
+		push_task = get_push_task(rq);
+		if (push_task) {
+			preempt_disable();
+			raw_spin_rq_unlock(rq);
+			stop_one_cpu_nowait(rq->cpu, push_cpu_stop,
+					    push_task, &rq->push_work);
+			preempt_enable();
+			raw_spin_rq_lock(rq);
+		}
+
+		return 0;
+	}
+
+	if (WARN_ON(next_task == rq->curr))
+		return 0;
+
+	/* We might release rq lock */
+	get_task_struct(next_task);
+
+	/* find_lock_lowest_rq locks the rq if found */
+	lowest_rq = find_lock_lowest_rq(next_task, rq);
+	if (!lowest_rq) {
+		struct task_struct *task;
+		/*
+		 * find_lock_lowest_rq releases rq->lock
+		 * so it is possible that next_task has migrated.
+		 *
+		 * We need to make sure that the task is still on the same
+		 * run-queue and is also still the next task eligible for
+		 * pushing.
+		 */
+		task = pick_next_pushable_task(rq);
+		if (task == next_task) {
+			/*
+			 * The task hasn't migrated, and is still the next
+			 * eligible task, but we failed to find a run-queue
+			 * to push it to.  Do not retry in this case, since
+			 * other CPUs will pull from us when ready.
+			 */
+			goto out;
+		}
+
+		if (!task)
+			/* No more tasks, just exit */
+			goto out;
+
+		/*
+		 * Something has shifted, try again.
+		 */
+		put_task_struct(next_task);
+		next_task = task;
+		goto retry;
+	}
+
+	deactivate_task(rq, next_task, 0);
+	set_task_cpu(next_task, lowest_rq->cpu);
+	activate_task(lowest_rq, next_task, 0);
+	resched_curr(lowest_rq);
+	ret = 1;
+
+	double_unlock_balance(rq, lowest_rq);
+out:
+	put_task_struct(next_task);
+
+	return ret;
+}
+
+static void push_rt_tasks(struct rq *rq)
+{
+	/* push_rt_task will return true if it moved an RT */
+	while (push_rt_task(rq, false))
+		;
+}
+
+#ifdef HAVE_RT_PUSH_IPI
+
+/*
+ * When a high priority task schedules out from a CPU and a lower priority
+ * task is scheduled in, a check is made to see if there's any RT tasks
+ * on other CPUs that are waiting to run because a higher priority RT task
+ * is currently running on its CPU. In this case, the CPU with multiple RT
+ * tasks queued on it (overloaded) needs to be notified that a CPU has opened
+ * up that may be able to run one of its non-running queued RT tasks.
+ *
+ * All CPUs with overloaded RT tasks need to be notified as there is currently
+ * no way to know which of these CPUs have the highest priority task waiting
+ * to run. Instead of trying to take a spinlock on each of these CPUs,
+ * which has shown to cause large latency when done on machines with many
+ * CPUs, sending an IPI to the CPUs to have them push off the overloaded
+ * RT tasks waiting to run.
+ *
+ * Just sending an IPI to each of the CPUs is also an issue, as on large
+ * count CPU machines, this can cause an IPI storm on a CPU, especially
+ * if its the only CPU with multiple RT tasks queued, and a large number
+ * of CPUs scheduling a lower priority task at the same time.
+ *
+ * Each root domain has its own irq work function that can iterate over
+ * all CPUs with RT overloaded tasks. Since all CPUs with overloaded RT
+ * task must be checked if there's one or many CPUs that are lowering
+ * their priority, there's a single irq work iterator that will try to
+ * push off RT tasks that are waiting to run.
+ *
+ * When a CPU schedules a lower priority task, it will kick off the
+ * irq work iterator that will jump to each CPU with overloaded RT tasks.
+ * As it only takes the first CPU that schedules a lower priority task
+ * to start the process, the rto_start variable is incremented and if
+ * the atomic result is one, then that CPU will try to take the rto_lock.
+ * This prevents high contention on the lock as the process handles all
+ * CPUs scheduling lower priority tasks.
+ *
+ * All CPUs that are scheduling a lower priority task will increment the
+ * rt_loop_next variable. This will make sure that the irq work iterator
+ * checks all RT overloaded CPUs whenever a CPU schedules a new lower
+ * priority task, even if the iterator is in the middle of a scan. Incrementing
+ * the rt_loop_next will cause the iterator to perform another scan.
+ *
+ */
+static int rto_next_cpu(struct root_domain *rd)
+{
+	int next;
+	int cpu;
+
+	/*
+	 * When starting the IPI RT pushing, the rto_cpu is set to -1,
+	 * rt_next_cpu() will simply return the first CPU found in
+	 * the rto_mask.
+	 *
+	 * If rto_next_cpu() is called with rto_cpu is a valid CPU, it
+	 * will return the next CPU found in the rto_mask.
+	 *
+	 * If there are no more CPUs left in the rto_mask, then a check is made
+	 * against rto_loop and rto_loop_next. rto_loop is only updated with
+	 * the rto_lock held, but any CPU may increment the rto_loop_next
+	 * without any locking.
+	 */
+	for (;;) {
+
+		/* When rto_cpu is -1 this acts like cpumask_first() */
+		cpu = cpumask_next(rd->rto_cpu, rd->rto_mask);
+
+		rd->rto_cpu = cpu;
+
+		if (cpu < nr_cpu_ids)
+			return cpu;
+
+		rd->rto_cpu = -1;
+
+		/*
+		 * ACQUIRE ensures we see the @rto_mask changes
+		 * made prior to the @next value observed.
+		 *
+		 * Matches WMB in rt_set_overload().
+		 */
+		next = atomic_read_acquire(&rd->rto_loop_next);
+
+		if (rd->rto_loop == next)
+			break;
+
+		rd->rto_loop = next;
+	}
+
+	return -1;
+}
+
+static inline bool rto_start_trylock(atomic_t *v)
+{
+	return !atomic_cmpxchg_acquire(v, 0, 1);
+}
+
+static inline void rto_start_unlock(atomic_t *v)
+{
+	atomic_set_release(v, 0);
+}
+
+static void tell_cpu_to_push(struct rq *rq)
+{
+	int cpu = -1;
+
+	/* Keep the loop going if the IPI is currently active */
+	atomic_inc(&rq->rd->rto_loop_next);
+
+	/* Only one CPU can initiate a loop at a time */
+	if (!rto_start_trylock(&rq->rd->rto_loop_start))
+		return;
+
+	raw_spin_lock(&rq->rd->rto_lock);
+
+	/*
+	 * The rto_cpu is updated under the lock, if it has a valid CPU
+	 * then the IPI is still running and will continue due to the
+	 * update to loop_next, and nothing needs to be done here.
+	 * Otherwise it is finishing up and an ipi needs to be sent.
+	 */
+	if (rq->rd->rto_cpu < 0)
+		cpu = rto_next_cpu(rq->rd);
+
+	raw_spin_unlock(&rq->rd->rto_lock);
+
+	rto_start_unlock(&rq->rd->rto_loop_start);
+
+	if (cpu >= 0) {
+		/* Make sure the rd does not get freed while pushing */
+		sched_get_rd(rq->rd);
+		irq_work_queue_on(&rq->rd->rto_push_work, cpu);
+	}
+}
+
+/* Called from hardirq context */
+void rto_push_irq_work_func(struct irq_work *work)
+{
+	struct root_domain *rd =
+		container_of(work, struct root_domain, rto_push_work);
+	struct rq *rq;
+	int cpu;
+
+	rq = this_rq();
+
+	/*
+	 * We do not need to grab the lock to check for has_pushable_tasks.
+	 * When it gets updated, a check is made if a push is possible.
+	 */
+	if (has_pushable_tasks(rq)) {
+		raw_spin_rq_lock(rq);
+		while (push_rt_task(rq, true))
+			;
+		raw_spin_rq_unlock(rq);
+	}
+
+	raw_spin_lock(&rd->rto_lock);
+
+	/* Pass the IPI to the next rt overloaded queue */
+	cpu = rto_next_cpu(rd);
+
+	raw_spin_unlock(&rd->rto_lock);
+
+	if (cpu < 0) {
+		sched_put_rd(rd);
+		return;
+	}
+
+	/* Try the next RT overloaded CPU */
+	irq_work_queue_on(&rd->rto_push_work, cpu);
+}
+#endif /* HAVE_RT_PUSH_IPI */
+
+static void pull_rt_task(struct rq *this_rq)
+{
+	int this_cpu = this_rq->cpu, cpu;
+	bool resched = false;
+	struct task_struct *p, *push_task;
+	struct rq *src_rq;
+	int rt_overload_count = rt_overloaded(this_rq);
+
+	if (likely(!rt_overload_count))
+		return;
+
+	/*
+	 * Match the barrier from rt_set_overloaded; this guarantees that if we
+	 * see overloaded we must also see the rto_mask bit.
+	 */
+	smp_rmb();
+
+	/* If we are the only overloaded CPU do nothing */
+	if (rt_overload_count == 1 &&
+	    cpumask_test_cpu(this_rq->cpu, this_rq->rd->rto_mask))
+		return;
+
+#ifdef HAVE_RT_PUSH_IPI
+	if (sched_feat(RT_PUSH_IPI)) {
+		tell_cpu_to_push(this_rq);
+		return;
+	}
+#endif
+
+	for_each_cpu(cpu, this_rq->rd->rto_mask) {
+		if (this_cpu == cpu)
+			continue;
+
+		src_rq = cpu_rq(cpu);
+
+		/*
+		 * Don't bother taking the src_rq->lock if the next highest
+		 * task is known to be lower-priority than our current task.
+		 * This may look racy, but if this value is about to go
+		 * logically higher, the src_rq will push this task away.
+		 * And if its going logically lower, we do not care
+		 */
+		if (src_rq->rt.highest_prio.next >=
+		    this_rq->rt.highest_prio.curr)
+			continue;
+
+		/*
+		 * We can potentially drop this_rq's lock in
+		 * double_lock_balance, and another CPU could
+		 * alter this_rq
+		 */
+		push_task = NULL;
+		double_lock_balance(this_rq, src_rq);
+
+		/*
+		 * We can pull only a task, which is pushable
+		 * on its rq, and no others.
+		 */
+		p = pick_highest_pushable_task(src_rq, this_cpu);
+
+		/*
+		 * Do we have an RT task that preempts
+		 * the to-be-scheduled task?
+		 */
+		if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
+			WARN_ON(p == src_rq->curr);
+			WARN_ON(!task_on_rq_queued(p));
+
+			/*
+			 * There's a chance that p is higher in priority
+			 * than what's currently running on its CPU.
+			 * This is just that p is waking up and hasn't
+			 * had a chance to schedule. We only pull
+			 * p if it is lower in priority than the
+			 * current task on the run queue
+			 */
+			if (p->prio < src_rq->curr->prio)
+				goto skip;
+
+			if (is_migration_disabled(p)) {
+				push_task = get_push_task(src_rq);
+			} else {
+				deactivate_task(src_rq, p, 0);
+				set_task_cpu(p, this_cpu);
+				activate_task(this_rq, p, 0);
+				resched = true;
+			}
+			/*
+			 * We continue with the search, just in
+			 * case there's an even higher prio task
+			 * in another runqueue. (low likelihood
+			 * but possible)
+			 */
+		}
+skip:
+		double_unlock_balance(this_rq, src_rq);
+
+		if (push_task) {
+			preempt_disable();
+			raw_spin_rq_unlock(this_rq);
+			stop_one_cpu_nowait(src_rq->cpu, push_cpu_stop,
+					    push_task, &src_rq->push_work);
+			preempt_enable();
+			raw_spin_rq_lock(this_rq);
+		}
+	}
+
+	if (resched)
+		resched_curr(this_rq);
+}
+
+/*
+ * If we are not running and we are not going to reschedule soon, we should
+ * try to push tasks away now
+ */
+static void task_woken_rt(struct rq *rq, struct task_struct *p)
+{
+	bool need_to_push = !task_on_cpu(rq, p) &&
+			    !test_tsk_need_resched(rq->curr) &&
+			    p->nr_cpus_allowed > 1 &&
+			    (dl_task(rq->curr) || rt_task(rq->curr)) &&
+			    (rq->curr->nr_cpus_allowed < 2 ||
+			     rq->curr->prio <= p->prio);
+
+	if (need_to_push)
+		push_rt_tasks(rq);
+}
+
+/* Assumes rq->lock is held */
+static void rq_online_rt(struct rq *rq)
+{
+	if (rq->rt.overloaded)
+		rt_set_overload(rq);
+
+	__enable_runtime(rq);
+
+	cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
+}
+
+/* Assumes rq->lock is held */
+static void rq_offline_rt(struct rq *rq)
+{
+	if (rq->rt.overloaded)
+		rt_clear_overload(rq);
+
+	__disable_runtime(rq);
+
+	cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID);
+}
+
+/*
+ * When switch from the rt queue, we bring ourselves to a position
+ * that we might want to pull RT tasks from other runqueues.
+ */
+static void switched_from_rt(struct rq *rq, struct task_struct *p)
+{
+	/*
+	 * If there are other RT tasks then we will reschedule
+	 * and the scheduling of the other RT tasks will handle
+	 * the balancing. But if we are the last RT task
+	 * we may need to handle the pulling of RT tasks
+	 * now.
+	 */
+	if (!task_on_rq_queued(p) || rq->rt.rt_nr_running)
+		return;
+
+	rt_queue_pull_task(rq);
+}
+
+void __init init_sched_rt_class(void)
+{
+	unsigned int i;
+
+	for_each_possible_cpu(i) {
+		zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
+					GFP_KERNEL, cpu_to_node(i));
+	}
+}
+#endif /* CONFIG_SMP */
+
+/*
+ * When switching a task to RT, we may overload the runqueue
+ * with RT tasks. In this case we try to push them off to
+ * other runqueues.
+ */
+static void switched_to_rt(struct rq *rq, struct task_struct *p)
+{
+	/*
+	 * If we are running, update the avg_rt tracking, as the running time
+	 * will now on be accounted into the latter.
+	 */
+	if (task_current(rq, p)) {
+		update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 0);
+		return;
+	}
+
+	/*
+	 * If we are not running we may need to preempt the current
+	 * running task. If that current running task is also an RT task
+	 * then see if we can move to another run queue.
+	 */
+	if (task_on_rq_queued(p)) {
+#ifdef CONFIG_SMP
+		if (p->nr_cpus_allowed > 1 && rq->rt.overloaded)
+			rt_queue_push_tasks(rq);
+#endif /* CONFIG_SMP */
+		if (p->prio < rq->curr->prio && cpu_online(cpu_of(rq)))
+			resched_curr(rq);
+	}
+}
+
+/*
+ * Priority of the task has changed. This may cause
+ * us to initiate a push or pull.
+ */
+static void
+prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
+{
+	if (!task_on_rq_queued(p))
+		return;
+
+	if (task_current(rq, p)) {
+#ifdef CONFIG_SMP
+		/*
+		 * If our priority decreases while running, we
+		 * may need to pull tasks to this runqueue.
+		 */
+		if (oldprio < p->prio)
+			rt_queue_pull_task(rq);
+
+		/*
+		 * If there's a higher priority task waiting to run
+		 * then reschedule.
+		 */
+		if (p->prio > rq->rt.highest_prio.curr)
+			resched_curr(rq);
+#else
+		/* For UP simply resched on drop of prio */
+		if (oldprio < p->prio)
+			resched_curr(rq);
+#endif /* CONFIG_SMP */
+	} else {
+		/*
+		 * This task is not running, but if it is
+		 * greater than the current running task
+		 * then reschedule.
+		 */
+		if (p->prio < rq->curr->prio)
+			resched_curr(rq);
+	}
+}
+
+#ifdef CONFIG_POSIX_TIMERS
+static void watchdog(struct rq *rq, struct task_struct *p)
+{
+	unsigned long soft, hard;
+
+	/* max may change after cur was read, this will be fixed next tick */
+	soft = task_rlimit(p, RLIMIT_RTTIME);
+	hard = task_rlimit_max(p, RLIMIT_RTTIME);
+
+	if (soft != RLIM_INFINITY) {
+		unsigned long next;
+
+		if (p->rt.watchdog_stamp != jiffies) {
+			p->rt.timeout++;
+			p->rt.watchdog_stamp = jiffies;
+		}
+
+		next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
+		if (p->rt.timeout > next) {
+			posix_cputimers_rt_watchdog(&p->posix_cputimers,
+						    p->se.sum_exec_runtime);
+		}
+	}
+}
+#else
+static inline void watchdog(struct rq *rq, struct task_struct *p) { }
+#endif
+
+/*
+ * scheduler tick hitting a task of our scheduling class.
+ *
+ * NOTE: This function can be called remotely by the tick offload that
+ * goes along full dynticks. Therefore no local assumption can be made
+ * and everything must be accessed through the @rq and @curr passed in
+ * parameters.
+ */
+static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
+{
+	struct sched_rt_entity *rt_se = &p->rt;
+
+	update_curr_rt(rq);
+	update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 1);
+
+	watchdog(rq, p);
+
+	/*
+	 * RR tasks need a special form of timeslice management.
+	 * FIFO tasks have no timeslices.
+	 */
+	if (p->policy != SCHED_RR)
+		return;
+
+	if (--p->rt.time_slice)
+		return;
+
+	p->rt.time_slice = sched_rr_timeslice;
+
+	/*
+	 * Requeue to the end of queue if we (and all of our ancestors) are not
+	 * the only element on the queue
+	 */
+	for_each_sched_rt_entity(rt_se) {
+		if (rt_se->run_list.prev != rt_se->run_list.next) {
+			requeue_task_rt(rq, p, 0);
+			resched_curr(rq);
+			return;
+		}
+	}
+}
+
+static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
+{
+	/*
+	 * Time slice is 0 for SCHED_FIFO tasks
+	 */
+	if (task->policy == SCHED_RR)
+		return sched_rr_timeslice;
+	else
+		return 0;
+}
+
+DEFINE_SCHED_CLASS(rt) = {
+
+	.enqueue_task		= enqueue_task_rt,
+	.dequeue_task		= dequeue_task_rt,
+	.yield_task		= yield_task_rt,
+
+	.check_preempt_curr	= check_preempt_curr_rt,
+
+	.pick_next_task		= pick_next_task_rt,
+	.put_prev_task		= put_prev_task_rt,
+	.set_next_task          = set_next_task_rt,
+
+#ifdef CONFIG_SMP
+	.balance		= balance_rt,
+	.pick_task		= pick_task_rt,
+	.select_task_rq		= select_task_rq_rt,
+	.set_cpus_allowed       = set_cpus_allowed_common,
+	.rq_online              = rq_online_rt,
+	.rq_offline             = rq_offline_rt,
+	.task_woken		= task_woken_rt,
+	.switched_from		= switched_from_rt,
+	.find_lock_rq		= find_lock_lowest_rq,
+#endif
+
+	.task_tick		= task_tick_rt,
+
+	.get_rr_interval	= get_rr_interval_rt,
+
+	.prio_changed		= prio_changed_rt,
+	.switched_to		= switched_to_rt,
+
+	.update_curr		= update_curr_rt,
+
+#ifdef CONFIG_UCLAMP_TASK
+	.uclamp_enabled		= 1,
+#endif
+};
+
+#ifdef CONFIG_RT_GROUP_SCHED
+/*
+ * Ensure that the real time constraints are schedulable.
+ */
+static DEFINE_MUTEX(rt_constraints_mutex);
+
+static inline int tg_has_rt_tasks(struct task_group *tg)
+{
+	struct task_struct *task;
+	struct css_task_iter it;
+	int ret = 0;
+
+	/*
+	 * Autogroups do not have RT tasks; see autogroup_create().
+	 */
+	if (task_group_is_autogroup(tg))
+		return 0;
+
+	css_task_iter_start(&tg->css, 0, &it);
+	while (!ret && (task = css_task_iter_next(&it)))
+		ret |= rt_task(task);
+	css_task_iter_end(&it);
+
+	return ret;
+}
+
+struct rt_schedulable_data {
+	struct task_group *tg;
+	u64 rt_period;
+	u64 rt_runtime;
+};
+
+static int tg_rt_schedulable(struct task_group *tg, void *data)
+{
+	struct rt_schedulable_data *d = data;
+	struct task_group *child;
+	unsigned long total, sum = 0;
+	u64 period, runtime;
+
+	period = ktime_to_ns(tg->rt_bandwidth.rt_period);
+	runtime = tg->rt_bandwidth.rt_runtime;
+
+	if (tg == d->tg) {
+		period = d->rt_period;
+		runtime = d->rt_runtime;
+	}
+
+	/*
+	 * Cannot have more runtime than the period.
+	 */
+	if (runtime > period && runtime != RUNTIME_INF)
+		return -EINVAL;
+
+	/*
+	 * Ensure we don't starve existing RT tasks if runtime turns zero.
+	 */
+	if (rt_bandwidth_enabled() && !runtime &&
+	    tg->rt_bandwidth.rt_runtime && tg_has_rt_tasks(tg))
+		return -EBUSY;
+
+	total = to_ratio(period, runtime);
+
+	/*
+	 * Nobody can have more than the global setting allows.
+	 */
+	if (total > to_ratio(global_rt_period(), global_rt_runtime()))
+		return -EINVAL;
+
+	/*
+	 * The sum of our children's runtime should not exceed our own.
+	 */
+	list_for_each_entry_rcu(child, &tg->children, siblings) {
+		period = ktime_to_ns(child->rt_bandwidth.rt_period);
+		runtime = child->rt_bandwidth.rt_runtime;
+
+		if (child == d->tg) {
+			period = d->rt_period;
+			runtime = d->rt_runtime;
+		}
+
+		sum += to_ratio(period, runtime);
+	}
+
+	if (sum > total)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
+{
+	int ret;
+
+	struct rt_schedulable_data data = {
+		.tg = tg,
+		.rt_period = period,
+		.rt_runtime = runtime,
+	};
+
+	rcu_read_lock();
+	ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data);
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static int tg_set_rt_bandwidth(struct task_group *tg,
+		u64 rt_period, u64 rt_runtime)
+{
+	int i, err = 0;
+
+	/*
+	 * Disallowing the root group RT runtime is BAD, it would disallow the
+	 * kernel creating (and or operating) RT threads.
+	 */
+	if (tg == &root_task_group && rt_runtime == 0)
+		return -EINVAL;
+
+	/* No period doesn't make any sense. */
+	if (rt_period == 0)
+		return -EINVAL;
+
+	/*
+	 * Bound quota to defend quota against overflow during bandwidth shift.
+	 */
+	if (rt_runtime != RUNTIME_INF && rt_runtime > max_rt_runtime)
+		return -EINVAL;
+
+	mutex_lock(&rt_constraints_mutex);
+	err = __rt_schedulable(tg, rt_period, rt_runtime);
+	if (err)
+		goto unlock;
+
+	raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
+	tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
+	tg->rt_bandwidth.rt_runtime = rt_runtime;
+
+	for_each_possible_cpu(i) {
+		struct rt_rq *rt_rq = tg->rt_rq[i];
+
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		rt_rq->rt_runtime = rt_runtime;
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+	}
+	raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
+unlock:
+	mutex_unlock(&rt_constraints_mutex);
+
+	return err;
+}
+
+int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
+{
+	u64 rt_runtime, rt_period;
+
+	rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
+	rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
+	if (rt_runtime_us < 0)
+		rt_runtime = RUNTIME_INF;
+	else if ((u64)rt_runtime_us > U64_MAX / NSEC_PER_USEC)
+		return -EINVAL;
+
+	return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
+}
+
+long sched_group_rt_runtime(struct task_group *tg)
+{
+	u64 rt_runtime_us;
+
+	if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
+		return -1;
+
+	rt_runtime_us = tg->rt_bandwidth.rt_runtime;
+	do_div(rt_runtime_us, NSEC_PER_USEC);
+	return rt_runtime_us;
+}
+
+int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us)
+{
+	u64 rt_runtime, rt_period;
+
+	if (rt_period_us > U64_MAX / NSEC_PER_USEC)
+		return -EINVAL;
+
+	rt_period = rt_period_us * NSEC_PER_USEC;
+	rt_runtime = tg->rt_bandwidth.rt_runtime;
+
+	return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
+}
+
+long sched_group_rt_period(struct task_group *tg)
+{
+	u64 rt_period_us;
+
+	rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
+	do_div(rt_period_us, NSEC_PER_USEC);
+	return rt_period_us;
+}
+
+#ifdef CONFIG_SYSCTL
+static int sched_rt_global_constraints(void)
+{
+	int ret = 0;
+
+	mutex_lock(&rt_constraints_mutex);
+	ret = __rt_schedulable(NULL, 0, 0);
+	mutex_unlock(&rt_constraints_mutex);
+
+	return ret;
+}
+#endif /* CONFIG_SYSCTL */
+
+int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
+{
+	/* Don't accept realtime tasks when there is no way for them to run */
+	if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
+		return 0;
+
+	return 1;
+}
+
+#else /* !CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_SYSCTL
+static int sched_rt_global_constraints(void)
+{
+	unsigned long flags;
+	int i;
+
+	raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
+	for_each_possible_cpu(i) {
+		struct rt_rq *rt_rq = &cpu_rq(i)->rt;
+
+		raw_spin_lock(&rt_rq->rt_runtime_lock);
+		rt_rq->rt_runtime = global_rt_runtime();
+		raw_spin_unlock(&rt_rq->rt_runtime_lock);
+	}
+	raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
+
+	return 0;
+}
+#endif /* CONFIG_SYSCTL */
+#endif /* CONFIG_RT_GROUP_SCHED */
+
+#ifdef CONFIG_SYSCTL
+static int sched_rt_global_validate(void)
+{
+	if (sysctl_sched_rt_period <= 0)
+		return -EINVAL;
+
+	if ((sysctl_sched_rt_runtime != RUNTIME_INF) &&
+		((sysctl_sched_rt_runtime > sysctl_sched_rt_period) ||
+		 ((u64)sysctl_sched_rt_runtime *
+			NSEC_PER_USEC > max_rt_runtime)))
+		return -EINVAL;
+
+	return 0;
+}
+
+static void sched_rt_do_global(void)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
+	def_rt_bandwidth.rt_runtime = global_rt_runtime();
+	def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period());
+	raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
+}
+
+static int sched_rt_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	int old_period, old_runtime;
+	static DEFINE_MUTEX(mutex);
+	int ret;
+
+	mutex_lock(&mutex);
+	old_period = sysctl_sched_rt_period;
+	old_runtime = sysctl_sched_rt_runtime;
+
+	ret = proc_dointvec(table, write, buffer, lenp, ppos);
+
+	if (!ret && write) {
+		ret = sched_rt_global_validate();
+		if (ret)
+			goto undo;
+
+		ret = sched_dl_global_validate();
+		if (ret)
+			goto undo;
+
+		ret = sched_rt_global_constraints();
+		if (ret)
+			goto undo;
+
+		sched_rt_do_global();
+		sched_dl_do_global();
+	}
+	if (0) {
+undo:
+		sysctl_sched_rt_period = old_period;
+		sysctl_sched_rt_runtime = old_runtime;
+	}
+	mutex_unlock(&mutex);
+
+	return ret;
+}
+
+static int sched_rr_handler(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	int ret;
+	static DEFINE_MUTEX(mutex);
+
+	mutex_lock(&mutex);
+	ret = proc_dointvec(table, write, buffer, lenp, ppos);
+	/*
+	 * Make sure that internally we keep jiffies.
+	 * Also, writing zero resets the timeslice to default:
+	 */
+	if (!ret && write) {
+		sched_rr_timeslice =
+			sysctl_sched_rr_timeslice <= 0 ? RR_TIMESLICE :
+			msecs_to_jiffies(sysctl_sched_rr_timeslice);
+	}
+	mutex_unlock(&mutex);
+
+	return ret;
+}
+#endif /* CONFIG_SYSCTL */
+
+#ifdef CONFIG_SCHED_DEBUG
+void print_rt_stats(struct seq_file *m, int cpu)
+{
+	rt_rq_iter_t iter;
+	struct rt_rq *rt_rq;
+
+	rcu_read_lock();
+	for_each_rt_rq(rt_rq, iter, cpu_rq(cpu))
+		print_rt_rq(m, cpu, rt_rq);
+	rcu_read_unlock();
+}
+#endif /* CONFIG_SCHED_DEBUG */
diff --git a/kernel/sched/sched-pelt.h b/kernel/sched/sched-pelt.h
new file mode 100644
index 000000000..c529706be
--- /dev/null
+++ b/kernel/sched/sched-pelt.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Generated by Documentation/scheduler/sched-pelt; do not modify. */
+
+static const u32 runnable_avg_yN_inv[] __maybe_unused = {
+	0xffffffff, 0xfa83b2da, 0xf5257d14, 0xefe4b99a, 0xeac0c6e6, 0xe5b906e6,
+	0xe0ccdeeb, 0xdbfbb796, 0xd744fcc9, 0xd2a81d91, 0xce248c14, 0xc9b9bd85,
+	0xc5672a10, 0xc12c4cc9, 0xbd08a39e, 0xb8fbaf46, 0xb504f333, 0xb123f581,
+	0xad583ee9, 0xa9a15ab4, 0xa5fed6a9, 0xa2704302, 0x9ef5325f, 0x9b8d39b9,
+	0x9837f050, 0x94f4efa8, 0x91c3d373, 0x8ea4398a, 0x8b95c1e3, 0x88980e80,
+	0x85aac367, 0x82cd8698,
+};
+
+#define LOAD_AVG_PERIOD 32
+#define LOAD_AVG_MAX 47742
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
new file mode 100644
index 000000000..b62d53d7c
--- /dev/null
+++ b/kernel/sched/sched.h
@@ -0,0 +1,3231 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Scheduler internal types and methods:
+ */
+#ifndef _KERNEL_SCHED_SCHED_H
+#define _KERNEL_SCHED_SCHED_H
+
+#include <linux/sched/affinity.h>
+#include <linux/sched/autogroup.h>
+#include <linux/sched/cpufreq.h>
+#include <linux/sched/deadline.h>
+#include <linux/sched.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/rseq_api.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/smt.h>
+#include <linux/sched/stat.h>
+#include <linux/sched/sysctl.h>
+#include <linux/sched/task_flags.h>
+#include <linux/sched/task.h>
+#include <linux/sched/topology.h>
+
+#include <linux/atomic.h>
+#include <linux/bitmap.h>
+#include <linux/bug.h>
+#include <linux/capability.h>
+#include <linux/cgroup_api.h>
+#include <linux/cgroup.h>
+#include <linux/context_tracking.h>
+#include <linux/cpufreq.h>
+#include <linux/cpumask_api.h>
+#include <linux/ctype.h>
+#include <linux/file.h>
+#include <linux/fs_api.h>
+#include <linux/hrtimer_api.h>
+#include <linux/interrupt.h>
+#include <linux/irq_work.h>
+#include <linux/jiffies.h>
+#include <linux/kref_api.h>
+#include <linux/kthread.h>
+#include <linux/ktime_api.h>
+#include <linux/lockdep_api.h>
+#include <linux/lockdep.h>
+#include <linux/minmax.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mutex_api.h>
+#include <linux/plist.h>
+#include <linux/poll.h>
+#include <linux/proc_fs.h>
+#include <linux/profile.h>
+#include <linux/psi.h>
+#include <linux/rcupdate.h>
+#include <linux/seq_file.h>
+#include <linux/seqlock.h>
+#include <linux/softirq.h>
+#include <linux/spinlock_api.h>
+#include <linux/static_key.h>
+#include <linux/stop_machine.h>
+#include <linux/syscalls_api.h>
+#include <linux/syscalls.h>
+#include <linux/tick.h>
+#include <linux/topology.h>
+#include <linux/types.h>
+#include <linux/u64_stats_sync_api.h>
+#include <linux/uaccess.h>
+#include <linux/wait_api.h>
+#include <linux/wait_bit.h>
+#include <linux/workqueue_api.h>
+
+#include <trace/events/power.h>
+#include <trace/events/sched.h>
+
+#include "../workqueue_internal.h"
+
+#ifdef CONFIG_CGROUP_SCHED
+#include <linux/cgroup.h>
+#include <linux/psi.h>
+#endif
+
+#ifdef CONFIG_SCHED_DEBUG
+# include <linux/static_key.h>
+#endif
+
+#ifdef CONFIG_PARAVIRT
+# include <asm/paravirt.h>
+# include <asm/paravirt_api_clock.h>
+#endif
+
+#include "cpupri.h"
+#include "cpudeadline.h"
+
+#ifdef CONFIG_SCHED_DEBUG
+# define SCHED_WARN_ON(x)      WARN_ONCE(x, #x)
+#else
+# define SCHED_WARN_ON(x)      ({ (void)(x), 0; })
+#endif
+
+struct rq;
+struct cpuidle_state;
+
+/* task_struct::on_rq states: */
+#define TASK_ON_RQ_QUEUED	1
+#define TASK_ON_RQ_MIGRATING	2
+
+extern __read_mostly int scheduler_running;
+
+extern unsigned long calc_load_update;
+extern atomic_long_t calc_load_tasks;
+
+extern unsigned int sysctl_sched_child_runs_first;
+
+extern void calc_global_load_tick(struct rq *this_rq);
+extern long calc_load_fold_active(struct rq *this_rq, long adjust);
+
+extern void call_trace_sched_update_nr_running(struct rq *rq, int count);
+
+extern unsigned int sysctl_sched_rt_period;
+extern int sysctl_sched_rt_runtime;
+extern int sched_rr_timeslice;
+
+/*
+ * Helpers for converting nanosecond timing to jiffy resolution
+ */
+#define NS_TO_JIFFIES(TIME)	((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
+
+/*
+ * Increase resolution of nice-level calculations for 64-bit architectures.
+ * The extra resolution improves shares distribution and load balancing of
+ * low-weight task groups (eg. nice +19 on an autogroup), deeper taskgroup
+ * hierarchies, especially on larger systems. This is not a user-visible change
+ * and does not change the user-interface for setting shares/weights.
+ *
+ * We increase resolution only if we have enough bits to allow this increased
+ * resolution (i.e. 64-bit). The costs for increasing resolution when 32-bit
+ * are pretty high and the returns do not justify the increased costs.
+ *
+ * Really only required when CONFIG_FAIR_GROUP_SCHED=y is also set, but to
+ * increase coverage and consistency always enable it on 64-bit platforms.
+ */
+#ifdef CONFIG_64BIT
+# define NICE_0_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT + SCHED_FIXEDPOINT_SHIFT)
+# define scale_load(w)		((w) << SCHED_FIXEDPOINT_SHIFT)
+# define scale_load_down(w) \
+({ \
+	unsigned long __w = (w); \
+	if (__w) \
+		__w = max(2UL, __w >> SCHED_FIXEDPOINT_SHIFT); \
+	__w; \
+})
+#else
+# define NICE_0_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT)
+# define scale_load(w)		(w)
+# define scale_load_down(w)	(w)
+#endif
+
+/*
+ * Task weight (visible to users) and its load (invisible to users) have
+ * independent resolution, but they should be well calibrated. We use
+ * scale_load() and scale_load_down(w) to convert between them. The
+ * following must be true:
+ *
+ *  scale_load(sched_prio_to_weight[NICE_TO_PRIO(0)-MAX_RT_PRIO]) == NICE_0_LOAD
+ *
+ */
+#define NICE_0_LOAD		(1L << NICE_0_LOAD_SHIFT)
+
+/*
+ * Single value that decides SCHED_DEADLINE internal math precision.
+ * 10 -> just above 1us
+ * 9  -> just above 0.5us
+ */
+#define DL_SCALE		10
+
+/*
+ * Single value that denotes runtime == period, ie unlimited time.
+ */
+#define RUNTIME_INF		((u64)~0ULL)
+
+static inline int idle_policy(int policy)
+{
+	return policy == SCHED_IDLE;
+}
+static inline int fair_policy(int policy)
+{
+	return policy == SCHED_NORMAL || policy == SCHED_BATCH;
+}
+
+static inline int rt_policy(int policy)
+{
+	return policy == SCHED_FIFO || policy == SCHED_RR;
+}
+
+static inline int dl_policy(int policy)
+{
+	return policy == SCHED_DEADLINE;
+}
+static inline bool valid_policy(int policy)
+{
+	return idle_policy(policy) || fair_policy(policy) ||
+		rt_policy(policy) || dl_policy(policy);
+}
+
+static inline int task_has_idle_policy(struct task_struct *p)
+{
+	return idle_policy(p->policy);
+}
+
+static inline int task_has_rt_policy(struct task_struct *p)
+{
+	return rt_policy(p->policy);
+}
+
+static inline int task_has_dl_policy(struct task_struct *p)
+{
+	return dl_policy(p->policy);
+}
+
+#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT)
+
+static inline void update_avg(u64 *avg, u64 sample)
+{
+	s64 diff = sample - *avg;
+	*avg += diff / 8;
+}
+
+/*
+ * Shifting a value by an exponent greater *or equal* to the size of said value
+ * is UB; cap at size-1.
+ */
+#define shr_bound(val, shift)							\
+	(val >> min_t(typeof(shift), shift, BITS_PER_TYPE(typeof(val)) - 1))
+
+/*
+ * !! For sched_setattr_nocheck() (kernel) only !!
+ *
+ * This is actually gross. :(
+ *
+ * It is used to make schedutil kworker(s) higher priority than SCHED_DEADLINE
+ * tasks, but still be able to sleep. We need this on platforms that cannot
+ * atomically change clock frequency. Remove once fast switching will be
+ * available on such platforms.
+ *
+ * SUGOV stands for SchedUtil GOVernor.
+ */
+#define SCHED_FLAG_SUGOV	0x10000000
+
+#define SCHED_DL_FLAGS (SCHED_FLAG_RECLAIM | SCHED_FLAG_DL_OVERRUN | SCHED_FLAG_SUGOV)
+
+static inline bool dl_entity_is_special(struct sched_dl_entity *dl_se)
+{
+#ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
+	return unlikely(dl_se->flags & SCHED_FLAG_SUGOV);
+#else
+	return false;
+#endif
+}
+
+/*
+ * Tells if entity @a should preempt entity @b.
+ */
+static inline bool
+dl_entity_preempt(struct sched_dl_entity *a, struct sched_dl_entity *b)
+{
+	return dl_entity_is_special(a) ||
+	       dl_time_before(a->deadline, b->deadline);
+}
+
+/*
+ * This is the priority-queue data structure of the RT scheduling class:
+ */
+struct rt_prio_array {
+	DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
+	struct list_head queue[MAX_RT_PRIO];
+};
+
+struct rt_bandwidth {
+	/* nests inside the rq lock: */
+	raw_spinlock_t		rt_runtime_lock;
+	ktime_t			rt_period;
+	u64			rt_runtime;
+	struct hrtimer		rt_period_timer;
+	unsigned int		rt_period_active;
+};
+
+void __dl_clear_params(struct task_struct *p);
+
+struct dl_bandwidth {
+	raw_spinlock_t		dl_runtime_lock;
+	u64			dl_runtime;
+	u64			dl_period;
+};
+
+static inline int dl_bandwidth_enabled(void)
+{
+	return sysctl_sched_rt_runtime >= 0;
+}
+
+/*
+ * To keep the bandwidth of -deadline tasks under control
+ * we need some place where:
+ *  - store the maximum -deadline bandwidth of each cpu;
+ *  - cache the fraction of bandwidth that is currently allocated in
+ *    each root domain;
+ *
+ * This is all done in the data structure below. It is similar to the
+ * one used for RT-throttling (rt_bandwidth), with the main difference
+ * that, since here we are only interested in admission control, we
+ * do not decrease any runtime while the group "executes", neither we
+ * need a timer to replenish it.
+ *
+ * With respect to SMP, bandwidth is given on a per root domain basis,
+ * meaning that:
+ *  - bw (< 100%) is the deadline bandwidth of each CPU;
+ *  - total_bw is the currently allocated bandwidth in each root domain;
+ */
+struct dl_bw {
+	raw_spinlock_t		lock;
+	u64			bw;
+	u64			total_bw;
+};
+
+extern void init_dl_bw(struct dl_bw *dl_b);
+extern int  sched_dl_global_validate(void);
+extern void sched_dl_do_global(void);
+extern int  sched_dl_overflow(struct task_struct *p, int policy, const struct sched_attr *attr);
+extern void __setparam_dl(struct task_struct *p, const struct sched_attr *attr);
+extern void __getparam_dl(struct task_struct *p, struct sched_attr *attr);
+extern bool __checkparam_dl(const struct sched_attr *attr);
+extern bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr);
+extern int  dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
+extern int  dl_bw_check_overflow(int cpu);
+
+#ifdef CONFIG_CGROUP_SCHED
+
+struct cfs_rq;
+struct rt_rq;
+
+extern struct list_head task_groups;
+
+struct cfs_bandwidth {
+#ifdef CONFIG_CFS_BANDWIDTH
+	raw_spinlock_t		lock;
+	ktime_t			period;
+	u64			quota;
+	u64			runtime;
+	u64			burst;
+	u64			runtime_snap;
+	s64			hierarchical_quota;
+
+	u8			idle;
+	u8			period_active;
+	u8			slack_started;
+	struct hrtimer		period_timer;
+	struct hrtimer		slack_timer;
+	struct list_head	throttled_cfs_rq;
+
+	/* Statistics: */
+	int			nr_periods;
+	int			nr_throttled;
+	int			nr_burst;
+	u64			throttled_time;
+	u64			burst_time;
+#endif
+};
+
+/* Task group related information */
+struct task_group {
+	struct cgroup_subsys_state css;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	/* schedulable entities of this group on each CPU */
+	struct sched_entity	**se;
+	/* runqueue "owned" by this group on each CPU */
+	struct cfs_rq		**cfs_rq;
+	unsigned long		shares;
+
+	/* A positive value indicates that this is a SCHED_IDLE group. */
+	int			idle;
+
+#ifdef	CONFIG_SMP
+	/*
+	 * load_avg can be heavily contended at clock tick time, so put
+	 * it in its own cacheline separated from the fields above which
+	 * will also be accessed at each tick.
+	 */
+	atomic_long_t		load_avg ____cacheline_aligned;
+#endif
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	struct sched_rt_entity	**rt_se;
+	struct rt_rq		**rt_rq;
+
+	struct rt_bandwidth	rt_bandwidth;
+#endif
+
+	struct rcu_head		rcu;
+	struct list_head	list;
+
+	struct task_group	*parent;
+	struct list_head	siblings;
+	struct list_head	children;
+
+#ifdef CONFIG_SCHED_AUTOGROUP
+	struct autogroup	*autogroup;
+#endif
+
+	struct cfs_bandwidth	cfs_bandwidth;
+
+#ifdef CONFIG_UCLAMP_TASK_GROUP
+	/* The two decimal precision [%] value requested from user-space */
+	unsigned int		uclamp_pct[UCLAMP_CNT];
+	/* Clamp values requested for a task group */
+	struct uclamp_se	uclamp_req[UCLAMP_CNT];
+	/* Effective clamp values used for a task group */
+	struct uclamp_se	uclamp[UCLAMP_CNT];
+#endif
+
+};
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+#define ROOT_TASK_GROUP_LOAD	NICE_0_LOAD
+
+/*
+ * A weight of 0 or 1 can cause arithmetics problems.
+ * A weight of a cfs_rq is the sum of weights of which entities
+ * are queued on this cfs_rq, so a weight of a entity should not be
+ * too large, so as the shares value of a task group.
+ * (The default weight is 1024 - so there's no practical
+ *  limitation from this.)
+ */
+#define MIN_SHARES		(1UL <<  1)
+#define MAX_SHARES		(1UL << 18)
+#endif
+
+typedef int (*tg_visitor)(struct task_group *, void *);
+
+extern int walk_tg_tree_from(struct task_group *from,
+			     tg_visitor down, tg_visitor up, void *data);
+
+/*
+ * Iterate the full tree, calling @down when first entering a node and @up when
+ * leaving it for the final time.
+ *
+ * Caller must hold rcu_lock or sufficient equivalent.
+ */
+static inline int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
+{
+	return walk_tg_tree_from(&root_task_group, down, up, data);
+}
+
+extern int tg_nop(struct task_group *tg, void *data);
+
+extern void free_fair_sched_group(struct task_group *tg);
+extern int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent);
+extern void online_fair_sched_group(struct task_group *tg);
+extern void unregister_fair_sched_group(struct task_group *tg);
+extern void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
+			struct sched_entity *se, int cpu,
+			struct sched_entity *parent);
+extern void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
+
+extern void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b);
+extern void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
+extern void unthrottle_cfs_rq(struct cfs_rq *cfs_rq);
+
+extern void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
+		struct sched_rt_entity *rt_se, int cpu,
+		struct sched_rt_entity *parent);
+extern int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us);
+extern int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us);
+extern long sched_group_rt_runtime(struct task_group *tg);
+extern long sched_group_rt_period(struct task_group *tg);
+extern int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk);
+
+extern struct task_group *sched_create_group(struct task_group *parent);
+extern void sched_online_group(struct task_group *tg,
+			       struct task_group *parent);
+extern void sched_destroy_group(struct task_group *tg);
+extern void sched_release_group(struct task_group *tg);
+
+extern void sched_move_task(struct task_struct *tsk);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+extern int sched_group_set_shares(struct task_group *tg, unsigned long shares);
+
+extern int sched_group_set_idle(struct task_group *tg, long idle);
+
+#ifdef CONFIG_SMP
+extern void set_task_rq_fair(struct sched_entity *se,
+			     struct cfs_rq *prev, struct cfs_rq *next);
+#else /* !CONFIG_SMP */
+static inline void set_task_rq_fair(struct sched_entity *se,
+			     struct cfs_rq *prev, struct cfs_rq *next) { }
+#endif /* CONFIG_SMP */
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+#else /* CONFIG_CGROUP_SCHED */
+
+struct cfs_bandwidth { };
+
+#endif	/* CONFIG_CGROUP_SCHED */
+
+extern void unregister_rt_sched_group(struct task_group *tg);
+extern void free_rt_sched_group(struct task_group *tg);
+extern int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent);
+
+/*
+ * u64_u32_load/u64_u32_store
+ *
+ * Use a copy of a u64 value to protect against data race. This is only
+ * applicable for 32-bits architectures.
+ */
+#ifdef CONFIG_64BIT
+# define u64_u32_load_copy(var, copy)       var
+# define u64_u32_store_copy(var, copy, val) (var = val)
+#else
+# define u64_u32_load_copy(var, copy)					\
+({									\
+	u64 __val, __val_copy;						\
+	do {								\
+		__val_copy = copy;					\
+		/*							\
+		 * paired with u64_u32_store_copy(), ordering access	\
+		 * to var and copy.					\
+		 */							\
+		smp_rmb();						\
+		__val = var;						\
+	} while (__val != __val_copy);					\
+	__val;								\
+})
+# define u64_u32_store_copy(var, copy, val)				\
+do {									\
+	typeof(val) __val = (val);					\
+	var = __val;							\
+	/*								\
+	 * paired with u64_u32_load_copy(), ordering access to var and	\
+	 * copy.							\
+	 */								\
+	smp_wmb();							\
+	copy = __val;							\
+} while (0)
+#endif
+# define u64_u32_load(var)      u64_u32_load_copy(var, var##_copy)
+# define u64_u32_store(var, val) u64_u32_store_copy(var, var##_copy, val)
+
+/* CFS-related fields in a runqueue */
+struct cfs_rq {
+	struct load_weight	load;
+	unsigned int		nr_running;
+	unsigned int		h_nr_running;      /* SCHED_{NORMAL,BATCH,IDLE} */
+	unsigned int		idle_nr_running;   /* SCHED_IDLE */
+	unsigned int		idle_h_nr_running; /* SCHED_IDLE */
+
+	u64			exec_clock;
+	u64			min_vruntime;
+#ifdef CONFIG_SCHED_CORE
+	unsigned int		forceidle_seq;
+	u64			min_vruntime_fi;
+#endif
+
+#ifndef CONFIG_64BIT
+	u64			min_vruntime_copy;
+#endif
+
+	struct rb_root_cached	tasks_timeline;
+
+	/*
+	 * 'curr' points to currently running entity on this cfs_rq.
+	 * It is set to NULL otherwise (i.e when none are currently running).
+	 */
+	struct sched_entity	*curr;
+	struct sched_entity	*next;
+	struct sched_entity	*last;
+	struct sched_entity	*skip;
+
+#ifdef	CONFIG_SCHED_DEBUG
+	unsigned int		nr_spread_over;
+#endif
+
+#ifdef CONFIG_SMP
+	/*
+	 * CFS load tracking
+	 */
+	struct sched_avg	avg;
+#ifndef CONFIG_64BIT
+	u64			last_update_time_copy;
+#endif
+	struct {
+		raw_spinlock_t	lock ____cacheline_aligned;
+		int		nr;
+		unsigned long	load_avg;
+		unsigned long	util_avg;
+		unsigned long	runnable_avg;
+	} removed;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	unsigned long		tg_load_avg_contrib;
+	long			propagate;
+	long			prop_runnable_sum;
+
+	/*
+	 *   h_load = weight * f(tg)
+	 *
+	 * Where f(tg) is the recursive weight fraction assigned to
+	 * this group.
+	 */
+	unsigned long		h_load;
+	u64			last_h_load_update;
+	struct sched_entity	*h_load_next;
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+#endif /* CONFIG_SMP */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	struct rq		*rq;	/* CPU runqueue to which this cfs_rq is attached */
+
+	/*
+	 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
+	 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
+	 * (like users, containers etc.)
+	 *
+	 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a CPU.
+	 * This list is used during load balance.
+	 */
+	int			on_list;
+	struct list_head	leaf_cfs_rq_list;
+	struct task_group	*tg;	/* group that "owns" this runqueue */
+
+	/* Locally cached copy of our task_group's idle value */
+	int			idle;
+
+#ifdef CONFIG_CFS_BANDWIDTH
+	int			runtime_enabled;
+	s64			runtime_remaining;
+
+	u64			throttled_pelt_idle;
+#ifndef CONFIG_64BIT
+	u64                     throttled_pelt_idle_copy;
+#endif
+	u64			throttled_clock;
+	u64			throttled_clock_pelt;
+	u64			throttled_clock_pelt_time;
+	int			throttled;
+	int			throttle_count;
+	struct list_head	throttled_list;
+#endif /* CONFIG_CFS_BANDWIDTH */
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+};
+
+static inline int rt_bandwidth_enabled(void)
+{
+	return sysctl_sched_rt_runtime >= 0;
+}
+
+/* RT IPI pull logic requires IRQ_WORK */
+#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_SMP)
+# define HAVE_RT_PUSH_IPI
+#endif
+
+/* Real-Time classes' related field in a runqueue: */
+struct rt_rq {
+	struct rt_prio_array	active;
+	unsigned int		rt_nr_running;
+	unsigned int		rr_nr_running;
+#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
+	struct {
+		int		curr; /* highest queued rt task prio */
+#ifdef CONFIG_SMP
+		int		next; /* next highest */
+#endif
+	} highest_prio;
+#endif
+#ifdef CONFIG_SMP
+	unsigned int		rt_nr_migratory;
+	unsigned int		rt_nr_total;
+	int			overloaded;
+	struct plist_head	pushable_tasks;
+
+#endif /* CONFIG_SMP */
+	int			rt_queued;
+
+	int			rt_throttled;
+	u64			rt_time;
+	u64			rt_runtime;
+	/* Nests inside the rq lock: */
+	raw_spinlock_t		rt_runtime_lock;
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	unsigned int		rt_nr_boosted;
+
+	struct rq		*rq;
+	struct task_group	*tg;
+#endif
+};
+
+static inline bool rt_rq_is_runnable(struct rt_rq *rt_rq)
+{
+	return rt_rq->rt_queued && rt_rq->rt_nr_running;
+}
+
+/* Deadline class' related fields in a runqueue */
+struct dl_rq {
+	/* runqueue is an rbtree, ordered by deadline */
+	struct rb_root_cached	root;
+
+	unsigned int		dl_nr_running;
+
+#ifdef CONFIG_SMP
+	/*
+	 * Deadline values of the currently executing and the
+	 * earliest ready task on this rq. Caching these facilitates
+	 * the decision whether or not a ready but not running task
+	 * should migrate somewhere else.
+	 */
+	struct {
+		u64		curr;
+		u64		next;
+	} earliest_dl;
+
+	unsigned int		dl_nr_migratory;
+	int			overloaded;
+
+	/*
+	 * Tasks on this rq that can be pushed away. They are kept in
+	 * an rb-tree, ordered by tasks' deadlines, with caching
+	 * of the leftmost (earliest deadline) element.
+	 */
+	struct rb_root_cached	pushable_dl_tasks_root;
+#else
+	struct dl_bw		dl_bw;
+#endif
+	/*
+	 * "Active utilization" for this runqueue: increased when a
+	 * task wakes up (becomes TASK_RUNNING) and decreased when a
+	 * task blocks
+	 */
+	u64			running_bw;
+
+	/*
+	 * Utilization of the tasks "assigned" to this runqueue (including
+	 * the tasks that are in runqueue and the tasks that executed on this
+	 * CPU and blocked). Increased when a task moves to this runqueue, and
+	 * decreased when the task moves away (migrates, changes scheduling
+	 * policy, or terminates).
+	 * This is needed to compute the "inactive utilization" for the
+	 * runqueue (inactive utilization = this_bw - running_bw).
+	 */
+	u64			this_bw;
+	u64			extra_bw;
+
+	/*
+	 * Inverse of the fraction of CPU utilization that can be reclaimed
+	 * by the GRUB algorithm.
+	 */
+	u64			bw_ratio;
+};
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/* An entity is a task if it doesn't "own" a runqueue */
+#define entity_is_task(se)	(!se->my_q)
+
+static inline void se_update_runnable(struct sched_entity *se)
+{
+	if (!entity_is_task(se))
+		se->runnable_weight = se->my_q->h_nr_running;
+}
+
+static inline long se_runnable(struct sched_entity *se)
+{
+	if (entity_is_task(se))
+		return !!se->on_rq;
+	else
+		return se->runnable_weight;
+}
+
+#else
+#define entity_is_task(se)	1
+
+static inline void se_update_runnable(struct sched_entity *se) {}
+
+static inline long se_runnable(struct sched_entity *se)
+{
+	return !!se->on_rq;
+}
+#endif
+
+#ifdef CONFIG_SMP
+/*
+ * XXX we want to get rid of these helpers and use the full load resolution.
+ */
+static inline long se_weight(struct sched_entity *se)
+{
+	return scale_load_down(se->load.weight);
+}
+
+
+static inline bool sched_asym_prefer(int a, int b)
+{
+	return arch_asym_cpu_priority(a) > arch_asym_cpu_priority(b);
+}
+
+struct perf_domain {
+	struct em_perf_domain *em_pd;
+	struct perf_domain *next;
+	struct rcu_head rcu;
+};
+
+/* Scheduling group status flags */
+#define SG_OVERLOAD		0x1 /* More than one runnable task on a CPU. */
+#define SG_OVERUTILIZED		0x2 /* One or more CPUs are over-utilized. */
+
+/*
+ * We add the notion of a root-domain which will be used to define per-domain
+ * variables. Each exclusive cpuset essentially defines an island domain by
+ * fully partitioning the member CPUs from any other cpuset. Whenever a new
+ * exclusive cpuset is created, we also create and attach a new root-domain
+ * object.
+ *
+ */
+struct root_domain {
+	atomic_t		refcount;
+	atomic_t		rto_count;
+	struct rcu_head		rcu;
+	cpumask_var_t		span;
+	cpumask_var_t		online;
+
+	/*
+	 * Indicate pullable load on at least one CPU, e.g:
+	 * - More than one runnable task
+	 * - Running task is misfit
+	 */
+	int			overload;
+
+	/* Indicate one or more cpus over-utilized (tipping point) */
+	int			overutilized;
+
+	/*
+	 * The bit corresponding to a CPU gets set here if such CPU has more
+	 * than one runnable -deadline task (as it is below for RT tasks).
+	 */
+	cpumask_var_t		dlo_mask;
+	atomic_t		dlo_count;
+	struct dl_bw		dl_bw;
+	struct cpudl		cpudl;
+
+	/*
+	 * Indicate whether a root_domain's dl_bw has been checked or
+	 * updated. It's monotonously increasing value.
+	 *
+	 * Also, some corner cases, like 'wrap around' is dangerous, but given
+	 * that u64 is 'big enough'. So that shouldn't be a concern.
+	 */
+	u64 visit_gen;
+
+#ifdef HAVE_RT_PUSH_IPI
+	/*
+	 * For IPI pull requests, loop across the rto_mask.
+	 */
+	struct irq_work		rto_push_work;
+	raw_spinlock_t		rto_lock;
+	/* These are only updated and read within rto_lock */
+	int			rto_loop;
+	int			rto_cpu;
+	/* These atomics are updated outside of a lock */
+	atomic_t		rto_loop_next;
+	atomic_t		rto_loop_start;
+#endif
+	/*
+	 * The "RT overload" flag: it gets set if a CPU has more than
+	 * one runnable RT task.
+	 */
+	cpumask_var_t		rto_mask;
+	struct cpupri		cpupri;
+
+	unsigned long		max_cpu_capacity;
+
+	/*
+	 * NULL-terminated list of performance domains intersecting with the
+	 * CPUs of the rd. Protected by RCU.
+	 */
+	struct perf_domain __rcu *pd;
+};
+
+extern void init_defrootdomain(void);
+extern int sched_init_domains(const struct cpumask *cpu_map);
+extern void rq_attach_root(struct rq *rq, struct root_domain *rd);
+extern void sched_get_rd(struct root_domain *rd);
+extern void sched_put_rd(struct root_domain *rd);
+
+#ifdef HAVE_RT_PUSH_IPI
+extern void rto_push_irq_work_func(struct irq_work *work);
+#endif
+#endif /* CONFIG_SMP */
+
+#ifdef CONFIG_UCLAMP_TASK
+/*
+ * struct uclamp_bucket - Utilization clamp bucket
+ * @value: utilization clamp value for tasks on this clamp bucket
+ * @tasks: number of RUNNABLE tasks on this clamp bucket
+ *
+ * Keep track of how many tasks are RUNNABLE for a given utilization
+ * clamp value.
+ */
+struct uclamp_bucket {
+	unsigned long value : bits_per(SCHED_CAPACITY_SCALE);
+	unsigned long tasks : BITS_PER_LONG - bits_per(SCHED_CAPACITY_SCALE);
+};
+
+/*
+ * struct uclamp_rq - rq's utilization clamp
+ * @value: currently active clamp values for a rq
+ * @bucket: utilization clamp buckets affecting a rq
+ *
+ * Keep track of RUNNABLE tasks on a rq to aggregate their clamp values.
+ * A clamp value is affecting a rq when there is at least one task RUNNABLE
+ * (or actually running) with that value.
+ *
+ * There are up to UCLAMP_CNT possible different clamp values, currently there
+ * are only two: minimum utilization and maximum utilization.
+ *
+ * All utilization clamping values are MAX aggregated, since:
+ * - for util_min: we want to run the CPU at least at the max of the minimum
+ *   utilization required by its currently RUNNABLE tasks.
+ * - for util_max: we want to allow the CPU to run up to the max of the
+ *   maximum utilization allowed by its currently RUNNABLE tasks.
+ *
+ * Since on each system we expect only a limited number of different
+ * utilization clamp values (UCLAMP_BUCKETS), use a simple array to track
+ * the metrics required to compute all the per-rq utilization clamp values.
+ */
+struct uclamp_rq {
+	unsigned int value;
+	struct uclamp_bucket bucket[UCLAMP_BUCKETS];
+};
+
+DECLARE_STATIC_KEY_FALSE(sched_uclamp_used);
+#endif /* CONFIG_UCLAMP_TASK */
+
+struct rq;
+struct balance_callback {
+	struct balance_callback *next;
+	void (*func)(struct rq *rq);
+};
+
+/*
+ * This is the main, per-CPU runqueue data structure.
+ *
+ * Locking rule: those places that want to lock multiple runqueues
+ * (such as the load balancing or the thread migration code), lock
+ * acquire operations must be ordered by ascending &runqueue.
+ */
+struct rq {
+	/* runqueue lock: */
+	raw_spinlock_t		__lock;
+
+	/*
+	 * nr_running and cpu_load should be in the same cacheline because
+	 * remote CPUs use both these fields when doing load calculation.
+	 */
+	unsigned int		nr_running;
+#ifdef CONFIG_NUMA_BALANCING
+	unsigned int		nr_numa_running;
+	unsigned int		nr_preferred_running;
+	unsigned int		numa_migrate_on;
+#endif
+#ifdef CONFIG_NO_HZ_COMMON
+#ifdef CONFIG_SMP
+	unsigned long		last_blocked_load_update_tick;
+	unsigned int		has_blocked_load;
+	call_single_data_t	nohz_csd;
+#endif /* CONFIG_SMP */
+	unsigned int		nohz_tick_stopped;
+	atomic_t		nohz_flags;
+#endif /* CONFIG_NO_HZ_COMMON */
+
+#ifdef CONFIG_SMP
+	unsigned int		ttwu_pending;
+#endif
+	u64			nr_switches;
+
+#ifdef CONFIG_UCLAMP_TASK
+	/* Utilization clamp values based on CPU's RUNNABLE tasks */
+	struct uclamp_rq	uclamp[UCLAMP_CNT] ____cacheline_aligned;
+	unsigned int		uclamp_flags;
+#define UCLAMP_FLAG_IDLE 0x01
+#endif
+
+	struct cfs_rq		cfs;
+	struct rt_rq		rt;
+	struct dl_rq		dl;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	/* list of leaf cfs_rq on this CPU: */
+	struct list_head	leaf_cfs_rq_list;
+	struct list_head	*tmp_alone_branch;
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+
+	/*
+	 * This is part of a global counter where only the total sum
+	 * over all CPUs matters. A task can increase this counter on
+	 * one CPU and if it got migrated afterwards it may decrease
+	 * it on another CPU. Always updated under the runqueue lock:
+	 */
+	unsigned int		nr_uninterruptible;
+
+	struct task_struct __rcu	*curr;
+	struct task_struct	*idle;
+	struct task_struct	*stop;
+	unsigned long		next_balance;
+	struct mm_struct	*prev_mm;
+
+	unsigned int		clock_update_flags;
+	u64			clock;
+	/* Ensure that all clocks are in the same cache line */
+	u64			clock_task ____cacheline_aligned;
+	u64			clock_pelt;
+	unsigned long		lost_idle_time;
+	u64			clock_pelt_idle;
+	u64			clock_idle;
+#ifndef CONFIG_64BIT
+	u64			clock_pelt_idle_copy;
+	u64			clock_idle_copy;
+#endif
+
+	atomic_t		nr_iowait;
+
+#ifdef CONFIG_SCHED_DEBUG
+	u64 last_seen_need_resched_ns;
+	int ticks_without_resched;
+#endif
+
+#ifdef CONFIG_MEMBARRIER
+	int membarrier_state;
+#endif
+
+#ifdef CONFIG_SMP
+	struct root_domain		*rd;
+	struct sched_domain __rcu	*sd;
+
+	unsigned long		cpu_capacity;
+	unsigned long		cpu_capacity_orig;
+
+	struct balance_callback *balance_callback;
+
+	unsigned char		nohz_idle_balance;
+	unsigned char		idle_balance;
+
+	unsigned long		misfit_task_load;
+
+	/* For active balancing */
+	int			active_balance;
+	int			push_cpu;
+	struct cpu_stop_work	active_balance_work;
+
+	/* CPU of this runqueue: */
+	int			cpu;
+	int			online;
+
+	struct list_head cfs_tasks;
+
+	struct sched_avg	avg_rt;
+	struct sched_avg	avg_dl;
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+	struct sched_avg	avg_irq;
+#endif
+#ifdef CONFIG_SCHED_THERMAL_PRESSURE
+	struct sched_avg	avg_thermal;
+#endif
+	u64			idle_stamp;
+	u64			avg_idle;
+
+	unsigned long		wake_stamp;
+	u64			wake_avg_idle;
+
+	/* This is used to determine avg_idle's max value */
+	u64			max_idle_balance_cost;
+
+#ifdef CONFIG_HOTPLUG_CPU
+	struct rcuwait		hotplug_wait;
+#endif
+#endif /* CONFIG_SMP */
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	u64			prev_irq_time;
+#endif
+#ifdef CONFIG_PARAVIRT
+	u64			prev_steal_time;
+#endif
+#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
+	u64			prev_steal_time_rq;
+#endif
+
+	/* calc_load related fields */
+	unsigned long		calc_load_update;
+	long			calc_load_active;
+
+#ifdef CONFIG_SCHED_HRTICK
+#ifdef CONFIG_SMP
+	call_single_data_t	hrtick_csd;
+#endif
+	struct hrtimer		hrtick_timer;
+	ktime_t 		hrtick_time;
+#endif
+
+#ifdef CONFIG_SCHEDSTATS
+	/* latency stats */
+	struct sched_info	rq_sched_info;
+	unsigned long long	rq_cpu_time;
+	/* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
+
+	/* sys_sched_yield() stats */
+	unsigned int		yld_count;
+
+	/* schedule() stats */
+	unsigned int		sched_count;
+	unsigned int		sched_goidle;
+
+	/* try_to_wake_up() stats */
+	unsigned int		ttwu_count;
+	unsigned int		ttwu_local;
+#endif
+
+#ifdef CONFIG_CPU_IDLE
+	/* Must be inspected within a rcu lock section */
+	struct cpuidle_state	*idle_state;
+#endif
+
+#ifdef CONFIG_SMP
+	unsigned int		nr_pinned;
+#endif
+	unsigned int		push_busy;
+	struct cpu_stop_work	push_work;
+
+#ifdef CONFIG_SCHED_CORE
+	/* per rq */
+	struct rq		*core;
+	struct task_struct	*core_pick;
+	unsigned int		core_enabled;
+	unsigned int		core_sched_seq;
+	struct rb_root		core_tree;
+
+	/* shared state -- careful with sched_core_cpu_deactivate() */
+	unsigned int		core_task_seq;
+	unsigned int		core_pick_seq;
+	unsigned long		core_cookie;
+	unsigned int		core_forceidle_count;
+	unsigned int		core_forceidle_seq;
+	unsigned int		core_forceidle_occupation;
+	u64			core_forceidle_start;
+#endif
+};
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+
+/* CPU runqueue to which this cfs_rq is attached */
+static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
+{
+	return cfs_rq->rq;
+}
+
+#else
+
+static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
+{
+	return container_of(cfs_rq, struct rq, cfs);
+}
+#endif
+
+static inline int cpu_of(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+	return rq->cpu;
+#else
+	return 0;
+#endif
+}
+
+#define MDF_PUSH	0x01
+
+static inline bool is_migration_disabled(struct task_struct *p)
+{
+#ifdef CONFIG_SMP
+	return p->migration_disabled;
+#else
+	return false;
+#endif
+}
+
+DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
+
+#define cpu_rq(cpu)		(&per_cpu(runqueues, (cpu)))
+#define this_rq()		this_cpu_ptr(&runqueues)
+#define task_rq(p)		cpu_rq(task_cpu(p))
+#define cpu_curr(cpu)		(cpu_rq(cpu)->curr)
+#define raw_rq()		raw_cpu_ptr(&runqueues)
+
+struct sched_group;
+#ifdef CONFIG_SCHED_CORE
+static inline struct cpumask *sched_group_span(struct sched_group *sg);
+
+DECLARE_STATIC_KEY_FALSE(__sched_core_enabled);
+
+static inline bool sched_core_enabled(struct rq *rq)
+{
+	return static_branch_unlikely(&__sched_core_enabled) && rq->core_enabled;
+}
+
+static inline bool sched_core_disabled(void)
+{
+	return !static_branch_unlikely(&__sched_core_enabled);
+}
+
+/*
+ * Be careful with this function; not for general use. The return value isn't
+ * stable unless you actually hold a relevant rq->__lock.
+ */
+static inline raw_spinlock_t *rq_lockp(struct rq *rq)
+{
+	if (sched_core_enabled(rq))
+		return &rq->core->__lock;
+
+	return &rq->__lock;
+}
+
+static inline raw_spinlock_t *__rq_lockp(struct rq *rq)
+{
+	if (rq->core_enabled)
+		return &rq->core->__lock;
+
+	return &rq->__lock;
+}
+
+bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool fi);
+
+/*
+ * Helpers to check if the CPU's core cookie matches with the task's cookie
+ * when core scheduling is enabled.
+ * A special case is that the task's cookie always matches with CPU's core
+ * cookie if the CPU is in an idle core.
+ */
+static inline bool sched_cpu_cookie_match(struct rq *rq, struct task_struct *p)
+{
+	/* Ignore cookie match if core scheduler is not enabled on the CPU. */
+	if (!sched_core_enabled(rq))
+		return true;
+
+	return rq->core->core_cookie == p->core_cookie;
+}
+
+static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p)
+{
+	bool idle_core = true;
+	int cpu;
+
+	/* Ignore cookie match if core scheduler is not enabled on the CPU. */
+	if (!sched_core_enabled(rq))
+		return true;
+
+	for_each_cpu(cpu, cpu_smt_mask(cpu_of(rq))) {
+		if (!available_idle_cpu(cpu)) {
+			idle_core = false;
+			break;
+		}
+	}
+
+	/*
+	 * A CPU in an idle core is always the best choice for tasks with
+	 * cookies.
+	 */
+	return idle_core || rq->core->core_cookie == p->core_cookie;
+}
+
+static inline bool sched_group_cookie_match(struct rq *rq,
+					    struct task_struct *p,
+					    struct sched_group *group)
+{
+	int cpu;
+
+	/* Ignore cookie match if core scheduler is not enabled on the CPU. */
+	if (!sched_core_enabled(rq))
+		return true;
+
+	for_each_cpu_and(cpu, sched_group_span(group), p->cpus_ptr) {
+		if (sched_core_cookie_match(cpu_rq(cpu), p))
+			return true;
+	}
+	return false;
+}
+
+static inline bool sched_core_enqueued(struct task_struct *p)
+{
+	return !RB_EMPTY_NODE(&p->core_node);
+}
+
+extern void sched_core_enqueue(struct rq *rq, struct task_struct *p);
+extern void sched_core_dequeue(struct rq *rq, struct task_struct *p, int flags);
+
+extern void sched_core_get(void);
+extern void sched_core_put(void);
+
+#else /* !CONFIG_SCHED_CORE */
+
+static inline bool sched_core_enabled(struct rq *rq)
+{
+	return false;
+}
+
+static inline bool sched_core_disabled(void)
+{
+	return true;
+}
+
+static inline raw_spinlock_t *rq_lockp(struct rq *rq)
+{
+	return &rq->__lock;
+}
+
+static inline raw_spinlock_t *__rq_lockp(struct rq *rq)
+{
+	return &rq->__lock;
+}
+
+static inline bool sched_cpu_cookie_match(struct rq *rq, struct task_struct *p)
+{
+	return true;
+}
+
+static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p)
+{
+	return true;
+}
+
+static inline bool sched_group_cookie_match(struct rq *rq,
+					    struct task_struct *p,
+					    struct sched_group *group)
+{
+	return true;
+}
+#endif /* CONFIG_SCHED_CORE */
+
+static inline void lockdep_assert_rq_held(struct rq *rq)
+{
+	lockdep_assert_held(__rq_lockp(rq));
+}
+
+extern void raw_spin_rq_lock_nested(struct rq *rq, int subclass);
+extern bool raw_spin_rq_trylock(struct rq *rq);
+extern void raw_spin_rq_unlock(struct rq *rq);
+
+static inline void raw_spin_rq_lock(struct rq *rq)
+{
+	raw_spin_rq_lock_nested(rq, 0);
+}
+
+static inline void raw_spin_rq_lock_irq(struct rq *rq)
+{
+	local_irq_disable();
+	raw_spin_rq_lock(rq);
+}
+
+static inline void raw_spin_rq_unlock_irq(struct rq *rq)
+{
+	raw_spin_rq_unlock(rq);
+	local_irq_enable();
+}
+
+static inline unsigned long _raw_spin_rq_lock_irqsave(struct rq *rq)
+{
+	unsigned long flags;
+	local_irq_save(flags);
+	raw_spin_rq_lock(rq);
+	return flags;
+}
+
+static inline void raw_spin_rq_unlock_irqrestore(struct rq *rq, unsigned long flags)
+{
+	raw_spin_rq_unlock(rq);
+	local_irq_restore(flags);
+}
+
+#define raw_spin_rq_lock_irqsave(rq, flags)	\
+do {						\
+	flags = _raw_spin_rq_lock_irqsave(rq);	\
+} while (0)
+
+#ifdef CONFIG_SCHED_SMT
+extern void __update_idle_core(struct rq *rq);
+
+static inline void update_idle_core(struct rq *rq)
+{
+	if (static_branch_unlikely(&sched_smt_present))
+		__update_idle_core(rq);
+}
+
+#else
+static inline void update_idle_core(struct rq *rq) { }
+#endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static inline struct task_struct *task_of(struct sched_entity *se)
+{
+	SCHED_WARN_ON(!entity_is_task(se));
+	return container_of(se, struct task_struct, se);
+}
+
+static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
+{
+	return p->se.cfs_rq;
+}
+
+/* runqueue on which this entity is (to be) queued */
+static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
+{
+	return se->cfs_rq;
+}
+
+/* runqueue "owned" by this group */
+static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
+{
+	return grp->my_q;
+}
+
+#else
+
+static inline struct task_struct *task_of(struct sched_entity *se)
+{
+	return container_of(se, struct task_struct, se);
+}
+
+static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
+{
+	return &task_rq(p)->cfs;
+}
+
+static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
+{
+	struct task_struct *p = task_of(se);
+	struct rq *rq = task_rq(p);
+
+	return &rq->cfs;
+}
+
+/* runqueue "owned" by this group */
+static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
+{
+	return NULL;
+}
+#endif
+
+extern void update_rq_clock(struct rq *rq);
+
+/*
+ * rq::clock_update_flags bits
+ *
+ * %RQCF_REQ_SKIP - will request skipping of clock update on the next
+ *  call to __schedule(). This is an optimisation to avoid
+ *  neighbouring rq clock updates.
+ *
+ * %RQCF_ACT_SKIP - is set from inside of __schedule() when skipping is
+ *  in effect and calls to update_rq_clock() are being ignored.
+ *
+ * %RQCF_UPDATED - is a debug flag that indicates whether a call has been
+ *  made to update_rq_clock() since the last time rq::lock was pinned.
+ *
+ * If inside of __schedule(), clock_update_flags will have been
+ * shifted left (a left shift is a cheap operation for the fast path
+ * to promote %RQCF_REQ_SKIP to %RQCF_ACT_SKIP), so you must use,
+ *
+ *	if (rq-clock_update_flags >= RQCF_UPDATED)
+ *
+ * to check if %RQCF_UPDATED is set. It'll never be shifted more than
+ * one position though, because the next rq_unpin_lock() will shift it
+ * back.
+ */
+#define RQCF_REQ_SKIP		0x01
+#define RQCF_ACT_SKIP		0x02
+#define RQCF_UPDATED		0x04
+
+static inline void assert_clock_updated(struct rq *rq)
+{
+	/*
+	 * The only reason for not seeing a clock update since the
+	 * last rq_pin_lock() is if we're currently skipping updates.
+	 */
+	SCHED_WARN_ON(rq->clock_update_flags < RQCF_ACT_SKIP);
+}
+
+static inline u64 rq_clock(struct rq *rq)
+{
+	lockdep_assert_rq_held(rq);
+	assert_clock_updated(rq);
+
+	return rq->clock;
+}
+
+static inline u64 rq_clock_task(struct rq *rq)
+{
+	lockdep_assert_rq_held(rq);
+	assert_clock_updated(rq);
+
+	return rq->clock_task;
+}
+
+/**
+ * By default the decay is the default pelt decay period.
+ * The decay shift can change the decay period in
+ * multiples of 32.
+ *  Decay shift		Decay period(ms)
+ *	0			32
+ *	1			64
+ *	2			128
+ *	3			256
+ *	4			512
+ */
+extern int sched_thermal_decay_shift;
+
+static inline u64 rq_clock_thermal(struct rq *rq)
+{
+	return rq_clock_task(rq) >> sched_thermal_decay_shift;
+}
+
+static inline void rq_clock_skip_update(struct rq *rq)
+{
+	lockdep_assert_rq_held(rq);
+	rq->clock_update_flags |= RQCF_REQ_SKIP;
+}
+
+/*
+ * See rt task throttling, which is the only time a skip
+ * request is canceled.
+ */
+static inline void rq_clock_cancel_skipupdate(struct rq *rq)
+{
+	lockdep_assert_rq_held(rq);
+	rq->clock_update_flags &= ~RQCF_REQ_SKIP;
+}
+
+struct rq_flags {
+	unsigned long flags;
+	struct pin_cookie cookie;
+#ifdef CONFIG_SCHED_DEBUG
+	/*
+	 * A copy of (rq::clock_update_flags & RQCF_UPDATED) for the
+	 * current pin context is stashed here in case it needs to be
+	 * restored in rq_repin_lock().
+	 */
+	unsigned int clock_update_flags;
+#endif
+};
+
+extern struct balance_callback balance_push_callback;
+
+/*
+ * Lockdep annotation that avoids accidental unlocks; it's like a
+ * sticky/continuous lockdep_assert_held().
+ *
+ * This avoids code that has access to 'struct rq *rq' (basically everything in
+ * the scheduler) from accidentally unlocking the rq if they do not also have a
+ * copy of the (on-stack) 'struct rq_flags rf'.
+ *
+ * Also see Documentation/locking/lockdep-design.rst.
+ */
+static inline void rq_pin_lock(struct rq *rq, struct rq_flags *rf)
+{
+	rf->cookie = lockdep_pin_lock(__rq_lockp(rq));
+
+#ifdef CONFIG_SCHED_DEBUG
+	rq->clock_update_flags &= (RQCF_REQ_SKIP|RQCF_ACT_SKIP);
+	rf->clock_update_flags = 0;
+#ifdef CONFIG_SMP
+	SCHED_WARN_ON(rq->balance_callback && rq->balance_callback != &balance_push_callback);
+#endif
+#endif
+}
+
+static inline void rq_unpin_lock(struct rq *rq, struct rq_flags *rf)
+{
+#ifdef CONFIG_SCHED_DEBUG
+	if (rq->clock_update_flags > RQCF_ACT_SKIP)
+		rf->clock_update_flags = RQCF_UPDATED;
+#endif
+
+	lockdep_unpin_lock(__rq_lockp(rq), rf->cookie);
+}
+
+static inline void rq_repin_lock(struct rq *rq, struct rq_flags *rf)
+{
+	lockdep_repin_lock(__rq_lockp(rq), rf->cookie);
+
+#ifdef CONFIG_SCHED_DEBUG
+	/*
+	 * Restore the value we stashed in @rf for this pin context.
+	 */
+	rq->clock_update_flags |= rf->clock_update_flags;
+#endif
+}
+
+struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
+	__acquires(rq->lock);
+
+struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
+	__acquires(p->pi_lock)
+	__acquires(rq->lock);
+
+static inline void __task_rq_unlock(struct rq *rq, struct rq_flags *rf)
+	__releases(rq->lock)
+{
+	rq_unpin_lock(rq, rf);
+	raw_spin_rq_unlock(rq);
+}
+
+static inline void
+task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
+	__releases(rq->lock)
+	__releases(p->pi_lock)
+{
+	rq_unpin_lock(rq, rf);
+	raw_spin_rq_unlock(rq);
+	raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
+}
+
+static inline void
+rq_lock_irqsave(struct rq *rq, struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	raw_spin_rq_lock_irqsave(rq, rf->flags);
+	rq_pin_lock(rq, rf);
+}
+
+static inline void
+rq_lock_irq(struct rq *rq, struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	raw_spin_rq_lock_irq(rq);
+	rq_pin_lock(rq, rf);
+}
+
+static inline void
+rq_lock(struct rq *rq, struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	raw_spin_rq_lock(rq);
+	rq_pin_lock(rq, rf);
+}
+
+static inline void
+rq_unlock_irqrestore(struct rq *rq, struct rq_flags *rf)
+	__releases(rq->lock)
+{
+	rq_unpin_lock(rq, rf);
+	raw_spin_rq_unlock_irqrestore(rq, rf->flags);
+}
+
+static inline void
+rq_unlock_irq(struct rq *rq, struct rq_flags *rf)
+	__releases(rq->lock)
+{
+	rq_unpin_lock(rq, rf);
+	raw_spin_rq_unlock_irq(rq);
+}
+
+static inline void
+rq_unlock(struct rq *rq, struct rq_flags *rf)
+	__releases(rq->lock)
+{
+	rq_unpin_lock(rq, rf);
+	raw_spin_rq_unlock(rq);
+}
+
+static inline struct rq *
+this_rq_lock_irq(struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	struct rq *rq;
+
+	local_irq_disable();
+	rq = this_rq();
+	rq_lock(rq, rf);
+	return rq;
+}
+
+#ifdef CONFIG_NUMA
+enum numa_topology_type {
+	NUMA_DIRECT,
+	NUMA_GLUELESS_MESH,
+	NUMA_BACKPLANE,
+};
+extern enum numa_topology_type sched_numa_topology_type;
+extern int sched_max_numa_distance;
+extern bool find_numa_distance(int distance);
+extern void sched_init_numa(int offline_node);
+extern void sched_update_numa(int cpu, bool online);
+extern void sched_domains_numa_masks_set(unsigned int cpu);
+extern void sched_domains_numa_masks_clear(unsigned int cpu);
+extern int sched_numa_find_closest(const struct cpumask *cpus, int cpu);
+#else
+static inline void sched_init_numa(int offline_node) { }
+static inline void sched_update_numa(int cpu, bool online) { }
+static inline void sched_domains_numa_masks_set(unsigned int cpu) { }
+static inline void sched_domains_numa_masks_clear(unsigned int cpu) { }
+static inline int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
+{
+	return nr_cpu_ids;
+}
+#endif
+
+#ifdef CONFIG_NUMA_BALANCING
+/* The regions in numa_faults array from task_struct */
+enum numa_faults_stats {
+	NUMA_MEM = 0,
+	NUMA_CPU,
+	NUMA_MEMBUF,
+	NUMA_CPUBUF
+};
+extern void sched_setnuma(struct task_struct *p, int node);
+extern int migrate_task_to(struct task_struct *p, int cpu);
+extern int migrate_swap(struct task_struct *p, struct task_struct *t,
+			int cpu, int scpu);
+extern void init_numa_balancing(unsigned long clone_flags, struct task_struct *p);
+#else
+static inline void
+init_numa_balancing(unsigned long clone_flags, struct task_struct *p)
+{
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
+#ifdef CONFIG_SMP
+
+static inline void
+queue_balance_callback(struct rq *rq,
+		       struct balance_callback *head,
+		       void (*func)(struct rq *rq))
+{
+	lockdep_assert_rq_held(rq);
+
+	/*
+	 * Don't (re)queue an already queued item; nor queue anything when
+	 * balance_push() is active, see the comment with
+	 * balance_push_callback.
+	 */
+	if (unlikely(head->next || rq->balance_callback == &balance_push_callback))
+		return;
+
+	head->func = func;
+	head->next = rq->balance_callback;
+	rq->balance_callback = head;
+}
+
+#define rcu_dereference_check_sched_domain(p) \
+	rcu_dereference_check((p), \
+			      lockdep_is_held(&sched_domains_mutex))
+
+/*
+ * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
+ * See destroy_sched_domains: call_rcu for details.
+ *
+ * The domain tree of any CPU may only be accessed from within
+ * preempt-disabled sections.
+ */
+#define for_each_domain(cpu, __sd) \
+	for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); \
+			__sd; __sd = __sd->parent)
+
+/**
+ * highest_flag_domain - Return highest sched_domain containing flag.
+ * @cpu:	The CPU whose highest level of sched domain is to
+ *		be returned.
+ * @flag:	The flag to check for the highest sched_domain
+ *		for the given CPU.
+ *
+ * Returns the highest sched_domain of a CPU which contains the given flag.
+ */
+static inline struct sched_domain *highest_flag_domain(int cpu, int flag)
+{
+	struct sched_domain *sd, *hsd = NULL;
+
+	for_each_domain(cpu, sd) {
+		if (!(sd->flags & flag))
+			break;
+		hsd = sd;
+	}
+
+	return hsd;
+}
+
+static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
+{
+	struct sched_domain *sd;
+
+	for_each_domain(cpu, sd) {
+		if (sd->flags & flag)
+			break;
+	}
+
+	return sd;
+}
+
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_llc);
+DECLARE_PER_CPU(int, sd_llc_size);
+DECLARE_PER_CPU(int, sd_llc_id);
+DECLARE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_numa);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
+extern struct static_key_false sched_asym_cpucapacity;
+
+static __always_inline bool sched_asym_cpucap_active(void)
+{
+	return static_branch_unlikely(&sched_asym_cpucapacity);
+}
+
+struct sched_group_capacity {
+	atomic_t		ref;
+	/*
+	 * CPU capacity of this group, SCHED_CAPACITY_SCALE being max capacity
+	 * for a single CPU.
+	 */
+	unsigned long		capacity;
+	unsigned long		min_capacity;		/* Min per-CPU capacity in group */
+	unsigned long		max_capacity;		/* Max per-CPU capacity in group */
+	unsigned long		next_update;
+	int			imbalance;		/* XXX unrelated to capacity but shared group state */
+
+#ifdef CONFIG_SCHED_DEBUG
+	int			id;
+#endif
+
+	unsigned long		cpumask[];		/* Balance mask */
+};
+
+struct sched_group {
+	struct sched_group	*next;			/* Must be a circular list */
+	atomic_t		ref;
+
+	unsigned int		group_weight;
+	struct sched_group_capacity *sgc;
+	int			asym_prefer_cpu;	/* CPU of highest priority in group */
+	int			flags;
+
+	/*
+	 * The CPUs this group covers.
+	 *
+	 * NOTE: this field is variable length. (Allocated dynamically
+	 * by attaching extra space to the end of the structure,
+	 * depending on how many CPUs the kernel has booted up with)
+	 */
+	unsigned long		cpumask[];
+};
+
+static inline struct cpumask *sched_group_span(struct sched_group *sg)
+{
+	return to_cpumask(sg->cpumask);
+}
+
+/*
+ * See build_balance_mask().
+ */
+static inline struct cpumask *group_balance_mask(struct sched_group *sg)
+{
+	return to_cpumask(sg->sgc->cpumask);
+}
+
+extern int group_balance_cpu(struct sched_group *sg);
+
+#ifdef CONFIG_SCHED_DEBUG
+void update_sched_domain_debugfs(void);
+void dirty_sched_domain_sysctl(int cpu);
+#else
+static inline void update_sched_domain_debugfs(void)
+{
+}
+static inline void dirty_sched_domain_sysctl(int cpu)
+{
+}
+#endif
+
+extern int sched_update_scaling(void);
+#endif /* CONFIG_SMP */
+
+#include "stats.h"
+
+#if defined(CONFIG_SCHED_CORE) && defined(CONFIG_SCHEDSTATS)
+
+extern void __sched_core_account_forceidle(struct rq *rq);
+
+static inline void sched_core_account_forceidle(struct rq *rq)
+{
+	if (schedstat_enabled())
+		__sched_core_account_forceidle(rq);
+}
+
+extern void __sched_core_tick(struct rq *rq);
+
+static inline void sched_core_tick(struct rq *rq)
+{
+	if (sched_core_enabled(rq) && schedstat_enabled())
+		__sched_core_tick(rq);
+}
+
+#else
+
+static inline void sched_core_account_forceidle(struct rq *rq) {}
+
+static inline void sched_core_tick(struct rq *rq) {}
+
+#endif /* CONFIG_SCHED_CORE && CONFIG_SCHEDSTATS */
+
+#ifdef CONFIG_CGROUP_SCHED
+
+/*
+ * Return the group to which this tasks belongs.
+ *
+ * We cannot use task_css() and friends because the cgroup subsystem
+ * changes that value before the cgroup_subsys::attach() method is called,
+ * therefore we cannot pin it and might observe the wrong value.
+ *
+ * The same is true for autogroup's p->signal->autogroup->tg, the autogroup
+ * core changes this before calling sched_move_task().
+ *
+ * Instead we use a 'copy' which is updated from sched_move_task() while
+ * holding both task_struct::pi_lock and rq::lock.
+ */
+static inline struct task_group *task_group(struct task_struct *p)
+{
+	return p->sched_task_group;
+}
+
+/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
+static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
+{
+#if defined(CONFIG_FAIR_GROUP_SCHED) || defined(CONFIG_RT_GROUP_SCHED)
+	struct task_group *tg = task_group(p);
+#endif
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	set_task_rq_fair(&p->se, p->se.cfs_rq, tg->cfs_rq[cpu]);
+	p->se.cfs_rq = tg->cfs_rq[cpu];
+	p->se.parent = tg->se[cpu];
+	p->se.depth = tg->se[cpu] ? tg->se[cpu]->depth + 1 : 0;
+#endif
+
+#ifdef CONFIG_RT_GROUP_SCHED
+	p->rt.rt_rq  = tg->rt_rq[cpu];
+	p->rt.parent = tg->rt_se[cpu];
+#endif
+}
+
+#else /* CONFIG_CGROUP_SCHED */
+
+static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
+static inline struct task_group *task_group(struct task_struct *p)
+{
+	return NULL;
+}
+
+#endif /* CONFIG_CGROUP_SCHED */
+
+static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
+{
+	set_task_rq(p, cpu);
+#ifdef CONFIG_SMP
+	/*
+	 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
+	 * successfully executed on another CPU. We must ensure that updates of
+	 * per-task data have been completed by this moment.
+	 */
+	smp_wmb();
+	WRITE_ONCE(task_thread_info(p)->cpu, cpu);
+	p->wake_cpu = cpu;
+#endif
+}
+
+/*
+ * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
+ */
+#ifdef CONFIG_SCHED_DEBUG
+# define const_debug __read_mostly
+#else
+# define const_debug const
+#endif
+
+#define SCHED_FEAT(name, enabled)	\
+	__SCHED_FEAT_##name ,
+
+enum {
+#include "features.h"
+	__SCHED_FEAT_NR,
+};
+
+#undef SCHED_FEAT
+
+#ifdef CONFIG_SCHED_DEBUG
+
+/*
+ * To support run-time toggling of sched features, all the translation units
+ * (but core.c) reference the sysctl_sched_features defined in core.c.
+ */
+extern const_debug unsigned int sysctl_sched_features;
+
+#ifdef CONFIG_JUMP_LABEL
+#define SCHED_FEAT(name, enabled)					\
+static __always_inline bool static_branch_##name(struct static_key *key) \
+{									\
+	return static_key_##enabled(key);				\
+}
+
+#include "features.h"
+#undef SCHED_FEAT
+
+extern struct static_key sched_feat_keys[__SCHED_FEAT_NR];
+#define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x]))
+
+#else /* !CONFIG_JUMP_LABEL */
+
+#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
+
+#endif /* CONFIG_JUMP_LABEL */
+
+#else /* !SCHED_DEBUG */
+
+/*
+ * Each translation unit has its own copy of sysctl_sched_features to allow
+ * constants propagation at compile time and compiler optimization based on
+ * features default.
+ */
+#define SCHED_FEAT(name, enabled)	\
+	(1UL << __SCHED_FEAT_##name) * enabled |
+static const_debug __maybe_unused unsigned int sysctl_sched_features =
+#include "features.h"
+	0;
+#undef SCHED_FEAT
+
+#define sched_feat(x) !!(sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
+
+#endif /* SCHED_DEBUG */
+
+extern struct static_key_false sched_numa_balancing;
+extern struct static_key_false sched_schedstats;
+
+static inline u64 global_rt_period(void)
+{
+	return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
+}
+
+static inline u64 global_rt_runtime(void)
+{
+	if (sysctl_sched_rt_runtime < 0)
+		return RUNTIME_INF;
+
+	return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
+}
+
+static inline int task_current(struct rq *rq, struct task_struct *p)
+{
+	return rq->curr == p;
+}
+
+static inline int task_on_cpu(struct rq *rq, struct task_struct *p)
+{
+#ifdef CONFIG_SMP
+	return p->on_cpu;
+#else
+	return task_current(rq, p);
+#endif
+}
+
+static inline int task_on_rq_queued(struct task_struct *p)
+{
+	return p->on_rq == TASK_ON_RQ_QUEUED;
+}
+
+static inline int task_on_rq_migrating(struct task_struct *p)
+{
+	return READ_ONCE(p->on_rq) == TASK_ON_RQ_MIGRATING;
+}
+
+/* Wake flags. The first three directly map to some SD flag value */
+#define WF_EXEC     0x02 /* Wakeup after exec; maps to SD_BALANCE_EXEC */
+#define WF_FORK     0x04 /* Wakeup after fork; maps to SD_BALANCE_FORK */
+#define WF_TTWU     0x08 /* Wakeup;            maps to SD_BALANCE_WAKE */
+
+#define WF_SYNC     0x10 /* Waker goes to sleep after wakeup */
+#define WF_MIGRATED 0x20 /* Internal use, task got migrated */
+
+#ifdef CONFIG_SMP
+static_assert(WF_EXEC == SD_BALANCE_EXEC);
+static_assert(WF_FORK == SD_BALANCE_FORK);
+static_assert(WF_TTWU == SD_BALANCE_WAKE);
+#endif
+
+/*
+ * To aid in avoiding the subversion of "niceness" due to uneven distribution
+ * of tasks with abnormal "nice" values across CPUs the contribution that
+ * each task makes to its run queue's load is weighted according to its
+ * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
+ * scaled version of the new time slice allocation that they receive on time
+ * slice expiry etc.
+ */
+
+#define WEIGHT_IDLEPRIO		3
+#define WMULT_IDLEPRIO		1431655765
+
+extern const int		sched_prio_to_weight[40];
+extern const u32		sched_prio_to_wmult[40];
+
+/*
+ * {de,en}queue flags:
+ *
+ * DEQUEUE_SLEEP  - task is no longer runnable
+ * ENQUEUE_WAKEUP - task just became runnable
+ *
+ * SAVE/RESTORE - an otherwise spurious dequeue/enqueue, done to ensure tasks
+ *                are in a known state which allows modification. Such pairs
+ *                should preserve as much state as possible.
+ *
+ * MOVE - paired with SAVE/RESTORE, explicitly does not preserve the location
+ *        in the runqueue.
+ *
+ * ENQUEUE_HEAD      - place at front of runqueue (tail if not specified)
+ * ENQUEUE_REPLENISH - CBS (replenish runtime and postpone deadline)
+ * ENQUEUE_MIGRATED  - the task was migrated during wakeup
+ *
+ */
+
+#define DEQUEUE_SLEEP		0x01
+#define DEQUEUE_SAVE		0x02 /* Matches ENQUEUE_RESTORE */
+#define DEQUEUE_MOVE		0x04 /* Matches ENQUEUE_MOVE */
+#define DEQUEUE_NOCLOCK		0x08 /* Matches ENQUEUE_NOCLOCK */
+
+#define ENQUEUE_WAKEUP		0x01
+#define ENQUEUE_RESTORE		0x02
+#define ENQUEUE_MOVE		0x04
+#define ENQUEUE_NOCLOCK		0x08
+
+#define ENQUEUE_HEAD		0x10
+#define ENQUEUE_REPLENISH	0x20
+#ifdef CONFIG_SMP
+#define ENQUEUE_MIGRATED	0x40
+#else
+#define ENQUEUE_MIGRATED	0x00
+#endif
+
+#define RETRY_TASK		((void *)-1UL)
+
+struct sched_class {
+
+#ifdef CONFIG_UCLAMP_TASK
+	int uclamp_enabled;
+#endif
+
+	void (*enqueue_task) (struct rq *rq, struct task_struct *p, int flags);
+	void (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags);
+	void (*yield_task)   (struct rq *rq);
+	bool (*yield_to_task)(struct rq *rq, struct task_struct *p);
+
+	void (*check_preempt_curr)(struct rq *rq, struct task_struct *p, int flags);
+
+	struct task_struct *(*pick_next_task)(struct rq *rq);
+
+	void (*put_prev_task)(struct rq *rq, struct task_struct *p);
+	void (*set_next_task)(struct rq *rq, struct task_struct *p, bool first);
+
+#ifdef CONFIG_SMP
+	int (*balance)(struct rq *rq, struct task_struct *prev, struct rq_flags *rf);
+	int  (*select_task_rq)(struct task_struct *p, int task_cpu, int flags);
+
+	struct task_struct * (*pick_task)(struct rq *rq);
+
+	void (*migrate_task_rq)(struct task_struct *p, int new_cpu);
+
+	void (*task_woken)(struct rq *this_rq, struct task_struct *task);
+
+	void (*set_cpus_allowed)(struct task_struct *p,
+				 const struct cpumask *newmask,
+				 u32 flags);
+
+	void (*rq_online)(struct rq *rq);
+	void (*rq_offline)(struct rq *rq);
+
+	struct rq *(*find_lock_rq)(struct task_struct *p, struct rq *rq);
+#endif
+
+	void (*task_tick)(struct rq *rq, struct task_struct *p, int queued);
+	void (*task_fork)(struct task_struct *p);
+	void (*task_dead)(struct task_struct *p);
+
+	/*
+	 * The switched_from() call is allowed to drop rq->lock, therefore we
+	 * cannot assume the switched_from/switched_to pair is serialized by
+	 * rq->lock. They are however serialized by p->pi_lock.
+	 */
+	void (*switched_from)(struct rq *this_rq, struct task_struct *task);
+	void (*switched_to)  (struct rq *this_rq, struct task_struct *task);
+	void (*prio_changed) (struct rq *this_rq, struct task_struct *task,
+			      int oldprio);
+
+	unsigned int (*get_rr_interval)(struct rq *rq,
+					struct task_struct *task);
+
+	void (*update_curr)(struct rq *rq);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	void (*task_change_group)(struct task_struct *p);
+#endif
+};
+
+static inline void put_prev_task(struct rq *rq, struct task_struct *prev)
+{
+	WARN_ON_ONCE(rq->curr != prev);
+	prev->sched_class->put_prev_task(rq, prev);
+}
+
+static inline void set_next_task(struct rq *rq, struct task_struct *next)
+{
+	next->sched_class->set_next_task(rq, next, false);
+}
+
+
+/*
+ * Helper to define a sched_class instance; each one is placed in a separate
+ * section which is ordered by the linker script:
+ *
+ *   include/asm-generic/vmlinux.lds.h
+ *
+ * *CAREFUL* they are laid out in *REVERSE* order!!!
+ *
+ * Also enforce alignment on the instance, not the type, to guarantee layout.
+ */
+#define DEFINE_SCHED_CLASS(name) \
+const struct sched_class name##_sched_class \
+	__aligned(__alignof__(struct sched_class)) \
+	__section("__" #name "_sched_class")
+
+/* Defined in include/asm-generic/vmlinux.lds.h */
+extern struct sched_class __sched_class_highest[];
+extern struct sched_class __sched_class_lowest[];
+
+#define for_class_range(class, _from, _to) \
+	for (class = (_from); class < (_to); class++)
+
+#define for_each_class(class) \
+	for_class_range(class, __sched_class_highest, __sched_class_lowest)
+
+#define sched_class_above(_a, _b)	((_a) < (_b))
+
+extern const struct sched_class stop_sched_class;
+extern const struct sched_class dl_sched_class;
+extern const struct sched_class rt_sched_class;
+extern const struct sched_class fair_sched_class;
+extern const struct sched_class idle_sched_class;
+
+static inline bool sched_stop_runnable(struct rq *rq)
+{
+	return rq->stop && task_on_rq_queued(rq->stop);
+}
+
+static inline bool sched_dl_runnable(struct rq *rq)
+{
+	return rq->dl.dl_nr_running > 0;
+}
+
+static inline bool sched_rt_runnable(struct rq *rq)
+{
+	return rq->rt.rt_queued > 0;
+}
+
+static inline bool sched_fair_runnable(struct rq *rq)
+{
+	return rq->cfs.nr_running > 0;
+}
+
+extern struct task_struct *pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf);
+extern struct task_struct *pick_next_task_idle(struct rq *rq);
+
+#define SCA_CHECK		0x01
+#define SCA_MIGRATE_DISABLE	0x02
+#define SCA_MIGRATE_ENABLE	0x04
+#define SCA_USER		0x08
+
+#ifdef CONFIG_SMP
+
+extern void update_group_capacity(struct sched_domain *sd, int cpu);
+
+extern void trigger_load_balance(struct rq *rq);
+
+extern void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask, u32 flags);
+
+static inline struct task_struct *get_push_task(struct rq *rq)
+{
+	struct task_struct *p = rq->curr;
+
+	lockdep_assert_rq_held(rq);
+
+	if (rq->push_busy)
+		return NULL;
+
+	if (p->nr_cpus_allowed == 1)
+		return NULL;
+
+	if (p->migration_disabled)
+		return NULL;
+
+	rq->push_busy = true;
+	return get_task_struct(p);
+}
+
+extern int push_cpu_stop(void *arg);
+
+#endif
+
+#ifdef CONFIG_CPU_IDLE
+static inline void idle_set_state(struct rq *rq,
+				  struct cpuidle_state *idle_state)
+{
+	rq->idle_state = idle_state;
+}
+
+static inline struct cpuidle_state *idle_get_state(struct rq *rq)
+{
+	SCHED_WARN_ON(!rcu_read_lock_held());
+
+	return rq->idle_state;
+}
+#else
+static inline void idle_set_state(struct rq *rq,
+				  struct cpuidle_state *idle_state)
+{
+}
+
+static inline struct cpuidle_state *idle_get_state(struct rq *rq)
+{
+	return NULL;
+}
+#endif
+
+extern void schedule_idle(void);
+
+extern void sysrq_sched_debug_show(void);
+extern void sched_init_granularity(void);
+extern void update_max_interval(void);
+
+extern void init_sched_dl_class(void);
+extern void init_sched_rt_class(void);
+extern void init_sched_fair_class(void);
+
+extern void reweight_task(struct task_struct *p, int prio);
+
+extern void resched_curr(struct rq *rq);
+extern void resched_cpu(int cpu);
+
+extern struct rt_bandwidth def_rt_bandwidth;
+extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime);
+extern bool sched_rt_bandwidth_account(struct rt_rq *rt_rq);
+
+extern void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime);
+extern void init_dl_task_timer(struct sched_dl_entity *dl_se);
+extern void init_dl_inactive_task_timer(struct sched_dl_entity *dl_se);
+
+#define BW_SHIFT		20
+#define BW_UNIT			(1 << BW_SHIFT)
+#define RATIO_SHIFT		8
+#define MAX_BW_BITS		(64 - BW_SHIFT)
+#define MAX_BW			((1ULL << MAX_BW_BITS) - 1)
+unsigned long to_ratio(u64 period, u64 runtime);
+
+extern void init_entity_runnable_average(struct sched_entity *se);
+extern void post_init_entity_util_avg(struct task_struct *p);
+
+#ifdef CONFIG_NO_HZ_FULL
+extern bool sched_can_stop_tick(struct rq *rq);
+extern int __init sched_tick_offload_init(void);
+
+/*
+ * Tick may be needed by tasks in the runqueue depending on their policy and
+ * requirements. If tick is needed, lets send the target an IPI to kick it out of
+ * nohz mode if necessary.
+ */
+static inline void sched_update_tick_dependency(struct rq *rq)
+{
+	int cpu = cpu_of(rq);
+
+	if (!tick_nohz_full_cpu(cpu))
+		return;
+
+	if (sched_can_stop_tick(rq))
+		tick_nohz_dep_clear_cpu(cpu, TICK_DEP_BIT_SCHED);
+	else
+		tick_nohz_dep_set_cpu(cpu, TICK_DEP_BIT_SCHED);
+}
+#else
+static inline int sched_tick_offload_init(void) { return 0; }
+static inline void sched_update_tick_dependency(struct rq *rq) { }
+#endif
+
+static inline void add_nr_running(struct rq *rq, unsigned count)
+{
+	unsigned prev_nr = rq->nr_running;
+
+	rq->nr_running = prev_nr + count;
+	if (trace_sched_update_nr_running_tp_enabled()) {
+		call_trace_sched_update_nr_running(rq, count);
+	}
+
+#ifdef CONFIG_SMP
+	if (prev_nr < 2 && rq->nr_running >= 2) {
+		if (!READ_ONCE(rq->rd->overload))
+			WRITE_ONCE(rq->rd->overload, 1);
+	}
+#endif
+
+	sched_update_tick_dependency(rq);
+}
+
+static inline void sub_nr_running(struct rq *rq, unsigned count)
+{
+	rq->nr_running -= count;
+	if (trace_sched_update_nr_running_tp_enabled()) {
+		call_trace_sched_update_nr_running(rq, -count);
+	}
+
+	/* Check if we still need preemption */
+	sched_update_tick_dependency(rq);
+}
+
+extern void activate_task(struct rq *rq, struct task_struct *p, int flags);
+extern void deactivate_task(struct rq *rq, struct task_struct *p, int flags);
+
+extern void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags);
+
+#ifdef CONFIG_PREEMPT_RT
+#define SCHED_NR_MIGRATE_BREAK 8
+#else
+#define SCHED_NR_MIGRATE_BREAK 32
+#endif
+
+extern const_debug unsigned int sysctl_sched_nr_migrate;
+extern const_debug unsigned int sysctl_sched_migration_cost;
+
+#ifdef CONFIG_SCHED_DEBUG
+extern unsigned int sysctl_sched_latency;
+extern unsigned int sysctl_sched_min_granularity;
+extern unsigned int sysctl_sched_idle_min_granularity;
+extern unsigned int sysctl_sched_wakeup_granularity;
+extern int sysctl_resched_latency_warn_ms;
+extern int sysctl_resched_latency_warn_once;
+
+extern unsigned int sysctl_sched_tunable_scaling;
+
+extern unsigned int sysctl_numa_balancing_scan_delay;
+extern unsigned int sysctl_numa_balancing_scan_period_min;
+extern unsigned int sysctl_numa_balancing_scan_period_max;
+extern unsigned int sysctl_numa_balancing_scan_size;
+extern unsigned int sysctl_numa_balancing_hot_threshold;
+#endif
+
+#ifdef CONFIG_SCHED_HRTICK
+
+/*
+ * Use hrtick when:
+ *  - enabled by features
+ *  - hrtimer is actually high res
+ */
+static inline int hrtick_enabled(struct rq *rq)
+{
+	if (!cpu_active(cpu_of(rq)))
+		return 0;
+	return hrtimer_is_hres_active(&rq->hrtick_timer);
+}
+
+static inline int hrtick_enabled_fair(struct rq *rq)
+{
+	if (!sched_feat(HRTICK))
+		return 0;
+	return hrtick_enabled(rq);
+}
+
+static inline int hrtick_enabled_dl(struct rq *rq)
+{
+	if (!sched_feat(HRTICK_DL))
+		return 0;
+	return hrtick_enabled(rq);
+}
+
+void hrtick_start(struct rq *rq, u64 delay);
+
+#else
+
+static inline int hrtick_enabled_fair(struct rq *rq)
+{
+	return 0;
+}
+
+static inline int hrtick_enabled_dl(struct rq *rq)
+{
+	return 0;
+}
+
+static inline int hrtick_enabled(struct rq *rq)
+{
+	return 0;
+}
+
+#endif /* CONFIG_SCHED_HRTICK */
+
+#ifndef arch_scale_freq_tick
+static __always_inline
+void arch_scale_freq_tick(void)
+{
+}
+#endif
+
+#ifndef arch_scale_freq_capacity
+/**
+ * arch_scale_freq_capacity - get the frequency scale factor of a given CPU.
+ * @cpu: the CPU in question.
+ *
+ * Return: the frequency scale factor normalized against SCHED_CAPACITY_SCALE, i.e.
+ *
+ *     f_curr
+ *     ------ * SCHED_CAPACITY_SCALE
+ *     f_max
+ */
+static __always_inline
+unsigned long arch_scale_freq_capacity(int cpu)
+{
+	return SCHED_CAPACITY_SCALE;
+}
+#endif
+
+#ifdef CONFIG_SCHED_DEBUG
+/*
+ * In double_lock_balance()/double_rq_lock(), we use raw_spin_rq_lock() to
+ * acquire rq lock instead of rq_lock(). So at the end of these two functions
+ * we need to call double_rq_clock_clear_update() to clear RQCF_UPDATED of
+ * rq->clock_update_flags to avoid the WARN_DOUBLE_CLOCK warning.
+ */
+static inline void double_rq_clock_clear_update(struct rq *rq1, struct rq *rq2)
+{
+	rq1->clock_update_flags &= (RQCF_REQ_SKIP|RQCF_ACT_SKIP);
+	/* rq1 == rq2 for !CONFIG_SMP, so just clear RQCF_UPDATED once. */
+#ifdef CONFIG_SMP
+	rq2->clock_update_flags &= (RQCF_REQ_SKIP|RQCF_ACT_SKIP);
+#endif
+}
+#else
+static inline void double_rq_clock_clear_update(struct rq *rq1, struct rq *rq2) {}
+#endif
+
+#ifdef CONFIG_SMP
+
+static inline bool rq_order_less(struct rq *rq1, struct rq *rq2)
+{
+#ifdef CONFIG_SCHED_CORE
+	/*
+	 * In order to not have {0,2},{1,3} turn into into an AB-BA,
+	 * order by core-id first and cpu-id second.
+	 *
+	 * Notably:
+	 *
+	 *	double_rq_lock(0,3); will take core-0, core-1 lock
+	 *	double_rq_lock(1,2); will take core-1, core-0 lock
+	 *
+	 * when only cpu-id is considered.
+	 */
+	if (rq1->core->cpu < rq2->core->cpu)
+		return true;
+	if (rq1->core->cpu > rq2->core->cpu)
+		return false;
+
+	/*
+	 * __sched_core_flip() relies on SMT having cpu-id lock order.
+	 */
+#endif
+	return rq1->cpu < rq2->cpu;
+}
+
+extern void double_rq_lock(struct rq *rq1, struct rq *rq2);
+
+#ifdef CONFIG_PREEMPTION
+
+/*
+ * fair double_lock_balance: Safely acquires both rq->locks in a fair
+ * way at the expense of forcing extra atomic operations in all
+ * invocations.  This assures that the double_lock is acquired using the
+ * same underlying policy as the spinlock_t on this architecture, which
+ * reduces latency compared to the unfair variant below.  However, it
+ * also adds more overhead and therefore may reduce throughput.
+ */
+static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
+	__releases(this_rq->lock)
+	__acquires(busiest->lock)
+	__acquires(this_rq->lock)
+{
+	raw_spin_rq_unlock(this_rq);
+	double_rq_lock(this_rq, busiest);
+
+	return 1;
+}
+
+#else
+/*
+ * Unfair double_lock_balance: Optimizes throughput at the expense of
+ * latency by eliminating extra atomic operations when the locks are
+ * already in proper order on entry.  This favors lower CPU-ids and will
+ * grant the double lock to lower CPUs over higher ids under contention,
+ * regardless of entry order into the function.
+ */
+static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
+	__releases(this_rq->lock)
+	__acquires(busiest->lock)
+	__acquires(this_rq->lock)
+{
+	if (__rq_lockp(this_rq) == __rq_lockp(busiest) ||
+	    likely(raw_spin_rq_trylock(busiest))) {
+		double_rq_clock_clear_update(this_rq, busiest);
+		return 0;
+	}
+
+	if (rq_order_less(this_rq, busiest)) {
+		raw_spin_rq_lock_nested(busiest, SINGLE_DEPTH_NESTING);
+		double_rq_clock_clear_update(this_rq, busiest);
+		return 0;
+	}
+
+	raw_spin_rq_unlock(this_rq);
+	double_rq_lock(this_rq, busiest);
+
+	return 1;
+}
+
+#endif /* CONFIG_PREEMPTION */
+
+/*
+ * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
+ */
+static inline int double_lock_balance(struct rq *this_rq, struct rq *busiest)
+{
+	lockdep_assert_irqs_disabled();
+
+	return _double_lock_balance(this_rq, busiest);
+}
+
+static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
+	__releases(busiest->lock)
+{
+	if (__rq_lockp(this_rq) != __rq_lockp(busiest))
+		raw_spin_rq_unlock(busiest);
+	lock_set_subclass(&__rq_lockp(this_rq)->dep_map, 0, _RET_IP_);
+}
+
+static inline void double_lock(spinlock_t *l1, spinlock_t *l2)
+{
+	if (l1 > l2)
+		swap(l1, l2);
+
+	spin_lock(l1);
+	spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
+}
+
+static inline void double_lock_irq(spinlock_t *l1, spinlock_t *l2)
+{
+	if (l1 > l2)
+		swap(l1, l2);
+
+	spin_lock_irq(l1);
+	spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
+}
+
+static inline void double_raw_lock(raw_spinlock_t *l1, raw_spinlock_t *l2)
+{
+	if (l1 > l2)
+		swap(l1, l2);
+
+	raw_spin_lock(l1);
+	raw_spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
+}
+
+/*
+ * double_rq_unlock - safely unlock two runqueues
+ *
+ * Note this does not restore interrupts like task_rq_unlock,
+ * you need to do so manually after calling.
+ */
+static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
+	__releases(rq1->lock)
+	__releases(rq2->lock)
+{
+	if (__rq_lockp(rq1) != __rq_lockp(rq2))
+		raw_spin_rq_unlock(rq2);
+	else
+		__release(rq2->lock);
+	raw_spin_rq_unlock(rq1);
+}
+
+extern void set_rq_online (struct rq *rq);
+extern void set_rq_offline(struct rq *rq);
+extern bool sched_smp_initialized;
+
+#else /* CONFIG_SMP */
+
+/*
+ * double_rq_lock - safely lock two runqueues
+ *
+ * Note this does not disable interrupts like task_rq_lock,
+ * you need to do so manually before calling.
+ */
+static inline void double_rq_lock(struct rq *rq1, struct rq *rq2)
+	__acquires(rq1->lock)
+	__acquires(rq2->lock)
+{
+	WARN_ON_ONCE(!irqs_disabled());
+	WARN_ON_ONCE(rq1 != rq2);
+	raw_spin_rq_lock(rq1);
+	__acquire(rq2->lock);	/* Fake it out ;) */
+	double_rq_clock_clear_update(rq1, rq2);
+}
+
+/*
+ * double_rq_unlock - safely unlock two runqueues
+ *
+ * Note this does not restore interrupts like task_rq_unlock,
+ * you need to do so manually after calling.
+ */
+static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
+	__releases(rq1->lock)
+	__releases(rq2->lock)
+{
+	WARN_ON_ONCE(rq1 != rq2);
+	raw_spin_rq_unlock(rq1);
+	__release(rq2->lock);
+}
+
+#endif
+
+extern struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq);
+extern struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq);
+
+#ifdef	CONFIG_SCHED_DEBUG
+extern bool sched_debug_verbose;
+
+extern void print_cfs_stats(struct seq_file *m, int cpu);
+extern void print_rt_stats(struct seq_file *m, int cpu);
+extern void print_dl_stats(struct seq_file *m, int cpu);
+extern void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq);
+extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq);
+extern void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq);
+
+extern void resched_latency_warn(int cpu, u64 latency);
+#ifdef CONFIG_NUMA_BALANCING
+extern void
+show_numa_stats(struct task_struct *p, struct seq_file *m);
+extern void
+print_numa_stats(struct seq_file *m, int node, unsigned long tsf,
+	unsigned long tpf, unsigned long gsf, unsigned long gpf);
+#endif /* CONFIG_NUMA_BALANCING */
+#else
+static inline void resched_latency_warn(int cpu, u64 latency) {}
+#endif /* CONFIG_SCHED_DEBUG */
+
+extern void init_cfs_rq(struct cfs_rq *cfs_rq);
+extern void init_rt_rq(struct rt_rq *rt_rq);
+extern void init_dl_rq(struct dl_rq *dl_rq);
+
+extern void cfs_bandwidth_usage_inc(void);
+extern void cfs_bandwidth_usage_dec(void);
+
+#ifdef CONFIG_NO_HZ_COMMON
+#define NOHZ_BALANCE_KICK_BIT	0
+#define NOHZ_STATS_KICK_BIT	1
+#define NOHZ_NEWILB_KICK_BIT	2
+#define NOHZ_NEXT_KICK_BIT	3
+
+/* Run rebalance_domains() */
+#define NOHZ_BALANCE_KICK	BIT(NOHZ_BALANCE_KICK_BIT)
+/* Update blocked load */
+#define NOHZ_STATS_KICK		BIT(NOHZ_STATS_KICK_BIT)
+/* Update blocked load when entering idle */
+#define NOHZ_NEWILB_KICK	BIT(NOHZ_NEWILB_KICK_BIT)
+/* Update nohz.next_balance */
+#define NOHZ_NEXT_KICK		BIT(NOHZ_NEXT_KICK_BIT)
+
+#define NOHZ_KICK_MASK	(NOHZ_BALANCE_KICK | NOHZ_STATS_KICK | NOHZ_NEXT_KICK)
+
+#define nohz_flags(cpu)	(&cpu_rq(cpu)->nohz_flags)
+
+extern void nohz_balance_exit_idle(struct rq *rq);
+#else
+static inline void nohz_balance_exit_idle(struct rq *rq) { }
+#endif
+
+#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
+extern void nohz_run_idle_balance(int cpu);
+#else
+static inline void nohz_run_idle_balance(int cpu) { }
+#endif
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+struct irqtime {
+	u64			total;
+	u64			tick_delta;
+	u64			irq_start_time;
+	struct u64_stats_sync	sync;
+};
+
+DECLARE_PER_CPU(struct irqtime, cpu_irqtime);
+
+/*
+ * Returns the irqtime minus the softirq time computed by ksoftirqd.
+ * Otherwise ksoftirqd's sum_exec_runtime is subtracted its own runtime
+ * and never move forward.
+ */
+static inline u64 irq_time_read(int cpu)
+{
+	struct irqtime *irqtime = &per_cpu(cpu_irqtime, cpu);
+	unsigned int seq;
+	u64 total;
+
+	do {
+		seq = __u64_stats_fetch_begin(&irqtime->sync);
+		total = irqtime->total;
+	} while (__u64_stats_fetch_retry(&irqtime->sync, seq));
+
+	return total;
+}
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+#ifdef CONFIG_CPU_FREQ
+DECLARE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
+
+/**
+ * cpufreq_update_util - Take a note about CPU utilization changes.
+ * @rq: Runqueue to carry out the update for.
+ * @flags: Update reason flags.
+ *
+ * This function is called by the scheduler on the CPU whose utilization is
+ * being updated.
+ *
+ * It can only be called from RCU-sched read-side critical sections.
+ *
+ * The way cpufreq is currently arranged requires it to evaluate the CPU
+ * performance state (frequency/voltage) on a regular basis to prevent it from
+ * being stuck in a completely inadequate performance level for too long.
+ * That is not guaranteed to happen if the updates are only triggered from CFS
+ * and DL, though, because they may not be coming in if only RT tasks are
+ * active all the time (or there are RT tasks only).
+ *
+ * As a workaround for that issue, this function is called periodically by the
+ * RT sched class to trigger extra cpufreq updates to prevent it from stalling,
+ * but that really is a band-aid.  Going forward it should be replaced with
+ * solutions targeted more specifically at RT tasks.
+ */
+static inline void cpufreq_update_util(struct rq *rq, unsigned int flags)
+{
+	struct update_util_data *data;
+
+	data = rcu_dereference_sched(*per_cpu_ptr(&cpufreq_update_util_data,
+						  cpu_of(rq)));
+	if (data)
+		data->func(data, rq_clock(rq), flags);
+}
+#else
+static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
+#endif /* CONFIG_CPU_FREQ */
+
+#ifdef arch_scale_freq_capacity
+# ifndef arch_scale_freq_invariant
+#  define arch_scale_freq_invariant()	true
+# endif
+#else
+# define arch_scale_freq_invariant()	false
+#endif
+
+#ifdef CONFIG_SMP
+static inline unsigned long capacity_orig_of(int cpu)
+{
+	return cpu_rq(cpu)->cpu_capacity_orig;
+}
+
+/**
+ * enum cpu_util_type - CPU utilization type
+ * @FREQUENCY_UTIL:	Utilization used to select frequency
+ * @ENERGY_UTIL:	Utilization used during energy calculation
+ *
+ * The utilization signals of all scheduling classes (CFS/RT/DL) and IRQ time
+ * need to be aggregated differently depending on the usage made of them. This
+ * enum is used within effective_cpu_util() to differentiate the types of
+ * utilization expected by the callers, and adjust the aggregation accordingly.
+ */
+enum cpu_util_type {
+	FREQUENCY_UTIL,
+	ENERGY_UTIL,
+};
+
+unsigned long effective_cpu_util(int cpu, unsigned long util_cfs,
+				 enum cpu_util_type type,
+				 struct task_struct *p);
+
+/*
+ * Verify the fitness of task @p to run on @cpu taking into account the
+ * CPU original capacity and the runtime/deadline ratio of the task.
+ *
+ * The function will return true if the original capacity of @cpu is
+ * greater than or equal to task's deadline density right shifted by
+ * (BW_SHIFT - SCHED_CAPACITY_SHIFT) and false otherwise.
+ */
+static inline bool dl_task_fits_capacity(struct task_struct *p, int cpu)
+{
+	unsigned long cap = arch_scale_cpu_capacity(cpu);
+
+	return cap >= p->dl.dl_density >> (BW_SHIFT - SCHED_CAPACITY_SHIFT);
+}
+
+static inline unsigned long cpu_bw_dl(struct rq *rq)
+{
+	return (rq->dl.running_bw * SCHED_CAPACITY_SCALE) >> BW_SHIFT;
+}
+
+static inline unsigned long cpu_util_dl(struct rq *rq)
+{
+	return READ_ONCE(rq->avg_dl.util_avg);
+}
+
+/**
+ * cpu_util_cfs() - Estimates the amount of CPU capacity used by CFS tasks.
+ * @cpu: the CPU to get the utilization for.
+ *
+ * The unit of the return value must be the same as the one of CPU capacity
+ * so that CPU utilization can be compared with CPU capacity.
+ *
+ * CPU utilization is the sum of running time of runnable tasks plus the
+ * recent utilization of currently non-runnable tasks on that CPU.
+ * It represents the amount of CPU capacity currently used by CFS tasks in
+ * the range [0..max CPU capacity] with max CPU capacity being the CPU
+ * capacity at f_max.
+ *
+ * The estimated CPU utilization is defined as the maximum between CPU
+ * utilization and sum of the estimated utilization of the currently
+ * runnable tasks on that CPU. It preserves a utilization "snapshot" of
+ * previously-executed tasks, which helps better deduce how busy a CPU will
+ * be when a long-sleeping task wakes up. The contribution to CPU utilization
+ * of such a task would be significantly decayed at this point of time.
+ *
+ * CPU utilization can be higher than the current CPU capacity
+ * (f_curr/f_max * max CPU capacity) or even the max CPU capacity because
+ * of rounding errors as well as task migrations or wakeups of new tasks.
+ * CPU utilization has to be capped to fit into the [0..max CPU capacity]
+ * range. Otherwise a group of CPUs (CPU0 util = 121% + CPU1 util = 80%)
+ * could be seen as over-utilized even though CPU1 has 20% of spare CPU
+ * capacity. CPU utilization is allowed to overshoot current CPU capacity
+ * though since this is useful for predicting the CPU capacity required
+ * after task migrations (scheduler-driven DVFS).
+ *
+ * Return: (Estimated) utilization for the specified CPU.
+ */
+static inline unsigned long cpu_util_cfs(int cpu)
+{
+	struct cfs_rq *cfs_rq;
+	unsigned long util;
+
+	cfs_rq = &cpu_rq(cpu)->cfs;
+	util = READ_ONCE(cfs_rq->avg.util_avg);
+
+	if (sched_feat(UTIL_EST)) {
+		util = max_t(unsigned long, util,
+			     READ_ONCE(cfs_rq->avg.util_est.enqueued));
+	}
+
+	return min(util, capacity_orig_of(cpu));
+}
+
+static inline unsigned long cpu_util_rt(struct rq *rq)
+{
+	return READ_ONCE(rq->avg_rt.util_avg);
+}
+#endif
+
+#ifdef CONFIG_UCLAMP_TASK
+unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id);
+
+static inline unsigned long uclamp_rq_get(struct rq *rq,
+					  enum uclamp_id clamp_id)
+{
+	return READ_ONCE(rq->uclamp[clamp_id].value);
+}
+
+static inline void uclamp_rq_set(struct rq *rq, enum uclamp_id clamp_id,
+				 unsigned int value)
+{
+	WRITE_ONCE(rq->uclamp[clamp_id].value, value);
+}
+
+static inline bool uclamp_rq_is_idle(struct rq *rq)
+{
+	return rq->uclamp_flags & UCLAMP_FLAG_IDLE;
+}
+
+/**
+ * uclamp_rq_util_with - clamp @util with @rq and @p effective uclamp values.
+ * @rq:		The rq to clamp against. Must not be NULL.
+ * @util:	The util value to clamp.
+ * @p:		The task to clamp against. Can be NULL if you want to clamp
+ *		against @rq only.
+ *
+ * Clamps the passed @util to the max(@rq, @p) effective uclamp values.
+ *
+ * If sched_uclamp_used static key is disabled, then just return the util
+ * without any clamping since uclamp aggregation at the rq level in the fast
+ * path is disabled, rendering this operation a NOP.
+ *
+ * Use uclamp_eff_value() if you don't care about uclamp values at rq level. It
+ * will return the correct effective uclamp value of the task even if the
+ * static key is disabled.
+ */
+static __always_inline
+unsigned long uclamp_rq_util_with(struct rq *rq, unsigned long util,
+				  struct task_struct *p)
+{
+	unsigned long min_util = 0;
+	unsigned long max_util = 0;
+
+	if (!static_branch_likely(&sched_uclamp_used))
+		return util;
+
+	if (p) {
+		min_util = uclamp_eff_value(p, UCLAMP_MIN);
+		max_util = uclamp_eff_value(p, UCLAMP_MAX);
+
+		/*
+		 * Ignore last runnable task's max clamp, as this task will
+		 * reset it. Similarly, no need to read the rq's min clamp.
+		 */
+		if (uclamp_rq_is_idle(rq))
+			goto out;
+	}
+
+	min_util = max_t(unsigned long, min_util, uclamp_rq_get(rq, UCLAMP_MIN));
+	max_util = max_t(unsigned long, max_util, uclamp_rq_get(rq, UCLAMP_MAX));
+out:
+	/*
+	 * Since CPU's {min,max}_util clamps are MAX aggregated considering
+	 * RUNNABLE tasks with _different_ clamps, we can end up with an
+	 * inversion. Fix it now when the clamps are applied.
+	 */
+	if (unlikely(min_util >= max_util))
+		return min_util;
+
+	return clamp(util, min_util, max_util);
+}
+
+/* Is the rq being capped/throttled by uclamp_max? */
+static inline bool uclamp_rq_is_capped(struct rq *rq)
+{
+	unsigned long rq_util;
+	unsigned long max_util;
+
+	if (!static_branch_likely(&sched_uclamp_used))
+		return false;
+
+	rq_util = cpu_util_cfs(cpu_of(rq)) + cpu_util_rt(rq);
+	max_util = READ_ONCE(rq->uclamp[UCLAMP_MAX].value);
+
+	return max_util != SCHED_CAPACITY_SCALE && rq_util >= max_util;
+}
+
+/*
+ * When uclamp is compiled in, the aggregation at rq level is 'turned off'
+ * by default in the fast path and only gets turned on once userspace performs
+ * an operation that requires it.
+ *
+ * Returns true if userspace opted-in to use uclamp and aggregation at rq level
+ * hence is active.
+ */
+static inline bool uclamp_is_used(void)
+{
+	return static_branch_likely(&sched_uclamp_used);
+}
+#else /* CONFIG_UCLAMP_TASK */
+static inline unsigned long uclamp_eff_value(struct task_struct *p,
+					     enum uclamp_id clamp_id)
+{
+	if (clamp_id == UCLAMP_MIN)
+		return 0;
+
+	return SCHED_CAPACITY_SCALE;
+}
+
+static inline
+unsigned long uclamp_rq_util_with(struct rq *rq, unsigned long util,
+				  struct task_struct *p)
+{
+	return util;
+}
+
+static inline bool uclamp_rq_is_capped(struct rq *rq) { return false; }
+
+static inline bool uclamp_is_used(void)
+{
+	return false;
+}
+
+static inline unsigned long uclamp_rq_get(struct rq *rq,
+					  enum uclamp_id clamp_id)
+{
+	if (clamp_id == UCLAMP_MIN)
+		return 0;
+
+	return SCHED_CAPACITY_SCALE;
+}
+
+static inline void uclamp_rq_set(struct rq *rq, enum uclamp_id clamp_id,
+				 unsigned int value)
+{
+}
+
+static inline bool uclamp_rq_is_idle(struct rq *rq)
+{
+	return false;
+}
+#endif /* CONFIG_UCLAMP_TASK */
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+static inline unsigned long cpu_util_irq(struct rq *rq)
+{
+	return rq->avg_irq.util_avg;
+}
+
+static inline
+unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned long max)
+{
+	util *= (max - irq);
+	util /= max;
+
+	return util;
+
+}
+#else
+static inline unsigned long cpu_util_irq(struct rq *rq)
+{
+	return 0;
+}
+
+static inline
+unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned long max)
+{
+	return util;
+}
+#endif
+
+#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
+
+#define perf_domain_span(pd) (to_cpumask(((pd)->em_pd->cpus)))
+
+DECLARE_STATIC_KEY_FALSE(sched_energy_present);
+
+static inline bool sched_energy_enabled(void)
+{
+	return static_branch_unlikely(&sched_energy_present);
+}
+
+#else /* ! (CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL) */
+
+#define perf_domain_span(pd) NULL
+static inline bool sched_energy_enabled(void) { return false; }
+
+#endif /* CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL */
+
+#ifdef CONFIG_MEMBARRIER
+/*
+ * The scheduler provides memory barriers required by membarrier between:
+ * - prior user-space memory accesses and store to rq->membarrier_state,
+ * - store to rq->membarrier_state and following user-space memory accesses.
+ * In the same way it provides those guarantees around store to rq->curr.
+ */
+static inline void membarrier_switch_mm(struct rq *rq,
+					struct mm_struct *prev_mm,
+					struct mm_struct *next_mm)
+{
+	int membarrier_state;
+
+	if (prev_mm == next_mm)
+		return;
+
+	membarrier_state = atomic_read(&next_mm->membarrier_state);
+	if (READ_ONCE(rq->membarrier_state) == membarrier_state)
+		return;
+
+	WRITE_ONCE(rq->membarrier_state, membarrier_state);
+}
+#else
+static inline void membarrier_switch_mm(struct rq *rq,
+					struct mm_struct *prev_mm,
+					struct mm_struct *next_mm)
+{
+}
+#endif
+
+#ifdef CONFIG_SMP
+static inline bool is_per_cpu_kthread(struct task_struct *p)
+{
+	if (!(p->flags & PF_KTHREAD))
+		return false;
+
+	if (p->nr_cpus_allowed != 1)
+		return false;
+
+	return true;
+}
+#endif
+
+extern void swake_up_all_locked(struct swait_queue_head *q);
+extern void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait);
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+extern int preempt_dynamic_mode;
+extern int sched_dynamic_mode(const char *str);
+extern void sched_dynamic_update(int mode);
+#endif
+
+static inline void update_current_exec_runtime(struct task_struct *curr,
+						u64 now, u64 delta_exec)
+{
+	curr->se.sum_exec_runtime += delta_exec;
+	account_group_exec_runtime(curr, delta_exec);
+
+	curr->se.exec_start = now;
+	cgroup_account_cputime(curr, delta_exec);
+}
+
+#endif /* _KERNEL_SCHED_SCHED_H */
diff --git a/kernel/sched/smp.h b/kernel/sched/smp.h
new file mode 100644
index 000000000..2eb23dd0f
--- /dev/null
+++ b/kernel/sched/smp.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Scheduler internal SMP callback types and methods between the scheduler
+ * and other internal parts of the core kernel:
+ */
+
+extern void sched_ttwu_pending(void *arg);
+
+extern void send_call_function_single_ipi(int cpu);
+
+#ifdef CONFIG_SMP
+extern void flush_smp_call_function_queue(void);
+#else
+static inline void flush_smp_call_function_queue(void) { }
+#endif
diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
new file mode 100644
index 000000000..857f837f5
--- /dev/null
+++ b/kernel/sched/stats.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * /proc/schedstat implementation
+ */
+
+void __update_stats_wait_start(struct rq *rq, struct task_struct *p,
+			       struct sched_statistics *stats)
+{
+	u64 wait_start, prev_wait_start;
+
+	wait_start = rq_clock(rq);
+	prev_wait_start = schedstat_val(stats->wait_start);
+
+	if (p && likely(wait_start > prev_wait_start))
+		wait_start -= prev_wait_start;
+
+	__schedstat_set(stats->wait_start, wait_start);
+}
+
+void __update_stats_wait_end(struct rq *rq, struct task_struct *p,
+			     struct sched_statistics *stats)
+{
+	u64 delta = rq_clock(rq) - schedstat_val(stats->wait_start);
+
+	if (p) {
+		if (task_on_rq_migrating(p)) {
+			/*
+			 * Preserve migrating task's wait time so wait_start
+			 * time stamp can be adjusted to accumulate wait time
+			 * prior to migration.
+			 */
+			__schedstat_set(stats->wait_start, delta);
+
+			return;
+		}
+
+		trace_sched_stat_wait(p, delta);
+	}
+
+	__schedstat_set(stats->wait_max,
+			max(schedstat_val(stats->wait_max), delta));
+	__schedstat_inc(stats->wait_count);
+	__schedstat_add(stats->wait_sum, delta);
+	__schedstat_set(stats->wait_start, 0);
+}
+
+void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p,
+				    struct sched_statistics *stats)
+{
+	u64 sleep_start, block_start;
+
+	sleep_start = schedstat_val(stats->sleep_start);
+	block_start = schedstat_val(stats->block_start);
+
+	if (sleep_start) {
+		u64 delta = rq_clock(rq) - sleep_start;
+
+		if ((s64)delta < 0)
+			delta = 0;
+
+		if (unlikely(delta > schedstat_val(stats->sleep_max)))
+			__schedstat_set(stats->sleep_max, delta);
+
+		__schedstat_set(stats->sleep_start, 0);
+		__schedstat_add(stats->sum_sleep_runtime, delta);
+
+		if (p) {
+			account_scheduler_latency(p, delta >> 10, 1);
+			trace_sched_stat_sleep(p, delta);
+		}
+	}
+
+	if (block_start) {
+		u64 delta = rq_clock(rq) - block_start;
+
+		if ((s64)delta < 0)
+			delta = 0;
+
+		if (unlikely(delta > schedstat_val(stats->block_max)))
+			__schedstat_set(stats->block_max, delta);
+
+		__schedstat_set(stats->block_start, 0);
+		__schedstat_add(stats->sum_sleep_runtime, delta);
+		__schedstat_add(stats->sum_block_runtime, delta);
+
+		if (p) {
+			if (p->in_iowait) {
+				__schedstat_add(stats->iowait_sum, delta);
+				__schedstat_inc(stats->iowait_count);
+				trace_sched_stat_iowait(p, delta);
+			}
+
+			trace_sched_stat_blocked(p, delta);
+
+			/*
+			 * Blocking time is in units of nanosecs, so shift by
+			 * 20 to get a milliseconds-range estimation of the
+			 * amount of time that the task spent sleeping:
+			 */
+			if (unlikely(prof_on == SLEEP_PROFILING)) {
+				profile_hits(SLEEP_PROFILING,
+					     (void *)get_wchan(p),
+					     delta >> 20);
+			}
+			account_scheduler_latency(p, delta >> 10, 0);
+		}
+	}
+}
+
+/*
+ * Current schedstat API version.
+ *
+ * Bump this up when changing the output format or the meaning of an existing
+ * format, so that tools can adapt (or abort)
+ */
+#define SCHEDSTAT_VERSION 15
+
+static int show_schedstat(struct seq_file *seq, void *v)
+{
+	int cpu;
+
+	if (v == (void *)1) {
+		seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
+		seq_printf(seq, "timestamp %lu\n", jiffies);
+	} else {
+		struct rq *rq;
+#ifdef CONFIG_SMP
+		struct sched_domain *sd;
+		int dcount = 0;
+#endif
+		cpu = (unsigned long)(v - 2);
+		rq = cpu_rq(cpu);
+
+		/* runqueue-specific stats */
+		seq_printf(seq,
+		    "cpu%d %u 0 %u %u %u %u %llu %llu %lu",
+		    cpu, rq->yld_count,
+		    rq->sched_count, rq->sched_goidle,
+		    rq->ttwu_count, rq->ttwu_local,
+		    rq->rq_cpu_time,
+		    rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);
+
+		seq_printf(seq, "\n");
+
+#ifdef CONFIG_SMP
+		/* domain-specific stats */
+		rcu_read_lock();
+		for_each_domain(cpu, sd) {
+			enum cpu_idle_type itype;
+
+			seq_printf(seq, "domain%d %*pb", dcount++,
+				   cpumask_pr_args(sched_domain_span(sd)));
+			for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES;
+					itype++) {
+				seq_printf(seq, " %u %u %u %u %u %u %u %u",
+				    sd->lb_count[itype],
+				    sd->lb_balanced[itype],
+				    sd->lb_failed[itype],
+				    sd->lb_imbalance[itype],
+				    sd->lb_gained[itype],
+				    sd->lb_hot_gained[itype],
+				    sd->lb_nobusyq[itype],
+				    sd->lb_nobusyg[itype]);
+			}
+			seq_printf(seq,
+				   " %u %u %u %u %u %u %u %u %u %u %u %u\n",
+			    sd->alb_count, sd->alb_failed, sd->alb_pushed,
+			    sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,
+			    sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
+			    sd->ttwu_wake_remote, sd->ttwu_move_affine,
+			    sd->ttwu_move_balance);
+		}
+		rcu_read_unlock();
+#endif
+	}
+	return 0;
+}
+
+/*
+ * This iterator needs some explanation.
+ * It returns 1 for the header position.
+ * This means 2 is cpu 0.
+ * In a hotplugged system some CPUs, including cpu 0, may be missing so we have
+ * to use cpumask_* to iterate over the CPUs.
+ */
+static void *schedstat_start(struct seq_file *file, loff_t *offset)
+{
+	unsigned long n = *offset;
+
+	if (n == 0)
+		return (void *) 1;
+
+	n--;
+
+	if (n > 0)
+		n = cpumask_next(n - 1, cpu_online_mask);
+	else
+		n = cpumask_first(cpu_online_mask);
+
+	*offset = n + 1;
+
+	if (n < nr_cpu_ids)
+		return (void *)(unsigned long)(n + 2);
+
+	return NULL;
+}
+
+static void *schedstat_next(struct seq_file *file, void *data, loff_t *offset)
+{
+	(*offset)++;
+
+	return schedstat_start(file, offset);
+}
+
+static void schedstat_stop(struct seq_file *file, void *data)
+{
+}
+
+static const struct seq_operations schedstat_sops = {
+	.start = schedstat_start,
+	.next  = schedstat_next,
+	.stop  = schedstat_stop,
+	.show  = show_schedstat,
+};
+
+static int __init proc_schedstat_init(void)
+{
+	proc_create_seq("schedstat", 0, NULL, &schedstat_sops);
+	return 0;
+}
+subsys_initcall(proc_schedstat_init);
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
new file mode 100644
index 000000000..84a188913
--- /dev/null
+++ b/kernel/sched/stats.h
@@ -0,0 +1,310 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _KERNEL_STATS_H
+#define _KERNEL_STATS_H
+
+#ifdef CONFIG_SCHEDSTATS
+
+extern struct static_key_false sched_schedstats;
+
+/*
+ * Expects runqueue lock to be held for atomicity of update
+ */
+static inline void
+rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
+{
+	if (rq) {
+		rq->rq_sched_info.run_delay += delta;
+		rq->rq_sched_info.pcount++;
+	}
+}
+
+/*
+ * Expects runqueue lock to be held for atomicity of update
+ */
+static inline void
+rq_sched_info_depart(struct rq *rq, unsigned long long delta)
+{
+	if (rq)
+		rq->rq_cpu_time += delta;
+}
+
+static inline void
+rq_sched_info_dequeue(struct rq *rq, unsigned long long delta)
+{
+	if (rq)
+		rq->rq_sched_info.run_delay += delta;
+}
+#define   schedstat_enabled()		static_branch_unlikely(&sched_schedstats)
+#define __schedstat_inc(var)		do { var++; } while (0)
+#define   schedstat_inc(var)		do { if (schedstat_enabled()) { var++; } } while (0)
+#define __schedstat_add(var, amt)	do { var += (amt); } while (0)
+#define   schedstat_add(var, amt)	do { if (schedstat_enabled()) { var += (amt); } } while (0)
+#define __schedstat_set(var, val)	do { var = (val); } while (0)
+#define   schedstat_set(var, val)	do { if (schedstat_enabled()) { var = (val); } } while (0)
+#define   schedstat_val(var)		(var)
+#define   schedstat_val_or_zero(var)	((schedstat_enabled()) ? (var) : 0)
+
+void __update_stats_wait_start(struct rq *rq, struct task_struct *p,
+			       struct sched_statistics *stats);
+
+void __update_stats_wait_end(struct rq *rq, struct task_struct *p,
+			     struct sched_statistics *stats);
+void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p,
+				    struct sched_statistics *stats);
+
+static inline void
+check_schedstat_required(void)
+{
+	if (schedstat_enabled())
+		return;
+
+	/* Force schedstat enabled if a dependent tracepoint is active */
+	if (trace_sched_stat_wait_enabled()    ||
+	    trace_sched_stat_sleep_enabled()   ||
+	    trace_sched_stat_iowait_enabled()  ||
+	    trace_sched_stat_blocked_enabled() ||
+	    trace_sched_stat_runtime_enabled())
+		printk_deferred_once("Scheduler tracepoints stat_sleep, stat_iowait, stat_blocked and stat_runtime require the kernel parameter schedstats=enable or kernel.sched_schedstats=1\n");
+}
+
+#else /* !CONFIG_SCHEDSTATS: */
+
+static inline void rq_sched_info_arrive  (struct rq *rq, unsigned long long delta) { }
+static inline void rq_sched_info_dequeue(struct rq *rq, unsigned long long delta) { }
+static inline void rq_sched_info_depart  (struct rq *rq, unsigned long long delta) { }
+# define   schedstat_enabled()		0
+# define __schedstat_inc(var)		do { } while (0)
+# define   schedstat_inc(var)		do { } while (0)
+# define __schedstat_add(var, amt)	do { } while (0)
+# define   schedstat_add(var, amt)	do { } while (0)
+# define __schedstat_set(var, val)	do { } while (0)
+# define   schedstat_set(var, val)	do { } while (0)
+# define   schedstat_val(var)		0
+# define   schedstat_val_or_zero(var)	0
+
+# define __update_stats_wait_start(rq, p, stats)       do { } while (0)
+# define __update_stats_wait_end(rq, p, stats)         do { } while (0)
+# define __update_stats_enqueue_sleeper(rq, p, stats)  do { } while (0)
+# define check_schedstat_required()                    do { } while (0)
+
+#endif /* CONFIG_SCHEDSTATS */
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+struct sched_entity_stats {
+	struct sched_entity     se;
+	struct sched_statistics stats;
+} __no_randomize_layout;
+#endif
+
+static inline struct sched_statistics *
+__schedstats_from_se(struct sched_entity *se)
+{
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	if (!entity_is_task(se))
+		return &container_of(se, struct sched_entity_stats, se)->stats;
+#endif
+	return &task_of(se)->stats;
+}
+
+#ifdef CONFIG_PSI
+void psi_task_change(struct task_struct *task, int clear, int set);
+void psi_task_switch(struct task_struct *prev, struct task_struct *next,
+		     bool sleep);
+void psi_account_irqtime(struct task_struct *task, u32 delta);
+
+/*
+ * PSI tracks state that persists across sleeps, such as iowaits and
+ * memory stalls. As a result, it has to distinguish between sleeps,
+ * where a task's runnable state changes, and requeues, where a task
+ * and its state are being moved between CPUs and runqueues.
+ */
+static inline void psi_enqueue(struct task_struct *p, bool wakeup)
+{
+	int clear = 0, set = TSK_RUNNING;
+
+	if (static_branch_likely(&psi_disabled))
+		return;
+
+	if (p->in_memstall)
+		set |= TSK_MEMSTALL_RUNNING;
+
+	if (!wakeup || p->sched_psi_wake_requeue) {
+		if (p->in_memstall)
+			set |= TSK_MEMSTALL;
+		if (p->sched_psi_wake_requeue)
+			p->sched_psi_wake_requeue = 0;
+	} else {
+		if (p->in_iowait)
+			clear |= TSK_IOWAIT;
+	}
+
+	psi_task_change(p, clear, set);
+}
+
+static inline void psi_dequeue(struct task_struct *p, bool sleep)
+{
+	int clear = TSK_RUNNING;
+
+	if (static_branch_likely(&psi_disabled))
+		return;
+
+	/*
+	 * A voluntary sleep is a dequeue followed by a task switch. To
+	 * avoid walking all ancestors twice, psi_task_switch() handles
+	 * TSK_RUNNING and TSK_IOWAIT for us when it moves TSK_ONCPU.
+	 * Do nothing here.
+	 */
+	if (sleep)
+		return;
+
+	if (p->in_memstall)
+		clear |= (TSK_MEMSTALL | TSK_MEMSTALL_RUNNING);
+
+	psi_task_change(p, clear, 0);
+}
+
+static inline void psi_ttwu_dequeue(struct task_struct *p)
+{
+	if (static_branch_likely(&psi_disabled))
+		return;
+	/*
+	 * Is the task being migrated during a wakeup? Make sure to
+	 * deregister its sleep-persistent psi states from the old
+	 * queue, and let psi_enqueue() know it has to requeue.
+	 */
+	if (unlikely(p->in_iowait || p->in_memstall)) {
+		struct rq_flags rf;
+		struct rq *rq;
+		int clear = 0;
+
+		if (p->in_iowait)
+			clear |= TSK_IOWAIT;
+		if (p->in_memstall)
+			clear |= TSK_MEMSTALL;
+
+		rq = __task_rq_lock(p, &rf);
+		psi_task_change(p, clear, 0);
+		p->sched_psi_wake_requeue = 1;
+		__task_rq_unlock(rq, &rf);
+	}
+}
+
+static inline void psi_sched_switch(struct task_struct *prev,
+				    struct task_struct *next,
+				    bool sleep)
+{
+	if (static_branch_likely(&psi_disabled))
+		return;
+
+	psi_task_switch(prev, next, sleep);
+}
+
+#else /* CONFIG_PSI */
+static inline void psi_enqueue(struct task_struct *p, bool wakeup) {}
+static inline void psi_dequeue(struct task_struct *p, bool sleep) {}
+static inline void psi_ttwu_dequeue(struct task_struct *p) {}
+static inline void psi_sched_switch(struct task_struct *prev,
+				    struct task_struct *next,
+				    bool sleep) {}
+static inline void psi_account_irqtime(struct task_struct *task, u32 delta) {}
+#endif /* CONFIG_PSI */
+
+#ifdef CONFIG_SCHED_INFO
+/*
+ * We are interested in knowing how long it was from the *first* time a
+ * task was queued to the time that it finally hit a CPU, we call this routine
+ * from dequeue_task() to account for possible rq->clock skew across CPUs. The
+ * delta taken on each CPU would annul the skew.
+ */
+static inline void sched_info_dequeue(struct rq *rq, struct task_struct *t)
+{
+	unsigned long long delta = 0;
+
+	if (!t->sched_info.last_queued)
+		return;
+
+	delta = rq_clock(rq) - t->sched_info.last_queued;
+	t->sched_info.last_queued = 0;
+	t->sched_info.run_delay += delta;
+
+	rq_sched_info_dequeue(rq, delta);
+}
+
+/*
+ * Called when a task finally hits the CPU.  We can now calculate how
+ * long it was waiting to run.  We also note when it began so that we
+ * can keep stats on how long its timeslice is.
+ */
+static void sched_info_arrive(struct rq *rq, struct task_struct *t)
+{
+	unsigned long long now, delta = 0;
+
+	if (!t->sched_info.last_queued)
+		return;
+
+	now = rq_clock(rq);
+	delta = now - t->sched_info.last_queued;
+	t->sched_info.last_queued = 0;
+	t->sched_info.run_delay += delta;
+	t->sched_info.last_arrival = now;
+	t->sched_info.pcount++;
+
+	rq_sched_info_arrive(rq, delta);
+}
+
+/*
+ * This function is only called from enqueue_task(), but also only updates
+ * the timestamp if it is already not set.  It's assumed that
+ * sched_info_dequeue() will clear that stamp when appropriate.
+ */
+static inline void sched_info_enqueue(struct rq *rq, struct task_struct *t)
+{
+	if (!t->sched_info.last_queued)
+		t->sched_info.last_queued = rq_clock(rq);
+}
+
+/*
+ * Called when a process ceases being the active-running process involuntarily
+ * due, typically, to expiring its time slice (this may also be called when
+ * switching to the idle task).  Now we can calculate how long we ran.
+ * Also, if the process is still in the TASK_RUNNING state, call
+ * sched_info_enqueue() to mark that it has now again started waiting on
+ * the runqueue.
+ */
+static inline void sched_info_depart(struct rq *rq, struct task_struct *t)
+{
+	unsigned long long delta = rq_clock(rq) - t->sched_info.last_arrival;
+
+	rq_sched_info_depart(rq, delta);
+
+	if (task_is_running(t))
+		sched_info_enqueue(rq, t);
+}
+
+/*
+ * Called when tasks are switched involuntarily due, typically, to expiring
+ * their time slice.  (This may also be called when switching to or from
+ * the idle task.)  We are only called when prev != next.
+ */
+static inline void
+sched_info_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next)
+{
+	/*
+	 * prev now departs the CPU.  It's not interesting to record
+	 * stats about how efficient we were at scheduling the idle
+	 * process, however.
+	 */
+	if (prev != rq->idle)
+		sched_info_depart(rq, prev);
+
+	if (next != rq->idle)
+		sched_info_arrive(rq, next);
+}
+
+#else /* !CONFIG_SCHED_INFO: */
+# define sched_info_enqueue(rq, t)	do { } while (0)
+# define sched_info_dequeue(rq, t)	do { } while (0)
+# define sched_info_switch(rq, t, next)	do { } while (0)
+#endif /* CONFIG_SCHED_INFO */
+
+#endif /* _KERNEL_STATS_H */
diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c
new file mode 100644
index 000000000..85590599b
--- /dev/null
+++ b/kernel/sched/stop_task.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * stop-task scheduling class.
+ *
+ * The stop task is the highest priority task in the system, it preempts
+ * everything and will be preempted by nothing.
+ *
+ * See kernel/stop_machine.c
+ */
+
+#ifdef CONFIG_SMP
+static int
+select_task_rq_stop(struct task_struct *p, int cpu, int flags)
+{
+	return task_cpu(p); /* stop tasks as never migrate */
+}
+
+static int
+balance_stop(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+{
+	return sched_stop_runnable(rq);
+}
+#endif /* CONFIG_SMP */
+
+static void
+check_preempt_curr_stop(struct rq *rq, struct task_struct *p, int flags)
+{
+	/* we're never preempted */
+}
+
+static void set_next_task_stop(struct rq *rq, struct task_struct *stop, bool first)
+{
+	stop->se.exec_start = rq_clock_task(rq);
+}
+
+static struct task_struct *pick_task_stop(struct rq *rq)
+{
+	if (!sched_stop_runnable(rq))
+		return NULL;
+
+	return rq->stop;
+}
+
+static struct task_struct *pick_next_task_stop(struct rq *rq)
+{
+	struct task_struct *p = pick_task_stop(rq);
+
+	if (p)
+		set_next_task_stop(rq, p, true);
+
+	return p;
+}
+
+static void
+enqueue_task_stop(struct rq *rq, struct task_struct *p, int flags)
+{
+	add_nr_running(rq, 1);
+}
+
+static void
+dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags)
+{
+	sub_nr_running(rq, 1);
+}
+
+static void yield_task_stop(struct rq *rq)
+{
+	BUG(); /* the stop task should never yield, its pointless. */
+}
+
+static void put_prev_task_stop(struct rq *rq, struct task_struct *prev)
+{
+	struct task_struct *curr = rq->curr;
+	u64 now, delta_exec;
+
+	now = rq_clock_task(rq);
+	delta_exec = now - curr->se.exec_start;
+	if (unlikely((s64)delta_exec < 0))
+		delta_exec = 0;
+
+	schedstat_set(curr->stats.exec_max,
+		      max(curr->stats.exec_max, delta_exec));
+
+	update_current_exec_runtime(curr, now, delta_exec);
+}
+
+/*
+ * scheduler tick hitting a task of our scheduling class.
+ *
+ * NOTE: This function can be called remotely by the tick offload that
+ * goes along full dynticks. Therefore no local assumption can be made
+ * and everything must be accessed through the @rq and @curr passed in
+ * parameters.
+ */
+static void task_tick_stop(struct rq *rq, struct task_struct *curr, int queued)
+{
+}
+
+static void switched_to_stop(struct rq *rq, struct task_struct *p)
+{
+	BUG(); /* its impossible to change to this class */
+}
+
+static void
+prio_changed_stop(struct rq *rq, struct task_struct *p, int oldprio)
+{
+	BUG(); /* how!?, what priority? */
+}
+
+static void update_curr_stop(struct rq *rq)
+{
+}
+
+/*
+ * Simple, special scheduling class for the per-CPU stop tasks:
+ */
+DEFINE_SCHED_CLASS(stop) = {
+
+	.enqueue_task		= enqueue_task_stop,
+	.dequeue_task		= dequeue_task_stop,
+	.yield_task		= yield_task_stop,
+
+	.check_preempt_curr	= check_preempt_curr_stop,
+
+	.pick_next_task		= pick_next_task_stop,
+	.put_prev_task		= put_prev_task_stop,
+	.set_next_task          = set_next_task_stop,
+
+#ifdef CONFIG_SMP
+	.balance		= balance_stop,
+	.pick_task		= pick_task_stop,
+	.select_task_rq		= select_task_rq_stop,
+	.set_cpus_allowed	= set_cpus_allowed_common,
+#endif
+
+	.task_tick		= task_tick_stop,
+
+	.prio_changed		= prio_changed_stop,
+	.switched_to		= switched_to_stop,
+	.update_curr		= update_curr_stop,
+};
diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c
new file mode 100644
index 000000000..76b9b796e
--- /dev/null
+++ b/kernel/sched/swait.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * <linux/swait.h> (simple wait queues ) implementation:
+ */
+
+void __init_swait_queue_head(struct swait_queue_head *q, const char *name,
+			     struct lock_class_key *key)
+{
+	raw_spin_lock_init(&q->lock);
+	lockdep_set_class_and_name(&q->lock, key, name);
+	INIT_LIST_HEAD(&q->task_list);
+}
+EXPORT_SYMBOL(__init_swait_queue_head);
+
+/*
+ * The thing about the wake_up_state() return value; I think we can ignore it.
+ *
+ * If for some reason it would return 0, that means the previously waiting
+ * task is already running, so it will observe condition true (or has already).
+ */
+void swake_up_locked(struct swait_queue_head *q)
+{
+	struct swait_queue *curr;
+
+	if (list_empty(&q->task_list))
+		return;
+
+	curr = list_first_entry(&q->task_list, typeof(*curr), task_list);
+	wake_up_process(curr->task);
+	list_del_init(&curr->task_list);
+}
+EXPORT_SYMBOL(swake_up_locked);
+
+/*
+ * Wake up all waiters. This is an interface which is solely exposed for
+ * completions and not for general usage.
+ *
+ * It is intentionally different from swake_up_all() to allow usage from
+ * hard interrupt context and interrupt disabled regions.
+ */
+void swake_up_all_locked(struct swait_queue_head *q)
+{
+	while (!list_empty(&q->task_list))
+		swake_up_locked(q);
+}
+
+void swake_up_one(struct swait_queue_head *q)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&q->lock, flags);
+	swake_up_locked(q);
+	raw_spin_unlock_irqrestore(&q->lock, flags);
+}
+EXPORT_SYMBOL(swake_up_one);
+
+/*
+ * Does not allow usage from IRQ disabled, since we must be able to
+ * release IRQs to guarantee bounded hold time.
+ */
+void swake_up_all(struct swait_queue_head *q)
+{
+	struct swait_queue *curr;
+	LIST_HEAD(tmp);
+
+	raw_spin_lock_irq(&q->lock);
+	list_splice_init(&q->task_list, &tmp);
+	while (!list_empty(&tmp)) {
+		curr = list_first_entry(&tmp, typeof(*curr), task_list);
+
+		wake_up_state(curr->task, TASK_NORMAL);
+		list_del_init(&curr->task_list);
+
+		if (list_empty(&tmp))
+			break;
+
+		raw_spin_unlock_irq(&q->lock);
+		raw_spin_lock_irq(&q->lock);
+	}
+	raw_spin_unlock_irq(&q->lock);
+}
+EXPORT_SYMBOL(swake_up_all);
+
+void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait)
+{
+	wait->task = current;
+	if (list_empty(&wait->task_list))
+		list_add_tail(&wait->task_list, &q->task_list);
+}
+
+void prepare_to_swait_exclusive(struct swait_queue_head *q, struct swait_queue *wait, int state)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&q->lock, flags);
+	__prepare_to_swait(q, wait);
+	set_current_state(state);
+	raw_spin_unlock_irqrestore(&q->lock, flags);
+}
+EXPORT_SYMBOL(prepare_to_swait_exclusive);
+
+long prepare_to_swait_event(struct swait_queue_head *q, struct swait_queue *wait, int state)
+{
+	unsigned long flags;
+	long ret = 0;
+
+	raw_spin_lock_irqsave(&q->lock, flags);
+	if (signal_pending_state(state, current)) {
+		/*
+		 * See prepare_to_wait_event(). TL;DR, subsequent swake_up_one()
+		 * must not see us.
+		 */
+		list_del_init(&wait->task_list);
+		ret = -ERESTARTSYS;
+	} else {
+		__prepare_to_swait(q, wait);
+		set_current_state(state);
+	}
+	raw_spin_unlock_irqrestore(&q->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(prepare_to_swait_event);
+
+void __finish_swait(struct swait_queue_head *q, struct swait_queue *wait)
+{
+	__set_current_state(TASK_RUNNING);
+	if (!list_empty(&wait->task_list))
+		list_del_init(&wait->task_list);
+}
+
+void finish_swait(struct swait_queue_head *q, struct swait_queue *wait)
+{
+	unsigned long flags;
+
+	__set_current_state(TASK_RUNNING);
+
+	if (!list_empty_careful(&wait->task_list)) {
+		raw_spin_lock_irqsave(&q->lock, flags);
+		list_del_init(&wait->task_list);
+		raw_spin_unlock_irqrestore(&q->lock, flags);
+	}
+}
+EXPORT_SYMBOL(finish_swait);
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
new file mode 100644
index 000000000..8739c2a5a
--- /dev/null
+++ b/kernel/sched/topology.c
@@ -0,0 +1,2647 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Scheduler topology setup/handling methods
+ */
+
+DEFINE_MUTEX(sched_domains_mutex);
+
+/* Protected by sched_domains_mutex: */
+static cpumask_var_t sched_domains_tmpmask;
+static cpumask_var_t sched_domains_tmpmask2;
+
+#ifdef CONFIG_SCHED_DEBUG
+
+static int __init sched_debug_setup(char *str)
+{
+	sched_debug_verbose = true;
+
+	return 0;
+}
+early_param("sched_verbose", sched_debug_setup);
+
+static inline bool sched_debug(void)
+{
+	return sched_debug_verbose;
+}
+
+#define SD_FLAG(_name, mflags) [__##_name] = { .meta_flags = mflags, .name = #_name },
+const struct sd_flag_debug sd_flag_debug[] = {
+#include <linux/sched/sd_flags.h>
+};
+#undef SD_FLAG
+
+static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
+				  struct cpumask *groupmask)
+{
+	struct sched_group *group = sd->groups;
+	unsigned long flags = sd->flags;
+	unsigned int idx;
+
+	cpumask_clear(groupmask);
+
+	printk(KERN_DEBUG "%*s domain-%d: ", level, "", level);
+	printk(KERN_CONT "span=%*pbl level=%s\n",
+	       cpumask_pr_args(sched_domain_span(sd)), sd->name);
+
+	if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
+		printk(KERN_ERR "ERROR: domain->span does not contain CPU%d\n", cpu);
+	}
+	if (group && !cpumask_test_cpu(cpu, sched_group_span(group))) {
+		printk(KERN_ERR "ERROR: domain->groups does not contain CPU%d\n", cpu);
+	}
+
+	for_each_set_bit(idx, &flags, __SD_FLAG_CNT) {
+		unsigned int flag = BIT(idx);
+		unsigned int meta_flags = sd_flag_debug[idx].meta_flags;
+
+		if ((meta_flags & SDF_SHARED_CHILD) && sd->child &&
+		    !(sd->child->flags & flag))
+			printk(KERN_ERR "ERROR: flag %s set here but not in child\n",
+			       sd_flag_debug[idx].name);
+
+		if ((meta_flags & SDF_SHARED_PARENT) && sd->parent &&
+		    !(sd->parent->flags & flag))
+			printk(KERN_ERR "ERROR: flag %s set here but not in parent\n",
+			       sd_flag_debug[idx].name);
+	}
+
+	printk(KERN_DEBUG "%*s groups:", level + 1, "");
+	do {
+		if (!group) {
+			printk("\n");
+			printk(KERN_ERR "ERROR: group is NULL\n");
+			break;
+		}
+
+		if (cpumask_empty(sched_group_span(group))) {
+			printk(KERN_CONT "\n");
+			printk(KERN_ERR "ERROR: empty group\n");
+			break;
+		}
+
+		if (!(sd->flags & SD_OVERLAP) &&
+		    cpumask_intersects(groupmask, sched_group_span(group))) {
+			printk(KERN_CONT "\n");
+			printk(KERN_ERR "ERROR: repeated CPUs\n");
+			break;
+		}
+
+		cpumask_or(groupmask, groupmask, sched_group_span(group));
+
+		printk(KERN_CONT " %d:{ span=%*pbl",
+				group->sgc->id,
+				cpumask_pr_args(sched_group_span(group)));
+
+		if ((sd->flags & SD_OVERLAP) &&
+		    !cpumask_equal(group_balance_mask(group), sched_group_span(group))) {
+			printk(KERN_CONT " mask=%*pbl",
+				cpumask_pr_args(group_balance_mask(group)));
+		}
+
+		if (group->sgc->capacity != SCHED_CAPACITY_SCALE)
+			printk(KERN_CONT " cap=%lu", group->sgc->capacity);
+
+		if (group == sd->groups && sd->child &&
+		    !cpumask_equal(sched_domain_span(sd->child),
+				   sched_group_span(group))) {
+			printk(KERN_ERR "ERROR: domain->groups does not match domain->child\n");
+		}
+
+		printk(KERN_CONT " }");
+
+		group = group->next;
+
+		if (group != sd->groups)
+			printk(KERN_CONT ",");
+
+	} while (group != sd->groups);
+	printk(KERN_CONT "\n");
+
+	if (!cpumask_equal(sched_domain_span(sd), groupmask))
+		printk(KERN_ERR "ERROR: groups don't span domain->span\n");
+
+	if (sd->parent &&
+	    !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
+		printk(KERN_ERR "ERROR: parent span is not a superset of domain->span\n");
+	return 0;
+}
+
+static void sched_domain_debug(struct sched_domain *sd, int cpu)
+{
+	int level = 0;
+
+	if (!sched_debug_verbose)
+		return;
+
+	if (!sd) {
+		printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
+		return;
+	}
+
+	printk(KERN_DEBUG "CPU%d attaching sched-domain(s):\n", cpu);
+
+	for (;;) {
+		if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
+			break;
+		level++;
+		sd = sd->parent;
+		if (!sd)
+			break;
+	}
+}
+#else /* !CONFIG_SCHED_DEBUG */
+
+# define sched_debug_verbose 0
+# define sched_domain_debug(sd, cpu) do { } while (0)
+static inline bool sched_debug(void)
+{
+	return false;
+}
+#endif /* CONFIG_SCHED_DEBUG */
+
+/* Generate a mask of SD flags with the SDF_NEEDS_GROUPS metaflag */
+#define SD_FLAG(name, mflags) (name * !!((mflags) & SDF_NEEDS_GROUPS)) |
+static const unsigned int SD_DEGENERATE_GROUPS_MASK =
+#include <linux/sched/sd_flags.h>
+0;
+#undef SD_FLAG
+
+static int sd_degenerate(struct sched_domain *sd)
+{
+	if (cpumask_weight(sched_domain_span(sd)) == 1)
+		return 1;
+
+	/* Following flags need at least 2 groups */
+	if ((sd->flags & SD_DEGENERATE_GROUPS_MASK) &&
+	    (sd->groups != sd->groups->next))
+		return 0;
+
+	/* Following flags don't use groups */
+	if (sd->flags & (SD_WAKE_AFFINE))
+		return 0;
+
+	return 1;
+}
+
+static int
+sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
+{
+	unsigned long cflags = sd->flags, pflags = parent->flags;
+
+	if (sd_degenerate(parent))
+		return 1;
+
+	if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
+		return 0;
+
+	/* Flags needing groups don't count if only 1 group in parent */
+	if (parent->groups == parent->groups->next)
+		pflags &= ~SD_DEGENERATE_GROUPS_MASK;
+
+	if (~cflags & pflags)
+		return 0;
+
+	return 1;
+}
+
+#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
+DEFINE_STATIC_KEY_FALSE(sched_energy_present);
+static unsigned int sysctl_sched_energy_aware = 1;
+DEFINE_MUTEX(sched_energy_mutex);
+bool sched_energy_update;
+
+void rebuild_sched_domains_energy(void)
+{
+	mutex_lock(&sched_energy_mutex);
+	sched_energy_update = true;
+	rebuild_sched_domains();
+	sched_energy_update = false;
+	mutex_unlock(&sched_energy_mutex);
+}
+
+#ifdef CONFIG_PROC_SYSCTL
+static int sched_energy_aware_handler(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int ret, state;
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+	if (!ret && write) {
+		state = static_branch_unlikely(&sched_energy_present);
+		if (state != sysctl_sched_energy_aware)
+			rebuild_sched_domains_energy();
+	}
+
+	return ret;
+}
+
+static struct ctl_table sched_energy_aware_sysctls[] = {
+	{
+		.procname       = "sched_energy_aware",
+		.data           = &sysctl_sched_energy_aware,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = sched_energy_aware_handler,
+		.extra1         = SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE,
+	},
+	{}
+};
+
+static int __init sched_energy_aware_sysctl_init(void)
+{
+	register_sysctl_init("kernel", sched_energy_aware_sysctls);
+	return 0;
+}
+
+late_initcall(sched_energy_aware_sysctl_init);
+#endif
+
+static void free_pd(struct perf_domain *pd)
+{
+	struct perf_domain *tmp;
+
+	while (pd) {
+		tmp = pd->next;
+		kfree(pd);
+		pd = tmp;
+	}
+}
+
+static struct perf_domain *find_pd(struct perf_domain *pd, int cpu)
+{
+	while (pd) {
+		if (cpumask_test_cpu(cpu, perf_domain_span(pd)))
+			return pd;
+		pd = pd->next;
+	}
+
+	return NULL;
+}
+
+static struct perf_domain *pd_init(int cpu)
+{
+	struct em_perf_domain *obj = em_cpu_get(cpu);
+	struct perf_domain *pd;
+
+	if (!obj) {
+		if (sched_debug())
+			pr_info("%s: no EM found for CPU%d\n", __func__, cpu);
+		return NULL;
+	}
+
+	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
+	if (!pd)
+		return NULL;
+	pd->em_pd = obj;
+
+	return pd;
+}
+
+static void perf_domain_debug(const struct cpumask *cpu_map,
+						struct perf_domain *pd)
+{
+	if (!sched_debug() || !pd)
+		return;
+
+	printk(KERN_DEBUG "root_domain %*pbl:", cpumask_pr_args(cpu_map));
+
+	while (pd) {
+		printk(KERN_CONT " pd%d:{ cpus=%*pbl nr_pstate=%d }",
+				cpumask_first(perf_domain_span(pd)),
+				cpumask_pr_args(perf_domain_span(pd)),
+				em_pd_nr_perf_states(pd->em_pd));
+		pd = pd->next;
+	}
+
+	printk(KERN_CONT "\n");
+}
+
+static void destroy_perf_domain_rcu(struct rcu_head *rp)
+{
+	struct perf_domain *pd;
+
+	pd = container_of(rp, struct perf_domain, rcu);
+	free_pd(pd);
+}
+
+static void sched_energy_set(bool has_eas)
+{
+	if (!has_eas && static_branch_unlikely(&sched_energy_present)) {
+		if (sched_debug())
+			pr_info("%s: stopping EAS\n", __func__);
+		static_branch_disable_cpuslocked(&sched_energy_present);
+	} else if (has_eas && !static_branch_unlikely(&sched_energy_present)) {
+		if (sched_debug())
+			pr_info("%s: starting EAS\n", __func__);
+		static_branch_enable_cpuslocked(&sched_energy_present);
+	}
+}
+
+/*
+ * EAS can be used on a root domain if it meets all the following conditions:
+ *    1. an Energy Model (EM) is available;
+ *    2. the SD_ASYM_CPUCAPACITY flag is set in the sched_domain hierarchy.
+ *    3. no SMT is detected.
+ *    4. the EM complexity is low enough to keep scheduling overheads low;
+ *    5. schedutil is driving the frequency of all CPUs of the rd;
+ *    6. frequency invariance support is present;
+ *
+ * The complexity of the Energy Model is defined as:
+ *
+ *              C = nr_pd * (nr_cpus + nr_ps)
+ *
+ * with parameters defined as:
+ *  - nr_pd:    the number of performance domains
+ *  - nr_cpus:  the number of CPUs
+ *  - nr_ps:    the sum of the number of performance states of all performance
+ *              domains (for example, on a system with 2 performance domains,
+ *              with 10 performance states each, nr_ps = 2 * 10 = 20).
+ *
+ * It is generally not a good idea to use such a model in the wake-up path on
+ * very complex platforms because of the associated scheduling overheads. The
+ * arbitrary constraint below prevents that. It makes EAS usable up to 16 CPUs
+ * with per-CPU DVFS and less than 8 performance states each, for example.
+ */
+#define EM_MAX_COMPLEXITY 2048
+
+extern struct cpufreq_governor schedutil_gov;
+static bool build_perf_domains(const struct cpumask *cpu_map)
+{
+	int i, nr_pd = 0, nr_ps = 0, nr_cpus = cpumask_weight(cpu_map);
+	struct perf_domain *pd = NULL, *tmp;
+	int cpu = cpumask_first(cpu_map);
+	struct root_domain *rd = cpu_rq(cpu)->rd;
+	struct cpufreq_policy *policy;
+	struct cpufreq_governor *gov;
+
+	if (!sysctl_sched_energy_aware)
+		goto free;
+
+	/* EAS is enabled for asymmetric CPU capacity topologies. */
+	if (!per_cpu(sd_asym_cpucapacity, cpu)) {
+		if (sched_debug()) {
+			pr_info("rd %*pbl: CPUs do not have asymmetric capacities\n",
+					cpumask_pr_args(cpu_map));
+		}
+		goto free;
+	}
+
+	/* EAS definitely does *not* handle SMT */
+	if (sched_smt_active()) {
+		pr_warn("rd %*pbl: Disabling EAS, SMT is not supported\n",
+			cpumask_pr_args(cpu_map));
+		goto free;
+	}
+
+	if (!arch_scale_freq_invariant()) {
+		if (sched_debug()) {
+			pr_warn("rd %*pbl: Disabling EAS: frequency-invariant load tracking not yet supported",
+				cpumask_pr_args(cpu_map));
+		}
+		goto free;
+	}
+
+	for_each_cpu(i, cpu_map) {
+		/* Skip already covered CPUs. */
+		if (find_pd(pd, i))
+			continue;
+
+		/* Do not attempt EAS if schedutil is not being used. */
+		policy = cpufreq_cpu_get(i);
+		if (!policy)
+			goto free;
+		gov = policy->governor;
+		cpufreq_cpu_put(policy);
+		if (gov != &schedutil_gov) {
+			if (rd->pd)
+				pr_warn("rd %*pbl: Disabling EAS, schedutil is mandatory\n",
+						cpumask_pr_args(cpu_map));
+			goto free;
+		}
+
+		/* Create the new pd and add it to the local list. */
+		tmp = pd_init(i);
+		if (!tmp)
+			goto free;
+		tmp->next = pd;
+		pd = tmp;
+
+		/*
+		 * Count performance domains and performance states for the
+		 * complexity check.
+		 */
+		nr_pd++;
+		nr_ps += em_pd_nr_perf_states(pd->em_pd);
+	}
+
+	/* Bail out if the Energy Model complexity is too high. */
+	if (nr_pd * (nr_ps + nr_cpus) > EM_MAX_COMPLEXITY) {
+		WARN(1, "rd %*pbl: Failed to start EAS, EM complexity is too high\n",
+						cpumask_pr_args(cpu_map));
+		goto free;
+	}
+
+	perf_domain_debug(cpu_map, pd);
+
+	/* Attach the new list of performance domains to the root domain. */
+	tmp = rd->pd;
+	rcu_assign_pointer(rd->pd, pd);
+	if (tmp)
+		call_rcu(&tmp->rcu, destroy_perf_domain_rcu);
+
+	return !!pd;
+
+free:
+	free_pd(pd);
+	tmp = rd->pd;
+	rcu_assign_pointer(rd->pd, NULL);
+	if (tmp)
+		call_rcu(&tmp->rcu, destroy_perf_domain_rcu);
+
+	return false;
+}
+#else
+static void free_pd(struct perf_domain *pd) { }
+#endif /* CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL*/
+
+static void free_rootdomain(struct rcu_head *rcu)
+{
+	struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
+
+	cpupri_cleanup(&rd->cpupri);
+	cpudl_cleanup(&rd->cpudl);
+	free_cpumask_var(rd->dlo_mask);
+	free_cpumask_var(rd->rto_mask);
+	free_cpumask_var(rd->online);
+	free_cpumask_var(rd->span);
+	free_pd(rd->pd);
+	kfree(rd);
+}
+
+void rq_attach_root(struct rq *rq, struct root_domain *rd)
+{
+	struct root_domain *old_rd = NULL;
+	unsigned long flags;
+
+	raw_spin_rq_lock_irqsave(rq, flags);
+
+	if (rq->rd) {
+		old_rd = rq->rd;
+
+		if (cpumask_test_cpu(rq->cpu, old_rd->online))
+			set_rq_offline(rq);
+
+		cpumask_clear_cpu(rq->cpu, old_rd->span);
+
+		/*
+		 * If we dont want to free the old_rd yet then
+		 * set old_rd to NULL to skip the freeing later
+		 * in this function:
+		 */
+		if (!atomic_dec_and_test(&old_rd->refcount))
+			old_rd = NULL;
+	}
+
+	atomic_inc(&rd->refcount);
+	rq->rd = rd;
+
+	cpumask_set_cpu(rq->cpu, rd->span);
+	if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
+		set_rq_online(rq);
+
+	raw_spin_rq_unlock_irqrestore(rq, flags);
+
+	if (old_rd)
+		call_rcu(&old_rd->rcu, free_rootdomain);
+}
+
+void sched_get_rd(struct root_domain *rd)
+{
+	atomic_inc(&rd->refcount);
+}
+
+void sched_put_rd(struct root_domain *rd)
+{
+	if (!atomic_dec_and_test(&rd->refcount))
+		return;
+
+	call_rcu(&rd->rcu, free_rootdomain);
+}
+
+static int init_rootdomain(struct root_domain *rd)
+{
+	if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL))
+		goto out;
+	if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL))
+		goto free_span;
+	if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL))
+		goto free_online;
+	if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
+		goto free_dlo_mask;
+
+#ifdef HAVE_RT_PUSH_IPI
+	rd->rto_cpu = -1;
+	raw_spin_lock_init(&rd->rto_lock);
+	rd->rto_push_work = IRQ_WORK_INIT_HARD(rto_push_irq_work_func);
+#endif
+
+	rd->visit_gen = 0;
+	init_dl_bw(&rd->dl_bw);
+	if (cpudl_init(&rd->cpudl) != 0)
+		goto free_rto_mask;
+
+	if (cpupri_init(&rd->cpupri) != 0)
+		goto free_cpudl;
+	return 0;
+
+free_cpudl:
+	cpudl_cleanup(&rd->cpudl);
+free_rto_mask:
+	free_cpumask_var(rd->rto_mask);
+free_dlo_mask:
+	free_cpumask_var(rd->dlo_mask);
+free_online:
+	free_cpumask_var(rd->online);
+free_span:
+	free_cpumask_var(rd->span);
+out:
+	return -ENOMEM;
+}
+
+/*
+ * By default the system creates a single root-domain with all CPUs as
+ * members (mimicking the global state we have today).
+ */
+struct root_domain def_root_domain;
+
+void init_defrootdomain(void)
+{
+	init_rootdomain(&def_root_domain);
+
+	atomic_set(&def_root_domain.refcount, 1);
+}
+
+static struct root_domain *alloc_rootdomain(void)
+{
+	struct root_domain *rd;
+
+	rd = kzalloc(sizeof(*rd), GFP_KERNEL);
+	if (!rd)
+		return NULL;
+
+	if (init_rootdomain(rd) != 0) {
+		kfree(rd);
+		return NULL;
+	}
+
+	return rd;
+}
+
+static void free_sched_groups(struct sched_group *sg, int free_sgc)
+{
+	struct sched_group *tmp, *first;
+
+	if (!sg)
+		return;
+
+	first = sg;
+	do {
+		tmp = sg->next;
+
+		if (free_sgc && atomic_dec_and_test(&sg->sgc->ref))
+			kfree(sg->sgc);
+
+		if (atomic_dec_and_test(&sg->ref))
+			kfree(sg);
+		sg = tmp;
+	} while (sg != first);
+}
+
+static void destroy_sched_domain(struct sched_domain *sd)
+{
+	/*
+	 * A normal sched domain may have multiple group references, an
+	 * overlapping domain, having private groups, only one.  Iterate,
+	 * dropping group/capacity references, freeing where none remain.
+	 */
+	free_sched_groups(sd->groups, 1);
+
+	if (sd->shared && atomic_dec_and_test(&sd->shared->ref))
+		kfree(sd->shared);
+	kfree(sd);
+}
+
+static void destroy_sched_domains_rcu(struct rcu_head *rcu)
+{
+	struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
+
+	while (sd) {
+		struct sched_domain *parent = sd->parent;
+		destroy_sched_domain(sd);
+		sd = parent;
+	}
+}
+
+static void destroy_sched_domains(struct sched_domain *sd)
+{
+	if (sd)
+		call_rcu(&sd->rcu, destroy_sched_domains_rcu);
+}
+
+/*
+ * Keep a special pointer to the highest sched_domain that has
+ * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
+ * allows us to avoid some pointer chasing select_idle_sibling().
+ *
+ * Also keep a unique ID per domain (we use the first CPU number in
+ * the cpumask of the domain), this allows us to quickly tell if
+ * two CPUs are in the same cache domain, see cpus_share_cache().
+ */
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_llc);
+DEFINE_PER_CPU(int, sd_llc_size);
+DEFINE_PER_CPU(int, sd_llc_id);
+DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
+DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity);
+
+static void update_top_cache_domain(int cpu)
+{
+	struct sched_domain_shared *sds = NULL;
+	struct sched_domain *sd;
+	int id = cpu;
+	int size = 1;
+
+	sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
+	if (sd) {
+		id = cpumask_first(sched_domain_span(sd));
+		size = cpumask_weight(sched_domain_span(sd));
+		sds = sd->shared;
+	}
+
+	rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
+	per_cpu(sd_llc_size, cpu) = size;
+	per_cpu(sd_llc_id, cpu) = id;
+	rcu_assign_pointer(per_cpu(sd_llc_shared, cpu), sds);
+
+	sd = lowest_flag_domain(cpu, SD_NUMA);
+	rcu_assign_pointer(per_cpu(sd_numa, cpu), sd);
+
+	sd = highest_flag_domain(cpu, SD_ASYM_PACKING);
+	rcu_assign_pointer(per_cpu(sd_asym_packing, cpu), sd);
+
+	sd = lowest_flag_domain(cpu, SD_ASYM_CPUCAPACITY_FULL);
+	rcu_assign_pointer(per_cpu(sd_asym_cpucapacity, cpu), sd);
+}
+
+/*
+ * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
+ * hold the hotplug lock.
+ */
+static void
+cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct sched_domain *tmp;
+
+	/* Remove the sched domains which do not contribute to scheduling. */
+	for (tmp = sd; tmp; ) {
+		struct sched_domain *parent = tmp->parent;
+		if (!parent)
+			break;
+
+		if (sd_parent_degenerate(tmp, parent)) {
+			tmp->parent = parent->parent;
+			if (parent->parent)
+				parent->parent->child = tmp;
+			/*
+			 * Transfer SD_PREFER_SIBLING down in case of a
+			 * degenerate parent; the spans match for this
+			 * so the property transfers.
+			 */
+			if (parent->flags & SD_PREFER_SIBLING)
+				tmp->flags |= SD_PREFER_SIBLING;
+			destroy_sched_domain(parent);
+		} else
+			tmp = tmp->parent;
+	}
+
+	if (sd && sd_degenerate(sd)) {
+		tmp = sd;
+		sd = sd->parent;
+		destroy_sched_domain(tmp);
+		if (sd) {
+			struct sched_group *sg = sd->groups;
+
+			/*
+			 * sched groups hold the flags of the child sched
+			 * domain for convenience. Clear such flags since
+			 * the child is being destroyed.
+			 */
+			do {
+				sg->flags = 0;
+			} while (sg != sd->groups);
+
+			sd->child = NULL;
+		}
+	}
+
+	sched_domain_debug(sd, cpu);
+
+	rq_attach_root(rq, rd);
+	tmp = rq->sd;
+	rcu_assign_pointer(rq->sd, sd);
+	dirty_sched_domain_sysctl(cpu);
+	destroy_sched_domains(tmp);
+
+	update_top_cache_domain(cpu);
+}
+
+struct s_data {
+	struct sched_domain * __percpu *sd;
+	struct root_domain	*rd;
+};
+
+enum s_alloc {
+	sa_rootdomain,
+	sa_sd,
+	sa_sd_storage,
+	sa_none,
+};
+
+/*
+ * Return the canonical balance CPU for this group, this is the first CPU
+ * of this group that's also in the balance mask.
+ *
+ * The balance mask are all those CPUs that could actually end up at this
+ * group. See build_balance_mask().
+ *
+ * Also see should_we_balance().
+ */
+int group_balance_cpu(struct sched_group *sg)
+{
+	return cpumask_first(group_balance_mask(sg));
+}
+
+
+/*
+ * NUMA topology (first read the regular topology blurb below)
+ *
+ * Given a node-distance table, for example:
+ *
+ *   node   0   1   2   3
+ *     0:  10  20  30  20
+ *     1:  20  10  20  30
+ *     2:  30  20  10  20
+ *     3:  20  30  20  10
+ *
+ * which represents a 4 node ring topology like:
+ *
+ *   0 ----- 1
+ *   |       |
+ *   |       |
+ *   |       |
+ *   3 ----- 2
+ *
+ * We want to construct domains and groups to represent this. The way we go
+ * about doing this is to build the domains on 'hops'. For each NUMA level we
+ * construct the mask of all nodes reachable in @level hops.
+ *
+ * For the above NUMA topology that gives 3 levels:
+ *
+ * NUMA-2	0-3		0-3		0-3		0-3
+ *  groups:	{0-1,3},{1-3}	{0-2},{0,2-3}	{1-3},{0-1,3}	{0,2-3},{0-2}
+ *
+ * NUMA-1	0-1,3		0-2		1-3		0,2-3
+ *  groups:	{0},{1},{3}	{0},{1},{2}	{1},{2},{3}	{0},{2},{3}
+ *
+ * NUMA-0	0		1		2		3
+ *
+ *
+ * As can be seen; things don't nicely line up as with the regular topology.
+ * When we iterate a domain in child domain chunks some nodes can be
+ * represented multiple times -- hence the "overlap" naming for this part of
+ * the topology.
+ *
+ * In order to minimize this overlap, we only build enough groups to cover the
+ * domain. For instance Node-0 NUMA-2 would only get groups: 0-1,3 and 1-3.
+ *
+ * Because:
+ *
+ *  - the first group of each domain is its child domain; this
+ *    gets us the first 0-1,3
+ *  - the only uncovered node is 2, who's child domain is 1-3.
+ *
+ * However, because of the overlap, computing a unique CPU for each group is
+ * more complicated. Consider for instance the groups of NODE-1 NUMA-2, both
+ * groups include the CPUs of Node-0, while those CPUs would not in fact ever
+ * end up at those groups (they would end up in group: 0-1,3).
+ *
+ * To correct this we have to introduce the group balance mask. This mask
+ * will contain those CPUs in the group that can reach this group given the
+ * (child) domain tree.
+ *
+ * With this we can once again compute balance_cpu and sched_group_capacity
+ * relations.
+ *
+ * XXX include words on how balance_cpu is unique and therefore can be
+ * used for sched_group_capacity links.
+ *
+ *
+ * Another 'interesting' topology is:
+ *
+ *   node   0   1   2   3
+ *     0:  10  20  20  30
+ *     1:  20  10  20  20
+ *     2:  20  20  10  20
+ *     3:  30  20  20  10
+ *
+ * Which looks a little like:
+ *
+ *   0 ----- 1
+ *   |     / |
+ *   |   /   |
+ *   | /     |
+ *   2 ----- 3
+ *
+ * This topology is asymmetric, nodes 1,2 are fully connected, but nodes 0,3
+ * are not.
+ *
+ * This leads to a few particularly weird cases where the sched_domain's are
+ * not of the same number for each CPU. Consider:
+ *
+ * NUMA-2	0-3						0-3
+ *  groups:	{0-2},{1-3}					{1-3},{0-2}
+ *
+ * NUMA-1	0-2		0-3		0-3		1-3
+ *
+ * NUMA-0	0		1		2		3
+ *
+ */
+
+
+/*
+ * Build the balance mask; it contains only those CPUs that can arrive at this
+ * group and should be considered to continue balancing.
+ *
+ * We do this during the group creation pass, therefore the group information
+ * isn't complete yet, however since each group represents a (child) domain we
+ * can fully construct this using the sched_domain bits (which are already
+ * complete).
+ */
+static void
+build_balance_mask(struct sched_domain *sd, struct sched_group *sg, struct cpumask *mask)
+{
+	const struct cpumask *sg_span = sched_group_span(sg);
+	struct sd_data *sdd = sd->private;
+	struct sched_domain *sibling;
+	int i;
+
+	cpumask_clear(mask);
+
+	for_each_cpu(i, sg_span) {
+		sibling = *per_cpu_ptr(sdd->sd, i);
+
+		/*
+		 * Can happen in the asymmetric case, where these siblings are
+		 * unused. The mask will not be empty because those CPUs that
+		 * do have the top domain _should_ span the domain.
+		 */
+		if (!sibling->child)
+			continue;
+
+		/* If we would not end up here, we can't continue from here */
+		if (!cpumask_equal(sg_span, sched_domain_span(sibling->child)))
+			continue;
+
+		cpumask_set_cpu(i, mask);
+	}
+
+	/* We must not have empty masks here */
+	WARN_ON_ONCE(cpumask_empty(mask));
+}
+
+/*
+ * XXX: This creates per-node group entries; since the load-balancer will
+ * immediately access remote memory to construct this group's load-balance
+ * statistics having the groups node local is of dubious benefit.
+ */
+static struct sched_group *
+build_group_from_child_sched_domain(struct sched_domain *sd, int cpu)
+{
+	struct sched_group *sg;
+	struct cpumask *sg_span;
+
+	sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
+			GFP_KERNEL, cpu_to_node(cpu));
+
+	if (!sg)
+		return NULL;
+
+	sg_span = sched_group_span(sg);
+	if (sd->child) {
+		cpumask_copy(sg_span, sched_domain_span(sd->child));
+		sg->flags = sd->child->flags;
+	} else {
+		cpumask_copy(sg_span, sched_domain_span(sd));
+	}
+
+	atomic_inc(&sg->ref);
+	return sg;
+}
+
+static void init_overlap_sched_group(struct sched_domain *sd,
+				     struct sched_group *sg)
+{
+	struct cpumask *mask = sched_domains_tmpmask2;
+	struct sd_data *sdd = sd->private;
+	struct cpumask *sg_span;
+	int cpu;
+
+	build_balance_mask(sd, sg, mask);
+	cpu = cpumask_first(mask);
+
+	sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);
+	if (atomic_inc_return(&sg->sgc->ref) == 1)
+		cpumask_copy(group_balance_mask(sg), mask);
+	else
+		WARN_ON_ONCE(!cpumask_equal(group_balance_mask(sg), mask));
+
+	/*
+	 * Initialize sgc->capacity such that even if we mess up the
+	 * domains and no possible iteration will get us here, we won't
+	 * die on a /0 trap.
+	 */
+	sg_span = sched_group_span(sg);
+	sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span);
+	sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
+	sg->sgc->max_capacity = SCHED_CAPACITY_SCALE;
+}
+
+static struct sched_domain *
+find_descended_sibling(struct sched_domain *sd, struct sched_domain *sibling)
+{
+	/*
+	 * The proper descendant would be the one whose child won't span out
+	 * of sd
+	 */
+	while (sibling->child &&
+	       !cpumask_subset(sched_domain_span(sibling->child),
+			       sched_domain_span(sd)))
+		sibling = sibling->child;
+
+	/*
+	 * As we are referencing sgc across different topology level, we need
+	 * to go down to skip those sched_domains which don't contribute to
+	 * scheduling because they will be degenerated in cpu_attach_domain
+	 */
+	while (sibling->child &&
+	       cpumask_equal(sched_domain_span(sibling->child),
+			     sched_domain_span(sibling)))
+		sibling = sibling->child;
+
+	return sibling;
+}
+
+static int
+build_overlap_sched_groups(struct sched_domain *sd, int cpu)
+{
+	struct sched_group *first = NULL, *last = NULL, *sg;
+	const struct cpumask *span = sched_domain_span(sd);
+	struct cpumask *covered = sched_domains_tmpmask;
+	struct sd_data *sdd = sd->private;
+	struct sched_domain *sibling;
+	int i;
+
+	cpumask_clear(covered);
+
+	for_each_cpu_wrap(i, span, cpu) {
+		struct cpumask *sg_span;
+
+		if (cpumask_test_cpu(i, covered))
+			continue;
+
+		sibling = *per_cpu_ptr(sdd->sd, i);
+
+		/*
+		 * Asymmetric node setups can result in situations where the
+		 * domain tree is of unequal depth, make sure to skip domains
+		 * that already cover the entire range.
+		 *
+		 * In that case build_sched_domains() will have terminated the
+		 * iteration early and our sibling sd spans will be empty.
+		 * Domains should always include the CPU they're built on, so
+		 * check that.
+		 */
+		if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
+			continue;
+
+		/*
+		 * Usually we build sched_group by sibling's child sched_domain
+		 * But for machines whose NUMA diameter are 3 or above, we move
+		 * to build sched_group by sibling's proper descendant's child
+		 * domain because sibling's child sched_domain will span out of
+		 * the sched_domain being built as below.
+		 *
+		 * Smallest diameter=3 topology is:
+		 *
+		 *   node   0   1   2   3
+		 *     0:  10  20  30  40
+		 *     1:  20  10  20  30
+		 *     2:  30  20  10  20
+		 *     3:  40  30  20  10
+		 *
+		 *   0 --- 1 --- 2 --- 3
+		 *
+		 * NUMA-3       0-3             N/A             N/A             0-3
+		 *  groups:     {0-2},{1-3}                                     {1-3},{0-2}
+		 *
+		 * NUMA-2       0-2             0-3             0-3             1-3
+		 *  groups:     {0-1},{1-3}     {0-2},{2-3}     {1-3},{0-1}     {2-3},{0-2}
+		 *
+		 * NUMA-1       0-1             0-2             1-3             2-3
+		 *  groups:     {0},{1}         {1},{2},{0}     {2},{3},{1}     {3},{2}
+		 *
+		 * NUMA-0       0               1               2               3
+		 *
+		 * The NUMA-2 groups for nodes 0 and 3 are obviously buggered, as the
+		 * group span isn't a subset of the domain span.
+		 */
+		if (sibling->child &&
+		    !cpumask_subset(sched_domain_span(sibling->child), span))
+			sibling = find_descended_sibling(sd, sibling);
+
+		sg = build_group_from_child_sched_domain(sibling, cpu);
+		if (!sg)
+			goto fail;
+
+		sg_span = sched_group_span(sg);
+		cpumask_or(covered, covered, sg_span);
+
+		init_overlap_sched_group(sibling, sg);
+
+		if (!first)
+			first = sg;
+		if (last)
+			last->next = sg;
+		last = sg;
+		last->next = first;
+	}
+	sd->groups = first;
+
+	return 0;
+
+fail:
+	free_sched_groups(first, 0);
+
+	return -ENOMEM;
+}
+
+
+/*
+ * Package topology (also see the load-balance blurb in fair.c)
+ *
+ * The scheduler builds a tree structure to represent a number of important
+ * topology features. By default (default_topology[]) these include:
+ *
+ *  - Simultaneous multithreading (SMT)
+ *  - Multi-Core Cache (MC)
+ *  - Package (DIE)
+ *
+ * Where the last one more or less denotes everything up to a NUMA node.
+ *
+ * The tree consists of 3 primary data structures:
+ *
+ *	sched_domain -> sched_group -> sched_group_capacity
+ *	    ^ ^             ^ ^
+ *          `-'             `-'
+ *
+ * The sched_domains are per-CPU and have a two way link (parent & child) and
+ * denote the ever growing mask of CPUs belonging to that level of topology.
+ *
+ * Each sched_domain has a circular (double) linked list of sched_group's, each
+ * denoting the domains of the level below (or individual CPUs in case of the
+ * first domain level). The sched_group linked by a sched_domain includes the
+ * CPU of that sched_domain [*].
+ *
+ * Take for instance a 2 threaded, 2 core, 2 cache cluster part:
+ *
+ * CPU   0   1   2   3   4   5   6   7
+ *
+ * DIE  [                             ]
+ * MC   [             ] [             ]
+ * SMT  [     ] [     ] [     ] [     ]
+ *
+ *  - or -
+ *
+ * DIE  0-7 0-7 0-7 0-7 0-7 0-7 0-7 0-7
+ * MC	0-3 0-3 0-3 0-3 4-7 4-7 4-7 4-7
+ * SMT  0-1 0-1 2-3 2-3 4-5 4-5 6-7 6-7
+ *
+ * CPU   0   1   2   3   4   5   6   7
+ *
+ * One way to think about it is: sched_domain moves you up and down among these
+ * topology levels, while sched_group moves you sideways through it, at child
+ * domain granularity.
+ *
+ * sched_group_capacity ensures each unique sched_group has shared storage.
+ *
+ * There are two related construction problems, both require a CPU that
+ * uniquely identify each group (for a given domain):
+ *
+ *  - The first is the balance_cpu (see should_we_balance() and the
+ *    load-balance blub in fair.c); for each group we only want 1 CPU to
+ *    continue balancing at a higher domain.
+ *
+ *  - The second is the sched_group_capacity; we want all identical groups
+ *    to share a single sched_group_capacity.
+ *
+ * Since these topologies are exclusive by construction. That is, its
+ * impossible for an SMT thread to belong to multiple cores, and cores to
+ * be part of multiple caches. There is a very clear and unique location
+ * for each CPU in the hierarchy.
+ *
+ * Therefore computing a unique CPU for each group is trivial (the iteration
+ * mask is redundant and set all 1s; all CPUs in a group will end up at _that_
+ * group), we can simply pick the first CPU in each group.
+ *
+ *
+ * [*] in other words, the first group of each domain is its child domain.
+ */
+
+static struct sched_group *get_group(int cpu, struct sd_data *sdd)
+{
+	struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
+	struct sched_domain *child = sd->child;
+	struct sched_group *sg;
+	bool already_visited;
+
+	if (child)
+		cpu = cpumask_first(sched_domain_span(child));
+
+	sg = *per_cpu_ptr(sdd->sg, cpu);
+	sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);
+
+	/* Increase refcounts for claim_allocations: */
+	already_visited = atomic_inc_return(&sg->ref) > 1;
+	/* sgc visits should follow a similar trend as sg */
+	WARN_ON(already_visited != (atomic_inc_return(&sg->sgc->ref) > 1));
+
+	/* If we have already visited that group, it's already initialized. */
+	if (already_visited)
+		return sg;
+
+	if (child) {
+		cpumask_copy(sched_group_span(sg), sched_domain_span(child));
+		cpumask_copy(group_balance_mask(sg), sched_group_span(sg));
+		sg->flags = child->flags;
+	} else {
+		cpumask_set_cpu(cpu, sched_group_span(sg));
+		cpumask_set_cpu(cpu, group_balance_mask(sg));
+	}
+
+	sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sched_group_span(sg));
+	sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;
+	sg->sgc->max_capacity = SCHED_CAPACITY_SCALE;
+
+	return sg;
+}
+
+/*
+ * build_sched_groups will build a circular linked list of the groups
+ * covered by the given span, will set each group's ->cpumask correctly,
+ * and will initialize their ->sgc.
+ *
+ * Assumes the sched_domain tree is fully constructed
+ */
+static int
+build_sched_groups(struct sched_domain *sd, int cpu)
+{
+	struct sched_group *first = NULL, *last = NULL;
+	struct sd_data *sdd = sd->private;
+	const struct cpumask *span = sched_domain_span(sd);
+	struct cpumask *covered;
+	int i;
+
+	lockdep_assert_held(&sched_domains_mutex);
+	covered = sched_domains_tmpmask;
+
+	cpumask_clear(covered);
+
+	for_each_cpu_wrap(i, span, cpu) {
+		struct sched_group *sg;
+
+		if (cpumask_test_cpu(i, covered))
+			continue;
+
+		sg = get_group(i, sdd);
+
+		cpumask_or(covered, covered, sched_group_span(sg));
+
+		if (!first)
+			first = sg;
+		if (last)
+			last->next = sg;
+		last = sg;
+	}
+	last->next = first;
+	sd->groups = first;
+
+	return 0;
+}
+
+/*
+ * Initialize sched groups cpu_capacity.
+ *
+ * cpu_capacity indicates the capacity of sched group, which is used while
+ * distributing the load between different sched groups in a sched domain.
+ * Typically cpu_capacity for all the groups in a sched domain will be same
+ * unless there are asymmetries in the topology. If there are asymmetries,
+ * group having more cpu_capacity will pickup more load compared to the
+ * group having less cpu_capacity.
+ */
+static void init_sched_groups_capacity(int cpu, struct sched_domain *sd)
+{
+	struct sched_group *sg = sd->groups;
+
+	WARN_ON(!sg);
+
+	do {
+		int cpu, max_cpu = -1;
+
+		sg->group_weight = cpumask_weight(sched_group_span(sg));
+
+		if (!(sd->flags & SD_ASYM_PACKING))
+			goto next;
+
+		for_each_cpu(cpu, sched_group_span(sg)) {
+			if (max_cpu < 0)
+				max_cpu = cpu;
+			else if (sched_asym_prefer(cpu, max_cpu))
+				max_cpu = cpu;
+		}
+		sg->asym_prefer_cpu = max_cpu;
+
+next:
+		sg = sg->next;
+	} while (sg != sd->groups);
+
+	if (cpu != group_balance_cpu(sg))
+		return;
+
+	update_group_capacity(sd, cpu);
+}
+
+/*
+ * Asymmetric CPU capacity bits
+ */
+struct asym_cap_data {
+	struct list_head link;
+	unsigned long capacity;
+	unsigned long cpus[];
+};
+
+/*
+ * Set of available CPUs grouped by their corresponding capacities
+ * Each list entry contains a CPU mask reflecting CPUs that share the same
+ * capacity.
+ * The lifespan of data is unlimited.
+ */
+static LIST_HEAD(asym_cap_list);
+
+#define cpu_capacity_span(asym_data) to_cpumask((asym_data)->cpus)
+
+/*
+ * Verify whether there is any CPU capacity asymmetry in a given sched domain.
+ * Provides sd_flags reflecting the asymmetry scope.
+ */
+static inline int
+asym_cpu_capacity_classify(const struct cpumask *sd_span,
+			   const struct cpumask *cpu_map)
+{
+	struct asym_cap_data *entry;
+	int count = 0, miss = 0;
+
+	/*
+	 * Count how many unique CPU capacities this domain spans across
+	 * (compare sched_domain CPUs mask with ones representing  available
+	 * CPUs capacities). Take into account CPUs that might be offline:
+	 * skip those.
+	 */
+	list_for_each_entry(entry, &asym_cap_list, link) {
+		if (cpumask_intersects(sd_span, cpu_capacity_span(entry)))
+			++count;
+		else if (cpumask_intersects(cpu_map, cpu_capacity_span(entry)))
+			++miss;
+	}
+
+	WARN_ON_ONCE(!count && !list_empty(&asym_cap_list));
+
+	/* No asymmetry detected */
+	if (count < 2)
+		return 0;
+	/* Some of the available CPU capacity values have not been detected */
+	if (miss)
+		return SD_ASYM_CPUCAPACITY;
+
+	/* Full asymmetry */
+	return SD_ASYM_CPUCAPACITY | SD_ASYM_CPUCAPACITY_FULL;
+
+}
+
+static inline void asym_cpu_capacity_update_data(int cpu)
+{
+	unsigned long capacity = arch_scale_cpu_capacity(cpu);
+	struct asym_cap_data *entry = NULL;
+
+	list_for_each_entry(entry, &asym_cap_list, link) {
+		if (capacity == entry->capacity)
+			goto done;
+	}
+
+	entry = kzalloc(sizeof(*entry) + cpumask_size(), GFP_KERNEL);
+	if (WARN_ONCE(!entry, "Failed to allocate memory for asymmetry data\n"))
+		return;
+	entry->capacity = capacity;
+	list_add(&entry->link, &asym_cap_list);
+done:
+	__cpumask_set_cpu(cpu, cpu_capacity_span(entry));
+}
+
+/*
+ * Build-up/update list of CPUs grouped by their capacities
+ * An update requires explicit request to rebuild sched domains
+ * with state indicating CPU topology changes.
+ */
+static void asym_cpu_capacity_scan(void)
+{
+	struct asym_cap_data *entry, *next;
+	int cpu;
+
+	list_for_each_entry(entry, &asym_cap_list, link)
+		cpumask_clear(cpu_capacity_span(entry));
+
+	for_each_cpu_and(cpu, cpu_possible_mask, housekeeping_cpumask(HK_TYPE_DOMAIN))
+		asym_cpu_capacity_update_data(cpu);
+
+	list_for_each_entry_safe(entry, next, &asym_cap_list, link) {
+		if (cpumask_empty(cpu_capacity_span(entry))) {
+			list_del(&entry->link);
+			kfree(entry);
+		}
+	}
+
+	/*
+	 * Only one capacity value has been detected i.e. this system is symmetric.
+	 * No need to keep this data around.
+	 */
+	if (list_is_singular(&asym_cap_list)) {
+		entry = list_first_entry(&asym_cap_list, typeof(*entry), link);
+		list_del(&entry->link);
+		kfree(entry);
+	}
+}
+
+/*
+ * Initializers for schedule domains
+ * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
+ */
+
+static int default_relax_domain_level = -1;
+int sched_domain_level_max;
+
+static int __init setup_relax_domain_level(char *str)
+{
+	if (kstrtoint(str, 0, &default_relax_domain_level))
+		pr_warn("Unable to set relax_domain_level\n");
+
+	return 1;
+}
+__setup("relax_domain_level=", setup_relax_domain_level);
+
+static void set_domain_attribute(struct sched_domain *sd,
+				 struct sched_domain_attr *attr)
+{
+	int request;
+
+	if (!attr || attr->relax_domain_level < 0) {
+		if (default_relax_domain_level < 0)
+			return;
+		request = default_relax_domain_level;
+	} else
+		request = attr->relax_domain_level;
+
+	if (sd->level > request) {
+		/* Turn off idle balance on this domain: */
+		sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
+	}
+}
+
+static void __sdt_free(const struct cpumask *cpu_map);
+static int __sdt_alloc(const struct cpumask *cpu_map);
+
+static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
+				 const struct cpumask *cpu_map)
+{
+	switch (what) {
+	case sa_rootdomain:
+		if (!atomic_read(&d->rd->refcount))
+			free_rootdomain(&d->rd->rcu);
+		fallthrough;
+	case sa_sd:
+		free_percpu(d->sd);
+		fallthrough;
+	case sa_sd_storage:
+		__sdt_free(cpu_map);
+		fallthrough;
+	case sa_none:
+		break;
+	}
+}
+
+static enum s_alloc
+__visit_domain_allocation_hell(struct s_data *d, const struct cpumask *cpu_map)
+{
+	memset(d, 0, sizeof(*d));
+
+	if (__sdt_alloc(cpu_map))
+		return sa_sd_storage;
+	d->sd = alloc_percpu(struct sched_domain *);
+	if (!d->sd)
+		return sa_sd_storage;
+	d->rd = alloc_rootdomain();
+	if (!d->rd)
+		return sa_sd;
+
+	return sa_rootdomain;
+}
+
+/*
+ * NULL the sd_data elements we've used to build the sched_domain and
+ * sched_group structure so that the subsequent __free_domain_allocs()
+ * will not free the data we're using.
+ */
+static void claim_allocations(int cpu, struct sched_domain *sd)
+{
+	struct sd_data *sdd = sd->private;
+
+	WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
+	*per_cpu_ptr(sdd->sd, cpu) = NULL;
+
+	if (atomic_read(&(*per_cpu_ptr(sdd->sds, cpu))->ref))
+		*per_cpu_ptr(sdd->sds, cpu) = NULL;
+
+	if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
+		*per_cpu_ptr(sdd->sg, cpu) = NULL;
+
+	if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref))
+		*per_cpu_ptr(sdd->sgc, cpu) = NULL;
+}
+
+#ifdef CONFIG_NUMA
+enum numa_topology_type sched_numa_topology_type;
+
+static int			sched_domains_numa_levels;
+static int			sched_domains_curr_level;
+
+int				sched_max_numa_distance;
+static int			*sched_domains_numa_distance;
+static struct cpumask		***sched_domains_numa_masks;
+#endif
+
+/*
+ * SD_flags allowed in topology descriptions.
+ *
+ * These flags are purely descriptive of the topology and do not prescribe
+ * behaviour. Behaviour is artificial and mapped in the below sd_init()
+ * function:
+ *
+ *   SD_SHARE_CPUCAPACITY   - describes SMT topologies
+ *   SD_SHARE_PKG_RESOURCES - describes shared caches
+ *   SD_NUMA                - describes NUMA topologies
+ *
+ * Odd one out, which beside describing the topology has a quirk also
+ * prescribes the desired behaviour that goes along with it:
+ *
+ *   SD_ASYM_PACKING        - describes SMT quirks
+ */
+#define TOPOLOGY_SD_FLAGS		\
+	(SD_SHARE_CPUCAPACITY	|	\
+	 SD_SHARE_PKG_RESOURCES |	\
+	 SD_NUMA		|	\
+	 SD_ASYM_PACKING)
+
+static struct sched_domain *
+sd_init(struct sched_domain_topology_level *tl,
+	const struct cpumask *cpu_map,
+	struct sched_domain *child, int cpu)
+{
+	struct sd_data *sdd = &tl->data;
+	struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
+	int sd_id, sd_weight, sd_flags = 0;
+	struct cpumask *sd_span;
+
+#ifdef CONFIG_NUMA
+	/*
+	 * Ugly hack to pass state to sd_numa_mask()...
+	 */
+	sched_domains_curr_level = tl->numa_level;
+#endif
+
+	sd_weight = cpumask_weight(tl->mask(cpu));
+
+	if (tl->sd_flags)
+		sd_flags = (*tl->sd_flags)();
+	if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS,
+			"wrong sd_flags in topology description\n"))
+		sd_flags &= TOPOLOGY_SD_FLAGS;
+
+	*sd = (struct sched_domain){
+		.min_interval		= sd_weight,
+		.max_interval		= 2*sd_weight,
+		.busy_factor		= 16,
+		.imbalance_pct		= 117,
+
+		.cache_nice_tries	= 0,
+
+		.flags			= 1*SD_BALANCE_NEWIDLE
+					| 1*SD_BALANCE_EXEC
+					| 1*SD_BALANCE_FORK
+					| 0*SD_BALANCE_WAKE
+					| 1*SD_WAKE_AFFINE
+					| 0*SD_SHARE_CPUCAPACITY
+					| 0*SD_SHARE_PKG_RESOURCES
+					| 0*SD_SERIALIZE
+					| 1*SD_PREFER_SIBLING
+					| 0*SD_NUMA
+					| sd_flags
+					,
+
+		.last_balance		= jiffies,
+		.balance_interval	= sd_weight,
+		.max_newidle_lb_cost	= 0,
+		.last_decay_max_lb_cost	= jiffies,
+		.child			= child,
+#ifdef CONFIG_SCHED_DEBUG
+		.name			= tl->name,
+#endif
+	};
+
+	sd_span = sched_domain_span(sd);
+	cpumask_and(sd_span, cpu_map, tl->mask(cpu));
+	sd_id = cpumask_first(sd_span);
+
+	sd->flags |= asym_cpu_capacity_classify(sd_span, cpu_map);
+
+	WARN_ONCE((sd->flags & (SD_SHARE_CPUCAPACITY | SD_ASYM_CPUCAPACITY)) ==
+		  (SD_SHARE_CPUCAPACITY | SD_ASYM_CPUCAPACITY),
+		  "CPU capacity asymmetry not supported on SMT\n");
+
+	/*
+	 * Convert topological properties into behaviour.
+	 */
+	/* Don't attempt to spread across CPUs of different capacities. */
+	if ((sd->flags & SD_ASYM_CPUCAPACITY) && sd->child)
+		sd->child->flags &= ~SD_PREFER_SIBLING;
+
+	if (sd->flags & SD_SHARE_CPUCAPACITY) {
+		sd->imbalance_pct = 110;
+
+	} else if (sd->flags & SD_SHARE_PKG_RESOURCES) {
+		sd->imbalance_pct = 117;
+		sd->cache_nice_tries = 1;
+
+#ifdef CONFIG_NUMA
+	} else if (sd->flags & SD_NUMA) {
+		sd->cache_nice_tries = 2;
+
+		sd->flags &= ~SD_PREFER_SIBLING;
+		sd->flags |= SD_SERIALIZE;
+		if (sched_domains_numa_distance[tl->numa_level] > node_reclaim_distance) {
+			sd->flags &= ~(SD_BALANCE_EXEC |
+				       SD_BALANCE_FORK |
+				       SD_WAKE_AFFINE);
+		}
+
+#endif
+	} else {
+		sd->cache_nice_tries = 1;
+	}
+
+	/*
+	 * For all levels sharing cache; connect a sched_domain_shared
+	 * instance.
+	 */
+	if (sd->flags & SD_SHARE_PKG_RESOURCES) {
+		sd->shared = *per_cpu_ptr(sdd->sds, sd_id);
+		atomic_inc(&sd->shared->ref);
+		atomic_set(&sd->shared->nr_busy_cpus, sd_weight);
+	}
+
+	sd->private = sdd;
+
+	return sd;
+}
+
+/*
+ * Topology list, bottom-up.
+ */
+static struct sched_domain_topology_level default_topology[] = {
+#ifdef CONFIG_SCHED_SMT
+	{ cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
+#endif
+
+#ifdef CONFIG_SCHED_CLUSTER
+	{ cpu_clustergroup_mask, cpu_cluster_flags, SD_INIT_NAME(CLS) },
+#endif
+
+#ifdef CONFIG_SCHED_MC
+	{ cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
+#endif
+	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
+	{ NULL, },
+};
+
+static struct sched_domain_topology_level *sched_domain_topology =
+	default_topology;
+static struct sched_domain_topology_level *sched_domain_topology_saved;
+
+#define for_each_sd_topology(tl)			\
+	for (tl = sched_domain_topology; tl->mask; tl++)
+
+void set_sched_topology(struct sched_domain_topology_level *tl)
+{
+	if (WARN_ON_ONCE(sched_smp_initialized))
+		return;
+
+	sched_domain_topology = tl;
+	sched_domain_topology_saved = NULL;
+}
+
+#ifdef CONFIG_NUMA
+
+static const struct cpumask *sd_numa_mask(int cpu)
+{
+	return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)];
+}
+
+static void sched_numa_warn(const char *str)
+{
+	static int done = false;
+	int i,j;
+
+	if (done)
+		return;
+
+	done = true;
+
+	printk(KERN_WARNING "ERROR: %s\n\n", str);
+
+	for (i = 0; i < nr_node_ids; i++) {
+		printk(KERN_WARNING "  ");
+		for (j = 0; j < nr_node_ids; j++) {
+			if (!node_state(i, N_CPU) || !node_state(j, N_CPU))
+				printk(KERN_CONT "(%02d) ", node_distance(i,j));
+			else
+				printk(KERN_CONT " %02d  ", node_distance(i,j));
+		}
+		printk(KERN_CONT "\n");
+	}
+	printk(KERN_WARNING "\n");
+}
+
+bool find_numa_distance(int distance)
+{
+	bool found = false;
+	int i, *distances;
+
+	if (distance == node_distance(0, 0))
+		return true;
+
+	rcu_read_lock();
+	distances = rcu_dereference(sched_domains_numa_distance);
+	if (!distances)
+		goto unlock;
+	for (i = 0; i < sched_domains_numa_levels; i++) {
+		if (distances[i] == distance) {
+			found = true;
+			break;
+		}
+	}
+unlock:
+	rcu_read_unlock();
+
+	return found;
+}
+
+#define for_each_cpu_node_but(n, nbut)		\
+	for_each_node_state(n, N_CPU)		\
+		if (n == nbut)			\
+			continue;		\
+		else
+
+/*
+ * A system can have three types of NUMA topology:
+ * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system
+ * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes
+ * NUMA_BACKPLANE: nodes can reach other nodes through a backplane
+ *
+ * The difference between a glueless mesh topology and a backplane
+ * topology lies in whether communication between not directly
+ * connected nodes goes through intermediary nodes (where programs
+ * could run), or through backplane controllers. This affects
+ * placement of programs.
+ *
+ * The type of topology can be discerned with the following tests:
+ * - If the maximum distance between any nodes is 1 hop, the system
+ *   is directly connected.
+ * - If for two nodes A and B, located N > 1 hops away from each other,
+ *   there is an intermediary node C, which is < N hops away from both
+ *   nodes A and B, the system is a glueless mesh.
+ */
+static void init_numa_topology_type(int offline_node)
+{
+	int a, b, c, n;
+
+	n = sched_max_numa_distance;
+
+	if (sched_domains_numa_levels <= 2) {
+		sched_numa_topology_type = NUMA_DIRECT;
+		return;
+	}
+
+	for_each_cpu_node_but(a, offline_node) {
+		for_each_cpu_node_but(b, offline_node) {
+			/* Find two nodes furthest removed from each other. */
+			if (node_distance(a, b) < n)
+				continue;
+
+			/* Is there an intermediary node between a and b? */
+			for_each_cpu_node_but(c, offline_node) {
+				if (node_distance(a, c) < n &&
+				    node_distance(b, c) < n) {
+					sched_numa_topology_type =
+							NUMA_GLUELESS_MESH;
+					return;
+				}
+			}
+
+			sched_numa_topology_type = NUMA_BACKPLANE;
+			return;
+		}
+	}
+
+	pr_err("Failed to find a NUMA topology type, defaulting to DIRECT\n");
+	sched_numa_topology_type = NUMA_DIRECT;
+}
+
+
+#define NR_DISTANCE_VALUES (1 << DISTANCE_BITS)
+
+void sched_init_numa(int offline_node)
+{
+	struct sched_domain_topology_level *tl;
+	unsigned long *distance_map;
+	int nr_levels = 0;
+	int i, j;
+	int *distances;
+	struct cpumask ***masks;
+
+	/*
+	 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
+	 * unique distances in the node_distance() table.
+	 */
+	distance_map = bitmap_alloc(NR_DISTANCE_VALUES, GFP_KERNEL);
+	if (!distance_map)
+		return;
+
+	bitmap_zero(distance_map, NR_DISTANCE_VALUES);
+	for_each_cpu_node_but(i, offline_node) {
+		for_each_cpu_node_but(j, offline_node) {
+			int distance = node_distance(i, j);
+
+			if (distance < LOCAL_DISTANCE || distance >= NR_DISTANCE_VALUES) {
+				sched_numa_warn("Invalid distance value range");
+				bitmap_free(distance_map);
+				return;
+			}
+
+			bitmap_set(distance_map, distance, 1);
+		}
+	}
+	/*
+	 * We can now figure out how many unique distance values there are and
+	 * allocate memory accordingly.
+	 */
+	nr_levels = bitmap_weight(distance_map, NR_DISTANCE_VALUES);
+
+	distances = kcalloc(nr_levels, sizeof(int), GFP_KERNEL);
+	if (!distances) {
+		bitmap_free(distance_map);
+		return;
+	}
+
+	for (i = 0, j = 0; i < nr_levels; i++, j++) {
+		j = find_next_bit(distance_map, NR_DISTANCE_VALUES, j);
+		distances[i] = j;
+	}
+	rcu_assign_pointer(sched_domains_numa_distance, distances);
+
+	bitmap_free(distance_map);
+
+	/*
+	 * 'nr_levels' contains the number of unique distances
+	 *
+	 * The sched_domains_numa_distance[] array includes the actual distance
+	 * numbers.
+	 */
+
+	/*
+	 * Here, we should temporarily reset sched_domains_numa_levels to 0.
+	 * If it fails to allocate memory for array sched_domains_numa_masks[][],
+	 * the array will contain less then 'nr_levels' members. This could be
+	 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
+	 * in other functions.
+	 *
+	 * We reset it to 'nr_levels' at the end of this function.
+	 */
+	sched_domains_numa_levels = 0;
+
+	masks = kzalloc(sizeof(void *) * nr_levels, GFP_KERNEL);
+	if (!masks)
+		return;
+
+	/*
+	 * Now for each level, construct a mask per node which contains all
+	 * CPUs of nodes that are that many hops away from us.
+	 */
+	for (i = 0; i < nr_levels; i++) {
+		masks[i] = kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
+		if (!masks[i])
+			return;
+
+		for_each_cpu_node_but(j, offline_node) {
+			struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
+			int k;
+
+			if (!mask)
+				return;
+
+			masks[i][j] = mask;
+
+			for_each_cpu_node_but(k, offline_node) {
+				if (sched_debug() && (node_distance(j, k) != node_distance(k, j)))
+					sched_numa_warn("Node-distance not symmetric");
+
+				if (node_distance(j, k) > sched_domains_numa_distance[i])
+					continue;
+
+				cpumask_or(mask, mask, cpumask_of_node(k));
+			}
+		}
+	}
+	rcu_assign_pointer(sched_domains_numa_masks, masks);
+
+	/* Compute default topology size */
+	for (i = 0; sched_domain_topology[i].mask; i++);
+
+	tl = kzalloc((i + nr_levels + 1) *
+			sizeof(struct sched_domain_topology_level), GFP_KERNEL);
+	if (!tl)
+		return;
+
+	/*
+	 * Copy the default topology bits..
+	 */
+	for (i = 0; sched_domain_topology[i].mask; i++)
+		tl[i] = sched_domain_topology[i];
+
+	/*
+	 * Add the NUMA identity distance, aka single NODE.
+	 */
+	tl[i++] = (struct sched_domain_topology_level){
+		.mask = sd_numa_mask,
+		.numa_level = 0,
+		SD_INIT_NAME(NODE)
+	};
+
+	/*
+	 * .. and append 'j' levels of NUMA goodness.
+	 */
+	for (j = 1; j < nr_levels; i++, j++) {
+		tl[i] = (struct sched_domain_topology_level){
+			.mask = sd_numa_mask,
+			.sd_flags = cpu_numa_flags,
+			.flags = SDTL_OVERLAP,
+			.numa_level = j,
+			SD_INIT_NAME(NUMA)
+		};
+	}
+
+	sched_domain_topology_saved = sched_domain_topology;
+	sched_domain_topology = tl;
+
+	sched_domains_numa_levels = nr_levels;
+	WRITE_ONCE(sched_max_numa_distance, sched_domains_numa_distance[nr_levels - 1]);
+
+	init_numa_topology_type(offline_node);
+}
+
+
+static void sched_reset_numa(void)
+{
+	int nr_levels, *distances;
+	struct cpumask ***masks;
+
+	nr_levels = sched_domains_numa_levels;
+	sched_domains_numa_levels = 0;
+	sched_max_numa_distance = 0;
+	sched_numa_topology_type = NUMA_DIRECT;
+	distances = sched_domains_numa_distance;
+	rcu_assign_pointer(sched_domains_numa_distance, NULL);
+	masks = sched_domains_numa_masks;
+	rcu_assign_pointer(sched_domains_numa_masks, NULL);
+	if (distances || masks) {
+		int i, j;
+
+		synchronize_rcu();
+		kfree(distances);
+		for (i = 0; i < nr_levels && masks; i++) {
+			if (!masks[i])
+				continue;
+			for_each_node(j)
+				kfree(masks[i][j]);
+			kfree(masks[i]);
+		}
+		kfree(masks);
+	}
+	if (sched_domain_topology_saved) {
+		kfree(sched_domain_topology);
+		sched_domain_topology = sched_domain_topology_saved;
+		sched_domain_topology_saved = NULL;
+	}
+}
+
+/*
+ * Call with hotplug lock held
+ */
+void sched_update_numa(int cpu, bool online)
+{
+	int node;
+
+	node = cpu_to_node(cpu);
+	/*
+	 * Scheduler NUMA topology is updated when the first CPU of a
+	 * node is onlined or the last CPU of a node is offlined.
+	 */
+	if (cpumask_weight(cpumask_of_node(node)) != 1)
+		return;
+
+	sched_reset_numa();
+	sched_init_numa(online ? NUMA_NO_NODE : node);
+}
+
+void sched_domains_numa_masks_set(unsigned int cpu)
+{
+	int node = cpu_to_node(cpu);
+	int i, j;
+
+	for (i = 0; i < sched_domains_numa_levels; i++) {
+		for (j = 0; j < nr_node_ids; j++) {
+			if (!node_state(j, N_CPU))
+				continue;
+
+			/* Set ourselves in the remote node's masks */
+			if (node_distance(j, node) <= sched_domains_numa_distance[i])
+				cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]);
+		}
+	}
+}
+
+void sched_domains_numa_masks_clear(unsigned int cpu)
+{
+	int i, j;
+
+	for (i = 0; i < sched_domains_numa_levels; i++) {
+		for (j = 0; j < nr_node_ids; j++) {
+			if (sched_domains_numa_masks[i][j])
+				cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
+		}
+	}
+}
+
+/*
+ * sched_numa_find_closest() - given the NUMA topology, find the cpu
+ *                             closest to @cpu from @cpumask.
+ * cpumask: cpumask to find a cpu from
+ * cpu: cpu to be close to
+ *
+ * returns: cpu, or nr_cpu_ids when nothing found.
+ */
+int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
+{
+	int i, j = cpu_to_node(cpu), found = nr_cpu_ids;
+	struct cpumask ***masks;
+
+	rcu_read_lock();
+	masks = rcu_dereference(sched_domains_numa_masks);
+	if (!masks)
+		goto unlock;
+	for (i = 0; i < sched_domains_numa_levels; i++) {
+		if (!masks[i][j])
+			break;
+		cpu = cpumask_any_and(cpus, masks[i][j]);
+		if (cpu < nr_cpu_ids) {
+			found = cpu;
+			break;
+		}
+	}
+unlock:
+	rcu_read_unlock();
+
+	return found;
+}
+
+#endif /* CONFIG_NUMA */
+
+static int __sdt_alloc(const struct cpumask *cpu_map)
+{
+	struct sched_domain_topology_level *tl;
+	int j;
+
+	for_each_sd_topology(tl) {
+		struct sd_data *sdd = &tl->data;
+
+		sdd->sd = alloc_percpu(struct sched_domain *);
+		if (!sdd->sd)
+			return -ENOMEM;
+
+		sdd->sds = alloc_percpu(struct sched_domain_shared *);
+		if (!sdd->sds)
+			return -ENOMEM;
+
+		sdd->sg = alloc_percpu(struct sched_group *);
+		if (!sdd->sg)
+			return -ENOMEM;
+
+		sdd->sgc = alloc_percpu(struct sched_group_capacity *);
+		if (!sdd->sgc)
+			return -ENOMEM;
+
+		for_each_cpu(j, cpu_map) {
+			struct sched_domain *sd;
+			struct sched_domain_shared *sds;
+			struct sched_group *sg;
+			struct sched_group_capacity *sgc;
+
+			sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
+					GFP_KERNEL, cpu_to_node(j));
+			if (!sd)
+				return -ENOMEM;
+
+			*per_cpu_ptr(sdd->sd, j) = sd;
+
+			sds = kzalloc_node(sizeof(struct sched_domain_shared),
+					GFP_KERNEL, cpu_to_node(j));
+			if (!sds)
+				return -ENOMEM;
+
+			*per_cpu_ptr(sdd->sds, j) = sds;
+
+			sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
+					GFP_KERNEL, cpu_to_node(j));
+			if (!sg)
+				return -ENOMEM;
+
+			sg->next = sg;
+
+			*per_cpu_ptr(sdd->sg, j) = sg;
+
+			sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(),
+					GFP_KERNEL, cpu_to_node(j));
+			if (!sgc)
+				return -ENOMEM;
+
+#ifdef CONFIG_SCHED_DEBUG
+			sgc->id = j;
+#endif
+
+			*per_cpu_ptr(sdd->sgc, j) = sgc;
+		}
+	}
+
+	return 0;
+}
+
+static void __sdt_free(const struct cpumask *cpu_map)
+{
+	struct sched_domain_topology_level *tl;
+	int j;
+
+	for_each_sd_topology(tl) {
+		struct sd_data *sdd = &tl->data;
+
+		for_each_cpu(j, cpu_map) {
+			struct sched_domain *sd;
+
+			if (sdd->sd) {
+				sd = *per_cpu_ptr(sdd->sd, j);
+				if (sd && (sd->flags & SD_OVERLAP))
+					free_sched_groups(sd->groups, 0);
+				kfree(*per_cpu_ptr(sdd->sd, j));
+			}
+
+			if (sdd->sds)
+				kfree(*per_cpu_ptr(sdd->sds, j));
+			if (sdd->sg)
+				kfree(*per_cpu_ptr(sdd->sg, j));
+			if (sdd->sgc)
+				kfree(*per_cpu_ptr(sdd->sgc, j));
+		}
+		free_percpu(sdd->sd);
+		sdd->sd = NULL;
+		free_percpu(sdd->sds);
+		sdd->sds = NULL;
+		free_percpu(sdd->sg);
+		sdd->sg = NULL;
+		free_percpu(sdd->sgc);
+		sdd->sgc = NULL;
+	}
+}
+
+static struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
+		const struct cpumask *cpu_map, struct sched_domain_attr *attr,
+		struct sched_domain *child, int cpu)
+{
+	struct sched_domain *sd = sd_init(tl, cpu_map, child, cpu);
+
+	if (child) {
+		sd->level = child->level + 1;
+		sched_domain_level_max = max(sched_domain_level_max, sd->level);
+		child->parent = sd;
+
+		if (!cpumask_subset(sched_domain_span(child),
+				    sched_domain_span(sd))) {
+			pr_err("BUG: arch topology borken\n");
+#ifdef CONFIG_SCHED_DEBUG
+			pr_err("     the %s domain not a subset of the %s domain\n",
+					child->name, sd->name);
+#endif
+			/* Fixup, ensure @sd has at least @child CPUs. */
+			cpumask_or(sched_domain_span(sd),
+				   sched_domain_span(sd),
+				   sched_domain_span(child));
+		}
+
+	}
+	set_domain_attribute(sd, attr);
+
+	return sd;
+}
+
+/*
+ * Ensure topology masks are sane, i.e. there are no conflicts (overlaps) for
+ * any two given CPUs at this (non-NUMA) topology level.
+ */
+static bool topology_span_sane(struct sched_domain_topology_level *tl,
+			      const struct cpumask *cpu_map, int cpu)
+{
+	int i;
+
+	/* NUMA levels are allowed to overlap */
+	if (tl->flags & SDTL_OVERLAP)
+		return true;
+
+	/*
+	 * Non-NUMA levels cannot partially overlap - they must be either
+	 * completely equal or completely disjoint. Otherwise we can end up
+	 * breaking the sched_group lists - i.e. a later get_group() pass
+	 * breaks the linking done for an earlier span.
+	 */
+	for_each_cpu(i, cpu_map) {
+		if (i == cpu)
+			continue;
+		/*
+		 * We should 'and' all those masks with 'cpu_map' to exactly
+		 * match the topology we're about to build, but that can only
+		 * remove CPUs, which only lessens our ability to detect
+		 * overlaps
+		 */
+		if (!cpumask_equal(tl->mask(cpu), tl->mask(i)) &&
+		    cpumask_intersects(tl->mask(cpu), tl->mask(i)))
+			return false;
+	}
+
+	return true;
+}
+
+/*
+ * Build sched domains for a given set of CPUs and attach the sched domains
+ * to the individual CPUs
+ */
+static int
+build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *attr)
+{
+	enum s_alloc alloc_state = sa_none;
+	struct sched_domain *sd;
+	struct s_data d;
+	struct rq *rq = NULL;
+	int i, ret = -ENOMEM;
+	bool has_asym = false;
+
+	if (WARN_ON(cpumask_empty(cpu_map)))
+		goto error;
+
+	alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
+	if (alloc_state != sa_rootdomain)
+		goto error;
+
+	/* Set up domains for CPUs specified by the cpu_map: */
+	for_each_cpu(i, cpu_map) {
+		struct sched_domain_topology_level *tl;
+
+		sd = NULL;
+		for_each_sd_topology(tl) {
+
+			if (WARN_ON(!topology_span_sane(tl, cpu_map, i)))
+				goto error;
+
+			sd = build_sched_domain(tl, cpu_map, attr, sd, i);
+
+			has_asym |= sd->flags & SD_ASYM_CPUCAPACITY;
+
+			if (tl == sched_domain_topology)
+				*per_cpu_ptr(d.sd, i) = sd;
+			if (tl->flags & SDTL_OVERLAP)
+				sd->flags |= SD_OVERLAP;
+			if (cpumask_equal(cpu_map, sched_domain_span(sd)))
+				break;
+		}
+	}
+
+	/* Build the groups for the domains */
+	for_each_cpu(i, cpu_map) {
+		for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
+			sd->span_weight = cpumask_weight(sched_domain_span(sd));
+			if (sd->flags & SD_OVERLAP) {
+				if (build_overlap_sched_groups(sd, i))
+					goto error;
+			} else {
+				if (build_sched_groups(sd, i))
+					goto error;
+			}
+		}
+	}
+
+	/*
+	 * Calculate an allowed NUMA imbalance such that LLCs do not get
+	 * imbalanced.
+	 */
+	for_each_cpu(i, cpu_map) {
+		unsigned int imb = 0;
+		unsigned int imb_span = 1;
+
+		for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
+			struct sched_domain *child = sd->child;
+
+			if (!(sd->flags & SD_SHARE_PKG_RESOURCES) && child &&
+			    (child->flags & SD_SHARE_PKG_RESOURCES)) {
+				struct sched_domain __rcu *top_p;
+				unsigned int nr_llcs;
+
+				/*
+				 * For a single LLC per node, allow an
+				 * imbalance up to 12.5% of the node. This is
+				 * arbitrary cutoff based two factors -- SMT and
+				 * memory channels. For SMT-2, the intent is to
+				 * avoid premature sharing of HT resources but
+				 * SMT-4 or SMT-8 *may* benefit from a different
+				 * cutoff. For memory channels, this is a very
+				 * rough estimate of how many channels may be
+				 * active and is based on recent CPUs with
+				 * many cores.
+				 *
+				 * For multiple LLCs, allow an imbalance
+				 * until multiple tasks would share an LLC
+				 * on one node while LLCs on another node
+				 * remain idle. This assumes that there are
+				 * enough logical CPUs per LLC to avoid SMT
+				 * factors and that there is a correlation
+				 * between LLCs and memory channels.
+				 */
+				nr_llcs = sd->span_weight / child->span_weight;
+				if (nr_llcs == 1)
+					imb = sd->span_weight >> 3;
+				else
+					imb = nr_llcs;
+				imb = max(1U, imb);
+				sd->imb_numa_nr = imb;
+
+				/* Set span based on the first NUMA domain. */
+				top_p = sd->parent;
+				while (top_p && !(top_p->flags & SD_NUMA)) {
+					top_p = top_p->parent;
+				}
+				imb_span = top_p ? top_p->span_weight : sd->span_weight;
+			} else {
+				int factor = max(1U, (sd->span_weight / imb_span));
+
+				sd->imb_numa_nr = imb * factor;
+			}
+		}
+	}
+
+	/* Calculate CPU capacity for physical packages and nodes */
+	for (i = nr_cpumask_bits-1; i >= 0; i--) {
+		if (!cpumask_test_cpu(i, cpu_map))
+			continue;
+
+		for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
+			claim_allocations(i, sd);
+			init_sched_groups_capacity(i, sd);
+		}
+	}
+
+	/* Attach the domains */
+	rcu_read_lock();
+	for_each_cpu(i, cpu_map) {
+		rq = cpu_rq(i);
+		sd = *per_cpu_ptr(d.sd, i);
+
+		/* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */
+		if (rq->cpu_capacity_orig > READ_ONCE(d.rd->max_cpu_capacity))
+			WRITE_ONCE(d.rd->max_cpu_capacity, rq->cpu_capacity_orig);
+
+		cpu_attach_domain(sd, d.rd, i);
+	}
+	rcu_read_unlock();
+
+	if (has_asym)
+		static_branch_inc_cpuslocked(&sched_asym_cpucapacity);
+
+	if (rq && sched_debug_verbose) {
+		pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n",
+			cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
+	}
+
+	ret = 0;
+error:
+	__free_domain_allocs(&d, alloc_state, cpu_map);
+
+	return ret;
+}
+
+/* Current sched domains: */
+static cpumask_var_t			*doms_cur;
+
+/* Number of sched domains in 'doms_cur': */
+static int				ndoms_cur;
+
+/* Attributes of custom domains in 'doms_cur' */
+static struct sched_domain_attr		*dattr_cur;
+
+/*
+ * Special case: If a kmalloc() of a doms_cur partition (array of
+ * cpumask) fails, then fallback to a single sched domain,
+ * as determined by the single cpumask fallback_doms.
+ */
+static cpumask_var_t			fallback_doms;
+
+/*
+ * arch_update_cpu_topology lets virtualized architectures update the
+ * CPU core maps. It is supposed to return 1 if the topology changed
+ * or 0 if it stayed the same.
+ */
+int __weak arch_update_cpu_topology(void)
+{
+	return 0;
+}
+
+cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
+{
+	int i;
+	cpumask_var_t *doms;
+
+	doms = kmalloc_array(ndoms, sizeof(*doms), GFP_KERNEL);
+	if (!doms)
+		return NULL;
+	for (i = 0; i < ndoms; i++) {
+		if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
+			free_sched_domains(doms, i);
+			return NULL;
+		}
+	}
+	return doms;
+}
+
+void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
+{
+	unsigned int i;
+	for (i = 0; i < ndoms; i++)
+		free_cpumask_var(doms[i]);
+	kfree(doms);
+}
+
+/*
+ * Set up scheduler domains and groups.  For now this just excludes isolated
+ * CPUs, but could be used to exclude other special cases in the future.
+ */
+int sched_init_domains(const struct cpumask *cpu_map)
+{
+	int err;
+
+	zalloc_cpumask_var(&sched_domains_tmpmask, GFP_KERNEL);
+	zalloc_cpumask_var(&sched_domains_tmpmask2, GFP_KERNEL);
+	zalloc_cpumask_var(&fallback_doms, GFP_KERNEL);
+
+	arch_update_cpu_topology();
+	asym_cpu_capacity_scan();
+	ndoms_cur = 1;
+	doms_cur = alloc_sched_domains(ndoms_cur);
+	if (!doms_cur)
+		doms_cur = &fallback_doms;
+	cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_TYPE_DOMAIN));
+	err = build_sched_domains(doms_cur[0], NULL);
+
+	return err;
+}
+
+/*
+ * Detach sched domains from a group of CPUs specified in cpu_map
+ * These CPUs will now be attached to the NULL domain
+ */
+static void detach_destroy_domains(const struct cpumask *cpu_map)
+{
+	unsigned int cpu = cpumask_any(cpu_map);
+	int i;
+
+	if (rcu_access_pointer(per_cpu(sd_asym_cpucapacity, cpu)))
+		static_branch_dec_cpuslocked(&sched_asym_cpucapacity);
+
+	rcu_read_lock();
+	for_each_cpu(i, cpu_map)
+		cpu_attach_domain(NULL, &def_root_domain, i);
+	rcu_read_unlock();
+}
+
+/* handle null as "default" */
+static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
+			struct sched_domain_attr *new, int idx_new)
+{
+	struct sched_domain_attr tmp;
+
+	/* Fast path: */
+	if (!new && !cur)
+		return 1;
+
+	tmp = SD_ATTR_INIT;
+
+	return !memcmp(cur ? (cur + idx_cur) : &tmp,
+			new ? (new + idx_new) : &tmp,
+			sizeof(struct sched_domain_attr));
+}
+
+/*
+ * Partition sched domains as specified by the 'ndoms_new'
+ * cpumasks in the array doms_new[] of cpumasks. This compares
+ * doms_new[] to the current sched domain partitioning, doms_cur[].
+ * It destroys each deleted domain and builds each new domain.
+ *
+ * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
+ * The masks don't intersect (don't overlap.) We should setup one
+ * sched domain for each mask. CPUs not in any of the cpumasks will
+ * not be load balanced. If the same cpumask appears both in the
+ * current 'doms_cur' domains and in the new 'doms_new', we can leave
+ * it as it is.
+ *
+ * The passed in 'doms_new' should be allocated using
+ * alloc_sched_domains.  This routine takes ownership of it and will
+ * free_sched_domains it when done with it. If the caller failed the
+ * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
+ * and partition_sched_domains() will fallback to the single partition
+ * 'fallback_doms', it also forces the domains to be rebuilt.
+ *
+ * If doms_new == NULL it will be replaced with cpu_online_mask.
+ * ndoms_new == 0 is a special case for destroying existing domains,
+ * and it will not create the default domain.
+ *
+ * Call with hotplug lock and sched_domains_mutex held
+ */
+void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
+				    struct sched_domain_attr *dattr_new)
+{
+	bool __maybe_unused has_eas = false;
+	int i, j, n;
+	int new_topology;
+
+	lockdep_assert_held(&sched_domains_mutex);
+
+	/* Let the architecture update CPU core mappings: */
+	new_topology = arch_update_cpu_topology();
+	/* Trigger rebuilding CPU capacity asymmetry data */
+	if (new_topology)
+		asym_cpu_capacity_scan();
+
+	if (!doms_new) {
+		WARN_ON_ONCE(dattr_new);
+		n = 0;
+		doms_new = alloc_sched_domains(1);
+		if (doms_new) {
+			n = 1;
+			cpumask_and(doms_new[0], cpu_active_mask,
+				    housekeeping_cpumask(HK_TYPE_DOMAIN));
+		}
+	} else {
+		n = ndoms_new;
+	}
+
+	/* Destroy deleted domains: */
+	for (i = 0; i < ndoms_cur; i++) {
+		for (j = 0; j < n && !new_topology; j++) {
+			if (cpumask_equal(doms_cur[i], doms_new[j]) &&
+			    dattrs_equal(dattr_cur, i, dattr_new, j)) {
+				struct root_domain *rd;
+
+				/*
+				 * This domain won't be destroyed and as such
+				 * its dl_bw->total_bw needs to be cleared.  It
+				 * will be recomputed in function
+				 * update_tasks_root_domain().
+				 */
+				rd = cpu_rq(cpumask_any(doms_cur[i]))->rd;
+				dl_clear_root_domain(rd);
+				goto match1;
+			}
+		}
+		/* No match - a current sched domain not in new doms_new[] */
+		detach_destroy_domains(doms_cur[i]);
+match1:
+		;
+	}
+
+	n = ndoms_cur;
+	if (!doms_new) {
+		n = 0;
+		doms_new = &fallback_doms;
+		cpumask_and(doms_new[0], cpu_active_mask,
+			    housekeeping_cpumask(HK_TYPE_DOMAIN));
+	}
+
+	/* Build new domains: */
+	for (i = 0; i < ndoms_new; i++) {
+		for (j = 0; j < n && !new_topology; j++) {
+			if (cpumask_equal(doms_new[i], doms_cur[j]) &&
+			    dattrs_equal(dattr_new, i, dattr_cur, j))
+				goto match2;
+		}
+		/* No match - add a new doms_new */
+		build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
+match2:
+		;
+	}
+
+#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
+	/* Build perf. domains: */
+	for (i = 0; i < ndoms_new; i++) {
+		for (j = 0; j < n && !sched_energy_update; j++) {
+			if (cpumask_equal(doms_new[i], doms_cur[j]) &&
+			    cpu_rq(cpumask_first(doms_cur[j]))->rd->pd) {
+				has_eas = true;
+				goto match3;
+			}
+		}
+		/* No match - add perf. domains for a new rd */
+		has_eas |= build_perf_domains(doms_new[i]);
+match3:
+		;
+	}
+	sched_energy_set(has_eas);
+#endif
+
+	/* Remember the new sched domains: */
+	if (doms_cur != &fallback_doms)
+		free_sched_domains(doms_cur, ndoms_cur);
+
+	kfree(dattr_cur);
+	doms_cur = doms_new;
+	dattr_cur = dattr_new;
+	ndoms_cur = ndoms_new;
+
+	update_sched_domain_debugfs();
+}
+
+/*
+ * Call with hotplug lock held
+ */
+void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+			     struct sched_domain_attr *dattr_new)
+{
+	mutex_lock(&sched_domains_mutex);
+	partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
+	mutex_unlock(&sched_domains_mutex);
+}
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
new file mode 100644
index 000000000..133b74730
--- /dev/null
+++ b/kernel/sched/wait.c
@@ -0,0 +1,486 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic waiting primitives.
+ *
+ * (C) 2004 Nadia Yvette Chambers, Oracle
+ */
+
+void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *key)
+{
+	spin_lock_init(&wq_head->lock);
+	lockdep_set_class_and_name(&wq_head->lock, key, name);
+	INIT_LIST_HEAD(&wq_head->head);
+}
+
+EXPORT_SYMBOL(__init_waitqueue_head);
+
+void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
+{
+	unsigned long flags;
+
+	wq_entry->flags &= ~WQ_FLAG_EXCLUSIVE;
+	spin_lock_irqsave(&wq_head->lock, flags);
+	__add_wait_queue(wq_head, wq_entry);
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+}
+EXPORT_SYMBOL(add_wait_queue);
+
+void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
+{
+	unsigned long flags;
+
+	wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
+	spin_lock_irqsave(&wq_head->lock, flags);
+	__add_wait_queue_entry_tail(wq_head, wq_entry);
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+}
+EXPORT_SYMBOL(add_wait_queue_exclusive);
+
+void add_wait_queue_priority(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
+{
+	unsigned long flags;
+
+	wq_entry->flags |= WQ_FLAG_EXCLUSIVE | WQ_FLAG_PRIORITY;
+	spin_lock_irqsave(&wq_head->lock, flags);
+	__add_wait_queue(wq_head, wq_entry);
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+}
+EXPORT_SYMBOL_GPL(add_wait_queue_priority);
+
+void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&wq_head->lock, flags);
+	__remove_wait_queue(wq_head, wq_entry);
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+}
+EXPORT_SYMBOL(remove_wait_queue);
+
+/*
+ * Scan threshold to break wait queue walk.
+ * This allows a waker to take a break from holding the
+ * wait queue lock during the wait queue walk.
+ */
+#define WAITQUEUE_WALK_BREAK_CNT 64
+
+/*
+ * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
+ * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
+ * number) then we wake that number of exclusive tasks, and potentially all
+ * the non-exclusive tasks. Normally, exclusive tasks will be at the end of
+ * the list and any non-exclusive tasks will be woken first. A priority task
+ * may be at the head of the list, and can consume the event without any other
+ * tasks being woken.
+ *
+ * There are circumstances in which we can try to wake a task which has already
+ * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
+ * zero in this (rare) case, and we handle it by continuing to scan the queue.
+ */
+static int __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode,
+			int nr_exclusive, int wake_flags, void *key,
+			wait_queue_entry_t *bookmark)
+{
+	wait_queue_entry_t *curr, *next;
+	int cnt = 0;
+
+	lockdep_assert_held(&wq_head->lock);
+
+	if (bookmark && (bookmark->flags & WQ_FLAG_BOOKMARK)) {
+		curr = list_next_entry(bookmark, entry);
+
+		list_del(&bookmark->entry);
+		bookmark->flags = 0;
+	} else
+		curr = list_first_entry(&wq_head->head, wait_queue_entry_t, entry);
+
+	if (&curr->entry == &wq_head->head)
+		return nr_exclusive;
+
+	list_for_each_entry_safe_from(curr, next, &wq_head->head, entry) {
+		unsigned flags = curr->flags;
+		int ret;
+
+		if (flags & WQ_FLAG_BOOKMARK)
+			continue;
+
+		ret = curr->func(curr, mode, wake_flags, key);
+		if (ret < 0)
+			break;
+		if (ret && (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
+			break;
+
+		if (bookmark && (++cnt > WAITQUEUE_WALK_BREAK_CNT) &&
+				(&next->entry != &wq_head->head)) {
+			bookmark->flags = WQ_FLAG_BOOKMARK;
+			list_add_tail(&bookmark->entry, &next->entry);
+			break;
+		}
+	}
+
+	return nr_exclusive;
+}
+
+static int __wake_up_common_lock(struct wait_queue_head *wq_head, unsigned int mode,
+			int nr_exclusive, int wake_flags, void *key)
+{
+	unsigned long flags;
+	wait_queue_entry_t bookmark;
+	int remaining = nr_exclusive;
+
+	bookmark.flags = 0;
+	bookmark.private = NULL;
+	bookmark.func = NULL;
+	INIT_LIST_HEAD(&bookmark.entry);
+
+	do {
+		spin_lock_irqsave(&wq_head->lock, flags);
+		remaining = __wake_up_common(wq_head, mode, remaining,
+						wake_flags, key, &bookmark);
+		spin_unlock_irqrestore(&wq_head->lock, flags);
+	} while (bookmark.flags & WQ_FLAG_BOOKMARK);
+
+	return nr_exclusive - remaining;
+}
+
+/**
+ * __wake_up - wake up threads blocked on a waitqueue.
+ * @wq_head: the waitqueue
+ * @mode: which threads
+ * @nr_exclusive: how many wake-one or wake-many threads to wake up
+ * @key: is directly passed to the wakeup function
+ *
+ * If this function wakes up a task, it executes a full memory barrier
+ * before accessing the task state.  Returns the number of exclusive
+ * tasks that were awaken.
+ */
+int __wake_up(struct wait_queue_head *wq_head, unsigned int mode,
+	      int nr_exclusive, void *key)
+{
+	return __wake_up_common_lock(wq_head, mode, nr_exclusive, 0, key);
+}
+EXPORT_SYMBOL(__wake_up);
+
+/*
+ * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
+ */
+void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr)
+{
+	__wake_up_common(wq_head, mode, nr, 0, NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(__wake_up_locked);
+
+void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key)
+{
+	__wake_up_common(wq_head, mode, 1, 0, key, NULL);
+}
+EXPORT_SYMBOL_GPL(__wake_up_locked_key);
+
+void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head,
+		unsigned int mode, void *key, wait_queue_entry_t *bookmark)
+{
+	__wake_up_common(wq_head, mode, 1, 0, key, bookmark);
+}
+EXPORT_SYMBOL_GPL(__wake_up_locked_key_bookmark);
+
+/**
+ * __wake_up_sync_key - wake up threads blocked on a waitqueue.
+ * @wq_head: the waitqueue
+ * @mode: which threads
+ * @key: opaque value to be passed to wakeup targets
+ *
+ * The sync wakeup differs that the waker knows that it will schedule
+ * away soon, so while the target thread will be woken up, it will not
+ * be migrated to another CPU - ie. the two threads are 'synchronized'
+ * with each other. This can prevent needless bouncing between CPUs.
+ *
+ * On UP it can prevent extra preemption.
+ *
+ * If this function wakes up a task, it executes a full memory barrier before
+ * accessing the task state.
+ */
+void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode,
+			void *key)
+{
+	if (unlikely(!wq_head))
+		return;
+
+	__wake_up_common_lock(wq_head, mode, 1, WF_SYNC, key);
+}
+EXPORT_SYMBOL_GPL(__wake_up_sync_key);
+
+/**
+ * __wake_up_locked_sync_key - wake up a thread blocked on a locked waitqueue.
+ * @wq_head: the waitqueue
+ * @mode: which threads
+ * @key: opaque value to be passed to wakeup targets
+ *
+ * The sync wakeup differs in that the waker knows that it will schedule
+ * away soon, so while the target thread will be woken up, it will not
+ * be migrated to another CPU - ie. the two threads are 'synchronized'
+ * with each other. This can prevent needless bouncing between CPUs.
+ *
+ * On UP it can prevent extra preemption.
+ *
+ * If this function wakes up a task, it executes a full memory barrier before
+ * accessing the task state.
+ */
+void __wake_up_locked_sync_key(struct wait_queue_head *wq_head,
+			       unsigned int mode, void *key)
+{
+        __wake_up_common(wq_head, mode, 1, WF_SYNC, key, NULL);
+}
+EXPORT_SYMBOL_GPL(__wake_up_locked_sync_key);
+
+/*
+ * __wake_up_sync - see __wake_up_sync_key()
+ */
+void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode)
+{
+	__wake_up_sync_key(wq_head, mode, NULL);
+}
+EXPORT_SYMBOL_GPL(__wake_up_sync);	/* For internal use only */
+
+void __wake_up_pollfree(struct wait_queue_head *wq_head)
+{
+	__wake_up(wq_head, TASK_NORMAL, 0, poll_to_key(EPOLLHUP | POLLFREE));
+	/* POLLFREE must have cleared the queue. */
+	WARN_ON_ONCE(waitqueue_active(wq_head));
+}
+
+/*
+ * Note: we use "set_current_state()" _after_ the wait-queue add,
+ * because we need a memory barrier there on SMP, so that any
+ * wake-function that tests for the wait-queue being active
+ * will be guaranteed to see waitqueue addition _or_ subsequent
+ * tests in this thread will see the wakeup having taken place.
+ *
+ * The spin_unlock() itself is semi-permeable and only protects
+ * one way (it only protects stuff inside the critical region and
+ * stops them from bleeding out - it would still allow subsequent
+ * loads to move into the critical region).
+ */
+void
+prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
+{
+	unsigned long flags;
+
+	wq_entry->flags &= ~WQ_FLAG_EXCLUSIVE;
+	spin_lock_irqsave(&wq_head->lock, flags);
+	if (list_empty(&wq_entry->entry))
+		__add_wait_queue(wq_head, wq_entry);
+	set_current_state(state);
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+}
+EXPORT_SYMBOL(prepare_to_wait);
+
+/* Returns true if we are the first waiter in the queue, false otherwise. */
+bool
+prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
+{
+	unsigned long flags;
+	bool was_empty = false;
+
+	wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
+	spin_lock_irqsave(&wq_head->lock, flags);
+	if (list_empty(&wq_entry->entry)) {
+		was_empty = list_empty(&wq_head->head);
+		__add_wait_queue_entry_tail(wq_head, wq_entry);
+	}
+	set_current_state(state);
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+	return was_empty;
+}
+EXPORT_SYMBOL(prepare_to_wait_exclusive);
+
+void init_wait_entry(struct wait_queue_entry *wq_entry, int flags)
+{
+	wq_entry->flags = flags;
+	wq_entry->private = current;
+	wq_entry->func = autoremove_wake_function;
+	INIT_LIST_HEAD(&wq_entry->entry);
+}
+EXPORT_SYMBOL(init_wait_entry);
+
+long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
+{
+	unsigned long flags;
+	long ret = 0;
+
+	spin_lock_irqsave(&wq_head->lock, flags);
+	if (signal_pending_state(state, current)) {
+		/*
+		 * Exclusive waiter must not fail if it was selected by wakeup,
+		 * it should "consume" the condition we were waiting for.
+		 *
+		 * The caller will recheck the condition and return success if
+		 * we were already woken up, we can not miss the event because
+		 * wakeup locks/unlocks the same wq_head->lock.
+		 *
+		 * But we need to ensure that set-condition + wakeup after that
+		 * can't see us, it should wake up another exclusive waiter if
+		 * we fail.
+		 */
+		list_del_init(&wq_entry->entry);
+		ret = -ERESTARTSYS;
+	} else {
+		if (list_empty(&wq_entry->entry)) {
+			if (wq_entry->flags & WQ_FLAG_EXCLUSIVE)
+				__add_wait_queue_entry_tail(wq_head, wq_entry);
+			else
+				__add_wait_queue(wq_head, wq_entry);
+		}
+		set_current_state(state);
+	}
+	spin_unlock_irqrestore(&wq_head->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(prepare_to_wait_event);
+
+/*
+ * Note! These two wait functions are entered with the
+ * wait-queue lock held (and interrupts off in the _irq
+ * case), so there is no race with testing the wakeup
+ * condition in the caller before they add the wait
+ * entry to the wake queue.
+ */
+int do_wait_intr(wait_queue_head_t *wq, wait_queue_entry_t *wait)
+{
+	if (likely(list_empty(&wait->entry)))
+		__add_wait_queue_entry_tail(wq, wait);
+
+	set_current_state(TASK_INTERRUPTIBLE);
+	if (signal_pending(current))
+		return -ERESTARTSYS;
+
+	spin_unlock(&wq->lock);
+	schedule();
+	spin_lock(&wq->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(do_wait_intr);
+
+int do_wait_intr_irq(wait_queue_head_t *wq, wait_queue_entry_t *wait)
+{
+	if (likely(list_empty(&wait->entry)))
+		__add_wait_queue_entry_tail(wq, wait);
+
+	set_current_state(TASK_INTERRUPTIBLE);
+	if (signal_pending(current))
+		return -ERESTARTSYS;
+
+	spin_unlock_irq(&wq->lock);
+	schedule();
+	spin_lock_irq(&wq->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(do_wait_intr_irq);
+
+/**
+ * finish_wait - clean up after waiting in a queue
+ * @wq_head: waitqueue waited on
+ * @wq_entry: wait descriptor
+ *
+ * Sets current thread back to running state and removes
+ * the wait descriptor from the given waitqueue if still
+ * queued.
+ */
+void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
+{
+	unsigned long flags;
+
+	__set_current_state(TASK_RUNNING);
+	/*
+	 * We can check for list emptiness outside the lock
+	 * IFF:
+	 *  - we use the "careful" check that verifies both
+	 *    the next and prev pointers, so that there cannot
+	 *    be any half-pending updates in progress on other
+	 *    CPU's that we haven't seen yet (and that might
+	 *    still change the stack area.
+	 * and
+	 *  - all other users take the lock (ie we can only
+	 *    have _one_ other CPU that looks at or modifies
+	 *    the list).
+	 */
+	if (!list_empty_careful(&wq_entry->entry)) {
+		spin_lock_irqsave(&wq_head->lock, flags);
+		list_del_init(&wq_entry->entry);
+		spin_unlock_irqrestore(&wq_head->lock, flags);
+	}
+}
+EXPORT_SYMBOL(finish_wait);
+
+int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key)
+{
+	int ret = default_wake_function(wq_entry, mode, sync, key);
+
+	if (ret)
+		list_del_init_careful(&wq_entry->entry);
+
+	return ret;
+}
+EXPORT_SYMBOL(autoremove_wake_function);
+
+static inline bool is_kthread_should_stop(void)
+{
+	return (current->flags & PF_KTHREAD) && kthread_should_stop();
+}
+
+/*
+ * DEFINE_WAIT_FUNC(wait, woken_wake_func);
+ *
+ * add_wait_queue(&wq_head, &wait);
+ * for (;;) {
+ *     if (condition)
+ *         break;
+ *
+ *     // in wait_woken()			// in woken_wake_function()
+ *
+ *     p->state = mode;				wq_entry->flags |= WQ_FLAG_WOKEN;
+ *     smp_mb(); // A				try_to_wake_up():
+ *     if (!(wq_entry->flags & WQ_FLAG_WOKEN))	   <full barrier>
+ *         schedule()				   if (p->state & mode)
+ *     p->state = TASK_RUNNING;			      p->state = TASK_RUNNING;
+ *     wq_entry->flags &= ~WQ_FLAG_WOKEN;	~~~~~~~~~~~~~~~~~~
+ *     smp_mb(); // B				condition = true;
+ * }						smp_mb(); // C
+ * remove_wait_queue(&wq_head, &wait);		wq_entry->flags |= WQ_FLAG_WOKEN;
+ */
+long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout)
+{
+	/*
+	 * The below executes an smp_mb(), which matches with the full barrier
+	 * executed by the try_to_wake_up() in woken_wake_function() such that
+	 * either we see the store to wq_entry->flags in woken_wake_function()
+	 * or woken_wake_function() sees our store to current->state.
+	 */
+	set_current_state(mode); /* A */
+	if (!(wq_entry->flags & WQ_FLAG_WOKEN) && !is_kthread_should_stop())
+		timeout = schedule_timeout(timeout);
+	__set_current_state(TASK_RUNNING);
+
+	/*
+	 * The below executes an smp_mb(), which matches with the smp_mb() (C)
+	 * in woken_wake_function() such that either we see the wait condition
+	 * being true or the store to wq_entry->flags in woken_wake_function()
+	 * follows ours in the coherence order.
+	 */
+	smp_store_mb(wq_entry->flags, wq_entry->flags & ~WQ_FLAG_WOKEN); /* B */
+
+	return timeout;
+}
+EXPORT_SYMBOL(wait_woken);
+
+int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key)
+{
+	/* Pairs with the smp_store_mb() in wait_woken(). */
+	smp_mb(); /* C */
+	wq_entry->flags |= WQ_FLAG_WOKEN;
+
+	return default_wake_function(wq_entry, mode, sync, key);
+}
+EXPORT_SYMBOL(woken_wake_function);
diff --git a/kernel/sched/wait_bit.c b/kernel/sched/wait_bit.c
new file mode 100644
index 000000000..0b1cd985d
--- /dev/null
+++ b/kernel/sched/wait_bit.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * The implementation of the wait_bit*() and related waiting APIs:
+ */
+
+#define WAIT_TABLE_BITS 8
+#define WAIT_TABLE_SIZE (1 << WAIT_TABLE_BITS)
+
+static wait_queue_head_t bit_wait_table[WAIT_TABLE_SIZE] __cacheline_aligned;
+
+wait_queue_head_t *bit_waitqueue(void *word, int bit)
+{
+	const int shift = BITS_PER_LONG == 32 ? 5 : 6;
+	unsigned long val = (unsigned long)word << shift | bit;
+
+	return bit_wait_table + hash_long(val, WAIT_TABLE_BITS);
+}
+EXPORT_SYMBOL(bit_waitqueue);
+
+int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *arg)
+{
+	struct wait_bit_key *key = arg;
+	struct wait_bit_queue_entry *wait_bit = container_of(wq_entry, struct wait_bit_queue_entry, wq_entry);
+
+	if (wait_bit->key.flags != key->flags ||
+			wait_bit->key.bit_nr != key->bit_nr ||
+			test_bit(key->bit_nr, key->flags))
+		return 0;
+
+	return autoremove_wake_function(wq_entry, mode, sync, key);
+}
+EXPORT_SYMBOL(wake_bit_function);
+
+/*
+ * To allow interruptible waiting and asynchronous (i.e. nonblocking)
+ * waiting, the actions of __wait_on_bit() and __wait_on_bit_lock() are
+ * permitted return codes. Nonzero return codes halt waiting and return.
+ */
+int __sched
+__wait_on_bit(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry,
+	      wait_bit_action_f *action, unsigned mode)
+{
+	int ret = 0;
+
+	do {
+		prepare_to_wait(wq_head, &wbq_entry->wq_entry, mode);
+		if (test_bit(wbq_entry->key.bit_nr, wbq_entry->key.flags))
+			ret = (*action)(&wbq_entry->key, mode);
+	} while (test_bit_acquire(wbq_entry->key.bit_nr, wbq_entry->key.flags) && !ret);
+
+	finish_wait(wq_head, &wbq_entry->wq_entry);
+
+	return ret;
+}
+EXPORT_SYMBOL(__wait_on_bit);
+
+int __sched out_of_line_wait_on_bit(void *word, int bit,
+				    wait_bit_action_f *action, unsigned mode)
+{
+	struct wait_queue_head *wq_head = bit_waitqueue(word, bit);
+	DEFINE_WAIT_BIT(wq_entry, word, bit);
+
+	return __wait_on_bit(wq_head, &wq_entry, action, mode);
+}
+EXPORT_SYMBOL(out_of_line_wait_on_bit);
+
+int __sched out_of_line_wait_on_bit_timeout(
+	void *word, int bit, wait_bit_action_f *action,
+	unsigned mode, unsigned long timeout)
+{
+	struct wait_queue_head *wq_head = bit_waitqueue(word, bit);
+	DEFINE_WAIT_BIT(wq_entry, word, bit);
+
+	wq_entry.key.timeout = jiffies + timeout;
+
+	return __wait_on_bit(wq_head, &wq_entry, action, mode);
+}
+EXPORT_SYMBOL_GPL(out_of_line_wait_on_bit_timeout);
+
+int __sched
+__wait_on_bit_lock(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry,
+			wait_bit_action_f *action, unsigned mode)
+{
+	int ret = 0;
+
+	for (;;) {
+		prepare_to_wait_exclusive(wq_head, &wbq_entry->wq_entry, mode);
+		if (test_bit(wbq_entry->key.bit_nr, wbq_entry->key.flags)) {
+			ret = action(&wbq_entry->key, mode);
+			/*
+			 * See the comment in prepare_to_wait_event().
+			 * finish_wait() does not necessarily takes wwq_head->lock,
+			 * but test_and_set_bit() implies mb() which pairs with
+			 * smp_mb__after_atomic() before wake_up_page().
+			 */
+			if (ret)
+				finish_wait(wq_head, &wbq_entry->wq_entry);
+		}
+		if (!test_and_set_bit(wbq_entry->key.bit_nr, wbq_entry->key.flags)) {
+			if (!ret)
+				finish_wait(wq_head, &wbq_entry->wq_entry);
+			return 0;
+		} else if (ret) {
+			return ret;
+		}
+	}
+}
+EXPORT_SYMBOL(__wait_on_bit_lock);
+
+int __sched out_of_line_wait_on_bit_lock(void *word, int bit,
+					 wait_bit_action_f *action, unsigned mode)
+{
+	struct wait_queue_head *wq_head = bit_waitqueue(word, bit);
+	DEFINE_WAIT_BIT(wq_entry, word, bit);
+
+	return __wait_on_bit_lock(wq_head, &wq_entry, action, mode);
+}
+EXPORT_SYMBOL(out_of_line_wait_on_bit_lock);
+
+void __wake_up_bit(struct wait_queue_head *wq_head, void *word, int bit)
+{
+	struct wait_bit_key key = __WAIT_BIT_KEY_INITIALIZER(word, bit);
+
+	if (waitqueue_active(wq_head))
+		__wake_up(wq_head, TASK_NORMAL, 1, &key);
+}
+EXPORT_SYMBOL(__wake_up_bit);
+
+/**
+ * wake_up_bit - wake up a waiter on a bit
+ * @word: the word being waited on, a kernel virtual address
+ * @bit: the bit of the word being waited on
+ *
+ * There is a standard hashed waitqueue table for generic use. This
+ * is the part of the hashtable's accessor API that wakes up waiters
+ * on a bit. For instance, if one were to have waiters on a bitflag,
+ * one would call wake_up_bit() after clearing the bit.
+ *
+ * In order for this to function properly, as it uses waitqueue_active()
+ * internally, some kind of memory barrier must be done prior to calling
+ * this. Typically, this will be smp_mb__after_atomic(), but in some
+ * cases where bitflags are manipulated non-atomically under a lock, one
+ * may need to use a less regular barrier, such fs/inode.c's smp_mb(),
+ * because spin_unlock() does not guarantee a memory barrier.
+ */
+void wake_up_bit(void *word, int bit)
+{
+	__wake_up_bit(bit_waitqueue(word, bit), word, bit);
+}
+EXPORT_SYMBOL(wake_up_bit);
+
+wait_queue_head_t *__var_waitqueue(void *p)
+{
+	return bit_wait_table + hash_ptr(p, WAIT_TABLE_BITS);
+}
+EXPORT_SYMBOL(__var_waitqueue);
+
+static int
+var_wake_function(struct wait_queue_entry *wq_entry, unsigned int mode,
+		  int sync, void *arg)
+{
+	struct wait_bit_key *key = arg;
+	struct wait_bit_queue_entry *wbq_entry =
+		container_of(wq_entry, struct wait_bit_queue_entry, wq_entry);
+
+	if (wbq_entry->key.flags != key->flags ||
+	    wbq_entry->key.bit_nr != key->bit_nr)
+		return 0;
+
+	return autoremove_wake_function(wq_entry, mode, sync, key);
+}
+
+void init_wait_var_entry(struct wait_bit_queue_entry *wbq_entry, void *var, int flags)
+{
+	*wbq_entry = (struct wait_bit_queue_entry){
+		.key = {
+			.flags	= (var),
+			.bit_nr = -1,
+		},
+		.wq_entry = {
+			.flags	 = flags,
+			.private = current,
+			.func	 = var_wake_function,
+			.entry	 = LIST_HEAD_INIT(wbq_entry->wq_entry.entry),
+		},
+	};
+}
+EXPORT_SYMBOL(init_wait_var_entry);
+
+void wake_up_var(void *var)
+{
+	__wake_up_bit(__var_waitqueue(var), var, -1);
+}
+EXPORT_SYMBOL(wake_up_var);
+
+__sched int bit_wait(struct wait_bit_key *word, int mode)
+{
+	schedule();
+	if (signal_pending_state(mode, current))
+		return -EINTR;
+
+	return 0;
+}
+EXPORT_SYMBOL(bit_wait);
+
+__sched int bit_wait_io(struct wait_bit_key *word, int mode)
+{
+	io_schedule();
+	if (signal_pending_state(mode, current))
+		return -EINTR;
+
+	return 0;
+}
+EXPORT_SYMBOL(bit_wait_io);
+
+__sched int bit_wait_timeout(struct wait_bit_key *word, int mode)
+{
+	unsigned long now = READ_ONCE(jiffies);
+
+	if (time_after_eq(now, word->timeout))
+		return -EAGAIN;
+	schedule_timeout(word->timeout - now);
+	if (signal_pending_state(mode, current))
+		return -EINTR;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(bit_wait_timeout);
+
+__sched int bit_wait_io_timeout(struct wait_bit_key *word, int mode)
+{
+	unsigned long now = READ_ONCE(jiffies);
+
+	if (time_after_eq(now, word->timeout))
+		return -EAGAIN;
+	io_schedule_timeout(word->timeout - now);
+	if (signal_pending_state(mode, current))
+		return -EINTR;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(bit_wait_io_timeout);
+
+void __init wait_bit_init(void)
+{
+	int i;
+
+	for (i = 0; i < WAIT_TABLE_SIZE; i++)
+		init_waitqueue_head(bit_wait_table + i);
+}
diff --git a/kernel/scs.c b/kernel/scs.c
new file mode 100644
index 000000000..b7e1b096d
--- /dev/null
+++ b/kernel/scs.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Shadow Call Stack support.
+ *
+ * Copyright (C) 2019 Google LLC
+ */
+
+#include <linux/cpuhotplug.h>
+#include <linux/kasan.h>
+#include <linux/mm.h>
+#include <linux/scs.h>
+#include <linux/vmalloc.h>
+#include <linux/vmstat.h>
+
+static void __scs_account(void *s, int account)
+{
+	struct page *scs_page = vmalloc_to_page(s);
+
+	mod_node_page_state(page_pgdat(scs_page), NR_KERNEL_SCS_KB,
+			    account * (SCS_SIZE / SZ_1K));
+}
+
+/* Matches NR_CACHED_STACKS for VMAP_STACK */
+#define NR_CACHED_SCS 2
+static DEFINE_PER_CPU(void *, scs_cache[NR_CACHED_SCS]);
+
+static void *__scs_alloc(int node)
+{
+	int i;
+	void *s;
+
+	for (i = 0; i < NR_CACHED_SCS; i++) {
+		s = this_cpu_xchg(scs_cache[i], NULL);
+		if (s) {
+			s = kasan_unpoison_vmalloc(s, SCS_SIZE,
+						   KASAN_VMALLOC_PROT_NORMAL);
+			memset(s, 0, SCS_SIZE);
+			goto out;
+		}
+	}
+
+	s = __vmalloc_node_range(SCS_SIZE, 1, VMALLOC_START, VMALLOC_END,
+				    GFP_SCS, PAGE_KERNEL, 0, node,
+				    __builtin_return_address(0));
+
+out:
+	return kasan_reset_tag(s);
+}
+
+void *scs_alloc(int node)
+{
+	void *s;
+
+	s = __scs_alloc(node);
+	if (!s)
+		return NULL;
+
+	*__scs_magic(s) = SCS_END_MAGIC;
+
+	/*
+	 * Poison the allocation to catch unintentional accesses to
+	 * the shadow stack when KASAN is enabled.
+	 */
+	kasan_poison_vmalloc(s, SCS_SIZE);
+	__scs_account(s, 1);
+	return s;
+}
+
+void scs_free(void *s)
+{
+	int i;
+
+	__scs_account(s, -1);
+
+	/*
+	 * We cannot sleep as this can be called in interrupt context,
+	 * so use this_cpu_cmpxchg to update the cache, and vfree_atomic
+	 * to free the stack.
+	 */
+
+	for (i = 0; i < NR_CACHED_SCS; i++)
+		if (this_cpu_cmpxchg(scs_cache[i], 0, s) == NULL)
+			return;
+
+	kasan_unpoison_vmalloc(s, SCS_SIZE, KASAN_VMALLOC_PROT_NORMAL);
+	vfree_atomic(s);
+}
+
+static int scs_cleanup(unsigned int cpu)
+{
+	int i;
+	void **cache = per_cpu_ptr(scs_cache, cpu);
+
+	for (i = 0; i < NR_CACHED_SCS; i++) {
+		vfree(cache[i]);
+		cache[i] = NULL;
+	}
+
+	return 0;
+}
+
+void __init scs_init(void)
+{
+	cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "scs:scs_cache", NULL,
+			  scs_cleanup);
+}
+
+int scs_prepare(struct task_struct *tsk, int node)
+{
+	void *s = scs_alloc(node);
+
+	if (!s)
+		return -ENOMEM;
+
+	task_scs(tsk) = task_scs_sp(tsk) = s;
+	return 0;
+}
+
+static void scs_check_usage(struct task_struct *tsk)
+{
+	static unsigned long highest;
+
+	unsigned long *p, prev, curr = highest, used = 0;
+
+	if (!IS_ENABLED(CONFIG_DEBUG_STACK_USAGE))
+		return;
+
+	for (p = task_scs(tsk); p < __scs_magic(tsk); ++p) {
+		if (!READ_ONCE_NOCHECK(*p))
+			break;
+		used += sizeof(*p);
+	}
+
+	while (used > curr) {
+		prev = cmpxchg_relaxed(&highest, curr, used);
+
+		if (prev == curr) {
+			pr_info("%s (%d): highest shadow stack usage: %lu bytes\n",
+				tsk->comm, task_pid_nr(tsk), used);
+			break;
+		}
+
+		curr = prev;
+	}
+}
+
+void scs_release(struct task_struct *tsk)
+{
+	void *s = task_scs(tsk);
+
+	if (!s)
+		return;
+
+	WARN(task_scs_end_corrupted(tsk),
+	     "corrupted shadow stack detected when freeing task\n");
+	scs_check_usage(tsk);
+	scs_free(s);
+}
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
new file mode 100644
index 000000000..e9852d1b4
--- /dev/null
+++ b/kernel/seccomp.c
@@ -0,0 +1,2464 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/kernel/seccomp.c
+ *
+ * Copyright 2004-2005  Andrea Arcangeli <andrea@cpushare.com>
+ *
+ * Copyright (C) 2012 Google, Inc.
+ * Will Drewry <wad@chromium.org>
+ *
+ * This defines a simple but solid secure-computing facility.
+ *
+ * Mode 1 uses a fixed list of allowed system calls.
+ * Mode 2 allows user-defined system call filters in the form
+ *        of Berkeley Packet Filters/Linux Socket Filters.
+ */
+#define pr_fmt(fmt) "seccomp: " fmt
+
+#include <linux/refcount.h>
+#include <linux/audit.h>
+#include <linux/compat.h>
+#include <linux/coredump.h>
+#include <linux/kmemleak.h>
+#include <linux/nospec.h>
+#include <linux/prctl.h>
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <linux/seccomp.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/sysctl.h>
+
+/* Not exposed in headers: strictly internal use only. */
+#define SECCOMP_MODE_DEAD	(SECCOMP_MODE_FILTER + 1)
+
+#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
+#include <asm/syscall.h>
+#endif
+
+#ifdef CONFIG_SECCOMP_FILTER
+#include <linux/file.h>
+#include <linux/filter.h>
+#include <linux/pid.h>
+#include <linux/ptrace.h>
+#include <linux/capability.h>
+#include <linux/uaccess.h>
+#include <linux/anon_inodes.h>
+#include <linux/lockdep.h>
+
+/*
+ * When SECCOMP_IOCTL_NOTIF_ID_VALID was first introduced, it had the
+ * wrong direction flag in the ioctl number. This is the broken one,
+ * which the kernel needs to keep supporting until all userspaces stop
+ * using the wrong command number.
+ */
+#define SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR	SECCOMP_IOR(2, __u64)
+
+enum notify_state {
+	SECCOMP_NOTIFY_INIT,
+	SECCOMP_NOTIFY_SENT,
+	SECCOMP_NOTIFY_REPLIED,
+};
+
+struct seccomp_knotif {
+	/* The struct pid of the task whose filter triggered the notification */
+	struct task_struct *task;
+
+	/* The "cookie" for this request; this is unique for this filter. */
+	u64 id;
+
+	/*
+	 * The seccomp data. This pointer is valid the entire time this
+	 * notification is active, since it comes from __seccomp_filter which
+	 * eclipses the entire lifecycle here.
+	 */
+	const struct seccomp_data *data;
+
+	/*
+	 * Notification states. When SECCOMP_RET_USER_NOTIF is returned, a
+	 * struct seccomp_knotif is created and starts out in INIT. Once the
+	 * handler reads the notification off of an FD, it transitions to SENT.
+	 * If a signal is received the state transitions back to INIT and
+	 * another message is sent. When the userspace handler replies, state
+	 * transitions to REPLIED.
+	 */
+	enum notify_state state;
+
+	/* The return values, only valid when in SECCOMP_NOTIFY_REPLIED */
+	int error;
+	long val;
+	u32 flags;
+
+	/*
+	 * Signals when this has changed states, such as the listener
+	 * dying, a new seccomp addfd message, or changing to REPLIED
+	 */
+	struct completion ready;
+
+	struct list_head list;
+
+	/* outstanding addfd requests */
+	struct list_head addfd;
+};
+
+/**
+ * struct seccomp_kaddfd - container for seccomp_addfd ioctl messages
+ *
+ * @file: A reference to the file to install in the other task
+ * @fd: The fd number to install it at. If the fd number is -1, it means the
+ *      installing process should allocate the fd as normal.
+ * @flags: The flags for the new file descriptor. At the moment, only O_CLOEXEC
+ *         is allowed.
+ * @ioctl_flags: The flags used for the seccomp_addfd ioctl.
+ * @ret: The return value of the installing process. It is set to the fd num
+ *       upon success (>= 0).
+ * @completion: Indicates that the installing process has completed fd
+ *              installation, or gone away (either due to successful
+ *              reply, or signal)
+ *
+ */
+struct seccomp_kaddfd {
+	struct file *file;
+	int fd;
+	unsigned int flags;
+	__u32 ioctl_flags;
+
+	union {
+		bool setfd;
+		/* To only be set on reply */
+		int ret;
+	};
+	struct completion completion;
+	struct list_head list;
+};
+
+/**
+ * struct notification - container for seccomp userspace notifications. Since
+ * most seccomp filters will not have notification listeners attached and this
+ * structure is fairly large, we store the notification-specific stuff in a
+ * separate structure.
+ *
+ * @request: A semaphore that users of this notification can wait on for
+ *           changes. Actual reads and writes are still controlled with
+ *           filter->notify_lock.
+ * @next_id: The id of the next request.
+ * @notifications: A list of struct seccomp_knotif elements.
+ */
+struct notification {
+	struct semaphore request;
+	u64 next_id;
+	struct list_head notifications;
+};
+
+#ifdef SECCOMP_ARCH_NATIVE
+/**
+ * struct action_cache - per-filter cache of seccomp actions per
+ * arch/syscall pair
+ *
+ * @allow_native: A bitmap where each bit represents whether the
+ *		  filter will always allow the syscall, for the
+ *		  native architecture.
+ * @allow_compat: A bitmap where each bit represents whether the
+ *		  filter will always allow the syscall, for the
+ *		  compat architecture.
+ */
+struct action_cache {
+	DECLARE_BITMAP(allow_native, SECCOMP_ARCH_NATIVE_NR);
+#ifdef SECCOMP_ARCH_COMPAT
+	DECLARE_BITMAP(allow_compat, SECCOMP_ARCH_COMPAT_NR);
+#endif
+};
+#else
+struct action_cache { };
+
+static inline bool seccomp_cache_check_allow(const struct seccomp_filter *sfilter,
+					     const struct seccomp_data *sd)
+{
+	return false;
+}
+
+static inline void seccomp_cache_prepare(struct seccomp_filter *sfilter)
+{
+}
+#endif /* SECCOMP_ARCH_NATIVE */
+
+/**
+ * struct seccomp_filter - container for seccomp BPF programs
+ *
+ * @refs: Reference count to manage the object lifetime.
+ *	  A filter's reference count is incremented for each directly
+ *	  attached task, once for the dependent filter, and if
+ *	  requested for the user notifier. When @refs reaches zero,
+ *	  the filter can be freed.
+ * @users: A filter's @users count is incremented for each directly
+ *         attached task (filter installation, fork(), thread_sync),
+ *	   and once for the dependent filter (tracked in filter->prev).
+ *	   When it reaches zero it indicates that no direct or indirect
+ *	   users of that filter exist. No new tasks can get associated with
+ *	   this filter after reaching 0. The @users count is always smaller
+ *	   or equal to @refs. Hence, reaching 0 for @users does not mean
+ *	   the filter can be freed.
+ * @cache: cache of arch/syscall mappings to actions
+ * @log: true if all actions except for SECCOMP_RET_ALLOW should be logged
+ * @wait_killable_recv: Put notifying process in killable state once the
+ *			notification is received by the userspace listener.
+ * @prev: points to a previously installed, or inherited, filter
+ * @prog: the BPF program to evaluate
+ * @notif: the struct that holds all notification related information
+ * @notify_lock: A lock for all notification-related accesses.
+ * @wqh: A wait queue for poll if a notifier is in use.
+ *
+ * seccomp_filter objects are organized in a tree linked via the @prev
+ * pointer.  For any task, it appears to be a singly-linked list starting
+ * with current->seccomp.filter, the most recently attached or inherited filter.
+ * However, multiple filters may share a @prev node, by way of fork(), which
+ * results in a unidirectional tree existing in memory.  This is similar to
+ * how namespaces work.
+ *
+ * seccomp_filter objects should never be modified after being attached
+ * to a task_struct (other than @refs).
+ */
+struct seccomp_filter {
+	refcount_t refs;
+	refcount_t users;
+	bool log;
+	bool wait_killable_recv;
+	struct action_cache cache;
+	struct seccomp_filter *prev;
+	struct bpf_prog *prog;
+	struct notification *notif;
+	struct mutex notify_lock;
+	wait_queue_head_t wqh;
+};
+
+/* Limit any path through the tree to 256KB worth of instructions. */
+#define MAX_INSNS_PER_PATH ((1 << 18) / sizeof(struct sock_filter))
+
+/*
+ * Endianness is explicitly ignored and left for BPF program authors to manage
+ * as per the specific architecture.
+ */
+static void populate_seccomp_data(struct seccomp_data *sd)
+{
+	/*
+	 * Instead of using current_pt_reg(), we're already doing the work
+	 * to safely fetch "current", so just use "task" everywhere below.
+	 */
+	struct task_struct *task = current;
+	struct pt_regs *regs = task_pt_regs(task);
+	unsigned long args[6];
+
+	sd->nr = syscall_get_nr(task, regs);
+	sd->arch = syscall_get_arch(task);
+	syscall_get_arguments(task, regs, args);
+	sd->args[0] = args[0];
+	sd->args[1] = args[1];
+	sd->args[2] = args[2];
+	sd->args[3] = args[3];
+	sd->args[4] = args[4];
+	sd->args[5] = args[5];
+	sd->instruction_pointer = KSTK_EIP(task);
+}
+
+/**
+ *	seccomp_check_filter - verify seccomp filter code
+ *	@filter: filter to verify
+ *	@flen: length of filter
+ *
+ * Takes a previously checked filter (by bpf_check_classic) and
+ * redirects all filter code that loads struct sk_buff data
+ * and related data through seccomp_bpf_load.  It also
+ * enforces length and alignment checking of those loads.
+ *
+ * Returns 0 if the rule set is legal or -EINVAL if not.
+ */
+static int seccomp_check_filter(struct sock_filter *filter, unsigned int flen)
+{
+	int pc;
+	for (pc = 0; pc < flen; pc++) {
+		struct sock_filter *ftest = &filter[pc];
+		u16 code = ftest->code;
+		u32 k = ftest->k;
+
+		switch (code) {
+		case BPF_LD | BPF_W | BPF_ABS:
+			ftest->code = BPF_LDX | BPF_W | BPF_ABS;
+			/* 32-bit aligned and not out of bounds. */
+			if (k >= sizeof(struct seccomp_data) || k & 3)
+				return -EINVAL;
+			continue;
+		case BPF_LD | BPF_W | BPF_LEN:
+			ftest->code = BPF_LD | BPF_IMM;
+			ftest->k = sizeof(struct seccomp_data);
+			continue;
+		case BPF_LDX | BPF_W | BPF_LEN:
+			ftest->code = BPF_LDX | BPF_IMM;
+			ftest->k = sizeof(struct seccomp_data);
+			continue;
+		/* Explicitly include allowed calls. */
+		case BPF_RET | BPF_K:
+		case BPF_RET | BPF_A:
+		case BPF_ALU | BPF_ADD | BPF_K:
+		case BPF_ALU | BPF_ADD | BPF_X:
+		case BPF_ALU | BPF_SUB | BPF_K:
+		case BPF_ALU | BPF_SUB | BPF_X:
+		case BPF_ALU | BPF_MUL | BPF_K:
+		case BPF_ALU | BPF_MUL | BPF_X:
+		case BPF_ALU | BPF_DIV | BPF_K:
+		case BPF_ALU | BPF_DIV | BPF_X:
+		case BPF_ALU | BPF_AND | BPF_K:
+		case BPF_ALU | BPF_AND | BPF_X:
+		case BPF_ALU | BPF_OR | BPF_K:
+		case BPF_ALU | BPF_OR | BPF_X:
+		case BPF_ALU | BPF_XOR | BPF_K:
+		case BPF_ALU | BPF_XOR | BPF_X:
+		case BPF_ALU | BPF_LSH | BPF_K:
+		case BPF_ALU | BPF_LSH | BPF_X:
+		case BPF_ALU | BPF_RSH | BPF_K:
+		case BPF_ALU | BPF_RSH | BPF_X:
+		case BPF_ALU | BPF_NEG:
+		case BPF_LD | BPF_IMM:
+		case BPF_LDX | BPF_IMM:
+		case BPF_MISC | BPF_TAX:
+		case BPF_MISC | BPF_TXA:
+		case BPF_LD | BPF_MEM:
+		case BPF_LDX | BPF_MEM:
+		case BPF_ST:
+		case BPF_STX:
+		case BPF_JMP | BPF_JA:
+		case BPF_JMP | BPF_JEQ | BPF_K:
+		case BPF_JMP | BPF_JEQ | BPF_X:
+		case BPF_JMP | BPF_JGE | BPF_K:
+		case BPF_JMP | BPF_JGE | BPF_X:
+		case BPF_JMP | BPF_JGT | BPF_K:
+		case BPF_JMP | BPF_JGT | BPF_X:
+		case BPF_JMP | BPF_JSET | BPF_K:
+		case BPF_JMP | BPF_JSET | BPF_X:
+			continue;
+		default:
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+#ifdef SECCOMP_ARCH_NATIVE
+static inline bool seccomp_cache_check_allow_bitmap(const void *bitmap,
+						    size_t bitmap_size,
+						    int syscall_nr)
+{
+	if (unlikely(syscall_nr < 0 || syscall_nr >= bitmap_size))
+		return false;
+	syscall_nr = array_index_nospec(syscall_nr, bitmap_size);
+
+	return test_bit(syscall_nr, bitmap);
+}
+
+/**
+ * seccomp_cache_check_allow - lookup seccomp cache
+ * @sfilter: The seccomp filter
+ * @sd: The seccomp data to lookup the cache with
+ *
+ * Returns true if the seccomp_data is cached and allowed.
+ */
+static inline bool seccomp_cache_check_allow(const struct seccomp_filter *sfilter,
+					     const struct seccomp_data *sd)
+{
+	int syscall_nr = sd->nr;
+	const struct action_cache *cache = &sfilter->cache;
+
+#ifndef SECCOMP_ARCH_COMPAT
+	/* A native-only architecture doesn't need to check sd->arch. */
+	return seccomp_cache_check_allow_bitmap(cache->allow_native,
+						SECCOMP_ARCH_NATIVE_NR,
+						syscall_nr);
+#else
+	if (likely(sd->arch == SECCOMP_ARCH_NATIVE))
+		return seccomp_cache_check_allow_bitmap(cache->allow_native,
+							SECCOMP_ARCH_NATIVE_NR,
+							syscall_nr);
+	if (likely(sd->arch == SECCOMP_ARCH_COMPAT))
+		return seccomp_cache_check_allow_bitmap(cache->allow_compat,
+							SECCOMP_ARCH_COMPAT_NR,
+							syscall_nr);
+#endif /* SECCOMP_ARCH_COMPAT */
+
+	WARN_ON_ONCE(true);
+	return false;
+}
+#endif /* SECCOMP_ARCH_NATIVE */
+
+/**
+ * seccomp_run_filters - evaluates all seccomp filters against @sd
+ * @sd: optional seccomp data to be passed to filters
+ * @match: stores struct seccomp_filter that resulted in the return value,
+ *         unless filter returned SECCOMP_RET_ALLOW, in which case it will
+ *         be unchanged.
+ *
+ * Returns valid seccomp BPF response codes.
+ */
+#define ACTION_ONLY(ret) ((s32)((ret) & (SECCOMP_RET_ACTION_FULL)))
+static u32 seccomp_run_filters(const struct seccomp_data *sd,
+			       struct seccomp_filter **match)
+{
+	u32 ret = SECCOMP_RET_ALLOW;
+	/* Make sure cross-thread synced filter points somewhere sane. */
+	struct seccomp_filter *f =
+			READ_ONCE(current->seccomp.filter);
+
+	/* Ensure unexpected behavior doesn't result in failing open. */
+	if (WARN_ON(f == NULL))
+		return SECCOMP_RET_KILL_PROCESS;
+
+	if (seccomp_cache_check_allow(f, sd))
+		return SECCOMP_RET_ALLOW;
+
+	/*
+	 * All filters in the list are evaluated and the lowest BPF return
+	 * value always takes priority (ignoring the DATA).
+	 */
+	for (; f; f = f->prev) {
+		u32 cur_ret = bpf_prog_run_pin_on_cpu(f->prog, sd);
+
+		if (ACTION_ONLY(cur_ret) < ACTION_ONLY(ret)) {
+			ret = cur_ret;
+			*match = f;
+		}
+	}
+	return ret;
+}
+#endif /* CONFIG_SECCOMP_FILTER */
+
+static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode)
+{
+	assert_spin_locked(&current->sighand->siglock);
+
+	if (current->seccomp.mode && current->seccomp.mode != seccomp_mode)
+		return false;
+
+	return true;
+}
+
+void __weak arch_seccomp_spec_mitigate(struct task_struct *task) { }
+
+static inline void seccomp_assign_mode(struct task_struct *task,
+				       unsigned long seccomp_mode,
+				       unsigned long flags)
+{
+	assert_spin_locked(&task->sighand->siglock);
+
+	task->seccomp.mode = seccomp_mode;
+	/*
+	 * Make sure SYSCALL_WORK_SECCOMP cannot be set before the mode (and
+	 * filter) is set.
+	 */
+	smp_mb__before_atomic();
+	/* Assume default seccomp processes want spec flaw mitigation. */
+	if ((flags & SECCOMP_FILTER_FLAG_SPEC_ALLOW) == 0)
+		arch_seccomp_spec_mitigate(task);
+	set_task_syscall_work(task, SECCOMP);
+}
+
+#ifdef CONFIG_SECCOMP_FILTER
+/* Returns 1 if the parent is an ancestor of the child. */
+static int is_ancestor(struct seccomp_filter *parent,
+		       struct seccomp_filter *child)
+{
+	/* NULL is the root ancestor. */
+	if (parent == NULL)
+		return 1;
+	for (; child; child = child->prev)
+		if (child == parent)
+			return 1;
+	return 0;
+}
+
+/**
+ * seccomp_can_sync_threads: checks if all threads can be synchronized
+ *
+ * Expects sighand and cred_guard_mutex locks to be held.
+ *
+ * Returns 0 on success, -ve on error, or the pid of a thread which was
+ * either not in the correct seccomp mode or did not have an ancestral
+ * seccomp filter.
+ */
+static inline pid_t seccomp_can_sync_threads(void)
+{
+	struct task_struct *thread, *caller;
+
+	BUG_ON(!mutex_is_locked(&current->signal->cred_guard_mutex));
+	assert_spin_locked(&current->sighand->siglock);
+
+	/* Validate all threads being eligible for synchronization. */
+	caller = current;
+	for_each_thread(caller, thread) {
+		pid_t failed;
+
+		/* Skip current, since it is initiating the sync. */
+		if (thread == caller)
+			continue;
+
+		if (thread->seccomp.mode == SECCOMP_MODE_DISABLED ||
+		    (thread->seccomp.mode == SECCOMP_MODE_FILTER &&
+		     is_ancestor(thread->seccomp.filter,
+				 caller->seccomp.filter)))
+			continue;
+
+		/* Return the first thread that cannot be synchronized. */
+		failed = task_pid_vnr(thread);
+		/* If the pid cannot be resolved, then return -ESRCH */
+		if (WARN_ON(failed == 0))
+			failed = -ESRCH;
+		return failed;
+	}
+
+	return 0;
+}
+
+static inline void seccomp_filter_free(struct seccomp_filter *filter)
+{
+	if (filter) {
+		bpf_prog_destroy(filter->prog);
+		kfree(filter);
+	}
+}
+
+static void __seccomp_filter_orphan(struct seccomp_filter *orig)
+{
+	while (orig && refcount_dec_and_test(&orig->users)) {
+		if (waitqueue_active(&orig->wqh))
+			wake_up_poll(&orig->wqh, EPOLLHUP);
+		orig = orig->prev;
+	}
+}
+
+static void __put_seccomp_filter(struct seccomp_filter *orig)
+{
+	/* Clean up single-reference branches iteratively. */
+	while (orig && refcount_dec_and_test(&orig->refs)) {
+		struct seccomp_filter *freeme = orig;
+		orig = orig->prev;
+		seccomp_filter_free(freeme);
+	}
+}
+
+static void __seccomp_filter_release(struct seccomp_filter *orig)
+{
+	/* Notify about any unused filters in the task's former filter tree. */
+	__seccomp_filter_orphan(orig);
+	/* Finally drop all references to the task's former tree. */
+	__put_seccomp_filter(orig);
+}
+
+/**
+ * seccomp_filter_release - Detach the task from its filter tree,
+ *			    drop its reference count, and notify
+ *			    about unused filters
+ *
+ * This function should only be called when the task is exiting as
+ * it detaches it from its filter tree. As such, READ_ONCE() and
+ * barriers are not needed here, as would normally be needed.
+ */
+void seccomp_filter_release(struct task_struct *tsk)
+{
+	struct seccomp_filter *orig = tsk->seccomp.filter;
+
+	/* We are effectively holding the siglock by not having any sighand. */
+	WARN_ON(tsk->sighand != NULL);
+
+	/* Detach task from its filter tree. */
+	tsk->seccomp.filter = NULL;
+	__seccomp_filter_release(orig);
+}
+
+/**
+ * seccomp_sync_threads: sets all threads to use current's filter
+ *
+ * Expects sighand and cred_guard_mutex locks to be held, and for
+ * seccomp_can_sync_threads() to have returned success already
+ * without dropping the locks.
+ *
+ */
+static inline void seccomp_sync_threads(unsigned long flags)
+{
+	struct task_struct *thread, *caller;
+
+	BUG_ON(!mutex_is_locked(&current->signal->cred_guard_mutex));
+	assert_spin_locked(&current->sighand->siglock);
+
+	/* Synchronize all threads. */
+	caller = current;
+	for_each_thread(caller, thread) {
+		/* Skip current, since it needs no changes. */
+		if (thread == caller)
+			continue;
+
+		/* Get a task reference for the new leaf node. */
+		get_seccomp_filter(caller);
+
+		/*
+		 * Drop the task reference to the shared ancestor since
+		 * current's path will hold a reference.  (This also
+		 * allows a put before the assignment.)
+		 */
+		__seccomp_filter_release(thread->seccomp.filter);
+
+		/* Make our new filter tree visible. */
+		smp_store_release(&thread->seccomp.filter,
+				  caller->seccomp.filter);
+		atomic_set(&thread->seccomp.filter_count,
+			   atomic_read(&caller->seccomp.filter_count));
+
+		/*
+		 * Don't let an unprivileged task work around
+		 * the no_new_privs restriction by creating
+		 * a thread that sets it up, enters seccomp,
+		 * then dies.
+		 */
+		if (task_no_new_privs(caller))
+			task_set_no_new_privs(thread);
+
+		/*
+		 * Opt the other thread into seccomp if needed.
+		 * As threads are considered to be trust-realm
+		 * equivalent (see ptrace_may_access), it is safe to
+		 * allow one thread to transition the other.
+		 */
+		if (thread->seccomp.mode == SECCOMP_MODE_DISABLED)
+			seccomp_assign_mode(thread, SECCOMP_MODE_FILTER,
+					    flags);
+	}
+}
+
+/**
+ * seccomp_prepare_filter: Prepares a seccomp filter for use.
+ * @fprog: BPF program to install
+ *
+ * Returns filter on success or an ERR_PTR on failure.
+ */
+static struct seccomp_filter *seccomp_prepare_filter(struct sock_fprog *fprog)
+{
+	struct seccomp_filter *sfilter;
+	int ret;
+	const bool save_orig =
+#if defined(CONFIG_CHECKPOINT_RESTORE) || defined(SECCOMP_ARCH_NATIVE)
+		true;
+#else
+		false;
+#endif
+
+	if (fprog->len == 0 || fprog->len > BPF_MAXINSNS)
+		return ERR_PTR(-EINVAL);
+
+	BUG_ON(INT_MAX / fprog->len < sizeof(struct sock_filter));
+
+	/*
+	 * Installing a seccomp filter requires that the task has
+	 * CAP_SYS_ADMIN in its namespace or be running with no_new_privs.
+	 * This avoids scenarios where unprivileged tasks can affect the
+	 * behavior of privileged children.
+	 */
+	if (!task_no_new_privs(current) &&
+			!ns_capable_noaudit(current_user_ns(), CAP_SYS_ADMIN))
+		return ERR_PTR(-EACCES);
+
+	/* Allocate a new seccomp_filter */
+	sfilter = kzalloc(sizeof(*sfilter), GFP_KERNEL | __GFP_NOWARN);
+	if (!sfilter)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&sfilter->notify_lock);
+	ret = bpf_prog_create_from_user(&sfilter->prog, fprog,
+					seccomp_check_filter, save_orig);
+	if (ret < 0) {
+		kfree(sfilter);
+		return ERR_PTR(ret);
+	}
+
+	refcount_set(&sfilter->refs, 1);
+	refcount_set(&sfilter->users, 1);
+	init_waitqueue_head(&sfilter->wqh);
+
+	return sfilter;
+}
+
+/**
+ * seccomp_prepare_user_filter - prepares a user-supplied sock_fprog
+ * @user_filter: pointer to the user data containing a sock_fprog.
+ *
+ * Returns 0 on success and non-zero otherwise.
+ */
+static struct seccomp_filter *
+seccomp_prepare_user_filter(const char __user *user_filter)
+{
+	struct sock_fprog fprog;
+	struct seccomp_filter *filter = ERR_PTR(-EFAULT);
+
+#ifdef CONFIG_COMPAT
+	if (in_compat_syscall()) {
+		struct compat_sock_fprog fprog32;
+		if (copy_from_user(&fprog32, user_filter, sizeof(fprog32)))
+			goto out;
+		fprog.len = fprog32.len;
+		fprog.filter = compat_ptr(fprog32.filter);
+	} else /* falls through to the if below. */
+#endif
+	if (copy_from_user(&fprog, user_filter, sizeof(fprog)))
+		goto out;
+	filter = seccomp_prepare_filter(&fprog);
+out:
+	return filter;
+}
+
+#ifdef SECCOMP_ARCH_NATIVE
+/**
+ * seccomp_is_const_allow - check if filter is constant allow with given data
+ * @fprog: The BPF programs
+ * @sd: The seccomp data to check against, only syscall number and arch
+ *      number are considered constant.
+ */
+static bool seccomp_is_const_allow(struct sock_fprog_kern *fprog,
+				   struct seccomp_data *sd)
+{
+	unsigned int reg_value = 0;
+	unsigned int pc;
+	bool op_res;
+
+	if (WARN_ON_ONCE(!fprog))
+		return false;
+
+	for (pc = 0; pc < fprog->len; pc++) {
+		struct sock_filter *insn = &fprog->filter[pc];
+		u16 code = insn->code;
+		u32 k = insn->k;
+
+		switch (code) {
+		case BPF_LD | BPF_W | BPF_ABS:
+			switch (k) {
+			case offsetof(struct seccomp_data, nr):
+				reg_value = sd->nr;
+				break;
+			case offsetof(struct seccomp_data, arch):
+				reg_value = sd->arch;
+				break;
+			default:
+				/* can't optimize (non-constant value load) */
+				return false;
+			}
+			break;
+		case BPF_RET | BPF_K:
+			/* reached return with constant values only, check allow */
+			return k == SECCOMP_RET_ALLOW;
+		case BPF_JMP | BPF_JA:
+			pc += insn->k;
+			break;
+		case BPF_JMP | BPF_JEQ | BPF_K:
+		case BPF_JMP | BPF_JGE | BPF_K:
+		case BPF_JMP | BPF_JGT | BPF_K:
+		case BPF_JMP | BPF_JSET | BPF_K:
+			switch (BPF_OP(code)) {
+			case BPF_JEQ:
+				op_res = reg_value == k;
+				break;
+			case BPF_JGE:
+				op_res = reg_value >= k;
+				break;
+			case BPF_JGT:
+				op_res = reg_value > k;
+				break;
+			case BPF_JSET:
+				op_res = !!(reg_value & k);
+				break;
+			default:
+				/* can't optimize (unknown jump) */
+				return false;
+			}
+
+			pc += op_res ? insn->jt : insn->jf;
+			break;
+		case BPF_ALU | BPF_AND | BPF_K:
+			reg_value &= k;
+			break;
+		default:
+			/* can't optimize (unknown insn) */
+			return false;
+		}
+	}
+
+	/* ran off the end of the filter?! */
+	WARN_ON(1);
+	return false;
+}
+
+static void seccomp_cache_prepare_bitmap(struct seccomp_filter *sfilter,
+					 void *bitmap, const void *bitmap_prev,
+					 size_t bitmap_size, int arch)
+{
+	struct sock_fprog_kern *fprog = sfilter->prog->orig_prog;
+	struct seccomp_data sd;
+	int nr;
+
+	if (bitmap_prev) {
+		/* The new filter must be as restrictive as the last. */
+		bitmap_copy(bitmap, bitmap_prev, bitmap_size);
+	} else {
+		/* Before any filters, all syscalls are always allowed. */
+		bitmap_fill(bitmap, bitmap_size);
+	}
+
+	for (nr = 0; nr < bitmap_size; nr++) {
+		/* No bitmap change: not a cacheable action. */
+		if (!test_bit(nr, bitmap))
+			continue;
+
+		sd.nr = nr;
+		sd.arch = arch;
+
+		/* No bitmap change: continue to always allow. */
+		if (seccomp_is_const_allow(fprog, &sd))
+			continue;
+
+		/*
+		 * Not a cacheable action: always run filters.
+		 * atomic clear_bit() not needed, filter not visible yet.
+		 */
+		__clear_bit(nr, bitmap);
+	}
+}
+
+/**
+ * seccomp_cache_prepare - emulate the filter to find cacheable syscalls
+ * @sfilter: The seccomp filter
+ *
+ * Returns 0 if successful or -errno if error occurred.
+ */
+static void seccomp_cache_prepare(struct seccomp_filter *sfilter)
+{
+	struct action_cache *cache = &sfilter->cache;
+	const struct action_cache *cache_prev =
+		sfilter->prev ? &sfilter->prev->cache : NULL;
+
+	seccomp_cache_prepare_bitmap(sfilter, cache->allow_native,
+				     cache_prev ? cache_prev->allow_native : NULL,
+				     SECCOMP_ARCH_NATIVE_NR,
+				     SECCOMP_ARCH_NATIVE);
+
+#ifdef SECCOMP_ARCH_COMPAT
+	seccomp_cache_prepare_bitmap(sfilter, cache->allow_compat,
+				     cache_prev ? cache_prev->allow_compat : NULL,
+				     SECCOMP_ARCH_COMPAT_NR,
+				     SECCOMP_ARCH_COMPAT);
+#endif /* SECCOMP_ARCH_COMPAT */
+}
+#endif /* SECCOMP_ARCH_NATIVE */
+
+/**
+ * seccomp_attach_filter: validate and attach filter
+ * @flags:  flags to change filter behavior
+ * @filter: seccomp filter to add to the current process
+ *
+ * Caller must be holding current->sighand->siglock lock.
+ *
+ * Returns 0 on success, -ve on error, or
+ *   - in TSYNC mode: the pid of a thread which was either not in the correct
+ *     seccomp mode or did not have an ancestral seccomp filter
+ *   - in NEW_LISTENER mode: the fd of the new listener
+ */
+static long seccomp_attach_filter(unsigned int flags,
+				  struct seccomp_filter *filter)
+{
+	unsigned long total_insns;
+	struct seccomp_filter *walker;
+
+	assert_spin_locked(&current->sighand->siglock);
+
+	/* Validate resulting filter length. */
+	total_insns = filter->prog->len;
+	for (walker = current->seccomp.filter; walker; walker = walker->prev)
+		total_insns += walker->prog->len + 4;  /* 4 instr penalty */
+	if (total_insns > MAX_INSNS_PER_PATH)
+		return -ENOMEM;
+
+	/* If thread sync has been requested, check that it is possible. */
+	if (flags & SECCOMP_FILTER_FLAG_TSYNC) {
+		int ret;
+
+		ret = seccomp_can_sync_threads();
+		if (ret) {
+			if (flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH)
+				return -ESRCH;
+			else
+				return ret;
+		}
+	}
+
+	/* Set log flag, if present. */
+	if (flags & SECCOMP_FILTER_FLAG_LOG)
+		filter->log = true;
+
+	/* Set wait killable flag, if present. */
+	if (flags & SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV)
+		filter->wait_killable_recv = true;
+
+	/*
+	 * If there is an existing filter, make it the prev and don't drop its
+	 * task reference.
+	 */
+	filter->prev = current->seccomp.filter;
+	seccomp_cache_prepare(filter);
+	current->seccomp.filter = filter;
+	atomic_inc(&current->seccomp.filter_count);
+
+	/* Now that the new filter is in place, synchronize to all threads. */
+	if (flags & SECCOMP_FILTER_FLAG_TSYNC)
+		seccomp_sync_threads(flags);
+
+	return 0;
+}
+
+static void __get_seccomp_filter(struct seccomp_filter *filter)
+{
+	refcount_inc(&filter->refs);
+}
+
+/* get_seccomp_filter - increments the reference count of the filter on @tsk */
+void get_seccomp_filter(struct task_struct *tsk)
+{
+	struct seccomp_filter *orig = tsk->seccomp.filter;
+	if (!orig)
+		return;
+	__get_seccomp_filter(orig);
+	refcount_inc(&orig->users);
+}
+
+#endif	/* CONFIG_SECCOMP_FILTER */
+
+/* For use with seccomp_actions_logged */
+#define SECCOMP_LOG_KILL_PROCESS	(1 << 0)
+#define SECCOMP_LOG_KILL_THREAD		(1 << 1)
+#define SECCOMP_LOG_TRAP		(1 << 2)
+#define SECCOMP_LOG_ERRNO		(1 << 3)
+#define SECCOMP_LOG_TRACE		(1 << 4)
+#define SECCOMP_LOG_LOG			(1 << 5)
+#define SECCOMP_LOG_ALLOW		(1 << 6)
+#define SECCOMP_LOG_USER_NOTIF		(1 << 7)
+
+static u32 seccomp_actions_logged = SECCOMP_LOG_KILL_PROCESS |
+				    SECCOMP_LOG_KILL_THREAD  |
+				    SECCOMP_LOG_TRAP  |
+				    SECCOMP_LOG_ERRNO |
+				    SECCOMP_LOG_USER_NOTIF |
+				    SECCOMP_LOG_TRACE |
+				    SECCOMP_LOG_LOG;
+
+static inline void seccomp_log(unsigned long syscall, long signr, u32 action,
+			       bool requested)
+{
+	bool log = false;
+
+	switch (action) {
+	case SECCOMP_RET_ALLOW:
+		break;
+	case SECCOMP_RET_TRAP:
+		log = requested && seccomp_actions_logged & SECCOMP_LOG_TRAP;
+		break;
+	case SECCOMP_RET_ERRNO:
+		log = requested && seccomp_actions_logged & SECCOMP_LOG_ERRNO;
+		break;
+	case SECCOMP_RET_TRACE:
+		log = requested && seccomp_actions_logged & SECCOMP_LOG_TRACE;
+		break;
+	case SECCOMP_RET_USER_NOTIF:
+		log = requested && seccomp_actions_logged & SECCOMP_LOG_USER_NOTIF;
+		break;
+	case SECCOMP_RET_LOG:
+		log = seccomp_actions_logged & SECCOMP_LOG_LOG;
+		break;
+	case SECCOMP_RET_KILL_THREAD:
+		log = seccomp_actions_logged & SECCOMP_LOG_KILL_THREAD;
+		break;
+	case SECCOMP_RET_KILL_PROCESS:
+	default:
+		log = seccomp_actions_logged & SECCOMP_LOG_KILL_PROCESS;
+	}
+
+	/*
+	 * Emit an audit message when the action is RET_KILL_*, RET_LOG, or the
+	 * FILTER_FLAG_LOG bit was set. The admin has the ability to silence
+	 * any action from being logged by removing the action name from the
+	 * seccomp_actions_logged sysctl.
+	 */
+	if (!log)
+		return;
+
+	audit_seccomp(syscall, signr, action);
+}
+
+/*
+ * Secure computing mode 1 allows only read/write/exit/sigreturn.
+ * To be fully secure this must be combined with rlimit
+ * to limit the stack allocations too.
+ */
+static const int mode1_syscalls[] = {
+	__NR_seccomp_read, __NR_seccomp_write, __NR_seccomp_exit, __NR_seccomp_sigreturn,
+	-1, /* negative terminated */
+};
+
+static void __secure_computing_strict(int this_syscall)
+{
+	const int *allowed_syscalls = mode1_syscalls;
+#ifdef CONFIG_COMPAT
+	if (in_compat_syscall())
+		allowed_syscalls = get_compat_mode1_syscalls();
+#endif
+	do {
+		if (*allowed_syscalls == this_syscall)
+			return;
+	} while (*++allowed_syscalls != -1);
+
+#ifdef SECCOMP_DEBUG
+	dump_stack();
+#endif
+	current->seccomp.mode = SECCOMP_MODE_DEAD;
+	seccomp_log(this_syscall, SIGKILL, SECCOMP_RET_KILL_THREAD, true);
+	do_exit(SIGKILL);
+}
+
+#ifndef CONFIG_HAVE_ARCH_SECCOMP_FILTER
+void secure_computing_strict(int this_syscall)
+{
+	int mode = current->seccomp.mode;
+
+	if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) &&
+	    unlikely(current->ptrace & PT_SUSPEND_SECCOMP))
+		return;
+
+	if (mode == SECCOMP_MODE_DISABLED)
+		return;
+	else if (mode == SECCOMP_MODE_STRICT)
+		__secure_computing_strict(this_syscall);
+	else
+		BUG();
+}
+#else
+
+#ifdef CONFIG_SECCOMP_FILTER
+static u64 seccomp_next_notify_id(struct seccomp_filter *filter)
+{
+	/*
+	 * Note: overflow is ok here, the id just needs to be unique per
+	 * filter.
+	 */
+	lockdep_assert_held(&filter->notify_lock);
+	return filter->notif->next_id++;
+}
+
+static void seccomp_handle_addfd(struct seccomp_kaddfd *addfd, struct seccomp_knotif *n)
+{
+	int fd;
+
+	/*
+	 * Remove the notification, and reset the list pointers, indicating
+	 * that it has been handled.
+	 */
+	list_del_init(&addfd->list);
+	if (!addfd->setfd)
+		fd = receive_fd(addfd->file, addfd->flags);
+	else
+		fd = receive_fd_replace(addfd->fd, addfd->file, addfd->flags);
+	addfd->ret = fd;
+
+	if (addfd->ioctl_flags & SECCOMP_ADDFD_FLAG_SEND) {
+		/* If we fail reset and return an error to the notifier */
+		if (fd < 0) {
+			n->state = SECCOMP_NOTIFY_SENT;
+		} else {
+			/* Return the FD we just added */
+			n->flags = 0;
+			n->error = 0;
+			n->val = fd;
+		}
+	}
+
+	/*
+	 * Mark the notification as completed. From this point, addfd mem
+	 * might be invalidated and we can't safely read it anymore.
+	 */
+	complete(&addfd->completion);
+}
+
+static bool should_sleep_killable(struct seccomp_filter *match,
+				  struct seccomp_knotif *n)
+{
+	return match->wait_killable_recv && n->state == SECCOMP_NOTIFY_SENT;
+}
+
+static int seccomp_do_user_notification(int this_syscall,
+					struct seccomp_filter *match,
+					const struct seccomp_data *sd)
+{
+	int err;
+	u32 flags = 0;
+	long ret = 0;
+	struct seccomp_knotif n = {};
+	struct seccomp_kaddfd *addfd, *tmp;
+
+	mutex_lock(&match->notify_lock);
+	err = -ENOSYS;
+	if (!match->notif)
+		goto out;
+
+	n.task = current;
+	n.state = SECCOMP_NOTIFY_INIT;
+	n.data = sd;
+	n.id = seccomp_next_notify_id(match);
+	init_completion(&n.ready);
+	list_add_tail(&n.list, &match->notif->notifications);
+	INIT_LIST_HEAD(&n.addfd);
+
+	up(&match->notif->request);
+	wake_up_poll(&match->wqh, EPOLLIN | EPOLLRDNORM);
+
+	/*
+	 * This is where we wait for a reply from userspace.
+	 */
+	do {
+		bool wait_killable = should_sleep_killable(match, &n);
+
+		mutex_unlock(&match->notify_lock);
+		if (wait_killable)
+			err = wait_for_completion_killable(&n.ready);
+		else
+			err = wait_for_completion_interruptible(&n.ready);
+		mutex_lock(&match->notify_lock);
+
+		if (err != 0) {
+			/*
+			 * Check to see if the notifcation got picked up and
+			 * whether we should switch to wait killable.
+			 */
+			if (!wait_killable && should_sleep_killable(match, &n))
+				continue;
+
+			goto interrupted;
+		}
+
+		addfd = list_first_entry_or_null(&n.addfd,
+						 struct seccomp_kaddfd, list);
+		/* Check if we were woken up by a addfd message */
+		if (addfd)
+			seccomp_handle_addfd(addfd, &n);
+
+	}  while (n.state != SECCOMP_NOTIFY_REPLIED);
+
+	ret = n.val;
+	err = n.error;
+	flags = n.flags;
+
+interrupted:
+	/* If there were any pending addfd calls, clear them out */
+	list_for_each_entry_safe(addfd, tmp, &n.addfd, list) {
+		/* The process went away before we got a chance to handle it */
+		addfd->ret = -ESRCH;
+		list_del_init(&addfd->list);
+		complete(&addfd->completion);
+	}
+
+	/*
+	 * Note that it's possible the listener died in between the time when
+	 * we were notified of a response (or a signal) and when we were able to
+	 * re-acquire the lock, so only delete from the list if the
+	 * notification actually exists.
+	 *
+	 * Also note that this test is only valid because there's no way to
+	 * *reattach* to a notifier right now. If one is added, we'll need to
+	 * keep track of the notif itself and make sure they match here.
+	 */
+	if (match->notif)
+		list_del(&n.list);
+out:
+	mutex_unlock(&match->notify_lock);
+
+	/* Userspace requests to continue the syscall. */
+	if (flags & SECCOMP_USER_NOTIF_FLAG_CONTINUE)
+		return 0;
+
+	syscall_set_return_value(current, current_pt_regs(),
+				 err, ret);
+	return -1;
+}
+
+static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
+			    const bool recheck_after_trace)
+{
+	u32 filter_ret, action;
+	struct seccomp_filter *match = NULL;
+	int data;
+	struct seccomp_data sd_local;
+
+	/*
+	 * Make sure that any changes to mode from another thread have
+	 * been seen after SYSCALL_WORK_SECCOMP was seen.
+	 */
+	smp_rmb();
+
+	if (!sd) {
+		populate_seccomp_data(&sd_local);
+		sd = &sd_local;
+	}
+
+	filter_ret = seccomp_run_filters(sd, &match);
+	data = filter_ret & SECCOMP_RET_DATA;
+	action = filter_ret & SECCOMP_RET_ACTION_FULL;
+
+	switch (action) {
+	case SECCOMP_RET_ERRNO:
+		/* Set low-order bits as an errno, capped at MAX_ERRNO. */
+		if (data > MAX_ERRNO)
+			data = MAX_ERRNO;
+		syscall_set_return_value(current, current_pt_regs(),
+					 -data, 0);
+		goto skip;
+
+	case SECCOMP_RET_TRAP:
+		/* Show the handler the original registers. */
+		syscall_rollback(current, current_pt_regs());
+		/* Let the filter pass back 16 bits of data. */
+		force_sig_seccomp(this_syscall, data, false);
+		goto skip;
+
+	case SECCOMP_RET_TRACE:
+		/* We've been put in this state by the ptracer already. */
+		if (recheck_after_trace)
+			return 0;
+
+		/* ENOSYS these calls if there is no tracer attached. */
+		if (!ptrace_event_enabled(current, PTRACE_EVENT_SECCOMP)) {
+			syscall_set_return_value(current,
+						 current_pt_regs(),
+						 -ENOSYS, 0);
+			goto skip;
+		}
+
+		/* Allow the BPF to provide the event message */
+		ptrace_event(PTRACE_EVENT_SECCOMP, data);
+		/*
+		 * The delivery of a fatal signal during event
+		 * notification may silently skip tracer notification,
+		 * which could leave us with a potentially unmodified
+		 * syscall that the tracer would have liked to have
+		 * changed. Since the process is about to die, we just
+		 * force the syscall to be skipped and let the signal
+		 * kill the process and correctly handle any tracer exit
+		 * notifications.
+		 */
+		if (fatal_signal_pending(current))
+			goto skip;
+		/* Check if the tracer forced the syscall to be skipped. */
+		this_syscall = syscall_get_nr(current, current_pt_regs());
+		if (this_syscall < 0)
+			goto skip;
+
+		/*
+		 * Recheck the syscall, since it may have changed. This
+		 * intentionally uses a NULL struct seccomp_data to force
+		 * a reload of all registers. This does not goto skip since
+		 * a skip would have already been reported.
+		 */
+		if (__seccomp_filter(this_syscall, NULL, true))
+			return -1;
+
+		return 0;
+
+	case SECCOMP_RET_USER_NOTIF:
+		if (seccomp_do_user_notification(this_syscall, match, sd))
+			goto skip;
+
+		return 0;
+
+	case SECCOMP_RET_LOG:
+		seccomp_log(this_syscall, 0, action, true);
+		return 0;
+
+	case SECCOMP_RET_ALLOW:
+		/*
+		 * Note that the "match" filter will always be NULL for
+		 * this action since SECCOMP_RET_ALLOW is the starting
+		 * state in seccomp_run_filters().
+		 */
+		return 0;
+
+	case SECCOMP_RET_KILL_THREAD:
+	case SECCOMP_RET_KILL_PROCESS:
+	default:
+		current->seccomp.mode = SECCOMP_MODE_DEAD;
+		seccomp_log(this_syscall, SIGSYS, action, true);
+		/* Dump core only if this is the last remaining thread. */
+		if (action != SECCOMP_RET_KILL_THREAD ||
+		    (atomic_read(&current->signal->live) == 1)) {
+			/* Show the original registers in the dump. */
+			syscall_rollback(current, current_pt_regs());
+			/* Trigger a coredump with SIGSYS */
+			force_sig_seccomp(this_syscall, data, true);
+		} else {
+			do_exit(SIGSYS);
+		}
+		return -1; /* skip the syscall go directly to signal handling */
+	}
+
+	unreachable();
+
+skip:
+	seccomp_log(this_syscall, 0, action, match ? match->log : false);
+	return -1;
+}
+#else
+static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
+			    const bool recheck_after_trace)
+{
+	BUG();
+
+	return -1;
+}
+#endif
+
+int __secure_computing(const struct seccomp_data *sd)
+{
+	int mode = current->seccomp.mode;
+	int this_syscall;
+
+	if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) &&
+	    unlikely(current->ptrace & PT_SUSPEND_SECCOMP))
+		return 0;
+
+	this_syscall = sd ? sd->nr :
+		syscall_get_nr(current, current_pt_regs());
+
+	switch (mode) {
+	case SECCOMP_MODE_STRICT:
+		__secure_computing_strict(this_syscall);  /* may call do_exit */
+		return 0;
+	case SECCOMP_MODE_FILTER:
+		return __seccomp_filter(this_syscall, sd, false);
+	/* Surviving SECCOMP_RET_KILL_* must be proactively impossible. */
+	case SECCOMP_MODE_DEAD:
+		WARN_ON_ONCE(1);
+		do_exit(SIGKILL);
+		return -1;
+	default:
+		BUG();
+	}
+}
+#endif /* CONFIG_HAVE_ARCH_SECCOMP_FILTER */
+
+long prctl_get_seccomp(void)
+{
+	return current->seccomp.mode;
+}
+
+/**
+ * seccomp_set_mode_strict: internal function for setting strict seccomp
+ *
+ * Once current->seccomp.mode is non-zero, it may not be changed.
+ *
+ * Returns 0 on success or -EINVAL on failure.
+ */
+static long seccomp_set_mode_strict(void)
+{
+	const unsigned long seccomp_mode = SECCOMP_MODE_STRICT;
+	long ret = -EINVAL;
+
+	spin_lock_irq(&current->sighand->siglock);
+
+	if (!seccomp_may_assign_mode(seccomp_mode))
+		goto out;
+
+#ifdef TIF_NOTSC
+	disable_TSC();
+#endif
+	seccomp_assign_mode(current, seccomp_mode, 0);
+	ret = 0;
+
+out:
+	spin_unlock_irq(&current->sighand->siglock);
+
+	return ret;
+}
+
+#ifdef CONFIG_SECCOMP_FILTER
+static void seccomp_notify_free(struct seccomp_filter *filter)
+{
+	kfree(filter->notif);
+	filter->notif = NULL;
+}
+
+static void seccomp_notify_detach(struct seccomp_filter *filter)
+{
+	struct seccomp_knotif *knotif;
+
+	if (!filter)
+		return;
+
+	mutex_lock(&filter->notify_lock);
+
+	/*
+	 * If this file is being closed because e.g. the task who owned it
+	 * died, let's wake everyone up who was waiting on us.
+	 */
+	list_for_each_entry(knotif, &filter->notif->notifications, list) {
+		if (knotif->state == SECCOMP_NOTIFY_REPLIED)
+			continue;
+
+		knotif->state = SECCOMP_NOTIFY_REPLIED;
+		knotif->error = -ENOSYS;
+		knotif->val = 0;
+
+		/*
+		 * We do not need to wake up any pending addfd messages, as
+		 * the notifier will do that for us, as this just looks
+		 * like a standard reply.
+		 */
+		complete(&knotif->ready);
+	}
+
+	seccomp_notify_free(filter);
+	mutex_unlock(&filter->notify_lock);
+}
+
+static int seccomp_notify_release(struct inode *inode, struct file *file)
+{
+	struct seccomp_filter *filter = file->private_data;
+
+	seccomp_notify_detach(filter);
+	__put_seccomp_filter(filter);
+	return 0;
+}
+
+/* must be called with notif_lock held */
+static inline struct seccomp_knotif *
+find_notification(struct seccomp_filter *filter, u64 id)
+{
+	struct seccomp_knotif *cur;
+
+	lockdep_assert_held(&filter->notify_lock);
+
+	list_for_each_entry(cur, &filter->notif->notifications, list) {
+		if (cur->id == id)
+			return cur;
+	}
+
+	return NULL;
+}
+
+
+static long seccomp_notify_recv(struct seccomp_filter *filter,
+				void __user *buf)
+{
+	struct seccomp_knotif *knotif = NULL, *cur;
+	struct seccomp_notif unotif;
+	ssize_t ret;
+
+	/* Verify that we're not given garbage to keep struct extensible. */
+	ret = check_zeroed_user(buf, sizeof(unotif));
+	if (ret < 0)
+		return ret;
+	if (!ret)
+		return -EINVAL;
+
+	memset(&unotif, 0, sizeof(unotif));
+
+	ret = down_interruptible(&filter->notif->request);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&filter->notify_lock);
+	list_for_each_entry(cur, &filter->notif->notifications, list) {
+		if (cur->state == SECCOMP_NOTIFY_INIT) {
+			knotif = cur;
+			break;
+		}
+	}
+
+	/*
+	 * If we didn't find a notification, it could be that the task was
+	 * interrupted by a fatal signal between the time we were woken and
+	 * when we were able to acquire the rw lock.
+	 */
+	if (!knotif) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	unotif.id = knotif->id;
+	unotif.pid = task_pid_vnr(knotif->task);
+	unotif.data = *(knotif->data);
+
+	knotif->state = SECCOMP_NOTIFY_SENT;
+	wake_up_poll(&filter->wqh, EPOLLOUT | EPOLLWRNORM);
+	ret = 0;
+out:
+	mutex_unlock(&filter->notify_lock);
+
+	if (ret == 0 && copy_to_user(buf, &unotif, sizeof(unotif))) {
+		ret = -EFAULT;
+
+		/*
+		 * Userspace screwed up. To make sure that we keep this
+		 * notification alive, let's reset it back to INIT. It
+		 * may have died when we released the lock, so we need to make
+		 * sure it's still around.
+		 */
+		mutex_lock(&filter->notify_lock);
+		knotif = find_notification(filter, unotif.id);
+		if (knotif) {
+			/* Reset the process to make sure it's not stuck */
+			if (should_sleep_killable(filter, knotif))
+				complete(&knotif->ready);
+			knotif->state = SECCOMP_NOTIFY_INIT;
+			up(&filter->notif->request);
+		}
+		mutex_unlock(&filter->notify_lock);
+	}
+
+	return ret;
+}
+
+static long seccomp_notify_send(struct seccomp_filter *filter,
+				void __user *buf)
+{
+	struct seccomp_notif_resp resp = {};
+	struct seccomp_knotif *knotif;
+	long ret;
+
+	if (copy_from_user(&resp, buf, sizeof(resp)))
+		return -EFAULT;
+
+	if (resp.flags & ~SECCOMP_USER_NOTIF_FLAG_CONTINUE)
+		return -EINVAL;
+
+	if ((resp.flags & SECCOMP_USER_NOTIF_FLAG_CONTINUE) &&
+	    (resp.error || resp.val))
+		return -EINVAL;
+
+	ret = mutex_lock_interruptible(&filter->notify_lock);
+	if (ret < 0)
+		return ret;
+
+	knotif = find_notification(filter, resp.id);
+	if (!knotif) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	/* Allow exactly one reply. */
+	if (knotif->state != SECCOMP_NOTIFY_SENT) {
+		ret = -EINPROGRESS;
+		goto out;
+	}
+
+	ret = 0;
+	knotif->state = SECCOMP_NOTIFY_REPLIED;
+	knotif->error = resp.error;
+	knotif->val = resp.val;
+	knotif->flags = resp.flags;
+	complete(&knotif->ready);
+out:
+	mutex_unlock(&filter->notify_lock);
+	return ret;
+}
+
+static long seccomp_notify_id_valid(struct seccomp_filter *filter,
+				    void __user *buf)
+{
+	struct seccomp_knotif *knotif;
+	u64 id;
+	long ret;
+
+	if (copy_from_user(&id, buf, sizeof(id)))
+		return -EFAULT;
+
+	ret = mutex_lock_interruptible(&filter->notify_lock);
+	if (ret < 0)
+		return ret;
+
+	knotif = find_notification(filter, id);
+	if (knotif && knotif->state == SECCOMP_NOTIFY_SENT)
+		ret = 0;
+	else
+		ret = -ENOENT;
+
+	mutex_unlock(&filter->notify_lock);
+	return ret;
+}
+
+static long seccomp_notify_addfd(struct seccomp_filter *filter,
+				 struct seccomp_notif_addfd __user *uaddfd,
+				 unsigned int size)
+{
+	struct seccomp_notif_addfd addfd;
+	struct seccomp_knotif *knotif;
+	struct seccomp_kaddfd kaddfd;
+	int ret;
+
+	BUILD_BUG_ON(sizeof(addfd) < SECCOMP_NOTIFY_ADDFD_SIZE_VER0);
+	BUILD_BUG_ON(sizeof(addfd) != SECCOMP_NOTIFY_ADDFD_SIZE_LATEST);
+
+	if (size < SECCOMP_NOTIFY_ADDFD_SIZE_VER0 || size >= PAGE_SIZE)
+		return -EINVAL;
+
+	ret = copy_struct_from_user(&addfd, sizeof(addfd), uaddfd, size);
+	if (ret)
+		return ret;
+
+	if (addfd.newfd_flags & ~O_CLOEXEC)
+		return -EINVAL;
+
+	if (addfd.flags & ~(SECCOMP_ADDFD_FLAG_SETFD | SECCOMP_ADDFD_FLAG_SEND))
+		return -EINVAL;
+
+	if (addfd.newfd && !(addfd.flags & SECCOMP_ADDFD_FLAG_SETFD))
+		return -EINVAL;
+
+	kaddfd.file = fget(addfd.srcfd);
+	if (!kaddfd.file)
+		return -EBADF;
+
+	kaddfd.ioctl_flags = addfd.flags;
+	kaddfd.flags = addfd.newfd_flags;
+	kaddfd.setfd = addfd.flags & SECCOMP_ADDFD_FLAG_SETFD;
+	kaddfd.fd = addfd.newfd;
+	init_completion(&kaddfd.completion);
+
+	ret = mutex_lock_interruptible(&filter->notify_lock);
+	if (ret < 0)
+		goto out;
+
+	knotif = find_notification(filter, addfd.id);
+	if (!knotif) {
+		ret = -ENOENT;
+		goto out_unlock;
+	}
+
+	/*
+	 * We do not want to allow for FD injection to occur before the
+	 * notification has been picked up by a userspace handler, or after
+	 * the notification has been replied to.
+	 */
+	if (knotif->state != SECCOMP_NOTIFY_SENT) {
+		ret = -EINPROGRESS;
+		goto out_unlock;
+	}
+
+	if (addfd.flags & SECCOMP_ADDFD_FLAG_SEND) {
+		/*
+		 * Disallow queuing an atomic addfd + send reply while there are
+		 * some addfd requests still to process.
+		 *
+		 * There is no clear reason to support it and allows us to keep
+		 * the loop on the other side straight-forward.
+		 */
+		if (!list_empty(&knotif->addfd)) {
+			ret = -EBUSY;
+			goto out_unlock;
+		}
+
+		/* Allow exactly only one reply */
+		knotif->state = SECCOMP_NOTIFY_REPLIED;
+	}
+
+	list_add(&kaddfd.list, &knotif->addfd);
+	complete(&knotif->ready);
+	mutex_unlock(&filter->notify_lock);
+
+	/* Now we wait for it to be processed or be interrupted */
+	ret = wait_for_completion_interruptible(&kaddfd.completion);
+	if (ret == 0) {
+		/*
+		 * We had a successful completion. The other side has already
+		 * removed us from the addfd queue, and
+		 * wait_for_completion_interruptible has a memory barrier upon
+		 * success that lets us read this value directly without
+		 * locking.
+		 */
+		ret = kaddfd.ret;
+		goto out;
+	}
+
+	mutex_lock(&filter->notify_lock);
+	/*
+	 * Even though we were woken up by a signal and not a successful
+	 * completion, a completion may have happened in the mean time.
+	 *
+	 * We need to check again if the addfd request has been handled,
+	 * and if not, we will remove it from the queue.
+	 */
+	if (list_empty(&kaddfd.list))
+		ret = kaddfd.ret;
+	else
+		list_del(&kaddfd.list);
+
+out_unlock:
+	mutex_unlock(&filter->notify_lock);
+out:
+	fput(kaddfd.file);
+
+	return ret;
+}
+
+static long seccomp_notify_ioctl(struct file *file, unsigned int cmd,
+				 unsigned long arg)
+{
+	struct seccomp_filter *filter = file->private_data;
+	void __user *buf = (void __user *)arg;
+
+	/* Fixed-size ioctls */
+	switch (cmd) {
+	case SECCOMP_IOCTL_NOTIF_RECV:
+		return seccomp_notify_recv(filter, buf);
+	case SECCOMP_IOCTL_NOTIF_SEND:
+		return seccomp_notify_send(filter, buf);
+	case SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR:
+	case SECCOMP_IOCTL_NOTIF_ID_VALID:
+		return seccomp_notify_id_valid(filter, buf);
+	}
+
+	/* Extensible Argument ioctls */
+#define EA_IOCTL(cmd)	((cmd) & ~(IOC_INOUT | IOCSIZE_MASK))
+	switch (EA_IOCTL(cmd)) {
+	case EA_IOCTL(SECCOMP_IOCTL_NOTIF_ADDFD):
+		return seccomp_notify_addfd(filter, buf, _IOC_SIZE(cmd));
+	default:
+		return -EINVAL;
+	}
+}
+
+static __poll_t seccomp_notify_poll(struct file *file,
+				    struct poll_table_struct *poll_tab)
+{
+	struct seccomp_filter *filter = file->private_data;
+	__poll_t ret = 0;
+	struct seccomp_knotif *cur;
+
+	poll_wait(file, &filter->wqh, poll_tab);
+
+	if (mutex_lock_interruptible(&filter->notify_lock) < 0)
+		return EPOLLERR;
+
+	list_for_each_entry(cur, &filter->notif->notifications, list) {
+		if (cur->state == SECCOMP_NOTIFY_INIT)
+			ret |= EPOLLIN | EPOLLRDNORM;
+		if (cur->state == SECCOMP_NOTIFY_SENT)
+			ret |= EPOLLOUT | EPOLLWRNORM;
+		if ((ret & EPOLLIN) && (ret & EPOLLOUT))
+			break;
+	}
+
+	mutex_unlock(&filter->notify_lock);
+
+	if (refcount_read(&filter->users) == 0)
+		ret |= EPOLLHUP;
+
+	return ret;
+}
+
+static const struct file_operations seccomp_notify_ops = {
+	.poll = seccomp_notify_poll,
+	.release = seccomp_notify_release,
+	.unlocked_ioctl = seccomp_notify_ioctl,
+	.compat_ioctl = seccomp_notify_ioctl,
+};
+
+static struct file *init_listener(struct seccomp_filter *filter)
+{
+	struct file *ret;
+
+	ret = ERR_PTR(-ENOMEM);
+	filter->notif = kzalloc(sizeof(*(filter->notif)), GFP_KERNEL);
+	if (!filter->notif)
+		goto out;
+
+	sema_init(&filter->notif->request, 0);
+	filter->notif->next_id = get_random_u64();
+	INIT_LIST_HEAD(&filter->notif->notifications);
+
+	ret = anon_inode_getfile("seccomp notify", &seccomp_notify_ops,
+				 filter, O_RDWR);
+	if (IS_ERR(ret))
+		goto out_notif;
+
+	/* The file has a reference to it now */
+	__get_seccomp_filter(filter);
+
+out_notif:
+	if (IS_ERR(ret))
+		seccomp_notify_free(filter);
+out:
+	return ret;
+}
+
+/*
+ * Does @new_child have a listener while an ancestor also has a listener?
+ * If so, we'll want to reject this filter.
+ * This only has to be tested for the current process, even in the TSYNC case,
+ * because TSYNC installs @child with the same parent on all threads.
+ * Note that @new_child is not hooked up to its parent at this point yet, so
+ * we use current->seccomp.filter.
+ */
+static bool has_duplicate_listener(struct seccomp_filter *new_child)
+{
+	struct seccomp_filter *cur;
+
+	/* must be protected against concurrent TSYNC */
+	lockdep_assert_held(&current->sighand->siglock);
+
+	if (!new_child->notif)
+		return false;
+	for (cur = current->seccomp.filter; cur; cur = cur->prev) {
+		if (cur->notif)
+			return true;
+	}
+
+	return false;
+}
+
+/**
+ * seccomp_set_mode_filter: internal function for setting seccomp filter
+ * @flags:  flags to change filter behavior
+ * @filter: struct sock_fprog containing filter
+ *
+ * This function may be called repeatedly to install additional filters.
+ * Every filter successfully installed will be evaluated (in reverse order)
+ * for each system call the task makes.
+ *
+ * Once current->seccomp.mode is non-zero, it may not be changed.
+ *
+ * Returns 0 on success or -EINVAL on failure.
+ */
+static long seccomp_set_mode_filter(unsigned int flags,
+				    const char __user *filter)
+{
+	const unsigned long seccomp_mode = SECCOMP_MODE_FILTER;
+	struct seccomp_filter *prepared = NULL;
+	long ret = -EINVAL;
+	int listener = -1;
+	struct file *listener_f = NULL;
+
+	/* Validate flags. */
+	if (flags & ~SECCOMP_FILTER_FLAG_MASK)
+		return -EINVAL;
+
+	/*
+	 * In the successful case, NEW_LISTENER returns the new listener fd.
+	 * But in the failure case, TSYNC returns the thread that died. If you
+	 * combine these two flags, there's no way to tell whether something
+	 * succeeded or failed. So, let's disallow this combination if the user
+	 * has not explicitly requested no errors from TSYNC.
+	 */
+	if ((flags & SECCOMP_FILTER_FLAG_TSYNC) &&
+	    (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) &&
+	    ((flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH) == 0))
+		return -EINVAL;
+
+	/*
+	 * The SECCOMP_FILTER_FLAG_WAIT_KILLABLE_SENT flag doesn't make sense
+	 * without the SECCOMP_FILTER_FLAG_NEW_LISTENER flag.
+	 */
+	if ((flags & SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV) &&
+	    ((flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) == 0))
+		return -EINVAL;
+
+	/* Prepare the new filter before holding any locks. */
+	prepared = seccomp_prepare_user_filter(filter);
+	if (IS_ERR(prepared))
+		return PTR_ERR(prepared);
+
+	if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) {
+		listener = get_unused_fd_flags(O_CLOEXEC);
+		if (listener < 0) {
+			ret = listener;
+			goto out_free;
+		}
+
+		listener_f = init_listener(prepared);
+		if (IS_ERR(listener_f)) {
+			put_unused_fd(listener);
+			ret = PTR_ERR(listener_f);
+			goto out_free;
+		}
+	}
+
+	/*
+	 * Make sure we cannot change seccomp or nnp state via TSYNC
+	 * while another thread is in the middle of calling exec.
+	 */
+	if (flags & SECCOMP_FILTER_FLAG_TSYNC &&
+	    mutex_lock_killable(&current->signal->cred_guard_mutex))
+		goto out_put_fd;
+
+	spin_lock_irq(&current->sighand->siglock);
+
+	if (!seccomp_may_assign_mode(seccomp_mode))
+		goto out;
+
+	if (has_duplicate_listener(prepared)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	ret = seccomp_attach_filter(flags, prepared);
+	if (ret)
+		goto out;
+	/* Do not free the successfully attached filter. */
+	prepared = NULL;
+
+	seccomp_assign_mode(current, seccomp_mode, flags);
+out:
+	spin_unlock_irq(&current->sighand->siglock);
+	if (flags & SECCOMP_FILTER_FLAG_TSYNC)
+		mutex_unlock(&current->signal->cred_guard_mutex);
+out_put_fd:
+	if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) {
+		if (ret) {
+			listener_f->private_data = NULL;
+			fput(listener_f);
+			put_unused_fd(listener);
+			seccomp_notify_detach(prepared);
+		} else {
+			fd_install(listener, listener_f);
+			ret = listener;
+		}
+	}
+out_free:
+	seccomp_filter_free(prepared);
+	return ret;
+}
+#else
+static inline long seccomp_set_mode_filter(unsigned int flags,
+					   const char __user *filter)
+{
+	return -EINVAL;
+}
+#endif
+
+static long seccomp_get_action_avail(const char __user *uaction)
+{
+	u32 action;
+
+	if (copy_from_user(&action, uaction, sizeof(action)))
+		return -EFAULT;
+
+	switch (action) {
+	case SECCOMP_RET_KILL_PROCESS:
+	case SECCOMP_RET_KILL_THREAD:
+	case SECCOMP_RET_TRAP:
+	case SECCOMP_RET_ERRNO:
+	case SECCOMP_RET_USER_NOTIF:
+	case SECCOMP_RET_TRACE:
+	case SECCOMP_RET_LOG:
+	case SECCOMP_RET_ALLOW:
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static long seccomp_get_notif_sizes(void __user *usizes)
+{
+	struct seccomp_notif_sizes sizes = {
+		.seccomp_notif = sizeof(struct seccomp_notif),
+		.seccomp_notif_resp = sizeof(struct seccomp_notif_resp),
+		.seccomp_data = sizeof(struct seccomp_data),
+	};
+
+	if (copy_to_user(usizes, &sizes, sizeof(sizes)))
+		return -EFAULT;
+
+	return 0;
+}
+
+/* Common entry point for both prctl and syscall. */
+static long do_seccomp(unsigned int op, unsigned int flags,
+		       void __user *uargs)
+{
+	switch (op) {
+	case SECCOMP_SET_MODE_STRICT:
+		if (flags != 0 || uargs != NULL)
+			return -EINVAL;
+		return seccomp_set_mode_strict();
+	case SECCOMP_SET_MODE_FILTER:
+		return seccomp_set_mode_filter(flags, uargs);
+	case SECCOMP_GET_ACTION_AVAIL:
+		if (flags != 0)
+			return -EINVAL;
+
+		return seccomp_get_action_avail(uargs);
+	case SECCOMP_GET_NOTIF_SIZES:
+		if (flags != 0)
+			return -EINVAL;
+
+		return seccomp_get_notif_sizes(uargs);
+	default:
+		return -EINVAL;
+	}
+}
+
+SYSCALL_DEFINE3(seccomp, unsigned int, op, unsigned int, flags,
+			 void __user *, uargs)
+{
+	return do_seccomp(op, flags, uargs);
+}
+
+/**
+ * prctl_set_seccomp: configures current->seccomp.mode
+ * @seccomp_mode: requested mode to use
+ * @filter: optional struct sock_fprog for use with SECCOMP_MODE_FILTER
+ *
+ * Returns 0 on success or -EINVAL on failure.
+ */
+long prctl_set_seccomp(unsigned long seccomp_mode, void __user *filter)
+{
+	unsigned int op;
+	void __user *uargs;
+
+	switch (seccomp_mode) {
+	case SECCOMP_MODE_STRICT:
+		op = SECCOMP_SET_MODE_STRICT;
+		/*
+		 * Setting strict mode through prctl always ignored filter,
+		 * so make sure it is always NULL here to pass the internal
+		 * check in do_seccomp().
+		 */
+		uargs = NULL;
+		break;
+	case SECCOMP_MODE_FILTER:
+		op = SECCOMP_SET_MODE_FILTER;
+		uargs = filter;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* prctl interface doesn't have flags, so they are always zero. */
+	return do_seccomp(op, 0, uargs);
+}
+
+#if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE)
+static struct seccomp_filter *get_nth_filter(struct task_struct *task,
+					     unsigned long filter_off)
+{
+	struct seccomp_filter *orig, *filter;
+	unsigned long count;
+
+	/*
+	 * Note: this is only correct because the caller should be the (ptrace)
+	 * tracer of the task, otherwise lock_task_sighand is needed.
+	 */
+	spin_lock_irq(&task->sighand->siglock);
+
+	if (task->seccomp.mode != SECCOMP_MODE_FILTER) {
+		spin_unlock_irq(&task->sighand->siglock);
+		return ERR_PTR(-EINVAL);
+	}
+
+	orig = task->seccomp.filter;
+	__get_seccomp_filter(orig);
+	spin_unlock_irq(&task->sighand->siglock);
+
+	count = 0;
+	for (filter = orig; filter; filter = filter->prev)
+		count++;
+
+	if (filter_off >= count) {
+		filter = ERR_PTR(-ENOENT);
+		goto out;
+	}
+
+	count -= filter_off;
+	for (filter = orig; filter && count > 1; filter = filter->prev)
+		count--;
+
+	if (WARN_ON(count != 1 || !filter)) {
+		filter = ERR_PTR(-ENOENT);
+		goto out;
+	}
+
+	__get_seccomp_filter(filter);
+
+out:
+	__put_seccomp_filter(orig);
+	return filter;
+}
+
+long seccomp_get_filter(struct task_struct *task, unsigned long filter_off,
+			void __user *data)
+{
+	struct seccomp_filter *filter;
+	struct sock_fprog_kern *fprog;
+	long ret;
+
+	if (!capable(CAP_SYS_ADMIN) ||
+	    current->seccomp.mode != SECCOMP_MODE_DISABLED) {
+		return -EACCES;
+	}
+
+	filter = get_nth_filter(task, filter_off);
+	if (IS_ERR(filter))
+		return PTR_ERR(filter);
+
+	fprog = filter->prog->orig_prog;
+	if (!fprog) {
+		/* This must be a new non-cBPF filter, since we save
+		 * every cBPF filter's orig_prog above when
+		 * CONFIG_CHECKPOINT_RESTORE is enabled.
+		 */
+		ret = -EMEDIUMTYPE;
+		goto out;
+	}
+
+	ret = fprog->len;
+	if (!data)
+		goto out;
+
+	if (copy_to_user(data, fprog->filter, bpf_classic_proglen(fprog)))
+		ret = -EFAULT;
+
+out:
+	__put_seccomp_filter(filter);
+	return ret;
+}
+
+long seccomp_get_metadata(struct task_struct *task,
+			  unsigned long size, void __user *data)
+{
+	long ret;
+	struct seccomp_filter *filter;
+	struct seccomp_metadata kmd = {};
+
+	if (!capable(CAP_SYS_ADMIN) ||
+	    current->seccomp.mode != SECCOMP_MODE_DISABLED) {
+		return -EACCES;
+	}
+
+	size = min_t(unsigned long, size, sizeof(kmd));
+
+	if (size < sizeof(kmd.filter_off))
+		return -EINVAL;
+
+	if (copy_from_user(&kmd.filter_off, data, sizeof(kmd.filter_off)))
+		return -EFAULT;
+
+	filter = get_nth_filter(task, kmd.filter_off);
+	if (IS_ERR(filter))
+		return PTR_ERR(filter);
+
+	if (filter->log)
+		kmd.flags |= SECCOMP_FILTER_FLAG_LOG;
+
+	ret = size;
+	if (copy_to_user(data, &kmd, size))
+		ret = -EFAULT;
+
+	__put_seccomp_filter(filter);
+	return ret;
+}
+#endif
+
+#ifdef CONFIG_SYSCTL
+
+/* Human readable action names for friendly sysctl interaction */
+#define SECCOMP_RET_KILL_PROCESS_NAME	"kill_process"
+#define SECCOMP_RET_KILL_THREAD_NAME	"kill_thread"
+#define SECCOMP_RET_TRAP_NAME		"trap"
+#define SECCOMP_RET_ERRNO_NAME		"errno"
+#define SECCOMP_RET_USER_NOTIF_NAME	"user_notif"
+#define SECCOMP_RET_TRACE_NAME		"trace"
+#define SECCOMP_RET_LOG_NAME		"log"
+#define SECCOMP_RET_ALLOW_NAME		"allow"
+
+static const char seccomp_actions_avail[] =
+				SECCOMP_RET_KILL_PROCESS_NAME	" "
+				SECCOMP_RET_KILL_THREAD_NAME	" "
+				SECCOMP_RET_TRAP_NAME		" "
+				SECCOMP_RET_ERRNO_NAME		" "
+				SECCOMP_RET_USER_NOTIF_NAME     " "
+				SECCOMP_RET_TRACE_NAME		" "
+				SECCOMP_RET_LOG_NAME		" "
+				SECCOMP_RET_ALLOW_NAME;
+
+struct seccomp_log_name {
+	u32		log;
+	const char	*name;
+};
+
+static const struct seccomp_log_name seccomp_log_names[] = {
+	{ SECCOMP_LOG_KILL_PROCESS, SECCOMP_RET_KILL_PROCESS_NAME },
+	{ SECCOMP_LOG_KILL_THREAD, SECCOMP_RET_KILL_THREAD_NAME },
+	{ SECCOMP_LOG_TRAP, SECCOMP_RET_TRAP_NAME },
+	{ SECCOMP_LOG_ERRNO, SECCOMP_RET_ERRNO_NAME },
+	{ SECCOMP_LOG_USER_NOTIF, SECCOMP_RET_USER_NOTIF_NAME },
+	{ SECCOMP_LOG_TRACE, SECCOMP_RET_TRACE_NAME },
+	{ SECCOMP_LOG_LOG, SECCOMP_RET_LOG_NAME },
+	{ SECCOMP_LOG_ALLOW, SECCOMP_RET_ALLOW_NAME },
+	{ }
+};
+
+static bool seccomp_names_from_actions_logged(char *names, size_t size,
+					      u32 actions_logged,
+					      const char *sep)
+{
+	const struct seccomp_log_name *cur;
+	bool append_sep = false;
+
+	for (cur = seccomp_log_names; cur->name && size; cur++) {
+		ssize_t ret;
+
+		if (!(actions_logged & cur->log))
+			continue;
+
+		if (append_sep) {
+			ret = strscpy(names, sep, size);
+			if (ret < 0)
+				return false;
+
+			names += ret;
+			size -= ret;
+		} else
+			append_sep = true;
+
+		ret = strscpy(names, cur->name, size);
+		if (ret < 0)
+			return false;
+
+		names += ret;
+		size -= ret;
+	}
+
+	return true;
+}
+
+static bool seccomp_action_logged_from_name(u32 *action_logged,
+					    const char *name)
+{
+	const struct seccomp_log_name *cur;
+
+	for (cur = seccomp_log_names; cur->name; cur++) {
+		if (!strcmp(cur->name, name)) {
+			*action_logged = cur->log;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+static bool seccomp_actions_logged_from_names(u32 *actions_logged, char *names)
+{
+	char *name;
+
+	*actions_logged = 0;
+	while ((name = strsep(&names, " ")) && *name) {
+		u32 action_logged = 0;
+
+		if (!seccomp_action_logged_from_name(&action_logged, name))
+			return false;
+
+		*actions_logged |= action_logged;
+	}
+
+	return true;
+}
+
+static int read_actions_logged(struct ctl_table *ro_table, void *buffer,
+			       size_t *lenp, loff_t *ppos)
+{
+	char names[sizeof(seccomp_actions_avail)];
+	struct ctl_table table;
+
+	memset(names, 0, sizeof(names));
+
+	if (!seccomp_names_from_actions_logged(names, sizeof(names),
+					       seccomp_actions_logged, " "))
+		return -EINVAL;
+
+	table = *ro_table;
+	table.data = names;
+	table.maxlen = sizeof(names);
+	return proc_dostring(&table, 0, buffer, lenp, ppos);
+}
+
+static int write_actions_logged(struct ctl_table *ro_table, void *buffer,
+				size_t *lenp, loff_t *ppos, u32 *actions_logged)
+{
+	char names[sizeof(seccomp_actions_avail)];
+	struct ctl_table table;
+	int ret;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	memset(names, 0, sizeof(names));
+
+	table = *ro_table;
+	table.data = names;
+	table.maxlen = sizeof(names);
+	ret = proc_dostring(&table, 1, buffer, lenp, ppos);
+	if (ret)
+		return ret;
+
+	if (!seccomp_actions_logged_from_names(actions_logged, table.data))
+		return -EINVAL;
+
+	if (*actions_logged & SECCOMP_LOG_ALLOW)
+		return -EINVAL;
+
+	seccomp_actions_logged = *actions_logged;
+	return 0;
+}
+
+static void audit_actions_logged(u32 actions_logged, u32 old_actions_logged,
+				 int ret)
+{
+	char names[sizeof(seccomp_actions_avail)];
+	char old_names[sizeof(seccomp_actions_avail)];
+	const char *new = names;
+	const char *old = old_names;
+
+	if (!audit_enabled)
+		return;
+
+	memset(names, 0, sizeof(names));
+	memset(old_names, 0, sizeof(old_names));
+
+	if (ret)
+		new = "?";
+	else if (!actions_logged)
+		new = "(none)";
+	else if (!seccomp_names_from_actions_logged(names, sizeof(names),
+						    actions_logged, ","))
+		new = "?";
+
+	if (!old_actions_logged)
+		old = "(none)";
+	else if (!seccomp_names_from_actions_logged(old_names,
+						    sizeof(old_names),
+						    old_actions_logged, ","))
+		old = "?";
+
+	return audit_seccomp_actions_logged(new, old, !ret);
+}
+
+static int seccomp_actions_logged_handler(struct ctl_table *ro_table, int write,
+					  void *buffer, size_t *lenp,
+					  loff_t *ppos)
+{
+	int ret;
+
+	if (write) {
+		u32 actions_logged = 0;
+		u32 old_actions_logged = seccomp_actions_logged;
+
+		ret = write_actions_logged(ro_table, buffer, lenp, ppos,
+					   &actions_logged);
+		audit_actions_logged(actions_logged, old_actions_logged, ret);
+	} else
+		ret = read_actions_logged(ro_table, buffer, lenp, ppos);
+
+	return ret;
+}
+
+static struct ctl_path seccomp_sysctl_path[] = {
+	{ .procname = "kernel", },
+	{ .procname = "seccomp", },
+	{ }
+};
+
+static struct ctl_table seccomp_sysctl_table[] = {
+	{
+		.procname	= "actions_avail",
+		.data		= (void *) &seccomp_actions_avail,
+		.maxlen		= sizeof(seccomp_actions_avail),
+		.mode		= 0444,
+		.proc_handler	= proc_dostring,
+	},
+	{
+		.procname	= "actions_logged",
+		.mode		= 0644,
+		.proc_handler	= seccomp_actions_logged_handler,
+	},
+	{ }
+};
+
+static int __init seccomp_sysctl_init(void)
+{
+	struct ctl_table_header *hdr;
+
+	hdr = register_sysctl_paths(seccomp_sysctl_path, seccomp_sysctl_table);
+	if (!hdr)
+		pr_warn("sysctl registration failed\n");
+	else
+		kmemleak_not_leak(hdr);
+
+	return 0;
+}
+
+device_initcall(seccomp_sysctl_init)
+
+#endif /* CONFIG_SYSCTL */
+
+#ifdef CONFIG_SECCOMP_CACHE_DEBUG
+/* Currently CONFIG_SECCOMP_CACHE_DEBUG implies SECCOMP_ARCH_NATIVE */
+static void proc_pid_seccomp_cache_arch(struct seq_file *m, const char *name,
+					const void *bitmap, size_t bitmap_size)
+{
+	int nr;
+
+	for (nr = 0; nr < bitmap_size; nr++) {
+		bool cached = test_bit(nr, bitmap);
+		char *status = cached ? "ALLOW" : "FILTER";
+
+		seq_printf(m, "%s %d %s\n", name, nr, status);
+	}
+}
+
+int proc_pid_seccomp_cache(struct seq_file *m, struct pid_namespace *ns,
+			   struct pid *pid, struct task_struct *task)
+{
+	struct seccomp_filter *f;
+	unsigned long flags;
+
+	/*
+	 * We don't want some sandboxed process to know what their seccomp
+	 * filters consist of.
+	 */
+	if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN))
+		return -EACCES;
+
+	if (!lock_task_sighand(task, &flags))
+		return -ESRCH;
+
+	f = READ_ONCE(task->seccomp.filter);
+	if (!f) {
+		unlock_task_sighand(task, &flags);
+		return 0;
+	}
+
+	/* prevent filter from being freed while we are printing it */
+	__get_seccomp_filter(f);
+	unlock_task_sighand(task, &flags);
+
+	proc_pid_seccomp_cache_arch(m, SECCOMP_ARCH_NATIVE_NAME,
+				    f->cache.allow_native,
+				    SECCOMP_ARCH_NATIVE_NR);
+
+#ifdef SECCOMP_ARCH_COMPAT
+	proc_pid_seccomp_cache_arch(m, SECCOMP_ARCH_COMPAT_NAME,
+				    f->cache.allow_compat,
+				    SECCOMP_ARCH_COMPAT_NR);
+#endif /* SECCOMP_ARCH_COMPAT */
+
+	__put_seccomp_filter(f);
+	return 0;
+}
+#endif /* CONFIG_SECCOMP_CACHE_DEBUG */
diff --git a/kernel/signal.c b/kernel/signal.c
new file mode 100644
index 000000000..5d45f5da2
--- /dev/null
+++ b/kernel/signal.c
@@ -0,0 +1,4805 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/kernel/signal.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  1997-11-02  Modified for POSIX.1b signals by Richard Henderson
+ *
+ *  2003-06-02  Jim Houston - Concurrent Computer Corp.
+ *		Changes to use preallocated sigqueue structures
+ *		to allow signals to be sent reliably.
+ */
+
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/user.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/task.h>
+#include <linux/sched/task_stack.h>
+#include <linux/sched/cputime.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/proc_fs.h>
+#include <linux/tty.h>
+#include <linux/binfmts.h>
+#include <linux/coredump.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/ptrace.h>
+#include <linux/signal.h>
+#include <linux/signalfd.h>
+#include <linux/ratelimit.h>
+#include <linux/task_work.h>
+#include <linux/capability.h>
+#include <linux/freezer.h>
+#include <linux/pid_namespace.h>
+#include <linux/nsproxy.h>
+#include <linux/user_namespace.h>
+#include <linux/uprobes.h>
+#include <linux/compat.h>
+#include <linux/cn_proc.h>
+#include <linux/compiler.h>
+#include <linux/posix-timers.h>
+#include <linux/cgroup.h>
+#include <linux/audit.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/signal.h>
+
+#include <asm/param.h>
+#include <linux/uaccess.h>
+#include <asm/unistd.h>
+#include <asm/siginfo.h>
+#include <asm/cacheflush.h>
+#include <asm/syscall.h>	/* for syscall_get_* */
+
+/*
+ * SLAB caches for signal bits.
+ */
+
+static struct kmem_cache *sigqueue_cachep;
+
+int print_fatal_signals __read_mostly;
+
+static void __user *sig_handler(struct task_struct *t, int sig)
+{
+	return t->sighand->action[sig - 1].sa.sa_handler;
+}
+
+static inline bool sig_handler_ignored(void __user *handler, int sig)
+{
+	/* Is it explicitly or implicitly ignored? */
+	return handler == SIG_IGN ||
+	       (handler == SIG_DFL && sig_kernel_ignore(sig));
+}
+
+static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
+{
+	void __user *handler;
+
+	handler = sig_handler(t, sig);
+
+	/* SIGKILL and SIGSTOP may not be sent to the global init */
+	if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
+		return true;
+
+	if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
+	    handler == SIG_DFL && !(force && sig_kernel_only(sig)))
+		return true;
+
+	/* Only allow kernel generated signals to this kthread */
+	if (unlikely((t->flags & PF_KTHREAD) &&
+		     (handler == SIG_KTHREAD_KERNEL) && !force))
+		return true;
+
+	return sig_handler_ignored(handler, sig);
+}
+
+static bool sig_ignored(struct task_struct *t, int sig, bool force)
+{
+	/*
+	 * Blocked signals are never ignored, since the
+	 * signal handler may change by the time it is
+	 * unblocked.
+	 */
+	if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
+		return false;
+
+	/*
+	 * Tracers may want to know about even ignored signal unless it
+	 * is SIGKILL which can't be reported anyway but can be ignored
+	 * by SIGNAL_UNKILLABLE task.
+	 */
+	if (t->ptrace && sig != SIGKILL)
+		return false;
+
+	return sig_task_ignored(t, sig, force);
+}
+
+/*
+ * Re-calculate pending state from the set of locally pending
+ * signals, globally pending signals, and blocked signals.
+ */
+static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
+{
+	unsigned long ready;
+	long i;
+
+	switch (_NSIG_WORDS) {
+	default:
+		for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
+			ready |= signal->sig[i] &~ blocked->sig[i];
+		break;
+
+	case 4: ready  = signal->sig[3] &~ blocked->sig[3];
+		ready |= signal->sig[2] &~ blocked->sig[2];
+		ready |= signal->sig[1] &~ blocked->sig[1];
+		ready |= signal->sig[0] &~ blocked->sig[0];
+		break;
+
+	case 2: ready  = signal->sig[1] &~ blocked->sig[1];
+		ready |= signal->sig[0] &~ blocked->sig[0];
+		break;
+
+	case 1: ready  = signal->sig[0] &~ blocked->sig[0];
+	}
+	return ready !=	0;
+}
+
+#define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
+
+static bool recalc_sigpending_tsk(struct task_struct *t)
+{
+	if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
+	    PENDING(&t->pending, &t->blocked) ||
+	    PENDING(&t->signal->shared_pending, &t->blocked) ||
+	    cgroup_task_frozen(t)) {
+		set_tsk_thread_flag(t, TIF_SIGPENDING);
+		return true;
+	}
+
+	/*
+	 * We must never clear the flag in another thread, or in current
+	 * when it's possible the current syscall is returning -ERESTART*.
+	 * So we don't clear it here, and only callers who know they should do.
+	 */
+	return false;
+}
+
+/*
+ * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
+ * This is superfluous when called on current, the wakeup is a harmless no-op.
+ */
+void recalc_sigpending_and_wake(struct task_struct *t)
+{
+	if (recalc_sigpending_tsk(t))
+		signal_wake_up(t, 0);
+}
+
+void recalc_sigpending(void)
+{
+	if (!recalc_sigpending_tsk(current) && !freezing(current))
+		clear_thread_flag(TIF_SIGPENDING);
+
+}
+EXPORT_SYMBOL(recalc_sigpending);
+
+void calculate_sigpending(void)
+{
+	/* Have any signals or users of TIF_SIGPENDING been delayed
+	 * until after fork?
+	 */
+	spin_lock_irq(&current->sighand->siglock);
+	set_tsk_thread_flag(current, TIF_SIGPENDING);
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+}
+
+/* Given the mask, find the first available signal that should be serviced. */
+
+#define SYNCHRONOUS_MASK \
+	(sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
+	 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
+
+int next_signal(struct sigpending *pending, sigset_t *mask)
+{
+	unsigned long i, *s, *m, x;
+	int sig = 0;
+
+	s = pending->signal.sig;
+	m = mask->sig;
+
+	/*
+	 * Handle the first word specially: it contains the
+	 * synchronous signals that need to be dequeued first.
+	 */
+	x = *s &~ *m;
+	if (x) {
+		if (x & SYNCHRONOUS_MASK)
+			x &= SYNCHRONOUS_MASK;
+		sig = ffz(~x) + 1;
+		return sig;
+	}
+
+	switch (_NSIG_WORDS) {
+	default:
+		for (i = 1; i < _NSIG_WORDS; ++i) {
+			x = *++s &~ *++m;
+			if (!x)
+				continue;
+			sig = ffz(~x) + i*_NSIG_BPW + 1;
+			break;
+		}
+		break;
+
+	case 2:
+		x = s[1] &~ m[1];
+		if (!x)
+			break;
+		sig = ffz(~x) + _NSIG_BPW + 1;
+		break;
+
+	case 1:
+		/* Nothing to do */
+		break;
+	}
+
+	return sig;
+}
+
+static inline void print_dropped_signal(int sig)
+{
+	static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
+
+	if (!print_fatal_signals)
+		return;
+
+	if (!__ratelimit(&ratelimit_state))
+		return;
+
+	pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
+				current->comm, current->pid, sig);
+}
+
+/**
+ * task_set_jobctl_pending - set jobctl pending bits
+ * @task: target task
+ * @mask: pending bits to set
+ *
+ * Clear @mask from @task->jobctl.  @mask must be subset of
+ * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
+ * %JOBCTL_TRAPPING.  If stop signo is being set, the existing signo is
+ * cleared.  If @task is already being killed or exiting, this function
+ * becomes noop.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ *
+ * RETURNS:
+ * %true if @mask is set, %false if made noop because @task was dying.
+ */
+bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
+{
+	BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
+			JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
+	BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
+
+	if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
+		return false;
+
+	if (mask & JOBCTL_STOP_SIGMASK)
+		task->jobctl &= ~JOBCTL_STOP_SIGMASK;
+
+	task->jobctl |= mask;
+	return true;
+}
+
+/**
+ * task_clear_jobctl_trapping - clear jobctl trapping bit
+ * @task: target task
+ *
+ * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
+ * Clear it and wake up the ptracer.  Note that we don't need any further
+ * locking.  @task->siglock guarantees that @task->parent points to the
+ * ptracer.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+void task_clear_jobctl_trapping(struct task_struct *task)
+{
+	if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
+		task->jobctl &= ~JOBCTL_TRAPPING;
+		smp_mb();	/* advised by wake_up_bit() */
+		wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
+	}
+}
+
+/**
+ * task_clear_jobctl_pending - clear jobctl pending bits
+ * @task: target task
+ * @mask: pending bits to clear
+ *
+ * Clear @mask from @task->jobctl.  @mask must be subset of
+ * %JOBCTL_PENDING_MASK.  If %JOBCTL_STOP_PENDING is being cleared, other
+ * STOP bits are cleared together.
+ *
+ * If clearing of @mask leaves no stop or trap pending, this function calls
+ * task_clear_jobctl_trapping().
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
+{
+	BUG_ON(mask & ~JOBCTL_PENDING_MASK);
+
+	if (mask & JOBCTL_STOP_PENDING)
+		mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
+
+	task->jobctl &= ~mask;
+
+	if (!(task->jobctl & JOBCTL_PENDING_MASK))
+		task_clear_jobctl_trapping(task);
+}
+
+/**
+ * task_participate_group_stop - participate in a group stop
+ * @task: task participating in a group stop
+ *
+ * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
+ * Group stop states are cleared and the group stop count is consumed if
+ * %JOBCTL_STOP_CONSUME was set.  If the consumption completes the group
+ * stop, the appropriate `SIGNAL_*` flags are set.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ *
+ * RETURNS:
+ * %true if group stop completion should be notified to the parent, %false
+ * otherwise.
+ */
+static bool task_participate_group_stop(struct task_struct *task)
+{
+	struct signal_struct *sig = task->signal;
+	bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
+
+	WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
+
+	task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
+
+	if (!consume)
+		return false;
+
+	if (!WARN_ON_ONCE(sig->group_stop_count == 0))
+		sig->group_stop_count--;
+
+	/*
+	 * Tell the caller to notify completion iff we are entering into a
+	 * fresh group stop.  Read comment in do_signal_stop() for details.
+	 */
+	if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
+		signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
+		return true;
+	}
+	return false;
+}
+
+void task_join_group_stop(struct task_struct *task)
+{
+	unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK;
+	struct signal_struct *sig = current->signal;
+
+	if (sig->group_stop_count) {
+		sig->group_stop_count++;
+		mask |= JOBCTL_STOP_CONSUME;
+	} else if (!(sig->flags & SIGNAL_STOP_STOPPED))
+		return;
+
+	/* Have the new thread join an on-going signal group stop */
+	task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
+}
+
+/*
+ * allocate a new signal queue record
+ * - this may be called without locks if and only if t == current, otherwise an
+ *   appropriate lock must be held to stop the target task from exiting
+ */
+static struct sigqueue *
+__sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags,
+		 int override_rlimit, const unsigned int sigqueue_flags)
+{
+	struct sigqueue *q = NULL;
+	struct ucounts *ucounts = NULL;
+	long sigpending;
+
+	/*
+	 * Protect access to @t credentials. This can go away when all
+	 * callers hold rcu read lock.
+	 *
+	 * NOTE! A pending signal will hold on to the user refcount,
+	 * and we get/put the refcount only when the sigpending count
+	 * changes from/to zero.
+	 */
+	rcu_read_lock();
+	ucounts = task_ucounts(t);
+	sigpending = inc_rlimit_get_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
+	rcu_read_unlock();
+	if (!sigpending)
+		return NULL;
+
+	if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
+		q = kmem_cache_alloc(sigqueue_cachep, gfp_flags);
+	} else {
+		print_dropped_signal(sig);
+	}
+
+	if (unlikely(q == NULL)) {
+		dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
+	} else {
+		INIT_LIST_HEAD(&q->list);
+		q->flags = sigqueue_flags;
+		q->ucounts = ucounts;
+	}
+	return q;
+}
+
+static void __sigqueue_free(struct sigqueue *q)
+{
+	if (q->flags & SIGQUEUE_PREALLOC)
+		return;
+	if (q->ucounts) {
+		dec_rlimit_put_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING);
+		q->ucounts = NULL;
+	}
+	kmem_cache_free(sigqueue_cachep, q);
+}
+
+void flush_sigqueue(struct sigpending *queue)
+{
+	struct sigqueue *q;
+
+	sigemptyset(&queue->signal);
+	while (!list_empty(&queue->list)) {
+		q = list_entry(queue->list.next, struct sigqueue , list);
+		list_del_init(&q->list);
+		__sigqueue_free(q);
+	}
+}
+
+/*
+ * Flush all pending signals for this kthread.
+ */
+void flush_signals(struct task_struct *t)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&t->sighand->siglock, flags);
+	clear_tsk_thread_flag(t, TIF_SIGPENDING);
+	flush_sigqueue(&t->pending);
+	flush_sigqueue(&t->signal->shared_pending);
+	spin_unlock_irqrestore(&t->sighand->siglock, flags);
+}
+EXPORT_SYMBOL(flush_signals);
+
+#ifdef CONFIG_POSIX_TIMERS
+static void __flush_itimer_signals(struct sigpending *pending)
+{
+	sigset_t signal, retain;
+	struct sigqueue *q, *n;
+
+	signal = pending->signal;
+	sigemptyset(&retain);
+
+	list_for_each_entry_safe(q, n, &pending->list, list) {
+		int sig = q->info.si_signo;
+
+		if (likely(q->info.si_code != SI_TIMER)) {
+			sigaddset(&retain, sig);
+		} else {
+			sigdelset(&signal, sig);
+			list_del_init(&q->list);
+			__sigqueue_free(q);
+		}
+	}
+
+	sigorsets(&pending->signal, &signal, &retain);
+}
+
+void flush_itimer_signals(void)
+{
+	struct task_struct *tsk = current;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tsk->sighand->siglock, flags);
+	__flush_itimer_signals(&tsk->pending);
+	__flush_itimer_signals(&tsk->signal->shared_pending);
+	spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+}
+#endif
+
+void ignore_signals(struct task_struct *t)
+{
+	int i;
+
+	for (i = 0; i < _NSIG; ++i)
+		t->sighand->action[i].sa.sa_handler = SIG_IGN;
+
+	flush_signals(t);
+}
+
+/*
+ * Flush all handlers for a task.
+ */
+
+void
+flush_signal_handlers(struct task_struct *t, int force_default)
+{
+	int i;
+	struct k_sigaction *ka = &t->sighand->action[0];
+	for (i = _NSIG ; i != 0 ; i--) {
+		if (force_default || ka->sa.sa_handler != SIG_IGN)
+			ka->sa.sa_handler = SIG_DFL;
+		ka->sa.sa_flags = 0;
+#ifdef __ARCH_HAS_SA_RESTORER
+		ka->sa.sa_restorer = NULL;
+#endif
+		sigemptyset(&ka->sa.sa_mask);
+		ka++;
+	}
+}
+
+bool unhandled_signal(struct task_struct *tsk, int sig)
+{
+	void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
+	if (is_global_init(tsk))
+		return true;
+
+	if (handler != SIG_IGN && handler != SIG_DFL)
+		return false;
+
+	/* If dying, we handle all new signals by ignoring them */
+	if (fatal_signal_pending(tsk))
+		return false;
+
+	/* if ptraced, let the tracer determine */
+	return !tsk->ptrace;
+}
+
+static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
+			   bool *resched_timer)
+{
+	struct sigqueue *q, *first = NULL;
+
+	/*
+	 * Collect the siginfo appropriate to this signal.  Check if
+	 * there is another siginfo for the same signal.
+	*/
+	list_for_each_entry(q, &list->list, list) {
+		if (q->info.si_signo == sig) {
+			if (first)
+				goto still_pending;
+			first = q;
+		}
+	}
+
+	sigdelset(&list->signal, sig);
+
+	if (first) {
+still_pending:
+		list_del_init(&first->list);
+		copy_siginfo(info, &first->info);
+
+		*resched_timer =
+			(first->flags & SIGQUEUE_PREALLOC) &&
+			(info->si_code == SI_TIMER) &&
+			(info->si_sys_private);
+
+		__sigqueue_free(first);
+	} else {
+		/*
+		 * Ok, it wasn't in the queue.  This must be
+		 * a fast-pathed signal or we must have been
+		 * out of queue space.  So zero out the info.
+		 */
+		clear_siginfo(info);
+		info->si_signo = sig;
+		info->si_errno = 0;
+		info->si_code = SI_USER;
+		info->si_pid = 0;
+		info->si_uid = 0;
+	}
+}
+
+static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
+			kernel_siginfo_t *info, bool *resched_timer)
+{
+	int sig = next_signal(pending, mask);
+
+	if (sig)
+		collect_signal(sig, pending, info, resched_timer);
+	return sig;
+}
+
+/*
+ * Dequeue a signal and return the element to the caller, which is
+ * expected to free it.
+ *
+ * All callers have to hold the siglock.
+ */
+int dequeue_signal(struct task_struct *tsk, sigset_t *mask,
+		   kernel_siginfo_t *info, enum pid_type *type)
+{
+	bool resched_timer = false;
+	int signr;
+
+	/* We only dequeue private signals from ourselves, we don't let
+	 * signalfd steal them
+	 */
+	*type = PIDTYPE_PID;
+	signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
+	if (!signr) {
+		*type = PIDTYPE_TGID;
+		signr = __dequeue_signal(&tsk->signal->shared_pending,
+					 mask, info, &resched_timer);
+#ifdef CONFIG_POSIX_TIMERS
+		/*
+		 * itimer signal ?
+		 *
+		 * itimers are process shared and we restart periodic
+		 * itimers in the signal delivery path to prevent DoS
+		 * attacks in the high resolution timer case. This is
+		 * compliant with the old way of self-restarting
+		 * itimers, as the SIGALRM is a legacy signal and only
+		 * queued once. Changing the restart behaviour to
+		 * restart the timer in the signal dequeue path is
+		 * reducing the timer noise on heavy loaded !highres
+		 * systems too.
+		 */
+		if (unlikely(signr == SIGALRM)) {
+			struct hrtimer *tmr = &tsk->signal->real_timer;
+
+			if (!hrtimer_is_queued(tmr) &&
+			    tsk->signal->it_real_incr != 0) {
+				hrtimer_forward(tmr, tmr->base->get_time(),
+						tsk->signal->it_real_incr);
+				hrtimer_restart(tmr);
+			}
+		}
+#endif
+	}
+
+	recalc_sigpending();
+	if (!signr)
+		return 0;
+
+	if (unlikely(sig_kernel_stop(signr))) {
+		/*
+		 * Set a marker that we have dequeued a stop signal.  Our
+		 * caller might release the siglock and then the pending
+		 * stop signal it is about to process is no longer in the
+		 * pending bitmasks, but must still be cleared by a SIGCONT
+		 * (and overruled by a SIGKILL).  So those cases clear this
+		 * shared flag after we've set it.  Note that this flag may
+		 * remain set after the signal we return is ignored or
+		 * handled.  That doesn't matter because its only purpose
+		 * is to alert stop-signal processing code when another
+		 * processor has come along and cleared the flag.
+		 */
+		current->jobctl |= JOBCTL_STOP_DEQUEUED;
+	}
+#ifdef CONFIG_POSIX_TIMERS
+	if (resched_timer) {
+		/*
+		 * Release the siglock to ensure proper locking order
+		 * of timer locks outside of siglocks.  Note, we leave
+		 * irqs disabled here, since the posix-timers code is
+		 * about to disable them again anyway.
+		 */
+		spin_unlock(&tsk->sighand->siglock);
+		posixtimer_rearm(info);
+		spin_lock(&tsk->sighand->siglock);
+
+		/* Don't expose the si_sys_private value to userspace */
+		info->si_sys_private = 0;
+	}
+#endif
+	return signr;
+}
+EXPORT_SYMBOL_GPL(dequeue_signal);
+
+static int dequeue_synchronous_signal(kernel_siginfo_t *info)
+{
+	struct task_struct *tsk = current;
+	struct sigpending *pending = &tsk->pending;
+	struct sigqueue *q, *sync = NULL;
+
+	/*
+	 * Might a synchronous signal be in the queue?
+	 */
+	if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
+		return 0;
+
+	/*
+	 * Return the first synchronous signal in the queue.
+	 */
+	list_for_each_entry(q, &pending->list, list) {
+		/* Synchronous signals have a positive si_code */
+		if ((q->info.si_code > SI_USER) &&
+		    (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
+			sync = q;
+			goto next;
+		}
+	}
+	return 0;
+next:
+	/*
+	 * Check if there is another siginfo for the same signal.
+	 */
+	list_for_each_entry_continue(q, &pending->list, list) {
+		if (q->info.si_signo == sync->info.si_signo)
+			goto still_pending;
+	}
+
+	sigdelset(&pending->signal, sync->info.si_signo);
+	recalc_sigpending();
+still_pending:
+	list_del_init(&sync->list);
+	copy_siginfo(info, &sync->info);
+	__sigqueue_free(sync);
+	return info->si_signo;
+}
+
+/*
+ * Tell a process that it has a new active signal..
+ *
+ * NOTE! we rely on the previous spin_lock to
+ * lock interrupts for us! We can only be called with
+ * "siglock" held, and the local interrupt must
+ * have been disabled when that got acquired!
+ *
+ * No need to set need_resched since signal event passing
+ * goes through ->blocked
+ */
+void signal_wake_up_state(struct task_struct *t, unsigned int state)
+{
+	lockdep_assert_held(&t->sighand->siglock);
+
+	set_tsk_thread_flag(t, TIF_SIGPENDING);
+
+	/*
+	 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
+	 * case. We don't check t->state here because there is a race with it
+	 * executing another processor and just now entering stopped state.
+	 * By using wake_up_state, we ensure the process will wake up and
+	 * handle its death signal.
+	 */
+	if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
+		kick_process(t);
+}
+
+/*
+ * Remove signals in mask from the pending set and queue.
+ * Returns 1 if any signals were found.
+ *
+ * All callers must be holding the siglock.
+ */
+static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
+{
+	struct sigqueue *q, *n;
+	sigset_t m;
+
+	sigandsets(&m, mask, &s->signal);
+	if (sigisemptyset(&m))
+		return;
+
+	sigandnsets(&s->signal, &s->signal, mask);
+	list_for_each_entry_safe(q, n, &s->list, list) {
+		if (sigismember(mask, q->info.si_signo)) {
+			list_del_init(&q->list);
+			__sigqueue_free(q);
+		}
+	}
+}
+
+static inline int is_si_special(const struct kernel_siginfo *info)
+{
+	return info <= SEND_SIG_PRIV;
+}
+
+static inline bool si_fromuser(const struct kernel_siginfo *info)
+{
+	return info == SEND_SIG_NOINFO ||
+		(!is_si_special(info) && SI_FROMUSER(info));
+}
+
+/*
+ * called with RCU read lock from check_kill_permission()
+ */
+static bool kill_ok_by_cred(struct task_struct *t)
+{
+	const struct cred *cred = current_cred();
+	const struct cred *tcred = __task_cred(t);
+
+	return uid_eq(cred->euid, tcred->suid) ||
+	       uid_eq(cred->euid, tcred->uid) ||
+	       uid_eq(cred->uid, tcred->suid) ||
+	       uid_eq(cred->uid, tcred->uid) ||
+	       ns_capable(tcred->user_ns, CAP_KILL);
+}
+
+/*
+ * Bad permissions for sending the signal
+ * - the caller must hold the RCU read lock
+ */
+static int check_kill_permission(int sig, struct kernel_siginfo *info,
+				 struct task_struct *t)
+{
+	struct pid *sid;
+	int error;
+
+	if (!valid_signal(sig))
+		return -EINVAL;
+
+	if (!si_fromuser(info))
+		return 0;
+
+	error = audit_signal_info(sig, t); /* Let audit system see the signal */
+	if (error)
+		return error;
+
+	if (!same_thread_group(current, t) &&
+	    !kill_ok_by_cred(t)) {
+		switch (sig) {
+		case SIGCONT:
+			sid = task_session(t);
+			/*
+			 * We don't return the error if sid == NULL. The
+			 * task was unhashed, the caller must notice this.
+			 */
+			if (!sid || sid == task_session(current))
+				break;
+			fallthrough;
+		default:
+			return -EPERM;
+		}
+	}
+
+	return security_task_kill(t, info, sig, NULL);
+}
+
+/**
+ * ptrace_trap_notify - schedule trap to notify ptracer
+ * @t: tracee wanting to notify tracer
+ *
+ * This function schedules sticky ptrace trap which is cleared on the next
+ * TRAP_STOP to notify ptracer of an event.  @t must have been seized by
+ * ptracer.
+ *
+ * If @t is running, STOP trap will be taken.  If trapped for STOP and
+ * ptracer is listening for events, tracee is woken up so that it can
+ * re-trap for the new event.  If trapped otherwise, STOP trap will be
+ * eventually taken without returning to userland after the existing traps
+ * are finished by PTRACE_CONT.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+static void ptrace_trap_notify(struct task_struct *t)
+{
+	WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
+	lockdep_assert_held(&t->sighand->siglock);
+
+	task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
+	ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
+}
+
+/*
+ * Handle magic process-wide effects of stop/continue signals. Unlike
+ * the signal actions, these happen immediately at signal-generation
+ * time regardless of blocking, ignoring, or handling.  This does the
+ * actual continuing for SIGCONT, but not the actual stopping for stop
+ * signals. The process stop is done as a signal action for SIG_DFL.
+ *
+ * Returns true if the signal should be actually delivered, otherwise
+ * it should be dropped.
+ */
+static bool prepare_signal(int sig, struct task_struct *p, bool force)
+{
+	struct signal_struct *signal = p->signal;
+	struct task_struct *t;
+	sigset_t flush;
+
+	if (signal->flags & SIGNAL_GROUP_EXIT) {
+		if (signal->core_state)
+			return sig == SIGKILL;
+		/*
+		 * The process is in the middle of dying, drop the signal.
+		 */
+		return false;
+	} else if (sig_kernel_stop(sig)) {
+		/*
+		 * This is a stop signal.  Remove SIGCONT from all queues.
+		 */
+		siginitset(&flush, sigmask(SIGCONT));
+		flush_sigqueue_mask(&flush, &signal->shared_pending);
+		for_each_thread(p, t)
+			flush_sigqueue_mask(&flush, &t->pending);
+	} else if (sig == SIGCONT) {
+		unsigned int why;
+		/*
+		 * Remove all stop signals from all queues, wake all threads.
+		 */
+		siginitset(&flush, SIG_KERNEL_STOP_MASK);
+		flush_sigqueue_mask(&flush, &signal->shared_pending);
+		for_each_thread(p, t) {
+			flush_sigqueue_mask(&flush, &t->pending);
+			task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
+			if (likely(!(t->ptrace & PT_SEIZED))) {
+				t->jobctl &= ~JOBCTL_STOPPED;
+				wake_up_state(t, __TASK_STOPPED);
+			} else
+				ptrace_trap_notify(t);
+		}
+
+		/*
+		 * Notify the parent with CLD_CONTINUED if we were stopped.
+		 *
+		 * If we were in the middle of a group stop, we pretend it
+		 * was already finished, and then continued. Since SIGCHLD
+		 * doesn't queue we report only CLD_STOPPED, as if the next
+		 * CLD_CONTINUED was dropped.
+		 */
+		why = 0;
+		if (signal->flags & SIGNAL_STOP_STOPPED)
+			why |= SIGNAL_CLD_CONTINUED;
+		else if (signal->group_stop_count)
+			why |= SIGNAL_CLD_STOPPED;
+
+		if (why) {
+			/*
+			 * The first thread which returns from do_signal_stop()
+			 * will take ->siglock, notice SIGNAL_CLD_MASK, and
+			 * notify its parent. See get_signal().
+			 */
+			signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
+			signal->group_stop_count = 0;
+			signal->group_exit_code = 0;
+		}
+	}
+
+	return !sig_ignored(p, sig, force);
+}
+
+/*
+ * Test if P wants to take SIG.  After we've checked all threads with this,
+ * it's equivalent to finding no threads not blocking SIG.  Any threads not
+ * blocking SIG were ruled out because they are not running and already
+ * have pending signals.  Such threads will dequeue from the shared queue
+ * as soon as they're available, so putting the signal on the shared queue
+ * will be equivalent to sending it to one such thread.
+ */
+static inline bool wants_signal(int sig, struct task_struct *p)
+{
+	if (sigismember(&p->blocked, sig))
+		return false;
+
+	if (p->flags & PF_EXITING)
+		return false;
+
+	if (sig == SIGKILL)
+		return true;
+
+	if (task_is_stopped_or_traced(p))
+		return false;
+
+	return task_curr(p) || !task_sigpending(p);
+}
+
+static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
+{
+	struct signal_struct *signal = p->signal;
+	struct task_struct *t;
+
+	/*
+	 * Now find a thread we can wake up to take the signal off the queue.
+	 *
+	 * If the main thread wants the signal, it gets first crack.
+	 * Probably the least surprising to the average bear.
+	 */
+	if (wants_signal(sig, p))
+		t = p;
+	else if ((type == PIDTYPE_PID) || thread_group_empty(p))
+		/*
+		 * There is just one thread and it does not need to be woken.
+		 * It will dequeue unblocked signals before it runs again.
+		 */
+		return;
+	else {
+		/*
+		 * Otherwise try to find a suitable thread.
+		 */
+		t = signal->curr_target;
+		while (!wants_signal(sig, t)) {
+			t = next_thread(t);
+			if (t == signal->curr_target)
+				/*
+				 * No thread needs to be woken.
+				 * Any eligible threads will see
+				 * the signal in the queue soon.
+				 */
+				return;
+		}
+		signal->curr_target = t;
+	}
+
+	/*
+	 * Found a killable thread.  If the signal will be fatal,
+	 * then start taking the whole group down immediately.
+	 */
+	if (sig_fatal(p, sig) &&
+	    (signal->core_state || !(signal->flags & SIGNAL_GROUP_EXIT)) &&
+	    !sigismember(&t->real_blocked, sig) &&
+	    (sig == SIGKILL || !p->ptrace)) {
+		/*
+		 * This signal will be fatal to the whole group.
+		 */
+		if (!sig_kernel_coredump(sig)) {
+			/*
+			 * Start a group exit and wake everybody up.
+			 * This way we don't have other threads
+			 * running and doing things after a slower
+			 * thread has the fatal signal pending.
+			 */
+			signal->flags = SIGNAL_GROUP_EXIT;
+			signal->group_exit_code = sig;
+			signal->group_stop_count = 0;
+			t = p;
+			do {
+				task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
+				sigaddset(&t->pending.signal, SIGKILL);
+				signal_wake_up(t, 1);
+			} while_each_thread(p, t);
+			return;
+		}
+	}
+
+	/*
+	 * The signal is already in the shared-pending queue.
+	 * Tell the chosen thread to wake up and dequeue it.
+	 */
+	signal_wake_up(t, sig == SIGKILL);
+	return;
+}
+
+static inline bool legacy_queue(struct sigpending *signals, int sig)
+{
+	return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
+}
+
+static int __send_signal_locked(int sig, struct kernel_siginfo *info,
+				struct task_struct *t, enum pid_type type, bool force)
+{
+	struct sigpending *pending;
+	struct sigqueue *q;
+	int override_rlimit;
+	int ret = 0, result;
+
+	lockdep_assert_held(&t->sighand->siglock);
+
+	result = TRACE_SIGNAL_IGNORED;
+	if (!prepare_signal(sig, t, force))
+		goto ret;
+
+	pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
+	/*
+	 * Short-circuit ignored signals and support queuing
+	 * exactly one non-rt signal, so that we can get more
+	 * detailed information about the cause of the signal.
+	 */
+	result = TRACE_SIGNAL_ALREADY_PENDING;
+	if (legacy_queue(pending, sig))
+		goto ret;
+
+	result = TRACE_SIGNAL_DELIVERED;
+	/*
+	 * Skip useless siginfo allocation for SIGKILL and kernel threads.
+	 */
+	if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
+		goto out_set;
+
+	/*
+	 * Real-time signals must be queued if sent by sigqueue, or
+	 * some other real-time mechanism.  It is implementation
+	 * defined whether kill() does so.  We attempt to do so, on
+	 * the principle of least surprise, but since kill is not
+	 * allowed to fail with EAGAIN when low on memory we just
+	 * make sure at least one signal gets delivered and don't
+	 * pass on the info struct.
+	 */
+	if (sig < SIGRTMIN)
+		override_rlimit = (is_si_special(info) || info->si_code >= 0);
+	else
+		override_rlimit = 0;
+
+	q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0);
+
+	if (q) {
+		list_add_tail(&q->list, &pending->list);
+		switch ((unsigned long) info) {
+		case (unsigned long) SEND_SIG_NOINFO:
+			clear_siginfo(&q->info);
+			q->info.si_signo = sig;
+			q->info.si_errno = 0;
+			q->info.si_code = SI_USER;
+			q->info.si_pid = task_tgid_nr_ns(current,
+							task_active_pid_ns(t));
+			rcu_read_lock();
+			q->info.si_uid =
+				from_kuid_munged(task_cred_xxx(t, user_ns),
+						 current_uid());
+			rcu_read_unlock();
+			break;
+		case (unsigned long) SEND_SIG_PRIV:
+			clear_siginfo(&q->info);
+			q->info.si_signo = sig;
+			q->info.si_errno = 0;
+			q->info.si_code = SI_KERNEL;
+			q->info.si_pid = 0;
+			q->info.si_uid = 0;
+			break;
+		default:
+			copy_siginfo(&q->info, info);
+			break;
+		}
+	} else if (!is_si_special(info) &&
+		   sig >= SIGRTMIN && info->si_code != SI_USER) {
+		/*
+		 * Queue overflow, abort.  We may abort if the
+		 * signal was rt and sent by user using something
+		 * other than kill().
+		 */
+		result = TRACE_SIGNAL_OVERFLOW_FAIL;
+		ret = -EAGAIN;
+		goto ret;
+	} else {
+		/*
+		 * This is a silent loss of information.  We still
+		 * send the signal, but the *info bits are lost.
+		 */
+		result = TRACE_SIGNAL_LOSE_INFO;
+	}
+
+out_set:
+	signalfd_notify(t, sig);
+	sigaddset(&pending->signal, sig);
+
+	/* Let multiprocess signals appear after on-going forks */
+	if (type > PIDTYPE_TGID) {
+		struct multiprocess_signals *delayed;
+		hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
+			sigset_t *signal = &delayed->signal;
+			/* Can't queue both a stop and a continue signal */
+			if (sig == SIGCONT)
+				sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
+			else if (sig_kernel_stop(sig))
+				sigdelset(signal, SIGCONT);
+			sigaddset(signal, sig);
+		}
+	}
+
+	complete_signal(sig, t, type);
+ret:
+	trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
+	return ret;
+}
+
+static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
+{
+	bool ret = false;
+	switch (siginfo_layout(info->si_signo, info->si_code)) {
+	case SIL_KILL:
+	case SIL_CHLD:
+	case SIL_RT:
+		ret = true;
+		break;
+	case SIL_TIMER:
+	case SIL_POLL:
+	case SIL_FAULT:
+	case SIL_FAULT_TRAPNO:
+	case SIL_FAULT_MCEERR:
+	case SIL_FAULT_BNDERR:
+	case SIL_FAULT_PKUERR:
+	case SIL_FAULT_PERF_EVENT:
+	case SIL_SYS:
+		ret = false;
+		break;
+	}
+	return ret;
+}
+
+int send_signal_locked(int sig, struct kernel_siginfo *info,
+		       struct task_struct *t, enum pid_type type)
+{
+	/* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
+	bool force = false;
+
+	if (info == SEND_SIG_NOINFO) {
+		/* Force if sent from an ancestor pid namespace */
+		force = !task_pid_nr_ns(current, task_active_pid_ns(t));
+	} else if (info == SEND_SIG_PRIV) {
+		/* Don't ignore kernel generated signals */
+		force = true;
+	} else if (has_si_pid_and_uid(info)) {
+		/* SIGKILL and SIGSTOP is special or has ids */
+		struct user_namespace *t_user_ns;
+
+		rcu_read_lock();
+		t_user_ns = task_cred_xxx(t, user_ns);
+		if (current_user_ns() != t_user_ns) {
+			kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
+			info->si_uid = from_kuid_munged(t_user_ns, uid);
+		}
+		rcu_read_unlock();
+
+		/* A kernel generated signal? */
+		force = (info->si_code == SI_KERNEL);
+
+		/* From an ancestor pid namespace? */
+		if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
+			info->si_pid = 0;
+			force = true;
+		}
+	}
+	return __send_signal_locked(sig, info, t, type, force);
+}
+
+static void print_fatal_signal(int signr)
+{
+	struct pt_regs *regs = signal_pt_regs();
+	pr_info("potentially unexpected fatal signal %d.\n", signr);
+
+#if defined(__i386__) && !defined(__arch_um__)
+	pr_info("code at %08lx: ", regs->ip);
+	{
+		int i;
+		for (i = 0; i < 16; i++) {
+			unsigned char insn;
+
+			if (get_user(insn, (unsigned char *)(regs->ip + i)))
+				break;
+			pr_cont("%02x ", insn);
+		}
+	}
+	pr_cont("\n");
+#endif
+	preempt_disable();
+	show_regs(regs);
+	preempt_enable();
+}
+
+static int __init setup_print_fatal_signals(char *str)
+{
+	get_option (&str, &print_fatal_signals);
+
+	return 1;
+}
+
+__setup("print-fatal-signals=", setup_print_fatal_signals);
+
+int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
+			enum pid_type type)
+{
+	unsigned long flags;
+	int ret = -ESRCH;
+
+	if (lock_task_sighand(p, &flags)) {
+		ret = send_signal_locked(sig, info, p, type);
+		unlock_task_sighand(p, &flags);
+	}
+
+	return ret;
+}
+
+enum sig_handler {
+	HANDLER_CURRENT, /* If reachable use the current handler */
+	HANDLER_SIG_DFL, /* Always use SIG_DFL handler semantics */
+	HANDLER_EXIT,	 /* Only visible as the process exit code */
+};
+
+/*
+ * Force a signal that the process can't ignore: if necessary
+ * we unblock the signal and change any SIG_IGN to SIG_DFL.
+ *
+ * Note: If we unblock the signal, we always reset it to SIG_DFL,
+ * since we do not want to have a signal handler that was blocked
+ * be invoked when user space had explicitly blocked it.
+ *
+ * We don't want to have recursive SIGSEGV's etc, for example,
+ * that is why we also clear SIGNAL_UNKILLABLE.
+ */
+static int
+force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t,
+	enum sig_handler handler)
+{
+	unsigned long int flags;
+	int ret, blocked, ignored;
+	struct k_sigaction *action;
+	int sig = info->si_signo;
+
+	spin_lock_irqsave(&t->sighand->siglock, flags);
+	action = &t->sighand->action[sig-1];
+	ignored = action->sa.sa_handler == SIG_IGN;
+	blocked = sigismember(&t->blocked, sig);
+	if (blocked || ignored || (handler != HANDLER_CURRENT)) {
+		action->sa.sa_handler = SIG_DFL;
+		if (handler == HANDLER_EXIT)
+			action->sa.sa_flags |= SA_IMMUTABLE;
+		if (blocked) {
+			sigdelset(&t->blocked, sig);
+			recalc_sigpending_and_wake(t);
+		}
+	}
+	/*
+	 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
+	 * debugging to leave init killable. But HANDLER_EXIT is always fatal.
+	 */
+	if (action->sa.sa_handler == SIG_DFL &&
+	    (!t->ptrace || (handler == HANDLER_EXIT)))
+		t->signal->flags &= ~SIGNAL_UNKILLABLE;
+	ret = send_signal_locked(sig, info, t, PIDTYPE_PID);
+	spin_unlock_irqrestore(&t->sighand->siglock, flags);
+
+	return ret;
+}
+
+int force_sig_info(struct kernel_siginfo *info)
+{
+	return force_sig_info_to_task(info, current, HANDLER_CURRENT);
+}
+
+/*
+ * Nuke all other threads in the group.
+ */
+int zap_other_threads(struct task_struct *p)
+{
+	struct task_struct *t = p;
+	int count = 0;
+
+	p->signal->group_stop_count = 0;
+
+	while_each_thread(p, t) {
+		task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
+		count++;
+
+		/* Don't bother with already dead threads */
+		if (t->exit_state)
+			continue;
+		sigaddset(&t->pending.signal, SIGKILL);
+		signal_wake_up(t, 1);
+	}
+
+	return count;
+}
+
+struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
+					   unsigned long *flags)
+{
+	struct sighand_struct *sighand;
+
+	rcu_read_lock();
+	for (;;) {
+		sighand = rcu_dereference(tsk->sighand);
+		if (unlikely(sighand == NULL))
+			break;
+
+		/*
+		 * This sighand can be already freed and even reused, but
+		 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
+		 * initializes ->siglock: this slab can't go away, it has
+		 * the same object type, ->siglock can't be reinitialized.
+		 *
+		 * We need to ensure that tsk->sighand is still the same
+		 * after we take the lock, we can race with de_thread() or
+		 * __exit_signal(). In the latter case the next iteration
+		 * must see ->sighand == NULL.
+		 */
+		spin_lock_irqsave(&sighand->siglock, *flags);
+		if (likely(sighand == rcu_access_pointer(tsk->sighand)))
+			break;
+		spin_unlock_irqrestore(&sighand->siglock, *flags);
+	}
+	rcu_read_unlock();
+
+	return sighand;
+}
+
+#ifdef CONFIG_LOCKDEP
+void lockdep_assert_task_sighand_held(struct task_struct *task)
+{
+	struct sighand_struct *sighand;
+
+	rcu_read_lock();
+	sighand = rcu_dereference(task->sighand);
+	if (sighand)
+		lockdep_assert_held(&sighand->siglock);
+	else
+		WARN_ON_ONCE(1);
+	rcu_read_unlock();
+}
+#endif
+
+/*
+ * send signal info to all the members of a group
+ */
+int group_send_sig_info(int sig, struct kernel_siginfo *info,
+			struct task_struct *p, enum pid_type type)
+{
+	int ret;
+
+	rcu_read_lock();
+	ret = check_kill_permission(sig, info, p);
+	rcu_read_unlock();
+
+	if (!ret && sig)
+		ret = do_send_sig_info(sig, info, p, type);
+
+	return ret;
+}
+
+/*
+ * __kill_pgrp_info() sends a signal to a process group: this is what the tty
+ * control characters do (^C, ^Z etc)
+ * - the caller must hold at least a readlock on tasklist_lock
+ */
+int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
+{
+	struct task_struct *p = NULL;
+	int retval, success;
+
+	success = 0;
+	retval = -ESRCH;
+	do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+		int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
+		success |= !err;
+		retval = err;
+	} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+	return success ? 0 : retval;
+}
+
+int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
+{
+	int error = -ESRCH;
+	struct task_struct *p;
+
+	for (;;) {
+		rcu_read_lock();
+		p = pid_task(pid, PIDTYPE_PID);
+		if (p)
+			error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
+		rcu_read_unlock();
+		if (likely(!p || error != -ESRCH))
+			return error;
+
+		/*
+		 * The task was unhashed in between, try again.  If it
+		 * is dead, pid_task() will return NULL, if we race with
+		 * de_thread() it will find the new leader.
+		 */
+	}
+}
+
+static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
+{
+	int error;
+	rcu_read_lock();
+	error = kill_pid_info(sig, info, find_vpid(pid));
+	rcu_read_unlock();
+	return error;
+}
+
+static inline bool kill_as_cred_perm(const struct cred *cred,
+				     struct task_struct *target)
+{
+	const struct cred *pcred = __task_cred(target);
+
+	return uid_eq(cred->euid, pcred->suid) ||
+	       uid_eq(cred->euid, pcred->uid) ||
+	       uid_eq(cred->uid, pcred->suid) ||
+	       uid_eq(cred->uid, pcred->uid);
+}
+
+/*
+ * The usb asyncio usage of siginfo is wrong.  The glibc support
+ * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
+ * AKA after the generic fields:
+ *	kernel_pid_t	si_pid;
+ *	kernel_uid32_t	si_uid;
+ *	sigval_t	si_value;
+ *
+ * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
+ * after the generic fields is:
+ *	void __user 	*si_addr;
+ *
+ * This is a practical problem when there is a 64bit big endian kernel
+ * and a 32bit userspace.  As the 32bit address will encoded in the low
+ * 32bits of the pointer.  Those low 32bits will be stored at higher
+ * address than appear in a 32 bit pointer.  So userspace will not
+ * see the address it was expecting for it's completions.
+ *
+ * There is nothing in the encoding that can allow
+ * copy_siginfo_to_user32 to detect this confusion of formats, so
+ * handle this by requiring the caller of kill_pid_usb_asyncio to
+ * notice when this situration takes place and to store the 32bit
+ * pointer in sival_int, instead of sival_addr of the sigval_t addr
+ * parameter.
+ */
+int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
+			 struct pid *pid, const struct cred *cred)
+{
+	struct kernel_siginfo info;
+	struct task_struct *p;
+	unsigned long flags;
+	int ret = -EINVAL;
+
+	if (!valid_signal(sig))
+		return ret;
+
+	clear_siginfo(&info);
+	info.si_signo = sig;
+	info.si_errno = errno;
+	info.si_code = SI_ASYNCIO;
+	*((sigval_t *)&info.si_pid) = addr;
+
+	rcu_read_lock();
+	p = pid_task(pid, PIDTYPE_PID);
+	if (!p) {
+		ret = -ESRCH;
+		goto out_unlock;
+	}
+	if (!kill_as_cred_perm(cred, p)) {
+		ret = -EPERM;
+		goto out_unlock;
+	}
+	ret = security_task_kill(p, &info, sig, cred);
+	if (ret)
+		goto out_unlock;
+
+	if (sig) {
+		if (lock_task_sighand(p, &flags)) {
+			ret = __send_signal_locked(sig, &info, p, PIDTYPE_TGID, false);
+			unlock_task_sighand(p, &flags);
+		} else
+			ret = -ESRCH;
+	}
+out_unlock:
+	rcu_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
+
+/*
+ * kill_something_info() interprets pid in interesting ways just like kill(2).
+ *
+ * POSIX specifies that kill(-1,sig) is unspecified, but what we have
+ * is probably wrong.  Should make it like BSD or SYSV.
+ */
+
+static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
+{
+	int ret;
+
+	if (pid > 0)
+		return kill_proc_info(sig, info, pid);
+
+	/* -INT_MIN is undefined.  Exclude this case to avoid a UBSAN warning */
+	if (pid == INT_MIN)
+		return -ESRCH;
+
+	read_lock(&tasklist_lock);
+	if (pid != -1) {
+		ret = __kill_pgrp_info(sig, info,
+				pid ? find_vpid(-pid) : task_pgrp(current));
+	} else {
+		int retval = 0, count = 0;
+		struct task_struct * p;
+
+		for_each_process(p) {
+			if (task_pid_vnr(p) > 1 &&
+					!same_thread_group(p, current)) {
+				int err = group_send_sig_info(sig, info, p,
+							      PIDTYPE_MAX);
+				++count;
+				if (err != -EPERM)
+					retval = err;
+			}
+		}
+		ret = count ? retval : -ESRCH;
+	}
+	read_unlock(&tasklist_lock);
+
+	return ret;
+}
+
+/*
+ * These are for backward compatibility with the rest of the kernel source.
+ */
+
+int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
+{
+	/*
+	 * Make sure legacy kernel users don't send in bad values
+	 * (normal paths check this in check_kill_permission).
+	 */
+	if (!valid_signal(sig))
+		return -EINVAL;
+
+	return do_send_sig_info(sig, info, p, PIDTYPE_PID);
+}
+EXPORT_SYMBOL(send_sig_info);
+
+#define __si_special(priv) \
+	((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
+
+int
+send_sig(int sig, struct task_struct *p, int priv)
+{
+	return send_sig_info(sig, __si_special(priv), p);
+}
+EXPORT_SYMBOL(send_sig);
+
+void force_sig(int sig)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_code = SI_KERNEL;
+	info.si_pid = 0;
+	info.si_uid = 0;
+	force_sig_info(&info);
+}
+EXPORT_SYMBOL(force_sig);
+
+void force_fatal_sig(int sig)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_code = SI_KERNEL;
+	info.si_pid = 0;
+	info.si_uid = 0;
+	force_sig_info_to_task(&info, current, HANDLER_SIG_DFL);
+}
+
+void force_exit_sig(int sig)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_code = SI_KERNEL;
+	info.si_pid = 0;
+	info.si_uid = 0;
+	force_sig_info_to_task(&info, current, HANDLER_EXIT);
+}
+
+/*
+ * When things go south during signal handling, we
+ * will force a SIGSEGV. And if the signal that caused
+ * the problem was already a SIGSEGV, we'll want to
+ * make sure we don't even try to deliver the signal..
+ */
+void force_sigsegv(int sig)
+{
+	if (sig == SIGSEGV)
+		force_fatal_sig(SIGSEGV);
+	else
+		force_sig(SIGSEGV);
+}
+
+int force_sig_fault_to_task(int sig, int code, void __user *addr
+	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
+	, struct task_struct *t)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_code  = code;
+	info.si_addr  = addr;
+#ifdef __ia64__
+	info.si_imm = imm;
+	info.si_flags = flags;
+	info.si_isr = isr;
+#endif
+	return force_sig_info_to_task(&info, t, HANDLER_CURRENT);
+}
+
+int force_sig_fault(int sig, int code, void __user *addr
+	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
+{
+	return force_sig_fault_to_task(sig, code, addr
+				       ___ARCH_SI_IA64(imm, flags, isr), current);
+}
+
+int send_sig_fault(int sig, int code, void __user *addr
+	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
+	, struct task_struct *t)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_code  = code;
+	info.si_addr  = addr;
+#ifdef __ia64__
+	info.si_imm = imm;
+	info.si_flags = flags;
+	info.si_isr = isr;
+#endif
+	return send_sig_info(info.si_signo, &info, t);
+}
+
+int force_sig_mceerr(int code, void __user *addr, short lsb)
+{
+	struct kernel_siginfo info;
+
+	WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
+	clear_siginfo(&info);
+	info.si_signo = SIGBUS;
+	info.si_errno = 0;
+	info.si_code = code;
+	info.si_addr = addr;
+	info.si_addr_lsb = lsb;
+	return force_sig_info(&info);
+}
+
+int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
+{
+	struct kernel_siginfo info;
+
+	WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
+	clear_siginfo(&info);
+	info.si_signo = SIGBUS;
+	info.si_errno = 0;
+	info.si_code = code;
+	info.si_addr = addr;
+	info.si_addr_lsb = lsb;
+	return send_sig_info(info.si_signo, &info, t);
+}
+EXPORT_SYMBOL(send_sig_mceerr);
+
+int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = SIGSEGV;
+	info.si_errno = 0;
+	info.si_code  = SEGV_BNDERR;
+	info.si_addr  = addr;
+	info.si_lower = lower;
+	info.si_upper = upper;
+	return force_sig_info(&info);
+}
+
+#ifdef SEGV_PKUERR
+int force_sig_pkuerr(void __user *addr, u32 pkey)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = SIGSEGV;
+	info.si_errno = 0;
+	info.si_code  = SEGV_PKUERR;
+	info.si_addr  = addr;
+	info.si_pkey  = pkey;
+	return force_sig_info(&info);
+}
+#endif
+
+int send_sig_perf(void __user *addr, u32 type, u64 sig_data)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo     = SIGTRAP;
+	info.si_errno     = 0;
+	info.si_code      = TRAP_PERF;
+	info.si_addr      = addr;
+	info.si_perf_data = sig_data;
+	info.si_perf_type = type;
+
+	/*
+	 * Signals generated by perf events should not terminate the whole
+	 * process if SIGTRAP is blocked, however, delivering the signal
+	 * asynchronously is better than not delivering at all. But tell user
+	 * space if the signal was asynchronous, so it can clearly be
+	 * distinguished from normal synchronous ones.
+	 */
+	info.si_perf_flags = sigismember(&current->blocked, info.si_signo) ?
+				     TRAP_PERF_FLAG_ASYNC :
+				     0;
+
+	return send_sig_info(info.si_signo, &info, current);
+}
+
+/**
+ * force_sig_seccomp - signals the task to allow in-process syscall emulation
+ * @syscall: syscall number to send to userland
+ * @reason: filter-supplied reason code to send to userland (via si_errno)
+ * @force_coredump: true to trigger a coredump
+ *
+ * Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info.
+ */
+int force_sig_seccomp(int syscall, int reason, bool force_coredump)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = SIGSYS;
+	info.si_code = SYS_SECCOMP;
+	info.si_call_addr = (void __user *)KSTK_EIP(current);
+	info.si_errno = reason;
+	info.si_arch = syscall_get_arch(current);
+	info.si_syscall = syscall;
+	return force_sig_info_to_task(&info, current,
+		force_coredump ? HANDLER_EXIT : HANDLER_CURRENT);
+}
+
+/* For the crazy architectures that include trap information in
+ * the errno field, instead of an actual errno value.
+ */
+int force_sig_ptrace_errno_trap(int errno, void __user *addr)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = SIGTRAP;
+	info.si_errno = errno;
+	info.si_code  = TRAP_HWBKPT;
+	info.si_addr  = addr;
+	return force_sig_info(&info);
+}
+
+/* For the rare architectures that include trap information using
+ * si_trapno.
+ */
+int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_code  = code;
+	info.si_addr  = addr;
+	info.si_trapno = trapno;
+	return force_sig_info(&info);
+}
+
+/* For the rare architectures that include trap information using
+ * si_trapno.
+ */
+int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
+			  struct task_struct *t)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_code  = code;
+	info.si_addr  = addr;
+	info.si_trapno = trapno;
+	return send_sig_info(info.si_signo, &info, t);
+}
+
+int kill_pgrp(struct pid *pid, int sig, int priv)
+{
+	int ret;
+
+	read_lock(&tasklist_lock);
+	ret = __kill_pgrp_info(sig, __si_special(priv), pid);
+	read_unlock(&tasklist_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(kill_pgrp);
+
+int kill_pid(struct pid *pid, int sig, int priv)
+{
+	return kill_pid_info(sig, __si_special(priv), pid);
+}
+EXPORT_SYMBOL(kill_pid);
+
+/*
+ * These functions support sending signals using preallocated sigqueue
+ * structures.  This is needed "because realtime applications cannot
+ * afford to lose notifications of asynchronous events, like timer
+ * expirations or I/O completions".  In the case of POSIX Timers
+ * we allocate the sigqueue structure from the timer_create.  If this
+ * allocation fails we are able to report the failure to the application
+ * with an EAGAIN error.
+ */
+struct sigqueue *sigqueue_alloc(void)
+{
+	return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC);
+}
+
+void sigqueue_free(struct sigqueue *q)
+{
+	unsigned long flags;
+	spinlock_t *lock = &current->sighand->siglock;
+
+	BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
+	/*
+	 * We must hold ->siglock while testing q->list
+	 * to serialize with collect_signal() or with
+	 * __exit_signal()->flush_sigqueue().
+	 */
+	spin_lock_irqsave(lock, flags);
+	q->flags &= ~SIGQUEUE_PREALLOC;
+	/*
+	 * If it is queued it will be freed when dequeued,
+	 * like the "regular" sigqueue.
+	 */
+	if (!list_empty(&q->list))
+		q = NULL;
+	spin_unlock_irqrestore(lock, flags);
+
+	if (q)
+		__sigqueue_free(q);
+}
+
+int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
+{
+	int sig = q->info.si_signo;
+	struct sigpending *pending;
+	struct task_struct *t;
+	unsigned long flags;
+	int ret, result;
+
+	BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
+
+	ret = -1;
+	rcu_read_lock();
+	t = pid_task(pid, type);
+	if (!t || !likely(lock_task_sighand(t, &flags)))
+		goto ret;
+
+	ret = 1; /* the signal is ignored */
+	result = TRACE_SIGNAL_IGNORED;
+	if (!prepare_signal(sig, t, false))
+		goto out;
+
+	ret = 0;
+	if (unlikely(!list_empty(&q->list))) {
+		/*
+		 * If an SI_TIMER entry is already queue just increment
+		 * the overrun count.
+		 */
+		BUG_ON(q->info.si_code != SI_TIMER);
+		q->info.si_overrun++;
+		result = TRACE_SIGNAL_ALREADY_PENDING;
+		goto out;
+	}
+	q->info.si_overrun = 0;
+
+	signalfd_notify(t, sig);
+	pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
+	list_add_tail(&q->list, &pending->list);
+	sigaddset(&pending->signal, sig);
+	complete_signal(sig, t, type);
+	result = TRACE_SIGNAL_DELIVERED;
+out:
+	trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
+	unlock_task_sighand(t, &flags);
+ret:
+	rcu_read_unlock();
+	return ret;
+}
+
+static void do_notify_pidfd(struct task_struct *task)
+{
+	struct pid *pid;
+
+	WARN_ON(task->exit_state == 0);
+	pid = task_pid(task);
+	wake_up_all(&pid->wait_pidfd);
+}
+
+/*
+ * Let a parent know about the death of a child.
+ * For a stopped/continued status change, use do_notify_parent_cldstop instead.
+ *
+ * Returns true if our parent ignored us and so we've switched to
+ * self-reaping.
+ */
+bool do_notify_parent(struct task_struct *tsk, int sig)
+{
+	struct kernel_siginfo info;
+	unsigned long flags;
+	struct sighand_struct *psig;
+	bool autoreap = false;
+	u64 utime, stime;
+
+	WARN_ON_ONCE(sig == -1);
+
+	/* do_notify_parent_cldstop should have been called instead.  */
+	WARN_ON_ONCE(task_is_stopped_or_traced(tsk));
+
+	WARN_ON_ONCE(!tsk->ptrace &&
+	       (tsk->group_leader != tsk || !thread_group_empty(tsk)));
+
+	/* Wake up all pidfd waiters */
+	do_notify_pidfd(tsk);
+
+	if (sig != SIGCHLD) {
+		/*
+		 * This is only possible if parent == real_parent.
+		 * Check if it has changed security domain.
+		 */
+		if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
+			sig = SIGCHLD;
+	}
+
+	clear_siginfo(&info);
+	info.si_signo = sig;
+	info.si_errno = 0;
+	/*
+	 * We are under tasklist_lock here so our parent is tied to
+	 * us and cannot change.
+	 *
+	 * task_active_pid_ns will always return the same pid namespace
+	 * until a task passes through release_task.
+	 *
+	 * write_lock() currently calls preempt_disable() which is the
+	 * same as rcu_read_lock(), but according to Oleg, this is not
+	 * correct to rely on this
+	 */
+	rcu_read_lock();
+	info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
+	info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
+				       task_uid(tsk));
+	rcu_read_unlock();
+
+	task_cputime(tsk, &utime, &stime);
+	info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
+	info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
+
+	info.si_status = tsk->exit_code & 0x7f;
+	if (tsk->exit_code & 0x80)
+		info.si_code = CLD_DUMPED;
+	else if (tsk->exit_code & 0x7f)
+		info.si_code = CLD_KILLED;
+	else {
+		info.si_code = CLD_EXITED;
+		info.si_status = tsk->exit_code >> 8;
+	}
+
+	psig = tsk->parent->sighand;
+	spin_lock_irqsave(&psig->siglock, flags);
+	if (!tsk->ptrace && sig == SIGCHLD &&
+	    (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
+	     (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
+		/*
+		 * We are exiting and our parent doesn't care.  POSIX.1
+		 * defines special semantics for setting SIGCHLD to SIG_IGN
+		 * or setting the SA_NOCLDWAIT flag: we should be reaped
+		 * automatically and not left for our parent's wait4 call.
+		 * Rather than having the parent do it as a magic kind of
+		 * signal handler, we just set this to tell do_exit that we
+		 * can be cleaned up without becoming a zombie.  Note that
+		 * we still call __wake_up_parent in this case, because a
+		 * blocked sys_wait4 might now return -ECHILD.
+		 *
+		 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
+		 * is implementation-defined: we do (if you don't want
+		 * it, just use SIG_IGN instead).
+		 */
+		autoreap = true;
+		if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
+			sig = 0;
+	}
+	/*
+	 * Send with __send_signal as si_pid and si_uid are in the
+	 * parent's namespaces.
+	 */
+	if (valid_signal(sig) && sig)
+		__send_signal_locked(sig, &info, tsk->parent, PIDTYPE_TGID, false);
+	__wake_up_parent(tsk, tsk->parent);
+	spin_unlock_irqrestore(&psig->siglock, flags);
+
+	return autoreap;
+}
+
+/**
+ * do_notify_parent_cldstop - notify parent of stopped/continued state change
+ * @tsk: task reporting the state change
+ * @for_ptracer: the notification is for ptracer
+ * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
+ *
+ * Notify @tsk's parent that the stopped/continued state has changed.  If
+ * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
+ * If %true, @tsk reports to @tsk->parent which should be the ptracer.
+ *
+ * CONTEXT:
+ * Must be called with tasklist_lock at least read locked.
+ */
+static void do_notify_parent_cldstop(struct task_struct *tsk,
+				     bool for_ptracer, int why)
+{
+	struct kernel_siginfo info;
+	unsigned long flags;
+	struct task_struct *parent;
+	struct sighand_struct *sighand;
+	u64 utime, stime;
+
+	if (for_ptracer) {
+		parent = tsk->parent;
+	} else {
+		tsk = tsk->group_leader;
+		parent = tsk->real_parent;
+	}
+
+	clear_siginfo(&info);
+	info.si_signo = SIGCHLD;
+	info.si_errno = 0;
+	/*
+	 * see comment in do_notify_parent() about the following 4 lines
+	 */
+	rcu_read_lock();
+	info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
+	info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
+	rcu_read_unlock();
+
+	task_cputime(tsk, &utime, &stime);
+	info.si_utime = nsec_to_clock_t(utime);
+	info.si_stime = nsec_to_clock_t(stime);
+
+ 	info.si_code = why;
+ 	switch (why) {
+ 	case CLD_CONTINUED:
+ 		info.si_status = SIGCONT;
+ 		break;
+ 	case CLD_STOPPED:
+ 		info.si_status = tsk->signal->group_exit_code & 0x7f;
+ 		break;
+ 	case CLD_TRAPPED:
+ 		info.si_status = tsk->exit_code & 0x7f;
+ 		break;
+ 	default:
+ 		BUG();
+ 	}
+
+	sighand = parent->sighand;
+	spin_lock_irqsave(&sighand->siglock, flags);
+	if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
+	    !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
+		send_signal_locked(SIGCHLD, &info, parent, PIDTYPE_TGID);
+	/*
+	 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
+	 */
+	__wake_up_parent(tsk, parent);
+	spin_unlock_irqrestore(&sighand->siglock, flags);
+}
+
+/*
+ * This must be called with current->sighand->siglock held.
+ *
+ * This should be the path for all ptrace stops.
+ * We always set current->last_siginfo while stopped here.
+ * That makes it a way to test a stopped process for
+ * being ptrace-stopped vs being job-control-stopped.
+ *
+ * Returns the signal the ptracer requested the code resume
+ * with.  If the code did not stop because the tracer is gone,
+ * the stop signal remains unchanged unless clear_code.
+ */
+static int ptrace_stop(int exit_code, int why, unsigned long message,
+		       kernel_siginfo_t *info)
+	__releases(&current->sighand->siglock)
+	__acquires(&current->sighand->siglock)
+{
+	bool gstop_done = false;
+
+	if (arch_ptrace_stop_needed()) {
+		/*
+		 * The arch code has something special to do before a
+		 * ptrace stop.  This is allowed to block, e.g. for faults
+		 * on user stack pages.  We can't keep the siglock while
+		 * calling arch_ptrace_stop, so we must release it now.
+		 * To preserve proper semantics, we must do this before
+		 * any signal bookkeeping like checking group_stop_count.
+		 */
+		spin_unlock_irq(&current->sighand->siglock);
+		arch_ptrace_stop();
+		spin_lock_irq(&current->sighand->siglock);
+	}
+
+	/*
+	 * After this point ptrace_signal_wake_up or signal_wake_up
+	 * will clear TASK_TRACED if ptrace_unlink happens or a fatal
+	 * signal comes in.  Handle previous ptrace_unlinks and fatal
+	 * signals here to prevent ptrace_stop sleeping in schedule.
+	 */
+	if (!current->ptrace || __fatal_signal_pending(current))
+		return exit_code;
+
+	set_special_state(TASK_TRACED);
+	current->jobctl |= JOBCTL_TRACED;
+
+	/*
+	 * We're committing to trapping.  TRACED should be visible before
+	 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
+	 * Also, transition to TRACED and updates to ->jobctl should be
+	 * atomic with respect to siglock and should be done after the arch
+	 * hook as siglock is released and regrabbed across it.
+	 *
+	 *     TRACER				    TRACEE
+	 *
+	 *     ptrace_attach()
+	 * [L]   wait_on_bit(JOBCTL_TRAPPING)	[S] set_special_state(TRACED)
+	 *     do_wait()
+	 *       set_current_state()                smp_wmb();
+	 *       ptrace_do_wait()
+	 *         wait_task_stopped()
+	 *           task_stopped_code()
+	 * [L]         task_is_traced()		[S] task_clear_jobctl_trapping();
+	 */
+	smp_wmb();
+
+	current->ptrace_message = message;
+	current->last_siginfo = info;
+	current->exit_code = exit_code;
+
+	/*
+	 * If @why is CLD_STOPPED, we're trapping to participate in a group
+	 * stop.  Do the bookkeeping.  Note that if SIGCONT was delievered
+	 * across siglock relocks since INTERRUPT was scheduled, PENDING
+	 * could be clear now.  We act as if SIGCONT is received after
+	 * TASK_TRACED is entered - ignore it.
+	 */
+	if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
+		gstop_done = task_participate_group_stop(current);
+
+	/* any trap clears pending STOP trap, STOP trap clears NOTIFY */
+	task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
+	if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
+		task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
+
+	/* entering a trap, clear TRAPPING */
+	task_clear_jobctl_trapping(current);
+
+	spin_unlock_irq(&current->sighand->siglock);
+	read_lock(&tasklist_lock);
+	/*
+	 * Notify parents of the stop.
+	 *
+	 * While ptraced, there are two parents - the ptracer and
+	 * the real_parent of the group_leader.  The ptracer should
+	 * know about every stop while the real parent is only
+	 * interested in the completion of group stop.  The states
+	 * for the two don't interact with each other.  Notify
+	 * separately unless they're gonna be duplicates.
+	 */
+	if (current->ptrace)
+		do_notify_parent_cldstop(current, true, why);
+	if (gstop_done && (!current->ptrace || ptrace_reparented(current)))
+		do_notify_parent_cldstop(current, false, why);
+
+	/*
+	 * Don't want to allow preemption here, because
+	 * sys_ptrace() needs this task to be inactive.
+	 *
+	 * XXX: implement read_unlock_no_resched().
+	 */
+	preempt_disable();
+	read_unlock(&tasklist_lock);
+	cgroup_enter_frozen();
+	preempt_enable_no_resched();
+	schedule();
+	cgroup_leave_frozen(true);
+
+	/*
+	 * We are back.  Now reacquire the siglock before touching
+	 * last_siginfo, so that we are sure to have synchronized with
+	 * any signal-sending on another CPU that wants to examine it.
+	 */
+	spin_lock_irq(&current->sighand->siglock);
+	exit_code = current->exit_code;
+	current->last_siginfo = NULL;
+	current->ptrace_message = 0;
+	current->exit_code = 0;
+
+	/* LISTENING can be set only during STOP traps, clear it */
+	current->jobctl &= ~(JOBCTL_LISTENING | JOBCTL_PTRACE_FROZEN);
+
+	/*
+	 * Queued signals ignored us while we were stopped for tracing.
+	 * So check for any that we should take before resuming user mode.
+	 * This sets TIF_SIGPENDING, but never clears it.
+	 */
+	recalc_sigpending_tsk(current);
+	return exit_code;
+}
+
+static int ptrace_do_notify(int signr, int exit_code, int why, unsigned long message)
+{
+	kernel_siginfo_t info;
+
+	clear_siginfo(&info);
+	info.si_signo = signr;
+	info.si_code = exit_code;
+	info.si_pid = task_pid_vnr(current);
+	info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
+
+	/* Let the debugger run.  */
+	return ptrace_stop(exit_code, why, message, &info);
+}
+
+int ptrace_notify(int exit_code, unsigned long message)
+{
+	int signr;
+
+	BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
+	if (unlikely(task_work_pending(current)))
+		task_work_run();
+
+	spin_lock_irq(&current->sighand->siglock);
+	signr = ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED, message);
+	spin_unlock_irq(&current->sighand->siglock);
+	return signr;
+}
+
+/**
+ * do_signal_stop - handle group stop for SIGSTOP and other stop signals
+ * @signr: signr causing group stop if initiating
+ *
+ * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
+ * and participate in it.  If already set, participate in the existing
+ * group stop.  If participated in a group stop (and thus slept), %true is
+ * returned with siglock released.
+ *
+ * If ptraced, this function doesn't handle stop itself.  Instead,
+ * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
+ * untouched.  The caller must ensure that INTERRUPT trap handling takes
+ * places afterwards.
+ *
+ * CONTEXT:
+ * Must be called with @current->sighand->siglock held, which is released
+ * on %true return.
+ *
+ * RETURNS:
+ * %false if group stop is already cancelled or ptrace trap is scheduled.
+ * %true if participated in group stop.
+ */
+static bool do_signal_stop(int signr)
+	__releases(&current->sighand->siglock)
+{
+	struct signal_struct *sig = current->signal;
+
+	if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
+		unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
+		struct task_struct *t;
+
+		/* signr will be recorded in task->jobctl for retries */
+		WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
+
+		if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
+		    unlikely(sig->flags & SIGNAL_GROUP_EXIT) ||
+		    unlikely(sig->group_exec_task))
+			return false;
+		/*
+		 * There is no group stop already in progress.  We must
+		 * initiate one now.
+		 *
+		 * While ptraced, a task may be resumed while group stop is
+		 * still in effect and then receive a stop signal and
+		 * initiate another group stop.  This deviates from the
+		 * usual behavior as two consecutive stop signals can't
+		 * cause two group stops when !ptraced.  That is why we
+		 * also check !task_is_stopped(t) below.
+		 *
+		 * The condition can be distinguished by testing whether
+		 * SIGNAL_STOP_STOPPED is already set.  Don't generate
+		 * group_exit_code in such case.
+		 *
+		 * This is not necessary for SIGNAL_STOP_CONTINUED because
+		 * an intervening stop signal is required to cause two
+		 * continued events regardless of ptrace.
+		 */
+		if (!(sig->flags & SIGNAL_STOP_STOPPED))
+			sig->group_exit_code = signr;
+
+		sig->group_stop_count = 0;
+
+		if (task_set_jobctl_pending(current, signr | gstop))
+			sig->group_stop_count++;
+
+		t = current;
+		while_each_thread(current, t) {
+			/*
+			 * Setting state to TASK_STOPPED for a group
+			 * stop is always done with the siglock held,
+			 * so this check has no races.
+			 */
+			if (!task_is_stopped(t) &&
+			    task_set_jobctl_pending(t, signr | gstop)) {
+				sig->group_stop_count++;
+				if (likely(!(t->ptrace & PT_SEIZED)))
+					signal_wake_up(t, 0);
+				else
+					ptrace_trap_notify(t);
+			}
+		}
+	}
+
+	if (likely(!current->ptrace)) {
+		int notify = 0;
+
+		/*
+		 * If there are no other threads in the group, or if there
+		 * is a group stop in progress and we are the last to stop,
+		 * report to the parent.
+		 */
+		if (task_participate_group_stop(current))
+			notify = CLD_STOPPED;
+
+		current->jobctl |= JOBCTL_STOPPED;
+		set_special_state(TASK_STOPPED);
+		spin_unlock_irq(&current->sighand->siglock);
+
+		/*
+		 * Notify the parent of the group stop completion.  Because
+		 * we're not holding either the siglock or tasklist_lock
+		 * here, ptracer may attach inbetween; however, this is for
+		 * group stop and should always be delivered to the real
+		 * parent of the group leader.  The new ptracer will get
+		 * its notification when this task transitions into
+		 * TASK_TRACED.
+		 */
+		if (notify) {
+			read_lock(&tasklist_lock);
+			do_notify_parent_cldstop(current, false, notify);
+			read_unlock(&tasklist_lock);
+		}
+
+		/* Now we don't run again until woken by SIGCONT or SIGKILL */
+		cgroup_enter_frozen();
+		schedule();
+		return true;
+	} else {
+		/*
+		 * While ptraced, group stop is handled by STOP trap.
+		 * Schedule it and let the caller deal with it.
+		 */
+		task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
+		return false;
+	}
+}
+
+/**
+ * do_jobctl_trap - take care of ptrace jobctl traps
+ *
+ * When PT_SEIZED, it's used for both group stop and explicit
+ * SEIZE/INTERRUPT traps.  Both generate PTRACE_EVENT_STOP trap with
+ * accompanying siginfo.  If stopped, lower eight bits of exit_code contain
+ * the stop signal; otherwise, %SIGTRAP.
+ *
+ * When !PT_SEIZED, it's used only for group stop trap with stop signal
+ * number as exit_code and no siginfo.
+ *
+ * CONTEXT:
+ * Must be called with @current->sighand->siglock held, which may be
+ * released and re-acquired before returning with intervening sleep.
+ */
+static void do_jobctl_trap(void)
+{
+	struct signal_struct *signal = current->signal;
+	int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
+
+	if (current->ptrace & PT_SEIZED) {
+		if (!signal->group_stop_count &&
+		    !(signal->flags & SIGNAL_STOP_STOPPED))
+			signr = SIGTRAP;
+		WARN_ON_ONCE(!signr);
+		ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
+				 CLD_STOPPED, 0);
+	} else {
+		WARN_ON_ONCE(!signr);
+		ptrace_stop(signr, CLD_STOPPED, 0, NULL);
+	}
+}
+
+/**
+ * do_freezer_trap - handle the freezer jobctl trap
+ *
+ * Puts the task into frozen state, if only the task is not about to quit.
+ * In this case it drops JOBCTL_TRAP_FREEZE.
+ *
+ * CONTEXT:
+ * Must be called with @current->sighand->siglock held,
+ * which is always released before returning.
+ */
+static void do_freezer_trap(void)
+	__releases(&current->sighand->siglock)
+{
+	/*
+	 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
+	 * let's make another loop to give it a chance to be handled.
+	 * In any case, we'll return back.
+	 */
+	if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
+	     JOBCTL_TRAP_FREEZE) {
+		spin_unlock_irq(&current->sighand->siglock);
+		return;
+	}
+
+	/*
+	 * Now we're sure that there is no pending fatal signal and no
+	 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
+	 * immediately (if there is a non-fatal signal pending), and
+	 * put the task into sleep.
+	 */
+	__set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
+	clear_thread_flag(TIF_SIGPENDING);
+	spin_unlock_irq(&current->sighand->siglock);
+	cgroup_enter_frozen();
+	schedule();
+}
+
+static int ptrace_signal(int signr, kernel_siginfo_t *info, enum pid_type type)
+{
+	/*
+	 * We do not check sig_kernel_stop(signr) but set this marker
+	 * unconditionally because we do not know whether debugger will
+	 * change signr. This flag has no meaning unless we are going
+	 * to stop after return from ptrace_stop(). In this case it will
+	 * be checked in do_signal_stop(), we should only stop if it was
+	 * not cleared by SIGCONT while we were sleeping. See also the
+	 * comment in dequeue_signal().
+	 */
+	current->jobctl |= JOBCTL_STOP_DEQUEUED;
+	signr = ptrace_stop(signr, CLD_TRAPPED, 0, info);
+
+	/* We're back.  Did the debugger cancel the sig?  */
+	if (signr == 0)
+		return signr;
+
+	/*
+	 * Update the siginfo structure if the signal has
+	 * changed.  If the debugger wanted something
+	 * specific in the siginfo structure then it should
+	 * have updated *info via PTRACE_SETSIGINFO.
+	 */
+	if (signr != info->si_signo) {
+		clear_siginfo(info);
+		info->si_signo = signr;
+		info->si_errno = 0;
+		info->si_code = SI_USER;
+		rcu_read_lock();
+		info->si_pid = task_pid_vnr(current->parent);
+		info->si_uid = from_kuid_munged(current_user_ns(),
+						task_uid(current->parent));
+		rcu_read_unlock();
+	}
+
+	/* If the (new) signal is now blocked, requeue it.  */
+	if (sigismember(&current->blocked, signr) ||
+	    fatal_signal_pending(current)) {
+		send_signal_locked(signr, info, current, type);
+		signr = 0;
+	}
+
+	return signr;
+}
+
+static void hide_si_addr_tag_bits(struct ksignal *ksig)
+{
+	switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
+	case SIL_FAULT:
+	case SIL_FAULT_TRAPNO:
+	case SIL_FAULT_MCEERR:
+	case SIL_FAULT_BNDERR:
+	case SIL_FAULT_PKUERR:
+	case SIL_FAULT_PERF_EVENT:
+		ksig->info.si_addr = arch_untagged_si_addr(
+			ksig->info.si_addr, ksig->sig, ksig->info.si_code);
+		break;
+	case SIL_KILL:
+	case SIL_TIMER:
+	case SIL_POLL:
+	case SIL_CHLD:
+	case SIL_RT:
+	case SIL_SYS:
+		break;
+	}
+}
+
+bool get_signal(struct ksignal *ksig)
+{
+	struct sighand_struct *sighand = current->sighand;
+	struct signal_struct *signal = current->signal;
+	int signr;
+
+	clear_notify_signal();
+	if (unlikely(task_work_pending(current)))
+		task_work_run();
+
+	if (!task_sigpending(current))
+		return false;
+
+	if (unlikely(uprobe_deny_signal()))
+		return false;
+
+	/*
+	 * Do this once, we can't return to user-mode if freezing() == T.
+	 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
+	 * thus do not need another check after return.
+	 */
+	try_to_freeze();
+
+relock:
+	spin_lock_irq(&sighand->siglock);
+
+	/*
+	 * Every stopped thread goes here after wakeup. Check to see if
+	 * we should notify the parent, prepare_signal(SIGCONT) encodes
+	 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
+	 */
+	if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
+		int why;
+
+		if (signal->flags & SIGNAL_CLD_CONTINUED)
+			why = CLD_CONTINUED;
+		else
+			why = CLD_STOPPED;
+
+		signal->flags &= ~SIGNAL_CLD_MASK;
+
+		spin_unlock_irq(&sighand->siglock);
+
+		/*
+		 * Notify the parent that we're continuing.  This event is
+		 * always per-process and doesn't make whole lot of sense
+		 * for ptracers, who shouldn't consume the state via
+		 * wait(2) either, but, for backward compatibility, notify
+		 * the ptracer of the group leader too unless it's gonna be
+		 * a duplicate.
+		 */
+		read_lock(&tasklist_lock);
+		do_notify_parent_cldstop(current, false, why);
+
+		if (ptrace_reparented(current->group_leader))
+			do_notify_parent_cldstop(current->group_leader,
+						true, why);
+		read_unlock(&tasklist_lock);
+
+		goto relock;
+	}
+
+	for (;;) {
+		struct k_sigaction *ka;
+		enum pid_type type;
+
+		/* Has this task already been marked for death? */
+		if ((signal->flags & SIGNAL_GROUP_EXIT) ||
+		     signal->group_exec_task) {
+			ksig->info.si_signo = signr = SIGKILL;
+			sigdelset(&current->pending.signal, SIGKILL);
+			trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
+				&sighand->action[SIGKILL - 1]);
+			recalc_sigpending();
+			goto fatal;
+		}
+
+		if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
+		    do_signal_stop(0))
+			goto relock;
+
+		if (unlikely(current->jobctl &
+			     (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
+			if (current->jobctl & JOBCTL_TRAP_MASK) {
+				do_jobctl_trap();
+				spin_unlock_irq(&sighand->siglock);
+			} else if (current->jobctl & JOBCTL_TRAP_FREEZE)
+				do_freezer_trap();
+
+			goto relock;
+		}
+
+		/*
+		 * If the task is leaving the frozen state, let's update
+		 * cgroup counters and reset the frozen bit.
+		 */
+		if (unlikely(cgroup_task_frozen(current))) {
+			spin_unlock_irq(&sighand->siglock);
+			cgroup_leave_frozen(false);
+			goto relock;
+		}
+
+		/*
+		 * Signals generated by the execution of an instruction
+		 * need to be delivered before any other pending signals
+		 * so that the instruction pointer in the signal stack
+		 * frame points to the faulting instruction.
+		 */
+		type = PIDTYPE_PID;
+		signr = dequeue_synchronous_signal(&ksig->info);
+		if (!signr)
+			signr = dequeue_signal(current, &current->blocked,
+					       &ksig->info, &type);
+
+		if (!signr)
+			break; /* will return 0 */
+
+		if (unlikely(current->ptrace) && (signr != SIGKILL) &&
+		    !(sighand->action[signr -1].sa.sa_flags & SA_IMMUTABLE)) {
+			signr = ptrace_signal(signr, &ksig->info, type);
+			if (!signr)
+				continue;
+		}
+
+		ka = &sighand->action[signr-1];
+
+		/* Trace actually delivered signals. */
+		trace_signal_deliver(signr, &ksig->info, ka);
+
+		if (ka->sa.sa_handler == SIG_IGN) /* Do nothing.  */
+			continue;
+		if (ka->sa.sa_handler != SIG_DFL) {
+			/* Run the handler.  */
+			ksig->ka = *ka;
+
+			if (ka->sa.sa_flags & SA_ONESHOT)
+				ka->sa.sa_handler = SIG_DFL;
+
+			break; /* will return non-zero "signr" value */
+		}
+
+		/*
+		 * Now we are doing the default action for this signal.
+		 */
+		if (sig_kernel_ignore(signr)) /* Default is nothing. */
+			continue;
+
+		/*
+		 * Global init gets no signals it doesn't want.
+		 * Container-init gets no signals it doesn't want from same
+		 * container.
+		 *
+		 * Note that if global/container-init sees a sig_kernel_only()
+		 * signal here, the signal must have been generated internally
+		 * or must have come from an ancestor namespace. In either
+		 * case, the signal cannot be dropped.
+		 */
+		if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
+				!sig_kernel_only(signr))
+			continue;
+
+		if (sig_kernel_stop(signr)) {
+			/*
+			 * The default action is to stop all threads in
+			 * the thread group.  The job control signals
+			 * do nothing in an orphaned pgrp, but SIGSTOP
+			 * always works.  Note that siglock needs to be
+			 * dropped during the call to is_orphaned_pgrp()
+			 * because of lock ordering with tasklist_lock.
+			 * This allows an intervening SIGCONT to be posted.
+			 * We need to check for that and bail out if necessary.
+			 */
+			if (signr != SIGSTOP) {
+				spin_unlock_irq(&sighand->siglock);
+
+				/* signals can be posted during this window */
+
+				if (is_current_pgrp_orphaned())
+					goto relock;
+
+				spin_lock_irq(&sighand->siglock);
+			}
+
+			if (likely(do_signal_stop(ksig->info.si_signo))) {
+				/* It released the siglock.  */
+				goto relock;
+			}
+
+			/*
+			 * We didn't actually stop, due to a race
+			 * with SIGCONT or something like that.
+			 */
+			continue;
+		}
+
+	fatal:
+		spin_unlock_irq(&sighand->siglock);
+		if (unlikely(cgroup_task_frozen(current)))
+			cgroup_leave_frozen(true);
+
+		/*
+		 * Anything else is fatal, maybe with a core dump.
+		 */
+		current->flags |= PF_SIGNALED;
+
+		if (sig_kernel_coredump(signr)) {
+			if (print_fatal_signals)
+				print_fatal_signal(ksig->info.si_signo);
+			proc_coredump_connector(current);
+			/*
+			 * If it was able to dump core, this kills all
+			 * other threads in the group and synchronizes with
+			 * their demise.  If we lost the race with another
+			 * thread getting here, it set group_exit_code
+			 * first and our do_group_exit call below will use
+			 * that value and ignore the one we pass it.
+			 */
+			do_coredump(&ksig->info);
+		}
+
+		/*
+		 * PF_IO_WORKER threads will catch and exit on fatal signals
+		 * themselves. They have cleanup that must be performed, so
+		 * we cannot call do_exit() on their behalf.
+		 */
+		if (current->flags & PF_IO_WORKER)
+			goto out;
+
+		/*
+		 * Death signals, no core dump.
+		 */
+		do_group_exit(ksig->info.si_signo);
+		/* NOTREACHED */
+	}
+	spin_unlock_irq(&sighand->siglock);
+out:
+	ksig->sig = signr;
+
+	if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
+		hide_si_addr_tag_bits(ksig);
+
+	return ksig->sig > 0;
+}
+
+/**
+ * signal_delivered - called after signal delivery to update blocked signals
+ * @ksig:		kernel signal struct
+ * @stepping:		nonzero if debugger single-step or block-step in use
+ *
+ * This function should be called when a signal has successfully been
+ * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
+ * is always blocked), and the signal itself is blocked unless %SA_NODEFER
+ * is set in @ksig->ka.sa.sa_flags.  Tracing is notified.
+ */
+static void signal_delivered(struct ksignal *ksig, int stepping)
+{
+	sigset_t blocked;
+
+	/* A signal was successfully delivered, and the
+	   saved sigmask was stored on the signal frame,
+	   and will be restored by sigreturn.  So we can
+	   simply clear the restore sigmask flag.  */
+	clear_restore_sigmask();
+
+	sigorsets(&blocked, &current->blocked, &ksig->ka.sa.sa_mask);
+	if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
+		sigaddset(&blocked, ksig->sig);
+	set_current_blocked(&blocked);
+	if (current->sas_ss_flags & SS_AUTODISARM)
+		sas_ss_reset(current);
+	if (stepping)
+		ptrace_notify(SIGTRAP, 0);
+}
+
+void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
+{
+	if (failed)
+		force_sigsegv(ksig->sig);
+	else
+		signal_delivered(ksig, stepping);
+}
+
+/*
+ * It could be that complete_signal() picked us to notify about the
+ * group-wide signal. Other threads should be notified now to take
+ * the shared signals in @which since we will not.
+ */
+static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
+{
+	sigset_t retarget;
+	struct task_struct *t;
+
+	sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
+	if (sigisemptyset(&retarget))
+		return;
+
+	t = tsk;
+	while_each_thread(tsk, t) {
+		if (t->flags & PF_EXITING)
+			continue;
+
+		if (!has_pending_signals(&retarget, &t->blocked))
+			continue;
+		/* Remove the signals this thread can handle. */
+		sigandsets(&retarget, &retarget, &t->blocked);
+
+		if (!task_sigpending(t))
+			signal_wake_up(t, 0);
+
+		if (sigisemptyset(&retarget))
+			break;
+	}
+}
+
+void exit_signals(struct task_struct *tsk)
+{
+	int group_stop = 0;
+	sigset_t unblocked;
+
+	/*
+	 * @tsk is about to have PF_EXITING set - lock out users which
+	 * expect stable threadgroup.
+	 */
+	cgroup_threadgroup_change_begin(tsk);
+
+	if (thread_group_empty(tsk) || (tsk->signal->flags & SIGNAL_GROUP_EXIT)) {
+		tsk->flags |= PF_EXITING;
+		cgroup_threadgroup_change_end(tsk);
+		return;
+	}
+
+	spin_lock_irq(&tsk->sighand->siglock);
+	/*
+	 * From now this task is not visible for group-wide signals,
+	 * see wants_signal(), do_signal_stop().
+	 */
+	tsk->flags |= PF_EXITING;
+
+	cgroup_threadgroup_change_end(tsk);
+
+	if (!task_sigpending(tsk))
+		goto out;
+
+	unblocked = tsk->blocked;
+	signotset(&unblocked);
+	retarget_shared_pending(tsk, &unblocked);
+
+	if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
+	    task_participate_group_stop(tsk))
+		group_stop = CLD_STOPPED;
+out:
+	spin_unlock_irq(&tsk->sighand->siglock);
+
+	/*
+	 * If group stop has completed, deliver the notification.  This
+	 * should always go to the real parent of the group leader.
+	 */
+	if (unlikely(group_stop)) {
+		read_lock(&tasklist_lock);
+		do_notify_parent_cldstop(tsk, false, group_stop);
+		read_unlock(&tasklist_lock);
+	}
+}
+
+/*
+ * System call entry points.
+ */
+
+/**
+ *  sys_restart_syscall - restart a system call
+ */
+SYSCALL_DEFINE0(restart_syscall)
+{
+	struct restart_block *restart = &current->restart_block;
+	return restart->fn(restart);
+}
+
+long do_no_restart_syscall(struct restart_block *param)
+{
+	return -EINTR;
+}
+
+static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
+{
+	if (task_sigpending(tsk) && !thread_group_empty(tsk)) {
+		sigset_t newblocked;
+		/* A set of now blocked but previously unblocked signals. */
+		sigandnsets(&newblocked, newset, &current->blocked);
+		retarget_shared_pending(tsk, &newblocked);
+	}
+	tsk->blocked = *newset;
+	recalc_sigpending();
+}
+
+/**
+ * set_current_blocked - change current->blocked mask
+ * @newset: new mask
+ *
+ * It is wrong to change ->blocked directly, this helper should be used
+ * to ensure the process can't miss a shared signal we are going to block.
+ */
+void set_current_blocked(sigset_t *newset)
+{
+	sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
+	__set_current_blocked(newset);
+}
+
+void __set_current_blocked(const sigset_t *newset)
+{
+	struct task_struct *tsk = current;
+
+	/*
+	 * In case the signal mask hasn't changed, there is nothing we need
+	 * to do. The current->blocked shouldn't be modified by other task.
+	 */
+	if (sigequalsets(&tsk->blocked, newset))
+		return;
+
+	spin_lock_irq(&tsk->sighand->siglock);
+	__set_task_blocked(tsk, newset);
+	spin_unlock_irq(&tsk->sighand->siglock);
+}
+
+/*
+ * This is also useful for kernel threads that want to temporarily
+ * (or permanently) block certain signals.
+ *
+ * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
+ * interface happily blocks "unblockable" signals like SIGKILL
+ * and friends.
+ */
+int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
+{
+	struct task_struct *tsk = current;
+	sigset_t newset;
+
+	/* Lockless, only current can change ->blocked, never from irq */
+	if (oldset)
+		*oldset = tsk->blocked;
+
+	switch (how) {
+	case SIG_BLOCK:
+		sigorsets(&newset, &tsk->blocked, set);
+		break;
+	case SIG_UNBLOCK:
+		sigandnsets(&newset, &tsk->blocked, set);
+		break;
+	case SIG_SETMASK:
+		newset = *set;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	__set_current_blocked(&newset);
+	return 0;
+}
+EXPORT_SYMBOL(sigprocmask);
+
+/*
+ * The api helps set app-provided sigmasks.
+ *
+ * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
+ * epoll_pwait where a new sigmask is passed from userland for the syscalls.
+ *
+ * Note that it does set_restore_sigmask() in advance, so it must be always
+ * paired with restore_saved_sigmask_unless() before return from syscall.
+ */
+int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
+{
+	sigset_t kmask;
+
+	if (!umask)
+		return 0;
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+	if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
+		return -EFAULT;
+
+	set_restore_sigmask();
+	current->saved_sigmask = current->blocked;
+	set_current_blocked(&kmask);
+
+	return 0;
+}
+
+#ifdef CONFIG_COMPAT
+int set_compat_user_sigmask(const compat_sigset_t __user *umask,
+			    size_t sigsetsize)
+{
+	sigset_t kmask;
+
+	if (!umask)
+		return 0;
+	if (sigsetsize != sizeof(compat_sigset_t))
+		return -EINVAL;
+	if (get_compat_sigset(&kmask, umask))
+		return -EFAULT;
+
+	set_restore_sigmask();
+	current->saved_sigmask = current->blocked;
+	set_current_blocked(&kmask);
+
+	return 0;
+}
+#endif
+
+/**
+ *  sys_rt_sigprocmask - change the list of currently blocked signals
+ *  @how: whether to add, remove, or set signals
+ *  @nset: stores pending signals
+ *  @oset: previous value of signal mask if non-null
+ *  @sigsetsize: size of sigset_t type
+ */
+SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
+		sigset_t __user *, oset, size_t, sigsetsize)
+{
+	sigset_t old_set, new_set;
+	int error;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	old_set = current->blocked;
+
+	if (nset) {
+		if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
+			return -EFAULT;
+		sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
+
+		error = sigprocmask(how, &new_set, NULL);
+		if (error)
+			return error;
+	}
+
+	if (oset) {
+		if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
+		compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
+{
+	sigset_t old_set = current->blocked;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	if (nset) {
+		sigset_t new_set;
+		int error;
+		if (get_compat_sigset(&new_set, nset))
+			return -EFAULT;
+		sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
+
+		error = sigprocmask(how, &new_set, NULL);
+		if (error)
+			return error;
+	}
+	return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
+}
+#endif
+
+static void do_sigpending(sigset_t *set)
+{
+	spin_lock_irq(&current->sighand->siglock);
+	sigorsets(set, &current->pending.signal,
+		  &current->signal->shared_pending.signal);
+	spin_unlock_irq(&current->sighand->siglock);
+
+	/* Outside the lock because only this thread touches it.  */
+	sigandsets(set, &current->blocked, set);
+}
+
+/**
+ *  sys_rt_sigpending - examine a pending signal that has been raised
+ *			while blocked
+ *  @uset: stores pending signals
+ *  @sigsetsize: size of sigset_t type or larger
+ */
+SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
+{
+	sigset_t set;
+
+	if (sigsetsize > sizeof(*uset))
+		return -EINVAL;
+
+	do_sigpending(&set);
+
+	if (copy_to_user(uset, &set, sigsetsize))
+		return -EFAULT;
+
+	return 0;
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
+		compat_size_t, sigsetsize)
+{
+	sigset_t set;
+
+	if (sigsetsize > sizeof(*uset))
+		return -EINVAL;
+
+	do_sigpending(&set);
+
+	return put_compat_sigset(uset, &set, sigsetsize);
+}
+#endif
+
+static const struct {
+	unsigned char limit, layout;
+} sig_sicodes[] = {
+	[SIGILL]  = { NSIGILL,  SIL_FAULT },
+	[SIGFPE]  = { NSIGFPE,  SIL_FAULT },
+	[SIGSEGV] = { NSIGSEGV, SIL_FAULT },
+	[SIGBUS]  = { NSIGBUS,  SIL_FAULT },
+	[SIGTRAP] = { NSIGTRAP, SIL_FAULT },
+#if defined(SIGEMT)
+	[SIGEMT]  = { NSIGEMT,  SIL_FAULT },
+#endif
+	[SIGCHLD] = { NSIGCHLD, SIL_CHLD },
+	[SIGPOLL] = { NSIGPOLL, SIL_POLL },
+	[SIGSYS]  = { NSIGSYS,  SIL_SYS },
+};
+
+static bool known_siginfo_layout(unsigned sig, int si_code)
+{
+	if (si_code == SI_KERNEL)
+		return true;
+	else if ((si_code > SI_USER)) {
+		if (sig_specific_sicodes(sig)) {
+			if (si_code <= sig_sicodes[sig].limit)
+				return true;
+		}
+		else if (si_code <= NSIGPOLL)
+			return true;
+	}
+	else if (si_code >= SI_DETHREAD)
+		return true;
+	else if (si_code == SI_ASYNCNL)
+		return true;
+	return false;
+}
+
+enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
+{
+	enum siginfo_layout layout = SIL_KILL;
+	if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
+		if ((sig < ARRAY_SIZE(sig_sicodes)) &&
+		    (si_code <= sig_sicodes[sig].limit)) {
+			layout = sig_sicodes[sig].layout;
+			/* Handle the exceptions */
+			if ((sig == SIGBUS) &&
+			    (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
+				layout = SIL_FAULT_MCEERR;
+			else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
+				layout = SIL_FAULT_BNDERR;
+#ifdef SEGV_PKUERR
+			else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
+				layout = SIL_FAULT_PKUERR;
+#endif
+			else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
+				layout = SIL_FAULT_PERF_EVENT;
+			else if (IS_ENABLED(CONFIG_SPARC) &&
+				 (sig == SIGILL) && (si_code == ILL_ILLTRP))
+				layout = SIL_FAULT_TRAPNO;
+			else if (IS_ENABLED(CONFIG_ALPHA) &&
+				 ((sig == SIGFPE) ||
+				  ((sig == SIGTRAP) && (si_code == TRAP_UNK))))
+				layout = SIL_FAULT_TRAPNO;
+		}
+		else if (si_code <= NSIGPOLL)
+			layout = SIL_POLL;
+	} else {
+		if (si_code == SI_TIMER)
+			layout = SIL_TIMER;
+		else if (si_code == SI_SIGIO)
+			layout = SIL_POLL;
+		else if (si_code < 0)
+			layout = SIL_RT;
+	}
+	return layout;
+}
+
+static inline char __user *si_expansion(const siginfo_t __user *info)
+{
+	return ((char __user *)info) + sizeof(struct kernel_siginfo);
+}
+
+int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
+{
+	char __user *expansion = si_expansion(to);
+	if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
+		return -EFAULT;
+	if (clear_user(expansion, SI_EXPANSION_SIZE))
+		return -EFAULT;
+	return 0;
+}
+
+static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
+				       const siginfo_t __user *from)
+{
+	if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
+		char __user *expansion = si_expansion(from);
+		char buf[SI_EXPANSION_SIZE];
+		int i;
+		/*
+		 * An unknown si_code might need more than
+		 * sizeof(struct kernel_siginfo) bytes.  Verify all of the
+		 * extra bytes are 0.  This guarantees copy_siginfo_to_user
+		 * will return this data to userspace exactly.
+		 */
+		if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
+			return -EFAULT;
+		for (i = 0; i < SI_EXPANSION_SIZE; i++) {
+			if (buf[i] != 0)
+				return -E2BIG;
+		}
+	}
+	return 0;
+}
+
+static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
+				    const siginfo_t __user *from)
+{
+	if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
+		return -EFAULT;
+	to->si_signo = signo;
+	return post_copy_siginfo_from_user(to, from);
+}
+
+int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
+{
+	if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
+		return -EFAULT;
+	return post_copy_siginfo_from_user(to, from);
+}
+
+#ifdef CONFIG_COMPAT
+/**
+ * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
+ * @to: compat siginfo destination
+ * @from: kernel siginfo source
+ *
+ * Note: This function does not work properly for the SIGCHLD on x32, but
+ * fortunately it doesn't have to.  The only valid callers for this function are
+ * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
+ * The latter does not care because SIGCHLD will never cause a coredump.
+ */
+void copy_siginfo_to_external32(struct compat_siginfo *to,
+		const struct kernel_siginfo *from)
+{
+	memset(to, 0, sizeof(*to));
+
+	to->si_signo = from->si_signo;
+	to->si_errno = from->si_errno;
+	to->si_code  = from->si_code;
+	switch(siginfo_layout(from->si_signo, from->si_code)) {
+	case SIL_KILL:
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
+		break;
+	case SIL_TIMER:
+		to->si_tid     = from->si_tid;
+		to->si_overrun = from->si_overrun;
+		to->si_int     = from->si_int;
+		break;
+	case SIL_POLL:
+		to->si_band = from->si_band;
+		to->si_fd   = from->si_fd;
+		break;
+	case SIL_FAULT:
+		to->si_addr = ptr_to_compat(from->si_addr);
+		break;
+	case SIL_FAULT_TRAPNO:
+		to->si_addr = ptr_to_compat(from->si_addr);
+		to->si_trapno = from->si_trapno;
+		break;
+	case SIL_FAULT_MCEERR:
+		to->si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr_lsb = from->si_addr_lsb;
+		break;
+	case SIL_FAULT_BNDERR:
+		to->si_addr = ptr_to_compat(from->si_addr);
+		to->si_lower = ptr_to_compat(from->si_lower);
+		to->si_upper = ptr_to_compat(from->si_upper);
+		break;
+	case SIL_FAULT_PKUERR:
+		to->si_addr = ptr_to_compat(from->si_addr);
+		to->si_pkey = from->si_pkey;
+		break;
+	case SIL_FAULT_PERF_EVENT:
+		to->si_addr = ptr_to_compat(from->si_addr);
+		to->si_perf_data = from->si_perf_data;
+		to->si_perf_type = from->si_perf_type;
+		to->si_perf_flags = from->si_perf_flags;
+		break;
+	case SIL_CHLD:
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
+		to->si_status = from->si_status;
+		to->si_utime = from->si_utime;
+		to->si_stime = from->si_stime;
+		break;
+	case SIL_RT:
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
+		to->si_int = from->si_int;
+		break;
+	case SIL_SYS:
+		to->si_call_addr = ptr_to_compat(from->si_call_addr);
+		to->si_syscall   = from->si_syscall;
+		to->si_arch      = from->si_arch;
+		break;
+	}
+}
+
+int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
+			   const struct kernel_siginfo *from)
+{
+	struct compat_siginfo new;
+
+	copy_siginfo_to_external32(&new, from);
+	if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
+		return -EFAULT;
+	return 0;
+}
+
+static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
+					 const struct compat_siginfo *from)
+{
+	clear_siginfo(to);
+	to->si_signo = from->si_signo;
+	to->si_errno = from->si_errno;
+	to->si_code  = from->si_code;
+	switch(siginfo_layout(from->si_signo, from->si_code)) {
+	case SIL_KILL:
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
+		break;
+	case SIL_TIMER:
+		to->si_tid     = from->si_tid;
+		to->si_overrun = from->si_overrun;
+		to->si_int     = from->si_int;
+		break;
+	case SIL_POLL:
+		to->si_band = from->si_band;
+		to->si_fd   = from->si_fd;
+		break;
+	case SIL_FAULT:
+		to->si_addr = compat_ptr(from->si_addr);
+		break;
+	case SIL_FAULT_TRAPNO:
+		to->si_addr = compat_ptr(from->si_addr);
+		to->si_trapno = from->si_trapno;
+		break;
+	case SIL_FAULT_MCEERR:
+		to->si_addr = compat_ptr(from->si_addr);
+		to->si_addr_lsb = from->si_addr_lsb;
+		break;
+	case SIL_FAULT_BNDERR:
+		to->si_addr = compat_ptr(from->si_addr);
+		to->si_lower = compat_ptr(from->si_lower);
+		to->si_upper = compat_ptr(from->si_upper);
+		break;
+	case SIL_FAULT_PKUERR:
+		to->si_addr = compat_ptr(from->si_addr);
+		to->si_pkey = from->si_pkey;
+		break;
+	case SIL_FAULT_PERF_EVENT:
+		to->si_addr = compat_ptr(from->si_addr);
+		to->si_perf_data = from->si_perf_data;
+		to->si_perf_type = from->si_perf_type;
+		to->si_perf_flags = from->si_perf_flags;
+		break;
+	case SIL_CHLD:
+		to->si_pid    = from->si_pid;
+		to->si_uid    = from->si_uid;
+		to->si_status = from->si_status;
+#ifdef CONFIG_X86_X32_ABI
+		if (in_x32_syscall()) {
+			to->si_utime = from->_sifields._sigchld_x32._utime;
+			to->si_stime = from->_sifields._sigchld_x32._stime;
+		} else
+#endif
+		{
+			to->si_utime = from->si_utime;
+			to->si_stime = from->si_stime;
+		}
+		break;
+	case SIL_RT:
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
+		to->si_int = from->si_int;
+		break;
+	case SIL_SYS:
+		to->si_call_addr = compat_ptr(from->si_call_addr);
+		to->si_syscall   = from->si_syscall;
+		to->si_arch      = from->si_arch;
+		break;
+	}
+	return 0;
+}
+
+static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
+				      const struct compat_siginfo __user *ufrom)
+{
+	struct compat_siginfo from;
+
+	if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
+		return -EFAULT;
+
+	from.si_signo = signo;
+	return post_copy_siginfo_from_user32(to, &from);
+}
+
+int copy_siginfo_from_user32(struct kernel_siginfo *to,
+			     const struct compat_siginfo __user *ufrom)
+{
+	struct compat_siginfo from;
+
+	if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
+		return -EFAULT;
+
+	return post_copy_siginfo_from_user32(to, &from);
+}
+#endif /* CONFIG_COMPAT */
+
+/**
+ *  do_sigtimedwait - wait for queued signals specified in @which
+ *  @which: queued signals to wait for
+ *  @info: if non-null, the signal's siginfo is returned here
+ *  @ts: upper bound on process time suspension
+ */
+static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
+		    const struct timespec64 *ts)
+{
+	ktime_t *to = NULL, timeout = KTIME_MAX;
+	struct task_struct *tsk = current;
+	sigset_t mask = *which;
+	enum pid_type type;
+	int sig, ret = 0;
+
+	if (ts) {
+		if (!timespec64_valid(ts))
+			return -EINVAL;
+		timeout = timespec64_to_ktime(*ts);
+		to = &timeout;
+	}
+
+	/*
+	 * Invert the set of allowed signals to get those we want to block.
+	 */
+	sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
+	signotset(&mask);
+
+	spin_lock_irq(&tsk->sighand->siglock);
+	sig = dequeue_signal(tsk, &mask, info, &type);
+	if (!sig && timeout) {
+		/*
+		 * None ready, temporarily unblock those we're interested
+		 * while we are sleeping in so that we'll be awakened when
+		 * they arrive. Unblocking is always fine, we can avoid
+		 * set_current_blocked().
+		 */
+		tsk->real_blocked = tsk->blocked;
+		sigandsets(&tsk->blocked, &tsk->blocked, &mask);
+		recalc_sigpending();
+		spin_unlock_irq(&tsk->sighand->siglock);
+
+		__set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
+		ret = schedule_hrtimeout_range(to, tsk->timer_slack_ns,
+					       HRTIMER_MODE_REL);
+		spin_lock_irq(&tsk->sighand->siglock);
+		__set_task_blocked(tsk, &tsk->real_blocked);
+		sigemptyset(&tsk->real_blocked);
+		sig = dequeue_signal(tsk, &mask, info, &type);
+	}
+	spin_unlock_irq(&tsk->sighand->siglock);
+
+	if (sig)
+		return sig;
+	return ret ? -EINTR : -EAGAIN;
+}
+
+/**
+ *  sys_rt_sigtimedwait - synchronously wait for queued signals specified
+ *			in @uthese
+ *  @uthese: queued signals to wait for
+ *  @uinfo: if non-null, the signal's siginfo is returned here
+ *  @uts: upper bound on process time suspension
+ *  @sigsetsize: size of sigset_t type
+ */
+SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
+		siginfo_t __user *, uinfo,
+		const struct __kernel_timespec __user *, uts,
+		size_t, sigsetsize)
+{
+	sigset_t these;
+	struct timespec64 ts;
+	kernel_siginfo_t info;
+	int ret;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	if (copy_from_user(&these, uthese, sizeof(these)))
+		return -EFAULT;
+
+	if (uts) {
+		if (get_timespec64(&ts, uts))
+			return -EFAULT;
+	}
+
+	ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
+
+	if (ret > 0 && uinfo) {
+		if (copy_siginfo_to_user(uinfo, &info))
+			ret = -EFAULT;
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
+		siginfo_t __user *, uinfo,
+		const struct old_timespec32 __user *, uts,
+		size_t, sigsetsize)
+{
+	sigset_t these;
+	struct timespec64 ts;
+	kernel_siginfo_t info;
+	int ret;
+
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	if (copy_from_user(&these, uthese, sizeof(these)))
+		return -EFAULT;
+
+	if (uts) {
+		if (get_old_timespec32(&ts, uts))
+			return -EFAULT;
+	}
+
+	ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
+
+	if (ret > 0 && uinfo) {
+		if (copy_siginfo_to_user(uinfo, &info))
+			ret = -EFAULT;
+	}
+
+	return ret;
+}
+#endif
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
+		struct compat_siginfo __user *, uinfo,
+		struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
+{
+	sigset_t s;
+	struct timespec64 t;
+	kernel_siginfo_t info;
+	long ret;
+
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	if (get_compat_sigset(&s, uthese))
+		return -EFAULT;
+
+	if (uts) {
+		if (get_timespec64(&t, uts))
+			return -EFAULT;
+	}
+
+	ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
+
+	if (ret > 0 && uinfo) {
+		if (copy_siginfo_to_user32(uinfo, &info))
+			ret = -EFAULT;
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
+		struct compat_siginfo __user *, uinfo,
+		struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
+{
+	sigset_t s;
+	struct timespec64 t;
+	kernel_siginfo_t info;
+	long ret;
+
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	if (get_compat_sigset(&s, uthese))
+		return -EFAULT;
+
+	if (uts) {
+		if (get_old_timespec32(&t, uts))
+			return -EFAULT;
+	}
+
+	ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
+
+	if (ret > 0 && uinfo) {
+		if (copy_siginfo_to_user32(uinfo, &info))
+			ret = -EFAULT;
+	}
+
+	return ret;
+}
+#endif
+#endif
+
+static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
+{
+	clear_siginfo(info);
+	info->si_signo = sig;
+	info->si_errno = 0;
+	info->si_code = SI_USER;
+	info->si_pid = task_tgid_vnr(current);
+	info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
+}
+
+/**
+ *  sys_kill - send a signal to a process
+ *  @pid: the PID of the process
+ *  @sig: signal to be sent
+ */
+SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
+{
+	struct kernel_siginfo info;
+
+	prepare_kill_siginfo(sig, &info);
+
+	return kill_something_info(sig, &info, pid);
+}
+
+/*
+ * Verify that the signaler and signalee either are in the same pid namespace
+ * or that the signaler's pid namespace is an ancestor of the signalee's pid
+ * namespace.
+ */
+static bool access_pidfd_pidns(struct pid *pid)
+{
+	struct pid_namespace *active = task_active_pid_ns(current);
+	struct pid_namespace *p = ns_of_pid(pid);
+
+	for (;;) {
+		if (!p)
+			return false;
+		if (p == active)
+			break;
+		p = p->parent;
+	}
+
+	return true;
+}
+
+static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo,
+		siginfo_t __user *info)
+{
+#ifdef CONFIG_COMPAT
+	/*
+	 * Avoid hooking up compat syscalls and instead handle necessary
+	 * conversions here. Note, this is a stop-gap measure and should not be
+	 * considered a generic solution.
+	 */
+	if (in_compat_syscall())
+		return copy_siginfo_from_user32(
+			kinfo, (struct compat_siginfo __user *)info);
+#endif
+	return copy_siginfo_from_user(kinfo, info);
+}
+
+static struct pid *pidfd_to_pid(const struct file *file)
+{
+	struct pid *pid;
+
+	pid = pidfd_pid(file);
+	if (!IS_ERR(pid))
+		return pid;
+
+	return tgid_pidfd_to_pid(file);
+}
+
+/**
+ * sys_pidfd_send_signal - Signal a process through a pidfd
+ * @pidfd:  file descriptor of the process
+ * @sig:    signal to send
+ * @info:   signal info
+ * @flags:  future flags
+ *
+ * The syscall currently only signals via PIDTYPE_PID which covers
+ * kill(<positive-pid>, <signal>. It does not signal threads or process
+ * groups.
+ * In order to extend the syscall to threads and process groups the @flags
+ * argument should be used. In essence, the @flags argument will determine
+ * what is signaled and not the file descriptor itself. Put in other words,
+ * grouping is a property of the flags argument not a property of the file
+ * descriptor.
+ *
+ * Return: 0 on success, negative errno on failure
+ */
+SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
+		siginfo_t __user *, info, unsigned int, flags)
+{
+	int ret;
+	struct fd f;
+	struct pid *pid;
+	kernel_siginfo_t kinfo;
+
+	/* Enforce flags be set to 0 until we add an extension. */
+	if (flags)
+		return -EINVAL;
+
+	f = fdget(pidfd);
+	if (!f.file)
+		return -EBADF;
+
+	/* Is this a pidfd? */
+	pid = pidfd_to_pid(f.file);
+	if (IS_ERR(pid)) {
+		ret = PTR_ERR(pid);
+		goto err;
+	}
+
+	ret = -EINVAL;
+	if (!access_pidfd_pidns(pid))
+		goto err;
+
+	if (info) {
+		ret = copy_siginfo_from_user_any(&kinfo, info);
+		if (unlikely(ret))
+			goto err;
+
+		ret = -EINVAL;
+		if (unlikely(sig != kinfo.si_signo))
+			goto err;
+
+		/* Only allow sending arbitrary signals to yourself. */
+		ret = -EPERM;
+		if ((task_pid(current) != pid) &&
+		    (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
+			goto err;
+	} else {
+		prepare_kill_siginfo(sig, &kinfo);
+	}
+
+	ret = kill_pid_info(sig, &kinfo, pid);
+
+err:
+	fdput(f);
+	return ret;
+}
+
+static int
+do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
+{
+	struct task_struct *p;
+	int error = -ESRCH;
+
+	rcu_read_lock();
+	p = find_task_by_vpid(pid);
+	if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
+		error = check_kill_permission(sig, info, p);
+		/*
+		 * The null signal is a permissions and process existence
+		 * probe.  No signal is actually delivered.
+		 */
+		if (!error && sig) {
+			error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
+			/*
+			 * If lock_task_sighand() failed we pretend the task
+			 * dies after receiving the signal. The window is tiny,
+			 * and the signal is private anyway.
+			 */
+			if (unlikely(error == -ESRCH))
+				error = 0;
+		}
+	}
+	rcu_read_unlock();
+
+	return error;
+}
+
+static int do_tkill(pid_t tgid, pid_t pid, int sig)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_code = SI_TKILL;
+	info.si_pid = task_tgid_vnr(current);
+	info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
+
+	return do_send_specific(tgid, pid, sig, &info);
+}
+
+/**
+ *  sys_tgkill - send signal to one specific thread
+ *  @tgid: the thread group ID of the thread
+ *  @pid: the PID of the thread
+ *  @sig: signal to be sent
+ *
+ *  This syscall also checks the @tgid and returns -ESRCH even if the PID
+ *  exists but it's not belonging to the target process anymore. This
+ *  method solves the problem of threads exiting and PIDs getting reused.
+ */
+SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
+{
+	/* This is only valid for single tasks */
+	if (pid <= 0 || tgid <= 0)
+		return -EINVAL;
+
+	return do_tkill(tgid, pid, sig);
+}
+
+/**
+ *  sys_tkill - send signal to one specific task
+ *  @pid: the PID of the task
+ *  @sig: signal to be sent
+ *
+ *  Send a signal to only one task, even if it's a CLONE_THREAD task.
+ */
+SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
+{
+	/* This is only valid for single tasks */
+	if (pid <= 0)
+		return -EINVAL;
+
+	return do_tkill(0, pid, sig);
+}
+
+static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
+{
+	/* Not even root can pretend to send signals from the kernel.
+	 * Nor can they impersonate a kill()/tgkill(), which adds source info.
+	 */
+	if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
+	    (task_pid_vnr(current) != pid))
+		return -EPERM;
+
+	/* POSIX.1b doesn't mention process groups.  */
+	return kill_proc_info(sig, info, pid);
+}
+
+/**
+ *  sys_rt_sigqueueinfo - send signal information to a signal
+ *  @pid: the PID of the thread
+ *  @sig: signal to be sent
+ *  @uinfo: signal info to be sent
+ */
+SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
+		siginfo_t __user *, uinfo)
+{
+	kernel_siginfo_t info;
+	int ret = __copy_siginfo_from_user(sig, &info, uinfo);
+	if (unlikely(ret))
+		return ret;
+	return do_rt_sigqueueinfo(pid, sig, &info);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
+			compat_pid_t, pid,
+			int, sig,
+			struct compat_siginfo __user *, uinfo)
+{
+	kernel_siginfo_t info;
+	int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
+	if (unlikely(ret))
+		return ret;
+	return do_rt_sigqueueinfo(pid, sig, &info);
+}
+#endif
+
+static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
+{
+	/* This is only valid for single tasks */
+	if (pid <= 0 || tgid <= 0)
+		return -EINVAL;
+
+	/* Not even root can pretend to send signals from the kernel.
+	 * Nor can they impersonate a kill()/tgkill(), which adds source info.
+	 */
+	if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
+	    (task_pid_vnr(current) != pid))
+		return -EPERM;
+
+	return do_send_specific(tgid, pid, sig, info);
+}
+
+SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
+		siginfo_t __user *, uinfo)
+{
+	kernel_siginfo_t info;
+	int ret = __copy_siginfo_from_user(sig, &info, uinfo);
+	if (unlikely(ret))
+		return ret;
+	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
+			compat_pid_t, tgid,
+			compat_pid_t, pid,
+			int, sig,
+			struct compat_siginfo __user *, uinfo)
+{
+	kernel_siginfo_t info;
+	int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
+	if (unlikely(ret))
+		return ret;
+	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
+}
+#endif
+
+/*
+ * For kthreads only, must not be used if cloned with CLONE_SIGHAND
+ */
+void kernel_sigaction(int sig, __sighandler_t action)
+{
+	spin_lock_irq(&current->sighand->siglock);
+	current->sighand->action[sig - 1].sa.sa_handler = action;
+	if (action == SIG_IGN) {
+		sigset_t mask;
+
+		sigemptyset(&mask);
+		sigaddset(&mask, sig);
+
+		flush_sigqueue_mask(&mask, &current->signal->shared_pending);
+		flush_sigqueue_mask(&mask, &current->pending);
+		recalc_sigpending();
+	}
+	spin_unlock_irq(&current->sighand->siglock);
+}
+EXPORT_SYMBOL(kernel_sigaction);
+
+void __weak sigaction_compat_abi(struct k_sigaction *act,
+		struct k_sigaction *oact)
+{
+}
+
+int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
+{
+	struct task_struct *p = current, *t;
+	struct k_sigaction *k;
+	sigset_t mask;
+
+	if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
+		return -EINVAL;
+
+	k = &p->sighand->action[sig-1];
+
+	spin_lock_irq(&p->sighand->siglock);
+	if (k->sa.sa_flags & SA_IMMUTABLE) {
+		spin_unlock_irq(&p->sighand->siglock);
+		return -EINVAL;
+	}
+	if (oact)
+		*oact = *k;
+
+	/*
+	 * Make sure that we never accidentally claim to support SA_UNSUPPORTED,
+	 * e.g. by having an architecture use the bit in their uapi.
+	 */
+	BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED);
+
+	/*
+	 * Clear unknown flag bits in order to allow userspace to detect missing
+	 * support for flag bits and to allow the kernel to use non-uapi bits
+	 * internally.
+	 */
+	if (act)
+		act->sa.sa_flags &= UAPI_SA_FLAGS;
+	if (oact)
+		oact->sa.sa_flags &= UAPI_SA_FLAGS;
+
+	sigaction_compat_abi(act, oact);
+
+	if (act) {
+		sigdelsetmask(&act->sa.sa_mask,
+			      sigmask(SIGKILL) | sigmask(SIGSTOP));
+		*k = *act;
+		/*
+		 * POSIX 3.3.1.3:
+		 *  "Setting a signal action to SIG_IGN for a signal that is
+		 *   pending shall cause the pending signal to be discarded,
+		 *   whether or not it is blocked."
+		 *
+		 *  "Setting a signal action to SIG_DFL for a signal that is
+		 *   pending and whose default action is to ignore the signal
+		 *   (for example, SIGCHLD), shall cause the pending signal to
+		 *   be discarded, whether or not it is blocked"
+		 */
+		if (sig_handler_ignored(sig_handler(p, sig), sig)) {
+			sigemptyset(&mask);
+			sigaddset(&mask, sig);
+			flush_sigqueue_mask(&mask, &p->signal->shared_pending);
+			for_each_thread(p, t)
+				flush_sigqueue_mask(&mask, &t->pending);
+		}
+	}
+
+	spin_unlock_irq(&p->sighand->siglock);
+	return 0;
+}
+
+#ifdef CONFIG_DYNAMIC_SIGFRAME
+static inline void sigaltstack_lock(void)
+	__acquires(&current->sighand->siglock)
+{
+	spin_lock_irq(&current->sighand->siglock);
+}
+
+static inline void sigaltstack_unlock(void)
+	__releases(&current->sighand->siglock)
+{
+	spin_unlock_irq(&current->sighand->siglock);
+}
+#else
+static inline void sigaltstack_lock(void) { }
+static inline void sigaltstack_unlock(void) { }
+#endif
+
+static int
+do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
+		size_t min_ss_size)
+{
+	struct task_struct *t = current;
+	int ret = 0;
+
+	if (oss) {
+		memset(oss, 0, sizeof(stack_t));
+		oss->ss_sp = (void __user *) t->sas_ss_sp;
+		oss->ss_size = t->sas_ss_size;
+		oss->ss_flags = sas_ss_flags(sp) |
+			(current->sas_ss_flags & SS_FLAG_BITS);
+	}
+
+	if (ss) {
+		void __user *ss_sp = ss->ss_sp;
+		size_t ss_size = ss->ss_size;
+		unsigned ss_flags = ss->ss_flags;
+		int ss_mode;
+
+		if (unlikely(on_sig_stack(sp)))
+			return -EPERM;
+
+		ss_mode = ss_flags & ~SS_FLAG_BITS;
+		if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
+				ss_mode != 0))
+			return -EINVAL;
+
+		/*
+		 * Return before taking any locks if no actual
+		 * sigaltstack changes were requested.
+		 */
+		if (t->sas_ss_sp == (unsigned long)ss_sp &&
+		    t->sas_ss_size == ss_size &&
+		    t->sas_ss_flags == ss_flags)
+			return 0;
+
+		sigaltstack_lock();
+		if (ss_mode == SS_DISABLE) {
+			ss_size = 0;
+			ss_sp = NULL;
+		} else {
+			if (unlikely(ss_size < min_ss_size))
+				ret = -ENOMEM;
+			if (!sigaltstack_size_valid(ss_size))
+				ret = -ENOMEM;
+		}
+		if (!ret) {
+			t->sas_ss_sp = (unsigned long) ss_sp;
+			t->sas_ss_size = ss_size;
+			t->sas_ss_flags = ss_flags;
+		}
+		sigaltstack_unlock();
+	}
+	return ret;
+}
+
+SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
+{
+	stack_t new, old;
+	int err;
+	if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
+		return -EFAULT;
+	err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
+			      current_user_stack_pointer(),
+			      MINSIGSTKSZ);
+	if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
+		err = -EFAULT;
+	return err;
+}
+
+int restore_altstack(const stack_t __user *uss)
+{
+	stack_t new;
+	if (copy_from_user(&new, uss, sizeof(stack_t)))
+		return -EFAULT;
+	(void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
+			     MINSIGSTKSZ);
+	/* squash all but EFAULT for now */
+	return 0;
+}
+
+int __save_altstack(stack_t __user *uss, unsigned long sp)
+{
+	struct task_struct *t = current;
+	int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
+		__put_user(t->sas_ss_flags, &uss->ss_flags) |
+		__put_user(t->sas_ss_size, &uss->ss_size);
+	return err;
+}
+
+#ifdef CONFIG_COMPAT
+static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
+				 compat_stack_t __user *uoss_ptr)
+{
+	stack_t uss, uoss;
+	int ret;
+
+	if (uss_ptr) {
+		compat_stack_t uss32;
+		if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
+			return -EFAULT;
+		uss.ss_sp = compat_ptr(uss32.ss_sp);
+		uss.ss_flags = uss32.ss_flags;
+		uss.ss_size = uss32.ss_size;
+	}
+	ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
+			     compat_user_stack_pointer(),
+			     COMPAT_MINSIGSTKSZ);
+	if (ret >= 0 && uoss_ptr)  {
+		compat_stack_t old;
+		memset(&old, 0, sizeof(old));
+		old.ss_sp = ptr_to_compat(uoss.ss_sp);
+		old.ss_flags = uoss.ss_flags;
+		old.ss_size = uoss.ss_size;
+		if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
+			ret = -EFAULT;
+	}
+	return ret;
+}
+
+COMPAT_SYSCALL_DEFINE2(sigaltstack,
+			const compat_stack_t __user *, uss_ptr,
+			compat_stack_t __user *, uoss_ptr)
+{
+	return do_compat_sigaltstack(uss_ptr, uoss_ptr);
+}
+
+int compat_restore_altstack(const compat_stack_t __user *uss)
+{
+	int err = do_compat_sigaltstack(uss, NULL);
+	/* squash all but -EFAULT for now */
+	return err == -EFAULT ? err : 0;
+}
+
+int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
+{
+	int err;
+	struct task_struct *t = current;
+	err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
+			 &uss->ss_sp) |
+		__put_user(t->sas_ss_flags, &uss->ss_flags) |
+		__put_user(t->sas_ss_size, &uss->ss_size);
+	return err;
+}
+#endif
+
+#ifdef __ARCH_WANT_SYS_SIGPENDING
+
+/**
+ *  sys_sigpending - examine pending signals
+ *  @uset: where mask of pending signal is returned
+ */
+SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
+{
+	sigset_t set;
+
+	if (sizeof(old_sigset_t) > sizeof(*uset))
+		return -EINVAL;
+
+	do_sigpending(&set);
+
+	if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
+		return -EFAULT;
+
+	return 0;
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
+{
+	sigset_t set;
+
+	do_sigpending(&set);
+
+	return put_user(set.sig[0], set32);
+}
+#endif
+
+#endif
+
+#ifdef __ARCH_WANT_SYS_SIGPROCMASK
+/**
+ *  sys_sigprocmask - examine and change blocked signals
+ *  @how: whether to add, remove, or set signals
+ *  @nset: signals to add or remove (if non-null)
+ *  @oset: previous value of signal mask if non-null
+ *
+ * Some platforms have their own version with special arguments;
+ * others support only sys_rt_sigprocmask.
+ */
+
+SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
+		old_sigset_t __user *, oset)
+{
+	old_sigset_t old_set, new_set;
+	sigset_t new_blocked;
+
+	old_set = current->blocked.sig[0];
+
+	if (nset) {
+		if (copy_from_user(&new_set, nset, sizeof(*nset)))
+			return -EFAULT;
+
+		new_blocked = current->blocked;
+
+		switch (how) {
+		case SIG_BLOCK:
+			sigaddsetmask(&new_blocked, new_set);
+			break;
+		case SIG_UNBLOCK:
+			sigdelsetmask(&new_blocked, new_set);
+			break;
+		case SIG_SETMASK:
+			new_blocked.sig[0] = new_set;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		set_current_blocked(&new_blocked);
+	}
+
+	if (oset) {
+		if (copy_to_user(oset, &old_set, sizeof(*oset)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+#endif /* __ARCH_WANT_SYS_SIGPROCMASK */
+
+#ifndef CONFIG_ODD_RT_SIGACTION
+/**
+ *  sys_rt_sigaction - alter an action taken by a process
+ *  @sig: signal to be sent
+ *  @act: new sigaction
+ *  @oact: used to save the previous sigaction
+ *  @sigsetsize: size of sigset_t type
+ */
+SYSCALL_DEFINE4(rt_sigaction, int, sig,
+		const struct sigaction __user *, act,
+		struct sigaction __user *, oact,
+		size_t, sigsetsize)
+{
+	struct k_sigaction new_sa, old_sa;
+	int ret;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
+		return -EFAULT;
+
+	ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
+	if (ret)
+		return ret;
+
+	if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
+		return -EFAULT;
+
+	return 0;
+}
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
+		const struct compat_sigaction __user *, act,
+		struct compat_sigaction __user *, oact,
+		compat_size_t, sigsetsize)
+{
+	struct k_sigaction new_ka, old_ka;
+#ifdef __ARCH_HAS_SA_RESTORER
+	compat_uptr_t restorer;
+#endif
+	int ret;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(compat_sigset_t))
+		return -EINVAL;
+
+	if (act) {
+		compat_uptr_t handler;
+		ret = get_user(handler, &act->sa_handler);
+		new_ka.sa.sa_handler = compat_ptr(handler);
+#ifdef __ARCH_HAS_SA_RESTORER
+		ret |= get_user(restorer, &act->sa_restorer);
+		new_ka.sa.sa_restorer = compat_ptr(restorer);
+#endif
+		ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
+		ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
+		if (ret)
+			return -EFAULT;
+	}
+
+	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
+	if (!ret && oact) {
+		ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), 
+			       &oact->sa_handler);
+		ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
+					 sizeof(oact->sa_mask));
+		ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
+#ifdef __ARCH_HAS_SA_RESTORER
+		ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
+				&oact->sa_restorer);
+#endif
+	}
+	return ret;
+}
+#endif
+#endif /* !CONFIG_ODD_RT_SIGACTION */
+
+#ifdef CONFIG_OLD_SIGACTION
+SYSCALL_DEFINE3(sigaction, int, sig,
+		const struct old_sigaction __user *, act,
+	        struct old_sigaction __user *, oact)
+{
+	struct k_sigaction new_ka, old_ka;
+	int ret;
+
+	if (act) {
+		old_sigset_t mask;
+		if (!access_ok(act, sizeof(*act)) ||
+		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
+		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
+		    __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
+		    __get_user(mask, &act->sa_mask))
+			return -EFAULT;
+#ifdef __ARCH_HAS_KA_RESTORER
+		new_ka.ka_restorer = NULL;
+#endif
+		siginitset(&new_ka.sa.sa_mask, mask);
+	}
+
+	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
+
+	if (!ret && oact) {
+		if (!access_ok(oact, sizeof(*oact)) ||
+		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
+		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
+		    __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
+		    __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
+			return -EFAULT;
+	}
+
+	return ret;
+}
+#endif
+#ifdef CONFIG_COMPAT_OLD_SIGACTION
+COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
+		const struct compat_old_sigaction __user *, act,
+	        struct compat_old_sigaction __user *, oact)
+{
+	struct k_sigaction new_ka, old_ka;
+	int ret;
+	compat_old_sigset_t mask;
+	compat_uptr_t handler, restorer;
+
+	if (act) {
+		if (!access_ok(act, sizeof(*act)) ||
+		    __get_user(handler, &act->sa_handler) ||
+		    __get_user(restorer, &act->sa_restorer) ||
+		    __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
+		    __get_user(mask, &act->sa_mask))
+			return -EFAULT;
+
+#ifdef __ARCH_HAS_KA_RESTORER
+		new_ka.ka_restorer = NULL;
+#endif
+		new_ka.sa.sa_handler = compat_ptr(handler);
+		new_ka.sa.sa_restorer = compat_ptr(restorer);
+		siginitset(&new_ka.sa.sa_mask, mask);
+	}
+
+	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
+
+	if (!ret && oact) {
+		if (!access_ok(oact, sizeof(*oact)) ||
+		    __put_user(ptr_to_compat(old_ka.sa.sa_handler),
+			       &oact->sa_handler) ||
+		    __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
+			       &oact->sa_restorer) ||
+		    __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
+		    __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
+			return -EFAULT;
+	}
+	return ret;
+}
+#endif
+
+#ifdef CONFIG_SGETMASK_SYSCALL
+
+/*
+ * For backwards compatibility.  Functionality superseded by sigprocmask.
+ */
+SYSCALL_DEFINE0(sgetmask)
+{
+	/* SMP safe */
+	return current->blocked.sig[0];
+}
+
+SYSCALL_DEFINE1(ssetmask, int, newmask)
+{
+	int old = current->blocked.sig[0];
+	sigset_t newset;
+
+	siginitset(&newset, newmask);
+	set_current_blocked(&newset);
+
+	return old;
+}
+#endif /* CONFIG_SGETMASK_SYSCALL */
+
+#ifdef __ARCH_WANT_SYS_SIGNAL
+/*
+ * For backwards compatibility.  Functionality superseded by sigaction.
+ */
+SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
+{
+	struct k_sigaction new_sa, old_sa;
+	int ret;
+
+	new_sa.sa.sa_handler = handler;
+	new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
+	sigemptyset(&new_sa.sa.sa_mask);
+
+	ret = do_sigaction(sig, &new_sa, &old_sa);
+
+	return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
+}
+#endif /* __ARCH_WANT_SYS_SIGNAL */
+
+#ifdef __ARCH_WANT_SYS_PAUSE
+
+SYSCALL_DEFINE0(pause)
+{
+	while (!signal_pending(current)) {
+		__set_current_state(TASK_INTERRUPTIBLE);
+		schedule();
+	}
+	return -ERESTARTNOHAND;
+}
+
+#endif
+
+static int sigsuspend(sigset_t *set)
+{
+	current->saved_sigmask = current->blocked;
+	set_current_blocked(set);
+
+	while (!signal_pending(current)) {
+		__set_current_state(TASK_INTERRUPTIBLE);
+		schedule();
+	}
+	set_restore_sigmask();
+	return -ERESTARTNOHAND;
+}
+
+/**
+ *  sys_rt_sigsuspend - replace the signal mask for a value with the
+ *	@unewset value until a signal is received
+ *  @unewset: new signal mask value
+ *  @sigsetsize: size of sigset_t type
+ */
+SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
+{
+	sigset_t newset;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	if (copy_from_user(&newset, unewset, sizeof(newset)))
+		return -EFAULT;
+	return sigsuspend(&newset);
+}
+ 
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
+{
+	sigset_t newset;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	if (get_compat_sigset(&newset, unewset))
+		return -EFAULT;
+	return sigsuspend(&newset);
+}
+#endif
+
+#ifdef CONFIG_OLD_SIGSUSPEND
+SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
+{
+	sigset_t blocked;
+	siginitset(&blocked, mask);
+	return sigsuspend(&blocked);
+}
+#endif
+#ifdef CONFIG_OLD_SIGSUSPEND3
+SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
+{
+	sigset_t blocked;
+	siginitset(&blocked, mask);
+	return sigsuspend(&blocked);
+}
+#endif
+
+__weak const char *arch_vma_name(struct vm_area_struct *vma)
+{
+	return NULL;
+}
+
+static inline void siginfo_buildtime_checks(void)
+{
+	BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
+
+	/* Verify the offsets in the two siginfos match */
+#define CHECK_OFFSET(field) \
+	BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
+
+	/* kill */
+	CHECK_OFFSET(si_pid);
+	CHECK_OFFSET(si_uid);
+
+	/* timer */
+	CHECK_OFFSET(si_tid);
+	CHECK_OFFSET(si_overrun);
+	CHECK_OFFSET(si_value);
+
+	/* rt */
+	CHECK_OFFSET(si_pid);
+	CHECK_OFFSET(si_uid);
+	CHECK_OFFSET(si_value);
+
+	/* sigchld */
+	CHECK_OFFSET(si_pid);
+	CHECK_OFFSET(si_uid);
+	CHECK_OFFSET(si_status);
+	CHECK_OFFSET(si_utime);
+	CHECK_OFFSET(si_stime);
+
+	/* sigfault */
+	CHECK_OFFSET(si_addr);
+	CHECK_OFFSET(si_trapno);
+	CHECK_OFFSET(si_addr_lsb);
+	CHECK_OFFSET(si_lower);
+	CHECK_OFFSET(si_upper);
+	CHECK_OFFSET(si_pkey);
+	CHECK_OFFSET(si_perf_data);
+	CHECK_OFFSET(si_perf_type);
+	CHECK_OFFSET(si_perf_flags);
+
+	/* sigpoll */
+	CHECK_OFFSET(si_band);
+	CHECK_OFFSET(si_fd);
+
+	/* sigsys */
+	CHECK_OFFSET(si_call_addr);
+	CHECK_OFFSET(si_syscall);
+	CHECK_OFFSET(si_arch);
+#undef CHECK_OFFSET
+
+	/* usb asyncio */
+	BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
+		     offsetof(struct siginfo, si_addr));
+	if (sizeof(int) == sizeof(void __user *)) {
+		BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
+			     sizeof(void __user *));
+	} else {
+		BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
+			      sizeof_field(struct siginfo, si_uid)) !=
+			     sizeof(void __user *));
+		BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
+			     offsetof(struct siginfo, si_uid));
+	}
+#ifdef CONFIG_COMPAT
+	BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
+		     offsetof(struct compat_siginfo, si_addr));
+	BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
+		     sizeof(compat_uptr_t));
+	BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
+		     sizeof_field(struct siginfo, si_pid));
+#endif
+}
+
+void __init signals_init(void)
+{
+	siginfo_buildtime_checks();
+
+	sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC | SLAB_ACCOUNT);
+}
+
+#ifdef CONFIG_KGDB_KDB
+#include <linux/kdb.h>
+/*
+ * kdb_send_sig - Allows kdb to send signals without exposing
+ * signal internals.  This function checks if the required locks are
+ * available before calling the main signal code, to avoid kdb
+ * deadlocks.
+ */
+void kdb_send_sig(struct task_struct *t, int sig)
+{
+	static struct task_struct *kdb_prev_t;
+	int new_t, ret;
+	if (!spin_trylock(&t->sighand->siglock)) {
+		kdb_printf("Can't do kill command now.\n"
+			   "The sigmask lock is held somewhere else in "
+			   "kernel, try again later\n");
+		return;
+	}
+	new_t = kdb_prev_t != t;
+	kdb_prev_t = t;
+	if (!task_is_running(t) && new_t) {
+		spin_unlock(&t->sighand->siglock);
+		kdb_printf("Process is not RUNNING, sending a signal from "
+			   "kdb risks deadlock\n"
+			   "on the run queue locks. "
+			   "The signal has _not_ been sent.\n"
+			   "Reissue the kill command if you want to risk "
+			   "the deadlock.\n");
+		return;
+	}
+	ret = send_signal_locked(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
+	spin_unlock(&t->sighand->siglock);
+	if (ret)
+		kdb_printf("Fail to deliver Signal %d to process %d.\n",
+			   sig, t->pid);
+	else
+		kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
+}
+#endif	/* CONFIG_KGDB_KDB */
diff --git a/kernel/smp.c b/kernel/smp.c
new file mode 100644
index 000000000..63e466bb6
--- /dev/null
+++ b/kernel/smp.c
@@ -0,0 +1,1268 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic helpers for smp ipi calls
+ *
+ * (C) Jens Axboe <jens.axboe@oracle.com> 2008
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/irq_work.h>
+#include <linux/rcupdate.h>
+#include <linux/rculist.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/gfp.h>
+#include <linux/smp.h>
+#include <linux/cpu.h>
+#include <linux/sched.h>
+#include <linux/sched/idle.h>
+#include <linux/hypervisor.h>
+#include <linux/sched/clock.h>
+#include <linux/nmi.h>
+#include <linux/sched/debug.h>
+#include <linux/jump_label.h>
+
+#include "smpboot.h"
+#include "sched/smp.h"
+
+#define CSD_TYPE(_csd)	((_csd)->node.u_flags & CSD_FLAG_TYPE_MASK)
+
+#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+union cfd_seq_cnt {
+	u64		val;
+	struct {
+		u64	src:16;
+		u64	dst:16;
+#define CFD_SEQ_NOCPU	0xffff
+		u64	type:4;
+#define CFD_SEQ_QUEUE	0
+#define CFD_SEQ_IPI	1
+#define CFD_SEQ_NOIPI	2
+#define CFD_SEQ_PING	3
+#define CFD_SEQ_PINGED	4
+#define CFD_SEQ_HANDLE	5
+#define CFD_SEQ_DEQUEUE	6
+#define CFD_SEQ_IDLE	7
+#define CFD_SEQ_GOTIPI	8
+#define CFD_SEQ_HDLEND	9
+		u64	cnt:28;
+	}		u;
+};
+
+static char *seq_type[] = {
+	[CFD_SEQ_QUEUE]		= "queue",
+	[CFD_SEQ_IPI]		= "ipi",
+	[CFD_SEQ_NOIPI]		= "noipi",
+	[CFD_SEQ_PING]		= "ping",
+	[CFD_SEQ_PINGED]	= "pinged",
+	[CFD_SEQ_HANDLE]	= "handle",
+	[CFD_SEQ_DEQUEUE]	= "dequeue (src CPU 0 == empty)",
+	[CFD_SEQ_IDLE]		= "idle",
+	[CFD_SEQ_GOTIPI]	= "gotipi",
+	[CFD_SEQ_HDLEND]	= "hdlend (src CPU 0 == early)",
+};
+
+struct cfd_seq_local {
+	u64	ping;
+	u64	pinged;
+	u64	handle;
+	u64	dequeue;
+	u64	idle;
+	u64	gotipi;
+	u64	hdlend;
+};
+#endif
+
+struct cfd_percpu {
+	call_single_data_t	csd;
+#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+	u64	seq_queue;
+	u64	seq_ipi;
+	u64	seq_noipi;
+#endif
+};
+
+struct call_function_data {
+	struct cfd_percpu	__percpu *pcpu;
+	cpumask_var_t		cpumask;
+	cpumask_var_t		cpumask_ipi;
+};
+
+static DEFINE_PER_CPU_ALIGNED(struct call_function_data, cfd_data);
+
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue);
+
+static void __flush_smp_call_function_queue(bool warn_cpu_offline);
+
+int smpcfd_prepare_cpu(unsigned int cpu)
+{
+	struct call_function_data *cfd = &per_cpu(cfd_data, cpu);
+
+	if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL,
+				     cpu_to_node(cpu)))
+		return -ENOMEM;
+	if (!zalloc_cpumask_var_node(&cfd->cpumask_ipi, GFP_KERNEL,
+				     cpu_to_node(cpu))) {
+		free_cpumask_var(cfd->cpumask);
+		return -ENOMEM;
+	}
+	cfd->pcpu = alloc_percpu(struct cfd_percpu);
+	if (!cfd->pcpu) {
+		free_cpumask_var(cfd->cpumask);
+		free_cpumask_var(cfd->cpumask_ipi);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+int smpcfd_dead_cpu(unsigned int cpu)
+{
+	struct call_function_data *cfd = &per_cpu(cfd_data, cpu);
+
+	free_cpumask_var(cfd->cpumask);
+	free_cpumask_var(cfd->cpumask_ipi);
+	free_percpu(cfd->pcpu);
+	return 0;
+}
+
+int smpcfd_dying_cpu(unsigned int cpu)
+{
+	/*
+	 * The IPIs for the smp-call-function callbacks queued by other
+	 * CPUs might arrive late, either due to hardware latencies or
+	 * because this CPU disabled interrupts (inside stop-machine)
+	 * before the IPIs were sent. So flush out any pending callbacks
+	 * explicitly (without waiting for the IPIs to arrive), to
+	 * ensure that the outgoing CPU doesn't go offline with work
+	 * still pending.
+	 */
+	__flush_smp_call_function_queue(false);
+	irq_work_run();
+	return 0;
+}
+
+void __init call_function_init(void)
+{
+	int i;
+
+	for_each_possible_cpu(i)
+		init_llist_head(&per_cpu(call_single_queue, i));
+
+	smpcfd_prepare_cpu(smp_processor_id());
+}
+
+#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+
+static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
+static DEFINE_STATIC_KEY_FALSE(csdlock_debug_extended);
+
+static int __init csdlock_debug(char *str)
+{
+	unsigned int val = 0;
+
+	if (str && !strcmp(str, "ext")) {
+		val = 1;
+		static_branch_enable(&csdlock_debug_extended);
+	} else
+		get_option(&str, &val);
+
+	if (val)
+		static_branch_enable(&csdlock_debug_enabled);
+
+	return 1;
+}
+__setup("csdlock_debug=", csdlock_debug);
+
+static DEFINE_PER_CPU(call_single_data_t *, cur_csd);
+static DEFINE_PER_CPU(smp_call_func_t, cur_csd_func);
+static DEFINE_PER_CPU(void *, cur_csd_info);
+static DEFINE_PER_CPU(struct cfd_seq_local, cfd_seq_local);
+
+static ulong csd_lock_timeout = 5000;  /* CSD lock timeout in milliseconds. */
+module_param(csd_lock_timeout, ulong, 0444);
+static int panic_on_ipistall;  /* CSD panic timeout in milliseconds, 300000 for five minutes. */
+module_param(panic_on_ipistall, int, 0444);
+
+static atomic_t csd_bug_count = ATOMIC_INIT(0);
+static u64 cfd_seq;
+
+#define CFD_SEQ(s, d, t, c)	\
+	(union cfd_seq_cnt){ .u.src = s, .u.dst = d, .u.type = t, .u.cnt = c }
+
+static u64 cfd_seq_inc(unsigned int src, unsigned int dst, unsigned int type)
+{
+	union cfd_seq_cnt new, old;
+
+	new = CFD_SEQ(src, dst, type, 0);
+
+	do {
+		old.val = READ_ONCE(cfd_seq);
+		new.u.cnt = old.u.cnt + 1;
+	} while (cmpxchg(&cfd_seq, old.val, new.val) != old.val);
+
+	return old.val;
+}
+
+#define cfd_seq_store(var, src, dst, type)				\
+	do {								\
+		if (static_branch_unlikely(&csdlock_debug_extended))	\
+			var = cfd_seq_inc(src, dst, type);		\
+	} while (0)
+
+/* Record current CSD work for current CPU, NULL to erase. */
+static void __csd_lock_record(struct __call_single_data *csd)
+{
+	if (!csd) {
+		smp_mb(); /* NULL cur_csd after unlock. */
+		__this_cpu_write(cur_csd, NULL);
+		return;
+	}
+	__this_cpu_write(cur_csd_func, csd->func);
+	__this_cpu_write(cur_csd_info, csd->info);
+	smp_wmb(); /* func and info before csd. */
+	__this_cpu_write(cur_csd, csd);
+	smp_mb(); /* Update cur_csd before function call. */
+		  /* Or before unlock, as the case may be. */
+}
+
+static __always_inline void csd_lock_record(struct __call_single_data *csd)
+{
+	if (static_branch_unlikely(&csdlock_debug_enabled))
+		__csd_lock_record(csd);
+}
+
+static int csd_lock_wait_getcpu(struct __call_single_data *csd)
+{
+	unsigned int csd_type;
+
+	csd_type = CSD_TYPE(csd);
+	if (csd_type == CSD_TYPE_ASYNC || csd_type == CSD_TYPE_SYNC)
+		return csd->node.dst; /* Other CSD_TYPE_ values might not have ->dst. */
+	return -1;
+}
+
+static void cfd_seq_data_add(u64 val, unsigned int src, unsigned int dst,
+			     unsigned int type, union cfd_seq_cnt *data,
+			     unsigned int *n_data, unsigned int now)
+{
+	union cfd_seq_cnt new[2];
+	unsigned int i, j, k;
+
+	new[0].val = val;
+	new[1] = CFD_SEQ(src, dst, type, new[0].u.cnt + 1);
+
+	for (i = 0; i < 2; i++) {
+		if (new[i].u.cnt <= now)
+			new[i].u.cnt |= 0x80000000U;
+		for (j = 0; j < *n_data; j++) {
+			if (new[i].u.cnt == data[j].u.cnt) {
+				/* Direct read value trumps generated one. */
+				if (i == 0)
+					data[j].val = new[i].val;
+				break;
+			}
+			if (new[i].u.cnt < data[j].u.cnt) {
+				for (k = *n_data; k > j; k--)
+					data[k].val = data[k - 1].val;
+				data[j].val = new[i].val;
+				(*n_data)++;
+				break;
+			}
+		}
+		if (j == *n_data) {
+			data[j].val = new[i].val;
+			(*n_data)++;
+		}
+	}
+}
+
+static const char *csd_lock_get_type(unsigned int type)
+{
+	return (type >= ARRAY_SIZE(seq_type)) ? "?" : seq_type[type];
+}
+
+static void csd_lock_print_extended(struct __call_single_data *csd, int cpu)
+{
+	struct cfd_seq_local *seq = &per_cpu(cfd_seq_local, cpu);
+	unsigned int srccpu = csd->node.src;
+	struct call_function_data *cfd = per_cpu_ptr(&cfd_data, srccpu);
+	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+	unsigned int now;
+	union cfd_seq_cnt data[2 * ARRAY_SIZE(seq_type)];
+	unsigned int n_data = 0, i;
+
+	data[0].val = READ_ONCE(cfd_seq);
+	now = data[0].u.cnt;
+
+	cfd_seq_data_add(pcpu->seq_queue,			srccpu, cpu,	       CFD_SEQ_QUEUE,  data, &n_data, now);
+	cfd_seq_data_add(pcpu->seq_ipi,				srccpu, cpu,	       CFD_SEQ_IPI,    data, &n_data, now);
+	cfd_seq_data_add(pcpu->seq_noipi,			srccpu, cpu,	       CFD_SEQ_NOIPI,  data, &n_data, now);
+
+	cfd_seq_data_add(per_cpu(cfd_seq_local.ping, srccpu),	srccpu, CFD_SEQ_NOCPU, CFD_SEQ_PING,   data, &n_data, now);
+	cfd_seq_data_add(per_cpu(cfd_seq_local.pinged, srccpu), srccpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED, data, &n_data, now);
+
+	cfd_seq_data_add(seq->idle,    CFD_SEQ_NOCPU, cpu, CFD_SEQ_IDLE,    data, &n_data, now);
+	cfd_seq_data_add(seq->gotipi,  CFD_SEQ_NOCPU, cpu, CFD_SEQ_GOTIPI,  data, &n_data, now);
+	cfd_seq_data_add(seq->handle,  CFD_SEQ_NOCPU, cpu, CFD_SEQ_HANDLE,  data, &n_data, now);
+	cfd_seq_data_add(seq->dequeue, CFD_SEQ_NOCPU, cpu, CFD_SEQ_DEQUEUE, data, &n_data, now);
+	cfd_seq_data_add(seq->hdlend,  CFD_SEQ_NOCPU, cpu, CFD_SEQ_HDLEND,  data, &n_data, now);
+
+	for (i = 0; i < n_data; i++) {
+		pr_alert("\tcsd: cnt(%07x): %04x->%04x %s\n",
+			 data[i].u.cnt & ~0x80000000U, data[i].u.src,
+			 data[i].u.dst, csd_lock_get_type(data[i].u.type));
+	}
+	pr_alert("\tcsd: cnt now: %07x\n", now);
+}
+
+/*
+ * Complain if too much time spent waiting.  Note that only
+ * the CSD_TYPE_SYNC/ASYNC types provide the destination CPU,
+ * so waiting on other types gets much less information.
+ */
+static bool csd_lock_wait_toolong(struct __call_single_data *csd, u64 ts0, u64 *ts1, int *bug_id)
+{
+	int cpu = -1;
+	int cpux;
+	bool firsttime;
+	u64 ts2, ts_delta;
+	call_single_data_t *cpu_cur_csd;
+	unsigned int flags = READ_ONCE(csd->node.u_flags);
+	unsigned long long csd_lock_timeout_ns = csd_lock_timeout * NSEC_PER_MSEC;
+
+	if (!(flags & CSD_FLAG_LOCK)) {
+		if (!unlikely(*bug_id))
+			return true;
+		cpu = csd_lock_wait_getcpu(csd);
+		pr_alert("csd: CSD lock (#%d) got unstuck on CPU#%02d, CPU#%02d released the lock.\n",
+			 *bug_id, raw_smp_processor_id(), cpu);
+		return true;
+	}
+
+	ts2 = sched_clock();
+	/* How long since we last checked for a stuck CSD lock.*/
+	ts_delta = ts2 - *ts1;
+	if (likely(ts_delta <= csd_lock_timeout_ns || csd_lock_timeout_ns == 0))
+		return false;
+
+	firsttime = !*bug_id;
+	if (firsttime)
+		*bug_id = atomic_inc_return(&csd_bug_count);
+	cpu = csd_lock_wait_getcpu(csd);
+	if (WARN_ONCE(cpu < 0 || cpu >= nr_cpu_ids, "%s: cpu = %d\n", __func__, cpu))
+		cpux = 0;
+	else
+		cpux = cpu;
+	cpu_cur_csd = smp_load_acquire(&per_cpu(cur_csd, cpux)); /* Before func and info. */
+	/* How long since this CSD lock was stuck. */
+	ts_delta = ts2 - ts0;
+	pr_alert("csd: %s non-responsive CSD lock (#%d) on CPU#%d, waiting %llu ns for CPU#%02d %pS(%ps).\n",
+		 firsttime ? "Detected" : "Continued", *bug_id, raw_smp_processor_id(), ts_delta,
+		 cpu, csd->func, csd->info);
+	/*
+	 * If the CSD lock is still stuck after 5 minutes, it is unlikely
+	 * to become unstuck. Use a signed comparison to avoid triggering
+	 * on underflows when the TSC is out of sync between sockets.
+	 */
+	BUG_ON(panic_on_ipistall > 0 && (s64)ts_delta > ((s64)panic_on_ipistall * NSEC_PER_MSEC));
+	if (cpu_cur_csd && csd != cpu_cur_csd) {
+		pr_alert("\tcsd: CSD lock (#%d) handling prior %pS(%ps) request.\n",
+			 *bug_id, READ_ONCE(per_cpu(cur_csd_func, cpux)),
+			 READ_ONCE(per_cpu(cur_csd_info, cpux)));
+	} else {
+		pr_alert("\tcsd: CSD lock (#%d) %s.\n",
+			 *bug_id, !cpu_cur_csd ? "unresponsive" : "handling this request");
+	}
+	if (cpu >= 0) {
+		if (static_branch_unlikely(&csdlock_debug_extended))
+			csd_lock_print_extended(csd, cpu);
+		dump_cpu_task(cpu);
+		if (!cpu_cur_csd) {
+			pr_alert("csd: Re-sending CSD lock (#%d) IPI from CPU#%02d to CPU#%02d\n", *bug_id, raw_smp_processor_id(), cpu);
+			arch_send_call_function_single_ipi(cpu);
+		}
+	}
+	dump_stack();
+	*ts1 = ts2;
+
+	return false;
+}
+
+/*
+ * csd_lock/csd_unlock used to serialize access to per-cpu csd resources
+ *
+ * For non-synchronous ipi calls the csd can still be in use by the
+ * previous function call. For multi-cpu calls its even more interesting
+ * as we'll have to ensure no other cpu is observing our csd.
+ */
+static void __csd_lock_wait(struct __call_single_data *csd)
+{
+	int bug_id = 0;
+	u64 ts0, ts1;
+
+	ts1 = ts0 = sched_clock();
+	for (;;) {
+		if (csd_lock_wait_toolong(csd, ts0, &ts1, &bug_id))
+			break;
+		cpu_relax();
+	}
+	smp_acquire__after_ctrl_dep();
+}
+
+static __always_inline void csd_lock_wait(struct __call_single_data *csd)
+{
+	if (static_branch_unlikely(&csdlock_debug_enabled)) {
+		__csd_lock_wait(csd);
+		return;
+	}
+
+	smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK));
+}
+
+static void __smp_call_single_queue_debug(int cpu, struct llist_node *node)
+{
+	unsigned int this_cpu = smp_processor_id();
+	struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
+	struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
+	struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+
+	cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
+	if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
+		cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
+		cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
+		send_call_function_single_ipi(cpu);
+		cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
+	} else {
+		cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
+	}
+}
+#else
+#define cfd_seq_store(var, src, dst, type)
+
+static void csd_lock_record(struct __call_single_data *csd)
+{
+}
+
+static __always_inline void csd_lock_wait(struct __call_single_data *csd)
+{
+	smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK));
+}
+#endif
+
+static __always_inline void csd_lock(struct __call_single_data *csd)
+{
+	csd_lock_wait(csd);
+	csd->node.u_flags |= CSD_FLAG_LOCK;
+
+	/*
+	 * prevent CPU from reordering the above assignment
+	 * to ->flags with any subsequent assignments to other
+	 * fields of the specified call_single_data_t structure:
+	 */
+	smp_wmb();
+}
+
+static __always_inline void csd_unlock(struct __call_single_data *csd)
+{
+	WARN_ON(!(csd->node.u_flags & CSD_FLAG_LOCK));
+
+	/*
+	 * ensure we're all done before releasing data:
+	 */
+	smp_store_release(&csd->node.u_flags, 0);
+}
+
+static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
+
+void __smp_call_single_queue(int cpu, struct llist_node *node)
+{
+#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+	if (static_branch_unlikely(&csdlock_debug_extended)) {
+		unsigned int type;
+
+		type = CSD_TYPE(container_of(node, call_single_data_t,
+					     node.llist));
+		if (type == CSD_TYPE_SYNC || type == CSD_TYPE_ASYNC) {
+			__smp_call_single_queue_debug(cpu, node);
+			return;
+		}
+	}
+#endif
+
+	/*
+	 * The list addition should be visible before sending the IPI
+	 * handler locks the list to pull the entry off it because of
+	 * normal cache coherency rules implied by spinlocks.
+	 *
+	 * If IPIs can go out of order to the cache coherency protocol
+	 * in an architecture, sufficient synchronisation should be added
+	 * to arch code to make it appear to obey cache coherency WRT
+	 * locking and barrier primitives. Generic code isn't really
+	 * equipped to do the right thing...
+	 */
+	if (llist_add(node, &per_cpu(call_single_queue, cpu)))
+		send_call_function_single_ipi(cpu);
+}
+
+/*
+ * Insert a previously allocated call_single_data_t element
+ * for execution on the given CPU. data must already have
+ * ->func, ->info, and ->flags set.
+ */
+static int generic_exec_single(int cpu, struct __call_single_data *csd)
+{
+	if (cpu == smp_processor_id()) {
+		smp_call_func_t func = csd->func;
+		void *info = csd->info;
+		unsigned long flags;
+
+		/*
+		 * We can unlock early even for the synchronous on-stack case,
+		 * since we're doing this from the same CPU..
+		 */
+		csd_lock_record(csd);
+		csd_unlock(csd);
+		local_irq_save(flags);
+		func(info);
+		csd_lock_record(NULL);
+		local_irq_restore(flags);
+		return 0;
+	}
+
+	if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) {
+		csd_unlock(csd);
+		return -ENXIO;
+	}
+
+	__smp_call_single_queue(cpu, &csd->node.llist);
+
+	return 0;
+}
+
+/**
+ * generic_smp_call_function_single_interrupt - Execute SMP IPI callbacks
+ *
+ * Invoked by arch to handle an IPI for call function single.
+ * Must be called with interrupts disabled.
+ */
+void generic_smp_call_function_single_interrupt(void)
+{
+	cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->gotipi, CFD_SEQ_NOCPU,
+		      smp_processor_id(), CFD_SEQ_GOTIPI);
+	__flush_smp_call_function_queue(true);
+}
+
+/**
+ * __flush_smp_call_function_queue - Flush pending smp-call-function callbacks
+ *
+ * @warn_cpu_offline: If set to 'true', warn if callbacks were queued on an
+ *		      offline CPU. Skip this check if set to 'false'.
+ *
+ * Flush any pending smp-call-function callbacks queued on this CPU. This is
+ * invoked by the generic IPI handler, as well as by a CPU about to go offline,
+ * to ensure that all pending IPI callbacks are run before it goes completely
+ * offline.
+ *
+ * Loop through the call_single_queue and run all the queued callbacks.
+ * Must be called with interrupts disabled.
+ */
+static void __flush_smp_call_function_queue(bool warn_cpu_offline)
+{
+	call_single_data_t *csd, *csd_next;
+	struct llist_node *entry, *prev;
+	struct llist_head *head;
+	static bool warned;
+
+	lockdep_assert_irqs_disabled();
+
+	head = this_cpu_ptr(&call_single_queue);
+	cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->handle, CFD_SEQ_NOCPU,
+		      smp_processor_id(), CFD_SEQ_HANDLE);
+	entry = llist_del_all(head);
+	cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->dequeue,
+		      /* Special meaning of source cpu: 0 == queue empty */
+		      entry ? CFD_SEQ_NOCPU : 0,
+		      smp_processor_id(), CFD_SEQ_DEQUEUE);
+	entry = llist_reverse_order(entry);
+
+	/* There shouldn't be any pending callbacks on an offline CPU. */
+	if (unlikely(warn_cpu_offline && !cpu_online(smp_processor_id()) &&
+		     !warned && entry != NULL)) {
+		warned = true;
+		WARN(1, "IPI on offline CPU %d\n", smp_processor_id());
+
+		/*
+		 * We don't have to use the _safe() variant here
+		 * because we are not invoking the IPI handlers yet.
+		 */
+		llist_for_each_entry(csd, entry, node.llist) {
+			switch (CSD_TYPE(csd)) {
+			case CSD_TYPE_ASYNC:
+			case CSD_TYPE_SYNC:
+			case CSD_TYPE_IRQ_WORK:
+				pr_warn("IPI callback %pS sent to offline CPU\n",
+					csd->func);
+				break;
+
+			case CSD_TYPE_TTWU:
+				pr_warn("IPI task-wakeup sent to offline CPU\n");
+				break;
+
+			default:
+				pr_warn("IPI callback, unknown type %d, sent to offline CPU\n",
+					CSD_TYPE(csd));
+				break;
+			}
+		}
+	}
+
+	/*
+	 * First; run all SYNC callbacks, people are waiting for us.
+	 */
+	prev = NULL;
+	llist_for_each_entry_safe(csd, csd_next, entry, node.llist) {
+		/* Do we wait until *after* callback? */
+		if (CSD_TYPE(csd) == CSD_TYPE_SYNC) {
+			smp_call_func_t func = csd->func;
+			void *info = csd->info;
+
+			if (prev) {
+				prev->next = &csd_next->node.llist;
+			} else {
+				entry = &csd_next->node.llist;
+			}
+
+			csd_lock_record(csd);
+			func(info);
+			csd_unlock(csd);
+			csd_lock_record(NULL);
+		} else {
+			prev = &csd->node.llist;
+		}
+	}
+
+	if (!entry) {
+		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->hdlend,
+			      0, smp_processor_id(),
+			      CFD_SEQ_HDLEND);
+		return;
+	}
+
+	/*
+	 * Second; run all !SYNC callbacks.
+	 */
+	prev = NULL;
+	llist_for_each_entry_safe(csd, csd_next, entry, node.llist) {
+		int type = CSD_TYPE(csd);
+
+		if (type != CSD_TYPE_TTWU) {
+			if (prev) {
+				prev->next = &csd_next->node.llist;
+			} else {
+				entry = &csd_next->node.llist;
+			}
+
+			if (type == CSD_TYPE_ASYNC) {
+				smp_call_func_t func = csd->func;
+				void *info = csd->info;
+
+				csd_lock_record(csd);
+				csd_unlock(csd);
+				func(info);
+				csd_lock_record(NULL);
+			} else if (type == CSD_TYPE_IRQ_WORK) {
+				irq_work_single(csd);
+			}
+
+		} else {
+			prev = &csd->node.llist;
+		}
+	}
+
+	/*
+	 * Third; only CSD_TYPE_TTWU is left, issue those.
+	 */
+	if (entry)
+		sched_ttwu_pending(entry);
+
+	cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->hdlend, CFD_SEQ_NOCPU,
+		      smp_processor_id(), CFD_SEQ_HDLEND);
+}
+
+
+/**
+ * flush_smp_call_function_queue - Flush pending smp-call-function callbacks
+ *				   from task context (idle, migration thread)
+ *
+ * When TIF_POLLING_NRFLAG is supported and a CPU is in idle and has it
+ * set, then remote CPUs can avoid sending IPIs and wake the idle CPU by
+ * setting TIF_NEED_RESCHED. The idle task on the woken up CPU has to
+ * handle queued SMP function calls before scheduling.
+ *
+ * The migration thread has to ensure that an eventually pending wakeup has
+ * been handled before it migrates a task.
+ */
+void flush_smp_call_function_queue(void)
+{
+	unsigned int was_pending;
+	unsigned long flags;
+
+	if (llist_empty(this_cpu_ptr(&call_single_queue)))
+		return;
+
+	cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->idle, CFD_SEQ_NOCPU,
+		      smp_processor_id(), CFD_SEQ_IDLE);
+	local_irq_save(flags);
+	/* Get the already pending soft interrupts for RT enabled kernels */
+	was_pending = local_softirq_pending();
+	__flush_smp_call_function_queue(true);
+	if (local_softirq_pending())
+		do_softirq_post_smp_call_flush(was_pending);
+
+	local_irq_restore(flags);
+}
+
+/*
+ * smp_call_function_single - Run a function on a specific CPU
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @wait: If true, wait until function has completed on other CPUs.
+ *
+ * Returns 0 on success, else a negative status code.
+ */
+int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
+			     int wait)
+{
+	call_single_data_t *csd;
+	call_single_data_t csd_stack = {
+		.node = { .u_flags = CSD_FLAG_LOCK | CSD_TYPE_SYNC, },
+	};
+	int this_cpu;
+	int err;
+
+	/*
+	 * prevent preemption and reschedule on another processor,
+	 * as well as CPU removal
+	 */
+	this_cpu = get_cpu();
+
+	/*
+	 * Can deadlock when called with interrupts disabled.
+	 * We allow cpu's that are not yet online though, as no one else can
+	 * send smp call function interrupt to this cpu and as such deadlocks
+	 * can't happen.
+	 */
+	WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
+		     && !oops_in_progress);
+
+	/*
+	 * When @wait we can deadlock when we interrupt between llist_add() and
+	 * arch_send_call_function_ipi*(); when !@wait we can deadlock due to
+	 * csd_lock() on because the interrupt context uses the same csd
+	 * storage.
+	 */
+	WARN_ON_ONCE(!in_task());
+
+	csd = &csd_stack;
+	if (!wait) {
+		csd = this_cpu_ptr(&csd_data);
+		csd_lock(csd);
+	}
+
+	csd->func = func;
+	csd->info = info;
+#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+	csd->node.src = smp_processor_id();
+	csd->node.dst = cpu;
+#endif
+
+	err = generic_exec_single(cpu, csd);
+
+	if (wait)
+		csd_lock_wait(csd);
+
+	put_cpu();
+
+	return err;
+}
+EXPORT_SYMBOL(smp_call_function_single);
+
+/**
+ * smp_call_function_single_async() - Run an asynchronous function on a
+ * 			         specific CPU.
+ * @cpu: The CPU to run on.
+ * @csd: Pre-allocated and setup data structure
+ *
+ * Like smp_call_function_single(), but the call is asynchonous and
+ * can thus be done from contexts with disabled interrupts.
+ *
+ * The caller passes his own pre-allocated data structure
+ * (ie: embedded in an object) and is responsible for synchronizing it
+ * such that the IPIs performed on the @csd are strictly serialized.
+ *
+ * If the function is called with one csd which has not yet been
+ * processed by previous call to smp_call_function_single_async(), the
+ * function will return immediately with -EBUSY showing that the csd
+ * object is still in progress.
+ *
+ * NOTE: Be careful, there is unfortunately no current debugging facility to
+ * validate the correctness of this serialization.
+ *
+ * Return: %0 on success or negative errno value on error
+ */
+int smp_call_function_single_async(int cpu, struct __call_single_data *csd)
+{
+	int err = 0;
+
+	preempt_disable();
+
+	if (csd->node.u_flags & CSD_FLAG_LOCK) {
+		err = -EBUSY;
+		goto out;
+	}
+
+	csd->node.u_flags = CSD_FLAG_LOCK;
+	smp_wmb();
+
+	err = generic_exec_single(cpu, csd);
+
+out:
+	preempt_enable();
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(smp_call_function_single_async);
+
+/*
+ * smp_call_function_any - Run a function on any of the given cpus
+ * @mask: The mask of cpus it can run on.
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @wait: If true, wait until function has completed.
+ *
+ * Returns 0 on success, else a negative status code (if no cpus were online).
+ *
+ * Selection preference:
+ *	1) current cpu if in @mask
+ *	2) any cpu of current node if in @mask
+ *	3) any other online cpu in @mask
+ */
+int smp_call_function_any(const struct cpumask *mask,
+			  smp_call_func_t func, void *info, int wait)
+{
+	unsigned int cpu;
+	const struct cpumask *nodemask;
+	int ret;
+
+	/* Try for same CPU (cheapest) */
+	cpu = get_cpu();
+	if (cpumask_test_cpu(cpu, mask))
+		goto call;
+
+	/* Try for same node. */
+	nodemask = cpumask_of_node(cpu_to_node(cpu));
+	for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids;
+	     cpu = cpumask_next_and(cpu, nodemask, mask)) {
+		if (cpu_online(cpu))
+			goto call;
+	}
+
+	/* Any online will do: smp_call_function_single handles nr_cpu_ids. */
+	cpu = cpumask_any_and(mask, cpu_online_mask);
+call:
+	ret = smp_call_function_single(cpu, func, info, wait);
+	put_cpu();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(smp_call_function_any);
+
+/*
+ * Flags to be used as scf_flags argument of smp_call_function_many_cond().
+ *
+ * %SCF_WAIT:		Wait until function execution is completed
+ * %SCF_RUN_LOCAL:	Run also locally if local cpu is set in cpumask
+ */
+#define SCF_WAIT	(1U << 0)
+#define SCF_RUN_LOCAL	(1U << 1)
+
+static void smp_call_function_many_cond(const struct cpumask *mask,
+					smp_call_func_t func, void *info,
+					unsigned int scf_flags,
+					smp_cond_func_t cond_func)
+{
+	int cpu, last_cpu, this_cpu = smp_processor_id();
+	struct call_function_data *cfd;
+	bool wait = scf_flags & SCF_WAIT;
+	bool run_remote = false;
+	bool run_local = false;
+	int nr_cpus = 0;
+
+	lockdep_assert_preemption_disabled();
+
+	/*
+	 * Can deadlock when called with interrupts disabled.
+	 * We allow cpu's that are not yet online though, as no one else can
+	 * send smp call function interrupt to this cpu and as such deadlocks
+	 * can't happen.
+	 */
+	if (cpu_online(this_cpu) && !oops_in_progress &&
+	    !early_boot_irqs_disabled)
+		lockdep_assert_irqs_enabled();
+
+	/*
+	 * When @wait we can deadlock when we interrupt between llist_add() and
+	 * arch_send_call_function_ipi*(); when !@wait we can deadlock due to
+	 * csd_lock() on because the interrupt context uses the same csd
+	 * storage.
+	 */
+	WARN_ON_ONCE(!in_task());
+
+	/* Check if we need local execution. */
+	if ((scf_flags & SCF_RUN_LOCAL) && cpumask_test_cpu(this_cpu, mask))
+		run_local = true;
+
+	/* Check if we need remote execution, i.e., any CPU excluding this one. */
+	cpu = cpumask_first_and(mask, cpu_online_mask);
+	if (cpu == this_cpu)
+		cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
+	if (cpu < nr_cpu_ids)
+		run_remote = true;
+
+	if (run_remote) {
+		cfd = this_cpu_ptr(&cfd_data);
+		cpumask_and(cfd->cpumask, mask, cpu_online_mask);
+		__cpumask_clear_cpu(this_cpu, cfd->cpumask);
+
+		cpumask_clear(cfd->cpumask_ipi);
+		for_each_cpu(cpu, cfd->cpumask) {
+			struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+			call_single_data_t *csd = &pcpu->csd;
+
+			if (cond_func && !cond_func(cpu, info))
+				continue;
+
+			csd_lock(csd);
+			if (wait)
+				csd->node.u_flags |= CSD_TYPE_SYNC;
+			csd->func = func;
+			csd->info = info;
+#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+			csd->node.src = smp_processor_id();
+			csd->node.dst = cpu;
+#endif
+			cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
+			if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) {
+				__cpumask_set_cpu(cpu, cfd->cpumask_ipi);
+				nr_cpus++;
+				last_cpu = cpu;
+
+				cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
+			} else {
+				cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
+			}
+		}
+
+		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->ping, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PING);
+
+		/*
+		 * Choose the most efficient way to send an IPI. Note that the
+		 * number of CPUs might be zero due to concurrent changes to the
+		 * provided mask.
+		 */
+		if (nr_cpus == 1)
+			send_call_function_single_ipi(last_cpu);
+		else if (likely(nr_cpus > 1))
+			arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
+
+		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
+	}
+
+	if (run_local && (!cond_func || cond_func(this_cpu, info))) {
+		unsigned long flags;
+
+		local_irq_save(flags);
+		func(info);
+		local_irq_restore(flags);
+	}
+
+	if (run_remote && wait) {
+		for_each_cpu(cpu, cfd->cpumask) {
+			call_single_data_t *csd;
+
+			csd = &per_cpu_ptr(cfd->pcpu, cpu)->csd;
+			csd_lock_wait(csd);
+		}
+	}
+}
+
+/**
+ * smp_call_function_many(): Run a function on a set of CPUs.
+ * @mask: The set of cpus to run on (only runs on online subset).
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @wait: Bitmask that controls the operation. If %SCF_WAIT is set, wait
+ *        (atomically) until function has completed on other CPUs. If
+ *        %SCF_RUN_LOCAL is set, the function will also be run locally
+ *        if the local CPU is set in the @cpumask.
+ *
+ * If @wait is true, then returns once @func has returned.
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler or from a bottom half handler. Preemption
+ * must be disabled when calling this function.
+ */
+void smp_call_function_many(const struct cpumask *mask,
+			    smp_call_func_t func, void *info, bool wait)
+{
+	smp_call_function_many_cond(mask, func, info, wait * SCF_WAIT, NULL);
+}
+EXPORT_SYMBOL(smp_call_function_many);
+
+/**
+ * smp_call_function(): Run a function on all other CPUs.
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @wait: If true, wait (atomically) until function has completed
+ *        on other CPUs.
+ *
+ * Returns 0.
+ *
+ * If @wait is true, then returns once @func has returned; otherwise
+ * it returns just before the target cpu calls @func.
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler or from a bottom half handler.
+ */
+void smp_call_function(smp_call_func_t func, void *info, int wait)
+{
+	preempt_disable();
+	smp_call_function_many(cpu_online_mask, func, info, wait);
+	preempt_enable();
+}
+EXPORT_SYMBOL(smp_call_function);
+
+/* Setup configured maximum number of CPUs to activate */
+unsigned int setup_max_cpus = NR_CPUS;
+EXPORT_SYMBOL(setup_max_cpus);
+
+
+/*
+ * Setup routine for controlling SMP activation
+ *
+ * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
+ * activation entirely (the MPS table probe still happens, though).
+ *
+ * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
+ * greater than 0, limits the maximum number of CPUs activated in
+ * SMP mode to <NUM>.
+ */
+
+void __weak arch_disable_smp_support(void) { }
+
+static int __init nosmp(char *str)
+{
+	setup_max_cpus = 0;
+	arch_disable_smp_support();
+
+	return 0;
+}
+
+early_param("nosmp", nosmp);
+
+/* this is hard limit */
+static int __init nrcpus(char *str)
+{
+	int nr_cpus;
+
+	if (get_option(&str, &nr_cpus) && nr_cpus > 0 && nr_cpus < nr_cpu_ids)
+		set_nr_cpu_ids(nr_cpus);
+
+	return 0;
+}
+
+early_param("nr_cpus", nrcpus);
+
+static int __init maxcpus(char *str)
+{
+	get_option(&str, &setup_max_cpus);
+	if (setup_max_cpus == 0)
+		arch_disable_smp_support();
+
+	return 0;
+}
+
+early_param("maxcpus", maxcpus);
+
+#if (NR_CPUS > 1) && !defined(CONFIG_FORCE_NR_CPUS)
+/* Setup number of possible processor ids */
+unsigned int nr_cpu_ids __read_mostly = NR_CPUS;
+EXPORT_SYMBOL(nr_cpu_ids);
+#endif
+
+/* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
+void __init setup_nr_cpu_ids(void)
+{
+	set_nr_cpu_ids(find_last_bit(cpumask_bits(cpu_possible_mask), NR_CPUS) + 1);
+}
+
+/* Called by boot processor to activate the rest. */
+void __init smp_init(void)
+{
+	int num_nodes, num_cpus;
+
+	idle_threads_init();
+	cpuhp_threads_init();
+
+	pr_info("Bringing up secondary CPUs ...\n");
+
+	bringup_nonboot_cpus(setup_max_cpus);
+
+	num_nodes = num_online_nodes();
+	num_cpus  = num_online_cpus();
+	pr_info("Brought up %d node%s, %d CPU%s\n",
+		num_nodes, (num_nodes > 1 ? "s" : ""),
+		num_cpus,  (num_cpus  > 1 ? "s" : ""));
+
+	/* Any cleanup work */
+	smp_cpus_done(setup_max_cpus);
+}
+
+/*
+ * on_each_cpu_cond(): Call a function on each processor for which
+ * the supplied function cond_func returns true, optionally waiting
+ * for all the required CPUs to finish. This may include the local
+ * processor.
+ * @cond_func:	A callback function that is passed a cpu id and
+ *		the info parameter. The function is called
+ *		with preemption disabled. The function should
+ *		return a blooean value indicating whether to IPI
+ *		the specified CPU.
+ * @func:	The function to run on all applicable CPUs.
+ *		This must be fast and non-blocking.
+ * @info:	An arbitrary pointer to pass to both functions.
+ * @wait:	If true, wait (atomically) until function has
+ *		completed on other CPUs.
+ *
+ * Preemption is disabled to protect against CPUs going offline but not online.
+ * CPUs going online during the call will not be seen or sent an IPI.
+ *
+ * You must not call this function with disabled interrupts or
+ * from a hardware interrupt handler or from a bottom half handler.
+ */
+void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
+			   void *info, bool wait, const struct cpumask *mask)
+{
+	unsigned int scf_flags = SCF_RUN_LOCAL;
+
+	if (wait)
+		scf_flags |= SCF_WAIT;
+
+	preempt_disable();
+	smp_call_function_many_cond(mask, func, info, scf_flags, cond_func);
+	preempt_enable();
+}
+EXPORT_SYMBOL(on_each_cpu_cond_mask);
+
+static void do_nothing(void *unused)
+{
+}
+
+/**
+ * kick_all_cpus_sync - Force all cpus out of idle
+ *
+ * Used to synchronize the update of pm_idle function pointer. It's
+ * called after the pointer is updated and returns after the dummy
+ * callback function has been executed on all cpus. The execution of
+ * the function can only happen on the remote cpus after they have
+ * left the idle function which had been called via pm_idle function
+ * pointer. So it's guaranteed that nothing uses the previous pointer
+ * anymore.
+ */
+void kick_all_cpus_sync(void)
+{
+	/* Make sure the change is visible before we kick the cpus */
+	smp_mb();
+	smp_call_function(do_nothing, NULL, 1);
+}
+EXPORT_SYMBOL_GPL(kick_all_cpus_sync);
+
+/**
+ * wake_up_all_idle_cpus - break all cpus out of idle
+ * wake_up_all_idle_cpus try to break all cpus which is in idle state even
+ * including idle polling cpus, for non-idle cpus, we will do nothing
+ * for them.
+ */
+void wake_up_all_idle_cpus(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		preempt_disable();
+		if (cpu != smp_processor_id() && cpu_online(cpu))
+			wake_up_if_idle(cpu);
+		preempt_enable();
+	}
+}
+EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus);
+
+/**
+ * struct smp_call_on_cpu_struct - Call a function on a specific CPU
+ * @work: &work_struct
+ * @done: &completion to signal
+ * @func: function to call
+ * @data: function's data argument
+ * @ret: return value from @func
+ * @cpu: target CPU (%-1 for any CPU)
+ *
+ * Used to call a function on a specific cpu and wait for it to return.
+ * Optionally make sure the call is done on a specified physical cpu via vcpu
+ * pinning in order to support virtualized environments.
+ */
+struct smp_call_on_cpu_struct {
+	struct work_struct	work;
+	struct completion	done;
+	int			(*func)(void *);
+	void			*data;
+	int			ret;
+	int			cpu;
+};
+
+static void smp_call_on_cpu_callback(struct work_struct *work)
+{
+	struct smp_call_on_cpu_struct *sscs;
+
+	sscs = container_of(work, struct smp_call_on_cpu_struct, work);
+	if (sscs->cpu >= 0)
+		hypervisor_pin_vcpu(sscs->cpu);
+	sscs->ret = sscs->func(sscs->data);
+	if (sscs->cpu >= 0)
+		hypervisor_pin_vcpu(-1);
+
+	complete(&sscs->done);
+}
+
+int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
+{
+	struct smp_call_on_cpu_struct sscs = {
+		.done = COMPLETION_INITIALIZER_ONSTACK(sscs.done),
+		.func = func,
+		.data = par,
+		.cpu  = phys ? cpu : -1,
+	};
+
+	INIT_WORK_ONSTACK(&sscs.work, smp_call_on_cpu_callback);
+
+	if (cpu >= nr_cpu_ids || !cpu_online(cpu))
+		return -ENXIO;
+
+	queue_work_on(cpu, system_wq, &sscs.work);
+	wait_for_completion(&sscs.done);
+
+	return sscs.ret;
+}
+EXPORT_SYMBOL_GPL(smp_call_on_cpu);
diff --git a/kernel/smpboot.c b/kernel/smpboot.c
new file mode 100644
index 000000000..2c7396da4
--- /dev/null
+++ b/kernel/smpboot.c
@@ -0,0 +1,490 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Common SMP CPU bringup/teardown functions
+ */
+#include <linux/cpu.h>
+#include <linux/err.h>
+#include <linux/smp.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/export.h>
+#include <linux/percpu.h>
+#include <linux/kthread.h>
+#include <linux/smpboot.h>
+
+#include "smpboot.h"
+
+#ifdef CONFIG_SMP
+
+#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
+/*
+ * For the hotplug case we keep the task structs around and reuse
+ * them.
+ */
+static DEFINE_PER_CPU(struct task_struct *, idle_threads);
+
+struct task_struct *idle_thread_get(unsigned int cpu)
+{
+	struct task_struct *tsk = per_cpu(idle_threads, cpu);
+
+	if (!tsk)
+		return ERR_PTR(-ENOMEM);
+	return tsk;
+}
+
+void __init idle_thread_set_boot_cpu(void)
+{
+	per_cpu(idle_threads, smp_processor_id()) = current;
+}
+
+/**
+ * idle_init - Initialize the idle thread for a cpu
+ * @cpu:	The cpu for which the idle thread should be initialized
+ *
+ * Creates the thread if it does not exist.
+ */
+static __always_inline void idle_init(unsigned int cpu)
+{
+	struct task_struct *tsk = per_cpu(idle_threads, cpu);
+
+	if (!tsk) {
+		tsk = fork_idle(cpu);
+		if (IS_ERR(tsk))
+			pr_err("SMP: fork_idle() failed for CPU %u\n", cpu);
+		else
+			per_cpu(idle_threads, cpu) = tsk;
+	}
+}
+
+/**
+ * idle_threads_init - Initialize idle threads for all cpus
+ */
+void __init idle_threads_init(void)
+{
+	unsigned int cpu, boot_cpu;
+
+	boot_cpu = smp_processor_id();
+
+	for_each_possible_cpu(cpu) {
+		if (cpu != boot_cpu)
+			idle_init(cpu);
+	}
+}
+#endif
+
+#endif /* #ifdef CONFIG_SMP */
+
+static LIST_HEAD(hotplug_threads);
+static DEFINE_MUTEX(smpboot_threads_lock);
+
+struct smpboot_thread_data {
+	unsigned int			cpu;
+	unsigned int			status;
+	struct smp_hotplug_thread	*ht;
+};
+
+enum {
+	HP_THREAD_NONE = 0,
+	HP_THREAD_ACTIVE,
+	HP_THREAD_PARKED,
+};
+
+/**
+ * smpboot_thread_fn - percpu hotplug thread loop function
+ * @data:	thread data pointer
+ *
+ * Checks for thread stop and park conditions. Calls the necessary
+ * setup, cleanup, park and unpark functions for the registered
+ * thread.
+ *
+ * Returns 1 when the thread should exit, 0 otherwise.
+ */
+static int smpboot_thread_fn(void *data)
+{
+	struct smpboot_thread_data *td = data;
+	struct smp_hotplug_thread *ht = td->ht;
+
+	while (1) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		preempt_disable();
+		if (kthread_should_stop()) {
+			__set_current_state(TASK_RUNNING);
+			preempt_enable();
+			/* cleanup must mirror setup */
+			if (ht->cleanup && td->status != HP_THREAD_NONE)
+				ht->cleanup(td->cpu, cpu_online(td->cpu));
+			kfree(td);
+			return 0;
+		}
+
+		if (kthread_should_park()) {
+			__set_current_state(TASK_RUNNING);
+			preempt_enable();
+			if (ht->park && td->status == HP_THREAD_ACTIVE) {
+				BUG_ON(td->cpu != smp_processor_id());
+				ht->park(td->cpu);
+				td->status = HP_THREAD_PARKED;
+			}
+			kthread_parkme();
+			/* We might have been woken for stop */
+			continue;
+		}
+
+		BUG_ON(td->cpu != smp_processor_id());
+
+		/* Check for state change setup */
+		switch (td->status) {
+		case HP_THREAD_NONE:
+			__set_current_state(TASK_RUNNING);
+			preempt_enable();
+			if (ht->setup)
+				ht->setup(td->cpu);
+			td->status = HP_THREAD_ACTIVE;
+			continue;
+
+		case HP_THREAD_PARKED:
+			__set_current_state(TASK_RUNNING);
+			preempt_enable();
+			if (ht->unpark)
+				ht->unpark(td->cpu);
+			td->status = HP_THREAD_ACTIVE;
+			continue;
+		}
+
+		if (!ht->thread_should_run(td->cpu)) {
+			preempt_enable_no_resched();
+			schedule();
+		} else {
+			__set_current_state(TASK_RUNNING);
+			preempt_enable();
+			ht->thread_fn(td->cpu);
+		}
+	}
+}
+
+static int
+__smpboot_create_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
+{
+	struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
+	struct smpboot_thread_data *td;
+
+	if (tsk)
+		return 0;
+
+	td = kzalloc_node(sizeof(*td), GFP_KERNEL, cpu_to_node(cpu));
+	if (!td)
+		return -ENOMEM;
+	td->cpu = cpu;
+	td->ht = ht;
+
+	tsk = kthread_create_on_cpu(smpboot_thread_fn, td, cpu,
+				    ht->thread_comm);
+	if (IS_ERR(tsk)) {
+		kfree(td);
+		return PTR_ERR(tsk);
+	}
+	kthread_set_per_cpu(tsk, cpu);
+	/*
+	 * Park the thread so that it could start right on the CPU
+	 * when it is available.
+	 */
+	kthread_park(tsk);
+	get_task_struct(tsk);
+	*per_cpu_ptr(ht->store, cpu) = tsk;
+	if (ht->create) {
+		/*
+		 * Make sure that the task has actually scheduled out
+		 * into park position, before calling the create
+		 * callback. At least the migration thread callback
+		 * requires that the task is off the runqueue.
+		 */
+		if (!wait_task_inactive(tsk, TASK_PARKED))
+			WARN_ON(1);
+		else
+			ht->create(cpu);
+	}
+	return 0;
+}
+
+int smpboot_create_threads(unsigned int cpu)
+{
+	struct smp_hotplug_thread *cur;
+	int ret = 0;
+
+	mutex_lock(&smpboot_threads_lock);
+	list_for_each_entry(cur, &hotplug_threads, list) {
+		ret = __smpboot_create_thread(cur, cpu);
+		if (ret)
+			break;
+	}
+	mutex_unlock(&smpboot_threads_lock);
+	return ret;
+}
+
+static void smpboot_unpark_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
+{
+	struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
+
+	if (!ht->selfparking)
+		kthread_unpark(tsk);
+}
+
+int smpboot_unpark_threads(unsigned int cpu)
+{
+	struct smp_hotplug_thread *cur;
+
+	mutex_lock(&smpboot_threads_lock);
+	list_for_each_entry(cur, &hotplug_threads, list)
+		smpboot_unpark_thread(cur, cpu);
+	mutex_unlock(&smpboot_threads_lock);
+	return 0;
+}
+
+static void smpboot_park_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
+{
+	struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
+
+	if (tsk && !ht->selfparking)
+		kthread_park(tsk);
+}
+
+int smpboot_park_threads(unsigned int cpu)
+{
+	struct smp_hotplug_thread *cur;
+
+	mutex_lock(&smpboot_threads_lock);
+	list_for_each_entry_reverse(cur, &hotplug_threads, list)
+		smpboot_park_thread(cur, cpu);
+	mutex_unlock(&smpboot_threads_lock);
+	return 0;
+}
+
+static void smpboot_destroy_threads(struct smp_hotplug_thread *ht)
+{
+	unsigned int cpu;
+
+	/* We need to destroy also the parked threads of offline cpus */
+	for_each_possible_cpu(cpu) {
+		struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
+
+		if (tsk) {
+			kthread_stop(tsk);
+			put_task_struct(tsk);
+			*per_cpu_ptr(ht->store, cpu) = NULL;
+		}
+	}
+}
+
+/**
+ * smpboot_register_percpu_thread - Register a per_cpu thread related
+ * 					    to hotplug
+ * @plug_thread:	Hotplug thread descriptor
+ *
+ * Creates and starts the threads on all online cpus.
+ */
+int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread)
+{
+	unsigned int cpu;
+	int ret = 0;
+
+	cpus_read_lock();
+	mutex_lock(&smpboot_threads_lock);
+	for_each_online_cpu(cpu) {
+		ret = __smpboot_create_thread(plug_thread, cpu);
+		if (ret) {
+			smpboot_destroy_threads(plug_thread);
+			goto out;
+		}
+		smpboot_unpark_thread(plug_thread, cpu);
+	}
+	list_add(&plug_thread->list, &hotplug_threads);
+out:
+	mutex_unlock(&smpboot_threads_lock);
+	cpus_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(smpboot_register_percpu_thread);
+
+/**
+ * smpboot_unregister_percpu_thread - Unregister a per_cpu thread related to hotplug
+ * @plug_thread:	Hotplug thread descriptor
+ *
+ * Stops all threads on all possible cpus.
+ */
+void smpboot_unregister_percpu_thread(struct smp_hotplug_thread *plug_thread)
+{
+	cpus_read_lock();
+	mutex_lock(&smpboot_threads_lock);
+	list_del(&plug_thread->list);
+	smpboot_destroy_threads(plug_thread);
+	mutex_unlock(&smpboot_threads_lock);
+	cpus_read_unlock();
+}
+EXPORT_SYMBOL_GPL(smpboot_unregister_percpu_thread);
+
+static DEFINE_PER_CPU(atomic_t, cpu_hotplug_state) = ATOMIC_INIT(CPU_POST_DEAD);
+
+/*
+ * Called to poll specified CPU's state, for example, when waiting for
+ * a CPU to come online.
+ */
+int cpu_report_state(int cpu)
+{
+	return atomic_read(&per_cpu(cpu_hotplug_state, cpu));
+}
+
+/*
+ * If CPU has died properly, set its state to CPU_UP_PREPARE and
+ * return success.  Otherwise, return -EBUSY if the CPU died after
+ * cpu_wait_death() timed out.  And yet otherwise again, return -EAGAIN
+ * if cpu_wait_death() timed out and the CPU still hasn't gotten around
+ * to dying.  In the latter two cases, the CPU might not be set up
+ * properly, but it is up to the arch-specific code to decide.
+ * Finally, -EIO indicates an unanticipated problem.
+ *
+ * Note that it is permissible to omit this call entirely, as is
+ * done in architectures that do no CPU-hotplug error checking.
+ */
+int cpu_check_up_prepare(int cpu)
+{
+	if (!IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
+		atomic_set(&per_cpu(cpu_hotplug_state, cpu), CPU_UP_PREPARE);
+		return 0;
+	}
+
+	switch (atomic_read(&per_cpu(cpu_hotplug_state, cpu))) {
+
+	case CPU_POST_DEAD:
+
+		/* The CPU died properly, so just start it up again. */
+		atomic_set(&per_cpu(cpu_hotplug_state, cpu), CPU_UP_PREPARE);
+		return 0;
+
+	case CPU_DEAD_FROZEN:
+
+		/*
+		 * Timeout during CPU death, so let caller know.
+		 * The outgoing CPU completed its processing, but after
+		 * cpu_wait_death() timed out and reported the error. The
+		 * caller is free to proceed, in which case the state
+		 * will be reset properly by cpu_set_state_online().
+		 * Proceeding despite this -EBUSY return makes sense
+		 * for systems where the outgoing CPUs take themselves
+		 * offline, with no post-death manipulation required from
+		 * a surviving CPU.
+		 */
+		return -EBUSY;
+
+	case CPU_BROKEN:
+
+		/*
+		 * The most likely reason we got here is that there was
+		 * a timeout during CPU death, and the outgoing CPU never
+		 * did complete its processing.  This could happen on
+		 * a virtualized system if the outgoing VCPU gets preempted
+		 * for more than five seconds, and the user attempts to
+		 * immediately online that same CPU.  Trying again later
+		 * might return -EBUSY above, hence -EAGAIN.
+		 */
+		return -EAGAIN;
+
+	case CPU_UP_PREPARE:
+		/*
+		 * Timeout while waiting for the CPU to show up. Allow to try
+		 * again later.
+		 */
+		return 0;
+
+	default:
+
+		/* Should not happen.  Famous last words. */
+		return -EIO;
+	}
+}
+
+/*
+ * Mark the specified CPU online.
+ *
+ * Note that it is permissible to omit this call entirely, as is
+ * done in architectures that do no CPU-hotplug error checking.
+ */
+void cpu_set_state_online(int cpu)
+{
+	(void)atomic_xchg(&per_cpu(cpu_hotplug_state, cpu), CPU_ONLINE);
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+/*
+ * Wait for the specified CPU to exit the idle loop and die.
+ */
+bool cpu_wait_death(unsigned int cpu, int seconds)
+{
+	int jf_left = seconds * HZ;
+	int oldstate;
+	bool ret = true;
+	int sleep_jf = 1;
+
+	might_sleep();
+
+	/* The outgoing CPU will normally get done quite quickly. */
+	if (atomic_read(&per_cpu(cpu_hotplug_state, cpu)) == CPU_DEAD)
+		goto update_state_early;
+	udelay(5);
+
+	/* But if the outgoing CPU dawdles, wait increasingly long times. */
+	while (atomic_read(&per_cpu(cpu_hotplug_state, cpu)) != CPU_DEAD) {
+		schedule_timeout_uninterruptible(sleep_jf);
+		jf_left -= sleep_jf;
+		if (jf_left <= 0)
+			break;
+		sleep_jf = DIV_ROUND_UP(sleep_jf * 11, 10);
+	}
+update_state_early:
+	oldstate = atomic_read(&per_cpu(cpu_hotplug_state, cpu));
+update_state:
+	if (oldstate == CPU_DEAD) {
+		/* Outgoing CPU died normally, update state. */
+		smp_mb(); /* atomic_read() before update. */
+		atomic_set(&per_cpu(cpu_hotplug_state, cpu), CPU_POST_DEAD);
+	} else {
+		/* Outgoing CPU still hasn't died, set state accordingly. */
+		if (!atomic_try_cmpxchg(&per_cpu(cpu_hotplug_state, cpu),
+					&oldstate, CPU_BROKEN))
+			goto update_state;
+		ret = false;
+	}
+	return ret;
+}
+
+/*
+ * Called by the outgoing CPU to report its successful death.  Return
+ * false if this report follows the surviving CPU's timing out.
+ *
+ * A separate "CPU_DEAD_FROZEN" is used when the surviving CPU
+ * timed out.  This approach allows architectures to omit calls to
+ * cpu_check_up_prepare() and cpu_set_state_online() without defeating
+ * the next cpu_wait_death()'s polling loop.
+ */
+bool cpu_report_death(void)
+{
+	int oldstate;
+	int newstate;
+	int cpu = smp_processor_id();
+
+	oldstate = atomic_read(&per_cpu(cpu_hotplug_state, cpu));
+	do {
+		if (oldstate != CPU_BROKEN)
+			newstate = CPU_DEAD;
+		else
+			newstate = CPU_DEAD_FROZEN;
+	} while (!atomic_try_cmpxchg(&per_cpu(cpu_hotplug_state, cpu),
+				     &oldstate, newstate));
+	return newstate == CPU_DEAD;
+}
+
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
diff --git a/kernel/smpboot.h b/kernel/smpboot.h
new file mode 100644
index 000000000..34dd3d7ba
--- /dev/null
+++ b/kernel/smpboot.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef SMPBOOT_H
+#define SMPBOOT_H
+
+struct task_struct;
+
+#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
+struct task_struct *idle_thread_get(unsigned int cpu);
+void idle_thread_set_boot_cpu(void);
+void idle_threads_init(void);
+#else
+static inline struct task_struct *idle_thread_get(unsigned int cpu) { return NULL; }
+static inline void idle_thread_set_boot_cpu(void) { }
+static inline void idle_threads_init(void) { }
+#endif
+
+int smpboot_create_threads(unsigned int cpu);
+int smpboot_park_threads(unsigned int cpu);
+int smpboot_unpark_threads(unsigned int cpu);
+
+void __init cpuhp_threads_init(void);
+
+#endif
diff --git a/kernel/softirq.c b/kernel/softirq.c
new file mode 100644
index 000000000..c8a6913c0
--- /dev/null
+++ b/kernel/softirq.c
@@ -0,0 +1,1012 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *	linux/kernel/softirq.c
+ *
+ *	Copyright (C) 1992 Linus Torvalds
+ *
+ *	Rewritten. Old one was good in 2.2, but in 2.3 it was immoral. --ANK (990903)
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/export.h>
+#include <linux/kernel_stat.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/local_lock.h>
+#include <linux/mm.h>
+#include <linux/notifier.h>
+#include <linux/percpu.h>
+#include <linux/cpu.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
+#include <linux/rcupdate.h>
+#include <linux/ftrace.h>
+#include <linux/smp.h>
+#include <linux/smpboot.h>
+#include <linux/tick.h>
+#include <linux/irq.h>
+#include <linux/wait_bit.h>
+
+#include <asm/softirq_stack.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/irq.h>
+
+/*
+   - No shared variables, all the data are CPU local.
+   - If a softirq needs serialization, let it serialize itself
+     by its own spinlocks.
+   - Even if softirq is serialized, only local cpu is marked for
+     execution. Hence, we get something sort of weak cpu binding.
+     Though it is still not clear, will it result in better locality
+     or will not.
+
+   Examples:
+   - NET RX softirq. It is multithreaded and does not require
+     any global serialization.
+   - NET TX softirq. It kicks software netdevice queues, hence
+     it is logically serialized per device, but this serialization
+     is invisible to common code.
+   - Tasklets: serialized wrt itself.
+ */
+
+#ifndef __ARCH_IRQ_STAT
+DEFINE_PER_CPU_ALIGNED(irq_cpustat_t, irq_stat);
+EXPORT_PER_CPU_SYMBOL(irq_stat);
+#endif
+
+static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp;
+
+DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
+
+const char * const softirq_to_name[NR_SOFTIRQS] = {
+	"HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "IRQ_POLL",
+	"TASKLET", "SCHED", "HRTIMER", "RCU"
+};
+
+/*
+ * we cannot loop indefinitely here to avoid userspace starvation,
+ * but we also don't want to introduce a worst case 1/HZ latency
+ * to the pending events, so lets the scheduler to balance
+ * the softirq load for us.
+ */
+static void wakeup_softirqd(void)
+{
+	/* Interrupts are disabled: no need to stop preemption */
+	struct task_struct *tsk = __this_cpu_read(ksoftirqd);
+
+	if (tsk)
+		wake_up_process(tsk);
+}
+
+/*
+ * If ksoftirqd is scheduled, we do not want to process pending softirqs
+ * right now. Let ksoftirqd handle this at its own rate, to get fairness,
+ * unless we're doing some of the synchronous softirqs.
+ */
+#define SOFTIRQ_NOW_MASK ((1 << HI_SOFTIRQ) | (1 << TASKLET_SOFTIRQ))
+static bool ksoftirqd_running(unsigned long pending)
+{
+	struct task_struct *tsk = __this_cpu_read(ksoftirqd);
+
+	if (pending & SOFTIRQ_NOW_MASK)
+		return false;
+	return tsk && task_is_running(tsk) && !__kthread_should_park(tsk);
+}
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+DEFINE_PER_CPU(int, hardirqs_enabled);
+DEFINE_PER_CPU(int, hardirq_context);
+EXPORT_PER_CPU_SYMBOL_GPL(hardirqs_enabled);
+EXPORT_PER_CPU_SYMBOL_GPL(hardirq_context);
+#endif
+
+/*
+ * SOFTIRQ_OFFSET usage:
+ *
+ * On !RT kernels 'count' is the preempt counter, on RT kernels this applies
+ * to a per CPU counter and to task::softirqs_disabled_cnt.
+ *
+ * - count is changed by SOFTIRQ_OFFSET on entering or leaving softirq
+ *   processing.
+ *
+ * - count is changed by SOFTIRQ_DISABLE_OFFSET (= 2 * SOFTIRQ_OFFSET)
+ *   on local_bh_disable or local_bh_enable.
+ *
+ * This lets us distinguish between whether we are currently processing
+ * softirq and whether we just have bh disabled.
+ */
+#ifdef CONFIG_PREEMPT_RT
+
+/*
+ * RT accounts for BH disabled sections in task::softirqs_disabled_cnt and
+ * also in per CPU softirq_ctrl::cnt. This is necessary to allow tasks in a
+ * softirq disabled section to be preempted.
+ *
+ * The per task counter is used for softirq_count(), in_softirq() and
+ * in_serving_softirqs() because these counts are only valid when the task
+ * holding softirq_ctrl::lock is running.
+ *
+ * The per CPU counter prevents pointless wakeups of ksoftirqd in case that
+ * the task which is in a softirq disabled section is preempted or blocks.
+ */
+struct softirq_ctrl {
+	local_lock_t	lock;
+	int		cnt;
+};
+
+static DEFINE_PER_CPU(struct softirq_ctrl, softirq_ctrl) = {
+	.lock	= INIT_LOCAL_LOCK(softirq_ctrl.lock),
+};
+
+/**
+ * local_bh_blocked() - Check for idle whether BH processing is blocked
+ *
+ * Returns false if the per CPU softirq::cnt is 0 otherwise true.
+ *
+ * This is invoked from the idle task to guard against false positive
+ * softirq pending warnings, which would happen when the task which holds
+ * softirq_ctrl::lock was the only running task on the CPU and blocks on
+ * some other lock.
+ */
+bool local_bh_blocked(void)
+{
+	return __this_cpu_read(softirq_ctrl.cnt) != 0;
+}
+
+void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
+{
+	unsigned long flags;
+	int newcnt;
+
+	WARN_ON_ONCE(in_hardirq());
+
+	/* First entry of a task into a BH disabled section? */
+	if (!current->softirq_disable_cnt) {
+		if (preemptible()) {
+			local_lock(&softirq_ctrl.lock);
+			/* Required to meet the RCU bottomhalf requirements. */
+			rcu_read_lock();
+		} else {
+			DEBUG_LOCKS_WARN_ON(this_cpu_read(softirq_ctrl.cnt));
+		}
+	}
+
+	/*
+	 * Track the per CPU softirq disabled state. On RT this is per CPU
+	 * state to allow preemption of bottom half disabled sections.
+	 */
+	newcnt = __this_cpu_add_return(softirq_ctrl.cnt, cnt);
+	/*
+	 * Reflect the result in the task state to prevent recursion on the
+	 * local lock and to make softirq_count() & al work.
+	 */
+	current->softirq_disable_cnt = newcnt;
+
+	if (IS_ENABLED(CONFIG_TRACE_IRQFLAGS) && newcnt == cnt) {
+		raw_local_irq_save(flags);
+		lockdep_softirqs_off(ip);
+		raw_local_irq_restore(flags);
+	}
+}
+EXPORT_SYMBOL(__local_bh_disable_ip);
+
+static void __local_bh_enable(unsigned int cnt, bool unlock)
+{
+	unsigned long flags;
+	int newcnt;
+
+	DEBUG_LOCKS_WARN_ON(current->softirq_disable_cnt !=
+			    this_cpu_read(softirq_ctrl.cnt));
+
+	if (IS_ENABLED(CONFIG_TRACE_IRQFLAGS) && softirq_count() == cnt) {
+		raw_local_irq_save(flags);
+		lockdep_softirqs_on(_RET_IP_);
+		raw_local_irq_restore(flags);
+	}
+
+	newcnt = __this_cpu_sub_return(softirq_ctrl.cnt, cnt);
+	current->softirq_disable_cnt = newcnt;
+
+	if (!newcnt && unlock) {
+		rcu_read_unlock();
+		local_unlock(&softirq_ctrl.lock);
+	}
+}
+
+void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
+{
+	bool preempt_on = preemptible();
+	unsigned long flags;
+	u32 pending;
+	int curcnt;
+
+	WARN_ON_ONCE(in_hardirq());
+	lockdep_assert_irqs_enabled();
+
+	local_irq_save(flags);
+	curcnt = __this_cpu_read(softirq_ctrl.cnt);
+
+	/*
+	 * If this is not reenabling soft interrupts, no point in trying to
+	 * run pending ones.
+	 */
+	if (curcnt != cnt)
+		goto out;
+
+	pending = local_softirq_pending();
+	if (!pending || ksoftirqd_running(pending))
+		goto out;
+
+	/*
+	 * If this was called from non preemptible context, wake up the
+	 * softirq daemon.
+	 */
+	if (!preempt_on) {
+		wakeup_softirqd();
+		goto out;
+	}
+
+	/*
+	 * Adjust softirq count to SOFTIRQ_OFFSET which makes
+	 * in_serving_softirq() become true.
+	 */
+	cnt = SOFTIRQ_OFFSET;
+	__local_bh_enable(cnt, false);
+	__do_softirq();
+
+out:
+	__local_bh_enable(cnt, preempt_on);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(__local_bh_enable_ip);
+
+/*
+ * Invoked from ksoftirqd_run() outside of the interrupt disabled section
+ * to acquire the per CPU local lock for reentrancy protection.
+ */
+static inline void ksoftirqd_run_begin(void)
+{
+	__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
+	local_irq_disable();
+}
+
+/* Counterpart to ksoftirqd_run_begin() */
+static inline void ksoftirqd_run_end(void)
+{
+	__local_bh_enable(SOFTIRQ_OFFSET, true);
+	WARN_ON_ONCE(in_interrupt());
+	local_irq_enable();
+}
+
+static inline void softirq_handle_begin(void) { }
+static inline void softirq_handle_end(void) { }
+
+static inline bool should_wake_ksoftirqd(void)
+{
+	return !this_cpu_read(softirq_ctrl.cnt);
+}
+
+static inline void invoke_softirq(void)
+{
+	if (should_wake_ksoftirqd())
+		wakeup_softirqd();
+}
+
+/*
+ * flush_smp_call_function_queue() can raise a soft interrupt in a function
+ * call. On RT kernels this is undesired and the only known functionality
+ * in the block layer which does this is disabled on RT. If soft interrupts
+ * get raised which haven't been raised before the flush, warn so it can be
+ * investigated.
+ */
+void do_softirq_post_smp_call_flush(unsigned int was_pending)
+{
+	if (WARN_ON_ONCE(was_pending != local_softirq_pending()))
+		invoke_softirq();
+}
+
+#else /* CONFIG_PREEMPT_RT */
+
+/*
+ * This one is for softirq.c-internal use, where hardirqs are disabled
+ * legitimately:
+ */
+#ifdef CONFIG_TRACE_IRQFLAGS
+void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
+{
+	unsigned long flags;
+
+	WARN_ON_ONCE(in_hardirq());
+
+	raw_local_irq_save(flags);
+	/*
+	 * The preempt tracer hooks into preempt_count_add and will break
+	 * lockdep because it calls back into lockdep after SOFTIRQ_OFFSET
+	 * is set and before current->softirq_enabled is cleared.
+	 * We must manually increment preempt_count here and manually
+	 * call the trace_preempt_off later.
+	 */
+	__preempt_count_add(cnt);
+	/*
+	 * Were softirqs turned off above:
+	 */
+	if (softirq_count() == (cnt & SOFTIRQ_MASK))
+		lockdep_softirqs_off(ip);
+	raw_local_irq_restore(flags);
+
+	if (preempt_count() == cnt) {
+#ifdef CONFIG_DEBUG_PREEMPT
+		current->preempt_disable_ip = get_lock_parent_ip();
+#endif
+		trace_preempt_off(CALLER_ADDR0, get_lock_parent_ip());
+	}
+}
+EXPORT_SYMBOL(__local_bh_disable_ip);
+#endif /* CONFIG_TRACE_IRQFLAGS */
+
+static void __local_bh_enable(unsigned int cnt)
+{
+	lockdep_assert_irqs_disabled();
+
+	if (preempt_count() == cnt)
+		trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
+
+	if (softirq_count() == (cnt & SOFTIRQ_MASK))
+		lockdep_softirqs_on(_RET_IP_);
+
+	__preempt_count_sub(cnt);
+}
+
+/*
+ * Special-case - softirqs can safely be enabled by __do_softirq(),
+ * without processing still-pending softirqs:
+ */
+void _local_bh_enable(void)
+{
+	WARN_ON_ONCE(in_hardirq());
+	__local_bh_enable(SOFTIRQ_DISABLE_OFFSET);
+}
+EXPORT_SYMBOL(_local_bh_enable);
+
+void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
+{
+	WARN_ON_ONCE(in_hardirq());
+	lockdep_assert_irqs_enabled();
+#ifdef CONFIG_TRACE_IRQFLAGS
+	local_irq_disable();
+#endif
+	/*
+	 * Are softirqs going to be turned on now:
+	 */
+	if (softirq_count() == SOFTIRQ_DISABLE_OFFSET)
+		lockdep_softirqs_on(ip);
+	/*
+	 * Keep preemption disabled until we are done with
+	 * softirq processing:
+	 */
+	__preempt_count_sub(cnt - 1);
+
+	if (unlikely(!in_interrupt() && local_softirq_pending())) {
+		/*
+		 * Run softirq if any pending. And do it in its own stack
+		 * as we may be calling this deep in a task call stack already.
+		 */
+		do_softirq();
+	}
+
+	preempt_count_dec();
+#ifdef CONFIG_TRACE_IRQFLAGS
+	local_irq_enable();
+#endif
+	preempt_check_resched();
+}
+EXPORT_SYMBOL(__local_bh_enable_ip);
+
+static inline void softirq_handle_begin(void)
+{
+	__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
+}
+
+static inline void softirq_handle_end(void)
+{
+	__local_bh_enable(SOFTIRQ_OFFSET);
+	WARN_ON_ONCE(in_interrupt());
+}
+
+static inline void ksoftirqd_run_begin(void)
+{
+	local_irq_disable();
+}
+
+static inline void ksoftirqd_run_end(void)
+{
+	local_irq_enable();
+}
+
+static inline bool should_wake_ksoftirqd(void)
+{
+	return true;
+}
+
+static inline void invoke_softirq(void)
+{
+	if (ksoftirqd_running(local_softirq_pending()))
+		return;
+
+	if (!force_irqthreads() || !__this_cpu_read(ksoftirqd)) {
+#ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
+		/*
+		 * We can safely execute softirq on the current stack if
+		 * it is the irq stack, because it should be near empty
+		 * at this stage.
+		 */
+		__do_softirq();
+#else
+		/*
+		 * Otherwise, irq_exit() is called on the task stack that can
+		 * be potentially deep already. So call softirq in its own stack
+		 * to prevent from any overrun.
+		 */
+		do_softirq_own_stack();
+#endif
+	} else {
+		wakeup_softirqd();
+	}
+}
+
+asmlinkage __visible void do_softirq(void)
+{
+	__u32 pending;
+	unsigned long flags;
+
+	if (in_interrupt())
+		return;
+
+	local_irq_save(flags);
+
+	pending = local_softirq_pending();
+
+	if (pending && !ksoftirqd_running(pending))
+		do_softirq_own_stack();
+
+	local_irq_restore(flags);
+}
+
+#endif /* !CONFIG_PREEMPT_RT */
+
+/*
+ * We restart softirq processing for at most MAX_SOFTIRQ_RESTART times,
+ * but break the loop if need_resched() is set or after 2 ms.
+ * The MAX_SOFTIRQ_TIME provides a nice upper bound in most cases, but in
+ * certain cases, such as stop_machine(), jiffies may cease to
+ * increment and so we need the MAX_SOFTIRQ_RESTART limit as
+ * well to make sure we eventually return from this method.
+ *
+ * These limits have been established via experimentation.
+ * The two things to balance is latency against fairness -
+ * we want to handle softirqs as soon as possible, but they
+ * should not be able to lock up the box.
+ */
+#define MAX_SOFTIRQ_TIME  msecs_to_jiffies(2)
+#define MAX_SOFTIRQ_RESTART 10
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+/*
+ * When we run softirqs from irq_exit() and thus on the hardirq stack we need
+ * to keep the lockdep irq context tracking as tight as possible in order to
+ * not miss-qualify lock contexts and miss possible deadlocks.
+ */
+
+static inline bool lockdep_softirq_start(void)
+{
+	bool in_hardirq = false;
+
+	if (lockdep_hardirq_context()) {
+		in_hardirq = true;
+		lockdep_hardirq_exit();
+	}
+
+	lockdep_softirq_enter();
+
+	return in_hardirq;
+}
+
+static inline void lockdep_softirq_end(bool in_hardirq)
+{
+	lockdep_softirq_exit();
+
+	if (in_hardirq)
+		lockdep_hardirq_enter();
+}
+#else
+static inline bool lockdep_softirq_start(void) { return false; }
+static inline void lockdep_softirq_end(bool in_hardirq) { }
+#endif
+
+asmlinkage __visible void __softirq_entry __do_softirq(void)
+{
+	unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
+	unsigned long old_flags = current->flags;
+	int max_restart = MAX_SOFTIRQ_RESTART;
+	struct softirq_action *h;
+	bool in_hardirq;
+	__u32 pending;
+	int softirq_bit;
+
+	/*
+	 * Mask out PF_MEMALLOC as the current task context is borrowed for the
+	 * softirq. A softirq handled, such as network RX, might set PF_MEMALLOC
+	 * again if the socket is related to swapping.
+	 */
+	current->flags &= ~PF_MEMALLOC;
+
+	pending = local_softirq_pending();
+
+	softirq_handle_begin();
+	in_hardirq = lockdep_softirq_start();
+	account_softirq_enter(current);
+
+restart:
+	/* Reset the pending bitmask before enabling irqs */
+	set_softirq_pending(0);
+
+	local_irq_enable();
+
+	h = softirq_vec;
+
+	while ((softirq_bit = ffs(pending))) {
+		unsigned int vec_nr;
+		int prev_count;
+
+		h += softirq_bit - 1;
+
+		vec_nr = h - softirq_vec;
+		prev_count = preempt_count();
+
+		kstat_incr_softirqs_this_cpu(vec_nr);
+
+		trace_softirq_entry(vec_nr);
+		h->action(h);
+		trace_softirq_exit(vec_nr);
+		if (unlikely(prev_count != preempt_count())) {
+			pr_err("huh, entered softirq %u %s %p with preempt_count %08x, exited with %08x?\n",
+			       vec_nr, softirq_to_name[vec_nr], h->action,
+			       prev_count, preempt_count());
+			preempt_count_set(prev_count);
+		}
+		h++;
+		pending >>= softirq_bit;
+	}
+
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT) &&
+	    __this_cpu_read(ksoftirqd) == current)
+		rcu_softirq_qs();
+
+	local_irq_disable();
+
+	pending = local_softirq_pending();
+	if (pending) {
+		if (time_before(jiffies, end) && !need_resched() &&
+		    --max_restart)
+			goto restart;
+
+		wakeup_softirqd();
+	}
+
+	account_softirq_exit(current);
+	lockdep_softirq_end(in_hardirq);
+	softirq_handle_end();
+	current_restore_flags(old_flags, PF_MEMALLOC);
+}
+
+/**
+ * irq_enter_rcu - Enter an interrupt context with RCU watching
+ */
+void irq_enter_rcu(void)
+{
+	__irq_enter_raw();
+
+	if (tick_nohz_full_cpu(smp_processor_id()) ||
+	    (is_idle_task(current) && (irq_count() == HARDIRQ_OFFSET)))
+		tick_irq_enter();
+
+	account_hardirq_enter(current);
+}
+
+/**
+ * irq_enter - Enter an interrupt context including RCU update
+ */
+void irq_enter(void)
+{
+	ct_irq_enter();
+	irq_enter_rcu();
+}
+
+static inline void tick_irq_exit(void)
+{
+#ifdef CONFIG_NO_HZ_COMMON
+	int cpu = smp_processor_id();
+
+	/* Make sure that timer wheel updates are propagated */
+	if ((idle_cpu(cpu) && !need_resched()) || tick_nohz_full_cpu(cpu)) {
+		if (!in_hardirq())
+			tick_nohz_irq_exit();
+	}
+#endif
+}
+
+static inline void __irq_exit_rcu(void)
+{
+#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
+	local_irq_disable();
+#else
+	lockdep_assert_irqs_disabled();
+#endif
+	account_hardirq_exit(current);
+	preempt_count_sub(HARDIRQ_OFFSET);
+	if (!in_interrupt() && local_softirq_pending())
+		invoke_softirq();
+
+	tick_irq_exit();
+}
+
+/**
+ * irq_exit_rcu() - Exit an interrupt context without updating RCU
+ *
+ * Also processes softirqs if needed and possible.
+ */
+void irq_exit_rcu(void)
+{
+	__irq_exit_rcu();
+	 /* must be last! */
+	lockdep_hardirq_exit();
+}
+
+/**
+ * irq_exit - Exit an interrupt context, update RCU and lockdep
+ *
+ * Also processes softirqs if needed and possible.
+ */
+void irq_exit(void)
+{
+	__irq_exit_rcu();
+	ct_irq_exit();
+	 /* must be last! */
+	lockdep_hardirq_exit();
+}
+
+/*
+ * This function must run with irqs disabled!
+ */
+inline void raise_softirq_irqoff(unsigned int nr)
+{
+	__raise_softirq_irqoff(nr);
+
+	/*
+	 * If we're in an interrupt or softirq, we're done
+	 * (this also catches softirq-disabled code). We will
+	 * actually run the softirq once we return from
+	 * the irq or softirq.
+	 *
+	 * Otherwise we wake up ksoftirqd to make sure we
+	 * schedule the softirq soon.
+	 */
+	if (!in_interrupt() && should_wake_ksoftirqd())
+		wakeup_softirqd();
+}
+
+void raise_softirq(unsigned int nr)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	raise_softirq_irqoff(nr);
+	local_irq_restore(flags);
+}
+
+void __raise_softirq_irqoff(unsigned int nr)
+{
+	lockdep_assert_irqs_disabled();
+	trace_softirq_raise(nr);
+	or_softirq_pending(1UL << nr);
+}
+
+void open_softirq(int nr, void (*action)(struct softirq_action *))
+{
+	softirq_vec[nr].action = action;
+}
+
+/*
+ * Tasklets
+ */
+struct tasklet_head {
+	struct tasklet_struct *head;
+	struct tasklet_struct **tail;
+};
+
+static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec);
+static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec);
+
+static void __tasklet_schedule_common(struct tasklet_struct *t,
+				      struct tasklet_head __percpu *headp,
+				      unsigned int softirq_nr)
+{
+	struct tasklet_head *head;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	head = this_cpu_ptr(headp);
+	t->next = NULL;
+	*head->tail = t;
+	head->tail = &(t->next);
+	raise_softirq_irqoff(softirq_nr);
+	local_irq_restore(flags);
+}
+
+void __tasklet_schedule(struct tasklet_struct *t)
+{
+	__tasklet_schedule_common(t, &tasklet_vec,
+				  TASKLET_SOFTIRQ);
+}
+EXPORT_SYMBOL(__tasklet_schedule);
+
+void __tasklet_hi_schedule(struct tasklet_struct *t)
+{
+	__tasklet_schedule_common(t, &tasklet_hi_vec,
+				  HI_SOFTIRQ);
+}
+EXPORT_SYMBOL(__tasklet_hi_schedule);
+
+static bool tasklet_clear_sched(struct tasklet_struct *t)
+{
+	if (test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) {
+		wake_up_var(&t->state);
+		return true;
+	}
+
+	WARN_ONCE(1, "tasklet SCHED state not set: %s %pS\n",
+		  t->use_callback ? "callback" : "func",
+		  t->use_callback ? (void *)t->callback : (void *)t->func);
+
+	return false;
+}
+
+static void tasklet_action_common(struct softirq_action *a,
+				  struct tasklet_head *tl_head,
+				  unsigned int softirq_nr)
+{
+	struct tasklet_struct *list;
+
+	local_irq_disable();
+	list = tl_head->head;
+	tl_head->head = NULL;
+	tl_head->tail = &tl_head->head;
+	local_irq_enable();
+
+	while (list) {
+		struct tasklet_struct *t = list;
+
+		list = list->next;
+
+		if (tasklet_trylock(t)) {
+			if (!atomic_read(&t->count)) {
+				if (tasklet_clear_sched(t)) {
+					if (t->use_callback)
+						t->callback(t);
+					else
+						t->func(t->data);
+				}
+				tasklet_unlock(t);
+				continue;
+			}
+			tasklet_unlock(t);
+		}
+
+		local_irq_disable();
+		t->next = NULL;
+		*tl_head->tail = t;
+		tl_head->tail = &t->next;
+		__raise_softirq_irqoff(softirq_nr);
+		local_irq_enable();
+	}
+}
+
+static __latent_entropy void tasklet_action(struct softirq_action *a)
+{
+	tasklet_action_common(a, this_cpu_ptr(&tasklet_vec), TASKLET_SOFTIRQ);
+}
+
+static __latent_entropy void tasklet_hi_action(struct softirq_action *a)
+{
+	tasklet_action_common(a, this_cpu_ptr(&tasklet_hi_vec), HI_SOFTIRQ);
+}
+
+void tasklet_setup(struct tasklet_struct *t,
+		   void (*callback)(struct tasklet_struct *))
+{
+	t->next = NULL;
+	t->state = 0;
+	atomic_set(&t->count, 0);
+	t->callback = callback;
+	t->use_callback = true;
+	t->data = 0;
+}
+EXPORT_SYMBOL(tasklet_setup);
+
+void tasklet_init(struct tasklet_struct *t,
+		  void (*func)(unsigned long), unsigned long data)
+{
+	t->next = NULL;
+	t->state = 0;
+	atomic_set(&t->count, 0);
+	t->func = func;
+	t->use_callback = false;
+	t->data = data;
+}
+EXPORT_SYMBOL(tasklet_init);
+
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
+/*
+ * Do not use in new code. Waiting for tasklets from atomic contexts is
+ * error prone and should be avoided.
+ */
+void tasklet_unlock_spin_wait(struct tasklet_struct *t)
+{
+	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) {
+		if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+			/*
+			 * Prevent a live lock when current preempted soft
+			 * interrupt processing or prevents ksoftirqd from
+			 * running. If the tasklet runs on a different CPU
+			 * then this has no effect other than doing the BH
+			 * disable/enable dance for nothing.
+			 */
+			local_bh_disable();
+			local_bh_enable();
+		} else {
+			cpu_relax();
+		}
+	}
+}
+EXPORT_SYMBOL(tasklet_unlock_spin_wait);
+#endif
+
+void tasklet_kill(struct tasklet_struct *t)
+{
+	if (in_interrupt())
+		pr_notice("Attempt to kill tasklet from interrupt\n");
+
+	while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
+		wait_var_event(&t->state, !test_bit(TASKLET_STATE_SCHED, &t->state));
+
+	tasklet_unlock_wait(t);
+	tasklet_clear_sched(t);
+}
+EXPORT_SYMBOL(tasklet_kill);
+
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
+void tasklet_unlock(struct tasklet_struct *t)
+{
+	smp_mb__before_atomic();
+	clear_bit(TASKLET_STATE_RUN, &t->state);
+	smp_mb__after_atomic();
+	wake_up_var(&t->state);
+}
+EXPORT_SYMBOL_GPL(tasklet_unlock);
+
+void tasklet_unlock_wait(struct tasklet_struct *t)
+{
+	wait_var_event(&t->state, !test_bit(TASKLET_STATE_RUN, &t->state));
+}
+EXPORT_SYMBOL_GPL(tasklet_unlock_wait);
+#endif
+
+void __init softirq_init(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		per_cpu(tasklet_vec, cpu).tail =
+			&per_cpu(tasklet_vec, cpu).head;
+		per_cpu(tasklet_hi_vec, cpu).tail =
+			&per_cpu(tasklet_hi_vec, cpu).head;
+	}
+
+	open_softirq(TASKLET_SOFTIRQ, tasklet_action);
+	open_softirq(HI_SOFTIRQ, tasklet_hi_action);
+}
+
+static int ksoftirqd_should_run(unsigned int cpu)
+{
+	return local_softirq_pending();
+}
+
+static void run_ksoftirqd(unsigned int cpu)
+{
+	ksoftirqd_run_begin();
+	if (local_softirq_pending()) {
+		/*
+		 * We can safely run softirq on inline stack, as we are not deep
+		 * in the task stack here.
+		 */
+		__do_softirq();
+		ksoftirqd_run_end();
+		cond_resched();
+		return;
+	}
+	ksoftirqd_run_end();
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int takeover_tasklets(unsigned int cpu)
+{
+	/* CPU is dead, so no lock needed. */
+	local_irq_disable();
+
+	/* Find end, append list for that CPU. */
+	if (&per_cpu(tasklet_vec, cpu).head != per_cpu(tasklet_vec, cpu).tail) {
+		*__this_cpu_read(tasklet_vec.tail) = per_cpu(tasklet_vec, cpu).head;
+		__this_cpu_write(tasklet_vec.tail, per_cpu(tasklet_vec, cpu).tail);
+		per_cpu(tasklet_vec, cpu).head = NULL;
+		per_cpu(tasklet_vec, cpu).tail = &per_cpu(tasklet_vec, cpu).head;
+	}
+	raise_softirq_irqoff(TASKLET_SOFTIRQ);
+
+	if (&per_cpu(tasklet_hi_vec, cpu).head != per_cpu(tasklet_hi_vec, cpu).tail) {
+		*__this_cpu_read(tasklet_hi_vec.tail) = per_cpu(tasklet_hi_vec, cpu).head;
+		__this_cpu_write(tasklet_hi_vec.tail, per_cpu(tasklet_hi_vec, cpu).tail);
+		per_cpu(tasklet_hi_vec, cpu).head = NULL;
+		per_cpu(tasklet_hi_vec, cpu).tail = &per_cpu(tasklet_hi_vec, cpu).head;
+	}
+	raise_softirq_irqoff(HI_SOFTIRQ);
+
+	local_irq_enable();
+	return 0;
+}
+#else
+#define takeover_tasklets	NULL
+#endif /* CONFIG_HOTPLUG_CPU */
+
+static struct smp_hotplug_thread softirq_threads = {
+	.store			= &ksoftirqd,
+	.thread_should_run	= ksoftirqd_should_run,
+	.thread_fn		= run_ksoftirqd,
+	.thread_comm		= "ksoftirqd/%u",
+};
+
+static __init int spawn_ksoftirqd(void)
+{
+	cpuhp_setup_state_nocalls(CPUHP_SOFTIRQ_DEAD, "softirq:dead", NULL,
+				  takeover_tasklets);
+	BUG_ON(smpboot_register_percpu_thread(&softirq_threads));
+
+	return 0;
+}
+early_initcall(spawn_ksoftirqd);
+
+/*
+ * [ These __weak aliases are kept in a separate compilation unit, so that
+ *   GCC does not inline them incorrectly. ]
+ */
+
+int __init __weak early_irq_init(void)
+{
+	return 0;
+}
+
+int __init __weak arch_probe_nr_irqs(void)
+{
+	return NR_IRQS_LEGACY;
+}
+
+int __init __weak arch_early_irq_init(void)
+{
+	return 0;
+}
+
+unsigned int __weak arch_dynirq_lower_bound(unsigned int from)
+{
+	return from;
+}
diff --git a/kernel/stackleak.c b/kernel/stackleak.c
new file mode 100644
index 000000000..c2c33d220
--- /dev/null
+++ b/kernel/stackleak.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This code fills the used part of the kernel stack with a poison value
+ * before returning to userspace. It's part of the STACKLEAK feature
+ * ported from grsecurity/PaX.
+ *
+ * Author: Alexander Popov <alex.popov@linux.com>
+ *
+ * STACKLEAK reduces the information which kernel stack leak bugs can
+ * reveal and blocks some uninitialized stack variable attacks.
+ */
+
+#include <linux/stackleak.h>
+#include <linux/kprobes.h>
+
+#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE
+#include <linux/jump_label.h>
+#include <linux/sysctl.h>
+#include <linux/init.h>
+
+static DEFINE_STATIC_KEY_FALSE(stack_erasing_bypass);
+
+#ifdef CONFIG_SYSCTL
+static int stack_erasing_sysctl(struct ctl_table *table, int write,
+			void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	int ret = 0;
+	int state = !static_branch_unlikely(&stack_erasing_bypass);
+	int prev_state = state;
+
+	table->data = &state;
+	table->maxlen = sizeof(int);
+	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+	state = !!state;
+	if (ret || !write || state == prev_state)
+		return ret;
+
+	if (state)
+		static_branch_disable(&stack_erasing_bypass);
+	else
+		static_branch_enable(&stack_erasing_bypass);
+
+	pr_warn("stackleak: kernel stack erasing is %s\n",
+					state ? "enabled" : "disabled");
+	return ret;
+}
+static struct ctl_table stackleak_sysctls[] = {
+	{
+		.procname	= "stack_erasing",
+		.data		= NULL,
+		.maxlen		= sizeof(int),
+		.mode		= 0600,
+		.proc_handler	= stack_erasing_sysctl,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{}
+};
+
+static int __init stackleak_sysctls_init(void)
+{
+	register_sysctl_init("kernel", stackleak_sysctls);
+	return 0;
+}
+late_initcall(stackleak_sysctls_init);
+#endif /* CONFIG_SYSCTL */
+
+#define skip_erasing()	static_branch_unlikely(&stack_erasing_bypass)
+#else
+#define skip_erasing()	false
+#endif /* CONFIG_STACKLEAK_RUNTIME_DISABLE */
+
+static __always_inline void __stackleak_erase(bool on_task_stack)
+{
+	const unsigned long task_stack_low = stackleak_task_low_bound(current);
+	const unsigned long task_stack_high = stackleak_task_high_bound(current);
+	unsigned long erase_low, erase_high;
+
+	erase_low = stackleak_find_top_of_poison(task_stack_low,
+						 current->lowest_stack);
+
+#ifdef CONFIG_STACKLEAK_METRICS
+	current->prev_lowest_stack = erase_low;
+#endif
+
+	/*
+	 * Write poison to the task's stack between 'erase_low' and
+	 * 'erase_high'.
+	 *
+	 * If we're running on a different stack (e.g. an entry trampoline
+	 * stack) we can erase everything below the pt_regs at the top of the
+	 * task stack.
+	 *
+	 * If we're running on the task stack itself, we must not clobber any
+	 * stack used by this function and its caller. We assume that this
+	 * function has a fixed-size stack frame, and the current stack pointer
+	 * doesn't change while we write poison.
+	 */
+	if (on_task_stack)
+		erase_high = current_stack_pointer;
+	else
+		erase_high = task_stack_high;
+
+	while (erase_low < erase_high) {
+		*(unsigned long *)erase_low = STACKLEAK_POISON;
+		erase_low += sizeof(unsigned long);
+	}
+
+	/* Reset the 'lowest_stack' value for the next syscall */
+	current->lowest_stack = task_stack_high;
+}
+
+/*
+ * Erase and poison the portion of the task stack used since the last erase.
+ * Can be called from the task stack or an entry stack when the task stack is
+ * no longer in use.
+ */
+asmlinkage void noinstr stackleak_erase(void)
+{
+	if (skip_erasing())
+		return;
+
+	__stackleak_erase(on_thread_stack());
+}
+
+/*
+ * Erase and poison the portion of the task stack used since the last erase.
+ * Can only be called from the task stack.
+ */
+asmlinkage void noinstr stackleak_erase_on_task_stack(void)
+{
+	if (skip_erasing())
+		return;
+
+	__stackleak_erase(true);
+}
+
+/*
+ * Erase and poison the portion of the task stack used since the last erase.
+ * Can only be called from a stack other than the task stack.
+ */
+asmlinkage void noinstr stackleak_erase_off_task_stack(void)
+{
+	if (skip_erasing())
+		return;
+
+	__stackleak_erase(false);
+}
+
+void __used __no_caller_saved_registers noinstr stackleak_track_stack(void)
+{
+	unsigned long sp = current_stack_pointer;
+
+	/*
+	 * Having CONFIG_STACKLEAK_TRACK_MIN_SIZE larger than
+	 * STACKLEAK_SEARCH_DEPTH makes the poison search in
+	 * stackleak_erase() unreliable. Let's prevent that.
+	 */
+	BUILD_BUG_ON(CONFIG_STACKLEAK_TRACK_MIN_SIZE > STACKLEAK_SEARCH_DEPTH);
+
+	/* 'lowest_stack' should be aligned on the register width boundary */
+	sp = ALIGN(sp, sizeof(unsigned long));
+	if (sp < current->lowest_stack &&
+	    sp >= stackleak_task_low_bound(current)) {
+		current->lowest_stack = sp;
+	}
+}
+EXPORT_SYMBOL(stackleak_track_stack);
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
new file mode 100644
index 000000000..9ed5ce989
--- /dev/null
+++ b/kernel/stacktrace.c
@@ -0,0 +1,402 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/stacktrace.c
+ *
+ * Stack trace management functions
+ *
+ *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ */
+#include <linux/sched/task_stack.h>
+#include <linux/sched/debug.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/kallsyms.h>
+#include <linux/stacktrace.h>
+#include <linux/interrupt.h>
+
+/**
+ * stack_trace_print - Print the entries in the stack trace
+ * @entries:	Pointer to storage array
+ * @nr_entries:	Number of entries in the storage array
+ * @spaces:	Number of leading spaces to print
+ */
+void stack_trace_print(const unsigned long *entries, unsigned int nr_entries,
+		       int spaces)
+{
+	unsigned int i;
+
+	if (WARN_ON(!entries))
+		return;
+
+	for (i = 0; i < nr_entries; i++)
+		printk("%*c%pS\n", 1 + spaces, ' ', (void *)entries[i]);
+}
+EXPORT_SYMBOL_GPL(stack_trace_print);
+
+/**
+ * stack_trace_snprint - Print the entries in the stack trace into a buffer
+ * @buf:	Pointer to the print buffer
+ * @size:	Size of the print buffer
+ * @entries:	Pointer to storage array
+ * @nr_entries:	Number of entries in the storage array
+ * @spaces:	Number of leading spaces to print
+ *
+ * Return: Number of bytes printed.
+ */
+int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries,
+			unsigned int nr_entries, int spaces)
+{
+	unsigned int generated, i, total = 0;
+
+	if (WARN_ON(!entries))
+		return 0;
+
+	for (i = 0; i < nr_entries && size; i++) {
+		generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ',
+				     (void *)entries[i]);
+
+		total += generated;
+		if (generated >= size) {
+			buf += size;
+			size = 0;
+		} else {
+			buf += generated;
+			size -= generated;
+		}
+	}
+
+	return total;
+}
+EXPORT_SYMBOL_GPL(stack_trace_snprint);
+
+#ifdef CONFIG_ARCH_STACKWALK
+
+struct stacktrace_cookie {
+	unsigned long	*store;
+	unsigned int	size;
+	unsigned int	skip;
+	unsigned int	len;
+};
+
+static bool stack_trace_consume_entry(void *cookie, unsigned long addr)
+{
+	struct stacktrace_cookie *c = cookie;
+
+	if (c->len >= c->size)
+		return false;
+
+	if (c->skip > 0) {
+		c->skip--;
+		return true;
+	}
+	c->store[c->len++] = addr;
+	return c->len < c->size;
+}
+
+static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr)
+{
+	if (in_sched_functions(addr))
+		return true;
+	return stack_trace_consume_entry(cookie, addr);
+}
+
+/**
+ * stack_trace_save - Save a stack trace into a storage array
+ * @store:	Pointer to storage array
+ * @size:	Size of the storage array
+ * @skipnr:	Number of entries to skip at the start of the stack trace
+ *
+ * Return: Number of trace entries stored.
+ */
+unsigned int stack_trace_save(unsigned long *store, unsigned int size,
+			      unsigned int skipnr)
+{
+	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
+	struct stacktrace_cookie c = {
+		.store	= store,
+		.size	= size,
+		.skip	= skipnr + 1,
+	};
+
+	arch_stack_walk(consume_entry, &c, current, NULL);
+	return c.len;
+}
+EXPORT_SYMBOL_GPL(stack_trace_save);
+
+/**
+ * stack_trace_save_tsk - Save a task stack trace into a storage array
+ * @task:	The task to examine
+ * @store:	Pointer to storage array
+ * @size:	Size of the storage array
+ * @skipnr:	Number of entries to skip at the start of the stack trace
+ *
+ * Return: Number of trace entries stored.
+ */
+unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
+				  unsigned int size, unsigned int skipnr)
+{
+	stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched;
+	struct stacktrace_cookie c = {
+		.store	= store,
+		.size	= size,
+		/* skip this function if they are tracing us */
+		.skip	= skipnr + (current == tsk),
+	};
+
+	if (!try_get_task_stack(tsk))
+		return 0;
+
+	arch_stack_walk(consume_entry, &c, tsk, NULL);
+	put_task_stack(tsk);
+	return c.len;
+}
+
+/**
+ * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
+ * @regs:	Pointer to pt_regs to examine
+ * @store:	Pointer to storage array
+ * @size:	Size of the storage array
+ * @skipnr:	Number of entries to skip at the start of the stack trace
+ *
+ * Return: Number of trace entries stored.
+ */
+unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
+				   unsigned int size, unsigned int skipnr)
+{
+	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
+	struct stacktrace_cookie c = {
+		.store	= store,
+		.size	= size,
+		.skip	= skipnr,
+	};
+
+	arch_stack_walk(consume_entry, &c, current, regs);
+	return c.len;
+}
+
+#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
+/**
+ * stack_trace_save_tsk_reliable - Save task stack with verification
+ * @tsk:	Pointer to the task to examine
+ * @store:	Pointer to storage array
+ * @size:	Size of the storage array
+ *
+ * Return:	An error if it detects any unreliable features of the
+ *		stack. Otherwise it guarantees that the stack trace is
+ *		reliable and returns the number of entries stored.
+ *
+ * If the task is not 'current', the caller *must* ensure the task is inactive.
+ */
+int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
+				  unsigned int size)
+{
+	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
+	struct stacktrace_cookie c = {
+		.store	= store,
+		.size	= size,
+	};
+	int ret;
+
+	/*
+	 * If the task doesn't have a stack (e.g., a zombie), the stack is
+	 * "reliably" empty.
+	 */
+	if (!try_get_task_stack(tsk))
+		return 0;
+
+	ret = arch_stack_walk_reliable(consume_entry, &c, tsk);
+	put_task_stack(tsk);
+	return ret ? ret : c.len;
+}
+#endif
+
+#ifdef CONFIG_USER_STACKTRACE_SUPPORT
+/**
+ * stack_trace_save_user - Save a user space stack trace into a storage array
+ * @store:	Pointer to storage array
+ * @size:	Size of the storage array
+ *
+ * Return: Number of trace entries stored.
+ */
+unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
+{
+	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
+	struct stacktrace_cookie c = {
+		.store	= store,
+		.size	= size,
+	};
+
+	/* Trace user stack if not a kernel thread */
+	if (current->flags & PF_KTHREAD)
+		return 0;
+
+	arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
+
+	return c.len;
+}
+#endif
+
+#else /* CONFIG_ARCH_STACKWALK */
+
+/*
+ * Architectures that do not implement save_stack_trace_*()
+ * get these weak aliases and once-per-bootup warnings
+ * (whenever this facility is utilized - for example by procfs):
+ */
+__weak void
+save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+{
+	WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
+}
+
+__weak void
+save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
+{
+	WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
+}
+
+/**
+ * stack_trace_save - Save a stack trace into a storage array
+ * @store:	Pointer to storage array
+ * @size:	Size of the storage array
+ * @skipnr:	Number of entries to skip at the start of the stack trace
+ *
+ * Return: Number of trace entries stored
+ */
+unsigned int stack_trace_save(unsigned long *store, unsigned int size,
+			      unsigned int skipnr)
+{
+	struct stack_trace trace = {
+		.entries	= store,
+		.max_entries	= size,
+		.skip		= skipnr + 1,
+	};
+
+	save_stack_trace(&trace);
+	return trace.nr_entries;
+}
+EXPORT_SYMBOL_GPL(stack_trace_save);
+
+/**
+ * stack_trace_save_tsk - Save a task stack trace into a storage array
+ * @task:	The task to examine
+ * @store:	Pointer to storage array
+ * @size:	Size of the storage array
+ * @skipnr:	Number of entries to skip at the start of the stack trace
+ *
+ * Return: Number of trace entries stored
+ */
+unsigned int stack_trace_save_tsk(struct task_struct *task,
+				  unsigned long *store, unsigned int size,
+				  unsigned int skipnr)
+{
+	struct stack_trace trace = {
+		.entries	= store,
+		.max_entries	= size,
+		/* skip this function if they are tracing us */
+		.skip	= skipnr + (current == task),
+	};
+
+	save_stack_trace_tsk(task, &trace);
+	return trace.nr_entries;
+}
+
+/**
+ * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
+ * @regs:	Pointer to pt_regs to examine
+ * @store:	Pointer to storage array
+ * @size:	Size of the storage array
+ * @skipnr:	Number of entries to skip at the start of the stack trace
+ *
+ * Return: Number of trace entries stored
+ */
+unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
+				   unsigned int size, unsigned int skipnr)
+{
+	struct stack_trace trace = {
+		.entries	= store,
+		.max_entries	= size,
+		.skip		= skipnr,
+	};
+
+	save_stack_trace_regs(regs, &trace);
+	return trace.nr_entries;
+}
+
+#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
+/**
+ * stack_trace_save_tsk_reliable - Save task stack with verification
+ * @tsk:	Pointer to the task to examine
+ * @store:	Pointer to storage array
+ * @size:	Size of the storage array
+ *
+ * Return:	An error if it detects any unreliable features of the
+ *		stack. Otherwise it guarantees that the stack trace is
+ *		reliable and returns the number of entries stored.
+ *
+ * If the task is not 'current', the caller *must* ensure the task is inactive.
+ */
+int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
+				  unsigned int size)
+{
+	struct stack_trace trace = {
+		.entries	= store,
+		.max_entries	= size,
+	};
+	int ret = save_stack_trace_tsk_reliable(tsk, &trace);
+
+	return ret ? ret : trace.nr_entries;
+}
+#endif
+
+#ifdef CONFIG_USER_STACKTRACE_SUPPORT
+/**
+ * stack_trace_save_user - Save a user space stack trace into a storage array
+ * @store:	Pointer to storage array
+ * @size:	Size of the storage array
+ *
+ * Return: Number of trace entries stored
+ */
+unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
+{
+	struct stack_trace trace = {
+		.entries	= store,
+		.max_entries	= size,
+	};
+
+	save_stack_trace_user(&trace);
+	return trace.nr_entries;
+}
+#endif /* CONFIG_USER_STACKTRACE_SUPPORT */
+
+#endif /* !CONFIG_ARCH_STACKWALK */
+
+static inline bool in_irqentry_text(unsigned long ptr)
+{
+	return (ptr >= (unsigned long)&__irqentry_text_start &&
+		ptr < (unsigned long)&__irqentry_text_end) ||
+		(ptr >= (unsigned long)&__softirqentry_text_start &&
+		 ptr < (unsigned long)&__softirqentry_text_end);
+}
+
+/**
+ * filter_irq_stacks - Find first IRQ stack entry in trace
+ * @entries:	Pointer to stack trace array
+ * @nr_entries:	Number of entries in the storage array
+ *
+ * Return: Number of trace entries until IRQ stack starts.
+ */
+unsigned int filter_irq_stacks(unsigned long *entries, unsigned int nr_entries)
+{
+	unsigned int i;
+
+	for (i = 0; i < nr_entries; i++) {
+		if (in_irqentry_text(entries[i])) {
+			/* Include the irqentry function into the stack. */
+			return i + 1;
+		}
+	}
+	return nr_entries;
+}
+EXPORT_SYMBOL_GPL(filter_irq_stacks);
diff --git a/kernel/static_call.c b/kernel/static_call.c
new file mode 100644
index 000000000..e9c3e69f3
--- /dev/null
+++ b/kernel/static_call.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/static_call.h>
+
+long __static_call_return0(void)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__static_call_return0);
diff --git a/kernel/static_call_inline.c b/kernel/static_call_inline.c
new file mode 100644
index 000000000..dc5665b62
--- /dev/null
+++ b/kernel/static_call_inline.c
@@ -0,0 +1,543 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/init.h>
+#include <linux/static_call.h>
+#include <linux/bug.h>
+#include <linux/smp.h>
+#include <linux/sort.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/cpu.h>
+#include <linux/processor.h>
+#include <asm/sections.h>
+
+extern struct static_call_site __start_static_call_sites[],
+			       __stop_static_call_sites[];
+extern struct static_call_tramp_key __start_static_call_tramp_key[],
+				    __stop_static_call_tramp_key[];
+
+static bool static_call_initialized;
+
+/* mutex to protect key modules/sites */
+static DEFINE_MUTEX(static_call_mutex);
+
+static void static_call_lock(void)
+{
+	mutex_lock(&static_call_mutex);
+}
+
+static void static_call_unlock(void)
+{
+	mutex_unlock(&static_call_mutex);
+}
+
+static inline void *static_call_addr(struct static_call_site *site)
+{
+	return (void *)((long)site->addr + (long)&site->addr);
+}
+
+static inline unsigned long __static_call_key(const struct static_call_site *site)
+{
+	return (long)site->key + (long)&site->key;
+}
+
+static inline struct static_call_key *static_call_key(const struct static_call_site *site)
+{
+	return (void *)(__static_call_key(site) & ~STATIC_CALL_SITE_FLAGS);
+}
+
+/* These assume the key is word-aligned. */
+static inline bool static_call_is_init(struct static_call_site *site)
+{
+	return __static_call_key(site) & STATIC_CALL_SITE_INIT;
+}
+
+static inline bool static_call_is_tail(struct static_call_site *site)
+{
+	return __static_call_key(site) & STATIC_CALL_SITE_TAIL;
+}
+
+static inline void static_call_set_init(struct static_call_site *site)
+{
+	site->key = (__static_call_key(site) | STATIC_CALL_SITE_INIT) -
+		    (long)&site->key;
+}
+
+static int static_call_site_cmp(const void *_a, const void *_b)
+{
+	const struct static_call_site *a = _a;
+	const struct static_call_site *b = _b;
+	const struct static_call_key *key_a = static_call_key(a);
+	const struct static_call_key *key_b = static_call_key(b);
+
+	if (key_a < key_b)
+		return -1;
+
+	if (key_a > key_b)
+		return 1;
+
+	return 0;
+}
+
+static void static_call_site_swap(void *_a, void *_b, int size)
+{
+	long delta = (unsigned long)_a - (unsigned long)_b;
+	struct static_call_site *a = _a;
+	struct static_call_site *b = _b;
+	struct static_call_site tmp = *a;
+
+	a->addr = b->addr  - delta;
+	a->key  = b->key   - delta;
+
+	b->addr = tmp.addr + delta;
+	b->key  = tmp.key  + delta;
+}
+
+static inline void static_call_sort_entries(struct static_call_site *start,
+					    struct static_call_site *stop)
+{
+	sort(start, stop - start, sizeof(struct static_call_site),
+	     static_call_site_cmp, static_call_site_swap);
+}
+
+static inline bool static_call_key_has_mods(struct static_call_key *key)
+{
+	return !(key->type & 1);
+}
+
+static inline struct static_call_mod *static_call_key_next(struct static_call_key *key)
+{
+	if (!static_call_key_has_mods(key))
+		return NULL;
+
+	return key->mods;
+}
+
+static inline struct static_call_site *static_call_key_sites(struct static_call_key *key)
+{
+	if (static_call_key_has_mods(key))
+		return NULL;
+
+	return (struct static_call_site *)(key->type & ~1);
+}
+
+void __static_call_update(struct static_call_key *key, void *tramp, void *func)
+{
+	struct static_call_site *site, *stop;
+	struct static_call_mod *site_mod, first;
+
+	cpus_read_lock();
+	static_call_lock();
+
+	if (key->func == func)
+		goto done;
+
+	key->func = func;
+
+	arch_static_call_transform(NULL, tramp, func, false);
+
+	/*
+	 * If uninitialized, we'll not update the callsites, but they still
+	 * point to the trampoline and we just patched that.
+	 */
+	if (WARN_ON_ONCE(!static_call_initialized))
+		goto done;
+
+	first = (struct static_call_mod){
+		.next = static_call_key_next(key),
+		.mod = NULL,
+		.sites = static_call_key_sites(key),
+	};
+
+	for (site_mod = &first; site_mod; site_mod = site_mod->next) {
+		bool init = system_state < SYSTEM_RUNNING;
+		struct module *mod = site_mod->mod;
+
+		if (!site_mod->sites) {
+			/*
+			 * This can happen if the static call key is defined in
+			 * a module which doesn't use it.
+			 *
+			 * It also happens in the has_mods case, where the
+			 * 'first' entry has no sites associated with it.
+			 */
+			continue;
+		}
+
+		stop = __stop_static_call_sites;
+
+		if (mod) {
+#ifdef CONFIG_MODULES
+			stop = mod->static_call_sites +
+			       mod->num_static_call_sites;
+			init = mod->state == MODULE_STATE_COMING;
+#endif
+		}
+
+		for (site = site_mod->sites;
+		     site < stop && static_call_key(site) == key; site++) {
+			void *site_addr = static_call_addr(site);
+
+			if (!init && static_call_is_init(site))
+				continue;
+
+			if (!kernel_text_address((unsigned long)site_addr)) {
+				/*
+				 * This skips patching built-in __exit, which
+				 * is part of init_section_contains() but is
+				 * not part of kernel_text_address().
+				 *
+				 * Skipping built-in __exit is fine since it
+				 * will never be executed.
+				 */
+				WARN_ONCE(!static_call_is_init(site),
+					  "can't patch static call site at %pS",
+					  site_addr);
+				continue;
+			}
+
+			arch_static_call_transform(site_addr, NULL, func,
+						   static_call_is_tail(site));
+		}
+	}
+
+done:
+	static_call_unlock();
+	cpus_read_unlock();
+}
+EXPORT_SYMBOL_GPL(__static_call_update);
+
+static int __static_call_init(struct module *mod,
+			      struct static_call_site *start,
+			      struct static_call_site *stop)
+{
+	struct static_call_site *site;
+	struct static_call_key *key, *prev_key = NULL;
+	struct static_call_mod *site_mod;
+
+	if (start == stop)
+		return 0;
+
+	static_call_sort_entries(start, stop);
+
+	for (site = start; site < stop; site++) {
+		void *site_addr = static_call_addr(site);
+
+		if ((mod && within_module_init((unsigned long)site_addr, mod)) ||
+		    (!mod && init_section_contains(site_addr, 1)))
+			static_call_set_init(site);
+
+		key = static_call_key(site);
+		if (key != prev_key) {
+			prev_key = key;
+
+			/*
+			 * For vmlinux (!mod) avoid the allocation by storing
+			 * the sites pointer in the key itself. Also see
+			 * __static_call_update()'s @first.
+			 *
+			 * This allows architectures (eg. x86) to call
+			 * static_call_init() before memory allocation works.
+			 */
+			if (!mod) {
+				key->sites = site;
+				key->type |= 1;
+				goto do_transform;
+			}
+
+			site_mod = kzalloc(sizeof(*site_mod), GFP_KERNEL);
+			if (!site_mod)
+				return -ENOMEM;
+
+			/*
+			 * When the key has a direct sites pointer, extract
+			 * that into an explicit struct static_call_mod, so we
+			 * can have a list of modules.
+			 */
+			if (static_call_key_sites(key)) {
+				site_mod->mod = NULL;
+				site_mod->next = NULL;
+				site_mod->sites = static_call_key_sites(key);
+
+				key->mods = site_mod;
+
+				site_mod = kzalloc(sizeof(*site_mod), GFP_KERNEL);
+				if (!site_mod)
+					return -ENOMEM;
+			}
+
+			site_mod->mod = mod;
+			site_mod->sites = site;
+			site_mod->next = static_call_key_next(key);
+			key->mods = site_mod;
+		}
+
+do_transform:
+		arch_static_call_transform(site_addr, NULL, key->func,
+				static_call_is_tail(site));
+	}
+
+	return 0;
+}
+
+static int addr_conflict(struct static_call_site *site, void *start, void *end)
+{
+	unsigned long addr = (unsigned long)static_call_addr(site);
+
+	if (addr <= (unsigned long)end &&
+	    addr + CALL_INSN_SIZE > (unsigned long)start)
+		return 1;
+
+	return 0;
+}
+
+static int __static_call_text_reserved(struct static_call_site *iter_start,
+				       struct static_call_site *iter_stop,
+				       void *start, void *end, bool init)
+{
+	struct static_call_site *iter = iter_start;
+
+	while (iter < iter_stop) {
+		if (init || !static_call_is_init(iter)) {
+			if (addr_conflict(iter, start, end))
+				return 1;
+		}
+		iter++;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_MODULES
+
+static int __static_call_mod_text_reserved(void *start, void *end)
+{
+	struct module *mod;
+	int ret;
+
+	preempt_disable();
+	mod = __module_text_address((unsigned long)start);
+	WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
+	if (!try_module_get(mod))
+		mod = NULL;
+	preempt_enable();
+
+	if (!mod)
+		return 0;
+
+	ret = __static_call_text_reserved(mod->static_call_sites,
+			mod->static_call_sites + mod->num_static_call_sites,
+			start, end, mod->state == MODULE_STATE_COMING);
+
+	module_put(mod);
+
+	return ret;
+}
+
+static unsigned long tramp_key_lookup(unsigned long addr)
+{
+	struct static_call_tramp_key *start = __start_static_call_tramp_key;
+	struct static_call_tramp_key *stop = __stop_static_call_tramp_key;
+	struct static_call_tramp_key *tramp_key;
+
+	for (tramp_key = start; tramp_key != stop; tramp_key++) {
+		unsigned long tramp;
+
+		tramp = (long)tramp_key->tramp + (long)&tramp_key->tramp;
+		if (tramp == addr)
+			return (long)tramp_key->key + (long)&tramp_key->key;
+	}
+
+	return 0;
+}
+
+static int static_call_add_module(struct module *mod)
+{
+	struct static_call_site *start = mod->static_call_sites;
+	struct static_call_site *stop = start + mod->num_static_call_sites;
+	struct static_call_site *site;
+
+	for (site = start; site != stop; site++) {
+		unsigned long s_key = __static_call_key(site);
+		unsigned long addr = s_key & ~STATIC_CALL_SITE_FLAGS;
+		unsigned long key;
+
+		/*
+		 * Is the key is exported, 'addr' points to the key, which
+		 * means modules are allowed to call static_call_update() on
+		 * it.
+		 *
+		 * Otherwise, the key isn't exported, and 'addr' points to the
+		 * trampoline so we need to lookup the key.
+		 *
+		 * We go through this dance to prevent crazy modules from
+		 * abusing sensitive static calls.
+		 */
+		if (!kernel_text_address(addr))
+			continue;
+
+		key = tramp_key_lookup(addr);
+		if (!key) {
+			pr_warn("Failed to fixup __raw_static_call() usage at: %ps\n",
+				static_call_addr(site));
+			return -EINVAL;
+		}
+
+		key |= s_key & STATIC_CALL_SITE_FLAGS;
+		site->key = key - (long)&site->key;
+	}
+
+	return __static_call_init(mod, start, stop);
+}
+
+static void static_call_del_module(struct module *mod)
+{
+	struct static_call_site *start = mod->static_call_sites;
+	struct static_call_site *stop = mod->static_call_sites +
+					mod->num_static_call_sites;
+	struct static_call_key *key, *prev_key = NULL;
+	struct static_call_mod *site_mod, **prev;
+	struct static_call_site *site;
+
+	for (site = start; site < stop; site++) {
+		key = static_call_key(site);
+		if (key == prev_key)
+			continue;
+
+		prev_key = key;
+
+		for (prev = &key->mods, site_mod = key->mods;
+		     site_mod && site_mod->mod != mod;
+		     prev = &site_mod->next, site_mod = site_mod->next)
+			;
+
+		if (!site_mod)
+			continue;
+
+		*prev = site_mod->next;
+		kfree(site_mod);
+	}
+}
+
+static int static_call_module_notify(struct notifier_block *nb,
+				     unsigned long val, void *data)
+{
+	struct module *mod = data;
+	int ret = 0;
+
+	cpus_read_lock();
+	static_call_lock();
+
+	switch (val) {
+	case MODULE_STATE_COMING:
+		ret = static_call_add_module(mod);
+		if (ret) {
+			WARN(1, "Failed to allocate memory for static calls");
+			static_call_del_module(mod);
+		}
+		break;
+	case MODULE_STATE_GOING:
+		static_call_del_module(mod);
+		break;
+	}
+
+	static_call_unlock();
+	cpus_read_unlock();
+
+	return notifier_from_errno(ret);
+}
+
+static struct notifier_block static_call_module_nb = {
+	.notifier_call = static_call_module_notify,
+};
+
+#else
+
+static inline int __static_call_mod_text_reserved(void *start, void *end)
+{
+	return 0;
+}
+
+#endif /* CONFIG_MODULES */
+
+int static_call_text_reserved(void *start, void *end)
+{
+	bool init = system_state < SYSTEM_RUNNING;
+	int ret = __static_call_text_reserved(__start_static_call_sites,
+			__stop_static_call_sites, start, end, init);
+
+	if (ret)
+		return ret;
+
+	return __static_call_mod_text_reserved(start, end);
+}
+
+int __init static_call_init(void)
+{
+	int ret;
+
+	if (static_call_initialized)
+		return 0;
+
+	cpus_read_lock();
+	static_call_lock();
+	ret = __static_call_init(NULL, __start_static_call_sites,
+				 __stop_static_call_sites);
+	static_call_unlock();
+	cpus_read_unlock();
+
+	if (ret) {
+		pr_err("Failed to allocate memory for static_call!\n");
+		BUG();
+	}
+
+	static_call_initialized = true;
+
+#ifdef CONFIG_MODULES
+	register_module_notifier(&static_call_module_nb);
+#endif
+	return 0;
+}
+early_initcall(static_call_init);
+
+#ifdef CONFIG_STATIC_CALL_SELFTEST
+
+static int func_a(int x)
+{
+	return x+1;
+}
+
+static int func_b(int x)
+{
+	return x+2;
+}
+
+DEFINE_STATIC_CALL(sc_selftest, func_a);
+
+static struct static_call_data {
+      int (*func)(int);
+      int val;
+      int expect;
+} static_call_data [] __initdata = {
+      { NULL,   2, 3 },
+      { func_b, 2, 4 },
+      { func_a, 2, 3 }
+};
+
+static int __init test_static_call_init(void)
+{
+      int i;
+
+      for (i = 0; i < ARRAY_SIZE(static_call_data); i++ ) {
+	      struct static_call_data *scd = &static_call_data[i];
+
+              if (scd->func)
+                      static_call_update(sc_selftest, scd->func);
+
+              WARN_ON(static_call(sc_selftest)(scd->val) != scd->expect);
+      }
+
+      return 0;
+}
+early_initcall(test_static_call_init);
+
+#endif /* CONFIG_STATIC_CALL_SELFTEST */
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
new file mode 100644
index 000000000..cedb17ba1
--- /dev/null
+++ b/kernel/stop_machine.c
@@ -0,0 +1,706 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * kernel/stop_machine.c
+ *
+ * Copyright (C) 2008, 2005	IBM Corporation.
+ * Copyright (C) 2008, 2005	Rusty Russell rusty@rustcorp.com.au
+ * Copyright (C) 2010		SUSE Linux Products GmbH
+ * Copyright (C) 2010		Tejun Heo <tj@kernel.org>
+ */
+#include <linux/compiler.h>
+#include <linux/completion.h>
+#include <linux/cpu.h>
+#include <linux/init.h>
+#include <linux/kthread.h>
+#include <linux/export.h>
+#include <linux/percpu.h>
+#include <linux/sched.h>
+#include <linux/stop_machine.h>
+#include <linux/interrupt.h>
+#include <linux/kallsyms.h>
+#include <linux/smpboot.h>
+#include <linux/atomic.h>
+#include <linux/nmi.h>
+#include <linux/sched/wake_q.h>
+
+/*
+ * Structure to determine completion condition and record errors.  May
+ * be shared by works on different cpus.
+ */
+struct cpu_stop_done {
+	atomic_t		nr_todo;	/* nr left to execute */
+	int			ret;		/* collected return value */
+	struct completion	completion;	/* fired if nr_todo reaches 0 */
+};
+
+/* the actual stopper, one per every possible cpu, enabled on online cpus */
+struct cpu_stopper {
+	struct task_struct	*thread;
+
+	raw_spinlock_t		lock;
+	bool			enabled;	/* is this stopper enabled? */
+	struct list_head	works;		/* list of pending works */
+
+	struct cpu_stop_work	stop_work;	/* for stop_cpus */
+	unsigned long		caller;
+	cpu_stop_fn_t		fn;
+};
+
+static DEFINE_PER_CPU(struct cpu_stopper, cpu_stopper);
+static bool stop_machine_initialized = false;
+
+void print_stop_info(const char *log_lvl, struct task_struct *task)
+{
+	/*
+	 * If @task is a stopper task, it cannot migrate and task_cpu() is
+	 * stable.
+	 */
+	struct cpu_stopper *stopper = per_cpu_ptr(&cpu_stopper, task_cpu(task));
+
+	if (task != stopper->thread)
+		return;
+
+	printk("%sStopper: %pS <- %pS\n", log_lvl, stopper->fn, (void *)stopper->caller);
+}
+
+/* static data for stop_cpus */
+static DEFINE_MUTEX(stop_cpus_mutex);
+static bool stop_cpus_in_progress;
+
+static void cpu_stop_init_done(struct cpu_stop_done *done, unsigned int nr_todo)
+{
+	memset(done, 0, sizeof(*done));
+	atomic_set(&done->nr_todo, nr_todo);
+	init_completion(&done->completion);
+}
+
+/* signal completion unless @done is NULL */
+static void cpu_stop_signal_done(struct cpu_stop_done *done)
+{
+	if (atomic_dec_and_test(&done->nr_todo))
+		complete(&done->completion);
+}
+
+static void __cpu_stop_queue_work(struct cpu_stopper *stopper,
+					struct cpu_stop_work *work,
+					struct wake_q_head *wakeq)
+{
+	list_add_tail(&work->list, &stopper->works);
+	wake_q_add(wakeq, stopper->thread);
+}
+
+/* queue @work to @stopper.  if offline, @work is completed immediately */
+static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)
+{
+	struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
+	DEFINE_WAKE_Q(wakeq);
+	unsigned long flags;
+	bool enabled;
+
+	preempt_disable();
+	raw_spin_lock_irqsave(&stopper->lock, flags);
+	enabled = stopper->enabled;
+	if (enabled)
+		__cpu_stop_queue_work(stopper, work, &wakeq);
+	else if (work->done)
+		cpu_stop_signal_done(work->done);
+	raw_spin_unlock_irqrestore(&stopper->lock, flags);
+
+	wake_up_q(&wakeq);
+	preempt_enable();
+
+	return enabled;
+}
+
+/**
+ * stop_one_cpu - stop a cpu
+ * @cpu: cpu to stop
+ * @fn: function to execute
+ * @arg: argument to @fn
+ *
+ * Execute @fn(@arg) on @cpu.  @fn is run in a process context with
+ * the highest priority preempting any task on the cpu and
+ * monopolizing it.  This function returns after the execution is
+ * complete.
+ *
+ * This function doesn't guarantee @cpu stays online till @fn
+ * completes.  If @cpu goes down in the middle, execution may happen
+ * partially or fully on different cpus.  @fn should either be ready
+ * for that or the caller should ensure that @cpu stays online until
+ * this function completes.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * -ENOENT if @fn(@arg) was not executed because @cpu was offline;
+ * otherwise, the return value of @fn.
+ */
+int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg)
+{
+	struct cpu_stop_done done;
+	struct cpu_stop_work work = { .fn = fn, .arg = arg, .done = &done, .caller = _RET_IP_ };
+
+	cpu_stop_init_done(&done, 1);
+	if (!cpu_stop_queue_work(cpu, &work))
+		return -ENOENT;
+	/*
+	 * In case @cpu == smp_proccessor_id() we can avoid a sleep+wakeup
+	 * cycle by doing a preemption:
+	 */
+	cond_resched();
+	wait_for_completion(&done.completion);
+	return done.ret;
+}
+
+/* This controls the threads on each CPU. */
+enum multi_stop_state {
+	/* Dummy starting state for thread. */
+	MULTI_STOP_NONE,
+	/* Awaiting everyone to be scheduled. */
+	MULTI_STOP_PREPARE,
+	/* Disable interrupts. */
+	MULTI_STOP_DISABLE_IRQ,
+	/* Run the function */
+	MULTI_STOP_RUN,
+	/* Exit */
+	MULTI_STOP_EXIT,
+};
+
+struct multi_stop_data {
+	cpu_stop_fn_t		fn;
+	void			*data;
+	/* Like num_online_cpus(), but hotplug cpu uses us, so we need this. */
+	unsigned int		num_threads;
+	const struct cpumask	*active_cpus;
+
+	enum multi_stop_state	state;
+	atomic_t		thread_ack;
+};
+
+static void set_state(struct multi_stop_data *msdata,
+		      enum multi_stop_state newstate)
+{
+	/* Reset ack counter. */
+	atomic_set(&msdata->thread_ack, msdata->num_threads);
+	smp_wmb();
+	WRITE_ONCE(msdata->state, newstate);
+}
+
+/* Last one to ack a state moves to the next state. */
+static void ack_state(struct multi_stop_data *msdata)
+{
+	if (atomic_dec_and_test(&msdata->thread_ack))
+		set_state(msdata, msdata->state + 1);
+}
+
+notrace void __weak stop_machine_yield(const struct cpumask *cpumask)
+{
+	cpu_relax();
+}
+
+/* This is the cpu_stop function which stops the CPU. */
+static int multi_cpu_stop(void *data)
+{
+	struct multi_stop_data *msdata = data;
+	enum multi_stop_state newstate, curstate = MULTI_STOP_NONE;
+	int cpu = smp_processor_id(), err = 0;
+	const struct cpumask *cpumask;
+	unsigned long flags;
+	bool is_active;
+
+	/*
+	 * When called from stop_machine_from_inactive_cpu(), irq might
+	 * already be disabled.  Save the state and restore it on exit.
+	 */
+	local_save_flags(flags);
+
+	if (!msdata->active_cpus) {
+		cpumask = cpu_online_mask;
+		is_active = cpu == cpumask_first(cpumask);
+	} else {
+		cpumask = msdata->active_cpus;
+		is_active = cpumask_test_cpu(cpu, cpumask);
+	}
+
+	/* Simple state machine */
+	do {
+		/* Chill out and ensure we re-read multi_stop_state. */
+		stop_machine_yield(cpumask);
+		newstate = READ_ONCE(msdata->state);
+		if (newstate != curstate) {
+			curstate = newstate;
+			switch (curstate) {
+			case MULTI_STOP_DISABLE_IRQ:
+				local_irq_disable();
+				hard_irq_disable();
+				break;
+			case MULTI_STOP_RUN:
+				if (is_active)
+					err = msdata->fn(msdata->data);
+				break;
+			default:
+				break;
+			}
+			ack_state(msdata);
+		} else if (curstate > MULTI_STOP_PREPARE) {
+			/*
+			 * At this stage all other CPUs we depend on must spin
+			 * in the same loop. Any reason for hard-lockup should
+			 * be detected and reported on their side.
+			 */
+			touch_nmi_watchdog();
+		}
+		rcu_momentary_dyntick_idle();
+	} while (curstate != MULTI_STOP_EXIT);
+
+	local_irq_restore(flags);
+	return err;
+}
+
+static int cpu_stop_queue_two_works(int cpu1, struct cpu_stop_work *work1,
+				    int cpu2, struct cpu_stop_work *work2)
+{
+	struct cpu_stopper *stopper1 = per_cpu_ptr(&cpu_stopper, cpu1);
+	struct cpu_stopper *stopper2 = per_cpu_ptr(&cpu_stopper, cpu2);
+	DEFINE_WAKE_Q(wakeq);
+	int err;
+
+retry:
+	/*
+	 * The waking up of stopper threads has to happen in the same
+	 * scheduling context as the queueing.  Otherwise, there is a
+	 * possibility of one of the above stoppers being woken up by another
+	 * CPU, and preempting us. This will cause us to not wake up the other
+	 * stopper forever.
+	 */
+	preempt_disable();
+	raw_spin_lock_irq(&stopper1->lock);
+	raw_spin_lock_nested(&stopper2->lock, SINGLE_DEPTH_NESTING);
+
+	if (!stopper1->enabled || !stopper2->enabled) {
+		err = -ENOENT;
+		goto unlock;
+	}
+
+	/*
+	 * Ensure that if we race with __stop_cpus() the stoppers won't get
+	 * queued up in reverse order leading to system deadlock.
+	 *
+	 * We can't miss stop_cpus_in_progress if queue_stop_cpus_work() has
+	 * queued a work on cpu1 but not on cpu2, we hold both locks.
+	 *
+	 * It can be falsely true but it is safe to spin until it is cleared,
+	 * queue_stop_cpus_work() does everything under preempt_disable().
+	 */
+	if (unlikely(stop_cpus_in_progress)) {
+		err = -EDEADLK;
+		goto unlock;
+	}
+
+	err = 0;
+	__cpu_stop_queue_work(stopper1, work1, &wakeq);
+	__cpu_stop_queue_work(stopper2, work2, &wakeq);
+
+unlock:
+	raw_spin_unlock(&stopper2->lock);
+	raw_spin_unlock_irq(&stopper1->lock);
+
+	if (unlikely(err == -EDEADLK)) {
+		preempt_enable();
+
+		while (stop_cpus_in_progress)
+			cpu_relax();
+
+		goto retry;
+	}
+
+	wake_up_q(&wakeq);
+	preempt_enable();
+
+	return err;
+}
+/**
+ * stop_two_cpus - stops two cpus
+ * @cpu1: the cpu to stop
+ * @cpu2: the other cpu to stop
+ * @fn: function to execute
+ * @arg: argument to @fn
+ *
+ * Stops both the current and specified CPU and runs @fn on one of them.
+ *
+ * returns when both are completed.
+ */
+int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void *arg)
+{
+	struct cpu_stop_done done;
+	struct cpu_stop_work work1, work2;
+	struct multi_stop_data msdata;
+
+	msdata = (struct multi_stop_data){
+		.fn = fn,
+		.data = arg,
+		.num_threads = 2,
+		.active_cpus = cpumask_of(cpu1),
+	};
+
+	work1 = work2 = (struct cpu_stop_work){
+		.fn = multi_cpu_stop,
+		.arg = &msdata,
+		.done = &done,
+		.caller = _RET_IP_,
+	};
+
+	cpu_stop_init_done(&done, 2);
+	set_state(&msdata, MULTI_STOP_PREPARE);
+
+	if (cpu1 > cpu2)
+		swap(cpu1, cpu2);
+	if (cpu_stop_queue_two_works(cpu1, &work1, cpu2, &work2))
+		return -ENOENT;
+
+	wait_for_completion(&done.completion);
+	return done.ret;
+}
+
+/**
+ * stop_one_cpu_nowait - stop a cpu but don't wait for completion
+ * @cpu: cpu to stop
+ * @fn: function to execute
+ * @arg: argument to @fn
+ * @work_buf: pointer to cpu_stop_work structure
+ *
+ * Similar to stop_one_cpu() but doesn't wait for completion.  The
+ * caller is responsible for ensuring @work_buf is currently unused
+ * and will remain untouched until stopper starts executing @fn.
+ *
+ * CONTEXT:
+ * Don't care.
+ *
+ * RETURNS:
+ * true if cpu_stop_work was queued successfully and @fn will be called,
+ * false otherwise.
+ */
+bool stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,
+			struct cpu_stop_work *work_buf)
+{
+	*work_buf = (struct cpu_stop_work){ .fn = fn, .arg = arg, .caller = _RET_IP_, };
+	return cpu_stop_queue_work(cpu, work_buf);
+}
+
+static bool queue_stop_cpus_work(const struct cpumask *cpumask,
+				 cpu_stop_fn_t fn, void *arg,
+				 struct cpu_stop_done *done)
+{
+	struct cpu_stop_work *work;
+	unsigned int cpu;
+	bool queued = false;
+
+	/*
+	 * Disable preemption while queueing to avoid getting
+	 * preempted by a stopper which might wait for other stoppers
+	 * to enter @fn which can lead to deadlock.
+	 */
+	preempt_disable();
+	stop_cpus_in_progress = true;
+	barrier();
+	for_each_cpu(cpu, cpumask) {
+		work = &per_cpu(cpu_stopper.stop_work, cpu);
+		work->fn = fn;
+		work->arg = arg;
+		work->done = done;
+		work->caller = _RET_IP_;
+		if (cpu_stop_queue_work(cpu, work))
+			queued = true;
+	}
+	barrier();
+	stop_cpus_in_progress = false;
+	preempt_enable();
+
+	return queued;
+}
+
+static int __stop_cpus(const struct cpumask *cpumask,
+		       cpu_stop_fn_t fn, void *arg)
+{
+	struct cpu_stop_done done;
+
+	cpu_stop_init_done(&done, cpumask_weight(cpumask));
+	if (!queue_stop_cpus_work(cpumask, fn, arg, &done))
+		return -ENOENT;
+	wait_for_completion(&done.completion);
+	return done.ret;
+}
+
+/**
+ * stop_cpus - stop multiple cpus
+ * @cpumask: cpus to stop
+ * @fn: function to execute
+ * @arg: argument to @fn
+ *
+ * Execute @fn(@arg) on online cpus in @cpumask.  On each target cpu,
+ * @fn is run in a process context with the highest priority
+ * preempting any task on the cpu and monopolizing it.  This function
+ * returns after all executions are complete.
+ *
+ * This function doesn't guarantee the cpus in @cpumask stay online
+ * till @fn completes.  If some cpus go down in the middle, execution
+ * on the cpu may happen partially or fully on different cpus.  @fn
+ * should either be ready for that or the caller should ensure that
+ * the cpus stay online until this function completes.
+ *
+ * All stop_cpus() calls are serialized making it safe for @fn to wait
+ * for all cpus to start executing it.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * -ENOENT if @fn(@arg) was not executed at all because all cpus in
+ * @cpumask were offline; otherwise, 0 if all executions of @fn
+ * returned 0, any non zero return value if any returned non zero.
+ */
+static int stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg)
+{
+	int ret;
+
+	/* static works are used, process one request at a time */
+	mutex_lock(&stop_cpus_mutex);
+	ret = __stop_cpus(cpumask, fn, arg);
+	mutex_unlock(&stop_cpus_mutex);
+	return ret;
+}
+
+static int cpu_stop_should_run(unsigned int cpu)
+{
+	struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
+	unsigned long flags;
+	int run;
+
+	raw_spin_lock_irqsave(&stopper->lock, flags);
+	run = !list_empty(&stopper->works);
+	raw_spin_unlock_irqrestore(&stopper->lock, flags);
+	return run;
+}
+
+static void cpu_stopper_thread(unsigned int cpu)
+{
+	struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
+	struct cpu_stop_work *work;
+
+repeat:
+	work = NULL;
+	raw_spin_lock_irq(&stopper->lock);
+	if (!list_empty(&stopper->works)) {
+		work = list_first_entry(&stopper->works,
+					struct cpu_stop_work, list);
+		list_del_init(&work->list);
+	}
+	raw_spin_unlock_irq(&stopper->lock);
+
+	if (work) {
+		cpu_stop_fn_t fn = work->fn;
+		void *arg = work->arg;
+		struct cpu_stop_done *done = work->done;
+		int ret;
+
+		/* cpu stop callbacks must not sleep, make in_atomic() == T */
+		stopper->caller = work->caller;
+		stopper->fn = fn;
+		preempt_count_inc();
+		ret = fn(arg);
+		if (done) {
+			if (ret)
+				done->ret = ret;
+			cpu_stop_signal_done(done);
+		}
+		preempt_count_dec();
+		stopper->fn = NULL;
+		stopper->caller = 0;
+		WARN_ONCE(preempt_count(),
+			  "cpu_stop: %ps(%p) leaked preempt count\n", fn, arg);
+		goto repeat;
+	}
+}
+
+void stop_machine_park(int cpu)
+{
+	struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
+	/*
+	 * Lockless. cpu_stopper_thread() will take stopper->lock and flush
+	 * the pending works before it parks, until then it is fine to queue
+	 * the new works.
+	 */
+	stopper->enabled = false;
+	kthread_park(stopper->thread);
+}
+
+static void cpu_stop_create(unsigned int cpu)
+{
+	sched_set_stop_task(cpu, per_cpu(cpu_stopper.thread, cpu));
+}
+
+static void cpu_stop_park(unsigned int cpu)
+{
+	struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
+
+	WARN_ON(!list_empty(&stopper->works));
+}
+
+void stop_machine_unpark(int cpu)
+{
+	struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
+
+	stopper->enabled = true;
+	kthread_unpark(stopper->thread);
+}
+
+static struct smp_hotplug_thread cpu_stop_threads = {
+	.store			= &cpu_stopper.thread,
+	.thread_should_run	= cpu_stop_should_run,
+	.thread_fn		= cpu_stopper_thread,
+	.thread_comm		= "migration/%u",
+	.create			= cpu_stop_create,
+	.park			= cpu_stop_park,
+	.selfparking		= true,
+};
+
+static int __init cpu_stop_init(void)
+{
+	unsigned int cpu;
+
+	for_each_possible_cpu(cpu) {
+		struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
+
+		raw_spin_lock_init(&stopper->lock);
+		INIT_LIST_HEAD(&stopper->works);
+	}
+
+	BUG_ON(smpboot_register_percpu_thread(&cpu_stop_threads));
+	stop_machine_unpark(raw_smp_processor_id());
+	stop_machine_initialized = true;
+	return 0;
+}
+early_initcall(cpu_stop_init);
+
+int stop_machine_cpuslocked(cpu_stop_fn_t fn, void *data,
+			    const struct cpumask *cpus)
+{
+	struct multi_stop_data msdata = {
+		.fn = fn,
+		.data = data,
+		.num_threads = num_online_cpus(),
+		.active_cpus = cpus,
+	};
+
+	lockdep_assert_cpus_held();
+
+	if (!stop_machine_initialized) {
+		/*
+		 * Handle the case where stop_machine() is called
+		 * early in boot before stop_machine() has been
+		 * initialized.
+		 */
+		unsigned long flags;
+		int ret;
+
+		WARN_ON_ONCE(msdata.num_threads != 1);
+
+		local_irq_save(flags);
+		hard_irq_disable();
+		ret = (*fn)(data);
+		local_irq_restore(flags);
+
+		return ret;
+	}
+
+	/* Set the initial state and stop all online cpus. */
+	set_state(&msdata, MULTI_STOP_PREPARE);
+	return stop_cpus(cpu_online_mask, multi_cpu_stop, &msdata);
+}
+
+int stop_machine(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus)
+{
+	int ret;
+
+	/* No CPUs can come up or down during this. */
+	cpus_read_lock();
+	ret = stop_machine_cpuslocked(fn, data, cpus);
+	cpus_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(stop_machine);
+
+#ifdef CONFIG_SCHED_SMT
+int stop_core_cpuslocked(unsigned int cpu, cpu_stop_fn_t fn, void *data)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+
+	struct multi_stop_data msdata = {
+		.fn = fn,
+		.data = data,
+		.num_threads = cpumask_weight(smt_mask),
+		.active_cpus = smt_mask,
+	};
+
+	lockdep_assert_cpus_held();
+
+	/* Set the initial state and stop all online cpus. */
+	set_state(&msdata, MULTI_STOP_PREPARE);
+	return stop_cpus(smt_mask, multi_cpu_stop, &msdata);
+}
+EXPORT_SYMBOL_GPL(stop_core_cpuslocked);
+#endif
+
+/**
+ * stop_machine_from_inactive_cpu - stop_machine() from inactive CPU
+ * @fn: the function to run
+ * @data: the data ptr for the @fn()
+ * @cpus: the cpus to run the @fn() on (NULL = any online cpu)
+ *
+ * This is identical to stop_machine() but can be called from a CPU which
+ * is not active.  The local CPU is in the process of hotplug (so no other
+ * CPU hotplug can start) and not marked active and doesn't have enough
+ * context to sleep.
+ *
+ * This function provides stop_machine() functionality for such state by
+ * using busy-wait for synchronization and executing @fn directly for local
+ * CPU.
+ *
+ * CONTEXT:
+ * Local CPU is inactive.  Temporarily stops all active CPUs.
+ *
+ * RETURNS:
+ * 0 if all executions of @fn returned 0, any non zero return value if any
+ * returned non zero.
+ */
+int stop_machine_from_inactive_cpu(cpu_stop_fn_t fn, void *data,
+				  const struct cpumask *cpus)
+{
+	struct multi_stop_data msdata = { .fn = fn, .data = data,
+					    .active_cpus = cpus };
+	struct cpu_stop_done done;
+	int ret;
+
+	/* Local CPU must be inactive and CPU hotplug in progress. */
+	BUG_ON(cpu_active(raw_smp_processor_id()));
+	msdata.num_threads = num_active_cpus() + 1;	/* +1 for local */
+
+	/* No proper task established and can't sleep - busy wait for lock. */
+	while (!mutex_trylock(&stop_cpus_mutex))
+		cpu_relax();
+
+	/* Schedule work on other CPUs and execute directly for local CPU */
+	set_state(&msdata, MULTI_STOP_PREPARE);
+	cpu_stop_init_done(&done, num_active_cpus());
+	queue_stop_cpus_work(cpu_active_mask, multi_cpu_stop, &msdata,
+			     &done);
+	ret = multi_cpu_stop(&msdata);
+
+	/* Busy wait for completion. */
+	while (!completion_done(&done.completion))
+		cpu_relax();
+
+	mutex_unlock(&stop_cpus_mutex);
+	return ret ?: done.ret;
+}
diff --git a/kernel/sys.c b/kernel/sys.c
new file mode 100644
index 000000000..c85e1abf7
--- /dev/null
+++ b/kernel/sys.c
@@ -0,0 +1,2806 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/kernel/sys.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/mm_inline.h>
+#include <linux/utsname.h>
+#include <linux/mman.h>
+#include <linux/reboot.h>
+#include <linux/prctl.h>
+#include <linux/highuid.h>
+#include <linux/fs.h>
+#include <linux/kmod.h>
+#include <linux/perf_event.h>
+#include <linux/resource.h>
+#include <linux/kernel.h>
+#include <linux/workqueue.h>
+#include <linux/capability.h>
+#include <linux/device.h>
+#include <linux/key.h>
+#include <linux/times.h>
+#include <linux/posix-timers.h>
+#include <linux/security.h>
+#include <linux/random.h>
+#include <linux/suspend.h>
+#include <linux/tty.h>
+#include <linux/signal.h>
+#include <linux/cn_proc.h>
+#include <linux/getcpu.h>
+#include <linux/task_io_accounting_ops.h>
+#include <linux/seccomp.h>
+#include <linux/cpu.h>
+#include <linux/personality.h>
+#include <linux/ptrace.h>
+#include <linux/fs_struct.h>
+#include <linux/file.h>
+#include <linux/mount.h>
+#include <linux/gfp.h>
+#include <linux/syscore_ops.h>
+#include <linux/version.h>
+#include <linux/ctype.h>
+#include <linux/syscall_user_dispatch.h>
+
+#include <linux/compat.h>
+#include <linux/syscalls.h>
+#include <linux/kprobes.h>
+#include <linux/user_namespace.h>
+#include <linux/time_namespace.h>
+#include <linux/binfmts.h>
+
+#include <linux/sched.h>
+#include <linux/sched/autogroup.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/stat.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/coredump.h>
+#include <linux/sched/task.h>
+#include <linux/sched/cputime.h>
+#include <linux/rcupdate.h>
+#include <linux/uidgid.h>
+#include <linux/cred.h>
+
+#include <linux/nospec.h>
+
+#include <linux/kmsg_dump.h>
+/* Move somewhere else to avoid recompiling? */
+#include <generated/utsrelease.h>
+
+#include <linux/uaccess.h>
+#include <asm/io.h>
+#include <asm/unistd.h>
+
+#include "uid16.h"
+
+#ifndef SET_UNALIGN_CTL
+# define SET_UNALIGN_CTL(a, b)	(-EINVAL)
+#endif
+#ifndef GET_UNALIGN_CTL
+# define GET_UNALIGN_CTL(a, b)	(-EINVAL)
+#endif
+#ifndef SET_FPEMU_CTL
+# define SET_FPEMU_CTL(a, b)	(-EINVAL)
+#endif
+#ifndef GET_FPEMU_CTL
+# define GET_FPEMU_CTL(a, b)	(-EINVAL)
+#endif
+#ifndef SET_FPEXC_CTL
+# define SET_FPEXC_CTL(a, b)	(-EINVAL)
+#endif
+#ifndef GET_FPEXC_CTL
+# define GET_FPEXC_CTL(a, b)	(-EINVAL)
+#endif
+#ifndef GET_ENDIAN
+# define GET_ENDIAN(a, b)	(-EINVAL)
+#endif
+#ifndef SET_ENDIAN
+# define SET_ENDIAN(a, b)	(-EINVAL)
+#endif
+#ifndef GET_TSC_CTL
+# define GET_TSC_CTL(a)		(-EINVAL)
+#endif
+#ifndef SET_TSC_CTL
+# define SET_TSC_CTL(a)		(-EINVAL)
+#endif
+#ifndef GET_FP_MODE
+# define GET_FP_MODE(a)		(-EINVAL)
+#endif
+#ifndef SET_FP_MODE
+# define SET_FP_MODE(a,b)	(-EINVAL)
+#endif
+#ifndef SVE_SET_VL
+# define SVE_SET_VL(a)		(-EINVAL)
+#endif
+#ifndef SVE_GET_VL
+# define SVE_GET_VL()		(-EINVAL)
+#endif
+#ifndef SME_SET_VL
+# define SME_SET_VL(a)		(-EINVAL)
+#endif
+#ifndef SME_GET_VL
+# define SME_GET_VL()		(-EINVAL)
+#endif
+#ifndef PAC_RESET_KEYS
+# define PAC_RESET_KEYS(a, b)	(-EINVAL)
+#endif
+#ifndef PAC_SET_ENABLED_KEYS
+# define PAC_SET_ENABLED_KEYS(a, b, c)	(-EINVAL)
+#endif
+#ifndef PAC_GET_ENABLED_KEYS
+# define PAC_GET_ENABLED_KEYS(a)	(-EINVAL)
+#endif
+#ifndef SET_TAGGED_ADDR_CTRL
+# define SET_TAGGED_ADDR_CTRL(a)	(-EINVAL)
+#endif
+#ifndef GET_TAGGED_ADDR_CTRL
+# define GET_TAGGED_ADDR_CTRL()		(-EINVAL)
+#endif
+
+/*
+ * this is where the system-wide overflow UID and GID are defined, for
+ * architectures that now have 32-bit UID/GID but didn't in the past
+ */
+
+int overflowuid = DEFAULT_OVERFLOWUID;
+int overflowgid = DEFAULT_OVERFLOWGID;
+
+EXPORT_SYMBOL(overflowuid);
+EXPORT_SYMBOL(overflowgid);
+
+/*
+ * the same as above, but for filesystems which can only store a 16-bit
+ * UID and GID. as such, this is needed on all architectures
+ */
+
+int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
+int fs_overflowgid = DEFAULT_FS_OVERFLOWGID;
+
+EXPORT_SYMBOL(fs_overflowuid);
+EXPORT_SYMBOL(fs_overflowgid);
+
+/*
+ * Returns true if current's euid is same as p's uid or euid,
+ * or has CAP_SYS_NICE to p's user_ns.
+ *
+ * Called with rcu_read_lock, creds are safe
+ */
+static bool set_one_prio_perm(struct task_struct *p)
+{
+	const struct cred *cred = current_cred(), *pcred = __task_cred(p);
+
+	if (uid_eq(pcred->uid,  cred->euid) ||
+	    uid_eq(pcred->euid, cred->euid))
+		return true;
+	if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
+		return true;
+	return false;
+}
+
+/*
+ * set the priority of a task
+ * - the caller must hold the RCU read lock
+ */
+static int set_one_prio(struct task_struct *p, int niceval, int error)
+{
+	int no_nice;
+
+	if (!set_one_prio_perm(p)) {
+		error = -EPERM;
+		goto out;
+	}
+	if (niceval < task_nice(p) && !can_nice(p, niceval)) {
+		error = -EACCES;
+		goto out;
+	}
+	no_nice = security_task_setnice(p, niceval);
+	if (no_nice) {
+		error = no_nice;
+		goto out;
+	}
+	if (error == -ESRCH)
+		error = 0;
+	set_user_nice(p, niceval);
+out:
+	return error;
+}
+
+SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
+{
+	struct task_struct *g, *p;
+	struct user_struct *user;
+	const struct cred *cred = current_cred();
+	int error = -EINVAL;
+	struct pid *pgrp;
+	kuid_t uid;
+
+	if (which > PRIO_USER || which < PRIO_PROCESS)
+		goto out;
+
+	/* normalize: avoid signed division (rounding problems) */
+	error = -ESRCH;
+	if (niceval < MIN_NICE)
+		niceval = MIN_NICE;
+	if (niceval > MAX_NICE)
+		niceval = MAX_NICE;
+
+	rcu_read_lock();
+	switch (which) {
+	case PRIO_PROCESS:
+		if (who)
+			p = find_task_by_vpid(who);
+		else
+			p = current;
+		if (p)
+			error = set_one_prio(p, niceval, error);
+		break;
+	case PRIO_PGRP:
+		if (who)
+			pgrp = find_vpid(who);
+		else
+			pgrp = task_pgrp(current);
+		read_lock(&tasklist_lock);
+		do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
+			error = set_one_prio(p, niceval, error);
+		} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
+		read_unlock(&tasklist_lock);
+		break;
+	case PRIO_USER:
+		uid = make_kuid(cred->user_ns, who);
+		user = cred->user;
+		if (!who)
+			uid = cred->uid;
+		else if (!uid_eq(uid, cred->uid)) {
+			user = find_user(uid);
+			if (!user)
+				goto out_unlock;	/* No processes for this user */
+		}
+		for_each_process_thread(g, p) {
+			if (uid_eq(task_uid(p), uid) && task_pid_vnr(p))
+				error = set_one_prio(p, niceval, error);
+		}
+		if (!uid_eq(uid, cred->uid))
+			free_uid(user);		/* For find_user() */
+		break;
+	}
+out_unlock:
+	rcu_read_unlock();
+out:
+	return error;
+}
+
+/*
+ * Ugh. To avoid negative return values, "getpriority()" will
+ * not return the normal nice-value, but a negated value that
+ * has been offset by 20 (ie it returns 40..1 instead of -20..19)
+ * to stay compatible.
+ */
+SYSCALL_DEFINE2(getpriority, int, which, int, who)
+{
+	struct task_struct *g, *p;
+	struct user_struct *user;
+	const struct cred *cred = current_cred();
+	long niceval, retval = -ESRCH;
+	struct pid *pgrp;
+	kuid_t uid;
+
+	if (which > PRIO_USER || which < PRIO_PROCESS)
+		return -EINVAL;
+
+	rcu_read_lock();
+	switch (which) {
+	case PRIO_PROCESS:
+		if (who)
+			p = find_task_by_vpid(who);
+		else
+			p = current;
+		if (p) {
+			niceval = nice_to_rlimit(task_nice(p));
+			if (niceval > retval)
+				retval = niceval;
+		}
+		break;
+	case PRIO_PGRP:
+		if (who)
+			pgrp = find_vpid(who);
+		else
+			pgrp = task_pgrp(current);
+		read_lock(&tasklist_lock);
+		do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
+			niceval = nice_to_rlimit(task_nice(p));
+			if (niceval > retval)
+				retval = niceval;
+		} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
+		read_unlock(&tasklist_lock);
+		break;
+	case PRIO_USER:
+		uid = make_kuid(cred->user_ns, who);
+		user = cred->user;
+		if (!who)
+			uid = cred->uid;
+		else if (!uid_eq(uid, cred->uid)) {
+			user = find_user(uid);
+			if (!user)
+				goto out_unlock;	/* No processes for this user */
+		}
+		for_each_process_thread(g, p) {
+			if (uid_eq(task_uid(p), uid) && task_pid_vnr(p)) {
+				niceval = nice_to_rlimit(task_nice(p));
+				if (niceval > retval)
+					retval = niceval;
+			}
+		}
+		if (!uid_eq(uid, cred->uid))
+			free_uid(user);		/* for find_user() */
+		break;
+	}
+out_unlock:
+	rcu_read_unlock();
+
+	return retval;
+}
+
+/*
+ * Unprivileged users may change the real gid to the effective gid
+ * or vice versa.  (BSD-style)
+ *
+ * If you set the real gid at all, or set the effective gid to a value not
+ * equal to the real gid, then the saved gid is set to the new effective gid.
+ *
+ * This makes it possible for a setgid program to completely drop its
+ * privileges, which is often a useful assertion to make when you are doing
+ * a security audit over a program.
+ *
+ * The general idea is that a program which uses just setregid() will be
+ * 100% compatible with BSD.  A program which uses just setgid() will be
+ * 100% compatible with POSIX with saved IDs.
+ *
+ * SMP: There are not races, the GIDs are checked only by filesystem
+ *      operations (as far as semantic preservation is concerned).
+ */
+#ifdef CONFIG_MULTIUSER
+long __sys_setregid(gid_t rgid, gid_t egid)
+{
+	struct user_namespace *ns = current_user_ns();
+	const struct cred *old;
+	struct cred *new;
+	int retval;
+	kgid_t krgid, kegid;
+
+	krgid = make_kgid(ns, rgid);
+	kegid = make_kgid(ns, egid);
+
+	if ((rgid != (gid_t) -1) && !gid_valid(krgid))
+		return -EINVAL;
+	if ((egid != (gid_t) -1) && !gid_valid(kegid))
+		return -EINVAL;
+
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+	old = current_cred();
+
+	retval = -EPERM;
+	if (rgid != (gid_t) -1) {
+		if (gid_eq(old->gid, krgid) ||
+		    gid_eq(old->egid, krgid) ||
+		    ns_capable_setid(old->user_ns, CAP_SETGID))
+			new->gid = krgid;
+		else
+			goto error;
+	}
+	if (egid != (gid_t) -1) {
+		if (gid_eq(old->gid, kegid) ||
+		    gid_eq(old->egid, kegid) ||
+		    gid_eq(old->sgid, kegid) ||
+		    ns_capable_setid(old->user_ns, CAP_SETGID))
+			new->egid = kegid;
+		else
+			goto error;
+	}
+
+	if (rgid != (gid_t) -1 ||
+	    (egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
+		new->sgid = new->egid;
+	new->fsgid = new->egid;
+
+	retval = security_task_fix_setgid(new, old, LSM_SETID_RE);
+	if (retval < 0)
+		goto error;
+
+	return commit_creds(new);
+
+error:
+	abort_creds(new);
+	return retval;
+}
+
+SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
+{
+	return __sys_setregid(rgid, egid);
+}
+
+/*
+ * setgid() is implemented like SysV w/ SAVED_IDS
+ *
+ * SMP: Same implicit races as above.
+ */
+long __sys_setgid(gid_t gid)
+{
+	struct user_namespace *ns = current_user_ns();
+	const struct cred *old;
+	struct cred *new;
+	int retval;
+	kgid_t kgid;
+
+	kgid = make_kgid(ns, gid);
+	if (!gid_valid(kgid))
+		return -EINVAL;
+
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+	old = current_cred();
+
+	retval = -EPERM;
+	if (ns_capable_setid(old->user_ns, CAP_SETGID))
+		new->gid = new->egid = new->sgid = new->fsgid = kgid;
+	else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
+		new->egid = new->fsgid = kgid;
+	else
+		goto error;
+
+	retval = security_task_fix_setgid(new, old, LSM_SETID_ID);
+	if (retval < 0)
+		goto error;
+
+	return commit_creds(new);
+
+error:
+	abort_creds(new);
+	return retval;
+}
+
+SYSCALL_DEFINE1(setgid, gid_t, gid)
+{
+	return __sys_setgid(gid);
+}
+
+/*
+ * change the user struct in a credentials set to match the new UID
+ */
+static int set_user(struct cred *new)
+{
+	struct user_struct *new_user;
+
+	new_user = alloc_uid(new->uid);
+	if (!new_user)
+		return -EAGAIN;
+
+	free_uid(new->user);
+	new->user = new_user;
+	return 0;
+}
+
+static void flag_nproc_exceeded(struct cred *new)
+{
+	if (new->ucounts == current_ucounts())
+		return;
+
+	/*
+	 * We don't fail in case of NPROC limit excess here because too many
+	 * poorly written programs don't check set*uid() return code, assuming
+	 * it never fails if called by root.  We may still enforce NPROC limit
+	 * for programs doing set*uid()+execve() by harmlessly deferring the
+	 * failure to the execve() stage.
+	 */
+	if (is_rlimit_overlimit(new->ucounts, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC)) &&
+			new->user != INIT_USER)
+		current->flags |= PF_NPROC_EXCEEDED;
+	else
+		current->flags &= ~PF_NPROC_EXCEEDED;
+}
+
+/*
+ * Unprivileged users may change the real uid to the effective uid
+ * or vice versa.  (BSD-style)
+ *
+ * If you set the real uid at all, or set the effective uid to a value not
+ * equal to the real uid, then the saved uid is set to the new effective uid.
+ *
+ * This makes it possible for a setuid program to completely drop its
+ * privileges, which is often a useful assertion to make when you are doing
+ * a security audit over a program.
+ *
+ * The general idea is that a program which uses just setreuid() will be
+ * 100% compatible with BSD.  A program which uses just setuid() will be
+ * 100% compatible with POSIX with saved IDs.
+ */
+long __sys_setreuid(uid_t ruid, uid_t euid)
+{
+	struct user_namespace *ns = current_user_ns();
+	const struct cred *old;
+	struct cred *new;
+	int retval;
+	kuid_t kruid, keuid;
+
+	kruid = make_kuid(ns, ruid);
+	keuid = make_kuid(ns, euid);
+
+	if ((ruid != (uid_t) -1) && !uid_valid(kruid))
+		return -EINVAL;
+	if ((euid != (uid_t) -1) && !uid_valid(keuid))
+		return -EINVAL;
+
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+	old = current_cred();
+
+	retval = -EPERM;
+	if (ruid != (uid_t) -1) {
+		new->uid = kruid;
+		if (!uid_eq(old->uid, kruid) &&
+		    !uid_eq(old->euid, kruid) &&
+		    !ns_capable_setid(old->user_ns, CAP_SETUID))
+			goto error;
+	}
+
+	if (euid != (uid_t) -1) {
+		new->euid = keuid;
+		if (!uid_eq(old->uid, keuid) &&
+		    !uid_eq(old->euid, keuid) &&
+		    !uid_eq(old->suid, keuid) &&
+		    !ns_capable_setid(old->user_ns, CAP_SETUID))
+			goto error;
+	}
+
+	if (!uid_eq(new->uid, old->uid)) {
+		retval = set_user(new);
+		if (retval < 0)
+			goto error;
+	}
+	if (ruid != (uid_t) -1 ||
+	    (euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
+		new->suid = new->euid;
+	new->fsuid = new->euid;
+
+	retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
+	if (retval < 0)
+		goto error;
+
+	retval = set_cred_ucounts(new);
+	if (retval < 0)
+		goto error;
+
+	flag_nproc_exceeded(new);
+	return commit_creds(new);
+
+error:
+	abort_creds(new);
+	return retval;
+}
+
+SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
+{
+	return __sys_setreuid(ruid, euid);
+}
+
+/*
+ * setuid() is implemented like SysV with SAVED_IDS
+ *
+ * Note that SAVED_ID's is deficient in that a setuid root program
+ * like sendmail, for example, cannot set its uid to be a normal
+ * user and then switch back, because if you're root, setuid() sets
+ * the saved uid too.  If you don't like this, blame the bright people
+ * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
+ * will allow a root program to temporarily drop privileges and be able to
+ * regain them by swapping the real and effective uid.
+ */
+long __sys_setuid(uid_t uid)
+{
+	struct user_namespace *ns = current_user_ns();
+	const struct cred *old;
+	struct cred *new;
+	int retval;
+	kuid_t kuid;
+
+	kuid = make_kuid(ns, uid);
+	if (!uid_valid(kuid))
+		return -EINVAL;
+
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+	old = current_cred();
+
+	retval = -EPERM;
+	if (ns_capable_setid(old->user_ns, CAP_SETUID)) {
+		new->suid = new->uid = kuid;
+		if (!uid_eq(kuid, old->uid)) {
+			retval = set_user(new);
+			if (retval < 0)
+				goto error;
+		}
+	} else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
+		goto error;
+	}
+
+	new->fsuid = new->euid = kuid;
+
+	retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
+	if (retval < 0)
+		goto error;
+
+	retval = set_cred_ucounts(new);
+	if (retval < 0)
+		goto error;
+
+	flag_nproc_exceeded(new);
+	return commit_creds(new);
+
+error:
+	abort_creds(new);
+	return retval;
+}
+
+SYSCALL_DEFINE1(setuid, uid_t, uid)
+{
+	return __sys_setuid(uid);
+}
+
+
+/*
+ * This function implements a generic ability to update ruid, euid,
+ * and suid.  This allows you to implement the 4.4 compatible seteuid().
+ */
+long __sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
+{
+	struct user_namespace *ns = current_user_ns();
+	const struct cred *old;
+	struct cred *new;
+	int retval;
+	kuid_t kruid, keuid, ksuid;
+	bool ruid_new, euid_new, suid_new;
+
+	kruid = make_kuid(ns, ruid);
+	keuid = make_kuid(ns, euid);
+	ksuid = make_kuid(ns, suid);
+
+	if ((ruid != (uid_t) -1) && !uid_valid(kruid))
+		return -EINVAL;
+
+	if ((euid != (uid_t) -1) && !uid_valid(keuid))
+		return -EINVAL;
+
+	if ((suid != (uid_t) -1) && !uid_valid(ksuid))
+		return -EINVAL;
+
+	old = current_cred();
+
+	/* check for no-op */
+	if ((ruid == (uid_t) -1 || uid_eq(kruid, old->uid)) &&
+	    (euid == (uid_t) -1 || (uid_eq(keuid, old->euid) &&
+				    uid_eq(keuid, old->fsuid))) &&
+	    (suid == (uid_t) -1 || uid_eq(ksuid, old->suid)))
+		return 0;
+
+	ruid_new = ruid != (uid_t) -1        && !uid_eq(kruid, old->uid) &&
+		   !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid);
+	euid_new = euid != (uid_t) -1        && !uid_eq(keuid, old->uid) &&
+		   !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid);
+	suid_new = suid != (uid_t) -1        && !uid_eq(ksuid, old->uid) &&
+		   !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid);
+	if ((ruid_new || euid_new || suid_new) &&
+	    !ns_capable_setid(old->user_ns, CAP_SETUID))
+		return -EPERM;
+
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+
+	if (ruid != (uid_t) -1) {
+		new->uid = kruid;
+		if (!uid_eq(kruid, old->uid)) {
+			retval = set_user(new);
+			if (retval < 0)
+				goto error;
+		}
+	}
+	if (euid != (uid_t) -1)
+		new->euid = keuid;
+	if (suid != (uid_t) -1)
+		new->suid = ksuid;
+	new->fsuid = new->euid;
+
+	retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
+	if (retval < 0)
+		goto error;
+
+	retval = set_cred_ucounts(new);
+	if (retval < 0)
+		goto error;
+
+	flag_nproc_exceeded(new);
+	return commit_creds(new);
+
+error:
+	abort_creds(new);
+	return retval;
+}
+
+SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
+{
+	return __sys_setresuid(ruid, euid, suid);
+}
+
+SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
+{
+	const struct cred *cred = current_cred();
+	int retval;
+	uid_t ruid, euid, suid;
+
+	ruid = from_kuid_munged(cred->user_ns, cred->uid);
+	euid = from_kuid_munged(cred->user_ns, cred->euid);
+	suid = from_kuid_munged(cred->user_ns, cred->suid);
+
+	retval = put_user(ruid, ruidp);
+	if (!retval) {
+		retval = put_user(euid, euidp);
+		if (!retval)
+			return put_user(suid, suidp);
+	}
+	return retval;
+}
+
+/*
+ * Same as above, but for rgid, egid, sgid.
+ */
+long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
+{
+	struct user_namespace *ns = current_user_ns();
+	const struct cred *old;
+	struct cred *new;
+	int retval;
+	kgid_t krgid, kegid, ksgid;
+	bool rgid_new, egid_new, sgid_new;
+
+	krgid = make_kgid(ns, rgid);
+	kegid = make_kgid(ns, egid);
+	ksgid = make_kgid(ns, sgid);
+
+	if ((rgid != (gid_t) -1) && !gid_valid(krgid))
+		return -EINVAL;
+	if ((egid != (gid_t) -1) && !gid_valid(kegid))
+		return -EINVAL;
+	if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
+		return -EINVAL;
+
+	old = current_cred();
+
+	/* check for no-op */
+	if ((rgid == (gid_t) -1 || gid_eq(krgid, old->gid)) &&
+	    (egid == (gid_t) -1 || (gid_eq(kegid, old->egid) &&
+				    gid_eq(kegid, old->fsgid))) &&
+	    (sgid == (gid_t) -1 || gid_eq(ksgid, old->sgid)))
+		return 0;
+
+	rgid_new = rgid != (gid_t) -1        && !gid_eq(krgid, old->gid) &&
+		   !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid);
+	egid_new = egid != (gid_t) -1        && !gid_eq(kegid, old->gid) &&
+		   !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid);
+	sgid_new = sgid != (gid_t) -1        && !gid_eq(ksgid, old->gid) &&
+		   !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid);
+	if ((rgid_new || egid_new || sgid_new) &&
+	    !ns_capable_setid(old->user_ns, CAP_SETGID))
+		return -EPERM;
+
+	new = prepare_creds();
+	if (!new)
+		return -ENOMEM;
+
+	if (rgid != (gid_t) -1)
+		new->gid = krgid;
+	if (egid != (gid_t) -1)
+		new->egid = kegid;
+	if (sgid != (gid_t) -1)
+		new->sgid = ksgid;
+	new->fsgid = new->egid;
+
+	retval = security_task_fix_setgid(new, old, LSM_SETID_RES);
+	if (retval < 0)
+		goto error;
+
+	return commit_creds(new);
+
+error:
+	abort_creds(new);
+	return retval;
+}
+
+SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
+{
+	return __sys_setresgid(rgid, egid, sgid);
+}
+
+SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
+{
+	const struct cred *cred = current_cred();
+	int retval;
+	gid_t rgid, egid, sgid;
+
+	rgid = from_kgid_munged(cred->user_ns, cred->gid);
+	egid = from_kgid_munged(cred->user_ns, cred->egid);
+	sgid = from_kgid_munged(cred->user_ns, cred->sgid);
+
+	retval = put_user(rgid, rgidp);
+	if (!retval) {
+		retval = put_user(egid, egidp);
+		if (!retval)
+			retval = put_user(sgid, sgidp);
+	}
+
+	return retval;
+}
+
+
+/*
+ * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
+ * is used for "access()" and for the NFS daemon (letting nfsd stay at
+ * whatever uid it wants to). It normally shadows "euid", except when
+ * explicitly set by setfsuid() or for access..
+ */
+long __sys_setfsuid(uid_t uid)
+{
+	const struct cred *old;
+	struct cred *new;
+	uid_t old_fsuid;
+	kuid_t kuid;
+
+	old = current_cred();
+	old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
+
+	kuid = make_kuid(old->user_ns, uid);
+	if (!uid_valid(kuid))
+		return old_fsuid;
+
+	new = prepare_creds();
+	if (!new)
+		return old_fsuid;
+
+	if (uid_eq(kuid, old->uid)  || uid_eq(kuid, old->euid)  ||
+	    uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
+	    ns_capable_setid(old->user_ns, CAP_SETUID)) {
+		if (!uid_eq(kuid, old->fsuid)) {
+			new->fsuid = kuid;
+			if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
+				goto change_okay;
+		}
+	}
+
+	abort_creds(new);
+	return old_fsuid;
+
+change_okay:
+	commit_creds(new);
+	return old_fsuid;
+}
+
+SYSCALL_DEFINE1(setfsuid, uid_t, uid)
+{
+	return __sys_setfsuid(uid);
+}
+
+/*
+ * Samma på svenska..
+ */
+long __sys_setfsgid(gid_t gid)
+{
+	const struct cred *old;
+	struct cred *new;
+	gid_t old_fsgid;
+	kgid_t kgid;
+
+	old = current_cred();
+	old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
+
+	kgid = make_kgid(old->user_ns, gid);
+	if (!gid_valid(kgid))
+		return old_fsgid;
+
+	new = prepare_creds();
+	if (!new)
+		return old_fsgid;
+
+	if (gid_eq(kgid, old->gid)  || gid_eq(kgid, old->egid)  ||
+	    gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
+	    ns_capable_setid(old->user_ns, CAP_SETGID)) {
+		if (!gid_eq(kgid, old->fsgid)) {
+			new->fsgid = kgid;
+			if (security_task_fix_setgid(new,old,LSM_SETID_FS) == 0)
+				goto change_okay;
+		}
+	}
+
+	abort_creds(new);
+	return old_fsgid;
+
+change_okay:
+	commit_creds(new);
+	return old_fsgid;
+}
+
+SYSCALL_DEFINE1(setfsgid, gid_t, gid)
+{
+	return __sys_setfsgid(gid);
+}
+#endif /* CONFIG_MULTIUSER */
+
+/**
+ * sys_getpid - return the thread group id of the current process
+ *
+ * Note, despite the name, this returns the tgid not the pid.  The tgid and
+ * the pid are identical unless CLONE_THREAD was specified on clone() in
+ * which case the tgid is the same in all threads of the same group.
+ *
+ * This is SMP safe as current->tgid does not change.
+ */
+SYSCALL_DEFINE0(getpid)
+{
+	return task_tgid_vnr(current);
+}
+
+/* Thread ID - the internal kernel "pid" */
+SYSCALL_DEFINE0(gettid)
+{
+	return task_pid_vnr(current);
+}
+
+/*
+ * Accessing ->real_parent is not SMP-safe, it could
+ * change from under us. However, we can use a stale
+ * value of ->real_parent under rcu_read_lock(), see
+ * release_task()->call_rcu(delayed_put_task_struct).
+ */
+SYSCALL_DEFINE0(getppid)
+{
+	int pid;
+
+	rcu_read_lock();
+	pid = task_tgid_vnr(rcu_dereference(current->real_parent));
+	rcu_read_unlock();
+
+	return pid;
+}
+
+SYSCALL_DEFINE0(getuid)
+{
+	/* Only we change this so SMP safe */
+	return from_kuid_munged(current_user_ns(), current_uid());
+}
+
+SYSCALL_DEFINE0(geteuid)
+{
+	/* Only we change this so SMP safe */
+	return from_kuid_munged(current_user_ns(), current_euid());
+}
+
+SYSCALL_DEFINE0(getgid)
+{
+	/* Only we change this so SMP safe */
+	return from_kgid_munged(current_user_ns(), current_gid());
+}
+
+SYSCALL_DEFINE0(getegid)
+{
+	/* Only we change this so SMP safe */
+	return from_kgid_munged(current_user_ns(), current_egid());
+}
+
+static void do_sys_times(struct tms *tms)
+{
+	u64 tgutime, tgstime, cutime, cstime;
+
+	thread_group_cputime_adjusted(current, &tgutime, &tgstime);
+	cutime = current->signal->cutime;
+	cstime = current->signal->cstime;
+	tms->tms_utime = nsec_to_clock_t(tgutime);
+	tms->tms_stime = nsec_to_clock_t(tgstime);
+	tms->tms_cutime = nsec_to_clock_t(cutime);
+	tms->tms_cstime = nsec_to_clock_t(cstime);
+}
+
+SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
+{
+	if (tbuf) {
+		struct tms tmp;
+
+		do_sys_times(&tmp);
+		if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
+			return -EFAULT;
+	}
+	force_successful_syscall_return();
+	return (long) jiffies_64_to_clock_t(get_jiffies_64());
+}
+
+#ifdef CONFIG_COMPAT
+static compat_clock_t clock_t_to_compat_clock_t(clock_t x)
+{
+	return compat_jiffies_to_clock_t(clock_t_to_jiffies(x));
+}
+
+COMPAT_SYSCALL_DEFINE1(times, struct compat_tms __user *, tbuf)
+{
+	if (tbuf) {
+		struct tms tms;
+		struct compat_tms tmp;
+
+		do_sys_times(&tms);
+		/* Convert our struct tms to the compat version. */
+		tmp.tms_utime = clock_t_to_compat_clock_t(tms.tms_utime);
+		tmp.tms_stime = clock_t_to_compat_clock_t(tms.tms_stime);
+		tmp.tms_cutime = clock_t_to_compat_clock_t(tms.tms_cutime);
+		tmp.tms_cstime = clock_t_to_compat_clock_t(tms.tms_cstime);
+		if (copy_to_user(tbuf, &tmp, sizeof(tmp)))
+			return -EFAULT;
+	}
+	force_successful_syscall_return();
+	return compat_jiffies_to_clock_t(jiffies);
+}
+#endif
+
+/*
+ * This needs some heavy checking ...
+ * I just haven't the stomach for it. I also don't fully
+ * understand sessions/pgrp etc. Let somebody who does explain it.
+ *
+ * OK, I think I have the protection semantics right.... this is really
+ * only important on a multi-user system anyway, to make sure one user
+ * can't send a signal to a process owned by another.  -TYT, 12/12/91
+ *
+ * !PF_FORKNOEXEC check to conform completely to POSIX.
+ */
+SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
+{
+	struct task_struct *p;
+	struct task_struct *group_leader = current->group_leader;
+	struct pid *pgrp;
+	int err;
+
+	if (!pid)
+		pid = task_pid_vnr(group_leader);
+	if (!pgid)
+		pgid = pid;
+	if (pgid < 0)
+		return -EINVAL;
+	rcu_read_lock();
+
+	/* From this point forward we keep holding onto the tasklist lock
+	 * so that our parent does not change from under us. -DaveM
+	 */
+	write_lock_irq(&tasklist_lock);
+
+	err = -ESRCH;
+	p = find_task_by_vpid(pid);
+	if (!p)
+		goto out;
+
+	err = -EINVAL;
+	if (!thread_group_leader(p))
+		goto out;
+
+	if (same_thread_group(p->real_parent, group_leader)) {
+		err = -EPERM;
+		if (task_session(p) != task_session(group_leader))
+			goto out;
+		err = -EACCES;
+		if (!(p->flags & PF_FORKNOEXEC))
+			goto out;
+	} else {
+		err = -ESRCH;
+		if (p != group_leader)
+			goto out;
+	}
+
+	err = -EPERM;
+	if (p->signal->leader)
+		goto out;
+
+	pgrp = task_pid(p);
+	if (pgid != pid) {
+		struct task_struct *g;
+
+		pgrp = find_vpid(pgid);
+		g = pid_task(pgrp, PIDTYPE_PGID);
+		if (!g || task_session(g) != task_session(group_leader))
+			goto out;
+	}
+
+	err = security_task_setpgid(p, pgid);
+	if (err)
+		goto out;
+
+	if (task_pgrp(p) != pgrp)
+		change_pid(p, PIDTYPE_PGID, pgrp);
+
+	err = 0;
+out:
+	/* All paths lead to here, thus we are safe. -DaveM */
+	write_unlock_irq(&tasklist_lock);
+	rcu_read_unlock();
+	return err;
+}
+
+static int do_getpgid(pid_t pid)
+{
+	struct task_struct *p;
+	struct pid *grp;
+	int retval;
+
+	rcu_read_lock();
+	if (!pid)
+		grp = task_pgrp(current);
+	else {
+		retval = -ESRCH;
+		p = find_task_by_vpid(pid);
+		if (!p)
+			goto out;
+		grp = task_pgrp(p);
+		if (!grp)
+			goto out;
+
+		retval = security_task_getpgid(p);
+		if (retval)
+			goto out;
+	}
+	retval = pid_vnr(grp);
+out:
+	rcu_read_unlock();
+	return retval;
+}
+
+SYSCALL_DEFINE1(getpgid, pid_t, pid)
+{
+	return do_getpgid(pid);
+}
+
+#ifdef __ARCH_WANT_SYS_GETPGRP
+
+SYSCALL_DEFINE0(getpgrp)
+{
+	return do_getpgid(0);
+}
+
+#endif
+
+SYSCALL_DEFINE1(getsid, pid_t, pid)
+{
+	struct task_struct *p;
+	struct pid *sid;
+	int retval;
+
+	rcu_read_lock();
+	if (!pid)
+		sid = task_session(current);
+	else {
+		retval = -ESRCH;
+		p = find_task_by_vpid(pid);
+		if (!p)
+			goto out;
+		sid = task_session(p);
+		if (!sid)
+			goto out;
+
+		retval = security_task_getsid(p);
+		if (retval)
+			goto out;
+	}
+	retval = pid_vnr(sid);
+out:
+	rcu_read_unlock();
+	return retval;
+}
+
+static void set_special_pids(struct pid *pid)
+{
+	struct task_struct *curr = current->group_leader;
+
+	if (task_session(curr) != pid)
+		change_pid(curr, PIDTYPE_SID, pid);
+
+	if (task_pgrp(curr) != pid)
+		change_pid(curr, PIDTYPE_PGID, pid);
+}
+
+int ksys_setsid(void)
+{
+	struct task_struct *group_leader = current->group_leader;
+	struct pid *sid = task_pid(group_leader);
+	pid_t session = pid_vnr(sid);
+	int err = -EPERM;
+
+	write_lock_irq(&tasklist_lock);
+	/* Fail if I am already a session leader */
+	if (group_leader->signal->leader)
+		goto out;
+
+	/* Fail if a process group id already exists that equals the
+	 * proposed session id.
+	 */
+	if (pid_task(sid, PIDTYPE_PGID))
+		goto out;
+
+	group_leader->signal->leader = 1;
+	set_special_pids(sid);
+
+	proc_clear_tty(group_leader);
+
+	err = session;
+out:
+	write_unlock_irq(&tasklist_lock);
+	if (err > 0) {
+		proc_sid_connector(group_leader);
+		sched_autogroup_create_attach(group_leader);
+	}
+	return err;
+}
+
+SYSCALL_DEFINE0(setsid)
+{
+	return ksys_setsid();
+}
+
+DECLARE_RWSEM(uts_sem);
+
+#ifdef COMPAT_UTS_MACHINE
+#define override_architecture(name) \
+	(personality(current->personality) == PER_LINUX32 && \
+	 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
+		      sizeof(COMPAT_UTS_MACHINE)))
+#else
+#define override_architecture(name)	0
+#endif
+
+/*
+ * Work around broken programs that cannot handle "Linux 3.0".
+ * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
+ * And we map 4.x and later versions to 2.6.60+x, so 4.0/5.0/6.0/... would be
+ * 2.6.60.
+ */
+static int override_release(char __user *release, size_t len)
+{
+	int ret = 0;
+
+	if (current->personality & UNAME26) {
+		const char *rest = UTS_RELEASE;
+		char buf[65] = { 0 };
+		int ndots = 0;
+		unsigned v;
+		size_t copy;
+
+		while (*rest) {
+			if (*rest == '.' && ++ndots >= 3)
+				break;
+			if (!isdigit(*rest) && *rest != '.')
+				break;
+			rest++;
+		}
+		v = LINUX_VERSION_PATCHLEVEL + 60;
+		copy = clamp_t(size_t, len, 1, sizeof(buf));
+		copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
+		ret = copy_to_user(release, buf, copy + 1);
+	}
+	return ret;
+}
+
+SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
+{
+	struct new_utsname tmp;
+
+	down_read(&uts_sem);
+	memcpy(&tmp, utsname(), sizeof(tmp));
+	up_read(&uts_sem);
+	if (copy_to_user(name, &tmp, sizeof(tmp)))
+		return -EFAULT;
+
+	if (override_release(name->release, sizeof(name->release)))
+		return -EFAULT;
+	if (override_architecture(name))
+		return -EFAULT;
+	return 0;
+}
+
+#ifdef __ARCH_WANT_SYS_OLD_UNAME
+/*
+ * Old cruft
+ */
+SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
+{
+	struct old_utsname tmp;
+
+	if (!name)
+		return -EFAULT;
+
+	down_read(&uts_sem);
+	memcpy(&tmp, utsname(), sizeof(tmp));
+	up_read(&uts_sem);
+	if (copy_to_user(name, &tmp, sizeof(tmp)))
+		return -EFAULT;
+
+	if (override_release(name->release, sizeof(name->release)))
+		return -EFAULT;
+	if (override_architecture(name))
+		return -EFAULT;
+	return 0;
+}
+
+SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
+{
+	struct oldold_utsname tmp;
+
+	if (!name)
+		return -EFAULT;
+
+	memset(&tmp, 0, sizeof(tmp));
+
+	down_read(&uts_sem);
+	memcpy(&tmp.sysname, &utsname()->sysname, __OLD_UTS_LEN);
+	memcpy(&tmp.nodename, &utsname()->nodename, __OLD_UTS_LEN);
+	memcpy(&tmp.release, &utsname()->release, __OLD_UTS_LEN);
+	memcpy(&tmp.version, &utsname()->version, __OLD_UTS_LEN);
+	memcpy(&tmp.machine, &utsname()->machine, __OLD_UTS_LEN);
+	up_read(&uts_sem);
+	if (copy_to_user(name, &tmp, sizeof(tmp)))
+		return -EFAULT;
+
+	if (override_architecture(name))
+		return -EFAULT;
+	if (override_release(name->release, sizeof(name->release)))
+		return -EFAULT;
+	return 0;
+}
+#endif
+
+SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
+{
+	int errno;
+	char tmp[__NEW_UTS_LEN];
+
+	if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (len < 0 || len > __NEW_UTS_LEN)
+		return -EINVAL;
+	errno = -EFAULT;
+	if (!copy_from_user(tmp, name, len)) {
+		struct new_utsname *u;
+
+		add_device_randomness(tmp, len);
+		down_write(&uts_sem);
+		u = utsname();
+		memcpy(u->nodename, tmp, len);
+		memset(u->nodename + len, 0, sizeof(u->nodename) - len);
+		errno = 0;
+		uts_proc_notify(UTS_PROC_HOSTNAME);
+		up_write(&uts_sem);
+	}
+	return errno;
+}
+
+#ifdef __ARCH_WANT_SYS_GETHOSTNAME
+
+SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
+{
+	int i;
+	struct new_utsname *u;
+	char tmp[__NEW_UTS_LEN + 1];
+
+	if (len < 0)
+		return -EINVAL;
+	down_read(&uts_sem);
+	u = utsname();
+	i = 1 + strlen(u->nodename);
+	if (i > len)
+		i = len;
+	memcpy(tmp, u->nodename, i);
+	up_read(&uts_sem);
+	if (copy_to_user(name, tmp, i))
+		return -EFAULT;
+	return 0;
+}
+
+#endif
+
+/*
+ * Only setdomainname; getdomainname can be implemented by calling
+ * uname()
+ */
+SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
+{
+	int errno;
+	char tmp[__NEW_UTS_LEN];
+
+	if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+	if (len < 0 || len > __NEW_UTS_LEN)
+		return -EINVAL;
+
+	errno = -EFAULT;
+	if (!copy_from_user(tmp, name, len)) {
+		struct new_utsname *u;
+
+		add_device_randomness(tmp, len);
+		down_write(&uts_sem);
+		u = utsname();
+		memcpy(u->domainname, tmp, len);
+		memset(u->domainname + len, 0, sizeof(u->domainname) - len);
+		errno = 0;
+		uts_proc_notify(UTS_PROC_DOMAINNAME);
+		up_write(&uts_sem);
+	}
+	return errno;
+}
+
+/* make sure you are allowed to change @tsk limits before calling this */
+static int do_prlimit(struct task_struct *tsk, unsigned int resource,
+		      struct rlimit *new_rlim, struct rlimit *old_rlim)
+{
+	struct rlimit *rlim;
+	int retval = 0;
+
+	if (resource >= RLIM_NLIMITS)
+		return -EINVAL;
+	resource = array_index_nospec(resource, RLIM_NLIMITS);
+
+	if (new_rlim) {
+		if (new_rlim->rlim_cur > new_rlim->rlim_max)
+			return -EINVAL;
+		if (resource == RLIMIT_NOFILE &&
+				new_rlim->rlim_max > sysctl_nr_open)
+			return -EPERM;
+	}
+
+	/* Holding a refcount on tsk protects tsk->signal from disappearing. */
+	rlim = tsk->signal->rlim + resource;
+	task_lock(tsk->group_leader);
+	if (new_rlim) {
+		/*
+		 * Keep the capable check against init_user_ns until cgroups can
+		 * contain all limits.
+		 */
+		if (new_rlim->rlim_max > rlim->rlim_max &&
+				!capable(CAP_SYS_RESOURCE))
+			retval = -EPERM;
+		if (!retval)
+			retval = security_task_setrlimit(tsk, resource, new_rlim);
+	}
+	if (!retval) {
+		if (old_rlim)
+			*old_rlim = *rlim;
+		if (new_rlim)
+			*rlim = *new_rlim;
+	}
+	task_unlock(tsk->group_leader);
+
+	/*
+	 * RLIMIT_CPU handling. Arm the posix CPU timer if the limit is not
+	 * infinite. In case of RLIM_INFINITY the posix CPU timer code
+	 * ignores the rlimit.
+	 */
+	if (!retval && new_rlim && resource == RLIMIT_CPU &&
+	    new_rlim->rlim_cur != RLIM_INFINITY &&
+	    IS_ENABLED(CONFIG_POSIX_TIMERS)) {
+		/*
+		 * update_rlimit_cpu can fail if the task is exiting, but there
+		 * may be other tasks in the thread group that are not exiting,
+		 * and they need their cpu timers adjusted.
+		 *
+		 * The group_leader is the last task to be released, so if we
+		 * cannot update_rlimit_cpu on it, then the entire process is
+		 * exiting and we do not need to update at all.
+		 */
+		update_rlimit_cpu(tsk->group_leader, new_rlim->rlim_cur);
+	}
+
+	return retval;
+}
+
+SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
+{
+	struct rlimit value;
+	int ret;
+
+	ret = do_prlimit(current, resource, NULL, &value);
+	if (!ret)
+		ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
+
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT
+
+COMPAT_SYSCALL_DEFINE2(setrlimit, unsigned int, resource,
+		       struct compat_rlimit __user *, rlim)
+{
+	struct rlimit r;
+	struct compat_rlimit r32;
+
+	if (copy_from_user(&r32, rlim, sizeof(struct compat_rlimit)))
+		return -EFAULT;
+
+	if (r32.rlim_cur == COMPAT_RLIM_INFINITY)
+		r.rlim_cur = RLIM_INFINITY;
+	else
+		r.rlim_cur = r32.rlim_cur;
+	if (r32.rlim_max == COMPAT_RLIM_INFINITY)
+		r.rlim_max = RLIM_INFINITY;
+	else
+		r.rlim_max = r32.rlim_max;
+	return do_prlimit(current, resource, &r, NULL);
+}
+
+COMPAT_SYSCALL_DEFINE2(getrlimit, unsigned int, resource,
+		       struct compat_rlimit __user *, rlim)
+{
+	struct rlimit r;
+	int ret;
+
+	ret = do_prlimit(current, resource, NULL, &r);
+	if (!ret) {
+		struct compat_rlimit r32;
+		if (r.rlim_cur > COMPAT_RLIM_INFINITY)
+			r32.rlim_cur = COMPAT_RLIM_INFINITY;
+		else
+			r32.rlim_cur = r.rlim_cur;
+		if (r.rlim_max > COMPAT_RLIM_INFINITY)
+			r32.rlim_max = COMPAT_RLIM_INFINITY;
+		else
+			r32.rlim_max = r.rlim_max;
+
+		if (copy_to_user(rlim, &r32, sizeof(struct compat_rlimit)))
+			return -EFAULT;
+	}
+	return ret;
+}
+
+#endif
+
+#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
+
+/*
+ *	Back compatibility for getrlimit. Needed for some apps.
+ */
+SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
+		struct rlimit __user *, rlim)
+{
+	struct rlimit x;
+	if (resource >= RLIM_NLIMITS)
+		return -EINVAL;
+
+	resource = array_index_nospec(resource, RLIM_NLIMITS);
+	task_lock(current->group_leader);
+	x = current->signal->rlim[resource];
+	task_unlock(current->group_leader);
+	if (x.rlim_cur > 0x7FFFFFFF)
+		x.rlim_cur = 0x7FFFFFFF;
+	if (x.rlim_max > 0x7FFFFFFF)
+		x.rlim_max = 0x7FFFFFFF;
+	return copy_to_user(rlim, &x, sizeof(x)) ? -EFAULT : 0;
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
+		       struct compat_rlimit __user *, rlim)
+{
+	struct rlimit r;
+
+	if (resource >= RLIM_NLIMITS)
+		return -EINVAL;
+
+	resource = array_index_nospec(resource, RLIM_NLIMITS);
+	task_lock(current->group_leader);
+	r = current->signal->rlim[resource];
+	task_unlock(current->group_leader);
+	if (r.rlim_cur > 0x7FFFFFFF)
+		r.rlim_cur = 0x7FFFFFFF;
+	if (r.rlim_max > 0x7FFFFFFF)
+		r.rlim_max = 0x7FFFFFFF;
+
+	if (put_user(r.rlim_cur, &rlim->rlim_cur) ||
+	    put_user(r.rlim_max, &rlim->rlim_max))
+		return -EFAULT;
+	return 0;
+}
+#endif
+
+#endif
+
+static inline bool rlim64_is_infinity(__u64 rlim64)
+{
+#if BITS_PER_LONG < 64
+	return rlim64 >= ULONG_MAX;
+#else
+	return rlim64 == RLIM64_INFINITY;
+#endif
+}
+
+static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
+{
+	if (rlim->rlim_cur == RLIM_INFINITY)
+		rlim64->rlim_cur = RLIM64_INFINITY;
+	else
+		rlim64->rlim_cur = rlim->rlim_cur;
+	if (rlim->rlim_max == RLIM_INFINITY)
+		rlim64->rlim_max = RLIM64_INFINITY;
+	else
+		rlim64->rlim_max = rlim->rlim_max;
+}
+
+static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
+{
+	if (rlim64_is_infinity(rlim64->rlim_cur))
+		rlim->rlim_cur = RLIM_INFINITY;
+	else
+		rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
+	if (rlim64_is_infinity(rlim64->rlim_max))
+		rlim->rlim_max = RLIM_INFINITY;
+	else
+		rlim->rlim_max = (unsigned long)rlim64->rlim_max;
+}
+
+/* rcu lock must be held */
+static int check_prlimit_permission(struct task_struct *task,
+				    unsigned int flags)
+{
+	const struct cred *cred = current_cred(), *tcred;
+	bool id_match;
+
+	if (current == task)
+		return 0;
+
+	tcred = __task_cred(task);
+	id_match = (uid_eq(cred->uid, tcred->euid) &&
+		    uid_eq(cred->uid, tcred->suid) &&
+		    uid_eq(cred->uid, tcred->uid)  &&
+		    gid_eq(cred->gid, tcred->egid) &&
+		    gid_eq(cred->gid, tcred->sgid) &&
+		    gid_eq(cred->gid, tcred->gid));
+	if (!id_match && !ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
+		return -EPERM;
+
+	return security_task_prlimit(cred, tcred, flags);
+}
+
+SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
+		const struct rlimit64 __user *, new_rlim,
+		struct rlimit64 __user *, old_rlim)
+{
+	struct rlimit64 old64, new64;
+	struct rlimit old, new;
+	struct task_struct *tsk;
+	unsigned int checkflags = 0;
+	int ret;
+
+	if (old_rlim)
+		checkflags |= LSM_PRLIMIT_READ;
+
+	if (new_rlim) {
+		if (copy_from_user(&new64, new_rlim, sizeof(new64)))
+			return -EFAULT;
+		rlim64_to_rlim(&new64, &new);
+		checkflags |= LSM_PRLIMIT_WRITE;
+	}
+
+	rcu_read_lock();
+	tsk = pid ? find_task_by_vpid(pid) : current;
+	if (!tsk) {
+		rcu_read_unlock();
+		return -ESRCH;
+	}
+	ret = check_prlimit_permission(tsk, checkflags);
+	if (ret) {
+		rcu_read_unlock();
+		return ret;
+	}
+	get_task_struct(tsk);
+	rcu_read_unlock();
+
+	ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
+			old_rlim ? &old : NULL);
+
+	if (!ret && old_rlim) {
+		rlim_to_rlim64(&old, &old64);
+		if (copy_to_user(old_rlim, &old64, sizeof(old64)))
+			ret = -EFAULT;
+	}
+
+	put_task_struct(tsk);
+	return ret;
+}
+
+SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
+{
+	struct rlimit new_rlim;
+
+	if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
+		return -EFAULT;
+	return do_prlimit(current, resource, &new_rlim, NULL);
+}
+
+/*
+ * It would make sense to put struct rusage in the task_struct,
+ * except that would make the task_struct be *really big*.  After
+ * task_struct gets moved into malloc'ed memory, it would
+ * make sense to do this.  It will make moving the rest of the information
+ * a lot simpler!  (Which we're not doing right now because we're not
+ * measuring them yet).
+ *
+ * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
+ * races with threads incrementing their own counters.  But since word
+ * reads are atomic, we either get new values or old values and we don't
+ * care which for the sums.  We always take the siglock to protect reading
+ * the c* fields from p->signal from races with exit.c updating those
+ * fields when reaping, so a sample either gets all the additions of a
+ * given child after it's reaped, or none so this sample is before reaping.
+ *
+ * Locking:
+ * We need to take the siglock for CHILDEREN, SELF and BOTH
+ * for  the cases current multithreaded, non-current single threaded
+ * non-current multithreaded.  Thread traversal is now safe with
+ * the siglock held.
+ * Strictly speaking, we donot need to take the siglock if we are current and
+ * single threaded,  as no one else can take our signal_struct away, no one
+ * else can  reap the  children to update signal->c* counters, and no one else
+ * can race with the signal-> fields. If we do not take any lock, the
+ * signal-> fields could be read out of order while another thread was just
+ * exiting. So we should  place a read memory barrier when we avoid the lock.
+ * On the writer side,  write memory barrier is implied in  __exit_signal
+ * as __exit_signal releases  the siglock spinlock after updating the signal->
+ * fields. But we don't do this yet to keep things simple.
+ *
+ */
+
+static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
+{
+	r->ru_nvcsw += t->nvcsw;
+	r->ru_nivcsw += t->nivcsw;
+	r->ru_minflt += t->min_flt;
+	r->ru_majflt += t->maj_flt;
+	r->ru_inblock += task_io_get_inblock(t);
+	r->ru_oublock += task_io_get_oublock(t);
+}
+
+void getrusage(struct task_struct *p, int who, struct rusage *r)
+{
+	struct task_struct *t;
+	unsigned long flags;
+	u64 tgutime, tgstime, utime, stime;
+	unsigned long maxrss = 0;
+
+	memset((char *)r, 0, sizeof (*r));
+	utime = stime = 0;
+
+	if (who == RUSAGE_THREAD) {
+		task_cputime_adjusted(current, &utime, &stime);
+		accumulate_thread_rusage(p, r);
+		maxrss = p->signal->maxrss;
+		goto out;
+	}
+
+	if (!lock_task_sighand(p, &flags))
+		return;
+
+	switch (who) {
+	case RUSAGE_BOTH:
+	case RUSAGE_CHILDREN:
+		utime = p->signal->cutime;
+		stime = p->signal->cstime;
+		r->ru_nvcsw = p->signal->cnvcsw;
+		r->ru_nivcsw = p->signal->cnivcsw;
+		r->ru_minflt = p->signal->cmin_flt;
+		r->ru_majflt = p->signal->cmaj_flt;
+		r->ru_inblock = p->signal->cinblock;
+		r->ru_oublock = p->signal->coublock;
+		maxrss = p->signal->cmaxrss;
+
+		if (who == RUSAGE_CHILDREN)
+			break;
+		fallthrough;
+
+	case RUSAGE_SELF:
+		thread_group_cputime_adjusted(p, &tgutime, &tgstime);
+		utime += tgutime;
+		stime += tgstime;
+		r->ru_nvcsw += p->signal->nvcsw;
+		r->ru_nivcsw += p->signal->nivcsw;
+		r->ru_minflt += p->signal->min_flt;
+		r->ru_majflt += p->signal->maj_flt;
+		r->ru_inblock += p->signal->inblock;
+		r->ru_oublock += p->signal->oublock;
+		if (maxrss < p->signal->maxrss)
+			maxrss = p->signal->maxrss;
+		t = p;
+		do {
+			accumulate_thread_rusage(t, r);
+		} while_each_thread(p, t);
+		break;
+
+	default:
+		BUG();
+	}
+	unlock_task_sighand(p, &flags);
+
+out:
+	r->ru_utime = ns_to_kernel_old_timeval(utime);
+	r->ru_stime = ns_to_kernel_old_timeval(stime);
+
+	if (who != RUSAGE_CHILDREN) {
+		struct mm_struct *mm = get_task_mm(p);
+
+		if (mm) {
+			setmax_mm_hiwater_rss(&maxrss, mm);
+			mmput(mm);
+		}
+	}
+	r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
+}
+
+SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
+{
+	struct rusage r;
+
+	if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
+	    who != RUSAGE_THREAD)
+		return -EINVAL;
+
+	getrusage(current, who, &r);
+	return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(getrusage, int, who, struct compat_rusage __user *, ru)
+{
+	struct rusage r;
+
+	if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
+	    who != RUSAGE_THREAD)
+		return -EINVAL;
+
+	getrusage(current, who, &r);
+	return put_compat_rusage(&r, ru);
+}
+#endif
+
+SYSCALL_DEFINE1(umask, int, mask)
+{
+	mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
+	return mask;
+}
+
+static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
+{
+	struct fd exe;
+	struct inode *inode;
+	int err;
+
+	exe = fdget(fd);
+	if (!exe.file)
+		return -EBADF;
+
+	inode = file_inode(exe.file);
+
+	/*
+	 * Because the original mm->exe_file points to executable file, make
+	 * sure that this one is executable as well, to avoid breaking an
+	 * overall picture.
+	 */
+	err = -EACCES;
+	if (!S_ISREG(inode->i_mode) || path_noexec(&exe.file->f_path))
+		goto exit;
+
+	err = file_permission(exe.file, MAY_EXEC);
+	if (err)
+		goto exit;
+
+	err = replace_mm_exe_file(mm, exe.file);
+exit:
+	fdput(exe);
+	return err;
+}
+
+/*
+ * Check arithmetic relations of passed addresses.
+ *
+ * WARNING: we don't require any capability here so be very careful
+ * in what is allowed for modification from userspace.
+ */
+static int validate_prctl_map_addr(struct prctl_mm_map *prctl_map)
+{
+	unsigned long mmap_max_addr = TASK_SIZE;
+	int error = -EINVAL, i;
+
+	static const unsigned char offsets[] = {
+		offsetof(struct prctl_mm_map, start_code),
+		offsetof(struct prctl_mm_map, end_code),
+		offsetof(struct prctl_mm_map, start_data),
+		offsetof(struct prctl_mm_map, end_data),
+		offsetof(struct prctl_mm_map, start_brk),
+		offsetof(struct prctl_mm_map, brk),
+		offsetof(struct prctl_mm_map, start_stack),
+		offsetof(struct prctl_mm_map, arg_start),
+		offsetof(struct prctl_mm_map, arg_end),
+		offsetof(struct prctl_mm_map, env_start),
+		offsetof(struct prctl_mm_map, env_end),
+	};
+
+	/*
+	 * Make sure the members are not somewhere outside
+	 * of allowed address space.
+	 */
+	for (i = 0; i < ARRAY_SIZE(offsets); i++) {
+		u64 val = *(u64 *)((char *)prctl_map + offsets[i]);
+
+		if ((unsigned long)val >= mmap_max_addr ||
+		    (unsigned long)val < mmap_min_addr)
+			goto out;
+	}
+
+	/*
+	 * Make sure the pairs are ordered.
+	 */
+#define __prctl_check_order(__m1, __op, __m2)				\
+	((unsigned long)prctl_map->__m1 __op				\
+	 (unsigned long)prctl_map->__m2) ? 0 : -EINVAL
+	error  = __prctl_check_order(start_code, <, end_code);
+	error |= __prctl_check_order(start_data,<=, end_data);
+	error |= __prctl_check_order(start_brk, <=, brk);
+	error |= __prctl_check_order(arg_start, <=, arg_end);
+	error |= __prctl_check_order(env_start, <=, env_end);
+	if (error)
+		goto out;
+#undef __prctl_check_order
+
+	error = -EINVAL;
+
+	/*
+	 * Neither we should allow to override limits if they set.
+	 */
+	if (check_data_rlimit(rlimit(RLIMIT_DATA), prctl_map->brk,
+			      prctl_map->start_brk, prctl_map->end_data,
+			      prctl_map->start_data))
+			goto out;
+
+	error = 0;
+out:
+	return error;
+}
+
+#ifdef CONFIG_CHECKPOINT_RESTORE
+static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data_size)
+{
+	struct prctl_mm_map prctl_map = { .exe_fd = (u32)-1, };
+	unsigned long user_auxv[AT_VECTOR_SIZE];
+	struct mm_struct *mm = current->mm;
+	int error;
+
+	BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
+	BUILD_BUG_ON(sizeof(struct prctl_mm_map) > 256);
+
+	if (opt == PR_SET_MM_MAP_SIZE)
+		return put_user((unsigned int)sizeof(prctl_map),
+				(unsigned int __user *)addr);
+
+	if (data_size != sizeof(prctl_map))
+		return -EINVAL;
+
+	if (copy_from_user(&prctl_map, addr, sizeof(prctl_map)))
+		return -EFAULT;
+
+	error = validate_prctl_map_addr(&prctl_map);
+	if (error)
+		return error;
+
+	if (prctl_map.auxv_size) {
+		/*
+		 * Someone is trying to cheat the auxv vector.
+		 */
+		if (!prctl_map.auxv ||
+				prctl_map.auxv_size > sizeof(mm->saved_auxv))
+			return -EINVAL;
+
+		memset(user_auxv, 0, sizeof(user_auxv));
+		if (copy_from_user(user_auxv,
+				   (const void __user *)prctl_map.auxv,
+				   prctl_map.auxv_size))
+			return -EFAULT;
+
+		/* Last entry must be AT_NULL as specification requires */
+		user_auxv[AT_VECTOR_SIZE - 2] = AT_NULL;
+		user_auxv[AT_VECTOR_SIZE - 1] = AT_NULL;
+	}
+
+	if (prctl_map.exe_fd != (u32)-1) {
+		/*
+		 * Check if the current user is checkpoint/restore capable.
+		 * At the time of this writing, it checks for CAP_SYS_ADMIN
+		 * or CAP_CHECKPOINT_RESTORE.
+		 * Note that a user with access to ptrace can masquerade an
+		 * arbitrary program as any executable, even setuid ones.
+		 * This may have implications in the tomoyo subsystem.
+		 */
+		if (!checkpoint_restore_ns_capable(current_user_ns()))
+			return -EPERM;
+
+		error = prctl_set_mm_exe_file(mm, prctl_map.exe_fd);
+		if (error)
+			return error;
+	}
+
+	/*
+	 * arg_lock protects concurrent updates but we still need mmap_lock for
+	 * read to exclude races with sys_brk.
+	 */
+	mmap_read_lock(mm);
+
+	/*
+	 * We don't validate if these members are pointing to
+	 * real present VMAs because application may have correspond
+	 * VMAs already unmapped and kernel uses these members for statistics
+	 * output in procfs mostly, except
+	 *
+	 *  - @start_brk/@brk which are used in do_brk_flags but kernel lookups
+	 *    for VMAs when updating these members so anything wrong written
+	 *    here cause kernel to swear at userspace program but won't lead
+	 *    to any problem in kernel itself
+	 */
+
+	spin_lock(&mm->arg_lock);
+	mm->start_code	= prctl_map.start_code;
+	mm->end_code	= prctl_map.end_code;
+	mm->start_data	= prctl_map.start_data;
+	mm->end_data	= prctl_map.end_data;
+	mm->start_brk	= prctl_map.start_brk;
+	mm->brk		= prctl_map.brk;
+	mm->start_stack	= prctl_map.start_stack;
+	mm->arg_start	= prctl_map.arg_start;
+	mm->arg_end	= prctl_map.arg_end;
+	mm->env_start	= prctl_map.env_start;
+	mm->env_end	= prctl_map.env_end;
+	spin_unlock(&mm->arg_lock);
+
+	/*
+	 * Note this update of @saved_auxv is lockless thus
+	 * if someone reads this member in procfs while we're
+	 * updating -- it may get partly updated results. It's
+	 * known and acceptable trade off: we leave it as is to
+	 * not introduce additional locks here making the kernel
+	 * more complex.
+	 */
+	if (prctl_map.auxv_size)
+		memcpy(mm->saved_auxv, user_auxv, sizeof(user_auxv));
+
+	mmap_read_unlock(mm);
+	return 0;
+}
+#endif /* CONFIG_CHECKPOINT_RESTORE */
+
+static int prctl_set_auxv(struct mm_struct *mm, unsigned long addr,
+			  unsigned long len)
+{
+	/*
+	 * This doesn't move the auxiliary vector itself since it's pinned to
+	 * mm_struct, but it permits filling the vector with new values.  It's
+	 * up to the caller to provide sane values here, otherwise userspace
+	 * tools which use this vector might be unhappy.
+	 */
+	unsigned long user_auxv[AT_VECTOR_SIZE] = {};
+
+	if (len > sizeof(user_auxv))
+		return -EINVAL;
+
+	if (copy_from_user(user_auxv, (const void __user *)addr, len))
+		return -EFAULT;
+
+	/* Make sure the last entry is always AT_NULL */
+	user_auxv[AT_VECTOR_SIZE - 2] = 0;
+	user_auxv[AT_VECTOR_SIZE - 1] = 0;
+
+	BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
+
+	task_lock(current);
+	memcpy(mm->saved_auxv, user_auxv, len);
+	task_unlock(current);
+
+	return 0;
+}
+
+static int prctl_set_mm(int opt, unsigned long addr,
+			unsigned long arg4, unsigned long arg5)
+{
+	struct mm_struct *mm = current->mm;
+	struct prctl_mm_map prctl_map = {
+		.auxv = NULL,
+		.auxv_size = 0,
+		.exe_fd = -1,
+	};
+	struct vm_area_struct *vma;
+	int error;
+
+	if (arg5 || (arg4 && (opt != PR_SET_MM_AUXV &&
+			      opt != PR_SET_MM_MAP &&
+			      opt != PR_SET_MM_MAP_SIZE)))
+		return -EINVAL;
+
+#ifdef CONFIG_CHECKPOINT_RESTORE
+	if (opt == PR_SET_MM_MAP || opt == PR_SET_MM_MAP_SIZE)
+		return prctl_set_mm_map(opt, (const void __user *)addr, arg4);
+#endif
+
+	if (!capable(CAP_SYS_RESOURCE))
+		return -EPERM;
+
+	if (opt == PR_SET_MM_EXE_FILE)
+		return prctl_set_mm_exe_file(mm, (unsigned int)addr);
+
+	if (opt == PR_SET_MM_AUXV)
+		return prctl_set_auxv(mm, addr, arg4);
+
+	if (addr >= TASK_SIZE || addr < mmap_min_addr)
+		return -EINVAL;
+
+	error = -EINVAL;
+
+	/*
+	 * arg_lock protects concurrent updates of arg boundaries, we need
+	 * mmap_lock for a) concurrent sys_brk, b) finding VMA for addr
+	 * validation.
+	 */
+	mmap_read_lock(mm);
+	vma = find_vma(mm, addr);
+
+	spin_lock(&mm->arg_lock);
+	prctl_map.start_code	= mm->start_code;
+	prctl_map.end_code	= mm->end_code;
+	prctl_map.start_data	= mm->start_data;
+	prctl_map.end_data	= mm->end_data;
+	prctl_map.start_brk	= mm->start_brk;
+	prctl_map.brk		= mm->brk;
+	prctl_map.start_stack	= mm->start_stack;
+	prctl_map.arg_start	= mm->arg_start;
+	prctl_map.arg_end	= mm->arg_end;
+	prctl_map.env_start	= mm->env_start;
+	prctl_map.env_end	= mm->env_end;
+
+	switch (opt) {
+	case PR_SET_MM_START_CODE:
+		prctl_map.start_code = addr;
+		break;
+	case PR_SET_MM_END_CODE:
+		prctl_map.end_code = addr;
+		break;
+	case PR_SET_MM_START_DATA:
+		prctl_map.start_data = addr;
+		break;
+	case PR_SET_MM_END_DATA:
+		prctl_map.end_data = addr;
+		break;
+	case PR_SET_MM_START_STACK:
+		prctl_map.start_stack = addr;
+		break;
+	case PR_SET_MM_START_BRK:
+		prctl_map.start_brk = addr;
+		break;
+	case PR_SET_MM_BRK:
+		prctl_map.brk = addr;
+		break;
+	case PR_SET_MM_ARG_START:
+		prctl_map.arg_start = addr;
+		break;
+	case PR_SET_MM_ARG_END:
+		prctl_map.arg_end = addr;
+		break;
+	case PR_SET_MM_ENV_START:
+		prctl_map.env_start = addr;
+		break;
+	case PR_SET_MM_ENV_END:
+		prctl_map.env_end = addr;
+		break;
+	default:
+		goto out;
+	}
+
+	error = validate_prctl_map_addr(&prctl_map);
+	if (error)
+		goto out;
+
+	switch (opt) {
+	/*
+	 * If command line arguments and environment
+	 * are placed somewhere else on stack, we can
+	 * set them up here, ARG_START/END to setup
+	 * command line arguments and ENV_START/END
+	 * for environment.
+	 */
+	case PR_SET_MM_START_STACK:
+	case PR_SET_MM_ARG_START:
+	case PR_SET_MM_ARG_END:
+	case PR_SET_MM_ENV_START:
+	case PR_SET_MM_ENV_END:
+		if (!vma) {
+			error = -EFAULT;
+			goto out;
+		}
+	}
+
+	mm->start_code	= prctl_map.start_code;
+	mm->end_code	= prctl_map.end_code;
+	mm->start_data	= prctl_map.start_data;
+	mm->end_data	= prctl_map.end_data;
+	mm->start_brk	= prctl_map.start_brk;
+	mm->brk		= prctl_map.brk;
+	mm->start_stack	= prctl_map.start_stack;
+	mm->arg_start	= prctl_map.arg_start;
+	mm->arg_end	= prctl_map.arg_end;
+	mm->env_start	= prctl_map.env_start;
+	mm->env_end	= prctl_map.env_end;
+
+	error = 0;
+out:
+	spin_unlock(&mm->arg_lock);
+	mmap_read_unlock(mm);
+	return error;
+}
+
+#ifdef CONFIG_CHECKPOINT_RESTORE
+static int prctl_get_tid_address(struct task_struct *me, int __user * __user *tid_addr)
+{
+	return put_user(me->clear_child_tid, tid_addr);
+}
+#else
+static int prctl_get_tid_address(struct task_struct *me, int __user * __user *tid_addr)
+{
+	return -EINVAL;
+}
+#endif
+
+static int propagate_has_child_subreaper(struct task_struct *p, void *data)
+{
+	/*
+	 * If task has has_child_subreaper - all its descendants
+	 * already have these flag too and new descendants will
+	 * inherit it on fork, skip them.
+	 *
+	 * If we've found child_reaper - skip descendants in
+	 * it's subtree as they will never get out pidns.
+	 */
+	if (p->signal->has_child_subreaper ||
+	    is_child_reaper(task_pid(p)))
+		return 0;
+
+	p->signal->has_child_subreaper = 1;
+	return 1;
+}
+
+int __weak arch_prctl_spec_ctrl_get(struct task_struct *t, unsigned long which)
+{
+	return -EINVAL;
+}
+
+int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which,
+				    unsigned long ctrl)
+{
+	return -EINVAL;
+}
+
+#define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LOCAL_THROTTLE)
+
+#ifdef CONFIG_ANON_VMA_NAME
+
+#define ANON_VMA_NAME_MAX_LEN		80
+#define ANON_VMA_NAME_INVALID_CHARS	"\\`$[]"
+
+static inline bool is_valid_name_char(char ch)
+{
+	/* printable ascii characters, excluding ANON_VMA_NAME_INVALID_CHARS */
+	return ch > 0x1f && ch < 0x7f &&
+		!strchr(ANON_VMA_NAME_INVALID_CHARS, ch);
+}
+
+static int prctl_set_vma(unsigned long opt, unsigned long addr,
+			 unsigned long size, unsigned long arg)
+{
+	struct mm_struct *mm = current->mm;
+	const char __user *uname;
+	struct anon_vma_name *anon_name = NULL;
+	int error;
+
+	switch (opt) {
+	case PR_SET_VMA_ANON_NAME:
+		uname = (const char __user *)arg;
+		if (uname) {
+			char *name, *pch;
+
+			name = strndup_user(uname, ANON_VMA_NAME_MAX_LEN);
+			if (IS_ERR(name))
+				return PTR_ERR(name);
+
+			for (pch = name; *pch != '\0'; pch++) {
+				if (!is_valid_name_char(*pch)) {
+					kfree(name);
+					return -EINVAL;
+				}
+			}
+			/* anon_vma has its own copy */
+			anon_name = anon_vma_name_alloc(name);
+			kfree(name);
+			if (!anon_name)
+				return -ENOMEM;
+
+		}
+
+		mmap_write_lock(mm);
+		error = madvise_set_anon_name(mm, addr, size, anon_name);
+		mmap_write_unlock(mm);
+		anon_vma_name_put(anon_name);
+		break;
+	default:
+		error = -EINVAL;
+	}
+
+	return error;
+}
+
+#else /* CONFIG_ANON_VMA_NAME */
+static int prctl_set_vma(unsigned long opt, unsigned long start,
+			 unsigned long size, unsigned long arg)
+{
+	return -EINVAL;
+}
+#endif /* CONFIG_ANON_VMA_NAME */
+
+SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
+		unsigned long, arg4, unsigned long, arg5)
+{
+	struct task_struct *me = current;
+	unsigned char comm[sizeof(me->comm)];
+	long error;
+
+	error = security_task_prctl(option, arg2, arg3, arg4, arg5);
+	if (error != -ENOSYS)
+		return error;
+
+	error = 0;
+	switch (option) {
+	case PR_SET_PDEATHSIG:
+		if (!valid_signal(arg2)) {
+			error = -EINVAL;
+			break;
+		}
+		me->pdeath_signal = arg2;
+		break;
+	case PR_GET_PDEATHSIG:
+		error = put_user(me->pdeath_signal, (int __user *)arg2);
+		break;
+	case PR_GET_DUMPABLE:
+		error = get_dumpable(me->mm);
+		break;
+	case PR_SET_DUMPABLE:
+		if (arg2 != SUID_DUMP_DISABLE && arg2 != SUID_DUMP_USER) {
+			error = -EINVAL;
+			break;
+		}
+		set_dumpable(me->mm, arg2);
+		break;
+
+	case PR_SET_UNALIGN:
+		error = SET_UNALIGN_CTL(me, arg2);
+		break;
+	case PR_GET_UNALIGN:
+		error = GET_UNALIGN_CTL(me, arg2);
+		break;
+	case PR_SET_FPEMU:
+		error = SET_FPEMU_CTL(me, arg2);
+		break;
+	case PR_GET_FPEMU:
+		error = GET_FPEMU_CTL(me, arg2);
+		break;
+	case PR_SET_FPEXC:
+		error = SET_FPEXC_CTL(me, arg2);
+		break;
+	case PR_GET_FPEXC:
+		error = GET_FPEXC_CTL(me, arg2);
+		break;
+	case PR_GET_TIMING:
+		error = PR_TIMING_STATISTICAL;
+		break;
+	case PR_SET_TIMING:
+		if (arg2 != PR_TIMING_STATISTICAL)
+			error = -EINVAL;
+		break;
+	case PR_SET_NAME:
+		comm[sizeof(me->comm) - 1] = 0;
+		if (strncpy_from_user(comm, (char __user *)arg2,
+				      sizeof(me->comm) - 1) < 0)
+			return -EFAULT;
+		set_task_comm(me, comm);
+		proc_comm_connector(me);
+		break;
+	case PR_GET_NAME:
+		get_task_comm(comm, me);
+		if (copy_to_user((char __user *)arg2, comm, sizeof(comm)))
+			return -EFAULT;
+		break;
+	case PR_GET_ENDIAN:
+		error = GET_ENDIAN(me, arg2);
+		break;
+	case PR_SET_ENDIAN:
+		error = SET_ENDIAN(me, arg2);
+		break;
+	case PR_GET_SECCOMP:
+		error = prctl_get_seccomp();
+		break;
+	case PR_SET_SECCOMP:
+		error = prctl_set_seccomp(arg2, (char __user *)arg3);
+		break;
+	case PR_GET_TSC:
+		error = GET_TSC_CTL(arg2);
+		break;
+	case PR_SET_TSC:
+		error = SET_TSC_CTL(arg2);
+		break;
+	case PR_TASK_PERF_EVENTS_DISABLE:
+		error = perf_event_task_disable();
+		break;
+	case PR_TASK_PERF_EVENTS_ENABLE:
+		error = perf_event_task_enable();
+		break;
+	case PR_GET_TIMERSLACK:
+		if (current->timer_slack_ns > ULONG_MAX)
+			error = ULONG_MAX;
+		else
+			error = current->timer_slack_ns;
+		break;
+	case PR_SET_TIMERSLACK:
+		if (arg2 <= 0)
+			current->timer_slack_ns =
+					current->default_timer_slack_ns;
+		else
+			current->timer_slack_ns = arg2;
+		break;
+	case PR_MCE_KILL:
+		if (arg4 | arg5)
+			return -EINVAL;
+		switch (arg2) {
+		case PR_MCE_KILL_CLEAR:
+			if (arg3 != 0)
+				return -EINVAL;
+			current->flags &= ~PF_MCE_PROCESS;
+			break;
+		case PR_MCE_KILL_SET:
+			current->flags |= PF_MCE_PROCESS;
+			if (arg3 == PR_MCE_KILL_EARLY)
+				current->flags |= PF_MCE_EARLY;
+			else if (arg3 == PR_MCE_KILL_LATE)
+				current->flags &= ~PF_MCE_EARLY;
+			else if (arg3 == PR_MCE_KILL_DEFAULT)
+				current->flags &=
+						~(PF_MCE_EARLY|PF_MCE_PROCESS);
+			else
+				return -EINVAL;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case PR_MCE_KILL_GET:
+		if (arg2 | arg3 | arg4 | arg5)
+			return -EINVAL;
+		if (current->flags & PF_MCE_PROCESS)
+			error = (current->flags & PF_MCE_EARLY) ?
+				PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
+		else
+			error = PR_MCE_KILL_DEFAULT;
+		break;
+	case PR_SET_MM:
+		error = prctl_set_mm(arg2, arg3, arg4, arg5);
+		break;
+	case PR_GET_TID_ADDRESS:
+		error = prctl_get_tid_address(me, (int __user * __user *)arg2);
+		break;
+	case PR_SET_CHILD_SUBREAPER:
+		me->signal->is_child_subreaper = !!arg2;
+		if (!arg2)
+			break;
+
+		walk_process_tree(me, propagate_has_child_subreaper, NULL);
+		break;
+	case PR_GET_CHILD_SUBREAPER:
+		error = put_user(me->signal->is_child_subreaper,
+				 (int __user *)arg2);
+		break;
+	case PR_SET_NO_NEW_PRIVS:
+		if (arg2 != 1 || arg3 || arg4 || arg5)
+			return -EINVAL;
+
+		task_set_no_new_privs(current);
+		break;
+	case PR_GET_NO_NEW_PRIVS:
+		if (arg2 || arg3 || arg4 || arg5)
+			return -EINVAL;
+		return task_no_new_privs(current) ? 1 : 0;
+	case PR_GET_THP_DISABLE:
+		if (arg2 || arg3 || arg4 || arg5)
+			return -EINVAL;
+		error = !!test_bit(MMF_DISABLE_THP, &me->mm->flags);
+		break;
+	case PR_SET_THP_DISABLE:
+		if (arg3 || arg4 || arg5)
+			return -EINVAL;
+		if (mmap_write_lock_killable(me->mm))
+			return -EINTR;
+		if (arg2)
+			set_bit(MMF_DISABLE_THP, &me->mm->flags);
+		else
+			clear_bit(MMF_DISABLE_THP, &me->mm->flags);
+		mmap_write_unlock(me->mm);
+		break;
+	case PR_MPX_ENABLE_MANAGEMENT:
+	case PR_MPX_DISABLE_MANAGEMENT:
+		/* No longer implemented: */
+		return -EINVAL;
+	case PR_SET_FP_MODE:
+		error = SET_FP_MODE(me, arg2);
+		break;
+	case PR_GET_FP_MODE:
+		error = GET_FP_MODE(me);
+		break;
+	case PR_SVE_SET_VL:
+		error = SVE_SET_VL(arg2);
+		break;
+	case PR_SVE_GET_VL:
+		error = SVE_GET_VL();
+		break;
+	case PR_SME_SET_VL:
+		error = SME_SET_VL(arg2);
+		break;
+	case PR_SME_GET_VL:
+		error = SME_GET_VL();
+		break;
+	case PR_GET_SPECULATION_CTRL:
+		if (arg3 || arg4 || arg5)
+			return -EINVAL;
+		error = arch_prctl_spec_ctrl_get(me, arg2);
+		break;
+	case PR_SET_SPECULATION_CTRL:
+		if (arg4 || arg5)
+			return -EINVAL;
+		error = arch_prctl_spec_ctrl_set(me, arg2, arg3);
+		break;
+	case PR_PAC_RESET_KEYS:
+		if (arg3 || arg4 || arg5)
+			return -EINVAL;
+		error = PAC_RESET_KEYS(me, arg2);
+		break;
+	case PR_PAC_SET_ENABLED_KEYS:
+		if (arg4 || arg5)
+			return -EINVAL;
+		error = PAC_SET_ENABLED_KEYS(me, arg2, arg3);
+		break;
+	case PR_PAC_GET_ENABLED_KEYS:
+		if (arg2 || arg3 || arg4 || arg5)
+			return -EINVAL;
+		error = PAC_GET_ENABLED_KEYS(me);
+		break;
+	case PR_SET_TAGGED_ADDR_CTRL:
+		if (arg3 || arg4 || arg5)
+			return -EINVAL;
+		error = SET_TAGGED_ADDR_CTRL(arg2);
+		break;
+	case PR_GET_TAGGED_ADDR_CTRL:
+		if (arg2 || arg3 || arg4 || arg5)
+			return -EINVAL;
+		error = GET_TAGGED_ADDR_CTRL();
+		break;
+	case PR_SET_IO_FLUSHER:
+		if (!capable(CAP_SYS_RESOURCE))
+			return -EPERM;
+
+		if (arg3 || arg4 || arg5)
+			return -EINVAL;
+
+		if (arg2 == 1)
+			current->flags |= PR_IO_FLUSHER;
+		else if (!arg2)
+			current->flags &= ~PR_IO_FLUSHER;
+		else
+			return -EINVAL;
+		break;
+	case PR_GET_IO_FLUSHER:
+		if (!capable(CAP_SYS_RESOURCE))
+			return -EPERM;
+
+		if (arg2 || arg3 || arg4 || arg5)
+			return -EINVAL;
+
+		error = (current->flags & PR_IO_FLUSHER) == PR_IO_FLUSHER;
+		break;
+	case PR_SET_SYSCALL_USER_DISPATCH:
+		error = set_syscall_user_dispatch(arg2, arg3, arg4,
+						  (char __user *) arg5);
+		break;
+#ifdef CONFIG_SCHED_CORE
+	case PR_SCHED_CORE:
+		error = sched_core_share_pid(arg2, arg3, arg4, arg5);
+		break;
+#endif
+	case PR_SET_VMA:
+		error = prctl_set_vma(arg2, arg3, arg4, arg5);
+		break;
+	default:
+		error = -EINVAL;
+		break;
+	}
+	return error;
+}
+
+SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
+		struct getcpu_cache __user *, unused)
+{
+	int err = 0;
+	int cpu = raw_smp_processor_id();
+
+	if (cpup)
+		err |= put_user(cpu, cpup);
+	if (nodep)
+		err |= put_user(cpu_to_node(cpu), nodep);
+	return err ? -EFAULT : 0;
+}
+
+/**
+ * do_sysinfo - fill in sysinfo struct
+ * @info: pointer to buffer to fill
+ */
+static int do_sysinfo(struct sysinfo *info)
+{
+	unsigned long mem_total, sav_total;
+	unsigned int mem_unit, bitcount;
+	struct timespec64 tp;
+
+	memset(info, 0, sizeof(struct sysinfo));
+
+	ktime_get_boottime_ts64(&tp);
+	timens_add_boottime(&tp);
+	info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
+
+	get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
+
+	info->procs = nr_threads;
+
+	si_meminfo(info);
+	si_swapinfo(info);
+
+	/*
+	 * If the sum of all the available memory (i.e. ram + swap)
+	 * is less than can be stored in a 32 bit unsigned long then
+	 * we can be binary compatible with 2.2.x kernels.  If not,
+	 * well, in that case 2.2.x was broken anyways...
+	 *
+	 *  -Erik Andersen <andersee@debian.org>
+	 */
+
+	mem_total = info->totalram + info->totalswap;
+	if (mem_total < info->totalram || mem_total < info->totalswap)
+		goto out;
+	bitcount = 0;
+	mem_unit = info->mem_unit;
+	while (mem_unit > 1) {
+		bitcount++;
+		mem_unit >>= 1;
+		sav_total = mem_total;
+		mem_total <<= 1;
+		if (mem_total < sav_total)
+			goto out;
+	}
+
+	/*
+	 * If mem_total did not overflow, multiply all memory values by
+	 * info->mem_unit and set it to 1.  This leaves things compatible
+	 * with 2.2.x, and also retains compatibility with earlier 2.4.x
+	 * kernels...
+	 */
+
+	info->mem_unit = 1;
+	info->totalram <<= bitcount;
+	info->freeram <<= bitcount;
+	info->sharedram <<= bitcount;
+	info->bufferram <<= bitcount;
+	info->totalswap <<= bitcount;
+	info->freeswap <<= bitcount;
+	info->totalhigh <<= bitcount;
+	info->freehigh <<= bitcount;
+
+out:
+	return 0;
+}
+
+SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info)
+{
+	struct sysinfo val;
+
+	do_sysinfo(&val);
+
+	if (copy_to_user(info, &val, sizeof(struct sysinfo)))
+		return -EFAULT;
+
+	return 0;
+}
+
+#ifdef CONFIG_COMPAT
+struct compat_sysinfo {
+	s32 uptime;
+	u32 loads[3];
+	u32 totalram;
+	u32 freeram;
+	u32 sharedram;
+	u32 bufferram;
+	u32 totalswap;
+	u32 freeswap;
+	u16 procs;
+	u16 pad;
+	u32 totalhigh;
+	u32 freehigh;
+	u32 mem_unit;
+	char _f[20-2*sizeof(u32)-sizeof(int)];
+};
+
+COMPAT_SYSCALL_DEFINE1(sysinfo, struct compat_sysinfo __user *, info)
+{
+	struct sysinfo s;
+	struct compat_sysinfo s_32;
+
+	do_sysinfo(&s);
+
+	/* Check to see if any memory value is too large for 32-bit and scale
+	 *  down if needed
+	 */
+	if (upper_32_bits(s.totalram) || upper_32_bits(s.totalswap)) {
+		int bitcount = 0;
+
+		while (s.mem_unit < PAGE_SIZE) {
+			s.mem_unit <<= 1;
+			bitcount++;
+		}
+
+		s.totalram >>= bitcount;
+		s.freeram >>= bitcount;
+		s.sharedram >>= bitcount;
+		s.bufferram >>= bitcount;
+		s.totalswap >>= bitcount;
+		s.freeswap >>= bitcount;
+		s.totalhigh >>= bitcount;
+		s.freehigh >>= bitcount;
+	}
+
+	memset(&s_32, 0, sizeof(s_32));
+	s_32.uptime = s.uptime;
+	s_32.loads[0] = s.loads[0];
+	s_32.loads[1] = s.loads[1];
+	s_32.loads[2] = s.loads[2];
+	s_32.totalram = s.totalram;
+	s_32.freeram = s.freeram;
+	s_32.sharedram = s.sharedram;
+	s_32.bufferram = s.bufferram;
+	s_32.totalswap = s.totalswap;
+	s_32.freeswap = s.freeswap;
+	s_32.procs = s.procs;
+	s_32.totalhigh = s.totalhigh;
+	s_32.freehigh = s.freehigh;
+	s_32.mem_unit = s.mem_unit;
+	if (copy_to_user(info, &s_32, sizeof(s_32)))
+		return -EFAULT;
+	return 0;
+}
+#endif /* CONFIG_COMPAT */
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
new file mode 100644
index 000000000..860b2dcf3
--- /dev/null
+++ b/kernel/sys_ni.c
@@ -0,0 +1,481 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/linkage.h>
+#include <linux/errno.h>
+
+#include <asm/unistd.h>
+
+#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
+/* Architectures may override COND_SYSCALL and COND_SYSCALL_COMPAT */
+#include <asm/syscall_wrapper.h>
+#endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */
+
+/*  we can't #include <linux/syscalls.h> here,
+    but tell gcc to not warn with -Wmissing-prototypes  */
+asmlinkage long sys_ni_syscall(void);
+
+/*
+ * Non-implemented system calls get redirected here.
+ */
+asmlinkage long sys_ni_syscall(void)
+{
+	return -ENOSYS;
+}
+
+#ifndef COND_SYSCALL
+#define COND_SYSCALL(name) cond_syscall(sys_##name)
+#endif /* COND_SYSCALL */
+
+#ifndef COND_SYSCALL_COMPAT
+#define COND_SYSCALL_COMPAT(name) cond_syscall(compat_sys_##name)
+#endif /* COND_SYSCALL_COMPAT */
+
+/*
+ * This list is kept in the same order as include/uapi/asm-generic/unistd.h.
+ * Architecture specific entries go below, followed by deprecated or obsolete
+ * system calls.
+ */
+
+COND_SYSCALL(io_setup);
+COND_SYSCALL_COMPAT(io_setup);
+COND_SYSCALL(io_destroy);
+COND_SYSCALL(io_submit);
+COND_SYSCALL_COMPAT(io_submit);
+COND_SYSCALL(io_cancel);
+COND_SYSCALL(io_getevents_time32);
+COND_SYSCALL(io_getevents);
+COND_SYSCALL(io_pgetevents_time32);
+COND_SYSCALL(io_pgetevents);
+COND_SYSCALL_COMPAT(io_pgetevents_time32);
+COND_SYSCALL_COMPAT(io_pgetevents);
+COND_SYSCALL(io_uring_setup);
+COND_SYSCALL(io_uring_enter);
+COND_SYSCALL(io_uring_register);
+
+/* fs/xattr.c */
+
+/* fs/dcache.c */
+
+/* fs/cookies.c */
+COND_SYSCALL(lookup_dcookie);
+COND_SYSCALL_COMPAT(lookup_dcookie);
+
+/* fs/eventfd.c */
+COND_SYSCALL(eventfd2);
+
+/* fs/eventfd.c */
+COND_SYSCALL(epoll_create1);
+COND_SYSCALL(epoll_ctl);
+COND_SYSCALL(epoll_pwait);
+COND_SYSCALL_COMPAT(epoll_pwait);
+COND_SYSCALL(epoll_pwait2);
+COND_SYSCALL_COMPAT(epoll_pwait2);
+
+/* fs/fcntl.c */
+
+/* fs/inotify_user.c */
+COND_SYSCALL(inotify_init1);
+COND_SYSCALL(inotify_add_watch);
+COND_SYSCALL(inotify_rm_watch);
+
+/* fs/ioctl.c */
+
+/* fs/ioprio.c */
+COND_SYSCALL(ioprio_set);
+COND_SYSCALL(ioprio_get);
+
+/* fs/locks.c */
+COND_SYSCALL(flock);
+
+/* fs/namei.c */
+
+/* fs/namespace.c */
+
+/* fs/nfsctl.c */
+
+/* fs/open.c */
+
+/* fs/pipe.c */
+
+/* fs/quota.c */
+COND_SYSCALL(quotactl);
+COND_SYSCALL(quotactl_fd);
+
+/* fs/readdir.c */
+
+/* fs/read_write.c */
+
+/* fs/sendfile.c */
+
+/* fs/select.c */
+
+/* fs/signalfd.c */
+COND_SYSCALL(signalfd4);
+COND_SYSCALL_COMPAT(signalfd4);
+
+/* fs/splice.c */
+
+/* fs/stat.c */
+
+/* fs/sync.c */
+
+/* fs/timerfd.c */
+COND_SYSCALL(timerfd_create);
+COND_SYSCALL(timerfd_settime);
+COND_SYSCALL(timerfd_settime32);
+COND_SYSCALL(timerfd_gettime);
+COND_SYSCALL(timerfd_gettime32);
+
+/* fs/utimes.c */
+
+/* kernel/acct.c */
+COND_SYSCALL(acct);
+
+/* kernel/capability.c */
+COND_SYSCALL(capget);
+COND_SYSCALL(capset);
+
+/* kernel/exec_domain.c */
+
+/* kernel/exit.c */
+
+/* kernel/fork.c */
+/* __ARCH_WANT_SYS_CLONE3 */
+COND_SYSCALL(clone3);
+
+/* kernel/futex/syscalls.c */
+COND_SYSCALL(futex);
+COND_SYSCALL(futex_time32);
+COND_SYSCALL(set_robust_list);
+COND_SYSCALL_COMPAT(set_robust_list);
+COND_SYSCALL(get_robust_list);
+COND_SYSCALL_COMPAT(get_robust_list);
+COND_SYSCALL(futex_waitv);
+
+/* kernel/hrtimer.c */
+
+/* kernel/itimer.c */
+
+/* kernel/kexec.c */
+COND_SYSCALL(kexec_load);
+COND_SYSCALL_COMPAT(kexec_load);
+
+/* kernel/module.c */
+COND_SYSCALL(init_module);
+COND_SYSCALL(delete_module);
+
+/* kernel/posix-timers.c */
+
+/* kernel/printk.c */
+COND_SYSCALL(syslog);
+
+/* kernel/ptrace.c */
+
+/* kernel/sched/core.c */
+
+/* kernel/sys.c */
+COND_SYSCALL(setregid);
+COND_SYSCALL(setgid);
+COND_SYSCALL(setreuid);
+COND_SYSCALL(setuid);
+COND_SYSCALL(setresuid);
+COND_SYSCALL(getresuid);
+COND_SYSCALL(setresgid);
+COND_SYSCALL(getresgid);
+COND_SYSCALL(setfsuid);
+COND_SYSCALL(setfsgid);
+COND_SYSCALL(setgroups);
+COND_SYSCALL(getgroups);
+
+/* kernel/time.c */
+
+/* kernel/timer.c */
+
+/* ipc/mqueue.c */
+COND_SYSCALL(mq_open);
+COND_SYSCALL_COMPAT(mq_open);
+COND_SYSCALL(mq_unlink);
+COND_SYSCALL(mq_timedsend);
+COND_SYSCALL(mq_timedsend_time32);
+COND_SYSCALL(mq_timedreceive);
+COND_SYSCALL(mq_timedreceive_time32);
+COND_SYSCALL(mq_notify);
+COND_SYSCALL_COMPAT(mq_notify);
+COND_SYSCALL(mq_getsetattr);
+COND_SYSCALL_COMPAT(mq_getsetattr);
+
+/* ipc/msg.c */
+COND_SYSCALL(msgget);
+COND_SYSCALL(old_msgctl);
+COND_SYSCALL(msgctl);
+COND_SYSCALL_COMPAT(msgctl);
+COND_SYSCALL_COMPAT(old_msgctl);
+COND_SYSCALL(msgrcv);
+COND_SYSCALL_COMPAT(msgrcv);
+COND_SYSCALL(msgsnd);
+COND_SYSCALL_COMPAT(msgsnd);
+
+/* ipc/sem.c */
+COND_SYSCALL(semget);
+COND_SYSCALL(old_semctl);
+COND_SYSCALL(semctl);
+COND_SYSCALL_COMPAT(semctl);
+COND_SYSCALL_COMPAT(old_semctl);
+COND_SYSCALL(semtimedop);
+COND_SYSCALL(semtimedop_time32);
+COND_SYSCALL(semop);
+
+/* ipc/shm.c */
+COND_SYSCALL(shmget);
+COND_SYSCALL(old_shmctl);
+COND_SYSCALL(shmctl);
+COND_SYSCALL_COMPAT(shmctl);
+COND_SYSCALL_COMPAT(old_shmctl);
+COND_SYSCALL(shmat);
+COND_SYSCALL_COMPAT(shmat);
+COND_SYSCALL(shmdt);
+
+/* net/socket.c */
+COND_SYSCALL(socket);
+COND_SYSCALL(socketpair);
+COND_SYSCALL(bind);
+COND_SYSCALL(listen);
+COND_SYSCALL(accept);
+COND_SYSCALL(connect);
+COND_SYSCALL(getsockname);
+COND_SYSCALL(getpeername);
+COND_SYSCALL(setsockopt);
+COND_SYSCALL_COMPAT(setsockopt);
+COND_SYSCALL(getsockopt);
+COND_SYSCALL_COMPAT(getsockopt);
+COND_SYSCALL(sendto);
+COND_SYSCALL(shutdown);
+COND_SYSCALL(recvfrom);
+COND_SYSCALL_COMPAT(recvfrom);
+COND_SYSCALL(sendmsg);
+COND_SYSCALL_COMPAT(sendmsg);
+COND_SYSCALL(recvmsg);
+COND_SYSCALL_COMPAT(recvmsg);
+
+/* mm/filemap.c */
+
+/* mm/nommu.c, also with MMU */
+COND_SYSCALL(mremap);
+
+/* security/keys/keyctl.c */
+COND_SYSCALL(add_key);
+COND_SYSCALL(request_key);
+COND_SYSCALL(keyctl);
+COND_SYSCALL_COMPAT(keyctl);
+
+/* security/landlock/syscalls.c */
+COND_SYSCALL(landlock_create_ruleset);
+COND_SYSCALL(landlock_add_rule);
+COND_SYSCALL(landlock_restrict_self);
+
+/* arch/example/kernel/sys_example.c */
+
+/* mm/fadvise.c */
+COND_SYSCALL(fadvise64_64);
+COND_SYSCALL_COMPAT(fadvise64_64);
+
+/* mm/, CONFIG_MMU only */
+COND_SYSCALL(swapon);
+COND_SYSCALL(swapoff);
+COND_SYSCALL(mprotect);
+COND_SYSCALL(msync);
+COND_SYSCALL(mlock);
+COND_SYSCALL(munlock);
+COND_SYSCALL(mlockall);
+COND_SYSCALL(munlockall);
+COND_SYSCALL(mincore);
+COND_SYSCALL(madvise);
+COND_SYSCALL(process_madvise);
+COND_SYSCALL(process_mrelease);
+COND_SYSCALL(remap_file_pages);
+COND_SYSCALL(mbind);
+COND_SYSCALL(get_mempolicy);
+COND_SYSCALL(set_mempolicy);
+COND_SYSCALL(migrate_pages);
+COND_SYSCALL(move_pages);
+COND_SYSCALL(set_mempolicy_home_node);
+
+COND_SYSCALL(perf_event_open);
+COND_SYSCALL(accept4);
+COND_SYSCALL(recvmmsg);
+COND_SYSCALL(recvmmsg_time32);
+COND_SYSCALL_COMPAT(recvmmsg_time32);
+COND_SYSCALL_COMPAT(recvmmsg_time64);
+
+/*
+ * Architecture specific syscalls: see further below
+ */
+
+/* fanotify */
+COND_SYSCALL(fanotify_init);
+COND_SYSCALL(fanotify_mark);
+
+/* open by handle */
+COND_SYSCALL(name_to_handle_at);
+COND_SYSCALL(open_by_handle_at);
+COND_SYSCALL_COMPAT(open_by_handle_at);
+
+COND_SYSCALL(sendmmsg);
+COND_SYSCALL_COMPAT(sendmmsg);
+COND_SYSCALL(process_vm_readv);
+COND_SYSCALL_COMPAT(process_vm_readv);
+COND_SYSCALL(process_vm_writev);
+COND_SYSCALL_COMPAT(process_vm_writev);
+
+/* compare kernel pointers */
+COND_SYSCALL(kcmp);
+
+COND_SYSCALL(finit_module);
+
+/* operate on Secure Computing state */
+COND_SYSCALL(seccomp);
+
+COND_SYSCALL(memfd_create);
+
+/* access BPF programs and maps */
+COND_SYSCALL(bpf);
+
+/* execveat */
+COND_SYSCALL(execveat);
+
+COND_SYSCALL(userfaultfd);
+
+/* membarrier */
+COND_SYSCALL(membarrier);
+
+COND_SYSCALL(mlock2);
+
+COND_SYSCALL(copy_file_range);
+
+/* memory protection keys */
+COND_SYSCALL(pkey_mprotect);
+COND_SYSCALL(pkey_alloc);
+COND_SYSCALL(pkey_free);
+
+/* memfd_secret */
+COND_SYSCALL(memfd_secret);
+
+/*
+ * Architecture specific weak syscall entries.
+ */
+
+/* pciconfig: alpha, arm, arm64, ia64, sparc */
+COND_SYSCALL(pciconfig_read);
+COND_SYSCALL(pciconfig_write);
+COND_SYSCALL(pciconfig_iobase);
+
+/* sys_socketcall: arm, mips, x86, ... */
+COND_SYSCALL(socketcall);
+COND_SYSCALL_COMPAT(socketcall);
+
+/* compat syscalls for arm64, x86, ... */
+COND_SYSCALL_COMPAT(fanotify_mark);
+
+/* x86 */
+COND_SYSCALL(vm86old);
+COND_SYSCALL(modify_ldt);
+COND_SYSCALL(vm86);
+COND_SYSCALL(kexec_file_load);
+
+/* s390 */
+COND_SYSCALL(s390_pci_mmio_read);
+COND_SYSCALL(s390_pci_mmio_write);
+COND_SYSCALL(s390_ipc);
+COND_SYSCALL_COMPAT(s390_ipc);
+
+/* powerpc */
+COND_SYSCALL(rtas);
+COND_SYSCALL(spu_run);
+COND_SYSCALL(spu_create);
+COND_SYSCALL(subpage_prot);
+
+
+/*
+ * Deprecated system calls which are still defined in
+ * include/uapi/asm-generic/unistd.h and wanted by >= 1 arch
+ */
+
+/* __ARCH_WANT_SYSCALL_NO_FLAGS */
+COND_SYSCALL(epoll_create);
+COND_SYSCALL(inotify_init);
+COND_SYSCALL(eventfd);
+COND_SYSCALL(signalfd);
+COND_SYSCALL_COMPAT(signalfd);
+
+/* __ARCH_WANT_SYSCALL_OFF_T */
+COND_SYSCALL(fadvise64);
+
+/* __ARCH_WANT_SYSCALL_DEPRECATED */
+COND_SYSCALL(epoll_wait);
+COND_SYSCALL(recv);
+COND_SYSCALL_COMPAT(recv);
+COND_SYSCALL(send);
+COND_SYSCALL(uselib);
+
+/* optional: time32 */
+COND_SYSCALL(time32);
+COND_SYSCALL(stime32);
+COND_SYSCALL(utime32);
+COND_SYSCALL(adjtimex_time32);
+COND_SYSCALL(sched_rr_get_interval_time32);
+COND_SYSCALL(nanosleep_time32);
+COND_SYSCALL(rt_sigtimedwait_time32);
+COND_SYSCALL_COMPAT(rt_sigtimedwait_time32);
+COND_SYSCALL(timer_settime32);
+COND_SYSCALL(timer_gettime32);
+COND_SYSCALL(clock_settime32);
+COND_SYSCALL(clock_gettime32);
+COND_SYSCALL(clock_getres_time32);
+COND_SYSCALL(clock_nanosleep_time32);
+COND_SYSCALL(utimes_time32);
+COND_SYSCALL(futimesat_time32);
+COND_SYSCALL(pselect6_time32);
+COND_SYSCALL_COMPAT(pselect6_time32);
+COND_SYSCALL(ppoll_time32);
+COND_SYSCALL_COMPAT(ppoll_time32);
+COND_SYSCALL(utimensat_time32);
+COND_SYSCALL(clock_adjtime32);
+
+/*
+ * The syscalls below are not found in include/uapi/asm-generic/unistd.h
+ */
+
+/* obsolete: SGETMASK_SYSCALL */
+COND_SYSCALL(sgetmask);
+COND_SYSCALL(ssetmask);
+
+/* obsolete: SYSFS_SYSCALL */
+COND_SYSCALL(sysfs);
+
+/* obsolete: __ARCH_WANT_SYS_IPC */
+COND_SYSCALL(ipc);
+COND_SYSCALL_COMPAT(ipc);
+
+/* obsolete: UID16 */
+COND_SYSCALL(chown16);
+COND_SYSCALL(fchown16);
+COND_SYSCALL(getegid16);
+COND_SYSCALL(geteuid16);
+COND_SYSCALL(getgid16);
+COND_SYSCALL(getgroups16);
+COND_SYSCALL(getresgid16);
+COND_SYSCALL(getresuid16);
+COND_SYSCALL(getuid16);
+COND_SYSCALL(lchown16);
+COND_SYSCALL(setfsgid16);
+COND_SYSCALL(setfsuid16);
+COND_SYSCALL(setgid16);
+COND_SYSCALL(setgroups16);
+COND_SYSCALL(setregid16);
+COND_SYSCALL(setresgid16);
+COND_SYSCALL(setresuid16);
+COND_SYSCALL(setreuid16);
+COND_SYSCALL(setuid16);
+
+/* restartable sequence */
+COND_SYSCALL(rseq);
diff --git a/kernel/sysctl-test.c b/kernel/sysctl-test.c
new file mode 100644
index 000000000..6ef887c19
--- /dev/null
+++ b/kernel/sysctl-test.c
@@ -0,0 +1,391 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit test of proc sysctl.
+ */
+
+#include <kunit/test.h>
+#include <linux/sysctl.h>
+
+#define KUNIT_PROC_READ 0
+#define KUNIT_PROC_WRITE 1
+
+/*
+ * Test that proc_dointvec will not try to use a NULL .data field even when the
+ * length is non-zero.
+ */
+static void sysctl_test_api_dointvec_null_tbl_data(struct kunit *test)
+{
+	struct ctl_table null_data_table = {
+		.procname = "foo",
+		/*
+		 * Here we are testing that proc_dointvec behaves correctly when
+		 * we give it a NULL .data field. Normally this would point to a
+		 * piece of memory where the value would be stored.
+		 */
+		.data		= NULL,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE_HUNDRED,
+	};
+	/*
+	 * proc_dointvec expects a buffer in user space, so we allocate one. We
+	 * also need to cast it to __user so sparse doesn't get mad.
+	 */
+	void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
+							   GFP_USER);
+	size_t len;
+	loff_t pos;
+
+	/*
+	 * We don't care what the starting length is since proc_dointvec should
+	 * not try to read because .data is NULL.
+	 */
+	len = 1234;
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
+					       KUNIT_PROC_READ, buffer, &len,
+					       &pos));
+	KUNIT_EXPECT_EQ(test, 0, len);
+
+	/*
+	 * See above.
+	 */
+	len = 1234;
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
+					       KUNIT_PROC_WRITE, buffer, &len,
+					       &pos));
+	KUNIT_EXPECT_EQ(test, 0, len);
+}
+
+/*
+ * Similar to the previous test, we create a struct ctrl_table that has a .data
+ * field that proc_dointvec cannot do anything with; however, this time it is
+ * because we tell proc_dointvec that the size is 0.
+ */
+static void sysctl_test_api_dointvec_table_maxlen_unset(struct kunit *test)
+{
+	int data = 0;
+	struct ctl_table data_maxlen_unset_table = {
+		.procname = "foo",
+		.data		= &data,
+		/*
+		 * So .data is no longer NULL, but we tell proc_dointvec its
+		 * length is 0, so it still shouldn't try to use it.
+		 */
+		.maxlen		= 0,
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE_HUNDRED,
+	};
+	void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
+							   GFP_USER);
+	size_t len;
+	loff_t pos;
+
+	/*
+	 * As before, we don't care what buffer length is because proc_dointvec
+	 * cannot do anything because its internal .data buffer has zero length.
+	 */
+	len = 1234;
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
+					       KUNIT_PROC_READ, buffer, &len,
+					       &pos));
+	KUNIT_EXPECT_EQ(test, 0, len);
+
+	/*
+	 * See previous comment.
+	 */
+	len = 1234;
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
+					       KUNIT_PROC_WRITE, buffer, &len,
+					       &pos));
+	KUNIT_EXPECT_EQ(test, 0, len);
+}
+
+/*
+ * Here we provide a valid struct ctl_table, but we try to read and write from
+ * it using a buffer of zero length, so it should still fail in a similar way as
+ * before.
+ */
+static void sysctl_test_api_dointvec_table_len_is_zero(struct kunit *test)
+{
+	int data = 0;
+	/* Good table. */
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE_HUNDRED,
+	};
+	void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
+							   GFP_USER);
+	/*
+	 * However, now our read/write buffer has zero length.
+	 */
+	size_t len = 0;
+	loff_t pos;
+
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
+					       &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, len);
+
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE, buffer,
+					       &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, len);
+}
+
+/*
+ * Test that proc_dointvec refuses to read when the file position is non-zero.
+ */
+static void sysctl_test_api_dointvec_table_read_but_position_set(
+		struct kunit *test)
+{
+	int data = 0;
+	/* Good table. */
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE_HUNDRED,
+	};
+	void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
+							   GFP_USER);
+	/*
+	 * We don't care about our buffer length because we start off with a
+	 * non-zero file position.
+	 */
+	size_t len = 1234;
+	/*
+	 * proc_dointvec should refuse to read into the buffer since the file
+	 * pos is non-zero.
+	 */
+	loff_t pos = 1;
+
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
+					       &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, len);
+}
+
+/*
+ * Test that we can read a two digit number in a sufficiently size buffer.
+ * Nothing fancy.
+ */
+static void sysctl_test_dointvec_read_happy_single_positive(struct kunit *test)
+{
+	int data = 0;
+	/* Good table. */
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE_HUNDRED,
+	};
+	size_t len = 4;
+	loff_t pos = 0;
+	char *buffer = kunit_kzalloc(test, len, GFP_USER);
+	char __user *user_buffer = (char __user *)buffer;
+	/* Store 13 in the data field. */
+	*((int *)table.data) = 13;
+
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
+					       user_buffer, &len, &pos));
+	KUNIT_ASSERT_EQ(test, 3, len);
+	buffer[len] = '\0';
+	/* And we read 13 back out. */
+	KUNIT_EXPECT_STREQ(test, "13\n", buffer);
+}
+
+/*
+ * Same as previous test, just now with negative numbers.
+ */
+static void sysctl_test_dointvec_read_happy_single_negative(struct kunit *test)
+{
+	int data = 0;
+	/* Good table. */
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE_HUNDRED,
+	};
+	size_t len = 5;
+	loff_t pos = 0;
+	char *buffer = kunit_kzalloc(test, len, GFP_USER);
+	char __user *user_buffer = (char __user *)buffer;
+	*((int *)table.data) = -16;
+
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
+					       user_buffer, &len, &pos));
+	KUNIT_ASSERT_EQ(test, 4, len);
+	buffer[len] = '\0';
+	KUNIT_EXPECT_STREQ(test, "-16\n", buffer);
+}
+
+/*
+ * Test that a simple positive write works.
+ */
+static void sysctl_test_dointvec_write_happy_single_positive(struct kunit *test)
+{
+	int data = 0;
+	/* Good table. */
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE_HUNDRED,
+	};
+	char input[] = "9";
+	size_t len = sizeof(input) - 1;
+	loff_t pos = 0;
+	char *buffer = kunit_kzalloc(test, len, GFP_USER);
+	char __user *user_buffer = (char __user *)buffer;
+
+	memcpy(buffer, input, len);
+
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
+					       user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
+	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, pos);
+	KUNIT_EXPECT_EQ(test, 9, *((int *)table.data));
+}
+
+/*
+ * Same as previous test, but now with negative numbers.
+ */
+static void sysctl_test_dointvec_write_happy_single_negative(struct kunit *test)
+{
+	int data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE_HUNDRED,
+	};
+	char input[] = "-9";
+	size_t len = sizeof(input) - 1;
+	loff_t pos = 0;
+	char *buffer = kunit_kzalloc(test, len, GFP_USER);
+	char __user *user_buffer = (char __user *)buffer;
+
+	memcpy(buffer, input, len);
+
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
+					       user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
+	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, pos);
+	KUNIT_EXPECT_EQ(test, -9, *((int *)table.data));
+}
+
+/*
+ * Test that writing a value smaller than the minimum possible value is not
+ * allowed.
+ */
+static void sysctl_test_api_dointvec_write_single_less_int_min(
+		struct kunit *test)
+{
+	int data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE_HUNDRED,
+	};
+	size_t max_len = 32, len = max_len;
+	loff_t pos = 0;
+	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
+	char __user *user_buffer = (char __user *)buffer;
+	unsigned long abs_of_less_than_min = (unsigned long)INT_MAX
+					     - (INT_MAX + INT_MIN) + 1;
+
+	/*
+	 * We use this rigmarole to create a string that contains a value one
+	 * less than the minimum accepted value.
+	 */
+	KUNIT_ASSERT_LT(test,
+			(size_t)snprintf(buffer, max_len, "-%lu",
+					 abs_of_less_than_min),
+			max_len);
+
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
+						     user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, max_len, len);
+	KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
+}
+
+/*
+ * Test that writing the maximum possible value works.
+ */
+static void sysctl_test_api_dointvec_write_single_greater_int_max(
+		struct kunit *test)
+{
+	int data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE_HUNDRED,
+	};
+	size_t max_len = 32, len = max_len;
+	loff_t pos = 0;
+	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
+	char __user *user_buffer = (char __user *)buffer;
+	unsigned long greater_than_max = (unsigned long)INT_MAX + 1;
+
+	KUNIT_ASSERT_GT(test, greater_than_max, (unsigned long)INT_MAX);
+	KUNIT_ASSERT_LT(test, (size_t)snprintf(buffer, max_len, "%lu",
+					       greater_than_max),
+			max_len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
+						     user_buffer, &len, &pos));
+	KUNIT_ASSERT_EQ(test, max_len, len);
+	KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
+}
+
+static struct kunit_case sysctl_test_cases[] = {
+	KUNIT_CASE(sysctl_test_api_dointvec_null_tbl_data),
+	KUNIT_CASE(sysctl_test_api_dointvec_table_maxlen_unset),
+	KUNIT_CASE(sysctl_test_api_dointvec_table_len_is_zero),
+	KUNIT_CASE(sysctl_test_api_dointvec_table_read_but_position_set),
+	KUNIT_CASE(sysctl_test_dointvec_read_happy_single_positive),
+	KUNIT_CASE(sysctl_test_dointvec_read_happy_single_negative),
+	KUNIT_CASE(sysctl_test_dointvec_write_happy_single_positive),
+	KUNIT_CASE(sysctl_test_dointvec_write_happy_single_negative),
+	KUNIT_CASE(sysctl_test_api_dointvec_write_single_less_int_min),
+	KUNIT_CASE(sysctl_test_api_dointvec_write_single_greater_int_max),
+	{}
+};
+
+static struct kunit_suite sysctl_test_suite = {
+	.name = "sysctl_test",
+	.test_cases = sysctl_test_cases,
+};
+
+kunit_test_suites(&sysctl_test_suite);
+
+MODULE_LICENSE("GPL v2");
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
new file mode 100644
index 000000000..c6d9dec11
--- /dev/null
+++ b/kernel/sysctl.c
@@ -0,0 +1,2516 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sysctl.c: General linux system control interface
+ *
+ * Begun 24 March 1995, Stephen Tweedie
+ * Added /proc support, Dec 1995
+ * Added bdflush entry and intvec min/max checking, 2/23/96, Tom Dyas.
+ * Added hooks for /proc/sys/net (minor, minor patch), 96/4/1, Mike Shaver.
+ * Added kernel/java-{interpreter,appletviewer}, 96/5/10, Mike Shaver.
+ * Dynamic registration fixes, Stephen Tweedie.
+ * Added kswapd-interval, ctrl-alt-del, printk stuff, 1/8/97, Chris Horn.
+ * Made sysctl support optional via CONFIG_SYSCTL, 1/10/97, Chris
+ *  Horn.
+ * Added proc_doulongvec_ms_jiffies_minmax, 09/08/99, Carlos H. Bauer.
+ * Added proc_doulongvec_minmax, 09/08/99, Carlos H. Bauer.
+ * Changed linked lists to use list.h instead of lists.h, 02/24/00, Bill
+ *  Wendling.
+ * The list_for_each() macro wasn't appropriate for the sysctl loop.
+ *  Removed it and replaced it with older style, 03/23/00, Bill Wendling
+ */
+
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/slab.h>
+#include <linux/sysctl.h>
+#include <linux/bitmap.h>
+#include <linux/signal.h>
+#include <linux/panic.h>
+#include <linux/printk.h>
+#include <linux/proc_fs.h>
+#include <linux/security.h>
+#include <linux/ctype.h>
+#include <linux/kmemleak.h>
+#include <linux/filter.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kobject.h>
+#include <linux/net.h>
+#include <linux/sysrq.h>
+#include <linux/highuid.h>
+#include <linux/writeback.h>
+#include <linux/ratelimit.h>
+#include <linux/compaction.h>
+#include <linux/hugetlb.h>
+#include <linux/initrd.h>
+#include <linux/key.h>
+#include <linux/times.h>
+#include <linux/limits.h>
+#include <linux/dcache.h>
+#include <linux/syscalls.h>
+#include <linux/vmstat.h>
+#include <linux/nfs_fs.h>
+#include <linux/acpi.h>
+#include <linux/reboot.h>
+#include <linux/ftrace.h>
+#include <linux/perf_event.h>
+#include <linux/oom.h>
+#include <linux/kmod.h>
+#include <linux/capability.h>
+#include <linux/binfmts.h>
+#include <linux/sched/sysctl.h>
+#include <linux/mount.h>
+#include <linux/userfaultfd_k.h>
+#include <linux/pid.h>
+
+#include "../lib/kstrtox.h"
+
+#include <linux/uaccess.h>
+#include <asm/processor.h>
+
+#ifdef CONFIG_X86
+#include <asm/nmi.h>
+#include <asm/stacktrace.h>
+#include <asm/io.h>
+#endif
+#ifdef CONFIG_SPARC
+#include <asm/setup.h>
+#endif
+#ifdef CONFIG_RT_MUTEXES
+#include <linux/rtmutex.h>
+#endif
+
+/* shared constants to be used in various sysctls */
+const int sysctl_vals[] = { 0, 1, 2, 3, 4, 100, 200, 1000, 3000, INT_MAX, 65535, -1 };
+EXPORT_SYMBOL(sysctl_vals);
+
+const unsigned long sysctl_long_vals[] = { 0, 1, LONG_MAX };
+EXPORT_SYMBOL_GPL(sysctl_long_vals);
+
+#if defined(CONFIG_SYSCTL)
+
+/* Constants used for minimum and maximum */
+
+#ifdef CONFIG_PERF_EVENTS
+static const int six_hundred_forty_kb = 640 * 1024;
+#endif
+
+
+static const int ngroups_max = NGROUPS_MAX;
+static const int cap_last_cap = CAP_LAST_CAP;
+
+#ifdef CONFIG_PROC_SYSCTL
+
+/**
+ * enum sysctl_writes_mode - supported sysctl write modes
+ *
+ * @SYSCTL_WRITES_LEGACY: each write syscall must fully contain the sysctl value
+ *	to be written, and multiple writes on the same sysctl file descriptor
+ *	will rewrite the sysctl value, regardless of file position. No warning
+ *	is issued when the initial position is not 0.
+ * @SYSCTL_WRITES_WARN: same as above but warn when the initial file position is
+ *	not 0.
+ * @SYSCTL_WRITES_STRICT: writes to numeric sysctl entries must always be at
+ *	file position 0 and the value must be fully contained in the buffer
+ *	sent to the write syscall. If dealing with strings respect the file
+ *	position, but restrict this to the max length of the buffer, anything
+ *	passed the max length will be ignored. Multiple writes will append
+ *	to the buffer.
+ *
+ * These write modes control how current file position affects the behavior of
+ * updating sysctl values through the proc interface on each write.
+ */
+enum sysctl_writes_mode {
+	SYSCTL_WRITES_LEGACY		= -1,
+	SYSCTL_WRITES_WARN		= 0,
+	SYSCTL_WRITES_STRICT		= 1,
+};
+
+static enum sysctl_writes_mode sysctl_writes_strict = SYSCTL_WRITES_STRICT;
+#endif /* CONFIG_PROC_SYSCTL */
+
+#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
+    defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
+int sysctl_legacy_va_layout;
+#endif
+
+#endif /* CONFIG_SYSCTL */
+
+/*
+ * /proc/sys support
+ */
+
+#ifdef CONFIG_PROC_SYSCTL
+
+static int _proc_do_string(char *data, int maxlen, int write,
+		char *buffer, size_t *lenp, loff_t *ppos)
+{
+	size_t len;
+	char c, *p;
+
+	if (!data || !maxlen || !*lenp) {
+		*lenp = 0;
+		return 0;
+	}
+
+	if (write) {
+		if (sysctl_writes_strict == SYSCTL_WRITES_STRICT) {
+			/* Only continue writes not past the end of buffer. */
+			len = strlen(data);
+			if (len > maxlen - 1)
+				len = maxlen - 1;
+
+			if (*ppos > len)
+				return 0;
+			len = *ppos;
+		} else {
+			/* Start writing from beginning of buffer. */
+			len = 0;
+		}
+
+		*ppos += *lenp;
+		p = buffer;
+		while ((p - buffer) < *lenp && len < maxlen - 1) {
+			c = *(p++);
+			if (c == 0 || c == '\n')
+				break;
+			data[len++] = c;
+		}
+		data[len] = 0;
+	} else {
+		len = strlen(data);
+		if (len > maxlen)
+			len = maxlen;
+
+		if (*ppos > len) {
+			*lenp = 0;
+			return 0;
+		}
+
+		data += *ppos;
+		len  -= *ppos;
+
+		if (len > *lenp)
+			len = *lenp;
+		if (len)
+			memcpy(buffer, data, len);
+		if (len < *lenp) {
+			buffer[len] = '\n';
+			len++;
+		}
+		*lenp = len;
+		*ppos += len;
+	}
+	return 0;
+}
+
+static void warn_sysctl_write(struct ctl_table *table)
+{
+	pr_warn_once("%s wrote to %s when file position was not 0!\n"
+		"This will not be supported in the future. To silence this\n"
+		"warning, set kernel.sysctl_writes_strict = -1\n",
+		current->comm, table->procname);
+}
+
+/**
+ * proc_first_pos_non_zero_ignore - check if first position is allowed
+ * @ppos: file position
+ * @table: the sysctl table
+ *
+ * Returns true if the first position is non-zero and the sysctl_writes_strict
+ * mode indicates this is not allowed for numeric input types. String proc
+ * handlers can ignore the return value.
+ */
+static bool proc_first_pos_non_zero_ignore(loff_t *ppos,
+					   struct ctl_table *table)
+{
+	if (!*ppos)
+		return false;
+
+	switch (sysctl_writes_strict) {
+	case SYSCTL_WRITES_STRICT:
+		return true;
+	case SYSCTL_WRITES_WARN:
+		warn_sysctl_write(table);
+		return false;
+	default:
+		return false;
+	}
+}
+
+/**
+ * proc_dostring - read a string sysctl
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes a string from/to the user buffer. If the kernel
+ * buffer provided is not large enough to hold the string, the
+ * string is truncated. The copied string is %NULL-terminated.
+ * If the string is being read by the user process, it is copied
+ * and a newline '\n' is added. It is truncated if the buffer is
+ * not large enough.
+ *
+ * Returns 0 on success.
+ */
+int proc_dostring(struct ctl_table *table, int write,
+		  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	if (write)
+		proc_first_pos_non_zero_ignore(ppos, table);
+
+	return _proc_do_string(table->data, table->maxlen, write, buffer, lenp,
+			ppos);
+}
+
+static void proc_skip_spaces(char **buf, size_t *size)
+{
+	while (*size) {
+		if (!isspace(**buf))
+			break;
+		(*size)--;
+		(*buf)++;
+	}
+}
+
+static void proc_skip_char(char **buf, size_t *size, const char v)
+{
+	while (*size) {
+		if (**buf != v)
+			break;
+		(*size)--;
+		(*buf)++;
+	}
+}
+
+/**
+ * strtoul_lenient - parse an ASCII formatted integer from a buffer and only
+ *                   fail on overflow
+ *
+ * @cp: kernel buffer containing the string to parse
+ * @endp: pointer to store the trailing characters
+ * @base: the base to use
+ * @res: where the parsed integer will be stored
+ *
+ * In case of success 0 is returned and @res will contain the parsed integer,
+ * @endp will hold any trailing characters.
+ * This function will fail the parse on overflow. If there wasn't an overflow
+ * the function will defer the decision what characters count as invalid to the
+ * caller.
+ */
+static int strtoul_lenient(const char *cp, char **endp, unsigned int base,
+			   unsigned long *res)
+{
+	unsigned long long result;
+	unsigned int rv;
+
+	cp = _parse_integer_fixup_radix(cp, &base);
+	rv = _parse_integer(cp, base, &result);
+	if ((rv & KSTRTOX_OVERFLOW) || (result != (unsigned long)result))
+		return -ERANGE;
+
+	cp += rv;
+
+	if (endp)
+		*endp = (char *)cp;
+
+	*res = (unsigned long)result;
+	return 0;
+}
+
+#define TMPBUFLEN 22
+/**
+ * proc_get_long - reads an ASCII formatted integer from a user buffer
+ *
+ * @buf: a kernel buffer
+ * @size: size of the kernel buffer
+ * @val: this is where the number will be stored
+ * @neg: set to %TRUE if number is negative
+ * @perm_tr: a vector which contains the allowed trailers
+ * @perm_tr_len: size of the perm_tr vector
+ * @tr: pointer to store the trailer character
+ *
+ * In case of success %0 is returned and @buf and @size are updated with
+ * the amount of bytes read. If @tr is non-NULL and a trailing
+ * character exists (size is non-zero after returning from this
+ * function), @tr is updated with the trailing character.
+ */
+static int proc_get_long(char **buf, size_t *size,
+			  unsigned long *val, bool *neg,
+			  const char *perm_tr, unsigned perm_tr_len, char *tr)
+{
+	char *p, tmp[TMPBUFLEN];
+	ssize_t len = *size;
+
+	if (len <= 0)
+		return -EINVAL;
+
+	if (len > TMPBUFLEN - 1)
+		len = TMPBUFLEN - 1;
+
+	memcpy(tmp, *buf, len);
+
+	tmp[len] = 0;
+	p = tmp;
+	if (*p == '-' && *size > 1) {
+		*neg = true;
+		p++;
+	} else
+		*neg = false;
+	if (!isdigit(*p))
+		return -EINVAL;
+
+	if (strtoul_lenient(p, &p, 0, val))
+		return -EINVAL;
+
+	len = p - tmp;
+
+	/* We don't know if the next char is whitespace thus we may accept
+	 * invalid integers (e.g. 1234...a) or two integers instead of one
+	 * (e.g. 123...1). So lets not allow such large numbers. */
+	if (len == TMPBUFLEN - 1)
+		return -EINVAL;
+
+	if (len < *size && perm_tr_len && !memchr(perm_tr, *p, perm_tr_len))
+		return -EINVAL;
+
+	if (tr && (len < *size))
+		*tr = *p;
+
+	*buf += len;
+	*size -= len;
+
+	return 0;
+}
+
+/**
+ * proc_put_long - converts an integer to a decimal ASCII formatted string
+ *
+ * @buf: the user buffer
+ * @size: the size of the user buffer
+ * @val: the integer to be converted
+ * @neg: sign of the number, %TRUE for negative
+ *
+ * In case of success @buf and @size are updated with the amount of bytes
+ * written.
+ */
+static void proc_put_long(void **buf, size_t *size, unsigned long val, bool neg)
+{
+	int len;
+	char tmp[TMPBUFLEN], *p = tmp;
+
+	sprintf(p, "%s%lu", neg ? "-" : "", val);
+	len = strlen(tmp);
+	if (len > *size)
+		len = *size;
+	memcpy(*buf, tmp, len);
+	*size -= len;
+	*buf += len;
+}
+#undef TMPBUFLEN
+
+static void proc_put_char(void **buf, size_t *size, char c)
+{
+	if (*size) {
+		char **buffer = (char **)buf;
+		**buffer = c;
+
+		(*size)--;
+		(*buffer)++;
+		*buf = *buffer;
+	}
+}
+
+static int do_proc_dobool_conv(bool *negp, unsigned long *lvalp,
+				int *valp,
+				int write, void *data)
+{
+	if (write) {
+		*(bool *)valp = *lvalp;
+	} else {
+		int val = *(bool *)valp;
+
+		*lvalp = (unsigned long)val;
+		*negp = false;
+	}
+	return 0;
+}
+
+static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
+				 int *valp,
+				 int write, void *data)
+{
+	if (write) {
+		if (*negp) {
+			if (*lvalp > (unsigned long) INT_MAX + 1)
+				return -EINVAL;
+			WRITE_ONCE(*valp, -*lvalp);
+		} else {
+			if (*lvalp > (unsigned long) INT_MAX)
+				return -EINVAL;
+			WRITE_ONCE(*valp, *lvalp);
+		}
+	} else {
+		int val = READ_ONCE(*valp);
+		if (val < 0) {
+			*negp = true;
+			*lvalp = -(unsigned long)val;
+		} else {
+			*negp = false;
+			*lvalp = (unsigned long)val;
+		}
+	}
+	return 0;
+}
+
+static int do_proc_douintvec_conv(unsigned long *lvalp,
+				  unsigned int *valp,
+				  int write, void *data)
+{
+	if (write) {
+		if (*lvalp > UINT_MAX)
+			return -EINVAL;
+		WRITE_ONCE(*valp, *lvalp);
+	} else {
+		unsigned int val = READ_ONCE(*valp);
+		*lvalp = (unsigned long)val;
+	}
+	return 0;
+}
+
+static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
+
+static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
+		  int write, void *buffer,
+		  size_t *lenp, loff_t *ppos,
+		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
+			      int write, void *data),
+		  void *data)
+{
+	int *i, vleft, first = 1, err = 0;
+	size_t left;
+	char *p;
+
+	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
+		*lenp = 0;
+		return 0;
+	}
+
+	i = (int *) tbl_data;
+	vleft = table->maxlen / sizeof(*i);
+	left = *lenp;
+
+	if (!conv)
+		conv = do_proc_dointvec_conv;
+
+	if (write) {
+		if (proc_first_pos_non_zero_ignore(ppos, table))
+			goto out;
+
+		if (left > PAGE_SIZE - 1)
+			left = PAGE_SIZE - 1;
+		p = buffer;
+	}
+
+	for (; left && vleft--; i++, first=0) {
+		unsigned long lval;
+		bool neg;
+
+		if (write) {
+			proc_skip_spaces(&p, &left);
+
+			if (!left)
+				break;
+			err = proc_get_long(&p, &left, &lval, &neg,
+					     proc_wspace_sep,
+					     sizeof(proc_wspace_sep), NULL);
+			if (err)
+				break;
+			if (conv(&neg, &lval, i, 1, data)) {
+				err = -EINVAL;
+				break;
+			}
+		} else {
+			if (conv(&neg, &lval, i, 0, data)) {
+				err = -EINVAL;
+				break;
+			}
+			if (!first)
+				proc_put_char(&buffer, &left, '\t');
+			proc_put_long(&buffer, &left, lval, neg);
+		}
+	}
+
+	if (!write && !first && left && !err)
+		proc_put_char(&buffer, &left, '\n');
+	if (write && !err && left)
+		proc_skip_spaces(&p, &left);
+	if (write && first)
+		return err ? : -EINVAL;
+	*lenp -= left;
+out:
+	*ppos += *lenp;
+	return err;
+}
+
+static int do_proc_dointvec(struct ctl_table *table, int write,
+		  void *buffer, size_t *lenp, loff_t *ppos,
+		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
+			      int write, void *data),
+		  void *data)
+{
+	return __do_proc_dointvec(table->data, table, write,
+			buffer, lenp, ppos, conv, data);
+}
+
+static int do_proc_douintvec_w(unsigned int *tbl_data,
+			       struct ctl_table *table,
+			       void *buffer,
+			       size_t *lenp, loff_t *ppos,
+			       int (*conv)(unsigned long *lvalp,
+					   unsigned int *valp,
+					   int write, void *data),
+			       void *data)
+{
+	unsigned long lval;
+	int err = 0;
+	size_t left;
+	bool neg;
+	char *p = buffer;
+
+	left = *lenp;
+
+	if (proc_first_pos_non_zero_ignore(ppos, table))
+		goto bail_early;
+
+	if (left > PAGE_SIZE - 1)
+		left = PAGE_SIZE - 1;
+
+	proc_skip_spaces(&p, &left);
+	if (!left) {
+		err = -EINVAL;
+		goto out_free;
+	}
+
+	err = proc_get_long(&p, &left, &lval, &neg,
+			     proc_wspace_sep,
+			     sizeof(proc_wspace_sep), NULL);
+	if (err || neg) {
+		err = -EINVAL;
+		goto out_free;
+	}
+
+	if (conv(&lval, tbl_data, 1, data)) {
+		err = -EINVAL;
+		goto out_free;
+	}
+
+	if (!err && left)
+		proc_skip_spaces(&p, &left);
+
+out_free:
+	if (err)
+		return -EINVAL;
+
+	return 0;
+
+	/* This is in keeping with old __do_proc_dointvec() */
+bail_early:
+	*ppos += *lenp;
+	return err;
+}
+
+static int do_proc_douintvec_r(unsigned int *tbl_data, void *buffer,
+			       size_t *lenp, loff_t *ppos,
+			       int (*conv)(unsigned long *lvalp,
+					   unsigned int *valp,
+					   int write, void *data),
+			       void *data)
+{
+	unsigned long lval;
+	int err = 0;
+	size_t left;
+
+	left = *lenp;
+
+	if (conv(&lval, tbl_data, 0, data)) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	proc_put_long(&buffer, &left, lval, false);
+	if (!left)
+		goto out;
+
+	proc_put_char(&buffer, &left, '\n');
+
+out:
+	*lenp -= left;
+	*ppos += *lenp;
+
+	return err;
+}
+
+static int __do_proc_douintvec(void *tbl_data, struct ctl_table *table,
+			       int write, void *buffer,
+			       size_t *lenp, loff_t *ppos,
+			       int (*conv)(unsigned long *lvalp,
+					   unsigned int *valp,
+					   int write, void *data),
+			       void *data)
+{
+	unsigned int *i, vleft;
+
+	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
+		*lenp = 0;
+		return 0;
+	}
+
+	i = (unsigned int *) tbl_data;
+	vleft = table->maxlen / sizeof(*i);
+
+	/*
+	 * Arrays are not supported, keep this simple. *Do not* add
+	 * support for them.
+	 */
+	if (vleft != 1) {
+		*lenp = 0;
+		return -EINVAL;
+	}
+
+	if (!conv)
+		conv = do_proc_douintvec_conv;
+
+	if (write)
+		return do_proc_douintvec_w(i, table, buffer, lenp, ppos,
+					   conv, data);
+	return do_proc_douintvec_r(i, buffer, lenp, ppos, conv, data);
+}
+
+int do_proc_douintvec(struct ctl_table *table, int write,
+		      void *buffer, size_t *lenp, loff_t *ppos,
+		      int (*conv)(unsigned long *lvalp,
+				  unsigned int *valp,
+				  int write, void *data),
+		      void *data)
+{
+	return __do_proc_douintvec(table->data, table, write,
+				   buffer, lenp, ppos, conv, data);
+}
+
+/**
+ * proc_dobool - read/write a bool
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
+ * values from/to the user buffer, treated as an ASCII string.
+ *
+ * Returns 0 on success.
+ */
+int proc_dobool(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	return do_proc_dointvec(table, write, buffer, lenp, ppos,
+				do_proc_dobool_conv, NULL);
+}
+
+/**
+ * proc_dointvec - read a vector of integers
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
+ * values from/to the user buffer, treated as an ASCII string.
+ *
+ * Returns 0 on success.
+ */
+int proc_dointvec(struct ctl_table *table, int write, void *buffer,
+		  size_t *lenp, loff_t *ppos)
+{
+	return do_proc_dointvec(table, write, buffer, lenp, ppos, NULL, NULL);
+}
+
+#ifdef CONFIG_COMPACTION
+static int proc_dointvec_minmax_warn_RT_change(struct ctl_table *table,
+		int write, void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int ret, old;
+
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT) || !write)
+		return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+
+	old = *(int *)table->data;
+	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+	if (ret)
+		return ret;
+	if (old != *(int *)table->data)
+		pr_warn_once("sysctl attribute %s changed by %s[%d]\n",
+			     table->procname, current->comm,
+			     task_pid_nr(current));
+	return ret;
+}
+#endif
+
+/**
+ * proc_douintvec - read a vector of unsigned integers
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer
+ * values from/to the user buffer, treated as an ASCII string.
+ *
+ * Returns 0 on success.
+ */
+int proc_douintvec(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	return do_proc_douintvec(table, write, buffer, lenp, ppos,
+				 do_proc_douintvec_conv, NULL);
+}
+
+/*
+ * Taint values can only be increased
+ * This means we can safely use a temporary.
+ */
+static int proc_taint(struct ctl_table *table, int write,
+			       void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table t;
+	unsigned long tmptaint = get_taint();
+	int err;
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	t = *table;
+	t.data = &tmptaint;
+	err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
+	if (err < 0)
+		return err;
+
+	if (write) {
+		int i;
+
+		/*
+		 * If we are relying on panic_on_taint not producing
+		 * false positives due to userspace input, bail out
+		 * before setting the requested taint flags.
+		 */
+		if (panic_on_taint_nousertaint && (tmptaint & panic_on_taint))
+			return -EINVAL;
+
+		/*
+		 * Poor man's atomic or. Not worth adding a primitive
+		 * to everyone's atomic.h for this
+		 */
+		for (i = 0; i < TAINT_FLAGS_COUNT; i++)
+			if ((1UL << i) & tmptaint)
+				add_taint(i, LOCKDEP_STILL_OK);
+	}
+
+	return err;
+}
+
+/**
+ * struct do_proc_dointvec_minmax_conv_param - proc_dointvec_minmax() range checking structure
+ * @min: pointer to minimum allowable value
+ * @max: pointer to maximum allowable value
+ *
+ * The do_proc_dointvec_minmax_conv_param structure provides the
+ * minimum and maximum values for doing range checking for those sysctl
+ * parameters that use the proc_dointvec_minmax() handler.
+ */
+struct do_proc_dointvec_minmax_conv_param {
+	int *min;
+	int *max;
+};
+
+static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
+					int *valp,
+					int write, void *data)
+{
+	int tmp, ret;
+	struct do_proc_dointvec_minmax_conv_param *param = data;
+	/*
+	 * If writing, first do so via a temporary local int so we can
+	 * bounds-check it before touching *valp.
+	 */
+	int *ip = write ? &tmp : valp;
+
+	ret = do_proc_dointvec_conv(negp, lvalp, ip, write, data);
+	if (ret)
+		return ret;
+
+	if (write) {
+		if ((param->min && *param->min > tmp) ||
+		    (param->max && *param->max < tmp))
+			return -EINVAL;
+		WRITE_ONCE(*valp, tmp);
+	}
+
+	return 0;
+}
+
+/**
+ * proc_dointvec_minmax - read a vector of integers with min/max values
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
+ * values from/to the user buffer, treated as an ASCII string.
+ *
+ * This routine will ensure the values are within the range specified by
+ * table->extra1 (min) and table->extra2 (max).
+ *
+ * Returns 0 on success or -EINVAL on write when the range check fails.
+ */
+int proc_dointvec_minmax(struct ctl_table *table, int write,
+		  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct do_proc_dointvec_minmax_conv_param param = {
+		.min = (int *) table->extra1,
+		.max = (int *) table->extra2,
+	};
+	return do_proc_dointvec(table, write, buffer, lenp, ppos,
+				do_proc_dointvec_minmax_conv, &param);
+}
+
+/**
+ * struct do_proc_douintvec_minmax_conv_param - proc_douintvec_minmax() range checking structure
+ * @min: pointer to minimum allowable value
+ * @max: pointer to maximum allowable value
+ *
+ * The do_proc_douintvec_minmax_conv_param structure provides the
+ * minimum and maximum values for doing range checking for those sysctl
+ * parameters that use the proc_douintvec_minmax() handler.
+ */
+struct do_proc_douintvec_minmax_conv_param {
+	unsigned int *min;
+	unsigned int *max;
+};
+
+static int do_proc_douintvec_minmax_conv(unsigned long *lvalp,
+					 unsigned int *valp,
+					 int write, void *data)
+{
+	int ret;
+	unsigned int tmp;
+	struct do_proc_douintvec_minmax_conv_param *param = data;
+	/* write via temporary local uint for bounds-checking */
+	unsigned int *up = write ? &tmp : valp;
+
+	ret = do_proc_douintvec_conv(lvalp, up, write, data);
+	if (ret)
+		return ret;
+
+	if (write) {
+		if ((param->min && *param->min > tmp) ||
+		    (param->max && *param->max < tmp))
+			return -ERANGE;
+
+		WRITE_ONCE(*valp, tmp);
+	}
+
+	return 0;
+}
+
+/**
+ * proc_douintvec_minmax - read a vector of unsigned ints with min/max values
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer
+ * values from/to the user buffer, treated as an ASCII string. Negative
+ * strings are not allowed.
+ *
+ * This routine will ensure the values are within the range specified by
+ * table->extra1 (min) and table->extra2 (max). There is a final sanity
+ * check for UINT_MAX to avoid having to support wrap around uses from
+ * userspace.
+ *
+ * Returns 0 on success or -ERANGE on write when the range check fails.
+ */
+int proc_douintvec_minmax(struct ctl_table *table, int write,
+			  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct do_proc_douintvec_minmax_conv_param param = {
+		.min = (unsigned int *) table->extra1,
+		.max = (unsigned int *) table->extra2,
+	};
+	return do_proc_douintvec(table, write, buffer, lenp, ppos,
+				 do_proc_douintvec_minmax_conv, &param);
+}
+
+/**
+ * proc_dou8vec_minmax - read a vector of unsigned chars with min/max values
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(u8) unsigned chars
+ * values from/to the user buffer, treated as an ASCII string. Negative
+ * strings are not allowed.
+ *
+ * This routine will ensure the values are within the range specified by
+ * table->extra1 (min) and table->extra2 (max).
+ *
+ * Returns 0 on success or an error on write when the range check fails.
+ */
+int proc_dou8vec_minmax(struct ctl_table *table, int write,
+			void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table tmp;
+	unsigned int min = 0, max = 255U, val;
+	u8 *data = table->data;
+	struct do_proc_douintvec_minmax_conv_param param = {
+		.min = &min,
+		.max = &max,
+	};
+	int res;
+
+	/* Do not support arrays yet. */
+	if (table->maxlen != sizeof(u8))
+		return -EINVAL;
+
+	if (table->extra1) {
+		min = *(unsigned int *) table->extra1;
+		if (min > 255U)
+			return -EINVAL;
+	}
+	if (table->extra2) {
+		max = *(unsigned int *) table->extra2;
+		if (max > 255U)
+			return -EINVAL;
+	}
+
+	tmp = *table;
+
+	tmp.maxlen = sizeof(val);
+	tmp.data = &val;
+	val = READ_ONCE(*data);
+	res = do_proc_douintvec(&tmp, write, buffer, lenp, ppos,
+				do_proc_douintvec_minmax_conv, &param);
+	if (res)
+		return res;
+	if (write)
+		WRITE_ONCE(*data, val);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(proc_dou8vec_minmax);
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static int sysrq_sysctl_handler(struct ctl_table *table, int write,
+				void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int tmp, ret;
+
+	tmp = sysrq_mask();
+
+	ret = __do_proc_dointvec(&tmp, table, write, buffer,
+			       lenp, ppos, NULL, NULL);
+	if (ret || !write)
+		return ret;
+
+	if (write)
+		sysrq_toggle_support(tmp);
+
+	return 0;
+}
+#endif
+
+static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table,
+		int write, void *buffer, size_t *lenp, loff_t *ppos,
+		unsigned long convmul, unsigned long convdiv)
+{
+	unsigned long *i, *min, *max;
+	int vleft, first = 1, err = 0;
+	size_t left;
+	char *p;
+
+	if (!data || !table->maxlen || !*lenp || (*ppos && !write)) {
+		*lenp = 0;
+		return 0;
+	}
+
+	i = data;
+	min = table->extra1;
+	max = table->extra2;
+	vleft = table->maxlen / sizeof(unsigned long);
+	left = *lenp;
+
+	if (write) {
+		if (proc_first_pos_non_zero_ignore(ppos, table))
+			goto out;
+
+		if (left > PAGE_SIZE - 1)
+			left = PAGE_SIZE - 1;
+		p = buffer;
+	}
+
+	for (; left && vleft--; i++, first = 0) {
+		unsigned long val;
+
+		if (write) {
+			bool neg;
+
+			proc_skip_spaces(&p, &left);
+			if (!left)
+				break;
+
+			err = proc_get_long(&p, &left, &val, &neg,
+					     proc_wspace_sep,
+					     sizeof(proc_wspace_sep), NULL);
+			if (err || neg) {
+				err = -EINVAL;
+				break;
+			}
+
+			val = convmul * val / convdiv;
+			if ((min && val < *min) || (max && val > *max)) {
+				err = -EINVAL;
+				break;
+			}
+			WRITE_ONCE(*i, val);
+		} else {
+			val = convdiv * READ_ONCE(*i) / convmul;
+			if (!first)
+				proc_put_char(&buffer, &left, '\t');
+			proc_put_long(&buffer, &left, val, false);
+		}
+	}
+
+	if (!write && !first && left && !err)
+		proc_put_char(&buffer, &left, '\n');
+	if (write && !err)
+		proc_skip_spaces(&p, &left);
+	if (write && first)
+		return err ? : -EINVAL;
+	*lenp -= left;
+out:
+	*ppos += *lenp;
+	return err;
+}
+
+static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos, unsigned long convmul,
+		unsigned long convdiv)
+{
+	return __do_proc_doulongvec_minmax(table->data, table, write,
+			buffer, lenp, ppos, convmul, convdiv);
+}
+
+/**
+ * proc_doulongvec_minmax - read a vector of long integers with min/max values
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
+ * values from/to the user buffer, treated as an ASCII string.
+ *
+ * This routine will ensure the values are within the range specified by
+ * table->extra1 (min) and table->extra2 (max).
+ *
+ * Returns 0 on success.
+ */
+int proc_doulongvec_minmax(struct ctl_table *table, int write,
+			   void *buffer, size_t *lenp, loff_t *ppos)
+{
+    return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, 1l, 1l);
+}
+
+/**
+ * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
+ * values from/to the user buffer, treated as an ASCII string. The values
+ * are treated as milliseconds, and converted to jiffies when they are stored.
+ *
+ * This routine will ensure the values are within the range specified by
+ * table->extra1 (min) and table->extra2 (max).
+ *
+ * Returns 0 on success.
+ */
+int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
+				      void *buffer, size_t *lenp, loff_t *ppos)
+{
+    return do_proc_doulongvec_minmax(table, write, buffer,
+				     lenp, ppos, HZ, 1000l);
+}
+
+
+static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
+					 int *valp,
+					 int write, void *data)
+{
+	if (write) {
+		if (*lvalp > INT_MAX / HZ)
+			return 1;
+		if (*negp)
+			WRITE_ONCE(*valp, -*lvalp * HZ);
+		else
+			WRITE_ONCE(*valp, *lvalp * HZ);
+	} else {
+		int val = READ_ONCE(*valp);
+		unsigned long lval;
+		if (val < 0) {
+			*negp = true;
+			lval = -(unsigned long)val;
+		} else {
+			*negp = false;
+			lval = (unsigned long)val;
+		}
+		*lvalp = lval / HZ;
+	}
+	return 0;
+}
+
+static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp,
+						int *valp,
+						int write, void *data)
+{
+	if (write) {
+		if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
+			return 1;
+		*valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
+	} else {
+		int val = *valp;
+		unsigned long lval;
+		if (val < 0) {
+			*negp = true;
+			lval = -(unsigned long)val;
+		} else {
+			*negp = false;
+			lval = (unsigned long)val;
+		}
+		*lvalp = jiffies_to_clock_t(lval);
+	}
+	return 0;
+}
+
+static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
+					    int *valp,
+					    int write, void *data)
+{
+	if (write) {
+		unsigned long jif = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
+
+		if (jif > INT_MAX)
+			return 1;
+		WRITE_ONCE(*valp, (int)jif);
+	} else {
+		int val = READ_ONCE(*valp);
+		unsigned long lval;
+		if (val < 0) {
+			*negp = true;
+			lval = -(unsigned long)val;
+		} else {
+			*negp = false;
+			lval = (unsigned long)val;
+		}
+		*lvalp = jiffies_to_msecs(lval);
+	}
+	return 0;
+}
+
+static int do_proc_dointvec_ms_jiffies_minmax_conv(bool *negp, unsigned long *lvalp,
+						int *valp, int write, void *data)
+{
+	int tmp, ret;
+	struct do_proc_dointvec_minmax_conv_param *param = data;
+	/*
+	 * If writing, first do so via a temporary local int so we can
+	 * bounds-check it before touching *valp.
+	 */
+	int *ip = write ? &tmp : valp;
+
+	ret = do_proc_dointvec_ms_jiffies_conv(negp, lvalp, ip, write, data);
+	if (ret)
+		return ret;
+
+	if (write) {
+		if ((param->min && *param->min > tmp) ||
+				(param->max && *param->max < tmp))
+			return -EINVAL;
+		*valp = tmp;
+	}
+	return 0;
+}
+
+/**
+ * proc_dointvec_jiffies - read a vector of integers as seconds
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
+ * values from/to the user buffer, treated as an ASCII string.
+ * The values read are assumed to be in seconds, and are converted into
+ * jiffies.
+ *
+ * Returns 0 on success.
+ */
+int proc_dointvec_jiffies(struct ctl_table *table, int write,
+			  void *buffer, size_t *lenp, loff_t *ppos)
+{
+    return do_proc_dointvec(table,write,buffer,lenp,ppos,
+		    	    do_proc_dointvec_jiffies_conv,NULL);
+}
+
+int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
+			  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct do_proc_dointvec_minmax_conv_param param = {
+		.min = (int *) table->extra1,
+		.max = (int *) table->extra2,
+	};
+	return do_proc_dointvec(table, write, buffer, lenp, ppos,
+			do_proc_dointvec_ms_jiffies_minmax_conv, &param);
+}
+
+/**
+ * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: pointer to the file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
+ * values from/to the user buffer, treated as an ASCII string.
+ * The values read are assumed to be in 1/USER_HZ seconds, and
+ * are converted into jiffies.
+ *
+ * Returns 0 on success.
+ */
+int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
+				 void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return do_proc_dointvec(table, write, buffer, lenp, ppos,
+				do_proc_dointvec_userhz_jiffies_conv, NULL);
+}
+
+/**
+ * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ * @ppos: the current position in the file
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
+ * values from/to the user buffer, treated as an ASCII string.
+ * The values read are assumed to be in 1/1000 seconds, and
+ * are converted into jiffies.
+ *
+ * Returns 0 on success.
+ */
+int proc_dointvec_ms_jiffies(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	return do_proc_dointvec(table, write, buffer, lenp, ppos,
+				do_proc_dointvec_ms_jiffies_conv, NULL);
+}
+
+static int proc_do_cad_pid(struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	struct pid *new_pid;
+	pid_t tmp;
+	int r;
+
+	tmp = pid_vnr(cad_pid);
+
+	r = __do_proc_dointvec(&tmp, table, write, buffer,
+			       lenp, ppos, NULL, NULL);
+	if (r || !write)
+		return r;
+
+	new_pid = find_get_pid(tmp);
+	if (!new_pid)
+		return -ESRCH;
+
+	put_pid(xchg(&cad_pid, new_pid));
+	return 0;
+}
+
+/**
+ * proc_do_large_bitmap - read/write from/to a large bitmap
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * The bitmap is stored at table->data and the bitmap length (in bits)
+ * in table->maxlen.
+ *
+ * We use a range comma separated format (e.g. 1,3-4,10-10) so that
+ * large bitmaps may be represented in a compact manner. Writing into
+ * the file will clear the bitmap then update it with the given input.
+ *
+ * Returns 0 on success.
+ */
+int proc_do_large_bitmap(struct ctl_table *table, int write,
+			 void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int err = 0;
+	size_t left = *lenp;
+	unsigned long bitmap_len = table->maxlen;
+	unsigned long *bitmap = *(unsigned long **) table->data;
+	unsigned long *tmp_bitmap = NULL;
+	char tr_a[] = { '-', ',', '\n' }, tr_b[] = { ',', '\n', 0 }, c;
+
+	if (!bitmap || !bitmap_len || !left || (*ppos && !write)) {
+		*lenp = 0;
+		return 0;
+	}
+
+	if (write) {
+		char *p = buffer;
+		size_t skipped = 0;
+
+		if (left > PAGE_SIZE - 1) {
+			left = PAGE_SIZE - 1;
+			/* How much of the buffer we'll skip this pass */
+			skipped = *lenp - left;
+		}
+
+		tmp_bitmap = bitmap_zalloc(bitmap_len, GFP_KERNEL);
+		if (!tmp_bitmap)
+			return -ENOMEM;
+		proc_skip_char(&p, &left, '\n');
+		while (!err && left) {
+			unsigned long val_a, val_b;
+			bool neg;
+			size_t saved_left;
+
+			/* In case we stop parsing mid-number, we can reset */
+			saved_left = left;
+			err = proc_get_long(&p, &left, &val_a, &neg, tr_a,
+					     sizeof(tr_a), &c);
+			/*
+			 * If we consumed the entirety of a truncated buffer or
+			 * only one char is left (may be a "-"), then stop here,
+			 * reset, & come back for more.
+			 */
+			if ((left <= 1) && skipped) {
+				left = saved_left;
+				break;
+			}
+
+			if (err)
+				break;
+			if (val_a >= bitmap_len || neg) {
+				err = -EINVAL;
+				break;
+			}
+
+			val_b = val_a;
+			if (left) {
+				p++;
+				left--;
+			}
+
+			if (c == '-') {
+				err = proc_get_long(&p, &left, &val_b,
+						     &neg, tr_b, sizeof(tr_b),
+						     &c);
+				/*
+				 * If we consumed all of a truncated buffer or
+				 * then stop here, reset, & come back for more.
+				 */
+				if (!left && skipped) {
+					left = saved_left;
+					break;
+				}
+
+				if (err)
+					break;
+				if (val_b >= bitmap_len || neg ||
+				    val_a > val_b) {
+					err = -EINVAL;
+					break;
+				}
+				if (left) {
+					p++;
+					left--;
+				}
+			}
+
+			bitmap_set(tmp_bitmap, val_a, val_b - val_a + 1);
+			proc_skip_char(&p, &left, '\n');
+		}
+		left += skipped;
+	} else {
+		unsigned long bit_a, bit_b = 0;
+		bool first = 1;
+
+		while (left) {
+			bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
+			if (bit_a >= bitmap_len)
+				break;
+			bit_b = find_next_zero_bit(bitmap, bitmap_len,
+						   bit_a + 1) - 1;
+
+			if (!first)
+				proc_put_char(&buffer, &left, ',');
+			proc_put_long(&buffer, &left, bit_a, false);
+			if (bit_a != bit_b) {
+				proc_put_char(&buffer, &left, '-');
+				proc_put_long(&buffer, &left, bit_b, false);
+			}
+
+			first = 0; bit_b++;
+		}
+		proc_put_char(&buffer, &left, '\n');
+	}
+
+	if (!err) {
+		if (write) {
+			if (*ppos)
+				bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len);
+			else
+				bitmap_copy(bitmap, tmp_bitmap, bitmap_len);
+		}
+		*lenp -= left;
+		*ppos += *lenp;
+	}
+
+	bitmap_free(tmp_bitmap);
+	return err;
+}
+
+#else /* CONFIG_PROC_SYSCTL */
+
+int proc_dostring(struct ctl_table *table, int write,
+		  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_dobool(struct ctl_table *table, int write,
+		void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_dointvec(struct ctl_table *table, int write,
+		  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_douintvec(struct ctl_table *table, int write,
+		  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_dointvec_minmax(struct ctl_table *table, int write,
+		    void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_douintvec_minmax(struct ctl_table *table, int write,
+			  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_dou8vec_minmax(struct ctl_table *table, int write,
+			void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_dointvec_jiffies(struct ctl_table *table, int write,
+		    void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
+				    void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
+		    void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
+			     void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_doulongvec_minmax(struct ctl_table *table, int write,
+		    void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
+				      void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+int proc_do_large_bitmap(struct ctl_table *table, int write,
+			 void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+#endif /* CONFIG_PROC_SYSCTL */
+
+#if defined(CONFIG_SYSCTL)
+int proc_do_static_key(struct ctl_table *table, int write,
+		       void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct static_key *key = (struct static_key *)table->data;
+	static DEFINE_MUTEX(static_key_mutex);
+	int val, ret;
+	struct ctl_table tmp = {
+		.data   = &val,
+		.maxlen = sizeof(val),
+		.mode   = table->mode,
+		.extra1 = SYSCTL_ZERO,
+		.extra2 = SYSCTL_ONE,
+	};
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	mutex_lock(&static_key_mutex);
+	val = static_key_enabled(key);
+	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+	if (write && !ret) {
+		if (val)
+			static_key_enable(key);
+		else
+			static_key_disable(key);
+	}
+	mutex_unlock(&static_key_mutex);
+	return ret;
+}
+
+static struct ctl_table kern_table[] = {
+#ifdef CONFIG_NUMA_BALANCING
+	{
+		.procname	= "numa_balancing",
+		.data		= NULL, /* filled in by handler */
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= sysctl_numa_balancing,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_FOUR,
+	},
+	{
+		.procname	= "numa_balancing_promote_rate_limit_MBps",
+		.data		= &sysctl_numa_balancing_promote_rate_limit,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+#endif /* CONFIG_NUMA_BALANCING */
+	{
+		.procname	= "panic",
+		.data		= &panic_timeout,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#ifdef CONFIG_PROC_SYSCTL
+	{
+		.procname	= "tainted",
+		.maxlen 	= sizeof(long),
+		.mode		= 0644,
+		.proc_handler	= proc_taint,
+	},
+	{
+		.procname	= "sysctl_writes_strict",
+		.data		= &sysctl_writes_strict,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_NEG_ONE,
+		.extra2		= SYSCTL_ONE,
+	},
+#endif
+	{
+		.procname	= "print-fatal-signals",
+		.data		= &print_fatal_signals,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#ifdef CONFIG_SPARC
+	{
+		.procname	= "reboot-cmd",
+		.data		= reboot_command,
+		.maxlen		= 256,
+		.mode		= 0644,
+		.proc_handler	= proc_dostring,
+	},
+	{
+		.procname	= "stop-a",
+		.data		= &stop_a_enabled,
+		.maxlen		= sizeof (int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "scons-poweroff",
+		.data		= &scons_pwroff,
+		.maxlen		= sizeof (int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+#ifdef CONFIG_SPARC64
+	{
+		.procname	= "tsb-ratio",
+		.data		= &sysctl_tsb_ratio,
+		.maxlen		= sizeof (int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+#ifdef CONFIG_PARISC
+	{
+		.procname	= "soft-power",
+		.data		= &pwrsw_enabled,
+		.maxlen		= sizeof (int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+#ifdef CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW
+	{
+		.procname	= "unaligned-trap",
+		.data		= &unaligned_enabled,
+		.maxlen		= sizeof (int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+#ifdef CONFIG_STACK_TRACER
+	{
+		.procname	= "stack_tracer_enabled",
+		.data		= &stack_tracer_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= stack_trace_sysctl,
+	},
+#endif
+#ifdef CONFIG_TRACING
+	{
+		.procname	= "ftrace_dump_on_oops",
+		.data		= &ftrace_dump_on_oops,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "traceoff_on_warning",
+		.data		= &__disable_trace_on_warning,
+		.maxlen		= sizeof(__disable_trace_on_warning),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "tracepoint_printk",
+		.data		= &tracepoint_printk,
+		.maxlen		= sizeof(tracepoint_printk),
+		.mode		= 0644,
+		.proc_handler	= tracepoint_printk_sysctl,
+	},
+#endif
+#ifdef CONFIG_MODULES
+	{
+		.procname	= "modprobe",
+		.data		= &modprobe_path,
+		.maxlen		= KMOD_PATH_LEN,
+		.mode		= 0644,
+		.proc_handler	= proc_dostring,
+	},
+	{
+		.procname	= "modules_disabled",
+		.data		= &modules_disabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		/* only handle a transition from default "0" to "1" */
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_ONE,
+	},
+#endif
+#ifdef CONFIG_UEVENT_HELPER
+	{
+		.procname	= "hotplug",
+		.data		= &uevent_helper,
+		.maxlen		= UEVENT_HELPER_PATH_LEN,
+		.mode		= 0644,
+		.proc_handler	= proc_dostring,
+	},
+#endif
+#ifdef CONFIG_MAGIC_SYSRQ
+	{
+		.procname	= "sysrq",
+		.data		= NULL,
+		.maxlen		= sizeof (int),
+		.mode		= 0644,
+		.proc_handler	= sysrq_sysctl_handler,
+	},
+#endif
+#ifdef CONFIG_PROC_SYSCTL
+	{
+		.procname	= "cad_pid",
+		.data		= NULL,
+		.maxlen		= sizeof (int),
+		.mode		= 0600,
+		.proc_handler	= proc_do_cad_pid,
+	},
+#endif
+	{
+		.procname	= "threads-max",
+		.data		= NULL,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= sysctl_max_threads,
+	},
+	{
+		.procname	= "usermodehelper",
+		.mode		= 0555,
+		.child		= usermodehelper_table,
+	},
+	{
+		.procname	= "overflowuid",
+		.data		= &overflowuid,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_MAXOLDUID,
+	},
+	{
+		.procname	= "overflowgid",
+		.data		= &overflowgid,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_MAXOLDUID,
+	},
+#ifdef CONFIG_S390
+	{
+		.procname	= "userprocess_debug",
+		.data		= &show_unhandled_signals,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+	{
+		.procname	= "pid_max",
+		.data		= &pid_max,
+		.maxlen		= sizeof (int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &pid_max_min,
+		.extra2		= &pid_max_max,
+	},
+	{
+		.procname	= "panic_on_oops",
+		.data		= &panic_on_oops,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "panic_print",
+		.data		= &panic_print,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_minmax,
+	},
+	{
+		.procname	= "ngroups_max",
+		.data		= (void *)&ngroups_max,
+		.maxlen		= sizeof (int),
+		.mode		= 0444,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "cap_last_cap",
+		.data		= (void *)&cap_last_cap,
+		.maxlen		= sizeof(int),
+		.mode		= 0444,
+		.proc_handler	= proc_dointvec,
+	},
+#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
+	{
+		.procname       = "unknown_nmi_panic",
+		.data           = &unknown_nmi_panic,
+		.maxlen         = sizeof (int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec,
+	},
+#endif
+
+#if (defined(CONFIG_X86_32) || defined(CONFIG_PARISC)) && \
+	defined(CONFIG_DEBUG_STACKOVERFLOW)
+	{
+		.procname	= "panic_on_stackoverflow",
+		.data		= &sysctl_panic_on_stackoverflow,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+#if defined(CONFIG_X86)
+	{
+		.procname	= "panic_on_unrecovered_nmi",
+		.data		= &panic_on_unrecovered_nmi,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "panic_on_io_nmi",
+		.data		= &panic_on_io_nmi,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "bootloader_type",
+		.data		= &bootloader_type,
+		.maxlen		= sizeof (int),
+		.mode		= 0444,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "bootloader_version",
+		.data		= &bootloader_version,
+		.maxlen		= sizeof (int),
+		.mode		= 0444,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "io_delay_type",
+		.data		= &io_delay_type,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+#if defined(CONFIG_MMU)
+	{
+		.procname	= "randomize_va_space",
+		.data		= &randomize_va_space,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+#if defined(CONFIG_S390) && defined(CONFIG_SMP)
+	{
+		.procname	= "spin_retry",
+		.data		= &spin_retry,
+		.maxlen		= sizeof (int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+#if	defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
+	{
+		.procname	= "acpi_video_flags",
+		.data		= &acpi_realmode_flags,
+		.maxlen		= sizeof (unsigned long),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_minmax,
+	},
+#endif
+#ifdef CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN
+	{
+		.procname	= "ignore-unaligned-usertrap",
+		.data		= &no_unaligned_warning,
+		.maxlen		= sizeof (int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+#ifdef CONFIG_IA64
+	{
+		.procname	= "unaligned-dump-stack",
+		.data		= &unaligned_dump_stack,
+		.maxlen		= sizeof (int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+#ifdef CONFIG_RT_MUTEXES
+	{
+		.procname	= "max_lock_depth",
+		.data		= &max_lock_depth,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+#ifdef CONFIG_KEYS
+	{
+		.procname	= "keys",
+		.mode		= 0555,
+		.child		= key_sysctls,
+	},
+#endif
+#ifdef CONFIG_PERF_EVENTS
+	/*
+	 * User-space scripts rely on the existence of this file
+	 * as a feature check for perf_events being enabled.
+	 *
+	 * So it's an ABI, do not remove!
+	 */
+	{
+		.procname	= "perf_event_paranoid",
+		.data		= &sysctl_perf_event_paranoid,
+		.maxlen		= sizeof(sysctl_perf_event_paranoid),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "perf_event_mlock_kb",
+		.data		= &sysctl_perf_event_mlock,
+		.maxlen		= sizeof(sysctl_perf_event_mlock),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "perf_event_max_sample_rate",
+		.data		= &sysctl_perf_event_sample_rate,
+		.maxlen		= sizeof(sysctl_perf_event_sample_rate),
+		.mode		= 0644,
+		.proc_handler	= perf_proc_update_handler,
+		.extra1		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "perf_cpu_time_max_percent",
+		.data		= &sysctl_perf_cpu_time_max_percent,
+		.maxlen		= sizeof(sysctl_perf_cpu_time_max_percent),
+		.mode		= 0644,
+		.proc_handler	= perf_cpu_time_max_percent_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE_HUNDRED,
+	},
+	{
+		.procname	= "perf_event_max_stack",
+		.data		= &sysctl_perf_event_max_stack,
+		.maxlen		= sizeof(sysctl_perf_event_max_stack),
+		.mode		= 0644,
+		.proc_handler	= perf_event_max_stack_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= (void *)&six_hundred_forty_kb,
+	},
+	{
+		.procname	= "perf_event_max_contexts_per_stack",
+		.data		= &sysctl_perf_event_max_contexts_per_stack,
+		.maxlen		= sizeof(sysctl_perf_event_max_contexts_per_stack),
+		.mode		= 0644,
+		.proc_handler	= perf_event_max_stack_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE_THOUSAND,
+	},
+#endif
+	{
+		.procname	= "panic_on_warn",
+		.data		= &panic_on_warn,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#ifdef CONFIG_TREE_RCU
+	{
+		.procname	= "panic_on_rcu_stall",
+		.data		= &sysctl_panic_on_rcu_stall,
+		.maxlen		= sizeof(sysctl_panic_on_rcu_stall),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "max_rcu_stall_to_panic",
+		.data		= &sysctl_max_rcu_stall_to_panic,
+		.maxlen		= sizeof(sysctl_max_rcu_stall_to_panic),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_INT_MAX,
+	},
+#endif
+	{ }
+};
+
+static struct ctl_table vm_table[] = {
+	{
+		.procname	= "overcommit_memory",
+		.data		= &sysctl_overcommit_memory,
+		.maxlen		= sizeof(sysctl_overcommit_memory),
+		.mode		= 0644,
+		.proc_handler	= overcommit_policy_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_TWO,
+	},
+	{
+		.procname	= "overcommit_ratio",
+		.data		= &sysctl_overcommit_ratio,
+		.maxlen		= sizeof(sysctl_overcommit_ratio),
+		.mode		= 0644,
+		.proc_handler	= overcommit_ratio_handler,
+	},
+	{
+		.procname	= "overcommit_kbytes",
+		.data		= &sysctl_overcommit_kbytes,
+		.maxlen		= sizeof(sysctl_overcommit_kbytes),
+		.mode		= 0644,
+		.proc_handler	= overcommit_kbytes_handler,
+	},
+	{
+		.procname	= "page-cluster",
+		.data		= &page_cluster,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+	{
+		.procname	= "dirtytime_expire_seconds",
+		.data		= &dirtytime_expire_interval,
+		.maxlen		= sizeof(dirtytime_expire_interval),
+		.mode		= 0644,
+		.proc_handler	= dirtytime_interval_handler,
+		.extra1		= SYSCTL_ZERO,
+	},
+	{
+		.procname	= "swappiness",
+		.data		= &vm_swappiness,
+		.maxlen		= sizeof(vm_swappiness),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_TWO_HUNDRED,
+	},
+#ifdef CONFIG_NUMA
+	{
+		.procname	= "numa_stat",
+		.data		= &sysctl_vm_numa_stat,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= sysctl_vm_numa_stat_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#endif
+#ifdef CONFIG_HUGETLB_PAGE
+	{
+		.procname	= "nr_hugepages",
+		.data		= NULL,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= hugetlb_sysctl_handler,
+	},
+#ifdef CONFIG_NUMA
+	{
+		.procname       = "nr_hugepages_mempolicy",
+		.data           = NULL,
+		.maxlen         = sizeof(unsigned long),
+		.mode           = 0644,
+		.proc_handler   = &hugetlb_mempolicy_sysctl_handler,
+	},
+#endif
+	 {
+		.procname	= "hugetlb_shm_group",
+		.data		= &sysctl_hugetlb_shm_group,
+		.maxlen		= sizeof(gid_t),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	 },
+	{
+		.procname	= "nr_overcommit_hugepages",
+		.data		= NULL,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= hugetlb_overcommit_handler,
+	},
+#endif
+	{
+		.procname	= "lowmem_reserve_ratio",
+		.data		= &sysctl_lowmem_reserve_ratio,
+		.maxlen		= sizeof(sysctl_lowmem_reserve_ratio),
+		.mode		= 0644,
+		.proc_handler	= lowmem_reserve_ratio_sysctl_handler,
+	},
+	{
+		.procname	= "drop_caches",
+		.data		= &sysctl_drop_caches,
+		.maxlen		= sizeof(int),
+		.mode		= 0200,
+		.proc_handler	= drop_caches_sysctl_handler,
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_FOUR,
+	},
+#ifdef CONFIG_COMPACTION
+	{
+		.procname	= "compact_memory",
+		.data		= NULL,
+		.maxlen		= sizeof(int),
+		.mode		= 0200,
+		.proc_handler	= sysctl_compaction_handler,
+	},
+	{
+		.procname	= "compaction_proactiveness",
+		.data		= &sysctl_compaction_proactiveness,
+		.maxlen		= sizeof(sysctl_compaction_proactiveness),
+		.mode		= 0644,
+		.proc_handler	= compaction_proactiveness_sysctl_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE_HUNDRED,
+	},
+	{
+		.procname	= "extfrag_threshold",
+		.data		= &sysctl_extfrag_threshold,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE_THOUSAND,
+	},
+	{
+		.procname	= "compact_unevictable_allowed",
+		.data		= &sysctl_compact_unevictable_allowed,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax_warn_RT_change,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+
+#endif /* CONFIG_COMPACTION */
+	{
+		.procname	= "min_free_kbytes",
+		.data		= &min_free_kbytes,
+		.maxlen		= sizeof(min_free_kbytes),
+		.mode		= 0644,
+		.proc_handler	= min_free_kbytes_sysctl_handler,
+		.extra1		= SYSCTL_ZERO,
+	},
+	{
+		.procname	= "watermark_boost_factor",
+		.data		= &watermark_boost_factor,
+		.maxlen		= sizeof(watermark_boost_factor),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+	{
+		.procname	= "watermark_scale_factor",
+		.data		= &watermark_scale_factor,
+		.maxlen		= sizeof(watermark_scale_factor),
+		.mode		= 0644,
+		.proc_handler	= watermark_scale_factor_sysctl_handler,
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_THREE_THOUSAND,
+	},
+	{
+		.procname	= "percpu_pagelist_high_fraction",
+		.data		= &percpu_pagelist_high_fraction,
+		.maxlen		= sizeof(percpu_pagelist_high_fraction),
+		.mode		= 0644,
+		.proc_handler	= percpu_pagelist_high_fraction_sysctl_handler,
+		.extra1		= SYSCTL_ZERO,
+	},
+	{
+		.procname	= "page_lock_unfairness",
+		.data		= &sysctl_page_lock_unfairness,
+		.maxlen		= sizeof(sysctl_page_lock_unfairness),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+#ifdef CONFIG_MMU
+	{
+		.procname	= "max_map_count",
+		.data		= &sysctl_max_map_count,
+		.maxlen		= sizeof(sysctl_max_map_count),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+#else
+	{
+		.procname	= "nr_trim_pages",
+		.data		= &sysctl_nr_trim_pages,
+		.maxlen		= sizeof(sysctl_nr_trim_pages),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+#endif
+	{
+		.procname	= "vfs_cache_pressure",
+		.data		= &sysctl_vfs_cache_pressure,
+		.maxlen		= sizeof(sysctl_vfs_cache_pressure),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
+    defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
+	{
+		.procname	= "legacy_va_layout",
+		.data		= &sysctl_legacy_va_layout,
+		.maxlen		= sizeof(sysctl_legacy_va_layout),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+#endif
+#ifdef CONFIG_NUMA
+	{
+		.procname	= "zone_reclaim_mode",
+		.data		= &node_reclaim_mode,
+		.maxlen		= sizeof(node_reclaim_mode),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+	},
+	{
+		.procname	= "min_unmapped_ratio",
+		.data		= &sysctl_min_unmapped_ratio,
+		.maxlen		= sizeof(sysctl_min_unmapped_ratio),
+		.mode		= 0644,
+		.proc_handler	= sysctl_min_unmapped_ratio_sysctl_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE_HUNDRED,
+	},
+	{
+		.procname	= "min_slab_ratio",
+		.data		= &sysctl_min_slab_ratio,
+		.maxlen		= sizeof(sysctl_min_slab_ratio),
+		.mode		= 0644,
+		.proc_handler	= sysctl_min_slab_ratio_sysctl_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE_HUNDRED,
+	},
+#endif
+#ifdef CONFIG_SMP
+	{
+		.procname	= "stat_interval",
+		.data		= &sysctl_stat_interval,
+		.maxlen		= sizeof(sysctl_stat_interval),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_jiffies,
+	},
+	{
+		.procname	= "stat_refresh",
+		.data		= NULL,
+		.maxlen		= 0,
+		.mode		= 0600,
+		.proc_handler	= vmstat_refresh,
+	},
+#endif
+#ifdef CONFIG_MMU
+	{
+		.procname	= "mmap_min_addr",
+		.data		= &dac_mmap_min_addr,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644,
+		.proc_handler	= mmap_min_addr_handler,
+	},
+#endif
+#ifdef CONFIG_NUMA
+	{
+		.procname	= "numa_zonelist_order",
+		.data		= &numa_zonelist_order,
+		.maxlen		= NUMA_ZONELIST_ORDER_LEN,
+		.mode		= 0644,
+		.proc_handler	= numa_zonelist_order_handler,
+	},
+#endif
+#if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
+   (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
+	{
+		.procname	= "vdso_enabled",
+#ifdef CONFIG_X86_32
+		.data		= &vdso32_enabled,
+		.maxlen		= sizeof(vdso32_enabled),
+#else
+		.data		= &vdso_enabled,
+		.maxlen		= sizeof(vdso_enabled),
+#endif
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+	},
+#endif
+#ifdef CONFIG_MEMORY_FAILURE
+	{
+		.procname	= "memory_failure_early_kill",
+		.data		= &sysctl_memory_failure_early_kill,
+		.maxlen		= sizeof(sysctl_memory_failure_early_kill),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "memory_failure_recovery",
+		.data		= &sysctl_memory_failure_recovery,
+		.maxlen		= sizeof(sysctl_memory_failure_recovery),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#endif
+	{
+		.procname	= "user_reserve_kbytes",
+		.data		= &sysctl_user_reserve_kbytes,
+		.maxlen		= sizeof(sysctl_user_reserve_kbytes),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_minmax,
+	},
+	{
+		.procname	= "admin_reserve_kbytes",
+		.data		= &sysctl_admin_reserve_kbytes,
+		.maxlen		= sizeof(sysctl_admin_reserve_kbytes),
+		.mode		= 0644,
+		.proc_handler	= proc_doulongvec_minmax,
+	},
+#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
+	{
+		.procname	= "mmap_rnd_bits",
+		.data		= &mmap_rnd_bits,
+		.maxlen		= sizeof(mmap_rnd_bits),
+		.mode		= 0600,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= (void *)&mmap_rnd_bits_min,
+		.extra2		= (void *)&mmap_rnd_bits_max,
+	},
+#endif
+#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
+	{
+		.procname	= "mmap_rnd_compat_bits",
+		.data		= &mmap_rnd_compat_bits,
+		.maxlen		= sizeof(mmap_rnd_compat_bits),
+		.mode		= 0600,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= (void *)&mmap_rnd_compat_bits_min,
+		.extra2		= (void *)&mmap_rnd_compat_bits_max,
+	},
+#endif
+#ifdef CONFIG_USERFAULTFD
+	{
+		.procname	= "unprivileged_userfaultfd",
+		.data		= &sysctl_unprivileged_userfaultfd,
+		.maxlen		= sizeof(sysctl_unprivileged_userfaultfd),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#endif
+	{ }
+};
+
+static struct ctl_table debug_table[] = {
+#ifdef CONFIG_SYSCTL_EXCEPTION_TRACE
+	{
+		.procname	= "exception-trace",
+		.data		= &show_unhandled_signals,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec
+	},
+#endif
+	{ }
+};
+
+static struct ctl_table dev_table[] = {
+	{ }
+};
+
+DECLARE_SYSCTL_BASE(kernel, kern_table);
+DECLARE_SYSCTL_BASE(vm, vm_table);
+DECLARE_SYSCTL_BASE(debug, debug_table);
+DECLARE_SYSCTL_BASE(dev, dev_table);
+
+int __init sysctl_init_bases(void)
+{
+	register_sysctl_base(kernel);
+	register_sysctl_base(vm);
+	register_sysctl_base(debug);
+	register_sysctl_base(dev);
+
+	return 0;
+}
+#endif /* CONFIG_SYSCTL */
+/*
+ * No sense putting this after each symbol definition, twice,
+ * exception granted :-)
+ */
+EXPORT_SYMBOL(proc_dobool);
+EXPORT_SYMBOL(proc_dointvec);
+EXPORT_SYMBOL(proc_douintvec);
+EXPORT_SYMBOL(proc_dointvec_jiffies);
+EXPORT_SYMBOL(proc_dointvec_minmax);
+EXPORT_SYMBOL_GPL(proc_douintvec_minmax);
+EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
+EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
+EXPORT_SYMBOL(proc_dostring);
+EXPORT_SYMBOL(proc_doulongvec_minmax);
+EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
+EXPORT_SYMBOL(proc_do_large_bitmap);
diff --git a/kernel/task_work.c b/kernel/task_work.c
new file mode 100644
index 000000000..065e1ef8f
--- /dev/null
+++ b/kernel/task_work.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/spinlock.h>
+#include <linux/task_work.h>
+#include <linux/resume_user_mode.h>
+
+static struct callback_head work_exited; /* all we need is ->next == NULL */
+
+/**
+ * task_work_add - ask the @task to execute @work->func()
+ * @task: the task which should run the callback
+ * @work: the callback to run
+ * @notify: how to notify the targeted task
+ *
+ * Queue @work for task_work_run() below and notify the @task if @notify
+ * is @TWA_RESUME, @TWA_SIGNAL, or @TWA_SIGNAL_NO_IPI.
+ *
+ * @TWA_SIGNAL works like signals, in that the it will interrupt the targeted
+ * task and run the task_work, regardless of whether the task is currently
+ * running in the kernel or userspace.
+ * @TWA_SIGNAL_NO_IPI works like @TWA_SIGNAL, except it doesn't send a
+ * reschedule IPI to force the targeted task to reschedule and run task_work.
+ * This can be advantageous if there's no strict requirement that the
+ * task_work be run as soon as possible, just whenever the task enters the
+ * kernel anyway.
+ * @TWA_RESUME work is run only when the task exits the kernel and returns to
+ * user mode, or before entering guest mode.
+ *
+ * Fails if the @task is exiting/exited and thus it can't process this @work.
+ * Otherwise @work->func() will be called when the @task goes through one of
+ * the aforementioned transitions, or exits.
+ *
+ * If the targeted task is exiting, then an error is returned and the work item
+ * is not queued. It's up to the caller to arrange for an alternative mechanism
+ * in that case.
+ *
+ * Note: there is no ordering guarantee on works queued here. The task_work
+ * list is LIFO.
+ *
+ * RETURNS:
+ * 0 if succeeds or -ESRCH.
+ */
+int task_work_add(struct task_struct *task, struct callback_head *work,
+		  enum task_work_notify_mode notify)
+{
+	struct callback_head *head;
+
+	/* record the work call stack in order to print it in KASAN reports */
+	kasan_record_aux_stack(work);
+
+	head = READ_ONCE(task->task_works);
+	do {
+		if (unlikely(head == &work_exited))
+			return -ESRCH;
+		work->next = head;
+	} while (!try_cmpxchg(&task->task_works, &head, work));
+
+	switch (notify) {
+	case TWA_NONE:
+		break;
+	case TWA_RESUME:
+		set_notify_resume(task);
+		break;
+	case TWA_SIGNAL:
+		set_notify_signal(task);
+		break;
+	case TWA_SIGNAL_NO_IPI:
+		__set_notify_signal(task);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
+
+	return 0;
+}
+
+/**
+ * task_work_cancel_match - cancel a pending work added by task_work_add()
+ * @task: the task which should execute the work
+ * @match: match function to call
+ *
+ * RETURNS:
+ * The found work or NULL if not found.
+ */
+struct callback_head *
+task_work_cancel_match(struct task_struct *task,
+		       bool (*match)(struct callback_head *, void *data),
+		       void *data)
+{
+	struct callback_head **pprev = &task->task_works;
+	struct callback_head *work;
+	unsigned long flags;
+
+	if (likely(!task_work_pending(task)))
+		return NULL;
+	/*
+	 * If cmpxchg() fails we continue without updating pprev.
+	 * Either we raced with task_work_add() which added the
+	 * new entry before this work, we will find it again. Or
+	 * we raced with task_work_run(), *pprev == NULL/exited.
+	 */
+	raw_spin_lock_irqsave(&task->pi_lock, flags);
+	work = READ_ONCE(*pprev);
+	while (work) {
+		if (!match(work, data)) {
+			pprev = &work->next;
+			work = READ_ONCE(*pprev);
+		} else if (try_cmpxchg(pprev, &work, work->next))
+			break;
+	}
+	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+
+	return work;
+}
+
+static bool task_work_func_match(struct callback_head *cb, void *data)
+{
+	return cb->func == data;
+}
+
+/**
+ * task_work_cancel - cancel a pending work added by task_work_add()
+ * @task: the task which should execute the work
+ * @func: identifies the work to remove
+ *
+ * Find the last queued pending work with ->func == @func and remove
+ * it from queue.
+ *
+ * RETURNS:
+ * The found work or NULL if not found.
+ */
+struct callback_head *
+task_work_cancel(struct task_struct *task, task_work_func_t func)
+{
+	return task_work_cancel_match(task, task_work_func_match, func);
+}
+
+/**
+ * task_work_run - execute the works added by task_work_add()
+ *
+ * Flush the pending works. Should be used by the core kernel code.
+ * Called before the task returns to the user-mode or stops, or when
+ * it exits. In the latter case task_work_add() can no longer add the
+ * new work after task_work_run() returns.
+ */
+void task_work_run(void)
+{
+	struct task_struct *task = current;
+	struct callback_head *work, *head, *next;
+
+	for (;;) {
+		/*
+		 * work->func() can do task_work_add(), do not set
+		 * work_exited unless the list is empty.
+		 */
+		work = READ_ONCE(task->task_works);
+		do {
+			head = NULL;
+			if (!work) {
+				if (task->flags & PF_EXITING)
+					head = &work_exited;
+				else
+					break;
+			}
+		} while (!try_cmpxchg(&task->task_works, &work, head));
+
+		if (!work)
+			break;
+		/*
+		 * Synchronize with task_work_cancel(). It can not remove
+		 * the first entry == work, cmpxchg(task_works) must fail.
+		 * But it can remove another entry from the ->next list.
+		 */
+		raw_spin_lock_irq(&task->pi_lock);
+		raw_spin_unlock_irq(&task->pi_lock);
+
+		do {
+			next = work->next;
+			work->func(work);
+			work = next;
+			cond_resched();
+		} while (work);
+	}
+}
diff --git a/kernel/taskstats.c b/kernel/taskstats.c
new file mode 100644
index 000000000..8ce3fa0c1
--- /dev/null
+++ b/kernel/taskstats.c
@@ -0,0 +1,724 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * taskstats.c - Export per-task statistics to userland
+ *
+ * Copyright (C) Shailabh Nagar, IBM Corp. 2006
+ *           (C) Balbir Singh,   IBM Corp. 2006
+ */
+
+#include <linux/kernel.h>
+#include <linux/taskstats_kern.h>
+#include <linux/tsacct_kern.h>
+#include <linux/acct.h>
+#include <linux/delayacct.h>
+#include <linux/cpumask.h>
+#include <linux/percpu.h>
+#include <linux/slab.h>
+#include <linux/cgroupstats.h>
+#include <linux/cgroup.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/pid_namespace.h>
+#include <net/genetlink.h>
+#include <linux/atomic.h>
+#include <linux/sched/cputime.h>
+
+/*
+ * Maximum length of a cpumask that can be specified in
+ * the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute
+ */
+#define TASKSTATS_CPUMASK_MAXLEN	(100+6*NR_CPUS)
+
+static DEFINE_PER_CPU(__u32, taskstats_seqnum);
+static int family_registered;
+struct kmem_cache *taskstats_cache;
+
+static struct genl_family family;
+
+static const struct nla_policy taskstats_cmd_get_policy[] = {
+	[TASKSTATS_CMD_ATTR_PID]  = { .type = NLA_U32 },
+	[TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },
+	[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
+	[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
+
+static const struct nla_policy cgroupstats_cmd_get_policy[] = {
+	[CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
+};
+
+struct listener {
+	struct list_head list;
+	pid_t pid;
+	char valid;
+};
+
+struct listener_list {
+	struct rw_semaphore sem;
+	struct list_head list;
+};
+static DEFINE_PER_CPU(struct listener_list, listener_array);
+
+enum actions {
+	REGISTER,
+	DEREGISTER,
+	CPU_DONT_CARE
+};
+
+static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
+				size_t size)
+{
+	struct sk_buff *skb;
+	void *reply;
+
+	/*
+	 * If new attributes are added, please revisit this allocation
+	 */
+	skb = genlmsg_new(size, GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	if (!info) {
+		int seq = this_cpu_inc_return(taskstats_seqnum) - 1;
+
+		reply = genlmsg_put(skb, 0, seq, &family, 0, cmd);
+	} else
+		reply = genlmsg_put_reply(skb, info, &family, 0, cmd);
+	if (reply == NULL) {
+		nlmsg_free(skb);
+		return -EINVAL;
+	}
+
+	*skbp = skb;
+	return 0;
+}
+
+/*
+ * Send taskstats data in @skb to listener with nl_pid @pid
+ */
+static int send_reply(struct sk_buff *skb, struct genl_info *info)
+{
+	struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
+	void *reply = genlmsg_data(genlhdr);
+
+	genlmsg_end(skb, reply);
+
+	return genlmsg_reply(skb, info);
+}
+
+/*
+ * Send taskstats data in @skb to listeners registered for @cpu's exit data
+ */
+static void send_cpu_listeners(struct sk_buff *skb,
+					struct listener_list *listeners)
+{
+	struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
+	struct listener *s, *tmp;
+	struct sk_buff *skb_next, *skb_cur = skb;
+	void *reply = genlmsg_data(genlhdr);
+	int delcount = 0;
+
+	genlmsg_end(skb, reply);
+
+	down_read(&listeners->sem);
+	list_for_each_entry(s, &listeners->list, list) {
+		int rc;
+
+		skb_next = NULL;
+		if (!list_is_last(&s->list, &listeners->list)) {
+			skb_next = skb_clone(skb_cur, GFP_KERNEL);
+			if (!skb_next)
+				break;
+		}
+		rc = genlmsg_unicast(&init_net, skb_cur, s->pid);
+		if (rc == -ECONNREFUSED) {
+			s->valid = 0;
+			delcount++;
+		}
+		skb_cur = skb_next;
+	}
+	up_read(&listeners->sem);
+
+	if (skb_cur)
+		nlmsg_free(skb_cur);
+
+	if (!delcount)
+		return;
+
+	/* Delete invalidated entries */
+	down_write(&listeners->sem);
+	list_for_each_entry_safe(s, tmp, &listeners->list, list) {
+		if (!s->valid) {
+			list_del(&s->list);
+			kfree(s);
+		}
+	}
+	up_write(&listeners->sem);
+}
+
+static void exe_add_tsk(struct taskstats *stats, struct task_struct *tsk)
+{
+	/* No idea if I'm allowed to access that here, now. */
+	struct file *exe_file = get_task_exe_file(tsk);
+
+	if (exe_file) {
+		/* Following cp_new_stat64() in stat.c . */
+		stats->ac_exe_dev =
+			huge_encode_dev(exe_file->f_inode->i_sb->s_dev);
+		stats->ac_exe_inode = exe_file->f_inode->i_ino;
+		fput(exe_file);
+	} else {
+		stats->ac_exe_dev = 0;
+		stats->ac_exe_inode = 0;
+	}
+}
+
+static void fill_stats(struct user_namespace *user_ns,
+		       struct pid_namespace *pid_ns,
+		       struct task_struct *tsk, struct taskstats *stats)
+{
+	memset(stats, 0, sizeof(*stats));
+	/*
+	 * Each accounting subsystem adds calls to its functions to
+	 * fill in relevant parts of struct taskstsats as follows
+	 *
+	 *	per-task-foo(stats, tsk);
+	 */
+
+	delayacct_add_tsk(stats, tsk);
+
+	/* fill in basic acct fields */
+	stats->version = TASKSTATS_VERSION;
+	stats->nvcsw = tsk->nvcsw;
+	stats->nivcsw = tsk->nivcsw;
+	bacct_add_tsk(user_ns, pid_ns, stats, tsk);
+
+	/* fill in extended acct fields */
+	xacct_add_tsk(stats, tsk);
+
+	/* add executable info */
+	exe_add_tsk(stats, tsk);
+}
+
+static int fill_stats_for_pid(pid_t pid, struct taskstats *stats)
+{
+	struct task_struct *tsk;
+
+	tsk = find_get_task_by_vpid(pid);
+	if (!tsk)
+		return -ESRCH;
+	fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats);
+	put_task_struct(tsk);
+	return 0;
+}
+
+static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats)
+{
+	struct task_struct *tsk, *first;
+	unsigned long flags;
+	int rc = -ESRCH;
+	u64 delta, utime, stime;
+	u64 start_time;
+
+	/*
+	 * Add additional stats from live tasks except zombie thread group
+	 * leaders who are already counted with the dead tasks
+	 */
+	rcu_read_lock();
+	first = find_task_by_vpid(tgid);
+
+	if (!first || !lock_task_sighand(first, &flags))
+		goto out;
+
+	if (first->signal->stats)
+		memcpy(stats, first->signal->stats, sizeof(*stats));
+	else
+		memset(stats, 0, sizeof(*stats));
+
+	tsk = first;
+	start_time = ktime_get_ns();
+	do {
+		if (tsk->exit_state)
+			continue;
+		/*
+		 * Accounting subsystem can call its functions here to
+		 * fill in relevant parts of struct taskstsats as follows
+		 *
+		 *	per-task-foo(stats, tsk);
+		 */
+		delayacct_add_tsk(stats, tsk);
+
+		/* calculate task elapsed time in nsec */
+		delta = start_time - tsk->start_time;
+		/* Convert to micro seconds */
+		do_div(delta, NSEC_PER_USEC);
+		stats->ac_etime += delta;
+
+		task_cputime(tsk, &utime, &stime);
+		stats->ac_utime += div_u64(utime, NSEC_PER_USEC);
+		stats->ac_stime += div_u64(stime, NSEC_PER_USEC);
+
+		stats->nvcsw += tsk->nvcsw;
+		stats->nivcsw += tsk->nivcsw;
+	} while_each_thread(first, tsk);
+
+	unlock_task_sighand(first, &flags);
+	rc = 0;
+out:
+	rcu_read_unlock();
+
+	stats->version = TASKSTATS_VERSION;
+	/*
+	 * Accounting subsystems can also add calls here to modify
+	 * fields of taskstats.
+	 */
+	return rc;
+}
+
+static void fill_tgid_exit(struct task_struct *tsk)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&tsk->sighand->siglock, flags);
+	if (!tsk->signal->stats)
+		goto ret;
+
+	/*
+	 * Each accounting subsystem calls its functions here to
+	 * accumalate its per-task stats for tsk, into the per-tgid structure
+	 *
+	 *	per-task-foo(tsk->signal->stats, tsk);
+	 */
+	delayacct_add_tsk(tsk->signal->stats, tsk);
+ret:
+	spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+	return;
+}
+
+static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
+{
+	struct listener_list *listeners;
+	struct listener *s, *tmp, *s2;
+	unsigned int cpu;
+	int ret = 0;
+
+	if (!cpumask_subset(mask, cpu_possible_mask))
+		return -EINVAL;
+
+	if (current_user_ns() != &init_user_ns)
+		return -EINVAL;
+
+	if (task_active_pid_ns(current) != &init_pid_ns)
+		return -EINVAL;
+
+	if (isadd == REGISTER) {
+		for_each_cpu(cpu, mask) {
+			s = kmalloc_node(sizeof(struct listener),
+					GFP_KERNEL, cpu_to_node(cpu));
+			if (!s) {
+				ret = -ENOMEM;
+				goto cleanup;
+			}
+			s->pid = pid;
+			s->valid = 1;
+
+			listeners = &per_cpu(listener_array, cpu);
+			down_write(&listeners->sem);
+			list_for_each_entry(s2, &listeners->list, list) {
+				if (s2->pid == pid && s2->valid)
+					goto exists;
+			}
+			list_add(&s->list, &listeners->list);
+			s = NULL;
+exists:
+			up_write(&listeners->sem);
+			kfree(s); /* nop if NULL */
+		}
+		return 0;
+	}
+
+	/* Deregister or cleanup */
+cleanup:
+	for_each_cpu(cpu, mask) {
+		listeners = &per_cpu(listener_array, cpu);
+		down_write(&listeners->sem);
+		list_for_each_entry_safe(s, tmp, &listeners->list, list) {
+			if (s->pid == pid) {
+				list_del(&s->list);
+				kfree(s);
+				break;
+			}
+		}
+		up_write(&listeners->sem);
+	}
+	return ret;
+}
+
+static int parse(struct nlattr *na, struct cpumask *mask)
+{
+	char *data;
+	int len;
+	int ret;
+
+	if (na == NULL)
+		return 1;
+	len = nla_len(na);
+	if (len > TASKSTATS_CPUMASK_MAXLEN)
+		return -E2BIG;
+	if (len < 1)
+		return -EINVAL;
+	data = kmalloc(len, GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	nla_strscpy(data, na, len);
+	ret = cpulist_parse(data, mask);
+	kfree(data);
+	return ret;
+}
+
+static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
+{
+	struct nlattr *na, *ret;
+	int aggr;
+
+	aggr = (type == TASKSTATS_TYPE_PID)
+			? TASKSTATS_TYPE_AGGR_PID
+			: TASKSTATS_TYPE_AGGR_TGID;
+
+	na = nla_nest_start_noflag(skb, aggr);
+	if (!na)
+		goto err;
+
+	if (nla_put(skb, type, sizeof(pid), &pid) < 0) {
+		nla_nest_cancel(skb, na);
+		goto err;
+	}
+	ret = nla_reserve_64bit(skb, TASKSTATS_TYPE_STATS,
+				sizeof(struct taskstats), TASKSTATS_TYPE_NULL);
+	if (!ret) {
+		nla_nest_cancel(skb, na);
+		goto err;
+	}
+	nla_nest_end(skb, na);
+
+	return nla_data(ret);
+err:
+	return NULL;
+}
+
+static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
+{
+	int rc = 0;
+	struct sk_buff *rep_skb;
+	struct cgroupstats *stats;
+	struct nlattr *na;
+	size_t size;
+	u32 fd;
+	struct fd f;
+
+	na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
+	if (!na)
+		return -EINVAL;
+
+	fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
+	f = fdget(fd);
+	if (!f.file)
+		return 0;
+
+	size = nla_total_size(sizeof(struct cgroupstats));
+
+	rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,
+				size);
+	if (rc < 0)
+		goto err;
+
+	na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,
+				sizeof(struct cgroupstats));
+	if (na == NULL) {
+		nlmsg_free(rep_skb);
+		rc = -EMSGSIZE;
+		goto err;
+	}
+
+	stats = nla_data(na);
+	memset(stats, 0, sizeof(*stats));
+
+	rc = cgroupstats_build(stats, f.file->f_path.dentry);
+	if (rc < 0) {
+		nlmsg_free(rep_skb);
+		goto err;
+	}
+
+	rc = send_reply(rep_skb, info);
+
+err:
+	fdput(f);
+	return rc;
+}
+
+static int cmd_attr_register_cpumask(struct genl_info *info)
+{
+	cpumask_var_t mask;
+	int rc;
+
+	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+		return -ENOMEM;
+	rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask);
+	if (rc < 0)
+		goto out;
+	rc = add_del_listener(info->snd_portid, mask, REGISTER);
+out:
+	free_cpumask_var(mask);
+	return rc;
+}
+
+static int cmd_attr_deregister_cpumask(struct genl_info *info)
+{
+	cpumask_var_t mask;
+	int rc;
+
+	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+		return -ENOMEM;
+	rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask);
+	if (rc < 0)
+		goto out;
+	rc = add_del_listener(info->snd_portid, mask, DEREGISTER);
+out:
+	free_cpumask_var(mask);
+	return rc;
+}
+
+static size_t taskstats_packet_size(void)
+{
+	size_t size;
+
+	size = nla_total_size(sizeof(u32)) +
+		nla_total_size_64bit(sizeof(struct taskstats)) +
+		nla_total_size(0);
+
+	return size;
+}
+
+static int cmd_attr_pid(struct genl_info *info)
+{
+	struct taskstats *stats;
+	struct sk_buff *rep_skb;
+	size_t size;
+	u32 pid;
+	int rc;
+
+	size = taskstats_packet_size();
+
+	rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
+	if (rc < 0)
+		return rc;
+
+	rc = -EINVAL;
+	pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
+	stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
+	if (!stats)
+		goto err;
+
+	rc = fill_stats_for_pid(pid, stats);
+	if (rc < 0)
+		goto err;
+	return send_reply(rep_skb, info);
+err:
+	nlmsg_free(rep_skb);
+	return rc;
+}
+
+static int cmd_attr_tgid(struct genl_info *info)
+{
+	struct taskstats *stats;
+	struct sk_buff *rep_skb;
+	size_t size;
+	u32 tgid;
+	int rc;
+
+	size = taskstats_packet_size();
+
+	rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
+	if (rc < 0)
+		return rc;
+
+	rc = -EINVAL;
+	tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
+	stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
+	if (!stats)
+		goto err;
+
+	rc = fill_stats_for_tgid(tgid, stats);
+	if (rc < 0)
+		goto err;
+	return send_reply(rep_skb, info);
+err:
+	nlmsg_free(rep_skb);
+	return rc;
+}
+
+static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
+{
+	if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK])
+		return cmd_attr_register_cpumask(info);
+	else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK])
+		return cmd_attr_deregister_cpumask(info);
+	else if (info->attrs[TASKSTATS_CMD_ATTR_PID])
+		return cmd_attr_pid(info);
+	else if (info->attrs[TASKSTATS_CMD_ATTR_TGID])
+		return cmd_attr_tgid(info);
+	else
+		return -EINVAL;
+}
+
+static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
+{
+	struct signal_struct *sig = tsk->signal;
+	struct taskstats *stats_new, *stats;
+
+	/* Pairs with smp_store_release() below. */
+	stats = smp_load_acquire(&sig->stats);
+	if (stats || thread_group_empty(tsk))
+		return stats;
+
+	/* No problem if kmem_cache_zalloc() fails */
+	stats_new = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
+
+	spin_lock_irq(&tsk->sighand->siglock);
+	stats = sig->stats;
+	if (!stats) {
+		/*
+		 * Pairs with smp_store_release() above and order the
+		 * kmem_cache_zalloc().
+		 */
+		smp_store_release(&sig->stats, stats_new);
+		stats = stats_new;
+		stats_new = NULL;
+	}
+	spin_unlock_irq(&tsk->sighand->siglock);
+
+	if (stats_new)
+		kmem_cache_free(taskstats_cache, stats_new);
+
+	return stats;
+}
+
+/* Send pid data out on exit */
+void taskstats_exit(struct task_struct *tsk, int group_dead)
+{
+	int rc;
+	struct listener_list *listeners;
+	struct taskstats *stats;
+	struct sk_buff *rep_skb;
+	size_t size;
+	int is_thread_group;
+
+	if (!family_registered)
+		return;
+
+	/*
+	 * Size includes space for nested attributes
+	 */
+	size = taskstats_packet_size();
+
+	is_thread_group = !!taskstats_tgid_alloc(tsk);
+	if (is_thread_group) {
+		/* PID + STATS + TGID + STATS */
+		size = 2 * size;
+		/* fill the tsk->signal->stats structure */
+		fill_tgid_exit(tsk);
+	}
+
+	listeners = raw_cpu_ptr(&listener_array);
+	if (list_empty(&listeners->list))
+		return;
+
+	rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
+	if (rc < 0)
+		return;
+
+	stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID,
+			 task_pid_nr_ns(tsk, &init_pid_ns));
+	if (!stats)
+		goto err;
+
+	fill_stats(&init_user_ns, &init_pid_ns, tsk, stats);
+	if (group_dead)
+		stats->ac_flag |= AGROUP;
+
+	/*
+	 * Doesn't matter if tsk is the leader or the last group member leaving
+	 */
+	if (!is_thread_group || !group_dead)
+		goto send;
+
+	stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID,
+			 task_tgid_nr_ns(tsk, &init_pid_ns));
+	if (!stats)
+		goto err;
+
+	memcpy(stats, tsk->signal->stats, sizeof(*stats));
+
+send:
+	send_cpu_listeners(rep_skb, listeners);
+	return;
+err:
+	nlmsg_free(rep_skb);
+}
+
+static const struct genl_ops taskstats_ops[] = {
+	{
+		.cmd		= TASKSTATS_CMD_GET,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.doit		= taskstats_user_cmd,
+		.policy		= taskstats_cmd_get_policy,
+		.maxattr	= ARRAY_SIZE(taskstats_cmd_get_policy) - 1,
+		.flags		= GENL_ADMIN_PERM,
+	},
+	{
+		.cmd		= CGROUPSTATS_CMD_GET,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.doit		= cgroupstats_user_cmd,
+		.policy		= cgroupstats_cmd_get_policy,
+		.maxattr	= ARRAY_SIZE(cgroupstats_cmd_get_policy) - 1,
+	},
+};
+
+static struct genl_family family __ro_after_init = {
+	.name		= TASKSTATS_GENL_NAME,
+	.version	= TASKSTATS_GENL_VERSION,
+	.module		= THIS_MODULE,
+	.ops		= taskstats_ops,
+	.n_ops		= ARRAY_SIZE(taskstats_ops),
+	.resv_start_op	= CGROUPSTATS_CMD_GET + 1,
+	.netnsok	= true,
+};
+
+/* Needed early in initialization */
+void __init taskstats_init_early(void)
+{
+	unsigned int i;
+
+	taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC);
+	for_each_possible_cpu(i) {
+		INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
+		init_rwsem(&(per_cpu(listener_array, i).sem));
+	}
+}
+
+static int __init taskstats_init(void)
+{
+	int rc;
+
+	rc = genl_register_family(&family);
+	if (rc)
+		return rc;
+
+	family_registered = 1;
+	pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
+	return 0;
+}
+
+/*
+ * late initcall ensures initialization of statistics collection
+ * mechanisms precedes initialization of the taskstats interface
+ */
+late_initcall(taskstats_init);
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
new file mode 100644
index 000000000..a41753be1
--- /dev/null
+++ b/kernel/time/Kconfig
@@ -0,0 +1,209 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Timer subsystem related configuration options
+#
+
+# Options selectable by arch Kconfig
+
+# Watchdog function for clocksources to detect instabilities
+config CLOCKSOURCE_WATCHDOG
+	bool
+
+# Architecture has extra clocksource data
+config ARCH_CLOCKSOURCE_DATA
+	bool
+
+# Architecture has extra clocksource init called from registration
+config ARCH_CLOCKSOURCE_INIT
+	bool
+
+# Clocksources require validation of the clocksource against the last
+# cycle update - x86/TSC misfeature
+config CLOCKSOURCE_VALIDATE_LAST_CYCLE
+	bool
+
+# Timekeeping vsyscall support
+config GENERIC_TIME_VSYSCALL
+	bool
+
+# The generic clock events infrastructure
+config GENERIC_CLOCKEVENTS
+	def_bool !LEGACY_TIMER_TICK
+
+# Architecture can handle broadcast in a driver-agnostic way
+config ARCH_HAS_TICK_BROADCAST
+	bool
+
+# Clockevents broadcasting infrastructure
+config GENERIC_CLOCKEVENTS_BROADCAST
+	bool
+	depends on GENERIC_CLOCKEVENTS
+
+# Automatically adjust the min. reprogramming time for
+# clock event device
+config GENERIC_CLOCKEVENTS_MIN_ADJUST
+	bool
+
+# Generic update of CMOS clock
+config GENERIC_CMOS_UPDATE
+	bool
+
+# Select to handle posix CPU timers from task_work
+# and not from the timer interrupt context
+config HAVE_POSIX_CPU_TIMERS_TASK_WORK
+	bool
+
+config POSIX_CPU_TIMERS_TASK_WORK
+	bool
+	default y if POSIX_TIMERS && HAVE_POSIX_CPU_TIMERS_TASK_WORK
+
+config LEGACY_TIMER_TICK
+	bool
+	help
+	  The legacy timer tick helper is used by platforms that
+	  lack support for the generic clockevent framework.
+	  New platforms should use generic clockevents instead.
+
+config TIME_KUNIT_TEST
+	tristate "KUnit test for kernel/time functions" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  Enable this option to test RTC library functions.
+
+	  If unsure, say N.
+
+config CONTEXT_TRACKING
+	bool
+
+config CONTEXT_TRACKING_IDLE
+	bool
+	select CONTEXT_TRACKING
+	help
+	  Tracks idle state on behalf of RCU.
+
+if GENERIC_CLOCKEVENTS
+menu "Timers subsystem"
+
+# Core internal switch. Selected by NO_HZ_COMMON / HIGH_RES_TIMERS. This is
+# only related to the tick functionality. Oneshot clockevent devices
+# are supported independent of this.
+config TICK_ONESHOT
+	bool
+
+config NO_HZ_COMMON
+	bool
+	select TICK_ONESHOT
+
+choice
+	prompt "Timer tick handling"
+	default NO_HZ_IDLE if NO_HZ
+
+config HZ_PERIODIC
+	bool "Periodic timer ticks (constant rate, no dynticks)"
+	help
+	  This option keeps the tick running periodically at a constant
+	  rate, even when the CPU doesn't need it.
+
+config NO_HZ_IDLE
+	bool "Idle dynticks system (tickless idle)"
+	select NO_HZ_COMMON
+	help
+	  This option enables a tickless idle system: timer interrupts
+	  will only trigger on an as-needed basis when the system is idle.
+	  This is usually interesting for energy saving.
+
+	  Most of the time you want to say Y here.
+
+config NO_HZ_FULL
+	bool "Full dynticks system (tickless)"
+	# NO_HZ_COMMON dependency
+	# We need at least one periodic CPU for timekeeping
+	depends on SMP
+	depends on HAVE_CONTEXT_TRACKING_USER
+	# VIRT_CPU_ACCOUNTING_GEN dependency
+	depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
+	select NO_HZ_COMMON
+	select RCU_NOCB_CPU
+	select VIRT_CPU_ACCOUNTING_GEN
+	select IRQ_WORK
+	select CPU_ISOLATION
+	help
+	 Adaptively try to shutdown the tick whenever possible, even when
+	 the CPU is running tasks. Typically this requires running a single
+	 task on the CPU. Chances for running tickless are maximized when
+	 the task mostly runs in userspace and has few kernel activity.
+
+	 You need to fill up the nohz_full boot parameter with the
+	 desired range of dynticks CPUs to use it. This is implemented at
+	 the expense of some overhead in user <-> kernel transitions:
+	 syscalls, exceptions and interrupts.
+
+	 By default, without passing the nohz_full parameter, this behaves just
+	 like NO_HZ_IDLE.
+
+	 If you're a distro say Y.
+
+endchoice
+
+config CONTEXT_TRACKING_USER
+	bool
+	depends on HAVE_CONTEXT_TRACKING_USER
+	select CONTEXT_TRACKING
+	help
+	  Track transitions between kernel and user on behalf of RCU and
+	  tickless cputime accounting. The former case relies on context
+	  tracking to enter/exit RCU extended quiescent states.
+
+config CONTEXT_TRACKING_USER_FORCE
+	bool "Force user context tracking"
+	depends on CONTEXT_TRACKING_USER
+	default y if !NO_HZ_FULL
+	help
+	  The major pre-requirement for full dynticks to work is to
+	  support the user context tracking subsystem. But there are also
+	  other dependencies to provide in order to make the full
+	  dynticks working.
+
+	  This option stands for testing when an arch implements the
+	  user context tracking backend but doesn't yet fulfill all the
+	  requirements to make the full dynticks feature working.
+	  Without the full dynticks, there is no way to test the support
+	  for user context tracking and the subsystems that rely on it: RCU
+	  userspace extended quiescent state and tickless cputime
+	  accounting. This option copes with the absence of the full
+	  dynticks subsystem by forcing the user context tracking on all
+	  CPUs in the system.
+
+	  Say Y only if you're working on the development of an
+	  architecture backend for the user context tracking.
+
+	  Say N otherwise, this option brings an overhead that you
+	  don't want in production.
+
+config NO_HZ
+	bool "Old Idle dynticks config"
+	help
+	  This is the old config entry that enables dynticks idle.
+	  We keep it around for a little while to enforce backward
+	  compatibility with older config files.
+
+config HIGH_RES_TIMERS
+	bool "High Resolution Timer Support"
+	select TICK_ONESHOT
+	help
+	  This option enables high resolution timer support. If your
+	  hardware is not capable then this option only increases
+	  the size of the kernel image.
+
+config CLOCKSOURCE_WATCHDOG_MAX_SKEW_US
+	int "Clocksource watchdog maximum allowable skew (in μs)"
+	depends on CLOCKSOURCE_WATCHDOG
+	range 50 1000
+	default 100
+	help
+	  Specify the maximum amount of allowable watchdog skew in
+	  microseconds before reporting the clocksource to be unstable.
+
+endmenu
+endif
diff --git a/kernel/time/Makefile b/kernel/time/Makefile
new file mode 100644
index 000000000..7e875e63f
--- /dev/null
+++ b/kernel/time/Makefile
@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y += time.o timer.o hrtimer.o
+obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o
+obj-y += timeconv.o timecounter.o alarmtimer.o
+
+ifeq ($(CONFIG_POSIX_TIMERS),y)
+ obj-y += posix-timers.o posix-cpu-timers.o posix-clock.o itimer.o
+else
+ obj-y += posix-stubs.o
+endif
+
+obj-$(CONFIG_GENERIC_CLOCKEVENTS)		+= clockevents.o tick-common.o
+ifeq ($(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST),y)
+ obj-y						+= tick-broadcast.o
+ obj-$(CONFIG_TICK_ONESHOT)			+= tick-broadcast-hrtimer.o
+endif
+obj-$(CONFIG_GENERIC_SCHED_CLOCK)		+= sched_clock.o
+obj-$(CONFIG_TICK_ONESHOT)			+= tick-oneshot.o tick-sched.o
+obj-$(CONFIG_LEGACY_TIMER_TICK)			+= tick-legacy.o
+obj-$(CONFIG_HAVE_GENERIC_VDSO)			+= vsyscall.o
+obj-$(CONFIG_DEBUG_FS)				+= timekeeping_debug.o
+obj-$(CONFIG_TEST_UDELAY)			+= test_udelay.o
+obj-$(CONFIG_TIME_NS)				+= namespace.o
+obj-$(CONFIG_TEST_CLOCKSOURCE_WATCHDOG)		+= clocksource-wdtest.o
+obj-$(CONFIG_TIME_KUNIT_TEST)			+= time_test.o
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
new file mode 100644
index 000000000..7e5dff602
--- /dev/null
+++ b/kernel/time/alarmtimer.c
@@ -0,0 +1,964 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Alarmtimer interface
+ *
+ * This interface provides a timer which is similar to hrtimers,
+ * but triggers a RTC alarm if the box is suspend.
+ *
+ * This interface is influenced by the Android RTC Alarm timer
+ * interface.
+ *
+ * Copyright (C) 2010 IBM Corporation
+ *
+ * Author: John Stultz <john.stultz@linaro.org>
+ */
+#include <linux/time.h>
+#include <linux/hrtimer.h>
+#include <linux/timerqueue.h>
+#include <linux/rtc.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/debug.h>
+#include <linux/alarmtimer.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/posix-timers.h>
+#include <linux/workqueue.h>
+#include <linux/freezer.h>
+#include <linux/compat.h>
+#include <linux/module.h>
+#include <linux/time_namespace.h>
+
+#include "posix-timers.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/alarmtimer.h>
+
+/**
+ * struct alarm_base - Alarm timer bases
+ * @lock:		Lock for syncrhonized access to the base
+ * @timerqueue:		Timerqueue head managing the list of events
+ * @get_ktime:		Function to read the time correlating to the base
+ * @get_timespec:	Function to read the namespace time correlating to the base
+ * @base_clockid:	clockid for the base
+ */
+static struct alarm_base {
+	spinlock_t		lock;
+	struct timerqueue_head	timerqueue;
+	ktime_t			(*get_ktime)(void);
+	void			(*get_timespec)(struct timespec64 *tp);
+	clockid_t		base_clockid;
+} alarm_bases[ALARM_NUMTYPE];
+
+#if defined(CONFIG_POSIX_TIMERS) || defined(CONFIG_RTC_CLASS)
+/* freezer information to handle clock_nanosleep triggered wakeups */
+static enum alarmtimer_type freezer_alarmtype;
+static ktime_t freezer_expires;
+static ktime_t freezer_delta;
+static DEFINE_SPINLOCK(freezer_delta_lock);
+#endif
+
+#ifdef CONFIG_RTC_CLASS
+/* rtc timer and device for setting alarm wakeups at suspend */
+static struct rtc_timer		rtctimer;
+static struct rtc_device	*rtcdev;
+static DEFINE_SPINLOCK(rtcdev_lock);
+
+/**
+ * alarmtimer_get_rtcdev - Return selected rtcdevice
+ *
+ * This function returns the rtc device to use for wakealarms.
+ */
+struct rtc_device *alarmtimer_get_rtcdev(void)
+{
+	unsigned long flags;
+	struct rtc_device *ret;
+
+	spin_lock_irqsave(&rtcdev_lock, flags);
+	ret = rtcdev;
+	spin_unlock_irqrestore(&rtcdev_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
+
+static int alarmtimer_rtc_add_device(struct device *dev,
+				struct class_interface *class_intf)
+{
+	unsigned long flags;
+	struct rtc_device *rtc = to_rtc_device(dev);
+	struct platform_device *pdev;
+	int ret = 0;
+
+	if (rtcdev)
+		return -EBUSY;
+
+	if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
+		return -1;
+	if (!device_may_wakeup(rtc->dev.parent))
+		return -1;
+
+	pdev = platform_device_register_data(dev, "alarmtimer",
+					     PLATFORM_DEVID_AUTO, NULL, 0);
+	if (!IS_ERR(pdev))
+		device_init_wakeup(&pdev->dev, true);
+
+	spin_lock_irqsave(&rtcdev_lock, flags);
+	if (!IS_ERR(pdev) && !rtcdev) {
+		if (!try_module_get(rtc->owner)) {
+			ret = -1;
+			goto unlock;
+		}
+
+		rtcdev = rtc;
+		/* hold a reference so it doesn't go away */
+		get_device(dev);
+		pdev = NULL;
+	} else {
+		ret = -1;
+	}
+unlock:
+	spin_unlock_irqrestore(&rtcdev_lock, flags);
+
+	platform_device_unregister(pdev);
+
+	return ret;
+}
+
+static inline void alarmtimer_rtc_timer_init(void)
+{
+	rtc_timer_init(&rtctimer, NULL, NULL);
+}
+
+static struct class_interface alarmtimer_rtc_interface = {
+	.add_dev = &alarmtimer_rtc_add_device,
+};
+
+static int alarmtimer_rtc_interface_setup(void)
+{
+	alarmtimer_rtc_interface.class = rtc_class;
+	return class_interface_register(&alarmtimer_rtc_interface);
+}
+static void alarmtimer_rtc_interface_remove(void)
+{
+	class_interface_unregister(&alarmtimer_rtc_interface);
+}
+#else
+static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
+static inline void alarmtimer_rtc_interface_remove(void) { }
+static inline void alarmtimer_rtc_timer_init(void) { }
+#endif
+
+/**
+ * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
+ * @base: pointer to the base where the timer is being run
+ * @alarm: pointer to alarm being enqueued.
+ *
+ * Adds alarm to a alarm_base timerqueue
+ *
+ * Must hold base->lock when calling.
+ */
+static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
+{
+	if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
+		timerqueue_del(&base->timerqueue, &alarm->node);
+
+	timerqueue_add(&base->timerqueue, &alarm->node);
+	alarm->state |= ALARMTIMER_STATE_ENQUEUED;
+}
+
+/**
+ * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
+ * @base: pointer to the base where the timer is running
+ * @alarm: pointer to alarm being removed
+ *
+ * Removes alarm to a alarm_base timerqueue
+ *
+ * Must hold base->lock when calling.
+ */
+static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
+{
+	if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
+		return;
+
+	timerqueue_del(&base->timerqueue, &alarm->node);
+	alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
+}
+
+
+/**
+ * alarmtimer_fired - Handles alarm hrtimer being fired.
+ * @timer: pointer to hrtimer being run
+ *
+ * When a alarm timer fires, this runs through the timerqueue to
+ * see which alarms expired, and runs those. If there are more alarm
+ * timers queued for the future, we set the hrtimer to fire when
+ * the next future alarm timer expires.
+ */
+static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
+{
+	struct alarm *alarm = container_of(timer, struct alarm, timer);
+	struct alarm_base *base = &alarm_bases[alarm->type];
+	unsigned long flags;
+	int ret = HRTIMER_NORESTART;
+	int restart = ALARMTIMER_NORESTART;
+
+	spin_lock_irqsave(&base->lock, flags);
+	alarmtimer_dequeue(base, alarm);
+	spin_unlock_irqrestore(&base->lock, flags);
+
+	if (alarm->function)
+		restart = alarm->function(alarm, base->get_ktime());
+
+	spin_lock_irqsave(&base->lock, flags);
+	if (restart != ALARMTIMER_NORESTART) {
+		hrtimer_set_expires(&alarm->timer, alarm->node.expires);
+		alarmtimer_enqueue(base, alarm);
+		ret = HRTIMER_RESTART;
+	}
+	spin_unlock_irqrestore(&base->lock, flags);
+
+	trace_alarmtimer_fired(alarm, base->get_ktime());
+	return ret;
+
+}
+
+ktime_t alarm_expires_remaining(const struct alarm *alarm)
+{
+	struct alarm_base *base = &alarm_bases[alarm->type];
+	return ktime_sub(alarm->node.expires, base->get_ktime());
+}
+EXPORT_SYMBOL_GPL(alarm_expires_remaining);
+
+#ifdef CONFIG_RTC_CLASS
+/**
+ * alarmtimer_suspend - Suspend time callback
+ * @dev: unused
+ *
+ * When we are going into suspend, we look through the bases
+ * to see which is the soonest timer to expire. We then
+ * set an rtc timer to fire that far into the future, which
+ * will wake us from suspend.
+ */
+static int alarmtimer_suspend(struct device *dev)
+{
+	ktime_t min, now, expires;
+	int i, ret, type;
+	struct rtc_device *rtc;
+	unsigned long flags;
+	struct rtc_time tm;
+
+	spin_lock_irqsave(&freezer_delta_lock, flags);
+	min = freezer_delta;
+	expires = freezer_expires;
+	type = freezer_alarmtype;
+	freezer_delta = 0;
+	spin_unlock_irqrestore(&freezer_delta_lock, flags);
+
+	rtc = alarmtimer_get_rtcdev();
+	/* If we have no rtcdev, just return */
+	if (!rtc)
+		return 0;
+
+	/* Find the soonest timer to expire*/
+	for (i = 0; i < ALARM_NUMTYPE; i++) {
+		struct alarm_base *base = &alarm_bases[i];
+		struct timerqueue_node *next;
+		ktime_t delta;
+
+		spin_lock_irqsave(&base->lock, flags);
+		next = timerqueue_getnext(&base->timerqueue);
+		spin_unlock_irqrestore(&base->lock, flags);
+		if (!next)
+			continue;
+		delta = ktime_sub(next->expires, base->get_ktime());
+		if (!min || (delta < min)) {
+			expires = next->expires;
+			min = delta;
+			type = i;
+		}
+	}
+	if (min == 0)
+		return 0;
+
+	if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
+		pm_wakeup_event(dev, 2 * MSEC_PER_SEC);
+		return -EBUSY;
+	}
+
+	trace_alarmtimer_suspend(expires, type);
+
+	/* Setup an rtc timer to fire that far in the future */
+	rtc_timer_cancel(rtc, &rtctimer);
+	rtc_read_time(rtc, &tm);
+	now = rtc_tm_to_ktime(tm);
+	now = ktime_add(now, min);
+
+	/* Set alarm, if in the past reject suspend briefly to handle */
+	ret = rtc_timer_start(rtc, &rtctimer, now, 0);
+	if (ret < 0)
+		pm_wakeup_event(dev, MSEC_PER_SEC);
+	return ret;
+}
+
+static int alarmtimer_resume(struct device *dev)
+{
+	struct rtc_device *rtc;
+
+	rtc = alarmtimer_get_rtcdev();
+	if (rtc)
+		rtc_timer_cancel(rtc, &rtctimer);
+	return 0;
+}
+
+#else
+static int alarmtimer_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int alarmtimer_resume(struct device *dev)
+{
+	return 0;
+}
+#endif
+
+static void
+__alarm_init(struct alarm *alarm, enum alarmtimer_type type,
+	     enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
+{
+	timerqueue_init(&alarm->node);
+	alarm->timer.function = alarmtimer_fired;
+	alarm->function = function;
+	alarm->type = type;
+	alarm->state = ALARMTIMER_STATE_INACTIVE;
+}
+
+/**
+ * alarm_init - Initialize an alarm structure
+ * @alarm: ptr to alarm to be initialized
+ * @type: the type of the alarm
+ * @function: callback that is run when the alarm fires
+ */
+void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
+		enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
+{
+	hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
+		     HRTIMER_MODE_ABS);
+	__alarm_init(alarm, type, function);
+}
+EXPORT_SYMBOL_GPL(alarm_init);
+
+/**
+ * alarm_start - Sets an absolute alarm to fire
+ * @alarm: ptr to alarm to set
+ * @start: time to run the alarm
+ */
+void alarm_start(struct alarm *alarm, ktime_t start)
+{
+	struct alarm_base *base = &alarm_bases[alarm->type];
+	unsigned long flags;
+
+	spin_lock_irqsave(&base->lock, flags);
+	alarm->node.expires = start;
+	alarmtimer_enqueue(base, alarm);
+	hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
+	spin_unlock_irqrestore(&base->lock, flags);
+
+	trace_alarmtimer_start(alarm, base->get_ktime());
+}
+EXPORT_SYMBOL_GPL(alarm_start);
+
+/**
+ * alarm_start_relative - Sets a relative alarm to fire
+ * @alarm: ptr to alarm to set
+ * @start: time relative to now to run the alarm
+ */
+void alarm_start_relative(struct alarm *alarm, ktime_t start)
+{
+	struct alarm_base *base = &alarm_bases[alarm->type];
+
+	start = ktime_add_safe(start, base->get_ktime());
+	alarm_start(alarm, start);
+}
+EXPORT_SYMBOL_GPL(alarm_start_relative);
+
+void alarm_restart(struct alarm *alarm)
+{
+	struct alarm_base *base = &alarm_bases[alarm->type];
+	unsigned long flags;
+
+	spin_lock_irqsave(&base->lock, flags);
+	hrtimer_set_expires(&alarm->timer, alarm->node.expires);
+	hrtimer_restart(&alarm->timer);
+	alarmtimer_enqueue(base, alarm);
+	spin_unlock_irqrestore(&base->lock, flags);
+}
+EXPORT_SYMBOL_GPL(alarm_restart);
+
+/**
+ * alarm_try_to_cancel - Tries to cancel an alarm timer
+ * @alarm: ptr to alarm to be canceled
+ *
+ * Returns 1 if the timer was canceled, 0 if it was not running,
+ * and -1 if the callback was running
+ */
+int alarm_try_to_cancel(struct alarm *alarm)
+{
+	struct alarm_base *base = &alarm_bases[alarm->type];
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&base->lock, flags);
+	ret = hrtimer_try_to_cancel(&alarm->timer);
+	if (ret >= 0)
+		alarmtimer_dequeue(base, alarm);
+	spin_unlock_irqrestore(&base->lock, flags);
+
+	trace_alarmtimer_cancel(alarm, base->get_ktime());
+	return ret;
+}
+EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
+
+
+/**
+ * alarm_cancel - Spins trying to cancel an alarm timer until it is done
+ * @alarm: ptr to alarm to be canceled
+ *
+ * Returns 1 if the timer was canceled, 0 if it was not active.
+ */
+int alarm_cancel(struct alarm *alarm)
+{
+	for (;;) {
+		int ret = alarm_try_to_cancel(alarm);
+		if (ret >= 0)
+			return ret;
+		hrtimer_cancel_wait_running(&alarm->timer);
+	}
+}
+EXPORT_SYMBOL_GPL(alarm_cancel);
+
+
+u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
+{
+	u64 overrun = 1;
+	ktime_t delta;
+
+	delta = ktime_sub(now, alarm->node.expires);
+
+	if (delta < 0)
+		return 0;
+
+	if (unlikely(delta >= interval)) {
+		s64 incr = ktime_to_ns(interval);
+
+		overrun = ktime_divns(delta, incr);
+
+		alarm->node.expires = ktime_add_ns(alarm->node.expires,
+							incr*overrun);
+
+		if (alarm->node.expires > now)
+			return overrun;
+		/*
+		 * This (and the ktime_add() below) is the
+		 * correction for exact:
+		 */
+		overrun++;
+	}
+
+	alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
+	return overrun;
+}
+EXPORT_SYMBOL_GPL(alarm_forward);
+
+static u64 __alarm_forward_now(struct alarm *alarm, ktime_t interval, bool throttle)
+{
+	struct alarm_base *base = &alarm_bases[alarm->type];
+	ktime_t now = base->get_ktime();
+
+	if (IS_ENABLED(CONFIG_HIGH_RES_TIMERS) && throttle) {
+		/*
+		 * Same issue as with posix_timer_fn(). Timers which are
+		 * periodic but the signal is ignored can starve the system
+		 * with a very small interval. The real fix which was
+		 * promised in the context of posix_timer_fn() never
+		 * materialized, but someone should really work on it.
+		 *
+		 * To prevent DOS fake @now to be 1 jiffie out which keeps
+		 * the overrun accounting correct but creates an
+		 * inconsistency vs. timer_gettime(2).
+		 */
+		ktime_t kj = NSEC_PER_SEC / HZ;
+
+		if (interval < kj)
+			now = ktime_add(now, kj);
+	}
+
+	return alarm_forward(alarm, now, interval);
+}
+
+u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
+{
+	return __alarm_forward_now(alarm, interval, false);
+}
+EXPORT_SYMBOL_GPL(alarm_forward_now);
+
+#ifdef CONFIG_POSIX_TIMERS
+
+static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
+{
+	struct alarm_base *base;
+	unsigned long flags;
+	ktime_t delta;
+
+	switch(type) {
+	case ALARM_REALTIME:
+		base = &alarm_bases[ALARM_REALTIME];
+		type = ALARM_REALTIME_FREEZER;
+		break;
+	case ALARM_BOOTTIME:
+		base = &alarm_bases[ALARM_BOOTTIME];
+		type = ALARM_BOOTTIME_FREEZER;
+		break;
+	default:
+		WARN_ONCE(1, "Invalid alarm type: %d\n", type);
+		return;
+	}
+
+	delta = ktime_sub(absexp, base->get_ktime());
+
+	spin_lock_irqsave(&freezer_delta_lock, flags);
+	if (!freezer_delta || (delta < freezer_delta)) {
+		freezer_delta = delta;
+		freezer_expires = absexp;
+		freezer_alarmtype = type;
+	}
+	spin_unlock_irqrestore(&freezer_delta_lock, flags);
+}
+
+/**
+ * clock2alarm - helper that converts from clockid to alarmtypes
+ * @clockid: clockid.
+ */
+static enum alarmtimer_type clock2alarm(clockid_t clockid)
+{
+	if (clockid == CLOCK_REALTIME_ALARM)
+		return ALARM_REALTIME;
+	if (clockid == CLOCK_BOOTTIME_ALARM)
+		return ALARM_BOOTTIME;
+	return -1;
+}
+
+/**
+ * alarm_handle_timer - Callback for posix timers
+ * @alarm: alarm that fired
+ * @now: time at the timer expiration
+ *
+ * Posix timer callback for expired alarm timers.
+ *
+ * Return: whether the timer is to be restarted
+ */
+static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
+							ktime_t now)
+{
+	struct k_itimer *ptr = container_of(alarm, struct k_itimer,
+					    it.alarm.alarmtimer);
+	enum alarmtimer_restart result = ALARMTIMER_NORESTART;
+	unsigned long flags;
+	int si_private = 0;
+
+	spin_lock_irqsave(&ptr->it_lock, flags);
+
+	ptr->it_active = 0;
+	if (ptr->it_interval)
+		si_private = ++ptr->it_requeue_pending;
+
+	if (posix_timer_event(ptr, si_private) && ptr->it_interval) {
+		/*
+		 * Handle ignored signals and rearm the timer. This will go
+		 * away once we handle ignored signals proper. Ensure that
+		 * small intervals cannot starve the system.
+		 */
+		ptr->it_overrun += __alarm_forward_now(alarm, ptr->it_interval, true);
+		++ptr->it_requeue_pending;
+		ptr->it_active = 1;
+		result = ALARMTIMER_RESTART;
+	}
+	spin_unlock_irqrestore(&ptr->it_lock, flags);
+
+	return result;
+}
+
+/**
+ * alarm_timer_rearm - Posix timer callback for rearming timer
+ * @timr:	Pointer to the posixtimer data struct
+ */
+static void alarm_timer_rearm(struct k_itimer *timr)
+{
+	struct alarm *alarm = &timr->it.alarm.alarmtimer;
+
+	timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
+	alarm_start(alarm, alarm->node.expires);
+}
+
+/**
+ * alarm_timer_forward - Posix timer callback for forwarding timer
+ * @timr:	Pointer to the posixtimer data struct
+ * @now:	Current time to forward the timer against
+ */
+static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now)
+{
+	struct alarm *alarm = &timr->it.alarm.alarmtimer;
+
+	return alarm_forward(alarm, timr->it_interval, now);
+}
+
+/**
+ * alarm_timer_remaining - Posix timer callback to retrieve remaining time
+ * @timr:	Pointer to the posixtimer data struct
+ * @now:	Current time to calculate against
+ */
+static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
+{
+	struct alarm *alarm = &timr->it.alarm.alarmtimer;
+
+	return ktime_sub(alarm->node.expires, now);
+}
+
+/**
+ * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer
+ * @timr:	Pointer to the posixtimer data struct
+ */
+static int alarm_timer_try_to_cancel(struct k_itimer *timr)
+{
+	return alarm_try_to_cancel(&timr->it.alarm.alarmtimer);
+}
+
+/**
+ * alarm_timer_wait_running - Posix timer callback to wait for a timer
+ * @timr:	Pointer to the posixtimer data struct
+ *
+ * Called from the core code when timer cancel detected that the callback
+ * is running. @timr is unlocked and rcu read lock is held to prevent it
+ * from being freed.
+ */
+static void alarm_timer_wait_running(struct k_itimer *timr)
+{
+	hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer);
+}
+
+/**
+ * alarm_timer_arm - Posix timer callback to arm a timer
+ * @timr:	Pointer to the posixtimer data struct
+ * @expires:	The new expiry time
+ * @absolute:	Expiry value is absolute time
+ * @sigev_none:	Posix timer does not deliver signals
+ */
+static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
+			    bool absolute, bool sigev_none)
+{
+	struct alarm *alarm = &timr->it.alarm.alarmtimer;
+	struct alarm_base *base = &alarm_bases[alarm->type];
+
+	if (!absolute)
+		expires = ktime_add_safe(expires, base->get_ktime());
+	if (sigev_none)
+		alarm->node.expires = expires;
+	else
+		alarm_start(&timr->it.alarm.alarmtimer, expires);
+}
+
+/**
+ * alarm_clock_getres - posix getres interface
+ * @which_clock: clockid
+ * @tp: timespec to fill
+ *
+ * Returns the granularity of underlying alarm base clock
+ */
+static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
+{
+	if (!alarmtimer_get_rtcdev())
+		return -EINVAL;
+
+	tp->tv_sec = 0;
+	tp->tv_nsec = hrtimer_resolution;
+	return 0;
+}
+
+/**
+ * alarm_clock_get_timespec - posix clock_get_timespec interface
+ * @which_clock: clockid
+ * @tp: timespec to fill.
+ *
+ * Provides the underlying alarm base time in a tasks time namespace.
+ */
+static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp)
+{
+	struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
+
+	if (!alarmtimer_get_rtcdev())
+		return -EINVAL;
+
+	base->get_timespec(tp);
+
+	return 0;
+}
+
+/**
+ * alarm_clock_get_ktime - posix clock_get_ktime interface
+ * @which_clock: clockid
+ *
+ * Provides the underlying alarm base time in the root namespace.
+ */
+static ktime_t alarm_clock_get_ktime(clockid_t which_clock)
+{
+	struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
+
+	if (!alarmtimer_get_rtcdev())
+		return -EINVAL;
+
+	return base->get_ktime();
+}
+
+/**
+ * alarm_timer_create - posix timer_create interface
+ * @new_timer: k_itimer pointer to manage
+ *
+ * Initializes the k_itimer structure.
+ */
+static int alarm_timer_create(struct k_itimer *new_timer)
+{
+	enum  alarmtimer_type type;
+
+	if (!alarmtimer_get_rtcdev())
+		return -EOPNOTSUPP;
+
+	if (!capable(CAP_WAKE_ALARM))
+		return -EPERM;
+
+	type = clock2alarm(new_timer->it_clock);
+	alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
+	return 0;
+}
+
+/**
+ * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
+ * @alarm: ptr to alarm that fired
+ * @now: time at the timer expiration
+ *
+ * Wakes up the task that set the alarmtimer
+ *
+ * Return: ALARMTIMER_NORESTART
+ */
+static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
+								ktime_t now)
+{
+	struct task_struct *task = (struct task_struct *)alarm->data;
+
+	alarm->data = NULL;
+	if (task)
+		wake_up_process(task);
+	return ALARMTIMER_NORESTART;
+}
+
+/**
+ * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
+ * @alarm: ptr to alarmtimer
+ * @absexp: absolute expiration time
+ * @type: alarm type (BOOTTIME/REALTIME).
+ *
+ * Sets the alarm timer and sleeps until it is fired or interrupted.
+ */
+static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
+				enum alarmtimer_type type)
+{
+	struct restart_block *restart;
+	alarm->data = (void *)current;
+	do {
+		set_current_state(TASK_INTERRUPTIBLE);
+		alarm_start(alarm, absexp);
+		if (likely(alarm->data))
+			schedule();
+
+		alarm_cancel(alarm);
+	} while (alarm->data && !signal_pending(current));
+
+	__set_current_state(TASK_RUNNING);
+
+	destroy_hrtimer_on_stack(&alarm->timer);
+
+	if (!alarm->data)
+		return 0;
+
+	if (freezing(current))
+		alarmtimer_freezerset(absexp, type);
+	restart = &current->restart_block;
+	if (restart->nanosleep.type != TT_NONE) {
+		struct timespec64 rmt;
+		ktime_t rem;
+
+		rem = ktime_sub(absexp, alarm_bases[type].get_ktime());
+
+		if (rem <= 0)
+			return 0;
+		rmt = ktime_to_timespec64(rem);
+
+		return nanosleep_copyout(restart, &rmt);
+	}
+	return -ERESTART_RESTARTBLOCK;
+}
+
+static void
+alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type,
+		    enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
+{
+	hrtimer_init_on_stack(&alarm->timer, alarm_bases[type].base_clockid,
+			      HRTIMER_MODE_ABS);
+	__alarm_init(alarm, type, function);
+}
+
+/**
+ * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
+ * @restart: ptr to restart block
+ *
+ * Handles restarted clock_nanosleep calls
+ */
+static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
+{
+	enum  alarmtimer_type type = restart->nanosleep.clockid;
+	ktime_t exp = restart->nanosleep.expires;
+	struct alarm alarm;
+
+	alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
+
+	return alarmtimer_do_nsleep(&alarm, exp, type);
+}
+
+/**
+ * alarm_timer_nsleep - alarmtimer nanosleep
+ * @which_clock: clockid
+ * @flags: determines abstime or relative
+ * @tsreq: requested sleep time (abs or rel)
+ *
+ * Handles clock_nanosleep calls against _ALARM clockids
+ */
+static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
+			      const struct timespec64 *tsreq)
+{
+	enum  alarmtimer_type type = clock2alarm(which_clock);
+	struct restart_block *restart = &current->restart_block;
+	struct alarm alarm;
+	ktime_t exp;
+	int ret = 0;
+
+	if (!alarmtimer_get_rtcdev())
+		return -EOPNOTSUPP;
+
+	if (flags & ~TIMER_ABSTIME)
+		return -EINVAL;
+
+	if (!capable(CAP_WAKE_ALARM))
+		return -EPERM;
+
+	alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup);
+
+	exp = timespec64_to_ktime(*tsreq);
+	/* Convert (if necessary) to absolute time */
+	if (flags != TIMER_ABSTIME) {
+		ktime_t now = alarm_bases[type].get_ktime();
+
+		exp = ktime_add_safe(now, exp);
+	} else {
+		exp = timens_ktime_to_host(which_clock, exp);
+	}
+
+	ret = alarmtimer_do_nsleep(&alarm, exp, type);
+	if (ret != -ERESTART_RESTARTBLOCK)
+		return ret;
+
+	/* abs timers don't set remaining time or restart */
+	if (flags == TIMER_ABSTIME)
+		return -ERESTARTNOHAND;
+
+	restart->nanosleep.clockid = type;
+	restart->nanosleep.expires = exp;
+	set_restart_fn(restart, alarm_timer_nsleep_restart);
+	return ret;
+}
+
+const struct k_clock alarm_clock = {
+	.clock_getres		= alarm_clock_getres,
+	.clock_get_ktime	= alarm_clock_get_ktime,
+	.clock_get_timespec	= alarm_clock_get_timespec,
+	.timer_create		= alarm_timer_create,
+	.timer_set		= common_timer_set,
+	.timer_del		= common_timer_del,
+	.timer_get		= common_timer_get,
+	.timer_arm		= alarm_timer_arm,
+	.timer_rearm		= alarm_timer_rearm,
+	.timer_forward		= alarm_timer_forward,
+	.timer_remaining	= alarm_timer_remaining,
+	.timer_try_to_cancel	= alarm_timer_try_to_cancel,
+	.timer_wait_running	= alarm_timer_wait_running,
+	.nsleep			= alarm_timer_nsleep,
+};
+#endif /* CONFIG_POSIX_TIMERS */
+
+
+/* Suspend hook structures */
+static const struct dev_pm_ops alarmtimer_pm_ops = {
+	.suspend = alarmtimer_suspend,
+	.resume = alarmtimer_resume,
+};
+
+static struct platform_driver alarmtimer_driver = {
+	.driver = {
+		.name = "alarmtimer",
+		.pm = &alarmtimer_pm_ops,
+	}
+};
+
+static void get_boottime_timespec(struct timespec64 *tp)
+{
+	ktime_get_boottime_ts64(tp);
+	timens_add_boottime(tp);
+}
+
+/**
+ * alarmtimer_init - Initialize alarm timer code
+ *
+ * This function initializes the alarm bases and registers
+ * the posix clock ids.
+ */
+static int __init alarmtimer_init(void)
+{
+	int error;
+	int i;
+
+	alarmtimer_rtc_timer_init();
+
+	/* Initialize alarm bases */
+	alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
+	alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real;
+	alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64;
+	alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
+	alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime;
+	alarm_bases[ALARM_BOOTTIME].get_timespec = get_boottime_timespec;
+	for (i = 0; i < ALARM_NUMTYPE; i++) {
+		timerqueue_init_head(&alarm_bases[i].timerqueue);
+		spin_lock_init(&alarm_bases[i].lock);
+	}
+
+	error = alarmtimer_rtc_interface_setup();
+	if (error)
+		return error;
+
+	error = platform_driver_register(&alarmtimer_driver);
+	if (error)
+		goto out_if;
+
+	return 0;
+out_if:
+	alarmtimer_rtc_interface_remove();
+	return error;
+}
+device_initcall(alarmtimer_init);
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
new file mode 100644
index 000000000..5d85014d5
--- /dev/null
+++ b/kernel/time/clockevents.c
@@ -0,0 +1,778 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file contains functions which manage clock event devices.
+ *
+ * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
+ * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
+ * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
+ */
+
+#include <linux/clockchips.h>
+#include <linux/hrtimer.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/smp.h>
+#include <linux/device.h>
+
+#include "tick-internal.h"
+
+/* The registered clock event devices */
+static LIST_HEAD(clockevent_devices);
+static LIST_HEAD(clockevents_released);
+/* Protection for the above */
+static DEFINE_RAW_SPINLOCK(clockevents_lock);
+/* Protection for unbind operations */
+static DEFINE_MUTEX(clockevents_mutex);
+
+struct ce_unbind {
+	struct clock_event_device *ce;
+	int res;
+};
+
+static u64 cev_delta2ns(unsigned long latch, struct clock_event_device *evt,
+			bool ismax)
+{
+	u64 clc = (u64) latch << evt->shift;
+	u64 rnd;
+
+	if (WARN_ON(!evt->mult))
+		evt->mult = 1;
+	rnd = (u64) evt->mult - 1;
+
+	/*
+	 * Upper bound sanity check. If the backwards conversion is
+	 * not equal latch, we know that the above shift overflowed.
+	 */
+	if ((clc >> evt->shift) != (u64)latch)
+		clc = ~0ULL;
+
+	/*
+	 * Scaled math oddities:
+	 *
+	 * For mult <= (1 << shift) we can safely add mult - 1 to
+	 * prevent integer rounding loss. So the backwards conversion
+	 * from nsec to device ticks will be correct.
+	 *
+	 * For mult > (1 << shift), i.e. device frequency is > 1GHz we
+	 * need to be careful. Adding mult - 1 will result in a value
+	 * which when converted back to device ticks can be larger
+	 * than latch by up to (mult - 1) >> shift. For the min_delta
+	 * calculation we still want to apply this in order to stay
+	 * above the minimum device ticks limit. For the upper limit
+	 * we would end up with a latch value larger than the upper
+	 * limit of the device, so we omit the add to stay below the
+	 * device upper boundary.
+	 *
+	 * Also omit the add if it would overflow the u64 boundary.
+	 */
+	if ((~0ULL - clc > rnd) &&
+	    (!ismax || evt->mult <= (1ULL << evt->shift)))
+		clc += rnd;
+
+	do_div(clc, evt->mult);
+
+	/* Deltas less than 1usec are pointless noise */
+	return clc > 1000 ? clc : 1000;
+}
+
+/**
+ * clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds
+ * @latch:	value to convert
+ * @evt:	pointer to clock event device descriptor
+ *
+ * Math helper, returns latch value converted to nanoseconds (bound checked)
+ */
+u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
+{
+	return cev_delta2ns(latch, evt, false);
+}
+EXPORT_SYMBOL_GPL(clockevent_delta2ns);
+
+static int __clockevents_switch_state(struct clock_event_device *dev,
+				      enum clock_event_state state)
+{
+	if (dev->features & CLOCK_EVT_FEAT_DUMMY)
+		return 0;
+
+	/* Transition with new state-specific callbacks */
+	switch (state) {
+	case CLOCK_EVT_STATE_DETACHED:
+		/* The clockevent device is getting replaced. Shut it down. */
+
+	case CLOCK_EVT_STATE_SHUTDOWN:
+		if (dev->set_state_shutdown)
+			return dev->set_state_shutdown(dev);
+		return 0;
+
+	case CLOCK_EVT_STATE_PERIODIC:
+		/* Core internal bug */
+		if (!(dev->features & CLOCK_EVT_FEAT_PERIODIC))
+			return -ENOSYS;
+		if (dev->set_state_periodic)
+			return dev->set_state_periodic(dev);
+		return 0;
+
+	case CLOCK_EVT_STATE_ONESHOT:
+		/* Core internal bug */
+		if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
+			return -ENOSYS;
+		if (dev->set_state_oneshot)
+			return dev->set_state_oneshot(dev);
+		return 0;
+
+	case CLOCK_EVT_STATE_ONESHOT_STOPPED:
+		/* Core internal bug */
+		if (WARN_ONCE(!clockevent_state_oneshot(dev),
+			      "Current state: %d\n",
+			      clockevent_get_state(dev)))
+			return -EINVAL;
+
+		if (dev->set_state_oneshot_stopped)
+			return dev->set_state_oneshot_stopped(dev);
+		else
+			return -ENOSYS;
+
+	default:
+		return -ENOSYS;
+	}
+}
+
+/**
+ * clockevents_switch_state - set the operating state of a clock event device
+ * @dev:	device to modify
+ * @state:	new state
+ *
+ * Must be called with interrupts disabled !
+ */
+void clockevents_switch_state(struct clock_event_device *dev,
+			      enum clock_event_state state)
+{
+	if (clockevent_get_state(dev) != state) {
+		if (__clockevents_switch_state(dev, state))
+			return;
+
+		clockevent_set_state(dev, state);
+
+		/*
+		 * A nsec2cyc multiplicator of 0 is invalid and we'd crash
+		 * on it, so fix it up and emit a warning:
+		 */
+		if (clockevent_state_oneshot(dev)) {
+			if (WARN_ON(!dev->mult))
+				dev->mult = 1;
+		}
+	}
+}
+
+/**
+ * clockevents_shutdown - shutdown the device and clear next_event
+ * @dev:	device to shutdown
+ */
+void clockevents_shutdown(struct clock_event_device *dev)
+{
+	clockevents_switch_state(dev, CLOCK_EVT_STATE_SHUTDOWN);
+	dev->next_event = KTIME_MAX;
+}
+
+/**
+ * clockevents_tick_resume -	Resume the tick device before using it again
+ * @dev:			device to resume
+ */
+int clockevents_tick_resume(struct clock_event_device *dev)
+{
+	int ret = 0;
+
+	if (dev->tick_resume)
+		ret = dev->tick_resume(dev);
+
+	return ret;
+}
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST
+
+/* Limit min_delta to a jiffie */
+#define MIN_DELTA_LIMIT		(NSEC_PER_SEC / HZ)
+
+/**
+ * clockevents_increase_min_delta - raise minimum delta of a clock event device
+ * @dev:       device to increase the minimum delta
+ *
+ * Returns 0 on success, -ETIME when the minimum delta reached the limit.
+ */
+static int clockevents_increase_min_delta(struct clock_event_device *dev)
+{
+	/* Nothing to do if we already reached the limit */
+	if (dev->min_delta_ns >= MIN_DELTA_LIMIT) {
+		printk_deferred(KERN_WARNING
+				"CE: Reprogramming failure. Giving up\n");
+		dev->next_event = KTIME_MAX;
+		return -ETIME;
+	}
+
+	if (dev->min_delta_ns < 5000)
+		dev->min_delta_ns = 5000;
+	else
+		dev->min_delta_ns += dev->min_delta_ns >> 1;
+
+	if (dev->min_delta_ns > MIN_DELTA_LIMIT)
+		dev->min_delta_ns = MIN_DELTA_LIMIT;
+
+	printk_deferred(KERN_WARNING
+			"CE: %s increased min_delta_ns to %llu nsec\n",
+			dev->name ? dev->name : "?",
+			(unsigned long long) dev->min_delta_ns);
+	return 0;
+}
+
+/**
+ * clockevents_program_min_delta - Set clock event device to the minimum delay.
+ * @dev:	device to program
+ *
+ * Returns 0 on success, -ETIME when the retry loop failed.
+ */
+static int clockevents_program_min_delta(struct clock_event_device *dev)
+{
+	unsigned long long clc;
+	int64_t delta;
+	int i;
+
+	for (i = 0;;) {
+		delta = dev->min_delta_ns;
+		dev->next_event = ktime_add_ns(ktime_get(), delta);
+
+		if (clockevent_state_shutdown(dev))
+			return 0;
+
+		dev->retries++;
+		clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
+		if (dev->set_next_event((unsigned long) clc, dev) == 0)
+			return 0;
+
+		if (++i > 2) {
+			/*
+			 * We tried 3 times to program the device with the
+			 * given min_delta_ns. Try to increase the minimum
+			 * delta, if that fails as well get out of here.
+			 */
+			if (clockevents_increase_min_delta(dev))
+				return -ETIME;
+			i = 0;
+		}
+	}
+}
+
+#else  /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
+
+/**
+ * clockevents_program_min_delta - Set clock event device to the minimum delay.
+ * @dev:	device to program
+ *
+ * Returns 0 on success, -ETIME when the retry loop failed.
+ */
+static int clockevents_program_min_delta(struct clock_event_device *dev)
+{
+	unsigned long long clc;
+	int64_t delta = 0;
+	int i;
+
+	for (i = 0; i < 10; i++) {
+		delta += dev->min_delta_ns;
+		dev->next_event = ktime_add_ns(ktime_get(), delta);
+
+		if (clockevent_state_shutdown(dev))
+			return 0;
+
+		dev->retries++;
+		clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
+		if (dev->set_next_event((unsigned long) clc, dev) == 0)
+			return 0;
+	}
+	return -ETIME;
+}
+
+#endif /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
+
+/**
+ * clockevents_program_event - Reprogram the clock event device.
+ * @dev:	device to program
+ * @expires:	absolute expiry time (monotonic clock)
+ * @force:	program minimum delay if expires can not be set
+ *
+ * Returns 0 on success, -ETIME when the event is in the past.
+ */
+int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
+			      bool force)
+{
+	unsigned long long clc;
+	int64_t delta;
+	int rc;
+
+	if (WARN_ON_ONCE(expires < 0))
+		return -ETIME;
+
+	dev->next_event = expires;
+
+	if (clockevent_state_shutdown(dev))
+		return 0;
+
+	/* We must be in ONESHOT state here */
+	WARN_ONCE(!clockevent_state_oneshot(dev), "Current state: %d\n",
+		  clockevent_get_state(dev));
+
+	/* Shortcut for clockevent devices that can deal with ktime. */
+	if (dev->features & CLOCK_EVT_FEAT_KTIME)
+		return dev->set_next_ktime(expires, dev);
+
+	delta = ktime_to_ns(ktime_sub(expires, ktime_get()));
+	if (delta <= 0)
+		return force ? clockevents_program_min_delta(dev) : -ETIME;
+
+	delta = min(delta, (int64_t) dev->max_delta_ns);
+	delta = max(delta, (int64_t) dev->min_delta_ns);
+
+	clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
+	rc = dev->set_next_event((unsigned long) clc, dev);
+
+	return (rc && force) ? clockevents_program_min_delta(dev) : rc;
+}
+
+/*
+ * Called after a notify add to make devices available which were
+ * released from the notifier call.
+ */
+static void clockevents_notify_released(void)
+{
+	struct clock_event_device *dev;
+
+	while (!list_empty(&clockevents_released)) {
+		dev = list_entry(clockevents_released.next,
+				 struct clock_event_device, list);
+		list_move(&dev->list, &clockevent_devices);
+		tick_check_new_device(dev);
+	}
+}
+
+/*
+ * Try to install a replacement clock event device
+ */
+static int clockevents_replace(struct clock_event_device *ced)
+{
+	struct clock_event_device *dev, *newdev = NULL;
+
+	list_for_each_entry(dev, &clockevent_devices, list) {
+		if (dev == ced || !clockevent_state_detached(dev))
+			continue;
+
+		if (!tick_check_replacement(newdev, dev))
+			continue;
+
+		if (!try_module_get(dev->owner))
+			continue;
+
+		if (newdev)
+			module_put(newdev->owner);
+		newdev = dev;
+	}
+	if (newdev) {
+		tick_install_replacement(newdev);
+		list_del_init(&ced->list);
+	}
+	return newdev ? 0 : -EBUSY;
+}
+
+/*
+ * Called with clockevents_mutex and clockevents_lock held
+ */
+static int __clockevents_try_unbind(struct clock_event_device *ced, int cpu)
+{
+	/* Fast track. Device is unused */
+	if (clockevent_state_detached(ced)) {
+		list_del_init(&ced->list);
+		return 0;
+	}
+
+	return ced == per_cpu(tick_cpu_device, cpu).evtdev ? -EAGAIN : -EBUSY;
+}
+
+/*
+ * SMP function call to unbind a device
+ */
+static void __clockevents_unbind(void *arg)
+{
+	struct ce_unbind *cu = arg;
+	int res;
+
+	raw_spin_lock(&clockevents_lock);
+	res = __clockevents_try_unbind(cu->ce, smp_processor_id());
+	if (res == -EAGAIN)
+		res = clockevents_replace(cu->ce);
+	cu->res = res;
+	raw_spin_unlock(&clockevents_lock);
+}
+
+/*
+ * Issues smp function call to unbind a per cpu device. Called with
+ * clockevents_mutex held.
+ */
+static int clockevents_unbind(struct clock_event_device *ced, int cpu)
+{
+	struct ce_unbind cu = { .ce = ced, .res = -ENODEV };
+
+	smp_call_function_single(cpu, __clockevents_unbind, &cu, 1);
+	return cu.res;
+}
+
+/*
+ * Unbind a clockevents device.
+ */
+int clockevents_unbind_device(struct clock_event_device *ced, int cpu)
+{
+	int ret;
+
+	mutex_lock(&clockevents_mutex);
+	ret = clockevents_unbind(ced, cpu);
+	mutex_unlock(&clockevents_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(clockevents_unbind_device);
+
+/**
+ * clockevents_register_device - register a clock event device
+ * @dev:	device to register
+ */
+void clockevents_register_device(struct clock_event_device *dev)
+{
+	unsigned long flags;
+
+	/* Initialize state to DETACHED */
+	clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED);
+
+	if (!dev->cpumask) {
+		WARN_ON(num_possible_cpus() > 1);
+		dev->cpumask = cpumask_of(smp_processor_id());
+	}
+
+	if (dev->cpumask == cpu_all_mask) {
+		WARN(1, "%s cpumask == cpu_all_mask, using cpu_possible_mask instead\n",
+		     dev->name);
+		dev->cpumask = cpu_possible_mask;
+	}
+
+	raw_spin_lock_irqsave(&clockevents_lock, flags);
+
+	list_add(&dev->list, &clockevent_devices);
+	tick_check_new_device(dev);
+	clockevents_notify_released();
+
+	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
+}
+EXPORT_SYMBOL_GPL(clockevents_register_device);
+
+static void clockevents_config(struct clock_event_device *dev, u32 freq)
+{
+	u64 sec;
+
+	if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
+		return;
+
+	/*
+	 * Calculate the maximum number of seconds we can sleep. Limit
+	 * to 10 minutes for hardware which can program more than
+	 * 32bit ticks so we still get reasonable conversion values.
+	 */
+	sec = dev->max_delta_ticks;
+	do_div(sec, freq);
+	if (!sec)
+		sec = 1;
+	else if (sec > 600 && dev->max_delta_ticks > UINT_MAX)
+		sec = 600;
+
+	clockevents_calc_mult_shift(dev, freq, sec);
+	dev->min_delta_ns = cev_delta2ns(dev->min_delta_ticks, dev, false);
+	dev->max_delta_ns = cev_delta2ns(dev->max_delta_ticks, dev, true);
+}
+
+/**
+ * clockevents_config_and_register - Configure and register a clock event device
+ * @dev:	device to register
+ * @freq:	The clock frequency
+ * @min_delta:	The minimum clock ticks to program in oneshot mode
+ * @max_delta:	The maximum clock ticks to program in oneshot mode
+ *
+ * min/max_delta can be 0 for devices which do not support oneshot mode.
+ */
+void clockevents_config_and_register(struct clock_event_device *dev,
+				     u32 freq, unsigned long min_delta,
+				     unsigned long max_delta)
+{
+	dev->min_delta_ticks = min_delta;
+	dev->max_delta_ticks = max_delta;
+	clockevents_config(dev, freq);
+	clockevents_register_device(dev);
+}
+EXPORT_SYMBOL_GPL(clockevents_config_and_register);
+
+int __clockevents_update_freq(struct clock_event_device *dev, u32 freq)
+{
+	clockevents_config(dev, freq);
+
+	if (clockevent_state_oneshot(dev))
+		return clockevents_program_event(dev, dev->next_event, false);
+
+	if (clockevent_state_periodic(dev))
+		return __clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC);
+
+	return 0;
+}
+
+/**
+ * clockevents_update_freq - Update frequency and reprogram a clock event device.
+ * @dev:	device to modify
+ * @freq:	new device frequency
+ *
+ * Reconfigure and reprogram a clock event device in oneshot
+ * mode. Must be called on the cpu for which the device delivers per
+ * cpu timer events. If called for the broadcast device the core takes
+ * care of serialization.
+ *
+ * Returns 0 on success, -ETIME when the event is in the past.
+ */
+int clockevents_update_freq(struct clock_event_device *dev, u32 freq)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+	ret = tick_broadcast_update_freq(dev, freq);
+	if (ret == -ENODEV)
+		ret = __clockevents_update_freq(dev, freq);
+	local_irq_restore(flags);
+	return ret;
+}
+
+/*
+ * Noop handler when we shut down an event device
+ */
+void clockevents_handle_noop(struct clock_event_device *dev)
+{
+}
+
+/**
+ * clockevents_exchange_device - release and request clock devices
+ * @old:	device to release (can be NULL)
+ * @new:	device to request (can be NULL)
+ *
+ * Called from various tick functions with clockevents_lock held and
+ * interrupts disabled.
+ */
+void clockevents_exchange_device(struct clock_event_device *old,
+				 struct clock_event_device *new)
+{
+	/*
+	 * Caller releases a clock event device. We queue it into the
+	 * released list and do a notify add later.
+	 */
+	if (old) {
+		module_put(old->owner);
+		clockevents_switch_state(old, CLOCK_EVT_STATE_DETACHED);
+		list_move(&old->list, &clockevents_released);
+	}
+
+	if (new) {
+		BUG_ON(!clockevent_state_detached(new));
+		clockevents_shutdown(new);
+	}
+}
+
+/**
+ * clockevents_suspend - suspend clock devices
+ */
+void clockevents_suspend(void)
+{
+	struct clock_event_device *dev;
+
+	list_for_each_entry_reverse(dev, &clockevent_devices, list)
+		if (dev->suspend && !clockevent_state_detached(dev))
+			dev->suspend(dev);
+}
+
+/**
+ * clockevents_resume - resume clock devices
+ */
+void clockevents_resume(void)
+{
+	struct clock_event_device *dev;
+
+	list_for_each_entry(dev, &clockevent_devices, list)
+		if (dev->resume && !clockevent_state_detached(dev))
+			dev->resume(dev);
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+/**
+ * tick_offline_cpu - Take CPU out of the broadcast mechanism
+ * @cpu:	The outgoing CPU
+ *
+ * Called on the outgoing CPU after it took itself offline.
+ */
+void tick_offline_cpu(unsigned int cpu)
+{
+	raw_spin_lock(&clockevents_lock);
+	tick_broadcast_offline(cpu);
+	raw_spin_unlock(&clockevents_lock);
+}
+# endif
+
+/**
+ * tick_cleanup_dead_cpu - Cleanup the tick and clockevents of a dead cpu
+ * @cpu:	The dead CPU
+ */
+void tick_cleanup_dead_cpu(int cpu)
+{
+	struct clock_event_device *dev, *tmp;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&clockevents_lock, flags);
+
+	tick_shutdown(cpu);
+	/*
+	 * Unregister the clock event devices which were
+	 * released from the users in the notify chain.
+	 */
+	list_for_each_entry_safe(dev, tmp, &clockevents_released, list)
+		list_del(&dev->list);
+	/*
+	 * Now check whether the CPU has left unused per cpu devices
+	 */
+	list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) {
+		if (cpumask_test_cpu(cpu, dev->cpumask) &&
+		    cpumask_weight(dev->cpumask) == 1 &&
+		    !tick_is_broadcast_device(dev)) {
+			BUG_ON(!clockevent_state_detached(dev));
+			list_del(&dev->list);
+		}
+	}
+	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
+}
+#endif
+
+#ifdef CONFIG_SYSFS
+static struct bus_type clockevents_subsys = {
+	.name		= "clockevents",
+	.dev_name       = "clockevent",
+};
+
+static DEFINE_PER_CPU(struct device, tick_percpu_dev);
+static struct tick_device *tick_get_tick_dev(struct device *dev);
+
+static ssize_t current_device_show(struct device *dev,
+				   struct device_attribute *attr,
+				   char *buf)
+{
+	struct tick_device *td;
+	ssize_t count = 0;
+
+	raw_spin_lock_irq(&clockevents_lock);
+	td = tick_get_tick_dev(dev);
+	if (td && td->evtdev)
+		count = snprintf(buf, PAGE_SIZE, "%s\n", td->evtdev->name);
+	raw_spin_unlock_irq(&clockevents_lock);
+	return count;
+}
+static DEVICE_ATTR_RO(current_device);
+
+/* We don't support the abomination of removable broadcast devices */
+static ssize_t unbind_device_store(struct device *dev,
+				   struct device_attribute *attr,
+				   const char *buf, size_t count)
+{
+	char name[CS_NAME_LEN];
+	ssize_t ret = sysfs_get_uname(buf, name, count);
+	struct clock_event_device *ce = NULL, *iter;
+
+	if (ret < 0)
+		return ret;
+
+	ret = -ENODEV;
+	mutex_lock(&clockevents_mutex);
+	raw_spin_lock_irq(&clockevents_lock);
+	list_for_each_entry(iter, &clockevent_devices, list) {
+		if (!strcmp(iter->name, name)) {
+			ret = __clockevents_try_unbind(iter, dev->id);
+			ce = iter;
+			break;
+		}
+	}
+	raw_spin_unlock_irq(&clockevents_lock);
+	/*
+	 * We hold clockevents_mutex, so ce can't go away
+	 */
+	if (ret == -EAGAIN)
+		ret = clockevents_unbind(ce, dev->id);
+	mutex_unlock(&clockevents_mutex);
+	return ret ? ret : count;
+}
+static DEVICE_ATTR_WO(unbind_device);
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+static struct device tick_bc_dev = {
+	.init_name	= "broadcast",
+	.id		= 0,
+	.bus		= &clockevents_subsys,
+};
+
+static struct tick_device *tick_get_tick_dev(struct device *dev)
+{
+	return dev == &tick_bc_dev ? tick_get_broadcast_device() :
+		&per_cpu(tick_cpu_device, dev->id);
+}
+
+static __init int tick_broadcast_init_sysfs(void)
+{
+	int err = device_register(&tick_bc_dev);
+
+	if (!err)
+		err = device_create_file(&tick_bc_dev, &dev_attr_current_device);
+	return err;
+}
+#else
+static struct tick_device *tick_get_tick_dev(struct device *dev)
+{
+	return &per_cpu(tick_cpu_device, dev->id);
+}
+static inline int tick_broadcast_init_sysfs(void) { return 0; }
+#endif
+
+static int __init tick_init_sysfs(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		struct device *dev = &per_cpu(tick_percpu_dev, cpu);
+		int err;
+
+		dev->id = cpu;
+		dev->bus = &clockevents_subsys;
+		err = device_register(dev);
+		if (!err)
+			err = device_create_file(dev, &dev_attr_current_device);
+		if (!err)
+			err = device_create_file(dev, &dev_attr_unbind_device);
+		if (err)
+			return err;
+	}
+	return tick_broadcast_init_sysfs();
+}
+
+static int __init clockevents_init_sysfs(void)
+{
+	int err = subsys_system_register(&clockevents_subsys, NULL);
+
+	if (!err)
+		err = tick_init_sysfs();
+	return err;
+}
+device_initcall(clockevents_init_sysfs);
+#endif /* SYSFS */
diff --git a/kernel/time/clocksource-wdtest.c b/kernel/time/clocksource-wdtest.c
new file mode 100644
index 000000000..df922f49d
--- /dev/null
+++ b/kernel/time/clocksource-wdtest.c
@@ -0,0 +1,201 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Unit test for the clocksource watchdog.
+ *
+ * Copyright (C) 2021 Facebook, Inc.
+ *
+ * Author: Paul E. McKenney <paulmck@kernel.org>
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/device.h>
+#include <linux/clocksource.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/sched.h> /* for spin_unlock_irq() using preempt_count() m68k */
+#include <linux/tick.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#include <linux/prandom.h>
+#include <linux/cpu.h>
+
+#include "tick-internal.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@kernel.org>");
+
+static int holdoff = IS_BUILTIN(CONFIG_TEST_CLOCKSOURCE_WATCHDOG) ? 10 : 0;
+module_param(holdoff, int, 0444);
+MODULE_PARM_DESC(holdoff, "Time to wait to start test (s).");
+
+/* Watchdog kthread's task_struct pointer for debug purposes. */
+static struct task_struct *wdtest_task;
+
+static u64 wdtest_jiffies_read(struct clocksource *cs)
+{
+	return (u64)jiffies;
+}
+
+static struct clocksource clocksource_wdtest_jiffies = {
+	.name			= "wdtest-jiffies",
+	.rating			= 1, /* lowest valid rating*/
+	.uncertainty_margin	= TICK_NSEC,
+	.read			= wdtest_jiffies_read,
+	.mask			= CLOCKSOURCE_MASK(32),
+	.flags			= CLOCK_SOURCE_MUST_VERIFY,
+	.mult			= TICK_NSEC << JIFFIES_SHIFT, /* details above */
+	.shift			= JIFFIES_SHIFT,
+	.max_cycles		= 10,
+};
+
+static int wdtest_ktime_read_ndelays;
+static bool wdtest_ktime_read_fuzz;
+
+static u64 wdtest_ktime_read(struct clocksource *cs)
+{
+	int wkrn = READ_ONCE(wdtest_ktime_read_ndelays);
+	static int sign = 1;
+	u64 ret;
+
+	if (wkrn) {
+		udelay(cs->uncertainty_margin / 250);
+		WRITE_ONCE(wdtest_ktime_read_ndelays, wkrn - 1);
+	}
+	ret = ktime_get_real_fast_ns();
+	if (READ_ONCE(wdtest_ktime_read_fuzz)) {
+		sign = -sign;
+		ret = ret + sign * 100 * NSEC_PER_MSEC;
+	}
+	return ret;
+}
+
+static void wdtest_ktime_cs_mark_unstable(struct clocksource *cs)
+{
+	pr_info("--- Marking %s unstable due to clocksource watchdog.\n", cs->name);
+}
+
+#define KTIME_FLAGS (CLOCK_SOURCE_IS_CONTINUOUS | \
+		     CLOCK_SOURCE_VALID_FOR_HRES | \
+		     CLOCK_SOURCE_MUST_VERIFY | \
+		     CLOCK_SOURCE_VERIFY_PERCPU)
+
+static struct clocksource clocksource_wdtest_ktime = {
+	.name			= "wdtest-ktime",
+	.rating			= 300,
+	.read			= wdtest_ktime_read,
+	.mask			= CLOCKSOURCE_MASK(64),
+	.flags			= KTIME_FLAGS,
+	.mark_unstable		= wdtest_ktime_cs_mark_unstable,
+	.list			= LIST_HEAD_INIT(clocksource_wdtest_ktime.list),
+};
+
+/* Reset the clocksource if needed. */
+static void wdtest_ktime_clocksource_reset(void)
+{
+	if (clocksource_wdtest_ktime.flags & CLOCK_SOURCE_UNSTABLE) {
+		clocksource_unregister(&clocksource_wdtest_ktime);
+		clocksource_wdtest_ktime.flags = KTIME_FLAGS;
+		schedule_timeout_uninterruptible(HZ / 10);
+		clocksource_register_khz(&clocksource_wdtest_ktime, 1000 * 1000);
+	}
+}
+
+/* Run the specified series of watchdog tests. */
+static int wdtest_func(void *arg)
+{
+	unsigned long j1, j2;
+	char *s;
+	int i;
+
+	schedule_timeout_uninterruptible(holdoff * HZ);
+
+	/*
+	 * Verify that jiffies-like clocksources get the manually
+	 * specified uncertainty margin.
+	 */
+	pr_info("--- Verify jiffies-like uncertainty margin.\n");
+	__clocksource_register(&clocksource_wdtest_jiffies);
+	WARN_ON_ONCE(clocksource_wdtest_jiffies.uncertainty_margin != TICK_NSEC);
+
+	j1 = clocksource_wdtest_jiffies.read(&clocksource_wdtest_jiffies);
+	schedule_timeout_uninterruptible(HZ);
+	j2 = clocksource_wdtest_jiffies.read(&clocksource_wdtest_jiffies);
+	WARN_ON_ONCE(j1 == j2);
+
+	clocksource_unregister(&clocksource_wdtest_jiffies);
+
+	/*
+	 * Verify that tsc-like clocksources are assigned a reasonable
+	 * uncertainty margin.
+	 */
+	pr_info("--- Verify tsc-like uncertainty margin.\n");
+	clocksource_register_khz(&clocksource_wdtest_ktime, 1000 * 1000);
+	WARN_ON_ONCE(clocksource_wdtest_ktime.uncertainty_margin < NSEC_PER_USEC);
+
+	j1 = clocksource_wdtest_ktime.read(&clocksource_wdtest_ktime);
+	udelay(1);
+	j2 = clocksource_wdtest_ktime.read(&clocksource_wdtest_ktime);
+	pr_info("--- tsc-like times: %lu - %lu = %lu.\n", j2, j1, j2 - j1);
+	WARN_ON_ONCE(time_before(j2, j1 + NSEC_PER_USEC));
+
+	/* Verify tsc-like stability with various numbers of errors injected. */
+	for (i = 0; i <= max_cswd_read_retries + 1; i++) {
+		if (i <= 1 && i < max_cswd_read_retries)
+			s = "";
+		else if (i <= max_cswd_read_retries)
+			s = ", expect message";
+		else
+			s = ", expect clock skew";
+		pr_info("--- Watchdog with %dx error injection, %lu retries%s.\n", i, max_cswd_read_retries, s);
+		WRITE_ONCE(wdtest_ktime_read_ndelays, i);
+		schedule_timeout_uninterruptible(2 * HZ);
+		WARN_ON_ONCE(READ_ONCE(wdtest_ktime_read_ndelays));
+		WARN_ON_ONCE((i <= max_cswd_read_retries) !=
+			     !(clocksource_wdtest_ktime.flags & CLOCK_SOURCE_UNSTABLE));
+		wdtest_ktime_clocksource_reset();
+	}
+
+	/* Verify tsc-like stability with clock-value-fuzz error injection. */
+	pr_info("--- Watchdog clock-value-fuzz error injection, expect clock skew and per-CPU mismatches.\n");
+	WRITE_ONCE(wdtest_ktime_read_fuzz, true);
+	schedule_timeout_uninterruptible(2 * HZ);
+	WARN_ON_ONCE(!(clocksource_wdtest_ktime.flags & CLOCK_SOURCE_UNSTABLE));
+	clocksource_verify_percpu(&clocksource_wdtest_ktime);
+	WRITE_ONCE(wdtest_ktime_read_fuzz, false);
+
+	clocksource_unregister(&clocksource_wdtest_ktime);
+
+	pr_info("--- Done with test.\n");
+	return 0;
+}
+
+static void wdtest_print_module_parms(void)
+{
+	pr_alert("--- holdoff=%d\n", holdoff);
+}
+
+/* Cleanup function. */
+static void clocksource_wdtest_cleanup(void)
+{
+}
+
+static int __init clocksource_wdtest_init(void)
+{
+	int ret = 0;
+
+	wdtest_print_module_parms();
+
+	/* Create watchdog-test task. */
+	wdtest_task = kthread_run(wdtest_func, NULL, "wdtest");
+	if (IS_ERR(wdtest_task)) {
+		ret = PTR_ERR(wdtest_task);
+		pr_warn("%s: Failed to create wdtest kthread.\n", __func__);
+		wdtest_task = NULL;
+		return ret;
+	}
+
+	return 0;
+}
+
+module_init(clocksource_wdtest_init);
+module_exit(clocksource_wdtest_cleanup);
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
new file mode 100644
index 000000000..1c90e710d
--- /dev/null
+++ b/kernel/time/clocksource.c
@@ -0,0 +1,1496 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * This file contains the functions which manage clocksource drivers.
+ *
+ * Copyright (C) 2004, 2005 IBM, John Stultz (johnstul@us.ibm.com)
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/device.h>
+#include <linux/clocksource.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/sched.h> /* for spin_unlock_irq() using preempt_count() m68k */
+#include <linux/tick.h>
+#include <linux/kthread.h>
+#include <linux/prandom.h>
+#include <linux/cpu.h>
+
+#include "tick-internal.h"
+#include "timekeeping_internal.h"
+
+/**
+ * clocks_calc_mult_shift - calculate mult/shift factors for scaled math of clocks
+ * @mult:	pointer to mult variable
+ * @shift:	pointer to shift variable
+ * @from:	frequency to convert from
+ * @to:		frequency to convert to
+ * @maxsec:	guaranteed runtime conversion range in seconds
+ *
+ * The function evaluates the shift/mult pair for the scaled math
+ * operations of clocksources and clockevents.
+ *
+ * @to and @from are frequency values in HZ. For clock sources @to is
+ * NSEC_PER_SEC == 1GHz and @from is the counter frequency. For clock
+ * event @to is the counter frequency and @from is NSEC_PER_SEC.
+ *
+ * The @maxsec conversion range argument controls the time frame in
+ * seconds which must be covered by the runtime conversion with the
+ * calculated mult and shift factors. This guarantees that no 64bit
+ * overflow happens when the input value of the conversion is
+ * multiplied with the calculated mult factor. Larger ranges may
+ * reduce the conversion accuracy by choosing smaller mult and shift
+ * factors.
+ */
+void
+clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 maxsec)
+{
+	u64 tmp;
+	u32 sft, sftacc= 32;
+
+	/*
+	 * Calculate the shift factor which is limiting the conversion
+	 * range:
+	 */
+	tmp = ((u64)maxsec * from) >> 32;
+	while (tmp) {
+		tmp >>=1;
+		sftacc--;
+	}
+
+	/*
+	 * Find the conversion shift/mult pair which has the best
+	 * accuracy and fits the maxsec conversion range:
+	 */
+	for (sft = 32; sft > 0; sft--) {
+		tmp = (u64) to << sft;
+		tmp += from / 2;
+		do_div(tmp, from);
+		if ((tmp >> sftacc) == 0)
+			break;
+	}
+	*mult = tmp;
+	*shift = sft;
+}
+EXPORT_SYMBOL_GPL(clocks_calc_mult_shift);
+
+/*[Clocksource internal variables]---------
+ * curr_clocksource:
+ *	currently selected clocksource.
+ * suspend_clocksource:
+ *	used to calculate the suspend time.
+ * clocksource_list:
+ *	linked list with the registered clocksources
+ * clocksource_mutex:
+ *	protects manipulations to curr_clocksource and the clocksource_list
+ * override_name:
+ *	Name of the user-specified clocksource.
+ */
+static struct clocksource *curr_clocksource;
+static struct clocksource *suspend_clocksource;
+static LIST_HEAD(clocksource_list);
+static DEFINE_MUTEX(clocksource_mutex);
+static char override_name[CS_NAME_LEN];
+static int finished_booting;
+static u64 suspend_start;
+
+/*
+ * Threshold: 0.0312s, when doubled: 0.0625s.
+ * Also a default for cs->uncertainty_margin when registering clocks.
+ */
+#define WATCHDOG_THRESHOLD (NSEC_PER_SEC >> 5)
+
+/*
+ * Maximum permissible delay between two readouts of the watchdog
+ * clocksource surrounding a read of the clocksource being validated.
+ * This delay could be due to SMIs, NMIs, or to VCPU preemptions.  Used as
+ * a lower bound for cs->uncertainty_margin values when registering clocks.
+ */
+#ifdef CONFIG_CLOCKSOURCE_WATCHDOG_MAX_SKEW_US
+#define MAX_SKEW_USEC	CONFIG_CLOCKSOURCE_WATCHDOG_MAX_SKEW_US
+#else
+#define MAX_SKEW_USEC	100
+#endif
+
+#define WATCHDOG_MAX_SKEW (MAX_SKEW_USEC * NSEC_PER_USEC)
+
+#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
+static void clocksource_watchdog_work(struct work_struct *work);
+static void clocksource_select(void);
+
+static LIST_HEAD(watchdog_list);
+static struct clocksource *watchdog;
+static struct timer_list watchdog_timer;
+static DECLARE_WORK(watchdog_work, clocksource_watchdog_work);
+static DEFINE_SPINLOCK(watchdog_lock);
+static int watchdog_running;
+static atomic_t watchdog_reset_pending;
+
+static inline void clocksource_watchdog_lock(unsigned long *flags)
+{
+	spin_lock_irqsave(&watchdog_lock, *flags);
+}
+
+static inline void clocksource_watchdog_unlock(unsigned long *flags)
+{
+	spin_unlock_irqrestore(&watchdog_lock, *flags);
+}
+
+static int clocksource_watchdog_kthread(void *data);
+static void __clocksource_change_rating(struct clocksource *cs, int rating);
+
+/*
+ * Interval: 0.5sec.
+ */
+#define WATCHDOG_INTERVAL (HZ >> 1)
+
+static void clocksource_watchdog_work(struct work_struct *work)
+{
+	/*
+	 * We cannot directly run clocksource_watchdog_kthread() here, because
+	 * clocksource_select() calls timekeeping_notify() which uses
+	 * stop_machine(). One cannot use stop_machine() from a workqueue() due
+	 * lock inversions wrt CPU hotplug.
+	 *
+	 * Also, we only ever run this work once or twice during the lifetime
+	 * of the kernel, so there is no point in creating a more permanent
+	 * kthread for this.
+	 *
+	 * If kthread_run fails the next watchdog scan over the
+	 * watchdog_list will find the unstable clock again.
+	 */
+	kthread_run(clocksource_watchdog_kthread, NULL, "kwatchdog");
+}
+
+static void __clocksource_unstable(struct clocksource *cs)
+{
+	cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG);
+	cs->flags |= CLOCK_SOURCE_UNSTABLE;
+
+	/*
+	 * If the clocksource is registered clocksource_watchdog_kthread() will
+	 * re-rate and re-select.
+	 */
+	if (list_empty(&cs->list)) {
+		cs->rating = 0;
+		return;
+	}
+
+	if (cs->mark_unstable)
+		cs->mark_unstable(cs);
+
+	/* kick clocksource_watchdog_kthread() */
+	if (finished_booting)
+		schedule_work(&watchdog_work);
+}
+
+/**
+ * clocksource_mark_unstable - mark clocksource unstable via watchdog
+ * @cs:		clocksource to be marked unstable
+ *
+ * This function is called by the x86 TSC code to mark clocksources as unstable;
+ * it defers demotion and re-selection to a kthread.
+ */
+void clocksource_mark_unstable(struct clocksource *cs)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&watchdog_lock, flags);
+	if (!(cs->flags & CLOCK_SOURCE_UNSTABLE)) {
+		if (!list_empty(&cs->list) && list_empty(&cs->wd_list))
+			list_add(&cs->wd_list, &watchdog_list);
+		__clocksource_unstable(cs);
+	}
+	spin_unlock_irqrestore(&watchdog_lock, flags);
+}
+
+ulong max_cswd_read_retries = 2;
+module_param(max_cswd_read_retries, ulong, 0644);
+EXPORT_SYMBOL_GPL(max_cswd_read_retries);
+static int verify_n_cpus = 8;
+module_param(verify_n_cpus, int, 0644);
+
+enum wd_read_status {
+	WD_READ_SUCCESS,
+	WD_READ_UNSTABLE,
+	WD_READ_SKIP
+};
+
+static enum wd_read_status cs_watchdog_read(struct clocksource *cs, u64 *csnow, u64 *wdnow)
+{
+	unsigned int nretries;
+	u64 wd_end, wd_end2, wd_delta;
+	int64_t wd_delay, wd_seq_delay;
+
+	for (nretries = 0; nretries <= max_cswd_read_retries; nretries++) {
+		local_irq_disable();
+		*wdnow = watchdog->read(watchdog);
+		*csnow = cs->read(cs);
+		wd_end = watchdog->read(watchdog);
+		wd_end2 = watchdog->read(watchdog);
+		local_irq_enable();
+
+		wd_delta = clocksource_delta(wd_end, *wdnow, watchdog->mask);
+		wd_delay = clocksource_cyc2ns(wd_delta, watchdog->mult,
+					      watchdog->shift);
+		if (wd_delay <= WATCHDOG_MAX_SKEW) {
+			if (nretries > 1 || nretries >= max_cswd_read_retries) {
+				pr_warn("timekeeping watchdog on CPU%d: %s retried %d times before success\n",
+					smp_processor_id(), watchdog->name, nretries);
+			}
+			return WD_READ_SUCCESS;
+		}
+
+		/*
+		 * Now compute delay in consecutive watchdog read to see if
+		 * there is too much external interferences that cause
+		 * significant delay in reading both clocksource and watchdog.
+		 *
+		 * If consecutive WD read-back delay > WATCHDOG_MAX_SKEW/2,
+		 * report system busy, reinit the watchdog and skip the current
+		 * watchdog test.
+		 */
+		wd_delta = clocksource_delta(wd_end2, wd_end, watchdog->mask);
+		wd_seq_delay = clocksource_cyc2ns(wd_delta, watchdog->mult, watchdog->shift);
+		if (wd_seq_delay > WATCHDOG_MAX_SKEW/2)
+			goto skip_test;
+	}
+
+	pr_warn("timekeeping watchdog on CPU%d: %s read-back delay of %lldns, attempt %d, marking unstable\n",
+		smp_processor_id(), watchdog->name, wd_delay, nretries);
+	return WD_READ_UNSTABLE;
+
+skip_test:
+	pr_info("timekeeping watchdog on CPU%d: %s wd-wd read-back delay of %lldns\n",
+		smp_processor_id(), watchdog->name, wd_seq_delay);
+	pr_info("wd-%s-wd read-back delay of %lldns, clock-skew test skipped!\n",
+		cs->name, wd_delay);
+	return WD_READ_SKIP;
+}
+
+static u64 csnow_mid;
+static cpumask_t cpus_ahead;
+static cpumask_t cpus_behind;
+static cpumask_t cpus_chosen;
+
+static void clocksource_verify_choose_cpus(void)
+{
+	int cpu, i, n = verify_n_cpus;
+
+	if (n < 0) {
+		/* Check all of the CPUs. */
+		cpumask_copy(&cpus_chosen, cpu_online_mask);
+		cpumask_clear_cpu(smp_processor_id(), &cpus_chosen);
+		return;
+	}
+
+	/* If no checking desired, or no other CPU to check, leave. */
+	cpumask_clear(&cpus_chosen);
+	if (n == 0 || num_online_cpus() <= 1)
+		return;
+
+	/* Make sure to select at least one CPU other than the current CPU. */
+	cpu = cpumask_first(cpu_online_mask);
+	if (cpu == smp_processor_id())
+		cpu = cpumask_next(cpu, cpu_online_mask);
+	if (WARN_ON_ONCE(cpu >= nr_cpu_ids))
+		return;
+	cpumask_set_cpu(cpu, &cpus_chosen);
+
+	/* Force a sane value for the boot parameter. */
+	if (n > nr_cpu_ids)
+		n = nr_cpu_ids;
+
+	/*
+	 * Randomly select the specified number of CPUs.  If the same
+	 * CPU is selected multiple times, that CPU is checked only once,
+	 * and no replacement CPU is selected.  This gracefully handles
+	 * situations where verify_n_cpus is greater than the number of
+	 * CPUs that are currently online.
+	 */
+	for (i = 1; i < n; i++) {
+		cpu = prandom_u32_max(nr_cpu_ids);
+		cpu = cpumask_next(cpu - 1, cpu_online_mask);
+		if (cpu >= nr_cpu_ids)
+			cpu = cpumask_first(cpu_online_mask);
+		if (!WARN_ON_ONCE(cpu >= nr_cpu_ids))
+			cpumask_set_cpu(cpu, &cpus_chosen);
+	}
+
+	/* Don't verify ourselves. */
+	cpumask_clear_cpu(smp_processor_id(), &cpus_chosen);
+}
+
+static void clocksource_verify_one_cpu(void *csin)
+{
+	struct clocksource *cs = (struct clocksource *)csin;
+
+	csnow_mid = cs->read(cs);
+}
+
+void clocksource_verify_percpu(struct clocksource *cs)
+{
+	int64_t cs_nsec, cs_nsec_max = 0, cs_nsec_min = LLONG_MAX;
+	u64 csnow_begin, csnow_end;
+	int cpu, testcpu;
+	s64 delta;
+
+	if (verify_n_cpus == 0)
+		return;
+	cpumask_clear(&cpus_ahead);
+	cpumask_clear(&cpus_behind);
+	cpus_read_lock();
+	preempt_disable();
+	clocksource_verify_choose_cpus();
+	if (cpumask_empty(&cpus_chosen)) {
+		preempt_enable();
+		cpus_read_unlock();
+		pr_warn("Not enough CPUs to check clocksource '%s'.\n", cs->name);
+		return;
+	}
+	testcpu = smp_processor_id();
+	pr_warn("Checking clocksource %s synchronization from CPU %d to CPUs %*pbl.\n", cs->name, testcpu, cpumask_pr_args(&cpus_chosen));
+	for_each_cpu(cpu, &cpus_chosen) {
+		if (cpu == testcpu)
+			continue;
+		csnow_begin = cs->read(cs);
+		smp_call_function_single(cpu, clocksource_verify_one_cpu, cs, 1);
+		csnow_end = cs->read(cs);
+		delta = (s64)((csnow_mid - csnow_begin) & cs->mask);
+		if (delta < 0)
+			cpumask_set_cpu(cpu, &cpus_behind);
+		delta = (csnow_end - csnow_mid) & cs->mask;
+		if (delta < 0)
+			cpumask_set_cpu(cpu, &cpus_ahead);
+		delta = clocksource_delta(csnow_end, csnow_begin, cs->mask);
+		cs_nsec = clocksource_cyc2ns(delta, cs->mult, cs->shift);
+		if (cs_nsec > cs_nsec_max)
+			cs_nsec_max = cs_nsec;
+		if (cs_nsec < cs_nsec_min)
+			cs_nsec_min = cs_nsec;
+	}
+	preempt_enable();
+	cpus_read_unlock();
+	if (!cpumask_empty(&cpus_ahead))
+		pr_warn("        CPUs %*pbl ahead of CPU %d for clocksource %s.\n",
+			cpumask_pr_args(&cpus_ahead), testcpu, cs->name);
+	if (!cpumask_empty(&cpus_behind))
+		pr_warn("        CPUs %*pbl behind CPU %d for clocksource %s.\n",
+			cpumask_pr_args(&cpus_behind), testcpu, cs->name);
+	if (!cpumask_empty(&cpus_ahead) || !cpumask_empty(&cpus_behind))
+		pr_warn("        CPU %d check durations %lldns - %lldns for clocksource %s.\n",
+			testcpu, cs_nsec_min, cs_nsec_max, cs->name);
+}
+EXPORT_SYMBOL_GPL(clocksource_verify_percpu);
+
+static inline void clocksource_reset_watchdog(void)
+{
+	struct clocksource *cs;
+
+	list_for_each_entry(cs, &watchdog_list, wd_list)
+		cs->flags &= ~CLOCK_SOURCE_WATCHDOG;
+}
+
+
+static void clocksource_watchdog(struct timer_list *unused)
+{
+	u64 csnow, wdnow, cslast, wdlast, delta;
+	int next_cpu, reset_pending;
+	int64_t wd_nsec, cs_nsec;
+	struct clocksource *cs;
+	enum wd_read_status read_ret;
+	unsigned long extra_wait = 0;
+	u32 md;
+
+	spin_lock(&watchdog_lock);
+	if (!watchdog_running)
+		goto out;
+
+	reset_pending = atomic_read(&watchdog_reset_pending);
+
+	list_for_each_entry(cs, &watchdog_list, wd_list) {
+
+		/* Clocksource already marked unstable? */
+		if (cs->flags & CLOCK_SOURCE_UNSTABLE) {
+			if (finished_booting)
+				schedule_work(&watchdog_work);
+			continue;
+		}
+
+		read_ret = cs_watchdog_read(cs, &csnow, &wdnow);
+
+		if (read_ret == WD_READ_UNSTABLE) {
+			/* Clock readout unreliable, so give it up. */
+			__clocksource_unstable(cs);
+			continue;
+		}
+
+		/*
+		 * When WD_READ_SKIP is returned, it means the system is likely
+		 * under very heavy load, where the latency of reading
+		 * watchdog/clocksource is very big, and affect the accuracy of
+		 * watchdog check. So give system some space and suspend the
+		 * watchdog check for 5 minutes.
+		 */
+		if (read_ret == WD_READ_SKIP) {
+			/*
+			 * As the watchdog timer will be suspended, and
+			 * cs->last could keep unchanged for 5 minutes, reset
+			 * the counters.
+			 */
+			clocksource_reset_watchdog();
+			extra_wait = HZ * 300;
+			break;
+		}
+
+		/* Clocksource initialized ? */
+		if (!(cs->flags & CLOCK_SOURCE_WATCHDOG) ||
+		    atomic_read(&watchdog_reset_pending)) {
+			cs->flags |= CLOCK_SOURCE_WATCHDOG;
+			cs->wd_last = wdnow;
+			cs->cs_last = csnow;
+			continue;
+		}
+
+		delta = clocksource_delta(wdnow, cs->wd_last, watchdog->mask);
+		wd_nsec = clocksource_cyc2ns(delta, watchdog->mult,
+					     watchdog->shift);
+
+		delta = clocksource_delta(csnow, cs->cs_last, cs->mask);
+		cs_nsec = clocksource_cyc2ns(delta, cs->mult, cs->shift);
+		wdlast = cs->wd_last; /* save these in case we print them */
+		cslast = cs->cs_last;
+		cs->cs_last = csnow;
+		cs->wd_last = wdnow;
+
+		if (atomic_read(&watchdog_reset_pending))
+			continue;
+
+		/* Check the deviation from the watchdog clocksource. */
+		md = cs->uncertainty_margin + watchdog->uncertainty_margin;
+		if (abs(cs_nsec - wd_nsec) > md) {
+			pr_warn("timekeeping watchdog on CPU%d: Marking clocksource '%s' as unstable because the skew is too large:\n",
+				smp_processor_id(), cs->name);
+			pr_warn("                      '%s' wd_nsec: %lld wd_now: %llx wd_last: %llx mask: %llx\n",
+				watchdog->name, wd_nsec, wdnow, wdlast, watchdog->mask);
+			pr_warn("                      '%s' cs_nsec: %lld cs_now: %llx cs_last: %llx mask: %llx\n",
+				cs->name, cs_nsec, csnow, cslast, cs->mask);
+			if (curr_clocksource == cs)
+				pr_warn("                      '%s' is current clocksource.\n", cs->name);
+			else if (curr_clocksource)
+				pr_warn("                      '%s' (not '%s') is current clocksource.\n", curr_clocksource->name, cs->name);
+			else
+				pr_warn("                      No current clocksource.\n");
+			__clocksource_unstable(cs);
+			continue;
+		}
+
+		if (cs == curr_clocksource && cs->tick_stable)
+			cs->tick_stable(cs);
+
+		if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) &&
+		    (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) &&
+		    (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) {
+			/* Mark it valid for high-res. */
+			cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
+
+			/*
+			 * clocksource_done_booting() will sort it if
+			 * finished_booting is not set yet.
+			 */
+			if (!finished_booting)
+				continue;
+
+			/*
+			 * If this is not the current clocksource let
+			 * the watchdog thread reselect it. Due to the
+			 * change to high res this clocksource might
+			 * be preferred now. If it is the current
+			 * clocksource let the tick code know about
+			 * that change.
+			 */
+			if (cs != curr_clocksource) {
+				cs->flags |= CLOCK_SOURCE_RESELECT;
+				schedule_work(&watchdog_work);
+			} else {
+				tick_clock_notify();
+			}
+		}
+	}
+
+	/*
+	 * We only clear the watchdog_reset_pending, when we did a
+	 * full cycle through all clocksources.
+	 */
+	if (reset_pending)
+		atomic_dec(&watchdog_reset_pending);
+
+	/*
+	 * Cycle through CPUs to check if the CPUs stay synchronized
+	 * to each other.
+	 */
+	next_cpu = cpumask_next(raw_smp_processor_id(), cpu_online_mask);
+	if (next_cpu >= nr_cpu_ids)
+		next_cpu = cpumask_first(cpu_online_mask);
+
+	/*
+	 * Arm timer if not already pending: could race with concurrent
+	 * pair clocksource_stop_watchdog() clocksource_start_watchdog().
+	 */
+	if (!timer_pending(&watchdog_timer)) {
+		watchdog_timer.expires += WATCHDOG_INTERVAL + extra_wait;
+		add_timer_on(&watchdog_timer, next_cpu);
+	}
+out:
+	spin_unlock(&watchdog_lock);
+}
+
+static inline void clocksource_start_watchdog(void)
+{
+	if (watchdog_running || !watchdog || list_empty(&watchdog_list))
+		return;
+	timer_setup(&watchdog_timer, clocksource_watchdog, 0);
+	watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
+	add_timer_on(&watchdog_timer, cpumask_first(cpu_online_mask));
+	watchdog_running = 1;
+}
+
+static inline void clocksource_stop_watchdog(void)
+{
+	if (!watchdog_running || (watchdog && !list_empty(&watchdog_list)))
+		return;
+	del_timer(&watchdog_timer);
+	watchdog_running = 0;
+}
+
+static void clocksource_resume_watchdog(void)
+{
+	atomic_inc(&watchdog_reset_pending);
+}
+
+static void clocksource_enqueue_watchdog(struct clocksource *cs)
+{
+	INIT_LIST_HEAD(&cs->wd_list);
+
+	if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) {
+		/* cs is a clocksource to be watched. */
+		list_add(&cs->wd_list, &watchdog_list);
+		cs->flags &= ~CLOCK_SOURCE_WATCHDOG;
+	} else {
+		/* cs is a watchdog. */
+		if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
+			cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
+	}
+}
+
+static void clocksource_select_watchdog(bool fallback)
+{
+	struct clocksource *cs, *old_wd;
+	unsigned long flags;
+
+	spin_lock_irqsave(&watchdog_lock, flags);
+	/* save current watchdog */
+	old_wd = watchdog;
+	if (fallback)
+		watchdog = NULL;
+
+	list_for_each_entry(cs, &clocksource_list, list) {
+		/* cs is a clocksource to be watched. */
+		if (cs->flags & CLOCK_SOURCE_MUST_VERIFY)
+			continue;
+
+		/* Skip current if we were requested for a fallback. */
+		if (fallback && cs == old_wd)
+			continue;
+
+		/* Pick the best watchdog. */
+		if (!watchdog || cs->rating > watchdog->rating)
+			watchdog = cs;
+	}
+	/* If we failed to find a fallback restore the old one. */
+	if (!watchdog)
+		watchdog = old_wd;
+
+	/* If we changed the watchdog we need to reset cycles. */
+	if (watchdog != old_wd)
+		clocksource_reset_watchdog();
+
+	/* Check if the watchdog timer needs to be started. */
+	clocksource_start_watchdog();
+	spin_unlock_irqrestore(&watchdog_lock, flags);
+}
+
+static void clocksource_dequeue_watchdog(struct clocksource *cs)
+{
+	if (cs != watchdog) {
+		if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) {
+			/* cs is a watched clocksource. */
+			list_del_init(&cs->wd_list);
+			/* Check if the watchdog timer needs to be stopped. */
+			clocksource_stop_watchdog();
+		}
+	}
+}
+
+static int __clocksource_watchdog_kthread(void)
+{
+	struct clocksource *cs, *tmp;
+	unsigned long flags;
+	int select = 0;
+
+	/* Do any required per-CPU skew verification. */
+	if (curr_clocksource &&
+	    curr_clocksource->flags & CLOCK_SOURCE_UNSTABLE &&
+	    curr_clocksource->flags & CLOCK_SOURCE_VERIFY_PERCPU)
+		clocksource_verify_percpu(curr_clocksource);
+
+	spin_lock_irqsave(&watchdog_lock, flags);
+	list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) {
+		if (cs->flags & CLOCK_SOURCE_UNSTABLE) {
+			list_del_init(&cs->wd_list);
+			__clocksource_change_rating(cs, 0);
+			select = 1;
+		}
+		if (cs->flags & CLOCK_SOURCE_RESELECT) {
+			cs->flags &= ~CLOCK_SOURCE_RESELECT;
+			select = 1;
+		}
+	}
+	/* Check if the watchdog timer needs to be stopped. */
+	clocksource_stop_watchdog();
+	spin_unlock_irqrestore(&watchdog_lock, flags);
+
+	return select;
+}
+
+static int clocksource_watchdog_kthread(void *data)
+{
+	mutex_lock(&clocksource_mutex);
+	if (__clocksource_watchdog_kthread())
+		clocksource_select();
+	mutex_unlock(&clocksource_mutex);
+	return 0;
+}
+
+static bool clocksource_is_watchdog(struct clocksource *cs)
+{
+	return cs == watchdog;
+}
+
+#else /* CONFIG_CLOCKSOURCE_WATCHDOG */
+
+static void clocksource_enqueue_watchdog(struct clocksource *cs)
+{
+	if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
+		cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
+}
+
+static void clocksource_select_watchdog(bool fallback) { }
+static inline void clocksource_dequeue_watchdog(struct clocksource *cs) { }
+static inline void clocksource_resume_watchdog(void) { }
+static inline int __clocksource_watchdog_kthread(void) { return 0; }
+static bool clocksource_is_watchdog(struct clocksource *cs) { return false; }
+void clocksource_mark_unstable(struct clocksource *cs) { }
+
+static inline void clocksource_watchdog_lock(unsigned long *flags) { }
+static inline void clocksource_watchdog_unlock(unsigned long *flags) { }
+
+#endif /* CONFIG_CLOCKSOURCE_WATCHDOG */
+
+static bool clocksource_is_suspend(struct clocksource *cs)
+{
+	return cs == suspend_clocksource;
+}
+
+static void __clocksource_suspend_select(struct clocksource *cs)
+{
+	/*
+	 * Skip the clocksource which will be stopped in suspend state.
+	 */
+	if (!(cs->flags & CLOCK_SOURCE_SUSPEND_NONSTOP))
+		return;
+
+	/*
+	 * The nonstop clocksource can be selected as the suspend clocksource to
+	 * calculate the suspend time, so it should not supply suspend/resume
+	 * interfaces to suspend the nonstop clocksource when system suspends.
+	 */
+	if (cs->suspend || cs->resume) {
+		pr_warn("Nonstop clocksource %s should not supply suspend/resume interfaces\n",
+			cs->name);
+	}
+
+	/* Pick the best rating. */
+	if (!suspend_clocksource || cs->rating > suspend_clocksource->rating)
+		suspend_clocksource = cs;
+}
+
+/**
+ * clocksource_suspend_select - Select the best clocksource for suspend timing
+ * @fallback:	if select a fallback clocksource
+ */
+static void clocksource_suspend_select(bool fallback)
+{
+	struct clocksource *cs, *old_suspend;
+
+	old_suspend = suspend_clocksource;
+	if (fallback)
+		suspend_clocksource = NULL;
+
+	list_for_each_entry(cs, &clocksource_list, list) {
+		/* Skip current if we were requested for a fallback. */
+		if (fallback && cs == old_suspend)
+			continue;
+
+		__clocksource_suspend_select(cs);
+	}
+}
+
+/**
+ * clocksource_start_suspend_timing - Start measuring the suspend timing
+ * @cs:			current clocksource from timekeeping
+ * @start_cycles:	current cycles from timekeeping
+ *
+ * This function will save the start cycle values of suspend timer to calculate
+ * the suspend time when resuming system.
+ *
+ * This function is called late in the suspend process from timekeeping_suspend(),
+ * that means processes are frozen, non-boot cpus and interrupts are disabled
+ * now. It is therefore possible to start the suspend timer without taking the
+ * clocksource mutex.
+ */
+void clocksource_start_suspend_timing(struct clocksource *cs, u64 start_cycles)
+{
+	if (!suspend_clocksource)
+		return;
+
+	/*
+	 * If current clocksource is the suspend timer, we should use the
+	 * tkr_mono.cycle_last value as suspend_start to avoid same reading
+	 * from suspend timer.
+	 */
+	if (clocksource_is_suspend(cs)) {
+		suspend_start = start_cycles;
+		return;
+	}
+
+	if (suspend_clocksource->enable &&
+	    suspend_clocksource->enable(suspend_clocksource)) {
+		pr_warn_once("Failed to enable the non-suspend-able clocksource.\n");
+		return;
+	}
+
+	suspend_start = suspend_clocksource->read(suspend_clocksource);
+}
+
+/**
+ * clocksource_stop_suspend_timing - Stop measuring the suspend timing
+ * @cs:		current clocksource from timekeeping
+ * @cycle_now:	current cycles from timekeeping
+ *
+ * This function will calculate the suspend time from suspend timer.
+ *
+ * Returns nanoseconds since suspend started, 0 if no usable suspend clocksource.
+ *
+ * This function is called early in the resume process from timekeeping_resume(),
+ * that means there is only one cpu, no processes are running and the interrupts
+ * are disabled. It is therefore possible to stop the suspend timer without
+ * taking the clocksource mutex.
+ */
+u64 clocksource_stop_suspend_timing(struct clocksource *cs, u64 cycle_now)
+{
+	u64 now, delta, nsec = 0;
+
+	if (!suspend_clocksource)
+		return 0;
+
+	/*
+	 * If current clocksource is the suspend timer, we should use the
+	 * tkr_mono.cycle_last value from timekeeping as current cycle to
+	 * avoid same reading from suspend timer.
+	 */
+	if (clocksource_is_suspend(cs))
+		now = cycle_now;
+	else
+		now = suspend_clocksource->read(suspend_clocksource);
+
+	if (now > suspend_start) {
+		delta = clocksource_delta(now, suspend_start,
+					  suspend_clocksource->mask);
+		nsec = mul_u64_u32_shr(delta, suspend_clocksource->mult,
+				       suspend_clocksource->shift);
+	}
+
+	/*
+	 * Disable the suspend timer to save power if current clocksource is
+	 * not the suspend timer.
+	 */
+	if (!clocksource_is_suspend(cs) && suspend_clocksource->disable)
+		suspend_clocksource->disable(suspend_clocksource);
+
+	return nsec;
+}
+
+/**
+ * clocksource_suspend - suspend the clocksource(s)
+ */
+void clocksource_suspend(void)
+{
+	struct clocksource *cs;
+
+	list_for_each_entry_reverse(cs, &clocksource_list, list)
+		if (cs->suspend)
+			cs->suspend(cs);
+}
+
+/**
+ * clocksource_resume - resume the clocksource(s)
+ */
+void clocksource_resume(void)
+{
+	struct clocksource *cs;
+
+	list_for_each_entry(cs, &clocksource_list, list)
+		if (cs->resume)
+			cs->resume(cs);
+
+	clocksource_resume_watchdog();
+}
+
+/**
+ * clocksource_touch_watchdog - Update watchdog
+ *
+ * Update the watchdog after exception contexts such as kgdb so as not
+ * to incorrectly trip the watchdog. This might fail when the kernel
+ * was stopped in code which holds watchdog_lock.
+ */
+void clocksource_touch_watchdog(void)
+{
+	clocksource_resume_watchdog();
+}
+
+/**
+ * clocksource_max_adjustment- Returns max adjustment amount
+ * @cs:         Pointer to clocksource
+ *
+ */
+static u32 clocksource_max_adjustment(struct clocksource *cs)
+{
+	u64 ret;
+	/*
+	 * We won't try to correct for more than 11% adjustments (110,000 ppm),
+	 */
+	ret = (u64)cs->mult * 11;
+	do_div(ret,100);
+	return (u32)ret;
+}
+
+/**
+ * clocks_calc_max_nsecs - Returns maximum nanoseconds that can be converted
+ * @mult:	cycle to nanosecond multiplier
+ * @shift:	cycle to nanosecond divisor (power of two)
+ * @maxadj:	maximum adjustment value to mult (~11%)
+ * @mask:	bitmask for two's complement subtraction of non 64 bit counters
+ * @max_cyc:	maximum cycle value before potential overflow (does not include
+ *		any safety margin)
+ *
+ * NOTE: This function includes a safety margin of 50%, in other words, we
+ * return half the number of nanoseconds the hardware counter can technically
+ * cover. This is done so that we can potentially detect problems caused by
+ * delayed timers or bad hardware, which might result in time intervals that
+ * are larger than what the math used can handle without overflows.
+ */
+u64 clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask, u64 *max_cyc)
+{
+	u64 max_nsecs, max_cycles;
+
+	/*
+	 * Calculate the maximum number of cycles that we can pass to the
+	 * cyc2ns() function without overflowing a 64-bit result.
+	 */
+	max_cycles = ULLONG_MAX;
+	do_div(max_cycles, mult+maxadj);
+
+	/*
+	 * The actual maximum number of cycles we can defer the clocksource is
+	 * determined by the minimum of max_cycles and mask.
+	 * Note: Here we subtract the maxadj to make sure we don't sleep for
+	 * too long if there's a large negative adjustment.
+	 */
+	max_cycles = min(max_cycles, mask);
+	max_nsecs = clocksource_cyc2ns(max_cycles, mult - maxadj, shift);
+
+	/* return the max_cycles value as well if requested */
+	if (max_cyc)
+		*max_cyc = max_cycles;
+
+	/* Return 50% of the actual maximum, so we can detect bad values */
+	max_nsecs >>= 1;
+
+	return max_nsecs;
+}
+
+/**
+ * clocksource_update_max_deferment - Updates the clocksource max_idle_ns & max_cycles
+ * @cs:         Pointer to clocksource to be updated
+ *
+ */
+static inline void clocksource_update_max_deferment(struct clocksource *cs)
+{
+	cs->max_idle_ns = clocks_calc_max_nsecs(cs->mult, cs->shift,
+						cs->maxadj, cs->mask,
+						&cs->max_cycles);
+}
+
+static struct clocksource *clocksource_find_best(bool oneshot, bool skipcur)
+{
+	struct clocksource *cs;
+
+	if (!finished_booting || list_empty(&clocksource_list))
+		return NULL;
+
+	/*
+	 * We pick the clocksource with the highest rating. If oneshot
+	 * mode is active, we pick the highres valid clocksource with
+	 * the best rating.
+	 */
+	list_for_each_entry(cs, &clocksource_list, list) {
+		if (skipcur && cs == curr_clocksource)
+			continue;
+		if (oneshot && !(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES))
+			continue;
+		return cs;
+	}
+	return NULL;
+}
+
+static void __clocksource_select(bool skipcur)
+{
+	bool oneshot = tick_oneshot_mode_active();
+	struct clocksource *best, *cs;
+
+	/* Find the best suitable clocksource */
+	best = clocksource_find_best(oneshot, skipcur);
+	if (!best)
+		return;
+
+	if (!strlen(override_name))
+		goto found;
+
+	/* Check for the override clocksource. */
+	list_for_each_entry(cs, &clocksource_list, list) {
+		if (skipcur && cs == curr_clocksource)
+			continue;
+		if (strcmp(cs->name, override_name) != 0)
+			continue;
+		/*
+		 * Check to make sure we don't switch to a non-highres
+		 * capable clocksource if the tick code is in oneshot
+		 * mode (highres or nohz)
+		 */
+		if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) && oneshot) {
+			/* Override clocksource cannot be used. */
+			if (cs->flags & CLOCK_SOURCE_UNSTABLE) {
+				pr_warn("Override clocksource %s is unstable and not HRT compatible - cannot switch while in HRT/NOHZ mode\n",
+					cs->name);
+				override_name[0] = 0;
+			} else {
+				/*
+				 * The override cannot be currently verified.
+				 * Deferring to let the watchdog check.
+				 */
+				pr_info("Override clocksource %s is not currently HRT compatible - deferring\n",
+					cs->name);
+			}
+		} else
+			/* Override clocksource can be used. */
+			best = cs;
+		break;
+	}
+
+found:
+	if (curr_clocksource != best && !timekeeping_notify(best)) {
+		pr_info("Switched to clocksource %s\n", best->name);
+		curr_clocksource = best;
+	}
+}
+
+/**
+ * clocksource_select - Select the best clocksource available
+ *
+ * Private function. Must hold clocksource_mutex when called.
+ *
+ * Select the clocksource with the best rating, or the clocksource,
+ * which is selected by userspace override.
+ */
+static void clocksource_select(void)
+{
+	__clocksource_select(false);
+}
+
+static void clocksource_select_fallback(void)
+{
+	__clocksource_select(true);
+}
+
+/*
+ * clocksource_done_booting - Called near the end of core bootup
+ *
+ * Hack to avoid lots of clocksource churn at boot time.
+ * We use fs_initcall because we want this to start before
+ * device_initcall but after subsys_initcall.
+ */
+static int __init clocksource_done_booting(void)
+{
+	mutex_lock(&clocksource_mutex);
+	curr_clocksource = clocksource_default_clock();
+	finished_booting = 1;
+	/*
+	 * Run the watchdog first to eliminate unstable clock sources
+	 */
+	__clocksource_watchdog_kthread();
+	clocksource_select();
+	mutex_unlock(&clocksource_mutex);
+	return 0;
+}
+fs_initcall(clocksource_done_booting);
+
+/*
+ * Enqueue the clocksource sorted by rating
+ */
+static void clocksource_enqueue(struct clocksource *cs)
+{
+	struct list_head *entry = &clocksource_list;
+	struct clocksource *tmp;
+
+	list_for_each_entry(tmp, &clocksource_list, list) {
+		/* Keep track of the place, where to insert */
+		if (tmp->rating < cs->rating)
+			break;
+		entry = &tmp->list;
+	}
+	list_add(&cs->list, entry);
+}
+
+/**
+ * __clocksource_update_freq_scale - Used update clocksource with new freq
+ * @cs:		clocksource to be registered
+ * @scale:	Scale factor multiplied against freq to get clocksource hz
+ * @freq:	clocksource frequency (cycles per second) divided by scale
+ *
+ * This should only be called from the clocksource->enable() method.
+ *
+ * This *SHOULD NOT* be called directly! Please use the
+ * __clocksource_update_freq_hz() or __clocksource_update_freq_khz() helper
+ * functions.
+ */
+void __clocksource_update_freq_scale(struct clocksource *cs, u32 scale, u32 freq)
+{
+	u64 sec;
+
+	/*
+	 * Default clocksources are *special* and self-define their mult/shift.
+	 * But, you're not special, so you should specify a freq value.
+	 */
+	if (freq) {
+		/*
+		 * Calc the maximum number of seconds which we can run before
+		 * wrapping around. For clocksources which have a mask > 32-bit
+		 * we need to limit the max sleep time to have a good
+		 * conversion precision. 10 minutes is still a reasonable
+		 * amount. That results in a shift value of 24 for a
+		 * clocksource with mask >= 40-bit and f >= 4GHz. That maps to
+		 * ~ 0.06ppm granularity for NTP.
+		 */
+		sec = cs->mask;
+		do_div(sec, freq);
+		do_div(sec, scale);
+		if (!sec)
+			sec = 1;
+		else if (sec > 600 && cs->mask > UINT_MAX)
+			sec = 600;
+
+		clocks_calc_mult_shift(&cs->mult, &cs->shift, freq,
+				       NSEC_PER_SEC / scale, sec * scale);
+	}
+
+	/*
+	 * If the uncertainty margin is not specified, calculate it.
+	 * If both scale and freq are non-zero, calculate the clock
+	 * period, but bound below at 2*WATCHDOG_MAX_SKEW.  However,
+	 * if either of scale or freq is zero, be very conservative and
+	 * take the tens-of-milliseconds WATCHDOG_THRESHOLD value for the
+	 * uncertainty margin.  Allow stupidly small uncertainty margins
+	 * to be specified by the caller for testing purposes, but warn
+	 * to discourage production use of this capability.
+	 */
+	if (scale && freq && !cs->uncertainty_margin) {
+		cs->uncertainty_margin = NSEC_PER_SEC / (scale * freq);
+		if (cs->uncertainty_margin < 2 * WATCHDOG_MAX_SKEW)
+			cs->uncertainty_margin = 2 * WATCHDOG_MAX_SKEW;
+	} else if (!cs->uncertainty_margin) {
+		cs->uncertainty_margin = WATCHDOG_THRESHOLD;
+	}
+	WARN_ON_ONCE(cs->uncertainty_margin < 2 * WATCHDOG_MAX_SKEW);
+
+	/*
+	 * Ensure clocksources that have large 'mult' values don't overflow
+	 * when adjusted.
+	 */
+	cs->maxadj = clocksource_max_adjustment(cs);
+	while (freq && ((cs->mult + cs->maxadj < cs->mult)
+		|| (cs->mult - cs->maxadj > cs->mult))) {
+		cs->mult >>= 1;
+		cs->shift--;
+		cs->maxadj = clocksource_max_adjustment(cs);
+	}
+
+	/*
+	 * Only warn for *special* clocksources that self-define
+	 * their mult/shift values and don't specify a freq.
+	 */
+	WARN_ONCE(cs->mult + cs->maxadj < cs->mult,
+		"timekeeping: Clocksource %s might overflow on 11%% adjustment\n",
+		cs->name);
+
+	clocksource_update_max_deferment(cs);
+
+	pr_info("%s: mask: 0x%llx max_cycles: 0x%llx, max_idle_ns: %lld ns\n",
+		cs->name, cs->mask, cs->max_cycles, cs->max_idle_ns);
+}
+EXPORT_SYMBOL_GPL(__clocksource_update_freq_scale);
+
+/**
+ * __clocksource_register_scale - Used to install new clocksources
+ * @cs:		clocksource to be registered
+ * @scale:	Scale factor multiplied against freq to get clocksource hz
+ * @freq:	clocksource frequency (cycles per second) divided by scale
+ *
+ * Returns -EBUSY if registration fails, zero otherwise.
+ *
+ * This *SHOULD NOT* be called directly! Please use the
+ * clocksource_register_hz() or clocksource_register_khz helper functions.
+ */
+int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq)
+{
+	unsigned long flags;
+
+	clocksource_arch_init(cs);
+
+	if (WARN_ON_ONCE((unsigned int)cs->id >= CSID_MAX))
+		cs->id = CSID_GENERIC;
+	if (cs->vdso_clock_mode < 0 ||
+	    cs->vdso_clock_mode >= VDSO_CLOCKMODE_MAX) {
+		pr_warn("clocksource %s registered with invalid VDSO mode %d. Disabling VDSO support.\n",
+			cs->name, cs->vdso_clock_mode);
+		cs->vdso_clock_mode = VDSO_CLOCKMODE_NONE;
+	}
+
+	/* Initialize mult/shift and max_idle_ns */
+	__clocksource_update_freq_scale(cs, scale, freq);
+
+	/* Add clocksource to the clocksource list */
+	mutex_lock(&clocksource_mutex);
+
+	clocksource_watchdog_lock(&flags);
+	clocksource_enqueue(cs);
+	clocksource_enqueue_watchdog(cs);
+	clocksource_watchdog_unlock(&flags);
+
+	clocksource_select();
+	clocksource_select_watchdog(false);
+	__clocksource_suspend_select(cs);
+	mutex_unlock(&clocksource_mutex);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__clocksource_register_scale);
+
+static void __clocksource_change_rating(struct clocksource *cs, int rating)
+{
+	list_del(&cs->list);
+	cs->rating = rating;
+	clocksource_enqueue(cs);
+}
+
+/**
+ * clocksource_change_rating - Change the rating of a registered clocksource
+ * @cs:		clocksource to be changed
+ * @rating:	new rating
+ */
+void clocksource_change_rating(struct clocksource *cs, int rating)
+{
+	unsigned long flags;
+
+	mutex_lock(&clocksource_mutex);
+	clocksource_watchdog_lock(&flags);
+	__clocksource_change_rating(cs, rating);
+	clocksource_watchdog_unlock(&flags);
+
+	clocksource_select();
+	clocksource_select_watchdog(false);
+	clocksource_suspend_select(false);
+	mutex_unlock(&clocksource_mutex);
+}
+EXPORT_SYMBOL(clocksource_change_rating);
+
+/*
+ * Unbind clocksource @cs. Called with clocksource_mutex held
+ */
+static int clocksource_unbind(struct clocksource *cs)
+{
+	unsigned long flags;
+
+	if (clocksource_is_watchdog(cs)) {
+		/* Select and try to install a replacement watchdog. */
+		clocksource_select_watchdog(true);
+		if (clocksource_is_watchdog(cs))
+			return -EBUSY;
+	}
+
+	if (cs == curr_clocksource) {
+		/* Select and try to install a replacement clock source */
+		clocksource_select_fallback();
+		if (curr_clocksource == cs)
+			return -EBUSY;
+	}
+
+	if (clocksource_is_suspend(cs)) {
+		/*
+		 * Select and try to install a replacement suspend clocksource.
+		 * If no replacement suspend clocksource, we will just let the
+		 * clocksource go and have no suspend clocksource.
+		 */
+		clocksource_suspend_select(true);
+	}
+
+	clocksource_watchdog_lock(&flags);
+	clocksource_dequeue_watchdog(cs);
+	list_del_init(&cs->list);
+	clocksource_watchdog_unlock(&flags);
+
+	return 0;
+}
+
+/**
+ * clocksource_unregister - remove a registered clocksource
+ * @cs:	clocksource to be unregistered
+ */
+int clocksource_unregister(struct clocksource *cs)
+{
+	int ret = 0;
+
+	mutex_lock(&clocksource_mutex);
+	if (!list_empty(&cs->list))
+		ret = clocksource_unbind(cs);
+	mutex_unlock(&clocksource_mutex);
+	return ret;
+}
+EXPORT_SYMBOL(clocksource_unregister);
+
+#ifdef CONFIG_SYSFS
+/**
+ * current_clocksource_show - sysfs interface for current clocksource
+ * @dev:	unused
+ * @attr:	unused
+ * @buf:	char buffer to be filled with clocksource list
+ *
+ * Provides sysfs interface for listing current clocksource.
+ */
+static ssize_t current_clocksource_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	ssize_t count = 0;
+
+	mutex_lock(&clocksource_mutex);
+	count = snprintf(buf, PAGE_SIZE, "%s\n", curr_clocksource->name);
+	mutex_unlock(&clocksource_mutex);
+
+	return count;
+}
+
+ssize_t sysfs_get_uname(const char *buf, char *dst, size_t cnt)
+{
+	size_t ret = cnt;
+
+	/* strings from sysfs write are not 0 terminated! */
+	if (!cnt || cnt >= CS_NAME_LEN)
+		return -EINVAL;
+
+	/* strip of \n: */
+	if (buf[cnt-1] == '\n')
+		cnt--;
+	if (cnt > 0)
+		memcpy(dst, buf, cnt);
+	dst[cnt] = 0;
+	return ret;
+}
+
+/**
+ * current_clocksource_store - interface for manually overriding clocksource
+ * @dev:	unused
+ * @attr:	unused
+ * @buf:	name of override clocksource
+ * @count:	length of buffer
+ *
+ * Takes input from sysfs interface for manually overriding the default
+ * clocksource selection.
+ */
+static ssize_t current_clocksource_store(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf, size_t count)
+{
+	ssize_t ret;
+
+	mutex_lock(&clocksource_mutex);
+
+	ret = sysfs_get_uname(buf, override_name, count);
+	if (ret >= 0)
+		clocksource_select();
+
+	mutex_unlock(&clocksource_mutex);
+
+	return ret;
+}
+static DEVICE_ATTR_RW(current_clocksource);
+
+/**
+ * unbind_clocksource_store - interface for manually unbinding clocksource
+ * @dev:	unused
+ * @attr:	unused
+ * @buf:	unused
+ * @count:	length of buffer
+ *
+ * Takes input from sysfs interface for manually unbinding a clocksource.
+ */
+static ssize_t unbind_clocksource_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	struct clocksource *cs;
+	char name[CS_NAME_LEN];
+	ssize_t ret;
+
+	ret = sysfs_get_uname(buf, name, count);
+	if (ret < 0)
+		return ret;
+
+	ret = -ENODEV;
+	mutex_lock(&clocksource_mutex);
+	list_for_each_entry(cs, &clocksource_list, list) {
+		if (strcmp(cs->name, name))
+			continue;
+		ret = clocksource_unbind(cs);
+		break;
+	}
+	mutex_unlock(&clocksource_mutex);
+
+	return ret ? ret : count;
+}
+static DEVICE_ATTR_WO(unbind_clocksource);
+
+/**
+ * available_clocksource_show - sysfs interface for listing clocksource
+ * @dev:	unused
+ * @attr:	unused
+ * @buf:	char buffer to be filled with clocksource list
+ *
+ * Provides sysfs interface for listing registered clocksources
+ */
+static ssize_t available_clocksource_show(struct device *dev,
+					  struct device_attribute *attr,
+					  char *buf)
+{
+	struct clocksource *src;
+	ssize_t count = 0;
+
+	mutex_lock(&clocksource_mutex);
+	list_for_each_entry(src, &clocksource_list, list) {
+		/*
+		 * Don't show non-HRES clocksource if the tick code is
+		 * in one shot mode (highres=on or nohz=on)
+		 */
+		if (!tick_oneshot_mode_active() ||
+		    (src->flags & CLOCK_SOURCE_VALID_FOR_HRES))
+			count += snprintf(buf + count,
+				  max((ssize_t)PAGE_SIZE - count, (ssize_t)0),
+				  "%s ", src->name);
+	}
+	mutex_unlock(&clocksource_mutex);
+
+	count += snprintf(buf + count,
+			  max((ssize_t)PAGE_SIZE - count, (ssize_t)0), "\n");
+
+	return count;
+}
+static DEVICE_ATTR_RO(available_clocksource);
+
+static struct attribute *clocksource_attrs[] = {
+	&dev_attr_current_clocksource.attr,
+	&dev_attr_unbind_clocksource.attr,
+	&dev_attr_available_clocksource.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(clocksource);
+
+static struct bus_type clocksource_subsys = {
+	.name = "clocksource",
+	.dev_name = "clocksource",
+};
+
+static struct device device_clocksource = {
+	.id	= 0,
+	.bus	= &clocksource_subsys,
+	.groups	= clocksource_groups,
+};
+
+static int __init init_clocksource_sysfs(void)
+{
+	int error = subsys_system_register(&clocksource_subsys, NULL);
+
+	if (!error)
+		error = device_register(&device_clocksource);
+
+	return error;
+}
+
+device_initcall(init_clocksource_sysfs);
+#endif /* CONFIG_SYSFS */
+
+/**
+ * boot_override_clocksource - boot clock override
+ * @str:	override name
+ *
+ * Takes a clocksource= boot argument and uses it
+ * as the clocksource override name.
+ */
+static int __init boot_override_clocksource(char* str)
+{
+	mutex_lock(&clocksource_mutex);
+	if (str)
+		strlcpy(override_name, str, sizeof(override_name));
+	mutex_unlock(&clocksource_mutex);
+	return 1;
+}
+
+__setup("clocksource=", boot_override_clocksource);
+
+/**
+ * boot_override_clock - Compatibility layer for deprecated boot option
+ * @str:	override name
+ *
+ * DEPRECATED! Takes a clock= boot argument and uses it
+ * as the clocksource override name
+ */
+static int __init boot_override_clock(char* str)
+{
+	if (!strcmp(str, "pmtmr")) {
+		pr_warn("clock=pmtmr is deprecated - use clocksource=acpi_pm\n");
+		return boot_override_clocksource("acpi_pm");
+	}
+	pr_warn("clock= boot option is deprecated - use clocksource=xyz\n");
+	return boot_override_clocksource(str);
+}
+
+__setup("clock=", boot_override_clock);
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
new file mode 100644
index 000000000..5561dabc9
--- /dev/null
+++ b/kernel/time/hrtimer.c
@@ -0,0 +1,2380 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
+ *  Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
+ *  Copyright(C) 2006-2007  Timesys Corp., Thomas Gleixner
+ *
+ *  High-resolution kernel timers
+ *
+ *  In contrast to the low-resolution timeout API, aka timer wheel,
+ *  hrtimers provide finer resolution and accuracy depending on system
+ *  configuration and capabilities.
+ *
+ *  Started by: Thomas Gleixner and Ingo Molnar
+ *
+ *  Credits:
+ *	Based on the original timer wheel code
+ *
+ *	Help, testing, suggestions, bugfixes, improvements were
+ *	provided by:
+ *
+ *	George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
+ *	et. al.
+ */
+
+#include <linux/cpu.h>
+#include <linux/export.h>
+#include <linux/percpu.h>
+#include <linux/hrtimer.h>
+#include <linux/notifier.h>
+#include <linux/syscalls.h>
+#include <linux/interrupt.h>
+#include <linux/tick.h>
+#include <linux/err.h>
+#include <linux/debugobjects.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/sysctl.h>
+#include <linux/sched/rt.h>
+#include <linux/sched/deadline.h>
+#include <linux/sched/nohz.h>
+#include <linux/sched/debug.h>
+#include <linux/timer.h>
+#include <linux/freezer.h>
+#include <linux/compat.h>
+
+#include <linux/uaccess.h>
+
+#include <trace/events/timer.h>
+
+#include "tick-internal.h"
+
+/*
+ * Masks for selecting the soft and hard context timers from
+ * cpu_base->active
+ */
+#define MASK_SHIFT		(HRTIMER_BASE_MONOTONIC_SOFT)
+#define HRTIMER_ACTIVE_HARD	((1U << MASK_SHIFT) - 1)
+#define HRTIMER_ACTIVE_SOFT	(HRTIMER_ACTIVE_HARD << MASK_SHIFT)
+#define HRTIMER_ACTIVE_ALL	(HRTIMER_ACTIVE_SOFT | HRTIMER_ACTIVE_HARD)
+
+/*
+ * The timer bases:
+ *
+ * There are more clockids than hrtimer bases. Thus, we index
+ * into the timer bases by the hrtimer_base_type enum. When trying
+ * to reach a base using a clockid, hrtimer_clockid_to_base()
+ * is used to convert from clockid to the proper hrtimer_base_type.
+ */
+DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
+{
+	.lock = __RAW_SPIN_LOCK_UNLOCKED(hrtimer_bases.lock),
+	.clock_base =
+	{
+		{
+			.index = HRTIMER_BASE_MONOTONIC,
+			.clockid = CLOCK_MONOTONIC,
+			.get_time = &ktime_get,
+		},
+		{
+			.index = HRTIMER_BASE_REALTIME,
+			.clockid = CLOCK_REALTIME,
+			.get_time = &ktime_get_real,
+		},
+		{
+			.index = HRTIMER_BASE_BOOTTIME,
+			.clockid = CLOCK_BOOTTIME,
+			.get_time = &ktime_get_boottime,
+		},
+		{
+			.index = HRTIMER_BASE_TAI,
+			.clockid = CLOCK_TAI,
+			.get_time = &ktime_get_clocktai,
+		},
+		{
+			.index = HRTIMER_BASE_MONOTONIC_SOFT,
+			.clockid = CLOCK_MONOTONIC,
+			.get_time = &ktime_get,
+		},
+		{
+			.index = HRTIMER_BASE_REALTIME_SOFT,
+			.clockid = CLOCK_REALTIME,
+			.get_time = &ktime_get_real,
+		},
+		{
+			.index = HRTIMER_BASE_BOOTTIME_SOFT,
+			.clockid = CLOCK_BOOTTIME,
+			.get_time = &ktime_get_boottime,
+		},
+		{
+			.index = HRTIMER_BASE_TAI_SOFT,
+			.clockid = CLOCK_TAI,
+			.get_time = &ktime_get_clocktai,
+		},
+	}
+};
+
+static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
+	/* Make sure we catch unsupported clockids */
+	[0 ... MAX_CLOCKS - 1]	= HRTIMER_MAX_CLOCK_BASES,
+
+	[CLOCK_REALTIME]	= HRTIMER_BASE_REALTIME,
+	[CLOCK_MONOTONIC]	= HRTIMER_BASE_MONOTONIC,
+	[CLOCK_BOOTTIME]	= HRTIMER_BASE_BOOTTIME,
+	[CLOCK_TAI]		= HRTIMER_BASE_TAI,
+};
+
+/*
+ * Functions and macros which are different for UP/SMP systems are kept in a
+ * single place
+ */
+#ifdef CONFIG_SMP
+
+/*
+ * We require the migration_base for lock_hrtimer_base()/switch_hrtimer_base()
+ * such that hrtimer_callback_running() can unconditionally dereference
+ * timer->base->cpu_base
+ */
+static struct hrtimer_cpu_base migration_cpu_base = {
+	.clock_base = { {
+		.cpu_base = &migration_cpu_base,
+		.seq      = SEQCNT_RAW_SPINLOCK_ZERO(migration_cpu_base.seq,
+						     &migration_cpu_base.lock),
+	}, },
+};
+
+#define migration_base	migration_cpu_base.clock_base[0]
+
+static inline bool is_migration_base(struct hrtimer_clock_base *base)
+{
+	return base == &migration_base;
+}
+
+/*
+ * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
+ * means that all timers which are tied to this base via timer->base are
+ * locked, and the base itself is locked too.
+ *
+ * So __run_timers/migrate_timers can safely modify all timers which could
+ * be found on the lists/queues.
+ *
+ * When the timer's base is locked, and the timer removed from list, it is
+ * possible to set timer->base = &migration_base and drop the lock: the timer
+ * remains locked.
+ */
+static
+struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
+					     unsigned long *flags)
+{
+	struct hrtimer_clock_base *base;
+
+	for (;;) {
+		base = READ_ONCE(timer->base);
+		if (likely(base != &migration_base)) {
+			raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
+			if (likely(base == timer->base))
+				return base;
+			/* The timer has migrated to another CPU: */
+			raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
+		}
+		cpu_relax();
+	}
+}
+
+/*
+ * We do not migrate the timer when it is expiring before the next
+ * event on the target cpu. When high resolution is enabled, we cannot
+ * reprogram the target cpu hardware and we would cause it to fire
+ * late. To keep it simple, we handle the high resolution enabled and
+ * disabled case similar.
+ *
+ * Called with cpu_base->lock of target cpu held.
+ */
+static int
+hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
+{
+	ktime_t expires;
+
+	expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
+	return expires < new_base->cpu_base->expires_next;
+}
+
+static inline
+struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base,
+					 int pinned)
+{
+#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
+	if (static_branch_likely(&timers_migration_enabled) && !pinned)
+		return &per_cpu(hrtimer_bases, get_nohz_timer_target());
+#endif
+	return base;
+}
+
+/*
+ * We switch the timer base to a power-optimized selected CPU target,
+ * if:
+ *	- NO_HZ_COMMON is enabled
+ *	- timer migration is enabled
+ *	- the timer callback is not running
+ *	- the timer is not the first expiring timer on the new target
+ *
+ * If one of the above requirements is not fulfilled we move the timer
+ * to the current CPU or leave it on the previously assigned CPU if
+ * the timer callback is currently running.
+ */
+static inline struct hrtimer_clock_base *
+switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
+		    int pinned)
+{
+	struct hrtimer_cpu_base *new_cpu_base, *this_cpu_base;
+	struct hrtimer_clock_base *new_base;
+	int basenum = base->index;
+
+	this_cpu_base = this_cpu_ptr(&hrtimer_bases);
+	new_cpu_base = get_target_base(this_cpu_base, pinned);
+again:
+	new_base = &new_cpu_base->clock_base[basenum];
+
+	if (base != new_base) {
+		/*
+		 * We are trying to move timer to new_base.
+		 * However we can't change timer's base while it is running,
+		 * so we keep it on the same CPU. No hassle vs. reprogramming
+		 * the event source in the high resolution case. The softirq
+		 * code will take care of this when the timer function has
+		 * completed. There is no conflict as we hold the lock until
+		 * the timer is enqueued.
+		 */
+		if (unlikely(hrtimer_callback_running(timer)))
+			return base;
+
+		/* See the comment in lock_hrtimer_base() */
+		WRITE_ONCE(timer->base, &migration_base);
+		raw_spin_unlock(&base->cpu_base->lock);
+		raw_spin_lock(&new_base->cpu_base->lock);
+
+		if (new_cpu_base != this_cpu_base &&
+		    hrtimer_check_target(timer, new_base)) {
+			raw_spin_unlock(&new_base->cpu_base->lock);
+			raw_spin_lock(&base->cpu_base->lock);
+			new_cpu_base = this_cpu_base;
+			WRITE_ONCE(timer->base, base);
+			goto again;
+		}
+		WRITE_ONCE(timer->base, new_base);
+	} else {
+		if (new_cpu_base != this_cpu_base &&
+		    hrtimer_check_target(timer, new_base)) {
+			new_cpu_base = this_cpu_base;
+			goto again;
+		}
+	}
+	return new_base;
+}
+
+#else /* CONFIG_SMP */
+
+static inline bool is_migration_base(struct hrtimer_clock_base *base)
+{
+	return false;
+}
+
+static inline struct hrtimer_clock_base *
+lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
+{
+	struct hrtimer_clock_base *base = timer->base;
+
+	raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
+
+	return base;
+}
+
+# define switch_hrtimer_base(t, b, p)	(b)
+
+#endif	/* !CONFIG_SMP */
+
+/*
+ * Functions for the union type storage format of ktime_t which are
+ * too large for inlining:
+ */
+#if BITS_PER_LONG < 64
+/*
+ * Divide a ktime value by a nanosecond value
+ */
+s64 __ktime_divns(const ktime_t kt, s64 div)
+{
+	int sft = 0;
+	s64 dclc;
+	u64 tmp;
+
+	dclc = ktime_to_ns(kt);
+	tmp = dclc < 0 ? -dclc : dclc;
+
+	/* Make sure the divisor is less than 2^32: */
+	while (div >> 32) {
+		sft++;
+		div >>= 1;
+	}
+	tmp >>= sft;
+	do_div(tmp, (u32) div);
+	return dclc < 0 ? -tmp : tmp;
+}
+EXPORT_SYMBOL_GPL(__ktime_divns);
+#endif /* BITS_PER_LONG >= 64 */
+
+/*
+ * Add two ktime values and do a safety check for overflow:
+ */
+ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
+{
+	ktime_t res = ktime_add_unsafe(lhs, rhs);
+
+	/*
+	 * We use KTIME_SEC_MAX here, the maximum timeout which we can
+	 * return to user space in a timespec:
+	 */
+	if (res < 0 || res < lhs || res < rhs)
+		res = ktime_set(KTIME_SEC_MAX, 0);
+
+	return res;
+}
+
+EXPORT_SYMBOL_GPL(ktime_add_safe);
+
+#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
+
+static const struct debug_obj_descr hrtimer_debug_descr;
+
+static void *hrtimer_debug_hint(void *addr)
+{
+	return ((struct hrtimer *) addr)->function;
+}
+
+/*
+ * fixup_init is called when:
+ * - an active object is initialized
+ */
+static bool hrtimer_fixup_init(void *addr, enum debug_obj_state state)
+{
+	struct hrtimer *timer = addr;
+
+	switch (state) {
+	case ODEBUG_STATE_ACTIVE:
+		hrtimer_cancel(timer);
+		debug_object_init(timer, &hrtimer_debug_descr);
+		return true;
+	default:
+		return false;
+	}
+}
+
+/*
+ * fixup_activate is called when:
+ * - an active object is activated
+ * - an unknown non-static object is activated
+ */
+static bool hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
+{
+	switch (state) {
+	case ODEBUG_STATE_ACTIVE:
+		WARN_ON(1);
+		fallthrough;
+	default:
+		return false;
+	}
+}
+
+/*
+ * fixup_free is called when:
+ * - an active object is freed
+ */
+static bool hrtimer_fixup_free(void *addr, enum debug_obj_state state)
+{
+	struct hrtimer *timer = addr;
+
+	switch (state) {
+	case ODEBUG_STATE_ACTIVE:
+		hrtimer_cancel(timer);
+		debug_object_free(timer, &hrtimer_debug_descr);
+		return true;
+	default:
+		return false;
+	}
+}
+
+static const struct debug_obj_descr hrtimer_debug_descr = {
+	.name		= "hrtimer",
+	.debug_hint	= hrtimer_debug_hint,
+	.fixup_init	= hrtimer_fixup_init,
+	.fixup_activate	= hrtimer_fixup_activate,
+	.fixup_free	= hrtimer_fixup_free,
+};
+
+static inline void debug_hrtimer_init(struct hrtimer *timer)
+{
+	debug_object_init(timer, &hrtimer_debug_descr);
+}
+
+static inline void debug_hrtimer_activate(struct hrtimer *timer,
+					  enum hrtimer_mode mode)
+{
+	debug_object_activate(timer, &hrtimer_debug_descr);
+}
+
+static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
+{
+	debug_object_deactivate(timer, &hrtimer_debug_descr);
+}
+
+static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
+			   enum hrtimer_mode mode);
+
+void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
+			   enum hrtimer_mode mode)
+{
+	debug_object_init_on_stack(timer, &hrtimer_debug_descr);
+	__hrtimer_init(timer, clock_id, mode);
+}
+EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
+
+static void __hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
+				   clockid_t clock_id, enum hrtimer_mode mode);
+
+void hrtimer_init_sleeper_on_stack(struct hrtimer_sleeper *sl,
+				   clockid_t clock_id, enum hrtimer_mode mode)
+{
+	debug_object_init_on_stack(&sl->timer, &hrtimer_debug_descr);
+	__hrtimer_init_sleeper(sl, clock_id, mode);
+}
+EXPORT_SYMBOL_GPL(hrtimer_init_sleeper_on_stack);
+
+void destroy_hrtimer_on_stack(struct hrtimer *timer)
+{
+	debug_object_free(timer, &hrtimer_debug_descr);
+}
+EXPORT_SYMBOL_GPL(destroy_hrtimer_on_stack);
+
+#else
+
+static inline void debug_hrtimer_init(struct hrtimer *timer) { }
+static inline void debug_hrtimer_activate(struct hrtimer *timer,
+					  enum hrtimer_mode mode) { }
+static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
+#endif
+
+static inline void
+debug_init(struct hrtimer *timer, clockid_t clockid,
+	   enum hrtimer_mode mode)
+{
+	debug_hrtimer_init(timer);
+	trace_hrtimer_init(timer, clockid, mode);
+}
+
+static inline void debug_activate(struct hrtimer *timer,
+				  enum hrtimer_mode mode)
+{
+	debug_hrtimer_activate(timer, mode);
+	trace_hrtimer_start(timer, mode);
+}
+
+static inline void debug_deactivate(struct hrtimer *timer)
+{
+	debug_hrtimer_deactivate(timer);
+	trace_hrtimer_cancel(timer);
+}
+
+static struct hrtimer_clock_base *
+__next_base(struct hrtimer_cpu_base *cpu_base, unsigned int *active)
+{
+	unsigned int idx;
+
+	if (!*active)
+		return NULL;
+
+	idx = __ffs(*active);
+	*active &= ~(1U << idx);
+
+	return &cpu_base->clock_base[idx];
+}
+
+#define for_each_active_base(base, cpu_base, active)	\
+	while ((base = __next_base((cpu_base), &(active))))
+
+static ktime_t __hrtimer_next_event_base(struct hrtimer_cpu_base *cpu_base,
+					 const struct hrtimer *exclude,
+					 unsigned int active,
+					 ktime_t expires_next)
+{
+	struct hrtimer_clock_base *base;
+	ktime_t expires;
+
+	for_each_active_base(base, cpu_base, active) {
+		struct timerqueue_node *next;
+		struct hrtimer *timer;
+
+		next = timerqueue_getnext(&base->active);
+		timer = container_of(next, struct hrtimer, node);
+		if (timer == exclude) {
+			/* Get to the next timer in the queue. */
+			next = timerqueue_iterate_next(next);
+			if (!next)
+				continue;
+
+			timer = container_of(next, struct hrtimer, node);
+		}
+		expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
+		if (expires < expires_next) {
+			expires_next = expires;
+
+			/* Skip cpu_base update if a timer is being excluded. */
+			if (exclude)
+				continue;
+
+			if (timer->is_soft)
+				cpu_base->softirq_next_timer = timer;
+			else
+				cpu_base->next_timer = timer;
+		}
+	}
+	/*
+	 * clock_was_set() might have changed base->offset of any of
+	 * the clock bases so the result might be negative. Fix it up
+	 * to prevent a false positive in clockevents_program_event().
+	 */
+	if (expires_next < 0)
+		expires_next = 0;
+	return expires_next;
+}
+
+/*
+ * Recomputes cpu_base::*next_timer and returns the earliest expires_next
+ * but does not set cpu_base::*expires_next, that is done by
+ * hrtimer[_force]_reprogram and hrtimer_interrupt only. When updating
+ * cpu_base::*expires_next right away, reprogramming logic would no longer
+ * work.
+ *
+ * When a softirq is pending, we can ignore the HRTIMER_ACTIVE_SOFT bases,
+ * those timers will get run whenever the softirq gets handled, at the end of
+ * hrtimer_run_softirq(), hrtimer_update_softirq_timer() will re-add these bases.
+ *
+ * Therefore softirq values are those from the HRTIMER_ACTIVE_SOFT clock bases.
+ * The !softirq values are the minima across HRTIMER_ACTIVE_ALL, unless an actual
+ * softirq is pending, in which case they're the minima of HRTIMER_ACTIVE_HARD.
+ *
+ * @active_mask must be one of:
+ *  - HRTIMER_ACTIVE_ALL,
+ *  - HRTIMER_ACTIVE_SOFT, or
+ *  - HRTIMER_ACTIVE_HARD.
+ */
+static ktime_t
+__hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base, unsigned int active_mask)
+{
+	unsigned int active;
+	struct hrtimer *next_timer = NULL;
+	ktime_t expires_next = KTIME_MAX;
+
+	if (!cpu_base->softirq_activated && (active_mask & HRTIMER_ACTIVE_SOFT)) {
+		active = cpu_base->active_bases & HRTIMER_ACTIVE_SOFT;
+		cpu_base->softirq_next_timer = NULL;
+		expires_next = __hrtimer_next_event_base(cpu_base, NULL,
+							 active, KTIME_MAX);
+
+		next_timer = cpu_base->softirq_next_timer;
+	}
+
+	if (active_mask & HRTIMER_ACTIVE_HARD) {
+		active = cpu_base->active_bases & HRTIMER_ACTIVE_HARD;
+		cpu_base->next_timer = next_timer;
+		expires_next = __hrtimer_next_event_base(cpu_base, NULL, active,
+							 expires_next);
+	}
+
+	return expires_next;
+}
+
+static ktime_t hrtimer_update_next_event(struct hrtimer_cpu_base *cpu_base)
+{
+	ktime_t expires_next, soft = KTIME_MAX;
+
+	/*
+	 * If the soft interrupt has already been activated, ignore the
+	 * soft bases. They will be handled in the already raised soft
+	 * interrupt.
+	 */
+	if (!cpu_base->softirq_activated) {
+		soft = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_SOFT);
+		/*
+		 * Update the soft expiry time. clock_settime() might have
+		 * affected it.
+		 */
+		cpu_base->softirq_expires_next = soft;
+	}
+
+	expires_next = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_HARD);
+	/*
+	 * If a softirq timer is expiring first, update cpu_base->next_timer
+	 * and program the hardware with the soft expiry time.
+	 */
+	if (expires_next > soft) {
+		cpu_base->next_timer = cpu_base->softirq_next_timer;
+		expires_next = soft;
+	}
+
+	return expires_next;
+}
+
+static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
+{
+	ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;
+	ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset;
+	ktime_t *offs_tai = &base->clock_base[HRTIMER_BASE_TAI].offset;
+
+	ktime_t now = ktime_get_update_offsets_now(&base->clock_was_set_seq,
+					    offs_real, offs_boot, offs_tai);
+
+	base->clock_base[HRTIMER_BASE_REALTIME_SOFT].offset = *offs_real;
+	base->clock_base[HRTIMER_BASE_BOOTTIME_SOFT].offset = *offs_boot;
+	base->clock_base[HRTIMER_BASE_TAI_SOFT].offset = *offs_tai;
+
+	return now;
+}
+
+/*
+ * Is the high resolution mode active ?
+ */
+static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *cpu_base)
+{
+	return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ?
+		cpu_base->hres_active : 0;
+}
+
+static inline int hrtimer_hres_active(void)
+{
+	return __hrtimer_hres_active(this_cpu_ptr(&hrtimer_bases));
+}
+
+static void __hrtimer_reprogram(struct hrtimer_cpu_base *cpu_base,
+				struct hrtimer *next_timer,
+				ktime_t expires_next)
+{
+	cpu_base->expires_next = expires_next;
+
+	/*
+	 * If hres is not active, hardware does not have to be
+	 * reprogrammed yet.
+	 *
+	 * If a hang was detected in the last timer interrupt then we
+	 * leave the hang delay active in the hardware. We want the
+	 * system to make progress. That also prevents the following
+	 * scenario:
+	 * T1 expires 50ms from now
+	 * T2 expires 5s from now
+	 *
+	 * T1 is removed, so this code is called and would reprogram
+	 * the hardware to 5s from now. Any hrtimer_start after that
+	 * will not reprogram the hardware due to hang_detected being
+	 * set. So we'd effectively block all timers until the T2 event
+	 * fires.
+	 */
+	if (!__hrtimer_hres_active(cpu_base) || cpu_base->hang_detected)
+		return;
+
+	tick_program_event(expires_next, 1);
+}
+
+/*
+ * Reprogram the event source with checking both queues for the
+ * next event
+ * Called with interrupts disabled and base->lock held
+ */
+static void
+hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
+{
+	ktime_t expires_next;
+
+	expires_next = hrtimer_update_next_event(cpu_base);
+
+	if (skip_equal && expires_next == cpu_base->expires_next)
+		return;
+
+	__hrtimer_reprogram(cpu_base, cpu_base->next_timer, expires_next);
+}
+
+/* High resolution timer related functions */
+#ifdef CONFIG_HIGH_RES_TIMERS
+
+/*
+ * High resolution timer enabled ?
+ */
+static bool hrtimer_hres_enabled __read_mostly  = true;
+unsigned int hrtimer_resolution __read_mostly = LOW_RES_NSEC;
+EXPORT_SYMBOL_GPL(hrtimer_resolution);
+
+/*
+ * Enable / Disable high resolution mode
+ */
+static int __init setup_hrtimer_hres(char *str)
+{
+	return (kstrtobool(str, &hrtimer_hres_enabled) == 0);
+}
+
+__setup("highres=", setup_hrtimer_hres);
+
+/*
+ * hrtimer_high_res_enabled - query, if the highres mode is enabled
+ */
+static inline int hrtimer_is_hres_enabled(void)
+{
+	return hrtimer_hres_enabled;
+}
+
+static void retrigger_next_event(void *arg);
+
+/*
+ * Switch to high resolution mode
+ */
+static void hrtimer_switch_to_hres(void)
+{
+	struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
+
+	if (tick_init_highres()) {
+		pr_warn("Could not switch to high resolution mode on CPU %u\n",
+			base->cpu);
+		return;
+	}
+	base->hres_active = 1;
+	hrtimer_resolution = HIGH_RES_NSEC;
+
+	tick_setup_sched_timer();
+	/* "Retrigger" the interrupt to get things going */
+	retrigger_next_event(NULL);
+}
+
+#else
+
+static inline int hrtimer_is_hres_enabled(void) { return 0; }
+static inline void hrtimer_switch_to_hres(void) { }
+
+#endif /* CONFIG_HIGH_RES_TIMERS */
+/*
+ * Retrigger next event is called after clock was set with interrupts
+ * disabled through an SMP function call or directly from low level
+ * resume code.
+ *
+ * This is only invoked when:
+ *	- CONFIG_HIGH_RES_TIMERS is enabled.
+ *	- CONFIG_NOHZ_COMMON is enabled
+ *
+ * For the other cases this function is empty and because the call sites
+ * are optimized out it vanishes as well, i.e. no need for lots of
+ * #ifdeffery.
+ */
+static void retrigger_next_event(void *arg)
+{
+	struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
+
+	/*
+	 * When high resolution mode or nohz is active, then the offsets of
+	 * CLOCK_REALTIME/TAI/BOOTTIME have to be updated. Otherwise the
+	 * next tick will take care of that.
+	 *
+	 * If high resolution mode is active then the next expiring timer
+	 * must be reevaluated and the clock event device reprogrammed if
+	 * necessary.
+	 *
+	 * In the NOHZ case the update of the offset and the reevaluation
+	 * of the next expiring timer is enough. The return from the SMP
+	 * function call will take care of the reprogramming in case the
+	 * CPU was in a NOHZ idle sleep.
+	 */
+	if (!__hrtimer_hres_active(base) && !tick_nohz_active)
+		return;
+
+	raw_spin_lock(&base->lock);
+	hrtimer_update_base(base);
+	if (__hrtimer_hres_active(base))
+		hrtimer_force_reprogram(base, 0);
+	else
+		hrtimer_update_next_event(base);
+	raw_spin_unlock(&base->lock);
+}
+
+/*
+ * When a timer is enqueued and expires earlier than the already enqueued
+ * timers, we have to check, whether it expires earlier than the timer for
+ * which the clock event device was armed.
+ *
+ * Called with interrupts disabled and base->cpu_base.lock held
+ */
+static void hrtimer_reprogram(struct hrtimer *timer, bool reprogram)
+{
+	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
+	struct hrtimer_clock_base *base = timer->base;
+	ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
+
+	WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
+
+	/*
+	 * CLOCK_REALTIME timer might be requested with an absolute
+	 * expiry time which is less than base->offset. Set it to 0.
+	 */
+	if (expires < 0)
+		expires = 0;
+
+	if (timer->is_soft) {
+		/*
+		 * soft hrtimer could be started on a remote CPU. In this
+		 * case softirq_expires_next needs to be updated on the
+		 * remote CPU. The soft hrtimer will not expire before the
+		 * first hard hrtimer on the remote CPU -
+		 * hrtimer_check_target() prevents this case.
+		 */
+		struct hrtimer_cpu_base *timer_cpu_base = base->cpu_base;
+
+		if (timer_cpu_base->softirq_activated)
+			return;
+
+		if (!ktime_before(expires, timer_cpu_base->softirq_expires_next))
+			return;
+
+		timer_cpu_base->softirq_next_timer = timer;
+		timer_cpu_base->softirq_expires_next = expires;
+
+		if (!ktime_before(expires, timer_cpu_base->expires_next) ||
+		    !reprogram)
+			return;
+	}
+
+	/*
+	 * If the timer is not on the current cpu, we cannot reprogram
+	 * the other cpus clock event device.
+	 */
+	if (base->cpu_base != cpu_base)
+		return;
+
+	if (expires >= cpu_base->expires_next)
+		return;
+
+	/*
+	 * If the hrtimer interrupt is running, then it will reevaluate the
+	 * clock bases and reprogram the clock event device.
+	 */
+	if (cpu_base->in_hrtirq)
+		return;
+
+	cpu_base->next_timer = timer;
+
+	__hrtimer_reprogram(cpu_base, timer, expires);
+}
+
+static bool update_needs_ipi(struct hrtimer_cpu_base *cpu_base,
+			     unsigned int active)
+{
+	struct hrtimer_clock_base *base;
+	unsigned int seq;
+	ktime_t expires;
+
+	/*
+	 * Update the base offsets unconditionally so the following
+	 * checks whether the SMP function call is required works.
+	 *
+	 * The update is safe even when the remote CPU is in the hrtimer
+	 * interrupt or the hrtimer soft interrupt and expiring affected
+	 * bases. Either it will see the update before handling a base or
+	 * it will see it when it finishes the processing and reevaluates
+	 * the next expiring timer.
+	 */
+	seq = cpu_base->clock_was_set_seq;
+	hrtimer_update_base(cpu_base);
+
+	/*
+	 * If the sequence did not change over the update then the
+	 * remote CPU already handled it.
+	 */
+	if (seq == cpu_base->clock_was_set_seq)
+		return false;
+
+	/*
+	 * If the remote CPU is currently handling an hrtimer interrupt, it
+	 * will reevaluate the first expiring timer of all clock bases
+	 * before reprogramming. Nothing to do here.
+	 */
+	if (cpu_base->in_hrtirq)
+		return false;
+
+	/*
+	 * Walk the affected clock bases and check whether the first expiring
+	 * timer in a clock base is moving ahead of the first expiring timer of
+	 * @cpu_base. If so, the IPI must be invoked because per CPU clock
+	 * event devices cannot be remotely reprogrammed.
+	 */
+	active &= cpu_base->active_bases;
+
+	for_each_active_base(base, cpu_base, active) {
+		struct timerqueue_node *next;
+
+		next = timerqueue_getnext(&base->active);
+		expires = ktime_sub(next->expires, base->offset);
+		if (expires < cpu_base->expires_next)
+			return true;
+
+		/* Extra check for softirq clock bases */
+		if (base->clockid < HRTIMER_BASE_MONOTONIC_SOFT)
+			continue;
+		if (cpu_base->softirq_activated)
+			continue;
+		if (expires < cpu_base->softirq_expires_next)
+			return true;
+	}
+	return false;
+}
+
+/*
+ * Clock was set. This might affect CLOCK_REALTIME, CLOCK_TAI and
+ * CLOCK_BOOTTIME (for late sleep time injection).
+ *
+ * This requires to update the offsets for these clocks
+ * vs. CLOCK_MONOTONIC. When high resolution timers are enabled, then this
+ * also requires to eventually reprogram the per CPU clock event devices
+ * when the change moves an affected timer ahead of the first expiring
+ * timer on that CPU. Obviously remote per CPU clock event devices cannot
+ * be reprogrammed. The other reason why an IPI has to be sent is when the
+ * system is in !HIGH_RES and NOHZ mode. The NOHZ mode updates the offsets
+ * in the tick, which obviously might be stopped, so this has to bring out
+ * the remote CPU which might sleep in idle to get this sorted.
+ */
+void clock_was_set(unsigned int bases)
+{
+	struct hrtimer_cpu_base *cpu_base = raw_cpu_ptr(&hrtimer_bases);
+	cpumask_var_t mask;
+	int cpu;
+
+	if (!__hrtimer_hres_active(cpu_base) && !tick_nohz_active)
+		goto out_timerfd;
+
+	if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) {
+		on_each_cpu(retrigger_next_event, NULL, 1);
+		goto out_timerfd;
+	}
+
+	/* Avoid interrupting CPUs if possible */
+	cpus_read_lock();
+	for_each_online_cpu(cpu) {
+		unsigned long flags;
+
+		cpu_base = &per_cpu(hrtimer_bases, cpu);
+		raw_spin_lock_irqsave(&cpu_base->lock, flags);
+
+		if (update_needs_ipi(cpu_base, bases))
+			cpumask_set_cpu(cpu, mask);
+
+		raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
+	}
+
+	preempt_disable();
+	smp_call_function_many(mask, retrigger_next_event, NULL, 1);
+	preempt_enable();
+	cpus_read_unlock();
+	free_cpumask_var(mask);
+
+out_timerfd:
+	timerfd_clock_was_set();
+}
+
+static void clock_was_set_work(struct work_struct *work)
+{
+	clock_was_set(CLOCK_SET_WALL);
+}
+
+static DECLARE_WORK(hrtimer_work, clock_was_set_work);
+
+/*
+ * Called from timekeeping code to reprogram the hrtimer interrupt device
+ * on all cpus and to notify timerfd.
+ */
+void clock_was_set_delayed(void)
+{
+	schedule_work(&hrtimer_work);
+}
+
+/*
+ * Called during resume either directly from via timekeeping_resume()
+ * or in the case of s2idle from tick_unfreeze() to ensure that the
+ * hrtimers are up to date.
+ */
+void hrtimers_resume_local(void)
+{
+	lockdep_assert_irqs_disabled();
+	/* Retrigger on the local CPU */
+	retrigger_next_event(NULL);
+}
+
+/*
+ * Counterpart to lock_hrtimer_base above:
+ */
+static inline
+void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
+{
+	raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
+}
+
+/**
+ * hrtimer_forward - forward the timer expiry
+ * @timer:	hrtimer to forward
+ * @now:	forward past this time
+ * @interval:	the interval to forward
+ *
+ * Forward the timer expiry so it will expire in the future.
+ * Returns the number of overruns.
+ *
+ * Can be safely called from the callback function of @timer. If
+ * called from other contexts @timer must neither be enqueued nor
+ * running the callback and the caller needs to take care of
+ * serialization.
+ *
+ * Note: This only updates the timer expiry value and does not requeue
+ * the timer.
+ */
+u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
+{
+	u64 orun = 1;
+	ktime_t delta;
+
+	delta = ktime_sub(now, hrtimer_get_expires(timer));
+
+	if (delta < 0)
+		return 0;
+
+	if (WARN_ON(timer->state & HRTIMER_STATE_ENQUEUED))
+		return 0;
+
+	if (interval < hrtimer_resolution)
+		interval = hrtimer_resolution;
+
+	if (unlikely(delta >= interval)) {
+		s64 incr = ktime_to_ns(interval);
+
+		orun = ktime_divns(delta, incr);
+		hrtimer_add_expires_ns(timer, incr * orun);
+		if (hrtimer_get_expires_tv64(timer) > now)
+			return orun;
+		/*
+		 * This (and the ktime_add() below) is the
+		 * correction for exact:
+		 */
+		orun++;
+	}
+	hrtimer_add_expires(timer, interval);
+
+	return orun;
+}
+EXPORT_SYMBOL_GPL(hrtimer_forward);
+
+/*
+ * enqueue_hrtimer - internal function to (re)start a timer
+ *
+ * The timer is inserted in expiry order. Insertion into the
+ * red black tree is O(log(n)). Must hold the base lock.
+ *
+ * Returns 1 when the new timer is the leftmost timer in the tree.
+ */
+static int enqueue_hrtimer(struct hrtimer *timer,
+			   struct hrtimer_clock_base *base,
+			   enum hrtimer_mode mode)
+{
+	debug_activate(timer, mode);
+
+	base->cpu_base->active_bases |= 1 << base->index;
+
+	/* Pairs with the lockless read in hrtimer_is_queued() */
+	WRITE_ONCE(timer->state, HRTIMER_STATE_ENQUEUED);
+
+	return timerqueue_add(&base->active, &timer->node);
+}
+
+/*
+ * __remove_hrtimer - internal function to remove a timer
+ *
+ * Caller must hold the base lock.
+ *
+ * High resolution timer mode reprograms the clock event device when the
+ * timer is the one which expires next. The caller can disable this by setting
+ * reprogram to zero. This is useful, when the context does a reprogramming
+ * anyway (e.g. timer interrupt)
+ */
+static void __remove_hrtimer(struct hrtimer *timer,
+			     struct hrtimer_clock_base *base,
+			     u8 newstate, int reprogram)
+{
+	struct hrtimer_cpu_base *cpu_base = base->cpu_base;
+	u8 state = timer->state;
+
+	/* Pairs with the lockless read in hrtimer_is_queued() */
+	WRITE_ONCE(timer->state, newstate);
+	if (!(state & HRTIMER_STATE_ENQUEUED))
+		return;
+
+	if (!timerqueue_del(&base->active, &timer->node))
+		cpu_base->active_bases &= ~(1 << base->index);
+
+	/*
+	 * Note: If reprogram is false we do not update
+	 * cpu_base->next_timer. This happens when we remove the first
+	 * timer on a remote cpu. No harm as we never dereference
+	 * cpu_base->next_timer. So the worst thing what can happen is
+	 * an superfluous call to hrtimer_force_reprogram() on the
+	 * remote cpu later on if the same timer gets enqueued again.
+	 */
+	if (reprogram && timer == cpu_base->next_timer)
+		hrtimer_force_reprogram(cpu_base, 1);
+}
+
+/*
+ * remove hrtimer, called with base lock held
+ */
+static inline int
+remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base,
+	       bool restart, bool keep_local)
+{
+	u8 state = timer->state;
+
+	if (state & HRTIMER_STATE_ENQUEUED) {
+		bool reprogram;
+
+		/*
+		 * Remove the timer and force reprogramming when high
+		 * resolution mode is active and the timer is on the current
+		 * CPU. If we remove a timer on another CPU, reprogramming is
+		 * skipped. The interrupt event on this CPU is fired and
+		 * reprogramming happens in the interrupt handler. This is a
+		 * rare case and less expensive than a smp call.
+		 */
+		debug_deactivate(timer);
+		reprogram = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
+
+		/*
+		 * If the timer is not restarted then reprogramming is
+		 * required if the timer is local. If it is local and about
+		 * to be restarted, avoid programming it twice (on removal
+		 * and a moment later when it's requeued).
+		 */
+		if (!restart)
+			state = HRTIMER_STATE_INACTIVE;
+		else
+			reprogram &= !keep_local;
+
+		__remove_hrtimer(timer, base, state, reprogram);
+		return 1;
+	}
+	return 0;
+}
+
+static inline ktime_t hrtimer_update_lowres(struct hrtimer *timer, ktime_t tim,
+					    const enum hrtimer_mode mode)
+{
+#ifdef CONFIG_TIME_LOW_RES
+	/*
+	 * CONFIG_TIME_LOW_RES indicates that the system has no way to return
+	 * granular time values. For relative timers we add hrtimer_resolution
+	 * (i.e. one jiffie) to prevent short timeouts.
+	 */
+	timer->is_rel = mode & HRTIMER_MODE_REL;
+	if (timer->is_rel)
+		tim = ktime_add_safe(tim, hrtimer_resolution);
+#endif
+	return tim;
+}
+
+static void
+hrtimer_update_softirq_timer(struct hrtimer_cpu_base *cpu_base, bool reprogram)
+{
+	ktime_t expires;
+
+	/*
+	 * Find the next SOFT expiration.
+	 */
+	expires = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_SOFT);
+
+	/*
+	 * reprogramming needs to be triggered, even if the next soft
+	 * hrtimer expires at the same time than the next hard
+	 * hrtimer. cpu_base->softirq_expires_next needs to be updated!
+	 */
+	if (expires == KTIME_MAX)
+		return;
+
+	/*
+	 * cpu_base->*next_timer is recomputed by __hrtimer_get_next_event()
+	 * cpu_base->*expires_next is only set by hrtimer_reprogram()
+	 */
+	hrtimer_reprogram(cpu_base->softirq_next_timer, reprogram);
+}
+
+static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
+				    u64 delta_ns, const enum hrtimer_mode mode,
+				    struct hrtimer_clock_base *base)
+{
+	struct hrtimer_clock_base *new_base;
+	bool force_local, first;
+
+	/*
+	 * If the timer is on the local cpu base and is the first expiring
+	 * timer then this might end up reprogramming the hardware twice
+	 * (on removal and on enqueue). To avoid that by prevent the
+	 * reprogram on removal, keep the timer local to the current CPU
+	 * and enforce reprogramming after it is queued no matter whether
+	 * it is the new first expiring timer again or not.
+	 */
+	force_local = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
+	force_local &= base->cpu_base->next_timer == timer;
+
+	/*
+	 * Remove an active timer from the queue. In case it is not queued
+	 * on the current CPU, make sure that remove_hrtimer() updates the
+	 * remote data correctly.
+	 *
+	 * If it's on the current CPU and the first expiring timer, then
+	 * skip reprogramming, keep the timer local and enforce
+	 * reprogramming later if it was the first expiring timer.  This
+	 * avoids programming the underlying clock event twice (once at
+	 * removal and once after enqueue).
+	 */
+	remove_hrtimer(timer, base, true, force_local);
+
+	if (mode & HRTIMER_MODE_REL)
+		tim = ktime_add_safe(tim, base->get_time());
+
+	tim = hrtimer_update_lowres(timer, tim, mode);
+
+	hrtimer_set_expires_range_ns(timer, tim, delta_ns);
+
+	/* Switch the timer base, if necessary: */
+	if (!force_local) {
+		new_base = switch_hrtimer_base(timer, base,
+					       mode & HRTIMER_MODE_PINNED);
+	} else {
+		new_base = base;
+	}
+
+	first = enqueue_hrtimer(timer, new_base, mode);
+	if (!force_local)
+		return first;
+
+	/*
+	 * Timer was forced to stay on the current CPU to avoid
+	 * reprogramming on removal and enqueue. Force reprogram the
+	 * hardware by evaluating the new first expiring timer.
+	 */
+	hrtimer_force_reprogram(new_base->cpu_base, 1);
+	return 0;
+}
+
+/**
+ * hrtimer_start_range_ns - (re)start an hrtimer
+ * @timer:	the timer to be added
+ * @tim:	expiry time
+ * @delta_ns:	"slack" range for the timer
+ * @mode:	timer mode: absolute (HRTIMER_MODE_ABS) or
+ *		relative (HRTIMER_MODE_REL), and pinned (HRTIMER_MODE_PINNED);
+ *		softirq based mode is considered for debug purpose only!
+ */
+void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
+			    u64 delta_ns, const enum hrtimer_mode mode)
+{
+	struct hrtimer_clock_base *base;
+	unsigned long flags;
+
+	/*
+	 * Check whether the HRTIMER_MODE_SOFT bit and hrtimer.is_soft
+	 * match on CONFIG_PREEMPT_RT = n. With PREEMPT_RT check the hard
+	 * expiry mode because unmarked timers are moved to softirq expiry.
+	 */
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		WARN_ON_ONCE(!(mode & HRTIMER_MODE_SOFT) ^ !timer->is_soft);
+	else
+		WARN_ON_ONCE(!(mode & HRTIMER_MODE_HARD) ^ !timer->is_hard);
+
+	base = lock_hrtimer_base(timer, &flags);
+
+	if (__hrtimer_start_range_ns(timer, tim, delta_ns, mode, base))
+		hrtimer_reprogram(timer, true);
+
+	unlock_hrtimer_base(timer, &flags);
+}
+EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
+
+/**
+ * hrtimer_try_to_cancel - try to deactivate a timer
+ * @timer:	hrtimer to stop
+ *
+ * Returns:
+ *
+ *  *  0 when the timer was not active
+ *  *  1 when the timer was active
+ *  * -1 when the timer is currently executing the callback function and
+ *    cannot be stopped
+ */
+int hrtimer_try_to_cancel(struct hrtimer *timer)
+{
+	struct hrtimer_clock_base *base;
+	unsigned long flags;
+	int ret = -1;
+
+	/*
+	 * Check lockless first. If the timer is not active (neither
+	 * enqueued nor running the callback, nothing to do here.  The
+	 * base lock does not serialize against a concurrent enqueue,
+	 * so we can avoid taking it.
+	 */
+	if (!hrtimer_active(timer))
+		return 0;
+
+	base = lock_hrtimer_base(timer, &flags);
+
+	if (!hrtimer_callback_running(timer))
+		ret = remove_hrtimer(timer, base, false, false);
+
+	unlock_hrtimer_base(timer, &flags);
+
+	return ret;
+
+}
+EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
+
+#ifdef CONFIG_PREEMPT_RT
+static void hrtimer_cpu_base_init_expiry_lock(struct hrtimer_cpu_base *base)
+{
+	spin_lock_init(&base->softirq_expiry_lock);
+}
+
+static void hrtimer_cpu_base_lock_expiry(struct hrtimer_cpu_base *base)
+{
+	spin_lock(&base->softirq_expiry_lock);
+}
+
+static void hrtimer_cpu_base_unlock_expiry(struct hrtimer_cpu_base *base)
+{
+	spin_unlock(&base->softirq_expiry_lock);
+}
+
+/*
+ * The counterpart to hrtimer_cancel_wait_running().
+ *
+ * If there is a waiter for cpu_base->expiry_lock, then it was waiting for
+ * the timer callback to finish. Drop expiry_lock and reacquire it. That
+ * allows the waiter to acquire the lock and make progress.
+ */
+static void hrtimer_sync_wait_running(struct hrtimer_cpu_base *cpu_base,
+				      unsigned long flags)
+{
+	if (atomic_read(&cpu_base->timer_waiters)) {
+		raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
+		spin_unlock(&cpu_base->softirq_expiry_lock);
+		spin_lock(&cpu_base->softirq_expiry_lock);
+		raw_spin_lock_irq(&cpu_base->lock);
+	}
+}
+
+/*
+ * This function is called on PREEMPT_RT kernels when the fast path
+ * deletion of a timer failed because the timer callback function was
+ * running.
+ *
+ * This prevents priority inversion: if the soft irq thread is preempted
+ * in the middle of a timer callback, then calling del_timer_sync() can
+ * lead to two issues:
+ *
+ *  - If the caller is on a remote CPU then it has to spin wait for the timer
+ *    handler to complete. This can result in unbound priority inversion.
+ *
+ *  - If the caller originates from the task which preempted the timer
+ *    handler on the same CPU, then spin waiting for the timer handler to
+ *    complete is never going to end.
+ */
+void hrtimer_cancel_wait_running(const struct hrtimer *timer)
+{
+	/* Lockless read. Prevent the compiler from reloading it below */
+	struct hrtimer_clock_base *base = READ_ONCE(timer->base);
+
+	/*
+	 * Just relax if the timer expires in hard interrupt context or if
+	 * it is currently on the migration base.
+	 */
+	if (!timer->is_soft || is_migration_base(base)) {
+		cpu_relax();
+		return;
+	}
+
+	/*
+	 * Mark the base as contended and grab the expiry lock, which is
+	 * held by the softirq across the timer callback. Drop the lock
+	 * immediately so the softirq can expire the next timer. In theory
+	 * the timer could already be running again, but that's more than
+	 * unlikely and just causes another wait loop.
+	 */
+	atomic_inc(&base->cpu_base->timer_waiters);
+	spin_lock_bh(&base->cpu_base->softirq_expiry_lock);
+	atomic_dec(&base->cpu_base->timer_waiters);
+	spin_unlock_bh(&base->cpu_base->softirq_expiry_lock);
+}
+#else
+static inline void
+hrtimer_cpu_base_init_expiry_lock(struct hrtimer_cpu_base *base) { }
+static inline void
+hrtimer_cpu_base_lock_expiry(struct hrtimer_cpu_base *base) { }
+static inline void
+hrtimer_cpu_base_unlock_expiry(struct hrtimer_cpu_base *base) { }
+static inline void hrtimer_sync_wait_running(struct hrtimer_cpu_base *base,
+					     unsigned long flags) { }
+#endif
+
+/**
+ * hrtimer_cancel - cancel a timer and wait for the handler to finish.
+ * @timer:	the timer to be cancelled
+ *
+ * Returns:
+ *  0 when the timer was not active
+ *  1 when the timer was active
+ */
+int hrtimer_cancel(struct hrtimer *timer)
+{
+	int ret;
+
+	do {
+		ret = hrtimer_try_to_cancel(timer);
+
+		if (ret < 0)
+			hrtimer_cancel_wait_running(timer);
+	} while (ret < 0);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hrtimer_cancel);
+
+/**
+ * __hrtimer_get_remaining - get remaining time for the timer
+ * @timer:	the timer to read
+ * @adjust:	adjust relative timers when CONFIG_TIME_LOW_RES=y
+ */
+ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust)
+{
+	unsigned long flags;
+	ktime_t rem;
+
+	lock_hrtimer_base(timer, &flags);
+	if (IS_ENABLED(CONFIG_TIME_LOW_RES) && adjust)
+		rem = hrtimer_expires_remaining_adjusted(timer);
+	else
+		rem = hrtimer_expires_remaining(timer);
+	unlock_hrtimer_base(timer, &flags);
+
+	return rem;
+}
+EXPORT_SYMBOL_GPL(__hrtimer_get_remaining);
+
+#ifdef CONFIG_NO_HZ_COMMON
+/**
+ * hrtimer_get_next_event - get the time until next expiry event
+ *
+ * Returns the next expiry time or KTIME_MAX if no timer is pending.
+ */
+u64 hrtimer_get_next_event(void)
+{
+	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
+	u64 expires = KTIME_MAX;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&cpu_base->lock, flags);
+
+	if (!__hrtimer_hres_active(cpu_base))
+		expires = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_ALL);
+
+	raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
+
+	return expires;
+}
+
+/**
+ * hrtimer_next_event_without - time until next expiry event w/o one timer
+ * @exclude:	timer to exclude
+ *
+ * Returns the next expiry time over all timers except for the @exclude one or
+ * KTIME_MAX if none of them is pending.
+ */
+u64 hrtimer_next_event_without(const struct hrtimer *exclude)
+{
+	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
+	u64 expires = KTIME_MAX;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&cpu_base->lock, flags);
+
+	if (__hrtimer_hres_active(cpu_base)) {
+		unsigned int active;
+
+		if (!cpu_base->softirq_activated) {
+			active = cpu_base->active_bases & HRTIMER_ACTIVE_SOFT;
+			expires = __hrtimer_next_event_base(cpu_base, exclude,
+							    active, KTIME_MAX);
+		}
+		active = cpu_base->active_bases & HRTIMER_ACTIVE_HARD;
+		expires = __hrtimer_next_event_base(cpu_base, exclude, active,
+						    expires);
+	}
+
+	raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
+
+	return expires;
+}
+#endif
+
+static inline int hrtimer_clockid_to_base(clockid_t clock_id)
+{
+	if (likely(clock_id < MAX_CLOCKS)) {
+		int base = hrtimer_clock_to_base_table[clock_id];
+
+		if (likely(base != HRTIMER_MAX_CLOCK_BASES))
+			return base;
+	}
+	WARN(1, "Invalid clockid %d. Using MONOTONIC\n", clock_id);
+	return HRTIMER_BASE_MONOTONIC;
+}
+
+static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
+			   enum hrtimer_mode mode)
+{
+	bool softtimer = !!(mode & HRTIMER_MODE_SOFT);
+	struct hrtimer_cpu_base *cpu_base;
+	int base;
+
+	/*
+	 * On PREEMPT_RT enabled kernels hrtimers which are not explicitly
+	 * marked for hard interrupt expiry mode are moved into soft
+	 * interrupt context for latency reasons and because the callbacks
+	 * can invoke functions which might sleep on RT, e.g. spin_lock().
+	 */
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && !(mode & HRTIMER_MODE_HARD))
+		softtimer = true;
+
+	memset(timer, 0, sizeof(struct hrtimer));
+
+	cpu_base = raw_cpu_ptr(&hrtimer_bases);
+
+	/*
+	 * POSIX magic: Relative CLOCK_REALTIME timers are not affected by
+	 * clock modifications, so they needs to become CLOCK_MONOTONIC to
+	 * ensure POSIX compliance.
+	 */
+	if (clock_id == CLOCK_REALTIME && mode & HRTIMER_MODE_REL)
+		clock_id = CLOCK_MONOTONIC;
+
+	base = softtimer ? HRTIMER_MAX_CLOCK_BASES / 2 : 0;
+	base += hrtimer_clockid_to_base(clock_id);
+	timer->is_soft = softtimer;
+	timer->is_hard = !!(mode & HRTIMER_MODE_HARD);
+	timer->base = &cpu_base->clock_base[base];
+	timerqueue_init(&timer->node);
+}
+
+/**
+ * hrtimer_init - initialize a timer to the given clock
+ * @timer:	the timer to be initialized
+ * @clock_id:	the clock to be used
+ * @mode:       The modes which are relevant for initialization:
+ *              HRTIMER_MODE_ABS, HRTIMER_MODE_REL, HRTIMER_MODE_ABS_SOFT,
+ *              HRTIMER_MODE_REL_SOFT
+ *
+ *              The PINNED variants of the above can be handed in,
+ *              but the PINNED bit is ignored as pinning happens
+ *              when the hrtimer is started
+ */
+void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
+		  enum hrtimer_mode mode)
+{
+	debug_init(timer, clock_id, mode);
+	__hrtimer_init(timer, clock_id, mode);
+}
+EXPORT_SYMBOL_GPL(hrtimer_init);
+
+/*
+ * A timer is active, when it is enqueued into the rbtree or the
+ * callback function is running or it's in the state of being migrated
+ * to another cpu.
+ *
+ * It is important for this function to not return a false negative.
+ */
+bool hrtimer_active(const struct hrtimer *timer)
+{
+	struct hrtimer_clock_base *base;
+	unsigned int seq;
+
+	do {
+		base = READ_ONCE(timer->base);
+		seq = raw_read_seqcount_begin(&base->seq);
+
+		if (timer->state != HRTIMER_STATE_INACTIVE ||
+		    base->running == timer)
+			return true;
+
+	} while (read_seqcount_retry(&base->seq, seq) ||
+		 base != READ_ONCE(timer->base));
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(hrtimer_active);
+
+/*
+ * The write_seqcount_barrier()s in __run_hrtimer() split the thing into 3
+ * distinct sections:
+ *
+ *  - queued:	the timer is queued
+ *  - callback:	the timer is being ran
+ *  - post:	the timer is inactive or (re)queued
+ *
+ * On the read side we ensure we observe timer->state and cpu_base->running
+ * from the same section, if anything changed while we looked at it, we retry.
+ * This includes timer->base changing because sequence numbers alone are
+ * insufficient for that.
+ *
+ * The sequence numbers are required because otherwise we could still observe
+ * a false negative if the read side got smeared over multiple consecutive
+ * __run_hrtimer() invocations.
+ */
+
+static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
+			  struct hrtimer_clock_base *base,
+			  struct hrtimer *timer, ktime_t *now,
+			  unsigned long flags) __must_hold(&cpu_base->lock)
+{
+	enum hrtimer_restart (*fn)(struct hrtimer *);
+	bool expires_in_hardirq;
+	int restart;
+
+	lockdep_assert_held(&cpu_base->lock);
+
+	debug_deactivate(timer);
+	base->running = timer;
+
+	/*
+	 * Separate the ->running assignment from the ->state assignment.
+	 *
+	 * As with a regular write barrier, this ensures the read side in
+	 * hrtimer_active() cannot observe base->running == NULL &&
+	 * timer->state == INACTIVE.
+	 */
+	raw_write_seqcount_barrier(&base->seq);
+
+	__remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE, 0);
+	fn = timer->function;
+
+	/*
+	 * Clear the 'is relative' flag for the TIME_LOW_RES case. If the
+	 * timer is restarted with a period then it becomes an absolute
+	 * timer. If its not restarted it does not matter.
+	 */
+	if (IS_ENABLED(CONFIG_TIME_LOW_RES))
+		timer->is_rel = false;
+
+	/*
+	 * The timer is marked as running in the CPU base, so it is
+	 * protected against migration to a different CPU even if the lock
+	 * is dropped.
+	 */
+	raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
+	trace_hrtimer_expire_entry(timer, now);
+	expires_in_hardirq = lockdep_hrtimer_enter(timer);
+
+	restart = fn(timer);
+
+	lockdep_hrtimer_exit(expires_in_hardirq);
+	trace_hrtimer_expire_exit(timer);
+	raw_spin_lock_irq(&cpu_base->lock);
+
+	/*
+	 * Note: We clear the running state after enqueue_hrtimer and
+	 * we do not reprogram the event hardware. Happens either in
+	 * hrtimer_start_range_ns() or in hrtimer_interrupt()
+	 *
+	 * Note: Because we dropped the cpu_base->lock above,
+	 * hrtimer_start_range_ns() can have popped in and enqueued the timer
+	 * for us already.
+	 */
+	if (restart != HRTIMER_NORESTART &&
+	    !(timer->state & HRTIMER_STATE_ENQUEUED))
+		enqueue_hrtimer(timer, base, HRTIMER_MODE_ABS);
+
+	/*
+	 * Separate the ->running assignment from the ->state assignment.
+	 *
+	 * As with a regular write barrier, this ensures the read side in
+	 * hrtimer_active() cannot observe base->running.timer == NULL &&
+	 * timer->state == INACTIVE.
+	 */
+	raw_write_seqcount_barrier(&base->seq);
+
+	WARN_ON_ONCE(base->running != timer);
+	base->running = NULL;
+}
+
+static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now,
+				 unsigned long flags, unsigned int active_mask)
+{
+	struct hrtimer_clock_base *base;
+	unsigned int active = cpu_base->active_bases & active_mask;
+
+	for_each_active_base(base, cpu_base, active) {
+		struct timerqueue_node *node;
+		ktime_t basenow;
+
+		basenow = ktime_add(now, base->offset);
+
+		while ((node = timerqueue_getnext(&base->active))) {
+			struct hrtimer *timer;
+
+			timer = container_of(node, struct hrtimer, node);
+
+			/*
+			 * The immediate goal for using the softexpires is
+			 * minimizing wakeups, not running timers at the
+			 * earliest interrupt after their soft expiration.
+			 * This allows us to avoid using a Priority Search
+			 * Tree, which can answer a stabbing query for
+			 * overlapping intervals and instead use the simple
+			 * BST we already have.
+			 * We don't add extra wakeups by delaying timers that
+			 * are right-of a not yet expired timer, because that
+			 * timer will have to trigger a wakeup anyway.
+			 */
+			if (basenow < hrtimer_get_softexpires_tv64(timer))
+				break;
+
+			__run_hrtimer(cpu_base, base, timer, &basenow, flags);
+			if (active_mask == HRTIMER_ACTIVE_SOFT)
+				hrtimer_sync_wait_running(cpu_base, flags);
+		}
+	}
+}
+
+static __latent_entropy void hrtimer_run_softirq(struct softirq_action *h)
+{
+	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
+	unsigned long flags;
+	ktime_t now;
+
+	hrtimer_cpu_base_lock_expiry(cpu_base);
+	raw_spin_lock_irqsave(&cpu_base->lock, flags);
+
+	now = hrtimer_update_base(cpu_base);
+	__hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_SOFT);
+
+	cpu_base->softirq_activated = 0;
+	hrtimer_update_softirq_timer(cpu_base, true);
+
+	raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
+	hrtimer_cpu_base_unlock_expiry(cpu_base);
+}
+
+#ifdef CONFIG_HIGH_RES_TIMERS
+
+/*
+ * High resolution timer interrupt
+ * Called with interrupts disabled
+ */
+void hrtimer_interrupt(struct clock_event_device *dev)
+{
+	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
+	ktime_t expires_next, now, entry_time, delta;
+	unsigned long flags;
+	int retries = 0;
+
+	BUG_ON(!cpu_base->hres_active);
+	cpu_base->nr_events++;
+	dev->next_event = KTIME_MAX;
+
+	raw_spin_lock_irqsave(&cpu_base->lock, flags);
+	entry_time = now = hrtimer_update_base(cpu_base);
+retry:
+	cpu_base->in_hrtirq = 1;
+	/*
+	 * We set expires_next to KTIME_MAX here with cpu_base->lock
+	 * held to prevent that a timer is enqueued in our queue via
+	 * the migration code. This does not affect enqueueing of
+	 * timers which run their callback and need to be requeued on
+	 * this CPU.
+	 */
+	cpu_base->expires_next = KTIME_MAX;
+
+	if (!ktime_before(now, cpu_base->softirq_expires_next)) {
+		cpu_base->softirq_expires_next = KTIME_MAX;
+		cpu_base->softirq_activated = 1;
+		raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+	}
+
+	__hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_HARD);
+
+	/* Reevaluate the clock bases for the [soft] next expiry */
+	expires_next = hrtimer_update_next_event(cpu_base);
+	/*
+	 * Store the new expiry value so the migration code can verify
+	 * against it.
+	 */
+	cpu_base->expires_next = expires_next;
+	cpu_base->in_hrtirq = 0;
+	raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
+
+	/* Reprogramming necessary ? */
+	if (!tick_program_event(expires_next, 0)) {
+		cpu_base->hang_detected = 0;
+		return;
+	}
+
+	/*
+	 * The next timer was already expired due to:
+	 * - tracing
+	 * - long lasting callbacks
+	 * - being scheduled away when running in a VM
+	 *
+	 * We need to prevent that we loop forever in the hrtimer
+	 * interrupt routine. We give it 3 attempts to avoid
+	 * overreacting on some spurious event.
+	 *
+	 * Acquire base lock for updating the offsets and retrieving
+	 * the current time.
+	 */
+	raw_spin_lock_irqsave(&cpu_base->lock, flags);
+	now = hrtimer_update_base(cpu_base);
+	cpu_base->nr_retries++;
+	if (++retries < 3)
+		goto retry;
+	/*
+	 * Give the system a chance to do something else than looping
+	 * here. We stored the entry time, so we know exactly how long
+	 * we spent here. We schedule the next event this amount of
+	 * time away.
+	 */
+	cpu_base->nr_hangs++;
+	cpu_base->hang_detected = 1;
+	raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
+
+	delta = ktime_sub(now, entry_time);
+	if ((unsigned int)delta > cpu_base->max_hang_time)
+		cpu_base->max_hang_time = (unsigned int) delta;
+	/*
+	 * Limit it to a sensible value as we enforce a longer
+	 * delay. Give the CPU at least 100ms to catch up.
+	 */
+	if (delta > 100 * NSEC_PER_MSEC)
+		expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
+	else
+		expires_next = ktime_add(now, delta);
+	tick_program_event(expires_next, 1);
+	pr_warn_once("hrtimer: interrupt took %llu ns\n", ktime_to_ns(delta));
+}
+
+/* called with interrupts disabled */
+static inline void __hrtimer_peek_ahead_timers(void)
+{
+	struct tick_device *td;
+
+	if (!hrtimer_hres_active())
+		return;
+
+	td = this_cpu_ptr(&tick_cpu_device);
+	if (td && td->evtdev)
+		hrtimer_interrupt(td->evtdev);
+}
+
+#else /* CONFIG_HIGH_RES_TIMERS */
+
+static inline void __hrtimer_peek_ahead_timers(void) { }
+
+#endif	/* !CONFIG_HIGH_RES_TIMERS */
+
+/*
+ * Called from run_local_timers in hardirq context every jiffy
+ */
+void hrtimer_run_queues(void)
+{
+	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
+	unsigned long flags;
+	ktime_t now;
+
+	if (__hrtimer_hres_active(cpu_base))
+		return;
+
+	/*
+	 * This _is_ ugly: We have to check periodically, whether we
+	 * can switch to highres and / or nohz mode. The clocksource
+	 * switch happens with xtime_lock held. Notification from
+	 * there only sets the check bit in the tick_oneshot code,
+	 * otherwise we might deadlock vs. xtime_lock.
+	 */
+	if (tick_check_oneshot_change(!hrtimer_is_hres_enabled())) {
+		hrtimer_switch_to_hres();
+		return;
+	}
+
+	raw_spin_lock_irqsave(&cpu_base->lock, flags);
+	now = hrtimer_update_base(cpu_base);
+
+	if (!ktime_before(now, cpu_base->softirq_expires_next)) {
+		cpu_base->softirq_expires_next = KTIME_MAX;
+		cpu_base->softirq_activated = 1;
+		raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+	}
+
+	__hrtimer_run_queues(cpu_base, now, flags, HRTIMER_ACTIVE_HARD);
+	raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
+}
+
+/*
+ * Sleep related functions:
+ */
+static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
+{
+	struct hrtimer_sleeper *t =
+		container_of(timer, struct hrtimer_sleeper, timer);
+	struct task_struct *task = t->task;
+
+	t->task = NULL;
+	if (task)
+		wake_up_process(task);
+
+	return HRTIMER_NORESTART;
+}
+
+/**
+ * hrtimer_sleeper_start_expires - Start a hrtimer sleeper timer
+ * @sl:		sleeper to be started
+ * @mode:	timer mode abs/rel
+ *
+ * Wrapper around hrtimer_start_expires() for hrtimer_sleeper based timers
+ * to allow PREEMPT_RT to tweak the delivery mode (soft/hardirq context)
+ */
+void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl,
+				   enum hrtimer_mode mode)
+{
+	/*
+	 * Make the enqueue delivery mode check work on RT. If the sleeper
+	 * was initialized for hard interrupt delivery, force the mode bit.
+	 * This is a special case for hrtimer_sleepers because
+	 * hrtimer_init_sleeper() determines the delivery mode on RT so the
+	 * fiddling with this decision is avoided at the call sites.
+	 */
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && sl->timer.is_hard)
+		mode |= HRTIMER_MODE_HARD;
+
+	hrtimer_start_expires(&sl->timer, mode);
+}
+EXPORT_SYMBOL_GPL(hrtimer_sleeper_start_expires);
+
+static void __hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
+				   clockid_t clock_id, enum hrtimer_mode mode)
+{
+	/*
+	 * On PREEMPT_RT enabled kernels hrtimers which are not explicitly
+	 * marked for hard interrupt expiry mode are moved into soft
+	 * interrupt context either for latency reasons or because the
+	 * hrtimer callback takes regular spinlocks or invokes other
+	 * functions which are not suitable for hard interrupt context on
+	 * PREEMPT_RT.
+	 *
+	 * The hrtimer_sleeper callback is RT compatible in hard interrupt
+	 * context, but there is a latency concern: Untrusted userspace can
+	 * spawn many threads which arm timers for the same expiry time on
+	 * the same CPU. That causes a latency spike due to the wakeup of
+	 * a gazillion threads.
+	 *
+	 * OTOH, privileged real-time user space applications rely on the
+	 * low latency of hard interrupt wakeups. If the current task is in
+	 * a real-time scheduling class, mark the mode for hard interrupt
+	 * expiry.
+	 */
+	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+		if (task_is_realtime(current) && !(mode & HRTIMER_MODE_SOFT))
+			mode |= HRTIMER_MODE_HARD;
+	}
+
+	__hrtimer_init(&sl->timer, clock_id, mode);
+	sl->timer.function = hrtimer_wakeup;
+	sl->task = current;
+}
+
+/**
+ * hrtimer_init_sleeper - initialize sleeper to the given clock
+ * @sl:		sleeper to be initialized
+ * @clock_id:	the clock to be used
+ * @mode:	timer mode abs/rel
+ */
+void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, clockid_t clock_id,
+			  enum hrtimer_mode mode)
+{
+	debug_init(&sl->timer, clock_id, mode);
+	__hrtimer_init_sleeper(sl, clock_id, mode);
+
+}
+EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
+
+int nanosleep_copyout(struct restart_block *restart, struct timespec64 *ts)
+{
+	switch(restart->nanosleep.type) {
+#ifdef CONFIG_COMPAT_32BIT_TIME
+	case TT_COMPAT:
+		if (put_old_timespec32(ts, restart->nanosleep.compat_rmtp))
+			return -EFAULT;
+		break;
+#endif
+	case TT_NATIVE:
+		if (put_timespec64(ts, restart->nanosleep.rmtp))
+			return -EFAULT;
+		break;
+	default:
+		BUG();
+	}
+	return -ERESTART_RESTARTBLOCK;
+}
+
+static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
+{
+	struct restart_block *restart;
+
+	do {
+		set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
+		hrtimer_sleeper_start_expires(t, mode);
+
+		if (likely(t->task))
+			schedule();
+
+		hrtimer_cancel(&t->timer);
+		mode = HRTIMER_MODE_ABS;
+
+	} while (t->task && !signal_pending(current));
+
+	__set_current_state(TASK_RUNNING);
+
+	if (!t->task)
+		return 0;
+
+	restart = &current->restart_block;
+	if (restart->nanosleep.type != TT_NONE) {
+		ktime_t rem = hrtimer_expires_remaining(&t->timer);
+		struct timespec64 rmt;
+
+		if (rem <= 0)
+			return 0;
+		rmt = ktime_to_timespec64(rem);
+
+		return nanosleep_copyout(restart, &rmt);
+	}
+	return -ERESTART_RESTARTBLOCK;
+}
+
+static long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
+{
+	struct hrtimer_sleeper t;
+	int ret;
+
+	hrtimer_init_sleeper_on_stack(&t, restart->nanosleep.clockid,
+				      HRTIMER_MODE_ABS);
+	hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
+	ret = do_nanosleep(&t, HRTIMER_MODE_ABS);
+	destroy_hrtimer_on_stack(&t.timer);
+	return ret;
+}
+
+long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode,
+		       const clockid_t clockid)
+{
+	struct restart_block *restart;
+	struct hrtimer_sleeper t;
+	int ret = 0;
+	u64 slack;
+
+	slack = current->timer_slack_ns;
+	if (dl_task(current) || rt_task(current))
+		slack = 0;
+
+	hrtimer_init_sleeper_on_stack(&t, clockid, mode);
+	hrtimer_set_expires_range_ns(&t.timer, rqtp, slack);
+	ret = do_nanosleep(&t, mode);
+	if (ret != -ERESTART_RESTARTBLOCK)
+		goto out;
+
+	/* Absolute timers do not update the rmtp value and restart: */
+	if (mode == HRTIMER_MODE_ABS) {
+		ret = -ERESTARTNOHAND;
+		goto out;
+	}
+
+	restart = &current->restart_block;
+	restart->nanosleep.clockid = t.timer.base->clockid;
+	restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
+	set_restart_fn(restart, hrtimer_nanosleep_restart);
+out:
+	destroy_hrtimer_on_stack(&t.timer);
+	return ret;
+}
+
+#ifdef CONFIG_64BIT
+
+SYSCALL_DEFINE2(nanosleep, struct __kernel_timespec __user *, rqtp,
+		struct __kernel_timespec __user *, rmtp)
+{
+	struct timespec64 tu;
+
+	if (get_timespec64(&tu, rqtp))
+		return -EFAULT;
+
+	if (!timespec64_valid(&tu))
+		return -EINVAL;
+
+	current->restart_block.fn = do_no_restart_syscall;
+	current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
+	current->restart_block.nanosleep.rmtp = rmtp;
+	return hrtimer_nanosleep(timespec64_to_ktime(tu), HRTIMER_MODE_REL,
+				 CLOCK_MONOTONIC);
+}
+
+#endif
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+
+SYSCALL_DEFINE2(nanosleep_time32, struct old_timespec32 __user *, rqtp,
+		       struct old_timespec32 __user *, rmtp)
+{
+	struct timespec64 tu;
+
+	if (get_old_timespec32(&tu, rqtp))
+		return -EFAULT;
+
+	if (!timespec64_valid(&tu))
+		return -EINVAL;
+
+	current->restart_block.fn = do_no_restart_syscall;
+	current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
+	current->restart_block.nanosleep.compat_rmtp = rmtp;
+	return hrtimer_nanosleep(timespec64_to_ktime(tu), HRTIMER_MODE_REL,
+				 CLOCK_MONOTONIC);
+}
+#endif
+
+/*
+ * Functions related to boot-time initialization:
+ */
+int hrtimers_prepare_cpu(unsigned int cpu)
+{
+	struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
+	int i;
+
+	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
+		struct hrtimer_clock_base *clock_b = &cpu_base->clock_base[i];
+
+		clock_b->cpu_base = cpu_base;
+		seqcount_raw_spinlock_init(&clock_b->seq, &cpu_base->lock);
+		timerqueue_init_head(&clock_b->active);
+	}
+
+	cpu_base->cpu = cpu;
+	cpu_base->active_bases = 0;
+	cpu_base->hres_active = 0;
+	cpu_base->hang_detected = 0;
+	cpu_base->next_timer = NULL;
+	cpu_base->softirq_next_timer = NULL;
+	cpu_base->expires_next = KTIME_MAX;
+	cpu_base->softirq_expires_next = KTIME_MAX;
+	hrtimer_cpu_base_init_expiry_lock(cpu_base);
+	return 0;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
+				struct hrtimer_clock_base *new_base)
+{
+	struct hrtimer *timer;
+	struct timerqueue_node *node;
+
+	while ((node = timerqueue_getnext(&old_base->active))) {
+		timer = container_of(node, struct hrtimer, node);
+		BUG_ON(hrtimer_callback_running(timer));
+		debug_deactivate(timer);
+
+		/*
+		 * Mark it as ENQUEUED not INACTIVE otherwise the
+		 * timer could be seen as !active and just vanish away
+		 * under us on another CPU
+		 */
+		__remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0);
+		timer->base = new_base;
+		/*
+		 * Enqueue the timers on the new cpu. This does not
+		 * reprogram the event device in case the timer
+		 * expires before the earliest on this CPU, but we run
+		 * hrtimer_interrupt after we migrated everything to
+		 * sort out already expired timers and reprogram the
+		 * event device.
+		 */
+		enqueue_hrtimer(timer, new_base, HRTIMER_MODE_ABS);
+	}
+}
+
+int hrtimers_cpu_dying(unsigned int dying_cpu)
+{
+	struct hrtimer_cpu_base *old_base, *new_base;
+	int i, ncpu = cpumask_first(cpu_active_mask);
+
+	tick_cancel_sched_timer(dying_cpu);
+
+	old_base = this_cpu_ptr(&hrtimer_bases);
+	new_base = &per_cpu(hrtimer_bases, ncpu);
+
+	/*
+	 * The caller is globally serialized and nobody else
+	 * takes two locks at once, deadlock is not possible.
+	 */
+	raw_spin_lock(&old_base->lock);
+	raw_spin_lock_nested(&new_base->lock, SINGLE_DEPTH_NESTING);
+
+	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
+		migrate_hrtimer_list(&old_base->clock_base[i],
+				     &new_base->clock_base[i]);
+	}
+
+	/*
+	 * The migration might have changed the first expiring softirq
+	 * timer on this CPU. Update it.
+	 */
+	__hrtimer_get_next_event(new_base, HRTIMER_ACTIVE_SOFT);
+	/* Tell the other CPU to retrigger the next event */
+	smp_call_function_single(ncpu, retrigger_next_event, NULL, 0);
+
+	raw_spin_unlock(&new_base->lock);
+	raw_spin_unlock(&old_base->lock);
+
+	return 0;
+}
+
+#endif /* CONFIG_HOTPLUG_CPU */
+
+void __init hrtimers_init(void)
+{
+	hrtimers_prepare_cpu(smp_processor_id());
+	open_softirq(HRTIMER_SOFTIRQ, hrtimer_run_softirq);
+}
+
+/**
+ * schedule_hrtimeout_range_clock - sleep until timeout
+ * @expires:	timeout value (ktime_t)
+ * @delta:	slack in expires timeout (ktime_t)
+ * @mode:	timer mode
+ * @clock_id:	timer clock to be used
+ */
+int __sched
+schedule_hrtimeout_range_clock(ktime_t *expires, u64 delta,
+			       const enum hrtimer_mode mode, clockid_t clock_id)
+{
+	struct hrtimer_sleeper t;
+
+	/*
+	 * Optimize when a zero timeout value is given. It does not
+	 * matter whether this is an absolute or a relative time.
+	 */
+	if (expires && *expires == 0) {
+		__set_current_state(TASK_RUNNING);
+		return 0;
+	}
+
+	/*
+	 * A NULL parameter means "infinite"
+	 */
+	if (!expires) {
+		schedule();
+		return -EINTR;
+	}
+
+	hrtimer_init_sleeper_on_stack(&t, clock_id, mode);
+	hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
+	hrtimer_sleeper_start_expires(&t, mode);
+
+	if (likely(t.task))
+		schedule();
+
+	hrtimer_cancel(&t.timer);
+	destroy_hrtimer_on_stack(&t.timer);
+
+	__set_current_state(TASK_RUNNING);
+
+	return !t.task ? 0 : -EINTR;
+}
+EXPORT_SYMBOL_GPL(schedule_hrtimeout_range_clock);
+
+/**
+ * schedule_hrtimeout_range - sleep until timeout
+ * @expires:	timeout value (ktime_t)
+ * @delta:	slack in expires timeout (ktime_t)
+ * @mode:	timer mode
+ *
+ * Make the current task sleep until the given expiry time has
+ * elapsed. The routine will return immediately unless
+ * the current task state has been set (see set_current_state()).
+ *
+ * The @delta argument gives the kernel the freedom to schedule the
+ * actual wakeup to a time that is both power and performance friendly.
+ * The kernel give the normal best effort behavior for "@expires+@delta",
+ * but may decide to fire the timer earlier, but no earlier than @expires.
+ *
+ * You can set the task state as follows -
+ *
+ * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
+ * pass before the routine returns unless the current task is explicitly
+ * woken up, (e.g. by wake_up_process()).
+ *
+ * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
+ * delivered to the current task or the current task is explicitly woken
+ * up.
+ *
+ * The current task state is guaranteed to be TASK_RUNNING when this
+ * routine returns.
+ *
+ * Returns 0 when the timer has expired. If the task was woken before the
+ * timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or
+ * by an explicit wakeup, it returns -EINTR.
+ */
+int __sched schedule_hrtimeout_range(ktime_t *expires, u64 delta,
+				     const enum hrtimer_mode mode)
+{
+	return schedule_hrtimeout_range_clock(expires, delta, mode,
+					      CLOCK_MONOTONIC);
+}
+EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
+
+/**
+ * schedule_hrtimeout - sleep until timeout
+ * @expires:	timeout value (ktime_t)
+ * @mode:	timer mode
+ *
+ * Make the current task sleep until the given expiry time has
+ * elapsed. The routine will return immediately unless
+ * the current task state has been set (see set_current_state()).
+ *
+ * You can set the task state as follows -
+ *
+ * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
+ * pass before the routine returns unless the current task is explicitly
+ * woken up, (e.g. by wake_up_process()).
+ *
+ * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
+ * delivered to the current task or the current task is explicitly woken
+ * up.
+ *
+ * The current task state is guaranteed to be TASK_RUNNING when this
+ * routine returns.
+ *
+ * Returns 0 when the timer has expired. If the task was woken before the
+ * timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or
+ * by an explicit wakeup, it returns -EINTR.
+ */
+int __sched schedule_hrtimeout(ktime_t *expires,
+			       const enum hrtimer_mode mode)
+{
+	return schedule_hrtimeout_range(expires, 0, mode);
+}
+EXPORT_SYMBOL_GPL(schedule_hrtimeout);
diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c
new file mode 100644
index 000000000..00629e658
--- /dev/null
+++ b/kernel/time/itimer.c
@@ -0,0 +1,403 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1992 Darren Senn
+ */
+
+/* These are all the functions necessary to implement itimers */
+
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/syscalls.h>
+#include <linux/time.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/cputime.h>
+#include <linux/posix-timers.h>
+#include <linux/hrtimer.h>
+#include <trace/events/timer.h>
+#include <linux/compat.h>
+
+#include <linux/uaccess.h>
+
+/**
+ * itimer_get_remtime - get remaining time for the timer
+ *
+ * @timer: the timer to read
+ *
+ * Returns the delta between the expiry time and now, which can be
+ * less than zero or 1usec for an pending expired timer
+ */
+static struct timespec64 itimer_get_remtime(struct hrtimer *timer)
+{
+	ktime_t rem = __hrtimer_get_remaining(timer, true);
+
+	/*
+	 * Racy but safe: if the itimer expires after the above
+	 * hrtimer_get_remtime() call but before this condition
+	 * then we return 0 - which is correct.
+	 */
+	if (hrtimer_active(timer)) {
+		if (rem <= 0)
+			rem = NSEC_PER_USEC;
+	} else
+		rem = 0;
+
+	return ktime_to_timespec64(rem);
+}
+
+static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
+			   struct itimerspec64 *const value)
+{
+	u64 val, interval;
+	struct cpu_itimer *it = &tsk->signal->it[clock_id];
+
+	spin_lock_irq(&tsk->sighand->siglock);
+
+	val = it->expires;
+	interval = it->incr;
+	if (val) {
+		u64 t, samples[CPUCLOCK_MAX];
+
+		thread_group_sample_cputime(tsk, samples);
+		t = samples[clock_id];
+
+		if (val < t)
+			/* about to fire */
+			val = TICK_NSEC;
+		else
+			val -= t;
+	}
+
+	spin_unlock_irq(&tsk->sighand->siglock);
+
+	value->it_value = ns_to_timespec64(val);
+	value->it_interval = ns_to_timespec64(interval);
+}
+
+static int do_getitimer(int which, struct itimerspec64 *value)
+{
+	struct task_struct *tsk = current;
+
+	switch (which) {
+	case ITIMER_REAL:
+		spin_lock_irq(&tsk->sighand->siglock);
+		value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
+		value->it_interval =
+			ktime_to_timespec64(tsk->signal->it_real_incr);
+		spin_unlock_irq(&tsk->sighand->siglock);
+		break;
+	case ITIMER_VIRTUAL:
+		get_cpu_itimer(tsk, CPUCLOCK_VIRT, value);
+		break;
+	case ITIMER_PROF:
+		get_cpu_itimer(tsk, CPUCLOCK_PROF, value);
+		break;
+	default:
+		return(-EINVAL);
+	}
+	return 0;
+}
+
+static int put_itimerval(struct __kernel_old_itimerval __user *o,
+			 const struct itimerspec64 *i)
+{
+	struct __kernel_old_itimerval v;
+
+	v.it_interval.tv_sec = i->it_interval.tv_sec;
+	v.it_interval.tv_usec = i->it_interval.tv_nsec / NSEC_PER_USEC;
+	v.it_value.tv_sec = i->it_value.tv_sec;
+	v.it_value.tv_usec = i->it_value.tv_nsec / NSEC_PER_USEC;
+	return copy_to_user(o, &v, sizeof(struct __kernel_old_itimerval)) ? -EFAULT : 0;
+}
+
+
+SYSCALL_DEFINE2(getitimer, int, which, struct __kernel_old_itimerval __user *, value)
+{
+	struct itimerspec64 get_buffer;
+	int error = do_getitimer(which, &get_buffer);
+
+	if (!error && put_itimerval(value, &get_buffer))
+		error = -EFAULT;
+	return error;
+}
+
+#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA)
+struct old_itimerval32 {
+	struct old_timeval32	it_interval;
+	struct old_timeval32	it_value;
+};
+
+static int put_old_itimerval32(struct old_itimerval32 __user *o,
+			       const struct itimerspec64 *i)
+{
+	struct old_itimerval32 v32;
+
+	v32.it_interval.tv_sec = i->it_interval.tv_sec;
+	v32.it_interval.tv_usec = i->it_interval.tv_nsec / NSEC_PER_USEC;
+	v32.it_value.tv_sec = i->it_value.tv_sec;
+	v32.it_value.tv_usec = i->it_value.tv_nsec / NSEC_PER_USEC;
+	return copy_to_user(o, &v32, sizeof(struct old_itimerval32)) ? -EFAULT : 0;
+}
+
+COMPAT_SYSCALL_DEFINE2(getitimer, int, which,
+		       struct old_itimerval32 __user *, value)
+{
+	struct itimerspec64 get_buffer;
+	int error = do_getitimer(which, &get_buffer);
+
+	if (!error && put_old_itimerval32(value, &get_buffer))
+		error = -EFAULT;
+	return error;
+}
+#endif
+
+/*
+ * The timer is automagically restarted, when interval != 0
+ */
+enum hrtimer_restart it_real_fn(struct hrtimer *timer)
+{
+	struct signal_struct *sig =
+		container_of(timer, struct signal_struct, real_timer);
+	struct pid *leader_pid = sig->pids[PIDTYPE_TGID];
+
+	trace_itimer_expire(ITIMER_REAL, leader_pid, 0);
+	kill_pid_info(SIGALRM, SEND_SIG_PRIV, leader_pid);
+
+	return HRTIMER_NORESTART;
+}
+
+static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
+			   const struct itimerspec64 *const value,
+			   struct itimerspec64 *const ovalue)
+{
+	u64 oval, nval, ointerval, ninterval;
+	struct cpu_itimer *it = &tsk->signal->it[clock_id];
+
+	nval = timespec64_to_ns(&value->it_value);
+	ninterval = timespec64_to_ns(&value->it_interval);
+
+	spin_lock_irq(&tsk->sighand->siglock);
+
+	oval = it->expires;
+	ointerval = it->incr;
+	if (oval || nval) {
+		if (nval > 0)
+			nval += TICK_NSEC;
+		set_process_cpu_timer(tsk, clock_id, &nval, &oval);
+	}
+	it->expires = nval;
+	it->incr = ninterval;
+	trace_itimer_state(clock_id == CPUCLOCK_VIRT ?
+			   ITIMER_VIRTUAL : ITIMER_PROF, value, nval);
+
+	spin_unlock_irq(&tsk->sighand->siglock);
+
+	if (ovalue) {
+		ovalue->it_value = ns_to_timespec64(oval);
+		ovalue->it_interval = ns_to_timespec64(ointerval);
+	}
+}
+
+/*
+ * Returns true if the timeval is in canonical form
+ */
+#define timeval_valid(t) \
+	(((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
+
+static int do_setitimer(int which, struct itimerspec64 *value,
+			struct itimerspec64 *ovalue)
+{
+	struct task_struct *tsk = current;
+	struct hrtimer *timer;
+	ktime_t expires;
+
+	switch (which) {
+	case ITIMER_REAL:
+again:
+		spin_lock_irq(&tsk->sighand->siglock);
+		timer = &tsk->signal->real_timer;
+		if (ovalue) {
+			ovalue->it_value = itimer_get_remtime(timer);
+			ovalue->it_interval
+				= ktime_to_timespec64(tsk->signal->it_real_incr);
+		}
+		/* We are sharing ->siglock with it_real_fn() */
+		if (hrtimer_try_to_cancel(timer) < 0) {
+			spin_unlock_irq(&tsk->sighand->siglock);
+			hrtimer_cancel_wait_running(timer);
+			goto again;
+		}
+		expires = timespec64_to_ktime(value->it_value);
+		if (expires != 0) {
+			tsk->signal->it_real_incr =
+				timespec64_to_ktime(value->it_interval);
+			hrtimer_start(timer, expires, HRTIMER_MODE_REL);
+		} else
+			tsk->signal->it_real_incr = 0;
+
+		trace_itimer_state(ITIMER_REAL, value, 0);
+		spin_unlock_irq(&tsk->sighand->siglock);
+		break;
+	case ITIMER_VIRTUAL:
+		set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue);
+		break;
+	case ITIMER_PROF:
+		set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue);
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+#ifdef CONFIG_SECURITY_SELINUX
+void clear_itimer(void)
+{
+	struct itimerspec64 v = {};
+	int i;
+
+	for (i = 0; i < 3; i++)
+		do_setitimer(i, &v, NULL);
+}
+#endif
+
+#ifdef __ARCH_WANT_SYS_ALARM
+
+/**
+ * alarm_setitimer - set alarm in seconds
+ *
+ * @seconds:	number of seconds until alarm
+ *		0 disables the alarm
+ *
+ * Returns the remaining time in seconds of a pending timer or 0 when
+ * the timer is not active.
+ *
+ * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
+ * negative timeval settings which would cause immediate expiry.
+ */
+static unsigned int alarm_setitimer(unsigned int seconds)
+{
+	struct itimerspec64 it_new, it_old;
+
+#if BITS_PER_LONG < 64
+	if (seconds > INT_MAX)
+		seconds = INT_MAX;
+#endif
+	it_new.it_value.tv_sec = seconds;
+	it_new.it_value.tv_nsec = 0;
+	it_new.it_interval.tv_sec = it_new.it_interval.tv_nsec = 0;
+
+	do_setitimer(ITIMER_REAL, &it_new, &it_old);
+
+	/*
+	 * We can't return 0 if we have an alarm pending ...  And we'd
+	 * better return too much than too little anyway
+	 */
+	if ((!it_old.it_value.tv_sec && it_old.it_value.tv_nsec) ||
+	      it_old.it_value.tv_nsec >= (NSEC_PER_SEC / 2))
+		it_old.it_value.tv_sec++;
+
+	return it_old.it_value.tv_sec;
+}
+
+/*
+ * For backwards compatibility?  This can be done in libc so Alpha
+ * and all newer ports shouldn't need it.
+ */
+SYSCALL_DEFINE1(alarm, unsigned int, seconds)
+{
+	return alarm_setitimer(seconds);
+}
+
+#endif
+
+static int get_itimerval(struct itimerspec64 *o, const struct __kernel_old_itimerval __user *i)
+{
+	struct __kernel_old_itimerval v;
+
+	if (copy_from_user(&v, i, sizeof(struct __kernel_old_itimerval)))
+		return -EFAULT;
+
+	/* Validate the timevals in value. */
+	if (!timeval_valid(&v.it_value) ||
+	    !timeval_valid(&v.it_interval))
+		return -EINVAL;
+
+	o->it_interval.tv_sec = v.it_interval.tv_sec;
+	o->it_interval.tv_nsec = v.it_interval.tv_usec * NSEC_PER_USEC;
+	o->it_value.tv_sec = v.it_value.tv_sec;
+	o->it_value.tv_nsec = v.it_value.tv_usec * NSEC_PER_USEC;
+	return 0;
+}
+
+SYSCALL_DEFINE3(setitimer, int, which, struct __kernel_old_itimerval __user *, value,
+		struct __kernel_old_itimerval __user *, ovalue)
+{
+	struct itimerspec64 set_buffer, get_buffer;
+	int error;
+
+	if (value) {
+		error = get_itimerval(&set_buffer, value);
+		if (error)
+			return error;
+	} else {
+		memset(&set_buffer, 0, sizeof(set_buffer));
+		printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer."
+			    " Misfeature support will be removed\n",
+			    current->comm);
+	}
+
+	error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
+	if (error || !ovalue)
+		return error;
+
+	if (put_itimerval(ovalue, &get_buffer))
+		return -EFAULT;
+	return 0;
+}
+
+#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA)
+static int get_old_itimerval32(struct itimerspec64 *o, const struct old_itimerval32 __user *i)
+{
+	struct old_itimerval32 v32;
+
+	if (copy_from_user(&v32, i, sizeof(struct old_itimerval32)))
+		return -EFAULT;
+
+	/* Validate the timevals in value.  */
+	if (!timeval_valid(&v32.it_value) ||
+	    !timeval_valid(&v32.it_interval))
+		return -EINVAL;
+
+	o->it_interval.tv_sec = v32.it_interval.tv_sec;
+	o->it_interval.tv_nsec = v32.it_interval.tv_usec * NSEC_PER_USEC;
+	o->it_value.tv_sec = v32.it_value.tv_sec;
+	o->it_value.tv_nsec = v32.it_value.tv_usec * NSEC_PER_USEC;
+	return 0;
+}
+
+COMPAT_SYSCALL_DEFINE3(setitimer, int, which,
+		       struct old_itimerval32 __user *, value,
+		       struct old_itimerval32 __user *, ovalue)
+{
+	struct itimerspec64 set_buffer, get_buffer;
+	int error;
+
+	if (value) {
+		error = get_old_itimerval32(&set_buffer, value);
+		if (error)
+			return error;
+	} else {
+		memset(&set_buffer, 0, sizeof(set_buffer));
+		printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer."
+			    " Misfeature support will be removed\n",
+			    current->comm);
+	}
+
+	error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
+	if (error || !ovalue)
+		return error;
+	if (put_old_itimerval32(ovalue, &get_buffer))
+		return -EFAULT;
+	return 0;
+}
+#endif
diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c
new file mode 100644
index 000000000..bc4db9e5a
--- /dev/null
+++ b/kernel/time/jiffies.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * This file contains the jiffies based clocksource.
+ *
+ * Copyright (C) 2004, 2005 IBM, John Stultz (johnstul@us.ibm.com)
+ */
+#include <linux/clocksource.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include "timekeeping.h"
+#include "tick-internal.h"
+
+
+static u64 jiffies_read(struct clocksource *cs)
+{
+	return (u64) jiffies;
+}
+
+/*
+ * The Jiffies based clocksource is the lowest common
+ * denominator clock source which should function on
+ * all systems. It has the same coarse resolution as
+ * the timer interrupt frequency HZ and it suffers
+ * inaccuracies caused by missed or lost timer
+ * interrupts and the inability for the timer
+ * interrupt hardware to accurately tick at the
+ * requested HZ value. It is also not recommended
+ * for "tick-less" systems.
+ */
+static struct clocksource clocksource_jiffies = {
+	.name			= "jiffies",
+	.rating			= 1, /* lowest valid rating*/
+	.uncertainty_margin	= 32 * NSEC_PER_MSEC,
+	.read			= jiffies_read,
+	.mask			= CLOCKSOURCE_MASK(32),
+	.mult			= TICK_NSEC << JIFFIES_SHIFT, /* details above */
+	.shift			= JIFFIES_SHIFT,
+	.max_cycles		= 10,
+};
+
+__cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(jiffies_lock);
+__cacheline_aligned_in_smp seqcount_raw_spinlock_t jiffies_seq =
+	SEQCNT_RAW_SPINLOCK_ZERO(jiffies_seq, &jiffies_lock);
+
+#if (BITS_PER_LONG < 64)
+u64 get_jiffies_64(void)
+{
+	unsigned int seq;
+	u64 ret;
+
+	do {
+		seq = read_seqcount_begin(&jiffies_seq);
+		ret = jiffies_64;
+	} while (read_seqcount_retry(&jiffies_seq, seq));
+	return ret;
+}
+EXPORT_SYMBOL(get_jiffies_64);
+#endif
+
+EXPORT_SYMBOL(jiffies);
+
+static int __init init_jiffies_clocksource(void)
+{
+	return __clocksource_register(&clocksource_jiffies);
+}
+
+core_initcall(init_jiffies_clocksource);
+
+struct clocksource * __init __weak clocksource_default_clock(void)
+{
+	return &clocksource_jiffies;
+}
+
+static struct clocksource refined_jiffies;
+
+int register_refined_jiffies(long cycles_per_second)
+{
+	u64 nsec_per_tick, shift_hz;
+	long cycles_per_tick;
+
+
+
+	refined_jiffies = clocksource_jiffies;
+	refined_jiffies.name = "refined-jiffies";
+	refined_jiffies.rating++;
+
+	/* Calc cycles per tick */
+	cycles_per_tick = (cycles_per_second + HZ/2)/HZ;
+	/* shift_hz stores hz<<8 for extra accuracy */
+	shift_hz = (u64)cycles_per_second << 8;
+	shift_hz += cycles_per_tick/2;
+	do_div(shift_hz, cycles_per_tick);
+	/* Calculate nsec_per_tick using shift_hz */
+	nsec_per_tick = (u64)NSEC_PER_SEC << 8;
+	nsec_per_tick += (u32)shift_hz/2;
+	do_div(nsec_per_tick, (u32)shift_hz);
+
+	refined_jiffies.mult = ((u32)nsec_per_tick) << JIFFIES_SHIFT;
+
+	__clocksource_register(&refined_jiffies);
+	return 0;
+}
diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
new file mode 100644
index 000000000..aec832801
--- /dev/null
+++ b/kernel/time/namespace.c
@@ -0,0 +1,467 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Author: Andrei Vagin <avagin@openvz.org>
+ * Author: Dmitry Safonov <dima@arista.com>
+ */
+
+#include <linux/time_namespace.h>
+#include <linux/user_namespace.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/task.h>
+#include <linux/clocksource.h>
+#include <linux/seq_file.h>
+#include <linux/proc_ns.h>
+#include <linux/export.h>
+#include <linux/time.h>
+#include <linux/slab.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+
+#include <vdso/datapage.h>
+
+ktime_t do_timens_ktime_to_host(clockid_t clockid, ktime_t tim,
+				struct timens_offsets *ns_offsets)
+{
+	ktime_t offset;
+
+	switch (clockid) {
+	case CLOCK_MONOTONIC:
+		offset = timespec64_to_ktime(ns_offsets->monotonic);
+		break;
+	case CLOCK_BOOTTIME:
+	case CLOCK_BOOTTIME_ALARM:
+		offset = timespec64_to_ktime(ns_offsets->boottime);
+		break;
+	default:
+		return tim;
+	}
+
+	/*
+	 * Check that @tim value is in [offset, KTIME_MAX + offset]
+	 * and subtract offset.
+	 */
+	if (tim < offset) {
+		/*
+		 * User can specify @tim *absolute* value - if it's lesser than
+		 * the time namespace's offset - it's already expired.
+		 */
+		tim = 0;
+	} else {
+		tim = ktime_sub(tim, offset);
+		if (unlikely(tim > KTIME_MAX))
+			tim = KTIME_MAX;
+	}
+
+	return tim;
+}
+
+static struct ucounts *inc_time_namespaces(struct user_namespace *ns)
+{
+	return inc_ucount(ns, current_euid(), UCOUNT_TIME_NAMESPACES);
+}
+
+static void dec_time_namespaces(struct ucounts *ucounts)
+{
+	dec_ucount(ucounts, UCOUNT_TIME_NAMESPACES);
+}
+
+/**
+ * clone_time_ns - Clone a time namespace
+ * @user_ns:	User namespace which owns a new namespace.
+ * @old_ns:	Namespace to clone
+ *
+ * Clone @old_ns and set the clone refcount to 1
+ *
+ * Return: The new namespace or ERR_PTR.
+ */
+static struct time_namespace *clone_time_ns(struct user_namespace *user_ns,
+					  struct time_namespace *old_ns)
+{
+	struct time_namespace *ns;
+	struct ucounts *ucounts;
+	int err;
+
+	err = -ENOSPC;
+	ucounts = inc_time_namespaces(user_ns);
+	if (!ucounts)
+		goto fail;
+
+	err = -ENOMEM;
+	ns = kmalloc(sizeof(*ns), GFP_KERNEL_ACCOUNT);
+	if (!ns)
+		goto fail_dec;
+
+	refcount_set(&ns->ns.count, 1);
+
+	ns->vvar_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+	if (!ns->vvar_page)
+		goto fail_free;
+
+	err = ns_alloc_inum(&ns->ns);
+	if (err)
+		goto fail_free_page;
+
+	ns->ucounts = ucounts;
+	ns->ns.ops = &timens_operations;
+	ns->user_ns = get_user_ns(user_ns);
+	ns->offsets = old_ns->offsets;
+	ns->frozen_offsets = false;
+	return ns;
+
+fail_free_page:
+	__free_page(ns->vvar_page);
+fail_free:
+	kfree(ns);
+fail_dec:
+	dec_time_namespaces(ucounts);
+fail:
+	return ERR_PTR(err);
+}
+
+/**
+ * copy_time_ns - Create timens_for_children from @old_ns
+ * @flags:	Cloning flags
+ * @user_ns:	User namespace which owns a new namespace.
+ * @old_ns:	Namespace to clone
+ *
+ * If CLONE_NEWTIME specified in @flags, creates a new timens_for_children;
+ * adds a refcounter to @old_ns otherwise.
+ *
+ * Return: timens_for_children namespace or ERR_PTR.
+ */
+struct time_namespace *copy_time_ns(unsigned long flags,
+	struct user_namespace *user_ns, struct time_namespace *old_ns)
+{
+	if (!(flags & CLONE_NEWTIME))
+		return get_time_ns(old_ns);
+
+	return clone_time_ns(user_ns, old_ns);
+}
+
+static struct timens_offset offset_from_ts(struct timespec64 off)
+{
+	struct timens_offset ret;
+
+	ret.sec = off.tv_sec;
+	ret.nsec = off.tv_nsec;
+
+	return ret;
+}
+
+/*
+ * A time namespace VVAR page has the same layout as the VVAR page which
+ * contains the system wide VDSO data.
+ *
+ * For a normal task the VVAR pages are installed in the normal ordering:
+ *     VVAR
+ *     PVCLOCK
+ *     HVCLOCK
+ *     TIMENS   <- Not really required
+ *
+ * Now for a timens task the pages are installed in the following order:
+ *     TIMENS
+ *     PVCLOCK
+ *     HVCLOCK
+ *     VVAR
+ *
+ * The check for vdso_data->clock_mode is in the unlikely path of
+ * the seq begin magic. So for the non-timens case most of the time
+ * 'seq' is even, so the branch is not taken.
+ *
+ * If 'seq' is odd, i.e. a concurrent update is in progress, the extra check
+ * for vdso_data->clock_mode is a non-issue. The task is spin waiting for the
+ * update to finish and for 'seq' to become even anyway.
+ *
+ * Timens page has vdso_data->clock_mode set to VDSO_CLOCKMODE_TIMENS which
+ * enforces the time namespace handling path.
+ */
+static void timens_setup_vdso_data(struct vdso_data *vdata,
+				   struct time_namespace *ns)
+{
+	struct timens_offset *offset = vdata->offset;
+	struct timens_offset monotonic = offset_from_ts(ns->offsets.monotonic);
+	struct timens_offset boottime = offset_from_ts(ns->offsets.boottime);
+
+	vdata->seq			= 1;
+	vdata->clock_mode		= VDSO_CLOCKMODE_TIMENS;
+	offset[CLOCK_MONOTONIC]		= monotonic;
+	offset[CLOCK_MONOTONIC_RAW]	= monotonic;
+	offset[CLOCK_MONOTONIC_COARSE]	= monotonic;
+	offset[CLOCK_BOOTTIME]		= boottime;
+	offset[CLOCK_BOOTTIME_ALARM]	= boottime;
+}
+
+/*
+ * Protects possibly multiple offsets writers racing each other
+ * and tasks entering the namespace.
+ */
+static DEFINE_MUTEX(offset_lock);
+
+static void timens_set_vvar_page(struct task_struct *task,
+				struct time_namespace *ns)
+{
+	struct vdso_data *vdata;
+	unsigned int i;
+
+	if (ns == &init_time_ns)
+		return;
+
+	/* Fast-path, taken by every task in namespace except the first. */
+	if (likely(ns->frozen_offsets))
+		return;
+
+	mutex_lock(&offset_lock);
+	/* Nothing to-do: vvar_page has been already initialized. */
+	if (ns->frozen_offsets)
+		goto out;
+
+	ns->frozen_offsets = true;
+	vdata = arch_get_vdso_data(page_address(ns->vvar_page));
+
+	for (i = 0; i < CS_BASES; i++)
+		timens_setup_vdso_data(&vdata[i], ns);
+
+out:
+	mutex_unlock(&offset_lock);
+}
+
+void free_time_ns(struct time_namespace *ns)
+{
+	dec_time_namespaces(ns->ucounts);
+	put_user_ns(ns->user_ns);
+	ns_free_inum(&ns->ns);
+	__free_page(ns->vvar_page);
+	kfree(ns);
+}
+
+static struct time_namespace *to_time_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct time_namespace, ns);
+}
+
+static struct ns_common *timens_get(struct task_struct *task)
+{
+	struct time_namespace *ns = NULL;
+	struct nsproxy *nsproxy;
+
+	task_lock(task);
+	nsproxy = task->nsproxy;
+	if (nsproxy) {
+		ns = nsproxy->time_ns;
+		get_time_ns(ns);
+	}
+	task_unlock(task);
+
+	return ns ? &ns->ns : NULL;
+}
+
+static struct ns_common *timens_for_children_get(struct task_struct *task)
+{
+	struct time_namespace *ns = NULL;
+	struct nsproxy *nsproxy;
+
+	task_lock(task);
+	nsproxy = task->nsproxy;
+	if (nsproxy) {
+		ns = nsproxy->time_ns_for_children;
+		get_time_ns(ns);
+	}
+	task_unlock(task);
+
+	return ns ? &ns->ns : NULL;
+}
+
+static void timens_put(struct ns_common *ns)
+{
+	put_time_ns(to_time_ns(ns));
+}
+
+void timens_commit(struct task_struct *tsk, struct time_namespace *ns)
+{
+	timens_set_vvar_page(tsk, ns);
+	vdso_join_timens(tsk, ns);
+}
+
+static int timens_install(struct nsset *nsset, struct ns_common *new)
+{
+	struct nsproxy *nsproxy = nsset->nsproxy;
+	struct time_namespace *ns = to_time_ns(new);
+
+	if (!current_is_single_threaded())
+		return -EUSERS;
+
+	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
+	    !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	get_time_ns(ns);
+	put_time_ns(nsproxy->time_ns);
+	nsproxy->time_ns = ns;
+
+	get_time_ns(ns);
+	put_time_ns(nsproxy->time_ns_for_children);
+	nsproxy->time_ns_for_children = ns;
+	return 0;
+}
+
+void timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk)
+{
+	struct ns_common *nsc = &nsproxy->time_ns_for_children->ns;
+	struct time_namespace *ns = to_time_ns(nsc);
+
+	/* create_new_namespaces() already incremented the ref counter */
+	if (nsproxy->time_ns == nsproxy->time_ns_for_children)
+		return;
+
+	get_time_ns(ns);
+	put_time_ns(nsproxy->time_ns);
+	nsproxy->time_ns = ns;
+
+	timens_commit(tsk, ns);
+}
+
+static struct user_namespace *timens_owner(struct ns_common *ns)
+{
+	return to_time_ns(ns)->user_ns;
+}
+
+static void show_offset(struct seq_file *m, int clockid, struct timespec64 *ts)
+{
+	char *clock;
+
+	switch (clockid) {
+	case CLOCK_BOOTTIME:
+		clock = "boottime";
+		break;
+	case CLOCK_MONOTONIC:
+		clock = "monotonic";
+		break;
+	default:
+		clock = "unknown";
+		break;
+	}
+	seq_printf(m, "%-10s %10lld %9ld\n", clock, ts->tv_sec, ts->tv_nsec);
+}
+
+void proc_timens_show_offsets(struct task_struct *p, struct seq_file *m)
+{
+	struct ns_common *ns;
+	struct time_namespace *time_ns;
+
+	ns = timens_for_children_get(p);
+	if (!ns)
+		return;
+	time_ns = to_time_ns(ns);
+
+	show_offset(m, CLOCK_MONOTONIC, &time_ns->offsets.monotonic);
+	show_offset(m, CLOCK_BOOTTIME, &time_ns->offsets.boottime);
+	put_time_ns(time_ns);
+}
+
+int proc_timens_set_offset(struct file *file, struct task_struct *p,
+			   struct proc_timens_offset *offsets, int noffsets)
+{
+	struct ns_common *ns;
+	struct time_namespace *time_ns;
+	struct timespec64 tp;
+	int i, err;
+
+	ns = timens_for_children_get(p);
+	if (!ns)
+		return -ESRCH;
+	time_ns = to_time_ns(ns);
+
+	if (!file_ns_capable(file, time_ns->user_ns, CAP_SYS_TIME)) {
+		put_time_ns(time_ns);
+		return -EPERM;
+	}
+
+	for (i = 0; i < noffsets; i++) {
+		struct proc_timens_offset *off = &offsets[i];
+
+		switch (off->clockid) {
+		case CLOCK_MONOTONIC:
+			ktime_get_ts64(&tp);
+			break;
+		case CLOCK_BOOTTIME:
+			ktime_get_boottime_ts64(&tp);
+			break;
+		default:
+			err = -EINVAL;
+			goto out;
+		}
+
+		err = -ERANGE;
+
+		if (off->val.tv_sec > KTIME_SEC_MAX ||
+		    off->val.tv_sec < -KTIME_SEC_MAX)
+			goto out;
+
+		tp = timespec64_add(tp, off->val);
+		/*
+		 * KTIME_SEC_MAX is divided by 2 to be sure that KTIME_MAX is
+		 * still unreachable.
+		 */
+		if (tp.tv_sec < 0 || tp.tv_sec > KTIME_SEC_MAX / 2)
+			goto out;
+	}
+
+	mutex_lock(&offset_lock);
+	if (time_ns->frozen_offsets) {
+		err = -EACCES;
+		goto out_unlock;
+	}
+
+	err = 0;
+	/* Don't report errors after this line */
+	for (i = 0; i < noffsets; i++) {
+		struct proc_timens_offset *off = &offsets[i];
+		struct timespec64 *offset = NULL;
+
+		switch (off->clockid) {
+		case CLOCK_MONOTONIC:
+			offset = &time_ns->offsets.monotonic;
+			break;
+		case CLOCK_BOOTTIME:
+			offset = &time_ns->offsets.boottime;
+			break;
+		}
+
+		*offset = off->val;
+	}
+
+out_unlock:
+	mutex_unlock(&offset_lock);
+out:
+	put_time_ns(time_ns);
+
+	return err;
+}
+
+const struct proc_ns_operations timens_operations = {
+	.name		= "time",
+	.type		= CLONE_NEWTIME,
+	.get		= timens_get,
+	.put		= timens_put,
+	.install	= timens_install,
+	.owner		= timens_owner,
+};
+
+const struct proc_ns_operations timens_for_children_operations = {
+	.name		= "time_for_children",
+	.real_ns_name	= "time",
+	.type		= CLONE_NEWTIME,
+	.get		= timens_for_children_get,
+	.put		= timens_put,
+	.install	= timens_install,
+	.owner		= timens_owner,
+};
+
+struct time_namespace init_time_ns = {
+	.ns.count	= REFCOUNT_INIT(3),
+	.user_ns	= &init_user_ns,
+	.ns.inum	= PROC_TIME_INIT_INO,
+	.ns.ops		= &timens_operations,
+	.frozen_offsets	= true,
+};
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
new file mode 100644
index 000000000..406dccb79
--- /dev/null
+++ b/kernel/time/ntp.c
@@ -0,0 +1,1096 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NTP state machine interfaces and logic.
+ *
+ * This code was mainly moved from kernel/timer.c and kernel/time.c
+ * Please see those files for relevant copyright info and historical
+ * changelogs.
+ */
+#include <linux/capability.h>
+#include <linux/clocksource.h>
+#include <linux/workqueue.h>
+#include <linux/hrtimer.h>
+#include <linux/jiffies.h>
+#include <linux/math64.h>
+#include <linux/timex.h>
+#include <linux/time.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/audit.h>
+
+#include "ntp_internal.h"
+#include "timekeeping_internal.h"
+
+
+/*
+ * NTP timekeeping variables:
+ *
+ * Note: All of the NTP state is protected by the timekeeping locks.
+ */
+
+
+/* USER_HZ period (usecs): */
+unsigned long			tick_usec = USER_TICK_USEC;
+
+/* SHIFTED_HZ period (nsecs): */
+unsigned long			tick_nsec;
+
+static u64			tick_length;
+static u64			tick_length_base;
+
+#define SECS_PER_DAY		86400
+#define MAX_TICKADJ		500LL		/* usecs */
+#define MAX_TICKADJ_SCALED \
+	(((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
+#define MAX_TAI_OFFSET		100000
+
+/*
+ * phase-lock loop variables
+ */
+
+/*
+ * clock synchronization status
+ *
+ * (TIME_ERROR prevents overwriting the CMOS clock)
+ */
+static int			time_state = TIME_OK;
+
+/* clock status bits:							*/
+static int			time_status = STA_UNSYNC;
+
+/* time adjustment (nsecs):						*/
+static s64			time_offset;
+
+/* pll time constant:							*/
+static long			time_constant = 2;
+
+/* maximum error (usecs):						*/
+static long			time_maxerror = NTP_PHASE_LIMIT;
+
+/* estimated error (usecs):						*/
+static long			time_esterror = NTP_PHASE_LIMIT;
+
+/* frequency offset (scaled nsecs/secs):				*/
+static s64			time_freq;
+
+/* time at last adjustment (secs):					*/
+static time64_t		time_reftime;
+
+static long			time_adjust;
+
+/* constant (boot-param configurable) NTP tick adjustment (upscaled)	*/
+static s64			ntp_tick_adj;
+
+/* second value of the next pending leapsecond, or TIME64_MAX if no leap */
+static time64_t			ntp_next_leap_sec = TIME64_MAX;
+
+#ifdef CONFIG_NTP_PPS
+
+/*
+ * The following variables are used when a pulse-per-second (PPS) signal
+ * is available. They establish the engineering parameters of the clock
+ * discipline loop when controlled by the PPS signal.
+ */
+#define PPS_VALID	10	/* PPS signal watchdog max (s) */
+#define PPS_POPCORN	4	/* popcorn spike threshold (shift) */
+#define PPS_INTMIN	2	/* min freq interval (s) (shift) */
+#define PPS_INTMAX	8	/* max freq interval (s) (shift) */
+#define PPS_INTCOUNT	4	/* number of consecutive good intervals to
+				   increase pps_shift or consecutive bad
+				   intervals to decrease it */
+#define PPS_MAXWANDER	100000	/* max PPS freq wander (ns/s) */
+
+static int pps_valid;		/* signal watchdog counter */
+static long pps_tf[3];		/* phase median filter */
+static long pps_jitter;		/* current jitter (ns) */
+static struct timespec64 pps_fbase; /* beginning of the last freq interval */
+static int pps_shift;		/* current interval duration (s) (shift) */
+static int pps_intcnt;		/* interval counter */
+static s64 pps_freq;		/* frequency offset (scaled ns/s) */
+static long pps_stabil;		/* current stability (scaled ns/s) */
+
+/*
+ * PPS signal quality monitors
+ */
+static long pps_calcnt;		/* calibration intervals */
+static long pps_jitcnt;		/* jitter limit exceeded */
+static long pps_stbcnt;		/* stability limit exceeded */
+static long pps_errcnt;		/* calibration errors */
+
+
+/* PPS kernel consumer compensates the whole phase error immediately.
+ * Otherwise, reduce the offset by a fixed factor times the time constant.
+ */
+static inline s64 ntp_offset_chunk(s64 offset)
+{
+	if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL)
+		return offset;
+	else
+		return shift_right(offset, SHIFT_PLL + time_constant);
+}
+
+static inline void pps_reset_freq_interval(void)
+{
+	/* the PPS calibration interval may end
+	   surprisingly early */
+	pps_shift = PPS_INTMIN;
+	pps_intcnt = 0;
+}
+
+/**
+ * pps_clear - Clears the PPS state variables
+ */
+static inline void pps_clear(void)
+{
+	pps_reset_freq_interval();
+	pps_tf[0] = 0;
+	pps_tf[1] = 0;
+	pps_tf[2] = 0;
+	pps_fbase.tv_sec = pps_fbase.tv_nsec = 0;
+	pps_freq = 0;
+}
+
+/* Decrease pps_valid to indicate that another second has passed since
+ * the last PPS signal. When it reaches 0, indicate that PPS signal is
+ * missing.
+ */
+static inline void pps_dec_valid(void)
+{
+	if (pps_valid > 0)
+		pps_valid--;
+	else {
+		time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
+				 STA_PPSWANDER | STA_PPSERROR);
+		pps_clear();
+	}
+}
+
+static inline void pps_set_freq(s64 freq)
+{
+	pps_freq = freq;
+}
+
+static inline int is_error_status(int status)
+{
+	return (status & (STA_UNSYNC|STA_CLOCKERR))
+		/* PPS signal lost when either PPS time or
+		 * PPS frequency synchronization requested
+		 */
+		|| ((status & (STA_PPSFREQ|STA_PPSTIME))
+			&& !(status & STA_PPSSIGNAL))
+		/* PPS jitter exceeded when
+		 * PPS time synchronization requested */
+		|| ((status & (STA_PPSTIME|STA_PPSJITTER))
+			== (STA_PPSTIME|STA_PPSJITTER))
+		/* PPS wander exceeded or calibration error when
+		 * PPS frequency synchronization requested
+		 */
+		|| ((status & STA_PPSFREQ)
+			&& (status & (STA_PPSWANDER|STA_PPSERROR)));
+}
+
+static inline void pps_fill_timex(struct __kernel_timex *txc)
+{
+	txc->ppsfreq	   = shift_right((pps_freq >> PPM_SCALE_INV_SHIFT) *
+					 PPM_SCALE_INV, NTP_SCALE_SHIFT);
+	txc->jitter	   = pps_jitter;
+	if (!(time_status & STA_NANO))
+		txc->jitter = pps_jitter / NSEC_PER_USEC;
+	txc->shift	   = pps_shift;
+	txc->stabil	   = pps_stabil;
+	txc->jitcnt	   = pps_jitcnt;
+	txc->calcnt	   = pps_calcnt;
+	txc->errcnt	   = pps_errcnt;
+	txc->stbcnt	   = pps_stbcnt;
+}
+
+#else /* !CONFIG_NTP_PPS */
+
+static inline s64 ntp_offset_chunk(s64 offset)
+{
+	return shift_right(offset, SHIFT_PLL + time_constant);
+}
+
+static inline void pps_reset_freq_interval(void) {}
+static inline void pps_clear(void) {}
+static inline void pps_dec_valid(void) {}
+static inline void pps_set_freq(s64 freq) {}
+
+static inline int is_error_status(int status)
+{
+	return status & (STA_UNSYNC|STA_CLOCKERR);
+}
+
+static inline void pps_fill_timex(struct __kernel_timex *txc)
+{
+	/* PPS is not implemented, so these are zero */
+	txc->ppsfreq	   = 0;
+	txc->jitter	   = 0;
+	txc->shift	   = 0;
+	txc->stabil	   = 0;
+	txc->jitcnt	   = 0;
+	txc->calcnt	   = 0;
+	txc->errcnt	   = 0;
+	txc->stbcnt	   = 0;
+}
+
+#endif /* CONFIG_NTP_PPS */
+
+
+/**
+ * ntp_synced - Returns 1 if the NTP status is not UNSYNC
+ *
+ */
+static inline int ntp_synced(void)
+{
+	return !(time_status & STA_UNSYNC);
+}
+
+
+/*
+ * NTP methods:
+ */
+
+/*
+ * Update (tick_length, tick_length_base, tick_nsec), based
+ * on (tick_usec, ntp_tick_adj, time_freq):
+ */
+static void ntp_update_frequency(void)
+{
+	u64 second_length;
+	u64 new_base;
+
+	second_length		 = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
+						<< NTP_SCALE_SHIFT;
+
+	second_length		+= ntp_tick_adj;
+	second_length		+= time_freq;
+
+	tick_nsec		 = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT;
+	new_base		 = div_u64(second_length, NTP_INTERVAL_FREQ);
+
+	/*
+	 * Don't wait for the next second_overflow, apply
+	 * the change to the tick length immediately:
+	 */
+	tick_length		+= new_base - tick_length_base;
+	tick_length_base	 = new_base;
+}
+
+static inline s64 ntp_update_offset_fll(s64 offset64, long secs)
+{
+	time_status &= ~STA_MODE;
+
+	if (secs < MINSEC)
+		return 0;
+
+	if (!(time_status & STA_FLL) && (secs <= MAXSEC))
+		return 0;
+
+	time_status |= STA_MODE;
+
+	return div64_long(offset64 << (NTP_SCALE_SHIFT - SHIFT_FLL), secs);
+}
+
+static void ntp_update_offset(long offset)
+{
+	s64 freq_adj;
+	s64 offset64;
+	long secs;
+
+	if (!(time_status & STA_PLL))
+		return;
+
+	if (!(time_status & STA_NANO)) {
+		/* Make sure the multiplication below won't overflow */
+		offset = clamp(offset, -USEC_PER_SEC, USEC_PER_SEC);
+		offset *= NSEC_PER_USEC;
+	}
+
+	/*
+	 * Scale the phase adjustment and
+	 * clamp to the operating range.
+	 */
+	offset = clamp(offset, -MAXPHASE, MAXPHASE);
+
+	/*
+	 * Select how the frequency is to be controlled
+	 * and in which mode (PLL or FLL).
+	 */
+	secs = (long)(__ktime_get_real_seconds() - time_reftime);
+	if (unlikely(time_status & STA_FREQHOLD))
+		secs = 0;
+
+	time_reftime = __ktime_get_real_seconds();
+
+	offset64    = offset;
+	freq_adj    = ntp_update_offset_fll(offset64, secs);
+
+	/*
+	 * Clamp update interval to reduce PLL gain with low
+	 * sampling rate (e.g. intermittent network connection)
+	 * to avoid instability.
+	 */
+	if (unlikely(secs > 1 << (SHIFT_PLL + 1 + time_constant)))
+		secs = 1 << (SHIFT_PLL + 1 + time_constant);
+
+	freq_adj    += (offset64 * secs) <<
+			(NTP_SCALE_SHIFT - 2 * (SHIFT_PLL + 2 + time_constant));
+
+	freq_adj    = min(freq_adj + time_freq, MAXFREQ_SCALED);
+
+	time_freq   = max(freq_adj, -MAXFREQ_SCALED);
+
+	time_offset = div_s64(offset64 << NTP_SCALE_SHIFT, NTP_INTERVAL_FREQ);
+}
+
+/**
+ * ntp_clear - Clears the NTP state variables
+ */
+void ntp_clear(void)
+{
+	time_adjust	= 0;		/* stop active adjtime() */
+	time_status	|= STA_UNSYNC;
+	time_maxerror	= NTP_PHASE_LIMIT;
+	time_esterror	= NTP_PHASE_LIMIT;
+
+	ntp_update_frequency();
+
+	tick_length	= tick_length_base;
+	time_offset	= 0;
+
+	ntp_next_leap_sec = TIME64_MAX;
+	/* Clear PPS state variables */
+	pps_clear();
+}
+
+
+u64 ntp_tick_length(void)
+{
+	return tick_length;
+}
+
+/**
+ * ntp_get_next_leap - Returns the next leapsecond in CLOCK_REALTIME ktime_t
+ *
+ * Provides the time of the next leapsecond against CLOCK_REALTIME in
+ * a ktime_t format. Returns KTIME_MAX if no leapsecond is pending.
+ */
+ktime_t ntp_get_next_leap(void)
+{
+	ktime_t ret;
+
+	if ((time_state == TIME_INS) && (time_status & STA_INS))
+		return ktime_set(ntp_next_leap_sec, 0);
+	ret = KTIME_MAX;
+	return ret;
+}
+
+/*
+ * this routine handles the overflow of the microsecond field
+ *
+ * The tricky bits of code to handle the accurate clock support
+ * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
+ * They were originally developed for SUN and DEC kernels.
+ * All the kudos should go to Dave for this stuff.
+ *
+ * Also handles leap second processing, and returns leap offset
+ */
+int second_overflow(time64_t secs)
+{
+	s64 delta;
+	int leap = 0;
+	s32 rem;
+
+	/*
+	 * Leap second processing. If in leap-insert state at the end of the
+	 * day, the system clock is set back one second; if in leap-delete
+	 * state, the system clock is set ahead one second.
+	 */
+	switch (time_state) {
+	case TIME_OK:
+		if (time_status & STA_INS) {
+			time_state = TIME_INS;
+			div_s64_rem(secs, SECS_PER_DAY, &rem);
+			ntp_next_leap_sec = secs + SECS_PER_DAY - rem;
+		} else if (time_status & STA_DEL) {
+			time_state = TIME_DEL;
+			div_s64_rem(secs + 1, SECS_PER_DAY, &rem);
+			ntp_next_leap_sec = secs + SECS_PER_DAY - rem;
+		}
+		break;
+	case TIME_INS:
+		if (!(time_status & STA_INS)) {
+			ntp_next_leap_sec = TIME64_MAX;
+			time_state = TIME_OK;
+		} else if (secs == ntp_next_leap_sec) {
+			leap = -1;
+			time_state = TIME_OOP;
+			printk(KERN_NOTICE
+				"Clock: inserting leap second 23:59:60 UTC\n");
+		}
+		break;
+	case TIME_DEL:
+		if (!(time_status & STA_DEL)) {
+			ntp_next_leap_sec = TIME64_MAX;
+			time_state = TIME_OK;
+		} else if (secs == ntp_next_leap_sec) {
+			leap = 1;
+			ntp_next_leap_sec = TIME64_MAX;
+			time_state = TIME_WAIT;
+			printk(KERN_NOTICE
+				"Clock: deleting leap second 23:59:59 UTC\n");
+		}
+		break;
+	case TIME_OOP:
+		ntp_next_leap_sec = TIME64_MAX;
+		time_state = TIME_WAIT;
+		break;
+	case TIME_WAIT:
+		if (!(time_status & (STA_INS | STA_DEL)))
+			time_state = TIME_OK;
+		break;
+	}
+
+
+	/* Bump the maxerror field */
+	time_maxerror += MAXFREQ / NSEC_PER_USEC;
+	if (time_maxerror > NTP_PHASE_LIMIT) {
+		time_maxerror = NTP_PHASE_LIMIT;
+		time_status |= STA_UNSYNC;
+	}
+
+	/* Compute the phase adjustment for the next second */
+	tick_length	 = tick_length_base;
+
+	delta		 = ntp_offset_chunk(time_offset);
+	time_offset	-= delta;
+	tick_length	+= delta;
+
+	/* Check PPS signal */
+	pps_dec_valid();
+
+	if (!time_adjust)
+		goto out;
+
+	if (time_adjust > MAX_TICKADJ) {
+		time_adjust -= MAX_TICKADJ;
+		tick_length += MAX_TICKADJ_SCALED;
+		goto out;
+	}
+
+	if (time_adjust < -MAX_TICKADJ) {
+		time_adjust += MAX_TICKADJ;
+		tick_length -= MAX_TICKADJ_SCALED;
+		goto out;
+	}
+
+	tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ)
+							 << NTP_SCALE_SHIFT;
+	time_adjust = 0;
+
+out:
+	return leap;
+}
+
+#if defined(CONFIG_GENERIC_CMOS_UPDATE) || defined(CONFIG_RTC_SYSTOHC)
+static void sync_hw_clock(struct work_struct *work);
+static DECLARE_WORK(sync_work, sync_hw_clock);
+static struct hrtimer sync_hrtimer;
+#define SYNC_PERIOD_NS (11ULL * 60 * NSEC_PER_SEC)
+
+static enum hrtimer_restart sync_timer_callback(struct hrtimer *timer)
+{
+	queue_work(system_freezable_power_efficient_wq, &sync_work);
+
+	return HRTIMER_NORESTART;
+}
+
+static void sched_sync_hw_clock(unsigned long offset_nsec, bool retry)
+{
+	ktime_t exp = ktime_set(ktime_get_real_seconds(), 0);
+
+	if (retry)
+		exp = ktime_add_ns(exp, 2ULL * NSEC_PER_SEC - offset_nsec);
+	else
+		exp = ktime_add_ns(exp, SYNC_PERIOD_NS - offset_nsec);
+
+	hrtimer_start(&sync_hrtimer, exp, HRTIMER_MODE_ABS);
+}
+
+/*
+ * Check whether @now is correct versus the required time to update the RTC
+ * and calculate the value which needs to be written to the RTC so that the
+ * next seconds increment of the RTC after the write is aligned with the next
+ * seconds increment of clock REALTIME.
+ *
+ * tsched     t1 write(t2.tv_sec - 1sec))	t2 RTC increments seconds
+ *
+ * t2.tv_nsec == 0
+ * tsched = t2 - set_offset_nsec
+ * newval = t2 - NSEC_PER_SEC
+ *
+ * ==> neval = tsched + set_offset_nsec - NSEC_PER_SEC
+ *
+ * As the execution of this code is not guaranteed to happen exactly at
+ * tsched this allows it to happen within a fuzzy region:
+ *
+ *	abs(now - tsched) < FUZZ
+ *
+ * If @now is not inside the allowed window the function returns false.
+ */
+static inline bool rtc_tv_nsec_ok(unsigned long set_offset_nsec,
+				  struct timespec64 *to_set,
+				  const struct timespec64 *now)
+{
+	/* Allowed error in tv_nsec, arbitrarily set to 5 jiffies in ns. */
+	const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
+	struct timespec64 delay = {.tv_sec = -1,
+				   .tv_nsec = set_offset_nsec};
+
+	*to_set = timespec64_add(*now, delay);
+
+	if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
+		to_set->tv_nsec = 0;
+		return true;
+	}
+
+	if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
+		to_set->tv_sec++;
+		to_set->tv_nsec = 0;
+		return true;
+	}
+	return false;
+}
+
+#ifdef CONFIG_GENERIC_CMOS_UPDATE
+int __weak update_persistent_clock64(struct timespec64 now64)
+{
+	return -ENODEV;
+}
+#else
+static inline int update_persistent_clock64(struct timespec64 now64)
+{
+	return -ENODEV;
+}
+#endif
+
+#ifdef CONFIG_RTC_SYSTOHC
+/* Save NTP synchronized time to the RTC */
+static int update_rtc(struct timespec64 *to_set, unsigned long *offset_nsec)
+{
+	struct rtc_device *rtc;
+	struct rtc_time tm;
+	int err = -ENODEV;
+
+	rtc = rtc_class_open(CONFIG_RTC_SYSTOHC_DEVICE);
+	if (!rtc)
+		return -ENODEV;
+
+	if (!rtc->ops || !rtc->ops->set_time)
+		goto out_close;
+
+	/* First call might not have the correct offset */
+	if (*offset_nsec == rtc->set_offset_nsec) {
+		rtc_time64_to_tm(to_set->tv_sec, &tm);
+		err = rtc_set_time(rtc, &tm);
+	} else {
+		/* Store the update offset and let the caller try again */
+		*offset_nsec = rtc->set_offset_nsec;
+		err = -EAGAIN;
+	}
+out_close:
+	rtc_class_close(rtc);
+	return err;
+}
+#else
+static inline int update_rtc(struct timespec64 *to_set, unsigned long *offset_nsec)
+{
+	return -ENODEV;
+}
+#endif
+
+/*
+ * If we have an externally synchronized Linux clock, then update RTC clock
+ * accordingly every ~11 minutes. Generally RTCs can only store second
+ * precision, but many RTCs will adjust the phase of their second tick to
+ * match the moment of update. This infrastructure arranges to call to the RTC
+ * set at the correct moment to phase synchronize the RTC second tick over
+ * with the kernel clock.
+ */
+static void sync_hw_clock(struct work_struct *work)
+{
+	/*
+	 * The default synchronization offset is 500ms for the deprecated
+	 * update_persistent_clock64() under the assumption that it uses
+	 * the infamous CMOS clock (MC146818).
+	 */
+	static unsigned long offset_nsec = NSEC_PER_SEC / 2;
+	struct timespec64 now, to_set;
+	int res = -EAGAIN;
+
+	/*
+	 * Don't update if STA_UNSYNC is set and if ntp_notify_cmos_timer()
+	 * managed to schedule the work between the timer firing and the
+	 * work being able to rearm the timer. Wait for the timer to expire.
+	 */
+	if (!ntp_synced() || hrtimer_is_queued(&sync_hrtimer))
+		return;
+
+	ktime_get_real_ts64(&now);
+	/* If @now is not in the allowed window, try again */
+	if (!rtc_tv_nsec_ok(offset_nsec, &to_set, &now))
+		goto rearm;
+
+	/* Take timezone adjusted RTCs into account */
+	if (persistent_clock_is_local)
+		to_set.tv_sec -= (sys_tz.tz_minuteswest * 60);
+
+	/* Try the legacy RTC first. */
+	res = update_persistent_clock64(to_set);
+	if (res != -ENODEV)
+		goto rearm;
+
+	/* Try the RTC class */
+	res = update_rtc(&to_set, &offset_nsec);
+	if (res == -ENODEV)
+		return;
+rearm:
+	sched_sync_hw_clock(offset_nsec, res != 0);
+}
+
+void ntp_notify_cmos_timer(void)
+{
+	/*
+	 * When the work is currently executed but has not yet the timer
+	 * rearmed this queues the work immediately again. No big issue,
+	 * just a pointless work scheduled.
+	 */
+	if (ntp_synced() && !hrtimer_is_queued(&sync_hrtimer))
+		queue_work(system_freezable_power_efficient_wq, &sync_work);
+}
+
+static void __init ntp_init_cmos_sync(void)
+{
+	hrtimer_init(&sync_hrtimer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
+	sync_hrtimer.function = sync_timer_callback;
+}
+#else /* CONFIG_GENERIC_CMOS_UPDATE) || defined(CONFIG_RTC_SYSTOHC) */
+static inline void __init ntp_init_cmos_sync(void) { }
+#endif /* !CONFIG_GENERIC_CMOS_UPDATE) || defined(CONFIG_RTC_SYSTOHC) */
+
+/*
+ * Propagate a new txc->status value into the NTP state:
+ */
+static inline void process_adj_status(const struct __kernel_timex *txc)
+{
+	if ((time_status & STA_PLL) && !(txc->status & STA_PLL)) {
+		time_state = TIME_OK;
+		time_status = STA_UNSYNC;
+		ntp_next_leap_sec = TIME64_MAX;
+		/* restart PPS frequency calibration */
+		pps_reset_freq_interval();
+	}
+
+	/*
+	 * If we turn on PLL adjustments then reset the
+	 * reference time to current time.
+	 */
+	if (!(time_status & STA_PLL) && (txc->status & STA_PLL))
+		time_reftime = __ktime_get_real_seconds();
+
+	/* only set allowed bits */
+	time_status &= STA_RONLY;
+	time_status |= txc->status & ~STA_RONLY;
+}
+
+
+static inline void process_adjtimex_modes(const struct __kernel_timex *txc,
+					  s32 *time_tai)
+{
+	if (txc->modes & ADJ_STATUS)
+		process_adj_status(txc);
+
+	if (txc->modes & ADJ_NANO)
+		time_status |= STA_NANO;
+
+	if (txc->modes & ADJ_MICRO)
+		time_status &= ~STA_NANO;
+
+	if (txc->modes & ADJ_FREQUENCY) {
+		time_freq = txc->freq * PPM_SCALE;
+		time_freq = min(time_freq, MAXFREQ_SCALED);
+		time_freq = max(time_freq, -MAXFREQ_SCALED);
+		/* update pps_freq */
+		pps_set_freq(time_freq);
+	}
+
+	if (txc->modes & ADJ_MAXERROR)
+		time_maxerror = txc->maxerror;
+
+	if (txc->modes & ADJ_ESTERROR)
+		time_esterror = txc->esterror;
+
+	if (txc->modes & ADJ_TIMECONST) {
+		time_constant = txc->constant;
+		if (!(time_status & STA_NANO))
+			time_constant += 4;
+		time_constant = min(time_constant, (long)MAXTC);
+		time_constant = max(time_constant, 0l);
+	}
+
+	if (txc->modes & ADJ_TAI &&
+			txc->constant >= 0 && txc->constant <= MAX_TAI_OFFSET)
+		*time_tai = txc->constant;
+
+	if (txc->modes & ADJ_OFFSET)
+		ntp_update_offset(txc->offset);
+
+	if (txc->modes & ADJ_TICK)
+		tick_usec = txc->tick;
+
+	if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
+		ntp_update_frequency();
+}
+
+
+/*
+ * adjtimex mainly allows reading (and writing, if superuser) of
+ * kernel time-keeping variables. used by xntpd.
+ */
+int __do_adjtimex(struct __kernel_timex *txc, const struct timespec64 *ts,
+		  s32 *time_tai, struct audit_ntp_data *ad)
+{
+	int result;
+
+	if (txc->modes & ADJ_ADJTIME) {
+		long save_adjust = time_adjust;
+
+		if (!(txc->modes & ADJ_OFFSET_READONLY)) {
+			/* adjtime() is independent from ntp_adjtime() */
+			time_adjust = txc->offset;
+			ntp_update_frequency();
+
+			audit_ntp_set_old(ad, AUDIT_NTP_ADJUST,	save_adjust);
+			audit_ntp_set_new(ad, AUDIT_NTP_ADJUST,	time_adjust);
+		}
+		txc->offset = save_adjust;
+	} else {
+		/* If there are input parameters, then process them: */
+		if (txc->modes) {
+			audit_ntp_set_old(ad, AUDIT_NTP_OFFSET,	time_offset);
+			audit_ntp_set_old(ad, AUDIT_NTP_FREQ,	time_freq);
+			audit_ntp_set_old(ad, AUDIT_NTP_STATUS,	time_status);
+			audit_ntp_set_old(ad, AUDIT_NTP_TAI,	*time_tai);
+			audit_ntp_set_old(ad, AUDIT_NTP_TICK,	tick_usec);
+
+			process_adjtimex_modes(txc, time_tai);
+
+			audit_ntp_set_new(ad, AUDIT_NTP_OFFSET,	time_offset);
+			audit_ntp_set_new(ad, AUDIT_NTP_FREQ,	time_freq);
+			audit_ntp_set_new(ad, AUDIT_NTP_STATUS,	time_status);
+			audit_ntp_set_new(ad, AUDIT_NTP_TAI,	*time_tai);
+			audit_ntp_set_new(ad, AUDIT_NTP_TICK,	tick_usec);
+		}
+
+		txc->offset = shift_right(time_offset * NTP_INTERVAL_FREQ,
+				  NTP_SCALE_SHIFT);
+		if (!(time_status & STA_NANO))
+			txc->offset = (u32)txc->offset / NSEC_PER_USEC;
+	}
+
+	result = time_state;	/* mostly `TIME_OK' */
+	/* check for errors */
+	if (is_error_status(time_status))
+		result = TIME_ERROR;
+
+	txc->freq	   = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) *
+					 PPM_SCALE_INV, NTP_SCALE_SHIFT);
+	txc->maxerror	   = time_maxerror;
+	txc->esterror	   = time_esterror;
+	txc->status	   = time_status;
+	txc->constant	   = time_constant;
+	txc->precision	   = 1;
+	txc->tolerance	   = MAXFREQ_SCALED / PPM_SCALE;
+	txc->tick	   = tick_usec;
+	txc->tai	   = *time_tai;
+
+	/* fill PPS status fields */
+	pps_fill_timex(txc);
+
+	txc->time.tv_sec = ts->tv_sec;
+	txc->time.tv_usec = ts->tv_nsec;
+	if (!(time_status & STA_NANO))
+		txc->time.tv_usec = ts->tv_nsec / NSEC_PER_USEC;
+
+	/* Handle leapsec adjustments */
+	if (unlikely(ts->tv_sec >= ntp_next_leap_sec)) {
+		if ((time_state == TIME_INS) && (time_status & STA_INS)) {
+			result = TIME_OOP;
+			txc->tai++;
+			txc->time.tv_sec--;
+		}
+		if ((time_state == TIME_DEL) && (time_status & STA_DEL)) {
+			result = TIME_WAIT;
+			txc->tai--;
+			txc->time.tv_sec++;
+		}
+		if ((time_state == TIME_OOP) &&
+					(ts->tv_sec == ntp_next_leap_sec)) {
+			result = TIME_WAIT;
+		}
+	}
+
+	return result;
+}
+
+#ifdef	CONFIG_NTP_PPS
+
+/* actually struct pps_normtime is good old struct timespec, but it is
+ * semantically different (and it is the reason why it was invented):
+ * pps_normtime.nsec has a range of ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ]
+ * while timespec.tv_nsec has a range of [0, NSEC_PER_SEC) */
+struct pps_normtime {
+	s64		sec;	/* seconds */
+	long		nsec;	/* nanoseconds */
+};
+
+/* normalize the timestamp so that nsec is in the
+   ( -NSEC_PER_SEC / 2, NSEC_PER_SEC / 2 ] interval */
+static inline struct pps_normtime pps_normalize_ts(struct timespec64 ts)
+{
+	struct pps_normtime norm = {
+		.sec = ts.tv_sec,
+		.nsec = ts.tv_nsec
+	};
+
+	if (norm.nsec > (NSEC_PER_SEC >> 1)) {
+		norm.nsec -= NSEC_PER_SEC;
+		norm.sec++;
+	}
+
+	return norm;
+}
+
+/* get current phase correction and jitter */
+static inline long pps_phase_filter_get(long *jitter)
+{
+	*jitter = pps_tf[0] - pps_tf[1];
+	if (*jitter < 0)
+		*jitter = -*jitter;
+
+	/* TODO: test various filters */
+	return pps_tf[0];
+}
+
+/* add the sample to the phase filter */
+static inline void pps_phase_filter_add(long err)
+{
+	pps_tf[2] = pps_tf[1];
+	pps_tf[1] = pps_tf[0];
+	pps_tf[0] = err;
+}
+
+/* decrease frequency calibration interval length.
+ * It is halved after four consecutive unstable intervals.
+ */
+static inline void pps_dec_freq_interval(void)
+{
+	if (--pps_intcnt <= -PPS_INTCOUNT) {
+		pps_intcnt = -PPS_INTCOUNT;
+		if (pps_shift > PPS_INTMIN) {
+			pps_shift--;
+			pps_intcnt = 0;
+		}
+	}
+}
+
+/* increase frequency calibration interval length.
+ * It is doubled after four consecutive stable intervals.
+ */
+static inline void pps_inc_freq_interval(void)
+{
+	if (++pps_intcnt >= PPS_INTCOUNT) {
+		pps_intcnt = PPS_INTCOUNT;
+		if (pps_shift < PPS_INTMAX) {
+			pps_shift++;
+			pps_intcnt = 0;
+		}
+	}
+}
+
+/* update clock frequency based on MONOTONIC_RAW clock PPS signal
+ * timestamps
+ *
+ * At the end of the calibration interval the difference between the
+ * first and last MONOTONIC_RAW clock timestamps divided by the length
+ * of the interval becomes the frequency update. If the interval was
+ * too long, the data are discarded.
+ * Returns the difference between old and new frequency values.
+ */
+static long hardpps_update_freq(struct pps_normtime freq_norm)
+{
+	long delta, delta_mod;
+	s64 ftemp;
+
+	/* check if the frequency interval was too long */
+	if (freq_norm.sec > (2 << pps_shift)) {
+		time_status |= STA_PPSERROR;
+		pps_errcnt++;
+		pps_dec_freq_interval();
+		printk_deferred(KERN_ERR
+			"hardpps: PPSERROR: interval too long - %lld s\n",
+			freq_norm.sec);
+		return 0;
+	}
+
+	/* here the raw frequency offset and wander (stability) is
+	 * calculated. If the wander is less than the wander threshold
+	 * the interval is increased; otherwise it is decreased.
+	 */
+	ftemp = div_s64(((s64)(-freq_norm.nsec)) << NTP_SCALE_SHIFT,
+			freq_norm.sec);
+	delta = shift_right(ftemp - pps_freq, NTP_SCALE_SHIFT);
+	pps_freq = ftemp;
+	if (delta > PPS_MAXWANDER || delta < -PPS_MAXWANDER) {
+		printk_deferred(KERN_WARNING
+				"hardpps: PPSWANDER: change=%ld\n", delta);
+		time_status |= STA_PPSWANDER;
+		pps_stbcnt++;
+		pps_dec_freq_interval();
+	} else {	/* good sample */
+		pps_inc_freq_interval();
+	}
+
+	/* the stability metric is calculated as the average of recent
+	 * frequency changes, but is used only for performance
+	 * monitoring
+	 */
+	delta_mod = delta;
+	if (delta_mod < 0)
+		delta_mod = -delta_mod;
+	pps_stabil += (div_s64(((s64)delta_mod) <<
+				(NTP_SCALE_SHIFT - SHIFT_USEC),
+				NSEC_PER_USEC) - pps_stabil) >> PPS_INTMIN;
+
+	/* if enabled, the system clock frequency is updated */
+	if ((time_status & STA_PPSFREQ) != 0 &&
+	    (time_status & STA_FREQHOLD) == 0) {
+		time_freq = pps_freq;
+		ntp_update_frequency();
+	}
+
+	return delta;
+}
+
+/* correct REALTIME clock phase error against PPS signal */
+static void hardpps_update_phase(long error)
+{
+	long correction = -error;
+	long jitter;
+
+	/* add the sample to the median filter */
+	pps_phase_filter_add(correction);
+	correction = pps_phase_filter_get(&jitter);
+
+	/* Nominal jitter is due to PPS signal noise. If it exceeds the
+	 * threshold, the sample is discarded; otherwise, if so enabled,
+	 * the time offset is updated.
+	 */
+	if (jitter > (pps_jitter << PPS_POPCORN)) {
+		printk_deferred(KERN_WARNING
+				"hardpps: PPSJITTER: jitter=%ld, limit=%ld\n",
+				jitter, (pps_jitter << PPS_POPCORN));
+		time_status |= STA_PPSJITTER;
+		pps_jitcnt++;
+	} else if (time_status & STA_PPSTIME) {
+		/* correct the time using the phase offset */
+		time_offset = div_s64(((s64)correction) << NTP_SCALE_SHIFT,
+				NTP_INTERVAL_FREQ);
+		/* cancel running adjtime() */
+		time_adjust = 0;
+	}
+	/* update jitter */
+	pps_jitter += (jitter - pps_jitter) >> PPS_INTMIN;
+}
+
+/*
+ * __hardpps() - discipline CPU clock oscillator to external PPS signal
+ *
+ * This routine is called at each PPS signal arrival in order to
+ * discipline the CPU clock oscillator to the PPS signal. It takes two
+ * parameters: REALTIME and MONOTONIC_RAW clock timestamps. The former
+ * is used to correct clock phase error and the latter is used to
+ * correct the frequency.
+ *
+ * This code is based on David Mills's reference nanokernel
+ * implementation. It was mostly rewritten but keeps the same idea.
+ */
+void __hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
+{
+	struct pps_normtime pts_norm, freq_norm;
+
+	pts_norm = pps_normalize_ts(*phase_ts);
+
+	/* clear the error bits, they will be set again if needed */
+	time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR);
+
+	/* indicate signal presence */
+	time_status |= STA_PPSSIGNAL;
+	pps_valid = PPS_VALID;
+
+	/* when called for the first time,
+	 * just start the frequency interval */
+	if (unlikely(pps_fbase.tv_sec == 0)) {
+		pps_fbase = *raw_ts;
+		return;
+	}
+
+	/* ok, now we have a base for frequency calculation */
+	freq_norm = pps_normalize_ts(timespec64_sub(*raw_ts, pps_fbase));
+
+	/* check that the signal is in the range
+	 * [1s - MAXFREQ us, 1s + MAXFREQ us], otherwise reject it */
+	if ((freq_norm.sec == 0) ||
+			(freq_norm.nsec > MAXFREQ * freq_norm.sec) ||
+			(freq_norm.nsec < -MAXFREQ * freq_norm.sec)) {
+		time_status |= STA_PPSJITTER;
+		/* restart the frequency calibration interval */
+		pps_fbase = *raw_ts;
+		printk_deferred(KERN_ERR "hardpps: PPSJITTER: bad pulse\n");
+		return;
+	}
+
+	/* signal is ok */
+
+	/* check if the current frequency interval is finished */
+	if (freq_norm.sec >= (1 << pps_shift)) {
+		pps_calcnt++;
+		/* restart the frequency calibration interval */
+		pps_fbase = *raw_ts;
+		hardpps_update_freq(freq_norm);
+	}
+
+	hardpps_update_phase(pts_norm.nsec);
+
+}
+#endif	/* CONFIG_NTP_PPS */
+
+static int __init ntp_tick_adj_setup(char *str)
+{
+	int rc = kstrtos64(str, 0, &ntp_tick_adj);
+	if (rc)
+		return rc;
+
+	ntp_tick_adj <<= NTP_SCALE_SHIFT;
+	return 1;
+}
+
+__setup("ntp_tick_adj=", ntp_tick_adj_setup);
+
+void __init ntp_init(void)
+{
+	ntp_clear();
+	ntp_init_cmos_sync();
+}
diff --git a/kernel/time/ntp_internal.h b/kernel/time/ntp_internal.h
new file mode 100644
index 000000000..23d1b74c3
--- /dev/null
+++ b/kernel/time/ntp_internal.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_NTP_INTERNAL_H
+#define _LINUX_NTP_INTERNAL_H
+
+extern void ntp_init(void);
+extern void ntp_clear(void);
+/* Returns how long ticks are at present, in ns / 2^NTP_SCALE_SHIFT. */
+extern u64 ntp_tick_length(void);
+extern ktime_t ntp_get_next_leap(void);
+extern int second_overflow(time64_t secs);
+extern int __do_adjtimex(struct __kernel_timex *txc,
+			 const struct timespec64 *ts,
+			 s32 *time_tai, struct audit_ntp_data *ad);
+extern void __hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts);
+
+#if defined(CONFIG_GENERIC_CMOS_UPDATE) || defined(CONFIG_RTC_SYSTOHC)
+extern void ntp_notify_cmos_timer(void);
+#else
+static inline void ntp_notify_cmos_timer(void) { }
+#endif
+
+#endif /* _LINUX_NTP_INTERNAL_H */
diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c
new file mode 100644
index 000000000..77c0c2370
--- /dev/null
+++ b/kernel/time/posix-clock.c
@@ -0,0 +1,317 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Support for dynamic clock devices
+ *
+ * Copyright (C) 2010 OMICRON electronics GmbH
+ */
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/file.h>
+#include <linux/posix-clock.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/uaccess.h>
+
+#include "posix-timers.h"
+
+/*
+ * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
+ */
+static struct posix_clock *get_posix_clock(struct file *fp)
+{
+	struct posix_clock *clk = fp->private_data;
+
+	down_read(&clk->rwsem);
+
+	if (!clk->zombie)
+		return clk;
+
+	up_read(&clk->rwsem);
+
+	return NULL;
+}
+
+static void put_posix_clock(struct posix_clock *clk)
+{
+	up_read(&clk->rwsem);
+}
+
+static ssize_t posix_clock_read(struct file *fp, char __user *buf,
+				size_t count, loff_t *ppos)
+{
+	struct posix_clock *clk = get_posix_clock(fp);
+	int err = -EINVAL;
+
+	if (!clk)
+		return -ENODEV;
+
+	if (clk->ops.read)
+		err = clk->ops.read(clk, fp->f_flags, buf, count);
+
+	put_posix_clock(clk);
+
+	return err;
+}
+
+static __poll_t posix_clock_poll(struct file *fp, poll_table *wait)
+{
+	struct posix_clock *clk = get_posix_clock(fp);
+	__poll_t result = 0;
+
+	if (!clk)
+		return EPOLLERR;
+
+	if (clk->ops.poll)
+		result = clk->ops.poll(clk, fp, wait);
+
+	put_posix_clock(clk);
+
+	return result;
+}
+
+static long posix_clock_ioctl(struct file *fp,
+			      unsigned int cmd, unsigned long arg)
+{
+	struct posix_clock *clk = get_posix_clock(fp);
+	int err = -ENOTTY;
+
+	if (!clk)
+		return -ENODEV;
+
+	if (clk->ops.ioctl)
+		err = clk->ops.ioctl(clk, cmd, arg);
+
+	put_posix_clock(clk);
+
+	return err;
+}
+
+#ifdef CONFIG_COMPAT
+static long posix_clock_compat_ioctl(struct file *fp,
+				     unsigned int cmd, unsigned long arg)
+{
+	struct posix_clock *clk = get_posix_clock(fp);
+	int err = -ENOTTY;
+
+	if (!clk)
+		return -ENODEV;
+
+	if (clk->ops.ioctl)
+		err = clk->ops.ioctl(clk, cmd, arg);
+
+	put_posix_clock(clk);
+
+	return err;
+}
+#endif
+
+static int posix_clock_open(struct inode *inode, struct file *fp)
+{
+	int err;
+	struct posix_clock *clk =
+		container_of(inode->i_cdev, struct posix_clock, cdev);
+
+	down_read(&clk->rwsem);
+
+	if (clk->zombie) {
+		err = -ENODEV;
+		goto out;
+	}
+	if (clk->ops.open)
+		err = clk->ops.open(clk, fp->f_mode);
+	else
+		err = 0;
+
+	if (!err) {
+		get_device(clk->dev);
+		fp->private_data = clk;
+	}
+out:
+	up_read(&clk->rwsem);
+	return err;
+}
+
+static int posix_clock_release(struct inode *inode, struct file *fp)
+{
+	struct posix_clock *clk = fp->private_data;
+	int err = 0;
+
+	if (clk->ops.release)
+		err = clk->ops.release(clk);
+
+	put_device(clk->dev);
+
+	fp->private_data = NULL;
+
+	return err;
+}
+
+static const struct file_operations posix_clock_file_operations = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.read		= posix_clock_read,
+	.poll		= posix_clock_poll,
+	.unlocked_ioctl	= posix_clock_ioctl,
+	.open		= posix_clock_open,
+	.release	= posix_clock_release,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= posix_clock_compat_ioctl,
+#endif
+};
+
+int posix_clock_register(struct posix_clock *clk, struct device *dev)
+{
+	int err;
+
+	init_rwsem(&clk->rwsem);
+
+	cdev_init(&clk->cdev, &posix_clock_file_operations);
+	err = cdev_device_add(&clk->cdev, dev);
+	if (err) {
+		pr_err("%s unable to add device %d:%d\n",
+			dev_name(dev), MAJOR(dev->devt), MINOR(dev->devt));
+		return err;
+	}
+	clk->cdev.owner = clk->ops.owner;
+	clk->dev = dev;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(posix_clock_register);
+
+void posix_clock_unregister(struct posix_clock *clk)
+{
+	cdev_device_del(&clk->cdev, clk->dev);
+
+	down_write(&clk->rwsem);
+	clk->zombie = true;
+	up_write(&clk->rwsem);
+
+	put_device(clk->dev);
+}
+EXPORT_SYMBOL_GPL(posix_clock_unregister);
+
+struct posix_clock_desc {
+	struct file *fp;
+	struct posix_clock *clk;
+};
+
+static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
+{
+	struct file *fp = fget(clockid_to_fd(id));
+	int err = -EINVAL;
+
+	if (!fp)
+		return err;
+
+	if (fp->f_op->open != posix_clock_open || !fp->private_data)
+		goto out;
+
+	cd->fp = fp;
+	cd->clk = get_posix_clock(fp);
+
+	err = cd->clk ? 0 : -ENODEV;
+out:
+	if (err)
+		fput(fp);
+	return err;
+}
+
+static void put_clock_desc(struct posix_clock_desc *cd)
+{
+	put_posix_clock(cd->clk);
+	fput(cd->fp);
+}
+
+static int pc_clock_adjtime(clockid_t id, struct __kernel_timex *tx)
+{
+	struct posix_clock_desc cd;
+	int err;
+
+	err = get_clock_desc(id, &cd);
+	if (err)
+		return err;
+
+	if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
+		err = -EACCES;
+		goto out;
+	}
+
+	if (cd.clk->ops.clock_adjtime)
+		err = cd.clk->ops.clock_adjtime(cd.clk, tx);
+	else
+		err = -EOPNOTSUPP;
+out:
+	put_clock_desc(&cd);
+
+	return err;
+}
+
+static int pc_clock_gettime(clockid_t id, struct timespec64 *ts)
+{
+	struct posix_clock_desc cd;
+	int err;
+
+	err = get_clock_desc(id, &cd);
+	if (err)
+		return err;
+
+	if (cd.clk->ops.clock_gettime)
+		err = cd.clk->ops.clock_gettime(cd.clk, ts);
+	else
+		err = -EOPNOTSUPP;
+
+	put_clock_desc(&cd);
+
+	return err;
+}
+
+static int pc_clock_getres(clockid_t id, struct timespec64 *ts)
+{
+	struct posix_clock_desc cd;
+	int err;
+
+	err = get_clock_desc(id, &cd);
+	if (err)
+		return err;
+
+	if (cd.clk->ops.clock_getres)
+		err = cd.clk->ops.clock_getres(cd.clk, ts);
+	else
+		err = -EOPNOTSUPP;
+
+	put_clock_desc(&cd);
+
+	return err;
+}
+
+static int pc_clock_settime(clockid_t id, const struct timespec64 *ts)
+{
+	struct posix_clock_desc cd;
+	int err;
+
+	err = get_clock_desc(id, &cd);
+	if (err)
+		return err;
+
+	if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
+		err = -EACCES;
+		goto out;
+	}
+
+	if (cd.clk->ops.clock_settime)
+		err = cd.clk->ops.clock_settime(cd.clk, ts);
+	else
+		err = -EOPNOTSUPP;
+out:
+	put_clock_desc(&cd);
+
+	return err;
+}
+
+const struct k_clock clock_posix_dynamic = {
+	.clock_getres		= pc_clock_getres,
+	.clock_set		= pc_clock_settime,
+	.clock_get_timespec	= pc_clock_gettime,
+	.clock_adj		= pc_clock_adjtime,
+};
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
new file mode 100644
index 000000000..44b25ff35
--- /dev/null
+++ b/kernel/time/posix-cpu-timers.c
@@ -0,0 +1,1693 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Implement CPU time clocks for the POSIX clock interface.
+ */
+
+#include <linux/sched/signal.h>
+#include <linux/sched/cputime.h>
+#include <linux/posix-timers.h>
+#include <linux/errno.h>
+#include <linux/math64.h>
+#include <linux/uaccess.h>
+#include <linux/kernel_stat.h>
+#include <trace/events/timer.h>
+#include <linux/tick.h>
+#include <linux/workqueue.h>
+#include <linux/compat.h>
+#include <linux/sched/deadline.h>
+#include <linux/task_work.h>
+
+#include "posix-timers.h"
+
+static void posix_cpu_timer_rearm(struct k_itimer *timer);
+
+void posix_cputimers_group_init(struct posix_cputimers *pct, u64 cpu_limit)
+{
+	posix_cputimers_init(pct);
+	if (cpu_limit != RLIM_INFINITY) {
+		pct->bases[CPUCLOCK_PROF].nextevt = cpu_limit * NSEC_PER_SEC;
+		pct->timers_active = true;
+	}
+}
+
+/*
+ * Called after updating RLIMIT_CPU to run cpu timer and update
+ * tsk->signal->posix_cputimers.bases[clock].nextevt expiration cache if
+ * necessary. Needs siglock protection since other code may update the
+ * expiration cache as well.
+ *
+ * Returns 0 on success, -ESRCH on failure.  Can fail if the task is exiting and
+ * we cannot lock_task_sighand.  Cannot fail if task is current.
+ */
+int update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
+{
+	u64 nsecs = rlim_new * NSEC_PER_SEC;
+	unsigned long irq_fl;
+
+	if (!lock_task_sighand(task, &irq_fl))
+		return -ESRCH;
+	set_process_cpu_timer(task, CPUCLOCK_PROF, &nsecs, NULL);
+	unlock_task_sighand(task, &irq_fl);
+	return 0;
+}
+
+/*
+ * Functions for validating access to tasks.
+ */
+static struct pid *pid_for_clock(const clockid_t clock, bool gettime)
+{
+	const bool thread = !!CPUCLOCK_PERTHREAD(clock);
+	const pid_t upid = CPUCLOCK_PID(clock);
+	struct pid *pid;
+
+	if (CPUCLOCK_WHICH(clock) >= CPUCLOCK_MAX)
+		return NULL;
+
+	/*
+	 * If the encoded PID is 0, then the timer is targeted at current
+	 * or the process to which current belongs.
+	 */
+	if (upid == 0)
+		return thread ? task_pid(current) : task_tgid(current);
+
+	pid = find_vpid(upid);
+	if (!pid)
+		return NULL;
+
+	if (thread) {
+		struct task_struct *tsk = pid_task(pid, PIDTYPE_PID);
+		return (tsk && same_thread_group(tsk, current)) ? pid : NULL;
+	}
+
+	/*
+	 * For clock_gettime(PROCESS) allow finding the process by
+	 * with the pid of the current task.  The code needs the tgid
+	 * of the process so that pid_task(pid, PIDTYPE_TGID) can be
+	 * used to find the process.
+	 */
+	if (gettime && (pid == task_pid(current)))
+		return task_tgid(current);
+
+	/*
+	 * For processes require that pid identifies a process.
+	 */
+	return pid_has_task(pid, PIDTYPE_TGID) ? pid : NULL;
+}
+
+static inline int validate_clock_permissions(const clockid_t clock)
+{
+	int ret;
+
+	rcu_read_lock();
+	ret = pid_for_clock(clock, false) ? 0 : -EINVAL;
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static inline enum pid_type clock_pid_type(const clockid_t clock)
+{
+	return CPUCLOCK_PERTHREAD(clock) ? PIDTYPE_PID : PIDTYPE_TGID;
+}
+
+static inline struct task_struct *cpu_timer_task_rcu(struct k_itimer *timer)
+{
+	return pid_task(timer->it.cpu.pid, clock_pid_type(timer->it_clock));
+}
+
+/*
+ * Update expiry time from increment, and increase overrun count,
+ * given the current clock sample.
+ */
+static u64 bump_cpu_timer(struct k_itimer *timer, u64 now)
+{
+	u64 delta, incr, expires = timer->it.cpu.node.expires;
+	int i;
+
+	if (!timer->it_interval)
+		return expires;
+
+	if (now < expires)
+		return expires;
+
+	incr = timer->it_interval;
+	delta = now + incr - expires;
+
+	/* Don't use (incr*2 < delta), incr*2 might overflow. */
+	for (i = 0; incr < delta - incr; i++)
+		incr = incr << 1;
+
+	for (; i >= 0; incr >>= 1, i--) {
+		if (delta < incr)
+			continue;
+
+		timer->it.cpu.node.expires += incr;
+		timer->it_overrun += 1LL << i;
+		delta -= incr;
+	}
+	return timer->it.cpu.node.expires;
+}
+
+/* Check whether all cache entries contain U64_MAX, i.e. eternal expiry time */
+static inline bool expiry_cache_is_inactive(const struct posix_cputimers *pct)
+{
+	return !(~pct->bases[CPUCLOCK_PROF].nextevt |
+		 ~pct->bases[CPUCLOCK_VIRT].nextevt |
+		 ~pct->bases[CPUCLOCK_SCHED].nextevt);
+}
+
+static int
+posix_cpu_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
+{
+	int error = validate_clock_permissions(which_clock);
+
+	if (!error) {
+		tp->tv_sec = 0;
+		tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
+		if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
+			/*
+			 * If sched_clock is using a cycle counter, we
+			 * don't have any idea of its true resolution
+			 * exported, but it is much more than 1s/HZ.
+			 */
+			tp->tv_nsec = 1;
+		}
+	}
+	return error;
+}
+
+static int
+posix_cpu_clock_set(const clockid_t clock, const struct timespec64 *tp)
+{
+	int error = validate_clock_permissions(clock);
+
+	/*
+	 * You can never reset a CPU clock, but we check for other errors
+	 * in the call before failing with EPERM.
+	 */
+	return error ? : -EPERM;
+}
+
+/*
+ * Sample a per-thread clock for the given task. clkid is validated.
+ */
+static u64 cpu_clock_sample(const clockid_t clkid, struct task_struct *p)
+{
+	u64 utime, stime;
+
+	if (clkid == CPUCLOCK_SCHED)
+		return task_sched_runtime(p);
+
+	task_cputime(p, &utime, &stime);
+
+	switch (clkid) {
+	case CPUCLOCK_PROF:
+		return utime + stime;
+	case CPUCLOCK_VIRT:
+		return utime;
+	default:
+		WARN_ON_ONCE(1);
+	}
+	return 0;
+}
+
+static inline void store_samples(u64 *samples, u64 stime, u64 utime, u64 rtime)
+{
+	samples[CPUCLOCK_PROF] = stime + utime;
+	samples[CPUCLOCK_VIRT] = utime;
+	samples[CPUCLOCK_SCHED] = rtime;
+}
+
+static void task_sample_cputime(struct task_struct *p, u64 *samples)
+{
+	u64 stime, utime;
+
+	task_cputime(p, &utime, &stime);
+	store_samples(samples, stime, utime, p->se.sum_exec_runtime);
+}
+
+static void proc_sample_cputime_atomic(struct task_cputime_atomic *at,
+				       u64 *samples)
+{
+	u64 stime, utime, rtime;
+
+	utime = atomic64_read(&at->utime);
+	stime = atomic64_read(&at->stime);
+	rtime = atomic64_read(&at->sum_exec_runtime);
+	store_samples(samples, stime, utime, rtime);
+}
+
+/*
+ * Set cputime to sum_cputime if sum_cputime > cputime. Use cmpxchg
+ * to avoid race conditions with concurrent updates to cputime.
+ */
+static inline void __update_gt_cputime(atomic64_t *cputime, u64 sum_cputime)
+{
+	u64 curr_cputime;
+retry:
+	curr_cputime = atomic64_read(cputime);
+	if (sum_cputime > curr_cputime) {
+		if (atomic64_cmpxchg(cputime, curr_cputime, sum_cputime) != curr_cputime)
+			goto retry;
+	}
+}
+
+static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic,
+			      struct task_cputime *sum)
+{
+	__update_gt_cputime(&cputime_atomic->utime, sum->utime);
+	__update_gt_cputime(&cputime_atomic->stime, sum->stime);
+	__update_gt_cputime(&cputime_atomic->sum_exec_runtime, sum->sum_exec_runtime);
+}
+
+/**
+ * thread_group_sample_cputime - Sample cputime for a given task
+ * @tsk:	Task for which cputime needs to be started
+ * @samples:	Storage for time samples
+ *
+ * Called from sys_getitimer() to calculate the expiry time of an active
+ * timer. That means group cputime accounting is already active. Called
+ * with task sighand lock held.
+ *
+ * Updates @times with an uptodate sample of the thread group cputimes.
+ */
+void thread_group_sample_cputime(struct task_struct *tsk, u64 *samples)
+{
+	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
+	struct posix_cputimers *pct = &tsk->signal->posix_cputimers;
+
+	WARN_ON_ONCE(!pct->timers_active);
+
+	proc_sample_cputime_atomic(&cputimer->cputime_atomic, samples);
+}
+
+/**
+ * thread_group_start_cputime - Start cputime and return a sample
+ * @tsk:	Task for which cputime needs to be started
+ * @samples:	Storage for time samples
+ *
+ * The thread group cputime accounting is avoided when there are no posix
+ * CPU timers armed. Before starting a timer it's required to check whether
+ * the time accounting is active. If not, a full update of the atomic
+ * accounting store needs to be done and the accounting enabled.
+ *
+ * Updates @times with an uptodate sample of the thread group cputimes.
+ */
+static void thread_group_start_cputime(struct task_struct *tsk, u64 *samples)
+{
+	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
+	struct posix_cputimers *pct = &tsk->signal->posix_cputimers;
+
+	lockdep_assert_task_sighand_held(tsk);
+
+	/* Check if cputimer isn't running. This is accessed without locking. */
+	if (!READ_ONCE(pct->timers_active)) {
+		struct task_cputime sum;
+
+		/*
+		 * The POSIX timer interface allows for absolute time expiry
+		 * values through the TIMER_ABSTIME flag, therefore we have
+		 * to synchronize the timer to the clock every time we start it.
+		 */
+		thread_group_cputime(tsk, &sum);
+		update_gt_cputime(&cputimer->cputime_atomic, &sum);
+
+		/*
+		 * We're setting timers_active without a lock. Ensure this
+		 * only gets written to in one operation. We set it after
+		 * update_gt_cputime() as a small optimization, but
+		 * barriers are not required because update_gt_cputime()
+		 * can handle concurrent updates.
+		 */
+		WRITE_ONCE(pct->timers_active, true);
+	}
+	proc_sample_cputime_atomic(&cputimer->cputime_atomic, samples);
+}
+
+static void __thread_group_cputime(struct task_struct *tsk, u64 *samples)
+{
+	struct task_cputime ct;
+
+	thread_group_cputime(tsk, &ct);
+	store_samples(samples, ct.stime, ct.utime, ct.sum_exec_runtime);
+}
+
+/*
+ * Sample a process (thread group) clock for the given task clkid. If the
+ * group's cputime accounting is already enabled, read the atomic
+ * store. Otherwise a full update is required.  clkid is already validated.
+ */
+static u64 cpu_clock_sample_group(const clockid_t clkid, struct task_struct *p,
+				  bool start)
+{
+	struct thread_group_cputimer *cputimer = &p->signal->cputimer;
+	struct posix_cputimers *pct = &p->signal->posix_cputimers;
+	u64 samples[CPUCLOCK_MAX];
+
+	if (!READ_ONCE(pct->timers_active)) {
+		if (start)
+			thread_group_start_cputime(p, samples);
+		else
+			__thread_group_cputime(p, samples);
+	} else {
+		proc_sample_cputime_atomic(&cputimer->cputime_atomic, samples);
+	}
+
+	return samples[clkid];
+}
+
+static int posix_cpu_clock_get(const clockid_t clock, struct timespec64 *tp)
+{
+	const clockid_t clkid = CPUCLOCK_WHICH(clock);
+	struct task_struct *tsk;
+	u64 t;
+
+	rcu_read_lock();
+	tsk = pid_task(pid_for_clock(clock, true), clock_pid_type(clock));
+	if (!tsk) {
+		rcu_read_unlock();
+		return -EINVAL;
+	}
+
+	if (CPUCLOCK_PERTHREAD(clock))
+		t = cpu_clock_sample(clkid, tsk);
+	else
+		t = cpu_clock_sample_group(clkid, tsk, false);
+	rcu_read_unlock();
+
+	*tp = ns_to_timespec64(t);
+	return 0;
+}
+
+/*
+ * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
+ * This is called from sys_timer_create() and do_cpu_nanosleep() with the
+ * new timer already all-zeros initialized.
+ */
+static int posix_cpu_timer_create(struct k_itimer *new_timer)
+{
+	static struct lock_class_key posix_cpu_timers_key;
+	struct pid *pid;
+
+	rcu_read_lock();
+	pid = pid_for_clock(new_timer->it_clock, false);
+	if (!pid) {
+		rcu_read_unlock();
+		return -EINVAL;
+	}
+
+	/*
+	 * If posix timer expiry is handled in task work context then
+	 * timer::it_lock can be taken without disabling interrupts as all
+	 * other locking happens in task context. This requires a separate
+	 * lock class key otherwise regular posix timer expiry would record
+	 * the lock class being taken in interrupt context and generate a
+	 * false positive warning.
+	 */
+	if (IS_ENABLED(CONFIG_POSIX_CPU_TIMERS_TASK_WORK))
+		lockdep_set_class(&new_timer->it_lock, &posix_cpu_timers_key);
+
+	new_timer->kclock = &clock_posix_cpu;
+	timerqueue_init(&new_timer->it.cpu.node);
+	new_timer->it.cpu.pid = get_pid(pid);
+	rcu_read_unlock();
+	return 0;
+}
+
+static struct posix_cputimer_base *timer_base(struct k_itimer *timer,
+					      struct task_struct *tsk)
+{
+	int clkidx = CPUCLOCK_WHICH(timer->it_clock);
+
+	if (CPUCLOCK_PERTHREAD(timer->it_clock))
+		return tsk->posix_cputimers.bases + clkidx;
+	else
+		return tsk->signal->posix_cputimers.bases + clkidx;
+}
+
+/*
+ * Force recalculating the base earliest expiration on the next tick.
+ * This will also re-evaluate the need to keep around the process wide
+ * cputime counter and tick dependency and eventually shut these down
+ * if necessary.
+ */
+static void trigger_base_recalc_expires(struct k_itimer *timer,
+					struct task_struct *tsk)
+{
+	struct posix_cputimer_base *base = timer_base(timer, tsk);
+
+	base->nextevt = 0;
+}
+
+/*
+ * Dequeue the timer and reset the base if it was its earliest expiration.
+ * It makes sure the next tick recalculates the base next expiration so we
+ * don't keep the costly process wide cputime counter around for a random
+ * amount of time, along with the tick dependency.
+ *
+ * If another timer gets queued between this and the next tick, its
+ * expiration will update the base next event if necessary on the next
+ * tick.
+ */
+static void disarm_timer(struct k_itimer *timer, struct task_struct *p)
+{
+	struct cpu_timer *ctmr = &timer->it.cpu;
+	struct posix_cputimer_base *base;
+
+	if (!cpu_timer_dequeue(ctmr))
+		return;
+
+	base = timer_base(timer, p);
+	if (cpu_timer_getexpires(ctmr) == base->nextevt)
+		trigger_base_recalc_expires(timer, p);
+}
+
+
+/*
+ * Clean up a CPU-clock timer that is about to be destroyed.
+ * This is called from timer deletion with the timer already locked.
+ * If we return TIMER_RETRY, it's necessary to release the timer's lock
+ * and try again.  (This happens when the timer is in the middle of firing.)
+ */
+static int posix_cpu_timer_del(struct k_itimer *timer)
+{
+	struct cpu_timer *ctmr = &timer->it.cpu;
+	struct sighand_struct *sighand;
+	struct task_struct *p;
+	unsigned long flags;
+	int ret = 0;
+
+	rcu_read_lock();
+	p = cpu_timer_task_rcu(timer);
+	if (!p)
+		goto out;
+
+	/*
+	 * Protect against sighand release/switch in exit/exec and process/
+	 * thread timer list entry concurrent read/writes.
+	 */
+	sighand = lock_task_sighand(p, &flags);
+	if (unlikely(sighand == NULL)) {
+		/*
+		 * This raced with the reaping of the task. The exit cleanup
+		 * should have removed this timer from the timer queue.
+		 */
+		WARN_ON_ONCE(ctmr->head || timerqueue_node_queued(&ctmr->node));
+	} else {
+		if (timer->it.cpu.firing)
+			ret = TIMER_RETRY;
+		else
+			disarm_timer(timer, p);
+
+		unlock_task_sighand(p, &flags);
+	}
+
+out:
+	rcu_read_unlock();
+	if (!ret)
+		put_pid(ctmr->pid);
+
+	return ret;
+}
+
+static void cleanup_timerqueue(struct timerqueue_head *head)
+{
+	struct timerqueue_node *node;
+	struct cpu_timer *ctmr;
+
+	while ((node = timerqueue_getnext(head))) {
+		timerqueue_del(head, node);
+		ctmr = container_of(node, struct cpu_timer, node);
+		ctmr->head = NULL;
+	}
+}
+
+/*
+ * Clean out CPU timers which are still armed when a thread exits. The
+ * timers are only removed from the list. No other updates are done. The
+ * corresponding posix timers are still accessible, but cannot be rearmed.
+ *
+ * This must be called with the siglock held.
+ */
+static void cleanup_timers(struct posix_cputimers *pct)
+{
+	cleanup_timerqueue(&pct->bases[CPUCLOCK_PROF].tqhead);
+	cleanup_timerqueue(&pct->bases[CPUCLOCK_VIRT].tqhead);
+	cleanup_timerqueue(&pct->bases[CPUCLOCK_SCHED].tqhead);
+}
+
+/*
+ * These are both called with the siglock held, when the current thread
+ * is being reaped.  When the final (leader) thread in the group is reaped,
+ * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
+ */
+void posix_cpu_timers_exit(struct task_struct *tsk)
+{
+	cleanup_timers(&tsk->posix_cputimers);
+}
+void posix_cpu_timers_exit_group(struct task_struct *tsk)
+{
+	cleanup_timers(&tsk->signal->posix_cputimers);
+}
+
+/*
+ * Insert the timer on the appropriate list before any timers that
+ * expire later.  This must be called with the sighand lock held.
+ */
+static void arm_timer(struct k_itimer *timer, struct task_struct *p)
+{
+	struct posix_cputimer_base *base = timer_base(timer, p);
+	struct cpu_timer *ctmr = &timer->it.cpu;
+	u64 newexp = cpu_timer_getexpires(ctmr);
+
+	if (!cpu_timer_enqueue(&base->tqhead, ctmr))
+		return;
+
+	/*
+	 * We are the new earliest-expiring POSIX 1.b timer, hence
+	 * need to update expiration cache. Take into account that
+	 * for process timers we share expiration cache with itimers
+	 * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
+	 */
+	if (newexp < base->nextevt)
+		base->nextevt = newexp;
+
+	if (CPUCLOCK_PERTHREAD(timer->it_clock))
+		tick_dep_set_task(p, TICK_DEP_BIT_POSIX_TIMER);
+	else
+		tick_dep_set_signal(p, TICK_DEP_BIT_POSIX_TIMER);
+}
+
+/*
+ * The timer is locked, fire it and arrange for its reload.
+ */
+static void cpu_timer_fire(struct k_itimer *timer)
+{
+	struct cpu_timer *ctmr = &timer->it.cpu;
+
+	if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
+		/*
+		 * User don't want any signal.
+		 */
+		cpu_timer_setexpires(ctmr, 0);
+	} else if (unlikely(timer->sigq == NULL)) {
+		/*
+		 * This a special case for clock_nanosleep,
+		 * not a normal timer from sys_timer_create.
+		 */
+		wake_up_process(timer->it_process);
+		cpu_timer_setexpires(ctmr, 0);
+	} else if (!timer->it_interval) {
+		/*
+		 * One-shot timer.  Clear it as soon as it's fired.
+		 */
+		posix_timer_event(timer, 0);
+		cpu_timer_setexpires(ctmr, 0);
+	} else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
+		/*
+		 * The signal did not get queued because the signal
+		 * was ignored, so we won't get any callback to
+		 * reload the timer.  But we need to keep it
+		 * ticking in case the signal is deliverable next time.
+		 */
+		posix_cpu_timer_rearm(timer);
+		++timer->it_requeue_pending;
+	}
+}
+
+/*
+ * Guts of sys_timer_settime for CPU timers.
+ * This is called with the timer locked and interrupts disabled.
+ * If we return TIMER_RETRY, it's necessary to release the timer's lock
+ * and try again.  (This happens when the timer is in the middle of firing.)
+ */
+static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
+			       struct itimerspec64 *new, struct itimerspec64 *old)
+{
+	clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
+	u64 old_expires, new_expires, old_incr, val;
+	struct cpu_timer *ctmr = &timer->it.cpu;
+	struct sighand_struct *sighand;
+	struct task_struct *p;
+	unsigned long flags;
+	int ret = 0;
+
+	rcu_read_lock();
+	p = cpu_timer_task_rcu(timer);
+	if (!p) {
+		/*
+		 * If p has just been reaped, we can no
+		 * longer get any information about it at all.
+		 */
+		rcu_read_unlock();
+		return -ESRCH;
+	}
+
+	/*
+	 * Use the to_ktime conversion because that clamps the maximum
+	 * value to KTIME_MAX and avoid multiplication overflows.
+	 */
+	new_expires = ktime_to_ns(timespec64_to_ktime(new->it_value));
+
+	/*
+	 * Protect against sighand release/switch in exit/exec and p->cpu_timers
+	 * and p->signal->cpu_timers read/write in arm_timer()
+	 */
+	sighand = lock_task_sighand(p, &flags);
+	/*
+	 * If p has just been reaped, we can no
+	 * longer get any information about it at all.
+	 */
+	if (unlikely(sighand == NULL)) {
+		rcu_read_unlock();
+		return -ESRCH;
+	}
+
+	/*
+	 * Disarm any old timer after extracting its expiry time.
+	 */
+	old_incr = timer->it_interval;
+	old_expires = cpu_timer_getexpires(ctmr);
+
+	if (unlikely(timer->it.cpu.firing)) {
+		timer->it.cpu.firing = -1;
+		ret = TIMER_RETRY;
+	} else {
+		cpu_timer_dequeue(ctmr);
+	}
+
+	/*
+	 * We need to sample the current value to convert the new
+	 * value from to relative and absolute, and to convert the
+	 * old value from absolute to relative.  To set a process
+	 * timer, we need a sample to balance the thread expiry
+	 * times (in arm_timer).  With an absolute time, we must
+	 * check if it's already passed.  In short, we need a sample.
+	 */
+	if (CPUCLOCK_PERTHREAD(timer->it_clock))
+		val = cpu_clock_sample(clkid, p);
+	else
+		val = cpu_clock_sample_group(clkid, p, true);
+
+	if (old) {
+		if (old_expires == 0) {
+			old->it_value.tv_sec = 0;
+			old->it_value.tv_nsec = 0;
+		} else {
+			/*
+			 * Update the timer in case it has overrun already.
+			 * If it has, we'll report it as having overrun and
+			 * with the next reloaded timer already ticking,
+			 * though we are swallowing that pending
+			 * notification here to install the new setting.
+			 */
+			u64 exp = bump_cpu_timer(timer, val);
+
+			if (val < exp) {
+				old_expires = exp - val;
+				old->it_value = ns_to_timespec64(old_expires);
+			} else {
+				old->it_value.tv_nsec = 1;
+				old->it_value.tv_sec = 0;
+			}
+		}
+	}
+
+	if (unlikely(ret)) {
+		/*
+		 * We are colliding with the timer actually firing.
+		 * Punt after filling in the timer's old value, and
+		 * disable this firing since we are already reporting
+		 * it as an overrun (thanks to bump_cpu_timer above).
+		 */
+		unlock_task_sighand(p, &flags);
+		goto out;
+	}
+
+	if (new_expires != 0 && !(timer_flags & TIMER_ABSTIME)) {
+		new_expires += val;
+	}
+
+	/*
+	 * Install the new expiry time (or zero).
+	 * For a timer with no notification action, we don't actually
+	 * arm the timer (we'll just fake it for timer_gettime).
+	 */
+	cpu_timer_setexpires(ctmr, new_expires);
+	if (new_expires != 0 && val < new_expires) {
+		arm_timer(timer, p);
+	}
+
+	unlock_task_sighand(p, &flags);
+	/*
+	 * Install the new reload setting, and
+	 * set up the signal and overrun bookkeeping.
+	 */
+	timer->it_interval = timespec64_to_ktime(new->it_interval);
+
+	/*
+	 * This acts as a modification timestamp for the timer,
+	 * so any automatic reload attempt will punt on seeing
+	 * that we have reset the timer manually.
+	 */
+	timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
+		~REQUEUE_PENDING;
+	timer->it_overrun_last = 0;
+	timer->it_overrun = -1;
+
+	if (val >= new_expires) {
+		if (new_expires != 0) {
+			/*
+			 * The designated time already passed, so we notify
+			 * immediately, even if the thread never runs to
+			 * accumulate more time on this clock.
+			 */
+			cpu_timer_fire(timer);
+		}
+
+		/*
+		 * Make sure we don't keep around the process wide cputime
+		 * counter or the tick dependency if they are not necessary.
+		 */
+		sighand = lock_task_sighand(p, &flags);
+		if (!sighand)
+			goto out;
+
+		if (!cpu_timer_queued(ctmr))
+			trigger_base_recalc_expires(timer, p);
+
+		unlock_task_sighand(p, &flags);
+	}
+ out:
+	rcu_read_unlock();
+	if (old)
+		old->it_interval = ns_to_timespec64(old_incr);
+
+	return ret;
+}
+
+static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp)
+{
+	clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
+	struct cpu_timer *ctmr = &timer->it.cpu;
+	u64 now, expires = cpu_timer_getexpires(ctmr);
+	struct task_struct *p;
+
+	rcu_read_lock();
+	p = cpu_timer_task_rcu(timer);
+	if (!p)
+		goto out;
+
+	/*
+	 * Easy part: convert the reload time.
+	 */
+	itp->it_interval = ktime_to_timespec64(timer->it_interval);
+
+	if (!expires)
+		goto out;
+
+	/*
+	 * Sample the clock to take the difference with the expiry time.
+	 */
+	if (CPUCLOCK_PERTHREAD(timer->it_clock))
+		now = cpu_clock_sample(clkid, p);
+	else
+		now = cpu_clock_sample_group(clkid, p, false);
+
+	if (now < expires) {
+		itp->it_value = ns_to_timespec64(expires - now);
+	} else {
+		/*
+		 * The timer should have expired already, but the firing
+		 * hasn't taken place yet.  Say it's just about to expire.
+		 */
+		itp->it_value.tv_nsec = 1;
+		itp->it_value.tv_sec = 0;
+	}
+out:
+	rcu_read_unlock();
+}
+
+#define MAX_COLLECTED	20
+
+static u64 collect_timerqueue(struct timerqueue_head *head,
+			      struct list_head *firing, u64 now)
+{
+	struct timerqueue_node *next;
+	int i = 0;
+
+	while ((next = timerqueue_getnext(head))) {
+		struct cpu_timer *ctmr;
+		u64 expires;
+
+		ctmr = container_of(next, struct cpu_timer, node);
+		expires = cpu_timer_getexpires(ctmr);
+		/* Limit the number of timers to expire at once */
+		if (++i == MAX_COLLECTED || now < expires)
+			return expires;
+
+		ctmr->firing = 1;
+		/* See posix_cpu_timer_wait_running() */
+		rcu_assign_pointer(ctmr->handling, current);
+		cpu_timer_dequeue(ctmr);
+		list_add_tail(&ctmr->elist, firing);
+	}
+
+	return U64_MAX;
+}
+
+static void collect_posix_cputimers(struct posix_cputimers *pct, u64 *samples,
+				    struct list_head *firing)
+{
+	struct posix_cputimer_base *base = pct->bases;
+	int i;
+
+	for (i = 0; i < CPUCLOCK_MAX; i++, base++) {
+		base->nextevt = collect_timerqueue(&base->tqhead, firing,
+						    samples[i]);
+	}
+}
+
+static inline void check_dl_overrun(struct task_struct *tsk)
+{
+	if (tsk->dl.dl_overrun) {
+		tsk->dl.dl_overrun = 0;
+		send_signal_locked(SIGXCPU, SEND_SIG_PRIV, tsk, PIDTYPE_TGID);
+	}
+}
+
+static bool check_rlimit(u64 time, u64 limit, int signo, bool rt, bool hard)
+{
+	if (time < limit)
+		return false;
+
+	if (print_fatal_signals) {
+		pr_info("%s Watchdog Timeout (%s): %s[%d]\n",
+			rt ? "RT" : "CPU", hard ? "hard" : "soft",
+			current->comm, task_pid_nr(current));
+	}
+	send_signal_locked(signo, SEND_SIG_PRIV, current, PIDTYPE_TGID);
+	return true;
+}
+
+/*
+ * Check for any per-thread CPU timers that have fired and move them off
+ * the tsk->cpu_timers[N] list onto the firing list.  Here we update the
+ * tsk->it_*_expires values to reflect the remaining thread CPU timers.
+ */
+static void check_thread_timers(struct task_struct *tsk,
+				struct list_head *firing)
+{
+	struct posix_cputimers *pct = &tsk->posix_cputimers;
+	u64 samples[CPUCLOCK_MAX];
+	unsigned long soft;
+
+	if (dl_task(tsk))
+		check_dl_overrun(tsk);
+
+	if (expiry_cache_is_inactive(pct))
+		return;
+
+	task_sample_cputime(tsk, samples);
+	collect_posix_cputimers(pct, samples, firing);
+
+	/*
+	 * Check for the special case thread timers.
+	 */
+	soft = task_rlimit(tsk, RLIMIT_RTTIME);
+	if (soft != RLIM_INFINITY) {
+		/* Task RT timeout is accounted in jiffies. RTTIME is usec */
+		unsigned long rttime = tsk->rt.timeout * (USEC_PER_SEC / HZ);
+		unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME);
+
+		/* At the hard limit, send SIGKILL. No further action. */
+		if (hard != RLIM_INFINITY &&
+		    check_rlimit(rttime, hard, SIGKILL, true, true))
+			return;
+
+		/* At the soft limit, send a SIGXCPU every second */
+		if (check_rlimit(rttime, soft, SIGXCPU, true, false)) {
+			soft += USEC_PER_SEC;
+			tsk->signal->rlim[RLIMIT_RTTIME].rlim_cur = soft;
+		}
+	}
+
+	if (expiry_cache_is_inactive(pct))
+		tick_dep_clear_task(tsk, TICK_DEP_BIT_POSIX_TIMER);
+}
+
+static inline void stop_process_timers(struct signal_struct *sig)
+{
+	struct posix_cputimers *pct = &sig->posix_cputimers;
+
+	/* Turn off the active flag. This is done without locking. */
+	WRITE_ONCE(pct->timers_active, false);
+	tick_dep_clear_signal(sig, TICK_DEP_BIT_POSIX_TIMER);
+}
+
+static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
+			     u64 *expires, u64 cur_time, int signo)
+{
+	if (!it->expires)
+		return;
+
+	if (cur_time >= it->expires) {
+		if (it->incr)
+			it->expires += it->incr;
+		else
+			it->expires = 0;
+
+		trace_itimer_expire(signo == SIGPROF ?
+				    ITIMER_PROF : ITIMER_VIRTUAL,
+				    task_tgid(tsk), cur_time);
+		send_signal_locked(signo, SEND_SIG_PRIV, tsk, PIDTYPE_TGID);
+	}
+
+	if (it->expires && it->expires < *expires)
+		*expires = it->expires;
+}
+
+/*
+ * Check for any per-thread CPU timers that have fired and move them
+ * off the tsk->*_timers list onto the firing list.  Per-thread timers
+ * have already been taken off.
+ */
+static void check_process_timers(struct task_struct *tsk,
+				 struct list_head *firing)
+{
+	struct signal_struct *const sig = tsk->signal;
+	struct posix_cputimers *pct = &sig->posix_cputimers;
+	u64 samples[CPUCLOCK_MAX];
+	unsigned long soft;
+
+	/*
+	 * If there are no active process wide timers (POSIX 1.b, itimers,
+	 * RLIMIT_CPU) nothing to check. Also skip the process wide timer
+	 * processing when there is already another task handling them.
+	 */
+	if (!READ_ONCE(pct->timers_active) || pct->expiry_active)
+		return;
+
+	/*
+	 * Signify that a thread is checking for process timers.
+	 * Write access to this field is protected by the sighand lock.
+	 */
+	pct->expiry_active = true;
+
+	/*
+	 * Collect the current process totals. Group accounting is active
+	 * so the sample can be taken directly.
+	 */
+	proc_sample_cputime_atomic(&sig->cputimer.cputime_atomic, samples);
+	collect_posix_cputimers(pct, samples, firing);
+
+	/*
+	 * Check for the special case process timers.
+	 */
+	check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF],
+			 &pct->bases[CPUCLOCK_PROF].nextevt,
+			 samples[CPUCLOCK_PROF], SIGPROF);
+	check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT],
+			 &pct->bases[CPUCLOCK_VIRT].nextevt,
+			 samples[CPUCLOCK_VIRT], SIGVTALRM);
+
+	soft = task_rlimit(tsk, RLIMIT_CPU);
+	if (soft != RLIM_INFINITY) {
+		/* RLIMIT_CPU is in seconds. Samples are nanoseconds */
+		unsigned long hard = task_rlimit_max(tsk, RLIMIT_CPU);
+		u64 ptime = samples[CPUCLOCK_PROF];
+		u64 softns = (u64)soft * NSEC_PER_SEC;
+		u64 hardns = (u64)hard * NSEC_PER_SEC;
+
+		/* At the hard limit, send SIGKILL. No further action. */
+		if (hard != RLIM_INFINITY &&
+		    check_rlimit(ptime, hardns, SIGKILL, false, true))
+			return;
+
+		/* At the soft limit, send a SIGXCPU every second */
+		if (check_rlimit(ptime, softns, SIGXCPU, false, false)) {
+			sig->rlim[RLIMIT_CPU].rlim_cur = soft + 1;
+			softns += NSEC_PER_SEC;
+		}
+
+		/* Update the expiry cache */
+		if (softns < pct->bases[CPUCLOCK_PROF].nextevt)
+			pct->bases[CPUCLOCK_PROF].nextevt = softns;
+	}
+
+	if (expiry_cache_is_inactive(pct))
+		stop_process_timers(sig);
+
+	pct->expiry_active = false;
+}
+
+/*
+ * This is called from the signal code (via posixtimer_rearm)
+ * when the last timer signal was delivered and we have to reload the timer.
+ */
+static void posix_cpu_timer_rearm(struct k_itimer *timer)
+{
+	clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
+	struct task_struct *p;
+	struct sighand_struct *sighand;
+	unsigned long flags;
+	u64 now;
+
+	rcu_read_lock();
+	p = cpu_timer_task_rcu(timer);
+	if (!p)
+		goto out;
+
+	/* Protect timer list r/w in arm_timer() */
+	sighand = lock_task_sighand(p, &flags);
+	if (unlikely(sighand == NULL))
+		goto out;
+
+	/*
+	 * Fetch the current sample and update the timer's expiry time.
+	 */
+	if (CPUCLOCK_PERTHREAD(timer->it_clock))
+		now = cpu_clock_sample(clkid, p);
+	else
+		now = cpu_clock_sample_group(clkid, p, true);
+
+	bump_cpu_timer(timer, now);
+
+	/*
+	 * Now re-arm for the new expiry time.
+	 */
+	arm_timer(timer, p);
+	unlock_task_sighand(p, &flags);
+out:
+	rcu_read_unlock();
+}
+
+/**
+ * task_cputimers_expired - Check whether posix CPU timers are expired
+ *
+ * @samples:	Array of current samples for the CPUCLOCK clocks
+ * @pct:	Pointer to a posix_cputimers container
+ *
+ * Returns true if any member of @samples is greater than the corresponding
+ * member of @pct->bases[CLK].nextevt. False otherwise
+ */
+static inline bool
+task_cputimers_expired(const u64 *samples, struct posix_cputimers *pct)
+{
+	int i;
+
+	for (i = 0; i < CPUCLOCK_MAX; i++) {
+		if (samples[i] >= pct->bases[i].nextevt)
+			return true;
+	}
+	return false;
+}
+
+/**
+ * fastpath_timer_check - POSIX CPU timers fast path.
+ *
+ * @tsk:	The task (thread) being checked.
+ *
+ * Check the task and thread group timers.  If both are zero (there are no
+ * timers set) return false.  Otherwise snapshot the task and thread group
+ * timers and compare them with the corresponding expiration times.  Return
+ * true if a timer has expired, else return false.
+ */
+static inline bool fastpath_timer_check(struct task_struct *tsk)
+{
+	struct posix_cputimers *pct = &tsk->posix_cputimers;
+	struct signal_struct *sig;
+
+	if (!expiry_cache_is_inactive(pct)) {
+		u64 samples[CPUCLOCK_MAX];
+
+		task_sample_cputime(tsk, samples);
+		if (task_cputimers_expired(samples, pct))
+			return true;
+	}
+
+	sig = tsk->signal;
+	pct = &sig->posix_cputimers;
+	/*
+	 * Check if thread group timers expired when timers are active and
+	 * no other thread in the group is already handling expiry for
+	 * thread group cputimers. These fields are read without the
+	 * sighand lock. However, this is fine because this is meant to be
+	 * a fastpath heuristic to determine whether we should try to
+	 * acquire the sighand lock to handle timer expiry.
+	 *
+	 * In the worst case scenario, if concurrently timers_active is set
+	 * or expiry_active is cleared, but the current thread doesn't see
+	 * the change yet, the timer checks are delayed until the next
+	 * thread in the group gets a scheduler interrupt to handle the
+	 * timer. This isn't an issue in practice because these types of
+	 * delays with signals actually getting sent are expected.
+	 */
+	if (READ_ONCE(pct->timers_active) && !READ_ONCE(pct->expiry_active)) {
+		u64 samples[CPUCLOCK_MAX];
+
+		proc_sample_cputime_atomic(&sig->cputimer.cputime_atomic,
+					   samples);
+
+		if (task_cputimers_expired(samples, pct))
+			return true;
+	}
+
+	if (dl_task(tsk) && tsk->dl.dl_overrun)
+		return true;
+
+	return false;
+}
+
+static void handle_posix_cpu_timers(struct task_struct *tsk);
+
+#ifdef CONFIG_POSIX_CPU_TIMERS_TASK_WORK
+static void posix_cpu_timers_work(struct callback_head *work)
+{
+	struct posix_cputimers_work *cw = container_of(work, typeof(*cw), work);
+
+	mutex_lock(&cw->mutex);
+	handle_posix_cpu_timers(current);
+	mutex_unlock(&cw->mutex);
+}
+
+/*
+ * Invoked from the posix-timer core when a cancel operation failed because
+ * the timer is marked firing. The caller holds rcu_read_lock(), which
+ * protects the timer and the task which is expiring it from being freed.
+ */
+static void posix_cpu_timer_wait_running(struct k_itimer *timr)
+{
+	struct task_struct *tsk = rcu_dereference(timr->it.cpu.handling);
+
+	/* Has the handling task completed expiry already? */
+	if (!tsk)
+		return;
+
+	/* Ensure that the task cannot go away */
+	get_task_struct(tsk);
+	/* Now drop the RCU protection so the mutex can be locked */
+	rcu_read_unlock();
+	/* Wait on the expiry mutex */
+	mutex_lock(&tsk->posix_cputimers_work.mutex);
+	/* Release it immediately again. */
+	mutex_unlock(&tsk->posix_cputimers_work.mutex);
+	/* Drop the task reference. */
+	put_task_struct(tsk);
+	/* Relock RCU so the callsite is balanced */
+	rcu_read_lock();
+}
+
+static void posix_cpu_timer_wait_running_nsleep(struct k_itimer *timr)
+{
+	/* Ensure that timr->it.cpu.handling task cannot go away */
+	rcu_read_lock();
+	spin_unlock_irq(&timr->it_lock);
+	posix_cpu_timer_wait_running(timr);
+	rcu_read_unlock();
+	/* @timr is on stack and is valid */
+	spin_lock_irq(&timr->it_lock);
+}
+
+/*
+ * Clear existing posix CPU timers task work.
+ */
+void clear_posix_cputimers_work(struct task_struct *p)
+{
+	/*
+	 * A copied work entry from the old task is not meaningful, clear it.
+	 * N.B. init_task_work will not do this.
+	 */
+	memset(&p->posix_cputimers_work.work, 0,
+	       sizeof(p->posix_cputimers_work.work));
+	init_task_work(&p->posix_cputimers_work.work,
+		       posix_cpu_timers_work);
+	mutex_init(&p->posix_cputimers_work.mutex);
+	p->posix_cputimers_work.scheduled = false;
+}
+
+/*
+ * Initialize posix CPU timers task work in init task. Out of line to
+ * keep the callback static and to avoid header recursion hell.
+ */
+void __init posix_cputimers_init_work(void)
+{
+	clear_posix_cputimers_work(current);
+}
+
+/*
+ * Note: All operations on tsk->posix_cputimer_work.scheduled happen either
+ * in hard interrupt context or in task context with interrupts
+ * disabled. Aside of that the writer/reader interaction is always in the
+ * context of the current task, which means they are strict per CPU.
+ */
+static inline bool posix_cpu_timers_work_scheduled(struct task_struct *tsk)
+{
+	return tsk->posix_cputimers_work.scheduled;
+}
+
+static inline void __run_posix_cpu_timers(struct task_struct *tsk)
+{
+	if (WARN_ON_ONCE(tsk->posix_cputimers_work.scheduled))
+		return;
+
+	/* Schedule task work to actually expire the timers */
+	tsk->posix_cputimers_work.scheduled = true;
+	task_work_add(tsk, &tsk->posix_cputimers_work.work, TWA_RESUME);
+}
+
+static inline bool posix_cpu_timers_enable_work(struct task_struct *tsk,
+						unsigned long start)
+{
+	bool ret = true;
+
+	/*
+	 * On !RT kernels interrupts are disabled while collecting expired
+	 * timers, so no tick can happen and the fast path check can be
+	 * reenabled without further checks.
+	 */
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {
+		tsk->posix_cputimers_work.scheduled = false;
+		return true;
+	}
+
+	/*
+	 * On RT enabled kernels ticks can happen while the expired timers
+	 * are collected under sighand lock. But any tick which observes
+	 * the CPUTIMERS_WORK_SCHEDULED bit set, does not run the fastpath
+	 * checks. So reenabling the tick work has do be done carefully:
+	 *
+	 * Disable interrupts and run the fast path check if jiffies have
+	 * advanced since the collecting of expired timers started. If
+	 * jiffies have not advanced or the fast path check did not find
+	 * newly expired timers, reenable the fast path check in the timer
+	 * interrupt. If there are newly expired timers, return false and
+	 * let the collection loop repeat.
+	 */
+	local_irq_disable();
+	if (start != jiffies && fastpath_timer_check(tsk))
+		ret = false;
+	else
+		tsk->posix_cputimers_work.scheduled = false;
+	local_irq_enable();
+
+	return ret;
+}
+#else /* CONFIG_POSIX_CPU_TIMERS_TASK_WORK */
+static inline void __run_posix_cpu_timers(struct task_struct *tsk)
+{
+	lockdep_posixtimer_enter();
+	handle_posix_cpu_timers(tsk);
+	lockdep_posixtimer_exit();
+}
+
+static void posix_cpu_timer_wait_running(struct k_itimer *timr)
+{
+	cpu_relax();
+}
+
+static void posix_cpu_timer_wait_running_nsleep(struct k_itimer *timr)
+{
+	spin_unlock_irq(&timr->it_lock);
+	cpu_relax();
+	spin_lock_irq(&timr->it_lock);
+}
+
+static inline bool posix_cpu_timers_work_scheduled(struct task_struct *tsk)
+{
+	return false;
+}
+
+static inline bool posix_cpu_timers_enable_work(struct task_struct *tsk,
+						unsigned long start)
+{
+	return true;
+}
+#endif /* CONFIG_POSIX_CPU_TIMERS_TASK_WORK */
+
+static void handle_posix_cpu_timers(struct task_struct *tsk)
+{
+	struct k_itimer *timer, *next;
+	unsigned long flags, start;
+	LIST_HEAD(firing);
+
+	if (!lock_task_sighand(tsk, &flags))
+		return;
+
+	do {
+		/*
+		 * On RT locking sighand lock does not disable interrupts,
+		 * so this needs to be careful vs. ticks. Store the current
+		 * jiffies value.
+		 */
+		start = READ_ONCE(jiffies);
+		barrier();
+
+		/*
+		 * Here we take off tsk->signal->cpu_timers[N] and
+		 * tsk->cpu_timers[N] all the timers that are firing, and
+		 * put them on the firing list.
+		 */
+		check_thread_timers(tsk, &firing);
+
+		check_process_timers(tsk, &firing);
+
+		/*
+		 * The above timer checks have updated the expiry cache and
+		 * because nothing can have queued or modified timers after
+		 * sighand lock was taken above it is guaranteed to be
+		 * consistent. So the next timer interrupt fastpath check
+		 * will find valid data.
+		 *
+		 * If timer expiry runs in the timer interrupt context then
+		 * the loop is not relevant as timers will be directly
+		 * expired in interrupt context. The stub function below
+		 * returns always true which allows the compiler to
+		 * optimize the loop out.
+		 *
+		 * If timer expiry is deferred to task work context then
+		 * the following rules apply:
+		 *
+		 * - On !RT kernels no tick can have happened on this CPU
+		 *   after sighand lock was acquired because interrupts are
+		 *   disabled. So reenabling task work before dropping
+		 *   sighand lock and reenabling interrupts is race free.
+		 *
+		 * - On RT kernels ticks might have happened but the tick
+		 *   work ignored posix CPU timer handling because the
+		 *   CPUTIMERS_WORK_SCHEDULED bit is set. Reenabling work
+		 *   must be done very carefully including a check whether
+		 *   ticks have happened since the start of the timer
+		 *   expiry checks. posix_cpu_timers_enable_work() takes
+		 *   care of that and eventually lets the expiry checks
+		 *   run again.
+		 */
+	} while (!posix_cpu_timers_enable_work(tsk, start));
+
+	/*
+	 * We must release sighand lock before taking any timer's lock.
+	 * There is a potential race with timer deletion here, as the
+	 * siglock now protects our private firing list.  We have set
+	 * the firing flag in each timer, so that a deletion attempt
+	 * that gets the timer lock before we do will give it up and
+	 * spin until we've taken care of that timer below.
+	 */
+	unlock_task_sighand(tsk, &flags);
+
+	/*
+	 * Now that all the timers on our list have the firing flag,
+	 * no one will touch their list entries but us.  We'll take
+	 * each timer's lock before clearing its firing flag, so no
+	 * timer call will interfere.
+	 */
+	list_for_each_entry_safe(timer, next, &firing, it.cpu.elist) {
+		int cpu_firing;
+
+		/*
+		 * spin_lock() is sufficient here even independent of the
+		 * expiry context. If expiry happens in hard interrupt
+		 * context it's obvious. For task work context it's safe
+		 * because all other operations on timer::it_lock happen in
+		 * task context (syscall or exit).
+		 */
+		spin_lock(&timer->it_lock);
+		list_del_init(&timer->it.cpu.elist);
+		cpu_firing = timer->it.cpu.firing;
+		timer->it.cpu.firing = 0;
+		/*
+		 * The firing flag is -1 if we collided with a reset
+		 * of the timer, which already reported this
+		 * almost-firing as an overrun.  So don't generate an event.
+		 */
+		if (likely(cpu_firing >= 0))
+			cpu_timer_fire(timer);
+		/* See posix_cpu_timer_wait_running() */
+		rcu_assign_pointer(timer->it.cpu.handling, NULL);
+		spin_unlock(&timer->it_lock);
+	}
+}
+
+/*
+ * This is called from the timer interrupt handler.  The irq handler has
+ * already updated our counts.  We need to check if any timers fire now.
+ * Interrupts are disabled.
+ */
+void run_posix_cpu_timers(void)
+{
+	struct task_struct *tsk = current;
+
+	lockdep_assert_irqs_disabled();
+
+	/*
+	 * If the actual expiry is deferred to task work context and the
+	 * work is already scheduled there is no point to do anything here.
+	 */
+	if (posix_cpu_timers_work_scheduled(tsk))
+		return;
+
+	/*
+	 * The fast path checks that there are no expired thread or thread
+	 * group timers.  If that's so, just return.
+	 */
+	if (!fastpath_timer_check(tsk))
+		return;
+
+	__run_posix_cpu_timers(tsk);
+}
+
+/*
+ * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
+ * The tsk->sighand->siglock must be held by the caller.
+ */
+void set_process_cpu_timer(struct task_struct *tsk, unsigned int clkid,
+			   u64 *newval, u64 *oldval)
+{
+	u64 now, *nextevt;
+
+	if (WARN_ON_ONCE(clkid >= CPUCLOCK_SCHED))
+		return;
+
+	nextevt = &tsk->signal->posix_cputimers.bases[clkid].nextevt;
+	now = cpu_clock_sample_group(clkid, tsk, true);
+
+	if (oldval) {
+		/*
+		 * We are setting itimer. The *oldval is absolute and we update
+		 * it to be relative, *newval argument is relative and we update
+		 * it to be absolute.
+		 */
+		if (*oldval) {
+			if (*oldval <= now) {
+				/* Just about to fire. */
+				*oldval = TICK_NSEC;
+			} else {
+				*oldval -= now;
+			}
+		}
+
+		if (*newval)
+			*newval += now;
+	}
+
+	/*
+	 * Update expiration cache if this is the earliest timer. CPUCLOCK_PROF
+	 * expiry cache is also used by RLIMIT_CPU!.
+	 */
+	if (*newval < *nextevt)
+		*nextevt = *newval;
+
+	tick_dep_set_signal(tsk, TICK_DEP_BIT_POSIX_TIMER);
+}
+
+static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
+			    const struct timespec64 *rqtp)
+{
+	struct itimerspec64 it;
+	struct k_itimer timer;
+	u64 expires;
+	int error;
+
+	/*
+	 * Set up a temporary timer and then wait for it to go off.
+	 */
+	memset(&timer, 0, sizeof timer);
+	spin_lock_init(&timer.it_lock);
+	timer.it_clock = which_clock;
+	timer.it_overrun = -1;
+	error = posix_cpu_timer_create(&timer);
+	timer.it_process = current;
+
+	if (!error) {
+		static struct itimerspec64 zero_it;
+		struct restart_block *restart;
+
+		memset(&it, 0, sizeof(it));
+		it.it_value = *rqtp;
+
+		spin_lock_irq(&timer.it_lock);
+		error = posix_cpu_timer_set(&timer, flags, &it, NULL);
+		if (error) {
+			spin_unlock_irq(&timer.it_lock);
+			return error;
+		}
+
+		while (!signal_pending(current)) {
+			if (!cpu_timer_getexpires(&timer.it.cpu)) {
+				/*
+				 * Our timer fired and was reset, below
+				 * deletion can not fail.
+				 */
+				posix_cpu_timer_del(&timer);
+				spin_unlock_irq(&timer.it_lock);
+				return 0;
+			}
+
+			/*
+			 * Block until cpu_timer_fire (or a signal) wakes us.
+			 */
+			__set_current_state(TASK_INTERRUPTIBLE);
+			spin_unlock_irq(&timer.it_lock);
+			schedule();
+			spin_lock_irq(&timer.it_lock);
+		}
+
+		/*
+		 * We were interrupted by a signal.
+		 */
+		expires = cpu_timer_getexpires(&timer.it.cpu);
+		error = posix_cpu_timer_set(&timer, 0, &zero_it, &it);
+		if (!error) {
+			/* Timer is now unarmed, deletion can not fail. */
+			posix_cpu_timer_del(&timer);
+		} else {
+			while (error == TIMER_RETRY) {
+				posix_cpu_timer_wait_running_nsleep(&timer);
+				error = posix_cpu_timer_del(&timer);
+			}
+		}
+
+		spin_unlock_irq(&timer.it_lock);
+
+		if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
+			/*
+			 * It actually did fire already.
+			 */
+			return 0;
+		}
+
+		error = -ERESTART_RESTARTBLOCK;
+		/*
+		 * Report back to the user the time still remaining.
+		 */
+		restart = &current->restart_block;
+		restart->nanosleep.expires = expires;
+		if (restart->nanosleep.type != TT_NONE)
+			error = nanosleep_copyout(restart, &it.it_value);
+	}
+
+	return error;
+}
+
+static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
+
+static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
+			    const struct timespec64 *rqtp)
+{
+	struct restart_block *restart_block = &current->restart_block;
+	int error;
+
+	/*
+	 * Diagnose required errors first.
+	 */
+	if (CPUCLOCK_PERTHREAD(which_clock) &&
+	    (CPUCLOCK_PID(which_clock) == 0 ||
+	     CPUCLOCK_PID(which_clock) == task_pid_vnr(current)))
+		return -EINVAL;
+
+	error = do_cpu_nanosleep(which_clock, flags, rqtp);
+
+	if (error == -ERESTART_RESTARTBLOCK) {
+
+		if (flags & TIMER_ABSTIME)
+			return -ERESTARTNOHAND;
+
+		restart_block->nanosleep.clockid = which_clock;
+		set_restart_fn(restart_block, posix_cpu_nsleep_restart);
+	}
+	return error;
+}
+
+static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
+{
+	clockid_t which_clock = restart_block->nanosleep.clockid;
+	struct timespec64 t;
+
+	t = ns_to_timespec64(restart_block->nanosleep.expires);
+
+	return do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t);
+}
+
+#define PROCESS_CLOCK	make_process_cpuclock(0, CPUCLOCK_SCHED)
+#define THREAD_CLOCK	make_thread_cpuclock(0, CPUCLOCK_SCHED)
+
+static int process_cpu_clock_getres(const clockid_t which_clock,
+				    struct timespec64 *tp)
+{
+	return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
+}
+static int process_cpu_clock_get(const clockid_t which_clock,
+				 struct timespec64 *tp)
+{
+	return posix_cpu_clock_get(PROCESS_CLOCK, tp);
+}
+static int process_cpu_timer_create(struct k_itimer *timer)
+{
+	timer->it_clock = PROCESS_CLOCK;
+	return posix_cpu_timer_create(timer);
+}
+static int process_cpu_nsleep(const clockid_t which_clock, int flags,
+			      const struct timespec64 *rqtp)
+{
+	return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp);
+}
+static int thread_cpu_clock_getres(const clockid_t which_clock,
+				   struct timespec64 *tp)
+{
+	return posix_cpu_clock_getres(THREAD_CLOCK, tp);
+}
+static int thread_cpu_clock_get(const clockid_t which_clock,
+				struct timespec64 *tp)
+{
+	return posix_cpu_clock_get(THREAD_CLOCK, tp);
+}
+static int thread_cpu_timer_create(struct k_itimer *timer)
+{
+	timer->it_clock = THREAD_CLOCK;
+	return posix_cpu_timer_create(timer);
+}
+
+const struct k_clock clock_posix_cpu = {
+	.clock_getres		= posix_cpu_clock_getres,
+	.clock_set		= posix_cpu_clock_set,
+	.clock_get_timespec	= posix_cpu_clock_get,
+	.timer_create		= posix_cpu_timer_create,
+	.nsleep			= posix_cpu_nsleep,
+	.timer_set		= posix_cpu_timer_set,
+	.timer_del		= posix_cpu_timer_del,
+	.timer_get		= posix_cpu_timer_get,
+	.timer_rearm		= posix_cpu_timer_rearm,
+	.timer_wait_running	= posix_cpu_timer_wait_running,
+};
+
+const struct k_clock clock_process = {
+	.clock_getres		= process_cpu_clock_getres,
+	.clock_get_timespec	= process_cpu_clock_get,
+	.timer_create		= process_cpu_timer_create,
+	.nsleep			= process_cpu_nsleep,
+};
+
+const struct k_clock clock_thread = {
+	.clock_getres		= thread_cpu_clock_getres,
+	.clock_get_timespec	= thread_cpu_clock_get,
+	.timer_create		= thread_cpu_timer_create,
+};
diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
new file mode 100644
index 000000000..828aeecbd
--- /dev/null
+++ b/kernel/time/posix-stubs.c
@@ -0,0 +1,254 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Dummy stubs used when CONFIG_POSIX_TIMERS=n
+ *
+ * Created by:  Nicolas Pitre, July 2016
+ * Copyright:   (C) 2016 Linaro Limited
+ */
+
+#include <linux/linkage.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/syscalls.h>
+#include <linux/ktime.h>
+#include <linux/timekeeping.h>
+#include <linux/posix-timers.h>
+#include <linux/time_namespace.h>
+#include <linux/compat.h>
+
+#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
+/* Architectures may override SYS_NI and COMPAT_SYS_NI */
+#include <asm/syscall_wrapper.h>
+#endif
+
+asmlinkage long sys_ni_posix_timers(void)
+{
+	pr_err_once("process %d (%s) attempted a POSIX timer syscall "
+		    "while CONFIG_POSIX_TIMERS is not set\n",
+		    current->pid, current->comm);
+	return -ENOSYS;
+}
+
+#ifndef SYS_NI
+#define SYS_NI(name)  SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers)
+#endif
+
+#ifndef COMPAT_SYS_NI
+#define COMPAT_SYS_NI(name)  SYSCALL_ALIAS(compat_sys_##name, sys_ni_posix_timers)
+#endif
+
+SYS_NI(timer_create);
+SYS_NI(timer_gettime);
+SYS_NI(timer_getoverrun);
+SYS_NI(timer_settime);
+SYS_NI(timer_delete);
+SYS_NI(clock_adjtime);
+SYS_NI(getitimer);
+SYS_NI(setitimer);
+SYS_NI(clock_adjtime32);
+#ifdef __ARCH_WANT_SYS_ALARM
+SYS_NI(alarm);
+#endif
+
+/*
+ * We preserve minimal support for CLOCK_REALTIME and CLOCK_MONOTONIC
+ * as it is easy to remain compatible with little code. CLOCK_BOOTTIME
+ * is also included for convenience as at least systemd uses it.
+ */
+
+SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
+		const struct __kernel_timespec __user *, tp)
+{
+	struct timespec64 new_tp;
+
+	if (which_clock != CLOCK_REALTIME)
+		return -EINVAL;
+	if (get_timespec64(&new_tp, tp))
+		return -EFAULT;
+
+	return do_sys_settimeofday64(&new_tp, NULL);
+}
+
+static int do_clock_gettime(clockid_t which_clock, struct timespec64 *tp)
+{
+	switch (which_clock) {
+	case CLOCK_REALTIME:
+		ktime_get_real_ts64(tp);
+		break;
+	case CLOCK_MONOTONIC:
+		ktime_get_ts64(tp);
+		timens_add_monotonic(tp);
+		break;
+	case CLOCK_BOOTTIME:
+		ktime_get_boottime_ts64(tp);
+		timens_add_boottime(tp);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
+		struct __kernel_timespec __user *, tp)
+{
+	int ret;
+	struct timespec64 kernel_tp;
+
+	ret = do_clock_gettime(which_clock, &kernel_tp);
+	if (ret)
+		return ret;
+
+	if (put_timespec64(&kernel_tp, tp))
+		return -EFAULT;
+	return 0;
+}
+
+SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, struct __kernel_timespec __user *, tp)
+{
+	struct timespec64 rtn_tp = {
+		.tv_sec = 0,
+		.tv_nsec = hrtimer_resolution,
+	};
+
+	switch (which_clock) {
+	case CLOCK_REALTIME:
+	case CLOCK_MONOTONIC:
+	case CLOCK_BOOTTIME:
+		if (put_timespec64(&rtn_tp, tp))
+			return -EFAULT;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
+		const struct __kernel_timespec __user *, rqtp,
+		struct __kernel_timespec __user *, rmtp)
+{
+	struct timespec64 t;
+	ktime_t texp;
+
+	switch (which_clock) {
+	case CLOCK_REALTIME:
+	case CLOCK_MONOTONIC:
+	case CLOCK_BOOTTIME:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (get_timespec64(&t, rqtp))
+		return -EFAULT;
+	if (!timespec64_valid(&t))
+		return -EINVAL;
+	if (flags & TIMER_ABSTIME)
+		rmtp = NULL;
+	current->restart_block.fn = do_no_restart_syscall;
+	current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
+	current->restart_block.nanosleep.rmtp = rmtp;
+	texp = timespec64_to_ktime(t);
+	if (flags & TIMER_ABSTIME)
+		texp = timens_ktime_to_host(which_clock, texp);
+	return hrtimer_nanosleep(texp, flags & TIMER_ABSTIME ?
+				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
+				 which_clock);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYS_NI(timer_create);
+#endif
+
+#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA)
+COMPAT_SYS_NI(getitimer);
+COMPAT_SYS_NI(setitimer);
+#endif
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+SYS_NI(timer_settime32);
+SYS_NI(timer_gettime32);
+
+SYSCALL_DEFINE2(clock_settime32, const clockid_t, which_clock,
+		struct old_timespec32 __user *, tp)
+{
+	struct timespec64 new_tp;
+
+	if (which_clock != CLOCK_REALTIME)
+		return -EINVAL;
+	if (get_old_timespec32(&new_tp, tp))
+		return -EFAULT;
+
+	return do_sys_settimeofday64(&new_tp, NULL);
+}
+
+SYSCALL_DEFINE2(clock_gettime32, clockid_t, which_clock,
+		struct old_timespec32 __user *, tp)
+{
+	int ret;
+	struct timespec64 kernel_tp;
+
+	ret = do_clock_gettime(which_clock, &kernel_tp);
+	if (ret)
+		return ret;
+
+	if (put_old_timespec32(&kernel_tp, tp))
+		return -EFAULT;
+	return 0;
+}
+
+SYSCALL_DEFINE2(clock_getres_time32, clockid_t, which_clock,
+		struct old_timespec32 __user *, tp)
+{
+	struct timespec64 rtn_tp = {
+		.tv_sec = 0,
+		.tv_nsec = hrtimer_resolution,
+	};
+
+	switch (which_clock) {
+	case CLOCK_REALTIME:
+	case CLOCK_MONOTONIC:
+	case CLOCK_BOOTTIME:
+		if (put_old_timespec32(&rtn_tp, tp))
+			return -EFAULT;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+SYSCALL_DEFINE4(clock_nanosleep_time32, clockid_t, which_clock, int, flags,
+		struct old_timespec32 __user *, rqtp,
+		struct old_timespec32 __user *, rmtp)
+{
+	struct timespec64 t;
+	ktime_t texp;
+
+	switch (which_clock) {
+	case CLOCK_REALTIME:
+	case CLOCK_MONOTONIC:
+	case CLOCK_BOOTTIME:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (get_old_timespec32(&t, rqtp))
+		return -EFAULT;
+	if (!timespec64_valid(&t))
+		return -EINVAL;
+	if (flags & TIMER_ABSTIME)
+		rmtp = NULL;
+	current->restart_block.fn = do_no_restart_syscall;
+	current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
+	current->restart_block.nanosleep.compat_rmtp = rmtp;
+	texp = timespec64_to_ktime(t);
+	if (flags & TIMER_ABSTIME)
+		texp = timens_ktime_to_host(which_clock, texp);
+	return hrtimer_nanosleep(texp, flags & TIMER_ABSTIME ?
+				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
+				 which_clock);
+}
+#endif
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
new file mode 100644
index 000000000..ed3c4a954
--- /dev/null
+++ b/kernel/time/posix-timers.c
@@ -0,0 +1,1453 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * 2002-10-15  Posix Clocks & timers
+ *                           by George Anzinger george@mvista.com
+ *			     Copyright (C) 2002 2003 by MontaVista Software.
+ *
+ * 2004-06-01  Fix CLOCK_REALTIME clock/timer TIMER_ABSTIME bug.
+ *			     Copyright (C) 2004 Boris Hu
+ *
+ * These are all the functions necessary to implement POSIX clocks & timers
+ */
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/mutex.h>
+#include <linux/sched/task.h>
+
+#include <linux/uaccess.h>
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/compiler.h>
+#include <linux/hash.h>
+#include <linux/posix-clock.h>
+#include <linux/posix-timers.h>
+#include <linux/syscalls.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+#include <linux/export.h>
+#include <linux/hashtable.h>
+#include <linux/compat.h>
+#include <linux/nospec.h>
+#include <linux/time_namespace.h>
+
+#include "timekeeping.h"
+#include "posix-timers.h"
+
+/*
+ * Management arrays for POSIX timers. Timers are now kept in static hash table
+ * with 512 entries.
+ * Timer ids are allocated by local routine, which selects proper hash head by
+ * key, constructed from current->signal address and per signal struct counter.
+ * This keeps timer ids unique per process, but now they can intersect between
+ * processes.
+ */
+
+/*
+ * Lets keep our timers in a slab cache :-)
+ */
+static struct kmem_cache *posix_timers_cache;
+
+static DEFINE_HASHTABLE(posix_timers_hashtable, 9);
+static DEFINE_SPINLOCK(hash_lock);
+
+static const struct k_clock * const posix_clocks[];
+static const struct k_clock *clockid_to_kclock(const clockid_t id);
+static const struct k_clock clock_realtime, clock_monotonic;
+
+/*
+ * we assume that the new SIGEV_THREAD_ID shares no bits with the other
+ * SIGEV values.  Here we put out an error if this assumption fails.
+ */
+#if SIGEV_THREAD_ID != (SIGEV_THREAD_ID & \
+                       ~(SIGEV_SIGNAL | SIGEV_NONE | SIGEV_THREAD))
+#error "SIGEV_THREAD_ID must not share bit with other SIGEV values!"
+#endif
+
+/*
+ * The timer ID is turned into a timer address by idr_find().
+ * Verifying a valid ID consists of:
+ *
+ * a) checking that idr_find() returns other than -1.
+ * b) checking that the timer id matches the one in the timer itself.
+ * c) that the timer owner is in the callers thread group.
+ */
+
+/*
+ * CLOCKs: The POSIX standard calls for a couple of clocks and allows us
+ *	    to implement others.  This structure defines the various
+ *	    clocks.
+ *
+ * RESOLUTION: Clock resolution is used to round up timer and interval
+ *	    times, NOT to report clock times, which are reported with as
+ *	    much resolution as the system can muster.  In some cases this
+ *	    resolution may depend on the underlying clock hardware and
+ *	    may not be quantifiable until run time, and only then is the
+ *	    necessary code is written.	The standard says we should say
+ *	    something about this issue in the documentation...
+ *
+ * FUNCTIONS: The CLOCKs structure defines possible functions to
+ *	    handle various clock functions.
+ *
+ *	    The standard POSIX timer management code assumes the
+ *	    following: 1.) The k_itimer struct (sched.h) is used for
+ *	    the timer.  2.) The list, it_lock, it_clock, it_id and
+ *	    it_pid fields are not modified by timer code.
+ *
+ * Permissions: It is assumed that the clock_settime() function defined
+ *	    for each clock will take care of permission checks.	 Some
+ *	    clocks may be set able by any user (i.e. local process
+ *	    clocks) others not.	 Currently the only set able clock we
+ *	    have is CLOCK_REALTIME and its high res counter part, both of
+ *	    which we beg off on and pass to do_sys_settimeofday().
+ */
+static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags);
+
+#define lock_timer(tid, flags)						   \
+({	struct k_itimer *__timr;					   \
+	__cond_lock(&__timr->it_lock, __timr = __lock_timer(tid, flags));  \
+	__timr;								   \
+})
+
+static int hash(struct signal_struct *sig, unsigned int nr)
+{
+	return hash_32(hash32_ptr(sig) ^ nr, HASH_BITS(posix_timers_hashtable));
+}
+
+static struct k_itimer *__posix_timers_find(struct hlist_head *head,
+					    struct signal_struct *sig,
+					    timer_t id)
+{
+	struct k_itimer *timer;
+
+	hlist_for_each_entry_rcu(timer, head, t_hash,
+				 lockdep_is_held(&hash_lock)) {
+		if ((timer->it_signal == sig) && (timer->it_id == id))
+			return timer;
+	}
+	return NULL;
+}
+
+static struct k_itimer *posix_timer_by_id(timer_t id)
+{
+	struct signal_struct *sig = current->signal;
+	struct hlist_head *head = &posix_timers_hashtable[hash(sig, id)];
+
+	return __posix_timers_find(head, sig, id);
+}
+
+static int posix_timer_add(struct k_itimer *timer)
+{
+	struct signal_struct *sig = current->signal;
+	int first_free_id = sig->posix_timer_id;
+	struct hlist_head *head;
+	int ret = -ENOENT;
+
+	do {
+		spin_lock(&hash_lock);
+		head = &posix_timers_hashtable[hash(sig, sig->posix_timer_id)];
+		if (!__posix_timers_find(head, sig, sig->posix_timer_id)) {
+			hlist_add_head_rcu(&timer->t_hash, head);
+			ret = sig->posix_timer_id;
+		}
+		if (++sig->posix_timer_id < 0)
+			sig->posix_timer_id = 0;
+		if ((sig->posix_timer_id == first_free_id) && (ret == -ENOENT))
+			/* Loop over all possible ids completed */
+			ret = -EAGAIN;
+		spin_unlock(&hash_lock);
+	} while (ret == -ENOENT);
+	return ret;
+}
+
+static inline void unlock_timer(struct k_itimer *timr, unsigned long flags)
+{
+	spin_unlock_irqrestore(&timr->it_lock, flags);
+}
+
+/* Get clock_realtime */
+static int posix_get_realtime_timespec(clockid_t which_clock, struct timespec64 *tp)
+{
+	ktime_get_real_ts64(tp);
+	return 0;
+}
+
+static ktime_t posix_get_realtime_ktime(clockid_t which_clock)
+{
+	return ktime_get_real();
+}
+
+/* Set clock_realtime */
+static int posix_clock_realtime_set(const clockid_t which_clock,
+				    const struct timespec64 *tp)
+{
+	return do_sys_settimeofday64(tp, NULL);
+}
+
+static int posix_clock_realtime_adj(const clockid_t which_clock,
+				    struct __kernel_timex *t)
+{
+	return do_adjtimex(t);
+}
+
+/*
+ * Get monotonic time for posix timers
+ */
+static int posix_get_monotonic_timespec(clockid_t which_clock, struct timespec64 *tp)
+{
+	ktime_get_ts64(tp);
+	timens_add_monotonic(tp);
+	return 0;
+}
+
+static ktime_t posix_get_monotonic_ktime(clockid_t which_clock)
+{
+	return ktime_get();
+}
+
+/*
+ * Get monotonic-raw time for posix timers
+ */
+static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec64 *tp)
+{
+	ktime_get_raw_ts64(tp);
+	timens_add_monotonic(tp);
+	return 0;
+}
+
+
+static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec64 *tp)
+{
+	ktime_get_coarse_real_ts64(tp);
+	return 0;
+}
+
+static int posix_get_monotonic_coarse(clockid_t which_clock,
+						struct timespec64 *tp)
+{
+	ktime_get_coarse_ts64(tp);
+	timens_add_monotonic(tp);
+	return 0;
+}
+
+static int posix_get_coarse_res(const clockid_t which_clock, struct timespec64 *tp)
+{
+	*tp = ktime_to_timespec64(KTIME_LOW_RES);
+	return 0;
+}
+
+static int posix_get_boottime_timespec(const clockid_t which_clock, struct timespec64 *tp)
+{
+	ktime_get_boottime_ts64(tp);
+	timens_add_boottime(tp);
+	return 0;
+}
+
+static ktime_t posix_get_boottime_ktime(const clockid_t which_clock)
+{
+	return ktime_get_boottime();
+}
+
+static int posix_get_tai_timespec(clockid_t which_clock, struct timespec64 *tp)
+{
+	ktime_get_clocktai_ts64(tp);
+	return 0;
+}
+
+static ktime_t posix_get_tai_ktime(clockid_t which_clock)
+{
+	return ktime_get_clocktai();
+}
+
+static int posix_get_hrtimer_res(clockid_t which_clock, struct timespec64 *tp)
+{
+	tp->tv_sec = 0;
+	tp->tv_nsec = hrtimer_resolution;
+	return 0;
+}
+
+/*
+ * Initialize everything, well, just everything in Posix clocks/timers ;)
+ */
+static __init int init_posix_timers(void)
+{
+	posix_timers_cache = kmem_cache_create("posix_timers_cache",
+					sizeof(struct k_itimer), 0,
+					SLAB_PANIC | SLAB_ACCOUNT, NULL);
+	return 0;
+}
+__initcall(init_posix_timers);
+
+/*
+ * The siginfo si_overrun field and the return value of timer_getoverrun(2)
+ * are of type int. Clamp the overrun value to INT_MAX
+ */
+static inline int timer_overrun_to_int(struct k_itimer *timr, int baseval)
+{
+	s64 sum = timr->it_overrun_last + (s64)baseval;
+
+	return sum > (s64)INT_MAX ? INT_MAX : (int)sum;
+}
+
+static void common_hrtimer_rearm(struct k_itimer *timr)
+{
+	struct hrtimer *timer = &timr->it.real.timer;
+
+	timr->it_overrun += hrtimer_forward(timer, timer->base->get_time(),
+					    timr->it_interval);
+	hrtimer_restart(timer);
+}
+
+/*
+ * This function is exported for use by the signal deliver code.  It is
+ * called just prior to the info block being released and passes that
+ * block to us.  It's function is to update the overrun entry AND to
+ * restart the timer.  It should only be called if the timer is to be
+ * restarted (i.e. we have flagged this in the sys_private entry of the
+ * info block).
+ *
+ * To protect against the timer going away while the interrupt is queued,
+ * we require that the it_requeue_pending flag be set.
+ */
+void posixtimer_rearm(struct kernel_siginfo *info)
+{
+	struct k_itimer *timr;
+	unsigned long flags;
+
+	timr = lock_timer(info->si_tid, &flags);
+	if (!timr)
+		return;
+
+	if (timr->it_interval && timr->it_requeue_pending == info->si_sys_private) {
+		timr->kclock->timer_rearm(timr);
+
+		timr->it_active = 1;
+		timr->it_overrun_last = timr->it_overrun;
+		timr->it_overrun = -1LL;
+		++timr->it_requeue_pending;
+
+		info->si_overrun = timer_overrun_to_int(timr, info->si_overrun);
+	}
+
+	unlock_timer(timr, flags);
+}
+
+int posix_timer_event(struct k_itimer *timr, int si_private)
+{
+	enum pid_type type;
+	int ret;
+	/*
+	 * FIXME: if ->sigq is queued we can race with
+	 * dequeue_signal()->posixtimer_rearm().
+	 *
+	 * If dequeue_signal() sees the "right" value of
+	 * si_sys_private it calls posixtimer_rearm().
+	 * We re-queue ->sigq and drop ->it_lock().
+	 * posixtimer_rearm() locks the timer
+	 * and re-schedules it while ->sigq is pending.
+	 * Not really bad, but not that we want.
+	 */
+	timr->sigq->info.si_sys_private = si_private;
+
+	type = !(timr->it_sigev_notify & SIGEV_THREAD_ID) ? PIDTYPE_TGID : PIDTYPE_PID;
+	ret = send_sigqueue(timr->sigq, timr->it_pid, type);
+	/* If we failed to send the signal the timer stops. */
+	return ret > 0;
+}
+
+/*
+ * This function gets called when a POSIX.1b interval timer expires.  It
+ * is used as a callback from the kernel internal timer.  The
+ * run_timer_list code ALWAYS calls with interrupts on.
+
+ * This code is for CLOCK_REALTIME* and CLOCK_MONOTONIC* timers.
+ */
+static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
+{
+	struct k_itimer *timr;
+	unsigned long flags;
+	int si_private = 0;
+	enum hrtimer_restart ret = HRTIMER_NORESTART;
+
+	timr = container_of(timer, struct k_itimer, it.real.timer);
+	spin_lock_irqsave(&timr->it_lock, flags);
+
+	timr->it_active = 0;
+	if (timr->it_interval != 0)
+		si_private = ++timr->it_requeue_pending;
+
+	if (posix_timer_event(timr, si_private)) {
+		/*
+		 * signal was not sent because of sig_ignor
+		 * we will not get a call back to restart it AND
+		 * it should be restarted.
+		 */
+		if (timr->it_interval != 0) {
+			ktime_t now = hrtimer_cb_get_time(timer);
+
+			/*
+			 * FIXME: What we really want, is to stop this
+			 * timer completely and restart it in case the
+			 * SIG_IGN is removed. This is a non trivial
+			 * change which involves sighand locking
+			 * (sigh !), which we don't want to do late in
+			 * the release cycle.
+			 *
+			 * For now we just let timers with an interval
+			 * less than a jiffie expire every jiffie to
+			 * avoid softirq starvation in case of SIG_IGN
+			 * and a very small interval, which would put
+			 * the timer right back on the softirq pending
+			 * list. By moving now ahead of time we trick
+			 * hrtimer_forward() to expire the timer
+			 * later, while we still maintain the overrun
+			 * accuracy, but have some inconsistency in
+			 * the timer_gettime() case. This is at least
+			 * better than a starved softirq. A more
+			 * complex fix which solves also another related
+			 * inconsistency is already in the pipeline.
+			 */
+#ifdef CONFIG_HIGH_RES_TIMERS
+			{
+				ktime_t kj = NSEC_PER_SEC / HZ;
+
+				if (timr->it_interval < kj)
+					now = ktime_add(now, kj);
+			}
+#endif
+			timr->it_overrun += hrtimer_forward(timer, now,
+							    timr->it_interval);
+			ret = HRTIMER_RESTART;
+			++timr->it_requeue_pending;
+			timr->it_active = 1;
+		}
+	}
+
+	unlock_timer(timr, flags);
+	return ret;
+}
+
+static struct pid *good_sigevent(sigevent_t * event)
+{
+	struct pid *pid = task_tgid(current);
+	struct task_struct *rtn;
+
+	switch (event->sigev_notify) {
+	case SIGEV_SIGNAL | SIGEV_THREAD_ID:
+		pid = find_vpid(event->sigev_notify_thread_id);
+		rtn = pid_task(pid, PIDTYPE_PID);
+		if (!rtn || !same_thread_group(rtn, current))
+			return NULL;
+		fallthrough;
+	case SIGEV_SIGNAL:
+	case SIGEV_THREAD:
+		if (event->sigev_signo <= 0 || event->sigev_signo > SIGRTMAX)
+			return NULL;
+		fallthrough;
+	case SIGEV_NONE:
+		return pid;
+	default:
+		return NULL;
+	}
+}
+
+static struct k_itimer * alloc_posix_timer(void)
+{
+	struct k_itimer *tmr;
+	tmr = kmem_cache_zalloc(posix_timers_cache, GFP_KERNEL);
+	if (!tmr)
+		return tmr;
+	if (unlikely(!(tmr->sigq = sigqueue_alloc()))) {
+		kmem_cache_free(posix_timers_cache, tmr);
+		return NULL;
+	}
+	clear_siginfo(&tmr->sigq->info);
+	return tmr;
+}
+
+static void k_itimer_rcu_free(struct rcu_head *head)
+{
+	struct k_itimer *tmr = container_of(head, struct k_itimer, rcu);
+
+	kmem_cache_free(posix_timers_cache, tmr);
+}
+
+#define IT_ID_SET	1
+#define IT_ID_NOT_SET	0
+static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
+{
+	if (it_id_set) {
+		unsigned long flags;
+		spin_lock_irqsave(&hash_lock, flags);
+		hlist_del_rcu(&tmr->t_hash);
+		spin_unlock_irqrestore(&hash_lock, flags);
+	}
+	put_pid(tmr->it_pid);
+	sigqueue_free(tmr->sigq);
+	call_rcu(&tmr->rcu, k_itimer_rcu_free);
+}
+
+static int common_timer_create(struct k_itimer *new_timer)
+{
+	hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
+	return 0;
+}
+
+/* Create a POSIX.1b interval timer. */
+static int do_timer_create(clockid_t which_clock, struct sigevent *event,
+			   timer_t __user *created_timer_id)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+	struct k_itimer *new_timer;
+	int error, new_timer_id;
+	int it_id_set = IT_ID_NOT_SET;
+
+	if (!kc)
+		return -EINVAL;
+	if (!kc->timer_create)
+		return -EOPNOTSUPP;
+
+	new_timer = alloc_posix_timer();
+	if (unlikely(!new_timer))
+		return -EAGAIN;
+
+	spin_lock_init(&new_timer->it_lock);
+	new_timer_id = posix_timer_add(new_timer);
+	if (new_timer_id < 0) {
+		error = new_timer_id;
+		goto out;
+	}
+
+	it_id_set = IT_ID_SET;
+	new_timer->it_id = (timer_t) new_timer_id;
+	new_timer->it_clock = which_clock;
+	new_timer->kclock = kc;
+	new_timer->it_overrun = -1LL;
+
+	if (event) {
+		rcu_read_lock();
+		new_timer->it_pid = get_pid(good_sigevent(event));
+		rcu_read_unlock();
+		if (!new_timer->it_pid) {
+			error = -EINVAL;
+			goto out;
+		}
+		new_timer->it_sigev_notify     = event->sigev_notify;
+		new_timer->sigq->info.si_signo = event->sigev_signo;
+		new_timer->sigq->info.si_value = event->sigev_value;
+	} else {
+		new_timer->it_sigev_notify     = SIGEV_SIGNAL;
+		new_timer->sigq->info.si_signo = SIGALRM;
+		memset(&new_timer->sigq->info.si_value, 0, sizeof(sigval_t));
+		new_timer->sigq->info.si_value.sival_int = new_timer->it_id;
+		new_timer->it_pid = get_pid(task_tgid(current));
+	}
+
+	new_timer->sigq->info.si_tid   = new_timer->it_id;
+	new_timer->sigq->info.si_code  = SI_TIMER;
+
+	if (copy_to_user(created_timer_id,
+			 &new_timer_id, sizeof (new_timer_id))) {
+		error = -EFAULT;
+		goto out;
+	}
+
+	error = kc->timer_create(new_timer);
+	if (error)
+		goto out;
+
+	spin_lock_irq(&current->sighand->siglock);
+	new_timer->it_signal = current->signal;
+	list_add(&new_timer->list, &current->signal->posix_timers);
+	spin_unlock_irq(&current->sighand->siglock);
+
+	return 0;
+	/*
+	 * In the case of the timer belonging to another task, after
+	 * the task is unlocked, the timer is owned by the other task
+	 * and may cease to exist at any time.  Don't use or modify
+	 * new_timer after the unlock call.
+	 */
+out:
+	release_posix_timer(new_timer, it_id_set);
+	return error;
+}
+
+SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
+		struct sigevent __user *, timer_event_spec,
+		timer_t __user *, created_timer_id)
+{
+	if (timer_event_spec) {
+		sigevent_t event;
+
+		if (copy_from_user(&event, timer_event_spec, sizeof (event)))
+			return -EFAULT;
+		return do_timer_create(which_clock, &event, created_timer_id);
+	}
+	return do_timer_create(which_clock, NULL, created_timer_id);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE3(timer_create, clockid_t, which_clock,
+		       struct compat_sigevent __user *, timer_event_spec,
+		       timer_t __user *, created_timer_id)
+{
+	if (timer_event_spec) {
+		sigevent_t event;
+
+		if (get_compat_sigevent(&event, timer_event_spec))
+			return -EFAULT;
+		return do_timer_create(which_clock, &event, created_timer_id);
+	}
+	return do_timer_create(which_clock, NULL, created_timer_id);
+}
+#endif
+
+/*
+ * Locking issues: We need to protect the result of the id look up until
+ * we get the timer locked down so it is not deleted under us.  The
+ * removal is done under the idr spinlock so we use that here to bridge
+ * the find to the timer lock.  To avoid a dead lock, the timer id MUST
+ * be release with out holding the timer lock.
+ */
+static struct k_itimer *__lock_timer(timer_t timer_id, unsigned long *flags)
+{
+	struct k_itimer *timr;
+
+	/*
+	 * timer_t could be any type >= int and we want to make sure any
+	 * @timer_id outside positive int range fails lookup.
+	 */
+	if ((unsigned long long)timer_id > INT_MAX)
+		return NULL;
+
+	rcu_read_lock();
+	timr = posix_timer_by_id(timer_id);
+	if (timr) {
+		spin_lock_irqsave(&timr->it_lock, *flags);
+		if (timr->it_signal == current->signal) {
+			rcu_read_unlock();
+			return timr;
+		}
+		spin_unlock_irqrestore(&timr->it_lock, *flags);
+	}
+	rcu_read_unlock();
+
+	return NULL;
+}
+
+static ktime_t common_hrtimer_remaining(struct k_itimer *timr, ktime_t now)
+{
+	struct hrtimer *timer = &timr->it.real.timer;
+
+	return __hrtimer_expires_remaining_adjusted(timer, now);
+}
+
+static s64 common_hrtimer_forward(struct k_itimer *timr, ktime_t now)
+{
+	struct hrtimer *timer = &timr->it.real.timer;
+
+	return hrtimer_forward(timer, now, timr->it_interval);
+}
+
+/*
+ * Get the time remaining on a POSIX.1b interval timer.  This function
+ * is ALWAYS called with spin_lock_irq on the timer, thus it must not
+ * mess with irq.
+ *
+ * We have a couple of messes to clean up here.  First there is the case
+ * of a timer that has a requeue pending.  These timers should appear to
+ * be in the timer list with an expiry as if we were to requeue them
+ * now.
+ *
+ * The second issue is the SIGEV_NONE timer which may be active but is
+ * not really ever put in the timer list (to save system resources).
+ * This timer may be expired, and if so, we will do it here.  Otherwise
+ * it is the same as a requeue pending timer WRT to what we should
+ * report.
+ */
+void common_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting)
+{
+	const struct k_clock *kc = timr->kclock;
+	ktime_t now, remaining, iv;
+	bool sig_none;
+
+	sig_none = timr->it_sigev_notify == SIGEV_NONE;
+	iv = timr->it_interval;
+
+	/* interval timer ? */
+	if (iv) {
+		cur_setting->it_interval = ktime_to_timespec64(iv);
+	} else if (!timr->it_active) {
+		/*
+		 * SIGEV_NONE oneshot timers are never queued. Check them
+		 * below.
+		 */
+		if (!sig_none)
+			return;
+	}
+
+	now = kc->clock_get_ktime(timr->it_clock);
+
+	/*
+	 * When a requeue is pending or this is a SIGEV_NONE timer move the
+	 * expiry time forward by intervals, so expiry is > now.
+	 */
+	if (iv && (timr->it_requeue_pending & REQUEUE_PENDING || sig_none))
+		timr->it_overrun += kc->timer_forward(timr, now);
+
+	remaining = kc->timer_remaining(timr, now);
+	/* Return 0 only, when the timer is expired and not pending */
+	if (remaining <= 0) {
+		/*
+		 * A single shot SIGEV_NONE timer must return 0, when
+		 * it is expired !
+		 */
+		if (!sig_none)
+			cur_setting->it_value.tv_nsec = 1;
+	} else {
+		cur_setting->it_value = ktime_to_timespec64(remaining);
+	}
+}
+
+/* Get the time remaining on a POSIX.1b interval timer. */
+static int do_timer_gettime(timer_t timer_id,  struct itimerspec64 *setting)
+{
+	struct k_itimer *timr;
+	const struct k_clock *kc;
+	unsigned long flags;
+	int ret = 0;
+
+	timr = lock_timer(timer_id, &flags);
+	if (!timr)
+		return -EINVAL;
+
+	memset(setting, 0, sizeof(*setting));
+	kc = timr->kclock;
+	if (WARN_ON_ONCE(!kc || !kc->timer_get))
+		ret = -EINVAL;
+	else
+		kc->timer_get(timr, setting);
+
+	unlock_timer(timr, flags);
+	return ret;
+}
+
+/* Get the time remaining on a POSIX.1b interval timer. */
+SYSCALL_DEFINE2(timer_gettime, timer_t, timer_id,
+		struct __kernel_itimerspec __user *, setting)
+{
+	struct itimerspec64 cur_setting;
+
+	int ret = do_timer_gettime(timer_id, &cur_setting);
+	if (!ret) {
+		if (put_itimerspec64(&cur_setting, setting))
+			ret = -EFAULT;
+	}
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+
+SYSCALL_DEFINE2(timer_gettime32, timer_t, timer_id,
+		struct old_itimerspec32 __user *, setting)
+{
+	struct itimerspec64 cur_setting;
+
+	int ret = do_timer_gettime(timer_id, &cur_setting);
+	if (!ret) {
+		if (put_old_itimerspec32(&cur_setting, setting))
+			ret = -EFAULT;
+	}
+	return ret;
+}
+
+#endif
+
+/*
+ * Get the number of overruns of a POSIX.1b interval timer.  This is to
+ * be the overrun of the timer last delivered.  At the same time we are
+ * accumulating overruns on the next timer.  The overrun is frozen when
+ * the signal is delivered, either at the notify time (if the info block
+ * is not queued) or at the actual delivery time (as we are informed by
+ * the call back to posixtimer_rearm().  So all we need to do is
+ * to pick up the frozen overrun.
+ */
+SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id)
+{
+	struct k_itimer *timr;
+	int overrun;
+	unsigned long flags;
+
+	timr = lock_timer(timer_id, &flags);
+	if (!timr)
+		return -EINVAL;
+
+	overrun = timer_overrun_to_int(timr, 0);
+	unlock_timer(timr, flags);
+
+	return overrun;
+}
+
+static void common_hrtimer_arm(struct k_itimer *timr, ktime_t expires,
+			       bool absolute, bool sigev_none)
+{
+	struct hrtimer *timer = &timr->it.real.timer;
+	enum hrtimer_mode mode;
+
+	mode = absolute ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
+	/*
+	 * Posix magic: Relative CLOCK_REALTIME timers are not affected by
+	 * clock modifications, so they become CLOCK_MONOTONIC based under the
+	 * hood. See hrtimer_init(). Update timr->kclock, so the generic
+	 * functions which use timr->kclock->clock_get_*() work.
+	 *
+	 * Note: it_clock stays unmodified, because the next timer_set() might
+	 * use ABSTIME, so it needs to switch back.
+	 */
+	if (timr->it_clock == CLOCK_REALTIME)
+		timr->kclock = absolute ? &clock_realtime : &clock_monotonic;
+
+	hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
+	timr->it.real.timer.function = posix_timer_fn;
+
+	if (!absolute)
+		expires = ktime_add_safe(expires, timer->base->get_time());
+	hrtimer_set_expires(timer, expires);
+
+	if (!sigev_none)
+		hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
+}
+
+static int common_hrtimer_try_to_cancel(struct k_itimer *timr)
+{
+	return hrtimer_try_to_cancel(&timr->it.real.timer);
+}
+
+static void common_timer_wait_running(struct k_itimer *timer)
+{
+	hrtimer_cancel_wait_running(&timer->it.real.timer);
+}
+
+/*
+ * On PREEMPT_RT this prevent priority inversion against softirq kthread in
+ * case it gets preempted while executing a timer callback. See comments in
+ * hrtimer_cancel_wait_running. For PREEMPT_RT=n this just results in a
+ * cpu_relax().
+ */
+static struct k_itimer *timer_wait_running(struct k_itimer *timer,
+					   unsigned long *flags)
+{
+	const struct k_clock *kc = READ_ONCE(timer->kclock);
+	timer_t timer_id = READ_ONCE(timer->it_id);
+
+	/* Prevent kfree(timer) after dropping the lock */
+	rcu_read_lock();
+	unlock_timer(timer, *flags);
+
+	/*
+	 * kc->timer_wait_running() might drop RCU lock. So @timer
+	 * cannot be touched anymore after the function returns!
+	 */
+	if (!WARN_ON_ONCE(!kc->timer_wait_running))
+		kc->timer_wait_running(timer);
+
+	rcu_read_unlock();
+	/* Relock the timer. It might be not longer hashed. */
+	return lock_timer(timer_id, flags);
+}
+
+/* Set a POSIX.1b interval timer. */
+int common_timer_set(struct k_itimer *timr, int flags,
+		     struct itimerspec64 *new_setting,
+		     struct itimerspec64 *old_setting)
+{
+	const struct k_clock *kc = timr->kclock;
+	bool sigev_none;
+	ktime_t expires;
+
+	if (old_setting)
+		common_timer_get(timr, old_setting);
+
+	/* Prevent rearming by clearing the interval */
+	timr->it_interval = 0;
+	/*
+	 * Careful here. On SMP systems the timer expiry function could be
+	 * active and spinning on timr->it_lock.
+	 */
+	if (kc->timer_try_to_cancel(timr) < 0)
+		return TIMER_RETRY;
+
+	timr->it_active = 0;
+	timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
+		~REQUEUE_PENDING;
+	timr->it_overrun_last = 0;
+
+	/* Switch off the timer when it_value is zero */
+	if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
+		return 0;
+
+	timr->it_interval = timespec64_to_ktime(new_setting->it_interval);
+	expires = timespec64_to_ktime(new_setting->it_value);
+	if (flags & TIMER_ABSTIME)
+		expires = timens_ktime_to_host(timr->it_clock, expires);
+	sigev_none = timr->it_sigev_notify == SIGEV_NONE;
+
+	kc->timer_arm(timr, expires, flags & TIMER_ABSTIME, sigev_none);
+	timr->it_active = !sigev_none;
+	return 0;
+}
+
+static int do_timer_settime(timer_t timer_id, int tmr_flags,
+			    struct itimerspec64 *new_spec64,
+			    struct itimerspec64 *old_spec64)
+{
+	const struct k_clock *kc;
+	struct k_itimer *timr;
+	unsigned long flags;
+	int error = 0;
+
+	if (!timespec64_valid(&new_spec64->it_interval) ||
+	    !timespec64_valid(&new_spec64->it_value))
+		return -EINVAL;
+
+	if (old_spec64)
+		memset(old_spec64, 0, sizeof(*old_spec64));
+
+	timr = lock_timer(timer_id, &flags);
+retry:
+	if (!timr)
+		return -EINVAL;
+
+	kc = timr->kclock;
+	if (WARN_ON_ONCE(!kc || !kc->timer_set))
+		error = -EINVAL;
+	else
+		error = kc->timer_set(timr, tmr_flags, new_spec64, old_spec64);
+
+	if (error == TIMER_RETRY) {
+		// We already got the old time...
+		old_spec64 = NULL;
+		/* Unlocks and relocks the timer if it still exists */
+		timr = timer_wait_running(timr, &flags);
+		goto retry;
+	}
+	unlock_timer(timr, flags);
+
+	return error;
+}
+
+/* Set a POSIX.1b interval timer */
+SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
+		const struct __kernel_itimerspec __user *, new_setting,
+		struct __kernel_itimerspec __user *, old_setting)
+{
+	struct itimerspec64 new_spec, old_spec;
+	struct itimerspec64 *rtn = old_setting ? &old_spec : NULL;
+	int error = 0;
+
+	if (!new_setting)
+		return -EINVAL;
+
+	if (get_itimerspec64(&new_spec, new_setting))
+		return -EFAULT;
+
+	error = do_timer_settime(timer_id, flags, &new_spec, rtn);
+	if (!error && old_setting) {
+		if (put_itimerspec64(&old_spec, old_setting))
+			error = -EFAULT;
+	}
+	return error;
+}
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+SYSCALL_DEFINE4(timer_settime32, timer_t, timer_id, int, flags,
+		struct old_itimerspec32 __user *, new,
+		struct old_itimerspec32 __user *, old)
+{
+	struct itimerspec64 new_spec, old_spec;
+	struct itimerspec64 *rtn = old ? &old_spec : NULL;
+	int error = 0;
+
+	if (!new)
+		return -EINVAL;
+	if (get_old_itimerspec32(&new_spec, new))
+		return -EFAULT;
+
+	error = do_timer_settime(timer_id, flags, &new_spec, rtn);
+	if (!error && old) {
+		if (put_old_itimerspec32(&old_spec, old))
+			error = -EFAULT;
+	}
+	return error;
+}
+#endif
+
+int common_timer_del(struct k_itimer *timer)
+{
+	const struct k_clock *kc = timer->kclock;
+
+	timer->it_interval = 0;
+	if (kc->timer_try_to_cancel(timer) < 0)
+		return TIMER_RETRY;
+	timer->it_active = 0;
+	return 0;
+}
+
+static inline int timer_delete_hook(struct k_itimer *timer)
+{
+	const struct k_clock *kc = timer->kclock;
+
+	if (WARN_ON_ONCE(!kc || !kc->timer_del))
+		return -EINVAL;
+	return kc->timer_del(timer);
+}
+
+/* Delete a POSIX.1b interval timer. */
+SYSCALL_DEFINE1(timer_delete, timer_t, timer_id)
+{
+	struct k_itimer *timer;
+	unsigned long flags;
+
+	timer = lock_timer(timer_id, &flags);
+
+retry_delete:
+	if (!timer)
+		return -EINVAL;
+
+	if (unlikely(timer_delete_hook(timer) == TIMER_RETRY)) {
+		/* Unlocks and relocks the timer if it still exists */
+		timer = timer_wait_running(timer, &flags);
+		goto retry_delete;
+	}
+
+	spin_lock(&current->sighand->siglock);
+	list_del(&timer->list);
+	spin_unlock(&current->sighand->siglock);
+	/*
+	 * This keeps any tasks waiting on the spin lock from thinking
+	 * they got something (see the lock code above).
+	 */
+	timer->it_signal = NULL;
+
+	unlock_timer(timer, flags);
+	release_posix_timer(timer, IT_ID_SET);
+	return 0;
+}
+
+/*
+ * Delete a timer if it is armed, remove it from the hash and schedule it
+ * for RCU freeing.
+ */
+static void itimer_delete(struct k_itimer *timer)
+{
+	unsigned long flags;
+
+	/*
+	 * irqsave is required to make timer_wait_running() work.
+	 */
+	spin_lock_irqsave(&timer->it_lock, flags);
+
+retry_delete:
+	/*
+	 * Even if the timer is not longer accessible from other tasks
+	 * it still might be armed and queued in the underlying timer
+	 * mechanism. Worse, that timer mechanism might run the expiry
+	 * function concurrently.
+	 */
+	if (timer_delete_hook(timer) == TIMER_RETRY) {
+		/*
+		 * Timer is expired concurrently, prevent livelocks
+		 * and pointless spinning on RT.
+		 *
+		 * timer_wait_running() drops timer::it_lock, which opens
+		 * the possibility for another task to delete the timer.
+		 *
+		 * That's not possible here because this is invoked from
+		 * do_exit() only for the last thread of the thread group.
+		 * So no other task can access and delete that timer.
+		 */
+		if (WARN_ON_ONCE(timer_wait_running(timer, &flags) != timer))
+			return;
+
+		goto retry_delete;
+	}
+	list_del(&timer->list);
+
+	spin_unlock_irqrestore(&timer->it_lock, flags);
+	release_posix_timer(timer, IT_ID_SET);
+}
+
+/*
+ * Invoked from do_exit() when the last thread of a thread group exits.
+ * At that point no other task can access the timers of the dying
+ * task anymore.
+ */
+void exit_itimers(struct task_struct *tsk)
+{
+	struct list_head timers;
+	struct k_itimer *tmr;
+
+	if (list_empty(&tsk->signal->posix_timers))
+		return;
+
+	/* Protect against concurrent read via /proc/$PID/timers */
+	spin_lock_irq(&tsk->sighand->siglock);
+	list_replace_init(&tsk->signal->posix_timers, &timers);
+	spin_unlock_irq(&tsk->sighand->siglock);
+
+	/* The timers are not longer accessible via tsk::signal */
+	while (!list_empty(&timers)) {
+		tmr = list_first_entry(&timers, struct k_itimer, list);
+		itimer_delete(tmr);
+	}
+}
+
+SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
+		const struct __kernel_timespec __user *, tp)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+	struct timespec64 new_tp;
+
+	if (!kc || !kc->clock_set)
+		return -EINVAL;
+
+	if (get_timespec64(&new_tp, tp))
+		return -EFAULT;
+
+	return kc->clock_set(which_clock, &new_tp);
+}
+
+SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
+		struct __kernel_timespec __user *, tp)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+	struct timespec64 kernel_tp;
+	int error;
+
+	if (!kc)
+		return -EINVAL;
+
+	error = kc->clock_get_timespec(which_clock, &kernel_tp);
+
+	if (!error && put_timespec64(&kernel_tp, tp))
+		error = -EFAULT;
+
+	return error;
+}
+
+int do_clock_adjtime(const clockid_t which_clock, struct __kernel_timex * ktx)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+
+	if (!kc)
+		return -EINVAL;
+	if (!kc->clock_adj)
+		return -EOPNOTSUPP;
+
+	return kc->clock_adj(which_clock, ktx);
+}
+
+SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
+		struct __kernel_timex __user *, utx)
+{
+	struct __kernel_timex ktx;
+	int err;
+
+	if (copy_from_user(&ktx, utx, sizeof(ktx)))
+		return -EFAULT;
+
+	err = do_clock_adjtime(which_clock, &ktx);
+
+	if (err >= 0 && copy_to_user(utx, &ktx, sizeof(ktx)))
+		return -EFAULT;
+
+	return err;
+}
+
+SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
+		struct __kernel_timespec __user *, tp)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+	struct timespec64 rtn_tp;
+	int error;
+
+	if (!kc)
+		return -EINVAL;
+
+	error = kc->clock_getres(which_clock, &rtn_tp);
+
+	if (!error && tp && put_timespec64(&rtn_tp, tp))
+		error = -EFAULT;
+
+	return error;
+}
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+
+SYSCALL_DEFINE2(clock_settime32, clockid_t, which_clock,
+		struct old_timespec32 __user *, tp)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+	struct timespec64 ts;
+
+	if (!kc || !kc->clock_set)
+		return -EINVAL;
+
+	if (get_old_timespec32(&ts, tp))
+		return -EFAULT;
+
+	return kc->clock_set(which_clock, &ts);
+}
+
+SYSCALL_DEFINE2(clock_gettime32, clockid_t, which_clock,
+		struct old_timespec32 __user *, tp)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+	struct timespec64 ts;
+	int err;
+
+	if (!kc)
+		return -EINVAL;
+
+	err = kc->clock_get_timespec(which_clock, &ts);
+
+	if (!err && put_old_timespec32(&ts, tp))
+		err = -EFAULT;
+
+	return err;
+}
+
+SYSCALL_DEFINE2(clock_adjtime32, clockid_t, which_clock,
+		struct old_timex32 __user *, utp)
+{
+	struct __kernel_timex ktx;
+	int err;
+
+	err = get_old_timex32(&ktx, utp);
+	if (err)
+		return err;
+
+	err = do_clock_adjtime(which_clock, &ktx);
+
+	if (err >= 0 && put_old_timex32(utp, &ktx))
+		return -EFAULT;
+
+	return err;
+}
+
+SYSCALL_DEFINE2(clock_getres_time32, clockid_t, which_clock,
+		struct old_timespec32 __user *, tp)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+	struct timespec64 ts;
+	int err;
+
+	if (!kc)
+		return -EINVAL;
+
+	err = kc->clock_getres(which_clock, &ts);
+	if (!err && tp && put_old_timespec32(&ts, tp))
+		return -EFAULT;
+
+	return err;
+}
+
+#endif
+
+/*
+ * nanosleep for monotonic and realtime clocks
+ */
+static int common_nsleep(const clockid_t which_clock, int flags,
+			 const struct timespec64 *rqtp)
+{
+	ktime_t texp = timespec64_to_ktime(*rqtp);
+
+	return hrtimer_nanosleep(texp, flags & TIMER_ABSTIME ?
+				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
+				 which_clock);
+}
+
+static int common_nsleep_timens(const clockid_t which_clock, int flags,
+			 const struct timespec64 *rqtp)
+{
+	ktime_t texp = timespec64_to_ktime(*rqtp);
+
+	if (flags & TIMER_ABSTIME)
+		texp = timens_ktime_to_host(which_clock, texp);
+
+	return hrtimer_nanosleep(texp, flags & TIMER_ABSTIME ?
+				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
+				 which_clock);
+}
+
+SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
+		const struct __kernel_timespec __user *, rqtp,
+		struct __kernel_timespec __user *, rmtp)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+	struct timespec64 t;
+
+	if (!kc)
+		return -EINVAL;
+	if (!kc->nsleep)
+		return -EOPNOTSUPP;
+
+	if (get_timespec64(&t, rqtp))
+		return -EFAULT;
+
+	if (!timespec64_valid(&t))
+		return -EINVAL;
+	if (flags & TIMER_ABSTIME)
+		rmtp = NULL;
+	current->restart_block.fn = do_no_restart_syscall;
+	current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
+	current->restart_block.nanosleep.rmtp = rmtp;
+
+	return kc->nsleep(which_clock, flags, &t);
+}
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+
+SYSCALL_DEFINE4(clock_nanosleep_time32, clockid_t, which_clock, int, flags,
+		struct old_timespec32 __user *, rqtp,
+		struct old_timespec32 __user *, rmtp)
+{
+	const struct k_clock *kc = clockid_to_kclock(which_clock);
+	struct timespec64 t;
+
+	if (!kc)
+		return -EINVAL;
+	if (!kc->nsleep)
+		return -EOPNOTSUPP;
+
+	if (get_old_timespec32(&t, rqtp))
+		return -EFAULT;
+
+	if (!timespec64_valid(&t))
+		return -EINVAL;
+	if (flags & TIMER_ABSTIME)
+		rmtp = NULL;
+	current->restart_block.fn = do_no_restart_syscall;
+	current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
+	current->restart_block.nanosleep.compat_rmtp = rmtp;
+
+	return kc->nsleep(which_clock, flags, &t);
+}
+
+#endif
+
+static const struct k_clock clock_realtime = {
+	.clock_getres		= posix_get_hrtimer_res,
+	.clock_get_timespec	= posix_get_realtime_timespec,
+	.clock_get_ktime	= posix_get_realtime_ktime,
+	.clock_set		= posix_clock_realtime_set,
+	.clock_adj		= posix_clock_realtime_adj,
+	.nsleep			= common_nsleep,
+	.timer_create		= common_timer_create,
+	.timer_set		= common_timer_set,
+	.timer_get		= common_timer_get,
+	.timer_del		= common_timer_del,
+	.timer_rearm		= common_hrtimer_rearm,
+	.timer_forward		= common_hrtimer_forward,
+	.timer_remaining	= common_hrtimer_remaining,
+	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
+	.timer_wait_running	= common_timer_wait_running,
+	.timer_arm		= common_hrtimer_arm,
+};
+
+static const struct k_clock clock_monotonic = {
+	.clock_getres		= posix_get_hrtimer_res,
+	.clock_get_timespec	= posix_get_monotonic_timespec,
+	.clock_get_ktime	= posix_get_monotonic_ktime,
+	.nsleep			= common_nsleep_timens,
+	.timer_create		= common_timer_create,
+	.timer_set		= common_timer_set,
+	.timer_get		= common_timer_get,
+	.timer_del		= common_timer_del,
+	.timer_rearm		= common_hrtimer_rearm,
+	.timer_forward		= common_hrtimer_forward,
+	.timer_remaining	= common_hrtimer_remaining,
+	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
+	.timer_wait_running	= common_timer_wait_running,
+	.timer_arm		= common_hrtimer_arm,
+};
+
+static const struct k_clock clock_monotonic_raw = {
+	.clock_getres		= posix_get_hrtimer_res,
+	.clock_get_timespec	= posix_get_monotonic_raw,
+};
+
+static const struct k_clock clock_realtime_coarse = {
+	.clock_getres		= posix_get_coarse_res,
+	.clock_get_timespec	= posix_get_realtime_coarse,
+};
+
+static const struct k_clock clock_monotonic_coarse = {
+	.clock_getres		= posix_get_coarse_res,
+	.clock_get_timespec	= posix_get_monotonic_coarse,
+};
+
+static const struct k_clock clock_tai = {
+	.clock_getres		= posix_get_hrtimer_res,
+	.clock_get_ktime	= posix_get_tai_ktime,
+	.clock_get_timespec	= posix_get_tai_timespec,
+	.nsleep			= common_nsleep,
+	.timer_create		= common_timer_create,
+	.timer_set		= common_timer_set,
+	.timer_get		= common_timer_get,
+	.timer_del		= common_timer_del,
+	.timer_rearm		= common_hrtimer_rearm,
+	.timer_forward		= common_hrtimer_forward,
+	.timer_remaining	= common_hrtimer_remaining,
+	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
+	.timer_wait_running	= common_timer_wait_running,
+	.timer_arm		= common_hrtimer_arm,
+};
+
+static const struct k_clock clock_boottime = {
+	.clock_getres		= posix_get_hrtimer_res,
+	.clock_get_ktime	= posix_get_boottime_ktime,
+	.clock_get_timespec	= posix_get_boottime_timespec,
+	.nsleep			= common_nsleep_timens,
+	.timer_create		= common_timer_create,
+	.timer_set		= common_timer_set,
+	.timer_get		= common_timer_get,
+	.timer_del		= common_timer_del,
+	.timer_rearm		= common_hrtimer_rearm,
+	.timer_forward		= common_hrtimer_forward,
+	.timer_remaining	= common_hrtimer_remaining,
+	.timer_try_to_cancel	= common_hrtimer_try_to_cancel,
+	.timer_wait_running	= common_timer_wait_running,
+	.timer_arm		= common_hrtimer_arm,
+};
+
+static const struct k_clock * const posix_clocks[] = {
+	[CLOCK_REALTIME]		= &clock_realtime,
+	[CLOCK_MONOTONIC]		= &clock_monotonic,
+	[CLOCK_PROCESS_CPUTIME_ID]	= &clock_process,
+	[CLOCK_THREAD_CPUTIME_ID]	= &clock_thread,
+	[CLOCK_MONOTONIC_RAW]		= &clock_monotonic_raw,
+	[CLOCK_REALTIME_COARSE]		= &clock_realtime_coarse,
+	[CLOCK_MONOTONIC_COARSE]	= &clock_monotonic_coarse,
+	[CLOCK_BOOTTIME]		= &clock_boottime,
+	[CLOCK_REALTIME_ALARM]		= &alarm_clock,
+	[CLOCK_BOOTTIME_ALARM]		= &alarm_clock,
+	[CLOCK_TAI]			= &clock_tai,
+};
+
+static const struct k_clock *clockid_to_kclock(const clockid_t id)
+{
+	clockid_t idx = id;
+
+	if (id < 0) {
+		return (id & CLOCKFD_MASK) == CLOCKFD ?
+			&clock_posix_dynamic : &clock_posix_cpu;
+	}
+
+	if (id >= ARRAY_SIZE(posix_clocks))
+		return NULL;
+
+	return posix_clocks[array_index_nospec(idx, ARRAY_SIZE(posix_clocks))];
+}
diff --git a/kernel/time/posix-timers.h b/kernel/time/posix-timers.h
new file mode 100644
index 000000000..f32a2ebba
--- /dev/null
+++ b/kernel/time/posix-timers.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#define TIMER_RETRY 1
+
+struct k_clock {
+	int	(*clock_getres)(const clockid_t which_clock,
+				struct timespec64 *tp);
+	int	(*clock_set)(const clockid_t which_clock,
+			     const struct timespec64 *tp);
+	/* Returns the clock value in the current time namespace. */
+	int	(*clock_get_timespec)(const clockid_t which_clock,
+				      struct timespec64 *tp);
+	/* Returns the clock value in the root time namespace. */
+	ktime_t	(*clock_get_ktime)(const clockid_t which_clock);
+	int	(*clock_adj)(const clockid_t which_clock, struct __kernel_timex *tx);
+	int	(*timer_create)(struct k_itimer *timer);
+	int	(*nsleep)(const clockid_t which_clock, int flags,
+			  const struct timespec64 *);
+	int	(*timer_set)(struct k_itimer *timr, int flags,
+			     struct itimerspec64 *new_setting,
+			     struct itimerspec64 *old_setting);
+	int	(*timer_del)(struct k_itimer *timr);
+	void	(*timer_get)(struct k_itimer *timr,
+			     struct itimerspec64 *cur_setting);
+	void	(*timer_rearm)(struct k_itimer *timr);
+	s64	(*timer_forward)(struct k_itimer *timr, ktime_t now);
+	ktime_t	(*timer_remaining)(struct k_itimer *timr, ktime_t now);
+	int	(*timer_try_to_cancel)(struct k_itimer *timr);
+	void	(*timer_arm)(struct k_itimer *timr, ktime_t expires,
+			     bool absolute, bool sigev_none);
+	void	(*timer_wait_running)(struct k_itimer *timr);
+};
+
+extern const struct k_clock clock_posix_cpu;
+extern const struct k_clock clock_posix_dynamic;
+extern const struct k_clock clock_process;
+extern const struct k_clock clock_thread;
+extern const struct k_clock alarm_clock;
+
+int posix_timer_event(struct k_itimer *timr, int si_private);
+
+void common_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting);
+int common_timer_set(struct k_itimer *timr, int flags,
+		     struct itimerspec64 *new_setting,
+		     struct itimerspec64 *old_setting);
+int common_timer_del(struct k_itimer *timer);
diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
new file mode 100644
index 000000000..8464c5acc
--- /dev/null
+++ b/kernel/time/sched_clock.c
@@ -0,0 +1,296 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic sched_clock() support, to extend low level hardware time
+ * counters to full 64-bit ns values.
+ */
+#include <linux/clocksource.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/ktime.h>
+#include <linux/kernel.h>
+#include <linux/math.h>
+#include <linux/moduleparam.h>
+#include <linux/sched.h>
+#include <linux/sched/clock.h>
+#include <linux/syscore_ops.h>
+#include <linux/hrtimer.h>
+#include <linux/sched_clock.h>
+#include <linux/seqlock.h>
+#include <linux/bitops.h>
+
+#include "timekeeping.h"
+
+/**
+ * struct clock_data - all data needed for sched_clock() (including
+ *                     registration of a new clock source)
+ *
+ * @seq:		Sequence counter for protecting updates. The lowest
+ *			bit is the index for @read_data.
+ * @read_data:		Data required to read from sched_clock.
+ * @wrap_kt:		Duration for which clock can run before wrapping.
+ * @rate:		Tick rate of the registered clock.
+ * @actual_read_sched_clock: Registered hardware level clock read function.
+ *
+ * The ordering of this structure has been chosen to optimize cache
+ * performance. In particular 'seq' and 'read_data[0]' (combined) should fit
+ * into a single 64-byte cache line.
+ */
+struct clock_data {
+	seqcount_latch_t	seq;
+	struct clock_read_data	read_data[2];
+	ktime_t			wrap_kt;
+	unsigned long		rate;
+
+	u64 (*actual_read_sched_clock)(void);
+};
+
+static struct hrtimer sched_clock_timer;
+static int irqtime = -1;
+
+core_param(irqtime, irqtime, int, 0400);
+
+static u64 notrace jiffy_sched_clock_read(void)
+{
+	/*
+	 * We don't need to use get_jiffies_64 on 32-bit arches here
+	 * because we register with BITS_PER_LONG
+	 */
+	return (u64)(jiffies - INITIAL_JIFFIES);
+}
+
+static struct clock_data cd ____cacheline_aligned = {
+	.read_data[0] = { .mult = NSEC_PER_SEC / HZ,
+			  .read_sched_clock = jiffy_sched_clock_read, },
+	.actual_read_sched_clock = jiffy_sched_clock_read,
+};
+
+static inline u64 notrace cyc_to_ns(u64 cyc, u32 mult, u32 shift)
+{
+	return (cyc * mult) >> shift;
+}
+
+notrace struct clock_read_data *sched_clock_read_begin(unsigned int *seq)
+{
+	*seq = raw_read_seqcount_latch(&cd.seq);
+	return cd.read_data + (*seq & 1);
+}
+
+notrace int sched_clock_read_retry(unsigned int seq)
+{
+	return read_seqcount_latch_retry(&cd.seq, seq);
+}
+
+unsigned long long notrace sched_clock(void)
+{
+	u64 cyc, res;
+	unsigned int seq;
+	struct clock_read_data *rd;
+
+	do {
+		rd = sched_clock_read_begin(&seq);
+
+		cyc = (rd->read_sched_clock() - rd->epoch_cyc) &
+		      rd->sched_clock_mask;
+		res = rd->epoch_ns + cyc_to_ns(cyc, rd->mult, rd->shift);
+	} while (sched_clock_read_retry(seq));
+
+	return res;
+}
+
+/*
+ * Updating the data required to read the clock.
+ *
+ * sched_clock() will never observe mis-matched data even if called from
+ * an NMI. We do this by maintaining an odd/even copy of the data and
+ * steering sched_clock() to one or the other using a sequence counter.
+ * In order to preserve the data cache profile of sched_clock() as much
+ * as possible the system reverts back to the even copy when the update
+ * completes; the odd copy is used *only* during an update.
+ */
+static void update_clock_read_data(struct clock_read_data *rd)
+{
+	/* update the backup (odd) copy with the new data */
+	cd.read_data[1] = *rd;
+
+	/* steer readers towards the odd copy */
+	raw_write_seqcount_latch(&cd.seq);
+
+	/* now its safe for us to update the normal (even) copy */
+	cd.read_data[0] = *rd;
+
+	/* switch readers back to the even copy */
+	raw_write_seqcount_latch(&cd.seq);
+}
+
+/*
+ * Atomically update the sched_clock() epoch.
+ */
+static void update_sched_clock(void)
+{
+	u64 cyc;
+	u64 ns;
+	struct clock_read_data rd;
+
+	rd = cd.read_data[0];
+
+	cyc = cd.actual_read_sched_clock();
+	ns = rd.epoch_ns + cyc_to_ns((cyc - rd.epoch_cyc) & rd.sched_clock_mask, rd.mult, rd.shift);
+
+	rd.epoch_ns = ns;
+	rd.epoch_cyc = cyc;
+
+	update_clock_read_data(&rd);
+}
+
+static enum hrtimer_restart sched_clock_poll(struct hrtimer *hrt)
+{
+	update_sched_clock();
+	hrtimer_forward_now(hrt, cd.wrap_kt);
+
+	return HRTIMER_RESTART;
+}
+
+void __init
+sched_clock_register(u64 (*read)(void), int bits, unsigned long rate)
+{
+	u64 res, wrap, new_mask, new_epoch, cyc, ns;
+	u32 new_mult, new_shift;
+	unsigned long r, flags;
+	char r_unit;
+	struct clock_read_data rd;
+
+	if (cd.rate > rate)
+		return;
+
+	/* Cannot register a sched_clock with interrupts on */
+	local_irq_save(flags);
+
+	/* Calculate the mult/shift to convert counter ticks to ns. */
+	clocks_calc_mult_shift(&new_mult, &new_shift, rate, NSEC_PER_SEC, 3600);
+
+	new_mask = CLOCKSOURCE_MASK(bits);
+	cd.rate = rate;
+
+	/* Calculate how many nanosecs until we risk wrapping */
+	wrap = clocks_calc_max_nsecs(new_mult, new_shift, 0, new_mask, NULL);
+	cd.wrap_kt = ns_to_ktime(wrap);
+
+	rd = cd.read_data[0];
+
+	/* Update epoch for new counter and update 'epoch_ns' from old counter*/
+	new_epoch = read();
+	cyc = cd.actual_read_sched_clock();
+	ns = rd.epoch_ns + cyc_to_ns((cyc - rd.epoch_cyc) & rd.sched_clock_mask, rd.mult, rd.shift);
+	cd.actual_read_sched_clock = read;
+
+	rd.read_sched_clock	= read;
+	rd.sched_clock_mask	= new_mask;
+	rd.mult			= new_mult;
+	rd.shift		= new_shift;
+	rd.epoch_cyc		= new_epoch;
+	rd.epoch_ns		= ns;
+
+	update_clock_read_data(&rd);
+
+	if (sched_clock_timer.function != NULL) {
+		/* update timeout for clock wrap */
+		hrtimer_start(&sched_clock_timer, cd.wrap_kt,
+			      HRTIMER_MODE_REL_HARD);
+	}
+
+	r = rate;
+	if (r >= 4000000) {
+		r = DIV_ROUND_CLOSEST(r, 1000000);
+		r_unit = 'M';
+	} else if (r >= 4000) {
+		r = DIV_ROUND_CLOSEST(r, 1000);
+		r_unit = 'k';
+	} else {
+		r_unit = ' ';
+	}
+
+	/* Calculate the ns resolution of this counter */
+	res = cyc_to_ns(1ULL, new_mult, new_shift);
+
+	pr_info("sched_clock: %u bits at %lu%cHz, resolution %lluns, wraps every %lluns\n",
+		bits, r, r_unit, res, wrap);
+
+	/* Enable IRQ time accounting if we have a fast enough sched_clock() */
+	if (irqtime > 0 || (irqtime == -1 && rate >= 1000000))
+		enable_sched_clock_irqtime();
+
+	local_irq_restore(flags);
+
+	pr_debug("Registered %pS as sched_clock source\n", read);
+}
+
+void __init generic_sched_clock_init(void)
+{
+	/*
+	 * If no sched_clock() function has been provided at that point,
+	 * make it the final one.
+	 */
+	if (cd.actual_read_sched_clock == jiffy_sched_clock_read)
+		sched_clock_register(jiffy_sched_clock_read, BITS_PER_LONG, HZ);
+
+	update_sched_clock();
+
+	/*
+	 * Start the timer to keep sched_clock() properly updated and
+	 * sets the initial epoch.
+	 */
+	hrtimer_init(&sched_clock_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	sched_clock_timer.function = sched_clock_poll;
+	hrtimer_start(&sched_clock_timer, cd.wrap_kt, HRTIMER_MODE_REL_HARD);
+}
+
+/*
+ * Clock read function for use when the clock is suspended.
+ *
+ * This function makes it appear to sched_clock() as if the clock
+ * stopped counting at its last update.
+ *
+ * This function must only be called from the critical
+ * section in sched_clock(). It relies on the read_seqcount_retry()
+ * at the end of the critical section to be sure we observe the
+ * correct copy of 'epoch_cyc'.
+ */
+static u64 notrace suspended_sched_clock_read(void)
+{
+	unsigned int seq = raw_read_seqcount_latch(&cd.seq);
+
+	return cd.read_data[seq & 1].epoch_cyc;
+}
+
+int sched_clock_suspend(void)
+{
+	struct clock_read_data *rd = &cd.read_data[0];
+
+	update_sched_clock();
+	hrtimer_cancel(&sched_clock_timer);
+	rd->read_sched_clock = suspended_sched_clock_read;
+
+	return 0;
+}
+
+void sched_clock_resume(void)
+{
+	struct clock_read_data *rd = &cd.read_data[0];
+
+	rd->epoch_cyc = cd.actual_read_sched_clock();
+	hrtimer_start(&sched_clock_timer, cd.wrap_kt, HRTIMER_MODE_REL_HARD);
+	rd->read_sched_clock = cd.actual_read_sched_clock;
+}
+
+static struct syscore_ops sched_clock_ops = {
+	.suspend	= sched_clock_suspend,
+	.resume		= sched_clock_resume,
+};
+
+static int __init sched_clock_syscore_init(void)
+{
+	register_syscore_ops(&sched_clock_ops);
+
+	return 0;
+}
+device_initcall(sched_clock_syscore_init);
diff --git a/kernel/time/test_udelay.c b/kernel/time/test_udelay.c
new file mode 100644
index 000000000..20d5df631
--- /dev/null
+++ b/kernel/time/test_udelay.c
@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * udelay() test kernel module
+ *
+ * Test is executed by writing and reading to /sys/kernel/debug/udelay_test
+ * Tests are configured by writing: USECS ITERATIONS
+ * Tests are executed by reading from the same file.
+ * Specifying usecs of 0 or negative values will run multiples tests.
+ *
+ * Copyright (C) 2014 Google, Inc.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/ktime.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+
+#define DEFAULT_ITERATIONS 100
+
+#define DEBUGFS_FILENAME "udelay_test"
+
+static DEFINE_MUTEX(udelay_test_lock);
+static int udelay_test_usecs;
+static int udelay_test_iterations = DEFAULT_ITERATIONS;
+
+static int udelay_test_single(struct seq_file *s, int usecs, uint32_t iters)
+{
+	int min = 0, max = 0, fail_count = 0;
+	uint64_t sum = 0;
+	uint64_t avg;
+	int i;
+	/* Allow udelay to be up to 0.5% fast */
+	int allowed_error_ns = usecs * 5;
+
+	for (i = 0; i < iters; ++i) {
+		s64 kt1, kt2;
+		int time_passed;
+
+		kt1 = ktime_get_ns();
+		udelay(usecs);
+		kt2 = ktime_get_ns();
+		time_passed = kt2 - kt1;
+
+		if (i == 0 || time_passed < min)
+			min = time_passed;
+		if (i == 0 || time_passed > max)
+			max = time_passed;
+		if ((time_passed + allowed_error_ns) / 1000 < usecs)
+			++fail_count;
+		WARN_ON(time_passed < 0);
+		sum += time_passed;
+	}
+
+	avg = sum;
+	do_div(avg, iters);
+	seq_printf(s, "%d usecs x %d: exp=%d allowed=%d min=%d avg=%lld max=%d",
+			usecs, iters, usecs * 1000,
+			(usecs * 1000) - allowed_error_ns, min, avg, max);
+	if (fail_count)
+		seq_printf(s, " FAIL=%d", fail_count);
+	seq_puts(s, "\n");
+
+	return 0;
+}
+
+static int udelay_test_show(struct seq_file *s, void *v)
+{
+	int usecs;
+	int iters;
+	int ret = 0;
+
+	mutex_lock(&udelay_test_lock);
+	usecs = udelay_test_usecs;
+	iters = udelay_test_iterations;
+	mutex_unlock(&udelay_test_lock);
+
+	if (usecs > 0 && iters > 0) {
+		return udelay_test_single(s, usecs, iters);
+	} else if (usecs == 0) {
+		struct timespec64 ts;
+
+		ktime_get_ts64(&ts);
+		seq_printf(s, "udelay() test (lpj=%ld kt=%lld.%09ld)\n",
+				loops_per_jiffy, (s64)ts.tv_sec, ts.tv_nsec);
+		seq_puts(s, "usage:\n");
+		seq_puts(s, "echo USECS [ITERS] > " DEBUGFS_FILENAME "\n");
+		seq_puts(s, "cat " DEBUGFS_FILENAME "\n");
+	}
+
+	return ret;
+}
+
+static int udelay_test_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, udelay_test_show, inode->i_private);
+}
+
+static ssize_t udelay_test_write(struct file *file, const char __user *buf,
+		size_t count, loff_t *pos)
+{
+	char lbuf[32];
+	int ret;
+	int usecs;
+	int iters;
+
+	if (count >= sizeof(lbuf))
+		return -EINVAL;
+
+	if (copy_from_user(lbuf, buf, count))
+		return -EFAULT;
+	lbuf[count] = '\0';
+
+	ret = sscanf(lbuf, "%d %d", &usecs, &iters);
+	if (ret < 1)
+		return -EINVAL;
+	else if (ret < 2)
+		iters = DEFAULT_ITERATIONS;
+
+	mutex_lock(&udelay_test_lock);
+	udelay_test_usecs = usecs;
+	udelay_test_iterations = iters;
+	mutex_unlock(&udelay_test_lock);
+
+	return count;
+}
+
+static const struct file_operations udelay_test_debugfs_ops = {
+	.owner = THIS_MODULE,
+	.open = udelay_test_open,
+	.read = seq_read,
+	.write = udelay_test_write,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static int __init udelay_test_init(void)
+{
+	mutex_lock(&udelay_test_lock);
+	debugfs_create_file(DEBUGFS_FILENAME, S_IRUSR, NULL, NULL,
+			    &udelay_test_debugfs_ops);
+	mutex_unlock(&udelay_test_lock);
+
+	return 0;
+}
+
+module_init(udelay_test_init);
+
+static void __exit udelay_test_exit(void)
+{
+	mutex_lock(&udelay_test_lock);
+	debugfs_lookup_and_remove(DEBUGFS_FILENAME, NULL);
+	mutex_unlock(&udelay_test_lock);
+}
+
+module_exit(udelay_test_exit);
+
+MODULE_AUTHOR("David Riley <davidriley@chromium.org>");
+MODULE_LICENSE("GPL");
diff --git a/kernel/time/tick-broadcast-hrtimer.c b/kernel/time/tick-broadcast-hrtimer.c
new file mode 100644
index 000000000..797eb9310
--- /dev/null
+++ b/kernel/time/tick-broadcast-hrtimer.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Emulate a local clock event device via a pseudo clock device.
+ */
+#include <linux/cpu.h>
+#include <linux/err.h>
+#include <linux/hrtimer.h>
+#include <linux/interrupt.h>
+#include <linux/percpu.h>
+#include <linux/profile.h>
+#include <linux/clockchips.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/module.h>
+
+#include "tick-internal.h"
+
+static struct hrtimer bctimer;
+
+static int bc_shutdown(struct clock_event_device *evt)
+{
+	/*
+	 * Note, we cannot cancel the timer here as we might
+	 * run into the following live lock scenario:
+	 *
+	 * cpu 0		cpu1
+	 * lock(broadcast_lock);
+	 *			hrtimer_interrupt()
+	 *			bc_handler()
+	 *			   tick_handle_oneshot_broadcast();
+	 *			    lock(broadcast_lock);
+	 * hrtimer_cancel()
+	 *  wait_for_callback()
+	 */
+	hrtimer_try_to_cancel(&bctimer);
+	return 0;
+}
+
+/*
+ * This is called from the guts of the broadcast code when the cpu
+ * which is about to enter idle has the earliest broadcast timer event.
+ */
+static int bc_set_next(ktime_t expires, struct clock_event_device *bc)
+{
+	/*
+	 * This is called either from enter/exit idle code or from the
+	 * broadcast handler. In all cases tick_broadcast_lock is held.
+	 *
+	 * hrtimer_cancel() cannot be called here neither from the
+	 * broadcast handler nor from the enter/exit idle code. The idle
+	 * code can run into the problem described in bc_shutdown() and the
+	 * broadcast handler cannot wait for itself to complete for obvious
+	 * reasons.
+	 *
+	 * Each caller tries to arm the hrtimer on its own CPU, but if the
+	 * hrtimer callback function is currently running, then
+	 * hrtimer_start() cannot move it and the timer stays on the CPU on
+	 * which it is assigned at the moment.
+	 *
+	 * As this can be called from idle code, the hrtimer_start()
+	 * invocation has to be wrapped with RCU_NONIDLE() as
+	 * hrtimer_start() can call into tracing.
+	 */
+	RCU_NONIDLE( {
+		hrtimer_start(&bctimer, expires, HRTIMER_MODE_ABS_PINNED_HARD);
+		/*
+		 * The core tick broadcast mode expects bc->bound_on to be set
+		 * correctly to prevent a CPU which has the broadcast hrtimer
+		 * armed from going deep idle.
+		 *
+		 * As tick_broadcast_lock is held, nothing can change the cpu
+		 * base which was just established in hrtimer_start() above. So
+		 * the below access is safe even without holding the hrtimer
+		 * base lock.
+		 */
+		bc->bound_on = bctimer.base->cpu_base->cpu;
+	} );
+	return 0;
+}
+
+static struct clock_event_device ce_broadcast_hrtimer = {
+	.name			= "bc_hrtimer",
+	.set_state_shutdown	= bc_shutdown,
+	.set_next_ktime		= bc_set_next,
+	.features		= CLOCK_EVT_FEAT_ONESHOT |
+				  CLOCK_EVT_FEAT_KTIME |
+				  CLOCK_EVT_FEAT_HRTIMER,
+	.rating			= 0,
+	.bound_on		= -1,
+	.min_delta_ns		= 1,
+	.max_delta_ns		= KTIME_MAX,
+	.min_delta_ticks	= 1,
+	.max_delta_ticks	= ULONG_MAX,
+	.mult			= 1,
+	.shift			= 0,
+	.cpumask		= cpu_possible_mask,
+};
+
+static enum hrtimer_restart bc_handler(struct hrtimer *t)
+{
+	ce_broadcast_hrtimer.event_handler(&ce_broadcast_hrtimer);
+
+	return HRTIMER_NORESTART;
+}
+
+void tick_setup_hrtimer_broadcast(void)
+{
+	hrtimer_init(&bctimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
+	bctimer.function = bc_handler;
+	clockevents_register_device(&ce_broadcast_hrtimer);
+}
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
new file mode 100644
index 000000000..0916cc9ad
--- /dev/null
+++ b/kernel/time/tick-broadcast.c
@@ -0,0 +1,1211 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file contains functions which emulate a local clock-event
+ * device via a broadcast event source.
+ *
+ * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
+ * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
+ * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
+ */
+#include <linux/cpu.h>
+#include <linux/err.h>
+#include <linux/hrtimer.h>
+#include <linux/interrupt.h>
+#include <linux/percpu.h>
+#include <linux/profile.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/module.h>
+
+#include "tick-internal.h"
+
+/*
+ * Broadcast support for broken x86 hardware, where the local apic
+ * timer stops in C3 state.
+ */
+
+static struct tick_device tick_broadcast_device;
+static cpumask_var_t tick_broadcast_mask __cpumask_var_read_mostly;
+static cpumask_var_t tick_broadcast_on __cpumask_var_read_mostly;
+static cpumask_var_t tmpmask __cpumask_var_read_mostly;
+static int tick_broadcast_forced;
+
+static __cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(tick_broadcast_lock);
+
+#ifdef CONFIG_TICK_ONESHOT
+static DEFINE_PER_CPU(struct clock_event_device *, tick_oneshot_wakeup_device);
+
+static void tick_broadcast_setup_oneshot(struct clock_event_device *bc, bool from_periodic);
+static void tick_broadcast_clear_oneshot(int cpu);
+static void tick_resume_broadcast_oneshot(struct clock_event_device *bc);
+# ifdef CONFIG_HOTPLUG_CPU
+static void tick_broadcast_oneshot_offline(unsigned int cpu);
+# endif
+#else
+static inline void
+tick_broadcast_setup_oneshot(struct clock_event_device *bc, bool from_periodic) { BUG(); }
+static inline void tick_broadcast_clear_oneshot(int cpu) { }
+static inline void tick_resume_broadcast_oneshot(struct clock_event_device *bc) { }
+# ifdef CONFIG_HOTPLUG_CPU
+static inline void tick_broadcast_oneshot_offline(unsigned int cpu) { }
+# endif
+#endif
+
+/*
+ * Debugging: see timer_list.c
+ */
+struct tick_device *tick_get_broadcast_device(void)
+{
+	return &tick_broadcast_device;
+}
+
+struct cpumask *tick_get_broadcast_mask(void)
+{
+	return tick_broadcast_mask;
+}
+
+static struct clock_event_device *tick_get_oneshot_wakeup_device(int cpu);
+
+const struct clock_event_device *tick_get_wakeup_device(int cpu)
+{
+	return tick_get_oneshot_wakeup_device(cpu);
+}
+
+/*
+ * Start the device in periodic mode
+ */
+static void tick_broadcast_start_periodic(struct clock_event_device *bc)
+{
+	if (bc)
+		tick_setup_periodic(bc, 1);
+}
+
+/*
+ * Check, if the device can be utilized as broadcast device:
+ */
+static bool tick_check_broadcast_device(struct clock_event_device *curdev,
+					struct clock_event_device *newdev)
+{
+	if ((newdev->features & CLOCK_EVT_FEAT_DUMMY) ||
+	    (newdev->features & CLOCK_EVT_FEAT_PERCPU) ||
+	    (newdev->features & CLOCK_EVT_FEAT_C3STOP))
+		return false;
+
+	if (tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT &&
+	    !(newdev->features & CLOCK_EVT_FEAT_ONESHOT))
+		return false;
+
+	return !curdev || newdev->rating > curdev->rating;
+}
+
+#ifdef CONFIG_TICK_ONESHOT
+static struct clock_event_device *tick_get_oneshot_wakeup_device(int cpu)
+{
+	return per_cpu(tick_oneshot_wakeup_device, cpu);
+}
+
+static void tick_oneshot_wakeup_handler(struct clock_event_device *wd)
+{
+	/*
+	 * If we woke up early and the tick was reprogrammed in the
+	 * meantime then this may be spurious but harmless.
+	 */
+	tick_receive_broadcast();
+}
+
+static bool tick_set_oneshot_wakeup_device(struct clock_event_device *newdev,
+					   int cpu)
+{
+	struct clock_event_device *curdev = tick_get_oneshot_wakeup_device(cpu);
+
+	if (!newdev)
+		goto set_device;
+
+	if ((newdev->features & CLOCK_EVT_FEAT_DUMMY) ||
+	    (newdev->features & CLOCK_EVT_FEAT_C3STOP))
+		 return false;
+
+	if (!(newdev->features & CLOCK_EVT_FEAT_PERCPU) ||
+	    !(newdev->features & CLOCK_EVT_FEAT_ONESHOT))
+		return false;
+
+	if (!cpumask_equal(newdev->cpumask, cpumask_of(cpu)))
+		return false;
+
+	if (curdev && newdev->rating <= curdev->rating)
+		return false;
+
+	if (!try_module_get(newdev->owner))
+		return false;
+
+	newdev->event_handler = tick_oneshot_wakeup_handler;
+set_device:
+	clockevents_exchange_device(curdev, newdev);
+	per_cpu(tick_oneshot_wakeup_device, cpu) = newdev;
+	return true;
+}
+#else
+static struct clock_event_device *tick_get_oneshot_wakeup_device(int cpu)
+{
+	return NULL;
+}
+
+static bool tick_set_oneshot_wakeup_device(struct clock_event_device *newdev,
+					   int cpu)
+{
+	return false;
+}
+#endif
+
+/*
+ * Conditionally install/replace broadcast device
+ */
+void tick_install_broadcast_device(struct clock_event_device *dev, int cpu)
+{
+	struct clock_event_device *cur = tick_broadcast_device.evtdev;
+
+	if (tick_set_oneshot_wakeup_device(dev, cpu))
+		return;
+
+	if (!tick_check_broadcast_device(cur, dev))
+		return;
+
+	if (!try_module_get(dev->owner))
+		return;
+
+	clockevents_exchange_device(cur, dev);
+	if (cur)
+		cur->event_handler = clockevents_handle_noop;
+	tick_broadcast_device.evtdev = dev;
+	if (!cpumask_empty(tick_broadcast_mask))
+		tick_broadcast_start_periodic(dev);
+
+	if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
+		return;
+
+	/*
+	 * If the system already runs in oneshot mode, switch the newly
+	 * registered broadcast device to oneshot mode explicitly.
+	 */
+	if (tick_broadcast_oneshot_active()) {
+		tick_broadcast_switch_to_oneshot();
+		return;
+	}
+
+	/*
+	 * Inform all cpus about this. We might be in a situation
+	 * where we did not switch to oneshot mode because the per cpu
+	 * devices are affected by CLOCK_EVT_FEAT_C3STOP and the lack
+	 * of a oneshot capable broadcast device. Without that
+	 * notification the systems stays stuck in periodic mode
+	 * forever.
+	 */
+	tick_clock_notify();
+}
+
+/*
+ * Check, if the device is the broadcast device
+ */
+int tick_is_broadcast_device(struct clock_event_device *dev)
+{
+	return (dev && tick_broadcast_device.evtdev == dev);
+}
+
+int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq)
+{
+	int ret = -ENODEV;
+
+	if (tick_is_broadcast_device(dev)) {
+		raw_spin_lock(&tick_broadcast_lock);
+		ret = __clockevents_update_freq(dev, freq);
+		raw_spin_unlock(&tick_broadcast_lock);
+	}
+	return ret;
+}
+
+
+static void err_broadcast(const struct cpumask *mask)
+{
+	pr_crit_once("Failed to broadcast timer tick. Some CPUs may be unresponsive.\n");
+}
+
+static void tick_device_setup_broadcast_func(struct clock_event_device *dev)
+{
+	if (!dev->broadcast)
+		dev->broadcast = tick_broadcast;
+	if (!dev->broadcast) {
+		pr_warn_once("%s depends on broadcast, but no broadcast function available\n",
+			     dev->name);
+		dev->broadcast = err_broadcast;
+	}
+}
+
+/*
+ * Check, if the device is dysfunctional and a placeholder, which
+ * needs to be handled by the broadcast device.
+ */
+int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
+{
+	struct clock_event_device *bc = tick_broadcast_device.evtdev;
+	unsigned long flags;
+	int ret = 0;
+
+	raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
+
+	/*
+	 * Devices might be registered with both periodic and oneshot
+	 * mode disabled. This signals, that the device needs to be
+	 * operated from the broadcast device and is a placeholder for
+	 * the cpu local device.
+	 */
+	if (!tick_device_is_functional(dev)) {
+		dev->event_handler = tick_handle_periodic;
+		tick_device_setup_broadcast_func(dev);
+		cpumask_set_cpu(cpu, tick_broadcast_mask);
+		if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
+			tick_broadcast_start_periodic(bc);
+		else
+			tick_broadcast_setup_oneshot(bc, false);
+		ret = 1;
+	} else {
+		/*
+		 * Clear the broadcast bit for this cpu if the
+		 * device is not power state affected.
+		 */
+		if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
+			cpumask_clear_cpu(cpu, tick_broadcast_mask);
+		else
+			tick_device_setup_broadcast_func(dev);
+
+		/*
+		 * Clear the broadcast bit if the CPU is not in
+		 * periodic broadcast on state.
+		 */
+		if (!cpumask_test_cpu(cpu, tick_broadcast_on))
+			cpumask_clear_cpu(cpu, tick_broadcast_mask);
+
+		switch (tick_broadcast_device.mode) {
+		case TICKDEV_MODE_ONESHOT:
+			/*
+			 * If the system is in oneshot mode we can
+			 * unconditionally clear the oneshot mask bit,
+			 * because the CPU is running and therefore
+			 * not in an idle state which causes the power
+			 * state affected device to stop. Let the
+			 * caller initialize the device.
+			 */
+			tick_broadcast_clear_oneshot(cpu);
+			ret = 0;
+			break;
+
+		case TICKDEV_MODE_PERIODIC:
+			/*
+			 * If the system is in periodic mode, check
+			 * whether the broadcast device can be
+			 * switched off now.
+			 */
+			if (cpumask_empty(tick_broadcast_mask) && bc)
+				clockevents_shutdown(bc);
+			/*
+			 * If we kept the cpu in the broadcast mask,
+			 * tell the caller to leave the per cpu device
+			 * in shutdown state. The periodic interrupt
+			 * is delivered by the broadcast device, if
+			 * the broadcast device exists and is not
+			 * hrtimer based.
+			 */
+			if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER))
+				ret = cpumask_test_cpu(cpu, tick_broadcast_mask);
+			break;
+		default:
+			break;
+		}
+	}
+	raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
+	return ret;
+}
+
+int tick_receive_broadcast(void)
+{
+	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+	struct clock_event_device *evt = td->evtdev;
+
+	if (!evt)
+		return -ENODEV;
+
+	if (!evt->event_handler)
+		return -EINVAL;
+
+	evt->event_handler(evt);
+	return 0;
+}
+
+/*
+ * Broadcast the event to the cpus, which are set in the mask (mangled).
+ */
+static bool tick_do_broadcast(struct cpumask *mask)
+{
+	int cpu = smp_processor_id();
+	struct tick_device *td;
+	bool local = false;
+
+	/*
+	 * Check, if the current cpu is in the mask
+	 */
+	if (cpumask_test_cpu(cpu, mask)) {
+		struct clock_event_device *bc = tick_broadcast_device.evtdev;
+
+		cpumask_clear_cpu(cpu, mask);
+		/*
+		 * We only run the local handler, if the broadcast
+		 * device is not hrtimer based. Otherwise we run into
+		 * a hrtimer recursion.
+		 *
+		 * local timer_interrupt()
+		 *   local_handler()
+		 *     expire_hrtimers()
+		 *       bc_handler()
+		 *         local_handler()
+		 *	     expire_hrtimers()
+		 */
+		local = !(bc->features & CLOCK_EVT_FEAT_HRTIMER);
+	}
+
+	if (!cpumask_empty(mask)) {
+		/*
+		 * It might be necessary to actually check whether the devices
+		 * have different broadcast functions. For now, just use the
+		 * one of the first device. This works as long as we have this
+		 * misfeature only on x86 (lapic)
+		 */
+		td = &per_cpu(tick_cpu_device, cpumask_first(mask));
+		td->evtdev->broadcast(mask);
+	}
+	return local;
+}
+
+/*
+ * Periodic broadcast:
+ * - invoke the broadcast handlers
+ */
+static bool tick_do_periodic_broadcast(void)
+{
+	cpumask_and(tmpmask, cpu_online_mask, tick_broadcast_mask);
+	return tick_do_broadcast(tmpmask);
+}
+
+/*
+ * Event handler for periodic broadcast ticks
+ */
+static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
+{
+	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+	bool bc_local;
+
+	raw_spin_lock(&tick_broadcast_lock);
+
+	/* Handle spurious interrupts gracefully */
+	if (clockevent_state_shutdown(tick_broadcast_device.evtdev)) {
+		raw_spin_unlock(&tick_broadcast_lock);
+		return;
+	}
+
+	bc_local = tick_do_periodic_broadcast();
+
+	if (clockevent_state_oneshot(dev)) {
+		ktime_t next = ktime_add_ns(dev->next_event, TICK_NSEC);
+
+		clockevents_program_event(dev, next, true);
+	}
+	raw_spin_unlock(&tick_broadcast_lock);
+
+	/*
+	 * We run the handler of the local cpu after dropping
+	 * tick_broadcast_lock because the handler might deadlock when
+	 * trying to switch to oneshot mode.
+	 */
+	if (bc_local)
+		td->evtdev->event_handler(td->evtdev);
+}
+
+/**
+ * tick_broadcast_control - Enable/disable or force broadcast mode
+ * @mode:	The selected broadcast mode
+ *
+ * Called when the system enters a state where affected tick devices
+ * might stop. Note: TICK_BROADCAST_FORCE cannot be undone.
+ */
+void tick_broadcast_control(enum tick_broadcast_mode mode)
+{
+	struct clock_event_device *bc, *dev;
+	struct tick_device *td;
+	int cpu, bc_stopped;
+	unsigned long flags;
+
+	/* Protects also the local clockevent device. */
+	raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
+	td = this_cpu_ptr(&tick_cpu_device);
+	dev = td->evtdev;
+
+	/*
+	 * Is the device not affected by the powerstate ?
+	 */
+	if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))
+		goto out;
+
+	if (!tick_device_is_functional(dev))
+		goto out;
+
+	cpu = smp_processor_id();
+	bc = tick_broadcast_device.evtdev;
+	bc_stopped = cpumask_empty(tick_broadcast_mask);
+
+	switch (mode) {
+	case TICK_BROADCAST_FORCE:
+		tick_broadcast_forced = 1;
+		fallthrough;
+	case TICK_BROADCAST_ON:
+		cpumask_set_cpu(cpu, tick_broadcast_on);
+		if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_mask)) {
+			/*
+			 * Only shutdown the cpu local device, if:
+			 *
+			 * - the broadcast device exists
+			 * - the broadcast device is not a hrtimer based one
+			 * - the broadcast device is in periodic mode to
+			 *   avoid a hiccup during switch to oneshot mode
+			 */
+			if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER) &&
+			    tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
+				clockevents_shutdown(dev);
+		}
+		break;
+
+	case TICK_BROADCAST_OFF:
+		if (tick_broadcast_forced)
+			break;
+		cpumask_clear_cpu(cpu, tick_broadcast_on);
+		if (cpumask_test_and_clear_cpu(cpu, tick_broadcast_mask)) {
+			if (tick_broadcast_device.mode ==
+			    TICKDEV_MODE_PERIODIC)
+				tick_setup_periodic(dev, 0);
+		}
+		break;
+	}
+
+	if (bc) {
+		if (cpumask_empty(tick_broadcast_mask)) {
+			if (!bc_stopped)
+				clockevents_shutdown(bc);
+		} else if (bc_stopped) {
+			if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
+				tick_broadcast_start_periodic(bc);
+			else
+				tick_broadcast_setup_oneshot(bc, false);
+		}
+	}
+out:
+	raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
+}
+EXPORT_SYMBOL_GPL(tick_broadcast_control);
+
+/*
+ * Set the periodic handler depending on broadcast on/off
+ */
+void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
+{
+	if (!broadcast)
+		dev->event_handler = tick_handle_periodic;
+	else
+		dev->event_handler = tick_handle_periodic_broadcast;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void tick_shutdown_broadcast(void)
+{
+	struct clock_event_device *bc = tick_broadcast_device.evtdev;
+
+	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
+		if (bc && cpumask_empty(tick_broadcast_mask))
+			clockevents_shutdown(bc);
+	}
+}
+
+/*
+ * Remove a CPU from broadcasting
+ */
+void tick_broadcast_offline(unsigned int cpu)
+{
+	raw_spin_lock(&tick_broadcast_lock);
+	cpumask_clear_cpu(cpu, tick_broadcast_mask);
+	cpumask_clear_cpu(cpu, tick_broadcast_on);
+	tick_broadcast_oneshot_offline(cpu);
+	tick_shutdown_broadcast();
+	raw_spin_unlock(&tick_broadcast_lock);
+}
+
+#endif
+
+void tick_suspend_broadcast(void)
+{
+	struct clock_event_device *bc;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
+
+	bc = tick_broadcast_device.evtdev;
+	if (bc)
+		clockevents_shutdown(bc);
+
+	raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
+}
+
+/*
+ * This is called from tick_resume_local() on a resuming CPU. That's
+ * called from the core resume function, tick_unfreeze() and the magic XEN
+ * resume hackery.
+ *
+ * In none of these cases the broadcast device mode can change and the
+ * bit of the resuming CPU in the broadcast mask is safe as well.
+ */
+bool tick_resume_check_broadcast(void)
+{
+	if (tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT)
+		return false;
+	else
+		return cpumask_test_cpu(smp_processor_id(), tick_broadcast_mask);
+}
+
+void tick_resume_broadcast(void)
+{
+	struct clock_event_device *bc;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
+
+	bc = tick_broadcast_device.evtdev;
+
+	if (bc) {
+		clockevents_tick_resume(bc);
+
+		switch (tick_broadcast_device.mode) {
+		case TICKDEV_MODE_PERIODIC:
+			if (!cpumask_empty(tick_broadcast_mask))
+				tick_broadcast_start_periodic(bc);
+			break;
+		case TICKDEV_MODE_ONESHOT:
+			if (!cpumask_empty(tick_broadcast_mask))
+				tick_resume_broadcast_oneshot(bc);
+			break;
+		}
+	}
+	raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
+}
+
+#ifdef CONFIG_TICK_ONESHOT
+
+static cpumask_var_t tick_broadcast_oneshot_mask __cpumask_var_read_mostly;
+static cpumask_var_t tick_broadcast_pending_mask __cpumask_var_read_mostly;
+static cpumask_var_t tick_broadcast_force_mask __cpumask_var_read_mostly;
+
+/*
+ * Exposed for debugging: see timer_list.c
+ */
+struct cpumask *tick_get_broadcast_oneshot_mask(void)
+{
+	return tick_broadcast_oneshot_mask;
+}
+
+/*
+ * Called before going idle with interrupts disabled. Checks whether a
+ * broadcast event from the other core is about to happen. We detected
+ * that in tick_broadcast_oneshot_control(). The callsite can use this
+ * to avoid a deep idle transition as we are about to get the
+ * broadcast IPI right away.
+ */
+int tick_check_broadcast_expired(void)
+{
+	return cpumask_test_cpu(smp_processor_id(), tick_broadcast_force_mask);
+}
+
+/*
+ * Set broadcast interrupt affinity
+ */
+static void tick_broadcast_set_affinity(struct clock_event_device *bc,
+					const struct cpumask *cpumask)
+{
+	if (!(bc->features & CLOCK_EVT_FEAT_DYNIRQ))
+		return;
+
+	if (cpumask_equal(bc->cpumask, cpumask))
+		return;
+
+	bc->cpumask = cpumask;
+	irq_set_affinity(bc->irq, bc->cpumask);
+}
+
+static void tick_broadcast_set_event(struct clock_event_device *bc, int cpu,
+				     ktime_t expires)
+{
+	if (!clockevent_state_oneshot(bc))
+		clockevents_switch_state(bc, CLOCK_EVT_STATE_ONESHOT);
+
+	clockevents_program_event(bc, expires, 1);
+	tick_broadcast_set_affinity(bc, cpumask_of(cpu));
+}
+
+static void tick_resume_broadcast_oneshot(struct clock_event_device *bc)
+{
+	clockevents_switch_state(bc, CLOCK_EVT_STATE_ONESHOT);
+}
+
+/*
+ * Called from irq_enter() when idle was interrupted to reenable the
+ * per cpu device.
+ */
+void tick_check_oneshot_broadcast_this_cpu(void)
+{
+	if (cpumask_test_cpu(smp_processor_id(), tick_broadcast_oneshot_mask)) {
+		struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+
+		/*
+		 * We might be in the middle of switching over from
+		 * periodic to oneshot. If the CPU has not yet
+		 * switched over, leave the device alone.
+		 */
+		if (td->mode == TICKDEV_MODE_ONESHOT) {
+			clockevents_switch_state(td->evtdev,
+					      CLOCK_EVT_STATE_ONESHOT);
+		}
+	}
+}
+
+/*
+ * Handle oneshot mode broadcasting
+ */
+static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
+{
+	struct tick_device *td;
+	ktime_t now, next_event;
+	int cpu, next_cpu = 0;
+	bool bc_local;
+
+	raw_spin_lock(&tick_broadcast_lock);
+	dev->next_event = KTIME_MAX;
+	next_event = KTIME_MAX;
+	cpumask_clear(tmpmask);
+	now = ktime_get();
+	/* Find all expired events */
+	for_each_cpu(cpu, tick_broadcast_oneshot_mask) {
+		/*
+		 * Required for !SMP because for_each_cpu() reports
+		 * unconditionally CPU0 as set on UP kernels.
+		 */
+		if (!IS_ENABLED(CONFIG_SMP) &&
+		    cpumask_empty(tick_broadcast_oneshot_mask))
+			break;
+
+		td = &per_cpu(tick_cpu_device, cpu);
+		if (td->evtdev->next_event <= now) {
+			cpumask_set_cpu(cpu, tmpmask);
+			/*
+			 * Mark the remote cpu in the pending mask, so
+			 * it can avoid reprogramming the cpu local
+			 * timer in tick_broadcast_oneshot_control().
+			 */
+			cpumask_set_cpu(cpu, tick_broadcast_pending_mask);
+		} else if (td->evtdev->next_event < next_event) {
+			next_event = td->evtdev->next_event;
+			next_cpu = cpu;
+		}
+	}
+
+	/*
+	 * Remove the current cpu from the pending mask. The event is
+	 * delivered immediately in tick_do_broadcast() !
+	 */
+	cpumask_clear_cpu(smp_processor_id(), tick_broadcast_pending_mask);
+
+	/* Take care of enforced broadcast requests */
+	cpumask_or(tmpmask, tmpmask, tick_broadcast_force_mask);
+	cpumask_clear(tick_broadcast_force_mask);
+
+	/*
+	 * Sanity check. Catch the case where we try to broadcast to
+	 * offline cpus.
+	 */
+	if (WARN_ON_ONCE(!cpumask_subset(tmpmask, cpu_online_mask)))
+		cpumask_and(tmpmask, tmpmask, cpu_online_mask);
+
+	/*
+	 * Wakeup the cpus which have an expired event.
+	 */
+	bc_local = tick_do_broadcast(tmpmask);
+
+	/*
+	 * Two reasons for reprogram:
+	 *
+	 * - The global event did not expire any CPU local
+	 * events. This happens in dyntick mode, as the maximum PIT
+	 * delta is quite small.
+	 *
+	 * - There are pending events on sleeping CPUs which were not
+	 * in the event mask
+	 */
+	if (next_event != KTIME_MAX)
+		tick_broadcast_set_event(dev, next_cpu, next_event);
+
+	raw_spin_unlock(&tick_broadcast_lock);
+
+	if (bc_local) {
+		td = this_cpu_ptr(&tick_cpu_device);
+		td->evtdev->event_handler(td->evtdev);
+	}
+}
+
+static int broadcast_needs_cpu(struct clock_event_device *bc, int cpu)
+{
+	if (!(bc->features & CLOCK_EVT_FEAT_HRTIMER))
+		return 0;
+	if (bc->next_event == KTIME_MAX)
+		return 0;
+	return bc->bound_on == cpu ? -EBUSY : 0;
+}
+
+static void broadcast_shutdown_local(struct clock_event_device *bc,
+				     struct clock_event_device *dev)
+{
+	/*
+	 * For hrtimer based broadcasting we cannot shutdown the cpu
+	 * local device if our own event is the first one to expire or
+	 * if we own the broadcast timer.
+	 */
+	if (bc->features & CLOCK_EVT_FEAT_HRTIMER) {
+		if (broadcast_needs_cpu(bc, smp_processor_id()))
+			return;
+		if (dev->next_event < bc->next_event)
+			return;
+	}
+	clockevents_switch_state(dev, CLOCK_EVT_STATE_SHUTDOWN);
+}
+
+static int ___tick_broadcast_oneshot_control(enum tick_broadcast_state state,
+					     struct tick_device *td,
+					     int cpu)
+{
+	struct clock_event_device *bc, *dev = td->evtdev;
+	int ret = 0;
+	ktime_t now;
+
+	raw_spin_lock(&tick_broadcast_lock);
+	bc = tick_broadcast_device.evtdev;
+
+	if (state == TICK_BROADCAST_ENTER) {
+		/*
+		 * If the current CPU owns the hrtimer broadcast
+		 * mechanism, it cannot go deep idle and we do not add
+		 * the CPU to the broadcast mask. We don't have to go
+		 * through the EXIT path as the local timer is not
+		 * shutdown.
+		 */
+		ret = broadcast_needs_cpu(bc, cpu);
+		if (ret)
+			goto out;
+
+		/*
+		 * If the broadcast device is in periodic mode, we
+		 * return.
+		 */
+		if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
+			/* If it is a hrtimer based broadcast, return busy */
+			if (bc->features & CLOCK_EVT_FEAT_HRTIMER)
+				ret = -EBUSY;
+			goto out;
+		}
+
+		if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_oneshot_mask)) {
+			WARN_ON_ONCE(cpumask_test_cpu(cpu, tick_broadcast_pending_mask));
+
+			/* Conditionally shut down the local timer. */
+			broadcast_shutdown_local(bc, dev);
+
+			/*
+			 * We only reprogram the broadcast timer if we
+			 * did not mark ourself in the force mask and
+			 * if the cpu local event is earlier than the
+			 * broadcast event. If the current CPU is in
+			 * the force mask, then we are going to be
+			 * woken by the IPI right away; we return
+			 * busy, so the CPU does not try to go deep
+			 * idle.
+			 */
+			if (cpumask_test_cpu(cpu, tick_broadcast_force_mask)) {
+				ret = -EBUSY;
+			} else if (dev->next_event < bc->next_event) {
+				tick_broadcast_set_event(bc, cpu, dev->next_event);
+				/*
+				 * In case of hrtimer broadcasts the
+				 * programming might have moved the
+				 * timer to this cpu. If yes, remove
+				 * us from the broadcast mask and
+				 * return busy.
+				 */
+				ret = broadcast_needs_cpu(bc, cpu);
+				if (ret) {
+					cpumask_clear_cpu(cpu,
+						tick_broadcast_oneshot_mask);
+				}
+			}
+		}
+	} else {
+		if (cpumask_test_and_clear_cpu(cpu, tick_broadcast_oneshot_mask)) {
+			clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
+			/*
+			 * The cpu which was handling the broadcast
+			 * timer marked this cpu in the broadcast
+			 * pending mask and fired the broadcast
+			 * IPI. So we are going to handle the expired
+			 * event anyway via the broadcast IPI
+			 * handler. No need to reprogram the timer
+			 * with an already expired event.
+			 */
+			if (cpumask_test_and_clear_cpu(cpu,
+				       tick_broadcast_pending_mask))
+				goto out;
+
+			/*
+			 * Bail out if there is no next event.
+			 */
+			if (dev->next_event == KTIME_MAX)
+				goto out;
+			/*
+			 * If the pending bit is not set, then we are
+			 * either the CPU handling the broadcast
+			 * interrupt or we got woken by something else.
+			 *
+			 * We are no longer in the broadcast mask, so
+			 * if the cpu local expiry time is already
+			 * reached, we would reprogram the cpu local
+			 * timer with an already expired event.
+			 *
+			 * This can lead to a ping-pong when we return
+			 * to idle and therefore rearm the broadcast
+			 * timer before the cpu local timer was able
+			 * to fire. This happens because the forced
+			 * reprogramming makes sure that the event
+			 * will happen in the future and depending on
+			 * the min_delta setting this might be far
+			 * enough out that the ping-pong starts.
+			 *
+			 * If the cpu local next_event has expired
+			 * then we know that the broadcast timer
+			 * next_event has expired as well and
+			 * broadcast is about to be handled. So we
+			 * avoid reprogramming and enforce that the
+			 * broadcast handler, which did not run yet,
+			 * will invoke the cpu local handler.
+			 *
+			 * We cannot call the handler directly from
+			 * here, because we might be in a NOHZ phase
+			 * and we did not go through the irq_enter()
+			 * nohz fixups.
+			 */
+			now = ktime_get();
+			if (dev->next_event <= now) {
+				cpumask_set_cpu(cpu, tick_broadcast_force_mask);
+				goto out;
+			}
+			/*
+			 * We got woken by something else. Reprogram
+			 * the cpu local timer device.
+			 */
+			tick_program_event(dev->next_event, 1);
+		}
+	}
+out:
+	raw_spin_unlock(&tick_broadcast_lock);
+	return ret;
+}
+
+static int tick_oneshot_wakeup_control(enum tick_broadcast_state state,
+				       struct tick_device *td,
+				       int cpu)
+{
+	struct clock_event_device *dev, *wd;
+
+	dev = td->evtdev;
+	if (td->mode != TICKDEV_MODE_ONESHOT)
+		return -EINVAL;
+
+	wd = tick_get_oneshot_wakeup_device(cpu);
+	if (!wd)
+		return -ENODEV;
+
+	switch (state) {
+	case TICK_BROADCAST_ENTER:
+		clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT_STOPPED);
+		clockevents_switch_state(wd, CLOCK_EVT_STATE_ONESHOT);
+		clockevents_program_event(wd, dev->next_event, 1);
+		break;
+	case TICK_BROADCAST_EXIT:
+		/* We may have transitioned to oneshot mode while idle */
+		if (clockevent_get_state(wd) != CLOCK_EVT_STATE_ONESHOT)
+			return -ENODEV;
+	}
+
+	return 0;
+}
+
+int __tick_broadcast_oneshot_control(enum tick_broadcast_state state)
+{
+	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+	int cpu = smp_processor_id();
+
+	if (!tick_oneshot_wakeup_control(state, td, cpu))
+		return 0;
+
+	if (tick_broadcast_device.evtdev)
+		return ___tick_broadcast_oneshot_control(state, td, cpu);
+
+	/*
+	 * If there is no broadcast or wakeup device, tell the caller not
+	 * to go into deep idle.
+	 */
+	return -EBUSY;
+}
+
+/*
+ * Reset the one shot broadcast for a cpu
+ *
+ * Called with tick_broadcast_lock held
+ */
+static void tick_broadcast_clear_oneshot(int cpu)
+{
+	cpumask_clear_cpu(cpu, tick_broadcast_oneshot_mask);
+	cpumask_clear_cpu(cpu, tick_broadcast_pending_mask);
+}
+
+static void tick_broadcast_init_next_event(struct cpumask *mask,
+					   ktime_t expires)
+{
+	struct tick_device *td;
+	int cpu;
+
+	for_each_cpu(cpu, mask) {
+		td = &per_cpu(tick_cpu_device, cpu);
+		if (td->evtdev)
+			td->evtdev->next_event = expires;
+	}
+}
+
+static inline ktime_t tick_get_next_period(void)
+{
+	ktime_t next;
+
+	/*
+	 * Protect against concurrent updates (store /load tearing on
+	 * 32bit). It does not matter if the time is already in the
+	 * past. The broadcast device which is about to be programmed will
+	 * fire in any case.
+	 */
+	raw_spin_lock(&jiffies_lock);
+	next = tick_next_period;
+	raw_spin_unlock(&jiffies_lock);
+	return next;
+}
+
+/**
+ * tick_broadcast_setup_oneshot - setup the broadcast device
+ */
+static void tick_broadcast_setup_oneshot(struct clock_event_device *bc,
+					 bool from_periodic)
+{
+	int cpu = smp_processor_id();
+	ktime_t nexttick = 0;
+
+	if (!bc)
+		return;
+
+	/*
+	 * When the broadcast device was switched to oneshot by the first
+	 * CPU handling the NOHZ change, the other CPUs will reach this
+	 * code via hrtimer_run_queues() -> tick_check_oneshot_change()
+	 * too. Set up the broadcast device only once!
+	 */
+	if (bc->event_handler == tick_handle_oneshot_broadcast) {
+		/*
+		 * The CPU which switched from periodic to oneshot mode
+		 * set the broadcast oneshot bit for all other CPUs which
+		 * are in the general (periodic) broadcast mask to ensure
+		 * that CPUs which wait for the periodic broadcast are
+		 * woken up.
+		 *
+		 * Clear the bit for the local CPU as the set bit would
+		 * prevent the first tick_broadcast_enter() after this CPU
+		 * switched to oneshot state to program the broadcast
+		 * device.
+		 *
+		 * This code can also be reached via tick_broadcast_control(),
+		 * but this cannot avoid the tick_broadcast_clear_oneshot()
+		 * as that would break the periodic to oneshot transition of
+		 * secondary CPUs. But that's harmless as the below only
+		 * clears already cleared bits.
+		 */
+		tick_broadcast_clear_oneshot(cpu);
+		return;
+	}
+
+
+	bc->event_handler = tick_handle_oneshot_broadcast;
+	bc->next_event = KTIME_MAX;
+
+	/*
+	 * When the tick mode is switched from periodic to oneshot it must
+	 * be ensured that CPUs which are waiting for periodic broadcast
+	 * get their wake-up at the next tick.  This is achieved by ORing
+	 * tick_broadcast_mask into tick_broadcast_oneshot_mask.
+	 *
+	 * For other callers, e.g. broadcast device replacement,
+	 * tick_broadcast_oneshot_mask must not be touched as this would
+	 * set bits for CPUs which are already NOHZ, but not idle. Their
+	 * next tick_broadcast_enter() would observe the bit set and fail
+	 * to update the expiry time and the broadcast event device.
+	 */
+	if (from_periodic) {
+		cpumask_copy(tmpmask, tick_broadcast_mask);
+		/* Remove the local CPU as it is obviously not idle */
+		cpumask_clear_cpu(cpu, tmpmask);
+		cpumask_or(tick_broadcast_oneshot_mask, tick_broadcast_oneshot_mask, tmpmask);
+
+		/*
+		 * Ensure that the oneshot broadcast handler will wake the
+		 * CPUs which are still waiting for periodic broadcast.
+		 */
+		nexttick = tick_get_next_period();
+		tick_broadcast_init_next_event(tmpmask, nexttick);
+
+		/*
+		 * If the underlying broadcast clock event device is
+		 * already in oneshot state, then there is nothing to do.
+		 * The device was already armed for the next tick
+		 * in tick_handle_broadcast_periodic()
+		 */
+		if (clockevent_state_oneshot(bc))
+			return;
+	}
+
+	/*
+	 * When switching from periodic to oneshot mode arm the broadcast
+	 * device for the next tick.
+	 *
+	 * If the broadcast device has been replaced in oneshot mode and
+	 * the oneshot broadcast mask is not empty, then arm it to expire
+	 * immediately in order to reevaluate the next expiring timer.
+	 * @nexttick is 0 and therefore in the past which will cause the
+	 * clockevent code to force an event.
+	 *
+	 * For both cases the programming can be avoided when the oneshot
+	 * broadcast mask is empty.
+	 *
+	 * tick_broadcast_set_event() implicitly switches the broadcast
+	 * device to oneshot state.
+	 */
+	if (!cpumask_empty(tick_broadcast_oneshot_mask))
+		tick_broadcast_set_event(bc, cpu, nexttick);
+}
+
+/*
+ * Select oneshot operating mode for the broadcast device
+ */
+void tick_broadcast_switch_to_oneshot(void)
+{
+	struct clock_event_device *bc;
+	enum tick_device_mode oldmode;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
+
+	oldmode = tick_broadcast_device.mode;
+	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
+	bc = tick_broadcast_device.evtdev;
+	if (bc)
+		tick_broadcast_setup_oneshot(bc, oldmode == TICKDEV_MODE_PERIODIC);
+
+	raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+void hotplug_cpu__broadcast_tick_pull(int deadcpu)
+{
+	struct clock_event_device *bc;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
+	bc = tick_broadcast_device.evtdev;
+
+	if (bc && broadcast_needs_cpu(bc, deadcpu)) {
+		/* This moves the broadcast assignment to this CPU: */
+		clockevents_program_event(bc, bc->next_event, 1);
+	}
+	raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
+}
+
+/*
+ * Remove a dying CPU from broadcasting
+ */
+static void tick_broadcast_oneshot_offline(unsigned int cpu)
+{
+	if (tick_get_oneshot_wakeup_device(cpu))
+		tick_set_oneshot_wakeup_device(NULL, cpu);
+
+	/*
+	 * Clear the broadcast masks for the dead cpu, but do not stop
+	 * the broadcast device!
+	 */
+	cpumask_clear_cpu(cpu, tick_broadcast_oneshot_mask);
+	cpumask_clear_cpu(cpu, tick_broadcast_pending_mask);
+	cpumask_clear_cpu(cpu, tick_broadcast_force_mask);
+}
+#endif
+
+/*
+ * Check, whether the broadcast device is in one shot mode
+ */
+int tick_broadcast_oneshot_active(void)
+{
+	return tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT;
+}
+
+/*
+ * Check whether the broadcast device supports oneshot.
+ */
+bool tick_broadcast_oneshot_available(void)
+{
+	struct clock_event_device *bc = tick_broadcast_device.evtdev;
+
+	return bc ? bc->features & CLOCK_EVT_FEAT_ONESHOT : false;
+}
+
+#else
+int __tick_broadcast_oneshot_control(enum tick_broadcast_state state)
+{
+	struct clock_event_device *bc = tick_broadcast_device.evtdev;
+
+	if (!bc || (bc->features & CLOCK_EVT_FEAT_HRTIMER))
+		return -EBUSY;
+
+	return 0;
+}
+#endif
+
+void __init tick_broadcast_init(void)
+{
+	zalloc_cpumask_var(&tick_broadcast_mask, GFP_NOWAIT);
+	zalloc_cpumask_var(&tick_broadcast_on, GFP_NOWAIT);
+	zalloc_cpumask_var(&tmpmask, GFP_NOWAIT);
+#ifdef CONFIG_TICK_ONESHOT
+	zalloc_cpumask_var(&tick_broadcast_oneshot_mask, GFP_NOWAIT);
+	zalloc_cpumask_var(&tick_broadcast_pending_mask, GFP_NOWAIT);
+	zalloc_cpumask_var(&tick_broadcast_force_mask, GFP_NOWAIT);
+#endif
+}
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
new file mode 100644
index 000000000..e9138cd7a
--- /dev/null
+++ b/kernel/time/tick-common.c
@@ -0,0 +1,578 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file contains the base functions to manage periodic tick
+ * related events.
+ *
+ * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
+ * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
+ * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
+ */
+#include <linux/cpu.h>
+#include <linux/err.h>
+#include <linux/hrtimer.h>
+#include <linux/interrupt.h>
+#include <linux/nmi.h>
+#include <linux/percpu.h>
+#include <linux/profile.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <trace/events/power.h>
+
+#include <asm/irq_regs.h>
+
+#include "tick-internal.h"
+
+/*
+ * Tick devices
+ */
+DEFINE_PER_CPU(struct tick_device, tick_cpu_device);
+/*
+ * Tick next event: keeps track of the tick time. It's updated by the
+ * CPU which handles the tick and protected by jiffies_lock. There is
+ * no requirement to write hold the jiffies seqcount for it.
+ */
+ktime_t tick_next_period;
+
+/*
+ * tick_do_timer_cpu is a timer core internal variable which holds the CPU NR
+ * which is responsible for calling do_timer(), i.e. the timekeeping stuff. This
+ * variable has two functions:
+ *
+ * 1) Prevent a thundering herd issue of a gazillion of CPUs trying to grab the
+ *    timekeeping lock all at once. Only the CPU which is assigned to do the
+ *    update is handling it.
+ *
+ * 2) Hand off the duty in the NOHZ idle case by setting the value to
+ *    TICK_DO_TIMER_NONE, i.e. a non existing CPU. So the next cpu which looks
+ *    at it will take over and keep the time keeping alive.  The handover
+ *    procedure also covers cpu hotplug.
+ */
+int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT;
+#ifdef CONFIG_NO_HZ_FULL
+/*
+ * tick_do_timer_boot_cpu indicates the boot CPU temporarily owns
+ * tick_do_timer_cpu and it should be taken over by an eligible secondary
+ * when one comes online.
+ */
+static int tick_do_timer_boot_cpu __read_mostly = -1;
+#endif
+
+/*
+ * Debugging: see timer_list.c
+ */
+struct tick_device *tick_get_device(int cpu)
+{
+	return &per_cpu(tick_cpu_device, cpu);
+}
+
+/**
+ * tick_is_oneshot_available - check for a oneshot capable event device
+ */
+int tick_is_oneshot_available(void)
+{
+	struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
+
+	if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT))
+		return 0;
+	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
+		return 1;
+	return tick_broadcast_oneshot_available();
+}
+
+/*
+ * Periodic tick
+ */
+static void tick_periodic(int cpu)
+{
+	if (tick_do_timer_cpu == cpu) {
+		raw_spin_lock(&jiffies_lock);
+		write_seqcount_begin(&jiffies_seq);
+
+		/* Keep track of the next tick event */
+		tick_next_period = ktime_add_ns(tick_next_period, TICK_NSEC);
+
+		do_timer(1);
+		write_seqcount_end(&jiffies_seq);
+		raw_spin_unlock(&jiffies_lock);
+		update_wall_time();
+	}
+
+	update_process_times(user_mode(get_irq_regs()));
+	profile_tick(CPU_PROFILING);
+}
+
+/*
+ * Event handler for periodic ticks
+ */
+void tick_handle_periodic(struct clock_event_device *dev)
+{
+	int cpu = smp_processor_id();
+	ktime_t next = dev->next_event;
+
+	tick_periodic(cpu);
+
+#if defined(CONFIG_HIGH_RES_TIMERS) || defined(CONFIG_NO_HZ_COMMON)
+	/*
+	 * The cpu might have transitioned to HIGHRES or NOHZ mode via
+	 * update_process_times() -> run_local_timers() ->
+	 * hrtimer_run_queues().
+	 */
+	if (dev->event_handler != tick_handle_periodic)
+		return;
+#endif
+
+	if (!clockevent_state_oneshot(dev))
+		return;
+	for (;;) {
+		/*
+		 * Setup the next period for devices, which do not have
+		 * periodic mode:
+		 */
+		next = ktime_add_ns(next, TICK_NSEC);
+
+		if (!clockevents_program_event(dev, next, false))
+			return;
+		/*
+		 * Have to be careful here. If we're in oneshot mode,
+		 * before we call tick_periodic() in a loop, we need
+		 * to be sure we're using a real hardware clocksource.
+		 * Otherwise we could get trapped in an infinite
+		 * loop, as the tick_periodic() increments jiffies,
+		 * which then will increment time, possibly causing
+		 * the loop to trigger again and again.
+		 */
+		if (timekeeping_valid_for_hres())
+			tick_periodic(cpu);
+	}
+}
+
+/*
+ * Setup the device for a periodic tick
+ */
+void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
+{
+	tick_set_periodic_handler(dev, broadcast);
+
+	/* Broadcast setup ? */
+	if (!tick_device_is_functional(dev))
+		return;
+
+	if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) &&
+	    !tick_broadcast_oneshot_active()) {
+		clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC);
+	} else {
+		unsigned int seq;
+		ktime_t next;
+
+		do {
+			seq = read_seqcount_begin(&jiffies_seq);
+			next = tick_next_period;
+		} while (read_seqcount_retry(&jiffies_seq, seq));
+
+		clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
+
+		for (;;) {
+			if (!clockevents_program_event(dev, next, false))
+				return;
+			next = ktime_add_ns(next, TICK_NSEC);
+		}
+	}
+}
+
+#ifdef CONFIG_NO_HZ_FULL
+static void giveup_do_timer(void *info)
+{
+	int cpu = *(unsigned int *)info;
+
+	WARN_ON(tick_do_timer_cpu != smp_processor_id());
+
+	tick_do_timer_cpu = cpu;
+}
+
+static void tick_take_do_timer_from_boot(void)
+{
+	int cpu = smp_processor_id();
+	int from = tick_do_timer_boot_cpu;
+
+	if (from >= 0 && from != cpu)
+		smp_call_function_single(from, giveup_do_timer, &cpu, 1);
+}
+#endif
+
+/*
+ * Setup the tick device
+ */
+static void tick_setup_device(struct tick_device *td,
+			      struct clock_event_device *newdev, int cpu,
+			      const struct cpumask *cpumask)
+{
+	void (*handler)(struct clock_event_device *) = NULL;
+	ktime_t next_event = 0;
+
+	/*
+	 * First device setup ?
+	 */
+	if (!td->evtdev) {
+		/*
+		 * If no cpu took the do_timer update, assign it to
+		 * this cpu:
+		 */
+		if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
+			tick_do_timer_cpu = cpu;
+			tick_next_period = ktime_get();
+#ifdef CONFIG_NO_HZ_FULL
+			/*
+			 * The boot CPU may be nohz_full, in which case set
+			 * tick_do_timer_boot_cpu so the first housekeeping
+			 * secondary that comes up will take do_timer from
+			 * us.
+			 */
+			if (tick_nohz_full_cpu(cpu))
+				tick_do_timer_boot_cpu = cpu;
+
+		} else if (tick_do_timer_boot_cpu != -1 &&
+						!tick_nohz_full_cpu(cpu)) {
+			tick_take_do_timer_from_boot();
+			tick_do_timer_boot_cpu = -1;
+			WARN_ON(tick_do_timer_cpu != cpu);
+#endif
+		}
+
+		/*
+		 * Startup in periodic mode first.
+		 */
+		td->mode = TICKDEV_MODE_PERIODIC;
+	} else {
+		handler = td->evtdev->event_handler;
+		next_event = td->evtdev->next_event;
+		td->evtdev->event_handler = clockevents_handle_noop;
+	}
+
+	td->evtdev = newdev;
+
+	/*
+	 * When the device is not per cpu, pin the interrupt to the
+	 * current cpu:
+	 */
+	if (!cpumask_equal(newdev->cpumask, cpumask))
+		irq_set_affinity(newdev->irq, cpumask);
+
+	/*
+	 * When global broadcasting is active, check if the current
+	 * device is registered as a placeholder for broadcast mode.
+	 * This allows us to handle this x86 misfeature in a generic
+	 * way. This function also returns !=0 when we keep the
+	 * current active broadcast state for this CPU.
+	 */
+	if (tick_device_uses_broadcast(newdev, cpu))
+		return;
+
+	if (td->mode == TICKDEV_MODE_PERIODIC)
+		tick_setup_periodic(newdev, 0);
+	else
+		tick_setup_oneshot(newdev, handler, next_event);
+}
+
+void tick_install_replacement(struct clock_event_device *newdev)
+{
+	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+	int cpu = smp_processor_id();
+
+	clockevents_exchange_device(td->evtdev, newdev);
+	tick_setup_device(td, newdev, cpu, cpumask_of(cpu));
+	if (newdev->features & CLOCK_EVT_FEAT_ONESHOT)
+		tick_oneshot_notify();
+}
+
+static bool tick_check_percpu(struct clock_event_device *curdev,
+			      struct clock_event_device *newdev, int cpu)
+{
+	if (!cpumask_test_cpu(cpu, newdev->cpumask))
+		return false;
+	if (cpumask_equal(newdev->cpumask, cpumask_of(cpu)))
+		return true;
+	/* Check if irq affinity can be set */
+	if (newdev->irq >= 0 && !irq_can_set_affinity(newdev->irq))
+		return false;
+	/* Prefer an existing cpu local device */
+	if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu)))
+		return false;
+	return true;
+}
+
+static bool tick_check_preferred(struct clock_event_device *curdev,
+				 struct clock_event_device *newdev)
+{
+	/* Prefer oneshot capable device */
+	if (!(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) {
+		if (curdev && (curdev->features & CLOCK_EVT_FEAT_ONESHOT))
+			return false;
+		if (tick_oneshot_mode_active())
+			return false;
+	}
+
+	/*
+	 * Use the higher rated one, but prefer a CPU local device with a lower
+	 * rating than a non-CPU local device
+	 */
+	return !curdev ||
+		newdev->rating > curdev->rating ||
+	       !cpumask_equal(curdev->cpumask, newdev->cpumask);
+}
+
+/*
+ * Check whether the new device is a better fit than curdev. curdev
+ * can be NULL !
+ */
+bool tick_check_replacement(struct clock_event_device *curdev,
+			    struct clock_event_device *newdev)
+{
+	if (!tick_check_percpu(curdev, newdev, smp_processor_id()))
+		return false;
+
+	return tick_check_preferred(curdev, newdev);
+}
+
+/*
+ * Check, if the new registered device should be used. Called with
+ * clockevents_lock held and interrupts disabled.
+ */
+void tick_check_new_device(struct clock_event_device *newdev)
+{
+	struct clock_event_device *curdev;
+	struct tick_device *td;
+	int cpu;
+
+	cpu = smp_processor_id();
+	td = &per_cpu(tick_cpu_device, cpu);
+	curdev = td->evtdev;
+
+	if (!tick_check_replacement(curdev, newdev))
+		goto out_bc;
+
+	if (!try_module_get(newdev->owner))
+		return;
+
+	/*
+	 * Replace the eventually existing device by the new
+	 * device. If the current device is the broadcast device, do
+	 * not give it back to the clockevents layer !
+	 */
+	if (tick_is_broadcast_device(curdev)) {
+		clockevents_shutdown(curdev);
+		curdev = NULL;
+	}
+	clockevents_exchange_device(curdev, newdev);
+	tick_setup_device(td, newdev, cpu, cpumask_of(cpu));
+	if (newdev->features & CLOCK_EVT_FEAT_ONESHOT)
+		tick_oneshot_notify();
+	return;
+
+out_bc:
+	/*
+	 * Can the new device be used as a broadcast device ?
+	 */
+	tick_install_broadcast_device(newdev, cpu);
+}
+
+/**
+ * tick_broadcast_oneshot_control - Enter/exit broadcast oneshot mode
+ * @state:	The target state (enter/exit)
+ *
+ * The system enters/leaves a state, where affected devices might stop
+ * Returns 0 on success, -EBUSY if the cpu is used to broadcast wakeups.
+ *
+ * Called with interrupts disabled, so clockevents_lock is not
+ * required here because the local clock event device cannot go away
+ * under us.
+ */
+int tick_broadcast_oneshot_control(enum tick_broadcast_state state)
+{
+	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+
+	if (!(td->evtdev->features & CLOCK_EVT_FEAT_C3STOP))
+		return 0;
+
+	return __tick_broadcast_oneshot_control(state);
+}
+EXPORT_SYMBOL_GPL(tick_broadcast_oneshot_control);
+
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * Transfer the do_timer job away from a dying cpu.
+ *
+ * Called with interrupts disabled. No locking required. If
+ * tick_do_timer_cpu is owned by this cpu, nothing can change it.
+ */
+void tick_handover_do_timer(void)
+{
+	if (tick_do_timer_cpu == smp_processor_id())
+		tick_do_timer_cpu = cpumask_first(cpu_online_mask);
+}
+
+/*
+ * Shutdown an event device on a given cpu:
+ *
+ * This is called on a life CPU, when a CPU is dead. So we cannot
+ * access the hardware device itself.
+ * We just set the mode and remove it from the lists.
+ */
+void tick_shutdown(unsigned int cpu)
+{
+	struct tick_device *td = &per_cpu(tick_cpu_device, cpu);
+	struct clock_event_device *dev = td->evtdev;
+
+	td->mode = TICKDEV_MODE_PERIODIC;
+	if (dev) {
+		/*
+		 * Prevent that the clock events layer tries to call
+		 * the set mode function!
+		 */
+		clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED);
+		clockevents_exchange_device(dev, NULL);
+		dev->event_handler = clockevents_handle_noop;
+		td->evtdev = NULL;
+	}
+}
+#endif
+
+/**
+ * tick_suspend_local - Suspend the local tick device
+ *
+ * Called from the local cpu for freeze with interrupts disabled.
+ *
+ * No locks required. Nothing can change the per cpu device.
+ */
+void tick_suspend_local(void)
+{
+	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+
+	clockevents_shutdown(td->evtdev);
+}
+
+/**
+ * tick_resume_local - Resume the local tick device
+ *
+ * Called from the local CPU for unfreeze or XEN resume magic.
+ *
+ * No locks required. Nothing can change the per cpu device.
+ */
+void tick_resume_local(void)
+{
+	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+	bool broadcast = tick_resume_check_broadcast();
+
+	clockevents_tick_resume(td->evtdev);
+	if (!broadcast) {
+		if (td->mode == TICKDEV_MODE_PERIODIC)
+			tick_setup_periodic(td->evtdev, 0);
+		else
+			tick_resume_oneshot();
+	}
+
+	/*
+	 * Ensure that hrtimers are up to date and the clockevents device
+	 * is reprogrammed correctly when high resolution timers are
+	 * enabled.
+	 */
+	hrtimers_resume_local();
+}
+
+/**
+ * tick_suspend - Suspend the tick and the broadcast device
+ *
+ * Called from syscore_suspend() via timekeeping_suspend with only one
+ * CPU online and interrupts disabled or from tick_unfreeze() under
+ * tick_freeze_lock.
+ *
+ * No locks required. Nothing can change the per cpu device.
+ */
+void tick_suspend(void)
+{
+	tick_suspend_local();
+	tick_suspend_broadcast();
+}
+
+/**
+ * tick_resume - Resume the tick and the broadcast device
+ *
+ * Called from syscore_resume() via timekeeping_resume with only one
+ * CPU online and interrupts disabled.
+ *
+ * No locks required. Nothing can change the per cpu device.
+ */
+void tick_resume(void)
+{
+	tick_resume_broadcast();
+	tick_resume_local();
+}
+
+#ifdef CONFIG_SUSPEND
+static DEFINE_RAW_SPINLOCK(tick_freeze_lock);
+static unsigned int tick_freeze_depth;
+
+/**
+ * tick_freeze - Suspend the local tick and (possibly) timekeeping.
+ *
+ * Check if this is the last online CPU executing the function and if so,
+ * suspend timekeeping.  Otherwise suspend the local tick.
+ *
+ * Call with interrupts disabled.  Must be balanced with %tick_unfreeze().
+ * Interrupts must not be enabled before the subsequent %tick_unfreeze().
+ */
+void tick_freeze(void)
+{
+	raw_spin_lock(&tick_freeze_lock);
+
+	tick_freeze_depth++;
+	if (tick_freeze_depth == num_online_cpus()) {
+		trace_suspend_resume(TPS("timekeeping_freeze"),
+				     smp_processor_id(), true);
+		system_state = SYSTEM_SUSPEND;
+		sched_clock_suspend();
+		timekeeping_suspend();
+	} else {
+		tick_suspend_local();
+	}
+
+	raw_spin_unlock(&tick_freeze_lock);
+}
+
+/**
+ * tick_unfreeze - Resume the local tick and (possibly) timekeeping.
+ *
+ * Check if this is the first CPU executing the function and if so, resume
+ * timekeeping.  Otherwise resume the local tick.
+ *
+ * Call with interrupts disabled.  Must be balanced with %tick_freeze().
+ * Interrupts must not be enabled after the preceding %tick_freeze().
+ */
+void tick_unfreeze(void)
+{
+	raw_spin_lock(&tick_freeze_lock);
+
+	if (tick_freeze_depth == num_online_cpus()) {
+		timekeeping_resume();
+		sched_clock_resume();
+		system_state = SYSTEM_RUNNING;
+		trace_suspend_resume(TPS("timekeeping_freeze"),
+				     smp_processor_id(), false);
+	} else {
+		touch_softlockup_watchdog();
+		tick_resume_local();
+	}
+
+	tick_freeze_depth--;
+
+	raw_spin_unlock(&tick_freeze_lock);
+}
+#endif /* CONFIG_SUSPEND */
+
+/**
+ * tick_init - initialize the tick control
+ */
+void __init tick_init(void)
+{
+	tick_broadcast_init();
+	tick_nohz_init();
+}
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
new file mode 100644
index 000000000..649f2b48e
--- /dev/null
+++ b/kernel/time/tick-internal.h
@@ -0,0 +1,199 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * tick internal variable and functions used by low/high res code
+ */
+#include <linux/hrtimer.h>
+#include <linux/tick.h>
+
+#include "timekeeping.h"
+#include "tick-sched.h"
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS
+
+# define TICK_DO_TIMER_NONE	-1
+# define TICK_DO_TIMER_BOOT	-2
+
+DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
+extern ktime_t tick_next_period;
+extern int tick_do_timer_cpu __read_mostly;
+
+extern void tick_setup_periodic(struct clock_event_device *dev, int broadcast);
+extern void tick_handle_periodic(struct clock_event_device *dev);
+extern void tick_check_new_device(struct clock_event_device *dev);
+extern void tick_shutdown(unsigned int cpu);
+extern void tick_suspend(void);
+extern void tick_resume(void);
+extern bool tick_check_replacement(struct clock_event_device *curdev,
+				   struct clock_event_device *newdev);
+extern void tick_install_replacement(struct clock_event_device *dev);
+extern int tick_is_oneshot_available(void);
+extern struct tick_device *tick_get_device(int cpu);
+
+extern int clockevents_tick_resume(struct clock_event_device *dev);
+/* Check, if the device is functional or a dummy for broadcast */
+static inline int tick_device_is_functional(struct clock_event_device *dev)
+{
+	return !(dev->features & CLOCK_EVT_FEAT_DUMMY);
+}
+
+static inline enum clock_event_state clockevent_get_state(struct clock_event_device *dev)
+{
+	return dev->state_use_accessors;
+}
+
+static inline void clockevent_set_state(struct clock_event_device *dev,
+					enum clock_event_state state)
+{
+	dev->state_use_accessors = state;
+}
+
+extern void clockevents_shutdown(struct clock_event_device *dev);
+extern void clockevents_exchange_device(struct clock_event_device *old,
+					struct clock_event_device *new);
+extern void clockevents_switch_state(struct clock_event_device *dev,
+				     enum clock_event_state state);
+extern int clockevents_program_event(struct clock_event_device *dev,
+				     ktime_t expires, bool force);
+extern void clockevents_handle_noop(struct clock_event_device *dev);
+extern int __clockevents_update_freq(struct clock_event_device *dev, u32 freq);
+extern ssize_t sysfs_get_uname(const char *buf, char *dst, size_t cnt);
+
+/* Broadcasting support */
+# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+extern int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu);
+extern void tick_install_broadcast_device(struct clock_event_device *dev, int cpu);
+extern int tick_is_broadcast_device(struct clock_event_device *dev);
+extern void tick_suspend_broadcast(void);
+extern void tick_resume_broadcast(void);
+extern bool tick_resume_check_broadcast(void);
+extern void tick_broadcast_init(void);
+extern void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast);
+extern int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq);
+extern struct tick_device *tick_get_broadcast_device(void);
+extern struct cpumask *tick_get_broadcast_mask(void);
+extern const struct clock_event_device *tick_get_wakeup_device(int cpu);
+# else /* !CONFIG_GENERIC_CLOCKEVENTS_BROADCAST: */
+static inline void tick_install_broadcast_device(struct clock_event_device *dev, int cpu) { }
+static inline int tick_is_broadcast_device(struct clock_event_device *dev) { return 0; }
+static inline int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) { return 0; }
+static inline void tick_do_periodic_broadcast(struct clock_event_device *d) { }
+static inline void tick_suspend_broadcast(void) { }
+static inline void tick_resume_broadcast(void) { }
+static inline bool tick_resume_check_broadcast(void) { return false; }
+static inline void tick_broadcast_init(void) { }
+static inline int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq) { return -ENODEV; }
+
+/* Set the periodic handler in non broadcast mode */
+static inline void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
+{
+	dev->event_handler = tick_handle_periodic;
+}
+# endif /* !CONFIG_GENERIC_CLOCKEVENTS_BROADCAST */
+
+#else /* !GENERIC_CLOCKEVENTS: */
+static inline void tick_suspend(void) { }
+static inline void tick_resume(void) { }
+#endif /* !GENERIC_CLOCKEVENTS */
+
+/* Oneshot related functions */
+#ifdef CONFIG_TICK_ONESHOT
+extern void tick_setup_oneshot(struct clock_event_device *newdev,
+			       void (*handler)(struct clock_event_device *),
+			       ktime_t nextevt);
+extern int tick_program_event(ktime_t expires, int force);
+extern void tick_oneshot_notify(void);
+extern int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *));
+extern void tick_resume_oneshot(void);
+static inline bool tick_oneshot_possible(void) { return true; }
+extern int tick_oneshot_mode_active(void);
+extern void tick_clock_notify(void);
+extern int tick_check_oneshot_change(int allow_nohz);
+extern int tick_init_highres(void);
+#else /* !CONFIG_TICK_ONESHOT: */
+static inline
+void tick_setup_oneshot(struct clock_event_device *newdev,
+			void (*handler)(struct clock_event_device *),
+			ktime_t nextevt) { BUG(); }
+static inline void tick_resume_oneshot(void) { BUG(); }
+static inline int tick_program_event(ktime_t expires, int force) { return 0; }
+static inline void tick_oneshot_notify(void) { }
+static inline bool tick_oneshot_possible(void) { return false; }
+static inline int tick_oneshot_mode_active(void) { return 0; }
+static inline void tick_clock_notify(void) { }
+static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
+#endif /* !CONFIG_TICK_ONESHOT */
+
+/* Functions related to oneshot broadcasting */
+#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
+extern void tick_broadcast_switch_to_oneshot(void);
+extern int tick_broadcast_oneshot_active(void);
+extern void tick_check_oneshot_broadcast_this_cpu(void);
+bool tick_broadcast_oneshot_available(void);
+extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
+#else /* !(BROADCAST && ONESHOT): */
+static inline void tick_broadcast_switch_to_oneshot(void) { }
+static inline int tick_broadcast_oneshot_active(void) { return 0; }
+static inline void tick_check_oneshot_broadcast_this_cpu(void) { }
+static inline bool tick_broadcast_oneshot_available(void) { return tick_oneshot_possible(); }
+#endif /* !(BROADCAST && ONESHOT) */
+
+#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_HOTPLUG_CPU)
+extern void tick_broadcast_offline(unsigned int cpu);
+#else
+static inline void tick_broadcast_offline(unsigned int cpu) { }
+#endif
+
+/* NO_HZ_FULL internal */
+#ifdef CONFIG_NO_HZ_FULL
+extern void tick_nohz_init(void);
+# else
+static inline void tick_nohz_init(void) { }
+#endif
+
+#ifdef CONFIG_NO_HZ_COMMON
+extern unsigned long tick_nohz_active;
+extern void timers_update_nohz(void);
+# ifdef CONFIG_SMP
+extern struct static_key_false timers_migration_enabled;
+# endif
+#else /* CONFIG_NO_HZ_COMMON */
+static inline void timers_update_nohz(void) { }
+#define tick_nohz_active (0)
+#endif
+
+DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
+
+extern u64 get_next_timer_interrupt(unsigned long basej, u64 basem);
+void timer_clear_idle(void);
+
+#define CLOCK_SET_WALL							\
+	(BIT(HRTIMER_BASE_REALTIME) | BIT(HRTIMER_BASE_REALTIME_SOFT) |	\
+	 BIT(HRTIMER_BASE_TAI) | BIT(HRTIMER_BASE_TAI_SOFT))
+
+#define CLOCK_SET_BOOT							\
+	(BIT(HRTIMER_BASE_BOOTTIME) | BIT(HRTIMER_BASE_BOOTTIME_SOFT))
+
+void clock_was_set(unsigned int bases);
+void clock_was_set_delayed(void);
+
+void hrtimers_resume_local(void);
+
+/* Since jiffies uses a simple TICK_NSEC multiplier
+ * conversion, the .shift value could be zero. However
+ * this would make NTP adjustments impossible as they are
+ * in units of 1/2^.shift. Thus we use JIFFIES_SHIFT to
+ * shift both the nominator and denominator the same
+ * amount, and give ntp adjustments in units of 1/2^8
+ *
+ * The value 8 is somewhat carefully chosen, as anything
+ * larger can result in overflows. TICK_NSEC grows as HZ
+ * shrinks, so values greater than 8 overflow 32bits when
+ * HZ=100.
+ */
+#if HZ < 34
+#define JIFFIES_SHIFT	6
+#elif HZ < 67
+#define JIFFIES_SHIFT	7
+#else
+#define JIFFIES_SHIFT	8
+#endif
diff --git a/kernel/time/tick-legacy.c b/kernel/time/tick-legacy.c
new file mode 100644
index 000000000..af225b32f
--- /dev/null
+++ b/kernel/time/tick-legacy.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Timer tick function for architectures that lack generic clockevents,
+ * consolidated here from m68k/ia64/parisc/arm.
+ */
+
+#include <linux/irq.h>
+#include <linux/profile.h>
+#include <linux/timekeeper_internal.h>
+
+#include "tick-internal.h"
+
+/**
+ * legacy_timer_tick() - advances the timekeeping infrastructure
+ * @ticks:	number of ticks, that have elapsed since the last call.
+ *
+ * This is used by platforms that have not been converted to
+ * generic clockevents.
+ *
+ * If 'ticks' is zero, the CPU is not handling timekeeping, so
+ * only perform process accounting and profiling.
+ *
+ * Must be called with interrupts disabled.
+ */
+void legacy_timer_tick(unsigned long ticks)
+{
+	if (ticks) {
+		raw_spin_lock(&jiffies_lock);
+		write_seqcount_begin(&jiffies_seq);
+		do_timer(ticks);
+		write_seqcount_end(&jiffies_seq);
+		raw_spin_unlock(&jiffies_lock);
+		update_wall_time();
+	}
+	update_process_times(user_mode(get_irq_regs()));
+	profile_tick(CPU_PROFILING);
+}
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
new file mode 100644
index 000000000..475ecceda
--- /dev/null
+++ b/kernel/time/tick-oneshot.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file contains functions which manage high resolution tick
+ * related events.
+ *
+ * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
+ * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
+ * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
+ */
+#include <linux/cpu.h>
+#include <linux/err.h>
+#include <linux/hrtimer.h>
+#include <linux/interrupt.h>
+#include <linux/percpu.h>
+#include <linux/profile.h>
+#include <linux/sched.h>
+
+#include "tick-internal.h"
+
+/**
+ * tick_program_event
+ */
+int tick_program_event(ktime_t expires, int force)
+{
+	struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
+
+	if (unlikely(expires == KTIME_MAX)) {
+		/*
+		 * We don't need the clock event device any more, stop it.
+		 */
+		clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT_STOPPED);
+		dev->next_event = KTIME_MAX;
+		return 0;
+	}
+
+	if (unlikely(clockevent_state_oneshot_stopped(dev))) {
+		/*
+		 * We need the clock event again, configure it in ONESHOT mode
+		 * before using it.
+		 */
+		clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
+	}
+
+	return clockevents_program_event(dev, expires, force);
+}
+
+/**
+ * tick_resume_oneshot - resume oneshot mode
+ */
+void tick_resume_oneshot(void)
+{
+	struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
+
+	clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
+	clockevents_program_event(dev, ktime_get(), true);
+}
+
+/**
+ * tick_setup_oneshot - setup the event device for oneshot mode (hres or nohz)
+ */
+void tick_setup_oneshot(struct clock_event_device *newdev,
+			void (*handler)(struct clock_event_device *),
+			ktime_t next_event)
+{
+	newdev->event_handler = handler;
+	clockevents_switch_state(newdev, CLOCK_EVT_STATE_ONESHOT);
+	clockevents_program_event(newdev, next_event, true);
+}
+
+/**
+ * tick_switch_to_oneshot - switch to oneshot mode
+ */
+int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *))
+{
+	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+	struct clock_event_device *dev = td->evtdev;
+
+	if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT) ||
+		    !tick_device_is_functional(dev)) {
+
+		pr_info("Clockevents: could not switch to one-shot mode:");
+		if (!dev) {
+			pr_cont(" no tick device\n");
+		} else {
+			if (!tick_device_is_functional(dev))
+				pr_cont(" %s is not functional.\n", dev->name);
+			else
+				pr_cont(" %s does not support one-shot mode.\n",
+					dev->name);
+		}
+		return -EINVAL;
+	}
+
+	td->mode = TICKDEV_MODE_ONESHOT;
+	dev->event_handler = handler;
+	clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
+	tick_broadcast_switch_to_oneshot();
+	return 0;
+}
+
+/**
+ * tick_check_oneshot_mode - check whether the system is in oneshot mode
+ *
+ * returns 1 when either nohz or highres are enabled. otherwise 0.
+ */
+int tick_oneshot_mode_active(void)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+	ret = __this_cpu_read(tick_cpu_device.mode) == TICKDEV_MODE_ONESHOT;
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+#ifdef CONFIG_HIGH_RES_TIMERS
+/**
+ * tick_init_highres - switch to high resolution mode
+ *
+ * Called with interrupts disabled.
+ */
+int tick_init_highres(void)
+{
+	return tick_switch_to_oneshot(hrtimer_interrupt);
+}
+#endif
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
new file mode 100644
index 000000000..8cfdc6b97
--- /dev/null
+++ b/kernel/time/tick-sched.c
@@ -0,0 +1,1626 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
+ *  Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
+ *  Copyright(C) 2006-2007  Timesys Corp., Thomas Gleixner
+ *
+ *  No idle tick implementation for low and high resolution timers
+ *
+ *  Started by: Thomas Gleixner and Ingo Molnar
+ */
+#include <linux/cpu.h>
+#include <linux/err.h>
+#include <linux/hrtimer.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+#include <linux/percpu.h>
+#include <linux/nmi.h>
+#include <linux/profile.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/stat.h>
+#include <linux/sched/nohz.h>
+#include <linux/sched/loadavg.h>
+#include <linux/module.h>
+#include <linux/irq_work.h>
+#include <linux/posix-timers.h>
+#include <linux/context_tracking.h>
+#include <linux/mm.h>
+
+#include <asm/irq_regs.h>
+
+#include "tick-internal.h"
+
+#include <trace/events/timer.h>
+
+/*
+ * Per-CPU nohz control structure
+ */
+static DEFINE_PER_CPU(struct tick_sched, tick_cpu_sched);
+
+struct tick_sched *tick_get_tick_sched(int cpu)
+{
+	return &per_cpu(tick_cpu_sched, cpu);
+}
+
+#if defined(CONFIG_NO_HZ_COMMON) || defined(CONFIG_HIGH_RES_TIMERS)
+/*
+ * The time, when the last jiffy update happened. Write access must hold
+ * jiffies_lock and jiffies_seq. tick_nohz_next_event() needs to get a
+ * consistent view of jiffies and last_jiffies_update.
+ */
+static ktime_t last_jiffies_update;
+
+/*
+ * Must be called with interrupts disabled !
+ */
+static void tick_do_update_jiffies64(ktime_t now)
+{
+	unsigned long ticks = 1;
+	ktime_t delta, nextp;
+
+	/*
+	 * 64bit can do a quick check without holding jiffies lock and
+	 * without looking at the sequence count. The smp_load_acquire()
+	 * pairs with the update done later in this function.
+	 *
+	 * 32bit cannot do that because the store of tick_next_period
+	 * consists of two 32bit stores and the first store could move it
+	 * to a random point in the future.
+	 */
+	if (IS_ENABLED(CONFIG_64BIT)) {
+		if (ktime_before(now, smp_load_acquire(&tick_next_period)))
+			return;
+	} else {
+		unsigned int seq;
+
+		/*
+		 * Avoid contention on jiffies_lock and protect the quick
+		 * check with the sequence count.
+		 */
+		do {
+			seq = read_seqcount_begin(&jiffies_seq);
+			nextp = tick_next_period;
+		} while (read_seqcount_retry(&jiffies_seq, seq));
+
+		if (ktime_before(now, nextp))
+			return;
+	}
+
+	/* Quick check failed, i.e. update is required. */
+	raw_spin_lock(&jiffies_lock);
+	/*
+	 * Reevaluate with the lock held. Another CPU might have done the
+	 * update already.
+	 */
+	if (ktime_before(now, tick_next_period)) {
+		raw_spin_unlock(&jiffies_lock);
+		return;
+	}
+
+	write_seqcount_begin(&jiffies_seq);
+
+	delta = ktime_sub(now, tick_next_period);
+	if (unlikely(delta >= TICK_NSEC)) {
+		/* Slow path for long idle sleep times */
+		s64 incr = TICK_NSEC;
+
+		ticks += ktime_divns(delta, incr);
+
+		last_jiffies_update = ktime_add_ns(last_jiffies_update,
+						   incr * ticks);
+	} else {
+		last_jiffies_update = ktime_add_ns(last_jiffies_update,
+						   TICK_NSEC);
+	}
+
+	/* Advance jiffies to complete the jiffies_seq protected job */
+	jiffies_64 += ticks;
+
+	/*
+	 * Keep the tick_next_period variable up to date.
+	 */
+	nextp = ktime_add_ns(last_jiffies_update, TICK_NSEC);
+
+	if (IS_ENABLED(CONFIG_64BIT)) {
+		/*
+		 * Pairs with smp_load_acquire() in the lockless quick
+		 * check above and ensures that the update to jiffies_64 is
+		 * not reordered vs. the store to tick_next_period, neither
+		 * by the compiler nor by the CPU.
+		 */
+		smp_store_release(&tick_next_period, nextp);
+	} else {
+		/*
+		 * A plain store is good enough on 32bit as the quick check
+		 * above is protected by the sequence count.
+		 */
+		tick_next_period = nextp;
+	}
+
+	/*
+	 * Release the sequence count. calc_global_load() below is not
+	 * protected by it, but jiffies_lock needs to be held to prevent
+	 * concurrent invocations.
+	 */
+	write_seqcount_end(&jiffies_seq);
+
+	calc_global_load();
+
+	raw_spin_unlock(&jiffies_lock);
+	update_wall_time();
+}
+
+/*
+ * Initialize and return retrieve the jiffies update.
+ */
+static ktime_t tick_init_jiffy_update(void)
+{
+	ktime_t period;
+
+	raw_spin_lock(&jiffies_lock);
+	write_seqcount_begin(&jiffies_seq);
+	/* Did we start the jiffies update yet ? */
+	if (last_jiffies_update == 0) {
+		u32 rem;
+
+		/*
+		 * Ensure that the tick is aligned to a multiple of
+		 * TICK_NSEC.
+		 */
+		div_u64_rem(tick_next_period, TICK_NSEC, &rem);
+		if (rem)
+			tick_next_period += TICK_NSEC - rem;
+
+		last_jiffies_update = tick_next_period;
+	}
+	period = last_jiffies_update;
+	write_seqcount_end(&jiffies_seq);
+	raw_spin_unlock(&jiffies_lock);
+	return period;
+}
+
+#define MAX_STALLED_JIFFIES 5
+
+static void tick_sched_do_timer(struct tick_sched *ts, ktime_t now)
+{
+	int cpu = smp_processor_id();
+
+#ifdef CONFIG_NO_HZ_COMMON
+	/*
+	 * Check if the do_timer duty was dropped. We don't care about
+	 * concurrency: This happens only when the CPU in charge went
+	 * into a long sleep. If two CPUs happen to assign themselves to
+	 * this duty, then the jiffies update is still serialized by
+	 * jiffies_lock.
+	 *
+	 * If nohz_full is enabled, this should not happen because the
+	 * tick_do_timer_cpu never relinquishes.
+	 */
+	if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE)) {
+#ifdef CONFIG_NO_HZ_FULL
+		WARN_ON_ONCE(tick_nohz_full_running);
+#endif
+		tick_do_timer_cpu = cpu;
+	}
+#endif
+
+	/* Check, if the jiffies need an update */
+	if (tick_do_timer_cpu == cpu)
+		tick_do_update_jiffies64(now);
+
+	/*
+	 * If jiffies update stalled for too long (timekeeper in stop_machine()
+	 * or VMEXIT'ed for several msecs), force an update.
+	 */
+	if (ts->last_tick_jiffies != jiffies) {
+		ts->stalled_jiffies = 0;
+		ts->last_tick_jiffies = READ_ONCE(jiffies);
+	} else {
+		if (++ts->stalled_jiffies == MAX_STALLED_JIFFIES) {
+			tick_do_update_jiffies64(now);
+			ts->stalled_jiffies = 0;
+			ts->last_tick_jiffies = READ_ONCE(jiffies);
+		}
+	}
+
+	if (ts->inidle)
+		ts->got_idle_tick = 1;
+}
+
+static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
+{
+#ifdef CONFIG_NO_HZ_COMMON
+	/*
+	 * When we are idle and the tick is stopped, we have to touch
+	 * the watchdog as we might not schedule for a really long
+	 * time. This happens on complete idle SMP systems while
+	 * waiting on the login prompt. We also increment the "start of
+	 * idle" jiffy stamp so the idle accounting adjustment we do
+	 * when we go busy again does not account too much ticks.
+	 */
+	if (ts->tick_stopped) {
+		touch_softlockup_watchdog_sched();
+		if (is_idle_task(current))
+			ts->idle_jiffies++;
+		/*
+		 * In case the current tick fired too early past its expected
+		 * expiration, make sure we don't bypass the next clock reprogramming
+		 * to the same deadline.
+		 */
+		ts->next_tick = 0;
+	}
+#endif
+	update_process_times(user_mode(regs));
+	profile_tick(CPU_PROFILING);
+}
+#endif
+
+#ifdef CONFIG_NO_HZ_FULL
+cpumask_var_t tick_nohz_full_mask;
+EXPORT_SYMBOL_GPL(tick_nohz_full_mask);
+bool tick_nohz_full_running;
+EXPORT_SYMBOL_GPL(tick_nohz_full_running);
+static atomic_t tick_dep_mask;
+
+static bool check_tick_dependency(atomic_t *dep)
+{
+	int val = atomic_read(dep);
+
+	if (val & TICK_DEP_MASK_POSIX_TIMER) {
+		trace_tick_stop(0, TICK_DEP_MASK_POSIX_TIMER);
+		return true;
+	}
+
+	if (val & TICK_DEP_MASK_PERF_EVENTS) {
+		trace_tick_stop(0, TICK_DEP_MASK_PERF_EVENTS);
+		return true;
+	}
+
+	if (val & TICK_DEP_MASK_SCHED) {
+		trace_tick_stop(0, TICK_DEP_MASK_SCHED);
+		return true;
+	}
+
+	if (val & TICK_DEP_MASK_CLOCK_UNSTABLE) {
+		trace_tick_stop(0, TICK_DEP_MASK_CLOCK_UNSTABLE);
+		return true;
+	}
+
+	if (val & TICK_DEP_MASK_RCU) {
+		trace_tick_stop(0, TICK_DEP_MASK_RCU);
+		return true;
+	}
+
+	if (val & TICK_DEP_MASK_RCU_EXP) {
+		trace_tick_stop(0, TICK_DEP_MASK_RCU_EXP);
+		return true;
+	}
+
+	return false;
+}
+
+static bool can_stop_full_tick(int cpu, struct tick_sched *ts)
+{
+	lockdep_assert_irqs_disabled();
+
+	if (unlikely(!cpu_online(cpu)))
+		return false;
+
+	if (check_tick_dependency(&tick_dep_mask))
+		return false;
+
+	if (check_tick_dependency(&ts->tick_dep_mask))
+		return false;
+
+	if (check_tick_dependency(&current->tick_dep_mask))
+		return false;
+
+	if (check_tick_dependency(&current->signal->tick_dep_mask))
+		return false;
+
+	return true;
+}
+
+static void nohz_full_kick_func(struct irq_work *work)
+{
+	/* Empty, the tick restart happens on tick_nohz_irq_exit() */
+}
+
+static DEFINE_PER_CPU(struct irq_work, nohz_full_kick_work) =
+	IRQ_WORK_INIT_HARD(nohz_full_kick_func);
+
+/*
+ * Kick this CPU if it's full dynticks in order to force it to
+ * re-evaluate its dependency on the tick and restart it if necessary.
+ * This kick, unlike tick_nohz_full_kick_cpu() and tick_nohz_full_kick_all(),
+ * is NMI safe.
+ */
+static void tick_nohz_full_kick(void)
+{
+	if (!tick_nohz_full_cpu(smp_processor_id()))
+		return;
+
+	irq_work_queue(this_cpu_ptr(&nohz_full_kick_work));
+}
+
+/*
+ * Kick the CPU if it's full dynticks in order to force it to
+ * re-evaluate its dependency on the tick and restart it if necessary.
+ */
+void tick_nohz_full_kick_cpu(int cpu)
+{
+	if (!tick_nohz_full_cpu(cpu))
+		return;
+
+	irq_work_queue_on(&per_cpu(nohz_full_kick_work, cpu), cpu);
+}
+
+static void tick_nohz_kick_task(struct task_struct *tsk)
+{
+	int cpu;
+
+	/*
+	 * If the task is not running, run_posix_cpu_timers()
+	 * has nothing to elapse, IPI can then be spared.
+	 *
+	 * activate_task()                      STORE p->tick_dep_mask
+	 *   STORE p->on_rq
+	 * __schedule() (switch to task 'p')    smp_mb() (atomic_fetch_or())
+	 *   LOCK rq->lock                      LOAD p->on_rq
+	 *   smp_mb__after_spin_lock()
+	 *   tick_nohz_task_switch()
+	 *     LOAD p->tick_dep_mask
+	 */
+	if (!sched_task_on_rq(tsk))
+		return;
+
+	/*
+	 * If the task concurrently migrates to another CPU,
+	 * we guarantee it sees the new tick dependency upon
+	 * schedule.
+	 *
+	 * set_task_cpu(p, cpu);
+	 *   STORE p->cpu = @cpu
+	 * __schedule() (switch to task 'p')
+	 *   LOCK rq->lock
+	 *   smp_mb__after_spin_lock()          STORE p->tick_dep_mask
+	 *   tick_nohz_task_switch()            smp_mb() (atomic_fetch_or())
+	 *      LOAD p->tick_dep_mask           LOAD p->cpu
+	 */
+	cpu = task_cpu(tsk);
+
+	preempt_disable();
+	if (cpu_online(cpu))
+		tick_nohz_full_kick_cpu(cpu);
+	preempt_enable();
+}
+
+/*
+ * Kick all full dynticks CPUs in order to force these to re-evaluate
+ * their dependency on the tick and restart it if necessary.
+ */
+static void tick_nohz_full_kick_all(void)
+{
+	int cpu;
+
+	if (!tick_nohz_full_running)
+		return;
+
+	preempt_disable();
+	for_each_cpu_and(cpu, tick_nohz_full_mask, cpu_online_mask)
+		tick_nohz_full_kick_cpu(cpu);
+	preempt_enable();
+}
+
+static void tick_nohz_dep_set_all(atomic_t *dep,
+				  enum tick_dep_bits bit)
+{
+	int prev;
+
+	prev = atomic_fetch_or(BIT(bit), dep);
+	if (!prev)
+		tick_nohz_full_kick_all();
+}
+
+/*
+ * Set a global tick dependency. Used by perf events that rely on freq and
+ * by unstable clock.
+ */
+void tick_nohz_dep_set(enum tick_dep_bits bit)
+{
+	tick_nohz_dep_set_all(&tick_dep_mask, bit);
+}
+
+void tick_nohz_dep_clear(enum tick_dep_bits bit)
+{
+	atomic_andnot(BIT(bit), &tick_dep_mask);
+}
+
+/*
+ * Set per-CPU tick dependency. Used by scheduler and perf events in order to
+ * manage events throttling.
+ */
+void tick_nohz_dep_set_cpu(int cpu, enum tick_dep_bits bit)
+{
+	int prev;
+	struct tick_sched *ts;
+
+	ts = per_cpu_ptr(&tick_cpu_sched, cpu);
+
+	prev = atomic_fetch_or(BIT(bit), &ts->tick_dep_mask);
+	if (!prev) {
+		preempt_disable();
+		/* Perf needs local kick that is NMI safe */
+		if (cpu == smp_processor_id()) {
+			tick_nohz_full_kick();
+		} else {
+			/* Remote irq work not NMI-safe */
+			if (!WARN_ON_ONCE(in_nmi()))
+				tick_nohz_full_kick_cpu(cpu);
+		}
+		preempt_enable();
+	}
+}
+EXPORT_SYMBOL_GPL(tick_nohz_dep_set_cpu);
+
+void tick_nohz_dep_clear_cpu(int cpu, enum tick_dep_bits bit)
+{
+	struct tick_sched *ts = per_cpu_ptr(&tick_cpu_sched, cpu);
+
+	atomic_andnot(BIT(bit), &ts->tick_dep_mask);
+}
+EXPORT_SYMBOL_GPL(tick_nohz_dep_clear_cpu);
+
+/*
+ * Set a per-task tick dependency. RCU need this. Also posix CPU timers
+ * in order to elapse per task timers.
+ */
+void tick_nohz_dep_set_task(struct task_struct *tsk, enum tick_dep_bits bit)
+{
+	if (!atomic_fetch_or(BIT(bit), &tsk->tick_dep_mask))
+		tick_nohz_kick_task(tsk);
+}
+EXPORT_SYMBOL_GPL(tick_nohz_dep_set_task);
+
+void tick_nohz_dep_clear_task(struct task_struct *tsk, enum tick_dep_bits bit)
+{
+	atomic_andnot(BIT(bit), &tsk->tick_dep_mask);
+}
+EXPORT_SYMBOL_GPL(tick_nohz_dep_clear_task);
+
+/*
+ * Set a per-taskgroup tick dependency. Posix CPU timers need this in order to elapse
+ * per process timers.
+ */
+void tick_nohz_dep_set_signal(struct task_struct *tsk,
+			      enum tick_dep_bits bit)
+{
+	int prev;
+	struct signal_struct *sig = tsk->signal;
+
+	prev = atomic_fetch_or(BIT(bit), &sig->tick_dep_mask);
+	if (!prev) {
+		struct task_struct *t;
+
+		lockdep_assert_held(&tsk->sighand->siglock);
+		__for_each_thread(sig, t)
+			tick_nohz_kick_task(t);
+	}
+}
+
+void tick_nohz_dep_clear_signal(struct signal_struct *sig, enum tick_dep_bits bit)
+{
+	atomic_andnot(BIT(bit), &sig->tick_dep_mask);
+}
+
+/*
+ * Re-evaluate the need for the tick as we switch the current task.
+ * It might need the tick due to per task/process properties:
+ * perf events, posix CPU timers, ...
+ */
+void __tick_nohz_task_switch(void)
+{
+	struct tick_sched *ts;
+
+	if (!tick_nohz_full_cpu(smp_processor_id()))
+		return;
+
+	ts = this_cpu_ptr(&tick_cpu_sched);
+
+	if (ts->tick_stopped) {
+		if (atomic_read(&current->tick_dep_mask) ||
+		    atomic_read(&current->signal->tick_dep_mask))
+			tick_nohz_full_kick();
+	}
+}
+
+/* Get the boot-time nohz CPU list from the kernel parameters. */
+void __init tick_nohz_full_setup(cpumask_var_t cpumask)
+{
+	alloc_bootmem_cpumask_var(&tick_nohz_full_mask);
+	cpumask_copy(tick_nohz_full_mask, cpumask);
+	tick_nohz_full_running = true;
+}
+
+bool tick_nohz_cpu_hotpluggable(unsigned int cpu)
+{
+	/*
+	 * The tick_do_timer_cpu CPU handles housekeeping duty (unbound
+	 * timers, workqueues, timekeeping, ...) on behalf of full dynticks
+	 * CPUs. It must remain online when nohz full is enabled.
+	 */
+	if (tick_nohz_full_running && tick_do_timer_cpu == cpu)
+		return false;
+	return true;
+}
+
+static int tick_nohz_cpu_down(unsigned int cpu)
+{
+	return tick_nohz_cpu_hotpluggable(cpu) ? 0 : -EBUSY;
+}
+
+void __init tick_nohz_init(void)
+{
+	int cpu, ret;
+
+	if (!tick_nohz_full_running)
+		return;
+
+	/*
+	 * Full dynticks uses irq work to drive the tick rescheduling on safe
+	 * locking contexts. But then we need irq work to raise its own
+	 * interrupts to avoid circular dependency on the tick
+	 */
+	if (!arch_irq_work_has_interrupt()) {
+		pr_warn("NO_HZ: Can't run full dynticks because arch doesn't support irq work self-IPIs\n");
+		cpumask_clear(tick_nohz_full_mask);
+		tick_nohz_full_running = false;
+		return;
+	}
+
+	if (IS_ENABLED(CONFIG_PM_SLEEP_SMP) &&
+			!IS_ENABLED(CONFIG_PM_SLEEP_SMP_NONZERO_CPU)) {
+		cpu = smp_processor_id();
+
+		if (cpumask_test_cpu(cpu, tick_nohz_full_mask)) {
+			pr_warn("NO_HZ: Clearing %d from nohz_full range "
+				"for timekeeping\n", cpu);
+			cpumask_clear_cpu(cpu, tick_nohz_full_mask);
+		}
+	}
+
+	for_each_cpu(cpu, tick_nohz_full_mask)
+		ct_cpu_track_user(cpu);
+
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+					"kernel/nohz:predown", NULL,
+					tick_nohz_cpu_down);
+	WARN_ON(ret < 0);
+	pr_info("NO_HZ: Full dynticks CPUs: %*pbl.\n",
+		cpumask_pr_args(tick_nohz_full_mask));
+}
+#endif
+
+/*
+ * NOHZ - aka dynamic tick functionality
+ */
+#ifdef CONFIG_NO_HZ_COMMON
+/*
+ * NO HZ enabled ?
+ */
+bool tick_nohz_enabled __read_mostly  = true;
+unsigned long tick_nohz_active  __read_mostly;
+/*
+ * Enable / Disable tickless mode
+ */
+static int __init setup_tick_nohz(char *str)
+{
+	return (kstrtobool(str, &tick_nohz_enabled) == 0);
+}
+
+__setup("nohz=", setup_tick_nohz);
+
+bool tick_nohz_tick_stopped(void)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+
+	return ts->tick_stopped;
+}
+
+bool tick_nohz_tick_stopped_cpu(int cpu)
+{
+	struct tick_sched *ts = per_cpu_ptr(&tick_cpu_sched, cpu);
+
+	return ts->tick_stopped;
+}
+
+/**
+ * tick_nohz_update_jiffies - update jiffies when idle was interrupted
+ *
+ * Called from interrupt entry when the CPU was idle
+ *
+ * In case the sched_tick was stopped on this CPU, we have to check if jiffies
+ * must be updated. Otherwise an interrupt handler could use a stale jiffy
+ * value. We do this unconditionally on any CPU, as we don't know whether the
+ * CPU, which has the update task assigned is in a long sleep.
+ */
+static void tick_nohz_update_jiffies(ktime_t now)
+{
+	unsigned long flags;
+
+	__this_cpu_write(tick_cpu_sched.idle_waketime, now);
+
+	local_irq_save(flags);
+	tick_do_update_jiffies64(now);
+	local_irq_restore(flags);
+
+	touch_softlockup_watchdog_sched();
+}
+
+/*
+ * Updates the per-CPU time idle statistics counters
+ */
+static void
+update_ts_time_stats(int cpu, struct tick_sched *ts, ktime_t now, u64 *last_update_time)
+{
+	ktime_t delta;
+
+	if (ts->idle_active) {
+		delta = ktime_sub(now, ts->idle_entrytime);
+		if (nr_iowait_cpu(cpu) > 0)
+			ts->iowait_sleeptime = ktime_add(ts->iowait_sleeptime, delta);
+		else
+			ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
+		ts->idle_entrytime = now;
+	}
+
+	if (last_update_time)
+		*last_update_time = ktime_to_us(now);
+
+}
+
+static void tick_nohz_stop_idle(struct tick_sched *ts, ktime_t now)
+{
+	update_ts_time_stats(smp_processor_id(), ts, now, NULL);
+	ts->idle_active = 0;
+
+	sched_clock_idle_wakeup_event();
+}
+
+static void tick_nohz_start_idle(struct tick_sched *ts)
+{
+	ts->idle_entrytime = ktime_get();
+	ts->idle_active = 1;
+	sched_clock_idle_sleep_event();
+}
+
+/**
+ * get_cpu_idle_time_us - get the total idle time of a CPU
+ * @cpu: CPU number to query
+ * @last_update_time: variable to store update time in. Do not update
+ * counters if NULL.
+ *
+ * Return the cumulative idle time (since boot) for a given
+ * CPU, in microseconds.
+ *
+ * This time is measured via accounting rather than sampling,
+ * and is as accurate as ktime_get() is.
+ *
+ * This function returns -1 if NOHZ is not enabled.
+ */
+u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
+{
+	struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+	ktime_t now, idle;
+
+	if (!tick_nohz_active)
+		return -1;
+
+	now = ktime_get();
+	if (last_update_time) {
+		update_ts_time_stats(cpu, ts, now, last_update_time);
+		idle = ts->idle_sleeptime;
+	} else {
+		if (ts->idle_active && !nr_iowait_cpu(cpu)) {
+			ktime_t delta = ktime_sub(now, ts->idle_entrytime);
+
+			idle = ktime_add(ts->idle_sleeptime, delta);
+		} else {
+			idle = ts->idle_sleeptime;
+		}
+	}
+
+	return ktime_to_us(idle);
+
+}
+EXPORT_SYMBOL_GPL(get_cpu_idle_time_us);
+
+/**
+ * get_cpu_iowait_time_us - get the total iowait time of a CPU
+ * @cpu: CPU number to query
+ * @last_update_time: variable to store update time in. Do not update
+ * counters if NULL.
+ *
+ * Return the cumulative iowait time (since boot) for a given
+ * CPU, in microseconds.
+ *
+ * This time is measured via accounting rather than sampling,
+ * and is as accurate as ktime_get() is.
+ *
+ * This function returns -1 if NOHZ is not enabled.
+ */
+u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time)
+{
+	struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+	ktime_t now, iowait;
+
+	if (!tick_nohz_active)
+		return -1;
+
+	now = ktime_get();
+	if (last_update_time) {
+		update_ts_time_stats(cpu, ts, now, last_update_time);
+		iowait = ts->iowait_sleeptime;
+	} else {
+		if (ts->idle_active && nr_iowait_cpu(cpu) > 0) {
+			ktime_t delta = ktime_sub(now, ts->idle_entrytime);
+
+			iowait = ktime_add(ts->iowait_sleeptime, delta);
+		} else {
+			iowait = ts->iowait_sleeptime;
+		}
+	}
+
+	return ktime_to_us(iowait);
+}
+EXPORT_SYMBOL_GPL(get_cpu_iowait_time_us);
+
+static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
+{
+	hrtimer_cancel(&ts->sched_timer);
+	hrtimer_set_expires(&ts->sched_timer, ts->last_tick);
+
+	/* Forward the time to expire in the future */
+	hrtimer_forward(&ts->sched_timer, now, TICK_NSEC);
+
+	if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
+		hrtimer_start_expires(&ts->sched_timer,
+				      HRTIMER_MODE_ABS_PINNED_HARD);
+	} else {
+		tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1);
+	}
+
+	/*
+	 * Reset to make sure next tick stop doesn't get fooled by past
+	 * cached clock deadline.
+	 */
+	ts->next_tick = 0;
+}
+
+static inline bool local_timer_softirq_pending(void)
+{
+	return local_softirq_pending() & BIT(TIMER_SOFTIRQ);
+}
+
+static ktime_t tick_nohz_next_event(struct tick_sched *ts, int cpu)
+{
+	u64 basemono, next_tick, delta, expires;
+	unsigned long basejiff;
+	unsigned int seq;
+
+	/* Read jiffies and the time when jiffies were updated last */
+	do {
+		seq = read_seqcount_begin(&jiffies_seq);
+		basemono = last_jiffies_update;
+		basejiff = jiffies;
+	} while (read_seqcount_retry(&jiffies_seq, seq));
+	ts->last_jiffies = basejiff;
+	ts->timer_expires_base = basemono;
+
+	/*
+	 * Keep the periodic tick, when RCU, architecture or irq_work
+	 * requests it.
+	 * Aside of that check whether the local timer softirq is
+	 * pending. If so its a bad idea to call get_next_timer_interrupt()
+	 * because there is an already expired timer, so it will request
+	 * immediate expiry, which rearms the hardware timer with a
+	 * minimal delta which brings us back to this place
+	 * immediately. Lather, rinse and repeat...
+	 */
+	if (rcu_needs_cpu() || arch_needs_cpu() ||
+	    irq_work_needs_cpu() || local_timer_softirq_pending()) {
+		next_tick = basemono + TICK_NSEC;
+	} else {
+		/*
+		 * Get the next pending timer. If high resolution
+		 * timers are enabled this only takes the timer wheel
+		 * timers into account. If high resolution timers are
+		 * disabled this also looks at the next expiring
+		 * hrtimer.
+		 */
+		next_tick = get_next_timer_interrupt(basejiff, basemono);
+		ts->next_timer = next_tick;
+	}
+
+	/*
+	 * If the tick is due in the next period, keep it ticking or
+	 * force prod the timer.
+	 */
+	delta = next_tick - basemono;
+	if (delta <= (u64)TICK_NSEC) {
+		/*
+		 * Tell the timer code that the base is not idle, i.e. undo
+		 * the effect of get_next_timer_interrupt():
+		 */
+		timer_clear_idle();
+		/*
+		 * We've not stopped the tick yet, and there's a timer in the
+		 * next period, so no point in stopping it either, bail.
+		 */
+		if (!ts->tick_stopped) {
+			ts->timer_expires = 0;
+			goto out;
+		}
+	}
+
+	/*
+	 * If this CPU is the one which had the do_timer() duty last, we limit
+	 * the sleep time to the timekeeping max_deferment value.
+	 * Otherwise we can sleep as long as we want.
+	 */
+	delta = timekeeping_max_deferment();
+	if (cpu != tick_do_timer_cpu &&
+	    (tick_do_timer_cpu != TICK_DO_TIMER_NONE || !ts->do_timer_last))
+		delta = KTIME_MAX;
+
+	/* Calculate the next expiry time */
+	if (delta < (KTIME_MAX - basemono))
+		expires = basemono + delta;
+	else
+		expires = KTIME_MAX;
+
+	ts->timer_expires = min_t(u64, expires, next_tick);
+
+out:
+	return ts->timer_expires;
+}
+
+static void tick_nohz_stop_tick(struct tick_sched *ts, int cpu)
+{
+	struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
+	u64 basemono = ts->timer_expires_base;
+	u64 expires = ts->timer_expires;
+	ktime_t tick = expires;
+
+	/* Make sure we won't be trying to stop it twice in a row. */
+	ts->timer_expires_base = 0;
+
+	/*
+	 * If this CPU is the one which updates jiffies, then give up
+	 * the assignment and let it be taken by the CPU which runs
+	 * the tick timer next, which might be this CPU as well. If we
+	 * don't drop this here the jiffies might be stale and
+	 * do_timer() never invoked. Keep track of the fact that it
+	 * was the one which had the do_timer() duty last.
+	 */
+	if (cpu == tick_do_timer_cpu) {
+		tick_do_timer_cpu = TICK_DO_TIMER_NONE;
+		ts->do_timer_last = 1;
+	} else if (tick_do_timer_cpu != TICK_DO_TIMER_NONE) {
+		ts->do_timer_last = 0;
+	}
+
+	/* Skip reprogram of event if its not changed */
+	if (ts->tick_stopped && (expires == ts->next_tick)) {
+		/* Sanity check: make sure clockevent is actually programmed */
+		if (tick == KTIME_MAX || ts->next_tick == hrtimer_get_expires(&ts->sched_timer))
+			return;
+
+		WARN_ON_ONCE(1);
+		printk_once("basemono: %llu ts->next_tick: %llu dev->next_event: %llu timer->active: %d timer->expires: %llu\n",
+			    basemono, ts->next_tick, dev->next_event,
+			    hrtimer_active(&ts->sched_timer), hrtimer_get_expires(&ts->sched_timer));
+	}
+
+	/*
+	 * nohz_stop_sched_tick can be called several times before
+	 * the nohz_restart_sched_tick is called. This happens when
+	 * interrupts arrive which do not cause a reschedule. In the
+	 * first call we save the current tick time, so we can restart
+	 * the scheduler tick in nohz_restart_sched_tick.
+	 */
+	if (!ts->tick_stopped) {
+		calc_load_nohz_start();
+		quiet_vmstat();
+
+		ts->last_tick = hrtimer_get_expires(&ts->sched_timer);
+		ts->tick_stopped = 1;
+		trace_tick_stop(1, TICK_DEP_MASK_NONE);
+	}
+
+	ts->next_tick = tick;
+
+	/*
+	 * If the expiration time == KTIME_MAX, then we simply stop
+	 * the tick timer.
+	 */
+	if (unlikely(expires == KTIME_MAX)) {
+		if (ts->nohz_mode == NOHZ_MODE_HIGHRES)
+			hrtimer_cancel(&ts->sched_timer);
+		else
+			tick_program_event(KTIME_MAX, 1);
+		return;
+	}
+
+	if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
+		hrtimer_start(&ts->sched_timer, tick,
+			      HRTIMER_MODE_ABS_PINNED_HARD);
+	} else {
+		hrtimer_set_expires(&ts->sched_timer, tick);
+		tick_program_event(tick, 1);
+	}
+}
+
+static void tick_nohz_retain_tick(struct tick_sched *ts)
+{
+	ts->timer_expires_base = 0;
+}
+
+#ifdef CONFIG_NO_HZ_FULL
+static void tick_nohz_stop_sched_tick(struct tick_sched *ts, int cpu)
+{
+	if (tick_nohz_next_event(ts, cpu))
+		tick_nohz_stop_tick(ts, cpu);
+	else
+		tick_nohz_retain_tick(ts);
+}
+#endif /* CONFIG_NO_HZ_FULL */
+
+static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
+{
+	/* Update jiffies first */
+	tick_do_update_jiffies64(now);
+
+	/*
+	 * Clear the timer idle flag, so we avoid IPIs on remote queueing and
+	 * the clock forward checks in the enqueue path:
+	 */
+	timer_clear_idle();
+
+	calc_load_nohz_stop();
+	touch_softlockup_watchdog_sched();
+	/*
+	 * Cancel the scheduled timer and restore the tick
+	 */
+	ts->tick_stopped  = 0;
+	tick_nohz_restart(ts, now);
+}
+
+static void __tick_nohz_full_update_tick(struct tick_sched *ts,
+					 ktime_t now)
+{
+#ifdef CONFIG_NO_HZ_FULL
+	int cpu = smp_processor_id();
+
+	if (can_stop_full_tick(cpu, ts))
+		tick_nohz_stop_sched_tick(ts, cpu);
+	else if (ts->tick_stopped)
+		tick_nohz_restart_sched_tick(ts, now);
+#endif
+}
+
+static void tick_nohz_full_update_tick(struct tick_sched *ts)
+{
+	if (!tick_nohz_full_cpu(smp_processor_id()))
+		return;
+
+	if (!ts->tick_stopped && ts->nohz_mode == NOHZ_MODE_INACTIVE)
+		return;
+
+	__tick_nohz_full_update_tick(ts, ktime_get());
+}
+
+/*
+ * A pending softirq outside an IRQ (or softirq disabled section) context
+ * should be waiting for ksoftirqd to handle it. Therefore we shouldn't
+ * reach here due to the need_resched() early check in can_stop_idle_tick().
+ *
+ * However if we are between CPUHP_AP_SMPBOOT_THREADS and CPU_TEARDOWN_CPU on the
+ * cpu_down() process, softirqs can still be raised while ksoftirqd is parked,
+ * triggering the below since wakep_softirqd() is ignored.
+ *
+ */
+static bool report_idle_softirq(void)
+{
+	static int ratelimit;
+	unsigned int pending = local_softirq_pending();
+
+	if (likely(!pending))
+		return false;
+
+	/* Some softirqs claim to be safe against hotplug and ksoftirqd parking */
+	if (!cpu_active(smp_processor_id())) {
+		pending &= ~SOFTIRQ_HOTPLUG_SAFE_MASK;
+		if (!pending)
+			return false;
+	}
+
+	if (ratelimit >= 10)
+		return false;
+
+	/* On RT, softirqs handling may be waiting on some lock */
+	if (local_bh_blocked())
+		return false;
+
+	pr_warn("NOHZ tick-stop error: local softirq work is pending, handler #%02x!!!\n",
+		pending);
+	ratelimit++;
+
+	return true;
+}
+
+static bool can_stop_idle_tick(int cpu, struct tick_sched *ts)
+{
+	/*
+	 * If this CPU is offline and it is the one which updates
+	 * jiffies, then give up the assignment and let it be taken by
+	 * the CPU which runs the tick timer next. If we don't drop
+	 * this here the jiffies might be stale and do_timer() never
+	 * invoked.
+	 */
+	if (unlikely(!cpu_online(cpu))) {
+		if (cpu == tick_do_timer_cpu)
+			tick_do_timer_cpu = TICK_DO_TIMER_NONE;
+		/*
+		 * Make sure the CPU doesn't get fooled by obsolete tick
+		 * deadline if it comes back online later.
+		 */
+		ts->next_tick = 0;
+		return false;
+	}
+
+	if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE))
+		return false;
+
+	if (need_resched())
+		return false;
+
+	if (unlikely(report_idle_softirq()))
+		return false;
+
+	if (tick_nohz_full_enabled()) {
+		/*
+		 * Keep the tick alive to guarantee timekeeping progression
+		 * if there are full dynticks CPUs around
+		 */
+		if (tick_do_timer_cpu == cpu)
+			return false;
+
+		/* Should not happen for nohz-full */
+		if (WARN_ON_ONCE(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
+			return false;
+	}
+
+	return true;
+}
+
+static void __tick_nohz_idle_stop_tick(struct tick_sched *ts)
+{
+	ktime_t expires;
+	int cpu = smp_processor_id();
+
+	/*
+	 * If tick_nohz_get_sleep_length() ran tick_nohz_next_event(), the
+	 * tick timer expiration time is known already.
+	 */
+	if (ts->timer_expires_base)
+		expires = ts->timer_expires;
+	else if (can_stop_idle_tick(cpu, ts))
+		expires = tick_nohz_next_event(ts, cpu);
+	else
+		return;
+
+	ts->idle_calls++;
+
+	if (expires > 0LL) {
+		int was_stopped = ts->tick_stopped;
+
+		tick_nohz_stop_tick(ts, cpu);
+
+		ts->idle_sleeps++;
+		ts->idle_expires = expires;
+
+		if (!was_stopped && ts->tick_stopped) {
+			ts->idle_jiffies = ts->last_jiffies;
+			nohz_balance_enter_idle(cpu);
+		}
+	} else {
+		tick_nohz_retain_tick(ts);
+	}
+}
+
+/**
+ * tick_nohz_idle_stop_tick - stop the idle tick from the idle task
+ *
+ * When the next event is more than a tick into the future, stop the idle tick
+ */
+void tick_nohz_idle_stop_tick(void)
+{
+	__tick_nohz_idle_stop_tick(this_cpu_ptr(&tick_cpu_sched));
+}
+
+void tick_nohz_idle_retain_tick(void)
+{
+	tick_nohz_retain_tick(this_cpu_ptr(&tick_cpu_sched));
+	/*
+	 * Undo the effect of get_next_timer_interrupt() called from
+	 * tick_nohz_next_event().
+	 */
+	timer_clear_idle();
+}
+
+/**
+ * tick_nohz_idle_enter - prepare for entering idle on the current CPU
+ *
+ * Called when we start the idle loop.
+ */
+void tick_nohz_idle_enter(void)
+{
+	struct tick_sched *ts;
+
+	lockdep_assert_irqs_enabled();
+
+	local_irq_disable();
+
+	ts = this_cpu_ptr(&tick_cpu_sched);
+
+	WARN_ON_ONCE(ts->timer_expires_base);
+
+	ts->inidle = 1;
+	tick_nohz_start_idle(ts);
+
+	local_irq_enable();
+}
+
+/**
+ * tick_nohz_irq_exit - update next tick event from interrupt exit
+ *
+ * When an interrupt fires while we are idle and it doesn't cause
+ * a reschedule, it may still add, modify or delete a timer, enqueue
+ * an RCU callback, etc...
+ * So we need to re-calculate and reprogram the next tick event.
+ */
+void tick_nohz_irq_exit(void)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+
+	if (ts->inidle)
+		tick_nohz_start_idle(ts);
+	else
+		tick_nohz_full_update_tick(ts);
+}
+
+/**
+ * tick_nohz_idle_got_tick - Check whether or not the tick handler has run
+ */
+bool tick_nohz_idle_got_tick(void)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+
+	if (ts->got_idle_tick) {
+		ts->got_idle_tick = 0;
+		return true;
+	}
+	return false;
+}
+
+/**
+ * tick_nohz_get_next_hrtimer - return the next expiration time for the hrtimer
+ * or the tick, whatever that expires first. Note that, if the tick has been
+ * stopped, it returns the next hrtimer.
+ *
+ * Called from power state control code with interrupts disabled
+ */
+ktime_t tick_nohz_get_next_hrtimer(void)
+{
+	return __this_cpu_read(tick_cpu_device.evtdev)->next_event;
+}
+
+/**
+ * tick_nohz_get_sleep_length - return the expected length of the current sleep
+ * @delta_next: duration until the next event if the tick cannot be stopped
+ *
+ * Called from power state control code with interrupts disabled.
+ *
+ * The return value of this function and/or the value returned by it through the
+ * @delta_next pointer can be negative which must be taken into account by its
+ * callers.
+ */
+ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next)
+{
+	struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+	int cpu = smp_processor_id();
+	/*
+	 * The idle entry time is expected to be a sufficient approximation of
+	 * the current time at this point.
+	 */
+	ktime_t now = ts->idle_entrytime;
+	ktime_t next_event;
+
+	WARN_ON_ONCE(!ts->inidle);
+
+	*delta_next = ktime_sub(dev->next_event, now);
+
+	if (!can_stop_idle_tick(cpu, ts))
+		return *delta_next;
+
+	next_event = tick_nohz_next_event(ts, cpu);
+	if (!next_event)
+		return *delta_next;
+
+	/*
+	 * If the next highres timer to expire is earlier than next_event, the
+	 * idle governor needs to know that.
+	 */
+	next_event = min_t(u64, next_event,
+			   hrtimer_next_event_without(&ts->sched_timer));
+
+	return ktime_sub(next_event, now);
+}
+
+/**
+ * tick_nohz_get_idle_calls_cpu - return the current idle calls counter value
+ * for a particular CPU.
+ *
+ * Called from the schedutil frequency scaling governor in scheduler context.
+ */
+unsigned long tick_nohz_get_idle_calls_cpu(int cpu)
+{
+	struct tick_sched *ts = tick_get_tick_sched(cpu);
+
+	return ts->idle_calls;
+}
+
+/**
+ * tick_nohz_get_idle_calls - return the current idle calls counter value
+ *
+ * Called from the schedutil frequency scaling governor in scheduler context.
+ */
+unsigned long tick_nohz_get_idle_calls(void)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+
+	return ts->idle_calls;
+}
+
+static void tick_nohz_account_idle_time(struct tick_sched *ts,
+					ktime_t now)
+{
+	unsigned long ticks;
+
+	ts->idle_exittime = now;
+
+	if (vtime_accounting_enabled_this_cpu())
+		return;
+	/*
+	 * We stopped the tick in idle. Update process times would miss the
+	 * time we slept as update_process_times does only a 1 tick
+	 * accounting. Enforce that this is accounted to idle !
+	 */
+	ticks = jiffies - ts->idle_jiffies;
+	/*
+	 * We might be one off. Do not randomly account a huge number of ticks!
+	 */
+	if (ticks && ticks < LONG_MAX)
+		account_idle_ticks(ticks);
+}
+
+void tick_nohz_idle_restart_tick(void)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+
+	if (ts->tick_stopped) {
+		ktime_t now = ktime_get();
+		tick_nohz_restart_sched_tick(ts, now);
+		tick_nohz_account_idle_time(ts, now);
+	}
+}
+
+static void tick_nohz_idle_update_tick(struct tick_sched *ts, ktime_t now)
+{
+	if (tick_nohz_full_cpu(smp_processor_id()))
+		__tick_nohz_full_update_tick(ts, now);
+	else
+		tick_nohz_restart_sched_tick(ts, now);
+
+	tick_nohz_account_idle_time(ts, now);
+}
+
+/**
+ * tick_nohz_idle_exit - restart the idle tick from the idle task
+ *
+ * Restart the idle tick when the CPU is woken up from idle
+ * This also exit the RCU extended quiescent state. The CPU
+ * can use RCU again after this function is called.
+ */
+void tick_nohz_idle_exit(void)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+	bool idle_active, tick_stopped;
+	ktime_t now;
+
+	local_irq_disable();
+
+	WARN_ON_ONCE(!ts->inidle);
+	WARN_ON_ONCE(ts->timer_expires_base);
+
+	ts->inidle = 0;
+	idle_active = ts->idle_active;
+	tick_stopped = ts->tick_stopped;
+
+	if (idle_active || tick_stopped)
+		now = ktime_get();
+
+	if (idle_active)
+		tick_nohz_stop_idle(ts, now);
+
+	if (tick_stopped)
+		tick_nohz_idle_update_tick(ts, now);
+
+	local_irq_enable();
+}
+
+/*
+ * The nohz low res interrupt handler
+ */
+static void tick_nohz_handler(struct clock_event_device *dev)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+	struct pt_regs *regs = get_irq_regs();
+	ktime_t now = ktime_get();
+
+	dev->next_event = KTIME_MAX;
+
+	tick_sched_do_timer(ts, now);
+	tick_sched_handle(ts, regs);
+
+	if (unlikely(ts->tick_stopped)) {
+		/*
+		 * The clockevent device is not reprogrammed, so change the
+		 * clock event device to ONESHOT_STOPPED to avoid spurious
+		 * interrupts on devices which might not be truly one shot.
+		 */
+		tick_program_event(KTIME_MAX, 1);
+		return;
+	}
+
+	hrtimer_forward(&ts->sched_timer, now, TICK_NSEC);
+	tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1);
+}
+
+static inline void tick_nohz_activate(struct tick_sched *ts, int mode)
+{
+	if (!tick_nohz_enabled)
+		return;
+	ts->nohz_mode = mode;
+	/* One update is enough */
+	if (!test_and_set_bit(0, &tick_nohz_active))
+		timers_update_nohz();
+}
+
+/**
+ * tick_nohz_switch_to_nohz - switch to nohz mode
+ */
+static void tick_nohz_switch_to_nohz(void)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+	ktime_t next;
+
+	if (!tick_nohz_enabled)
+		return;
+
+	if (tick_switch_to_oneshot(tick_nohz_handler))
+		return;
+
+	/*
+	 * Recycle the hrtimer in ts, so we can share the
+	 * hrtimer_forward with the highres code.
+	 */
+	hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
+	/* Get the next period */
+	next = tick_init_jiffy_update();
+
+	hrtimer_set_expires(&ts->sched_timer, next);
+	hrtimer_forward_now(&ts->sched_timer, TICK_NSEC);
+	tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1);
+	tick_nohz_activate(ts, NOHZ_MODE_LOWRES);
+}
+
+static inline void tick_nohz_irq_enter(void)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+	ktime_t now;
+
+	if (!ts->idle_active && !ts->tick_stopped)
+		return;
+	now = ktime_get();
+	if (ts->idle_active)
+		tick_nohz_stop_idle(ts, now);
+	/*
+	 * If all CPUs are idle. We may need to update a stale jiffies value.
+	 * Note nohz_full is a special case: a timekeeper is guaranteed to stay
+	 * alive but it might be busy looping with interrupts disabled in some
+	 * rare case (typically stop machine). So we must make sure we have a
+	 * last resort.
+	 */
+	if (ts->tick_stopped)
+		tick_nohz_update_jiffies(now);
+}
+
+#else
+
+static inline void tick_nohz_switch_to_nohz(void) { }
+static inline void tick_nohz_irq_enter(void) { }
+static inline void tick_nohz_activate(struct tick_sched *ts, int mode) { }
+
+#endif /* CONFIG_NO_HZ_COMMON */
+
+/*
+ * Called from irq_enter to notify about the possible interruption of idle()
+ */
+void tick_irq_enter(void)
+{
+	tick_check_oneshot_broadcast_this_cpu();
+	tick_nohz_irq_enter();
+}
+
+/*
+ * High resolution timer specific code
+ */
+#ifdef CONFIG_HIGH_RES_TIMERS
+/*
+ * We rearm the timer until we get disabled by the idle code.
+ * Called with interrupts disabled.
+ */
+static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
+{
+	struct tick_sched *ts =
+		container_of(timer, struct tick_sched, sched_timer);
+	struct pt_regs *regs = get_irq_regs();
+	ktime_t now = ktime_get();
+
+	tick_sched_do_timer(ts, now);
+
+	/*
+	 * Do not call, when we are not in irq context and have
+	 * no valid regs pointer
+	 */
+	if (regs)
+		tick_sched_handle(ts, regs);
+	else
+		ts->next_tick = 0;
+
+	/* No need to reprogram if we are in idle or full dynticks mode */
+	if (unlikely(ts->tick_stopped))
+		return HRTIMER_NORESTART;
+
+	hrtimer_forward(timer, now, TICK_NSEC);
+
+	return HRTIMER_RESTART;
+}
+
+static int sched_skew_tick;
+
+static int __init skew_tick(char *str)
+{
+	get_option(&str, &sched_skew_tick);
+
+	return 0;
+}
+early_param("skew_tick", skew_tick);
+
+/**
+ * tick_setup_sched_timer - setup the tick emulation timer
+ */
+void tick_setup_sched_timer(void)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+	ktime_t now = ktime_get();
+
+	/*
+	 * Emulate tick processing via per-CPU hrtimers:
+	 */
+	hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
+	ts->sched_timer.function = tick_sched_timer;
+
+	/* Get the next period (per-CPU) */
+	hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update());
+
+	/* Offset the tick to avert jiffies_lock contention. */
+	if (sched_skew_tick) {
+		u64 offset = TICK_NSEC >> 1;
+		do_div(offset, num_possible_cpus());
+		offset *= smp_processor_id();
+		hrtimer_add_expires_ns(&ts->sched_timer, offset);
+	}
+
+	hrtimer_forward(&ts->sched_timer, now, TICK_NSEC);
+	hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED_HARD);
+	tick_nohz_activate(ts, NOHZ_MODE_HIGHRES);
+}
+#endif /* HIGH_RES_TIMERS */
+
+#if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
+void tick_cancel_sched_timer(int cpu)
+{
+	struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+	ktime_t idle_sleeptime, iowait_sleeptime;
+	unsigned long idle_calls, idle_sleeps;
+
+# ifdef CONFIG_HIGH_RES_TIMERS
+	if (ts->sched_timer.base)
+		hrtimer_cancel(&ts->sched_timer);
+# endif
+
+	idle_sleeptime = ts->idle_sleeptime;
+	iowait_sleeptime = ts->iowait_sleeptime;
+	idle_calls = ts->idle_calls;
+	idle_sleeps = ts->idle_sleeps;
+	memset(ts, 0, sizeof(*ts));
+	ts->idle_sleeptime = idle_sleeptime;
+	ts->iowait_sleeptime = iowait_sleeptime;
+	ts->idle_calls = idle_calls;
+	ts->idle_sleeps = idle_sleeps;
+}
+#endif
+
+/*
+ * Async notification about clocksource changes
+ */
+void tick_clock_notify(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		set_bit(0, &per_cpu(tick_cpu_sched, cpu).check_clocks);
+}
+
+/*
+ * Async notification about clock event changes
+ */
+void tick_oneshot_notify(void)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+
+	set_bit(0, &ts->check_clocks);
+}
+
+/*
+ * Check, if a change happened, which makes oneshot possible.
+ *
+ * Called cyclic from the hrtimer softirq (driven by the timer
+ * softirq) allow_nohz signals, that we can switch into low-res nohz
+ * mode, because high resolution timers are disabled (either compile
+ * or runtime). Called with interrupts disabled.
+ */
+int tick_check_oneshot_change(int allow_nohz)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+
+	if (!test_and_clear_bit(0, &ts->check_clocks))
+		return 0;
+
+	if (ts->nohz_mode != NOHZ_MODE_INACTIVE)
+		return 0;
+
+	if (!timekeeping_valid_for_hres() || !tick_is_oneshot_available())
+		return 0;
+
+	if (!allow_nohz)
+		return 1;
+
+	tick_nohz_switch_to_nohz();
+	return 0;
+}
diff --git a/kernel/time/tick-sched.h b/kernel/time/tick-sched.h
new file mode 100644
index 000000000..504649513
--- /dev/null
+++ b/kernel/time/tick-sched.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TICK_SCHED_H
+#define _TICK_SCHED_H
+
+#include <linux/hrtimer.h>
+
+enum tick_device_mode {
+	TICKDEV_MODE_PERIODIC,
+	TICKDEV_MODE_ONESHOT,
+};
+
+struct tick_device {
+	struct clock_event_device *evtdev;
+	enum tick_device_mode mode;
+};
+
+enum tick_nohz_mode {
+	NOHZ_MODE_INACTIVE,
+	NOHZ_MODE_LOWRES,
+	NOHZ_MODE_HIGHRES,
+};
+
+/**
+ * struct tick_sched - sched tick emulation and no idle tick control/stats
+ * @sched_timer:	hrtimer to schedule the periodic tick in high
+ *			resolution mode
+ * @check_clocks:	Notification mechanism about clocksource changes
+ * @nohz_mode:		Mode - one state of tick_nohz_mode
+ * @inidle:		Indicator that the CPU is in the tick idle mode
+ * @tick_stopped:	Indicator that the idle tick has been stopped
+ * @idle_active:	Indicator that the CPU is actively in the tick idle mode;
+ *			it is reset during irq handling phases.
+ * @do_timer_lst:	CPU was the last one doing do_timer before going idle
+ * @got_idle_tick:	Tick timer function has run with @inidle set
+ * @last_tick:		Store the last tick expiry time when the tick
+ *			timer is modified for nohz sleeps. This is necessary
+ *			to resume the tick timer operation in the timeline
+ *			when the CPU returns from nohz sleep.
+ * @next_tick:		Next tick to be fired when in dynticks mode.
+ * @idle_jiffies:	jiffies at the entry to idle for idle time accounting
+ * @idle_calls:		Total number of idle calls
+ * @idle_sleeps:	Number of idle calls, where the sched tick was stopped
+ * @idle_entrytime:	Time when the idle call was entered
+ * @idle_waketime:	Time when the idle was interrupted
+ * @idle_exittime:	Time when the idle state was left
+ * @idle_sleeptime:	Sum of the time slept in idle with sched tick stopped
+ * @iowait_sleeptime:	Sum of the time slept in idle with sched tick stopped, with IO outstanding
+ * @timer_expires:	Anticipated timer expiration time (in case sched tick is stopped)
+ * @timer_expires_base:	Base time clock monotonic for @timer_expires
+ * @next_timer:		Expiry time of next expiring timer for debugging purpose only
+ * @tick_dep_mask:	Tick dependency mask - is set, if someone needs the tick
+ * @last_tick_jiffies:	Value of jiffies seen on last tick
+ * @stalled_jiffies:	Number of stalled jiffies detected across ticks
+ */
+struct tick_sched {
+	struct hrtimer			sched_timer;
+	unsigned long			check_clocks;
+	enum tick_nohz_mode		nohz_mode;
+
+	unsigned int			inidle		: 1;
+	unsigned int			tick_stopped	: 1;
+	unsigned int			idle_active	: 1;
+	unsigned int			do_timer_last	: 1;
+	unsigned int			got_idle_tick	: 1;
+
+	ktime_t				last_tick;
+	ktime_t				next_tick;
+	unsigned long			idle_jiffies;
+	unsigned long			idle_calls;
+	unsigned long			idle_sleeps;
+	ktime_t				idle_entrytime;
+	ktime_t				idle_waketime;
+	ktime_t				idle_exittime;
+	ktime_t				idle_sleeptime;
+	ktime_t				iowait_sleeptime;
+	unsigned long			last_jiffies;
+	u64				timer_expires;
+	u64				timer_expires_base;
+	u64				next_timer;
+	ktime_t				idle_expires;
+	atomic_t			tick_dep_mask;
+	unsigned long			last_tick_jiffies;
+	unsigned int			stalled_jiffies;
+};
+
+extern struct tick_sched *tick_get_tick_sched(int cpu);
+
+extern void tick_setup_sched_timer(void);
+#if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
+extern void tick_cancel_sched_timer(int cpu);
+#else
+static inline void tick_cancel_sched_timer(int cpu) { }
+#endif
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+extern int __tick_broadcast_oneshot_control(enum tick_broadcast_state state);
+#else
+static inline int
+__tick_broadcast_oneshot_control(enum tick_broadcast_state state)
+{
+	return -EBUSY;
+}
+#endif
+
+#endif
diff --git a/kernel/time/time.c b/kernel/time/time.c
new file mode 100644
index 000000000..526257b37
--- /dev/null
+++ b/kernel/time/time.c
@@ -0,0 +1,909 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  This file contains the interface functions for the various time related
+ *  system calls: time, stime, gettimeofday, settimeofday, adjtime
+ *
+ * Modification history:
+ *
+ * 1993-09-02    Philip Gladstone
+ *      Created file with time related functions from sched/core.c and adjtimex()
+ * 1993-10-08    Torsten Duwe
+ *      adjtime interface update and CMOS clock write code
+ * 1995-08-13    Torsten Duwe
+ *      kernel PLL updated to 1994-12-13 specs (rfc-1589)
+ * 1999-01-16    Ulrich Windl
+ *	Introduced error checking for many cases in adjtimex().
+ *	Updated NTP code according to technical memorandum Jan '96
+ *	"A Kernel Model for Precision Timekeeping" by Dave Mills
+ *	Allow time_constant larger than MAXTC(6) for NTP v4 (MAXTC == 10)
+ *	(Even though the technical memorandum forbids it)
+ * 2004-07-14	 Christoph Lameter
+ *	Added getnstimeofday to allow the posix timer functions to return
+ *	with nanosecond accuracy
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/timex.h>
+#include <linux/capability.h>
+#include <linux/timekeeper_internal.h>
+#include <linux/errno.h>
+#include <linux/syscalls.h>
+#include <linux/security.h>
+#include <linux/fs.h>
+#include <linux/math64.h>
+#include <linux/ptrace.h>
+
+#include <linux/uaccess.h>
+#include <linux/compat.h>
+#include <asm/unistd.h>
+
+#include <generated/timeconst.h>
+#include "timekeeping.h"
+
+/*
+ * The timezone where the local system is located.  Used as a default by some
+ * programs who obtain this value by using gettimeofday.
+ */
+struct timezone sys_tz;
+
+EXPORT_SYMBOL(sys_tz);
+
+#ifdef __ARCH_WANT_SYS_TIME
+
+/*
+ * sys_time() can be implemented in user-level using
+ * sys_gettimeofday().  Is this for backwards compatibility?  If so,
+ * why not move it into the appropriate arch directory (for those
+ * architectures that need it).
+ */
+SYSCALL_DEFINE1(time, __kernel_old_time_t __user *, tloc)
+{
+	__kernel_old_time_t i = (__kernel_old_time_t)ktime_get_real_seconds();
+
+	if (tloc) {
+		if (put_user(i,tloc))
+			return -EFAULT;
+	}
+	force_successful_syscall_return();
+	return i;
+}
+
+/*
+ * sys_stime() can be implemented in user-level using
+ * sys_settimeofday().  Is this for backwards compatibility?  If so,
+ * why not move it into the appropriate arch directory (for those
+ * architectures that need it).
+ */
+
+SYSCALL_DEFINE1(stime, __kernel_old_time_t __user *, tptr)
+{
+	struct timespec64 tv;
+	int err;
+
+	if (get_user(tv.tv_sec, tptr))
+		return -EFAULT;
+
+	tv.tv_nsec = 0;
+
+	err = security_settime64(&tv, NULL);
+	if (err)
+		return err;
+
+	do_settimeofday64(&tv);
+	return 0;
+}
+
+#endif /* __ARCH_WANT_SYS_TIME */
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+#ifdef __ARCH_WANT_SYS_TIME32
+
+/* old_time32_t is a 32 bit "long" and needs to get converted. */
+SYSCALL_DEFINE1(time32, old_time32_t __user *, tloc)
+{
+	old_time32_t i;
+
+	i = (old_time32_t)ktime_get_real_seconds();
+
+	if (tloc) {
+		if (put_user(i,tloc))
+			return -EFAULT;
+	}
+	force_successful_syscall_return();
+	return i;
+}
+
+SYSCALL_DEFINE1(stime32, old_time32_t __user *, tptr)
+{
+	struct timespec64 tv;
+	int err;
+
+	if (get_user(tv.tv_sec, tptr))
+		return -EFAULT;
+
+	tv.tv_nsec = 0;
+
+	err = security_settime64(&tv, NULL);
+	if (err)
+		return err;
+
+	do_settimeofday64(&tv);
+	return 0;
+}
+
+#endif /* __ARCH_WANT_SYS_TIME32 */
+#endif
+
+SYSCALL_DEFINE2(gettimeofday, struct __kernel_old_timeval __user *, tv,
+		struct timezone __user *, tz)
+{
+	if (likely(tv != NULL)) {
+		struct timespec64 ts;
+
+		ktime_get_real_ts64(&ts);
+		if (put_user(ts.tv_sec, &tv->tv_sec) ||
+		    put_user(ts.tv_nsec / 1000, &tv->tv_usec))
+			return -EFAULT;
+	}
+	if (unlikely(tz != NULL)) {
+		if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
+			return -EFAULT;
+	}
+	return 0;
+}
+
+/*
+ * In case for some reason the CMOS clock has not already been running
+ * in UTC, but in some local time: The first time we set the timezone,
+ * we will warp the clock so that it is ticking UTC time instead of
+ * local time. Presumably, if someone is setting the timezone then we
+ * are running in an environment where the programs understand about
+ * timezones. This should be done at boot time in the /etc/rc script,
+ * as soon as possible, so that the clock can be set right. Otherwise,
+ * various programs will get confused when the clock gets warped.
+ */
+
+int do_sys_settimeofday64(const struct timespec64 *tv, const struct timezone *tz)
+{
+	static int firsttime = 1;
+	int error = 0;
+
+	if (tv && !timespec64_valid_settod(tv))
+		return -EINVAL;
+
+	error = security_settime64(tv, tz);
+	if (error)
+		return error;
+
+	if (tz) {
+		/* Verify we're within the +-15 hrs range */
+		if (tz->tz_minuteswest > 15*60 || tz->tz_minuteswest < -15*60)
+			return -EINVAL;
+
+		sys_tz = *tz;
+		update_vsyscall_tz();
+		if (firsttime) {
+			firsttime = 0;
+			if (!tv)
+				timekeeping_warp_clock();
+		}
+	}
+	if (tv)
+		return do_settimeofday64(tv);
+	return 0;
+}
+
+SYSCALL_DEFINE2(settimeofday, struct __kernel_old_timeval __user *, tv,
+		struct timezone __user *, tz)
+{
+	struct timespec64 new_ts;
+	struct timezone new_tz;
+
+	if (tv) {
+		if (get_user(new_ts.tv_sec, &tv->tv_sec) ||
+		    get_user(new_ts.tv_nsec, &tv->tv_usec))
+			return -EFAULT;
+
+		if (new_ts.tv_nsec > USEC_PER_SEC || new_ts.tv_nsec < 0)
+			return -EINVAL;
+
+		new_ts.tv_nsec *= NSEC_PER_USEC;
+	}
+	if (tz) {
+		if (copy_from_user(&new_tz, tz, sizeof(*tz)))
+			return -EFAULT;
+	}
+
+	return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(gettimeofday, struct old_timeval32 __user *, tv,
+		       struct timezone __user *, tz)
+{
+	if (tv) {
+		struct timespec64 ts;
+
+		ktime_get_real_ts64(&ts);
+		if (put_user(ts.tv_sec, &tv->tv_sec) ||
+		    put_user(ts.tv_nsec / 1000, &tv->tv_usec))
+			return -EFAULT;
+	}
+	if (tz) {
+		if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+COMPAT_SYSCALL_DEFINE2(settimeofday, struct old_timeval32 __user *, tv,
+		       struct timezone __user *, tz)
+{
+	struct timespec64 new_ts;
+	struct timezone new_tz;
+
+	if (tv) {
+		if (get_user(new_ts.tv_sec, &tv->tv_sec) ||
+		    get_user(new_ts.tv_nsec, &tv->tv_usec))
+			return -EFAULT;
+
+		if (new_ts.tv_nsec > USEC_PER_SEC || new_ts.tv_nsec < 0)
+			return -EINVAL;
+
+		new_ts.tv_nsec *= NSEC_PER_USEC;
+	}
+	if (tz) {
+		if (copy_from_user(&new_tz, tz, sizeof(*tz)))
+			return -EFAULT;
+	}
+
+	return do_sys_settimeofday64(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
+}
+#endif
+
+#ifdef CONFIG_64BIT
+SYSCALL_DEFINE1(adjtimex, struct __kernel_timex __user *, txc_p)
+{
+	struct __kernel_timex txc;		/* Local copy of parameter */
+	int ret;
+
+	/* Copy the user data space into the kernel copy
+	 * structure. But bear in mind that the structures
+	 * may change
+	 */
+	if (copy_from_user(&txc, txc_p, sizeof(struct __kernel_timex)))
+		return -EFAULT;
+	ret = do_adjtimex(&txc);
+	return copy_to_user(txc_p, &txc, sizeof(struct __kernel_timex)) ? -EFAULT : ret;
+}
+#endif
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+int get_old_timex32(struct __kernel_timex *txc, const struct old_timex32 __user *utp)
+{
+	struct old_timex32 tx32;
+
+	memset(txc, 0, sizeof(struct __kernel_timex));
+	if (copy_from_user(&tx32, utp, sizeof(struct old_timex32)))
+		return -EFAULT;
+
+	txc->modes = tx32.modes;
+	txc->offset = tx32.offset;
+	txc->freq = tx32.freq;
+	txc->maxerror = tx32.maxerror;
+	txc->esterror = tx32.esterror;
+	txc->status = tx32.status;
+	txc->constant = tx32.constant;
+	txc->precision = tx32.precision;
+	txc->tolerance = tx32.tolerance;
+	txc->time.tv_sec = tx32.time.tv_sec;
+	txc->time.tv_usec = tx32.time.tv_usec;
+	txc->tick = tx32.tick;
+	txc->ppsfreq = tx32.ppsfreq;
+	txc->jitter = tx32.jitter;
+	txc->shift = tx32.shift;
+	txc->stabil = tx32.stabil;
+	txc->jitcnt = tx32.jitcnt;
+	txc->calcnt = tx32.calcnt;
+	txc->errcnt = tx32.errcnt;
+	txc->stbcnt = tx32.stbcnt;
+
+	return 0;
+}
+
+int put_old_timex32(struct old_timex32 __user *utp, const struct __kernel_timex *txc)
+{
+	struct old_timex32 tx32;
+
+	memset(&tx32, 0, sizeof(struct old_timex32));
+	tx32.modes = txc->modes;
+	tx32.offset = txc->offset;
+	tx32.freq = txc->freq;
+	tx32.maxerror = txc->maxerror;
+	tx32.esterror = txc->esterror;
+	tx32.status = txc->status;
+	tx32.constant = txc->constant;
+	tx32.precision = txc->precision;
+	tx32.tolerance = txc->tolerance;
+	tx32.time.tv_sec = txc->time.tv_sec;
+	tx32.time.tv_usec = txc->time.tv_usec;
+	tx32.tick = txc->tick;
+	tx32.ppsfreq = txc->ppsfreq;
+	tx32.jitter = txc->jitter;
+	tx32.shift = txc->shift;
+	tx32.stabil = txc->stabil;
+	tx32.jitcnt = txc->jitcnt;
+	tx32.calcnt = txc->calcnt;
+	tx32.errcnt = txc->errcnt;
+	tx32.stbcnt = txc->stbcnt;
+	tx32.tai = txc->tai;
+	if (copy_to_user(utp, &tx32, sizeof(struct old_timex32)))
+		return -EFAULT;
+	return 0;
+}
+
+SYSCALL_DEFINE1(adjtimex_time32, struct old_timex32 __user *, utp)
+{
+	struct __kernel_timex txc;
+	int err, ret;
+
+	err = get_old_timex32(&txc, utp);
+	if (err)
+		return err;
+
+	ret = do_adjtimex(&txc);
+
+	err = put_old_timex32(utp, &txc);
+	if (err)
+		return err;
+
+	return ret;
+}
+#endif
+
+/*
+ * Convert jiffies to milliseconds and back.
+ *
+ * Avoid unnecessary multiplications/divisions in the
+ * two most common HZ cases:
+ */
+unsigned int jiffies_to_msecs(const unsigned long j)
+{
+#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
+	return (MSEC_PER_SEC / HZ) * j;
+#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
+	return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
+#else
+# if BITS_PER_LONG == 32
+	return (HZ_TO_MSEC_MUL32 * j + (1ULL << HZ_TO_MSEC_SHR32) - 1) >>
+	       HZ_TO_MSEC_SHR32;
+# else
+	return DIV_ROUND_UP(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN);
+# endif
+#endif
+}
+EXPORT_SYMBOL(jiffies_to_msecs);
+
+unsigned int jiffies_to_usecs(const unsigned long j)
+{
+	/*
+	 * Hz usually doesn't go much further MSEC_PER_SEC.
+	 * jiffies_to_usecs() and usecs_to_jiffies() depend on that.
+	 */
+	BUILD_BUG_ON(HZ > USEC_PER_SEC);
+
+#if !(USEC_PER_SEC % HZ)
+	return (USEC_PER_SEC / HZ) * j;
+#else
+# if BITS_PER_LONG == 32
+	return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;
+# else
+	return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN;
+# endif
+#endif
+}
+EXPORT_SYMBOL(jiffies_to_usecs);
+
+/*
+ * mktime64 - Converts date to seconds.
+ * Converts Gregorian date to seconds since 1970-01-01 00:00:00.
+ * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
+ * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
+ *
+ * [For the Julian calendar (which was used in Russia before 1917,
+ * Britain & colonies before 1752, anywhere else before 1582,
+ * and is still in use by some communities) leave out the
+ * -year/100+year/400 terms, and add 10.]
+ *
+ * This algorithm was first published by Gauss (I think).
+ *
+ * A leap second can be indicated by calling this function with sec as
+ * 60 (allowable under ISO 8601).  The leap second is treated the same
+ * as the following second since they don't exist in UNIX time.
+ *
+ * An encoding of midnight at the end of the day as 24:00:00 - ie. midnight
+ * tomorrow - (allowable under ISO 8601) is supported.
+ */
+time64_t mktime64(const unsigned int year0, const unsigned int mon0,
+		const unsigned int day, const unsigned int hour,
+		const unsigned int min, const unsigned int sec)
+{
+	unsigned int mon = mon0, year = year0;
+
+	/* 1..12 -> 11,12,1..10 */
+	if (0 >= (int) (mon -= 2)) {
+		mon += 12;	/* Puts Feb last since it has leap day */
+		year -= 1;
+	}
+
+	return ((((time64_t)
+		  (year/4 - year/100 + year/400 + 367*mon/12 + day) +
+		  year*365 - 719499
+	    )*24 + hour /* now have hours - midnight tomorrow handled here */
+	  )*60 + min /* now have minutes */
+	)*60 + sec; /* finally seconds */
+}
+EXPORT_SYMBOL(mktime64);
+
+struct __kernel_old_timeval ns_to_kernel_old_timeval(s64 nsec)
+{
+	struct timespec64 ts = ns_to_timespec64(nsec);
+	struct __kernel_old_timeval tv;
+
+	tv.tv_sec = ts.tv_sec;
+	tv.tv_usec = (suseconds_t)ts.tv_nsec / 1000;
+
+	return tv;
+}
+EXPORT_SYMBOL(ns_to_kernel_old_timeval);
+
+/**
+ * set_normalized_timespec - set timespec sec and nsec parts and normalize
+ *
+ * @ts:		pointer to timespec variable to be set
+ * @sec:	seconds to set
+ * @nsec:	nanoseconds to set
+ *
+ * Set seconds and nanoseconds field of a timespec variable and
+ * normalize to the timespec storage format
+ *
+ * Note: The tv_nsec part is always in the range of
+ *	0 <= tv_nsec < NSEC_PER_SEC
+ * For negative values only the tv_sec field is negative !
+ */
+void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec)
+{
+	while (nsec >= NSEC_PER_SEC) {
+		/*
+		 * The following asm() prevents the compiler from
+		 * optimising this loop into a modulo operation. See
+		 * also __iter_div_u64_rem() in include/linux/time.h
+		 */
+		asm("" : "+rm"(nsec));
+		nsec -= NSEC_PER_SEC;
+		++sec;
+	}
+	while (nsec < 0) {
+		asm("" : "+rm"(nsec));
+		nsec += NSEC_PER_SEC;
+		--sec;
+	}
+	ts->tv_sec = sec;
+	ts->tv_nsec = nsec;
+}
+EXPORT_SYMBOL(set_normalized_timespec64);
+
+/**
+ * ns_to_timespec64 - Convert nanoseconds to timespec64
+ * @nsec:       the nanoseconds value to be converted
+ *
+ * Returns the timespec64 representation of the nsec parameter.
+ */
+struct timespec64 ns_to_timespec64(s64 nsec)
+{
+	struct timespec64 ts = { 0, 0 };
+	s32 rem;
+
+	if (likely(nsec > 0)) {
+		ts.tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
+		ts.tv_nsec = rem;
+	} else if (nsec < 0) {
+		/*
+		 * With negative times, tv_sec points to the earlier
+		 * second, and tv_nsec counts the nanoseconds since
+		 * then, so tv_nsec is always a positive number.
+		 */
+		ts.tv_sec = -div_u64_rem(-nsec - 1, NSEC_PER_SEC, &rem) - 1;
+		ts.tv_nsec = NSEC_PER_SEC - rem - 1;
+	}
+
+	return ts;
+}
+EXPORT_SYMBOL(ns_to_timespec64);
+
+/**
+ * msecs_to_jiffies: - convert milliseconds to jiffies
+ * @m:	time in milliseconds
+ *
+ * conversion is done as follows:
+ *
+ * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)
+ *
+ * - 'too large' values [that would result in larger than
+ *   MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.
+ *
+ * - all other values are converted to jiffies by either multiplying
+ *   the input value by a factor or dividing it with a factor and
+ *   handling any 32-bit overflows.
+ *   for the details see __msecs_to_jiffies()
+ *
+ * msecs_to_jiffies() checks for the passed in value being a constant
+ * via __builtin_constant_p() allowing gcc to eliminate most of the
+ * code, __msecs_to_jiffies() is called if the value passed does not
+ * allow constant folding and the actual conversion must be done at
+ * runtime.
+ * the _msecs_to_jiffies helpers are the HZ dependent conversion
+ * routines found in include/linux/jiffies.h
+ */
+unsigned long __msecs_to_jiffies(const unsigned int m)
+{
+	/*
+	 * Negative value, means infinite timeout:
+	 */
+	if ((int)m < 0)
+		return MAX_JIFFY_OFFSET;
+	return _msecs_to_jiffies(m);
+}
+EXPORT_SYMBOL(__msecs_to_jiffies);
+
+unsigned long __usecs_to_jiffies(const unsigned int u)
+{
+	if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))
+		return MAX_JIFFY_OFFSET;
+	return _usecs_to_jiffies(u);
+}
+EXPORT_SYMBOL(__usecs_to_jiffies);
+
+/*
+ * The TICK_NSEC - 1 rounds up the value to the next resolution.  Note
+ * that a remainder subtract here would not do the right thing as the
+ * resolution values don't fall on second boundaries.  I.e. the line:
+ * nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding.
+ * Note that due to the small error in the multiplier here, this
+ * rounding is incorrect for sufficiently large values of tv_nsec, but
+ * well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're
+ * OK.
+ *
+ * Rather, we just shift the bits off the right.
+ *
+ * The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec
+ * value to a scaled second value.
+ */
+
+unsigned long
+timespec64_to_jiffies(const struct timespec64 *value)
+{
+	u64 sec = value->tv_sec;
+	long nsec = value->tv_nsec + TICK_NSEC - 1;
+
+	if (sec >= MAX_SEC_IN_JIFFIES){
+		sec = MAX_SEC_IN_JIFFIES;
+		nsec = 0;
+	}
+	return ((sec * SEC_CONVERSION) +
+		(((u64)nsec * NSEC_CONVERSION) >>
+		 (NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
+
+}
+EXPORT_SYMBOL(timespec64_to_jiffies);
+
+void
+jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value)
+{
+	/*
+	 * Convert jiffies to nanoseconds and separate with
+	 * one divide.
+	 */
+	u32 rem;
+	value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
+				    NSEC_PER_SEC, &rem);
+	value->tv_nsec = rem;
+}
+EXPORT_SYMBOL(jiffies_to_timespec64);
+
+/*
+ * Convert jiffies/jiffies_64 to clock_t and back.
+ */
+clock_t jiffies_to_clock_t(unsigned long x)
+{
+#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
+# if HZ < USER_HZ
+	return x * (USER_HZ / HZ);
+# else
+	return x / (HZ / USER_HZ);
+# endif
+#else
+	return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ);
+#endif
+}
+EXPORT_SYMBOL(jiffies_to_clock_t);
+
+unsigned long clock_t_to_jiffies(unsigned long x)
+{
+#if (HZ % USER_HZ)==0
+	if (x >= ~0UL / (HZ / USER_HZ))
+		return ~0UL;
+	return x * (HZ / USER_HZ);
+#else
+	/* Don't worry about loss of precision here .. */
+	if (x >= ~0UL / HZ * USER_HZ)
+		return ~0UL;
+
+	/* .. but do try to contain it here */
+	return div_u64((u64)x * HZ, USER_HZ);
+#endif
+}
+EXPORT_SYMBOL(clock_t_to_jiffies);
+
+u64 jiffies_64_to_clock_t(u64 x)
+{
+#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
+# if HZ < USER_HZ
+	x = div_u64(x * USER_HZ, HZ);
+# elif HZ > USER_HZ
+	x = div_u64(x, HZ / USER_HZ);
+# else
+	/* Nothing to do */
+# endif
+#else
+	/*
+	 * There are better ways that don't overflow early,
+	 * but even this doesn't overflow in hundreds of years
+	 * in 64 bits, so..
+	 */
+	x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ));
+#endif
+	return x;
+}
+EXPORT_SYMBOL(jiffies_64_to_clock_t);
+
+u64 nsec_to_clock_t(u64 x)
+{
+#if (NSEC_PER_SEC % USER_HZ) == 0
+	return div_u64(x, NSEC_PER_SEC / USER_HZ);
+#elif (USER_HZ % 512) == 0
+	return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512);
+#else
+	/*
+         * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024,
+         * overflow after 64.99 years.
+         * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
+         */
+	return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ);
+#endif
+}
+
+u64 jiffies64_to_nsecs(u64 j)
+{
+#if !(NSEC_PER_SEC % HZ)
+	return (NSEC_PER_SEC / HZ) * j;
+# else
+	return div_u64(j * HZ_TO_NSEC_NUM, HZ_TO_NSEC_DEN);
+#endif
+}
+EXPORT_SYMBOL(jiffies64_to_nsecs);
+
+u64 jiffies64_to_msecs(const u64 j)
+{
+#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
+	return (MSEC_PER_SEC / HZ) * j;
+#else
+	return div_u64(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN);
+#endif
+}
+EXPORT_SYMBOL(jiffies64_to_msecs);
+
+/**
+ * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64
+ *
+ * @n:	nsecs in u64
+ *
+ * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
+ * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
+ * for scheduler, not for use in device drivers to calculate timeout value.
+ *
+ * note:
+ *   NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
+ *   ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
+ */
+u64 nsecs_to_jiffies64(u64 n)
+{
+#if (NSEC_PER_SEC % HZ) == 0
+	/* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */
+	return div_u64(n, NSEC_PER_SEC / HZ);
+#elif (HZ % 512) == 0
+	/* overflow after 292 years if HZ = 1024 */
+	return div_u64(n * HZ / 512, NSEC_PER_SEC / 512);
+#else
+	/*
+	 * Generic case - optimized for cases where HZ is a multiple of 3.
+	 * overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc.
+	 */
+	return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ);
+#endif
+}
+EXPORT_SYMBOL(nsecs_to_jiffies64);
+
+/**
+ * nsecs_to_jiffies - Convert nsecs in u64 to jiffies
+ *
+ * @n:	nsecs in u64
+ *
+ * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
+ * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
+ * for scheduler, not for use in device drivers to calculate timeout value.
+ *
+ * note:
+ *   NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
+ *   ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
+ */
+unsigned long nsecs_to_jiffies(u64 n)
+{
+	return (unsigned long)nsecs_to_jiffies64(n);
+}
+EXPORT_SYMBOL_GPL(nsecs_to_jiffies);
+
+/*
+ * Add two timespec64 values and do a safety check for overflow.
+ * It's assumed that both values are valid (>= 0).
+ * And, each timespec64 is in normalized form.
+ */
+struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
+				const struct timespec64 rhs)
+{
+	struct timespec64 res;
+
+	set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec,
+			lhs.tv_nsec + rhs.tv_nsec);
+
+	if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) {
+		res.tv_sec = TIME64_MAX;
+		res.tv_nsec = 0;
+	}
+
+	return res;
+}
+
+int get_timespec64(struct timespec64 *ts,
+		   const struct __kernel_timespec __user *uts)
+{
+	struct __kernel_timespec kts;
+	int ret;
+
+	ret = copy_from_user(&kts, uts, sizeof(kts));
+	if (ret)
+		return -EFAULT;
+
+	ts->tv_sec = kts.tv_sec;
+
+	/* Zero out the padding in compat mode */
+	if (in_compat_syscall())
+		kts.tv_nsec &= 0xFFFFFFFFUL;
+
+	/* In 32-bit mode, this drops the padding */
+	ts->tv_nsec = kts.tv_nsec;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(get_timespec64);
+
+int put_timespec64(const struct timespec64 *ts,
+		   struct __kernel_timespec __user *uts)
+{
+	struct __kernel_timespec kts = {
+		.tv_sec = ts->tv_sec,
+		.tv_nsec = ts->tv_nsec
+	};
+
+	return copy_to_user(uts, &kts, sizeof(kts)) ? -EFAULT : 0;
+}
+EXPORT_SYMBOL_GPL(put_timespec64);
+
+static int __get_old_timespec32(struct timespec64 *ts64,
+				   const struct old_timespec32 __user *cts)
+{
+	struct old_timespec32 ts;
+	int ret;
+
+	ret = copy_from_user(&ts, cts, sizeof(ts));
+	if (ret)
+		return -EFAULT;
+
+	ts64->tv_sec = ts.tv_sec;
+	ts64->tv_nsec = ts.tv_nsec;
+
+	return 0;
+}
+
+static int __put_old_timespec32(const struct timespec64 *ts64,
+				   struct old_timespec32 __user *cts)
+{
+	struct old_timespec32 ts = {
+		.tv_sec = ts64->tv_sec,
+		.tv_nsec = ts64->tv_nsec
+	};
+	return copy_to_user(cts, &ts, sizeof(ts)) ? -EFAULT : 0;
+}
+
+int get_old_timespec32(struct timespec64 *ts, const void __user *uts)
+{
+	if (COMPAT_USE_64BIT_TIME)
+		return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
+	else
+		return __get_old_timespec32(ts, uts);
+}
+EXPORT_SYMBOL_GPL(get_old_timespec32);
+
+int put_old_timespec32(const struct timespec64 *ts, void __user *uts)
+{
+	if (COMPAT_USE_64BIT_TIME)
+		return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
+	else
+		return __put_old_timespec32(ts, uts);
+}
+EXPORT_SYMBOL_GPL(put_old_timespec32);
+
+int get_itimerspec64(struct itimerspec64 *it,
+			const struct __kernel_itimerspec __user *uit)
+{
+	int ret;
+
+	ret = get_timespec64(&it->it_interval, &uit->it_interval);
+	if (ret)
+		return ret;
+
+	ret = get_timespec64(&it->it_value, &uit->it_value);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(get_itimerspec64);
+
+int put_itimerspec64(const struct itimerspec64 *it,
+			struct __kernel_itimerspec __user *uit)
+{
+	int ret;
+
+	ret = put_timespec64(&it->it_interval, &uit->it_interval);
+	if (ret)
+		return ret;
+
+	ret = put_timespec64(&it->it_value, &uit->it_value);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(put_itimerspec64);
+
+int get_old_itimerspec32(struct itimerspec64 *its,
+			const struct old_itimerspec32 __user *uits)
+{
+
+	if (__get_old_timespec32(&its->it_interval, &uits->it_interval) ||
+	    __get_old_timespec32(&its->it_value, &uits->it_value))
+		return -EFAULT;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(get_old_itimerspec32);
+
+int put_old_itimerspec32(const struct itimerspec64 *its,
+			struct old_itimerspec32 __user *uits)
+{
+	if (__put_old_timespec32(&its->it_interval, &uits->it_interval) ||
+	    __put_old_timespec32(&its->it_value, &uits->it_value))
+		return -EFAULT;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(put_old_itimerspec32);
diff --git a/kernel/time/time_test.c b/kernel/time/time_test.c
new file mode 100644
index 000000000..831e8e779
--- /dev/null
+++ b/kernel/time/time_test.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: LGPL-2.1+
+
+#include <kunit/test.h>
+#include <linux/time.h>
+
+/*
+ * Traditional implementation of leap year evaluation.
+ */
+static bool is_leap(long year)
+{
+	return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
+}
+
+/*
+ * Gets the last day of a month.
+ */
+static int last_day_of_month(long year, int month)
+{
+	if (month == 2)
+		return 28 + is_leap(year);
+	if (month == 4 || month == 6 || month == 9 || month == 11)
+		return 30;
+	return 31;
+}
+
+/*
+ * Advances a date by one day.
+ */
+static void advance_date(long *year, int *month, int *mday, int *yday)
+{
+	if (*mday != last_day_of_month(*year, *month)) {
+		++*mday;
+		++*yday;
+		return;
+	}
+
+	*mday = 1;
+	if (*month != 12) {
+		++*month;
+		++*yday;
+		return;
+	}
+
+	*month = 1;
+	*yday  = 0;
+	++*year;
+}
+
+/*
+ * Checks every day in a 160000 years interval centered at 1970-01-01
+ * against the expected result.
+ */
+static void time64_to_tm_test_date_range(struct kunit *test)
+{
+	/*
+	 * 80000 years	= (80000 / 400) * 400 years
+	 *		= (80000 / 400) * 146097 days
+	 *		= (80000 / 400) * 146097 * 86400 seconds
+	 */
+	time64_t total_secs = ((time64_t) 80000) / 400 * 146097 * 86400;
+	long year = 1970 - 80000;
+	int month = 1;
+	int mdday = 1;
+	int yday = 0;
+
+	struct tm result;
+	time64_t secs;
+	s64 days;
+
+	for (secs = -total_secs; secs <= total_secs; secs += 86400) {
+
+		time64_to_tm(secs, 0, &result);
+
+		days = div_s64(secs, 86400);
+
+		#define FAIL_MSG "%05ld/%02d/%02d (%2d) : %ld", \
+			year, month, mdday, yday, days
+
+		KUNIT_ASSERT_EQ_MSG(test, year - 1900, result.tm_year, FAIL_MSG);
+		KUNIT_ASSERT_EQ_MSG(test, month - 1, result.tm_mon, FAIL_MSG);
+		KUNIT_ASSERT_EQ_MSG(test, mdday, result.tm_mday, FAIL_MSG);
+		KUNIT_ASSERT_EQ_MSG(test, yday, result.tm_yday, FAIL_MSG);
+
+		advance_date(&year, &month, &mdday, &yday);
+	}
+}
+
+static struct kunit_case time_test_cases[] = {
+	KUNIT_CASE(time64_to_tm_test_date_range),
+	{}
+};
+
+static struct kunit_suite time_test_suite = {
+	.name = "time_test_cases",
+	.test_cases = time_test_cases,
+};
+
+kunit_test_suite(time_test_suite);
+MODULE_LICENSE("GPL");
diff --git a/kernel/time/timeconst.bc b/kernel/time/timeconst.bc
new file mode 100644
index 000000000..7ed0e0fb5
--- /dev/null
+++ b/kernel/time/timeconst.bc
@@ -0,0 +1,117 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+scale=0
+
+define gcd(a,b) {
+	auto t;
+	while (b) {
+		t = b;
+		b = a % b;
+		a = t;
+	}
+	return a;
+}
+
+/* Division by reciprocal multiplication. */
+define fmul(b,n,d) {
+       return (2^b*n+d-1)/d;
+}
+
+/* Adjustment factor when a ceiling value is used.  Use as:
+   (imul * n) + (fmulxx * n + fadjxx) >> xx) */
+define fadj(b,n,d) {
+	auto v;
+	d = d/gcd(n,d);
+	v = 2^b*(d-1)/d;
+	return v;
+}
+
+/* Compute the appropriate mul/adj values as well as a shift count,
+   which brings the mul value into the range 2^b-1 <= x < 2^b.  Such
+   a shift value will be correct in the signed integer range and off
+   by at most one in the upper half of the unsigned range. */
+define fmuls(b,n,d) {
+	auto s, m;
+	for (s = 0; 1; s++) {
+		m = fmul(s,n,d);
+		if (m >= 2^(b-1))
+			return s;
+	}
+	return 0;
+}
+
+define timeconst(hz) {
+	print "/* Automatically generated by kernel/time/timeconst.bc */\n"
+	print "/* Time conversion constants for HZ == ", hz, " */\n"
+	print "\n"
+
+	print "#ifndef KERNEL_TIMECONST_H\n"
+	print "#define KERNEL_TIMECONST_H\n\n"
+
+	print "#include <linux/param.h>\n"
+	print "#include <linux/types.h>\n\n"
+
+	print "#if HZ != ", hz, "\n"
+	print "#error \qinclude/generated/timeconst.h has the wrong HZ value!\q\n"
+	print "#endif\n\n"
+
+	if (hz < 2) {
+		print "#error Totally bogus HZ value!\n"
+	} else {
+		s=fmuls(32,1000,hz)
+		obase=16
+		print "#define HZ_TO_MSEC_MUL32\tU64_C(0x", fmul(s,1000,hz), ")\n"
+		print "#define HZ_TO_MSEC_ADJ32\tU64_C(0x", fadj(s,1000,hz), ")\n"
+		obase=10
+		print "#define HZ_TO_MSEC_SHR32\t", s, "\n"
+
+		s=fmuls(32,hz,1000)
+		obase=16
+		print "#define MSEC_TO_HZ_MUL32\tU64_C(0x", fmul(s,hz,1000), ")\n"
+		print "#define MSEC_TO_HZ_ADJ32\tU64_C(0x", fadj(s,hz,1000), ")\n"
+		obase=10
+		print "#define MSEC_TO_HZ_SHR32\t", s, "\n"
+
+		obase=10
+		cd=gcd(hz,1000)
+		print "#define HZ_TO_MSEC_NUM\t\t", 1000/cd, "\n"
+		print "#define HZ_TO_MSEC_DEN\t\t", hz/cd, "\n"
+		print "#define MSEC_TO_HZ_NUM\t\t", hz/cd, "\n"
+		print "#define MSEC_TO_HZ_DEN\t\t", 1000/cd, "\n"
+		print "\n"
+
+		s=fmuls(32,1000000,hz)
+		obase=16
+		print "#define HZ_TO_USEC_MUL32\tU64_C(0x", fmul(s,1000000,hz), ")\n"
+		print "#define HZ_TO_USEC_ADJ32\tU64_C(0x", fadj(s,1000000,hz), ")\n"
+		obase=10
+		print "#define HZ_TO_USEC_SHR32\t", s, "\n"
+
+		s=fmuls(32,hz,1000000)
+		obase=16
+		print "#define USEC_TO_HZ_MUL32\tU64_C(0x", fmul(s,hz,1000000), ")\n"
+		print "#define USEC_TO_HZ_ADJ32\tU64_C(0x", fadj(s,hz,1000000), ")\n"
+		obase=10
+		print "#define USEC_TO_HZ_SHR32\t", s, "\n"
+
+		obase=10
+		cd=gcd(hz,1000000)
+		print "#define HZ_TO_USEC_NUM\t\t", 1000000/cd, "\n"
+		print "#define HZ_TO_USEC_DEN\t\t", hz/cd, "\n"
+		print "#define USEC_TO_HZ_NUM\t\t", hz/cd, "\n"
+		print "#define USEC_TO_HZ_DEN\t\t", 1000000/cd, "\n"
+
+		cd=gcd(hz,1000000000)
+		print "#define HZ_TO_NSEC_NUM\t\t", 1000000000/cd, "\n"
+		print "#define HZ_TO_NSEC_DEN\t\t", hz/cd, "\n"
+		print "#define NSEC_TO_HZ_NUM\t\t", hz/cd, "\n"
+		print "#define NSEC_TO_HZ_DEN\t\t", 1000000000/cd, "\n"
+		print "\n"
+
+		print "#endif /* KERNEL_TIMECONST_H */\n"
+	}
+	halt
+}
+
+hz = read();
+timeconst(hz)
diff --git a/kernel/time/timeconv.c b/kernel/time/timeconv.c
new file mode 100644
index 000000000..59b922c82
--- /dev/null
+++ b/kernel/time/timeconv.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: LGPL-2.0+
+/*
+ * Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
+ * This file is part of the GNU C Library.
+ * Contributed by Paul Eggert (eggert@twinsun.com).
+ *
+ * The GNU C Library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * The GNU C Library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with the GNU C Library; see the file COPYING.LIB.  If not,
+ * write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+/*
+ * Converts the calendar time to broken-down time representation
+ *
+ * 2009-7-14:
+ *   Moved from glibc-2.6 to kernel by Zhaolei<zhaolei@cn.fujitsu.com>
+ * 2021-06-02:
+ *   Reimplemented by Cassio Neri <cassio.neri@gmail.com>
+ */
+
+#include <linux/time.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+#define SECS_PER_HOUR	(60 * 60)
+#define SECS_PER_DAY	(SECS_PER_HOUR * 24)
+
+/**
+ * time64_to_tm - converts the calendar time to local broken-down time
+ *
+ * @totalsecs:	the number of seconds elapsed since 00:00:00 on January 1, 1970,
+ *		Coordinated Universal Time (UTC).
+ * @offset:	offset seconds adding to totalsecs.
+ * @result:	pointer to struct tm variable to receive broken-down time
+ */
+void time64_to_tm(time64_t totalsecs, int offset, struct tm *result)
+{
+	u32 u32tmp, day_of_century, year_of_century, day_of_year, month, day;
+	u64 u64tmp, udays, century, year;
+	bool is_Jan_or_Feb, is_leap_year;
+	long days, rem;
+	int remainder;
+
+	days = div_s64_rem(totalsecs, SECS_PER_DAY, &remainder);
+	rem = remainder;
+	rem += offset;
+	while (rem < 0) {
+		rem += SECS_PER_DAY;
+		--days;
+	}
+	while (rem >= SECS_PER_DAY) {
+		rem -= SECS_PER_DAY;
+		++days;
+	}
+
+	result->tm_hour = rem / SECS_PER_HOUR;
+	rem %= SECS_PER_HOUR;
+	result->tm_min = rem / 60;
+	result->tm_sec = rem % 60;
+
+	/* January 1, 1970 was a Thursday. */
+	result->tm_wday = (4 + days) % 7;
+	if (result->tm_wday < 0)
+		result->tm_wday += 7;
+
+	/*
+	 * The following algorithm is, basically, Proposition 6.3 of Neri
+	 * and Schneider [1]. In a few words: it works on the computational
+	 * (fictitious) calendar where the year starts in March, month = 2
+	 * (*), and finishes in February, month = 13. This calendar is
+	 * mathematically convenient because the day of the year does not
+	 * depend on whether the year is leap or not. For instance:
+	 *
+	 * March 1st		0-th day of the year;
+	 * ...
+	 * April 1st		31-st day of the year;
+	 * ...
+	 * January 1st		306-th day of the year; (Important!)
+	 * ...
+	 * February 28th	364-th day of the year;
+	 * February 29th	365-th day of the year (if it exists).
+	 *
+	 * After having worked out the date in the computational calendar
+	 * (using just arithmetics) it's easy to convert it to the
+	 * corresponding date in the Gregorian calendar.
+	 *
+	 * [1] "Euclidean Affine Functions and Applications to Calendar
+	 * Algorithms". https://arxiv.org/abs/2102.06959
+	 *
+	 * (*) The numbering of months follows tm more closely and thus,
+	 * is slightly different from [1].
+	 */
+
+	udays	= ((u64) days) + 2305843009213814918ULL;
+
+	u64tmp		= 4 * udays + 3;
+	century		= div64_u64_rem(u64tmp, 146097, &u64tmp);
+	day_of_century	= (u32) (u64tmp / 4);
+
+	u32tmp		= 4 * day_of_century + 3;
+	u64tmp		= 2939745ULL * u32tmp;
+	year_of_century	= upper_32_bits(u64tmp);
+	day_of_year	= lower_32_bits(u64tmp) / 2939745 / 4;
+
+	year		= 100 * century + year_of_century;
+	is_leap_year	= year_of_century ? !(year_of_century % 4) : !(century % 4);
+
+	u32tmp		= 2141 * day_of_year + 132377;
+	month		= u32tmp >> 16;
+	day		= ((u16) u32tmp) / 2141;
+
+	/*
+	 * Recall that January 1st is the 306-th day of the year in the
+	 * computational (not Gregorian) calendar.
+	 */
+	is_Jan_or_Feb	= day_of_year >= 306;
+
+	/* Convert to the Gregorian calendar and adjust to Unix time. */
+	year		= year + is_Jan_or_Feb - 6313183731940000ULL;
+	month		= is_Jan_or_Feb ? month - 12 : month;
+	day		= day + 1;
+	day_of_year	+= is_Jan_or_Feb ? -306 : 31 + 28 + is_leap_year;
+
+	/* Convert to tm's format. */
+	result->tm_year = (long) (year - 1900);
+	result->tm_mon  = (int) month;
+	result->tm_mday = (int) day;
+	result->tm_yday = (int) day_of_year;
+}
+EXPORT_SYMBOL(time64_to_tm);
diff --git a/kernel/time/timecounter.c b/kernel/time/timecounter.c
new file mode 100644
index 000000000..e6285288d
--- /dev/null
+++ b/kernel/time/timecounter.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Based on clocksource code. See commit 74d23cc704d1
+ */
+#include <linux/export.h>
+#include <linux/timecounter.h>
+
+void timecounter_init(struct timecounter *tc,
+		      const struct cyclecounter *cc,
+		      u64 start_tstamp)
+{
+	tc->cc = cc;
+	tc->cycle_last = cc->read(cc);
+	tc->nsec = start_tstamp;
+	tc->mask = (1ULL << cc->shift) - 1;
+	tc->frac = 0;
+}
+EXPORT_SYMBOL_GPL(timecounter_init);
+
+/**
+ * timecounter_read_delta - get nanoseconds since last call of this function
+ * @tc:         Pointer to time counter
+ *
+ * When the underlying cycle counter runs over, this will be handled
+ * correctly as long as it does not run over more than once between
+ * calls.
+ *
+ * The first call to this function for a new time counter initializes
+ * the time tracking and returns an undefined result.
+ */
+static u64 timecounter_read_delta(struct timecounter *tc)
+{
+	u64 cycle_now, cycle_delta;
+	u64 ns_offset;
+
+	/* read cycle counter: */
+	cycle_now = tc->cc->read(tc->cc);
+
+	/* calculate the delta since the last timecounter_read_delta(): */
+	cycle_delta = (cycle_now - tc->cycle_last) & tc->cc->mask;
+
+	/* convert to nanoseconds: */
+	ns_offset = cyclecounter_cyc2ns(tc->cc, cycle_delta,
+					tc->mask, &tc->frac);
+
+	/* update time stamp of timecounter_read_delta() call: */
+	tc->cycle_last = cycle_now;
+
+	return ns_offset;
+}
+
+u64 timecounter_read(struct timecounter *tc)
+{
+	u64 nsec;
+
+	/* increment time by nanoseconds since last call */
+	nsec = timecounter_read_delta(tc);
+	nsec += tc->nsec;
+	tc->nsec = nsec;
+
+	return nsec;
+}
+EXPORT_SYMBOL_GPL(timecounter_read);
+
+/*
+ * This is like cyclecounter_cyc2ns(), but it is used for computing a
+ * time previous to the time stored in the cycle counter.
+ */
+static u64 cc_cyc2ns_backwards(const struct cyclecounter *cc,
+			       u64 cycles, u64 mask, u64 frac)
+{
+	u64 ns = (u64) cycles;
+
+	ns = ((ns * cc->mult) - frac) >> cc->shift;
+
+	return ns;
+}
+
+u64 timecounter_cyc2time(const struct timecounter *tc,
+			 u64 cycle_tstamp)
+{
+	u64 delta = (cycle_tstamp - tc->cycle_last) & tc->cc->mask;
+	u64 nsec = tc->nsec, frac = tc->frac;
+
+	/*
+	 * Instead of always treating cycle_tstamp as more recent
+	 * than tc->cycle_last, detect when it is too far in the
+	 * future and treat it as old time stamp instead.
+	 */
+	if (delta > tc->cc->mask / 2) {
+		delta = (tc->cycle_last - cycle_tstamp) & tc->cc->mask;
+		nsec -= cc_cyc2ns_backwards(tc->cc, delta, tc->mask, frac);
+	} else {
+		nsec += cyclecounter_cyc2ns(tc->cc, delta, tc->mask, &frac);
+	}
+
+	return nsec;
+}
+EXPORT_SYMBOL_GPL(timecounter_cyc2time);
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
new file mode 100644
index 000000000..221c8c404
--- /dev/null
+++ b/kernel/time/timekeeping.c
@@ -0,0 +1,2503 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Kernel timekeeping code and accessor functions. Based on code from
+ *  timer.c, moved in commit 8524070b7982.
+ */
+#include <linux/timekeeper_internal.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/nmi.h>
+#include <linux/sched.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/clock.h>
+#include <linux/syscore_ops.h>
+#include <linux/clocksource.h>
+#include <linux/jiffies.h>
+#include <linux/time.h>
+#include <linux/timex.h>
+#include <linux/tick.h>
+#include <linux/stop_machine.h>
+#include <linux/pvclock_gtod.h>
+#include <linux/compiler.h>
+#include <linux/audit.h>
+#include <linux/random.h>
+
+#include "tick-internal.h"
+#include "ntp_internal.h"
+#include "timekeeping_internal.h"
+
+#define TK_CLEAR_NTP		(1 << 0)
+#define TK_MIRROR		(1 << 1)
+#define TK_CLOCK_WAS_SET	(1 << 2)
+
+enum timekeeping_adv_mode {
+	/* Update timekeeper when a tick has passed */
+	TK_ADV_TICK,
+
+	/* Update timekeeper on a direct frequency change */
+	TK_ADV_FREQ
+};
+
+DEFINE_RAW_SPINLOCK(timekeeper_lock);
+
+/*
+ * The most important data for readout fits into a single 64 byte
+ * cache line.
+ */
+static struct {
+	seqcount_raw_spinlock_t	seq;
+	struct timekeeper	timekeeper;
+} tk_core ____cacheline_aligned = {
+	.seq = SEQCNT_RAW_SPINLOCK_ZERO(tk_core.seq, &timekeeper_lock),
+};
+
+static struct timekeeper shadow_timekeeper;
+
+/* flag for if timekeeping is suspended */
+int __read_mostly timekeeping_suspended;
+
+/**
+ * struct tk_fast - NMI safe timekeeper
+ * @seq:	Sequence counter for protecting updates. The lowest bit
+ *		is the index for the tk_read_base array
+ * @base:	tk_read_base array. Access is indexed by the lowest bit of
+ *		@seq.
+ *
+ * See @update_fast_timekeeper() below.
+ */
+struct tk_fast {
+	seqcount_latch_t	seq;
+	struct tk_read_base	base[2];
+};
+
+/* Suspend-time cycles value for halted fast timekeeper. */
+static u64 cycles_at_suspend;
+
+static u64 dummy_clock_read(struct clocksource *cs)
+{
+	if (timekeeping_suspended)
+		return cycles_at_suspend;
+	return local_clock();
+}
+
+static struct clocksource dummy_clock = {
+	.read = dummy_clock_read,
+};
+
+/*
+ * Boot time initialization which allows local_clock() to be utilized
+ * during early boot when clocksources are not available. local_clock()
+ * returns nanoseconds already so no conversion is required, hence mult=1
+ * and shift=0. When the first proper clocksource is installed then
+ * the fast time keepers are updated with the correct values.
+ */
+#define FAST_TK_INIT						\
+	{							\
+		.clock		= &dummy_clock,			\
+		.mask		= CLOCKSOURCE_MASK(64),		\
+		.mult		= 1,				\
+		.shift		= 0,				\
+	}
+
+static struct tk_fast tk_fast_mono ____cacheline_aligned = {
+	.seq     = SEQCNT_LATCH_ZERO(tk_fast_mono.seq),
+	.base[0] = FAST_TK_INIT,
+	.base[1] = FAST_TK_INIT,
+};
+
+static struct tk_fast tk_fast_raw  ____cacheline_aligned = {
+	.seq     = SEQCNT_LATCH_ZERO(tk_fast_raw.seq),
+	.base[0] = FAST_TK_INIT,
+	.base[1] = FAST_TK_INIT,
+};
+
+static inline void tk_normalize_xtime(struct timekeeper *tk)
+{
+	while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
+		tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
+		tk->xtime_sec++;
+	}
+	while (tk->tkr_raw.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_raw.shift)) {
+		tk->tkr_raw.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
+		tk->raw_sec++;
+	}
+}
+
+static inline struct timespec64 tk_xtime(const struct timekeeper *tk)
+{
+	struct timespec64 ts;
+
+	ts.tv_sec = tk->xtime_sec;
+	ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
+	return ts;
+}
+
+static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
+{
+	tk->xtime_sec = ts->tv_sec;
+	tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
+}
+
+static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
+{
+	tk->xtime_sec += ts->tv_sec;
+	tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
+	tk_normalize_xtime(tk);
+}
+
+static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
+{
+	struct timespec64 tmp;
+
+	/*
+	 * Verify consistency of: offset_real = -wall_to_monotonic
+	 * before modifying anything
+	 */
+	set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
+					-tk->wall_to_monotonic.tv_nsec);
+	WARN_ON_ONCE(tk->offs_real != timespec64_to_ktime(tmp));
+	tk->wall_to_monotonic = wtm;
+	set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
+	tk->offs_real = timespec64_to_ktime(tmp);
+	tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
+}
+
+static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
+{
+	tk->offs_boot = ktime_add(tk->offs_boot, delta);
+	/*
+	 * Timespec representation for VDSO update to avoid 64bit division
+	 * on every update.
+	 */
+	tk->monotonic_to_boot = ktime_to_timespec64(tk->offs_boot);
+}
+
+/*
+ * tk_clock_read - atomic clocksource read() helper
+ *
+ * This helper is necessary to use in the read paths because, while the
+ * seqcount ensures we don't return a bad value while structures are updated,
+ * it doesn't protect from potential crashes. There is the possibility that
+ * the tkr's clocksource may change between the read reference, and the
+ * clock reference passed to the read function.  This can cause crashes if
+ * the wrong clocksource is passed to the wrong read function.
+ * This isn't necessary to use when holding the timekeeper_lock or doing
+ * a read of the fast-timekeeper tkrs (which is protected by its own locking
+ * and update logic).
+ */
+static inline u64 tk_clock_read(const struct tk_read_base *tkr)
+{
+	struct clocksource *clock = READ_ONCE(tkr->clock);
+
+	return clock->read(clock);
+}
+
+#ifdef CONFIG_DEBUG_TIMEKEEPING
+#define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
+
+static void timekeeping_check_update(struct timekeeper *tk, u64 offset)
+{
+
+	u64 max_cycles = tk->tkr_mono.clock->max_cycles;
+	const char *name = tk->tkr_mono.clock->name;
+
+	if (offset > max_cycles) {
+		printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
+				offset, name, max_cycles);
+		printk_deferred("         timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
+	} else {
+		if (offset > (max_cycles >> 1)) {
+			printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
+					offset, name, max_cycles >> 1);
+			printk_deferred("      timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
+		}
+	}
+
+	if (tk->underflow_seen) {
+		if (jiffies - tk->last_warning > WARNING_FREQ) {
+			printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
+			printk_deferred("         Please report this, consider using a different clocksource, if possible.\n");
+			printk_deferred("         Your kernel is probably still fine.\n");
+			tk->last_warning = jiffies;
+		}
+		tk->underflow_seen = 0;
+	}
+
+	if (tk->overflow_seen) {
+		if (jiffies - tk->last_warning > WARNING_FREQ) {
+			printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
+			printk_deferred("         Please report this, consider using a different clocksource, if possible.\n");
+			printk_deferred("         Your kernel is probably still fine.\n");
+			tk->last_warning = jiffies;
+		}
+		tk->overflow_seen = 0;
+	}
+}
+
+static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	u64 now, last, mask, max, delta;
+	unsigned int seq;
+
+	/*
+	 * Since we're called holding a seqcount, the data may shift
+	 * under us while we're doing the calculation. This can cause
+	 * false positives, since we'd note a problem but throw the
+	 * results away. So nest another seqcount here to atomically
+	 * grab the points we are checking with.
+	 */
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		now = tk_clock_read(tkr);
+		last = tkr->cycle_last;
+		mask = tkr->mask;
+		max = tkr->clock->max_cycles;
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	delta = clocksource_delta(now, last, mask);
+
+	/*
+	 * Try to catch underflows by checking if we are seeing small
+	 * mask-relative negative values.
+	 */
+	if (unlikely((~delta & mask) < (mask >> 3))) {
+		tk->underflow_seen = 1;
+		delta = 0;
+	}
+
+	/* Cap delta value to the max_cycles values to avoid mult overflows */
+	if (unlikely(delta > max)) {
+		tk->overflow_seen = 1;
+		delta = tkr->clock->max_cycles;
+	}
+
+	return delta;
+}
+#else
+static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset)
+{
+}
+static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr)
+{
+	u64 cycle_now, delta;
+
+	/* read clocksource */
+	cycle_now = tk_clock_read(tkr);
+
+	/* calculate the delta since the last update_wall_time */
+	delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
+
+	return delta;
+}
+#endif
+
+/**
+ * tk_setup_internals - Set up internals to use clocksource clock.
+ *
+ * @tk:		The target timekeeper to setup.
+ * @clock:		Pointer to clocksource.
+ *
+ * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
+ * pair and interval request.
+ *
+ * Unless you're the timekeeping code, you should not be using this!
+ */
+static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
+{
+	u64 interval;
+	u64 tmp, ntpinterval;
+	struct clocksource *old_clock;
+
+	++tk->cs_was_changed_seq;
+	old_clock = tk->tkr_mono.clock;
+	tk->tkr_mono.clock = clock;
+	tk->tkr_mono.mask = clock->mask;
+	tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono);
+
+	tk->tkr_raw.clock = clock;
+	tk->tkr_raw.mask = clock->mask;
+	tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
+
+	/* Do the ns -> cycle conversion first, using original mult */
+	tmp = NTP_INTERVAL_LENGTH;
+	tmp <<= clock->shift;
+	ntpinterval = tmp;
+	tmp += clock->mult/2;
+	do_div(tmp, clock->mult);
+	if (tmp == 0)
+		tmp = 1;
+
+	interval = (u64) tmp;
+	tk->cycle_interval = interval;
+
+	/* Go back from cycles -> shifted ns */
+	tk->xtime_interval = interval * clock->mult;
+	tk->xtime_remainder = ntpinterval - tk->xtime_interval;
+	tk->raw_interval = interval * clock->mult;
+
+	 /* if changing clocks, convert xtime_nsec shift units */
+	if (old_clock) {
+		int shift_change = clock->shift - old_clock->shift;
+		if (shift_change < 0) {
+			tk->tkr_mono.xtime_nsec >>= -shift_change;
+			tk->tkr_raw.xtime_nsec >>= -shift_change;
+		} else {
+			tk->tkr_mono.xtime_nsec <<= shift_change;
+			tk->tkr_raw.xtime_nsec <<= shift_change;
+		}
+	}
+
+	tk->tkr_mono.shift = clock->shift;
+	tk->tkr_raw.shift = clock->shift;
+
+	tk->ntp_error = 0;
+	tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
+	tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
+
+	/*
+	 * The timekeeper keeps its own mult values for the currently
+	 * active clocksource. These value will be adjusted via NTP
+	 * to counteract clock drifting.
+	 */
+	tk->tkr_mono.mult = clock->mult;
+	tk->tkr_raw.mult = clock->mult;
+	tk->ntp_err_mult = 0;
+	tk->skip_second_overflow = 0;
+}
+
+/* Timekeeper helper functions. */
+
+static inline u64 timekeeping_delta_to_ns(const struct tk_read_base *tkr, u64 delta)
+{
+	u64 nsec;
+
+	nsec = delta * tkr->mult + tkr->xtime_nsec;
+	nsec >>= tkr->shift;
+
+	return nsec;
+}
+
+static inline u64 timekeeping_get_ns(const struct tk_read_base *tkr)
+{
+	u64 delta;
+
+	delta = timekeeping_get_delta(tkr);
+	return timekeeping_delta_to_ns(tkr, delta);
+}
+
+static inline u64 timekeeping_cycles_to_ns(const struct tk_read_base *tkr, u64 cycles)
+{
+	u64 delta;
+
+	/* calculate the delta since the last update_wall_time */
+	delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
+	return timekeeping_delta_to_ns(tkr, delta);
+}
+
+/**
+ * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
+ * @tkr: Timekeeping readout base from which we take the update
+ * @tkf: Pointer to NMI safe timekeeper
+ *
+ * We want to use this from any context including NMI and tracing /
+ * instrumenting the timekeeping code itself.
+ *
+ * Employ the latch technique; see @raw_write_seqcount_latch.
+ *
+ * So if a NMI hits the update of base[0] then it will use base[1]
+ * which is still consistent. In the worst case this can result is a
+ * slightly wrong timestamp (a few nanoseconds). See
+ * @ktime_get_mono_fast_ns.
+ */
+static void update_fast_timekeeper(const struct tk_read_base *tkr,
+				   struct tk_fast *tkf)
+{
+	struct tk_read_base *base = tkf->base;
+
+	/* Force readers off to base[1] */
+	raw_write_seqcount_latch(&tkf->seq);
+
+	/* Update base[0] */
+	memcpy(base, tkr, sizeof(*base));
+
+	/* Force readers back to base[0] */
+	raw_write_seqcount_latch(&tkf->seq);
+
+	/* Update base[1] */
+	memcpy(base + 1, base, sizeof(*base));
+}
+
+static __always_inline u64 fast_tk_get_delta_ns(struct tk_read_base *tkr)
+{
+	u64 delta, cycles = tk_clock_read(tkr);
+
+	delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
+	return timekeeping_delta_to_ns(tkr, delta);
+}
+
+static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
+{
+	struct tk_read_base *tkr;
+	unsigned int seq;
+	u64 now;
+
+	do {
+		seq = raw_read_seqcount_latch(&tkf->seq);
+		tkr = tkf->base + (seq & 0x01);
+		now = ktime_to_ns(tkr->base);
+		now += fast_tk_get_delta_ns(tkr);
+	} while (read_seqcount_latch_retry(&tkf->seq, seq));
+
+	return now;
+}
+
+/**
+ * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
+ *
+ * This timestamp is not guaranteed to be monotonic across an update.
+ * The timestamp is calculated by:
+ *
+ *	now = base_mono + clock_delta * slope
+ *
+ * So if the update lowers the slope, readers who are forced to the
+ * not yet updated second array are still using the old steeper slope.
+ *
+ * tmono
+ * ^
+ * |    o  n
+ * |   o n
+ * |  u
+ * | o
+ * |o
+ * |12345678---> reader order
+ *
+ * o = old slope
+ * u = update
+ * n = new slope
+ *
+ * So reader 6 will observe time going backwards versus reader 5.
+ *
+ * While other CPUs are likely to be able to observe that, the only way
+ * for a CPU local observation is when an NMI hits in the middle of
+ * the update. Timestamps taken from that NMI context might be ahead
+ * of the following timestamps. Callers need to be aware of that and
+ * deal with it.
+ */
+u64 notrace ktime_get_mono_fast_ns(void)
+{
+	return __ktime_get_fast_ns(&tk_fast_mono);
+}
+EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
+
+/**
+ * ktime_get_raw_fast_ns - Fast NMI safe access to clock monotonic raw
+ *
+ * Contrary to ktime_get_mono_fast_ns() this is always correct because the
+ * conversion factor is not affected by NTP/PTP correction.
+ */
+u64 notrace ktime_get_raw_fast_ns(void)
+{
+	return __ktime_get_fast_ns(&tk_fast_raw);
+}
+EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
+
+/**
+ * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock.
+ *
+ * To keep it NMI safe since we're accessing from tracing, we're not using a
+ * separate timekeeper with updates to monotonic clock and boot offset
+ * protected with seqcounts. This has the following minor side effects:
+ *
+ * (1) Its possible that a timestamp be taken after the boot offset is updated
+ * but before the timekeeper is updated. If this happens, the new boot offset
+ * is added to the old timekeeping making the clock appear to update slightly
+ * earlier:
+ *    CPU 0                                        CPU 1
+ *    timekeeping_inject_sleeptime64()
+ *    __timekeeping_inject_sleeptime(tk, delta);
+ *                                                 timestamp();
+ *    timekeeping_update(tk, TK_CLEAR_NTP...);
+ *
+ * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be
+ * partially updated.  Since the tk->offs_boot update is a rare event, this
+ * should be a rare occurrence which postprocessing should be able to handle.
+ *
+ * The caveats vs. timestamp ordering as documented for ktime_get_mono_fast_ns()
+ * apply as well.
+ */
+u64 notrace ktime_get_boot_fast_ns(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+
+	return (ktime_get_mono_fast_ns() + ktime_to_ns(data_race(tk->offs_boot)));
+}
+EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);
+
+/**
+ * ktime_get_tai_fast_ns - NMI safe and fast access to tai clock.
+ *
+ * The same limitations as described for ktime_get_boot_fast_ns() apply. The
+ * mono time and the TAI offset are not read atomically which may yield wrong
+ * readouts. However, an update of the TAI offset is an rare event e.g., caused
+ * by settime or adjtimex with an offset. The user of this function has to deal
+ * with the possibility of wrong timestamps in post processing.
+ */
+u64 notrace ktime_get_tai_fast_ns(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+
+	return (ktime_get_mono_fast_ns() + ktime_to_ns(data_race(tk->offs_tai)));
+}
+EXPORT_SYMBOL_GPL(ktime_get_tai_fast_ns);
+
+static __always_inline u64 __ktime_get_real_fast(struct tk_fast *tkf, u64 *mono)
+{
+	struct tk_read_base *tkr;
+	u64 basem, baser, delta;
+	unsigned int seq;
+
+	do {
+		seq = raw_read_seqcount_latch(&tkf->seq);
+		tkr = tkf->base + (seq & 0x01);
+		basem = ktime_to_ns(tkr->base);
+		baser = ktime_to_ns(tkr->base_real);
+		delta = fast_tk_get_delta_ns(tkr);
+	} while (read_seqcount_latch_retry(&tkf->seq, seq));
+
+	if (mono)
+		*mono = basem + delta;
+	return baser + delta;
+}
+
+/**
+ * ktime_get_real_fast_ns: - NMI safe and fast access to clock realtime.
+ *
+ * See ktime_get_mono_fast_ns() for documentation of the time stamp ordering.
+ */
+u64 ktime_get_real_fast_ns(void)
+{
+	return __ktime_get_real_fast(&tk_fast_mono, NULL);
+}
+EXPORT_SYMBOL_GPL(ktime_get_real_fast_ns);
+
+/**
+ * ktime_get_fast_timestamps: - NMI safe timestamps
+ * @snapshot:	Pointer to timestamp storage
+ *
+ * Stores clock monotonic, boottime and realtime timestamps.
+ *
+ * Boot time is a racy access on 32bit systems if the sleep time injection
+ * happens late during resume and not in timekeeping_resume(). That could
+ * be avoided by expanding struct tk_read_base with boot offset for 32bit
+ * and adding more overhead to the update. As this is a hard to observe
+ * once per resume event which can be filtered with reasonable effort using
+ * the accurate mono/real timestamps, it's probably not worth the trouble.
+ *
+ * Aside of that it might be possible on 32 and 64 bit to observe the
+ * following when the sleep time injection happens late:
+ *
+ * CPU 0				CPU 1
+ * timekeeping_resume()
+ * ktime_get_fast_timestamps()
+ *	mono, real = __ktime_get_real_fast()
+ *					inject_sleep_time()
+ *					   update boot offset
+ *	boot = mono + bootoffset;
+ *
+ * That means that boot time already has the sleep time adjustment, but
+ * real time does not. On the next readout both are in sync again.
+ *
+ * Preventing this for 64bit is not really feasible without destroying the
+ * careful cache layout of the timekeeper because the sequence count and
+ * struct tk_read_base would then need two cache lines instead of one.
+ *
+ * Access to the time keeper clock source is disabled across the innermost
+ * steps of suspend/resume. The accessors still work, but the timestamps
+ * are frozen until time keeping is resumed which happens very early.
+ *
+ * For regular suspend/resume there is no observable difference vs. sched
+ * clock, but it might affect some of the nasty low level debug printks.
+ *
+ * OTOH, access to sched clock is not guaranteed across suspend/resume on
+ * all systems either so it depends on the hardware in use.
+ *
+ * If that turns out to be a real problem then this could be mitigated by
+ * using sched clock in a similar way as during early boot. But it's not as
+ * trivial as on early boot because it needs some careful protection
+ * against the clock monotonic timestamp jumping backwards on resume.
+ */
+void ktime_get_fast_timestamps(struct ktime_timestamps *snapshot)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+
+	snapshot->real = __ktime_get_real_fast(&tk_fast_mono, &snapshot->mono);
+	snapshot->boot = snapshot->mono + ktime_to_ns(data_race(tk->offs_boot));
+}
+
+/**
+ * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
+ * @tk: Timekeeper to snapshot.
+ *
+ * It generally is unsafe to access the clocksource after timekeeping has been
+ * suspended, so take a snapshot of the readout base of @tk and use it as the
+ * fast timekeeper's readout base while suspended.  It will return the same
+ * number of cycles every time until timekeeping is resumed at which time the
+ * proper readout base for the fast timekeeper will be restored automatically.
+ */
+static void halt_fast_timekeeper(const struct timekeeper *tk)
+{
+	static struct tk_read_base tkr_dummy;
+	const struct tk_read_base *tkr = &tk->tkr_mono;
+
+	memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
+	cycles_at_suspend = tk_clock_read(tkr);
+	tkr_dummy.clock = &dummy_clock;
+	tkr_dummy.base_real = tkr->base + tk->offs_real;
+	update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
+
+	tkr = &tk->tkr_raw;
+	memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
+	tkr_dummy.clock = &dummy_clock;
+	update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
+}
+
+static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
+
+static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
+{
+	raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
+}
+
+/**
+ * pvclock_gtod_register_notifier - register a pvclock timedata update listener
+ * @nb: Pointer to the notifier block to register
+ */
+int pvclock_gtod_register_notifier(struct notifier_block *nb)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned long flags;
+	int ret;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
+	update_pvclock_gtod(tk, true);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
+
+/**
+ * pvclock_gtod_unregister_notifier - unregister a pvclock
+ * timedata update listener
+ * @nb: Pointer to the notifier block to unregister
+ */
+int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
+{
+	unsigned long flags;
+	int ret;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
+
+/*
+ * tk_update_leap_state - helper to update the next_leap_ktime
+ */
+static inline void tk_update_leap_state(struct timekeeper *tk)
+{
+	tk->next_leap_ktime = ntp_get_next_leap();
+	if (tk->next_leap_ktime != KTIME_MAX)
+		/* Convert to monotonic time */
+		tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real);
+}
+
+/*
+ * Update the ktime_t based scalar nsec members of the timekeeper
+ */
+static inline void tk_update_ktime_data(struct timekeeper *tk)
+{
+	u64 seconds;
+	u32 nsec;
+
+	/*
+	 * The xtime based monotonic readout is:
+	 *	nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
+	 * The ktime based monotonic readout is:
+	 *	nsec = base_mono + now();
+	 * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
+	 */
+	seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
+	nsec = (u32) tk->wall_to_monotonic.tv_nsec;
+	tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
+
+	/*
+	 * The sum of the nanoseconds portions of xtime and
+	 * wall_to_monotonic can be greater/equal one second. Take
+	 * this into account before updating tk->ktime_sec.
+	 */
+	nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
+	if (nsec >= NSEC_PER_SEC)
+		seconds++;
+	tk->ktime_sec = seconds;
+
+	/* Update the monotonic raw base */
+	tk->tkr_raw.base = ns_to_ktime(tk->raw_sec * NSEC_PER_SEC);
+}
+
+/* must hold timekeeper_lock */
+static void timekeeping_update(struct timekeeper *tk, unsigned int action)
+{
+	if (action & TK_CLEAR_NTP) {
+		tk->ntp_error = 0;
+		ntp_clear();
+	}
+
+	tk_update_leap_state(tk);
+	tk_update_ktime_data(tk);
+
+	update_vsyscall(tk);
+	update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
+
+	tk->tkr_mono.base_real = tk->tkr_mono.base + tk->offs_real;
+	update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
+	update_fast_timekeeper(&tk->tkr_raw,  &tk_fast_raw);
+
+	if (action & TK_CLOCK_WAS_SET)
+		tk->clock_was_set_seq++;
+	/*
+	 * The mirroring of the data to the shadow-timekeeper needs
+	 * to happen last here to ensure we don't over-write the
+	 * timekeeper structure on the next update with stale data
+	 */
+	if (action & TK_MIRROR)
+		memcpy(&shadow_timekeeper, &tk_core.timekeeper,
+		       sizeof(tk_core.timekeeper));
+}
+
+/**
+ * timekeeping_forward_now - update clock to the current time
+ * @tk:		Pointer to the timekeeper to update
+ *
+ * Forward the current clock to update its state since the last call to
+ * update_wall_time(). This is useful before significant clock changes,
+ * as it avoids having to deal with this time offset explicitly.
+ */
+static void timekeeping_forward_now(struct timekeeper *tk)
+{
+	u64 cycle_now, delta;
+
+	cycle_now = tk_clock_read(&tk->tkr_mono);
+	delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
+	tk->tkr_mono.cycle_last = cycle_now;
+	tk->tkr_raw.cycle_last  = cycle_now;
+
+	tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
+	tk->tkr_raw.xtime_nsec += delta * tk->tkr_raw.mult;
+
+	tk_normalize_xtime(tk);
+}
+
+/**
+ * ktime_get_real_ts64 - Returns the time of day in a timespec64.
+ * @ts:		pointer to the timespec to be set
+ *
+ * Returns the time of day in a timespec64 (WARN if suspended).
+ */
+void ktime_get_real_ts64(struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	u64 nsecs;
+
+	WARN_ON(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		ts->tv_sec = tk->xtime_sec;
+		nsecs = timekeeping_get_ns(&tk->tkr_mono);
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	ts->tv_nsec = 0;
+	timespec64_add_ns(ts, nsecs);
+}
+EXPORT_SYMBOL(ktime_get_real_ts64);
+
+ktime_t ktime_get(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	ktime_t base;
+	u64 nsecs;
+
+	WARN_ON(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		base = tk->tkr_mono.base;
+		nsecs = timekeeping_get_ns(&tk->tkr_mono);
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ktime_add_ns(base, nsecs);
+}
+EXPORT_SYMBOL_GPL(ktime_get);
+
+u32 ktime_get_resolution_ns(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	u32 nsecs;
+
+	WARN_ON(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return nsecs;
+}
+EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
+
+static ktime_t *offsets[TK_OFFS_MAX] = {
+	[TK_OFFS_REAL]	= &tk_core.timekeeper.offs_real,
+	[TK_OFFS_BOOT]	= &tk_core.timekeeper.offs_boot,
+	[TK_OFFS_TAI]	= &tk_core.timekeeper.offs_tai,
+};
+
+ktime_t ktime_get_with_offset(enum tk_offsets offs)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	ktime_t base, *offset = offsets[offs];
+	u64 nsecs;
+
+	WARN_ON(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		base = ktime_add(tk->tkr_mono.base, *offset);
+		nsecs = timekeeping_get_ns(&tk->tkr_mono);
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ktime_add_ns(base, nsecs);
+
+}
+EXPORT_SYMBOL_GPL(ktime_get_with_offset);
+
+ktime_t ktime_get_coarse_with_offset(enum tk_offsets offs)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	ktime_t base, *offset = offsets[offs];
+	u64 nsecs;
+
+	WARN_ON(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		base = ktime_add(tk->tkr_mono.base, *offset);
+		nsecs = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ktime_add_ns(base, nsecs);
+}
+EXPORT_SYMBOL_GPL(ktime_get_coarse_with_offset);
+
+/**
+ * ktime_mono_to_any() - convert monotonic time to any other time
+ * @tmono:	time to convert.
+ * @offs:	which offset to use
+ */
+ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
+{
+	ktime_t *offset = offsets[offs];
+	unsigned int seq;
+	ktime_t tconv;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		tconv = ktime_add(tmono, *offset);
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return tconv;
+}
+EXPORT_SYMBOL_GPL(ktime_mono_to_any);
+
+/**
+ * ktime_get_raw - Returns the raw monotonic time in ktime_t format
+ */
+ktime_t ktime_get_raw(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	ktime_t base;
+	u64 nsecs;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		base = tk->tkr_raw.base;
+		nsecs = timekeeping_get_ns(&tk->tkr_raw);
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ktime_add_ns(base, nsecs);
+}
+EXPORT_SYMBOL_GPL(ktime_get_raw);
+
+/**
+ * ktime_get_ts64 - get the monotonic clock in timespec64 format
+ * @ts:		pointer to timespec variable
+ *
+ * The function calculates the monotonic clock from the realtime
+ * clock and the wall_to_monotonic offset and stores the result
+ * in normalized timespec64 format in the variable pointed to by @ts.
+ */
+void ktime_get_ts64(struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct timespec64 tomono;
+	unsigned int seq;
+	u64 nsec;
+
+	WARN_ON(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		ts->tv_sec = tk->xtime_sec;
+		nsec = timekeeping_get_ns(&tk->tkr_mono);
+		tomono = tk->wall_to_monotonic;
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	ts->tv_sec += tomono.tv_sec;
+	ts->tv_nsec = 0;
+	timespec64_add_ns(ts, nsec + tomono.tv_nsec);
+}
+EXPORT_SYMBOL_GPL(ktime_get_ts64);
+
+/**
+ * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
+ *
+ * Returns the seconds portion of CLOCK_MONOTONIC with a single non
+ * serialized read. tk->ktime_sec is of type 'unsigned long' so this
+ * works on both 32 and 64 bit systems. On 32 bit systems the readout
+ * covers ~136 years of uptime which should be enough to prevent
+ * premature wrap arounds.
+ */
+time64_t ktime_get_seconds(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+
+	WARN_ON(timekeeping_suspended);
+	return tk->ktime_sec;
+}
+EXPORT_SYMBOL_GPL(ktime_get_seconds);
+
+/**
+ * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
+ *
+ * Returns the wall clock seconds since 1970.
+ *
+ * For 64bit systems the fast access to tk->xtime_sec is preserved. On
+ * 32bit systems the access must be protected with the sequence
+ * counter to provide "atomic" access to the 64bit tk->xtime_sec
+ * value.
+ */
+time64_t ktime_get_real_seconds(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	time64_t seconds;
+	unsigned int seq;
+
+	if (IS_ENABLED(CONFIG_64BIT))
+		return tk->xtime_sec;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		seconds = tk->xtime_sec;
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return seconds;
+}
+EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
+
+/**
+ * __ktime_get_real_seconds - The same as ktime_get_real_seconds
+ * but without the sequence counter protect. This internal function
+ * is called just when timekeeping lock is already held.
+ */
+noinstr time64_t __ktime_get_real_seconds(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+
+	return tk->xtime_sec;
+}
+
+/**
+ * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
+ * @systime_snapshot:	pointer to struct receiving the system time snapshot
+ */
+void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	ktime_t base_raw;
+	ktime_t base_real;
+	u64 nsec_raw;
+	u64 nsec_real;
+	u64 now;
+
+	WARN_ON_ONCE(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		now = tk_clock_read(&tk->tkr_mono);
+		systime_snapshot->cs_id = tk->tkr_mono.clock->id;
+		systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
+		systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
+		base_real = ktime_add(tk->tkr_mono.base,
+				      tk_core.timekeeper.offs_real);
+		base_raw = tk->tkr_raw.base;
+		nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
+		nsec_raw  = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	systime_snapshot->cycles = now;
+	systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
+	systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
+}
+EXPORT_SYMBOL_GPL(ktime_get_snapshot);
+
+/* Scale base by mult/div checking for overflow */
+static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
+{
+	u64 tmp, rem;
+
+	tmp = div64_u64_rem(*base, div, &rem);
+
+	if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
+	    ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
+		return -EOVERFLOW;
+	tmp *= mult;
+
+	rem = div64_u64(rem * mult, div);
+	*base = tmp + rem;
+	return 0;
+}
+
+/**
+ * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
+ * @history:			Snapshot representing start of history
+ * @partial_history_cycles:	Cycle offset into history (fractional part)
+ * @total_history_cycles:	Total history length in cycles
+ * @discontinuity:		True indicates clock was set on history period
+ * @ts:				Cross timestamp that should be adjusted using
+ *	partial/total ratio
+ *
+ * Helper function used by get_device_system_crosststamp() to correct the
+ * crosstimestamp corresponding to the start of the current interval to the
+ * system counter value (timestamp point) provided by the driver. The
+ * total_history_* quantities are the total history starting at the provided
+ * reference point and ending at the start of the current interval. The cycle
+ * count between the driver timestamp point and the start of the current
+ * interval is partial_history_cycles.
+ */
+static int adjust_historical_crosststamp(struct system_time_snapshot *history,
+					 u64 partial_history_cycles,
+					 u64 total_history_cycles,
+					 bool discontinuity,
+					 struct system_device_crosststamp *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	u64 corr_raw, corr_real;
+	bool interp_forward;
+	int ret;
+
+	if (total_history_cycles == 0 || partial_history_cycles == 0)
+		return 0;
+
+	/* Interpolate shortest distance from beginning or end of history */
+	interp_forward = partial_history_cycles > total_history_cycles / 2;
+	partial_history_cycles = interp_forward ?
+		total_history_cycles - partial_history_cycles :
+		partial_history_cycles;
+
+	/*
+	 * Scale the monotonic raw time delta by:
+	 *	partial_history_cycles / total_history_cycles
+	 */
+	corr_raw = (u64)ktime_to_ns(
+		ktime_sub(ts->sys_monoraw, history->raw));
+	ret = scale64_check_overflow(partial_history_cycles,
+				     total_history_cycles, &corr_raw);
+	if (ret)
+		return ret;
+
+	/*
+	 * If there is a discontinuity in the history, scale monotonic raw
+	 *	correction by:
+	 *	mult(real)/mult(raw) yielding the realtime correction
+	 * Otherwise, calculate the realtime correction similar to monotonic
+	 *	raw calculation
+	 */
+	if (discontinuity) {
+		corr_real = mul_u64_u32_div
+			(corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
+	} else {
+		corr_real = (u64)ktime_to_ns(
+			ktime_sub(ts->sys_realtime, history->real));
+		ret = scale64_check_overflow(partial_history_cycles,
+					     total_history_cycles, &corr_real);
+		if (ret)
+			return ret;
+	}
+
+	/* Fixup monotonic raw and real time time values */
+	if (interp_forward) {
+		ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
+		ts->sys_realtime = ktime_add_ns(history->real, corr_real);
+	} else {
+		ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
+		ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
+	}
+
+	return 0;
+}
+
+/*
+ * cycle_between - true if test occurs chronologically between before and after
+ */
+static bool cycle_between(u64 before, u64 test, u64 after)
+{
+	if (test > before && test < after)
+		return true;
+	if (test < before && before > after)
+		return true;
+	return false;
+}
+
+/**
+ * get_device_system_crosststamp - Synchronously capture system/device timestamp
+ * @get_time_fn:	Callback to get simultaneous device time and
+ *	system counter from the device driver
+ * @ctx:		Context passed to get_time_fn()
+ * @history_begin:	Historical reference point used to interpolate system
+ *	time when counter provided by the driver is before the current interval
+ * @xtstamp:		Receives simultaneously captured system and device time
+ *
+ * Reads a timestamp from a device and correlates it to system time
+ */
+int get_device_system_crosststamp(int (*get_time_fn)
+				  (ktime_t *device_time,
+				   struct system_counterval_t *sys_counterval,
+				   void *ctx),
+				  void *ctx,
+				  struct system_time_snapshot *history_begin,
+				  struct system_device_crosststamp *xtstamp)
+{
+	struct system_counterval_t system_counterval;
+	struct timekeeper *tk = &tk_core.timekeeper;
+	u64 cycles, now, interval_start;
+	unsigned int clock_was_set_seq = 0;
+	ktime_t base_real, base_raw;
+	u64 nsec_real, nsec_raw;
+	u8 cs_was_changed_seq;
+	unsigned int seq;
+	bool do_interp;
+	int ret;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		/*
+		 * Try to synchronously capture device time and a system
+		 * counter value calling back into the device driver
+		 */
+		ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
+		if (ret)
+			return ret;
+
+		/*
+		 * Verify that the clocksource associated with the captured
+		 * system counter value is the same as the currently installed
+		 * timekeeper clocksource
+		 */
+		if (tk->tkr_mono.clock != system_counterval.cs)
+			return -ENODEV;
+		cycles = system_counterval.cycles;
+
+		/*
+		 * Check whether the system counter value provided by the
+		 * device driver is on the current timekeeping interval.
+		 */
+		now = tk_clock_read(&tk->tkr_mono);
+		interval_start = tk->tkr_mono.cycle_last;
+		if (!cycle_between(interval_start, cycles, now)) {
+			clock_was_set_seq = tk->clock_was_set_seq;
+			cs_was_changed_seq = tk->cs_was_changed_seq;
+			cycles = interval_start;
+			do_interp = true;
+		} else {
+			do_interp = false;
+		}
+
+		base_real = ktime_add(tk->tkr_mono.base,
+				      tk_core.timekeeper.offs_real);
+		base_raw = tk->tkr_raw.base;
+
+		nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
+						     system_counterval.cycles);
+		nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
+						    system_counterval.cycles);
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
+	xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);
+
+	/*
+	 * Interpolate if necessary, adjusting back from the start of the
+	 * current interval
+	 */
+	if (do_interp) {
+		u64 partial_history_cycles, total_history_cycles;
+		bool discontinuity;
+
+		/*
+		 * Check that the counter value occurs after the provided
+		 * history reference and that the history doesn't cross a
+		 * clocksource change
+		 */
+		if (!history_begin ||
+		    !cycle_between(history_begin->cycles,
+				   system_counterval.cycles, cycles) ||
+		    history_begin->cs_was_changed_seq != cs_was_changed_seq)
+			return -EINVAL;
+		partial_history_cycles = cycles - system_counterval.cycles;
+		total_history_cycles = cycles - history_begin->cycles;
+		discontinuity =
+			history_begin->clock_was_set_seq != clock_was_set_seq;
+
+		ret = adjust_historical_crosststamp(history_begin,
+						    partial_history_cycles,
+						    total_history_cycles,
+						    discontinuity, xtstamp);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(get_device_system_crosststamp);
+
+/**
+ * do_settimeofday64 - Sets the time of day.
+ * @ts:     pointer to the timespec64 variable containing the new time
+ *
+ * Sets the time of day to the new time and update NTP and notify hrtimers
+ */
+int do_settimeofday64(const struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct timespec64 ts_delta, xt;
+	unsigned long flags;
+	int ret = 0;
+
+	if (!timespec64_valid_settod(ts))
+		return -EINVAL;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	timekeeping_forward_now(tk);
+
+	xt = tk_xtime(tk);
+	ts_delta = timespec64_sub(*ts, xt);
+
+	if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
+
+	tk_set_xtime(tk, ts);
+out:
+	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	/* Signal hrtimers about time change */
+	clock_was_set(CLOCK_SET_WALL);
+
+	if (!ret) {
+		audit_tk_injoffset(ts_delta);
+		add_device_randomness(ts, sizeof(*ts));
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(do_settimeofday64);
+
+/**
+ * timekeeping_inject_offset - Adds or subtracts from the current time.
+ * @ts:		Pointer to the timespec variable containing the offset
+ *
+ * Adds or subtracts an offset value from the current time.
+ */
+static int timekeeping_inject_offset(const struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned long flags;
+	struct timespec64 tmp;
+	int ret = 0;
+
+	if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC)
+		return -EINVAL;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	timekeeping_forward_now(tk);
+
+	/* Make sure the proposed value is valid */
+	tmp = timespec64_add(tk_xtime(tk), *ts);
+	if (timespec64_compare(&tk->wall_to_monotonic, ts) > 0 ||
+	    !timespec64_valid_settod(&tmp)) {
+		ret = -EINVAL;
+		goto error;
+	}
+
+	tk_xtime_add(tk, ts);
+	tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *ts));
+
+error: /* even if we error out, we forwarded the time, so call update */
+	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	/* Signal hrtimers about time change */
+	clock_was_set(CLOCK_SET_WALL);
+
+	return ret;
+}
+
+/*
+ * Indicates if there is an offset between the system clock and the hardware
+ * clock/persistent clock/rtc.
+ */
+int persistent_clock_is_local;
+
+/*
+ * Adjust the time obtained from the CMOS to be UTC time instead of
+ * local time.
+ *
+ * This is ugly, but preferable to the alternatives.  Otherwise we
+ * would either need to write a program to do it in /etc/rc (and risk
+ * confusion if the program gets run more than once; it would also be
+ * hard to make the program warp the clock precisely n hours)  or
+ * compile in the timezone information into the kernel.  Bad, bad....
+ *
+ *						- TYT, 1992-01-01
+ *
+ * The best thing to do is to keep the CMOS clock in universal time (UTC)
+ * as real UNIX machines always do it. This avoids all headaches about
+ * daylight saving times and warping kernel clocks.
+ */
+void timekeeping_warp_clock(void)
+{
+	if (sys_tz.tz_minuteswest != 0) {
+		struct timespec64 adjust;
+
+		persistent_clock_is_local = 1;
+		adjust.tv_sec = sys_tz.tz_minuteswest * 60;
+		adjust.tv_nsec = 0;
+		timekeeping_inject_offset(&adjust);
+	}
+}
+
+/*
+ * __timekeeping_set_tai_offset - Sets the TAI offset from UTC and monotonic
+ */
+static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
+{
+	tk->tai_offset = tai_offset;
+	tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
+}
+
+/*
+ * change_clocksource - Swaps clocksources if a new one is available
+ *
+ * Accumulates current time interval and initializes new clocksource
+ */
+static int change_clocksource(void *data)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct clocksource *new, *old = NULL;
+	unsigned long flags;
+	bool change = false;
+
+	new = (struct clocksource *) data;
+
+	/*
+	 * If the cs is in module, get a module reference. Succeeds
+	 * for built-in code (owner == NULL) as well.
+	 */
+	if (try_module_get(new->owner)) {
+		if (!new->enable || new->enable(new) == 0)
+			change = true;
+		else
+			module_put(new->owner);
+	}
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	timekeeping_forward_now(tk);
+
+	if (change) {
+		old = tk->tkr_mono.clock;
+		tk_setup_internals(tk, new);
+	}
+
+	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	if (old) {
+		if (old->disable)
+			old->disable(old);
+
+		module_put(old->owner);
+	}
+
+	return 0;
+}
+
+/**
+ * timekeeping_notify - Install a new clock source
+ * @clock:		pointer to the clock source
+ *
+ * This function is called from clocksource.c after a new, better clock
+ * source has been registered. The caller holds the clocksource_mutex.
+ */
+int timekeeping_notify(struct clocksource *clock)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+
+	if (tk->tkr_mono.clock == clock)
+		return 0;
+	stop_machine(change_clocksource, clock, NULL);
+	tick_clock_notify();
+	return tk->tkr_mono.clock == clock ? 0 : -1;
+}
+
+/**
+ * ktime_get_raw_ts64 - Returns the raw monotonic time in a timespec
+ * @ts:		pointer to the timespec64 to be set
+ *
+ * Returns the raw monotonic time (completely un-modified by ntp)
+ */
+void ktime_get_raw_ts64(struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	u64 nsecs;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		ts->tv_sec = tk->raw_sec;
+		nsecs = timekeeping_get_ns(&tk->tkr_raw);
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	ts->tv_nsec = 0;
+	timespec64_add_ns(ts, nsecs);
+}
+EXPORT_SYMBOL(ktime_get_raw_ts64);
+
+
+/**
+ * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
+ */
+int timekeeping_valid_for_hres(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	int ret;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ret;
+}
+
+/**
+ * timekeeping_max_deferment - Returns max time the clocksource can be deferred
+ */
+u64 timekeeping_max_deferment(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	u64 ret;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		ret = tk->tkr_mono.clock->max_idle_ns;
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return ret;
+}
+
+/**
+ * read_persistent_clock64 -  Return time from the persistent clock.
+ * @ts: Pointer to the storage for the readout value
+ *
+ * Weak dummy function for arches that do not yet support it.
+ * Reads the time from the battery backed persistent clock.
+ * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
+ *
+ *  XXX - Do be sure to remove it once all arches implement it.
+ */
+void __weak read_persistent_clock64(struct timespec64 *ts)
+{
+	ts->tv_sec = 0;
+	ts->tv_nsec = 0;
+}
+
+/**
+ * read_persistent_wall_and_boot_offset - Read persistent clock, and also offset
+ *                                        from the boot.
+ *
+ * Weak dummy function for arches that do not yet support it.
+ * @wall_time:	- current time as returned by persistent clock
+ * @boot_offset: - offset that is defined as wall_time - boot_time
+ *
+ * The default function calculates offset based on the current value of
+ * local_clock(). This way architectures that support sched_clock() but don't
+ * support dedicated boot time clock will provide the best estimate of the
+ * boot time.
+ */
+void __weak __init
+read_persistent_wall_and_boot_offset(struct timespec64 *wall_time,
+				     struct timespec64 *boot_offset)
+{
+	read_persistent_clock64(wall_time);
+	*boot_offset = ns_to_timespec64(local_clock());
+}
+
+/*
+ * Flag reflecting whether timekeeping_resume() has injected sleeptime.
+ *
+ * The flag starts of false and is only set when a suspend reaches
+ * timekeeping_suspend(), timekeeping_resume() sets it to false when the
+ * timekeeper clocksource is not stopping across suspend and has been
+ * used to update sleep time. If the timekeeper clocksource has stopped
+ * then the flag stays true and is used by the RTC resume code to decide
+ * whether sleeptime must be injected and if so the flag gets false then.
+ *
+ * If a suspend fails before reaching timekeeping_resume() then the flag
+ * stays false and prevents erroneous sleeptime injection.
+ */
+static bool suspend_timing_needed;
+
+/* Flag for if there is a persistent clock on this platform */
+static bool persistent_clock_exists;
+
+/*
+ * timekeeping_init - Initializes the clocksource and common timekeeping values
+ */
+void __init timekeeping_init(void)
+{
+	struct timespec64 wall_time, boot_offset, wall_to_mono;
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct clocksource *clock;
+	unsigned long flags;
+
+	read_persistent_wall_and_boot_offset(&wall_time, &boot_offset);
+	if (timespec64_valid_settod(&wall_time) &&
+	    timespec64_to_ns(&wall_time) > 0) {
+		persistent_clock_exists = true;
+	} else if (timespec64_to_ns(&wall_time) != 0) {
+		pr_warn("Persistent clock returned invalid value");
+		wall_time = (struct timespec64){0};
+	}
+
+	if (timespec64_compare(&wall_time, &boot_offset) < 0)
+		boot_offset = (struct timespec64){0};
+
+	/*
+	 * We want set wall_to_mono, so the following is true:
+	 * wall time + wall_to_mono = boot time
+	 */
+	wall_to_mono = timespec64_sub(boot_offset, wall_time);
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+	ntp_init();
+
+	clock = clocksource_default_clock();
+	if (clock->enable)
+		clock->enable(clock);
+	tk_setup_internals(tk, clock);
+
+	tk_set_xtime(tk, &wall_time);
+	tk->raw_sec = 0;
+
+	tk_set_wall_to_mono(tk, wall_to_mono);
+
+	timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+}
+
+/* time in seconds when suspend began for persistent clock */
+static struct timespec64 timekeeping_suspend_time;
+
+/**
+ * __timekeeping_inject_sleeptime - Internal function to add sleep interval
+ * @tk:		Pointer to the timekeeper to be updated
+ * @delta:	Pointer to the delta value in timespec64 format
+ *
+ * Takes a timespec offset measuring a suspend interval and properly
+ * adds the sleep offset to the timekeeping variables.
+ */
+static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
+					   const struct timespec64 *delta)
+{
+	if (!timespec64_valid_strict(delta)) {
+		printk_deferred(KERN_WARNING
+				"__timekeeping_inject_sleeptime: Invalid "
+				"sleep delta value!\n");
+		return;
+	}
+	tk_xtime_add(tk, delta);
+	tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
+	tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
+	tk_debug_account_sleep_time(delta);
+}
+
+#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
+/**
+ * We have three kinds of time sources to use for sleep time
+ * injection, the preference order is:
+ * 1) non-stop clocksource
+ * 2) persistent clock (ie: RTC accessible when irqs are off)
+ * 3) RTC
+ *
+ * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
+ * If system has neither 1) nor 2), 3) will be used finally.
+ *
+ *
+ * If timekeeping has injected sleeptime via either 1) or 2),
+ * 3) becomes needless, so in this case we don't need to call
+ * rtc_resume(), and this is what timekeeping_rtc_skipresume()
+ * means.
+ */
+bool timekeeping_rtc_skipresume(void)
+{
+	return !suspend_timing_needed;
+}
+
+/**
+ * 1) can be determined whether to use or not only when doing
+ * timekeeping_resume() which is invoked after rtc_suspend(),
+ * so we can't skip rtc_suspend() surely if system has 1).
+ *
+ * But if system has 2), 2) will definitely be used, so in this
+ * case we don't need to call rtc_suspend(), and this is what
+ * timekeeping_rtc_skipsuspend() means.
+ */
+bool timekeeping_rtc_skipsuspend(void)
+{
+	return persistent_clock_exists;
+}
+
+/**
+ * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
+ * @delta: pointer to a timespec64 delta value
+ *
+ * This hook is for architectures that cannot support read_persistent_clock64
+ * because their RTC/persistent clock is only accessible when irqs are enabled.
+ * and also don't have an effective nonstop clocksource.
+ *
+ * This function should only be called by rtc_resume(), and allows
+ * a suspend offset to be injected into the timekeeping values.
+ */
+void timekeeping_inject_sleeptime64(const struct timespec64 *delta)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	suspend_timing_needed = false;
+
+	timekeeping_forward_now(tk);
+
+	__timekeeping_inject_sleeptime(tk, delta);
+
+	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	/* Signal hrtimers about time change */
+	clock_was_set(CLOCK_SET_WALL | CLOCK_SET_BOOT);
+}
+#endif
+
+/**
+ * timekeeping_resume - Resumes the generic timekeeping subsystem.
+ */
+void timekeeping_resume(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct clocksource *clock = tk->tkr_mono.clock;
+	unsigned long flags;
+	struct timespec64 ts_new, ts_delta;
+	u64 cycle_now, nsec;
+	bool inject_sleeptime = false;
+
+	read_persistent_clock64(&ts_new);
+
+	clockevents_resume();
+	clocksource_resume();
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	/*
+	 * After system resumes, we need to calculate the suspended time and
+	 * compensate it for the OS time. There are 3 sources that could be
+	 * used: Nonstop clocksource during suspend, persistent clock and rtc
+	 * device.
+	 *
+	 * One specific platform may have 1 or 2 or all of them, and the
+	 * preference will be:
+	 *	suspend-nonstop clocksource -> persistent clock -> rtc
+	 * The less preferred source will only be tried if there is no better
+	 * usable source. The rtc part is handled separately in rtc core code.
+	 */
+	cycle_now = tk_clock_read(&tk->tkr_mono);
+	nsec = clocksource_stop_suspend_timing(clock, cycle_now);
+	if (nsec > 0) {
+		ts_delta = ns_to_timespec64(nsec);
+		inject_sleeptime = true;
+	} else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
+		ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
+		inject_sleeptime = true;
+	}
+
+	if (inject_sleeptime) {
+		suspend_timing_needed = false;
+		__timekeeping_inject_sleeptime(tk, &ts_delta);
+	}
+
+	/* Re-base the last cycle value */
+	tk->tkr_mono.cycle_last = cycle_now;
+	tk->tkr_raw.cycle_last  = cycle_now;
+
+	tk->ntp_error = 0;
+	timekeeping_suspended = 0;
+	timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	touch_softlockup_watchdog();
+
+	/* Resume the clockevent device(s) and hrtimers */
+	tick_resume();
+	/* Notify timerfd as resume is equivalent to clock_was_set() */
+	timerfd_resume();
+}
+
+int timekeeping_suspend(void)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned long flags;
+	struct timespec64		delta, delta_delta;
+	static struct timespec64	old_delta;
+	struct clocksource *curr_clock;
+	u64 cycle_now;
+
+	read_persistent_clock64(&timekeeping_suspend_time);
+
+	/*
+	 * On some systems the persistent_clock can not be detected at
+	 * timekeeping_init by its return value, so if we see a valid
+	 * value returned, update the persistent_clock_exists flag.
+	 */
+	if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
+		persistent_clock_exists = true;
+
+	suspend_timing_needed = true;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+	timekeeping_forward_now(tk);
+	timekeeping_suspended = 1;
+
+	/*
+	 * Since we've called forward_now, cycle_last stores the value
+	 * just read from the current clocksource. Save this to potentially
+	 * use in suspend timing.
+	 */
+	curr_clock = tk->tkr_mono.clock;
+	cycle_now = tk->tkr_mono.cycle_last;
+	clocksource_start_suspend_timing(curr_clock, cycle_now);
+
+	if (persistent_clock_exists) {
+		/*
+		 * To avoid drift caused by repeated suspend/resumes,
+		 * which each can add ~1 second drift error,
+		 * try to compensate so the difference in system time
+		 * and persistent_clock time stays close to constant.
+		 */
+		delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
+		delta_delta = timespec64_sub(delta, old_delta);
+		if (abs(delta_delta.tv_sec) >= 2) {
+			/*
+			 * if delta_delta is too large, assume time correction
+			 * has occurred and set old_delta to the current delta.
+			 */
+			old_delta = delta;
+		} else {
+			/* Otherwise try to adjust old_system to compensate */
+			timekeeping_suspend_time =
+				timespec64_add(timekeeping_suspend_time, delta_delta);
+		}
+	}
+
+	timekeeping_update(tk, TK_MIRROR);
+	halt_fast_timekeeper(tk);
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	tick_suspend();
+	clocksource_suspend();
+	clockevents_suspend();
+
+	return 0;
+}
+
+/* sysfs resume/suspend bits for timekeeping */
+static struct syscore_ops timekeeping_syscore_ops = {
+	.resume		= timekeeping_resume,
+	.suspend	= timekeeping_suspend,
+};
+
+static int __init timekeeping_init_ops(void)
+{
+	register_syscore_ops(&timekeeping_syscore_ops);
+	return 0;
+}
+device_initcall(timekeeping_init_ops);
+
+/*
+ * Apply a multiplier adjustment to the timekeeper
+ */
+static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
+							 s64 offset,
+							 s32 mult_adj)
+{
+	s64 interval = tk->cycle_interval;
+
+	if (mult_adj == 0) {
+		return;
+	} else if (mult_adj == -1) {
+		interval = -interval;
+		offset = -offset;
+	} else if (mult_adj != 1) {
+		interval *= mult_adj;
+		offset *= mult_adj;
+	}
+
+	/*
+	 * So the following can be confusing.
+	 *
+	 * To keep things simple, lets assume mult_adj == 1 for now.
+	 *
+	 * When mult_adj != 1, remember that the interval and offset values
+	 * have been appropriately scaled so the math is the same.
+	 *
+	 * The basic idea here is that we're increasing the multiplier
+	 * by one, this causes the xtime_interval to be incremented by
+	 * one cycle_interval. This is because:
+	 *	xtime_interval = cycle_interval * mult
+	 * So if mult is being incremented by one:
+	 *	xtime_interval = cycle_interval * (mult + 1)
+	 * Its the same as:
+	 *	xtime_interval = (cycle_interval * mult) + cycle_interval
+	 * Which can be shortened to:
+	 *	xtime_interval += cycle_interval
+	 *
+	 * So offset stores the non-accumulated cycles. Thus the current
+	 * time (in shifted nanoseconds) is:
+	 *	now = (offset * adj) + xtime_nsec
+	 * Now, even though we're adjusting the clock frequency, we have
+	 * to keep time consistent. In other words, we can't jump back
+	 * in time, and we also want to avoid jumping forward in time.
+	 *
+	 * So given the same offset value, we need the time to be the same
+	 * both before and after the freq adjustment.
+	 *	now = (offset * adj_1) + xtime_nsec_1
+	 *	now = (offset * adj_2) + xtime_nsec_2
+	 * So:
+	 *	(offset * adj_1) + xtime_nsec_1 =
+	 *		(offset * adj_2) + xtime_nsec_2
+	 * And we know:
+	 *	adj_2 = adj_1 + 1
+	 * So:
+	 *	(offset * adj_1) + xtime_nsec_1 =
+	 *		(offset * (adj_1+1)) + xtime_nsec_2
+	 *	(offset * adj_1) + xtime_nsec_1 =
+	 *		(offset * adj_1) + offset + xtime_nsec_2
+	 * Canceling the sides:
+	 *	xtime_nsec_1 = offset + xtime_nsec_2
+	 * Which gives us:
+	 *	xtime_nsec_2 = xtime_nsec_1 - offset
+	 * Which simplifies to:
+	 *	xtime_nsec -= offset
+	 */
+	if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
+		/* NTP adjustment caused clocksource mult overflow */
+		WARN_ON_ONCE(1);
+		return;
+	}
+
+	tk->tkr_mono.mult += mult_adj;
+	tk->xtime_interval += interval;
+	tk->tkr_mono.xtime_nsec -= offset;
+}
+
+/*
+ * Adjust the timekeeper's multiplier to the correct frequency
+ * and also to reduce the accumulated error value.
+ */
+static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
+{
+	u32 mult;
+
+	/*
+	 * Determine the multiplier from the current NTP tick length.
+	 * Avoid expensive division when the tick length doesn't change.
+	 */
+	if (likely(tk->ntp_tick == ntp_tick_length())) {
+		mult = tk->tkr_mono.mult - tk->ntp_err_mult;
+	} else {
+		tk->ntp_tick = ntp_tick_length();
+		mult = div64_u64((tk->ntp_tick >> tk->ntp_error_shift) -
+				 tk->xtime_remainder, tk->cycle_interval);
+	}
+
+	/*
+	 * If the clock is behind the NTP time, increase the multiplier by 1
+	 * to catch up with it. If it's ahead and there was a remainder in the
+	 * tick division, the clock will slow down. Otherwise it will stay
+	 * ahead until the tick length changes to a non-divisible value.
+	 */
+	tk->ntp_err_mult = tk->ntp_error > 0 ? 1 : 0;
+	mult += tk->ntp_err_mult;
+
+	timekeeping_apply_adjustment(tk, offset, mult - tk->tkr_mono.mult);
+
+	if (unlikely(tk->tkr_mono.clock->maxadj &&
+		(abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
+			> tk->tkr_mono.clock->maxadj))) {
+		printk_once(KERN_WARNING
+			"Adjusting %s more than 11%% (%ld vs %ld)\n",
+			tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
+			(long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
+	}
+
+	/*
+	 * It may be possible that when we entered this function, xtime_nsec
+	 * was very small.  Further, if we're slightly speeding the clocksource
+	 * in the code above, its possible the required corrective factor to
+	 * xtime_nsec could cause it to underflow.
+	 *
+	 * Now, since we have already accumulated the second and the NTP
+	 * subsystem has been notified via second_overflow(), we need to skip
+	 * the next update.
+	 */
+	if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
+		tk->tkr_mono.xtime_nsec += (u64)NSEC_PER_SEC <<
+							tk->tkr_mono.shift;
+		tk->xtime_sec--;
+		tk->skip_second_overflow = 1;
+	}
+}
+
+/*
+ * accumulate_nsecs_to_secs - Accumulates nsecs into secs
+ *
+ * Helper function that accumulates the nsecs greater than a second
+ * from the xtime_nsec field to the xtime_secs field.
+ * It also calls into the NTP code to handle leapsecond processing.
+ */
+static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
+{
+	u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
+	unsigned int clock_set = 0;
+
+	while (tk->tkr_mono.xtime_nsec >= nsecps) {
+		int leap;
+
+		tk->tkr_mono.xtime_nsec -= nsecps;
+		tk->xtime_sec++;
+
+		/*
+		 * Skip NTP update if this second was accumulated before,
+		 * i.e. xtime_nsec underflowed in timekeeping_adjust()
+		 */
+		if (unlikely(tk->skip_second_overflow)) {
+			tk->skip_second_overflow = 0;
+			continue;
+		}
+
+		/* Figure out if its a leap sec and apply if needed */
+		leap = second_overflow(tk->xtime_sec);
+		if (unlikely(leap)) {
+			struct timespec64 ts;
+
+			tk->xtime_sec += leap;
+
+			ts.tv_sec = leap;
+			ts.tv_nsec = 0;
+			tk_set_wall_to_mono(tk,
+				timespec64_sub(tk->wall_to_monotonic, ts));
+
+			__timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
+
+			clock_set = TK_CLOCK_WAS_SET;
+		}
+	}
+	return clock_set;
+}
+
+/*
+ * logarithmic_accumulation - shifted accumulation of cycles
+ *
+ * This functions accumulates a shifted interval of cycles into
+ * a shifted interval nanoseconds. Allows for O(log) accumulation
+ * loop.
+ *
+ * Returns the unconsumed cycles.
+ */
+static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
+				    u32 shift, unsigned int *clock_set)
+{
+	u64 interval = tk->cycle_interval << shift;
+	u64 snsec_per_sec;
+
+	/* If the offset is smaller than a shifted interval, do nothing */
+	if (offset < interval)
+		return offset;
+
+	/* Accumulate one shifted interval */
+	offset -= interval;
+	tk->tkr_mono.cycle_last += interval;
+	tk->tkr_raw.cycle_last  += interval;
+
+	tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
+	*clock_set |= accumulate_nsecs_to_secs(tk);
+
+	/* Accumulate raw time */
+	tk->tkr_raw.xtime_nsec += tk->raw_interval << shift;
+	snsec_per_sec = (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
+	while (tk->tkr_raw.xtime_nsec >= snsec_per_sec) {
+		tk->tkr_raw.xtime_nsec -= snsec_per_sec;
+		tk->raw_sec++;
+	}
+
+	/* Accumulate error between NTP and clock interval */
+	tk->ntp_error += tk->ntp_tick << shift;
+	tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
+						(tk->ntp_error_shift + shift);
+
+	return offset;
+}
+
+/*
+ * timekeeping_advance - Updates the timekeeper to the current time and
+ * current NTP tick length
+ */
+static bool timekeeping_advance(enum timekeeping_adv_mode mode)
+{
+	struct timekeeper *real_tk = &tk_core.timekeeper;
+	struct timekeeper *tk = &shadow_timekeeper;
+	u64 offset;
+	int shift = 0, maxshift;
+	unsigned int clock_set = 0;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+
+	/* Make sure we're fully resumed: */
+	if (unlikely(timekeeping_suspended))
+		goto out;
+
+	offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
+				   tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
+
+	/* Check if there's really nothing to do */
+	if (offset < real_tk->cycle_interval && mode == TK_ADV_TICK)
+		goto out;
+
+	/* Do some additional sanity checking */
+	timekeeping_check_update(tk, offset);
+
+	/*
+	 * With NO_HZ we may have to accumulate many cycle_intervals
+	 * (think "ticks") worth of time at once. To do this efficiently,
+	 * we calculate the largest doubling multiple of cycle_intervals
+	 * that is smaller than the offset.  We then accumulate that
+	 * chunk in one go, and then try to consume the next smaller
+	 * doubled multiple.
+	 */
+	shift = ilog2(offset) - ilog2(tk->cycle_interval);
+	shift = max(0, shift);
+	/* Bound shift to one less than what overflows tick_length */
+	maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
+	shift = min(shift, maxshift);
+	while (offset >= tk->cycle_interval) {
+		offset = logarithmic_accumulation(tk, offset, shift,
+							&clock_set);
+		if (offset < tk->cycle_interval<<shift)
+			shift--;
+	}
+
+	/* Adjust the multiplier to correct NTP error */
+	timekeeping_adjust(tk, offset);
+
+	/*
+	 * Finally, make sure that after the rounding
+	 * xtime_nsec isn't larger than NSEC_PER_SEC
+	 */
+	clock_set |= accumulate_nsecs_to_secs(tk);
+
+	write_seqcount_begin(&tk_core.seq);
+	/*
+	 * Update the real timekeeper.
+	 *
+	 * We could avoid this memcpy by switching pointers, but that
+	 * requires changes to all other timekeeper usage sites as
+	 * well, i.e. move the timekeeper pointer getter into the
+	 * spinlocked/seqcount protected sections. And we trade this
+	 * memcpy under the tk_core.seq against one before we start
+	 * updating.
+	 */
+	timekeeping_update(tk, clock_set);
+	memcpy(real_tk, tk, sizeof(*tk));
+	/* The memcpy must come last. Do not put anything here! */
+	write_seqcount_end(&tk_core.seq);
+out:
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	return !!clock_set;
+}
+
+/**
+ * update_wall_time - Uses the current clocksource to increment the wall time
+ *
+ */
+void update_wall_time(void)
+{
+	if (timekeeping_advance(TK_ADV_TICK))
+		clock_was_set_delayed();
+}
+
+/**
+ * getboottime64 - Return the real time of system boot.
+ * @ts:		pointer to the timespec64 to be set
+ *
+ * Returns the wall-time of boot in a timespec64.
+ *
+ * This is based on the wall_to_monotonic offset and the total suspend
+ * time. Calls to settimeofday will affect the value returned (which
+ * basically means that however wrong your real time clock is at boot time,
+ * you get the right time here).
+ */
+void getboottime64(struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
+
+	*ts = ktime_to_timespec64(t);
+}
+EXPORT_SYMBOL_GPL(getboottime64);
+
+void ktime_get_coarse_real_ts64(struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		*ts = tk_xtime(tk);
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+}
+EXPORT_SYMBOL(ktime_get_coarse_real_ts64);
+
+void ktime_get_coarse_ts64(struct timespec64 *ts)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct timespec64 now, mono;
+	unsigned int seq;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		now = tk_xtime(tk);
+		mono = tk->wall_to_monotonic;
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	set_normalized_timespec64(ts, now.tv_sec + mono.tv_sec,
+				now.tv_nsec + mono.tv_nsec);
+}
+EXPORT_SYMBOL(ktime_get_coarse_ts64);
+
+/*
+ * Must hold jiffies_lock
+ */
+void do_timer(unsigned long ticks)
+{
+	jiffies_64 += ticks;
+	calc_global_load();
+}
+
+/**
+ * ktime_get_update_offsets_now - hrtimer helper
+ * @cwsseq:	pointer to check and store the clock was set sequence number
+ * @offs_real:	pointer to storage for monotonic -> realtime offset
+ * @offs_boot:	pointer to storage for monotonic -> boottime offset
+ * @offs_tai:	pointer to storage for monotonic -> clock tai offset
+ *
+ * Returns current monotonic time and updates the offsets if the
+ * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
+ * different.
+ *
+ * Called from hrtimer_interrupt() or retrigger_next_event()
+ */
+ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
+				     ktime_t *offs_boot, ktime_t *offs_tai)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	ktime_t base;
+	u64 nsecs;
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+
+		base = tk->tkr_mono.base;
+		nsecs = timekeeping_get_ns(&tk->tkr_mono);
+		base = ktime_add_ns(base, nsecs);
+
+		if (*cwsseq != tk->clock_was_set_seq) {
+			*cwsseq = tk->clock_was_set_seq;
+			*offs_real = tk->offs_real;
+			*offs_boot = tk->offs_boot;
+			*offs_tai = tk->offs_tai;
+		}
+
+		/* Handle leapsecond insertion adjustments */
+		if (unlikely(base >= tk->next_leap_ktime))
+			*offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0));
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return base;
+}
+
+/*
+ * timekeeping_validate_timex - Ensures the timex is ok for use in do_adjtimex
+ */
+static int timekeeping_validate_timex(const struct __kernel_timex *txc)
+{
+	if (txc->modes & ADJ_ADJTIME) {
+		/* singleshot must not be used with any other mode bits */
+		if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
+			return -EINVAL;
+		if (!(txc->modes & ADJ_OFFSET_READONLY) &&
+		    !capable(CAP_SYS_TIME))
+			return -EPERM;
+	} else {
+		/* In order to modify anything, you gotta be super-user! */
+		if (txc->modes && !capable(CAP_SYS_TIME))
+			return -EPERM;
+		/*
+		 * if the quartz is off by more than 10% then
+		 * something is VERY wrong!
+		 */
+		if (txc->modes & ADJ_TICK &&
+		    (txc->tick <  900000/USER_HZ ||
+		     txc->tick > 1100000/USER_HZ))
+			return -EINVAL;
+	}
+
+	if (txc->modes & ADJ_SETOFFSET) {
+		/* In order to inject time, you gotta be super-user! */
+		if (!capable(CAP_SYS_TIME))
+			return -EPERM;
+
+		/*
+		 * Validate if a timespec/timeval used to inject a time
+		 * offset is valid.  Offsets can be positive or negative, so
+		 * we don't check tv_sec. The value of the timeval/timespec
+		 * is the sum of its fields,but *NOTE*:
+		 * The field tv_usec/tv_nsec must always be non-negative and
+		 * we can't have more nanoseconds/microseconds than a second.
+		 */
+		if (txc->time.tv_usec < 0)
+			return -EINVAL;
+
+		if (txc->modes & ADJ_NANO) {
+			if (txc->time.tv_usec >= NSEC_PER_SEC)
+				return -EINVAL;
+		} else {
+			if (txc->time.tv_usec >= USEC_PER_SEC)
+				return -EINVAL;
+		}
+	}
+
+	/*
+	 * Check for potential multiplication overflows that can
+	 * only happen on 64-bit systems:
+	 */
+	if ((txc->modes & ADJ_FREQUENCY) && (BITS_PER_LONG == 64)) {
+		if (LLONG_MIN / PPM_SCALE > txc->freq)
+			return -EINVAL;
+		if (LLONG_MAX / PPM_SCALE < txc->freq)
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * random_get_entropy_fallback - Returns the raw clock source value,
+ * used by random.c for platforms with no valid random_get_entropy().
+ */
+unsigned long random_get_entropy_fallback(void)
+{
+	struct tk_read_base *tkr = &tk_core.timekeeper.tkr_mono;
+	struct clocksource *clock = READ_ONCE(tkr->clock);
+
+	if (unlikely(timekeeping_suspended || !clock))
+		return 0;
+	return clock->read(clock);
+}
+EXPORT_SYMBOL_GPL(random_get_entropy_fallback);
+
+/**
+ * do_adjtimex() - Accessor function to NTP __do_adjtimex function
+ */
+int do_adjtimex(struct __kernel_timex *txc)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	struct audit_ntp_data ad;
+	bool clock_set = false;
+	struct timespec64 ts;
+	unsigned long flags;
+	s32 orig_tai, tai;
+	int ret;
+
+	/* Validate the data before disabling interrupts */
+	ret = timekeeping_validate_timex(txc);
+	if (ret)
+		return ret;
+	add_device_randomness(txc, sizeof(*txc));
+
+	if (txc->modes & ADJ_SETOFFSET) {
+		struct timespec64 delta;
+		delta.tv_sec  = txc->time.tv_sec;
+		delta.tv_nsec = txc->time.tv_usec;
+		if (!(txc->modes & ADJ_NANO))
+			delta.tv_nsec *= 1000;
+		ret = timekeeping_inject_offset(&delta);
+		if (ret)
+			return ret;
+
+		audit_tk_injoffset(delta);
+	}
+
+	audit_ntp_init(&ad);
+
+	ktime_get_real_ts64(&ts);
+	add_device_randomness(&ts, sizeof(ts));
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	orig_tai = tai = tk->tai_offset;
+	ret = __do_adjtimex(txc, &ts, &tai, &ad);
+
+	if (tai != orig_tai) {
+		__timekeeping_set_tai_offset(tk, tai);
+		timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
+		clock_set = true;
+	}
+	tk_update_leap_state(tk);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	audit_ntp_log(&ad);
+
+	/* Update the multiplier immediately if frequency was set directly */
+	if (txc->modes & (ADJ_FREQUENCY | ADJ_TICK))
+		clock_set |= timekeeping_advance(TK_ADV_FREQ);
+
+	if (clock_set)
+		clock_was_set(CLOCK_REALTIME);
+
+	ntp_notify_cmos_timer();
+
+	return ret;
+}
+
+#ifdef CONFIG_NTP_PPS
+/**
+ * hardpps() - Accessor function to NTP __hardpps function
+ */
+void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	__hardpps(phase_ts, raw_ts);
+
+	write_seqcount_end(&tk_core.seq);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+}
+EXPORT_SYMBOL(hardpps);
+#endif /* CONFIG_NTP_PPS */
diff --git a/kernel/time/timekeeping.h b/kernel/time/timekeeping.h
new file mode 100644
index 000000000..543beba09
--- /dev/null
+++ b/kernel/time/timekeeping.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _KERNEL_TIME_TIMEKEEPING_H
+#define _KERNEL_TIME_TIMEKEEPING_H
+/*
+ * Internal interfaces for kernel/time/
+ */
+extern ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq,
+					    ktime_t *offs_real,
+					    ktime_t *offs_boot,
+					    ktime_t *offs_tai);
+
+extern int timekeeping_valid_for_hres(void);
+extern u64 timekeeping_max_deferment(void);
+extern void timekeeping_warp_clock(void);
+extern int timekeeping_suspend(void);
+extern void timekeeping_resume(void);
+#ifdef CONFIG_GENERIC_SCHED_CLOCK
+extern int sched_clock_suspend(void);
+extern void sched_clock_resume(void);
+#else
+static inline int sched_clock_suspend(void) { return 0; }
+static inline void sched_clock_resume(void) { }
+#endif
+
+extern void update_process_times(int user);
+extern void do_timer(unsigned long ticks);
+extern void update_wall_time(void);
+
+extern raw_spinlock_t jiffies_lock;
+extern seqcount_raw_spinlock_t jiffies_seq;
+
+#define CS_NAME_LEN	32
+
+#endif
diff --git a/kernel/time/timekeeping_debug.c b/kernel/time/timekeeping_debug.c
new file mode 100644
index 000000000..b73e8850e
--- /dev/null
+++ b/kernel/time/timekeeping_debug.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * debugfs file to track time spent in suspend
+ *
+ * Copyright (c) 2011, Google, Inc.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/seq_file.h>
+#include <linux/suspend.h>
+#include <linux/time.h>
+
+#include "timekeeping_internal.h"
+
+#define NUM_BINS 32
+
+static unsigned int sleep_time_bin[NUM_BINS] = {0};
+
+static int tk_debug_sleep_time_show(struct seq_file *s, void *data)
+{
+	unsigned int bin;
+	seq_puts(s, "      time (secs)        count\n");
+	seq_puts(s, "------------------------------\n");
+	for (bin = 0; bin < 32; bin++) {
+		if (sleep_time_bin[bin] == 0)
+			continue;
+		seq_printf(s, "%10u - %-10u %4u\n",
+			bin ? 1 << (bin - 1) : 0, 1 << bin,
+				sleep_time_bin[bin]);
+	}
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(tk_debug_sleep_time);
+
+static int __init tk_debug_sleep_time_init(void)
+{
+	debugfs_create_file("sleep_time", 0444, NULL, NULL,
+			    &tk_debug_sleep_time_fops);
+	return 0;
+}
+late_initcall(tk_debug_sleep_time_init);
+
+void tk_debug_account_sleep_time(const struct timespec64 *t)
+{
+	/* Cap bin index so we don't overflow the array */
+	int bin = min(fls(t->tv_sec), NUM_BINS-1);
+
+	sleep_time_bin[bin]++;
+	pm_deferred_pr_dbg("Timekeeping suspended for %lld.%03lu seconds\n",
+			   (s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC);
+}
+
diff --git a/kernel/time/timekeeping_internal.h b/kernel/time/timekeeping_internal.h
new file mode 100644
index 000000000..4ca2787d1
--- /dev/null
+++ b/kernel/time/timekeeping_internal.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TIMEKEEPING_INTERNAL_H
+#define _TIMEKEEPING_INTERNAL_H
+
+#include <linux/clocksource.h>
+#include <linux/spinlock.h>
+#include <linux/time.h>
+
+/*
+ * timekeeping debug functions
+ */
+#ifdef CONFIG_DEBUG_FS
+extern void tk_debug_account_sleep_time(const struct timespec64 *t);
+#else
+#define tk_debug_account_sleep_time(x)
+#endif
+
+#ifdef CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE
+static inline u64 clocksource_delta(u64 now, u64 last, u64 mask)
+{
+	u64 ret = (now - last) & mask;
+
+	/*
+	 * Prevent time going backwards by checking the MSB of mask in
+	 * the result. If set, return 0.
+	 */
+	return ret & ~(mask >> 1) ? 0 : ret;
+}
+#else
+static inline u64 clocksource_delta(u64 now, u64 last, u64 mask)
+{
+	return (now - last) & mask;
+}
+#endif
+
+/* Semi public for serialization of non timekeeper VDSO updates. */
+extern raw_spinlock_t timekeeper_lock;
+
+#endif /* _TIMEKEEPING_INTERNAL_H */
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
new file mode 100644
index 000000000..717fcb9fb
--- /dev/null
+++ b/kernel/time/timer.c
@@ -0,0 +1,2136 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Kernel internal timers
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  1997-01-28  Modified by Finn Arne Gangstad to make timers scale better.
+ *
+ *  1997-09-10  Updated NTP code according to technical memorandum Jan '96
+ *              "A Kernel Model for Precision Timekeeping" by Dave Mills
+ *  1998-12-24  Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
+ *              serialize accesses to xtime/lost_ticks).
+ *                              Copyright (C) 1998  Andrea Arcangeli
+ *  1999-03-10  Improved NTP compatibility by Ulrich Windl
+ *  2002-05-31	Move sys_sysinfo here and make its locking sane, Robert Love
+ *  2000-10-05  Implemented scalable SMP per-CPU timer handling.
+ *                              Copyright (C) 2000, 2001, 2002  Ingo Molnar
+ *              Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar
+ */
+
+#include <linux/kernel_stat.h>
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/pid_namespace.h>
+#include <linux/notifier.h>
+#include <linux/thread_info.h>
+#include <linux/time.h>
+#include <linux/jiffies.h>
+#include <linux/posix-timers.h>
+#include <linux/cpu.h>
+#include <linux/syscalls.h>
+#include <linux/delay.h>
+#include <linux/tick.h>
+#include <linux/kallsyms.h>
+#include <linux/irq_work.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/sysctl.h>
+#include <linux/sched/nohz.h>
+#include <linux/sched/debug.h>
+#include <linux/slab.h>
+#include <linux/compat.h>
+#include <linux/random.h>
+#include <linux/sysctl.h>
+
+#include <linux/uaccess.h>
+#include <asm/unistd.h>
+#include <asm/div64.h>
+#include <asm/timex.h>
+#include <asm/io.h>
+
+#include "tick-internal.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/timer.h>
+
+__visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
+
+EXPORT_SYMBOL(jiffies_64);
+
+/*
+ * The timer wheel has LVL_DEPTH array levels. Each level provides an array of
+ * LVL_SIZE buckets. Each level is driven by its own clock and therefor each
+ * level has a different granularity.
+ *
+ * The level granularity is:		LVL_CLK_DIV ^ lvl
+ * The level clock frequency is:	HZ / (LVL_CLK_DIV ^ level)
+ *
+ * The array level of a newly armed timer depends on the relative expiry
+ * time. The farther the expiry time is away the higher the array level and
+ * therefor the granularity becomes.
+ *
+ * Contrary to the original timer wheel implementation, which aims for 'exact'
+ * expiry of the timers, this implementation removes the need for recascading
+ * the timers into the lower array levels. The previous 'classic' timer wheel
+ * implementation of the kernel already violated the 'exact' expiry by adding
+ * slack to the expiry time to provide batched expiration. The granularity
+ * levels provide implicit batching.
+ *
+ * This is an optimization of the original timer wheel implementation for the
+ * majority of the timer wheel use cases: timeouts. The vast majority of
+ * timeout timers (networking, disk I/O ...) are canceled before expiry. If
+ * the timeout expires it indicates that normal operation is disturbed, so it
+ * does not matter much whether the timeout comes with a slight delay.
+ *
+ * The only exception to this are networking timers with a small expiry
+ * time. They rely on the granularity. Those fit into the first wheel level,
+ * which has HZ granularity.
+ *
+ * We don't have cascading anymore. timers with a expiry time above the
+ * capacity of the last wheel level are force expired at the maximum timeout
+ * value of the last wheel level. From data sampling we know that the maximum
+ * value observed is 5 days (network connection tracking), so this should not
+ * be an issue.
+ *
+ * The currently chosen array constants values are a good compromise between
+ * array size and granularity.
+ *
+ * This results in the following granularity and range levels:
+ *
+ * HZ 1000 steps
+ * Level Offset  Granularity            Range
+ *  0      0         1 ms                0 ms -         63 ms
+ *  1     64         8 ms               64 ms -        511 ms
+ *  2    128        64 ms              512 ms -       4095 ms (512ms - ~4s)
+ *  3    192       512 ms             4096 ms -      32767 ms (~4s - ~32s)
+ *  4    256      4096 ms (~4s)      32768 ms -     262143 ms (~32s - ~4m)
+ *  5    320     32768 ms (~32s)    262144 ms -    2097151 ms (~4m - ~34m)
+ *  6    384    262144 ms (~4m)    2097152 ms -   16777215 ms (~34m - ~4h)
+ *  7    448   2097152 ms (~34m)  16777216 ms -  134217727 ms (~4h - ~1d)
+ *  8    512  16777216 ms (~4h)  134217728 ms - 1073741822 ms (~1d - ~12d)
+ *
+ * HZ  300
+ * Level Offset  Granularity            Range
+ *  0	   0         3 ms                0 ms -        210 ms
+ *  1	  64        26 ms              213 ms -       1703 ms (213ms - ~1s)
+ *  2	 128       213 ms             1706 ms -      13650 ms (~1s - ~13s)
+ *  3	 192      1706 ms (~1s)      13653 ms -     109223 ms (~13s - ~1m)
+ *  4	 256     13653 ms (~13s)    109226 ms -     873810 ms (~1m - ~14m)
+ *  5	 320    109226 ms (~1m)     873813 ms -    6990503 ms (~14m - ~1h)
+ *  6	 384    873813 ms (~14m)   6990506 ms -   55924050 ms (~1h - ~15h)
+ *  7	 448   6990506 ms (~1h)   55924053 ms -  447392423 ms (~15h - ~5d)
+ *  8    512  55924053 ms (~15h) 447392426 ms - 3579139406 ms (~5d - ~41d)
+ *
+ * HZ  250
+ * Level Offset  Granularity            Range
+ *  0	   0         4 ms                0 ms -        255 ms
+ *  1	  64        32 ms              256 ms -       2047 ms (256ms - ~2s)
+ *  2	 128       256 ms             2048 ms -      16383 ms (~2s - ~16s)
+ *  3	 192      2048 ms (~2s)      16384 ms -     131071 ms (~16s - ~2m)
+ *  4	 256     16384 ms (~16s)    131072 ms -    1048575 ms (~2m - ~17m)
+ *  5	 320    131072 ms (~2m)    1048576 ms -    8388607 ms (~17m - ~2h)
+ *  6	 384   1048576 ms (~17m)   8388608 ms -   67108863 ms (~2h - ~18h)
+ *  7	 448   8388608 ms (~2h)   67108864 ms -  536870911 ms (~18h - ~6d)
+ *  8    512  67108864 ms (~18h) 536870912 ms - 4294967288 ms (~6d - ~49d)
+ *
+ * HZ  100
+ * Level Offset  Granularity            Range
+ *  0	   0         10 ms               0 ms -        630 ms
+ *  1	  64         80 ms             640 ms -       5110 ms (640ms - ~5s)
+ *  2	 128        640 ms            5120 ms -      40950 ms (~5s - ~40s)
+ *  3	 192       5120 ms (~5s)     40960 ms -     327670 ms (~40s - ~5m)
+ *  4	 256      40960 ms (~40s)   327680 ms -    2621430 ms (~5m - ~43m)
+ *  5	 320     327680 ms (~5m)   2621440 ms -   20971510 ms (~43m - ~5h)
+ *  6	 384    2621440 ms (~43m) 20971520 ms -  167772150 ms (~5h - ~1d)
+ *  7	 448   20971520 ms (~5h) 167772160 ms - 1342177270 ms (~1d - ~15d)
+ */
+
+/* Clock divisor for the next level */
+#define LVL_CLK_SHIFT	3
+#define LVL_CLK_DIV	(1UL << LVL_CLK_SHIFT)
+#define LVL_CLK_MASK	(LVL_CLK_DIV - 1)
+#define LVL_SHIFT(n)	((n) * LVL_CLK_SHIFT)
+#define LVL_GRAN(n)	(1UL << LVL_SHIFT(n))
+
+/*
+ * The time start value for each level to select the bucket at enqueue
+ * time. We start from the last possible delta of the previous level
+ * so that we can later add an extra LVL_GRAN(n) to n (see calc_index()).
+ */
+#define LVL_START(n)	((LVL_SIZE - 1) << (((n) - 1) * LVL_CLK_SHIFT))
+
+/* Size of each clock level */
+#define LVL_BITS	6
+#define LVL_SIZE	(1UL << LVL_BITS)
+#define LVL_MASK	(LVL_SIZE - 1)
+#define LVL_OFFS(n)	((n) * LVL_SIZE)
+
+/* Level depth */
+#if HZ > 100
+# define LVL_DEPTH	9
+# else
+# define LVL_DEPTH	8
+#endif
+
+/* The cutoff (max. capacity of the wheel) */
+#define WHEEL_TIMEOUT_CUTOFF	(LVL_START(LVL_DEPTH))
+#define WHEEL_TIMEOUT_MAX	(WHEEL_TIMEOUT_CUTOFF - LVL_GRAN(LVL_DEPTH - 1))
+
+/*
+ * The resulting wheel size. If NOHZ is configured we allocate two
+ * wheels so we have a separate storage for the deferrable timers.
+ */
+#define WHEEL_SIZE	(LVL_SIZE * LVL_DEPTH)
+
+#ifdef CONFIG_NO_HZ_COMMON
+# define NR_BASES	2
+# define BASE_STD	0
+# define BASE_DEF	1
+#else
+# define NR_BASES	1
+# define BASE_STD	0
+# define BASE_DEF	0
+#endif
+
+struct timer_base {
+	raw_spinlock_t		lock;
+	struct timer_list	*running_timer;
+#ifdef CONFIG_PREEMPT_RT
+	spinlock_t		expiry_lock;
+	atomic_t		timer_waiters;
+#endif
+	unsigned long		clk;
+	unsigned long		next_expiry;
+	unsigned int		cpu;
+	bool			next_expiry_recalc;
+	bool			is_idle;
+	bool			timers_pending;
+	DECLARE_BITMAP(pending_map, WHEEL_SIZE);
+	struct hlist_head	vectors[WHEEL_SIZE];
+} ____cacheline_aligned;
+
+static DEFINE_PER_CPU(struct timer_base, timer_bases[NR_BASES]);
+
+#ifdef CONFIG_NO_HZ_COMMON
+
+static DEFINE_STATIC_KEY_FALSE(timers_nohz_active);
+static DEFINE_MUTEX(timer_keys_mutex);
+
+static void timer_update_keys(struct work_struct *work);
+static DECLARE_WORK(timer_update_work, timer_update_keys);
+
+#ifdef CONFIG_SMP
+static unsigned int sysctl_timer_migration = 1;
+
+DEFINE_STATIC_KEY_FALSE(timers_migration_enabled);
+
+static void timers_update_migration(void)
+{
+	if (sysctl_timer_migration && tick_nohz_active)
+		static_branch_enable(&timers_migration_enabled);
+	else
+		static_branch_disable(&timers_migration_enabled);
+}
+
+#ifdef CONFIG_SYSCTL
+static int timer_migration_handler(struct ctl_table *table, int write,
+			    void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int ret;
+
+	mutex_lock(&timer_keys_mutex);
+	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+	if (!ret && write)
+		timers_update_migration();
+	mutex_unlock(&timer_keys_mutex);
+	return ret;
+}
+
+static struct ctl_table timer_sysctl[] = {
+	{
+		.procname	= "timer_migration",
+		.data		= &sysctl_timer_migration,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= timer_migration_handler,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{}
+};
+
+static int __init timer_sysctl_init(void)
+{
+	register_sysctl("kernel", timer_sysctl);
+	return 0;
+}
+device_initcall(timer_sysctl_init);
+#endif /* CONFIG_SYSCTL */
+#else /* CONFIG_SMP */
+static inline void timers_update_migration(void) { }
+#endif /* !CONFIG_SMP */
+
+static void timer_update_keys(struct work_struct *work)
+{
+	mutex_lock(&timer_keys_mutex);
+	timers_update_migration();
+	static_branch_enable(&timers_nohz_active);
+	mutex_unlock(&timer_keys_mutex);
+}
+
+void timers_update_nohz(void)
+{
+	schedule_work(&timer_update_work);
+}
+
+static inline bool is_timers_nohz_active(void)
+{
+	return static_branch_unlikely(&timers_nohz_active);
+}
+#else
+static inline bool is_timers_nohz_active(void) { return false; }
+#endif /* NO_HZ_COMMON */
+
+static unsigned long round_jiffies_common(unsigned long j, int cpu,
+		bool force_up)
+{
+	int rem;
+	unsigned long original = j;
+
+	/*
+	 * We don't want all cpus firing their timers at once hitting the
+	 * same lock or cachelines, so we skew each extra cpu with an extra
+	 * 3 jiffies. This 3 jiffies came originally from the mm/ code which
+	 * already did this.
+	 * The skew is done by adding 3*cpunr, then round, then subtract this
+	 * extra offset again.
+	 */
+	j += cpu * 3;
+
+	rem = j % HZ;
+
+	/*
+	 * If the target jiffie is just after a whole second (which can happen
+	 * due to delays of the timer irq, long irq off times etc etc) then
+	 * we should round down to the whole second, not up. Use 1/4th second
+	 * as cutoff for this rounding as an extreme upper bound for this.
+	 * But never round down if @force_up is set.
+	 */
+	if (rem < HZ/4 && !force_up) /* round down */
+		j = j - rem;
+	else /* round up */
+		j = j - rem + HZ;
+
+	/* now that we have rounded, subtract the extra skew again */
+	j -= cpu * 3;
+
+	/*
+	 * Make sure j is still in the future. Otherwise return the
+	 * unmodified value.
+	 */
+	return time_is_after_jiffies(j) ? j : original;
+}
+
+/**
+ * __round_jiffies - function to round jiffies to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * __round_jiffies() rounds an absolute time in the future (in jiffies)
+ * up or down to (approximately) full seconds. This is useful for timers
+ * for which the exact time they fire does not matter too much, as long as
+ * they fire approximately every X seconds.
+ *
+ * By rounding these timers to whole seconds, all such timers will fire
+ * at the same time, rather than at various times spread out. The goal
+ * of this is to have the CPU wake up less, which saves power.
+ *
+ * The exact rounding is skewed for each processor to avoid all
+ * processors firing at the exact same time, which could lead
+ * to lock contention or spurious cache line bouncing.
+ *
+ * The return value is the rounded version of the @j parameter.
+ */
+unsigned long __round_jiffies(unsigned long j, int cpu)
+{
+	return round_jiffies_common(j, cpu, false);
+}
+EXPORT_SYMBOL_GPL(__round_jiffies);
+
+/**
+ * __round_jiffies_relative - function to round jiffies to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * __round_jiffies_relative() rounds a time delta  in the future (in jiffies)
+ * up or down to (approximately) full seconds. This is useful for timers
+ * for which the exact time they fire does not matter too much, as long as
+ * they fire approximately every X seconds.
+ *
+ * By rounding these timers to whole seconds, all such timers will fire
+ * at the same time, rather than at various times spread out. The goal
+ * of this is to have the CPU wake up less, which saves power.
+ *
+ * The exact rounding is skewed for each processor to avoid all
+ * processors firing at the exact same time, which could lead
+ * to lock contention or spurious cache line bouncing.
+ *
+ * The return value is the rounded version of the @j parameter.
+ */
+unsigned long __round_jiffies_relative(unsigned long j, int cpu)
+{
+	unsigned long j0 = jiffies;
+
+	/* Use j0 because jiffies might change while we run */
+	return round_jiffies_common(j + j0, cpu, false) - j0;
+}
+EXPORT_SYMBOL_GPL(__round_jiffies_relative);
+
+/**
+ * round_jiffies - function to round jiffies to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ *
+ * round_jiffies() rounds an absolute time in the future (in jiffies)
+ * up or down to (approximately) full seconds. This is useful for timers
+ * for which the exact time they fire does not matter too much, as long as
+ * they fire approximately every X seconds.
+ *
+ * By rounding these timers to whole seconds, all such timers will fire
+ * at the same time, rather than at various times spread out. The goal
+ * of this is to have the CPU wake up less, which saves power.
+ *
+ * The return value is the rounded version of the @j parameter.
+ */
+unsigned long round_jiffies(unsigned long j)
+{
+	return round_jiffies_common(j, raw_smp_processor_id(), false);
+}
+EXPORT_SYMBOL_GPL(round_jiffies);
+
+/**
+ * round_jiffies_relative - function to round jiffies to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ *
+ * round_jiffies_relative() rounds a time delta  in the future (in jiffies)
+ * up or down to (approximately) full seconds. This is useful for timers
+ * for which the exact time they fire does not matter too much, as long as
+ * they fire approximately every X seconds.
+ *
+ * By rounding these timers to whole seconds, all such timers will fire
+ * at the same time, rather than at various times spread out. The goal
+ * of this is to have the CPU wake up less, which saves power.
+ *
+ * The return value is the rounded version of the @j parameter.
+ */
+unsigned long round_jiffies_relative(unsigned long j)
+{
+	return __round_jiffies_relative(j, raw_smp_processor_id());
+}
+EXPORT_SYMBOL_GPL(round_jiffies_relative);
+
+/**
+ * __round_jiffies_up - function to round jiffies up to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * This is the same as __round_jiffies() except that it will never
+ * round down.  This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long __round_jiffies_up(unsigned long j, int cpu)
+{
+	return round_jiffies_common(j, cpu, true);
+}
+EXPORT_SYMBOL_GPL(__round_jiffies_up);
+
+/**
+ * __round_jiffies_up_relative - function to round jiffies up to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ * @cpu: the processor number on which the timeout will happen
+ *
+ * This is the same as __round_jiffies_relative() except that it will never
+ * round down.  This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long __round_jiffies_up_relative(unsigned long j, int cpu)
+{
+	unsigned long j0 = jiffies;
+
+	/* Use j0 because jiffies might change while we run */
+	return round_jiffies_common(j + j0, cpu, true) - j0;
+}
+EXPORT_SYMBOL_GPL(__round_jiffies_up_relative);
+
+/**
+ * round_jiffies_up - function to round jiffies up to a full second
+ * @j: the time in (absolute) jiffies that should be rounded
+ *
+ * This is the same as round_jiffies() except that it will never
+ * round down.  This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long round_jiffies_up(unsigned long j)
+{
+	return round_jiffies_common(j, raw_smp_processor_id(), true);
+}
+EXPORT_SYMBOL_GPL(round_jiffies_up);
+
+/**
+ * round_jiffies_up_relative - function to round jiffies up to a full second
+ * @j: the time in (relative) jiffies that should be rounded
+ *
+ * This is the same as round_jiffies_relative() except that it will never
+ * round down.  This is useful for timeouts for which the exact time
+ * of firing does not matter too much, as long as they don't fire too
+ * early.
+ */
+unsigned long round_jiffies_up_relative(unsigned long j)
+{
+	return __round_jiffies_up_relative(j, raw_smp_processor_id());
+}
+EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
+
+
+static inline unsigned int timer_get_idx(struct timer_list *timer)
+{
+	return (timer->flags & TIMER_ARRAYMASK) >> TIMER_ARRAYSHIFT;
+}
+
+static inline void timer_set_idx(struct timer_list *timer, unsigned int idx)
+{
+	timer->flags = (timer->flags & ~TIMER_ARRAYMASK) |
+			idx << TIMER_ARRAYSHIFT;
+}
+
+/*
+ * Helper function to calculate the array index for a given expiry
+ * time.
+ */
+static inline unsigned calc_index(unsigned long expires, unsigned lvl,
+				  unsigned long *bucket_expiry)
+{
+
+	/*
+	 * The timer wheel has to guarantee that a timer does not fire
+	 * early. Early expiry can happen due to:
+	 * - Timer is armed at the edge of a tick
+	 * - Truncation of the expiry time in the outer wheel levels
+	 *
+	 * Round up with level granularity to prevent this.
+	 */
+	expires = (expires >> LVL_SHIFT(lvl)) + 1;
+	*bucket_expiry = expires << LVL_SHIFT(lvl);
+	return LVL_OFFS(lvl) + (expires & LVL_MASK);
+}
+
+static int calc_wheel_index(unsigned long expires, unsigned long clk,
+			    unsigned long *bucket_expiry)
+{
+	unsigned long delta = expires - clk;
+	unsigned int idx;
+
+	if (delta < LVL_START(1)) {
+		idx = calc_index(expires, 0, bucket_expiry);
+	} else if (delta < LVL_START(2)) {
+		idx = calc_index(expires, 1, bucket_expiry);
+	} else if (delta < LVL_START(3)) {
+		idx = calc_index(expires, 2, bucket_expiry);
+	} else if (delta < LVL_START(4)) {
+		idx = calc_index(expires, 3, bucket_expiry);
+	} else if (delta < LVL_START(5)) {
+		idx = calc_index(expires, 4, bucket_expiry);
+	} else if (delta < LVL_START(6)) {
+		idx = calc_index(expires, 5, bucket_expiry);
+	} else if (delta < LVL_START(7)) {
+		idx = calc_index(expires, 6, bucket_expiry);
+	} else if (LVL_DEPTH > 8 && delta < LVL_START(8)) {
+		idx = calc_index(expires, 7, bucket_expiry);
+	} else if ((long) delta < 0) {
+		idx = clk & LVL_MASK;
+		*bucket_expiry = clk;
+	} else {
+		/*
+		 * Force expire obscene large timeouts to expire at the
+		 * capacity limit of the wheel.
+		 */
+		if (delta >= WHEEL_TIMEOUT_CUTOFF)
+			expires = clk + WHEEL_TIMEOUT_MAX;
+
+		idx = calc_index(expires, LVL_DEPTH - 1, bucket_expiry);
+	}
+	return idx;
+}
+
+static void
+trigger_dyntick_cpu(struct timer_base *base, struct timer_list *timer)
+{
+	if (!is_timers_nohz_active())
+		return;
+
+	/*
+	 * TODO: This wants some optimizing similar to the code below, but we
+	 * will do that when we switch from push to pull for deferrable timers.
+	 */
+	if (timer->flags & TIMER_DEFERRABLE) {
+		if (tick_nohz_full_cpu(base->cpu))
+			wake_up_nohz_cpu(base->cpu);
+		return;
+	}
+
+	/*
+	 * We might have to IPI the remote CPU if the base is idle and the
+	 * timer is not deferrable. If the other CPU is on the way to idle
+	 * then it can't set base->is_idle as we hold the base lock:
+	 */
+	if (base->is_idle)
+		wake_up_nohz_cpu(base->cpu);
+}
+
+/*
+ * Enqueue the timer into the hash bucket, mark it pending in
+ * the bitmap, store the index in the timer flags then wake up
+ * the target CPU if needed.
+ */
+static void enqueue_timer(struct timer_base *base, struct timer_list *timer,
+			  unsigned int idx, unsigned long bucket_expiry)
+{
+
+	hlist_add_head(&timer->entry, base->vectors + idx);
+	__set_bit(idx, base->pending_map);
+	timer_set_idx(timer, idx);
+
+	trace_timer_start(timer, timer->expires, timer->flags);
+
+	/*
+	 * Check whether this is the new first expiring timer. The
+	 * effective expiry time of the timer is required here
+	 * (bucket_expiry) instead of timer->expires.
+	 */
+	if (time_before(bucket_expiry, base->next_expiry)) {
+		/*
+		 * Set the next expiry time and kick the CPU so it
+		 * can reevaluate the wheel:
+		 */
+		base->next_expiry = bucket_expiry;
+		base->timers_pending = true;
+		base->next_expiry_recalc = false;
+		trigger_dyntick_cpu(base, timer);
+	}
+}
+
+static void internal_add_timer(struct timer_base *base, struct timer_list *timer)
+{
+	unsigned long bucket_expiry;
+	unsigned int idx;
+
+	idx = calc_wheel_index(timer->expires, base->clk, &bucket_expiry);
+	enqueue_timer(base, timer, idx, bucket_expiry);
+}
+
+#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
+
+static const struct debug_obj_descr timer_debug_descr;
+
+struct timer_hint {
+	void	(*function)(struct timer_list *t);
+	long	offset;
+};
+
+#define TIMER_HINT(fn, container, timr, hintfn)			\
+	{							\
+		.function = fn,					\
+		.offset	  = offsetof(container, hintfn) -	\
+			    offsetof(container, timr)		\
+	}
+
+static const struct timer_hint timer_hints[] = {
+	TIMER_HINT(delayed_work_timer_fn,
+		   struct delayed_work, timer, work.func),
+	TIMER_HINT(kthread_delayed_work_timer_fn,
+		   struct kthread_delayed_work, timer, work.func),
+};
+
+static void *timer_debug_hint(void *addr)
+{
+	struct timer_list *timer = addr;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(timer_hints); i++) {
+		if (timer_hints[i].function == timer->function) {
+			void (**fn)(void) = addr + timer_hints[i].offset;
+
+			return *fn;
+		}
+	}
+
+	return timer->function;
+}
+
+static bool timer_is_static_object(void *addr)
+{
+	struct timer_list *timer = addr;
+
+	return (timer->entry.pprev == NULL &&
+		timer->entry.next == TIMER_ENTRY_STATIC);
+}
+
+/*
+ * fixup_init is called when:
+ * - an active object is initialized
+ */
+static bool timer_fixup_init(void *addr, enum debug_obj_state state)
+{
+	struct timer_list *timer = addr;
+
+	switch (state) {
+	case ODEBUG_STATE_ACTIVE:
+		del_timer_sync(timer);
+		debug_object_init(timer, &timer_debug_descr);
+		return true;
+	default:
+		return false;
+	}
+}
+
+/* Stub timer callback for improperly used timers. */
+static void stub_timer(struct timer_list *unused)
+{
+	WARN_ON(1);
+}
+
+/*
+ * fixup_activate is called when:
+ * - an active object is activated
+ * - an unknown non-static object is activated
+ */
+static bool timer_fixup_activate(void *addr, enum debug_obj_state state)
+{
+	struct timer_list *timer = addr;
+
+	switch (state) {
+	case ODEBUG_STATE_NOTAVAILABLE:
+		timer_setup(timer, stub_timer, 0);
+		return true;
+
+	case ODEBUG_STATE_ACTIVE:
+		WARN_ON(1);
+		fallthrough;
+	default:
+		return false;
+	}
+}
+
+/*
+ * fixup_free is called when:
+ * - an active object is freed
+ */
+static bool timer_fixup_free(void *addr, enum debug_obj_state state)
+{
+	struct timer_list *timer = addr;
+
+	switch (state) {
+	case ODEBUG_STATE_ACTIVE:
+		del_timer_sync(timer);
+		debug_object_free(timer, &timer_debug_descr);
+		return true;
+	default:
+		return false;
+	}
+}
+
+/*
+ * fixup_assert_init is called when:
+ * - an untracked/uninit-ed object is found
+ */
+static bool timer_fixup_assert_init(void *addr, enum debug_obj_state state)
+{
+	struct timer_list *timer = addr;
+
+	switch (state) {
+	case ODEBUG_STATE_NOTAVAILABLE:
+		timer_setup(timer, stub_timer, 0);
+		return true;
+	default:
+		return false;
+	}
+}
+
+static const struct debug_obj_descr timer_debug_descr = {
+	.name			= "timer_list",
+	.debug_hint		= timer_debug_hint,
+	.is_static_object	= timer_is_static_object,
+	.fixup_init		= timer_fixup_init,
+	.fixup_activate		= timer_fixup_activate,
+	.fixup_free		= timer_fixup_free,
+	.fixup_assert_init	= timer_fixup_assert_init,
+};
+
+static inline void debug_timer_init(struct timer_list *timer)
+{
+	debug_object_init(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_activate(struct timer_list *timer)
+{
+	debug_object_activate(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_deactivate(struct timer_list *timer)
+{
+	debug_object_deactivate(timer, &timer_debug_descr);
+}
+
+static inline void debug_timer_assert_init(struct timer_list *timer)
+{
+	debug_object_assert_init(timer, &timer_debug_descr);
+}
+
+static void do_init_timer(struct timer_list *timer,
+			  void (*func)(struct timer_list *),
+			  unsigned int flags,
+			  const char *name, struct lock_class_key *key);
+
+void init_timer_on_stack_key(struct timer_list *timer,
+			     void (*func)(struct timer_list *),
+			     unsigned int flags,
+			     const char *name, struct lock_class_key *key)
+{
+	debug_object_init_on_stack(timer, &timer_debug_descr);
+	do_init_timer(timer, func, flags, name, key);
+}
+EXPORT_SYMBOL_GPL(init_timer_on_stack_key);
+
+void destroy_timer_on_stack(struct timer_list *timer)
+{
+	debug_object_free(timer, &timer_debug_descr);
+}
+EXPORT_SYMBOL_GPL(destroy_timer_on_stack);
+
+#else
+static inline void debug_timer_init(struct timer_list *timer) { }
+static inline void debug_timer_activate(struct timer_list *timer) { }
+static inline void debug_timer_deactivate(struct timer_list *timer) { }
+static inline void debug_timer_assert_init(struct timer_list *timer) { }
+#endif
+
+static inline void debug_init(struct timer_list *timer)
+{
+	debug_timer_init(timer);
+	trace_timer_init(timer);
+}
+
+static inline void debug_deactivate(struct timer_list *timer)
+{
+	debug_timer_deactivate(timer);
+	trace_timer_cancel(timer);
+}
+
+static inline void debug_assert_init(struct timer_list *timer)
+{
+	debug_timer_assert_init(timer);
+}
+
+static void do_init_timer(struct timer_list *timer,
+			  void (*func)(struct timer_list *),
+			  unsigned int flags,
+			  const char *name, struct lock_class_key *key)
+{
+	timer->entry.pprev = NULL;
+	timer->function = func;
+	if (WARN_ON_ONCE(flags & ~TIMER_INIT_FLAGS))
+		flags &= TIMER_INIT_FLAGS;
+	timer->flags = flags | raw_smp_processor_id();
+	lockdep_init_map(&timer->lockdep_map, name, key, 0);
+}
+
+/**
+ * init_timer_key - initialize a timer
+ * @timer: the timer to be initialized
+ * @func: timer callback function
+ * @flags: timer flags
+ * @name: name of the timer
+ * @key: lockdep class key of the fake lock used for tracking timer
+ *       sync lock dependencies
+ *
+ * init_timer_key() must be done to a timer prior calling *any* of the
+ * other timer functions.
+ */
+void init_timer_key(struct timer_list *timer,
+		    void (*func)(struct timer_list *), unsigned int flags,
+		    const char *name, struct lock_class_key *key)
+{
+	debug_init(timer);
+	do_init_timer(timer, func, flags, name, key);
+}
+EXPORT_SYMBOL(init_timer_key);
+
+static inline void detach_timer(struct timer_list *timer, bool clear_pending)
+{
+	struct hlist_node *entry = &timer->entry;
+
+	debug_deactivate(timer);
+
+	__hlist_del(entry);
+	if (clear_pending)
+		entry->pprev = NULL;
+	entry->next = LIST_POISON2;
+}
+
+static int detach_if_pending(struct timer_list *timer, struct timer_base *base,
+			     bool clear_pending)
+{
+	unsigned idx = timer_get_idx(timer);
+
+	if (!timer_pending(timer))
+		return 0;
+
+	if (hlist_is_singular_node(&timer->entry, base->vectors + idx)) {
+		__clear_bit(idx, base->pending_map);
+		base->next_expiry_recalc = true;
+	}
+
+	detach_timer(timer, clear_pending);
+	return 1;
+}
+
+static inline struct timer_base *get_timer_cpu_base(u32 tflags, u32 cpu)
+{
+	struct timer_base *base = per_cpu_ptr(&timer_bases[BASE_STD], cpu);
+
+	/*
+	 * If the timer is deferrable and NO_HZ_COMMON is set then we need
+	 * to use the deferrable base.
+	 */
+	if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && (tflags & TIMER_DEFERRABLE))
+		base = per_cpu_ptr(&timer_bases[BASE_DEF], cpu);
+	return base;
+}
+
+static inline struct timer_base *get_timer_this_cpu_base(u32 tflags)
+{
+	struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+
+	/*
+	 * If the timer is deferrable and NO_HZ_COMMON is set then we need
+	 * to use the deferrable base.
+	 */
+	if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && (tflags & TIMER_DEFERRABLE))
+		base = this_cpu_ptr(&timer_bases[BASE_DEF]);
+	return base;
+}
+
+static inline struct timer_base *get_timer_base(u32 tflags)
+{
+	return get_timer_cpu_base(tflags, tflags & TIMER_CPUMASK);
+}
+
+static inline struct timer_base *
+get_target_base(struct timer_base *base, unsigned tflags)
+{
+#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
+	if (static_branch_likely(&timers_migration_enabled) &&
+	    !(tflags & TIMER_PINNED))
+		return get_timer_cpu_base(tflags, get_nohz_timer_target());
+#endif
+	return get_timer_this_cpu_base(tflags);
+}
+
+static inline void forward_timer_base(struct timer_base *base)
+{
+	unsigned long jnow = READ_ONCE(jiffies);
+
+	/*
+	 * No need to forward if we are close enough below jiffies.
+	 * Also while executing timers, base->clk is 1 offset ahead
+	 * of jiffies to avoid endless requeuing to current jiffies.
+	 */
+	if ((long)(jnow - base->clk) < 1)
+		return;
+
+	/*
+	 * If the next expiry value is > jiffies, then we fast forward to
+	 * jiffies otherwise we forward to the next expiry value.
+	 */
+	if (time_after(base->next_expiry, jnow)) {
+		base->clk = jnow;
+	} else {
+		if (WARN_ON_ONCE(time_before(base->next_expiry, base->clk)))
+			return;
+		base->clk = base->next_expiry;
+	}
+}
+
+
+/*
+ * We are using hashed locking: Holding per_cpu(timer_bases[x]).lock means
+ * that all timers which are tied to this base are locked, and the base itself
+ * is locked too.
+ *
+ * So __run_timers/migrate_timers can safely modify all timers which could
+ * be found in the base->vectors array.
+ *
+ * When a timer is migrating then the TIMER_MIGRATING flag is set and we need
+ * to wait until the migration is done.
+ */
+static struct timer_base *lock_timer_base(struct timer_list *timer,
+					  unsigned long *flags)
+	__acquires(timer->base->lock)
+{
+	for (;;) {
+		struct timer_base *base;
+		u32 tf;
+
+		/*
+		 * We need to use READ_ONCE() here, otherwise the compiler
+		 * might re-read @tf between the check for TIMER_MIGRATING
+		 * and spin_lock().
+		 */
+		tf = READ_ONCE(timer->flags);
+
+		if (!(tf & TIMER_MIGRATING)) {
+			base = get_timer_base(tf);
+			raw_spin_lock_irqsave(&base->lock, *flags);
+			if (timer->flags == tf)
+				return base;
+			raw_spin_unlock_irqrestore(&base->lock, *flags);
+		}
+		cpu_relax();
+	}
+}
+
+#define MOD_TIMER_PENDING_ONLY		0x01
+#define MOD_TIMER_REDUCE		0x02
+#define MOD_TIMER_NOTPENDING		0x04
+
+static inline int
+__mod_timer(struct timer_list *timer, unsigned long expires, unsigned int options)
+{
+	unsigned long clk = 0, flags, bucket_expiry;
+	struct timer_base *base, *new_base;
+	unsigned int idx = UINT_MAX;
+	int ret = 0;
+
+	BUG_ON(!timer->function);
+
+	/*
+	 * This is a common optimization triggered by the networking code - if
+	 * the timer is re-modified to have the same timeout or ends up in the
+	 * same array bucket then just return:
+	 */
+	if (!(options & MOD_TIMER_NOTPENDING) && timer_pending(timer)) {
+		/*
+		 * The downside of this optimization is that it can result in
+		 * larger granularity than you would get from adding a new
+		 * timer with this expiry.
+		 */
+		long diff = timer->expires - expires;
+
+		if (!diff)
+			return 1;
+		if (options & MOD_TIMER_REDUCE && diff <= 0)
+			return 1;
+
+		/*
+		 * We lock timer base and calculate the bucket index right
+		 * here. If the timer ends up in the same bucket, then we
+		 * just update the expiry time and avoid the whole
+		 * dequeue/enqueue dance.
+		 */
+		base = lock_timer_base(timer, &flags);
+		forward_timer_base(base);
+
+		if (timer_pending(timer) && (options & MOD_TIMER_REDUCE) &&
+		    time_before_eq(timer->expires, expires)) {
+			ret = 1;
+			goto out_unlock;
+		}
+
+		clk = base->clk;
+		idx = calc_wheel_index(expires, clk, &bucket_expiry);
+
+		/*
+		 * Retrieve and compare the array index of the pending
+		 * timer. If it matches set the expiry to the new value so a
+		 * subsequent call will exit in the expires check above.
+		 */
+		if (idx == timer_get_idx(timer)) {
+			if (!(options & MOD_TIMER_REDUCE))
+				timer->expires = expires;
+			else if (time_after(timer->expires, expires))
+				timer->expires = expires;
+			ret = 1;
+			goto out_unlock;
+		}
+	} else {
+		base = lock_timer_base(timer, &flags);
+		forward_timer_base(base);
+	}
+
+	ret = detach_if_pending(timer, base, false);
+	if (!ret && (options & MOD_TIMER_PENDING_ONLY))
+		goto out_unlock;
+
+	new_base = get_target_base(base, timer->flags);
+
+	if (base != new_base) {
+		/*
+		 * We are trying to schedule the timer on the new base.
+		 * However we can't change timer's base while it is running,
+		 * otherwise del_timer_sync() can't detect that the timer's
+		 * handler yet has not finished. This also guarantees that the
+		 * timer is serialized wrt itself.
+		 */
+		if (likely(base->running_timer != timer)) {
+			/* See the comment in lock_timer_base() */
+			timer->flags |= TIMER_MIGRATING;
+
+			raw_spin_unlock(&base->lock);
+			base = new_base;
+			raw_spin_lock(&base->lock);
+			WRITE_ONCE(timer->flags,
+				   (timer->flags & ~TIMER_BASEMASK) | base->cpu);
+			forward_timer_base(base);
+		}
+	}
+
+	debug_timer_activate(timer);
+
+	timer->expires = expires;
+	/*
+	 * If 'idx' was calculated above and the base time did not advance
+	 * between calculating 'idx' and possibly switching the base, only
+	 * enqueue_timer() is required. Otherwise we need to (re)calculate
+	 * the wheel index via internal_add_timer().
+	 */
+	if (idx != UINT_MAX && clk == base->clk)
+		enqueue_timer(base, timer, idx, bucket_expiry);
+	else
+		internal_add_timer(base, timer);
+
+out_unlock:
+	raw_spin_unlock_irqrestore(&base->lock, flags);
+
+	return ret;
+}
+
+/**
+ * mod_timer_pending - modify a pending timer's timeout
+ * @timer: the pending timer to be modified
+ * @expires: new timeout in jiffies
+ *
+ * mod_timer_pending() is the same for pending timers as mod_timer(),
+ * but will not re-activate and modify already deleted timers.
+ *
+ * It is useful for unserialized use of timers.
+ */
+int mod_timer_pending(struct timer_list *timer, unsigned long expires)
+{
+	return __mod_timer(timer, expires, MOD_TIMER_PENDING_ONLY);
+}
+EXPORT_SYMBOL(mod_timer_pending);
+
+/**
+ * mod_timer - modify a timer's timeout
+ * @timer: the timer to be modified
+ * @expires: new timeout in jiffies
+ *
+ * mod_timer() is a more efficient way to update the expire field of an
+ * active timer (if the timer is inactive it will be activated)
+ *
+ * mod_timer(timer, expires) is equivalent to:
+ *
+ *     del_timer(timer); timer->expires = expires; add_timer(timer);
+ *
+ * Note that if there are multiple unserialized concurrent users of the
+ * same timer, then mod_timer() is the only safe way to modify the timeout,
+ * since add_timer() cannot modify an already running timer.
+ *
+ * The function returns whether it has modified a pending timer or not.
+ * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an
+ * active timer returns 1.)
+ */
+int mod_timer(struct timer_list *timer, unsigned long expires)
+{
+	return __mod_timer(timer, expires, 0);
+}
+EXPORT_SYMBOL(mod_timer);
+
+/**
+ * timer_reduce - Modify a timer's timeout if it would reduce the timeout
+ * @timer:	The timer to be modified
+ * @expires:	New timeout in jiffies
+ *
+ * timer_reduce() is very similar to mod_timer(), except that it will only
+ * modify a running timer if that would reduce the expiration time (it will
+ * start a timer that isn't running).
+ */
+int timer_reduce(struct timer_list *timer, unsigned long expires)
+{
+	return __mod_timer(timer, expires, MOD_TIMER_REDUCE);
+}
+EXPORT_SYMBOL(timer_reduce);
+
+/**
+ * add_timer - start a timer
+ * @timer: the timer to be added
+ *
+ * The kernel will do a ->function(@timer) callback from the
+ * timer interrupt at the ->expires point in the future. The
+ * current time is 'jiffies'.
+ *
+ * The timer's ->expires, ->function fields must be set prior calling this
+ * function.
+ *
+ * Timers with an ->expires field in the past will be executed in the next
+ * timer tick.
+ */
+void add_timer(struct timer_list *timer)
+{
+	BUG_ON(timer_pending(timer));
+	__mod_timer(timer, timer->expires, MOD_TIMER_NOTPENDING);
+}
+EXPORT_SYMBOL(add_timer);
+
+/**
+ * add_timer_on - start a timer on a particular CPU
+ * @timer: the timer to be added
+ * @cpu: the CPU to start it on
+ *
+ * This is not very scalable on SMP. Double adds are not possible.
+ */
+void add_timer_on(struct timer_list *timer, int cpu)
+{
+	struct timer_base *new_base, *base;
+	unsigned long flags;
+
+	BUG_ON(timer_pending(timer) || !timer->function);
+
+	new_base = get_timer_cpu_base(timer->flags, cpu);
+
+	/*
+	 * If @timer was on a different CPU, it should be migrated with the
+	 * old base locked to prevent other operations proceeding with the
+	 * wrong base locked.  See lock_timer_base().
+	 */
+	base = lock_timer_base(timer, &flags);
+	if (base != new_base) {
+		timer->flags |= TIMER_MIGRATING;
+
+		raw_spin_unlock(&base->lock);
+		base = new_base;
+		raw_spin_lock(&base->lock);
+		WRITE_ONCE(timer->flags,
+			   (timer->flags & ~TIMER_BASEMASK) | cpu);
+	}
+	forward_timer_base(base);
+
+	debug_timer_activate(timer);
+	internal_add_timer(base, timer);
+	raw_spin_unlock_irqrestore(&base->lock, flags);
+}
+EXPORT_SYMBOL_GPL(add_timer_on);
+
+/**
+ * del_timer - deactivate a timer.
+ * @timer: the timer to be deactivated
+ *
+ * del_timer() deactivates a timer - this works on both active and inactive
+ * timers.
+ *
+ * The function returns whether it has deactivated a pending timer or not.
+ * (ie. del_timer() of an inactive timer returns 0, del_timer() of an
+ * active timer returns 1.)
+ */
+int del_timer(struct timer_list *timer)
+{
+	struct timer_base *base;
+	unsigned long flags;
+	int ret = 0;
+
+	debug_assert_init(timer);
+
+	if (timer_pending(timer)) {
+		base = lock_timer_base(timer, &flags);
+		ret = detach_if_pending(timer, base, true);
+		raw_spin_unlock_irqrestore(&base->lock, flags);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(del_timer);
+
+/**
+ * try_to_del_timer_sync - Try to deactivate a timer
+ * @timer: timer to delete
+ *
+ * This function tries to deactivate a timer. Upon successful (ret >= 0)
+ * exit the timer is not queued and the handler is not running on any CPU.
+ */
+int try_to_del_timer_sync(struct timer_list *timer)
+{
+	struct timer_base *base;
+	unsigned long flags;
+	int ret = -1;
+
+	debug_assert_init(timer);
+
+	base = lock_timer_base(timer, &flags);
+
+	if (base->running_timer != timer)
+		ret = detach_if_pending(timer, base, true);
+
+	raw_spin_unlock_irqrestore(&base->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(try_to_del_timer_sync);
+
+#ifdef CONFIG_PREEMPT_RT
+static __init void timer_base_init_expiry_lock(struct timer_base *base)
+{
+	spin_lock_init(&base->expiry_lock);
+}
+
+static inline void timer_base_lock_expiry(struct timer_base *base)
+{
+	spin_lock(&base->expiry_lock);
+}
+
+static inline void timer_base_unlock_expiry(struct timer_base *base)
+{
+	spin_unlock(&base->expiry_lock);
+}
+
+/*
+ * The counterpart to del_timer_wait_running().
+ *
+ * If there is a waiter for base->expiry_lock, then it was waiting for the
+ * timer callback to finish. Drop expiry_lock and reacquire it. That allows
+ * the waiter to acquire the lock and make progress.
+ */
+static void timer_sync_wait_running(struct timer_base *base)
+{
+	if (atomic_read(&base->timer_waiters)) {
+		raw_spin_unlock_irq(&base->lock);
+		spin_unlock(&base->expiry_lock);
+		spin_lock(&base->expiry_lock);
+		raw_spin_lock_irq(&base->lock);
+	}
+}
+
+/*
+ * This function is called on PREEMPT_RT kernels when the fast path
+ * deletion of a timer failed because the timer callback function was
+ * running.
+ *
+ * This prevents priority inversion, if the softirq thread on a remote CPU
+ * got preempted, and it prevents a life lock when the task which tries to
+ * delete a timer preempted the softirq thread running the timer callback
+ * function.
+ */
+static void del_timer_wait_running(struct timer_list *timer)
+{
+	u32 tf;
+
+	tf = READ_ONCE(timer->flags);
+	if (!(tf & (TIMER_MIGRATING | TIMER_IRQSAFE))) {
+		struct timer_base *base = get_timer_base(tf);
+
+		/*
+		 * Mark the base as contended and grab the expiry lock,
+		 * which is held by the softirq across the timer
+		 * callback. Drop the lock immediately so the softirq can
+		 * expire the next timer. In theory the timer could already
+		 * be running again, but that's more than unlikely and just
+		 * causes another wait loop.
+		 */
+		atomic_inc(&base->timer_waiters);
+		spin_lock_bh(&base->expiry_lock);
+		atomic_dec(&base->timer_waiters);
+		spin_unlock_bh(&base->expiry_lock);
+	}
+}
+#else
+static inline void timer_base_init_expiry_lock(struct timer_base *base) { }
+static inline void timer_base_lock_expiry(struct timer_base *base) { }
+static inline void timer_base_unlock_expiry(struct timer_base *base) { }
+static inline void timer_sync_wait_running(struct timer_base *base) { }
+static inline void del_timer_wait_running(struct timer_list *timer) { }
+#endif
+
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
+/**
+ * del_timer_sync - deactivate a timer and wait for the handler to finish.
+ * @timer: the timer to be deactivated
+ *
+ * This function only differs from del_timer() on SMP: besides deactivating
+ * the timer it also makes sure the handler has finished executing on other
+ * CPUs.
+ *
+ * Synchronization rules: Callers must prevent restarting of the timer,
+ * otherwise this function is meaningless. It must not be called from
+ * interrupt contexts unless the timer is an irqsafe one. The caller must
+ * not hold locks which would prevent completion of the timer's
+ * handler. The timer's handler must not call add_timer_on(). Upon exit the
+ * timer is not queued and the handler is not running on any CPU.
+ *
+ * Note: For !irqsafe timers, you must not hold locks that are held in
+ *   interrupt context while calling this function. Even if the lock has
+ *   nothing to do with the timer in question.  Here's why::
+ *
+ *    CPU0                             CPU1
+ *    ----                             ----
+ *                                     <SOFTIRQ>
+ *                                       call_timer_fn();
+ *                                       base->running_timer = mytimer;
+ *    spin_lock_irq(somelock);
+ *                                     <IRQ>
+ *                                        spin_lock(somelock);
+ *    del_timer_sync(mytimer);
+ *    while (base->running_timer == mytimer);
+ *
+ * Now del_timer_sync() will never return and never release somelock.
+ * The interrupt on the other CPU is waiting to grab somelock but
+ * it has interrupted the softirq that CPU0 is waiting to finish.
+ *
+ * The function returns whether it has deactivated a pending timer or not.
+ */
+int del_timer_sync(struct timer_list *timer)
+{
+	int ret;
+
+#ifdef CONFIG_LOCKDEP
+	unsigned long flags;
+
+	/*
+	 * If lockdep gives a backtrace here, please reference
+	 * the synchronization rules above.
+	 */
+	local_irq_save(flags);
+	lock_map_acquire(&timer->lockdep_map);
+	lock_map_release(&timer->lockdep_map);
+	local_irq_restore(flags);
+#endif
+	/*
+	 * don't use it in hardirq context, because it
+	 * could lead to deadlock.
+	 */
+	WARN_ON(in_irq() && !(timer->flags & TIMER_IRQSAFE));
+
+	/*
+	 * Must be able to sleep on PREEMPT_RT because of the slowpath in
+	 * del_timer_wait_running().
+	 */
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && !(timer->flags & TIMER_IRQSAFE))
+		lockdep_assert_preemption_enabled();
+
+	do {
+		ret = try_to_del_timer_sync(timer);
+
+		if (unlikely(ret < 0)) {
+			del_timer_wait_running(timer);
+			cpu_relax();
+		}
+	} while (ret < 0);
+
+	return ret;
+}
+EXPORT_SYMBOL(del_timer_sync);
+#endif
+
+static void call_timer_fn(struct timer_list *timer,
+			  void (*fn)(struct timer_list *),
+			  unsigned long baseclk)
+{
+	int count = preempt_count();
+
+#ifdef CONFIG_LOCKDEP
+	/*
+	 * It is permissible to free the timer from inside the
+	 * function that is called from it, this we need to take into
+	 * account for lockdep too. To avoid bogus "held lock freed"
+	 * warnings as well as problems when looking into
+	 * timer->lockdep_map, make a copy and use that here.
+	 */
+	struct lockdep_map lockdep_map;
+
+	lockdep_copy_map(&lockdep_map, &timer->lockdep_map);
+#endif
+	/*
+	 * Couple the lock chain with the lock chain at
+	 * del_timer_sync() by acquiring the lock_map around the fn()
+	 * call here and in del_timer_sync().
+	 */
+	lock_map_acquire(&lockdep_map);
+
+	trace_timer_expire_entry(timer, baseclk);
+	fn(timer);
+	trace_timer_expire_exit(timer);
+
+	lock_map_release(&lockdep_map);
+
+	if (count != preempt_count()) {
+		WARN_ONCE(1, "timer: %pS preempt leak: %08x -> %08x\n",
+			  fn, count, preempt_count());
+		/*
+		 * Restore the preempt count. That gives us a decent
+		 * chance to survive and extract information. If the
+		 * callback kept a lock held, bad luck, but not worse
+		 * than the BUG() we had.
+		 */
+		preempt_count_set(count);
+	}
+}
+
+static void expire_timers(struct timer_base *base, struct hlist_head *head)
+{
+	/*
+	 * This value is required only for tracing. base->clk was
+	 * incremented directly before expire_timers was called. But expiry
+	 * is related to the old base->clk value.
+	 */
+	unsigned long baseclk = base->clk - 1;
+
+	while (!hlist_empty(head)) {
+		struct timer_list *timer;
+		void (*fn)(struct timer_list *);
+
+		timer = hlist_entry(head->first, struct timer_list, entry);
+
+		base->running_timer = timer;
+		detach_timer(timer, true);
+
+		fn = timer->function;
+
+		if (timer->flags & TIMER_IRQSAFE) {
+			raw_spin_unlock(&base->lock);
+			call_timer_fn(timer, fn, baseclk);
+			raw_spin_lock(&base->lock);
+			base->running_timer = NULL;
+		} else {
+			raw_spin_unlock_irq(&base->lock);
+			call_timer_fn(timer, fn, baseclk);
+			raw_spin_lock_irq(&base->lock);
+			base->running_timer = NULL;
+			timer_sync_wait_running(base);
+		}
+	}
+}
+
+static int collect_expired_timers(struct timer_base *base,
+				  struct hlist_head *heads)
+{
+	unsigned long clk = base->clk = base->next_expiry;
+	struct hlist_head *vec;
+	int i, levels = 0;
+	unsigned int idx;
+
+	for (i = 0; i < LVL_DEPTH; i++) {
+		idx = (clk & LVL_MASK) + i * LVL_SIZE;
+
+		if (__test_and_clear_bit(idx, base->pending_map)) {
+			vec = base->vectors + idx;
+			hlist_move_list(vec, heads++);
+			levels++;
+		}
+		/* Is it time to look at the next level? */
+		if (clk & LVL_CLK_MASK)
+			break;
+		/* Shift clock for the next level granularity */
+		clk >>= LVL_CLK_SHIFT;
+	}
+	return levels;
+}
+
+/*
+ * Find the next pending bucket of a level. Search from level start (@offset)
+ * + @clk upwards and if nothing there, search from start of the level
+ * (@offset) up to @offset + clk.
+ */
+static int next_pending_bucket(struct timer_base *base, unsigned offset,
+			       unsigned clk)
+{
+	unsigned pos, start = offset + clk;
+	unsigned end = offset + LVL_SIZE;
+
+	pos = find_next_bit(base->pending_map, end, start);
+	if (pos < end)
+		return pos - start;
+
+	pos = find_next_bit(base->pending_map, start, offset);
+	return pos < start ? pos + LVL_SIZE - start : -1;
+}
+
+/*
+ * Search the first expiring timer in the various clock levels. Caller must
+ * hold base->lock.
+ */
+static unsigned long __next_timer_interrupt(struct timer_base *base)
+{
+	unsigned long clk, next, adj;
+	unsigned lvl, offset = 0;
+
+	next = base->clk + NEXT_TIMER_MAX_DELTA;
+	clk = base->clk;
+	for (lvl = 0; lvl < LVL_DEPTH; lvl++, offset += LVL_SIZE) {
+		int pos = next_pending_bucket(base, offset, clk & LVL_MASK);
+		unsigned long lvl_clk = clk & LVL_CLK_MASK;
+
+		if (pos >= 0) {
+			unsigned long tmp = clk + (unsigned long) pos;
+
+			tmp <<= LVL_SHIFT(lvl);
+			if (time_before(tmp, next))
+				next = tmp;
+
+			/*
+			 * If the next expiration happens before we reach
+			 * the next level, no need to check further.
+			 */
+			if (pos <= ((LVL_CLK_DIV - lvl_clk) & LVL_CLK_MASK))
+				break;
+		}
+		/*
+		 * Clock for the next level. If the current level clock lower
+		 * bits are zero, we look at the next level as is. If not we
+		 * need to advance it by one because that's going to be the
+		 * next expiring bucket in that level. base->clk is the next
+		 * expiring jiffie. So in case of:
+		 *
+		 * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0
+		 *  0    0    0    0    0    0
+		 *
+		 * we have to look at all levels @index 0. With
+		 *
+		 * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0
+		 *  0    0    0    0    0    2
+		 *
+		 * LVL0 has the next expiring bucket @index 2. The upper
+		 * levels have the next expiring bucket @index 1.
+		 *
+		 * In case that the propagation wraps the next level the same
+		 * rules apply:
+		 *
+		 * LVL5 LVL4 LVL3 LVL2 LVL1 LVL0
+		 *  0    0    0    0    F    2
+		 *
+		 * So after looking at LVL0 we get:
+		 *
+		 * LVL5 LVL4 LVL3 LVL2 LVL1
+		 *  0    0    0    1    0
+		 *
+		 * So no propagation from LVL1 to LVL2 because that happened
+		 * with the add already, but then we need to propagate further
+		 * from LVL2 to LVL3.
+		 *
+		 * So the simple check whether the lower bits of the current
+		 * level are 0 or not is sufficient for all cases.
+		 */
+		adj = lvl_clk ? 1 : 0;
+		clk >>= LVL_CLK_SHIFT;
+		clk += adj;
+	}
+
+	base->next_expiry_recalc = false;
+	base->timers_pending = !(next == base->clk + NEXT_TIMER_MAX_DELTA);
+
+	return next;
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+/*
+ * Check, if the next hrtimer event is before the next timer wheel
+ * event:
+ */
+static u64 cmp_next_hrtimer_event(u64 basem, u64 expires)
+{
+	u64 nextevt = hrtimer_get_next_event();
+
+	/*
+	 * If high resolution timers are enabled
+	 * hrtimer_get_next_event() returns KTIME_MAX.
+	 */
+	if (expires <= nextevt)
+		return expires;
+
+	/*
+	 * If the next timer is already expired, return the tick base
+	 * time so the tick is fired immediately.
+	 */
+	if (nextevt <= basem)
+		return basem;
+
+	/*
+	 * Round up to the next jiffie. High resolution timers are
+	 * off, so the hrtimers are expired in the tick and we need to
+	 * make sure that this tick really expires the timer to avoid
+	 * a ping pong of the nohz stop code.
+	 *
+	 * Use DIV_ROUND_UP_ULL to prevent gcc calling __divdi3
+	 */
+	return DIV_ROUND_UP_ULL(nextevt, TICK_NSEC) * TICK_NSEC;
+}
+
+/**
+ * get_next_timer_interrupt - return the time (clock mono) of the next timer
+ * @basej:	base time jiffies
+ * @basem:	base time clock monotonic
+ *
+ * Returns the tick aligned clock monotonic time of the next pending
+ * timer or KTIME_MAX if no timer is pending.
+ */
+u64 get_next_timer_interrupt(unsigned long basej, u64 basem)
+{
+	struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+	u64 expires = KTIME_MAX;
+	unsigned long nextevt;
+
+	/*
+	 * Pretend that there is no timer pending if the cpu is offline.
+	 * Possible pending timers will be migrated later to an active cpu.
+	 */
+	if (cpu_is_offline(smp_processor_id()))
+		return expires;
+
+	raw_spin_lock(&base->lock);
+	if (base->next_expiry_recalc)
+		base->next_expiry = __next_timer_interrupt(base);
+	nextevt = base->next_expiry;
+
+	/*
+	 * We have a fresh next event. Check whether we can forward the
+	 * base. We can only do that when @basej is past base->clk
+	 * otherwise we might rewind base->clk.
+	 */
+	if (time_after(basej, base->clk)) {
+		if (time_after(nextevt, basej))
+			base->clk = basej;
+		else if (time_after(nextevt, base->clk))
+			base->clk = nextevt;
+	}
+
+	if (time_before_eq(nextevt, basej)) {
+		expires = basem;
+		base->is_idle = false;
+	} else {
+		if (base->timers_pending)
+			expires = basem + (u64)(nextevt - basej) * TICK_NSEC;
+		/*
+		 * If we expect to sleep more than a tick, mark the base idle.
+		 * Also the tick is stopped so any added timer must forward
+		 * the base clk itself to keep granularity small. This idle
+		 * logic is only maintained for the BASE_STD base, deferrable
+		 * timers may still see large granularity skew (by design).
+		 */
+		if ((expires - basem) > TICK_NSEC)
+			base->is_idle = true;
+	}
+	raw_spin_unlock(&base->lock);
+
+	return cmp_next_hrtimer_event(basem, expires);
+}
+
+/**
+ * timer_clear_idle - Clear the idle state of the timer base
+ *
+ * Called with interrupts disabled
+ */
+void timer_clear_idle(void)
+{
+	struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+
+	/*
+	 * We do this unlocked. The worst outcome is a remote enqueue sending
+	 * a pointless IPI, but taking the lock would just make the window for
+	 * sending the IPI a few instructions smaller for the cost of taking
+	 * the lock in the exit from idle path.
+	 */
+	base->is_idle = false;
+}
+#endif
+
+/**
+ * __run_timers - run all expired timers (if any) on this CPU.
+ * @base: the timer vector to be processed.
+ */
+static inline void __run_timers(struct timer_base *base)
+{
+	struct hlist_head heads[LVL_DEPTH];
+	int levels;
+
+	if (time_before(jiffies, base->next_expiry))
+		return;
+
+	timer_base_lock_expiry(base);
+	raw_spin_lock_irq(&base->lock);
+
+	while (time_after_eq(jiffies, base->clk) &&
+	       time_after_eq(jiffies, base->next_expiry)) {
+		levels = collect_expired_timers(base, heads);
+		/*
+		 * The two possible reasons for not finding any expired
+		 * timer at this clk are that all matching timers have been
+		 * dequeued or no timer has been queued since
+		 * base::next_expiry was set to base::clk +
+		 * NEXT_TIMER_MAX_DELTA.
+		 */
+		WARN_ON_ONCE(!levels && !base->next_expiry_recalc
+			     && base->timers_pending);
+		base->clk++;
+		base->next_expiry = __next_timer_interrupt(base);
+
+		while (levels--)
+			expire_timers(base, heads + levels);
+	}
+	raw_spin_unlock_irq(&base->lock);
+	timer_base_unlock_expiry(base);
+}
+
+/*
+ * This function runs timers and the timer-tq in bottom half context.
+ */
+static __latent_entropy void run_timer_softirq(struct softirq_action *h)
+{
+	struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+
+	__run_timers(base);
+	if (IS_ENABLED(CONFIG_NO_HZ_COMMON))
+		__run_timers(this_cpu_ptr(&timer_bases[BASE_DEF]));
+}
+
+/*
+ * Called by the local, per-CPU timer interrupt on SMP.
+ */
+static void run_local_timers(void)
+{
+	struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+
+	hrtimer_run_queues();
+	/* Raise the softirq only if required. */
+	if (time_before(jiffies, base->next_expiry)) {
+		if (!IS_ENABLED(CONFIG_NO_HZ_COMMON))
+			return;
+		/* CPU is awake, so check the deferrable base. */
+		base++;
+		if (time_before(jiffies, base->next_expiry))
+			return;
+	}
+	raise_softirq(TIMER_SOFTIRQ);
+}
+
+/*
+ * Called from the timer interrupt handler to charge one tick to the current
+ * process.  user_tick is 1 if the tick is user time, 0 for system.
+ */
+void update_process_times(int user_tick)
+{
+	struct task_struct *p = current;
+
+	/* Note: this timer irq context must be accounted for as well. */
+	account_process_tick(p, user_tick);
+	run_local_timers();
+	rcu_sched_clock_irq(user_tick);
+#ifdef CONFIG_IRQ_WORK
+	if (in_irq())
+		irq_work_tick();
+#endif
+	scheduler_tick();
+	if (IS_ENABLED(CONFIG_POSIX_TIMERS))
+		run_posix_cpu_timers();
+}
+
+/*
+ * Since schedule_timeout()'s timer is defined on the stack, it must store
+ * the target task on the stack as well.
+ */
+struct process_timer {
+	struct timer_list timer;
+	struct task_struct *task;
+};
+
+static void process_timeout(struct timer_list *t)
+{
+	struct process_timer *timeout = from_timer(timeout, t, timer);
+
+	wake_up_process(timeout->task);
+}
+
+/**
+ * schedule_timeout - sleep until timeout
+ * @timeout: timeout value in jiffies
+ *
+ * Make the current task sleep until @timeout jiffies have elapsed.
+ * The function behavior depends on the current task state
+ * (see also set_current_state() description):
+ *
+ * %TASK_RUNNING - the scheduler is called, but the task does not sleep
+ * at all. That happens because sched_submit_work() does nothing for
+ * tasks in %TASK_RUNNING state.
+ *
+ * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to
+ * pass before the routine returns unless the current task is explicitly
+ * woken up, (e.g. by wake_up_process()).
+ *
+ * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
+ * delivered to the current task or the current task is explicitly woken
+ * up.
+ *
+ * The current task state is guaranteed to be %TASK_RUNNING when this
+ * routine returns.
+ *
+ * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule
+ * the CPU away without a bound on the timeout. In this case the return
+ * value will be %MAX_SCHEDULE_TIMEOUT.
+ *
+ * Returns 0 when the timer has expired otherwise the remaining time in
+ * jiffies will be returned. In all cases the return value is guaranteed
+ * to be non-negative.
+ */
+signed long __sched schedule_timeout(signed long timeout)
+{
+	struct process_timer timer;
+	unsigned long expire;
+
+	switch (timeout)
+	{
+	case MAX_SCHEDULE_TIMEOUT:
+		/*
+		 * These two special cases are useful to be comfortable
+		 * in the caller. Nothing more. We could take
+		 * MAX_SCHEDULE_TIMEOUT from one of the negative value
+		 * but I' d like to return a valid offset (>=0) to allow
+		 * the caller to do everything it want with the retval.
+		 */
+		schedule();
+		goto out;
+	default:
+		/*
+		 * Another bit of PARANOID. Note that the retval will be
+		 * 0 since no piece of kernel is supposed to do a check
+		 * for a negative retval of schedule_timeout() (since it
+		 * should never happens anyway). You just have the printk()
+		 * that will tell you if something is gone wrong and where.
+		 */
+		if (timeout < 0) {
+			printk(KERN_ERR "schedule_timeout: wrong timeout "
+				"value %lx\n", timeout);
+			dump_stack();
+			__set_current_state(TASK_RUNNING);
+			goto out;
+		}
+	}
+
+	expire = timeout + jiffies;
+
+	timer.task = current;
+	timer_setup_on_stack(&timer.timer, process_timeout, 0);
+	__mod_timer(&timer.timer, expire, MOD_TIMER_NOTPENDING);
+	schedule();
+	del_singleshot_timer_sync(&timer.timer);
+
+	/* Remove the timer from the object tracker */
+	destroy_timer_on_stack(&timer.timer);
+
+	timeout = expire - jiffies;
+
+ out:
+	return timeout < 0 ? 0 : timeout;
+}
+EXPORT_SYMBOL(schedule_timeout);
+
+/*
+ * We can use __set_current_state() here because schedule_timeout() calls
+ * schedule() unconditionally.
+ */
+signed long __sched schedule_timeout_interruptible(signed long timeout)
+{
+	__set_current_state(TASK_INTERRUPTIBLE);
+	return schedule_timeout(timeout);
+}
+EXPORT_SYMBOL(schedule_timeout_interruptible);
+
+signed long __sched schedule_timeout_killable(signed long timeout)
+{
+	__set_current_state(TASK_KILLABLE);
+	return schedule_timeout(timeout);
+}
+EXPORT_SYMBOL(schedule_timeout_killable);
+
+signed long __sched schedule_timeout_uninterruptible(signed long timeout)
+{
+	__set_current_state(TASK_UNINTERRUPTIBLE);
+	return schedule_timeout(timeout);
+}
+EXPORT_SYMBOL(schedule_timeout_uninterruptible);
+
+/*
+ * Like schedule_timeout_uninterruptible(), except this task will not contribute
+ * to load average.
+ */
+signed long __sched schedule_timeout_idle(signed long timeout)
+{
+	__set_current_state(TASK_IDLE);
+	return schedule_timeout(timeout);
+}
+EXPORT_SYMBOL(schedule_timeout_idle);
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void migrate_timer_list(struct timer_base *new_base, struct hlist_head *head)
+{
+	struct timer_list *timer;
+	int cpu = new_base->cpu;
+
+	while (!hlist_empty(head)) {
+		timer = hlist_entry(head->first, struct timer_list, entry);
+		detach_timer(timer, false);
+		timer->flags = (timer->flags & ~TIMER_BASEMASK) | cpu;
+		internal_add_timer(new_base, timer);
+	}
+}
+
+int timers_prepare_cpu(unsigned int cpu)
+{
+	struct timer_base *base;
+	int b;
+
+	for (b = 0; b < NR_BASES; b++) {
+		base = per_cpu_ptr(&timer_bases[b], cpu);
+		base->clk = jiffies;
+		base->next_expiry = base->clk + NEXT_TIMER_MAX_DELTA;
+		base->next_expiry_recalc = false;
+		base->timers_pending = false;
+		base->is_idle = false;
+	}
+	return 0;
+}
+
+int timers_dead_cpu(unsigned int cpu)
+{
+	struct timer_base *old_base;
+	struct timer_base *new_base;
+	int b, i;
+
+	BUG_ON(cpu_online(cpu));
+
+	for (b = 0; b < NR_BASES; b++) {
+		old_base = per_cpu_ptr(&timer_bases[b], cpu);
+		new_base = get_cpu_ptr(&timer_bases[b]);
+		/*
+		 * The caller is globally serialized and nobody else
+		 * takes two locks at once, deadlock is not possible.
+		 */
+		raw_spin_lock_irq(&new_base->lock);
+		raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
+
+		/*
+		 * The current CPUs base clock might be stale. Update it
+		 * before moving the timers over.
+		 */
+		forward_timer_base(new_base);
+
+		BUG_ON(old_base->running_timer);
+
+		for (i = 0; i < WHEEL_SIZE; i++)
+			migrate_timer_list(new_base, old_base->vectors + i);
+
+		raw_spin_unlock(&old_base->lock);
+		raw_spin_unlock_irq(&new_base->lock);
+		put_cpu_ptr(&timer_bases);
+	}
+	return 0;
+}
+
+#endif /* CONFIG_HOTPLUG_CPU */
+
+static void __init init_timer_cpu(int cpu)
+{
+	struct timer_base *base;
+	int i;
+
+	for (i = 0; i < NR_BASES; i++) {
+		base = per_cpu_ptr(&timer_bases[i], cpu);
+		base->cpu = cpu;
+		raw_spin_lock_init(&base->lock);
+		base->clk = jiffies;
+		base->next_expiry = base->clk + NEXT_TIMER_MAX_DELTA;
+		timer_base_init_expiry_lock(base);
+	}
+}
+
+static void __init init_timer_cpus(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		init_timer_cpu(cpu);
+}
+
+void __init init_timers(void)
+{
+	init_timer_cpus();
+	posix_cputimers_init_work();
+	open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
+}
+
+/**
+ * msleep - sleep safely even with waitqueue interruptions
+ * @msecs: Time in milliseconds to sleep for
+ */
+void msleep(unsigned int msecs)
+{
+	unsigned long timeout = msecs_to_jiffies(msecs) + 1;
+
+	while (timeout)
+		timeout = schedule_timeout_uninterruptible(timeout);
+}
+
+EXPORT_SYMBOL(msleep);
+
+/**
+ * msleep_interruptible - sleep waiting for signals
+ * @msecs: Time in milliseconds to sleep for
+ */
+unsigned long msleep_interruptible(unsigned int msecs)
+{
+	unsigned long timeout = msecs_to_jiffies(msecs) + 1;
+
+	while (timeout && !signal_pending(current))
+		timeout = schedule_timeout_interruptible(timeout);
+	return jiffies_to_msecs(timeout);
+}
+
+EXPORT_SYMBOL(msleep_interruptible);
+
+/**
+ * usleep_range_state - Sleep for an approximate time in a given state
+ * @min:	Minimum time in usecs to sleep
+ * @max:	Maximum time in usecs to sleep
+ * @state:	State of the current task that will be while sleeping
+ *
+ * In non-atomic context where the exact wakeup time is flexible, use
+ * usleep_range_state() instead of udelay().  The sleep improves responsiveness
+ * by avoiding the CPU-hogging busy-wait of udelay(), and the range reduces
+ * power usage by allowing hrtimers to take advantage of an already-
+ * scheduled interrupt instead of scheduling a new one just for this sleep.
+ */
+void __sched usleep_range_state(unsigned long min, unsigned long max,
+				unsigned int state)
+{
+	ktime_t exp = ktime_add_us(ktime_get(), min);
+	u64 delta = (u64)(max - min) * NSEC_PER_USEC;
+
+	for (;;) {
+		__set_current_state(state);
+		/* Do not return before the requested sleep time has elapsed */
+		if (!schedule_hrtimeout_range(&exp, delta, HRTIMER_MODE_ABS))
+			break;
+	}
+}
+EXPORT_SYMBOL(usleep_range_state);
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
new file mode 100644
index 000000000..ed7d6ad69
--- /dev/null
+++ b/kernel/time/timer_list.c
@@ -0,0 +1,360 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * List pending timers
+ *
+ * Copyright(C) 2006, Red Hat, Inc., Ingo Molnar
+ */
+
+#include <linux/proc_fs.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/kallsyms.h>
+#include <linux/nmi.h>
+
+#include <linux/uaccess.h>
+
+#include "tick-internal.h"
+
+struct timer_list_iter {
+	int cpu;
+	bool second_pass;
+	u64 now;
+};
+
+/*
+ * This allows printing both to /proc/timer_list and
+ * to the console (on SysRq-Q):
+ */
+__printf(2, 3)
+static void SEQ_printf(struct seq_file *m, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+
+	if (m)
+		seq_vprintf(m, fmt, args);
+	else
+		vprintk(fmt, args);
+
+	va_end(args);
+}
+
+static void
+print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
+	    int idx, u64 now)
+{
+	SEQ_printf(m, " #%d: <%pK>, %ps", idx, taddr, timer->function);
+	SEQ_printf(m, ", S:%02x", timer->state);
+	SEQ_printf(m, "\n");
+	SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
+		(unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
+		(unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
+		(long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
+		(long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
+}
+
+static void
+print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
+		    u64 now)
+{
+	struct hrtimer *timer, tmp;
+	unsigned long next = 0, i;
+	struct timerqueue_node *curr;
+	unsigned long flags;
+
+next_one:
+	i = 0;
+
+	touch_nmi_watchdog();
+
+	raw_spin_lock_irqsave(&base->cpu_base->lock, flags);
+
+	curr = timerqueue_getnext(&base->active);
+	/*
+	 * Crude but we have to do this O(N*N) thing, because
+	 * we have to unlock the base when printing:
+	 */
+	while (curr && i < next) {
+		curr = timerqueue_iterate_next(curr);
+		i++;
+	}
+
+	if (curr) {
+
+		timer = container_of(curr, struct hrtimer, node);
+		tmp = *timer;
+		raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
+
+		print_timer(m, timer, &tmp, i, now);
+		next++;
+		goto next_one;
+	}
+	raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
+}
+
+static void
+print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
+{
+	SEQ_printf(m, "  .base:       %pK\n", base);
+	SEQ_printf(m, "  .index:      %d\n", base->index);
+
+	SEQ_printf(m, "  .resolution: %u nsecs\n", hrtimer_resolution);
+
+	SEQ_printf(m,   "  .get_time:   %ps\n", base->get_time);
+#ifdef CONFIG_HIGH_RES_TIMERS
+	SEQ_printf(m, "  .offset:     %Lu nsecs\n",
+		   (unsigned long long) ktime_to_ns(base->offset));
+#endif
+	SEQ_printf(m,   "active timers:\n");
+	print_active_timers(m, base, now + ktime_to_ns(base->offset));
+}
+
+static void print_cpu(struct seq_file *m, int cpu, u64 now)
+{
+	struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
+	int i;
+
+	SEQ_printf(m, "cpu: %d\n", cpu);
+	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
+		SEQ_printf(m, " clock %d:\n", i);
+		print_base(m, cpu_base->clock_base + i, now);
+	}
+#define P(x) \
+	SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
+		   (unsigned long long)(cpu_base->x))
+#define P_ns(x) \
+	SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
+		   (unsigned long long)(ktime_to_ns(cpu_base->x)))
+
+#ifdef CONFIG_HIGH_RES_TIMERS
+	P_ns(expires_next);
+	P(hres_active);
+	P(nr_events);
+	P(nr_retries);
+	P(nr_hangs);
+	P(max_hang_time);
+#endif
+#undef P
+#undef P_ns
+
+#ifdef CONFIG_TICK_ONESHOT
+# define P(x) \
+	SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
+		   (unsigned long long)(ts->x))
+# define P_ns(x) \
+	SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
+		   (unsigned long long)(ktime_to_ns(ts->x)))
+	{
+		struct tick_sched *ts = tick_get_tick_sched(cpu);
+		P(nohz_mode);
+		P_ns(last_tick);
+		P(tick_stopped);
+		P(idle_jiffies);
+		P(idle_calls);
+		P(idle_sleeps);
+		P_ns(idle_entrytime);
+		P_ns(idle_waketime);
+		P_ns(idle_exittime);
+		P_ns(idle_sleeptime);
+		P_ns(iowait_sleeptime);
+		P(last_jiffies);
+		P(next_timer);
+		P_ns(idle_expires);
+		SEQ_printf(m, "jiffies: %Lu\n",
+			   (unsigned long long)jiffies);
+	}
+#endif
+
+#undef P
+#undef P_ns
+	SEQ_printf(m, "\n");
+}
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS
+static void
+print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
+{
+	struct clock_event_device *dev = td->evtdev;
+
+	touch_nmi_watchdog();
+
+	SEQ_printf(m, "Tick Device: mode:     %d\n", td->mode);
+	if (cpu < 0)
+		SEQ_printf(m, "Broadcast device\n");
+	else
+		SEQ_printf(m, "Per CPU device: %d\n", cpu);
+
+	SEQ_printf(m, "Clock Event Device: ");
+	if (!dev) {
+		SEQ_printf(m, "<NULL>\n");
+		return;
+	}
+	SEQ_printf(m, "%s\n", dev->name);
+	SEQ_printf(m, " max_delta_ns:   %llu\n",
+		   (unsigned long long) dev->max_delta_ns);
+	SEQ_printf(m, " min_delta_ns:   %llu\n",
+		   (unsigned long long) dev->min_delta_ns);
+	SEQ_printf(m, " mult:           %u\n", dev->mult);
+	SEQ_printf(m, " shift:          %u\n", dev->shift);
+	SEQ_printf(m, " mode:           %d\n", clockevent_get_state(dev));
+	SEQ_printf(m, " next_event:     %Ld nsecs\n",
+		   (unsigned long long) ktime_to_ns(dev->next_event));
+
+	SEQ_printf(m, " set_next_event: %ps\n", dev->set_next_event);
+
+	if (dev->set_state_shutdown)
+		SEQ_printf(m, " shutdown:       %ps\n",
+			dev->set_state_shutdown);
+
+	if (dev->set_state_periodic)
+		SEQ_printf(m, " periodic:       %ps\n",
+			dev->set_state_periodic);
+
+	if (dev->set_state_oneshot)
+		SEQ_printf(m, " oneshot:        %ps\n",
+			dev->set_state_oneshot);
+
+	if (dev->set_state_oneshot_stopped)
+		SEQ_printf(m, " oneshot stopped: %ps\n",
+			dev->set_state_oneshot_stopped);
+
+	if (dev->tick_resume)
+		SEQ_printf(m, " resume:         %ps\n",
+			dev->tick_resume);
+
+	SEQ_printf(m, " event_handler:  %ps\n", dev->event_handler);
+	SEQ_printf(m, "\n");
+	SEQ_printf(m, " retries:        %lu\n", dev->retries);
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+	if (cpu >= 0) {
+		const struct clock_event_device *wd = tick_get_wakeup_device(cpu);
+
+		SEQ_printf(m, "Wakeup Device: %s\n", wd ? wd->name : "<NULL>");
+	}
+#endif
+	SEQ_printf(m, "\n");
+}
+
+static void timer_list_show_tickdevices_header(struct seq_file *m)
+{
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+	print_tickdevice(m, tick_get_broadcast_device(), -1);
+	SEQ_printf(m, "tick_broadcast_mask: %*pb\n",
+		   cpumask_pr_args(tick_get_broadcast_mask()));
+#ifdef CONFIG_TICK_ONESHOT
+	SEQ_printf(m, "tick_broadcast_oneshot_mask: %*pb\n",
+		   cpumask_pr_args(tick_get_broadcast_oneshot_mask()));
+#endif
+	SEQ_printf(m, "\n");
+#endif
+}
+#endif
+
+static inline void timer_list_header(struct seq_file *m, u64 now)
+{
+	SEQ_printf(m, "Timer List Version: v0.9\n");
+	SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
+	SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
+	SEQ_printf(m, "\n");
+}
+
+void sysrq_timer_list_show(void)
+{
+	u64 now = ktime_to_ns(ktime_get());
+	int cpu;
+
+	timer_list_header(NULL, now);
+
+	for_each_online_cpu(cpu)
+		print_cpu(NULL, cpu, now);
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS
+	timer_list_show_tickdevices_header(NULL);
+	for_each_online_cpu(cpu)
+		print_tickdevice(NULL, tick_get_device(cpu), cpu);
+#endif
+	return;
+}
+
+#ifdef CONFIG_PROC_FS
+static int timer_list_show(struct seq_file *m, void *v)
+{
+	struct timer_list_iter *iter = v;
+
+	if (iter->cpu == -1 && !iter->second_pass)
+		timer_list_header(m, iter->now);
+	else if (!iter->second_pass)
+		print_cpu(m, iter->cpu, iter->now);
+#ifdef CONFIG_GENERIC_CLOCKEVENTS
+	else if (iter->cpu == -1 && iter->second_pass)
+		timer_list_show_tickdevices_header(m);
+	else
+		print_tickdevice(m, tick_get_device(iter->cpu), iter->cpu);
+#endif
+	return 0;
+}
+
+static void *move_iter(struct timer_list_iter *iter, loff_t offset)
+{
+	for (; offset; offset--) {
+		iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
+		if (iter->cpu >= nr_cpu_ids) {
+#ifdef CONFIG_GENERIC_CLOCKEVENTS
+			if (!iter->second_pass) {
+				iter->cpu = -1;
+				iter->second_pass = true;
+			} else
+				return NULL;
+#else
+			return NULL;
+#endif
+		}
+	}
+	return iter;
+}
+
+static void *timer_list_start(struct seq_file *file, loff_t *offset)
+{
+	struct timer_list_iter *iter = file->private;
+
+	if (!*offset)
+		iter->now = ktime_to_ns(ktime_get());
+	iter->cpu = -1;
+	iter->second_pass = false;
+	return move_iter(iter, *offset);
+}
+
+static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
+{
+	struct timer_list_iter *iter = file->private;
+	++*offset;
+	return move_iter(iter, 1);
+}
+
+static void timer_list_stop(struct seq_file *seq, void *v)
+{
+}
+
+static const struct seq_operations timer_list_sops = {
+	.start = timer_list_start,
+	.next = timer_list_next,
+	.stop = timer_list_stop,
+	.show = timer_list_show,
+};
+
+static int __init init_timer_list_procfs(void)
+{
+	struct proc_dir_entry *pe;
+
+	pe = proc_create_seq_private("timer_list", 0400, NULL, &timer_list_sops,
+			sizeof(struct timer_list_iter), NULL);
+	if (!pe)
+		return -ENOMEM;
+	return 0;
+}
+__initcall(init_timer_list_procfs);
+#endif
diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c
new file mode 100644
index 000000000..f0d5062d9
--- /dev/null
+++ b/kernel/time/vsyscall.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 ARM Ltd.
+ *
+ * Generic implementation of update_vsyscall and update_vsyscall_tz.
+ *
+ * Based on the x86 specific implementation.
+ */
+
+#include <linux/hrtimer.h>
+#include <linux/timekeeper_internal.h>
+#include <vdso/datapage.h>
+#include <vdso/helpers.h>
+#include <vdso/vsyscall.h>
+
+#include "timekeeping_internal.h"
+
+static inline void update_vdso_data(struct vdso_data *vdata,
+				    struct timekeeper *tk)
+{
+	struct vdso_timestamp *vdso_ts;
+	u64 nsec, sec;
+
+	vdata[CS_HRES_COARSE].cycle_last	= tk->tkr_mono.cycle_last;
+	vdata[CS_HRES_COARSE].mask		= tk->tkr_mono.mask;
+	vdata[CS_HRES_COARSE].mult		= tk->tkr_mono.mult;
+	vdata[CS_HRES_COARSE].shift		= tk->tkr_mono.shift;
+	vdata[CS_RAW].cycle_last		= tk->tkr_raw.cycle_last;
+	vdata[CS_RAW].mask			= tk->tkr_raw.mask;
+	vdata[CS_RAW].mult			= tk->tkr_raw.mult;
+	vdata[CS_RAW].shift			= tk->tkr_raw.shift;
+
+	/* CLOCK_MONOTONIC */
+	vdso_ts		= &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC];
+	vdso_ts->sec	= tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
+
+	nsec = tk->tkr_mono.xtime_nsec;
+	nsec += ((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
+	while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
+		nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
+		vdso_ts->sec++;
+	}
+	vdso_ts->nsec	= nsec;
+
+	/* Copy MONOTONIC time for BOOTTIME */
+	sec	= vdso_ts->sec;
+	/* Add the boot offset */
+	sec	+= tk->monotonic_to_boot.tv_sec;
+	nsec	+= (u64)tk->monotonic_to_boot.tv_nsec << tk->tkr_mono.shift;
+
+	/* CLOCK_BOOTTIME */
+	vdso_ts		= &vdata[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME];
+	vdso_ts->sec	= sec;
+
+	while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
+		nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
+		vdso_ts->sec++;
+	}
+	vdso_ts->nsec	= nsec;
+
+	/* CLOCK_MONOTONIC_RAW */
+	vdso_ts		= &vdata[CS_RAW].basetime[CLOCK_MONOTONIC_RAW];
+	vdso_ts->sec	= tk->raw_sec;
+	vdso_ts->nsec	= tk->tkr_raw.xtime_nsec;
+
+	/* CLOCK_TAI */
+	vdso_ts		= &vdata[CS_HRES_COARSE].basetime[CLOCK_TAI];
+	vdso_ts->sec	= tk->xtime_sec + (s64)tk->tai_offset;
+	vdso_ts->nsec	= tk->tkr_mono.xtime_nsec;
+}
+
+void update_vsyscall(struct timekeeper *tk)
+{
+	struct vdso_data *vdata = __arch_get_k_vdso_data();
+	struct vdso_timestamp *vdso_ts;
+	s32 clock_mode;
+	u64 nsec;
+
+	/* copy vsyscall data */
+	vdso_write_begin(vdata);
+
+	clock_mode = tk->tkr_mono.clock->vdso_clock_mode;
+	vdata[CS_HRES_COARSE].clock_mode	= clock_mode;
+	vdata[CS_RAW].clock_mode		= clock_mode;
+
+	/* CLOCK_REALTIME also required for time() */
+	vdso_ts		= &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME];
+	vdso_ts->sec	= tk->xtime_sec;
+	vdso_ts->nsec	= tk->tkr_mono.xtime_nsec;
+
+	/* CLOCK_REALTIME_COARSE */
+	vdso_ts		= &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME_COARSE];
+	vdso_ts->sec	= tk->xtime_sec;
+	vdso_ts->nsec	= tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
+
+	/* CLOCK_MONOTONIC_COARSE */
+	vdso_ts		= &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC_COARSE];
+	vdso_ts->sec	= tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
+	nsec		= tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
+	nsec		= nsec + tk->wall_to_monotonic.tv_nsec;
+	vdso_ts->sec	+= __iter_div_u64_rem(nsec, NSEC_PER_SEC, &vdso_ts->nsec);
+
+	/*
+	 * Read without the seqlock held by clock_getres().
+	 * Note: No need to have a second copy.
+	 */
+	WRITE_ONCE(vdata[CS_HRES_COARSE].hrtimer_res, hrtimer_resolution);
+
+	/*
+	 * If the current clocksource is not VDSO capable, then spare the
+	 * update of the high resolution parts.
+	 */
+	if (clock_mode != VDSO_CLOCKMODE_NONE)
+		update_vdso_data(vdata, tk);
+
+	__arch_update_vsyscall(vdata, tk);
+
+	vdso_write_end(vdata);
+
+	__arch_sync_vdso_data(vdata);
+}
+
+void update_vsyscall_tz(void)
+{
+	struct vdso_data *vdata = __arch_get_k_vdso_data();
+
+	vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest;
+	vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime;
+
+	__arch_sync_vdso_data(vdata);
+}
+
+/**
+ * vdso_update_begin - Start of a VDSO update section
+ *
+ * Allows architecture code to safely update the architecture specific VDSO
+ * data. Disables interrupts, acquires timekeeper lock to serialize against
+ * concurrent updates from timekeeping and invalidates the VDSO data
+ * sequence counter to prevent concurrent readers from accessing
+ * inconsistent data.
+ *
+ * Returns: Saved interrupt flags which need to be handed in to
+ * vdso_update_end().
+ */
+unsigned long vdso_update_begin(void)
+{
+	struct vdso_data *vdata = __arch_get_k_vdso_data();
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	vdso_write_begin(vdata);
+	return flags;
+}
+
+/**
+ * vdso_update_end - End of a VDSO update section
+ * @flags:	Interrupt flags as returned from vdso_update_begin()
+ *
+ * Pairs with vdso_update_begin(). Marks vdso data consistent, invokes data
+ * synchronization if the architecture requires it, drops timekeeper lock
+ * and restores interrupt flags.
+ */
+void vdso_update_end(unsigned long flags)
+{
+	struct vdso_data *vdata = __arch_get_k_vdso_data();
+
+	vdso_write_end(vdata);
+	__arch_sync_vdso_data(vdata);
+	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+}
diff --git a/kernel/torture.c b/kernel/torture.c
new file mode 100644
index 000000000..9266ca168
--- /dev/null
+++ b/kernel/torture.c
@@ -0,0 +1,958 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Common functions for in-kernel torture tests.
+ *
+ * Copyright (C) IBM Corporation, 2014
+ *
+ * Author: Paul E. McKenney <paulmck@linux.ibm.com>
+ *	Based on kernel/rcu/torture.c.
+ */
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/err.h>
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/sched/clock.h>
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/moduleparam.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/freezer.h>
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/trace_clock.h>
+#include <linux/ktime.h>
+#include <asm/byteorder.h>
+#include <linux/torture.h>
+#include "rcu/rcu.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
+
+static bool disable_onoff_at_boot;
+module_param(disable_onoff_at_boot, bool, 0444);
+
+static bool ftrace_dump_at_shutdown;
+module_param(ftrace_dump_at_shutdown, bool, 0444);
+
+static int verbose_sleep_frequency;
+module_param(verbose_sleep_frequency, int, 0444);
+
+static int verbose_sleep_duration = 1;
+module_param(verbose_sleep_duration, int, 0444);
+
+static char *torture_type;
+static int verbose;
+
+/* Mediate rmmod and system shutdown.  Concurrent rmmod & shutdown illegal! */
+#define FULLSTOP_DONTSTOP 0	/* Normal operation. */
+#define FULLSTOP_SHUTDOWN 1	/* System shutdown with torture running. */
+#define FULLSTOP_RMMOD    2	/* Normal rmmod of torture. */
+static int fullstop = FULLSTOP_RMMOD;
+static DEFINE_MUTEX(fullstop_mutex);
+
+static atomic_t verbose_sleep_counter;
+
+/*
+ * Sleep if needed from VERBOSE_TOROUT*().
+ */
+void verbose_torout_sleep(void)
+{
+	if (verbose_sleep_frequency > 0 &&
+	    verbose_sleep_duration > 0 &&
+	    !(atomic_inc_return(&verbose_sleep_counter) % verbose_sleep_frequency))
+		schedule_timeout_uninterruptible(verbose_sleep_duration);
+}
+EXPORT_SYMBOL_GPL(verbose_torout_sleep);
+
+/*
+ * Schedule a high-resolution-timer sleep in nanoseconds, with a 32-bit
+ * nanosecond random fuzz.  This function and its friends desynchronize
+ * testing from the timer wheel.
+ */
+int torture_hrtimeout_ns(ktime_t baset_ns, u32 fuzzt_ns, struct torture_random_state *trsp)
+{
+	ktime_t hto = baset_ns;
+
+	if (trsp)
+		hto += (torture_random(trsp) >> 3) % fuzzt_ns;
+	set_current_state(TASK_UNINTERRUPTIBLE);
+	return schedule_hrtimeout(&hto, HRTIMER_MODE_REL);
+}
+EXPORT_SYMBOL_GPL(torture_hrtimeout_ns);
+
+/*
+ * Schedule a high-resolution-timer sleep in microseconds, with a 32-bit
+ * nanosecond (not microsecond!) random fuzz.
+ */
+int torture_hrtimeout_us(u32 baset_us, u32 fuzzt_ns, struct torture_random_state *trsp)
+{
+	ktime_t baset_ns = baset_us * NSEC_PER_USEC;
+
+	return torture_hrtimeout_ns(baset_ns, fuzzt_ns, trsp);
+}
+EXPORT_SYMBOL_GPL(torture_hrtimeout_us);
+
+/*
+ * Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit
+ * microsecond (not millisecond!) random fuzz.
+ */
+int torture_hrtimeout_ms(u32 baset_ms, u32 fuzzt_us, struct torture_random_state *trsp)
+{
+	ktime_t baset_ns = baset_ms * NSEC_PER_MSEC;
+	u32 fuzzt_ns;
+
+	if ((u32)~0U / NSEC_PER_USEC < fuzzt_us)
+		fuzzt_ns = (u32)~0U;
+	else
+		fuzzt_ns = fuzzt_us * NSEC_PER_USEC;
+	return torture_hrtimeout_ns(baset_ns, fuzzt_ns, trsp);
+}
+EXPORT_SYMBOL_GPL(torture_hrtimeout_ms);
+
+/*
+ * Schedule a high-resolution-timer sleep in jiffies, with an
+ * implied one-jiffy random fuzz.  This is intended to replace calls to
+ * schedule_timeout_interruptible() and friends.
+ */
+int torture_hrtimeout_jiffies(u32 baset_j, struct torture_random_state *trsp)
+{
+	ktime_t baset_ns = jiffies_to_nsecs(baset_j);
+
+	return torture_hrtimeout_ns(baset_ns, jiffies_to_nsecs(1), trsp);
+}
+EXPORT_SYMBOL_GPL(torture_hrtimeout_jiffies);
+
+/*
+ * Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit
+ * millisecond (not second!) random fuzz.
+ */
+int torture_hrtimeout_s(u32 baset_s, u32 fuzzt_ms, struct torture_random_state *trsp)
+{
+	ktime_t baset_ns = baset_s * NSEC_PER_SEC;
+	u32 fuzzt_ns;
+
+	if ((u32)~0U / NSEC_PER_MSEC < fuzzt_ms)
+		fuzzt_ns = (u32)~0U;
+	else
+		fuzzt_ns = fuzzt_ms * NSEC_PER_MSEC;
+	return torture_hrtimeout_ns(baset_ns, fuzzt_ns, trsp);
+}
+EXPORT_SYMBOL_GPL(torture_hrtimeout_s);
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+/*
+ * Variables for online-offline handling.  Only present if CPU hotplug
+ * is enabled, otherwise does nothing.
+ */
+
+static struct task_struct *onoff_task;
+static long onoff_holdoff;
+static long onoff_interval;
+static torture_ofl_func *onoff_f;
+static long n_offline_attempts;
+static long n_offline_successes;
+static unsigned long sum_offline;
+static int min_offline = -1;
+static int max_offline;
+static long n_online_attempts;
+static long n_online_successes;
+static unsigned long sum_online;
+static int min_online = -1;
+static int max_online;
+
+static int torture_online_cpus = NR_CPUS;
+
+/*
+ * Some torture testing leverages confusion as to the number of online
+ * CPUs.  This function returns the torture-testing view of this number,
+ * which allows torture tests to load-balance appropriately.
+ */
+int torture_num_online_cpus(void)
+{
+	return READ_ONCE(torture_online_cpus);
+}
+EXPORT_SYMBOL_GPL(torture_num_online_cpus);
+
+/*
+ * Attempt to take a CPU offline.  Return false if the CPU is already
+ * offline or if it is not subject to CPU-hotplug operations.  The
+ * caller can detect other failures by looking at the statistics.
+ */
+bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
+		     unsigned long *sum_offl, int *min_offl, int *max_offl)
+{
+	unsigned long delta;
+	int ret;
+	char *s;
+	unsigned long starttime;
+
+	if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
+		return false;
+	if (num_online_cpus() <= 1)
+		return false;  /* Can't offline the last CPU. */
+
+	if (verbose > 1)
+		pr_alert("%s" TORTURE_FLAG
+			 "torture_onoff task: offlining %d\n",
+			 torture_type, cpu);
+	starttime = jiffies;
+	(*n_offl_attempts)++;
+	ret = remove_cpu(cpu);
+	if (ret) {
+		s = "";
+		if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) {
+			// PCI probe frequently disables hotplug during boot.
+			(*n_offl_attempts)--;
+			s = " (-EBUSY forgiven during boot)";
+		}
+		if (verbose)
+			pr_alert("%s" TORTURE_FLAG
+				 "torture_onoff task: offline %d failed%s: errno %d\n",
+				 torture_type, cpu, s, ret);
+	} else {
+		if (verbose > 1)
+			pr_alert("%s" TORTURE_FLAG
+				 "torture_onoff task: offlined %d\n",
+				 torture_type, cpu);
+		if (onoff_f)
+			onoff_f();
+		(*n_offl_successes)++;
+		delta = jiffies - starttime;
+		*sum_offl += delta;
+		if (*min_offl < 0) {
+			*min_offl = delta;
+			*max_offl = delta;
+		}
+		if (*min_offl > delta)
+			*min_offl = delta;
+		if (*max_offl < delta)
+			*max_offl = delta;
+		WRITE_ONCE(torture_online_cpus, torture_online_cpus - 1);
+		WARN_ON_ONCE(torture_online_cpus <= 0);
+	}
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(torture_offline);
+
+/*
+ * Attempt to bring a CPU online.  Return false if the CPU is already
+ * online or if it is not subject to CPU-hotplug operations.  The
+ * caller can detect other failures by looking at the statistics.
+ */
+bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
+		    unsigned long *sum_onl, int *min_onl, int *max_onl)
+{
+	unsigned long delta;
+	int ret;
+	char *s;
+	unsigned long starttime;
+
+	if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
+		return false;
+
+	if (verbose > 1)
+		pr_alert("%s" TORTURE_FLAG
+			 "torture_onoff task: onlining %d\n",
+			 torture_type, cpu);
+	starttime = jiffies;
+	(*n_onl_attempts)++;
+	ret = add_cpu(cpu);
+	if (ret) {
+		s = "";
+		if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) {
+			// PCI probe frequently disables hotplug during boot.
+			(*n_onl_attempts)--;
+			s = " (-EBUSY forgiven during boot)";
+		}
+		if (verbose)
+			pr_alert("%s" TORTURE_FLAG
+				 "torture_onoff task: online %d failed%s: errno %d\n",
+				 torture_type, cpu, s, ret);
+	} else {
+		if (verbose > 1)
+			pr_alert("%s" TORTURE_FLAG
+				 "torture_onoff task: onlined %d\n",
+				 torture_type, cpu);
+		(*n_onl_successes)++;
+		delta = jiffies - starttime;
+		*sum_onl += delta;
+		if (*min_onl < 0) {
+			*min_onl = delta;
+			*max_onl = delta;
+		}
+		if (*min_onl > delta)
+			*min_onl = delta;
+		if (*max_onl < delta)
+			*max_onl = delta;
+		WRITE_ONCE(torture_online_cpus, torture_online_cpus + 1);
+	}
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(torture_online);
+
+/*
+ * Get everything online at the beginning and ends of tests.
+ */
+static void torture_online_all(char *phase)
+{
+	int cpu;
+	int ret;
+
+	for_each_possible_cpu(cpu) {
+		if (cpu_online(cpu))
+			continue;
+		ret = add_cpu(cpu);
+		if (ret && verbose) {
+			pr_alert("%s" TORTURE_FLAG
+				 "%s: %s online %d: errno %d\n",
+				 __func__, phase, torture_type, cpu, ret);
+		}
+	}
+}
+
+/*
+ * Execute random CPU-hotplug operations at the interval specified
+ * by the onoff_interval.
+ */
+static int
+torture_onoff(void *arg)
+{
+	int cpu;
+	int maxcpu = -1;
+	DEFINE_TORTURE_RANDOM(rand);
+
+	VERBOSE_TOROUT_STRING("torture_onoff task started");
+	for_each_online_cpu(cpu)
+		maxcpu = cpu;
+	WARN_ON(maxcpu < 0);
+	torture_online_all("Initial");
+	if (maxcpu == 0) {
+		VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
+		goto stop;
+	}
+
+	if (onoff_holdoff > 0) {
+		VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
+		schedule_timeout_interruptible(onoff_holdoff);
+		VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
+	}
+	while (!torture_must_stop()) {
+		if (disable_onoff_at_boot && !rcu_inkernel_boot_has_ended()) {
+			schedule_timeout_interruptible(HZ / 10);
+			continue;
+		}
+		cpu = (torture_random(&rand) >> 4) % (maxcpu + 1);
+		if (!torture_offline(cpu,
+				     &n_offline_attempts, &n_offline_successes,
+				     &sum_offline, &min_offline, &max_offline))
+			torture_online(cpu,
+				       &n_online_attempts, &n_online_successes,
+				       &sum_online, &min_online, &max_online);
+		schedule_timeout_interruptible(onoff_interval);
+	}
+
+stop:
+	torture_kthread_stopping("torture_onoff");
+	torture_online_all("Final");
+	return 0;
+}
+
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+
+/*
+ * Initiate online-offline handling.
+ */
+int torture_onoff_init(long ooholdoff, long oointerval, torture_ofl_func *f)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+	onoff_holdoff = ooholdoff;
+	onoff_interval = oointerval;
+	onoff_f = f;
+	if (onoff_interval <= 0)
+		return 0;
+	return torture_create_kthread(torture_onoff, NULL, onoff_task);
+#else /* #ifdef CONFIG_HOTPLUG_CPU */
+	return 0;
+#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
+}
+EXPORT_SYMBOL_GPL(torture_onoff_init);
+
+/*
+ * Clean up after online/offline testing.
+ */
+static void torture_onoff_cleanup(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+	if (onoff_task == NULL)
+		return;
+	VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
+	kthread_stop(onoff_task);
+	onoff_task = NULL;
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+}
+
+/*
+ * Print online/offline testing statistics.
+ */
+void torture_onoff_stats(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+	pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
+		n_online_successes, n_online_attempts,
+		n_offline_successes, n_offline_attempts,
+		min_online, max_online,
+		min_offline, max_offline,
+		sum_online, sum_offline, HZ);
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+}
+EXPORT_SYMBOL_GPL(torture_onoff_stats);
+
+/*
+ * Were all the online/offline operations successful?
+ */
+bool torture_onoff_failures(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+	return n_online_successes != n_online_attempts ||
+	       n_offline_successes != n_offline_attempts;
+#else /* #ifdef CONFIG_HOTPLUG_CPU */
+	return false;
+#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
+}
+EXPORT_SYMBOL_GPL(torture_onoff_failures);
+
+#define TORTURE_RANDOM_MULT	39916801  /* prime */
+#define TORTURE_RANDOM_ADD	479001701 /* prime */
+#define TORTURE_RANDOM_REFRESH	10000
+
+/*
+ * Crude but fast random-number generator.  Uses a linear congruential
+ * generator, with occasional help from cpu_clock().
+ */
+unsigned long
+torture_random(struct torture_random_state *trsp)
+{
+	if (--trsp->trs_count < 0) {
+		trsp->trs_state += (unsigned long)local_clock();
+		trsp->trs_count = TORTURE_RANDOM_REFRESH;
+	}
+	trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
+		TORTURE_RANDOM_ADD;
+	return swahw32(trsp->trs_state);
+}
+EXPORT_SYMBOL_GPL(torture_random);
+
+/*
+ * Variables for shuffling.  The idea is to ensure that each CPU stays
+ * idle for an extended period to test interactions with dyntick idle,
+ * as well as interactions with any per-CPU variables.
+ */
+struct shuffle_task {
+	struct list_head st_l;
+	struct task_struct *st_t;
+};
+
+static long shuffle_interval;	/* In jiffies. */
+static struct task_struct *shuffler_task;
+static cpumask_var_t shuffle_tmp_mask;
+static int shuffle_idle_cpu;	/* Force all torture tasks off this CPU */
+static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
+static DEFINE_MUTEX(shuffle_task_mutex);
+
+/*
+ * Register a task to be shuffled.  If there is no memory, just splat
+ * and don't bother registering.
+ */
+void torture_shuffle_task_register(struct task_struct *tp)
+{
+	struct shuffle_task *stp;
+
+	if (WARN_ON_ONCE(tp == NULL))
+		return;
+	stp = kmalloc(sizeof(*stp), GFP_KERNEL);
+	if (WARN_ON_ONCE(stp == NULL))
+		return;
+	stp->st_t = tp;
+	mutex_lock(&shuffle_task_mutex);
+	list_add(&stp->st_l, &shuffle_task_list);
+	mutex_unlock(&shuffle_task_mutex);
+}
+EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
+
+/*
+ * Unregister all tasks, for example, at the end of the torture run.
+ */
+static void torture_shuffle_task_unregister_all(void)
+{
+	struct shuffle_task *stp;
+	struct shuffle_task *p;
+
+	mutex_lock(&shuffle_task_mutex);
+	list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
+		list_del(&stp->st_l);
+		kfree(stp);
+	}
+	mutex_unlock(&shuffle_task_mutex);
+}
+
+/* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
+ * A special case is when shuffle_idle_cpu = -1, in which case we allow
+ * the tasks to run on all CPUs.
+ */
+static void torture_shuffle_tasks(void)
+{
+	struct shuffle_task *stp;
+
+	cpumask_setall(shuffle_tmp_mask);
+	cpus_read_lock();
+
+	/* No point in shuffling if there is only one online CPU (ex: UP) */
+	if (num_online_cpus() == 1) {
+		cpus_read_unlock();
+		return;
+	}
+
+	/* Advance to the next CPU.  Upon overflow, don't idle any CPUs. */
+	shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
+	if (shuffle_idle_cpu >= nr_cpu_ids)
+		shuffle_idle_cpu = -1;
+	else
+		cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
+
+	mutex_lock(&shuffle_task_mutex);
+	list_for_each_entry(stp, &shuffle_task_list, st_l)
+		set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
+	mutex_unlock(&shuffle_task_mutex);
+
+	cpus_read_unlock();
+}
+
+/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
+ * system to become idle at a time and cut off its timer ticks. This is meant
+ * to test the support for such tickless idle CPU in RCU.
+ */
+static int torture_shuffle(void *arg)
+{
+	VERBOSE_TOROUT_STRING("torture_shuffle task started");
+	do {
+		schedule_timeout_interruptible(shuffle_interval);
+		torture_shuffle_tasks();
+		torture_shutdown_absorb("torture_shuffle");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("torture_shuffle");
+	return 0;
+}
+
+/*
+ * Start the shuffler, with shuffint in jiffies.
+ */
+int torture_shuffle_init(long shuffint)
+{
+	shuffle_interval = shuffint;
+
+	shuffle_idle_cpu = -1;
+
+	if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
+		TOROUT_ERRSTRING("Failed to alloc mask");
+		return -ENOMEM;
+	}
+
+	/* Create the shuffler thread */
+	return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
+}
+EXPORT_SYMBOL_GPL(torture_shuffle_init);
+
+/*
+ * Stop the shuffling.
+ */
+static void torture_shuffle_cleanup(void)
+{
+	torture_shuffle_task_unregister_all();
+	if (shuffler_task) {
+		VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
+		kthread_stop(shuffler_task);
+		free_cpumask_var(shuffle_tmp_mask);
+	}
+	shuffler_task = NULL;
+}
+
+/*
+ * Variables for auto-shutdown.  This allows "lights out" torture runs
+ * to be fully scripted.
+ */
+static struct task_struct *shutdown_task;
+static ktime_t shutdown_time;		/* time to system shutdown. */
+static void (*torture_shutdown_hook)(void);
+
+/*
+ * Absorb kthreads into a kernel function that won't return, so that
+ * they won't ever access module text or data again.
+ */
+void torture_shutdown_absorb(const char *title)
+{
+	while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
+		pr_notice("torture thread %s parking due to system shutdown\n",
+			  title);
+		schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
+	}
+}
+EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
+
+/*
+ * Cause the torture test to shutdown the system after the test has
+ * run for the time specified by the shutdown_secs parameter.
+ */
+static int torture_shutdown(void *arg)
+{
+	ktime_t ktime_snap;
+
+	VERBOSE_TOROUT_STRING("torture_shutdown task started");
+	ktime_snap = ktime_get();
+	while (ktime_before(ktime_snap, shutdown_time) &&
+	       !torture_must_stop()) {
+		if (verbose)
+			pr_alert("%s" TORTURE_FLAG
+				 "torture_shutdown task: %llu ms remaining\n",
+				 torture_type,
+				 ktime_ms_delta(shutdown_time, ktime_snap));
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS);
+		ktime_snap = ktime_get();
+	}
+	if (torture_must_stop()) {
+		torture_kthread_stopping("torture_shutdown");
+		return 0;
+	}
+
+	/* OK, shut down the system. */
+
+	VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
+	shutdown_task = NULL;	/* Avoid self-kill deadlock. */
+	if (torture_shutdown_hook)
+		torture_shutdown_hook();
+	else
+		VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
+	if (ftrace_dump_at_shutdown)
+		rcu_ftrace_dump(DUMP_ALL);
+	kernel_power_off();	/* Shut down the system. */
+	return 0;
+}
+
+/*
+ * Start up the shutdown task.
+ */
+int torture_shutdown_init(int ssecs, void (*cleanup)(void))
+{
+	torture_shutdown_hook = cleanup;
+	if (ssecs > 0) {
+		shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
+		return torture_create_kthread(torture_shutdown, NULL,
+					     shutdown_task);
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(torture_shutdown_init);
+
+/*
+ * Detect and respond to a system shutdown.
+ */
+static int torture_shutdown_notify(struct notifier_block *unused1,
+				   unsigned long unused2, void *unused3)
+{
+	mutex_lock(&fullstop_mutex);
+	if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
+		VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
+		WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN);
+	} else {
+		pr_warn("Concurrent rmmod and shutdown illegal!\n");
+	}
+	mutex_unlock(&fullstop_mutex);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block torture_shutdown_nb = {
+	.notifier_call = torture_shutdown_notify,
+};
+
+/*
+ * Shut down the shutdown task.  Say what???  Heh!  This can happen if
+ * the torture module gets an rmmod before the shutdown time arrives.  ;-)
+ */
+static void torture_shutdown_cleanup(void)
+{
+	unregister_reboot_notifier(&torture_shutdown_nb);
+	if (shutdown_task != NULL) {
+		VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
+		kthread_stop(shutdown_task);
+	}
+	shutdown_task = NULL;
+}
+
+/*
+ * Variables for stuttering, which means to periodically pause and
+ * restart testing in order to catch bugs that appear when load is
+ * suddenly applied to or removed from the system.
+ */
+static struct task_struct *stutter_task;
+static int stutter_pause_test;
+static int stutter;
+static int stutter_gap;
+
+/*
+ * Block until the stutter interval ends.  This must be called periodically
+ * by all running kthreads that need to be subject to stuttering.
+ */
+bool stutter_wait(const char *title)
+{
+	unsigned int i = 0;
+	bool ret = false;
+	int spt;
+
+	cond_resched_tasks_rcu_qs();
+	spt = READ_ONCE(stutter_pause_test);
+	for (; spt; spt = READ_ONCE(stutter_pause_test)) {
+		if (!ret) {
+			sched_set_normal(current, MAX_NICE);
+			ret = true;
+		}
+		if (spt == 1) {
+			schedule_timeout_interruptible(1);
+		} else if (spt == 2) {
+			while (READ_ONCE(stutter_pause_test)) {
+				if (!(i++ & 0xffff))
+					torture_hrtimeout_us(10, 0, NULL);
+				cond_resched();
+			}
+		} else {
+			schedule_timeout_interruptible(round_jiffies_relative(HZ));
+		}
+		torture_shutdown_absorb(title);
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(stutter_wait);
+
+/*
+ * Cause the torture test to "stutter", starting and stopping all
+ * threads periodically.
+ */
+static int torture_stutter(void *arg)
+{
+	DEFINE_TORTURE_RANDOM(rand);
+	int wtime;
+
+	VERBOSE_TOROUT_STRING("torture_stutter task started");
+	do {
+		if (!torture_must_stop() && stutter > 1) {
+			wtime = stutter;
+			if (stutter > 2) {
+				WRITE_ONCE(stutter_pause_test, 1);
+				wtime = stutter - 3;
+				torture_hrtimeout_jiffies(wtime, &rand);
+				wtime = 2;
+			}
+			WRITE_ONCE(stutter_pause_test, 2);
+			torture_hrtimeout_jiffies(wtime, NULL);
+		}
+		WRITE_ONCE(stutter_pause_test, 0);
+		if (!torture_must_stop())
+			torture_hrtimeout_jiffies(stutter_gap, NULL);
+		torture_shutdown_absorb("torture_stutter");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("torture_stutter");
+	return 0;
+}
+
+/*
+ * Initialize and kick off the torture_stutter kthread.
+ */
+int torture_stutter_init(const int s, const int sgap)
+{
+	stutter = s;
+	stutter_gap = sgap;
+	return torture_create_kthread(torture_stutter, NULL, stutter_task);
+}
+EXPORT_SYMBOL_GPL(torture_stutter_init);
+
+/*
+ * Cleanup after the torture_stutter kthread.
+ */
+static void torture_stutter_cleanup(void)
+{
+	if (!stutter_task)
+		return;
+	VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
+	kthread_stop(stutter_task);
+	stutter_task = NULL;
+}
+
+/*
+ * Initialize torture module.  Please note that this is -not- invoked via
+ * the usual module_init() mechanism, but rather by an explicit call from
+ * the client torture module.  This call must be paired with a later
+ * torture_init_end().
+ *
+ * The runnable parameter points to a flag that controls whether or not
+ * the test is currently runnable.  If there is no such flag, pass in NULL.
+ */
+bool torture_init_begin(char *ttype, int v)
+{
+	mutex_lock(&fullstop_mutex);
+	if (torture_type != NULL) {
+		pr_alert("%s: Refusing %s init: %s running.\n",
+			  __func__, ttype, torture_type);
+		pr_alert("%s: One torture test at a time!\n", __func__);
+		mutex_unlock(&fullstop_mutex);
+		return false;
+	}
+	torture_type = ttype;
+	verbose = v;
+	fullstop = FULLSTOP_DONTSTOP;
+	return true;
+}
+EXPORT_SYMBOL_GPL(torture_init_begin);
+
+/*
+ * Tell the torture module that initialization is complete.
+ */
+void torture_init_end(void)
+{
+	mutex_unlock(&fullstop_mutex);
+	register_reboot_notifier(&torture_shutdown_nb);
+}
+EXPORT_SYMBOL_GPL(torture_init_end);
+
+/*
+ * Clean up torture module.  Please note that this is -not- invoked via
+ * the usual module_exit() mechanism, but rather by an explicit call from
+ * the client torture module.  Returns true if a race with system shutdown
+ * is detected, otherwise, all kthreads started by functions in this file
+ * will be shut down.
+ *
+ * This must be called before the caller starts shutting down its own
+ * kthreads.
+ *
+ * Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
+ * in order to correctly perform the cleanup. They are separated because
+ * threads can still need to reference the torture_type type, thus nullify
+ * only after completing all other relevant calls.
+ */
+bool torture_cleanup_begin(void)
+{
+	mutex_lock(&fullstop_mutex);
+	if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
+		pr_warn("Concurrent rmmod and shutdown illegal!\n");
+		mutex_unlock(&fullstop_mutex);
+		schedule_timeout_uninterruptible(10);
+		return true;
+	}
+	WRITE_ONCE(fullstop, FULLSTOP_RMMOD);
+	mutex_unlock(&fullstop_mutex);
+	torture_shutdown_cleanup();
+	torture_shuffle_cleanup();
+	torture_stutter_cleanup();
+	torture_onoff_cleanup();
+	return false;
+}
+EXPORT_SYMBOL_GPL(torture_cleanup_begin);
+
+void torture_cleanup_end(void)
+{
+	mutex_lock(&fullstop_mutex);
+	torture_type = NULL;
+	mutex_unlock(&fullstop_mutex);
+}
+EXPORT_SYMBOL_GPL(torture_cleanup_end);
+
+/*
+ * Is it time for the current torture test to stop?
+ */
+bool torture_must_stop(void)
+{
+	return torture_must_stop_irq() || kthread_should_stop();
+}
+EXPORT_SYMBOL_GPL(torture_must_stop);
+
+/*
+ * Is it time for the current torture test to stop?  This is the irq-safe
+ * version, hence no check for kthread_should_stop().
+ */
+bool torture_must_stop_irq(void)
+{
+	return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP;
+}
+EXPORT_SYMBOL_GPL(torture_must_stop_irq);
+
+/*
+ * Each kthread must wait for kthread_should_stop() before returning from
+ * its top-level function, otherwise segfaults ensue.  This function
+ * prints a "stopping" message and waits for kthread_should_stop(), and
+ * should be called from all torture kthreads immediately prior to
+ * returning.
+ */
+void torture_kthread_stopping(char *title)
+{
+	char buf[128];
+
+	snprintf(buf, sizeof(buf), "%s is stopping", title);
+	VERBOSE_TOROUT_STRING(buf);
+	while (!kthread_should_stop()) {
+		torture_shutdown_absorb(title);
+		schedule_timeout_uninterruptible(HZ / 20);
+	}
+}
+EXPORT_SYMBOL_GPL(torture_kthread_stopping);
+
+/*
+ * Create a generic torture kthread that is immediately runnable.  If you
+ * need the kthread to be stopped so that you can do something to it before
+ * it starts, you will need to open-code your own.
+ */
+int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
+			    char *f, struct task_struct **tp)
+{
+	int ret = 0;
+
+	VERBOSE_TOROUT_STRING(m);
+	*tp = kthread_create(fn, arg, "%s", s);
+	if (IS_ERR(*tp)) {
+		ret = PTR_ERR(*tp);
+		TOROUT_ERRSTRING(f);
+		*tp = NULL;
+		return ret;
+	}
+	wake_up_process(*tp);  // Process is sleeping, so ordering provided.
+	torture_shuffle_task_register(*tp);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(_torture_create_kthread);
+
+/*
+ * Stop a generic kthread, emitting a message.
+ */
+void _torture_stop_kthread(char *m, struct task_struct **tp)
+{
+	if (*tp == NULL)
+		return;
+	VERBOSE_TOROUT_STRING(m);
+	kthread_stop(*tp);
+	*tp = NULL;
+}
+EXPORT_SYMBOL_GPL(_torture_stop_kthread);
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
new file mode 100644
index 000000000..93d724996
--- /dev/null
+++ b/kernel/trace/Kconfig
@@ -0,0 +1,1119 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Architectures that offer an FUNCTION_TRACER implementation should
+#  select HAVE_FUNCTION_TRACER:
+#
+
+config USER_STACKTRACE_SUPPORT
+	bool
+
+config NOP_TRACER
+	bool
+
+config HAVE_RETHOOK
+	bool
+
+config RETHOOK
+	bool
+	depends on HAVE_RETHOOK
+	help
+	  Enable generic return hooking feature. This is an internal
+	  API, which will be used by other function-entry hooking
+	  features like fprobe and kprobes.
+
+config HAVE_FUNCTION_TRACER
+	bool
+	help
+	  See Documentation/trace/ftrace-design.rst
+
+config HAVE_FUNCTION_GRAPH_TRACER
+	bool
+	help
+	  See Documentation/trace/ftrace-design.rst
+
+config HAVE_DYNAMIC_FTRACE
+	bool
+	help
+	  See Documentation/trace/ftrace-design.rst
+
+config HAVE_DYNAMIC_FTRACE_WITH_REGS
+	bool
+
+config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	bool
+
+config HAVE_DYNAMIC_FTRACE_WITH_ARGS
+	bool
+	help
+	 If this is set, then arguments and stack can be found from
+	 the pt_regs passed into the function callback regs parameter
+	 by default, even without setting the REGS flag in the ftrace_ops.
+	 This allows for use of regs_get_kernel_argument() and
+	 kernel_stack_pointer().
+
+config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
+	bool
+	help
+	  If the architecture generates __patchable_function_entries sections
+	  but does not want them included in the ftrace locations.
+
+config HAVE_FTRACE_MCOUNT_RECORD
+	bool
+	help
+	  See Documentation/trace/ftrace-design.rst
+
+config HAVE_SYSCALL_TRACEPOINTS
+	bool
+	help
+	  See Documentation/trace/ftrace-design.rst
+
+config HAVE_FENTRY
+	bool
+	help
+	  Arch supports the gcc options -pg with -mfentry
+
+config HAVE_NOP_MCOUNT
+	bool
+	help
+	  Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount
+
+config HAVE_OBJTOOL_MCOUNT
+	bool
+	help
+	  Arch supports objtool --mcount
+
+config HAVE_C_RECORDMCOUNT
+	bool
+	help
+	  C version of recordmcount available?
+
+config HAVE_BUILDTIME_MCOUNT_SORT
+       bool
+       help
+         An architecture selects this if it sorts the mcount_loc section
+	 at build time.
+
+config BUILDTIME_MCOUNT_SORT
+       bool
+       default y
+       depends on HAVE_BUILDTIME_MCOUNT_SORT && DYNAMIC_FTRACE
+       help
+         Sort the mcount_loc section at build time.
+
+config TRACER_MAX_TRACE
+	bool
+
+config TRACE_CLOCK
+	bool
+
+config RING_BUFFER
+	bool
+	select TRACE_CLOCK
+	select IRQ_WORK
+
+config EVENT_TRACING
+	select CONTEXT_SWITCH_TRACER
+	select GLOB
+	bool
+
+config CONTEXT_SWITCH_TRACER
+	bool
+
+config RING_BUFFER_ALLOW_SWAP
+	bool
+	help
+	 Allow the use of ring_buffer_swap_cpu.
+	 Adds a very slight overhead to tracing when enabled.
+
+config PREEMPTIRQ_TRACEPOINTS
+	bool
+	depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS
+	select TRACING
+	default y
+	help
+	  Create preempt/irq toggle tracepoints if needed, so that other parts
+	  of the kernel can use them to generate or add hooks to them.
+
+# All tracer options should select GENERIC_TRACER. For those options that are
+# enabled by all tracers (context switch and event tracer) they select TRACING.
+# This allows those options to appear when no other tracer is selected. But the
+# options do not appear when something else selects it. We need the two options
+# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
+# hiding of the automatic options.
+
+config TRACING
+	bool
+	select RING_BUFFER
+	select STACKTRACE if STACKTRACE_SUPPORT
+	select TRACEPOINTS
+	select NOP_TRACER
+	select BINARY_PRINTF
+	select EVENT_TRACING
+	select TRACE_CLOCK
+	select TASKS_RCU if PREEMPTION
+
+config GENERIC_TRACER
+	bool
+	select TRACING
+
+#
+# Minimum requirements an architecture has to meet for us to
+# be able to offer generic tracing facilities:
+#
+config TRACING_SUPPORT
+	bool
+	depends on TRACE_IRQFLAGS_SUPPORT
+	depends on STACKTRACE_SUPPORT
+	default y
+
+menuconfig FTRACE
+	bool "Tracers"
+	depends on TRACING_SUPPORT
+	default y if DEBUG_KERNEL
+	help
+	  Enable the kernel tracing infrastructure.
+
+if FTRACE
+
+config BOOTTIME_TRACING
+	bool "Boot-time Tracing support"
+	depends on TRACING
+	select BOOT_CONFIG
+	help
+	  Enable developer to setup ftrace subsystem via supplemental
+	  kernel cmdline at boot time for debugging (tracing) driver
+	  initialization and boot process.
+
+config FUNCTION_TRACER
+	bool "Kernel Function Tracer"
+	depends on HAVE_FUNCTION_TRACER
+	select KALLSYMS
+	select GENERIC_TRACER
+	select CONTEXT_SWITCH_TRACER
+	select GLOB
+	select TASKS_RCU if PREEMPTION
+	select TASKS_RUDE_RCU
+	help
+	  Enable the kernel to trace every kernel function. This is done
+	  by using a compiler feature to insert a small, 5-byte No-Operation
+	  instruction at the beginning of every kernel function, which NOP
+	  sequence is then dynamically patched into a tracer call when
+	  tracing is enabled by the administrator. If it's runtime disabled
+	  (the bootup default), then the overhead of the instructions is very
+	  small and not measurable even in micro-benchmarks (at least on
+	  x86, but may have impact on other architectures).
+
+config FUNCTION_GRAPH_TRACER
+	bool "Kernel Function Graph Tracer"
+	depends on HAVE_FUNCTION_GRAPH_TRACER
+	depends on FUNCTION_TRACER
+	depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
+	default y
+	help
+	  Enable the kernel to trace a function at both its return
+	  and its entry.
+	  Its first purpose is to trace the duration of functions and
+	  draw a call graph for each thread with some information like
+	  the return value. This is done by setting the current return
+	  address on the current task structure into a stack of calls.
+
+config DYNAMIC_FTRACE
+	bool "enable/disable function tracing dynamically"
+	depends on FUNCTION_TRACER
+	depends on HAVE_DYNAMIC_FTRACE
+	default y
+	help
+	  This option will modify all the calls to function tracing
+	  dynamically (will patch them out of the binary image and
+	  replace them with a No-Op instruction) on boot up. During
+	  compile time, a table is made of all the locations that ftrace
+	  can function trace, and this table is linked into the kernel
+	  image. When this is enabled, functions can be individually
+	  enabled, and the functions not enabled will not affect
+	  performance of the system.
+
+	  See the files in /sys/kernel/debug/tracing:
+	    available_filter_functions
+	    set_ftrace_filter
+	    set_ftrace_notrace
+
+	  This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
+	  otherwise has native performance as long as no tracing is active.
+
+config DYNAMIC_FTRACE_WITH_REGS
+	def_bool y
+	depends on DYNAMIC_FTRACE
+	depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
+
+config DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	def_bool y
+	depends on DYNAMIC_FTRACE_WITH_REGS
+	depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+
+config DYNAMIC_FTRACE_WITH_ARGS
+	def_bool y
+	depends on DYNAMIC_FTRACE
+	depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS
+
+config FPROBE
+	bool "Kernel Function Probe (fprobe)"
+	depends on FUNCTION_TRACER
+	depends on DYNAMIC_FTRACE_WITH_REGS
+	depends on HAVE_RETHOOK
+	select RETHOOK
+	default n
+	help
+	  This option enables kernel function probe (fprobe) based on ftrace.
+	  The fprobe is similar to kprobes, but probes only for kernel function
+	  entries and exits. This also can probe multiple functions by one
+	  fprobe.
+
+	  If unsure, say N.
+
+config FUNCTION_PROFILER
+	bool "Kernel function profiler"
+	depends on FUNCTION_TRACER
+	default n
+	help
+	  This option enables the kernel function profiler. A file is created
+	  in debugfs called function_profile_enabled which defaults to zero.
+	  When a 1 is echoed into this file profiling begins, and when a
+	  zero is entered, profiling stops. A "functions" file is created in
+	  the trace_stat directory; this file shows the list of functions that
+	  have been hit and their counters.
+
+	  If in doubt, say N.
+
+config STACK_TRACER
+	bool "Trace max stack"
+	depends on HAVE_FUNCTION_TRACER
+	select FUNCTION_TRACER
+	select STACKTRACE
+	select KALLSYMS
+	help
+	  This special tracer records the maximum stack footprint of the
+	  kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
+
+	  This tracer works by hooking into every function call that the
+	  kernel executes, and keeping a maximum stack depth value and
+	  stack-trace saved.  If this is configured with DYNAMIC_FTRACE
+	  then it will not have any overhead while the stack tracer
+	  is disabled.
+
+	  To enable the stack tracer on bootup, pass in 'stacktrace'
+	  on the kernel command line.
+
+	  The stack tracer can also be enabled or disabled via the
+	  sysctl kernel.stack_tracer_enabled
+
+	  Say N if unsure.
+
+config TRACE_PREEMPT_TOGGLE
+	bool
+	help
+	  Enables hooks which will be called when preemption is first disabled,
+	  and last enabled.
+
+config IRQSOFF_TRACER
+	bool "Interrupts-off Latency Tracer"
+	default n
+	depends on TRACE_IRQFLAGS_SUPPORT
+	select TRACE_IRQFLAGS
+	select GENERIC_TRACER
+	select TRACER_MAX_TRACE
+	select RING_BUFFER_ALLOW_SWAP
+	select TRACER_SNAPSHOT
+	select TRACER_SNAPSHOT_PER_CPU_SWAP
+	help
+	  This option measures the time spent in irqs-off critical
+	  sections, with microsecond accuracy.
+
+	  The default measurement method is a maximum search, which is
+	  disabled by default and can be runtime (re-)started
+	  via:
+
+	      echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
+
+	  (Note that kernel size and overhead increase with this option
+	  enabled. This option and the preempt-off timing option can be
+	  used together or separately.)
+
+config PREEMPT_TRACER
+	bool "Preemption-off Latency Tracer"
+	default n
+	depends on PREEMPTION
+	select GENERIC_TRACER
+	select TRACER_MAX_TRACE
+	select RING_BUFFER_ALLOW_SWAP
+	select TRACER_SNAPSHOT
+	select TRACER_SNAPSHOT_PER_CPU_SWAP
+	select TRACE_PREEMPT_TOGGLE
+	help
+	  This option measures the time spent in preemption-off critical
+	  sections, with microsecond accuracy.
+
+	  The default measurement method is a maximum search, which is
+	  disabled by default and can be runtime (re-)started
+	  via:
+
+	      echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
+
+	  (Note that kernel size and overhead increase with this option
+	  enabled. This option and the irqs-off timing option can be
+	  used together or separately.)
+
+config SCHED_TRACER
+	bool "Scheduling Latency Tracer"
+	select GENERIC_TRACER
+	select CONTEXT_SWITCH_TRACER
+	select TRACER_MAX_TRACE
+	select TRACER_SNAPSHOT
+	help
+	  This tracer tracks the latency of the highest priority task
+	  to be scheduled in, starting from the point it has woken up.
+
+config HWLAT_TRACER
+	bool "Tracer to detect hardware latencies (like SMIs)"
+	select GENERIC_TRACER
+	select TRACER_MAX_TRACE
+	help
+	 This tracer, when enabled will create one or more kernel threads,
+	 depending on what the cpumask file is set to, which each thread
+	 spinning in a loop looking for interruptions caused by
+	 something other than the kernel. For example, if a
+	 System Management Interrupt (SMI) takes a noticeable amount of
+	 time, this tracer will detect it. This is useful for testing
+	 if a system is reliable for Real Time tasks.
+
+	 Some files are created in the tracing directory when this
+	 is enabled:
+
+	   hwlat_detector/width   - time in usecs for how long to spin for
+	   hwlat_detector/window  - time in usecs between the start of each
+				     iteration
+
+	 A kernel thread is created that will spin with interrupts disabled
+	 for "width" microseconds in every "window" cycle. It will not spin
+	 for "window - width" microseconds, where the system can
+	 continue to operate.
+
+	 The output will appear in the trace and trace_pipe files.
+
+	 When the tracer is not running, it has no affect on the system,
+	 but when it is running, it can cause the system to be
+	 periodically non responsive. Do not run this tracer on a
+	 production system.
+
+	 To enable this tracer, echo in "hwlat" into the current_tracer
+	 file. Every time a latency is greater than tracing_thresh, it will
+	 be recorded into the ring buffer.
+
+config OSNOISE_TRACER
+	bool "OS Noise tracer"
+	select GENERIC_TRACER
+	select TRACER_MAX_TRACE
+	help
+	  In the context of high-performance computing (HPC), the Operating
+	  System Noise (osnoise) refers to the interference experienced by an
+	  application due to activities inside the operating system. In the
+	  context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread
+	  can cause noise to the system. Moreover, hardware-related jobs can
+	  also cause noise, for example, via SMIs.
+
+	  The osnoise tracer leverages the hwlat_detector by running a similar
+	  loop with preemption, SoftIRQs and IRQs enabled, thus allowing all
+	  the sources of osnoise during its execution. The osnoise tracer takes
+	  note of the entry and exit point of any source of interferences,
+	  increasing a per-cpu interference counter. It saves an interference
+	  counter for each source of interference. The interference counter for
+	  NMI, IRQs, SoftIRQs, and threads is increased anytime the tool
+	  observes these interferences' entry events. When a noise happens
+	  without any interference from the operating system level, the
+	  hardware noise counter increases, pointing to a hardware-related
+	  noise. In this way, osnoise can account for any source of
+	  interference. At the end of the period, the osnoise tracer prints
+	  the sum of all noise, the max single noise, the percentage of CPU
+	  available for the thread, and the counters for the noise sources.
+
+	  In addition to the tracer, a set of tracepoints were added to
+	  facilitate the identification of the osnoise source.
+
+	  The output will appear in the trace and trace_pipe files.
+
+	  To enable this tracer, echo in "osnoise" into the current_tracer
+          file.
+
+config TIMERLAT_TRACER
+	bool "Timerlat tracer"
+	select OSNOISE_TRACER
+	select GENERIC_TRACER
+	help
+	  The timerlat tracer aims to help the preemptive kernel developers
+	  to find sources of wakeup latencies of real-time threads.
+
+	  The tracer creates a per-cpu kernel thread with real-time priority.
+	  The tracer thread sets a periodic timer to wakeup itself, and goes
+	  to sleep waiting for the timer to fire. At the wakeup, the thread
+	  then computes a wakeup latency value as the difference between
+	  the current time and the absolute time that the timer was set
+	  to expire.
+
+	  The tracer prints two lines at every activation. The first is the
+	  timer latency observed at the hardirq context before the
+	  activation of the thread. The second is the timer latency observed
+	  by the thread, which is the same level that cyclictest reports. The
+	  ACTIVATION ID field serves to relate the irq execution to its
+	  respective thread execution.
+
+	  The tracer is build on top of osnoise tracer, and the osnoise:
+	  events can be used to trace the source of interference from NMI,
+	  IRQs and other threads. It also enables the capture of the
+	  stacktrace at the IRQ context, which helps to identify the code
+	  path that can cause thread delay.
+
+config MMIOTRACE
+	bool "Memory mapped IO tracing"
+	depends on HAVE_MMIOTRACE_SUPPORT && PCI
+	select GENERIC_TRACER
+	help
+	  Mmiotrace traces Memory Mapped I/O access and is meant for
+	  debugging and reverse engineering. It is called from the ioremap
+	  implementation and works via page faults. Tracing is disabled by
+	  default and can be enabled at run-time.
+
+	  See Documentation/trace/mmiotrace.rst.
+	  If you are not helping to develop drivers, say N.
+
+config ENABLE_DEFAULT_TRACERS
+	bool "Trace process context switches and events"
+	depends on !GENERIC_TRACER
+	select TRACING
+	help
+	  This tracer hooks to various trace points in the kernel,
+	  allowing the user to pick and choose which trace point they
+	  want to trace. It also includes the sched_switch tracer plugin.
+
+config FTRACE_SYSCALLS
+	bool "Trace syscalls"
+	depends on HAVE_SYSCALL_TRACEPOINTS
+	select GENERIC_TRACER
+	select KALLSYMS
+	help
+	  Basic tracer to catch the syscall entry and exit events.
+
+config TRACER_SNAPSHOT
+	bool "Create a snapshot trace buffer"
+	select TRACER_MAX_TRACE
+	help
+	  Allow tracing users to take snapshot of the current buffer using the
+	  ftrace interface, e.g.:
+
+	      echo 1 > /sys/kernel/debug/tracing/snapshot
+	      cat snapshot
+
+config TRACER_SNAPSHOT_PER_CPU_SWAP
+	bool "Allow snapshot to swap per CPU"
+	depends on TRACER_SNAPSHOT
+	select RING_BUFFER_ALLOW_SWAP
+	help
+	  Allow doing a snapshot of a single CPU buffer instead of a
+	  full swap (all buffers). If this is set, then the following is
+	  allowed:
+
+	      echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
+
+	  After which, only the tracing buffer for CPU 2 was swapped with
+	  the main tracing buffer, and the other CPU buffers remain the same.
+
+	  When this is enabled, this adds a little more overhead to the
+	  trace recording, as it needs to add some checks to synchronize
+	  recording with swaps. But this does not affect the performance
+	  of the overall system. This is enabled by default when the preempt
+	  or irq latency tracers are enabled, as those need to swap as well
+	  and already adds the overhead (plus a lot more).
+
+config TRACE_BRANCH_PROFILING
+	bool
+	select GENERIC_TRACER
+
+choice
+	prompt "Branch Profiling"
+	default BRANCH_PROFILE_NONE
+	help
+	 The branch profiling is a software profiler. It will add hooks
+	 into the C conditionals to test which path a branch takes.
+
+	 The likely/unlikely profiler only looks at the conditions that
+	 are annotated with a likely or unlikely macro.
+
+	 The "all branch" profiler will profile every if-statement in the
+	 kernel. This profiler will also enable the likely/unlikely
+	 profiler.
+
+	 Either of the above profilers adds a bit of overhead to the system.
+	 If unsure, choose "No branch profiling".
+
+config BRANCH_PROFILE_NONE
+	bool "No branch profiling"
+	help
+	  No branch profiling. Branch profiling adds a bit of overhead.
+	  Only enable it if you want to analyse the branching behavior.
+	  Otherwise keep it disabled.
+
+config PROFILE_ANNOTATED_BRANCHES
+	bool "Trace likely/unlikely profiler"
+	select TRACE_BRANCH_PROFILING
+	help
+	  This tracer profiles all likely and unlikely macros
+	  in the kernel. It will display the results in:
+
+	  /sys/kernel/debug/tracing/trace_stat/branch_annotated
+
+	  Note: this will add a significant overhead; only turn this
+	  on if you need to profile the system's use of these macros.
+
+config PROFILE_ALL_BRANCHES
+	bool "Profile all if conditionals" if !FORTIFY_SOURCE
+	select TRACE_BRANCH_PROFILING
+	help
+	  This tracer profiles all branch conditions. Every if ()
+	  taken in the kernel is recorded whether it hit or miss.
+	  The results will be displayed in:
+
+	  /sys/kernel/debug/tracing/trace_stat/branch_all
+
+	  This option also enables the likely/unlikely profiler.
+
+	  This configuration, when enabled, will impose a great overhead
+	  on the system. This should only be enabled when the system
+	  is to be analyzed in much detail.
+endchoice
+
+config TRACING_BRANCHES
+	bool
+	help
+	  Selected by tracers that will trace the likely and unlikely
+	  conditions. This prevents the tracers themselves from being
+	  profiled. Profiling the tracing infrastructure can only happen
+	  when the likelys and unlikelys are not being traced.
+
+config BRANCH_TRACER
+	bool "Trace likely/unlikely instances"
+	depends on TRACE_BRANCH_PROFILING
+	select TRACING_BRANCHES
+	help
+	  This traces the events of likely and unlikely condition
+	  calls in the kernel.  The difference between this and the
+	  "Trace likely/unlikely profiler" is that this is not a
+	  histogram of the callers, but actually places the calling
+	  events into a running trace buffer to see when and where the
+	  events happened, as well as their results.
+
+	  Say N if unsure.
+
+config BLK_DEV_IO_TRACE
+	bool "Support for tracing block IO actions"
+	depends on SYSFS
+	depends on BLOCK
+	select RELAY
+	select DEBUG_FS
+	select TRACEPOINTS
+	select GENERIC_TRACER
+	select STACKTRACE
+	help
+	  Say Y here if you want to be able to trace the block layer actions
+	  on a given queue. Tracing allows you to see any traffic happening
+	  on a block device queue. For more information (and the userspace
+	  support tools needed), fetch the blktrace tools from:
+
+	  git://git.kernel.dk/blktrace.git
+
+	  Tracing also is possible using the ftrace interface, e.g.:
+
+	    echo 1 > /sys/block/sda/sda1/trace/enable
+	    echo blk > /sys/kernel/debug/tracing/current_tracer
+	    cat /sys/kernel/debug/tracing/trace_pipe
+
+	  If unsure, say N.
+
+config KPROBE_EVENTS
+	depends on KPROBES
+	depends on HAVE_REGS_AND_STACK_ACCESS_API
+	bool "Enable kprobes-based dynamic events"
+	select TRACING
+	select PROBE_EVENTS
+	select DYNAMIC_EVENTS
+	default y
+	help
+	  This allows the user to add tracing events (similar to tracepoints)
+	  on the fly via the ftrace interface. See
+	  Documentation/trace/kprobetrace.rst for more details.
+
+	  Those events can be inserted wherever kprobes can probe, and record
+	  various register and memory values.
+
+	  This option is also required by perf-probe subcommand of perf tools.
+	  If you want to use perf tools, this option is strongly recommended.
+
+config KPROBE_EVENTS_ON_NOTRACE
+	bool "Do NOT protect notrace function from kprobe events"
+	depends on KPROBE_EVENTS
+	depends on DYNAMIC_FTRACE
+	default n
+	help
+	  This is only for the developers who want to debug ftrace itself
+	  using kprobe events.
+
+	  If kprobes can use ftrace instead of breakpoint, ftrace related
+	  functions are protected from kprobe-events to prevent an infinite
+	  recursion or any unexpected execution path which leads to a kernel
+	  crash.
+
+	  This option disables such protection and allows you to put kprobe
+	  events on ftrace functions for debugging ftrace by itself.
+	  Note that this might let you shoot yourself in the foot.
+
+	  If unsure, say N.
+
+config UPROBE_EVENTS
+	bool "Enable uprobes-based dynamic events"
+	depends on ARCH_SUPPORTS_UPROBES
+	depends on MMU
+	depends on PERF_EVENTS
+	select UPROBES
+	select PROBE_EVENTS
+	select DYNAMIC_EVENTS
+	select TRACING
+	default y
+	help
+	  This allows the user to add tracing events on top of userspace
+	  dynamic events (similar to tracepoints) on the fly via the trace
+	  events interface. Those events can be inserted wherever uprobes
+	  can probe, and record various registers.
+	  This option is required if you plan to use perf-probe subcommand
+	  of perf tools on user space applications.
+
+config BPF_EVENTS
+	depends on BPF_SYSCALL
+	depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS
+	bool
+	default y
+	help
+	  This allows the user to attach BPF programs to kprobe, uprobe, and
+	  tracepoint events.
+
+config DYNAMIC_EVENTS
+	def_bool n
+
+config PROBE_EVENTS
+	def_bool n
+
+config BPF_KPROBE_OVERRIDE
+	bool "Enable BPF programs to override a kprobed function"
+	depends on BPF_EVENTS
+	depends on FUNCTION_ERROR_INJECTION
+	default n
+	help
+	 Allows BPF to override the execution of a probed function and
+	 set a different return value.  This is used for error injection.
+
+config FTRACE_MCOUNT_RECORD
+	def_bool y
+	depends on DYNAMIC_FTRACE
+	depends on HAVE_FTRACE_MCOUNT_RECORD
+
+config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
+	bool
+	depends on FTRACE_MCOUNT_RECORD
+
+config FTRACE_MCOUNT_USE_CC
+	def_bool y
+	depends on $(cc-option,-mrecord-mcount)
+	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
+	depends on FTRACE_MCOUNT_RECORD
+
+config FTRACE_MCOUNT_USE_OBJTOOL
+	def_bool y
+	depends on HAVE_OBJTOOL_MCOUNT
+	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
+	depends on !FTRACE_MCOUNT_USE_CC
+	depends on FTRACE_MCOUNT_RECORD
+	select OBJTOOL
+
+config FTRACE_MCOUNT_USE_RECORDMCOUNT
+	def_bool y
+	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
+	depends on !FTRACE_MCOUNT_USE_CC
+	depends on !FTRACE_MCOUNT_USE_OBJTOOL
+	depends on FTRACE_MCOUNT_RECORD
+
+config TRACING_MAP
+	bool
+	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
+	help
+	  tracing_map is a special-purpose lock-free map for tracing,
+	  separated out as a stand-alone facility in order to allow it
+	  to be shared between multiple tracers.  It isn't meant to be
+	  generally used outside of that context, and is normally
+	  selected by tracers that use it.
+
+config SYNTH_EVENTS
+	bool "Synthetic trace events"
+	select TRACING
+	select DYNAMIC_EVENTS
+	default n
+	help
+	  Synthetic events are user-defined trace events that can be
+	  used to combine data from other trace events or in fact any
+	  data source.  Synthetic events can be generated indirectly
+	  via the trace() action of histogram triggers or directly
+	  by way of an in-kernel API.
+
+	  See Documentation/trace/events.rst or
+	  Documentation/trace/histogram.rst for details and examples.
+
+	  If in doubt, say N.
+
+config USER_EVENTS
+	bool "User trace events"
+	select TRACING
+	select DYNAMIC_EVENTS
+	depends on BROKEN || COMPILE_TEST # API needs to be straighten out
+	help
+	  User trace events are user-defined trace events that
+	  can be used like an existing kernel trace event.  User trace
+	  events are generated by writing to a tracefs file.  User
+	  processes can determine if their tracing events should be
+	  generated by memory mapping a tracefs file and checking for
+	  an associated byte being non-zero.
+
+	  If in doubt, say N.
+
+config HIST_TRIGGERS
+	bool "Histogram triggers"
+	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
+	select TRACING_MAP
+	select TRACING
+	select DYNAMIC_EVENTS
+	select SYNTH_EVENTS
+	default n
+	help
+	  Hist triggers allow one or more arbitrary trace event fields
+	  to be aggregated into hash tables and dumped to stdout by
+	  reading a debugfs/tracefs file.  They're useful for
+	  gathering quick and dirty (though precise) summaries of
+	  event activity as an initial guide for further investigation
+	  using more advanced tools.
+
+	  Inter-event tracing of quantities such as latencies is also
+	  supported using hist triggers under this option.
+
+	  See Documentation/trace/histogram.rst.
+	  If in doubt, say N.
+
+config TRACE_EVENT_INJECT
+	bool "Trace event injection"
+	depends on TRACING
+	help
+	  Allow user-space to inject a specific trace event into the ring
+	  buffer. This is mainly used for testing purpose.
+
+	  If unsure, say N.
+
+config TRACEPOINT_BENCHMARK
+	bool "Add tracepoint that benchmarks tracepoints"
+	help
+	 This option creates the tracepoint "benchmark:benchmark_event".
+	 When the tracepoint is enabled, it kicks off a kernel thread that
+	 goes into an infinite loop (calling cond_resched() to let other tasks
+	 run), and calls the tracepoint. Each iteration will record the time
+	 it took to write to the tracepoint and the next iteration that
+	 data will be passed to the tracepoint itself. That is, the tracepoint
+	 will report the time it took to do the previous tracepoint.
+	 The string written to the tracepoint is a static string of 128 bytes
+	 to keep the time the same. The initial string is simply a write of
+	 "START". The second string records the cold cache time of the first
+	 write which is not added to the rest of the calculations.
+
+	 As it is a tight loop, it benchmarks as hot cache. That's fine because
+	 we care most about hot paths that are probably in cache already.
+
+	 An example of the output:
+
+	      START
+	      first=3672 [COLD CACHED]
+	      last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
+	      last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
+	      last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
+	      last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
+	      last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
+	      last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
+
+
+config RING_BUFFER_BENCHMARK
+	tristate "Ring buffer benchmark stress tester"
+	depends on RING_BUFFER
+	help
+	  This option creates a test to stress the ring buffer and benchmark it.
+	  It creates its own ring buffer such that it will not interfere with
+	  any other users of the ring buffer (such as ftrace). It then creates
+	  a producer and consumer that will run for 10 seconds and sleep for
+	  10 seconds. Each interval it will print out the number of events
+	  it recorded and give a rough estimate of how long each iteration took.
+
+	  It does not disable interrupts or raise its priority, so it may be
+	  affected by processes that are running.
+
+	  If unsure, say N.
+
+config TRACE_EVAL_MAP_FILE
+       bool "Show eval mappings for trace events"
+       depends on TRACING
+       help
+	The "print fmt" of the trace events will show the enum/sizeof names
+	instead of their values. This can cause problems for user space tools
+	that use this string to parse the raw data as user space does not know
+	how to convert the string to its value.
+
+	To fix this, there's a special macro in the kernel that can be used
+	to convert an enum/sizeof into its value. If this macro is used, then
+	the print fmt strings will be converted to their values.
+
+	If something does not get converted properly, this option can be
+	used to show what enums/sizeof the kernel tried to convert.
+
+	This option is for debugging the conversions. A file is created
+	in the tracing directory called "eval_map" that will show the
+	names matched with their values and what trace event system they
+	belong too.
+
+	Normally, the mapping of the strings to values will be freed after
+	boot up or module load. With this option, they will not be freed, as
+	they are needed for the "eval_map" file. Enabling this option will
+	increase the memory footprint of the running kernel.
+
+	If unsure, say N.
+
+config FTRACE_RECORD_RECURSION
+	bool "Record functions that recurse in function tracing"
+	depends on FUNCTION_TRACER
+	help
+	  All callbacks that attach to the function tracing have some sort
+	  of protection against recursion. Even though the protection exists,
+	  it adds overhead. This option will create a file in the tracefs
+	  file system called "recursed_functions" that will list the functions
+	  that triggered a recursion.
+
+	  This will add more overhead to cases that have recursion.
+
+	  If unsure, say N
+
+config FTRACE_RECORD_RECURSION_SIZE
+	int "Max number of recursed functions to record"
+	default	128
+	depends on FTRACE_RECORD_RECURSION
+	help
+	  This defines the limit of number of functions that can be
+	  listed in the "recursed_functions" file, that lists all
+	  the functions that caused a recursion to happen.
+	  This file can be reset, but the limit can not change in
+	  size at runtime.
+
+config RING_BUFFER_RECORD_RECURSION
+	bool "Record functions that recurse in the ring buffer"
+	depends on FTRACE_RECORD_RECURSION
+	# default y, because it is coupled with FTRACE_RECORD_RECURSION
+	default y
+	help
+	  The ring buffer has its own internal recursion. Although when
+	  recursion happens it wont cause harm because of the protection,
+	  but it does cause an unwanted overhead. Enabling this option will
+	  place where recursion was detected into the ftrace "recursed_functions"
+	  file.
+
+	  This will add more overhead to cases that have recursion.
+
+config GCOV_PROFILE_FTRACE
+	bool "Enable GCOV profiling on ftrace subsystem"
+	depends on GCOV_KERNEL
+	help
+	  Enable GCOV profiling on ftrace subsystem for checking
+	  which functions/lines are tested.
+
+	  If unsure, say N.
+
+	  Note that on a kernel compiled with this config, ftrace will
+	  run significantly slower.
+
+config FTRACE_SELFTEST
+	bool
+
+config FTRACE_STARTUP_TEST
+	bool "Perform a startup test on ftrace"
+	depends on GENERIC_TRACER
+	select FTRACE_SELFTEST
+	help
+	  This option performs a series of startup tests on ftrace. On bootup
+	  a series of tests are made to verify that the tracer is
+	  functioning properly. It will do tests on all the configured
+	  tracers of ftrace.
+
+config EVENT_TRACE_STARTUP_TEST
+	bool "Run selftest on trace events"
+	depends on FTRACE_STARTUP_TEST
+	default y
+	help
+	  This option performs a test on all trace events in the system.
+	  It basically just enables each event and runs some code that
+	  will trigger events (not necessarily the event it enables)
+	  This may take some time run as there are a lot of events.
+
+config EVENT_TRACE_TEST_SYSCALLS
+	bool "Run selftest on syscall events"
+	depends on EVENT_TRACE_STARTUP_TEST
+	help
+	 This option will also enable testing every syscall event.
+	 It only enables the event and disables it and runs various loads
+	 with the event enabled. This adds a bit more time for kernel boot
+	 up since it runs this on every system call defined.
+
+	 TBD - enable a way to actually call the syscalls as we test their
+	       events
+
+config FTRACE_SORT_STARTUP_TEST
+       bool "Verify compile time sorting of ftrace functions"
+       depends on DYNAMIC_FTRACE
+       depends on BUILDTIME_MCOUNT_SORT
+       help
+	 Sorting of the mcount_loc sections that is used to find the
+	 where the ftrace knows where to patch functions for tracing
+	 and other callbacks is done at compile time. But if the sort
+	 is not done correctly, it will cause non-deterministic failures.
+	 When this is set, the sorted sections will be verified that they
+	 are in deed sorted and will warn if they are not.
+
+	 If unsure, say N
+
+config RING_BUFFER_STARTUP_TEST
+       bool "Ring buffer startup self test"
+       depends on RING_BUFFER
+       help
+	 Run a simple self test on the ring buffer on boot up. Late in the
+	 kernel boot sequence, the test will start that kicks off
+	 a thread per cpu. Each thread will write various size events
+	 into the ring buffer. Another thread is created to send IPIs
+	 to each of the threads, where the IPI handler will also write
+	 to the ring buffer, to test/stress the nesting ability.
+	 If any anomalies are discovered, a warning will be displayed
+	 and all ring buffers will be disabled.
+
+	 The test runs for 10 seconds. This will slow your boot time
+	 by at least 10 more seconds.
+
+	 At the end of the test, statics and more checks are done.
+	 It will output the stats of each per cpu buffer. What
+	 was written, the sizes, what was read, what was lost, and
+	 other similar details.
+
+	 If unsure, say N
+
+config RING_BUFFER_VALIDATE_TIME_DELTAS
+	bool "Verify ring buffer time stamp deltas"
+	depends on RING_BUFFER
+	help
+	  This will audit the time stamps on the ring buffer sub
+	  buffer to make sure that all the time deltas for the
+	  events on a sub buffer matches the current time stamp.
+	  This audit is performed for every event that is not
+	  interrupted, or interrupting another event. A check
+	  is also made when traversing sub buffers to make sure
+	  that all the deltas on the previous sub buffer do not
+	  add up to be greater than the current time stamp.
+
+	  NOTE: This adds significant overhead to recording of events,
+	  and should only be used to test the logic of the ring buffer.
+	  Do not use it on production systems.
+
+	  Only say Y if you understand what this does, and you
+	  still want it enabled. Otherwise say N
+
+config MMIOTRACE_TEST
+	tristate "Test module for mmiotrace"
+	depends on MMIOTRACE && m
+	help
+	  This is a dumb module for testing mmiotrace. It is very dangerous
+	  as it will write garbage to IO memory starting at a given address.
+	  However, it should be safe to use on e.g. unused portion of VRAM.
+
+	  Say N, unless you absolutely know what you are doing.
+
+config PREEMPTIRQ_DELAY_TEST
+	tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers"
+	depends on m
+	help
+	  Select this option to build a test module that can help test latency
+	  tracers by executing a preempt or irq disable section with a user
+	  configurable delay. The module busy waits for the duration of the
+	  critical section.
+
+	  For example, the following invocation generates a burst of three
+	  irq-disabled critical sections for 500us:
+	  modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3
+
+	  What's more, if you want to attach the test on the cpu which the latency
+	  tracer is running on, specify cpu_affinity=cpu_num at the end of the
+	  command.
+
+	  If unsure, say N
+
+config SYNTH_EVENT_GEN_TEST
+	tristate "Test module for in-kernel synthetic event generation"
+	depends on SYNTH_EVENTS
+	help
+          This option creates a test module to check the base
+          functionality of in-kernel synthetic event definition and
+          generation.
+
+          To test, insert the module, and then check the trace buffer
+	  for the generated sample events.
+
+	  If unsure, say N.
+
+config KPROBE_EVENT_GEN_TEST
+	tristate "Test module for in-kernel kprobe event generation"
+	depends on KPROBE_EVENTS
+	help
+          This option creates a test module to check the base
+          functionality of in-kernel kprobe event definition.
+
+          To test, insert the module, and then check the trace buffer
+	  for the generated kprobe events.
+
+	  If unsure, say N.
+
+config HIST_TRIGGERS_DEBUG
+	bool "Hist trigger debug support"
+	depends on HIST_TRIGGERS
+	help
+          Add "hist_debug" file for each event, which when read will
+          dump out a bunch of internal details about the hist triggers
+          defined on that event.
+
+          The hist_debug file serves a couple of purposes:
+
+            - Helps developers verify that nothing is broken.
+
+            - Provides educational information to support the details
+              of the hist trigger internals as described by
+              Documentation/trace/histogram-design.rst.
+
+          The hist_debug output only covers the data structures
+          related to the histogram definitions themselves and doesn't
+          display the internals of map buckets or variable values of
+          running histograms.
+
+          If unsure, say N.
+
+source "kernel/trace/rv/Kconfig"
+
+endif # FTRACE
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
new file mode 100644
index 000000000..c6651e16b
--- /dev/null
+++ b/kernel/trace/Makefile
@@ -0,0 +1,111 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# Do not instrument the tracer itself:
+
+ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE)
+
+ifdef CONFIG_FUNCTION_TRACER
+
+# Avoid recursion due to instrumentation.
+KCSAN_SANITIZE := n
+
+ifdef CONFIG_FTRACE_SELFTEST
+# selftest needs instrumentation
+CFLAGS_trace_selftest_dynamic.o = $(CC_FLAGS_FTRACE)
+obj-y += trace_selftest_dynamic.o
+endif
+endif
+
+ifdef CONFIG_FTRACE_STARTUP_TEST
+CFLAGS_trace_kprobe_selftest.o = $(CC_FLAGS_FTRACE)
+obj-$(CONFIG_KPROBE_EVENTS) += trace_kprobe_selftest.o
+endif
+
+# If unlikely tracing is enabled, do not trace these files
+ifdef CONFIG_TRACING_BRANCHES
+KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
+endif
+
+# for GCOV coverage profiling
+ifdef CONFIG_GCOV_PROFILE_FTRACE
+GCOV_PROFILE := y
+endif
+
+# Functions in this file could be invoked from early interrupt
+# code and produce random code coverage.
+KCOV_INSTRUMENT_trace_preemptirq.o := n
+
+CFLAGS_bpf_trace.o := -I$(src)
+
+CFLAGS_trace_benchmark.o := -I$(src)
+CFLAGS_trace_events_filter.o := -I$(src)
+
+obj-$(CONFIG_TRACE_CLOCK) += trace_clock.o
+
+obj-$(CONFIG_FUNCTION_TRACER) += libftrace.o
+obj-$(CONFIG_RING_BUFFER) += ring_buffer.o
+obj-$(CONFIG_RING_BUFFER_BENCHMARK) += ring_buffer_benchmark.o
+
+obj-$(CONFIG_TRACING) += trace.o
+obj-$(CONFIG_TRACING) += trace_output.o
+obj-$(CONFIG_TRACING) += trace_seq.o
+obj-$(CONFIG_TRACING) += trace_stat.o
+obj-$(CONFIG_TRACING) += trace_printk.o
+obj-$(CONFIG_TRACING) += 	pid_list.o
+obj-$(CONFIG_TRACING_MAP) += tracing_map.o
+obj-$(CONFIG_PREEMPTIRQ_DELAY_TEST) += preemptirq_delay_test.o
+obj-$(CONFIG_SYNTH_EVENT_GEN_TEST) += synth_event_gen_test.o
+obj-$(CONFIG_KPROBE_EVENT_GEN_TEST) += kprobe_event_gen_test.o
+obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
+obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
+obj-$(CONFIG_PREEMPTIRQ_TRACEPOINTS) += trace_preemptirq.o
+obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
+obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
+obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o
+obj-$(CONFIG_HWLAT_TRACER) += trace_hwlat.o
+obj-$(CONFIG_OSNOISE_TRACER) += trace_osnoise.o
+obj-$(CONFIG_NOP_TRACER) += trace_nop.o
+obj-$(CONFIG_STACK_TRACER) += trace_stack.o
+obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o
+obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += trace_functions_graph.o
+obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_branch.o
+obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o
+obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += fgraph.o
+ifeq ($(CONFIG_BLOCK),y)
+obj-$(CONFIG_EVENT_TRACING) += blktrace.o
+endif
+obj-$(CONFIG_EVENT_TRACING) += trace_events.o
+obj-$(CONFIG_EVENT_TRACING) += trace_export.o
+obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o
+ifeq ($(CONFIG_PERF_EVENTS),y)
+obj-$(CONFIG_EVENT_TRACING) += trace_event_perf.o
+endif
+obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o
+obj-$(CONFIG_EVENT_TRACING) += trace_events_trigger.o
+obj-$(CONFIG_PROBE_EVENTS) += trace_eprobe.o
+obj-$(CONFIG_TRACE_EVENT_INJECT) += trace_events_inject.o
+obj-$(CONFIG_SYNTH_EVENTS) += trace_events_synth.o
+obj-$(CONFIG_HIST_TRIGGERS) += trace_events_hist.o
+obj-$(CONFIG_USER_EVENTS) += trace_events_user.o
+obj-$(CONFIG_BPF_EVENTS) += bpf_trace.o
+obj-$(CONFIG_KPROBE_EVENTS) += trace_kprobe.o
+obj-$(CONFIG_TRACEPOINTS) += error_report-traces.o
+obj-$(CONFIG_TRACEPOINTS) += power-traces.o
+ifeq ($(CONFIG_PM),y)
+obj-$(CONFIG_TRACEPOINTS) += rpm-traces.o
+endif
+ifeq ($(CONFIG_TRACING),y)
+obj-$(CONFIG_KGDB_KDB) += trace_kdb.o
+endif
+obj-$(CONFIG_DYNAMIC_EVENTS) += trace_dynevent.o
+obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o
+obj-$(CONFIG_UPROBE_EVENTS) += trace_uprobe.o
+obj-$(CONFIG_BOOTTIME_TRACING) += trace_boot.o
+obj-$(CONFIG_FTRACE_RECORD_RECURSION) += trace_recursion_record.o
+obj-$(CONFIG_FPROBE) += fprobe.o
+obj-$(CONFIG_RETHOOK) += rethook.o
+
+obj-$(CONFIG_TRACEPOINT_BENCHMARK) += trace_benchmark.o
+obj-$(CONFIG_RV) += rv/
+
+libftrace-y := ftrace.o
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
new file mode 100644
index 000000000..a5b35bcfb
--- /dev/null
+++ b/kernel/trace/blktrace.c
@@ -0,0 +1,1922 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/blkdev.h>
+#include <linux/blktrace_api.h>
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/debugfs.h>
+#include <linux/export.h>
+#include <linux/time.h>
+#include <linux/uaccess.h>
+#include <linux/list.h>
+#include <linux/blk-cgroup.h>
+
+#include "../../block/blk.h"
+
+#include <trace/events/block.h>
+
+#include "trace_output.h"
+
+#ifdef CONFIG_BLK_DEV_IO_TRACE
+
+static unsigned int blktrace_seq __read_mostly = 1;
+
+static struct trace_array *blk_tr;
+static bool blk_tracer_enabled __read_mostly;
+
+static LIST_HEAD(running_trace_list);
+static __cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(running_trace_lock);
+
+/* Select an alternative, minimalistic output than the original one */
+#define TRACE_BLK_OPT_CLASSIC	0x1
+#define TRACE_BLK_OPT_CGROUP	0x2
+#define TRACE_BLK_OPT_CGNAME	0x4
+
+static struct tracer_opt blk_tracer_opts[] = {
+	/* Default disable the minimalistic output */
+	{ TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
+#ifdef CONFIG_BLK_CGROUP
+	{ TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
+	{ TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
+#endif
+	{ }
+};
+
+static struct tracer_flags blk_tracer_flags = {
+	.val  = 0,
+	.opts = blk_tracer_opts,
+};
+
+/* Global reference count of probes */
+static DEFINE_MUTEX(blk_probe_mutex);
+static int blk_probes_ref;
+
+static void blk_register_tracepoints(void);
+static void blk_unregister_tracepoints(void);
+
+/*
+ * Send out a notify message.
+ */
+static void trace_note(struct blk_trace *bt, pid_t pid, int action,
+		       const void *data, size_t len, u64 cgid)
+{
+	struct blk_io_trace *t;
+	struct ring_buffer_event *event = NULL;
+	struct trace_buffer *buffer = NULL;
+	unsigned int trace_ctx = 0;
+	int cpu = smp_processor_id();
+	bool blk_tracer = blk_tracer_enabled;
+	ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
+
+	if (blk_tracer) {
+		buffer = blk_tr->array_buffer.buffer;
+		trace_ctx = tracing_gen_ctx_flags(0);
+		event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
+						  sizeof(*t) + len + cgid_len,
+						  trace_ctx);
+		if (!event)
+			return;
+		t = ring_buffer_event_data(event);
+		goto record_it;
+	}
+
+	if (!bt->rchan)
+		return;
+
+	t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len);
+	if (t) {
+		t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
+		t->time = ktime_to_ns(ktime_get());
+record_it:
+		t->device = bt->dev;
+		t->action = action | (cgid ? __BLK_TN_CGROUP : 0);
+		t->pid = pid;
+		t->cpu = cpu;
+		t->pdu_len = len + cgid_len;
+		if (cgid_len)
+			memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
+		memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
+
+		if (blk_tracer)
+			trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
+	}
+}
+
+/*
+ * Send out a notify for this process, if we haven't done so since a trace
+ * started
+ */
+static void trace_note_tsk(struct task_struct *tsk)
+{
+	unsigned long flags;
+	struct blk_trace *bt;
+
+	tsk->btrace_seq = blktrace_seq;
+	raw_spin_lock_irqsave(&running_trace_lock, flags);
+	list_for_each_entry(bt, &running_trace_list, running_list) {
+		trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
+			   sizeof(tsk->comm), 0);
+	}
+	raw_spin_unlock_irqrestore(&running_trace_lock, flags);
+}
+
+static void trace_note_time(struct blk_trace *bt)
+{
+	struct timespec64 now;
+	unsigned long flags;
+	u32 words[2];
+
+	/* need to check user space to see if this breaks in y2038 or y2106 */
+	ktime_get_real_ts64(&now);
+	words[0] = (u32)now.tv_sec;
+	words[1] = now.tv_nsec;
+
+	local_irq_save(flags);
+	trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), 0);
+	local_irq_restore(flags);
+}
+
+void __blk_trace_note_message(struct blk_trace *bt,
+		struct cgroup_subsys_state *css, const char *fmt, ...)
+{
+	int n;
+	va_list args;
+	unsigned long flags;
+	char *buf;
+	u64 cgid = 0;
+
+	if (unlikely(bt->trace_state != Blktrace_running &&
+		     !blk_tracer_enabled))
+		return;
+
+	/*
+	 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
+	 * message to the trace.
+	 */
+	if (!(bt->act_mask & BLK_TC_NOTIFY))
+		return;
+
+	local_irq_save(flags);
+	buf = this_cpu_ptr(bt->msg_data);
+	va_start(args, fmt);
+	n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
+	va_end(args);
+
+#ifdef CONFIG_BLK_CGROUP
+	if (css && (blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
+		cgid = cgroup_id(css->cgroup);
+	else
+		cgid = 1;
+#endif
+	trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n, cgid);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(__blk_trace_note_message);
+
+static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
+			 pid_t pid)
+{
+	if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
+		return 1;
+	if (sector && (sector < bt->start_lba || sector > bt->end_lba))
+		return 1;
+	if (bt->pid && pid != bt->pid)
+		return 1;
+
+	return 0;
+}
+
+/*
+ * Data direction bit lookup
+ */
+static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
+				 BLK_TC_ACT(BLK_TC_WRITE) };
+
+#define BLK_TC_RAHEAD		BLK_TC_AHEAD
+#define BLK_TC_PREFLUSH		BLK_TC_FLUSH
+
+/* The ilog2() calls fall out because they're constant */
+#define MASK_TC_BIT(rw, __name) ((__force u32)(rw & REQ_ ## __name) <<	\
+	  (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
+
+/*
+ * The worker for the various blk_add_trace*() types. Fills out a
+ * blk_io_trace structure and places it in a per-cpu subbuffer.
+ */
+static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
+			    const blk_opf_t opf, u32 what, int error,
+			    int pdu_len, void *pdu_data, u64 cgid)
+{
+	struct task_struct *tsk = current;
+	struct ring_buffer_event *event = NULL;
+	struct trace_buffer *buffer = NULL;
+	struct blk_io_trace *t;
+	unsigned long flags = 0;
+	unsigned long *sequence;
+	unsigned int trace_ctx = 0;
+	pid_t pid;
+	int cpu;
+	bool blk_tracer = blk_tracer_enabled;
+	ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
+	const enum req_op op = opf & REQ_OP_MASK;
+
+	if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
+		return;
+
+	what |= ddir_act[op_is_write(op) ? WRITE : READ];
+	what |= MASK_TC_BIT(opf, SYNC);
+	what |= MASK_TC_BIT(opf, RAHEAD);
+	what |= MASK_TC_BIT(opf, META);
+	what |= MASK_TC_BIT(opf, PREFLUSH);
+	what |= MASK_TC_BIT(opf, FUA);
+	if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
+		what |= BLK_TC_ACT(BLK_TC_DISCARD);
+	if (op == REQ_OP_FLUSH)
+		what |= BLK_TC_ACT(BLK_TC_FLUSH);
+	if (cgid)
+		what |= __BLK_TA_CGROUP;
+
+	pid = tsk->pid;
+	if (act_log_check(bt, what, sector, pid))
+		return;
+	cpu = raw_smp_processor_id();
+
+	if (blk_tracer) {
+		tracing_record_cmdline(current);
+
+		buffer = blk_tr->array_buffer.buffer;
+		trace_ctx = tracing_gen_ctx_flags(0);
+		event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
+						  sizeof(*t) + pdu_len + cgid_len,
+						  trace_ctx);
+		if (!event)
+			return;
+		t = ring_buffer_event_data(event);
+		goto record_it;
+	}
+
+	if (unlikely(tsk->btrace_seq != blktrace_seq))
+		trace_note_tsk(tsk);
+
+	/*
+	 * A word about the locking here - we disable interrupts to reserve
+	 * some space in the relay per-cpu buffer, to prevent an irq
+	 * from coming in and stepping on our toes.
+	 */
+	local_irq_save(flags);
+	t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
+	if (t) {
+		sequence = per_cpu_ptr(bt->sequence, cpu);
+
+		t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
+		t->sequence = ++(*sequence);
+		t->time = ktime_to_ns(ktime_get());
+record_it:
+		/*
+		 * These two are not needed in ftrace as they are in the
+		 * generic trace_entry, filled by tracing_generic_entry_update,
+		 * but for the trace_event->bin() synthesizer benefit we do it
+		 * here too.
+		 */
+		t->cpu = cpu;
+		t->pid = pid;
+
+		t->sector = sector;
+		t->bytes = bytes;
+		t->action = what;
+		t->device = bt->dev;
+		t->error = error;
+		t->pdu_len = pdu_len + cgid_len;
+
+		if (cgid_len)
+			memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
+		if (pdu_len)
+			memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
+
+		if (blk_tracer) {
+			trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
+			return;
+		}
+	}
+
+	local_irq_restore(flags);
+}
+
+static void blk_trace_free(struct request_queue *q, struct blk_trace *bt)
+{
+	relay_close(bt->rchan);
+
+	/*
+	 * If 'bt->dir' is not set, then both 'dropped' and 'msg' are created
+	 * under 'q->debugfs_dir', thus lookup and remove them.
+	 */
+	if (!bt->dir) {
+		debugfs_lookup_and_remove("dropped", q->debugfs_dir);
+		debugfs_lookup_and_remove("msg", q->debugfs_dir);
+	} else {
+		debugfs_remove(bt->dir);
+	}
+	free_percpu(bt->sequence);
+	free_percpu(bt->msg_data);
+	kfree(bt);
+}
+
+static void get_probe_ref(void)
+{
+	mutex_lock(&blk_probe_mutex);
+	if (++blk_probes_ref == 1)
+		blk_register_tracepoints();
+	mutex_unlock(&blk_probe_mutex);
+}
+
+static void put_probe_ref(void)
+{
+	mutex_lock(&blk_probe_mutex);
+	if (!--blk_probes_ref)
+		blk_unregister_tracepoints();
+	mutex_unlock(&blk_probe_mutex);
+}
+
+static int blk_trace_start(struct blk_trace *bt)
+{
+	if (bt->trace_state != Blktrace_setup &&
+	    bt->trace_state != Blktrace_stopped)
+		return -EINVAL;
+
+	blktrace_seq++;
+	smp_mb();
+	bt->trace_state = Blktrace_running;
+	raw_spin_lock_irq(&running_trace_lock);
+	list_add(&bt->running_list, &running_trace_list);
+	raw_spin_unlock_irq(&running_trace_lock);
+	trace_note_time(bt);
+
+	return 0;
+}
+
+static int blk_trace_stop(struct blk_trace *bt)
+{
+	if (bt->trace_state != Blktrace_running)
+		return -EINVAL;
+
+	bt->trace_state = Blktrace_stopped;
+	raw_spin_lock_irq(&running_trace_lock);
+	list_del_init(&bt->running_list);
+	raw_spin_unlock_irq(&running_trace_lock);
+	relay_flush(bt->rchan);
+
+	return 0;
+}
+
+static void blk_trace_cleanup(struct request_queue *q, struct blk_trace *bt)
+{
+	blk_trace_stop(bt);
+	synchronize_rcu();
+	blk_trace_free(q, bt);
+	put_probe_ref();
+}
+
+static int __blk_trace_remove(struct request_queue *q)
+{
+	struct blk_trace *bt;
+
+	bt = rcu_replace_pointer(q->blk_trace, NULL,
+				 lockdep_is_held(&q->debugfs_mutex));
+	if (!bt)
+		return -EINVAL;
+
+	blk_trace_cleanup(q, bt);
+
+	return 0;
+}
+
+int blk_trace_remove(struct request_queue *q)
+{
+	int ret;
+
+	mutex_lock(&q->debugfs_mutex);
+	ret = __blk_trace_remove(q);
+	mutex_unlock(&q->debugfs_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(blk_trace_remove);
+
+static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
+				size_t count, loff_t *ppos)
+{
+	struct blk_trace *bt = filp->private_data;
+	char buf[16];
+
+	snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
+
+	return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
+}
+
+static const struct file_operations blk_dropped_fops = {
+	.owner =	THIS_MODULE,
+	.open =		simple_open,
+	.read =		blk_dropped_read,
+	.llseek =	default_llseek,
+};
+
+static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
+				size_t count, loff_t *ppos)
+{
+	char *msg;
+	struct blk_trace *bt;
+
+	if (count >= BLK_TN_MAX_MSG)
+		return -EINVAL;
+
+	msg = memdup_user_nul(buffer, count);
+	if (IS_ERR(msg))
+		return PTR_ERR(msg);
+
+	bt = filp->private_data;
+	__blk_trace_note_message(bt, NULL, "%s", msg);
+	kfree(msg);
+
+	return count;
+}
+
+static const struct file_operations blk_msg_fops = {
+	.owner =	THIS_MODULE,
+	.open =		simple_open,
+	.write =	blk_msg_write,
+	.llseek =	noop_llseek,
+};
+
+/*
+ * Keep track of how many times we encountered a full subbuffer, to aid
+ * the user space app in telling how many lost events there were.
+ */
+static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
+				     void *prev_subbuf, size_t prev_padding)
+{
+	struct blk_trace *bt;
+
+	if (!relay_buf_full(buf))
+		return 1;
+
+	bt = buf->chan->private_data;
+	atomic_inc(&bt->dropped);
+	return 0;
+}
+
+static int blk_remove_buf_file_callback(struct dentry *dentry)
+{
+	debugfs_remove(dentry);
+
+	return 0;
+}
+
+static struct dentry *blk_create_buf_file_callback(const char *filename,
+						   struct dentry *parent,
+						   umode_t mode,
+						   struct rchan_buf *buf,
+						   int *is_global)
+{
+	return debugfs_create_file(filename, mode, parent, buf,
+					&relay_file_operations);
+}
+
+static const struct rchan_callbacks blk_relay_callbacks = {
+	.subbuf_start		= blk_subbuf_start_callback,
+	.create_buf_file	= blk_create_buf_file_callback,
+	.remove_buf_file	= blk_remove_buf_file_callback,
+};
+
+static void blk_trace_setup_lba(struct blk_trace *bt,
+				struct block_device *bdev)
+{
+	if (bdev) {
+		bt->start_lba = bdev->bd_start_sect;
+		bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev);
+	} else {
+		bt->start_lba = 0;
+		bt->end_lba = -1ULL;
+	}
+}
+
+/*
+ * Setup everything required to start tracing
+ */
+static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
+			      struct block_device *bdev,
+			      struct blk_user_trace_setup *buts)
+{
+	struct blk_trace *bt = NULL;
+	struct dentry *dir = NULL;
+	int ret;
+
+	lockdep_assert_held(&q->debugfs_mutex);
+
+	if (!buts->buf_size || !buts->buf_nr)
+		return -EINVAL;
+
+	strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
+	buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
+
+	/*
+	 * some device names have larger paths - convert the slashes
+	 * to underscores for this to work as expected
+	 */
+	strreplace(buts->name, '/', '_');
+
+	/*
+	 * bdev can be NULL, as with scsi-generic, this is a helpful as
+	 * we can be.
+	 */
+	if (rcu_dereference_protected(q->blk_trace,
+				      lockdep_is_held(&q->debugfs_mutex))) {
+		pr_warn("Concurrent blktraces are not allowed on %s\n",
+			buts->name);
+		return -EBUSY;
+	}
+
+	bt = kzalloc(sizeof(*bt), GFP_KERNEL);
+	if (!bt)
+		return -ENOMEM;
+
+	ret = -ENOMEM;
+	bt->sequence = alloc_percpu(unsigned long);
+	if (!bt->sequence)
+		goto err;
+
+	bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
+	if (!bt->msg_data)
+		goto err;
+
+	/*
+	 * When tracing the whole disk reuse the existing debugfs directory
+	 * created by the block layer on init. For partitions block devices,
+	 * and scsi-generic block devices we create a temporary new debugfs
+	 * directory that will be removed once the trace ends.
+	 */
+	if (bdev && !bdev_is_partition(bdev))
+		dir = q->debugfs_dir;
+	else
+		bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
+
+	/*
+	 * As blktrace relies on debugfs for its interface the debugfs directory
+	 * is required, contrary to the usual mantra of not checking for debugfs
+	 * files or directories.
+	 */
+	if (IS_ERR_OR_NULL(dir)) {
+		pr_warn("debugfs_dir not present for %s so skipping\n",
+			buts->name);
+		ret = -ENOENT;
+		goto err;
+	}
+
+	bt->dev = dev;
+	atomic_set(&bt->dropped, 0);
+	INIT_LIST_HEAD(&bt->running_list);
+
+	ret = -EIO;
+	debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
+	debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
+
+	bt->rchan = relay_open("trace", dir, buts->buf_size,
+				buts->buf_nr, &blk_relay_callbacks, bt);
+	if (!bt->rchan)
+		goto err;
+
+	bt->act_mask = buts->act_mask;
+	if (!bt->act_mask)
+		bt->act_mask = (u16) -1;
+
+	blk_trace_setup_lba(bt, bdev);
+
+	/* overwrite with user settings */
+	if (buts->start_lba)
+		bt->start_lba = buts->start_lba;
+	if (buts->end_lba)
+		bt->end_lba = buts->end_lba;
+
+	bt->pid = buts->pid;
+	bt->trace_state = Blktrace_setup;
+
+	rcu_assign_pointer(q->blk_trace, bt);
+	get_probe_ref();
+
+	ret = 0;
+err:
+	if (ret)
+		blk_trace_free(q, bt);
+	return ret;
+}
+
+static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
+			     struct block_device *bdev, char __user *arg)
+{
+	struct blk_user_trace_setup buts;
+	int ret;
+
+	ret = copy_from_user(&buts, arg, sizeof(buts));
+	if (ret)
+		return -EFAULT;
+
+	ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
+	if (ret)
+		return ret;
+
+	if (copy_to_user(arg, &buts, sizeof(buts))) {
+		__blk_trace_remove(q);
+		return -EFAULT;
+	}
+	return 0;
+}
+
+int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
+		    struct block_device *bdev,
+		    char __user *arg)
+{
+	int ret;
+
+	mutex_lock(&q->debugfs_mutex);
+	ret = __blk_trace_setup(q, name, dev, bdev, arg);
+	mutex_unlock(&q->debugfs_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(blk_trace_setup);
+
+#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
+static int compat_blk_trace_setup(struct request_queue *q, char *name,
+				  dev_t dev, struct block_device *bdev,
+				  char __user *arg)
+{
+	struct blk_user_trace_setup buts;
+	struct compat_blk_user_trace_setup cbuts;
+	int ret;
+
+	if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
+		return -EFAULT;
+
+	buts = (struct blk_user_trace_setup) {
+		.act_mask = cbuts.act_mask,
+		.buf_size = cbuts.buf_size,
+		.buf_nr = cbuts.buf_nr,
+		.start_lba = cbuts.start_lba,
+		.end_lba = cbuts.end_lba,
+		.pid = cbuts.pid,
+	};
+
+	ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
+	if (ret)
+		return ret;
+
+	if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
+		__blk_trace_remove(q);
+		return -EFAULT;
+	}
+
+	return 0;
+}
+#endif
+
+static int __blk_trace_startstop(struct request_queue *q, int start)
+{
+	struct blk_trace *bt;
+
+	bt = rcu_dereference_protected(q->blk_trace,
+				       lockdep_is_held(&q->debugfs_mutex));
+	if (bt == NULL)
+		return -EINVAL;
+
+	if (start)
+		return blk_trace_start(bt);
+	else
+		return blk_trace_stop(bt);
+}
+
+int blk_trace_startstop(struct request_queue *q, int start)
+{
+	int ret;
+
+	mutex_lock(&q->debugfs_mutex);
+	ret = __blk_trace_startstop(q, start);
+	mutex_unlock(&q->debugfs_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(blk_trace_startstop);
+
+/*
+ * When reading or writing the blktrace sysfs files, the references to the
+ * opened sysfs or device files should prevent the underlying block device
+ * from being removed. So no further delete protection is really needed.
+ */
+
+/**
+ * blk_trace_ioctl: - handle the ioctls associated with tracing
+ * @bdev:	the block device
+ * @cmd:	the ioctl cmd
+ * @arg:	the argument data, if any
+ *
+ **/
+int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
+{
+	struct request_queue *q;
+	int ret, start = 0;
+	char b[BDEVNAME_SIZE];
+
+	q = bdev_get_queue(bdev);
+	if (!q)
+		return -ENXIO;
+
+	mutex_lock(&q->debugfs_mutex);
+
+	switch (cmd) {
+	case BLKTRACESETUP:
+		snprintf(b, sizeof(b), "%pg", bdev);
+		ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
+		break;
+#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
+	case BLKTRACESETUP32:
+		snprintf(b, sizeof(b), "%pg", bdev);
+		ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
+		break;
+#endif
+	case BLKTRACESTART:
+		start = 1;
+		fallthrough;
+	case BLKTRACESTOP:
+		ret = __blk_trace_startstop(q, start);
+		break;
+	case BLKTRACETEARDOWN:
+		ret = __blk_trace_remove(q);
+		break;
+	default:
+		ret = -ENOTTY;
+		break;
+	}
+
+	mutex_unlock(&q->debugfs_mutex);
+	return ret;
+}
+
+/**
+ * blk_trace_shutdown: - stop and cleanup trace structures
+ * @q:    the request queue associated with the device
+ *
+ **/
+void blk_trace_shutdown(struct request_queue *q)
+{
+	if (rcu_dereference_protected(q->blk_trace,
+				      lockdep_is_held(&q->debugfs_mutex)))
+		__blk_trace_remove(q);
+}
+
+#ifdef CONFIG_BLK_CGROUP
+static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
+{
+	struct cgroup_subsys_state *blkcg_css;
+	struct blk_trace *bt;
+
+	/* We don't use the 'bt' value here except as an optimization... */
+	bt = rcu_dereference_protected(q->blk_trace, 1);
+	if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
+		return 0;
+
+	blkcg_css = bio_blkcg_css(bio);
+	if (!blkcg_css)
+		return 0;
+	return cgroup_id(blkcg_css->cgroup);
+}
+#else
+static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
+{
+	return 0;
+}
+#endif
+
+static u64
+blk_trace_request_get_cgid(struct request *rq)
+{
+	if (!rq->bio)
+		return 0;
+	/* Use the first bio */
+	return blk_trace_bio_get_cgid(rq->q, rq->bio);
+}
+
+/*
+ * blktrace probes
+ */
+
+/**
+ * blk_add_trace_rq - Add a trace for a request oriented action
+ * @rq:		the source request
+ * @error:	return status to log
+ * @nr_bytes:	number of completed bytes
+ * @what:	the action
+ * @cgid:	the cgroup info
+ *
+ * Description:
+ *     Records an action against a request. Will log the bio offset + size.
+ *
+ **/
+static void blk_add_trace_rq(struct request *rq, blk_status_t error,
+			     unsigned int nr_bytes, u32 what, u64 cgid)
+{
+	struct blk_trace *bt;
+
+	rcu_read_lock();
+	bt = rcu_dereference(rq->q->blk_trace);
+	if (likely(!bt)) {
+		rcu_read_unlock();
+		return;
+	}
+
+	if (blk_rq_is_passthrough(rq))
+		what |= BLK_TC_ACT(BLK_TC_PC);
+	else
+		what |= BLK_TC_ACT(BLK_TC_FS);
+
+	__blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, rq->cmd_flags,
+			what, blk_status_to_errno(error), 0, NULL, cgid);
+	rcu_read_unlock();
+}
+
+static void blk_add_trace_rq_insert(void *ignore, struct request *rq)
+{
+	blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
+			 blk_trace_request_get_cgid(rq));
+}
+
+static void blk_add_trace_rq_issue(void *ignore, struct request *rq)
+{
+	blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
+			 blk_trace_request_get_cgid(rq));
+}
+
+static void blk_add_trace_rq_merge(void *ignore, struct request *rq)
+{
+	blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE,
+			 blk_trace_request_get_cgid(rq));
+}
+
+static void blk_add_trace_rq_requeue(void *ignore, struct request *rq)
+{
+	blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
+			 blk_trace_request_get_cgid(rq));
+}
+
+static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
+			blk_status_t error, unsigned int nr_bytes)
+{
+	blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
+			 blk_trace_request_get_cgid(rq));
+}
+
+/**
+ * blk_add_trace_bio - Add a trace for a bio oriented action
+ * @q:		queue the io is for
+ * @bio:	the source bio
+ * @what:	the action
+ * @error:	error, if any
+ *
+ * Description:
+ *     Records an action against a bio. Will log the bio offset + size.
+ *
+ **/
+static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
+			      u32 what, int error)
+{
+	struct blk_trace *bt;
+
+	rcu_read_lock();
+	bt = rcu_dereference(q->blk_trace);
+	if (likely(!bt)) {
+		rcu_read_unlock();
+		return;
+	}
+
+	__blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
+			bio->bi_opf, what, error, 0, NULL,
+			blk_trace_bio_get_cgid(q, bio));
+	rcu_read_unlock();
+}
+
+static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio)
+{
+	blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BOUNCE, 0);
+}
+
+static void blk_add_trace_bio_complete(void *ignore,
+				       struct request_queue *q, struct bio *bio)
+{
+	blk_add_trace_bio(q, bio, BLK_TA_COMPLETE,
+			  blk_status_to_errno(bio->bi_status));
+}
+
+static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio)
+{
+	blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE,
+			0);
+}
+
+static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio)
+{
+	blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE,
+			0);
+}
+
+static void blk_add_trace_bio_queue(void *ignore, struct bio *bio)
+{
+	blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, 0);
+}
+
+static void blk_add_trace_getrq(void *ignore, struct bio *bio)
+{
+	blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, 0);
+}
+
+static void blk_add_trace_plug(void *ignore, struct request_queue *q)
+{
+	struct blk_trace *bt;
+
+	rcu_read_lock();
+	bt = rcu_dereference(q->blk_trace);
+	if (bt)
+		__blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0);
+	rcu_read_unlock();
+}
+
+static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
+				    unsigned int depth, bool explicit)
+{
+	struct blk_trace *bt;
+
+	rcu_read_lock();
+	bt = rcu_dereference(q->blk_trace);
+	if (bt) {
+		__be64 rpdu = cpu_to_be64(depth);
+		u32 what;
+
+		if (explicit)
+			what = BLK_TA_UNPLUG_IO;
+		else
+			what = BLK_TA_UNPLUG_TIMER;
+
+		__blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0);
+	}
+	rcu_read_unlock();
+}
+
+static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
+{
+	struct request_queue *q = bio->bi_bdev->bd_disk->queue;
+	struct blk_trace *bt;
+
+	rcu_read_lock();
+	bt = rcu_dereference(q->blk_trace);
+	if (bt) {
+		__be64 rpdu = cpu_to_be64(pdu);
+
+		__blk_add_trace(bt, bio->bi_iter.bi_sector,
+				bio->bi_iter.bi_size, bio->bi_opf, BLK_TA_SPLIT,
+				blk_status_to_errno(bio->bi_status),
+				sizeof(rpdu), &rpdu,
+				blk_trace_bio_get_cgid(q, bio));
+	}
+	rcu_read_unlock();
+}
+
+/**
+ * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
+ * @ignore:	trace callback data parameter (not used)
+ * @bio:	the source bio
+ * @dev:	source device
+ * @from:	source sector
+ *
+ * Called after a bio is remapped to a different device and/or sector.
+ **/
+static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev,
+				    sector_t from)
+{
+	struct request_queue *q = bio->bi_bdev->bd_disk->queue;
+	struct blk_trace *bt;
+	struct blk_io_trace_remap r;
+
+	rcu_read_lock();
+	bt = rcu_dereference(q->blk_trace);
+	if (likely(!bt)) {
+		rcu_read_unlock();
+		return;
+	}
+
+	r.device_from = cpu_to_be32(dev);
+	r.device_to   = cpu_to_be32(bio_dev(bio));
+	r.sector_from = cpu_to_be64(from);
+
+	__blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
+			bio->bi_opf, BLK_TA_REMAP,
+			blk_status_to_errno(bio->bi_status),
+			sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
+	rcu_read_unlock();
+}
+
+/**
+ * blk_add_trace_rq_remap - Add a trace for a request-remap operation
+ * @ignore:	trace callback data parameter (not used)
+ * @rq:		the source request
+ * @dev:	target device
+ * @from:	source sector
+ *
+ * Description:
+ *     Device mapper remaps request to other devices.
+ *     Add a trace for that action.
+ *
+ **/
+static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev,
+				   sector_t from)
+{
+	struct blk_trace *bt;
+	struct blk_io_trace_remap r;
+
+	rcu_read_lock();
+	bt = rcu_dereference(rq->q->blk_trace);
+	if (likely(!bt)) {
+		rcu_read_unlock();
+		return;
+	}
+
+	r.device_from = cpu_to_be32(dev);
+	r.device_to   = cpu_to_be32(disk_devt(rq->q->disk));
+	r.sector_from = cpu_to_be64(from);
+
+	__blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
+			rq->cmd_flags, BLK_TA_REMAP, 0,
+			sizeof(r), &r, blk_trace_request_get_cgid(rq));
+	rcu_read_unlock();
+}
+
+/**
+ * blk_add_driver_data - Add binary message with driver-specific data
+ * @rq:		io request
+ * @data:	driver-specific data
+ * @len:	length of driver-specific data
+ *
+ * Description:
+ *     Some drivers might want to write driver-specific data per request.
+ *
+ **/
+void blk_add_driver_data(struct request *rq, void *data, size_t len)
+{
+	struct blk_trace *bt;
+
+	rcu_read_lock();
+	bt = rcu_dereference(rq->q->blk_trace);
+	if (likely(!bt)) {
+		rcu_read_unlock();
+		return;
+	}
+
+	__blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0,
+				BLK_TA_DRV_DATA, 0, len, data,
+				blk_trace_request_get_cgid(rq));
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(blk_add_driver_data);
+
+static void blk_register_tracepoints(void)
+{
+	int ret;
+
+	ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_plug(blk_add_trace_plug, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_split(blk_add_trace_split, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
+	WARN_ON(ret);
+	ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
+	WARN_ON(ret);
+}
+
+static void blk_unregister_tracepoints(void)
+{
+	unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
+	unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
+	unregister_trace_block_split(blk_add_trace_split, NULL);
+	unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
+	unregister_trace_block_plug(blk_add_trace_plug, NULL);
+	unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
+	unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
+	unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
+	unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
+	unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
+	unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
+	unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
+	unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
+	unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
+	unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
+	unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
+
+	tracepoint_synchronize_unregister();
+}
+
+/*
+ * struct blk_io_tracer formatting routines
+ */
+
+static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
+{
+	int i = 0;
+	int tc = t->action >> BLK_TC_SHIFT;
+
+	if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
+		rwbs[i++] = 'N';
+		goto out;
+	}
+
+	if (tc & BLK_TC_FLUSH)
+		rwbs[i++] = 'F';
+
+	if (tc & BLK_TC_DISCARD)
+		rwbs[i++] = 'D';
+	else if (tc & BLK_TC_WRITE)
+		rwbs[i++] = 'W';
+	else if (t->bytes)
+		rwbs[i++] = 'R';
+	else
+		rwbs[i++] = 'N';
+
+	if (tc & BLK_TC_FUA)
+		rwbs[i++] = 'F';
+	if (tc & BLK_TC_AHEAD)
+		rwbs[i++] = 'A';
+	if (tc & BLK_TC_SYNC)
+		rwbs[i++] = 'S';
+	if (tc & BLK_TC_META)
+		rwbs[i++] = 'M';
+out:
+	rwbs[i] = '\0';
+}
+
+static inline
+const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
+{
+	return (const struct blk_io_trace *)ent;
+}
+
+static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
+{
+	return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0);
+}
+
+static inline u64 t_cgid(const struct trace_entry *ent)
+{
+	return *(u64 *)(te_blk_io_trace(ent) + 1);
+}
+
+static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
+{
+	return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0);
+}
+
+static inline u32 t_action(const struct trace_entry *ent)
+{
+	return te_blk_io_trace(ent)->action;
+}
+
+static inline u32 t_bytes(const struct trace_entry *ent)
+{
+	return te_blk_io_trace(ent)->bytes;
+}
+
+static inline u32 t_sec(const struct trace_entry *ent)
+{
+	return te_blk_io_trace(ent)->bytes >> 9;
+}
+
+static inline unsigned long long t_sector(const struct trace_entry *ent)
+{
+	return te_blk_io_trace(ent)->sector;
+}
+
+static inline __u16 t_error(const struct trace_entry *ent)
+{
+	return te_blk_io_trace(ent)->error;
+}
+
+static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
+{
+	const __be64 *val = pdu_start(ent, has_cg);
+	return be64_to_cpu(*val);
+}
+
+typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
+	bool has_cg);
+
+static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
+	bool has_cg)
+{
+	char rwbs[RWBS_LEN];
+	unsigned long long ts  = iter->ts;
+	unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
+	unsigned secs	       = (unsigned long)ts;
+	const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
+
+	fill_rwbs(rwbs, t);
+
+	trace_seq_printf(&iter->seq,
+			 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
+			 MAJOR(t->device), MINOR(t->device), iter->cpu,
+			 secs, nsec_rem, iter->ent->pid, act, rwbs);
+}
+
+static void blk_log_action(struct trace_iterator *iter, const char *act,
+	bool has_cg)
+{
+	char rwbs[RWBS_LEN];
+	const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
+
+	fill_rwbs(rwbs, t);
+	if (has_cg) {
+		u64 id = t_cgid(iter->ent);
+
+		if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
+			char blkcg_name_buf[NAME_MAX + 1] = "<...>";
+
+			cgroup_path_from_kernfs_id(id, blkcg_name_buf,
+				sizeof(blkcg_name_buf));
+			trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
+				 MAJOR(t->device), MINOR(t->device),
+				 blkcg_name_buf, act, rwbs);
+		} else {
+			/*
+			 * The cgid portion used to be "INO,GEN".  Userland
+			 * builds a FILEID_INO32_GEN fid out of them and
+			 * opens the cgroup using open_by_handle_at(2).
+			 * While 32bit ino setups are still the same, 64bit
+			 * ones now use the 64bit ino as the whole ID and
+			 * no longer use generation.
+			 *
+			 * Regardless of the content, always output
+			 * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
+			 * be mapped back to @id on both 64 and 32bit ino
+			 * setups.  See __kernfs_fh_to_dentry().
+			 */
+			trace_seq_printf(&iter->seq,
+				 "%3d,%-3d %llx,%-llx %2s %3s ",
+				 MAJOR(t->device), MINOR(t->device),
+				 id & U32_MAX, id >> 32, act, rwbs);
+		}
+	} else
+		trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
+				 MAJOR(t->device), MINOR(t->device), act, rwbs);
+}
+
+static void blk_log_dump_pdu(struct trace_seq *s,
+	const struct trace_entry *ent, bool has_cg)
+{
+	const unsigned char *pdu_buf;
+	int pdu_len;
+	int i, end;
+
+	pdu_buf = pdu_start(ent, has_cg);
+	pdu_len = pdu_real_len(ent, has_cg);
+
+	if (!pdu_len)
+		return;
+
+	/* find the last zero that needs to be printed */
+	for (end = pdu_len - 1; end >= 0; end--)
+		if (pdu_buf[end])
+			break;
+	end++;
+
+	trace_seq_putc(s, '(');
+
+	for (i = 0; i < pdu_len; i++) {
+
+		trace_seq_printf(s, "%s%02x",
+				 i == 0 ? "" : " ", pdu_buf[i]);
+
+		/*
+		 * stop when the rest is just zeros and indicate so
+		 * with a ".." appended
+		 */
+		if (i == end && end != pdu_len - 1) {
+			trace_seq_puts(s, " ..) ");
+			return;
+		}
+	}
+
+	trace_seq_puts(s, ") ");
+}
+
+static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
+{
+	char cmd[TASK_COMM_LEN];
+
+	trace_find_cmdline(ent->pid, cmd);
+
+	if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
+		trace_seq_printf(s, "%u ", t_bytes(ent));
+		blk_log_dump_pdu(s, ent, has_cg);
+		trace_seq_printf(s, "[%s]\n", cmd);
+	} else {
+		if (t_sec(ent))
+			trace_seq_printf(s, "%llu + %u [%s]\n",
+						t_sector(ent), t_sec(ent), cmd);
+		else
+			trace_seq_printf(s, "[%s]\n", cmd);
+	}
+}
+
+static void blk_log_with_error(struct trace_seq *s,
+			      const struct trace_entry *ent, bool has_cg)
+{
+	if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
+		blk_log_dump_pdu(s, ent, has_cg);
+		trace_seq_printf(s, "[%d]\n", t_error(ent));
+	} else {
+		if (t_sec(ent))
+			trace_seq_printf(s, "%llu + %u [%d]\n",
+					 t_sector(ent),
+					 t_sec(ent), t_error(ent));
+		else
+			trace_seq_printf(s, "%llu [%d]\n",
+					 t_sector(ent), t_error(ent));
+	}
+}
+
+static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
+{
+	const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
+
+	trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
+			 t_sector(ent), t_sec(ent),
+			 MAJOR(be32_to_cpu(__r->device_from)),
+			 MINOR(be32_to_cpu(__r->device_from)),
+			 be64_to_cpu(__r->sector_from));
+}
+
+static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
+{
+	char cmd[TASK_COMM_LEN];
+
+	trace_find_cmdline(ent->pid, cmd);
+
+	trace_seq_printf(s, "[%s]\n", cmd);
+}
+
+static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
+{
+	char cmd[TASK_COMM_LEN];
+
+	trace_find_cmdline(ent->pid, cmd);
+
+	trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
+}
+
+static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
+{
+	char cmd[TASK_COMM_LEN];
+
+	trace_find_cmdline(ent->pid, cmd);
+
+	trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
+			 get_pdu_int(ent, has_cg), cmd);
+}
+
+static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
+			bool has_cg)
+{
+
+	trace_seq_putmem(s, pdu_start(ent, has_cg),
+		pdu_real_len(ent, has_cg));
+	trace_seq_putc(s, '\n');
+}
+
+/*
+ * struct tracer operations
+ */
+
+static void blk_tracer_print_header(struct seq_file *m)
+{
+	if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
+		return;
+	seq_puts(m, "# DEV   CPU TIMESTAMP     PID ACT FLG\n"
+		    "#  |     |     |           |   |   |\n");
+}
+
+static void blk_tracer_start(struct trace_array *tr)
+{
+	blk_tracer_enabled = true;
+}
+
+static int blk_tracer_init(struct trace_array *tr)
+{
+	blk_tr = tr;
+	blk_tracer_start(tr);
+	return 0;
+}
+
+static void blk_tracer_stop(struct trace_array *tr)
+{
+	blk_tracer_enabled = false;
+}
+
+static void blk_tracer_reset(struct trace_array *tr)
+{
+	blk_tracer_stop(tr);
+}
+
+static const struct {
+	const char *act[2];
+	void	   (*print)(struct trace_seq *s, const struct trace_entry *ent,
+			    bool has_cg);
+} what2act[] = {
+	[__BLK_TA_QUEUE]	= {{  "Q", "queue" },	   blk_log_generic },
+	[__BLK_TA_BACKMERGE]	= {{  "M", "backmerge" },  blk_log_generic },
+	[__BLK_TA_FRONTMERGE]	= {{  "F", "frontmerge" }, blk_log_generic },
+	[__BLK_TA_GETRQ]	= {{  "G", "getrq" },	   blk_log_generic },
+	[__BLK_TA_SLEEPRQ]	= {{  "S", "sleeprq" },	   blk_log_generic },
+	[__BLK_TA_REQUEUE]	= {{  "R", "requeue" },	   blk_log_with_error },
+	[__BLK_TA_ISSUE]	= {{  "D", "issue" },	   blk_log_generic },
+	[__BLK_TA_COMPLETE]	= {{  "C", "complete" },   blk_log_with_error },
+	[__BLK_TA_PLUG]		= {{  "P", "plug" },	   blk_log_plug },
+	[__BLK_TA_UNPLUG_IO]	= {{  "U", "unplug_io" },  blk_log_unplug },
+	[__BLK_TA_UNPLUG_TIMER]	= {{ "UT", "unplug_timer" }, blk_log_unplug },
+	[__BLK_TA_INSERT]	= {{  "I", "insert" },	   blk_log_generic },
+	[__BLK_TA_SPLIT]	= {{  "X", "split" },	   blk_log_split },
+	[__BLK_TA_BOUNCE]	= {{  "B", "bounce" },	   blk_log_generic },
+	[__BLK_TA_REMAP]	= {{  "A", "remap" },	   blk_log_remap },
+};
+
+static enum print_line_t print_one_line(struct trace_iterator *iter,
+					bool classic)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	const struct blk_io_trace *t;
+	u16 what;
+	bool long_act;
+	blk_log_action_t *log_action;
+	bool has_cg;
+
+	t	   = te_blk_io_trace(iter->ent);
+	what	   = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
+	long_act   = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
+	log_action = classic ? &blk_log_action_classic : &blk_log_action;
+	has_cg	   = t->action & __BLK_TA_CGROUP;
+
+	if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
+		log_action(iter, long_act ? "message" : "m", has_cg);
+		blk_log_msg(s, iter->ent, has_cg);
+		return trace_handle_return(s);
+	}
+
+	if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
+		trace_seq_printf(s, "Unknown action %x\n", what);
+	else {
+		log_action(iter, what2act[what].act[long_act], has_cg);
+		what2act[what].print(s, iter->ent, has_cg);
+	}
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
+					       int flags, struct trace_event *event)
+{
+	return print_one_line(iter, false);
+}
+
+static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
+{
+	struct trace_seq *s = &iter->seq;
+	struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
+	const int offset = offsetof(struct blk_io_trace, sector);
+	struct blk_io_trace old = {
+		.magic	  = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
+		.time     = iter->ts,
+	};
+
+	trace_seq_putmem(s, &old, offset);
+	trace_seq_putmem(s, &t->sector,
+			 sizeof(old) - offset + t->pdu_len);
+}
+
+static enum print_line_t
+blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
+			     struct trace_event *event)
+{
+	blk_trace_synthesize_old_trace(iter);
+
+	return trace_handle_return(&iter->seq);
+}
+
+static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
+{
+	if ((iter->ent->type != TRACE_BLK) ||
+	    !(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
+		return TRACE_TYPE_UNHANDLED;
+
+	return print_one_line(iter, true);
+}
+
+static int
+blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
+{
+	/* don't output context-info for blk_classic output */
+	if (bit == TRACE_BLK_OPT_CLASSIC) {
+		if (set)
+			tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
+		else
+			tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
+	}
+	return 0;
+}
+
+static struct tracer blk_tracer __read_mostly = {
+	.name		= "blk",
+	.init		= blk_tracer_init,
+	.reset		= blk_tracer_reset,
+	.start		= blk_tracer_start,
+	.stop		= blk_tracer_stop,
+	.print_header	= blk_tracer_print_header,
+	.print_line	= blk_tracer_print_line,
+	.flags		= &blk_tracer_flags,
+	.set_flag	= blk_tracer_set_flag,
+};
+
+static struct trace_event_functions trace_blk_event_funcs = {
+	.trace		= blk_trace_event_print,
+	.binary		= blk_trace_event_print_binary,
+};
+
+static struct trace_event trace_blk_event = {
+	.type		= TRACE_BLK,
+	.funcs		= &trace_blk_event_funcs,
+};
+
+static int __init init_blk_tracer(void)
+{
+	if (!register_trace_event(&trace_blk_event)) {
+		pr_warn("Warning: could not register block events\n");
+		return 1;
+	}
+
+	if (register_tracer(&blk_tracer) != 0) {
+		pr_warn("Warning: could not register the block tracer\n");
+		unregister_trace_event(&trace_blk_event);
+		return 1;
+	}
+
+	return 0;
+}
+
+device_initcall(init_blk_tracer);
+
+static int blk_trace_remove_queue(struct request_queue *q)
+{
+	struct blk_trace *bt;
+
+	bt = rcu_replace_pointer(q->blk_trace, NULL,
+				 lockdep_is_held(&q->debugfs_mutex));
+	if (bt == NULL)
+		return -EINVAL;
+
+	blk_trace_stop(bt);
+
+	put_probe_ref();
+	synchronize_rcu();
+	blk_trace_free(q, bt);
+	return 0;
+}
+
+/*
+ * Setup everything required to start tracing
+ */
+static int blk_trace_setup_queue(struct request_queue *q,
+				 struct block_device *bdev)
+{
+	struct blk_trace *bt = NULL;
+	int ret = -ENOMEM;
+
+	bt = kzalloc(sizeof(*bt), GFP_KERNEL);
+	if (!bt)
+		return -ENOMEM;
+
+	bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
+	if (!bt->msg_data)
+		goto free_bt;
+
+	bt->dev = bdev->bd_dev;
+	bt->act_mask = (u16)-1;
+
+	blk_trace_setup_lba(bt, bdev);
+
+	rcu_assign_pointer(q->blk_trace, bt);
+	get_probe_ref();
+	return 0;
+
+free_bt:
+	blk_trace_free(q, bt);
+	return ret;
+}
+
+/*
+ * sysfs interface to enable and configure tracing
+ */
+
+static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf);
+static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
+					  struct device_attribute *attr,
+					  const char *buf, size_t count);
+#define BLK_TRACE_DEVICE_ATTR(_name) \
+	DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
+		    sysfs_blk_trace_attr_show, \
+		    sysfs_blk_trace_attr_store)
+
+static BLK_TRACE_DEVICE_ATTR(enable);
+static BLK_TRACE_DEVICE_ATTR(act_mask);
+static BLK_TRACE_DEVICE_ATTR(pid);
+static BLK_TRACE_DEVICE_ATTR(start_lba);
+static BLK_TRACE_DEVICE_ATTR(end_lba);
+
+static struct attribute *blk_trace_attrs[] = {
+	&dev_attr_enable.attr,
+	&dev_attr_act_mask.attr,
+	&dev_attr_pid.attr,
+	&dev_attr_start_lba.attr,
+	&dev_attr_end_lba.attr,
+	NULL
+};
+
+struct attribute_group blk_trace_attr_group = {
+	.name  = "trace",
+	.attrs = blk_trace_attrs,
+};
+
+static const struct {
+	int mask;
+	const char *str;
+} mask_maps[] = {
+	{ BLK_TC_READ,		"read"		},
+	{ BLK_TC_WRITE,		"write"		},
+	{ BLK_TC_FLUSH,		"flush"		},
+	{ BLK_TC_SYNC,		"sync"		},
+	{ BLK_TC_QUEUE,		"queue"		},
+	{ BLK_TC_REQUEUE,	"requeue"	},
+	{ BLK_TC_ISSUE,		"issue"		},
+	{ BLK_TC_COMPLETE,	"complete"	},
+	{ BLK_TC_FS,		"fs"		},
+	{ BLK_TC_PC,		"pc"		},
+	{ BLK_TC_NOTIFY,	"notify"	},
+	{ BLK_TC_AHEAD,		"ahead"		},
+	{ BLK_TC_META,		"meta"		},
+	{ BLK_TC_DISCARD,	"discard"	},
+	{ BLK_TC_DRV_DATA,	"drv_data"	},
+	{ BLK_TC_FUA,		"fua"		},
+};
+
+static int blk_trace_str2mask(const char *str)
+{
+	int i;
+	int mask = 0;
+	char *buf, *s, *token;
+
+	buf = kstrdup(str, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+	s = strstrip(buf);
+
+	while (1) {
+		token = strsep(&s, ",");
+		if (token == NULL)
+			break;
+
+		if (*token == '\0')
+			continue;
+
+		for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
+			if (strcasecmp(token, mask_maps[i].str) == 0) {
+				mask |= mask_maps[i].mask;
+				break;
+			}
+		}
+		if (i == ARRAY_SIZE(mask_maps)) {
+			mask = -EINVAL;
+			break;
+		}
+	}
+	kfree(buf);
+
+	return mask;
+}
+
+static ssize_t blk_trace_mask2str(char *buf, int mask)
+{
+	int i;
+	char *p = buf;
+
+	for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
+		if (mask & mask_maps[i].mask) {
+			p += sprintf(p, "%s%s",
+				    (p == buf) ? "" : ",", mask_maps[i].str);
+		}
+	}
+	*p++ = '\n';
+
+	return p - buf;
+}
+
+static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct block_device *bdev = dev_to_bdev(dev);
+	struct request_queue *q = bdev_get_queue(bdev);
+	struct blk_trace *bt;
+	ssize_t ret = -ENXIO;
+
+	mutex_lock(&q->debugfs_mutex);
+
+	bt = rcu_dereference_protected(q->blk_trace,
+				       lockdep_is_held(&q->debugfs_mutex));
+	if (attr == &dev_attr_enable) {
+		ret = sprintf(buf, "%u\n", !!bt);
+		goto out_unlock_bdev;
+	}
+
+	if (bt == NULL)
+		ret = sprintf(buf, "disabled\n");
+	else if (attr == &dev_attr_act_mask)
+		ret = blk_trace_mask2str(buf, bt->act_mask);
+	else if (attr == &dev_attr_pid)
+		ret = sprintf(buf, "%u\n", bt->pid);
+	else if (attr == &dev_attr_start_lba)
+		ret = sprintf(buf, "%llu\n", bt->start_lba);
+	else if (attr == &dev_attr_end_lba)
+		ret = sprintf(buf, "%llu\n", bt->end_lba);
+
+out_unlock_bdev:
+	mutex_unlock(&q->debugfs_mutex);
+	return ret;
+}
+
+static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
+					  struct device_attribute *attr,
+					  const char *buf, size_t count)
+{
+	struct block_device *bdev = dev_to_bdev(dev);
+	struct request_queue *q = bdev_get_queue(bdev);
+	struct blk_trace *bt;
+	u64 value;
+	ssize_t ret = -EINVAL;
+
+	if (count == 0)
+		goto out;
+
+	if (attr == &dev_attr_act_mask) {
+		if (kstrtoull(buf, 0, &value)) {
+			/* Assume it is a list of trace category names */
+			ret = blk_trace_str2mask(buf);
+			if (ret < 0)
+				goto out;
+			value = ret;
+		}
+	} else {
+		if (kstrtoull(buf, 0, &value))
+			goto out;
+	}
+
+	mutex_lock(&q->debugfs_mutex);
+
+	bt = rcu_dereference_protected(q->blk_trace,
+				       lockdep_is_held(&q->debugfs_mutex));
+	if (attr == &dev_attr_enable) {
+		if (!!value == !!bt) {
+			ret = 0;
+			goto out_unlock_bdev;
+		}
+		if (value)
+			ret = blk_trace_setup_queue(q, bdev);
+		else
+			ret = blk_trace_remove_queue(q);
+		goto out_unlock_bdev;
+	}
+
+	ret = 0;
+	if (bt == NULL) {
+		ret = blk_trace_setup_queue(q, bdev);
+		bt = rcu_dereference_protected(q->blk_trace,
+				lockdep_is_held(&q->debugfs_mutex));
+	}
+
+	if (ret == 0) {
+		if (attr == &dev_attr_act_mask)
+			bt->act_mask = value;
+		else if (attr == &dev_attr_pid)
+			bt->pid = value;
+		else if (attr == &dev_attr_start_lba)
+			bt->start_lba = value;
+		else if (attr == &dev_attr_end_lba)
+			bt->end_lba = value;
+	}
+
+out_unlock_bdev:
+	mutex_unlock(&q->debugfs_mutex);
+out:
+	return ret ? ret : count;
+}
+#endif /* CONFIG_BLK_DEV_IO_TRACE */
+
+#ifdef CONFIG_EVENT_TRACING
+
+/**
+ * blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string.
+ * @rwbs:	buffer to be filled
+ * @opf:	request operation type (REQ_OP_XXX) and flags for the tracepoint
+ *
+ * Description:
+ *     Maps each request operation and flag to a single character and fills the
+ *     buffer provided by the caller with resulting string.
+ *
+ **/
+void blk_fill_rwbs(char *rwbs, blk_opf_t opf)
+{
+	int i = 0;
+
+	if (opf & REQ_PREFLUSH)
+		rwbs[i++] = 'F';
+
+	switch (opf & REQ_OP_MASK) {
+	case REQ_OP_WRITE:
+		rwbs[i++] = 'W';
+		break;
+	case REQ_OP_DISCARD:
+		rwbs[i++] = 'D';
+		break;
+	case REQ_OP_SECURE_ERASE:
+		rwbs[i++] = 'D';
+		rwbs[i++] = 'E';
+		break;
+	case REQ_OP_FLUSH:
+		rwbs[i++] = 'F';
+		break;
+	case REQ_OP_READ:
+		rwbs[i++] = 'R';
+		break;
+	default:
+		rwbs[i++] = 'N';
+	}
+
+	if (opf & REQ_FUA)
+		rwbs[i++] = 'F';
+	if (opf & REQ_RAHEAD)
+		rwbs[i++] = 'A';
+	if (opf & REQ_SYNC)
+		rwbs[i++] = 'S';
+	if (opf & REQ_META)
+		rwbs[i++] = 'M';
+
+	rwbs[i] = '\0';
+}
+EXPORT_SYMBOL_GPL(blk_fill_rwbs);
+
+#endif /* CONFIG_EVENT_TRACING */
+
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
new file mode 100644
index 000000000..f4a494a45
--- /dev/null
+++ b/kernel/trace/bpf_trace.c
@@ -0,0 +1,2842 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com
+ * Copyright (c) 2016 Facebook
+ */
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/bpf.h>
+#include <linux/bpf_perf_event.h>
+#include <linux/btf.h>
+#include <linux/filter.h>
+#include <linux/uaccess.h>
+#include <linux/ctype.h>
+#include <linux/kprobes.h>
+#include <linux/spinlock.h>
+#include <linux/syscalls.h>
+#include <linux/error-injection.h>
+#include <linux/btf_ids.h>
+#include <linux/bpf_lsm.h>
+#include <linux/fprobe.h>
+#include <linux/bsearch.h>
+#include <linux/sort.h>
+#include <linux/key.h>
+#include <linux/verification.h>
+
+#include <net/bpf_sk_storage.h>
+
+#include <uapi/linux/bpf.h>
+#include <uapi/linux/btf.h>
+
+#include <asm/tlb.h>
+
+#include "trace_probe.h"
+#include "trace.h"
+
+#define CREATE_TRACE_POINTS
+#include "bpf_trace.h"
+
+#define bpf_event_rcu_dereference(p)					\
+	rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex))
+
+#ifdef CONFIG_MODULES
+struct bpf_trace_module {
+	struct module *module;
+	struct list_head list;
+};
+
+static LIST_HEAD(bpf_trace_modules);
+static DEFINE_MUTEX(bpf_module_mutex);
+
+static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name)
+{
+	struct bpf_raw_event_map *btp, *ret = NULL;
+	struct bpf_trace_module *btm;
+	unsigned int i;
+
+	mutex_lock(&bpf_module_mutex);
+	list_for_each_entry(btm, &bpf_trace_modules, list) {
+		for (i = 0; i < btm->module->num_bpf_raw_events; ++i) {
+			btp = &btm->module->bpf_raw_events[i];
+			if (!strcmp(btp->tp->name, name)) {
+				if (try_module_get(btm->module))
+					ret = btp;
+				goto out;
+			}
+		}
+	}
+out:
+	mutex_unlock(&bpf_module_mutex);
+	return ret;
+}
+#else
+static struct bpf_raw_event_map *bpf_get_raw_tracepoint_module(const char *name)
+{
+	return NULL;
+}
+#endif /* CONFIG_MODULES */
+
+u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
+u64 bpf_get_stack(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
+
+static int bpf_btf_printf_prepare(struct btf_ptr *ptr, u32 btf_ptr_size,
+				  u64 flags, const struct btf **btf,
+				  s32 *btf_id);
+static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx);
+static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx);
+
+/**
+ * trace_call_bpf - invoke BPF program
+ * @call: tracepoint event
+ * @ctx: opaque context pointer
+ *
+ * kprobe handlers execute BPF programs via this helper.
+ * Can be used from static tracepoints in the future.
+ *
+ * Return: BPF programs always return an integer which is interpreted by
+ * kprobe handler as:
+ * 0 - return from kprobe (event is filtered out)
+ * 1 - store kprobe event into ring buffer
+ * Other values are reserved and currently alias to 1
+ */
+unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
+{
+	unsigned int ret;
+
+	cant_sleep();
+
+	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
+		/*
+		 * since some bpf program is already running on this cpu,
+		 * don't call into another bpf program (same or different)
+		 * and don't send kprobe event into ring-buffer,
+		 * so return zero here
+		 */
+		ret = 0;
+		goto out;
+	}
+
+	/*
+	 * Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock
+	 * to all call sites, we did a bpf_prog_array_valid() there to check
+	 * whether call->prog_array is empty or not, which is
+	 * a heuristic to speed up execution.
+	 *
+	 * If bpf_prog_array_valid() fetched prog_array was
+	 * non-NULL, we go into trace_call_bpf() and do the actual
+	 * proper rcu_dereference() under RCU lock.
+	 * If it turns out that prog_array is NULL then, we bail out.
+	 * For the opposite, if the bpf_prog_array_valid() fetched pointer
+	 * was NULL, you'll skip the prog_array with the risk of missing
+	 * out of events when it was updated in between this and the
+	 * rcu_dereference() which is accepted risk.
+	 */
+	rcu_read_lock();
+	ret = bpf_prog_run_array(rcu_dereference(call->prog_array),
+				 ctx, bpf_prog_run);
+	rcu_read_unlock();
+
+ out:
+	__this_cpu_dec(bpf_prog_active);
+
+	return ret;
+}
+
+#ifdef CONFIG_BPF_KPROBE_OVERRIDE
+BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc)
+{
+	regs_set_return_value(regs, rc);
+	override_function_with_return(regs);
+	return 0;
+}
+
+static const struct bpf_func_proto bpf_override_return_proto = {
+	.func		= bpf_override_return,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+};
+#endif
+
+static __always_inline int
+bpf_probe_read_user_common(void *dst, u32 size, const void __user *unsafe_ptr)
+{
+	int ret;
+
+	ret = copy_from_user_nofault(dst, unsafe_ptr, size);
+	if (unlikely(ret < 0))
+		memset(dst, 0, size);
+	return ret;
+}
+
+BPF_CALL_3(bpf_probe_read_user, void *, dst, u32, size,
+	   const void __user *, unsafe_ptr)
+{
+	return bpf_probe_read_user_common(dst, size, unsafe_ptr);
+}
+
+const struct bpf_func_proto bpf_probe_read_user_proto = {
+	.func		= bpf_probe_read_user,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+static __always_inline int
+bpf_probe_read_user_str_common(void *dst, u32 size,
+			       const void __user *unsafe_ptr)
+{
+	int ret;
+
+	/*
+	 * NB: We rely on strncpy_from_user() not copying junk past the NUL
+	 * terminator into `dst`.
+	 *
+	 * strncpy_from_user() does long-sized strides in the fast path. If the
+	 * strncpy does not mask out the bytes after the NUL in `unsafe_ptr`,
+	 * then there could be junk after the NUL in `dst`. If user takes `dst`
+	 * and keys a hash map with it, then semantically identical strings can
+	 * occupy multiple entries in the map.
+	 */
+	ret = strncpy_from_user_nofault(dst, unsafe_ptr, size);
+	if (unlikely(ret < 0))
+		memset(dst, 0, size);
+	return ret;
+}
+
+BPF_CALL_3(bpf_probe_read_user_str, void *, dst, u32, size,
+	   const void __user *, unsafe_ptr)
+{
+	return bpf_probe_read_user_str_common(dst, size, unsafe_ptr);
+}
+
+const struct bpf_func_proto bpf_probe_read_user_str_proto = {
+	.func		= bpf_probe_read_user_str,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+static __always_inline int
+bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr)
+{
+	int ret;
+
+	ret = copy_from_kernel_nofault(dst, unsafe_ptr, size);
+	if (unlikely(ret < 0))
+		memset(dst, 0, size);
+	return ret;
+}
+
+BPF_CALL_3(bpf_probe_read_kernel, void *, dst, u32, size,
+	   const void *, unsafe_ptr)
+{
+	return bpf_probe_read_kernel_common(dst, size, unsafe_ptr);
+}
+
+const struct bpf_func_proto bpf_probe_read_kernel_proto = {
+	.func		= bpf_probe_read_kernel,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+static __always_inline int
+bpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr)
+{
+	int ret;
+
+	/*
+	 * The strncpy_from_kernel_nofault() call will likely not fill the
+	 * entire buffer, but that's okay in this circumstance as we're probing
+	 * arbitrary memory anyway similar to bpf_probe_read_*() and might
+	 * as well probe the stack. Thus, memory is explicitly cleared
+	 * only in error case, so that improper users ignoring return
+	 * code altogether don't copy garbage; otherwise length of string
+	 * is returned that can be used for bpf_perf_event_output() et al.
+	 */
+	ret = strncpy_from_kernel_nofault(dst, unsafe_ptr, size);
+	if (unlikely(ret < 0))
+		memset(dst, 0, size);
+	return ret;
+}
+
+BPF_CALL_3(bpf_probe_read_kernel_str, void *, dst, u32, size,
+	   const void *, unsafe_ptr)
+{
+	return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr);
+}
+
+const struct bpf_func_proto bpf_probe_read_kernel_str_proto = {
+	.func		= bpf_probe_read_kernel_str,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+BPF_CALL_3(bpf_probe_read_compat, void *, dst, u32, size,
+	   const void *, unsafe_ptr)
+{
+	if ((unsigned long)unsafe_ptr < TASK_SIZE) {
+		return bpf_probe_read_user_common(dst, size,
+				(__force void __user *)unsafe_ptr);
+	}
+	return bpf_probe_read_kernel_common(dst, size, unsafe_ptr);
+}
+
+static const struct bpf_func_proto bpf_probe_read_compat_proto = {
+	.func		= bpf_probe_read_compat,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_3(bpf_probe_read_compat_str, void *, dst, u32, size,
+	   const void *, unsafe_ptr)
+{
+	if ((unsigned long)unsafe_ptr < TASK_SIZE) {
+		return bpf_probe_read_user_str_common(dst, size,
+				(__force void __user *)unsafe_ptr);
+	}
+	return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr);
+}
+
+static const struct bpf_func_proto bpf_probe_read_compat_str_proto = {
+	.func		= bpf_probe_read_compat_str,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg3_type	= ARG_ANYTHING,
+};
+#endif /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */
+
+BPF_CALL_3(bpf_probe_write_user, void __user *, unsafe_ptr, const void *, src,
+	   u32, size)
+{
+	/*
+	 * Ensure we're in user context which is safe for the helper to
+	 * run. This helper has no business in a kthread.
+	 *
+	 * access_ok() should prevent writing to non-user memory, but in
+	 * some situations (nommu, temporary switch, etc) access_ok() does
+	 * not provide enough validation, hence the check on KERNEL_DS.
+	 *
+	 * nmi_uaccess_okay() ensures the probe is not run in an interim
+	 * state, when the task or mm are switched. This is specifically
+	 * required to prevent the use of temporary mm.
+	 */
+
+	if (unlikely(in_interrupt() ||
+		     current->flags & (PF_KTHREAD | PF_EXITING)))
+		return -EPERM;
+	if (unlikely(!nmi_uaccess_okay()))
+		return -EPERM;
+
+	return copy_to_user_nofault(unsafe_ptr, src, size);
+}
+
+static const struct bpf_func_proto bpf_probe_write_user_proto = {
+	.func		= bpf_probe_write_user,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_ANYTHING,
+	.arg2_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg3_type	= ARG_CONST_SIZE,
+};
+
+static const struct bpf_func_proto *bpf_get_probe_write_proto(void)
+{
+	if (!capable(CAP_SYS_ADMIN))
+		return NULL;
+
+	pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!",
+			    current->comm, task_pid_nr(current));
+
+	return &bpf_probe_write_user_proto;
+}
+
+static DEFINE_RAW_SPINLOCK(trace_printk_lock);
+
+#define MAX_TRACE_PRINTK_VARARGS	3
+#define BPF_TRACE_PRINTK_SIZE		1024
+
+BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
+	   u64, arg2, u64, arg3)
+{
+	u64 args[MAX_TRACE_PRINTK_VARARGS] = { arg1, arg2, arg3 };
+	u32 *bin_args;
+	static char buf[BPF_TRACE_PRINTK_SIZE];
+	unsigned long flags;
+	int ret;
+
+	ret = bpf_bprintf_prepare(fmt, fmt_size, args, &bin_args,
+				  MAX_TRACE_PRINTK_VARARGS);
+	if (ret < 0)
+		return ret;
+
+	raw_spin_lock_irqsave(&trace_printk_lock, flags);
+	ret = bstr_printf(buf, sizeof(buf), fmt, bin_args);
+
+	trace_bpf_trace_printk(buf);
+	raw_spin_unlock_irqrestore(&trace_printk_lock, flags);
+
+	bpf_bprintf_cleanup();
+
+	return ret;
+}
+
+static const struct bpf_func_proto bpf_trace_printk_proto = {
+	.func		= bpf_trace_printk,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg2_type	= ARG_CONST_SIZE,
+};
+
+static void __set_printk_clr_event(void)
+{
+	/*
+	 * This program might be calling bpf_trace_printk,
+	 * so enable the associated bpf_trace/bpf_trace_printk event.
+	 * Repeat this each time as it is possible a user has
+	 * disabled bpf_trace_printk events.  By loading a program
+	 * calling bpf_trace_printk() however the user has expressed
+	 * the intent to see such events.
+	 */
+	if (trace_set_clr_event("bpf_trace", "bpf_trace_printk", 1))
+		pr_warn_ratelimited("could not enable bpf_trace_printk events");
+}
+
+const struct bpf_func_proto *bpf_get_trace_printk_proto(void)
+{
+	__set_printk_clr_event();
+	return &bpf_trace_printk_proto;
+}
+
+BPF_CALL_4(bpf_trace_vprintk, char *, fmt, u32, fmt_size, const void *, data,
+	   u32, data_len)
+{
+	static char buf[BPF_TRACE_PRINTK_SIZE];
+	unsigned long flags;
+	int ret, num_args;
+	u32 *bin_args;
+
+	if (data_len & 7 || data_len > MAX_BPRINTF_VARARGS * 8 ||
+	    (data_len && !data))
+		return -EINVAL;
+	num_args = data_len / 8;
+
+	ret = bpf_bprintf_prepare(fmt, fmt_size, data, &bin_args, num_args);
+	if (ret < 0)
+		return ret;
+
+	raw_spin_lock_irqsave(&trace_printk_lock, flags);
+	ret = bstr_printf(buf, sizeof(buf), fmt, bin_args);
+
+	trace_bpf_trace_printk(buf);
+	raw_spin_unlock_irqrestore(&trace_printk_lock, flags);
+
+	bpf_bprintf_cleanup();
+
+	return ret;
+}
+
+static const struct bpf_func_proto bpf_trace_vprintk_proto = {
+	.func		= bpf_trace_vprintk,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg2_type	= ARG_CONST_SIZE,
+	.arg3_type	= ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY,
+	.arg4_type	= ARG_CONST_SIZE_OR_ZERO,
+};
+
+const struct bpf_func_proto *bpf_get_trace_vprintk_proto(void)
+{
+	__set_printk_clr_event();
+	return &bpf_trace_vprintk_proto;
+}
+
+BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size,
+	   const void *, data, u32, data_len)
+{
+	int err, num_args;
+	u32 *bin_args;
+
+	if (data_len & 7 || data_len > MAX_BPRINTF_VARARGS * 8 ||
+	    (data_len && !data))
+		return -EINVAL;
+	num_args = data_len / 8;
+
+	err = bpf_bprintf_prepare(fmt, fmt_size, data, &bin_args, num_args);
+	if (err < 0)
+		return err;
+
+	seq_bprintf(m, fmt, bin_args);
+
+	bpf_bprintf_cleanup();
+
+	return seq_has_overflowed(m) ? -EOVERFLOW : 0;
+}
+
+BTF_ID_LIST_SINGLE(btf_seq_file_ids, struct, seq_file)
+
+static const struct bpf_func_proto bpf_seq_printf_proto = {
+	.func		= bpf_seq_printf,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_BTF_ID,
+	.arg1_btf_id	= &btf_seq_file_ids[0],
+	.arg2_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg3_type	= ARG_CONST_SIZE,
+	.arg4_type      = ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY,
+	.arg5_type      = ARG_CONST_SIZE_OR_ZERO,
+};
+
+BPF_CALL_3(bpf_seq_write, struct seq_file *, m, const void *, data, u32, len)
+{
+	return seq_write(m, data, len) ? -EOVERFLOW : 0;
+}
+
+static const struct bpf_func_proto bpf_seq_write_proto = {
+	.func		= bpf_seq_write,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_BTF_ID,
+	.arg1_btf_id	= &btf_seq_file_ids[0],
+	.arg2_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg3_type	= ARG_CONST_SIZE_OR_ZERO,
+};
+
+BPF_CALL_4(bpf_seq_printf_btf, struct seq_file *, m, struct btf_ptr *, ptr,
+	   u32, btf_ptr_size, u64, flags)
+{
+	const struct btf *btf;
+	s32 btf_id;
+	int ret;
+
+	ret = bpf_btf_printf_prepare(ptr, btf_ptr_size, flags, &btf, &btf_id);
+	if (ret)
+		return ret;
+
+	return btf_type_seq_show_flags(btf, btf_id, ptr->ptr, m, flags);
+}
+
+static const struct bpf_func_proto bpf_seq_printf_btf_proto = {
+	.func		= bpf_seq_printf_btf,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_BTF_ID,
+	.arg1_btf_id	= &btf_seq_file_ids[0],
+	.arg2_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg3_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+static __always_inline int
+get_map_perf_counter(struct bpf_map *map, u64 flags,
+		     u64 *value, u64 *enabled, u64 *running)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	unsigned int cpu = smp_processor_id();
+	u64 index = flags & BPF_F_INDEX_MASK;
+	struct bpf_event_entry *ee;
+
+	if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
+		return -EINVAL;
+	if (index == BPF_F_CURRENT_CPU)
+		index = cpu;
+	if (unlikely(index >= array->map.max_entries))
+		return -E2BIG;
+
+	ee = READ_ONCE(array->ptrs[index]);
+	if (!ee)
+		return -ENOENT;
+
+	return perf_event_read_local(ee->event, value, enabled, running);
+}
+
+BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
+{
+	u64 value = 0;
+	int err;
+
+	err = get_map_perf_counter(map, flags, &value, NULL, NULL);
+	/*
+	 * this api is ugly since we miss [-22..-2] range of valid
+	 * counter values, but that's uapi
+	 */
+	if (err)
+		return err;
+	return value;
+}
+
+static const struct bpf_func_proto bpf_perf_event_read_proto = {
+	.func		= bpf_perf_event_read,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_4(bpf_perf_event_read_value, struct bpf_map *, map, u64, flags,
+	   struct bpf_perf_event_value *, buf, u32, size)
+{
+	int err = -EINVAL;
+
+	if (unlikely(size != sizeof(struct bpf_perf_event_value)))
+		goto clear;
+	err = get_map_perf_counter(map, flags, &buf->counter, &buf->enabled,
+				   &buf->running);
+	if (unlikely(err))
+		goto clear;
+	return 0;
+clear:
+	memset(buf, 0, size);
+	return err;
+}
+
+static const struct bpf_func_proto bpf_perf_event_read_value_proto = {
+	.func		= bpf_perf_event_read_value,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg4_type	= ARG_CONST_SIZE,
+};
+
+static __always_inline u64
+__bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,
+			u64 flags, struct perf_sample_data *sd)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	unsigned int cpu = smp_processor_id();
+	u64 index = flags & BPF_F_INDEX_MASK;
+	struct bpf_event_entry *ee;
+	struct perf_event *event;
+
+	if (index == BPF_F_CURRENT_CPU)
+		index = cpu;
+	if (unlikely(index >= array->map.max_entries))
+		return -E2BIG;
+
+	ee = READ_ONCE(array->ptrs[index]);
+	if (!ee)
+		return -ENOENT;
+
+	event = ee->event;
+	if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE ||
+		     event->attr.config != PERF_COUNT_SW_BPF_OUTPUT))
+		return -EINVAL;
+
+	if (unlikely(event->oncpu != cpu))
+		return -EOPNOTSUPP;
+
+	return perf_event_output(event, sd, regs);
+}
+
+/*
+ * Support executing tracepoints in normal, irq, and nmi context that each call
+ * bpf_perf_event_output
+ */
+struct bpf_trace_sample_data {
+	struct perf_sample_data sds[3];
+};
+
+static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_trace_sds);
+static DEFINE_PER_CPU(int, bpf_trace_nest_level);
+BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map,
+	   u64, flags, void *, data, u64, size)
+{
+	struct bpf_trace_sample_data *sds;
+	struct perf_raw_record raw = {
+		.frag = {
+			.size = size,
+			.data = data,
+		},
+	};
+	struct perf_sample_data *sd;
+	int nest_level, err;
+
+	preempt_disable();
+	sds = this_cpu_ptr(&bpf_trace_sds);
+	nest_level = this_cpu_inc_return(bpf_trace_nest_level);
+
+	if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(sds->sds))) {
+		err = -EBUSY;
+		goto out;
+	}
+
+	sd = &sds->sds[nest_level - 1];
+
+	if (unlikely(flags & ~(BPF_F_INDEX_MASK))) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	perf_sample_data_init(sd, 0, 0);
+	sd->raw = &raw;
+	sd->sample_flags |= PERF_SAMPLE_RAW;
+
+	err = __bpf_perf_event_output(regs, map, flags, sd);
+out:
+	this_cpu_dec(bpf_trace_nest_level);
+	preempt_enable();
+	return err;
+}
+
+static const struct bpf_func_proto bpf_perf_event_output_proto = {
+	.func		= bpf_perf_event_output,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_CONST_MAP_PTR,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg5_type	= ARG_CONST_SIZE_OR_ZERO,
+};
+
+static DEFINE_PER_CPU(int, bpf_event_output_nest_level);
+struct bpf_nested_pt_regs {
+	struct pt_regs regs[3];
+};
+static DEFINE_PER_CPU(struct bpf_nested_pt_regs, bpf_pt_regs);
+static DEFINE_PER_CPU(struct bpf_trace_sample_data, bpf_misc_sds);
+
+u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
+		     void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
+{
+	struct perf_raw_frag frag = {
+		.copy		= ctx_copy,
+		.size		= ctx_size,
+		.data		= ctx,
+	};
+	struct perf_raw_record raw = {
+		.frag = {
+			{
+				.next	= ctx_size ? &frag : NULL,
+			},
+			.size	= meta_size,
+			.data	= meta,
+		},
+	};
+	struct perf_sample_data *sd;
+	struct pt_regs *regs;
+	int nest_level;
+	u64 ret;
+
+	preempt_disable();
+	nest_level = this_cpu_inc_return(bpf_event_output_nest_level);
+
+	if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bpf_misc_sds.sds))) {
+		ret = -EBUSY;
+		goto out;
+	}
+	sd = this_cpu_ptr(&bpf_misc_sds.sds[nest_level - 1]);
+	regs = this_cpu_ptr(&bpf_pt_regs.regs[nest_level - 1]);
+
+	perf_fetch_caller_regs(regs);
+	perf_sample_data_init(sd, 0, 0);
+	sd->raw = &raw;
+	sd->sample_flags |= PERF_SAMPLE_RAW;
+
+	ret = __bpf_perf_event_output(regs, map, flags, sd);
+out:
+	this_cpu_dec(bpf_event_output_nest_level);
+	preempt_enable();
+	return ret;
+}
+
+BPF_CALL_0(bpf_get_current_task)
+{
+	return (long) current;
+}
+
+const struct bpf_func_proto bpf_get_current_task_proto = {
+	.func		= bpf_get_current_task,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+};
+
+BPF_CALL_0(bpf_get_current_task_btf)
+{
+	return (unsigned long) current;
+}
+
+const struct bpf_func_proto bpf_get_current_task_btf_proto = {
+	.func		= bpf_get_current_task_btf,
+	.gpl_only	= true,
+	.ret_type	= RET_PTR_TO_BTF_ID,
+	.ret_btf_id	= &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
+};
+
+BPF_CALL_1(bpf_task_pt_regs, struct task_struct *, task)
+{
+	return (unsigned long) task_pt_regs(task);
+}
+
+BTF_ID_LIST(bpf_task_pt_regs_ids)
+BTF_ID(struct, pt_regs)
+
+const struct bpf_func_proto bpf_task_pt_regs_proto = {
+	.func		= bpf_task_pt_regs,
+	.gpl_only	= true,
+	.arg1_type	= ARG_PTR_TO_BTF_ID,
+	.arg1_btf_id	= &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
+	.ret_type	= RET_PTR_TO_BTF_ID,
+	.ret_btf_id	= &bpf_task_pt_regs_ids[0],
+};
+
+BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx)
+{
+	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	struct cgroup *cgrp;
+
+	if (unlikely(idx >= array->map.max_entries))
+		return -E2BIG;
+
+	cgrp = READ_ONCE(array->ptrs[idx]);
+	if (unlikely(!cgrp))
+		return -EAGAIN;
+
+	return task_under_cgroup_hierarchy(current, cgrp);
+}
+
+static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = {
+	.func           = bpf_current_task_under_cgroup,
+	.gpl_only       = false,
+	.ret_type       = RET_INTEGER,
+	.arg1_type      = ARG_CONST_MAP_PTR,
+	.arg2_type      = ARG_ANYTHING,
+};
+
+struct send_signal_irq_work {
+	struct irq_work irq_work;
+	struct task_struct *task;
+	u32 sig;
+	enum pid_type type;
+};
+
+static DEFINE_PER_CPU(struct send_signal_irq_work, send_signal_work);
+
+static void do_bpf_send_signal(struct irq_work *entry)
+{
+	struct send_signal_irq_work *work;
+
+	work = container_of(entry, struct send_signal_irq_work, irq_work);
+	group_send_sig_info(work->sig, SEND_SIG_PRIV, work->task, work->type);
+	put_task_struct(work->task);
+}
+
+static int bpf_send_signal_common(u32 sig, enum pid_type type)
+{
+	struct send_signal_irq_work *work = NULL;
+
+	/* Similar to bpf_probe_write_user, task needs to be
+	 * in a sound condition and kernel memory access be
+	 * permitted in order to send signal to the current
+	 * task.
+	 */
+	if (unlikely(current->flags & (PF_KTHREAD | PF_EXITING)))
+		return -EPERM;
+	if (unlikely(!nmi_uaccess_okay()))
+		return -EPERM;
+	/* Task should not be pid=1 to avoid kernel panic. */
+	if (unlikely(is_global_init(current)))
+		return -EPERM;
+
+	if (irqs_disabled()) {
+		/* Do an early check on signal validity. Otherwise,
+		 * the error is lost in deferred irq_work.
+		 */
+		if (unlikely(!valid_signal(sig)))
+			return -EINVAL;
+
+		work = this_cpu_ptr(&send_signal_work);
+		if (irq_work_is_busy(&work->irq_work))
+			return -EBUSY;
+
+		/* Add the current task, which is the target of sending signal,
+		 * to the irq_work. The current task may change when queued
+		 * irq works get executed.
+		 */
+		work->task = get_task_struct(current);
+		work->sig = sig;
+		work->type = type;
+		irq_work_queue(&work->irq_work);
+		return 0;
+	}
+
+	return group_send_sig_info(sig, SEND_SIG_PRIV, current, type);
+}
+
+BPF_CALL_1(bpf_send_signal, u32, sig)
+{
+	return bpf_send_signal_common(sig, PIDTYPE_TGID);
+}
+
+static const struct bpf_func_proto bpf_send_signal_proto = {
+	.func		= bpf_send_signal,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_1(bpf_send_signal_thread, u32, sig)
+{
+	return bpf_send_signal_common(sig, PIDTYPE_PID);
+}
+
+static const struct bpf_func_proto bpf_send_signal_thread_proto = {
+	.func		= bpf_send_signal_thread,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_3(bpf_d_path, struct path *, path, char *, buf, u32, sz)
+{
+	struct path copy;
+	long len;
+	char *p;
+
+	if (!sz)
+		return 0;
+
+	/*
+	 * The path pointer is verified as trusted and safe to use,
+	 * but let's double check it's valid anyway to workaround
+	 * potentially broken verifier.
+	 */
+	len = copy_from_kernel_nofault(&copy, path, sizeof(*path));
+	if (len < 0)
+		return len;
+
+	p = d_path(&copy, buf, sz);
+	if (IS_ERR(p)) {
+		len = PTR_ERR(p);
+	} else {
+		len = buf + sz - p;
+		memmove(buf, p, len);
+	}
+
+	return len;
+}
+
+BTF_SET_START(btf_allowlist_d_path)
+#ifdef CONFIG_SECURITY
+BTF_ID(func, security_file_permission)
+BTF_ID(func, security_inode_getattr)
+BTF_ID(func, security_file_open)
+#endif
+#ifdef CONFIG_SECURITY_PATH
+BTF_ID(func, security_path_truncate)
+#endif
+BTF_ID(func, vfs_truncate)
+BTF_ID(func, vfs_fallocate)
+BTF_ID(func, dentry_open)
+BTF_ID(func, vfs_getattr)
+BTF_ID(func, filp_close)
+BTF_SET_END(btf_allowlist_d_path)
+
+static bool bpf_d_path_allowed(const struct bpf_prog *prog)
+{
+	if (prog->type == BPF_PROG_TYPE_TRACING &&
+	    prog->expected_attach_type == BPF_TRACE_ITER)
+		return true;
+
+	if (prog->type == BPF_PROG_TYPE_LSM)
+		return bpf_lsm_is_sleepable_hook(prog->aux->attach_btf_id);
+
+	return btf_id_set_contains(&btf_allowlist_d_path,
+				   prog->aux->attach_btf_id);
+}
+
+BTF_ID_LIST_SINGLE(bpf_d_path_btf_ids, struct, path)
+
+static const struct bpf_func_proto bpf_d_path_proto = {
+	.func		= bpf_d_path,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_BTF_ID,
+	.arg1_btf_id	= &bpf_d_path_btf_ids[0],
+	.arg2_type	= ARG_PTR_TO_MEM,
+	.arg3_type	= ARG_CONST_SIZE_OR_ZERO,
+	.allowed	= bpf_d_path_allowed,
+};
+
+#define BTF_F_ALL	(BTF_F_COMPACT  | BTF_F_NONAME | \
+			 BTF_F_PTR_RAW | BTF_F_ZERO)
+
+static int bpf_btf_printf_prepare(struct btf_ptr *ptr, u32 btf_ptr_size,
+				  u64 flags, const struct btf **btf,
+				  s32 *btf_id)
+{
+	const struct btf_type *t;
+
+	if (unlikely(flags & ~(BTF_F_ALL)))
+		return -EINVAL;
+
+	if (btf_ptr_size != sizeof(struct btf_ptr))
+		return -EINVAL;
+
+	*btf = bpf_get_btf_vmlinux();
+
+	if (IS_ERR_OR_NULL(*btf))
+		return IS_ERR(*btf) ? PTR_ERR(*btf) : -EINVAL;
+
+	if (ptr->type_id > 0)
+		*btf_id = ptr->type_id;
+	else
+		return -EINVAL;
+
+	if (*btf_id > 0)
+		t = btf_type_by_id(*btf, *btf_id);
+	if (*btf_id <= 0 || !t)
+		return -ENOENT;
+
+	return 0;
+}
+
+BPF_CALL_5(bpf_snprintf_btf, char *, str, u32, str_size, struct btf_ptr *, ptr,
+	   u32, btf_ptr_size, u64, flags)
+{
+	const struct btf *btf;
+	s32 btf_id;
+	int ret;
+
+	ret = bpf_btf_printf_prepare(ptr, btf_ptr_size, flags, &btf, &btf_id);
+	if (ret)
+		return ret;
+
+	return btf_type_snprintf_show(btf, btf_id, ptr->ptr, str, str_size,
+				      flags);
+}
+
+const struct bpf_func_proto bpf_snprintf_btf_proto = {
+	.func		= bpf_snprintf_btf,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_MEM,
+	.arg2_type	= ARG_CONST_SIZE,
+	.arg3_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg4_type	= ARG_CONST_SIZE,
+	.arg5_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_1(bpf_get_func_ip_tracing, void *, ctx)
+{
+	/* This helper call is inlined by verifier. */
+	return ((u64 *)ctx)[-2];
+}
+
+static const struct bpf_func_proto bpf_get_func_ip_proto_tracing = {
+	.func		= bpf_get_func_ip_tracing,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+};
+
+#ifdef CONFIG_X86_KERNEL_IBT
+static unsigned long get_entry_ip(unsigned long fentry_ip)
+{
+	u32 instr;
+
+	/* Being extra safe in here in case entry ip is on the page-edge. */
+	if (get_kernel_nofault(instr, (u32 *) fentry_ip - 1))
+		return fentry_ip;
+	if (is_endbr(instr))
+		fentry_ip -= ENDBR_INSN_SIZE;
+	return fentry_ip;
+}
+#else
+#define get_entry_ip(fentry_ip) fentry_ip
+#endif
+
+BPF_CALL_1(bpf_get_func_ip_kprobe, struct pt_regs *, regs)
+{
+	struct kprobe *kp = kprobe_running();
+
+	if (!kp || !(kp->flags & KPROBE_FLAG_ON_FUNC_ENTRY))
+		return 0;
+
+	return get_entry_ip((uintptr_t)kp->addr);
+}
+
+static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe = {
+	.func		= bpf_get_func_ip_kprobe,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+};
+
+BPF_CALL_1(bpf_get_func_ip_kprobe_multi, struct pt_regs *, regs)
+{
+	return bpf_kprobe_multi_entry_ip(current->bpf_ctx);
+}
+
+static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe_multi = {
+	.func		= bpf_get_func_ip_kprobe_multi,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+};
+
+BPF_CALL_1(bpf_get_attach_cookie_kprobe_multi, struct pt_regs *, regs)
+{
+	return bpf_kprobe_multi_cookie(current->bpf_ctx);
+}
+
+static const struct bpf_func_proto bpf_get_attach_cookie_proto_kmulti = {
+	.func		= bpf_get_attach_cookie_kprobe_multi,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+};
+
+BPF_CALL_1(bpf_get_attach_cookie_trace, void *, ctx)
+{
+	struct bpf_trace_run_ctx *run_ctx;
+
+	run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx);
+	return run_ctx->bpf_cookie;
+}
+
+static const struct bpf_func_proto bpf_get_attach_cookie_proto_trace = {
+	.func		= bpf_get_attach_cookie_trace,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+};
+
+BPF_CALL_1(bpf_get_attach_cookie_pe, struct bpf_perf_event_data_kern *, ctx)
+{
+	return ctx->event->bpf_cookie;
+}
+
+static const struct bpf_func_proto bpf_get_attach_cookie_proto_pe = {
+	.func		= bpf_get_attach_cookie_pe,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+};
+
+BPF_CALL_1(bpf_get_attach_cookie_tracing, void *, ctx)
+{
+	struct bpf_trace_run_ctx *run_ctx;
+
+	run_ctx = container_of(current->bpf_ctx, struct bpf_trace_run_ctx, run_ctx);
+	return run_ctx->bpf_cookie;
+}
+
+static const struct bpf_func_proto bpf_get_attach_cookie_proto_tracing = {
+	.func		= bpf_get_attach_cookie_tracing,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+};
+
+BPF_CALL_3(bpf_get_branch_snapshot, void *, buf, u32, size, u64, flags)
+{
+#ifndef CONFIG_X86
+	return -ENOENT;
+#else
+	static const u32 br_entry_size = sizeof(struct perf_branch_entry);
+	u32 entry_cnt = size / br_entry_size;
+
+	entry_cnt = static_call(perf_snapshot_branch_stack)(buf, entry_cnt);
+
+	if (unlikely(flags))
+		return -EINVAL;
+
+	if (!entry_cnt)
+		return -ENOENT;
+
+	return entry_cnt * br_entry_size;
+#endif
+}
+
+static const struct bpf_func_proto bpf_get_branch_snapshot_proto = {
+	.func		= bpf_get_branch_snapshot,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
+};
+
+BPF_CALL_3(get_func_arg, void *, ctx, u32, n, u64 *, value)
+{
+	/* This helper call is inlined by verifier. */
+	u64 nr_args = ((u64 *)ctx)[-1];
+
+	if ((u64) n >= nr_args)
+		return -EINVAL;
+	*value = ((u64 *)ctx)[n];
+	return 0;
+}
+
+static const struct bpf_func_proto bpf_get_func_arg_proto = {
+	.func		= get_func_arg,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_PTR_TO_LONG,
+};
+
+BPF_CALL_2(get_func_ret, void *, ctx, u64 *, value)
+{
+	/* This helper call is inlined by verifier. */
+	u64 nr_args = ((u64 *)ctx)[-1];
+
+	*value = ((u64 *)ctx)[nr_args];
+	return 0;
+}
+
+static const struct bpf_func_proto bpf_get_func_ret_proto = {
+	.func		= get_func_ret,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_LONG,
+};
+
+BPF_CALL_1(get_func_arg_cnt, void *, ctx)
+{
+	/* This helper call is inlined by verifier. */
+	return ((u64 *)ctx)[-1];
+}
+
+static const struct bpf_func_proto bpf_get_func_arg_cnt_proto = {
+	.func		= get_func_arg_cnt,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+};
+
+#ifdef CONFIG_KEYS
+__diag_push();
+__diag_ignore_all("-Wmissing-prototypes",
+		  "kfuncs which will be used in BPF programs");
+
+/**
+ * bpf_lookup_user_key - lookup a key by its serial
+ * @serial: key handle serial number
+ * @flags: lookup-specific flags
+ *
+ * Search a key with a given *serial* and the provided *flags*.
+ * If found, increment the reference count of the key by one, and
+ * return it in the bpf_key structure.
+ *
+ * The bpf_key structure must be passed to bpf_key_put() when done
+ * with it, so that the key reference count is decremented and the
+ * bpf_key structure is freed.
+ *
+ * Permission checks are deferred to the time the key is used by
+ * one of the available key-specific kfuncs.
+ *
+ * Set *flags* with KEY_LOOKUP_CREATE, to attempt creating a requested
+ * special keyring (e.g. session keyring), if it doesn't yet exist.
+ * Set *flags* with KEY_LOOKUP_PARTIAL, to lookup a key without waiting
+ * for the key construction, and to retrieve uninstantiated keys (keys
+ * without data attached to them).
+ *
+ * Return: a bpf_key pointer with a valid key pointer if the key is found, a
+ *         NULL pointer otherwise.
+ */
+struct bpf_key *bpf_lookup_user_key(u32 serial, u64 flags)
+{
+	key_ref_t key_ref;
+	struct bpf_key *bkey;
+
+	if (flags & ~KEY_LOOKUP_ALL)
+		return NULL;
+
+	/*
+	 * Permission check is deferred until the key is used, as the
+	 * intent of the caller is unknown here.
+	 */
+	key_ref = lookup_user_key(serial, flags, KEY_DEFER_PERM_CHECK);
+	if (IS_ERR(key_ref))
+		return NULL;
+
+	bkey = kmalloc(sizeof(*bkey), GFP_KERNEL);
+	if (!bkey) {
+		key_put(key_ref_to_ptr(key_ref));
+		return NULL;
+	}
+
+	bkey->key = key_ref_to_ptr(key_ref);
+	bkey->has_ref = true;
+
+	return bkey;
+}
+
+/**
+ * bpf_lookup_system_key - lookup a key by a system-defined ID
+ * @id: key ID
+ *
+ * Obtain a bpf_key structure with a key pointer set to the passed key ID.
+ * The key pointer is marked as invalid, to prevent bpf_key_put() from
+ * attempting to decrement the key reference count on that pointer. The key
+ * pointer set in such way is currently understood only by
+ * verify_pkcs7_signature().
+ *
+ * Set *id* to one of the values defined in include/linux/verification.h:
+ * 0 for the primary keyring (immutable keyring of system keys);
+ * VERIFY_USE_SECONDARY_KEYRING for both the primary and secondary keyring
+ * (where keys can be added only if they are vouched for by existing keys
+ * in those keyrings); VERIFY_USE_PLATFORM_KEYRING for the platform
+ * keyring (primarily used by the integrity subsystem to verify a kexec'ed
+ * kerned image and, possibly, the initramfs signature).
+ *
+ * Return: a bpf_key pointer with an invalid key pointer set from the
+ *         pre-determined ID on success, a NULL pointer otherwise
+ */
+struct bpf_key *bpf_lookup_system_key(u64 id)
+{
+	struct bpf_key *bkey;
+
+	if (system_keyring_id_check(id) < 0)
+		return NULL;
+
+	bkey = kmalloc(sizeof(*bkey), GFP_ATOMIC);
+	if (!bkey)
+		return NULL;
+
+	bkey->key = (struct key *)(unsigned long)id;
+	bkey->has_ref = false;
+
+	return bkey;
+}
+
+/**
+ * bpf_key_put - decrement key reference count if key is valid and free bpf_key
+ * @bkey: bpf_key structure
+ *
+ * Decrement the reference count of the key inside *bkey*, if the pointer
+ * is valid, and free *bkey*.
+ */
+void bpf_key_put(struct bpf_key *bkey)
+{
+	if (bkey->has_ref)
+		key_put(bkey->key);
+
+	kfree(bkey);
+}
+
+#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
+/**
+ * bpf_verify_pkcs7_signature - verify a PKCS#7 signature
+ * @data_ptr: data to verify
+ * @sig_ptr: signature of the data
+ * @trusted_keyring: keyring with keys trusted for signature verification
+ *
+ * Verify the PKCS#7 signature *sig_ptr* against the supplied *data_ptr*
+ * with keys in a keyring referenced by *trusted_keyring*.
+ *
+ * Return: 0 on success, a negative value on error.
+ */
+int bpf_verify_pkcs7_signature(struct bpf_dynptr_kern *data_ptr,
+			       struct bpf_dynptr_kern *sig_ptr,
+			       struct bpf_key *trusted_keyring)
+{
+	int ret;
+
+	if (trusted_keyring->has_ref) {
+		/*
+		 * Do the permission check deferred in bpf_lookup_user_key().
+		 * See bpf_lookup_user_key() for more details.
+		 *
+		 * A call to key_task_permission() here would be redundant, as
+		 * it is already done by keyring_search() called by
+		 * find_asymmetric_key().
+		 */
+		ret = key_validate(trusted_keyring->key);
+		if (ret < 0)
+			return ret;
+	}
+
+	return verify_pkcs7_signature(data_ptr->data,
+				      bpf_dynptr_get_size(data_ptr),
+				      sig_ptr->data,
+				      bpf_dynptr_get_size(sig_ptr),
+				      trusted_keyring->key,
+				      VERIFYING_UNSPECIFIED_SIGNATURE, NULL,
+				      NULL);
+}
+#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
+
+__diag_pop();
+
+BTF_SET8_START(key_sig_kfunc_set)
+BTF_ID_FLAGS(func, bpf_lookup_user_key, KF_ACQUIRE | KF_RET_NULL | KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_lookup_system_key, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_key_put, KF_RELEASE)
+#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
+BTF_ID_FLAGS(func, bpf_verify_pkcs7_signature, KF_SLEEPABLE)
+#endif
+BTF_SET8_END(key_sig_kfunc_set)
+
+static const struct btf_kfunc_id_set bpf_key_sig_kfunc_set = {
+	.owner = THIS_MODULE,
+	.set = &key_sig_kfunc_set,
+};
+
+static int __init bpf_key_sig_kfuncs_init(void)
+{
+	return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING,
+					 &bpf_key_sig_kfunc_set);
+}
+
+late_initcall(bpf_key_sig_kfuncs_init);
+#endif /* CONFIG_KEYS */
+
+static const struct bpf_func_proto *
+bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	switch (func_id) {
+	case BPF_FUNC_map_lookup_elem:
+		return &bpf_map_lookup_elem_proto;
+	case BPF_FUNC_map_update_elem:
+		return &bpf_map_update_elem_proto;
+	case BPF_FUNC_map_delete_elem:
+		return &bpf_map_delete_elem_proto;
+	case BPF_FUNC_map_push_elem:
+		return &bpf_map_push_elem_proto;
+	case BPF_FUNC_map_pop_elem:
+		return &bpf_map_pop_elem_proto;
+	case BPF_FUNC_map_peek_elem:
+		return &bpf_map_peek_elem_proto;
+	case BPF_FUNC_map_lookup_percpu_elem:
+		return &bpf_map_lookup_percpu_elem_proto;
+	case BPF_FUNC_ktime_get_ns:
+		return &bpf_ktime_get_ns_proto;
+	case BPF_FUNC_ktime_get_boot_ns:
+		return &bpf_ktime_get_boot_ns_proto;
+	case BPF_FUNC_tail_call:
+		return &bpf_tail_call_proto;
+	case BPF_FUNC_get_current_pid_tgid:
+		return &bpf_get_current_pid_tgid_proto;
+	case BPF_FUNC_get_current_task:
+		return &bpf_get_current_task_proto;
+	case BPF_FUNC_get_current_task_btf:
+		return &bpf_get_current_task_btf_proto;
+	case BPF_FUNC_task_pt_regs:
+		return &bpf_task_pt_regs_proto;
+	case BPF_FUNC_get_current_uid_gid:
+		return &bpf_get_current_uid_gid_proto;
+	case BPF_FUNC_get_current_comm:
+		return &bpf_get_current_comm_proto;
+	case BPF_FUNC_trace_printk:
+		return bpf_get_trace_printk_proto();
+	case BPF_FUNC_get_smp_processor_id:
+		return &bpf_get_smp_processor_id_proto;
+	case BPF_FUNC_get_numa_node_id:
+		return &bpf_get_numa_node_id_proto;
+	case BPF_FUNC_perf_event_read:
+		return &bpf_perf_event_read_proto;
+	case BPF_FUNC_current_task_under_cgroup:
+		return &bpf_current_task_under_cgroup_proto;
+	case BPF_FUNC_get_prandom_u32:
+		return &bpf_get_prandom_u32_proto;
+	case BPF_FUNC_probe_write_user:
+		return security_locked_down(LOCKDOWN_BPF_WRITE_USER) < 0 ?
+		       NULL : bpf_get_probe_write_proto();
+	case BPF_FUNC_probe_read_user:
+		return &bpf_probe_read_user_proto;
+	case BPF_FUNC_probe_read_kernel:
+		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
+		       NULL : &bpf_probe_read_kernel_proto;
+	case BPF_FUNC_probe_read_user_str:
+		return &bpf_probe_read_user_str_proto;
+	case BPF_FUNC_probe_read_kernel_str:
+		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
+		       NULL : &bpf_probe_read_kernel_str_proto;
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+	case BPF_FUNC_probe_read:
+		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
+		       NULL : &bpf_probe_read_compat_proto;
+	case BPF_FUNC_probe_read_str:
+		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
+		       NULL : &bpf_probe_read_compat_str_proto;
+#endif
+#ifdef CONFIG_CGROUPS
+	case BPF_FUNC_get_current_cgroup_id:
+		return &bpf_get_current_cgroup_id_proto;
+	case BPF_FUNC_get_current_ancestor_cgroup_id:
+		return &bpf_get_current_ancestor_cgroup_id_proto;
+#endif
+	case BPF_FUNC_send_signal:
+		return &bpf_send_signal_proto;
+	case BPF_FUNC_send_signal_thread:
+		return &bpf_send_signal_thread_proto;
+	case BPF_FUNC_perf_event_read_value:
+		return &bpf_perf_event_read_value_proto;
+	case BPF_FUNC_get_ns_current_pid_tgid:
+		return &bpf_get_ns_current_pid_tgid_proto;
+	case BPF_FUNC_ringbuf_output:
+		return &bpf_ringbuf_output_proto;
+	case BPF_FUNC_ringbuf_reserve:
+		return &bpf_ringbuf_reserve_proto;
+	case BPF_FUNC_ringbuf_submit:
+		return &bpf_ringbuf_submit_proto;
+	case BPF_FUNC_ringbuf_discard:
+		return &bpf_ringbuf_discard_proto;
+	case BPF_FUNC_ringbuf_query:
+		return &bpf_ringbuf_query_proto;
+	case BPF_FUNC_jiffies64:
+		return &bpf_jiffies64_proto;
+	case BPF_FUNC_get_task_stack:
+		return &bpf_get_task_stack_proto;
+	case BPF_FUNC_copy_from_user:
+		return prog->aux->sleepable ? &bpf_copy_from_user_proto : NULL;
+	case BPF_FUNC_copy_from_user_task:
+		return prog->aux->sleepable ? &bpf_copy_from_user_task_proto : NULL;
+	case BPF_FUNC_snprintf_btf:
+		return &bpf_snprintf_btf_proto;
+	case BPF_FUNC_per_cpu_ptr:
+		return &bpf_per_cpu_ptr_proto;
+	case BPF_FUNC_this_cpu_ptr:
+		return &bpf_this_cpu_ptr_proto;
+	case BPF_FUNC_task_storage_get:
+		return &bpf_task_storage_get_proto;
+	case BPF_FUNC_task_storage_delete:
+		return &bpf_task_storage_delete_proto;
+	case BPF_FUNC_for_each_map_elem:
+		return &bpf_for_each_map_elem_proto;
+	case BPF_FUNC_snprintf:
+		return &bpf_snprintf_proto;
+	case BPF_FUNC_get_func_ip:
+		return &bpf_get_func_ip_proto_tracing;
+	case BPF_FUNC_get_branch_snapshot:
+		return &bpf_get_branch_snapshot_proto;
+	case BPF_FUNC_find_vma:
+		return &bpf_find_vma_proto;
+	case BPF_FUNC_trace_vprintk:
+		return bpf_get_trace_vprintk_proto();
+	default:
+		return bpf_base_func_proto(func_id);
+	}
+}
+
+static const struct bpf_func_proto *
+kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	switch (func_id) {
+	case BPF_FUNC_perf_event_output:
+		return &bpf_perf_event_output_proto;
+	case BPF_FUNC_get_stackid:
+		return &bpf_get_stackid_proto;
+	case BPF_FUNC_get_stack:
+		return &bpf_get_stack_proto;
+#ifdef CONFIG_BPF_KPROBE_OVERRIDE
+	case BPF_FUNC_override_return:
+		return &bpf_override_return_proto;
+#endif
+	case BPF_FUNC_get_func_ip:
+		return prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI ?
+			&bpf_get_func_ip_proto_kprobe_multi :
+			&bpf_get_func_ip_proto_kprobe;
+	case BPF_FUNC_get_attach_cookie:
+		return prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI ?
+			&bpf_get_attach_cookie_proto_kmulti :
+			&bpf_get_attach_cookie_proto_trace;
+	default:
+		return bpf_tracing_func_proto(func_id, prog);
+	}
+}
+
+/* bpf+kprobe programs can access fields of 'struct pt_regs' */
+static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
+					const struct bpf_prog *prog,
+					struct bpf_insn_access_aux *info)
+{
+	if (off < 0 || off >= sizeof(struct pt_regs))
+		return false;
+	if (type != BPF_READ)
+		return false;
+	if (off % size != 0)
+		return false;
+	/*
+	 * Assertion for 32 bit to make sure last 8 byte access
+	 * (BPF_DW) to the last 4 byte member is disallowed.
+	 */
+	if (off + size > sizeof(struct pt_regs))
+		return false;
+
+	return true;
+}
+
+const struct bpf_verifier_ops kprobe_verifier_ops = {
+	.get_func_proto  = kprobe_prog_func_proto,
+	.is_valid_access = kprobe_prog_is_valid_access,
+};
+
+const struct bpf_prog_ops kprobe_prog_ops = {
+};
+
+BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map,
+	   u64, flags, void *, data, u64, size)
+{
+	struct pt_regs *regs = *(struct pt_regs **)tp_buff;
+
+	/*
+	 * r1 points to perf tracepoint buffer where first 8 bytes are hidden
+	 * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it
+	 * from there and call the same bpf_perf_event_output() helper inline.
+	 */
+	return ____bpf_perf_event_output(regs, map, flags, data, size);
+}
+
+static const struct bpf_func_proto bpf_perf_event_output_proto_tp = {
+	.func		= bpf_perf_event_output_tp,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_CONST_MAP_PTR,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg5_type	= ARG_CONST_SIZE_OR_ZERO,
+};
+
+BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map,
+	   u64, flags)
+{
+	struct pt_regs *regs = *(struct pt_regs **)tp_buff;
+
+	/*
+	 * Same comment as in bpf_perf_event_output_tp(), only that this time
+	 * the other helper's function body cannot be inlined due to being
+	 * external, thus we need to call raw helper function.
+	 */
+	return bpf_get_stackid((unsigned long) regs, (unsigned long) map,
+			       flags, 0, 0);
+}
+
+static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
+	.func		= bpf_get_stackid_tp,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_CONST_MAP_PTR,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_4(bpf_get_stack_tp, void *, tp_buff, void *, buf, u32, size,
+	   u64, flags)
+{
+	struct pt_regs *regs = *(struct pt_regs **)tp_buff;
+
+	return bpf_get_stack((unsigned long) regs, (unsigned long) buf,
+			     (unsigned long) size, flags, 0);
+}
+
+static const struct bpf_func_proto bpf_get_stack_proto_tp = {
+	.func		= bpf_get_stack_tp,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,
+	.arg3_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+static const struct bpf_func_proto *
+tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	switch (func_id) {
+	case BPF_FUNC_perf_event_output:
+		return &bpf_perf_event_output_proto_tp;
+	case BPF_FUNC_get_stackid:
+		return &bpf_get_stackid_proto_tp;
+	case BPF_FUNC_get_stack:
+		return &bpf_get_stack_proto_tp;
+	case BPF_FUNC_get_attach_cookie:
+		return &bpf_get_attach_cookie_proto_trace;
+	default:
+		return bpf_tracing_func_proto(func_id, prog);
+	}
+}
+
+static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type,
+				    const struct bpf_prog *prog,
+				    struct bpf_insn_access_aux *info)
+{
+	if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE)
+		return false;
+	if (type != BPF_READ)
+		return false;
+	if (off % size != 0)
+		return false;
+
+	BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64));
+	return true;
+}
+
+const struct bpf_verifier_ops tracepoint_verifier_ops = {
+	.get_func_proto  = tp_prog_func_proto,
+	.is_valid_access = tp_prog_is_valid_access,
+};
+
+const struct bpf_prog_ops tracepoint_prog_ops = {
+};
+
+BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx,
+	   struct bpf_perf_event_value *, buf, u32, size)
+{
+	int err = -EINVAL;
+
+	if (unlikely(size != sizeof(struct bpf_perf_event_value)))
+		goto clear;
+	err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled,
+				    &buf->running);
+	if (unlikely(err))
+		goto clear;
+	return 0;
+clear:
+	memset(buf, 0, size);
+	return err;
+}
+
+static const struct bpf_func_proto bpf_perf_prog_read_value_proto = {
+         .func           = bpf_perf_prog_read_value,
+         .gpl_only       = true,
+         .ret_type       = RET_INTEGER,
+         .arg1_type      = ARG_PTR_TO_CTX,
+         .arg2_type      = ARG_PTR_TO_UNINIT_MEM,
+         .arg3_type      = ARG_CONST_SIZE,
+};
+
+BPF_CALL_4(bpf_read_branch_records, struct bpf_perf_event_data_kern *, ctx,
+	   void *, buf, u32, size, u64, flags)
+{
+	static const u32 br_entry_size = sizeof(struct perf_branch_entry);
+	struct perf_branch_stack *br_stack = ctx->data->br_stack;
+	u32 to_copy;
+
+	if (unlikely(flags & ~BPF_F_GET_BRANCH_RECORDS_SIZE))
+		return -EINVAL;
+
+	if (unlikely(!(ctx->data->sample_flags & PERF_SAMPLE_BRANCH_STACK)))
+		return -ENOENT;
+
+	if (unlikely(!br_stack))
+		return -ENOENT;
+
+	if (flags & BPF_F_GET_BRANCH_RECORDS_SIZE)
+		return br_stack->nr * br_entry_size;
+
+	if (!buf || (size % br_entry_size != 0))
+		return -EINVAL;
+
+	to_copy = min_t(u32, br_stack->nr * br_entry_size, size);
+	memcpy(buf, br_stack->entries, to_copy);
+
+	return to_copy;
+}
+
+static const struct bpf_func_proto bpf_read_branch_records_proto = {
+	.func           = bpf_read_branch_records,
+	.gpl_only       = true,
+	.ret_type       = RET_INTEGER,
+	.arg1_type      = ARG_PTR_TO_CTX,
+	.arg2_type      = ARG_PTR_TO_MEM_OR_NULL,
+	.arg3_type      = ARG_CONST_SIZE_OR_ZERO,
+	.arg4_type      = ARG_ANYTHING,
+};
+
+static const struct bpf_func_proto *
+pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	switch (func_id) {
+	case BPF_FUNC_perf_event_output:
+		return &bpf_perf_event_output_proto_tp;
+	case BPF_FUNC_get_stackid:
+		return &bpf_get_stackid_proto_pe;
+	case BPF_FUNC_get_stack:
+		return &bpf_get_stack_proto_pe;
+	case BPF_FUNC_perf_prog_read_value:
+		return &bpf_perf_prog_read_value_proto;
+	case BPF_FUNC_read_branch_records:
+		return &bpf_read_branch_records_proto;
+	case BPF_FUNC_get_attach_cookie:
+		return &bpf_get_attach_cookie_proto_pe;
+	default:
+		return bpf_tracing_func_proto(func_id, prog);
+	}
+}
+
+/*
+ * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp
+ * to avoid potential recursive reuse issue when/if tracepoints are added
+ * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack.
+ *
+ * Since raw tracepoints run despite bpf_prog_active, support concurrent usage
+ * in normal, irq, and nmi context.
+ */
+struct bpf_raw_tp_regs {
+	struct pt_regs regs[3];
+};
+static DEFINE_PER_CPU(struct bpf_raw_tp_regs, bpf_raw_tp_regs);
+static DEFINE_PER_CPU(int, bpf_raw_tp_nest_level);
+static struct pt_regs *get_bpf_raw_tp_regs(void)
+{
+	struct bpf_raw_tp_regs *tp_regs = this_cpu_ptr(&bpf_raw_tp_regs);
+	int nest_level = this_cpu_inc_return(bpf_raw_tp_nest_level);
+
+	if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(tp_regs->regs))) {
+		this_cpu_dec(bpf_raw_tp_nest_level);
+		return ERR_PTR(-EBUSY);
+	}
+
+	return &tp_regs->regs[nest_level - 1];
+}
+
+static void put_bpf_raw_tp_regs(void)
+{
+	this_cpu_dec(bpf_raw_tp_nest_level);
+}
+
+BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args,
+	   struct bpf_map *, map, u64, flags, void *, data, u64, size)
+{
+	struct pt_regs *regs = get_bpf_raw_tp_regs();
+	int ret;
+
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	perf_fetch_caller_regs(regs);
+	ret = ____bpf_perf_event_output(regs, map, flags, data, size);
+
+	put_bpf_raw_tp_regs();
+	return ret;
+}
+
+static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = {
+	.func		= bpf_perf_event_output_raw_tp,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_CONST_MAP_PTR,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg5_type	= ARG_CONST_SIZE_OR_ZERO,
+};
+
+extern const struct bpf_func_proto bpf_skb_output_proto;
+extern const struct bpf_func_proto bpf_xdp_output_proto;
+extern const struct bpf_func_proto bpf_xdp_get_buff_len_trace_proto;
+
+BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args,
+	   struct bpf_map *, map, u64, flags)
+{
+	struct pt_regs *regs = get_bpf_raw_tp_regs();
+	int ret;
+
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	perf_fetch_caller_regs(regs);
+	/* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */
+	ret = bpf_get_stackid((unsigned long) regs, (unsigned long) map,
+			      flags, 0, 0);
+	put_bpf_raw_tp_regs();
+	return ret;
+}
+
+static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = {
+	.func		= bpf_get_stackid_raw_tp,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_CONST_MAP_PTR,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args,
+	   void *, buf, u32, size, u64, flags)
+{
+	struct pt_regs *regs = get_bpf_raw_tp_regs();
+	int ret;
+
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	perf_fetch_caller_regs(regs);
+	ret = bpf_get_stack((unsigned long) regs, (unsigned long) buf,
+			    (unsigned long) size, flags, 0);
+	put_bpf_raw_tp_regs();
+	return ret;
+}
+
+static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = {
+	.func		= bpf_get_stack_raw_tp,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg3_type	= ARG_CONST_SIZE_OR_ZERO,
+	.arg4_type	= ARG_ANYTHING,
+};
+
+static const struct bpf_func_proto *
+raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	switch (func_id) {
+	case BPF_FUNC_perf_event_output:
+		return &bpf_perf_event_output_proto_raw_tp;
+	case BPF_FUNC_get_stackid:
+		return &bpf_get_stackid_proto_raw_tp;
+	case BPF_FUNC_get_stack:
+		return &bpf_get_stack_proto_raw_tp;
+	default:
+		return bpf_tracing_func_proto(func_id, prog);
+	}
+}
+
+const struct bpf_func_proto *
+tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	const struct bpf_func_proto *fn;
+
+	switch (func_id) {
+#ifdef CONFIG_NET
+	case BPF_FUNC_skb_output:
+		return &bpf_skb_output_proto;
+	case BPF_FUNC_xdp_output:
+		return &bpf_xdp_output_proto;
+	case BPF_FUNC_skc_to_tcp6_sock:
+		return &bpf_skc_to_tcp6_sock_proto;
+	case BPF_FUNC_skc_to_tcp_sock:
+		return &bpf_skc_to_tcp_sock_proto;
+	case BPF_FUNC_skc_to_tcp_timewait_sock:
+		return &bpf_skc_to_tcp_timewait_sock_proto;
+	case BPF_FUNC_skc_to_tcp_request_sock:
+		return &bpf_skc_to_tcp_request_sock_proto;
+	case BPF_FUNC_skc_to_udp6_sock:
+		return &bpf_skc_to_udp6_sock_proto;
+	case BPF_FUNC_skc_to_unix_sock:
+		return &bpf_skc_to_unix_sock_proto;
+	case BPF_FUNC_skc_to_mptcp_sock:
+		return &bpf_skc_to_mptcp_sock_proto;
+	case BPF_FUNC_sk_storage_get:
+		return &bpf_sk_storage_get_tracing_proto;
+	case BPF_FUNC_sk_storage_delete:
+		return &bpf_sk_storage_delete_tracing_proto;
+	case BPF_FUNC_sock_from_file:
+		return &bpf_sock_from_file_proto;
+	case BPF_FUNC_get_socket_cookie:
+		return &bpf_get_socket_ptr_cookie_proto;
+	case BPF_FUNC_xdp_get_buff_len:
+		return &bpf_xdp_get_buff_len_trace_proto;
+#endif
+	case BPF_FUNC_seq_printf:
+		return prog->expected_attach_type == BPF_TRACE_ITER ?
+		       &bpf_seq_printf_proto :
+		       NULL;
+	case BPF_FUNC_seq_write:
+		return prog->expected_attach_type == BPF_TRACE_ITER ?
+		       &bpf_seq_write_proto :
+		       NULL;
+	case BPF_FUNC_seq_printf_btf:
+		return prog->expected_attach_type == BPF_TRACE_ITER ?
+		       &bpf_seq_printf_btf_proto :
+		       NULL;
+	case BPF_FUNC_d_path:
+		return &bpf_d_path_proto;
+	case BPF_FUNC_get_func_arg:
+		return bpf_prog_has_trampoline(prog) ? &bpf_get_func_arg_proto : NULL;
+	case BPF_FUNC_get_func_ret:
+		return bpf_prog_has_trampoline(prog) ? &bpf_get_func_ret_proto : NULL;
+	case BPF_FUNC_get_func_arg_cnt:
+		return bpf_prog_has_trampoline(prog) ? &bpf_get_func_arg_cnt_proto : NULL;
+	case BPF_FUNC_get_attach_cookie:
+		return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto_tracing : NULL;
+	default:
+		fn = raw_tp_prog_func_proto(func_id, prog);
+		if (!fn && prog->expected_attach_type == BPF_TRACE_ITER)
+			fn = bpf_iter_get_func_proto(func_id, prog);
+		return fn;
+	}
+}
+
+static bool raw_tp_prog_is_valid_access(int off, int size,
+					enum bpf_access_type type,
+					const struct bpf_prog *prog,
+					struct bpf_insn_access_aux *info)
+{
+	return bpf_tracing_ctx_access(off, size, type);
+}
+
+static bool tracing_prog_is_valid_access(int off, int size,
+					 enum bpf_access_type type,
+					 const struct bpf_prog *prog,
+					 struct bpf_insn_access_aux *info)
+{
+	return bpf_tracing_btf_ctx_access(off, size, type, prog, info);
+}
+
+int __weak bpf_prog_test_run_tracing(struct bpf_prog *prog,
+				     const union bpf_attr *kattr,
+				     union bpf_attr __user *uattr)
+{
+	return -ENOTSUPP;
+}
+
+const struct bpf_verifier_ops raw_tracepoint_verifier_ops = {
+	.get_func_proto  = raw_tp_prog_func_proto,
+	.is_valid_access = raw_tp_prog_is_valid_access,
+};
+
+const struct bpf_prog_ops raw_tracepoint_prog_ops = {
+#ifdef CONFIG_NET
+	.test_run = bpf_prog_test_run_raw_tp,
+#endif
+};
+
+const struct bpf_verifier_ops tracing_verifier_ops = {
+	.get_func_proto  = tracing_prog_func_proto,
+	.is_valid_access = tracing_prog_is_valid_access,
+};
+
+const struct bpf_prog_ops tracing_prog_ops = {
+	.test_run = bpf_prog_test_run_tracing,
+};
+
+static bool raw_tp_writable_prog_is_valid_access(int off, int size,
+						 enum bpf_access_type type,
+						 const struct bpf_prog *prog,
+						 struct bpf_insn_access_aux *info)
+{
+	if (off == 0) {
+		if (size != sizeof(u64) || type != BPF_READ)
+			return false;
+		info->reg_type = PTR_TO_TP_BUFFER;
+	}
+	return raw_tp_prog_is_valid_access(off, size, type, prog, info);
+}
+
+const struct bpf_verifier_ops raw_tracepoint_writable_verifier_ops = {
+	.get_func_proto  = raw_tp_prog_func_proto,
+	.is_valid_access = raw_tp_writable_prog_is_valid_access,
+};
+
+const struct bpf_prog_ops raw_tracepoint_writable_prog_ops = {
+};
+
+static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
+				    const struct bpf_prog *prog,
+				    struct bpf_insn_access_aux *info)
+{
+	const int size_u64 = sizeof(u64);
+
+	if (off < 0 || off >= sizeof(struct bpf_perf_event_data))
+		return false;
+	if (type != BPF_READ)
+		return false;
+	if (off % size != 0) {
+		if (sizeof(unsigned long) != 4)
+			return false;
+		if (size != 8)
+			return false;
+		if (off % size != 4)
+			return false;
+	}
+
+	switch (off) {
+	case bpf_ctx_range(struct bpf_perf_event_data, sample_period):
+		bpf_ctx_record_field_size(info, size_u64);
+		if (!bpf_ctx_narrow_access_ok(off, size, size_u64))
+			return false;
+		break;
+	case bpf_ctx_range(struct bpf_perf_event_data, addr):
+		bpf_ctx_record_field_size(info, size_u64);
+		if (!bpf_ctx_narrow_access_ok(off, size, size_u64))
+			return false;
+		break;
+	default:
+		if (size != sizeof(long))
+			return false;
+	}
+
+	return true;
+}
+
+static u32 pe_prog_convert_ctx_access(enum bpf_access_type type,
+				      const struct bpf_insn *si,
+				      struct bpf_insn *insn_buf,
+				      struct bpf_prog *prog, u32 *target_size)
+{
+	struct bpf_insn *insn = insn_buf;
+
+	switch (si->off) {
+	case offsetof(struct bpf_perf_event_data, sample_period):
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
+						       data), si->dst_reg, si->src_reg,
+				      offsetof(struct bpf_perf_event_data_kern, data));
+		*insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
+				      bpf_target_off(struct perf_sample_data, period, 8,
+						     target_size));
+		break;
+	case offsetof(struct bpf_perf_event_data, addr):
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
+						       data), si->dst_reg, si->src_reg,
+				      offsetof(struct bpf_perf_event_data_kern, data));
+		*insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
+				      bpf_target_off(struct perf_sample_data, addr, 8,
+						     target_size));
+		break;
+	default:
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
+						       regs), si->dst_reg, si->src_reg,
+				      offsetof(struct bpf_perf_event_data_kern, regs));
+		*insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg,
+				      si->off);
+		break;
+	}
+
+	return insn - insn_buf;
+}
+
+const struct bpf_verifier_ops perf_event_verifier_ops = {
+	.get_func_proto		= pe_prog_func_proto,
+	.is_valid_access	= pe_prog_is_valid_access,
+	.convert_ctx_access	= pe_prog_convert_ctx_access,
+};
+
+const struct bpf_prog_ops perf_event_prog_ops = {
+};
+
+static DEFINE_MUTEX(bpf_event_mutex);
+
+#define BPF_TRACE_MAX_PROGS 64
+
+int perf_event_attach_bpf_prog(struct perf_event *event,
+			       struct bpf_prog *prog,
+			       u64 bpf_cookie)
+{
+	struct bpf_prog_array *old_array;
+	struct bpf_prog_array *new_array;
+	int ret = -EEXIST;
+
+	/*
+	 * Kprobe override only works if they are on the function entry,
+	 * and only if they are on the opt-in list.
+	 */
+	if (prog->kprobe_override &&
+	    (!trace_kprobe_on_func_entry(event->tp_event) ||
+	     !trace_kprobe_error_injectable(event->tp_event)))
+		return -EINVAL;
+
+	mutex_lock(&bpf_event_mutex);
+
+	if (event->prog)
+		goto unlock;
+
+	old_array = bpf_event_rcu_dereference(event->tp_event->prog_array);
+	if (old_array &&
+	    bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) {
+		ret = -E2BIG;
+		goto unlock;
+	}
+
+	ret = bpf_prog_array_copy(old_array, NULL, prog, bpf_cookie, &new_array);
+	if (ret < 0)
+		goto unlock;
+
+	/* set the new array to event->tp_event and set event->prog */
+	event->prog = prog;
+	event->bpf_cookie = bpf_cookie;
+	rcu_assign_pointer(event->tp_event->prog_array, new_array);
+	bpf_prog_array_free_sleepable(old_array);
+
+unlock:
+	mutex_unlock(&bpf_event_mutex);
+	return ret;
+}
+
+void perf_event_detach_bpf_prog(struct perf_event *event)
+{
+	struct bpf_prog_array *old_array;
+	struct bpf_prog_array *new_array;
+	int ret;
+
+	mutex_lock(&bpf_event_mutex);
+
+	if (!event->prog)
+		goto unlock;
+
+	old_array = bpf_event_rcu_dereference(event->tp_event->prog_array);
+	ret = bpf_prog_array_copy(old_array, event->prog, NULL, 0, &new_array);
+	if (ret == -ENOENT)
+		goto unlock;
+	if (ret < 0) {
+		bpf_prog_array_delete_safe(old_array, event->prog);
+	} else {
+		rcu_assign_pointer(event->tp_event->prog_array, new_array);
+		bpf_prog_array_free_sleepable(old_array);
+	}
+
+	bpf_prog_put(event->prog);
+	event->prog = NULL;
+
+unlock:
+	mutex_unlock(&bpf_event_mutex);
+}
+
+int perf_event_query_prog_array(struct perf_event *event, void __user *info)
+{
+	struct perf_event_query_bpf __user *uquery = info;
+	struct perf_event_query_bpf query = {};
+	struct bpf_prog_array *progs;
+	u32 *ids, prog_cnt, ids_len;
+	int ret;
+
+	if (!perfmon_capable())
+		return -EPERM;
+	if (event->attr.type != PERF_TYPE_TRACEPOINT)
+		return -EINVAL;
+	if (copy_from_user(&query, uquery, sizeof(query)))
+		return -EFAULT;
+
+	ids_len = query.ids_len;
+	if (ids_len > BPF_TRACE_MAX_PROGS)
+		return -E2BIG;
+	ids = kcalloc(ids_len, sizeof(u32), GFP_USER | __GFP_NOWARN);
+	if (!ids)
+		return -ENOMEM;
+	/*
+	 * The above kcalloc returns ZERO_SIZE_PTR when ids_len = 0, which
+	 * is required when user only wants to check for uquery->prog_cnt.
+	 * There is no need to check for it since the case is handled
+	 * gracefully in bpf_prog_array_copy_info.
+	 */
+
+	mutex_lock(&bpf_event_mutex);
+	progs = bpf_event_rcu_dereference(event->tp_event->prog_array);
+	ret = bpf_prog_array_copy_info(progs, ids, ids_len, &prog_cnt);
+	mutex_unlock(&bpf_event_mutex);
+
+	if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) ||
+	    copy_to_user(uquery->ids, ids, ids_len * sizeof(u32)))
+		ret = -EFAULT;
+
+	kfree(ids);
+	return ret;
+}
+
+extern struct bpf_raw_event_map __start__bpf_raw_tp[];
+extern struct bpf_raw_event_map __stop__bpf_raw_tp[];
+
+struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name)
+{
+	struct bpf_raw_event_map *btp = __start__bpf_raw_tp;
+
+	for (; btp < __stop__bpf_raw_tp; btp++) {
+		if (!strcmp(btp->tp->name, name))
+			return btp;
+	}
+
+	return bpf_get_raw_tracepoint_module(name);
+}
+
+void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp)
+{
+	struct module *mod;
+
+	preempt_disable();
+	mod = __module_address((unsigned long)btp);
+	module_put(mod);
+	preempt_enable();
+}
+
+static __always_inline
+void __bpf_trace_run(struct bpf_prog *prog, u64 *args)
+{
+	cant_sleep();
+	if (unlikely(this_cpu_inc_return(*(prog->active)) != 1)) {
+		bpf_prog_inc_misses_counter(prog);
+		goto out;
+	}
+	rcu_read_lock();
+	(void) bpf_prog_run(prog, args);
+	rcu_read_unlock();
+out:
+	this_cpu_dec(*(prog->active));
+}
+
+#define UNPACK(...)			__VA_ARGS__
+#define REPEAT_1(FN, DL, X, ...)	FN(X)
+#define REPEAT_2(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__)
+#define REPEAT_3(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__)
+#define REPEAT_4(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__)
+#define REPEAT_5(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__)
+#define REPEAT_6(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__)
+#define REPEAT_7(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__)
+#define REPEAT_8(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__)
+#define REPEAT_9(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__)
+#define REPEAT_10(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_9(FN, DL, __VA_ARGS__)
+#define REPEAT_11(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_10(FN, DL, __VA_ARGS__)
+#define REPEAT_12(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_11(FN, DL, __VA_ARGS__)
+#define REPEAT(X, FN, DL, ...)		REPEAT_##X(FN, DL, __VA_ARGS__)
+
+#define SARG(X)		u64 arg##X
+#define COPY(X)		args[X] = arg##X
+
+#define __DL_COM	(,)
+#define __DL_SEM	(;)
+
+#define __SEQ_0_11	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
+
+#define BPF_TRACE_DEFN_x(x)						\
+	void bpf_trace_run##x(struct bpf_prog *prog,			\
+			      REPEAT(x, SARG, __DL_COM, __SEQ_0_11))	\
+	{								\
+		u64 args[x];						\
+		REPEAT(x, COPY, __DL_SEM, __SEQ_0_11);			\
+		__bpf_trace_run(prog, args);				\
+	}								\
+	EXPORT_SYMBOL_GPL(bpf_trace_run##x)
+BPF_TRACE_DEFN_x(1);
+BPF_TRACE_DEFN_x(2);
+BPF_TRACE_DEFN_x(3);
+BPF_TRACE_DEFN_x(4);
+BPF_TRACE_DEFN_x(5);
+BPF_TRACE_DEFN_x(6);
+BPF_TRACE_DEFN_x(7);
+BPF_TRACE_DEFN_x(8);
+BPF_TRACE_DEFN_x(9);
+BPF_TRACE_DEFN_x(10);
+BPF_TRACE_DEFN_x(11);
+BPF_TRACE_DEFN_x(12);
+
+static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog)
+{
+	struct tracepoint *tp = btp->tp;
+
+	/*
+	 * check that program doesn't access arguments beyond what's
+	 * available in this tracepoint
+	 */
+	if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64))
+		return -EINVAL;
+
+	if (prog->aux->max_tp_access > btp->writable_size)
+		return -EINVAL;
+
+	return tracepoint_probe_register_may_exist(tp, (void *)btp->bpf_func,
+						   prog);
+}
+
+int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog)
+{
+	return __bpf_probe_register(btp, prog);
+}
+
+int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog)
+{
+	return tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog);
+}
+
+int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id,
+			    u32 *fd_type, const char **buf,
+			    u64 *probe_offset, u64 *probe_addr)
+{
+	bool is_tracepoint, is_syscall_tp;
+	struct bpf_prog *prog;
+	int flags, err = 0;
+
+	prog = event->prog;
+	if (!prog)
+		return -ENOENT;
+
+	/* not supporting BPF_PROG_TYPE_PERF_EVENT yet */
+	if (prog->type == BPF_PROG_TYPE_PERF_EVENT)
+		return -EOPNOTSUPP;
+
+	*prog_id = prog->aux->id;
+	flags = event->tp_event->flags;
+	is_tracepoint = flags & TRACE_EVENT_FL_TRACEPOINT;
+	is_syscall_tp = is_syscall_trace_event(event->tp_event);
+
+	if (is_tracepoint || is_syscall_tp) {
+		*buf = is_tracepoint ? event->tp_event->tp->name
+				     : event->tp_event->name;
+		*fd_type = BPF_FD_TYPE_TRACEPOINT;
+		*probe_offset = 0x0;
+		*probe_addr = 0x0;
+	} else {
+		/* kprobe/uprobe */
+		err = -EOPNOTSUPP;
+#ifdef CONFIG_KPROBE_EVENTS
+		if (flags & TRACE_EVENT_FL_KPROBE)
+			err = bpf_get_kprobe_info(event, fd_type, buf,
+						  probe_offset, probe_addr,
+						  event->attr.type == PERF_TYPE_TRACEPOINT);
+#endif
+#ifdef CONFIG_UPROBE_EVENTS
+		if (flags & TRACE_EVENT_FL_UPROBE)
+			err = bpf_get_uprobe_info(event, fd_type, buf,
+						  probe_offset, probe_addr,
+						  event->attr.type == PERF_TYPE_TRACEPOINT);
+#endif
+	}
+
+	return err;
+}
+
+static int __init send_signal_irq_work_init(void)
+{
+	int cpu;
+	struct send_signal_irq_work *work;
+
+	for_each_possible_cpu(cpu) {
+		work = per_cpu_ptr(&send_signal_work, cpu);
+		init_irq_work(&work->irq_work, do_bpf_send_signal);
+	}
+	return 0;
+}
+
+subsys_initcall(send_signal_irq_work_init);
+
+#ifdef CONFIG_MODULES
+static int bpf_event_notify(struct notifier_block *nb, unsigned long op,
+			    void *module)
+{
+	struct bpf_trace_module *btm, *tmp;
+	struct module *mod = module;
+	int ret = 0;
+
+	if (mod->num_bpf_raw_events == 0 ||
+	    (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING))
+		goto out;
+
+	mutex_lock(&bpf_module_mutex);
+
+	switch (op) {
+	case MODULE_STATE_COMING:
+		btm = kzalloc(sizeof(*btm), GFP_KERNEL);
+		if (btm) {
+			btm->module = module;
+			list_add(&btm->list, &bpf_trace_modules);
+		} else {
+			ret = -ENOMEM;
+		}
+		break;
+	case MODULE_STATE_GOING:
+		list_for_each_entry_safe(btm, tmp, &bpf_trace_modules, list) {
+			if (btm->module == module) {
+				list_del(&btm->list);
+				kfree(btm);
+				break;
+			}
+		}
+		break;
+	}
+
+	mutex_unlock(&bpf_module_mutex);
+
+out:
+	return notifier_from_errno(ret);
+}
+
+static struct notifier_block bpf_module_nb = {
+	.notifier_call = bpf_event_notify,
+};
+
+static int __init bpf_event_init(void)
+{
+	register_module_notifier(&bpf_module_nb);
+	return 0;
+}
+
+fs_initcall(bpf_event_init);
+#endif /* CONFIG_MODULES */
+
+#ifdef CONFIG_FPROBE
+struct bpf_kprobe_multi_link {
+	struct bpf_link link;
+	struct fprobe fp;
+	unsigned long *addrs;
+	u64 *cookies;
+	u32 cnt;
+};
+
+struct bpf_kprobe_multi_run_ctx {
+	struct bpf_run_ctx run_ctx;
+	struct bpf_kprobe_multi_link *link;
+	unsigned long entry_ip;
+};
+
+struct user_syms {
+	const char **syms;
+	char *buf;
+};
+
+static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32 cnt)
+{
+	unsigned long __user usymbol;
+	const char **syms = NULL;
+	char *buf = NULL, *p;
+	int err = -ENOMEM;
+	unsigned int i;
+
+	syms = kvmalloc_array(cnt, sizeof(*syms), GFP_KERNEL);
+	if (!syms)
+		goto error;
+
+	buf = kvmalloc_array(cnt, KSYM_NAME_LEN, GFP_KERNEL);
+	if (!buf)
+		goto error;
+
+	for (p = buf, i = 0; i < cnt; i++) {
+		if (__get_user(usymbol, usyms + i)) {
+			err = -EFAULT;
+			goto error;
+		}
+		err = strncpy_from_user(p, (const char __user *) usymbol, KSYM_NAME_LEN);
+		if (err == KSYM_NAME_LEN)
+			err = -E2BIG;
+		if (err < 0)
+			goto error;
+		syms[i] = p;
+		p += err + 1;
+	}
+
+	us->syms = syms;
+	us->buf = buf;
+	return 0;
+
+error:
+	if (err) {
+		kvfree(syms);
+		kvfree(buf);
+	}
+	return err;
+}
+
+static void free_user_syms(struct user_syms *us)
+{
+	kvfree(us->syms);
+	kvfree(us->buf);
+}
+
+static void bpf_kprobe_multi_link_release(struct bpf_link *link)
+{
+	struct bpf_kprobe_multi_link *kmulti_link;
+
+	kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link);
+	unregister_fprobe(&kmulti_link->fp);
+}
+
+static void bpf_kprobe_multi_link_dealloc(struct bpf_link *link)
+{
+	struct bpf_kprobe_multi_link *kmulti_link;
+
+	kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link);
+	kvfree(kmulti_link->addrs);
+	kvfree(kmulti_link->cookies);
+	kfree(kmulti_link);
+}
+
+static const struct bpf_link_ops bpf_kprobe_multi_link_lops = {
+	.release = bpf_kprobe_multi_link_release,
+	.dealloc = bpf_kprobe_multi_link_dealloc,
+};
+
+static void bpf_kprobe_multi_cookie_swap(void *a, void *b, int size, const void *priv)
+{
+	const struct bpf_kprobe_multi_link *link = priv;
+	unsigned long *addr_a = a, *addr_b = b;
+	u64 *cookie_a, *cookie_b;
+
+	cookie_a = link->cookies + (addr_a - link->addrs);
+	cookie_b = link->cookies + (addr_b - link->addrs);
+
+	/* swap addr_a/addr_b and cookie_a/cookie_b values */
+	swap(*addr_a, *addr_b);
+	swap(*cookie_a, *cookie_b);
+}
+
+static int __bpf_kprobe_multi_cookie_cmp(const void *a, const void *b)
+{
+	const unsigned long *addr_a = a, *addr_b = b;
+
+	if (*addr_a == *addr_b)
+		return 0;
+	return *addr_a < *addr_b ? -1 : 1;
+}
+
+static int bpf_kprobe_multi_cookie_cmp(const void *a, const void *b, const void *priv)
+{
+	return __bpf_kprobe_multi_cookie_cmp(a, b);
+}
+
+static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx)
+{
+	struct bpf_kprobe_multi_run_ctx *run_ctx;
+	struct bpf_kprobe_multi_link *link;
+	u64 *cookie, entry_ip;
+	unsigned long *addr;
+
+	if (WARN_ON_ONCE(!ctx))
+		return 0;
+	run_ctx = container_of(current->bpf_ctx, struct bpf_kprobe_multi_run_ctx, run_ctx);
+	link = run_ctx->link;
+	if (!link->cookies)
+		return 0;
+	entry_ip = run_ctx->entry_ip;
+	addr = bsearch(&entry_ip, link->addrs, link->cnt, sizeof(entry_ip),
+		       __bpf_kprobe_multi_cookie_cmp);
+	if (!addr)
+		return 0;
+	cookie = link->cookies + (addr - link->addrs);
+	return *cookie;
+}
+
+static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx)
+{
+	struct bpf_kprobe_multi_run_ctx *run_ctx;
+
+	run_ctx = container_of(current->bpf_ctx, struct bpf_kprobe_multi_run_ctx, run_ctx);
+	return run_ctx->entry_ip;
+}
+
+static int
+kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
+			   unsigned long entry_ip, struct pt_regs *regs)
+{
+	struct bpf_kprobe_multi_run_ctx run_ctx = {
+		.link = link,
+		.entry_ip = entry_ip,
+	};
+	struct bpf_run_ctx *old_run_ctx;
+	int err;
+
+	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
+		err = 0;
+		goto out;
+	}
+
+	migrate_disable();
+	rcu_read_lock();
+	old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
+	err = bpf_prog_run(link->link.prog, regs);
+	bpf_reset_run_ctx(old_run_ctx);
+	rcu_read_unlock();
+	migrate_enable();
+
+ out:
+	__this_cpu_dec(bpf_prog_active);
+	return err;
+}
+
+static void
+kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
+			  struct pt_regs *regs, void *data)
+{
+	struct bpf_kprobe_multi_link *link;
+
+	link = container_of(fp, struct bpf_kprobe_multi_link, fp);
+	kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
+}
+
+static int symbols_cmp_r(const void *a, const void *b, const void *priv)
+{
+	const char **str_a = (const char **) a;
+	const char **str_b = (const char **) b;
+
+	return strcmp(*str_a, *str_b);
+}
+
+struct multi_symbols_sort {
+	const char **funcs;
+	u64 *cookies;
+};
+
+static void symbols_swap_r(void *a, void *b, int size, const void *priv)
+{
+	const struct multi_symbols_sort *data = priv;
+	const char **name_a = a, **name_b = b;
+
+	swap(*name_a, *name_b);
+
+	/* If defined, swap also related cookies. */
+	if (data->cookies) {
+		u64 *cookie_a, *cookie_b;
+
+		cookie_a = data->cookies + (name_a - data->funcs);
+		cookie_b = data->cookies + (name_b - data->funcs);
+		swap(*cookie_a, *cookie_b);
+	}
+}
+
+static int addrs_check_error_injection_list(unsigned long *addrs, u32 cnt)
+{
+	u32 i;
+
+	for (i = 0; i < cnt; i++) {
+		if (!within_error_injection_list(addrs[i]))
+			return -EINVAL;
+	}
+	return 0;
+}
+
+int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
+{
+	struct bpf_kprobe_multi_link *link = NULL;
+	struct bpf_link_primer link_primer;
+	void __user *ucookies;
+	unsigned long *addrs;
+	u32 flags, cnt, size;
+	void __user *uaddrs;
+	u64 *cookies = NULL;
+	void __user *usyms;
+	int err;
+
+	/* no support for 32bit archs yet */
+	if (sizeof(u64) != sizeof(void *))
+		return -EOPNOTSUPP;
+
+	if (prog->expected_attach_type != BPF_TRACE_KPROBE_MULTI)
+		return -EINVAL;
+
+	flags = attr->link_create.kprobe_multi.flags;
+	if (flags & ~BPF_F_KPROBE_MULTI_RETURN)
+		return -EINVAL;
+
+	uaddrs = u64_to_user_ptr(attr->link_create.kprobe_multi.addrs);
+	usyms = u64_to_user_ptr(attr->link_create.kprobe_multi.syms);
+	if (!!uaddrs == !!usyms)
+		return -EINVAL;
+
+	cnt = attr->link_create.kprobe_multi.cnt;
+	if (!cnt)
+		return -EINVAL;
+
+	size = cnt * sizeof(*addrs);
+	addrs = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL);
+	if (!addrs)
+		return -ENOMEM;
+
+	ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies);
+	if (ucookies) {
+		cookies = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL);
+		if (!cookies) {
+			err = -ENOMEM;
+			goto error;
+		}
+		if (copy_from_user(cookies, ucookies, size)) {
+			err = -EFAULT;
+			goto error;
+		}
+	}
+
+	if (uaddrs) {
+		if (copy_from_user(addrs, uaddrs, size)) {
+			err = -EFAULT;
+			goto error;
+		}
+	} else {
+		struct multi_symbols_sort data = {
+			.cookies = cookies,
+		};
+		struct user_syms us;
+
+		err = copy_user_syms(&us, usyms, cnt);
+		if (err)
+			goto error;
+
+		if (cookies)
+			data.funcs = us.syms;
+
+		sort_r(us.syms, cnt, sizeof(*us.syms), symbols_cmp_r,
+		       symbols_swap_r, &data);
+
+		err = ftrace_lookup_symbols(us.syms, cnt, addrs);
+		free_user_syms(&us);
+		if (err)
+			goto error;
+	}
+
+	if (prog->kprobe_override && addrs_check_error_injection_list(addrs, cnt)) {
+		err = -EINVAL;
+		goto error;
+	}
+
+	link = kzalloc(sizeof(*link), GFP_KERNEL);
+	if (!link) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	bpf_link_init(&link->link, BPF_LINK_TYPE_KPROBE_MULTI,
+		      &bpf_kprobe_multi_link_lops, prog);
+
+	err = bpf_link_prime(&link->link, &link_primer);
+	if (err)
+		goto error;
+
+	if (flags & BPF_F_KPROBE_MULTI_RETURN)
+		link->fp.exit_handler = kprobe_multi_link_handler;
+	else
+		link->fp.entry_handler = kprobe_multi_link_handler;
+
+	link->addrs = addrs;
+	link->cookies = cookies;
+	link->cnt = cnt;
+
+	if (cookies) {
+		/*
+		 * Sorting addresses will trigger sorting cookies as well
+		 * (check bpf_kprobe_multi_cookie_swap). This way we can
+		 * find cookie based on the address in bpf_get_attach_cookie
+		 * helper.
+		 */
+		sort_r(addrs, cnt, sizeof(*addrs),
+		       bpf_kprobe_multi_cookie_cmp,
+		       bpf_kprobe_multi_cookie_swap,
+		       link);
+	}
+
+	err = register_fprobe_ips(&link->fp, addrs, cnt);
+	if (err) {
+		bpf_link_cleanup(&link_primer);
+		return err;
+	}
+
+	return bpf_link_settle(&link_primer);
+
+error:
+	kfree(link);
+	kvfree(addrs);
+	kvfree(cookies);
+	return err;
+}
+#else /* !CONFIG_FPROBE */
+int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
+{
+	return -EOPNOTSUPP;
+}
+static u64 bpf_kprobe_multi_cookie(struct bpf_run_ctx *ctx)
+{
+	return 0;
+}
+static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx)
+{
+	return 0;
+}
+#endif
diff --git a/kernel/trace/bpf_trace.h b/kernel/trace/bpf_trace.h
new file mode 100644
index 000000000..9acbc11ac
--- /dev/null
+++ b/kernel/trace/bpf_trace.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM bpf_trace
+
+#if !defined(_TRACE_BPF_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
+
+#define _TRACE_BPF_TRACE_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(bpf_trace_printk,
+
+	TP_PROTO(const char *bpf_string),
+
+	TP_ARGS(bpf_string),
+
+	TP_STRUCT__entry(
+		__string(bpf_string, bpf_string)
+	),
+
+	TP_fast_assign(
+		__assign_str(bpf_string, bpf_string);
+	),
+
+	TP_printk("%s", __get_str(bpf_string))
+);
+
+#endif /* _TRACE_BPF_TRACE_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE bpf_trace
+
+#include <trace/define_trace.h>
diff --git a/kernel/trace/error_report-traces.c b/kernel/trace/error_report-traces.c
new file mode 100644
index 000000000..f89792c25
--- /dev/null
+++ b/kernel/trace/error_report-traces.c
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Error reporting trace points.
+ *
+ * Copyright (C) 2021, Google LLC.
+ */
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/error_report.h>
+
+EXPORT_TRACEPOINT_SYMBOL_GPL(error_report_end);
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
new file mode 100644
index 000000000..218cd95bf
--- /dev/null
+++ b/kernel/trace/fgraph.c
@@ -0,0 +1,664 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Infrastructure to took into function calls and returns.
+ * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
+ * Mostly borrowed from function tracer which
+ * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
+ *
+ * Highly modified by Steven Rostedt (VMware).
+ */
+#include <linux/jump_label.h>
+#include <linux/suspend.h>
+#include <linux/ftrace.h>
+#include <linux/slab.h>
+
+#include <trace/events/sched.h>
+
+#include "ftrace_internal.h"
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+#define ASSIGN_OPS_HASH(opsname, val) \
+	.func_hash		= val, \
+	.local_hash.regex_lock	= __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
+#else
+#define ASSIGN_OPS_HASH(opsname, val)
+#endif
+
+DEFINE_STATIC_KEY_FALSE(kill_ftrace_graph);
+int ftrace_graph_active;
+
+/* Both enabled by default (can be cleared by function_graph tracer flags */
+static bool fgraph_sleep_time = true;
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+/*
+ * archs can override this function if they must do something
+ * to enable hook for graph tracer.
+ */
+int __weak ftrace_enable_ftrace_graph_caller(void)
+{
+	return 0;
+}
+
+/*
+ * archs can override this function if they must do something
+ * to disable hook for graph tracer.
+ */
+int __weak ftrace_disable_ftrace_graph_caller(void)
+{
+	return 0;
+}
+#endif
+
+/**
+ * ftrace_graph_stop - set to permanently disable function graph tracing
+ *
+ * In case of an error int function graph tracing, this is called
+ * to try to keep function graph tracing from causing any more harm.
+ * Usually this is pretty severe and this is called to try to at least
+ * get a warning out to the user.
+ */
+void ftrace_graph_stop(void)
+{
+	static_branch_enable(&kill_ftrace_graph);
+}
+
+/* Add a function return address to the trace stack on thread info.*/
+static int
+ftrace_push_return_trace(unsigned long ret, unsigned long func,
+			 unsigned long frame_pointer, unsigned long *retp)
+{
+	unsigned long long calltime;
+	int index;
+
+	if (unlikely(ftrace_graph_is_dead()))
+		return -EBUSY;
+
+	if (!current->ret_stack)
+		return -EBUSY;
+
+	/*
+	 * We must make sure the ret_stack is tested before we read
+	 * anything else.
+	 */
+	smp_rmb();
+
+	/* The return trace stack is full */
+	if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
+		atomic_inc(&current->trace_overrun);
+		return -EBUSY;
+	}
+
+	calltime = trace_clock_local();
+
+	index = ++current->curr_ret_stack;
+	barrier();
+	current->ret_stack[index].ret = ret;
+	current->ret_stack[index].func = func;
+	current->ret_stack[index].calltime = calltime;
+#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
+	current->ret_stack[index].fp = frame_pointer;
+#endif
+#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
+	current->ret_stack[index].retp = retp;
+#endif
+	return 0;
+}
+
+/*
+ * Not all archs define MCOUNT_INSN_SIZE which is used to look for direct
+ * functions. But those archs currently don't support direct functions
+ * anyway, and ftrace_find_rec_direct() is just a stub for them.
+ * Define MCOUNT_INSN_SIZE to keep those archs compiling.
+ */
+#ifndef MCOUNT_INSN_SIZE
+/* Make sure this only works without direct calls */
+# ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+#  error MCOUNT_INSN_SIZE not defined with direct calls enabled
+# endif
+# define MCOUNT_INSN_SIZE 0
+#endif
+
+int function_graph_enter(unsigned long ret, unsigned long func,
+			 unsigned long frame_pointer, unsigned long *retp)
+{
+	struct ftrace_graph_ent trace;
+
+#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
+	/*
+	 * Skip graph tracing if the return location is served by direct trampoline,
+	 * since call sequence and return addresses are unpredictable anyway.
+	 * Ex: BPF trampoline may call original function and may skip frame
+	 * depending on type of BPF programs attached.
+	 */
+	if (ftrace_direct_func_count &&
+	    ftrace_find_rec_direct(ret - MCOUNT_INSN_SIZE))
+		return -EBUSY;
+#endif
+	trace.func = func;
+	trace.depth = ++current->curr_ret_depth;
+
+	if (ftrace_push_return_trace(ret, func, frame_pointer, retp))
+		goto out;
+
+	/* Only trace if the calling function expects to */
+	if (!ftrace_graph_entry(&trace))
+		goto out_ret;
+
+	return 0;
+ out_ret:
+	current->curr_ret_stack--;
+ out:
+	current->curr_ret_depth--;
+	return -EBUSY;
+}
+
+/* Retrieve a function return address to the trace stack on thread info.*/
+static void
+ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
+			unsigned long frame_pointer)
+{
+	int index;
+
+	index = current->curr_ret_stack;
+
+	if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
+		ftrace_graph_stop();
+		WARN_ON(1);
+		/* Might as well panic, otherwise we have no where to go */
+		*ret = (unsigned long)panic;
+		return;
+	}
+
+#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
+	/*
+	 * The arch may choose to record the frame pointer used
+	 * and check it here to make sure that it is what we expect it
+	 * to be. If gcc does not set the place holder of the return
+	 * address in the frame pointer, and does a copy instead, then
+	 * the function graph trace will fail. This test detects this
+	 * case.
+	 *
+	 * Currently, x86_32 with optimize for size (-Os) makes the latest
+	 * gcc do the above.
+	 *
+	 * Note, -mfentry does not use frame pointers, and this test
+	 *  is not needed if CC_USING_FENTRY is set.
+	 */
+	if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
+		ftrace_graph_stop();
+		WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
+		     "  from func %ps return to %lx\n",
+		     current->ret_stack[index].fp,
+		     frame_pointer,
+		     (void *)current->ret_stack[index].func,
+		     current->ret_stack[index].ret);
+		*ret = (unsigned long)panic;
+		return;
+	}
+#endif
+
+	*ret = current->ret_stack[index].ret;
+	trace->func = current->ret_stack[index].func;
+	trace->calltime = current->ret_stack[index].calltime;
+	trace->overrun = atomic_read(&current->trace_overrun);
+	trace->depth = current->curr_ret_depth--;
+	/*
+	 * We still want to trace interrupts coming in if
+	 * max_depth is set to 1. Make sure the decrement is
+	 * seen before ftrace_graph_return.
+	 */
+	barrier();
+}
+
+/*
+ * Hibernation protection.
+ * The state of the current task is too much unstable during
+ * suspend/restore to disk. We want to protect against that.
+ */
+static int
+ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
+							void *unused)
+{
+	switch (state) {
+	case PM_HIBERNATION_PREPARE:
+		pause_graph_tracing();
+		break;
+
+	case PM_POST_HIBERNATION:
+		unpause_graph_tracing();
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block ftrace_suspend_notifier = {
+	.notifier_call = ftrace_suspend_notifier_call,
+};
+
+/*
+ * Send the trace to the ring-buffer.
+ * @return the original return address.
+ */
+unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
+{
+	struct ftrace_graph_ret trace;
+	unsigned long ret;
+
+	ftrace_pop_return_trace(&trace, &ret, frame_pointer);
+	trace.rettime = trace_clock_local();
+	ftrace_graph_return(&trace);
+	/*
+	 * The ftrace_graph_return() may still access the current
+	 * ret_stack structure, we need to make sure the update of
+	 * curr_ret_stack is after that.
+	 */
+	barrier();
+	current->curr_ret_stack--;
+
+	if (unlikely(!ret)) {
+		ftrace_graph_stop();
+		WARN_ON(1);
+		/* Might as well panic. What else to do? */
+		ret = (unsigned long)panic;
+	}
+
+	return ret;
+}
+
+/**
+ * ftrace_graph_get_ret_stack - return the entry of the shadow stack
+ * @task: The task to read the shadow stack from
+ * @idx: Index down the shadow stack
+ *
+ * Return the ret_struct on the shadow stack of the @task at the
+ * call graph at @idx starting with zero. If @idx is zero, it
+ * will return the last saved ret_stack entry. If it is greater than
+ * zero, it will return the corresponding ret_stack for the depth
+ * of saved return addresses.
+ */
+struct ftrace_ret_stack *
+ftrace_graph_get_ret_stack(struct task_struct *task, int idx)
+{
+	idx = task->curr_ret_stack - idx;
+
+	if (idx >= 0 && idx <= task->curr_ret_stack)
+		return &task->ret_stack[idx];
+
+	return NULL;
+}
+
+/**
+ * ftrace_graph_ret_addr - convert a potentially modified stack return address
+ *			   to its original value
+ *
+ * This function can be called by stack unwinding code to convert a found stack
+ * return address ('ret') to its original value, in case the function graph
+ * tracer has modified it to be 'return_to_handler'.  If the address hasn't
+ * been modified, the unchanged value of 'ret' is returned.
+ *
+ * 'idx' is a state variable which should be initialized by the caller to zero
+ * before the first call.
+ *
+ * 'retp' is a pointer to the return address on the stack.  It's ignored if
+ * the arch doesn't have HAVE_FUNCTION_GRAPH_RET_ADDR_PTR defined.
+ */
+#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
+unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
+				    unsigned long ret, unsigned long *retp)
+{
+	int index = task->curr_ret_stack;
+	int i;
+
+	if (ret != (unsigned long)dereference_kernel_function_descriptor(return_to_handler))
+		return ret;
+
+	if (index < 0)
+		return ret;
+
+	for (i = 0; i <= index; i++)
+		if (task->ret_stack[i].retp == retp)
+			return task->ret_stack[i].ret;
+
+	return ret;
+}
+#else /* !HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
+unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
+				    unsigned long ret, unsigned long *retp)
+{
+	int task_idx;
+
+	if (ret != (unsigned long)dereference_kernel_function_descriptor(return_to_handler))
+		return ret;
+
+	task_idx = task->curr_ret_stack;
+
+	if (!task->ret_stack || task_idx < *idx)
+		return ret;
+
+	task_idx -= *idx;
+	(*idx)++;
+
+	return task->ret_stack[task_idx].ret;
+}
+#endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
+
+static struct ftrace_ops graph_ops = {
+	.func			= ftrace_graph_func,
+	.flags			= FTRACE_OPS_FL_INITIALIZED |
+				   FTRACE_OPS_FL_PID |
+				   FTRACE_OPS_GRAPH_STUB,
+#ifdef FTRACE_GRAPH_TRAMP_ADDR
+	.trampoline		= FTRACE_GRAPH_TRAMP_ADDR,
+	/* trampoline_size is only needed for dynamically allocated tramps */
+#endif
+	ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
+};
+
+void ftrace_graph_sleep_time_control(bool enable)
+{
+	fgraph_sleep_time = enable;
+}
+
+int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
+{
+	return 0;
+}
+
+/*
+ * Simply points to ftrace_stub, but with the proper protocol.
+ * Defined by the linker script in linux/vmlinux.lds.h
+ */
+extern void ftrace_stub_graph(struct ftrace_graph_ret *);
+
+/* The callbacks that hook a function */
+trace_func_graph_ret_t ftrace_graph_return = ftrace_stub_graph;
+trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
+static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
+
+/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
+static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
+{
+	int i;
+	int ret = 0;
+	int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
+	struct task_struct *g, *t;
+
+	for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
+		ret_stack_list[i] =
+			kmalloc_array(FTRACE_RETFUNC_DEPTH,
+				      sizeof(struct ftrace_ret_stack),
+				      GFP_KERNEL);
+		if (!ret_stack_list[i]) {
+			start = 0;
+			end = i;
+			ret = -ENOMEM;
+			goto free;
+		}
+	}
+
+	rcu_read_lock();
+	for_each_process_thread(g, t) {
+		if (start == end) {
+			ret = -EAGAIN;
+			goto unlock;
+		}
+
+		if (t->ret_stack == NULL) {
+			atomic_set(&t->trace_overrun, 0);
+			t->curr_ret_stack = -1;
+			t->curr_ret_depth = -1;
+			/* Make sure the tasks see the -1 first: */
+			smp_wmb();
+			t->ret_stack = ret_stack_list[start++];
+		}
+	}
+
+unlock:
+	rcu_read_unlock();
+free:
+	for (i = start; i < end; i++)
+		kfree(ret_stack_list[i]);
+	return ret;
+}
+
+static void
+ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
+				struct task_struct *prev,
+				struct task_struct *next,
+				unsigned int prev_state)
+{
+	unsigned long long timestamp;
+	int index;
+
+	/*
+	 * Does the user want to count the time a function was asleep.
+	 * If so, do not update the time stamps.
+	 */
+	if (fgraph_sleep_time)
+		return;
+
+	timestamp = trace_clock_local();
+
+	prev->ftrace_timestamp = timestamp;
+
+	/* only process tasks that we timestamped */
+	if (!next->ftrace_timestamp)
+		return;
+
+	/*
+	 * Update all the counters in next to make up for the
+	 * time next was sleeping.
+	 */
+	timestamp -= next->ftrace_timestamp;
+
+	for (index = next->curr_ret_stack; index >= 0; index--)
+		next->ret_stack[index].calltime += timestamp;
+}
+
+static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
+{
+	if (!ftrace_ops_test(&global_ops, trace->func, NULL))
+		return 0;
+	return __ftrace_graph_entry(trace);
+}
+
+/*
+ * The function graph tracer should only trace the functions defined
+ * by set_ftrace_filter and set_ftrace_notrace. If another function
+ * tracer ops is registered, the graph tracer requires testing the
+ * function against the global ops, and not just trace any function
+ * that any ftrace_ops registered.
+ */
+void update_function_graph_func(void)
+{
+	struct ftrace_ops *op;
+	bool do_test = false;
+
+	/*
+	 * The graph and global ops share the same set of functions
+	 * to test. If any other ops is on the list, then
+	 * the graph tracing needs to test if its the function
+	 * it should call.
+	 */
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		if (op != &global_ops && op != &graph_ops &&
+		    op != &ftrace_list_end) {
+			do_test = true;
+			/* in double loop, break out with goto */
+			goto out;
+		}
+	} while_for_each_ftrace_op(op);
+ out:
+	if (do_test)
+		ftrace_graph_entry = ftrace_graph_entry_test;
+	else
+		ftrace_graph_entry = __ftrace_graph_entry;
+}
+
+static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
+
+static void
+graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
+{
+	atomic_set(&t->trace_overrun, 0);
+	t->ftrace_timestamp = 0;
+	/* make curr_ret_stack visible before we add the ret_stack */
+	smp_wmb();
+	t->ret_stack = ret_stack;
+}
+
+/*
+ * Allocate a return stack for the idle task. May be the first
+ * time through, or it may be done by CPU hotplug online.
+ */
+void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
+{
+	t->curr_ret_stack = -1;
+	t->curr_ret_depth = -1;
+	/*
+	 * The idle task has no parent, it either has its own
+	 * stack or no stack at all.
+	 */
+	if (t->ret_stack)
+		WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
+
+	if (ftrace_graph_active) {
+		struct ftrace_ret_stack *ret_stack;
+
+		ret_stack = per_cpu(idle_ret_stack, cpu);
+		if (!ret_stack) {
+			ret_stack =
+				kmalloc_array(FTRACE_RETFUNC_DEPTH,
+					      sizeof(struct ftrace_ret_stack),
+					      GFP_KERNEL);
+			if (!ret_stack)
+				return;
+			per_cpu(idle_ret_stack, cpu) = ret_stack;
+		}
+		graph_init_task(t, ret_stack);
+	}
+}
+
+/* Allocate a return stack for newly created task */
+void ftrace_graph_init_task(struct task_struct *t)
+{
+	/* Make sure we do not use the parent ret_stack */
+	t->ret_stack = NULL;
+	t->curr_ret_stack = -1;
+	t->curr_ret_depth = -1;
+
+	if (ftrace_graph_active) {
+		struct ftrace_ret_stack *ret_stack;
+
+		ret_stack = kmalloc_array(FTRACE_RETFUNC_DEPTH,
+					  sizeof(struct ftrace_ret_stack),
+					  GFP_KERNEL);
+		if (!ret_stack)
+			return;
+		graph_init_task(t, ret_stack);
+	}
+}
+
+void ftrace_graph_exit_task(struct task_struct *t)
+{
+	struct ftrace_ret_stack	*ret_stack = t->ret_stack;
+
+	t->ret_stack = NULL;
+	/* NULL must become visible to IRQs before we free it: */
+	barrier();
+
+	kfree(ret_stack);
+}
+
+/* Allocate a return stack for each task */
+static int start_graph_tracing(void)
+{
+	struct ftrace_ret_stack **ret_stack_list;
+	int ret, cpu;
+
+	ret_stack_list = kmalloc_array(FTRACE_RETSTACK_ALLOC_SIZE,
+				       sizeof(struct ftrace_ret_stack *),
+				       GFP_KERNEL);
+
+	if (!ret_stack_list)
+		return -ENOMEM;
+
+	/* The cpu_boot init_task->ret_stack will never be freed */
+	for_each_online_cpu(cpu) {
+		if (!idle_task(cpu)->ret_stack)
+			ftrace_graph_init_idle_task(idle_task(cpu), cpu);
+	}
+
+	do {
+		ret = alloc_retstack_tasklist(ret_stack_list);
+	} while (ret == -EAGAIN);
+
+	if (!ret) {
+		ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
+		if (ret)
+			pr_info("ftrace_graph: Couldn't activate tracepoint"
+				" probe to kernel_sched_switch\n");
+	}
+
+	kfree(ret_stack_list);
+	return ret;
+}
+
+int register_ftrace_graph(struct fgraph_ops *gops)
+{
+	int ret = 0;
+
+	mutex_lock(&ftrace_lock);
+
+	/* we currently allow only one tracer registered at a time */
+	if (ftrace_graph_active) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	register_pm_notifier(&ftrace_suspend_notifier);
+
+	ftrace_graph_active++;
+	ret = start_graph_tracing();
+	if (ret) {
+		ftrace_graph_active--;
+		goto out;
+	}
+
+	ftrace_graph_return = gops->retfunc;
+
+	/*
+	 * Update the indirect function to the entryfunc, and the
+	 * function that gets called to the entry_test first. Then
+	 * call the update fgraph entry function to determine if
+	 * the entryfunc should be called directly or not.
+	 */
+	__ftrace_graph_entry = gops->entryfunc;
+	ftrace_graph_entry = ftrace_graph_entry_test;
+	update_function_graph_func();
+
+	ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
+out:
+	mutex_unlock(&ftrace_lock);
+	return ret;
+}
+
+void unregister_ftrace_graph(struct fgraph_ops *gops)
+{
+	mutex_lock(&ftrace_lock);
+
+	if (unlikely(!ftrace_graph_active))
+		goto out;
+
+	ftrace_graph_active--;
+	ftrace_graph_return = ftrace_stub_graph;
+	ftrace_graph_entry = ftrace_graph_entry_stub;
+	__ftrace_graph_entry = ftrace_graph_entry_stub;
+	ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
+	unregister_pm_notifier(&ftrace_suspend_notifier);
+	unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
+
+ out:
+	mutex_unlock(&ftrace_lock);
+}
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
new file mode 100644
index 000000000..f386d6bd8
--- /dev/null
+++ b/kernel/trace/fprobe.c
@@ -0,0 +1,334 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fprobe - Simple ftrace probe wrapper for function entry.
+ */
+#define pr_fmt(fmt) "fprobe: " fmt
+
+#include <linux/err.h>
+#include <linux/fprobe.h>
+#include <linux/kallsyms.h>
+#include <linux/kprobes.h>
+#include <linux/rethook.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+
+#include "trace.h"
+
+struct fprobe_rethook_node {
+	struct rethook_node node;
+	unsigned long entry_ip;
+	char data[];
+};
+
+static void fprobe_handler(unsigned long ip, unsigned long parent_ip,
+			   struct ftrace_ops *ops, struct ftrace_regs *fregs)
+{
+	struct fprobe_rethook_node *fpr;
+	struct rethook_node *rh = NULL;
+	struct fprobe *fp;
+	void *entry_data = NULL;
+	int bit;
+
+	fp = container_of(ops, struct fprobe, ops);
+	if (fprobe_disabled(fp))
+		return;
+
+	bit = ftrace_test_recursion_trylock(ip, parent_ip);
+	if (bit < 0) {
+		fp->nmissed++;
+		return;
+	}
+
+	if (fp->exit_handler) {
+		rh = rethook_try_get(fp->rethook);
+		if (!rh) {
+			fp->nmissed++;
+			goto out;
+		}
+		fpr = container_of(rh, struct fprobe_rethook_node, node);
+		fpr->entry_ip = ip;
+		if (fp->entry_data_size)
+			entry_data = fpr->data;
+	}
+
+	if (fp->entry_handler)
+		fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data);
+
+	if (rh)
+		rethook_hook(rh, ftrace_get_regs(fregs), true);
+
+out:
+	ftrace_test_recursion_unlock(bit);
+}
+NOKPROBE_SYMBOL(fprobe_handler);
+
+static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip,
+				  struct ftrace_ops *ops, struct ftrace_regs *fregs)
+{
+	struct fprobe *fp = container_of(ops, struct fprobe, ops);
+
+	if (unlikely(kprobe_running())) {
+		fp->nmissed++;
+		return;
+	}
+	kprobe_busy_begin();
+	fprobe_handler(ip, parent_ip, ops, fregs);
+	kprobe_busy_end();
+}
+
+static void fprobe_exit_handler(struct rethook_node *rh, void *data,
+				struct pt_regs *regs)
+{
+	struct fprobe *fp = (struct fprobe *)data;
+	struct fprobe_rethook_node *fpr;
+
+	if (!fp || fprobe_disabled(fp))
+		return;
+
+	fpr = container_of(rh, struct fprobe_rethook_node, node);
+
+	fp->exit_handler(fp, fpr->entry_ip, regs,
+			 fp->entry_data_size ? (void *)fpr->data : NULL);
+}
+NOKPROBE_SYMBOL(fprobe_exit_handler);
+
+static int symbols_cmp(const void *a, const void *b)
+{
+	const char **str_a = (const char **) a;
+	const char **str_b = (const char **) b;
+
+	return strcmp(*str_a, *str_b);
+}
+
+/* Convert ftrace location address from symbols */
+static unsigned long *get_ftrace_locations(const char **syms, int num)
+{
+	unsigned long *addrs;
+
+	/* Convert symbols to symbol address */
+	addrs = kcalloc(num, sizeof(*addrs), GFP_KERNEL);
+	if (!addrs)
+		return ERR_PTR(-ENOMEM);
+
+	/* ftrace_lookup_symbols expects sorted symbols */
+	sort(syms, num, sizeof(*syms), symbols_cmp, NULL);
+
+	if (!ftrace_lookup_symbols(syms, num, addrs))
+		return addrs;
+
+	kfree(addrs);
+	return ERR_PTR(-ENOENT);
+}
+
+static void fprobe_init(struct fprobe *fp)
+{
+	fp->nmissed = 0;
+	if (fprobe_shared_with_kprobes(fp))
+		fp->ops.func = fprobe_kprobe_handler;
+	else
+		fp->ops.func = fprobe_handler;
+	fp->ops.flags |= FTRACE_OPS_FL_SAVE_REGS;
+}
+
+static int fprobe_init_rethook(struct fprobe *fp, int num)
+{
+	int i, size;
+
+	if (num <= 0)
+		return -EINVAL;
+
+	if (!fp->exit_handler) {
+		fp->rethook = NULL;
+		return 0;
+	}
+
+	/* Initialize rethook if needed */
+	if (fp->nr_maxactive)
+		size = fp->nr_maxactive;
+	else
+		size = num * num_possible_cpus() * 2;
+	if (size <= 0)
+		return -EINVAL;
+
+	fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler);
+	if (!fp->rethook)
+		return -ENOMEM;
+	for (i = 0; i < size; i++) {
+		struct fprobe_rethook_node *node;
+
+		node = kzalloc(sizeof(*node) + fp->entry_data_size, GFP_KERNEL);
+		if (!node) {
+			rethook_free(fp->rethook);
+			fp->rethook = NULL;
+			return -ENOMEM;
+		}
+		rethook_add_node(fp->rethook, &node->node);
+	}
+	return 0;
+}
+
+static void fprobe_fail_cleanup(struct fprobe *fp)
+{
+	if (fp->rethook) {
+		/* Don't need to cleanup rethook->handler because this is not used. */
+		rethook_free(fp->rethook);
+		fp->rethook = NULL;
+	}
+	ftrace_free_filter(&fp->ops);
+}
+
+/**
+ * register_fprobe() - Register fprobe to ftrace by pattern.
+ * @fp: A fprobe data structure to be registered.
+ * @filter: A wildcard pattern of probed symbols.
+ * @notfilter: A wildcard pattern of NOT probed symbols.
+ *
+ * Register @fp to ftrace for enabling the probe on the symbols matched to @filter.
+ * If @notfilter is not NULL, the symbols matched the @notfilter are not probed.
+ *
+ * Return 0 if @fp is registered successfully, -errno if not.
+ */
+int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter)
+{
+	struct ftrace_hash *hash;
+	unsigned char *str;
+	int ret, len;
+
+	if (!fp || !filter)
+		return -EINVAL;
+
+	fprobe_init(fp);
+
+	len = strlen(filter);
+	str = kstrdup(filter, GFP_KERNEL);
+	ret = ftrace_set_filter(&fp->ops, str, len, 0);
+	kfree(str);
+	if (ret)
+		return ret;
+
+	if (notfilter) {
+		len = strlen(notfilter);
+		str = kstrdup(notfilter, GFP_KERNEL);
+		ret = ftrace_set_notrace(&fp->ops, str, len, 0);
+		kfree(str);
+		if (ret)
+			goto out;
+	}
+
+	/* TODO:
+	 * correctly calculate the total number of filtered symbols
+	 * from both filter and notfilter.
+	 */
+	hash = rcu_access_pointer(fp->ops.local_hash.filter_hash);
+	if (WARN_ON_ONCE(!hash))
+		goto out;
+
+	ret = fprobe_init_rethook(fp, (int)hash->count);
+	if (!ret)
+		ret = register_ftrace_function(&fp->ops);
+
+out:
+	if (ret)
+		fprobe_fail_cleanup(fp);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_fprobe);
+
+/**
+ * register_fprobe_ips() - Register fprobe to ftrace by address.
+ * @fp: A fprobe data structure to be registered.
+ * @addrs: An array of target ftrace location addresses.
+ * @num: The number of entries of @addrs.
+ *
+ * Register @fp to ftrace for enabling the probe on the address given by @addrs.
+ * The @addrs must be the addresses of ftrace location address, which may be
+ * the symbol address + arch-dependent offset.
+ * If you unsure what this mean, please use other registration functions.
+ *
+ * Return 0 if @fp is registered successfully, -errno if not.
+ */
+int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num)
+{
+	int ret;
+
+	if (!fp || !addrs || num <= 0)
+		return -EINVAL;
+
+	fprobe_init(fp);
+
+	ret = ftrace_set_filter_ips(&fp->ops, addrs, num, 0, 0);
+	if (ret)
+		return ret;
+
+	ret = fprobe_init_rethook(fp, num);
+	if (!ret)
+		ret = register_ftrace_function(&fp->ops);
+
+	if (ret)
+		fprobe_fail_cleanup(fp);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_fprobe_ips);
+
+/**
+ * register_fprobe_syms() - Register fprobe to ftrace by symbols.
+ * @fp: A fprobe data structure to be registered.
+ * @syms: An array of target symbols.
+ * @num: The number of entries of @syms.
+ *
+ * Register @fp to the symbols given by @syms array. This will be useful if
+ * you are sure the symbols exist in the kernel.
+ *
+ * Return 0 if @fp is registered successfully, -errno if not.
+ */
+int register_fprobe_syms(struct fprobe *fp, const char **syms, int num)
+{
+	unsigned long *addrs;
+	int ret;
+
+	if (!fp || !syms || num <= 0)
+		return -EINVAL;
+
+	addrs = get_ftrace_locations(syms, num);
+	if (IS_ERR(addrs))
+		return PTR_ERR(addrs);
+
+	ret = register_fprobe_ips(fp, addrs, num);
+
+	kfree(addrs);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_fprobe_syms);
+
+/**
+ * unregister_fprobe() - Unregister fprobe from ftrace
+ * @fp: A fprobe data structure to be unregistered.
+ *
+ * Unregister fprobe (and remove ftrace hooks from the function entries).
+ *
+ * Return 0 if @fp is unregistered successfully, -errno if not.
+ */
+int unregister_fprobe(struct fprobe *fp)
+{
+	int ret;
+
+	if (!fp || (fp->ops.saved_func != fprobe_handler &&
+		    fp->ops.saved_func != fprobe_kprobe_handler))
+		return -EINVAL;
+
+	if (fp->rethook)
+		rethook_stop(fp->rethook);
+
+	ret = unregister_ftrace_function(&fp->ops);
+	if (ret < 0)
+		return ret;
+
+	if (fp->rethook)
+		rethook_free(fp->rethook);
+
+	ftrace_free_filter(&fp->ops);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(unregister_fprobe);
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
new file mode 100644
index 000000000..552956ccb
--- /dev/null
+++ b/kernel/trace/ftrace.c
@@ -0,0 +1,8472 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Infrastructure for profiling code inserted by 'gcc -pg'.
+ *
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
+ *
+ * Originally ported from the -rt patch by:
+ *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
+ *
+ * Based on code in the latency_tracer, that is:
+ *
+ *  Copyright (C) 2004-2006 Ingo Molnar
+ *  Copyright (C) 2004 Nadia Yvette Chambers
+ */
+
+#include <linux/stop_machine.h>
+#include <linux/clocksource.h>
+#include <linux/sched/task.h>
+#include <linux/kallsyms.h>
+#include <linux/security.h>
+#include <linux/seq_file.h>
+#include <linux/tracefs.h>
+#include <linux/hardirq.h>
+#include <linux/kthread.h>
+#include <linux/uaccess.h>
+#include <linux/bsearch.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+#include <linux/sysctl.h>
+#include <linux/slab.h>
+#include <linux/ctype.h>
+#include <linux/sort.h>
+#include <linux/list.h>
+#include <linux/hash.h>
+#include <linux/rcupdate.h>
+#include <linux/kprobes.h>
+
+#include <trace/events/sched.h>
+
+#include <asm/sections.h>
+#include <asm/setup.h>
+
+#include "ftrace_internal.h"
+#include "trace_output.h"
+#include "trace_stat.h"
+
+#define FTRACE_INVALID_FUNCTION		"__ftrace_invalid_address__"
+
+#define FTRACE_WARN_ON(cond)			\
+	({					\
+		int ___r = cond;		\
+		if (WARN_ON(___r))		\
+			ftrace_kill();		\
+		___r;				\
+	})
+
+#define FTRACE_WARN_ON_ONCE(cond)		\
+	({					\
+		int ___r = cond;		\
+		if (WARN_ON_ONCE(___r))		\
+			ftrace_kill();		\
+		___r;				\
+	})
+
+/* hash bits for specific function selection */
+#define FTRACE_HASH_DEFAULT_BITS 10
+#define FTRACE_HASH_MAX_BITS 12
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+#define INIT_OPS_HASH(opsname)	\
+	.func_hash		= &opsname.local_hash,			\
+	.local_hash.regex_lock	= __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
+#else
+#define INIT_OPS_HASH(opsname)
+#endif
+
+enum {
+	FTRACE_MODIFY_ENABLE_FL		= (1 << 0),
+	FTRACE_MODIFY_MAY_SLEEP_FL	= (1 << 1),
+};
+
+struct ftrace_ops ftrace_list_end __read_mostly = {
+	.func		= ftrace_stub,
+	.flags		= FTRACE_OPS_FL_STUB,
+	INIT_OPS_HASH(ftrace_list_end)
+};
+
+/* ftrace_enabled is a method to turn ftrace on or off */
+int ftrace_enabled __read_mostly;
+static int __maybe_unused last_ftrace_enabled;
+
+/* Current function tracing op */
+struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
+/* What to set function_trace_op to */
+static struct ftrace_ops *set_function_trace_op;
+
+static bool ftrace_pids_enabled(struct ftrace_ops *ops)
+{
+	struct trace_array *tr;
+
+	if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
+		return false;
+
+	tr = ops->private;
+
+	return tr->function_pids != NULL || tr->function_no_pids != NULL;
+}
+
+static void ftrace_update_trampoline(struct ftrace_ops *ops);
+
+/*
+ * ftrace_disabled is set when an anomaly is discovered.
+ * ftrace_disabled is much stronger than ftrace_enabled.
+ */
+static int ftrace_disabled __read_mostly;
+
+DEFINE_MUTEX(ftrace_lock);
+
+struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
+ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
+struct ftrace_ops global_ops;
+
+/* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */
+void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
+			  struct ftrace_ops *op, struct ftrace_regs *fregs);
+
+static inline void ftrace_ops_init(struct ftrace_ops *ops)
+{
+#ifdef CONFIG_DYNAMIC_FTRACE
+	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
+		mutex_init(&ops->local_hash.regex_lock);
+		ops->func_hash = &ops->local_hash;
+		ops->flags |= FTRACE_OPS_FL_INITIALIZED;
+	}
+#endif
+}
+
+static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
+			    struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	struct trace_array *tr = op->private;
+	int pid;
+
+	if (tr) {
+		pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
+		if (pid == FTRACE_PID_IGNORE)
+			return;
+		if (pid != FTRACE_PID_TRACE &&
+		    pid != current->pid)
+			return;
+	}
+
+	op->saved_func(ip, parent_ip, op, fregs);
+}
+
+static void ftrace_sync_ipi(void *data)
+{
+	/* Probably not needed, but do it anyway */
+	smp_rmb();
+}
+
+static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
+{
+	/*
+	 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
+	 * then it needs to call the list anyway.
+	 */
+	if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
+	    FTRACE_FORCE_LIST_FUNC)
+		return ftrace_ops_list_func;
+
+	return ftrace_ops_get_func(ops);
+}
+
+static void update_ftrace_function(void)
+{
+	ftrace_func_t func;
+
+	/*
+	 * Prepare the ftrace_ops that the arch callback will use.
+	 * If there's only one ftrace_ops registered, the ftrace_ops_list
+	 * will point to the ops we want.
+	 */
+	set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
+						lockdep_is_held(&ftrace_lock));
+
+	/* If there's no ftrace_ops registered, just call the stub function */
+	if (set_function_trace_op == &ftrace_list_end) {
+		func = ftrace_stub;
+
+	/*
+	 * If we are at the end of the list and this ops is
+	 * recursion safe and not dynamic and the arch supports passing ops,
+	 * then have the mcount trampoline call the function directly.
+	 */
+	} else if (rcu_dereference_protected(ftrace_ops_list->next,
+			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
+		func = ftrace_ops_get_list_func(ftrace_ops_list);
+
+	} else {
+		/* Just use the default ftrace_ops */
+		set_function_trace_op = &ftrace_list_end;
+		func = ftrace_ops_list_func;
+	}
+
+	update_function_graph_func();
+
+	/* If there's no change, then do nothing more here */
+	if (ftrace_trace_function == func)
+		return;
+
+	/*
+	 * If we are using the list function, it doesn't care
+	 * about the function_trace_ops.
+	 */
+	if (func == ftrace_ops_list_func) {
+		ftrace_trace_function = func;
+		/*
+		 * Don't even bother setting function_trace_ops,
+		 * it would be racy to do so anyway.
+		 */
+		return;
+	}
+
+#ifndef CONFIG_DYNAMIC_FTRACE
+	/*
+	 * For static tracing, we need to be a bit more careful.
+	 * The function change takes affect immediately. Thus,
+	 * we need to coordinate the setting of the function_trace_ops
+	 * with the setting of the ftrace_trace_function.
+	 *
+	 * Set the function to the list ops, which will call the
+	 * function we want, albeit indirectly, but it handles the
+	 * ftrace_ops and doesn't depend on function_trace_op.
+	 */
+	ftrace_trace_function = ftrace_ops_list_func;
+	/*
+	 * Make sure all CPUs see this. Yes this is slow, but static
+	 * tracing is slow and nasty to have enabled.
+	 */
+	synchronize_rcu_tasks_rude();
+	/* Now all cpus are using the list ops. */
+	function_trace_op = set_function_trace_op;
+	/* Make sure the function_trace_op is visible on all CPUs */
+	smp_wmb();
+	/* Nasty way to force a rmb on all cpus */
+	smp_call_function(ftrace_sync_ipi, NULL, 1);
+	/* OK, we are all set to update the ftrace_trace_function now! */
+#endif /* !CONFIG_DYNAMIC_FTRACE */
+
+	ftrace_trace_function = func;
+}
+
+static void add_ftrace_ops(struct ftrace_ops __rcu **list,
+			   struct ftrace_ops *ops)
+{
+	rcu_assign_pointer(ops->next, *list);
+
+	/*
+	 * We are entering ops into the list but another
+	 * CPU might be walking that list. We need to make sure
+	 * the ops->next pointer is valid before another CPU sees
+	 * the ops pointer included into the list.
+	 */
+	rcu_assign_pointer(*list, ops);
+}
+
+static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
+			     struct ftrace_ops *ops)
+{
+	struct ftrace_ops **p;
+
+	/*
+	 * If we are removing the last function, then simply point
+	 * to the ftrace_stub.
+	 */
+	if (rcu_dereference_protected(*list,
+			lockdep_is_held(&ftrace_lock)) == ops &&
+	    rcu_dereference_protected(ops->next,
+			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
+		*list = &ftrace_list_end;
+		return 0;
+	}
+
+	for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
+		if (*p == ops)
+			break;
+
+	if (*p != ops)
+		return -1;
+
+	*p = (*p)->next;
+	return 0;
+}
+
+static void ftrace_update_trampoline(struct ftrace_ops *ops);
+
+int __register_ftrace_function(struct ftrace_ops *ops)
+{
+	if (ops->flags & FTRACE_OPS_FL_DELETED)
+		return -EINVAL;
+
+	if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
+		return -EBUSY;
+
+#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+	/*
+	 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
+	 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
+	 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
+	 */
+	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
+	    !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
+		return -EINVAL;
+
+	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
+		ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
+#endif
+	if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
+		return -EBUSY;
+
+	if (!is_kernel_core_data((unsigned long)ops))
+		ops->flags |= FTRACE_OPS_FL_DYNAMIC;
+
+	add_ftrace_ops(&ftrace_ops_list, ops);
+
+	/* Always save the function, and reset at unregistering */
+	ops->saved_func = ops->func;
+
+	if (ftrace_pids_enabled(ops))
+		ops->func = ftrace_pid_func;
+
+	ftrace_update_trampoline(ops);
+
+	if (ftrace_enabled)
+		update_ftrace_function();
+
+	return 0;
+}
+
+int __unregister_ftrace_function(struct ftrace_ops *ops)
+{
+	int ret;
+
+	if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
+		return -EBUSY;
+
+	ret = remove_ftrace_ops(&ftrace_ops_list, ops);
+
+	if (ret < 0)
+		return ret;
+
+	if (ftrace_enabled)
+		update_ftrace_function();
+
+	ops->func = ops->saved_func;
+
+	return 0;
+}
+
+static void ftrace_update_pid_func(void)
+{
+	struct ftrace_ops *op;
+
+	/* Only do something if we are tracing something */
+	if (ftrace_trace_function == ftrace_stub)
+		return;
+
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		if (op->flags & FTRACE_OPS_FL_PID) {
+			op->func = ftrace_pids_enabled(op) ?
+				ftrace_pid_func : op->saved_func;
+			ftrace_update_trampoline(op);
+		}
+	} while_for_each_ftrace_op(op);
+
+	update_ftrace_function();
+}
+
+#ifdef CONFIG_FUNCTION_PROFILER
+struct ftrace_profile {
+	struct hlist_node		node;
+	unsigned long			ip;
+	unsigned long			counter;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	unsigned long long		time;
+	unsigned long long		time_squared;
+#endif
+};
+
+struct ftrace_profile_page {
+	struct ftrace_profile_page	*next;
+	unsigned long			index;
+	struct ftrace_profile		records[];
+};
+
+struct ftrace_profile_stat {
+	atomic_t			disabled;
+	struct hlist_head		*hash;
+	struct ftrace_profile_page	*pages;
+	struct ftrace_profile_page	*start;
+	struct tracer_stat		stat;
+};
+
+#define PROFILE_RECORDS_SIZE						\
+	(PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
+
+#define PROFILES_PER_PAGE					\
+	(PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
+
+static int ftrace_profile_enabled __read_mostly;
+
+/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
+static DEFINE_MUTEX(ftrace_profile_lock);
+
+static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
+
+#define FTRACE_PROFILE_HASH_BITS 10
+#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
+
+static void *
+function_stat_next(void *v, int idx)
+{
+	struct ftrace_profile *rec = v;
+	struct ftrace_profile_page *pg;
+
+	pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
+
+ again:
+	if (idx != 0)
+		rec++;
+
+	if ((void *)rec >= (void *)&pg->records[pg->index]) {
+		pg = pg->next;
+		if (!pg)
+			return NULL;
+		rec = &pg->records[0];
+		if (!rec->counter)
+			goto again;
+	}
+
+	return rec;
+}
+
+static void *function_stat_start(struct tracer_stat *trace)
+{
+	struct ftrace_profile_stat *stat =
+		container_of(trace, struct ftrace_profile_stat, stat);
+
+	if (!stat || !stat->start)
+		return NULL;
+
+	return function_stat_next(&stat->start->records[0], 0);
+}
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+/* function graph compares on total time */
+static int function_stat_cmp(const void *p1, const void *p2)
+{
+	const struct ftrace_profile *a = p1;
+	const struct ftrace_profile *b = p2;
+
+	if (a->time < b->time)
+		return -1;
+	if (a->time > b->time)
+		return 1;
+	else
+		return 0;
+}
+#else
+/* not function graph compares against hits */
+static int function_stat_cmp(const void *p1, const void *p2)
+{
+	const struct ftrace_profile *a = p1;
+	const struct ftrace_profile *b = p2;
+
+	if (a->counter < b->counter)
+		return -1;
+	if (a->counter > b->counter)
+		return 1;
+	else
+		return 0;
+}
+#endif
+
+static int function_stat_headers(struct seq_file *m)
+{
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	seq_puts(m, "  Function                               "
+		 "Hit    Time            Avg             s^2\n"
+		    "  --------                               "
+		 "---    ----            ---             ---\n");
+#else
+	seq_puts(m, "  Function                               Hit\n"
+		    "  --------                               ---\n");
+#endif
+	return 0;
+}
+
+static int function_stat_show(struct seq_file *m, void *v)
+{
+	struct ftrace_profile *rec = v;
+	char str[KSYM_SYMBOL_LEN];
+	int ret = 0;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	static struct trace_seq s;
+	unsigned long long avg;
+	unsigned long long stddev;
+#endif
+	mutex_lock(&ftrace_profile_lock);
+
+	/* we raced with function_profile_reset() */
+	if (unlikely(rec->counter == 0)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	avg = div64_ul(rec->time, rec->counter);
+	if (tracing_thresh && (avg < tracing_thresh))
+		goto out;
+#endif
+
+	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
+	seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	seq_puts(m, "    ");
+
+	/* Sample standard deviation (s^2) */
+	if (rec->counter <= 1)
+		stddev = 0;
+	else {
+		/*
+		 * Apply Welford's method:
+		 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
+		 */
+		stddev = rec->counter * rec->time_squared -
+			 rec->time * rec->time;
+
+		/*
+		 * Divide only 1000 for ns^2 -> us^2 conversion.
+		 * trace_print_graph_duration will divide 1000 again.
+		 */
+		stddev = div64_ul(stddev,
+				  rec->counter * (rec->counter - 1) * 1000);
+	}
+
+	trace_seq_init(&s);
+	trace_print_graph_duration(rec->time, &s);
+	trace_seq_puts(&s, "    ");
+	trace_print_graph_duration(avg, &s);
+	trace_seq_puts(&s, "    ");
+	trace_print_graph_duration(stddev, &s);
+	trace_print_seq(m, &s);
+#endif
+	seq_putc(m, '\n');
+out:
+	mutex_unlock(&ftrace_profile_lock);
+
+	return ret;
+}
+
+static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
+{
+	struct ftrace_profile_page *pg;
+
+	pg = stat->pages = stat->start;
+
+	while (pg) {
+		memset(pg->records, 0, PROFILE_RECORDS_SIZE);
+		pg->index = 0;
+		pg = pg->next;
+	}
+
+	memset(stat->hash, 0,
+	       FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
+}
+
+static int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
+{
+	struct ftrace_profile_page *pg;
+	int functions;
+	int pages;
+	int i;
+
+	/* If we already allocated, do nothing */
+	if (stat->pages)
+		return 0;
+
+	stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
+	if (!stat->pages)
+		return -ENOMEM;
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+	functions = ftrace_update_tot_cnt;
+#else
+	/*
+	 * We do not know the number of functions that exist because
+	 * dynamic tracing is what counts them. With past experience
+	 * we have around 20K functions. That should be more than enough.
+	 * It is highly unlikely we will execute every function in
+	 * the kernel.
+	 */
+	functions = 20000;
+#endif
+
+	pg = stat->start = stat->pages;
+
+	pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
+
+	for (i = 1; i < pages; i++) {
+		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
+		if (!pg->next)
+			goto out_free;
+		pg = pg->next;
+	}
+
+	return 0;
+
+ out_free:
+	pg = stat->start;
+	while (pg) {
+		unsigned long tmp = (unsigned long)pg;
+
+		pg = pg->next;
+		free_page(tmp);
+	}
+
+	stat->pages = NULL;
+	stat->start = NULL;
+
+	return -ENOMEM;
+}
+
+static int ftrace_profile_init_cpu(int cpu)
+{
+	struct ftrace_profile_stat *stat;
+	int size;
+
+	stat = &per_cpu(ftrace_profile_stats, cpu);
+
+	if (stat->hash) {
+		/* If the profile is already created, simply reset it */
+		ftrace_profile_reset(stat);
+		return 0;
+	}
+
+	/*
+	 * We are profiling all functions, but usually only a few thousand
+	 * functions are hit. We'll make a hash of 1024 items.
+	 */
+	size = FTRACE_PROFILE_HASH_SIZE;
+
+	stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
+
+	if (!stat->hash)
+		return -ENOMEM;
+
+	/* Preallocate the function profiling pages */
+	if (ftrace_profile_pages_init(stat) < 0) {
+		kfree(stat->hash);
+		stat->hash = NULL;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int ftrace_profile_init(void)
+{
+	int cpu;
+	int ret = 0;
+
+	for_each_possible_cpu(cpu) {
+		ret = ftrace_profile_init_cpu(cpu);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+/* interrupts must be disabled */
+static struct ftrace_profile *
+ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
+{
+	struct ftrace_profile *rec;
+	struct hlist_head *hhd;
+	unsigned long key;
+
+	key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
+	hhd = &stat->hash[key];
+
+	if (hlist_empty(hhd))
+		return NULL;
+
+	hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
+		if (rec->ip == ip)
+			return rec;
+	}
+
+	return NULL;
+}
+
+static void ftrace_add_profile(struct ftrace_profile_stat *stat,
+			       struct ftrace_profile *rec)
+{
+	unsigned long key;
+
+	key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
+	hlist_add_head_rcu(&rec->node, &stat->hash[key]);
+}
+
+/*
+ * The memory is already allocated, this simply finds a new record to use.
+ */
+static struct ftrace_profile *
+ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
+{
+	struct ftrace_profile *rec = NULL;
+
+	/* prevent recursion (from NMIs) */
+	if (atomic_inc_return(&stat->disabled) != 1)
+		goto out;
+
+	/*
+	 * Try to find the function again since an NMI
+	 * could have added it
+	 */
+	rec = ftrace_find_profiled_func(stat, ip);
+	if (rec)
+		goto out;
+
+	if (stat->pages->index == PROFILES_PER_PAGE) {
+		if (!stat->pages->next)
+			goto out;
+		stat->pages = stat->pages->next;
+	}
+
+	rec = &stat->pages->records[stat->pages->index++];
+	rec->ip = ip;
+	ftrace_add_profile(stat, rec);
+
+ out:
+	atomic_dec(&stat->disabled);
+
+	return rec;
+}
+
+static void
+function_profile_call(unsigned long ip, unsigned long parent_ip,
+		      struct ftrace_ops *ops, struct ftrace_regs *fregs)
+{
+	struct ftrace_profile_stat *stat;
+	struct ftrace_profile *rec;
+	unsigned long flags;
+
+	if (!ftrace_profile_enabled)
+		return;
+
+	local_irq_save(flags);
+
+	stat = this_cpu_ptr(&ftrace_profile_stats);
+	if (!stat->hash || !ftrace_profile_enabled)
+		goto out;
+
+	rec = ftrace_find_profiled_func(stat, ip);
+	if (!rec) {
+		rec = ftrace_profile_alloc(stat, ip);
+		if (!rec)
+			goto out;
+	}
+
+	rec->counter++;
+ out:
+	local_irq_restore(flags);
+}
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+static bool fgraph_graph_time = true;
+
+void ftrace_graph_graph_time_control(bool enable)
+{
+	fgraph_graph_time = enable;
+}
+
+static int profile_graph_entry(struct ftrace_graph_ent *trace)
+{
+	struct ftrace_ret_stack *ret_stack;
+
+	function_profile_call(trace->func, 0, NULL, NULL);
+
+	/* If function graph is shutting down, ret_stack can be NULL */
+	if (!current->ret_stack)
+		return 0;
+
+	ret_stack = ftrace_graph_get_ret_stack(current, 0);
+	if (ret_stack)
+		ret_stack->subtime = 0;
+
+	return 1;
+}
+
+static void profile_graph_return(struct ftrace_graph_ret *trace)
+{
+	struct ftrace_ret_stack *ret_stack;
+	struct ftrace_profile_stat *stat;
+	unsigned long long calltime;
+	struct ftrace_profile *rec;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	stat = this_cpu_ptr(&ftrace_profile_stats);
+	if (!stat->hash || !ftrace_profile_enabled)
+		goto out;
+
+	/* If the calltime was zero'd ignore it */
+	if (!trace->calltime)
+		goto out;
+
+	calltime = trace->rettime - trace->calltime;
+
+	if (!fgraph_graph_time) {
+
+		/* Append this call time to the parent time to subtract */
+		ret_stack = ftrace_graph_get_ret_stack(current, 1);
+		if (ret_stack)
+			ret_stack->subtime += calltime;
+
+		ret_stack = ftrace_graph_get_ret_stack(current, 0);
+		if (ret_stack && ret_stack->subtime < calltime)
+			calltime -= ret_stack->subtime;
+		else
+			calltime = 0;
+	}
+
+	rec = ftrace_find_profiled_func(stat, trace->func);
+	if (rec) {
+		rec->time += calltime;
+		rec->time_squared += calltime * calltime;
+	}
+
+ out:
+	local_irq_restore(flags);
+}
+
+static struct fgraph_ops fprofiler_ops = {
+	.entryfunc = &profile_graph_entry,
+	.retfunc = &profile_graph_return,
+};
+
+static int register_ftrace_profiler(void)
+{
+	return register_ftrace_graph(&fprofiler_ops);
+}
+
+static void unregister_ftrace_profiler(void)
+{
+	unregister_ftrace_graph(&fprofiler_ops);
+}
+#else
+static struct ftrace_ops ftrace_profile_ops __read_mostly = {
+	.func		= function_profile_call,
+	.flags		= FTRACE_OPS_FL_INITIALIZED,
+	INIT_OPS_HASH(ftrace_profile_ops)
+};
+
+static int register_ftrace_profiler(void)
+{
+	return register_ftrace_function(&ftrace_profile_ops);
+}
+
+static void unregister_ftrace_profiler(void)
+{
+	unregister_ftrace_function(&ftrace_profile_ops);
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+static ssize_t
+ftrace_profile_write(struct file *filp, const char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	val = !!val;
+
+	mutex_lock(&ftrace_profile_lock);
+	if (ftrace_profile_enabled ^ val) {
+		if (val) {
+			ret = ftrace_profile_init();
+			if (ret < 0) {
+				cnt = ret;
+				goto out;
+			}
+
+			ret = register_ftrace_profiler();
+			if (ret < 0) {
+				cnt = ret;
+				goto out;
+			}
+			ftrace_profile_enabled = 1;
+		} else {
+			ftrace_profile_enabled = 0;
+			/*
+			 * unregister_ftrace_profiler calls stop_machine
+			 * so this acts like an synchronize_rcu.
+			 */
+			unregister_ftrace_profiler();
+		}
+	}
+ out:
+	mutex_unlock(&ftrace_profile_lock);
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static ssize_t
+ftrace_profile_read(struct file *filp, char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	char buf[64];		/* big enough to hold a number */
+	int r;
+
+	r = sprintf(buf, "%u\n", ftrace_profile_enabled);
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static const struct file_operations ftrace_profile_fops = {
+	.open		= tracing_open_generic,
+	.read		= ftrace_profile_read,
+	.write		= ftrace_profile_write,
+	.llseek		= default_llseek,
+};
+
+/* used to initialize the real stat files */
+static struct tracer_stat function_stats __initdata = {
+	.name		= "functions",
+	.stat_start	= function_stat_start,
+	.stat_next	= function_stat_next,
+	.stat_cmp	= function_stat_cmp,
+	.stat_headers	= function_stat_headers,
+	.stat_show	= function_stat_show
+};
+
+static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
+{
+	struct ftrace_profile_stat *stat;
+	char *name;
+	int ret;
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		stat = &per_cpu(ftrace_profile_stats, cpu);
+
+		name = kasprintf(GFP_KERNEL, "function%d", cpu);
+		if (!name) {
+			/*
+			 * The files created are permanent, if something happens
+			 * we still do not free memory.
+			 */
+			WARN(1,
+			     "Could not allocate stat file for cpu %d\n",
+			     cpu);
+			return;
+		}
+		stat->stat = function_stats;
+		stat->stat.name = name;
+		ret = register_stat_tracer(&stat->stat);
+		if (ret) {
+			WARN(1,
+			     "Could not register function stat for cpu %d\n",
+			     cpu);
+			kfree(name);
+			return;
+		}
+	}
+
+	trace_create_file("function_profile_enabled",
+			  TRACE_MODE_WRITE, d_tracer, NULL,
+			  &ftrace_profile_fops);
+}
+
+#else /* CONFIG_FUNCTION_PROFILER */
+static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
+{
+}
+#endif /* CONFIG_FUNCTION_PROFILER */
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+static struct ftrace_ops *removed_ops;
+
+/*
+ * Set when doing a global update, like enabling all recs or disabling them.
+ * It is not set when just updating a single ftrace_ops.
+ */
+static bool update_all_ops;
+
+#ifndef CONFIG_FTRACE_MCOUNT_RECORD
+# error Dynamic ftrace depends on MCOUNT_RECORD
+#endif
+
+struct ftrace_func_probe {
+	struct ftrace_probe_ops	*probe_ops;
+	struct ftrace_ops	ops;
+	struct trace_array	*tr;
+	struct list_head	list;
+	void			*data;
+	int			ref;
+};
+
+/*
+ * We make these constant because no one should touch them,
+ * but they are used as the default "empty hash", to avoid allocating
+ * it all the time. These are in a read only section such that if
+ * anyone does try to modify it, it will cause an exception.
+ */
+static const struct hlist_head empty_buckets[1];
+static const struct ftrace_hash empty_hash = {
+	.buckets = (struct hlist_head *)empty_buckets,
+};
+#define EMPTY_HASH	((struct ftrace_hash *)&empty_hash)
+
+struct ftrace_ops global_ops = {
+	.func				= ftrace_stub,
+	.local_hash.notrace_hash	= EMPTY_HASH,
+	.local_hash.filter_hash		= EMPTY_HASH,
+	INIT_OPS_HASH(global_ops)
+	.flags				= FTRACE_OPS_FL_INITIALIZED |
+					  FTRACE_OPS_FL_PID,
+};
+
+/*
+ * Used by the stack unwinder to know about dynamic ftrace trampolines.
+ */
+struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
+{
+	struct ftrace_ops *op = NULL;
+
+	/*
+	 * Some of the ops may be dynamically allocated,
+	 * they are freed after a synchronize_rcu().
+	 */
+	preempt_disable_notrace();
+
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		/*
+		 * This is to check for dynamically allocated trampolines.
+		 * Trampolines that are in kernel text will have
+		 * core_kernel_text() return true.
+		 */
+		if (op->trampoline && op->trampoline_size)
+			if (addr >= op->trampoline &&
+			    addr < op->trampoline + op->trampoline_size) {
+				preempt_enable_notrace();
+				return op;
+			}
+	} while_for_each_ftrace_op(op);
+	preempt_enable_notrace();
+
+	return NULL;
+}
+
+/*
+ * This is used by __kernel_text_address() to return true if the
+ * address is on a dynamically allocated trampoline that would
+ * not return true for either core_kernel_text() or
+ * is_module_text_address().
+ */
+bool is_ftrace_trampoline(unsigned long addr)
+{
+	return ftrace_ops_trampoline(addr) != NULL;
+}
+
+struct ftrace_page {
+	struct ftrace_page	*next;
+	struct dyn_ftrace	*records;
+	int			index;
+	int			order;
+};
+
+#define ENTRY_SIZE sizeof(struct dyn_ftrace)
+#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
+
+static struct ftrace_page	*ftrace_pages_start;
+static struct ftrace_page	*ftrace_pages;
+
+static __always_inline unsigned long
+ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
+{
+	if (hash->size_bits > 0)
+		return hash_long(ip, hash->size_bits);
+
+	return 0;
+}
+
+/* Only use this function if ftrace_hash_empty() has already been tested */
+static __always_inline struct ftrace_func_entry *
+__ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
+{
+	unsigned long key;
+	struct ftrace_func_entry *entry;
+	struct hlist_head *hhd;
+
+	key = ftrace_hash_key(hash, ip);
+	hhd = &hash->buckets[key];
+
+	hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
+		if (entry->ip == ip)
+			return entry;
+	}
+	return NULL;
+}
+
+/**
+ * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
+ * @hash: The hash to look at
+ * @ip: The instruction pointer to test
+ *
+ * Search a given @hash to see if a given instruction pointer (@ip)
+ * exists in it.
+ *
+ * Returns the entry that holds the @ip if found. NULL otherwise.
+ */
+struct ftrace_func_entry *
+ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
+{
+	if (ftrace_hash_empty(hash))
+		return NULL;
+
+	return __ftrace_lookup_ip(hash, ip);
+}
+
+static void __add_hash_entry(struct ftrace_hash *hash,
+			     struct ftrace_func_entry *entry)
+{
+	struct hlist_head *hhd;
+	unsigned long key;
+
+	key = ftrace_hash_key(hash, entry->ip);
+	hhd = &hash->buckets[key];
+	hlist_add_head(&entry->hlist, hhd);
+	hash->count++;
+}
+
+static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
+{
+	struct ftrace_func_entry *entry;
+
+	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->ip = ip;
+	__add_hash_entry(hash, entry);
+
+	return 0;
+}
+
+static void
+free_hash_entry(struct ftrace_hash *hash,
+		  struct ftrace_func_entry *entry)
+{
+	hlist_del(&entry->hlist);
+	kfree(entry);
+	hash->count--;
+}
+
+static void
+remove_hash_entry(struct ftrace_hash *hash,
+		  struct ftrace_func_entry *entry)
+{
+	hlist_del_rcu(&entry->hlist);
+	hash->count--;
+}
+
+static void ftrace_hash_clear(struct ftrace_hash *hash)
+{
+	struct hlist_head *hhd;
+	struct hlist_node *tn;
+	struct ftrace_func_entry *entry;
+	int size = 1 << hash->size_bits;
+	int i;
+
+	if (!hash->count)
+		return;
+
+	for (i = 0; i < size; i++) {
+		hhd = &hash->buckets[i];
+		hlist_for_each_entry_safe(entry, tn, hhd, hlist)
+			free_hash_entry(hash, entry);
+	}
+	FTRACE_WARN_ON(hash->count);
+}
+
+static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
+{
+	list_del(&ftrace_mod->list);
+	kfree(ftrace_mod->module);
+	kfree(ftrace_mod->func);
+	kfree(ftrace_mod);
+}
+
+static void clear_ftrace_mod_list(struct list_head *head)
+{
+	struct ftrace_mod_load *p, *n;
+
+	/* stack tracer isn't supported yet */
+	if (!head)
+		return;
+
+	mutex_lock(&ftrace_lock);
+	list_for_each_entry_safe(p, n, head, list)
+		free_ftrace_mod(p);
+	mutex_unlock(&ftrace_lock);
+}
+
+static void free_ftrace_hash(struct ftrace_hash *hash)
+{
+	if (!hash || hash == EMPTY_HASH)
+		return;
+	ftrace_hash_clear(hash);
+	kfree(hash->buckets);
+	kfree(hash);
+}
+
+static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
+{
+	struct ftrace_hash *hash;
+
+	hash = container_of(rcu, struct ftrace_hash, rcu);
+	free_ftrace_hash(hash);
+}
+
+static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
+{
+	if (!hash || hash == EMPTY_HASH)
+		return;
+	call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
+}
+
+/**
+ * ftrace_free_filter - remove all filters for an ftrace_ops
+ * @ops - the ops to remove the filters from
+ */
+void ftrace_free_filter(struct ftrace_ops *ops)
+{
+	ftrace_ops_init(ops);
+	free_ftrace_hash(ops->func_hash->filter_hash);
+	free_ftrace_hash(ops->func_hash->notrace_hash);
+}
+EXPORT_SYMBOL_GPL(ftrace_free_filter);
+
+static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
+{
+	struct ftrace_hash *hash;
+	int size;
+
+	hash = kzalloc(sizeof(*hash), GFP_KERNEL);
+	if (!hash)
+		return NULL;
+
+	size = 1 << size_bits;
+	hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
+
+	if (!hash->buckets) {
+		kfree(hash);
+		return NULL;
+	}
+
+	hash->size_bits = size_bits;
+
+	return hash;
+}
+
+
+static int ftrace_add_mod(struct trace_array *tr,
+			  const char *func, const char *module,
+			  int enable)
+{
+	struct ftrace_mod_load *ftrace_mod;
+	struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
+
+	ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
+	if (!ftrace_mod)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&ftrace_mod->list);
+	ftrace_mod->func = kstrdup(func, GFP_KERNEL);
+	ftrace_mod->module = kstrdup(module, GFP_KERNEL);
+	ftrace_mod->enable = enable;
+
+	if (!ftrace_mod->func || !ftrace_mod->module)
+		goto out_free;
+
+	list_add(&ftrace_mod->list, mod_head);
+
+	return 0;
+
+ out_free:
+	free_ftrace_mod(ftrace_mod);
+
+	return -ENOMEM;
+}
+
+static struct ftrace_hash *
+alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
+{
+	struct ftrace_func_entry *entry;
+	struct ftrace_hash *new_hash;
+	int size;
+	int ret;
+	int i;
+
+	new_hash = alloc_ftrace_hash(size_bits);
+	if (!new_hash)
+		return NULL;
+
+	if (hash)
+		new_hash->flags = hash->flags;
+
+	/* Empty hash? */
+	if (ftrace_hash_empty(hash))
+		return new_hash;
+
+	size = 1 << hash->size_bits;
+	for (i = 0; i < size; i++) {
+		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
+			ret = add_hash_entry(new_hash, entry->ip);
+			if (ret < 0)
+				goto free_hash;
+		}
+	}
+
+	FTRACE_WARN_ON(new_hash->count != hash->count);
+
+	return new_hash;
+
+ free_hash:
+	free_ftrace_hash(new_hash);
+	return NULL;
+}
+
+static void
+ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
+static void
+ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
+
+static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
+				       struct ftrace_hash *new_hash);
+
+static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
+{
+	struct ftrace_func_entry *entry;
+	struct ftrace_hash *new_hash;
+	struct hlist_head *hhd;
+	struct hlist_node *tn;
+	int bits = 0;
+	int i;
+
+	/*
+	 * Use around half the size (max bit of it), but
+	 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
+	 */
+	bits = fls(size / 2);
+
+	/* Don't allocate too much */
+	if (bits > FTRACE_HASH_MAX_BITS)
+		bits = FTRACE_HASH_MAX_BITS;
+
+	new_hash = alloc_ftrace_hash(bits);
+	if (!new_hash)
+		return NULL;
+
+	new_hash->flags = src->flags;
+
+	size = 1 << src->size_bits;
+	for (i = 0; i < size; i++) {
+		hhd = &src->buckets[i];
+		hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
+			remove_hash_entry(src, entry);
+			__add_hash_entry(new_hash, entry);
+		}
+	}
+	return new_hash;
+}
+
+static struct ftrace_hash *
+__ftrace_hash_move(struct ftrace_hash *src)
+{
+	int size = src->count;
+
+	/*
+	 * If the new source is empty, just return the empty_hash.
+	 */
+	if (ftrace_hash_empty(src))
+		return EMPTY_HASH;
+
+	return dup_hash(src, size);
+}
+
+static int
+ftrace_hash_move(struct ftrace_ops *ops, int enable,
+		 struct ftrace_hash **dst, struct ftrace_hash *src)
+{
+	struct ftrace_hash *new_hash;
+	int ret;
+
+	/* Reject setting notrace hash on IPMODIFY ftrace_ops */
+	if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
+		return -EINVAL;
+
+	new_hash = __ftrace_hash_move(src);
+	if (!new_hash)
+		return -ENOMEM;
+
+	/* Make sure this can be applied if it is IPMODIFY ftrace_ops */
+	if (enable) {
+		/* IPMODIFY should be updated only when filter_hash updating */
+		ret = ftrace_hash_ipmodify_update(ops, new_hash);
+		if (ret < 0) {
+			free_ftrace_hash(new_hash);
+			return ret;
+		}
+	}
+
+	/*
+	 * Remove the current set, update the hash and add
+	 * them back.
+	 */
+	ftrace_hash_rec_disable_modify(ops, enable);
+
+	rcu_assign_pointer(*dst, new_hash);
+
+	ftrace_hash_rec_enable_modify(ops, enable);
+
+	return 0;
+}
+
+static bool hash_contains_ip(unsigned long ip,
+			     struct ftrace_ops_hash *hash)
+{
+	/*
+	 * The function record is a match if it exists in the filter
+	 * hash and not in the notrace hash. Note, an empty hash is
+	 * considered a match for the filter hash, but an empty
+	 * notrace hash is considered not in the notrace hash.
+	 */
+	return (ftrace_hash_empty(hash->filter_hash) ||
+		__ftrace_lookup_ip(hash->filter_hash, ip)) &&
+		(ftrace_hash_empty(hash->notrace_hash) ||
+		 !__ftrace_lookup_ip(hash->notrace_hash, ip));
+}
+
+/*
+ * Test the hashes for this ops to see if we want to call
+ * the ops->func or not.
+ *
+ * It's a match if the ip is in the ops->filter_hash or
+ * the filter_hash does not exist or is empty,
+ *  AND
+ * the ip is not in the ops->notrace_hash.
+ *
+ * This needs to be called with preemption disabled as
+ * the hashes are freed with call_rcu().
+ */
+int
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
+{
+	struct ftrace_ops_hash hash;
+	int ret;
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+	/*
+	 * There's a small race when adding ops that the ftrace handler
+	 * that wants regs, may be called without them. We can not
+	 * allow that handler to be called if regs is NULL.
+	 */
+	if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
+		return 0;
+#endif
+
+	rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
+	rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
+
+	if (hash_contains_ip(ip, &hash))
+		ret = 1;
+	else
+		ret = 0;
+
+	return ret;
+}
+
+/*
+ * This is a double for. Do not use 'break' to break out of the loop,
+ * you must use a goto.
+ */
+#define do_for_each_ftrace_rec(pg, rec)					\
+	for (pg = ftrace_pages_start; pg; pg = pg->next) {		\
+		int _____i;						\
+		for (_____i = 0; _____i < pg->index; _____i++) {	\
+			rec = &pg->records[_____i];
+
+#define while_for_each_ftrace_rec()		\
+		}				\
+	}
+
+
+static int ftrace_cmp_recs(const void *a, const void *b)
+{
+	const struct dyn_ftrace *key = a;
+	const struct dyn_ftrace *rec = b;
+
+	if (key->flags < rec->ip)
+		return -1;
+	if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
+		return 1;
+	return 0;
+}
+
+static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
+{
+	struct ftrace_page *pg;
+	struct dyn_ftrace *rec = NULL;
+	struct dyn_ftrace key;
+
+	key.ip = start;
+	key.flags = end;	/* overload flags, as it is unsigned long */
+
+	for (pg = ftrace_pages_start; pg; pg = pg->next) {
+		if (pg->index == 0 ||
+		    end < pg->records[0].ip ||
+		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
+			continue;
+		rec = bsearch(&key, pg->records, pg->index,
+			      sizeof(struct dyn_ftrace),
+			      ftrace_cmp_recs);
+		if (rec)
+			break;
+	}
+	return rec;
+}
+
+/**
+ * ftrace_location_range - return the first address of a traced location
+ *	if it touches the given ip range
+ * @start: start of range to search.
+ * @end: end of range to search (inclusive). @end points to the last byte
+ *	to check.
+ *
+ * Returns rec->ip if the related ftrace location is a least partly within
+ * the given address range. That is, the first address of the instruction
+ * that is either a NOP or call to the function tracer. It checks the ftrace
+ * internal tables to determine if the address belongs or not.
+ */
+unsigned long ftrace_location_range(unsigned long start, unsigned long end)
+{
+	struct dyn_ftrace *rec;
+
+	rec = lookup_rec(start, end);
+	if (rec)
+		return rec->ip;
+
+	return 0;
+}
+
+/**
+ * ftrace_location - return the ftrace location
+ * @ip: the instruction pointer to check
+ *
+ * If @ip matches the ftrace location, return @ip.
+ * If @ip matches sym+0, return sym's ftrace location.
+ * Otherwise, return 0.
+ */
+unsigned long ftrace_location(unsigned long ip)
+{
+	struct dyn_ftrace *rec;
+	unsigned long offset;
+	unsigned long size;
+
+	rec = lookup_rec(ip, ip);
+	if (!rec) {
+		if (!kallsyms_lookup_size_offset(ip, &size, &offset))
+			goto out;
+
+		/* map sym+0 to __fentry__ */
+		if (!offset)
+			rec = lookup_rec(ip, ip + size - 1);
+	}
+
+	if (rec)
+		return rec->ip;
+
+out:
+	return 0;
+}
+
+/**
+ * ftrace_text_reserved - return true if range contains an ftrace location
+ * @start: start of range to search
+ * @end: end of range to search (inclusive). @end points to the last byte to check.
+ *
+ * Returns 1 if @start and @end contains a ftrace location.
+ * That is, the instruction that is either a NOP or call to
+ * the function tracer. It checks the ftrace internal tables to
+ * determine if the address belongs or not.
+ */
+int ftrace_text_reserved(const void *start, const void *end)
+{
+	unsigned long ret;
+
+	ret = ftrace_location_range((unsigned long)start,
+				    (unsigned long)end);
+
+	return (int)!!ret;
+}
+
+/* Test if ops registered to this rec needs regs */
+static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
+{
+	struct ftrace_ops *ops;
+	bool keep_regs = false;
+
+	for (ops = ftrace_ops_list;
+	     ops != &ftrace_list_end; ops = ops->next) {
+		/* pass rec in as regs to have non-NULL val */
+		if (ftrace_ops_test(ops, rec->ip, rec)) {
+			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
+				keep_regs = true;
+				break;
+			}
+		}
+	}
+
+	return  keep_regs;
+}
+
+static struct ftrace_ops *
+ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
+static struct ftrace_ops *
+ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
+static struct ftrace_ops *
+ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
+
+static bool skip_record(struct dyn_ftrace *rec)
+{
+	/*
+	 * At boot up, weak functions are set to disable. Function tracing
+	 * can be enabled before they are, and they still need to be disabled now.
+	 * If the record is disabled, still continue if it is marked as already
+	 * enabled (this is needed to keep the accounting working).
+	 */
+	return rec->flags & FTRACE_FL_DISABLED &&
+		!(rec->flags & FTRACE_FL_ENABLED);
+}
+
+static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
+				     int filter_hash,
+				     bool inc)
+{
+	struct ftrace_hash *hash;
+	struct ftrace_hash *other_hash;
+	struct ftrace_page *pg;
+	struct dyn_ftrace *rec;
+	bool update = false;
+	int count = 0;
+	int all = false;
+
+	/* Only update if the ops has been registered */
+	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+		return false;
+
+	/*
+	 * In the filter_hash case:
+	 *   If the count is zero, we update all records.
+	 *   Otherwise we just update the items in the hash.
+	 *
+	 * In the notrace_hash case:
+	 *   We enable the update in the hash.
+	 *   As disabling notrace means enabling the tracing,
+	 *   and enabling notrace means disabling, the inc variable
+	 *   gets inversed.
+	 */
+	if (filter_hash) {
+		hash = ops->func_hash->filter_hash;
+		other_hash = ops->func_hash->notrace_hash;
+		if (ftrace_hash_empty(hash))
+			all = true;
+	} else {
+		inc = !inc;
+		hash = ops->func_hash->notrace_hash;
+		other_hash = ops->func_hash->filter_hash;
+		/*
+		 * If the notrace hash has no items,
+		 * then there's nothing to do.
+		 */
+		if (ftrace_hash_empty(hash))
+			return false;
+	}
+
+	do_for_each_ftrace_rec(pg, rec) {
+		int in_other_hash = 0;
+		int in_hash = 0;
+		int match = 0;
+
+		if (skip_record(rec))
+			continue;
+
+		if (all) {
+			/*
+			 * Only the filter_hash affects all records.
+			 * Update if the record is not in the notrace hash.
+			 */
+			if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
+				match = 1;
+		} else {
+			in_hash = !!ftrace_lookup_ip(hash, rec->ip);
+			in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
+
+			/*
+			 * If filter_hash is set, we want to match all functions
+			 * that are in the hash but not in the other hash.
+			 *
+			 * If filter_hash is not set, then we are decrementing.
+			 * That means we match anything that is in the hash
+			 * and also in the other_hash. That is, we need to turn
+			 * off functions in the other hash because they are disabled
+			 * by this hash.
+			 */
+			if (filter_hash && in_hash && !in_other_hash)
+				match = 1;
+			else if (!filter_hash && in_hash &&
+				 (in_other_hash || ftrace_hash_empty(other_hash)))
+				match = 1;
+		}
+		if (!match)
+			continue;
+
+		if (inc) {
+			rec->flags++;
+			if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
+				return false;
+
+			if (ops->flags & FTRACE_OPS_FL_DIRECT)
+				rec->flags |= FTRACE_FL_DIRECT;
+
+			/*
+			 * If there's only a single callback registered to a
+			 * function, and the ops has a trampoline registered
+			 * for it, then we can call it directly.
+			 */
+			if (ftrace_rec_count(rec) == 1 && ops->trampoline)
+				rec->flags |= FTRACE_FL_TRAMP;
+			else
+				/*
+				 * If we are adding another function callback
+				 * to this function, and the previous had a
+				 * custom trampoline in use, then we need to go
+				 * back to the default trampoline.
+				 */
+				rec->flags &= ~FTRACE_FL_TRAMP;
+
+			/*
+			 * If any ops wants regs saved for this function
+			 * then all ops will get saved regs.
+			 */
+			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
+				rec->flags |= FTRACE_FL_REGS;
+		} else {
+			if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
+				return false;
+			rec->flags--;
+
+			/*
+			 * Only the internal direct_ops should have the
+			 * DIRECT flag set. Thus, if it is removing a
+			 * function, then that function should no longer
+			 * be direct.
+			 */
+			if (ops->flags & FTRACE_OPS_FL_DIRECT)
+				rec->flags &= ~FTRACE_FL_DIRECT;
+
+			/*
+			 * If the rec had REGS enabled and the ops that is
+			 * being removed had REGS set, then see if there is
+			 * still any ops for this record that wants regs.
+			 * If not, we can stop recording them.
+			 */
+			if (ftrace_rec_count(rec) > 0 &&
+			    rec->flags & FTRACE_FL_REGS &&
+			    ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
+				if (!test_rec_ops_needs_regs(rec))
+					rec->flags &= ~FTRACE_FL_REGS;
+			}
+
+			/*
+			 * The TRAMP needs to be set only if rec count
+			 * is decremented to one, and the ops that is
+			 * left has a trampoline. As TRAMP can only be
+			 * enabled if there is only a single ops attached
+			 * to it.
+			 */
+			if (ftrace_rec_count(rec) == 1 &&
+			    ftrace_find_tramp_ops_any_other(rec, ops))
+				rec->flags |= FTRACE_FL_TRAMP;
+			else
+				rec->flags &= ~FTRACE_FL_TRAMP;
+
+			/*
+			 * flags will be cleared in ftrace_check_record()
+			 * if rec count is zero.
+			 */
+		}
+		count++;
+
+		/* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
+		update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
+
+		/* Shortcut, if we handled all records, we are done. */
+		if (!all && count == hash->count)
+			return update;
+	} while_for_each_ftrace_rec();
+
+	return update;
+}
+
+static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
+				    int filter_hash)
+{
+	return __ftrace_hash_rec_update(ops, filter_hash, 0);
+}
+
+static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
+				   int filter_hash)
+{
+	return __ftrace_hash_rec_update(ops, filter_hash, 1);
+}
+
+static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
+					  int filter_hash, int inc)
+{
+	struct ftrace_ops *op;
+
+	__ftrace_hash_rec_update(ops, filter_hash, inc);
+
+	if (ops->func_hash != &global_ops.local_hash)
+		return;
+
+	/*
+	 * If the ops shares the global_ops hash, then we need to update
+	 * all ops that are enabled and use this hash.
+	 */
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		/* Already done */
+		if (op == ops)
+			continue;
+		if (op->func_hash == &global_ops.local_hash)
+			__ftrace_hash_rec_update(op, filter_hash, inc);
+	} while_for_each_ftrace_op(op);
+}
+
+static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
+					   int filter_hash)
+{
+	ftrace_hash_rec_update_modify(ops, filter_hash, 0);
+}
+
+static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
+					  int filter_hash)
+{
+	ftrace_hash_rec_update_modify(ops, filter_hash, 1);
+}
+
+/*
+ * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
+ * or no-needed to update, -EBUSY if it detects a conflict of the flag
+ * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
+ * Note that old_hash and new_hash has below meanings
+ *  - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
+ *  - If the hash is EMPTY_HASH, it hits nothing
+ *  - Anything else hits the recs which match the hash entries.
+ *
+ * DIRECT ops does not have IPMODIFY flag, but we still need to check it
+ * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
+ * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
+ * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
+ * the return value to the caller and eventually to the owner of the DIRECT
+ * ops.
+ */
+static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
+					 struct ftrace_hash *old_hash,
+					 struct ftrace_hash *new_hash)
+{
+	struct ftrace_page *pg;
+	struct dyn_ftrace *rec, *end = NULL;
+	int in_old, in_new;
+	bool is_ipmodify, is_direct;
+
+	/* Only update if the ops has been registered */
+	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+		return 0;
+
+	is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
+	is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
+
+	/* neither IPMODIFY nor DIRECT, skip */
+	if (!is_ipmodify && !is_direct)
+		return 0;
+
+	if (WARN_ON_ONCE(is_ipmodify && is_direct))
+		return 0;
+
+	/*
+	 * Since the IPMODIFY and DIRECT are very address sensitive
+	 * actions, we do not allow ftrace_ops to set all functions to new
+	 * hash.
+	 */
+	if (!new_hash || !old_hash)
+		return -EINVAL;
+
+	/* Update rec->flags */
+	do_for_each_ftrace_rec(pg, rec) {
+
+		if (rec->flags & FTRACE_FL_DISABLED)
+			continue;
+
+		/* We need to update only differences of filter_hash */
+		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
+		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
+		if (in_old == in_new)
+			continue;
+
+		if (in_new) {
+			if (rec->flags & FTRACE_FL_IPMODIFY) {
+				int ret;
+
+				/* Cannot have two ipmodify on same rec */
+				if (is_ipmodify)
+					goto rollback;
+
+				FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
+
+				/*
+				 * Another ops with IPMODIFY is already
+				 * attached. We are now attaching a direct
+				 * ops. Run SHARE_IPMODIFY_SELF, to check
+				 * whether sharing is supported.
+				 */
+				if (!ops->ops_func)
+					return -EBUSY;
+				ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
+				if (ret)
+					return ret;
+			} else if (is_ipmodify) {
+				rec->flags |= FTRACE_FL_IPMODIFY;
+			}
+		} else if (is_ipmodify) {
+			rec->flags &= ~FTRACE_FL_IPMODIFY;
+		}
+	} while_for_each_ftrace_rec();
+
+	return 0;
+
+rollback:
+	end = rec;
+
+	/* Roll back what we did above */
+	do_for_each_ftrace_rec(pg, rec) {
+
+		if (rec->flags & FTRACE_FL_DISABLED)
+			continue;
+
+		if (rec == end)
+			goto err_out;
+
+		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
+		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
+		if (in_old == in_new)
+			continue;
+
+		if (in_new)
+			rec->flags &= ~FTRACE_FL_IPMODIFY;
+		else
+			rec->flags |= FTRACE_FL_IPMODIFY;
+	} while_for_each_ftrace_rec();
+
+err_out:
+	return -EBUSY;
+}
+
+static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
+{
+	struct ftrace_hash *hash = ops->func_hash->filter_hash;
+
+	if (ftrace_hash_empty(hash))
+		hash = NULL;
+
+	return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
+}
+
+/* Disabling always succeeds */
+static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
+{
+	struct ftrace_hash *hash = ops->func_hash->filter_hash;
+
+	if (ftrace_hash_empty(hash))
+		hash = NULL;
+
+	__ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
+}
+
+static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
+				       struct ftrace_hash *new_hash)
+{
+	struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
+
+	if (ftrace_hash_empty(old_hash))
+		old_hash = NULL;
+
+	if (ftrace_hash_empty(new_hash))
+		new_hash = NULL;
+
+	return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
+}
+
+static void print_ip_ins(const char *fmt, const unsigned char *p)
+{
+	char ins[MCOUNT_INSN_SIZE];
+
+	if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
+		printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
+		return;
+	}
+
+	printk(KERN_CONT "%s", fmt);
+	pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
+}
+
+enum ftrace_bug_type ftrace_bug_type;
+const void *ftrace_expected;
+
+static void print_bug_type(void)
+{
+	switch (ftrace_bug_type) {
+	case FTRACE_BUG_UNKNOWN:
+		break;
+	case FTRACE_BUG_INIT:
+		pr_info("Initializing ftrace call sites\n");
+		break;
+	case FTRACE_BUG_NOP:
+		pr_info("Setting ftrace call site to NOP\n");
+		break;
+	case FTRACE_BUG_CALL:
+		pr_info("Setting ftrace call site to call ftrace function\n");
+		break;
+	case FTRACE_BUG_UPDATE:
+		pr_info("Updating ftrace call site to call a different ftrace function\n");
+		break;
+	}
+}
+
+/**
+ * ftrace_bug - report and shutdown function tracer
+ * @failed: The failed type (EFAULT, EINVAL, EPERM)
+ * @rec: The record that failed
+ *
+ * The arch code that enables or disables the function tracing
+ * can call ftrace_bug() when it has detected a problem in
+ * modifying the code. @failed should be one of either:
+ * EFAULT - if the problem happens on reading the @ip address
+ * EINVAL - if what is read at @ip is not what was expected
+ * EPERM - if the problem happens on writing to the @ip address
+ */
+void ftrace_bug(int failed, struct dyn_ftrace *rec)
+{
+	unsigned long ip = rec ? rec->ip : 0;
+
+	pr_info("------------[ ftrace bug ]------------\n");
+
+	switch (failed) {
+	case -EFAULT:
+		pr_info("ftrace faulted on modifying ");
+		print_ip_sym(KERN_INFO, ip);
+		break;
+	case -EINVAL:
+		pr_info("ftrace failed to modify ");
+		print_ip_sym(KERN_INFO, ip);
+		print_ip_ins(" actual:   ", (unsigned char *)ip);
+		pr_cont("\n");
+		if (ftrace_expected) {
+			print_ip_ins(" expected: ", ftrace_expected);
+			pr_cont("\n");
+		}
+		break;
+	case -EPERM:
+		pr_info("ftrace faulted on writing ");
+		print_ip_sym(KERN_INFO, ip);
+		break;
+	default:
+		pr_info("ftrace faulted on unknown error ");
+		print_ip_sym(KERN_INFO, ip);
+	}
+	print_bug_type();
+	if (rec) {
+		struct ftrace_ops *ops = NULL;
+
+		pr_info("ftrace record flags: %lx\n", rec->flags);
+		pr_cont(" (%ld)%s", ftrace_rec_count(rec),
+			rec->flags & FTRACE_FL_REGS ? " R" : "  ");
+		if (rec->flags & FTRACE_FL_TRAMP_EN) {
+			ops = ftrace_find_tramp_ops_any(rec);
+			if (ops) {
+				do {
+					pr_cont("\ttramp: %pS (%pS)",
+						(void *)ops->trampoline,
+						(void *)ops->func);
+					ops = ftrace_find_tramp_ops_next(rec, ops);
+				} while (ops);
+			} else
+				pr_cont("\ttramp: ERROR!");
+
+		}
+		ip = ftrace_get_addr_curr(rec);
+		pr_cont("\n expected tramp: %lx\n", ip);
+	}
+
+	FTRACE_WARN_ON_ONCE(1);
+}
+
+static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
+{
+	unsigned long flag = 0UL;
+
+	ftrace_bug_type = FTRACE_BUG_UNKNOWN;
+
+	if (skip_record(rec))
+		return FTRACE_UPDATE_IGNORE;
+
+	/*
+	 * If we are updating calls:
+	 *
+	 *   If the record has a ref count, then we need to enable it
+	 *   because someone is using it.
+	 *
+	 *   Otherwise we make sure its disabled.
+	 *
+	 * If we are disabling calls, then disable all records that
+	 * are enabled.
+	 */
+	if (enable && ftrace_rec_count(rec))
+		flag = FTRACE_FL_ENABLED;
+
+	/*
+	 * If enabling and the REGS flag does not match the REGS_EN, or
+	 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
+	 * this record. Set flags to fail the compare against ENABLED.
+	 * Same for direct calls.
+	 */
+	if (flag) {
+		if (!(rec->flags & FTRACE_FL_REGS) !=
+		    !(rec->flags & FTRACE_FL_REGS_EN))
+			flag |= FTRACE_FL_REGS;
+
+		if (!(rec->flags & FTRACE_FL_TRAMP) !=
+		    !(rec->flags & FTRACE_FL_TRAMP_EN))
+			flag |= FTRACE_FL_TRAMP;
+
+		/*
+		 * Direct calls are special, as count matters.
+		 * We must test the record for direct, if the
+		 * DIRECT and DIRECT_EN do not match, but only
+		 * if the count is 1. That's because, if the
+		 * count is something other than one, we do not
+		 * want the direct enabled (it will be done via the
+		 * direct helper). But if DIRECT_EN is set, and
+		 * the count is not one, we need to clear it.
+		 */
+		if (ftrace_rec_count(rec) == 1) {
+			if (!(rec->flags & FTRACE_FL_DIRECT) !=
+			    !(rec->flags & FTRACE_FL_DIRECT_EN))
+				flag |= FTRACE_FL_DIRECT;
+		} else if (rec->flags & FTRACE_FL_DIRECT_EN) {
+			flag |= FTRACE_FL_DIRECT;
+		}
+	}
+
+	/* If the state of this record hasn't changed, then do nothing */
+	if ((rec->flags & FTRACE_FL_ENABLED) == flag)
+		return FTRACE_UPDATE_IGNORE;
+
+	if (flag) {
+		/* Save off if rec is being enabled (for return value) */
+		flag ^= rec->flags & FTRACE_FL_ENABLED;
+
+		if (update) {
+			rec->flags |= FTRACE_FL_ENABLED;
+			if (flag & FTRACE_FL_REGS) {
+				if (rec->flags & FTRACE_FL_REGS)
+					rec->flags |= FTRACE_FL_REGS_EN;
+				else
+					rec->flags &= ~FTRACE_FL_REGS_EN;
+			}
+			if (flag & FTRACE_FL_TRAMP) {
+				if (rec->flags & FTRACE_FL_TRAMP)
+					rec->flags |= FTRACE_FL_TRAMP_EN;
+				else
+					rec->flags &= ~FTRACE_FL_TRAMP_EN;
+			}
+
+			if (flag & FTRACE_FL_DIRECT) {
+				/*
+				 * If there's only one user (direct_ops helper)
+				 * then we can call the direct function
+				 * directly (no ftrace trampoline).
+				 */
+				if (ftrace_rec_count(rec) == 1) {
+					if (rec->flags & FTRACE_FL_DIRECT)
+						rec->flags |= FTRACE_FL_DIRECT_EN;
+					else
+						rec->flags &= ~FTRACE_FL_DIRECT_EN;
+				} else {
+					/*
+					 * Can only call directly if there's
+					 * only one callback to the function.
+					 */
+					rec->flags &= ~FTRACE_FL_DIRECT_EN;
+				}
+			}
+		}
+
+		/*
+		 * If this record is being updated from a nop, then
+		 *   return UPDATE_MAKE_CALL.
+		 * Otherwise,
+		 *   return UPDATE_MODIFY_CALL to tell the caller to convert
+		 *   from the save regs, to a non-save regs function or
+		 *   vice versa, or from a trampoline call.
+		 */
+		if (flag & FTRACE_FL_ENABLED) {
+			ftrace_bug_type = FTRACE_BUG_CALL;
+			return FTRACE_UPDATE_MAKE_CALL;
+		}
+
+		ftrace_bug_type = FTRACE_BUG_UPDATE;
+		return FTRACE_UPDATE_MODIFY_CALL;
+	}
+
+	if (update) {
+		/* If there's no more users, clear all flags */
+		if (!ftrace_rec_count(rec))
+			rec->flags &= FTRACE_FL_DISABLED;
+		else
+			/*
+			 * Just disable the record, but keep the ops TRAMP
+			 * and REGS states. The _EN flags must be disabled though.
+			 */
+			rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
+					FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
+	}
+
+	ftrace_bug_type = FTRACE_BUG_NOP;
+	return FTRACE_UPDATE_MAKE_NOP;
+}
+
+/**
+ * ftrace_update_record - set a record that now is tracing or not
+ * @rec: the record to update
+ * @enable: set to true if the record is tracing, false to force disable
+ *
+ * The records that represent all functions that can be traced need
+ * to be updated when tracing has been enabled.
+ */
+int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
+{
+	return ftrace_check_record(rec, enable, true);
+}
+
+/**
+ * ftrace_test_record - check if the record has been enabled or not
+ * @rec: the record to test
+ * @enable: set to true to check if enabled, false if it is disabled
+ *
+ * The arch code may need to test if a record is already set to
+ * tracing to determine how to modify the function code that it
+ * represents.
+ */
+int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
+{
+	return ftrace_check_record(rec, enable, false);
+}
+
+static struct ftrace_ops *
+ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
+{
+	struct ftrace_ops *op;
+	unsigned long ip = rec->ip;
+
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+
+		if (!op->trampoline)
+			continue;
+
+		if (hash_contains_ip(ip, op->func_hash))
+			return op;
+	} while_for_each_ftrace_op(op);
+
+	return NULL;
+}
+
+static struct ftrace_ops *
+ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
+{
+	struct ftrace_ops *op;
+	unsigned long ip = rec->ip;
+
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+
+		if (op == op_exclude || !op->trampoline)
+			continue;
+
+		if (hash_contains_ip(ip, op->func_hash))
+			return op;
+	} while_for_each_ftrace_op(op);
+
+	return NULL;
+}
+
+static struct ftrace_ops *
+ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
+			   struct ftrace_ops *op)
+{
+	unsigned long ip = rec->ip;
+
+	while_for_each_ftrace_op(op) {
+
+		if (!op->trampoline)
+			continue;
+
+		if (hash_contains_ip(ip, op->func_hash))
+			return op;
+	}
+
+	return NULL;
+}
+
+static struct ftrace_ops *
+ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
+{
+	struct ftrace_ops *op;
+	unsigned long ip = rec->ip;
+
+	/*
+	 * Need to check removed ops first.
+	 * If they are being removed, and this rec has a tramp,
+	 * and this rec is in the ops list, then it would be the
+	 * one with the tramp.
+	 */
+	if (removed_ops) {
+		if (hash_contains_ip(ip, &removed_ops->old_hash))
+			return removed_ops;
+	}
+
+	/*
+	 * Need to find the current trampoline for a rec.
+	 * Now, a trampoline is only attached to a rec if there
+	 * was a single 'ops' attached to it. But this can be called
+	 * when we are adding another op to the rec or removing the
+	 * current one. Thus, if the op is being added, we can
+	 * ignore it because it hasn't attached itself to the rec
+	 * yet.
+	 *
+	 * If an ops is being modified (hooking to different functions)
+	 * then we don't care about the new functions that are being
+	 * added, just the old ones (that are probably being removed).
+	 *
+	 * If we are adding an ops to a function that already is using
+	 * a trampoline, it needs to be removed (trampolines are only
+	 * for single ops connected), then an ops that is not being
+	 * modified also needs to be checked.
+	 */
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+
+		if (!op->trampoline)
+			continue;
+
+		/*
+		 * If the ops is being added, it hasn't gotten to
+		 * the point to be removed from this tree yet.
+		 */
+		if (op->flags & FTRACE_OPS_FL_ADDING)
+			continue;
+
+
+		/*
+		 * If the ops is being modified and is in the old
+		 * hash, then it is probably being removed from this
+		 * function.
+		 */
+		if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
+		    hash_contains_ip(ip, &op->old_hash))
+			return op;
+		/*
+		 * If the ops is not being added or modified, and it's
+		 * in its normal filter hash, then this must be the one
+		 * we want!
+		 */
+		if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
+		    hash_contains_ip(ip, op->func_hash))
+			return op;
+
+	} while_for_each_ftrace_op(op);
+
+	return NULL;
+}
+
+static struct ftrace_ops *
+ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
+{
+	struct ftrace_ops *op;
+	unsigned long ip = rec->ip;
+
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		/* pass rec in as regs to have non-NULL val */
+		if (hash_contains_ip(ip, op->func_hash))
+			return op;
+	} while_for_each_ftrace_op(op);
+
+	return NULL;
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+/* Protected by rcu_tasks for reading, and direct_mutex for writing */
+static struct ftrace_hash *direct_functions = EMPTY_HASH;
+static DEFINE_MUTEX(direct_mutex);
+int ftrace_direct_func_count;
+
+/*
+ * Search the direct_functions hash to see if the given instruction pointer
+ * has a direct caller attached to it.
+ */
+unsigned long ftrace_find_rec_direct(unsigned long ip)
+{
+	struct ftrace_func_entry *entry;
+
+	entry = __ftrace_lookup_ip(direct_functions, ip);
+	if (!entry)
+		return 0;
+
+	return entry->direct;
+}
+
+static struct ftrace_func_entry*
+ftrace_add_rec_direct(unsigned long ip, unsigned long addr,
+		      struct ftrace_hash **free_hash)
+{
+	struct ftrace_func_entry *entry;
+
+	if (ftrace_hash_empty(direct_functions) ||
+	    direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
+		struct ftrace_hash *new_hash;
+		int size = ftrace_hash_empty(direct_functions) ? 0 :
+			direct_functions->count + 1;
+
+		if (size < 32)
+			size = 32;
+
+		new_hash = dup_hash(direct_functions, size);
+		if (!new_hash)
+			return NULL;
+
+		*free_hash = direct_functions;
+		direct_functions = new_hash;
+	}
+
+	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return NULL;
+
+	entry->ip = ip;
+	entry->direct = addr;
+	__add_hash_entry(direct_functions, entry);
+	return entry;
+}
+
+static void call_direct_funcs(unsigned long ip, unsigned long pip,
+			      struct ftrace_ops *ops, struct ftrace_regs *fregs)
+{
+	struct pt_regs *regs = ftrace_get_regs(fregs);
+	unsigned long addr;
+
+	addr = ftrace_find_rec_direct(ip);
+	if (!addr)
+		return;
+
+	arch_ftrace_set_direct_caller(regs, addr);
+}
+
+struct ftrace_ops direct_ops = {
+	.func		= call_direct_funcs,
+	.flags		= FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
+			  | FTRACE_OPS_FL_PERMANENT,
+	/*
+	 * By declaring the main trampoline as this trampoline
+	 * it will never have one allocated for it. Allocated
+	 * trampolines should not call direct functions.
+	 * The direct_ops should only be called by the builtin
+	 * ftrace_regs_caller trampoline.
+	 */
+	.trampoline	= FTRACE_REGS_ADDR,
+};
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
+
+/**
+ * ftrace_get_addr_new - Get the call address to set to
+ * @rec:  The ftrace record descriptor
+ *
+ * If the record has the FTRACE_FL_REGS set, that means that it
+ * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
+ * is not set, then it wants to convert to the normal callback.
+ *
+ * Returns the address of the trampoline to set to
+ */
+unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
+{
+	struct ftrace_ops *ops;
+	unsigned long addr;
+
+	if ((rec->flags & FTRACE_FL_DIRECT) &&
+	    (ftrace_rec_count(rec) == 1)) {
+		addr = ftrace_find_rec_direct(rec->ip);
+		if (addr)
+			return addr;
+		WARN_ON_ONCE(1);
+	}
+
+	/* Trampolines take precedence over regs */
+	if (rec->flags & FTRACE_FL_TRAMP) {
+		ops = ftrace_find_tramp_ops_new(rec);
+		if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
+			pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
+				(void *)rec->ip, (void *)rec->ip, rec->flags);
+			/* Ftrace is shutting down, return anything */
+			return (unsigned long)FTRACE_ADDR;
+		}
+		return ops->trampoline;
+	}
+
+	if (rec->flags & FTRACE_FL_REGS)
+		return (unsigned long)FTRACE_REGS_ADDR;
+	else
+		return (unsigned long)FTRACE_ADDR;
+}
+
+/**
+ * ftrace_get_addr_curr - Get the call address that is already there
+ * @rec:  The ftrace record descriptor
+ *
+ * The FTRACE_FL_REGS_EN is set when the record already points to
+ * a function that saves all the regs. Basically the '_EN' version
+ * represents the current state of the function.
+ *
+ * Returns the address of the trampoline that is currently being called
+ */
+unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
+{
+	struct ftrace_ops *ops;
+	unsigned long addr;
+
+	/* Direct calls take precedence over trampolines */
+	if (rec->flags & FTRACE_FL_DIRECT_EN) {
+		addr = ftrace_find_rec_direct(rec->ip);
+		if (addr)
+			return addr;
+		WARN_ON_ONCE(1);
+	}
+
+	/* Trampolines take precedence over regs */
+	if (rec->flags & FTRACE_FL_TRAMP_EN) {
+		ops = ftrace_find_tramp_ops_curr(rec);
+		if (FTRACE_WARN_ON(!ops)) {
+			pr_warn("Bad trampoline accounting at: %p (%pS)\n",
+				(void *)rec->ip, (void *)rec->ip);
+			/* Ftrace is shutting down, return anything */
+			return (unsigned long)FTRACE_ADDR;
+		}
+		return ops->trampoline;
+	}
+
+	if (rec->flags & FTRACE_FL_REGS_EN)
+		return (unsigned long)FTRACE_REGS_ADDR;
+	else
+		return (unsigned long)FTRACE_ADDR;
+}
+
+static int
+__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
+{
+	unsigned long ftrace_old_addr;
+	unsigned long ftrace_addr;
+	int ret;
+
+	ftrace_addr = ftrace_get_addr_new(rec);
+
+	/* This needs to be done before we call ftrace_update_record */
+	ftrace_old_addr = ftrace_get_addr_curr(rec);
+
+	ret = ftrace_update_record(rec, enable);
+
+	ftrace_bug_type = FTRACE_BUG_UNKNOWN;
+
+	switch (ret) {
+	case FTRACE_UPDATE_IGNORE:
+		return 0;
+
+	case FTRACE_UPDATE_MAKE_CALL:
+		ftrace_bug_type = FTRACE_BUG_CALL;
+		return ftrace_make_call(rec, ftrace_addr);
+
+	case FTRACE_UPDATE_MAKE_NOP:
+		ftrace_bug_type = FTRACE_BUG_NOP;
+		return ftrace_make_nop(NULL, rec, ftrace_old_addr);
+
+	case FTRACE_UPDATE_MODIFY_CALL:
+		ftrace_bug_type = FTRACE_BUG_UPDATE;
+		return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
+	}
+
+	return -1; /* unknown ftrace bug */
+}
+
+void __weak ftrace_replace_code(int mod_flags)
+{
+	struct dyn_ftrace *rec;
+	struct ftrace_page *pg;
+	bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
+	int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
+	int failed;
+
+	if (unlikely(ftrace_disabled))
+		return;
+
+	do_for_each_ftrace_rec(pg, rec) {
+
+		if (skip_record(rec))
+			continue;
+
+		failed = __ftrace_replace_code(rec, enable);
+		if (failed) {
+			ftrace_bug(failed, rec);
+			/* Stop processing */
+			return;
+		}
+		if (schedulable)
+			cond_resched();
+	} while_for_each_ftrace_rec();
+}
+
+struct ftrace_rec_iter {
+	struct ftrace_page	*pg;
+	int			index;
+};
+
+/**
+ * ftrace_rec_iter_start - start up iterating over traced functions
+ *
+ * Returns an iterator handle that is used to iterate over all
+ * the records that represent address locations where functions
+ * are traced.
+ *
+ * May return NULL if no records are available.
+ */
+struct ftrace_rec_iter *ftrace_rec_iter_start(void)
+{
+	/*
+	 * We only use a single iterator.
+	 * Protected by the ftrace_lock mutex.
+	 */
+	static struct ftrace_rec_iter ftrace_rec_iter;
+	struct ftrace_rec_iter *iter = &ftrace_rec_iter;
+
+	iter->pg = ftrace_pages_start;
+	iter->index = 0;
+
+	/* Could have empty pages */
+	while (iter->pg && !iter->pg->index)
+		iter->pg = iter->pg->next;
+
+	if (!iter->pg)
+		return NULL;
+
+	return iter;
+}
+
+/**
+ * ftrace_rec_iter_next - get the next record to process.
+ * @iter: The handle to the iterator.
+ *
+ * Returns the next iterator after the given iterator @iter.
+ */
+struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
+{
+	iter->index++;
+
+	if (iter->index >= iter->pg->index) {
+		iter->pg = iter->pg->next;
+		iter->index = 0;
+
+		/* Could have empty pages */
+		while (iter->pg && !iter->pg->index)
+			iter->pg = iter->pg->next;
+	}
+
+	if (!iter->pg)
+		return NULL;
+
+	return iter;
+}
+
+/**
+ * ftrace_rec_iter_record - get the record at the iterator location
+ * @iter: The current iterator location
+ *
+ * Returns the record that the current @iter is at.
+ */
+struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
+{
+	return &iter->pg->records[iter->index];
+}
+
+static int
+ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
+{
+	int ret;
+
+	if (unlikely(ftrace_disabled))
+		return 0;
+
+	ret = ftrace_init_nop(mod, rec);
+	if (ret) {
+		ftrace_bug_type = FTRACE_BUG_INIT;
+		ftrace_bug(ret, rec);
+		return 0;
+	}
+	return 1;
+}
+
+/*
+ * archs can override this function if they must do something
+ * before the modifying code is performed.
+ */
+void __weak ftrace_arch_code_modify_prepare(void)
+{
+}
+
+/*
+ * archs can override this function if they must do something
+ * after the modifying code is performed.
+ */
+void __weak ftrace_arch_code_modify_post_process(void)
+{
+}
+
+void ftrace_modify_all_code(int command)
+{
+	int update = command & FTRACE_UPDATE_TRACE_FUNC;
+	int mod_flags = 0;
+	int err = 0;
+
+	if (command & FTRACE_MAY_SLEEP)
+		mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
+
+	/*
+	 * If the ftrace_caller calls a ftrace_ops func directly,
+	 * we need to make sure that it only traces functions it
+	 * expects to trace. When doing the switch of functions,
+	 * we need to update to the ftrace_ops_list_func first
+	 * before the transition between old and new calls are set,
+	 * as the ftrace_ops_list_func will check the ops hashes
+	 * to make sure the ops are having the right functions
+	 * traced.
+	 */
+	if (update) {
+		err = ftrace_update_ftrace_func(ftrace_ops_list_func);
+		if (FTRACE_WARN_ON(err))
+			return;
+	}
+
+	if (command & FTRACE_UPDATE_CALLS)
+		ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
+	else if (command & FTRACE_DISABLE_CALLS)
+		ftrace_replace_code(mod_flags);
+
+	if (update && ftrace_trace_function != ftrace_ops_list_func) {
+		function_trace_op = set_function_trace_op;
+		smp_wmb();
+		/* If irqs are disabled, we are in stop machine */
+		if (!irqs_disabled())
+			smp_call_function(ftrace_sync_ipi, NULL, 1);
+		err = ftrace_update_ftrace_func(ftrace_trace_function);
+		if (FTRACE_WARN_ON(err))
+			return;
+	}
+
+	if (command & FTRACE_START_FUNC_RET)
+		err = ftrace_enable_ftrace_graph_caller();
+	else if (command & FTRACE_STOP_FUNC_RET)
+		err = ftrace_disable_ftrace_graph_caller();
+	FTRACE_WARN_ON(err);
+}
+
+static int __ftrace_modify_code(void *data)
+{
+	int *command = data;
+
+	ftrace_modify_all_code(*command);
+
+	return 0;
+}
+
+/**
+ * ftrace_run_stop_machine - go back to the stop machine method
+ * @command: The command to tell ftrace what to do
+ *
+ * If an arch needs to fall back to the stop machine method, the
+ * it can call this function.
+ */
+void ftrace_run_stop_machine(int command)
+{
+	stop_machine(__ftrace_modify_code, &command, NULL);
+}
+
+/**
+ * arch_ftrace_update_code - modify the code to trace or not trace
+ * @command: The command that needs to be done
+ *
+ * Archs can override this function if it does not need to
+ * run stop_machine() to modify code.
+ */
+void __weak arch_ftrace_update_code(int command)
+{
+	ftrace_run_stop_machine(command);
+}
+
+static void ftrace_run_update_code(int command)
+{
+	ftrace_arch_code_modify_prepare();
+
+	/*
+	 * By default we use stop_machine() to modify the code.
+	 * But archs can do what ever they want as long as it
+	 * is safe. The stop_machine() is the safest, but also
+	 * produces the most overhead.
+	 */
+	arch_ftrace_update_code(command);
+
+	ftrace_arch_code_modify_post_process();
+}
+
+static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
+				   struct ftrace_ops_hash *old_hash)
+{
+	ops->flags |= FTRACE_OPS_FL_MODIFYING;
+	ops->old_hash.filter_hash = old_hash->filter_hash;
+	ops->old_hash.notrace_hash = old_hash->notrace_hash;
+	ftrace_run_update_code(command);
+	ops->old_hash.filter_hash = NULL;
+	ops->old_hash.notrace_hash = NULL;
+	ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
+}
+
+static ftrace_func_t saved_ftrace_func;
+static int ftrace_start_up;
+
+void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
+{
+}
+
+/* List of trace_ops that have allocated trampolines */
+static LIST_HEAD(ftrace_ops_trampoline_list);
+
+static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
+{
+	lockdep_assert_held(&ftrace_lock);
+	list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
+}
+
+static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
+{
+	lockdep_assert_held(&ftrace_lock);
+	list_del_rcu(&ops->list);
+	synchronize_rcu();
+}
+
+/*
+ * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
+ * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
+ * not a module.
+ */
+#define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
+#define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
+
+static void ftrace_trampoline_free(struct ftrace_ops *ops)
+{
+	if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
+	    ops->trampoline) {
+		/*
+		 * Record the text poke event before the ksymbol unregister
+		 * event.
+		 */
+		perf_event_text_poke((void *)ops->trampoline,
+				     (void *)ops->trampoline,
+				     ops->trampoline_size, NULL, 0);
+		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
+				   ops->trampoline, ops->trampoline_size,
+				   true, FTRACE_TRAMPOLINE_SYM);
+		/* Remove from kallsyms after the perf events */
+		ftrace_remove_trampoline_from_kallsyms(ops);
+	}
+
+	arch_ftrace_trampoline_free(ops);
+}
+
+static void ftrace_startup_enable(int command)
+{
+	if (saved_ftrace_func != ftrace_trace_function) {
+		saved_ftrace_func = ftrace_trace_function;
+		command |= FTRACE_UPDATE_TRACE_FUNC;
+	}
+
+	if (!command || !ftrace_enabled)
+		return;
+
+	ftrace_run_update_code(command);
+}
+
+static void ftrace_startup_all(int command)
+{
+	update_all_ops = true;
+	ftrace_startup_enable(command);
+	update_all_ops = false;
+}
+
+int ftrace_startup(struct ftrace_ops *ops, int command)
+{
+	int ret;
+
+	if (unlikely(ftrace_disabled))
+		return -ENODEV;
+
+	ret = __register_ftrace_function(ops);
+	if (ret)
+		return ret;
+
+	ftrace_start_up++;
+
+	/*
+	 * Note that ftrace probes uses this to start up
+	 * and modify functions it will probe. But we still
+	 * set the ADDING flag for modification, as probes
+	 * do not have trampolines. If they add them in the
+	 * future, then the probes will need to distinguish
+	 * between adding and updating probes.
+	 */
+	ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
+
+	ret = ftrace_hash_ipmodify_enable(ops);
+	if (ret < 0) {
+		/* Rollback registration process */
+		__unregister_ftrace_function(ops);
+		ftrace_start_up--;
+		ops->flags &= ~FTRACE_OPS_FL_ENABLED;
+		if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
+			ftrace_trampoline_free(ops);
+		return ret;
+	}
+
+	if (ftrace_hash_rec_enable(ops, 1))
+		command |= FTRACE_UPDATE_CALLS;
+
+	ftrace_startup_enable(command);
+
+	/*
+	 * If ftrace is in an undefined state, we just remove ops from list
+	 * to prevent the NULL pointer, instead of totally rolling it back and
+	 * free trampoline, because those actions could cause further damage.
+	 */
+	if (unlikely(ftrace_disabled)) {
+		__unregister_ftrace_function(ops);
+		return -ENODEV;
+	}
+
+	ops->flags &= ~FTRACE_OPS_FL_ADDING;
+
+	return 0;
+}
+
+int ftrace_shutdown(struct ftrace_ops *ops, int command)
+{
+	int ret;
+
+	if (unlikely(ftrace_disabled))
+		return -ENODEV;
+
+	ret = __unregister_ftrace_function(ops);
+	if (ret)
+		return ret;
+
+	ftrace_start_up--;
+	/*
+	 * Just warn in case of unbalance, no need to kill ftrace, it's not
+	 * critical but the ftrace_call callers may be never nopped again after
+	 * further ftrace uses.
+	 */
+	WARN_ON_ONCE(ftrace_start_up < 0);
+
+	/* Disabling ipmodify never fails */
+	ftrace_hash_ipmodify_disable(ops);
+
+	if (ftrace_hash_rec_disable(ops, 1))
+		command |= FTRACE_UPDATE_CALLS;
+
+	ops->flags &= ~FTRACE_OPS_FL_ENABLED;
+
+	if (saved_ftrace_func != ftrace_trace_function) {
+		saved_ftrace_func = ftrace_trace_function;
+		command |= FTRACE_UPDATE_TRACE_FUNC;
+	}
+
+	if (!command || !ftrace_enabled)
+		goto out;
+
+	/*
+	 * If the ops uses a trampoline, then it needs to be
+	 * tested first on update.
+	 */
+	ops->flags |= FTRACE_OPS_FL_REMOVING;
+	removed_ops = ops;
+
+	/* The trampoline logic checks the old hashes */
+	ops->old_hash.filter_hash = ops->func_hash->filter_hash;
+	ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
+
+	ftrace_run_update_code(command);
+
+	/*
+	 * If there's no more ops registered with ftrace, run a
+	 * sanity check to make sure all rec flags are cleared.
+	 */
+	if (rcu_dereference_protected(ftrace_ops_list,
+			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
+		struct ftrace_page *pg;
+		struct dyn_ftrace *rec;
+
+		do_for_each_ftrace_rec(pg, rec) {
+			if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
+				pr_warn("  %pS flags:%lx\n",
+					(void *)rec->ip, rec->flags);
+		} while_for_each_ftrace_rec();
+	}
+
+	ops->old_hash.filter_hash = NULL;
+	ops->old_hash.notrace_hash = NULL;
+
+	removed_ops = NULL;
+	ops->flags &= ~FTRACE_OPS_FL_REMOVING;
+
+out:
+	/*
+	 * Dynamic ops may be freed, we must make sure that all
+	 * callers are done before leaving this function.
+	 * The same goes for freeing the per_cpu data of the per_cpu
+	 * ops.
+	 */
+	if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
+		/*
+		 * We need to do a hard force of sched synchronization.
+		 * This is because we use preempt_disable() to do RCU, but
+		 * the function tracers can be called where RCU is not watching
+		 * (like before user_exit()). We can not rely on the RCU
+		 * infrastructure to do the synchronization, thus we must do it
+		 * ourselves.
+		 */
+		synchronize_rcu_tasks_rude();
+
+		/*
+		 * When the kernel is preemptive, tasks can be preempted
+		 * while on a ftrace trampoline. Just scheduling a task on
+		 * a CPU is not good enough to flush them. Calling
+		 * synchronize_rcu_tasks() will wait for those tasks to
+		 * execute and either schedule voluntarily or enter user space.
+		 */
+		if (IS_ENABLED(CONFIG_PREEMPTION))
+			synchronize_rcu_tasks();
+
+		ftrace_trampoline_free(ops);
+	}
+
+	return 0;
+}
+
+static u64		ftrace_update_time;
+unsigned long		ftrace_update_tot_cnt;
+unsigned long		ftrace_number_of_pages;
+unsigned long		ftrace_number_of_groups;
+
+static inline int ops_traces_mod(struct ftrace_ops *ops)
+{
+	/*
+	 * Filter_hash being empty will default to trace module.
+	 * But notrace hash requires a test of individual module functions.
+	 */
+	return ftrace_hash_empty(ops->func_hash->filter_hash) &&
+		ftrace_hash_empty(ops->func_hash->notrace_hash);
+}
+
+static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
+{
+	bool init_nop = ftrace_need_init_nop();
+	struct ftrace_page *pg;
+	struct dyn_ftrace *p;
+	u64 start, stop;
+	unsigned long update_cnt = 0;
+	unsigned long rec_flags = 0;
+	int i;
+
+	start = ftrace_now(raw_smp_processor_id());
+
+	/*
+	 * When a module is loaded, this function is called to convert
+	 * the calls to mcount in its text to nops, and also to create
+	 * an entry in the ftrace data. Now, if ftrace is activated
+	 * after this call, but before the module sets its text to
+	 * read-only, the modification of enabling ftrace can fail if
+	 * the read-only is done while ftrace is converting the calls.
+	 * To prevent this, the module's records are set as disabled
+	 * and will be enabled after the call to set the module's text
+	 * to read-only.
+	 */
+	if (mod)
+		rec_flags |= FTRACE_FL_DISABLED;
+
+	for (pg = new_pgs; pg; pg = pg->next) {
+
+		for (i = 0; i < pg->index; i++) {
+
+			/* If something went wrong, bail without enabling anything */
+			if (unlikely(ftrace_disabled))
+				return -1;
+
+			p = &pg->records[i];
+			p->flags = rec_flags;
+
+			/*
+			 * Do the initial record conversion from mcount jump
+			 * to the NOP instructions.
+			 */
+			if (init_nop && !ftrace_nop_initialize(mod, p))
+				break;
+
+			update_cnt++;
+		}
+	}
+
+	stop = ftrace_now(raw_smp_processor_id());
+	ftrace_update_time = stop - start;
+	ftrace_update_tot_cnt += update_cnt;
+
+	return 0;
+}
+
+static int ftrace_allocate_records(struct ftrace_page *pg, int count)
+{
+	int order;
+	int pages;
+	int cnt;
+
+	if (WARN_ON(!count))
+		return -EINVAL;
+
+	/* We want to fill as much as possible, with no empty pages */
+	pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
+	order = fls(pages) - 1;
+
+ again:
+	pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
+
+	if (!pg->records) {
+		/* if we can't allocate this size, try something smaller */
+		if (!order)
+			return -ENOMEM;
+		order--;
+		goto again;
+	}
+
+	ftrace_number_of_pages += 1 << order;
+	ftrace_number_of_groups++;
+
+	cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
+	pg->order = order;
+
+	if (cnt > count)
+		cnt = count;
+
+	return cnt;
+}
+
+static void ftrace_free_pages(struct ftrace_page *pages)
+{
+	struct ftrace_page *pg = pages;
+
+	while (pg) {
+		if (pg->records) {
+			free_pages((unsigned long)pg->records, pg->order);
+			ftrace_number_of_pages -= 1 << pg->order;
+		}
+		pages = pg->next;
+		kfree(pg);
+		pg = pages;
+		ftrace_number_of_groups--;
+	}
+}
+
+static struct ftrace_page *
+ftrace_allocate_pages(unsigned long num_to_init)
+{
+	struct ftrace_page *start_pg;
+	struct ftrace_page *pg;
+	int cnt;
+
+	if (!num_to_init)
+		return NULL;
+
+	start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
+	if (!pg)
+		return NULL;
+
+	/*
+	 * Try to allocate as much as possible in one continues
+	 * location that fills in all of the space. We want to
+	 * waste as little space as possible.
+	 */
+	for (;;) {
+		cnt = ftrace_allocate_records(pg, num_to_init);
+		if (cnt < 0)
+			goto free_pages;
+
+		num_to_init -= cnt;
+		if (!num_to_init)
+			break;
+
+		pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
+		if (!pg->next)
+			goto free_pages;
+
+		pg = pg->next;
+	}
+
+	return start_pg;
+
+ free_pages:
+	ftrace_free_pages(start_pg);
+	pr_info("ftrace: FAILED to allocate memory for functions\n");
+	return NULL;
+}
+
+#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
+
+struct ftrace_iterator {
+	loff_t				pos;
+	loff_t				func_pos;
+	loff_t				mod_pos;
+	struct ftrace_page		*pg;
+	struct dyn_ftrace		*func;
+	struct ftrace_func_probe	*probe;
+	struct ftrace_func_entry	*probe_entry;
+	struct trace_parser		parser;
+	struct ftrace_hash		*hash;
+	struct ftrace_ops		*ops;
+	struct trace_array		*tr;
+	struct list_head		*mod_list;
+	int				pidx;
+	int				idx;
+	unsigned			flags;
+};
+
+static void *
+t_probe_next(struct seq_file *m, loff_t *pos)
+{
+	struct ftrace_iterator *iter = m->private;
+	struct trace_array *tr = iter->ops->private;
+	struct list_head *func_probes;
+	struct ftrace_hash *hash;
+	struct list_head *next;
+	struct hlist_node *hnd = NULL;
+	struct hlist_head *hhd;
+	int size;
+
+	(*pos)++;
+	iter->pos = *pos;
+
+	if (!tr)
+		return NULL;
+
+	func_probes = &tr->func_probes;
+	if (list_empty(func_probes))
+		return NULL;
+
+	if (!iter->probe) {
+		next = func_probes->next;
+		iter->probe = list_entry(next, struct ftrace_func_probe, list);
+	}
+
+	if (iter->probe_entry)
+		hnd = &iter->probe_entry->hlist;
+
+	hash = iter->probe->ops.func_hash->filter_hash;
+
+	/*
+	 * A probe being registered may temporarily have an empty hash
+	 * and it's at the end of the func_probes list.
+	 */
+	if (!hash || hash == EMPTY_HASH)
+		return NULL;
+
+	size = 1 << hash->size_bits;
+
+ retry:
+	if (iter->pidx >= size) {
+		if (iter->probe->list.next == func_probes)
+			return NULL;
+		next = iter->probe->list.next;
+		iter->probe = list_entry(next, struct ftrace_func_probe, list);
+		hash = iter->probe->ops.func_hash->filter_hash;
+		size = 1 << hash->size_bits;
+		iter->pidx = 0;
+	}
+
+	hhd = &hash->buckets[iter->pidx];
+
+	if (hlist_empty(hhd)) {
+		iter->pidx++;
+		hnd = NULL;
+		goto retry;
+	}
+
+	if (!hnd)
+		hnd = hhd->first;
+	else {
+		hnd = hnd->next;
+		if (!hnd) {
+			iter->pidx++;
+			goto retry;
+		}
+	}
+
+	if (WARN_ON_ONCE(!hnd))
+		return NULL;
+
+	iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
+
+	return iter;
+}
+
+static void *t_probe_start(struct seq_file *m, loff_t *pos)
+{
+	struct ftrace_iterator *iter = m->private;
+	void *p = NULL;
+	loff_t l;
+
+	if (!(iter->flags & FTRACE_ITER_DO_PROBES))
+		return NULL;
+
+	if (iter->mod_pos > *pos)
+		return NULL;
+
+	iter->probe = NULL;
+	iter->probe_entry = NULL;
+	iter->pidx = 0;
+	for (l = 0; l <= (*pos - iter->mod_pos); ) {
+		p = t_probe_next(m, &l);
+		if (!p)
+			break;
+	}
+	if (!p)
+		return NULL;
+
+	/* Only set this if we have an item */
+	iter->flags |= FTRACE_ITER_PROBE;
+
+	return iter;
+}
+
+static int
+t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
+{
+	struct ftrace_func_entry *probe_entry;
+	struct ftrace_probe_ops *probe_ops;
+	struct ftrace_func_probe *probe;
+
+	probe = iter->probe;
+	probe_entry = iter->probe_entry;
+
+	if (WARN_ON_ONCE(!probe || !probe_entry))
+		return -EIO;
+
+	probe_ops = probe->probe_ops;
+
+	if (probe_ops->print)
+		return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
+
+	seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
+		   (void *)probe_ops->func);
+
+	return 0;
+}
+
+static void *
+t_mod_next(struct seq_file *m, loff_t *pos)
+{
+	struct ftrace_iterator *iter = m->private;
+	struct trace_array *tr = iter->tr;
+
+	(*pos)++;
+	iter->pos = *pos;
+
+	iter->mod_list = iter->mod_list->next;
+
+	if (iter->mod_list == &tr->mod_trace ||
+	    iter->mod_list == &tr->mod_notrace) {
+		iter->flags &= ~FTRACE_ITER_MOD;
+		return NULL;
+	}
+
+	iter->mod_pos = *pos;
+
+	return iter;
+}
+
+static void *t_mod_start(struct seq_file *m, loff_t *pos)
+{
+	struct ftrace_iterator *iter = m->private;
+	void *p = NULL;
+	loff_t l;
+
+	if (iter->func_pos > *pos)
+		return NULL;
+
+	iter->mod_pos = iter->func_pos;
+
+	/* probes are only available if tr is set */
+	if (!iter->tr)
+		return NULL;
+
+	for (l = 0; l <= (*pos - iter->func_pos); ) {
+		p = t_mod_next(m, &l);
+		if (!p)
+			break;
+	}
+	if (!p) {
+		iter->flags &= ~FTRACE_ITER_MOD;
+		return t_probe_start(m, pos);
+	}
+
+	/* Only set this if we have an item */
+	iter->flags |= FTRACE_ITER_MOD;
+
+	return iter;
+}
+
+static int
+t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
+{
+	struct ftrace_mod_load *ftrace_mod;
+	struct trace_array *tr = iter->tr;
+
+	if (WARN_ON_ONCE(!iter->mod_list) ||
+			 iter->mod_list == &tr->mod_trace ||
+			 iter->mod_list == &tr->mod_notrace)
+		return -EIO;
+
+	ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
+
+	if (ftrace_mod->func)
+		seq_printf(m, "%s", ftrace_mod->func);
+	else
+		seq_putc(m, '*');
+
+	seq_printf(m, ":mod:%s\n", ftrace_mod->module);
+
+	return 0;
+}
+
+static void *
+t_func_next(struct seq_file *m, loff_t *pos)
+{
+	struct ftrace_iterator *iter = m->private;
+	struct dyn_ftrace *rec = NULL;
+
+	(*pos)++;
+
+ retry:
+	if (iter->idx >= iter->pg->index) {
+		if (iter->pg->next) {
+			iter->pg = iter->pg->next;
+			iter->idx = 0;
+			goto retry;
+		}
+	} else {
+		rec = &iter->pg->records[iter->idx++];
+		if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
+		     !ftrace_lookup_ip(iter->hash, rec->ip)) ||
+
+		    ((iter->flags & FTRACE_ITER_ENABLED) &&
+		     !(rec->flags & FTRACE_FL_ENABLED))) {
+
+			rec = NULL;
+			goto retry;
+		}
+	}
+
+	if (!rec)
+		return NULL;
+
+	iter->pos = iter->func_pos = *pos;
+	iter->func = rec;
+
+	return iter;
+}
+
+static void *
+t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct ftrace_iterator *iter = m->private;
+	loff_t l = *pos; /* t_probe_start() must use original pos */
+	void *ret;
+
+	if (unlikely(ftrace_disabled))
+		return NULL;
+
+	if (iter->flags & FTRACE_ITER_PROBE)
+		return t_probe_next(m, pos);
+
+	if (iter->flags & FTRACE_ITER_MOD)
+		return t_mod_next(m, pos);
+
+	if (iter->flags & FTRACE_ITER_PRINTALL) {
+		/* next must increment pos, and t_probe_start does not */
+		(*pos)++;
+		return t_mod_start(m, &l);
+	}
+
+	ret = t_func_next(m, pos);
+
+	if (!ret)
+		return t_mod_start(m, &l);
+
+	return ret;
+}
+
+static void reset_iter_read(struct ftrace_iterator *iter)
+{
+	iter->pos = 0;
+	iter->func_pos = 0;
+	iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
+}
+
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+	struct ftrace_iterator *iter = m->private;
+	void *p = NULL;
+	loff_t l;
+
+	mutex_lock(&ftrace_lock);
+
+	if (unlikely(ftrace_disabled))
+		return NULL;
+
+	/*
+	 * If an lseek was done, then reset and start from beginning.
+	 */
+	if (*pos < iter->pos)
+		reset_iter_read(iter);
+
+	/*
+	 * For set_ftrace_filter reading, if we have the filter
+	 * off, we can short cut and just print out that all
+	 * functions are enabled.
+	 */
+	if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
+	    ftrace_hash_empty(iter->hash)) {
+		iter->func_pos = 1; /* Account for the message */
+		if (*pos > 0)
+			return t_mod_start(m, pos);
+		iter->flags |= FTRACE_ITER_PRINTALL;
+		/* reset in case of seek/pread */
+		iter->flags &= ~FTRACE_ITER_PROBE;
+		return iter;
+	}
+
+	if (iter->flags & FTRACE_ITER_MOD)
+		return t_mod_start(m, pos);
+
+	/*
+	 * Unfortunately, we need to restart at ftrace_pages_start
+	 * every time we let go of the ftrace_mutex. This is because
+	 * those pointers can change without the lock.
+	 */
+	iter->pg = ftrace_pages_start;
+	iter->idx = 0;
+	for (l = 0; l <= *pos; ) {
+		p = t_func_next(m, &l);
+		if (!p)
+			break;
+	}
+
+	if (!p)
+		return t_mod_start(m, pos);
+
+	return iter;
+}
+
+static void t_stop(struct seq_file *m, void *p)
+{
+	mutex_unlock(&ftrace_lock);
+}
+
+void * __weak
+arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
+{
+	return NULL;
+}
+
+static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
+				struct dyn_ftrace *rec)
+{
+	void *ptr;
+
+	ptr = arch_ftrace_trampoline_func(ops, rec);
+	if (ptr)
+		seq_printf(m, " ->%pS", ptr);
+}
+
+#ifdef FTRACE_MCOUNT_MAX_OFFSET
+/*
+ * Weak functions can still have an mcount/fentry that is saved in
+ * the __mcount_loc section. These can be detected by having a
+ * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
+ * symbol found by kallsyms is not the function that the mcount/fentry
+ * is part of. The offset is much greater in these cases.
+ *
+ * Test the record to make sure that the ip points to a valid kallsyms
+ * and if not, mark it disabled.
+ */
+static int test_for_valid_rec(struct dyn_ftrace *rec)
+{
+	char str[KSYM_SYMBOL_LEN];
+	unsigned long offset;
+	const char *ret;
+
+	ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
+
+	/* Weak functions can cause invalid addresses */
+	if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
+		rec->flags |= FTRACE_FL_DISABLED;
+		return 0;
+	}
+	return 1;
+}
+
+static struct workqueue_struct *ftrace_check_wq __initdata;
+static struct work_struct ftrace_check_work __initdata;
+
+/*
+ * Scan all the mcount/fentry entries to make sure they are valid.
+ */
+static __init void ftrace_check_work_func(struct work_struct *work)
+{
+	struct ftrace_page *pg;
+	struct dyn_ftrace *rec;
+
+	mutex_lock(&ftrace_lock);
+	do_for_each_ftrace_rec(pg, rec) {
+		test_for_valid_rec(rec);
+	} while_for_each_ftrace_rec();
+	mutex_unlock(&ftrace_lock);
+}
+
+static int __init ftrace_check_for_weak_functions(void)
+{
+	INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
+
+	ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
+
+	queue_work(ftrace_check_wq, &ftrace_check_work);
+	return 0;
+}
+
+static int __init ftrace_check_sync(void)
+{
+	/* Make sure the ftrace_check updates are finished */
+	if (ftrace_check_wq)
+		destroy_workqueue(ftrace_check_wq);
+	return 0;
+}
+
+late_initcall_sync(ftrace_check_sync);
+subsys_initcall(ftrace_check_for_weak_functions);
+
+static int print_rec(struct seq_file *m, unsigned long ip)
+{
+	unsigned long offset;
+	char str[KSYM_SYMBOL_LEN];
+	char *modname;
+	const char *ret;
+
+	ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
+	/* Weak functions can cause invalid addresses */
+	if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
+		snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
+			 FTRACE_INVALID_FUNCTION, offset);
+		ret = NULL;
+	}
+
+	seq_puts(m, str);
+	if (modname)
+		seq_printf(m, " [%s]", modname);
+	return ret == NULL ? -1 : 0;
+}
+#else
+static inline int test_for_valid_rec(struct dyn_ftrace *rec)
+{
+	return 1;
+}
+
+static inline int print_rec(struct seq_file *m, unsigned long ip)
+{
+	seq_printf(m, "%ps", (void *)ip);
+	return 0;
+}
+#endif
+
+static int t_show(struct seq_file *m, void *v)
+{
+	struct ftrace_iterator *iter = m->private;
+	struct dyn_ftrace *rec;
+
+	if (iter->flags & FTRACE_ITER_PROBE)
+		return t_probe_show(m, iter);
+
+	if (iter->flags & FTRACE_ITER_MOD)
+		return t_mod_show(m, iter);
+
+	if (iter->flags & FTRACE_ITER_PRINTALL) {
+		if (iter->flags & FTRACE_ITER_NOTRACE)
+			seq_puts(m, "#### no functions disabled ####\n");
+		else
+			seq_puts(m, "#### all functions enabled ####\n");
+		return 0;
+	}
+
+	rec = iter->func;
+
+	if (!rec)
+		return 0;
+
+	if (print_rec(m, rec->ip)) {
+		/* This should only happen when a rec is disabled */
+		WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
+		seq_putc(m, '\n');
+		return 0;
+	}
+
+	if (iter->flags & FTRACE_ITER_ENABLED) {
+		struct ftrace_ops *ops;
+
+		seq_printf(m, " (%ld)%s%s%s",
+			   ftrace_rec_count(rec),
+			   rec->flags & FTRACE_FL_REGS ? " R" : "  ",
+			   rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ",
+			   rec->flags & FTRACE_FL_DIRECT ? " D" : "  ");
+		if (rec->flags & FTRACE_FL_TRAMP_EN) {
+			ops = ftrace_find_tramp_ops_any(rec);
+			if (ops) {
+				do {
+					seq_printf(m, "\ttramp: %pS (%pS)",
+						   (void *)ops->trampoline,
+						   (void *)ops->func);
+					add_trampoline_func(m, ops, rec);
+					ops = ftrace_find_tramp_ops_next(rec, ops);
+				} while (ops);
+			} else
+				seq_puts(m, "\ttramp: ERROR!");
+		} else {
+			add_trampoline_func(m, NULL, rec);
+		}
+		if (rec->flags & FTRACE_FL_DIRECT) {
+			unsigned long direct;
+
+			direct = ftrace_find_rec_direct(rec->ip);
+			if (direct)
+				seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
+		}
+	}
+
+	seq_putc(m, '\n');
+
+	return 0;
+}
+
+static const struct seq_operations show_ftrace_seq_ops = {
+	.start = t_start,
+	.next = t_next,
+	.stop = t_stop,
+	.show = t_show,
+};
+
+static int
+ftrace_avail_open(struct inode *inode, struct file *file)
+{
+	struct ftrace_iterator *iter;
+	int ret;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	if (unlikely(ftrace_disabled))
+		return -ENODEV;
+
+	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
+	if (!iter)
+		return -ENOMEM;
+
+	iter->pg = ftrace_pages_start;
+	iter->ops = &global_ops;
+
+	return 0;
+}
+
+static int
+ftrace_enabled_open(struct inode *inode, struct file *file)
+{
+	struct ftrace_iterator *iter;
+
+	/*
+	 * This shows us what functions are currently being
+	 * traced and by what. Not sure if we want lockdown
+	 * to hide such critical information for an admin.
+	 * Although, perhaps it can show information we don't
+	 * want people to see, but if something is tracing
+	 * something, we probably want to know about it.
+	 */
+
+	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
+	if (!iter)
+		return -ENOMEM;
+
+	iter->pg = ftrace_pages_start;
+	iter->flags = FTRACE_ITER_ENABLED;
+	iter->ops = &global_ops;
+
+	return 0;
+}
+
+/**
+ * ftrace_regex_open - initialize function tracer filter files
+ * @ops: The ftrace_ops that hold the hash filters
+ * @flag: The type of filter to process
+ * @inode: The inode, usually passed in to your open routine
+ * @file: The file, usually passed in to your open routine
+ *
+ * ftrace_regex_open() initializes the filter files for the
+ * @ops. Depending on @flag it may process the filter hash or
+ * the notrace hash of @ops. With this called from the open
+ * routine, you can use ftrace_filter_write() for the write
+ * routine if @flag has FTRACE_ITER_FILTER set, or
+ * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
+ * tracing_lseek() should be used as the lseek routine, and
+ * release must call ftrace_regex_release().
+ */
+int
+ftrace_regex_open(struct ftrace_ops *ops, int flag,
+		  struct inode *inode, struct file *file)
+{
+	struct ftrace_iterator *iter;
+	struct ftrace_hash *hash;
+	struct list_head *mod_head;
+	struct trace_array *tr = ops->private;
+	int ret = -ENOMEM;
+
+	ftrace_ops_init(ops);
+
+	if (unlikely(ftrace_disabled))
+		return -ENODEV;
+
+	if (tracing_check_open_get_tr(tr))
+		return -ENODEV;
+
+	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+	if (!iter)
+		goto out;
+
+	if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
+		goto out;
+
+	iter->ops = ops;
+	iter->flags = flag;
+	iter->tr = tr;
+
+	mutex_lock(&ops->func_hash->regex_lock);
+
+	if (flag & FTRACE_ITER_NOTRACE) {
+		hash = ops->func_hash->notrace_hash;
+		mod_head = tr ? &tr->mod_notrace : NULL;
+	} else {
+		hash = ops->func_hash->filter_hash;
+		mod_head = tr ? &tr->mod_trace : NULL;
+	}
+
+	iter->mod_list = mod_head;
+
+	if (file->f_mode & FMODE_WRITE) {
+		const int size_bits = FTRACE_HASH_DEFAULT_BITS;
+
+		if (file->f_flags & O_TRUNC) {
+			iter->hash = alloc_ftrace_hash(size_bits);
+			clear_ftrace_mod_list(mod_head);
+	        } else {
+			iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
+		}
+
+		if (!iter->hash) {
+			trace_parser_put(&iter->parser);
+			goto out_unlock;
+		}
+	} else
+		iter->hash = hash;
+
+	ret = 0;
+
+	if (file->f_mode & FMODE_READ) {
+		iter->pg = ftrace_pages_start;
+
+		ret = seq_open(file, &show_ftrace_seq_ops);
+		if (!ret) {
+			struct seq_file *m = file->private_data;
+			m->private = iter;
+		} else {
+			/* Failed */
+			free_ftrace_hash(iter->hash);
+			trace_parser_put(&iter->parser);
+		}
+	} else
+		file->private_data = iter;
+
+ out_unlock:
+	mutex_unlock(&ops->func_hash->regex_lock);
+
+ out:
+	if (ret) {
+		kfree(iter);
+		if (tr)
+			trace_array_put(tr);
+	}
+
+	return ret;
+}
+
+static int
+ftrace_filter_open(struct inode *inode, struct file *file)
+{
+	struct ftrace_ops *ops = inode->i_private;
+
+	/* Checks for tracefs lockdown */
+	return ftrace_regex_open(ops,
+			FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
+			inode, file);
+}
+
+static int
+ftrace_notrace_open(struct inode *inode, struct file *file)
+{
+	struct ftrace_ops *ops = inode->i_private;
+
+	/* Checks for tracefs lockdown */
+	return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
+				 inode, file);
+}
+
+/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
+struct ftrace_glob {
+	char *search;
+	unsigned len;
+	int type;
+};
+
+/*
+ * If symbols in an architecture don't correspond exactly to the user-visible
+ * name of what they represent, it is possible to define this function to
+ * perform the necessary adjustments.
+*/
+char * __weak arch_ftrace_match_adjust(char *str, const char *search)
+{
+	return str;
+}
+
+static int ftrace_match(char *str, struct ftrace_glob *g)
+{
+	int matched = 0;
+	int slen;
+
+	str = arch_ftrace_match_adjust(str, g->search);
+
+	switch (g->type) {
+	case MATCH_FULL:
+		if (strcmp(str, g->search) == 0)
+			matched = 1;
+		break;
+	case MATCH_FRONT_ONLY:
+		if (strncmp(str, g->search, g->len) == 0)
+			matched = 1;
+		break;
+	case MATCH_MIDDLE_ONLY:
+		if (strstr(str, g->search))
+			matched = 1;
+		break;
+	case MATCH_END_ONLY:
+		slen = strlen(str);
+		if (slen >= g->len &&
+		    memcmp(str + slen - g->len, g->search, g->len) == 0)
+			matched = 1;
+		break;
+	case MATCH_GLOB:
+		if (glob_match(g->search, str))
+			matched = 1;
+		break;
+	}
+
+	return matched;
+}
+
+static int
+enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
+{
+	struct ftrace_func_entry *entry;
+	int ret = 0;
+
+	entry = ftrace_lookup_ip(hash, rec->ip);
+	if (clear_filter) {
+		/* Do nothing if it doesn't exist */
+		if (!entry)
+			return 0;
+
+		free_hash_entry(hash, entry);
+	} else {
+		/* Do nothing if it exists */
+		if (entry)
+			return 0;
+
+		ret = add_hash_entry(hash, rec->ip);
+	}
+	return ret;
+}
+
+static int
+add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
+		 int clear_filter)
+{
+	long index = simple_strtoul(func_g->search, NULL, 0);
+	struct ftrace_page *pg;
+	struct dyn_ftrace *rec;
+
+	/* The index starts at 1 */
+	if (--index < 0)
+		return 0;
+
+	do_for_each_ftrace_rec(pg, rec) {
+		if (pg->index <= index) {
+			index -= pg->index;
+			/* this is a double loop, break goes to the next page */
+			break;
+		}
+		rec = &pg->records[index];
+		enter_record(hash, rec, clear_filter);
+		return 1;
+	} while_for_each_ftrace_rec();
+	return 0;
+}
+
+#ifdef FTRACE_MCOUNT_MAX_OFFSET
+static int lookup_ip(unsigned long ip, char **modname, char *str)
+{
+	unsigned long offset;
+
+	kallsyms_lookup(ip, NULL, &offset, modname, str);
+	if (offset > FTRACE_MCOUNT_MAX_OFFSET)
+		return -1;
+	return 0;
+}
+#else
+static int lookup_ip(unsigned long ip, char **modname, char *str)
+{
+	kallsyms_lookup(ip, NULL, NULL, modname, str);
+	return 0;
+}
+#endif
+
+static int
+ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
+		struct ftrace_glob *mod_g, int exclude_mod)
+{
+	char str[KSYM_SYMBOL_LEN];
+	char *modname;
+
+	if (lookup_ip(rec->ip, &modname, str)) {
+		/* This should only happen when a rec is disabled */
+		WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
+			     !(rec->flags & FTRACE_FL_DISABLED));
+		return 0;
+	}
+
+	if (mod_g) {
+		int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
+
+		/* blank module name to match all modules */
+		if (!mod_g->len) {
+			/* blank module globbing: modname xor exclude_mod */
+			if (!exclude_mod != !modname)
+				goto func_match;
+			return 0;
+		}
+
+		/*
+		 * exclude_mod is set to trace everything but the given
+		 * module. If it is set and the module matches, then
+		 * return 0. If it is not set, and the module doesn't match
+		 * also return 0. Otherwise, check the function to see if
+		 * that matches.
+		 */
+		if (!mod_matches == !exclude_mod)
+			return 0;
+func_match:
+		/* blank search means to match all funcs in the mod */
+		if (!func_g->len)
+			return 1;
+	}
+
+	return ftrace_match(str, func_g);
+}
+
+static int
+match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
+{
+	struct ftrace_page *pg;
+	struct dyn_ftrace *rec;
+	struct ftrace_glob func_g = { .type = MATCH_FULL };
+	struct ftrace_glob mod_g = { .type = MATCH_FULL };
+	struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
+	int exclude_mod = 0;
+	int found = 0;
+	int ret;
+	int clear_filter = 0;
+
+	if (func) {
+		func_g.type = filter_parse_regex(func, len, &func_g.search,
+						 &clear_filter);
+		func_g.len = strlen(func_g.search);
+	}
+
+	if (mod) {
+		mod_g.type = filter_parse_regex(mod, strlen(mod),
+				&mod_g.search, &exclude_mod);
+		mod_g.len = strlen(mod_g.search);
+	}
+
+	mutex_lock(&ftrace_lock);
+
+	if (unlikely(ftrace_disabled))
+		goto out_unlock;
+
+	if (func_g.type == MATCH_INDEX) {
+		found = add_rec_by_index(hash, &func_g, clear_filter);
+		goto out_unlock;
+	}
+
+	do_for_each_ftrace_rec(pg, rec) {
+
+		if (rec->flags & FTRACE_FL_DISABLED)
+			continue;
+
+		if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
+			ret = enter_record(hash, rec, clear_filter);
+			if (ret < 0) {
+				found = ret;
+				goto out_unlock;
+			}
+			found = 1;
+		}
+	} while_for_each_ftrace_rec();
+ out_unlock:
+	mutex_unlock(&ftrace_lock);
+
+	return found;
+}
+
+static int
+ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
+{
+	return match_records(hash, buff, len, NULL);
+}
+
+static void ftrace_ops_update_code(struct ftrace_ops *ops,
+				   struct ftrace_ops_hash *old_hash)
+{
+	struct ftrace_ops *op;
+
+	if (!ftrace_enabled)
+		return;
+
+	if (ops->flags & FTRACE_OPS_FL_ENABLED) {
+		ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
+		return;
+	}
+
+	/*
+	 * If this is the shared global_ops filter, then we need to
+	 * check if there is another ops that shares it, is enabled.
+	 * If so, we still need to run the modify code.
+	 */
+	if (ops->func_hash != &global_ops.local_hash)
+		return;
+
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		if (op->func_hash == &global_ops.local_hash &&
+		    op->flags & FTRACE_OPS_FL_ENABLED) {
+			ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
+			/* Only need to do this once */
+			return;
+		}
+	} while_for_each_ftrace_op(op);
+}
+
+static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
+					   struct ftrace_hash **orig_hash,
+					   struct ftrace_hash *hash,
+					   int enable)
+{
+	struct ftrace_ops_hash old_hash_ops;
+	struct ftrace_hash *old_hash;
+	int ret;
+
+	old_hash = *orig_hash;
+	old_hash_ops.filter_hash = ops->func_hash->filter_hash;
+	old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
+	ret = ftrace_hash_move(ops, enable, orig_hash, hash);
+	if (!ret) {
+		ftrace_ops_update_code(ops, &old_hash_ops);
+		free_ftrace_hash_rcu(old_hash);
+	}
+	return ret;
+}
+
+static bool module_exists(const char *module)
+{
+	/* All modules have the symbol __this_module */
+	static const char this_mod[] = "__this_module";
+	char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
+	unsigned long val;
+	int n;
+
+	n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
+
+	if (n > sizeof(modname) - 1)
+		return false;
+
+	val = module_kallsyms_lookup_name(modname);
+	return val != 0;
+}
+
+static int cache_mod(struct trace_array *tr,
+		     const char *func, char *module, int enable)
+{
+	struct ftrace_mod_load *ftrace_mod, *n;
+	struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
+	int ret;
+
+	mutex_lock(&ftrace_lock);
+
+	/* We do not cache inverse filters */
+	if (func[0] == '!') {
+		func++;
+		ret = -EINVAL;
+
+		/* Look to remove this hash */
+		list_for_each_entry_safe(ftrace_mod, n, head, list) {
+			if (strcmp(ftrace_mod->module, module) != 0)
+				continue;
+
+			/* no func matches all */
+			if (strcmp(func, "*") == 0 ||
+			    (ftrace_mod->func &&
+			     strcmp(ftrace_mod->func, func) == 0)) {
+				ret = 0;
+				free_ftrace_mod(ftrace_mod);
+				continue;
+			}
+		}
+		goto out;
+	}
+
+	ret = -EINVAL;
+	/* We only care about modules that have not been loaded yet */
+	if (module_exists(module))
+		goto out;
+
+	/* Save this string off, and execute it when the module is loaded */
+	ret = ftrace_add_mod(tr, func, module, enable);
+ out:
+	mutex_unlock(&ftrace_lock);
+
+	return ret;
+}
+
+static int
+ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
+		 int reset, int enable);
+
+#ifdef CONFIG_MODULES
+static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
+			     char *mod, bool enable)
+{
+	struct ftrace_mod_load *ftrace_mod, *n;
+	struct ftrace_hash **orig_hash, *new_hash;
+	LIST_HEAD(process_mods);
+	char *func;
+
+	mutex_lock(&ops->func_hash->regex_lock);
+
+	if (enable)
+		orig_hash = &ops->func_hash->filter_hash;
+	else
+		orig_hash = &ops->func_hash->notrace_hash;
+
+	new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
+					      *orig_hash);
+	if (!new_hash)
+		goto out; /* warn? */
+
+	mutex_lock(&ftrace_lock);
+
+	list_for_each_entry_safe(ftrace_mod, n, head, list) {
+
+		if (strcmp(ftrace_mod->module, mod) != 0)
+			continue;
+
+		if (ftrace_mod->func)
+			func = kstrdup(ftrace_mod->func, GFP_KERNEL);
+		else
+			func = kstrdup("*", GFP_KERNEL);
+
+		if (!func) /* warn? */
+			continue;
+
+		list_move(&ftrace_mod->list, &process_mods);
+
+		/* Use the newly allocated func, as it may be "*" */
+		kfree(ftrace_mod->func);
+		ftrace_mod->func = func;
+	}
+
+	mutex_unlock(&ftrace_lock);
+
+	list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
+
+		func = ftrace_mod->func;
+
+		/* Grabs ftrace_lock, which is why we have this extra step */
+		match_records(new_hash, func, strlen(func), mod);
+		free_ftrace_mod(ftrace_mod);
+	}
+
+	if (enable && list_empty(head))
+		new_hash->flags &= ~FTRACE_HASH_FL_MOD;
+
+	mutex_lock(&ftrace_lock);
+
+	ftrace_hash_move_and_update_ops(ops, orig_hash,
+					      new_hash, enable);
+	mutex_unlock(&ftrace_lock);
+
+ out:
+	mutex_unlock(&ops->func_hash->regex_lock);
+
+	free_ftrace_hash(new_hash);
+}
+
+static void process_cached_mods(const char *mod_name)
+{
+	struct trace_array *tr;
+	char *mod;
+
+	mod = kstrdup(mod_name, GFP_KERNEL);
+	if (!mod)
+		return;
+
+	mutex_lock(&trace_types_lock);
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (!list_empty(&tr->mod_trace))
+			process_mod_list(&tr->mod_trace, tr->ops, mod, true);
+		if (!list_empty(&tr->mod_notrace))
+			process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
+	}
+	mutex_unlock(&trace_types_lock);
+
+	kfree(mod);
+}
+#endif
+
+/*
+ * We register the module command as a template to show others how
+ * to register the a command as well.
+ */
+
+static int
+ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
+		    char *func_orig, char *cmd, char *module, int enable)
+{
+	char *func;
+	int ret;
+
+	/* match_records() modifies func, and we need the original */
+	func = kstrdup(func_orig, GFP_KERNEL);
+	if (!func)
+		return -ENOMEM;
+
+	/*
+	 * cmd == 'mod' because we only registered this func
+	 * for the 'mod' ftrace_func_command.
+	 * But if you register one func with multiple commands,
+	 * you can tell which command was used by the cmd
+	 * parameter.
+	 */
+	ret = match_records(hash, func, strlen(func), module);
+	kfree(func);
+
+	if (!ret)
+		return cache_mod(tr, func_orig, module, enable);
+	if (ret < 0)
+		return ret;
+	return 0;
+}
+
+static struct ftrace_func_command ftrace_mod_cmd = {
+	.name			= "mod",
+	.func			= ftrace_mod_callback,
+};
+
+static int __init ftrace_mod_cmd_init(void)
+{
+	return register_ftrace_command(&ftrace_mod_cmd);
+}
+core_initcall(ftrace_mod_cmd_init);
+
+static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
+				      struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	struct ftrace_probe_ops *probe_ops;
+	struct ftrace_func_probe *probe;
+
+	probe = container_of(op, struct ftrace_func_probe, ops);
+	probe_ops = probe->probe_ops;
+
+	/*
+	 * Disable preemption for these calls to prevent a RCU grace
+	 * period. This syncs the hash iteration and freeing of items
+	 * on the hash. rcu_read_lock is too dangerous here.
+	 */
+	preempt_disable_notrace();
+	probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
+	preempt_enable_notrace();
+}
+
+struct ftrace_func_map {
+	struct ftrace_func_entry	entry;
+	void				*data;
+};
+
+struct ftrace_func_mapper {
+	struct ftrace_hash		hash;
+};
+
+/**
+ * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
+ *
+ * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
+ */
+struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
+{
+	struct ftrace_hash *hash;
+
+	/*
+	 * The mapper is simply a ftrace_hash, but since the entries
+	 * in the hash are not ftrace_func_entry type, we define it
+	 * as a separate structure.
+	 */
+	hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
+	return (struct ftrace_func_mapper *)hash;
+}
+
+/**
+ * ftrace_func_mapper_find_ip - Find some data mapped to an ip
+ * @mapper: The mapper that has the ip maps
+ * @ip: the instruction pointer to find the data for
+ *
+ * Returns the data mapped to @ip if found otherwise NULL. The return
+ * is actually the address of the mapper data pointer. The address is
+ * returned for use cases where the data is no bigger than a long, and
+ * the user can use the data pointer as its data instead of having to
+ * allocate more memory for the reference.
+ */
+void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
+				  unsigned long ip)
+{
+	struct ftrace_func_entry *entry;
+	struct ftrace_func_map *map;
+
+	entry = ftrace_lookup_ip(&mapper->hash, ip);
+	if (!entry)
+		return NULL;
+
+	map = (struct ftrace_func_map *)entry;
+	return &map->data;
+}
+
+/**
+ * ftrace_func_mapper_add_ip - Map some data to an ip
+ * @mapper: The mapper that has the ip maps
+ * @ip: The instruction pointer address to map @data to
+ * @data: The data to map to @ip
+ *
+ * Returns 0 on success otherwise an error.
+ */
+int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
+			      unsigned long ip, void *data)
+{
+	struct ftrace_func_entry *entry;
+	struct ftrace_func_map *map;
+
+	entry = ftrace_lookup_ip(&mapper->hash, ip);
+	if (entry)
+		return -EBUSY;
+
+	map = kmalloc(sizeof(*map), GFP_KERNEL);
+	if (!map)
+		return -ENOMEM;
+
+	map->entry.ip = ip;
+	map->data = data;
+
+	__add_hash_entry(&mapper->hash, &map->entry);
+
+	return 0;
+}
+
+/**
+ * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
+ * @mapper: The mapper that has the ip maps
+ * @ip: The instruction pointer address to remove the data from
+ *
+ * Returns the data if it is found, otherwise NULL.
+ * Note, if the data pointer is used as the data itself, (see
+ * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
+ * if the data pointer was set to zero.
+ */
+void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
+				   unsigned long ip)
+{
+	struct ftrace_func_entry *entry;
+	struct ftrace_func_map *map;
+	void *data;
+
+	entry = ftrace_lookup_ip(&mapper->hash, ip);
+	if (!entry)
+		return NULL;
+
+	map = (struct ftrace_func_map *)entry;
+	data = map->data;
+
+	remove_hash_entry(&mapper->hash, entry);
+	kfree(entry);
+
+	return data;
+}
+
+/**
+ * free_ftrace_func_mapper - free a mapping of ips and data
+ * @mapper: The mapper that has the ip maps
+ * @free_func: A function to be called on each data item.
+ *
+ * This is used to free the function mapper. The @free_func is optional
+ * and can be used if the data needs to be freed as well.
+ */
+void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
+			     ftrace_mapper_func free_func)
+{
+	struct ftrace_func_entry *entry;
+	struct ftrace_func_map *map;
+	struct hlist_head *hhd;
+	int size, i;
+
+	if (!mapper)
+		return;
+
+	if (free_func && mapper->hash.count) {
+		size = 1 << mapper->hash.size_bits;
+		for (i = 0; i < size; i++) {
+			hhd = &mapper->hash.buckets[i];
+			hlist_for_each_entry(entry, hhd, hlist) {
+				map = (struct ftrace_func_map *)entry;
+				free_func(map);
+			}
+		}
+	}
+	free_ftrace_hash(&mapper->hash);
+}
+
+static void release_probe(struct ftrace_func_probe *probe)
+{
+	struct ftrace_probe_ops *probe_ops;
+
+	mutex_lock(&ftrace_lock);
+
+	WARN_ON(probe->ref <= 0);
+
+	/* Subtract the ref that was used to protect this instance */
+	probe->ref--;
+
+	if (!probe->ref) {
+		probe_ops = probe->probe_ops;
+		/*
+		 * Sending zero as ip tells probe_ops to free
+		 * the probe->data itself
+		 */
+		if (probe_ops->free)
+			probe_ops->free(probe_ops, probe->tr, 0, probe->data);
+		list_del(&probe->list);
+		kfree(probe);
+	}
+	mutex_unlock(&ftrace_lock);
+}
+
+static void acquire_probe_locked(struct ftrace_func_probe *probe)
+{
+	/*
+	 * Add one ref to keep it from being freed when releasing the
+	 * ftrace_lock mutex.
+	 */
+	probe->ref++;
+}
+
+int
+register_ftrace_function_probe(char *glob, struct trace_array *tr,
+			       struct ftrace_probe_ops *probe_ops,
+			       void *data)
+{
+	struct ftrace_func_probe *probe = NULL, *iter;
+	struct ftrace_func_entry *entry;
+	struct ftrace_hash **orig_hash;
+	struct ftrace_hash *old_hash;
+	struct ftrace_hash *hash;
+	int count = 0;
+	int size;
+	int ret;
+	int i;
+
+	if (WARN_ON(!tr))
+		return -EINVAL;
+
+	/* We do not support '!' for function probes */
+	if (WARN_ON(glob[0] == '!'))
+		return -EINVAL;
+
+
+	mutex_lock(&ftrace_lock);
+	/* Check if the probe_ops is already registered */
+	list_for_each_entry(iter, &tr->func_probes, list) {
+		if (iter->probe_ops == probe_ops) {
+			probe = iter;
+			break;
+		}
+	}
+	if (!probe) {
+		probe = kzalloc(sizeof(*probe), GFP_KERNEL);
+		if (!probe) {
+			mutex_unlock(&ftrace_lock);
+			return -ENOMEM;
+		}
+		probe->probe_ops = probe_ops;
+		probe->ops.func = function_trace_probe_call;
+		probe->tr = tr;
+		ftrace_ops_init(&probe->ops);
+		list_add(&probe->list, &tr->func_probes);
+	}
+
+	acquire_probe_locked(probe);
+
+	mutex_unlock(&ftrace_lock);
+
+	/*
+	 * Note, there's a small window here that the func_hash->filter_hash
+	 * may be NULL or empty. Need to be careful when reading the loop.
+	 */
+	mutex_lock(&probe->ops.func_hash->regex_lock);
+
+	orig_hash = &probe->ops.func_hash->filter_hash;
+	old_hash = *orig_hash;
+	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
+
+	if (!hash) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = ftrace_match_records(hash, glob, strlen(glob));
+
+	/* Nothing found? */
+	if (!ret)
+		ret = -EINVAL;
+
+	if (ret < 0)
+		goto out;
+
+	size = 1 << hash->size_bits;
+	for (i = 0; i < size; i++) {
+		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
+			if (ftrace_lookup_ip(old_hash, entry->ip))
+				continue;
+			/*
+			 * The caller might want to do something special
+			 * for each function we find. We call the callback
+			 * to give the caller an opportunity to do so.
+			 */
+			if (probe_ops->init) {
+				ret = probe_ops->init(probe_ops, tr,
+						      entry->ip, data,
+						      &probe->data);
+				if (ret < 0) {
+					if (probe_ops->free && count)
+						probe_ops->free(probe_ops, tr,
+								0, probe->data);
+					probe->data = NULL;
+					goto out;
+				}
+			}
+			count++;
+		}
+	}
+
+	mutex_lock(&ftrace_lock);
+
+	if (!count) {
+		/* Nothing was added? */
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
+					      hash, 1);
+	if (ret < 0)
+		goto err_unlock;
+
+	/* One ref for each new function traced */
+	probe->ref += count;
+
+	if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
+		ret = ftrace_startup(&probe->ops, 0);
+
+ out_unlock:
+	mutex_unlock(&ftrace_lock);
+
+	if (!ret)
+		ret = count;
+ out:
+	mutex_unlock(&probe->ops.func_hash->regex_lock);
+	free_ftrace_hash(hash);
+
+	release_probe(probe);
+
+	return ret;
+
+ err_unlock:
+	if (!probe_ops->free || !count)
+		goto out_unlock;
+
+	/* Failed to do the move, need to call the free functions */
+	for (i = 0; i < size; i++) {
+		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
+			if (ftrace_lookup_ip(old_hash, entry->ip))
+				continue;
+			probe_ops->free(probe_ops, tr, entry->ip, probe->data);
+		}
+	}
+	goto out_unlock;
+}
+
+int
+unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
+				      struct ftrace_probe_ops *probe_ops)
+{
+	struct ftrace_func_probe *probe = NULL, *iter;
+	struct ftrace_ops_hash old_hash_ops;
+	struct ftrace_func_entry *entry;
+	struct ftrace_glob func_g;
+	struct ftrace_hash **orig_hash;
+	struct ftrace_hash *old_hash;
+	struct ftrace_hash *hash = NULL;
+	struct hlist_node *tmp;
+	struct hlist_head hhd;
+	char str[KSYM_SYMBOL_LEN];
+	int count = 0;
+	int i, ret = -ENODEV;
+	int size;
+
+	if (!glob || !strlen(glob) || !strcmp(glob, "*"))
+		func_g.search = NULL;
+	else {
+		int not;
+
+		func_g.type = filter_parse_regex(glob, strlen(glob),
+						 &func_g.search, &not);
+		func_g.len = strlen(func_g.search);
+
+		/* we do not support '!' for function probes */
+		if (WARN_ON(not))
+			return -EINVAL;
+	}
+
+	mutex_lock(&ftrace_lock);
+	/* Check if the probe_ops is already registered */
+	list_for_each_entry(iter, &tr->func_probes, list) {
+		if (iter->probe_ops == probe_ops) {
+			probe = iter;
+			break;
+		}
+	}
+	if (!probe)
+		goto err_unlock_ftrace;
+
+	ret = -EINVAL;
+	if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
+		goto err_unlock_ftrace;
+
+	acquire_probe_locked(probe);
+
+	mutex_unlock(&ftrace_lock);
+
+	mutex_lock(&probe->ops.func_hash->regex_lock);
+
+	orig_hash = &probe->ops.func_hash->filter_hash;
+	old_hash = *orig_hash;
+
+	if (ftrace_hash_empty(old_hash))
+		goto out_unlock;
+
+	old_hash_ops.filter_hash = old_hash;
+	/* Probes only have filters */
+	old_hash_ops.notrace_hash = NULL;
+
+	ret = -ENOMEM;
+	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
+	if (!hash)
+		goto out_unlock;
+
+	INIT_HLIST_HEAD(&hhd);
+
+	size = 1 << hash->size_bits;
+	for (i = 0; i < size; i++) {
+		hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
+
+			if (func_g.search) {
+				kallsyms_lookup(entry->ip, NULL, NULL,
+						NULL, str);
+				if (!ftrace_match(str, &func_g))
+					continue;
+			}
+			count++;
+			remove_hash_entry(hash, entry);
+			hlist_add_head(&entry->hlist, &hhd);
+		}
+	}
+
+	/* Nothing found? */
+	if (!count) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	mutex_lock(&ftrace_lock);
+
+	WARN_ON(probe->ref < count);
+
+	probe->ref -= count;
+
+	if (ftrace_hash_empty(hash))
+		ftrace_shutdown(&probe->ops, 0);
+
+	ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
+					      hash, 1);
+
+	/* still need to update the function call sites */
+	if (ftrace_enabled && !ftrace_hash_empty(hash))
+		ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
+				       &old_hash_ops);
+	synchronize_rcu();
+
+	hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
+		hlist_del(&entry->hlist);
+		if (probe_ops->free)
+			probe_ops->free(probe_ops, tr, entry->ip, probe->data);
+		kfree(entry);
+	}
+	mutex_unlock(&ftrace_lock);
+
+ out_unlock:
+	mutex_unlock(&probe->ops.func_hash->regex_lock);
+	free_ftrace_hash(hash);
+
+	release_probe(probe);
+
+	return ret;
+
+ err_unlock_ftrace:
+	mutex_unlock(&ftrace_lock);
+	return ret;
+}
+
+void clear_ftrace_function_probes(struct trace_array *tr)
+{
+	struct ftrace_func_probe *probe, *n;
+
+	list_for_each_entry_safe(probe, n, &tr->func_probes, list)
+		unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
+}
+
+static LIST_HEAD(ftrace_commands);
+static DEFINE_MUTEX(ftrace_cmd_mutex);
+
+/*
+ * Currently we only register ftrace commands from __init, so mark this
+ * __init too.
+ */
+__init int register_ftrace_command(struct ftrace_func_command *cmd)
+{
+	struct ftrace_func_command *p;
+	int ret = 0;
+
+	mutex_lock(&ftrace_cmd_mutex);
+	list_for_each_entry(p, &ftrace_commands, list) {
+		if (strcmp(cmd->name, p->name) == 0) {
+			ret = -EBUSY;
+			goto out_unlock;
+		}
+	}
+	list_add(&cmd->list, &ftrace_commands);
+ out_unlock:
+	mutex_unlock(&ftrace_cmd_mutex);
+
+	return ret;
+}
+
+/*
+ * Currently we only unregister ftrace commands from __init, so mark
+ * this __init too.
+ */
+__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
+{
+	struct ftrace_func_command *p, *n;
+	int ret = -ENODEV;
+
+	mutex_lock(&ftrace_cmd_mutex);
+	list_for_each_entry_safe(p, n, &ftrace_commands, list) {
+		if (strcmp(cmd->name, p->name) == 0) {
+			ret = 0;
+			list_del_init(&p->list);
+			goto out_unlock;
+		}
+	}
+ out_unlock:
+	mutex_unlock(&ftrace_cmd_mutex);
+
+	return ret;
+}
+
+static int ftrace_process_regex(struct ftrace_iterator *iter,
+				char *buff, int len, int enable)
+{
+	struct ftrace_hash *hash = iter->hash;
+	struct trace_array *tr = iter->ops->private;
+	char *func, *command, *next = buff;
+	struct ftrace_func_command *p;
+	int ret = -EINVAL;
+
+	func = strsep(&next, ":");
+
+	if (!next) {
+		ret = ftrace_match_records(hash, func, len);
+		if (!ret)
+			ret = -EINVAL;
+		if (ret < 0)
+			return ret;
+		return 0;
+	}
+
+	/* command found */
+
+	command = strsep(&next, ":");
+
+	mutex_lock(&ftrace_cmd_mutex);
+	list_for_each_entry(p, &ftrace_commands, list) {
+		if (strcmp(p->name, command) == 0) {
+			ret = p->func(tr, hash, func, command, next, enable);
+			goto out_unlock;
+		}
+	}
+ out_unlock:
+	mutex_unlock(&ftrace_cmd_mutex);
+
+	return ret;
+}
+
+static ssize_t
+ftrace_regex_write(struct file *file, const char __user *ubuf,
+		   size_t cnt, loff_t *ppos, int enable)
+{
+	struct ftrace_iterator *iter;
+	struct trace_parser *parser;
+	ssize_t ret, read;
+
+	if (!cnt)
+		return 0;
+
+	if (file->f_mode & FMODE_READ) {
+		struct seq_file *m = file->private_data;
+		iter = m->private;
+	} else
+		iter = file->private_data;
+
+	if (unlikely(ftrace_disabled))
+		return -ENODEV;
+
+	/* iter->hash is a local copy, so we don't need regex_lock */
+
+	parser = &iter->parser;
+	read = trace_get_user(parser, ubuf, cnt, ppos);
+
+	if (read >= 0 && trace_parser_loaded(parser) &&
+	    !trace_parser_cont(parser)) {
+		ret = ftrace_process_regex(iter, parser->buffer,
+					   parser->idx, enable);
+		trace_parser_clear(parser);
+		if (ret < 0)
+			goto out;
+	}
+
+	ret = read;
+ out:
+	return ret;
+}
+
+ssize_t
+ftrace_filter_write(struct file *file, const char __user *ubuf,
+		    size_t cnt, loff_t *ppos)
+{
+	return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
+}
+
+ssize_t
+ftrace_notrace_write(struct file *file, const char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
+}
+
+static int
+__ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
+{
+	struct ftrace_func_entry *entry;
+
+	ip = ftrace_location(ip);
+	if (!ip)
+		return -EINVAL;
+
+	if (remove) {
+		entry = ftrace_lookup_ip(hash, ip);
+		if (!entry)
+			return -ENOENT;
+		free_hash_entry(hash, entry);
+		return 0;
+	}
+
+	return add_hash_entry(hash, ip);
+}
+
+static int
+ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
+		  unsigned int cnt, int remove)
+{
+	unsigned int i;
+	int err;
+
+	for (i = 0; i < cnt; i++) {
+		err = __ftrace_match_addr(hash, ips[i], remove);
+		if (err) {
+			/*
+			 * This expects the @hash is a temporary hash and if this
+			 * fails the caller must free the @hash.
+			 */
+			return err;
+		}
+	}
+	return 0;
+}
+
+static int
+ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
+		unsigned long *ips, unsigned int cnt,
+		int remove, int reset, int enable)
+{
+	struct ftrace_hash **orig_hash;
+	struct ftrace_hash *hash;
+	int ret;
+
+	if (unlikely(ftrace_disabled))
+		return -ENODEV;
+
+	mutex_lock(&ops->func_hash->regex_lock);
+
+	if (enable)
+		orig_hash = &ops->func_hash->filter_hash;
+	else
+		orig_hash = &ops->func_hash->notrace_hash;
+
+	if (reset)
+		hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
+	else
+		hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
+
+	if (!hash) {
+		ret = -ENOMEM;
+		goto out_regex_unlock;
+	}
+
+	if (buf && !ftrace_match_records(hash, buf, len)) {
+		ret = -EINVAL;
+		goto out_regex_unlock;
+	}
+	if (ips) {
+		ret = ftrace_match_addr(hash, ips, cnt, remove);
+		if (ret < 0)
+			goto out_regex_unlock;
+	}
+
+	mutex_lock(&ftrace_lock);
+	ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
+	mutex_unlock(&ftrace_lock);
+
+ out_regex_unlock:
+	mutex_unlock(&ops->func_hash->regex_lock);
+
+	free_ftrace_hash(hash);
+	return ret;
+}
+
+static int
+ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
+		int remove, int reset, int enable)
+{
+	return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+
+struct ftrace_direct_func {
+	struct list_head	next;
+	unsigned long		addr;
+	int			count;
+};
+
+static LIST_HEAD(ftrace_direct_funcs);
+
+/**
+ * ftrace_find_direct_func - test an address if it is a registered direct caller
+ * @addr: The address of a registered direct caller
+ *
+ * This searches to see if a ftrace direct caller has been registered
+ * at a specific address, and if so, it returns a descriptor for it.
+ *
+ * This can be used by architecture code to see if an address is
+ * a direct caller (trampoline) attached to a fentry/mcount location.
+ * This is useful for the function_graph tracer, as it may need to
+ * do adjustments if it traced a location that also has a direct
+ * trampoline attached to it.
+ */
+struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
+{
+	struct ftrace_direct_func *entry;
+	bool found = false;
+
+	/* May be called by fgraph trampoline (protected by rcu tasks) */
+	list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
+		if (entry->addr == addr) {
+			found = true;
+			break;
+		}
+	}
+	if (found)
+		return entry;
+
+	return NULL;
+}
+
+static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
+{
+	struct ftrace_direct_func *direct;
+
+	direct = kmalloc(sizeof(*direct), GFP_KERNEL);
+	if (!direct)
+		return NULL;
+	direct->addr = addr;
+	direct->count = 0;
+	list_add_rcu(&direct->next, &ftrace_direct_funcs);
+	ftrace_direct_func_count++;
+	return direct;
+}
+
+static int register_ftrace_function_nolock(struct ftrace_ops *ops);
+
+/**
+ * register_ftrace_direct - Call a custom trampoline directly
+ * @ip: The address of the nop at the beginning of a function
+ * @addr: The address of the trampoline to call at @ip
+ *
+ * This is used to connect a direct call from the nop location (@ip)
+ * at the start of ftrace traced functions. The location that it calls
+ * (@addr) must be able to handle a direct call, and save the parameters
+ * of the function being traced, and restore them (or inject new ones
+ * if needed), before returning.
+ *
+ * Returns:
+ *  0 on success
+ *  -EBUSY - Another direct function is already attached (there can be only one)
+ *  -ENODEV - @ip does not point to a ftrace nop location (or not supported)
+ *  -ENOMEM - There was an allocation failure.
+ */
+int register_ftrace_direct(unsigned long ip, unsigned long addr)
+{
+	struct ftrace_direct_func *direct;
+	struct ftrace_func_entry *entry;
+	struct ftrace_hash *free_hash = NULL;
+	struct dyn_ftrace *rec;
+	int ret = -ENODEV;
+
+	mutex_lock(&direct_mutex);
+
+	ip = ftrace_location(ip);
+	if (!ip)
+		goto out_unlock;
+
+	/* See if there's a direct function at @ip already */
+	ret = -EBUSY;
+	if (ftrace_find_rec_direct(ip))
+		goto out_unlock;
+
+	ret = -ENODEV;
+	rec = lookup_rec(ip, ip);
+	if (!rec)
+		goto out_unlock;
+
+	/*
+	 * Check if the rec says it has a direct call but we didn't
+	 * find one earlier?
+	 */
+	if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
+		goto out_unlock;
+
+	/* Make sure the ip points to the exact record */
+	if (ip != rec->ip) {
+		ip = rec->ip;
+		/* Need to check this ip for a direct. */
+		if (ftrace_find_rec_direct(ip))
+			goto out_unlock;
+	}
+
+	ret = -ENOMEM;
+	direct = ftrace_find_direct_func(addr);
+	if (!direct) {
+		direct = ftrace_alloc_direct_func(addr);
+		if (!direct)
+			goto out_unlock;
+	}
+
+	entry = ftrace_add_rec_direct(ip, addr, &free_hash);
+	if (!entry)
+		goto out_unlock;
+
+	ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
+
+	if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
+		ret = register_ftrace_function_nolock(&direct_ops);
+		if (ret)
+			ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
+	}
+
+	if (ret) {
+		remove_hash_entry(direct_functions, entry);
+		kfree(entry);
+		if (!direct->count) {
+			list_del_rcu(&direct->next);
+			synchronize_rcu_tasks();
+			kfree(direct);
+			if (free_hash)
+				free_ftrace_hash(free_hash);
+			free_hash = NULL;
+			ftrace_direct_func_count--;
+		}
+	} else {
+		direct->count++;
+	}
+ out_unlock:
+	mutex_unlock(&direct_mutex);
+
+	if (free_hash) {
+		synchronize_rcu_tasks();
+		free_ftrace_hash(free_hash);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_ftrace_direct);
+
+static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
+						   struct dyn_ftrace **recp)
+{
+	struct ftrace_func_entry *entry;
+	struct dyn_ftrace *rec;
+
+	rec = lookup_rec(*ip, *ip);
+	if (!rec)
+		return NULL;
+
+	entry = __ftrace_lookup_ip(direct_functions, rec->ip);
+	if (!entry) {
+		WARN_ON(rec->flags & FTRACE_FL_DIRECT);
+		return NULL;
+	}
+
+	WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
+
+	/* Passed in ip just needs to be on the call site */
+	*ip = rec->ip;
+
+	if (recp)
+		*recp = rec;
+
+	return entry;
+}
+
+int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
+{
+	struct ftrace_direct_func *direct;
+	struct ftrace_func_entry *entry;
+	struct ftrace_hash *hash;
+	int ret = -ENODEV;
+
+	mutex_lock(&direct_mutex);
+
+	ip = ftrace_location(ip);
+	if (!ip)
+		goto out_unlock;
+
+	entry = find_direct_entry(&ip, NULL);
+	if (!entry)
+		goto out_unlock;
+
+	hash = direct_ops.func_hash->filter_hash;
+	if (hash->count == 1)
+		unregister_ftrace_function(&direct_ops);
+
+	ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
+
+	WARN_ON(ret);
+
+	remove_hash_entry(direct_functions, entry);
+
+	direct = ftrace_find_direct_func(addr);
+	if (!WARN_ON(!direct)) {
+		/* This is the good path (see the ! before WARN) */
+		direct->count--;
+		WARN_ON(direct->count < 0);
+		if (!direct->count) {
+			list_del_rcu(&direct->next);
+			synchronize_rcu_tasks();
+			kfree(direct);
+			kfree(entry);
+			ftrace_direct_func_count--;
+		}
+	}
+ out_unlock:
+	mutex_unlock(&direct_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
+
+static struct ftrace_ops stub_ops = {
+	.func		= ftrace_stub,
+};
+
+/**
+ * ftrace_modify_direct_caller - modify ftrace nop directly
+ * @entry: The ftrace hash entry of the direct helper for @rec
+ * @rec: The record representing the function site to patch
+ * @old_addr: The location that the site at @rec->ip currently calls
+ * @new_addr: The location that the site at @rec->ip should call
+ *
+ * An architecture may overwrite this function to optimize the
+ * changing of the direct callback on an ftrace nop location.
+ * This is called with the ftrace_lock mutex held, and no other
+ * ftrace callbacks are on the associated record (@rec). Thus,
+ * it is safe to modify the ftrace record, where it should be
+ * currently calling @old_addr directly, to call @new_addr.
+ *
+ * This is called with direct_mutex locked.
+ *
+ * Safety checks should be made to make sure that the code at
+ * @rec->ip is currently calling @old_addr. And this must
+ * also update entry->direct to @new_addr.
+ */
+int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
+				       struct dyn_ftrace *rec,
+				       unsigned long old_addr,
+				       unsigned long new_addr)
+{
+	unsigned long ip = rec->ip;
+	int ret;
+
+	lockdep_assert_held(&direct_mutex);
+
+	/*
+	 * The ftrace_lock was used to determine if the record
+	 * had more than one registered user to it. If it did,
+	 * we needed to prevent that from changing to do the quick
+	 * switch. But if it did not (only a direct caller was attached)
+	 * then this function is called. But this function can deal
+	 * with attached callers to the rec that we care about, and
+	 * since this function uses standard ftrace calls that take
+	 * the ftrace_lock mutex, we need to release it.
+	 */
+	mutex_unlock(&ftrace_lock);
+
+	/*
+	 * By setting a stub function at the same address, we force
+	 * the code to call the iterator and the direct_ops helper.
+	 * This means that @ip does not call the direct call, and
+	 * we can simply modify it.
+	 */
+	ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
+	if (ret)
+		goto out_lock;
+
+	ret = register_ftrace_function_nolock(&stub_ops);
+	if (ret) {
+		ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
+		goto out_lock;
+	}
+
+	entry->direct = new_addr;
+
+	/*
+	 * By removing the stub, we put back the direct call, calling
+	 * the @new_addr.
+	 */
+	unregister_ftrace_function(&stub_ops);
+	ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
+
+ out_lock:
+	mutex_lock(&ftrace_lock);
+
+	return ret;
+}
+
+/**
+ * modify_ftrace_direct - Modify an existing direct call to call something else
+ * @ip: The instruction pointer to modify
+ * @old_addr: The address that the current @ip calls directly
+ * @new_addr: The address that the @ip should call
+ *
+ * This modifies a ftrace direct caller at an instruction pointer without
+ * having to disable it first. The direct call will switch over to the
+ * @new_addr without missing anything.
+ *
+ * Returns: zero on success. Non zero on error, which includes:
+ *  -ENODEV : the @ip given has no direct caller attached
+ *  -EINVAL : the @old_addr does not match the current direct caller
+ */
+int modify_ftrace_direct(unsigned long ip,
+			 unsigned long old_addr, unsigned long new_addr)
+{
+	struct ftrace_direct_func *direct, *new_direct = NULL;
+	struct ftrace_func_entry *entry;
+	struct dyn_ftrace *rec;
+	int ret = -ENODEV;
+
+	mutex_lock(&direct_mutex);
+
+	mutex_lock(&ftrace_lock);
+
+	ip = ftrace_location(ip);
+	if (!ip)
+		goto out_unlock;
+
+	entry = find_direct_entry(&ip, &rec);
+	if (!entry)
+		goto out_unlock;
+
+	ret = -EINVAL;
+	if (entry->direct != old_addr)
+		goto out_unlock;
+
+	direct = ftrace_find_direct_func(old_addr);
+	if (WARN_ON(!direct))
+		goto out_unlock;
+	if (direct->count > 1) {
+		ret = -ENOMEM;
+		new_direct = ftrace_alloc_direct_func(new_addr);
+		if (!new_direct)
+			goto out_unlock;
+		direct->count--;
+		new_direct->count++;
+	} else {
+		direct->addr = new_addr;
+	}
+
+	/*
+	 * If there's no other ftrace callback on the rec->ip location,
+	 * then it can be changed directly by the architecture.
+	 * If there is another caller, then we just need to change the
+	 * direct caller helper to point to @new_addr.
+	 */
+	if (ftrace_rec_count(rec) == 1) {
+		ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
+	} else {
+		entry->direct = new_addr;
+		ret = 0;
+	}
+
+	if (ret) {
+		direct->addr = old_addr;
+		if (unlikely(new_direct)) {
+			direct->count++;
+			list_del_rcu(&new_direct->next);
+			synchronize_rcu_tasks();
+			kfree(new_direct);
+			ftrace_direct_func_count--;
+		}
+	}
+
+ out_unlock:
+	mutex_unlock(&ftrace_lock);
+	mutex_unlock(&direct_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(modify_ftrace_direct);
+
+#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
+
+static int check_direct_multi(struct ftrace_ops *ops)
+{
+	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
+		return -EINVAL;
+	if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
+		return -EINVAL;
+	return 0;
+}
+
+static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
+{
+	struct ftrace_func_entry *entry, *del;
+	int size, i;
+
+	size = 1 << hash->size_bits;
+	for (i = 0; i < size; i++) {
+		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
+			del = __ftrace_lookup_ip(direct_functions, entry->ip);
+			if (del && del->direct == addr) {
+				remove_hash_entry(direct_functions, del);
+				kfree(del);
+			}
+		}
+	}
+}
+
+/**
+ * register_ftrace_direct_multi - Call a custom trampoline directly
+ * for multiple functions registered in @ops
+ * @ops: The address of the struct ftrace_ops object
+ * @addr: The address of the trampoline to call at @ops functions
+ *
+ * This is used to connect a direct calls to @addr from the nop locations
+ * of the functions registered in @ops (with by ftrace_set_filter_ip
+ * function).
+ *
+ * The location that it calls (@addr) must be able to handle a direct call,
+ * and save the parameters of the function being traced, and restore them
+ * (or inject new ones if needed), before returning.
+ *
+ * Returns:
+ *  0 on success
+ *  -EINVAL  - The @ops object was already registered with this call or
+ *             when there are no functions in @ops object.
+ *  -EBUSY   - Another direct function is already attached (there can be only one)
+ *  -ENODEV  - @ip does not point to a ftrace nop location (or not supported)
+ *  -ENOMEM  - There was an allocation failure.
+ */
+int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+{
+	struct ftrace_hash *hash, *free_hash = NULL;
+	struct ftrace_func_entry *entry, *new;
+	int err = -EBUSY, size, i;
+
+	if (ops->func || ops->trampoline)
+		return -EINVAL;
+	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
+		return -EINVAL;
+	if (ops->flags & FTRACE_OPS_FL_ENABLED)
+		return -EINVAL;
+
+	hash = ops->func_hash->filter_hash;
+	if (ftrace_hash_empty(hash))
+		return -EINVAL;
+
+	mutex_lock(&direct_mutex);
+
+	/* Make sure requested entries are not already registered.. */
+	size = 1 << hash->size_bits;
+	for (i = 0; i < size; i++) {
+		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
+			if (ftrace_find_rec_direct(entry->ip))
+				goto out_unlock;
+		}
+	}
+
+	/* ... and insert them to direct_functions hash. */
+	err = -ENOMEM;
+	for (i = 0; i < size; i++) {
+		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
+			new = ftrace_add_rec_direct(entry->ip, addr, &free_hash);
+			if (!new)
+				goto out_remove;
+			entry->direct = addr;
+		}
+	}
+
+	ops->func = call_direct_funcs;
+	ops->flags = MULTI_FLAGS;
+	ops->trampoline = FTRACE_REGS_ADDR;
+
+	err = register_ftrace_function_nolock(ops);
+
+ out_remove:
+	if (err)
+		remove_direct_functions_hash(hash, addr);
+
+ out_unlock:
+	mutex_unlock(&direct_mutex);
+
+	if (free_hash) {
+		synchronize_rcu_tasks();
+		free_ftrace_hash(free_hash);
+	}
+	return err;
+}
+EXPORT_SYMBOL_GPL(register_ftrace_direct_multi);
+
+/**
+ * unregister_ftrace_direct_multi - Remove calls to custom trampoline
+ * previously registered by register_ftrace_direct_multi for @ops object.
+ * @ops: The address of the struct ftrace_ops object
+ *
+ * This is used to remove a direct calls to @addr from the nop locations
+ * of the functions registered in @ops (with by ftrace_set_filter_ip
+ * function).
+ *
+ * Returns:
+ *  0 on success
+ *  -EINVAL - The @ops object was not properly registered.
+ */
+int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+{
+	struct ftrace_hash *hash = ops->func_hash->filter_hash;
+	int err;
+
+	if (check_direct_multi(ops))
+		return -EINVAL;
+	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+		return -EINVAL;
+
+	mutex_lock(&direct_mutex);
+	err = unregister_ftrace_function(ops);
+	remove_direct_functions_hash(hash, addr);
+	mutex_unlock(&direct_mutex);
+
+	/* cleanup for possible another register call */
+	ops->func = NULL;
+	ops->trampoline = 0;
+	return err;
+}
+EXPORT_SYMBOL_GPL(unregister_ftrace_direct_multi);
+
+static int
+__modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+{
+	struct ftrace_hash *hash;
+	struct ftrace_func_entry *entry, *iter;
+	static struct ftrace_ops tmp_ops = {
+		.func		= ftrace_stub,
+		.flags		= FTRACE_OPS_FL_STUB,
+	};
+	int i, size;
+	int err;
+
+	lockdep_assert_held_once(&direct_mutex);
+
+	/* Enable the tmp_ops to have the same functions as the direct ops */
+	ftrace_ops_init(&tmp_ops);
+	tmp_ops.func_hash = ops->func_hash;
+
+	err = register_ftrace_function_nolock(&tmp_ops);
+	if (err)
+		return err;
+
+	/*
+	 * Now the ftrace_ops_list_func() is called to do the direct callers.
+	 * We can safely change the direct functions attached to each entry.
+	 */
+	mutex_lock(&ftrace_lock);
+
+	hash = ops->func_hash->filter_hash;
+	size = 1 << hash->size_bits;
+	for (i = 0; i < size; i++) {
+		hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
+			entry = __ftrace_lookup_ip(direct_functions, iter->ip);
+			if (!entry)
+				continue;
+			entry->direct = addr;
+		}
+	}
+
+	mutex_unlock(&ftrace_lock);
+
+	/* Removing the tmp_ops will add the updated direct callers to the functions */
+	unregister_ftrace_function(&tmp_ops);
+
+	return err;
+}
+
+/**
+ * modify_ftrace_direct_multi_nolock - Modify an existing direct 'multi' call
+ * to call something else
+ * @ops: The address of the struct ftrace_ops object
+ * @addr: The address of the new trampoline to call at @ops functions
+ *
+ * This is used to unregister currently registered direct caller and
+ * register new one @addr on functions registered in @ops object.
+ *
+ * Note there's window between ftrace_shutdown and ftrace_startup calls
+ * where there will be no callbacks called.
+ *
+ * Caller should already have direct_mutex locked, so we don't lock
+ * direct_mutex here.
+ *
+ * Returns: zero on success. Non zero on error, which includes:
+ *  -EINVAL - The @ops object was not properly registered.
+ */
+int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr)
+{
+	if (check_direct_multi(ops))
+		return -EINVAL;
+	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+		return -EINVAL;
+
+	return __modify_ftrace_direct_multi(ops, addr);
+}
+EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi_nolock);
+
+/**
+ * modify_ftrace_direct_multi - Modify an existing direct 'multi' call
+ * to call something else
+ * @ops: The address of the struct ftrace_ops object
+ * @addr: The address of the new trampoline to call at @ops functions
+ *
+ * This is used to unregister currently registered direct caller and
+ * register new one @addr on functions registered in @ops object.
+ *
+ * Note there's window between ftrace_shutdown and ftrace_startup calls
+ * where there will be no callbacks called.
+ *
+ * Returns: zero on success. Non zero on error, which includes:
+ *  -EINVAL - The @ops object was not properly registered.
+ */
+int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+{
+	int err;
+
+	if (check_direct_multi(ops))
+		return -EINVAL;
+	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+		return -EINVAL;
+
+	mutex_lock(&direct_mutex);
+	err = __modify_ftrace_direct_multi(ops, addr);
+	mutex_unlock(&direct_mutex);
+	return err;
+}
+EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi);
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
+
+/**
+ * ftrace_set_filter_ip - set a function to filter on in ftrace by address
+ * @ops - the ops to set the filter with
+ * @ip - the address to add to or remove from the filter.
+ * @remove - non zero to remove the ip from the filter
+ * @reset - non zero to reset all filters before applying this filter.
+ *
+ * Filters denote which functions should be enabled when tracing is enabled
+ * If @ip is NULL, it fails to update filter.
+ *
+ * This can allocate memory which must be freed before @ops can be freed,
+ * either by removing each filtered addr or by using
+ * ftrace_free_filter(@ops).
+ */
+int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
+			 int remove, int reset)
+{
+	ftrace_ops_init(ops);
+	return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
+}
+EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
+
+/**
+ * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
+ * @ops - the ops to set the filter with
+ * @ips - the array of addresses to add to or remove from the filter.
+ * @cnt - the number of addresses in @ips
+ * @remove - non zero to remove ips from the filter
+ * @reset - non zero to reset all filters before applying this filter.
+ *
+ * Filters denote which functions should be enabled when tracing is enabled
+ * If @ips array or any ip specified within is NULL , it fails to update filter.
+ *
+ * This can allocate memory which must be freed before @ops can be freed,
+ * either by removing each filtered addr or by using
+ * ftrace_free_filter(@ops).
+*/
+int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
+			  unsigned int cnt, int remove, int reset)
+{
+	ftrace_ops_init(ops);
+	return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
+}
+EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
+
+/**
+ * ftrace_ops_set_global_filter - setup ops to use global filters
+ * @ops - the ops which will use the global filters
+ *
+ * ftrace users who need global function trace filtering should call this.
+ * It can set the global filter only if ops were not initialized before.
+ */
+void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
+{
+	if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
+		return;
+
+	ftrace_ops_init(ops);
+	ops->func_hash = &global_ops.local_hash;
+}
+EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
+
+static int
+ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
+		 int reset, int enable)
+{
+	return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
+}
+
+/**
+ * ftrace_set_filter - set a function to filter on in ftrace
+ * @ops - the ops to set the filter with
+ * @buf - the string that holds the function filter text.
+ * @len - the length of the string.
+ * @reset - non zero to reset all filters before applying this filter.
+ *
+ * Filters denote which functions should be enabled when tracing is enabled.
+ * If @buf is NULL and reset is set, all functions will be enabled for tracing.
+ *
+ * This can allocate memory which must be freed before @ops can be freed,
+ * either by removing each filtered addr or by using
+ * ftrace_free_filter(@ops).
+ */
+int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
+		       int len, int reset)
+{
+	ftrace_ops_init(ops);
+	return ftrace_set_regex(ops, buf, len, reset, 1);
+}
+EXPORT_SYMBOL_GPL(ftrace_set_filter);
+
+/**
+ * ftrace_set_notrace - set a function to not trace in ftrace
+ * @ops - the ops to set the notrace filter with
+ * @buf - the string that holds the function notrace text.
+ * @len - the length of the string.
+ * @reset - non zero to reset all filters before applying this filter.
+ *
+ * Notrace Filters denote which functions should not be enabled when tracing
+ * is enabled. If @buf is NULL and reset is set, all functions will be enabled
+ * for tracing.
+ *
+ * This can allocate memory which must be freed before @ops can be freed,
+ * either by removing each filtered addr or by using
+ * ftrace_free_filter(@ops).
+ */
+int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
+			int len, int reset)
+{
+	ftrace_ops_init(ops);
+	return ftrace_set_regex(ops, buf, len, reset, 0);
+}
+EXPORT_SYMBOL_GPL(ftrace_set_notrace);
+/**
+ * ftrace_set_global_filter - set a function to filter on with global tracers
+ * @buf - the string that holds the function filter text.
+ * @len - the length of the string.
+ * @reset - non zero to reset all filters before applying this filter.
+ *
+ * Filters denote which functions should be enabled when tracing is enabled.
+ * If @buf is NULL and reset is set, all functions will be enabled for tracing.
+ */
+void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
+{
+	ftrace_set_regex(&global_ops, buf, len, reset, 1);
+}
+EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
+
+/**
+ * ftrace_set_global_notrace - set a function to not trace with global tracers
+ * @buf - the string that holds the function notrace text.
+ * @len - the length of the string.
+ * @reset - non zero to reset all filters before applying this filter.
+ *
+ * Notrace Filters denote which functions should not be enabled when tracing
+ * is enabled. If @buf is NULL and reset is set, all functions will be enabled
+ * for tracing.
+ */
+void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
+{
+	ftrace_set_regex(&global_ops, buf, len, reset, 0);
+}
+EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
+
+/*
+ * command line interface to allow users to set filters on boot up.
+ */
+#define FTRACE_FILTER_SIZE		COMMAND_LINE_SIZE
+static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
+static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
+
+/* Used by function selftest to not test if filter is set */
+bool ftrace_filter_param __initdata;
+
+static int __init set_ftrace_notrace(char *str)
+{
+	ftrace_filter_param = true;
+	strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
+	return 1;
+}
+__setup("ftrace_notrace=", set_ftrace_notrace);
+
+static int __init set_ftrace_filter(char *str)
+{
+	ftrace_filter_param = true;
+	strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
+	return 1;
+}
+__setup("ftrace_filter=", set_ftrace_filter);
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
+static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
+static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
+
+static int __init set_graph_function(char *str)
+{
+	strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
+	return 1;
+}
+__setup("ftrace_graph_filter=", set_graph_function);
+
+static int __init set_graph_notrace_function(char *str)
+{
+	strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
+	return 1;
+}
+__setup("ftrace_graph_notrace=", set_graph_notrace_function);
+
+static int __init set_graph_max_depth_function(char *str)
+{
+	if (!str)
+		return 0;
+	fgraph_max_depth = simple_strtoul(str, NULL, 0);
+	return 1;
+}
+__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
+
+static void __init set_ftrace_early_graph(char *buf, int enable)
+{
+	int ret;
+	char *func;
+	struct ftrace_hash *hash;
+
+	hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
+	if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
+		return;
+
+	while (buf) {
+		func = strsep(&buf, ",");
+		/* we allow only one expression at a time */
+		ret = ftrace_graph_set_hash(hash, func);
+		if (ret)
+			printk(KERN_DEBUG "ftrace: function %s not "
+					  "traceable\n", func);
+	}
+
+	if (enable)
+		ftrace_graph_hash = hash;
+	else
+		ftrace_graph_notrace_hash = hash;
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+void __init
+ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
+{
+	char *func;
+
+	ftrace_ops_init(ops);
+
+	while (buf) {
+		func = strsep(&buf, ",");
+		ftrace_set_regex(ops, func, strlen(func), 0, enable);
+	}
+}
+
+static void __init set_ftrace_early_filters(void)
+{
+	if (ftrace_filter_buf[0])
+		ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
+	if (ftrace_notrace_buf[0])
+		ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	if (ftrace_graph_buf[0])
+		set_ftrace_early_graph(ftrace_graph_buf, 1);
+	if (ftrace_graph_notrace_buf[0])
+		set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+}
+
+int ftrace_regex_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *m = (struct seq_file *)file->private_data;
+	struct ftrace_iterator *iter;
+	struct ftrace_hash **orig_hash;
+	struct trace_parser *parser;
+	int filter_hash;
+
+	if (file->f_mode & FMODE_READ) {
+		iter = m->private;
+		seq_release(inode, file);
+	} else
+		iter = file->private_data;
+
+	parser = &iter->parser;
+	if (trace_parser_loaded(parser)) {
+		int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
+
+		ftrace_process_regex(iter, parser->buffer,
+				     parser->idx, enable);
+	}
+
+	trace_parser_put(parser);
+
+	mutex_lock(&iter->ops->func_hash->regex_lock);
+
+	if (file->f_mode & FMODE_WRITE) {
+		filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
+
+		if (filter_hash) {
+			orig_hash = &iter->ops->func_hash->filter_hash;
+			if (iter->tr) {
+				if (list_empty(&iter->tr->mod_trace))
+					iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
+				else
+					iter->hash->flags |= FTRACE_HASH_FL_MOD;
+			}
+		} else
+			orig_hash = &iter->ops->func_hash->notrace_hash;
+
+		mutex_lock(&ftrace_lock);
+		ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
+						      iter->hash, filter_hash);
+		mutex_unlock(&ftrace_lock);
+	} else {
+		/* For read only, the hash is the ops hash */
+		iter->hash = NULL;
+	}
+
+	mutex_unlock(&iter->ops->func_hash->regex_lock);
+	free_ftrace_hash(iter->hash);
+	if (iter->tr)
+		trace_array_put(iter->tr);
+	kfree(iter);
+
+	return 0;
+}
+
+static const struct file_operations ftrace_avail_fops = {
+	.open = ftrace_avail_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release_private,
+};
+
+static const struct file_operations ftrace_enabled_fops = {
+	.open = ftrace_enabled_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release_private,
+};
+
+static const struct file_operations ftrace_filter_fops = {
+	.open = ftrace_filter_open,
+	.read = seq_read,
+	.write = ftrace_filter_write,
+	.llseek = tracing_lseek,
+	.release = ftrace_regex_release,
+};
+
+static const struct file_operations ftrace_notrace_fops = {
+	.open = ftrace_notrace_open,
+	.read = seq_read,
+	.write = ftrace_notrace_write,
+	.llseek = tracing_lseek,
+	.release = ftrace_regex_release,
+};
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+static DEFINE_MUTEX(graph_lock);
+
+struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
+struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
+
+enum graph_filter_type {
+	GRAPH_FILTER_NOTRACE	= 0,
+	GRAPH_FILTER_FUNCTION,
+};
+
+#define FTRACE_GRAPH_EMPTY	((void *)1)
+
+struct ftrace_graph_data {
+	struct ftrace_hash		*hash;
+	struct ftrace_func_entry	*entry;
+	int				idx;   /* for hash table iteration */
+	enum graph_filter_type		type;
+	struct ftrace_hash		*new_hash;
+	const struct seq_operations	*seq_ops;
+	struct trace_parser		parser;
+};
+
+static void *
+__g_next(struct seq_file *m, loff_t *pos)
+{
+	struct ftrace_graph_data *fgd = m->private;
+	struct ftrace_func_entry *entry = fgd->entry;
+	struct hlist_head *head;
+	int i, idx = fgd->idx;
+
+	if (*pos >= fgd->hash->count)
+		return NULL;
+
+	if (entry) {
+		hlist_for_each_entry_continue(entry, hlist) {
+			fgd->entry = entry;
+			return entry;
+		}
+
+		idx++;
+	}
+
+	for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
+		head = &fgd->hash->buckets[i];
+		hlist_for_each_entry(entry, head, hlist) {
+			fgd->entry = entry;
+			fgd->idx = i;
+			return entry;
+		}
+	}
+	return NULL;
+}
+
+static void *
+g_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	(*pos)++;
+	return __g_next(m, pos);
+}
+
+static void *g_start(struct seq_file *m, loff_t *pos)
+{
+	struct ftrace_graph_data *fgd = m->private;
+
+	mutex_lock(&graph_lock);
+
+	if (fgd->type == GRAPH_FILTER_FUNCTION)
+		fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
+					lockdep_is_held(&graph_lock));
+	else
+		fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
+					lockdep_is_held(&graph_lock));
+
+	/* Nothing, tell g_show to print all functions are enabled */
+	if (ftrace_hash_empty(fgd->hash) && !*pos)
+		return FTRACE_GRAPH_EMPTY;
+
+	fgd->idx = 0;
+	fgd->entry = NULL;
+	return __g_next(m, pos);
+}
+
+static void g_stop(struct seq_file *m, void *p)
+{
+	mutex_unlock(&graph_lock);
+}
+
+static int g_show(struct seq_file *m, void *v)
+{
+	struct ftrace_func_entry *entry = v;
+
+	if (!entry)
+		return 0;
+
+	if (entry == FTRACE_GRAPH_EMPTY) {
+		struct ftrace_graph_data *fgd = m->private;
+
+		if (fgd->type == GRAPH_FILTER_FUNCTION)
+			seq_puts(m, "#### all functions enabled ####\n");
+		else
+			seq_puts(m, "#### no functions disabled ####\n");
+		return 0;
+	}
+
+	seq_printf(m, "%ps\n", (void *)entry->ip);
+
+	return 0;
+}
+
+static const struct seq_operations ftrace_graph_seq_ops = {
+	.start = g_start,
+	.next = g_next,
+	.stop = g_stop,
+	.show = g_show,
+};
+
+static int
+__ftrace_graph_open(struct inode *inode, struct file *file,
+		    struct ftrace_graph_data *fgd)
+{
+	int ret;
+	struct ftrace_hash *new_hash = NULL;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	if (file->f_mode & FMODE_WRITE) {
+		const int size_bits = FTRACE_HASH_DEFAULT_BITS;
+
+		if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
+			return -ENOMEM;
+
+		if (file->f_flags & O_TRUNC)
+			new_hash = alloc_ftrace_hash(size_bits);
+		else
+			new_hash = alloc_and_copy_ftrace_hash(size_bits,
+							      fgd->hash);
+		if (!new_hash) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	}
+
+	if (file->f_mode & FMODE_READ) {
+		ret = seq_open(file, &ftrace_graph_seq_ops);
+		if (!ret) {
+			struct seq_file *m = file->private_data;
+			m->private = fgd;
+		} else {
+			/* Failed */
+			free_ftrace_hash(new_hash);
+			new_hash = NULL;
+		}
+	} else
+		file->private_data = fgd;
+
+out:
+	if (ret < 0 && file->f_mode & FMODE_WRITE)
+		trace_parser_put(&fgd->parser);
+
+	fgd->new_hash = new_hash;
+
+	/*
+	 * All uses of fgd->hash must be taken with the graph_lock
+	 * held. The graph_lock is going to be released, so force
+	 * fgd->hash to be reinitialized when it is taken again.
+	 */
+	fgd->hash = NULL;
+
+	return ret;
+}
+
+static int
+ftrace_graph_open(struct inode *inode, struct file *file)
+{
+	struct ftrace_graph_data *fgd;
+	int ret;
+
+	if (unlikely(ftrace_disabled))
+		return -ENODEV;
+
+	fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
+	if (fgd == NULL)
+		return -ENOMEM;
+
+	mutex_lock(&graph_lock);
+
+	fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
+					lockdep_is_held(&graph_lock));
+	fgd->type = GRAPH_FILTER_FUNCTION;
+	fgd->seq_ops = &ftrace_graph_seq_ops;
+
+	ret = __ftrace_graph_open(inode, file, fgd);
+	if (ret < 0)
+		kfree(fgd);
+
+	mutex_unlock(&graph_lock);
+	return ret;
+}
+
+static int
+ftrace_graph_notrace_open(struct inode *inode, struct file *file)
+{
+	struct ftrace_graph_data *fgd;
+	int ret;
+
+	if (unlikely(ftrace_disabled))
+		return -ENODEV;
+
+	fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
+	if (fgd == NULL)
+		return -ENOMEM;
+
+	mutex_lock(&graph_lock);
+
+	fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
+					lockdep_is_held(&graph_lock));
+	fgd->type = GRAPH_FILTER_NOTRACE;
+	fgd->seq_ops = &ftrace_graph_seq_ops;
+
+	ret = __ftrace_graph_open(inode, file, fgd);
+	if (ret < 0)
+		kfree(fgd);
+
+	mutex_unlock(&graph_lock);
+	return ret;
+}
+
+static int
+ftrace_graph_release(struct inode *inode, struct file *file)
+{
+	struct ftrace_graph_data *fgd;
+	struct ftrace_hash *old_hash, *new_hash;
+	struct trace_parser *parser;
+	int ret = 0;
+
+	if (file->f_mode & FMODE_READ) {
+		struct seq_file *m = file->private_data;
+
+		fgd = m->private;
+		seq_release(inode, file);
+	} else {
+		fgd = file->private_data;
+	}
+
+
+	if (file->f_mode & FMODE_WRITE) {
+
+		parser = &fgd->parser;
+
+		if (trace_parser_loaded((parser))) {
+			ret = ftrace_graph_set_hash(fgd->new_hash,
+						    parser->buffer);
+		}
+
+		trace_parser_put(parser);
+
+		new_hash = __ftrace_hash_move(fgd->new_hash);
+		if (!new_hash) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		mutex_lock(&graph_lock);
+
+		if (fgd->type == GRAPH_FILTER_FUNCTION) {
+			old_hash = rcu_dereference_protected(ftrace_graph_hash,
+					lockdep_is_held(&graph_lock));
+			rcu_assign_pointer(ftrace_graph_hash, new_hash);
+		} else {
+			old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
+					lockdep_is_held(&graph_lock));
+			rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
+		}
+
+		mutex_unlock(&graph_lock);
+
+		/*
+		 * We need to do a hard force of sched synchronization.
+		 * This is because we use preempt_disable() to do RCU, but
+		 * the function tracers can be called where RCU is not watching
+		 * (like before user_exit()). We can not rely on the RCU
+		 * infrastructure to do the synchronization, thus we must do it
+		 * ourselves.
+		 */
+		if (old_hash != EMPTY_HASH)
+			synchronize_rcu_tasks_rude();
+
+		free_ftrace_hash(old_hash);
+	}
+
+ out:
+	free_ftrace_hash(fgd->new_hash);
+	kfree(fgd);
+
+	return ret;
+}
+
+static int
+ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
+{
+	struct ftrace_glob func_g;
+	struct dyn_ftrace *rec;
+	struct ftrace_page *pg;
+	struct ftrace_func_entry *entry;
+	int fail = 1;
+	int not;
+
+	/* decode regex */
+	func_g.type = filter_parse_regex(buffer, strlen(buffer),
+					 &func_g.search, &not);
+
+	func_g.len = strlen(func_g.search);
+
+	mutex_lock(&ftrace_lock);
+
+	if (unlikely(ftrace_disabled)) {
+		mutex_unlock(&ftrace_lock);
+		return -ENODEV;
+	}
+
+	do_for_each_ftrace_rec(pg, rec) {
+
+		if (rec->flags & FTRACE_FL_DISABLED)
+			continue;
+
+		if (ftrace_match_record(rec, &func_g, NULL, 0)) {
+			entry = ftrace_lookup_ip(hash, rec->ip);
+
+			if (!not) {
+				fail = 0;
+
+				if (entry)
+					continue;
+				if (add_hash_entry(hash, rec->ip) < 0)
+					goto out;
+			} else {
+				if (entry) {
+					free_hash_entry(hash, entry);
+					fail = 0;
+				}
+			}
+		}
+	} while_for_each_ftrace_rec();
+out:
+	mutex_unlock(&ftrace_lock);
+
+	if (fail)
+		return -EINVAL;
+
+	return 0;
+}
+
+static ssize_t
+ftrace_graph_write(struct file *file, const char __user *ubuf,
+		   size_t cnt, loff_t *ppos)
+{
+	ssize_t read, ret = 0;
+	struct ftrace_graph_data *fgd = file->private_data;
+	struct trace_parser *parser;
+
+	if (!cnt)
+		return 0;
+
+	/* Read mode uses seq functions */
+	if (file->f_mode & FMODE_READ) {
+		struct seq_file *m = file->private_data;
+		fgd = m->private;
+	}
+
+	parser = &fgd->parser;
+
+	read = trace_get_user(parser, ubuf, cnt, ppos);
+
+	if (read >= 0 && trace_parser_loaded(parser) &&
+	    !trace_parser_cont(parser)) {
+
+		ret = ftrace_graph_set_hash(fgd->new_hash,
+					    parser->buffer);
+		trace_parser_clear(parser);
+	}
+
+	if (!ret)
+		ret = read;
+
+	return ret;
+}
+
+static const struct file_operations ftrace_graph_fops = {
+	.open		= ftrace_graph_open,
+	.read		= seq_read,
+	.write		= ftrace_graph_write,
+	.llseek		= tracing_lseek,
+	.release	= ftrace_graph_release,
+};
+
+static const struct file_operations ftrace_graph_notrace_fops = {
+	.open		= ftrace_graph_notrace_open,
+	.read		= seq_read,
+	.write		= ftrace_graph_write,
+	.llseek		= tracing_lseek,
+	.release	= ftrace_graph_release,
+};
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+void ftrace_create_filter_files(struct ftrace_ops *ops,
+				struct dentry *parent)
+{
+
+	trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
+			  ops, &ftrace_filter_fops);
+
+	trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
+			  ops, &ftrace_notrace_fops);
+}
+
+/*
+ * The name "destroy_filter_files" is really a misnomer. Although
+ * in the future, it may actually delete the files, but this is
+ * really intended to make sure the ops passed in are disabled
+ * and that when this function returns, the caller is free to
+ * free the ops.
+ *
+ * The "destroy" name is only to match the "create" name that this
+ * should be paired with.
+ */
+void ftrace_destroy_filter_files(struct ftrace_ops *ops)
+{
+	mutex_lock(&ftrace_lock);
+	if (ops->flags & FTRACE_OPS_FL_ENABLED)
+		ftrace_shutdown(ops, 0);
+	ops->flags |= FTRACE_OPS_FL_DELETED;
+	ftrace_free_filter(ops);
+	mutex_unlock(&ftrace_lock);
+}
+
+static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
+{
+
+	trace_create_file("available_filter_functions", TRACE_MODE_READ,
+			d_tracer, NULL, &ftrace_avail_fops);
+
+	trace_create_file("enabled_functions", TRACE_MODE_READ,
+			d_tracer, NULL, &ftrace_enabled_fops);
+
+	ftrace_create_filter_files(&global_ops, d_tracer);
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
+				    NULL,
+				    &ftrace_graph_fops);
+	trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
+				    NULL,
+				    &ftrace_graph_notrace_fops);
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+	return 0;
+}
+
+static int ftrace_cmp_ips(const void *a, const void *b)
+{
+	const unsigned long *ipa = a;
+	const unsigned long *ipb = b;
+
+	if (*ipa > *ipb)
+		return 1;
+	if (*ipa < *ipb)
+		return -1;
+	return 0;
+}
+
+#ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
+static void test_is_sorted(unsigned long *start, unsigned long count)
+{
+	int i;
+
+	for (i = 1; i < count; i++) {
+		if (WARN(start[i - 1] > start[i],
+			 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
+			 (void *)start[i - 1], start[i - 1],
+			 (void *)start[i], start[i]))
+			break;
+	}
+	if (i == count)
+		pr_info("ftrace section at %px sorted properly\n", start);
+}
+#else
+static void test_is_sorted(unsigned long *start, unsigned long count)
+{
+}
+#endif
+
+static int ftrace_process_locs(struct module *mod,
+			       unsigned long *start,
+			       unsigned long *end)
+{
+	struct ftrace_page *pg_unuse = NULL;
+	struct ftrace_page *start_pg;
+	struct ftrace_page *pg;
+	struct dyn_ftrace *rec;
+	unsigned long skipped = 0;
+	unsigned long count;
+	unsigned long *p;
+	unsigned long addr;
+	unsigned long flags = 0; /* Shut up gcc */
+	int ret = -ENOMEM;
+
+	count = end - start;
+
+	if (!count)
+		return 0;
+
+	/*
+	 * Sorting mcount in vmlinux at build time depend on
+	 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
+	 * modules can not be sorted at build time.
+	 */
+	if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
+		sort(start, count, sizeof(*start),
+		     ftrace_cmp_ips, NULL);
+	} else {
+		test_is_sorted(start, count);
+	}
+
+	start_pg = ftrace_allocate_pages(count);
+	if (!start_pg)
+		return -ENOMEM;
+
+	mutex_lock(&ftrace_lock);
+
+	/*
+	 * Core and each module needs their own pages, as
+	 * modules will free them when they are removed.
+	 * Force a new page to be allocated for modules.
+	 */
+	if (!mod) {
+		WARN_ON(ftrace_pages || ftrace_pages_start);
+		/* First initialization */
+		ftrace_pages = ftrace_pages_start = start_pg;
+	} else {
+		if (!ftrace_pages)
+			goto out;
+
+		if (WARN_ON(ftrace_pages->next)) {
+			/* Hmm, we have free pages? */
+			while (ftrace_pages->next)
+				ftrace_pages = ftrace_pages->next;
+		}
+
+		ftrace_pages->next = start_pg;
+	}
+
+	p = start;
+	pg = start_pg;
+	while (p < end) {
+		unsigned long end_offset;
+		addr = ftrace_call_adjust(*p++);
+		/*
+		 * Some architecture linkers will pad between
+		 * the different mcount_loc sections of different
+		 * object files to satisfy alignments.
+		 * Skip any NULL pointers.
+		 */
+		if (!addr) {
+			skipped++;
+			continue;
+		}
+
+		end_offset = (pg->index+1) * sizeof(pg->records[0]);
+		if (end_offset > PAGE_SIZE << pg->order) {
+			/* We should have allocated enough */
+			if (WARN_ON(!pg->next))
+				break;
+			pg = pg->next;
+		}
+
+		rec = &pg->records[pg->index++];
+		rec->ip = addr;
+	}
+
+	if (pg->next) {
+		pg_unuse = pg->next;
+		pg->next = NULL;
+	}
+
+	/* Assign the last page to ftrace_pages */
+	ftrace_pages = pg;
+
+	/*
+	 * We only need to disable interrupts on start up
+	 * because we are modifying code that an interrupt
+	 * may execute, and the modification is not atomic.
+	 * But for modules, nothing runs the code we modify
+	 * until we are finished with it, and there's no
+	 * reason to cause large interrupt latencies while we do it.
+	 */
+	if (!mod)
+		local_irq_save(flags);
+	ftrace_update_code(mod, start_pg);
+	if (!mod)
+		local_irq_restore(flags);
+	ret = 0;
+ out:
+	mutex_unlock(&ftrace_lock);
+
+	/* We should have used all pages unless we skipped some */
+	if (pg_unuse) {
+		WARN_ON(!skipped);
+		ftrace_free_pages(pg_unuse);
+	}
+	return ret;
+}
+
+struct ftrace_mod_func {
+	struct list_head	list;
+	char			*name;
+	unsigned long		ip;
+	unsigned int		size;
+};
+
+struct ftrace_mod_map {
+	struct rcu_head		rcu;
+	struct list_head	list;
+	struct module		*mod;
+	unsigned long		start_addr;
+	unsigned long		end_addr;
+	struct list_head	funcs;
+	unsigned int		num_funcs;
+};
+
+static int ftrace_get_trampoline_kallsym(unsigned int symnum,
+					 unsigned long *value, char *type,
+					 char *name, char *module_name,
+					 int *exported)
+{
+	struct ftrace_ops *op;
+
+	list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
+		if (!op->trampoline || symnum--)
+			continue;
+		*value = op->trampoline;
+		*type = 't';
+		strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
+		strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
+		*exported = 0;
+		return 0;
+	}
+
+	return -ERANGE;
+}
+
+#if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
+/*
+ * Check if the current ops references the given ip.
+ *
+ * If the ops traces all functions, then it was already accounted for.
+ * If the ops does not trace the current record function, skip it.
+ * If the ops ignores the function via notrace filter, skip it.
+ */
+static bool
+ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
+{
+	/* If ops isn't enabled, ignore it */
+	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+		return false;
+
+	/* If ops traces all then it includes this function */
+	if (ops_traces_mod(ops))
+		return true;
+
+	/* The function must be in the filter */
+	if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
+	    !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
+		return false;
+
+	/* If in notrace hash, we ignore it too */
+	if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
+		return false;
+
+	return true;
+}
+#endif
+
+#ifdef CONFIG_MODULES
+
+#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
+
+static LIST_HEAD(ftrace_mod_maps);
+
+static int referenced_filters(struct dyn_ftrace *rec)
+{
+	struct ftrace_ops *ops;
+	int cnt = 0;
+
+	for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
+		if (ops_references_ip(ops, rec->ip)) {
+			if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
+				continue;
+			if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
+				continue;
+			cnt++;
+			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
+				rec->flags |= FTRACE_FL_REGS;
+			if (cnt == 1 && ops->trampoline)
+				rec->flags |= FTRACE_FL_TRAMP;
+			else
+				rec->flags &= ~FTRACE_FL_TRAMP;
+		}
+	}
+
+	return cnt;
+}
+
+static void
+clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
+{
+	struct ftrace_func_entry *entry;
+	struct dyn_ftrace *rec;
+	int i;
+
+	if (ftrace_hash_empty(hash))
+		return;
+
+	for (i = 0; i < pg->index; i++) {
+		rec = &pg->records[i];
+		entry = __ftrace_lookup_ip(hash, rec->ip);
+		/*
+		 * Do not allow this rec to match again.
+		 * Yeah, it may waste some memory, but will be removed
+		 * if/when the hash is modified again.
+		 */
+		if (entry)
+			entry->ip = 0;
+	}
+}
+
+/* Clear any records from hashes */
+static void clear_mod_from_hashes(struct ftrace_page *pg)
+{
+	struct trace_array *tr;
+
+	mutex_lock(&trace_types_lock);
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (!tr->ops || !tr->ops->func_hash)
+			continue;
+		mutex_lock(&tr->ops->func_hash->regex_lock);
+		clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
+		clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
+		mutex_unlock(&tr->ops->func_hash->regex_lock);
+	}
+	mutex_unlock(&trace_types_lock);
+}
+
+static void ftrace_free_mod_map(struct rcu_head *rcu)
+{
+	struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
+	struct ftrace_mod_func *mod_func;
+	struct ftrace_mod_func *n;
+
+	/* All the contents of mod_map are now not visible to readers */
+	list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
+		kfree(mod_func->name);
+		list_del(&mod_func->list);
+		kfree(mod_func);
+	}
+
+	kfree(mod_map);
+}
+
+void ftrace_release_mod(struct module *mod)
+{
+	struct ftrace_mod_map *mod_map;
+	struct ftrace_mod_map *n;
+	struct dyn_ftrace *rec;
+	struct ftrace_page **last_pg;
+	struct ftrace_page *tmp_page = NULL;
+	struct ftrace_page *pg;
+
+	mutex_lock(&ftrace_lock);
+
+	if (ftrace_disabled)
+		goto out_unlock;
+
+	list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
+		if (mod_map->mod == mod) {
+			list_del_rcu(&mod_map->list);
+			call_rcu(&mod_map->rcu, ftrace_free_mod_map);
+			break;
+		}
+	}
+
+	/*
+	 * Each module has its own ftrace_pages, remove
+	 * them from the list.
+	 */
+	last_pg = &ftrace_pages_start;
+	for (pg = ftrace_pages_start; pg; pg = *last_pg) {
+		rec = &pg->records[0];
+		if (within_module_core(rec->ip, mod) ||
+		    within_module_init(rec->ip, mod)) {
+			/*
+			 * As core pages are first, the first
+			 * page should never be a module page.
+			 */
+			if (WARN_ON(pg == ftrace_pages_start))
+				goto out_unlock;
+
+			/* Check if we are deleting the last page */
+			if (pg == ftrace_pages)
+				ftrace_pages = next_to_ftrace_page(last_pg);
+
+			ftrace_update_tot_cnt -= pg->index;
+			*last_pg = pg->next;
+
+			pg->next = tmp_page;
+			tmp_page = pg;
+		} else
+			last_pg = &pg->next;
+	}
+ out_unlock:
+	mutex_unlock(&ftrace_lock);
+
+	for (pg = tmp_page; pg; pg = tmp_page) {
+
+		/* Needs to be called outside of ftrace_lock */
+		clear_mod_from_hashes(pg);
+
+		if (pg->records) {
+			free_pages((unsigned long)pg->records, pg->order);
+			ftrace_number_of_pages -= 1 << pg->order;
+		}
+		tmp_page = pg->next;
+		kfree(pg);
+		ftrace_number_of_groups--;
+	}
+}
+
+void ftrace_module_enable(struct module *mod)
+{
+	struct dyn_ftrace *rec;
+	struct ftrace_page *pg;
+
+	mutex_lock(&ftrace_lock);
+
+	if (ftrace_disabled)
+		goto out_unlock;
+
+	/*
+	 * If the tracing is enabled, go ahead and enable the record.
+	 *
+	 * The reason not to enable the record immediately is the
+	 * inherent check of ftrace_make_nop/ftrace_make_call for
+	 * correct previous instructions.  Making first the NOP
+	 * conversion puts the module to the correct state, thus
+	 * passing the ftrace_make_call check.
+	 *
+	 * We also delay this to after the module code already set the
+	 * text to read-only, as we now need to set it back to read-write
+	 * so that we can modify the text.
+	 */
+	if (ftrace_start_up)
+		ftrace_arch_code_modify_prepare();
+
+	do_for_each_ftrace_rec(pg, rec) {
+		int cnt;
+		/*
+		 * do_for_each_ftrace_rec() is a double loop.
+		 * module text shares the pg. If a record is
+		 * not part of this module, then skip this pg,
+		 * which the "break" will do.
+		 */
+		if (!within_module_core(rec->ip, mod) &&
+		    !within_module_init(rec->ip, mod))
+			break;
+
+		/* Weak functions should still be ignored */
+		if (!test_for_valid_rec(rec)) {
+			/* Clear all other flags. Should not be enabled anyway */
+			rec->flags = FTRACE_FL_DISABLED;
+			continue;
+		}
+
+		cnt = 0;
+
+		/*
+		 * When adding a module, we need to check if tracers are
+		 * currently enabled and if they are, and can trace this record,
+		 * we need to enable the module functions as well as update the
+		 * reference counts for those function records.
+		 */
+		if (ftrace_start_up)
+			cnt += referenced_filters(rec);
+
+		rec->flags &= ~FTRACE_FL_DISABLED;
+		rec->flags += cnt;
+
+		if (ftrace_start_up && cnt) {
+			int failed = __ftrace_replace_code(rec, 1);
+			if (failed) {
+				ftrace_bug(failed, rec);
+				goto out_loop;
+			}
+		}
+
+	} while_for_each_ftrace_rec();
+
+ out_loop:
+	if (ftrace_start_up)
+		ftrace_arch_code_modify_post_process();
+
+ out_unlock:
+	mutex_unlock(&ftrace_lock);
+
+	process_cached_mods(mod->name);
+}
+
+void ftrace_module_init(struct module *mod)
+{
+	int ret;
+
+	if (ftrace_disabled || !mod->num_ftrace_callsites)
+		return;
+
+	ret = ftrace_process_locs(mod, mod->ftrace_callsites,
+				  mod->ftrace_callsites + mod->num_ftrace_callsites);
+	if (ret)
+		pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
+			mod->name);
+}
+
+static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
+				struct dyn_ftrace *rec)
+{
+	struct ftrace_mod_func *mod_func;
+	unsigned long symsize;
+	unsigned long offset;
+	char str[KSYM_SYMBOL_LEN];
+	char *modname;
+	const char *ret;
+
+	ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
+	if (!ret)
+		return;
+
+	mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
+	if (!mod_func)
+		return;
+
+	mod_func->name = kstrdup(str, GFP_KERNEL);
+	if (!mod_func->name) {
+		kfree(mod_func);
+		return;
+	}
+
+	mod_func->ip = rec->ip - offset;
+	mod_func->size = symsize;
+
+	mod_map->num_funcs++;
+
+	list_add_rcu(&mod_func->list, &mod_map->funcs);
+}
+
+static struct ftrace_mod_map *
+allocate_ftrace_mod_map(struct module *mod,
+			unsigned long start, unsigned long end)
+{
+	struct ftrace_mod_map *mod_map;
+
+	mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
+	if (!mod_map)
+		return NULL;
+
+	mod_map->mod = mod;
+	mod_map->start_addr = start;
+	mod_map->end_addr = end;
+	mod_map->num_funcs = 0;
+
+	INIT_LIST_HEAD_RCU(&mod_map->funcs);
+
+	list_add_rcu(&mod_map->list, &ftrace_mod_maps);
+
+	return mod_map;
+}
+
+static const char *
+ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
+			   unsigned long addr, unsigned long *size,
+			   unsigned long *off, char *sym)
+{
+	struct ftrace_mod_func *found_func =  NULL;
+	struct ftrace_mod_func *mod_func;
+
+	list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
+		if (addr >= mod_func->ip &&
+		    addr < mod_func->ip + mod_func->size) {
+			found_func = mod_func;
+			break;
+		}
+	}
+
+	if (found_func) {
+		if (size)
+			*size = found_func->size;
+		if (off)
+			*off = addr - found_func->ip;
+		if (sym)
+			strlcpy(sym, found_func->name, KSYM_NAME_LEN);
+
+		return found_func->name;
+	}
+
+	return NULL;
+}
+
+const char *
+ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
+		   unsigned long *off, char **modname, char *sym)
+{
+	struct ftrace_mod_map *mod_map;
+	const char *ret = NULL;
+
+	/* mod_map is freed via call_rcu() */
+	preempt_disable();
+	list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
+		ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
+		if (ret) {
+			if (modname)
+				*modname = mod_map->mod->name;
+			break;
+		}
+	}
+	preempt_enable();
+
+	return ret;
+}
+
+int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
+			   char *type, char *name,
+			   char *module_name, int *exported)
+{
+	struct ftrace_mod_map *mod_map;
+	struct ftrace_mod_func *mod_func;
+	int ret;
+
+	preempt_disable();
+	list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
+
+		if (symnum >= mod_map->num_funcs) {
+			symnum -= mod_map->num_funcs;
+			continue;
+		}
+
+		list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
+			if (symnum > 1) {
+				symnum--;
+				continue;
+			}
+
+			*value = mod_func->ip;
+			*type = 'T';
+			strlcpy(name, mod_func->name, KSYM_NAME_LEN);
+			strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
+			*exported = 1;
+			preempt_enable();
+			return 0;
+		}
+		WARN_ON(1);
+		break;
+	}
+	ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
+					    module_name, exported);
+	preempt_enable();
+	return ret;
+}
+
+#else
+static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
+				struct dyn_ftrace *rec) { }
+static inline struct ftrace_mod_map *
+allocate_ftrace_mod_map(struct module *mod,
+			unsigned long start, unsigned long end)
+{
+	return NULL;
+}
+int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
+			   char *type, char *name, char *module_name,
+			   int *exported)
+{
+	int ret;
+
+	preempt_disable();
+	ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
+					    module_name, exported);
+	preempt_enable();
+	return ret;
+}
+#endif /* CONFIG_MODULES */
+
+struct ftrace_init_func {
+	struct list_head list;
+	unsigned long ip;
+};
+
+/* Clear any init ips from hashes */
+static void
+clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
+{
+	struct ftrace_func_entry *entry;
+
+	entry = ftrace_lookup_ip(hash, func->ip);
+	/*
+	 * Do not allow this rec to match again.
+	 * Yeah, it may waste some memory, but will be removed
+	 * if/when the hash is modified again.
+	 */
+	if (entry)
+		entry->ip = 0;
+}
+
+static void
+clear_func_from_hashes(struct ftrace_init_func *func)
+{
+	struct trace_array *tr;
+
+	mutex_lock(&trace_types_lock);
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (!tr->ops || !tr->ops->func_hash)
+			continue;
+		mutex_lock(&tr->ops->func_hash->regex_lock);
+		clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
+		clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
+		mutex_unlock(&tr->ops->func_hash->regex_lock);
+	}
+	mutex_unlock(&trace_types_lock);
+}
+
+static void add_to_clear_hash_list(struct list_head *clear_list,
+				   struct dyn_ftrace *rec)
+{
+	struct ftrace_init_func *func;
+
+	func = kmalloc(sizeof(*func), GFP_KERNEL);
+	if (!func) {
+		MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
+		return;
+	}
+
+	func->ip = rec->ip;
+	list_add(&func->list, clear_list);
+}
+
+void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
+{
+	unsigned long start = (unsigned long)(start_ptr);
+	unsigned long end = (unsigned long)(end_ptr);
+	struct ftrace_page **last_pg = &ftrace_pages_start;
+	struct ftrace_page *pg;
+	struct dyn_ftrace *rec;
+	struct dyn_ftrace key;
+	struct ftrace_mod_map *mod_map = NULL;
+	struct ftrace_init_func *func, *func_next;
+	struct list_head clear_hash;
+
+	INIT_LIST_HEAD(&clear_hash);
+
+	key.ip = start;
+	key.flags = end;	/* overload flags, as it is unsigned long */
+
+	mutex_lock(&ftrace_lock);
+
+	/*
+	 * If we are freeing module init memory, then check if
+	 * any tracer is active. If so, we need to save a mapping of
+	 * the module functions being freed with the address.
+	 */
+	if (mod && ftrace_ops_list != &ftrace_list_end)
+		mod_map = allocate_ftrace_mod_map(mod, start, end);
+
+	for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
+		if (end < pg->records[0].ip ||
+		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
+			continue;
+ again:
+		rec = bsearch(&key, pg->records, pg->index,
+			      sizeof(struct dyn_ftrace),
+			      ftrace_cmp_recs);
+		if (!rec)
+			continue;
+
+		/* rec will be cleared from hashes after ftrace_lock unlock */
+		add_to_clear_hash_list(&clear_hash, rec);
+
+		if (mod_map)
+			save_ftrace_mod_rec(mod_map, rec);
+
+		pg->index--;
+		ftrace_update_tot_cnt--;
+		if (!pg->index) {
+			*last_pg = pg->next;
+			if (pg->records) {
+				free_pages((unsigned long)pg->records, pg->order);
+				ftrace_number_of_pages -= 1 << pg->order;
+			}
+			ftrace_number_of_groups--;
+			kfree(pg);
+			pg = container_of(last_pg, struct ftrace_page, next);
+			if (!(*last_pg))
+				ftrace_pages = pg;
+			continue;
+		}
+		memmove(rec, rec + 1,
+			(pg->index - (rec - pg->records)) * sizeof(*rec));
+		/* More than one function may be in this block */
+		goto again;
+	}
+	mutex_unlock(&ftrace_lock);
+
+	list_for_each_entry_safe(func, func_next, &clear_hash, list) {
+		clear_func_from_hashes(func);
+		kfree(func);
+	}
+}
+
+void __init ftrace_free_init_mem(void)
+{
+	void *start = (void *)(&__init_begin);
+	void *end = (void *)(&__init_end);
+
+	ftrace_boot_snapshot();
+
+	ftrace_free_mem(NULL, start, end);
+}
+
+int __init __weak ftrace_dyn_arch_init(void)
+{
+	return 0;
+}
+
+void __init ftrace_init(void)
+{
+	extern unsigned long __start_mcount_loc[];
+	extern unsigned long __stop_mcount_loc[];
+	unsigned long count, flags;
+	int ret;
+
+	local_irq_save(flags);
+	ret = ftrace_dyn_arch_init();
+	local_irq_restore(flags);
+	if (ret)
+		goto failed;
+
+	count = __stop_mcount_loc - __start_mcount_loc;
+	if (!count) {
+		pr_info("ftrace: No functions to be traced?\n");
+		goto failed;
+	}
+
+	pr_info("ftrace: allocating %ld entries in %ld pages\n",
+		count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
+
+	ret = ftrace_process_locs(NULL,
+				  __start_mcount_loc,
+				  __stop_mcount_loc);
+	if (ret) {
+		pr_warn("ftrace: failed to allocate entries for functions\n");
+		goto failed;
+	}
+
+	pr_info("ftrace: allocated %ld pages with %ld groups\n",
+		ftrace_number_of_pages, ftrace_number_of_groups);
+
+	last_ftrace_enabled = ftrace_enabled = 1;
+
+	set_ftrace_early_filters();
+
+	return;
+ failed:
+	ftrace_disabled = 1;
+}
+
+/* Do nothing if arch does not support this */
+void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
+{
+}
+
+static void ftrace_update_trampoline(struct ftrace_ops *ops)
+{
+	unsigned long trampoline = ops->trampoline;
+
+	arch_ftrace_update_trampoline(ops);
+	if (ops->trampoline && ops->trampoline != trampoline &&
+	    (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
+		/* Add to kallsyms before the perf events */
+		ftrace_add_trampoline_to_kallsyms(ops);
+		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
+				   ops->trampoline, ops->trampoline_size, false,
+				   FTRACE_TRAMPOLINE_SYM);
+		/*
+		 * Record the perf text poke event after the ksymbol register
+		 * event.
+		 */
+		perf_event_text_poke((void *)ops->trampoline, NULL, 0,
+				     (void *)ops->trampoline,
+				     ops->trampoline_size);
+	}
+}
+
+void ftrace_init_trace_array(struct trace_array *tr)
+{
+	INIT_LIST_HEAD(&tr->func_probes);
+	INIT_LIST_HEAD(&tr->mod_trace);
+	INIT_LIST_HEAD(&tr->mod_notrace);
+}
+#else
+
+struct ftrace_ops global_ops = {
+	.func			= ftrace_stub,
+	.flags			= FTRACE_OPS_FL_INITIALIZED |
+				  FTRACE_OPS_FL_PID,
+};
+
+static int __init ftrace_nodyn_init(void)
+{
+	ftrace_enabled = 1;
+	return 0;
+}
+core_initcall(ftrace_nodyn_init);
+
+static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
+static inline void ftrace_startup_all(int command) { }
+
+static void ftrace_update_trampoline(struct ftrace_ops *ops)
+{
+}
+
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+__init void ftrace_init_global_array_ops(struct trace_array *tr)
+{
+	tr->ops = &global_ops;
+	tr->ops->private = tr;
+	ftrace_init_trace_array(tr);
+}
+
+void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
+{
+	/* If we filter on pids, update to use the pid function */
+	if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
+		if (WARN_ON(tr->ops->func != ftrace_stub))
+			printk("ftrace ops had %pS for function\n",
+			       tr->ops->func);
+	}
+	tr->ops->func = func;
+	tr->ops->private = tr;
+}
+
+void ftrace_reset_array_ops(struct trace_array *tr)
+{
+	tr->ops->func = ftrace_stub;
+}
+
+static nokprobe_inline void
+__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
+		       struct ftrace_ops *ignored, struct ftrace_regs *fregs)
+{
+	struct pt_regs *regs = ftrace_get_regs(fregs);
+	struct ftrace_ops *op;
+	int bit;
+
+	/*
+	 * The ftrace_test_and_set_recursion() will disable preemption,
+	 * which is required since some of the ops may be dynamically
+	 * allocated, they must be freed after a synchronize_rcu().
+	 */
+	bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
+	if (bit < 0)
+		return;
+
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		/* Stub functions don't need to be called nor tested */
+		if (op->flags & FTRACE_OPS_FL_STUB)
+			continue;
+		/*
+		 * Check the following for each ops before calling their func:
+		 *  if RCU flag is set, then rcu_is_watching() must be true
+		 *  if PER_CPU is set, then ftrace_function_local_disable()
+		 *                          must be false
+		 *  Otherwise test if the ip matches the ops filter
+		 *
+		 * If any of the above fails then the op->func() is not executed.
+		 */
+		if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
+		    ftrace_ops_test(op, ip, regs)) {
+			if (FTRACE_WARN_ON(!op->func)) {
+				pr_warn("op=%p %pS\n", op, op);
+				goto out;
+			}
+			op->func(ip, parent_ip, op, fregs);
+		}
+	} while_for_each_ftrace_op(op);
+out:
+	trace_clear_recursion(bit);
+}
+
+/*
+ * Some archs only support passing ip and parent_ip. Even though
+ * the list function ignores the op parameter, we do not want any
+ * C side effects, where a function is called without the caller
+ * sending a third parameter.
+ * Archs are to support both the regs and ftrace_ops at the same time.
+ * If they support ftrace_ops, it is assumed they support regs.
+ * If call backs want to use regs, they must either check for regs
+ * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
+ * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
+ * An architecture can pass partial regs with ftrace_ops and still
+ * set the ARCH_SUPPORTS_FTRACE_OPS.
+ *
+ * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
+ * arch_ftrace_ops_list_func.
+ */
+#if ARCH_SUPPORTS_FTRACE_OPS
+void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
+			       struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	__ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
+}
+#else
+void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
+{
+	__ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
+}
+#endif
+NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
+
+/*
+ * If there's only one function registered but it does not support
+ * recursion, needs RCU protection and/or requires per cpu handling, then
+ * this function will be called by the mcount trampoline.
+ */
+static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
+				   struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	int bit;
+
+	bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
+	if (bit < 0)
+		return;
+
+	if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
+		op->func(ip, parent_ip, op, fregs);
+
+	trace_clear_recursion(bit);
+}
+NOKPROBE_SYMBOL(ftrace_ops_assist_func);
+
+/**
+ * ftrace_ops_get_func - get the function a trampoline should call
+ * @ops: the ops to get the function for
+ *
+ * Normally the mcount trampoline will call the ops->func, but there
+ * are times that it should not. For example, if the ops does not
+ * have its own recursion protection, then it should call the
+ * ftrace_ops_assist_func() instead.
+ *
+ * Returns the function that the trampoline should call for @ops.
+ */
+ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
+{
+	/*
+	 * If the function does not handle recursion or needs to be RCU safe,
+	 * then we need to call the assist handler.
+	 */
+	if (ops->flags & (FTRACE_OPS_FL_RECURSION |
+			  FTRACE_OPS_FL_RCU))
+		return ftrace_ops_assist_func;
+
+	return ops->func;
+}
+
+static void
+ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
+				     struct task_struct *prev,
+				     struct task_struct *next,
+				     unsigned int prev_state)
+{
+	struct trace_array *tr = data;
+	struct trace_pid_list *pid_list;
+	struct trace_pid_list *no_pid_list;
+
+	pid_list = rcu_dereference_sched(tr->function_pids);
+	no_pid_list = rcu_dereference_sched(tr->function_no_pids);
+
+	if (trace_ignore_this_task(pid_list, no_pid_list, next))
+		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
+			       FTRACE_PID_IGNORE);
+	else
+		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
+			       next->pid);
+}
+
+static void
+ftrace_pid_follow_sched_process_fork(void *data,
+				     struct task_struct *self,
+				     struct task_struct *task)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_array *tr = data;
+
+	pid_list = rcu_dereference_sched(tr->function_pids);
+	trace_filter_add_remove_task(pid_list, self, task);
+
+	pid_list = rcu_dereference_sched(tr->function_no_pids);
+	trace_filter_add_remove_task(pid_list, self, task);
+}
+
+static void
+ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_array *tr = data;
+
+	pid_list = rcu_dereference_sched(tr->function_pids);
+	trace_filter_add_remove_task(pid_list, NULL, task);
+
+	pid_list = rcu_dereference_sched(tr->function_no_pids);
+	trace_filter_add_remove_task(pid_list, NULL, task);
+}
+
+void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
+{
+	if (enable) {
+		register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
+						  tr);
+		register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
+						  tr);
+	} else {
+		unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
+						    tr);
+		unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
+						    tr);
+	}
+}
+
+static void clear_ftrace_pids(struct trace_array *tr, int type)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_pid_list *no_pid_list;
+	int cpu;
+
+	pid_list = rcu_dereference_protected(tr->function_pids,
+					     lockdep_is_held(&ftrace_lock));
+	no_pid_list = rcu_dereference_protected(tr->function_no_pids,
+						lockdep_is_held(&ftrace_lock));
+
+	/* Make sure there's something to do */
+	if (!pid_type_enabled(type, pid_list, no_pid_list))
+		return;
+
+	/* See if the pids still need to be checked after this */
+	if (!still_need_pid_events(type, pid_list, no_pid_list)) {
+		unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
+		for_each_possible_cpu(cpu)
+			per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
+	}
+
+	if (type & TRACE_PIDS)
+		rcu_assign_pointer(tr->function_pids, NULL);
+
+	if (type & TRACE_NO_PIDS)
+		rcu_assign_pointer(tr->function_no_pids, NULL);
+
+	/* Wait till all users are no longer using pid filtering */
+	synchronize_rcu();
+
+	if ((type & TRACE_PIDS) && pid_list)
+		trace_pid_list_free(pid_list);
+
+	if ((type & TRACE_NO_PIDS) && no_pid_list)
+		trace_pid_list_free(no_pid_list);
+}
+
+void ftrace_clear_pids(struct trace_array *tr)
+{
+	mutex_lock(&ftrace_lock);
+
+	clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
+
+	mutex_unlock(&ftrace_lock);
+}
+
+static void ftrace_pid_reset(struct trace_array *tr, int type)
+{
+	mutex_lock(&ftrace_lock);
+	clear_ftrace_pids(tr, type);
+
+	ftrace_update_pid_func();
+	ftrace_startup_all(0);
+
+	mutex_unlock(&ftrace_lock);
+}
+
+/* Greater than any max PID */
+#define FTRACE_NO_PIDS		(void *)(PID_MAX_LIMIT + 1)
+
+static void *fpid_start(struct seq_file *m, loff_t *pos)
+	__acquires(RCU)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_array *tr = m->private;
+
+	mutex_lock(&ftrace_lock);
+	rcu_read_lock_sched();
+
+	pid_list = rcu_dereference_sched(tr->function_pids);
+
+	if (!pid_list)
+		return !(*pos) ? FTRACE_NO_PIDS : NULL;
+
+	return trace_pid_start(pid_list, pos);
+}
+
+static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct trace_array *tr = m->private;
+	struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
+
+	if (v == FTRACE_NO_PIDS) {
+		(*pos)++;
+		return NULL;
+	}
+	return trace_pid_next(pid_list, v, pos);
+}
+
+static void fpid_stop(struct seq_file *m, void *p)
+	__releases(RCU)
+{
+	rcu_read_unlock_sched();
+	mutex_unlock(&ftrace_lock);
+}
+
+static int fpid_show(struct seq_file *m, void *v)
+{
+	if (v == FTRACE_NO_PIDS) {
+		seq_puts(m, "no pid\n");
+		return 0;
+	}
+
+	return trace_pid_show(m, v);
+}
+
+static const struct seq_operations ftrace_pid_sops = {
+	.start = fpid_start,
+	.next = fpid_next,
+	.stop = fpid_stop,
+	.show = fpid_show,
+};
+
+static void *fnpid_start(struct seq_file *m, loff_t *pos)
+	__acquires(RCU)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_array *tr = m->private;
+
+	mutex_lock(&ftrace_lock);
+	rcu_read_lock_sched();
+
+	pid_list = rcu_dereference_sched(tr->function_no_pids);
+
+	if (!pid_list)
+		return !(*pos) ? FTRACE_NO_PIDS : NULL;
+
+	return trace_pid_start(pid_list, pos);
+}
+
+static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct trace_array *tr = m->private;
+	struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
+
+	if (v == FTRACE_NO_PIDS) {
+		(*pos)++;
+		return NULL;
+	}
+	return trace_pid_next(pid_list, v, pos);
+}
+
+static const struct seq_operations ftrace_no_pid_sops = {
+	.start = fnpid_start,
+	.next = fnpid_next,
+	.stop = fpid_stop,
+	.show = fpid_show,
+};
+
+static int pid_open(struct inode *inode, struct file *file, int type)
+{
+	const struct seq_operations *seq_ops;
+	struct trace_array *tr = inode->i_private;
+	struct seq_file *m;
+	int ret = 0;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	if ((file->f_mode & FMODE_WRITE) &&
+	    (file->f_flags & O_TRUNC))
+		ftrace_pid_reset(tr, type);
+
+	switch (type) {
+	case TRACE_PIDS:
+		seq_ops = &ftrace_pid_sops;
+		break;
+	case TRACE_NO_PIDS:
+		seq_ops = &ftrace_no_pid_sops;
+		break;
+	default:
+		trace_array_put(tr);
+		WARN_ON_ONCE(1);
+		return -EINVAL;
+	}
+
+	ret = seq_open(file, seq_ops);
+	if (ret < 0) {
+		trace_array_put(tr);
+	} else {
+		m = file->private_data;
+		/* copy tr over to seq ops */
+		m->private = tr;
+	}
+
+	return ret;
+}
+
+static int
+ftrace_pid_open(struct inode *inode, struct file *file)
+{
+	return pid_open(inode, file, TRACE_PIDS);
+}
+
+static int
+ftrace_no_pid_open(struct inode *inode, struct file *file)
+{
+	return pid_open(inode, file, TRACE_NO_PIDS);
+}
+
+static void ignore_task_cpu(void *data)
+{
+	struct trace_array *tr = data;
+	struct trace_pid_list *pid_list;
+	struct trace_pid_list *no_pid_list;
+
+	/*
+	 * This function is called by on_each_cpu() while the
+	 * event_mutex is held.
+	 */
+	pid_list = rcu_dereference_protected(tr->function_pids,
+					     mutex_is_locked(&ftrace_lock));
+	no_pid_list = rcu_dereference_protected(tr->function_no_pids,
+						mutex_is_locked(&ftrace_lock));
+
+	if (trace_ignore_this_task(pid_list, no_pid_list, current))
+		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
+			       FTRACE_PID_IGNORE);
+	else
+		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
+			       current->pid);
+}
+
+static ssize_t
+pid_write(struct file *filp, const char __user *ubuf,
+	  size_t cnt, loff_t *ppos, int type)
+{
+	struct seq_file *m = filp->private_data;
+	struct trace_array *tr = m->private;
+	struct trace_pid_list *filtered_pids;
+	struct trace_pid_list *other_pids;
+	struct trace_pid_list *pid_list;
+	ssize_t ret;
+
+	if (!cnt)
+		return 0;
+
+	mutex_lock(&ftrace_lock);
+
+	switch (type) {
+	case TRACE_PIDS:
+		filtered_pids = rcu_dereference_protected(tr->function_pids,
+					     lockdep_is_held(&ftrace_lock));
+		other_pids = rcu_dereference_protected(tr->function_no_pids,
+					     lockdep_is_held(&ftrace_lock));
+		break;
+	case TRACE_NO_PIDS:
+		filtered_pids = rcu_dereference_protected(tr->function_no_pids,
+					     lockdep_is_held(&ftrace_lock));
+		other_pids = rcu_dereference_protected(tr->function_pids,
+					     lockdep_is_held(&ftrace_lock));
+		break;
+	default:
+		ret = -EINVAL;
+		WARN_ON_ONCE(1);
+		goto out;
+	}
+
+	ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
+	if (ret < 0)
+		goto out;
+
+	switch (type) {
+	case TRACE_PIDS:
+		rcu_assign_pointer(tr->function_pids, pid_list);
+		break;
+	case TRACE_NO_PIDS:
+		rcu_assign_pointer(tr->function_no_pids, pid_list);
+		break;
+	}
+
+
+	if (filtered_pids) {
+		synchronize_rcu();
+		trace_pid_list_free(filtered_pids);
+	} else if (pid_list && !other_pids) {
+		/* Register a probe to set whether to ignore the tracing of a task */
+		register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
+	}
+
+	/*
+	 * Ignoring of pids is done at task switch. But we have to
+	 * check for those tasks that are currently running.
+	 * Always do this in case a pid was appended or removed.
+	 */
+	on_each_cpu(ignore_task_cpu, tr, 1);
+
+	ftrace_update_pid_func();
+	ftrace_startup_all(0);
+ out:
+	mutex_unlock(&ftrace_lock);
+
+	if (ret > 0)
+		*ppos += ret;
+
+	return ret;
+}
+
+static ssize_t
+ftrace_pid_write(struct file *filp, const char __user *ubuf,
+		 size_t cnt, loff_t *ppos)
+{
+	return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
+}
+
+static ssize_t
+ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
+		    size_t cnt, loff_t *ppos)
+{
+	return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
+}
+
+static int
+ftrace_pid_release(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+
+	trace_array_put(tr);
+
+	return seq_release(inode, file);
+}
+
+static const struct file_operations ftrace_pid_fops = {
+	.open		= ftrace_pid_open,
+	.write		= ftrace_pid_write,
+	.read		= seq_read,
+	.llseek		= tracing_lseek,
+	.release	= ftrace_pid_release,
+};
+
+static const struct file_operations ftrace_no_pid_fops = {
+	.open		= ftrace_no_pid_open,
+	.write		= ftrace_no_pid_write,
+	.read		= seq_read,
+	.llseek		= tracing_lseek,
+	.release	= ftrace_pid_release,
+};
+
+void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
+{
+	trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
+			    tr, &ftrace_pid_fops);
+	trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
+			  d_tracer, tr, &ftrace_no_pid_fops);
+}
+
+void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
+					 struct dentry *d_tracer)
+{
+	/* Only the top level directory has the dyn_tracefs and profile */
+	WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
+
+	ftrace_init_dyn_tracefs(d_tracer);
+	ftrace_profile_tracefs(d_tracer);
+}
+
+/**
+ * ftrace_kill - kill ftrace
+ *
+ * This function should be used by panic code. It stops ftrace
+ * but in a not so nice way. If you need to simply kill ftrace
+ * from a non-atomic section, use ftrace_kill.
+ */
+void ftrace_kill(void)
+{
+	ftrace_disabled = 1;
+	ftrace_enabled = 0;
+	ftrace_trace_function = ftrace_stub;
+}
+
+/**
+ * ftrace_is_dead - Test if ftrace is dead or not.
+ *
+ * Returns 1 if ftrace is "dead", zero otherwise.
+ */
+int ftrace_is_dead(void)
+{
+	return ftrace_disabled;
+}
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+/*
+ * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
+ * it doesn't conflict with any direct ftrace_ops. If there is existing
+ * direct ftrace_ops on a kernel function being patched, call
+ * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
+ *
+ * @ops:     ftrace_ops being registered.
+ *
+ * Returns:
+ *         0 on success;
+ *         Negative on failure.
+ */
+static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
+{
+	struct ftrace_func_entry *entry;
+	struct ftrace_hash *hash;
+	struct ftrace_ops *op;
+	int size, i, ret;
+
+	lockdep_assert_held_once(&direct_mutex);
+
+	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
+		return 0;
+
+	hash = ops->func_hash->filter_hash;
+	size = 1 << hash->size_bits;
+	for (i = 0; i < size; i++) {
+		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
+			unsigned long ip = entry->ip;
+			bool found_op = false;
+
+			mutex_lock(&ftrace_lock);
+			do_for_each_ftrace_op(op, ftrace_ops_list) {
+				if (!(op->flags & FTRACE_OPS_FL_DIRECT))
+					continue;
+				if (ops_references_ip(op, ip)) {
+					found_op = true;
+					break;
+				}
+			} while_for_each_ftrace_op(op);
+			mutex_unlock(&ftrace_lock);
+
+			if (found_op) {
+				if (!op->ops_func)
+					return -EBUSY;
+
+				ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
+				if (ret)
+					return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
+ * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
+ * ops.
+ */
+static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
+{
+	struct ftrace_func_entry *entry;
+	struct ftrace_hash *hash;
+	struct ftrace_ops *op;
+	int size, i;
+
+	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
+		return;
+
+	mutex_lock(&direct_mutex);
+
+	hash = ops->func_hash->filter_hash;
+	size = 1 << hash->size_bits;
+	for (i = 0; i < size; i++) {
+		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
+			unsigned long ip = entry->ip;
+			bool found_op = false;
+
+			mutex_lock(&ftrace_lock);
+			do_for_each_ftrace_op(op, ftrace_ops_list) {
+				if (!(op->flags & FTRACE_OPS_FL_DIRECT))
+					continue;
+				if (ops_references_ip(op, ip)) {
+					found_op = true;
+					break;
+				}
+			} while_for_each_ftrace_op(op);
+			mutex_unlock(&ftrace_lock);
+
+			/* The cleanup is optional, ignore any errors */
+			if (found_op && op->ops_func)
+				op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
+		}
+	}
+	mutex_unlock(&direct_mutex);
+}
+
+#define lock_direct_mutex()	mutex_lock(&direct_mutex)
+#define unlock_direct_mutex()	mutex_unlock(&direct_mutex)
+
+#else  /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
+
+static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
+{
+	return 0;
+}
+
+static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
+{
+}
+
+#define lock_direct_mutex()	do { } while (0)
+#define unlock_direct_mutex()	do { } while (0)
+
+#endif  /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
+
+/*
+ * Similar to register_ftrace_function, except we don't lock direct_mutex.
+ */
+static int register_ftrace_function_nolock(struct ftrace_ops *ops)
+{
+	int ret;
+
+	ftrace_ops_init(ops);
+
+	mutex_lock(&ftrace_lock);
+
+	ret = ftrace_startup(ops, 0);
+
+	mutex_unlock(&ftrace_lock);
+
+	return ret;
+}
+
+/**
+ * register_ftrace_function - register a function for profiling
+ * @ops:	ops structure that holds the function for profiling.
+ *
+ * Register a function to be called by all functions in the
+ * kernel.
+ *
+ * Note: @ops->func and all the functions it calls must be labeled
+ *       with "notrace", otherwise it will go into a
+ *       recursive loop.
+ */
+int register_ftrace_function(struct ftrace_ops *ops)
+{
+	int ret;
+
+	lock_direct_mutex();
+	ret = prepare_direct_functions_for_ipmodify(ops);
+	if (ret < 0)
+		goto out_unlock;
+
+	ret = register_ftrace_function_nolock(ops);
+
+out_unlock:
+	unlock_direct_mutex();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_ftrace_function);
+
+/**
+ * unregister_ftrace_function - unregister a function for profiling.
+ * @ops:	ops structure that holds the function to unregister
+ *
+ * Unregister a function that was added to be called by ftrace profiling.
+ */
+int unregister_ftrace_function(struct ftrace_ops *ops)
+{
+	int ret;
+
+	mutex_lock(&ftrace_lock);
+	ret = ftrace_shutdown(ops, 0);
+	mutex_unlock(&ftrace_lock);
+
+	cleanup_direct_functions_after_ipmodify(ops);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(unregister_ftrace_function);
+
+static int symbols_cmp(const void *a, const void *b)
+{
+	const char **str_a = (const char **) a;
+	const char **str_b = (const char **) b;
+
+	return strcmp(*str_a, *str_b);
+}
+
+struct kallsyms_data {
+	unsigned long *addrs;
+	const char **syms;
+	size_t cnt;
+	size_t found;
+};
+
+static int kallsyms_callback(void *data, const char *name,
+			     struct module *mod, unsigned long addr)
+{
+	struct kallsyms_data *args = data;
+	const char **sym;
+	int idx;
+
+	sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
+	if (!sym)
+		return 0;
+
+	idx = sym - args->syms;
+	if (args->addrs[idx])
+		return 0;
+
+	if (!ftrace_location(addr))
+		return 0;
+
+	args->addrs[idx] = addr;
+	args->found++;
+	return args->found == args->cnt ? 1 : 0;
+}
+
+/**
+ * ftrace_lookup_symbols - Lookup addresses for array of symbols
+ *
+ * @sorted_syms: array of symbols pointers symbols to resolve,
+ * must be alphabetically sorted
+ * @cnt: number of symbols/addresses in @syms/@addrs arrays
+ * @addrs: array for storing resulting addresses
+ *
+ * This function looks up addresses for array of symbols provided in
+ * @syms array (must be alphabetically sorted) and stores them in
+ * @addrs array, which needs to be big enough to store at least @cnt
+ * addresses.
+ *
+ * This function returns 0 if all provided symbols are found,
+ * -ESRCH otherwise.
+ */
+int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
+{
+	struct kallsyms_data args;
+	int err;
+
+	memset(addrs, 0, sizeof(*addrs) * cnt);
+	args.addrs = addrs;
+	args.syms = sorted_syms;
+	args.cnt = cnt;
+	args.found = 0;
+	err = kallsyms_on_each_symbol(kallsyms_callback, &args);
+	if (err < 0)
+		return err;
+	return args.found == args.cnt ? 0 : -ESRCH;
+}
+
+#ifdef CONFIG_SYSCTL
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+static void ftrace_startup_sysctl(void)
+{
+	int command;
+
+	if (unlikely(ftrace_disabled))
+		return;
+
+	/* Force update next time */
+	saved_ftrace_func = NULL;
+	/* ftrace_start_up is true if we want ftrace running */
+	if (ftrace_start_up) {
+		command = FTRACE_UPDATE_CALLS;
+		if (ftrace_graph_active)
+			command |= FTRACE_START_FUNC_RET;
+		ftrace_startup_enable(command);
+	}
+}
+
+static void ftrace_shutdown_sysctl(void)
+{
+	int command;
+
+	if (unlikely(ftrace_disabled))
+		return;
+
+	/* ftrace_start_up is true if ftrace is running */
+	if (ftrace_start_up) {
+		command = FTRACE_DISABLE_CALLS;
+		if (ftrace_graph_active)
+			command |= FTRACE_STOP_FUNC_RET;
+		ftrace_run_update_code(command);
+	}
+}
+#else
+# define ftrace_startup_sysctl()       do { } while (0)
+# define ftrace_shutdown_sysctl()      do { } while (0)
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+static bool is_permanent_ops_registered(void)
+{
+	struct ftrace_ops *op;
+
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		if (op->flags & FTRACE_OPS_FL_PERMANENT)
+			return true;
+	} while_for_each_ftrace_op(op);
+
+	return false;
+}
+
+static int
+ftrace_enable_sysctl(struct ctl_table *table, int write,
+		     void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int ret = -ENODEV;
+
+	mutex_lock(&ftrace_lock);
+
+	if (unlikely(ftrace_disabled))
+		goto out;
+
+	ret = proc_dointvec(table, write, buffer, lenp, ppos);
+
+	if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
+		goto out;
+
+	if (ftrace_enabled) {
+
+		/* we are starting ftrace again */
+		if (rcu_dereference_protected(ftrace_ops_list,
+			lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
+			update_ftrace_function();
+
+		ftrace_startup_sysctl();
+
+	} else {
+		if (is_permanent_ops_registered()) {
+			ftrace_enabled = true;
+			ret = -EBUSY;
+			goto out;
+		}
+
+		/* stopping ftrace calls (just send to ftrace_stub) */
+		ftrace_trace_function = ftrace_stub;
+
+		ftrace_shutdown_sysctl();
+	}
+
+	last_ftrace_enabled = !!ftrace_enabled;
+ out:
+	mutex_unlock(&ftrace_lock);
+	return ret;
+}
+
+static struct ctl_table ftrace_sysctls[] = {
+	{
+		.procname       = "ftrace_enabled",
+		.data           = &ftrace_enabled,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = ftrace_enable_sysctl,
+	},
+	{}
+};
+
+static int __init ftrace_sysctl_init(void)
+{
+	register_sysctl_init("kernel", ftrace_sysctls);
+	return 0;
+}
+late_initcall(ftrace_sysctl_init);
+#endif
diff --git a/kernel/trace/ftrace_internal.h b/kernel/trace/ftrace_internal.h
new file mode 100644
index 000000000..382775edf
--- /dev/null
+++ b/kernel/trace/ftrace_internal.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_KERNEL_FTRACE_INTERNAL_H
+#define  _LINUX_KERNEL_FTRACE_INTERNAL_H
+
+#ifdef CONFIG_FUNCTION_TRACER
+
+extern struct mutex ftrace_lock;
+extern struct ftrace_ops global_ops;
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+int ftrace_startup(struct ftrace_ops *ops, int command);
+int ftrace_shutdown(struct ftrace_ops *ops, int command);
+int ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs);
+
+#else /* !CONFIG_DYNAMIC_FTRACE */
+
+int __register_ftrace_function(struct ftrace_ops *ops);
+int __unregister_ftrace_function(struct ftrace_ops *ops);
+/* Keep as macros so we do not need to define the commands */
+# define ftrace_startup(ops, command)					\
+	({								\
+		int ___ret = __register_ftrace_function(ops);		\
+		if (!___ret)						\
+			(ops)->flags |= FTRACE_OPS_FL_ENABLED;		\
+		___ret;							\
+	})
+# define ftrace_shutdown(ops, command)					\
+	({								\
+		int ___ret = __unregister_ftrace_function(ops);		\
+		if (!___ret)						\
+			(ops)->flags &= ~FTRACE_OPS_FL_ENABLED;		\
+		___ret;							\
+	})
+static inline int
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
+{
+	return 1;
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+extern int ftrace_graph_active;
+void update_function_graph_func(void);
+#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
+# define ftrace_graph_active 0
+static inline void update_function_graph_func(void) { }
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+#else /* !CONFIG_FUNCTION_TRACER */
+#endif /* CONFIG_FUNCTION_TRACER */
+
+#endif
diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c
new file mode 100644
index 000000000..e0c420eb0
--- /dev/null
+++ b/kernel/trace/kprobe_event_gen_test.c
@@ -0,0 +1,276 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test module for in-kernel kprobe event creation and generation.
+ *
+ * Copyright (C) 2019 Tom Zanussi <zanussi@kernel.org>
+ */
+
+#include <linux/module.h>
+#include <linux/trace_events.h>
+
+/*
+ * This module is a simple test of basic functionality for in-kernel
+ * kprobe/kretprobe event creation.  The first test uses
+ * kprobe_event_gen_cmd_start(), kprobe_event_add_fields() and
+ * kprobe_event_gen_cmd_end() to create a kprobe event, which is then
+ * enabled in order to generate trace output.  The second creates a
+ * kretprobe event using kretprobe_event_gen_cmd_start() and
+ * kretprobe_event_gen_cmd_end(), and is also then enabled.
+ *
+ * To test, select CONFIG_KPROBE_EVENT_GEN_TEST and build the module.
+ * Then:
+ *
+ * # insmod kernel/trace/kprobe_event_gen_test.ko
+ * # cat /sys/kernel/debug/tracing/trace
+ *
+ * You should see many instances of the "gen_kprobe_test" and
+ * "gen_kretprobe_test" events in the trace buffer.
+ *
+ * To remove the events, remove the module:
+ *
+ * # rmmod kprobe_event_gen_test
+ *
+ */
+
+static struct trace_event_file *gen_kprobe_test;
+static struct trace_event_file *gen_kretprobe_test;
+
+#define KPROBE_GEN_TEST_FUNC	"do_sys_open"
+
+/* X86 */
+#if defined(CONFIG_X86_64) || defined(CONFIG_X86_32)
+#define KPROBE_GEN_TEST_ARG0	"dfd=%ax"
+#define KPROBE_GEN_TEST_ARG1	"filename=%dx"
+#define KPROBE_GEN_TEST_ARG2	"flags=%cx"
+#define KPROBE_GEN_TEST_ARG3	"mode=+4($stack)"
+
+/* ARM64 */
+#elif defined(CONFIG_ARM64)
+#define KPROBE_GEN_TEST_ARG0	"dfd=%x0"
+#define KPROBE_GEN_TEST_ARG1	"filename=%x1"
+#define KPROBE_GEN_TEST_ARG2	"flags=%x2"
+#define KPROBE_GEN_TEST_ARG3	"mode=%x3"
+
+/* ARM */
+#elif defined(CONFIG_ARM)
+#define KPROBE_GEN_TEST_ARG0	"dfd=%r0"
+#define KPROBE_GEN_TEST_ARG1	"filename=%r1"
+#define KPROBE_GEN_TEST_ARG2	"flags=%r2"
+#define KPROBE_GEN_TEST_ARG3	"mode=%r3"
+
+/* RISCV */
+#elif defined(CONFIG_RISCV)
+#define KPROBE_GEN_TEST_ARG0	"dfd=%a0"
+#define KPROBE_GEN_TEST_ARG1	"filename=%a1"
+#define KPROBE_GEN_TEST_ARG2	"flags=%a2"
+#define KPROBE_GEN_TEST_ARG3	"mode=%a3"
+
+/* others */
+#else
+#define KPROBE_GEN_TEST_ARG0	NULL
+#define KPROBE_GEN_TEST_ARG1	NULL
+#define KPROBE_GEN_TEST_ARG2	NULL
+#define KPROBE_GEN_TEST_ARG3	NULL
+#endif
+
+static bool trace_event_file_is_valid(struct trace_event_file *input)
+{
+	return input && !IS_ERR(input);
+}
+
+/*
+ * Test to make sure we can create a kprobe event, then add more
+ * fields.
+ */
+static int __init test_gen_kprobe_cmd(void)
+{
+	struct dynevent_cmd cmd;
+	char *buf;
+	int ret;
+
+	/* Create a buffer to hold the generated command */
+	buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	/* Before generating the command, initialize the cmd object */
+	kprobe_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
+
+	/*
+	 * Define the gen_kprobe_test event with the first 2 kprobe
+	 * fields.
+	 */
+	ret = kprobe_event_gen_cmd_start(&cmd, "gen_kprobe_test",
+					 KPROBE_GEN_TEST_FUNC,
+					 KPROBE_GEN_TEST_ARG0, KPROBE_GEN_TEST_ARG1);
+	if (ret)
+		goto out;
+
+	/* Use kprobe_event_add_fields to add the rest of the fields */
+
+	ret = kprobe_event_add_fields(&cmd, KPROBE_GEN_TEST_ARG2, KPROBE_GEN_TEST_ARG3);
+	if (ret)
+		goto out;
+
+	/*
+	 * This actually creates the event.
+	 */
+	ret = kprobe_event_gen_cmd_end(&cmd);
+	if (ret)
+		goto out;
+
+	/*
+	 * Now get the gen_kprobe_test event file.  We need to prevent
+	 * the instance and event from disappearing from underneath
+	 * us, which trace_get_event_file() does (though in this case
+	 * we're using the top-level instance which never goes away).
+	 */
+	gen_kprobe_test = trace_get_event_file(NULL, "kprobes",
+					       "gen_kprobe_test");
+	if (IS_ERR(gen_kprobe_test)) {
+		ret = PTR_ERR(gen_kprobe_test);
+		goto delete;
+	}
+
+	/* Enable the event or you won't see anything */
+	ret = trace_array_set_clr_event(gen_kprobe_test->tr,
+					"kprobes", "gen_kprobe_test", true);
+	if (ret) {
+		trace_put_event_file(gen_kprobe_test);
+		goto delete;
+	}
+ out:
+	kfree(buf);
+	return ret;
+ delete:
+	if (trace_event_file_is_valid(gen_kprobe_test))
+		gen_kprobe_test = NULL;
+	/* We got an error after creating the event, delete it */
+	kprobe_event_delete("gen_kprobe_test");
+	goto out;
+}
+
+/*
+ * Test to make sure we can create a kretprobe event.
+ */
+static int __init test_gen_kretprobe_cmd(void)
+{
+	struct dynevent_cmd cmd;
+	char *buf;
+	int ret;
+
+	/* Create a buffer to hold the generated command */
+	buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	/* Before generating the command, initialize the cmd object */
+	kprobe_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
+
+	/*
+	 * Define the kretprobe event.
+	 */
+	ret = kretprobe_event_gen_cmd_start(&cmd, "gen_kretprobe_test",
+					    KPROBE_GEN_TEST_FUNC,
+					    "$retval");
+	if (ret)
+		goto out;
+
+	/*
+	 * This actually creates the event.
+	 */
+	ret = kretprobe_event_gen_cmd_end(&cmd);
+	if (ret)
+		goto out;
+
+	/*
+	 * Now get the gen_kretprobe_test event file.  We need to
+	 * prevent the instance and event from disappearing from
+	 * underneath us, which trace_get_event_file() does (though in
+	 * this case we're using the top-level instance which never
+	 * goes away).
+	 */
+	gen_kretprobe_test = trace_get_event_file(NULL, "kprobes",
+						  "gen_kretprobe_test");
+	if (IS_ERR(gen_kretprobe_test)) {
+		ret = PTR_ERR(gen_kretprobe_test);
+		goto delete;
+	}
+
+	/* Enable the event or you won't see anything */
+	ret = trace_array_set_clr_event(gen_kretprobe_test->tr,
+					"kprobes", "gen_kretprobe_test", true);
+	if (ret) {
+		trace_put_event_file(gen_kretprobe_test);
+		goto delete;
+	}
+ out:
+	kfree(buf);
+	return ret;
+ delete:
+	if (trace_event_file_is_valid(gen_kretprobe_test))
+		gen_kretprobe_test = NULL;
+	/* We got an error after creating the event, delete it */
+	kprobe_event_delete("gen_kretprobe_test");
+	goto out;
+}
+
+static int __init kprobe_event_gen_test_init(void)
+{
+	int ret;
+
+	ret = test_gen_kprobe_cmd();
+	if (ret)
+		return ret;
+
+	ret = test_gen_kretprobe_cmd();
+	if (ret) {
+		if (trace_event_file_is_valid(gen_kretprobe_test)) {
+			WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
+							  "kprobes",
+							  "gen_kretprobe_test", false));
+			trace_put_event_file(gen_kretprobe_test);
+		}
+		WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
+	}
+
+	return ret;
+}
+
+static void __exit kprobe_event_gen_test_exit(void)
+{
+	if (trace_event_file_is_valid(gen_kprobe_test)) {
+		/* Disable the event or you can't remove it */
+		WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
+						  "kprobes",
+						  "gen_kprobe_test", false));
+
+		/* Now give the file and instance back */
+		trace_put_event_file(gen_kprobe_test);
+	}
+
+
+	/* Now unregister and free the event */
+	WARN_ON(kprobe_event_delete("gen_kprobe_test"));
+
+	if (trace_event_file_is_valid(gen_kretprobe_test)) {
+		/* Disable the event or you can't remove it */
+		WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
+						  "kprobes",
+						  "gen_kretprobe_test", false));
+
+		/* Now give the file and instance back */
+		trace_put_event_file(gen_kretprobe_test);
+	}
+
+
+	/* Now unregister and free the event */
+	WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
+}
+
+module_init(kprobe_event_gen_test_init)
+module_exit(kprobe_event_gen_test_exit)
+
+MODULE_AUTHOR("Tom Zanussi");
+MODULE_DESCRIPTION("kprobe event generation test");
+MODULE_LICENSE("GPL v2");
diff --git a/kernel/trace/pid_list.c b/kernel/trace/pid_list.c
new file mode 100644
index 000000000..95106d02b
--- /dev/null
+++ b/kernel/trace/pid_list.c
@@ -0,0 +1,495 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 VMware Inc, Steven Rostedt <rostedt@goodmis.org>
+ */
+#include <linux/spinlock.h>
+#include <linux/irq_work.h>
+#include <linux/slab.h>
+#include "trace.h"
+
+/* See pid_list.h for details */
+
+static inline union lower_chunk *get_lower_chunk(struct trace_pid_list *pid_list)
+{
+	union lower_chunk *chunk;
+
+	lockdep_assert_held(&pid_list->lock);
+
+	if (!pid_list->lower_list)
+		return NULL;
+
+	chunk = pid_list->lower_list;
+	pid_list->lower_list = chunk->next;
+	pid_list->free_lower_chunks--;
+	WARN_ON_ONCE(pid_list->free_lower_chunks < 0);
+	chunk->next = NULL;
+	/*
+	 * If a refill needs to happen, it can not happen here
+	 * as the scheduler run queue locks are held.
+	 */
+	if (pid_list->free_lower_chunks <= CHUNK_REALLOC)
+		irq_work_queue(&pid_list->refill_irqwork);
+
+	return chunk;
+}
+
+static inline union upper_chunk *get_upper_chunk(struct trace_pid_list *pid_list)
+{
+	union upper_chunk *chunk;
+
+	lockdep_assert_held(&pid_list->lock);
+
+	if (!pid_list->upper_list)
+		return NULL;
+
+	chunk = pid_list->upper_list;
+	pid_list->upper_list = chunk->next;
+	pid_list->free_upper_chunks--;
+	WARN_ON_ONCE(pid_list->free_upper_chunks < 0);
+	chunk->next = NULL;
+	/*
+	 * If a refill needs to happen, it can not happen here
+	 * as the scheduler run queue locks are held.
+	 */
+	if (pid_list->free_upper_chunks <= CHUNK_REALLOC)
+		irq_work_queue(&pid_list->refill_irqwork);
+
+	return chunk;
+}
+
+static inline void put_lower_chunk(struct trace_pid_list *pid_list,
+				   union lower_chunk *chunk)
+{
+	lockdep_assert_held(&pid_list->lock);
+
+	chunk->next = pid_list->lower_list;
+	pid_list->lower_list = chunk;
+	pid_list->free_lower_chunks++;
+}
+
+static inline void put_upper_chunk(struct trace_pid_list *pid_list,
+				   union upper_chunk *chunk)
+{
+	lockdep_assert_held(&pid_list->lock);
+
+	chunk->next = pid_list->upper_list;
+	pid_list->upper_list = chunk;
+	pid_list->free_upper_chunks++;
+}
+
+static inline bool upper_empty(union upper_chunk *chunk)
+{
+	/*
+	 * If chunk->data has no lower chunks, it will be the same
+	 * as a zeroed bitmask. Use find_first_bit() to test it
+	 * and if it doesn't find any bits set, then the array
+	 * is empty.
+	 */
+	int bit = find_first_bit((unsigned long *)chunk->data,
+				 sizeof(chunk->data) * 8);
+	return bit >= sizeof(chunk->data) * 8;
+}
+
+static inline int pid_split(unsigned int pid, unsigned int *upper1,
+			     unsigned int *upper2, unsigned int *lower)
+{
+	/* MAX_PID should cover all pids */
+	BUILD_BUG_ON(MAX_PID < PID_MAX_LIMIT);
+
+	/* In case a bad pid is passed in, then fail */
+	if (unlikely(pid >= MAX_PID))
+		return -1;
+
+	*upper1 = (pid >> UPPER1_SHIFT) & UPPER_MASK;
+	*upper2 = (pid >> UPPER2_SHIFT) & UPPER_MASK;
+	*lower = pid & LOWER_MASK;
+
+	return 0;
+}
+
+static inline unsigned int pid_join(unsigned int upper1,
+				    unsigned int upper2, unsigned int lower)
+{
+	return ((upper1 & UPPER_MASK) << UPPER1_SHIFT) |
+		((upper2 & UPPER_MASK) << UPPER2_SHIFT) |
+		(lower & LOWER_MASK);
+}
+
+/**
+ * trace_pid_list_is_set - test if the pid is set in the list
+ * @pid_list: The pid list to test
+ * @pid: The pid to see if set in the list.
+ *
+ * Tests if @pid is set in the @pid_list. This is usually called
+ * from the scheduler when a task is scheduled. Its pid is checked
+ * if it should be traced or not.
+ *
+ * Return true if the pid is in the list, false otherwise.
+ */
+bool trace_pid_list_is_set(struct trace_pid_list *pid_list, unsigned int pid)
+{
+	union upper_chunk *upper_chunk;
+	union lower_chunk *lower_chunk;
+	unsigned long flags;
+	unsigned int upper1;
+	unsigned int upper2;
+	unsigned int lower;
+	bool ret = false;
+
+	if (!pid_list)
+		return false;
+
+	if (pid_split(pid, &upper1, &upper2, &lower) < 0)
+		return false;
+
+	raw_spin_lock_irqsave(&pid_list->lock, flags);
+	upper_chunk = pid_list->upper[upper1];
+	if (upper_chunk) {
+		lower_chunk = upper_chunk->data[upper2];
+		if (lower_chunk)
+			ret = test_bit(lower, lower_chunk->data);
+	}
+	raw_spin_unlock_irqrestore(&pid_list->lock, flags);
+
+	return ret;
+}
+
+/**
+ * trace_pid_list_set - add a pid to the list
+ * @pid_list: The pid list to add the @pid to.
+ * @pid: The pid to add.
+ *
+ * Adds @pid to @pid_list. This is usually done explicitly by a user
+ * adding a task to be traced, or indirectly by the fork function
+ * when children should be traced and a task's pid is in the list.
+ *
+ * Return 0 on success, negative otherwise.
+ */
+int trace_pid_list_set(struct trace_pid_list *pid_list, unsigned int pid)
+{
+	union upper_chunk *upper_chunk;
+	union lower_chunk *lower_chunk;
+	unsigned long flags;
+	unsigned int upper1;
+	unsigned int upper2;
+	unsigned int lower;
+	int ret;
+
+	if (!pid_list)
+		return -ENODEV;
+
+	if (pid_split(pid, &upper1, &upper2, &lower) < 0)
+		return -EINVAL;
+
+	raw_spin_lock_irqsave(&pid_list->lock, flags);
+	upper_chunk = pid_list->upper[upper1];
+	if (!upper_chunk) {
+		upper_chunk = get_upper_chunk(pid_list);
+		if (!upper_chunk) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		pid_list->upper[upper1] = upper_chunk;
+	}
+	lower_chunk = upper_chunk->data[upper2];
+	if (!lower_chunk) {
+		lower_chunk = get_lower_chunk(pid_list);
+		if (!lower_chunk) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		upper_chunk->data[upper2] = lower_chunk;
+	}
+	set_bit(lower, lower_chunk->data);
+	ret = 0;
+ out:
+	raw_spin_unlock_irqrestore(&pid_list->lock, flags);
+	return ret;
+}
+
+/**
+ * trace_pid_list_clear - remove a pid from the list
+ * @pid_list: The pid list to remove the @pid from.
+ * @pid: The pid to remove.
+ *
+ * Removes @pid from @pid_list. This is usually done explicitly by a user
+ * removing tasks from tracing, or indirectly by the exit function
+ * when a task that is set to be traced exits.
+ *
+ * Return 0 on success, negative otherwise.
+ */
+int trace_pid_list_clear(struct trace_pid_list *pid_list, unsigned int pid)
+{
+	union upper_chunk *upper_chunk;
+	union lower_chunk *lower_chunk;
+	unsigned long flags;
+	unsigned int upper1;
+	unsigned int upper2;
+	unsigned int lower;
+
+	if (!pid_list)
+		return -ENODEV;
+
+	if (pid_split(pid, &upper1, &upper2, &lower) < 0)
+		return -EINVAL;
+
+	raw_spin_lock_irqsave(&pid_list->lock, flags);
+	upper_chunk = pid_list->upper[upper1];
+	if (!upper_chunk)
+		goto out;
+
+	lower_chunk = upper_chunk->data[upper2];
+	if (!lower_chunk)
+		goto out;
+
+	clear_bit(lower, lower_chunk->data);
+
+	/* if there's no more bits set, add it to the free list */
+	if (find_first_bit(lower_chunk->data, LOWER_MAX) >= LOWER_MAX) {
+		put_lower_chunk(pid_list, lower_chunk);
+		upper_chunk->data[upper2] = NULL;
+		if (upper_empty(upper_chunk)) {
+			put_upper_chunk(pid_list, upper_chunk);
+			pid_list->upper[upper1] = NULL;
+		}
+	}
+ out:
+	raw_spin_unlock_irqrestore(&pid_list->lock, flags);
+	return 0;
+}
+
+/**
+ * trace_pid_list_next - return the next pid in the list
+ * @pid_list: The pid list to examine.
+ * @pid: The pid to start from
+ * @next: The pointer to place the pid that is set starting from @pid.
+ *
+ * Looks for the next consecutive pid that is in @pid_list starting
+ * at the pid specified by @pid. If one is set (including @pid), then
+ * that pid is placed into @next.
+ *
+ * Return 0 when a pid is found, -1 if there are no more pids included.
+ */
+int trace_pid_list_next(struct trace_pid_list *pid_list, unsigned int pid,
+			unsigned int *next)
+{
+	union upper_chunk *upper_chunk;
+	union lower_chunk *lower_chunk;
+	unsigned long flags;
+	unsigned int upper1;
+	unsigned int upper2;
+	unsigned int lower;
+
+	if (!pid_list)
+		return -ENODEV;
+
+	if (pid_split(pid, &upper1, &upper2, &lower) < 0)
+		return -EINVAL;
+
+	raw_spin_lock_irqsave(&pid_list->lock, flags);
+	for (; upper1 <= UPPER_MASK; upper1++, upper2 = 0) {
+		upper_chunk = pid_list->upper[upper1];
+
+		if (!upper_chunk)
+			continue;
+
+		for (; upper2 <= UPPER_MASK; upper2++, lower = 0) {
+			lower_chunk = upper_chunk->data[upper2];
+			if (!lower_chunk)
+				continue;
+
+			lower = find_next_bit(lower_chunk->data, LOWER_MAX,
+					    lower);
+			if (lower < LOWER_MAX)
+				goto found;
+		}
+	}
+
+ found:
+	raw_spin_unlock_irqrestore(&pid_list->lock, flags);
+	if (upper1 > UPPER_MASK)
+		return -1;
+
+	*next = pid_join(upper1, upper2, lower);
+	return 0;
+}
+
+/**
+ * trace_pid_list_first - return the first pid in the list
+ * @pid_list: The pid list to examine.
+ * @pid: The pointer to place the pid first found pid that is set.
+ *
+ * Looks for the first pid that is set in @pid_list, and places it
+ * into @pid if found.
+ *
+ * Return 0 when a pid is found, -1 if there are no pids set.
+ */
+int trace_pid_list_first(struct trace_pid_list *pid_list, unsigned int *pid)
+{
+	return trace_pid_list_next(pid_list, 0, pid);
+}
+
+static void pid_list_refill_irq(struct irq_work *iwork)
+{
+	struct trace_pid_list *pid_list = container_of(iwork, struct trace_pid_list,
+						       refill_irqwork);
+	union upper_chunk *upper = NULL;
+	union lower_chunk *lower = NULL;
+	union upper_chunk **upper_next = &upper;
+	union lower_chunk **lower_next = &lower;
+	int upper_count;
+	int lower_count;
+	int ucnt = 0;
+	int lcnt = 0;
+
+ again:
+	raw_spin_lock(&pid_list->lock);
+	upper_count = CHUNK_ALLOC - pid_list->free_upper_chunks;
+	lower_count = CHUNK_ALLOC - pid_list->free_lower_chunks;
+	raw_spin_unlock(&pid_list->lock);
+
+	if (upper_count <= 0 && lower_count <= 0)
+		return;
+
+	while (upper_count-- > 0) {
+		union upper_chunk *chunk;
+
+		chunk = kzalloc(sizeof(*chunk), GFP_KERNEL);
+		if (!chunk)
+			break;
+		*upper_next = chunk;
+		upper_next = &chunk->next;
+		ucnt++;
+	}
+
+	while (lower_count-- > 0) {
+		union lower_chunk *chunk;
+
+		chunk = kzalloc(sizeof(*chunk), GFP_KERNEL);
+		if (!chunk)
+			break;
+		*lower_next = chunk;
+		lower_next = &chunk->next;
+		lcnt++;
+	}
+
+	raw_spin_lock(&pid_list->lock);
+	if (upper) {
+		*upper_next = pid_list->upper_list;
+		pid_list->upper_list = upper;
+		pid_list->free_upper_chunks += ucnt;
+	}
+	if (lower) {
+		*lower_next = pid_list->lower_list;
+		pid_list->lower_list = lower;
+		pid_list->free_lower_chunks += lcnt;
+	}
+	raw_spin_unlock(&pid_list->lock);
+
+	/*
+	 * On success of allocating all the chunks, both counters
+	 * will be less than zero. If they are not, then an allocation
+	 * failed, and we should not try again.
+	 */
+	if (upper_count >= 0 || lower_count >= 0)
+		return;
+	/*
+	 * When the locks were released, free chunks could have
+	 * been used and allocation needs to be done again. Might as
+	 * well allocate it now.
+	 */
+	goto again;
+}
+
+/**
+ * trace_pid_list_alloc - create a new pid_list
+ *
+ * Allocates a new pid_list to store pids into.
+ *
+ * Returns the pid_list on success, NULL otherwise.
+ */
+struct trace_pid_list *trace_pid_list_alloc(void)
+{
+	struct trace_pid_list *pid_list;
+	int i;
+
+	/* According to linux/thread.h, pids can be no bigger that 30 bits */
+	WARN_ON_ONCE(pid_max > (1 << 30));
+
+	pid_list = kzalloc(sizeof(*pid_list), GFP_KERNEL);
+	if (!pid_list)
+		return NULL;
+
+	init_irq_work(&pid_list->refill_irqwork, pid_list_refill_irq);
+
+	raw_spin_lock_init(&pid_list->lock);
+
+	for (i = 0; i < CHUNK_ALLOC; i++) {
+		union upper_chunk *chunk;
+
+		chunk = kzalloc(sizeof(*chunk), GFP_KERNEL);
+		if (!chunk)
+			break;
+		chunk->next = pid_list->upper_list;
+		pid_list->upper_list = chunk;
+		pid_list->free_upper_chunks++;
+	}
+
+	for (i = 0; i < CHUNK_ALLOC; i++) {
+		union lower_chunk *chunk;
+
+		chunk = kzalloc(sizeof(*chunk), GFP_KERNEL);
+		if (!chunk)
+			break;
+		chunk->next = pid_list->lower_list;
+		pid_list->lower_list = chunk;
+		pid_list->free_lower_chunks++;
+	}
+
+	return pid_list;
+}
+
+/**
+ * trace_pid_list_free - Frees an allocated pid_list.
+ *
+ * Frees the memory for a pid_list that was allocated.
+ */
+void trace_pid_list_free(struct trace_pid_list *pid_list)
+{
+	union upper_chunk *upper;
+	union lower_chunk *lower;
+	int i, j;
+
+	if (!pid_list)
+		return;
+
+	irq_work_sync(&pid_list->refill_irqwork);
+
+	while (pid_list->lower_list) {
+		union lower_chunk *chunk;
+
+		chunk = pid_list->lower_list;
+		pid_list->lower_list = pid_list->lower_list->next;
+		kfree(chunk);
+	}
+
+	while (pid_list->upper_list) {
+		union upper_chunk *chunk;
+
+		chunk = pid_list->upper_list;
+		pid_list->upper_list = pid_list->upper_list->next;
+		kfree(chunk);
+	}
+
+	for (i = 0; i < UPPER1_SIZE; i++) {
+		upper = pid_list->upper[i];
+		if (upper) {
+			for (j = 0; j < UPPER2_SIZE; j++) {
+				lower = upper->data[j];
+				kfree(lower);
+			}
+			kfree(upper);
+		}
+	}
+	kfree(pid_list);
+}
diff --git a/kernel/trace/pid_list.h b/kernel/trace/pid_list.h
new file mode 100644
index 000000000..62e73f1ac
--- /dev/null
+++ b/kernel/trace/pid_list.h
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* Do not include this file directly. */
+
+#ifndef _TRACE_INTERNAL_PID_LIST_H
+#define _TRACE_INTERNAL_PID_LIST_H
+
+/*
+ * In order to keep track of what pids to trace, a tree is created much
+ * like page tables are used. This creates a sparse bit map, where
+ * the tree is filled in when needed. A PID is at most 30 bits (see
+ * linux/thread.h), and is broken up into 3 sections based on the bit map
+ * of the bits. The 8 MSB is the "upper1" section. The next 8 MSB is the
+ * "upper2" section and the 14 LSB is the "lower" section.
+ *
+ * A trace_pid_list structure holds the "upper1" section, in an
+ * array of 256 pointers (1 or 2K in size) to "upper_chunk" unions, where
+ * each has an array of 256 pointers (1 or 2K in size) to the "lower_chunk"
+ * structures, where each has an array of size 2K bytes representing a bitmask
+ * of the 14 LSB of the PID (256 * 8 = 2048)
+ *
+ * When a trace_pid_list is allocated, it includes the 256 pointer array
+ * of the upper1 unions. Then a "cache" of upper and lower is allocated
+ * where these will be assigned as needed.
+ *
+ * When a bit is set in the pid_list bitmask, the pid to use has
+ * the 8 MSB masked, and this is used to index the array in the
+ * pid_list to find the next upper union. If the element is NULL,
+ * then one is retrieved from the upper_list cache. If none is
+ * available, then -ENOMEM is returned.
+ *
+ * The next 8 MSB is used to index into the "upper2" section. If this
+ * element is NULL, then it is retrieved from the lower_list cache.
+ * Again, if one is not available -ENOMEM is returned.
+ *
+ * Finally the 14 LSB of the PID is used to set the bit in the 16384
+ * bitmask (made up of 2K bytes).
+ *
+ * When the second upper section or the lower section has their last
+ * bit cleared, they are added back to the free list to be reused
+ * when needed.
+ */
+
+#define UPPER_BITS	8
+#define UPPER_MAX	(1 << UPPER_BITS)
+#define UPPER1_SIZE	(1 << UPPER_BITS)
+#define UPPER2_SIZE	(1 << UPPER_BITS)
+
+#define LOWER_BITS	14
+#define LOWER_MAX	(1 << LOWER_BITS)
+#define LOWER_SIZE	(LOWER_MAX / BITS_PER_LONG)
+
+#define UPPER1_SHIFT	(LOWER_BITS + UPPER_BITS)
+#define UPPER2_SHIFT	LOWER_BITS
+#define LOWER_MASK	(LOWER_MAX - 1)
+
+#define UPPER_MASK	(UPPER_MAX - 1)
+
+/* According to linux/thread.h pids can not be bigger than or equal to 1 << 30 */
+#define MAX_PID		(1 << 30)
+
+/* Just keep 6 chunks of both upper and lower in the cache on alloc */
+#define CHUNK_ALLOC 6
+
+/* Have 2 chunks free, trigger a refill of the cache */
+#define CHUNK_REALLOC 2
+
+union lower_chunk {
+	union lower_chunk		*next;
+	unsigned long			data[LOWER_SIZE]; // 2K in size
+};
+
+union upper_chunk {
+	union upper_chunk		*next;
+	union lower_chunk		*data[UPPER2_SIZE]; // 1 or 2K in size
+};
+
+struct trace_pid_list {
+	raw_spinlock_t			lock;
+	struct irq_work			refill_irqwork;
+	union upper_chunk		*upper[UPPER1_SIZE]; // 1 or 2K in size
+	union upper_chunk		*upper_list;
+	union lower_chunk		*lower_list;
+	int				free_upper_chunks;
+	int				free_lower_chunks;
+};
+
+#endif /* _TRACE_INTERNAL_PID_LIST_H */
diff --git a/kernel/trace/power-traces.c b/kernel/trace/power-traces.c
new file mode 100644
index 000000000..21bb161c2
--- /dev/null
+++ b/kernel/trace/power-traces.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Power trace points
+ *
+ * Copyright (C) 2009 Arjan van de Ven <arjan@linux.intel.com>
+ */
+
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/power.h>
+
+EXPORT_TRACEPOINT_SYMBOL_GPL(suspend_resume);
+EXPORT_TRACEPOINT_SYMBOL_GPL(cpu_idle);
+EXPORT_TRACEPOINT_SYMBOL_GPL(cpu_frequency);
+EXPORT_TRACEPOINT_SYMBOL_GPL(powernv_throttle);
+
diff --git a/kernel/trace/preemptirq_delay_test.c b/kernel/trace/preemptirq_delay_test.c
new file mode 100644
index 000000000..8c4ffd076
--- /dev/null
+++ b/kernel/trace/preemptirq_delay_test.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Preempt / IRQ disable delay thread to test latency tracers
+ *
+ * Copyright (C) 2018 Joel Fernandes (Google) <joel@joelfernandes.org>
+ */
+
+#include <linux/trace_clock.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/kobject.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/completion.h>
+
+static ulong delay = 100;
+static char test_mode[12] = "irq";
+static uint burst_size = 1;
+static int  cpu_affinity = -1;
+
+module_param_named(delay, delay, ulong, 0444);
+module_param_string(test_mode, test_mode, 12, 0444);
+module_param_named(burst_size, burst_size, uint, 0444);
+module_param_named(cpu_affinity, cpu_affinity, int, 0444);
+MODULE_PARM_DESC(delay, "Period in microseconds (100 us default)");
+MODULE_PARM_DESC(test_mode, "Mode of the test such as preempt, irq, or alternate (default irq)");
+MODULE_PARM_DESC(burst_size, "The size of a burst (default 1)");
+MODULE_PARM_DESC(cpu_affinity, "Cpu num test is running on");
+
+static struct completion done;
+
+#define MIN(x, y) ((x) < (y) ? (x) : (y))
+
+static void busy_wait(ulong time)
+{
+	u64 start, end;
+
+	start = trace_clock_local();
+
+	do {
+		end = trace_clock_local();
+		if (kthread_should_stop())
+			break;
+	} while ((end - start) < (time * 1000));
+}
+
+static __always_inline void irqoff_test(void)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	busy_wait(delay);
+	local_irq_restore(flags);
+}
+
+static __always_inline void preemptoff_test(void)
+{
+	preempt_disable();
+	busy_wait(delay);
+	preempt_enable();
+}
+
+static void execute_preemptirqtest(int idx)
+{
+	if (!strcmp(test_mode, "irq"))
+		irqoff_test();
+	else if (!strcmp(test_mode, "preempt"))
+		preemptoff_test();
+	else if (!strcmp(test_mode, "alternate")) {
+		if (idx % 2 == 0)
+			irqoff_test();
+		else
+			preemptoff_test();
+	}
+}
+
+#define DECLARE_TESTFN(POSTFIX)				\
+	static void preemptirqtest_##POSTFIX(int idx)	\
+	{						\
+		execute_preemptirqtest(idx);		\
+	}						\
+
+/*
+ * We create 10 different functions, so that we can get 10 different
+ * backtraces.
+ */
+DECLARE_TESTFN(0)
+DECLARE_TESTFN(1)
+DECLARE_TESTFN(2)
+DECLARE_TESTFN(3)
+DECLARE_TESTFN(4)
+DECLARE_TESTFN(5)
+DECLARE_TESTFN(6)
+DECLARE_TESTFN(7)
+DECLARE_TESTFN(8)
+DECLARE_TESTFN(9)
+
+static void (*testfuncs[])(int)  = {
+	preemptirqtest_0,
+	preemptirqtest_1,
+	preemptirqtest_2,
+	preemptirqtest_3,
+	preemptirqtest_4,
+	preemptirqtest_5,
+	preemptirqtest_6,
+	preemptirqtest_7,
+	preemptirqtest_8,
+	preemptirqtest_9,
+};
+
+#define NR_TEST_FUNCS ARRAY_SIZE(testfuncs)
+
+static int preemptirq_delay_run(void *data)
+{
+	int i;
+	int s = MIN(burst_size, NR_TEST_FUNCS);
+	struct cpumask cpu_mask;
+
+	if (cpu_affinity > -1) {
+		cpumask_clear(&cpu_mask);
+		cpumask_set_cpu(cpu_affinity, &cpu_mask);
+		if (set_cpus_allowed_ptr(current, &cpu_mask))
+			pr_err("cpu_affinity:%d, failed\n", cpu_affinity);
+	}
+
+	for (i = 0; i < s; i++)
+		(testfuncs[i])(i);
+
+	complete(&done);
+
+	set_current_state(TASK_INTERRUPTIBLE);
+	while (!kthread_should_stop()) {
+		schedule();
+		set_current_state(TASK_INTERRUPTIBLE);
+	}
+
+	__set_current_state(TASK_RUNNING);
+
+	return 0;
+}
+
+static int preemptirq_run_test(void)
+{
+	struct task_struct *task;
+	char task_name[50];
+
+	init_completion(&done);
+
+	snprintf(task_name, sizeof(task_name), "%s_test", test_mode);
+	task =  kthread_run(preemptirq_delay_run, NULL, task_name);
+	if (IS_ERR(task))
+		return PTR_ERR(task);
+	if (task) {
+		wait_for_completion(&done);
+		kthread_stop(task);
+	}
+	return 0;
+}
+
+
+static ssize_t trigger_store(struct kobject *kobj, struct kobj_attribute *attr,
+			 const char *buf, size_t count)
+{
+	ssize_t ret;
+
+	ret = preemptirq_run_test();
+	if (ret)
+		return ret;
+	return count;
+}
+
+static struct kobj_attribute trigger_attribute =
+	__ATTR(trigger, 0200, NULL, trigger_store);
+
+static struct attribute *attrs[] = {
+	&trigger_attribute.attr,
+	NULL,
+};
+
+static struct attribute_group attr_group = {
+	.attrs = attrs,
+};
+
+static struct kobject *preemptirq_delay_kobj;
+
+static int __init preemptirq_delay_init(void)
+{
+	int retval;
+
+	retval = preemptirq_run_test();
+	if (retval != 0)
+		return retval;
+
+	preemptirq_delay_kobj = kobject_create_and_add("preemptirq_delay_test",
+						       kernel_kobj);
+	if (!preemptirq_delay_kobj)
+		return -ENOMEM;
+
+	retval = sysfs_create_group(preemptirq_delay_kobj, &attr_group);
+	if (retval)
+		kobject_put(preemptirq_delay_kobj);
+
+	return retval;
+}
+
+static void __exit preemptirq_delay_exit(void)
+{
+	kobject_put(preemptirq_delay_kobj);
+}
+
+module_init(preemptirq_delay_init)
+module_exit(preemptirq_delay_exit)
+MODULE_LICENSE("GPL v2");
diff --git a/kernel/trace/rethook.c b/kernel/trace/rethook.c
new file mode 100644
index 000000000..3686626b5
--- /dev/null
+++ b/kernel/trace/rethook.c
@@ -0,0 +1,346 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define pr_fmt(fmt) "rethook: " fmt
+
+#include <linux/bug.h>
+#include <linux/kallsyms.h>
+#include <linux/kprobes.h>
+#include <linux/preempt.h>
+#include <linux/rethook.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+
+/* Return hook list (shadow stack by list) */
+
+/*
+ * This function is called from delayed_put_task_struct() when a task is
+ * dead and cleaned up to recycle any kretprobe instances associated with
+ * this task. These left over instances represent probed functions that
+ * have been called but will never return.
+ */
+void rethook_flush_task(struct task_struct *tk)
+{
+	struct rethook_node *rhn;
+	struct llist_node *node;
+
+	node = __llist_del_all(&tk->rethooks);
+	while (node) {
+		rhn = container_of(node, struct rethook_node, llist);
+		node = node->next;
+		preempt_disable();
+		rethook_recycle(rhn);
+		preempt_enable();
+	}
+}
+
+static void rethook_free_rcu(struct rcu_head *head)
+{
+	struct rethook *rh = container_of(head, struct rethook, rcu);
+	struct rethook_node *rhn;
+	struct freelist_node *node;
+	int count = 1;
+
+	node = rh->pool.head;
+	while (node) {
+		rhn = container_of(node, struct rethook_node, freelist);
+		node = node->next;
+		kfree(rhn);
+		count++;
+	}
+
+	/* The rh->ref is the number of pooled node + 1 */
+	if (refcount_sub_and_test(count, &rh->ref))
+		kfree(rh);
+}
+
+/**
+ * rethook_stop() - Stop using a rethook.
+ * @rh: the struct rethook to stop.
+ *
+ * Stop using a rethook to prepare for freeing it. If you want to wait for
+ * all running rethook handler before calling rethook_free(), you need to
+ * call this first and wait RCU, and call rethook_free().
+ */
+void rethook_stop(struct rethook *rh)
+{
+	rcu_assign_pointer(rh->handler, NULL);
+}
+
+/**
+ * rethook_free() - Free struct rethook.
+ * @rh: the struct rethook to be freed.
+ *
+ * Free the rethook. Before calling this function, user must ensure the
+ * @rh::data is cleaned if needed (or, the handler can access it after
+ * calling this function.) This function will set the @rh to be freed
+ * after all rethook_node are freed (not soon). And the caller must
+ * not touch @rh after calling this.
+ */
+void rethook_free(struct rethook *rh)
+{
+	rethook_stop(rh);
+
+	call_rcu(&rh->rcu, rethook_free_rcu);
+}
+
+static inline rethook_handler_t rethook_get_handler(struct rethook *rh)
+{
+	return (rethook_handler_t)rcu_dereference_check(rh->handler,
+							rcu_read_lock_any_held());
+}
+
+/**
+ * rethook_alloc() - Allocate struct rethook.
+ * @data: a data to pass the @handler when hooking the return.
+ * @handler: the return hook callback function.
+ *
+ * Allocate and initialize a new rethook with @data and @handler.
+ * Return NULL if memory allocation fails or @handler is NULL.
+ * Note that @handler == NULL means this rethook is going to be freed.
+ */
+struct rethook *rethook_alloc(void *data, rethook_handler_t handler)
+{
+	struct rethook *rh = kzalloc(sizeof(struct rethook), GFP_KERNEL);
+
+	if (!rh || !handler) {
+		kfree(rh);
+		return NULL;
+	}
+
+	rh->data = data;
+	rcu_assign_pointer(rh->handler, handler);
+	rh->pool.head = NULL;
+	refcount_set(&rh->ref, 1);
+
+	return rh;
+}
+
+/**
+ * rethook_add_node() - Add a new node to the rethook.
+ * @rh: the struct rethook.
+ * @node: the struct rethook_node to be added.
+ *
+ * Add @node to @rh. User must allocate @node (as a part of user's
+ * data structure.) The @node fields are initialized in this function.
+ */
+void rethook_add_node(struct rethook *rh, struct rethook_node *node)
+{
+	node->rethook = rh;
+	freelist_add(&node->freelist, &rh->pool);
+	refcount_inc(&rh->ref);
+}
+
+static void free_rethook_node_rcu(struct rcu_head *head)
+{
+	struct rethook_node *node = container_of(head, struct rethook_node, rcu);
+
+	if (refcount_dec_and_test(&node->rethook->ref))
+		kfree(node->rethook);
+	kfree(node);
+}
+
+/**
+ * rethook_recycle() - return the node to rethook.
+ * @node: The struct rethook_node to be returned.
+ *
+ * Return back the @node to @node::rethook. If the @node::rethook is already
+ * marked as freed, this will free the @node.
+ */
+void rethook_recycle(struct rethook_node *node)
+{
+	rethook_handler_t handler;
+
+	handler = rethook_get_handler(node->rethook);
+	if (likely(handler))
+		freelist_add(&node->freelist, &node->rethook->pool);
+	else
+		call_rcu(&node->rcu, free_rethook_node_rcu);
+}
+NOKPROBE_SYMBOL(rethook_recycle);
+
+/**
+ * rethook_try_get() - get an unused rethook node.
+ * @rh: The struct rethook which pools the nodes.
+ *
+ * Get an unused rethook node from @rh. If the node pool is empty, this
+ * will return NULL. Caller must disable preemption.
+ */
+struct rethook_node *rethook_try_get(struct rethook *rh)
+{
+	rethook_handler_t handler = rethook_get_handler(rh);
+	struct freelist_node *fn;
+
+	/* Check whether @rh is going to be freed. */
+	if (unlikely(!handler))
+		return NULL;
+
+	/*
+	 * This expects the caller will set up a rethook on a function entry.
+	 * When the function returns, the rethook will eventually be reclaimed
+	 * or released in the rethook_recycle() with call_rcu().
+	 * This means the caller must be run in the RCU-availabe context.
+	 */
+	if (unlikely(!rcu_is_watching()))
+		return NULL;
+
+	fn = freelist_try_get(&rh->pool);
+	if (!fn)
+		return NULL;
+
+	return container_of(fn, struct rethook_node, freelist);
+}
+NOKPROBE_SYMBOL(rethook_try_get);
+
+/**
+ * rethook_hook() - Hook the current function return.
+ * @node: The struct rethook node to hook the function return.
+ * @regs: The struct pt_regs for the function entry.
+ * @mcount: True if this is called from mcount(ftrace) context.
+ *
+ * Hook the current running function return. This must be called when the
+ * function entry (or at least @regs must be the registers of the function
+ * entry.) @mcount is used for identifying the context. If this is called
+ * from ftrace (mcount) callback, @mcount must be set true. If this is called
+ * from the real function entry (e.g. kprobes) @mcount must be set false.
+ * This is because the way to hook the function return depends on the context.
+ */
+void rethook_hook(struct rethook_node *node, struct pt_regs *regs, bool mcount)
+{
+	arch_rethook_prepare(node, regs, mcount);
+	__llist_add(&node->llist, &current->rethooks);
+}
+NOKPROBE_SYMBOL(rethook_hook);
+
+/* This assumes the 'tsk' is the current task or is not running. */
+static unsigned long __rethook_find_ret_addr(struct task_struct *tsk,
+					     struct llist_node **cur)
+{
+	struct rethook_node *rh = NULL;
+	struct llist_node *node = *cur;
+
+	if (!node)
+		node = tsk->rethooks.first;
+	else
+		node = node->next;
+
+	while (node) {
+		rh = container_of(node, struct rethook_node, llist);
+		if (rh->ret_addr != (unsigned long)arch_rethook_trampoline) {
+			*cur = node;
+			return rh->ret_addr;
+		}
+		node = node->next;
+	}
+	return 0;
+}
+NOKPROBE_SYMBOL(__rethook_find_ret_addr);
+
+/**
+ * rethook_find_ret_addr -- Find correct return address modified by rethook
+ * @tsk: Target task
+ * @frame: A frame pointer
+ * @cur: a storage of the loop cursor llist_node pointer for next call
+ *
+ * Find the correct return address modified by a rethook on @tsk in unsigned
+ * long type.
+ * The @tsk must be 'current' or a task which is not running. @frame is a hint
+ * to get the currect return address - which is compared with the
+ * rethook::frame field. The @cur is a loop cursor for searching the
+ * kretprobe return addresses on the @tsk. The '*@cur' should be NULL at the
+ * first call, but '@cur' itself must NOT NULL.
+ *
+ * Returns found address value or zero if not found.
+ */
+unsigned long rethook_find_ret_addr(struct task_struct *tsk, unsigned long frame,
+				    struct llist_node **cur)
+{
+	struct rethook_node *rhn = NULL;
+	unsigned long ret;
+
+	if (WARN_ON_ONCE(!cur))
+		return 0;
+
+	if (WARN_ON_ONCE(tsk != current && task_is_running(tsk)))
+		return 0;
+
+	do {
+		ret = __rethook_find_ret_addr(tsk, cur);
+		if (!ret)
+			break;
+		rhn = container_of(*cur, struct rethook_node, llist);
+	} while (rhn->frame != frame);
+
+	return ret;
+}
+NOKPROBE_SYMBOL(rethook_find_ret_addr);
+
+void __weak arch_rethook_fixup_return(struct pt_regs *regs,
+				      unsigned long correct_ret_addr)
+{
+	/*
+	 * Do nothing by default. If the architecture which uses a
+	 * frame pointer to record real return address on the stack,
+	 * it should fill this function to fixup the return address
+	 * so that stacktrace works from the rethook handler.
+	 */
+}
+
+/* This function will be called from each arch-defined trampoline. */
+unsigned long rethook_trampoline_handler(struct pt_regs *regs,
+					 unsigned long frame)
+{
+	struct llist_node *first, *node = NULL;
+	unsigned long correct_ret_addr;
+	rethook_handler_t handler;
+	struct rethook_node *rhn;
+
+	correct_ret_addr = __rethook_find_ret_addr(current, &node);
+	if (!correct_ret_addr) {
+		pr_err("rethook: Return address not found! Maybe there is a bug in the kernel\n");
+		BUG_ON(1);
+	}
+
+	instruction_pointer_set(regs, correct_ret_addr);
+
+	/*
+	 * These loops must be protected from rethook_free_rcu() because those
+	 * are accessing 'rhn->rethook'.
+	 */
+	preempt_disable_notrace();
+
+	/*
+	 * Run the handler on the shadow stack. Do not unlink the list here because
+	 * stackdump inside the handlers needs to decode it.
+	 */
+	first = current->rethooks.first;
+	while (first) {
+		rhn = container_of(first, struct rethook_node, llist);
+		if (WARN_ON_ONCE(rhn->frame != frame))
+			break;
+		handler = rethook_get_handler(rhn->rethook);
+		if (handler)
+			handler(rhn, rhn->rethook->data, regs);
+
+		if (first == node)
+			break;
+		first = first->next;
+	}
+
+	/* Fixup registers for returning to correct address. */
+	arch_rethook_fixup_return(regs, correct_ret_addr);
+
+	/* Unlink used shadow stack */
+	first = current->rethooks.first;
+	current->rethooks.first = node->next;
+	node->next = NULL;
+
+	while (first) {
+		rhn = container_of(first, struct rethook_node, llist);
+		first = first->next;
+		rethook_recycle(rhn);
+	}
+	preempt_enable_notrace();
+
+	return correct_ret_addr;
+}
+NOKPROBE_SYMBOL(rethook_trampoline_handler);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
new file mode 100644
index 000000000..1285e7fb5
--- /dev/null
+++ b/kernel/trace/ring_buffer.c
@@ -0,0 +1,6178 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic ring buffer
+ *
+ * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
+ */
+#include <linux/trace_recursion.h>
+#include <linux/trace_events.h>
+#include <linux/ring_buffer.h>
+#include <linux/trace_clock.h>
+#include <linux/sched/clock.h>
+#include <linux/trace_seq.h>
+#include <linux/spinlock.h>
+#include <linux/irq_work.h>
+#include <linux/security.h>
+#include <linux/uaccess.h>
+#include <linux/hardirq.h>
+#include <linux/kthread.h>	/* for self test */
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/hash.h>
+#include <linux/list.h>
+#include <linux/cpu.h>
+#include <linux/oom.h>
+
+#include <asm/local.h>
+
+/*
+ * The "absolute" timestamp in the buffer is only 59 bits.
+ * If a clock has the 5 MSBs set, it needs to be saved and
+ * reinserted.
+ */
+#define TS_MSB		(0xf8ULL << 56)
+#define ABS_TS_MASK	(~TS_MSB)
+
+static void update_pages_handler(struct work_struct *work);
+
+/*
+ * The ring buffer header is special. We must manually up keep it.
+ */
+int ring_buffer_print_entry_header(struct trace_seq *s)
+{
+	trace_seq_puts(s, "# compressed entry header\n");
+	trace_seq_puts(s, "\ttype_len    :    5 bits\n");
+	trace_seq_puts(s, "\ttime_delta  :   27 bits\n");
+	trace_seq_puts(s, "\tarray       :   32 bits\n");
+	trace_seq_putc(s, '\n');
+	trace_seq_printf(s, "\tpadding     : type == %d\n",
+			 RINGBUF_TYPE_PADDING);
+	trace_seq_printf(s, "\ttime_extend : type == %d\n",
+			 RINGBUF_TYPE_TIME_EXTEND);
+	trace_seq_printf(s, "\ttime_stamp : type == %d\n",
+			 RINGBUF_TYPE_TIME_STAMP);
+	trace_seq_printf(s, "\tdata max type_len  == %d\n",
+			 RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
+
+	return !trace_seq_has_overflowed(s);
+}
+
+/*
+ * The ring buffer is made up of a list of pages. A separate list of pages is
+ * allocated for each CPU. A writer may only write to a buffer that is
+ * associated with the CPU it is currently executing on.  A reader may read
+ * from any per cpu buffer.
+ *
+ * The reader is special. For each per cpu buffer, the reader has its own
+ * reader page. When a reader has read the entire reader page, this reader
+ * page is swapped with another page in the ring buffer.
+ *
+ * Now, as long as the writer is off the reader page, the reader can do what
+ * ever it wants with that page. The writer will never write to that page
+ * again (as long as it is out of the ring buffer).
+ *
+ * Here's some silly ASCII art.
+ *
+ *   +------+
+ *   |reader|          RING BUFFER
+ *   |page  |
+ *   +------+        +---+   +---+   +---+
+ *                   |   |-->|   |-->|   |
+ *                   +---+   +---+   +---+
+ *                     ^               |
+ *                     |               |
+ *                     +---------------+
+ *
+ *
+ *   +------+
+ *   |reader|          RING BUFFER
+ *   |page  |------------------v
+ *   +------+        +---+   +---+   +---+
+ *                   |   |-->|   |-->|   |
+ *                   +---+   +---+   +---+
+ *                     ^               |
+ *                     |               |
+ *                     +---------------+
+ *
+ *
+ *   +------+
+ *   |reader|          RING BUFFER
+ *   |page  |------------------v
+ *   +------+        +---+   +---+   +---+
+ *      ^            |   |-->|   |-->|   |
+ *      |            +---+   +---+   +---+
+ *      |                              |
+ *      |                              |
+ *      +------------------------------+
+ *
+ *
+ *   +------+
+ *   |buffer|          RING BUFFER
+ *   |page  |------------------v
+ *   +------+        +---+   +---+   +---+
+ *      ^            |   |   |   |-->|   |
+ *      |   New      +---+   +---+   +---+
+ *      |  Reader------^               |
+ *      |   page                       |
+ *      +------------------------------+
+ *
+ *
+ * After we make this swap, the reader can hand this page off to the splice
+ * code and be done with it. It can even allocate a new page if it needs to
+ * and swap that into the ring buffer.
+ *
+ * We will be using cmpxchg soon to make all this lockless.
+ *
+ */
+
+/* Used for individual buffers (after the counter) */
+#define RB_BUFFER_OFF		(1 << 20)
+
+#define BUF_PAGE_HDR_SIZE offsetof(struct buffer_data_page, data)
+
+#define RB_EVNT_HDR_SIZE (offsetof(struct ring_buffer_event, array))
+#define RB_ALIGNMENT		4U
+#define RB_MAX_SMALL_DATA	(RB_ALIGNMENT * RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
+#define RB_EVNT_MIN_SIZE	8U	/* two 32bit words */
+
+#ifndef CONFIG_HAVE_64BIT_ALIGNED_ACCESS
+# define RB_FORCE_8BYTE_ALIGNMENT	0
+# define RB_ARCH_ALIGNMENT		RB_ALIGNMENT
+#else
+# define RB_FORCE_8BYTE_ALIGNMENT	1
+# define RB_ARCH_ALIGNMENT		8U
+#endif
+
+#define RB_ALIGN_DATA		__aligned(RB_ARCH_ALIGNMENT)
+
+/* define RINGBUF_TYPE_DATA for 'case RINGBUF_TYPE_DATA:' */
+#define RINGBUF_TYPE_DATA 0 ... RINGBUF_TYPE_DATA_TYPE_LEN_MAX
+
+enum {
+	RB_LEN_TIME_EXTEND = 8,
+	RB_LEN_TIME_STAMP =  8,
+};
+
+#define skip_time_extend(event) \
+	((struct ring_buffer_event *)((char *)event + RB_LEN_TIME_EXTEND))
+
+#define extended_time(event) \
+	(event->type_len >= RINGBUF_TYPE_TIME_EXTEND)
+
+static inline int rb_null_event(struct ring_buffer_event *event)
+{
+	return event->type_len == RINGBUF_TYPE_PADDING && !event->time_delta;
+}
+
+static void rb_event_set_padding(struct ring_buffer_event *event)
+{
+	/* padding has a NULL time_delta */
+	event->type_len = RINGBUF_TYPE_PADDING;
+	event->time_delta = 0;
+}
+
+static unsigned
+rb_event_data_length(struct ring_buffer_event *event)
+{
+	unsigned length;
+
+	if (event->type_len)
+		length = event->type_len * RB_ALIGNMENT;
+	else
+		length = event->array[0];
+	return length + RB_EVNT_HDR_SIZE;
+}
+
+/*
+ * Return the length of the given event. Will return
+ * the length of the time extend if the event is a
+ * time extend.
+ */
+static inline unsigned
+rb_event_length(struct ring_buffer_event *event)
+{
+	switch (event->type_len) {
+	case RINGBUF_TYPE_PADDING:
+		if (rb_null_event(event))
+			/* undefined */
+			return -1;
+		return  event->array[0] + RB_EVNT_HDR_SIZE;
+
+	case RINGBUF_TYPE_TIME_EXTEND:
+		return RB_LEN_TIME_EXTEND;
+
+	case RINGBUF_TYPE_TIME_STAMP:
+		return RB_LEN_TIME_STAMP;
+
+	case RINGBUF_TYPE_DATA:
+		return rb_event_data_length(event);
+	default:
+		WARN_ON_ONCE(1);
+	}
+	/* not hit */
+	return 0;
+}
+
+/*
+ * Return total length of time extend and data,
+ *   or just the event length for all other events.
+ */
+static inline unsigned
+rb_event_ts_length(struct ring_buffer_event *event)
+{
+	unsigned len = 0;
+
+	if (extended_time(event)) {
+		/* time extends include the data event after it */
+		len = RB_LEN_TIME_EXTEND;
+		event = skip_time_extend(event);
+	}
+	return len + rb_event_length(event);
+}
+
+/**
+ * ring_buffer_event_length - return the length of the event
+ * @event: the event to get the length of
+ *
+ * Returns the size of the data load of a data event.
+ * If the event is something other than a data event, it
+ * returns the size of the event itself. With the exception
+ * of a TIME EXTEND, where it still returns the size of the
+ * data load of the data event after it.
+ */
+unsigned ring_buffer_event_length(struct ring_buffer_event *event)
+{
+	unsigned length;
+
+	if (extended_time(event))
+		event = skip_time_extend(event);
+
+	length = rb_event_length(event);
+	if (event->type_len > RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
+		return length;
+	length -= RB_EVNT_HDR_SIZE;
+	if (length > RB_MAX_SMALL_DATA + sizeof(event->array[0]))
+                length -= sizeof(event->array[0]);
+	return length;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_event_length);
+
+/* inline for ring buffer fast paths */
+static __always_inline void *
+rb_event_data(struct ring_buffer_event *event)
+{
+	if (extended_time(event))
+		event = skip_time_extend(event);
+	WARN_ON_ONCE(event->type_len > RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
+	/* If length is in len field, then array[0] has the data */
+	if (event->type_len)
+		return (void *)&event->array[0];
+	/* Otherwise length is in array[0] and array[1] has the data */
+	return (void *)&event->array[1];
+}
+
+/**
+ * ring_buffer_event_data - return the data of the event
+ * @event: the event to get the data from
+ */
+void *ring_buffer_event_data(struct ring_buffer_event *event)
+{
+	return rb_event_data(event);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_event_data);
+
+#define for_each_buffer_cpu(buffer, cpu)		\
+	for_each_cpu(cpu, buffer->cpumask)
+
+#define for_each_online_buffer_cpu(buffer, cpu)		\
+	for_each_cpu_and(cpu, buffer->cpumask, cpu_online_mask)
+
+#define TS_SHIFT	27
+#define TS_MASK		((1ULL << TS_SHIFT) - 1)
+#define TS_DELTA_TEST	(~TS_MASK)
+
+static u64 rb_event_time_stamp(struct ring_buffer_event *event)
+{
+	u64 ts;
+
+	ts = event->array[0];
+	ts <<= TS_SHIFT;
+	ts += event->time_delta;
+
+	return ts;
+}
+
+/* Flag when events were overwritten */
+#define RB_MISSED_EVENTS	(1 << 31)
+/* Missed count stored at end */
+#define RB_MISSED_STORED	(1 << 30)
+
+struct buffer_data_page {
+	u64		 time_stamp;	/* page time stamp */
+	local_t		 commit;	/* write committed index */
+	unsigned char	 data[] RB_ALIGN_DATA;	/* data of buffer page */
+};
+
+/*
+ * Note, the buffer_page list must be first. The buffer pages
+ * are allocated in cache lines, which means that each buffer
+ * page will be at the beginning of a cache line, and thus
+ * the least significant bits will be zero. We use this to
+ * add flags in the list struct pointers, to make the ring buffer
+ * lockless.
+ */
+struct buffer_page {
+	struct list_head list;		/* list of buffer pages */
+	local_t		 write;		/* index for next write */
+	unsigned	 read;		/* index for next read */
+	local_t		 entries;	/* entries on this page */
+	unsigned long	 real_end;	/* real end of data */
+	struct buffer_data_page *page;	/* Actual data page */
+};
+
+/*
+ * The buffer page counters, write and entries, must be reset
+ * atomically when crossing page boundaries. To synchronize this
+ * update, two counters are inserted into the number. One is
+ * the actual counter for the write position or count on the page.
+ *
+ * The other is a counter of updaters. Before an update happens
+ * the update partition of the counter is incremented. This will
+ * allow the updater to update the counter atomically.
+ *
+ * The counter is 20 bits, and the state data is 12.
+ */
+#define RB_WRITE_MASK		0xfffff
+#define RB_WRITE_INTCNT		(1 << 20)
+
+static void rb_init_page(struct buffer_data_page *bpage)
+{
+	local_set(&bpage->commit, 0);
+}
+
+static __always_inline unsigned int rb_page_commit(struct buffer_page *bpage)
+{
+	return local_read(&bpage->page->commit);
+}
+
+static void free_buffer_page(struct buffer_page *bpage)
+{
+	free_page((unsigned long)bpage->page);
+	kfree(bpage);
+}
+
+/*
+ * We need to fit the time_stamp delta into 27 bits.
+ */
+static inline int test_time_stamp(u64 delta)
+{
+	if (delta & TS_DELTA_TEST)
+		return 1;
+	return 0;
+}
+
+#define BUF_PAGE_SIZE (PAGE_SIZE - BUF_PAGE_HDR_SIZE)
+
+/* Max payload is BUF_PAGE_SIZE - header (8bytes) */
+#define BUF_MAX_DATA_SIZE (BUF_PAGE_SIZE - (sizeof(u32) * 2))
+
+int ring_buffer_print_page_header(struct trace_seq *s)
+{
+	struct buffer_data_page field;
+
+	trace_seq_printf(s, "\tfield: u64 timestamp;\t"
+			 "offset:0;\tsize:%u;\tsigned:%u;\n",
+			 (unsigned int)sizeof(field.time_stamp),
+			 (unsigned int)is_signed_type(u64));
+
+	trace_seq_printf(s, "\tfield: local_t commit;\t"
+			 "offset:%u;\tsize:%u;\tsigned:%u;\n",
+			 (unsigned int)offsetof(typeof(field), commit),
+			 (unsigned int)sizeof(field.commit),
+			 (unsigned int)is_signed_type(long));
+
+	trace_seq_printf(s, "\tfield: int overwrite;\t"
+			 "offset:%u;\tsize:%u;\tsigned:%u;\n",
+			 (unsigned int)offsetof(typeof(field), commit),
+			 1,
+			 (unsigned int)is_signed_type(long));
+
+	trace_seq_printf(s, "\tfield: char data;\t"
+			 "offset:%u;\tsize:%u;\tsigned:%u;\n",
+			 (unsigned int)offsetof(typeof(field), data),
+			 (unsigned int)BUF_PAGE_SIZE,
+			 (unsigned int)is_signed_type(char));
+
+	return !trace_seq_has_overflowed(s);
+}
+
+struct rb_irq_work {
+	struct irq_work			work;
+	wait_queue_head_t		waiters;
+	wait_queue_head_t		full_waiters;
+	long				wait_index;
+	bool				waiters_pending;
+	bool				full_waiters_pending;
+	bool				wakeup_full;
+};
+
+/*
+ * Structure to hold event state and handle nested events.
+ */
+struct rb_event_info {
+	u64			ts;
+	u64			delta;
+	u64			before;
+	u64			after;
+	unsigned long		length;
+	struct buffer_page	*tail_page;
+	int			add_timestamp;
+};
+
+/*
+ * Used for the add_timestamp
+ *  NONE
+ *  EXTEND - wants a time extend
+ *  ABSOLUTE - the buffer requests all events to have absolute time stamps
+ *  FORCE - force a full time stamp.
+ */
+enum {
+	RB_ADD_STAMP_NONE		= 0,
+	RB_ADD_STAMP_EXTEND		= BIT(1),
+	RB_ADD_STAMP_ABSOLUTE		= BIT(2),
+	RB_ADD_STAMP_FORCE		= BIT(3)
+};
+/*
+ * Used for which event context the event is in.
+ *  TRANSITION = 0
+ *  NMI     = 1
+ *  IRQ     = 2
+ *  SOFTIRQ = 3
+ *  NORMAL  = 4
+ *
+ * See trace_recursive_lock() comment below for more details.
+ */
+enum {
+	RB_CTX_TRANSITION,
+	RB_CTX_NMI,
+	RB_CTX_IRQ,
+	RB_CTX_SOFTIRQ,
+	RB_CTX_NORMAL,
+	RB_CTX_MAX
+};
+
+#if BITS_PER_LONG == 32
+#define RB_TIME_32
+#endif
+
+/* To test on 64 bit machines */
+//#define RB_TIME_32
+
+#ifdef RB_TIME_32
+
+struct rb_time_struct {
+	local_t		cnt;
+	local_t		top;
+	local_t		bottom;
+	local_t		msb;
+};
+#else
+#include <asm/local64.h>
+struct rb_time_struct {
+	local64_t	time;
+};
+#endif
+typedef struct rb_time_struct rb_time_t;
+
+#define MAX_NEST	5
+
+/*
+ * head_page == tail_page && head == tail then buffer is empty.
+ */
+struct ring_buffer_per_cpu {
+	int				cpu;
+	atomic_t			record_disabled;
+	atomic_t			resize_disabled;
+	struct trace_buffer	*buffer;
+	raw_spinlock_t			reader_lock;	/* serialize readers */
+	arch_spinlock_t			lock;
+	struct lock_class_key		lock_key;
+	struct buffer_data_page		*free_page;
+	unsigned long			nr_pages;
+	unsigned int			current_context;
+	struct list_head		*pages;
+	struct buffer_page		*head_page;	/* read from head */
+	struct buffer_page		*tail_page;	/* write to tail */
+	struct buffer_page		*commit_page;	/* committed pages */
+	struct buffer_page		*reader_page;
+	unsigned long			lost_events;
+	unsigned long			last_overrun;
+	unsigned long			nest;
+	local_t				entries_bytes;
+	local_t				entries;
+	local_t				overrun;
+	local_t				commit_overrun;
+	local_t				dropped_events;
+	local_t				committing;
+	local_t				commits;
+	local_t				pages_touched;
+	local_t				pages_lost;
+	local_t				pages_read;
+	long				last_pages_touch;
+	size_t				shortest_full;
+	unsigned long			read;
+	unsigned long			read_bytes;
+	rb_time_t			write_stamp;
+	rb_time_t			before_stamp;
+	u64				event_stamp[MAX_NEST];
+	u64				read_stamp;
+	/* pages removed since last reset */
+	unsigned long			pages_removed;
+	/* ring buffer pages to update, > 0 to add, < 0 to remove */
+	long				nr_pages_to_update;
+	struct list_head		new_pages; /* new pages to add */
+	struct work_struct		update_pages_work;
+	struct completion		update_done;
+
+	struct rb_irq_work		irq_work;
+};
+
+struct trace_buffer {
+	unsigned			flags;
+	int				cpus;
+	atomic_t			record_disabled;
+	atomic_t			resizing;
+	cpumask_var_t			cpumask;
+
+	struct lock_class_key		*reader_lock_key;
+
+	struct mutex			mutex;
+
+	struct ring_buffer_per_cpu	**buffers;
+
+	struct hlist_node		node;
+	u64				(*clock)(void);
+
+	struct rb_irq_work		irq_work;
+	bool				time_stamp_abs;
+};
+
+struct ring_buffer_iter {
+	struct ring_buffer_per_cpu	*cpu_buffer;
+	unsigned long			head;
+	unsigned long			next_event;
+	struct buffer_page		*head_page;
+	struct buffer_page		*cache_reader_page;
+	unsigned long			cache_read;
+	unsigned long			cache_pages_removed;
+	u64				read_stamp;
+	u64				page_stamp;
+	struct ring_buffer_event	*event;
+	int				missed_events;
+};
+
+#ifdef RB_TIME_32
+
+/*
+ * On 32 bit machines, local64_t is very expensive. As the ring
+ * buffer doesn't need all the features of a true 64 bit atomic,
+ * on 32 bit, it uses these functions (64 still uses local64_t).
+ *
+ * For the ring buffer, 64 bit required operations for the time is
+ * the following:
+ *
+ *  - Reads may fail if it interrupted a modification of the time stamp.
+ *      It will succeed if it did not interrupt another write even if
+ *      the read itself is interrupted by a write.
+ *      It returns whether it was successful or not.
+ *
+ *  - Writes always succeed and will overwrite other writes and writes
+ *      that were done by events interrupting the current write.
+ *
+ *  - A write followed by a read of the same time stamp will always succeed,
+ *      but may not contain the same value.
+ *
+ *  - A cmpxchg will fail if it interrupted another write or cmpxchg.
+ *      Other than that, it acts like a normal cmpxchg.
+ *
+ * The 60 bit time stamp is broken up by 30 bits in a top and bottom half
+ *  (bottom being the least significant 30 bits of the 60 bit time stamp).
+ *
+ * The two most significant bits of each half holds a 2 bit counter (0-3).
+ * Each update will increment this counter by one.
+ * When reading the top and bottom, if the two counter bits match then the
+ *  top and bottom together make a valid 60 bit number.
+ */
+#define RB_TIME_SHIFT	30
+#define RB_TIME_VAL_MASK ((1 << RB_TIME_SHIFT) - 1)
+#define RB_TIME_MSB_SHIFT	 60
+
+static inline int rb_time_cnt(unsigned long val)
+{
+	return (val >> RB_TIME_SHIFT) & 3;
+}
+
+static inline u64 rb_time_val(unsigned long top, unsigned long bottom)
+{
+	u64 val;
+
+	val = top & RB_TIME_VAL_MASK;
+	val <<= RB_TIME_SHIFT;
+	val |= bottom & RB_TIME_VAL_MASK;
+
+	return val;
+}
+
+static inline bool __rb_time_read(rb_time_t *t, u64 *ret, unsigned long *cnt)
+{
+	unsigned long top, bottom, msb;
+	unsigned long c;
+
+	/*
+	 * If the read is interrupted by a write, then the cnt will
+	 * be different. Loop until both top and bottom have been read
+	 * without interruption.
+	 */
+	do {
+		c = local_read(&t->cnt);
+		top = local_read(&t->top);
+		bottom = local_read(&t->bottom);
+		msb = local_read(&t->msb);
+	} while (c != local_read(&t->cnt));
+
+	*cnt = rb_time_cnt(top);
+
+	/* If top, msb or bottom counts don't match, this interrupted a write */
+	if (*cnt != rb_time_cnt(msb) || *cnt != rb_time_cnt(bottom))
+		return false;
+
+	/* The shift to msb will lose its cnt bits */
+	*ret = rb_time_val(top, bottom) | ((u64)msb << RB_TIME_MSB_SHIFT);
+	return true;
+}
+
+static bool rb_time_read(rb_time_t *t, u64 *ret)
+{
+	unsigned long cnt;
+
+	return __rb_time_read(t, ret, &cnt);
+}
+
+static inline unsigned long rb_time_val_cnt(unsigned long val, unsigned long cnt)
+{
+	return (val & RB_TIME_VAL_MASK) | ((cnt & 3) << RB_TIME_SHIFT);
+}
+
+static inline void rb_time_split(u64 val, unsigned long *top, unsigned long *bottom,
+				 unsigned long *msb)
+{
+	*top = (unsigned long)((val >> RB_TIME_SHIFT) & RB_TIME_VAL_MASK);
+	*bottom = (unsigned long)(val & RB_TIME_VAL_MASK);
+	*msb = (unsigned long)(val >> RB_TIME_MSB_SHIFT);
+}
+
+static inline void rb_time_val_set(local_t *t, unsigned long val, unsigned long cnt)
+{
+	val = rb_time_val_cnt(val, cnt);
+	local_set(t, val);
+}
+
+static void rb_time_set(rb_time_t *t, u64 val)
+{
+	unsigned long cnt, top, bottom, msb;
+
+	rb_time_split(val, &top, &bottom, &msb);
+
+	/* Writes always succeed with a valid number even if it gets interrupted. */
+	do {
+		cnt = local_inc_return(&t->cnt);
+		rb_time_val_set(&t->top, top, cnt);
+		rb_time_val_set(&t->bottom, bottom, cnt);
+		rb_time_val_set(&t->msb, val >> RB_TIME_MSB_SHIFT, cnt);
+	} while (cnt != local_read(&t->cnt));
+}
+
+static inline bool
+rb_time_read_cmpxchg(local_t *l, unsigned long expect, unsigned long set)
+{
+	unsigned long ret;
+
+	ret = local_cmpxchg(l, expect, set);
+	return ret == expect;
+}
+
+#else /* 64 bits */
+
+/* local64_t always succeeds */
+
+static inline bool rb_time_read(rb_time_t *t, u64 *ret)
+{
+	*ret = local64_read(&t->time);
+	return true;
+}
+static void rb_time_set(rb_time_t *t, u64 val)
+{
+	local64_set(&t->time, val);
+}
+#endif
+
+/*
+ * Enable this to make sure that the event passed to
+ * ring_buffer_event_time_stamp() is not committed and also
+ * is on the buffer that it passed in.
+ */
+//#define RB_VERIFY_EVENT
+#ifdef RB_VERIFY_EVENT
+static struct list_head *rb_list_head(struct list_head *list);
+static void verify_event(struct ring_buffer_per_cpu *cpu_buffer,
+			 void *event)
+{
+	struct buffer_page *page = cpu_buffer->commit_page;
+	struct buffer_page *tail_page = READ_ONCE(cpu_buffer->tail_page);
+	struct list_head *next;
+	long commit, write;
+	unsigned long addr = (unsigned long)event;
+	bool done = false;
+	int stop = 0;
+
+	/* Make sure the event exists and is not committed yet */
+	do {
+		if (page == tail_page || WARN_ON_ONCE(stop++ > 100))
+			done = true;
+		commit = local_read(&page->page->commit);
+		write = local_read(&page->write);
+		if (addr >= (unsigned long)&page->page->data[commit] &&
+		    addr < (unsigned long)&page->page->data[write])
+			return;
+
+		next = rb_list_head(page->list.next);
+		page = list_entry(next, struct buffer_page, list);
+	} while (!done);
+	WARN_ON_ONCE(1);
+}
+#else
+static inline void verify_event(struct ring_buffer_per_cpu *cpu_buffer,
+			 void *event)
+{
+}
+#endif
+
+/*
+ * The absolute time stamp drops the 5 MSBs and some clocks may
+ * require them. The rb_fix_abs_ts() will take a previous full
+ * time stamp, and add the 5 MSB of that time stamp on to the
+ * saved absolute time stamp. Then they are compared in case of
+ * the unlikely event that the latest time stamp incremented
+ * the 5 MSB.
+ */
+static inline u64 rb_fix_abs_ts(u64 abs, u64 save_ts)
+{
+	if (save_ts & TS_MSB) {
+		abs |= save_ts & TS_MSB;
+		/* Check for overflow */
+		if (unlikely(abs < save_ts))
+			abs += 1ULL << 59;
+	}
+	return abs;
+}
+
+static inline u64 rb_time_stamp(struct trace_buffer *buffer);
+
+/**
+ * ring_buffer_event_time_stamp - return the event's current time stamp
+ * @buffer: The buffer that the event is on
+ * @event: the event to get the time stamp of
+ *
+ * Note, this must be called after @event is reserved, and before it is
+ * committed to the ring buffer. And must be called from the same
+ * context where the event was reserved (normal, softirq, irq, etc).
+ *
+ * Returns the time stamp associated with the current event.
+ * If the event has an extended time stamp, then that is used as
+ * the time stamp to return.
+ * In the highly unlikely case that the event was nested more than
+ * the max nesting, then the write_stamp of the buffer is returned,
+ * otherwise  current time is returned, but that really neither of
+ * the last two cases should ever happen.
+ */
+u64 ring_buffer_event_time_stamp(struct trace_buffer *buffer,
+				 struct ring_buffer_event *event)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[smp_processor_id()];
+	unsigned int nest;
+	u64 ts;
+
+	/* If the event includes an absolute time, then just use that */
+	if (event->type_len == RINGBUF_TYPE_TIME_STAMP) {
+		ts = rb_event_time_stamp(event);
+		return rb_fix_abs_ts(ts, cpu_buffer->tail_page->page->time_stamp);
+	}
+
+	nest = local_read(&cpu_buffer->committing);
+	verify_event(cpu_buffer, event);
+	if (WARN_ON_ONCE(!nest))
+		goto fail;
+
+	/* Read the current saved nesting level time stamp */
+	if (likely(--nest < MAX_NEST))
+		return cpu_buffer->event_stamp[nest];
+
+	/* Shouldn't happen, warn if it does */
+	WARN_ONCE(1, "nest (%d) greater than max", nest);
+
+ fail:
+	/* Can only fail on 32 bit */
+	if (!rb_time_read(&cpu_buffer->write_stamp, &ts))
+		/* Screw it, just read the current time */
+		ts = rb_time_stamp(cpu_buffer->buffer);
+
+	return ts;
+}
+
+/**
+ * ring_buffer_nr_pages - get the number of buffer pages in the ring buffer
+ * @buffer: The ring_buffer to get the number of pages from
+ * @cpu: The cpu of the ring_buffer to get the number of pages from
+ *
+ * Returns the number of pages used by a per_cpu buffer of the ring buffer.
+ */
+size_t ring_buffer_nr_pages(struct trace_buffer *buffer, int cpu)
+{
+	return buffer->buffers[cpu]->nr_pages;
+}
+
+/**
+ * ring_buffer_nr_dirty_pages - get the number of used pages in the ring buffer
+ * @buffer: The ring_buffer to get the number of pages from
+ * @cpu: The cpu of the ring_buffer to get the number of pages from
+ *
+ * Returns the number of pages that have content in the ring buffer.
+ */
+size_t ring_buffer_nr_dirty_pages(struct trace_buffer *buffer, int cpu)
+{
+	size_t read;
+	size_t lost;
+	size_t cnt;
+
+	read = local_read(&buffer->buffers[cpu]->pages_read);
+	lost = local_read(&buffer->buffers[cpu]->pages_lost);
+	cnt = local_read(&buffer->buffers[cpu]->pages_touched);
+
+	if (WARN_ON_ONCE(cnt < lost))
+		return 0;
+
+	cnt -= lost;
+
+	/* The reader can read an empty page, but not more than that */
+	if (cnt < read) {
+		WARN_ON_ONCE(read > cnt + 1);
+		return 0;
+	}
+
+	return cnt - read;
+}
+
+static __always_inline bool full_hit(struct trace_buffer *buffer, int cpu, int full)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+	size_t nr_pages;
+	size_t dirty;
+
+	nr_pages = cpu_buffer->nr_pages;
+	if (!nr_pages || !full)
+		return true;
+
+	/*
+	 * Add one as dirty will never equal nr_pages, as the sub-buffer
+	 * that the writer is on is not counted as dirty.
+	 * This is needed if "buffer_percent" is set to 100.
+	 */
+	dirty = ring_buffer_nr_dirty_pages(buffer, cpu) + 1;
+
+	return (dirty * 100) >= (full * nr_pages);
+}
+
+/*
+ * rb_wake_up_waiters - wake up tasks waiting for ring buffer input
+ *
+ * Schedules a delayed work to wake up any task that is blocked on the
+ * ring buffer waiters queue.
+ */
+static void rb_wake_up_waiters(struct irq_work *work)
+{
+	struct rb_irq_work *rbwork = container_of(work, struct rb_irq_work, work);
+
+	wake_up_all(&rbwork->waiters);
+	if (rbwork->full_waiters_pending || rbwork->wakeup_full) {
+		rbwork->wakeup_full = false;
+		rbwork->full_waiters_pending = false;
+		wake_up_all(&rbwork->full_waiters);
+	}
+}
+
+/**
+ * ring_buffer_wake_waiters - wake up any waiters on this ring buffer
+ * @buffer: The ring buffer to wake waiters on
+ *
+ * In the case of a file that represents a ring buffer is closing,
+ * it is prudent to wake up any waiters that are on this.
+ */
+void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct rb_irq_work *rbwork;
+
+	if (!buffer)
+		return;
+
+	if (cpu == RING_BUFFER_ALL_CPUS) {
+
+		/* Wake up individual ones too. One level recursion */
+		for_each_buffer_cpu(buffer, cpu)
+			ring_buffer_wake_waiters(buffer, cpu);
+
+		rbwork = &buffer->irq_work;
+	} else {
+		if (WARN_ON_ONCE(!buffer->buffers))
+			return;
+		if (WARN_ON_ONCE(cpu >= nr_cpu_ids))
+			return;
+
+		cpu_buffer = buffer->buffers[cpu];
+		/* The CPU buffer may not have been initialized yet */
+		if (!cpu_buffer)
+			return;
+		rbwork = &cpu_buffer->irq_work;
+	}
+
+	rbwork->wait_index++;
+	/* make sure the waiters see the new index */
+	smp_wmb();
+
+	/* This can be called in any context */
+	irq_work_queue(&rbwork->work);
+}
+
+/**
+ * ring_buffer_wait - wait for input to the ring buffer
+ * @buffer: buffer to wait on
+ * @cpu: the cpu buffer to wait on
+ * @full: wait until the percentage of pages are available, if @cpu != RING_BUFFER_ALL_CPUS
+ *
+ * If @cpu == RING_BUFFER_ALL_CPUS then the task will wake up as soon
+ * as data is added to any of the @buffer's cpu buffers. Otherwise
+ * it will wait for data to be added to a specific cpu buffer.
+ */
+int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	DEFINE_WAIT(wait);
+	struct rb_irq_work *work;
+	long wait_index;
+	int ret = 0;
+
+	/*
+	 * Depending on what the caller is waiting for, either any
+	 * data in any cpu buffer, or a specific buffer, put the
+	 * caller on the appropriate wait queue.
+	 */
+	if (cpu == RING_BUFFER_ALL_CPUS) {
+		work = &buffer->irq_work;
+		/* Full only makes sense on per cpu reads */
+		full = 0;
+	} else {
+		if (!cpumask_test_cpu(cpu, buffer->cpumask))
+			return -ENODEV;
+		cpu_buffer = buffer->buffers[cpu];
+		work = &cpu_buffer->irq_work;
+	}
+
+	wait_index = READ_ONCE(work->wait_index);
+
+	while (true) {
+		if (full)
+			prepare_to_wait(&work->full_waiters, &wait, TASK_INTERRUPTIBLE);
+		else
+			prepare_to_wait(&work->waiters, &wait, TASK_INTERRUPTIBLE);
+
+		/*
+		 * The events can happen in critical sections where
+		 * checking a work queue can cause deadlocks.
+		 * After adding a task to the queue, this flag is set
+		 * only to notify events to try to wake up the queue
+		 * using irq_work.
+		 *
+		 * We don't clear it even if the buffer is no longer
+		 * empty. The flag only causes the next event to run
+		 * irq_work to do the work queue wake up. The worse
+		 * that can happen if we race with !trace_empty() is that
+		 * an event will cause an irq_work to try to wake up
+		 * an empty queue.
+		 *
+		 * There's no reason to protect this flag either, as
+		 * the work queue and irq_work logic will do the necessary
+		 * synchronization for the wake ups. The only thing
+		 * that is necessary is that the wake up happens after
+		 * a task has been queued. It's OK for spurious wake ups.
+		 */
+		if (full)
+			work->full_waiters_pending = true;
+		else
+			work->waiters_pending = true;
+
+		if (signal_pending(current)) {
+			ret = -EINTR;
+			break;
+		}
+
+		if (cpu == RING_BUFFER_ALL_CPUS && !ring_buffer_empty(buffer))
+			break;
+
+		if (cpu != RING_BUFFER_ALL_CPUS &&
+		    !ring_buffer_empty_cpu(buffer, cpu)) {
+			unsigned long flags;
+			bool pagebusy;
+			bool done;
+
+			if (!full)
+				break;
+
+			raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+			pagebusy = cpu_buffer->reader_page == cpu_buffer->commit_page;
+			done = !pagebusy && full_hit(buffer, cpu, full);
+
+			if (!cpu_buffer->shortest_full ||
+			    cpu_buffer->shortest_full > full)
+				cpu_buffer->shortest_full = full;
+			raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+			if (done)
+				break;
+		}
+
+		schedule();
+
+		/* Make sure to see the new wait index */
+		smp_rmb();
+		if (wait_index != work->wait_index)
+			break;
+	}
+
+	if (full)
+		finish_wait(&work->full_waiters, &wait);
+	else
+		finish_wait(&work->waiters, &wait);
+
+	return ret;
+}
+
+/**
+ * ring_buffer_poll_wait - poll on buffer input
+ * @buffer: buffer to wait on
+ * @cpu: the cpu buffer to wait on
+ * @filp: the file descriptor
+ * @poll_table: The poll descriptor
+ * @full: wait until the percentage of pages are available, if @cpu != RING_BUFFER_ALL_CPUS
+ *
+ * If @cpu == RING_BUFFER_ALL_CPUS then the task will wake up as soon
+ * as data is added to any of the @buffer's cpu buffers. Otherwise
+ * it will wait for data to be added to a specific cpu buffer.
+ *
+ * Returns EPOLLIN | EPOLLRDNORM if data exists in the buffers,
+ * zero otherwise.
+ */
+__poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu,
+			  struct file *filp, poll_table *poll_table, int full)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct rb_irq_work *work;
+
+	if (cpu == RING_BUFFER_ALL_CPUS) {
+		work = &buffer->irq_work;
+		full = 0;
+	} else {
+		if (!cpumask_test_cpu(cpu, buffer->cpumask))
+			return -EINVAL;
+
+		cpu_buffer = buffer->buffers[cpu];
+		work = &cpu_buffer->irq_work;
+	}
+
+	if (full) {
+		poll_wait(filp, &work->full_waiters, poll_table);
+		work->full_waiters_pending = true;
+		if (!cpu_buffer->shortest_full ||
+		    cpu_buffer->shortest_full > full)
+			cpu_buffer->shortest_full = full;
+	} else {
+		poll_wait(filp, &work->waiters, poll_table);
+		work->waiters_pending = true;
+	}
+
+	/*
+	 * There's a tight race between setting the waiters_pending and
+	 * checking if the ring buffer is empty.  Once the waiters_pending bit
+	 * is set, the next event will wake the task up, but we can get stuck
+	 * if there's only a single event in.
+	 *
+	 * FIXME: Ideally, we need a memory barrier on the writer side as well,
+	 * but adding a memory barrier to all events will cause too much of a
+	 * performance hit in the fast path.  We only need a memory barrier when
+	 * the buffer goes from empty to having content.  But as this race is
+	 * extremely small, and it's not a problem if another event comes in, we
+	 * will fix it later.
+	 */
+	smp_mb();
+
+	if (full)
+		return full_hit(buffer, cpu, full) ? EPOLLIN | EPOLLRDNORM : 0;
+
+	if ((cpu == RING_BUFFER_ALL_CPUS && !ring_buffer_empty(buffer)) ||
+	    (cpu != RING_BUFFER_ALL_CPUS && !ring_buffer_empty_cpu(buffer, cpu)))
+		return EPOLLIN | EPOLLRDNORM;
+	return 0;
+}
+
+/* buffer may be either ring_buffer or ring_buffer_per_cpu */
+#define RB_WARN_ON(b, cond)						\
+	({								\
+		int _____ret = unlikely(cond);				\
+		if (_____ret) {						\
+			if (__same_type(*(b), struct ring_buffer_per_cpu)) { \
+				struct ring_buffer_per_cpu *__b =	\
+					(void *)b;			\
+				atomic_inc(&__b->buffer->record_disabled); \
+			} else						\
+				atomic_inc(&b->record_disabled);	\
+			WARN_ON(1);					\
+		}							\
+		_____ret;						\
+	})
+
+/* Up this if you want to test the TIME_EXTENTS and normalization */
+#define DEBUG_SHIFT 0
+
+static inline u64 rb_time_stamp(struct trace_buffer *buffer)
+{
+	u64 ts;
+
+	/* Skip retpolines :-( */
+	if (IS_ENABLED(CONFIG_RETPOLINE) && likely(buffer->clock == trace_clock_local))
+		ts = trace_clock_local();
+	else
+		ts = buffer->clock();
+
+	/* shift to debug/test normalization and TIME_EXTENTS */
+	return ts << DEBUG_SHIFT;
+}
+
+u64 ring_buffer_time_stamp(struct trace_buffer *buffer)
+{
+	u64 time;
+
+	preempt_disable_notrace();
+	time = rb_time_stamp(buffer);
+	preempt_enable_notrace();
+
+	return time;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_time_stamp);
+
+void ring_buffer_normalize_time_stamp(struct trace_buffer *buffer,
+				      int cpu, u64 *ts)
+{
+	/* Just stupid testing the normalize function and deltas */
+	*ts >>= DEBUG_SHIFT;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_normalize_time_stamp);
+
+/*
+ * Making the ring buffer lockless makes things tricky.
+ * Although writes only happen on the CPU that they are on,
+ * and they only need to worry about interrupts. Reads can
+ * happen on any CPU.
+ *
+ * The reader page is always off the ring buffer, but when the
+ * reader finishes with a page, it needs to swap its page with
+ * a new one from the buffer. The reader needs to take from
+ * the head (writes go to the tail). But if a writer is in overwrite
+ * mode and wraps, it must push the head page forward.
+ *
+ * Here lies the problem.
+ *
+ * The reader must be careful to replace only the head page, and
+ * not another one. As described at the top of the file in the
+ * ASCII art, the reader sets its old page to point to the next
+ * page after head. It then sets the page after head to point to
+ * the old reader page. But if the writer moves the head page
+ * during this operation, the reader could end up with the tail.
+ *
+ * We use cmpxchg to help prevent this race. We also do something
+ * special with the page before head. We set the LSB to 1.
+ *
+ * When the writer must push the page forward, it will clear the
+ * bit that points to the head page, move the head, and then set
+ * the bit that points to the new head page.
+ *
+ * We also don't want an interrupt coming in and moving the head
+ * page on another writer. Thus we use the second LSB to catch
+ * that too. Thus:
+ *
+ * head->list->prev->next        bit 1          bit 0
+ *                              -------        -------
+ * Normal page                     0              0
+ * Points to head page             0              1
+ * New head page                   1              0
+ *
+ * Note we can not trust the prev pointer of the head page, because:
+ *
+ * +----+       +-----+        +-----+
+ * |    |------>|  T  |---X--->|  N  |
+ * |    |<------|     |        |     |
+ * +----+       +-----+        +-----+
+ *   ^                           ^ |
+ *   |          +-----+          | |
+ *   +----------|  R  |----------+ |
+ *              |     |<-----------+
+ *              +-----+
+ *
+ * Key:  ---X-->  HEAD flag set in pointer
+ *         T      Tail page
+ *         R      Reader page
+ *         N      Next page
+ *
+ * (see __rb_reserve_next() to see where this happens)
+ *
+ *  What the above shows is that the reader just swapped out
+ *  the reader page with a page in the buffer, but before it
+ *  could make the new header point back to the new page added
+ *  it was preempted by a writer. The writer moved forward onto
+ *  the new page added by the reader and is about to move forward
+ *  again.
+ *
+ *  You can see, it is legitimate for the previous pointer of
+ *  the head (or any page) not to point back to itself. But only
+ *  temporarily.
+ */
+
+#define RB_PAGE_NORMAL		0UL
+#define RB_PAGE_HEAD		1UL
+#define RB_PAGE_UPDATE		2UL
+
+
+#define RB_FLAG_MASK		3UL
+
+/* PAGE_MOVED is not part of the mask */
+#define RB_PAGE_MOVED		4UL
+
+/*
+ * rb_list_head - remove any bit
+ */
+static struct list_head *rb_list_head(struct list_head *list)
+{
+	unsigned long val = (unsigned long)list;
+
+	return (struct list_head *)(val & ~RB_FLAG_MASK);
+}
+
+/*
+ * rb_is_head_page - test if the given page is the head page
+ *
+ * Because the reader may move the head_page pointer, we can
+ * not trust what the head page is (it may be pointing to
+ * the reader page). But if the next page is a header page,
+ * its flags will be non zero.
+ */
+static inline int
+rb_is_head_page(struct buffer_page *page, struct list_head *list)
+{
+	unsigned long val;
+
+	val = (unsigned long)list->next;
+
+	if ((val & ~RB_FLAG_MASK) != (unsigned long)&page->list)
+		return RB_PAGE_MOVED;
+
+	return val & RB_FLAG_MASK;
+}
+
+/*
+ * rb_is_reader_page
+ *
+ * The unique thing about the reader page, is that, if the
+ * writer is ever on it, the previous pointer never points
+ * back to the reader page.
+ */
+static bool rb_is_reader_page(struct buffer_page *page)
+{
+	struct list_head *list = page->list.prev;
+
+	return rb_list_head(list->next) != &page->list;
+}
+
+/*
+ * rb_set_list_to_head - set a list_head to be pointing to head.
+ */
+static void rb_set_list_to_head(struct list_head *list)
+{
+	unsigned long *ptr;
+
+	ptr = (unsigned long *)&list->next;
+	*ptr |= RB_PAGE_HEAD;
+	*ptr &= ~RB_PAGE_UPDATE;
+}
+
+/*
+ * rb_head_page_activate - sets up head page
+ */
+static void rb_head_page_activate(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct buffer_page *head;
+
+	head = cpu_buffer->head_page;
+	if (!head)
+		return;
+
+	/*
+	 * Set the previous list pointer to have the HEAD flag.
+	 */
+	rb_set_list_to_head(head->list.prev);
+}
+
+static void rb_list_head_clear(struct list_head *list)
+{
+	unsigned long *ptr = (unsigned long *)&list->next;
+
+	*ptr &= ~RB_FLAG_MASK;
+}
+
+/*
+ * rb_head_page_deactivate - clears head page ptr (for free list)
+ */
+static void
+rb_head_page_deactivate(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct list_head *hd;
+
+	/* Go through the whole list and clear any pointers found. */
+	rb_list_head_clear(cpu_buffer->pages);
+
+	list_for_each(hd, cpu_buffer->pages)
+		rb_list_head_clear(hd);
+}
+
+static int rb_head_page_set(struct ring_buffer_per_cpu *cpu_buffer,
+			    struct buffer_page *head,
+			    struct buffer_page *prev,
+			    int old_flag, int new_flag)
+{
+	struct list_head *list;
+	unsigned long val = (unsigned long)&head->list;
+	unsigned long ret;
+
+	list = &prev->list;
+
+	val &= ~RB_FLAG_MASK;
+
+	ret = cmpxchg((unsigned long *)&list->next,
+		      val | old_flag, val | new_flag);
+
+	/* check if the reader took the page */
+	if ((ret & ~RB_FLAG_MASK) != val)
+		return RB_PAGE_MOVED;
+
+	return ret & RB_FLAG_MASK;
+}
+
+static int rb_head_page_set_update(struct ring_buffer_per_cpu *cpu_buffer,
+				   struct buffer_page *head,
+				   struct buffer_page *prev,
+				   int old_flag)
+{
+	return rb_head_page_set(cpu_buffer, head, prev,
+				old_flag, RB_PAGE_UPDATE);
+}
+
+static int rb_head_page_set_head(struct ring_buffer_per_cpu *cpu_buffer,
+				 struct buffer_page *head,
+				 struct buffer_page *prev,
+				 int old_flag)
+{
+	return rb_head_page_set(cpu_buffer, head, prev,
+				old_flag, RB_PAGE_HEAD);
+}
+
+static int rb_head_page_set_normal(struct ring_buffer_per_cpu *cpu_buffer,
+				   struct buffer_page *head,
+				   struct buffer_page *prev,
+				   int old_flag)
+{
+	return rb_head_page_set(cpu_buffer, head, prev,
+				old_flag, RB_PAGE_NORMAL);
+}
+
+static inline void rb_inc_page(struct buffer_page **bpage)
+{
+	struct list_head *p = rb_list_head((*bpage)->list.next);
+
+	*bpage = list_entry(p, struct buffer_page, list);
+}
+
+static struct buffer_page *
+rb_set_head_page(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct buffer_page *head;
+	struct buffer_page *page;
+	struct list_head *list;
+	int i;
+
+	if (RB_WARN_ON(cpu_buffer, !cpu_buffer->head_page))
+		return NULL;
+
+	/* sanity check */
+	list = cpu_buffer->pages;
+	if (RB_WARN_ON(cpu_buffer, rb_list_head(list->prev->next) != list))
+		return NULL;
+
+	page = head = cpu_buffer->head_page;
+	/*
+	 * It is possible that the writer moves the header behind
+	 * where we started, and we miss in one loop.
+	 * A second loop should grab the header, but we'll do
+	 * three loops just because I'm paranoid.
+	 */
+	for (i = 0; i < 3; i++) {
+		do {
+			if (rb_is_head_page(page, page->list.prev)) {
+				cpu_buffer->head_page = page;
+				return page;
+			}
+			rb_inc_page(&page);
+		} while (page != head);
+	}
+
+	RB_WARN_ON(cpu_buffer, 1);
+
+	return NULL;
+}
+
+static int rb_head_page_replace(struct buffer_page *old,
+				struct buffer_page *new)
+{
+	unsigned long *ptr = (unsigned long *)&old->list.prev->next;
+	unsigned long val;
+	unsigned long ret;
+
+	val = *ptr & ~RB_FLAG_MASK;
+	val |= RB_PAGE_HEAD;
+
+	ret = cmpxchg(ptr, val, (unsigned long)&new->list);
+
+	return ret == val;
+}
+
+/*
+ * rb_tail_page_update - move the tail page forward
+ */
+static void rb_tail_page_update(struct ring_buffer_per_cpu *cpu_buffer,
+			       struct buffer_page *tail_page,
+			       struct buffer_page *next_page)
+{
+	unsigned long old_entries;
+	unsigned long old_write;
+
+	/*
+	 * The tail page now needs to be moved forward.
+	 *
+	 * We need to reset the tail page, but without messing
+	 * with possible erasing of data brought in by interrupts
+	 * that have moved the tail page and are currently on it.
+	 *
+	 * We add a counter to the write field to denote this.
+	 */
+	old_write = local_add_return(RB_WRITE_INTCNT, &next_page->write);
+	old_entries = local_add_return(RB_WRITE_INTCNT, &next_page->entries);
+
+	local_inc(&cpu_buffer->pages_touched);
+	/*
+	 * Just make sure we have seen our old_write and synchronize
+	 * with any interrupts that come in.
+	 */
+	barrier();
+
+	/*
+	 * If the tail page is still the same as what we think
+	 * it is, then it is up to us to update the tail
+	 * pointer.
+	 */
+	if (tail_page == READ_ONCE(cpu_buffer->tail_page)) {
+		/* Zero the write counter */
+		unsigned long val = old_write & ~RB_WRITE_MASK;
+		unsigned long eval = old_entries & ~RB_WRITE_MASK;
+
+		/*
+		 * This will only succeed if an interrupt did
+		 * not come in and change it. In which case, we
+		 * do not want to modify it.
+		 *
+		 * We add (void) to let the compiler know that we do not care
+		 * about the return value of these functions. We use the
+		 * cmpxchg to only update if an interrupt did not already
+		 * do it for us. If the cmpxchg fails, we don't care.
+		 */
+		(void)local_cmpxchg(&next_page->write, old_write, val);
+		(void)local_cmpxchg(&next_page->entries, old_entries, eval);
+
+		/*
+		 * No need to worry about races with clearing out the commit.
+		 * it only can increment when a commit takes place. But that
+		 * only happens in the outer most nested commit.
+		 */
+		local_set(&next_page->page->commit, 0);
+
+		/* Again, either we update tail_page or an interrupt does */
+		(void)cmpxchg(&cpu_buffer->tail_page, tail_page, next_page);
+	}
+}
+
+static int rb_check_bpage(struct ring_buffer_per_cpu *cpu_buffer,
+			  struct buffer_page *bpage)
+{
+	unsigned long val = (unsigned long)bpage;
+
+	if (RB_WARN_ON(cpu_buffer, val & RB_FLAG_MASK))
+		return 1;
+
+	return 0;
+}
+
+/**
+ * rb_check_pages - integrity check of buffer pages
+ * @cpu_buffer: CPU buffer with pages to test
+ *
+ * As a safety measure we check to make sure the data pages have not
+ * been corrupted.
+ */
+static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct list_head *head = rb_list_head(cpu_buffer->pages);
+	struct list_head *tmp;
+
+	if (RB_WARN_ON(cpu_buffer,
+			rb_list_head(rb_list_head(head->next)->prev) != head))
+		return -1;
+
+	if (RB_WARN_ON(cpu_buffer,
+			rb_list_head(rb_list_head(head->prev)->next) != head))
+		return -1;
+
+	for (tmp = rb_list_head(head->next); tmp != head; tmp = rb_list_head(tmp->next)) {
+		if (RB_WARN_ON(cpu_buffer,
+				rb_list_head(rb_list_head(tmp->next)->prev) != tmp))
+			return -1;
+
+		if (RB_WARN_ON(cpu_buffer,
+				rb_list_head(rb_list_head(tmp->prev)->next) != tmp))
+			return -1;
+	}
+
+	return 0;
+}
+
+static int __rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
+		long nr_pages, struct list_head *pages)
+{
+	struct buffer_page *bpage, *tmp;
+	bool user_thread = current->mm != NULL;
+	gfp_t mflags;
+	long i;
+
+	/*
+	 * Check if the available memory is there first.
+	 * Note, si_mem_available() only gives us a rough estimate of available
+	 * memory. It may not be accurate. But we don't care, we just want
+	 * to prevent doing any allocation when it is obvious that it is
+	 * not going to succeed.
+	 */
+	i = si_mem_available();
+	if (i < nr_pages)
+		return -ENOMEM;
+
+	/*
+	 * __GFP_RETRY_MAYFAIL flag makes sure that the allocation fails
+	 * gracefully without invoking oom-killer and the system is not
+	 * destabilized.
+	 */
+	mflags = GFP_KERNEL | __GFP_RETRY_MAYFAIL;
+
+	/*
+	 * If a user thread allocates too much, and si_mem_available()
+	 * reports there's enough memory, even though there is not.
+	 * Make sure the OOM killer kills this thread. This can happen
+	 * even with RETRY_MAYFAIL because another task may be doing
+	 * an allocation after this task has taken all memory.
+	 * This is the task the OOM killer needs to take out during this
+	 * loop, even if it was triggered by an allocation somewhere else.
+	 */
+	if (user_thread)
+		set_current_oom_origin();
+	for (i = 0; i < nr_pages; i++) {
+		struct page *page;
+
+		bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
+				    mflags, cpu_to_node(cpu_buffer->cpu));
+		if (!bpage)
+			goto free_pages;
+
+		rb_check_bpage(cpu_buffer, bpage);
+
+		list_add(&bpage->list, pages);
+
+		page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu), mflags, 0);
+		if (!page)
+			goto free_pages;
+		bpage->page = page_address(page);
+		rb_init_page(bpage->page);
+
+		if (user_thread && fatal_signal_pending(current))
+			goto free_pages;
+	}
+	if (user_thread)
+		clear_current_oom_origin();
+
+	return 0;
+
+free_pages:
+	list_for_each_entry_safe(bpage, tmp, pages, list) {
+		list_del_init(&bpage->list);
+		free_buffer_page(bpage);
+	}
+	if (user_thread)
+		clear_current_oom_origin();
+
+	return -ENOMEM;
+}
+
+static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
+			     unsigned long nr_pages)
+{
+	LIST_HEAD(pages);
+
+	WARN_ON(!nr_pages);
+
+	if (__rb_allocate_pages(cpu_buffer, nr_pages, &pages))
+		return -ENOMEM;
+
+	/*
+	 * The ring buffer page list is a circular list that does not
+	 * start and end with a list head. All page list items point to
+	 * other pages.
+	 */
+	cpu_buffer->pages = pages.next;
+	list_del(&pages);
+
+	cpu_buffer->nr_pages = nr_pages;
+
+	rb_check_pages(cpu_buffer);
+
+	return 0;
+}
+
+static struct ring_buffer_per_cpu *
+rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct buffer_page *bpage;
+	struct page *page;
+	int ret;
+
+	cpu_buffer = kzalloc_node(ALIGN(sizeof(*cpu_buffer), cache_line_size()),
+				  GFP_KERNEL, cpu_to_node(cpu));
+	if (!cpu_buffer)
+		return NULL;
+
+	cpu_buffer->cpu = cpu;
+	cpu_buffer->buffer = buffer;
+	raw_spin_lock_init(&cpu_buffer->reader_lock);
+	lockdep_set_class(&cpu_buffer->reader_lock, buffer->reader_lock_key);
+	cpu_buffer->lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+	INIT_WORK(&cpu_buffer->update_pages_work, update_pages_handler);
+	init_completion(&cpu_buffer->update_done);
+	init_irq_work(&cpu_buffer->irq_work.work, rb_wake_up_waiters);
+	init_waitqueue_head(&cpu_buffer->irq_work.waiters);
+	init_waitqueue_head(&cpu_buffer->irq_work.full_waiters);
+
+	bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
+			    GFP_KERNEL, cpu_to_node(cpu));
+	if (!bpage)
+		goto fail_free_buffer;
+
+	rb_check_bpage(cpu_buffer, bpage);
+
+	cpu_buffer->reader_page = bpage;
+	page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, 0);
+	if (!page)
+		goto fail_free_reader;
+	bpage->page = page_address(page);
+	rb_init_page(bpage->page);
+
+	INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
+	INIT_LIST_HEAD(&cpu_buffer->new_pages);
+
+	ret = rb_allocate_pages(cpu_buffer, nr_pages);
+	if (ret < 0)
+		goto fail_free_reader;
+
+	cpu_buffer->head_page
+		= list_entry(cpu_buffer->pages, struct buffer_page, list);
+	cpu_buffer->tail_page = cpu_buffer->commit_page = cpu_buffer->head_page;
+
+	rb_head_page_activate(cpu_buffer);
+
+	return cpu_buffer;
+
+ fail_free_reader:
+	free_buffer_page(cpu_buffer->reader_page);
+
+ fail_free_buffer:
+	kfree(cpu_buffer);
+	return NULL;
+}
+
+static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct list_head *head = cpu_buffer->pages;
+	struct buffer_page *bpage, *tmp;
+
+	irq_work_sync(&cpu_buffer->irq_work.work);
+
+	free_buffer_page(cpu_buffer->reader_page);
+
+	if (head) {
+		rb_head_page_deactivate(cpu_buffer);
+
+		list_for_each_entry_safe(bpage, tmp, head, list) {
+			list_del_init(&bpage->list);
+			free_buffer_page(bpage);
+		}
+		bpage = list_entry(head, struct buffer_page, list);
+		free_buffer_page(bpage);
+	}
+
+	free_page((unsigned long)cpu_buffer->free_page);
+
+	kfree(cpu_buffer);
+}
+
+/**
+ * __ring_buffer_alloc - allocate a new ring_buffer
+ * @size: the size in bytes per cpu that is needed.
+ * @flags: attributes to set for the ring buffer.
+ * @key: ring buffer reader_lock_key.
+ *
+ * Currently the only flag that is available is the RB_FL_OVERWRITE
+ * flag. This flag means that the buffer will overwrite old data
+ * when the buffer wraps. If this flag is not set, the buffer will
+ * drop data when the tail hits the head.
+ */
+struct trace_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
+					struct lock_class_key *key)
+{
+	struct trace_buffer *buffer;
+	long nr_pages;
+	int bsize;
+	int cpu;
+	int ret;
+
+	/* keep it in its own cache line */
+	buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
+			 GFP_KERNEL);
+	if (!buffer)
+		return NULL;
+
+	if (!zalloc_cpumask_var(&buffer->cpumask, GFP_KERNEL))
+		goto fail_free_buffer;
+
+	nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+	buffer->flags = flags;
+	buffer->clock = trace_clock_local;
+	buffer->reader_lock_key = key;
+
+	init_irq_work(&buffer->irq_work.work, rb_wake_up_waiters);
+	init_waitqueue_head(&buffer->irq_work.waiters);
+
+	/* need at least two pages */
+	if (nr_pages < 2)
+		nr_pages = 2;
+
+	buffer->cpus = nr_cpu_ids;
+
+	bsize = sizeof(void *) * nr_cpu_ids;
+	buffer->buffers = kzalloc(ALIGN(bsize, cache_line_size()),
+				  GFP_KERNEL);
+	if (!buffer->buffers)
+		goto fail_free_cpumask;
+
+	cpu = raw_smp_processor_id();
+	cpumask_set_cpu(cpu, buffer->cpumask);
+	buffer->buffers[cpu] = rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
+	if (!buffer->buffers[cpu])
+		goto fail_free_buffers;
+
+	ret = cpuhp_state_add_instance(CPUHP_TRACE_RB_PREPARE, &buffer->node);
+	if (ret < 0)
+		goto fail_free_buffers;
+
+	mutex_init(&buffer->mutex);
+
+	return buffer;
+
+ fail_free_buffers:
+	for_each_buffer_cpu(buffer, cpu) {
+		if (buffer->buffers[cpu])
+			rb_free_cpu_buffer(buffer->buffers[cpu]);
+	}
+	kfree(buffer->buffers);
+
+ fail_free_cpumask:
+	free_cpumask_var(buffer->cpumask);
+
+ fail_free_buffer:
+	kfree(buffer);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(__ring_buffer_alloc);
+
+/**
+ * ring_buffer_free - free a ring buffer.
+ * @buffer: the buffer to free.
+ */
+void
+ring_buffer_free(struct trace_buffer *buffer)
+{
+	int cpu;
+
+	cpuhp_state_remove_instance(CPUHP_TRACE_RB_PREPARE, &buffer->node);
+
+	irq_work_sync(&buffer->irq_work.work);
+
+	for_each_buffer_cpu(buffer, cpu)
+		rb_free_cpu_buffer(buffer->buffers[cpu]);
+
+	kfree(buffer->buffers);
+	free_cpumask_var(buffer->cpumask);
+
+	kfree(buffer);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_free);
+
+void ring_buffer_set_clock(struct trace_buffer *buffer,
+			   u64 (*clock)(void))
+{
+	buffer->clock = clock;
+}
+
+void ring_buffer_set_time_stamp_abs(struct trace_buffer *buffer, bool abs)
+{
+	buffer->time_stamp_abs = abs;
+}
+
+bool ring_buffer_time_stamp_abs(struct trace_buffer *buffer)
+{
+	return buffer->time_stamp_abs;
+}
+
+static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer);
+
+static inline unsigned long rb_page_entries(struct buffer_page *bpage)
+{
+	return local_read(&bpage->entries) & RB_WRITE_MASK;
+}
+
+static inline unsigned long rb_page_write(struct buffer_page *bpage)
+{
+	return local_read(&bpage->write) & RB_WRITE_MASK;
+}
+
+static int
+rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned long nr_pages)
+{
+	struct list_head *tail_page, *to_remove, *next_page;
+	struct buffer_page *to_remove_page, *tmp_iter_page;
+	struct buffer_page *last_page, *first_page;
+	unsigned long nr_removed;
+	unsigned long head_bit;
+	int page_entries;
+
+	head_bit = 0;
+
+	raw_spin_lock_irq(&cpu_buffer->reader_lock);
+	atomic_inc(&cpu_buffer->record_disabled);
+	/*
+	 * We don't race with the readers since we have acquired the reader
+	 * lock. We also don't race with writers after disabling recording.
+	 * This makes it easy to figure out the first and the last page to be
+	 * removed from the list. We unlink all the pages in between including
+	 * the first and last pages. This is done in a busy loop so that we
+	 * lose the least number of traces.
+	 * The pages are freed after we restart recording and unlock readers.
+	 */
+	tail_page = &cpu_buffer->tail_page->list;
+
+	/*
+	 * tail page might be on reader page, we remove the next page
+	 * from the ring buffer
+	 */
+	if (cpu_buffer->tail_page == cpu_buffer->reader_page)
+		tail_page = rb_list_head(tail_page->next);
+	to_remove = tail_page;
+
+	/* start of pages to remove */
+	first_page = list_entry(rb_list_head(to_remove->next),
+				struct buffer_page, list);
+
+	for (nr_removed = 0; nr_removed < nr_pages; nr_removed++) {
+		to_remove = rb_list_head(to_remove)->next;
+		head_bit |= (unsigned long)to_remove & RB_PAGE_HEAD;
+	}
+	/* Read iterators need to reset themselves when some pages removed */
+	cpu_buffer->pages_removed += nr_removed;
+
+	next_page = rb_list_head(to_remove)->next;
+
+	/*
+	 * Now we remove all pages between tail_page and next_page.
+	 * Make sure that we have head_bit value preserved for the
+	 * next page
+	 */
+	tail_page->next = (struct list_head *)((unsigned long)next_page |
+						head_bit);
+	next_page = rb_list_head(next_page);
+	next_page->prev = tail_page;
+
+	/* make sure pages points to a valid page in the ring buffer */
+	cpu_buffer->pages = next_page;
+
+	/* update head page */
+	if (head_bit)
+		cpu_buffer->head_page = list_entry(next_page,
+						struct buffer_page, list);
+
+	/* pages are removed, resume tracing and then free the pages */
+	atomic_dec(&cpu_buffer->record_disabled);
+	raw_spin_unlock_irq(&cpu_buffer->reader_lock);
+
+	RB_WARN_ON(cpu_buffer, list_empty(cpu_buffer->pages));
+
+	/* last buffer page to remove */
+	last_page = list_entry(rb_list_head(to_remove), struct buffer_page,
+				list);
+	tmp_iter_page = first_page;
+
+	do {
+		cond_resched();
+
+		to_remove_page = tmp_iter_page;
+		rb_inc_page(&tmp_iter_page);
+
+		/* update the counters */
+		page_entries = rb_page_entries(to_remove_page);
+		if (page_entries) {
+			/*
+			 * If something was added to this page, it was full
+			 * since it is not the tail page. So we deduct the
+			 * bytes consumed in ring buffer from here.
+			 * Increment overrun to account for the lost events.
+			 */
+			local_add(page_entries, &cpu_buffer->overrun);
+			local_sub(rb_page_commit(to_remove_page), &cpu_buffer->entries_bytes);
+			local_inc(&cpu_buffer->pages_lost);
+		}
+
+		/*
+		 * We have already removed references to this list item, just
+		 * free up the buffer_page and its page
+		 */
+		free_buffer_page(to_remove_page);
+		nr_removed--;
+
+	} while (to_remove_page != last_page);
+
+	RB_WARN_ON(cpu_buffer, nr_removed);
+
+	return nr_removed == 0;
+}
+
+static int
+rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct list_head *pages = &cpu_buffer->new_pages;
+	int retries, success;
+
+	raw_spin_lock_irq(&cpu_buffer->reader_lock);
+	/*
+	 * We are holding the reader lock, so the reader page won't be swapped
+	 * in the ring buffer. Now we are racing with the writer trying to
+	 * move head page and the tail page.
+	 * We are going to adapt the reader page update process where:
+	 * 1. We first splice the start and end of list of new pages between
+	 *    the head page and its previous page.
+	 * 2. We cmpxchg the prev_page->next to point from head page to the
+	 *    start of new pages list.
+	 * 3. Finally, we update the head->prev to the end of new list.
+	 *
+	 * We will try this process 10 times, to make sure that we don't keep
+	 * spinning.
+	 */
+	retries = 10;
+	success = 0;
+	while (retries--) {
+		struct list_head *head_page, *prev_page, *r;
+		struct list_head *last_page, *first_page;
+		struct list_head *head_page_with_bit;
+
+		head_page = &rb_set_head_page(cpu_buffer)->list;
+		if (!head_page)
+			break;
+		prev_page = head_page->prev;
+
+		first_page = pages->next;
+		last_page  = pages->prev;
+
+		head_page_with_bit = (struct list_head *)
+				     ((unsigned long)head_page | RB_PAGE_HEAD);
+
+		last_page->next = head_page_with_bit;
+		first_page->prev = prev_page;
+
+		r = cmpxchg(&prev_page->next, head_page_with_bit, first_page);
+
+		if (r == head_page_with_bit) {
+			/*
+			 * yay, we replaced the page pointer to our new list,
+			 * now, we just have to update to head page's prev
+			 * pointer to point to end of list
+			 */
+			head_page->prev = last_page;
+			success = 1;
+			break;
+		}
+	}
+
+	if (success)
+		INIT_LIST_HEAD(pages);
+	/*
+	 * If we weren't successful in adding in new pages, warn and stop
+	 * tracing
+	 */
+	RB_WARN_ON(cpu_buffer, !success);
+	raw_spin_unlock_irq(&cpu_buffer->reader_lock);
+
+	/* free pages if they weren't inserted */
+	if (!success) {
+		struct buffer_page *bpage, *tmp;
+		list_for_each_entry_safe(bpage, tmp, &cpu_buffer->new_pages,
+					 list) {
+			list_del_init(&bpage->list);
+			free_buffer_page(bpage);
+		}
+	}
+	return success;
+}
+
+static void rb_update_pages(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	int success;
+
+	if (cpu_buffer->nr_pages_to_update > 0)
+		success = rb_insert_pages(cpu_buffer);
+	else
+		success = rb_remove_pages(cpu_buffer,
+					-cpu_buffer->nr_pages_to_update);
+
+	if (success)
+		cpu_buffer->nr_pages += cpu_buffer->nr_pages_to_update;
+}
+
+static void update_pages_handler(struct work_struct *work)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = container_of(work,
+			struct ring_buffer_per_cpu, update_pages_work);
+	rb_update_pages(cpu_buffer);
+	complete(&cpu_buffer->update_done);
+}
+
+/**
+ * ring_buffer_resize - resize the ring buffer
+ * @buffer: the buffer to resize.
+ * @size: the new size.
+ * @cpu_id: the cpu buffer to resize
+ *
+ * Minimum size is 2 * BUF_PAGE_SIZE.
+ *
+ * Returns 0 on success and < 0 on failure.
+ */
+int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
+			int cpu_id)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long nr_pages;
+	int cpu, err;
+
+	/*
+	 * Always succeed at resizing a non-existent buffer:
+	 */
+	if (!buffer)
+		return 0;
+
+	/* Make sure the requested buffer exists */
+	if (cpu_id != RING_BUFFER_ALL_CPUS &&
+	    !cpumask_test_cpu(cpu_id, buffer->cpumask))
+		return 0;
+
+	nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+
+	/* we need a minimum of two pages */
+	if (nr_pages < 2)
+		nr_pages = 2;
+
+	/* prevent another thread from changing buffer sizes */
+	mutex_lock(&buffer->mutex);
+	atomic_inc(&buffer->resizing);
+
+	if (cpu_id == RING_BUFFER_ALL_CPUS) {
+		/*
+		 * Don't succeed if resizing is disabled, as a reader might be
+		 * manipulating the ring buffer and is expecting a sane state while
+		 * this is true.
+		 */
+		for_each_buffer_cpu(buffer, cpu) {
+			cpu_buffer = buffer->buffers[cpu];
+			if (atomic_read(&cpu_buffer->resize_disabled)) {
+				err = -EBUSY;
+				goto out_err_unlock;
+			}
+		}
+
+		/* calculate the pages to update */
+		for_each_buffer_cpu(buffer, cpu) {
+			cpu_buffer = buffer->buffers[cpu];
+
+			cpu_buffer->nr_pages_to_update = nr_pages -
+							cpu_buffer->nr_pages;
+			/*
+			 * nothing more to do for removing pages or no update
+			 */
+			if (cpu_buffer->nr_pages_to_update <= 0)
+				continue;
+			/*
+			 * to add pages, make sure all new pages can be
+			 * allocated without receiving ENOMEM
+			 */
+			INIT_LIST_HEAD(&cpu_buffer->new_pages);
+			if (__rb_allocate_pages(cpu_buffer, cpu_buffer->nr_pages_to_update,
+						&cpu_buffer->new_pages)) {
+				/* not enough memory for new pages */
+				err = -ENOMEM;
+				goto out_err;
+			}
+
+			cond_resched();
+		}
+
+		cpus_read_lock();
+		/*
+		 * Fire off all the required work handlers
+		 * We can't schedule on offline CPUs, but it's not necessary
+		 * since we can change their buffer sizes without any race.
+		 */
+		for_each_buffer_cpu(buffer, cpu) {
+			cpu_buffer = buffer->buffers[cpu];
+			if (!cpu_buffer->nr_pages_to_update)
+				continue;
+
+			/* Can't run something on an offline CPU. */
+			if (!cpu_online(cpu)) {
+				rb_update_pages(cpu_buffer);
+				cpu_buffer->nr_pages_to_update = 0;
+			} else {
+				schedule_work_on(cpu,
+						&cpu_buffer->update_pages_work);
+			}
+		}
+
+		/* wait for all the updates to complete */
+		for_each_buffer_cpu(buffer, cpu) {
+			cpu_buffer = buffer->buffers[cpu];
+			if (!cpu_buffer->nr_pages_to_update)
+				continue;
+
+			if (cpu_online(cpu))
+				wait_for_completion(&cpu_buffer->update_done);
+			cpu_buffer->nr_pages_to_update = 0;
+		}
+
+		cpus_read_unlock();
+	} else {
+		cpu_buffer = buffer->buffers[cpu_id];
+
+		if (nr_pages == cpu_buffer->nr_pages)
+			goto out;
+
+		/*
+		 * Don't succeed if resizing is disabled, as a reader might be
+		 * manipulating the ring buffer and is expecting a sane state while
+		 * this is true.
+		 */
+		if (atomic_read(&cpu_buffer->resize_disabled)) {
+			err = -EBUSY;
+			goto out_err_unlock;
+		}
+
+		cpu_buffer->nr_pages_to_update = nr_pages -
+						cpu_buffer->nr_pages;
+
+		INIT_LIST_HEAD(&cpu_buffer->new_pages);
+		if (cpu_buffer->nr_pages_to_update > 0 &&
+			__rb_allocate_pages(cpu_buffer, cpu_buffer->nr_pages_to_update,
+					    &cpu_buffer->new_pages)) {
+			err = -ENOMEM;
+			goto out_err;
+		}
+
+		cpus_read_lock();
+
+		/* Can't run something on an offline CPU. */
+		if (!cpu_online(cpu_id))
+			rb_update_pages(cpu_buffer);
+		else {
+			schedule_work_on(cpu_id,
+					 &cpu_buffer->update_pages_work);
+			wait_for_completion(&cpu_buffer->update_done);
+		}
+
+		cpu_buffer->nr_pages_to_update = 0;
+		cpus_read_unlock();
+	}
+
+ out:
+	/*
+	 * The ring buffer resize can happen with the ring buffer
+	 * enabled, so that the update disturbs the tracing as little
+	 * as possible. But if the buffer is disabled, we do not need
+	 * to worry about that, and we can take the time to verify
+	 * that the buffer is not corrupt.
+	 */
+	if (atomic_read(&buffer->record_disabled)) {
+		atomic_inc(&buffer->record_disabled);
+		/*
+		 * Even though the buffer was disabled, we must make sure
+		 * that it is truly disabled before calling rb_check_pages.
+		 * There could have been a race between checking
+		 * record_disable and incrementing it.
+		 */
+		synchronize_rcu();
+		for_each_buffer_cpu(buffer, cpu) {
+			cpu_buffer = buffer->buffers[cpu];
+			rb_check_pages(cpu_buffer);
+		}
+		atomic_dec(&buffer->record_disabled);
+	}
+
+	atomic_dec(&buffer->resizing);
+	mutex_unlock(&buffer->mutex);
+	return 0;
+
+ out_err:
+	for_each_buffer_cpu(buffer, cpu) {
+		struct buffer_page *bpage, *tmp;
+
+		cpu_buffer = buffer->buffers[cpu];
+		cpu_buffer->nr_pages_to_update = 0;
+
+		if (list_empty(&cpu_buffer->new_pages))
+			continue;
+
+		list_for_each_entry_safe(bpage, tmp, &cpu_buffer->new_pages,
+					list) {
+			list_del_init(&bpage->list);
+			free_buffer_page(bpage);
+		}
+	}
+ out_err_unlock:
+	atomic_dec(&buffer->resizing);
+	mutex_unlock(&buffer->mutex);
+	return err;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_resize);
+
+void ring_buffer_change_overwrite(struct trace_buffer *buffer, int val)
+{
+	mutex_lock(&buffer->mutex);
+	if (val)
+		buffer->flags |= RB_FL_OVERWRITE;
+	else
+		buffer->flags &= ~RB_FL_OVERWRITE;
+	mutex_unlock(&buffer->mutex);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_change_overwrite);
+
+static __always_inline void *__rb_page_index(struct buffer_page *bpage, unsigned index)
+{
+	return bpage->page->data + index;
+}
+
+static __always_inline struct ring_buffer_event *
+rb_reader_event(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	return __rb_page_index(cpu_buffer->reader_page,
+			       cpu_buffer->reader_page->read);
+}
+
+static struct ring_buffer_event *
+rb_iter_head_event(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_event *event;
+	struct buffer_page *iter_head_page = iter->head_page;
+	unsigned long commit;
+	unsigned length;
+
+	if (iter->head != iter->next_event)
+		return iter->event;
+
+	/*
+	 * When the writer goes across pages, it issues a cmpxchg which
+	 * is a mb(), which will synchronize with the rmb here.
+	 * (see rb_tail_page_update() and __rb_reserve_next())
+	 */
+	commit = rb_page_commit(iter_head_page);
+	smp_rmb();
+
+	/* An event needs to be at least 8 bytes in size */
+	if (iter->head > commit - 8)
+		goto reset;
+
+	event = __rb_page_index(iter_head_page, iter->head);
+	length = rb_event_length(event);
+
+	/*
+	 * READ_ONCE() doesn't work on functions and we don't want the
+	 * compiler doing any crazy optimizations with length.
+	 */
+	barrier();
+
+	if ((iter->head + length) > commit || length > BUF_PAGE_SIZE)
+		/* Writer corrupted the read? */
+		goto reset;
+
+	memcpy(iter->event, event, length);
+	/*
+	 * If the page stamp is still the same after this rmb() then the
+	 * event was safely copied without the writer entering the page.
+	 */
+	smp_rmb();
+
+	/* Make sure the page didn't change since we read this */
+	if (iter->page_stamp != iter_head_page->page->time_stamp ||
+	    commit > rb_page_commit(iter_head_page))
+		goto reset;
+
+	iter->next_event = iter->head + length;
+	return iter->event;
+ reset:
+	/* Reset to the beginning */
+	iter->page_stamp = iter->read_stamp = iter->head_page->page->time_stamp;
+	iter->head = 0;
+	iter->next_event = 0;
+	iter->missed_events = 1;
+	return NULL;
+}
+
+/* Size is determined by what has been committed */
+static __always_inline unsigned rb_page_size(struct buffer_page *bpage)
+{
+	return rb_page_commit(bpage);
+}
+
+static __always_inline unsigned
+rb_commit_index(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	return rb_page_commit(cpu_buffer->commit_page);
+}
+
+static __always_inline unsigned
+rb_event_index(struct ring_buffer_event *event)
+{
+	unsigned long addr = (unsigned long)event;
+
+	return (addr & ~PAGE_MASK) - BUF_PAGE_HDR_SIZE;
+}
+
+static void rb_inc_iter(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+
+	/*
+	 * The iterator could be on the reader page (it starts there).
+	 * But the head could have moved, since the reader was
+	 * found. Check for this case and assign the iterator
+	 * to the head page instead of next.
+	 */
+	if (iter->head_page == cpu_buffer->reader_page)
+		iter->head_page = rb_set_head_page(cpu_buffer);
+	else
+		rb_inc_page(&iter->head_page);
+
+	iter->page_stamp = iter->read_stamp = iter->head_page->page->time_stamp;
+	iter->head = 0;
+	iter->next_event = 0;
+}
+
+/*
+ * rb_handle_head_page - writer hit the head page
+ *
+ * Returns: +1 to retry page
+ *           0 to continue
+ *          -1 on error
+ */
+static int
+rb_handle_head_page(struct ring_buffer_per_cpu *cpu_buffer,
+		    struct buffer_page *tail_page,
+		    struct buffer_page *next_page)
+{
+	struct buffer_page *new_head;
+	int entries;
+	int type;
+	int ret;
+
+	entries = rb_page_entries(next_page);
+
+	/*
+	 * The hard part is here. We need to move the head
+	 * forward, and protect against both readers on
+	 * other CPUs and writers coming in via interrupts.
+	 */
+	type = rb_head_page_set_update(cpu_buffer, next_page, tail_page,
+				       RB_PAGE_HEAD);
+
+	/*
+	 * type can be one of four:
+	 *  NORMAL - an interrupt already moved it for us
+	 *  HEAD   - we are the first to get here.
+	 *  UPDATE - we are the interrupt interrupting
+	 *           a current move.
+	 *  MOVED  - a reader on another CPU moved the next
+	 *           pointer to its reader page. Give up
+	 *           and try again.
+	 */
+
+	switch (type) {
+	case RB_PAGE_HEAD:
+		/*
+		 * We changed the head to UPDATE, thus
+		 * it is our responsibility to update
+		 * the counters.
+		 */
+		local_add(entries, &cpu_buffer->overrun);
+		local_sub(rb_page_commit(next_page), &cpu_buffer->entries_bytes);
+		local_inc(&cpu_buffer->pages_lost);
+
+		/*
+		 * The entries will be zeroed out when we move the
+		 * tail page.
+		 */
+
+		/* still more to do */
+		break;
+
+	case RB_PAGE_UPDATE:
+		/*
+		 * This is an interrupt that interrupt the
+		 * previous update. Still more to do.
+		 */
+		break;
+	case RB_PAGE_NORMAL:
+		/*
+		 * An interrupt came in before the update
+		 * and processed this for us.
+		 * Nothing left to do.
+		 */
+		return 1;
+	case RB_PAGE_MOVED:
+		/*
+		 * The reader is on another CPU and just did
+		 * a swap with our next_page.
+		 * Try again.
+		 */
+		return 1;
+	default:
+		RB_WARN_ON(cpu_buffer, 1); /* WTF??? */
+		return -1;
+	}
+
+	/*
+	 * Now that we are here, the old head pointer is
+	 * set to UPDATE. This will keep the reader from
+	 * swapping the head page with the reader page.
+	 * The reader (on another CPU) will spin till
+	 * we are finished.
+	 *
+	 * We just need to protect against interrupts
+	 * doing the job. We will set the next pointer
+	 * to HEAD. After that, we set the old pointer
+	 * to NORMAL, but only if it was HEAD before.
+	 * otherwise we are an interrupt, and only
+	 * want the outer most commit to reset it.
+	 */
+	new_head = next_page;
+	rb_inc_page(&new_head);
+
+	ret = rb_head_page_set_head(cpu_buffer, new_head, next_page,
+				    RB_PAGE_NORMAL);
+
+	/*
+	 * Valid returns are:
+	 *  HEAD   - an interrupt came in and already set it.
+	 *  NORMAL - One of two things:
+	 *            1) We really set it.
+	 *            2) A bunch of interrupts came in and moved
+	 *               the page forward again.
+	 */
+	switch (ret) {
+	case RB_PAGE_HEAD:
+	case RB_PAGE_NORMAL:
+		/* OK */
+		break;
+	default:
+		RB_WARN_ON(cpu_buffer, 1);
+		return -1;
+	}
+
+	/*
+	 * It is possible that an interrupt came in,
+	 * set the head up, then more interrupts came in
+	 * and moved it again. When we get back here,
+	 * the page would have been set to NORMAL but we
+	 * just set it back to HEAD.
+	 *
+	 * How do you detect this? Well, if that happened
+	 * the tail page would have moved.
+	 */
+	if (ret == RB_PAGE_NORMAL) {
+		struct buffer_page *buffer_tail_page;
+
+		buffer_tail_page = READ_ONCE(cpu_buffer->tail_page);
+		/*
+		 * If the tail had moved passed next, then we need
+		 * to reset the pointer.
+		 */
+		if (buffer_tail_page != tail_page &&
+		    buffer_tail_page != next_page)
+			rb_head_page_set_normal(cpu_buffer, new_head,
+						next_page,
+						RB_PAGE_HEAD);
+	}
+
+	/*
+	 * If this was the outer most commit (the one that
+	 * changed the original pointer from HEAD to UPDATE),
+	 * then it is up to us to reset it to NORMAL.
+	 */
+	if (type == RB_PAGE_HEAD) {
+		ret = rb_head_page_set_normal(cpu_buffer, next_page,
+					      tail_page,
+					      RB_PAGE_UPDATE);
+		if (RB_WARN_ON(cpu_buffer,
+			       ret != RB_PAGE_UPDATE))
+			return -1;
+	}
+
+	return 0;
+}
+
+static inline void
+rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer,
+	      unsigned long tail, struct rb_event_info *info)
+{
+	struct buffer_page *tail_page = info->tail_page;
+	struct ring_buffer_event *event;
+	unsigned long length = info->length;
+
+	/*
+	 * Only the event that crossed the page boundary
+	 * must fill the old tail_page with padding.
+	 */
+	if (tail >= BUF_PAGE_SIZE) {
+		/*
+		 * If the page was filled, then we still need
+		 * to update the real_end. Reset it to zero
+		 * and the reader will ignore it.
+		 */
+		if (tail == BUF_PAGE_SIZE)
+			tail_page->real_end = 0;
+
+		local_sub(length, &tail_page->write);
+		return;
+	}
+
+	event = __rb_page_index(tail_page, tail);
+
+	/*
+	 * Save the original length to the meta data.
+	 * This will be used by the reader to add lost event
+	 * counter.
+	 */
+	tail_page->real_end = tail;
+
+	/*
+	 * If this event is bigger than the minimum size, then
+	 * we need to be careful that we don't subtract the
+	 * write counter enough to allow another writer to slip
+	 * in on this page.
+	 * We put in a discarded commit instead, to make sure
+	 * that this space is not used again, and this space will
+	 * not be accounted into 'entries_bytes'.
+	 *
+	 * If we are less than the minimum size, we don't need to
+	 * worry about it.
+	 */
+	if (tail > (BUF_PAGE_SIZE - RB_EVNT_MIN_SIZE)) {
+		/* No room for any events */
+
+		/* Mark the rest of the page with padding */
+		rb_event_set_padding(event);
+
+		/* Make sure the padding is visible before the write update */
+		smp_wmb();
+
+		/* Set the write back to the previous setting */
+		local_sub(length, &tail_page->write);
+		return;
+	}
+
+	/* Put in a discarded event */
+	event->array[0] = (BUF_PAGE_SIZE - tail) - RB_EVNT_HDR_SIZE;
+	event->type_len = RINGBUF_TYPE_PADDING;
+	/* time delta must be non zero */
+	event->time_delta = 1;
+
+	/* account for padding bytes */
+	local_add(BUF_PAGE_SIZE - tail, &cpu_buffer->entries_bytes);
+
+	/* Make sure the padding is visible before the tail_page->write update */
+	smp_wmb();
+
+	/* Set write to end of buffer */
+	length = (tail + length) - BUF_PAGE_SIZE;
+	local_sub(length, &tail_page->write);
+}
+
+static inline void rb_end_commit(struct ring_buffer_per_cpu *cpu_buffer);
+
+/*
+ * This is the slow path, force gcc not to inline it.
+ */
+static noinline struct ring_buffer_event *
+rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
+	     unsigned long tail, struct rb_event_info *info)
+{
+	struct buffer_page *tail_page = info->tail_page;
+	struct buffer_page *commit_page = cpu_buffer->commit_page;
+	struct trace_buffer *buffer = cpu_buffer->buffer;
+	struct buffer_page *next_page;
+	int ret;
+
+	next_page = tail_page;
+
+	rb_inc_page(&next_page);
+
+	/*
+	 * If for some reason, we had an interrupt storm that made
+	 * it all the way around the buffer, bail, and warn
+	 * about it.
+	 */
+	if (unlikely(next_page == commit_page)) {
+		local_inc(&cpu_buffer->commit_overrun);
+		goto out_reset;
+	}
+
+	/*
+	 * This is where the fun begins!
+	 *
+	 * We are fighting against races between a reader that
+	 * could be on another CPU trying to swap its reader
+	 * page with the buffer head.
+	 *
+	 * We are also fighting against interrupts coming in and
+	 * moving the head or tail on us as well.
+	 *
+	 * If the next page is the head page then we have filled
+	 * the buffer, unless the commit page is still on the
+	 * reader page.
+	 */
+	if (rb_is_head_page(next_page, &tail_page->list)) {
+
+		/*
+		 * If the commit is not on the reader page, then
+		 * move the header page.
+		 */
+		if (!rb_is_reader_page(cpu_buffer->commit_page)) {
+			/*
+			 * If we are not in overwrite mode,
+			 * this is easy, just stop here.
+			 */
+			if (!(buffer->flags & RB_FL_OVERWRITE)) {
+				local_inc(&cpu_buffer->dropped_events);
+				goto out_reset;
+			}
+
+			ret = rb_handle_head_page(cpu_buffer,
+						  tail_page,
+						  next_page);
+			if (ret < 0)
+				goto out_reset;
+			if (ret)
+				goto out_again;
+		} else {
+			/*
+			 * We need to be careful here too. The
+			 * commit page could still be on the reader
+			 * page. We could have a small buffer, and
+			 * have filled up the buffer with events
+			 * from interrupts and such, and wrapped.
+			 *
+			 * Note, if the tail page is also on the
+			 * reader_page, we let it move out.
+			 */
+			if (unlikely((cpu_buffer->commit_page !=
+				      cpu_buffer->tail_page) &&
+				     (cpu_buffer->commit_page ==
+				      cpu_buffer->reader_page))) {
+				local_inc(&cpu_buffer->commit_overrun);
+				goto out_reset;
+			}
+		}
+	}
+
+	rb_tail_page_update(cpu_buffer, tail_page, next_page);
+
+ out_again:
+
+	rb_reset_tail(cpu_buffer, tail, info);
+
+	/* Commit what we have for now. */
+	rb_end_commit(cpu_buffer);
+	/* rb_end_commit() decs committing */
+	local_inc(&cpu_buffer->committing);
+
+	/* fail and let the caller try again */
+	return ERR_PTR(-EAGAIN);
+
+ out_reset:
+	/* reset write */
+	rb_reset_tail(cpu_buffer, tail, info);
+
+	return NULL;
+}
+
+/* Slow path */
+static struct ring_buffer_event *
+rb_add_time_stamp(struct ring_buffer_event *event, u64 delta, bool abs)
+{
+	if (abs)
+		event->type_len = RINGBUF_TYPE_TIME_STAMP;
+	else
+		event->type_len = RINGBUF_TYPE_TIME_EXTEND;
+
+	/* Not the first event on the page, or not delta? */
+	if (abs || rb_event_index(event)) {
+		event->time_delta = delta & TS_MASK;
+		event->array[0] = delta >> TS_SHIFT;
+	} else {
+		/* nope, just zero it */
+		event->time_delta = 0;
+		event->array[0] = 0;
+	}
+
+	return skip_time_extend(event);
+}
+
+#ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
+static inline bool sched_clock_stable(void)
+{
+	return true;
+}
+#endif
+
+static void
+rb_check_timestamp(struct ring_buffer_per_cpu *cpu_buffer,
+		   struct rb_event_info *info)
+{
+	u64 write_stamp;
+
+	WARN_ONCE(1, "Delta way too big! %llu ts=%llu before=%llu after=%llu write stamp=%llu\n%s",
+		  (unsigned long long)info->delta,
+		  (unsigned long long)info->ts,
+		  (unsigned long long)info->before,
+		  (unsigned long long)info->after,
+		  (unsigned long long)(rb_time_read(&cpu_buffer->write_stamp, &write_stamp) ? write_stamp : 0),
+		  sched_clock_stable() ? "" :
+		  "If you just came from a suspend/resume,\n"
+		  "please switch to the trace global clock:\n"
+		  "  echo global > /sys/kernel/debug/tracing/trace_clock\n"
+		  "or add trace_clock=global to the kernel command line\n");
+}
+
+static void rb_add_timestamp(struct ring_buffer_per_cpu *cpu_buffer,
+				      struct ring_buffer_event **event,
+				      struct rb_event_info *info,
+				      u64 *delta,
+				      unsigned int *length)
+{
+	bool abs = info->add_timestamp &
+		(RB_ADD_STAMP_FORCE | RB_ADD_STAMP_ABSOLUTE);
+
+	if (unlikely(info->delta > (1ULL << 59))) {
+		/*
+		 * Some timers can use more than 59 bits, and when a timestamp
+		 * is added to the buffer, it will lose those bits.
+		 */
+		if (abs && (info->ts & TS_MSB)) {
+			info->delta &= ABS_TS_MASK;
+
+		/* did the clock go backwards */
+		} else if (info->before == info->after && info->before > info->ts) {
+			/* not interrupted */
+			static int once;
+
+			/*
+			 * This is possible with a recalibrating of the TSC.
+			 * Do not produce a call stack, but just report it.
+			 */
+			if (!once) {
+				once++;
+				pr_warn("Ring buffer clock went backwards: %llu -> %llu\n",
+					info->before, info->ts);
+			}
+		} else
+			rb_check_timestamp(cpu_buffer, info);
+		if (!abs)
+			info->delta = 0;
+	}
+	*event = rb_add_time_stamp(*event, info->delta, abs);
+	*length -= RB_LEN_TIME_EXTEND;
+	*delta = 0;
+}
+
+/**
+ * rb_update_event - update event type and data
+ * @cpu_buffer: The per cpu buffer of the @event
+ * @event: the event to update
+ * @info: The info to update the @event with (contains length and delta)
+ *
+ * Update the type and data fields of the @event. The length
+ * is the actual size that is written to the ring buffer,
+ * and with this, we can determine what to place into the
+ * data field.
+ */
+static void
+rb_update_event(struct ring_buffer_per_cpu *cpu_buffer,
+		struct ring_buffer_event *event,
+		struct rb_event_info *info)
+{
+	unsigned length = info->length;
+	u64 delta = info->delta;
+	unsigned int nest = local_read(&cpu_buffer->committing) - 1;
+
+	if (!WARN_ON_ONCE(nest >= MAX_NEST))
+		cpu_buffer->event_stamp[nest] = info->ts;
+
+	/*
+	 * If we need to add a timestamp, then we
+	 * add it to the start of the reserved space.
+	 */
+	if (unlikely(info->add_timestamp))
+		rb_add_timestamp(cpu_buffer, &event, info, &delta, &length);
+
+	event->time_delta = delta;
+	length -= RB_EVNT_HDR_SIZE;
+	if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT) {
+		event->type_len = 0;
+		event->array[0] = length;
+	} else
+		event->type_len = DIV_ROUND_UP(length, RB_ALIGNMENT);
+}
+
+static unsigned rb_calculate_event_length(unsigned length)
+{
+	struct ring_buffer_event event; /* Used only for sizeof array */
+
+	/* zero length can cause confusions */
+	if (!length)
+		length++;
+
+	if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT)
+		length += sizeof(event.array[0]);
+
+	length += RB_EVNT_HDR_SIZE;
+	length = ALIGN(length, RB_ARCH_ALIGNMENT);
+
+	/*
+	 * In case the time delta is larger than the 27 bits for it
+	 * in the header, we need to add a timestamp. If another
+	 * event comes in when trying to discard this one to increase
+	 * the length, then the timestamp will be added in the allocated
+	 * space of this event. If length is bigger than the size needed
+	 * for the TIME_EXTEND, then padding has to be used. The events
+	 * length must be either RB_LEN_TIME_EXTEND, or greater than or equal
+	 * to RB_LEN_TIME_EXTEND + 8, as 8 is the minimum size for padding.
+	 * As length is a multiple of 4, we only need to worry if it
+	 * is 12 (RB_LEN_TIME_EXTEND + 4).
+	 */
+	if (length == RB_LEN_TIME_EXTEND + RB_ALIGNMENT)
+		length += RB_ALIGNMENT;
+
+	return length;
+}
+
+static inline int
+rb_try_to_discard(struct ring_buffer_per_cpu *cpu_buffer,
+		  struct ring_buffer_event *event)
+{
+	unsigned long new_index, old_index;
+	struct buffer_page *bpage;
+	unsigned long index;
+	unsigned long addr;
+
+	new_index = rb_event_index(event);
+	old_index = new_index + rb_event_ts_length(event);
+	addr = (unsigned long)event;
+	addr &= PAGE_MASK;
+
+	bpage = READ_ONCE(cpu_buffer->tail_page);
+
+	/*
+	 * Make sure the tail_page is still the same and
+	 * the next write location is the end of this event
+	 */
+	if (bpage->page == (void *)addr && rb_page_write(bpage) == old_index) {
+		unsigned long write_mask =
+			local_read(&bpage->write) & ~RB_WRITE_MASK;
+		unsigned long event_length = rb_event_length(event);
+
+		/*
+		 * For the before_stamp to be different than the write_stamp
+		 * to make sure that the next event adds an absolute
+		 * value and does not rely on the saved write stamp, which
+		 * is now going to be bogus.
+		 *
+		 * By setting the before_stamp to zero, the next event
+		 * is not going to use the write_stamp and will instead
+		 * create an absolute timestamp. This means there's no
+		 * reason to update the wirte_stamp!
+		 */
+		rb_time_set(&cpu_buffer->before_stamp, 0);
+
+		/*
+		 * If an event were to come in now, it would see that the
+		 * write_stamp and the before_stamp are different, and assume
+		 * that this event just added itself before updating
+		 * the write stamp. The interrupting event will fix the
+		 * write stamp for us, and use an absolute timestamp.
+		 */
+
+		/*
+		 * This is on the tail page. It is possible that
+		 * a write could come in and move the tail page
+		 * and write to the next page. That is fine
+		 * because we just shorten what is on this page.
+		 */
+		old_index += write_mask;
+		new_index += write_mask;
+		index = local_cmpxchg(&bpage->write, old_index, new_index);
+		if (index == old_index) {
+			/* update counters */
+			local_sub(event_length, &cpu_buffer->entries_bytes);
+			return 1;
+		}
+	}
+
+	/* could not discard */
+	return 0;
+}
+
+static void rb_start_commit(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	local_inc(&cpu_buffer->committing);
+	local_inc(&cpu_buffer->commits);
+}
+
+static __always_inline void
+rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	unsigned long max_count;
+
+	/*
+	 * We only race with interrupts and NMIs on this CPU.
+	 * If we own the commit event, then we can commit
+	 * all others that interrupted us, since the interruptions
+	 * are in stack format (they finish before they come
+	 * back to us). This allows us to do a simple loop to
+	 * assign the commit to the tail.
+	 */
+ again:
+	max_count = cpu_buffer->nr_pages * 100;
+
+	while (cpu_buffer->commit_page != READ_ONCE(cpu_buffer->tail_page)) {
+		if (RB_WARN_ON(cpu_buffer, !(--max_count)))
+			return;
+		if (RB_WARN_ON(cpu_buffer,
+			       rb_is_reader_page(cpu_buffer->tail_page)))
+			return;
+		/*
+		 * No need for a memory barrier here, as the update
+		 * of the tail_page did it for this page.
+		 */
+		local_set(&cpu_buffer->commit_page->page->commit,
+			  rb_page_write(cpu_buffer->commit_page));
+		rb_inc_page(&cpu_buffer->commit_page);
+		/* add barrier to keep gcc from optimizing too much */
+		barrier();
+	}
+	while (rb_commit_index(cpu_buffer) !=
+	       rb_page_write(cpu_buffer->commit_page)) {
+
+		/* Make sure the readers see the content of what is committed. */
+		smp_wmb();
+		local_set(&cpu_buffer->commit_page->page->commit,
+			  rb_page_write(cpu_buffer->commit_page));
+		RB_WARN_ON(cpu_buffer,
+			   local_read(&cpu_buffer->commit_page->page->commit) &
+			   ~RB_WRITE_MASK);
+		barrier();
+	}
+
+	/* again, keep gcc from optimizing */
+	barrier();
+
+	/*
+	 * If an interrupt came in just after the first while loop
+	 * and pushed the tail page forward, we will be left with
+	 * a dangling commit that will never go forward.
+	 */
+	if (unlikely(cpu_buffer->commit_page != READ_ONCE(cpu_buffer->tail_page)))
+		goto again;
+}
+
+static __always_inline void rb_end_commit(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	unsigned long commits;
+
+	if (RB_WARN_ON(cpu_buffer,
+		       !local_read(&cpu_buffer->committing)))
+		return;
+
+ again:
+	commits = local_read(&cpu_buffer->commits);
+	/* synchronize with interrupts */
+	barrier();
+	if (local_read(&cpu_buffer->committing) == 1)
+		rb_set_commit_to_write(cpu_buffer);
+
+	local_dec(&cpu_buffer->committing);
+
+	/* synchronize with interrupts */
+	barrier();
+
+	/*
+	 * Need to account for interrupts coming in between the
+	 * updating of the commit page and the clearing of the
+	 * committing counter.
+	 */
+	if (unlikely(local_read(&cpu_buffer->commits) != commits) &&
+	    !local_read(&cpu_buffer->committing)) {
+		local_inc(&cpu_buffer->committing);
+		goto again;
+	}
+}
+
+static inline void rb_event_discard(struct ring_buffer_event *event)
+{
+	if (extended_time(event))
+		event = skip_time_extend(event);
+
+	/* array[0] holds the actual length for the discarded event */
+	event->array[0] = rb_event_data_length(event) - RB_EVNT_HDR_SIZE;
+	event->type_len = RINGBUF_TYPE_PADDING;
+	/* time delta must be non zero */
+	if (!event->time_delta)
+		event->time_delta = 1;
+}
+
+static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer,
+		      struct ring_buffer_event *event)
+{
+	local_inc(&cpu_buffer->entries);
+	rb_end_commit(cpu_buffer);
+}
+
+static __always_inline void
+rb_wakeups(struct trace_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
+{
+	if (buffer->irq_work.waiters_pending) {
+		buffer->irq_work.waiters_pending = false;
+		/* irq_work_queue() supplies it's own memory barriers */
+		irq_work_queue(&buffer->irq_work.work);
+	}
+
+	if (cpu_buffer->irq_work.waiters_pending) {
+		cpu_buffer->irq_work.waiters_pending = false;
+		/* irq_work_queue() supplies it's own memory barriers */
+		irq_work_queue(&cpu_buffer->irq_work.work);
+	}
+
+	if (cpu_buffer->last_pages_touch == local_read(&cpu_buffer->pages_touched))
+		return;
+
+	if (cpu_buffer->reader_page == cpu_buffer->commit_page)
+		return;
+
+	if (!cpu_buffer->irq_work.full_waiters_pending)
+		return;
+
+	cpu_buffer->last_pages_touch = local_read(&cpu_buffer->pages_touched);
+
+	if (!full_hit(buffer, cpu_buffer->cpu, cpu_buffer->shortest_full))
+		return;
+
+	cpu_buffer->irq_work.wakeup_full = true;
+	cpu_buffer->irq_work.full_waiters_pending = false;
+	/* irq_work_queue() supplies it's own memory barriers */
+	irq_work_queue(&cpu_buffer->irq_work.work);
+}
+
+#ifdef CONFIG_RING_BUFFER_RECORD_RECURSION
+# define do_ring_buffer_record_recursion()	\
+	do_ftrace_record_recursion(_THIS_IP_, _RET_IP_)
+#else
+# define do_ring_buffer_record_recursion() do { } while (0)
+#endif
+
+/*
+ * The lock and unlock are done within a preempt disable section.
+ * The current_context per_cpu variable can only be modified
+ * by the current task between lock and unlock. But it can
+ * be modified more than once via an interrupt. To pass this
+ * information from the lock to the unlock without having to
+ * access the 'in_interrupt()' functions again (which do show
+ * a bit of overhead in something as critical as function tracing,
+ * we use a bitmask trick.
+ *
+ *  bit 1 =  NMI context
+ *  bit 2 =  IRQ context
+ *  bit 3 =  SoftIRQ context
+ *  bit 4 =  normal context.
+ *
+ * This works because this is the order of contexts that can
+ * preempt other contexts. A SoftIRQ never preempts an IRQ
+ * context.
+ *
+ * When the context is determined, the corresponding bit is
+ * checked and set (if it was set, then a recursion of that context
+ * happened).
+ *
+ * On unlock, we need to clear this bit. To do so, just subtract
+ * 1 from the current_context and AND it to itself.
+ *
+ * (binary)
+ *  101 - 1 = 100
+ *  101 & 100 = 100 (clearing bit zero)
+ *
+ *  1010 - 1 = 1001
+ *  1010 & 1001 = 1000 (clearing bit 1)
+ *
+ * The least significant bit can be cleared this way, and it
+ * just so happens that it is the same bit corresponding to
+ * the current context.
+ *
+ * Now the TRANSITION bit breaks the above slightly. The TRANSITION bit
+ * is set when a recursion is detected at the current context, and if
+ * the TRANSITION bit is already set, it will fail the recursion.
+ * This is needed because there's a lag between the changing of
+ * interrupt context and updating the preempt count. In this case,
+ * a false positive will be found. To handle this, one extra recursion
+ * is allowed, and this is done by the TRANSITION bit. If the TRANSITION
+ * bit is already set, then it is considered a recursion and the function
+ * ends. Otherwise, the TRANSITION bit is set, and that bit is returned.
+ *
+ * On the trace_recursive_unlock(), the TRANSITION bit will be the first
+ * to be cleared. Even if it wasn't the context that set it. That is,
+ * if an interrupt comes in while NORMAL bit is set and the ring buffer
+ * is called before preempt_count() is updated, since the check will
+ * be on the NORMAL bit, the TRANSITION bit will then be set. If an
+ * NMI then comes in, it will set the NMI bit, but when the NMI code
+ * does the trace_recursive_unlock() it will clear the TRANSITION bit
+ * and leave the NMI bit set. But this is fine, because the interrupt
+ * code that set the TRANSITION bit will then clear the NMI bit when it
+ * calls trace_recursive_unlock(). If another NMI comes in, it will
+ * set the TRANSITION bit and continue.
+ *
+ * Note: The TRANSITION bit only handles a single transition between context.
+ */
+
+static __always_inline int
+trace_recursive_lock(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	unsigned int val = cpu_buffer->current_context;
+	int bit = interrupt_context_level();
+
+	bit = RB_CTX_NORMAL - bit;
+
+	if (unlikely(val & (1 << (bit + cpu_buffer->nest)))) {
+		/*
+		 * It is possible that this was called by transitioning
+		 * between interrupt context, and preempt_count() has not
+		 * been updated yet. In this case, use the TRANSITION bit.
+		 */
+		bit = RB_CTX_TRANSITION;
+		if (val & (1 << (bit + cpu_buffer->nest))) {
+			do_ring_buffer_record_recursion();
+			return 1;
+		}
+	}
+
+	val |= (1 << (bit + cpu_buffer->nest));
+	cpu_buffer->current_context = val;
+
+	return 0;
+}
+
+static __always_inline void
+trace_recursive_unlock(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	cpu_buffer->current_context &=
+		cpu_buffer->current_context - (1 << cpu_buffer->nest);
+}
+
+/* The recursive locking above uses 5 bits */
+#define NESTED_BITS 5
+
+/**
+ * ring_buffer_nest_start - Allow to trace while nested
+ * @buffer: The ring buffer to modify
+ *
+ * The ring buffer has a safety mechanism to prevent recursion.
+ * But there may be a case where a trace needs to be done while
+ * tracing something else. In this case, calling this function
+ * will allow this function to nest within a currently active
+ * ring_buffer_lock_reserve().
+ *
+ * Call this function before calling another ring_buffer_lock_reserve() and
+ * call ring_buffer_nest_end() after the nested ring_buffer_unlock_commit().
+ */
+void ring_buffer_nest_start(struct trace_buffer *buffer)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	int cpu;
+
+	/* Enabled by ring_buffer_nest_end() */
+	preempt_disable_notrace();
+	cpu = raw_smp_processor_id();
+	cpu_buffer = buffer->buffers[cpu];
+	/* This is the shift value for the above recursive locking */
+	cpu_buffer->nest += NESTED_BITS;
+}
+
+/**
+ * ring_buffer_nest_end - Allow to trace while nested
+ * @buffer: The ring buffer to modify
+ *
+ * Must be called after ring_buffer_nest_start() and after the
+ * ring_buffer_unlock_commit().
+ */
+void ring_buffer_nest_end(struct trace_buffer *buffer)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	int cpu;
+
+	/* disabled by ring_buffer_nest_start() */
+	cpu = raw_smp_processor_id();
+	cpu_buffer = buffer->buffers[cpu];
+	/* This is the shift value for the above recursive locking */
+	cpu_buffer->nest -= NESTED_BITS;
+	preempt_enable_notrace();
+}
+
+/**
+ * ring_buffer_unlock_commit - commit a reserved
+ * @buffer: The buffer to commit to
+ * @event: The event pointer to commit.
+ *
+ * This commits the data to the ring buffer, and releases any locks held.
+ *
+ * Must be paired with ring_buffer_lock_reserve.
+ */
+int ring_buffer_unlock_commit(struct trace_buffer *buffer,
+			      struct ring_buffer_event *event)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	int cpu = raw_smp_processor_id();
+
+	cpu_buffer = buffer->buffers[cpu];
+
+	rb_commit(cpu_buffer, event);
+
+	rb_wakeups(buffer, cpu_buffer);
+
+	trace_recursive_unlock(cpu_buffer);
+
+	preempt_enable_notrace();
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_unlock_commit);
+
+/* Special value to validate all deltas on a page. */
+#define CHECK_FULL_PAGE		1L
+
+#ifdef CONFIG_RING_BUFFER_VALIDATE_TIME_DELTAS
+static void dump_buffer_page(struct buffer_data_page *bpage,
+			     struct rb_event_info *info,
+			     unsigned long tail)
+{
+	struct ring_buffer_event *event;
+	u64 ts, delta;
+	int e;
+
+	ts = bpage->time_stamp;
+	pr_warn("  [%lld] PAGE TIME STAMP\n", ts);
+
+	for (e = 0; e < tail; e += rb_event_length(event)) {
+
+		event = (struct ring_buffer_event *)(bpage->data + e);
+
+		switch (event->type_len) {
+
+		case RINGBUF_TYPE_TIME_EXTEND:
+			delta = rb_event_time_stamp(event);
+			ts += delta;
+			pr_warn("  [%lld] delta:%lld TIME EXTEND\n", ts, delta);
+			break;
+
+		case RINGBUF_TYPE_TIME_STAMP:
+			delta = rb_event_time_stamp(event);
+			ts = rb_fix_abs_ts(delta, ts);
+			pr_warn("  [%lld] absolute:%lld TIME STAMP\n", ts, delta);
+			break;
+
+		case RINGBUF_TYPE_PADDING:
+			ts += event->time_delta;
+			pr_warn("  [%lld] delta:%d PADDING\n", ts, event->time_delta);
+			break;
+
+		case RINGBUF_TYPE_DATA:
+			ts += event->time_delta;
+			pr_warn("  [%lld] delta:%d\n", ts, event->time_delta);
+			break;
+
+		default:
+			break;
+		}
+	}
+}
+
+static DEFINE_PER_CPU(atomic_t, checking);
+static atomic_t ts_dump;
+
+/*
+ * Check if the current event time stamp matches the deltas on
+ * the buffer page.
+ */
+static void check_buffer(struct ring_buffer_per_cpu *cpu_buffer,
+			 struct rb_event_info *info,
+			 unsigned long tail)
+{
+	struct ring_buffer_event *event;
+	struct buffer_data_page *bpage;
+	u64 ts, delta;
+	bool full = false;
+	int e;
+
+	bpage = info->tail_page->page;
+
+	if (tail == CHECK_FULL_PAGE) {
+		full = true;
+		tail = local_read(&bpage->commit);
+	} else if (info->add_timestamp &
+		   (RB_ADD_STAMP_FORCE | RB_ADD_STAMP_ABSOLUTE)) {
+		/* Ignore events with absolute time stamps */
+		return;
+	}
+
+	/*
+	 * Do not check the first event (skip possible extends too).
+	 * Also do not check if previous events have not been committed.
+	 */
+	if (tail <= 8 || tail > local_read(&bpage->commit))
+		return;
+
+	/*
+	 * If this interrupted another event,
+	 */
+	if (atomic_inc_return(this_cpu_ptr(&checking)) != 1)
+		goto out;
+
+	ts = bpage->time_stamp;
+
+	for (e = 0; e < tail; e += rb_event_length(event)) {
+
+		event = (struct ring_buffer_event *)(bpage->data + e);
+
+		switch (event->type_len) {
+
+		case RINGBUF_TYPE_TIME_EXTEND:
+			delta = rb_event_time_stamp(event);
+			ts += delta;
+			break;
+
+		case RINGBUF_TYPE_TIME_STAMP:
+			delta = rb_event_time_stamp(event);
+			ts = rb_fix_abs_ts(delta, ts);
+			break;
+
+		case RINGBUF_TYPE_PADDING:
+			if (event->time_delta == 1)
+				break;
+			fallthrough;
+		case RINGBUF_TYPE_DATA:
+			ts += event->time_delta;
+			break;
+
+		default:
+			RB_WARN_ON(cpu_buffer, 1);
+		}
+	}
+	if ((full && ts > info->ts) ||
+	    (!full && ts + info->delta != info->ts)) {
+		/* If another report is happening, ignore this one */
+		if (atomic_inc_return(&ts_dump) != 1) {
+			atomic_dec(&ts_dump);
+			goto out;
+		}
+		atomic_inc(&cpu_buffer->record_disabled);
+		/* There's some cases in boot up that this can happen */
+		WARN_ON_ONCE(system_state != SYSTEM_BOOTING);
+		pr_warn("[CPU: %d]TIME DOES NOT MATCH expected:%lld actual:%lld delta:%lld before:%lld after:%lld%s\n",
+			cpu_buffer->cpu,
+			ts + info->delta, info->ts, info->delta,
+			info->before, info->after,
+			full ? " (full)" : "");
+		dump_buffer_page(bpage, info, tail);
+		atomic_dec(&ts_dump);
+		/* Do not re-enable checking */
+		return;
+	}
+out:
+	atomic_dec(this_cpu_ptr(&checking));
+}
+#else
+static inline void check_buffer(struct ring_buffer_per_cpu *cpu_buffer,
+			 struct rb_event_info *info,
+			 unsigned long tail)
+{
+}
+#endif /* CONFIG_RING_BUFFER_VALIDATE_TIME_DELTAS */
+
+static struct ring_buffer_event *
+__rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
+		  struct rb_event_info *info)
+{
+	struct ring_buffer_event *event;
+	struct buffer_page *tail_page;
+	unsigned long tail, write, w;
+	bool a_ok;
+	bool b_ok;
+
+	/* Don't let the compiler play games with cpu_buffer->tail_page */
+	tail_page = info->tail_page = READ_ONCE(cpu_buffer->tail_page);
+
+ /*A*/	w = local_read(&tail_page->write) & RB_WRITE_MASK;
+	barrier();
+	b_ok = rb_time_read(&cpu_buffer->before_stamp, &info->before);
+	a_ok = rb_time_read(&cpu_buffer->write_stamp, &info->after);
+	barrier();
+	info->ts = rb_time_stamp(cpu_buffer->buffer);
+
+	if ((info->add_timestamp & RB_ADD_STAMP_ABSOLUTE)) {
+		info->delta = info->ts;
+	} else {
+		/*
+		 * If interrupting an event time update, we may need an
+		 * absolute timestamp.
+		 * Don't bother if this is the start of a new page (w == 0).
+		 */
+		if (!w) {
+			/* Use the sub-buffer timestamp */
+			info->delta = 0;
+		} else if (unlikely(!a_ok || !b_ok || info->before != info->after)) {
+			info->add_timestamp |= RB_ADD_STAMP_FORCE | RB_ADD_STAMP_EXTEND;
+			info->length += RB_LEN_TIME_EXTEND;
+		} else {
+			info->delta = info->ts - info->after;
+			if (unlikely(test_time_stamp(info->delta))) {
+				info->add_timestamp |= RB_ADD_STAMP_EXTEND;
+				info->length += RB_LEN_TIME_EXTEND;
+			}
+		}
+	}
+
+ /*B*/	rb_time_set(&cpu_buffer->before_stamp, info->ts);
+
+ /*C*/	write = local_add_return(info->length, &tail_page->write);
+
+	/* set write to only the index of the write */
+	write &= RB_WRITE_MASK;
+
+	tail = write - info->length;
+
+	/* See if we shot pass the end of this buffer page */
+	if (unlikely(write > BUF_PAGE_SIZE)) {
+		check_buffer(cpu_buffer, info, CHECK_FULL_PAGE);
+		return rb_move_tail(cpu_buffer, tail, info);
+	}
+
+	if (likely(tail == w)) {
+		/* Nothing interrupted us between A and C */
+ /*D*/		rb_time_set(&cpu_buffer->write_stamp, info->ts);
+		/*
+		 * If something came in between C and D, the write stamp
+		 * may now not be in sync. But that's fine as the before_stamp
+		 * will be different and then next event will just be forced
+		 * to use an absolute timestamp.
+		 */
+		if (likely(!(info->add_timestamp &
+			     (RB_ADD_STAMP_FORCE | RB_ADD_STAMP_ABSOLUTE))))
+			/* This did not interrupt any time update */
+			info->delta = info->ts - info->after;
+		else
+			/* Just use full timestamp for interrupting event */
+			info->delta = info->ts;
+		check_buffer(cpu_buffer, info, tail);
+	} else {
+		u64 ts;
+		/* SLOW PATH - Interrupted between A and C */
+
+		/* Save the old before_stamp */
+		a_ok = rb_time_read(&cpu_buffer->before_stamp, &info->before);
+		RB_WARN_ON(cpu_buffer, !a_ok);
+
+		/*
+		 * Read a new timestamp and update the before_stamp to make
+		 * the next event after this one force using an absolute
+		 * timestamp. This is in case an interrupt were to come in
+		 * between E and F.
+		 */
+		ts = rb_time_stamp(cpu_buffer->buffer);
+		rb_time_set(&cpu_buffer->before_stamp, ts);
+
+		barrier();
+ /*E*/		a_ok = rb_time_read(&cpu_buffer->write_stamp, &info->after);
+		/* Was interrupted before here, write_stamp must be valid */
+		RB_WARN_ON(cpu_buffer, !a_ok);
+		barrier();
+ /*F*/		if (write == (local_read(&tail_page->write) & RB_WRITE_MASK) &&
+		    info->after == info->before && info->after < ts) {
+			/*
+			 * Nothing came after this event between C and F, it is
+			 * safe to use info->after for the delta as it
+			 * matched info->before and is still valid.
+			 */
+			info->delta = ts - info->after;
+		} else {
+			/*
+			 * Interrupted between C and F:
+			 * Lost the previous events time stamp. Just set the
+			 * delta to zero, and this will be the same time as
+			 * the event this event interrupted. And the events that
+			 * came after this will still be correct (as they would
+			 * have built their delta on the previous event.
+			 */
+			info->delta = 0;
+		}
+		info->ts = ts;
+		info->add_timestamp &= ~RB_ADD_STAMP_FORCE;
+	}
+
+	/*
+	 * If this is the first commit on the page, then it has the same
+	 * timestamp as the page itself.
+	 */
+	if (unlikely(!tail && !(info->add_timestamp &
+				(RB_ADD_STAMP_FORCE | RB_ADD_STAMP_ABSOLUTE))))
+		info->delta = 0;
+
+	/* We reserved something on the buffer */
+
+	event = __rb_page_index(tail_page, tail);
+	rb_update_event(cpu_buffer, event, info);
+
+	local_inc(&tail_page->entries);
+
+	/*
+	 * If this is the first commit on the page, then update
+	 * its timestamp.
+	 */
+	if (unlikely(!tail))
+		tail_page->page->time_stamp = info->ts;
+
+	/* account for these added bytes */
+	local_add(info->length, &cpu_buffer->entries_bytes);
+
+	return event;
+}
+
+static __always_inline struct ring_buffer_event *
+rb_reserve_next_event(struct trace_buffer *buffer,
+		      struct ring_buffer_per_cpu *cpu_buffer,
+		      unsigned long length)
+{
+	struct ring_buffer_event *event;
+	struct rb_event_info info;
+	int nr_loops = 0;
+	int add_ts_default;
+
+	/* ring buffer does cmpxchg, make sure it is safe in NMI context */
+	if (!IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG) &&
+	    (unlikely(in_nmi()))) {
+		return NULL;
+	}
+
+	rb_start_commit(cpu_buffer);
+	/* The commit page can not change after this */
+
+#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
+	/*
+	 * Due to the ability to swap a cpu buffer from a buffer
+	 * it is possible it was swapped before we committed.
+	 * (committing stops a swap). We check for it here and
+	 * if it happened, we have to fail the write.
+	 */
+	barrier();
+	if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {
+		local_dec(&cpu_buffer->committing);
+		local_dec(&cpu_buffer->commits);
+		return NULL;
+	}
+#endif
+
+	info.length = rb_calculate_event_length(length);
+
+	if (ring_buffer_time_stamp_abs(cpu_buffer->buffer)) {
+		add_ts_default = RB_ADD_STAMP_ABSOLUTE;
+		info.length += RB_LEN_TIME_EXTEND;
+		if (info.length > BUF_MAX_DATA_SIZE)
+			goto out_fail;
+	} else {
+		add_ts_default = RB_ADD_STAMP_NONE;
+	}
+
+ again:
+	info.add_timestamp = add_ts_default;
+	info.delta = 0;
+
+	/*
+	 * We allow for interrupts to reenter here and do a trace.
+	 * If one does, it will cause this original code to loop
+	 * back here. Even with heavy interrupts happening, this
+	 * should only happen a few times in a row. If this happens
+	 * 1000 times in a row, there must be either an interrupt
+	 * storm or we have something buggy.
+	 * Bail!
+	 */
+	if (RB_WARN_ON(cpu_buffer, ++nr_loops > 1000))
+		goto out_fail;
+
+	event = __rb_reserve_next(cpu_buffer, &info);
+
+	if (unlikely(PTR_ERR(event) == -EAGAIN)) {
+		if (info.add_timestamp & (RB_ADD_STAMP_FORCE | RB_ADD_STAMP_EXTEND))
+			info.length -= RB_LEN_TIME_EXTEND;
+		goto again;
+	}
+
+	if (likely(event))
+		return event;
+ out_fail:
+	rb_end_commit(cpu_buffer);
+	return NULL;
+}
+
+/**
+ * ring_buffer_lock_reserve - reserve a part of the buffer
+ * @buffer: the ring buffer to reserve from
+ * @length: the length of the data to reserve (excluding event header)
+ *
+ * Returns a reserved event on the ring buffer to copy directly to.
+ * The user of this interface will need to get the body to write into
+ * and can use the ring_buffer_event_data() interface.
+ *
+ * The length is the length of the data needed, not the event length
+ * which also includes the event header.
+ *
+ * Must be paired with ring_buffer_unlock_commit, unless NULL is returned.
+ * If NULL is returned, then nothing has been allocated or locked.
+ */
+struct ring_buffer_event *
+ring_buffer_lock_reserve(struct trace_buffer *buffer, unsigned long length)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct ring_buffer_event *event;
+	int cpu;
+
+	/* If we are tracing schedule, we don't want to recurse */
+	preempt_disable_notrace();
+
+	if (unlikely(atomic_read(&buffer->record_disabled)))
+		goto out;
+
+	cpu = raw_smp_processor_id();
+
+	if (unlikely(!cpumask_test_cpu(cpu, buffer->cpumask)))
+		goto out;
+
+	cpu_buffer = buffer->buffers[cpu];
+
+	if (unlikely(atomic_read(&cpu_buffer->record_disabled)))
+		goto out;
+
+	if (unlikely(length > BUF_MAX_DATA_SIZE))
+		goto out;
+
+	if (unlikely(trace_recursive_lock(cpu_buffer)))
+		goto out;
+
+	event = rb_reserve_next_event(buffer, cpu_buffer, length);
+	if (!event)
+		goto out_unlock;
+
+	return event;
+
+ out_unlock:
+	trace_recursive_unlock(cpu_buffer);
+ out:
+	preempt_enable_notrace();
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_lock_reserve);
+
+/*
+ * Decrement the entries to the page that an event is on.
+ * The event does not even need to exist, only the pointer
+ * to the page it is on. This may only be called before the commit
+ * takes place.
+ */
+static inline void
+rb_decrement_entry(struct ring_buffer_per_cpu *cpu_buffer,
+		   struct ring_buffer_event *event)
+{
+	unsigned long addr = (unsigned long)event;
+	struct buffer_page *bpage = cpu_buffer->commit_page;
+	struct buffer_page *start;
+
+	addr &= PAGE_MASK;
+
+	/* Do the likely case first */
+	if (likely(bpage->page == (void *)addr)) {
+		local_dec(&bpage->entries);
+		return;
+	}
+
+	/*
+	 * Because the commit page may be on the reader page we
+	 * start with the next page and check the end loop there.
+	 */
+	rb_inc_page(&bpage);
+	start = bpage;
+	do {
+		if (bpage->page == (void *)addr) {
+			local_dec(&bpage->entries);
+			return;
+		}
+		rb_inc_page(&bpage);
+	} while (bpage != start);
+
+	/* commit not part of this buffer?? */
+	RB_WARN_ON(cpu_buffer, 1);
+}
+
+/**
+ * ring_buffer_discard_commit - discard an event that has not been committed
+ * @buffer: the ring buffer
+ * @event: non committed event to discard
+ *
+ * Sometimes an event that is in the ring buffer needs to be ignored.
+ * This function lets the user discard an event in the ring buffer
+ * and then that event will not be read later.
+ *
+ * This function only works if it is called before the item has been
+ * committed. It will try to free the event from the ring buffer
+ * if another event has not been added behind it.
+ *
+ * If another event has been added behind it, it will set the event
+ * up as discarded, and perform the commit.
+ *
+ * If this function is called, do not call ring_buffer_unlock_commit on
+ * the event.
+ */
+void ring_buffer_discard_commit(struct trace_buffer *buffer,
+				struct ring_buffer_event *event)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	int cpu;
+
+	/* The event is discarded regardless */
+	rb_event_discard(event);
+
+	cpu = smp_processor_id();
+	cpu_buffer = buffer->buffers[cpu];
+
+	/*
+	 * This must only be called if the event has not been
+	 * committed yet. Thus we can assume that preemption
+	 * is still disabled.
+	 */
+	RB_WARN_ON(buffer, !local_read(&cpu_buffer->committing));
+
+	rb_decrement_entry(cpu_buffer, event);
+	if (rb_try_to_discard(cpu_buffer, event))
+		goto out;
+
+ out:
+	rb_end_commit(cpu_buffer);
+
+	trace_recursive_unlock(cpu_buffer);
+
+	preempt_enable_notrace();
+
+}
+EXPORT_SYMBOL_GPL(ring_buffer_discard_commit);
+
+/**
+ * ring_buffer_write - write data to the buffer without reserving
+ * @buffer: The ring buffer to write to.
+ * @length: The length of the data being written (excluding the event header)
+ * @data: The data to write to the buffer.
+ *
+ * This is like ring_buffer_lock_reserve and ring_buffer_unlock_commit as
+ * one function. If you already have the data to write to the buffer, it
+ * may be easier to simply call this function.
+ *
+ * Note, like ring_buffer_lock_reserve, the length is the length of the data
+ * and not the length of the event which would hold the header.
+ */
+int ring_buffer_write(struct trace_buffer *buffer,
+		      unsigned long length,
+		      void *data)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct ring_buffer_event *event;
+	void *body;
+	int ret = -EBUSY;
+	int cpu;
+
+	preempt_disable_notrace();
+
+	if (atomic_read(&buffer->record_disabled))
+		goto out;
+
+	cpu = raw_smp_processor_id();
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		goto out;
+
+	cpu_buffer = buffer->buffers[cpu];
+
+	if (atomic_read(&cpu_buffer->record_disabled))
+		goto out;
+
+	if (length > BUF_MAX_DATA_SIZE)
+		goto out;
+
+	if (unlikely(trace_recursive_lock(cpu_buffer)))
+		goto out;
+
+	event = rb_reserve_next_event(buffer, cpu_buffer, length);
+	if (!event)
+		goto out_unlock;
+
+	body = rb_event_data(event);
+
+	memcpy(body, data, length);
+
+	rb_commit(cpu_buffer, event);
+
+	rb_wakeups(buffer, cpu_buffer);
+
+	ret = 0;
+
+ out_unlock:
+	trace_recursive_unlock(cpu_buffer);
+
+ out:
+	preempt_enable_notrace();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_write);
+
+static bool rb_per_cpu_empty(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct buffer_page *reader = cpu_buffer->reader_page;
+	struct buffer_page *head = rb_set_head_page(cpu_buffer);
+	struct buffer_page *commit = cpu_buffer->commit_page;
+
+	/* In case of error, head will be NULL */
+	if (unlikely(!head))
+		return true;
+
+	/* Reader should exhaust content in reader page */
+	if (reader->read != rb_page_commit(reader))
+		return false;
+
+	/*
+	 * If writers are committing on the reader page, knowing all
+	 * committed content has been read, the ring buffer is empty.
+	 */
+	if (commit == reader)
+		return true;
+
+	/*
+	 * If writers are committing on a page other than reader page
+	 * and head page, there should always be content to read.
+	 */
+	if (commit != head)
+		return false;
+
+	/*
+	 * Writers are committing on the head page, we just need
+	 * to care about there're committed data, and the reader will
+	 * swap reader page with head page when it is to read data.
+	 */
+	return rb_page_commit(commit) == 0;
+}
+
+/**
+ * ring_buffer_record_disable - stop all writes into the buffer
+ * @buffer: The ring buffer to stop writes to.
+ *
+ * This prevents all writes to the buffer. Any attempt to write
+ * to the buffer after this will fail and return NULL.
+ *
+ * The caller should call synchronize_rcu() after this.
+ */
+void ring_buffer_record_disable(struct trace_buffer *buffer)
+{
+	atomic_inc(&buffer->record_disabled);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_record_disable);
+
+/**
+ * ring_buffer_record_enable - enable writes to the buffer
+ * @buffer: The ring buffer to enable writes
+ *
+ * Note, multiple disables will need the same number of enables
+ * to truly enable the writing (much like preempt_disable).
+ */
+void ring_buffer_record_enable(struct trace_buffer *buffer)
+{
+	atomic_dec(&buffer->record_disabled);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_record_enable);
+
+/**
+ * ring_buffer_record_off - stop all writes into the buffer
+ * @buffer: The ring buffer to stop writes to.
+ *
+ * This prevents all writes to the buffer. Any attempt to write
+ * to the buffer after this will fail and return NULL.
+ *
+ * This is different than ring_buffer_record_disable() as
+ * it works like an on/off switch, where as the disable() version
+ * must be paired with a enable().
+ */
+void ring_buffer_record_off(struct trace_buffer *buffer)
+{
+	unsigned int rd;
+	unsigned int new_rd;
+
+	do {
+		rd = atomic_read(&buffer->record_disabled);
+		new_rd = rd | RB_BUFFER_OFF;
+	} while (atomic_cmpxchg(&buffer->record_disabled, rd, new_rd) != rd);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_record_off);
+
+/**
+ * ring_buffer_record_on - restart writes into the buffer
+ * @buffer: The ring buffer to start writes to.
+ *
+ * This enables all writes to the buffer that was disabled by
+ * ring_buffer_record_off().
+ *
+ * This is different than ring_buffer_record_enable() as
+ * it works like an on/off switch, where as the enable() version
+ * must be paired with a disable().
+ */
+void ring_buffer_record_on(struct trace_buffer *buffer)
+{
+	unsigned int rd;
+	unsigned int new_rd;
+
+	do {
+		rd = atomic_read(&buffer->record_disabled);
+		new_rd = rd & ~RB_BUFFER_OFF;
+	} while (atomic_cmpxchg(&buffer->record_disabled, rd, new_rd) != rd);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_record_on);
+
+/**
+ * ring_buffer_record_is_on - return true if the ring buffer can write
+ * @buffer: The ring buffer to see if write is enabled
+ *
+ * Returns true if the ring buffer is in a state that it accepts writes.
+ */
+bool ring_buffer_record_is_on(struct trace_buffer *buffer)
+{
+	return !atomic_read(&buffer->record_disabled);
+}
+
+/**
+ * ring_buffer_record_is_set_on - return true if the ring buffer is set writable
+ * @buffer: The ring buffer to see if write is set enabled
+ *
+ * Returns true if the ring buffer is set writable by ring_buffer_record_on().
+ * Note that this does NOT mean it is in a writable state.
+ *
+ * It may return true when the ring buffer has been disabled by
+ * ring_buffer_record_disable(), as that is a temporary disabling of
+ * the ring buffer.
+ */
+bool ring_buffer_record_is_set_on(struct trace_buffer *buffer)
+{
+	return !(atomic_read(&buffer->record_disabled) & RB_BUFFER_OFF);
+}
+
+/**
+ * ring_buffer_record_disable_cpu - stop all writes into the cpu_buffer
+ * @buffer: The ring buffer to stop writes to.
+ * @cpu: The CPU buffer to stop
+ *
+ * This prevents all writes to the buffer. Any attempt to write
+ * to the buffer after this will fail and return NULL.
+ *
+ * The caller should call synchronize_rcu() after this.
+ */
+void ring_buffer_record_disable_cpu(struct trace_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return;
+
+	cpu_buffer = buffer->buffers[cpu];
+	atomic_inc(&cpu_buffer->record_disabled);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_record_disable_cpu);
+
+/**
+ * ring_buffer_record_enable_cpu - enable writes to the buffer
+ * @buffer: The ring buffer to enable writes
+ * @cpu: The CPU to enable.
+ *
+ * Note, multiple disables will need the same number of enables
+ * to truly enable the writing (much like preempt_disable).
+ */
+void ring_buffer_record_enable_cpu(struct trace_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return;
+
+	cpu_buffer = buffer->buffers[cpu];
+	atomic_dec(&cpu_buffer->record_disabled);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_record_enable_cpu);
+
+/*
+ * The total entries in the ring buffer is the running counter
+ * of entries entered into the ring buffer, minus the sum of
+ * the entries read from the ring buffer and the number of
+ * entries that were overwritten.
+ */
+static inline unsigned long
+rb_num_of_entries(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	return local_read(&cpu_buffer->entries) -
+		(local_read(&cpu_buffer->overrun) + cpu_buffer->read);
+}
+
+/**
+ * ring_buffer_oldest_event_ts - get the oldest event timestamp from the buffer
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to read from.
+ */
+u64 ring_buffer_oldest_event_ts(struct trace_buffer *buffer, int cpu)
+{
+	unsigned long flags;
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct buffer_page *bpage;
+	u64 ret = 0;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return 0;
+
+	cpu_buffer = buffer->buffers[cpu];
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	/*
+	 * if the tail is on reader_page, oldest time stamp is on the reader
+	 * page
+	 */
+	if (cpu_buffer->tail_page == cpu_buffer->reader_page)
+		bpage = cpu_buffer->reader_page;
+	else
+		bpage = rb_set_head_page(cpu_buffer);
+	if (bpage)
+		ret = bpage->page->time_stamp;
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_oldest_event_ts);
+
+/**
+ * ring_buffer_bytes_cpu - get the number of bytes unconsumed in a cpu buffer
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to read from.
+ */
+unsigned long ring_buffer_bytes_cpu(struct trace_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long ret;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return 0;
+
+	cpu_buffer = buffer->buffers[cpu];
+	ret = local_read(&cpu_buffer->entries_bytes) - cpu_buffer->read_bytes;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_bytes_cpu);
+
+/**
+ * ring_buffer_entries_cpu - get the number of entries in a cpu buffer
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to get the entries from.
+ */
+unsigned long ring_buffer_entries_cpu(struct trace_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return 0;
+
+	cpu_buffer = buffer->buffers[cpu];
+
+	return rb_num_of_entries(cpu_buffer);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_entries_cpu);
+
+/**
+ * ring_buffer_overrun_cpu - get the number of overruns caused by the ring
+ * buffer wrapping around (only if RB_FL_OVERWRITE is on).
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to get the number of overruns from
+ */
+unsigned long ring_buffer_overrun_cpu(struct trace_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long ret;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return 0;
+
+	cpu_buffer = buffer->buffers[cpu];
+	ret = local_read(&cpu_buffer->overrun);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_overrun_cpu);
+
+/**
+ * ring_buffer_commit_overrun_cpu - get the number of overruns caused by
+ * commits failing due to the buffer wrapping around while there are uncommitted
+ * events, such as during an interrupt storm.
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to get the number of overruns from
+ */
+unsigned long
+ring_buffer_commit_overrun_cpu(struct trace_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long ret;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return 0;
+
+	cpu_buffer = buffer->buffers[cpu];
+	ret = local_read(&cpu_buffer->commit_overrun);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_commit_overrun_cpu);
+
+/**
+ * ring_buffer_dropped_events_cpu - get the number of dropped events caused by
+ * the ring buffer filling up (only if RB_FL_OVERWRITE is off).
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to get the number of overruns from
+ */
+unsigned long
+ring_buffer_dropped_events_cpu(struct trace_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long ret;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return 0;
+
+	cpu_buffer = buffer->buffers[cpu];
+	ret = local_read(&cpu_buffer->dropped_events);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_dropped_events_cpu);
+
+/**
+ * ring_buffer_read_events_cpu - get the number of events successfully read
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to get the number of events read
+ */
+unsigned long
+ring_buffer_read_events_cpu(struct trace_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return 0;
+
+	cpu_buffer = buffer->buffers[cpu];
+	return cpu_buffer->read;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_read_events_cpu);
+
+/**
+ * ring_buffer_entries - get the number of entries in a buffer
+ * @buffer: The ring buffer
+ *
+ * Returns the total number of entries in the ring buffer
+ * (all CPU entries)
+ */
+unsigned long ring_buffer_entries(struct trace_buffer *buffer)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long entries = 0;
+	int cpu;
+
+	/* if you care about this being correct, lock the buffer */
+	for_each_buffer_cpu(buffer, cpu) {
+		cpu_buffer = buffer->buffers[cpu];
+		entries += rb_num_of_entries(cpu_buffer);
+	}
+
+	return entries;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_entries);
+
+/**
+ * ring_buffer_overruns - get the number of overruns in buffer
+ * @buffer: The ring buffer
+ *
+ * Returns the total number of overruns in the ring buffer
+ * (all CPU entries)
+ */
+unsigned long ring_buffer_overruns(struct trace_buffer *buffer)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long overruns = 0;
+	int cpu;
+
+	/* if you care about this being correct, lock the buffer */
+	for_each_buffer_cpu(buffer, cpu) {
+		cpu_buffer = buffer->buffers[cpu];
+		overruns += local_read(&cpu_buffer->overrun);
+	}
+
+	return overruns;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_overruns);
+
+static void rb_iter_reset(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+
+	/* Iterator usage is expected to have record disabled */
+	iter->head_page = cpu_buffer->reader_page;
+	iter->head = cpu_buffer->reader_page->read;
+	iter->next_event = iter->head;
+
+	iter->cache_reader_page = iter->head_page;
+	iter->cache_read = cpu_buffer->read;
+	iter->cache_pages_removed = cpu_buffer->pages_removed;
+
+	if (iter->head) {
+		iter->read_stamp = cpu_buffer->read_stamp;
+		iter->page_stamp = cpu_buffer->reader_page->page->time_stamp;
+	} else {
+		iter->read_stamp = iter->head_page->page->time_stamp;
+		iter->page_stamp = iter->read_stamp;
+	}
+}
+
+/**
+ * ring_buffer_iter_reset - reset an iterator
+ * @iter: The iterator to reset
+ *
+ * Resets the iterator, so that it will start from the beginning
+ * again.
+ */
+void ring_buffer_iter_reset(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long flags;
+
+	if (!iter)
+		return;
+
+	cpu_buffer = iter->cpu_buffer;
+
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	rb_iter_reset(iter);
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_iter_reset);
+
+/**
+ * ring_buffer_iter_empty - check if an iterator has no more to read
+ * @iter: The iterator to check
+ */
+int ring_buffer_iter_empty(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct buffer_page *reader;
+	struct buffer_page *head_page;
+	struct buffer_page *commit_page;
+	struct buffer_page *curr_commit_page;
+	unsigned commit;
+	u64 curr_commit_ts;
+	u64 commit_ts;
+
+	cpu_buffer = iter->cpu_buffer;
+	reader = cpu_buffer->reader_page;
+	head_page = cpu_buffer->head_page;
+	commit_page = cpu_buffer->commit_page;
+	commit_ts = commit_page->page->time_stamp;
+
+	/*
+	 * When the writer goes across pages, it issues a cmpxchg which
+	 * is a mb(), which will synchronize with the rmb here.
+	 * (see rb_tail_page_update())
+	 */
+	smp_rmb();
+	commit = rb_page_commit(commit_page);
+	/* We want to make sure that the commit page doesn't change */
+	smp_rmb();
+
+	/* Make sure commit page didn't change */
+	curr_commit_page = READ_ONCE(cpu_buffer->commit_page);
+	curr_commit_ts = READ_ONCE(curr_commit_page->page->time_stamp);
+
+	/* If the commit page changed, then there's more data */
+	if (curr_commit_page != commit_page ||
+	    curr_commit_ts != commit_ts)
+		return 0;
+
+	/* Still racy, as it may return a false positive, but that's OK */
+	return ((iter->head_page == commit_page && iter->head >= commit) ||
+		(iter->head_page == reader && commit_page == head_page &&
+		 head_page->read == commit &&
+		 iter->head == rb_page_commit(cpu_buffer->reader_page)));
+}
+EXPORT_SYMBOL_GPL(ring_buffer_iter_empty);
+
+static void
+rb_update_read_stamp(struct ring_buffer_per_cpu *cpu_buffer,
+		     struct ring_buffer_event *event)
+{
+	u64 delta;
+
+	switch (event->type_len) {
+	case RINGBUF_TYPE_PADDING:
+		return;
+
+	case RINGBUF_TYPE_TIME_EXTEND:
+		delta = rb_event_time_stamp(event);
+		cpu_buffer->read_stamp += delta;
+		return;
+
+	case RINGBUF_TYPE_TIME_STAMP:
+		delta = rb_event_time_stamp(event);
+		delta = rb_fix_abs_ts(delta, cpu_buffer->read_stamp);
+		cpu_buffer->read_stamp = delta;
+		return;
+
+	case RINGBUF_TYPE_DATA:
+		cpu_buffer->read_stamp += event->time_delta;
+		return;
+
+	default:
+		RB_WARN_ON(cpu_buffer, 1);
+	}
+	return;
+}
+
+static void
+rb_update_iter_read_stamp(struct ring_buffer_iter *iter,
+			  struct ring_buffer_event *event)
+{
+	u64 delta;
+
+	switch (event->type_len) {
+	case RINGBUF_TYPE_PADDING:
+		return;
+
+	case RINGBUF_TYPE_TIME_EXTEND:
+		delta = rb_event_time_stamp(event);
+		iter->read_stamp += delta;
+		return;
+
+	case RINGBUF_TYPE_TIME_STAMP:
+		delta = rb_event_time_stamp(event);
+		delta = rb_fix_abs_ts(delta, iter->read_stamp);
+		iter->read_stamp = delta;
+		return;
+
+	case RINGBUF_TYPE_DATA:
+		iter->read_stamp += event->time_delta;
+		return;
+
+	default:
+		RB_WARN_ON(iter->cpu_buffer, 1);
+	}
+	return;
+}
+
+static struct buffer_page *
+rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct buffer_page *reader = NULL;
+	unsigned long overwrite;
+	unsigned long flags;
+	int nr_loops = 0;
+	int ret;
+
+	local_irq_save(flags);
+	arch_spin_lock(&cpu_buffer->lock);
+
+ again:
+	/*
+	 * This should normally only loop twice. But because the
+	 * start of the reader inserts an empty page, it causes
+	 * a case where we will loop three times. There should be no
+	 * reason to loop four times (that I know of).
+	 */
+	if (RB_WARN_ON(cpu_buffer, ++nr_loops > 3)) {
+		reader = NULL;
+		goto out;
+	}
+
+	reader = cpu_buffer->reader_page;
+
+	/* If there's more to read, return this page */
+	if (cpu_buffer->reader_page->read < rb_page_size(reader))
+		goto out;
+
+	/* Never should we have an index greater than the size */
+	if (RB_WARN_ON(cpu_buffer,
+		       cpu_buffer->reader_page->read > rb_page_size(reader)))
+		goto out;
+
+	/* check if we caught up to the tail */
+	reader = NULL;
+	if (cpu_buffer->commit_page == cpu_buffer->reader_page)
+		goto out;
+
+	/* Don't bother swapping if the ring buffer is empty */
+	if (rb_num_of_entries(cpu_buffer) == 0)
+		goto out;
+
+	/*
+	 * Reset the reader page to size zero.
+	 */
+	local_set(&cpu_buffer->reader_page->write, 0);
+	local_set(&cpu_buffer->reader_page->entries, 0);
+	local_set(&cpu_buffer->reader_page->page->commit, 0);
+	cpu_buffer->reader_page->real_end = 0;
+
+ spin:
+	/*
+	 * Splice the empty reader page into the list around the head.
+	 */
+	reader = rb_set_head_page(cpu_buffer);
+	if (!reader)
+		goto out;
+	cpu_buffer->reader_page->list.next = rb_list_head(reader->list.next);
+	cpu_buffer->reader_page->list.prev = reader->list.prev;
+
+	/*
+	 * cpu_buffer->pages just needs to point to the buffer, it
+	 *  has no specific buffer page to point to. Lets move it out
+	 *  of our way so we don't accidentally swap it.
+	 */
+	cpu_buffer->pages = reader->list.prev;
+
+	/* The reader page will be pointing to the new head */
+	rb_set_list_to_head(&cpu_buffer->reader_page->list);
+
+	/*
+	 * We want to make sure we read the overruns after we set up our
+	 * pointers to the next object. The writer side does a
+	 * cmpxchg to cross pages which acts as the mb on the writer
+	 * side. Note, the reader will constantly fail the swap
+	 * while the writer is updating the pointers, so this
+	 * guarantees that the overwrite recorded here is the one we
+	 * want to compare with the last_overrun.
+	 */
+	smp_mb();
+	overwrite = local_read(&(cpu_buffer->overrun));
+
+	/*
+	 * Here's the tricky part.
+	 *
+	 * We need to move the pointer past the header page.
+	 * But we can only do that if a writer is not currently
+	 * moving it. The page before the header page has the
+	 * flag bit '1' set if it is pointing to the page we want.
+	 * but if the writer is in the process of moving it
+	 * than it will be '2' or already moved '0'.
+	 */
+
+	ret = rb_head_page_replace(reader, cpu_buffer->reader_page);
+
+	/*
+	 * If we did not convert it, then we must try again.
+	 */
+	if (!ret)
+		goto spin;
+
+	/*
+	 * Yay! We succeeded in replacing the page.
+	 *
+	 * Now make the new head point back to the reader page.
+	 */
+	rb_list_head(reader->list.next)->prev = &cpu_buffer->reader_page->list;
+	rb_inc_page(&cpu_buffer->head_page);
+
+	local_inc(&cpu_buffer->pages_read);
+
+	/* Finally update the reader page to the new head */
+	cpu_buffer->reader_page = reader;
+	cpu_buffer->reader_page->read = 0;
+
+	if (overwrite != cpu_buffer->last_overrun) {
+		cpu_buffer->lost_events = overwrite - cpu_buffer->last_overrun;
+		cpu_buffer->last_overrun = overwrite;
+	}
+
+	goto again;
+
+ out:
+	/* Update the read_stamp on the first event */
+	if (reader && reader->read == 0)
+		cpu_buffer->read_stamp = reader->page->time_stamp;
+
+	arch_spin_unlock(&cpu_buffer->lock);
+	local_irq_restore(flags);
+
+	/*
+	 * The writer has preempt disable, wait for it. But not forever
+	 * Although, 1 second is pretty much "forever"
+	 */
+#define USECS_WAIT	1000000
+        for (nr_loops = 0; nr_loops < USECS_WAIT; nr_loops++) {
+		/* If the write is past the end of page, a writer is still updating it */
+		if (likely(!reader || rb_page_write(reader) <= BUF_PAGE_SIZE))
+			break;
+
+		udelay(1);
+
+		/* Get the latest version of the reader write value */
+		smp_rmb();
+	}
+
+	/* The writer is not moving forward? Something is wrong */
+	if (RB_WARN_ON(cpu_buffer, nr_loops == USECS_WAIT))
+		reader = NULL;
+
+	/*
+	 * Make sure we see any padding after the write update
+	 * (see rb_reset_tail()).
+	 *
+	 * In addition, a writer may be writing on the reader page
+	 * if the page has not been fully filled, so the read barrier
+	 * is also needed to make sure we see the content of what is
+	 * committed by the writer (see rb_set_commit_to_write()).
+	 */
+	smp_rmb();
+
+
+	return reader;
+}
+
+static void rb_advance_reader(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct ring_buffer_event *event;
+	struct buffer_page *reader;
+	unsigned length;
+
+	reader = rb_get_reader_page(cpu_buffer);
+
+	/* This function should not be called when buffer is empty */
+	if (RB_WARN_ON(cpu_buffer, !reader))
+		return;
+
+	event = rb_reader_event(cpu_buffer);
+
+	if (event->type_len <= RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
+		cpu_buffer->read++;
+
+	rb_update_read_stamp(cpu_buffer, event);
+
+	length = rb_event_length(event);
+	cpu_buffer->reader_page->read += length;
+	cpu_buffer->read_bytes += length;
+}
+
+static void rb_advance_iter(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+
+	cpu_buffer = iter->cpu_buffer;
+
+	/* If head == next_event then we need to jump to the next event */
+	if (iter->head == iter->next_event) {
+		/* If the event gets overwritten again, there's nothing to do */
+		if (rb_iter_head_event(iter) == NULL)
+			return;
+	}
+
+	iter->head = iter->next_event;
+
+	/*
+	 * Check if we are at the end of the buffer.
+	 */
+	if (iter->next_event >= rb_page_size(iter->head_page)) {
+		/* discarded commits can make the page empty */
+		if (iter->head_page == cpu_buffer->commit_page)
+			return;
+		rb_inc_iter(iter);
+		return;
+	}
+
+	rb_update_iter_read_stamp(iter, iter->event);
+}
+
+static int rb_lost_events(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	return cpu_buffer->lost_events;
+}
+
+static struct ring_buffer_event *
+rb_buffer_peek(struct ring_buffer_per_cpu *cpu_buffer, u64 *ts,
+	       unsigned long *lost_events)
+{
+	struct ring_buffer_event *event;
+	struct buffer_page *reader;
+	int nr_loops = 0;
+
+	if (ts)
+		*ts = 0;
+ again:
+	/*
+	 * We repeat when a time extend is encountered.
+	 * Since the time extend is always attached to a data event,
+	 * we should never loop more than once.
+	 * (We never hit the following condition more than twice).
+	 */
+	if (RB_WARN_ON(cpu_buffer, ++nr_loops > 2))
+		return NULL;
+
+	reader = rb_get_reader_page(cpu_buffer);
+	if (!reader)
+		return NULL;
+
+	event = rb_reader_event(cpu_buffer);
+
+	switch (event->type_len) {
+	case RINGBUF_TYPE_PADDING:
+		if (rb_null_event(event))
+			RB_WARN_ON(cpu_buffer, 1);
+		/*
+		 * Because the writer could be discarding every
+		 * event it creates (which would probably be bad)
+		 * if we were to go back to "again" then we may never
+		 * catch up, and will trigger the warn on, or lock
+		 * the box. Return the padding, and we will release
+		 * the current locks, and try again.
+		 */
+		return event;
+
+	case RINGBUF_TYPE_TIME_EXTEND:
+		/* Internal data, OK to advance */
+		rb_advance_reader(cpu_buffer);
+		goto again;
+
+	case RINGBUF_TYPE_TIME_STAMP:
+		if (ts) {
+			*ts = rb_event_time_stamp(event);
+			*ts = rb_fix_abs_ts(*ts, reader->page->time_stamp);
+			ring_buffer_normalize_time_stamp(cpu_buffer->buffer,
+							 cpu_buffer->cpu, ts);
+		}
+		/* Internal data, OK to advance */
+		rb_advance_reader(cpu_buffer);
+		goto again;
+
+	case RINGBUF_TYPE_DATA:
+		if (ts && !(*ts)) {
+			*ts = cpu_buffer->read_stamp + event->time_delta;
+			ring_buffer_normalize_time_stamp(cpu_buffer->buffer,
+							 cpu_buffer->cpu, ts);
+		}
+		if (lost_events)
+			*lost_events = rb_lost_events(cpu_buffer);
+		return event;
+
+	default:
+		RB_WARN_ON(cpu_buffer, 1);
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_peek);
+
+static struct ring_buffer_event *
+rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
+{
+	struct trace_buffer *buffer;
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct ring_buffer_event *event;
+	int nr_loops = 0;
+
+	if (ts)
+		*ts = 0;
+
+	cpu_buffer = iter->cpu_buffer;
+	buffer = cpu_buffer->buffer;
+
+	/*
+	 * Check if someone performed a consuming read to the buffer
+	 * or removed some pages from the buffer. In these cases,
+	 * iterator was invalidated and we need to reset it.
+	 */
+	if (unlikely(iter->cache_read != cpu_buffer->read ||
+		     iter->cache_reader_page != cpu_buffer->reader_page ||
+		     iter->cache_pages_removed != cpu_buffer->pages_removed))
+		rb_iter_reset(iter);
+
+ again:
+	if (ring_buffer_iter_empty(iter))
+		return NULL;
+
+	/*
+	 * As the writer can mess with what the iterator is trying
+	 * to read, just give up if we fail to get an event after
+	 * three tries. The iterator is not as reliable when reading
+	 * the ring buffer with an active write as the consumer is.
+	 * Do not warn if the three failures is reached.
+	 */
+	if (++nr_loops > 3)
+		return NULL;
+
+	if (rb_per_cpu_empty(cpu_buffer))
+		return NULL;
+
+	if (iter->head >= rb_page_size(iter->head_page)) {
+		rb_inc_iter(iter);
+		goto again;
+	}
+
+	event = rb_iter_head_event(iter);
+	if (!event)
+		goto again;
+
+	switch (event->type_len) {
+	case RINGBUF_TYPE_PADDING:
+		if (rb_null_event(event)) {
+			rb_inc_iter(iter);
+			goto again;
+		}
+		rb_advance_iter(iter);
+		return event;
+
+	case RINGBUF_TYPE_TIME_EXTEND:
+		/* Internal data, OK to advance */
+		rb_advance_iter(iter);
+		goto again;
+
+	case RINGBUF_TYPE_TIME_STAMP:
+		if (ts) {
+			*ts = rb_event_time_stamp(event);
+			*ts = rb_fix_abs_ts(*ts, iter->head_page->page->time_stamp);
+			ring_buffer_normalize_time_stamp(cpu_buffer->buffer,
+							 cpu_buffer->cpu, ts);
+		}
+		/* Internal data, OK to advance */
+		rb_advance_iter(iter);
+		goto again;
+
+	case RINGBUF_TYPE_DATA:
+		if (ts && !(*ts)) {
+			*ts = iter->read_stamp + event->time_delta;
+			ring_buffer_normalize_time_stamp(buffer,
+							 cpu_buffer->cpu, ts);
+		}
+		return event;
+
+	default:
+		RB_WARN_ON(cpu_buffer, 1);
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_iter_peek);
+
+static inline bool rb_reader_lock(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	if (likely(!in_nmi())) {
+		raw_spin_lock(&cpu_buffer->reader_lock);
+		return true;
+	}
+
+	/*
+	 * If an NMI die dumps out the content of the ring buffer
+	 * trylock must be used to prevent a deadlock if the NMI
+	 * preempted a task that holds the ring buffer locks. If
+	 * we get the lock then all is fine, if not, then continue
+	 * to do the read, but this can corrupt the ring buffer,
+	 * so it must be permanently disabled from future writes.
+	 * Reading from NMI is a oneshot deal.
+	 */
+	if (raw_spin_trylock(&cpu_buffer->reader_lock))
+		return true;
+
+	/* Continue without locking, but disable the ring buffer */
+	atomic_inc(&cpu_buffer->record_disabled);
+	return false;
+}
+
+static inline void
+rb_reader_unlock(struct ring_buffer_per_cpu *cpu_buffer, bool locked)
+{
+	if (likely(locked))
+		raw_spin_unlock(&cpu_buffer->reader_lock);
+	return;
+}
+
+/**
+ * ring_buffer_peek - peek at the next event to be read
+ * @buffer: The ring buffer to read
+ * @cpu: The cpu to peak at
+ * @ts: The timestamp counter of this event.
+ * @lost_events: a variable to store if events were lost (may be NULL)
+ *
+ * This will return the event that will be read next, but does
+ * not consume the data.
+ */
+struct ring_buffer_event *
+ring_buffer_peek(struct trace_buffer *buffer, int cpu, u64 *ts,
+		 unsigned long *lost_events)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+	struct ring_buffer_event *event;
+	unsigned long flags;
+	bool dolock;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return NULL;
+
+ again:
+	local_irq_save(flags);
+	dolock = rb_reader_lock(cpu_buffer);
+	event = rb_buffer_peek(cpu_buffer, ts, lost_events);
+	if (event && event->type_len == RINGBUF_TYPE_PADDING)
+		rb_advance_reader(cpu_buffer);
+	rb_reader_unlock(cpu_buffer, dolock);
+	local_irq_restore(flags);
+
+	if (event && event->type_len == RINGBUF_TYPE_PADDING)
+		goto again;
+
+	return event;
+}
+
+/** ring_buffer_iter_dropped - report if there are dropped events
+ * @iter: The ring buffer iterator
+ *
+ * Returns true if there was dropped events since the last peek.
+ */
+bool ring_buffer_iter_dropped(struct ring_buffer_iter *iter)
+{
+	bool ret = iter->missed_events != 0;
+
+	iter->missed_events = 0;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_iter_dropped);
+
+/**
+ * ring_buffer_iter_peek - peek at the next event to be read
+ * @iter: The ring buffer iterator
+ * @ts: The timestamp counter of this event.
+ *
+ * This will return the event that will be read next, but does
+ * not increment the iterator.
+ */
+struct ring_buffer_event *
+ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+	struct ring_buffer_event *event;
+	unsigned long flags;
+
+ again:
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	event = rb_iter_peek(iter, ts);
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+	if (event && event->type_len == RINGBUF_TYPE_PADDING)
+		goto again;
+
+	return event;
+}
+
+/**
+ * ring_buffer_consume - return an event and consume it
+ * @buffer: The ring buffer to get the next event from
+ * @cpu: the cpu to read the buffer from
+ * @ts: a variable to store the timestamp (may be NULL)
+ * @lost_events: a variable to store if events were lost (may be NULL)
+ *
+ * Returns the next event in the ring buffer, and that event is consumed.
+ * Meaning, that sequential reads will keep returning a different event,
+ * and eventually empty the ring buffer if the producer is slower.
+ */
+struct ring_buffer_event *
+ring_buffer_consume(struct trace_buffer *buffer, int cpu, u64 *ts,
+		    unsigned long *lost_events)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct ring_buffer_event *event = NULL;
+	unsigned long flags;
+	bool dolock;
+
+ again:
+	/* might be called in atomic */
+	preempt_disable();
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		goto out;
+
+	cpu_buffer = buffer->buffers[cpu];
+	local_irq_save(flags);
+	dolock = rb_reader_lock(cpu_buffer);
+
+	event = rb_buffer_peek(cpu_buffer, ts, lost_events);
+	if (event) {
+		cpu_buffer->lost_events = 0;
+		rb_advance_reader(cpu_buffer);
+	}
+
+	rb_reader_unlock(cpu_buffer, dolock);
+	local_irq_restore(flags);
+
+ out:
+	preempt_enable();
+
+	if (event && event->type_len == RINGBUF_TYPE_PADDING)
+		goto again;
+
+	return event;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_consume);
+
+/**
+ * ring_buffer_read_prepare - Prepare for a non consuming read of the buffer
+ * @buffer: The ring buffer to read from
+ * @cpu: The cpu buffer to iterate over
+ * @flags: gfp flags to use for memory allocation
+ *
+ * This performs the initial preparations necessary to iterate
+ * through the buffer.  Memory is allocated, buffer recording
+ * is disabled, and the iterator pointer is returned to the caller.
+ *
+ * Disabling buffer recording prevents the reading from being
+ * corrupted. This is not a consuming read, so a producer is not
+ * expected.
+ *
+ * After a sequence of ring_buffer_read_prepare calls, the user is
+ * expected to make at least one call to ring_buffer_read_prepare_sync.
+ * Afterwards, ring_buffer_read_start is invoked to get things going
+ * for real.
+ *
+ * This overall must be paired with ring_buffer_read_finish.
+ */
+struct ring_buffer_iter *
+ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct ring_buffer_iter *iter;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return NULL;
+
+	iter = kzalloc(sizeof(*iter), flags);
+	if (!iter)
+		return NULL;
+
+	/* Holds the entire event: data and meta data */
+	iter->event = kmalloc(BUF_PAGE_SIZE, flags);
+	if (!iter->event) {
+		kfree(iter);
+		return NULL;
+	}
+
+	cpu_buffer = buffer->buffers[cpu];
+
+	iter->cpu_buffer = cpu_buffer;
+
+	atomic_inc(&cpu_buffer->resize_disabled);
+
+	return iter;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_read_prepare);
+
+/**
+ * ring_buffer_read_prepare_sync - Synchronize a set of prepare calls
+ *
+ * All previously invoked ring_buffer_read_prepare calls to prepare
+ * iterators will be synchronized.  Afterwards, read_buffer_read_start
+ * calls on those iterators are allowed.
+ */
+void
+ring_buffer_read_prepare_sync(void)
+{
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(ring_buffer_read_prepare_sync);
+
+/**
+ * ring_buffer_read_start - start a non consuming read of the buffer
+ * @iter: The iterator returned by ring_buffer_read_prepare
+ *
+ * This finalizes the startup of an iteration through the buffer.
+ * The iterator comes from a call to ring_buffer_read_prepare and
+ * an intervening ring_buffer_read_prepare_sync must have been
+ * performed.
+ *
+ * Must be paired with ring_buffer_read_finish.
+ */
+void
+ring_buffer_read_start(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long flags;
+
+	if (!iter)
+		return;
+
+	cpu_buffer = iter->cpu_buffer;
+
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	arch_spin_lock(&cpu_buffer->lock);
+	rb_iter_reset(iter);
+	arch_spin_unlock(&cpu_buffer->lock);
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_read_start);
+
+/**
+ * ring_buffer_read_finish - finish reading the iterator of the buffer
+ * @iter: The iterator retrieved by ring_buffer_start
+ *
+ * This re-enables the recording to the buffer, and frees the
+ * iterator.
+ */
+void
+ring_buffer_read_finish(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+	unsigned long flags;
+
+	/*
+	 * Ring buffer is disabled from recording, here's a good place
+	 * to check the integrity of the ring buffer.
+	 * Must prevent readers from trying to read, as the check
+	 * clears the HEAD page and readers require it.
+	 */
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	rb_check_pages(cpu_buffer);
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+	atomic_dec(&cpu_buffer->resize_disabled);
+	kfree(iter->event);
+	kfree(iter);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_read_finish);
+
+/**
+ * ring_buffer_iter_advance - advance the iterator to the next location
+ * @iter: The ring buffer iterator
+ *
+ * Move the location of the iterator such that the next read will
+ * be the next location of the iterator.
+ */
+void ring_buffer_iter_advance(struct ring_buffer_iter *iter)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+
+	rb_advance_iter(iter);
+
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_iter_advance);
+
+/**
+ * ring_buffer_size - return the size of the ring buffer (in bytes)
+ * @buffer: The ring buffer.
+ * @cpu: The CPU to get ring buffer size from.
+ */
+unsigned long ring_buffer_size(struct trace_buffer *buffer, int cpu)
+{
+	/*
+	 * Earlier, this method returned
+	 *	BUF_PAGE_SIZE * buffer->nr_pages
+	 * Since the nr_pages field is now removed, we have converted this to
+	 * return the per cpu buffer value.
+	 */
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return 0;
+
+	return BUF_PAGE_SIZE * buffer->buffers[cpu]->nr_pages;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_size);
+
+static void rb_clear_buffer_page(struct buffer_page *page)
+{
+	local_set(&page->write, 0);
+	local_set(&page->entries, 0);
+	rb_init_page(page->page);
+	page->read = 0;
+}
+
+static void
+rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	struct buffer_page *page;
+
+	rb_head_page_deactivate(cpu_buffer);
+
+	cpu_buffer->head_page
+		= list_entry(cpu_buffer->pages, struct buffer_page, list);
+	rb_clear_buffer_page(cpu_buffer->head_page);
+	list_for_each_entry(page, cpu_buffer->pages, list) {
+		rb_clear_buffer_page(page);
+	}
+
+	cpu_buffer->tail_page = cpu_buffer->head_page;
+	cpu_buffer->commit_page = cpu_buffer->head_page;
+
+	INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
+	INIT_LIST_HEAD(&cpu_buffer->new_pages);
+	rb_clear_buffer_page(cpu_buffer->reader_page);
+
+	local_set(&cpu_buffer->entries_bytes, 0);
+	local_set(&cpu_buffer->overrun, 0);
+	local_set(&cpu_buffer->commit_overrun, 0);
+	local_set(&cpu_buffer->dropped_events, 0);
+	local_set(&cpu_buffer->entries, 0);
+	local_set(&cpu_buffer->committing, 0);
+	local_set(&cpu_buffer->commits, 0);
+	local_set(&cpu_buffer->pages_touched, 0);
+	local_set(&cpu_buffer->pages_lost, 0);
+	local_set(&cpu_buffer->pages_read, 0);
+	cpu_buffer->last_pages_touch = 0;
+	cpu_buffer->shortest_full = 0;
+	cpu_buffer->read = 0;
+	cpu_buffer->read_bytes = 0;
+
+	rb_time_set(&cpu_buffer->write_stamp, 0);
+	rb_time_set(&cpu_buffer->before_stamp, 0);
+
+	memset(cpu_buffer->event_stamp, 0, sizeof(cpu_buffer->event_stamp));
+
+	cpu_buffer->lost_events = 0;
+	cpu_buffer->last_overrun = 0;
+
+	rb_head_page_activate(cpu_buffer);
+	cpu_buffer->pages_removed = 0;
+}
+
+/* Must have disabled the cpu buffer then done a synchronize_rcu */
+static void reset_disabled_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+
+	if (RB_WARN_ON(cpu_buffer, local_read(&cpu_buffer->committing)))
+		goto out;
+
+	arch_spin_lock(&cpu_buffer->lock);
+
+	rb_reset_cpu(cpu_buffer);
+
+	arch_spin_unlock(&cpu_buffer->lock);
+
+ out:
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+}
+
+/**
+ * ring_buffer_reset_cpu - reset a ring buffer per CPU buffer
+ * @buffer: The ring buffer to reset a per cpu buffer of
+ * @cpu: The CPU buffer to be reset
+ */
+void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return;
+
+	/* prevent another thread from changing buffer sizes */
+	mutex_lock(&buffer->mutex);
+
+	atomic_inc(&cpu_buffer->resize_disabled);
+	atomic_inc(&cpu_buffer->record_disabled);
+
+	/* Make sure all commits have finished */
+	synchronize_rcu();
+
+	reset_disabled_cpu_buffer(cpu_buffer);
+
+	atomic_dec(&cpu_buffer->record_disabled);
+	atomic_dec(&cpu_buffer->resize_disabled);
+
+	mutex_unlock(&buffer->mutex);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_reset_cpu);
+
+/* Flag to ensure proper resetting of atomic variables */
+#define RESET_BIT	(1 << 30)
+
+/**
+ * ring_buffer_reset_online_cpus - reset a ring buffer per CPU buffer
+ * @buffer: The ring buffer to reset a per cpu buffer of
+ * @cpu: The CPU buffer to be reset
+ */
+void ring_buffer_reset_online_cpus(struct trace_buffer *buffer)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	int cpu;
+
+	/* prevent another thread from changing buffer sizes */
+	mutex_lock(&buffer->mutex);
+
+	for_each_online_buffer_cpu(buffer, cpu) {
+		cpu_buffer = buffer->buffers[cpu];
+
+		atomic_add(RESET_BIT, &cpu_buffer->resize_disabled);
+		atomic_inc(&cpu_buffer->record_disabled);
+	}
+
+	/* Make sure all commits have finished */
+	synchronize_rcu();
+
+	for_each_buffer_cpu(buffer, cpu) {
+		cpu_buffer = buffer->buffers[cpu];
+
+		/*
+		 * If a CPU came online during the synchronize_rcu(), then
+		 * ignore it.
+		 */
+		if (!(atomic_read(&cpu_buffer->resize_disabled) & RESET_BIT))
+			continue;
+
+		reset_disabled_cpu_buffer(cpu_buffer);
+
+		atomic_dec(&cpu_buffer->record_disabled);
+		atomic_sub(RESET_BIT, &cpu_buffer->resize_disabled);
+	}
+
+	mutex_unlock(&buffer->mutex);
+}
+
+/**
+ * ring_buffer_reset - reset a ring buffer
+ * @buffer: The ring buffer to reset all cpu buffers
+ */
+void ring_buffer_reset(struct trace_buffer *buffer)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	int cpu;
+
+	/* prevent another thread from changing buffer sizes */
+	mutex_lock(&buffer->mutex);
+
+	for_each_buffer_cpu(buffer, cpu) {
+		cpu_buffer = buffer->buffers[cpu];
+
+		atomic_inc(&cpu_buffer->resize_disabled);
+		atomic_inc(&cpu_buffer->record_disabled);
+	}
+
+	/* Make sure all commits have finished */
+	synchronize_rcu();
+
+	for_each_buffer_cpu(buffer, cpu) {
+		cpu_buffer = buffer->buffers[cpu];
+
+		reset_disabled_cpu_buffer(cpu_buffer);
+
+		atomic_dec(&cpu_buffer->record_disabled);
+		atomic_dec(&cpu_buffer->resize_disabled);
+	}
+
+	mutex_unlock(&buffer->mutex);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_reset);
+
+/**
+ * ring_buffer_empty - is the ring buffer empty?
+ * @buffer: The ring buffer to test
+ */
+bool ring_buffer_empty(struct trace_buffer *buffer)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long flags;
+	bool dolock;
+	int cpu;
+	int ret;
+
+	/* yes this is racy, but if you don't like the race, lock the buffer */
+	for_each_buffer_cpu(buffer, cpu) {
+		cpu_buffer = buffer->buffers[cpu];
+		local_irq_save(flags);
+		dolock = rb_reader_lock(cpu_buffer);
+		ret = rb_per_cpu_empty(cpu_buffer);
+		rb_reader_unlock(cpu_buffer, dolock);
+		local_irq_restore(flags);
+
+		if (!ret)
+			return false;
+	}
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_empty);
+
+/**
+ * ring_buffer_empty_cpu - is a cpu buffer of a ring buffer empty?
+ * @buffer: The ring buffer
+ * @cpu: The CPU buffer to test
+ */
+bool ring_buffer_empty_cpu(struct trace_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	unsigned long flags;
+	bool dolock;
+	int ret;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return true;
+
+	cpu_buffer = buffer->buffers[cpu];
+	local_irq_save(flags);
+	dolock = rb_reader_lock(cpu_buffer);
+	ret = rb_per_cpu_empty(cpu_buffer);
+	rb_reader_unlock(cpu_buffer, dolock);
+	local_irq_restore(flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_empty_cpu);
+
+#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
+/**
+ * ring_buffer_swap_cpu - swap a CPU buffer between two ring buffers
+ * @buffer_a: One buffer to swap with
+ * @buffer_b: The other buffer to swap with
+ * @cpu: the CPU of the buffers to swap
+ *
+ * This function is useful for tracers that want to take a "snapshot"
+ * of a CPU buffer and has another back up buffer lying around.
+ * it is expected that the tracer handles the cpu buffer not being
+ * used at the moment.
+ */
+int ring_buffer_swap_cpu(struct trace_buffer *buffer_a,
+			 struct trace_buffer *buffer_b, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer_a;
+	struct ring_buffer_per_cpu *cpu_buffer_b;
+	int ret = -EINVAL;
+
+	if (!cpumask_test_cpu(cpu, buffer_a->cpumask) ||
+	    !cpumask_test_cpu(cpu, buffer_b->cpumask))
+		goto out;
+
+	cpu_buffer_a = buffer_a->buffers[cpu];
+	cpu_buffer_b = buffer_b->buffers[cpu];
+
+	/* At least make sure the two buffers are somewhat the same */
+	if (cpu_buffer_a->nr_pages != cpu_buffer_b->nr_pages)
+		goto out;
+
+	ret = -EAGAIN;
+
+	if (atomic_read(&buffer_a->record_disabled))
+		goto out;
+
+	if (atomic_read(&buffer_b->record_disabled))
+		goto out;
+
+	if (atomic_read(&cpu_buffer_a->record_disabled))
+		goto out;
+
+	if (atomic_read(&cpu_buffer_b->record_disabled))
+		goto out;
+
+	/*
+	 * We can't do a synchronize_rcu here because this
+	 * function can be called in atomic context.
+	 * Normally this will be called from the same CPU as cpu.
+	 * If not it's up to the caller to protect this.
+	 */
+	atomic_inc(&cpu_buffer_a->record_disabled);
+	atomic_inc(&cpu_buffer_b->record_disabled);
+
+	ret = -EBUSY;
+	if (local_read(&cpu_buffer_a->committing))
+		goto out_dec;
+	if (local_read(&cpu_buffer_b->committing))
+		goto out_dec;
+
+	/*
+	 * When resize is in progress, we cannot swap it because
+	 * it will mess the state of the cpu buffer.
+	 */
+	if (atomic_read(&buffer_a->resizing))
+		goto out_dec;
+	if (atomic_read(&buffer_b->resizing))
+		goto out_dec;
+
+	buffer_a->buffers[cpu] = cpu_buffer_b;
+	buffer_b->buffers[cpu] = cpu_buffer_a;
+
+	cpu_buffer_b->buffer = buffer_a;
+	cpu_buffer_a->buffer = buffer_b;
+
+	ret = 0;
+
+out_dec:
+	atomic_dec(&cpu_buffer_a->record_disabled);
+	atomic_dec(&cpu_buffer_b->record_disabled);
+out:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu);
+#endif /* CONFIG_RING_BUFFER_ALLOW_SWAP */
+
+/**
+ * ring_buffer_alloc_read_page - allocate a page to read from buffer
+ * @buffer: the buffer to allocate for.
+ * @cpu: the cpu buffer to allocate.
+ *
+ * This function is used in conjunction with ring_buffer_read_page.
+ * When reading a full page from the ring buffer, these functions
+ * can be used to speed up the process. The calling function should
+ * allocate a few pages first with this function. Then when it
+ * needs to get pages from the ring buffer, it passes the result
+ * of this function into ring_buffer_read_page, which will swap
+ * the page that was allocated, with the read page of the buffer.
+ *
+ * Returns:
+ *  The page allocated, or ERR_PTR
+ */
+void *ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct buffer_data_page *bpage = NULL;
+	unsigned long flags;
+	struct page *page;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		return ERR_PTR(-ENODEV);
+
+	cpu_buffer = buffer->buffers[cpu];
+	local_irq_save(flags);
+	arch_spin_lock(&cpu_buffer->lock);
+
+	if (cpu_buffer->free_page) {
+		bpage = cpu_buffer->free_page;
+		cpu_buffer->free_page = NULL;
+	}
+
+	arch_spin_unlock(&cpu_buffer->lock);
+	local_irq_restore(flags);
+
+	if (bpage)
+		goto out;
+
+	page = alloc_pages_node(cpu_to_node(cpu),
+				GFP_KERNEL | __GFP_NORETRY, 0);
+	if (!page)
+		return ERR_PTR(-ENOMEM);
+
+	bpage = page_address(page);
+
+ out:
+	rb_init_page(bpage);
+
+	return bpage;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_alloc_read_page);
+
+/**
+ * ring_buffer_free_read_page - free an allocated read page
+ * @buffer: the buffer the page was allocate for
+ * @cpu: the cpu buffer the page came from
+ * @data: the page to free
+ *
+ * Free a page allocated from ring_buffer_alloc_read_page.
+ */
+void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, void *data)
+{
+	struct ring_buffer_per_cpu *cpu_buffer;
+	struct buffer_data_page *bpage = data;
+	struct page *page = virt_to_page(bpage);
+	unsigned long flags;
+
+	if (!buffer || !buffer->buffers || !buffer->buffers[cpu])
+		return;
+
+	cpu_buffer = buffer->buffers[cpu];
+
+	/* If the page is still in use someplace else, we can't reuse it */
+	if (page_ref_count(page) > 1)
+		goto out;
+
+	local_irq_save(flags);
+	arch_spin_lock(&cpu_buffer->lock);
+
+	if (!cpu_buffer->free_page) {
+		cpu_buffer->free_page = bpage;
+		bpage = NULL;
+	}
+
+	arch_spin_unlock(&cpu_buffer->lock);
+	local_irq_restore(flags);
+
+ out:
+	free_page((unsigned long)bpage);
+}
+EXPORT_SYMBOL_GPL(ring_buffer_free_read_page);
+
+/**
+ * ring_buffer_read_page - extract a page from the ring buffer
+ * @buffer: buffer to extract from
+ * @data_page: the page to use allocated from ring_buffer_alloc_read_page
+ * @len: amount to extract
+ * @cpu: the cpu of the buffer to extract
+ * @full: should the extraction only happen when the page is full.
+ *
+ * This function will pull out a page from the ring buffer and consume it.
+ * @data_page must be the address of the variable that was returned
+ * from ring_buffer_alloc_read_page. This is because the page might be used
+ * to swap with a page in the ring buffer.
+ *
+ * for example:
+ *	rpage = ring_buffer_alloc_read_page(buffer, cpu);
+ *	if (IS_ERR(rpage))
+ *		return PTR_ERR(rpage);
+ *	ret = ring_buffer_read_page(buffer, &rpage, len, cpu, 0);
+ *	if (ret >= 0)
+ *		process_page(rpage, ret);
+ *
+ * When @full is set, the function will not return true unless
+ * the writer is off the reader page.
+ *
+ * Note: it is up to the calling functions to handle sleeps and wakeups.
+ *  The ring buffer can be used anywhere in the kernel and can not
+ *  blindly call wake_up. The layer that uses the ring buffer must be
+ *  responsible for that.
+ *
+ * Returns:
+ *  >=0 if data has been transferred, returns the offset of consumed data.
+ *  <0 if no data has been transferred.
+ */
+int ring_buffer_read_page(struct trace_buffer *buffer,
+			  void **data_page, size_t len, int cpu, int full)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+	struct ring_buffer_event *event;
+	struct buffer_data_page *bpage;
+	struct buffer_page *reader;
+	unsigned long missed_events;
+	unsigned long flags;
+	unsigned int commit;
+	unsigned int read;
+	u64 save_timestamp;
+	int ret = -1;
+
+	if (!cpumask_test_cpu(cpu, buffer->cpumask))
+		goto out;
+
+	/*
+	 * If len is not big enough to hold the page header, then
+	 * we can not copy anything.
+	 */
+	if (len <= BUF_PAGE_HDR_SIZE)
+		goto out;
+
+	len -= BUF_PAGE_HDR_SIZE;
+
+	if (!data_page)
+		goto out;
+
+	bpage = *data_page;
+	if (!bpage)
+		goto out;
+
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+
+	reader = rb_get_reader_page(cpu_buffer);
+	if (!reader)
+		goto out_unlock;
+
+	event = rb_reader_event(cpu_buffer);
+
+	read = reader->read;
+	commit = rb_page_commit(reader);
+
+	/* Check if any events were dropped */
+	missed_events = cpu_buffer->lost_events;
+
+	/*
+	 * If this page has been partially read or
+	 * if len is not big enough to read the rest of the page or
+	 * a writer is still on the page, then
+	 * we must copy the data from the page to the buffer.
+	 * Otherwise, we can simply swap the page with the one passed in.
+	 */
+	if (read || (len < (commit - read)) ||
+	    cpu_buffer->reader_page == cpu_buffer->commit_page) {
+		struct buffer_data_page *rpage = cpu_buffer->reader_page->page;
+		unsigned int rpos = read;
+		unsigned int pos = 0;
+		unsigned int size;
+
+		/*
+		 * If a full page is expected, this can still be returned
+		 * if there's been a previous partial read and the
+		 * rest of the page can be read and the commit page is off
+		 * the reader page.
+		 */
+		if (full &&
+		    (!read || (len < (commit - read)) ||
+		     cpu_buffer->reader_page == cpu_buffer->commit_page))
+			goto out_unlock;
+
+		if (len > (commit - read))
+			len = (commit - read);
+
+		/* Always keep the time extend and data together */
+		size = rb_event_ts_length(event);
+
+		if (len < size)
+			goto out_unlock;
+
+		/* save the current timestamp, since the user will need it */
+		save_timestamp = cpu_buffer->read_stamp;
+
+		/* Need to copy one event at a time */
+		do {
+			/* We need the size of one event, because
+			 * rb_advance_reader only advances by one event,
+			 * whereas rb_event_ts_length may include the size of
+			 * one or two events.
+			 * We have already ensured there's enough space if this
+			 * is a time extend. */
+			size = rb_event_length(event);
+			memcpy(bpage->data + pos, rpage->data + rpos, size);
+
+			len -= size;
+
+			rb_advance_reader(cpu_buffer);
+			rpos = reader->read;
+			pos += size;
+
+			if (rpos >= commit)
+				break;
+
+			event = rb_reader_event(cpu_buffer);
+			/* Always keep the time extend and data together */
+			size = rb_event_ts_length(event);
+		} while (len >= size);
+
+		/* update bpage */
+		local_set(&bpage->commit, pos);
+		bpage->time_stamp = save_timestamp;
+
+		/* we copied everything to the beginning */
+		read = 0;
+	} else {
+		/* update the entry counter */
+		cpu_buffer->read += rb_page_entries(reader);
+		cpu_buffer->read_bytes += rb_page_commit(reader);
+
+		/* swap the pages */
+		rb_init_page(bpage);
+		bpage = reader->page;
+		reader->page = *data_page;
+		local_set(&reader->write, 0);
+		local_set(&reader->entries, 0);
+		reader->read = 0;
+		*data_page = bpage;
+
+		/*
+		 * Use the real_end for the data size,
+		 * This gives us a chance to store the lost events
+		 * on the page.
+		 */
+		if (reader->real_end)
+			local_set(&bpage->commit, reader->real_end);
+	}
+	ret = read;
+
+	cpu_buffer->lost_events = 0;
+
+	commit = local_read(&bpage->commit);
+	/*
+	 * Set a flag in the commit field if we lost events
+	 */
+	if (missed_events) {
+		/* If there is room at the end of the page to save the
+		 * missed events, then record it there.
+		 */
+		if (BUF_PAGE_SIZE - commit >= sizeof(missed_events)) {
+			memcpy(&bpage->data[commit], &missed_events,
+			       sizeof(missed_events));
+			local_add(RB_MISSED_STORED, &bpage->commit);
+			commit += sizeof(missed_events);
+		}
+		local_add(RB_MISSED_EVENTS, &bpage->commit);
+	}
+
+	/*
+	 * This page may be off to user land. Zero it out here.
+	 */
+	if (commit < BUF_PAGE_SIZE)
+		memset(&bpage->data[commit], 0, BUF_PAGE_SIZE - commit);
+
+ out_unlock:
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+ out:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_read_page);
+
+/*
+ * We only allocate new buffers, never free them if the CPU goes down.
+ * If we were to free the buffer, then the user would lose any trace that was in
+ * the buffer.
+ */
+int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node)
+{
+	struct trace_buffer *buffer;
+	long nr_pages_same;
+	int cpu_i;
+	unsigned long nr_pages;
+
+	buffer = container_of(node, struct trace_buffer, node);
+	if (cpumask_test_cpu(cpu, buffer->cpumask))
+		return 0;
+
+	nr_pages = 0;
+	nr_pages_same = 1;
+	/* check if all cpu sizes are same */
+	for_each_buffer_cpu(buffer, cpu_i) {
+		/* fill in the size from first enabled cpu */
+		if (nr_pages == 0)
+			nr_pages = buffer->buffers[cpu_i]->nr_pages;
+		if (nr_pages != buffer->buffers[cpu_i]->nr_pages) {
+			nr_pages_same = 0;
+			break;
+		}
+	}
+	/* allocate minimum pages, user can later expand it */
+	if (!nr_pages_same)
+		nr_pages = 2;
+	buffer->buffers[cpu] =
+		rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
+	if (!buffer->buffers[cpu]) {
+		WARN(1, "failed to allocate ring buffer on CPU %u\n",
+		     cpu);
+		return -ENOMEM;
+	}
+	smp_wmb();
+	cpumask_set_cpu(cpu, buffer->cpumask);
+	return 0;
+}
+
+#ifdef CONFIG_RING_BUFFER_STARTUP_TEST
+/*
+ * This is a basic integrity check of the ring buffer.
+ * Late in the boot cycle this test will run when configured in.
+ * It will kick off a thread per CPU that will go into a loop
+ * writing to the per cpu ring buffer various sizes of data.
+ * Some of the data will be large items, some small.
+ *
+ * Another thread is created that goes into a spin, sending out
+ * IPIs to the other CPUs to also write into the ring buffer.
+ * this is to test the nesting ability of the buffer.
+ *
+ * Basic stats are recorded and reported. If something in the
+ * ring buffer should happen that's not expected, a big warning
+ * is displayed and all ring buffers are disabled.
+ */
+static struct task_struct *rb_threads[NR_CPUS] __initdata;
+
+struct rb_test_data {
+	struct trace_buffer *buffer;
+	unsigned long		events;
+	unsigned long		bytes_written;
+	unsigned long		bytes_alloc;
+	unsigned long		bytes_dropped;
+	unsigned long		events_nested;
+	unsigned long		bytes_written_nested;
+	unsigned long		bytes_alloc_nested;
+	unsigned long		bytes_dropped_nested;
+	int			min_size_nested;
+	int			max_size_nested;
+	int			max_size;
+	int			min_size;
+	int			cpu;
+	int			cnt;
+};
+
+static struct rb_test_data rb_data[NR_CPUS] __initdata;
+
+/* 1 meg per cpu */
+#define RB_TEST_BUFFER_SIZE	1048576
+
+static char rb_string[] __initdata =
+	"abcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*()?+\\"
+	"?+|:';\",.<>/?abcdefghijklmnopqrstuvwxyz1234567890"
+	"!@#$%^&*()?+\\?+|:';\",.<>/?abcdefghijklmnopqrstuv";
+
+static bool rb_test_started __initdata;
+
+struct rb_item {
+	int size;
+	char str[];
+};
+
+static __init int rb_write_something(struct rb_test_data *data, bool nested)
+{
+	struct ring_buffer_event *event;
+	struct rb_item *item;
+	bool started;
+	int event_len;
+	int size;
+	int len;
+	int cnt;
+
+	/* Have nested writes different that what is written */
+	cnt = data->cnt + (nested ? 27 : 0);
+
+	/* Multiply cnt by ~e, to make some unique increment */
+	size = (cnt * 68 / 25) % (sizeof(rb_string) - 1);
+
+	len = size + sizeof(struct rb_item);
+
+	started = rb_test_started;
+	/* read rb_test_started before checking buffer enabled */
+	smp_rmb();
+
+	event = ring_buffer_lock_reserve(data->buffer, len);
+	if (!event) {
+		/* Ignore dropped events before test starts. */
+		if (started) {
+			if (nested)
+				data->bytes_dropped += len;
+			else
+				data->bytes_dropped_nested += len;
+		}
+		return len;
+	}
+
+	event_len = ring_buffer_event_length(event);
+
+	if (RB_WARN_ON(data->buffer, event_len < len))
+		goto out;
+
+	item = ring_buffer_event_data(event);
+	item->size = size;
+	memcpy(item->str, rb_string, size);
+
+	if (nested) {
+		data->bytes_alloc_nested += event_len;
+		data->bytes_written_nested += len;
+		data->events_nested++;
+		if (!data->min_size_nested || len < data->min_size_nested)
+			data->min_size_nested = len;
+		if (len > data->max_size_nested)
+			data->max_size_nested = len;
+	} else {
+		data->bytes_alloc += event_len;
+		data->bytes_written += len;
+		data->events++;
+		if (!data->min_size || len < data->min_size)
+			data->max_size = len;
+		if (len > data->max_size)
+			data->max_size = len;
+	}
+
+ out:
+	ring_buffer_unlock_commit(data->buffer, event);
+
+	return 0;
+}
+
+static __init int rb_test(void *arg)
+{
+	struct rb_test_data *data = arg;
+
+	while (!kthread_should_stop()) {
+		rb_write_something(data, false);
+		data->cnt++;
+
+		set_current_state(TASK_INTERRUPTIBLE);
+		/* Now sleep between a min of 100-300us and a max of 1ms */
+		usleep_range(((data->cnt % 3) + 1) * 100, 1000);
+	}
+
+	return 0;
+}
+
+static __init void rb_ipi(void *ignore)
+{
+	struct rb_test_data *data;
+	int cpu = smp_processor_id();
+
+	data = &rb_data[cpu];
+	rb_write_something(data, true);
+}
+
+static __init int rb_hammer_test(void *arg)
+{
+	while (!kthread_should_stop()) {
+
+		/* Send an IPI to all cpus to write data! */
+		smp_call_function(rb_ipi, NULL, 1);
+		/* No sleep, but for non preempt, let others run */
+		schedule();
+	}
+
+	return 0;
+}
+
+static __init int test_ringbuffer(void)
+{
+	struct task_struct *rb_hammer;
+	struct trace_buffer *buffer;
+	int cpu;
+	int ret = 0;
+
+	if (security_locked_down(LOCKDOWN_TRACEFS)) {
+		pr_warn("Lockdown is enabled, skipping ring buffer tests\n");
+		return 0;
+	}
+
+	pr_info("Running ring buffer tests...\n");
+
+	buffer = ring_buffer_alloc(RB_TEST_BUFFER_SIZE, RB_FL_OVERWRITE);
+	if (WARN_ON(!buffer))
+		return 0;
+
+	/* Disable buffer so that threads can't write to it yet */
+	ring_buffer_record_off(buffer);
+
+	for_each_online_cpu(cpu) {
+		rb_data[cpu].buffer = buffer;
+		rb_data[cpu].cpu = cpu;
+		rb_data[cpu].cnt = cpu;
+		rb_threads[cpu] = kthread_run_on_cpu(rb_test, &rb_data[cpu],
+						     cpu, "rbtester/%u");
+		if (WARN_ON(IS_ERR(rb_threads[cpu]))) {
+			pr_cont("FAILED\n");
+			ret = PTR_ERR(rb_threads[cpu]);
+			goto out_free;
+		}
+	}
+
+	/* Now create the rb hammer! */
+	rb_hammer = kthread_run(rb_hammer_test, NULL, "rbhammer");
+	if (WARN_ON(IS_ERR(rb_hammer))) {
+		pr_cont("FAILED\n");
+		ret = PTR_ERR(rb_hammer);
+		goto out_free;
+	}
+
+	ring_buffer_record_on(buffer);
+	/*
+	 * Show buffer is enabled before setting rb_test_started.
+	 * Yes there's a small race window where events could be
+	 * dropped and the thread wont catch it. But when a ring
+	 * buffer gets enabled, there will always be some kind of
+	 * delay before other CPUs see it. Thus, we don't care about
+	 * those dropped events. We care about events dropped after
+	 * the threads see that the buffer is active.
+	 */
+	smp_wmb();
+	rb_test_started = true;
+
+	set_current_state(TASK_INTERRUPTIBLE);
+	/* Just run for 10 seconds */;
+	schedule_timeout(10 * HZ);
+
+	kthread_stop(rb_hammer);
+
+ out_free:
+	for_each_online_cpu(cpu) {
+		if (!rb_threads[cpu])
+			break;
+		kthread_stop(rb_threads[cpu]);
+	}
+	if (ret) {
+		ring_buffer_free(buffer);
+		return ret;
+	}
+
+	/* Report! */
+	pr_info("finished\n");
+	for_each_online_cpu(cpu) {
+		struct ring_buffer_event *event;
+		struct rb_test_data *data = &rb_data[cpu];
+		struct rb_item *item;
+		unsigned long total_events;
+		unsigned long total_dropped;
+		unsigned long total_written;
+		unsigned long total_alloc;
+		unsigned long total_read = 0;
+		unsigned long total_size = 0;
+		unsigned long total_len = 0;
+		unsigned long total_lost = 0;
+		unsigned long lost;
+		int big_event_size;
+		int small_event_size;
+
+		ret = -1;
+
+		total_events = data->events + data->events_nested;
+		total_written = data->bytes_written + data->bytes_written_nested;
+		total_alloc = data->bytes_alloc + data->bytes_alloc_nested;
+		total_dropped = data->bytes_dropped + data->bytes_dropped_nested;
+
+		big_event_size = data->max_size + data->max_size_nested;
+		small_event_size = data->min_size + data->min_size_nested;
+
+		pr_info("CPU %d:\n", cpu);
+		pr_info("              events:    %ld\n", total_events);
+		pr_info("       dropped bytes:    %ld\n", total_dropped);
+		pr_info("       alloced bytes:    %ld\n", total_alloc);
+		pr_info("       written bytes:    %ld\n", total_written);
+		pr_info("       biggest event:    %d\n", big_event_size);
+		pr_info("      smallest event:    %d\n", small_event_size);
+
+		if (RB_WARN_ON(buffer, total_dropped))
+			break;
+
+		ret = 0;
+
+		while ((event = ring_buffer_consume(buffer, cpu, NULL, &lost))) {
+			total_lost += lost;
+			item = ring_buffer_event_data(event);
+			total_len += ring_buffer_event_length(event);
+			total_size += item->size + sizeof(struct rb_item);
+			if (memcmp(&item->str[0], rb_string, item->size) != 0) {
+				pr_info("FAILED!\n");
+				pr_info("buffer had: %.*s\n", item->size, item->str);
+				pr_info("expected:   %.*s\n", item->size, rb_string);
+				RB_WARN_ON(buffer, 1);
+				ret = -1;
+				break;
+			}
+			total_read++;
+		}
+		if (ret)
+			break;
+
+		ret = -1;
+
+		pr_info("         read events:   %ld\n", total_read);
+		pr_info("         lost events:   %ld\n", total_lost);
+		pr_info("        total events:   %ld\n", total_lost + total_read);
+		pr_info("  recorded len bytes:   %ld\n", total_len);
+		pr_info(" recorded size bytes:   %ld\n", total_size);
+		if (total_lost) {
+			pr_info(" With dropped events, record len and size may not match\n"
+				" alloced and written from above\n");
+		} else {
+			if (RB_WARN_ON(buffer, total_len != total_alloc ||
+				       total_size != total_written))
+				break;
+		}
+		if (RB_WARN_ON(buffer, total_lost + total_read != total_events))
+			break;
+
+		ret = 0;
+	}
+	if (!ret)
+		pr_info("Ring buffer PASSED!\n");
+
+	ring_buffer_free(buffer);
+	return 0;
+}
+
+late_initcall(test_ringbuffer);
+#endif /* CONFIG_RING_BUFFER_STARTUP_TEST */
diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
new file mode 100644
index 000000000..78e576575
--- /dev/null
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -0,0 +1,497 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ring buffer tester and benchmark
+ *
+ * Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
+ */
+#include <linux/ring_buffer.h>
+#include <linux/completion.h>
+#include <linux/kthread.h>
+#include <uapi/linux/sched/types.h>
+#include <linux/module.h>
+#include <linux/ktime.h>
+#include <asm/local.h>
+
+struct rb_page {
+	u64		ts;
+	local_t		commit;
+	char		data[4080];
+};
+
+/* run time and sleep time in seconds */
+#define RUN_TIME	10ULL
+#define SLEEP_TIME	10
+
+/* number of events for writer to wake up the reader */
+static int wakeup_interval = 100;
+
+static int reader_finish;
+static DECLARE_COMPLETION(read_start);
+static DECLARE_COMPLETION(read_done);
+
+static struct trace_buffer *buffer;
+static struct task_struct *producer;
+static struct task_struct *consumer;
+static unsigned long read;
+
+static unsigned int disable_reader;
+module_param(disable_reader, uint, 0644);
+MODULE_PARM_DESC(disable_reader, "only run producer");
+
+static unsigned int write_iteration = 50;
+module_param(write_iteration, uint, 0644);
+MODULE_PARM_DESC(write_iteration, "# of writes between timestamp readings");
+
+static int producer_nice = MAX_NICE;
+static int consumer_nice = MAX_NICE;
+
+static int producer_fifo;
+static int consumer_fifo;
+
+module_param(producer_nice, int, 0644);
+MODULE_PARM_DESC(producer_nice, "nice prio for producer");
+
+module_param(consumer_nice, int, 0644);
+MODULE_PARM_DESC(consumer_nice, "nice prio for consumer");
+
+module_param(producer_fifo, int, 0644);
+MODULE_PARM_DESC(producer_fifo, "use fifo for producer: 0 - disabled, 1 - low prio, 2 - fifo");
+
+module_param(consumer_fifo, int, 0644);
+MODULE_PARM_DESC(consumer_fifo, "use fifo for consumer: 0 - disabled, 1 - low prio, 2 - fifo");
+
+static int read_events;
+
+static int test_error;
+
+#define TEST_ERROR()				\
+	do {					\
+		if (!test_error) {		\
+			test_error = 1;		\
+			WARN_ON(1);		\
+		}				\
+	} while (0)
+
+enum event_status {
+	EVENT_FOUND,
+	EVENT_DROPPED,
+};
+
+static bool break_test(void)
+{
+	return test_error || kthread_should_stop();
+}
+
+static enum event_status read_event(int cpu)
+{
+	struct ring_buffer_event *event;
+	int *entry;
+	u64 ts;
+
+	event = ring_buffer_consume(buffer, cpu, &ts, NULL);
+	if (!event)
+		return EVENT_DROPPED;
+
+	entry = ring_buffer_event_data(event);
+	if (*entry != cpu) {
+		TEST_ERROR();
+		return EVENT_DROPPED;
+	}
+
+	read++;
+	return EVENT_FOUND;
+}
+
+static enum event_status read_page(int cpu)
+{
+	struct ring_buffer_event *event;
+	struct rb_page *rpage;
+	unsigned long commit;
+	void *bpage;
+	int *entry;
+	int ret;
+	int inc;
+	int i;
+
+	bpage = ring_buffer_alloc_read_page(buffer, cpu);
+	if (IS_ERR(bpage))
+		return EVENT_DROPPED;
+
+	ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1);
+	if (ret >= 0) {
+		rpage = bpage;
+		/* The commit may have missed event flags set, clear them */
+		commit = local_read(&rpage->commit) & 0xfffff;
+		for (i = 0; i < commit && !test_error ; i += inc) {
+
+			if (i >= (PAGE_SIZE - offsetof(struct rb_page, data))) {
+				TEST_ERROR();
+				break;
+			}
+
+			inc = -1;
+			event = (void *)&rpage->data[i];
+			switch (event->type_len) {
+			case RINGBUF_TYPE_PADDING:
+				/* failed writes may be discarded events */
+				if (!event->time_delta)
+					TEST_ERROR();
+				inc = event->array[0] + 4;
+				break;
+			case RINGBUF_TYPE_TIME_EXTEND:
+				inc = 8;
+				break;
+			case 0:
+				entry = ring_buffer_event_data(event);
+				if (*entry != cpu) {
+					TEST_ERROR();
+					break;
+				}
+				read++;
+				if (!event->array[0]) {
+					TEST_ERROR();
+					break;
+				}
+				inc = event->array[0] + 4;
+				break;
+			default:
+				entry = ring_buffer_event_data(event);
+				if (*entry != cpu) {
+					TEST_ERROR();
+					break;
+				}
+				read++;
+				inc = ((event->type_len + 1) * 4);
+			}
+			if (test_error)
+				break;
+
+			if (inc <= 0) {
+				TEST_ERROR();
+				break;
+			}
+		}
+	}
+	ring_buffer_free_read_page(buffer, cpu, bpage);
+
+	if (ret < 0)
+		return EVENT_DROPPED;
+	return EVENT_FOUND;
+}
+
+static void ring_buffer_consumer(void)
+{
+	/* toggle between reading pages and events */
+	read_events ^= 1;
+
+	read = 0;
+	/*
+	 * Continue running until the producer specifically asks to stop
+	 * and is ready for the completion.
+	 */
+	while (!READ_ONCE(reader_finish)) {
+		int found = 1;
+
+		while (found && !test_error) {
+			int cpu;
+
+			found = 0;
+			for_each_online_cpu(cpu) {
+				enum event_status stat;
+
+				if (read_events)
+					stat = read_event(cpu);
+				else
+					stat = read_page(cpu);
+
+				if (test_error)
+					break;
+
+				if (stat == EVENT_FOUND)
+					found = 1;
+
+			}
+		}
+
+		/* Wait till the producer wakes us up when there is more data
+		 * available or when the producer wants us to finish reading.
+		 */
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (reader_finish)
+			break;
+
+		schedule();
+	}
+	__set_current_state(TASK_RUNNING);
+	reader_finish = 0;
+	complete(&read_done);
+}
+
+static void ring_buffer_producer(void)
+{
+	ktime_t start_time, end_time, timeout;
+	unsigned long long time;
+	unsigned long long entries;
+	unsigned long long overruns;
+	unsigned long missed = 0;
+	unsigned long hit = 0;
+	unsigned long avg;
+	int cnt = 0;
+
+	/*
+	 * Hammer the buffer for 10 secs (this may
+	 * make the system stall)
+	 */
+	trace_printk("Starting ring buffer hammer\n");
+	start_time = ktime_get();
+	timeout = ktime_add_ns(start_time, RUN_TIME * NSEC_PER_SEC);
+	do {
+		struct ring_buffer_event *event;
+		int *entry;
+		int i;
+
+		for (i = 0; i < write_iteration; i++) {
+			event = ring_buffer_lock_reserve(buffer, 10);
+			if (!event) {
+				missed++;
+			} else {
+				hit++;
+				entry = ring_buffer_event_data(event);
+				*entry = smp_processor_id();
+				ring_buffer_unlock_commit(buffer, event);
+			}
+		}
+		end_time = ktime_get();
+
+		cnt++;
+		if (consumer && !(cnt % wakeup_interval))
+			wake_up_process(consumer);
+
+#ifndef CONFIG_PREEMPTION
+		/*
+		 * If we are a non preempt kernel, the 10 seconds run will
+		 * stop everything while it runs. Instead, we will call
+		 * cond_resched and also add any time that was lost by a
+		 * reschedule.
+		 *
+		 * Do a cond resched at the same frequency we would wake up
+		 * the reader.
+		 */
+		if (cnt % wakeup_interval)
+			cond_resched();
+#endif
+	} while (ktime_before(end_time, timeout) && !break_test());
+	trace_printk("End ring buffer hammer\n");
+
+	if (consumer) {
+		/* Init both completions here to avoid races */
+		init_completion(&read_start);
+		init_completion(&read_done);
+		/* the completions must be visible before the finish var */
+		smp_wmb();
+		reader_finish = 1;
+		wake_up_process(consumer);
+		wait_for_completion(&read_done);
+	}
+
+	time = ktime_us_delta(end_time, start_time);
+
+	entries = ring_buffer_entries(buffer);
+	overruns = ring_buffer_overruns(buffer);
+
+	if (test_error)
+		trace_printk("ERROR!\n");
+
+	if (!disable_reader) {
+		if (consumer_fifo)
+			trace_printk("Running Consumer at SCHED_FIFO %s\n",
+				     consumer_fifo == 1 ? "low" : "high");
+		else
+			trace_printk("Running Consumer at nice: %d\n",
+				     consumer_nice);
+	}
+	if (producer_fifo)
+		trace_printk("Running Producer at SCHED_FIFO %s\n",
+			     producer_fifo == 1 ? "low" : "high");
+	else
+		trace_printk("Running Producer at nice: %d\n",
+			     producer_nice);
+
+	/* Let the user know that the test is running at low priority */
+	if (!producer_fifo && !consumer_fifo &&
+	    producer_nice == MAX_NICE && consumer_nice == MAX_NICE)
+		trace_printk("WARNING!!! This test is running at lowest priority.\n");
+
+	trace_printk("Time:     %lld (usecs)\n", time);
+	trace_printk("Overruns: %lld\n", overruns);
+	if (disable_reader)
+		trace_printk("Read:     (reader disabled)\n");
+	else
+		trace_printk("Read:     %ld  (by %s)\n", read,
+			read_events ? "events" : "pages");
+	trace_printk("Entries:  %lld\n", entries);
+	trace_printk("Total:    %lld\n", entries + overruns + read);
+	trace_printk("Missed:   %ld\n", missed);
+	trace_printk("Hit:      %ld\n", hit);
+
+	/* Convert time from usecs to millisecs */
+	do_div(time, USEC_PER_MSEC);
+	if (time)
+		hit /= (long)time;
+	else
+		trace_printk("TIME IS ZERO??\n");
+
+	trace_printk("Entries per millisec: %ld\n", hit);
+
+	if (hit) {
+		/* Calculate the average time in nanosecs */
+		avg = NSEC_PER_MSEC / hit;
+		trace_printk("%ld ns per entry\n", avg);
+	}
+
+	if (missed) {
+		if (time)
+			missed /= (long)time;
+
+		trace_printk("Total iterations per millisec: %ld\n",
+			     hit + missed);
+
+		/* it is possible that hit + missed will overflow and be zero */
+		if (!(hit + missed)) {
+			trace_printk("hit + missed overflowed and totalled zero!\n");
+			hit--; /* make it non zero */
+		}
+
+		/* Calculate the average time in nanosecs */
+		avg = NSEC_PER_MSEC / (hit + missed);
+		trace_printk("%ld ns per entry\n", avg);
+	}
+}
+
+static void wait_to_die(void)
+{
+	set_current_state(TASK_INTERRUPTIBLE);
+	while (!kthread_should_stop()) {
+		schedule();
+		set_current_state(TASK_INTERRUPTIBLE);
+	}
+	__set_current_state(TASK_RUNNING);
+}
+
+static int ring_buffer_consumer_thread(void *arg)
+{
+	while (!break_test()) {
+		complete(&read_start);
+
+		ring_buffer_consumer();
+
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (break_test())
+			break;
+		schedule();
+	}
+	__set_current_state(TASK_RUNNING);
+
+	if (!kthread_should_stop())
+		wait_to_die();
+
+	return 0;
+}
+
+static int ring_buffer_producer_thread(void *arg)
+{
+	while (!break_test()) {
+		ring_buffer_reset(buffer);
+
+		if (consumer) {
+			wake_up_process(consumer);
+			wait_for_completion(&read_start);
+		}
+
+		ring_buffer_producer();
+		if (break_test())
+			goto out_kill;
+
+		trace_printk("Sleeping for 10 secs\n");
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (break_test())
+			goto out_kill;
+		schedule_timeout(HZ * SLEEP_TIME);
+	}
+
+out_kill:
+	__set_current_state(TASK_RUNNING);
+	if (!kthread_should_stop())
+		wait_to_die();
+
+	return 0;
+}
+
+static int __init ring_buffer_benchmark_init(void)
+{
+	int ret;
+
+	/* make a one meg buffer in overwite mode */
+	buffer = ring_buffer_alloc(1000000, RB_FL_OVERWRITE);
+	if (!buffer)
+		return -ENOMEM;
+
+	if (!disable_reader) {
+		consumer = kthread_create(ring_buffer_consumer_thread,
+					  NULL, "rb_consumer");
+		ret = PTR_ERR(consumer);
+		if (IS_ERR(consumer))
+			goto out_fail;
+	}
+
+	producer = kthread_run(ring_buffer_producer_thread,
+			       NULL, "rb_producer");
+	ret = PTR_ERR(producer);
+
+	if (IS_ERR(producer))
+		goto out_kill;
+
+	/*
+	 * Run them as low-prio background tasks by default:
+	 */
+	if (!disable_reader) {
+		if (consumer_fifo >= 2)
+			sched_set_fifo(consumer);
+		else if (consumer_fifo == 1)
+			sched_set_fifo_low(consumer);
+		else
+			set_user_nice(consumer, consumer_nice);
+	}
+
+	if (producer_fifo >= 2)
+		sched_set_fifo(producer);
+	else if (producer_fifo == 1)
+		sched_set_fifo_low(producer);
+	else
+		set_user_nice(producer, producer_nice);
+
+	return 0;
+
+ out_kill:
+	if (consumer)
+		kthread_stop(consumer);
+
+ out_fail:
+	ring_buffer_free(buffer);
+	return ret;
+}
+
+static void __exit ring_buffer_benchmark_exit(void)
+{
+	kthread_stop(producer);
+	if (consumer)
+		kthread_stop(consumer);
+	ring_buffer_free(buffer);
+}
+
+module_init(ring_buffer_benchmark_init);
+module_exit(ring_buffer_benchmark_exit);
+
+MODULE_AUTHOR("Steven Rostedt");
+MODULE_DESCRIPTION("ring_buffer_benchmark");
+MODULE_LICENSE("GPL");
diff --git a/kernel/trace/rpm-traces.c b/kernel/trace/rpm-traces.c
new file mode 100644
index 000000000..25dec0b00
--- /dev/null
+++ b/kernel/trace/rpm-traces.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Power trace points
+ *
+ * Copyright (C) 2009 Ming Lei <ming.lei@canonical.com>
+ */
+
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/rpm.h>
+
+EXPORT_TRACEPOINT_SYMBOL_GPL(rpm_return_int);
+EXPORT_TRACEPOINT_SYMBOL_GPL(rpm_idle);
+EXPORT_TRACEPOINT_SYMBOL_GPL(rpm_suspend);
+EXPORT_TRACEPOINT_SYMBOL_GPL(rpm_resume);
diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
new file mode 100644
index 000000000..831779607
--- /dev/null
+++ b/kernel/trace/rv/Kconfig
@@ -0,0 +1,78 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+config DA_MON_EVENTS
+	bool
+
+config DA_MON_EVENTS_IMPLICIT
+	select DA_MON_EVENTS
+	bool
+
+config DA_MON_EVENTS_ID
+	select DA_MON_EVENTS
+	bool
+
+menuconfig RV
+	bool "Runtime Verification"
+	depends on TRACING
+	help
+	  Enable the kernel runtime verification infrastructure. RV is a
+	  lightweight (yet rigorous) method that complements classical
+	  exhaustive verification techniques (such as model checking and
+	  theorem proving). RV works by analyzing the trace of the system's
+	  actual execution, comparing it against a formal specification of
+	  the system behavior.
+
+	  For further information, see:
+	    Documentation/trace/rv/runtime-verification.rst
+
+config RV_MON_WIP
+	depends on RV
+	depends on PREEMPT_TRACER
+	select DA_MON_EVENTS_IMPLICIT
+	bool "wip monitor"
+	help
+	  Enable wip (wakeup in preemptive) sample monitor that illustrates
+	  the usage of per-cpu monitors, and one limitation of the
+	  preempt_disable/enable events.
+
+	  For further information, see:
+	    Documentation/trace/rv/monitor_wip.rst
+
+config RV_MON_WWNR
+	depends on RV
+	select DA_MON_EVENTS_ID
+	bool "wwnr monitor"
+	help
+	  Enable wwnr (wakeup while not running) sample monitor, this is a
+	  sample monitor that illustrates the usage of per-task monitor.
+	  The model is borken on purpose: it serves to test reactors.
+
+	  For further information, see:
+	    Documentation/trace/rv/monitor_wwnr.rst
+
+config RV_REACTORS
+	bool "Runtime verification reactors"
+	default y
+	depends on RV
+	help
+	  Enables the online runtime verification reactors. A runtime
+	  monitor can cause a reaction to the detection of an exception
+	  on the model's execution. By default, the monitors have
+	  tracing reactions, printing the monitor output via tracepoints,
+	  but other reactions can be added (on-demand) via this interface.
+
+config RV_REACT_PRINTK
+	bool "Printk reactor"
+	depends on RV_REACTORS
+	default y
+	help
+	  Enables the printk reactor. The printk reactor emits a printk()
+	  message if an exception is found.
+
+config RV_REACT_PANIC
+	bool "Panic reactor"
+	depends on RV_REACTORS
+	default y
+	help
+	  Enables the panic reactor. The panic reactor emits a printk()
+	  message if an exception is found and panic()s the system.
diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile
new file mode 100644
index 000000000..963d14875
--- /dev/null
+++ b/kernel/trace/rv/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_RV) += rv.o
+obj-$(CONFIG_RV_MON_WIP) += monitors/wip/wip.o
+obj-$(CONFIG_RV_MON_WWNR) += monitors/wwnr/wwnr.o
+obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
+obj-$(CONFIG_RV_REACT_PRINTK) += reactor_printk.o
+obj-$(CONFIG_RV_REACT_PANIC) += reactor_panic.o
diff --git a/kernel/trace/rv/monitors/wip/wip.c b/kernel/trace/rv/monitors/wip/wip.c
new file mode 100644
index 000000000..b2b49a27e
--- /dev/null
+++ b/kernel/trace/rv/monitors/wip/wip.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+#include <rv/instrumentation.h>
+#include <rv/da_monitor.h>
+
+#define MODULE_NAME "wip"
+
+#include <trace/events/rv.h>
+#include <trace/events/sched.h>
+#include <trace/events/preemptirq.h>
+
+#include "wip.h"
+
+static struct rv_monitor rv_wip;
+DECLARE_DA_MON_PER_CPU(wip, unsigned char);
+
+static void handle_preempt_disable(void *data, unsigned long ip, unsigned long parent_ip)
+{
+	da_handle_event_wip(preempt_disable_wip);
+}
+
+static void handle_preempt_enable(void *data, unsigned long ip, unsigned long parent_ip)
+{
+	da_handle_start_event_wip(preempt_enable_wip);
+}
+
+static void handle_sched_waking(void *data, struct task_struct *task)
+{
+	da_handle_event_wip(sched_waking_wip);
+}
+
+static int enable_wip(void)
+{
+	int retval;
+
+	retval = da_monitor_init_wip();
+	if (retval)
+		return retval;
+
+	rv_attach_trace_probe("wip", preempt_enable, handle_preempt_enable);
+	rv_attach_trace_probe("wip", sched_waking, handle_sched_waking);
+	rv_attach_trace_probe("wip", preempt_disable, handle_preempt_disable);
+
+	return 0;
+}
+
+static void disable_wip(void)
+{
+	rv_wip.enabled = 0;
+
+	rv_detach_trace_probe("wip", preempt_disable, handle_preempt_disable);
+	rv_detach_trace_probe("wip", preempt_enable, handle_preempt_enable);
+	rv_detach_trace_probe("wip", sched_waking, handle_sched_waking);
+
+	da_monitor_destroy_wip();
+}
+
+static struct rv_monitor rv_wip = {
+	.name = "wip",
+	.description = "wakeup in preemptive per-cpu testing monitor.",
+	.enable = enable_wip,
+	.disable = disable_wip,
+	.reset = da_monitor_reset_all_wip,
+	.enabled = 0,
+};
+
+static int __init register_wip(void)
+{
+	rv_register_monitor(&rv_wip);
+	return 0;
+}
+
+static void __exit unregister_wip(void)
+{
+	rv_unregister_monitor(&rv_wip);
+}
+
+module_init(register_wip);
+module_exit(unregister_wip);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Daniel Bristot de Oliveira <bristot@kernel.org>");
+MODULE_DESCRIPTION("wip: wakeup in preemptive - per-cpu sample monitor.");
diff --git a/kernel/trace/rv/monitors/wip/wip.h b/kernel/trace/rv/monitors/wip/wip.h
new file mode 100644
index 000000000..dacc37b62
--- /dev/null
+++ b/kernel/trace/rv/monitors/wip/wip.h
@@ -0,0 +1,46 @@
+/*
+ * Automatically generated C representation of wip automaton
+ * For further information about this format, see kernel documentation:
+ *   Documentation/trace/rv/deterministic_automata.rst
+ */
+
+enum states_wip {
+	preemptive_wip = 0,
+	non_preemptive_wip,
+	state_max_wip
+};
+
+#define INVALID_STATE state_max_wip
+
+enum events_wip {
+	preempt_disable_wip = 0,
+	preempt_enable_wip,
+	sched_waking_wip,
+	event_max_wip
+};
+
+struct automaton_wip {
+	char *state_names[state_max_wip];
+	char *event_names[event_max_wip];
+	unsigned char function[state_max_wip][event_max_wip];
+	unsigned char initial_state;
+	bool final_states[state_max_wip];
+};
+
+static struct automaton_wip automaton_wip = {
+	.state_names = {
+		"preemptive",
+		"non_preemptive"
+	},
+	.event_names = {
+		"preempt_disable",
+		"preempt_enable",
+		"sched_waking"
+	},
+	.function = {
+		{ non_preemptive_wip,      INVALID_STATE,      INVALID_STATE },
+		{      INVALID_STATE,     preemptive_wip, non_preemptive_wip },
+	},
+	.initial_state = preemptive_wip,
+	.final_states = { 1, 0 },
+};
diff --git a/kernel/trace/rv/monitors/wwnr/wwnr.c b/kernel/trace/rv/monitors/wwnr/wwnr.c
new file mode 100644
index 000000000..0e43dd2db
--- /dev/null
+++ b/kernel/trace/rv/monitors/wwnr/wwnr.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+#include <rv/instrumentation.h>
+#include <rv/da_monitor.h>
+
+#define MODULE_NAME "wwnr"
+
+#include <trace/events/rv.h>
+#include <trace/events/sched.h>
+
+#include "wwnr.h"
+
+static struct rv_monitor rv_wwnr;
+DECLARE_DA_MON_PER_TASK(wwnr, unsigned char);
+
+static void handle_switch(void *data, bool preempt, struct task_struct *p,
+			  struct task_struct *n, unsigned int prev_state)
+{
+	/* start monitoring only after the first suspension */
+	if (prev_state == TASK_INTERRUPTIBLE)
+		da_handle_start_event_wwnr(p, switch_out_wwnr);
+	else
+		da_handle_event_wwnr(p, switch_out_wwnr);
+
+	da_handle_event_wwnr(n, switch_in_wwnr);
+}
+
+static void handle_wakeup(void *data, struct task_struct *p)
+{
+	da_handle_event_wwnr(p, wakeup_wwnr);
+}
+
+static int enable_wwnr(void)
+{
+	int retval;
+
+	retval = da_monitor_init_wwnr();
+	if (retval)
+		return retval;
+
+	rv_attach_trace_probe("wwnr", sched_switch, handle_switch);
+	rv_attach_trace_probe("wwnr", sched_wakeup, handle_wakeup);
+
+	return 0;
+}
+
+static void disable_wwnr(void)
+{
+	rv_wwnr.enabled = 0;
+
+	rv_detach_trace_probe("wwnr", sched_switch, handle_switch);
+	rv_detach_trace_probe("wwnr", sched_wakeup, handle_wakeup);
+
+	da_monitor_destroy_wwnr();
+}
+
+static struct rv_monitor rv_wwnr = {
+	.name = "wwnr",
+	.description = "wakeup while not running per-task testing model.",
+	.enable = enable_wwnr,
+	.disable = disable_wwnr,
+	.reset = da_monitor_reset_all_wwnr,
+	.enabled = 0,
+};
+
+static int __init register_wwnr(void)
+{
+	rv_register_monitor(&rv_wwnr);
+	return 0;
+}
+
+static void __exit unregister_wwnr(void)
+{
+	rv_unregister_monitor(&rv_wwnr);
+}
+
+module_init(register_wwnr);
+module_exit(unregister_wwnr);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Daniel Bristot de Oliveira <bristot@kernel.org>");
+MODULE_DESCRIPTION("wwnr: wakeup while not running monitor");
diff --git a/kernel/trace/rv/monitors/wwnr/wwnr.h b/kernel/trace/rv/monitors/wwnr/wwnr.h
new file mode 100644
index 000000000..118e576b9
--- /dev/null
+++ b/kernel/trace/rv/monitors/wwnr/wwnr.h
@@ -0,0 +1,46 @@
+/*
+ * Automatically generated C representation of wwnr automaton
+ * For further information about this format, see kernel documentation:
+ *   Documentation/trace/rv/deterministic_automata.rst
+ */
+
+enum states_wwnr {
+	not_running_wwnr = 0,
+	running_wwnr,
+	state_max_wwnr
+};
+
+#define INVALID_STATE state_max_wwnr
+
+enum events_wwnr {
+	switch_in_wwnr = 0,
+	switch_out_wwnr,
+	wakeup_wwnr,
+	event_max_wwnr
+};
+
+struct automaton_wwnr {
+	char *state_names[state_max_wwnr];
+	char *event_names[event_max_wwnr];
+	unsigned char function[state_max_wwnr][event_max_wwnr];
+	unsigned char initial_state;
+	bool final_states[state_max_wwnr];
+};
+
+static struct automaton_wwnr automaton_wwnr = {
+	.state_names = {
+		"not_running",
+		"running"
+	},
+	.event_names = {
+		"switch_in",
+		"switch_out",
+		"wakeup"
+	},
+	.function = {
+		{       running_wwnr,      INVALID_STATE,   not_running_wwnr },
+		{      INVALID_STATE,   not_running_wwnr,      INVALID_STATE },
+	},
+	.initial_state = not_running_wwnr,
+	.final_states = { 1, 0 },
+};
diff --git a/kernel/trace/rv/reactor_panic.c b/kernel/trace/rv/reactor_panic.c
new file mode 100644
index 000000000..d65f6c25a
--- /dev/null
+++ b/kernel/trace/rv/reactor_panic.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@kernel.org>
+ *
+ * Panic RV reactor:
+ *   Prints the exception msg to the kernel message log and panic().
+ */
+
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+
+static void rv_panic_reaction(char *msg)
+{
+	panic(msg);
+}
+
+static struct rv_reactor rv_panic = {
+	.name = "panic",
+	.description = "panic the system if an exception is found.",
+	.react = rv_panic_reaction
+};
+
+static int __init register_react_panic(void)
+{
+	rv_register_reactor(&rv_panic);
+	return 0;
+}
+
+static void __exit unregister_react_panic(void)
+{
+	rv_unregister_reactor(&rv_panic);
+}
+
+module_init(register_react_panic);
+module_exit(unregister_react_panic);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Daniel Bristot de Oliveira");
+MODULE_DESCRIPTION("panic rv reactor: panic if an exception is found.");
diff --git a/kernel/trace/rv/reactor_printk.c b/kernel/trace/rv/reactor_printk.c
new file mode 100644
index 000000000..4b6b7106a
--- /dev/null
+++ b/kernel/trace/rv/reactor_printk.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@kernel.org>
+ *
+ * Printk RV reactor:
+ *   Prints the exception msg to the kernel message log.
+ */
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+
+static void rv_printk_reaction(char *msg)
+{
+	printk_deferred(msg);
+}
+
+static struct rv_reactor rv_printk = {
+	.name = "printk",
+	.description = "prints the exception msg to the kernel message log.",
+	.react = rv_printk_reaction
+};
+
+static int __init register_react_printk(void)
+{
+	rv_register_reactor(&rv_printk);
+	return 0;
+}
+
+static void __exit unregister_react_printk(void)
+{
+	rv_unregister_reactor(&rv_printk);
+}
+
+module_init(register_react_printk);
+module_exit(unregister_react_printk);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Daniel Bristot de Oliveira");
+MODULE_DESCRIPTION("printk rv reactor: printk if an exception is hit.");
diff --git a/kernel/trace/rv/rv.c b/kernel/trace/rv/rv.c
new file mode 100644
index 000000000..6c97cc2d7
--- /dev/null
+++ b/kernel/trace/rv/rv.c
@@ -0,0 +1,799 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@kernel.org>
+ *
+ * This is the online Runtime Verification (RV) interface.
+ *
+ * RV is a lightweight (yet rigorous) method that complements classical
+ * exhaustive verification techniques (such as model checking and
+ * theorem proving) with a more practical approach to complex systems.
+ *
+ * RV works by analyzing the trace of the system's actual execution,
+ * comparing it against a formal specification of the system behavior.
+ * RV can give precise information on the runtime behavior of the
+ * monitored system while enabling the reaction for unexpected
+ * events, avoiding, for example, the propagation of a failure on
+ * safety-critical systems.
+ *
+ * The development of this interface roots in the development of the
+ * paper:
+ *
+ * De Oliveira, Daniel Bristot; Cucinotta, Tommaso; De Oliveira, Romulo
+ * Silva. Efficient formal verification for the Linux kernel. In:
+ * International Conference on Software Engineering and Formal Methods.
+ * Springer, Cham, 2019. p. 315-332.
+ *
+ * And:
+ *
+ * De Oliveira, Daniel Bristot, et al. Automata-based formal analysis
+ * and verification of the real-time Linux kernel. PhD Thesis, 2020.
+ *
+ * == Runtime monitor interface ==
+ *
+ * A monitor is the central part of the runtime verification of a system.
+ *
+ * The monitor stands in between the formal specification of the desired
+ * (or undesired) behavior, and the trace of the actual system.
+ *
+ * In Linux terms, the runtime verification monitors are encapsulated
+ * inside the "RV monitor" abstraction. A RV monitor includes a reference
+ * model of the system, a set of instances of the monitor (per-cpu monitor,
+ * per-task monitor, and so on), and the helper functions that glue the
+ * monitor to the system via trace. Generally, a monitor includes some form
+ * of trace output as a reaction for event parsing and exceptions,
+ * as depicted bellow:
+ *
+ * Linux  +----- RV Monitor ----------------------------------+ Formal
+ *  Realm |                                                   |  Realm
+ *  +-------------------+     +----------------+     +-----------------+
+ *  |   Linux kernel    |     |     Monitor    |     |     Reference   |
+ *  |     Tracing       |  -> |   Instance(s)  | <-  |       Model     |
+ *  | (instrumentation) |     | (verification) |     | (specification) |
+ *  +-------------------+     +----------------+     +-----------------+
+ *         |                          |                       |
+ *         |                          V                       |
+ *         |                     +----------+                 |
+ *         |                     | Reaction |                 |
+ *         |                     +--+--+--+-+                 |
+ *         |                        |  |  |                   |
+ *         |                        |  |  +-> trace output ?  |
+ *         +------------------------|--|----------------------+
+ *                                  |  +----> panic ?
+ *                                  +-------> <user-specified>
+ *
+ * This file implements the interface for loading RV monitors, and
+ * to control the verification session.
+ *
+ * == Registering monitors ==
+ *
+ * The struct rv_monitor defines a set of callback functions to control
+ * a verification session. For instance, when a given monitor is enabled,
+ * the "enable" callback function is called to hook the instrumentation
+ * functions to the kernel trace events. The "disable" function is called
+ * when disabling the verification session.
+ *
+ * A RV monitor is registered via:
+ *   int rv_register_monitor(struct rv_monitor *monitor);
+ * And unregistered via:
+ *   int rv_unregister_monitor(struct rv_monitor *monitor);
+ *
+ * == User interface ==
+ *
+ * The user interface resembles kernel tracing interface. It presents
+ * these files:
+ *
+ *  "available_monitors"
+ *    - List the available monitors, one per line.
+ *
+ *    For example:
+ *      # cat available_monitors
+ *      wip
+ *      wwnr
+ *
+ *  "enabled_monitors"
+ *    - Lists the enabled monitors, one per line;
+ *    - Writing to it enables a given monitor;
+ *    - Writing a monitor name with a '!' prefix disables it;
+ *    - Truncating the file disables all enabled monitors.
+ *
+ *    For example:
+ *      # cat enabled_monitors
+ *      # echo wip > enabled_monitors
+ *      # echo wwnr >> enabled_monitors
+ *      # cat enabled_monitors
+ *      wip
+ *      wwnr
+ *      # echo '!wip' >> enabled_monitors
+ *      # cat enabled_monitors
+ *      wwnr
+ *      # echo > enabled_monitors
+ *      # cat enabled_monitors
+ *      #
+ *
+ *    Note that more than one monitor can be enabled concurrently.
+ *
+ *  "monitoring_on"
+ *    - It is an on/off general switcher for monitoring. Note
+ *    that it does not disable enabled monitors or detach events,
+ *    but stops the per-entity monitors from monitoring the events
+ *    received from the instrumentation. It resembles the "tracing_on"
+ *    switcher.
+ *
+ *  "monitors/"
+ *    Each monitor will have its own directory inside "monitors/". There
+ *    the monitor specific files will be presented.
+ *    The "monitors/" directory resembles the "events" directory on
+ *    tracefs.
+ *
+ *    For example:
+ *      # cd monitors/wip/
+ *      # ls
+ *      desc  enable
+ *      # cat desc
+ *      auto-generated wakeup in preemptive monitor.
+ *      # cat enable
+ *      0
+ *
+ *  For further information, see:
+ *   Documentation/trace/rv/runtime-verification.rst
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+
+#ifdef CONFIG_DA_MON_EVENTS
+#define CREATE_TRACE_POINTS
+#include <trace/events/rv.h>
+#endif
+
+#include "rv.h"
+
+DEFINE_MUTEX(rv_interface_lock);
+
+static struct rv_interface rv_root;
+
+struct dentry *get_monitors_root(void)
+{
+	return rv_root.monitors_dir;
+}
+
+/*
+ * Interface for the monitor register.
+ */
+static LIST_HEAD(rv_monitors_list);
+
+static int task_monitor_count;
+static bool task_monitor_slots[RV_PER_TASK_MONITORS];
+
+int rv_get_task_monitor_slot(void)
+{
+	int i;
+
+	lockdep_assert_held(&rv_interface_lock);
+
+	if (task_monitor_count == RV_PER_TASK_MONITORS)
+		return -EBUSY;
+
+	task_monitor_count++;
+
+	for (i = 0; i < RV_PER_TASK_MONITORS; i++) {
+		if (task_monitor_slots[i] == false) {
+			task_monitor_slots[i] = true;
+			return i;
+		}
+	}
+
+	WARN_ONCE(1, "RV task_monitor_count and slots are out of sync\n");
+
+	return -EINVAL;
+}
+
+void rv_put_task_monitor_slot(int slot)
+{
+	lockdep_assert_held(&rv_interface_lock);
+
+	if (slot < 0 || slot >= RV_PER_TASK_MONITORS) {
+		WARN_ONCE(1, "RV releasing an invalid slot!: %d\n", slot);
+		return;
+	}
+
+	WARN_ONCE(!task_monitor_slots[slot], "RV releasing unused task_monitor_slots: %d\n",
+		  slot);
+
+	task_monitor_count--;
+	task_monitor_slots[slot] = false;
+}
+
+/*
+ * This section collects the monitor/ files and folders.
+ */
+static ssize_t monitor_enable_read_data(struct file *filp, char __user *user_buf, size_t count,
+					loff_t *ppos)
+{
+	struct rv_monitor_def *mdef = filp->private_data;
+	const char *buff;
+
+	buff = mdef->monitor->enabled ? "1\n" : "0\n";
+
+	return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff)+1);
+}
+
+/*
+ * __rv_disable_monitor - disabled an enabled monitor
+ */
+static int __rv_disable_monitor(struct rv_monitor_def *mdef, bool sync)
+{
+	lockdep_assert_held(&rv_interface_lock);
+
+	if (mdef->monitor->enabled) {
+		mdef->monitor->enabled = 0;
+		mdef->monitor->disable();
+
+		/*
+		 * Wait for the execution of all events to finish.
+		 * Otherwise, the data used by the monitor could
+		 * be inconsistent. i.e., if the monitor is re-enabled.
+		 */
+		if (sync)
+			tracepoint_synchronize_unregister();
+		return 1;
+	}
+	return 0;
+}
+
+/**
+ * rv_disable_monitor - disable a given runtime monitor
+ *
+ * Returns 0 on success.
+ */
+int rv_disable_monitor(struct rv_monitor_def *mdef)
+{
+	__rv_disable_monitor(mdef, true);
+	return 0;
+}
+
+/**
+ * rv_enable_monitor - enable a given runtime monitor
+ *
+ * Returns 0 on success, error otherwise.
+ */
+int rv_enable_monitor(struct rv_monitor_def *mdef)
+{
+	int retval;
+
+	lockdep_assert_held(&rv_interface_lock);
+
+	if (mdef->monitor->enabled)
+		return 0;
+
+	retval = mdef->monitor->enable();
+
+	if (!retval)
+		mdef->monitor->enabled = 1;
+
+	return retval;
+}
+
+/*
+ * interface for enabling/disabling a monitor.
+ */
+static ssize_t monitor_enable_write_data(struct file *filp, const char __user *user_buf,
+					 size_t count, loff_t *ppos)
+{
+	struct rv_monitor_def *mdef = filp->private_data;
+	int retval;
+	bool val;
+
+	retval = kstrtobool_from_user(user_buf, count, &val);
+	if (retval)
+		return retval;
+
+	retval = count;
+
+	mutex_lock(&rv_interface_lock);
+
+	if (val)
+		retval = rv_enable_monitor(mdef);
+	else
+		retval = rv_disable_monitor(mdef);
+
+	mutex_unlock(&rv_interface_lock);
+
+	return retval ? : count;
+}
+
+static const struct file_operations interface_enable_fops = {
+	.open   = simple_open,
+	.llseek = no_llseek,
+	.write  = monitor_enable_write_data,
+	.read   = monitor_enable_read_data,
+};
+
+/*
+ * Interface to read monitors description.
+ */
+static ssize_t monitor_desc_read_data(struct file *filp, char __user *user_buf, size_t count,
+				      loff_t *ppos)
+{
+	struct rv_monitor_def *mdef = filp->private_data;
+	char buff[256];
+
+	memset(buff, 0, sizeof(buff));
+
+	snprintf(buff, sizeof(buff), "%s\n", mdef->monitor->description);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff) + 1);
+}
+
+static const struct file_operations interface_desc_fops = {
+	.open   = simple_open,
+	.llseek	= no_llseek,
+	.read	= monitor_desc_read_data,
+};
+
+/*
+ * During the registration of a monitor, this function creates
+ * the monitor dir, where the specific options of the monitor
+ * are exposed.
+ */
+static int create_monitor_dir(struct rv_monitor_def *mdef)
+{
+	struct dentry *root = get_monitors_root();
+	const char *name = mdef->monitor->name;
+	struct dentry *tmp;
+	int retval;
+
+	mdef->root_d = rv_create_dir(name, root);
+	if (!mdef->root_d)
+		return -ENOMEM;
+
+	tmp = rv_create_file("enable", RV_MODE_WRITE, mdef->root_d, mdef, &interface_enable_fops);
+	if (!tmp) {
+		retval = -ENOMEM;
+		goto out_remove_root;
+	}
+
+	tmp = rv_create_file("desc", RV_MODE_READ, mdef->root_d, mdef, &interface_desc_fops);
+	if (!tmp) {
+		retval = -ENOMEM;
+		goto out_remove_root;
+	}
+
+	retval = reactor_populate_monitor(mdef);
+	if (retval)
+		goto out_remove_root;
+
+	return 0;
+
+out_remove_root:
+	rv_remove(mdef->root_d);
+	return retval;
+}
+
+/*
+ * Available/Enable monitor shared seq functions.
+ */
+static int monitors_show(struct seq_file *m, void *p)
+{
+	struct rv_monitor_def *mon_def = p;
+
+	seq_printf(m, "%s\n", mon_def->monitor->name);
+	return 0;
+}
+
+/*
+ * Used by the seq file operations at the end of a read
+ * operation.
+ */
+static void monitors_stop(struct seq_file *m, void *p)
+{
+	mutex_unlock(&rv_interface_lock);
+}
+
+/*
+ * Available monitor seq functions.
+ */
+static void *available_monitors_start(struct seq_file *m, loff_t *pos)
+{
+	mutex_lock(&rv_interface_lock);
+	return seq_list_start(&rv_monitors_list, *pos);
+}
+
+static void *available_monitors_next(struct seq_file *m, void *p, loff_t *pos)
+{
+	return seq_list_next(p, &rv_monitors_list, pos);
+}
+
+/*
+ * Enable monitor seq functions.
+ */
+static void *enabled_monitors_next(struct seq_file *m, void *p, loff_t *pos)
+{
+	struct rv_monitor_def *m_def = p;
+
+	(*pos)++;
+
+	list_for_each_entry_continue(m_def, &rv_monitors_list, list) {
+		if (m_def->monitor->enabled)
+			return m_def;
+	}
+
+	return NULL;
+}
+
+static void *enabled_monitors_start(struct seq_file *m, loff_t *pos)
+{
+	struct rv_monitor_def *m_def;
+	loff_t l;
+
+	mutex_lock(&rv_interface_lock);
+
+	if (list_empty(&rv_monitors_list))
+		return NULL;
+
+	m_def = list_entry(&rv_monitors_list, struct rv_monitor_def, list);
+
+	for (l = 0; l <= *pos; ) {
+		m_def = enabled_monitors_next(m, m_def, &l);
+		if (!m_def)
+			break;
+	}
+
+	return m_def;
+}
+
+/*
+ * available/enabled monitors seq definition.
+ */
+static const struct seq_operations available_monitors_seq_ops = {
+	.start	= available_monitors_start,
+	.next	= available_monitors_next,
+	.stop	= monitors_stop,
+	.show	= monitors_show
+};
+
+static const struct seq_operations enabled_monitors_seq_ops = {
+	.start  = enabled_monitors_start,
+	.next   = enabled_monitors_next,
+	.stop   = monitors_stop,
+	.show   = monitors_show
+};
+
+/*
+ * available_monitors interface.
+ */
+static int available_monitors_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &available_monitors_seq_ops);
+};
+
+static const struct file_operations available_monitors_ops = {
+	.open    = available_monitors_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release
+};
+
+/*
+ * enabled_monitors interface.
+ */
+static void disable_all_monitors(void)
+{
+	struct rv_monitor_def *mdef;
+	int enabled = 0;
+
+	mutex_lock(&rv_interface_lock);
+
+	list_for_each_entry(mdef, &rv_monitors_list, list)
+		enabled += __rv_disable_monitor(mdef, false);
+
+	if (enabled) {
+		/*
+		 * Wait for the execution of all events to finish.
+		 * Otherwise, the data used by the monitor could
+		 * be inconsistent. i.e., if the monitor is re-enabled.
+		 */
+		tracepoint_synchronize_unregister();
+	}
+
+	mutex_unlock(&rv_interface_lock);
+}
+
+static int enabled_monitors_open(struct inode *inode, struct file *file)
+{
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
+		disable_all_monitors();
+
+	return seq_open(file, &enabled_monitors_seq_ops);
+};
+
+static ssize_t enabled_monitors_write(struct file *filp, const char __user *user_buf,
+				      size_t count, loff_t *ppos)
+{
+	char buff[MAX_RV_MONITOR_NAME_SIZE + 2];
+	struct rv_monitor_def *mdef;
+	int retval = -EINVAL;
+	bool enable = true;
+	char *ptr = buff;
+	int len;
+
+	if (count < 1 || count > MAX_RV_MONITOR_NAME_SIZE + 1)
+		return -EINVAL;
+
+	memset(buff, 0, sizeof(buff));
+
+	retval = simple_write_to_buffer(buff, sizeof(buff) - 1, ppos, user_buf, count);
+	if (retval < 0)
+		return -EFAULT;
+
+	ptr = strim(buff);
+
+	if (ptr[0] == '!') {
+		enable = false;
+		ptr++;
+	}
+
+	len = strlen(ptr);
+	if (!len)
+		return count;
+
+	mutex_lock(&rv_interface_lock);
+
+	retval = -EINVAL;
+
+	list_for_each_entry(mdef, &rv_monitors_list, list) {
+		if (strcmp(ptr, mdef->monitor->name) != 0)
+			continue;
+
+		/*
+		 * Monitor found!
+		 */
+		if (enable)
+			retval = rv_enable_monitor(mdef);
+		else
+			retval = rv_disable_monitor(mdef);
+
+		if (!retval)
+			retval = count;
+
+		break;
+	}
+
+	mutex_unlock(&rv_interface_lock);
+	return retval;
+}
+
+static const struct file_operations enabled_monitors_ops = {
+	.open		= enabled_monitors_open,
+	.read		= seq_read,
+	.write		= enabled_monitors_write,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+/*
+ * Monitoring on global switcher!
+ */
+static bool __read_mostly monitoring_on;
+
+/**
+ * rv_monitoring_on - checks if monitoring is on
+ *
+ * Returns 1 if on, 0 otherwise.
+ */
+bool rv_monitoring_on(void)
+{
+	/* Ensures that concurrent monitors read consistent monitoring_on */
+	smp_rmb();
+	return READ_ONCE(monitoring_on);
+}
+
+/*
+ * monitoring_on general switcher.
+ */
+static ssize_t monitoring_on_read_data(struct file *filp, char __user *user_buf,
+				       size_t count, loff_t *ppos)
+{
+	const char *buff;
+
+	buff = rv_monitoring_on() ? "1\n" : "0\n";
+
+	return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff) + 1);
+}
+
+static void turn_monitoring_off(void)
+{
+	WRITE_ONCE(monitoring_on, false);
+	/* Ensures that concurrent monitors read consistent monitoring_on */
+	smp_wmb();
+}
+
+static void reset_all_monitors(void)
+{
+	struct rv_monitor_def *mdef;
+
+	list_for_each_entry(mdef, &rv_monitors_list, list) {
+		if (mdef->monitor->enabled)
+			mdef->monitor->reset();
+	}
+}
+
+static void turn_monitoring_on(void)
+{
+	WRITE_ONCE(monitoring_on, true);
+	/* Ensures that concurrent monitors read consistent monitoring_on */
+	smp_wmb();
+}
+
+static void turn_monitoring_on_with_reset(void)
+{
+	lockdep_assert_held(&rv_interface_lock);
+
+	if (rv_monitoring_on())
+		return;
+
+	/*
+	 * Monitors might be out of sync with the system if events were not
+	 * processed because of !rv_monitoring_on().
+	 *
+	 * Reset all monitors, forcing a re-sync.
+	 */
+	reset_all_monitors();
+	turn_monitoring_on();
+}
+
+static ssize_t monitoring_on_write_data(struct file *filp, const char __user *user_buf,
+					size_t count, loff_t *ppos)
+{
+	int retval;
+	bool val;
+
+	retval = kstrtobool_from_user(user_buf, count, &val);
+	if (retval)
+		return retval;
+
+	mutex_lock(&rv_interface_lock);
+
+	if (val)
+		turn_monitoring_on_with_reset();
+	else
+		turn_monitoring_off();
+
+	/*
+	 * Wait for the execution of all events to finish
+	 * before returning to user-space.
+	 */
+	tracepoint_synchronize_unregister();
+
+	mutex_unlock(&rv_interface_lock);
+
+	return count;
+}
+
+static const struct file_operations monitoring_on_fops = {
+	.open   = simple_open,
+	.llseek = no_llseek,
+	.write  = monitoring_on_write_data,
+	.read   = monitoring_on_read_data,
+};
+
+static void destroy_monitor_dir(struct rv_monitor_def *mdef)
+{
+	reactor_cleanup_monitor(mdef);
+	rv_remove(mdef->root_d);
+}
+
+/**
+ * rv_register_monitor - register a rv monitor.
+ * @monitor:    The rv_monitor to be registered.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int rv_register_monitor(struct rv_monitor *monitor)
+{
+	struct rv_monitor_def *r;
+	int retval = 0;
+
+	if (strlen(monitor->name) >= MAX_RV_MONITOR_NAME_SIZE) {
+		pr_info("Monitor %s has a name longer than %d\n", monitor->name,
+			MAX_RV_MONITOR_NAME_SIZE);
+		return -1;
+	}
+
+	mutex_lock(&rv_interface_lock);
+
+	list_for_each_entry(r, &rv_monitors_list, list) {
+		if (strcmp(monitor->name, r->monitor->name) == 0) {
+			pr_info("Monitor %s is already registered\n", monitor->name);
+			retval = -1;
+			goto out_unlock;
+		}
+	}
+
+	r = kzalloc(sizeof(struct rv_monitor_def), GFP_KERNEL);
+	if (!r) {
+		retval = -ENOMEM;
+		goto out_unlock;
+	}
+
+	r->monitor = monitor;
+
+	retval = create_monitor_dir(r);
+	if (retval) {
+		kfree(r);
+		goto out_unlock;
+	}
+
+	list_add_tail(&r->list, &rv_monitors_list);
+
+out_unlock:
+	mutex_unlock(&rv_interface_lock);
+	return retval;
+}
+
+/**
+ * rv_unregister_monitor - unregister a rv monitor.
+ * @monitor:    The rv_monitor to be unregistered.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int rv_unregister_monitor(struct rv_monitor *monitor)
+{
+	struct rv_monitor_def *ptr, *next;
+
+	mutex_lock(&rv_interface_lock);
+
+	list_for_each_entry_safe(ptr, next, &rv_monitors_list, list) {
+		if (strcmp(monitor->name, ptr->monitor->name) == 0) {
+			rv_disable_monitor(ptr);
+			list_del(&ptr->list);
+			destroy_monitor_dir(ptr);
+		}
+	}
+
+	mutex_unlock(&rv_interface_lock);
+	return 0;
+}
+
+int __init rv_init_interface(void)
+{
+	struct dentry *tmp;
+	int retval;
+
+	rv_root.root_dir = rv_create_dir("rv", NULL);
+	if (!rv_root.root_dir)
+		goto out_err;
+
+	rv_root.monitors_dir = rv_create_dir("monitors", rv_root.root_dir);
+	if (!rv_root.monitors_dir)
+		goto out_err;
+
+	tmp = rv_create_file("available_monitors", RV_MODE_READ, rv_root.root_dir, NULL,
+			     &available_monitors_ops);
+	if (!tmp)
+		goto out_err;
+
+	tmp = rv_create_file("enabled_monitors", RV_MODE_WRITE, rv_root.root_dir, NULL,
+			     &enabled_monitors_ops);
+	if (!tmp)
+		goto out_err;
+
+	tmp = rv_create_file("monitoring_on", RV_MODE_WRITE, rv_root.root_dir, NULL,
+			     &monitoring_on_fops);
+	if (!tmp)
+		goto out_err;
+	retval = init_rv_reactors(rv_root.root_dir);
+	if (retval)
+		goto out_err;
+
+	turn_monitoring_on();
+
+	return 0;
+
+out_err:
+	rv_remove(rv_root.root_dir);
+	printk(KERN_ERR "RV: Error while creating the RV interface\n");
+	return 1;
+}
diff --git a/kernel/trace/rv/rv.h b/kernel/trace/rv/rv.h
new file mode 100644
index 000000000..db6cb0913
--- /dev/null
+++ b/kernel/trace/rv/rv.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/mutex.h>
+
+struct rv_interface {
+	struct dentry		*root_dir;
+	struct dentry		*monitors_dir;
+};
+
+#include "../trace.h"
+#include <linux/tracefs.h>
+#include <linux/rv.h>
+
+#define RV_MODE_WRITE			TRACE_MODE_WRITE
+#define RV_MODE_READ			TRACE_MODE_READ
+
+#define rv_create_dir			tracefs_create_dir
+#define rv_create_file			tracefs_create_file
+#define rv_remove			tracefs_remove
+
+#define MAX_RV_MONITOR_NAME_SIZE	32
+#define MAX_RV_REACTOR_NAME_SIZE	32
+
+extern struct mutex rv_interface_lock;
+
+#ifdef CONFIG_RV_REACTORS
+struct rv_reactor_def {
+	struct list_head	list;
+	struct rv_reactor	*reactor;
+	/* protected by the monitor interface lock */
+	int			counter;
+};
+#endif
+
+struct rv_monitor_def {
+	struct list_head	list;
+	struct rv_monitor	*monitor;
+	struct dentry		*root_d;
+#ifdef CONFIG_RV_REACTORS
+	struct rv_reactor_def	*rdef;
+	bool			reacting;
+#endif
+	bool			task_monitor;
+};
+
+struct dentry *get_monitors_root(void);
+int rv_disable_monitor(struct rv_monitor_def *mdef);
+int rv_enable_monitor(struct rv_monitor_def *mdef);
+
+#ifdef CONFIG_RV_REACTORS
+int reactor_populate_monitor(struct rv_monitor_def *mdef);
+void reactor_cleanup_monitor(struct rv_monitor_def *mdef);
+int init_rv_reactors(struct dentry *root_dir);
+#else
+static inline int reactor_populate_monitor(struct rv_monitor_def *mdef)
+{
+	return 0;
+}
+
+static inline void reactor_cleanup_monitor(struct rv_monitor_def *mdef)
+{
+	return;
+}
+
+static inline int init_rv_reactors(struct dentry *root_dir)
+{
+	return 0;
+}
+#endif
diff --git a/kernel/trace/rv/rv_reactors.c b/kernel/trace/rv/rv_reactors.c
new file mode 100644
index 000000000..6aae10669
--- /dev/null
+++ b/kernel/trace/rv/rv_reactors.c
@@ -0,0 +1,510 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@kernel.org>
+ *
+ * Runtime reactor interface.
+ *
+ * A runtime monitor can cause a reaction to the detection of an
+ * exception on the model's execution. By default, the monitors have
+ * tracing reactions, printing the monitor output via tracepoints.
+ * But other reactions can be added (on-demand) via this interface.
+ *
+ * == Registering reactors ==
+ *
+ * The struct rv_reactor defines a callback function to be executed
+ * in case of a model exception happens. The callback function
+ * receives a message to be (optionally) printed before executing
+ * the reaction.
+ *
+ * A RV reactor is registered via:
+ *   int rv_register_reactor(struct rv_reactor *reactor)
+ * And unregistered via:
+ *   int rv_unregister_reactor(struct rv_reactor *reactor)
+ *
+ * These functions are exported to modules, enabling reactors to be
+ * dynamically loaded.
+ *
+ * == User interface ==
+ *
+ * The user interface resembles the kernel tracing interface and
+ * presents these files:
+ *
+ *  "available_reactors"
+ *    - List the available reactors, one per line.
+ *
+ *    For example:
+ *      # cat available_reactors
+ *      nop
+ *      panic
+ *      printk
+ *
+ *  "reacting_on"
+ *    - It is an on/off general switch for reactors, disabling
+ *    all reactions.
+ *
+ *  "monitors/MONITOR/reactors"
+ *    - List available reactors, with the select reaction for the given
+ *    MONITOR inside []. The default one is the nop (no operation)
+ *    reactor.
+ *    - Writing the name of an reactor enables it to the given
+ *    MONITOR.
+ *
+ *    For example:
+ *      # cat monitors/wip/reactors
+ *      [nop]
+ *      panic
+ *      printk
+ *      # echo panic > monitors/wip/reactors
+ *      # cat monitors/wip/reactors
+ *      nop
+ *      [panic]
+ *      printk
+ */
+
+#include <linux/slab.h>
+
+#include "rv.h"
+
+/*
+ * Interface for the reactor register.
+ */
+static LIST_HEAD(rv_reactors_list);
+
+static struct rv_reactor_def *get_reactor_rdef_by_name(char *name)
+{
+	struct rv_reactor_def *r;
+
+	list_for_each_entry(r, &rv_reactors_list, list) {
+		if (strcmp(name, r->reactor->name) == 0)
+			return r;
+	}
+	return NULL;
+}
+
+/*
+ * Available reactors seq functions.
+ */
+static int reactors_show(struct seq_file *m, void *p)
+{
+	struct rv_reactor_def *rea_def = p;
+
+	seq_printf(m, "%s\n", rea_def->reactor->name);
+	return 0;
+}
+
+static void reactors_stop(struct seq_file *m, void *p)
+{
+	mutex_unlock(&rv_interface_lock);
+}
+
+static void *reactors_start(struct seq_file *m, loff_t *pos)
+{
+	mutex_lock(&rv_interface_lock);
+	return seq_list_start(&rv_reactors_list, *pos);
+}
+
+static void *reactors_next(struct seq_file *m, void *p, loff_t *pos)
+{
+	return seq_list_next(p, &rv_reactors_list, pos);
+}
+
+/*
+ * available_reactors seq definition.
+ */
+static const struct seq_operations available_reactors_seq_ops = {
+	.start	= reactors_start,
+	.next	= reactors_next,
+	.stop	= reactors_stop,
+	.show	= reactors_show
+};
+
+/*
+ * available_reactors interface.
+ */
+static int available_reactors_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &available_reactors_seq_ops);
+};
+
+static const struct file_operations available_reactors_ops = {
+	.open    = available_reactors_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release
+};
+
+/*
+ * Monitor's reactor file.
+ */
+static int monitor_reactor_show(struct seq_file *m, void *p)
+{
+	struct rv_monitor_def *mdef = m->private;
+	struct rv_reactor_def *rdef = p;
+
+	if (mdef->rdef == rdef)
+		seq_printf(m, "[%s]\n", rdef->reactor->name);
+	else
+		seq_printf(m, "%s\n", rdef->reactor->name);
+	return 0;
+}
+
+/*
+ * available_reactors seq definition.
+ */
+static const struct seq_operations monitor_reactors_seq_ops = {
+	.start	= reactors_start,
+	.next	= reactors_next,
+	.stop	= reactors_stop,
+	.show	= monitor_reactor_show
+};
+
+static void monitor_swap_reactors(struct rv_monitor_def *mdef, struct rv_reactor_def *rdef,
+				    bool reacting)
+{
+	bool monitor_enabled;
+
+	/* nothing to do */
+	if (mdef->rdef == rdef)
+		return;
+
+	monitor_enabled = mdef->monitor->enabled;
+	if (monitor_enabled)
+		rv_disable_monitor(mdef);
+
+	/* swap reactor's usage */
+	mdef->rdef->counter--;
+	rdef->counter++;
+
+	mdef->rdef = rdef;
+	mdef->reacting = reacting;
+	mdef->monitor->react = rdef->reactor->react;
+
+	if (monitor_enabled)
+		rv_enable_monitor(mdef);
+}
+
+static ssize_t
+monitor_reactors_write(struct file *file, const char __user *user_buf,
+		      size_t count, loff_t *ppos)
+{
+	char buff[MAX_RV_REACTOR_NAME_SIZE + 2];
+	struct rv_monitor_def *mdef;
+	struct rv_reactor_def *rdef;
+	struct seq_file *seq_f;
+	int retval = -EINVAL;
+	bool enable;
+	char *ptr;
+	int len;
+
+	if (count < 1 || count > MAX_RV_REACTOR_NAME_SIZE + 1)
+		return -EINVAL;
+
+	memset(buff, 0, sizeof(buff));
+
+	retval = simple_write_to_buffer(buff, sizeof(buff) - 1, ppos, user_buf, count);
+	if (retval < 0)
+		return -EFAULT;
+
+	ptr = strim(buff);
+
+	len = strlen(ptr);
+	if (!len)
+		return count;
+
+	/*
+	 * See monitor_reactors_open()
+	 */
+	seq_f = file->private_data;
+	mdef = seq_f->private;
+
+	mutex_lock(&rv_interface_lock);
+
+	retval = -EINVAL;
+
+	list_for_each_entry(rdef, &rv_reactors_list, list) {
+		if (strcmp(ptr, rdef->reactor->name) != 0)
+			continue;
+
+		if (rdef == get_reactor_rdef_by_name("nop"))
+			enable = false;
+		else
+			enable = true;
+
+		monitor_swap_reactors(mdef, rdef, enable);
+
+		retval = count;
+		break;
+	}
+
+	mutex_unlock(&rv_interface_lock);
+
+	return retval;
+}
+
+/*
+ * available_reactors interface.
+ */
+static int monitor_reactors_open(struct inode *inode, struct file *file)
+{
+	struct rv_monitor_def *mdef = inode->i_private;
+	struct seq_file *seq_f;
+	int ret;
+
+	ret = seq_open(file, &monitor_reactors_seq_ops);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * seq_open stores the seq_file on the file->private data.
+	 */
+	seq_f = file->private_data;
+
+	/*
+	 * Copy the create file "private" data to the seq_file private data.
+	 */
+	seq_f->private = mdef;
+
+	return 0;
+};
+
+static const struct file_operations monitor_reactors_ops = {
+	.open    = monitor_reactors_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release,
+	.write = monitor_reactors_write
+};
+
+static int __rv_register_reactor(struct rv_reactor *reactor)
+{
+	struct rv_reactor_def *r;
+
+	list_for_each_entry(r, &rv_reactors_list, list) {
+		if (strcmp(reactor->name, r->reactor->name) == 0) {
+			pr_info("Reactor %s is already registered\n", reactor->name);
+			return -EINVAL;
+		}
+	}
+
+	r = kzalloc(sizeof(struct rv_reactor_def), GFP_KERNEL);
+	if (!r)
+		return -ENOMEM;
+
+	r->reactor = reactor;
+	r->counter = 0;
+
+	list_add_tail(&r->list, &rv_reactors_list);
+
+	return 0;
+}
+
+/**
+ * rv_register_reactor - register a rv reactor.
+ * @reactor:	The rv_reactor to be registered.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int rv_register_reactor(struct rv_reactor *reactor)
+{
+	int retval = 0;
+
+	if (strlen(reactor->name) >= MAX_RV_REACTOR_NAME_SIZE) {
+		pr_info("Reactor %s has a name longer than %d\n",
+			reactor->name, MAX_RV_MONITOR_NAME_SIZE);
+		return -EINVAL;
+	}
+
+	mutex_lock(&rv_interface_lock);
+	retval = __rv_register_reactor(reactor);
+	mutex_unlock(&rv_interface_lock);
+	return retval;
+}
+
+/**
+ * rv_unregister_reactor - unregister a rv reactor.
+ * @reactor:	The rv_reactor to be unregistered.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int rv_unregister_reactor(struct rv_reactor *reactor)
+{
+	struct rv_reactor_def *ptr, *next;
+	int ret = 0;
+
+	mutex_lock(&rv_interface_lock);
+
+	list_for_each_entry_safe(ptr, next, &rv_reactors_list, list) {
+		if (strcmp(reactor->name, ptr->reactor->name) == 0) {
+
+			if (!ptr->counter) {
+				list_del(&ptr->list);
+			} else {
+				printk(KERN_WARNING
+				       "rv: the rv_reactor %s is in use by %d monitor(s)\n",
+				       ptr->reactor->name, ptr->counter);
+				printk(KERN_WARNING "rv: the rv_reactor %s cannot be removed\n",
+				       ptr->reactor->name);
+				ret = -EBUSY;
+				break;
+			}
+		}
+	}
+
+	mutex_unlock(&rv_interface_lock);
+	return ret;
+}
+
+/*
+ * reacting_on interface.
+ */
+static bool __read_mostly reacting_on;
+
+/**
+ * rv_reacting_on - checks if reacting is on
+ *
+ * Returns 1 if on, 0 otherwise.
+ */
+bool rv_reacting_on(void)
+{
+	/* Ensures that concurrent monitors read consistent reacting_on */
+	smp_rmb();
+	return READ_ONCE(reacting_on);
+}
+
+static ssize_t reacting_on_read_data(struct file *filp,
+				     char __user *user_buf,
+				     size_t count, loff_t *ppos)
+{
+	char *buff;
+
+	buff = rv_reacting_on() ? "1\n" : "0\n";
+
+	return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff)+1);
+}
+
+static void turn_reacting_off(void)
+{
+	WRITE_ONCE(reacting_on, false);
+	/* Ensures that concurrent monitors read consistent reacting_on */
+	smp_wmb();
+}
+
+static void turn_reacting_on(void)
+{
+	WRITE_ONCE(reacting_on, true);
+	/* Ensures that concurrent monitors read consistent reacting_on */
+	smp_wmb();
+}
+
+static ssize_t reacting_on_write_data(struct file *filp, const char __user *user_buf,
+				      size_t count, loff_t *ppos)
+{
+	int retval;
+	bool val;
+
+	retval = kstrtobool_from_user(user_buf, count, &val);
+	if (retval)
+		return retval;
+
+	mutex_lock(&rv_interface_lock);
+
+	if (val)
+		turn_reacting_on();
+	else
+		turn_reacting_off();
+
+	/*
+	 * Wait for the execution of all events to finish
+	 * before returning to user-space.
+	 */
+	tracepoint_synchronize_unregister();
+
+	mutex_unlock(&rv_interface_lock);
+
+	return count;
+}
+
+static const struct file_operations reacting_on_fops = {
+	.open   = simple_open,
+	.llseek = no_llseek,
+	.write  = reacting_on_write_data,
+	.read   = reacting_on_read_data,
+};
+
+/**
+ * reactor_populate_monitor - creates per monitor reactors file
+ * @mdef:	monitor's definition.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int reactor_populate_monitor(struct rv_monitor_def *mdef)
+{
+	struct dentry *tmp;
+
+	tmp = rv_create_file("reactors", RV_MODE_WRITE, mdef->root_d, mdef, &monitor_reactors_ops);
+	if (!tmp)
+		return -ENOMEM;
+
+	/*
+	 * Configure as the rv_nop reactor.
+	 */
+	mdef->rdef = get_reactor_rdef_by_name("nop");
+	mdef->rdef->counter++;
+	mdef->reacting = false;
+
+	return 0;
+}
+
+/**
+ * reactor_cleanup_monitor - cleanup a monitor reference
+ * @mdef:       monitor's definition.
+ */
+void reactor_cleanup_monitor(struct rv_monitor_def *mdef)
+{
+	lockdep_assert_held(&rv_interface_lock);
+	mdef->rdef->counter--;
+	WARN_ON_ONCE(mdef->rdef->counter < 0);
+}
+
+/*
+ * Nop reactor register
+ */
+static void rv_nop_reaction(char *msg)
+{
+}
+
+static struct rv_reactor rv_nop = {
+	.name = "nop",
+	.description = "no-operation reactor: do nothing.",
+	.react = rv_nop_reaction
+};
+
+int init_rv_reactors(struct dentry *root_dir)
+{
+	struct dentry *available, *reacting;
+	int retval;
+
+	available = rv_create_file("available_reactors", RV_MODE_READ, root_dir, NULL,
+				   &available_reactors_ops);
+	if (!available)
+		goto out_err;
+
+	reacting = rv_create_file("reacting_on", RV_MODE_WRITE, root_dir, NULL, &reacting_on_fops);
+	if (!reacting)
+		goto rm_available;
+
+	retval = __rv_register_reactor(&rv_nop);
+	if (retval)
+		goto rm_reacting;
+
+	turn_reacting_on();
+
+	return 0;
+
+rm_reacting:
+	rv_remove(reacting);
+rm_available:
+	rv_remove(available);
+out_err:
+	return -ENOMEM;
+}
diff --git a/kernel/trace/synth_event_gen_test.c b/kernel/trace/synth_event_gen_test.c
new file mode 100644
index 000000000..d944924cd
--- /dev/null
+++ b/kernel/trace/synth_event_gen_test.c
@@ -0,0 +1,536 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test module for in-kernel synthetic event creation and generation.
+ *
+ * Copyright (C) 2019 Tom Zanussi <zanussi@kernel.org>
+ */
+
+#include <linux/module.h>
+#include <linux/trace_events.h>
+
+/*
+ * This module is a simple test of basic functionality for in-kernel
+ * synthetic event creation and generation, the first and second tests
+ * using synth_event_gen_cmd_start() and synth_event_add_field(), the
+ * third uses synth_event_create() to do it all at once with a static
+ * field array.
+ *
+ * Following that are a few examples using the created events to test
+ * various ways of tracing a synthetic event.
+ *
+ * To test, select CONFIG_SYNTH_EVENT_GEN_TEST and build the module.
+ * Then:
+ *
+ * # insmod kernel/trace/synth_event_gen_test.ko
+ * # cat /sys/kernel/debug/tracing/trace
+ *
+ * You should see several events in the trace buffer -
+ * "create_synth_test", "empty_synth_test", and several instances of
+ * "gen_synth_test".
+ *
+ * To remove the events, remove the module:
+ *
+ * # rmmod synth_event_gen_test
+ *
+ */
+
+static struct trace_event_file *create_synth_test;
+static struct trace_event_file *empty_synth_test;
+static struct trace_event_file *gen_synth_test;
+
+/*
+ * Test to make sure we can create a synthetic event, then add more
+ * fields.
+ */
+static int __init test_gen_synth_cmd(void)
+{
+	struct dynevent_cmd cmd;
+	u64 vals[7];
+	char *buf;
+	int ret;
+
+	/* Create a buffer to hold the generated command */
+	buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	/* Before generating the command, initialize the cmd object */
+	synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
+
+	/*
+	 * Create the empty gen_synth_test synthetic event with the
+	 * first 4 fields.
+	 */
+	ret = synth_event_gen_cmd_start(&cmd, "gen_synth_test", THIS_MODULE,
+					"pid_t", "next_pid_field",
+					"char[16]", "next_comm_field",
+					"u64", "ts_ns",
+					"u64", "ts_ms");
+	if (ret)
+		goto free;
+
+	/* Use synth_event_add_field to add the rest of the fields */
+
+	ret = synth_event_add_field(&cmd, "unsigned int", "cpu");
+	if (ret)
+		goto free;
+
+	ret = synth_event_add_field(&cmd, "char[64]", "my_string_field");
+	if (ret)
+		goto free;
+
+	ret = synth_event_add_field(&cmd, "int", "my_int_field");
+	if (ret)
+		goto free;
+
+	ret = synth_event_gen_cmd_end(&cmd);
+	if (ret)
+		goto free;
+
+	/*
+	 * Now get the gen_synth_test event file.  We need to prevent
+	 * the instance and event from disappearing from underneath
+	 * us, which trace_get_event_file() does (though in this case
+	 * we're using the top-level instance which never goes away).
+	 */
+	gen_synth_test = trace_get_event_file(NULL, "synthetic",
+					      "gen_synth_test");
+	if (IS_ERR(gen_synth_test)) {
+		ret = PTR_ERR(gen_synth_test);
+		goto delete;
+	}
+
+	/* Enable the event or you won't see anything */
+	ret = trace_array_set_clr_event(gen_synth_test->tr,
+					"synthetic", "gen_synth_test", true);
+	if (ret) {
+		trace_put_event_file(gen_synth_test);
+		goto delete;
+	}
+
+	/* Create some bogus values just for testing */
+
+	vals[0] = 777;			/* next_pid_field */
+	vals[1] = (u64)(long)"hula hoops";	/* next_comm_field */
+	vals[2] = 1000000;		/* ts_ns */
+	vals[3] = 1000;			/* ts_ms */
+	vals[4] = raw_smp_processor_id(); /* cpu */
+	vals[5] = (u64)(long)"thneed";	/* my_string_field */
+	vals[6] = 598;			/* my_int_field */
+
+	/* Now generate a gen_synth_test event */
+	ret = synth_event_trace_array(gen_synth_test, vals, ARRAY_SIZE(vals));
+ free:
+	kfree(buf);
+	return ret;
+ delete:
+	/* We got an error after creating the event, delete it */
+	synth_event_delete("gen_synth_test");
+	goto free;
+}
+
+/*
+ * Test to make sure we can create an initially empty synthetic event,
+ * then add all the fields.
+ */
+static int __init test_empty_synth_event(void)
+{
+	struct dynevent_cmd cmd;
+	u64 vals[7];
+	char *buf;
+	int ret;
+
+	/* Create a buffer to hold the generated command */
+	buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	/* Before generating the command, initialize the cmd object */
+	synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
+
+	/*
+	 * Create the empty_synth_test synthetic event with no fields.
+	 */
+	ret = synth_event_gen_cmd_start(&cmd, "empty_synth_test", THIS_MODULE);
+	if (ret)
+		goto free;
+
+	/* Use synth_event_add_field to add all of the fields */
+
+	ret = synth_event_add_field(&cmd, "pid_t", "next_pid_field");
+	if (ret)
+		goto free;
+
+	ret = synth_event_add_field(&cmd, "char[16]", "next_comm_field");
+	if (ret)
+		goto free;
+
+	ret = synth_event_add_field(&cmd, "u64", "ts_ns");
+	if (ret)
+		goto free;
+
+	ret = synth_event_add_field(&cmd, "u64", "ts_ms");
+	if (ret)
+		goto free;
+
+	ret = synth_event_add_field(&cmd, "unsigned int", "cpu");
+	if (ret)
+		goto free;
+
+	ret = synth_event_add_field(&cmd, "char[64]", "my_string_field");
+	if (ret)
+		goto free;
+
+	ret = synth_event_add_field(&cmd, "int", "my_int_field");
+	if (ret)
+		goto free;
+
+	/* All fields have been added, close and register the synth event */
+
+	ret = synth_event_gen_cmd_end(&cmd);
+	if (ret)
+		goto free;
+
+	/*
+	 * Now get the empty_synth_test event file.  We need to
+	 * prevent the instance and event from disappearing from
+	 * underneath us, which trace_get_event_file() does (though in
+	 * this case we're using the top-level instance which never
+	 * goes away).
+	 */
+	empty_synth_test = trace_get_event_file(NULL, "synthetic",
+						"empty_synth_test");
+	if (IS_ERR(empty_synth_test)) {
+		ret = PTR_ERR(empty_synth_test);
+		goto delete;
+	}
+
+	/* Enable the event or you won't see anything */
+	ret = trace_array_set_clr_event(empty_synth_test->tr,
+					"synthetic", "empty_synth_test", true);
+	if (ret) {
+		trace_put_event_file(empty_synth_test);
+		goto delete;
+	}
+
+	/* Create some bogus values just for testing */
+
+	vals[0] = 777;			/* next_pid_field */
+	vals[1] = (u64)(long)"tiddlywinks";	/* next_comm_field */
+	vals[2] = 1000000;		/* ts_ns */
+	vals[3] = 1000;			/* ts_ms */
+	vals[4] = raw_smp_processor_id(); /* cpu */
+	vals[5] = (u64)(long)"thneed_2.0";	/* my_string_field */
+	vals[6] = 399;			/* my_int_field */
+
+	/* Now trace an empty_synth_test event */
+	ret = synth_event_trace_array(empty_synth_test, vals, ARRAY_SIZE(vals));
+ free:
+	kfree(buf);
+	return ret;
+ delete:
+	/* We got an error after creating the event, delete it */
+	synth_event_delete("empty_synth_test");
+	goto free;
+}
+
+static struct synth_field_desc create_synth_test_fields[] = {
+	{ .type = "pid_t",		.name = "next_pid_field" },
+	{ .type = "char[16]",		.name = "next_comm_field" },
+	{ .type = "u64",		.name = "ts_ns" },
+	{ .type = "char[]",		.name = "dynstring_field_1" },
+	{ .type = "u64",		.name = "ts_ms" },
+	{ .type = "unsigned int",	.name = "cpu" },
+	{ .type = "char[64]",		.name = "my_string_field" },
+	{ .type = "char[]",		.name = "dynstring_field_2" },
+	{ .type = "int",		.name = "my_int_field" },
+};
+
+/*
+ * Test synthetic event creation all at once from array of field
+ * descriptors.
+ */
+static int __init test_create_synth_event(void)
+{
+	u64 vals[9];
+	int ret;
+
+	/* Create the create_synth_test event with the fields above */
+	ret = synth_event_create("create_synth_test",
+				 create_synth_test_fields,
+				 ARRAY_SIZE(create_synth_test_fields),
+				 THIS_MODULE);
+	if (ret)
+		goto out;
+
+	/*
+	 * Now get the create_synth_test event file.  We need to
+	 * prevent the instance and event from disappearing from
+	 * underneath us, which trace_get_event_file() does (though in
+	 * this case we're using the top-level instance which never
+	 * goes away).
+	 */
+	create_synth_test = trace_get_event_file(NULL, "synthetic",
+						 "create_synth_test");
+	if (IS_ERR(create_synth_test)) {
+		ret = PTR_ERR(create_synth_test);
+		goto delete;
+	}
+
+	/* Enable the event or you won't see anything */
+	ret = trace_array_set_clr_event(create_synth_test->tr,
+					"synthetic", "create_synth_test", true);
+	if (ret) {
+		trace_put_event_file(create_synth_test);
+		goto delete;
+	}
+
+	/* Create some bogus values just for testing */
+
+	vals[0] = 777;			/* next_pid_field */
+	vals[1] = (u64)(long)"tiddlywinks";	/* next_comm_field */
+	vals[2] = 1000000;		/* ts_ns */
+	vals[3] = (u64)(long)"xrayspecs";	/* dynstring_field_1 */
+	vals[4] = 1000;			/* ts_ms */
+	vals[5] = raw_smp_processor_id(); /* cpu */
+	vals[6] = (u64)(long)"thneed";	/* my_string_field */
+	vals[7] = (u64)(long)"kerplunk";	/* dynstring_field_2 */
+	vals[8] = 398;			/* my_int_field */
+
+	/* Now generate a create_synth_test event */
+	ret = synth_event_trace_array(create_synth_test, vals, ARRAY_SIZE(vals));
+ out:
+	return ret;
+ delete:
+	/* We got an error after creating the event, delete it */
+	synth_event_delete("create_synth_test");
+
+	goto out;
+}
+
+/*
+ * Test tracing a synthetic event by reserving trace buffer space,
+ * then filling in fields one after another.
+ */
+static int __init test_add_next_synth_val(void)
+{
+	struct synth_event_trace_state trace_state;
+	int ret;
+
+	/* Start by reserving space in the trace buffer */
+	ret = synth_event_trace_start(gen_synth_test, &trace_state);
+	if (ret)
+		return ret;
+
+	/* Write some bogus values into the trace buffer, one after another */
+
+	/* next_pid_field */
+	ret = synth_event_add_next_val(777, &trace_state);
+	if (ret)
+		goto out;
+
+	/* next_comm_field */
+	ret = synth_event_add_next_val((u64)(long)"slinky", &trace_state);
+	if (ret)
+		goto out;
+
+	/* ts_ns */
+	ret = synth_event_add_next_val(1000000, &trace_state);
+	if (ret)
+		goto out;
+
+	/* ts_ms */
+	ret = synth_event_add_next_val(1000, &trace_state);
+	if (ret)
+		goto out;
+
+	/* cpu */
+	ret = synth_event_add_next_val(raw_smp_processor_id(), &trace_state);
+	if (ret)
+		goto out;
+
+	/* my_string_field */
+	ret = synth_event_add_next_val((u64)(long)"thneed_2.01", &trace_state);
+	if (ret)
+		goto out;
+
+	/* my_int_field */
+	ret = synth_event_add_next_val(395, &trace_state);
+ out:
+	/* Finally, commit the event */
+	ret = synth_event_trace_end(&trace_state);
+
+	return ret;
+}
+
+/*
+ * Test tracing a synthetic event by reserving trace buffer space,
+ * then filling in fields using field names, which can be done in any
+ * order.
+ */
+static int __init test_add_synth_val(void)
+{
+	struct synth_event_trace_state trace_state;
+	int ret;
+
+	/* Start by reserving space in the trace buffer */
+	ret = synth_event_trace_start(gen_synth_test, &trace_state);
+	if (ret)
+		return ret;
+
+	/* Write some bogus values into the trace buffer, using field names */
+
+	ret = synth_event_add_val("ts_ns", 1000000, &trace_state);
+	if (ret)
+		goto out;
+
+	ret = synth_event_add_val("ts_ms", 1000, &trace_state);
+	if (ret)
+		goto out;
+
+	ret = synth_event_add_val("cpu", raw_smp_processor_id(), &trace_state);
+	if (ret)
+		goto out;
+
+	ret = synth_event_add_val("next_pid_field", 777, &trace_state);
+	if (ret)
+		goto out;
+
+	ret = synth_event_add_val("next_comm_field", (u64)(long)"silly putty",
+				  &trace_state);
+	if (ret)
+		goto out;
+
+	ret = synth_event_add_val("my_string_field", (u64)(long)"thneed_9",
+				  &trace_state);
+	if (ret)
+		goto out;
+
+	ret = synth_event_add_val("my_int_field", 3999, &trace_state);
+ out:
+	/* Finally, commit the event */
+	ret = synth_event_trace_end(&trace_state);
+
+	return ret;
+}
+
+/*
+ * Test tracing a synthetic event all at once from array of values.
+ */
+static int __init test_trace_synth_event(void)
+{
+	int ret;
+
+	/* Trace some bogus values just for testing */
+	ret = synth_event_trace(create_synth_test, 9,	/* number of values */
+				(u64)444,		/* next_pid_field */
+				(u64)(long)"clackers",	/* next_comm_field */
+				(u64)1000000,		/* ts_ns */
+				(u64)(long)"viewmaster",/* dynstring_field_1 */
+				(u64)1000,		/* ts_ms */
+				(u64)raw_smp_processor_id(), /* cpu */
+				(u64)(long)"Thneed",	/* my_string_field */
+				(u64)(long)"yoyos",	/* dynstring_field_2 */
+				(u64)999);		/* my_int_field */
+	return ret;
+}
+
+static int __init synth_event_gen_test_init(void)
+{
+	int ret;
+
+	ret = test_gen_synth_cmd();
+	if (ret)
+		return ret;
+
+	ret = test_empty_synth_event();
+	if (ret) {
+		WARN_ON(trace_array_set_clr_event(gen_synth_test->tr,
+						  "synthetic",
+						  "gen_synth_test", false));
+		trace_put_event_file(gen_synth_test);
+		WARN_ON(synth_event_delete("gen_synth_test"));
+		goto out;
+	}
+
+	ret = test_create_synth_event();
+	if (ret) {
+		WARN_ON(trace_array_set_clr_event(gen_synth_test->tr,
+						  "synthetic",
+						  "gen_synth_test", false));
+		trace_put_event_file(gen_synth_test);
+		WARN_ON(synth_event_delete("gen_synth_test"));
+
+		WARN_ON(trace_array_set_clr_event(empty_synth_test->tr,
+						  "synthetic",
+						  "empty_synth_test", false));
+		trace_put_event_file(empty_synth_test);
+		WARN_ON(synth_event_delete("empty_synth_test"));
+		goto out;
+	}
+
+	ret = test_add_next_synth_val();
+	WARN_ON(ret);
+
+	ret = test_add_synth_val();
+	WARN_ON(ret);
+
+	ret = test_trace_synth_event();
+	WARN_ON(ret);
+
+	/* Disable when done */
+	trace_array_set_clr_event(gen_synth_test->tr,
+				  "synthetic",
+				  "gen_synth_test", false);
+	trace_array_set_clr_event(empty_synth_test->tr,
+				  "synthetic",
+				  "empty_synth_test", false);
+	trace_array_set_clr_event(create_synth_test->tr,
+				  "synthetic",
+				  "create_synth_test", false);
+ out:
+	return ret;
+}
+
+static void __exit synth_event_gen_test_exit(void)
+{
+	/* Disable the event or you can't remove it */
+	WARN_ON(trace_array_set_clr_event(gen_synth_test->tr,
+					  "synthetic",
+					  "gen_synth_test", false));
+
+	/* Now give the file and instance back */
+	trace_put_event_file(gen_synth_test);
+
+	/* Now unregister and free the synthetic event */
+	WARN_ON(synth_event_delete("gen_synth_test"));
+
+	/* Disable the event or you can't remove it */
+	WARN_ON(trace_array_set_clr_event(empty_synth_test->tr,
+					  "synthetic",
+					  "empty_synth_test", false));
+
+	/* Now give the file and instance back */
+	trace_put_event_file(empty_synth_test);
+
+	/* Now unregister and free the synthetic event */
+	WARN_ON(synth_event_delete("empty_synth_test"));
+
+	/* Disable the event or you can't remove it */
+	WARN_ON(trace_array_set_clr_event(create_synth_test->tr,
+					  "synthetic",
+					  "create_synth_test", false));
+
+	/* Now give the file and instance back */
+	trace_put_event_file(create_synth_test);
+
+	/* Now unregister and free the synthetic event */
+	WARN_ON(synth_event_delete("create_synth_test"));
+}
+
+module_init(synth_event_gen_test_init)
+module_exit(synth_event_gen_test_exit)
+
+MODULE_AUTHOR("Tom Zanussi");
+MODULE_DESCRIPTION("synthetic event generation test");
+MODULE_LICENSE("GPL v2");
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
new file mode 100644
index 000000000..2b3c4cd83
--- /dev/null
+++ b/kernel/trace/trace.c
@@ -0,0 +1,10482 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ring buffer based function tracer
+ *
+ * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ *
+ * Originally taken from the RT patch by:
+ *    Arnaldo Carvalho de Melo <acme@redhat.com>
+ *
+ * Based on code from the latency_tracer, that is:
+ *  Copyright (C) 2004-2006 Ingo Molnar
+ *  Copyright (C) 2004 Nadia Yvette Chambers
+ */
+#include <linux/ring_buffer.h>
+#include <generated/utsrelease.h>
+#include <linux/stacktrace.h>
+#include <linux/writeback.h>
+#include <linux/kallsyms.h>
+#include <linux/security.h>
+#include <linux/seq_file.h>
+#include <linux/notifier.h>
+#include <linux/irqflags.h>
+#include <linux/debugfs.h>
+#include <linux/tracefs.h>
+#include <linux/pagemap.h>
+#include <linux/hardirq.h>
+#include <linux/linkage.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <linux/ftrace.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/splice.h>
+#include <linux/kdebug.h>
+#include <linux/string.h>
+#include <linux/mount.h>
+#include <linux/rwsem.h>
+#include <linux/slab.h>
+#include <linux/ctype.h>
+#include <linux/init.h>
+#include <linux/panic_notifier.h>
+#include <linux/poll.h>
+#include <linux/nmi.h>
+#include <linux/fs.h>
+#include <linux/trace.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/rt.h>
+#include <linux/fsnotify.h>
+#include <linux/irq_work.h>
+#include <linux/workqueue.h>
+
+#include "trace.h"
+#include "trace_output.h"
+
+/*
+ * On boot up, the ring buffer is set to the minimum size, so that
+ * we do not waste memory on systems that are not using tracing.
+ */
+bool ring_buffer_expanded;
+
+/*
+ * We need to change this state when a selftest is running.
+ * A selftest will lurk into the ring-buffer to count the
+ * entries inserted during the selftest although some concurrent
+ * insertions into the ring-buffer such as trace_printk could occurred
+ * at the same time, giving false positive or negative results.
+ */
+static bool __read_mostly tracing_selftest_running;
+
+/*
+ * If boot-time tracing including tracers/events via kernel cmdline
+ * is running, we do not want to run SELFTEST.
+ */
+bool __read_mostly tracing_selftest_disabled;
+
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+void __init disable_tracing_selftest(const char *reason)
+{
+	if (!tracing_selftest_disabled) {
+		tracing_selftest_disabled = true;
+		pr_info("Ftrace startup test is disabled due to %s\n", reason);
+	}
+}
+#endif
+
+/* Pipe tracepoints to printk */
+struct trace_iterator *tracepoint_print_iter;
+int tracepoint_printk;
+static bool tracepoint_printk_stop_on_boot __initdata;
+static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
+
+/* For tracers that don't implement custom flags */
+static struct tracer_opt dummy_tracer_opt[] = {
+	{ }
+};
+
+static int
+dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
+{
+	return 0;
+}
+
+/*
+ * To prevent the comm cache from being overwritten when no
+ * tracing is active, only save the comm when a trace event
+ * occurred.
+ */
+static DEFINE_PER_CPU(bool, trace_taskinfo_save);
+
+/*
+ * Kill all tracing for good (never come back).
+ * It is initialized to 1 but will turn to zero if the initialization
+ * of the tracer is successful. But that is the only place that sets
+ * this back to zero.
+ */
+static int tracing_disabled = 1;
+
+cpumask_var_t __read_mostly	tracing_buffer_mask;
+
+/*
+ * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
+ *
+ * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
+ * is set, then ftrace_dump is called. This will output the contents
+ * of the ftrace buffers to the console.  This is very useful for
+ * capturing traces that lead to crashes and outputing it to a
+ * serial console.
+ *
+ * It is default off, but you can enable it with either specifying
+ * "ftrace_dump_on_oops" in the kernel command line, or setting
+ * /proc/sys/kernel/ftrace_dump_on_oops
+ * Set 1 if you want to dump buffers of all CPUs
+ * Set 2 if you want to dump the buffer of the CPU that triggered oops
+ */
+
+enum ftrace_dump_mode ftrace_dump_on_oops;
+
+/* When set, tracing will stop when a WARN*() is hit */
+int __disable_trace_on_warning;
+
+#ifdef CONFIG_TRACE_EVAL_MAP_FILE
+/* Map of enums to their values, for "eval_map" file */
+struct trace_eval_map_head {
+	struct module			*mod;
+	unsigned long			length;
+};
+
+union trace_eval_map_item;
+
+struct trace_eval_map_tail {
+	/*
+	 * "end" is first and points to NULL as it must be different
+	 * than "mod" or "eval_string"
+	 */
+	union trace_eval_map_item	*next;
+	const char			*end;	/* points to NULL */
+};
+
+static DEFINE_MUTEX(trace_eval_mutex);
+
+/*
+ * The trace_eval_maps are saved in an array with two extra elements,
+ * one at the beginning, and one at the end. The beginning item contains
+ * the count of the saved maps (head.length), and the module they
+ * belong to if not built in (head.mod). The ending item contains a
+ * pointer to the next array of saved eval_map items.
+ */
+union trace_eval_map_item {
+	struct trace_eval_map		map;
+	struct trace_eval_map_head	head;
+	struct trace_eval_map_tail	tail;
+};
+
+static union trace_eval_map_item *trace_eval_maps;
+#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
+
+int tracing_set_tracer(struct trace_array *tr, const char *buf);
+static void ftrace_trace_userstack(struct trace_array *tr,
+				   struct trace_buffer *buffer,
+				   unsigned int trace_ctx);
+
+#define MAX_TRACER_SIZE		100
+static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
+static char *default_bootup_tracer;
+
+static bool allocate_snapshot;
+static bool snapshot_at_boot;
+
+static int __init set_cmdline_ftrace(char *str)
+{
+	strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
+	default_bootup_tracer = bootup_tracer_buf;
+	/* We are using ftrace early, expand it */
+	ring_buffer_expanded = true;
+	return 1;
+}
+__setup("ftrace=", set_cmdline_ftrace);
+
+static int __init set_ftrace_dump_on_oops(char *str)
+{
+	if (*str++ != '=' || !*str || !strcmp("1", str)) {
+		ftrace_dump_on_oops = DUMP_ALL;
+		return 1;
+	}
+
+	if (!strcmp("orig_cpu", str) || !strcmp("2", str)) {
+		ftrace_dump_on_oops = DUMP_ORIG;
+                return 1;
+        }
+
+        return 0;
+}
+__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
+
+static int __init stop_trace_on_warning(char *str)
+{
+	if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
+		__disable_trace_on_warning = 1;
+	return 1;
+}
+__setup("traceoff_on_warning", stop_trace_on_warning);
+
+static int __init boot_alloc_snapshot(char *str)
+{
+	allocate_snapshot = true;
+	/* We also need the main ring buffer expanded */
+	ring_buffer_expanded = true;
+	return 1;
+}
+__setup("alloc_snapshot", boot_alloc_snapshot);
+
+
+static int __init boot_snapshot(char *str)
+{
+	snapshot_at_boot = true;
+	boot_alloc_snapshot(str);
+	return 1;
+}
+__setup("ftrace_boot_snapshot", boot_snapshot);
+
+
+static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
+
+static int __init set_trace_boot_options(char *str)
+{
+	strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
+	return 1;
+}
+__setup("trace_options=", set_trace_boot_options);
+
+static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
+static char *trace_boot_clock __initdata;
+
+static int __init set_trace_boot_clock(char *str)
+{
+	strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
+	trace_boot_clock = trace_boot_clock_buf;
+	return 1;
+}
+__setup("trace_clock=", set_trace_boot_clock);
+
+static int __init set_tracepoint_printk(char *str)
+{
+	/* Ignore the "tp_printk_stop_on_boot" param */
+	if (*str == '_')
+		return 0;
+
+	if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
+		tracepoint_printk = 1;
+	return 1;
+}
+__setup("tp_printk", set_tracepoint_printk);
+
+static int __init set_tracepoint_printk_stop(char *str)
+{
+	tracepoint_printk_stop_on_boot = true;
+	return 1;
+}
+__setup("tp_printk_stop_on_boot", set_tracepoint_printk_stop);
+
+unsigned long long ns2usecs(u64 nsec)
+{
+	nsec += 500;
+	do_div(nsec, 1000);
+	return nsec;
+}
+
+static void
+trace_process_export(struct trace_export *export,
+	       struct ring_buffer_event *event, int flag)
+{
+	struct trace_entry *entry;
+	unsigned int size = 0;
+
+	if (export->flags & flag) {
+		entry = ring_buffer_event_data(event);
+		size = ring_buffer_event_length(event);
+		export->write(export, entry, size);
+	}
+}
+
+static DEFINE_MUTEX(ftrace_export_lock);
+
+static struct trace_export __rcu *ftrace_exports_list __read_mostly;
+
+static DEFINE_STATIC_KEY_FALSE(trace_function_exports_enabled);
+static DEFINE_STATIC_KEY_FALSE(trace_event_exports_enabled);
+static DEFINE_STATIC_KEY_FALSE(trace_marker_exports_enabled);
+
+static inline void ftrace_exports_enable(struct trace_export *export)
+{
+	if (export->flags & TRACE_EXPORT_FUNCTION)
+		static_branch_inc(&trace_function_exports_enabled);
+
+	if (export->flags & TRACE_EXPORT_EVENT)
+		static_branch_inc(&trace_event_exports_enabled);
+
+	if (export->flags & TRACE_EXPORT_MARKER)
+		static_branch_inc(&trace_marker_exports_enabled);
+}
+
+static inline void ftrace_exports_disable(struct trace_export *export)
+{
+	if (export->flags & TRACE_EXPORT_FUNCTION)
+		static_branch_dec(&trace_function_exports_enabled);
+
+	if (export->flags & TRACE_EXPORT_EVENT)
+		static_branch_dec(&trace_event_exports_enabled);
+
+	if (export->flags & TRACE_EXPORT_MARKER)
+		static_branch_dec(&trace_marker_exports_enabled);
+}
+
+static void ftrace_exports(struct ring_buffer_event *event, int flag)
+{
+	struct trace_export *export;
+
+	preempt_disable_notrace();
+
+	export = rcu_dereference_raw_check(ftrace_exports_list);
+	while (export) {
+		trace_process_export(export, event, flag);
+		export = rcu_dereference_raw_check(export->next);
+	}
+
+	preempt_enable_notrace();
+}
+
+static inline void
+add_trace_export(struct trace_export **list, struct trace_export *export)
+{
+	rcu_assign_pointer(export->next, *list);
+	/*
+	 * We are entering export into the list but another
+	 * CPU might be walking that list. We need to make sure
+	 * the export->next pointer is valid before another CPU sees
+	 * the export pointer included into the list.
+	 */
+	rcu_assign_pointer(*list, export);
+}
+
+static inline int
+rm_trace_export(struct trace_export **list, struct trace_export *export)
+{
+	struct trace_export **p;
+
+	for (p = list; *p != NULL; p = &(*p)->next)
+		if (*p == export)
+			break;
+
+	if (*p != export)
+		return -1;
+
+	rcu_assign_pointer(*p, (*p)->next);
+
+	return 0;
+}
+
+static inline void
+add_ftrace_export(struct trace_export **list, struct trace_export *export)
+{
+	ftrace_exports_enable(export);
+
+	add_trace_export(list, export);
+}
+
+static inline int
+rm_ftrace_export(struct trace_export **list, struct trace_export *export)
+{
+	int ret;
+
+	ret = rm_trace_export(list, export);
+	ftrace_exports_disable(export);
+
+	return ret;
+}
+
+int register_ftrace_export(struct trace_export *export)
+{
+	if (WARN_ON_ONCE(!export->write))
+		return -1;
+
+	mutex_lock(&ftrace_export_lock);
+
+	add_ftrace_export(&ftrace_exports_list, export);
+
+	mutex_unlock(&ftrace_export_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(register_ftrace_export);
+
+int unregister_ftrace_export(struct trace_export *export)
+{
+	int ret;
+
+	mutex_lock(&ftrace_export_lock);
+
+	ret = rm_ftrace_export(&ftrace_exports_list, export);
+
+	mutex_unlock(&ftrace_export_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(unregister_ftrace_export);
+
+/* trace_flags holds trace_options default values */
+#define TRACE_DEFAULT_FLAGS						\
+	(FUNCTION_DEFAULT_FLAGS |					\
+	 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |			\
+	 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO |		\
+	 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE |			\
+	 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS |			\
+	 TRACE_ITER_HASH_PTR)
+
+/* trace_options that are only supported by global_trace */
+#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK |			\
+	       TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
+
+/* trace_flags that are default zero for instances */
+#define ZEROED_TRACE_FLAGS \
+	(TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK)
+
+/*
+ * The global_trace is the descriptor that holds the top-level tracing
+ * buffers for the live tracing.
+ */
+static struct trace_array global_trace = {
+	.trace_flags = TRACE_DEFAULT_FLAGS,
+};
+
+LIST_HEAD(ftrace_trace_arrays);
+
+int trace_array_get(struct trace_array *this_tr)
+{
+	struct trace_array *tr;
+	int ret = -ENODEV;
+
+	mutex_lock(&trace_types_lock);
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (tr == this_tr) {
+			tr->ref++;
+			ret = 0;
+			break;
+		}
+	}
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+static void __trace_array_put(struct trace_array *this_tr)
+{
+	WARN_ON(!this_tr->ref);
+	this_tr->ref--;
+}
+
+/**
+ * trace_array_put - Decrement the reference counter for this trace array.
+ * @this_tr : pointer to the trace array
+ *
+ * NOTE: Use this when we no longer need the trace array returned by
+ * trace_array_get_by_name(). This ensures the trace array can be later
+ * destroyed.
+ *
+ */
+void trace_array_put(struct trace_array *this_tr)
+{
+	if (!this_tr)
+		return;
+
+	mutex_lock(&trace_types_lock);
+	__trace_array_put(this_tr);
+	mutex_unlock(&trace_types_lock);
+}
+EXPORT_SYMBOL_GPL(trace_array_put);
+
+int tracing_check_open_get_tr(struct trace_array *tr)
+{
+	int ret;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	if (tracing_disabled)
+		return -ENODEV;
+
+	if (tr && trace_array_get(tr) < 0)
+		return -ENODEV;
+
+	return 0;
+}
+
+int call_filter_check_discard(struct trace_event_call *call, void *rec,
+			      struct trace_buffer *buffer,
+			      struct ring_buffer_event *event)
+{
+	if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
+	    !filter_match_preds(call->filter, rec)) {
+		__trace_event_discard_commit(buffer, event);
+		return 1;
+	}
+
+	return 0;
+}
+
+/**
+ * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
+ * @filtered_pids: The list of pids to check
+ * @search_pid: The PID to find in @filtered_pids
+ *
+ * Returns true if @search_pid is found in @filtered_pids, and false otherwise.
+ */
+bool
+trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
+{
+	return trace_pid_list_is_set(filtered_pids, search_pid);
+}
+
+/**
+ * trace_ignore_this_task - should a task be ignored for tracing
+ * @filtered_pids: The list of pids to check
+ * @filtered_no_pids: The list of pids not to be traced
+ * @task: The task that should be ignored if not filtered
+ *
+ * Checks if @task should be traced or not from @filtered_pids.
+ * Returns true if @task should *NOT* be traced.
+ * Returns false if @task should be traced.
+ */
+bool
+trace_ignore_this_task(struct trace_pid_list *filtered_pids,
+		       struct trace_pid_list *filtered_no_pids,
+		       struct task_struct *task)
+{
+	/*
+	 * If filtered_no_pids is not empty, and the task's pid is listed
+	 * in filtered_no_pids, then return true.
+	 * Otherwise, if filtered_pids is empty, that means we can
+	 * trace all tasks. If it has content, then only trace pids
+	 * within filtered_pids.
+	 */
+
+	return (filtered_pids &&
+		!trace_find_filtered_pid(filtered_pids, task->pid)) ||
+		(filtered_no_pids &&
+		 trace_find_filtered_pid(filtered_no_pids, task->pid));
+}
+
+/**
+ * trace_filter_add_remove_task - Add or remove a task from a pid_list
+ * @pid_list: The list to modify
+ * @self: The current task for fork or NULL for exit
+ * @task: The task to add or remove
+ *
+ * If adding a task, if @self is defined, the task is only added if @self
+ * is also included in @pid_list. This happens on fork and tasks should
+ * only be added when the parent is listed. If @self is NULL, then the
+ * @task pid will be removed from the list, which would happen on exit
+ * of a task.
+ */
+void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
+				  struct task_struct *self,
+				  struct task_struct *task)
+{
+	if (!pid_list)
+		return;
+
+	/* For forks, we only add if the forking task is listed */
+	if (self) {
+		if (!trace_find_filtered_pid(pid_list, self->pid))
+			return;
+	}
+
+	/* "self" is set for forks, and NULL for exits */
+	if (self)
+		trace_pid_list_set(pid_list, task->pid);
+	else
+		trace_pid_list_clear(pid_list, task->pid);
+}
+
+/**
+ * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
+ * @pid_list: The pid list to show
+ * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
+ * @pos: The position of the file
+ *
+ * This is used by the seq_file "next" operation to iterate the pids
+ * listed in a trace_pid_list structure.
+ *
+ * Returns the pid+1 as we want to display pid of zero, but NULL would
+ * stop the iteration.
+ */
+void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
+{
+	long pid = (unsigned long)v;
+	unsigned int next;
+
+	(*pos)++;
+
+	/* pid already is +1 of the actual previous bit */
+	if (trace_pid_list_next(pid_list, pid, &next) < 0)
+		return NULL;
+
+	pid = next;
+
+	/* Return pid + 1 to allow zero to be represented */
+	return (void *)(pid + 1);
+}
+
+/**
+ * trace_pid_start - Used for seq_file to start reading pid lists
+ * @pid_list: The pid list to show
+ * @pos: The position of the file
+ *
+ * This is used by seq_file "start" operation to start the iteration
+ * of listing pids.
+ *
+ * Returns the pid+1 as we want to display pid of zero, but NULL would
+ * stop the iteration.
+ */
+void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
+{
+	unsigned long pid;
+	unsigned int first;
+	loff_t l = 0;
+
+	if (trace_pid_list_first(pid_list, &first) < 0)
+		return NULL;
+
+	pid = first;
+
+	/* Return pid + 1 so that zero can be the exit value */
+	for (pid++; pid && l < *pos;
+	     pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
+		;
+	return (void *)pid;
+}
+
+/**
+ * trace_pid_show - show the current pid in seq_file processing
+ * @m: The seq_file structure to write into
+ * @v: A void pointer of the pid (+1) value to display
+ *
+ * Can be directly used by seq_file operations to display the current
+ * pid value.
+ */
+int trace_pid_show(struct seq_file *m, void *v)
+{
+	unsigned long pid = (unsigned long)v - 1;
+
+	seq_printf(m, "%lu\n", pid);
+	return 0;
+}
+
+/* 128 should be much more than enough */
+#define PID_BUF_SIZE		127
+
+int trace_pid_write(struct trace_pid_list *filtered_pids,
+		    struct trace_pid_list **new_pid_list,
+		    const char __user *ubuf, size_t cnt)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_parser parser;
+	unsigned long val;
+	int nr_pids = 0;
+	ssize_t read = 0;
+	ssize_t ret;
+	loff_t pos;
+	pid_t pid;
+
+	if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
+		return -ENOMEM;
+
+	/*
+	 * Always recreate a new array. The write is an all or nothing
+	 * operation. Always create a new array when adding new pids by
+	 * the user. If the operation fails, then the current list is
+	 * not modified.
+	 */
+	pid_list = trace_pid_list_alloc();
+	if (!pid_list) {
+		trace_parser_put(&parser);
+		return -ENOMEM;
+	}
+
+	if (filtered_pids) {
+		/* copy the current bits to the new max */
+		ret = trace_pid_list_first(filtered_pids, &pid);
+		while (!ret) {
+			trace_pid_list_set(pid_list, pid);
+			ret = trace_pid_list_next(filtered_pids, pid + 1, &pid);
+			nr_pids++;
+		}
+	}
+
+	ret = 0;
+	while (cnt > 0) {
+
+		pos = 0;
+
+		ret = trace_get_user(&parser, ubuf, cnt, &pos);
+		if (ret < 0)
+			break;
+
+		read += ret;
+		ubuf += ret;
+		cnt -= ret;
+
+		if (!trace_parser_loaded(&parser))
+			break;
+
+		ret = -EINVAL;
+		if (kstrtoul(parser.buffer, 0, &val))
+			break;
+
+		pid = (pid_t)val;
+
+		if (trace_pid_list_set(pid_list, pid) < 0) {
+			ret = -1;
+			break;
+		}
+		nr_pids++;
+
+		trace_parser_clear(&parser);
+		ret = 0;
+	}
+	trace_parser_put(&parser);
+
+	if (ret < 0) {
+		trace_pid_list_free(pid_list);
+		return ret;
+	}
+
+	if (!nr_pids) {
+		/* Cleared the list of pids */
+		trace_pid_list_free(pid_list);
+		pid_list = NULL;
+	}
+
+	*new_pid_list = pid_list;
+
+	return read;
+}
+
+static u64 buffer_ftrace_now(struct array_buffer *buf, int cpu)
+{
+	u64 ts;
+
+	/* Early boot up does not have a buffer yet */
+	if (!buf->buffer)
+		return trace_clock_local();
+
+	ts = ring_buffer_time_stamp(buf->buffer);
+	ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
+
+	return ts;
+}
+
+u64 ftrace_now(int cpu)
+{
+	return buffer_ftrace_now(&global_trace.array_buffer, cpu);
+}
+
+/**
+ * tracing_is_enabled - Show if global_trace has been enabled
+ *
+ * Shows if the global trace has been enabled or not. It uses the
+ * mirror flag "buffer_disabled" to be used in fast paths such as for
+ * the irqsoff tracer. But it may be inaccurate due to races. If you
+ * need to know the accurate state, use tracing_is_on() which is a little
+ * slower, but accurate.
+ */
+int tracing_is_enabled(void)
+{
+	/*
+	 * For quick access (irqsoff uses this in fast path), just
+	 * return the mirror variable of the state of the ring buffer.
+	 * It's a little racy, but we don't really care.
+	 */
+	smp_rmb();
+	return !global_trace.buffer_disabled;
+}
+
+/*
+ * trace_buf_size is the size in bytes that is allocated
+ * for a buffer. Note, the number of bytes is always rounded
+ * to page size.
+ *
+ * This number is purposely set to a low number of 16384.
+ * If the dump on oops happens, it will be much appreciated
+ * to not have to wait for all that output. Anyway this can be
+ * boot time and run time configurable.
+ */
+#define TRACE_BUF_SIZE_DEFAULT	1441792UL /* 16384 * 88 (sizeof(entry)) */
+
+static unsigned long		trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
+
+/* trace_types holds a link list of available tracers. */
+static struct tracer		*trace_types __read_mostly;
+
+/*
+ * trace_types_lock is used to protect the trace_types list.
+ */
+DEFINE_MUTEX(trace_types_lock);
+
+/*
+ * serialize the access of the ring buffer
+ *
+ * ring buffer serializes readers, but it is low level protection.
+ * The validity of the events (which returns by ring_buffer_peek() ..etc)
+ * are not protected by ring buffer.
+ *
+ * The content of events may become garbage if we allow other process consumes
+ * these events concurrently:
+ *   A) the page of the consumed events may become a normal page
+ *      (not reader page) in ring buffer, and this page will be rewritten
+ *      by events producer.
+ *   B) The page of the consumed events may become a page for splice_read,
+ *      and this page will be returned to system.
+ *
+ * These primitives allow multi process access to different cpu ring buffer
+ * concurrently.
+ *
+ * These primitives don't distinguish read-only and read-consume access.
+ * Multi read-only access are also serialized.
+ */
+
+#ifdef CONFIG_SMP
+static DECLARE_RWSEM(all_cpu_access_lock);
+static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
+
+static inline void trace_access_lock(int cpu)
+{
+	if (cpu == RING_BUFFER_ALL_CPUS) {
+		/* gain it for accessing the whole ring buffer. */
+		down_write(&all_cpu_access_lock);
+	} else {
+		/* gain it for accessing a cpu ring buffer. */
+
+		/* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
+		down_read(&all_cpu_access_lock);
+
+		/* Secondly block other access to this @cpu ring buffer. */
+		mutex_lock(&per_cpu(cpu_access_lock, cpu));
+	}
+}
+
+static inline void trace_access_unlock(int cpu)
+{
+	if (cpu == RING_BUFFER_ALL_CPUS) {
+		up_write(&all_cpu_access_lock);
+	} else {
+		mutex_unlock(&per_cpu(cpu_access_lock, cpu));
+		up_read(&all_cpu_access_lock);
+	}
+}
+
+static inline void trace_access_lock_init(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		mutex_init(&per_cpu(cpu_access_lock, cpu));
+}
+
+#else
+
+static DEFINE_MUTEX(access_lock);
+
+static inline void trace_access_lock(int cpu)
+{
+	(void)cpu;
+	mutex_lock(&access_lock);
+}
+
+static inline void trace_access_unlock(int cpu)
+{
+	(void)cpu;
+	mutex_unlock(&access_lock);
+}
+
+static inline void trace_access_lock_init(void)
+{
+}
+
+#endif
+
+#ifdef CONFIG_STACKTRACE
+static void __ftrace_trace_stack(struct trace_buffer *buffer,
+				 unsigned int trace_ctx,
+				 int skip, struct pt_regs *regs);
+static inline void ftrace_trace_stack(struct trace_array *tr,
+				      struct trace_buffer *buffer,
+				      unsigned int trace_ctx,
+				      int skip, struct pt_regs *regs);
+
+#else
+static inline void __ftrace_trace_stack(struct trace_buffer *buffer,
+					unsigned int trace_ctx,
+					int skip, struct pt_regs *regs)
+{
+}
+static inline void ftrace_trace_stack(struct trace_array *tr,
+				      struct trace_buffer *buffer,
+				      unsigned long trace_ctx,
+				      int skip, struct pt_regs *regs)
+{
+}
+
+#endif
+
+static __always_inline void
+trace_event_setup(struct ring_buffer_event *event,
+		  int type, unsigned int trace_ctx)
+{
+	struct trace_entry *ent = ring_buffer_event_data(event);
+
+	tracing_generic_entry_update(ent, type, trace_ctx);
+}
+
+static __always_inline struct ring_buffer_event *
+__trace_buffer_lock_reserve(struct trace_buffer *buffer,
+			  int type,
+			  unsigned long len,
+			  unsigned int trace_ctx)
+{
+	struct ring_buffer_event *event;
+
+	event = ring_buffer_lock_reserve(buffer, len);
+	if (event != NULL)
+		trace_event_setup(event, type, trace_ctx);
+
+	return event;
+}
+
+void tracer_tracing_on(struct trace_array *tr)
+{
+	if (tr->array_buffer.buffer)
+		ring_buffer_record_on(tr->array_buffer.buffer);
+	/*
+	 * This flag is looked at when buffers haven't been allocated
+	 * yet, or by some tracers (like irqsoff), that just want to
+	 * know if the ring buffer has been disabled, but it can handle
+	 * races of where it gets disabled but we still do a record.
+	 * As the check is in the fast path of the tracers, it is more
+	 * important to be fast than accurate.
+	 */
+	tr->buffer_disabled = 0;
+	/* Make the flag seen by readers */
+	smp_wmb();
+}
+
+/**
+ * tracing_on - enable tracing buffers
+ *
+ * This function enables tracing buffers that may have been
+ * disabled with tracing_off.
+ */
+void tracing_on(void)
+{
+	tracer_tracing_on(&global_trace);
+}
+EXPORT_SYMBOL_GPL(tracing_on);
+
+
+static __always_inline void
+__buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *event)
+{
+	__this_cpu_write(trace_taskinfo_save, true);
+
+	/* If this is the temp buffer, we need to commit fully */
+	if (this_cpu_read(trace_buffered_event) == event) {
+		/* Length is in event->array[0] */
+		ring_buffer_write(buffer, event->array[0], &event->array[1]);
+		/* Release the temp buffer */
+		this_cpu_dec(trace_buffered_event_cnt);
+		/* ring_buffer_unlock_commit() enables preemption */
+		preempt_enable_notrace();
+	} else
+		ring_buffer_unlock_commit(buffer, event);
+}
+
+int __trace_array_puts(struct trace_array *tr, unsigned long ip,
+		       const char *str, int size)
+{
+	struct ring_buffer_event *event;
+	struct trace_buffer *buffer;
+	struct print_entry *entry;
+	unsigned int trace_ctx;
+	int alloc;
+
+	if (!(tr->trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	if (unlikely(tracing_selftest_running || tracing_disabled))
+		return 0;
+
+	alloc = sizeof(*entry) + size + 2; /* possible \n added */
+
+	trace_ctx = tracing_gen_ctx();
+	buffer = tr->array_buffer.buffer;
+	ring_buffer_nest_start(buffer);
+	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
+					    trace_ctx);
+	if (!event) {
+		size = 0;
+		goto out;
+	}
+
+	entry = ring_buffer_event_data(event);
+	entry->ip = ip;
+
+	memcpy(&entry->buf, str, size);
+
+	/* Add a newline if necessary */
+	if (entry->buf[size - 1] != '\n') {
+		entry->buf[size] = '\n';
+		entry->buf[size + 1] = '\0';
+	} else
+		entry->buf[size] = '\0';
+
+	__buffer_unlock_commit(buffer, event);
+	ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
+ out:
+	ring_buffer_nest_end(buffer);
+	return size;
+}
+EXPORT_SYMBOL_GPL(__trace_array_puts);
+
+/**
+ * __trace_puts - write a constant string into the trace buffer.
+ * @ip:	   The address of the caller
+ * @str:   The constant string to write
+ * @size:  The size of the string.
+ */
+int __trace_puts(unsigned long ip, const char *str, int size)
+{
+	return __trace_array_puts(&global_trace, ip, str, size);
+}
+EXPORT_SYMBOL_GPL(__trace_puts);
+
+/**
+ * __trace_bputs - write the pointer to a constant string into trace buffer
+ * @ip:	   The address of the caller
+ * @str:   The constant string to write to the buffer to
+ */
+int __trace_bputs(unsigned long ip, const char *str)
+{
+	struct ring_buffer_event *event;
+	struct trace_buffer *buffer;
+	struct bputs_entry *entry;
+	unsigned int trace_ctx;
+	int size = sizeof(struct bputs_entry);
+	int ret = 0;
+
+	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	if (unlikely(tracing_selftest_running || tracing_disabled))
+		return 0;
+
+	trace_ctx = tracing_gen_ctx();
+	buffer = global_trace.array_buffer.buffer;
+
+	ring_buffer_nest_start(buffer);
+	event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
+					    trace_ctx);
+	if (!event)
+		goto out;
+
+	entry = ring_buffer_event_data(event);
+	entry->ip			= ip;
+	entry->str			= str;
+
+	__buffer_unlock_commit(buffer, event);
+	ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);
+
+	ret = 1;
+ out:
+	ring_buffer_nest_end(buffer);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__trace_bputs);
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+static void tracing_snapshot_instance_cond(struct trace_array *tr,
+					   void *cond_data)
+{
+	struct tracer *tracer = tr->current_trace;
+	unsigned long flags;
+
+	if (in_nmi()) {
+		trace_array_puts(tr, "*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
+		trace_array_puts(tr, "*** snapshot is being ignored        ***\n");
+		return;
+	}
+
+	if (!tr->allocated_snapshot) {
+		trace_array_puts(tr, "*** SNAPSHOT NOT ALLOCATED ***\n");
+		trace_array_puts(tr, "*** stopping trace here!   ***\n");
+		tracer_tracing_off(tr);
+		return;
+	}
+
+	/* Note, snapshot can not be used when the tracer uses it */
+	if (tracer->use_max_tr) {
+		trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n");
+		trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n");
+		return;
+	}
+
+	local_irq_save(flags);
+	update_max_tr(tr, current, smp_processor_id(), cond_data);
+	local_irq_restore(flags);
+}
+
+void tracing_snapshot_instance(struct trace_array *tr)
+{
+	tracing_snapshot_instance_cond(tr, NULL);
+}
+
+/**
+ * tracing_snapshot - take a snapshot of the current buffer.
+ *
+ * This causes a swap between the snapshot buffer and the current live
+ * tracing buffer. You can use this to take snapshots of the live
+ * trace when some condition is triggered, but continue to trace.
+ *
+ * Note, make sure to allocate the snapshot with either
+ * a tracing_snapshot_alloc(), or by doing it manually
+ * with: echo 1 > /sys/kernel/debug/tracing/snapshot
+ *
+ * If the snapshot buffer is not allocated, it will stop tracing.
+ * Basically making a permanent snapshot.
+ */
+void tracing_snapshot(void)
+{
+	struct trace_array *tr = &global_trace;
+
+	tracing_snapshot_instance(tr);
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot);
+
+/**
+ * tracing_snapshot_cond - conditionally take a snapshot of the current buffer.
+ * @tr:		The tracing instance to snapshot
+ * @cond_data:	The data to be tested conditionally, and possibly saved
+ *
+ * This is the same as tracing_snapshot() except that the snapshot is
+ * conditional - the snapshot will only happen if the
+ * cond_snapshot.update() implementation receiving the cond_data
+ * returns true, which means that the trace array's cond_snapshot
+ * update() operation used the cond_data to determine whether the
+ * snapshot should be taken, and if it was, presumably saved it along
+ * with the snapshot.
+ */
+void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
+{
+	tracing_snapshot_instance_cond(tr, cond_data);
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
+
+/**
+ * tracing_cond_snapshot_data - get the user data associated with a snapshot
+ * @tr:		The tracing instance
+ *
+ * When the user enables a conditional snapshot using
+ * tracing_snapshot_cond_enable(), the user-defined cond_data is saved
+ * with the snapshot.  This accessor is used to retrieve it.
+ *
+ * Should not be called from cond_snapshot.update(), since it takes
+ * the tr->max_lock lock, which the code calling
+ * cond_snapshot.update() has already done.
+ *
+ * Returns the cond_data associated with the trace array's snapshot.
+ */
+void *tracing_cond_snapshot_data(struct trace_array *tr)
+{
+	void *cond_data = NULL;
+
+	local_irq_disable();
+	arch_spin_lock(&tr->max_lock);
+
+	if (tr->cond_snapshot)
+		cond_data = tr->cond_snapshot->cond_data;
+
+	arch_spin_unlock(&tr->max_lock);
+	local_irq_enable();
+
+	return cond_data;
+}
+EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
+
+static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
+					struct array_buffer *size_buf, int cpu_id);
+static void set_buffer_entries(struct array_buffer *buf, unsigned long val);
+
+int tracing_alloc_snapshot_instance(struct trace_array *tr)
+{
+	int ret;
+
+	if (!tr->allocated_snapshot) {
+
+		/* allocate spare buffer */
+		ret = resize_buffer_duplicate_size(&tr->max_buffer,
+				   &tr->array_buffer, RING_BUFFER_ALL_CPUS);
+		if (ret < 0)
+			return ret;
+
+		tr->allocated_snapshot = true;
+	}
+
+	return 0;
+}
+
+static void free_snapshot(struct trace_array *tr)
+{
+	/*
+	 * We don't free the ring buffer. instead, resize it because
+	 * The max_tr ring buffer has some state (e.g. ring->clock) and
+	 * we want preserve it.
+	 */
+	ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
+	set_buffer_entries(&tr->max_buffer, 1);
+	tracing_reset_online_cpus(&tr->max_buffer);
+	tr->allocated_snapshot = false;
+}
+
+/**
+ * tracing_alloc_snapshot - allocate snapshot buffer.
+ *
+ * This only allocates the snapshot buffer if it isn't already
+ * allocated - it doesn't also take a snapshot.
+ *
+ * This is meant to be used in cases where the snapshot buffer needs
+ * to be set up for events that can't sleep but need to be able to
+ * trigger a snapshot.
+ */
+int tracing_alloc_snapshot(void)
+{
+	struct trace_array *tr = &global_trace;
+	int ret;
+
+	ret = tracing_alloc_snapshot_instance(tr);
+	WARN_ON(ret < 0);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
+
+/**
+ * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
+ *
+ * This is similar to tracing_snapshot(), but it will allocate the
+ * snapshot buffer if it isn't already allocated. Use this only
+ * where it is safe to sleep, as the allocation may sleep.
+ *
+ * This causes a swap between the snapshot buffer and the current live
+ * tracing buffer. You can use this to take snapshots of the live
+ * trace when some condition is triggered, but continue to trace.
+ */
+void tracing_snapshot_alloc(void)
+{
+	int ret;
+
+	ret = tracing_alloc_snapshot();
+	if (ret < 0)
+		return;
+
+	tracing_snapshot();
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
+
+/**
+ * tracing_snapshot_cond_enable - enable conditional snapshot for an instance
+ * @tr:		The tracing instance
+ * @cond_data:	User data to associate with the snapshot
+ * @update:	Implementation of the cond_snapshot update function
+ *
+ * Check whether the conditional snapshot for the given instance has
+ * already been enabled, or if the current tracer is already using a
+ * snapshot; if so, return -EBUSY, else create a cond_snapshot and
+ * save the cond_data and update function inside.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
+				 cond_update_fn_t update)
+{
+	struct cond_snapshot *cond_snapshot;
+	int ret = 0;
+
+	cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
+	if (!cond_snapshot)
+		return -ENOMEM;
+
+	cond_snapshot->cond_data = cond_data;
+	cond_snapshot->update = update;
+
+	mutex_lock(&trace_types_lock);
+
+	ret = tracing_alloc_snapshot_instance(tr);
+	if (ret)
+		goto fail_unlock;
+
+	if (tr->current_trace->use_max_tr) {
+		ret = -EBUSY;
+		goto fail_unlock;
+	}
+
+	/*
+	 * The cond_snapshot can only change to NULL without the
+	 * trace_types_lock. We don't care if we race with it going
+	 * to NULL, but we want to make sure that it's not set to
+	 * something other than NULL when we get here, which we can
+	 * do safely with only holding the trace_types_lock and not
+	 * having to take the max_lock.
+	 */
+	if (tr->cond_snapshot) {
+		ret = -EBUSY;
+		goto fail_unlock;
+	}
+
+	local_irq_disable();
+	arch_spin_lock(&tr->max_lock);
+	tr->cond_snapshot = cond_snapshot;
+	arch_spin_unlock(&tr->max_lock);
+	local_irq_enable();
+
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+
+ fail_unlock:
+	mutex_unlock(&trace_types_lock);
+	kfree(cond_snapshot);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
+
+/**
+ * tracing_snapshot_cond_disable - disable conditional snapshot for an instance
+ * @tr:		The tracing instance
+ *
+ * Check whether the conditional snapshot for the given instance is
+ * enabled; if so, free the cond_snapshot associated with it,
+ * otherwise return -EINVAL.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int tracing_snapshot_cond_disable(struct trace_array *tr)
+{
+	int ret = 0;
+
+	local_irq_disable();
+	arch_spin_lock(&tr->max_lock);
+
+	if (!tr->cond_snapshot)
+		ret = -EINVAL;
+	else {
+		kfree(tr->cond_snapshot);
+		tr->cond_snapshot = NULL;
+	}
+
+	arch_spin_unlock(&tr->max_lock);
+	local_irq_enable();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
+#else
+void tracing_snapshot(void)
+{
+	WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot);
+void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
+{
+	WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used");
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
+int tracing_alloc_snapshot(void)
+{
+	WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
+void tracing_snapshot_alloc(void)
+{
+	/* Give warning */
+	tracing_snapshot();
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
+void *tracing_cond_snapshot_data(struct trace_array *tr)
+{
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
+int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update)
+{
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
+int tracing_snapshot_cond_disable(struct trace_array *tr)
+{
+	return false;
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
+#define free_snapshot(tr)	do { } while (0)
+#endif /* CONFIG_TRACER_SNAPSHOT */
+
+void tracer_tracing_off(struct trace_array *tr)
+{
+	if (tr->array_buffer.buffer)
+		ring_buffer_record_off(tr->array_buffer.buffer);
+	/*
+	 * This flag is looked at when buffers haven't been allocated
+	 * yet, or by some tracers (like irqsoff), that just want to
+	 * know if the ring buffer has been disabled, but it can handle
+	 * races of where it gets disabled but we still do a record.
+	 * As the check is in the fast path of the tracers, it is more
+	 * important to be fast than accurate.
+	 */
+	tr->buffer_disabled = 1;
+	/* Make the flag seen by readers */
+	smp_wmb();
+}
+
+/**
+ * tracing_off - turn off tracing buffers
+ *
+ * This function stops the tracing buffers from recording data.
+ * It does not disable any overhead the tracers themselves may
+ * be causing. This function simply causes all recording to
+ * the ring buffers to fail.
+ */
+void tracing_off(void)
+{
+	tracer_tracing_off(&global_trace);
+}
+EXPORT_SYMBOL_GPL(tracing_off);
+
+void disable_trace_on_warning(void)
+{
+	if (__disable_trace_on_warning) {
+		trace_array_printk_buf(global_trace.array_buffer.buffer, _THIS_IP_,
+			"Disabling tracing due to warning\n");
+		tracing_off();
+	}
+}
+
+/**
+ * tracer_tracing_is_on - show real state of ring buffer enabled
+ * @tr : the trace array to know if ring buffer is enabled
+ *
+ * Shows real state of the ring buffer if it is enabled or not.
+ */
+bool tracer_tracing_is_on(struct trace_array *tr)
+{
+	if (tr->array_buffer.buffer)
+		return ring_buffer_record_is_on(tr->array_buffer.buffer);
+	return !tr->buffer_disabled;
+}
+
+/**
+ * tracing_is_on - show state of ring buffers enabled
+ */
+int tracing_is_on(void)
+{
+	return tracer_tracing_is_on(&global_trace);
+}
+EXPORT_SYMBOL_GPL(tracing_is_on);
+
+static int __init set_buf_size(char *str)
+{
+	unsigned long buf_size;
+
+	if (!str)
+		return 0;
+	buf_size = memparse(str, &str);
+	/*
+	 * nr_entries can not be zero and the startup
+	 * tests require some buffer space. Therefore
+	 * ensure we have at least 4096 bytes of buffer.
+	 */
+	trace_buf_size = max(4096UL, buf_size);
+	return 1;
+}
+__setup("trace_buf_size=", set_buf_size);
+
+static int __init set_tracing_thresh(char *str)
+{
+	unsigned long threshold;
+	int ret;
+
+	if (!str)
+		return 0;
+	ret = kstrtoul(str, 0, &threshold);
+	if (ret < 0)
+		return 0;
+	tracing_thresh = threshold * 1000;
+	return 1;
+}
+__setup("tracing_thresh=", set_tracing_thresh);
+
+unsigned long nsecs_to_usecs(unsigned long nsecs)
+{
+	return nsecs / 1000;
+}
+
+/*
+ * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
+ * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that
+ * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
+ * of strings in the order that the evals (enum) were defined.
+ */
+#undef C
+#define C(a, b) b
+
+/* These must match the bit positions in trace_iterator_flags */
+static const char *trace_options[] = {
+	TRACE_FLAGS
+	NULL
+};
+
+static struct {
+	u64 (*func)(void);
+	const char *name;
+	int in_ns;		/* is this clock in nanoseconds? */
+} trace_clocks[] = {
+	{ trace_clock_local,		"local",	1 },
+	{ trace_clock_global,		"global",	1 },
+	{ trace_clock_counter,		"counter",	0 },
+	{ trace_clock_jiffies,		"uptime",	0 },
+	{ trace_clock,			"perf",		1 },
+	{ ktime_get_mono_fast_ns,	"mono",		1 },
+	{ ktime_get_raw_fast_ns,	"mono_raw",	1 },
+	{ ktime_get_boot_fast_ns,	"boot",		1 },
+	{ ktime_get_tai_fast_ns,	"tai",		1 },
+	ARCH_TRACE_CLOCKS
+};
+
+bool trace_clock_in_ns(struct trace_array *tr)
+{
+	if (trace_clocks[tr->clock_id].in_ns)
+		return true;
+
+	return false;
+}
+
+/*
+ * trace_parser_get_init - gets the buffer for trace parser
+ */
+int trace_parser_get_init(struct trace_parser *parser, int size)
+{
+	memset(parser, 0, sizeof(*parser));
+
+	parser->buffer = kmalloc(size, GFP_KERNEL);
+	if (!parser->buffer)
+		return 1;
+
+	parser->size = size;
+	return 0;
+}
+
+/*
+ * trace_parser_put - frees the buffer for trace parser
+ */
+void trace_parser_put(struct trace_parser *parser)
+{
+	kfree(parser->buffer);
+	parser->buffer = NULL;
+}
+
+/*
+ * trace_get_user - reads the user input string separated by  space
+ * (matched by isspace(ch))
+ *
+ * For each string found the 'struct trace_parser' is updated,
+ * and the function returns.
+ *
+ * Returns number of bytes read.
+ *
+ * See kernel/trace/trace.h for 'struct trace_parser' details.
+ */
+int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
+	size_t cnt, loff_t *ppos)
+{
+	char ch;
+	size_t read = 0;
+	ssize_t ret;
+
+	if (!*ppos)
+		trace_parser_clear(parser);
+
+	ret = get_user(ch, ubuf++);
+	if (ret)
+		goto out;
+
+	read++;
+	cnt--;
+
+	/*
+	 * The parser is not finished with the last write,
+	 * continue reading the user input without skipping spaces.
+	 */
+	if (!parser->cont) {
+		/* skip white space */
+		while (cnt && isspace(ch)) {
+			ret = get_user(ch, ubuf++);
+			if (ret)
+				goto out;
+			read++;
+			cnt--;
+		}
+
+		parser->idx = 0;
+
+		/* only spaces were written */
+		if (isspace(ch) || !ch) {
+			*ppos += read;
+			ret = read;
+			goto out;
+		}
+	}
+
+	/* read the non-space input */
+	while (cnt && !isspace(ch) && ch) {
+		if (parser->idx < parser->size - 1)
+			parser->buffer[parser->idx++] = ch;
+		else {
+			ret = -EINVAL;
+			goto out;
+		}
+		ret = get_user(ch, ubuf++);
+		if (ret)
+			goto out;
+		read++;
+		cnt--;
+	}
+
+	/* We either got finished input or we have to wait for another call. */
+	if (isspace(ch) || !ch) {
+		parser->buffer[parser->idx] = 0;
+		parser->cont = false;
+	} else if (parser->idx < parser->size - 1) {
+		parser->cont = true;
+		parser->buffer[parser->idx++] = ch;
+		/* Make sure the parsed string always terminates with '\0'. */
+		parser->buffer[parser->idx] = 0;
+	} else {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	*ppos += read;
+	ret = read;
+
+out:
+	return ret;
+}
+
+/* TODO add a seq_buf_to_buffer() */
+static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
+{
+	int len;
+
+	if (trace_seq_used(s) <= s->seq.readpos)
+		return -EBUSY;
+
+	len = trace_seq_used(s) - s->seq.readpos;
+	if (cnt > len)
+		cnt = len;
+	memcpy(buf, s->buffer + s->seq.readpos, cnt);
+
+	s->seq.readpos += cnt;
+	return cnt;
+}
+
+unsigned long __read_mostly	tracing_thresh;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+static const struct file_operations tracing_max_lat_fops;
+
+#ifdef LATENCY_FS_NOTIFY
+
+static struct workqueue_struct *fsnotify_wq;
+
+static void latency_fsnotify_workfn(struct work_struct *work)
+{
+	struct trace_array *tr = container_of(work, struct trace_array,
+					      fsnotify_work);
+	fsnotify_inode(tr->d_max_latency->d_inode, FS_MODIFY);
+}
+
+static void latency_fsnotify_workfn_irq(struct irq_work *iwork)
+{
+	struct trace_array *tr = container_of(iwork, struct trace_array,
+					      fsnotify_irqwork);
+	queue_work(fsnotify_wq, &tr->fsnotify_work);
+}
+
+static void trace_create_maxlat_file(struct trace_array *tr,
+				     struct dentry *d_tracer)
+{
+	INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
+	init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
+	tr->d_max_latency = trace_create_file("tracing_max_latency",
+					      TRACE_MODE_WRITE,
+					      d_tracer, tr,
+					      &tracing_max_lat_fops);
+}
+
+__init static int latency_fsnotify_init(void)
+{
+	fsnotify_wq = alloc_workqueue("tr_max_lat_wq",
+				      WQ_UNBOUND | WQ_HIGHPRI, 0);
+	if (!fsnotify_wq) {
+		pr_err("Unable to allocate tr_max_lat_wq\n");
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+late_initcall_sync(latency_fsnotify_init);
+
+void latency_fsnotify(struct trace_array *tr)
+{
+	if (!fsnotify_wq)
+		return;
+	/*
+	 * We cannot call queue_work(&tr->fsnotify_work) from here because it's
+	 * possible that we are called from __schedule() or do_idle(), which
+	 * could cause a deadlock.
+	 */
+	irq_work_queue(&tr->fsnotify_irqwork);
+}
+
+#else /* !LATENCY_FS_NOTIFY */
+
+#define trace_create_maxlat_file(tr, d_tracer)				\
+	trace_create_file("tracing_max_latency", TRACE_MODE_WRITE,	\
+			  d_tracer, tr, &tracing_max_lat_fops)
+
+#endif
+
+/*
+ * Copy the new maximum trace into the separate maximum-trace
+ * structure. (this way the maximum trace is permanently saved,
+ * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
+ */
+static void
+__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
+{
+	struct array_buffer *trace_buf = &tr->array_buffer;
+	struct array_buffer *max_buf = &tr->max_buffer;
+	struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
+	struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
+
+	max_buf->cpu = cpu;
+	max_buf->time_start = data->preempt_timestamp;
+
+	max_data->saved_latency = tr->max_latency;
+	max_data->critical_start = data->critical_start;
+	max_data->critical_end = data->critical_end;
+
+	strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
+	max_data->pid = tsk->pid;
+	/*
+	 * If tsk == current, then use current_uid(), as that does not use
+	 * RCU. The irq tracer can be called out of RCU scope.
+	 */
+	if (tsk == current)
+		max_data->uid = current_uid();
+	else
+		max_data->uid = task_uid(tsk);
+
+	max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
+	max_data->policy = tsk->policy;
+	max_data->rt_priority = tsk->rt_priority;
+
+	/* record this tasks comm */
+	tracing_record_cmdline(tsk);
+	latency_fsnotify(tr);
+}
+
+/**
+ * update_max_tr - snapshot all trace buffers from global_trace to max_tr
+ * @tr: tracer
+ * @tsk: the task with the latency
+ * @cpu: The cpu that initiated the trace.
+ * @cond_data: User data associated with a conditional snapshot
+ *
+ * Flip the buffers between the @tr and the max_tr and record information
+ * about which task was the cause of this latency.
+ */
+void
+update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
+	      void *cond_data)
+{
+	if (tr->stop_count)
+		return;
+
+	WARN_ON_ONCE(!irqs_disabled());
+
+	if (!tr->allocated_snapshot) {
+		/* Only the nop tracer should hit this when disabling */
+		WARN_ON_ONCE(tr->current_trace != &nop_trace);
+		return;
+	}
+
+	arch_spin_lock(&tr->max_lock);
+
+	/* Inherit the recordable setting from array_buffer */
+	if (ring_buffer_record_is_set_on(tr->array_buffer.buffer))
+		ring_buffer_record_on(tr->max_buffer.buffer);
+	else
+		ring_buffer_record_off(tr->max_buffer.buffer);
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+	if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data)) {
+		arch_spin_unlock(&tr->max_lock);
+		return;
+	}
+#endif
+	swap(tr->array_buffer.buffer, tr->max_buffer.buffer);
+
+	__update_max_tr(tr, tsk, cpu);
+
+	arch_spin_unlock(&tr->max_lock);
+
+	/* Any waiters on the old snapshot buffer need to wake up */
+	ring_buffer_wake_waiters(tr->array_buffer.buffer, RING_BUFFER_ALL_CPUS);
+}
+
+/**
+ * update_max_tr_single - only copy one trace over, and reset the rest
+ * @tr: tracer
+ * @tsk: task with the latency
+ * @cpu: the cpu of the buffer to copy.
+ *
+ * Flip the trace of a single CPU buffer between the @tr and the max_tr.
+ */
+void
+update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
+{
+	int ret;
+
+	if (tr->stop_count)
+		return;
+
+	WARN_ON_ONCE(!irqs_disabled());
+	if (!tr->allocated_snapshot) {
+		/* Only the nop tracer should hit this when disabling */
+		WARN_ON_ONCE(tr->current_trace != &nop_trace);
+		return;
+	}
+
+	arch_spin_lock(&tr->max_lock);
+
+	ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->array_buffer.buffer, cpu);
+
+	if (ret == -EBUSY) {
+		/*
+		 * We failed to swap the buffer due to a commit taking
+		 * place on this CPU. We fail to record, but we reset
+		 * the max trace buffer (no one writes directly to it)
+		 * and flag that it failed.
+		 * Another reason is resize is in progress.
+		 */
+		trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
+			"Failed to swap buffers due to commit or resize in progress\n");
+	}
+
+	WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
+
+	__update_max_tr(tr, tsk, cpu);
+	arch_spin_unlock(&tr->max_lock);
+}
+
+#endif /* CONFIG_TRACER_MAX_TRACE */
+
+static int wait_on_pipe(struct trace_iterator *iter, int full)
+{
+	int ret;
+
+	/* Iterators are static, they should be filled or empty */
+	if (trace_buffer_iter(iter, iter->cpu_file))
+		return 0;
+
+	ret = ring_buffer_wait(iter->array_buffer->buffer, iter->cpu_file, full);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	/*
+	 * Make sure this is still the snapshot buffer, as if a snapshot were
+	 * to happen, this would now be the main buffer.
+	 */
+	if (iter->snapshot)
+		iter->array_buffer = &iter->tr->max_buffer;
+#endif
+	return ret;
+}
+
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+static bool selftests_can_run;
+
+struct trace_selftests {
+	struct list_head		list;
+	struct tracer			*type;
+};
+
+static LIST_HEAD(postponed_selftests);
+
+static int save_selftest(struct tracer *type)
+{
+	struct trace_selftests *selftest;
+
+	selftest = kmalloc(sizeof(*selftest), GFP_KERNEL);
+	if (!selftest)
+		return -ENOMEM;
+
+	selftest->type = type;
+	list_add(&selftest->list, &postponed_selftests);
+	return 0;
+}
+
+static int run_tracer_selftest(struct tracer *type)
+{
+	struct trace_array *tr = &global_trace;
+	struct tracer *saved_tracer = tr->current_trace;
+	int ret;
+
+	if (!type->selftest || tracing_selftest_disabled)
+		return 0;
+
+	/*
+	 * If a tracer registers early in boot up (before scheduling is
+	 * initialized and such), then do not run its selftests yet.
+	 * Instead, run it a little later in the boot process.
+	 */
+	if (!selftests_can_run)
+		return save_selftest(type);
+
+	if (!tracing_is_on()) {
+		pr_warn("Selftest for tracer %s skipped due to tracing disabled\n",
+			type->name);
+		return 0;
+	}
+
+	/*
+	 * Run a selftest on this tracer.
+	 * Here we reset the trace buffer, and set the current
+	 * tracer to be this tracer. The tracer can then run some
+	 * internal tracing to verify that everything is in order.
+	 * If we fail, we do not register this tracer.
+	 */
+	tracing_reset_online_cpus(&tr->array_buffer);
+
+	tr->current_trace = type;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (type->use_max_tr) {
+		/* If we expanded the buffers, make sure the max is expanded too */
+		if (ring_buffer_expanded)
+			ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
+					   RING_BUFFER_ALL_CPUS);
+		tr->allocated_snapshot = true;
+	}
+#endif
+
+	/* the test is responsible for initializing and enabling */
+	pr_info("Testing tracer %s: ", type->name);
+	ret = type->selftest(type, tr);
+	/* the test is responsible for resetting too */
+	tr->current_trace = saved_tracer;
+	if (ret) {
+		printk(KERN_CONT "FAILED!\n");
+		/* Add the warning after printing 'FAILED' */
+		WARN_ON(1);
+		return -1;
+	}
+	/* Only reset on passing, to avoid touching corrupted buffers */
+	tracing_reset_online_cpus(&tr->array_buffer);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (type->use_max_tr) {
+		tr->allocated_snapshot = false;
+
+		/* Shrink the max buffer again */
+		if (ring_buffer_expanded)
+			ring_buffer_resize(tr->max_buffer.buffer, 1,
+					   RING_BUFFER_ALL_CPUS);
+	}
+#endif
+
+	printk(KERN_CONT "PASSED\n");
+	return 0;
+}
+
+static __init int init_trace_selftests(void)
+{
+	struct trace_selftests *p, *n;
+	struct tracer *t, **last;
+	int ret;
+
+	selftests_can_run = true;
+
+	mutex_lock(&trace_types_lock);
+
+	if (list_empty(&postponed_selftests))
+		goto out;
+
+	pr_info("Running postponed tracer tests:\n");
+
+	tracing_selftest_running = true;
+	list_for_each_entry_safe(p, n, &postponed_selftests, list) {
+		/* This loop can take minutes when sanitizers are enabled, so
+		 * lets make sure we allow RCU processing.
+		 */
+		cond_resched();
+		ret = run_tracer_selftest(p->type);
+		/* If the test fails, then warn and remove from available_tracers */
+		if (ret < 0) {
+			WARN(1, "tracer: %s failed selftest, disabling\n",
+			     p->type->name);
+			last = &trace_types;
+			for (t = trace_types; t; t = t->next) {
+				if (t == p->type) {
+					*last = t->next;
+					break;
+				}
+				last = &t->next;
+			}
+		}
+		list_del(&p->list);
+		kfree(p);
+	}
+	tracing_selftest_running = false;
+
+ out:
+	mutex_unlock(&trace_types_lock);
+
+	return 0;
+}
+core_initcall(init_trace_selftests);
+#else
+static inline int run_tracer_selftest(struct tracer *type)
+{
+	return 0;
+}
+#endif /* CONFIG_FTRACE_STARTUP_TEST */
+
+static void add_tracer_options(struct trace_array *tr, struct tracer *t);
+
+static void __init apply_trace_boot_options(void);
+
+/**
+ * register_tracer - register a tracer with the ftrace system.
+ * @type: the plugin for the tracer
+ *
+ * Register a new plugin tracer.
+ */
+int __init register_tracer(struct tracer *type)
+{
+	struct tracer *t;
+	int ret = 0;
+
+	if (!type->name) {
+		pr_info("Tracer must have a name\n");
+		return -1;
+	}
+
+	if (strlen(type->name) >= MAX_TRACER_SIZE) {
+		pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
+		return -1;
+	}
+
+	if (security_locked_down(LOCKDOWN_TRACEFS)) {
+		pr_warn("Can not register tracer %s due to lockdown\n",
+			   type->name);
+		return -EPERM;
+	}
+
+	mutex_lock(&trace_types_lock);
+
+	tracing_selftest_running = true;
+
+	for (t = trace_types; t; t = t->next) {
+		if (strcmp(type->name, t->name) == 0) {
+			/* already found */
+			pr_info("Tracer %s already registered\n",
+				type->name);
+			ret = -1;
+			goto out;
+		}
+	}
+
+	if (!type->set_flag)
+		type->set_flag = &dummy_set_flag;
+	if (!type->flags) {
+		/*allocate a dummy tracer_flags*/
+		type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
+		if (!type->flags) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		type->flags->val = 0;
+		type->flags->opts = dummy_tracer_opt;
+	} else
+		if (!type->flags->opts)
+			type->flags->opts = dummy_tracer_opt;
+
+	/* store the tracer for __set_tracer_option */
+	type->flags->trace = type;
+
+	ret = run_tracer_selftest(type);
+	if (ret < 0)
+		goto out;
+
+	type->next = trace_types;
+	trace_types = type;
+	add_tracer_options(&global_trace, type);
+
+ out:
+	tracing_selftest_running = false;
+	mutex_unlock(&trace_types_lock);
+
+	if (ret || !default_bootup_tracer)
+		goto out_unlock;
+
+	if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
+		goto out_unlock;
+
+	printk(KERN_INFO "Starting tracer '%s'\n", type->name);
+	/* Do we want this tracer to start on bootup? */
+	tracing_set_tracer(&global_trace, type->name);
+	default_bootup_tracer = NULL;
+
+	apply_trace_boot_options();
+
+	/* disable other selftests, since this will break it. */
+	disable_tracing_selftest("running a tracer");
+
+ out_unlock:
+	return ret;
+}
+
+static void tracing_reset_cpu(struct array_buffer *buf, int cpu)
+{
+	struct trace_buffer *buffer = buf->buffer;
+
+	if (!buffer)
+		return;
+
+	ring_buffer_record_disable(buffer);
+
+	/* Make sure all commits have finished */
+	synchronize_rcu();
+	ring_buffer_reset_cpu(buffer, cpu);
+
+	ring_buffer_record_enable(buffer);
+}
+
+void tracing_reset_online_cpus(struct array_buffer *buf)
+{
+	struct trace_buffer *buffer = buf->buffer;
+
+	if (!buffer)
+		return;
+
+	ring_buffer_record_disable(buffer);
+
+	/* Make sure all commits have finished */
+	synchronize_rcu();
+
+	buf->time_start = buffer_ftrace_now(buf, buf->cpu);
+
+	ring_buffer_reset_online_cpus(buffer);
+
+	ring_buffer_record_enable(buffer);
+}
+
+/* Must have trace_types_lock held */
+void tracing_reset_all_online_cpus_unlocked(void)
+{
+	struct trace_array *tr;
+
+	lockdep_assert_held(&trace_types_lock);
+
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (!tr->clear_trace)
+			continue;
+		tr->clear_trace = false;
+		tracing_reset_online_cpus(&tr->array_buffer);
+#ifdef CONFIG_TRACER_MAX_TRACE
+		tracing_reset_online_cpus(&tr->max_buffer);
+#endif
+	}
+}
+
+void tracing_reset_all_online_cpus(void)
+{
+	mutex_lock(&trace_types_lock);
+	tracing_reset_all_online_cpus_unlocked();
+	mutex_unlock(&trace_types_lock);
+}
+
+/*
+ * The tgid_map array maps from pid to tgid; i.e. the value stored at index i
+ * is the tgid last observed corresponding to pid=i.
+ */
+static int *tgid_map;
+
+/* The maximum valid index into tgid_map. */
+static size_t tgid_map_max;
+
+#define SAVED_CMDLINES_DEFAULT 128
+#define NO_CMDLINE_MAP UINT_MAX
+/*
+ * Preemption must be disabled before acquiring trace_cmdline_lock.
+ * The various trace_arrays' max_lock must be acquired in a context
+ * where interrupt is disabled.
+ */
+static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
+struct saved_cmdlines_buffer {
+	unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
+	unsigned *map_cmdline_to_pid;
+	unsigned cmdline_num;
+	int cmdline_idx;
+	char *saved_cmdlines;
+};
+static struct saved_cmdlines_buffer *savedcmd;
+
+static inline char *get_saved_cmdlines(int idx)
+{
+	return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
+}
+
+static inline void set_cmdline(int idx, const char *cmdline)
+{
+	strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
+}
+
+static int allocate_cmdlines_buffer(unsigned int val,
+				    struct saved_cmdlines_buffer *s)
+{
+	s->map_cmdline_to_pid = kmalloc_array(val,
+					      sizeof(*s->map_cmdline_to_pid),
+					      GFP_KERNEL);
+	if (!s->map_cmdline_to_pid)
+		return -ENOMEM;
+
+	s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL);
+	if (!s->saved_cmdlines) {
+		kfree(s->map_cmdline_to_pid);
+		return -ENOMEM;
+	}
+
+	s->cmdline_idx = 0;
+	s->cmdline_num = val;
+	memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
+	       sizeof(s->map_pid_to_cmdline));
+	memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
+	       val * sizeof(*s->map_cmdline_to_pid));
+
+	return 0;
+}
+
+static int trace_create_savedcmd(void)
+{
+	int ret;
+
+	savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
+	if (!savedcmd)
+		return -ENOMEM;
+
+	ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
+	if (ret < 0) {
+		kfree(savedcmd);
+		savedcmd = NULL;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+int is_tracing_stopped(void)
+{
+	return global_trace.stop_count;
+}
+
+static void tracing_start_tr(struct trace_array *tr)
+{
+	struct trace_buffer *buffer;
+	unsigned long flags;
+
+	if (tracing_disabled)
+		return;
+
+	raw_spin_lock_irqsave(&tr->start_lock, flags);
+	if (--tr->stop_count) {
+		if (WARN_ON_ONCE(tr->stop_count < 0)) {
+			/* Someone screwed up their debugging */
+			tr->stop_count = 0;
+		}
+		goto out;
+	}
+
+	/* Prevent the buffers from switching */
+	arch_spin_lock(&tr->max_lock);
+
+	buffer = tr->array_buffer.buffer;
+	if (buffer)
+		ring_buffer_record_enable(buffer);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	buffer = tr->max_buffer.buffer;
+	if (buffer)
+		ring_buffer_record_enable(buffer);
+#endif
+
+	arch_spin_unlock(&tr->max_lock);
+
+ out:
+	raw_spin_unlock_irqrestore(&tr->start_lock, flags);
+}
+
+/**
+ * tracing_start - quick start of the tracer
+ *
+ * If tracing is enabled but was stopped by tracing_stop,
+ * this will start the tracer back up.
+ */
+void tracing_start(void)
+
+{
+	return tracing_start_tr(&global_trace);
+}
+
+static void tracing_stop_tr(struct trace_array *tr)
+{
+	struct trace_buffer *buffer;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&tr->start_lock, flags);
+	if (tr->stop_count++)
+		goto out;
+
+	/* Prevent the buffers from switching */
+	arch_spin_lock(&tr->max_lock);
+
+	buffer = tr->array_buffer.buffer;
+	if (buffer)
+		ring_buffer_record_disable(buffer);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	buffer = tr->max_buffer.buffer;
+	if (buffer)
+		ring_buffer_record_disable(buffer);
+#endif
+
+	arch_spin_unlock(&tr->max_lock);
+
+ out:
+	raw_spin_unlock_irqrestore(&tr->start_lock, flags);
+}
+
+/**
+ * tracing_stop - quick stop of the tracer
+ *
+ * Light weight way to stop tracing. Use in conjunction with
+ * tracing_start.
+ */
+void tracing_stop(void)
+{
+	return tracing_stop_tr(&global_trace);
+}
+
+static int trace_save_cmdline(struct task_struct *tsk)
+{
+	unsigned tpid, idx;
+
+	/* treat recording of idle task as a success */
+	if (!tsk->pid)
+		return 1;
+
+	tpid = tsk->pid & (PID_MAX_DEFAULT - 1);
+
+	/*
+	 * It's not the end of the world if we don't get
+	 * the lock, but we also don't want to spin
+	 * nor do we want to disable interrupts,
+	 * so if we miss here, then better luck next time.
+	 *
+	 * This is called within the scheduler and wake up, so interrupts
+	 * had better been disabled and run queue lock been held.
+	 */
+	lockdep_assert_preemption_disabled();
+	if (!arch_spin_trylock(&trace_cmdline_lock))
+		return 0;
+
+	idx = savedcmd->map_pid_to_cmdline[tpid];
+	if (idx == NO_CMDLINE_MAP) {
+		idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
+
+		savedcmd->map_pid_to_cmdline[tpid] = idx;
+		savedcmd->cmdline_idx = idx;
+	}
+
+	savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
+	set_cmdline(idx, tsk->comm);
+
+	arch_spin_unlock(&trace_cmdline_lock);
+
+	return 1;
+}
+
+static void __trace_find_cmdline(int pid, char comm[])
+{
+	unsigned map;
+	int tpid;
+
+	if (!pid) {
+		strcpy(comm, "<idle>");
+		return;
+	}
+
+	if (WARN_ON_ONCE(pid < 0)) {
+		strcpy(comm, "<XXX>");
+		return;
+	}
+
+	tpid = pid & (PID_MAX_DEFAULT - 1);
+	map = savedcmd->map_pid_to_cmdline[tpid];
+	if (map != NO_CMDLINE_MAP) {
+		tpid = savedcmd->map_cmdline_to_pid[map];
+		if (tpid == pid) {
+			strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
+			return;
+		}
+	}
+	strcpy(comm, "<...>");
+}
+
+void trace_find_cmdline(int pid, char comm[])
+{
+	preempt_disable();
+	arch_spin_lock(&trace_cmdline_lock);
+
+	__trace_find_cmdline(pid, comm);
+
+	arch_spin_unlock(&trace_cmdline_lock);
+	preempt_enable();
+}
+
+static int *trace_find_tgid_ptr(int pid)
+{
+	/*
+	 * Pairs with the smp_store_release in set_tracer_flag() to ensure that
+	 * if we observe a non-NULL tgid_map then we also observe the correct
+	 * tgid_map_max.
+	 */
+	int *map = smp_load_acquire(&tgid_map);
+
+	if (unlikely(!map || pid > tgid_map_max))
+		return NULL;
+
+	return &map[pid];
+}
+
+int trace_find_tgid(int pid)
+{
+	int *ptr = trace_find_tgid_ptr(pid);
+
+	return ptr ? *ptr : 0;
+}
+
+static int trace_save_tgid(struct task_struct *tsk)
+{
+	int *ptr;
+
+	/* treat recording of idle task as a success */
+	if (!tsk->pid)
+		return 1;
+
+	ptr = trace_find_tgid_ptr(tsk->pid);
+	if (!ptr)
+		return 0;
+
+	*ptr = tsk->tgid;
+	return 1;
+}
+
+static bool tracing_record_taskinfo_skip(int flags)
+{
+	if (unlikely(!(flags & (TRACE_RECORD_CMDLINE | TRACE_RECORD_TGID))))
+		return true;
+	if (!__this_cpu_read(trace_taskinfo_save))
+		return true;
+	return false;
+}
+
+/**
+ * tracing_record_taskinfo - record the task info of a task
+ *
+ * @task:  task to record
+ * @flags: TRACE_RECORD_CMDLINE for recording comm
+ *         TRACE_RECORD_TGID for recording tgid
+ */
+void tracing_record_taskinfo(struct task_struct *task, int flags)
+{
+	bool done;
+
+	if (tracing_record_taskinfo_skip(flags))
+		return;
+
+	/*
+	 * Record as much task information as possible. If some fail, continue
+	 * to try to record the others.
+	 */
+	done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task);
+	done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task);
+
+	/* If recording any information failed, retry again soon. */
+	if (!done)
+		return;
+
+	__this_cpu_write(trace_taskinfo_save, false);
+}
+
+/**
+ * tracing_record_taskinfo_sched_switch - record task info for sched_switch
+ *
+ * @prev: previous task during sched_switch
+ * @next: next task during sched_switch
+ * @flags: TRACE_RECORD_CMDLINE for recording comm
+ *         TRACE_RECORD_TGID for recording tgid
+ */
+void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
+					  struct task_struct *next, int flags)
+{
+	bool done;
+
+	if (tracing_record_taskinfo_skip(flags))
+		return;
+
+	/*
+	 * Record as much task information as possible. If some fail, continue
+	 * to try to record the others.
+	 */
+	done  = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev);
+	done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next);
+	done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev);
+	done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next);
+
+	/* If recording any information failed, retry again soon. */
+	if (!done)
+		return;
+
+	__this_cpu_write(trace_taskinfo_save, false);
+}
+
+/* Helpers to record a specific task information */
+void tracing_record_cmdline(struct task_struct *task)
+{
+	tracing_record_taskinfo(task, TRACE_RECORD_CMDLINE);
+}
+
+void tracing_record_tgid(struct task_struct *task)
+{
+	tracing_record_taskinfo(task, TRACE_RECORD_TGID);
+}
+
+/*
+ * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
+ * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
+ * simplifies those functions and keeps them in sync.
+ */
+enum print_line_t trace_handle_return(struct trace_seq *s)
+{
+	return trace_seq_has_overflowed(s) ?
+		TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
+}
+EXPORT_SYMBOL_GPL(trace_handle_return);
+
+static unsigned short migration_disable_value(void)
+{
+#if defined(CONFIG_SMP)
+	return current->migration_disabled;
+#else
+	return 0;
+#endif
+}
+
+unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
+{
+	unsigned int trace_flags = irqs_status;
+	unsigned int pc;
+
+	pc = preempt_count();
+
+	if (pc & NMI_MASK)
+		trace_flags |= TRACE_FLAG_NMI;
+	if (pc & HARDIRQ_MASK)
+		trace_flags |= TRACE_FLAG_HARDIRQ;
+	if (in_serving_softirq())
+		trace_flags |= TRACE_FLAG_SOFTIRQ;
+	if (softirq_count() >> (SOFTIRQ_SHIFT + 1))
+		trace_flags |= TRACE_FLAG_BH_OFF;
+
+	if (tif_need_resched())
+		trace_flags |= TRACE_FLAG_NEED_RESCHED;
+	if (test_preempt_need_resched())
+		trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
+	return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) |
+		(min_t(unsigned int, migration_disable_value(), 0xf)) << 4;
+}
+
+struct ring_buffer_event *
+trace_buffer_lock_reserve(struct trace_buffer *buffer,
+			  int type,
+			  unsigned long len,
+			  unsigned int trace_ctx)
+{
+	return __trace_buffer_lock_reserve(buffer, type, len, trace_ctx);
+}
+
+DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
+DEFINE_PER_CPU(int, trace_buffered_event_cnt);
+static int trace_buffered_event_ref;
+
+/**
+ * trace_buffered_event_enable - enable buffering events
+ *
+ * When events are being filtered, it is quicker to use a temporary
+ * buffer to write the event data into if there's a likely chance
+ * that it will not be committed. The discard of the ring buffer
+ * is not as fast as committing, and is much slower than copying
+ * a commit.
+ *
+ * When an event is to be filtered, allocate per cpu buffers to
+ * write the event data into, and if the event is filtered and discarded
+ * it is simply dropped, otherwise, the entire data is to be committed
+ * in one shot.
+ */
+void trace_buffered_event_enable(void)
+{
+	struct ring_buffer_event *event;
+	struct page *page;
+	int cpu;
+
+	WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
+
+	if (trace_buffered_event_ref++)
+		return;
+
+	for_each_tracing_cpu(cpu) {
+		page = alloc_pages_node(cpu_to_node(cpu),
+					GFP_KERNEL | __GFP_NORETRY, 0);
+		/* This is just an optimization and can handle failures */
+		if (!page) {
+			pr_err("Failed to allocate event buffer\n");
+			break;
+		}
+
+		event = page_address(page);
+		memset(event, 0, sizeof(*event));
+
+		per_cpu(trace_buffered_event, cpu) = event;
+
+		preempt_disable();
+		if (cpu == smp_processor_id() &&
+		    __this_cpu_read(trace_buffered_event) !=
+		    per_cpu(trace_buffered_event, cpu))
+			WARN_ON_ONCE(1);
+		preempt_enable();
+	}
+}
+
+static void enable_trace_buffered_event(void *data)
+{
+	/* Probably not needed, but do it anyway */
+	smp_rmb();
+	this_cpu_dec(trace_buffered_event_cnt);
+}
+
+static void disable_trace_buffered_event(void *data)
+{
+	this_cpu_inc(trace_buffered_event_cnt);
+}
+
+/**
+ * trace_buffered_event_disable - disable buffering events
+ *
+ * When a filter is removed, it is faster to not use the buffered
+ * events, and to commit directly into the ring buffer. Free up
+ * the temp buffers when there are no more users. This requires
+ * special synchronization with current events.
+ */
+void trace_buffered_event_disable(void)
+{
+	int cpu;
+
+	WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
+
+	if (WARN_ON_ONCE(!trace_buffered_event_ref))
+		return;
+
+	if (--trace_buffered_event_ref)
+		return;
+
+	/* For each CPU, set the buffer as used. */
+	on_each_cpu_mask(tracing_buffer_mask, disable_trace_buffered_event,
+			 NULL, true);
+
+	/* Wait for all current users to finish */
+	synchronize_rcu();
+
+	for_each_tracing_cpu(cpu) {
+		free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
+		per_cpu(trace_buffered_event, cpu) = NULL;
+	}
+
+	/*
+	 * Wait for all CPUs that potentially started checking if they can use
+	 * their event buffer only after the previous synchronize_rcu() call and
+	 * they still read a valid pointer from trace_buffered_event. It must be
+	 * ensured they don't see cleared trace_buffered_event_cnt else they
+	 * could wrongly decide to use the pointed-to buffer which is now freed.
+	 */
+	synchronize_rcu();
+
+	/* For each CPU, relinquish the buffer */
+	on_each_cpu_mask(tracing_buffer_mask, enable_trace_buffered_event, NULL,
+			 true);
+}
+
+static struct trace_buffer *temp_buffer;
+
+struct ring_buffer_event *
+trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
+			  struct trace_event_file *trace_file,
+			  int type, unsigned long len,
+			  unsigned int trace_ctx)
+{
+	struct ring_buffer_event *entry;
+	struct trace_array *tr = trace_file->tr;
+	int val;
+
+	*current_rb = tr->array_buffer.buffer;
+
+	if (!tr->no_filter_buffering_ref &&
+	    (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED))) {
+		preempt_disable_notrace();
+		/*
+		 * Filtering is on, so try to use the per cpu buffer first.
+		 * This buffer will simulate a ring_buffer_event,
+		 * where the type_len is zero and the array[0] will
+		 * hold the full length.
+		 * (see include/linux/ring-buffer.h for details on
+		 *  how the ring_buffer_event is structured).
+		 *
+		 * Using a temp buffer during filtering and copying it
+		 * on a matched filter is quicker than writing directly
+		 * into the ring buffer and then discarding it when
+		 * it doesn't match. That is because the discard
+		 * requires several atomic operations to get right.
+		 * Copying on match and doing nothing on a failed match
+		 * is still quicker than no copy on match, but having
+		 * to discard out of the ring buffer on a failed match.
+		 */
+		if ((entry = __this_cpu_read(trace_buffered_event))) {
+			int max_len = PAGE_SIZE - struct_size(entry, array, 1);
+
+			val = this_cpu_inc_return(trace_buffered_event_cnt);
+
+			/*
+			 * Preemption is disabled, but interrupts and NMIs
+			 * can still come in now. If that happens after
+			 * the above increment, then it will have to go
+			 * back to the old method of allocating the event
+			 * on the ring buffer, and if the filter fails, it
+			 * will have to call ring_buffer_discard_commit()
+			 * to remove it.
+			 *
+			 * Need to also check the unlikely case that the
+			 * length is bigger than the temp buffer size.
+			 * If that happens, then the reserve is pretty much
+			 * guaranteed to fail, as the ring buffer currently
+			 * only allows events less than a page. But that may
+			 * change in the future, so let the ring buffer reserve
+			 * handle the failure in that case.
+			 */
+			if (val == 1 && likely(len <= max_len)) {
+				trace_event_setup(entry, type, trace_ctx);
+				entry->array[0] = len;
+				/* Return with preemption disabled */
+				return entry;
+			}
+			this_cpu_dec(trace_buffered_event_cnt);
+		}
+		/* __trace_buffer_lock_reserve() disables preemption */
+		preempt_enable_notrace();
+	}
+
+	entry = __trace_buffer_lock_reserve(*current_rb, type, len,
+					    trace_ctx);
+	/*
+	 * If tracing is off, but we have triggers enabled
+	 * we still need to look at the event data. Use the temp_buffer
+	 * to store the trace event for the trigger to use. It's recursive
+	 * safe and will not be recorded anywhere.
+	 */
+	if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
+		*current_rb = temp_buffer;
+		entry = __trace_buffer_lock_reserve(*current_rb, type, len,
+						    trace_ctx);
+	}
+	return entry;
+}
+EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
+
+static DEFINE_RAW_SPINLOCK(tracepoint_iter_lock);
+static DEFINE_MUTEX(tracepoint_printk_mutex);
+
+static void output_printk(struct trace_event_buffer *fbuffer)
+{
+	struct trace_event_call *event_call;
+	struct trace_event_file *file;
+	struct trace_event *event;
+	unsigned long flags;
+	struct trace_iterator *iter = tracepoint_print_iter;
+
+	/* We should never get here if iter is NULL */
+	if (WARN_ON_ONCE(!iter))
+		return;
+
+	event_call = fbuffer->trace_file->event_call;
+	if (!event_call || !event_call->event.funcs ||
+	    !event_call->event.funcs->trace)
+		return;
+
+	file = fbuffer->trace_file;
+	if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) ||
+	    (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
+	     !filter_match_preds(file->filter, fbuffer->entry)))
+		return;
+
+	event = &fbuffer->trace_file->event_call->event;
+
+	raw_spin_lock_irqsave(&tracepoint_iter_lock, flags);
+	trace_seq_init(&iter->seq);
+	iter->ent = fbuffer->entry;
+	event_call->event.funcs->trace(iter, 0, event);
+	trace_seq_putc(&iter->seq, 0);
+	printk("%s", iter->seq.buffer);
+
+	raw_spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
+}
+
+int tracepoint_printk_sysctl(struct ctl_table *table, int write,
+			     void *buffer, size_t *lenp,
+			     loff_t *ppos)
+{
+	int save_tracepoint_printk;
+	int ret;
+
+	mutex_lock(&tracepoint_printk_mutex);
+	save_tracepoint_printk = tracepoint_printk;
+
+	ret = proc_dointvec(table, write, buffer, lenp, ppos);
+
+	/*
+	 * This will force exiting early, as tracepoint_printk
+	 * is always zero when tracepoint_printk_iter is not allocated
+	 */
+	if (!tracepoint_print_iter)
+		tracepoint_printk = 0;
+
+	if (save_tracepoint_printk == tracepoint_printk)
+		goto out;
+
+	if (tracepoint_printk)
+		static_key_enable(&tracepoint_printk_key.key);
+	else
+		static_key_disable(&tracepoint_printk_key.key);
+
+ out:
+	mutex_unlock(&tracepoint_printk_mutex);
+
+	return ret;
+}
+
+void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
+{
+	enum event_trigger_type tt = ETT_NONE;
+	struct trace_event_file *file = fbuffer->trace_file;
+
+	if (__event_trigger_test_discard(file, fbuffer->buffer, fbuffer->event,
+			fbuffer->entry, &tt))
+		goto discard;
+
+	if (static_key_false(&tracepoint_printk_key.key))
+		output_printk(fbuffer);
+
+	if (static_branch_unlikely(&trace_event_exports_enabled))
+		ftrace_exports(fbuffer->event, TRACE_EXPORT_EVENT);
+
+	trace_buffer_unlock_commit_regs(file->tr, fbuffer->buffer,
+			fbuffer->event, fbuffer->trace_ctx, fbuffer->regs);
+
+discard:
+	if (tt)
+		event_triggers_post_call(file, tt);
+
+}
+EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
+
+/*
+ * Skip 3:
+ *
+ *   trace_buffer_unlock_commit_regs()
+ *   trace_event_buffer_commit()
+ *   trace_event_raw_event_xxx()
+ */
+# define STACK_SKIP 3
+
+void trace_buffer_unlock_commit_regs(struct trace_array *tr,
+				     struct trace_buffer *buffer,
+				     struct ring_buffer_event *event,
+				     unsigned int trace_ctx,
+				     struct pt_regs *regs)
+{
+	__buffer_unlock_commit(buffer, event);
+
+	/*
+	 * If regs is not set, then skip the necessary functions.
+	 * Note, we can still get here via blktrace, wakeup tracer
+	 * and mmiotrace, but that's ok if they lose a function or
+	 * two. They are not that meaningful.
+	 */
+	ftrace_trace_stack(tr, buffer, trace_ctx, regs ? 0 : STACK_SKIP, regs);
+	ftrace_trace_userstack(tr, buffer, trace_ctx);
+}
+
+/*
+ * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
+ */
+void
+trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
+				   struct ring_buffer_event *event)
+{
+	__buffer_unlock_commit(buffer, event);
+}
+
+void
+trace_function(struct trace_array *tr, unsigned long ip, unsigned long
+	       parent_ip, unsigned int trace_ctx)
+{
+	struct trace_event_call *call = &event_function;
+	struct trace_buffer *buffer = tr->array_buffer.buffer;
+	struct ring_buffer_event *event;
+	struct ftrace_entry *entry;
+
+	event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
+					    trace_ctx);
+	if (!event)
+		return;
+	entry	= ring_buffer_event_data(event);
+	entry->ip			= ip;
+	entry->parent_ip		= parent_ip;
+
+	if (!call_filter_check_discard(call, entry, buffer, event)) {
+		if (static_branch_unlikely(&trace_function_exports_enabled))
+			ftrace_exports(event, TRACE_EXPORT_FUNCTION);
+		__buffer_unlock_commit(buffer, event);
+	}
+}
+
+#ifdef CONFIG_STACKTRACE
+
+/* Allow 4 levels of nesting: normal, softirq, irq, NMI */
+#define FTRACE_KSTACK_NESTING	4
+
+#define FTRACE_KSTACK_ENTRIES	(PAGE_SIZE / FTRACE_KSTACK_NESTING)
+
+struct ftrace_stack {
+	unsigned long		calls[FTRACE_KSTACK_ENTRIES];
+};
+
+
+struct ftrace_stacks {
+	struct ftrace_stack	stacks[FTRACE_KSTACK_NESTING];
+};
+
+static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks);
+static DEFINE_PER_CPU(int, ftrace_stack_reserve);
+
+static void __ftrace_trace_stack(struct trace_buffer *buffer,
+				 unsigned int trace_ctx,
+				 int skip, struct pt_regs *regs)
+{
+	struct trace_event_call *call = &event_kernel_stack;
+	struct ring_buffer_event *event;
+	unsigned int size, nr_entries;
+	struct ftrace_stack *fstack;
+	struct stack_entry *entry;
+	int stackidx;
+
+	/*
+	 * Add one, for this function and the call to save_stack_trace()
+	 * If regs is set, then these functions will not be in the way.
+	 */
+#ifndef CONFIG_UNWINDER_ORC
+	if (!regs)
+		skip++;
+#endif
+
+	preempt_disable_notrace();
+
+	stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
+
+	/* This should never happen. If it does, yell once and skip */
+	if (WARN_ON_ONCE(stackidx >= FTRACE_KSTACK_NESTING))
+		goto out;
+
+	/*
+	 * The above __this_cpu_inc_return() is 'atomic' cpu local. An
+	 * interrupt will either see the value pre increment or post
+	 * increment. If the interrupt happens pre increment it will have
+	 * restored the counter when it returns.  We just need a barrier to
+	 * keep gcc from moving things around.
+	 */
+	barrier();
+
+	fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx;
+	size = ARRAY_SIZE(fstack->calls);
+
+	if (regs) {
+		nr_entries = stack_trace_save_regs(regs, fstack->calls,
+						   size, skip);
+	} else {
+		nr_entries = stack_trace_save(fstack->calls, size, skip);
+	}
+
+	size = nr_entries * sizeof(unsigned long);
+	event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
+				    (sizeof(*entry) - sizeof(entry->caller)) + size,
+				    trace_ctx);
+	if (!event)
+		goto out;
+	entry = ring_buffer_event_data(event);
+
+	memcpy(&entry->caller, fstack->calls, size);
+	entry->size = nr_entries;
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		__buffer_unlock_commit(buffer, event);
+
+ out:
+	/* Again, don't let gcc optimize things here */
+	barrier();
+	__this_cpu_dec(ftrace_stack_reserve);
+	preempt_enable_notrace();
+
+}
+
+static inline void ftrace_trace_stack(struct trace_array *tr,
+				      struct trace_buffer *buffer,
+				      unsigned int trace_ctx,
+				      int skip, struct pt_regs *regs)
+{
+	if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
+		return;
+
+	__ftrace_trace_stack(buffer, trace_ctx, skip, regs);
+}
+
+void __trace_stack(struct trace_array *tr, unsigned int trace_ctx,
+		   int skip)
+{
+	struct trace_buffer *buffer = tr->array_buffer.buffer;
+
+	if (rcu_is_watching()) {
+		__ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
+		return;
+	}
+
+	/*
+	 * When an NMI triggers, RCU is enabled via ct_nmi_enter(),
+	 * but if the above rcu_is_watching() failed, then the NMI
+	 * triggered someplace critical, and ct_irq_enter() should
+	 * not be called from NMI.
+	 */
+	if (unlikely(in_nmi()))
+		return;
+
+	ct_irq_enter_irqson();
+	__ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
+	ct_irq_exit_irqson();
+}
+
+/**
+ * trace_dump_stack - record a stack back trace in the trace buffer
+ * @skip: Number of functions to skip (helper handlers)
+ */
+void trace_dump_stack(int skip)
+{
+	if (tracing_disabled || tracing_selftest_running)
+		return;
+
+#ifndef CONFIG_UNWINDER_ORC
+	/* Skip 1 to skip this function. */
+	skip++;
+#endif
+	__ftrace_trace_stack(global_trace.array_buffer.buffer,
+			     tracing_gen_ctx(), skip, NULL);
+}
+EXPORT_SYMBOL_GPL(trace_dump_stack);
+
+#ifdef CONFIG_USER_STACKTRACE_SUPPORT
+static DEFINE_PER_CPU(int, user_stack_count);
+
+static void
+ftrace_trace_userstack(struct trace_array *tr,
+		       struct trace_buffer *buffer, unsigned int trace_ctx)
+{
+	struct trace_event_call *call = &event_user_stack;
+	struct ring_buffer_event *event;
+	struct userstack_entry *entry;
+
+	if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE))
+		return;
+
+	/*
+	 * NMIs can not handle page faults, even with fix ups.
+	 * The save user stack can (and often does) fault.
+	 */
+	if (unlikely(in_nmi()))
+		return;
+
+	/*
+	 * prevent recursion, since the user stack tracing may
+	 * trigger other kernel events.
+	 */
+	preempt_disable();
+	if (__this_cpu_read(user_stack_count))
+		goto out;
+
+	__this_cpu_inc(user_stack_count);
+
+	event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
+					    sizeof(*entry), trace_ctx);
+	if (!event)
+		goto out_drop_count;
+	entry	= ring_buffer_event_data(event);
+
+	entry->tgid		= current->tgid;
+	memset(&entry->caller, 0, sizeof(entry->caller));
+
+	stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES);
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		__buffer_unlock_commit(buffer, event);
+
+ out_drop_count:
+	__this_cpu_dec(user_stack_count);
+ out:
+	preempt_enable();
+}
+#else /* CONFIG_USER_STACKTRACE_SUPPORT */
+static void ftrace_trace_userstack(struct trace_array *tr,
+				   struct trace_buffer *buffer,
+				   unsigned int trace_ctx)
+{
+}
+#endif /* !CONFIG_USER_STACKTRACE_SUPPORT */
+
+#endif /* CONFIG_STACKTRACE */
+
+static inline void
+func_repeats_set_delta_ts(struct func_repeats_entry *entry,
+			  unsigned long long delta)
+{
+	entry->bottom_delta_ts = delta & U32_MAX;
+	entry->top_delta_ts = (delta >> 32);
+}
+
+void trace_last_func_repeats(struct trace_array *tr,
+			     struct trace_func_repeats *last_info,
+			     unsigned int trace_ctx)
+{
+	struct trace_buffer *buffer = tr->array_buffer.buffer;
+	struct func_repeats_entry *entry;
+	struct ring_buffer_event *event;
+	u64 delta;
+
+	event = __trace_buffer_lock_reserve(buffer, TRACE_FUNC_REPEATS,
+					    sizeof(*entry), trace_ctx);
+	if (!event)
+		return;
+
+	delta = ring_buffer_event_time_stamp(buffer, event) -
+		last_info->ts_last_call;
+
+	entry = ring_buffer_event_data(event);
+	entry->ip = last_info->ip;
+	entry->parent_ip = last_info->parent_ip;
+	entry->count = last_info->count;
+	func_repeats_set_delta_ts(entry, delta);
+
+	__buffer_unlock_commit(buffer, event);
+}
+
+/* created for use with alloc_percpu */
+struct trace_buffer_struct {
+	int nesting;
+	char buffer[4][TRACE_BUF_SIZE];
+};
+
+static struct trace_buffer_struct __percpu *trace_percpu_buffer;
+
+/*
+ * This allows for lockless recording.  If we're nested too deeply, then
+ * this returns NULL.
+ */
+static char *get_trace_buf(void)
+{
+	struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
+
+	if (!trace_percpu_buffer || buffer->nesting >= 4)
+		return NULL;
+
+	buffer->nesting++;
+
+	/* Interrupts must see nesting incremented before we use the buffer */
+	barrier();
+	return &buffer->buffer[buffer->nesting - 1][0];
+}
+
+static void put_trace_buf(void)
+{
+	/* Don't let the decrement of nesting leak before this */
+	barrier();
+	this_cpu_dec(trace_percpu_buffer->nesting);
+}
+
+static int alloc_percpu_trace_buffer(void)
+{
+	struct trace_buffer_struct __percpu *buffers;
+
+	if (trace_percpu_buffer)
+		return 0;
+
+	buffers = alloc_percpu(struct trace_buffer_struct);
+	if (MEM_FAIL(!buffers, "Could not allocate percpu trace_printk buffer"))
+		return -ENOMEM;
+
+	trace_percpu_buffer = buffers;
+	return 0;
+}
+
+static int buffers_allocated;
+
+void trace_printk_init_buffers(void)
+{
+	if (buffers_allocated)
+		return;
+
+	if (alloc_percpu_trace_buffer())
+		return;
+
+	/* trace_printk() is for debug use only. Don't use it in production. */
+
+	pr_warn("\n");
+	pr_warn("**********************************************************\n");
+	pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
+	pr_warn("**                                                      **\n");
+	pr_warn("** trace_printk() being used. Allocating extra memory.  **\n");
+	pr_warn("**                                                      **\n");
+	pr_warn("** This means that this is a DEBUG kernel and it is     **\n");
+	pr_warn("** unsafe for production use.                           **\n");
+	pr_warn("**                                                      **\n");
+	pr_warn("** If you see this message and you are not debugging    **\n");
+	pr_warn("** the kernel, report this immediately to your vendor!  **\n");
+	pr_warn("**                                                      **\n");
+	pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
+	pr_warn("**********************************************************\n");
+
+	/* Expand the buffers to set size */
+	tracing_update_buffers();
+
+	buffers_allocated = 1;
+
+	/*
+	 * trace_printk_init_buffers() can be called by modules.
+	 * If that happens, then we need to start cmdline recording
+	 * directly here. If the global_trace.buffer is already
+	 * allocated here, then this was called by module code.
+	 */
+	if (global_trace.array_buffer.buffer)
+		tracing_start_cmdline_record();
+}
+EXPORT_SYMBOL_GPL(trace_printk_init_buffers);
+
+void trace_printk_start_comm(void)
+{
+	/* Start tracing comms if trace printk is set */
+	if (!buffers_allocated)
+		return;
+	tracing_start_cmdline_record();
+}
+
+static void trace_printk_start_stop_comm(int enabled)
+{
+	if (!buffers_allocated)
+		return;
+
+	if (enabled)
+		tracing_start_cmdline_record();
+	else
+		tracing_stop_cmdline_record();
+}
+
+/**
+ * trace_vbprintk - write binary msg to tracing buffer
+ * @ip:    The address of the caller
+ * @fmt:   The string format to write to the buffer
+ * @args:  Arguments for @fmt
+ */
+int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
+{
+	struct trace_event_call *call = &event_bprint;
+	struct ring_buffer_event *event;
+	struct trace_buffer *buffer;
+	struct trace_array *tr = &global_trace;
+	struct bprint_entry *entry;
+	unsigned int trace_ctx;
+	char *tbuffer;
+	int len = 0, size;
+
+	if (unlikely(tracing_selftest_running || tracing_disabled))
+		return 0;
+
+	/* Don't pollute graph traces with trace_vprintk internals */
+	pause_graph_tracing();
+
+	trace_ctx = tracing_gen_ctx();
+	preempt_disable_notrace();
+
+	tbuffer = get_trace_buf();
+	if (!tbuffer) {
+		len = 0;
+		goto out_nobuffer;
+	}
+
+	len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
+
+	if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
+		goto out_put;
+
+	size = sizeof(*entry) + sizeof(u32) * len;
+	buffer = tr->array_buffer.buffer;
+	ring_buffer_nest_start(buffer);
+	event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
+					    trace_ctx);
+	if (!event)
+		goto out;
+	entry = ring_buffer_event_data(event);
+	entry->ip			= ip;
+	entry->fmt			= fmt;
+
+	memcpy(entry->buf, tbuffer, sizeof(u32) * len);
+	if (!call_filter_check_discard(call, entry, buffer, event)) {
+		__buffer_unlock_commit(buffer, event);
+		ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL);
+	}
+
+out:
+	ring_buffer_nest_end(buffer);
+out_put:
+	put_trace_buf();
+
+out_nobuffer:
+	preempt_enable_notrace();
+	unpause_graph_tracing();
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(trace_vbprintk);
+
+__printf(3, 0)
+static int
+__trace_array_vprintk(struct trace_buffer *buffer,
+		      unsigned long ip, const char *fmt, va_list args)
+{
+	struct trace_event_call *call = &event_print;
+	struct ring_buffer_event *event;
+	int len = 0, size;
+	struct print_entry *entry;
+	unsigned int trace_ctx;
+	char *tbuffer;
+
+	if (tracing_disabled || tracing_selftest_running)
+		return 0;
+
+	/* Don't pollute graph traces with trace_vprintk internals */
+	pause_graph_tracing();
+
+	trace_ctx = tracing_gen_ctx();
+	preempt_disable_notrace();
+
+
+	tbuffer = get_trace_buf();
+	if (!tbuffer) {
+		len = 0;
+		goto out_nobuffer;
+	}
+
+	len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
+
+	size = sizeof(*entry) + len + 1;
+	ring_buffer_nest_start(buffer);
+	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
+					    trace_ctx);
+	if (!event)
+		goto out;
+	entry = ring_buffer_event_data(event);
+	entry->ip = ip;
+
+	memcpy(&entry->buf, tbuffer, len + 1);
+	if (!call_filter_check_discard(call, entry, buffer, event)) {
+		__buffer_unlock_commit(buffer, event);
+		ftrace_trace_stack(&global_trace, buffer, trace_ctx, 6, NULL);
+	}
+
+out:
+	ring_buffer_nest_end(buffer);
+	put_trace_buf();
+
+out_nobuffer:
+	preempt_enable_notrace();
+	unpause_graph_tracing();
+
+	return len;
+}
+
+__printf(3, 0)
+int trace_array_vprintk(struct trace_array *tr,
+			unsigned long ip, const char *fmt, va_list args)
+{
+	return __trace_array_vprintk(tr->array_buffer.buffer, ip, fmt, args);
+}
+
+/**
+ * trace_array_printk - Print a message to a specific instance
+ * @tr: The instance trace_array descriptor
+ * @ip: The instruction pointer that this is called from.
+ * @fmt: The format to print (printf format)
+ *
+ * If a subsystem sets up its own instance, they have the right to
+ * printk strings into their tracing instance buffer using this
+ * function. Note, this function will not write into the top level
+ * buffer (use trace_printk() for that), as writing into the top level
+ * buffer should only have events that can be individually disabled.
+ * trace_printk() is only used for debugging a kernel, and should not
+ * be ever incorporated in normal use.
+ *
+ * trace_array_printk() can be used, as it will not add noise to the
+ * top level tracing buffer.
+ *
+ * Note, trace_array_init_printk() must be called on @tr before this
+ * can be used.
+ */
+__printf(3, 0)
+int trace_array_printk(struct trace_array *tr,
+		       unsigned long ip, const char *fmt, ...)
+{
+	int ret;
+	va_list ap;
+
+	if (!tr)
+		return -ENOENT;
+
+	/* This is only allowed for created instances */
+	if (tr == &global_trace)
+		return 0;
+
+	if (!(tr->trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	va_start(ap, fmt);
+	ret = trace_array_vprintk(tr, ip, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(trace_array_printk);
+
+/**
+ * trace_array_init_printk - Initialize buffers for trace_array_printk()
+ * @tr: The trace array to initialize the buffers for
+ *
+ * As trace_array_printk() only writes into instances, they are OK to
+ * have in the kernel (unlike trace_printk()). This needs to be called
+ * before trace_array_printk() can be used on a trace_array.
+ */
+int trace_array_init_printk(struct trace_array *tr)
+{
+	if (!tr)
+		return -ENOENT;
+
+	/* This is only allowed for created instances */
+	if (tr == &global_trace)
+		return -EINVAL;
+
+	return alloc_percpu_trace_buffer();
+}
+EXPORT_SYMBOL_GPL(trace_array_init_printk);
+
+__printf(3, 4)
+int trace_array_printk_buf(struct trace_buffer *buffer,
+			   unsigned long ip, const char *fmt, ...)
+{
+	int ret;
+	va_list ap;
+
+	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	va_start(ap, fmt);
+	ret = __trace_array_vprintk(buffer, ip, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
+__printf(2, 0)
+int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
+{
+	return trace_array_vprintk(&global_trace, ip, fmt, args);
+}
+EXPORT_SYMBOL_GPL(trace_vprintk);
+
+static void trace_iterator_increment(struct trace_iterator *iter)
+{
+	struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
+
+	iter->idx++;
+	if (buf_iter)
+		ring_buffer_iter_advance(buf_iter);
+}
+
+static struct trace_entry *
+peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
+		unsigned long *lost_events)
+{
+	struct ring_buffer_event *event;
+	struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
+
+	if (buf_iter) {
+		event = ring_buffer_iter_peek(buf_iter, ts);
+		if (lost_events)
+			*lost_events = ring_buffer_iter_dropped(buf_iter) ?
+				(unsigned long)-1 : 0;
+	} else {
+		event = ring_buffer_peek(iter->array_buffer->buffer, cpu, ts,
+					 lost_events);
+	}
+
+	if (event) {
+		iter->ent_size = ring_buffer_event_length(event);
+		return ring_buffer_event_data(event);
+	}
+	iter->ent_size = 0;
+	return NULL;
+}
+
+static struct trace_entry *
+__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
+		  unsigned long *missing_events, u64 *ent_ts)
+{
+	struct trace_buffer *buffer = iter->array_buffer->buffer;
+	struct trace_entry *ent, *next = NULL;
+	unsigned long lost_events = 0, next_lost = 0;
+	int cpu_file = iter->cpu_file;
+	u64 next_ts = 0, ts;
+	int next_cpu = -1;
+	int next_size = 0;
+	int cpu;
+
+	/*
+	 * If we are in a per_cpu trace file, don't bother by iterating over
+	 * all cpu and peek directly.
+	 */
+	if (cpu_file > RING_BUFFER_ALL_CPUS) {
+		if (ring_buffer_empty_cpu(buffer, cpu_file))
+			return NULL;
+		ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
+		if (ent_cpu)
+			*ent_cpu = cpu_file;
+
+		return ent;
+	}
+
+	for_each_tracing_cpu(cpu) {
+
+		if (ring_buffer_empty_cpu(buffer, cpu))
+			continue;
+
+		ent = peek_next_entry(iter, cpu, &ts, &lost_events);
+
+		/*
+		 * Pick the entry with the smallest timestamp:
+		 */
+		if (ent && (!next || ts < next_ts)) {
+			next = ent;
+			next_cpu = cpu;
+			next_ts = ts;
+			next_lost = lost_events;
+			next_size = iter->ent_size;
+		}
+	}
+
+	iter->ent_size = next_size;
+
+	if (ent_cpu)
+		*ent_cpu = next_cpu;
+
+	if (ent_ts)
+		*ent_ts = next_ts;
+
+	if (missing_events)
+		*missing_events = next_lost;
+
+	return next;
+}
+
+#define STATIC_FMT_BUF_SIZE	128
+static char static_fmt_buf[STATIC_FMT_BUF_SIZE];
+
+static char *trace_iter_expand_format(struct trace_iterator *iter)
+{
+	char *tmp;
+
+	/*
+	 * iter->tr is NULL when used with tp_printk, which makes
+	 * this get called where it is not safe to call krealloc().
+	 */
+	if (!iter->tr || iter->fmt == static_fmt_buf)
+		return NULL;
+
+	tmp = krealloc(iter->fmt, iter->fmt_size + STATIC_FMT_BUF_SIZE,
+		       GFP_KERNEL);
+	if (tmp) {
+		iter->fmt_size += STATIC_FMT_BUF_SIZE;
+		iter->fmt = tmp;
+	}
+
+	return tmp;
+}
+
+/* Returns true if the string is safe to dereference from an event */
+static bool trace_safe_str(struct trace_iterator *iter, const char *str,
+			   bool star, int len)
+{
+	unsigned long addr = (unsigned long)str;
+	struct trace_event *trace_event;
+	struct trace_event_call *event;
+
+	/* Ignore strings with no length */
+	if (star && !len)
+		return true;
+
+	/* OK if part of the event data */
+	if ((addr >= (unsigned long)iter->ent) &&
+	    (addr < (unsigned long)iter->ent + iter->ent_size))
+		return true;
+
+	/* OK if part of the temp seq buffer */
+	if ((addr >= (unsigned long)iter->tmp_seq.buffer) &&
+	    (addr < (unsigned long)iter->tmp_seq.buffer + PAGE_SIZE))
+		return true;
+
+	/* Core rodata can not be freed */
+	if (is_kernel_rodata(addr))
+		return true;
+
+	if (trace_is_tracepoint_string(str))
+		return true;
+
+	/*
+	 * Now this could be a module event, referencing core module
+	 * data, which is OK.
+	 */
+	if (!iter->ent)
+		return false;
+
+	trace_event = ftrace_find_event(iter->ent->type);
+	if (!trace_event)
+		return false;
+
+	event = container_of(trace_event, struct trace_event_call, event);
+	if ((event->flags & TRACE_EVENT_FL_DYNAMIC) || !event->module)
+		return false;
+
+	/* Would rather have rodata, but this will suffice */
+	if (within_module_core(addr, event->module))
+		return true;
+
+	return false;
+}
+
+static const char *show_buffer(struct trace_seq *s)
+{
+	struct seq_buf *seq = &s->seq;
+
+	seq_buf_terminate(seq);
+
+	return seq->buffer;
+}
+
+static DEFINE_STATIC_KEY_FALSE(trace_no_verify);
+
+static int test_can_verify_check(const char *fmt, ...)
+{
+	char buf[16];
+	va_list ap;
+	int ret;
+
+	/*
+	 * The verifier is dependent on vsnprintf() modifies the va_list
+	 * passed to it, where it is sent as a reference. Some architectures
+	 * (like x86_32) passes it by value, which means that vsnprintf()
+	 * does not modify the va_list passed to it, and the verifier
+	 * would then need to be able to understand all the values that
+	 * vsnprintf can use. If it is passed by value, then the verifier
+	 * is disabled.
+	 */
+	va_start(ap, fmt);
+	vsnprintf(buf, 16, "%d", ap);
+	ret = va_arg(ap, int);
+	va_end(ap);
+
+	return ret;
+}
+
+static void test_can_verify(void)
+{
+	if (!test_can_verify_check("%d %d", 0, 1)) {
+		pr_info("trace event string verifier disabled\n");
+		static_branch_inc(&trace_no_verify);
+	}
+}
+
+/**
+ * trace_check_vprintf - Check dereferenced strings while writing to the seq buffer
+ * @iter: The iterator that holds the seq buffer and the event being printed
+ * @fmt: The format used to print the event
+ * @ap: The va_list holding the data to print from @fmt.
+ *
+ * This writes the data into the @iter->seq buffer using the data from
+ * @fmt and @ap. If the format has a %s, then the source of the string
+ * is examined to make sure it is safe to print, otherwise it will
+ * warn and print "[UNSAFE MEMORY]" in place of the dereferenced string
+ * pointer.
+ */
+void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
+			 va_list ap)
+{
+	const char *p = fmt;
+	const char *str;
+	int i, j;
+
+	if (WARN_ON_ONCE(!fmt))
+		return;
+
+	if (static_branch_unlikely(&trace_no_verify))
+		goto print;
+
+	/* Don't bother checking when doing a ftrace_dump() */
+	if (iter->fmt == static_fmt_buf)
+		goto print;
+
+	while (*p) {
+		bool star = false;
+		int len = 0;
+
+		j = 0;
+
+		/* We only care about %s and variants */
+		for (i = 0; p[i]; i++) {
+			if (i + 1 >= iter->fmt_size) {
+				/*
+				 * If we can't expand the copy buffer,
+				 * just print it.
+				 */
+				if (!trace_iter_expand_format(iter))
+					goto print;
+			}
+
+			if (p[i] == '\\' && p[i+1]) {
+				i++;
+				continue;
+			}
+			if (p[i] == '%') {
+				/* Need to test cases like %08.*s */
+				for (j = 1; p[i+j]; j++) {
+					if (isdigit(p[i+j]) ||
+					    p[i+j] == '.')
+						continue;
+					if (p[i+j] == '*') {
+						star = true;
+						continue;
+					}
+					break;
+				}
+				if (p[i+j] == 's')
+					break;
+				star = false;
+			}
+			j = 0;
+		}
+		/* If no %s found then just print normally */
+		if (!p[i])
+			break;
+
+		/* Copy up to the %s, and print that */
+		strncpy(iter->fmt, p, i);
+		iter->fmt[i] = '\0';
+		trace_seq_vprintf(&iter->seq, iter->fmt, ap);
+
+		/*
+		 * If iter->seq is full, the above call no longer guarantees
+		 * that ap is in sync with fmt processing, and further calls
+		 * to va_arg() can return wrong positional arguments.
+		 *
+		 * Ensure that ap is no longer used in this case.
+		 */
+		if (iter->seq.full) {
+			p = "";
+			break;
+		}
+
+		if (star)
+			len = va_arg(ap, int);
+
+		/* The ap now points to the string data of the %s */
+		str = va_arg(ap, const char *);
+
+		/*
+		 * If you hit this warning, it is likely that the
+		 * trace event in question used %s on a string that
+		 * was saved at the time of the event, but may not be
+		 * around when the trace is read. Use __string(),
+		 * __assign_str() and __get_str() helpers in the TRACE_EVENT()
+		 * instead. See samples/trace_events/trace-events-sample.h
+		 * for reference.
+		 */
+		if (WARN_ONCE(!trace_safe_str(iter, str, star, len),
+			      "fmt: '%s' current_buffer: '%s'",
+			      fmt, show_buffer(&iter->seq))) {
+			int ret;
+
+			/* Try to safely read the string */
+			if (star) {
+				if (len + 1 > iter->fmt_size)
+					len = iter->fmt_size - 1;
+				if (len < 0)
+					len = 0;
+				ret = copy_from_kernel_nofault(iter->fmt, str, len);
+				iter->fmt[len] = 0;
+				star = false;
+			} else {
+				ret = strncpy_from_kernel_nofault(iter->fmt, str,
+								  iter->fmt_size);
+			}
+			if (ret < 0)
+				trace_seq_printf(&iter->seq, "(0x%px)", str);
+			else
+				trace_seq_printf(&iter->seq, "(0x%px:%s)",
+						 str, iter->fmt);
+			str = "[UNSAFE-MEMORY]";
+			strcpy(iter->fmt, "%s");
+		} else {
+			strncpy(iter->fmt, p + i, j + 1);
+			iter->fmt[j+1] = '\0';
+		}
+		if (star)
+			trace_seq_printf(&iter->seq, iter->fmt, len, str);
+		else
+			trace_seq_printf(&iter->seq, iter->fmt, str);
+
+		p += i + j + 1;
+	}
+ print:
+	if (*p)
+		trace_seq_vprintf(&iter->seq, p, ap);
+}
+
+const char *trace_event_format(struct trace_iterator *iter, const char *fmt)
+{
+	const char *p, *new_fmt;
+	char *q;
+
+	if (WARN_ON_ONCE(!fmt))
+		return fmt;
+
+	if (!iter->tr || iter->tr->trace_flags & TRACE_ITER_HASH_PTR)
+		return fmt;
+
+	p = fmt;
+	new_fmt = q = iter->fmt;
+	while (*p) {
+		if (unlikely(q - new_fmt + 3 > iter->fmt_size)) {
+			if (!trace_iter_expand_format(iter))
+				return fmt;
+
+			q += iter->fmt - new_fmt;
+			new_fmt = iter->fmt;
+		}
+
+		*q++ = *p++;
+
+		/* Replace %p with %px */
+		if (p[-1] == '%') {
+			if (p[0] == '%') {
+				*q++ = *p++;
+			} else if (p[0] == 'p' && !isalnum(p[1])) {
+				*q++ = *p++;
+				*q++ = 'x';
+			}
+		}
+	}
+	*q = '\0';
+
+	return new_fmt;
+}
+
+#define STATIC_TEMP_BUF_SIZE	128
+static char static_temp_buf[STATIC_TEMP_BUF_SIZE] __aligned(4);
+
+/* Find the next real entry, without updating the iterator itself */
+struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
+					  int *ent_cpu, u64 *ent_ts)
+{
+	/* __find_next_entry will reset ent_size */
+	int ent_size = iter->ent_size;
+	struct trace_entry *entry;
+
+	/*
+	 * If called from ftrace_dump(), then the iter->temp buffer
+	 * will be the static_temp_buf and not created from kmalloc.
+	 * If the entry size is greater than the buffer, we can
+	 * not save it. Just return NULL in that case. This is only
+	 * used to add markers when two consecutive events' time
+	 * stamps have a large delta. See trace_print_lat_context()
+	 */
+	if (iter->temp == static_temp_buf &&
+	    STATIC_TEMP_BUF_SIZE < ent_size)
+		return NULL;
+
+	/*
+	 * The __find_next_entry() may call peek_next_entry(), which may
+	 * call ring_buffer_peek() that may make the contents of iter->ent
+	 * undefined. Need to copy iter->ent now.
+	 */
+	if (iter->ent && iter->ent != iter->temp) {
+		if ((!iter->temp || iter->temp_size < iter->ent_size) &&
+		    !WARN_ON_ONCE(iter->temp == static_temp_buf)) {
+			void *temp;
+			temp = kmalloc(iter->ent_size, GFP_KERNEL);
+			if (!temp)
+				return NULL;
+			kfree(iter->temp);
+			iter->temp = temp;
+			iter->temp_size = iter->ent_size;
+		}
+		memcpy(iter->temp, iter->ent, iter->ent_size);
+		iter->ent = iter->temp;
+	}
+	entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts);
+	/* Put back the original ent_size */
+	iter->ent_size = ent_size;
+
+	return entry;
+}
+
+/* Find the next real entry, and increment the iterator to the next entry */
+void *trace_find_next_entry_inc(struct trace_iterator *iter)
+{
+	iter->ent = __find_next_entry(iter, &iter->cpu,
+				      &iter->lost_events, &iter->ts);
+
+	if (iter->ent)
+		trace_iterator_increment(iter);
+
+	return iter->ent ? iter : NULL;
+}
+
+static void trace_consume(struct trace_iterator *iter)
+{
+	ring_buffer_consume(iter->array_buffer->buffer, iter->cpu, &iter->ts,
+			    &iter->lost_events);
+}
+
+static void *s_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct trace_iterator *iter = m->private;
+	int i = (int)*pos;
+	void *ent;
+
+	WARN_ON_ONCE(iter->leftover);
+
+	(*pos)++;
+
+	/* can't go backwards */
+	if (iter->idx > i)
+		return NULL;
+
+	if (iter->idx < 0)
+		ent = trace_find_next_entry_inc(iter);
+	else
+		ent = iter;
+
+	while (ent && iter->idx < i)
+		ent = trace_find_next_entry_inc(iter);
+
+	iter->pos = *pos;
+
+	return ent;
+}
+
+void tracing_iter_reset(struct trace_iterator *iter, int cpu)
+{
+	struct ring_buffer_iter *buf_iter;
+	unsigned long entries = 0;
+	u64 ts;
+
+	per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = 0;
+
+	buf_iter = trace_buffer_iter(iter, cpu);
+	if (!buf_iter)
+		return;
+
+	ring_buffer_iter_reset(buf_iter);
+
+	/*
+	 * We could have the case with the max latency tracers
+	 * that a reset never took place on a cpu. This is evident
+	 * by the timestamp being before the start of the buffer.
+	 */
+	while (ring_buffer_iter_peek(buf_iter, &ts)) {
+		if (ts >= iter->array_buffer->time_start)
+			break;
+		entries++;
+		ring_buffer_iter_advance(buf_iter);
+	}
+
+	per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = entries;
+}
+
+/*
+ * The current tracer is copied to avoid a global locking
+ * all around.
+ */
+static void *s_start(struct seq_file *m, loff_t *pos)
+{
+	struct trace_iterator *iter = m->private;
+	struct trace_array *tr = iter->tr;
+	int cpu_file = iter->cpu_file;
+	void *p = NULL;
+	loff_t l = 0;
+	int cpu;
+
+	/*
+	 * copy the tracer to avoid using a global lock all around.
+	 * iter->trace is a copy of current_trace, the pointer to the
+	 * name may be used instead of a strcmp(), as iter->trace->name
+	 * will point to the same string as current_trace->name.
+	 */
+	mutex_lock(&trace_types_lock);
+	if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name)) {
+		/* Close iter->trace before switching to the new current tracer */
+		if (iter->trace->close)
+			iter->trace->close(iter);
+		*iter->trace = *tr->current_trace;
+		/* Reopen the new current tracer */
+		if (iter->trace->open)
+			iter->trace->open(iter);
+	}
+	mutex_unlock(&trace_types_lock);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (iter->snapshot && iter->trace->use_max_tr)
+		return ERR_PTR(-EBUSY);
+#endif
+
+	if (*pos != iter->pos) {
+		iter->ent = NULL;
+		iter->cpu = 0;
+		iter->idx = -1;
+
+		if (cpu_file == RING_BUFFER_ALL_CPUS) {
+			for_each_tracing_cpu(cpu)
+				tracing_iter_reset(iter, cpu);
+		} else
+			tracing_iter_reset(iter, cpu_file);
+
+		iter->leftover = 0;
+		for (p = iter; p && l < *pos; p = s_next(m, p, &l))
+			;
+
+	} else {
+		/*
+		 * If we overflowed the seq_file before, then we want
+		 * to just reuse the trace_seq buffer again.
+		 */
+		if (iter->leftover)
+			p = iter;
+		else {
+			l = *pos - 1;
+			p = s_next(m, p, &l);
+		}
+	}
+
+	trace_event_read_lock();
+	trace_access_lock(cpu_file);
+	return p;
+}
+
+static void s_stop(struct seq_file *m, void *p)
+{
+	struct trace_iterator *iter = m->private;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (iter->snapshot && iter->trace->use_max_tr)
+		return;
+#endif
+
+	trace_access_unlock(iter->cpu_file);
+	trace_event_read_unlock();
+}
+
+static void
+get_total_entries_cpu(struct array_buffer *buf, unsigned long *total,
+		      unsigned long *entries, int cpu)
+{
+	unsigned long count;
+
+	count = ring_buffer_entries_cpu(buf->buffer, cpu);
+	/*
+	 * If this buffer has skipped entries, then we hold all
+	 * entries for the trace and we need to ignore the
+	 * ones before the time stamp.
+	 */
+	if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
+		count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
+		/* total is the same as the entries */
+		*total = count;
+	} else
+		*total = count +
+			ring_buffer_overrun_cpu(buf->buffer, cpu);
+	*entries = count;
+}
+
+static void
+get_total_entries(struct array_buffer *buf,
+		  unsigned long *total, unsigned long *entries)
+{
+	unsigned long t, e;
+	int cpu;
+
+	*total = 0;
+	*entries = 0;
+
+	for_each_tracing_cpu(cpu) {
+		get_total_entries_cpu(buf, &t, &e, cpu);
+		*total += t;
+		*entries += e;
+	}
+}
+
+unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu)
+{
+	unsigned long total, entries;
+
+	if (!tr)
+		tr = &global_trace;
+
+	get_total_entries_cpu(&tr->array_buffer, &total, &entries, cpu);
+
+	return entries;
+}
+
+unsigned long trace_total_entries(struct trace_array *tr)
+{
+	unsigned long total, entries;
+
+	if (!tr)
+		tr = &global_trace;
+
+	get_total_entries(&tr->array_buffer, &total, &entries);
+
+	return entries;
+}
+
+static void print_lat_help_header(struct seq_file *m)
+{
+	seq_puts(m, "#                    _------=> CPU#            \n"
+		    "#                   / _-----=> irqs-off/BH-disabled\n"
+		    "#                  | / _----=> need-resched    \n"
+		    "#                  || / _---=> hardirq/softirq \n"
+		    "#                  ||| / _--=> preempt-depth   \n"
+		    "#                  |||| / _-=> migrate-disable \n"
+		    "#                  ||||| /     delay           \n"
+		    "#  cmd     pid     |||||| time  |   caller     \n"
+		    "#     \\   /        ||||||  \\    |    /       \n");
+}
+
+static void print_event_info(struct array_buffer *buf, struct seq_file *m)
+{
+	unsigned long total;
+	unsigned long entries;
+
+	get_total_entries(buf, &total, &entries);
+	seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu   #P:%d\n",
+		   entries, total, num_online_cpus());
+	seq_puts(m, "#\n");
+}
+
+static void print_func_help_header(struct array_buffer *buf, struct seq_file *m,
+				   unsigned int flags)
+{
+	bool tgid = flags & TRACE_ITER_RECORD_TGID;
+
+	print_event_info(buf, m);
+
+	seq_printf(m, "#           TASK-PID    %s CPU#     TIMESTAMP  FUNCTION\n", tgid ? "   TGID   " : "");
+	seq_printf(m, "#              | |      %s   |         |         |\n",      tgid ? "     |    " : "");
+}
+
+static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file *m,
+				       unsigned int flags)
+{
+	bool tgid = flags & TRACE_ITER_RECORD_TGID;
+	static const char space[] = "            ";
+	int prec = tgid ? 12 : 2;
+
+	print_event_info(buf, m);
+
+	seq_printf(m, "#                            %.*s  _-----=> irqs-off/BH-disabled\n", prec, space);
+	seq_printf(m, "#                            %.*s / _----=> need-resched\n", prec, space);
+	seq_printf(m, "#                            %.*s| / _---=> hardirq/softirq\n", prec, space);
+	seq_printf(m, "#                            %.*s|| / _--=> preempt-depth\n", prec, space);
+	seq_printf(m, "#                            %.*s||| / _-=> migrate-disable\n", prec, space);
+	seq_printf(m, "#                            %.*s|||| /     delay\n", prec, space);
+	seq_printf(m, "#           TASK-PID  %.*s CPU#  |||||  TIMESTAMP  FUNCTION\n", prec, "     TGID   ");
+	seq_printf(m, "#              | |    %.*s   |   |||||     |         |\n", prec, "       |    ");
+}
+
+void
+print_trace_header(struct seq_file *m, struct trace_iterator *iter)
+{
+	unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
+	struct array_buffer *buf = iter->array_buffer;
+	struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
+	struct tracer *type = iter->trace;
+	unsigned long entries;
+	unsigned long total;
+	const char *name = type->name;
+
+	get_total_entries(buf, &total, &entries);
+
+	seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
+		   name, UTS_RELEASE);
+	seq_puts(m, "# -----------------------------------"
+		 "---------------------------------\n");
+	seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
+		   " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
+		   nsecs_to_usecs(data->saved_latency),
+		   entries,
+		   total,
+		   buf->cpu,
+		   preempt_model_none()      ? "server" :
+		   preempt_model_voluntary() ? "desktop" :
+		   preempt_model_full()      ? "preempt" :
+		   preempt_model_rt()        ? "preempt_rt" :
+		   "unknown",
+		   /* These are reserved for later use */
+		   0, 0, 0, 0);
+#ifdef CONFIG_SMP
+	seq_printf(m, " #P:%d)\n", num_online_cpus());
+#else
+	seq_puts(m, ")\n");
+#endif
+	seq_puts(m, "#    -----------------\n");
+	seq_printf(m, "#    | task: %.16s-%d "
+		   "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
+		   data->comm, data->pid,
+		   from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
+		   data->policy, data->rt_priority);
+	seq_puts(m, "#    -----------------\n");
+
+	if (data->critical_start) {
+		seq_puts(m, "#  => started at: ");
+		seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
+		trace_print_seq(m, &iter->seq);
+		seq_puts(m, "\n#  => ended at:   ");
+		seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
+		trace_print_seq(m, &iter->seq);
+		seq_puts(m, "\n#\n");
+	}
+
+	seq_puts(m, "#\n");
+}
+
+static void test_cpu_buff_start(struct trace_iterator *iter)
+{
+	struct trace_seq *s = &iter->seq;
+	struct trace_array *tr = iter->tr;
+
+	if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
+		return;
+
+	if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
+		return;
+
+	if (cpumask_available(iter->started) &&
+	    cpumask_test_cpu(iter->cpu, iter->started))
+		return;
+
+	if (per_cpu_ptr(iter->array_buffer->data, iter->cpu)->skipped_entries)
+		return;
+
+	if (cpumask_available(iter->started))
+		cpumask_set_cpu(iter->cpu, iter->started);
+
+	/* Don't print started cpu buffer for the first entry of the trace */
+	if (iter->idx > 1)
+		trace_seq_printf(s, "##### CPU %u buffer started ####\n",
+				iter->cpu);
+}
+
+static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
+	struct trace_entry *entry;
+	struct trace_event *event;
+
+	entry = iter->ent;
+
+	test_cpu_buff_start(iter);
+
+	event = ftrace_find_event(entry->type);
+
+	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
+		if (iter->iter_flags & TRACE_FILE_LAT_FMT)
+			trace_print_lat_context(iter);
+		else
+			trace_print_context(iter);
+	}
+
+	if (trace_seq_has_overflowed(s))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	if (event)
+		return event->funcs->trace(iter, sym_flags, event);
+
+	trace_seq_printf(s, "Unknown type %d\n", entry->type);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *entry;
+	struct trace_event *event;
+
+	entry = iter->ent;
+
+	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
+		trace_seq_printf(s, "%d %d %llu ",
+				 entry->pid, iter->cpu, iter->ts);
+
+	if (trace_seq_has_overflowed(s))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	event = ftrace_find_event(entry->type);
+	if (event)
+		return event->funcs->raw(iter, 0, event);
+
+	trace_seq_printf(s, "%d ?\n", entry->type);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	unsigned char newline = '\n';
+	struct trace_entry *entry;
+	struct trace_event *event;
+
+	entry = iter->ent;
+
+	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
+		SEQ_PUT_HEX_FIELD(s, entry->pid);
+		SEQ_PUT_HEX_FIELD(s, iter->cpu);
+		SEQ_PUT_HEX_FIELD(s, iter->ts);
+		if (trace_seq_has_overflowed(s))
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	event = ftrace_find_event(entry->type);
+	if (event) {
+		enum print_line_t ret = event->funcs->hex(iter, 0, event);
+		if (ret != TRACE_TYPE_HANDLED)
+			return ret;
+	}
+
+	SEQ_PUT_FIELD(s, newline);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *entry;
+	struct trace_event *event;
+
+	entry = iter->ent;
+
+	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
+		SEQ_PUT_FIELD(s, entry->pid);
+		SEQ_PUT_FIELD(s, iter->cpu);
+		SEQ_PUT_FIELD(s, iter->ts);
+		if (trace_seq_has_overflowed(s))
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	event = ftrace_find_event(entry->type);
+	return event ? event->funcs->binary(iter, 0, event) :
+		TRACE_TYPE_HANDLED;
+}
+
+int trace_empty(struct trace_iterator *iter)
+{
+	struct ring_buffer_iter *buf_iter;
+	int cpu;
+
+	/* If we are looking at one CPU buffer, only check that one */
+	if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
+		cpu = iter->cpu_file;
+		buf_iter = trace_buffer_iter(iter, cpu);
+		if (buf_iter) {
+			if (!ring_buffer_iter_empty(buf_iter))
+				return 0;
+		} else {
+			if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
+				return 0;
+		}
+		return 1;
+	}
+
+	for_each_tracing_cpu(cpu) {
+		buf_iter = trace_buffer_iter(iter, cpu);
+		if (buf_iter) {
+			if (!ring_buffer_iter_empty(buf_iter))
+				return 0;
+		} else {
+			if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
+				return 0;
+		}
+	}
+
+	return 1;
+}
+
+/*  Called with trace_event_read_lock() held. */
+enum print_line_t print_trace_line(struct trace_iterator *iter)
+{
+	struct trace_array *tr = iter->tr;
+	unsigned long trace_flags = tr->trace_flags;
+	enum print_line_t ret;
+
+	if (iter->lost_events) {
+		if (iter->lost_events == (unsigned long)-1)
+			trace_seq_printf(&iter->seq, "CPU:%d [LOST EVENTS]\n",
+					 iter->cpu);
+		else
+			trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
+					 iter->cpu, iter->lost_events);
+		if (trace_seq_has_overflowed(&iter->seq))
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	if (iter->trace && iter->trace->print_line) {
+		ret = iter->trace->print_line(iter);
+		if (ret != TRACE_TYPE_UNHANDLED)
+			return ret;
+	}
+
+	if (iter->ent->type == TRACE_BPUTS &&
+			trace_flags & TRACE_ITER_PRINTK &&
+			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
+		return trace_print_bputs_msg_only(iter);
+
+	if (iter->ent->type == TRACE_BPRINT &&
+			trace_flags & TRACE_ITER_PRINTK &&
+			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
+		return trace_print_bprintk_msg_only(iter);
+
+	if (iter->ent->type == TRACE_PRINT &&
+			trace_flags & TRACE_ITER_PRINTK &&
+			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
+		return trace_print_printk_msg_only(iter);
+
+	if (trace_flags & TRACE_ITER_BIN)
+		return print_bin_fmt(iter);
+
+	if (trace_flags & TRACE_ITER_HEX)
+		return print_hex_fmt(iter);
+
+	if (trace_flags & TRACE_ITER_RAW)
+		return print_raw_fmt(iter);
+
+	return print_trace_fmt(iter);
+}
+
+void trace_latency_header(struct seq_file *m)
+{
+	struct trace_iterator *iter = m->private;
+	struct trace_array *tr = iter->tr;
+
+	/* print nothing if the buffers are empty */
+	if (trace_empty(iter))
+		return;
+
+	if (iter->iter_flags & TRACE_FILE_LAT_FMT)
+		print_trace_header(m, iter);
+
+	if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
+		print_lat_help_header(m);
+}
+
+void trace_default_header(struct seq_file *m)
+{
+	struct trace_iterator *iter = m->private;
+	struct trace_array *tr = iter->tr;
+	unsigned long trace_flags = tr->trace_flags;
+
+	if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
+		return;
+
+	if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
+		/* print nothing if the buffers are empty */
+		if (trace_empty(iter))
+			return;
+		print_trace_header(m, iter);
+		if (!(trace_flags & TRACE_ITER_VERBOSE))
+			print_lat_help_header(m);
+	} else {
+		if (!(trace_flags & TRACE_ITER_VERBOSE)) {
+			if (trace_flags & TRACE_ITER_IRQ_INFO)
+				print_func_help_header_irq(iter->array_buffer,
+							   m, trace_flags);
+			else
+				print_func_help_header(iter->array_buffer, m,
+						       trace_flags);
+		}
+	}
+}
+
+static void test_ftrace_alive(struct seq_file *m)
+{
+	if (!ftrace_is_dead())
+		return;
+	seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
+		    "#          MAY BE MISSING FUNCTION EVENTS\n");
+}
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+static void show_snapshot_main_help(struct seq_file *m)
+{
+	seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
+		    "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
+		    "#                      Takes a snapshot of the main buffer.\n"
+		    "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
+		    "#                      (Doesn't have to be '2' works with any number that\n"
+		    "#                       is not a '0' or '1')\n");
+}
+
+static void show_snapshot_percpu_help(struct seq_file *m)
+{
+	seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
+#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
+	seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
+		    "#                      Takes a snapshot of the main buffer for this cpu.\n");
+#else
+	seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
+		    "#                     Must use main snapshot file to allocate.\n");
+#endif
+	seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
+		    "#                      (Doesn't have to be '2' works with any number that\n"
+		    "#                       is not a '0' or '1')\n");
+}
+
+static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
+{
+	if (iter->tr->allocated_snapshot)
+		seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
+	else
+		seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
+
+	seq_puts(m, "# Snapshot commands:\n");
+	if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
+		show_snapshot_main_help(m);
+	else
+		show_snapshot_percpu_help(m);
+}
+#else
+/* Should never be called */
+static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
+#endif
+
+static int s_show(struct seq_file *m, void *v)
+{
+	struct trace_iterator *iter = v;
+	int ret;
+
+	if (iter->ent == NULL) {
+		if (iter->tr) {
+			seq_printf(m, "# tracer: %s\n", iter->trace->name);
+			seq_puts(m, "#\n");
+			test_ftrace_alive(m);
+		}
+		if (iter->snapshot && trace_empty(iter))
+			print_snapshot_help(m, iter);
+		else if (iter->trace && iter->trace->print_header)
+			iter->trace->print_header(m);
+		else
+			trace_default_header(m);
+
+	} else if (iter->leftover) {
+		/*
+		 * If we filled the seq_file buffer earlier, we
+		 * want to just show it now.
+		 */
+		ret = trace_print_seq(m, &iter->seq);
+
+		/* ret should this time be zero, but you never know */
+		iter->leftover = ret;
+
+	} else {
+		ret = print_trace_line(iter);
+		if (ret == TRACE_TYPE_PARTIAL_LINE) {
+			iter->seq.full = 0;
+			trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
+		}
+		ret = trace_print_seq(m, &iter->seq);
+		/*
+		 * If we overflow the seq_file buffer, then it will
+		 * ask us for this data again at start up.
+		 * Use that instead.
+		 *  ret is 0 if seq_file write succeeded.
+		 *        -1 otherwise.
+		 */
+		iter->leftover = ret;
+	}
+
+	return 0;
+}
+
+/*
+ * Should be used after trace_array_get(), trace_types_lock
+ * ensures that i_cdev was already initialized.
+ */
+static inline int tracing_get_cpu(struct inode *inode)
+{
+	if (inode->i_cdev) /* See trace_create_cpu_file() */
+		return (long)inode->i_cdev - 1;
+	return RING_BUFFER_ALL_CPUS;
+}
+
+static const struct seq_operations tracer_seq_ops = {
+	.start		= s_start,
+	.next		= s_next,
+	.stop		= s_stop,
+	.show		= s_show,
+};
+
+static struct trace_iterator *
+__tracing_open(struct inode *inode, struct file *file, bool snapshot)
+{
+	struct trace_array *tr = inode->i_private;
+	struct trace_iterator *iter;
+	int cpu;
+
+	if (tracing_disabled)
+		return ERR_PTR(-ENODEV);
+
+	iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
+	if (!iter)
+		return ERR_PTR(-ENOMEM);
+
+	iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
+				    GFP_KERNEL);
+	if (!iter->buffer_iter)
+		goto release;
+
+	/*
+	 * trace_find_next_entry() may need to save off iter->ent.
+	 * It will place it into the iter->temp buffer. As most
+	 * events are less than 128, allocate a buffer of that size.
+	 * If one is greater, then trace_find_next_entry() will
+	 * allocate a new buffer to adjust for the bigger iter->ent.
+	 * It's not critical if it fails to get allocated here.
+	 */
+	iter->temp = kmalloc(128, GFP_KERNEL);
+	if (iter->temp)
+		iter->temp_size = 128;
+
+	/*
+	 * trace_event_printf() may need to modify given format
+	 * string to replace %p with %px so that it shows real address
+	 * instead of hash value. However, that is only for the event
+	 * tracing, other tracer may not need. Defer the allocation
+	 * until it is needed.
+	 */
+	iter->fmt = NULL;
+	iter->fmt_size = 0;
+
+	/*
+	 * We make a copy of the current tracer to avoid concurrent
+	 * changes on it while we are reading.
+	 */
+	mutex_lock(&trace_types_lock);
+	iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
+	if (!iter->trace)
+		goto fail;
+
+	*iter->trace = *tr->current_trace;
+
+	if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
+		goto fail;
+
+	iter->tr = tr;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	/* Currently only the top directory has a snapshot */
+	if (tr->current_trace->print_max || snapshot)
+		iter->array_buffer = &tr->max_buffer;
+	else
+#endif
+		iter->array_buffer = &tr->array_buffer;
+	iter->snapshot = snapshot;
+	iter->pos = -1;
+	iter->cpu_file = tracing_get_cpu(inode);
+	mutex_init(&iter->mutex);
+
+	/* Notify the tracer early; before we stop tracing. */
+	if (iter->trace->open)
+		iter->trace->open(iter);
+
+	/* Annotate start of buffers if we had overruns */
+	if (ring_buffer_overruns(iter->array_buffer->buffer))
+		iter->iter_flags |= TRACE_FILE_ANNOTATE;
+
+	/* Output in nanoseconds only if we are using a clock in nanoseconds. */
+	if (trace_clocks[tr->clock_id].in_ns)
+		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
+
+	/*
+	 * If pause-on-trace is enabled, then stop the trace while
+	 * dumping, unless this is the "snapshot" file
+	 */
+	if (!iter->snapshot && (tr->trace_flags & TRACE_ITER_PAUSE_ON_TRACE))
+		tracing_stop_tr(tr);
+
+	if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
+		for_each_tracing_cpu(cpu) {
+			iter->buffer_iter[cpu] =
+				ring_buffer_read_prepare(iter->array_buffer->buffer,
+							 cpu, GFP_KERNEL);
+		}
+		ring_buffer_read_prepare_sync();
+		for_each_tracing_cpu(cpu) {
+			ring_buffer_read_start(iter->buffer_iter[cpu]);
+			tracing_iter_reset(iter, cpu);
+		}
+	} else {
+		cpu = iter->cpu_file;
+		iter->buffer_iter[cpu] =
+			ring_buffer_read_prepare(iter->array_buffer->buffer,
+						 cpu, GFP_KERNEL);
+		ring_buffer_read_prepare_sync();
+		ring_buffer_read_start(iter->buffer_iter[cpu]);
+		tracing_iter_reset(iter, cpu);
+	}
+
+	mutex_unlock(&trace_types_lock);
+
+	return iter;
+
+ fail:
+	mutex_unlock(&trace_types_lock);
+	kfree(iter->trace);
+	kfree(iter->temp);
+	kfree(iter->buffer_iter);
+release:
+	seq_release_private(inode, file);
+	return ERR_PTR(-ENOMEM);
+}
+
+int tracing_open_generic(struct inode *inode, struct file *filp)
+{
+	int ret;
+
+	ret = tracing_check_open_get_tr(NULL);
+	if (ret)
+		return ret;
+
+	filp->private_data = inode->i_private;
+	return 0;
+}
+
+bool tracing_is_disabled(void)
+{
+	return (tracing_disabled) ? true: false;
+}
+
+/*
+ * Open and update trace_array ref count.
+ * Must have the current trace_array passed to it.
+ */
+int tracing_open_generic_tr(struct inode *inode, struct file *filp)
+{
+	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	filp->private_data = inode->i_private;
+
+	return 0;
+}
+
+/*
+ * The private pointer of the inode is the trace_event_file.
+ * Update the tr ref count associated to it.
+ */
+int tracing_open_file_tr(struct inode *inode, struct file *filp)
+{
+	struct trace_event_file *file = inode->i_private;
+	int ret;
+
+	ret = tracing_check_open_get_tr(file->tr);
+	if (ret)
+		return ret;
+
+	mutex_lock(&event_mutex);
+
+	/* Fail if the file is marked for removal */
+	if (file->flags & EVENT_FILE_FL_FREED) {
+		trace_array_put(file->tr);
+		ret = -ENODEV;
+	} else {
+		event_file_get(file);
+	}
+
+	mutex_unlock(&event_mutex);
+	if (ret)
+		return ret;
+
+	filp->private_data = inode->i_private;
+
+	return 0;
+}
+
+int tracing_release_file_tr(struct inode *inode, struct file *filp)
+{
+	struct trace_event_file *file = inode->i_private;
+
+	trace_array_put(file->tr);
+	event_file_put(file);
+
+	return 0;
+}
+
+int tracing_single_release_file_tr(struct inode *inode, struct file *filp)
+{
+	tracing_release_file_tr(inode, filp);
+	return single_release(inode, filp);
+}
+
+static int tracing_mark_open(struct inode *inode, struct file *filp)
+{
+	stream_open(inode, filp);
+	return tracing_open_generic_tr(inode, filp);
+}
+
+static int tracing_release(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	struct seq_file *m = file->private_data;
+	struct trace_iterator *iter;
+	int cpu;
+
+	if (!(file->f_mode & FMODE_READ)) {
+		trace_array_put(tr);
+		return 0;
+	}
+
+	/* Writes do not use seq_file */
+	iter = m->private;
+	mutex_lock(&trace_types_lock);
+
+	for_each_tracing_cpu(cpu) {
+		if (iter->buffer_iter[cpu])
+			ring_buffer_read_finish(iter->buffer_iter[cpu]);
+	}
+
+	if (iter->trace && iter->trace->close)
+		iter->trace->close(iter);
+
+	if (!iter->snapshot && tr->stop_count)
+		/* reenable tracing if it was previously enabled */
+		tracing_start_tr(tr);
+
+	__trace_array_put(tr);
+
+	mutex_unlock(&trace_types_lock);
+
+	mutex_destroy(&iter->mutex);
+	free_cpumask_var(iter->started);
+	kfree(iter->fmt);
+	kfree(iter->temp);
+	kfree(iter->trace);
+	kfree(iter->buffer_iter);
+	seq_release_private(inode, file);
+
+	return 0;
+}
+
+static int tracing_release_generic_tr(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+
+	trace_array_put(tr);
+	return 0;
+}
+
+static int tracing_single_release_tr(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+
+	trace_array_put(tr);
+
+	return single_release(inode, file);
+}
+
+static int tracing_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	struct trace_iterator *iter;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	/* If this file was open for write, then erase contents */
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+		int cpu = tracing_get_cpu(inode);
+		struct array_buffer *trace_buf = &tr->array_buffer;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+		if (tr->current_trace->print_max)
+			trace_buf = &tr->max_buffer;
+#endif
+
+		if (cpu == RING_BUFFER_ALL_CPUS)
+			tracing_reset_online_cpus(trace_buf);
+		else
+			tracing_reset_cpu(trace_buf, cpu);
+	}
+
+	if (file->f_mode & FMODE_READ) {
+		iter = __tracing_open(inode, file, false);
+		if (IS_ERR(iter))
+			ret = PTR_ERR(iter);
+		else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
+			iter->iter_flags |= TRACE_FILE_LAT_FMT;
+	}
+
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
+}
+
+/*
+ * Some tracers are not suitable for instance buffers.
+ * A tracer is always available for the global array (toplevel)
+ * or if it explicitly states that it is.
+ */
+static bool
+trace_ok_for_array(struct tracer *t, struct trace_array *tr)
+{
+	return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
+}
+
+/* Find the next tracer that this trace array may use */
+static struct tracer *
+get_tracer_for_array(struct trace_array *tr, struct tracer *t)
+{
+	while (t && !trace_ok_for_array(t, tr))
+		t = t->next;
+
+	return t;
+}
+
+static void *
+t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct trace_array *tr = m->private;
+	struct tracer *t = v;
+
+	(*pos)++;
+
+	if (t)
+		t = get_tracer_for_array(tr, t->next);
+
+	return t;
+}
+
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+	struct trace_array *tr = m->private;
+	struct tracer *t;
+	loff_t l = 0;
+
+	mutex_lock(&trace_types_lock);
+
+	t = get_tracer_for_array(tr, trace_types);
+	for (; t && l < *pos; t = t_next(m, t, &l))
+			;
+
+	return t;
+}
+
+static void t_stop(struct seq_file *m, void *p)
+{
+	mutex_unlock(&trace_types_lock);
+}
+
+static int t_show(struct seq_file *m, void *v)
+{
+	struct tracer *t = v;
+
+	if (!t)
+		return 0;
+
+	seq_puts(m, t->name);
+	if (t->next)
+		seq_putc(m, ' ');
+	else
+		seq_putc(m, '\n');
+
+	return 0;
+}
+
+static const struct seq_operations show_traces_seq_ops = {
+	.start		= t_start,
+	.next		= t_next,
+	.stop		= t_stop,
+	.show		= t_show,
+};
+
+static int show_traces_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	struct seq_file *m;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	ret = seq_open(file, &show_traces_seq_ops);
+	if (ret) {
+		trace_array_put(tr);
+		return ret;
+	}
+
+	m = file->private_data;
+	m->private = tr;
+
+	return 0;
+}
+
+static int show_traces_release(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+
+	trace_array_put(tr);
+	return seq_release(inode, file);
+}
+
+static ssize_t
+tracing_write_stub(struct file *filp, const char __user *ubuf,
+		   size_t count, loff_t *ppos)
+{
+	return count;
+}
+
+loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
+{
+	int ret;
+
+	if (file->f_mode & FMODE_READ)
+		ret = seq_lseek(file, offset, whence);
+	else
+		file->f_pos = ret = 0;
+
+	return ret;
+}
+
+static const struct file_operations tracing_fops = {
+	.open		= tracing_open,
+	.read		= seq_read,
+	.read_iter	= seq_read_iter,
+	.splice_read	= generic_file_splice_read,
+	.write		= tracing_write_stub,
+	.llseek		= tracing_lseek,
+	.release	= tracing_release,
+};
+
+static const struct file_operations show_traces_fops = {
+	.open		= show_traces_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= show_traces_release,
+};
+
+static ssize_t
+tracing_cpumask_read(struct file *filp, char __user *ubuf,
+		     size_t count, loff_t *ppos)
+{
+	struct trace_array *tr = file_inode(filp)->i_private;
+	char *mask_str;
+	int len;
+
+	len = snprintf(NULL, 0, "%*pb\n",
+		       cpumask_pr_args(tr->tracing_cpumask)) + 1;
+	mask_str = kmalloc(len, GFP_KERNEL);
+	if (!mask_str)
+		return -ENOMEM;
+
+	len = snprintf(mask_str, len, "%*pb\n",
+		       cpumask_pr_args(tr->tracing_cpumask));
+	if (len >= count) {
+		count = -EINVAL;
+		goto out_err;
+	}
+	count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
+
+out_err:
+	kfree(mask_str);
+
+	return count;
+}
+
+int tracing_set_cpumask(struct trace_array *tr,
+			cpumask_var_t tracing_cpumask_new)
+{
+	int cpu;
+
+	if (!tr)
+		return -EINVAL;
+
+	local_irq_disable();
+	arch_spin_lock(&tr->max_lock);
+	for_each_tracing_cpu(cpu) {
+		/*
+		 * Increase/decrease the disabled counter if we are
+		 * about to flip a bit in the cpumask:
+		 */
+		if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
+				!cpumask_test_cpu(cpu, tracing_cpumask_new)) {
+			atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
+			ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu);
+#ifdef CONFIG_TRACER_MAX_TRACE
+			ring_buffer_record_disable_cpu(tr->max_buffer.buffer, cpu);
+#endif
+		}
+		if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
+				cpumask_test_cpu(cpu, tracing_cpumask_new)) {
+			atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
+			ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu);
+#ifdef CONFIG_TRACER_MAX_TRACE
+			ring_buffer_record_enable_cpu(tr->max_buffer.buffer, cpu);
+#endif
+		}
+	}
+	arch_spin_unlock(&tr->max_lock);
+	local_irq_enable();
+
+	cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
+
+	return 0;
+}
+
+static ssize_t
+tracing_cpumask_write(struct file *filp, const char __user *ubuf,
+		      size_t count, loff_t *ppos)
+{
+	struct trace_array *tr = file_inode(filp)->i_private;
+	cpumask_var_t tracing_cpumask_new;
+	int err;
+
+	if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
+		return -ENOMEM;
+
+	err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
+	if (err)
+		goto err_free;
+
+	err = tracing_set_cpumask(tr, tracing_cpumask_new);
+	if (err)
+		goto err_free;
+
+	free_cpumask_var(tracing_cpumask_new);
+
+	return count;
+
+err_free:
+	free_cpumask_var(tracing_cpumask_new);
+
+	return err;
+}
+
+static const struct file_operations tracing_cpumask_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= tracing_cpumask_read,
+	.write		= tracing_cpumask_write,
+	.release	= tracing_release_generic_tr,
+	.llseek		= generic_file_llseek,
+};
+
+static int tracing_trace_options_show(struct seq_file *m, void *v)
+{
+	struct tracer_opt *trace_opts;
+	struct trace_array *tr = m->private;
+	u32 tracer_flags;
+	int i;
+
+	mutex_lock(&trace_types_lock);
+	tracer_flags = tr->current_trace->flags->val;
+	trace_opts = tr->current_trace->flags->opts;
+
+	for (i = 0; trace_options[i]; i++) {
+		if (tr->trace_flags & (1 << i))
+			seq_printf(m, "%s\n", trace_options[i]);
+		else
+			seq_printf(m, "no%s\n", trace_options[i]);
+	}
+
+	for (i = 0; trace_opts[i].name; i++) {
+		if (tracer_flags & trace_opts[i].bit)
+			seq_printf(m, "%s\n", trace_opts[i].name);
+		else
+			seq_printf(m, "no%s\n", trace_opts[i].name);
+	}
+	mutex_unlock(&trace_types_lock);
+
+	return 0;
+}
+
+static int __set_tracer_option(struct trace_array *tr,
+			       struct tracer_flags *tracer_flags,
+			       struct tracer_opt *opts, int neg)
+{
+	struct tracer *trace = tracer_flags->trace;
+	int ret;
+
+	ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
+	if (ret)
+		return ret;
+
+	if (neg)
+		tracer_flags->val &= ~opts->bit;
+	else
+		tracer_flags->val |= opts->bit;
+	return 0;
+}
+
+/* Try to assign a tracer specific option */
+static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
+{
+	struct tracer *trace = tr->current_trace;
+	struct tracer_flags *tracer_flags = trace->flags;
+	struct tracer_opt *opts = NULL;
+	int i;
+
+	for (i = 0; tracer_flags->opts[i].name; i++) {
+		opts = &tracer_flags->opts[i];
+
+		if (strcmp(cmp, opts->name) == 0)
+			return __set_tracer_option(tr, trace->flags, opts, neg);
+	}
+
+	return -EINVAL;
+}
+
+/* Some tracers require overwrite to stay enabled */
+int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
+{
+	if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
+		return -1;
+
+	return 0;
+}
+
+int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
+{
+	int *map;
+
+	if ((mask == TRACE_ITER_RECORD_TGID) ||
+	    (mask == TRACE_ITER_RECORD_CMD))
+		lockdep_assert_held(&event_mutex);
+
+	/* do nothing if flag is already set */
+	if (!!(tr->trace_flags & mask) == !!enabled)
+		return 0;
+
+	/* Give the tracer a chance to approve the change */
+	if (tr->current_trace->flag_changed)
+		if (tr->current_trace->flag_changed(tr, mask, !!enabled))
+			return -EINVAL;
+
+	if (enabled)
+		tr->trace_flags |= mask;
+	else
+		tr->trace_flags &= ~mask;
+
+	if (mask == TRACE_ITER_RECORD_CMD)
+		trace_event_enable_cmd_record(enabled);
+
+	if (mask == TRACE_ITER_RECORD_TGID) {
+		if (!tgid_map) {
+			tgid_map_max = pid_max;
+			map = kvcalloc(tgid_map_max + 1, sizeof(*tgid_map),
+				       GFP_KERNEL);
+
+			/*
+			 * Pairs with smp_load_acquire() in
+			 * trace_find_tgid_ptr() to ensure that if it observes
+			 * the tgid_map we just allocated then it also observes
+			 * the corresponding tgid_map_max value.
+			 */
+			smp_store_release(&tgid_map, map);
+		}
+		if (!tgid_map) {
+			tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
+			return -ENOMEM;
+		}
+
+		trace_event_enable_tgid_record(enabled);
+	}
+
+	if (mask == TRACE_ITER_EVENT_FORK)
+		trace_event_follow_fork(tr, enabled);
+
+	if (mask == TRACE_ITER_FUNC_FORK)
+		ftrace_pid_follow_fork(tr, enabled);
+
+	if (mask == TRACE_ITER_OVERWRITE) {
+		ring_buffer_change_overwrite(tr->array_buffer.buffer, enabled);
+#ifdef CONFIG_TRACER_MAX_TRACE
+		ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
+#endif
+	}
+
+	if (mask == TRACE_ITER_PRINTK) {
+		trace_printk_start_stop_comm(enabled);
+		trace_printk_control(enabled);
+	}
+
+	return 0;
+}
+
+int trace_set_options(struct trace_array *tr, char *option)
+{
+	char *cmp;
+	int neg = 0;
+	int ret;
+	size_t orig_len = strlen(option);
+	int len;
+
+	cmp = strstrip(option);
+
+	len = str_has_prefix(cmp, "no");
+	if (len)
+		neg = 1;
+
+	cmp += len;
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+
+	ret = match_string(trace_options, -1, cmp);
+	/* If no option could be set, test the specific tracer options */
+	if (ret < 0)
+		ret = set_tracer_option(tr, cmp, neg);
+	else
+		ret = set_tracer_flag(tr, 1 << ret, !neg);
+
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+
+	/*
+	 * If the first trailing whitespace is replaced with '\0' by strstrip,
+	 * turn it back into a space.
+	 */
+	if (orig_len > strlen(option))
+		option[strlen(option)] = ' ';
+
+	return ret;
+}
+
+static void __init apply_trace_boot_options(void)
+{
+	char *buf = trace_boot_options_buf;
+	char *option;
+
+	while (true) {
+		option = strsep(&buf, ",");
+
+		if (!option)
+			break;
+
+		if (*option)
+			trace_set_options(&global_trace, option);
+
+		/* Put back the comma to allow this to be called again */
+		if (buf)
+			*(buf - 1) = ',';
+	}
+}
+
+static ssize_t
+tracing_trace_options_write(struct file *filp, const char __user *ubuf,
+			size_t cnt, loff_t *ppos)
+{
+	struct seq_file *m = filp->private_data;
+	struct trace_array *tr = m->private;
+	char buf[64];
+	int ret;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	ret = trace_set_options(tr, buf);
+	if (ret < 0)
+		return ret;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static int tracing_trace_options_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	ret = single_open(file, tracing_trace_options_show, inode->i_private);
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
+}
+
+static const struct file_operations tracing_iter_fops = {
+	.open		= tracing_trace_options_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= tracing_single_release_tr,
+	.write		= tracing_trace_options_write,
+};
+
+static const char readme_msg[] =
+	"tracing mini-HOWTO:\n\n"
+	"# echo 0 > tracing_on : quick way to disable tracing\n"
+	"# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
+	" Important files:\n"
+	"  trace\t\t\t- The static contents of the buffer\n"
+	"\t\t\t  To clear the buffer write into this file: echo > trace\n"
+	"  trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
+	"  current_tracer\t- function and latency tracers\n"
+	"  available_tracers\t- list of configured tracers for current_tracer\n"
+	"  error_log\t- error log for failed commands (that support it)\n"
+	"  buffer_size_kb\t- view and modify size of per cpu buffer\n"
+	"  buffer_total_size_kb  - view total size of all cpu buffers\n\n"
+	"  trace_clock\t\t- change the clock used to order events\n"
+	"       local:   Per cpu clock but may not be synced across CPUs\n"
+	"      global:   Synced across CPUs but slows tracing down.\n"
+	"     counter:   Not a clock, but just an increment\n"
+	"      uptime:   Jiffy counter from time of boot\n"
+	"        perf:   Same clock that perf events use\n"
+#ifdef CONFIG_X86_64
+	"     x86-tsc:   TSC cycle counter\n"
+#endif
+	"\n  timestamp_mode\t- view the mode used to timestamp events\n"
+	"       delta:   Delta difference against a buffer-wide timestamp\n"
+	"    absolute:   Absolute (standalone) timestamp\n"
+	"\n  trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
+	"\n  trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
+	"  tracing_cpumask\t- Limit which CPUs to trace\n"
+	"  instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
+	"\t\t\t  Remove sub-buffer with rmdir\n"
+	"  trace_options\t\t- Set format or modify how tracing happens\n"
+	"\t\t\t  Disable an option by prefixing 'no' to the\n"
+	"\t\t\t  option name\n"
+	"  saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
+#ifdef CONFIG_DYNAMIC_FTRACE
+	"\n  available_filter_functions - list of functions that can be filtered on\n"
+	"  set_ftrace_filter\t- echo function name in here to only trace these\n"
+	"\t\t\t  functions\n"
+	"\t     accepts: func_full_name or glob-matching-pattern\n"
+	"\t     modules: Can select a group via module\n"
+	"\t      Format: :mod:<module-name>\n"
+	"\t     example: echo :mod:ext3 > set_ftrace_filter\n"
+	"\t    triggers: a command to perform when function is hit\n"
+	"\t      Format: <function>:<trigger>[:count]\n"
+	"\t     trigger: traceon, traceoff\n"
+	"\t\t      enable_event:<system>:<event>\n"
+	"\t\t      disable_event:<system>:<event>\n"
+#ifdef CONFIG_STACKTRACE
+	"\t\t      stacktrace\n"
+#endif
+#ifdef CONFIG_TRACER_SNAPSHOT
+	"\t\t      snapshot\n"
+#endif
+	"\t\t      dump\n"
+	"\t\t      cpudump\n"
+	"\t     example: echo do_fault:traceoff > set_ftrace_filter\n"
+	"\t              echo do_trap:traceoff:3 > set_ftrace_filter\n"
+	"\t     The first one will disable tracing every time do_fault is hit\n"
+	"\t     The second will disable tracing at most 3 times when do_trap is hit\n"
+	"\t       The first time do trap is hit and it disables tracing, the\n"
+	"\t       counter will decrement to 2. If tracing is already disabled,\n"
+	"\t       the counter will not decrement. It only decrements when the\n"
+	"\t       trigger did work\n"
+	"\t     To remove trigger without count:\n"
+	"\t       echo '!<function>:<trigger> > set_ftrace_filter\n"
+	"\t     To remove trigger with a count:\n"
+	"\t       echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
+	"  set_ftrace_notrace\t- echo function name in here to never trace.\n"
+	"\t    accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
+	"\t    modules: Can select a group via module command :mod:\n"
+	"\t    Does not accept triggers\n"
+#endif /* CONFIG_DYNAMIC_FTRACE */
+#ifdef CONFIG_FUNCTION_TRACER
+	"  set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
+	"\t\t    (function)\n"
+	"  set_ftrace_notrace_pid\t- Write pid(s) to not function trace those pids\n"
+	"\t\t    (function)\n"
+#endif
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	"  set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
+	"  set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
+	"  max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
+#endif
+#ifdef CONFIG_TRACER_SNAPSHOT
+	"\n  snapshot\t\t- Like 'trace' but shows the content of the static\n"
+	"\t\t\t  snapshot buffer. Read the contents for more\n"
+	"\t\t\t  information\n"
+#endif
+#ifdef CONFIG_STACK_TRACER
+	"  stack_trace\t\t- Shows the max stack trace when active\n"
+	"  stack_max_size\t- Shows current max stack size that was traced\n"
+	"\t\t\t  Write into this file to reset the max size (trigger a\n"
+	"\t\t\t  new trace)\n"
+#ifdef CONFIG_DYNAMIC_FTRACE
+	"  stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
+	"\t\t\t  traces\n"
+#endif
+#endif /* CONFIG_STACK_TRACER */
+#ifdef CONFIG_DYNAMIC_EVENTS
+	"  dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
+	"\t\t\t  Write into this file to define/undefine new trace events.\n"
+#endif
+#ifdef CONFIG_KPROBE_EVENTS
+	"  kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
+	"\t\t\t  Write into this file to define/undefine new trace events.\n"
+#endif
+#ifdef CONFIG_UPROBE_EVENTS
+	"  uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
+	"\t\t\t  Write into this file to define/undefine new trace events.\n"
+#endif
+#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
+	"\t  accepts: event-definitions (one definition per line)\n"
+	"\t   Format: p[:[<group>/][<event>]] <place> [<args>]\n"
+	"\t           r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"
+#ifdef CONFIG_HIST_TRIGGERS
+	"\t           s:[synthetic/]<event> <field> [<field>]\n"
+#endif
+	"\t           e[:[<group>/][<event>]] <attached-group>.<attached-event> [<args>] [if <filter>]\n"
+	"\t           -:[<group>/][<event>]\n"
+#ifdef CONFIG_KPROBE_EVENTS
+	"\t    place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
+  "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n"
+#endif
+#ifdef CONFIG_UPROBE_EVENTS
+  "   place (uprobe): <path>:<offset>[%return][(ref_ctr_offset)]\n"
+#endif
+	"\t     args: <name>=fetcharg[:type]\n"
+	"\t fetcharg: (%<register>|$<efield>), @<address>, @<symbol>[+|-<offset>],\n"
+#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
+	"\t           $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
+#else
+	"\t           $stack<index>, $stack, $retval, $comm,\n"
+#endif
+	"\t           +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
+	"\t     type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"
+	"\t           b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
+	"\t           symstr, <type>\\[<array-size>\\]\n"
+#ifdef CONFIG_HIST_TRIGGERS
+	"\t    field: <stype> <name>;\n"
+	"\t    stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
+	"\t           [unsigned] char/int/long\n"
+#endif
+	"\t    efield: For event probes ('e' types), the field is on of the fields\n"
+	"\t            of the <attached-group>/<attached-event>.\n"
+#endif
+	"  events/\t\t- Directory containing all trace event subsystems:\n"
+	"      enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
+	"  events/<system>/\t- Directory containing all trace events for <system>:\n"
+	"      enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
+	"\t\t\t  events\n"
+	"      filter\t\t- If set, only events passing filter are traced\n"
+	"  events/<system>/<event>/\t- Directory containing control files for\n"
+	"\t\t\t  <event>:\n"
+	"      enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
+	"      filter\t\t- If set, only events passing filter are traced\n"
+	"      trigger\t\t- If set, a command to perform when event is hit\n"
+	"\t    Format: <trigger>[:count][if <filter>]\n"
+	"\t   trigger: traceon, traceoff\n"
+	"\t            enable_event:<system>:<event>\n"
+	"\t            disable_event:<system>:<event>\n"
+#ifdef CONFIG_HIST_TRIGGERS
+	"\t            enable_hist:<system>:<event>\n"
+	"\t            disable_hist:<system>:<event>\n"
+#endif
+#ifdef CONFIG_STACKTRACE
+	"\t\t    stacktrace\n"
+#endif
+#ifdef CONFIG_TRACER_SNAPSHOT
+	"\t\t    snapshot\n"
+#endif
+#ifdef CONFIG_HIST_TRIGGERS
+	"\t\t    hist (see below)\n"
+#endif
+	"\t   example: echo traceoff > events/block/block_unplug/trigger\n"
+	"\t            echo traceoff:3 > events/block/block_unplug/trigger\n"
+	"\t            echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
+	"\t                  events/block/block_unplug/trigger\n"
+	"\t   The first disables tracing every time block_unplug is hit.\n"
+	"\t   The second disables tracing the first 3 times block_unplug is hit.\n"
+	"\t   The third enables the kmalloc event the first 3 times block_unplug\n"
+	"\t     is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
+	"\t   Like function triggers, the counter is only decremented if it\n"
+	"\t    enabled or disabled tracing.\n"
+	"\t   To remove a trigger without a count:\n"
+	"\t     echo '!<trigger> > <system>/<event>/trigger\n"
+	"\t   To remove a trigger with a count:\n"
+	"\t     echo '!<trigger>:0 > <system>/<event>/trigger\n"
+	"\t   Filters can be ignored when removing a trigger.\n"
+#ifdef CONFIG_HIST_TRIGGERS
+	"      hist trigger\t- If set, event hits are aggregated into a hash table\n"
+	"\t    Format: hist:keys=<field1[,field2,...]>\n"
+	"\t            [:<var1>=<field|var_ref|numeric_literal>[,<var2>=...]]\n"
+	"\t            [:values=<field1[,field2,...]>]\n"
+	"\t            [:sort=<field1[,field2,...]>]\n"
+	"\t            [:size=#entries]\n"
+	"\t            [:pause][:continue][:clear]\n"
+	"\t            [:name=histname1]\n"
+	"\t            [:<handler>.<action>]\n"
+	"\t            [if <filter>]\n\n"
+	"\t    Note, special fields can be used as well:\n"
+	"\t            common_timestamp - to record current timestamp\n"
+	"\t            common_cpu - to record the CPU the event happened on\n"
+	"\n"
+	"\t    A hist trigger variable can be:\n"
+	"\t        - a reference to a field e.g. x=current_timestamp,\n"
+	"\t        - a reference to another variable e.g. y=$x,\n"
+	"\t        - a numeric literal: e.g. ms_per_sec=1000,\n"
+	"\t        - an arithmetic expression: e.g. time_secs=current_timestamp/1000\n"
+	"\n"
+	"\t    hist trigger arithmetic expressions support addition(+), subtraction(-),\n"
+	"\t    multiplication(*) and division(/) operators. An operand can be either a\n"
+	"\t    variable reference, field or numeric literal.\n"
+	"\n"
+	"\t    When a matching event is hit, an entry is added to a hash\n"
+	"\t    table using the key(s) and value(s) named, and the value of a\n"
+	"\t    sum called 'hitcount' is incremented.  Keys and values\n"
+	"\t    correspond to fields in the event's format description.  Keys\n"
+	"\t    can be any field, or the special string 'stacktrace'.\n"
+	"\t    Compound keys consisting of up to two fields can be specified\n"
+	"\t    by the 'keys' keyword.  Values must correspond to numeric\n"
+	"\t    fields.  Sort keys consisting of up to two fields can be\n"
+	"\t    specified using the 'sort' keyword.  The sort direction can\n"
+	"\t    be modified by appending '.descending' or '.ascending' to a\n"
+	"\t    sort field.  The 'size' parameter can be used to specify more\n"
+	"\t    or fewer than the default 2048 entries for the hashtable size.\n"
+	"\t    If a hist trigger is given a name using the 'name' parameter,\n"
+	"\t    its histogram data will be shared with other triggers of the\n"
+	"\t    same name, and trigger hits will update this common data.\n\n"
+	"\t    Reading the 'hist' file for the event will dump the hash\n"
+	"\t    table in its entirety to stdout.  If there are multiple hist\n"
+	"\t    triggers attached to an event, there will be a table for each\n"
+	"\t    trigger in the output.  The table displayed for a named\n"
+	"\t    trigger will be the same as any other instance having the\n"
+	"\t    same name.  The default format used to display a given field\n"
+	"\t    can be modified by appending any of the following modifiers\n"
+	"\t    to the field name, as applicable:\n\n"
+	"\t            .hex        display a number as a hex value\n"
+	"\t            .sym        display an address as a symbol\n"
+	"\t            .sym-offset display an address as a symbol and offset\n"
+	"\t            .execname   display a common_pid as a program name\n"
+	"\t            .syscall    display a syscall id as a syscall name\n"
+	"\t            .log2       display log2 value rather than raw number\n"
+	"\t            .buckets=size  display values in groups of size rather than raw number\n"
+	"\t            .usecs      display a common_timestamp in microseconds\n"
+	"\t            .percent    display a number of percentage value\n"
+	"\t            .graph      display a bar-graph of a value\n\n"
+	"\t    The 'pause' parameter can be used to pause an existing hist\n"
+	"\t    trigger or to start a hist trigger but not log any events\n"
+	"\t    until told to do so.  'continue' can be used to start or\n"
+	"\t    restart a paused hist trigger.\n\n"
+	"\t    The 'clear' parameter will clear the contents of a running\n"
+	"\t    hist trigger and leave its current paused/active state\n"
+	"\t    unchanged.\n\n"
+	"\t    The enable_hist and disable_hist triggers can be used to\n"
+	"\t    have one event conditionally start and stop another event's\n"
+	"\t    already-attached hist trigger.  The syntax is analogous to\n"
+	"\t    the enable_event and disable_event triggers.\n\n"
+	"\t    Hist trigger handlers and actions are executed whenever a\n"
+	"\t    a histogram entry is added or updated.  They take the form:\n\n"
+	"\t        <handler>.<action>\n\n"
+	"\t    The available handlers are:\n\n"
+	"\t        onmatch(matching.event)  - invoke on addition or update\n"
+	"\t        onmax(var)               - invoke if var exceeds current max\n"
+	"\t        onchange(var)            - invoke action if var changes\n\n"
+	"\t    The available actions are:\n\n"
+	"\t        trace(<synthetic_event>,param list)  - generate synthetic event\n"
+	"\t        save(field,...)                      - save current event fields\n"
+#ifdef CONFIG_TRACER_SNAPSHOT
+	"\t        snapshot()                           - snapshot the trace buffer\n\n"
+#endif
+#ifdef CONFIG_SYNTH_EVENTS
+	"  events/synthetic_events\t- Create/append/remove/show synthetic events\n"
+	"\t  Write into this file to define/undefine new synthetic events.\n"
+	"\t     example: echo 'myevent u64 lat; char name[]' >> synthetic_events\n"
+#endif
+#endif
+;
+
+static ssize_t
+tracing_readme_read(struct file *filp, char __user *ubuf,
+		       size_t cnt, loff_t *ppos)
+{
+	return simple_read_from_buffer(ubuf, cnt, ppos,
+					readme_msg, strlen(readme_msg));
+}
+
+static const struct file_operations tracing_readme_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_readme_read,
+	.llseek		= generic_file_llseek,
+};
+
+static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	int pid = ++(*pos);
+
+	return trace_find_tgid_ptr(pid);
+}
+
+static void *saved_tgids_start(struct seq_file *m, loff_t *pos)
+{
+	int pid = *pos;
+
+	return trace_find_tgid_ptr(pid);
+}
+
+static void saved_tgids_stop(struct seq_file *m, void *v)
+{
+}
+
+static int saved_tgids_show(struct seq_file *m, void *v)
+{
+	int *entry = (int *)v;
+	int pid = entry - tgid_map;
+	int tgid = *entry;
+
+	if (tgid == 0)
+		return SEQ_SKIP;
+
+	seq_printf(m, "%d %d\n", pid, tgid);
+	return 0;
+}
+
+static const struct seq_operations tracing_saved_tgids_seq_ops = {
+	.start		= saved_tgids_start,
+	.stop		= saved_tgids_stop,
+	.next		= saved_tgids_next,
+	.show		= saved_tgids_show,
+};
+
+static int tracing_saved_tgids_open(struct inode *inode, struct file *filp)
+{
+	int ret;
+
+	ret = tracing_check_open_get_tr(NULL);
+	if (ret)
+		return ret;
+
+	return seq_open(filp, &tracing_saved_tgids_seq_ops);
+}
+
+
+static const struct file_operations tracing_saved_tgids_fops = {
+	.open		= tracing_saved_tgids_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	unsigned int *ptr = v;
+
+	if (*pos || m->count)
+		ptr++;
+
+	(*pos)++;
+
+	for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
+	     ptr++) {
+		if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
+			continue;
+
+		return ptr;
+	}
+
+	return NULL;
+}
+
+static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
+{
+	void *v;
+	loff_t l = 0;
+
+	preempt_disable();
+	arch_spin_lock(&trace_cmdline_lock);
+
+	v = &savedcmd->map_cmdline_to_pid[0];
+	while (l <= *pos) {
+		v = saved_cmdlines_next(m, v, &l);
+		if (!v)
+			return NULL;
+	}
+
+	return v;
+}
+
+static void saved_cmdlines_stop(struct seq_file *m, void *v)
+{
+	arch_spin_unlock(&trace_cmdline_lock);
+	preempt_enable();
+}
+
+static int saved_cmdlines_show(struct seq_file *m, void *v)
+{
+	char buf[TASK_COMM_LEN];
+	unsigned int *pid = v;
+
+	__trace_find_cmdline(*pid, buf);
+	seq_printf(m, "%d %s\n", *pid, buf);
+	return 0;
+}
+
+static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
+	.start		= saved_cmdlines_start,
+	.next		= saved_cmdlines_next,
+	.stop		= saved_cmdlines_stop,
+	.show		= saved_cmdlines_show,
+};
+
+static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
+{
+	int ret;
+
+	ret = tracing_check_open_get_tr(NULL);
+	if (ret)
+		return ret;
+
+	return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
+}
+
+static const struct file_operations tracing_saved_cmdlines_fops = {
+	.open		= tracing_saved_cmdlines_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static ssize_t
+tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
+				 size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	int r;
+
+	preempt_disable();
+	arch_spin_lock(&trace_cmdline_lock);
+	r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
+	arch_spin_unlock(&trace_cmdline_lock);
+	preempt_enable();
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
+{
+	kfree(s->saved_cmdlines);
+	kfree(s->map_cmdline_to_pid);
+	kfree(s);
+}
+
+static int tracing_resize_saved_cmdlines(unsigned int val)
+{
+	struct saved_cmdlines_buffer *s, *savedcmd_temp;
+
+	s = kmalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	if (allocate_cmdlines_buffer(val, s) < 0) {
+		kfree(s);
+		return -ENOMEM;
+	}
+
+	preempt_disable();
+	arch_spin_lock(&trace_cmdline_lock);
+	savedcmd_temp = savedcmd;
+	savedcmd = s;
+	arch_spin_unlock(&trace_cmdline_lock);
+	preempt_enable();
+	free_saved_cmdlines_buffer(savedcmd_temp);
+
+	return 0;
+}
+
+static ssize_t
+tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
+				  size_t cnt, loff_t *ppos)
+{
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	/* must have at least 1 entry or less than PID_MAX_DEFAULT */
+	if (!val || val > PID_MAX_DEFAULT)
+		return -EINVAL;
+
+	ret = tracing_resize_saved_cmdlines((unsigned int)val);
+	if (ret < 0)
+		return ret;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static const struct file_operations tracing_saved_cmdlines_size_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_saved_cmdlines_size_read,
+	.write		= tracing_saved_cmdlines_size_write,
+};
+
+#ifdef CONFIG_TRACE_EVAL_MAP_FILE
+static union trace_eval_map_item *
+update_eval_map(union trace_eval_map_item *ptr)
+{
+	if (!ptr->map.eval_string) {
+		if (ptr->tail.next) {
+			ptr = ptr->tail.next;
+			/* Set ptr to the next real item (skip head) */
+			ptr++;
+		} else
+			return NULL;
+	}
+	return ptr;
+}
+
+static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	union trace_eval_map_item *ptr = v;
+
+	/*
+	 * Paranoid! If ptr points to end, we don't want to increment past it.
+	 * This really should never happen.
+	 */
+	(*pos)++;
+	ptr = update_eval_map(ptr);
+	if (WARN_ON_ONCE(!ptr))
+		return NULL;
+
+	ptr++;
+	ptr = update_eval_map(ptr);
+
+	return ptr;
+}
+
+static void *eval_map_start(struct seq_file *m, loff_t *pos)
+{
+	union trace_eval_map_item *v;
+	loff_t l = 0;
+
+	mutex_lock(&trace_eval_mutex);
+
+	v = trace_eval_maps;
+	if (v)
+		v++;
+
+	while (v && l < *pos) {
+		v = eval_map_next(m, v, &l);
+	}
+
+	return v;
+}
+
+static void eval_map_stop(struct seq_file *m, void *v)
+{
+	mutex_unlock(&trace_eval_mutex);
+}
+
+static int eval_map_show(struct seq_file *m, void *v)
+{
+	union trace_eval_map_item *ptr = v;
+
+	seq_printf(m, "%s %ld (%s)\n",
+		   ptr->map.eval_string, ptr->map.eval_value,
+		   ptr->map.system);
+
+	return 0;
+}
+
+static const struct seq_operations tracing_eval_map_seq_ops = {
+	.start		= eval_map_start,
+	.next		= eval_map_next,
+	.stop		= eval_map_stop,
+	.show		= eval_map_show,
+};
+
+static int tracing_eval_map_open(struct inode *inode, struct file *filp)
+{
+	int ret;
+
+	ret = tracing_check_open_get_tr(NULL);
+	if (ret)
+		return ret;
+
+	return seq_open(filp, &tracing_eval_map_seq_ops);
+}
+
+static const struct file_operations tracing_eval_map_fops = {
+	.open		= tracing_eval_map_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static inline union trace_eval_map_item *
+trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
+{
+	/* Return tail of array given the head */
+	return ptr + ptr->head.length + 1;
+}
+
+static void
+trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
+			   int len)
+{
+	struct trace_eval_map **stop;
+	struct trace_eval_map **map;
+	union trace_eval_map_item *map_array;
+	union trace_eval_map_item *ptr;
+
+	stop = start + len;
+
+	/*
+	 * The trace_eval_maps contains the map plus a head and tail item,
+	 * where the head holds the module and length of array, and the
+	 * tail holds a pointer to the next list.
+	 */
+	map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
+	if (!map_array) {
+		pr_warn("Unable to allocate trace eval mapping\n");
+		return;
+	}
+
+	mutex_lock(&trace_eval_mutex);
+
+	if (!trace_eval_maps)
+		trace_eval_maps = map_array;
+	else {
+		ptr = trace_eval_maps;
+		for (;;) {
+			ptr = trace_eval_jmp_to_tail(ptr);
+			if (!ptr->tail.next)
+				break;
+			ptr = ptr->tail.next;
+
+		}
+		ptr->tail.next = map_array;
+	}
+	map_array->head.mod = mod;
+	map_array->head.length = len;
+	map_array++;
+
+	for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
+		map_array->map = **map;
+		map_array++;
+	}
+	memset(map_array, 0, sizeof(*map_array));
+
+	mutex_unlock(&trace_eval_mutex);
+}
+
+static void trace_create_eval_file(struct dentry *d_tracer)
+{
+	trace_create_file("eval_map", TRACE_MODE_READ, d_tracer,
+			  NULL, &tracing_eval_map_fops);
+}
+
+#else /* CONFIG_TRACE_EVAL_MAP_FILE */
+static inline void trace_create_eval_file(struct dentry *d_tracer) { }
+static inline void trace_insert_eval_map_file(struct module *mod,
+			      struct trace_eval_map **start, int len) { }
+#endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
+
+static void trace_insert_eval_map(struct module *mod,
+				  struct trace_eval_map **start, int len)
+{
+	struct trace_eval_map **map;
+
+	if (len <= 0)
+		return;
+
+	map = start;
+
+	trace_event_eval_update(map, len);
+
+	trace_insert_eval_map_file(mod, start, len);
+}
+
+static ssize_t
+tracing_set_trace_read(struct file *filp, char __user *ubuf,
+		       size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	char buf[MAX_TRACER_SIZE+2];
+	int r;
+
+	mutex_lock(&trace_types_lock);
+	r = sprintf(buf, "%s\n", tr->current_trace->name);
+	mutex_unlock(&trace_types_lock);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+int tracer_init(struct tracer *t, struct trace_array *tr)
+{
+	tracing_reset_online_cpus(&tr->array_buffer);
+	return t->init(tr);
+}
+
+static void set_buffer_entries(struct array_buffer *buf, unsigned long val)
+{
+	int cpu;
+
+	for_each_tracing_cpu(cpu)
+		per_cpu_ptr(buf->data, cpu)->entries = val;
+}
+
+static void update_buffer_entries(struct array_buffer *buf, int cpu)
+{
+	if (cpu == RING_BUFFER_ALL_CPUS) {
+		set_buffer_entries(buf, ring_buffer_size(buf->buffer, 0));
+	} else {
+		per_cpu_ptr(buf->data, cpu)->entries = ring_buffer_size(buf->buffer, cpu);
+	}
+}
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+/* resize @tr's buffer to the size of @size_tr's entries */
+static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
+					struct array_buffer *size_buf, int cpu_id)
+{
+	int cpu, ret = 0;
+
+	if (cpu_id == RING_BUFFER_ALL_CPUS) {
+		for_each_tracing_cpu(cpu) {
+			ret = ring_buffer_resize(trace_buf->buffer,
+				 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
+			if (ret < 0)
+				break;
+			per_cpu_ptr(trace_buf->data, cpu)->entries =
+				per_cpu_ptr(size_buf->data, cpu)->entries;
+		}
+	} else {
+		ret = ring_buffer_resize(trace_buf->buffer,
+				 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
+		if (ret == 0)
+			per_cpu_ptr(trace_buf->data, cpu_id)->entries =
+				per_cpu_ptr(size_buf->data, cpu_id)->entries;
+	}
+
+	return ret;
+}
+#endif /* CONFIG_TRACER_MAX_TRACE */
+
+static int __tracing_resize_ring_buffer(struct trace_array *tr,
+					unsigned long size, int cpu)
+{
+	int ret;
+
+	/*
+	 * If kernel or user changes the size of the ring buffer
+	 * we use the size that was given, and we can forget about
+	 * expanding it later.
+	 */
+	ring_buffer_expanded = true;
+
+	/* May be called before buffers are initialized */
+	if (!tr->array_buffer.buffer)
+		return 0;
+
+	/* Do not allow tracing while resizing ring buffer */
+	tracing_stop_tr(tr);
+
+	ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu);
+	if (ret < 0)
+		goto out_start;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (!tr->allocated_snapshot)
+		goto out;
+
+	ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
+	if (ret < 0) {
+		int r = resize_buffer_duplicate_size(&tr->array_buffer,
+						     &tr->array_buffer, cpu);
+		if (r < 0) {
+			/*
+			 * AARGH! We are left with different
+			 * size max buffer!!!!
+			 * The max buffer is our "snapshot" buffer.
+			 * When a tracer needs a snapshot (one of the
+			 * latency tracers), it swaps the max buffer
+			 * with the saved snap shot. We succeeded to
+			 * update the size of the main buffer, but failed to
+			 * update the size of the max buffer. But when we tried
+			 * to reset the main buffer to the original size, we
+			 * failed there too. This is very unlikely to
+			 * happen, but if it does, warn and kill all
+			 * tracing.
+			 */
+			WARN_ON(1);
+			tracing_disabled = 1;
+		}
+		goto out_start;
+	}
+
+	update_buffer_entries(&tr->max_buffer, cpu);
+
+ out:
+#endif /* CONFIG_TRACER_MAX_TRACE */
+
+	update_buffer_entries(&tr->array_buffer, cpu);
+ out_start:
+	tracing_start_tr(tr);
+	return ret;
+}
+
+ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
+				  unsigned long size, int cpu_id)
+{
+	int ret;
+
+	mutex_lock(&trace_types_lock);
+
+	if (cpu_id != RING_BUFFER_ALL_CPUS) {
+		/* make sure, this cpu is enabled in the mask */
+		if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
+	ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
+	if (ret < 0)
+		ret = -ENOMEM;
+
+out:
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+
+/**
+ * tracing_update_buffers - used by tracing facility to expand ring buffers
+ *
+ * To save on memory when the tracing is never used on a system with it
+ * configured in. The ring buffers are set to a minimum size. But once
+ * a user starts to use the tracing facility, then they need to grow
+ * to their default size.
+ *
+ * This function is to be called when a tracer is about to be used.
+ */
+int tracing_update_buffers(void)
+{
+	int ret = 0;
+
+	mutex_lock(&trace_types_lock);
+	if (!ring_buffer_expanded)
+		ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
+						RING_BUFFER_ALL_CPUS);
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+struct trace_option_dentry;
+
+static void
+create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
+
+/*
+ * Used to clear out the tracer before deletion of an instance.
+ * Must have trace_types_lock held.
+ */
+static void tracing_set_nop(struct trace_array *tr)
+{
+	if (tr->current_trace == &nop_trace)
+		return;
+	
+	tr->current_trace->enabled--;
+
+	if (tr->current_trace->reset)
+		tr->current_trace->reset(tr);
+
+	tr->current_trace = &nop_trace;
+}
+
+static bool tracer_options_updated;
+
+static void add_tracer_options(struct trace_array *tr, struct tracer *t)
+{
+	/* Only enable if the directory has been created already. */
+	if (!tr->dir)
+		return;
+
+	/* Only create trace option files after update_tracer_options finish */
+	if (!tracer_options_updated)
+		return;
+
+	create_trace_option_files(tr, t);
+}
+
+int tracing_set_tracer(struct trace_array *tr, const char *buf)
+{
+	struct tracer *t;
+#ifdef CONFIG_TRACER_MAX_TRACE
+	bool had_max_tr;
+#endif
+	int ret = 0;
+
+	mutex_lock(&trace_types_lock);
+
+	if (!ring_buffer_expanded) {
+		ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
+						RING_BUFFER_ALL_CPUS);
+		if (ret < 0)
+			goto out;
+		ret = 0;
+	}
+
+	for (t = trace_types; t; t = t->next) {
+		if (strcmp(t->name, buf) == 0)
+			break;
+	}
+	if (!t) {
+		ret = -EINVAL;
+		goto out;
+	}
+	if (t == tr->current_trace)
+		goto out;
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+	if (t->use_max_tr) {
+		local_irq_disable();
+		arch_spin_lock(&tr->max_lock);
+		if (tr->cond_snapshot)
+			ret = -EBUSY;
+		arch_spin_unlock(&tr->max_lock);
+		local_irq_enable();
+		if (ret)
+			goto out;
+	}
+#endif
+	/* Some tracers won't work on kernel command line */
+	if (system_state < SYSTEM_RUNNING && t->noboot) {
+		pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
+			t->name);
+		goto out;
+	}
+
+	/* Some tracers are only allowed for the top level buffer */
+	if (!trace_ok_for_array(t, tr)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* If trace pipe files are being read, we can't change the tracer */
+	if (tr->trace_ref) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	trace_branch_disable();
+
+	tr->current_trace->enabled--;
+
+	if (tr->current_trace->reset)
+		tr->current_trace->reset(tr);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	had_max_tr = tr->current_trace->use_max_tr;
+
+	/* Current trace needs to be nop_trace before synchronize_rcu */
+	tr->current_trace = &nop_trace;
+
+	if (had_max_tr && !t->use_max_tr) {
+		/*
+		 * We need to make sure that the update_max_tr sees that
+		 * current_trace changed to nop_trace to keep it from
+		 * swapping the buffers after we resize it.
+		 * The update_max_tr is called from interrupts disabled
+		 * so a synchronized_sched() is sufficient.
+		 */
+		synchronize_rcu();
+		free_snapshot(tr);
+	}
+
+	if (t->use_max_tr && !tr->allocated_snapshot) {
+		ret = tracing_alloc_snapshot_instance(tr);
+		if (ret < 0)
+			goto out;
+	}
+#else
+	tr->current_trace = &nop_trace;
+#endif
+
+	if (t->init) {
+		ret = tracer_init(t, tr);
+		if (ret)
+			goto out;
+	}
+
+	tr->current_trace = t;
+	tr->current_trace->enabled++;
+	trace_branch_enable(tr);
+ out:
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+static ssize_t
+tracing_set_trace_write(struct file *filp, const char __user *ubuf,
+			size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	char buf[MAX_TRACER_SIZE+1];
+	char *name;
+	size_t ret;
+	int err;
+
+	ret = cnt;
+
+	if (cnt > MAX_TRACER_SIZE)
+		cnt = MAX_TRACER_SIZE;
+
+	if (copy_from_user(buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	name = strim(buf);
+
+	err = tracing_set_tracer(tr, name);
+	if (err)
+		return err;
+
+	*ppos += ret;
+
+	return ret;
+}
+
+static ssize_t
+tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
+		   size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	int r;
+
+	r = snprintf(buf, sizeof(buf), "%ld\n",
+		     *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
+	if (r > sizeof(buf))
+		r = sizeof(buf);
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
+		    size_t cnt, loff_t *ppos)
+{
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	*ptr = val * 1000;
+
+	return cnt;
+}
+
+static ssize_t
+tracing_thresh_read(struct file *filp, char __user *ubuf,
+		    size_t cnt, loff_t *ppos)
+{
+	return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
+}
+
+static ssize_t
+tracing_thresh_write(struct file *filp, const char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	int ret;
+
+	mutex_lock(&trace_types_lock);
+	ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
+	if (ret < 0)
+		goto out;
+
+	if (tr->current_trace->update_thresh) {
+		ret = tr->current_trace->update_thresh(tr);
+		if (ret < 0)
+			goto out;
+	}
+
+	ret = cnt;
+out:
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+
+static ssize_t
+tracing_max_lat_read(struct file *filp, char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+
+	return tracing_nsecs_read(&tr->max_latency, ubuf, cnt, ppos);
+}
+
+static ssize_t
+tracing_max_lat_write(struct file *filp, const char __user *ubuf,
+		      size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+
+	return tracing_nsecs_write(&tr->max_latency, ubuf, cnt, ppos);
+}
+
+#endif
+
+static int open_pipe_on_cpu(struct trace_array *tr, int cpu)
+{
+	if (cpu == RING_BUFFER_ALL_CPUS) {
+		if (cpumask_empty(tr->pipe_cpumask)) {
+			cpumask_setall(tr->pipe_cpumask);
+			return 0;
+		}
+	} else if (!cpumask_test_cpu(cpu, tr->pipe_cpumask)) {
+		cpumask_set_cpu(cpu, tr->pipe_cpumask);
+		return 0;
+	}
+	return -EBUSY;
+}
+
+static void close_pipe_on_cpu(struct trace_array *tr, int cpu)
+{
+	if (cpu == RING_BUFFER_ALL_CPUS) {
+		WARN_ON(!cpumask_full(tr->pipe_cpumask));
+		cpumask_clear(tr->pipe_cpumask);
+	} else {
+		WARN_ON(!cpumask_test_cpu(cpu, tr->pipe_cpumask));
+		cpumask_clear_cpu(cpu, tr->pipe_cpumask);
+	}
+}
+
+static int tracing_open_pipe(struct inode *inode, struct file *filp)
+{
+	struct trace_array *tr = inode->i_private;
+	struct trace_iterator *iter;
+	int cpu;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	mutex_lock(&trace_types_lock);
+	cpu = tracing_get_cpu(inode);
+	ret = open_pipe_on_cpu(tr, cpu);
+	if (ret)
+		goto fail_pipe_on_cpu;
+
+	/* create a buffer to store the information to pass to userspace */
+	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+	if (!iter) {
+		ret = -ENOMEM;
+		goto fail_alloc_iter;
+	}
+
+	trace_seq_init(&iter->seq);
+	iter->trace = tr->current_trace;
+
+	if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	/* trace pipe does not show start of buffer */
+	cpumask_setall(iter->started);
+
+	if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
+		iter->iter_flags |= TRACE_FILE_LAT_FMT;
+
+	/* Output in nanoseconds only if we are using a clock in nanoseconds. */
+	if (trace_clocks[tr->clock_id].in_ns)
+		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
+
+	iter->tr = tr;
+	iter->array_buffer = &tr->array_buffer;
+	iter->cpu_file = cpu;
+	mutex_init(&iter->mutex);
+	filp->private_data = iter;
+
+	if (iter->trace->pipe_open)
+		iter->trace->pipe_open(iter);
+
+	nonseekable_open(inode, filp);
+
+	tr->trace_ref++;
+
+	mutex_unlock(&trace_types_lock);
+	return ret;
+
+fail:
+	kfree(iter);
+fail_alloc_iter:
+	close_pipe_on_cpu(tr, cpu);
+fail_pipe_on_cpu:
+	__trace_array_put(tr);
+	mutex_unlock(&trace_types_lock);
+	return ret;
+}
+
+static int tracing_release_pipe(struct inode *inode, struct file *file)
+{
+	struct trace_iterator *iter = file->private_data;
+	struct trace_array *tr = inode->i_private;
+
+	mutex_lock(&trace_types_lock);
+
+	tr->trace_ref--;
+
+	if (iter->trace->pipe_close)
+		iter->trace->pipe_close(iter);
+	close_pipe_on_cpu(tr, iter->cpu_file);
+	mutex_unlock(&trace_types_lock);
+
+	free_cpumask_var(iter->started);
+	kfree(iter->fmt);
+	kfree(iter->temp);
+	mutex_destroy(&iter->mutex);
+	kfree(iter);
+
+	trace_array_put(tr);
+
+	return 0;
+}
+
+static __poll_t
+trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
+{
+	struct trace_array *tr = iter->tr;
+
+	/* Iterators are static, they should be filled or empty */
+	if (trace_buffer_iter(iter, iter->cpu_file))
+		return EPOLLIN | EPOLLRDNORM;
+
+	if (tr->trace_flags & TRACE_ITER_BLOCK)
+		/*
+		 * Always select as readable when in blocking mode
+		 */
+		return EPOLLIN | EPOLLRDNORM;
+	else
+		return ring_buffer_poll_wait(iter->array_buffer->buffer, iter->cpu_file,
+					     filp, poll_table, iter->tr->buffer_percent);
+}
+
+static __poll_t
+tracing_poll_pipe(struct file *filp, poll_table *poll_table)
+{
+	struct trace_iterator *iter = filp->private_data;
+
+	return trace_poll(iter, filp, poll_table);
+}
+
+/* Must be called with iter->mutex held. */
+static int tracing_wait_pipe(struct file *filp)
+{
+	struct trace_iterator *iter = filp->private_data;
+	int ret;
+
+	while (trace_empty(iter)) {
+
+		if ((filp->f_flags & O_NONBLOCK)) {
+			return -EAGAIN;
+		}
+
+		/*
+		 * We block until we read something and tracing is disabled.
+		 * We still block if tracing is disabled, but we have never
+		 * read anything. This allows a user to cat this file, and
+		 * then enable tracing. But after we have read something,
+		 * we give an EOF when tracing is again disabled.
+		 *
+		 * iter->pos will be 0 if we haven't read anything.
+		 */
+		if (!tracer_tracing_is_on(iter->tr) && iter->pos)
+			break;
+
+		mutex_unlock(&iter->mutex);
+
+		ret = wait_on_pipe(iter, 0);
+
+		mutex_lock(&iter->mutex);
+
+		if (ret)
+			return ret;
+	}
+
+	return 1;
+}
+
+/*
+ * Consumer reader.
+ */
+static ssize_t
+tracing_read_pipe(struct file *filp, char __user *ubuf,
+		  size_t cnt, loff_t *ppos)
+{
+	struct trace_iterator *iter = filp->private_data;
+	ssize_t sret;
+
+	/*
+	 * Avoid more than one consumer on a single file descriptor
+	 * This is just a matter of traces coherency, the ring buffer itself
+	 * is protected.
+	 */
+	mutex_lock(&iter->mutex);
+
+	/* return any leftover data */
+	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
+	if (sret != -EBUSY)
+		goto out;
+
+	trace_seq_init(&iter->seq);
+
+	if (iter->trace->read) {
+		sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
+		if (sret)
+			goto out;
+	}
+
+waitagain:
+	sret = tracing_wait_pipe(filp);
+	if (sret <= 0)
+		goto out;
+
+	/* stop when tracing is finished */
+	if (trace_empty(iter)) {
+		sret = 0;
+		goto out;
+	}
+
+	if (cnt >= PAGE_SIZE)
+		cnt = PAGE_SIZE - 1;
+
+	/* reset all but tr, trace, and overruns */
+	trace_iterator_reset(iter);
+	cpumask_clear(iter->started);
+	trace_seq_init(&iter->seq);
+
+	trace_event_read_lock();
+	trace_access_lock(iter->cpu_file);
+	while (trace_find_next_entry_inc(iter) != NULL) {
+		enum print_line_t ret;
+		int save_len = iter->seq.seq.len;
+
+		ret = print_trace_line(iter);
+		if (ret == TRACE_TYPE_PARTIAL_LINE) {
+			/*
+			 * If one print_trace_line() fills entire trace_seq in one shot,
+			 * trace_seq_to_user() will returns -EBUSY because save_len == 0,
+			 * In this case, we need to consume it, otherwise, loop will peek
+			 * this event next time, resulting in an infinite loop.
+			 */
+			if (save_len == 0) {
+				iter->seq.full = 0;
+				trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
+				trace_consume(iter);
+				break;
+			}
+
+			/* In other cases, don't print partial lines */
+			iter->seq.seq.len = save_len;
+			break;
+		}
+		if (ret != TRACE_TYPE_NO_CONSUME)
+			trace_consume(iter);
+
+		if (trace_seq_used(&iter->seq) >= cnt)
+			break;
+
+		/*
+		 * Setting the full flag means we reached the trace_seq buffer
+		 * size and we should leave by partial output condition above.
+		 * One of the trace_seq_* functions is not used properly.
+		 */
+		WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
+			  iter->ent->type);
+	}
+	trace_access_unlock(iter->cpu_file);
+	trace_event_read_unlock();
+
+	/* Now copy what we have to the user */
+	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
+	if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
+		trace_seq_init(&iter->seq);
+
+	/*
+	 * If there was nothing to send to user, in spite of consuming trace
+	 * entries, go back to wait for more entries.
+	 */
+	if (sret == -EBUSY)
+		goto waitagain;
+
+out:
+	mutex_unlock(&iter->mutex);
+
+	return sret;
+}
+
+static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
+				     unsigned int idx)
+{
+	__free_page(spd->pages[idx]);
+}
+
+static size_t
+tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
+{
+	size_t count;
+	int save_len;
+	int ret;
+
+	/* Seq buffer is page-sized, exactly what we need. */
+	for (;;) {
+		save_len = iter->seq.seq.len;
+		ret = print_trace_line(iter);
+
+		if (trace_seq_has_overflowed(&iter->seq)) {
+			iter->seq.seq.len = save_len;
+			break;
+		}
+
+		/*
+		 * This should not be hit, because it should only
+		 * be set if the iter->seq overflowed. But check it
+		 * anyway to be safe.
+		 */
+		if (ret == TRACE_TYPE_PARTIAL_LINE) {
+			iter->seq.seq.len = save_len;
+			break;
+		}
+
+		count = trace_seq_used(&iter->seq) - save_len;
+		if (rem < count) {
+			rem = 0;
+			iter->seq.seq.len = save_len;
+			break;
+		}
+
+		if (ret != TRACE_TYPE_NO_CONSUME)
+			trace_consume(iter);
+		rem -= count;
+		if (!trace_find_next_entry_inc(iter))	{
+			rem = 0;
+			iter->ent = NULL;
+			break;
+		}
+	}
+
+	return rem;
+}
+
+static ssize_t tracing_splice_read_pipe(struct file *filp,
+					loff_t *ppos,
+					struct pipe_inode_info *pipe,
+					size_t len,
+					unsigned int flags)
+{
+	struct page *pages_def[PIPE_DEF_BUFFERS];
+	struct partial_page partial_def[PIPE_DEF_BUFFERS];
+	struct trace_iterator *iter = filp->private_data;
+	struct splice_pipe_desc spd = {
+		.pages		= pages_def,
+		.partial	= partial_def,
+		.nr_pages	= 0, /* This gets updated below. */
+		.nr_pages_max	= PIPE_DEF_BUFFERS,
+		.ops		= &default_pipe_buf_ops,
+		.spd_release	= tracing_spd_release_pipe,
+	};
+	ssize_t ret;
+	size_t rem;
+	unsigned int i;
+
+	if (splice_grow_spd(pipe, &spd))
+		return -ENOMEM;
+
+	mutex_lock(&iter->mutex);
+
+	if (iter->trace->splice_read) {
+		ret = iter->trace->splice_read(iter, filp,
+					       ppos, pipe, len, flags);
+		if (ret)
+			goto out_err;
+	}
+
+	ret = tracing_wait_pipe(filp);
+	if (ret <= 0)
+		goto out_err;
+
+	if (!iter->ent && !trace_find_next_entry_inc(iter)) {
+		ret = -EFAULT;
+		goto out_err;
+	}
+
+	trace_event_read_lock();
+	trace_access_lock(iter->cpu_file);
+
+	/* Fill as many pages as possible. */
+	for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
+		spd.pages[i] = alloc_page(GFP_KERNEL);
+		if (!spd.pages[i])
+			break;
+
+		rem = tracing_fill_pipe_page(rem, iter);
+
+		/* Copy the data into the page, so we can start over. */
+		ret = trace_seq_to_buffer(&iter->seq,
+					  page_address(spd.pages[i]),
+					  trace_seq_used(&iter->seq));
+		if (ret < 0) {
+			__free_page(spd.pages[i]);
+			break;
+		}
+		spd.partial[i].offset = 0;
+		spd.partial[i].len = trace_seq_used(&iter->seq);
+
+		trace_seq_init(&iter->seq);
+	}
+
+	trace_access_unlock(iter->cpu_file);
+	trace_event_read_unlock();
+	mutex_unlock(&iter->mutex);
+
+	spd.nr_pages = i;
+
+	if (i)
+		ret = splice_to_pipe(pipe, &spd);
+	else
+		ret = 0;
+out:
+	splice_shrink_spd(&spd);
+	return ret;
+
+out_err:
+	mutex_unlock(&iter->mutex);
+	goto out;
+}
+
+static ssize_t
+tracing_entries_read(struct file *filp, char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	struct inode *inode = file_inode(filp);
+	struct trace_array *tr = inode->i_private;
+	int cpu = tracing_get_cpu(inode);
+	char buf[64];
+	int r = 0;
+	ssize_t ret;
+
+	mutex_lock(&trace_types_lock);
+
+	if (cpu == RING_BUFFER_ALL_CPUS) {
+		int cpu, buf_size_same;
+		unsigned long size;
+
+		size = 0;
+		buf_size_same = 1;
+		/* check if all cpu sizes are same */
+		for_each_tracing_cpu(cpu) {
+			/* fill in the size from first enabled cpu */
+			if (size == 0)
+				size = per_cpu_ptr(tr->array_buffer.data, cpu)->entries;
+			if (size != per_cpu_ptr(tr->array_buffer.data, cpu)->entries) {
+				buf_size_same = 0;
+				break;
+			}
+		}
+
+		if (buf_size_same) {
+			if (!ring_buffer_expanded)
+				r = sprintf(buf, "%lu (expanded: %lu)\n",
+					    size >> 10,
+					    trace_buf_size >> 10);
+			else
+				r = sprintf(buf, "%lu\n", size >> 10);
+		} else
+			r = sprintf(buf, "X\n");
+	} else
+		r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10);
+
+	mutex_unlock(&trace_types_lock);
+
+	ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+	return ret;
+}
+
+static ssize_t
+tracing_entries_write(struct file *filp, const char __user *ubuf,
+		      size_t cnt, loff_t *ppos)
+{
+	struct inode *inode = file_inode(filp);
+	struct trace_array *tr = inode->i_private;
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	/* must have at least 1 entry */
+	if (!val)
+		return -EINVAL;
+
+	/* value is in KB */
+	val <<= 10;
+	ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
+	if (ret < 0)
+		return ret;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static ssize_t
+tracing_total_entries_read(struct file *filp, char __user *ubuf,
+				size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	char buf[64];
+	int r, cpu;
+	unsigned long size = 0, expanded_size = 0;
+
+	mutex_lock(&trace_types_lock);
+	for_each_tracing_cpu(cpu) {
+		size += per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10;
+		if (!ring_buffer_expanded)
+			expanded_size += trace_buf_size >> 10;
+	}
+	if (ring_buffer_expanded)
+		r = sprintf(buf, "%lu\n", size);
+	else
+		r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
+	mutex_unlock(&trace_types_lock);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
+			  size_t cnt, loff_t *ppos)
+{
+	/*
+	 * There is no need to read what the user has written, this function
+	 * is just to make sure that there is no error when "echo" is used
+	 */
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static int
+tracing_free_buffer_release(struct inode *inode, struct file *filp)
+{
+	struct trace_array *tr = inode->i_private;
+
+	/* disable tracing ? */
+	if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
+		tracer_tracing_off(tr);
+	/* resize the ring buffer to 0 */
+	tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
+
+	trace_array_put(tr);
+
+	return 0;
+}
+
+static ssize_t
+tracing_mark_write(struct file *filp, const char __user *ubuf,
+					size_t cnt, loff_t *fpos)
+{
+	struct trace_array *tr = filp->private_data;
+	struct ring_buffer_event *event;
+	enum event_trigger_type tt = ETT_NONE;
+	struct trace_buffer *buffer;
+	struct print_entry *entry;
+	ssize_t written;
+	int size;
+	int len;
+
+/* Used in tracing_mark_raw_write() as well */
+#define FAULTED_STR "<faulted>"
+#define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */
+
+	if (tracing_disabled)
+		return -EINVAL;
+
+	if (!(tr->trace_flags & TRACE_ITER_MARKERS))
+		return -EINVAL;
+
+	if (cnt > TRACE_BUF_SIZE)
+		cnt = TRACE_BUF_SIZE;
+
+	BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
+
+	size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */
+
+	/* If less than "<faulted>", then make sure we can still add that */
+	if (cnt < FAULTED_SIZE)
+		size += FAULTED_SIZE - cnt;
+
+	buffer = tr->array_buffer.buffer;
+	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
+					    tracing_gen_ctx());
+	if (unlikely(!event))
+		/* Ring buffer disabled, return as if not open for write */
+		return -EBADF;
+
+	entry = ring_buffer_event_data(event);
+	entry->ip = _THIS_IP_;
+
+	len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
+	if (len) {
+		memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
+		cnt = FAULTED_SIZE;
+		written = -EFAULT;
+	} else
+		written = cnt;
+
+	if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
+		/* do not add \n before testing triggers, but add \0 */
+		entry->buf[cnt] = '\0';
+		tt = event_triggers_call(tr->trace_marker_file, buffer, entry, event);
+	}
+
+	if (entry->buf[cnt - 1] != '\n') {
+		entry->buf[cnt] = '\n';
+		entry->buf[cnt + 1] = '\0';
+	} else
+		entry->buf[cnt] = '\0';
+
+	if (static_branch_unlikely(&trace_marker_exports_enabled))
+		ftrace_exports(event, TRACE_EXPORT_MARKER);
+	__buffer_unlock_commit(buffer, event);
+
+	if (tt)
+		event_triggers_post_call(tr->trace_marker_file, tt);
+
+	return written;
+}
+
+/* Limit it for now to 3K (including tag) */
+#define RAW_DATA_MAX_SIZE (1024*3)
+
+static ssize_t
+tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
+					size_t cnt, loff_t *fpos)
+{
+	struct trace_array *tr = filp->private_data;
+	struct ring_buffer_event *event;
+	struct trace_buffer *buffer;
+	struct raw_data_entry *entry;
+	ssize_t written;
+	int size;
+	int len;
+
+#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
+
+	if (tracing_disabled)
+		return -EINVAL;
+
+	if (!(tr->trace_flags & TRACE_ITER_MARKERS))
+		return -EINVAL;
+
+	/* The marker must at least have a tag id */
+	if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE)
+		return -EINVAL;
+
+	if (cnt > TRACE_BUF_SIZE)
+		cnt = TRACE_BUF_SIZE;
+
+	BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
+
+	size = sizeof(*entry) + cnt;
+	if (cnt < FAULT_SIZE_ID)
+		size += FAULT_SIZE_ID - cnt;
+
+	buffer = tr->array_buffer.buffer;
+	event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
+					    tracing_gen_ctx());
+	if (!event)
+		/* Ring buffer disabled, return as if not open for write */
+		return -EBADF;
+
+	entry = ring_buffer_event_data(event);
+
+	len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
+	if (len) {
+		entry->id = -1;
+		memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
+		written = -EFAULT;
+	} else
+		written = cnt;
+
+	__buffer_unlock_commit(buffer, event);
+
+	return written;
+}
+
+static int tracing_clock_show(struct seq_file *m, void *v)
+{
+	struct trace_array *tr = m->private;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
+		seq_printf(m,
+			"%s%s%s%s", i ? " " : "",
+			i == tr->clock_id ? "[" : "", trace_clocks[i].name,
+			i == tr->clock_id ? "]" : "");
+	seq_putc(m, '\n');
+
+	return 0;
+}
+
+int tracing_set_clock(struct trace_array *tr, const char *clockstr)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
+		if (strcmp(trace_clocks[i].name, clockstr) == 0)
+			break;
+	}
+	if (i == ARRAY_SIZE(trace_clocks))
+		return -EINVAL;
+
+	mutex_lock(&trace_types_lock);
+
+	tr->clock_id = i;
+
+	ring_buffer_set_clock(tr->array_buffer.buffer, trace_clocks[i].func);
+
+	/*
+	 * New clock may not be consistent with the previous clock.
+	 * Reset the buffer so that it doesn't have incomparable timestamps.
+	 */
+	tracing_reset_online_cpus(&tr->array_buffer);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (tr->max_buffer.buffer)
+		ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
+	tracing_reset_online_cpus(&tr->max_buffer);
+#endif
+
+	mutex_unlock(&trace_types_lock);
+
+	return 0;
+}
+
+static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
+				   size_t cnt, loff_t *fpos)
+{
+	struct seq_file *m = filp->private_data;
+	struct trace_array *tr = m->private;
+	char buf[64];
+	const char *clockstr;
+	int ret;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	clockstr = strstrip(buf);
+
+	ret = tracing_set_clock(tr, clockstr);
+	if (ret)
+		return ret;
+
+	*fpos += cnt;
+
+	return cnt;
+}
+
+static int tracing_clock_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	ret = single_open(file, tracing_clock_show, inode->i_private);
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
+}
+
+static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
+{
+	struct trace_array *tr = m->private;
+
+	mutex_lock(&trace_types_lock);
+
+	if (ring_buffer_time_stamp_abs(tr->array_buffer.buffer))
+		seq_puts(m, "delta [absolute]\n");
+	else
+		seq_puts(m, "[delta] absolute\n");
+
+	mutex_unlock(&trace_types_lock);
+
+	return 0;
+}
+
+static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
+}
+
+u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe)
+{
+	if (rbe == this_cpu_read(trace_buffered_event))
+		return ring_buffer_time_stamp(buffer);
+
+	return ring_buffer_event_time_stamp(buffer, rbe);
+}
+
+/*
+ * Set or disable using the per CPU trace_buffer_event when possible.
+ */
+int tracing_set_filter_buffering(struct trace_array *tr, bool set)
+{
+	int ret = 0;
+
+	mutex_lock(&trace_types_lock);
+
+	if (set && tr->no_filter_buffering_ref++)
+		goto out;
+
+	if (!set) {
+		if (WARN_ON_ONCE(!tr->no_filter_buffering_ref)) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		--tr->no_filter_buffering_ref;
+	}
+ out:
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+struct ftrace_buffer_info {
+	struct trace_iterator	iter;
+	void			*spare;
+	unsigned int		spare_cpu;
+	unsigned int		read;
+};
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+static int tracing_snapshot_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	struct trace_iterator *iter;
+	struct seq_file *m;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	if (file->f_mode & FMODE_READ) {
+		iter = __tracing_open(inode, file, true);
+		if (IS_ERR(iter))
+			ret = PTR_ERR(iter);
+	} else {
+		/* Writes still need the seq_file to hold the private data */
+		ret = -ENOMEM;
+		m = kzalloc(sizeof(*m), GFP_KERNEL);
+		if (!m)
+			goto out;
+		iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+		if (!iter) {
+			kfree(m);
+			goto out;
+		}
+		ret = 0;
+
+		iter->tr = tr;
+		iter->array_buffer = &tr->max_buffer;
+		iter->cpu_file = tracing_get_cpu(inode);
+		m->private = iter;
+		file->private_data = m;
+	}
+out:
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
+}
+
+static void tracing_swap_cpu_buffer(void *tr)
+{
+	update_max_tr_single((struct trace_array *)tr, current, smp_processor_id());
+}
+
+static ssize_t
+tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
+		       loff_t *ppos)
+{
+	struct seq_file *m = filp->private_data;
+	struct trace_iterator *iter = m->private;
+	struct trace_array *tr = iter->tr;
+	unsigned long val;
+	int ret;
+
+	ret = tracing_update_buffers();
+	if (ret < 0)
+		return ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	mutex_lock(&trace_types_lock);
+
+	if (tr->current_trace->use_max_tr) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	local_irq_disable();
+	arch_spin_lock(&tr->max_lock);
+	if (tr->cond_snapshot)
+		ret = -EBUSY;
+	arch_spin_unlock(&tr->max_lock);
+	local_irq_enable();
+	if (ret)
+		goto out;
+
+	switch (val) {
+	case 0:
+		if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
+			ret = -EINVAL;
+			break;
+		}
+		if (tr->allocated_snapshot)
+			free_snapshot(tr);
+		break;
+	case 1:
+/* Only allow per-cpu swap if the ring buffer supports it */
+#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
+		if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
+			ret = -EINVAL;
+			break;
+		}
+#endif
+		if (tr->allocated_snapshot)
+			ret = resize_buffer_duplicate_size(&tr->max_buffer,
+					&tr->array_buffer, iter->cpu_file);
+		else
+			ret = tracing_alloc_snapshot_instance(tr);
+		if (ret < 0)
+			break;
+		/* Now, we're going to swap */
+		if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
+			local_irq_disable();
+			update_max_tr(tr, current, smp_processor_id(), NULL);
+			local_irq_enable();
+		} else {
+			smp_call_function_single(iter->cpu_file, tracing_swap_cpu_buffer,
+						 (void *)tr, 1);
+		}
+		break;
+	default:
+		if (tr->allocated_snapshot) {
+			if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
+				tracing_reset_online_cpus(&tr->max_buffer);
+			else
+				tracing_reset_cpu(&tr->max_buffer, iter->cpu_file);
+		}
+		break;
+	}
+
+	if (ret >= 0) {
+		*ppos += cnt;
+		ret = cnt;
+	}
+out:
+	mutex_unlock(&trace_types_lock);
+	return ret;
+}
+
+static int tracing_snapshot_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *m = file->private_data;
+	int ret;
+
+	ret = tracing_release(inode, file);
+
+	if (file->f_mode & FMODE_READ)
+		return ret;
+
+	/* If write only, the seq_file is just a stub */
+	if (m)
+		kfree(m->private);
+	kfree(m);
+
+	return 0;
+}
+
+static int tracing_buffers_open(struct inode *inode, struct file *filp);
+static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
+				    size_t count, loff_t *ppos);
+static int tracing_buffers_release(struct inode *inode, struct file *file);
+static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
+		   struct pipe_inode_info *pipe, size_t len, unsigned int flags);
+
+static int snapshot_raw_open(struct inode *inode, struct file *filp)
+{
+	struct ftrace_buffer_info *info;
+	int ret;
+
+	/* The following checks for tracefs lockdown */
+	ret = tracing_buffers_open(inode, filp);
+	if (ret < 0)
+		return ret;
+
+	info = filp->private_data;
+
+	if (info->iter.trace->use_max_tr) {
+		tracing_buffers_release(inode, filp);
+		return -EBUSY;
+	}
+
+	info->iter.snapshot = true;
+	info->iter.array_buffer = &info->iter.tr->max_buffer;
+
+	return ret;
+}
+
+#endif /* CONFIG_TRACER_SNAPSHOT */
+
+
+static const struct file_operations tracing_thresh_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_thresh_read,
+	.write		= tracing_thresh_write,
+	.llseek		= generic_file_llseek,
+};
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+static const struct file_operations tracing_max_lat_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= tracing_max_lat_read,
+	.write		= tracing_max_lat_write,
+	.llseek		= generic_file_llseek,
+	.release	= tracing_release_generic_tr,
+};
+#endif
+
+static const struct file_operations set_tracer_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= tracing_set_trace_read,
+	.write		= tracing_set_trace_write,
+	.llseek		= generic_file_llseek,
+	.release	= tracing_release_generic_tr,
+};
+
+static const struct file_operations tracing_pipe_fops = {
+	.open		= tracing_open_pipe,
+	.poll		= tracing_poll_pipe,
+	.read		= tracing_read_pipe,
+	.splice_read	= tracing_splice_read_pipe,
+	.release	= tracing_release_pipe,
+	.llseek		= no_llseek,
+};
+
+static const struct file_operations tracing_entries_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= tracing_entries_read,
+	.write		= tracing_entries_write,
+	.llseek		= generic_file_llseek,
+	.release	= tracing_release_generic_tr,
+};
+
+static const struct file_operations tracing_total_entries_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= tracing_total_entries_read,
+	.llseek		= generic_file_llseek,
+	.release	= tracing_release_generic_tr,
+};
+
+static const struct file_operations tracing_free_buffer_fops = {
+	.open		= tracing_open_generic_tr,
+	.write		= tracing_free_buffer_write,
+	.release	= tracing_free_buffer_release,
+};
+
+static const struct file_operations tracing_mark_fops = {
+	.open		= tracing_mark_open,
+	.write		= tracing_mark_write,
+	.release	= tracing_release_generic_tr,
+};
+
+static const struct file_operations tracing_mark_raw_fops = {
+	.open		= tracing_mark_open,
+	.write		= tracing_mark_raw_write,
+	.release	= tracing_release_generic_tr,
+};
+
+static const struct file_operations trace_clock_fops = {
+	.open		= tracing_clock_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= tracing_single_release_tr,
+	.write		= tracing_clock_write,
+};
+
+static const struct file_operations trace_time_stamp_mode_fops = {
+	.open		= tracing_time_stamp_mode_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= tracing_single_release_tr,
+};
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+static const struct file_operations snapshot_fops = {
+	.open		= tracing_snapshot_open,
+	.read		= seq_read,
+	.write		= tracing_snapshot_write,
+	.llseek		= tracing_lseek,
+	.release	= tracing_snapshot_release,
+};
+
+static const struct file_operations snapshot_raw_fops = {
+	.open		= snapshot_raw_open,
+	.read		= tracing_buffers_read,
+	.release	= tracing_buffers_release,
+	.splice_read	= tracing_buffers_splice_read,
+	.llseek		= no_llseek,
+};
+
+#endif /* CONFIG_TRACER_SNAPSHOT */
+
+/*
+ * trace_min_max_write - Write a u64 value to a trace_min_max_param struct
+ * @filp: The active open file structure
+ * @ubuf: The userspace provided buffer to read value into
+ * @cnt: The maximum number of bytes to read
+ * @ppos: The current "file" position
+ *
+ * This function implements the write interface for a struct trace_min_max_param.
+ * The filp->private_data must point to a trace_min_max_param structure that
+ * defines where to write the value, the min and the max acceptable values,
+ * and a lock to protect the write.
+ */
+static ssize_t
+trace_min_max_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos)
+{
+	struct trace_min_max_param *param = filp->private_data;
+	u64 val;
+	int err;
+
+	if (!param)
+		return -EFAULT;
+
+	err = kstrtoull_from_user(ubuf, cnt, 10, &val);
+	if (err)
+		return err;
+
+	if (param->lock)
+		mutex_lock(param->lock);
+
+	if (param->min && val < *param->min)
+		err = -EINVAL;
+
+	if (param->max && val > *param->max)
+		err = -EINVAL;
+
+	if (!err)
+		*param->val = val;
+
+	if (param->lock)
+		mutex_unlock(param->lock);
+
+	if (err)
+		return err;
+
+	return cnt;
+}
+
+/*
+ * trace_min_max_read - Read a u64 value from a trace_min_max_param struct
+ * @filp: The active open file structure
+ * @ubuf: The userspace provided buffer to read value into
+ * @cnt: The maximum number of bytes to read
+ * @ppos: The current "file" position
+ *
+ * This function implements the read interface for a struct trace_min_max_param.
+ * The filp->private_data must point to a trace_min_max_param struct with valid
+ * data.
+ */
+static ssize_t
+trace_min_max_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
+{
+	struct trace_min_max_param *param = filp->private_data;
+	char buf[U64_STR_SIZE];
+	int len;
+	u64 val;
+
+	if (!param)
+		return -EFAULT;
+
+	val = *param->val;
+
+	if (cnt > sizeof(buf))
+		cnt = sizeof(buf);
+
+	len = snprintf(buf, sizeof(buf), "%llu\n", val);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
+}
+
+const struct file_operations trace_min_max_fops = {
+	.open		= tracing_open_generic,
+	.read		= trace_min_max_read,
+	.write		= trace_min_max_write,
+};
+
+#define TRACING_LOG_ERRS_MAX	8
+#define TRACING_LOG_LOC_MAX	128
+
+#define CMD_PREFIX "  Command: "
+
+struct err_info {
+	const char	**errs;	/* ptr to loc-specific array of err strings */
+	u8		type;	/* index into errs -> specific err string */
+	u16		pos;	/* caret position */
+	u64		ts;
+};
+
+struct tracing_log_err {
+	struct list_head	list;
+	struct err_info		info;
+	char			loc[TRACING_LOG_LOC_MAX]; /* err location */
+	char			*cmd;                     /* what caused err */
+};
+
+static DEFINE_MUTEX(tracing_err_log_lock);
+
+static struct tracing_log_err *alloc_tracing_log_err(int len)
+{
+	struct tracing_log_err *err;
+
+	err = kzalloc(sizeof(*err), GFP_KERNEL);
+	if (!err)
+		return ERR_PTR(-ENOMEM);
+
+	err->cmd = kzalloc(len, GFP_KERNEL);
+	if (!err->cmd) {
+		kfree(err);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return err;
+}
+
+static void free_tracing_log_err(struct tracing_log_err *err)
+{
+	kfree(err->cmd);
+	kfree(err);
+}
+
+static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr,
+						   int len)
+{
+	struct tracing_log_err *err;
+	char *cmd;
+
+	if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) {
+		err = alloc_tracing_log_err(len);
+		if (PTR_ERR(err) != -ENOMEM)
+			tr->n_err_log_entries++;
+
+		return err;
+	}
+	cmd = kzalloc(len, GFP_KERNEL);
+	if (!cmd)
+		return ERR_PTR(-ENOMEM);
+	err = list_first_entry(&tr->err_log, struct tracing_log_err, list);
+	kfree(err->cmd);
+	err->cmd = cmd;
+	list_del(&err->list);
+
+	return err;
+}
+
+/**
+ * err_pos - find the position of a string within a command for error careting
+ * @cmd: The tracing command that caused the error
+ * @str: The string to position the caret at within @cmd
+ *
+ * Finds the position of the first occurrence of @str within @cmd.  The
+ * return value can be passed to tracing_log_err() for caret placement
+ * within @cmd.
+ *
+ * Returns the index within @cmd of the first occurrence of @str or 0
+ * if @str was not found.
+ */
+unsigned int err_pos(char *cmd, const char *str)
+{
+	char *found;
+
+	if (WARN_ON(!strlen(cmd)))
+		return 0;
+
+	found = strstr(cmd, str);
+	if (found)
+		return found - cmd;
+
+	return 0;
+}
+
+/**
+ * tracing_log_err - write an error to the tracing error log
+ * @tr: The associated trace array for the error (NULL for top level array)
+ * @loc: A string describing where the error occurred
+ * @cmd: The tracing command that caused the error
+ * @errs: The array of loc-specific static error strings
+ * @type: The index into errs[], which produces the specific static err string
+ * @pos: The position the caret should be placed in the cmd
+ *
+ * Writes an error into tracing/error_log of the form:
+ *
+ * <loc>: error: <text>
+ *   Command: <cmd>
+ *              ^
+ *
+ * tracing/error_log is a small log file containing the last
+ * TRACING_LOG_ERRS_MAX errors (8).  Memory for errors isn't allocated
+ * unless there has been a tracing error, and the error log can be
+ * cleared and have its memory freed by writing the empty string in
+ * truncation mode to it i.e. echo > tracing/error_log.
+ *
+ * NOTE: the @errs array along with the @type param are used to
+ * produce a static error string - this string is not copied and saved
+ * when the error is logged - only a pointer to it is saved.  See
+ * existing callers for examples of how static strings are typically
+ * defined for use with tracing_log_err().
+ */
+void tracing_log_err(struct trace_array *tr,
+		     const char *loc, const char *cmd,
+		     const char **errs, u8 type, u16 pos)
+{
+	struct tracing_log_err *err;
+	int len = 0;
+
+	if (!tr)
+		tr = &global_trace;
+
+	len += sizeof(CMD_PREFIX) + 2 * sizeof("\n") + strlen(cmd) + 1;
+
+	mutex_lock(&tracing_err_log_lock);
+	err = get_tracing_log_err(tr, len);
+	if (PTR_ERR(err) == -ENOMEM) {
+		mutex_unlock(&tracing_err_log_lock);
+		return;
+	}
+
+	snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc);
+	snprintf(err->cmd, len, "\n" CMD_PREFIX "%s\n", cmd);
+
+	err->info.errs = errs;
+	err->info.type = type;
+	err->info.pos = pos;
+	err->info.ts = local_clock();
+
+	list_add_tail(&err->list, &tr->err_log);
+	mutex_unlock(&tracing_err_log_lock);
+}
+
+static void clear_tracing_err_log(struct trace_array *tr)
+{
+	struct tracing_log_err *err, *next;
+
+	mutex_lock(&tracing_err_log_lock);
+	list_for_each_entry_safe(err, next, &tr->err_log, list) {
+		list_del(&err->list);
+		free_tracing_log_err(err);
+	}
+
+	tr->n_err_log_entries = 0;
+	mutex_unlock(&tracing_err_log_lock);
+}
+
+static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos)
+{
+	struct trace_array *tr = m->private;
+
+	mutex_lock(&tracing_err_log_lock);
+
+	return seq_list_start(&tr->err_log, *pos);
+}
+
+static void *tracing_err_log_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct trace_array *tr = m->private;
+
+	return seq_list_next(v, &tr->err_log, pos);
+}
+
+static void tracing_err_log_seq_stop(struct seq_file *m, void *v)
+{
+	mutex_unlock(&tracing_err_log_lock);
+}
+
+static void tracing_err_log_show_pos(struct seq_file *m, u16 pos)
+{
+	u16 i;
+
+	for (i = 0; i < sizeof(CMD_PREFIX) - 1; i++)
+		seq_putc(m, ' ');
+	for (i = 0; i < pos; i++)
+		seq_putc(m, ' ');
+	seq_puts(m, "^\n");
+}
+
+static int tracing_err_log_seq_show(struct seq_file *m, void *v)
+{
+	struct tracing_log_err *err = v;
+
+	if (err) {
+		const char *err_text = err->info.errs[err->info.type];
+		u64 sec = err->info.ts;
+		u32 nsec;
+
+		nsec = do_div(sec, NSEC_PER_SEC);
+		seq_printf(m, "[%5llu.%06u] %s%s", sec, nsec / 1000,
+			   err->loc, err_text);
+		seq_printf(m, "%s", err->cmd);
+		tracing_err_log_show_pos(m, err->info.pos);
+	}
+
+	return 0;
+}
+
+static const struct seq_operations tracing_err_log_seq_ops = {
+	.start  = tracing_err_log_seq_start,
+	.next   = tracing_err_log_seq_next,
+	.stop   = tracing_err_log_seq_stop,
+	.show   = tracing_err_log_seq_show
+};
+
+static int tracing_err_log_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	int ret = 0;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	/* If this file was opened for write, then erase contents */
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
+		clear_tracing_err_log(tr);
+
+	if (file->f_mode & FMODE_READ) {
+		ret = seq_open(file, &tracing_err_log_seq_ops);
+		if (!ret) {
+			struct seq_file *m = file->private_data;
+			m->private = tr;
+		} else {
+			trace_array_put(tr);
+		}
+	}
+	return ret;
+}
+
+static ssize_t tracing_err_log_write(struct file *file,
+				     const char __user *buffer,
+				     size_t count, loff_t *ppos)
+{
+	return count;
+}
+
+static int tracing_err_log_release(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+
+	trace_array_put(tr);
+
+	if (file->f_mode & FMODE_READ)
+		seq_release(inode, file);
+
+	return 0;
+}
+
+static const struct file_operations tracing_err_log_fops = {
+	.open           = tracing_err_log_open,
+	.write		= tracing_err_log_write,
+	.read           = seq_read,
+	.llseek         = tracing_lseek,
+	.release        = tracing_err_log_release,
+};
+
+static int tracing_buffers_open(struct inode *inode, struct file *filp)
+{
+	struct trace_array *tr = inode->i_private;
+	struct ftrace_buffer_info *info;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	info = kvzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		trace_array_put(tr);
+		return -ENOMEM;
+	}
+
+	mutex_lock(&trace_types_lock);
+
+	info->iter.tr		= tr;
+	info->iter.cpu_file	= tracing_get_cpu(inode);
+	info->iter.trace	= tr->current_trace;
+	info->iter.array_buffer = &tr->array_buffer;
+	info->spare		= NULL;
+	/* Force reading ring buffer for first read */
+	info->read		= (unsigned int)-1;
+
+	filp->private_data = info;
+
+	tr->trace_ref++;
+
+	mutex_unlock(&trace_types_lock);
+
+	ret = nonseekable_open(inode, filp);
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
+}
+
+static __poll_t
+tracing_buffers_poll(struct file *filp, poll_table *poll_table)
+{
+	struct ftrace_buffer_info *info = filp->private_data;
+	struct trace_iterator *iter = &info->iter;
+
+	return trace_poll(iter, filp, poll_table);
+}
+
+static ssize_t
+tracing_buffers_read(struct file *filp, char __user *ubuf,
+		     size_t count, loff_t *ppos)
+{
+	struct ftrace_buffer_info *info = filp->private_data;
+	struct trace_iterator *iter = &info->iter;
+	ssize_t ret = 0;
+	ssize_t size;
+
+	if (!count)
+		return 0;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (iter->snapshot && iter->tr->current_trace->use_max_tr)
+		return -EBUSY;
+#endif
+
+	if (!info->spare) {
+		info->spare = ring_buffer_alloc_read_page(iter->array_buffer->buffer,
+							  iter->cpu_file);
+		if (IS_ERR(info->spare)) {
+			ret = PTR_ERR(info->spare);
+			info->spare = NULL;
+		} else {
+			info->spare_cpu = iter->cpu_file;
+		}
+	}
+	if (!info->spare)
+		return ret;
+
+	/* Do we have previous read data to read? */
+	if (info->read < PAGE_SIZE)
+		goto read;
+
+ again:
+	trace_access_lock(iter->cpu_file);
+	ret = ring_buffer_read_page(iter->array_buffer->buffer,
+				    &info->spare,
+				    count,
+				    iter->cpu_file, 0);
+	trace_access_unlock(iter->cpu_file);
+
+	if (ret < 0) {
+		if (trace_empty(iter)) {
+			if ((filp->f_flags & O_NONBLOCK))
+				return -EAGAIN;
+
+			ret = wait_on_pipe(iter, 0);
+			if (ret)
+				return ret;
+
+			goto again;
+		}
+		return 0;
+	}
+
+	info->read = 0;
+ read:
+	size = PAGE_SIZE - info->read;
+	if (size > count)
+		size = count;
+
+	ret = copy_to_user(ubuf, info->spare + info->read, size);
+	if (ret == size)
+		return -EFAULT;
+
+	size -= ret;
+
+	*ppos += size;
+	info->read += size;
+
+	return size;
+}
+
+static int tracing_buffers_release(struct inode *inode, struct file *file)
+{
+	struct ftrace_buffer_info *info = file->private_data;
+	struct trace_iterator *iter = &info->iter;
+
+	mutex_lock(&trace_types_lock);
+
+	iter->tr->trace_ref--;
+
+	__trace_array_put(iter->tr);
+
+	iter->wait_index++;
+	/* Make sure the waiters see the new wait_index */
+	smp_wmb();
+
+	ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
+
+	if (info->spare)
+		ring_buffer_free_read_page(iter->array_buffer->buffer,
+					   info->spare_cpu, info->spare);
+	kvfree(info);
+
+	mutex_unlock(&trace_types_lock);
+
+	return 0;
+}
+
+struct buffer_ref {
+	struct trace_buffer	*buffer;
+	void			*page;
+	int			cpu;
+	refcount_t		refcount;
+};
+
+static void buffer_ref_release(struct buffer_ref *ref)
+{
+	if (!refcount_dec_and_test(&ref->refcount))
+		return;
+	ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
+	kfree(ref);
+}
+
+static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
+				    struct pipe_buffer *buf)
+{
+	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
+
+	buffer_ref_release(ref);
+	buf->private = 0;
+}
+
+static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
+				struct pipe_buffer *buf)
+{
+	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
+
+	if (refcount_read(&ref->refcount) > INT_MAX/2)
+		return false;
+
+	refcount_inc(&ref->refcount);
+	return true;
+}
+
+/* Pipe buffer operations for a buffer. */
+static const struct pipe_buf_operations buffer_pipe_buf_ops = {
+	.release		= buffer_pipe_buf_release,
+	.get			= buffer_pipe_buf_get,
+};
+
+/*
+ * Callback from splice_to_pipe(), if we need to release some pages
+ * at the end of the spd in case we error'ed out in filling the pipe.
+ */
+static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
+{
+	struct buffer_ref *ref =
+		(struct buffer_ref *)spd->partial[i].private;
+
+	buffer_ref_release(ref);
+	spd->partial[i].private = 0;
+}
+
+static ssize_t
+tracing_buffers_splice_read(struct file *file, loff_t *ppos,
+			    struct pipe_inode_info *pipe, size_t len,
+			    unsigned int flags)
+{
+	struct ftrace_buffer_info *info = file->private_data;
+	struct trace_iterator *iter = &info->iter;
+	struct partial_page partial_def[PIPE_DEF_BUFFERS];
+	struct page *pages_def[PIPE_DEF_BUFFERS];
+	struct splice_pipe_desc spd = {
+		.pages		= pages_def,
+		.partial	= partial_def,
+		.nr_pages_max	= PIPE_DEF_BUFFERS,
+		.ops		= &buffer_pipe_buf_ops,
+		.spd_release	= buffer_spd_release,
+	};
+	struct buffer_ref *ref;
+	int entries, i;
+	ssize_t ret = 0;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (iter->snapshot && iter->tr->current_trace->use_max_tr)
+		return -EBUSY;
+#endif
+
+	if (*ppos & (PAGE_SIZE - 1))
+		return -EINVAL;
+
+	if (len & (PAGE_SIZE - 1)) {
+		if (len < PAGE_SIZE)
+			return -EINVAL;
+		len &= PAGE_MASK;
+	}
+
+	if (splice_grow_spd(pipe, &spd))
+		return -ENOMEM;
+
+ again:
+	trace_access_lock(iter->cpu_file);
+	entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
+
+	for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
+		struct page *page;
+		int r;
+
+		ref = kzalloc(sizeof(*ref), GFP_KERNEL);
+		if (!ref) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		refcount_set(&ref->refcount, 1);
+		ref->buffer = iter->array_buffer->buffer;
+		ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
+		if (IS_ERR(ref->page)) {
+			ret = PTR_ERR(ref->page);
+			ref->page = NULL;
+			kfree(ref);
+			break;
+		}
+		ref->cpu = iter->cpu_file;
+
+		r = ring_buffer_read_page(ref->buffer, &ref->page,
+					  len, iter->cpu_file, 1);
+		if (r < 0) {
+			ring_buffer_free_read_page(ref->buffer, ref->cpu,
+						   ref->page);
+			kfree(ref);
+			break;
+		}
+
+		page = virt_to_page(ref->page);
+
+		spd.pages[i] = page;
+		spd.partial[i].len = PAGE_SIZE;
+		spd.partial[i].offset = 0;
+		spd.partial[i].private = (unsigned long)ref;
+		spd.nr_pages++;
+		*ppos += PAGE_SIZE;
+
+		entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
+	}
+
+	trace_access_unlock(iter->cpu_file);
+	spd.nr_pages = i;
+
+	/* did we read anything? */
+	if (!spd.nr_pages) {
+		long wait_index;
+
+		if (ret)
+			goto out;
+
+		ret = -EAGAIN;
+		if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
+			goto out;
+
+		wait_index = READ_ONCE(iter->wait_index);
+
+		ret = wait_on_pipe(iter, iter->snapshot ? 0 : iter->tr->buffer_percent);
+		if (ret)
+			goto out;
+
+		/* No need to wait after waking up when tracing is off */
+		if (!tracer_tracing_is_on(iter->tr))
+			goto out;
+
+		/* Make sure we see the new wait_index */
+		smp_rmb();
+		if (wait_index != iter->wait_index)
+			goto out;
+
+		goto again;
+	}
+
+	ret = splice_to_pipe(pipe, &spd);
+out:
+	splice_shrink_spd(&spd);
+
+	return ret;
+}
+
+/* An ioctl call with cmd 0 to the ring buffer file will wake up all waiters */
+static long tracing_buffers_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct ftrace_buffer_info *info = file->private_data;
+	struct trace_iterator *iter = &info->iter;
+
+	if (cmd)
+		return -ENOIOCTLCMD;
+
+	mutex_lock(&trace_types_lock);
+
+	iter->wait_index++;
+	/* Make sure the waiters see the new wait_index */
+	smp_wmb();
+
+	ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
+
+	mutex_unlock(&trace_types_lock);
+	return 0;
+}
+
+static const struct file_operations tracing_buffers_fops = {
+	.open		= tracing_buffers_open,
+	.read		= tracing_buffers_read,
+	.poll		= tracing_buffers_poll,
+	.release	= tracing_buffers_release,
+	.splice_read	= tracing_buffers_splice_read,
+	.unlocked_ioctl = tracing_buffers_ioctl,
+	.llseek		= no_llseek,
+};
+
+static ssize_t
+tracing_stats_read(struct file *filp, char __user *ubuf,
+		   size_t count, loff_t *ppos)
+{
+	struct inode *inode = file_inode(filp);
+	struct trace_array *tr = inode->i_private;
+	struct array_buffer *trace_buf = &tr->array_buffer;
+	int cpu = tracing_get_cpu(inode);
+	struct trace_seq *s;
+	unsigned long cnt;
+	unsigned long long t;
+	unsigned long usec_rem;
+
+	s = kmalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	trace_seq_init(s);
+
+	cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
+	trace_seq_printf(s, "entries: %ld\n", cnt);
+
+	cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
+	trace_seq_printf(s, "overrun: %ld\n", cnt);
+
+	cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
+	trace_seq_printf(s, "commit overrun: %ld\n", cnt);
+
+	cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
+	trace_seq_printf(s, "bytes: %ld\n", cnt);
+
+	if (trace_clocks[tr->clock_id].in_ns) {
+		/* local or global for trace_clock */
+		t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
+		usec_rem = do_div(t, USEC_PER_SEC);
+		trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
+								t, usec_rem);
+
+		t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer));
+		usec_rem = do_div(t, USEC_PER_SEC);
+		trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
+	} else {
+		/* counter or tsc mode for trace_clock */
+		trace_seq_printf(s, "oldest event ts: %llu\n",
+				ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
+
+		trace_seq_printf(s, "now ts: %llu\n",
+				ring_buffer_time_stamp(trace_buf->buffer));
+	}
+
+	cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
+	trace_seq_printf(s, "dropped events: %ld\n", cnt);
+
+	cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
+	trace_seq_printf(s, "read events: %ld\n", cnt);
+
+	count = simple_read_from_buffer(ubuf, count, ppos,
+					s->buffer, trace_seq_used(s));
+
+	kfree(s);
+
+	return count;
+}
+
+static const struct file_operations tracing_stats_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= tracing_stats_read,
+	.llseek		= generic_file_llseek,
+	.release	= tracing_release_generic_tr,
+};
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+static ssize_t
+tracing_read_dyn_info(struct file *filp, char __user *ubuf,
+		  size_t cnt, loff_t *ppos)
+{
+	ssize_t ret;
+	char *buf;
+	int r;
+
+	/* 256 should be plenty to hold the amount needed */
+	buf = kmalloc(256, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	r = scnprintf(buf, 256, "%ld pages:%ld groups: %ld\n",
+		      ftrace_update_tot_cnt,
+		      ftrace_number_of_pages,
+		      ftrace_number_of_groups);
+
+	ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+	kfree(buf);
+	return ret;
+}
+
+static const struct file_operations tracing_dyn_info_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_read_dyn_info,
+	.llseek		= generic_file_llseek,
+};
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
+static void
+ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
+		struct trace_array *tr, struct ftrace_probe_ops *ops,
+		void *data)
+{
+	tracing_snapshot_instance(tr);
+}
+
+static void
+ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
+		      struct trace_array *tr, struct ftrace_probe_ops *ops,
+		      void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+	long *count = NULL;
+
+	if (mapper)
+		count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
+
+	if (count) {
+
+		if (*count <= 0)
+			return;
+
+		(*count)--;
+	}
+
+	tracing_snapshot_instance(tr);
+}
+
+static int
+ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
+		      struct ftrace_probe_ops *ops, void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+	long *count = NULL;
+
+	seq_printf(m, "%ps:", (void *)ip);
+
+	seq_puts(m, "snapshot");
+
+	if (mapper)
+		count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
+
+	if (count)
+		seq_printf(m, ":count=%ld\n", *count);
+	else
+		seq_puts(m, ":unlimited\n");
+
+	return 0;
+}
+
+static int
+ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
+		     unsigned long ip, void *init_data, void **data)
+{
+	struct ftrace_func_mapper *mapper = *data;
+
+	if (!mapper) {
+		mapper = allocate_ftrace_func_mapper();
+		if (!mapper)
+			return -ENOMEM;
+		*data = mapper;
+	}
+
+	return ftrace_func_mapper_add_ip(mapper, ip, init_data);
+}
+
+static void
+ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
+		     unsigned long ip, void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+
+	if (!ip) {
+		if (!mapper)
+			return;
+		free_ftrace_func_mapper(mapper, NULL);
+		return;
+	}
+
+	ftrace_func_mapper_remove_ip(mapper, ip);
+}
+
+static struct ftrace_probe_ops snapshot_probe_ops = {
+	.func			= ftrace_snapshot,
+	.print			= ftrace_snapshot_print,
+};
+
+static struct ftrace_probe_ops snapshot_count_probe_ops = {
+	.func			= ftrace_count_snapshot,
+	.print			= ftrace_snapshot_print,
+	.init			= ftrace_snapshot_init,
+	.free			= ftrace_snapshot_free,
+};
+
+static int
+ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
+			       char *glob, char *cmd, char *param, int enable)
+{
+	struct ftrace_probe_ops *ops;
+	void *count = (void *)-1;
+	char *number;
+	int ret;
+
+	if (!tr)
+		return -ENODEV;
+
+	/* hash funcs only work with set_ftrace_filter */
+	if (!enable)
+		return -EINVAL;
+
+	ops = param ? &snapshot_count_probe_ops :  &snapshot_probe_ops;
+
+	if (glob[0] == '!')
+		return unregister_ftrace_function_probe_func(glob+1, tr, ops);
+
+	if (!param)
+		goto out_reg;
+
+	number = strsep(&param, ":");
+
+	if (!strlen(number))
+		goto out_reg;
+
+	/*
+	 * We use the callback data field (which is a pointer)
+	 * as our counter.
+	 */
+	ret = kstrtoul(number, 0, (unsigned long *)&count);
+	if (ret)
+		return ret;
+
+ out_reg:
+	ret = tracing_alloc_snapshot_instance(tr);
+	if (ret < 0)
+		goto out;
+
+	ret = register_ftrace_function_probe(glob, tr, ops, count);
+
+ out:
+	return ret < 0 ? ret : 0;
+}
+
+static struct ftrace_func_command ftrace_snapshot_cmd = {
+	.name			= "snapshot",
+	.func			= ftrace_trace_snapshot_callback,
+};
+
+static __init int register_snapshot_cmd(void)
+{
+	return register_ftrace_command(&ftrace_snapshot_cmd);
+}
+#else
+static inline __init int register_snapshot_cmd(void) { return 0; }
+#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
+
+static struct dentry *tracing_get_dentry(struct trace_array *tr)
+{
+	if (WARN_ON(!tr->dir))
+		return ERR_PTR(-ENODEV);
+
+	/* Top directory uses NULL as the parent */
+	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
+		return NULL;
+
+	/* All sub buffers have a descriptor */
+	return tr->dir;
+}
+
+static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
+{
+	struct dentry *d_tracer;
+
+	if (tr->percpu_dir)
+		return tr->percpu_dir;
+
+	d_tracer = tracing_get_dentry(tr);
+	if (IS_ERR(d_tracer))
+		return NULL;
+
+	tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
+
+	MEM_FAIL(!tr->percpu_dir,
+		  "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
+
+	return tr->percpu_dir;
+}
+
+static struct dentry *
+trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
+		      void *data, long cpu, const struct file_operations *fops)
+{
+	struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
+
+	if (ret) /* See tracing_get_cpu() */
+		d_inode(ret)->i_cdev = (void *)(cpu + 1);
+	return ret;
+}
+
+static void
+tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
+{
+	struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
+	struct dentry *d_cpu;
+	char cpu_dir[30]; /* 30 characters should be more than enough */
+
+	if (!d_percpu)
+		return;
+
+	snprintf(cpu_dir, 30, "cpu%ld", cpu);
+	d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
+	if (!d_cpu) {
+		pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
+		return;
+	}
+
+	/* per cpu trace_pipe */
+	trace_create_cpu_file("trace_pipe", TRACE_MODE_READ, d_cpu,
+				tr, cpu, &tracing_pipe_fops);
+
+	/* per cpu trace */
+	trace_create_cpu_file("trace", TRACE_MODE_WRITE, d_cpu,
+				tr, cpu, &tracing_fops);
+
+	trace_create_cpu_file("trace_pipe_raw", TRACE_MODE_READ, d_cpu,
+				tr, cpu, &tracing_buffers_fops);
+
+	trace_create_cpu_file("stats", TRACE_MODE_READ, d_cpu,
+				tr, cpu, &tracing_stats_fops);
+
+	trace_create_cpu_file("buffer_size_kb", TRACE_MODE_READ, d_cpu,
+				tr, cpu, &tracing_entries_fops);
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+	trace_create_cpu_file("snapshot", TRACE_MODE_WRITE, d_cpu,
+				tr, cpu, &snapshot_fops);
+
+	trace_create_cpu_file("snapshot_raw", TRACE_MODE_READ, d_cpu,
+				tr, cpu, &snapshot_raw_fops);
+#endif
+}
+
+#ifdef CONFIG_FTRACE_SELFTEST
+/* Let selftest have access to static functions in this file */
+#include "trace_selftest.c"
+#endif
+
+static ssize_t
+trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
+			loff_t *ppos)
+{
+	struct trace_option_dentry *topt = filp->private_data;
+	char *buf;
+
+	if (topt->flags->val & topt->opt->bit)
+		buf = "1\n";
+	else
+		buf = "0\n";
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
+}
+
+static ssize_t
+trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
+			 loff_t *ppos)
+{
+	struct trace_option_dentry *topt = filp->private_data;
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	if (val != 0 && val != 1)
+		return -EINVAL;
+
+	if (!!(topt->flags->val & topt->opt->bit) != val) {
+		mutex_lock(&trace_types_lock);
+		ret = __set_tracer_option(topt->tr, topt->flags,
+					  topt->opt, !val);
+		mutex_unlock(&trace_types_lock);
+		if (ret)
+			return ret;
+	}
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static int tracing_open_options(struct inode *inode, struct file *filp)
+{
+	struct trace_option_dentry *topt = inode->i_private;
+	int ret;
+
+	ret = tracing_check_open_get_tr(topt->tr);
+	if (ret)
+		return ret;
+
+	filp->private_data = inode->i_private;
+	return 0;
+}
+
+static int tracing_release_options(struct inode *inode, struct file *file)
+{
+	struct trace_option_dentry *topt = file->private_data;
+
+	trace_array_put(topt->tr);
+	return 0;
+}
+
+static const struct file_operations trace_options_fops = {
+	.open = tracing_open_options,
+	.read = trace_options_read,
+	.write = trace_options_write,
+	.llseek	= generic_file_llseek,
+	.release = tracing_release_options,
+};
+
+/*
+ * In order to pass in both the trace_array descriptor as well as the index
+ * to the flag that the trace option file represents, the trace_array
+ * has a character array of trace_flags_index[], which holds the index
+ * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
+ * The address of this character array is passed to the flag option file
+ * read/write callbacks.
+ *
+ * In order to extract both the index and the trace_array descriptor,
+ * get_tr_index() uses the following algorithm.
+ *
+ *   idx = *ptr;
+ *
+ * As the pointer itself contains the address of the index (remember
+ * index[1] == 1).
+ *
+ * Then to get the trace_array descriptor, by subtracting that index
+ * from the ptr, we get to the start of the index itself.
+ *
+ *   ptr - idx == &index[0]
+ *
+ * Then a simple container_of() from that pointer gets us to the
+ * trace_array descriptor.
+ */
+static void get_tr_index(void *data, struct trace_array **ptr,
+			 unsigned int *pindex)
+{
+	*pindex = *(unsigned char *)data;
+
+	*ptr = container_of(data - *pindex, struct trace_array,
+			    trace_flags_index);
+}
+
+static ssize_t
+trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
+			loff_t *ppos)
+{
+	void *tr_index = filp->private_data;
+	struct trace_array *tr;
+	unsigned int index;
+	char *buf;
+
+	get_tr_index(tr_index, &tr, &index);
+
+	if (tr->trace_flags & (1 << index))
+		buf = "1\n";
+	else
+		buf = "0\n";
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
+}
+
+static ssize_t
+trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
+			 loff_t *ppos)
+{
+	void *tr_index = filp->private_data;
+	struct trace_array *tr;
+	unsigned int index;
+	unsigned long val;
+	int ret;
+
+	get_tr_index(tr_index, &tr, &index);
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	if (val != 0 && val != 1)
+		return -EINVAL;
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+	ret = set_tracer_flag(tr, 1 << index, val);
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+
+	if (ret < 0)
+		return ret;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static const struct file_operations trace_options_core_fops = {
+	.open = tracing_open_generic,
+	.read = trace_options_core_read,
+	.write = trace_options_core_write,
+	.llseek = generic_file_llseek,
+};
+
+struct dentry *trace_create_file(const char *name,
+				 umode_t mode,
+				 struct dentry *parent,
+				 void *data,
+				 const struct file_operations *fops)
+{
+	struct dentry *ret;
+
+	ret = tracefs_create_file(name, mode, parent, data, fops);
+	if (!ret)
+		pr_warn("Could not create tracefs '%s' entry\n", name);
+
+	return ret;
+}
+
+
+static struct dentry *trace_options_init_dentry(struct trace_array *tr)
+{
+	struct dentry *d_tracer;
+
+	if (tr->options)
+		return tr->options;
+
+	d_tracer = tracing_get_dentry(tr);
+	if (IS_ERR(d_tracer))
+		return NULL;
+
+	tr->options = tracefs_create_dir("options", d_tracer);
+	if (!tr->options) {
+		pr_warn("Could not create tracefs directory 'options'\n");
+		return NULL;
+	}
+
+	return tr->options;
+}
+
+static void
+create_trace_option_file(struct trace_array *tr,
+			 struct trace_option_dentry *topt,
+			 struct tracer_flags *flags,
+			 struct tracer_opt *opt)
+{
+	struct dentry *t_options;
+
+	t_options = trace_options_init_dentry(tr);
+	if (!t_options)
+		return;
+
+	topt->flags = flags;
+	topt->opt = opt;
+	topt->tr = tr;
+
+	topt->entry = trace_create_file(opt->name, TRACE_MODE_WRITE,
+					t_options, topt, &trace_options_fops);
+
+}
+
+static void
+create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
+{
+	struct trace_option_dentry *topts;
+	struct trace_options *tr_topts;
+	struct tracer_flags *flags;
+	struct tracer_opt *opts;
+	int cnt;
+	int i;
+
+	if (!tracer)
+		return;
+
+	flags = tracer->flags;
+
+	if (!flags || !flags->opts)
+		return;
+
+	/*
+	 * If this is an instance, only create flags for tracers
+	 * the instance may have.
+	 */
+	if (!trace_ok_for_array(tracer, tr))
+		return;
+
+	for (i = 0; i < tr->nr_topts; i++) {
+		/* Make sure there's no duplicate flags. */
+		if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
+			return;
+	}
+
+	opts = flags->opts;
+
+	for (cnt = 0; opts[cnt].name; cnt++)
+		;
+
+	topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
+	if (!topts)
+		return;
+
+	tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
+			    GFP_KERNEL);
+	if (!tr_topts) {
+		kfree(topts);
+		return;
+	}
+
+	tr->topts = tr_topts;
+	tr->topts[tr->nr_topts].tracer = tracer;
+	tr->topts[tr->nr_topts].topts = topts;
+	tr->nr_topts++;
+
+	for (cnt = 0; opts[cnt].name; cnt++) {
+		create_trace_option_file(tr, &topts[cnt], flags,
+					 &opts[cnt]);
+		MEM_FAIL(topts[cnt].entry == NULL,
+			  "Failed to create trace option: %s",
+			  opts[cnt].name);
+	}
+}
+
+static struct dentry *
+create_trace_option_core_file(struct trace_array *tr,
+			      const char *option, long index)
+{
+	struct dentry *t_options;
+
+	t_options = trace_options_init_dentry(tr);
+	if (!t_options)
+		return NULL;
+
+	return trace_create_file(option, TRACE_MODE_WRITE, t_options,
+				 (void *)&tr->trace_flags_index[index],
+				 &trace_options_core_fops);
+}
+
+static void create_trace_options_dir(struct trace_array *tr)
+{
+	struct dentry *t_options;
+	bool top_level = tr == &global_trace;
+	int i;
+
+	t_options = trace_options_init_dentry(tr);
+	if (!t_options)
+		return;
+
+	for (i = 0; trace_options[i]; i++) {
+		if (top_level ||
+		    !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
+			create_trace_option_core_file(tr, trace_options[i], i);
+	}
+}
+
+static ssize_t
+rb_simple_read(struct file *filp, char __user *ubuf,
+	       size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	char buf[64];
+	int r;
+
+	r = tracer_tracing_is_on(tr);
+	r = sprintf(buf, "%d\n", r);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+rb_simple_write(struct file *filp, const char __user *ubuf,
+		size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	struct trace_buffer *buffer = tr->array_buffer.buffer;
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	if (buffer) {
+		mutex_lock(&trace_types_lock);
+		if (!!val == tracer_tracing_is_on(tr)) {
+			val = 0; /* do nothing */
+		} else if (val) {
+			tracer_tracing_on(tr);
+			if (tr->current_trace->start)
+				tr->current_trace->start(tr);
+		} else {
+			tracer_tracing_off(tr);
+			if (tr->current_trace->stop)
+				tr->current_trace->stop(tr);
+			/* Wake up any waiters */
+			ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS);
+		}
+		mutex_unlock(&trace_types_lock);
+	}
+
+	(*ppos)++;
+
+	return cnt;
+}
+
+static const struct file_operations rb_simple_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= rb_simple_read,
+	.write		= rb_simple_write,
+	.release	= tracing_release_generic_tr,
+	.llseek		= default_llseek,
+};
+
+static ssize_t
+buffer_percent_read(struct file *filp, char __user *ubuf,
+		    size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	char buf[64];
+	int r;
+
+	r = tr->buffer_percent;
+	r = sprintf(buf, "%d\n", r);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+buffer_percent_write(struct file *filp, const char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	if (val > 100)
+		return -EINVAL;
+
+	tr->buffer_percent = val;
+
+	(*ppos)++;
+
+	return cnt;
+}
+
+static const struct file_operations buffer_percent_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= buffer_percent_read,
+	.write		= buffer_percent_write,
+	.release	= tracing_release_generic_tr,
+	.llseek		= default_llseek,
+};
+
+static struct dentry *trace_instance_dir;
+
+static void
+init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
+
+static int
+allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size)
+{
+	enum ring_buffer_flags rb_flags;
+
+	rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
+
+	buf->tr = tr;
+
+	buf->buffer = ring_buffer_alloc(size, rb_flags);
+	if (!buf->buffer)
+		return -ENOMEM;
+
+	buf->data = alloc_percpu(struct trace_array_cpu);
+	if (!buf->data) {
+		ring_buffer_free(buf->buffer);
+		buf->buffer = NULL;
+		return -ENOMEM;
+	}
+
+	/* Allocate the first page for all buffers */
+	set_buffer_entries(&tr->array_buffer,
+			   ring_buffer_size(tr->array_buffer.buffer, 0));
+
+	return 0;
+}
+
+static void free_trace_buffer(struct array_buffer *buf)
+{
+	if (buf->buffer) {
+		ring_buffer_free(buf->buffer);
+		buf->buffer = NULL;
+		free_percpu(buf->data);
+		buf->data = NULL;
+	}
+}
+
+static int allocate_trace_buffers(struct trace_array *tr, int size)
+{
+	int ret;
+
+	ret = allocate_trace_buffer(tr, &tr->array_buffer, size);
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	ret = allocate_trace_buffer(tr, &tr->max_buffer,
+				    allocate_snapshot ? size : 1);
+	if (MEM_FAIL(ret, "Failed to allocate trace buffer\n")) {
+		free_trace_buffer(&tr->array_buffer);
+		return -ENOMEM;
+	}
+	tr->allocated_snapshot = allocate_snapshot;
+
+	/*
+	 * Only the top level trace array gets its snapshot allocated
+	 * from the kernel command line.
+	 */
+	allocate_snapshot = false;
+#endif
+
+	return 0;
+}
+
+static void free_trace_buffers(struct trace_array *tr)
+{
+	if (!tr)
+		return;
+
+	free_trace_buffer(&tr->array_buffer);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	free_trace_buffer(&tr->max_buffer);
+#endif
+}
+
+static void init_trace_flags_index(struct trace_array *tr)
+{
+	int i;
+
+	/* Used by the trace options files */
+	for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
+		tr->trace_flags_index[i] = i;
+}
+
+static void __update_tracer_options(struct trace_array *tr)
+{
+	struct tracer *t;
+
+	for (t = trace_types; t; t = t->next)
+		add_tracer_options(tr, t);
+}
+
+static void update_tracer_options(struct trace_array *tr)
+{
+	mutex_lock(&trace_types_lock);
+	tracer_options_updated = true;
+	__update_tracer_options(tr);
+	mutex_unlock(&trace_types_lock);
+}
+
+/* Must have trace_types_lock held */
+struct trace_array *trace_array_find(const char *instance)
+{
+	struct trace_array *tr, *found = NULL;
+
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (tr->name && strcmp(tr->name, instance) == 0) {
+			found = tr;
+			break;
+		}
+	}
+
+	return found;
+}
+
+struct trace_array *trace_array_find_get(const char *instance)
+{
+	struct trace_array *tr;
+
+	mutex_lock(&trace_types_lock);
+	tr = trace_array_find(instance);
+	if (tr)
+		tr->ref++;
+	mutex_unlock(&trace_types_lock);
+
+	return tr;
+}
+
+static int trace_array_create_dir(struct trace_array *tr)
+{
+	int ret;
+
+	tr->dir = tracefs_create_dir(tr->name, trace_instance_dir);
+	if (!tr->dir)
+		return -EINVAL;
+
+	ret = event_trace_add_tracer(tr->dir, tr);
+	if (ret) {
+		tracefs_remove(tr->dir);
+		return ret;
+	}
+
+	init_tracer_tracefs(tr, tr->dir);
+	__update_tracer_options(tr);
+
+	return ret;
+}
+
+static struct trace_array *trace_array_create(const char *name)
+{
+	struct trace_array *tr;
+	int ret;
+
+	ret = -ENOMEM;
+	tr = kzalloc(sizeof(*tr), GFP_KERNEL);
+	if (!tr)
+		return ERR_PTR(ret);
+
+	tr->name = kstrdup(name, GFP_KERNEL);
+	if (!tr->name)
+		goto out_free_tr;
+
+	if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
+		goto out_free_tr;
+
+	if (!zalloc_cpumask_var(&tr->pipe_cpumask, GFP_KERNEL))
+		goto out_free_tr;
+
+	tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
+
+	cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
+
+	raw_spin_lock_init(&tr->start_lock);
+
+	tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+
+	tr->current_trace = &nop_trace;
+
+	INIT_LIST_HEAD(&tr->systems);
+	INIT_LIST_HEAD(&tr->events);
+	INIT_LIST_HEAD(&tr->hist_vars);
+	INIT_LIST_HEAD(&tr->err_log);
+
+	if (allocate_trace_buffers(tr, trace_buf_size) < 0)
+		goto out_free_tr;
+
+	if (ftrace_allocate_ftrace_ops(tr) < 0)
+		goto out_free_tr;
+
+	ftrace_init_trace_array(tr);
+
+	init_trace_flags_index(tr);
+
+	if (trace_instance_dir) {
+		ret = trace_array_create_dir(tr);
+		if (ret)
+			goto out_free_tr;
+	} else
+		__trace_early_add_events(tr);
+
+	list_add(&tr->list, &ftrace_trace_arrays);
+
+	tr->ref++;
+
+	return tr;
+
+ out_free_tr:
+	ftrace_free_ftrace_ops(tr);
+	free_trace_buffers(tr);
+	free_cpumask_var(tr->pipe_cpumask);
+	free_cpumask_var(tr->tracing_cpumask);
+	kfree(tr->name);
+	kfree(tr);
+
+	return ERR_PTR(ret);
+}
+
+static int instance_mkdir(const char *name)
+{
+	struct trace_array *tr;
+	int ret;
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+
+	ret = -EEXIST;
+	if (trace_array_find(name))
+		goto out_unlock;
+
+	tr = trace_array_create(name);
+
+	ret = PTR_ERR_OR_ZERO(tr);
+
+out_unlock:
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+	return ret;
+}
+
+/**
+ * trace_array_get_by_name - Create/Lookup a trace array, given its name.
+ * @name: The name of the trace array to be looked up/created.
+ *
+ * Returns pointer to trace array with given name.
+ * NULL, if it cannot be created.
+ *
+ * NOTE: This function increments the reference counter associated with the
+ * trace array returned. This makes sure it cannot be freed while in use.
+ * Use trace_array_put() once the trace array is no longer needed.
+ * If the trace_array is to be freed, trace_array_destroy() needs to
+ * be called after the trace_array_put(), or simply let user space delete
+ * it from the tracefs instances directory. But until the
+ * trace_array_put() is called, user space can not delete it.
+ *
+ */
+struct trace_array *trace_array_get_by_name(const char *name)
+{
+	struct trace_array *tr;
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (tr->name && strcmp(tr->name, name) == 0)
+			goto out_unlock;
+	}
+
+	tr = trace_array_create(name);
+
+	if (IS_ERR(tr))
+		tr = NULL;
+out_unlock:
+	if (tr)
+		tr->ref++;
+
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+	return tr;
+}
+EXPORT_SYMBOL_GPL(trace_array_get_by_name);
+
+static int __remove_instance(struct trace_array *tr)
+{
+	int i;
+
+	/* Reference counter for a newly created trace array = 1. */
+	if (tr->ref > 1 || (tr->current_trace && tr->trace_ref))
+		return -EBUSY;
+
+	list_del(&tr->list);
+
+	/* Disable all the flags that were enabled coming in */
+	for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
+		if ((1 << i) & ZEROED_TRACE_FLAGS)
+			set_tracer_flag(tr, 1 << i, 0);
+	}
+
+	tracing_set_nop(tr);
+	clear_ftrace_function_probes(tr);
+	event_trace_del_tracer(tr);
+	ftrace_clear_pids(tr);
+	ftrace_destroy_function_files(tr);
+	tracefs_remove(tr->dir);
+	free_percpu(tr->last_func_repeats);
+	free_trace_buffers(tr);
+	clear_tracing_err_log(tr);
+
+	for (i = 0; i < tr->nr_topts; i++) {
+		kfree(tr->topts[i].topts);
+	}
+	kfree(tr->topts);
+
+	free_cpumask_var(tr->pipe_cpumask);
+	free_cpumask_var(tr->tracing_cpumask);
+	kfree(tr->name);
+	kfree(tr);
+
+	return 0;
+}
+
+int trace_array_destroy(struct trace_array *this_tr)
+{
+	struct trace_array *tr;
+	int ret;
+
+	if (!this_tr)
+		return -EINVAL;
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+
+	ret = -ENODEV;
+
+	/* Making sure trace array exists before destroying it. */
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (tr == this_tr) {
+			ret = __remove_instance(tr);
+			break;
+		}
+	}
+
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(trace_array_destroy);
+
+static int instance_rmdir(const char *name)
+{
+	struct trace_array *tr;
+	int ret;
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+
+	ret = -ENODEV;
+	tr = trace_array_find(name);
+	if (tr)
+		ret = __remove_instance(tr);
+
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+static __init void create_trace_instances(struct dentry *d_tracer)
+{
+	struct trace_array *tr;
+
+	trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
+							 instance_mkdir,
+							 instance_rmdir);
+	if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n"))
+		return;
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (!tr->name)
+			continue;
+		if (MEM_FAIL(trace_array_create_dir(tr) < 0,
+			     "Failed to create instance directory\n"))
+			break;
+	}
+
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+}
+
+static void
+init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
+{
+	struct trace_event_file *file;
+	int cpu;
+
+	trace_create_file("available_tracers", TRACE_MODE_READ, d_tracer,
+			tr, &show_traces_fops);
+
+	trace_create_file("current_tracer", TRACE_MODE_WRITE, d_tracer,
+			tr, &set_tracer_fops);
+
+	trace_create_file("tracing_cpumask", TRACE_MODE_WRITE, d_tracer,
+			  tr, &tracing_cpumask_fops);
+
+	trace_create_file("trace_options", TRACE_MODE_WRITE, d_tracer,
+			  tr, &tracing_iter_fops);
+
+	trace_create_file("trace", TRACE_MODE_WRITE, d_tracer,
+			  tr, &tracing_fops);
+
+	trace_create_file("trace_pipe", TRACE_MODE_READ, d_tracer,
+			  tr, &tracing_pipe_fops);
+
+	trace_create_file("buffer_size_kb", TRACE_MODE_WRITE, d_tracer,
+			  tr, &tracing_entries_fops);
+
+	trace_create_file("buffer_total_size_kb", TRACE_MODE_READ, d_tracer,
+			  tr, &tracing_total_entries_fops);
+
+	trace_create_file("free_buffer", 0200, d_tracer,
+			  tr, &tracing_free_buffer_fops);
+
+	trace_create_file("trace_marker", 0220, d_tracer,
+			  tr, &tracing_mark_fops);
+
+	file = __find_event_file(tr, "ftrace", "print");
+	if (file && file->dir)
+		trace_create_file("trigger", TRACE_MODE_WRITE, file->dir,
+				  file, &event_trigger_fops);
+	tr->trace_marker_file = file;
+
+	trace_create_file("trace_marker_raw", 0220, d_tracer,
+			  tr, &tracing_mark_raw_fops);
+
+	trace_create_file("trace_clock", TRACE_MODE_WRITE, d_tracer, tr,
+			  &trace_clock_fops);
+
+	trace_create_file("tracing_on", TRACE_MODE_WRITE, d_tracer,
+			  tr, &rb_simple_fops);
+
+	trace_create_file("timestamp_mode", TRACE_MODE_READ, d_tracer, tr,
+			  &trace_time_stamp_mode_fops);
+
+	tr->buffer_percent = 50;
+
+	trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer,
+			tr, &buffer_percent_fops);
+
+	create_trace_options_dir(tr);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	trace_create_maxlat_file(tr, d_tracer);
+#endif
+
+	if (ftrace_create_function_files(tr, d_tracer))
+		MEM_FAIL(1, "Could not allocate function filter files");
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+	trace_create_file("snapshot", TRACE_MODE_WRITE, d_tracer,
+			  tr, &snapshot_fops);
+#endif
+
+	trace_create_file("error_log", TRACE_MODE_WRITE, d_tracer,
+			  tr, &tracing_err_log_fops);
+
+	for_each_tracing_cpu(cpu)
+		tracing_init_tracefs_percpu(tr, cpu);
+
+	ftrace_init_tracefs(tr, d_tracer);
+}
+
+static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
+{
+	struct vfsmount *mnt;
+	struct file_system_type *type;
+
+	/*
+	 * To maintain backward compatibility for tools that mount
+	 * debugfs to get to the tracing facility, tracefs is automatically
+	 * mounted to the debugfs/tracing directory.
+	 */
+	type = get_fs_type("tracefs");
+	if (!type)
+		return NULL;
+	mnt = vfs_submount(mntpt, type, "tracefs", NULL);
+	put_filesystem(type);
+	if (IS_ERR(mnt))
+		return NULL;
+	mntget(mnt);
+
+	return mnt;
+}
+
+/**
+ * tracing_init_dentry - initialize top level trace array
+ *
+ * This is called when creating files or directories in the tracing
+ * directory. It is called via fs_initcall() by any of the boot up code
+ * and expects to return the dentry of the top level tracing directory.
+ */
+int tracing_init_dentry(void)
+{
+	struct trace_array *tr = &global_trace;
+
+	if (security_locked_down(LOCKDOWN_TRACEFS)) {
+		pr_warn("Tracing disabled due to lockdown\n");
+		return -EPERM;
+	}
+
+	/* The top level trace array uses  NULL as parent */
+	if (tr->dir)
+		return 0;
+
+	if (WARN_ON(!tracefs_initialized()))
+		return -ENODEV;
+
+	/*
+	 * As there may still be users that expect the tracing
+	 * files to exist in debugfs/tracing, we must automount
+	 * the tracefs file system there, so older tools still
+	 * work with the newer kernel.
+	 */
+	tr->dir = debugfs_create_automount("tracing", NULL,
+					   trace_automount, NULL);
+
+	return 0;
+}
+
+extern struct trace_eval_map *__start_ftrace_eval_maps[];
+extern struct trace_eval_map *__stop_ftrace_eval_maps[];
+
+static struct workqueue_struct *eval_map_wq __initdata;
+static struct work_struct eval_map_work __initdata;
+static struct work_struct tracerfs_init_work __initdata;
+
+static void __init eval_map_work_func(struct work_struct *work)
+{
+	int len;
+
+	len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
+	trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
+}
+
+static int __init trace_eval_init(void)
+{
+	INIT_WORK(&eval_map_work, eval_map_work_func);
+
+	eval_map_wq = alloc_workqueue("eval_map_wq", WQ_UNBOUND, 0);
+	if (!eval_map_wq) {
+		pr_err("Unable to allocate eval_map_wq\n");
+		/* Do work here */
+		eval_map_work_func(&eval_map_work);
+		return -ENOMEM;
+	}
+
+	queue_work(eval_map_wq, &eval_map_work);
+	return 0;
+}
+
+subsys_initcall(trace_eval_init);
+
+static int __init trace_eval_sync(void)
+{
+	/* Make sure the eval map updates are finished */
+	if (eval_map_wq)
+		destroy_workqueue(eval_map_wq);
+	return 0;
+}
+
+late_initcall_sync(trace_eval_sync);
+
+
+#ifdef CONFIG_MODULES
+static void trace_module_add_evals(struct module *mod)
+{
+	if (!mod->num_trace_evals)
+		return;
+
+	/*
+	 * Modules with bad taint do not have events created, do
+	 * not bother with enums either.
+	 */
+	if (trace_module_has_bad_taint(mod))
+		return;
+
+	trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
+}
+
+#ifdef CONFIG_TRACE_EVAL_MAP_FILE
+static void trace_module_remove_evals(struct module *mod)
+{
+	union trace_eval_map_item *map;
+	union trace_eval_map_item **last = &trace_eval_maps;
+
+	if (!mod->num_trace_evals)
+		return;
+
+	mutex_lock(&trace_eval_mutex);
+
+	map = trace_eval_maps;
+
+	while (map) {
+		if (map->head.mod == mod)
+			break;
+		map = trace_eval_jmp_to_tail(map);
+		last = &map->tail.next;
+		map = map->tail.next;
+	}
+	if (!map)
+		goto out;
+
+	*last = trace_eval_jmp_to_tail(map)->tail.next;
+	kfree(map);
+ out:
+	mutex_unlock(&trace_eval_mutex);
+}
+#else
+static inline void trace_module_remove_evals(struct module *mod) { }
+#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
+
+static int trace_module_notify(struct notifier_block *self,
+			       unsigned long val, void *data)
+{
+	struct module *mod = data;
+
+	switch (val) {
+	case MODULE_STATE_COMING:
+		trace_module_add_evals(mod);
+		break;
+	case MODULE_STATE_GOING:
+		trace_module_remove_evals(mod);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block trace_module_nb = {
+	.notifier_call = trace_module_notify,
+	.priority = 0,
+};
+#endif /* CONFIG_MODULES */
+
+static __init void tracer_init_tracefs_work_func(struct work_struct *work)
+{
+
+	event_trace_init();
+
+	init_tracer_tracefs(&global_trace, NULL);
+	ftrace_init_tracefs_toplevel(&global_trace, NULL);
+
+	trace_create_file("tracing_thresh", TRACE_MODE_WRITE, NULL,
+			&global_trace, &tracing_thresh_fops);
+
+	trace_create_file("README", TRACE_MODE_READ, NULL,
+			NULL, &tracing_readme_fops);
+
+	trace_create_file("saved_cmdlines", TRACE_MODE_READ, NULL,
+			NULL, &tracing_saved_cmdlines_fops);
+
+	trace_create_file("saved_cmdlines_size", TRACE_MODE_WRITE, NULL,
+			  NULL, &tracing_saved_cmdlines_size_fops);
+
+	trace_create_file("saved_tgids", TRACE_MODE_READ, NULL,
+			NULL, &tracing_saved_tgids_fops);
+
+	trace_create_eval_file(NULL);
+
+#ifdef CONFIG_MODULES
+	register_module_notifier(&trace_module_nb);
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+	trace_create_file("dyn_ftrace_total_info", TRACE_MODE_READ, NULL,
+			NULL, &tracing_dyn_info_fops);
+#endif
+
+	create_trace_instances(NULL);
+
+	update_tracer_options(&global_trace);
+}
+
+static __init int tracer_init_tracefs(void)
+{
+	int ret;
+
+	trace_access_lock_init();
+
+	ret = tracing_init_dentry();
+	if (ret)
+		return 0;
+
+	if (eval_map_wq) {
+		INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func);
+		queue_work(eval_map_wq, &tracerfs_init_work);
+	} else {
+		tracer_init_tracefs_work_func(NULL);
+	}
+
+	rv_init_interface();
+
+	return 0;
+}
+
+fs_initcall(tracer_init_tracefs);
+
+static int trace_panic_handler(struct notifier_block *this,
+			       unsigned long event, void *unused)
+{
+	if (ftrace_dump_on_oops)
+		ftrace_dump(ftrace_dump_on_oops);
+	return NOTIFY_OK;
+}
+
+static struct notifier_block trace_panic_notifier = {
+	.notifier_call  = trace_panic_handler,
+	.next           = NULL,
+	.priority       = 150   /* priority: INT_MAX >= x >= 0 */
+};
+
+static int trace_die_handler(struct notifier_block *self,
+			     unsigned long val,
+			     void *data)
+{
+	switch (val) {
+	case DIE_OOPS:
+		if (ftrace_dump_on_oops)
+			ftrace_dump(ftrace_dump_on_oops);
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block trace_die_notifier = {
+	.notifier_call = trace_die_handler,
+	.priority = 200
+};
+
+/*
+ * printk is set to max of 1024, we really don't need it that big.
+ * Nothing should be printing 1000 characters anyway.
+ */
+#define TRACE_MAX_PRINT		1000
+
+/*
+ * Define here KERN_TRACE so that we have one place to modify
+ * it if we decide to change what log level the ftrace dump
+ * should be at.
+ */
+#define KERN_TRACE		KERN_EMERG
+
+void
+trace_printk_seq(struct trace_seq *s)
+{
+	/* Probably should print a warning here. */
+	if (s->seq.len >= TRACE_MAX_PRINT)
+		s->seq.len = TRACE_MAX_PRINT;
+
+	/*
+	 * More paranoid code. Although the buffer size is set to
+	 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
+	 * an extra layer of protection.
+	 */
+	if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
+		s->seq.len = s->seq.size - 1;
+
+	/* should be zero ended, but we are paranoid. */
+	s->buffer[s->seq.len] = 0;
+
+	printk(KERN_TRACE "%s", s->buffer);
+
+	trace_seq_init(s);
+}
+
+void trace_init_global_iter(struct trace_iterator *iter)
+{
+	iter->tr = &global_trace;
+	iter->trace = iter->tr->current_trace;
+	iter->cpu_file = RING_BUFFER_ALL_CPUS;
+	iter->array_buffer = &global_trace.array_buffer;
+
+	if (iter->trace && iter->trace->open)
+		iter->trace->open(iter);
+
+	/* Annotate start of buffers if we had overruns */
+	if (ring_buffer_overruns(iter->array_buffer->buffer))
+		iter->iter_flags |= TRACE_FILE_ANNOTATE;
+
+	/* Output in nanoseconds only if we are using a clock in nanoseconds. */
+	if (trace_clocks[iter->tr->clock_id].in_ns)
+		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
+
+	/* Can not use kmalloc for iter.temp and iter.fmt */
+	iter->temp = static_temp_buf;
+	iter->temp_size = STATIC_TEMP_BUF_SIZE;
+	iter->fmt = static_fmt_buf;
+	iter->fmt_size = STATIC_FMT_BUF_SIZE;
+}
+
+void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
+{
+	/* use static because iter can be a bit big for the stack */
+	static struct trace_iterator iter;
+	static atomic_t dump_running;
+	struct trace_array *tr = &global_trace;
+	unsigned int old_userobj;
+	unsigned long flags;
+	int cnt = 0, cpu;
+
+	/* Only allow one dump user at a time. */
+	if (atomic_inc_return(&dump_running) != 1) {
+		atomic_dec(&dump_running);
+		return;
+	}
+
+	/*
+	 * Always turn off tracing when we dump.
+	 * We don't need to show trace output of what happens
+	 * between multiple crashes.
+	 *
+	 * If the user does a sysrq-z, then they can re-enable
+	 * tracing with echo 1 > tracing_on.
+	 */
+	tracing_off();
+
+	local_irq_save(flags);
+
+	/* Simulate the iterator */
+	trace_init_global_iter(&iter);
+
+	for_each_tracing_cpu(cpu) {
+		atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
+	}
+
+	old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
+
+	/* don't look at user memory in panic mode */
+	tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
+
+	switch (oops_dump_mode) {
+	case DUMP_ALL:
+		iter.cpu_file = RING_BUFFER_ALL_CPUS;
+		break;
+	case DUMP_ORIG:
+		iter.cpu_file = raw_smp_processor_id();
+		break;
+	case DUMP_NONE:
+		goto out_enable;
+	default:
+		printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
+		iter.cpu_file = RING_BUFFER_ALL_CPUS;
+	}
+
+	printk(KERN_TRACE "Dumping ftrace buffer:\n");
+
+	/* Did function tracer already get disabled? */
+	if (ftrace_is_dead()) {
+		printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
+		printk("#          MAY BE MISSING FUNCTION EVENTS\n");
+	}
+
+	/*
+	 * We need to stop all tracing on all CPUS to read
+	 * the next buffer. This is a bit expensive, but is
+	 * not done often. We fill all what we can read,
+	 * and then release the locks again.
+	 */
+
+	while (!trace_empty(&iter)) {
+
+		if (!cnt)
+			printk(KERN_TRACE "---------------------------------\n");
+
+		cnt++;
+
+		trace_iterator_reset(&iter);
+		iter.iter_flags |= TRACE_FILE_LAT_FMT;
+
+		if (trace_find_next_entry_inc(&iter) != NULL) {
+			int ret;
+
+			ret = print_trace_line(&iter);
+			if (ret != TRACE_TYPE_NO_CONSUME)
+				trace_consume(&iter);
+		}
+		touch_nmi_watchdog();
+
+		trace_printk_seq(&iter.seq);
+	}
+
+	if (!cnt)
+		printk(KERN_TRACE "   (ftrace buffer empty)\n");
+	else
+		printk(KERN_TRACE "---------------------------------\n");
+
+ out_enable:
+	tr->trace_flags |= old_userobj;
+
+	for_each_tracing_cpu(cpu) {
+		atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
+	}
+	atomic_dec(&dump_running);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(ftrace_dump);
+
+#define WRITE_BUFSIZE  4096
+
+ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
+				size_t count, loff_t *ppos,
+				int (*createfn)(const char *))
+{
+	char *kbuf, *buf, *tmp;
+	int ret = 0;
+	size_t done = 0;
+	size_t size;
+
+	kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
+	if (!kbuf)
+		return -ENOMEM;
+
+	while (done < count) {
+		size = count - done;
+
+		if (size >= WRITE_BUFSIZE)
+			size = WRITE_BUFSIZE - 1;
+
+		if (copy_from_user(kbuf, buffer + done, size)) {
+			ret = -EFAULT;
+			goto out;
+		}
+		kbuf[size] = '\0';
+		buf = kbuf;
+		do {
+			tmp = strchr(buf, '\n');
+			if (tmp) {
+				*tmp = '\0';
+				size = tmp - buf + 1;
+			} else {
+				size = strlen(buf);
+				if (done + size < count) {
+					if (buf != kbuf)
+						break;
+					/* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
+					pr_warn("Line length is too long: Should be less than %d\n",
+						WRITE_BUFSIZE - 2);
+					ret = -EINVAL;
+					goto out;
+				}
+			}
+			done += size;
+
+			/* Remove comments */
+			tmp = strchr(buf, '#');
+
+			if (tmp)
+				*tmp = '\0';
+
+			ret = createfn(buf);
+			if (ret)
+				goto out;
+			buf += size;
+
+		} while (done < count);
+	}
+	ret = done;
+
+out:
+	kfree(kbuf);
+
+	return ret;
+}
+
+__init static int tracer_alloc_buffers(void)
+{
+	int ring_buf_size;
+	int ret = -ENOMEM;
+
+
+	if (security_locked_down(LOCKDOWN_TRACEFS)) {
+		pr_warn("Tracing disabled due to lockdown\n");
+		return -EPERM;
+	}
+
+	/*
+	 * Make sure we don't accidentally add more trace options
+	 * than we have bits for.
+	 */
+	BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
+
+	if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
+		goto out;
+
+	if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
+		goto out_free_buffer_mask;
+
+	/* Only allocate trace_printk buffers if a trace_printk exists */
+	if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
+		/* Must be called before global_trace.buffer is allocated */
+		trace_printk_init_buffers();
+
+	/* To save memory, keep the ring buffer size to its minimum */
+	if (ring_buffer_expanded)
+		ring_buf_size = trace_buf_size;
+	else
+		ring_buf_size = 1;
+
+	cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
+	cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
+
+	raw_spin_lock_init(&global_trace.start_lock);
+
+	/*
+	 * The prepare callbacks allocates some memory for the ring buffer. We
+	 * don't free the buffer if the CPU goes down. If we were to free
+	 * the buffer, then the user would lose any trace that was in the
+	 * buffer. The memory will be removed once the "instance" is removed.
+	 */
+	ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
+				      "trace/RB:prepare", trace_rb_cpu_prepare,
+				      NULL);
+	if (ret < 0)
+		goto out_free_cpumask;
+	/* Used for event triggers */
+	ret = -ENOMEM;
+	temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
+	if (!temp_buffer)
+		goto out_rm_hp_state;
+
+	if (trace_create_savedcmd() < 0)
+		goto out_free_temp_buffer;
+
+	if (!zalloc_cpumask_var(&global_trace.pipe_cpumask, GFP_KERNEL))
+		goto out_free_savedcmd;
+
+	/* TODO: make the number of buffers hot pluggable with CPUS */
+	if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
+		MEM_FAIL(1, "tracer: failed to allocate ring buffer!\n");
+		goto out_free_pipe_cpumask;
+	}
+	if (global_trace.buffer_disabled)
+		tracing_off();
+
+	if (trace_boot_clock) {
+		ret = tracing_set_clock(&global_trace, trace_boot_clock);
+		if (ret < 0)
+			pr_warn("Trace clock %s not defined, going back to default\n",
+				trace_boot_clock);
+	}
+
+	/*
+	 * register_tracer() might reference current_trace, so it
+	 * needs to be set before we register anything. This is
+	 * just a bootstrap of current_trace anyway.
+	 */
+	global_trace.current_trace = &nop_trace;
+
+	global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+
+	ftrace_init_global_array_ops(&global_trace);
+
+	init_trace_flags_index(&global_trace);
+
+	register_tracer(&nop_trace);
+
+	/* Function tracing may start here (via kernel command line) */
+	init_function_trace();
+
+	/* All seems OK, enable tracing */
+	tracing_disabled = 0;
+
+	atomic_notifier_chain_register(&panic_notifier_list,
+				       &trace_panic_notifier);
+
+	register_die_notifier(&trace_die_notifier);
+
+	global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
+
+	INIT_LIST_HEAD(&global_trace.systems);
+	INIT_LIST_HEAD(&global_trace.events);
+	INIT_LIST_HEAD(&global_trace.hist_vars);
+	INIT_LIST_HEAD(&global_trace.err_log);
+	list_add(&global_trace.list, &ftrace_trace_arrays);
+
+	apply_trace_boot_options();
+
+	register_snapshot_cmd();
+
+	test_can_verify();
+
+	return 0;
+
+out_free_pipe_cpumask:
+	free_cpumask_var(global_trace.pipe_cpumask);
+out_free_savedcmd:
+	free_saved_cmdlines_buffer(savedcmd);
+out_free_temp_buffer:
+	ring_buffer_free(temp_buffer);
+out_rm_hp_state:
+	cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
+out_free_cpumask:
+	free_cpumask_var(global_trace.tracing_cpumask);
+out_free_buffer_mask:
+	free_cpumask_var(tracing_buffer_mask);
+out:
+	return ret;
+}
+
+void __init ftrace_boot_snapshot(void)
+{
+	if (snapshot_at_boot) {
+		tracing_snapshot();
+		internal_trace_puts("** Boot snapshot taken **\n");
+	}
+}
+
+void __init early_trace_init(void)
+{
+	if (tracepoint_printk) {
+		tracepoint_print_iter =
+			kzalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
+		if (MEM_FAIL(!tracepoint_print_iter,
+			     "Failed to allocate trace iterator\n"))
+			tracepoint_printk = 0;
+		else
+			static_key_enable(&tracepoint_printk_key.key);
+	}
+	tracer_alloc_buffers();
+
+	init_events();
+}
+
+void __init trace_init(void)
+{
+	trace_event_init();
+}
+
+__init static void clear_boot_tracer(void)
+{
+	/*
+	 * The default tracer at boot buffer is an init section.
+	 * This function is called in lateinit. If we did not
+	 * find the boot tracer, then clear it out, to prevent
+	 * later registration from accessing the buffer that is
+	 * about to be freed.
+	 */
+	if (!default_bootup_tracer)
+		return;
+
+	printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
+	       default_bootup_tracer);
+	default_bootup_tracer = NULL;
+}
+
+#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
+__init static void tracing_set_default_clock(void)
+{
+	/* sched_clock_stable() is determined in late_initcall */
+	if (!trace_boot_clock && !sched_clock_stable()) {
+		if (security_locked_down(LOCKDOWN_TRACEFS)) {
+			pr_warn("Can not set tracing clock due to lockdown\n");
+			return;
+		}
+
+		printk(KERN_WARNING
+		       "Unstable clock detected, switching default tracing clock to \"global\"\n"
+		       "If you want to keep using the local clock, then add:\n"
+		       "  \"trace_clock=local\"\n"
+		       "on the kernel command line\n");
+		tracing_set_clock(&global_trace, "global");
+	}
+}
+#else
+static inline void tracing_set_default_clock(void) { }
+#endif
+
+__init static int late_trace_init(void)
+{
+	if (tracepoint_printk && tracepoint_printk_stop_on_boot) {
+		static_key_disable(&tracepoint_printk_key.key);
+		tracepoint_printk = 0;
+	}
+
+	tracing_set_default_clock();
+	clear_boot_tracer();
+	return 0;
+}
+
+late_initcall_sync(late_trace_init);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
new file mode 100644
index 000000000..aad7fcd84
--- /dev/null
+++ b/kernel/trace/trace.h
@@ -0,0 +1,2032 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#ifndef _LINUX_KERNEL_TRACE_H
+#define _LINUX_KERNEL_TRACE_H
+
+#include <linux/fs.h>
+#include <linux/atomic.h>
+#include <linux/sched.h>
+#include <linux/clocksource.h>
+#include <linux/ring_buffer.h>
+#include <linux/mmiotrace.h>
+#include <linux/tracepoint.h>
+#include <linux/ftrace.h>
+#include <linux/trace.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/trace_seq.h>
+#include <linux/trace_events.h>
+#include <linux/compiler.h>
+#include <linux/glob.h>
+#include <linux/irq_work.h>
+#include <linux/workqueue.h>
+#include <linux/ctype.h>
+#include <linux/once_lite.h>
+
+#include "pid_list.h"
+
+#ifdef CONFIG_FTRACE_SYSCALLS
+#include <asm/unistd.h>		/* For NR_SYSCALLS	     */
+#include <asm/syscall.h>	/* some archs define it here */
+#endif
+
+#define TRACE_MODE_WRITE	0640
+#define TRACE_MODE_READ		0440
+
+enum trace_type {
+	__TRACE_FIRST_TYPE = 0,
+
+	TRACE_FN,
+	TRACE_CTX,
+	TRACE_WAKE,
+	TRACE_STACK,
+	TRACE_PRINT,
+	TRACE_BPRINT,
+	TRACE_MMIO_RW,
+	TRACE_MMIO_MAP,
+	TRACE_BRANCH,
+	TRACE_GRAPH_RET,
+	TRACE_GRAPH_ENT,
+	TRACE_USER_STACK,
+	TRACE_BLK,
+	TRACE_BPUTS,
+	TRACE_HWLAT,
+	TRACE_OSNOISE,
+	TRACE_TIMERLAT,
+	TRACE_RAW_DATA,
+	TRACE_FUNC_REPEATS,
+
+	__TRACE_LAST_TYPE,
+};
+
+
+#undef __field
+#define __field(type, item)		type	item;
+
+#undef __field_fn
+#define __field_fn(type, item)		type	item;
+
+#undef __field_struct
+#define __field_struct(type, item)	__field(type, item)
+
+#undef __field_desc
+#define __field_desc(type, container, item)
+
+#undef __field_packed
+#define __field_packed(type, container, item)
+
+#undef __array
+#define __array(type, item, size)	type	item[size];
+
+#undef __array_desc
+#define __array_desc(type, container, item, size)
+
+#undef __dynamic_array
+#define __dynamic_array(type, item)	type	item[];
+
+#undef __rel_dynamic_array
+#define __rel_dynamic_array(type, item)	type	item[];
+
+#undef F_STRUCT
+#define F_STRUCT(args...)		args
+
+#undef FTRACE_ENTRY
+#define FTRACE_ENTRY(name, struct_name, id, tstruct, print)		\
+	struct struct_name {						\
+		struct trace_entry	ent;				\
+		tstruct							\
+	}
+
+#undef FTRACE_ENTRY_DUP
+#define FTRACE_ENTRY_DUP(name, name_struct, id, tstruct, printk)
+
+#undef FTRACE_ENTRY_REG
+#define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print,	regfn)	\
+	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
+
+#undef FTRACE_ENTRY_PACKED
+#define FTRACE_ENTRY_PACKED(name, struct_name, id, tstruct, print)	\
+	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print)) __packed
+
+#include "trace_entries.h"
+
+/* Use this for memory failure errors */
+#define MEM_FAIL(condition, fmt, ...)					\
+	DO_ONCE_LITE_IF(condition, pr_err, "ERROR: " fmt, ##__VA_ARGS__)
+
+#define FAULT_STRING "(fault)"
+
+#define HIST_STACKTRACE_DEPTH	16
+#define HIST_STACKTRACE_SIZE	(HIST_STACKTRACE_DEPTH * sizeof(unsigned long))
+#define HIST_STACKTRACE_SKIP	5
+
+/*
+ * syscalls are special, and need special handling, this is why
+ * they are not included in trace_entries.h
+ */
+struct syscall_trace_enter {
+	struct trace_entry	ent;
+	int			nr;
+	unsigned long		args[];
+};
+
+struct syscall_trace_exit {
+	struct trace_entry	ent;
+	int			nr;
+	long			ret;
+};
+
+struct kprobe_trace_entry_head {
+	struct trace_entry	ent;
+	unsigned long		ip;
+};
+
+struct eprobe_trace_entry_head {
+	struct trace_entry	ent;
+};
+
+struct kretprobe_trace_entry_head {
+	struct trace_entry	ent;
+	unsigned long		func;
+	unsigned long		ret_ip;
+};
+
+#define TRACE_BUF_SIZE		1024
+
+struct trace_array;
+
+/*
+ * The CPU trace array - it consists of thousands of trace entries
+ * plus some other descriptor data: (for example which task started
+ * the trace, etc.)
+ */
+struct trace_array_cpu {
+	atomic_t		disabled;
+	void			*buffer_page;	/* ring buffer spare */
+
+	unsigned long		entries;
+	unsigned long		saved_latency;
+	unsigned long		critical_start;
+	unsigned long		critical_end;
+	unsigned long		critical_sequence;
+	unsigned long		nice;
+	unsigned long		policy;
+	unsigned long		rt_priority;
+	unsigned long		skipped_entries;
+	u64			preempt_timestamp;
+	pid_t			pid;
+	kuid_t			uid;
+	char			comm[TASK_COMM_LEN];
+
+#ifdef CONFIG_FUNCTION_TRACER
+	int			ftrace_ignore_pid;
+#endif
+	bool			ignore_pid;
+};
+
+struct tracer;
+struct trace_option_dentry;
+
+struct array_buffer {
+	struct trace_array		*tr;
+	struct trace_buffer		*buffer;
+	struct trace_array_cpu __percpu	*data;
+	u64				time_start;
+	int				cpu;
+};
+
+#define TRACE_FLAGS_MAX_SIZE		32
+
+struct trace_options {
+	struct tracer			*tracer;
+	struct trace_option_dentry	*topts;
+};
+
+struct trace_pid_list *trace_pid_list_alloc(void);
+void trace_pid_list_free(struct trace_pid_list *pid_list);
+bool trace_pid_list_is_set(struct trace_pid_list *pid_list, unsigned int pid);
+int trace_pid_list_set(struct trace_pid_list *pid_list, unsigned int pid);
+int trace_pid_list_clear(struct trace_pid_list *pid_list, unsigned int pid);
+int trace_pid_list_first(struct trace_pid_list *pid_list, unsigned int *pid);
+int trace_pid_list_next(struct trace_pid_list *pid_list, unsigned int pid,
+			unsigned int *next);
+
+enum {
+	TRACE_PIDS		= BIT(0),
+	TRACE_NO_PIDS		= BIT(1),
+};
+
+static inline bool pid_type_enabled(int type, struct trace_pid_list *pid_list,
+				    struct trace_pid_list *no_pid_list)
+{
+	/* Return true if the pid list in type has pids */
+	return ((type & TRACE_PIDS) && pid_list) ||
+		((type & TRACE_NO_PIDS) && no_pid_list);
+}
+
+static inline bool still_need_pid_events(int type, struct trace_pid_list *pid_list,
+					 struct trace_pid_list *no_pid_list)
+{
+	/*
+	 * Turning off what is in @type, return true if the "other"
+	 * pid list, still has pids in it.
+	 */
+	return (!(type & TRACE_PIDS) && pid_list) ||
+		(!(type & TRACE_NO_PIDS) && no_pid_list);
+}
+
+typedef bool (*cond_update_fn_t)(struct trace_array *tr, void *cond_data);
+
+/**
+ * struct cond_snapshot - conditional snapshot data and callback
+ *
+ * The cond_snapshot structure encapsulates a callback function and
+ * data associated with the snapshot for a given tracing instance.
+ *
+ * When a snapshot is taken conditionally, by invoking
+ * tracing_snapshot_cond(tr, cond_data), the cond_data passed in is
+ * passed in turn to the cond_snapshot.update() function.  That data
+ * can be compared by the update() implementation with the cond_data
+ * contained within the struct cond_snapshot instance associated with
+ * the trace_array.  Because the tr->max_lock is held throughout the
+ * update() call, the update() function can directly retrieve the
+ * cond_snapshot and cond_data associated with the per-instance
+ * snapshot associated with the trace_array.
+ *
+ * The cond_snapshot.update() implementation can save data to be
+ * associated with the snapshot if it decides to, and returns 'true'
+ * in that case, or it returns 'false' if the conditional snapshot
+ * shouldn't be taken.
+ *
+ * The cond_snapshot instance is created and associated with the
+ * user-defined cond_data by tracing_cond_snapshot_enable().
+ * Likewise, the cond_snapshot instance is destroyed and is no longer
+ * associated with the trace instance by
+ * tracing_cond_snapshot_disable().
+ *
+ * The method below is required.
+ *
+ * @update: When a conditional snapshot is invoked, the update()
+ *	callback function is invoked with the tr->max_lock held.  The
+ *	update() implementation signals whether or not to actually
+ *	take the snapshot, by returning 'true' if so, 'false' if no
+ *	snapshot should be taken.  Because the max_lock is held for
+ *	the duration of update(), the implementation is safe to
+ *	directly retrieved and save any implementation data it needs
+ *	to in association with the snapshot.
+ */
+struct cond_snapshot {
+	void				*cond_data;
+	cond_update_fn_t		update;
+};
+
+/*
+ * struct trace_func_repeats - used to keep track of the consecutive
+ * (on the same CPU) calls of a single function.
+ */
+struct trace_func_repeats {
+	unsigned long	ip;
+	unsigned long	parent_ip;
+	unsigned long	count;
+	u64		ts_last_call;
+};
+
+/*
+ * The trace array - an array of per-CPU trace arrays. This is the
+ * highest level data structure that individual tracers deal with.
+ * They have on/off state as well:
+ */
+struct trace_array {
+	struct list_head	list;
+	char			*name;
+	struct array_buffer	array_buffer;
+#ifdef CONFIG_TRACER_MAX_TRACE
+	/*
+	 * The max_buffer is used to snapshot the trace when a maximum
+	 * latency is reached, or when the user initiates a snapshot.
+	 * Some tracers will use this to store a maximum trace while
+	 * it continues examining live traces.
+	 *
+	 * The buffers for the max_buffer are set up the same as the array_buffer
+	 * When a snapshot is taken, the buffer of the max_buffer is swapped
+	 * with the buffer of the array_buffer and the buffers are reset for
+	 * the array_buffer so the tracing can continue.
+	 */
+	struct array_buffer	max_buffer;
+	bool			allocated_snapshot;
+#endif
+#ifdef CONFIG_TRACER_MAX_TRACE
+	unsigned long		max_latency;
+#ifdef CONFIG_FSNOTIFY
+	struct dentry		*d_max_latency;
+	struct work_struct	fsnotify_work;
+	struct irq_work		fsnotify_irqwork;
+#endif
+#endif
+	struct trace_pid_list	__rcu *filtered_pids;
+	struct trace_pid_list	__rcu *filtered_no_pids;
+	/*
+	 * max_lock is used to protect the swapping of buffers
+	 * when taking a max snapshot. The buffers themselves are
+	 * protected by per_cpu spinlocks. But the action of the swap
+	 * needs its own lock.
+	 *
+	 * This is defined as a arch_spinlock_t in order to help
+	 * with performance when lockdep debugging is enabled.
+	 *
+	 * It is also used in other places outside the update_max_tr
+	 * so it needs to be defined outside of the
+	 * CONFIG_TRACER_MAX_TRACE.
+	 */
+	arch_spinlock_t		max_lock;
+	int			buffer_disabled;
+#ifdef CONFIG_FTRACE_SYSCALLS
+	int			sys_refcount_enter;
+	int			sys_refcount_exit;
+	struct trace_event_file __rcu *enter_syscall_files[NR_syscalls];
+	struct trace_event_file __rcu *exit_syscall_files[NR_syscalls];
+#endif
+	int			stop_count;
+	int			clock_id;
+	int			nr_topts;
+	bool			clear_trace;
+	int			buffer_percent;
+	unsigned int		n_err_log_entries;
+	struct tracer		*current_trace;
+	unsigned int		trace_flags;
+	unsigned char		trace_flags_index[TRACE_FLAGS_MAX_SIZE];
+	unsigned int		flags;
+	raw_spinlock_t		start_lock;
+	struct list_head	err_log;
+	struct dentry		*dir;
+	struct dentry		*options;
+	struct dentry		*percpu_dir;
+	struct dentry		*event_dir;
+	struct trace_options	*topts;
+	struct list_head	systems;
+	struct list_head	events;
+	struct trace_event_file *trace_marker_file;
+	cpumask_var_t		tracing_cpumask; /* only trace on set CPUs */
+	/* one per_cpu trace_pipe can be opened by only one user */
+	cpumask_var_t		pipe_cpumask;
+	int			ref;
+	int			trace_ref;
+#ifdef CONFIG_FUNCTION_TRACER
+	struct ftrace_ops	*ops;
+	struct trace_pid_list	__rcu *function_pids;
+	struct trace_pid_list	__rcu *function_no_pids;
+#ifdef CONFIG_DYNAMIC_FTRACE
+	/* All of these are protected by the ftrace_lock */
+	struct list_head	func_probes;
+	struct list_head	mod_trace;
+	struct list_head	mod_notrace;
+#endif
+	/* function tracing enabled */
+	int			function_enabled;
+#endif
+	int			no_filter_buffering_ref;
+	struct list_head	hist_vars;
+#ifdef CONFIG_TRACER_SNAPSHOT
+	struct cond_snapshot	*cond_snapshot;
+#endif
+	struct trace_func_repeats	__percpu *last_func_repeats;
+};
+
+enum {
+	TRACE_ARRAY_FL_GLOBAL	= (1 << 0)
+};
+
+extern struct list_head ftrace_trace_arrays;
+
+extern struct mutex trace_types_lock;
+
+extern int trace_array_get(struct trace_array *tr);
+extern int tracing_check_open_get_tr(struct trace_array *tr);
+extern struct trace_array *trace_array_find(const char *instance);
+extern struct trace_array *trace_array_find_get(const char *instance);
+
+extern u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe);
+extern int tracing_set_filter_buffering(struct trace_array *tr, bool set);
+extern int tracing_set_clock(struct trace_array *tr, const char *clockstr);
+
+extern bool trace_clock_in_ns(struct trace_array *tr);
+
+/*
+ * The global tracer (top) should be the first trace array added,
+ * but we check the flag anyway.
+ */
+static inline struct trace_array *top_trace_array(void)
+{
+	struct trace_array *tr;
+
+	if (list_empty(&ftrace_trace_arrays))
+		return NULL;
+
+	tr = list_entry(ftrace_trace_arrays.prev,
+			typeof(*tr), list);
+	WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
+	return tr;
+}
+
+#define FTRACE_CMP_TYPE(var, type) \
+	__builtin_types_compatible_p(typeof(var), type *)
+
+#undef IF_ASSIGN
+#define IF_ASSIGN(var, entry, etype, id)			\
+	if (FTRACE_CMP_TYPE(var, etype)) {			\
+		var = (typeof(var))(entry);			\
+		WARN_ON(id != 0 && (entry)->type != id);	\
+		break;						\
+	}
+
+/* Will cause compile errors if type is not found. */
+extern void __ftrace_bad_type(void);
+
+/*
+ * The trace_assign_type is a verifier that the entry type is
+ * the same as the type being assigned. To add new types simply
+ * add a line with the following format:
+ *
+ * IF_ASSIGN(var, ent, type, id);
+ *
+ *  Where "type" is the trace type that includes the trace_entry
+ *  as the "ent" item. And "id" is the trace identifier that is
+ *  used in the trace_type enum.
+ *
+ *  If the type can have more than one id, then use zero.
+ */
+#define trace_assign_type(var, ent)					\
+	do {								\
+		IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);	\
+		IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);	\
+		IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);	\
+		IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
+		IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);	\
+		IF_ASSIGN(var, ent, struct bprint_entry, TRACE_BPRINT);	\
+		IF_ASSIGN(var, ent, struct bputs_entry, TRACE_BPUTS);	\
+		IF_ASSIGN(var, ent, struct hwlat_entry, TRACE_HWLAT);	\
+		IF_ASSIGN(var, ent, struct osnoise_entry, TRACE_OSNOISE);\
+		IF_ASSIGN(var, ent, struct timerlat_entry, TRACE_TIMERLAT);\
+		IF_ASSIGN(var, ent, struct raw_data_entry, TRACE_RAW_DATA);\
+		IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,		\
+			  TRACE_MMIO_RW);				\
+		IF_ASSIGN(var, ent, struct trace_mmiotrace_map,		\
+			  TRACE_MMIO_MAP);				\
+		IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \
+		IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry,	\
+			  TRACE_GRAPH_ENT);		\
+		IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,	\
+			  TRACE_GRAPH_RET);		\
+		IF_ASSIGN(var, ent, struct func_repeats_entry,		\
+			  TRACE_FUNC_REPEATS);				\
+		__ftrace_bad_type();					\
+	} while (0)
+
+/*
+ * An option specific to a tracer. This is a boolean value.
+ * The bit is the bit index that sets its value on the
+ * flags value in struct tracer_flags.
+ */
+struct tracer_opt {
+	const char	*name; /* Will appear on the trace_options file */
+	u32		bit; /* Mask assigned in val field in tracer_flags */
+};
+
+/*
+ * The set of specific options for a tracer. Your tracer
+ * have to set the initial value of the flags val.
+ */
+struct tracer_flags {
+	u32			val;
+	struct tracer_opt	*opts;
+	struct tracer		*trace;
+};
+
+/* Makes more easy to define a tracer opt */
+#define TRACER_OPT(s, b)	.name = #s, .bit = b
+
+
+struct trace_option_dentry {
+	struct tracer_opt		*opt;
+	struct tracer_flags		*flags;
+	struct trace_array		*tr;
+	struct dentry			*entry;
+};
+
+/**
+ * struct tracer - a specific tracer and its callbacks to interact with tracefs
+ * @name: the name chosen to select it on the available_tracers file
+ * @init: called when one switches to this tracer (echo name > current_tracer)
+ * @reset: called when one switches to another tracer
+ * @start: called when tracing is unpaused (echo 1 > tracing_on)
+ * @stop: called when tracing is paused (echo 0 > tracing_on)
+ * @update_thresh: called when tracing_thresh is updated
+ * @open: called when the trace file is opened
+ * @pipe_open: called when the trace_pipe file is opened
+ * @close: called when the trace file is released
+ * @pipe_close: called when the trace_pipe file is released
+ * @read: override the default read callback on trace_pipe
+ * @splice_read: override the default splice_read callback on trace_pipe
+ * @selftest: selftest to run on boot (see trace_selftest.c)
+ * @print_headers: override the first lines that describe your columns
+ * @print_line: callback that prints a trace
+ * @set_flag: signals one of your private flags changed (trace_options file)
+ * @flags: your private flags
+ */
+struct tracer {
+	const char		*name;
+	int			(*init)(struct trace_array *tr);
+	void			(*reset)(struct trace_array *tr);
+	void			(*start)(struct trace_array *tr);
+	void			(*stop)(struct trace_array *tr);
+	int			(*update_thresh)(struct trace_array *tr);
+	void			(*open)(struct trace_iterator *iter);
+	void			(*pipe_open)(struct trace_iterator *iter);
+	void			(*close)(struct trace_iterator *iter);
+	void			(*pipe_close)(struct trace_iterator *iter);
+	ssize_t			(*read)(struct trace_iterator *iter,
+					struct file *filp, char __user *ubuf,
+					size_t cnt, loff_t *ppos);
+	ssize_t			(*splice_read)(struct trace_iterator *iter,
+					       struct file *filp,
+					       loff_t *ppos,
+					       struct pipe_inode_info *pipe,
+					       size_t len,
+					       unsigned int flags);
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+	int			(*selftest)(struct tracer *trace,
+					    struct trace_array *tr);
+#endif
+	void			(*print_header)(struct seq_file *m);
+	enum print_line_t	(*print_line)(struct trace_iterator *iter);
+	/* If you handled the flag setting, return 0 */
+	int			(*set_flag)(struct trace_array *tr,
+					    u32 old_flags, u32 bit, int set);
+	/* Return 0 if OK with change, else return non-zero */
+	int			(*flag_changed)(struct trace_array *tr,
+						u32 mask, int set);
+	struct tracer		*next;
+	struct tracer_flags	*flags;
+	int			enabled;
+	bool			print_max;
+	bool			allow_instances;
+#ifdef CONFIG_TRACER_MAX_TRACE
+	bool			use_max_tr;
+#endif
+	/* True if tracer cannot be enabled in kernel param */
+	bool			noboot;
+};
+
+static inline struct ring_buffer_iter *
+trace_buffer_iter(struct trace_iterator *iter, int cpu)
+{
+	return iter->buffer_iter ? iter->buffer_iter[cpu] : NULL;
+}
+
+int tracer_init(struct tracer *t, struct trace_array *tr);
+int tracing_is_enabled(void);
+void tracing_reset_online_cpus(struct array_buffer *buf);
+void tracing_reset_current(int cpu);
+void tracing_reset_all_online_cpus(void);
+void tracing_reset_all_online_cpus_unlocked(void);
+int tracing_open_generic(struct inode *inode, struct file *filp);
+int tracing_open_generic_tr(struct inode *inode, struct file *filp);
+int tracing_open_file_tr(struct inode *inode, struct file *filp);
+int tracing_release_file_tr(struct inode *inode, struct file *filp);
+int tracing_single_release_file_tr(struct inode *inode, struct file *filp);
+bool tracing_is_disabled(void);
+bool tracer_tracing_is_on(struct trace_array *tr);
+void tracer_tracing_on(struct trace_array *tr);
+void tracer_tracing_off(struct trace_array *tr);
+struct dentry *trace_create_file(const char *name,
+				 umode_t mode,
+				 struct dentry *parent,
+				 void *data,
+				 const struct file_operations *fops);
+
+int tracing_init_dentry(void);
+
+struct ring_buffer_event;
+
+struct ring_buffer_event *
+trace_buffer_lock_reserve(struct trace_buffer *buffer,
+			  int type,
+			  unsigned long len,
+			  unsigned int trace_ctx);
+
+struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
+						struct trace_array_cpu *data);
+
+struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
+					  int *ent_cpu, u64 *ent_ts);
+
+void trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
+					struct ring_buffer_event *event);
+
+bool trace_is_tracepoint_string(const char *str);
+const char *trace_event_format(struct trace_iterator *iter, const char *fmt);
+void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
+			 va_list ap);
+
+int trace_empty(struct trace_iterator *iter);
+
+void *trace_find_next_entry_inc(struct trace_iterator *iter);
+
+void trace_init_global_iter(struct trace_iterator *iter);
+
+void tracing_iter_reset(struct trace_iterator *iter, int cpu);
+
+unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu);
+unsigned long trace_total_entries(struct trace_array *tr);
+
+void trace_function(struct trace_array *tr,
+		    unsigned long ip,
+		    unsigned long parent_ip,
+		    unsigned int trace_ctx);
+void trace_graph_function(struct trace_array *tr,
+		    unsigned long ip,
+		    unsigned long parent_ip,
+		    unsigned int trace_ctx);
+void trace_latency_header(struct seq_file *m);
+void trace_default_header(struct seq_file *m);
+void print_trace_header(struct seq_file *m, struct trace_iterator *iter);
+
+void trace_graph_return(struct ftrace_graph_ret *trace);
+int trace_graph_entry(struct ftrace_graph_ent *trace);
+void set_graph_array(struct trace_array *tr);
+
+void tracing_start_cmdline_record(void);
+void tracing_stop_cmdline_record(void);
+void tracing_start_tgid_record(void);
+void tracing_stop_tgid_record(void);
+
+int register_tracer(struct tracer *type);
+int is_tracing_stopped(void);
+
+loff_t tracing_lseek(struct file *file, loff_t offset, int whence);
+
+extern cpumask_var_t __read_mostly tracing_buffer_mask;
+
+#define for_each_tracing_cpu(cpu)	\
+	for_each_cpu(cpu, tracing_buffer_mask)
+
+extern unsigned long nsecs_to_usecs(unsigned long nsecs);
+
+extern unsigned long tracing_thresh;
+
+/* PID filtering */
+
+extern int pid_max;
+
+bool trace_find_filtered_pid(struct trace_pid_list *filtered_pids,
+			     pid_t search_pid);
+bool trace_ignore_this_task(struct trace_pid_list *filtered_pids,
+			    struct trace_pid_list *filtered_no_pids,
+			    struct task_struct *task);
+void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
+				  struct task_struct *self,
+				  struct task_struct *task);
+void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos);
+void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos);
+int trace_pid_show(struct seq_file *m, void *v);
+void trace_free_pid_list(struct trace_pid_list *pid_list);
+int trace_pid_write(struct trace_pid_list *filtered_pids,
+		    struct trace_pid_list **new_pid_list,
+		    const char __user *ubuf, size_t cnt);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
+		   void *cond_data);
+void update_max_tr_single(struct trace_array *tr,
+			  struct task_struct *tsk, int cpu);
+
+#ifdef CONFIG_FSNOTIFY
+#define LATENCY_FS_NOTIFY
+#endif
+#endif /* CONFIG_TRACER_MAX_TRACE */
+
+#ifdef LATENCY_FS_NOTIFY
+void latency_fsnotify(struct trace_array *tr);
+#else
+static inline void latency_fsnotify(struct trace_array *tr) { }
+#endif
+
+#ifdef CONFIG_STACKTRACE
+void __trace_stack(struct trace_array *tr, unsigned int trace_ctx, int skip);
+#else
+static inline void __trace_stack(struct trace_array *tr, unsigned int trace_ctx,
+				 int skip)
+{
+}
+#endif /* CONFIG_STACKTRACE */
+
+void trace_last_func_repeats(struct trace_array *tr,
+			     struct trace_func_repeats *last_info,
+			     unsigned int trace_ctx);
+
+extern u64 ftrace_now(int cpu);
+
+extern void trace_find_cmdline(int pid, char comm[]);
+extern int trace_find_tgid(int pid);
+extern void trace_event_follow_fork(struct trace_array *tr, bool enable);
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern unsigned long ftrace_update_tot_cnt;
+extern unsigned long ftrace_number_of_pages;
+extern unsigned long ftrace_number_of_groups;
+void ftrace_init_trace_array(struct trace_array *tr);
+#else
+static inline void ftrace_init_trace_array(struct trace_array *tr) { }
+#endif
+#define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
+extern int DYN_FTRACE_TEST_NAME(void);
+#define DYN_FTRACE_TEST_NAME2 trace_selftest_dynamic_test_func2
+extern int DYN_FTRACE_TEST_NAME2(void);
+
+extern bool ring_buffer_expanded;
+extern bool tracing_selftest_disabled;
+
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+extern void __init disable_tracing_selftest(const char *reason);
+
+extern int trace_selftest_startup_function(struct tracer *trace,
+					   struct trace_array *tr);
+extern int trace_selftest_startup_function_graph(struct tracer *trace,
+						 struct trace_array *tr);
+extern int trace_selftest_startup_irqsoff(struct tracer *trace,
+					  struct trace_array *tr);
+extern int trace_selftest_startup_preemptoff(struct tracer *trace,
+					     struct trace_array *tr);
+extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
+						 struct trace_array *tr);
+extern int trace_selftest_startup_wakeup(struct tracer *trace,
+					 struct trace_array *tr);
+extern int trace_selftest_startup_nop(struct tracer *trace,
+					 struct trace_array *tr);
+extern int trace_selftest_startup_branch(struct tracer *trace,
+					 struct trace_array *tr);
+/*
+ * Tracer data references selftest functions that only occur
+ * on boot up. These can be __init functions. Thus, when selftests
+ * are enabled, then the tracers need to reference __init functions.
+ */
+#define __tracer_data		__refdata
+#else
+static inline void __init disable_tracing_selftest(const char *reason)
+{
+}
+/* Tracers are seldom changed. Optimize when selftests are disabled. */
+#define __tracer_data		__read_mostly
+#endif /* CONFIG_FTRACE_STARTUP_TEST */
+
+extern void *head_page(struct trace_array_cpu *data);
+extern unsigned long long ns2usecs(u64 nsec);
+extern int
+trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
+extern int
+trace_vprintk(unsigned long ip, const char *fmt, va_list args);
+extern int
+trace_array_vprintk(struct trace_array *tr,
+		    unsigned long ip, const char *fmt, va_list args);
+int trace_array_printk_buf(struct trace_buffer *buffer,
+			   unsigned long ip, const char *fmt, ...);
+void trace_printk_seq(struct trace_seq *s);
+enum print_line_t print_trace_line(struct trace_iterator *iter);
+
+extern char trace_find_mark(unsigned long long duration);
+
+struct ftrace_hash;
+
+struct ftrace_mod_load {
+	struct list_head	list;
+	char			*func;
+	char			*module;
+	int			 enable;
+};
+
+enum {
+	FTRACE_HASH_FL_MOD	= (1 << 0),
+};
+
+struct ftrace_hash {
+	unsigned long		size_bits;
+	struct hlist_head	*buckets;
+	unsigned long		count;
+	unsigned long		flags;
+	struct rcu_head		rcu;
+};
+
+struct ftrace_func_entry *
+ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip);
+
+static __always_inline bool ftrace_hash_empty(struct ftrace_hash *hash)
+{
+	return !hash || !(hash->count || (hash->flags & FTRACE_HASH_FL_MOD));
+}
+
+/* Standard output formatting function used for function return traces */
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+/* Flag options */
+#define TRACE_GRAPH_PRINT_OVERRUN       0x1
+#define TRACE_GRAPH_PRINT_CPU           0x2
+#define TRACE_GRAPH_PRINT_OVERHEAD      0x4
+#define TRACE_GRAPH_PRINT_PROC          0x8
+#define TRACE_GRAPH_PRINT_DURATION      0x10
+#define TRACE_GRAPH_PRINT_ABS_TIME      0x20
+#define TRACE_GRAPH_PRINT_REL_TIME      0x40
+#define TRACE_GRAPH_PRINT_IRQS          0x80
+#define TRACE_GRAPH_PRINT_TAIL          0x100
+#define TRACE_GRAPH_SLEEP_TIME          0x200
+#define TRACE_GRAPH_GRAPH_TIME          0x400
+#define TRACE_GRAPH_PRINT_FILL_SHIFT	28
+#define TRACE_GRAPH_PRINT_FILL_MASK	(0x3 << TRACE_GRAPH_PRINT_FILL_SHIFT)
+
+extern void ftrace_graph_sleep_time_control(bool enable);
+
+#ifdef CONFIG_FUNCTION_PROFILER
+extern void ftrace_graph_graph_time_control(bool enable);
+#else
+static inline void ftrace_graph_graph_time_control(bool enable) { }
+#endif
+
+extern enum print_line_t
+print_graph_function_flags(struct trace_iterator *iter, u32 flags);
+extern void print_graph_headers_flags(struct seq_file *s, u32 flags);
+extern void
+trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
+extern void graph_trace_open(struct trace_iterator *iter);
+extern void graph_trace_close(struct trace_iterator *iter);
+extern int __trace_graph_entry(struct trace_array *tr,
+			       struct ftrace_graph_ent *trace,
+			       unsigned int trace_ctx);
+extern void __trace_graph_return(struct trace_array *tr,
+				 struct ftrace_graph_ret *trace,
+				 unsigned int trace_ctx);
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern struct ftrace_hash __rcu *ftrace_graph_hash;
+extern struct ftrace_hash __rcu *ftrace_graph_notrace_hash;
+
+static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
+{
+	unsigned long addr = trace->func;
+	int ret = 0;
+	struct ftrace_hash *hash;
+
+	preempt_disable_notrace();
+
+	/*
+	 * Have to open code "rcu_dereference_sched()" because the
+	 * function graph tracer can be called when RCU is not
+	 * "watching".
+	 * Protected with schedule_on_each_cpu(ftrace_sync)
+	 */
+	hash = rcu_dereference_protected(ftrace_graph_hash, !preemptible());
+
+	if (ftrace_hash_empty(hash)) {
+		ret = 1;
+		goto out;
+	}
+
+	if (ftrace_lookup_ip(hash, addr)) {
+
+		/*
+		 * This needs to be cleared on the return functions
+		 * when the depth is zero.
+		 */
+		trace_recursion_set(TRACE_GRAPH_BIT);
+		trace_recursion_set_depth(trace->depth);
+
+		/*
+		 * If no irqs are to be traced, but a set_graph_function
+		 * is set, and called by an interrupt handler, we still
+		 * want to trace it.
+		 */
+		if (in_hardirq())
+			trace_recursion_set(TRACE_IRQ_BIT);
+		else
+			trace_recursion_clear(TRACE_IRQ_BIT);
+		ret = 1;
+	}
+
+out:
+	preempt_enable_notrace();
+	return ret;
+}
+
+static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
+{
+	if (trace_recursion_test(TRACE_GRAPH_BIT) &&
+	    trace->depth == trace_recursion_depth())
+		trace_recursion_clear(TRACE_GRAPH_BIT);
+}
+
+static inline int ftrace_graph_notrace_addr(unsigned long addr)
+{
+	int ret = 0;
+	struct ftrace_hash *notrace_hash;
+
+	preempt_disable_notrace();
+
+	/*
+	 * Have to open code "rcu_dereference_sched()" because the
+	 * function graph tracer can be called when RCU is not
+	 * "watching".
+	 * Protected with schedule_on_each_cpu(ftrace_sync)
+	 */
+	notrace_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
+						 !preemptible());
+
+	if (ftrace_lookup_ip(notrace_hash, addr))
+		ret = 1;
+
+	preempt_enable_notrace();
+	return ret;
+}
+#else
+static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
+{
+	return 1;
+}
+
+static inline int ftrace_graph_notrace_addr(unsigned long addr)
+{
+	return 0;
+}
+static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
+{ }
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+extern unsigned int fgraph_max_depth;
+
+static inline bool ftrace_graph_ignore_func(struct ftrace_graph_ent *trace)
+{
+	/* trace it when it is-nested-in or is a function enabled. */
+	return !(trace_recursion_test(TRACE_GRAPH_BIT) ||
+		 ftrace_graph_addr(trace)) ||
+		(trace->depth < 0) ||
+		(fgraph_max_depth && trace->depth >= fgraph_max_depth);
+}
+
+#else /* CONFIG_FUNCTION_GRAPH_TRACER */
+static inline enum print_line_t
+print_graph_function_flags(struct trace_iterator *iter, u32 flags)
+{
+	return TRACE_TYPE_UNHANDLED;
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+extern struct list_head ftrace_pids;
+
+#ifdef CONFIG_FUNCTION_TRACER
+
+#define FTRACE_PID_IGNORE	-1
+#define FTRACE_PID_TRACE	-2
+
+struct ftrace_func_command {
+	struct list_head	list;
+	char			*name;
+	int			(*func)(struct trace_array *tr,
+					struct ftrace_hash *hash,
+					char *func, char *cmd,
+					char *params, int enable);
+};
+extern bool ftrace_filter_param __initdata;
+static inline int ftrace_trace_task(struct trace_array *tr)
+{
+	return this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid) !=
+		FTRACE_PID_IGNORE;
+}
+extern int ftrace_is_dead(void);
+int ftrace_create_function_files(struct trace_array *tr,
+				 struct dentry *parent);
+void ftrace_destroy_function_files(struct trace_array *tr);
+int ftrace_allocate_ftrace_ops(struct trace_array *tr);
+void ftrace_free_ftrace_ops(struct trace_array *tr);
+void ftrace_init_global_array_ops(struct trace_array *tr);
+void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func);
+void ftrace_reset_array_ops(struct trace_array *tr);
+void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer);
+void ftrace_init_tracefs_toplevel(struct trace_array *tr,
+				  struct dentry *d_tracer);
+void ftrace_clear_pids(struct trace_array *tr);
+int init_function_trace(void);
+void ftrace_pid_follow_fork(struct trace_array *tr, bool enable);
+#else
+static inline int ftrace_trace_task(struct trace_array *tr)
+{
+	return 1;
+}
+static inline int ftrace_is_dead(void) { return 0; }
+static inline int
+ftrace_create_function_files(struct trace_array *tr,
+			     struct dentry *parent)
+{
+	return 0;
+}
+static inline int ftrace_allocate_ftrace_ops(struct trace_array *tr)
+{
+	return 0;
+}
+static inline void ftrace_free_ftrace_ops(struct trace_array *tr) { }
+static inline void ftrace_destroy_function_files(struct trace_array *tr) { }
+static inline __init void
+ftrace_init_global_array_ops(struct trace_array *tr) { }
+static inline void ftrace_reset_array_ops(struct trace_array *tr) { }
+static inline void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d) { }
+static inline void ftrace_init_tracefs_toplevel(struct trace_array *tr, struct dentry *d) { }
+static inline void ftrace_clear_pids(struct trace_array *tr) { }
+static inline int init_function_trace(void) { return 0; }
+static inline void ftrace_pid_follow_fork(struct trace_array *tr, bool enable) { }
+/* ftace_func_t type is not defined, use macro instead of static inline */
+#define ftrace_init_array_ops(tr, func) do { } while (0)
+#endif /* CONFIG_FUNCTION_TRACER */
+
+#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
+
+struct ftrace_probe_ops {
+	void			(*func)(unsigned long ip,
+					unsigned long parent_ip,
+					struct trace_array *tr,
+					struct ftrace_probe_ops *ops,
+					void *data);
+	int			(*init)(struct ftrace_probe_ops *ops,
+					struct trace_array *tr,
+					unsigned long ip, void *init_data,
+					void **data);
+	void			(*free)(struct ftrace_probe_ops *ops,
+					struct trace_array *tr,
+					unsigned long ip, void *data);
+	int			(*print)(struct seq_file *m,
+					 unsigned long ip,
+					 struct ftrace_probe_ops *ops,
+					 void *data);
+};
+
+struct ftrace_func_mapper;
+typedef int (*ftrace_mapper_func)(void *data);
+
+struct ftrace_func_mapper *allocate_ftrace_func_mapper(void);
+void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
+					   unsigned long ip);
+int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
+			       unsigned long ip, void *data);
+void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
+				   unsigned long ip);
+void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
+			     ftrace_mapper_func free_func);
+
+extern int
+register_ftrace_function_probe(char *glob, struct trace_array *tr,
+			       struct ftrace_probe_ops *ops, void *data);
+extern int
+unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
+				      struct ftrace_probe_ops *ops);
+extern void clear_ftrace_function_probes(struct trace_array *tr);
+
+int register_ftrace_command(struct ftrace_func_command *cmd);
+int unregister_ftrace_command(struct ftrace_func_command *cmd);
+
+void ftrace_create_filter_files(struct ftrace_ops *ops,
+				struct dentry *parent);
+void ftrace_destroy_filter_files(struct ftrace_ops *ops);
+
+extern int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
+			     int len, int reset);
+extern int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
+			      int len, int reset);
+#else
+struct ftrace_func_command;
+
+static inline __init int register_ftrace_command(struct ftrace_func_command *cmd)
+{
+	return -EINVAL;
+}
+static inline __init int unregister_ftrace_command(char *cmd_name)
+{
+	return -EINVAL;
+}
+static inline void clear_ftrace_function_probes(struct trace_array *tr)
+{
+}
+
+/*
+ * The ops parameter passed in is usually undefined.
+ * This must be a macro.
+ */
+#define ftrace_create_filter_files(ops, parent) do { } while (0)
+#define ftrace_destroy_filter_files(ops) do { } while (0)
+#endif /* CONFIG_FUNCTION_TRACER && CONFIG_DYNAMIC_FTRACE */
+
+bool ftrace_event_is_function(struct trace_event_call *call);
+
+/*
+ * struct trace_parser - servers for reading the user input separated by spaces
+ * @cont: set if the input is not complete - no final space char was found
+ * @buffer: holds the parsed user input
+ * @idx: user input length
+ * @size: buffer size
+ */
+struct trace_parser {
+	bool		cont;
+	char		*buffer;
+	unsigned	idx;
+	unsigned	size;
+};
+
+static inline bool trace_parser_loaded(struct trace_parser *parser)
+{
+	return (parser->idx != 0);
+}
+
+static inline bool trace_parser_cont(struct trace_parser *parser)
+{
+	return parser->cont;
+}
+
+static inline void trace_parser_clear(struct trace_parser *parser)
+{
+	parser->cont = false;
+	parser->idx = 0;
+}
+
+extern int trace_parser_get_init(struct trace_parser *parser, int size);
+extern void trace_parser_put(struct trace_parser *parser);
+extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
+	size_t cnt, loff_t *ppos);
+
+/*
+ * Only create function graph options if function graph is configured.
+ */
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+# define FGRAPH_FLAGS						\
+		C(DISPLAY_GRAPH,	"display-graph"),
+#else
+# define FGRAPH_FLAGS
+#endif
+
+#ifdef CONFIG_BRANCH_TRACER
+# define BRANCH_FLAGS					\
+		C(BRANCH,		"branch"),
+#else
+# define BRANCH_FLAGS
+#endif
+
+#ifdef CONFIG_FUNCTION_TRACER
+# define FUNCTION_FLAGS						\
+		C(FUNCTION,		"function-trace"),	\
+		C(FUNC_FORK,		"function-fork"),
+# define FUNCTION_DEFAULT_FLAGS		TRACE_ITER_FUNCTION
+#else
+# define FUNCTION_FLAGS
+# define FUNCTION_DEFAULT_FLAGS		0UL
+# define TRACE_ITER_FUNC_FORK		0UL
+#endif
+
+#ifdef CONFIG_STACKTRACE
+# define STACK_FLAGS				\
+		C(STACKTRACE,		"stacktrace"),
+#else
+# define STACK_FLAGS
+#endif
+
+/*
+ * trace_iterator_flags is an enumeration that defines bit
+ * positions into trace_flags that controls the output.
+ *
+ * NOTE: These bits must match the trace_options array in
+ *       trace.c (this macro guarantees it).
+ */
+#define TRACE_FLAGS						\
+		C(PRINT_PARENT,		"print-parent"),	\
+		C(SYM_OFFSET,		"sym-offset"),		\
+		C(SYM_ADDR,		"sym-addr"),		\
+		C(VERBOSE,		"verbose"),		\
+		C(RAW,			"raw"),			\
+		C(HEX,			"hex"),			\
+		C(BIN,			"bin"),			\
+		C(BLOCK,		"block"),		\
+		C(PRINTK,		"trace_printk"),	\
+		C(ANNOTATE,		"annotate"),		\
+		C(USERSTACKTRACE,	"userstacktrace"),	\
+		C(SYM_USEROBJ,		"sym-userobj"),		\
+		C(PRINTK_MSGONLY,	"printk-msg-only"),	\
+		C(CONTEXT_INFO,		"context-info"),   /* Print pid/cpu/time */ \
+		C(LATENCY_FMT,		"latency-format"),	\
+		C(RECORD_CMD,		"record-cmd"),		\
+		C(RECORD_TGID,		"record-tgid"),		\
+		C(OVERWRITE,		"overwrite"),		\
+		C(STOP_ON_FREE,		"disable_on_free"),	\
+		C(IRQ_INFO,		"irq-info"),		\
+		C(MARKERS,		"markers"),		\
+		C(EVENT_FORK,		"event-fork"),		\
+		C(PAUSE_ON_TRACE,	"pause-on-trace"),	\
+		C(HASH_PTR,		"hash-ptr"),	/* Print hashed pointer */ \
+		FUNCTION_FLAGS					\
+		FGRAPH_FLAGS					\
+		STACK_FLAGS					\
+		BRANCH_FLAGS
+
+/*
+ * By defining C, we can make TRACE_FLAGS a list of bit names
+ * that will define the bits for the flag masks.
+ */
+#undef C
+#define C(a, b) TRACE_ITER_##a##_BIT
+
+enum trace_iterator_bits {
+	TRACE_FLAGS
+	/* Make sure we don't go more than we have bits for */
+	TRACE_ITER_LAST_BIT
+};
+
+/*
+ * By redefining C, we can make TRACE_FLAGS a list of masks that
+ * use the bits as defined above.
+ */
+#undef C
+#define C(a, b) TRACE_ITER_##a = (1 << TRACE_ITER_##a##_BIT)
+
+enum trace_iterator_flags { TRACE_FLAGS };
+
+/*
+ * TRACE_ITER_SYM_MASK masks the options in trace_flags that
+ * control the output of kernel symbols.
+ */
+#define TRACE_ITER_SYM_MASK \
+	(TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
+
+extern struct tracer nop_trace;
+
+#ifdef CONFIG_BRANCH_TRACER
+extern int enable_branch_tracing(struct trace_array *tr);
+extern void disable_branch_tracing(void);
+static inline int trace_branch_enable(struct trace_array *tr)
+{
+	if (tr->trace_flags & TRACE_ITER_BRANCH)
+		return enable_branch_tracing(tr);
+	return 0;
+}
+static inline void trace_branch_disable(void)
+{
+	/* due to races, always disable */
+	disable_branch_tracing();
+}
+#else
+static inline int trace_branch_enable(struct trace_array *tr)
+{
+	return 0;
+}
+static inline void trace_branch_disable(void)
+{
+}
+#endif /* CONFIG_BRANCH_TRACER */
+
+/* set ring buffers to default size if not already done so */
+int tracing_update_buffers(void);
+
+struct ftrace_event_field {
+	struct list_head	link;
+	const char		*name;
+	const char		*type;
+	int			filter_type;
+	int			offset;
+	int			size;
+	int			is_signed;
+	int			len;
+};
+
+struct prog_entry;
+
+struct event_filter {
+	struct prog_entry __rcu	*prog;
+	char			*filter_string;
+};
+
+struct event_subsystem {
+	struct list_head	list;
+	const char		*name;
+	struct event_filter	*filter;
+	int			ref_count;
+};
+
+struct trace_subsystem_dir {
+	struct list_head		list;
+	struct event_subsystem		*subsystem;
+	struct trace_array		*tr;
+	struct dentry			*entry;
+	int				ref_count;
+	int				nr_events;
+};
+
+extern int call_filter_check_discard(struct trace_event_call *call, void *rec,
+				     struct trace_buffer *buffer,
+				     struct ring_buffer_event *event);
+
+void trace_buffer_unlock_commit_regs(struct trace_array *tr,
+				     struct trace_buffer *buffer,
+				     struct ring_buffer_event *event,
+				     unsigned int trcace_ctx,
+				     struct pt_regs *regs);
+
+static inline void trace_buffer_unlock_commit(struct trace_array *tr,
+					      struct trace_buffer *buffer,
+					      struct ring_buffer_event *event,
+					      unsigned int trace_ctx)
+{
+	trace_buffer_unlock_commit_regs(tr, buffer, event, trace_ctx, NULL);
+}
+
+DECLARE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
+DECLARE_PER_CPU(int, trace_buffered_event_cnt);
+void trace_buffered_event_disable(void);
+void trace_buffered_event_enable(void);
+
+static inline void
+__trace_event_discard_commit(struct trace_buffer *buffer,
+			     struct ring_buffer_event *event)
+{
+	if (this_cpu_read(trace_buffered_event) == event) {
+		/* Simply release the temp buffer and enable preemption */
+		this_cpu_dec(trace_buffered_event_cnt);
+		preempt_enable_notrace();
+		return;
+	}
+	/* ring_buffer_discard_commit() enables preemption */
+	ring_buffer_discard_commit(buffer, event);
+}
+
+/*
+ * Helper function for event_trigger_unlock_commit{_regs}().
+ * If there are event triggers attached to this event that requires
+ * filtering against its fields, then they will be called as the
+ * entry already holds the field information of the current event.
+ *
+ * It also checks if the event should be discarded or not.
+ * It is to be discarded if the event is soft disabled and the
+ * event was only recorded to process triggers, or if the event
+ * filter is active and this event did not match the filters.
+ *
+ * Returns true if the event is discarded, false otherwise.
+ */
+static inline bool
+__event_trigger_test_discard(struct trace_event_file *file,
+			     struct trace_buffer *buffer,
+			     struct ring_buffer_event *event,
+			     void *entry,
+			     enum event_trigger_type *tt)
+{
+	unsigned long eflags = file->flags;
+
+	if (eflags & EVENT_FILE_FL_TRIGGER_COND)
+		*tt = event_triggers_call(file, buffer, entry, event);
+
+	if (likely(!(file->flags & (EVENT_FILE_FL_SOFT_DISABLED |
+				    EVENT_FILE_FL_FILTERED |
+				    EVENT_FILE_FL_PID_FILTER))))
+		return false;
+
+	if (file->flags & EVENT_FILE_FL_SOFT_DISABLED)
+		goto discard;
+
+	if (file->flags & EVENT_FILE_FL_FILTERED &&
+	    !filter_match_preds(file->filter, entry))
+		goto discard;
+
+	if ((file->flags & EVENT_FILE_FL_PID_FILTER) &&
+	    trace_event_ignore_this_pid(file))
+		goto discard;
+
+	return false;
+ discard:
+	__trace_event_discard_commit(buffer, event);
+	return true;
+}
+
+/**
+ * event_trigger_unlock_commit - handle triggers and finish event commit
+ * @file: The file pointer associated with the event
+ * @buffer: The ring buffer that the event is being written to
+ * @event: The event meta data in the ring buffer
+ * @entry: The event itself
+ * @trace_ctx: The tracing context flags.
+ *
+ * This is a helper function to handle triggers that require data
+ * from the event itself. It also tests the event against filters and
+ * if the event is soft disabled and should be discarded.
+ */
+static inline void
+event_trigger_unlock_commit(struct trace_event_file *file,
+			    struct trace_buffer *buffer,
+			    struct ring_buffer_event *event,
+			    void *entry, unsigned int trace_ctx)
+{
+	enum event_trigger_type tt = ETT_NONE;
+
+	if (!__event_trigger_test_discard(file, buffer, event, entry, &tt))
+		trace_buffer_unlock_commit(file->tr, buffer, event, trace_ctx);
+
+	if (tt)
+		event_triggers_post_call(file, tt);
+}
+
+#define FILTER_PRED_INVALID	((unsigned short)-1)
+#define FILTER_PRED_IS_RIGHT	(1 << 15)
+#define FILTER_PRED_FOLD	(1 << 15)
+
+/*
+ * The max preds is the size of unsigned short with
+ * two flags at the MSBs. One bit is used for both the IS_RIGHT
+ * and FOLD flags. The other is reserved.
+ *
+ * 2^14 preds is way more than enough.
+ */
+#define MAX_FILTER_PRED		16384
+
+struct filter_pred;
+struct regex;
+
+typedef int (*regex_match_func)(char *str, struct regex *r, int len);
+
+enum regex_type {
+	MATCH_FULL = 0,
+	MATCH_FRONT_ONLY,
+	MATCH_MIDDLE_ONLY,
+	MATCH_END_ONLY,
+	MATCH_GLOB,
+	MATCH_INDEX,
+};
+
+struct regex {
+	char			pattern[MAX_FILTER_STR_VAL];
+	int			len;
+	int			field_len;
+	regex_match_func	match;
+};
+
+static inline bool is_string_field(struct ftrace_event_field *field)
+{
+	return field->filter_type == FILTER_DYN_STRING ||
+	       field->filter_type == FILTER_RDYN_STRING ||
+	       field->filter_type == FILTER_STATIC_STRING ||
+	       field->filter_type == FILTER_PTR_STRING ||
+	       field->filter_type == FILTER_COMM;
+}
+
+static inline bool is_function_field(struct ftrace_event_field *field)
+{
+	return field->filter_type == FILTER_TRACE_FN;
+}
+
+extern enum regex_type
+filter_parse_regex(char *buff, int len, char **search, int *not);
+extern void print_event_filter(struct trace_event_file *file,
+			       struct trace_seq *s);
+extern int apply_event_filter(struct trace_event_file *file,
+			      char *filter_string);
+extern int apply_subsystem_event_filter(struct trace_subsystem_dir *dir,
+					char *filter_string);
+extern void print_subsystem_event_filter(struct event_subsystem *system,
+					 struct trace_seq *s);
+extern int filter_assign_type(const char *type);
+extern int create_event_filter(struct trace_array *tr,
+			       struct trace_event_call *call,
+			       char *filter_str, bool set_str,
+			       struct event_filter **filterp);
+extern void free_event_filter(struct event_filter *filter);
+
+struct ftrace_event_field *
+trace_find_event_field(struct trace_event_call *call, char *name);
+
+extern void trace_event_enable_cmd_record(bool enable);
+extern void trace_event_enable_tgid_record(bool enable);
+
+extern int event_trace_init(void);
+extern int init_events(void);
+extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr);
+extern int event_trace_del_tracer(struct trace_array *tr);
+extern void __trace_early_add_events(struct trace_array *tr);
+
+extern struct trace_event_file *__find_event_file(struct trace_array *tr,
+						  const char *system,
+						  const char *event);
+extern struct trace_event_file *find_event_file(struct trace_array *tr,
+						const char *system,
+						const char *event);
+
+static inline void *event_file_data(struct file *filp)
+{
+	return READ_ONCE(file_inode(filp)->i_private);
+}
+
+extern struct mutex event_mutex;
+extern struct list_head ftrace_events;
+
+extern const struct file_operations event_trigger_fops;
+extern const struct file_operations event_hist_fops;
+extern const struct file_operations event_hist_debug_fops;
+extern const struct file_operations event_inject_fops;
+
+#ifdef CONFIG_HIST_TRIGGERS
+extern int register_trigger_hist_cmd(void);
+extern int register_trigger_hist_enable_disable_cmds(void);
+#else
+static inline int register_trigger_hist_cmd(void) { return 0; }
+static inline int register_trigger_hist_enable_disable_cmds(void) { return 0; }
+#endif
+
+extern int register_trigger_cmds(void);
+extern void clear_event_triggers(struct trace_array *tr);
+
+enum {
+	EVENT_TRIGGER_FL_PROBE		= BIT(0),
+};
+
+struct event_trigger_data {
+	unsigned long			count;
+	int				ref;
+	int				flags;
+	struct event_trigger_ops	*ops;
+	struct event_command		*cmd_ops;
+	struct event_filter __rcu	*filter;
+	char				*filter_str;
+	void				*private_data;
+	bool				paused;
+	bool				paused_tmp;
+	struct list_head		list;
+	char				*name;
+	struct list_head		named_list;
+	struct event_trigger_data	*named_data;
+};
+
+/* Avoid typos */
+#define ENABLE_EVENT_STR	"enable_event"
+#define DISABLE_EVENT_STR	"disable_event"
+#define ENABLE_HIST_STR		"enable_hist"
+#define DISABLE_HIST_STR	"disable_hist"
+
+struct enable_trigger_data {
+	struct trace_event_file		*file;
+	bool				enable;
+	bool				hist;
+};
+
+extern int event_enable_trigger_print(struct seq_file *m,
+				      struct event_trigger_data *data);
+extern void event_enable_trigger_free(struct event_trigger_data *data);
+extern int event_enable_trigger_parse(struct event_command *cmd_ops,
+				      struct trace_event_file *file,
+				      char *glob, char *cmd,
+				      char *param_and_filter);
+extern int event_enable_register_trigger(char *glob,
+					 struct event_trigger_data *data,
+					 struct trace_event_file *file);
+extern void event_enable_unregister_trigger(char *glob,
+					    struct event_trigger_data *test,
+					    struct trace_event_file *file);
+extern void trigger_data_free(struct event_trigger_data *data);
+extern int event_trigger_init(struct event_trigger_data *data);
+extern int trace_event_trigger_enable_disable(struct trace_event_file *file,
+					      int trigger_enable);
+extern void update_cond_flag(struct trace_event_file *file);
+extern int set_trigger_filter(char *filter_str,
+			      struct event_trigger_data *trigger_data,
+			      struct trace_event_file *file);
+extern struct event_trigger_data *find_named_trigger(const char *name);
+extern bool is_named_trigger(struct event_trigger_data *test);
+extern int save_named_trigger(const char *name,
+			      struct event_trigger_data *data);
+extern void del_named_trigger(struct event_trigger_data *data);
+extern void pause_named_trigger(struct event_trigger_data *data);
+extern void unpause_named_trigger(struct event_trigger_data *data);
+extern void set_named_trigger_data(struct event_trigger_data *data,
+				   struct event_trigger_data *named_data);
+extern struct event_trigger_data *
+get_named_trigger_data(struct event_trigger_data *data);
+extern int register_event_command(struct event_command *cmd);
+extern int unregister_event_command(struct event_command *cmd);
+extern int register_trigger_hist_enable_disable_cmds(void);
+extern bool event_trigger_check_remove(const char *glob);
+extern bool event_trigger_empty_param(const char *param);
+extern int event_trigger_separate_filter(char *param_and_filter, char **param,
+					 char **filter, bool param_required);
+extern struct event_trigger_data *
+event_trigger_alloc(struct event_command *cmd_ops,
+		    char *cmd,
+		    char *param,
+		    void *private_data);
+extern int event_trigger_parse_num(char *trigger,
+				   struct event_trigger_data *trigger_data);
+extern int event_trigger_set_filter(struct event_command *cmd_ops,
+				    struct trace_event_file *file,
+				    char *param,
+				    struct event_trigger_data *trigger_data);
+extern void event_trigger_reset_filter(struct event_command *cmd_ops,
+				       struct event_trigger_data *trigger_data);
+extern int event_trigger_register(struct event_command *cmd_ops,
+				  struct trace_event_file *file,
+				  char *glob,
+				  struct event_trigger_data *trigger_data);
+extern void event_trigger_unregister(struct event_command *cmd_ops,
+				     struct trace_event_file *file,
+				     char *glob,
+				     struct event_trigger_data *trigger_data);
+
+extern void event_file_get(struct trace_event_file *file);
+extern void event_file_put(struct trace_event_file *file);
+
+/**
+ * struct event_trigger_ops - callbacks for trace event triggers
+ *
+ * The methods in this structure provide per-event trigger hooks for
+ * various trigger operations.
+ *
+ * The @init and @free methods are used during trigger setup and
+ * teardown, typically called from an event_command's @parse()
+ * function implementation.
+ *
+ * The @print method is used to print the trigger spec.
+ *
+ * The @trigger method is the function that actually implements the
+ * trigger and is called in the context of the triggering event
+ * whenever that event occurs.
+ *
+ * All the methods below, except for @init() and @free(), must be
+ * implemented.
+ *
+ * @trigger: The trigger 'probe' function called when the triggering
+ *	event occurs.  The data passed into this callback is the data
+ *	that was supplied to the event_command @reg() function that
+ *	registered the trigger (see struct event_command) along with
+ *	the trace record, rec.
+ *
+ * @init: An optional initialization function called for the trigger
+ *	when the trigger is registered (via the event_command reg()
+ *	function).  This can be used to perform per-trigger
+ *	initialization such as incrementing a per-trigger reference
+ *	count, for instance.  This is usually implemented by the
+ *	generic utility function @event_trigger_init() (see
+ *	trace_event_triggers.c).
+ *
+ * @free: An optional de-initialization function called for the
+ *	trigger when the trigger is unregistered (via the
+ *	event_command @reg() function).  This can be used to perform
+ *	per-trigger de-initialization such as decrementing a
+ *	per-trigger reference count and freeing corresponding trigger
+ *	data, for instance.  This is usually implemented by the
+ *	generic utility function @event_trigger_free() (see
+ *	trace_event_triggers.c).
+ *
+ * @print: The callback function invoked to have the trigger print
+ *	itself.  This is usually implemented by a wrapper function
+ *	that calls the generic utility function @event_trigger_print()
+ *	(see trace_event_triggers.c).
+ */
+struct event_trigger_ops {
+	void			(*trigger)(struct event_trigger_data *data,
+					   struct trace_buffer *buffer,
+					   void *rec,
+					   struct ring_buffer_event *rbe);
+	int			(*init)(struct event_trigger_data *data);
+	void			(*free)(struct event_trigger_data *data);
+	int			(*print)(struct seq_file *m,
+					 struct event_trigger_data *data);
+};
+
+/**
+ * struct event_command - callbacks and data members for event commands
+ *
+ * Event commands are invoked by users by writing the command name
+ * into the 'trigger' file associated with a trace event.  The
+ * parameters associated with a specific invocation of an event
+ * command are used to create an event trigger instance, which is
+ * added to the list of trigger instances associated with that trace
+ * event.  When the event is hit, the set of triggers associated with
+ * that event is invoked.
+ *
+ * The data members in this structure provide per-event command data
+ * for various event commands.
+ *
+ * All the data members below, except for @post_trigger, must be set
+ * for each event command.
+ *
+ * @name: The unique name that identifies the event command.  This is
+ *	the name used when setting triggers via trigger files.
+ *
+ * @trigger_type: A unique id that identifies the event command
+ *	'type'.  This value has two purposes, the first to ensure that
+ *	only one trigger of the same type can be set at a given time
+ *	for a particular event e.g. it doesn't make sense to have both
+ *	a traceon and traceoff trigger attached to a single event at
+ *	the same time, so traceon and traceoff have the same type
+ *	though they have different names.  The @trigger_type value is
+ *	also used as a bit value for deferring the actual trigger
+ *	action until after the current event is finished.  Some
+ *	commands need to do this if they themselves log to the trace
+ *	buffer (see the @post_trigger() member below).  @trigger_type
+ *	values are defined by adding new values to the trigger_type
+ *	enum in include/linux/trace_events.h.
+ *
+ * @flags: See the enum event_command_flags below.
+ *
+ * All the methods below, except for @set_filter() and @unreg_all(),
+ * must be implemented.
+ *
+ * @parse: The callback function responsible for parsing and
+ *	registering the trigger written to the 'trigger' file by the
+ *	user.  It allocates the trigger instance and registers it with
+ *	the appropriate trace event.  It makes use of the other
+ *	event_command callback functions to orchestrate this, and is
+ *	usually implemented by the generic utility function
+ *	@event_trigger_callback() (see trace_event_triggers.c).
+ *
+ * @reg: Adds the trigger to the list of triggers associated with the
+ *	event, and enables the event trigger itself, after
+ *	initializing it (via the event_trigger_ops @init() function).
+ *	This is also where commands can use the @trigger_type value to
+ *	make the decision as to whether or not multiple instances of
+ *	the trigger should be allowed.  This is usually implemented by
+ *	the generic utility function @register_trigger() (see
+ *	trace_event_triggers.c).
+ *
+ * @unreg: Removes the trigger from the list of triggers associated
+ *	with the event, and disables the event trigger itself, after
+ *	initializing it (via the event_trigger_ops @free() function).
+ *	This is usually implemented by the generic utility function
+ *	@unregister_trigger() (see trace_event_triggers.c).
+ *
+ * @unreg_all: An optional function called to remove all the triggers
+ *	from the list of triggers associated with the event.  Called
+ *	when a trigger file is opened in truncate mode.
+ *
+ * @set_filter: An optional function called to parse and set a filter
+ *	for the trigger.  If no @set_filter() method is set for the
+ *	event command, filters set by the user for the command will be
+ *	ignored.  This is usually implemented by the generic utility
+ *	function @set_trigger_filter() (see trace_event_triggers.c).
+ *
+ * @get_trigger_ops: The callback function invoked to retrieve the
+ *	event_trigger_ops implementation associated with the command.
+ *	This callback function allows a single event_command to
+ *	support multiple trigger implementations via different sets of
+ *	event_trigger_ops, depending on the value of the @param
+ *	string.
+ */
+struct event_command {
+	struct list_head	list;
+	char			*name;
+	enum event_trigger_type	trigger_type;
+	int			flags;
+	int			(*parse)(struct event_command *cmd_ops,
+					 struct trace_event_file *file,
+					 char *glob, char *cmd,
+					 char *param_and_filter);
+	int			(*reg)(char *glob,
+				       struct event_trigger_data *data,
+				       struct trace_event_file *file);
+	void			(*unreg)(char *glob,
+					 struct event_trigger_data *data,
+					 struct trace_event_file *file);
+	void			(*unreg_all)(struct trace_event_file *file);
+	int			(*set_filter)(char *filter_str,
+					      struct event_trigger_data *data,
+					      struct trace_event_file *file);
+	struct event_trigger_ops *(*get_trigger_ops)(char *cmd, char *param);
+};
+
+/**
+ * enum event_command_flags - flags for struct event_command
+ *
+ * @POST_TRIGGER: A flag that says whether or not this command needs
+ *	to have its action delayed until after the current event has
+ *	been closed.  Some triggers need to avoid being invoked while
+ *	an event is currently in the process of being logged, since
+ *	the trigger may itself log data into the trace buffer.  Thus
+ *	we make sure the current event is committed before invoking
+ *	those triggers.  To do that, the trigger invocation is split
+ *	in two - the first part checks the filter using the current
+ *	trace record; if a command has the @post_trigger flag set, it
+ *	sets a bit for itself in the return value, otherwise it
+ *	directly invokes the trigger.  Once all commands have been
+ *	either invoked or set their return flag, the current record is
+ *	either committed or discarded.  At that point, if any commands
+ *	have deferred their triggers, those commands are finally
+ *	invoked following the close of the current event.  In other
+ *	words, if the event_trigger_ops @func() probe implementation
+ *	itself logs to the trace buffer, this flag should be set,
+ *	otherwise it can be left unspecified.
+ *
+ * @NEEDS_REC: A flag that says whether or not this command needs
+ *	access to the trace record in order to perform its function,
+ *	regardless of whether or not it has a filter associated with
+ *	it (filters make a trigger require access to the trace record
+ *	but are not always present).
+ */
+enum event_command_flags {
+	EVENT_CMD_FL_POST_TRIGGER	= 1,
+	EVENT_CMD_FL_NEEDS_REC		= 2,
+};
+
+static inline bool event_command_post_trigger(struct event_command *cmd_ops)
+{
+	return cmd_ops->flags & EVENT_CMD_FL_POST_TRIGGER;
+}
+
+static inline bool event_command_needs_rec(struct event_command *cmd_ops)
+{
+	return cmd_ops->flags & EVENT_CMD_FL_NEEDS_REC;
+}
+
+extern int trace_event_enable_disable(struct trace_event_file *file,
+				      int enable, int soft_disable);
+extern int tracing_alloc_snapshot(void);
+extern void tracing_snapshot_cond(struct trace_array *tr, void *cond_data);
+extern int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update);
+
+extern int tracing_snapshot_cond_disable(struct trace_array *tr);
+extern void *tracing_cond_snapshot_data(struct trace_array *tr);
+
+extern const char *__start___trace_bprintk_fmt[];
+extern const char *__stop___trace_bprintk_fmt[];
+
+extern const char *__start___tracepoint_str[];
+extern const char *__stop___tracepoint_str[];
+
+void trace_printk_control(bool enabled);
+void trace_printk_start_comm(void);
+int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set);
+int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled);
+
+/* Used from boot time tracer */
+extern int trace_set_options(struct trace_array *tr, char *option);
+extern int tracing_set_tracer(struct trace_array *tr, const char *buf);
+extern ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
+					  unsigned long size, int cpu_id);
+extern int tracing_set_cpumask(struct trace_array *tr,
+				cpumask_var_t tracing_cpumask_new);
+
+
+#define MAX_EVENT_NAME_LEN	64
+
+extern ssize_t trace_parse_run_command(struct file *file,
+		const char __user *buffer, size_t count, loff_t *ppos,
+		int (*createfn)(const char *));
+
+extern unsigned int err_pos(char *cmd, const char *str);
+extern void tracing_log_err(struct trace_array *tr,
+			    const char *loc, const char *cmd,
+			    const char **errs, u8 type, u16 pos);
+
+/*
+ * Normal trace_printk() and friends allocates special buffers
+ * to do the manipulation, as well as saves the print formats
+ * into sections to display. But the trace infrastructure wants
+ * to use these without the added overhead at the price of being
+ * a bit slower (used mainly for warnings, where we don't care
+ * about performance). The internal_trace_puts() is for such
+ * a purpose.
+ */
+#define internal_trace_puts(str) __trace_puts(_THIS_IP_, str, strlen(str))
+
+#undef FTRACE_ENTRY
+#define FTRACE_ENTRY(call, struct_name, id, tstruct, print)	\
+	extern struct trace_event_call					\
+	__aligned(4) event_##call;
+#undef FTRACE_ENTRY_DUP
+#define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print)	\
+	FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
+#undef FTRACE_ENTRY_PACKED
+#define FTRACE_ENTRY_PACKED(call, struct_name, id, tstruct, print) \
+	FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
+
+#include "trace_entries.h"
+
+#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_FUNCTION_TRACER)
+int perf_ftrace_event_register(struct trace_event_call *call,
+			       enum trace_reg type, void *data);
+#else
+#define perf_ftrace_event_register NULL
+#endif
+
+#ifdef CONFIG_FTRACE_SYSCALLS
+void init_ftrace_syscalls(void);
+const char *get_syscall_name(int syscall);
+#else
+static inline void init_ftrace_syscalls(void) { }
+static inline const char *get_syscall_name(int syscall)
+{
+	return NULL;
+}
+#endif
+
+#ifdef CONFIG_EVENT_TRACING
+void trace_event_init(void);
+void trace_event_eval_update(struct trace_eval_map **map, int len);
+/* Used from boot time tracer */
+extern int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set);
+extern int trigger_process_regex(struct trace_event_file *file, char *buff);
+#else
+static inline void __init trace_event_init(void) { }
+static inline void trace_event_eval_update(struct trace_eval_map **map, int len) { }
+#endif
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+void tracing_snapshot_instance(struct trace_array *tr);
+int tracing_alloc_snapshot_instance(struct trace_array *tr);
+#else
+static inline void tracing_snapshot_instance(struct trace_array *tr) { }
+static inline int tracing_alloc_snapshot_instance(struct trace_array *tr)
+{
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_PREEMPT_TRACER
+void tracer_preempt_on(unsigned long a0, unsigned long a1);
+void tracer_preempt_off(unsigned long a0, unsigned long a1);
+#else
+static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { }
+static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) { }
+#endif
+#ifdef CONFIG_IRQSOFF_TRACER
+void tracer_hardirqs_on(unsigned long a0, unsigned long a1);
+void tracer_hardirqs_off(unsigned long a0, unsigned long a1);
+#else
+static inline void tracer_hardirqs_on(unsigned long a0, unsigned long a1) { }
+static inline void tracer_hardirqs_off(unsigned long a0, unsigned long a1) { }
+#endif
+
+extern struct trace_iterator *tracepoint_print_iter;
+
+/*
+ * Reset the state of the trace_iterator so that it can read consumed data.
+ * Normally, the trace_iterator is used for reading the data when it is not
+ * consumed, and must retain state.
+ */
+static __always_inline void trace_iterator_reset(struct trace_iterator *iter)
+{
+	memset_startat(iter, 0, seq);
+	iter->pos = -1;
+}
+
+/* Check the name is good for event/group/fields */
+static inline bool __is_good_name(const char *name, bool hash_ok)
+{
+	if (!isalpha(*name) && *name != '_' && (!hash_ok || *name != '-'))
+		return false;
+	while (*++name != '\0') {
+		if (!isalpha(*name) && !isdigit(*name) && *name != '_' &&
+		    (!hash_ok || *name != '-'))
+			return false;
+	}
+	return true;
+}
+
+/* Check the name is good for event/group/fields */
+static inline bool is_good_name(const char *name)
+{
+	return __is_good_name(name, false);
+}
+
+/* Check the name is good for system */
+static inline bool is_good_system_name(const char *name)
+{
+	return __is_good_name(name, true);
+}
+
+/* Convert certain expected symbols into '_' when generating event names */
+static inline void sanitize_event_name(char *name)
+{
+	while (*name++ != '\0')
+		if (*name == ':' || *name == '.')
+			*name = '_';
+}
+
+/*
+ * This is a generic way to read and write a u64 value from a file in tracefs.
+ *
+ * The value is stored on the variable pointed by *val. The value needs
+ * to be at least *min and at most *max. The write is protected by an
+ * existing *lock.
+ */
+struct trace_min_max_param {
+	struct mutex	*lock;
+	u64		*val;
+	u64		*min;
+	u64		*max;
+};
+
+#define U64_STR_SIZE		24	/* 20 digits max */
+
+extern const struct file_operations trace_min_max_fops;
+
+#ifdef CONFIG_RV
+extern int rv_init_interface(void);
+#else
+static inline int rv_init_interface(void)
+{
+	return 0;
+}
+#endif
+
+#endif /* _LINUX_KERNEL_TRACE_H */
diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c
new file mode 100644
index 000000000..54d5fa35c
--- /dev/null
+++ b/kernel/trace/trace_benchmark.c
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/trace_clock.h>
+
+#define CREATE_TRACE_POINTS
+#include "trace_benchmark.h"
+
+static struct task_struct *bm_event_thread;
+
+static char bm_str[BENCHMARK_EVENT_STRLEN] = "START";
+
+static u64 bm_total;
+static u64 bm_totalsq;
+static u64 bm_last;
+static u64 bm_max;
+static u64 bm_min;
+static u64 bm_first;
+static u64 bm_cnt;
+static u64 bm_stddev;
+static unsigned int bm_avg;
+static unsigned int bm_std;
+
+static bool ok_to_run;
+
+/*
+ * This gets called in a loop recording the time it took to write
+ * the tracepoint. What it writes is the time statistics of the last
+ * tracepoint write. As there is nothing to write the first time
+ * it simply writes "START". As the first write is cold cache and
+ * the rest is hot, we save off that time in bm_first and it is
+ * reported as "first", which is shown in the second write to the
+ * tracepoint. The "first" field is written within the statics from
+ * then on but never changes.
+ */
+static void trace_do_benchmark(void)
+{
+	u64 start;
+	u64 stop;
+	u64 delta;
+	u64 stddev;
+	u64 seed;
+	u64 last_seed;
+	unsigned int avg;
+	unsigned int std = 0;
+
+	/* Only run if the tracepoint is actually active */
+	if (!trace_benchmark_event_enabled() || !tracing_is_on())
+		return;
+
+	local_irq_disable();
+	start = trace_clock_local();
+	trace_benchmark_event(bm_str, bm_last);
+	stop = trace_clock_local();
+	local_irq_enable();
+
+	bm_cnt++;
+
+	delta = stop - start;
+
+	/*
+	 * The first read is cold cached, keep it separate from the
+	 * other calculations.
+	 */
+	if (bm_cnt == 1) {
+		bm_first = delta;
+		scnprintf(bm_str, BENCHMARK_EVENT_STRLEN,
+			  "first=%llu [COLD CACHED]", bm_first);
+		return;
+	}
+
+	bm_last = delta;
+
+	if (delta > bm_max)
+		bm_max = delta;
+	if (!bm_min || delta < bm_min)
+		bm_min = delta;
+
+	/*
+	 * When bm_cnt is greater than UINT_MAX, it breaks the statistics
+	 * accounting. Freeze the statistics when that happens.
+	 * We should have enough data for the avg and stddev anyway.
+	 */
+	if (bm_cnt > UINT_MAX) {
+		scnprintf(bm_str, BENCHMARK_EVENT_STRLEN,
+		    "last=%llu first=%llu max=%llu min=%llu ** avg=%u std=%d std^2=%lld",
+			  bm_last, bm_first, bm_max, bm_min, bm_avg, bm_std, bm_stddev);
+		return;
+	}
+
+	bm_total += delta;
+	bm_totalsq += delta * delta;
+
+
+	if (bm_cnt > 1) {
+		/*
+		 * Apply Welford's method to calculate standard deviation:
+		 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
+		 */
+		stddev = (u64)bm_cnt * bm_totalsq - bm_total * bm_total;
+		do_div(stddev, (u32)bm_cnt);
+		do_div(stddev, (u32)bm_cnt - 1);
+	} else
+		stddev = 0;
+
+	delta = bm_total;
+	do_div(delta, bm_cnt);
+	avg = delta;
+
+	if (stddev > 0) {
+		int i = 0;
+		/*
+		 * stddev is the square of standard deviation but
+		 * we want the actually number. Use the average
+		 * as our seed to find the std.
+		 *
+		 * The next try is:
+		 *  x = (x + N/x) / 2
+		 *
+		 * Where N is the squared number to find the square
+		 * root of.
+		 */
+		seed = avg;
+		do {
+			last_seed = seed;
+			seed = stddev;
+			if (!last_seed)
+				break;
+			do_div(seed, last_seed);
+			seed += last_seed;
+			do_div(seed, 2);
+		} while (i++ < 10 && last_seed != seed);
+
+		std = seed;
+	}
+
+	scnprintf(bm_str, BENCHMARK_EVENT_STRLEN,
+		  "last=%llu first=%llu max=%llu min=%llu avg=%u std=%d std^2=%lld",
+		  bm_last, bm_first, bm_max, bm_min, avg, std, stddev);
+
+	bm_std = std;
+	bm_avg = avg;
+	bm_stddev = stddev;
+}
+
+static int benchmark_event_kthread(void *arg)
+{
+	/* sleep a bit to make sure the tracepoint gets activated */
+	msleep(100);
+
+	while (!kthread_should_stop()) {
+
+		trace_do_benchmark();
+
+		/*
+		 * We don't go to sleep, but let others run as well.
+		 * This is basically a "yield()" to let any task that
+		 * wants to run, schedule in, but if the CPU is idle,
+		 * we'll keep burning cycles.
+		 *
+		 * Note the tasks_rcu_qs() version of cond_resched() will
+		 * notify synchronize_rcu_tasks() that this thread has
+		 * passed a quiescent state for rcu_tasks. Otherwise
+		 * this thread will never voluntarily schedule which would
+		 * block synchronize_rcu_tasks() indefinitely.
+		 */
+		cond_resched_tasks_rcu_qs();
+	}
+
+	return 0;
+}
+
+/*
+ * When the benchmark tracepoint is enabled, it calls this
+ * function and the thread that calls the tracepoint is created.
+ */
+int trace_benchmark_reg(void)
+{
+	if (!ok_to_run) {
+		pr_warn("trace benchmark cannot be started via kernel command line\n");
+		return -EBUSY;
+	}
+
+	bm_event_thread = kthread_run(benchmark_event_kthread,
+				      NULL, "event_benchmark");
+	if (IS_ERR(bm_event_thread)) {
+		pr_warn("trace benchmark failed to create kernel thread\n");
+		return PTR_ERR(bm_event_thread);
+	}
+
+	return 0;
+}
+
+/*
+ * When the benchmark tracepoint is disabled, it calls this
+ * function and the thread that calls the tracepoint is deleted
+ * and all the numbers are reset.
+ */
+void trace_benchmark_unreg(void)
+{
+	if (!bm_event_thread)
+		return;
+
+	kthread_stop(bm_event_thread);
+	bm_event_thread = NULL;
+
+	strcpy(bm_str, "START");
+	bm_total = 0;
+	bm_totalsq = 0;
+	bm_last = 0;
+	bm_max = 0;
+	bm_min = 0;
+	bm_cnt = 0;
+	/* These don't need to be reset but reset them anyway */
+	bm_first = 0;
+	bm_std = 0;
+	bm_avg = 0;
+	bm_stddev = 0;
+}
+
+static __init int ok_to_run_trace_benchmark(void)
+{
+	ok_to_run = true;
+
+	return 0;
+}
+
+early_initcall(ok_to_run_trace_benchmark);
diff --git a/kernel/trace/trace_benchmark.h b/kernel/trace/trace_benchmark.h
new file mode 100644
index 000000000..c3e91060d
--- /dev/null
+++ b/kernel/trace/trace_benchmark.h
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM benchmark
+
+#if !defined(_TRACE_BENCHMARK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_BENCHMARK_H
+
+#include <linux/tracepoint.h>
+
+extern int trace_benchmark_reg(void);
+extern void trace_benchmark_unreg(void);
+
+#define BENCHMARK_EVENT_STRLEN		128
+
+TRACE_EVENT_FN(benchmark_event,
+
+	TP_PROTO(const char *str, u64 delta),
+
+	TP_ARGS(str, delta),
+
+	TP_STRUCT__entry(
+		__array(	char,	str,	BENCHMARK_EVENT_STRLEN	)
+		__field(	u64,	delta)
+	),
+
+	TP_fast_assign(
+		memcpy(__entry->str, str, BENCHMARK_EVENT_STRLEN);
+		__entry->delta = delta;
+	),
+
+	TP_printk("%s delta=%llu", __entry->str, __entry->delta),
+
+	trace_benchmark_reg, trace_benchmark_unreg
+);
+
+#endif /* _TRACE_BENCHMARK_H */
+
+#undef TRACE_INCLUDE_FILE
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE trace_benchmark
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
new file mode 100644
index 000000000..778200dd8
--- /dev/null
+++ b/kernel/trace/trace_boot.c
@@ -0,0 +1,671 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_boot.c
+ * Tracing kernel boot-time
+ */
+
+#define pr_fmt(fmt)	"trace_boot: " fmt
+
+#include <linux/bootconfig.h>
+#include <linux/cpumask.h>
+#include <linux/ftrace.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/trace.h>
+#include <linux/trace_events.h>
+
+#include "trace.h"
+
+#define MAX_BUF_LEN 256
+
+static void __init
+trace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node)
+{
+	struct xbc_node *anode;
+	const char *p;
+	char buf[MAX_BUF_LEN];
+	unsigned long v = 0;
+
+	/* Common ftrace options */
+	xbc_node_for_each_array_value(node, "options", anode, p) {
+		if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
+			pr_err("String is too long: %s\n", p);
+			continue;
+		}
+
+		if (trace_set_options(tr, buf) < 0)
+			pr_err("Failed to set option: %s\n", buf);
+	}
+
+	p = xbc_node_find_value(node, "tracing_on", NULL);
+	if (p && *p != '\0') {
+		if (kstrtoul(p, 10, &v))
+			pr_err("Failed to set tracing on: %s\n", p);
+		if (v)
+			tracer_tracing_on(tr);
+		else
+			tracer_tracing_off(tr);
+	}
+
+	p = xbc_node_find_value(node, "trace_clock", NULL);
+	if (p && *p != '\0') {
+		if (tracing_set_clock(tr, p) < 0)
+			pr_err("Failed to set trace clock: %s\n", p);
+	}
+
+	p = xbc_node_find_value(node, "buffer_size", NULL);
+	if (p && *p != '\0') {
+		v = memparse(p, NULL);
+		if (v < PAGE_SIZE)
+			pr_err("Buffer size is too small: %s\n", p);
+		if (tracing_resize_ring_buffer(tr, v, RING_BUFFER_ALL_CPUS) < 0)
+			pr_err("Failed to resize trace buffer to %s\n", p);
+	}
+
+	p = xbc_node_find_value(node, "cpumask", NULL);
+	if (p && *p != '\0') {
+		cpumask_var_t new_mask;
+
+		if (alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
+			if (cpumask_parse(p, new_mask) < 0 ||
+			    tracing_set_cpumask(tr, new_mask) < 0)
+				pr_err("Failed to set new CPU mask %s\n", p);
+			free_cpumask_var(new_mask);
+		}
+	}
+}
+
+#ifdef CONFIG_EVENT_TRACING
+static void __init
+trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node)
+{
+	struct xbc_node *anode;
+	char buf[MAX_BUF_LEN];
+	const char *p;
+
+	xbc_node_for_each_array_value(node, "events", anode, p) {
+		if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
+			pr_err("String is too long: %s\n", p);
+			continue;
+		}
+
+		if (ftrace_set_clr_event(tr, buf, 1) < 0)
+			pr_err("Failed to enable event: %s\n", p);
+	}
+}
+
+#ifdef CONFIG_KPROBE_EVENTS
+static int __init
+trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
+{
+	struct dynevent_cmd cmd;
+	struct xbc_node *anode;
+	char buf[MAX_BUF_LEN];
+	const char *val;
+	int ret = 0;
+
+	xbc_node_for_each_array_value(node, "probes", anode, val) {
+		kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
+
+		ret = kprobe_event_gen_cmd_start(&cmd, event, val);
+		if (ret) {
+			pr_err("Failed to generate probe: %s\n", buf);
+			break;
+		}
+
+		ret = kprobe_event_gen_cmd_end(&cmd);
+		if (ret) {
+			pr_err("Failed to add probe: %s\n", buf);
+			break;
+		}
+	}
+
+	return ret;
+}
+#else
+static inline int __init
+trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
+{
+	pr_err("Kprobe event is not supported.\n");
+	return -ENOTSUPP;
+}
+#endif
+
+#ifdef CONFIG_SYNTH_EVENTS
+static int __init
+trace_boot_add_synth_event(struct xbc_node *node, const char *event)
+{
+	struct dynevent_cmd cmd;
+	struct xbc_node *anode;
+	char buf[MAX_BUF_LEN];
+	const char *p;
+	int ret;
+
+	synth_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
+
+	ret = synth_event_gen_cmd_start(&cmd, event, NULL);
+	if (ret)
+		return ret;
+
+	xbc_node_for_each_array_value(node, "fields", anode, p) {
+		ret = synth_event_add_field_str(&cmd, p);
+		if (ret)
+			return ret;
+	}
+
+	ret = synth_event_gen_cmd_end(&cmd);
+	if (ret < 0)
+		pr_err("Failed to add synthetic event: %s\n", buf);
+
+	return ret;
+}
+#else
+static inline int __init
+trace_boot_add_synth_event(struct xbc_node *node, const char *event)
+{
+	pr_err("Synthetic event is not supported.\n");
+	return -ENOTSUPP;
+}
+#endif
+
+#ifdef CONFIG_HIST_TRIGGERS
+static int __init __printf(3, 4)
+append_printf(char **bufp, char *end, const char *fmt, ...)
+{
+	va_list args;
+	int ret;
+
+	if (*bufp == end)
+		return -ENOSPC;
+
+	va_start(args, fmt);
+	ret = vsnprintf(*bufp, end - *bufp, fmt, args);
+	if (ret < end - *bufp) {
+		*bufp += ret;
+	} else {
+		*bufp = end;
+		ret = -ERANGE;
+	}
+	va_end(args);
+
+	return ret;
+}
+
+static int __init
+append_str_nospace(char **bufp, char *end, const char *str)
+{
+	char *p = *bufp;
+	int len;
+
+	while (p < end - 1 && *str != '\0') {
+		if (!isspace(*str))
+			*(p++) = *str;
+		str++;
+	}
+	*p = '\0';
+	if (p == end - 1) {
+		*bufp = end;
+		return -ENOSPC;
+	}
+	len = p - *bufp;
+	*bufp = p;
+	return (int)len;
+}
+
+static int __init
+trace_boot_hist_add_array(struct xbc_node *hnode, char **bufp,
+			  char *end, const char *key)
+{
+	struct xbc_node *anode;
+	const char *p;
+	char sep;
+
+	p = xbc_node_find_value(hnode, key, &anode);
+	if (p) {
+		if (!anode) {
+			pr_err("hist.%s requires value(s).\n", key);
+			return -EINVAL;
+		}
+
+		append_printf(bufp, end, ":%s", key);
+		sep = '=';
+		xbc_array_for_each_value(anode, p) {
+			append_printf(bufp, end, "%c%s", sep, p);
+			if (sep == '=')
+				sep = ',';
+		}
+	} else
+		return -ENOENT;
+
+	return 0;
+}
+
+static int __init
+trace_boot_hist_add_one_handler(struct xbc_node *hnode, char **bufp,
+				char *end, const char *handler,
+				const char *param)
+{
+	struct xbc_node *knode, *anode;
+	const char *p;
+	char sep;
+
+	/* Compose 'handler' parameter */
+	p = xbc_node_find_value(hnode, param, NULL);
+	if (!p) {
+		pr_err("hist.%s requires '%s' option.\n",
+		       xbc_node_get_data(hnode), param);
+		return -EINVAL;
+	}
+	append_printf(bufp, end, ":%s(%s)", handler, p);
+
+	/* Compose 'action' parameter */
+	knode = xbc_node_find_subkey(hnode, "trace");
+	if (!knode)
+		knode = xbc_node_find_subkey(hnode, "save");
+
+	if (knode) {
+		anode = xbc_node_get_child(knode);
+		if (!anode || !xbc_node_is_value(anode)) {
+			pr_err("hist.%s.%s requires value(s).\n",
+			       xbc_node_get_data(hnode),
+			       xbc_node_get_data(knode));
+			return -EINVAL;
+		}
+
+		append_printf(bufp, end, ".%s", xbc_node_get_data(knode));
+		sep = '(';
+		xbc_array_for_each_value(anode, p) {
+			append_printf(bufp, end, "%c%s", sep, p);
+			if (sep == '(')
+				sep = ',';
+		}
+		append_printf(bufp, end, ")");
+	} else if (xbc_node_find_subkey(hnode, "snapshot")) {
+		append_printf(bufp, end, ".snapshot()");
+	} else {
+		pr_err("hist.%s requires an action.\n",
+		       xbc_node_get_data(hnode));
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int __init
+trace_boot_hist_add_handlers(struct xbc_node *hnode, char **bufp,
+			     char *end, const char *param)
+{
+	struct xbc_node *node;
+	const char *p, *handler;
+	int ret = 0;
+
+	handler = xbc_node_get_data(hnode);
+
+	xbc_node_for_each_subkey(hnode, node) {
+		p = xbc_node_get_data(node);
+		if (!isdigit(p[0]))
+			continue;
+		/* All digit started node should be instances. */
+		ret = trace_boot_hist_add_one_handler(node, bufp, end, handler, param);
+		if (ret < 0)
+			break;
+	}
+
+	if (xbc_node_find_subkey(hnode, param))
+		ret = trace_boot_hist_add_one_handler(hnode, bufp, end, handler, param);
+
+	return ret;
+}
+
+/*
+ * Histogram boottime tracing syntax.
+ *
+ * ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist[.N] {
+ *	keys = <KEY>[,...]
+ *	values = <VAL>[,...]
+ *	sort = <SORT-KEY>[,...]
+ *	size = <ENTRIES>
+ *	name = <HISTNAME>
+ *	var { <VAR> = <EXPR> ... }
+ *	pause|continue|clear
+ *	onmax|onchange[.N] { var = <VAR>; <ACTION> [= <PARAM>] }
+ *	onmatch[.N] { event = <EVENT>; <ACTION> [= <PARAM>] }
+ *	filter = <FILTER>
+ * }
+ *
+ * Where <ACTION> are;
+ *
+ *	trace = <EVENT>, <ARG1>[, ...]
+ *	save = <ARG1>[, ...]
+ *	snapshot
+ */
+static int __init
+trace_boot_compose_hist_cmd(struct xbc_node *hnode, char *buf, size_t size)
+{
+	struct xbc_node *node, *knode;
+	char *end = buf + size;
+	const char *p;
+	int ret = 0;
+
+	append_printf(&buf, end, "hist");
+
+	ret = trace_boot_hist_add_array(hnode, &buf, end, "keys");
+	if (ret < 0) {
+		if (ret == -ENOENT)
+			pr_err("hist requires keys.\n");
+		return -EINVAL;
+	}
+
+	ret = trace_boot_hist_add_array(hnode, &buf, end, "values");
+	if (ret == -EINVAL)
+		return ret;
+	ret = trace_boot_hist_add_array(hnode, &buf, end, "sort");
+	if (ret == -EINVAL)
+		return ret;
+
+	p = xbc_node_find_value(hnode, "size", NULL);
+	if (p)
+		append_printf(&buf, end, ":size=%s", p);
+
+	p = xbc_node_find_value(hnode, "name", NULL);
+	if (p)
+		append_printf(&buf, end, ":name=%s", p);
+
+	node = xbc_node_find_subkey(hnode, "var");
+	if (node) {
+		xbc_node_for_each_key_value(node, knode, p) {
+			/* Expression must not include spaces. */
+			append_printf(&buf, end, ":%s=",
+				      xbc_node_get_data(knode));
+			append_str_nospace(&buf, end, p);
+		}
+	}
+
+	/* Histogram control attributes (mutual exclusive) */
+	if (xbc_node_find_value(hnode, "pause", NULL))
+		append_printf(&buf, end, ":pause");
+	else if (xbc_node_find_value(hnode, "continue", NULL))
+		append_printf(&buf, end, ":continue");
+	else if (xbc_node_find_value(hnode, "clear", NULL))
+		append_printf(&buf, end, ":clear");
+
+	/* Histogram handler and actions */
+	node = xbc_node_find_subkey(hnode, "onmax");
+	if (node && trace_boot_hist_add_handlers(node, &buf, end, "var") < 0)
+		return -EINVAL;
+	node = xbc_node_find_subkey(hnode, "onchange");
+	if (node && trace_boot_hist_add_handlers(node, &buf, end, "var") < 0)
+		return -EINVAL;
+	node = xbc_node_find_subkey(hnode, "onmatch");
+	if (node && trace_boot_hist_add_handlers(node, &buf, end, "event") < 0)
+		return -EINVAL;
+
+	p = xbc_node_find_value(hnode, "filter", NULL);
+	if (p)
+		append_printf(&buf, end, " if %s", p);
+
+	if (buf == end) {
+		pr_err("hist exceeds the max command length.\n");
+		return -E2BIG;
+	}
+
+	return 0;
+}
+
+static void __init
+trace_boot_init_histograms(struct trace_event_file *file,
+			   struct xbc_node *hnode, char *buf, size_t size)
+{
+	struct xbc_node *node;
+	const char *p;
+	char *tmp;
+
+	xbc_node_for_each_subkey(hnode, node) {
+		p = xbc_node_get_data(node);
+		if (!isdigit(p[0]))
+			continue;
+		/* All digit started node should be instances. */
+		if (trace_boot_compose_hist_cmd(node, buf, size) == 0) {
+			tmp = kstrdup(buf, GFP_KERNEL);
+			if (!tmp)
+				return;
+			if (trigger_process_regex(file, buf) < 0)
+				pr_err("Failed to apply hist trigger: %s\n", tmp);
+			kfree(tmp);
+		}
+	}
+
+	if (xbc_node_find_subkey(hnode, "keys")) {
+		if (trace_boot_compose_hist_cmd(hnode, buf, size) == 0) {
+			tmp = kstrdup(buf, GFP_KERNEL);
+			if (!tmp)
+				return;
+			if (trigger_process_regex(file, buf) < 0)
+				pr_err("Failed to apply hist trigger: %s\n", tmp);
+			kfree(tmp);
+		}
+	}
+}
+#else
+static void __init
+trace_boot_init_histograms(struct trace_event_file *file,
+			   struct xbc_node *hnode, char *buf, size_t size)
+{
+	/* do nothing */
+}
+#endif
+
+static void __init
+trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
+			  struct xbc_node *enode)
+{
+	struct trace_event_file *file;
+	struct xbc_node *anode;
+	char buf[MAX_BUF_LEN];
+	const char *p, *group, *event;
+
+	group = xbc_node_get_data(gnode);
+	event = xbc_node_get_data(enode);
+
+	if (!strcmp(group, "kprobes"))
+		if (trace_boot_add_kprobe_event(enode, event) < 0)
+			return;
+	if (!strcmp(group, "synthetic"))
+		if (trace_boot_add_synth_event(enode, event) < 0)
+			return;
+
+	mutex_lock(&event_mutex);
+	file = find_event_file(tr, group, event);
+	if (!file) {
+		pr_err("Failed to find event: %s:%s\n", group, event);
+		goto out;
+	}
+
+	p = xbc_node_find_value(enode, "filter", NULL);
+	if (p && *p != '\0') {
+		if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
+			pr_err("filter string is too long: %s\n", p);
+		else if (apply_event_filter(file, buf) < 0)
+			pr_err("Failed to apply filter: %s\n", buf);
+	}
+
+	if (IS_ENABLED(CONFIG_HIST_TRIGGERS)) {
+		xbc_node_for_each_array_value(enode, "actions", anode, p) {
+			if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
+				pr_err("action string is too long: %s\n", p);
+			else if (trigger_process_regex(file, buf) < 0)
+				pr_err("Failed to apply an action: %s\n", p);
+		}
+		anode = xbc_node_find_subkey(enode, "hist");
+		if (anode)
+			trace_boot_init_histograms(file, anode, buf, ARRAY_SIZE(buf));
+	} else if (xbc_node_find_value(enode, "actions", NULL))
+		pr_err("Failed to apply event actions because CONFIG_HIST_TRIGGERS is not set.\n");
+
+	if (xbc_node_find_value(enode, "enable", NULL)) {
+		if (trace_event_enable_disable(file, 1, 0) < 0)
+			pr_err("Failed to enable event node: %s:%s\n",
+				group, event);
+	}
+out:
+	mutex_unlock(&event_mutex);
+}
+
+static void __init
+trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
+{
+	struct xbc_node *gnode, *enode;
+	bool enable, enable_all = false;
+	const char *data;
+
+	node = xbc_node_find_subkey(node, "event");
+	if (!node)
+		return;
+	/* per-event key starts with "event.GROUP.EVENT" */
+	xbc_node_for_each_subkey(node, gnode) {
+		data = xbc_node_get_data(gnode);
+		if (!strcmp(data, "enable")) {
+			enable_all = true;
+			continue;
+		}
+		enable = false;
+		xbc_node_for_each_subkey(gnode, enode) {
+			data = xbc_node_get_data(enode);
+			if (!strcmp(data, "enable")) {
+				enable = true;
+				continue;
+			}
+			trace_boot_init_one_event(tr, gnode, enode);
+		}
+		/* Event enablement must be done after event settings */
+		if (enable) {
+			data = xbc_node_get_data(gnode);
+			trace_array_set_clr_event(tr, data, NULL, true);
+		}
+	}
+	/* Ditto */
+	if (enable_all)
+		trace_array_set_clr_event(tr, NULL, NULL, true);
+}
+#else
+#define trace_boot_enable_events(tr, node) do {} while (0)
+#define trace_boot_init_events(tr, node) do {} while (0)
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+static void __init
+trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
+{
+	struct xbc_node *anode;
+	const char *p;
+	char *q;
+
+	xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
+		q = kstrdup(p, GFP_KERNEL);
+		if (!q)
+			return;
+		if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
+			pr_err("Failed to add %s to ftrace filter\n", p);
+		else
+			ftrace_filter_param = true;
+		kfree(q);
+	}
+	xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
+		q = kstrdup(p, GFP_KERNEL);
+		if (!q)
+			return;
+		if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
+			pr_err("Failed to add %s to ftrace filter\n", p);
+		else
+			ftrace_filter_param = true;
+		kfree(q);
+	}
+}
+#else
+#define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
+#endif
+
+static void __init
+trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
+{
+	const char *p;
+
+	trace_boot_set_ftrace_filter(tr, node);
+
+	p = xbc_node_find_value(node, "tracer", NULL);
+	if (p && *p != '\0') {
+		if (tracing_set_tracer(tr, p) < 0)
+			pr_err("Failed to set given tracer: %s\n", p);
+	}
+
+	/* Since tracer can free snapshot buffer, allocate snapshot here.*/
+	if (xbc_node_find_value(node, "alloc_snapshot", NULL)) {
+		if (tracing_alloc_snapshot_instance(tr) < 0)
+			pr_err("Failed to allocate snapshot buffer\n");
+	}
+}
+
+static void __init
+trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
+{
+	trace_boot_set_instance_options(tr, node);
+	trace_boot_init_events(tr, node);
+	trace_boot_enable_events(tr, node);
+	trace_boot_enable_tracer(tr, node);
+}
+
+static void __init
+trace_boot_init_instances(struct xbc_node *node)
+{
+	struct xbc_node *inode;
+	struct trace_array *tr;
+	const char *p;
+
+	node = xbc_node_find_subkey(node, "instance");
+	if (!node)
+		return;
+
+	xbc_node_for_each_subkey(node, inode) {
+		p = xbc_node_get_data(inode);
+		if (!p || *p == '\0')
+			continue;
+
+		tr = trace_array_get_by_name(p);
+		if (!tr) {
+			pr_err("Failed to get trace instance %s\n", p);
+			continue;
+		}
+		trace_boot_init_one_instance(tr, inode);
+		trace_array_put(tr);
+	}
+}
+
+static int __init trace_boot_init(void)
+{
+	struct xbc_node *trace_node;
+	struct trace_array *tr;
+
+	trace_node = xbc_find_node("ftrace");
+	if (!trace_node)
+		return 0;
+
+	tr = top_trace_array();
+	if (!tr)
+		return 0;
+
+	/* Global trace array is also one instance */
+	trace_boot_init_one_instance(tr, trace_node);
+	trace_boot_init_instances(trace_node);
+
+	disable_tracing_selftest("running boot-time tracing");
+
+	return 0;
+}
+/*
+ * Start tracing at the end of core-initcall, so that it starts tracing
+ * from the beginning of postcore_initcall.
+ */
+core_initcall_sync(trace_boot_init);
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
new file mode 100644
index 000000000..e47fdb4c9
--- /dev/null
+++ b/kernel/trace/trace_branch.c
@@ -0,0 +1,455 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * unlikely profiler
+ *
+ * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
+ */
+#include <linux/kallsyms.h>
+#include <linux/seq_file.h>
+#include <linux/spinlock.h>
+#include <linux/irqflags.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+#include <linux/hash.h>
+#include <linux/fs.h>
+#include <asm/local.h>
+
+#include "trace.h"
+#include "trace_stat.h"
+#include "trace_output.h"
+
+#ifdef CONFIG_BRANCH_TRACER
+
+static struct tracer branch_trace;
+static int branch_tracing_enabled __read_mostly;
+static DEFINE_MUTEX(branch_tracing_mutex);
+
+static struct trace_array *branch_tracer;
+
+static void
+probe_likely_condition(struct ftrace_likely_data *f, int val, int expect)
+{
+	struct trace_event_call *call = &event_branch;
+	struct trace_array *tr = branch_tracer;
+	struct trace_buffer *buffer;
+	struct trace_array_cpu *data;
+	struct ring_buffer_event *event;
+	struct trace_branch *entry;
+	unsigned long flags;
+	unsigned int trace_ctx;
+	const char *p;
+
+	if (current->trace_recursion & TRACE_BRANCH_BIT)
+		return;
+
+	/*
+	 * I would love to save just the ftrace_likely_data pointer, but
+	 * this code can also be used by modules. Ugly things can happen
+	 * if the module is unloaded, and then we go and read the
+	 * pointer.  This is slower, but much safer.
+	 */
+
+	if (unlikely(!tr))
+		return;
+
+	raw_local_irq_save(flags);
+	current->trace_recursion |= TRACE_BRANCH_BIT;
+	data = this_cpu_ptr(tr->array_buffer.data);
+	if (atomic_read(&data->disabled))
+		goto out;
+
+	trace_ctx = tracing_gen_ctx_flags(flags);
+	buffer = tr->array_buffer.buffer;
+	event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH,
+					  sizeof(*entry), trace_ctx);
+	if (!event)
+		goto out;
+
+	entry	= ring_buffer_event_data(event);
+
+	/* Strip off the path, only save the file */
+	p = f->data.file + strlen(f->data.file);
+	while (p >= f->data.file && *p != '/')
+		p--;
+	p++;
+
+	strncpy(entry->func, f->data.func, TRACE_FUNC_SIZE);
+	strncpy(entry->file, p, TRACE_FILE_SIZE);
+	entry->func[TRACE_FUNC_SIZE] = 0;
+	entry->file[TRACE_FILE_SIZE] = 0;
+	entry->constant = f->constant;
+	entry->line = f->data.line;
+	entry->correct = val == expect;
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit_nostack(buffer, event);
+
+ out:
+	current->trace_recursion &= ~TRACE_BRANCH_BIT;
+	raw_local_irq_restore(flags);
+}
+
+static inline
+void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
+{
+	if (!branch_tracing_enabled)
+		return;
+
+	probe_likely_condition(f, val, expect);
+}
+
+int enable_branch_tracing(struct trace_array *tr)
+{
+	mutex_lock(&branch_tracing_mutex);
+	branch_tracer = tr;
+	/*
+	 * Must be seen before enabling. The reader is a condition
+	 * where we do not need a matching rmb()
+	 */
+	smp_wmb();
+	branch_tracing_enabled++;
+	mutex_unlock(&branch_tracing_mutex);
+
+	return 0;
+}
+
+void disable_branch_tracing(void)
+{
+	mutex_lock(&branch_tracing_mutex);
+
+	if (!branch_tracing_enabled)
+		goto out_unlock;
+
+	branch_tracing_enabled--;
+
+ out_unlock:
+	mutex_unlock(&branch_tracing_mutex);
+}
+
+static int branch_trace_init(struct trace_array *tr)
+{
+	return enable_branch_tracing(tr);
+}
+
+static void branch_trace_reset(struct trace_array *tr)
+{
+	disable_branch_tracing();
+}
+
+static enum print_line_t trace_branch_print(struct trace_iterator *iter,
+					    int flags, struct trace_event *event)
+{
+	struct trace_branch *field;
+
+	trace_assign_type(field, iter->ent);
+
+	trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
+			 field->correct ? "  ok  " : " MISS ",
+			 field->func,
+			 field->file,
+			 field->line);
+
+	return trace_handle_return(&iter->seq);
+}
+
+static void branch_print_header(struct seq_file *s)
+{
+	seq_puts(s, "#           TASK-PID    CPU#    TIMESTAMP  CORRECT"
+		    "  FUNC:FILE:LINE\n"
+		    "#              | |       |          |         |   "
+		    "    |\n");
+}
+
+static struct trace_event_functions trace_branch_funcs = {
+	.trace		= trace_branch_print,
+};
+
+static struct trace_event trace_branch_event = {
+	.type		= TRACE_BRANCH,
+	.funcs		= &trace_branch_funcs,
+};
+
+static struct tracer branch_trace __read_mostly =
+{
+	.name		= "branch",
+	.init		= branch_trace_init,
+	.reset		= branch_trace_reset,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest	= trace_selftest_startup_branch,
+#endif /* CONFIG_FTRACE_SELFTEST */
+	.print_header	= branch_print_header,
+};
+
+__init static int init_branch_tracer(void)
+{
+	int ret;
+
+	ret = register_trace_event(&trace_branch_event);
+	if (!ret) {
+		printk(KERN_WARNING "Warning: could not register "
+				    "branch events\n");
+		return 1;
+	}
+	return register_tracer(&branch_trace);
+}
+core_initcall(init_branch_tracer);
+
+#else
+static inline
+void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
+{
+}
+#endif /* CONFIG_BRANCH_TRACER */
+
+void ftrace_likely_update(struct ftrace_likely_data *f, int val,
+			  int expect, int is_constant)
+{
+	unsigned long flags = user_access_save();
+
+	/* A constant is always correct */
+	if (is_constant) {
+		f->constant++;
+		val = expect;
+	}
+	/*
+	 * I would love to have a trace point here instead, but the
+	 * trace point code is so inundated with unlikely and likely
+	 * conditions that the recursive nightmare that exists is too
+	 * much to try to get working. At least for now.
+	 */
+	trace_likely_condition(f, val, expect);
+
+	/* FIXME: Make this atomic! */
+	if (val == expect)
+		f->data.correct++;
+	else
+		f->data.incorrect++;
+
+	user_access_restore(flags);
+}
+EXPORT_SYMBOL(ftrace_likely_update);
+
+extern unsigned long __start_annotated_branch_profile[];
+extern unsigned long __stop_annotated_branch_profile[];
+
+static int annotated_branch_stat_headers(struct seq_file *m)
+{
+	seq_puts(m, " correct incorrect  % "
+		    "       Function                "
+		    "  File              Line\n"
+		    " ------- ---------  - "
+		    "       --------                "
+		    "  ----              ----\n");
+	return 0;
+}
+
+static inline long get_incorrect_percent(const struct ftrace_branch_data *p)
+{
+	long percent;
+
+	if (p->correct) {
+		percent = p->incorrect * 100;
+		percent /= p->correct + p->incorrect;
+	} else
+		percent = p->incorrect ? 100 : -1;
+
+	return percent;
+}
+
+static const char *branch_stat_process_file(struct ftrace_branch_data *p)
+{
+	const char *f;
+
+	/* Only print the file, not the path */
+	f = p->file + strlen(p->file);
+	while (f >= p->file && *f != '/')
+		f--;
+	return ++f;
+}
+
+static void branch_stat_show(struct seq_file *m,
+			     struct ftrace_branch_data *p, const char *f)
+{
+	long percent;
+
+	/*
+	 * The miss is overlayed on correct, and hit on incorrect.
+	 */
+	percent = get_incorrect_percent(p);
+
+	if (percent < 0)
+		seq_puts(m, "  X ");
+	else
+		seq_printf(m, "%3ld ", percent);
+
+	seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);
+}
+
+static int branch_stat_show_normal(struct seq_file *m,
+				   struct ftrace_branch_data *p, const char *f)
+{
+	seq_printf(m, "%8lu %8lu ",  p->correct, p->incorrect);
+	branch_stat_show(m, p, f);
+	return 0;
+}
+
+static int annotate_branch_stat_show(struct seq_file *m, void *v)
+{
+	struct ftrace_likely_data *p = v;
+	const char *f;
+	int l;
+
+	f = branch_stat_process_file(&p->data);
+
+	if (!p->constant)
+		return branch_stat_show_normal(m, &p->data, f);
+
+	l = snprintf(NULL, 0, "/%lu", p->constant);
+	l = l > 8 ? 0 : 8 - l;
+
+	seq_printf(m, "%8lu/%lu %*lu ",
+		   p->data.correct, p->constant, l, p->data.incorrect);
+	branch_stat_show(m, &p->data, f);
+	return 0;
+}
+
+static void *annotated_branch_stat_start(struct tracer_stat *trace)
+{
+	return __start_annotated_branch_profile;
+}
+
+static void *
+annotated_branch_stat_next(void *v, int idx)
+{
+	struct ftrace_likely_data *p = v;
+
+	++p;
+
+	if ((void *)p >= (void *)__stop_annotated_branch_profile)
+		return NULL;
+
+	return p;
+}
+
+static int annotated_branch_stat_cmp(const void *p1, const void *p2)
+{
+	const struct ftrace_branch_data *a = p1;
+	const struct ftrace_branch_data *b = p2;
+
+	long percent_a, percent_b;
+
+	percent_a = get_incorrect_percent(a);
+	percent_b = get_incorrect_percent(b);
+
+	if (percent_a < percent_b)
+		return -1;
+	if (percent_a > percent_b)
+		return 1;
+
+	if (a->incorrect < b->incorrect)
+		return -1;
+	if (a->incorrect > b->incorrect)
+		return 1;
+
+	/*
+	 * Since the above shows worse (incorrect) cases
+	 * first, we continue that by showing best (correct)
+	 * cases last.
+	 */
+	if (a->correct > b->correct)
+		return -1;
+	if (a->correct < b->correct)
+		return 1;
+
+	return 0;
+}
+
+static struct tracer_stat annotated_branch_stats = {
+	.name = "branch_annotated",
+	.stat_start = annotated_branch_stat_start,
+	.stat_next = annotated_branch_stat_next,
+	.stat_cmp = annotated_branch_stat_cmp,
+	.stat_headers = annotated_branch_stat_headers,
+	.stat_show = annotate_branch_stat_show
+};
+
+__init static int init_annotated_branch_stats(void)
+{
+	int ret;
+
+	ret = register_stat_tracer(&annotated_branch_stats);
+	if (!ret) {
+		printk(KERN_WARNING "Warning: could not register "
+				    "annotated branches stats\n");
+		return 1;
+	}
+	return 0;
+}
+fs_initcall(init_annotated_branch_stats);
+
+#ifdef CONFIG_PROFILE_ALL_BRANCHES
+
+extern unsigned long __start_branch_profile[];
+extern unsigned long __stop_branch_profile[];
+
+static int all_branch_stat_headers(struct seq_file *m)
+{
+	seq_puts(m, "   miss      hit    % "
+		    "       Function                "
+		    "  File              Line\n"
+		    " ------- ---------  - "
+		    "       --------                "
+		    "  ----              ----\n");
+	return 0;
+}
+
+static void *all_branch_stat_start(struct tracer_stat *trace)
+{
+	return __start_branch_profile;
+}
+
+static void *
+all_branch_stat_next(void *v, int idx)
+{
+	struct ftrace_branch_data *p = v;
+
+	++p;
+
+	if ((void *)p >= (void *)__stop_branch_profile)
+		return NULL;
+
+	return p;
+}
+
+static int all_branch_stat_show(struct seq_file *m, void *v)
+{
+	struct ftrace_branch_data *p = v;
+	const char *f;
+
+	f = branch_stat_process_file(p);
+	return branch_stat_show_normal(m, p, f);
+}
+
+static struct tracer_stat all_branch_stats = {
+	.name = "branch_all",
+	.stat_start = all_branch_stat_start,
+	.stat_next = all_branch_stat_next,
+	.stat_headers = all_branch_stat_headers,
+	.stat_show = all_branch_stat_show
+};
+
+__init static int all_annotated_branch_stats(void)
+{
+	int ret;
+
+	ret = register_stat_tracer(&all_branch_stats);
+	if (!ret) {
+		printk(KERN_WARNING "Warning: could not register "
+				    "all branches stats\n");
+		return 1;
+	}
+	return 0;
+}
+fs_initcall(all_annotated_branch_stats);
+#endif /* CONFIG_PROFILE_ALL_BRANCHES */
diff --git a/kernel/trace/trace_clock.c b/kernel/trace/trace_clock.c
new file mode 100644
index 000000000..4702efb00
--- /dev/null
+++ b/kernel/trace/trace_clock.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * tracing clocks
+ *
+ *  Copyright (C) 2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * Implements 3 trace clock variants, with differing scalability/precision
+ * tradeoffs:
+ *
+ *  -   local: CPU-local trace clock
+ *  -  medium: scalable global clock with some jitter
+ *  -  global: globally monotonic, serialized clock
+ *
+ * Tracer plugins will chose a default from these clocks.
+ */
+#include <linux/spinlock.h>
+#include <linux/irqflags.h>
+#include <linux/hardirq.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/sched.h>
+#include <linux/sched/clock.h>
+#include <linux/ktime.h>
+#include <linux/trace_clock.h>
+
+/*
+ * trace_clock_local(): the simplest and least coherent tracing clock.
+ *
+ * Useful for tracing that does not cross to other CPUs nor
+ * does it go through idle events.
+ */
+u64 notrace trace_clock_local(void)
+{
+	u64 clock;
+
+	/*
+	 * sched_clock() is an architecture implemented, fast, scalable,
+	 * lockless clock. It is not guaranteed to be coherent across
+	 * CPUs, nor across CPU idle events.
+	 */
+	preempt_disable_notrace();
+	clock = sched_clock();
+	preempt_enable_notrace();
+
+	return clock;
+}
+EXPORT_SYMBOL_GPL(trace_clock_local);
+
+/*
+ * trace_clock(): 'between' trace clock. Not completely serialized,
+ * but not completely incorrect when crossing CPUs either.
+ *
+ * This is based on cpu_clock(), which will allow at most ~1 jiffy of
+ * jitter between CPUs. So it's a pretty scalable clock, but there
+ * can be offsets in the trace data.
+ */
+u64 notrace trace_clock(void)
+{
+	return local_clock();
+}
+EXPORT_SYMBOL_GPL(trace_clock);
+
+/*
+ * trace_jiffy_clock(): Simply use jiffies as a clock counter.
+ * Note that this use of jiffies_64 is not completely safe on
+ * 32-bit systems. But the window is tiny, and the effect if
+ * we are affected is that we will have an obviously bogus
+ * timestamp on a trace event - i.e. not life threatening.
+ */
+u64 notrace trace_clock_jiffies(void)
+{
+	return jiffies_64_to_clock_t(jiffies_64 - INITIAL_JIFFIES);
+}
+EXPORT_SYMBOL_GPL(trace_clock_jiffies);
+
+/*
+ * trace_clock_global(): special globally coherent trace clock
+ *
+ * It has higher overhead than the other trace clocks but is still
+ * an order of magnitude faster than GTOD derived hardware clocks.
+ *
+ * Used by plugins that need globally coherent timestamps.
+ */
+
+/* keep prev_time and lock in the same cacheline. */
+static struct {
+	u64 prev_time;
+	arch_spinlock_t lock;
+} trace_clock_struct ____cacheline_aligned_in_smp =
+	{
+		.lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED,
+	};
+
+u64 notrace trace_clock_global(void)
+{
+	unsigned long flags;
+	int this_cpu;
+	u64 now, prev_time;
+
+	raw_local_irq_save(flags);
+
+	this_cpu = raw_smp_processor_id();
+
+	/*
+	 * The global clock "guarantees" that the events are ordered
+	 * between CPUs. But if two events on two different CPUS call
+	 * trace_clock_global at roughly the same time, it really does
+	 * not matter which one gets the earlier time. Just make sure
+	 * that the same CPU will always show a monotonic clock.
+	 *
+	 * Use a read memory barrier to get the latest written
+	 * time that was recorded.
+	 */
+	smp_rmb();
+	prev_time = READ_ONCE(trace_clock_struct.prev_time);
+	now = sched_clock_cpu(this_cpu);
+
+	/* Make sure that now is always greater than or equal to prev_time */
+	if ((s64)(now - prev_time) < 0)
+		now = prev_time;
+
+	/*
+	 * If in an NMI context then dont risk lockups and simply return
+	 * the current time.
+	 */
+	if (unlikely(in_nmi()))
+		goto out;
+
+	/* Tracing can cause strange recursion, always use a try lock */
+	if (arch_spin_trylock(&trace_clock_struct.lock)) {
+		/* Reread prev_time in case it was already updated */
+		prev_time = READ_ONCE(trace_clock_struct.prev_time);
+		if ((s64)(now - prev_time) < 0)
+			now = prev_time;
+
+		trace_clock_struct.prev_time = now;
+
+		/* The unlock acts as the wmb for the above rmb */
+		arch_spin_unlock(&trace_clock_struct.lock);
+	}
+ out:
+	raw_local_irq_restore(flags);
+
+	return now;
+}
+EXPORT_SYMBOL_GPL(trace_clock_global);
+
+static atomic64_t trace_counter;
+
+/*
+ * trace_clock_counter(): simply an atomic counter.
+ * Use the trace_counter "counter" for cases where you do not care
+ * about timings, but are interested in strict ordering.
+ */
+u64 notrace trace_clock_counter(void)
+{
+	return atomic64_add_return(1, &trace_counter);
+}
diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c
new file mode 100644
index 000000000..4376887e0
--- /dev/null
+++ b/kernel/trace/trace_dynevent.c
@@ -0,0 +1,483 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic dynamic event control interface
+ *
+ * Copyright (C) 2018 Masami Hiramatsu <mhiramat@kernel.org>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/tracefs.h>
+
+#include "trace.h"
+#include "trace_output.h"	/* for trace_event_sem */
+#include "trace_dynevent.h"
+
+static DEFINE_MUTEX(dyn_event_ops_mutex);
+static LIST_HEAD(dyn_event_ops_list);
+
+bool trace_event_dyn_try_get_ref(struct trace_event_call *dyn_call)
+{
+	struct trace_event_call *call;
+	bool ret = false;
+
+	if (WARN_ON_ONCE(!(dyn_call->flags & TRACE_EVENT_FL_DYNAMIC)))
+		return false;
+
+	down_read(&trace_event_sem);
+	list_for_each_entry(call, &ftrace_events, list) {
+		if (call == dyn_call) {
+			atomic_inc(&dyn_call->refcnt);
+			ret = true;
+		}
+	}
+	up_read(&trace_event_sem);
+	return ret;
+}
+
+void trace_event_dyn_put_ref(struct trace_event_call *call)
+{
+	if (WARN_ON_ONCE(!(call->flags & TRACE_EVENT_FL_DYNAMIC)))
+		return;
+
+	if (WARN_ON_ONCE(atomic_read(&call->refcnt) <= 0)) {
+		atomic_set(&call->refcnt, 0);
+		return;
+	}
+
+	atomic_dec(&call->refcnt);
+}
+
+bool trace_event_dyn_busy(struct trace_event_call *call)
+{
+	return atomic_read(&call->refcnt) != 0;
+}
+
+int dyn_event_register(struct dyn_event_operations *ops)
+{
+	if (!ops || !ops->create || !ops->show || !ops->is_busy ||
+	    !ops->free || !ops->match)
+		return -EINVAL;
+
+	INIT_LIST_HEAD(&ops->list);
+	mutex_lock(&dyn_event_ops_mutex);
+	list_add_tail(&ops->list, &dyn_event_ops_list);
+	mutex_unlock(&dyn_event_ops_mutex);
+	return 0;
+}
+
+int dyn_event_release(const char *raw_command, struct dyn_event_operations *type)
+{
+	struct dyn_event *pos, *n;
+	char *system = NULL, *event, *p;
+	int argc, ret = -ENOENT;
+	char **argv;
+
+	argv = argv_split(GFP_KERNEL, raw_command, &argc);
+	if (!argv)
+		return -ENOMEM;
+
+	if (argv[0][0] == '-') {
+		if (argv[0][1] != ':') {
+			ret = -EINVAL;
+			goto out;
+		}
+		event = &argv[0][2];
+	} else {
+		event = strchr(argv[0], ':');
+		if (!event) {
+			ret = -EINVAL;
+			goto out;
+		}
+		event++;
+	}
+
+	p = strchr(event, '/');
+	if (p) {
+		system = event;
+		event = p + 1;
+		*p = '\0';
+	}
+	if (!system && event[0] == '\0') {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	mutex_lock(&event_mutex);
+	for_each_dyn_event_safe(pos, n) {
+		if (type && type != pos->ops)
+			continue;
+		if (!pos->ops->match(system, event,
+				argc - 1, (const char **)argv + 1, pos))
+			continue;
+
+		ret = pos->ops->free(pos);
+		if (ret)
+			break;
+	}
+	tracing_reset_all_online_cpus();
+	mutex_unlock(&event_mutex);
+out:
+	argv_free(argv);
+	return ret;
+}
+
+static int create_dyn_event(const char *raw_command)
+{
+	struct dyn_event_operations *ops;
+	int ret = -ENODEV;
+
+	if (raw_command[0] == '-' || raw_command[0] == '!')
+		return dyn_event_release(raw_command, NULL);
+
+	mutex_lock(&dyn_event_ops_mutex);
+	list_for_each_entry(ops, &dyn_event_ops_list, list) {
+		ret = ops->create(raw_command);
+		if (!ret || ret != -ECANCELED)
+			break;
+	}
+	mutex_unlock(&dyn_event_ops_mutex);
+	if (ret == -ECANCELED)
+		ret = -EINVAL;
+
+	return ret;
+}
+
+/* Protected by event_mutex */
+LIST_HEAD(dyn_event_list);
+
+void *dyn_event_seq_start(struct seq_file *m, loff_t *pos)
+{
+	mutex_lock(&event_mutex);
+	return seq_list_start(&dyn_event_list, *pos);
+}
+
+void *dyn_event_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return seq_list_next(v, &dyn_event_list, pos);
+}
+
+void dyn_event_seq_stop(struct seq_file *m, void *v)
+{
+	mutex_unlock(&event_mutex);
+}
+
+static int dyn_event_seq_show(struct seq_file *m, void *v)
+{
+	struct dyn_event *ev = v;
+
+	if (ev && ev->ops)
+		return ev->ops->show(m, ev);
+
+	return 0;
+}
+
+static const struct seq_operations dyn_event_seq_op = {
+	.start	= dyn_event_seq_start,
+	.next	= dyn_event_seq_next,
+	.stop	= dyn_event_seq_stop,
+	.show	= dyn_event_seq_show
+};
+
+/*
+ * dyn_events_release_all - Release all specific events
+ * @type:	the dyn_event_operations * which filters releasing events
+ *
+ * This releases all events which ->ops matches @type. If @type is NULL,
+ * all events are released.
+ * Return -EBUSY if any of them are in use, and return other errors when
+ * it failed to free the given event. Except for -EBUSY, event releasing
+ * process will be aborted at that point and there may be some other
+ * releasable events on the list.
+ */
+int dyn_events_release_all(struct dyn_event_operations *type)
+{
+	struct dyn_event *ev, *tmp;
+	int ret = 0;
+
+	mutex_lock(&event_mutex);
+	for_each_dyn_event(ev) {
+		if (type && ev->ops != type)
+			continue;
+		if (ev->ops->is_busy(ev)) {
+			ret = -EBUSY;
+			goto out;
+		}
+	}
+	for_each_dyn_event_safe(ev, tmp) {
+		if (type && ev->ops != type)
+			continue;
+		ret = ev->ops->free(ev);
+		if (ret)
+			break;
+	}
+out:
+	tracing_reset_all_online_cpus();
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+static int dyn_event_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = tracing_check_open_get_tr(NULL);
+	if (ret)
+		return ret;
+
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+		ret = dyn_events_release_all(NULL);
+		if (ret < 0)
+			return ret;
+	}
+
+	return seq_open(file, &dyn_event_seq_op);
+}
+
+static ssize_t dyn_event_write(struct file *file, const char __user *buffer,
+				size_t count, loff_t *ppos)
+{
+	return trace_parse_run_command(file, buffer, count, ppos,
+				       create_dyn_event);
+}
+
+static const struct file_operations dynamic_events_ops = {
+	.owner          = THIS_MODULE,
+	.open           = dyn_event_open,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release        = seq_release,
+	.write		= dyn_event_write,
+};
+
+/* Make a tracefs interface for controlling dynamic events */
+static __init int init_dynamic_event(void)
+{
+	int ret;
+
+	ret = tracing_init_dentry();
+	if (ret)
+		return 0;
+
+	trace_create_file("dynamic_events", TRACE_MODE_WRITE, NULL,
+			  NULL, &dynamic_events_ops);
+
+	return 0;
+}
+fs_initcall(init_dynamic_event);
+
+/**
+ * dynevent_arg_add - Add an arg to a dynevent_cmd
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event cmd
+ * @arg: The argument to append to the current cmd
+ * @check_arg: An (optional) pointer to a function checking arg sanity
+ *
+ * Append an argument to a dynevent_cmd.  The argument string will be
+ * appended to the current cmd string, followed by a separator, if
+ * applicable.  Before the argument is added, the @check_arg function,
+ * if present, will be used to check the sanity of the current arg
+ * string.
+ *
+ * The cmd string and separator should be set using the
+ * dynevent_arg_init() before any arguments are added using this
+ * function.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int dynevent_arg_add(struct dynevent_cmd *cmd,
+		     struct dynevent_arg *arg,
+		     dynevent_check_arg_fn_t check_arg)
+{
+	int ret = 0;
+
+	if (check_arg) {
+		ret = check_arg(arg);
+		if (ret)
+			return ret;
+	}
+
+	ret = seq_buf_printf(&cmd->seq, " %s%c", arg->str, arg->separator);
+	if (ret) {
+		pr_err("String is too long: %s%c\n", arg->str, arg->separator);
+		return -E2BIG;
+	}
+
+	return ret;
+}
+
+/**
+ * dynevent_arg_pair_add - Add an arg pair to a dynevent_cmd
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event cmd
+ * @arg_pair: The argument pair to append to the current cmd
+ * @check_arg: An (optional) pointer to a function checking arg sanity
+ *
+ * Append an argument pair to a dynevent_cmd.  An argument pair
+ * consists of a left-hand-side argument and a right-hand-side
+ * argument separated by an operator, which can be whitespace, all
+ * followed by a separator, if applicable.  This can be used to add
+ * arguments of the form 'type variable_name;' or 'x+y'.
+ *
+ * The lhs argument string will be appended to the current cmd string,
+ * followed by an operator, if applicable, followed by the rhs string,
+ * followed finally by a separator, if applicable.  Before the
+ * argument is added, the @check_arg function, if present, will be
+ * used to check the sanity of the current arg strings.
+ *
+ * The cmd strings, operator, and separator should be set using the
+ * dynevent_arg_pair_init() before any arguments are added using this
+ * function.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int dynevent_arg_pair_add(struct dynevent_cmd *cmd,
+			  struct dynevent_arg_pair *arg_pair,
+			  dynevent_check_arg_fn_t check_arg)
+{
+	int ret = 0;
+
+	if (check_arg) {
+		ret = check_arg(arg_pair);
+		if (ret)
+			return ret;
+	}
+
+	ret = seq_buf_printf(&cmd->seq, " %s%c%s%c", arg_pair->lhs,
+			     arg_pair->operator, arg_pair->rhs,
+			     arg_pair->separator);
+	if (ret) {
+		pr_err("field string is too long: %s%c%s%c\n", arg_pair->lhs,
+		       arg_pair->operator, arg_pair->rhs,
+		       arg_pair->separator);
+		return -E2BIG;
+	}
+
+	return ret;
+}
+
+/**
+ * dynevent_str_add - Add a string to a dynevent_cmd
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event cmd
+ * @str: The string to append to the current cmd
+ *
+ * Append a string to a dynevent_cmd.  The string will be appended to
+ * the current cmd string as-is, with nothing prepended or appended.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int dynevent_str_add(struct dynevent_cmd *cmd, const char *str)
+{
+	int ret = 0;
+
+	ret = seq_buf_puts(&cmd->seq, str);
+	if (ret) {
+		pr_err("String is too long: %s\n", str);
+		return -E2BIG;
+	}
+
+	return ret;
+}
+
+/**
+ * dynevent_cmd_init - Initialize a dynevent_cmd object
+ * @cmd: A pointer to the dynevent_cmd struct representing the cmd
+ * @buf: A pointer to the buffer to generate the command into
+ * @maxlen: The length of the buffer the command will be generated into
+ * @type: The type of the cmd, checked against further operations
+ * @run_command: The type-specific function that will actually run the command
+ *
+ * Initialize a dynevent_cmd.  A dynevent_cmd is used to build up and
+ * run dynamic event creation commands, such as commands for creating
+ * synthetic and kprobe events.  Before calling any of the functions
+ * used to build the command, a dynevent_cmd object should be
+ * instantiated and initialized using this function.
+ *
+ * The initialization sets things up by saving a pointer to the
+ * user-supplied buffer and its length via the @buf and @maxlen
+ * params, and by saving the cmd-specific @type and @run_command
+ * params which are used to check subsequent dynevent_cmd operations
+ * and actually run the command when complete.
+ */
+void dynevent_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen,
+		       enum dynevent_type type,
+		       dynevent_create_fn_t run_command)
+{
+	memset(cmd, '\0', sizeof(*cmd));
+
+	seq_buf_init(&cmd->seq, buf, maxlen);
+	cmd->type = type;
+	cmd->run_command = run_command;
+}
+
+/**
+ * dynevent_arg_init - Initialize a dynevent_arg object
+ * @arg: A pointer to the dynevent_arg struct representing the arg
+ * @separator: An (optional) separator, appended after adding the arg
+ *
+ * Initialize a dynevent_arg object.  A dynevent_arg represents an
+ * object used to append single arguments to the current command
+ * string.  After the arg string is successfully appended to the
+ * command string, the optional @separator is appended.  If no
+ * separator was specified when initializing the arg, a space will be
+ * appended.
+ */
+void dynevent_arg_init(struct dynevent_arg *arg,
+		       char separator)
+{
+	memset(arg, '\0', sizeof(*arg));
+
+	if (!separator)
+		separator = ' ';
+	arg->separator = separator;
+}
+
+/**
+ * dynevent_arg_pair_init - Initialize a dynevent_arg_pair object
+ * @arg_pair: A pointer to the dynevent_arg_pair struct representing the arg
+ * @operator: An (optional) operator, appended after adding the first arg
+ * @separator: An (optional) separator, appended after adding the second arg
+ *
+ * Initialize a dynevent_arg_pair object.  A dynevent_arg_pair
+ * represents an object used to append argument pairs such as 'type
+ * variable_name;' or 'x+y' to the current command string.  An
+ * argument pair consists of a left-hand-side argument and a
+ * right-hand-side argument separated by an operator, which can be
+ * whitespace, all followed by a separator, if applicable.  After the
+ * first arg string is successfully appended to the command string,
+ * the optional @operator is appended, followed by the second arg and
+ * optional @separator.  If no separator was specified when
+ * initializing the arg, a space will be appended.
+ */
+void dynevent_arg_pair_init(struct dynevent_arg_pair *arg_pair,
+			    char operator, char separator)
+{
+	memset(arg_pair, '\0', sizeof(*arg_pair));
+
+	if (!operator)
+		operator = ' ';
+	arg_pair->operator = operator;
+
+	if (!separator)
+		separator = ' ';
+	arg_pair->separator = separator;
+}
+
+/**
+ * dynevent_create - Create the dynamic event contained in dynevent_cmd
+ * @cmd: The dynevent_cmd object containing the dynamic event creation command
+ *
+ * Once a dynevent_cmd object has been successfully built up via the
+ * dynevent_cmd_init(), dynevent_arg_add() and dynevent_arg_pair_add()
+ * functions, this function runs the final command to actually create
+ * the event.
+ *
+ * Return: 0 if the event was successfully created, error otherwise.
+ */
+int dynevent_create(struct dynevent_cmd *cmd)
+{
+	return cmd->run_command(cmd);
+}
+EXPORT_SYMBOL_GPL(dynevent_create);
diff --git a/kernel/trace/trace_dynevent.h b/kernel/trace/trace_dynevent.h
new file mode 100644
index 000000000..936477a11
--- /dev/null
+++ b/kernel/trace/trace_dynevent.h
@@ -0,0 +1,154 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Common header file for generic dynamic events.
+ */
+
+#ifndef _TRACE_DYNEVENT_H
+#define _TRACE_DYNEVENT_H
+
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/seq_file.h>
+
+#include "trace.h"
+
+struct dyn_event;
+
+/**
+ * struct dyn_event_operations - Methods for each type of dynamic events
+ *
+ * These methods must be set for each type, since there is no default method.
+ * Before using this for dyn_event_init(), it must be registered by
+ * dyn_event_register().
+ *
+ * @create: Parse and create event method. This is invoked when user passes
+ *  a event definition to dynamic_events interface. This must not destruct
+ *  the arguments and return -ECANCELED if given arguments doesn't match its
+ *  command prefix.
+ * @show: Showing method. This is invoked when user reads the event definitions
+ *  via dynamic_events interface.
+ * @is_busy: Check whether given event is busy so that it can not be deleted.
+ *  Return true if it is busy, otherwise false.
+ * @free: Delete the given event. Return 0 if success, otherwise error.
+ * @match: Check whether given event and system name match this event. The argc
+ *  and argv is used for exact match. Return true if it matches, otherwise
+ *  false.
+ *
+ * Except for @create, these methods are called under holding event_mutex.
+ */
+struct dyn_event_operations {
+	struct list_head	list;
+	int (*create)(const char *raw_command);
+	int (*show)(struct seq_file *m, struct dyn_event *ev);
+	bool (*is_busy)(struct dyn_event *ev);
+	int (*free)(struct dyn_event *ev);
+	bool (*match)(const char *system, const char *event,
+		      int argc, const char **argv, struct dyn_event *ev);
+};
+
+/* Register new dyn_event type -- must be called at first */
+int dyn_event_register(struct dyn_event_operations *ops);
+
+/**
+ * struct dyn_event - Dynamic event list header
+ *
+ * The dyn_event structure encapsulates a list and a pointer to the operators
+ * for making a global list of dynamic events.
+ * User must includes this in each event structure, so that those events can
+ * be added/removed via dynamic_events interface.
+ */
+struct dyn_event {
+	struct list_head		list;
+	struct dyn_event_operations	*ops;
+};
+
+extern struct list_head dyn_event_list;
+
+static inline
+int dyn_event_init(struct dyn_event *ev, struct dyn_event_operations *ops)
+{
+	if (!ev || !ops)
+		return -EINVAL;
+
+	INIT_LIST_HEAD(&ev->list);
+	ev->ops = ops;
+	return 0;
+}
+
+static inline int dyn_event_add(struct dyn_event *ev,
+				struct trace_event_call *call)
+{
+	lockdep_assert_held(&event_mutex);
+
+	if (!ev || !ev->ops)
+		return -EINVAL;
+
+	call->flags |= TRACE_EVENT_FL_DYNAMIC;
+	list_add_tail(&ev->list, &dyn_event_list);
+	return 0;
+}
+
+static inline void dyn_event_remove(struct dyn_event *ev)
+{
+	lockdep_assert_held(&event_mutex);
+	list_del_init(&ev->list);
+}
+
+void *dyn_event_seq_start(struct seq_file *m, loff_t *pos);
+void *dyn_event_seq_next(struct seq_file *m, void *v, loff_t *pos);
+void dyn_event_seq_stop(struct seq_file *m, void *v);
+int dyn_events_release_all(struct dyn_event_operations *type);
+int dyn_event_release(const char *raw_command, struct dyn_event_operations *type);
+
+/*
+ * for_each_dyn_event	-	iterate over the dyn_event list
+ * @pos:	the struct dyn_event * to use as a loop cursor
+ *
+ * This is just a basement of for_each macro. Wrap this for
+ * each actual event structure with ops filtering.
+ */
+#define for_each_dyn_event(pos)	\
+	list_for_each_entry(pos, &dyn_event_list, list)
+
+/*
+ * for_each_dyn_event	-	iterate over the dyn_event list safely
+ * @pos:	the struct dyn_event * to use as a loop cursor
+ * @n:		the struct dyn_event * to use as temporary storage
+ */
+#define for_each_dyn_event_safe(pos, n)	\
+	list_for_each_entry_safe(pos, n, &dyn_event_list, list)
+
+extern void dynevent_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen,
+			      enum dynevent_type type,
+			      dynevent_create_fn_t run_command);
+
+typedef int (*dynevent_check_arg_fn_t)(void *data);
+
+struct dynevent_arg {
+	const char		*str;
+	char			separator; /* e.g. ';', ',', or nothing */
+};
+
+extern void dynevent_arg_init(struct dynevent_arg *arg,
+			      char separator);
+extern int dynevent_arg_add(struct dynevent_cmd *cmd,
+			    struct dynevent_arg *arg,
+			    dynevent_check_arg_fn_t check_arg);
+
+struct dynevent_arg_pair {
+	const char		*lhs;
+	const char		*rhs;
+	char			operator; /* e.g. '=' or nothing */
+	char			separator; /* e.g. ';', ',', or nothing */
+};
+
+extern void dynevent_arg_pair_init(struct dynevent_arg_pair *arg_pair,
+				   char operator, char separator);
+
+extern int dynevent_arg_pair_add(struct dynevent_cmd *cmd,
+				 struct dynevent_arg_pair *arg_pair,
+				 dynevent_check_arg_fn_t check_arg);
+extern int dynevent_str_add(struct dynevent_cmd *cmd, const char *str);
+
+#endif
diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
new file mode 100644
index 000000000..cd41e863b
--- /dev/null
+++ b/kernel/trace/trace_entries.h
@@ -0,0 +1,403 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file defines the trace event structures that go into the ring
+ * buffer directly. They are created via macros so that changes for them
+ * appear in the format file. Using macros will automate this process.
+ *
+ * The macro used to create a ftrace data structure is:
+ *
+ * FTRACE_ENTRY( name, struct_name, id, structure, print )
+ *
+ * @name: the name used the event name, as well as the name of
+ *   the directory that holds the format file.
+ *
+ * @struct_name: the name of the structure that is created.
+ *
+ * @id: The event identifier that is used to detect what event
+ *    this is from the ring buffer.
+ *
+ * @structure: the structure layout
+ *
+ *  - __field(	type,	item	)
+ *	  This is equivalent to declaring
+ *		type	item;
+ *	  in the structure.
+ *  - __array(	type,	item,	size	)
+ *	  This is equivalent to declaring
+ *		type	item[size];
+ *	  in the structure.
+ *
+ *   * for structures within structures, the format of the internal
+ *	structure is laid out. This allows the internal structure
+ *	to be deciphered for the format file. Although these macros
+ *	may become out of sync with the internal structure, they
+ *	will create a compile error if it happens. Since the
+ *	internal structures are just tracing helpers, this is not
+ *	an issue.
+ *
+ *	When an internal structure is used, it should use:
+ *
+ *	__field_struct(	type,	item	)
+ *
+ *	instead of __field. This will prevent it from being shown in
+ *	the output file. The fields in the structure should use.
+ *
+ *	__field_desc(	type,	container,	item		)
+ *	__array_desc(	type,	container,	item,	len	)
+ *
+ *	type, item and len are the same as __field and __array, but
+ *	container is added. This is the name of the item in
+ *	__field_struct that this is describing.
+ *
+ *
+ * @print: the print format shown to users in the format file.
+ */
+
+/*
+ * Function trace entry - function address and parent function address:
+ */
+FTRACE_ENTRY_REG(function, ftrace_entry,
+
+	TRACE_FN,
+
+	F_STRUCT(
+		__field_fn(	unsigned long,	ip		)
+		__field_fn(	unsigned long,	parent_ip	)
+	),
+
+	F_printk(" %ps <-- %ps",
+		 (void *)__entry->ip, (void *)__entry->parent_ip),
+
+	perf_ftrace_event_register
+);
+
+/* Function call entry */
+FTRACE_ENTRY_PACKED(funcgraph_entry, ftrace_graph_ent_entry,
+
+	TRACE_GRAPH_ENT,
+
+	F_STRUCT(
+		__field_struct(	struct ftrace_graph_ent,	graph_ent	)
+		__field_packed(	unsigned long,	graph_ent,	func		)
+		__field_packed(	int,		graph_ent,	depth		)
+	),
+
+	F_printk("--> %ps (%d)", (void *)__entry->func, __entry->depth)
+);
+
+/* Function return entry */
+FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry,
+
+	TRACE_GRAPH_RET,
+
+	F_STRUCT(
+		__field_struct(	struct ftrace_graph_ret,	ret	)
+		__field_packed(	unsigned long,	ret,		func	)
+		__field_packed(	int,		ret,		depth	)
+		__field_packed(	unsigned int,	ret,		overrun	)
+		__field_packed(	unsigned long long, ret,	calltime)
+		__field_packed(	unsigned long long, ret,	rettime	)
+	),
+
+	F_printk("<-- %ps (%d) (start: %llx  end: %llx) over: %d",
+		 (void *)__entry->func, __entry->depth,
+		 __entry->calltime, __entry->rettime,
+		 __entry->depth)
+);
+
+/*
+ * Context switch trace entry - which task (and prio) we switched from/to:
+ *
+ * This is used for both wakeup and context switches. We only want
+ * to create one structure, but we need two outputs for it.
+ */
+#define FTRACE_CTX_FIELDS					\
+	__field(	unsigned int,	prev_pid	)	\
+	__field(	unsigned int,	next_pid	)	\
+	__field(	unsigned int,	next_cpu	)       \
+	__field(	unsigned char,	prev_prio	)	\
+	__field(	unsigned char,	prev_state	)	\
+	__field(	unsigned char,	next_prio	)	\
+	__field(	unsigned char,	next_state	)
+
+FTRACE_ENTRY(context_switch, ctx_switch_entry,
+
+	TRACE_CTX,
+
+	F_STRUCT(
+		FTRACE_CTX_FIELDS
+	),
+
+	F_printk("%u:%u:%u  ==> %u:%u:%u [%03u]",
+		 __entry->prev_pid, __entry->prev_prio, __entry->prev_state,
+		 __entry->next_pid, __entry->next_prio, __entry->next_state,
+		 __entry->next_cpu)
+);
+
+/*
+ * FTRACE_ENTRY_DUP only creates the format file, it will not
+ *  create another structure.
+ */
+FTRACE_ENTRY_DUP(wakeup, ctx_switch_entry,
+
+	TRACE_WAKE,
+
+	F_STRUCT(
+		FTRACE_CTX_FIELDS
+	),
+
+	F_printk("%u:%u:%u  ==+ %u:%u:%u [%03u]",
+		 __entry->prev_pid, __entry->prev_prio, __entry->prev_state,
+		 __entry->next_pid, __entry->next_prio, __entry->next_state,
+		 __entry->next_cpu)
+);
+
+/*
+ * Stack-trace entry:
+ */
+
+#define FTRACE_STACK_ENTRIES	8
+
+FTRACE_ENTRY(kernel_stack, stack_entry,
+
+	TRACE_STACK,
+
+	F_STRUCT(
+		__field(	int,		size	)
+		__array(	unsigned long,	caller,	FTRACE_STACK_ENTRIES	)
+	),
+
+	F_printk("\t=> %ps\n\t=> %ps\n\t=> %ps\n"
+		 "\t=> %ps\n\t=> %ps\n\t=> %ps\n"
+		 "\t=> %ps\n\t=> %ps\n",
+		 (void *)__entry->caller[0], (void *)__entry->caller[1],
+		 (void *)__entry->caller[2], (void *)__entry->caller[3],
+		 (void *)__entry->caller[4], (void *)__entry->caller[5],
+		 (void *)__entry->caller[6], (void *)__entry->caller[7])
+);
+
+FTRACE_ENTRY(user_stack, userstack_entry,
+
+	TRACE_USER_STACK,
+
+	F_STRUCT(
+		__field(	unsigned int,	tgid	)
+		__array(	unsigned long,	caller, FTRACE_STACK_ENTRIES	)
+	),
+
+	F_printk("\t=> %ps\n\t=> %ps\n\t=> %ps\n"
+		 "\t=> %ps\n\t=> %ps\n\t=> %ps\n"
+		 "\t=> %ps\n\t=> %ps\n",
+		 (void *)__entry->caller[0], (void *)__entry->caller[1],
+		 (void *)__entry->caller[2], (void *)__entry->caller[3],
+		 (void *)__entry->caller[4], (void *)__entry->caller[5],
+		 (void *)__entry->caller[6], (void *)__entry->caller[7])
+);
+
+/*
+ * trace_printk entry:
+ */
+FTRACE_ENTRY(bprint, bprint_entry,
+
+	TRACE_BPRINT,
+
+	F_STRUCT(
+		__field(	unsigned long,	ip	)
+		__field(	const char *,	fmt	)
+		__dynamic_array(	u32,	buf	)
+	),
+
+	F_printk("%ps: %s",
+		 (void *)__entry->ip, __entry->fmt)
+);
+
+FTRACE_ENTRY_REG(print, print_entry,
+
+	TRACE_PRINT,
+
+	F_STRUCT(
+		__field(	unsigned long,	ip	)
+		__dynamic_array(	char,	buf	)
+	),
+
+	F_printk("%ps: %s",
+		 (void *)__entry->ip, __entry->buf),
+
+	ftrace_event_register
+);
+
+FTRACE_ENTRY(raw_data, raw_data_entry,
+
+	TRACE_RAW_DATA,
+
+	F_STRUCT(
+		__field(	unsigned int,	id	)
+		__dynamic_array(	char,	buf	)
+	),
+
+	F_printk("id:%04x %08x",
+		 __entry->id, (int)__entry->buf[0])
+);
+
+FTRACE_ENTRY(bputs, bputs_entry,
+
+	TRACE_BPUTS,
+
+	F_STRUCT(
+		__field(	unsigned long,	ip	)
+		__field(	const char *,	str	)
+	),
+
+	F_printk("%ps: %s",
+		 (void *)__entry->ip, __entry->str)
+);
+
+FTRACE_ENTRY(mmiotrace_rw, trace_mmiotrace_rw,
+
+	TRACE_MMIO_RW,
+
+	F_STRUCT(
+		__field_struct(	struct mmiotrace_rw,	rw	)
+		__field_desc(	resource_size_t, rw,	phys	)
+		__field_desc(	unsigned long,	rw,	value	)
+		__field_desc(	unsigned long,	rw,	pc	)
+		__field_desc(	int,		rw,	map_id	)
+		__field_desc(	unsigned char,	rw,	opcode	)
+		__field_desc(	unsigned char,	rw,	width	)
+	),
+
+	F_printk("%lx %lx %lx %d %x %x",
+		 (unsigned long)__entry->phys, __entry->value, __entry->pc,
+		 __entry->map_id, __entry->opcode, __entry->width)
+);
+
+FTRACE_ENTRY(mmiotrace_map, trace_mmiotrace_map,
+
+	TRACE_MMIO_MAP,
+
+	F_STRUCT(
+		__field_struct(	struct mmiotrace_map,	map	)
+		__field_desc(	resource_size_t, map,	phys	)
+		__field_desc(	unsigned long,	map,	virt	)
+		__field_desc(	unsigned long,	map,	len	)
+		__field_desc(	int,		map,	map_id	)
+		__field_desc(	unsigned char,	map,	opcode	)
+	),
+
+	F_printk("%lx %lx %lx %d %x",
+		 (unsigned long)__entry->phys, __entry->virt, __entry->len,
+		 __entry->map_id, __entry->opcode)
+);
+
+
+#define TRACE_FUNC_SIZE 30
+#define TRACE_FILE_SIZE 20
+
+FTRACE_ENTRY(branch, trace_branch,
+
+	TRACE_BRANCH,
+
+	F_STRUCT(
+		__field(	unsigned int,	line				)
+		__array(	char,		func,	TRACE_FUNC_SIZE+1	)
+		__array(	char,		file,	TRACE_FILE_SIZE+1	)
+		__field(	char,		correct				)
+		__field(	char,		constant			)
+	),
+
+	F_printk("%u:%s:%s (%u)%s",
+		 __entry->line,
+		 __entry->func, __entry->file, __entry->correct,
+		 __entry->constant ? " CONSTANT" : "")
+);
+
+
+FTRACE_ENTRY(hwlat, hwlat_entry,
+
+	TRACE_HWLAT,
+
+	F_STRUCT(
+		__field(	u64,			duration	)
+		__field(	u64,			outer_duration	)
+		__field(	u64,			nmi_total_ts	)
+		__field_struct( struct timespec64,	timestamp	)
+		__field_desc(	s64,	timestamp,	tv_sec		)
+		__field_desc(	long,	timestamp,	tv_nsec		)
+		__field(	unsigned int,		nmi_count	)
+		__field(	unsigned int,		seqnum		)
+		__field(	unsigned int,		count		)
+	),
+
+	F_printk("cnt:%u\tts:%010llu.%010lu\tinner:%llu\touter:%llu\tcount:%d\tnmi-ts:%llu\tnmi-count:%u\n",
+		 __entry->seqnum,
+		 __entry->tv_sec,
+		 __entry->tv_nsec,
+		 __entry->duration,
+		 __entry->outer_duration,
+		 __entry->count,
+		 __entry->nmi_total_ts,
+		 __entry->nmi_count)
+);
+
+#define FUNC_REPEATS_GET_DELTA_TS(entry)				\
+	(((u64)(entry)->top_delta_ts << 32) | (entry)->bottom_delta_ts)	\
+
+FTRACE_ENTRY(func_repeats, func_repeats_entry,
+
+	TRACE_FUNC_REPEATS,
+
+	F_STRUCT(
+		__field(	unsigned long,	ip		)
+		__field(	unsigned long,	parent_ip	)
+		__field(	u16	,	count		)
+		__field(	u16	,	top_delta_ts	)
+		__field(	u32	,	bottom_delta_ts	)
+	),
+
+	F_printk(" %ps <-%ps\t(repeats:%u  delta: -%llu)",
+		 (void *)__entry->ip,
+		 (void *)__entry->parent_ip,
+		 __entry->count,
+		 FUNC_REPEATS_GET_DELTA_TS(__entry))
+);
+
+FTRACE_ENTRY(osnoise, osnoise_entry,
+
+	TRACE_OSNOISE,
+
+	F_STRUCT(
+		__field(	u64,			noise		)
+		__field(	u64,			runtime		)
+		__field(	u64,			max_sample	)
+		__field(	unsigned int,		hw_count	)
+		__field(	unsigned int,		nmi_count	)
+		__field(	unsigned int,		irq_count	)
+		__field(	unsigned int,		softirq_count	)
+		__field(	unsigned int,		thread_count	)
+	),
+
+	F_printk("noise:%llu\tmax_sample:%llu\thw:%u\tnmi:%u\tirq:%u\tsoftirq:%u\tthread:%u\n",
+		 __entry->noise,
+		 __entry->max_sample,
+		 __entry->hw_count,
+		 __entry->nmi_count,
+		 __entry->irq_count,
+		 __entry->softirq_count,
+		 __entry->thread_count)
+);
+
+FTRACE_ENTRY(timerlat, timerlat_entry,
+
+	TRACE_TIMERLAT,
+
+	F_STRUCT(
+		__field(	unsigned int,		seqnum		)
+		__field(	int,			context		)
+		__field(	u64,			timer_latency	)
+	),
+
+	F_printk("seq:%u\tcontext:%d\ttimer_latency:%llu\n",
+		 __entry->seqnum,
+		 __entry->context,
+		 __entry->timer_latency)
+);
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
new file mode 100644
index 000000000..d2370cdb4
--- /dev/null
+++ b/kernel/trace/trace_eprobe.c
@@ -0,0 +1,1095 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * event probes
+ *
+ * Part of this code was copied from kernel/trace/trace_kprobe.c written by
+ * Masami Hiramatsu <mhiramat@kernel.org>
+ *
+ * Copyright (C) 2021, VMware Inc, Steven Rostedt <rostedt@goodmis.org>
+ * Copyright (C) 2021, VMware Inc, Tzvetomir Stoyanov tz.stoyanov@gmail.com>
+ *
+ */
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/ftrace.h>
+
+#include "trace_dynevent.h"
+#include "trace_probe.h"
+#include "trace_probe_tmpl.h"
+#include "trace_probe_kernel.h"
+
+#define EPROBE_EVENT_SYSTEM "eprobes"
+
+struct trace_eprobe {
+	/* tracepoint system */
+	const char *event_system;
+
+	/* tracepoint event */
+	const char *event_name;
+
+	/* filter string for the tracepoint */
+	char *filter_str;
+
+	struct trace_event_call *event;
+
+	struct dyn_event	devent;
+	struct trace_probe	tp;
+};
+
+struct eprobe_data {
+	struct trace_event_file	*file;
+	struct trace_eprobe	*ep;
+};
+
+static int __trace_eprobe_create(int argc, const char *argv[]);
+
+static void trace_event_probe_cleanup(struct trace_eprobe *ep)
+{
+	if (!ep)
+		return;
+	trace_probe_cleanup(&ep->tp);
+	kfree(ep->event_name);
+	kfree(ep->event_system);
+	if (ep->event)
+		trace_event_put_ref(ep->event);
+	kfree(ep->filter_str);
+	kfree(ep);
+}
+
+static struct trace_eprobe *to_trace_eprobe(struct dyn_event *ev)
+{
+	return container_of(ev, struct trace_eprobe, devent);
+}
+
+static int eprobe_dyn_event_create(const char *raw_command)
+{
+	return trace_probe_create(raw_command, __trace_eprobe_create);
+}
+
+static int eprobe_dyn_event_show(struct seq_file *m, struct dyn_event *ev)
+{
+	struct trace_eprobe *ep = to_trace_eprobe(ev);
+	int i;
+
+	seq_printf(m, "e:%s/%s", trace_probe_group_name(&ep->tp),
+				trace_probe_name(&ep->tp));
+	seq_printf(m, " %s.%s", ep->event_system, ep->event_name);
+
+	for (i = 0; i < ep->tp.nr_args; i++)
+		seq_printf(m, " %s=%s", ep->tp.args[i].name, ep->tp.args[i].comm);
+	seq_putc(m, '\n');
+
+	return 0;
+}
+
+static int unregister_trace_eprobe(struct trace_eprobe *ep)
+{
+	/* If other probes are on the event, just unregister eprobe */
+	if (trace_probe_has_sibling(&ep->tp))
+		goto unreg;
+
+	/* Enabled event can not be unregistered */
+	if (trace_probe_is_enabled(&ep->tp))
+		return -EBUSY;
+
+	/* Will fail if probe is being used by ftrace or perf */
+	if (trace_probe_unregister_event_call(&ep->tp))
+		return -EBUSY;
+
+unreg:
+	dyn_event_remove(&ep->devent);
+	trace_probe_unlink(&ep->tp);
+
+	return 0;
+}
+
+static int eprobe_dyn_event_release(struct dyn_event *ev)
+{
+	struct trace_eprobe *ep = to_trace_eprobe(ev);
+	int ret = unregister_trace_eprobe(ep);
+
+	if (!ret)
+		trace_event_probe_cleanup(ep);
+	return ret;
+}
+
+static bool eprobe_dyn_event_is_busy(struct dyn_event *ev)
+{
+	struct trace_eprobe *ep = to_trace_eprobe(ev);
+
+	return trace_probe_is_enabled(&ep->tp);
+}
+
+static bool eprobe_dyn_event_match(const char *system, const char *event,
+			int argc, const char **argv, struct dyn_event *ev)
+{
+	struct trace_eprobe *ep = to_trace_eprobe(ev);
+	const char *slash;
+
+	/*
+	 * We match the following:
+	 *  event only			- match all eprobes with event name
+	 *  system and event only	- match all system/event probes
+	 *  system only			- match all system probes
+	 *
+	 * The below has the above satisfied with more arguments:
+	 *
+	 *  attached system/event	- If the arg has the system and event
+	 *				  the probe is attached to, match
+	 *				  probes with the attachment.
+	 *
+	 *  If any more args are given, then it requires a full match.
+	 */
+
+	/*
+	 * If system exists, but this probe is not part of that system
+	 * do not match.
+	 */
+	if (system && strcmp(trace_probe_group_name(&ep->tp), system) != 0)
+		return false;
+
+	/* Must match the event name */
+	if (event[0] != '\0' && strcmp(trace_probe_name(&ep->tp), event) != 0)
+		return false;
+
+	/* No arguments match all */
+	if (argc < 1)
+		return true;
+
+	/* First argument is the system/event the probe is attached to */
+
+	slash = strchr(argv[0], '/');
+	if (!slash)
+		slash = strchr(argv[0], '.');
+	if (!slash)
+		return false;
+
+	if (strncmp(ep->event_system, argv[0], slash - argv[0]))
+		return false;
+	if (strcmp(ep->event_name, slash + 1))
+		return false;
+
+	argc--;
+	argv++;
+
+	/* If there are no other args, then match */
+	if (argc < 1)
+		return true;
+
+	return trace_probe_match_command_args(&ep->tp, argc, argv);
+}
+
+static struct dyn_event_operations eprobe_dyn_event_ops = {
+	.create = eprobe_dyn_event_create,
+	.show = eprobe_dyn_event_show,
+	.is_busy = eprobe_dyn_event_is_busy,
+	.free = eprobe_dyn_event_release,
+	.match = eprobe_dyn_event_match,
+};
+
+static struct trace_eprobe *alloc_event_probe(const char *group,
+					      const char *this_event,
+					      struct trace_event_call *event,
+					      int nargs)
+{
+	struct trace_eprobe *ep;
+	const char *event_name;
+	const char *sys_name;
+	int ret = -ENOMEM;
+
+	if (!event)
+		return ERR_PTR(-ENODEV);
+
+	sys_name = event->class->system;
+	event_name = trace_event_name(event);
+
+	ep = kzalloc(struct_size(ep, tp.args, nargs), GFP_KERNEL);
+	if (!ep) {
+		trace_event_put_ref(event);
+		goto error;
+	}
+	ep->event = event;
+	ep->event_name = kstrdup(event_name, GFP_KERNEL);
+	if (!ep->event_name)
+		goto error;
+	ep->event_system = kstrdup(sys_name, GFP_KERNEL);
+	if (!ep->event_system)
+		goto error;
+
+	ret = trace_probe_init(&ep->tp, this_event, group, false);
+	if (ret < 0)
+		goto error;
+
+	dyn_event_init(&ep->devent, &eprobe_dyn_event_ops);
+	return ep;
+error:
+	trace_event_probe_cleanup(ep);
+	return ERR_PTR(ret);
+}
+
+static int trace_eprobe_tp_arg_update(struct trace_eprobe *ep, int i)
+{
+	struct probe_arg *parg = &ep->tp.args[i];
+	struct ftrace_event_field *field;
+	struct list_head *head;
+	int ret = -ENOENT;
+
+	head = trace_get_fields(ep->event);
+	list_for_each_entry(field, head, link) {
+		if (!strcmp(parg->code->data, field->name)) {
+			kfree(parg->code->data);
+			parg->code->data = field;
+			return 0;
+		}
+	}
+
+	/*
+	 * Argument not found on event. But allow for comm and COMM
+	 * to be used to get the current->comm.
+	 */
+	if (strcmp(parg->code->data, "COMM") == 0 ||
+	    strcmp(parg->code->data, "comm") == 0) {
+		parg->code->op = FETCH_OP_COMM;
+		ret = 0;
+	}
+
+	kfree(parg->code->data);
+	parg->code->data = NULL;
+	return ret;
+}
+
+static int eprobe_event_define_fields(struct trace_event_call *event_call)
+{
+	struct eprobe_trace_entry_head field;
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(event_call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENOENT;
+
+	return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
+}
+
+static struct trace_event_fields eprobe_fields_array[] = {
+	{ .type = TRACE_FUNCTION_TYPE,
+	  .define_fields = eprobe_event_define_fields },
+	{}
+};
+
+/* Event entry printers */
+static enum print_line_t
+print_eprobe_event(struct trace_iterator *iter, int flags,
+		   struct trace_event *event)
+{
+	struct eprobe_trace_entry_head *field;
+	struct trace_event_call *pevent;
+	struct trace_event *probed_event;
+	struct trace_seq *s = &iter->seq;
+	struct trace_eprobe *ep;
+	struct trace_probe *tp;
+	unsigned int type;
+
+	field = (struct eprobe_trace_entry_head *)iter->ent;
+	tp = trace_probe_primary_from_call(
+		container_of(event, struct trace_event_call, event));
+	if (WARN_ON_ONCE(!tp))
+		goto out;
+
+	ep = container_of(tp, struct trace_eprobe, tp);
+	type = ep->event->event.type;
+
+	trace_seq_printf(s, "%s: (", trace_probe_name(tp));
+
+	probed_event = ftrace_find_event(type);
+	if (probed_event) {
+		pevent = container_of(probed_event, struct trace_event_call, event);
+		trace_seq_printf(s, "%s.%s", pevent->class->system,
+				 trace_event_name(pevent));
+	} else {
+		trace_seq_printf(s, "%u", type);
+	}
+
+	trace_seq_putc(s, ')');
+
+	if (print_probe_args(s, tp->args, tp->nr_args,
+			     (u8 *)&field[1], field) < 0)
+		goto out;
+
+	trace_seq_putc(s, '\n');
+ out:
+	return trace_handle_return(s);
+}
+
+static unsigned long get_event_field(struct fetch_insn *code, void *rec)
+{
+	struct ftrace_event_field *field = code->data;
+	unsigned long val;
+	void *addr;
+
+	addr = rec + field->offset;
+
+	if (is_string_field(field)) {
+		switch (field->filter_type) {
+		case FILTER_DYN_STRING:
+			val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff));
+			break;
+		case FILTER_RDYN_STRING:
+			val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff));
+			break;
+		case FILTER_STATIC_STRING:
+			val = (unsigned long)addr;
+			break;
+		case FILTER_PTR_STRING:
+			val = (unsigned long)(*(char *)addr);
+			break;
+		default:
+			WARN_ON_ONCE(1);
+			return 0;
+		}
+		return val;
+	}
+
+	switch (field->size) {
+	case 1:
+		if (field->is_signed)
+			val = *(char *)addr;
+		else
+			val = *(unsigned char *)addr;
+		break;
+	case 2:
+		if (field->is_signed)
+			val = *(short *)addr;
+		else
+			val = *(unsigned short *)addr;
+		break;
+	case 4:
+		if (field->is_signed)
+			val = *(int *)addr;
+		else
+			val = *(unsigned int *)addr;
+		break;
+	default:
+		if (field->is_signed)
+			val = *(long *)addr;
+		else
+			val = *(unsigned long *)addr;
+		break;
+	}
+	return val;
+}
+
+static int get_eprobe_size(struct trace_probe *tp, void *rec)
+{
+	struct fetch_insn *code;
+	struct probe_arg *arg;
+	int i, len, ret = 0;
+
+	for (i = 0; i < tp->nr_args; i++) {
+		arg = tp->args + i;
+		if (arg->dynamic) {
+			unsigned long val;
+
+			code = arg->code;
+ retry:
+			switch (code->op) {
+			case FETCH_OP_TP_ARG:
+				val = get_event_field(code, rec);
+				break;
+			case FETCH_OP_IMM:
+				val = code->immediate;
+				break;
+			case FETCH_OP_COMM:
+				val = (unsigned long)current->comm;
+				break;
+			case FETCH_OP_DATA:
+				val = (unsigned long)code->data;
+				break;
+			case FETCH_NOP_SYMBOL:	/* Ignore a place holder */
+				code++;
+				goto retry;
+			default:
+				continue;
+			}
+			code++;
+			len = process_fetch_insn_bottom(code, val, NULL, NULL);
+			if (len > 0)
+				ret += len;
+		}
+	}
+
+	return ret;
+}
+
+/* Kprobe specific fetch functions */
+
+/* Note that we don't verify it, since the code does not come from user space */
+static int
+process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
+		   void *base)
+{
+	unsigned long val;
+
+ retry:
+	switch (code->op) {
+	case FETCH_OP_TP_ARG:
+		val = get_event_field(code, rec);
+		break;
+	case FETCH_OP_IMM:
+		val = code->immediate;
+		break;
+	case FETCH_OP_COMM:
+		val = (unsigned long)current->comm;
+		break;
+	case FETCH_OP_DATA:
+		val = (unsigned long)code->data;
+		break;
+	case FETCH_NOP_SYMBOL:	/* Ignore a place holder */
+		code++;
+		goto retry;
+	default:
+		return -EILSEQ;
+	}
+	code++;
+	return process_fetch_insn_bottom(code, val, dest, base);
+}
+NOKPROBE_SYMBOL(process_fetch_insn)
+
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline int
+fetch_store_strlen_user(unsigned long addr)
+{
+	return kern_fetch_store_strlen_user(addr);
+}
+
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline int
+fetch_store_strlen(unsigned long addr)
+{
+	return kern_fetch_store_strlen(addr);
+}
+
+/*
+ * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
+ * with max length and relative data location.
+ */
+static nokprobe_inline int
+fetch_store_string_user(unsigned long addr, void *dest, void *base)
+{
+	return kern_fetch_store_string_user(addr, dest, base);
+}
+
+/*
+ * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
+ * length and relative data location.
+ */
+static nokprobe_inline int
+fetch_store_string(unsigned long addr, void *dest, void *base)
+{
+	return kern_fetch_store_string(addr, dest, base);
+}
+
+static nokprobe_inline int
+probe_mem_read_user(void *dest, void *src, size_t size)
+{
+	const void __user *uaddr =  (__force const void __user *)src;
+
+	return copy_from_user_nofault(dest, uaddr, size);
+}
+
+static nokprobe_inline int
+probe_mem_read(void *dest, void *src, size_t size)
+{
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+	if ((unsigned long)src < TASK_SIZE)
+		return probe_mem_read_user(dest, src, size);
+#endif
+	return copy_from_kernel_nofault(dest, src, size);
+}
+
+/* eprobe handler */
+static inline void
+__eprobe_trace_func(struct eprobe_data *edata, void *rec)
+{
+	struct eprobe_trace_entry_head *entry;
+	struct trace_event_call *call = trace_probe_event_call(&edata->ep->tp);
+	struct trace_event_buffer fbuffer;
+	int dsize;
+
+	if (WARN_ON_ONCE(call != edata->file->event_call))
+		return;
+
+	if (trace_trigger_soft_disabled(edata->file))
+		return;
+
+	dsize = get_eprobe_size(&edata->ep->tp, rec);
+
+	entry = trace_event_buffer_reserve(&fbuffer, edata->file,
+					   sizeof(*entry) + edata->ep->tp.size + dsize);
+
+	if (!entry)
+		return;
+
+	entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
+	store_trace_args(&entry[1], &edata->ep->tp, rec, sizeof(*entry), dsize);
+
+	trace_event_buffer_commit(&fbuffer);
+}
+
+/*
+ * The event probe implementation uses event triggers to get access to
+ * the event it is attached to, but is not an actual trigger. The below
+ * functions are just stubs to fulfill what is needed to use the trigger
+ * infrastructure.
+ */
+static int eprobe_trigger_init(struct event_trigger_data *data)
+{
+	return 0;
+}
+
+static void eprobe_trigger_free(struct event_trigger_data *data)
+{
+
+}
+
+static int eprobe_trigger_print(struct seq_file *m,
+				struct event_trigger_data *data)
+{
+	/* Do not print eprobe event triggers */
+	return 0;
+}
+
+static void eprobe_trigger_func(struct event_trigger_data *data,
+				struct trace_buffer *buffer, void *rec,
+				struct ring_buffer_event *rbe)
+{
+	struct eprobe_data *edata = data->private_data;
+
+	if (unlikely(!rec))
+		return;
+
+	if (unlikely(!rec))
+		return;
+
+	__eprobe_trace_func(edata, rec);
+}
+
+static struct event_trigger_ops eprobe_trigger_ops = {
+	.trigger		= eprobe_trigger_func,
+	.print			= eprobe_trigger_print,
+	.init			= eprobe_trigger_init,
+	.free			= eprobe_trigger_free,
+};
+
+static int eprobe_trigger_cmd_parse(struct event_command *cmd_ops,
+				    struct trace_event_file *file,
+				    char *glob, char *cmd,
+				    char *param_and_filter)
+{
+	return -1;
+}
+
+static int eprobe_trigger_reg_func(char *glob,
+				   struct event_trigger_data *data,
+				   struct trace_event_file *file)
+{
+	return -1;
+}
+
+static void eprobe_trigger_unreg_func(char *glob,
+				      struct event_trigger_data *data,
+				      struct trace_event_file *file)
+{
+
+}
+
+static struct event_trigger_ops *eprobe_trigger_get_ops(char *cmd,
+							char *param)
+{
+	return &eprobe_trigger_ops;
+}
+
+static struct event_command event_trigger_cmd = {
+	.name			= "eprobe",
+	.trigger_type		= ETT_EVENT_EPROBE,
+	.flags			= EVENT_CMD_FL_NEEDS_REC,
+	.parse			= eprobe_trigger_cmd_parse,
+	.reg			= eprobe_trigger_reg_func,
+	.unreg			= eprobe_trigger_unreg_func,
+	.unreg_all		= NULL,
+	.get_trigger_ops	= eprobe_trigger_get_ops,
+	.set_filter		= NULL,
+};
+
+static struct event_trigger_data *
+new_eprobe_trigger(struct trace_eprobe *ep, struct trace_event_file *file)
+{
+	struct event_trigger_data *trigger;
+	struct event_filter *filter = NULL;
+	struct eprobe_data *edata;
+	int ret;
+
+	edata = kzalloc(sizeof(*edata), GFP_KERNEL);
+	trigger = kzalloc(sizeof(*trigger), GFP_KERNEL);
+	if (!trigger || !edata) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	trigger->flags = EVENT_TRIGGER_FL_PROBE;
+	trigger->count = -1;
+	trigger->ops = &eprobe_trigger_ops;
+
+	/*
+	 * EVENT PROBE triggers are not registered as commands with
+	 * register_event_command(), as they are not controlled by the user
+	 * from the trigger file
+	 */
+	trigger->cmd_ops = &event_trigger_cmd;
+
+	INIT_LIST_HEAD(&trigger->list);
+
+	if (ep->filter_str) {
+		ret = create_event_filter(file->tr, ep->event,
+					ep->filter_str, false, &filter);
+		if (ret)
+			goto error;
+	}
+	RCU_INIT_POINTER(trigger->filter, filter);
+
+	edata->file = file;
+	edata->ep = ep;
+	trigger->private_data = edata;
+
+	return trigger;
+error:
+	free_event_filter(filter);
+	kfree(edata);
+	kfree(trigger);
+	return ERR_PTR(ret);
+}
+
+static int enable_eprobe(struct trace_eprobe *ep,
+			 struct trace_event_file *eprobe_file)
+{
+	struct event_trigger_data *trigger;
+	struct trace_event_file *file;
+	struct trace_array *tr = eprobe_file->tr;
+
+	file = find_event_file(tr, ep->event_system, ep->event_name);
+	if (!file)
+		return -ENOENT;
+	trigger = new_eprobe_trigger(ep, eprobe_file);
+	if (IS_ERR(trigger))
+		return PTR_ERR(trigger);
+
+	list_add_tail_rcu(&trigger->list, &file->triggers);
+
+	trace_event_trigger_enable_disable(file, 1);
+	update_cond_flag(file);
+
+	return 0;
+}
+
+static struct trace_event_functions eprobe_funcs = {
+	.trace		= print_eprobe_event
+};
+
+static int disable_eprobe(struct trace_eprobe *ep,
+			  struct trace_array *tr)
+{
+	struct event_trigger_data *trigger = NULL, *iter;
+	struct trace_event_file *file;
+	struct event_filter *filter;
+	struct eprobe_data *edata;
+
+	file = find_event_file(tr, ep->event_system, ep->event_name);
+	if (!file)
+		return -ENOENT;
+
+	list_for_each_entry(iter, &file->triggers, list) {
+		if (!(iter->flags & EVENT_TRIGGER_FL_PROBE))
+			continue;
+		edata = iter->private_data;
+		if (edata->ep == ep) {
+			trigger = iter;
+			break;
+		}
+	}
+	if (!trigger)
+		return -ENODEV;
+
+	list_del_rcu(&trigger->list);
+
+	trace_event_trigger_enable_disable(file, 0);
+	update_cond_flag(file);
+
+	/* Make sure nothing is using the edata or trigger */
+	tracepoint_synchronize_unregister();
+
+	filter = rcu_access_pointer(trigger->filter);
+
+	if (filter)
+		free_event_filter(filter);
+	kfree(edata);
+	kfree(trigger);
+
+	return 0;
+}
+
+static int enable_trace_eprobe(struct trace_event_call *call,
+			       struct trace_event_file *file)
+{
+	struct trace_probe *pos, *tp;
+	struct trace_eprobe *ep;
+	bool enabled;
+	int ret = 0;
+	int cnt = 0;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENODEV;
+	enabled = trace_probe_is_enabled(tp);
+
+	/* This also changes "enabled" state */
+	if (file) {
+		ret = trace_probe_add_file(tp, file);
+		if (ret)
+			return ret;
+	} else
+		trace_probe_set_flag(tp, TP_FLAG_PROFILE);
+
+	if (enabled)
+		return 0;
+
+	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
+		ep = container_of(pos, struct trace_eprobe, tp);
+		ret = enable_eprobe(ep, file);
+		if (ret)
+			break;
+		enabled = true;
+		cnt++;
+	}
+
+	if (ret) {
+		/* Failed to enable one of them. Roll back all */
+		if (enabled) {
+			/*
+			 * It's a bug if one failed for something other than memory
+			 * not being available but another eprobe succeeded.
+			 */
+			WARN_ON_ONCE(ret != -ENOMEM);
+
+			list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
+				ep = container_of(pos, struct trace_eprobe, tp);
+				disable_eprobe(ep, file->tr);
+				if (!--cnt)
+					break;
+			}
+		}
+		if (file)
+			trace_probe_remove_file(tp, file);
+		else
+			trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
+	}
+
+	return ret;
+}
+
+static int disable_trace_eprobe(struct trace_event_call *call,
+				struct trace_event_file *file)
+{
+	struct trace_probe *pos, *tp;
+	struct trace_eprobe *ep;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENODEV;
+
+	if (file) {
+		if (!trace_probe_get_file_link(tp, file))
+			return -ENOENT;
+		if (!trace_probe_has_single_file(tp))
+			goto out;
+		trace_probe_clear_flag(tp, TP_FLAG_TRACE);
+	} else
+		trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
+
+	if (!trace_probe_is_enabled(tp)) {
+		list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
+			ep = container_of(pos, struct trace_eprobe, tp);
+			disable_eprobe(ep, file->tr);
+		}
+	}
+
+ out:
+	if (file)
+		/*
+		 * Synchronization is done in below function. For perf event,
+		 * file == NULL and perf_trace_event_unreg() calls
+		 * tracepoint_synchronize_unregister() to ensure synchronize
+		 * event. We don't need to care about it.
+		 */
+		trace_probe_remove_file(tp, file);
+
+	return 0;
+}
+
+static int eprobe_register(struct trace_event_call *event,
+			   enum trace_reg type, void *data)
+{
+	struct trace_event_file *file = data;
+
+	switch (type) {
+	case TRACE_REG_REGISTER:
+		return enable_trace_eprobe(event, file);
+	case TRACE_REG_UNREGISTER:
+		return disable_trace_eprobe(event, file);
+#ifdef CONFIG_PERF_EVENTS
+	case TRACE_REG_PERF_REGISTER:
+	case TRACE_REG_PERF_UNREGISTER:
+	case TRACE_REG_PERF_OPEN:
+	case TRACE_REG_PERF_CLOSE:
+	case TRACE_REG_PERF_ADD:
+	case TRACE_REG_PERF_DEL:
+		return 0;
+#endif
+	}
+	return 0;
+}
+
+static inline void init_trace_eprobe_call(struct trace_eprobe *ep)
+{
+	struct trace_event_call *call = trace_probe_event_call(&ep->tp);
+
+	call->flags = TRACE_EVENT_FL_EPROBE;
+	call->event.funcs = &eprobe_funcs;
+	call->class->fields_array = eprobe_fields_array;
+	call->class->reg = eprobe_register;
+}
+
+static struct trace_event_call *
+find_and_get_event(const char *system, const char *event_name)
+{
+	struct trace_event_call *tp_event;
+	const char *name;
+
+	list_for_each_entry(tp_event, &ftrace_events, list) {
+		/* Skip other probes and ftrace events */
+		if (tp_event->flags &
+		    (TRACE_EVENT_FL_IGNORE_ENABLE |
+		     TRACE_EVENT_FL_KPROBE |
+		     TRACE_EVENT_FL_UPROBE |
+		     TRACE_EVENT_FL_EPROBE))
+			continue;
+		if (!tp_event->class->system ||
+		    strcmp(system, tp_event->class->system))
+			continue;
+		name = trace_event_name(tp_event);
+		if (!name || strcmp(event_name, name))
+			continue;
+		if (!trace_event_try_get_ref(tp_event)) {
+			return NULL;
+			break;
+		}
+		return tp_event;
+		break;
+	}
+	return NULL;
+}
+
+static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[], int i)
+{
+	unsigned int flags = TPARG_FL_KERNEL | TPARG_FL_TPOINT;
+	int ret;
+
+	ret = traceprobe_parse_probe_arg(&ep->tp, i, argv[i], flags);
+	if (ret)
+		return ret;
+
+	if (ep->tp.args[i].code->op == FETCH_OP_TP_ARG) {
+		ret = trace_eprobe_tp_arg_update(ep, i);
+		if (ret)
+			trace_probe_log_err(0, BAD_ATTACH_ARG);
+	}
+
+	/* Handle symbols "@" */
+	if (!ret)
+		ret = traceprobe_update_arg(&ep->tp.args[i]);
+
+	return ret;
+}
+
+static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const char *argv[])
+{
+	struct event_filter *dummy = NULL;
+	int i, ret, len = 0;
+	char *p;
+
+	if (argc == 0) {
+		trace_probe_log_err(0, NO_EP_FILTER);
+		return -EINVAL;
+	}
+
+	/* Recover the filter string */
+	for (i = 0; i < argc; i++)
+		len += strlen(argv[i]) + 1;
+
+	ep->filter_str = kzalloc(len, GFP_KERNEL);
+	if (!ep->filter_str)
+		return -ENOMEM;
+
+	p = ep->filter_str;
+	for (i = 0; i < argc; i++) {
+		ret = snprintf(p, len, "%s ", argv[i]);
+		if (ret < 0)
+			goto error;
+		if (ret > len) {
+			ret = -E2BIG;
+			goto error;
+		}
+		p += ret;
+		len -= ret;
+	}
+	p[-1] = '\0';
+
+	/*
+	 * Ensure the filter string can be parsed correctly. Note, this
+	 * filter string is for the original event, not for the eprobe.
+	 */
+	ret = create_event_filter(top_trace_array(), ep->event, ep->filter_str,
+				  true, &dummy);
+	free_event_filter(dummy);
+	if (ret)
+		goto error;
+
+	return 0;
+error:
+	kfree(ep->filter_str);
+	ep->filter_str = NULL;
+	return ret;
+}
+
+static int __trace_eprobe_create(int argc, const char *argv[])
+{
+	/*
+	 * Argument syntax:
+	 *      e[:[GRP/][ENAME]] SYSTEM.EVENT [FETCHARGS] [if FILTER]
+	 * Fetch args (no space):
+	 *  <name>=$<field>[:TYPE]
+	 */
+	const char *event = NULL, *group = EPROBE_EVENT_SYSTEM;
+	const char *sys_event = NULL, *sys_name = NULL;
+	struct trace_event_call *event_call;
+	struct trace_eprobe *ep = NULL;
+	char buf1[MAX_EVENT_NAME_LEN];
+	char buf2[MAX_EVENT_NAME_LEN];
+	char gbuf[MAX_EVENT_NAME_LEN];
+	int ret = 0, filter_idx = 0;
+	int i, filter_cnt;
+
+	if (argc < 2 || argv[0][0] != 'e')
+		return -ECANCELED;
+
+	trace_probe_log_init("event_probe", argc, argv);
+
+	event = strchr(&argv[0][1], ':');
+	if (event) {
+		event++;
+		ret = traceprobe_parse_event_name(&event, &group, gbuf,
+						  event - argv[0]);
+		if (ret)
+			goto parse_error;
+	}
+
+	trace_probe_log_set_index(1);
+	sys_event = argv[1];
+	ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2, 0);
+	if (ret || !sys_event || !sys_name) {
+		trace_probe_log_err(0, NO_EVENT_INFO);
+		goto parse_error;
+	}
+
+	if (!event) {
+		strscpy(buf1, sys_event, MAX_EVENT_NAME_LEN);
+		event = buf1;
+	}
+
+	for (i = 2; i < argc; i++) {
+		if (!strcmp(argv[i], "if")) {
+			filter_idx = i + 1;
+			filter_cnt = argc - filter_idx;
+			argc = i;
+			break;
+		}
+	}
+
+	mutex_lock(&event_mutex);
+	event_call = find_and_get_event(sys_name, sys_event);
+	ep = alloc_event_probe(group, event, event_call, argc - 2);
+	mutex_unlock(&event_mutex);
+
+	if (IS_ERR(ep)) {
+		ret = PTR_ERR(ep);
+		if (ret == -ENODEV)
+			trace_probe_log_err(0, BAD_ATTACH_EVENT);
+		/* This must return -ENOMEM or missing event, else there is a bug */
+		WARN_ON_ONCE(ret != -ENOMEM && ret != -ENODEV);
+		ep = NULL;
+		goto error;
+	}
+
+	if (filter_idx) {
+		trace_probe_log_set_index(filter_idx);
+		ret = trace_eprobe_parse_filter(ep, filter_cnt, argv + filter_idx);
+		if (ret)
+			goto parse_error;
+	} else
+		ep->filter_str = NULL;
+
+	argc -= 2; argv += 2;
+	/* parse arguments */
+	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
+		trace_probe_log_set_index(i + 2);
+		ret = trace_eprobe_tp_update_arg(ep, argv, i);
+		if (ret)
+			goto error;
+	}
+	ret = traceprobe_set_print_fmt(&ep->tp, PROBE_PRINT_EVENT);
+	if (ret < 0)
+		goto error;
+	init_trace_eprobe_call(ep);
+	mutex_lock(&event_mutex);
+	ret = trace_probe_register_event_call(&ep->tp);
+	if (ret) {
+		if (ret == -EEXIST) {
+			trace_probe_log_set_index(0);
+			trace_probe_log_err(0, EVENT_EXIST);
+		}
+		mutex_unlock(&event_mutex);
+		goto error;
+	}
+	ret = dyn_event_add(&ep->devent, &ep->tp.event->call);
+	mutex_unlock(&event_mutex);
+	return ret;
+parse_error:
+	ret = -EINVAL;
+error:
+	trace_event_probe_cleanup(ep);
+	return ret;
+}
+
+/*
+ * Register dynevent at core_initcall. This allows kernel to setup eprobe
+ * events in postcore_initcall without tracefs.
+ */
+static __init int trace_events_eprobe_init_early(void)
+{
+	int err = 0;
+
+	err = dyn_event_register(&eprobe_dyn_event_ops);
+	if (err)
+		pr_warn("Could not register eprobe_dyn_event_ops\n");
+
+	return err;
+}
+core_initcall(trace_events_eprobe_init_early);
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
new file mode 100644
index 000000000..61e3a2620
--- /dev/null
+++ b/kernel/trace/trace_event_perf.c
@@ -0,0 +1,529 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace event based perf event profiling/tracing
+ *
+ * Copyright (C) 2009 Red Hat Inc, Peter Zijlstra
+ * Copyright (C) 2009-2010 Frederic Weisbecker <fweisbec@gmail.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kprobes.h>
+#include <linux/security.h>
+#include "trace.h"
+#include "trace_probe.h"
+
+static char __percpu *perf_trace_buf[PERF_NR_CONTEXTS];
+
+/*
+ * Force it to be aligned to unsigned long to avoid misaligned accesses
+ * surprises
+ */
+typedef typeof(unsigned long [PERF_MAX_TRACE_SIZE / sizeof(unsigned long)])
+	perf_trace_t;
+
+/* Count the events in use (per event id, not per instance) */
+static int	total_ref_count;
+
+static int perf_trace_event_perm(struct trace_event_call *tp_event,
+				 struct perf_event *p_event)
+{
+	int ret;
+
+	if (tp_event->perf_perm) {
+		ret = tp_event->perf_perm(tp_event, p_event);
+		if (ret)
+			return ret;
+	}
+
+	/*
+	 * We checked and allowed to create parent,
+	 * allow children without checking.
+	 */
+	if (p_event->parent)
+		return 0;
+
+	/*
+	 * It's ok to check current process (owner) permissions in here,
+	 * because code below is called only via perf_event_open syscall.
+	 */
+
+	/* The ftrace function trace is allowed only for root. */
+	if (ftrace_event_is_function(tp_event)) {
+		ret = perf_allow_tracepoint(&p_event->attr);
+		if (ret)
+			return ret;
+
+		if (!is_sampling_event(p_event))
+			return 0;
+
+		/*
+		 * We don't allow user space callchains for  function trace
+		 * event, due to issues with page faults while tracing page
+		 * fault handler and its overall trickiness nature.
+		 */
+		if (!p_event->attr.exclude_callchain_user)
+			return -EINVAL;
+
+		/*
+		 * Same reason to disable user stack dump as for user space
+		 * callchains above.
+		 */
+		if (p_event->attr.sample_type & PERF_SAMPLE_STACK_USER)
+			return -EINVAL;
+	}
+
+	/* No tracing, just counting, so no obvious leak */
+	if (!(p_event->attr.sample_type & PERF_SAMPLE_RAW))
+		return 0;
+
+	/* Some events are ok to be traced by non-root users... */
+	if (p_event->attach_state == PERF_ATTACH_TASK) {
+		if (tp_event->flags & TRACE_EVENT_FL_CAP_ANY)
+			return 0;
+	}
+
+	/*
+	 * ...otherwise raw tracepoint data can be a severe data leak,
+	 * only allow root to have these.
+	 */
+	ret = perf_allow_tracepoint(&p_event->attr);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int perf_trace_event_reg(struct trace_event_call *tp_event,
+				struct perf_event *p_event)
+{
+	struct hlist_head __percpu *list;
+	int ret = -ENOMEM;
+	int cpu;
+
+	p_event->tp_event = tp_event;
+	if (tp_event->perf_refcount++ > 0)
+		return 0;
+
+	list = alloc_percpu(struct hlist_head);
+	if (!list)
+		goto fail;
+
+	for_each_possible_cpu(cpu)
+		INIT_HLIST_HEAD(per_cpu_ptr(list, cpu));
+
+	tp_event->perf_events = list;
+
+	if (!total_ref_count) {
+		char __percpu *buf;
+		int i;
+
+		for (i = 0; i < PERF_NR_CONTEXTS; i++) {
+			buf = (char __percpu *)alloc_percpu(perf_trace_t);
+			if (!buf)
+				goto fail;
+
+			perf_trace_buf[i] = buf;
+		}
+	}
+
+	ret = tp_event->class->reg(tp_event, TRACE_REG_PERF_REGISTER, NULL);
+	if (ret)
+		goto fail;
+
+	total_ref_count++;
+	return 0;
+
+fail:
+	if (!total_ref_count) {
+		int i;
+
+		for (i = 0; i < PERF_NR_CONTEXTS; i++) {
+			free_percpu(perf_trace_buf[i]);
+			perf_trace_buf[i] = NULL;
+		}
+	}
+
+	if (!--tp_event->perf_refcount) {
+		free_percpu(tp_event->perf_events);
+		tp_event->perf_events = NULL;
+	}
+
+	return ret;
+}
+
+static void perf_trace_event_unreg(struct perf_event *p_event)
+{
+	struct trace_event_call *tp_event = p_event->tp_event;
+	int i;
+
+	if (--tp_event->perf_refcount > 0)
+		return;
+
+	tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER, NULL);
+
+	/*
+	 * Ensure our callback won't be called anymore. The buffers
+	 * will be freed after that.
+	 */
+	tracepoint_synchronize_unregister();
+
+	free_percpu(tp_event->perf_events);
+	tp_event->perf_events = NULL;
+
+	if (!--total_ref_count) {
+		for (i = 0; i < PERF_NR_CONTEXTS; i++) {
+			free_percpu(perf_trace_buf[i]);
+			perf_trace_buf[i] = NULL;
+		}
+	}
+}
+
+static int perf_trace_event_open(struct perf_event *p_event)
+{
+	struct trace_event_call *tp_event = p_event->tp_event;
+	return tp_event->class->reg(tp_event, TRACE_REG_PERF_OPEN, p_event);
+}
+
+static void perf_trace_event_close(struct perf_event *p_event)
+{
+	struct trace_event_call *tp_event = p_event->tp_event;
+	tp_event->class->reg(tp_event, TRACE_REG_PERF_CLOSE, p_event);
+}
+
+static int perf_trace_event_init(struct trace_event_call *tp_event,
+				 struct perf_event *p_event)
+{
+	int ret;
+
+	ret = perf_trace_event_perm(tp_event, p_event);
+	if (ret)
+		return ret;
+
+	ret = perf_trace_event_reg(tp_event, p_event);
+	if (ret)
+		return ret;
+
+	ret = perf_trace_event_open(p_event);
+	if (ret) {
+		perf_trace_event_unreg(p_event);
+		return ret;
+	}
+
+	return 0;
+}
+
+int perf_trace_init(struct perf_event *p_event)
+{
+	struct trace_event_call *tp_event;
+	u64 event_id = p_event->attr.config;
+	int ret = -EINVAL;
+
+	mutex_lock(&event_mutex);
+	list_for_each_entry(tp_event, &ftrace_events, list) {
+		if (tp_event->event.type == event_id &&
+		    tp_event->class && tp_event->class->reg &&
+		    trace_event_try_get_ref(tp_event)) {
+			ret = perf_trace_event_init(tp_event, p_event);
+			if (ret)
+				trace_event_put_ref(tp_event);
+			break;
+		}
+	}
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+void perf_trace_destroy(struct perf_event *p_event)
+{
+	mutex_lock(&event_mutex);
+	perf_trace_event_close(p_event);
+	perf_trace_event_unreg(p_event);
+	trace_event_put_ref(p_event->tp_event);
+	mutex_unlock(&event_mutex);
+}
+
+#ifdef CONFIG_KPROBE_EVENTS
+int perf_kprobe_init(struct perf_event *p_event, bool is_retprobe)
+{
+	int ret;
+	char *func = NULL;
+	struct trace_event_call *tp_event;
+
+	if (p_event->attr.kprobe_func) {
+		func = kzalloc(KSYM_NAME_LEN, GFP_KERNEL);
+		if (!func)
+			return -ENOMEM;
+		ret = strncpy_from_user(
+			func, u64_to_user_ptr(p_event->attr.kprobe_func),
+			KSYM_NAME_LEN);
+		if (ret == KSYM_NAME_LEN)
+			ret = -E2BIG;
+		if (ret < 0)
+			goto out;
+
+		if (func[0] == '\0') {
+			kfree(func);
+			func = NULL;
+		}
+	}
+
+	tp_event = create_local_trace_kprobe(
+		func, (void *)(unsigned long)(p_event->attr.kprobe_addr),
+		p_event->attr.probe_offset, is_retprobe);
+	if (IS_ERR(tp_event)) {
+		ret = PTR_ERR(tp_event);
+		goto out;
+	}
+
+	mutex_lock(&event_mutex);
+	ret = perf_trace_event_init(tp_event, p_event);
+	if (ret)
+		destroy_local_trace_kprobe(tp_event);
+	mutex_unlock(&event_mutex);
+out:
+	kfree(func);
+	return ret;
+}
+
+void perf_kprobe_destroy(struct perf_event *p_event)
+{
+	mutex_lock(&event_mutex);
+	perf_trace_event_close(p_event);
+	perf_trace_event_unreg(p_event);
+	trace_event_put_ref(p_event->tp_event);
+	mutex_unlock(&event_mutex);
+
+	destroy_local_trace_kprobe(p_event->tp_event);
+}
+#endif /* CONFIG_KPROBE_EVENTS */
+
+#ifdef CONFIG_UPROBE_EVENTS
+int perf_uprobe_init(struct perf_event *p_event,
+		     unsigned long ref_ctr_offset, bool is_retprobe)
+{
+	int ret;
+	char *path = NULL;
+	struct trace_event_call *tp_event;
+
+	if (!p_event->attr.uprobe_path)
+		return -EINVAL;
+
+	path = strndup_user(u64_to_user_ptr(p_event->attr.uprobe_path),
+			    PATH_MAX);
+	if (IS_ERR(path)) {
+		ret = PTR_ERR(path);
+		return (ret == -EINVAL) ? -E2BIG : ret;
+	}
+	if (path[0] == '\0') {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	tp_event = create_local_trace_uprobe(path, p_event->attr.probe_offset,
+					     ref_ctr_offset, is_retprobe);
+	if (IS_ERR(tp_event)) {
+		ret = PTR_ERR(tp_event);
+		goto out;
+	}
+
+	/*
+	 * local trace_uprobe need to hold event_mutex to call
+	 * uprobe_buffer_enable() and uprobe_buffer_disable().
+	 * event_mutex is not required for local trace_kprobes.
+	 */
+	mutex_lock(&event_mutex);
+	ret = perf_trace_event_init(tp_event, p_event);
+	if (ret)
+		destroy_local_trace_uprobe(tp_event);
+	mutex_unlock(&event_mutex);
+out:
+	kfree(path);
+	return ret;
+}
+
+void perf_uprobe_destroy(struct perf_event *p_event)
+{
+	mutex_lock(&event_mutex);
+	perf_trace_event_close(p_event);
+	perf_trace_event_unreg(p_event);
+	trace_event_put_ref(p_event->tp_event);
+	mutex_unlock(&event_mutex);
+	destroy_local_trace_uprobe(p_event->tp_event);
+}
+#endif /* CONFIG_UPROBE_EVENTS */
+
+int perf_trace_add(struct perf_event *p_event, int flags)
+{
+	struct trace_event_call *tp_event = p_event->tp_event;
+
+	if (!(flags & PERF_EF_START))
+		p_event->hw.state = PERF_HES_STOPPED;
+
+	/*
+	 * If TRACE_REG_PERF_ADD returns false; no custom action was performed
+	 * and we need to take the default action of enqueueing our event on
+	 * the right per-cpu hlist.
+	 */
+	if (!tp_event->class->reg(tp_event, TRACE_REG_PERF_ADD, p_event)) {
+		struct hlist_head __percpu *pcpu_list;
+		struct hlist_head *list;
+
+		pcpu_list = tp_event->perf_events;
+		if (WARN_ON_ONCE(!pcpu_list))
+			return -EINVAL;
+
+		list = this_cpu_ptr(pcpu_list);
+		hlist_add_head_rcu(&p_event->hlist_entry, list);
+	}
+
+	return 0;
+}
+
+void perf_trace_del(struct perf_event *p_event, int flags)
+{
+	struct trace_event_call *tp_event = p_event->tp_event;
+
+	/*
+	 * If TRACE_REG_PERF_DEL returns false; no custom action was performed
+	 * and we need to take the default action of dequeueing our event from
+	 * the right per-cpu hlist.
+	 */
+	if (!tp_event->class->reg(tp_event, TRACE_REG_PERF_DEL, p_event))
+		hlist_del_rcu(&p_event->hlist_entry);
+}
+
+void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp)
+{
+	char *raw_data;
+	int rctx;
+
+	BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long));
+
+	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
+		      "perf buffer not large enough, wanted %d, have %d",
+		      size, PERF_MAX_TRACE_SIZE))
+		return NULL;
+
+	*rctxp = rctx = perf_swevent_get_recursion_context();
+	if (rctx < 0)
+		return NULL;
+
+	if (regs)
+		*regs = this_cpu_ptr(&__perf_regs[rctx]);
+	raw_data = this_cpu_ptr(perf_trace_buf[rctx]);
+
+	/* zero the dead bytes from align to not leak stack to user */
+	memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64));
+	return raw_data;
+}
+EXPORT_SYMBOL_GPL(perf_trace_buf_alloc);
+NOKPROBE_SYMBOL(perf_trace_buf_alloc);
+
+void perf_trace_buf_update(void *record, u16 type)
+{
+	struct trace_entry *entry = record;
+
+	tracing_generic_entry_update(entry, type, tracing_gen_ctx());
+}
+NOKPROBE_SYMBOL(perf_trace_buf_update);
+
+#ifdef CONFIG_FUNCTION_TRACER
+static void
+perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip,
+			  struct ftrace_ops *ops,  struct ftrace_regs *fregs)
+{
+	struct ftrace_entry *entry;
+	struct perf_event *event;
+	struct hlist_head head;
+	struct pt_regs regs;
+	int rctx;
+	int bit;
+
+	if (!rcu_is_watching())
+		return;
+
+	bit = ftrace_test_recursion_trylock(ip, parent_ip);
+	if (bit < 0)
+		return;
+
+	if ((unsigned long)ops->private != smp_processor_id())
+		goto out;
+
+	event = container_of(ops, struct perf_event, ftrace_ops);
+
+	/*
+	 * @event->hlist entry is NULL (per INIT_HLIST_NODE), and all
+	 * the perf code does is hlist_for_each_entry_rcu(), so we can
+	 * get away with simply setting the @head.first pointer in order
+	 * to create a singular list.
+	 */
+	head.first = &event->hlist_entry;
+
+#define ENTRY_SIZE (ALIGN(sizeof(struct ftrace_entry) + sizeof(u32), \
+		    sizeof(u64)) - sizeof(u32))
+
+	BUILD_BUG_ON(ENTRY_SIZE > PERF_MAX_TRACE_SIZE);
+
+	memset(&regs, 0, sizeof(regs));
+	perf_fetch_caller_regs(&regs);
+
+	entry = perf_trace_buf_alloc(ENTRY_SIZE, NULL, &rctx);
+	if (!entry)
+		goto out;
+
+	entry->ip = ip;
+	entry->parent_ip = parent_ip;
+	perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, TRACE_FN,
+			      1, &regs, &head, NULL);
+
+out:
+	ftrace_test_recursion_unlock(bit);
+#undef ENTRY_SIZE
+}
+
+static int perf_ftrace_function_register(struct perf_event *event)
+{
+	struct ftrace_ops *ops = &event->ftrace_ops;
+
+	ops->func    = perf_ftrace_function_call;
+	ops->private = (void *)(unsigned long)nr_cpu_ids;
+
+	return register_ftrace_function(ops);
+}
+
+static int perf_ftrace_function_unregister(struct perf_event *event)
+{
+	struct ftrace_ops *ops = &event->ftrace_ops;
+	int ret = unregister_ftrace_function(ops);
+	ftrace_free_filter(ops);
+	return ret;
+}
+
+int perf_ftrace_event_register(struct trace_event_call *call,
+			       enum trace_reg type, void *data)
+{
+	struct perf_event *event = data;
+
+	switch (type) {
+	case TRACE_REG_REGISTER:
+	case TRACE_REG_UNREGISTER:
+		break;
+	case TRACE_REG_PERF_REGISTER:
+	case TRACE_REG_PERF_UNREGISTER:
+		return 0;
+	case TRACE_REG_PERF_OPEN:
+		return perf_ftrace_function_register(data);
+	case TRACE_REG_PERF_CLOSE:
+		return perf_ftrace_function_unregister(data);
+	case TRACE_REG_PERF_ADD:
+		event->ftrace_ops.private = (void *)(unsigned long)smp_processor_id();
+		return 1;
+	case TRACE_REG_PERF_DEL:
+		event->ftrace_ops.private = (void *)(unsigned long)nr_cpu_ids;
+		return 1;
+	}
+
+	return -EINVAL;
+}
+#endif /* CONFIG_FUNCTION_TRACER */
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
new file mode 100644
index 000000000..a6d2f99f8
--- /dev/null
+++ b/kernel/trace/trace_events.c
@@ -0,0 +1,4108 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * event tracer
+ *
+ * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ *  - Added format output of fields of the trace point.
+ *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
+ *
+ */
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/workqueue.h>
+#include <linux/security.h>
+#include <linux/spinlock.h>
+#include <linux/kthread.h>
+#include <linux/tracefs.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/sort.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+
+#include <trace/events/sched.h>
+#include <trace/syscall.h>
+
+#include <asm/setup.h>
+
+#include "trace_output.h"
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM "TRACE_SYSTEM"
+
+DEFINE_MUTEX(event_mutex);
+
+LIST_HEAD(ftrace_events);
+static LIST_HEAD(ftrace_generic_fields);
+static LIST_HEAD(ftrace_common_fields);
+static bool eventdir_initialized;
+
+static LIST_HEAD(module_strings);
+
+struct module_string {
+	struct list_head	next;
+	struct module		*module;
+	char			*str;
+};
+
+#define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
+
+static struct kmem_cache *field_cachep;
+static struct kmem_cache *file_cachep;
+
+static inline int system_refcount(struct event_subsystem *system)
+{
+	return system->ref_count;
+}
+
+static int system_refcount_inc(struct event_subsystem *system)
+{
+	return system->ref_count++;
+}
+
+static int system_refcount_dec(struct event_subsystem *system)
+{
+	return --system->ref_count;
+}
+
+/* Double loops, do not use break, only goto's work */
+#define do_for_each_event_file(tr, file)			\
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {	\
+		list_for_each_entry(file, &tr->events, list)
+
+#define do_for_each_event_file_safe(tr, file)			\
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {	\
+		struct trace_event_file *___n;				\
+		list_for_each_entry_safe(file, ___n, &tr->events, list)
+
+#define while_for_each_event_file()		\
+	}
+
+static struct ftrace_event_field *
+__find_event_field(struct list_head *head, char *name)
+{
+	struct ftrace_event_field *field;
+
+	list_for_each_entry(field, head, link) {
+		if (!strcmp(field->name, name))
+			return field;
+	}
+
+	return NULL;
+}
+
+struct ftrace_event_field *
+trace_find_event_field(struct trace_event_call *call, char *name)
+{
+	struct ftrace_event_field *field;
+	struct list_head *head;
+
+	head = trace_get_fields(call);
+	field = __find_event_field(head, name);
+	if (field)
+		return field;
+
+	field = __find_event_field(&ftrace_generic_fields, name);
+	if (field)
+		return field;
+
+	return __find_event_field(&ftrace_common_fields, name);
+}
+
+static int __trace_define_field(struct list_head *head, const char *type,
+				const char *name, int offset, int size,
+				int is_signed, int filter_type, int len)
+{
+	struct ftrace_event_field *field;
+
+	field = kmem_cache_alloc(field_cachep, GFP_TRACE);
+	if (!field)
+		return -ENOMEM;
+
+	field->name = name;
+	field->type = type;
+
+	if (filter_type == FILTER_OTHER)
+		field->filter_type = filter_assign_type(type);
+	else
+		field->filter_type = filter_type;
+
+	field->offset = offset;
+	field->size = size;
+	field->is_signed = is_signed;
+	field->len = len;
+
+	list_add(&field->link, head);
+
+	return 0;
+}
+
+int trace_define_field(struct trace_event_call *call, const char *type,
+		       const char *name, int offset, int size, int is_signed,
+		       int filter_type)
+{
+	struct list_head *head;
+
+	if (WARN_ON(!call->class))
+		return 0;
+
+	head = trace_get_fields(call);
+	return __trace_define_field(head, type, name, offset, size,
+				    is_signed, filter_type, 0);
+}
+EXPORT_SYMBOL_GPL(trace_define_field);
+
+static int trace_define_field_ext(struct trace_event_call *call, const char *type,
+		       const char *name, int offset, int size, int is_signed,
+		       int filter_type, int len)
+{
+	struct list_head *head;
+
+	if (WARN_ON(!call->class))
+		return 0;
+
+	head = trace_get_fields(call);
+	return __trace_define_field(head, type, name, offset, size,
+				    is_signed, filter_type, len);
+}
+
+#define __generic_field(type, item, filter_type)			\
+	ret = __trace_define_field(&ftrace_generic_fields, #type,	\
+				   #item, 0, 0, is_signed_type(type),	\
+				   filter_type, 0);			\
+	if (ret)							\
+		return ret;
+
+#define __common_field(type, item)					\
+	ret = __trace_define_field(&ftrace_common_fields, #type,	\
+				   "common_" #item,			\
+				   offsetof(typeof(ent), item),		\
+				   sizeof(ent.item),			\
+				   is_signed_type(type), FILTER_OTHER, 0);	\
+	if (ret)							\
+		return ret;
+
+static int trace_define_generic_fields(void)
+{
+	int ret;
+
+	__generic_field(int, CPU, FILTER_CPU);
+	__generic_field(int, cpu, FILTER_CPU);
+	__generic_field(int, common_cpu, FILTER_CPU);
+	__generic_field(char *, COMM, FILTER_COMM);
+	__generic_field(char *, comm, FILTER_COMM);
+
+	return ret;
+}
+
+static int trace_define_common_fields(void)
+{
+	int ret;
+	struct trace_entry ent;
+
+	__common_field(unsigned short, type);
+	__common_field(unsigned char, flags);
+	/* Holds both preempt_count and migrate_disable */
+	__common_field(unsigned char, preempt_count);
+	__common_field(int, pid);
+
+	return ret;
+}
+
+static void trace_destroy_fields(struct trace_event_call *call)
+{
+	struct ftrace_event_field *field, *next;
+	struct list_head *head;
+
+	head = trace_get_fields(call);
+	list_for_each_entry_safe(field, next, head, link) {
+		list_del(&field->link);
+		kmem_cache_free(field_cachep, field);
+	}
+}
+
+/*
+ * run-time version of trace_event_get_offsets_<call>() that returns the last
+ * accessible offset of trace fields excluding __dynamic_array bytes
+ */
+int trace_event_get_offsets(struct trace_event_call *call)
+{
+	struct ftrace_event_field *tail;
+	struct list_head *head;
+
+	head = trace_get_fields(call);
+	/*
+	 * head->next points to the last field with the largest offset,
+	 * since it was added last by trace_define_field()
+	 */
+	tail = list_first_entry(head, struct ftrace_event_field, link);
+	return tail->offset + tail->size;
+}
+
+/*
+ * Check if the referenced field is an array and return true,
+ * as arrays are OK to dereference.
+ */
+static bool test_field(const char *fmt, struct trace_event_call *call)
+{
+	struct trace_event_fields *field = call->class->fields_array;
+	const char *array_descriptor;
+	const char *p = fmt;
+	int len;
+
+	if (!(len = str_has_prefix(fmt, "REC->")))
+		return false;
+	fmt += len;
+	for (p = fmt; *p; p++) {
+		if (!isalnum(*p) && *p != '_')
+			break;
+	}
+	len = p - fmt;
+
+	for (; field->type; field++) {
+		if (strncmp(field->name, fmt, len) ||
+		    field->name[len])
+			continue;
+		array_descriptor = strchr(field->type, '[');
+		/* This is an array and is OK to dereference. */
+		return array_descriptor != NULL;
+	}
+	return false;
+}
+
+/*
+ * Examine the print fmt of the event looking for unsafe dereference
+ * pointers using %p* that could be recorded in the trace event and
+ * much later referenced after the pointer was freed. Dereferencing
+ * pointers are OK, if it is dereferenced into the event itself.
+ */
+static void test_event_printk(struct trace_event_call *call)
+{
+	u64 dereference_flags = 0;
+	bool first = true;
+	const char *fmt, *c, *r, *a;
+	int parens = 0;
+	char in_quote = 0;
+	int start_arg = 0;
+	int arg = 0;
+	int i;
+
+	fmt = call->print_fmt;
+
+	if (!fmt)
+		return;
+
+	for (i = 0; fmt[i]; i++) {
+		switch (fmt[i]) {
+		case '\\':
+			i++;
+			if (!fmt[i])
+				return;
+			continue;
+		case '"':
+		case '\'':
+			/*
+			 * The print fmt starts with a string that
+			 * is processed first to find %p* usage,
+			 * then after the first string, the print fmt
+			 * contains arguments that are used to check
+			 * if the dereferenced %p* usage is safe.
+			 */
+			if (first) {
+				if (fmt[i] == '\'')
+					continue;
+				if (in_quote) {
+					arg = 0;
+					first = false;
+					/*
+					 * If there was no %p* uses
+					 * the fmt is OK.
+					 */
+					if (!dereference_flags)
+						return;
+				}
+			}
+			if (in_quote) {
+				if (in_quote == fmt[i])
+					in_quote = 0;
+			} else {
+				in_quote = fmt[i];
+			}
+			continue;
+		case '%':
+			if (!first || !in_quote)
+				continue;
+			i++;
+			if (!fmt[i])
+				return;
+			switch (fmt[i]) {
+			case '%':
+				continue;
+			case 'p':
+				/* Find dereferencing fields */
+				switch (fmt[i + 1]) {
+				case 'B': case 'R': case 'r':
+				case 'b': case 'M': case 'm':
+				case 'I': case 'i': case 'E':
+				case 'U': case 'V': case 'N':
+				case 'a': case 'd': case 'D':
+				case 'g': case 't': case 'C':
+				case 'O': case 'f':
+					if (WARN_ONCE(arg == 63,
+						      "Too many args for event: %s",
+						      trace_event_name(call)))
+						return;
+					dereference_flags |= 1ULL << arg;
+				}
+				break;
+			default:
+			{
+				bool star = false;
+				int j;
+
+				/* Increment arg if %*s exists. */
+				for (j = 0; fmt[i + j]; j++) {
+					if (isdigit(fmt[i + j]) ||
+					    fmt[i + j] == '.')
+						continue;
+					if (fmt[i + j] == '*') {
+						star = true;
+						continue;
+					}
+					if ((fmt[i + j] == 's') && star)
+						arg++;
+					break;
+				}
+				break;
+			} /* default */
+
+			} /* switch */
+			arg++;
+			continue;
+		case '(':
+			if (in_quote)
+				continue;
+			parens++;
+			continue;
+		case ')':
+			if (in_quote)
+				continue;
+			parens--;
+			if (WARN_ONCE(parens < 0,
+				      "Paren mismatch for event: %s\narg='%s'\n%*s",
+				      trace_event_name(call),
+				      fmt + start_arg,
+				      (i - start_arg) + 5, "^"))
+				return;
+			continue;
+		case ',':
+			if (in_quote || parens)
+				continue;
+			i++;
+			while (isspace(fmt[i]))
+				i++;
+			start_arg = i;
+			if (!(dereference_flags & (1ULL << arg)))
+				goto next_arg;
+
+			/* Find the REC-> in the argument */
+			c = strchr(fmt + i, ',');
+			r = strstr(fmt + i, "REC->");
+			if (r && (!c || r < c)) {
+				/*
+				 * Addresses of events on the buffer,
+				 * or an array on the buffer is
+				 * OK to dereference.
+				 * There's ways to fool this, but
+				 * this is to catch common mistakes,
+				 * not malicious code.
+				 */
+				a = strchr(fmt + i, '&');
+				if ((a && (a < r)) || test_field(r, call))
+					dereference_flags &= ~(1ULL << arg);
+			} else if ((r = strstr(fmt + i, "__get_dynamic_array(")) &&
+				   (!c || r < c)) {
+				dereference_flags &= ~(1ULL << arg);
+			} else if ((r = strstr(fmt + i, "__get_sockaddr(")) &&
+				   (!c || r < c)) {
+				dereference_flags &= ~(1ULL << arg);
+			}
+
+		next_arg:
+			i--;
+			arg++;
+		}
+	}
+
+	/*
+	 * If you triggered the below warning, the trace event reported
+	 * uses an unsafe dereference pointer %p*. As the data stored
+	 * at the trace event time may no longer exist when the trace
+	 * event is printed, dereferencing to the original source is
+	 * unsafe. The source of the dereference must be copied into the
+	 * event itself, and the dereference must access the copy instead.
+	 */
+	if (WARN_ON_ONCE(dereference_flags)) {
+		arg = 1;
+		while (!(dereference_flags & 1)) {
+			dereference_flags >>= 1;
+			arg++;
+		}
+		pr_warn("event %s has unsafe dereference of argument %d\n",
+			trace_event_name(call), arg);
+		pr_warn("print_fmt: %s\n", fmt);
+	}
+}
+
+int trace_event_raw_init(struct trace_event_call *call)
+{
+	int id;
+
+	id = register_trace_event(&call->event);
+	if (!id)
+		return -ENODEV;
+
+	test_event_printk(call);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(trace_event_raw_init);
+
+bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
+{
+	struct trace_array *tr = trace_file->tr;
+	struct trace_array_cpu *data;
+	struct trace_pid_list *no_pid_list;
+	struct trace_pid_list *pid_list;
+
+	pid_list = rcu_dereference_raw(tr->filtered_pids);
+	no_pid_list = rcu_dereference_raw(tr->filtered_no_pids);
+
+	if (!pid_list && !no_pid_list)
+		return false;
+
+	data = this_cpu_ptr(tr->array_buffer.data);
+
+	return data->ignore_pid;
+}
+EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
+
+void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
+				 struct trace_event_file *trace_file,
+				 unsigned long len)
+{
+	struct trace_event_call *event_call = trace_file->event_call;
+
+	if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
+	    trace_event_ignore_this_pid(trace_file))
+		return NULL;
+
+	/*
+	 * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
+	 * preemption (adding one to the preempt_count). Since we are
+	 * interested in the preempt_count at the time the tracepoint was
+	 * hit, we need to subtract one to offset the increment.
+	 */
+	fbuffer->trace_ctx = tracing_gen_ctx_dec();
+	fbuffer->trace_file = trace_file;
+
+	fbuffer->event =
+		trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
+						event_call->event.type, len,
+						fbuffer->trace_ctx);
+	if (!fbuffer->event)
+		return NULL;
+
+	fbuffer->regs = NULL;
+	fbuffer->entry = ring_buffer_event_data(fbuffer->event);
+	return fbuffer->entry;
+}
+EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
+
+int trace_event_reg(struct trace_event_call *call,
+		    enum trace_reg type, void *data)
+{
+	struct trace_event_file *file = data;
+
+	WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
+	switch (type) {
+	case TRACE_REG_REGISTER:
+		return tracepoint_probe_register(call->tp,
+						 call->class->probe,
+						 file);
+	case TRACE_REG_UNREGISTER:
+		tracepoint_probe_unregister(call->tp,
+					    call->class->probe,
+					    file);
+		return 0;
+
+#ifdef CONFIG_PERF_EVENTS
+	case TRACE_REG_PERF_REGISTER:
+		return tracepoint_probe_register(call->tp,
+						 call->class->perf_probe,
+						 call);
+	case TRACE_REG_PERF_UNREGISTER:
+		tracepoint_probe_unregister(call->tp,
+					    call->class->perf_probe,
+					    call);
+		return 0;
+	case TRACE_REG_PERF_OPEN:
+	case TRACE_REG_PERF_CLOSE:
+	case TRACE_REG_PERF_ADD:
+	case TRACE_REG_PERF_DEL:
+		return 0;
+#endif
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(trace_event_reg);
+
+void trace_event_enable_cmd_record(bool enable)
+{
+	struct trace_event_file *file;
+	struct trace_array *tr;
+
+	lockdep_assert_held(&event_mutex);
+
+	do_for_each_event_file(tr, file) {
+
+		if (!(file->flags & EVENT_FILE_FL_ENABLED))
+			continue;
+
+		if (enable) {
+			tracing_start_cmdline_record();
+			set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
+		} else {
+			tracing_stop_cmdline_record();
+			clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
+		}
+	} while_for_each_event_file();
+}
+
+void trace_event_enable_tgid_record(bool enable)
+{
+	struct trace_event_file *file;
+	struct trace_array *tr;
+
+	lockdep_assert_held(&event_mutex);
+
+	do_for_each_event_file(tr, file) {
+		if (!(file->flags & EVENT_FILE_FL_ENABLED))
+			continue;
+
+		if (enable) {
+			tracing_start_tgid_record();
+			set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
+		} else {
+			tracing_stop_tgid_record();
+			clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
+				  &file->flags);
+		}
+	} while_for_each_event_file();
+}
+
+static int __ftrace_event_enable_disable(struct trace_event_file *file,
+					 int enable, int soft_disable)
+{
+	struct trace_event_call *call = file->event_call;
+	struct trace_array *tr = file->tr;
+	int ret = 0;
+	int disable;
+
+	switch (enable) {
+	case 0:
+		/*
+		 * When soft_disable is set and enable is cleared, the sm_ref
+		 * reference counter is decremented. If it reaches 0, we want
+		 * to clear the SOFT_DISABLED flag but leave the event in the
+		 * state that it was. That is, if the event was enabled and
+		 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
+		 * is set we do not want the event to be enabled before we
+		 * clear the bit.
+		 *
+		 * When soft_disable is not set but the SOFT_MODE flag is,
+		 * we do nothing. Do not disable the tracepoint, otherwise
+		 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
+		 */
+		if (soft_disable) {
+			if (atomic_dec_return(&file->sm_ref) > 0)
+				break;
+			disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
+			clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
+			/* Disable use of trace_buffered_event */
+			trace_buffered_event_disable();
+		} else
+			disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
+
+		if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
+			clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
+			if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
+				tracing_stop_cmdline_record();
+				clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
+			}
+
+			if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
+				tracing_stop_tgid_record();
+				clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
+			}
+
+			call->class->reg(call, TRACE_REG_UNREGISTER, file);
+		}
+		/* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
+		if (file->flags & EVENT_FILE_FL_SOFT_MODE)
+			set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
+		else
+			clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
+		break;
+	case 1:
+		/*
+		 * When soft_disable is set and enable is set, we want to
+		 * register the tracepoint for the event, but leave the event
+		 * as is. That means, if the event was already enabled, we do
+		 * nothing (but set SOFT_MODE). If the event is disabled, we
+		 * set SOFT_DISABLED before enabling the event tracepoint, so
+		 * it still seems to be disabled.
+		 */
+		if (!soft_disable)
+			clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
+		else {
+			if (atomic_inc_return(&file->sm_ref) > 1)
+				break;
+			set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
+			/* Enable use of trace_buffered_event */
+			trace_buffered_event_enable();
+		}
+
+		if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
+			bool cmd = false, tgid = false;
+
+			/* Keep the event disabled, when going to SOFT_MODE. */
+			if (soft_disable)
+				set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
+
+			if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
+				cmd = true;
+				tracing_start_cmdline_record();
+				set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
+			}
+
+			if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
+				tgid = true;
+				tracing_start_tgid_record();
+				set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
+			}
+
+			ret = call->class->reg(call, TRACE_REG_REGISTER, file);
+			if (ret) {
+				if (cmd)
+					tracing_stop_cmdline_record();
+				if (tgid)
+					tracing_stop_tgid_record();
+				pr_info("event trace: Could not enable event "
+					"%s\n", trace_event_name(call));
+				break;
+			}
+			set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
+
+			/* WAS_ENABLED gets set but never cleared. */
+			set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
+		}
+		break;
+	}
+
+	return ret;
+}
+
+int trace_event_enable_disable(struct trace_event_file *file,
+			       int enable, int soft_disable)
+{
+	return __ftrace_event_enable_disable(file, enable, soft_disable);
+}
+
+static int ftrace_event_enable_disable(struct trace_event_file *file,
+				       int enable)
+{
+	return __ftrace_event_enable_disable(file, enable, 0);
+}
+
+static void ftrace_clear_events(struct trace_array *tr)
+{
+	struct trace_event_file *file;
+
+	mutex_lock(&event_mutex);
+	list_for_each_entry(file, &tr->events, list) {
+		ftrace_event_enable_disable(file, 0);
+	}
+	mutex_unlock(&event_mutex);
+}
+
+static void
+event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_array *tr = data;
+
+	pid_list = rcu_dereference_raw(tr->filtered_pids);
+	trace_filter_add_remove_task(pid_list, NULL, task);
+
+	pid_list = rcu_dereference_raw(tr->filtered_no_pids);
+	trace_filter_add_remove_task(pid_list, NULL, task);
+}
+
+static void
+event_filter_pid_sched_process_fork(void *data,
+				    struct task_struct *self,
+				    struct task_struct *task)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_array *tr = data;
+
+	pid_list = rcu_dereference_sched(tr->filtered_pids);
+	trace_filter_add_remove_task(pid_list, self, task);
+
+	pid_list = rcu_dereference_sched(tr->filtered_no_pids);
+	trace_filter_add_remove_task(pid_list, self, task);
+}
+
+void trace_event_follow_fork(struct trace_array *tr, bool enable)
+{
+	if (enable) {
+		register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
+						       tr, INT_MIN);
+		register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit,
+						       tr, INT_MAX);
+	} else {
+		unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
+						    tr);
+		unregister_trace_sched_process_free(event_filter_pid_sched_process_exit,
+						    tr);
+	}
+}
+
+static void
+event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
+					struct task_struct *prev,
+					struct task_struct *next,
+					unsigned int prev_state)
+{
+	struct trace_array *tr = data;
+	struct trace_pid_list *no_pid_list;
+	struct trace_pid_list *pid_list;
+	bool ret;
+
+	pid_list = rcu_dereference_sched(tr->filtered_pids);
+	no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
+
+	/*
+	 * Sched switch is funny, as we only want to ignore it
+	 * in the notrace case if both prev and next should be ignored.
+	 */
+	ret = trace_ignore_this_task(NULL, no_pid_list, prev) &&
+		trace_ignore_this_task(NULL, no_pid_list, next);
+
+	this_cpu_write(tr->array_buffer.data->ignore_pid, ret ||
+		       (trace_ignore_this_task(pid_list, NULL, prev) &&
+			trace_ignore_this_task(pid_list, NULL, next)));
+}
+
+static void
+event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
+					 struct task_struct *prev,
+					 struct task_struct *next,
+					 unsigned int prev_state)
+{
+	struct trace_array *tr = data;
+	struct trace_pid_list *no_pid_list;
+	struct trace_pid_list *pid_list;
+
+	pid_list = rcu_dereference_sched(tr->filtered_pids);
+	no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
+
+	this_cpu_write(tr->array_buffer.data->ignore_pid,
+		       trace_ignore_this_task(pid_list, no_pid_list, next));
+}
+
+static void
+event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
+{
+	struct trace_array *tr = data;
+	struct trace_pid_list *no_pid_list;
+	struct trace_pid_list *pid_list;
+
+	/* Nothing to do if we are already tracing */
+	if (!this_cpu_read(tr->array_buffer.data->ignore_pid))
+		return;
+
+	pid_list = rcu_dereference_sched(tr->filtered_pids);
+	no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
+
+	this_cpu_write(tr->array_buffer.data->ignore_pid,
+		       trace_ignore_this_task(pid_list, no_pid_list, task));
+}
+
+static void
+event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
+{
+	struct trace_array *tr = data;
+	struct trace_pid_list *no_pid_list;
+	struct trace_pid_list *pid_list;
+
+	/* Nothing to do if we are not tracing */
+	if (this_cpu_read(tr->array_buffer.data->ignore_pid))
+		return;
+
+	pid_list = rcu_dereference_sched(tr->filtered_pids);
+	no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
+
+	/* Set tracing if current is enabled */
+	this_cpu_write(tr->array_buffer.data->ignore_pid,
+		       trace_ignore_this_task(pid_list, no_pid_list, current));
+}
+
+static void unregister_pid_events(struct trace_array *tr)
+{
+	unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
+	unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
+
+	unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
+	unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
+
+	unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
+	unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
+
+	unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
+	unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
+}
+
+static void __ftrace_clear_event_pids(struct trace_array *tr, int type)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_pid_list *no_pid_list;
+	struct trace_event_file *file;
+	int cpu;
+
+	pid_list = rcu_dereference_protected(tr->filtered_pids,
+					     lockdep_is_held(&event_mutex));
+	no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
+					     lockdep_is_held(&event_mutex));
+
+	/* Make sure there's something to do */
+	if (!pid_type_enabled(type, pid_list, no_pid_list))
+		return;
+
+	if (!still_need_pid_events(type, pid_list, no_pid_list)) {
+		unregister_pid_events(tr);
+
+		list_for_each_entry(file, &tr->events, list) {
+			clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
+		}
+
+		for_each_possible_cpu(cpu)
+			per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
+	}
+
+	if (type & TRACE_PIDS)
+		rcu_assign_pointer(tr->filtered_pids, NULL);
+
+	if (type & TRACE_NO_PIDS)
+		rcu_assign_pointer(tr->filtered_no_pids, NULL);
+
+	/* Wait till all users are no longer using pid filtering */
+	tracepoint_synchronize_unregister();
+
+	if ((type & TRACE_PIDS) && pid_list)
+		trace_pid_list_free(pid_list);
+
+	if ((type & TRACE_NO_PIDS) && no_pid_list)
+		trace_pid_list_free(no_pid_list);
+}
+
+static void ftrace_clear_event_pids(struct trace_array *tr, int type)
+{
+	mutex_lock(&event_mutex);
+	__ftrace_clear_event_pids(tr, type);
+	mutex_unlock(&event_mutex);
+}
+
+static void __put_system(struct event_subsystem *system)
+{
+	struct event_filter *filter = system->filter;
+
+	WARN_ON_ONCE(system_refcount(system) == 0);
+	if (system_refcount_dec(system))
+		return;
+
+	list_del(&system->list);
+
+	if (filter) {
+		kfree(filter->filter_string);
+		kfree(filter);
+	}
+	kfree_const(system->name);
+	kfree(system);
+}
+
+static void __get_system(struct event_subsystem *system)
+{
+	WARN_ON_ONCE(system_refcount(system) == 0);
+	system_refcount_inc(system);
+}
+
+static void __get_system_dir(struct trace_subsystem_dir *dir)
+{
+	WARN_ON_ONCE(dir->ref_count == 0);
+	dir->ref_count++;
+	__get_system(dir->subsystem);
+}
+
+static void __put_system_dir(struct trace_subsystem_dir *dir)
+{
+	WARN_ON_ONCE(dir->ref_count == 0);
+	/* If the subsystem is about to be freed, the dir must be too */
+	WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
+
+	__put_system(dir->subsystem);
+	if (!--dir->ref_count)
+		kfree(dir);
+}
+
+static void put_system(struct trace_subsystem_dir *dir)
+{
+	mutex_lock(&event_mutex);
+	__put_system_dir(dir);
+	mutex_unlock(&event_mutex);
+}
+
+static void remove_subsystem(struct trace_subsystem_dir *dir)
+{
+	if (!dir)
+		return;
+
+	if (!--dir->nr_events) {
+		tracefs_remove(dir->entry);
+		list_del(&dir->list);
+		__put_system_dir(dir);
+	}
+}
+
+void event_file_get(struct trace_event_file *file)
+{
+	atomic_inc(&file->ref);
+}
+
+void event_file_put(struct trace_event_file *file)
+{
+	if (WARN_ON_ONCE(!atomic_read(&file->ref))) {
+		if (file->flags & EVENT_FILE_FL_FREED)
+			kmem_cache_free(file_cachep, file);
+		return;
+	}
+
+	if (atomic_dec_and_test(&file->ref)) {
+		/* Count should only go to zero when it is freed */
+		if (WARN_ON_ONCE(!(file->flags & EVENT_FILE_FL_FREED)))
+			return;
+		kmem_cache_free(file_cachep, file);
+	}
+}
+
+static void remove_event_file_dir(struct trace_event_file *file)
+{
+	struct dentry *dir = file->dir;
+
+	tracefs_remove(dir);
+
+	list_del(&file->list);
+	remove_subsystem(file->system);
+	free_event_filter(file->filter);
+	file->flags |= EVENT_FILE_FL_FREED;
+	event_file_put(file);
+}
+
+/*
+ * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
+ */
+static int
+__ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
+			      const char *sub, const char *event, int set)
+{
+	struct trace_event_file *file;
+	struct trace_event_call *call;
+	const char *name;
+	int ret = -EINVAL;
+	int eret = 0;
+
+	list_for_each_entry(file, &tr->events, list) {
+
+		call = file->event_call;
+		name = trace_event_name(call);
+
+		if (!name || !call->class || !call->class->reg)
+			continue;
+
+		if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
+			continue;
+
+		if (match &&
+		    strcmp(match, name) != 0 &&
+		    strcmp(match, call->class->system) != 0)
+			continue;
+
+		if (sub && strcmp(sub, call->class->system) != 0)
+			continue;
+
+		if (event && strcmp(event, name) != 0)
+			continue;
+
+		ret = ftrace_event_enable_disable(file, set);
+
+		/*
+		 * Save the first error and return that. Some events
+		 * may still have been enabled, but let the user
+		 * know that something went wrong.
+		 */
+		if (ret && !eret)
+			eret = ret;
+
+		ret = eret;
+	}
+
+	return ret;
+}
+
+static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
+				  const char *sub, const char *event, int set)
+{
+	int ret;
+
+	mutex_lock(&event_mutex);
+	ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
+{
+	char *event = NULL, *sub = NULL, *match;
+	int ret;
+
+	if (!tr)
+		return -ENOENT;
+	/*
+	 * The buf format can be <subsystem>:<event-name>
+	 *  *:<event-name> means any event by that name.
+	 *  :<event-name> is the same.
+	 *
+	 *  <subsystem>:* means all events in that subsystem
+	 *  <subsystem>: means the same.
+	 *
+	 *  <name> (no ':') means all events in a subsystem with
+	 *  the name <name> or any event that matches <name>
+	 */
+
+	match = strsep(&buf, ":");
+	if (buf) {
+		sub = match;
+		event = buf;
+		match = NULL;
+
+		if (!strlen(sub) || strcmp(sub, "*") == 0)
+			sub = NULL;
+		if (!strlen(event) || strcmp(event, "*") == 0)
+			event = NULL;
+	}
+
+	ret = __ftrace_set_clr_event(tr, match, sub, event, set);
+
+	/* Put back the colon to allow this to be called again */
+	if (buf)
+		*(buf - 1) = ':';
+
+	return ret;
+}
+
+/**
+ * trace_set_clr_event - enable or disable an event
+ * @system: system name to match (NULL for any system)
+ * @event: event name to match (NULL for all events, within system)
+ * @set: 1 to enable, 0 to disable
+ *
+ * This is a way for other parts of the kernel to enable or disable
+ * event recording.
+ *
+ * Returns 0 on success, -EINVAL if the parameters do not match any
+ * registered events.
+ */
+int trace_set_clr_event(const char *system, const char *event, int set)
+{
+	struct trace_array *tr = top_trace_array();
+
+	if (!tr)
+		return -ENODEV;
+
+	return __ftrace_set_clr_event(tr, NULL, system, event, set);
+}
+EXPORT_SYMBOL_GPL(trace_set_clr_event);
+
+/**
+ * trace_array_set_clr_event - enable or disable an event for a trace array.
+ * @tr: concerned trace array.
+ * @system: system name to match (NULL for any system)
+ * @event: event name to match (NULL for all events, within system)
+ * @enable: true to enable, false to disable
+ *
+ * This is a way for other parts of the kernel to enable or disable
+ * event recording.
+ *
+ * Returns 0 on success, -EINVAL if the parameters do not match any
+ * registered events.
+ */
+int trace_array_set_clr_event(struct trace_array *tr, const char *system,
+		const char *event, bool enable)
+{
+	int set;
+
+	if (!tr)
+		return -ENOENT;
+
+	set = (enable == true) ? 1 : 0;
+	return __ftrace_set_clr_event(tr, NULL, system, event, set);
+}
+EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
+
+/* 128 should be much more than enough */
+#define EVENT_BUF_SIZE		127
+
+static ssize_t
+ftrace_event_write(struct file *file, const char __user *ubuf,
+		   size_t cnt, loff_t *ppos)
+{
+	struct trace_parser parser;
+	struct seq_file *m = file->private_data;
+	struct trace_array *tr = m->private;
+	ssize_t read, ret;
+
+	if (!cnt)
+		return 0;
+
+	ret = tracing_update_buffers();
+	if (ret < 0)
+		return ret;
+
+	if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
+		return -ENOMEM;
+
+	read = trace_get_user(&parser, ubuf, cnt, ppos);
+
+	if (read >= 0 && trace_parser_loaded((&parser))) {
+		int set = 1;
+
+		if (*parser.buffer == '!')
+			set = 0;
+
+		ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
+		if (ret)
+			goto out_put;
+	}
+
+	ret = read;
+
+ out_put:
+	trace_parser_put(&parser);
+
+	return ret;
+}
+
+static void *
+t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct trace_event_file *file = v;
+	struct trace_event_call *call;
+	struct trace_array *tr = m->private;
+
+	(*pos)++;
+
+	list_for_each_entry_continue(file, &tr->events, list) {
+		call = file->event_call;
+		/*
+		 * The ftrace subsystem is for showing formats only.
+		 * They can not be enabled or disabled via the event files.
+		 */
+		if (call->class && call->class->reg &&
+		    !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
+			return file;
+	}
+
+	return NULL;
+}
+
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+	struct trace_event_file *file;
+	struct trace_array *tr = m->private;
+	loff_t l;
+
+	mutex_lock(&event_mutex);
+
+	file = list_entry(&tr->events, struct trace_event_file, list);
+	for (l = 0; l <= *pos; ) {
+		file = t_next(m, file, &l);
+		if (!file)
+			break;
+	}
+	return file;
+}
+
+static void *
+s_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct trace_event_file *file = v;
+	struct trace_array *tr = m->private;
+
+	(*pos)++;
+
+	list_for_each_entry_continue(file, &tr->events, list) {
+		if (file->flags & EVENT_FILE_FL_ENABLED)
+			return file;
+	}
+
+	return NULL;
+}
+
+static void *s_start(struct seq_file *m, loff_t *pos)
+{
+	struct trace_event_file *file;
+	struct trace_array *tr = m->private;
+	loff_t l;
+
+	mutex_lock(&event_mutex);
+
+	file = list_entry(&tr->events, struct trace_event_file, list);
+	for (l = 0; l <= *pos; ) {
+		file = s_next(m, file, &l);
+		if (!file)
+			break;
+	}
+	return file;
+}
+
+static int t_show(struct seq_file *m, void *v)
+{
+	struct trace_event_file *file = v;
+	struct trace_event_call *call = file->event_call;
+
+	if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
+		seq_printf(m, "%s:", call->class->system);
+	seq_printf(m, "%s\n", trace_event_name(call));
+
+	return 0;
+}
+
+static void t_stop(struct seq_file *m, void *p)
+{
+	mutex_unlock(&event_mutex);
+}
+
+static void *
+__next(struct seq_file *m, void *v, loff_t *pos, int type)
+{
+	struct trace_array *tr = m->private;
+	struct trace_pid_list *pid_list;
+
+	if (type == TRACE_PIDS)
+		pid_list = rcu_dereference_sched(tr->filtered_pids);
+	else
+		pid_list = rcu_dereference_sched(tr->filtered_no_pids);
+
+	return trace_pid_next(pid_list, v, pos);
+}
+
+static void *
+p_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return __next(m, v, pos, TRACE_PIDS);
+}
+
+static void *
+np_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return __next(m, v, pos, TRACE_NO_PIDS);
+}
+
+static void *__start(struct seq_file *m, loff_t *pos, int type)
+	__acquires(RCU)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_array *tr = m->private;
+
+	/*
+	 * Grab the mutex, to keep calls to p_next() having the same
+	 * tr->filtered_pids as p_start() has.
+	 * If we just passed the tr->filtered_pids around, then RCU would
+	 * have been enough, but doing that makes things more complex.
+	 */
+	mutex_lock(&event_mutex);
+	rcu_read_lock_sched();
+
+	if (type == TRACE_PIDS)
+		pid_list = rcu_dereference_sched(tr->filtered_pids);
+	else
+		pid_list = rcu_dereference_sched(tr->filtered_no_pids);
+
+	if (!pid_list)
+		return NULL;
+
+	return trace_pid_start(pid_list, pos);
+}
+
+static void *p_start(struct seq_file *m, loff_t *pos)
+	__acquires(RCU)
+{
+	return __start(m, pos, TRACE_PIDS);
+}
+
+static void *np_start(struct seq_file *m, loff_t *pos)
+	__acquires(RCU)
+{
+	return __start(m, pos, TRACE_NO_PIDS);
+}
+
+static void p_stop(struct seq_file *m, void *p)
+	__releases(RCU)
+{
+	rcu_read_unlock_sched();
+	mutex_unlock(&event_mutex);
+}
+
+static ssize_t
+event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
+		  loff_t *ppos)
+{
+	struct trace_event_file *file;
+	unsigned long flags;
+	char buf[4] = "0";
+
+	mutex_lock(&event_mutex);
+	file = event_file_data(filp);
+	if (likely(file))
+		flags = file->flags;
+	mutex_unlock(&event_mutex);
+
+	if (!file || flags & EVENT_FILE_FL_FREED)
+		return -ENODEV;
+
+	if (flags & EVENT_FILE_FL_ENABLED &&
+	    !(flags & EVENT_FILE_FL_SOFT_DISABLED))
+		strcpy(buf, "1");
+
+	if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
+	    flags & EVENT_FILE_FL_SOFT_MODE)
+		strcat(buf, "*");
+
+	strcat(buf, "\n");
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
+}
+
+static ssize_t
+event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
+		   loff_t *ppos)
+{
+	struct trace_event_file *file;
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	ret = tracing_update_buffers();
+	if (ret < 0)
+		return ret;
+
+	switch (val) {
+	case 0:
+	case 1:
+		ret = -ENODEV;
+		mutex_lock(&event_mutex);
+		file = event_file_data(filp);
+		if (likely(file && !(file->flags & EVENT_FILE_FL_FREED)))
+			ret = ftrace_event_enable_disable(file, val);
+		mutex_unlock(&event_mutex);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	*ppos += cnt;
+
+	return ret ? ret : cnt;
+}
+
+static ssize_t
+system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
+		   loff_t *ppos)
+{
+	const char set_to_char[4] = { '?', '0', '1', 'X' };
+	struct trace_subsystem_dir *dir = filp->private_data;
+	struct event_subsystem *system = dir->subsystem;
+	struct trace_event_call *call;
+	struct trace_event_file *file;
+	struct trace_array *tr = dir->tr;
+	char buf[2];
+	int set = 0;
+	int ret;
+
+	mutex_lock(&event_mutex);
+	list_for_each_entry(file, &tr->events, list) {
+		call = file->event_call;
+		if ((call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
+		    !trace_event_name(call) || !call->class || !call->class->reg)
+			continue;
+
+		if (system && strcmp(call->class->system, system->name) != 0)
+			continue;
+
+		/*
+		 * We need to find out if all the events are set
+		 * or if all events or cleared, or if we have
+		 * a mixture.
+		 */
+		set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
+
+		/*
+		 * If we have a mixture, no need to look further.
+		 */
+		if (set == 3)
+			break;
+	}
+	mutex_unlock(&event_mutex);
+
+	buf[0] = set_to_char[set];
+	buf[1] = '\n';
+
+	ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
+
+	return ret;
+}
+
+static ssize_t
+system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
+		    loff_t *ppos)
+{
+	struct trace_subsystem_dir *dir = filp->private_data;
+	struct event_subsystem *system = dir->subsystem;
+	const char *name = NULL;
+	unsigned long val;
+	ssize_t ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	ret = tracing_update_buffers();
+	if (ret < 0)
+		return ret;
+
+	if (val != 0 && val != 1)
+		return -EINVAL;
+
+	/*
+	 * Opening of "enable" adds a ref count to system,
+	 * so the name is safe to use.
+	 */
+	if (system)
+		name = system->name;
+
+	ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
+	if (ret)
+		goto out;
+
+	ret = cnt;
+
+out:
+	*ppos += cnt;
+
+	return ret;
+}
+
+enum {
+	FORMAT_HEADER		= 1,
+	FORMAT_FIELD_SEPERATOR	= 2,
+	FORMAT_PRINTFMT		= 3,
+};
+
+static void *f_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct trace_event_call *call = event_file_data(m->private);
+	struct list_head *common_head = &ftrace_common_fields;
+	struct list_head *head = trace_get_fields(call);
+	struct list_head *node = v;
+
+	(*pos)++;
+
+	switch ((unsigned long)v) {
+	case FORMAT_HEADER:
+		node = common_head;
+		break;
+
+	case FORMAT_FIELD_SEPERATOR:
+		node = head;
+		break;
+
+	case FORMAT_PRINTFMT:
+		/* all done */
+		return NULL;
+	}
+
+	node = node->prev;
+	if (node == common_head)
+		return (void *)FORMAT_FIELD_SEPERATOR;
+	else if (node == head)
+		return (void *)FORMAT_PRINTFMT;
+	else
+		return node;
+}
+
+static int f_show(struct seq_file *m, void *v)
+{
+	struct trace_event_call *call = event_file_data(m->private);
+	struct ftrace_event_field *field;
+	const char *array_descriptor;
+
+	switch ((unsigned long)v) {
+	case FORMAT_HEADER:
+		seq_printf(m, "name: %s\n", trace_event_name(call));
+		seq_printf(m, "ID: %d\n", call->event.type);
+		seq_puts(m, "format:\n");
+		return 0;
+
+	case FORMAT_FIELD_SEPERATOR:
+		seq_putc(m, '\n');
+		return 0;
+
+	case FORMAT_PRINTFMT:
+		seq_printf(m, "\nprint fmt: %s\n",
+			   call->print_fmt);
+		return 0;
+	}
+
+	field = list_entry(v, struct ftrace_event_field, link);
+	/*
+	 * Smartly shows the array type(except dynamic array).
+	 * Normal:
+	 *	field:TYPE VAR
+	 * If TYPE := TYPE[LEN], it is shown:
+	 *	field:TYPE VAR[LEN]
+	 */
+	array_descriptor = strchr(field->type, '[');
+
+	if (str_has_prefix(field->type, "__data_loc"))
+		array_descriptor = NULL;
+
+	if (!array_descriptor)
+		seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
+			   field->type, field->name, field->offset,
+			   field->size, !!field->is_signed);
+	else if (field->len)
+		seq_printf(m, "\tfield:%.*s %s[%d];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
+			   (int)(array_descriptor - field->type),
+			   field->type, field->name,
+			   field->len, field->offset,
+			   field->size, !!field->is_signed);
+	else
+		seq_printf(m, "\tfield:%.*s %s[];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
+				(int)(array_descriptor - field->type),
+				field->type, field->name,
+				field->offset, field->size, !!field->is_signed);
+
+	return 0;
+}
+
+static void *f_start(struct seq_file *m, loff_t *pos)
+{
+	void *p = (void *)FORMAT_HEADER;
+	loff_t l = 0;
+
+	/* ->stop() is called even if ->start() fails */
+	mutex_lock(&event_mutex);
+	if (!event_file_data(m->private))
+		return ERR_PTR(-ENODEV);
+
+	while (l < *pos && p)
+		p = f_next(m, p, &l);
+
+	return p;
+}
+
+static void f_stop(struct seq_file *m, void *p)
+{
+	mutex_unlock(&event_mutex);
+}
+
+static const struct seq_operations trace_format_seq_ops = {
+	.start		= f_start,
+	.next		= f_next,
+	.stop		= f_stop,
+	.show		= f_show,
+};
+
+static int trace_format_open(struct inode *inode, struct file *file)
+{
+	struct seq_file *m;
+	int ret;
+
+	/* Do we want to hide event format files on tracefs lockdown? */
+
+	ret = seq_open(file, &trace_format_seq_ops);
+	if (ret < 0)
+		return ret;
+
+	m = file->private_data;
+	m->private = file;
+
+	return 0;
+}
+
+static ssize_t
+event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
+{
+	int id = (long)event_file_data(filp);
+	char buf[32];
+	int len;
+
+	if (unlikely(!id))
+		return -ENODEV;
+
+	len = sprintf(buf, "%d\n", id);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
+}
+
+static ssize_t
+event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
+		  loff_t *ppos)
+{
+	struct trace_event_file *file;
+	struct trace_seq *s;
+	int r = -ENODEV;
+
+	if (*ppos)
+		return 0;
+
+	s = kmalloc(sizeof(*s), GFP_KERNEL);
+
+	if (!s)
+		return -ENOMEM;
+
+	trace_seq_init(s);
+
+	mutex_lock(&event_mutex);
+	file = event_file_data(filp);
+	if (file && !(file->flags & EVENT_FILE_FL_FREED))
+		print_event_filter(file, s);
+	mutex_unlock(&event_mutex);
+
+	if (file)
+		r = simple_read_from_buffer(ubuf, cnt, ppos,
+					    s->buffer, trace_seq_used(s));
+
+	kfree(s);
+
+	return r;
+}
+
+static ssize_t
+event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
+		   loff_t *ppos)
+{
+	struct trace_event_file *file;
+	char *buf;
+	int err = -ENODEV;
+
+	if (cnt >= PAGE_SIZE)
+		return -EINVAL;
+
+	buf = memdup_user_nul(ubuf, cnt);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	mutex_lock(&event_mutex);
+	file = event_file_data(filp);
+	if (file)
+		err = apply_event_filter(file, buf);
+	mutex_unlock(&event_mutex);
+
+	kfree(buf);
+	if (err < 0)
+		return err;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static LIST_HEAD(event_subsystems);
+
+static int subsystem_open(struct inode *inode, struct file *filp)
+{
+	struct trace_subsystem_dir *dir = NULL, *iter_dir;
+	struct trace_array *tr = NULL, *iter_tr;
+	struct event_subsystem *system = NULL;
+	int ret;
+
+	if (tracing_is_disabled())
+		return -ENODEV;
+
+	/* Make sure the system still exists */
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+	list_for_each_entry(iter_tr, &ftrace_trace_arrays, list) {
+		list_for_each_entry(iter_dir, &iter_tr->systems, list) {
+			if (iter_dir == inode->i_private) {
+				/* Don't open systems with no events */
+				tr = iter_tr;
+				dir = iter_dir;
+				if (dir->nr_events) {
+					__get_system_dir(dir);
+					system = dir->subsystem;
+				}
+				goto exit_loop;
+			}
+		}
+	}
+ exit_loop:
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+
+	if (!system)
+		return -ENODEV;
+
+	/* Still need to increment the ref count of the system */
+	if (trace_array_get(tr) < 0) {
+		put_system(dir);
+		return -ENODEV;
+	}
+
+	ret = tracing_open_generic(inode, filp);
+	if (ret < 0) {
+		trace_array_put(tr);
+		put_system(dir);
+	}
+
+	return ret;
+}
+
+static int system_tr_open(struct inode *inode, struct file *filp)
+{
+	struct trace_subsystem_dir *dir;
+	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	/* Make a temporary dir that has no system but points to tr */
+	dir = kzalloc(sizeof(*dir), GFP_KERNEL);
+	if (!dir)
+		return -ENOMEM;
+
+	ret = tracing_open_generic_tr(inode, filp);
+	if (ret < 0) {
+		kfree(dir);
+		return ret;
+	}
+	dir->tr = tr;
+	filp->private_data = dir;
+
+	return 0;
+}
+
+static int subsystem_release(struct inode *inode, struct file *file)
+{
+	struct trace_subsystem_dir *dir = file->private_data;
+
+	trace_array_put(dir->tr);
+
+	/*
+	 * If dir->subsystem is NULL, then this is a temporary
+	 * descriptor that was made for a trace_array to enable
+	 * all subsystems.
+	 */
+	if (dir->subsystem)
+		put_system(dir);
+	else
+		kfree(dir);
+
+	return 0;
+}
+
+static ssize_t
+subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
+		      loff_t *ppos)
+{
+	struct trace_subsystem_dir *dir = filp->private_data;
+	struct event_subsystem *system = dir->subsystem;
+	struct trace_seq *s;
+	int r;
+
+	if (*ppos)
+		return 0;
+
+	s = kmalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	trace_seq_init(s);
+
+	print_subsystem_event_filter(system, s);
+	r = simple_read_from_buffer(ubuf, cnt, ppos,
+				    s->buffer, trace_seq_used(s));
+
+	kfree(s);
+
+	return r;
+}
+
+static ssize_t
+subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
+		       loff_t *ppos)
+{
+	struct trace_subsystem_dir *dir = filp->private_data;
+	char *buf;
+	int err;
+
+	if (cnt >= PAGE_SIZE)
+		return -EINVAL;
+
+	buf = memdup_user_nul(ubuf, cnt);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	err = apply_subsystem_event_filter(dir, buf);
+	kfree(buf);
+	if (err < 0)
+		return err;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static ssize_t
+show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
+{
+	int (*func)(struct trace_seq *s) = filp->private_data;
+	struct trace_seq *s;
+	int r;
+
+	if (*ppos)
+		return 0;
+
+	s = kmalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	trace_seq_init(s);
+
+	func(s);
+	r = simple_read_from_buffer(ubuf, cnt, ppos,
+				    s->buffer, trace_seq_used(s));
+
+	kfree(s);
+
+	return r;
+}
+
+static void ignore_task_cpu(void *data)
+{
+	struct trace_array *tr = data;
+	struct trace_pid_list *pid_list;
+	struct trace_pid_list *no_pid_list;
+
+	/*
+	 * This function is called by on_each_cpu() while the
+	 * event_mutex is held.
+	 */
+	pid_list = rcu_dereference_protected(tr->filtered_pids,
+					     mutex_is_locked(&event_mutex));
+	no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
+					     mutex_is_locked(&event_mutex));
+
+	this_cpu_write(tr->array_buffer.data->ignore_pid,
+		       trace_ignore_this_task(pid_list, no_pid_list, current));
+}
+
+static void register_pid_events(struct trace_array *tr)
+{
+	/*
+	 * Register a probe that is called before all other probes
+	 * to set ignore_pid if next or prev do not match.
+	 * Register a probe this is called after all other probes
+	 * to only keep ignore_pid set if next pid matches.
+	 */
+	register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
+					 tr, INT_MAX);
+	register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
+					 tr, 0);
+
+	register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
+					 tr, INT_MAX);
+	register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
+					 tr, 0);
+
+	register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
+					     tr, INT_MAX);
+	register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
+					     tr, 0);
+
+	register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
+					 tr, INT_MAX);
+	register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
+					 tr, 0);
+}
+
+static ssize_t
+event_pid_write(struct file *filp, const char __user *ubuf,
+		size_t cnt, loff_t *ppos, int type)
+{
+	struct seq_file *m = filp->private_data;
+	struct trace_array *tr = m->private;
+	struct trace_pid_list *filtered_pids = NULL;
+	struct trace_pid_list *other_pids = NULL;
+	struct trace_pid_list *pid_list;
+	struct trace_event_file *file;
+	ssize_t ret;
+
+	if (!cnt)
+		return 0;
+
+	ret = tracing_update_buffers();
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&event_mutex);
+
+	if (type == TRACE_PIDS) {
+		filtered_pids = rcu_dereference_protected(tr->filtered_pids,
+							  lockdep_is_held(&event_mutex));
+		other_pids = rcu_dereference_protected(tr->filtered_no_pids,
+							  lockdep_is_held(&event_mutex));
+	} else {
+		filtered_pids = rcu_dereference_protected(tr->filtered_no_pids,
+							  lockdep_is_held(&event_mutex));
+		other_pids = rcu_dereference_protected(tr->filtered_pids,
+							  lockdep_is_held(&event_mutex));
+	}
+
+	ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
+	if (ret < 0)
+		goto out;
+
+	if (type == TRACE_PIDS)
+		rcu_assign_pointer(tr->filtered_pids, pid_list);
+	else
+		rcu_assign_pointer(tr->filtered_no_pids, pid_list);
+
+	list_for_each_entry(file, &tr->events, list) {
+		set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
+	}
+
+	if (filtered_pids) {
+		tracepoint_synchronize_unregister();
+		trace_pid_list_free(filtered_pids);
+	} else if (pid_list && !other_pids) {
+		register_pid_events(tr);
+	}
+
+	/*
+	 * Ignoring of pids is done at task switch. But we have to
+	 * check for those tasks that are currently running.
+	 * Always do this in case a pid was appended or removed.
+	 */
+	on_each_cpu(ignore_task_cpu, tr, 1);
+
+ out:
+	mutex_unlock(&event_mutex);
+
+	if (ret > 0)
+		*ppos += ret;
+
+	return ret;
+}
+
+static ssize_t
+ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
+		       size_t cnt, loff_t *ppos)
+{
+	return event_pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
+}
+
+static ssize_t
+ftrace_event_npid_write(struct file *filp, const char __user *ubuf,
+			size_t cnt, loff_t *ppos)
+{
+	return event_pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
+}
+
+static int ftrace_event_avail_open(struct inode *inode, struct file *file);
+static int ftrace_event_set_open(struct inode *inode, struct file *file);
+static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
+static int ftrace_event_set_npid_open(struct inode *inode, struct file *file);
+static int ftrace_event_release(struct inode *inode, struct file *file);
+
+static const struct seq_operations show_event_seq_ops = {
+	.start = t_start,
+	.next = t_next,
+	.show = t_show,
+	.stop = t_stop,
+};
+
+static const struct seq_operations show_set_event_seq_ops = {
+	.start = s_start,
+	.next = s_next,
+	.show = t_show,
+	.stop = t_stop,
+};
+
+static const struct seq_operations show_set_pid_seq_ops = {
+	.start = p_start,
+	.next = p_next,
+	.show = trace_pid_show,
+	.stop = p_stop,
+};
+
+static const struct seq_operations show_set_no_pid_seq_ops = {
+	.start = np_start,
+	.next = np_next,
+	.show = trace_pid_show,
+	.stop = p_stop,
+};
+
+static const struct file_operations ftrace_avail_fops = {
+	.open = ftrace_event_avail_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+static const struct file_operations ftrace_set_event_fops = {
+	.open = ftrace_event_set_open,
+	.read = seq_read,
+	.write = ftrace_event_write,
+	.llseek = seq_lseek,
+	.release = ftrace_event_release,
+};
+
+static const struct file_operations ftrace_set_event_pid_fops = {
+	.open = ftrace_event_set_pid_open,
+	.read = seq_read,
+	.write = ftrace_event_pid_write,
+	.llseek = seq_lseek,
+	.release = ftrace_event_release,
+};
+
+static const struct file_operations ftrace_set_event_notrace_pid_fops = {
+	.open = ftrace_event_set_npid_open,
+	.read = seq_read,
+	.write = ftrace_event_npid_write,
+	.llseek = seq_lseek,
+	.release = ftrace_event_release,
+};
+
+static const struct file_operations ftrace_enable_fops = {
+	.open = tracing_open_file_tr,
+	.read = event_enable_read,
+	.write = event_enable_write,
+	.release = tracing_release_file_tr,
+	.llseek = default_llseek,
+};
+
+static const struct file_operations ftrace_event_format_fops = {
+	.open = trace_format_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+static const struct file_operations ftrace_event_id_fops = {
+	.read = event_id_read,
+	.llseek = default_llseek,
+};
+
+static const struct file_operations ftrace_event_filter_fops = {
+	.open = tracing_open_file_tr,
+	.read = event_filter_read,
+	.write = event_filter_write,
+	.release = tracing_release_file_tr,
+	.llseek = default_llseek,
+};
+
+static const struct file_operations ftrace_subsystem_filter_fops = {
+	.open = subsystem_open,
+	.read = subsystem_filter_read,
+	.write = subsystem_filter_write,
+	.llseek = default_llseek,
+	.release = subsystem_release,
+};
+
+static const struct file_operations ftrace_system_enable_fops = {
+	.open = subsystem_open,
+	.read = system_enable_read,
+	.write = system_enable_write,
+	.llseek = default_llseek,
+	.release = subsystem_release,
+};
+
+static const struct file_operations ftrace_tr_enable_fops = {
+	.open = system_tr_open,
+	.read = system_enable_read,
+	.write = system_enable_write,
+	.llseek = default_llseek,
+	.release = subsystem_release,
+};
+
+static const struct file_operations ftrace_show_header_fops = {
+	.open = tracing_open_generic,
+	.read = show_header,
+	.llseek = default_llseek,
+};
+
+static int
+ftrace_event_open(struct inode *inode, struct file *file,
+		  const struct seq_operations *seq_ops)
+{
+	struct seq_file *m;
+	int ret;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	ret = seq_open(file, seq_ops);
+	if (ret < 0)
+		return ret;
+	m = file->private_data;
+	/* copy tr over to seq ops */
+	m->private = inode->i_private;
+
+	return ret;
+}
+
+static int ftrace_event_release(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+
+	trace_array_put(tr);
+
+	return seq_release(inode, file);
+}
+
+static int
+ftrace_event_avail_open(struct inode *inode, struct file *file)
+{
+	const struct seq_operations *seq_ops = &show_event_seq_ops;
+
+	/* Checks for tracefs lockdown */
+	return ftrace_event_open(inode, file, seq_ops);
+}
+
+static int
+ftrace_event_set_open(struct inode *inode, struct file *file)
+{
+	const struct seq_operations *seq_ops = &show_set_event_seq_ops;
+	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	if ((file->f_mode & FMODE_WRITE) &&
+	    (file->f_flags & O_TRUNC))
+		ftrace_clear_events(tr);
+
+	ret = ftrace_event_open(inode, file, seq_ops);
+	if (ret < 0)
+		trace_array_put(tr);
+	return ret;
+}
+
+static int
+ftrace_event_set_pid_open(struct inode *inode, struct file *file)
+{
+	const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
+	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	if ((file->f_mode & FMODE_WRITE) &&
+	    (file->f_flags & O_TRUNC))
+		ftrace_clear_event_pids(tr, TRACE_PIDS);
+
+	ret = ftrace_event_open(inode, file, seq_ops);
+	if (ret < 0)
+		trace_array_put(tr);
+	return ret;
+}
+
+static int
+ftrace_event_set_npid_open(struct inode *inode, struct file *file)
+{
+	const struct seq_operations *seq_ops = &show_set_no_pid_seq_ops;
+	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	if ((file->f_mode & FMODE_WRITE) &&
+	    (file->f_flags & O_TRUNC))
+		ftrace_clear_event_pids(tr, TRACE_NO_PIDS);
+
+	ret = ftrace_event_open(inode, file, seq_ops);
+	if (ret < 0)
+		trace_array_put(tr);
+	return ret;
+}
+
+static struct event_subsystem *
+create_new_subsystem(const char *name)
+{
+	struct event_subsystem *system;
+
+	/* need to create new entry */
+	system = kmalloc(sizeof(*system), GFP_KERNEL);
+	if (!system)
+		return NULL;
+
+	system->ref_count = 1;
+
+	/* Only allocate if dynamic (kprobes and modules) */
+	system->name = kstrdup_const(name, GFP_KERNEL);
+	if (!system->name)
+		goto out_free;
+
+	system->filter = NULL;
+
+	system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
+	if (!system->filter)
+		goto out_free;
+
+	list_add(&system->list, &event_subsystems);
+
+	return system;
+
+ out_free:
+	kfree_const(system->name);
+	kfree(system);
+	return NULL;
+}
+
+static struct dentry *
+event_subsystem_dir(struct trace_array *tr, const char *name,
+		    struct trace_event_file *file, struct dentry *parent)
+{
+	struct event_subsystem *system, *iter;
+	struct trace_subsystem_dir *dir;
+	struct dentry *entry;
+
+	/* First see if we did not already create this dir */
+	list_for_each_entry(dir, &tr->systems, list) {
+		system = dir->subsystem;
+		if (strcmp(system->name, name) == 0) {
+			dir->nr_events++;
+			file->system = dir;
+			return dir->entry;
+		}
+	}
+
+	/* Now see if the system itself exists. */
+	system = NULL;
+	list_for_each_entry(iter, &event_subsystems, list) {
+		if (strcmp(iter->name, name) == 0) {
+			system = iter;
+			break;
+		}
+	}
+
+	dir = kmalloc(sizeof(*dir), GFP_KERNEL);
+	if (!dir)
+		goto out_fail;
+
+	if (!system) {
+		system = create_new_subsystem(name);
+		if (!system)
+			goto out_free;
+	} else
+		__get_system(system);
+
+	dir->entry = tracefs_create_dir(name, parent);
+	if (!dir->entry) {
+		pr_warn("Failed to create system directory %s\n", name);
+		__put_system(system);
+		goto out_free;
+	}
+
+	dir->tr = tr;
+	dir->ref_count = 1;
+	dir->nr_events = 1;
+	dir->subsystem = system;
+	file->system = dir;
+
+	/* the ftrace system is special, do not create enable or filter files */
+	if (strcmp(name, "ftrace") != 0) {
+
+		entry = tracefs_create_file("filter", TRACE_MODE_WRITE,
+					    dir->entry, dir,
+					    &ftrace_subsystem_filter_fops);
+		if (!entry) {
+			kfree(system->filter);
+			system->filter = NULL;
+			pr_warn("Could not create tracefs '%s/filter' entry\n", name);
+		}
+
+		trace_create_file("enable", TRACE_MODE_WRITE, dir->entry, dir,
+				  &ftrace_system_enable_fops);
+	}
+
+	list_add(&dir->list, &tr->systems);
+
+	return dir->entry;
+
+ out_free:
+	kfree(dir);
+ out_fail:
+	/* Only print this message if failed on memory allocation */
+	if (!dir || !system)
+		pr_warn("No memory to create event subsystem %s\n", name);
+	return NULL;
+}
+
+static int
+event_define_fields(struct trace_event_call *call)
+{
+	struct list_head *head;
+	int ret = 0;
+
+	/*
+	 * Other events may have the same class. Only update
+	 * the fields if they are not already defined.
+	 */
+	head = trace_get_fields(call);
+	if (list_empty(head)) {
+		struct trace_event_fields *field = call->class->fields_array;
+		unsigned int offset = sizeof(struct trace_entry);
+
+		for (; field->type; field++) {
+			if (field->type == TRACE_FUNCTION_TYPE) {
+				field->define_fields(call);
+				break;
+			}
+
+			offset = ALIGN(offset, field->align);
+			ret = trace_define_field_ext(call, field->type, field->name,
+						 offset, field->size,
+						 field->is_signed, field->filter_type,
+						 field->len);
+			if (WARN_ON_ONCE(ret)) {
+				pr_err("error code is %d\n", ret);
+				break;
+			}
+
+			offset += field->size;
+		}
+	}
+
+	return ret;
+}
+
+static int
+event_create_dir(struct dentry *parent, struct trace_event_file *file)
+{
+	struct trace_event_call *call = file->event_call;
+	struct trace_array *tr = file->tr;
+	struct dentry *d_events;
+	const char *name;
+	int ret;
+
+	/*
+	 * If the trace point header did not define TRACE_SYSTEM
+	 * then the system would be called "TRACE_SYSTEM".
+	 */
+	if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
+		d_events = event_subsystem_dir(tr, call->class->system, file, parent);
+		if (!d_events)
+			return -ENOMEM;
+	} else
+		d_events = parent;
+
+	name = trace_event_name(call);
+	file->dir = tracefs_create_dir(name, d_events);
+	if (!file->dir) {
+		pr_warn("Could not create tracefs '%s' directory\n", name);
+		return -1;
+	}
+
+	if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
+		trace_create_file("enable", TRACE_MODE_WRITE, file->dir, file,
+				  &ftrace_enable_fops);
+
+#ifdef CONFIG_PERF_EVENTS
+	if (call->event.type && call->class->reg)
+		trace_create_file("id", TRACE_MODE_READ, file->dir,
+				  (void *)(long)call->event.type,
+				  &ftrace_event_id_fops);
+#endif
+
+	ret = event_define_fields(call);
+	if (ret < 0) {
+		pr_warn("Could not initialize trace point events/%s\n", name);
+		return ret;
+	}
+
+	/*
+	 * Only event directories that can be enabled should have
+	 * triggers or filters.
+	 */
+	if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
+		trace_create_file("filter", TRACE_MODE_WRITE, file->dir,
+				  file, &ftrace_event_filter_fops);
+
+		trace_create_file("trigger", TRACE_MODE_WRITE, file->dir,
+				  file, &event_trigger_fops);
+	}
+
+#ifdef CONFIG_HIST_TRIGGERS
+	trace_create_file("hist", TRACE_MODE_READ, file->dir, file,
+			  &event_hist_fops);
+#endif
+#ifdef CONFIG_HIST_TRIGGERS_DEBUG
+	trace_create_file("hist_debug", TRACE_MODE_READ, file->dir, file,
+			  &event_hist_debug_fops);
+#endif
+	trace_create_file("format", TRACE_MODE_READ, file->dir, call,
+			  &ftrace_event_format_fops);
+
+#ifdef CONFIG_TRACE_EVENT_INJECT
+	if (call->event.type && call->class->reg)
+		trace_create_file("inject", 0200, file->dir, file,
+				  &event_inject_fops);
+#endif
+
+	return 0;
+}
+
+static void remove_event_from_tracers(struct trace_event_call *call)
+{
+	struct trace_event_file *file;
+	struct trace_array *tr;
+
+	do_for_each_event_file_safe(tr, file) {
+		if (file->event_call != call)
+			continue;
+
+		remove_event_file_dir(file);
+		/*
+		 * The do_for_each_event_file_safe() is
+		 * a double loop. After finding the call for this
+		 * trace_array, we use break to jump to the next
+		 * trace_array.
+		 */
+		break;
+	} while_for_each_event_file();
+}
+
+static void event_remove(struct trace_event_call *call)
+{
+	struct trace_array *tr;
+	struct trace_event_file *file;
+
+	do_for_each_event_file(tr, file) {
+		if (file->event_call != call)
+			continue;
+
+		if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
+			tr->clear_trace = true;
+
+		ftrace_event_enable_disable(file, 0);
+		/*
+		 * The do_for_each_event_file() is
+		 * a double loop. After finding the call for this
+		 * trace_array, we use break to jump to the next
+		 * trace_array.
+		 */
+		break;
+	} while_for_each_event_file();
+
+	if (call->event.funcs)
+		__unregister_trace_event(&call->event);
+	remove_event_from_tracers(call);
+	list_del(&call->list);
+}
+
+static int event_init(struct trace_event_call *call)
+{
+	int ret = 0;
+	const char *name;
+
+	name = trace_event_name(call);
+	if (WARN_ON(!name))
+		return -EINVAL;
+
+	if (call->class->raw_init) {
+		ret = call->class->raw_init(call);
+		if (ret < 0 && ret != -ENOSYS)
+			pr_warn("Could not initialize trace events/%s\n", name);
+	}
+
+	return ret;
+}
+
+static int
+__register_event(struct trace_event_call *call, struct module *mod)
+{
+	int ret;
+
+	ret = event_init(call);
+	if (ret < 0)
+		return ret;
+
+	list_add(&call->list, &ftrace_events);
+	if (call->flags & TRACE_EVENT_FL_DYNAMIC)
+		atomic_set(&call->refcnt, 0);
+	else
+		call->module = mod;
+
+	return 0;
+}
+
+static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
+{
+	int rlen;
+	int elen;
+
+	/* Find the length of the eval value as a string */
+	elen = snprintf(ptr, 0, "%ld", map->eval_value);
+	/* Make sure there's enough room to replace the string with the value */
+	if (len < elen)
+		return NULL;
+
+	snprintf(ptr, elen + 1, "%ld", map->eval_value);
+
+	/* Get the rest of the string of ptr */
+	rlen = strlen(ptr + len);
+	memmove(ptr + elen, ptr + len, rlen);
+	/* Make sure we end the new string */
+	ptr[elen + rlen] = 0;
+
+	return ptr + elen;
+}
+
+static void update_event_printk(struct trace_event_call *call,
+				struct trace_eval_map *map)
+{
+	char *ptr;
+	int quote = 0;
+	int len = strlen(map->eval_string);
+
+	for (ptr = call->print_fmt; *ptr; ptr++) {
+		if (*ptr == '\\') {
+			ptr++;
+			/* paranoid */
+			if (!*ptr)
+				break;
+			continue;
+		}
+		if (*ptr == '"') {
+			quote ^= 1;
+			continue;
+		}
+		if (quote)
+			continue;
+		if (isdigit(*ptr)) {
+			/* skip numbers */
+			do {
+				ptr++;
+				/* Check for alpha chars like ULL */
+			} while (isalnum(*ptr));
+			if (!*ptr)
+				break;
+			/*
+			 * A number must have some kind of delimiter after
+			 * it, and we can ignore that too.
+			 */
+			continue;
+		}
+		if (isalpha(*ptr) || *ptr == '_') {
+			if (strncmp(map->eval_string, ptr, len) == 0 &&
+			    !isalnum(ptr[len]) && ptr[len] != '_') {
+				ptr = eval_replace(ptr, map, len);
+				/* enum/sizeof string smaller than value */
+				if (WARN_ON_ONCE(!ptr))
+					return;
+				/*
+				 * No need to decrement here, as eval_replace()
+				 * returns the pointer to the character passed
+				 * the eval, and two evals can not be placed
+				 * back to back without something in between.
+				 * We can skip that something in between.
+				 */
+				continue;
+			}
+		skip_more:
+			do {
+				ptr++;
+			} while (isalnum(*ptr) || *ptr == '_');
+			if (!*ptr)
+				break;
+			/*
+			 * If what comes after this variable is a '.' or
+			 * '->' then we can continue to ignore that string.
+			 */
+			if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
+				ptr += *ptr == '.' ? 1 : 2;
+				if (!*ptr)
+					break;
+				goto skip_more;
+			}
+			/*
+			 * Once again, we can skip the delimiter that came
+			 * after the string.
+			 */
+			continue;
+		}
+	}
+}
+
+static void add_str_to_module(struct module *module, char *str)
+{
+	struct module_string *modstr;
+
+	modstr = kmalloc(sizeof(*modstr), GFP_KERNEL);
+
+	/*
+	 * If we failed to allocate memory here, then we'll just
+	 * let the str memory leak when the module is removed.
+	 * If this fails to allocate, there's worse problems than
+	 * a leaked string on module removal.
+	 */
+	if (WARN_ON_ONCE(!modstr))
+		return;
+
+	modstr->module = module;
+	modstr->str = str;
+
+	list_add(&modstr->next, &module_strings);
+}
+
+static void update_event_fields(struct trace_event_call *call,
+				struct trace_eval_map *map)
+{
+	struct ftrace_event_field *field;
+	struct list_head *head;
+	char *ptr;
+	char *str;
+	int len = strlen(map->eval_string);
+
+	/* Dynamic events should never have field maps */
+	if (WARN_ON_ONCE(call->flags & TRACE_EVENT_FL_DYNAMIC))
+		return;
+
+	head = trace_get_fields(call);
+	list_for_each_entry(field, head, link) {
+		ptr = strchr(field->type, '[');
+		if (!ptr)
+			continue;
+		ptr++;
+
+		if (!isalpha(*ptr) && *ptr != '_')
+			continue;
+
+		if (strncmp(map->eval_string, ptr, len) != 0)
+			continue;
+
+		str = kstrdup(field->type, GFP_KERNEL);
+		if (WARN_ON_ONCE(!str))
+			return;
+		ptr = str + (ptr - field->type);
+		ptr = eval_replace(ptr, map, len);
+		/* enum/sizeof string smaller than value */
+		if (WARN_ON_ONCE(!ptr)) {
+			kfree(str);
+			continue;
+		}
+
+		/*
+		 * If the event is part of a module, then we need to free the string
+		 * when the module is removed. Otherwise, it will stay allocated
+		 * until a reboot.
+		 */
+		if (call->module)
+			add_str_to_module(call->module, str);
+
+		field->type = str;
+	}
+}
+
+void trace_event_eval_update(struct trace_eval_map **map, int len)
+{
+	struct trace_event_call *call, *p;
+	const char *last_system = NULL;
+	bool first = false;
+	int last_i;
+	int i;
+
+	down_write(&trace_event_sem);
+	list_for_each_entry_safe(call, p, &ftrace_events, list) {
+		/* events are usually grouped together with systems */
+		if (!last_system || call->class->system != last_system) {
+			first = true;
+			last_i = 0;
+			last_system = call->class->system;
+		}
+
+		/*
+		 * Since calls are grouped by systems, the likelihood that the
+		 * next call in the iteration belongs to the same system as the
+		 * previous call is high. As an optimization, we skip searching
+		 * for a map[] that matches the call's system if the last call
+		 * was from the same system. That's what last_i is for. If the
+		 * call has the same system as the previous call, then last_i
+		 * will be the index of the first map[] that has a matching
+		 * system.
+		 */
+		for (i = last_i; i < len; i++) {
+			if (call->class->system == map[i]->system) {
+				/* Save the first system if need be */
+				if (first) {
+					last_i = i;
+					first = false;
+				}
+				update_event_printk(call, map[i]);
+				update_event_fields(call, map[i]);
+			}
+		}
+		cond_resched();
+	}
+	up_write(&trace_event_sem);
+}
+
+static struct trace_event_file *
+trace_create_new_event(struct trace_event_call *call,
+		       struct trace_array *tr)
+{
+	struct trace_pid_list *no_pid_list;
+	struct trace_pid_list *pid_list;
+	struct trace_event_file *file;
+	unsigned int first;
+
+	file = kmem_cache_alloc(file_cachep, GFP_TRACE);
+	if (!file)
+		return NULL;
+
+	pid_list = rcu_dereference_protected(tr->filtered_pids,
+					     lockdep_is_held(&event_mutex));
+	no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
+					     lockdep_is_held(&event_mutex));
+
+	if (!trace_pid_list_first(pid_list, &first) ||
+	    !trace_pid_list_first(no_pid_list, &first))
+		file->flags |= EVENT_FILE_FL_PID_FILTER;
+
+	file->event_call = call;
+	file->tr = tr;
+	atomic_set(&file->sm_ref, 0);
+	atomic_set(&file->tm_ref, 0);
+	INIT_LIST_HEAD(&file->triggers);
+	list_add(&file->list, &tr->events);
+	event_file_get(file);
+
+	return file;
+}
+
+/* Add an event to a trace directory */
+static int
+__trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
+{
+	struct trace_event_file *file;
+
+	file = trace_create_new_event(call, tr);
+	if (!file)
+		return -ENOMEM;
+
+	if (eventdir_initialized)
+		return event_create_dir(tr->event_dir, file);
+	else
+		return event_define_fields(call);
+}
+
+/*
+ * Just create a descriptor for early init. A descriptor is required
+ * for enabling events at boot. We want to enable events before
+ * the filesystem is initialized.
+ */
+static int
+__trace_early_add_new_event(struct trace_event_call *call,
+			    struct trace_array *tr)
+{
+	struct trace_event_file *file;
+
+	file = trace_create_new_event(call, tr);
+	if (!file)
+		return -ENOMEM;
+
+	return event_define_fields(call);
+}
+
+struct ftrace_module_file_ops;
+static void __add_event_to_tracers(struct trace_event_call *call);
+
+/* Add an additional event_call dynamically */
+int trace_add_event_call(struct trace_event_call *call)
+{
+	int ret;
+	lockdep_assert_held(&event_mutex);
+
+	mutex_lock(&trace_types_lock);
+
+	ret = __register_event(call, NULL);
+	if (ret >= 0)
+		__add_event_to_tracers(call);
+
+	mutex_unlock(&trace_types_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(trace_add_event_call);
+
+/*
+ * Must be called under locking of trace_types_lock, event_mutex and
+ * trace_event_sem.
+ */
+static void __trace_remove_event_call(struct trace_event_call *call)
+{
+	event_remove(call);
+	trace_destroy_fields(call);
+	free_event_filter(call->filter);
+	call->filter = NULL;
+}
+
+static int probe_remove_event_call(struct trace_event_call *call)
+{
+	struct trace_array *tr;
+	struct trace_event_file *file;
+
+#ifdef CONFIG_PERF_EVENTS
+	if (call->perf_refcount)
+		return -EBUSY;
+#endif
+	do_for_each_event_file(tr, file) {
+		if (file->event_call != call)
+			continue;
+		/*
+		 * We can't rely on ftrace_event_enable_disable(enable => 0)
+		 * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
+		 * TRACE_REG_UNREGISTER.
+		 */
+		if (file->flags & EVENT_FILE_FL_ENABLED)
+			goto busy;
+
+		if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
+			tr->clear_trace = true;
+		/*
+		 * The do_for_each_event_file_safe() is
+		 * a double loop. After finding the call for this
+		 * trace_array, we use break to jump to the next
+		 * trace_array.
+		 */
+		break;
+	} while_for_each_event_file();
+
+	__trace_remove_event_call(call);
+
+	return 0;
+ busy:
+	/* No need to clear the trace now */
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		tr->clear_trace = false;
+	}
+	return -EBUSY;
+}
+
+/* Remove an event_call */
+int trace_remove_event_call(struct trace_event_call *call)
+{
+	int ret;
+
+	lockdep_assert_held(&event_mutex);
+
+	mutex_lock(&trace_types_lock);
+	down_write(&trace_event_sem);
+	ret = probe_remove_event_call(call);
+	up_write(&trace_event_sem);
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(trace_remove_event_call);
+
+#define for_each_event(event, start, end)			\
+	for (event = start;					\
+	     (unsigned long)event < (unsigned long)end;		\
+	     event++)
+
+#ifdef CONFIG_MODULES
+
+static void trace_module_add_events(struct module *mod)
+{
+	struct trace_event_call **call, **start, **end;
+
+	if (!mod->num_trace_events)
+		return;
+
+	/* Don't add infrastructure for mods without tracepoints */
+	if (trace_module_has_bad_taint(mod)) {
+		pr_err("%s: module has bad taint, not creating trace events\n",
+		       mod->name);
+		return;
+	}
+
+	start = mod->trace_events;
+	end = mod->trace_events + mod->num_trace_events;
+
+	for_each_event(call, start, end) {
+		__register_event(*call, mod);
+		__add_event_to_tracers(*call);
+	}
+}
+
+static void trace_module_remove_events(struct module *mod)
+{
+	struct trace_event_call *call, *p;
+	struct module_string *modstr, *m;
+
+	down_write(&trace_event_sem);
+	list_for_each_entry_safe(call, p, &ftrace_events, list) {
+		if ((call->flags & TRACE_EVENT_FL_DYNAMIC) || !call->module)
+			continue;
+		if (call->module == mod)
+			__trace_remove_event_call(call);
+	}
+	/* Check for any strings allocade for this module */
+	list_for_each_entry_safe(modstr, m, &module_strings, next) {
+		if (modstr->module != mod)
+			continue;
+		list_del(&modstr->next);
+		kfree(modstr->str);
+		kfree(modstr);
+	}
+	up_write(&trace_event_sem);
+
+	/*
+	 * It is safest to reset the ring buffer if the module being unloaded
+	 * registered any events that were used. The only worry is if
+	 * a new module gets loaded, and takes on the same id as the events
+	 * of this module. When printing out the buffer, traced events left
+	 * over from this module may be passed to the new module events and
+	 * unexpected results may occur.
+	 */
+	tracing_reset_all_online_cpus_unlocked();
+}
+
+static int trace_module_notify(struct notifier_block *self,
+			       unsigned long val, void *data)
+{
+	struct module *mod = data;
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+	switch (val) {
+	case MODULE_STATE_COMING:
+		trace_module_add_events(mod);
+		break;
+	case MODULE_STATE_GOING:
+		trace_module_remove_events(mod);
+		break;
+	}
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block trace_module_nb = {
+	.notifier_call = trace_module_notify,
+	.priority = 1, /* higher than trace.c module notify */
+};
+#endif /* CONFIG_MODULES */
+
+/* Create a new event directory structure for a trace directory. */
+static void
+__trace_add_event_dirs(struct trace_array *tr)
+{
+	struct trace_event_call *call;
+	int ret;
+
+	list_for_each_entry(call, &ftrace_events, list) {
+		ret = __trace_add_new_event(call, tr);
+		if (ret < 0)
+			pr_warn("Could not create directory for event %s\n",
+				trace_event_name(call));
+	}
+}
+
+/* Returns any file that matches the system and event */
+struct trace_event_file *
+__find_event_file(struct trace_array *tr, const char *system, const char *event)
+{
+	struct trace_event_file *file;
+	struct trace_event_call *call;
+	const char *name;
+
+	list_for_each_entry(file, &tr->events, list) {
+
+		call = file->event_call;
+		name = trace_event_name(call);
+
+		if (!name || !call->class)
+			continue;
+
+		if (strcmp(event, name) == 0 &&
+		    strcmp(system, call->class->system) == 0)
+			return file;
+	}
+	return NULL;
+}
+
+/* Returns valid trace event files that match system and event */
+struct trace_event_file *
+find_event_file(struct trace_array *tr, const char *system, const char *event)
+{
+	struct trace_event_file *file;
+
+	file = __find_event_file(tr, system, event);
+	if (!file || !file->event_call->class->reg ||
+	    file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
+		return NULL;
+
+	return file;
+}
+
+/**
+ * trace_get_event_file - Find and return a trace event file
+ * @instance: The name of the trace instance containing the event
+ * @system: The name of the system containing the event
+ * @event: The name of the event
+ *
+ * Return a trace event file given the trace instance name, trace
+ * system, and trace event name.  If the instance name is NULL, it
+ * refers to the top-level trace array.
+ *
+ * This function will look it up and return it if found, after calling
+ * trace_array_get() to prevent the instance from going away, and
+ * increment the event's module refcount to prevent it from being
+ * removed.
+ *
+ * To release the file, call trace_put_event_file(), which will call
+ * trace_array_put() and decrement the event's module refcount.
+ *
+ * Return: The trace event on success, ERR_PTR otherwise.
+ */
+struct trace_event_file *trace_get_event_file(const char *instance,
+					      const char *system,
+					      const char *event)
+{
+	struct trace_array *tr = top_trace_array();
+	struct trace_event_file *file = NULL;
+	int ret = -EINVAL;
+
+	if (instance) {
+		tr = trace_array_find_get(instance);
+		if (!tr)
+			return ERR_PTR(-ENOENT);
+	} else {
+		ret = trace_array_get(tr);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
+	mutex_lock(&event_mutex);
+
+	file = find_event_file(tr, system, event);
+	if (!file) {
+		trace_array_put(tr);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Don't let event modules unload while in use */
+	ret = trace_event_try_get_ref(file->event_call);
+	if (!ret) {
+		trace_array_put(tr);
+		ret = -EBUSY;
+		goto out;
+	}
+
+	ret = 0;
+ out:
+	mutex_unlock(&event_mutex);
+
+	if (ret)
+		file = ERR_PTR(ret);
+
+	return file;
+}
+EXPORT_SYMBOL_GPL(trace_get_event_file);
+
+/**
+ * trace_put_event_file - Release a file from trace_get_event_file()
+ * @file: The trace event file
+ *
+ * If a file was retrieved using trace_get_event_file(), this should
+ * be called when it's no longer needed.  It will cancel the previous
+ * trace_array_get() called by that function, and decrement the
+ * event's module refcount.
+ */
+void trace_put_event_file(struct trace_event_file *file)
+{
+	mutex_lock(&event_mutex);
+	trace_event_put_ref(file->event_call);
+	mutex_unlock(&event_mutex);
+
+	trace_array_put(file->tr);
+}
+EXPORT_SYMBOL_GPL(trace_put_event_file);
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+/* Avoid typos */
+#define ENABLE_EVENT_STR	"enable_event"
+#define DISABLE_EVENT_STR	"disable_event"
+
+struct event_probe_data {
+	struct trace_event_file	*file;
+	unsigned long			count;
+	int				ref;
+	bool				enable;
+};
+
+static void update_event_probe(struct event_probe_data *data)
+{
+	if (data->enable)
+		clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
+	else
+		set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
+}
+
+static void
+event_enable_probe(unsigned long ip, unsigned long parent_ip,
+		   struct trace_array *tr, struct ftrace_probe_ops *ops,
+		   void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+	struct event_probe_data *edata;
+	void **pdata;
+
+	pdata = ftrace_func_mapper_find_ip(mapper, ip);
+	if (!pdata || !*pdata)
+		return;
+
+	edata = *pdata;
+	update_event_probe(edata);
+}
+
+static void
+event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
+			 struct trace_array *tr, struct ftrace_probe_ops *ops,
+			 void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+	struct event_probe_data *edata;
+	void **pdata;
+
+	pdata = ftrace_func_mapper_find_ip(mapper, ip);
+	if (!pdata || !*pdata)
+		return;
+
+	edata = *pdata;
+
+	if (!edata->count)
+		return;
+
+	/* Skip if the event is in a state we want to switch to */
+	if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
+		return;
+
+	if (edata->count != -1)
+		(edata->count)--;
+
+	update_event_probe(edata);
+}
+
+static int
+event_enable_print(struct seq_file *m, unsigned long ip,
+		   struct ftrace_probe_ops *ops, void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+	struct event_probe_data *edata;
+	void **pdata;
+
+	pdata = ftrace_func_mapper_find_ip(mapper, ip);
+
+	if (WARN_ON_ONCE(!pdata || !*pdata))
+		return 0;
+
+	edata = *pdata;
+
+	seq_printf(m, "%ps:", (void *)ip);
+
+	seq_printf(m, "%s:%s:%s",
+		   edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
+		   edata->file->event_call->class->system,
+		   trace_event_name(edata->file->event_call));
+
+	if (edata->count == -1)
+		seq_puts(m, ":unlimited\n");
+	else
+		seq_printf(m, ":count=%ld\n", edata->count);
+
+	return 0;
+}
+
+static int
+event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
+		  unsigned long ip, void *init_data, void **data)
+{
+	struct ftrace_func_mapper *mapper = *data;
+	struct event_probe_data *edata = init_data;
+	int ret;
+
+	if (!mapper) {
+		mapper = allocate_ftrace_func_mapper();
+		if (!mapper)
+			return -ENODEV;
+		*data = mapper;
+	}
+
+	ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
+	if (ret < 0)
+		return ret;
+
+	edata->ref++;
+
+	return 0;
+}
+
+static int free_probe_data(void *data)
+{
+	struct event_probe_data *edata = data;
+
+	edata->ref--;
+	if (!edata->ref) {
+		/* Remove the SOFT_MODE flag */
+		__ftrace_event_enable_disable(edata->file, 0, 1);
+		trace_event_put_ref(edata->file->event_call);
+		kfree(edata);
+	}
+	return 0;
+}
+
+static void
+event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
+		  unsigned long ip, void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+	struct event_probe_data *edata;
+
+	if (!ip) {
+		if (!mapper)
+			return;
+		free_ftrace_func_mapper(mapper, free_probe_data);
+		return;
+	}
+
+	edata = ftrace_func_mapper_remove_ip(mapper, ip);
+
+	if (WARN_ON_ONCE(!edata))
+		return;
+
+	if (WARN_ON_ONCE(edata->ref <= 0))
+		return;
+
+	free_probe_data(edata);
+}
+
+static struct ftrace_probe_ops event_enable_probe_ops = {
+	.func			= event_enable_probe,
+	.print			= event_enable_print,
+	.init			= event_enable_init,
+	.free			= event_enable_free,
+};
+
+static struct ftrace_probe_ops event_enable_count_probe_ops = {
+	.func			= event_enable_count_probe,
+	.print			= event_enable_print,
+	.init			= event_enable_init,
+	.free			= event_enable_free,
+};
+
+static struct ftrace_probe_ops event_disable_probe_ops = {
+	.func			= event_enable_probe,
+	.print			= event_enable_print,
+	.init			= event_enable_init,
+	.free			= event_enable_free,
+};
+
+static struct ftrace_probe_ops event_disable_count_probe_ops = {
+	.func			= event_enable_count_probe,
+	.print			= event_enable_print,
+	.init			= event_enable_init,
+	.free			= event_enable_free,
+};
+
+static int
+event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
+		  char *glob, char *cmd, char *param, int enabled)
+{
+	struct trace_event_file *file;
+	struct ftrace_probe_ops *ops;
+	struct event_probe_data *data;
+	const char *system;
+	const char *event;
+	char *number;
+	bool enable;
+	int ret;
+
+	if (!tr)
+		return -ENODEV;
+
+	/* hash funcs only work with set_ftrace_filter */
+	if (!enabled || !param)
+		return -EINVAL;
+
+	system = strsep(&param, ":");
+	if (!param)
+		return -EINVAL;
+
+	event = strsep(&param, ":");
+
+	mutex_lock(&event_mutex);
+
+	ret = -EINVAL;
+	file = find_event_file(tr, system, event);
+	if (!file)
+		goto out;
+
+	enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
+
+	if (enable)
+		ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
+	else
+		ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
+
+	if (glob[0] == '!') {
+		ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
+		goto out;
+	}
+
+	ret = -ENOMEM;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		goto out;
+
+	data->enable = enable;
+	data->count = -1;
+	data->file = file;
+
+	if (!param)
+		goto out_reg;
+
+	number = strsep(&param, ":");
+
+	ret = -EINVAL;
+	if (!strlen(number))
+		goto out_free;
+
+	/*
+	 * We use the callback data field (which is a pointer)
+	 * as our counter.
+	 */
+	ret = kstrtoul(number, 0, &data->count);
+	if (ret)
+		goto out_free;
+
+ out_reg:
+	/* Don't let event modules unload while probe registered */
+	ret = trace_event_try_get_ref(file->event_call);
+	if (!ret) {
+		ret = -EBUSY;
+		goto out_free;
+	}
+
+	ret = __ftrace_event_enable_disable(file, 1, 1);
+	if (ret < 0)
+		goto out_put;
+
+	ret = register_ftrace_function_probe(glob, tr, ops, data);
+	/*
+	 * The above returns on success the # of functions enabled,
+	 * but if it didn't find any functions it returns zero.
+	 * Consider no functions a failure too.
+	 */
+	if (!ret) {
+		ret = -ENOENT;
+		goto out_disable;
+	} else if (ret < 0)
+		goto out_disable;
+	/* Just return zero, not the number of enabled functions */
+	ret = 0;
+ out:
+	mutex_unlock(&event_mutex);
+	return ret;
+
+ out_disable:
+	__ftrace_event_enable_disable(file, 0, 1);
+ out_put:
+	trace_event_put_ref(file->event_call);
+ out_free:
+	kfree(data);
+	goto out;
+}
+
+static struct ftrace_func_command event_enable_cmd = {
+	.name			= ENABLE_EVENT_STR,
+	.func			= event_enable_func,
+};
+
+static struct ftrace_func_command event_disable_cmd = {
+	.name			= DISABLE_EVENT_STR,
+	.func			= event_enable_func,
+};
+
+static __init int register_event_cmds(void)
+{
+	int ret;
+
+	ret = register_ftrace_command(&event_enable_cmd);
+	if (WARN_ON(ret < 0))
+		return ret;
+	ret = register_ftrace_command(&event_disable_cmd);
+	if (WARN_ON(ret < 0))
+		unregister_ftrace_command(&event_enable_cmd);
+	return ret;
+}
+#else
+static inline int register_event_cmds(void) { return 0; }
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+/*
+ * The top level array and trace arrays created by boot-time tracing
+ * have already had its trace_event_file descriptors created in order
+ * to allow for early events to be recorded.
+ * This function is called after the tracefs has been initialized,
+ * and we now have to create the files associated to the events.
+ */
+static void __trace_early_add_event_dirs(struct trace_array *tr)
+{
+	struct trace_event_file *file;
+	int ret;
+
+
+	list_for_each_entry(file, &tr->events, list) {
+		ret = event_create_dir(tr->event_dir, file);
+		if (ret < 0)
+			pr_warn("Could not create directory for event %s\n",
+				trace_event_name(file->event_call));
+	}
+}
+
+/*
+ * For early boot up, the top trace array and the trace arrays created
+ * by boot-time tracing require to have a list of events that can be
+ * enabled. This must be done before the filesystem is set up in order
+ * to allow events to be traced early.
+ */
+void __trace_early_add_events(struct trace_array *tr)
+{
+	struct trace_event_call *call;
+	int ret;
+
+	list_for_each_entry(call, &ftrace_events, list) {
+		/* Early boot up should not have any modules loaded */
+		if (!(call->flags & TRACE_EVENT_FL_DYNAMIC) &&
+		    WARN_ON_ONCE(call->module))
+			continue;
+
+		ret = __trace_early_add_new_event(call, tr);
+		if (ret < 0)
+			pr_warn("Could not create early event %s\n",
+				trace_event_name(call));
+	}
+}
+
+/* Remove the event directory structure for a trace directory. */
+static void
+__trace_remove_event_dirs(struct trace_array *tr)
+{
+	struct trace_event_file *file, *next;
+
+	list_for_each_entry_safe(file, next, &tr->events, list)
+		remove_event_file_dir(file);
+}
+
+static void __add_event_to_tracers(struct trace_event_call *call)
+{
+	struct trace_array *tr;
+
+	list_for_each_entry(tr, &ftrace_trace_arrays, list)
+		__trace_add_new_event(call, tr);
+}
+
+extern struct trace_event_call *__start_ftrace_events[];
+extern struct trace_event_call *__stop_ftrace_events[];
+
+static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
+
+static __init int setup_trace_event(char *str)
+{
+	strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
+	ring_buffer_expanded = true;
+	disable_tracing_selftest("running event tracing");
+
+	return 1;
+}
+__setup("trace_event=", setup_trace_event);
+
+/* Expects to have event_mutex held when called */
+static int
+create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
+{
+	struct dentry *d_events;
+	struct dentry *entry;
+
+	entry = trace_create_file("set_event", TRACE_MODE_WRITE, parent,
+				  tr, &ftrace_set_event_fops);
+	if (!entry)
+		return -ENOMEM;
+
+	d_events = tracefs_create_dir("events", parent);
+	if (!d_events) {
+		pr_warn("Could not create tracefs 'events' directory\n");
+		return -ENOMEM;
+	}
+
+	entry = trace_create_file("enable", TRACE_MODE_WRITE, d_events,
+				  tr, &ftrace_tr_enable_fops);
+	if (!entry)
+		return -ENOMEM;
+
+	/* There are not as crucial, just warn if they are not created */
+
+	trace_create_file("set_event_pid", TRACE_MODE_WRITE, parent,
+			  tr, &ftrace_set_event_pid_fops);
+
+	trace_create_file("set_event_notrace_pid",
+			  TRACE_MODE_WRITE, parent, tr,
+			  &ftrace_set_event_notrace_pid_fops);
+
+	/* ring buffer internal formats */
+	trace_create_file("header_page", TRACE_MODE_READ, d_events,
+				  ring_buffer_print_page_header,
+				  &ftrace_show_header_fops);
+
+	trace_create_file("header_event", TRACE_MODE_READ, d_events,
+				  ring_buffer_print_entry_header,
+				  &ftrace_show_header_fops);
+
+	tr->event_dir = d_events;
+
+	return 0;
+}
+
+/**
+ * event_trace_add_tracer - add a instance of a trace_array to events
+ * @parent: The parent dentry to place the files/directories for events in
+ * @tr: The trace array associated with these events
+ *
+ * When a new instance is created, it needs to set up its events
+ * directory, as well as other files associated with events. It also
+ * creates the event hierarchy in the @parent/events directory.
+ *
+ * Returns 0 on success.
+ *
+ * Must be called with event_mutex held.
+ */
+int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
+{
+	int ret;
+
+	lockdep_assert_held(&event_mutex);
+
+	ret = create_event_toplevel_files(parent, tr);
+	if (ret)
+		goto out;
+
+	down_write(&trace_event_sem);
+	/* If tr already has the event list, it is initialized in early boot. */
+	if (unlikely(!list_empty(&tr->events)))
+		__trace_early_add_event_dirs(tr);
+	else
+		__trace_add_event_dirs(tr);
+	up_write(&trace_event_sem);
+
+ out:
+	return ret;
+}
+
+/*
+ * The top trace array already had its file descriptors created.
+ * Now the files themselves need to be created.
+ */
+static __init int
+early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
+{
+	int ret;
+
+	mutex_lock(&event_mutex);
+
+	ret = create_event_toplevel_files(parent, tr);
+	if (ret)
+		goto out_unlock;
+
+	down_write(&trace_event_sem);
+	__trace_early_add_event_dirs(tr);
+	up_write(&trace_event_sem);
+
+ out_unlock:
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+/* Must be called with event_mutex held */
+int event_trace_del_tracer(struct trace_array *tr)
+{
+	lockdep_assert_held(&event_mutex);
+
+	/* Disable any event triggers and associated soft-disabled events */
+	clear_event_triggers(tr);
+
+	/* Clear the pid list */
+	__ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
+
+	/* Disable any running events */
+	__ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
+
+	/* Make sure no more events are being executed */
+	tracepoint_synchronize_unregister();
+
+	down_write(&trace_event_sem);
+	__trace_remove_event_dirs(tr);
+	tracefs_remove(tr->event_dir);
+	up_write(&trace_event_sem);
+
+	tr->event_dir = NULL;
+
+	return 0;
+}
+
+static __init int event_trace_memsetup(void)
+{
+	field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
+	file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
+	return 0;
+}
+
+static __init void
+early_enable_events(struct trace_array *tr, bool disable_first)
+{
+	char *buf = bootup_event_buf;
+	char *token;
+	int ret;
+
+	while (true) {
+		token = strsep(&buf, ",");
+
+		if (!token)
+			break;
+
+		if (*token) {
+			/* Restarting syscalls requires that we stop them first */
+			if (disable_first)
+				ftrace_set_clr_event(tr, token, 0);
+
+			ret = ftrace_set_clr_event(tr, token, 1);
+			if (ret)
+				pr_warn("Failed to enable trace event: %s\n", token);
+		}
+
+		/* Put back the comma to allow this to be called again */
+		if (buf)
+			*(buf - 1) = ',';
+	}
+}
+
+static __init int event_trace_enable(void)
+{
+	struct trace_array *tr = top_trace_array();
+	struct trace_event_call **iter, *call;
+	int ret;
+
+	if (!tr)
+		return -ENODEV;
+
+	for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
+
+		call = *iter;
+		ret = event_init(call);
+		if (!ret)
+			list_add(&call->list, &ftrace_events);
+	}
+
+	/*
+	 * We need the top trace array to have a working set of trace
+	 * points at early init, before the debug files and directories
+	 * are created. Create the file entries now, and attach them
+	 * to the actual file dentries later.
+	 */
+	__trace_early_add_events(tr);
+
+	early_enable_events(tr, false);
+
+	trace_printk_start_comm();
+
+	register_event_cmds();
+
+	register_trigger_cmds();
+
+	return 0;
+}
+
+/*
+ * event_trace_enable() is called from trace_event_init() first to
+ * initialize events and perhaps start any events that are on the
+ * command line. Unfortunately, there are some events that will not
+ * start this early, like the system call tracepoints that need
+ * to set the %SYSCALL_WORK_SYSCALL_TRACEPOINT flag of pid 1. But
+ * event_trace_enable() is called before pid 1 starts, and this flag
+ * is never set, making the syscall tracepoint never get reached, but
+ * the event is enabled regardless (and not doing anything).
+ */
+static __init int event_trace_enable_again(void)
+{
+	struct trace_array *tr;
+
+	tr = top_trace_array();
+	if (!tr)
+		return -ENODEV;
+
+	early_enable_events(tr, true);
+
+	return 0;
+}
+
+early_initcall(event_trace_enable_again);
+
+/* Init fields which doesn't related to the tracefs */
+static __init int event_trace_init_fields(void)
+{
+	if (trace_define_generic_fields())
+		pr_warn("tracing: Failed to allocated generic fields");
+
+	if (trace_define_common_fields())
+		pr_warn("tracing: Failed to allocate common fields");
+
+	return 0;
+}
+
+__init int event_trace_init(void)
+{
+	struct trace_array *tr;
+	int ret;
+
+	tr = top_trace_array();
+	if (!tr)
+		return -ENODEV;
+
+	trace_create_file("available_events", TRACE_MODE_READ,
+			  NULL, tr, &ftrace_avail_fops);
+
+	ret = early_event_add_tracer(NULL, tr);
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_MODULES
+	ret = register_module_notifier(&trace_module_nb);
+	if (ret)
+		pr_warn("Failed to register trace events module notifier\n");
+#endif
+
+	eventdir_initialized = true;
+
+	return 0;
+}
+
+void __init trace_event_init(void)
+{
+	event_trace_memsetup();
+	init_ftrace_syscalls();
+	event_trace_enable();
+	event_trace_init_fields();
+}
+
+#ifdef CONFIG_EVENT_TRACE_STARTUP_TEST
+
+static DEFINE_SPINLOCK(test_spinlock);
+static DEFINE_SPINLOCK(test_spinlock_irq);
+static DEFINE_MUTEX(test_mutex);
+
+static __init void test_work(struct work_struct *dummy)
+{
+	spin_lock(&test_spinlock);
+	spin_lock_irq(&test_spinlock_irq);
+	udelay(1);
+	spin_unlock_irq(&test_spinlock_irq);
+	spin_unlock(&test_spinlock);
+
+	mutex_lock(&test_mutex);
+	msleep(1);
+	mutex_unlock(&test_mutex);
+}
+
+static __init int event_test_thread(void *unused)
+{
+	void *test_malloc;
+
+	test_malloc = kmalloc(1234, GFP_KERNEL);
+	if (!test_malloc)
+		pr_info("failed to kmalloc\n");
+
+	schedule_on_each_cpu(test_work);
+
+	kfree(test_malloc);
+
+	set_current_state(TASK_INTERRUPTIBLE);
+	while (!kthread_should_stop()) {
+		schedule();
+		set_current_state(TASK_INTERRUPTIBLE);
+	}
+	__set_current_state(TASK_RUNNING);
+
+	return 0;
+}
+
+/*
+ * Do various things that may trigger events.
+ */
+static __init void event_test_stuff(void)
+{
+	struct task_struct *test_thread;
+
+	test_thread = kthread_run(event_test_thread, NULL, "test-events");
+	msleep(1);
+	kthread_stop(test_thread);
+}
+
+/*
+ * For every trace event defined, we will test each trace point separately,
+ * and then by groups, and finally all trace points.
+ */
+static __init void event_trace_self_tests(void)
+{
+	struct trace_subsystem_dir *dir;
+	struct trace_event_file *file;
+	struct trace_event_call *call;
+	struct event_subsystem *system;
+	struct trace_array *tr;
+	int ret;
+
+	tr = top_trace_array();
+	if (!tr)
+		return;
+
+	pr_info("Running tests on trace events:\n");
+
+	list_for_each_entry(file, &tr->events, list) {
+
+		call = file->event_call;
+
+		/* Only test those that have a probe */
+		if (!call->class || !call->class->probe)
+			continue;
+
+/*
+ * Testing syscall events here is pretty useless, but
+ * we still do it if configured. But this is time consuming.
+ * What we really need is a user thread to perform the
+ * syscalls as we test.
+ */
+#ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
+		if (call->class->system &&
+		    strcmp(call->class->system, "syscalls") == 0)
+			continue;
+#endif
+
+		pr_info("Testing event %s: ", trace_event_name(call));
+
+		/*
+		 * If an event is already enabled, someone is using
+		 * it and the self test should not be on.
+		 */
+		if (file->flags & EVENT_FILE_FL_ENABLED) {
+			pr_warn("Enabled event during self test!\n");
+			WARN_ON_ONCE(1);
+			continue;
+		}
+
+		ftrace_event_enable_disable(file, 1);
+		event_test_stuff();
+		ftrace_event_enable_disable(file, 0);
+
+		pr_cont("OK\n");
+	}
+
+	/* Now test at the sub system level */
+
+	pr_info("Running tests on trace event systems:\n");
+
+	list_for_each_entry(dir, &tr->systems, list) {
+
+		system = dir->subsystem;
+
+		/* the ftrace system is special, skip it */
+		if (strcmp(system->name, "ftrace") == 0)
+			continue;
+
+		pr_info("Testing event system %s: ", system->name);
+
+		ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
+		if (WARN_ON_ONCE(ret)) {
+			pr_warn("error enabling system %s\n",
+				system->name);
+			continue;
+		}
+
+		event_test_stuff();
+
+		ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
+		if (WARN_ON_ONCE(ret)) {
+			pr_warn("error disabling system %s\n",
+				system->name);
+			continue;
+		}
+
+		pr_cont("OK\n");
+	}
+
+	/* Test with all events enabled */
+
+	pr_info("Running tests on all trace events:\n");
+	pr_info("Testing all events: ");
+
+	ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
+	if (WARN_ON_ONCE(ret)) {
+		pr_warn("error enabling all events\n");
+		return;
+	}
+
+	event_test_stuff();
+
+	/* reset sysname */
+	ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
+	if (WARN_ON_ONCE(ret)) {
+		pr_warn("error disabling all events\n");
+		return;
+	}
+
+	pr_cont("OK\n");
+}
+
+#ifdef CONFIG_FUNCTION_TRACER
+
+static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
+
+static struct trace_event_file event_trace_file __initdata;
+
+static void __init
+function_test_events_call(unsigned long ip, unsigned long parent_ip,
+			  struct ftrace_ops *op, struct ftrace_regs *regs)
+{
+	struct trace_buffer *buffer;
+	struct ring_buffer_event *event;
+	struct ftrace_entry *entry;
+	unsigned int trace_ctx;
+	long disabled;
+	int cpu;
+
+	trace_ctx = tracing_gen_ctx();
+	preempt_disable_notrace();
+	cpu = raw_smp_processor_id();
+	disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
+
+	if (disabled != 1)
+		goto out;
+
+	event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
+						TRACE_FN, sizeof(*entry),
+						trace_ctx);
+	if (!event)
+		goto out;
+	entry	= ring_buffer_event_data(event);
+	entry->ip			= ip;
+	entry->parent_ip		= parent_ip;
+
+	event_trigger_unlock_commit(&event_trace_file, buffer, event,
+				    entry, trace_ctx);
+ out:
+	atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
+	preempt_enable_notrace();
+}
+
+static struct ftrace_ops trace_ops __initdata  =
+{
+	.func = function_test_events_call,
+};
+
+static __init void event_trace_self_test_with_function(void)
+{
+	int ret;
+
+	event_trace_file.tr = top_trace_array();
+	if (WARN_ON(!event_trace_file.tr))
+		return;
+
+	ret = register_ftrace_function(&trace_ops);
+	if (WARN_ON(ret < 0)) {
+		pr_info("Failed to enable function tracer for event tests\n");
+		return;
+	}
+	pr_info("Running tests again, along with the function tracer\n");
+	event_trace_self_tests();
+	unregister_ftrace_function(&trace_ops);
+}
+#else
+static __init void event_trace_self_test_with_function(void)
+{
+}
+#endif
+
+static __init int event_trace_self_tests_init(void)
+{
+	if (!tracing_selftest_disabled) {
+		event_trace_self_tests();
+		event_trace_self_test_with_function();
+	}
+
+	return 0;
+}
+
+late_initcall(event_trace_self_tests_init);
+
+#endif
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
new file mode 100644
index 000000000..86a0531ef
--- /dev/null
+++ b/kernel/trace/trace_events_filter.c
@@ -0,0 +1,2475 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_events_filter - generic event filtering
+ *
+ * Copyright (C) 2009 Tom Zanussi <tzanussi@gmail.com>
+ */
+
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/mutex.h>
+#include <linux/perf_event.h>
+#include <linux/slab.h>
+
+#include "trace.h"
+#include "trace_output.h"
+
+#define DEFAULT_SYS_FILTER_MESSAGE					\
+	"### global filter ###\n"					\
+	"# Use this to set filters for multiple events.\n"		\
+	"# Only events with the given fields will be affected.\n"	\
+	"# If no events are modified, an error message will be displayed here"
+
+/* Due to token parsing '<=' must be before '<' and '>=' must be before '>' */
+#define OPS					\
+	C( OP_GLOB,	"~"  ),			\
+	C( OP_NE,	"!=" ),			\
+	C( OP_EQ,	"==" ),			\
+	C( OP_LE,	"<=" ),			\
+	C( OP_LT,	"<"  ),			\
+	C( OP_GE,	">=" ),			\
+	C( OP_GT,	">"  ),			\
+	C( OP_BAND,	"&"  ),			\
+	C( OP_MAX,	NULL )
+
+#undef C
+#define C(a, b)	a
+
+enum filter_op_ids { OPS };
+
+#undef C
+#define C(a, b)	b
+
+static const char * ops[] = { OPS };
+
+enum filter_pred_fn {
+	FILTER_PRED_FN_NOP,
+	FILTER_PRED_FN_64,
+	FILTER_PRED_FN_S64,
+	FILTER_PRED_FN_U64,
+	FILTER_PRED_FN_32,
+	FILTER_PRED_FN_S32,
+	FILTER_PRED_FN_U32,
+	FILTER_PRED_FN_16,
+	FILTER_PRED_FN_S16,
+	FILTER_PRED_FN_U16,
+	FILTER_PRED_FN_8,
+	FILTER_PRED_FN_S8,
+	FILTER_PRED_FN_U8,
+	FILTER_PRED_FN_COMM,
+	FILTER_PRED_FN_STRING,
+	FILTER_PRED_FN_STRLOC,
+	FILTER_PRED_FN_STRRELLOC,
+	FILTER_PRED_FN_PCHAR_USER,
+	FILTER_PRED_FN_PCHAR,
+	FILTER_PRED_FN_CPU,
+	FILTER_PRED_FN_,
+	FILTER_PRED_TEST_VISITED,
+};
+
+struct filter_pred {
+	enum filter_pred_fn 	fn_num;
+	u64 			val;
+	struct regex		regex;
+	unsigned short		*ops;
+	struct ftrace_event_field *field;
+	int 			offset;
+	int			not;
+	int 			op;
+};
+
+/*
+ * pred functions are OP_LE, OP_LT, OP_GE, OP_GT, and OP_BAND
+ * pred_funcs_##type below must match the order of them above.
+ */
+#define PRED_FUNC_START			OP_LE
+#define PRED_FUNC_MAX			(OP_BAND - PRED_FUNC_START)
+
+#define ERRORS								\
+	C(NONE,			"No error"),				\
+	C(INVALID_OP,		"Invalid operator"),			\
+	C(TOO_MANY_OPEN,	"Too many '('"),			\
+	C(TOO_MANY_CLOSE,	"Too few '('"),				\
+	C(MISSING_QUOTE,	"Missing matching quote"),		\
+	C(OPERAND_TOO_LONG,	"Operand too long"),			\
+	C(EXPECT_STRING,	"Expecting string field"),		\
+	C(EXPECT_DIGIT,		"Expecting numeric field"),		\
+	C(ILLEGAL_FIELD_OP,	"Illegal operation for field type"),	\
+	C(FIELD_NOT_FOUND,	"Field not found"),			\
+	C(ILLEGAL_INTVAL,	"Illegal integer value"),		\
+	C(BAD_SUBSYS_FILTER,	"Couldn't find or set field in one of a subsystem's events"), \
+	C(TOO_MANY_PREDS,	"Too many terms in predicate expression"), \
+	C(INVALID_FILTER,	"Meaningless filter expression"),	\
+	C(IP_FIELD_ONLY,	"Only 'ip' field is supported for function trace"), \
+	C(INVALID_VALUE,	"Invalid value (did you forget quotes)?"), \
+	C(ERRNO,		"Error"),				\
+	C(NO_FILTER,		"No filter found")
+
+#undef C
+#define C(a, b)		FILT_ERR_##a
+
+enum { ERRORS };
+
+#undef C
+#define C(a, b)		b
+
+static const char *err_text[] = { ERRORS };
+
+/* Called after a '!' character but "!=" and "!~" are not "not"s */
+static bool is_not(const char *str)
+{
+	switch (str[1]) {
+	case '=':
+	case '~':
+		return false;
+	}
+	return true;
+}
+
+/**
+ * prog_entry - a singe entry in the filter program
+ * @target:	     Index to jump to on a branch (actually one minus the index)
+ * @when_to_branch:  The value of the result of the predicate to do a branch
+ * @pred:	     The predicate to execute.
+ */
+struct prog_entry {
+	int			target;
+	int			when_to_branch;
+	struct filter_pred	*pred;
+};
+
+/**
+ * update_preds- assign a program entry a label target
+ * @prog: The program array
+ * @N: The index of the current entry in @prog
+ * @when_to_branch: What to assign a program entry for its branch condition
+ *
+ * The program entry at @N has a target that points to the index of a program
+ * entry that can have its target and when_to_branch fields updated.
+ * Update the current program entry denoted by index @N target field to be
+ * that of the updated entry. This will denote the entry to update if
+ * we are processing an "||" after an "&&"
+ */
+static void update_preds(struct prog_entry *prog, int N, int invert)
+{
+	int t, s;
+
+	t = prog[N].target;
+	s = prog[t].target;
+	prog[t].when_to_branch = invert;
+	prog[t].target = N;
+	prog[N].target = s;
+}
+
+struct filter_parse_error {
+	int lasterr;
+	int lasterr_pos;
+};
+
+static void parse_error(struct filter_parse_error *pe, int err, int pos)
+{
+	pe->lasterr = err;
+	pe->lasterr_pos = pos;
+}
+
+typedef int (*parse_pred_fn)(const char *str, void *data, int pos,
+			     struct filter_parse_error *pe,
+			     struct filter_pred **pred);
+
+enum {
+	INVERT		= 1,
+	PROCESS_AND	= 2,
+	PROCESS_OR	= 4,
+};
+
+/*
+ * Without going into a formal proof, this explains the method that is used in
+ * parsing the logical expressions.
+ *
+ * For example, if we have: "a && !(!b || (c && g)) || d || e && !f"
+ * The first pass will convert it into the following program:
+ *
+ * n1: r=a;       l1: if (!r) goto l4;
+ * n2: r=b;       l2: if (!r) goto l4;
+ * n3: r=c; r=!r; l3: if (r) goto l4;
+ * n4: r=g; r=!r; l4: if (r) goto l5;
+ * n5: r=d;       l5: if (r) goto T
+ * n6: r=e;       l6: if (!r) goto l7;
+ * n7: r=f; r=!r; l7: if (!r) goto F
+ * T: return TRUE
+ * F: return FALSE
+ *
+ * To do this, we use a data structure to represent each of the above
+ * predicate and conditions that has:
+ *
+ *  predicate, when_to_branch, invert, target
+ *
+ * The "predicate" will hold the function to determine the result "r".
+ * The "when_to_branch" denotes what "r" should be if a branch is to be taken
+ * "&&" would contain "!r" or (0) and "||" would contain "r" or (1).
+ * The "invert" holds whether the value should be reversed before testing.
+ * The "target" contains the label "l#" to jump to.
+ *
+ * A stack is created to hold values when parentheses are used.
+ *
+ * To simplify the logic, the labels will start at 0 and not 1.
+ *
+ * The possible invert values are 1 and 0. The number of "!"s that are in scope
+ * before the predicate determines the invert value, if the number is odd then
+ * the invert value is 1 and 0 otherwise. This means the invert value only
+ * needs to be toggled when a new "!" is introduced compared to what is stored
+ * on the stack, where parentheses were used.
+ *
+ * The top of the stack and "invert" are initialized to zero.
+ *
+ * ** FIRST PASS **
+ *
+ * #1 A loop through all the tokens is done:
+ *
+ * #2 If the token is an "(", the stack is push, and the current stack value
+ *    gets the current invert value, and the loop continues to the next token.
+ *    The top of the stack saves the "invert" value to keep track of what
+ *    the current inversion is. As "!(a && !b || c)" would require all
+ *    predicates being affected separately by the "!" before the parentheses.
+ *    And that would end up being equivalent to "(!a || b) && !c"
+ *
+ * #3 If the token is an "!", the current "invert" value gets inverted, and
+ *    the loop continues. Note, if the next token is a predicate, then
+ *    this "invert" value is only valid for the current program entry,
+ *    and does not affect other predicates later on.
+ *
+ * The only other acceptable token is the predicate string.
+ *
+ * #4 A new entry into the program is added saving: the predicate and the
+ *    current value of "invert". The target is currently assigned to the
+ *    previous program index (this will not be its final value).
+ *
+ * #5 We now enter another loop and look at the next token. The only valid
+ *    tokens are ")", "&&", "||" or end of the input string "\0".
+ *
+ * #6 The invert variable is reset to the current value saved on the top of
+ *    the stack.
+ *
+ * #7 The top of the stack holds not only the current invert value, but also
+ *    if a "&&" or "||" needs to be processed. Note, the "&&" takes higher
+ *    precedence than "||". That is "a && b || c && d" is equivalent to
+ *    "(a && b) || (c && d)". Thus the first thing to do is to see if "&&" needs
+ *    to be processed. This is the case if an "&&" was the last token. If it was
+ *    then we call update_preds(). This takes the program, the current index in
+ *    the program, and the current value of "invert".  More will be described
+ *    below about this function.
+ *
+ * #8 If the next token is "&&" then we set a flag in the top of the stack
+ *    that denotes that "&&" needs to be processed, break out of this loop
+ *    and continue with the outer loop.
+ *
+ * #9 Otherwise, if a "||" needs to be processed then update_preds() is called.
+ *    This is called with the program, the current index in the program, but
+ *    this time with an inverted value of "invert" (that is !invert). This is
+ *    because the value taken will become the "when_to_branch" value of the
+ *    program.
+ *    Note, this is called when the next token is not an "&&". As stated before,
+ *    "&&" takes higher precedence, and "||" should not be processed yet if the
+ *    next logical operation is "&&".
+ *
+ * #10 If the next token is "||" then we set a flag in the top of the stack
+ *     that denotes that "||" needs to be processed, break out of this loop
+ *     and continue with the outer loop.
+ *
+ * #11 If this is the end of the input string "\0" then we break out of both
+ *     loops.
+ *
+ * #12 Otherwise, the next token is ")", where we pop the stack and continue
+ *     this inner loop.
+ *
+ * Now to discuss the update_pred() function, as that is key to the setting up
+ * of the program. Remember the "target" of the program is initialized to the
+ * previous index and not the "l" label. The target holds the index into the
+ * program that gets affected by the operand. Thus if we have something like
+ *  "a || b && c", when we process "a" the target will be "-1" (undefined).
+ * When we process "b", its target is "0", which is the index of "a", as that's
+ * the predicate that is affected by "||". But because the next token after "b"
+ * is "&&" we don't call update_preds(). Instead continue to "c". As the
+ * next token after "c" is not "&&" but the end of input, we first process the
+ * "&&" by calling update_preds() for the "&&" then we process the "||" by
+ * calling updates_preds() with the values for processing "||".
+ *
+ * What does that mean? What update_preds() does is to first save the "target"
+ * of the program entry indexed by the current program entry's "target"
+ * (remember the "target" is initialized to previous program entry), and then
+ * sets that "target" to the current index which represents the label "l#".
+ * That entry's "when_to_branch" is set to the value passed in (the "invert"
+ * or "!invert"). Then it sets the current program entry's target to the saved
+ * "target" value (the old value of the program that had its "target" updated
+ * to the label).
+ *
+ * Looking back at "a || b && c", we have the following steps:
+ *  "a"  - prog[0] = { "a", X, -1 } // pred, when_to_branch, target
+ *  "||" - flag that we need to process "||"; continue outer loop
+ *  "b"  - prog[1] = { "b", X, 0 }
+ *  "&&" - flag that we need to process "&&"; continue outer loop
+ * (Notice we did not process "||")
+ *  "c"  - prog[2] = { "c", X, 1 }
+ *  update_preds(prog, 2, 0); // invert = 0 as we are processing "&&"
+ *    t = prog[2].target; // t = 1
+ *    s = prog[t].target; // s = 0
+ *    prog[t].target = 2; // Set target to "l2"
+ *    prog[t].when_to_branch = 0;
+ *    prog[2].target = s;
+ * update_preds(prog, 2, 1); // invert = 1 as we are now processing "||"
+ *    t = prog[2].target; // t = 0
+ *    s = prog[t].target; // s = -1
+ *    prog[t].target = 2; // Set target to "l2"
+ *    prog[t].when_to_branch = 1;
+ *    prog[2].target = s;
+ *
+ * #13 Which brings us to the final step of the first pass, which is to set
+ *     the last program entry's when_to_branch and target, which will be
+ *     when_to_branch = 0; target = N; ( the label after the program entry after
+ *     the last program entry processed above).
+ *
+ * If we denote "TRUE" to be the entry after the last program entry processed,
+ * and "FALSE" the program entry after that, we are now done with the first
+ * pass.
+ *
+ * Making the above "a || b && c" have a program of:
+ *  prog[0] = { "a", 1, 2 }
+ *  prog[1] = { "b", 0, 2 }
+ *  prog[2] = { "c", 0, 3 }
+ *
+ * Which translates into:
+ * n0: r = a; l0: if (r) goto l2;
+ * n1: r = b; l1: if (!r) goto l2;
+ * n2: r = c; l2: if (!r) goto l3;  // Which is the same as "goto F;"
+ * T: return TRUE; l3:
+ * F: return FALSE
+ *
+ * Although, after the first pass, the program is correct, it is
+ * inefficient. The simple sample of "a || b && c" could be easily been
+ * converted into:
+ * n0: r = a; if (r) goto T
+ * n1: r = b; if (!r) goto F
+ * n2: r = c; if (!r) goto F
+ * T: return TRUE;
+ * F: return FALSE;
+ *
+ * The First Pass is over the input string. The next too passes are over
+ * the program itself.
+ *
+ * ** SECOND PASS **
+ *
+ * Which brings us to the second pass. If a jump to a label has the
+ * same condition as that label, it can instead jump to its target.
+ * The original example of "a && !(!b || (c && g)) || d || e && !f"
+ * where the first pass gives us:
+ *
+ * n1: r=a;       l1: if (!r) goto l4;
+ * n2: r=b;       l2: if (!r) goto l4;
+ * n3: r=c; r=!r; l3: if (r) goto l4;
+ * n4: r=g; r=!r; l4: if (r) goto l5;
+ * n5: r=d;       l5: if (r) goto T
+ * n6: r=e;       l6: if (!r) goto l7;
+ * n7: r=f; r=!r; l7: if (!r) goto F:
+ * T: return TRUE;
+ * F: return FALSE
+ *
+ * We can see that "l3: if (r) goto l4;" and at l4, we have "if (r) goto l5;".
+ * And "l5: if (r) goto T", we could optimize this by converting l3 and l4
+ * to go directly to T. To accomplish this, we start from the last
+ * entry in the program and work our way back. If the target of the entry
+ * has the same "when_to_branch" then we could use that entry's target.
+ * Doing this, the above would end up as:
+ *
+ * n1: r=a;       l1: if (!r) goto l4;
+ * n2: r=b;       l2: if (!r) goto l4;
+ * n3: r=c; r=!r; l3: if (r) goto T;
+ * n4: r=g; r=!r; l4: if (r) goto T;
+ * n5: r=d;       l5: if (r) goto T;
+ * n6: r=e;       l6: if (!r) goto F;
+ * n7: r=f; r=!r; l7: if (!r) goto F;
+ * T: return TRUE
+ * F: return FALSE
+ *
+ * In that same pass, if the "when_to_branch" doesn't match, we can simply
+ * go to the program entry after the label. That is, "l2: if (!r) goto l4;"
+ * where "l4: if (r) goto T;", then we can convert l2 to be:
+ * "l2: if (!r) goto n5;".
+ *
+ * This will have the second pass give us:
+ * n1: r=a;       l1: if (!r) goto n5;
+ * n2: r=b;       l2: if (!r) goto n5;
+ * n3: r=c; r=!r; l3: if (r) goto T;
+ * n4: r=g; r=!r; l4: if (r) goto T;
+ * n5: r=d;       l5: if (r) goto T
+ * n6: r=e;       l6: if (!r) goto F;
+ * n7: r=f; r=!r; l7: if (!r) goto F
+ * T: return TRUE
+ * F: return FALSE
+ *
+ * Notice, all the "l#" labels are no longer used, and they can now
+ * be discarded.
+ *
+ * ** THIRD PASS **
+ *
+ * For the third pass we deal with the inverts. As they simply just
+ * make the "when_to_branch" get inverted, a simple loop over the
+ * program to that does: "when_to_branch ^= invert;" will do the
+ * job, leaving us with:
+ * n1: r=a; if (!r) goto n5;
+ * n2: r=b; if (!r) goto n5;
+ * n3: r=c: if (!r) goto T;
+ * n4: r=g; if (!r) goto T;
+ * n5: r=d; if (r) goto T
+ * n6: r=e; if (!r) goto F;
+ * n7: r=f; if (r) goto F
+ * T: return TRUE
+ * F: return FALSE
+ *
+ * As "r = a; if (!r) goto n5;" is obviously the same as
+ * "if (!a) goto n5;" without doing anything we can interpret the
+ * program as:
+ * n1: if (!a) goto n5;
+ * n2: if (!b) goto n5;
+ * n3: if (!c) goto T;
+ * n4: if (!g) goto T;
+ * n5: if (d) goto T
+ * n6: if (!e) goto F;
+ * n7: if (f) goto F
+ * T: return TRUE
+ * F: return FALSE
+ *
+ * Since the inverts are discarded at the end, there's no reason to store
+ * them in the program array (and waste memory). A separate array to hold
+ * the inverts is used and freed at the end.
+ */
+static struct prog_entry *
+predicate_parse(const char *str, int nr_parens, int nr_preds,
+		parse_pred_fn parse_pred, void *data,
+		struct filter_parse_error *pe)
+{
+	struct prog_entry *prog_stack;
+	struct prog_entry *prog;
+	const char *ptr = str;
+	char *inverts = NULL;
+	int *op_stack;
+	int *top;
+	int invert = 0;
+	int ret = -ENOMEM;
+	int len;
+	int N = 0;
+	int i;
+
+	nr_preds += 2; /* For TRUE and FALSE */
+
+	op_stack = kmalloc_array(nr_parens, sizeof(*op_stack), GFP_KERNEL);
+	if (!op_stack)
+		return ERR_PTR(-ENOMEM);
+	prog_stack = kcalloc(nr_preds, sizeof(*prog_stack), GFP_KERNEL);
+	if (!prog_stack) {
+		parse_error(pe, -ENOMEM, 0);
+		goto out_free;
+	}
+	inverts = kmalloc_array(nr_preds, sizeof(*inverts), GFP_KERNEL);
+	if (!inverts) {
+		parse_error(pe, -ENOMEM, 0);
+		goto out_free;
+	}
+
+	top = op_stack;
+	prog = prog_stack;
+	*top = 0;
+
+	/* First pass */
+	while (*ptr) {						/* #1 */
+		const char *next = ptr++;
+
+		if (isspace(*next))
+			continue;
+
+		switch (*next) {
+		case '(':					/* #2 */
+			if (top - op_stack > nr_parens) {
+				ret = -EINVAL;
+				goto out_free;
+			}
+			*(++top) = invert;
+			continue;
+		case '!':					/* #3 */
+			if (!is_not(next))
+				break;
+			invert = !invert;
+			continue;
+		}
+
+		if (N >= nr_preds) {
+			parse_error(pe, FILT_ERR_TOO_MANY_PREDS, next - str);
+			goto out_free;
+		}
+
+		inverts[N] = invert;				/* #4 */
+		prog[N].target = N-1;
+
+		len = parse_pred(next, data, ptr - str, pe, &prog[N].pred);
+		if (len < 0) {
+			ret = len;
+			goto out_free;
+		}
+		ptr = next + len;
+
+		N++;
+
+		ret = -1;
+		while (1) {					/* #5 */
+			next = ptr++;
+			if (isspace(*next))
+				continue;
+
+			switch (*next) {
+			case ')':
+			case '\0':
+				break;
+			case '&':
+			case '|':
+				/* accepting only "&&" or "||" */
+				if (next[1] == next[0]) {
+					ptr++;
+					break;
+				}
+				fallthrough;
+			default:
+				parse_error(pe, FILT_ERR_TOO_MANY_PREDS,
+					    next - str);
+				goto out_free;
+			}
+
+			invert = *top & INVERT;
+
+			if (*top & PROCESS_AND) {		/* #7 */
+				update_preds(prog, N - 1, invert);
+				*top &= ~PROCESS_AND;
+			}
+			if (*next == '&') {			/* #8 */
+				*top |= PROCESS_AND;
+				break;
+			}
+			if (*top & PROCESS_OR) {		/* #9 */
+				update_preds(prog, N - 1, !invert);
+				*top &= ~PROCESS_OR;
+			}
+			if (*next == '|') {			/* #10 */
+				*top |= PROCESS_OR;
+				break;
+			}
+			if (!*next)				/* #11 */
+				goto out;
+
+			if (top == op_stack) {
+				ret = -1;
+				/* Too few '(' */
+				parse_error(pe, FILT_ERR_TOO_MANY_CLOSE, ptr - str);
+				goto out_free;
+			}
+			top--;					/* #12 */
+		}
+	}
+ out:
+	if (top != op_stack) {
+		/* Too many '(' */
+		parse_error(pe, FILT_ERR_TOO_MANY_OPEN, ptr - str);
+		goto out_free;
+	}
+
+	if (!N) {
+		/* No program? */
+		ret = -EINVAL;
+		parse_error(pe, FILT_ERR_NO_FILTER, ptr - str);
+		goto out_free;
+	}
+
+	prog[N].pred = NULL;					/* #13 */
+	prog[N].target = 1;		/* TRUE */
+	prog[N+1].pred = NULL;
+	prog[N+1].target = 0;		/* FALSE */
+	prog[N-1].target = N;
+	prog[N-1].when_to_branch = false;
+
+	/* Second Pass */
+	for (i = N-1 ; i--; ) {
+		int target = prog[i].target;
+		if (prog[i].when_to_branch == prog[target].when_to_branch)
+			prog[i].target = prog[target].target;
+	}
+
+	/* Third Pass */
+	for (i = 0; i < N; i++) {
+		invert = inverts[i] ^ prog[i].when_to_branch;
+		prog[i].when_to_branch = invert;
+		/* Make sure the program always moves forward */
+		if (WARN_ON(prog[i].target <= i)) {
+			ret = -EINVAL;
+			goto out_free;
+		}
+	}
+
+	kfree(op_stack);
+	kfree(inverts);
+	return prog;
+out_free:
+	kfree(op_stack);
+	kfree(inverts);
+	if (prog_stack) {
+		for (i = 0; prog_stack[i].pred; i++)
+			kfree(prog_stack[i].pred);
+		kfree(prog_stack);
+	}
+	return ERR_PTR(ret);
+}
+
+enum pred_cmp_types {
+	PRED_CMP_TYPE_NOP,
+	PRED_CMP_TYPE_LT,
+	PRED_CMP_TYPE_LE,
+	PRED_CMP_TYPE_GT,
+	PRED_CMP_TYPE_GE,
+	PRED_CMP_TYPE_BAND,
+};
+
+#define DEFINE_COMPARISON_PRED(type)					\
+static int filter_pred_##type(struct filter_pred *pred, void *event)	\
+{									\
+	switch (pred->op) {						\
+	case OP_LT: {							\
+		type *addr = (type *)(event + pred->offset);		\
+		type val = (type)pred->val;				\
+		return *addr < val;					\
+	}								\
+	case OP_LE: {					\
+		type *addr = (type *)(event + pred->offset);		\
+		type val = (type)pred->val;				\
+		return *addr <= val;					\
+	}								\
+	case OP_GT: {					\
+		type *addr = (type *)(event + pred->offset);		\
+		type val = (type)pred->val;				\
+		return *addr > val;					\
+	}								\
+	case OP_GE: {					\
+		type *addr = (type *)(event + pred->offset);		\
+		type val = (type)pred->val;				\
+		return *addr >= val;					\
+	}								\
+	case OP_BAND: {					\
+		type *addr = (type *)(event + pred->offset);		\
+		type val = (type)pred->val;				\
+		return !!(*addr & val);					\
+	}								\
+	default:							\
+		return 0;						\
+	}								\
+}
+
+#define DEFINE_EQUALITY_PRED(size)					\
+static int filter_pred_##size(struct filter_pred *pred, void *event)	\
+{									\
+	u##size *addr = (u##size *)(event + pred->offset);		\
+	u##size val = (u##size)pred->val;				\
+	int match;							\
+									\
+	match = (val == *addr) ^ pred->not;				\
+									\
+	return match;							\
+}
+
+DEFINE_COMPARISON_PRED(s64);
+DEFINE_COMPARISON_PRED(u64);
+DEFINE_COMPARISON_PRED(s32);
+DEFINE_COMPARISON_PRED(u32);
+DEFINE_COMPARISON_PRED(s16);
+DEFINE_COMPARISON_PRED(u16);
+DEFINE_COMPARISON_PRED(s8);
+DEFINE_COMPARISON_PRED(u8);
+
+DEFINE_EQUALITY_PRED(64);
+DEFINE_EQUALITY_PRED(32);
+DEFINE_EQUALITY_PRED(16);
+DEFINE_EQUALITY_PRED(8);
+
+/* user space strings temp buffer */
+#define USTRING_BUF_SIZE	1024
+
+struct ustring_buffer {
+	char		buffer[USTRING_BUF_SIZE];
+};
+
+static __percpu struct ustring_buffer *ustring_per_cpu;
+
+static __always_inline char *test_string(char *str)
+{
+	struct ustring_buffer *ubuf;
+	char *kstr;
+
+	if (!ustring_per_cpu)
+		return NULL;
+
+	ubuf = this_cpu_ptr(ustring_per_cpu);
+	kstr = ubuf->buffer;
+
+	/* For safety, do not trust the string pointer */
+	if (!strncpy_from_kernel_nofault(kstr, str, USTRING_BUF_SIZE))
+		return NULL;
+	return kstr;
+}
+
+static __always_inline char *test_ustring(char *str)
+{
+	struct ustring_buffer *ubuf;
+	char __user *ustr;
+	char *kstr;
+
+	if (!ustring_per_cpu)
+		return NULL;
+
+	ubuf = this_cpu_ptr(ustring_per_cpu);
+	kstr = ubuf->buffer;
+
+	/* user space address? */
+	ustr = (char __user *)str;
+	if (!strncpy_from_user_nofault(kstr, ustr, USTRING_BUF_SIZE))
+		return NULL;
+
+	return kstr;
+}
+
+/* Filter predicate for fixed sized arrays of characters */
+static int filter_pred_string(struct filter_pred *pred, void *event)
+{
+	char *addr = (char *)(event + pred->offset);
+	int cmp, match;
+
+	cmp = pred->regex.match(addr, &pred->regex, pred->regex.field_len);
+
+	match = cmp ^ pred->not;
+
+	return match;
+}
+
+static __always_inline int filter_pchar(struct filter_pred *pred, char *str)
+{
+	int cmp, match;
+	int len;
+
+	len = strlen(str) + 1;	/* including tailing '\0' */
+	cmp = pred->regex.match(str, &pred->regex, len);
+
+	match = cmp ^ pred->not;
+
+	return match;
+}
+/* Filter predicate for char * pointers */
+static int filter_pred_pchar(struct filter_pred *pred, void *event)
+{
+	char **addr = (char **)(event + pred->offset);
+	char *str;
+
+	str = test_string(*addr);
+	if (!str)
+		return 0;
+
+	return filter_pchar(pred, str);
+}
+
+/* Filter predicate for char * pointers in user space*/
+static int filter_pred_pchar_user(struct filter_pred *pred, void *event)
+{
+	char **addr = (char **)(event + pred->offset);
+	char *str;
+
+	str = test_ustring(*addr);
+	if (!str)
+		return 0;
+
+	return filter_pchar(pred, str);
+}
+
+/*
+ * Filter predicate for dynamic sized arrays of characters.
+ * These are implemented through a list of strings at the end
+ * of the entry.
+ * Also each of these strings have a field in the entry which
+ * contains its offset from the beginning of the entry.
+ * We have then first to get this field, dereference it
+ * and add it to the address of the entry, and at last we have
+ * the address of the string.
+ */
+static int filter_pred_strloc(struct filter_pred *pred, void *event)
+{
+	u32 str_item = *(u32 *)(event + pred->offset);
+	int str_loc = str_item & 0xffff;
+	int str_len = str_item >> 16;
+	char *addr = (char *)(event + str_loc);
+	int cmp, match;
+
+	cmp = pred->regex.match(addr, &pred->regex, str_len);
+
+	match = cmp ^ pred->not;
+
+	return match;
+}
+
+/*
+ * Filter predicate for relative dynamic sized arrays of characters.
+ * These are implemented through a list of strings at the end
+ * of the entry as same as dynamic string.
+ * The difference is that the relative one records the location offset
+ * from the field itself, not the event entry.
+ */
+static int filter_pred_strrelloc(struct filter_pred *pred, void *event)
+{
+	u32 *item = (u32 *)(event + pred->offset);
+	u32 str_item = *item;
+	int str_loc = str_item & 0xffff;
+	int str_len = str_item >> 16;
+	char *addr = (char *)(&item[1]) + str_loc;
+	int cmp, match;
+
+	cmp = pred->regex.match(addr, &pred->regex, str_len);
+
+	match = cmp ^ pred->not;
+
+	return match;
+}
+
+/* Filter predicate for CPUs. */
+static int filter_pred_cpu(struct filter_pred *pred, void *event)
+{
+	int cpu, cmp;
+
+	cpu = raw_smp_processor_id();
+	cmp = pred->val;
+
+	switch (pred->op) {
+	case OP_EQ:
+		return cpu == cmp;
+	case OP_NE:
+		return cpu != cmp;
+	case OP_LT:
+		return cpu < cmp;
+	case OP_LE:
+		return cpu <= cmp;
+	case OP_GT:
+		return cpu > cmp;
+	case OP_GE:
+		return cpu >= cmp;
+	default:
+		return 0;
+	}
+}
+
+/* Filter predicate for COMM. */
+static int filter_pred_comm(struct filter_pred *pred, void *event)
+{
+	int cmp;
+
+	cmp = pred->regex.match(current->comm, &pred->regex,
+				TASK_COMM_LEN);
+	return cmp ^ pred->not;
+}
+
+/*
+ * regex_match_foo - Basic regex callbacks
+ *
+ * @str: the string to be searched
+ * @r:   the regex structure containing the pattern string
+ * @len: the length of the string to be searched (including '\0')
+ *
+ * Note:
+ * - @str might not be NULL-terminated if it's of type DYN_STRING
+ *   RDYN_STRING, or STATIC_STRING, unless @len is zero.
+ */
+
+static int regex_match_full(char *str, struct regex *r, int len)
+{
+	/* len of zero means str is dynamic and ends with '\0' */
+	if (!len)
+		return strcmp(str, r->pattern) == 0;
+
+	return strncmp(str, r->pattern, len) == 0;
+}
+
+static int regex_match_front(char *str, struct regex *r, int len)
+{
+	if (len && len < r->len)
+		return 0;
+
+	return strncmp(str, r->pattern, r->len) == 0;
+}
+
+static int regex_match_middle(char *str, struct regex *r, int len)
+{
+	if (!len)
+		return strstr(str, r->pattern) != NULL;
+
+	return strnstr(str, r->pattern, len) != NULL;
+}
+
+static int regex_match_end(char *str, struct regex *r, int len)
+{
+	int strlen = len - 1;
+
+	if (strlen >= r->len &&
+	    memcmp(str + strlen - r->len, r->pattern, r->len) == 0)
+		return 1;
+	return 0;
+}
+
+static int regex_match_glob(char *str, struct regex *r, int len __maybe_unused)
+{
+	if (glob_match(r->pattern, str))
+		return 1;
+	return 0;
+}
+
+/**
+ * filter_parse_regex - parse a basic regex
+ * @buff:   the raw regex
+ * @len:    length of the regex
+ * @search: will point to the beginning of the string to compare
+ * @not:    tell whether the match will have to be inverted
+ *
+ * This passes in a buffer containing a regex and this function will
+ * set search to point to the search part of the buffer and
+ * return the type of search it is (see enum above).
+ * This does modify buff.
+ *
+ * Returns enum type.
+ *  search returns the pointer to use for comparison.
+ *  not returns 1 if buff started with a '!'
+ *     0 otherwise.
+ */
+enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
+{
+	int type = MATCH_FULL;
+	int i;
+
+	if (buff[0] == '!') {
+		*not = 1;
+		buff++;
+		len--;
+	} else
+		*not = 0;
+
+	*search = buff;
+
+	if (isdigit(buff[0]))
+		return MATCH_INDEX;
+
+	for (i = 0; i < len; i++) {
+		if (buff[i] == '*') {
+			if (!i) {
+				type = MATCH_END_ONLY;
+			} else if (i == len - 1) {
+				if (type == MATCH_END_ONLY)
+					type = MATCH_MIDDLE_ONLY;
+				else
+					type = MATCH_FRONT_ONLY;
+				buff[i] = 0;
+				break;
+			} else {	/* pattern continues, use full glob */
+				return MATCH_GLOB;
+			}
+		} else if (strchr("[?\\", buff[i])) {
+			return MATCH_GLOB;
+		}
+	}
+	if (buff[0] == '*')
+		*search = buff + 1;
+
+	return type;
+}
+
+static void filter_build_regex(struct filter_pred *pred)
+{
+	struct regex *r = &pred->regex;
+	char *search;
+	enum regex_type type = MATCH_FULL;
+
+	if (pred->op == OP_GLOB) {
+		type = filter_parse_regex(r->pattern, r->len, &search, &pred->not);
+		r->len = strlen(search);
+		memmove(r->pattern, search, r->len+1);
+	}
+
+	switch (type) {
+	/* MATCH_INDEX should not happen, but if it does, match full */
+	case MATCH_INDEX:
+	case MATCH_FULL:
+		r->match = regex_match_full;
+		break;
+	case MATCH_FRONT_ONLY:
+		r->match = regex_match_front;
+		break;
+	case MATCH_MIDDLE_ONLY:
+		r->match = regex_match_middle;
+		break;
+	case MATCH_END_ONLY:
+		r->match = regex_match_end;
+		break;
+	case MATCH_GLOB:
+		r->match = regex_match_glob;
+		break;
+	}
+}
+
+
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+static int test_pred_visited_fn(struct filter_pred *pred, void *event);
+#else
+static int test_pred_visited_fn(struct filter_pred *pred, void *event)
+{
+	return 0;
+}
+#endif
+
+
+static int filter_pred_fn_call(struct filter_pred *pred, void *event);
+
+/* return 1 if event matches, 0 otherwise (discard) */
+int filter_match_preds(struct event_filter *filter, void *rec)
+{
+	struct prog_entry *prog;
+	int i;
+
+	/* no filter is considered a match */
+	if (!filter)
+		return 1;
+
+	/* Protected by either SRCU(tracepoint_srcu) or preempt_disable */
+	prog = rcu_dereference_raw(filter->prog);
+	if (!prog)
+		return 1;
+
+	for (i = 0; prog[i].pred; i++) {
+		struct filter_pred *pred = prog[i].pred;
+		int match = filter_pred_fn_call(pred, rec);
+		if (match == prog[i].when_to_branch)
+			i = prog[i].target;
+	}
+	return prog[i].target;
+}
+EXPORT_SYMBOL_GPL(filter_match_preds);
+
+static void remove_filter_string(struct event_filter *filter)
+{
+	if (!filter)
+		return;
+
+	kfree(filter->filter_string);
+	filter->filter_string = NULL;
+}
+
+static void append_filter_err(struct trace_array *tr,
+			      struct filter_parse_error *pe,
+			      struct event_filter *filter)
+{
+	struct trace_seq *s;
+	int pos = pe->lasterr_pos;
+	char *buf;
+	int len;
+
+	if (WARN_ON(!filter->filter_string))
+		return;
+
+	s = kmalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return;
+	trace_seq_init(s);
+
+	len = strlen(filter->filter_string);
+	if (pos > len)
+		pos = len;
+
+	/* indexing is off by one */
+	if (pos)
+		pos++;
+
+	trace_seq_puts(s, filter->filter_string);
+	if (pe->lasterr > 0) {
+		trace_seq_printf(s, "\n%*s", pos, "^");
+		trace_seq_printf(s, "\nparse_error: %s\n", err_text[pe->lasterr]);
+		tracing_log_err(tr, "event filter parse error",
+				filter->filter_string, err_text,
+				pe->lasterr, pe->lasterr_pos);
+	} else {
+		trace_seq_printf(s, "\nError: (%d)\n", pe->lasterr);
+		tracing_log_err(tr, "event filter parse error",
+				filter->filter_string, err_text,
+				FILT_ERR_ERRNO, 0);
+	}
+	trace_seq_putc(s, 0);
+	buf = kmemdup_nul(s->buffer, s->seq.len, GFP_KERNEL);
+	if (buf) {
+		kfree(filter->filter_string);
+		filter->filter_string = buf;
+	}
+	kfree(s);
+}
+
+static inline struct event_filter *event_filter(struct trace_event_file *file)
+{
+	return file->filter;
+}
+
+/* caller must hold event_mutex */
+void print_event_filter(struct trace_event_file *file, struct trace_seq *s)
+{
+	struct event_filter *filter = event_filter(file);
+
+	if (filter && filter->filter_string)
+		trace_seq_printf(s, "%s\n", filter->filter_string);
+	else
+		trace_seq_puts(s, "none\n");
+}
+
+void print_subsystem_event_filter(struct event_subsystem *system,
+				  struct trace_seq *s)
+{
+	struct event_filter *filter;
+
+	mutex_lock(&event_mutex);
+	filter = system->filter;
+	if (filter && filter->filter_string)
+		trace_seq_printf(s, "%s\n", filter->filter_string);
+	else
+		trace_seq_puts(s, DEFAULT_SYS_FILTER_MESSAGE "\n");
+	mutex_unlock(&event_mutex);
+}
+
+static void free_prog(struct event_filter *filter)
+{
+	struct prog_entry *prog;
+	int i;
+
+	prog = rcu_access_pointer(filter->prog);
+	if (!prog)
+		return;
+
+	for (i = 0; prog[i].pred; i++)
+		kfree(prog[i].pred);
+	kfree(prog);
+}
+
+static void filter_disable(struct trace_event_file *file)
+{
+	unsigned long old_flags = file->flags;
+
+	file->flags &= ~EVENT_FILE_FL_FILTERED;
+
+	if (old_flags != file->flags)
+		trace_buffered_event_disable();
+}
+
+static void __free_filter(struct event_filter *filter)
+{
+	if (!filter)
+		return;
+
+	free_prog(filter);
+	kfree(filter->filter_string);
+	kfree(filter);
+}
+
+void free_event_filter(struct event_filter *filter)
+{
+	__free_filter(filter);
+}
+
+static inline void __remove_filter(struct trace_event_file *file)
+{
+	filter_disable(file);
+	remove_filter_string(file->filter);
+}
+
+static void filter_free_subsystem_preds(struct trace_subsystem_dir *dir,
+					struct trace_array *tr)
+{
+	struct trace_event_file *file;
+
+	list_for_each_entry(file, &tr->events, list) {
+		if (file->system != dir)
+			continue;
+		__remove_filter(file);
+	}
+}
+
+static inline void __free_subsystem_filter(struct trace_event_file *file)
+{
+	__free_filter(file->filter);
+	file->filter = NULL;
+}
+
+static void filter_free_subsystem_filters(struct trace_subsystem_dir *dir,
+					  struct trace_array *tr)
+{
+	struct trace_event_file *file;
+
+	list_for_each_entry(file, &tr->events, list) {
+		if (file->system != dir)
+			continue;
+		__free_subsystem_filter(file);
+	}
+}
+
+int filter_assign_type(const char *type)
+{
+	if (strstr(type, "__data_loc") && strstr(type, "char"))
+		return FILTER_DYN_STRING;
+
+	if (strstr(type, "__rel_loc") && strstr(type, "char"))
+		return FILTER_RDYN_STRING;
+
+	if (strchr(type, '[') && strstr(type, "char"))
+		return FILTER_STATIC_STRING;
+
+	if (strcmp(type, "char *") == 0 || strcmp(type, "const char *") == 0)
+		return FILTER_PTR_STRING;
+
+	return FILTER_OTHER;
+}
+
+static enum filter_pred_fn select_comparison_fn(enum filter_op_ids op,
+						int field_size, int field_is_signed)
+{
+	enum filter_pred_fn fn = FILTER_PRED_FN_NOP;
+	int pred_func_index = -1;
+
+	switch (op) {
+	case OP_EQ:
+	case OP_NE:
+		break;
+	default:
+		if (WARN_ON_ONCE(op < PRED_FUNC_START))
+			return fn;
+		pred_func_index = op - PRED_FUNC_START;
+		if (WARN_ON_ONCE(pred_func_index > PRED_FUNC_MAX))
+			return fn;
+	}
+
+	switch (field_size) {
+	case 8:
+		if (pred_func_index < 0)
+			fn = FILTER_PRED_FN_64;
+		else if (field_is_signed)
+			fn = FILTER_PRED_FN_S64;
+		else
+			fn = FILTER_PRED_FN_U64;
+		break;
+	case 4:
+		if (pred_func_index < 0)
+			fn = FILTER_PRED_FN_32;
+		else if (field_is_signed)
+			fn = FILTER_PRED_FN_S32;
+		else
+			fn = FILTER_PRED_FN_U32;
+		break;
+	case 2:
+		if (pred_func_index < 0)
+			fn = FILTER_PRED_FN_16;
+		else if (field_is_signed)
+			fn = FILTER_PRED_FN_S16;
+		else
+			fn = FILTER_PRED_FN_U16;
+		break;
+	case 1:
+		if (pred_func_index < 0)
+			fn = FILTER_PRED_FN_8;
+		else if (field_is_signed)
+			fn = FILTER_PRED_FN_S8;
+		else
+			fn = FILTER_PRED_FN_U8;
+		break;
+	}
+
+	return fn;
+}
+
+
+static int filter_pred_fn_call(struct filter_pred *pred, void *event)
+{
+	switch (pred->fn_num) {
+	case FILTER_PRED_FN_64:
+		return filter_pred_64(pred, event);
+	case FILTER_PRED_FN_S64:
+		return filter_pred_s64(pred, event);
+	case FILTER_PRED_FN_U64:
+		return filter_pred_u64(pred, event);
+	case FILTER_PRED_FN_32:
+		return filter_pred_32(pred, event);
+	case FILTER_PRED_FN_S32:
+		return filter_pred_s32(pred, event);
+	case FILTER_PRED_FN_U32:
+		return filter_pred_u32(pred, event);
+	case FILTER_PRED_FN_16:
+		return filter_pred_16(pred, event);
+	case FILTER_PRED_FN_S16:
+		return filter_pred_s16(pred, event);
+	case FILTER_PRED_FN_U16:
+		return filter_pred_u16(pred, event);
+	case FILTER_PRED_FN_8:
+		return filter_pred_8(pred, event);
+	case FILTER_PRED_FN_S8:
+		return filter_pred_s8(pred, event);
+	case FILTER_PRED_FN_U8:
+		return filter_pred_u8(pred, event);
+	case FILTER_PRED_FN_COMM:
+		return filter_pred_comm(pred, event);
+	case FILTER_PRED_FN_STRING:
+		return filter_pred_string(pred, event);
+	case FILTER_PRED_FN_STRLOC:
+		return filter_pred_strloc(pred, event);
+	case FILTER_PRED_FN_STRRELLOC:
+		return filter_pred_strrelloc(pred, event);
+	case FILTER_PRED_FN_PCHAR_USER:
+		return filter_pred_pchar_user(pred, event);
+	case FILTER_PRED_FN_PCHAR:
+		return filter_pred_pchar(pred, event);
+	case FILTER_PRED_FN_CPU:
+		return filter_pred_cpu(pred, event);
+	case FILTER_PRED_TEST_VISITED:
+		return test_pred_visited_fn(pred, event);
+	default:
+		return 0;
+	}
+}
+
+/* Called when a predicate is encountered by predicate_parse() */
+static int parse_pred(const char *str, void *data,
+		      int pos, struct filter_parse_error *pe,
+		      struct filter_pred **pred_ptr)
+{
+	struct trace_event_call *call = data;
+	struct ftrace_event_field *field;
+	struct filter_pred *pred = NULL;
+	char num_buf[24];	/* Big enough to hold an address */
+	char *field_name;
+	bool ustring = false;
+	char q;
+	u64 val;
+	int len;
+	int ret;
+	int op;
+	int s;
+	int i = 0;
+
+	/* First find the field to associate to */
+	while (isspace(str[i]))
+		i++;
+	s = i;
+
+	while (isalnum(str[i]) || str[i] == '_')
+		i++;
+
+	len = i - s;
+
+	if (!len)
+		return -1;
+
+	field_name = kmemdup_nul(str + s, len, GFP_KERNEL);
+	if (!field_name)
+		return -ENOMEM;
+
+	/* Make sure that the field exists */
+
+	field = trace_find_event_field(call, field_name);
+	kfree(field_name);
+	if (!field) {
+		parse_error(pe, FILT_ERR_FIELD_NOT_FOUND, pos + i);
+		return -EINVAL;
+	}
+
+	/* See if the field is a user space string */
+	if ((len = str_has_prefix(str + i, ".ustring"))) {
+		ustring = true;
+		i += len;
+	}
+
+	while (isspace(str[i]))
+		i++;
+
+	/* Make sure this op is supported */
+	for (op = 0; ops[op]; op++) {
+		/* This is why '<=' must come before '<' in ops[] */
+		if (strncmp(str + i, ops[op], strlen(ops[op])) == 0)
+			break;
+	}
+
+	if (!ops[op]) {
+		parse_error(pe, FILT_ERR_INVALID_OP, pos + i);
+		goto err_free;
+	}
+
+	i += strlen(ops[op]);
+
+	while (isspace(str[i]))
+		i++;
+
+	s = i;
+
+	pred = kzalloc(sizeof(*pred), GFP_KERNEL);
+	if (!pred)
+		return -ENOMEM;
+
+	pred->field = field;
+	pred->offset = field->offset;
+	pred->op = op;
+
+	if (ftrace_event_is_function(call)) {
+		/*
+		 * Perf does things different with function events.
+		 * It only allows an "ip" field, and expects a string.
+		 * But the string does not need to be surrounded by quotes.
+		 * If it is a string, the assigned function as a nop,
+		 * (perf doesn't use it) and grab everything.
+		 */
+		if (strcmp(field->name, "ip") != 0) {
+			parse_error(pe, FILT_ERR_IP_FIELD_ONLY, pos + i);
+			goto err_free;
+		}
+		pred->fn_num = FILTER_PRED_FN_NOP;
+
+		/*
+		 * Quotes are not required, but if they exist then we need
+		 * to read them till we hit a matching one.
+		 */
+		if (str[i] == '\'' || str[i] == '"')
+			q = str[i];
+		else
+			q = 0;
+
+		for (i++; str[i]; i++) {
+			if (q && str[i] == q)
+				break;
+			if (!q && (str[i] == ')' || str[i] == '&' ||
+				   str[i] == '|'))
+				break;
+		}
+		/* Skip quotes */
+		if (q)
+			s++;
+		len = i - s;
+		if (len >= MAX_FILTER_STR_VAL) {
+			parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
+			goto err_free;
+		}
+
+		pred->regex.len = len;
+		strncpy(pred->regex.pattern, str + s, len);
+		pred->regex.pattern[len] = 0;
+
+	/* This is either a string, or an integer */
+	} else if (str[i] == '\'' || str[i] == '"') {
+		char q = str[i];
+
+		/* Make sure the op is OK for strings */
+		switch (op) {
+		case OP_NE:
+			pred->not = 1;
+			fallthrough;
+		case OP_GLOB:
+		case OP_EQ:
+			break;
+		default:
+			parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i);
+			goto err_free;
+		}
+
+		/* Make sure the field is OK for strings */
+		if (!is_string_field(field)) {
+			parse_error(pe, FILT_ERR_EXPECT_DIGIT, pos + i);
+			goto err_free;
+		}
+
+		for (i++; str[i]; i++) {
+			if (str[i] == q)
+				break;
+		}
+		if (!str[i]) {
+			parse_error(pe, FILT_ERR_MISSING_QUOTE, pos + i);
+			goto err_free;
+		}
+
+		/* Skip quotes */
+		s++;
+		len = i - s;
+		if (len >= MAX_FILTER_STR_VAL) {
+			parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
+			goto err_free;
+		}
+
+		pred->regex.len = len;
+		strncpy(pred->regex.pattern, str + s, len);
+		pred->regex.pattern[len] = 0;
+
+		filter_build_regex(pred);
+
+		if (field->filter_type == FILTER_COMM) {
+			pred->fn_num = FILTER_PRED_FN_COMM;
+
+		} else if (field->filter_type == FILTER_STATIC_STRING) {
+			pred->fn_num = FILTER_PRED_FN_STRING;
+			pred->regex.field_len = field->size;
+
+		} else if (field->filter_type == FILTER_DYN_STRING) {
+			pred->fn_num = FILTER_PRED_FN_STRLOC;
+		} else if (field->filter_type == FILTER_RDYN_STRING)
+			pred->fn_num = FILTER_PRED_FN_STRRELLOC;
+		else {
+
+			if (!ustring_per_cpu) {
+				/* Once allocated, keep it around for good */
+				ustring_per_cpu = alloc_percpu(struct ustring_buffer);
+				if (!ustring_per_cpu)
+					goto err_mem;
+			}
+
+			if (ustring)
+				pred->fn_num = FILTER_PRED_FN_PCHAR_USER;
+			else
+				pred->fn_num = FILTER_PRED_FN_PCHAR;
+		}
+		/* go past the last quote */
+		i++;
+
+	} else if (isdigit(str[i]) || str[i] == '-') {
+
+		/* Make sure the field is not a string */
+		if (is_string_field(field)) {
+			parse_error(pe, FILT_ERR_EXPECT_STRING, pos + i);
+			goto err_free;
+		}
+
+		if (op == OP_GLOB) {
+			parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i);
+			goto err_free;
+		}
+
+		if (str[i] == '-')
+			i++;
+
+		/* We allow 0xDEADBEEF */
+		while (isalnum(str[i]))
+			i++;
+
+		len = i - s;
+		/* 0xfeedfacedeadbeef is 18 chars max */
+		if (len >= sizeof(num_buf)) {
+			parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
+			goto err_free;
+		}
+
+		strncpy(num_buf, str + s, len);
+		num_buf[len] = 0;
+
+		/* Make sure it is a value */
+		if (field->is_signed)
+			ret = kstrtoll(num_buf, 0, &val);
+		else
+			ret = kstrtoull(num_buf, 0, &val);
+		if (ret) {
+			parse_error(pe, FILT_ERR_ILLEGAL_INTVAL, pos + s);
+			goto err_free;
+		}
+
+		pred->val = val;
+
+		if (field->filter_type == FILTER_CPU)
+			pred->fn_num = FILTER_PRED_FN_CPU;
+		else {
+			pred->fn_num = select_comparison_fn(pred->op, field->size,
+							    field->is_signed);
+			if (pred->op == OP_NE)
+				pred->not = 1;
+		}
+
+	} else {
+		parse_error(pe, FILT_ERR_INVALID_VALUE, pos + i);
+		goto err_free;
+	}
+
+	*pred_ptr = pred;
+	return i;
+
+err_free:
+	kfree(pred);
+	return -EINVAL;
+err_mem:
+	kfree(pred);
+	return -ENOMEM;
+}
+
+enum {
+	TOO_MANY_CLOSE		= -1,
+	TOO_MANY_OPEN		= -2,
+	MISSING_QUOTE		= -3,
+};
+
+/*
+ * Read the filter string once to calculate the number of predicates
+ * as well as how deep the parentheses go.
+ *
+ * Returns:
+ *   0 - everything is fine (err is undefined)
+ *  -1 - too many ')'
+ *  -2 - too many '('
+ *  -3 - No matching quote
+ */
+static int calc_stack(const char *str, int *parens, int *preds, int *err)
+{
+	bool is_pred = false;
+	int nr_preds = 0;
+	int open = 1; /* Count the expression as "(E)" */
+	int last_quote = 0;
+	int max_open = 1;
+	int quote = 0;
+	int i;
+
+	*err = 0;
+
+	for (i = 0; str[i]; i++) {
+		if (isspace(str[i]))
+			continue;
+		if (quote) {
+			if (str[i] == quote)
+			       quote = 0;
+			continue;
+		}
+
+		switch (str[i]) {
+		case '\'':
+		case '"':
+			quote = str[i];
+			last_quote = i;
+			break;
+		case '|':
+		case '&':
+			if (str[i+1] != str[i])
+				break;
+			is_pred = false;
+			continue;
+		case '(':
+			is_pred = false;
+			open++;
+			if (open > max_open)
+				max_open = open;
+			continue;
+		case ')':
+			is_pred = false;
+			if (open == 1) {
+				*err = i;
+				return TOO_MANY_CLOSE;
+			}
+			open--;
+			continue;
+		}
+		if (!is_pred) {
+			nr_preds++;
+			is_pred = true;
+		}
+	}
+
+	if (quote) {
+		*err = last_quote;
+		return MISSING_QUOTE;
+	}
+
+	if (open != 1) {
+		int level = open;
+
+		/* find the bad open */
+		for (i--; i; i--) {
+			if (quote) {
+				if (str[i] == quote)
+					quote = 0;
+				continue;
+			}
+			switch (str[i]) {
+			case '(':
+				if (level == open) {
+					*err = i;
+					return TOO_MANY_OPEN;
+				}
+				level--;
+				break;
+			case ')':
+				level++;
+				break;
+			case '\'':
+			case '"':
+				quote = str[i];
+				break;
+			}
+		}
+		/* First character is the '(' with missing ')' */
+		*err = 0;
+		return TOO_MANY_OPEN;
+	}
+
+	/* Set the size of the required stacks */
+	*parens = max_open;
+	*preds = nr_preds;
+	return 0;
+}
+
+static int process_preds(struct trace_event_call *call,
+			 const char *filter_string,
+			 struct event_filter *filter,
+			 struct filter_parse_error *pe)
+{
+	struct prog_entry *prog;
+	int nr_parens;
+	int nr_preds;
+	int index;
+	int ret;
+
+	ret = calc_stack(filter_string, &nr_parens, &nr_preds, &index);
+	if (ret < 0) {
+		switch (ret) {
+		case MISSING_QUOTE:
+			parse_error(pe, FILT_ERR_MISSING_QUOTE, index);
+			break;
+		case TOO_MANY_OPEN:
+			parse_error(pe, FILT_ERR_TOO_MANY_OPEN, index);
+			break;
+		default:
+			parse_error(pe, FILT_ERR_TOO_MANY_CLOSE, index);
+		}
+		return ret;
+	}
+
+	if (!nr_preds)
+		return -EINVAL;
+
+	prog = predicate_parse(filter_string, nr_parens, nr_preds,
+			       parse_pred, call, pe);
+	if (IS_ERR(prog))
+		return PTR_ERR(prog);
+
+	rcu_assign_pointer(filter->prog, prog);
+	return 0;
+}
+
+static inline void event_set_filtered_flag(struct trace_event_file *file)
+{
+	unsigned long old_flags = file->flags;
+
+	file->flags |= EVENT_FILE_FL_FILTERED;
+
+	if (old_flags != file->flags)
+		trace_buffered_event_enable();
+}
+
+static inline void event_set_filter(struct trace_event_file *file,
+				    struct event_filter *filter)
+{
+	rcu_assign_pointer(file->filter, filter);
+}
+
+static inline void event_clear_filter(struct trace_event_file *file)
+{
+	RCU_INIT_POINTER(file->filter, NULL);
+}
+
+struct filter_list {
+	struct list_head	list;
+	struct event_filter	*filter;
+};
+
+static int process_system_preds(struct trace_subsystem_dir *dir,
+				struct trace_array *tr,
+				struct filter_parse_error *pe,
+				char *filter_string)
+{
+	struct trace_event_file *file;
+	struct filter_list *filter_item;
+	struct event_filter *filter = NULL;
+	struct filter_list *tmp;
+	LIST_HEAD(filter_list);
+	bool fail = true;
+	int err;
+
+	list_for_each_entry(file, &tr->events, list) {
+
+		if (file->system != dir)
+			continue;
+
+		filter = kzalloc(sizeof(*filter), GFP_KERNEL);
+		if (!filter)
+			goto fail_mem;
+
+		filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
+		if (!filter->filter_string)
+			goto fail_mem;
+
+		err = process_preds(file->event_call, filter_string, filter, pe);
+		if (err) {
+			filter_disable(file);
+			parse_error(pe, FILT_ERR_BAD_SUBSYS_FILTER, 0);
+			append_filter_err(tr, pe, filter);
+		} else
+			event_set_filtered_flag(file);
+
+
+		filter_item = kzalloc(sizeof(*filter_item), GFP_KERNEL);
+		if (!filter_item)
+			goto fail_mem;
+
+		list_add_tail(&filter_item->list, &filter_list);
+		/*
+		 * Regardless of if this returned an error, we still
+		 * replace the filter for the call.
+		 */
+		filter_item->filter = event_filter(file);
+		event_set_filter(file, filter);
+		filter = NULL;
+
+		fail = false;
+	}
+
+	if (fail)
+		goto fail;
+
+	/*
+	 * The calls can still be using the old filters.
+	 * Do a synchronize_rcu() and to ensure all calls are
+	 * done with them before we free them.
+	 */
+	tracepoint_synchronize_unregister();
+	list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
+		__free_filter(filter_item->filter);
+		list_del(&filter_item->list);
+		kfree(filter_item);
+	}
+	return 0;
+ fail:
+	/* No call succeeded */
+	list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
+		list_del(&filter_item->list);
+		kfree(filter_item);
+	}
+	parse_error(pe, FILT_ERR_BAD_SUBSYS_FILTER, 0);
+	return -EINVAL;
+ fail_mem:
+	__free_filter(filter);
+	/* If any call succeeded, we still need to sync */
+	if (!fail)
+		tracepoint_synchronize_unregister();
+	list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
+		__free_filter(filter_item->filter);
+		list_del(&filter_item->list);
+		kfree(filter_item);
+	}
+	return -ENOMEM;
+}
+
+static int create_filter_start(char *filter_string, bool set_str,
+			       struct filter_parse_error **pse,
+			       struct event_filter **filterp)
+{
+	struct event_filter *filter;
+	struct filter_parse_error *pe = NULL;
+	int err = 0;
+
+	if (WARN_ON_ONCE(*pse || *filterp))
+		return -EINVAL;
+
+	filter = kzalloc(sizeof(*filter), GFP_KERNEL);
+	if (filter && set_str) {
+		filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
+		if (!filter->filter_string)
+			err = -ENOMEM;
+	}
+
+	pe = kzalloc(sizeof(*pe), GFP_KERNEL);
+
+	if (!filter || !pe || err) {
+		kfree(pe);
+		__free_filter(filter);
+		return -ENOMEM;
+	}
+
+	/* we're committed to creating a new filter */
+	*filterp = filter;
+	*pse = pe;
+
+	return 0;
+}
+
+static void create_filter_finish(struct filter_parse_error *pe)
+{
+	kfree(pe);
+}
+
+/**
+ * create_filter - create a filter for a trace_event_call
+ * @tr: the trace array associated with these events
+ * @call: trace_event_call to create a filter for
+ * @filter_string: filter string
+ * @set_str: remember @filter_str and enable detailed error in filter
+ * @filterp: out param for created filter (always updated on return)
+ *           Must be a pointer that references a NULL pointer.
+ *
+ * Creates a filter for @call with @filter_str.  If @set_str is %true,
+ * @filter_str is copied and recorded in the new filter.
+ *
+ * On success, returns 0 and *@filterp points to the new filter.  On
+ * failure, returns -errno and *@filterp may point to %NULL or to a new
+ * filter.  In the latter case, the returned filter contains error
+ * information if @set_str is %true and the caller is responsible for
+ * freeing it.
+ */
+static int create_filter(struct trace_array *tr,
+			 struct trace_event_call *call,
+			 char *filter_string, bool set_str,
+			 struct event_filter **filterp)
+{
+	struct filter_parse_error *pe = NULL;
+	int err;
+
+	/* filterp must point to NULL */
+	if (WARN_ON(*filterp))
+		*filterp = NULL;
+
+	err = create_filter_start(filter_string, set_str, &pe, filterp);
+	if (err)
+		return err;
+
+	err = process_preds(call, filter_string, *filterp, pe);
+	if (err && set_str)
+		append_filter_err(tr, pe, *filterp);
+	create_filter_finish(pe);
+
+	return err;
+}
+
+int create_event_filter(struct trace_array *tr,
+			struct trace_event_call *call,
+			char *filter_str, bool set_str,
+			struct event_filter **filterp)
+{
+	return create_filter(tr, call, filter_str, set_str, filterp);
+}
+
+/**
+ * create_system_filter - create a filter for an event subsystem
+ * @dir: the descriptor for the subsystem directory
+ * @filter_str: filter string
+ * @filterp: out param for created filter (always updated on return)
+ *
+ * Identical to create_filter() except that it creates a subsystem filter
+ * and always remembers @filter_str.
+ */
+static int create_system_filter(struct trace_subsystem_dir *dir,
+				char *filter_str, struct event_filter **filterp)
+{
+	struct filter_parse_error *pe = NULL;
+	int err;
+
+	err = create_filter_start(filter_str, true, &pe, filterp);
+	if (!err) {
+		err = process_system_preds(dir, dir->tr, pe, filter_str);
+		if (!err) {
+			/* System filters just show a default message */
+			kfree((*filterp)->filter_string);
+			(*filterp)->filter_string = NULL;
+		} else {
+			append_filter_err(dir->tr, pe, *filterp);
+		}
+	}
+	create_filter_finish(pe);
+
+	return err;
+}
+
+/* caller must hold event_mutex */
+int apply_event_filter(struct trace_event_file *file, char *filter_string)
+{
+	struct trace_event_call *call = file->event_call;
+	struct event_filter *filter = NULL;
+	int err;
+
+	if (file->flags & EVENT_FILE_FL_FREED)
+		return -ENODEV;
+
+	if (!strcmp(strstrip(filter_string), "0")) {
+		filter_disable(file);
+		filter = event_filter(file);
+
+		if (!filter)
+			return 0;
+
+		event_clear_filter(file);
+
+		/* Make sure the filter is not being used */
+		tracepoint_synchronize_unregister();
+		__free_filter(filter);
+
+		return 0;
+	}
+
+	err = create_filter(file->tr, call, filter_string, true, &filter);
+
+	/*
+	 * Always swap the call filter with the new filter
+	 * even if there was an error. If there was an error
+	 * in the filter, we disable the filter and show the error
+	 * string
+	 */
+	if (filter) {
+		struct event_filter *tmp;
+
+		tmp = event_filter(file);
+		if (!err)
+			event_set_filtered_flag(file);
+		else
+			filter_disable(file);
+
+		event_set_filter(file, filter);
+
+		if (tmp) {
+			/* Make sure the call is done with the filter */
+			tracepoint_synchronize_unregister();
+			__free_filter(tmp);
+		}
+	}
+
+	return err;
+}
+
+int apply_subsystem_event_filter(struct trace_subsystem_dir *dir,
+				 char *filter_string)
+{
+	struct event_subsystem *system = dir->subsystem;
+	struct trace_array *tr = dir->tr;
+	struct event_filter *filter = NULL;
+	int err = 0;
+
+	mutex_lock(&event_mutex);
+
+	/* Make sure the system still has events */
+	if (!dir->nr_events) {
+		err = -ENODEV;
+		goto out_unlock;
+	}
+
+	if (!strcmp(strstrip(filter_string), "0")) {
+		filter_free_subsystem_preds(dir, tr);
+		remove_filter_string(system->filter);
+		filter = system->filter;
+		system->filter = NULL;
+		/* Ensure all filters are no longer used */
+		tracepoint_synchronize_unregister();
+		filter_free_subsystem_filters(dir, tr);
+		__free_filter(filter);
+		goto out_unlock;
+	}
+
+	err = create_system_filter(dir, filter_string, &filter);
+	if (filter) {
+		/*
+		 * No event actually uses the system filter
+		 * we can free it without synchronize_rcu().
+		 */
+		__free_filter(system->filter);
+		system->filter = filter;
+	}
+out_unlock:
+	mutex_unlock(&event_mutex);
+
+	return err;
+}
+
+#ifdef CONFIG_PERF_EVENTS
+
+void ftrace_profile_free_filter(struct perf_event *event)
+{
+	struct event_filter *filter = event->filter;
+
+	event->filter = NULL;
+	__free_filter(filter);
+}
+
+struct function_filter_data {
+	struct ftrace_ops *ops;
+	int first_filter;
+	int first_notrace;
+};
+
+#ifdef CONFIG_FUNCTION_TRACER
+static char **
+ftrace_function_filter_re(char *buf, int len, int *count)
+{
+	char *str, **re;
+
+	str = kstrndup(buf, len, GFP_KERNEL);
+	if (!str)
+		return NULL;
+
+	/*
+	 * The argv_split function takes white space
+	 * as a separator, so convert ',' into spaces.
+	 */
+	strreplace(str, ',', ' ');
+
+	re = argv_split(GFP_KERNEL, str, count);
+	kfree(str);
+	return re;
+}
+
+static int ftrace_function_set_regexp(struct ftrace_ops *ops, int filter,
+				      int reset, char *re, int len)
+{
+	int ret;
+
+	if (filter)
+		ret = ftrace_set_filter(ops, re, len, reset);
+	else
+		ret = ftrace_set_notrace(ops, re, len, reset);
+
+	return ret;
+}
+
+static int __ftrace_function_set_filter(int filter, char *buf, int len,
+					struct function_filter_data *data)
+{
+	int i, re_cnt, ret = -EINVAL;
+	int *reset;
+	char **re;
+
+	reset = filter ? &data->first_filter : &data->first_notrace;
+
+	/*
+	 * The 'ip' field could have multiple filters set, separated
+	 * either by space or comma. We first cut the filter and apply
+	 * all pieces separately.
+	 */
+	re = ftrace_function_filter_re(buf, len, &re_cnt);
+	if (!re)
+		return -EINVAL;
+
+	for (i = 0; i < re_cnt; i++) {
+		ret = ftrace_function_set_regexp(data->ops, filter, *reset,
+						 re[i], strlen(re[i]));
+		if (ret)
+			break;
+
+		if (*reset)
+			*reset = 0;
+	}
+
+	argv_free(re);
+	return ret;
+}
+
+static int ftrace_function_check_pred(struct filter_pred *pred)
+{
+	struct ftrace_event_field *field = pred->field;
+
+	/*
+	 * Check the predicate for function trace, verify:
+	 *  - only '==' and '!=' is used
+	 *  - the 'ip' field is used
+	 */
+	if ((pred->op != OP_EQ) && (pred->op != OP_NE))
+		return -EINVAL;
+
+	if (strcmp(field->name, "ip"))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int ftrace_function_set_filter_pred(struct filter_pred *pred,
+					   struct function_filter_data *data)
+{
+	int ret;
+
+	/* Checking the node is valid for function trace. */
+	ret = ftrace_function_check_pred(pred);
+	if (ret)
+		return ret;
+
+	return __ftrace_function_set_filter(pred->op == OP_EQ,
+					    pred->regex.pattern,
+					    pred->regex.len,
+					    data);
+}
+
+static bool is_or(struct prog_entry *prog, int i)
+{
+	int target;
+
+	/*
+	 * Only "||" is allowed for function events, thus,
+	 * all true branches should jump to true, and any
+	 * false branch should jump to false.
+	 */
+	target = prog[i].target + 1;
+	/* True and false have NULL preds (all prog entries should jump to one */
+	if (prog[target].pred)
+		return false;
+
+	/* prog[target].target is 1 for TRUE, 0 for FALSE */
+	return prog[i].when_to_branch == prog[target].target;
+}
+
+static int ftrace_function_set_filter(struct perf_event *event,
+				      struct event_filter *filter)
+{
+	struct prog_entry *prog = rcu_dereference_protected(filter->prog,
+						lockdep_is_held(&event_mutex));
+	struct function_filter_data data = {
+		.first_filter  = 1,
+		.first_notrace = 1,
+		.ops           = &event->ftrace_ops,
+	};
+	int i;
+
+	for (i = 0; prog[i].pred; i++) {
+		struct filter_pred *pred = prog[i].pred;
+
+		if (!is_or(prog, i))
+			return -EINVAL;
+
+		if (ftrace_function_set_filter_pred(pred, &data) < 0)
+			return -EINVAL;
+	}
+	return 0;
+}
+#else
+static int ftrace_function_set_filter(struct perf_event *event,
+				      struct event_filter *filter)
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_FUNCTION_TRACER */
+
+int ftrace_profile_set_filter(struct perf_event *event, int event_id,
+			      char *filter_str)
+{
+	int err;
+	struct event_filter *filter = NULL;
+	struct trace_event_call *call;
+
+	mutex_lock(&event_mutex);
+
+	call = event->tp_event;
+
+	err = -EINVAL;
+	if (!call)
+		goto out_unlock;
+
+	err = -EEXIST;
+	if (event->filter)
+		goto out_unlock;
+
+	err = create_filter(NULL, call, filter_str, false, &filter);
+	if (err)
+		goto free_filter;
+
+	if (ftrace_event_is_function(call))
+		err = ftrace_function_set_filter(event, filter);
+	else
+		event->filter = filter;
+
+free_filter:
+	if (err || ftrace_event_is_function(call))
+		__free_filter(filter);
+
+out_unlock:
+	mutex_unlock(&event_mutex);
+
+	return err;
+}
+
+#endif /* CONFIG_PERF_EVENTS */
+
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+
+#define CREATE_TRACE_POINTS
+#include "trace_events_filter_test.h"
+
+#define DATA_REC(m, va, vb, vc, vd, ve, vf, vg, vh, nvisit) \
+{ \
+	.filter = FILTER, \
+	.rec    = { .a = va, .b = vb, .c = vc, .d = vd, \
+		    .e = ve, .f = vf, .g = vg, .h = vh }, \
+	.match  = m, \
+	.not_visited = nvisit, \
+}
+#define YES 1
+#define NO  0
+
+static struct test_filter_data_t {
+	char *filter;
+	struct trace_event_raw_ftrace_test_filter rec;
+	int match;
+	char *not_visited;
+} test_filter_data[] = {
+#define FILTER "a == 1 && b == 1 && c == 1 && d == 1 && " \
+	       "e == 1 && f == 1 && g == 1 && h == 1"
+	DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, ""),
+	DATA_REC(NO,  0, 1, 1, 1, 1, 1, 1, 1, "bcdefgh"),
+	DATA_REC(NO,  1, 1, 1, 1, 1, 1, 1, 0, ""),
+#undef FILTER
+#define FILTER "a == 1 || b == 1 || c == 1 || d == 1 || " \
+	       "e == 1 || f == 1 || g == 1 || h == 1"
+	DATA_REC(NO,  0, 0, 0, 0, 0, 0, 0, 0, ""),
+	DATA_REC(YES, 0, 0, 0, 0, 0, 0, 0, 1, ""),
+	DATA_REC(YES, 1, 0, 0, 0, 0, 0, 0, 0, "bcdefgh"),
+#undef FILTER
+#define FILTER "(a == 1 || b == 1) && (c == 1 || d == 1) && " \
+	       "(e == 1 || f == 1) && (g == 1 || h == 1)"
+	DATA_REC(NO,  0, 0, 1, 1, 1, 1, 1, 1, "dfh"),
+	DATA_REC(YES, 0, 1, 0, 1, 0, 1, 0, 1, ""),
+	DATA_REC(YES, 1, 0, 1, 0, 0, 1, 0, 1, "bd"),
+	DATA_REC(NO,  1, 0, 1, 0, 0, 1, 0, 0, "bd"),
+#undef FILTER
+#define FILTER "(a == 1 && b == 1) || (c == 1 && d == 1) || " \
+	       "(e == 1 && f == 1) || (g == 1 && h == 1)"
+	DATA_REC(YES, 1, 0, 1, 1, 1, 1, 1, 1, "efgh"),
+	DATA_REC(YES, 0, 0, 0, 0, 0, 0, 1, 1, ""),
+	DATA_REC(NO,  0, 0, 0, 0, 0, 0, 0, 1, ""),
+#undef FILTER
+#define FILTER "(a == 1 && b == 1) && (c == 1 && d == 1) && " \
+	       "(e == 1 && f == 1) || (g == 1 && h == 1)"
+	DATA_REC(YES, 1, 1, 1, 1, 1, 1, 0, 0, "gh"),
+	DATA_REC(NO,  0, 0, 0, 0, 0, 0, 0, 1, ""),
+	DATA_REC(YES, 1, 1, 1, 1, 1, 0, 1, 1, ""),
+#undef FILTER
+#define FILTER "((a == 1 || b == 1) || (c == 1 || d == 1) || " \
+	       "(e == 1 || f == 1)) && (g == 1 || h == 1)"
+	DATA_REC(YES, 1, 1, 1, 1, 1, 1, 0, 1, "bcdef"),
+	DATA_REC(NO,  0, 0, 0, 0, 0, 0, 0, 0, ""),
+	DATA_REC(YES, 1, 1, 1, 1, 1, 0, 1, 1, "h"),
+#undef FILTER
+#define FILTER "((((((((a == 1) && (b == 1)) || (c == 1)) && (d == 1)) || " \
+	       "(e == 1)) && (f == 1)) || (g == 1)) && (h == 1))"
+	DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, "ceg"),
+	DATA_REC(NO,  0, 1, 0, 1, 0, 1, 0, 1, ""),
+	DATA_REC(NO,  1, 0, 1, 0, 1, 0, 1, 0, ""),
+#undef FILTER
+#define FILTER "((((((((a == 1) || (b == 1)) && (c == 1)) || (d == 1)) && " \
+	       "(e == 1)) || (f == 1)) && (g == 1)) || (h == 1))"
+	DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, "bdfh"),
+	DATA_REC(YES, 0, 1, 0, 1, 0, 1, 0, 1, ""),
+	DATA_REC(YES, 1, 0, 1, 0, 1, 0, 1, 0, "bdfh"),
+};
+
+#undef DATA_REC
+#undef FILTER
+#undef YES
+#undef NO
+
+#define DATA_CNT ARRAY_SIZE(test_filter_data)
+
+static int test_pred_visited;
+
+static int test_pred_visited_fn(struct filter_pred *pred, void *event)
+{
+	struct ftrace_event_field *field = pred->field;
+
+	test_pred_visited = 1;
+	printk(KERN_INFO "\npred visited %s\n", field->name);
+	return 1;
+}
+
+static void update_pred_fn(struct event_filter *filter, char *fields)
+{
+	struct prog_entry *prog = rcu_dereference_protected(filter->prog,
+						lockdep_is_held(&event_mutex));
+	int i;
+
+	for (i = 0; prog[i].pred; i++) {
+		struct filter_pred *pred = prog[i].pred;
+		struct ftrace_event_field *field = pred->field;
+
+		WARN_ON_ONCE(pred->fn_num == FILTER_PRED_FN_NOP);
+
+		if (!field) {
+			WARN_ONCE(1, "all leafs should have field defined %d", i);
+			continue;
+		}
+
+		if (!strchr(fields, *field->name))
+			continue;
+
+		pred->fn_num = FILTER_PRED_TEST_VISITED;
+	}
+}
+
+static __init int ftrace_test_event_filter(void)
+{
+	int i;
+
+	printk(KERN_INFO "Testing ftrace filter: ");
+
+	for (i = 0; i < DATA_CNT; i++) {
+		struct event_filter *filter = NULL;
+		struct test_filter_data_t *d = &test_filter_data[i];
+		int err;
+
+		err = create_filter(NULL, &event_ftrace_test_filter,
+				    d->filter, false, &filter);
+		if (err) {
+			printk(KERN_INFO
+			       "Failed to get filter for '%s', err %d\n",
+			       d->filter, err);
+			__free_filter(filter);
+			break;
+		}
+
+		/* Needed to dereference filter->prog */
+		mutex_lock(&event_mutex);
+		/*
+		 * The preemption disabling is not really needed for self
+		 * tests, but the rcu dereference will complain without it.
+		 */
+		preempt_disable();
+		if (*d->not_visited)
+			update_pred_fn(filter, d->not_visited);
+
+		test_pred_visited = 0;
+		err = filter_match_preds(filter, &d->rec);
+		preempt_enable();
+
+		mutex_unlock(&event_mutex);
+
+		__free_filter(filter);
+
+		if (test_pred_visited) {
+			printk(KERN_INFO
+			       "Failed, unwanted pred visited for filter %s\n",
+			       d->filter);
+			break;
+		}
+
+		if (err != d->match) {
+			printk(KERN_INFO
+			       "Failed to match filter '%s', expected %d\n",
+			       d->filter, d->match);
+			break;
+		}
+	}
+
+	if (i == DATA_CNT)
+		printk(KERN_CONT "OK\n");
+
+	return 0;
+}
+
+late_initcall(ftrace_test_event_filter);
+
+#endif /* CONFIG_FTRACE_STARTUP_TEST */
diff --git a/kernel/trace/trace_events_filter_test.h b/kernel/trace/trace_events_filter_test.h
new file mode 100644
index 000000000..e651dfbd3
--- /dev/null
+++ b/kernel/trace/trace_events_filter_test.h
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM test
+
+#if !defined(_TRACE_TEST_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_TEST_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(ftrace_test_filter,
+
+	TP_PROTO(int a, int b, int c, int d, int e, int f, int g, int h),
+
+	TP_ARGS(a, b, c, d, e, f, g, h),
+
+	TP_STRUCT__entry(
+		__field(int, a)
+		__field(int, b)
+		__field(int, c)
+		__field(int, d)
+		__field(int, e)
+		__field(int, f)
+		__field(int, g)
+		__field(int, h)
+	),
+
+	TP_fast_assign(
+		__entry->a = a;
+		__entry->b = b;
+		__entry->c = c;
+		__entry->d = d;
+		__entry->e = e;
+		__entry->f = f;
+		__entry->g = g;
+		__entry->h = h;
+	),
+
+	TP_printk("a %d, b %d, c %d, d %d, e %d, f %d, g %d, h %d",
+		  __entry->a, __entry->b, __entry->c, __entry->d,
+		  __entry->e, __entry->f, __entry->g, __entry->h)
+);
+
+#endif /* _TRACE_TEST_H || TRACE_HEADER_MULTI_READ */
+
+#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE trace_events_filter_test
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
new file mode 100644
index 000000000..3b0da1bdd
--- /dev/null
+++ b/kernel/trace/trace_events_hist.c
@@ -0,0 +1,6757 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_events_hist - trace event hist triggers
+ *
+ * Copyright (C) 2015 Tom Zanussi <tom.zanussi@linux.intel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/security.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/stacktrace.h>
+#include <linux/rculist.h>
+#include <linux/tracefs.h>
+
+/* for gfp flag names */
+#include <linux/trace_events.h>
+#include <trace/events/mmflags.h>
+
+#include "tracing_map.h"
+#include "trace_synth.h"
+
+#define ERRORS								\
+	C(NONE,			"No error"),				\
+	C(DUPLICATE_VAR,	"Variable already defined"),		\
+	C(VAR_NOT_UNIQUE,	"Variable name not unique, need to use fully qualified name (subsys.event.var) for variable"), \
+	C(TOO_MANY_VARS,	"Too many variables defined"),		\
+	C(MALFORMED_ASSIGNMENT,	"Malformed assignment"),		\
+	C(NAMED_MISMATCH,	"Named hist trigger doesn't match existing named trigger (includes variables)"), \
+	C(TRIGGER_EEXIST,	"Hist trigger already exists"),		\
+	C(TRIGGER_ENOENT_CLEAR,	"Can't clear or continue a nonexistent hist trigger"), \
+	C(SET_CLOCK_FAIL,	"Couldn't set trace_clock"),		\
+	C(BAD_FIELD_MODIFIER,	"Invalid field modifier"),		\
+	C(TOO_MANY_SUBEXPR,	"Too many subexpressions (3 max)"),	\
+	C(TIMESTAMP_MISMATCH,	"Timestamp units in expression don't match"), \
+	C(TOO_MANY_FIELD_VARS,	"Too many field variables defined"),	\
+	C(EVENT_FILE_NOT_FOUND,	"Event file not found"),		\
+	C(HIST_NOT_FOUND,	"Matching event histogram not found"),	\
+	C(HIST_CREATE_FAIL,	"Couldn't create histogram for field"),	\
+	C(SYNTH_VAR_NOT_FOUND,	"Couldn't find synthetic variable"),	\
+	C(SYNTH_EVENT_NOT_FOUND,"Couldn't find synthetic event"),	\
+	C(SYNTH_TYPE_MISMATCH,	"Param type doesn't match synthetic event field type"), \
+	C(SYNTH_COUNT_MISMATCH,	"Param count doesn't match synthetic event field count"), \
+	C(FIELD_VAR_PARSE_FAIL,	"Couldn't parse field variable"),	\
+	C(VAR_CREATE_FIND_FAIL,	"Couldn't create or find variable"),	\
+	C(ONX_NOT_VAR,		"For onmax(x) or onchange(x), x must be a variable"), \
+	C(ONX_VAR_NOT_FOUND,	"Couldn't find onmax or onchange variable"), \
+	C(ONX_VAR_CREATE_FAIL,	"Couldn't create onmax or onchange variable"), \
+	C(FIELD_VAR_CREATE_FAIL,"Couldn't create field variable"),	\
+	C(TOO_MANY_PARAMS,	"Too many action params"),		\
+	C(PARAM_NOT_FOUND,	"Couldn't find param"),			\
+	C(INVALID_PARAM,	"Invalid action param"),		\
+	C(ACTION_NOT_FOUND,	"No action found"),			\
+	C(NO_SAVE_PARAMS,	"No params found for save()"),		\
+	C(TOO_MANY_SAVE_ACTIONS,"Can't have more than one save() action per hist"), \
+	C(ACTION_MISMATCH,	"Handler doesn't support action"),	\
+	C(NO_CLOSING_PAREN,	"No closing paren found"),		\
+	C(SUBSYS_NOT_FOUND,	"Missing subsystem"),			\
+	C(INVALID_SUBSYS_EVENT,	"Invalid subsystem or event name"),	\
+	C(INVALID_REF_KEY,	"Using variable references in keys not supported"), \
+	C(VAR_NOT_FOUND,	"Couldn't find variable"),		\
+	C(FIELD_NOT_FOUND,	"Couldn't find field"),			\
+	C(EMPTY_ASSIGNMENT,	"Empty assignment"),			\
+	C(INVALID_SORT_MODIFIER,"Invalid sort modifier"),		\
+	C(EMPTY_SORT_FIELD,	"Empty sort field"),			\
+	C(TOO_MANY_SORT_FIELDS,	"Too many sort fields (Max = 2)"),	\
+	C(INVALID_SORT_FIELD,	"Sort field must be a key or a val"),	\
+	C(INVALID_STR_OPERAND,	"String type can not be an operand in expression"), \
+	C(EXPECT_NUMBER,	"Expecting numeric literal"),		\
+	C(UNARY_MINUS_SUBEXPR,	"Unary minus not supported in sub-expressions"), \
+	C(DIVISION_BY_ZERO,	"Division by zero"),
+
+#undef C
+#define C(a, b)		HIST_ERR_##a
+
+enum { ERRORS };
+
+#undef C
+#define C(a, b)		b
+
+static const char *err_text[] = { ERRORS };
+
+struct hist_field;
+
+typedef u64 (*hist_field_fn_t) (struct hist_field *field,
+				struct tracing_map_elt *elt,
+				struct trace_buffer *buffer,
+				struct ring_buffer_event *rbe,
+				void *event);
+
+#define HIST_FIELD_OPERANDS_MAX	2
+#define HIST_FIELDS_MAX		(TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX)
+#define HIST_ACTIONS_MAX	8
+#define HIST_CONST_DIGITS_MAX	21
+#define HIST_DIV_SHIFT		20  /* For optimizing division by constants */
+
+enum field_op_id {
+	FIELD_OP_NONE,
+	FIELD_OP_PLUS,
+	FIELD_OP_MINUS,
+	FIELD_OP_UNARY_MINUS,
+	FIELD_OP_DIV,
+	FIELD_OP_MULT,
+};
+
+enum hist_field_fn {
+	HIST_FIELD_FN_NOP,
+	HIST_FIELD_FN_VAR_REF,
+	HIST_FIELD_FN_COUNTER,
+	HIST_FIELD_FN_CONST,
+	HIST_FIELD_FN_LOG2,
+	HIST_FIELD_FN_BUCKET,
+	HIST_FIELD_FN_TIMESTAMP,
+	HIST_FIELD_FN_CPU,
+	HIST_FIELD_FN_STRING,
+	HIST_FIELD_FN_DYNSTRING,
+	HIST_FIELD_FN_RELDYNSTRING,
+	HIST_FIELD_FN_PSTRING,
+	HIST_FIELD_FN_S64,
+	HIST_FIELD_FN_U64,
+	HIST_FIELD_FN_S32,
+	HIST_FIELD_FN_U32,
+	HIST_FIELD_FN_S16,
+	HIST_FIELD_FN_U16,
+	HIST_FIELD_FN_S8,
+	HIST_FIELD_FN_U8,
+	HIST_FIELD_FN_UMINUS,
+	HIST_FIELD_FN_MINUS,
+	HIST_FIELD_FN_PLUS,
+	HIST_FIELD_FN_DIV,
+	HIST_FIELD_FN_MULT,
+	HIST_FIELD_FN_DIV_POWER2,
+	HIST_FIELD_FN_DIV_NOT_POWER2,
+	HIST_FIELD_FN_DIV_MULT_SHIFT,
+	HIST_FIELD_FN_EXECNAME,
+};
+
+/*
+ * A hist_var (histogram variable) contains variable information for
+ * hist_fields having the HIST_FIELD_FL_VAR or HIST_FIELD_FL_VAR_REF
+ * flag set.  A hist_var has a variable name e.g. ts0, and is
+ * associated with a given histogram trigger, as specified by
+ * hist_data.  The hist_var idx is the unique index assigned to the
+ * variable by the hist trigger's tracing_map.  The idx is what is
+ * used to set a variable's value and, by a variable reference, to
+ * retrieve it.
+ */
+struct hist_var {
+	char				*name;
+	struct hist_trigger_data	*hist_data;
+	unsigned int			idx;
+};
+
+struct hist_field {
+	struct ftrace_event_field	*field;
+	unsigned long			flags;
+	unsigned long			buckets;
+	const char			*type;
+	struct hist_field		*operands[HIST_FIELD_OPERANDS_MAX];
+	struct hist_trigger_data	*hist_data;
+	enum hist_field_fn		fn_num;
+	unsigned int			ref;
+	unsigned int			size;
+	unsigned int			offset;
+	unsigned int                    is_signed;
+
+	/*
+	 * Variable fields contain variable-specific info in var.
+	 */
+	struct hist_var			var;
+	enum field_op_id		operator;
+	char				*system;
+	char				*event_name;
+
+	/*
+	 * The name field is used for EXPR and VAR_REF fields.  VAR
+	 * fields contain the variable name in var.name.
+	 */
+	char				*name;
+
+	/*
+	 * When a histogram trigger is hit, if it has any references
+	 * to variables, the values of those variables are collected
+	 * into a var_ref_vals array by resolve_var_refs().  The
+	 * current value of each variable is read from the tracing_map
+	 * using the hist field's hist_var.idx and entered into the
+	 * var_ref_idx entry i.e. var_ref_vals[var_ref_idx].
+	 */
+	unsigned int			var_ref_idx;
+	bool                            read_once;
+
+	unsigned int			var_str_idx;
+
+	/* Numeric literals are represented as u64 */
+	u64				constant;
+	/* Used to optimize division by constants */
+	u64				div_multiplier;
+};
+
+static u64 hist_fn_call(struct hist_field *hist_field,
+			struct tracing_map_elt *elt,
+			struct trace_buffer *buffer,
+			struct ring_buffer_event *rbe,
+			void *event);
+
+static u64 hist_field_const(struct hist_field *field,
+			   struct tracing_map_elt *elt,
+			   struct trace_buffer *buffer,
+			   struct ring_buffer_event *rbe,
+			   void *event)
+{
+	return field->constant;
+}
+
+static u64 hist_field_counter(struct hist_field *field,
+			      struct tracing_map_elt *elt,
+			      struct trace_buffer *buffer,
+			      struct ring_buffer_event *rbe,
+			      void *event)
+{
+	return 1;
+}
+
+static u64 hist_field_string(struct hist_field *hist_field,
+			     struct tracing_map_elt *elt,
+			     struct trace_buffer *buffer,
+			     struct ring_buffer_event *rbe,
+			     void *event)
+{
+	char *addr = (char *)(event + hist_field->field->offset);
+
+	return (u64)(unsigned long)addr;
+}
+
+static u64 hist_field_dynstring(struct hist_field *hist_field,
+				struct tracing_map_elt *elt,
+				struct trace_buffer *buffer,
+				struct ring_buffer_event *rbe,
+				void *event)
+{
+	u32 str_item = *(u32 *)(event + hist_field->field->offset);
+	int str_loc = str_item & 0xffff;
+	char *addr = (char *)(event + str_loc);
+
+	return (u64)(unsigned long)addr;
+}
+
+static u64 hist_field_reldynstring(struct hist_field *hist_field,
+				   struct tracing_map_elt *elt,
+				   struct trace_buffer *buffer,
+				   struct ring_buffer_event *rbe,
+				   void *event)
+{
+	u32 *item = event + hist_field->field->offset;
+	u32 str_item = *item;
+	int str_loc = str_item & 0xffff;
+	char *addr = (char *)&item[1] + str_loc;
+
+	return (u64)(unsigned long)addr;
+}
+
+static u64 hist_field_pstring(struct hist_field *hist_field,
+			      struct tracing_map_elt *elt,
+			      struct trace_buffer *buffer,
+			      struct ring_buffer_event *rbe,
+			      void *event)
+{
+	char **addr = (char **)(event + hist_field->field->offset);
+
+	return (u64)(unsigned long)*addr;
+}
+
+static u64 hist_field_log2(struct hist_field *hist_field,
+			   struct tracing_map_elt *elt,
+			   struct trace_buffer *buffer,
+			   struct ring_buffer_event *rbe,
+			   void *event)
+{
+	struct hist_field *operand = hist_field->operands[0];
+
+	u64 val = hist_fn_call(operand, elt, buffer, rbe, event);
+
+	return (u64) ilog2(roundup_pow_of_two(val));
+}
+
+static u64 hist_field_bucket(struct hist_field *hist_field,
+			     struct tracing_map_elt *elt,
+			     struct trace_buffer *buffer,
+			     struct ring_buffer_event *rbe,
+			     void *event)
+{
+	struct hist_field *operand = hist_field->operands[0];
+	unsigned long buckets = hist_field->buckets;
+
+	u64 val = hist_fn_call(operand, elt, buffer, rbe, event);
+
+	if (WARN_ON_ONCE(!buckets))
+		return val;
+
+	if (val >= LONG_MAX)
+		val = div64_ul(val, buckets);
+	else
+		val = (u64)((unsigned long)val / buckets);
+	return val * buckets;
+}
+
+static u64 hist_field_plus(struct hist_field *hist_field,
+			   struct tracing_map_elt *elt,
+			   struct trace_buffer *buffer,
+			   struct ring_buffer_event *rbe,
+			   void *event)
+{
+	struct hist_field *operand1 = hist_field->operands[0];
+	struct hist_field *operand2 = hist_field->operands[1];
+
+	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
+	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
+
+	return val1 + val2;
+}
+
+static u64 hist_field_minus(struct hist_field *hist_field,
+			    struct tracing_map_elt *elt,
+			    struct trace_buffer *buffer,
+			    struct ring_buffer_event *rbe,
+			    void *event)
+{
+	struct hist_field *operand1 = hist_field->operands[0];
+	struct hist_field *operand2 = hist_field->operands[1];
+
+	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
+	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
+
+	return val1 - val2;
+}
+
+static u64 hist_field_div(struct hist_field *hist_field,
+			   struct tracing_map_elt *elt,
+			   struct trace_buffer *buffer,
+			   struct ring_buffer_event *rbe,
+			   void *event)
+{
+	struct hist_field *operand1 = hist_field->operands[0];
+	struct hist_field *operand2 = hist_field->operands[1];
+
+	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
+	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
+
+	/* Return -1 for the undefined case */
+	if (!val2)
+		return -1;
+
+	/* Use shift if the divisor is a power of 2 */
+	if (!(val2 & (val2 - 1)))
+		return val1 >> __ffs64(val2);
+
+	return div64_u64(val1, val2);
+}
+
+static u64 div_by_power_of_two(struct hist_field *hist_field,
+				struct tracing_map_elt *elt,
+				struct trace_buffer *buffer,
+				struct ring_buffer_event *rbe,
+				void *event)
+{
+	struct hist_field *operand1 = hist_field->operands[0];
+	struct hist_field *operand2 = hist_field->operands[1];
+
+	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
+
+	return val1 >> __ffs64(operand2->constant);
+}
+
+static u64 div_by_not_power_of_two(struct hist_field *hist_field,
+				struct tracing_map_elt *elt,
+				struct trace_buffer *buffer,
+				struct ring_buffer_event *rbe,
+				void *event)
+{
+	struct hist_field *operand1 = hist_field->operands[0];
+	struct hist_field *operand2 = hist_field->operands[1];
+
+	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
+
+	return div64_u64(val1, operand2->constant);
+}
+
+static u64 div_by_mult_and_shift(struct hist_field *hist_field,
+				struct tracing_map_elt *elt,
+				struct trace_buffer *buffer,
+				struct ring_buffer_event *rbe,
+				void *event)
+{
+	struct hist_field *operand1 = hist_field->operands[0];
+	struct hist_field *operand2 = hist_field->operands[1];
+
+	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
+
+	/*
+	 * If the divisor is a constant, do a multiplication and shift instead.
+	 *
+	 * Choose Z = some power of 2. If Y <= Z, then:
+	 *     X / Y = (X * (Z / Y)) / Z
+	 *
+	 * (Z / Y) is a constant (mult) which is calculated at parse time, so:
+	 *     X / Y = (X * mult) / Z
+	 *
+	 * The division by Z can be replaced by a shift since Z is a power of 2:
+	 *     X / Y = (X * mult) >> HIST_DIV_SHIFT
+	 *
+	 * As long, as X < Z the results will not be off by more than 1.
+	 */
+	if (val1 < (1 << HIST_DIV_SHIFT)) {
+		u64 mult = operand2->div_multiplier;
+
+		return (val1 * mult + ((1 << HIST_DIV_SHIFT) - 1)) >> HIST_DIV_SHIFT;
+	}
+
+	return div64_u64(val1, operand2->constant);
+}
+
+static u64 hist_field_mult(struct hist_field *hist_field,
+			   struct tracing_map_elt *elt,
+			   struct trace_buffer *buffer,
+			   struct ring_buffer_event *rbe,
+			   void *event)
+{
+	struct hist_field *operand1 = hist_field->operands[0];
+	struct hist_field *operand2 = hist_field->operands[1];
+
+	u64 val1 = hist_fn_call(operand1, elt, buffer, rbe, event);
+	u64 val2 = hist_fn_call(operand2, elt, buffer, rbe, event);
+
+	return val1 * val2;
+}
+
+static u64 hist_field_unary_minus(struct hist_field *hist_field,
+				  struct tracing_map_elt *elt,
+				  struct trace_buffer *buffer,
+				  struct ring_buffer_event *rbe,
+				  void *event)
+{
+	struct hist_field *operand = hist_field->operands[0];
+
+	s64 sval = (s64)hist_fn_call(operand, elt, buffer, rbe, event);
+	u64 val = (u64)-sval;
+
+	return val;
+}
+
+#define DEFINE_HIST_FIELD_FN(type)					\
+	static u64 hist_field_##type(struct hist_field *hist_field,	\
+				     struct tracing_map_elt *elt,	\
+				     struct trace_buffer *buffer,	\
+				     struct ring_buffer_event *rbe,	\
+				     void *event)			\
+{									\
+	type *addr = (type *)(event + hist_field->field->offset);	\
+									\
+	return (u64)(unsigned long)*addr;				\
+}
+
+DEFINE_HIST_FIELD_FN(s64);
+DEFINE_HIST_FIELD_FN(u64);
+DEFINE_HIST_FIELD_FN(s32);
+DEFINE_HIST_FIELD_FN(u32);
+DEFINE_HIST_FIELD_FN(s16);
+DEFINE_HIST_FIELD_FN(u16);
+DEFINE_HIST_FIELD_FN(s8);
+DEFINE_HIST_FIELD_FN(u8);
+
+#define for_each_hist_field(i, hist_data)	\
+	for ((i) = 0; (i) < (hist_data)->n_fields; (i)++)
+
+#define for_each_hist_val_field(i, hist_data)	\
+	for ((i) = 0; (i) < (hist_data)->n_vals; (i)++)
+
+#define for_each_hist_key_field(i, hist_data)	\
+	for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)
+
+#define HITCOUNT_IDX		0
+#define HIST_KEY_SIZE_MAX	(MAX_FILTER_STR_VAL + HIST_STACKTRACE_SIZE)
+
+enum hist_field_flags {
+	HIST_FIELD_FL_HITCOUNT		= 1 << 0,
+	HIST_FIELD_FL_KEY		= 1 << 1,
+	HIST_FIELD_FL_STRING		= 1 << 2,
+	HIST_FIELD_FL_HEX		= 1 << 3,
+	HIST_FIELD_FL_SYM		= 1 << 4,
+	HIST_FIELD_FL_SYM_OFFSET	= 1 << 5,
+	HIST_FIELD_FL_EXECNAME		= 1 << 6,
+	HIST_FIELD_FL_SYSCALL		= 1 << 7,
+	HIST_FIELD_FL_STACKTRACE	= 1 << 8,
+	HIST_FIELD_FL_LOG2		= 1 << 9,
+	HIST_FIELD_FL_TIMESTAMP		= 1 << 10,
+	HIST_FIELD_FL_TIMESTAMP_USECS	= 1 << 11,
+	HIST_FIELD_FL_VAR		= 1 << 12,
+	HIST_FIELD_FL_EXPR		= 1 << 13,
+	HIST_FIELD_FL_VAR_REF		= 1 << 14,
+	HIST_FIELD_FL_CPU		= 1 << 15,
+	HIST_FIELD_FL_ALIAS		= 1 << 16,
+	HIST_FIELD_FL_BUCKET		= 1 << 17,
+	HIST_FIELD_FL_CONST		= 1 << 18,
+	HIST_FIELD_FL_PERCENT		= 1 << 19,
+	HIST_FIELD_FL_GRAPH		= 1 << 20,
+};
+
+struct var_defs {
+	unsigned int	n_vars;
+	char		*name[TRACING_MAP_VARS_MAX];
+	char		*expr[TRACING_MAP_VARS_MAX];
+};
+
+struct hist_trigger_attrs {
+	char		*keys_str;
+	char		*vals_str;
+	char		*sort_key_str;
+	char		*name;
+	char		*clock;
+	bool		pause;
+	bool		cont;
+	bool		clear;
+	bool		ts_in_usecs;
+	unsigned int	map_bits;
+
+	char		*assignment_str[TRACING_MAP_VARS_MAX];
+	unsigned int	n_assignments;
+
+	char		*action_str[HIST_ACTIONS_MAX];
+	unsigned int	n_actions;
+
+	struct var_defs	var_defs;
+};
+
+struct field_var {
+	struct hist_field	*var;
+	struct hist_field	*val;
+};
+
+struct field_var_hist {
+	struct hist_trigger_data	*hist_data;
+	char				*cmd;
+};
+
+struct hist_trigger_data {
+	struct hist_field               *fields[HIST_FIELDS_MAX];
+	unsigned int			n_vals;
+	unsigned int			n_keys;
+	unsigned int			n_fields;
+	unsigned int			n_vars;
+	unsigned int			n_var_str;
+	unsigned int			key_size;
+	struct tracing_map_sort_key	sort_keys[TRACING_MAP_SORT_KEYS_MAX];
+	unsigned int			n_sort_keys;
+	struct trace_event_file		*event_file;
+	struct hist_trigger_attrs	*attrs;
+	struct tracing_map		*map;
+	bool				enable_timestamps;
+	bool				remove;
+	struct hist_field               *var_refs[TRACING_MAP_VARS_MAX];
+	unsigned int			n_var_refs;
+
+	struct action_data		*actions[HIST_ACTIONS_MAX];
+	unsigned int			n_actions;
+
+	struct field_var		*field_vars[SYNTH_FIELDS_MAX];
+	unsigned int			n_field_vars;
+	unsigned int			n_field_var_str;
+	struct field_var_hist		*field_var_hists[SYNTH_FIELDS_MAX];
+	unsigned int			n_field_var_hists;
+
+	struct field_var		*save_vars[SYNTH_FIELDS_MAX];
+	unsigned int			n_save_vars;
+	unsigned int			n_save_var_str;
+};
+
+struct action_data;
+
+typedef void (*action_fn_t) (struct hist_trigger_data *hist_data,
+			     struct tracing_map_elt *elt,
+			     struct trace_buffer *buffer, void *rec,
+			     struct ring_buffer_event *rbe, void *key,
+			     struct action_data *data, u64 *var_ref_vals);
+
+typedef bool (*check_track_val_fn_t) (u64 track_val, u64 var_val);
+
+enum handler_id {
+	HANDLER_ONMATCH = 1,
+	HANDLER_ONMAX,
+	HANDLER_ONCHANGE,
+};
+
+enum action_id {
+	ACTION_SAVE = 1,
+	ACTION_TRACE,
+	ACTION_SNAPSHOT,
+};
+
+struct action_data {
+	enum handler_id		handler;
+	enum action_id		action;
+	char			*action_name;
+	action_fn_t		fn;
+
+	unsigned int		n_params;
+	char			*params[SYNTH_FIELDS_MAX];
+
+	/*
+	 * When a histogram trigger is hit, the values of any
+	 * references to variables, including variables being passed
+	 * as parameters to synthetic events, are collected into a
+	 * var_ref_vals array.  This var_ref_idx array is an array of
+	 * indices into the var_ref_vals array, one for each synthetic
+	 * event param, and is passed to the synthetic event
+	 * invocation.
+	 */
+	unsigned int		var_ref_idx[SYNTH_FIELDS_MAX];
+	struct synth_event	*synth_event;
+	bool			use_trace_keyword;
+	char			*synth_event_name;
+
+	union {
+		struct {
+			char			*event;
+			char			*event_system;
+		} match_data;
+
+		struct {
+			/*
+			 * var_str contains the $-unstripped variable
+			 * name referenced by var_ref, and used when
+			 * printing the action.  Because var_ref
+			 * creation is deferred to create_actions(),
+			 * we need a per-action way to save it until
+			 * then, thus var_str.
+			 */
+			char			*var_str;
+
+			/*
+			 * var_ref refers to the variable being
+			 * tracked e.g onmax($var).
+			 */
+			struct hist_field	*var_ref;
+
+			/*
+			 * track_var contains the 'invisible' tracking
+			 * variable created to keep the current
+			 * e.g. max value.
+			 */
+			struct hist_field	*track_var;
+
+			check_track_val_fn_t	check_val;
+			action_fn_t		save_data;
+		} track_data;
+	};
+};
+
+struct track_data {
+	u64				track_val;
+	bool				updated;
+
+	unsigned int			key_len;
+	void				*key;
+	struct tracing_map_elt		elt;
+
+	struct action_data		*action_data;
+	struct hist_trigger_data	*hist_data;
+};
+
+struct hist_elt_data {
+	char *comm;
+	u64 *var_ref_vals;
+	char **field_var_str;
+	int n_field_var_str;
+};
+
+struct snapshot_context {
+	struct tracing_map_elt	*elt;
+	void			*key;
+};
+
+/*
+ * Returns the specific division function to use if the divisor
+ * is constant. This avoids extra branches when the trigger is hit.
+ */
+static enum hist_field_fn hist_field_get_div_fn(struct hist_field *divisor)
+{
+	u64 div = divisor->constant;
+
+	if (!(div & (div - 1)))
+		return HIST_FIELD_FN_DIV_POWER2;
+
+	/* If the divisor is too large, do a regular division */
+	if (div > (1 << HIST_DIV_SHIFT))
+		return HIST_FIELD_FN_DIV_NOT_POWER2;
+
+	divisor->div_multiplier = div64_u64((u64)(1 << HIST_DIV_SHIFT), div);
+	return HIST_FIELD_FN_DIV_MULT_SHIFT;
+}
+
+static void track_data_free(struct track_data *track_data)
+{
+	struct hist_elt_data *elt_data;
+
+	if (!track_data)
+		return;
+
+	kfree(track_data->key);
+
+	elt_data = track_data->elt.private_data;
+	if (elt_data) {
+		kfree(elt_data->comm);
+		kfree(elt_data);
+	}
+
+	kfree(track_data);
+}
+
+static struct track_data *track_data_alloc(unsigned int key_len,
+					   struct action_data *action_data,
+					   struct hist_trigger_data *hist_data)
+{
+	struct track_data *data = kzalloc(sizeof(*data), GFP_KERNEL);
+	struct hist_elt_data *elt_data;
+
+	if (!data)
+		return ERR_PTR(-ENOMEM);
+
+	data->key = kzalloc(key_len, GFP_KERNEL);
+	if (!data->key) {
+		track_data_free(data);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	data->key_len = key_len;
+	data->action_data = action_data;
+	data->hist_data = hist_data;
+
+	elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
+	if (!elt_data) {
+		track_data_free(data);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	data->elt.private_data = elt_data;
+
+	elt_data->comm = kzalloc(TASK_COMM_LEN, GFP_KERNEL);
+	if (!elt_data->comm) {
+		track_data_free(data);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return data;
+}
+
+#define HIST_PREFIX "hist:"
+
+static char *last_cmd;
+static char last_cmd_loc[MAX_FILTER_STR_VAL];
+
+static int errpos(char *str)
+{
+	if (!str || !last_cmd)
+		return 0;
+
+	return err_pos(last_cmd, str);
+}
+
+static void last_cmd_set(struct trace_event_file *file, char *str)
+{
+	const char *system = NULL, *name = NULL;
+	struct trace_event_call *call;
+	int len;
+
+	if (!str)
+		return;
+
+	/* sizeof() contains the nul byte */
+	len = sizeof(HIST_PREFIX) + strlen(str);
+	kfree(last_cmd);
+	last_cmd = kzalloc(len, GFP_KERNEL);
+	if (!last_cmd)
+		return;
+
+	strcpy(last_cmd, HIST_PREFIX);
+	/* Again, sizeof() contains the nul byte */
+	len -= sizeof(HIST_PREFIX);
+	strncat(last_cmd, str, len);
+
+	if (file) {
+		call = file->event_call;
+		system = call->class->system;
+		if (system) {
+			name = trace_event_name(call);
+			if (!name)
+				system = NULL;
+		}
+	}
+
+	if (system)
+		snprintf(last_cmd_loc, MAX_FILTER_STR_VAL, HIST_PREFIX "%s:%s", system, name);
+}
+
+static void hist_err(struct trace_array *tr, u8 err_type, u16 err_pos)
+{
+	if (!last_cmd)
+		return;
+
+	tracing_log_err(tr, last_cmd_loc, last_cmd, err_text,
+			err_type, err_pos);
+}
+
+static void hist_err_clear(void)
+{
+	if (last_cmd)
+		last_cmd[0] = '\0';
+	last_cmd_loc[0] = '\0';
+}
+
+typedef void (*synth_probe_func_t) (void *__data, u64 *var_ref_vals,
+				    unsigned int *var_ref_idx);
+
+static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals,
+			       unsigned int *var_ref_idx)
+{
+	struct tracepoint *tp = event->tp;
+
+	if (unlikely(atomic_read(&tp->key.enabled) > 0)) {
+		struct tracepoint_func *probe_func_ptr;
+		synth_probe_func_t probe_func;
+		void *__data;
+
+		if (!(cpu_online(raw_smp_processor_id())))
+			return;
+
+		probe_func_ptr = rcu_dereference_sched((tp)->funcs);
+		if (probe_func_ptr) {
+			do {
+				probe_func = probe_func_ptr->func;
+				__data = probe_func_ptr->data;
+				probe_func(__data, var_ref_vals, var_ref_idx);
+			} while ((++probe_func_ptr)->func);
+		}
+	}
+}
+
+static void action_trace(struct hist_trigger_data *hist_data,
+			 struct tracing_map_elt *elt,
+			 struct trace_buffer *buffer, void *rec,
+			 struct ring_buffer_event *rbe, void *key,
+			 struct action_data *data, u64 *var_ref_vals)
+{
+	struct synth_event *event = data->synth_event;
+
+	trace_synth(event, var_ref_vals, data->var_ref_idx);
+}
+
+struct hist_var_data {
+	struct list_head list;
+	struct hist_trigger_data *hist_data;
+};
+
+static u64 hist_field_timestamp(struct hist_field *hist_field,
+				struct tracing_map_elt *elt,
+				struct trace_buffer *buffer,
+				struct ring_buffer_event *rbe,
+				void *event)
+{
+	struct hist_trigger_data *hist_data = hist_field->hist_data;
+	struct trace_array *tr = hist_data->event_file->tr;
+
+	u64 ts = ring_buffer_event_time_stamp(buffer, rbe);
+
+	if (hist_data->attrs->ts_in_usecs && trace_clock_in_ns(tr))
+		ts = ns2usecs(ts);
+
+	return ts;
+}
+
+static u64 hist_field_cpu(struct hist_field *hist_field,
+			  struct tracing_map_elt *elt,
+			  struct trace_buffer *buffer,
+			  struct ring_buffer_event *rbe,
+			  void *event)
+{
+	int cpu = smp_processor_id();
+
+	return cpu;
+}
+
+/**
+ * check_field_for_var_ref - Check if a VAR_REF field references a variable
+ * @hist_field: The VAR_REF field to check
+ * @var_data: The hist trigger that owns the variable
+ * @var_idx: The trigger variable identifier
+ *
+ * Check the given VAR_REF field to see whether or not it references
+ * the given variable associated with the given trigger.
+ *
+ * Return: The VAR_REF field if it does reference the variable, NULL if not
+ */
+static struct hist_field *
+check_field_for_var_ref(struct hist_field *hist_field,
+			struct hist_trigger_data *var_data,
+			unsigned int var_idx)
+{
+	WARN_ON(!(hist_field && hist_field->flags & HIST_FIELD_FL_VAR_REF));
+
+	if (hist_field && hist_field->var.idx == var_idx &&
+	    hist_field->var.hist_data == var_data)
+		return hist_field;
+
+	return NULL;
+}
+
+/**
+ * find_var_ref - Check if a trigger has a reference to a trigger variable
+ * @hist_data: The hist trigger that might have a reference to the variable
+ * @var_data: The hist trigger that owns the variable
+ * @var_idx: The trigger variable identifier
+ *
+ * Check the list of var_refs[] on the first hist trigger to see
+ * whether any of them are references to the variable on the second
+ * trigger.
+ *
+ * Return: The VAR_REF field referencing the variable if so, NULL if not
+ */
+static struct hist_field *find_var_ref(struct hist_trigger_data *hist_data,
+				       struct hist_trigger_data *var_data,
+				       unsigned int var_idx)
+{
+	struct hist_field *hist_field;
+	unsigned int i;
+
+	for (i = 0; i < hist_data->n_var_refs; i++) {
+		hist_field = hist_data->var_refs[i];
+		if (check_field_for_var_ref(hist_field, var_data, var_idx))
+			return hist_field;
+	}
+
+	return NULL;
+}
+
+/**
+ * find_any_var_ref - Check if there is a reference to a given trigger variable
+ * @hist_data: The hist trigger
+ * @var_idx: The trigger variable identifier
+ *
+ * Check to see whether the given variable is currently referenced by
+ * any other trigger.
+ *
+ * The trigger the variable is defined on is explicitly excluded - the
+ * assumption being that a self-reference doesn't prevent a trigger
+ * from being removed.
+ *
+ * Return: The VAR_REF field referencing the variable if so, NULL if not
+ */
+static struct hist_field *find_any_var_ref(struct hist_trigger_data *hist_data,
+					   unsigned int var_idx)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	struct hist_field *found = NULL;
+	struct hist_var_data *var_data;
+
+	list_for_each_entry(var_data, &tr->hist_vars, list) {
+		if (var_data->hist_data == hist_data)
+			continue;
+		found = find_var_ref(var_data->hist_data, hist_data, var_idx);
+		if (found)
+			break;
+	}
+
+	return found;
+}
+
+/**
+ * check_var_refs - Check if there is a reference to any of trigger's variables
+ * @hist_data: The hist trigger
+ *
+ * A trigger can define one or more variables.  If any one of them is
+ * currently referenced by any other trigger, this function will
+ * determine that.
+ *
+ * Typically used to determine whether or not a trigger can be removed
+ * - if there are any references to a trigger's variables, it cannot.
+ *
+ * Return: True if there is a reference to any of trigger's variables
+ */
+static bool check_var_refs(struct hist_trigger_data *hist_data)
+{
+	struct hist_field *field;
+	bool found = false;
+	int i;
+
+	for_each_hist_field(i, hist_data) {
+		field = hist_data->fields[i];
+		if (field && field->flags & HIST_FIELD_FL_VAR) {
+			if (find_any_var_ref(hist_data, field->var.idx)) {
+				found = true;
+				break;
+			}
+		}
+	}
+
+	return found;
+}
+
+static struct hist_var_data *find_hist_vars(struct hist_trigger_data *hist_data)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	struct hist_var_data *var_data, *found = NULL;
+
+	list_for_each_entry(var_data, &tr->hist_vars, list) {
+		if (var_data->hist_data == hist_data) {
+			found = var_data;
+			break;
+		}
+	}
+
+	return found;
+}
+
+static bool field_has_hist_vars(struct hist_field *hist_field,
+				unsigned int level)
+{
+	int i;
+
+	if (level > 3)
+		return false;
+
+	if (!hist_field)
+		return false;
+
+	if (hist_field->flags & HIST_FIELD_FL_VAR ||
+	    hist_field->flags & HIST_FIELD_FL_VAR_REF)
+		return true;
+
+	for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++) {
+		struct hist_field *operand;
+
+		operand = hist_field->operands[i];
+		if (field_has_hist_vars(operand, level + 1))
+			return true;
+	}
+
+	return false;
+}
+
+static bool has_hist_vars(struct hist_trigger_data *hist_data)
+{
+	struct hist_field *hist_field;
+	int i;
+
+	for_each_hist_field(i, hist_data) {
+		hist_field = hist_data->fields[i];
+		if (field_has_hist_vars(hist_field, 0))
+			return true;
+	}
+
+	return false;
+}
+
+static int save_hist_vars(struct hist_trigger_data *hist_data)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	struct hist_var_data *var_data;
+
+	var_data = find_hist_vars(hist_data);
+	if (var_data)
+		return 0;
+
+	if (tracing_check_open_get_tr(tr))
+		return -ENODEV;
+
+	var_data = kzalloc(sizeof(*var_data), GFP_KERNEL);
+	if (!var_data) {
+		trace_array_put(tr);
+		return -ENOMEM;
+	}
+
+	var_data->hist_data = hist_data;
+	list_add(&var_data->list, &tr->hist_vars);
+
+	return 0;
+}
+
+static void remove_hist_vars(struct hist_trigger_data *hist_data)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	struct hist_var_data *var_data;
+
+	var_data = find_hist_vars(hist_data);
+	if (!var_data)
+		return;
+
+	if (WARN_ON(check_var_refs(hist_data)))
+		return;
+
+	list_del(&var_data->list);
+
+	kfree(var_data);
+
+	trace_array_put(tr);
+}
+
+static struct hist_field *find_var_field(struct hist_trigger_data *hist_data,
+					 const char *var_name)
+{
+	struct hist_field *hist_field, *found = NULL;
+	int i;
+
+	for_each_hist_field(i, hist_data) {
+		hist_field = hist_data->fields[i];
+		if (hist_field && hist_field->flags & HIST_FIELD_FL_VAR &&
+		    strcmp(hist_field->var.name, var_name) == 0) {
+			found = hist_field;
+			break;
+		}
+	}
+
+	return found;
+}
+
+static struct hist_field *find_var(struct hist_trigger_data *hist_data,
+				   struct trace_event_file *file,
+				   const char *var_name)
+{
+	struct hist_trigger_data *test_data;
+	struct event_trigger_data *test;
+	struct hist_field *hist_field;
+
+	lockdep_assert_held(&event_mutex);
+
+	hist_field = find_var_field(hist_data, var_name);
+	if (hist_field)
+		return hist_field;
+
+	list_for_each_entry(test, &file->triggers, list) {
+		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+			test_data = test->private_data;
+			hist_field = find_var_field(test_data, var_name);
+			if (hist_field)
+				return hist_field;
+		}
+	}
+
+	return NULL;
+}
+
+static struct trace_event_file *find_var_file(struct trace_array *tr,
+					      char *system,
+					      char *event_name,
+					      char *var_name)
+{
+	struct hist_trigger_data *var_hist_data;
+	struct hist_var_data *var_data;
+	struct trace_event_file *file, *found = NULL;
+
+	if (system)
+		return find_event_file(tr, system, event_name);
+
+	list_for_each_entry(var_data, &tr->hist_vars, list) {
+		var_hist_data = var_data->hist_data;
+		file = var_hist_data->event_file;
+		if (file == found)
+			continue;
+
+		if (find_var_field(var_hist_data, var_name)) {
+			if (found) {
+				hist_err(tr, HIST_ERR_VAR_NOT_UNIQUE, errpos(var_name));
+				return NULL;
+			}
+
+			found = file;
+		}
+	}
+
+	return found;
+}
+
+static struct hist_field *find_file_var(struct trace_event_file *file,
+					const char *var_name)
+{
+	struct hist_trigger_data *test_data;
+	struct event_trigger_data *test;
+	struct hist_field *hist_field;
+
+	lockdep_assert_held(&event_mutex);
+
+	list_for_each_entry(test, &file->triggers, list) {
+		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+			test_data = test->private_data;
+			hist_field = find_var_field(test_data, var_name);
+			if (hist_field)
+				return hist_field;
+		}
+	}
+
+	return NULL;
+}
+
+static struct hist_field *
+find_match_var(struct hist_trigger_data *hist_data, char *var_name)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	struct hist_field *hist_field, *found = NULL;
+	struct trace_event_file *file;
+	unsigned int i;
+
+	for (i = 0; i < hist_data->n_actions; i++) {
+		struct action_data *data = hist_data->actions[i];
+
+		if (data->handler == HANDLER_ONMATCH) {
+			char *system = data->match_data.event_system;
+			char *event_name = data->match_data.event;
+
+			file = find_var_file(tr, system, event_name, var_name);
+			if (!file)
+				continue;
+			hist_field = find_file_var(file, var_name);
+			if (hist_field) {
+				if (found) {
+					hist_err(tr, HIST_ERR_VAR_NOT_UNIQUE,
+						 errpos(var_name));
+					return ERR_PTR(-EINVAL);
+				}
+
+				found = hist_field;
+			}
+		}
+	}
+	return found;
+}
+
+static struct hist_field *find_event_var(struct hist_trigger_data *hist_data,
+					 char *system,
+					 char *event_name,
+					 char *var_name)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	struct hist_field *hist_field = NULL;
+	struct trace_event_file *file;
+
+	if (!system || !event_name) {
+		hist_field = find_match_var(hist_data, var_name);
+		if (IS_ERR(hist_field))
+			return NULL;
+		if (hist_field)
+			return hist_field;
+	}
+
+	file = find_var_file(tr, system, event_name, var_name);
+	if (!file)
+		return NULL;
+
+	hist_field = find_file_var(file, var_name);
+
+	return hist_field;
+}
+
+static u64 hist_field_var_ref(struct hist_field *hist_field,
+			      struct tracing_map_elt *elt,
+			      struct trace_buffer *buffer,
+			      struct ring_buffer_event *rbe,
+			      void *event)
+{
+	struct hist_elt_data *elt_data;
+	u64 var_val = 0;
+
+	if (WARN_ON_ONCE(!elt))
+		return var_val;
+
+	elt_data = elt->private_data;
+	var_val = elt_data->var_ref_vals[hist_field->var_ref_idx];
+
+	return var_val;
+}
+
+static bool resolve_var_refs(struct hist_trigger_data *hist_data, void *key,
+			     u64 *var_ref_vals, bool self)
+{
+	struct hist_trigger_data *var_data;
+	struct tracing_map_elt *var_elt;
+	struct hist_field *hist_field;
+	unsigned int i, var_idx;
+	bool resolved = true;
+	u64 var_val = 0;
+
+	for (i = 0; i < hist_data->n_var_refs; i++) {
+		hist_field = hist_data->var_refs[i];
+		var_idx = hist_field->var.idx;
+		var_data = hist_field->var.hist_data;
+
+		if (var_data == NULL) {
+			resolved = false;
+			break;
+		}
+
+		if ((self && var_data != hist_data) ||
+		    (!self && var_data == hist_data))
+			continue;
+
+		var_elt = tracing_map_lookup(var_data->map, key);
+		if (!var_elt) {
+			resolved = false;
+			break;
+		}
+
+		if (!tracing_map_var_set(var_elt, var_idx)) {
+			resolved = false;
+			break;
+		}
+
+		if (self || !hist_field->read_once)
+			var_val = tracing_map_read_var(var_elt, var_idx);
+		else
+			var_val = tracing_map_read_var_once(var_elt, var_idx);
+
+		var_ref_vals[i] = var_val;
+	}
+
+	return resolved;
+}
+
+static const char *hist_field_name(struct hist_field *field,
+				   unsigned int level)
+{
+	const char *field_name = "";
+
+	if (WARN_ON_ONCE(!field))
+		return field_name;
+
+	if (level > 1)
+		return field_name;
+
+	if (field->field)
+		field_name = field->field->name;
+	else if (field->flags & HIST_FIELD_FL_LOG2 ||
+		 field->flags & HIST_FIELD_FL_ALIAS ||
+		 field->flags & HIST_FIELD_FL_BUCKET)
+		field_name = hist_field_name(field->operands[0], ++level);
+	else if (field->flags & HIST_FIELD_FL_CPU)
+		field_name = "common_cpu";
+	else if (field->flags & HIST_FIELD_FL_EXPR ||
+		 field->flags & HIST_FIELD_FL_VAR_REF) {
+		if (field->system) {
+			static char full_name[MAX_FILTER_STR_VAL];
+
+			strcat(full_name, field->system);
+			strcat(full_name, ".");
+			strcat(full_name, field->event_name);
+			strcat(full_name, ".");
+			strcat(full_name, field->name);
+			field_name = full_name;
+		} else
+			field_name = field->name;
+	} else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
+		field_name = "common_timestamp";
+
+	if (field_name == NULL)
+		field_name = "";
+
+	return field_name;
+}
+
+static enum hist_field_fn select_value_fn(int field_size, int field_is_signed)
+{
+	switch (field_size) {
+	case 8:
+		if (field_is_signed)
+			return HIST_FIELD_FN_S64;
+		else
+			return HIST_FIELD_FN_U64;
+	case 4:
+		if (field_is_signed)
+			return HIST_FIELD_FN_S32;
+		else
+			return HIST_FIELD_FN_U32;
+	case 2:
+		if (field_is_signed)
+			return HIST_FIELD_FN_S16;
+		else
+			return HIST_FIELD_FN_U16;
+	case 1:
+		if (field_is_signed)
+			return HIST_FIELD_FN_S8;
+		else
+			return HIST_FIELD_FN_U8;
+	}
+
+	return HIST_FIELD_FN_NOP;
+}
+
+static int parse_map_size(char *str)
+{
+	unsigned long size, map_bits;
+	int ret;
+
+	ret = kstrtoul(str, 0, &size);
+	if (ret)
+		goto out;
+
+	map_bits = ilog2(roundup_pow_of_two(size));
+	if (map_bits < TRACING_MAP_BITS_MIN ||
+	    map_bits > TRACING_MAP_BITS_MAX)
+		ret = -EINVAL;
+	else
+		ret = map_bits;
+ out:
+	return ret;
+}
+
+static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)
+{
+	unsigned int i;
+
+	if (!attrs)
+		return;
+
+	for (i = 0; i < attrs->n_assignments; i++)
+		kfree(attrs->assignment_str[i]);
+
+	for (i = 0; i < attrs->n_actions; i++)
+		kfree(attrs->action_str[i]);
+
+	kfree(attrs->name);
+	kfree(attrs->sort_key_str);
+	kfree(attrs->keys_str);
+	kfree(attrs->vals_str);
+	kfree(attrs->clock);
+	kfree(attrs);
+}
+
+static int parse_action(char *str, struct hist_trigger_attrs *attrs)
+{
+	int ret = -EINVAL;
+
+	if (attrs->n_actions >= HIST_ACTIONS_MAX)
+		return ret;
+
+	if ((str_has_prefix(str, "onmatch(")) ||
+	    (str_has_prefix(str, "onmax(")) ||
+	    (str_has_prefix(str, "onchange("))) {
+		attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL);
+		if (!attrs->action_str[attrs->n_actions]) {
+			ret = -ENOMEM;
+			return ret;
+		}
+		attrs->n_actions++;
+		ret = 0;
+	}
+	return ret;
+}
+
+static int parse_assignment(struct trace_array *tr,
+			    char *str, struct hist_trigger_attrs *attrs)
+{
+	int len, ret = 0;
+
+	if ((len = str_has_prefix(str, "key=")) ||
+	    (len = str_has_prefix(str, "keys="))) {
+		attrs->keys_str = kstrdup(str + len, GFP_KERNEL);
+		if (!attrs->keys_str) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	} else if ((len = str_has_prefix(str, "val=")) ||
+		   (len = str_has_prefix(str, "vals=")) ||
+		   (len = str_has_prefix(str, "values="))) {
+		attrs->vals_str = kstrdup(str + len, GFP_KERNEL);
+		if (!attrs->vals_str) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	} else if ((len = str_has_prefix(str, "sort="))) {
+		attrs->sort_key_str = kstrdup(str + len, GFP_KERNEL);
+		if (!attrs->sort_key_str) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	} else if (str_has_prefix(str, "name=")) {
+		attrs->name = kstrdup(str, GFP_KERNEL);
+		if (!attrs->name) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	} else if ((len = str_has_prefix(str, "clock="))) {
+		str += len;
+
+		str = strstrip(str);
+		attrs->clock = kstrdup(str, GFP_KERNEL);
+		if (!attrs->clock) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	} else if ((len = str_has_prefix(str, "size="))) {
+		int map_bits = parse_map_size(str + len);
+
+		if (map_bits < 0) {
+			ret = map_bits;
+			goto out;
+		}
+		attrs->map_bits = map_bits;
+	} else {
+		char *assignment;
+
+		if (attrs->n_assignments == TRACING_MAP_VARS_MAX) {
+			hist_err(tr, HIST_ERR_TOO_MANY_VARS, errpos(str));
+			ret = -EINVAL;
+			goto out;
+		}
+
+		assignment = kstrdup(str, GFP_KERNEL);
+		if (!assignment) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		attrs->assignment_str[attrs->n_assignments++] = assignment;
+	}
+ out:
+	return ret;
+}
+
+static struct hist_trigger_attrs *
+parse_hist_trigger_attrs(struct trace_array *tr, char *trigger_str)
+{
+	struct hist_trigger_attrs *attrs;
+	int ret = 0;
+
+	attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
+	if (!attrs)
+		return ERR_PTR(-ENOMEM);
+
+	while (trigger_str) {
+		char *str = strsep(&trigger_str, ":");
+		char *rhs;
+
+		rhs = strchr(str, '=');
+		if (rhs) {
+			if (!strlen(++rhs)) {
+				ret = -EINVAL;
+				hist_err(tr, HIST_ERR_EMPTY_ASSIGNMENT, errpos(str));
+				goto free;
+			}
+			ret = parse_assignment(tr, str, attrs);
+			if (ret)
+				goto free;
+		} else if (strcmp(str, "pause") == 0)
+			attrs->pause = true;
+		else if ((strcmp(str, "cont") == 0) ||
+			 (strcmp(str, "continue") == 0))
+			attrs->cont = true;
+		else if (strcmp(str, "clear") == 0)
+			attrs->clear = true;
+		else {
+			ret = parse_action(str, attrs);
+			if (ret)
+				goto free;
+		}
+	}
+
+	if (!attrs->keys_str) {
+		ret = -EINVAL;
+		goto free;
+	}
+
+	if (!attrs->clock) {
+		attrs->clock = kstrdup("global", GFP_KERNEL);
+		if (!attrs->clock) {
+			ret = -ENOMEM;
+			goto free;
+		}
+	}
+
+	return attrs;
+ free:
+	destroy_hist_trigger_attrs(attrs);
+
+	return ERR_PTR(ret);
+}
+
+static inline void save_comm(char *comm, struct task_struct *task)
+{
+	if (!task->pid) {
+		strcpy(comm, "<idle>");
+		return;
+	}
+
+	if (WARN_ON_ONCE(task->pid < 0)) {
+		strcpy(comm, "<XXX>");
+		return;
+	}
+
+	strncpy(comm, task->comm, TASK_COMM_LEN);
+}
+
+static void hist_elt_data_free(struct hist_elt_data *elt_data)
+{
+	unsigned int i;
+
+	for (i = 0; i < elt_data->n_field_var_str; i++)
+		kfree(elt_data->field_var_str[i]);
+
+	kfree(elt_data->field_var_str);
+
+	kfree(elt_data->comm);
+	kfree(elt_data);
+}
+
+static void hist_trigger_elt_data_free(struct tracing_map_elt *elt)
+{
+	struct hist_elt_data *elt_data = elt->private_data;
+
+	hist_elt_data_free(elt_data);
+}
+
+static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt)
+{
+	struct hist_trigger_data *hist_data = elt->map->private_data;
+	unsigned int size = TASK_COMM_LEN;
+	struct hist_elt_data *elt_data;
+	struct hist_field *hist_field;
+	unsigned int i, n_str;
+
+	elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
+	if (!elt_data)
+		return -ENOMEM;
+
+	for_each_hist_field(i, hist_data) {
+		hist_field = hist_data->fields[i];
+
+		if (hist_field->flags & HIST_FIELD_FL_EXECNAME) {
+			elt_data->comm = kzalloc(size, GFP_KERNEL);
+			if (!elt_data->comm) {
+				kfree(elt_data);
+				return -ENOMEM;
+			}
+			break;
+		}
+	}
+
+	n_str = hist_data->n_field_var_str + hist_data->n_save_var_str +
+		hist_data->n_var_str;
+	if (n_str > SYNTH_FIELDS_MAX) {
+		hist_elt_data_free(elt_data);
+		return -EINVAL;
+	}
+
+	BUILD_BUG_ON(STR_VAR_LEN_MAX & (sizeof(u64) - 1));
+
+	size = STR_VAR_LEN_MAX;
+
+	elt_data->field_var_str = kcalloc(n_str, sizeof(char *), GFP_KERNEL);
+	if (!elt_data->field_var_str) {
+		hist_elt_data_free(elt_data);
+		return -EINVAL;
+	}
+	elt_data->n_field_var_str = n_str;
+
+	for (i = 0; i < n_str; i++) {
+		elt_data->field_var_str[i] = kzalloc(size, GFP_KERNEL);
+		if (!elt_data->field_var_str[i]) {
+			hist_elt_data_free(elt_data);
+			return -ENOMEM;
+		}
+	}
+
+	elt->private_data = elt_data;
+
+	return 0;
+}
+
+static void hist_trigger_elt_data_init(struct tracing_map_elt *elt)
+{
+	struct hist_elt_data *elt_data = elt->private_data;
+
+	if (elt_data->comm)
+		save_comm(elt_data->comm, current);
+}
+
+static const struct tracing_map_ops hist_trigger_elt_data_ops = {
+	.elt_alloc	= hist_trigger_elt_data_alloc,
+	.elt_free	= hist_trigger_elt_data_free,
+	.elt_init	= hist_trigger_elt_data_init,
+};
+
+static const char *get_hist_field_flags(struct hist_field *hist_field)
+{
+	const char *flags_str = NULL;
+
+	if (hist_field->flags & HIST_FIELD_FL_HEX)
+		flags_str = "hex";
+	else if (hist_field->flags & HIST_FIELD_FL_SYM)
+		flags_str = "sym";
+	else if (hist_field->flags & HIST_FIELD_FL_SYM_OFFSET)
+		flags_str = "sym-offset";
+	else if (hist_field->flags & HIST_FIELD_FL_EXECNAME)
+		flags_str = "execname";
+	else if (hist_field->flags & HIST_FIELD_FL_SYSCALL)
+		flags_str = "syscall";
+	else if (hist_field->flags & HIST_FIELD_FL_LOG2)
+		flags_str = "log2";
+	else if (hist_field->flags & HIST_FIELD_FL_BUCKET)
+		flags_str = "buckets";
+	else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP_USECS)
+		flags_str = "usecs";
+	else if (hist_field->flags & HIST_FIELD_FL_PERCENT)
+		flags_str = "percent";
+	else if (hist_field->flags & HIST_FIELD_FL_GRAPH)
+		flags_str = "graph";
+
+	return flags_str;
+}
+
+static void expr_field_str(struct hist_field *field, char *expr)
+{
+	if (field->flags & HIST_FIELD_FL_VAR_REF)
+		strcat(expr, "$");
+	else if (field->flags & HIST_FIELD_FL_CONST) {
+		char str[HIST_CONST_DIGITS_MAX];
+
+		snprintf(str, HIST_CONST_DIGITS_MAX, "%llu", field->constant);
+		strcat(expr, str);
+	}
+
+	strcat(expr, hist_field_name(field, 0));
+
+	if (field->flags && !(field->flags & HIST_FIELD_FL_VAR_REF)) {
+		const char *flags_str = get_hist_field_flags(field);
+
+		if (flags_str) {
+			strcat(expr, ".");
+			strcat(expr, flags_str);
+		}
+	}
+}
+
+static char *expr_str(struct hist_field *field, unsigned int level)
+{
+	char *expr;
+
+	if (level > 1)
+		return NULL;
+
+	expr = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
+	if (!expr)
+		return NULL;
+
+	if (!field->operands[0]) {
+		expr_field_str(field, expr);
+		return expr;
+	}
+
+	if (field->operator == FIELD_OP_UNARY_MINUS) {
+		char *subexpr;
+
+		strcat(expr, "-(");
+		subexpr = expr_str(field->operands[0], ++level);
+		if (!subexpr) {
+			kfree(expr);
+			return NULL;
+		}
+		strcat(expr, subexpr);
+		strcat(expr, ")");
+
+		kfree(subexpr);
+
+		return expr;
+	}
+
+	expr_field_str(field->operands[0], expr);
+
+	switch (field->operator) {
+	case FIELD_OP_MINUS:
+		strcat(expr, "-");
+		break;
+	case FIELD_OP_PLUS:
+		strcat(expr, "+");
+		break;
+	case FIELD_OP_DIV:
+		strcat(expr, "/");
+		break;
+	case FIELD_OP_MULT:
+		strcat(expr, "*");
+		break;
+	default:
+		kfree(expr);
+		return NULL;
+	}
+
+	expr_field_str(field->operands[1], expr);
+
+	return expr;
+}
+
+/*
+ * If field_op != FIELD_OP_NONE, *sep points to the root operator
+ * of the expression tree to be evaluated.
+ */
+static int contains_operator(char *str, char **sep)
+{
+	enum field_op_id field_op = FIELD_OP_NONE;
+	char *minus_op, *plus_op, *div_op, *mult_op;
+
+
+	/*
+	 * Report the last occurrence of the operators first, so that the
+	 * expression is evaluated left to right. This is important since
+	 * subtraction and division are not associative.
+	 *
+	 *	e.g
+	 *		64/8/4/2 is 1, i.e 64/8/4/2 = ((64/8)/4)/2
+	 *		14-7-5-2 is 0, i.e 14-7-5-2 = ((14-7)-5)-2
+	 */
+
+	/*
+	 * First, find lower precedence addition and subtraction
+	 * since the expression will be evaluated recursively.
+	 */
+	minus_op = strrchr(str, '-');
+	if (minus_op) {
+		/*
+		 * Unary minus is not supported in sub-expressions. If
+		 * present, it is always the next root operator.
+		 */
+		if (minus_op == str) {
+			field_op = FIELD_OP_UNARY_MINUS;
+			goto out;
+		}
+
+		field_op = FIELD_OP_MINUS;
+	}
+
+	plus_op = strrchr(str, '+');
+	if (plus_op || minus_op) {
+		/*
+		 * For operators of the same precedence use to rightmost as the
+		 * root, so that the expression is evaluated left to right.
+		 */
+		if (plus_op > minus_op)
+			field_op = FIELD_OP_PLUS;
+		goto out;
+	}
+
+	/*
+	 * Multiplication and division have higher precedence than addition and
+	 * subtraction.
+	 */
+	div_op = strrchr(str, '/');
+	if (div_op)
+		field_op = FIELD_OP_DIV;
+
+	mult_op = strrchr(str, '*');
+	/*
+	 * For operators of the same precedence use to rightmost as the
+	 * root, so that the expression is evaluated left to right.
+	 */
+	if (mult_op > div_op)
+		field_op = FIELD_OP_MULT;
+
+out:
+	if (sep) {
+		switch (field_op) {
+		case FIELD_OP_UNARY_MINUS:
+		case FIELD_OP_MINUS:
+			*sep = minus_op;
+			break;
+		case FIELD_OP_PLUS:
+			*sep = plus_op;
+			break;
+		case FIELD_OP_DIV:
+			*sep = div_op;
+			break;
+		case FIELD_OP_MULT:
+			*sep = mult_op;
+			break;
+		case FIELD_OP_NONE:
+		default:
+			*sep = NULL;
+			break;
+		}
+	}
+
+	return field_op;
+}
+
+static void get_hist_field(struct hist_field *hist_field)
+{
+	hist_field->ref++;
+}
+
+static void __destroy_hist_field(struct hist_field *hist_field)
+{
+	if (--hist_field->ref > 1)
+		return;
+
+	kfree(hist_field->var.name);
+	kfree(hist_field->name);
+
+	/* Can likely be a const */
+	kfree_const(hist_field->type);
+
+	kfree(hist_field->system);
+	kfree(hist_field->event_name);
+
+	kfree(hist_field);
+}
+
+static void destroy_hist_field(struct hist_field *hist_field,
+			       unsigned int level)
+{
+	unsigned int i;
+
+	if (level > 3)
+		return;
+
+	if (!hist_field)
+		return;
+
+	if (hist_field->flags & HIST_FIELD_FL_VAR_REF)
+		return; /* var refs will be destroyed separately */
+
+	for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++)
+		destroy_hist_field(hist_field->operands[i], level + 1);
+
+	__destroy_hist_field(hist_field);
+}
+
+static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
+					    struct ftrace_event_field *field,
+					    unsigned long flags,
+					    char *var_name)
+{
+	struct hist_field *hist_field;
+
+	if (field && is_function_field(field))
+		return NULL;
+
+	hist_field = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
+	if (!hist_field)
+		return NULL;
+
+	hist_field->ref = 1;
+
+	hist_field->hist_data = hist_data;
+
+	if (flags & HIST_FIELD_FL_EXPR || flags & HIST_FIELD_FL_ALIAS)
+		goto out; /* caller will populate */
+
+	if (flags & HIST_FIELD_FL_VAR_REF) {
+		hist_field->fn_num = HIST_FIELD_FN_VAR_REF;
+		goto out;
+	}
+
+	if (flags & HIST_FIELD_FL_HITCOUNT) {
+		hist_field->fn_num = HIST_FIELD_FN_COUNTER;
+		hist_field->size = sizeof(u64);
+		hist_field->type = "u64";
+		goto out;
+	}
+
+	if (flags & HIST_FIELD_FL_CONST) {
+		hist_field->fn_num = HIST_FIELD_FN_CONST;
+		hist_field->size = sizeof(u64);
+		hist_field->type = kstrdup("u64", GFP_KERNEL);
+		if (!hist_field->type)
+			goto free;
+		goto out;
+	}
+
+	if (flags & HIST_FIELD_FL_STACKTRACE) {
+		hist_field->fn_num = HIST_FIELD_FN_NOP;
+		goto out;
+	}
+
+	if (flags & (HIST_FIELD_FL_LOG2 | HIST_FIELD_FL_BUCKET)) {
+		unsigned long fl = flags & ~(HIST_FIELD_FL_LOG2 | HIST_FIELD_FL_BUCKET);
+		hist_field->fn_num = flags & HIST_FIELD_FL_LOG2 ? HIST_FIELD_FN_LOG2 :
+			HIST_FIELD_FN_BUCKET;
+		hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL);
+		if (!hist_field->operands[0])
+			goto free;
+		hist_field->size = hist_field->operands[0]->size;
+		hist_field->type = kstrdup_const(hist_field->operands[0]->type, GFP_KERNEL);
+		if (!hist_field->type)
+			goto free;
+		goto out;
+	}
+
+	if (flags & HIST_FIELD_FL_TIMESTAMP) {
+		hist_field->fn_num = HIST_FIELD_FN_TIMESTAMP;
+		hist_field->size = sizeof(u64);
+		hist_field->type = "u64";
+		goto out;
+	}
+
+	if (flags & HIST_FIELD_FL_CPU) {
+		hist_field->fn_num = HIST_FIELD_FN_CPU;
+		hist_field->size = sizeof(int);
+		hist_field->type = "unsigned int";
+		goto out;
+	}
+
+	if (WARN_ON_ONCE(!field))
+		goto out;
+
+	/* Pointers to strings are just pointers and dangerous to dereference */
+	if (is_string_field(field) &&
+	    (field->filter_type != FILTER_PTR_STRING)) {
+		flags |= HIST_FIELD_FL_STRING;
+
+		hist_field->size = MAX_FILTER_STR_VAL;
+		hist_field->type = kstrdup_const(field->type, GFP_KERNEL);
+		if (!hist_field->type)
+			goto free;
+
+		if (field->filter_type == FILTER_STATIC_STRING) {
+			hist_field->fn_num = HIST_FIELD_FN_STRING;
+			hist_field->size = field->size;
+		} else if (field->filter_type == FILTER_DYN_STRING) {
+			hist_field->fn_num = HIST_FIELD_FN_DYNSTRING;
+		} else if (field->filter_type == FILTER_RDYN_STRING)
+			hist_field->fn_num = HIST_FIELD_FN_RELDYNSTRING;
+		else
+			hist_field->fn_num = HIST_FIELD_FN_PSTRING;
+	} else {
+		hist_field->size = field->size;
+		hist_field->is_signed = field->is_signed;
+		hist_field->type = kstrdup_const(field->type, GFP_KERNEL);
+		if (!hist_field->type)
+			goto free;
+
+		hist_field->fn_num = select_value_fn(field->size,
+						     field->is_signed);
+		if (hist_field->fn_num == HIST_FIELD_FN_NOP) {
+			destroy_hist_field(hist_field, 0);
+			return NULL;
+		}
+	}
+ out:
+	hist_field->field = field;
+	hist_field->flags = flags;
+
+	if (var_name) {
+		hist_field->var.name = kstrdup(var_name, GFP_KERNEL);
+		if (!hist_field->var.name)
+			goto free;
+	}
+
+	return hist_field;
+ free:
+	destroy_hist_field(hist_field, 0);
+	return NULL;
+}
+
+static void destroy_hist_fields(struct hist_trigger_data *hist_data)
+{
+	unsigned int i;
+
+	for (i = 0; i < HIST_FIELDS_MAX; i++) {
+		if (hist_data->fields[i]) {
+			destroy_hist_field(hist_data->fields[i], 0);
+			hist_data->fields[i] = NULL;
+		}
+	}
+
+	for (i = 0; i < hist_data->n_var_refs; i++) {
+		WARN_ON(!(hist_data->var_refs[i]->flags & HIST_FIELD_FL_VAR_REF));
+		__destroy_hist_field(hist_data->var_refs[i]);
+		hist_data->var_refs[i] = NULL;
+	}
+}
+
+static int init_var_ref(struct hist_field *ref_field,
+			struct hist_field *var_field,
+			char *system, char *event_name)
+{
+	int err = 0;
+
+	ref_field->var.idx = var_field->var.idx;
+	ref_field->var.hist_data = var_field->hist_data;
+	ref_field->size = var_field->size;
+	ref_field->is_signed = var_field->is_signed;
+	ref_field->flags |= var_field->flags &
+		(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
+
+	if (system) {
+		ref_field->system = kstrdup(system, GFP_KERNEL);
+		if (!ref_field->system)
+			return -ENOMEM;
+	}
+
+	if (event_name) {
+		ref_field->event_name = kstrdup(event_name, GFP_KERNEL);
+		if (!ref_field->event_name) {
+			err = -ENOMEM;
+			goto free;
+		}
+	}
+
+	if (var_field->var.name) {
+		ref_field->name = kstrdup(var_field->var.name, GFP_KERNEL);
+		if (!ref_field->name) {
+			err = -ENOMEM;
+			goto free;
+		}
+	} else if (var_field->name) {
+		ref_field->name = kstrdup(var_field->name, GFP_KERNEL);
+		if (!ref_field->name) {
+			err = -ENOMEM;
+			goto free;
+		}
+	}
+
+	ref_field->type = kstrdup_const(var_field->type, GFP_KERNEL);
+	if (!ref_field->type) {
+		err = -ENOMEM;
+		goto free;
+	}
+ out:
+	return err;
+ free:
+	kfree(ref_field->system);
+	ref_field->system = NULL;
+	kfree(ref_field->event_name);
+	ref_field->event_name = NULL;
+	kfree(ref_field->name);
+	ref_field->name = NULL;
+
+	goto out;
+}
+
+static int find_var_ref_idx(struct hist_trigger_data *hist_data,
+			    struct hist_field *var_field)
+{
+	struct hist_field *ref_field;
+	int i;
+
+	for (i = 0; i < hist_data->n_var_refs; i++) {
+		ref_field = hist_data->var_refs[i];
+		if (ref_field->var.idx == var_field->var.idx &&
+		    ref_field->var.hist_data == var_field->hist_data)
+			return i;
+	}
+
+	return -ENOENT;
+}
+
+/**
+ * create_var_ref - Create a variable reference and attach it to trigger
+ * @hist_data: The trigger that will be referencing the variable
+ * @var_field: The VAR field to create a reference to
+ * @system: The optional system string
+ * @event_name: The optional event_name string
+ *
+ * Given a variable hist_field, create a VAR_REF hist_field that
+ * represents a reference to it.
+ *
+ * This function also adds the reference to the trigger that
+ * now references the variable.
+ *
+ * Return: The VAR_REF field if successful, NULL if not
+ */
+static struct hist_field *create_var_ref(struct hist_trigger_data *hist_data,
+					 struct hist_field *var_field,
+					 char *system, char *event_name)
+{
+	unsigned long flags = HIST_FIELD_FL_VAR_REF;
+	struct hist_field *ref_field;
+	int i;
+
+	/* Check if the variable already exists */
+	for (i = 0; i < hist_data->n_var_refs; i++) {
+		ref_field = hist_data->var_refs[i];
+		if (ref_field->var.idx == var_field->var.idx &&
+		    ref_field->var.hist_data == var_field->hist_data) {
+			get_hist_field(ref_field);
+			return ref_field;
+		}
+	}
+	/* Sanity check to avoid out-of-bound write on 'hist_data->var_refs' */
+	if (hist_data->n_var_refs >= TRACING_MAP_VARS_MAX)
+		return NULL;
+	ref_field = create_hist_field(var_field->hist_data, NULL, flags, NULL);
+	if (ref_field) {
+		if (init_var_ref(ref_field, var_field, system, event_name)) {
+			destroy_hist_field(ref_field, 0);
+			return NULL;
+		}
+
+		hist_data->var_refs[hist_data->n_var_refs] = ref_field;
+		ref_field->var_ref_idx = hist_data->n_var_refs++;
+	}
+
+	return ref_field;
+}
+
+static bool is_var_ref(char *var_name)
+{
+	if (!var_name || strlen(var_name) < 2 || var_name[0] != '$')
+		return false;
+
+	return true;
+}
+
+static char *field_name_from_var(struct hist_trigger_data *hist_data,
+				 char *var_name)
+{
+	char *name, *field;
+	unsigned int i;
+
+	for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
+		name = hist_data->attrs->var_defs.name[i];
+
+		if (strcmp(var_name, name) == 0) {
+			field = hist_data->attrs->var_defs.expr[i];
+			if (contains_operator(field, NULL) || is_var_ref(field))
+				continue;
+			return field;
+		}
+	}
+
+	return NULL;
+}
+
+static char *local_field_var_ref(struct hist_trigger_data *hist_data,
+				 char *system, char *event_name,
+				 char *var_name)
+{
+	struct trace_event_call *call;
+
+	if (system && event_name) {
+		call = hist_data->event_file->event_call;
+
+		if (strcmp(system, call->class->system) != 0)
+			return NULL;
+
+		if (strcmp(event_name, trace_event_name(call)) != 0)
+			return NULL;
+	}
+
+	if (!!system != !!event_name)
+		return NULL;
+
+	if (!is_var_ref(var_name))
+		return NULL;
+
+	var_name++;
+
+	return field_name_from_var(hist_data, var_name);
+}
+
+static struct hist_field *parse_var_ref(struct hist_trigger_data *hist_data,
+					char *system, char *event_name,
+					char *var_name)
+{
+	struct hist_field *var_field = NULL, *ref_field = NULL;
+	struct trace_array *tr = hist_data->event_file->tr;
+
+	if (!is_var_ref(var_name))
+		return NULL;
+
+	var_name++;
+
+	var_field = find_event_var(hist_data, system, event_name, var_name);
+	if (var_field)
+		ref_field = create_var_ref(hist_data, var_field,
+					   system, event_name);
+
+	if (!ref_field)
+		hist_err(tr, HIST_ERR_VAR_NOT_FOUND, errpos(var_name));
+
+	return ref_field;
+}
+
+static struct ftrace_event_field *
+parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
+	    char *field_str, unsigned long *flags, unsigned long *buckets)
+{
+	struct ftrace_event_field *field = NULL;
+	char *field_name, *modifier, *str;
+	struct trace_array *tr = file->tr;
+
+	modifier = str = kstrdup(field_str, GFP_KERNEL);
+	if (!modifier)
+		return ERR_PTR(-ENOMEM);
+
+	field_name = strsep(&modifier, ".");
+	if (modifier) {
+		if (strcmp(modifier, "hex") == 0)
+			*flags |= HIST_FIELD_FL_HEX;
+		else if (strcmp(modifier, "sym") == 0)
+			*flags |= HIST_FIELD_FL_SYM;
+		/*
+		 * 'sym-offset' occurrences in the trigger string are modified
+		 * to 'symXoffset' to simplify arithmetic expression parsing.
+		 */
+		else if (strcmp(modifier, "symXoffset") == 0)
+			*flags |= HIST_FIELD_FL_SYM_OFFSET;
+		else if ((strcmp(modifier, "execname") == 0) &&
+			 (strcmp(field_name, "common_pid") == 0))
+			*flags |= HIST_FIELD_FL_EXECNAME;
+		else if (strcmp(modifier, "syscall") == 0)
+			*flags |= HIST_FIELD_FL_SYSCALL;
+		else if (strcmp(modifier, "log2") == 0)
+			*flags |= HIST_FIELD_FL_LOG2;
+		else if (strcmp(modifier, "usecs") == 0)
+			*flags |= HIST_FIELD_FL_TIMESTAMP_USECS;
+		else if (strncmp(modifier, "bucket", 6) == 0) {
+			int ret;
+
+			modifier += 6;
+
+			if (*modifier == 's')
+				modifier++;
+			if (*modifier != '=')
+				goto error;
+			modifier++;
+			ret = kstrtoul(modifier, 0, buckets);
+			if (ret || !(*buckets))
+				goto error;
+			*flags |= HIST_FIELD_FL_BUCKET;
+		} else if (strncmp(modifier, "percent", 7) == 0) {
+			if (*flags & (HIST_FIELD_FL_VAR | HIST_FIELD_FL_KEY))
+				goto error;
+			*flags |= HIST_FIELD_FL_PERCENT;
+		} else if (strncmp(modifier, "graph", 5) == 0) {
+			if (*flags & (HIST_FIELD_FL_VAR | HIST_FIELD_FL_KEY))
+				goto error;
+			*flags |= HIST_FIELD_FL_GRAPH;
+		} else {
+ error:
+			hist_err(tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(modifier));
+			field = ERR_PTR(-EINVAL);
+			goto out;
+		}
+	}
+
+	if (strcmp(field_name, "common_timestamp") == 0) {
+		*flags |= HIST_FIELD_FL_TIMESTAMP;
+		hist_data->enable_timestamps = true;
+		if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)
+			hist_data->attrs->ts_in_usecs = true;
+	} else if (strcmp(field_name, "common_cpu") == 0)
+		*flags |= HIST_FIELD_FL_CPU;
+	else {
+		field = trace_find_event_field(file->event_call, field_name);
+		if (!field || !field->size) {
+			/*
+			 * For backward compatibility, if field_name
+			 * was "cpu", then we treat this the same as
+			 * common_cpu. This also works for "CPU".
+			 */
+			if (field && field->filter_type == FILTER_CPU) {
+				*flags |= HIST_FIELD_FL_CPU;
+			} else {
+				hist_err(tr, HIST_ERR_FIELD_NOT_FOUND,
+					 errpos(field_name));
+				field = ERR_PTR(-EINVAL);
+				goto out;
+			}
+		}
+	}
+ out:
+	kfree(str);
+
+	return field;
+}
+
+static struct hist_field *create_alias(struct hist_trigger_data *hist_data,
+				       struct hist_field *var_ref,
+				       char *var_name)
+{
+	struct hist_field *alias = NULL;
+	unsigned long flags = HIST_FIELD_FL_ALIAS | HIST_FIELD_FL_VAR;
+
+	alias = create_hist_field(hist_data, NULL, flags, var_name);
+	if (!alias)
+		return NULL;
+
+	alias->fn_num = var_ref->fn_num;
+	alias->operands[0] = var_ref;
+
+	if (init_var_ref(alias, var_ref, var_ref->system, var_ref->event_name)) {
+		destroy_hist_field(alias, 0);
+		return NULL;
+	}
+
+	alias->var_ref_idx = var_ref->var_ref_idx;
+
+	return alias;
+}
+
+static struct hist_field *parse_const(struct hist_trigger_data *hist_data,
+				      char *str, char *var_name,
+				      unsigned long *flags)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	struct hist_field *field = NULL;
+	u64 constant;
+
+	if (kstrtoull(str, 0, &constant)) {
+		hist_err(tr, HIST_ERR_EXPECT_NUMBER, errpos(str));
+		return NULL;
+	}
+
+	*flags |= HIST_FIELD_FL_CONST;
+	field = create_hist_field(hist_data, NULL, *flags, var_name);
+	if (!field)
+		return NULL;
+
+	field->constant = constant;
+
+	return field;
+}
+
+static struct hist_field *parse_atom(struct hist_trigger_data *hist_data,
+				     struct trace_event_file *file, char *str,
+				     unsigned long *flags, char *var_name)
+{
+	char *s, *ref_system = NULL, *ref_event = NULL, *ref_var = str;
+	struct ftrace_event_field *field = NULL;
+	struct hist_field *hist_field = NULL;
+	unsigned long buckets = 0;
+	int ret = 0;
+
+	if (isdigit(str[0])) {
+		hist_field = parse_const(hist_data, str, var_name, flags);
+		if (!hist_field) {
+			ret = -EINVAL;
+			goto out;
+		}
+		return hist_field;
+	}
+
+	s = strchr(str, '.');
+	if (s) {
+		s = strchr(++s, '.');
+		if (s) {
+			ref_system = strsep(&str, ".");
+			if (!str) {
+				ret = -EINVAL;
+				goto out;
+			}
+			ref_event = strsep(&str, ".");
+			if (!str) {
+				ret = -EINVAL;
+				goto out;
+			}
+			ref_var = str;
+		}
+	}
+
+	s = local_field_var_ref(hist_data, ref_system, ref_event, ref_var);
+	if (!s) {
+		hist_field = parse_var_ref(hist_data, ref_system,
+					   ref_event, ref_var);
+		if (hist_field) {
+			if (var_name) {
+				hist_field = create_alias(hist_data, hist_field, var_name);
+				if (!hist_field) {
+					ret = -ENOMEM;
+					goto out;
+				}
+			}
+			return hist_field;
+		}
+	} else
+		str = s;
+
+	field = parse_field(hist_data, file, str, flags, &buckets);
+	if (IS_ERR(field)) {
+		ret = PTR_ERR(field);
+		goto out;
+	}
+
+	hist_field = create_hist_field(hist_data, field, *flags, var_name);
+	if (!hist_field) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	hist_field->buckets = buckets;
+
+	return hist_field;
+ out:
+	return ERR_PTR(ret);
+}
+
+static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
+				     struct trace_event_file *file,
+				     char *str, unsigned long flags,
+				     char *var_name, unsigned int *n_subexprs);
+
+static struct hist_field *parse_unary(struct hist_trigger_data *hist_data,
+				      struct trace_event_file *file,
+				      char *str, unsigned long flags,
+				      char *var_name, unsigned int *n_subexprs)
+{
+	struct hist_field *operand1, *expr = NULL;
+	unsigned long operand_flags;
+	int ret = 0;
+	char *s;
+
+	/* Unary minus operator, increment n_subexprs */
+	++*n_subexprs;
+
+	/* we support only -(xxx) i.e. explicit parens required */
+
+	if (*n_subexprs > 3) {
+		hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
+		ret = -EINVAL;
+		goto free;
+	}
+
+	str++; /* skip leading '-' */
+
+	s = strchr(str, '(');
+	if (s)
+		str++;
+	else {
+		ret = -EINVAL;
+		goto free;
+	}
+
+	s = strrchr(str, ')');
+	if (s) {
+		 /* unary minus not supported in sub-expressions */
+		if (*(s+1) != '\0') {
+			hist_err(file->tr, HIST_ERR_UNARY_MINUS_SUBEXPR,
+				 errpos(str));
+			ret = -EINVAL;
+			goto free;
+		}
+		*s = '\0';
+	}
+	else {
+		ret = -EINVAL; /* no closing ')' */
+		goto free;
+	}
+
+	flags |= HIST_FIELD_FL_EXPR;
+	expr = create_hist_field(hist_data, NULL, flags, var_name);
+	if (!expr) {
+		ret = -ENOMEM;
+		goto free;
+	}
+
+	operand_flags = 0;
+	operand1 = parse_expr(hist_data, file, str, operand_flags, NULL, n_subexprs);
+	if (IS_ERR(operand1)) {
+		ret = PTR_ERR(operand1);
+		goto free;
+	}
+	if (operand1->flags & HIST_FIELD_FL_STRING) {
+		/* String type can not be the operand of unary operator. */
+		hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(str));
+		destroy_hist_field(operand1, 0);
+		ret = -EINVAL;
+		goto free;
+	}
+
+	expr->flags |= operand1->flags &
+		(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
+	expr->fn_num = HIST_FIELD_FN_UMINUS;
+	expr->operands[0] = operand1;
+	expr->size = operand1->size;
+	expr->is_signed = operand1->is_signed;
+	expr->operator = FIELD_OP_UNARY_MINUS;
+	expr->name = expr_str(expr, 0);
+	expr->type = kstrdup_const(operand1->type, GFP_KERNEL);
+	if (!expr->type) {
+		ret = -ENOMEM;
+		goto free;
+	}
+
+	return expr;
+ free:
+	destroy_hist_field(expr, 0);
+	return ERR_PTR(ret);
+}
+
+/*
+ * If the operands are var refs, return pointers the
+ * variable(s) referenced in var1 and var2, else NULL.
+ */
+static int check_expr_operands(struct trace_array *tr,
+			       struct hist_field *operand1,
+			       struct hist_field *operand2,
+			       struct hist_field **var1,
+			       struct hist_field **var2)
+{
+	unsigned long operand1_flags = operand1->flags;
+	unsigned long operand2_flags = operand2->flags;
+
+	if ((operand1_flags & HIST_FIELD_FL_VAR_REF) ||
+	    (operand1_flags & HIST_FIELD_FL_ALIAS)) {
+		struct hist_field *var;
+
+		var = find_var_field(operand1->var.hist_data, operand1->name);
+		if (!var)
+			return -EINVAL;
+		operand1_flags = var->flags;
+		*var1 = var;
+	}
+
+	if ((operand2_flags & HIST_FIELD_FL_VAR_REF) ||
+	    (operand2_flags & HIST_FIELD_FL_ALIAS)) {
+		struct hist_field *var;
+
+		var = find_var_field(operand2->var.hist_data, operand2->name);
+		if (!var)
+			return -EINVAL;
+		operand2_flags = var->flags;
+		*var2 = var;
+	}
+
+	if ((operand1_flags & HIST_FIELD_FL_TIMESTAMP_USECS) !=
+	    (operand2_flags & HIST_FIELD_FL_TIMESTAMP_USECS)) {
+		hist_err(tr, HIST_ERR_TIMESTAMP_MISMATCH, 0);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
+				     struct trace_event_file *file,
+				     char *str, unsigned long flags,
+				     char *var_name, unsigned int *n_subexprs)
+{
+	struct hist_field *operand1 = NULL, *operand2 = NULL, *expr = NULL;
+	struct hist_field *var1 = NULL, *var2 = NULL;
+	unsigned long operand_flags, operand2_flags;
+	int field_op, ret = -EINVAL;
+	char *sep, *operand1_str;
+	enum hist_field_fn op_fn;
+	bool combine_consts;
+
+	if (*n_subexprs > 3) {
+		hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
+		return ERR_PTR(-EINVAL);
+	}
+
+	field_op = contains_operator(str, &sep);
+
+	if (field_op == FIELD_OP_NONE)
+		return parse_atom(hist_data, file, str, &flags, var_name);
+
+	if (field_op == FIELD_OP_UNARY_MINUS)
+		return parse_unary(hist_data, file, str, flags, var_name, n_subexprs);
+
+	/* Binary operator found, increment n_subexprs */
+	++*n_subexprs;
+
+	/* Split the expression string at the root operator */
+	if (!sep)
+		return ERR_PTR(-EINVAL);
+
+	*sep = '\0';
+	operand1_str = str;
+	str = sep+1;
+
+	/* Binary operator requires both operands */
+	if (*operand1_str == '\0' || *str == '\0')
+		return ERR_PTR(-EINVAL);
+
+	operand_flags = 0;
+
+	/* LHS of string is an expression e.g. a+b in a+b+c */
+	operand1 = parse_expr(hist_data, file, operand1_str, operand_flags, NULL, n_subexprs);
+	if (IS_ERR(operand1))
+		return ERR_CAST(operand1);
+
+	if (operand1->flags & HIST_FIELD_FL_STRING) {
+		hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(operand1_str));
+		ret = -EINVAL;
+		goto free_op1;
+	}
+
+	/* RHS of string is another expression e.g. c in a+b+c */
+	operand_flags = 0;
+	operand2 = parse_expr(hist_data, file, str, operand_flags, NULL, n_subexprs);
+	if (IS_ERR(operand2)) {
+		ret = PTR_ERR(operand2);
+		goto free_op1;
+	}
+	if (operand2->flags & HIST_FIELD_FL_STRING) {
+		hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(str));
+		ret = -EINVAL;
+		goto free_operands;
+	}
+
+	switch (field_op) {
+	case FIELD_OP_MINUS:
+		op_fn = HIST_FIELD_FN_MINUS;
+		break;
+	case FIELD_OP_PLUS:
+		op_fn = HIST_FIELD_FN_PLUS;
+		break;
+	case FIELD_OP_DIV:
+		op_fn = HIST_FIELD_FN_DIV;
+		break;
+	case FIELD_OP_MULT:
+		op_fn = HIST_FIELD_FN_MULT;
+		break;
+	default:
+		ret = -EINVAL;
+		goto free_operands;
+	}
+
+	ret = check_expr_operands(file->tr, operand1, operand2, &var1, &var2);
+	if (ret)
+		goto free_operands;
+
+	operand_flags = var1 ? var1->flags : operand1->flags;
+	operand2_flags = var2 ? var2->flags : operand2->flags;
+
+	/*
+	 * If both operands are constant, the expression can be
+	 * collapsed to a single constant.
+	 */
+	combine_consts = operand_flags & operand2_flags & HIST_FIELD_FL_CONST;
+
+	flags |= combine_consts ? HIST_FIELD_FL_CONST : HIST_FIELD_FL_EXPR;
+
+	flags |= operand1->flags &
+		(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
+
+	expr = create_hist_field(hist_data, NULL, flags, var_name);
+	if (!expr) {
+		ret = -ENOMEM;
+		goto free_operands;
+	}
+
+	operand1->read_once = true;
+	operand2->read_once = true;
+
+	/* The operands are now owned and free'd by 'expr' */
+	expr->operands[0] = operand1;
+	expr->operands[1] = operand2;
+
+	if (field_op == FIELD_OP_DIV &&
+			operand2_flags & HIST_FIELD_FL_CONST) {
+		u64 divisor = var2 ? var2->constant : operand2->constant;
+
+		if (!divisor) {
+			hist_err(file->tr, HIST_ERR_DIVISION_BY_ZERO, errpos(str));
+			ret = -EDOM;
+			goto free_expr;
+		}
+
+		/*
+		 * Copy the divisor here so we don't have to look it up
+		 * later if this is a var ref
+		 */
+		operand2->constant = divisor;
+		op_fn = hist_field_get_div_fn(operand2);
+	}
+
+	expr->fn_num = op_fn;
+
+	if (combine_consts) {
+		if (var1)
+			expr->operands[0] = var1;
+		if (var2)
+			expr->operands[1] = var2;
+
+		expr->constant = hist_fn_call(expr, NULL, NULL, NULL, NULL);
+		expr->fn_num = HIST_FIELD_FN_CONST;
+
+		expr->operands[0] = NULL;
+		expr->operands[1] = NULL;
+
+		/*
+		 * var refs won't be destroyed immediately
+		 * See: destroy_hist_field()
+		 */
+		destroy_hist_field(operand2, 0);
+		destroy_hist_field(operand1, 0);
+
+		expr->name = expr_str(expr, 0);
+	} else {
+		/* The operand sizes should be the same, so just pick one */
+		expr->size = operand1->size;
+		expr->is_signed = operand1->is_signed;
+
+		expr->operator = field_op;
+		expr->type = kstrdup_const(operand1->type, GFP_KERNEL);
+		if (!expr->type) {
+			ret = -ENOMEM;
+			goto free_expr;
+		}
+
+		expr->name = expr_str(expr, 0);
+	}
+
+	return expr;
+
+free_operands:
+	destroy_hist_field(operand2, 0);
+free_op1:
+	destroy_hist_field(operand1, 0);
+	return ERR_PTR(ret);
+
+free_expr:
+	destroy_hist_field(expr, 0);
+	return ERR_PTR(ret);
+}
+
+static char *find_trigger_filter(struct hist_trigger_data *hist_data,
+				 struct trace_event_file *file)
+{
+	struct event_trigger_data *test;
+
+	lockdep_assert_held(&event_mutex);
+
+	list_for_each_entry(test, &file->triggers, list) {
+		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+			if (test->private_data == hist_data)
+				return test->filter_str;
+		}
+	}
+
+	return NULL;
+}
+
+static struct event_command trigger_hist_cmd;
+static int event_hist_trigger_parse(struct event_command *cmd_ops,
+				    struct trace_event_file *file,
+				    char *glob, char *cmd,
+				    char *param_and_filter);
+
+static bool compatible_keys(struct hist_trigger_data *target_hist_data,
+			    struct hist_trigger_data *hist_data,
+			    unsigned int n_keys)
+{
+	struct hist_field *target_hist_field, *hist_field;
+	unsigned int n, i, j;
+
+	if (hist_data->n_fields - hist_data->n_vals != n_keys)
+		return false;
+
+	i = hist_data->n_vals;
+	j = target_hist_data->n_vals;
+
+	for (n = 0; n < n_keys; n++) {
+		hist_field = hist_data->fields[i + n];
+		target_hist_field = target_hist_data->fields[j + n];
+
+		if (strcmp(hist_field->type, target_hist_field->type) != 0)
+			return false;
+		if (hist_field->size != target_hist_field->size)
+			return false;
+		if (hist_field->is_signed != target_hist_field->is_signed)
+			return false;
+	}
+
+	return true;
+}
+
+static struct hist_trigger_data *
+find_compatible_hist(struct hist_trigger_data *target_hist_data,
+		     struct trace_event_file *file)
+{
+	struct hist_trigger_data *hist_data;
+	struct event_trigger_data *test;
+	unsigned int n_keys;
+
+	lockdep_assert_held(&event_mutex);
+
+	n_keys = target_hist_data->n_fields - target_hist_data->n_vals;
+
+	list_for_each_entry(test, &file->triggers, list) {
+		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+			hist_data = test->private_data;
+
+			if (compatible_keys(target_hist_data, hist_data, n_keys))
+				return hist_data;
+		}
+	}
+
+	return NULL;
+}
+
+static struct trace_event_file *event_file(struct trace_array *tr,
+					   char *system, char *event_name)
+{
+	struct trace_event_file *file;
+
+	file = __find_event_file(tr, system, event_name);
+	if (!file)
+		return ERR_PTR(-EINVAL);
+
+	return file;
+}
+
+static struct hist_field *
+find_synthetic_field_var(struct hist_trigger_data *target_hist_data,
+			 char *system, char *event_name, char *field_name)
+{
+	struct hist_field *event_var;
+	char *synthetic_name;
+
+	synthetic_name = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
+	if (!synthetic_name)
+		return ERR_PTR(-ENOMEM);
+
+	strcpy(synthetic_name, "synthetic_");
+	strcat(synthetic_name, field_name);
+
+	event_var = find_event_var(target_hist_data, system, event_name, synthetic_name);
+
+	kfree(synthetic_name);
+
+	return event_var;
+}
+
+/**
+ * create_field_var_hist - Automatically create a histogram and var for a field
+ * @target_hist_data: The target hist trigger
+ * @subsys_name: Optional subsystem name
+ * @event_name: Optional event name
+ * @field_name: The name of the field (and the resulting variable)
+ *
+ * Hist trigger actions fetch data from variables, not directly from
+ * events.  However, for convenience, users are allowed to directly
+ * specify an event field in an action, which will be automatically
+ * converted into a variable on their behalf.
+ *
+ * If a user specifies a field on an event that isn't the event the
+ * histogram currently being defined (the target event histogram), the
+ * only way that can be accomplished is if a new hist trigger is
+ * created and the field variable defined on that.
+ *
+ * This function creates a new histogram compatible with the target
+ * event (meaning a histogram with the same key as the target
+ * histogram), and creates a variable for the specified field, but
+ * with 'synthetic_' prepended to the variable name in order to avoid
+ * collision with normal field variables.
+ *
+ * Return: The variable created for the field.
+ */
+static struct hist_field *
+create_field_var_hist(struct hist_trigger_data *target_hist_data,
+		      char *subsys_name, char *event_name, char *field_name)
+{
+	struct trace_array *tr = target_hist_data->event_file->tr;
+	struct hist_trigger_data *hist_data;
+	unsigned int i, n, first = true;
+	struct field_var_hist *var_hist;
+	struct trace_event_file *file;
+	struct hist_field *key_field;
+	struct hist_field *event_var;
+	char *saved_filter;
+	char *cmd;
+	int ret;
+
+	if (target_hist_data->n_field_var_hists >= SYNTH_FIELDS_MAX) {
+		hist_err(tr, HIST_ERR_TOO_MANY_FIELD_VARS, errpos(field_name));
+		return ERR_PTR(-EINVAL);
+	}
+
+	file = event_file(tr, subsys_name, event_name);
+
+	if (IS_ERR(file)) {
+		hist_err(tr, HIST_ERR_EVENT_FILE_NOT_FOUND, errpos(field_name));
+		ret = PTR_ERR(file);
+		return ERR_PTR(ret);
+	}
+
+	/*
+	 * Look for a histogram compatible with target.  We'll use the
+	 * found histogram specification to create a new matching
+	 * histogram with our variable on it.  target_hist_data is not
+	 * yet a registered histogram so we can't use that.
+	 */
+	hist_data = find_compatible_hist(target_hist_data, file);
+	if (!hist_data) {
+		hist_err(tr, HIST_ERR_HIST_NOT_FOUND, errpos(field_name));
+		return ERR_PTR(-EINVAL);
+	}
+
+	/* See if a synthetic field variable has already been created */
+	event_var = find_synthetic_field_var(target_hist_data, subsys_name,
+					     event_name, field_name);
+	if (!IS_ERR_OR_NULL(event_var))
+		return event_var;
+
+	var_hist = kzalloc(sizeof(*var_hist), GFP_KERNEL);
+	if (!var_hist)
+		return ERR_PTR(-ENOMEM);
+
+	cmd = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
+	if (!cmd) {
+		kfree(var_hist);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/* Use the same keys as the compatible histogram */
+	strcat(cmd, "keys=");
+
+	for_each_hist_key_field(i, hist_data) {
+		key_field = hist_data->fields[i];
+		if (!first)
+			strcat(cmd, ",");
+		strcat(cmd, key_field->field->name);
+		first = false;
+	}
+
+	/* Create the synthetic field variable specification */
+	strcat(cmd, ":synthetic_");
+	strcat(cmd, field_name);
+	strcat(cmd, "=");
+	strcat(cmd, field_name);
+
+	/* Use the same filter as the compatible histogram */
+	saved_filter = find_trigger_filter(hist_data, file);
+	if (saved_filter) {
+		strcat(cmd, " if ");
+		strcat(cmd, saved_filter);
+	}
+
+	var_hist->cmd = kstrdup(cmd, GFP_KERNEL);
+	if (!var_hist->cmd) {
+		kfree(cmd);
+		kfree(var_hist);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/* Save the compatible histogram information */
+	var_hist->hist_data = hist_data;
+
+	/* Create the new histogram with our variable */
+	ret = event_hist_trigger_parse(&trigger_hist_cmd, file,
+				       "", "hist", cmd);
+	if (ret) {
+		kfree(cmd);
+		kfree(var_hist->cmd);
+		kfree(var_hist);
+		hist_err(tr, HIST_ERR_HIST_CREATE_FAIL, errpos(field_name));
+		return ERR_PTR(ret);
+	}
+
+	kfree(cmd);
+
+	/* If we can't find the variable, something went wrong */
+	event_var = find_synthetic_field_var(target_hist_data, subsys_name,
+					     event_name, field_name);
+	if (IS_ERR_OR_NULL(event_var)) {
+		kfree(var_hist->cmd);
+		kfree(var_hist);
+		hist_err(tr, HIST_ERR_SYNTH_VAR_NOT_FOUND, errpos(field_name));
+		return ERR_PTR(-EINVAL);
+	}
+
+	n = target_hist_data->n_field_var_hists;
+	target_hist_data->field_var_hists[n] = var_hist;
+	target_hist_data->n_field_var_hists++;
+
+	return event_var;
+}
+
+static struct hist_field *
+find_target_event_var(struct hist_trigger_data *hist_data,
+		      char *subsys_name, char *event_name, char *var_name)
+{
+	struct trace_event_file *file = hist_data->event_file;
+	struct hist_field *hist_field = NULL;
+
+	if (subsys_name) {
+		struct trace_event_call *call;
+
+		if (!event_name)
+			return NULL;
+
+		call = file->event_call;
+
+		if (strcmp(subsys_name, call->class->system) != 0)
+			return NULL;
+
+		if (strcmp(event_name, trace_event_name(call)) != 0)
+			return NULL;
+	}
+
+	hist_field = find_var_field(hist_data, var_name);
+
+	return hist_field;
+}
+
+static inline void __update_field_vars(struct tracing_map_elt *elt,
+				       struct trace_buffer *buffer,
+				       struct ring_buffer_event *rbe,
+				       void *rec,
+				       struct field_var **field_vars,
+				       unsigned int n_field_vars,
+				       unsigned int field_var_str_start)
+{
+	struct hist_elt_data *elt_data = elt->private_data;
+	unsigned int i, j, var_idx;
+	u64 var_val;
+
+	for (i = 0, j = field_var_str_start; i < n_field_vars; i++) {
+		struct field_var *field_var = field_vars[i];
+		struct hist_field *var = field_var->var;
+		struct hist_field *val = field_var->val;
+
+		var_val = hist_fn_call(val, elt, buffer, rbe, rec);
+		var_idx = var->var.idx;
+
+		if (val->flags & HIST_FIELD_FL_STRING) {
+			char *str = elt_data->field_var_str[j++];
+			char *val_str = (char *)(uintptr_t)var_val;
+			unsigned int size;
+
+			size = min(val->size, STR_VAR_LEN_MAX);
+			strscpy(str, val_str, size);
+			var_val = (u64)(uintptr_t)str;
+		}
+		tracing_map_set_var(elt, var_idx, var_val);
+	}
+}
+
+static void update_field_vars(struct hist_trigger_data *hist_data,
+			      struct tracing_map_elt *elt,
+			      struct trace_buffer *buffer,
+			      struct ring_buffer_event *rbe,
+			      void *rec)
+{
+	__update_field_vars(elt, buffer, rbe, rec, hist_data->field_vars,
+			    hist_data->n_field_vars, 0);
+}
+
+static void save_track_data_vars(struct hist_trigger_data *hist_data,
+				 struct tracing_map_elt *elt,
+				 struct trace_buffer *buffer,  void *rec,
+				 struct ring_buffer_event *rbe, void *key,
+				 struct action_data *data, u64 *var_ref_vals)
+{
+	__update_field_vars(elt, buffer, rbe, rec, hist_data->save_vars,
+			    hist_data->n_save_vars, hist_data->n_field_var_str);
+}
+
+static struct hist_field *create_var(struct hist_trigger_data *hist_data,
+				     struct trace_event_file *file,
+				     char *name, int size, const char *type)
+{
+	struct hist_field *var;
+	int idx;
+
+	if (find_var(hist_data, file, name) && !hist_data->remove) {
+		var = ERR_PTR(-EINVAL);
+		goto out;
+	}
+
+	var = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
+	if (!var) {
+		var = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	idx = tracing_map_add_var(hist_data->map);
+	if (idx < 0) {
+		kfree(var);
+		var = ERR_PTR(-EINVAL);
+		goto out;
+	}
+
+	var->ref = 1;
+	var->flags = HIST_FIELD_FL_VAR;
+	var->var.idx = idx;
+	var->var.hist_data = var->hist_data = hist_data;
+	var->size = size;
+	var->var.name = kstrdup(name, GFP_KERNEL);
+	var->type = kstrdup_const(type, GFP_KERNEL);
+	if (!var->var.name || !var->type) {
+		kfree_const(var->type);
+		kfree(var->var.name);
+		kfree(var);
+		var = ERR_PTR(-ENOMEM);
+	}
+ out:
+	return var;
+}
+
+static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
+					  struct trace_event_file *file,
+					  char *field_name)
+{
+	struct hist_field *val = NULL, *var = NULL;
+	unsigned long flags = HIST_FIELD_FL_VAR;
+	struct trace_array *tr = file->tr;
+	struct field_var *field_var;
+	int ret = 0;
+
+	if (hist_data->n_field_vars >= SYNTH_FIELDS_MAX) {
+		hist_err(tr, HIST_ERR_TOO_MANY_FIELD_VARS, errpos(field_name));
+		ret = -EINVAL;
+		goto err;
+	}
+
+	val = parse_atom(hist_data, file, field_name, &flags, NULL);
+	if (IS_ERR(val)) {
+		hist_err(tr, HIST_ERR_FIELD_VAR_PARSE_FAIL, errpos(field_name));
+		ret = PTR_ERR(val);
+		goto err;
+	}
+
+	var = create_var(hist_data, file, field_name, val->size, val->type);
+	if (IS_ERR(var)) {
+		hist_err(tr, HIST_ERR_VAR_CREATE_FIND_FAIL, errpos(field_name));
+		kfree(val);
+		ret = PTR_ERR(var);
+		goto err;
+	}
+
+	field_var = kzalloc(sizeof(struct field_var), GFP_KERNEL);
+	if (!field_var) {
+		kfree(val);
+		kfree(var);
+		ret =  -ENOMEM;
+		goto err;
+	}
+
+	field_var->var = var;
+	field_var->val = val;
+ out:
+	return field_var;
+ err:
+	field_var = ERR_PTR(ret);
+	goto out;
+}
+
+/**
+ * create_target_field_var - Automatically create a variable for a field
+ * @target_hist_data: The target hist trigger
+ * @subsys_name: Optional subsystem name
+ * @event_name: Optional event name
+ * @var_name: The name of the field (and the resulting variable)
+ *
+ * Hist trigger actions fetch data from variables, not directly from
+ * events.  However, for convenience, users are allowed to directly
+ * specify an event field in an action, which will be automatically
+ * converted into a variable on their behalf.
+ *
+ * This function creates a field variable with the name var_name on
+ * the hist trigger currently being defined on the target event.  If
+ * subsys_name and event_name are specified, this function simply
+ * verifies that they do in fact match the target event subsystem and
+ * event name.
+ *
+ * Return: The variable created for the field.
+ */
+static struct field_var *
+create_target_field_var(struct hist_trigger_data *target_hist_data,
+			char *subsys_name, char *event_name, char *var_name)
+{
+	struct trace_event_file *file = target_hist_data->event_file;
+
+	if (subsys_name) {
+		struct trace_event_call *call;
+
+		if (!event_name)
+			return NULL;
+
+		call = file->event_call;
+
+		if (strcmp(subsys_name, call->class->system) != 0)
+			return NULL;
+
+		if (strcmp(event_name, trace_event_name(call)) != 0)
+			return NULL;
+	}
+
+	return create_field_var(target_hist_data, file, var_name);
+}
+
+static bool check_track_val_max(u64 track_val, u64 var_val)
+{
+	if (var_val <= track_val)
+		return false;
+
+	return true;
+}
+
+static bool check_track_val_changed(u64 track_val, u64 var_val)
+{
+	if (var_val == track_val)
+		return false;
+
+	return true;
+}
+
+static u64 get_track_val(struct hist_trigger_data *hist_data,
+			 struct tracing_map_elt *elt,
+			 struct action_data *data)
+{
+	unsigned int track_var_idx = data->track_data.track_var->var.idx;
+	u64 track_val;
+
+	track_val = tracing_map_read_var(elt, track_var_idx);
+
+	return track_val;
+}
+
+static void save_track_val(struct hist_trigger_data *hist_data,
+			   struct tracing_map_elt *elt,
+			   struct action_data *data, u64 var_val)
+{
+	unsigned int track_var_idx = data->track_data.track_var->var.idx;
+
+	tracing_map_set_var(elt, track_var_idx, var_val);
+}
+
+static void save_track_data(struct hist_trigger_data *hist_data,
+			    struct tracing_map_elt *elt,
+			    struct trace_buffer *buffer, void *rec,
+			    struct ring_buffer_event *rbe, void *key,
+			    struct action_data *data, u64 *var_ref_vals)
+{
+	if (data->track_data.save_data)
+		data->track_data.save_data(hist_data, elt, buffer, rec, rbe,
+					   key, data, var_ref_vals);
+}
+
+static bool check_track_val(struct tracing_map_elt *elt,
+			    struct action_data *data,
+			    u64 var_val)
+{
+	struct hist_trigger_data *hist_data;
+	u64 track_val;
+
+	hist_data = data->track_data.track_var->hist_data;
+	track_val = get_track_val(hist_data, elt, data);
+
+	return data->track_data.check_val(track_val, var_val);
+}
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
+{
+	/* called with tr->max_lock held */
+	struct track_data *track_data = tr->cond_snapshot->cond_data;
+	struct hist_elt_data *elt_data, *track_elt_data;
+	struct snapshot_context *context = cond_data;
+	struct action_data *action;
+	u64 track_val;
+
+	if (!track_data)
+		return false;
+
+	action = track_data->action_data;
+
+	track_val = get_track_val(track_data->hist_data, context->elt,
+				  track_data->action_data);
+
+	if (!action->track_data.check_val(track_data->track_val, track_val))
+		return false;
+
+	track_data->track_val = track_val;
+	memcpy(track_data->key, context->key, track_data->key_len);
+
+	elt_data = context->elt->private_data;
+	track_elt_data = track_data->elt.private_data;
+	if (elt_data->comm)
+		strncpy(track_elt_data->comm, elt_data->comm, TASK_COMM_LEN);
+
+	track_data->updated = true;
+
+	return true;
+}
+
+static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
+				     struct tracing_map_elt *elt,
+				     struct trace_buffer *buffer, void *rec,
+				     struct ring_buffer_event *rbe, void *key,
+				     struct action_data *data,
+				     u64 *var_ref_vals)
+{
+	struct trace_event_file *file = hist_data->event_file;
+	struct snapshot_context context;
+
+	context.elt = elt;
+	context.key = key;
+
+	tracing_snapshot_cond(file->tr, &context);
+}
+
+static void hist_trigger_print_key(struct seq_file *m,
+				   struct hist_trigger_data *hist_data,
+				   void *key,
+				   struct tracing_map_elt *elt);
+
+static struct action_data *snapshot_action(struct hist_trigger_data *hist_data)
+{
+	unsigned int i;
+
+	if (!hist_data->n_actions)
+		return NULL;
+
+	for (i = 0; i < hist_data->n_actions; i++) {
+		struct action_data *data = hist_data->actions[i];
+
+		if (data->action == ACTION_SNAPSHOT)
+			return data;
+	}
+
+	return NULL;
+}
+
+static void track_data_snapshot_print(struct seq_file *m,
+				      struct hist_trigger_data *hist_data)
+{
+	struct trace_event_file *file = hist_data->event_file;
+	struct track_data *track_data;
+	struct action_data *action;
+
+	track_data = tracing_cond_snapshot_data(file->tr);
+	if (!track_data)
+		return;
+
+	if (!track_data->updated)
+		return;
+
+	action = snapshot_action(hist_data);
+	if (!action)
+		return;
+
+	seq_puts(m, "\nSnapshot taken (see tracing/snapshot).  Details:\n");
+	seq_printf(m, "\ttriggering value { %s(%s) }: %10llu",
+		   action->handler == HANDLER_ONMAX ? "onmax" : "onchange",
+		   action->track_data.var_str, track_data->track_val);
+
+	seq_puts(m, "\ttriggered by event with key: ");
+	hist_trigger_print_key(m, hist_data, track_data->key, &track_data->elt);
+	seq_putc(m, '\n');
+}
+#else
+static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
+{
+	return false;
+}
+static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
+				     struct tracing_map_elt *elt,
+				     struct trace_buffer *buffer, void *rec,
+				     struct ring_buffer_event *rbe, void *key,
+				     struct action_data *data,
+				     u64 *var_ref_vals) {}
+static void track_data_snapshot_print(struct seq_file *m,
+				      struct hist_trigger_data *hist_data) {}
+#endif /* CONFIG_TRACER_SNAPSHOT */
+
+static void track_data_print(struct seq_file *m,
+			     struct hist_trigger_data *hist_data,
+			     struct tracing_map_elt *elt,
+			     struct action_data *data)
+{
+	u64 track_val = get_track_val(hist_data, elt, data);
+	unsigned int i, save_var_idx;
+
+	if (data->handler == HANDLER_ONMAX)
+		seq_printf(m, "\n\tmax: %10llu", track_val);
+	else if (data->handler == HANDLER_ONCHANGE)
+		seq_printf(m, "\n\tchanged: %10llu", track_val);
+
+	if (data->action == ACTION_SNAPSHOT)
+		return;
+
+	for (i = 0; i < hist_data->n_save_vars; i++) {
+		struct hist_field *save_val = hist_data->save_vars[i]->val;
+		struct hist_field *save_var = hist_data->save_vars[i]->var;
+		u64 val;
+
+		save_var_idx = save_var->var.idx;
+
+		val = tracing_map_read_var(elt, save_var_idx);
+
+		if (save_val->flags & HIST_FIELD_FL_STRING) {
+			seq_printf(m, "  %s: %-32s", save_var->var.name,
+				   (char *)(uintptr_t)(val));
+		} else
+			seq_printf(m, "  %s: %10llu", save_var->var.name, val);
+	}
+}
+
+static void ontrack_action(struct hist_trigger_data *hist_data,
+			   struct tracing_map_elt *elt,
+			   struct trace_buffer *buffer, void *rec,
+			   struct ring_buffer_event *rbe, void *key,
+			   struct action_data *data, u64 *var_ref_vals)
+{
+	u64 var_val = var_ref_vals[data->track_data.var_ref->var_ref_idx];
+
+	if (check_track_val(elt, data, var_val)) {
+		save_track_val(hist_data, elt, data, var_val);
+		save_track_data(hist_data, elt, buffer, rec, rbe,
+				key, data, var_ref_vals);
+	}
+}
+
+static void action_data_destroy(struct action_data *data)
+{
+	unsigned int i;
+
+	lockdep_assert_held(&event_mutex);
+
+	kfree(data->action_name);
+
+	for (i = 0; i < data->n_params; i++)
+		kfree(data->params[i]);
+
+	if (data->synth_event)
+		data->synth_event->ref--;
+
+	kfree(data->synth_event_name);
+
+	kfree(data);
+}
+
+static void track_data_destroy(struct hist_trigger_data *hist_data,
+			       struct action_data *data)
+{
+	struct trace_event_file *file = hist_data->event_file;
+
+	destroy_hist_field(data->track_data.track_var, 0);
+
+	if (data->action == ACTION_SNAPSHOT) {
+		struct track_data *track_data;
+
+		track_data = tracing_cond_snapshot_data(file->tr);
+		if (track_data && track_data->hist_data == hist_data) {
+			tracing_snapshot_cond_disable(file->tr);
+			track_data_free(track_data);
+		}
+	}
+
+	kfree(data->track_data.var_str);
+
+	action_data_destroy(data);
+}
+
+static int action_create(struct hist_trigger_data *hist_data,
+			 struct action_data *data);
+
+static int track_data_create(struct hist_trigger_data *hist_data,
+			     struct action_data *data)
+{
+	struct hist_field *var_field, *ref_field, *track_var = NULL;
+	struct trace_event_file *file = hist_data->event_file;
+	struct trace_array *tr = file->tr;
+	char *track_data_var_str;
+	int ret = 0;
+
+	track_data_var_str = data->track_data.var_str;
+	if (track_data_var_str[0] != '$') {
+		hist_err(tr, HIST_ERR_ONX_NOT_VAR, errpos(track_data_var_str));
+		return -EINVAL;
+	}
+	track_data_var_str++;
+
+	var_field = find_target_event_var(hist_data, NULL, NULL, track_data_var_str);
+	if (!var_field) {
+		hist_err(tr, HIST_ERR_ONX_VAR_NOT_FOUND, errpos(track_data_var_str));
+		return -EINVAL;
+	}
+
+	ref_field = create_var_ref(hist_data, var_field, NULL, NULL);
+	if (!ref_field)
+		return -ENOMEM;
+
+	data->track_data.var_ref = ref_field;
+
+	if (data->handler == HANDLER_ONMAX)
+		track_var = create_var(hist_data, file, "__max", sizeof(u64), "u64");
+	if (IS_ERR(track_var)) {
+		hist_err(tr, HIST_ERR_ONX_VAR_CREATE_FAIL, 0);
+		ret = PTR_ERR(track_var);
+		goto out;
+	}
+
+	if (data->handler == HANDLER_ONCHANGE)
+		track_var = create_var(hist_data, file, "__change", sizeof(u64), "u64");
+	if (IS_ERR(track_var)) {
+		hist_err(tr, HIST_ERR_ONX_VAR_CREATE_FAIL, 0);
+		ret = PTR_ERR(track_var);
+		goto out;
+	}
+	data->track_data.track_var = track_var;
+
+	ret = action_create(hist_data, data);
+ out:
+	return ret;
+}
+
+static int parse_action_params(struct trace_array *tr, char *params,
+			       struct action_data *data)
+{
+	char *param, *saved_param;
+	bool first_param = true;
+	int ret = 0;
+
+	while (params) {
+		if (data->n_params >= SYNTH_FIELDS_MAX) {
+			hist_err(tr, HIST_ERR_TOO_MANY_PARAMS, 0);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		param = strsep(&params, ",");
+		if (!param) {
+			hist_err(tr, HIST_ERR_PARAM_NOT_FOUND, 0);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		param = strstrip(param);
+		if (strlen(param) < 2) {
+			hist_err(tr, HIST_ERR_INVALID_PARAM, errpos(param));
+			ret = -EINVAL;
+			goto out;
+		}
+
+		saved_param = kstrdup(param, GFP_KERNEL);
+		if (!saved_param) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		if (first_param && data->use_trace_keyword) {
+			data->synth_event_name = saved_param;
+			first_param = false;
+			continue;
+		}
+		first_param = false;
+
+		data->params[data->n_params++] = saved_param;
+	}
+ out:
+	return ret;
+}
+
+static int action_parse(struct trace_array *tr, char *str, struct action_data *data,
+			enum handler_id handler)
+{
+	char *action_name;
+	int ret = 0;
+
+	strsep(&str, ".");
+	if (!str) {
+		hist_err(tr, HIST_ERR_ACTION_NOT_FOUND, 0);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	action_name = strsep(&str, "(");
+	if (!action_name || !str) {
+		hist_err(tr, HIST_ERR_ACTION_NOT_FOUND, 0);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (str_has_prefix(action_name, "save")) {
+		char *params = strsep(&str, ")");
+
+		if (!params) {
+			hist_err(tr, HIST_ERR_NO_SAVE_PARAMS, 0);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		ret = parse_action_params(tr, params, data);
+		if (ret)
+			goto out;
+
+		if (handler == HANDLER_ONMAX)
+			data->track_data.check_val = check_track_val_max;
+		else if (handler == HANDLER_ONCHANGE)
+			data->track_data.check_val = check_track_val_changed;
+		else {
+			hist_err(tr, HIST_ERR_ACTION_MISMATCH, errpos(action_name));
+			ret = -EINVAL;
+			goto out;
+		}
+
+		data->track_data.save_data = save_track_data_vars;
+		data->fn = ontrack_action;
+		data->action = ACTION_SAVE;
+	} else if (str_has_prefix(action_name, "snapshot")) {
+		char *params = strsep(&str, ")");
+
+		if (!str) {
+			hist_err(tr, HIST_ERR_NO_CLOSING_PAREN, errpos(params));
+			ret = -EINVAL;
+			goto out;
+		}
+
+		if (handler == HANDLER_ONMAX)
+			data->track_data.check_val = check_track_val_max;
+		else if (handler == HANDLER_ONCHANGE)
+			data->track_data.check_val = check_track_val_changed;
+		else {
+			hist_err(tr, HIST_ERR_ACTION_MISMATCH, errpos(action_name));
+			ret = -EINVAL;
+			goto out;
+		}
+
+		data->track_data.save_data = save_track_data_snapshot;
+		data->fn = ontrack_action;
+		data->action = ACTION_SNAPSHOT;
+	} else {
+		char *params = strsep(&str, ")");
+
+		if (str_has_prefix(action_name, "trace"))
+			data->use_trace_keyword = true;
+
+		if (params) {
+			ret = parse_action_params(tr, params, data);
+			if (ret)
+				goto out;
+		}
+
+		if (handler == HANDLER_ONMAX)
+			data->track_data.check_val = check_track_val_max;
+		else if (handler == HANDLER_ONCHANGE)
+			data->track_data.check_val = check_track_val_changed;
+
+		if (handler != HANDLER_ONMATCH) {
+			data->track_data.save_data = action_trace;
+			data->fn = ontrack_action;
+		} else
+			data->fn = action_trace;
+
+		data->action = ACTION_TRACE;
+	}
+
+	data->action_name = kstrdup(action_name, GFP_KERNEL);
+	if (!data->action_name) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	data->handler = handler;
+ out:
+	return ret;
+}
+
+static struct action_data *track_data_parse(struct hist_trigger_data *hist_data,
+					    char *str, enum handler_id handler)
+{
+	struct action_data *data;
+	int ret = -EINVAL;
+	char *var_str;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return ERR_PTR(-ENOMEM);
+
+	var_str = strsep(&str, ")");
+	if (!var_str || !str) {
+		ret = -EINVAL;
+		goto free;
+	}
+
+	data->track_data.var_str = kstrdup(var_str, GFP_KERNEL);
+	if (!data->track_data.var_str) {
+		ret = -ENOMEM;
+		goto free;
+	}
+
+	ret = action_parse(hist_data->event_file->tr, str, data, handler);
+	if (ret)
+		goto free;
+ out:
+	return data;
+ free:
+	track_data_destroy(hist_data, data);
+	data = ERR_PTR(ret);
+	goto out;
+}
+
+static void onmatch_destroy(struct action_data *data)
+{
+	kfree(data->match_data.event);
+	kfree(data->match_data.event_system);
+
+	action_data_destroy(data);
+}
+
+static void destroy_field_var(struct field_var *field_var)
+{
+	if (!field_var)
+		return;
+
+	destroy_hist_field(field_var->var, 0);
+	destroy_hist_field(field_var->val, 0);
+
+	kfree(field_var);
+}
+
+static void destroy_field_vars(struct hist_trigger_data *hist_data)
+{
+	unsigned int i;
+
+	for (i = 0; i < hist_data->n_field_vars; i++)
+		destroy_field_var(hist_data->field_vars[i]);
+
+	for (i = 0; i < hist_data->n_save_vars; i++)
+		destroy_field_var(hist_data->save_vars[i]);
+}
+
+static void save_field_var(struct hist_trigger_data *hist_data,
+			   struct field_var *field_var)
+{
+	hist_data->field_vars[hist_data->n_field_vars++] = field_var;
+
+	if (field_var->val->flags & HIST_FIELD_FL_STRING)
+		hist_data->n_field_var_str++;
+}
+
+
+static int check_synth_field(struct synth_event *event,
+			     struct hist_field *hist_field,
+			     unsigned int field_pos)
+{
+	struct synth_field *field;
+
+	if (field_pos >= event->n_fields)
+		return -EINVAL;
+
+	field = event->fields[field_pos];
+
+	/*
+	 * A dynamic string synth field can accept static or
+	 * dynamic. A static string synth field can only accept a
+	 * same-sized static string, which is checked for later.
+	 */
+	if (strstr(hist_field->type, "char[") && field->is_string
+	    && field->is_dynamic)
+		return 0;
+
+	if (strstr(hist_field->type, "long[") && field->is_stack)
+		return 0;
+
+	if (strcmp(field->type, hist_field->type) != 0) {
+		if (field->size != hist_field->size ||
+		    (!field->is_string && field->is_signed != hist_field->is_signed))
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct hist_field *
+trace_action_find_var(struct hist_trigger_data *hist_data,
+		      struct action_data *data,
+		      char *system, char *event, char *var)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	struct hist_field *hist_field;
+
+	var++; /* skip '$' */
+
+	hist_field = find_target_event_var(hist_data, system, event, var);
+	if (!hist_field) {
+		if (!system && data->handler == HANDLER_ONMATCH) {
+			system = data->match_data.event_system;
+			event = data->match_data.event;
+		}
+
+		hist_field = find_event_var(hist_data, system, event, var);
+	}
+
+	if (!hist_field)
+		hist_err(tr, HIST_ERR_PARAM_NOT_FOUND, errpos(var));
+
+	return hist_field;
+}
+
+static struct hist_field *
+trace_action_create_field_var(struct hist_trigger_data *hist_data,
+			      struct action_data *data, char *system,
+			      char *event, char *var)
+{
+	struct hist_field *hist_field = NULL;
+	struct field_var *field_var;
+
+	/*
+	 * First try to create a field var on the target event (the
+	 * currently being defined).  This will create a variable for
+	 * unqualified fields on the target event, or if qualified,
+	 * target fields that have qualified names matching the target.
+	 */
+	field_var = create_target_field_var(hist_data, system, event, var);
+
+	if (field_var && !IS_ERR(field_var)) {
+		save_field_var(hist_data, field_var);
+		hist_field = field_var->var;
+	} else {
+		field_var = NULL;
+		/*
+		 * If no explicit system.event is specified, default to
+		 * looking for fields on the onmatch(system.event.xxx)
+		 * event.
+		 */
+		if (!system && data->handler == HANDLER_ONMATCH) {
+			system = data->match_data.event_system;
+			event = data->match_data.event;
+		}
+
+		if (!event)
+			goto free;
+		/*
+		 * At this point, we're looking at a field on another
+		 * event.  Because we can't modify a hist trigger on
+		 * another event to add a variable for a field, we need
+		 * to create a new trigger on that event and create the
+		 * variable at the same time.
+		 */
+		hist_field = create_field_var_hist(hist_data, system, event, var);
+		if (IS_ERR(hist_field))
+			goto free;
+	}
+ out:
+	return hist_field;
+ free:
+	destroy_field_var(field_var);
+	hist_field = NULL;
+	goto out;
+}
+
+static int trace_action_create(struct hist_trigger_data *hist_data,
+			       struct action_data *data)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	char *event_name, *param, *system = NULL;
+	struct hist_field *hist_field, *var_ref;
+	unsigned int i;
+	unsigned int field_pos = 0;
+	struct synth_event *event;
+	char *synth_event_name;
+	int var_ref_idx, ret = 0;
+
+	lockdep_assert_held(&event_mutex);
+
+	/* Sanity check to avoid out-of-bound write on 'data->var_ref_idx' */
+	if (data->n_params > SYNTH_FIELDS_MAX)
+		return -EINVAL;
+
+	if (data->use_trace_keyword)
+		synth_event_name = data->synth_event_name;
+	else
+		synth_event_name = data->action_name;
+
+	event = find_synth_event(synth_event_name);
+	if (!event) {
+		hist_err(tr, HIST_ERR_SYNTH_EVENT_NOT_FOUND, errpos(synth_event_name));
+		return -EINVAL;
+	}
+
+	event->ref++;
+
+	for (i = 0; i < data->n_params; i++) {
+		char *p;
+
+		p = param = kstrdup(data->params[i], GFP_KERNEL);
+		if (!param) {
+			ret = -ENOMEM;
+			goto err;
+		}
+
+		system = strsep(&param, ".");
+		if (!param) {
+			param = (char *)system;
+			system = event_name = NULL;
+		} else {
+			event_name = strsep(&param, ".");
+			if (!param) {
+				kfree(p);
+				ret = -EINVAL;
+				goto err;
+			}
+		}
+
+		if (param[0] == '$')
+			hist_field = trace_action_find_var(hist_data, data,
+							   system, event_name,
+							   param);
+		else
+			hist_field = trace_action_create_field_var(hist_data,
+								   data,
+								   system,
+								   event_name,
+								   param);
+
+		if (!hist_field) {
+			kfree(p);
+			ret = -EINVAL;
+			goto err;
+		}
+
+		if (check_synth_field(event, hist_field, field_pos) == 0) {
+			var_ref = create_var_ref(hist_data, hist_field,
+						 system, event_name);
+			if (!var_ref) {
+				kfree(p);
+				ret = -ENOMEM;
+				goto err;
+			}
+
+			var_ref_idx = find_var_ref_idx(hist_data, var_ref);
+			if (WARN_ON(var_ref_idx < 0)) {
+				kfree(p);
+				ret = var_ref_idx;
+				goto err;
+			}
+
+			data->var_ref_idx[i] = var_ref_idx;
+
+			field_pos++;
+			kfree(p);
+			continue;
+		}
+
+		hist_err(tr, HIST_ERR_SYNTH_TYPE_MISMATCH, errpos(param));
+		kfree(p);
+		ret = -EINVAL;
+		goto err;
+	}
+
+	if (field_pos != event->n_fields) {
+		hist_err(tr, HIST_ERR_SYNTH_COUNT_MISMATCH, errpos(event->name));
+		ret = -EINVAL;
+		goto err;
+	}
+
+	data->synth_event = event;
+ out:
+	return ret;
+ err:
+	event->ref--;
+
+	goto out;
+}
+
+static int action_create(struct hist_trigger_data *hist_data,
+			 struct action_data *data)
+{
+	struct trace_event_file *file = hist_data->event_file;
+	struct trace_array *tr = file->tr;
+	struct track_data *track_data;
+	struct field_var *field_var;
+	unsigned int i;
+	char *param;
+	int ret = 0;
+
+	if (data->action == ACTION_TRACE)
+		return trace_action_create(hist_data, data);
+
+	if (data->action == ACTION_SNAPSHOT) {
+		track_data = track_data_alloc(hist_data->key_size, data, hist_data);
+		if (IS_ERR(track_data)) {
+			ret = PTR_ERR(track_data);
+			goto out;
+		}
+
+		ret = tracing_snapshot_cond_enable(file->tr, track_data,
+						   cond_snapshot_update);
+		if (ret)
+			track_data_free(track_data);
+
+		goto out;
+	}
+
+	if (data->action == ACTION_SAVE) {
+		if (hist_data->n_save_vars) {
+			ret = -EEXIST;
+			hist_err(tr, HIST_ERR_TOO_MANY_SAVE_ACTIONS, 0);
+			goto out;
+		}
+
+		for (i = 0; i < data->n_params; i++) {
+			param = kstrdup(data->params[i], GFP_KERNEL);
+			if (!param) {
+				ret = -ENOMEM;
+				goto out;
+			}
+
+			field_var = create_target_field_var(hist_data, NULL, NULL, param);
+			if (IS_ERR(field_var)) {
+				hist_err(tr, HIST_ERR_FIELD_VAR_CREATE_FAIL,
+					 errpos(param));
+				ret = PTR_ERR(field_var);
+				kfree(param);
+				goto out;
+			}
+
+			hist_data->save_vars[hist_data->n_save_vars++] = field_var;
+			if (field_var->val->flags & HIST_FIELD_FL_STRING)
+				hist_data->n_save_var_str++;
+			kfree(param);
+		}
+	}
+ out:
+	return ret;
+}
+
+static int onmatch_create(struct hist_trigger_data *hist_data,
+			  struct action_data *data)
+{
+	return action_create(hist_data, data);
+}
+
+static struct action_data *onmatch_parse(struct trace_array *tr, char *str)
+{
+	char *match_event, *match_event_system;
+	struct action_data *data;
+	int ret = -EINVAL;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return ERR_PTR(-ENOMEM);
+
+	match_event = strsep(&str, ")");
+	if (!match_event || !str) {
+		hist_err(tr, HIST_ERR_NO_CLOSING_PAREN, errpos(match_event));
+		goto free;
+	}
+
+	match_event_system = strsep(&match_event, ".");
+	if (!match_event) {
+		hist_err(tr, HIST_ERR_SUBSYS_NOT_FOUND, errpos(match_event_system));
+		goto free;
+	}
+
+	if (IS_ERR(event_file(tr, match_event_system, match_event))) {
+		hist_err(tr, HIST_ERR_INVALID_SUBSYS_EVENT, errpos(match_event));
+		goto free;
+	}
+
+	data->match_data.event = kstrdup(match_event, GFP_KERNEL);
+	if (!data->match_data.event) {
+		ret = -ENOMEM;
+		goto free;
+	}
+
+	data->match_data.event_system = kstrdup(match_event_system, GFP_KERNEL);
+	if (!data->match_data.event_system) {
+		ret = -ENOMEM;
+		goto free;
+	}
+
+	ret = action_parse(tr, str, data, HANDLER_ONMATCH);
+	if (ret)
+		goto free;
+ out:
+	return data;
+ free:
+	onmatch_destroy(data);
+	data = ERR_PTR(ret);
+	goto out;
+}
+
+static int create_hitcount_val(struct hist_trigger_data *hist_data)
+{
+	hist_data->fields[HITCOUNT_IDX] =
+		create_hist_field(hist_data, NULL, HIST_FIELD_FL_HITCOUNT, NULL);
+	if (!hist_data->fields[HITCOUNT_IDX])
+		return -ENOMEM;
+
+	hist_data->n_vals++;
+	hist_data->n_fields++;
+
+	if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int __create_val_field(struct hist_trigger_data *hist_data,
+			      unsigned int val_idx,
+			      struct trace_event_file *file,
+			      char *var_name, char *field_str,
+			      unsigned long flags)
+{
+	struct hist_field *hist_field;
+	int ret = 0, n_subexprs = 0;
+
+	hist_field = parse_expr(hist_data, file, field_str, flags, var_name, &n_subexprs);
+	if (IS_ERR(hist_field)) {
+		ret = PTR_ERR(hist_field);
+		goto out;
+	}
+
+	/* values and variables should not have some modifiers */
+	if (hist_field->flags & HIST_FIELD_FL_VAR) {
+		/* Variable */
+		if (hist_field->flags & (HIST_FIELD_FL_GRAPH | HIST_FIELD_FL_PERCENT |
+					 HIST_FIELD_FL_BUCKET | HIST_FIELD_FL_LOG2))
+			goto err;
+	} else {
+		/* Value */
+		if (hist_field->flags & (HIST_FIELD_FL_GRAPH | HIST_FIELD_FL_PERCENT |
+					 HIST_FIELD_FL_BUCKET | HIST_FIELD_FL_LOG2 |
+					 HIST_FIELD_FL_SYM | HIST_FIELD_FL_SYM_OFFSET |
+					 HIST_FIELD_FL_SYSCALL | HIST_FIELD_FL_STACKTRACE))
+			goto err;
+	}
+
+	hist_data->fields[val_idx] = hist_field;
+
+	++hist_data->n_vals;
+	++hist_data->n_fields;
+
+	if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
+		ret = -EINVAL;
+ out:
+	return ret;
+ err:
+	hist_err(file->tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(field_str));
+	return -EINVAL;
+}
+
+static int create_val_field(struct hist_trigger_data *hist_data,
+			    unsigned int val_idx,
+			    struct trace_event_file *file,
+			    char *field_str)
+{
+	if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX))
+		return -EINVAL;
+
+	return __create_val_field(hist_data, val_idx, file, NULL, field_str, 0);
+}
+
+static const char no_comm[] = "(no comm)";
+
+static u64 hist_field_execname(struct hist_field *hist_field,
+			       struct tracing_map_elt *elt,
+			       struct trace_buffer *buffer,
+			       struct ring_buffer_event *rbe,
+			       void *event)
+{
+	struct hist_elt_data *elt_data;
+
+	if (WARN_ON_ONCE(!elt))
+		return (u64)(unsigned long)no_comm;
+
+	elt_data = elt->private_data;
+
+	if (WARN_ON_ONCE(!elt_data->comm))
+		return (u64)(unsigned long)no_comm;
+
+	return (u64)(unsigned long)(elt_data->comm);
+}
+
+static u64 hist_fn_call(struct hist_field *hist_field,
+			struct tracing_map_elt *elt,
+			struct trace_buffer *buffer,
+			struct ring_buffer_event *rbe,
+			void *event)
+{
+	switch (hist_field->fn_num) {
+	case HIST_FIELD_FN_VAR_REF:
+		return hist_field_var_ref(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_COUNTER:
+		return hist_field_counter(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_CONST:
+		return hist_field_const(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_LOG2:
+		return hist_field_log2(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_BUCKET:
+		return hist_field_bucket(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_TIMESTAMP:
+		return hist_field_timestamp(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_CPU:
+		return hist_field_cpu(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_STRING:
+		return hist_field_string(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_DYNSTRING:
+		return hist_field_dynstring(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_RELDYNSTRING:
+		return hist_field_reldynstring(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_PSTRING:
+		return hist_field_pstring(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_S64:
+		return hist_field_s64(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_U64:
+		return hist_field_u64(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_S32:
+		return hist_field_s32(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_U32:
+		return hist_field_u32(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_S16:
+		return hist_field_s16(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_U16:
+		return hist_field_u16(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_S8:
+		return hist_field_s8(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_U8:
+		return hist_field_u8(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_UMINUS:
+		return hist_field_unary_minus(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_MINUS:
+		return hist_field_minus(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_PLUS:
+		return hist_field_plus(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_DIV:
+		return hist_field_div(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_MULT:
+		return hist_field_mult(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_DIV_POWER2:
+		return div_by_power_of_two(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_DIV_NOT_POWER2:
+		return div_by_not_power_of_two(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_DIV_MULT_SHIFT:
+		return div_by_mult_and_shift(hist_field, elt, buffer, rbe, event);
+	case HIST_FIELD_FN_EXECNAME:
+		return hist_field_execname(hist_field, elt, buffer, rbe, event);
+	default:
+		return 0;
+	}
+}
+
+/* Convert a var that points to common_pid.execname to a string */
+static void update_var_execname(struct hist_field *hist_field)
+{
+	hist_field->flags = HIST_FIELD_FL_STRING | HIST_FIELD_FL_VAR |
+		HIST_FIELD_FL_EXECNAME;
+	hist_field->size = MAX_FILTER_STR_VAL;
+	hist_field->is_signed = 0;
+
+	kfree_const(hist_field->type);
+	hist_field->type = "char[]";
+
+	hist_field->fn_num = HIST_FIELD_FN_EXECNAME;
+}
+
+static int create_var_field(struct hist_trigger_data *hist_data,
+			    unsigned int val_idx,
+			    struct trace_event_file *file,
+			    char *var_name, char *expr_str)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	unsigned long flags = 0;
+	int ret;
+
+	if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
+		return -EINVAL;
+
+	if (find_var(hist_data, file, var_name) && !hist_data->remove) {
+		hist_err(tr, HIST_ERR_DUPLICATE_VAR, errpos(var_name));
+		return -EINVAL;
+	}
+
+	flags |= HIST_FIELD_FL_VAR;
+	hist_data->n_vars++;
+	if (WARN_ON(hist_data->n_vars > TRACING_MAP_VARS_MAX))
+		return -EINVAL;
+
+	ret = __create_val_field(hist_data, val_idx, file, var_name, expr_str, flags);
+
+	if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_EXECNAME)
+		update_var_execname(hist_data->fields[val_idx]);
+
+	if (!ret && hist_data->fields[val_idx]->flags & HIST_FIELD_FL_STRING)
+		hist_data->fields[val_idx]->var_str_idx = hist_data->n_var_str++;
+
+	return ret;
+}
+
+static int create_val_fields(struct hist_trigger_data *hist_data,
+			     struct trace_event_file *file)
+{
+	char *fields_str, *field_str;
+	unsigned int i, j = 1;
+	int ret;
+
+	ret = create_hitcount_val(hist_data);
+	if (ret)
+		goto out;
+
+	fields_str = hist_data->attrs->vals_str;
+	if (!fields_str)
+		goto out;
+
+	for (i = 0, j = 1; i < TRACING_MAP_VALS_MAX &&
+		     j < TRACING_MAP_VALS_MAX; i++) {
+		field_str = strsep(&fields_str, ",");
+		if (!field_str)
+			break;
+
+		if (strcmp(field_str, "hitcount") == 0)
+			continue;
+
+		ret = create_val_field(hist_data, j++, file, field_str);
+		if (ret)
+			goto out;
+	}
+
+	if (fields_str && (strcmp(fields_str, "hitcount") != 0))
+		ret = -EINVAL;
+ out:
+	return ret;
+}
+
+static int create_key_field(struct hist_trigger_data *hist_data,
+			    unsigned int key_idx,
+			    unsigned int key_offset,
+			    struct trace_event_file *file,
+			    char *field_str)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	struct hist_field *hist_field = NULL;
+	unsigned long flags = 0;
+	unsigned int key_size;
+	int ret = 0, n_subexprs = 0;
+
+	if (WARN_ON(key_idx >= HIST_FIELDS_MAX))
+		return -EINVAL;
+
+	flags |= HIST_FIELD_FL_KEY;
+
+	if (strcmp(field_str, "stacktrace") == 0) {
+		flags |= HIST_FIELD_FL_STACKTRACE;
+		key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH;
+		hist_field = create_hist_field(hist_data, NULL, flags, NULL);
+	} else {
+		hist_field = parse_expr(hist_data, file, field_str, flags,
+					NULL, &n_subexprs);
+		if (IS_ERR(hist_field)) {
+			ret = PTR_ERR(hist_field);
+			goto out;
+		}
+
+		if (field_has_hist_vars(hist_field, 0))	{
+			hist_err(tr, HIST_ERR_INVALID_REF_KEY, errpos(field_str));
+			destroy_hist_field(hist_field, 0);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		key_size = hist_field->size;
+	}
+
+	hist_data->fields[key_idx] = hist_field;
+
+	key_size = ALIGN(key_size, sizeof(u64));
+	hist_data->fields[key_idx]->size = key_size;
+	hist_data->fields[key_idx]->offset = key_offset;
+
+	hist_data->key_size += key_size;
+
+	if (hist_data->key_size > HIST_KEY_SIZE_MAX) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	hist_data->n_keys++;
+	hist_data->n_fields++;
+
+	if (WARN_ON(hist_data->n_keys > TRACING_MAP_KEYS_MAX))
+		return -EINVAL;
+
+	ret = key_size;
+ out:
+	return ret;
+}
+
+static int create_key_fields(struct hist_trigger_data *hist_data,
+			     struct trace_event_file *file)
+{
+	unsigned int i, key_offset = 0, n_vals = hist_data->n_vals;
+	char *fields_str, *field_str;
+	int ret = -EINVAL;
+
+	fields_str = hist_data->attrs->keys_str;
+	if (!fields_str)
+		goto out;
+
+	for (i = n_vals; i < n_vals + TRACING_MAP_KEYS_MAX; i++) {
+		field_str = strsep(&fields_str, ",");
+		if (!field_str)
+			break;
+		ret = create_key_field(hist_data, i, key_offset,
+				       file, field_str);
+		if (ret < 0)
+			goto out;
+		key_offset += ret;
+	}
+	if (fields_str) {
+		ret = -EINVAL;
+		goto out;
+	}
+	ret = 0;
+ out:
+	return ret;
+}
+
+static int create_var_fields(struct hist_trigger_data *hist_data,
+			     struct trace_event_file *file)
+{
+	unsigned int i, j = hist_data->n_vals;
+	int ret = 0;
+
+	unsigned int n_vars = hist_data->attrs->var_defs.n_vars;
+
+	for (i = 0; i < n_vars; i++) {
+		char *var_name = hist_data->attrs->var_defs.name[i];
+		char *expr = hist_data->attrs->var_defs.expr[i];
+
+		ret = create_var_field(hist_data, j++, file, var_name, expr);
+		if (ret)
+			goto out;
+	}
+ out:
+	return ret;
+}
+
+static void free_var_defs(struct hist_trigger_data *hist_data)
+{
+	unsigned int i;
+
+	for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
+		kfree(hist_data->attrs->var_defs.name[i]);
+		kfree(hist_data->attrs->var_defs.expr[i]);
+	}
+
+	hist_data->attrs->var_defs.n_vars = 0;
+}
+
+static int parse_var_defs(struct hist_trigger_data *hist_data)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	char *s, *str, *var_name, *field_str;
+	unsigned int i, j, n_vars = 0;
+	int ret = 0;
+
+	for (i = 0; i < hist_data->attrs->n_assignments; i++) {
+		str = hist_data->attrs->assignment_str[i];
+		for (j = 0; j < TRACING_MAP_VARS_MAX; j++) {
+			field_str = strsep(&str, ",");
+			if (!field_str)
+				break;
+
+			var_name = strsep(&field_str, "=");
+			if (!var_name || !field_str) {
+				hist_err(tr, HIST_ERR_MALFORMED_ASSIGNMENT,
+					 errpos(var_name));
+				ret = -EINVAL;
+				goto free;
+			}
+
+			if (n_vars == TRACING_MAP_VARS_MAX) {
+				hist_err(tr, HIST_ERR_TOO_MANY_VARS, errpos(var_name));
+				ret = -EINVAL;
+				goto free;
+			}
+
+			s = kstrdup(var_name, GFP_KERNEL);
+			if (!s) {
+				ret = -ENOMEM;
+				goto free;
+			}
+			hist_data->attrs->var_defs.name[n_vars] = s;
+
+			s = kstrdup(field_str, GFP_KERNEL);
+			if (!s) {
+				kfree(hist_data->attrs->var_defs.name[n_vars]);
+				hist_data->attrs->var_defs.name[n_vars] = NULL;
+				ret = -ENOMEM;
+				goto free;
+			}
+			hist_data->attrs->var_defs.expr[n_vars++] = s;
+
+			hist_data->attrs->var_defs.n_vars = n_vars;
+		}
+	}
+
+	return ret;
+ free:
+	free_var_defs(hist_data);
+
+	return ret;
+}
+
+static int create_hist_fields(struct hist_trigger_data *hist_data,
+			      struct trace_event_file *file)
+{
+	int ret;
+
+	ret = parse_var_defs(hist_data);
+	if (ret)
+		return ret;
+
+	ret = create_val_fields(hist_data, file);
+	if (ret)
+		goto out;
+
+	ret = create_var_fields(hist_data, file);
+	if (ret)
+		goto out;
+
+	ret = create_key_fields(hist_data, file);
+
+ out:
+	free_var_defs(hist_data);
+
+	return ret;
+}
+
+static int is_descending(struct trace_array *tr, const char *str)
+{
+	if (!str)
+		return 0;
+
+	if (strcmp(str, "descending") == 0)
+		return 1;
+
+	if (strcmp(str, "ascending") == 0)
+		return 0;
+
+	hist_err(tr, HIST_ERR_INVALID_SORT_MODIFIER, errpos((char *)str));
+
+	return -EINVAL;
+}
+
+static int create_sort_keys(struct hist_trigger_data *hist_data)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	char *fields_str = hist_data->attrs->sort_key_str;
+	struct tracing_map_sort_key *sort_key;
+	int descending, ret = 0;
+	unsigned int i, j, k;
+
+	hist_data->n_sort_keys = 1; /* we always have at least one, hitcount */
+
+	if (!fields_str)
+		goto out;
+
+	for (i = 0; i < TRACING_MAP_SORT_KEYS_MAX; i++) {
+		struct hist_field *hist_field;
+		char *field_str, *field_name;
+		const char *test_name;
+
+		sort_key = &hist_data->sort_keys[i];
+
+		field_str = strsep(&fields_str, ",");
+		if (!field_str)
+			break;
+
+		if (!*field_str) {
+			ret = -EINVAL;
+			hist_err(tr, HIST_ERR_EMPTY_SORT_FIELD, errpos("sort="));
+			break;
+		}
+
+		if ((i == TRACING_MAP_SORT_KEYS_MAX - 1) && fields_str) {
+			hist_err(tr, HIST_ERR_TOO_MANY_SORT_FIELDS, errpos("sort="));
+			ret = -EINVAL;
+			break;
+		}
+
+		field_name = strsep(&field_str, ".");
+		if (!field_name || !*field_name) {
+			ret = -EINVAL;
+			hist_err(tr, HIST_ERR_EMPTY_SORT_FIELD, errpos("sort="));
+			break;
+		}
+
+		if (strcmp(field_name, "hitcount") == 0) {
+			descending = is_descending(tr, field_str);
+			if (descending < 0) {
+				ret = descending;
+				break;
+			}
+			sort_key->descending = descending;
+			continue;
+		}
+
+		for (j = 1, k = 1; j < hist_data->n_fields; j++) {
+			unsigned int idx;
+
+			hist_field = hist_data->fields[j];
+			if (hist_field->flags & HIST_FIELD_FL_VAR)
+				continue;
+
+			idx = k++;
+
+			test_name = hist_field_name(hist_field, 0);
+
+			if (strcmp(field_name, test_name) == 0) {
+				sort_key->field_idx = idx;
+				descending = is_descending(tr, field_str);
+				if (descending < 0) {
+					ret = descending;
+					goto out;
+				}
+				sort_key->descending = descending;
+				break;
+			}
+		}
+		if (j == hist_data->n_fields) {
+			ret = -EINVAL;
+			hist_err(tr, HIST_ERR_INVALID_SORT_FIELD, errpos(field_name));
+			break;
+		}
+	}
+
+	hist_data->n_sort_keys = i;
+ out:
+	return ret;
+}
+
+static void destroy_actions(struct hist_trigger_data *hist_data)
+{
+	unsigned int i;
+
+	for (i = 0; i < hist_data->n_actions; i++) {
+		struct action_data *data = hist_data->actions[i];
+
+		if (data->handler == HANDLER_ONMATCH)
+			onmatch_destroy(data);
+		else if (data->handler == HANDLER_ONMAX ||
+			 data->handler == HANDLER_ONCHANGE)
+			track_data_destroy(hist_data, data);
+		else
+			kfree(data);
+	}
+}
+
+static int parse_actions(struct hist_trigger_data *hist_data)
+{
+	struct trace_array *tr = hist_data->event_file->tr;
+	struct action_data *data;
+	unsigned int i;
+	int ret = 0;
+	char *str;
+	int len;
+
+	for (i = 0; i < hist_data->attrs->n_actions; i++) {
+		str = hist_data->attrs->action_str[i];
+
+		if ((len = str_has_prefix(str, "onmatch("))) {
+			char *action_str = str + len;
+
+			data = onmatch_parse(tr, action_str);
+			if (IS_ERR(data)) {
+				ret = PTR_ERR(data);
+				break;
+			}
+		} else if ((len = str_has_prefix(str, "onmax("))) {
+			char *action_str = str + len;
+
+			data = track_data_parse(hist_data, action_str,
+						HANDLER_ONMAX);
+			if (IS_ERR(data)) {
+				ret = PTR_ERR(data);
+				break;
+			}
+		} else if ((len = str_has_prefix(str, "onchange("))) {
+			char *action_str = str + len;
+
+			data = track_data_parse(hist_data, action_str,
+						HANDLER_ONCHANGE);
+			if (IS_ERR(data)) {
+				ret = PTR_ERR(data);
+				break;
+			}
+		} else {
+			ret = -EINVAL;
+			break;
+		}
+
+		hist_data->actions[hist_data->n_actions++] = data;
+	}
+
+	return ret;
+}
+
+static int create_actions(struct hist_trigger_data *hist_data)
+{
+	struct action_data *data;
+	unsigned int i;
+	int ret = 0;
+
+	for (i = 0; i < hist_data->attrs->n_actions; i++) {
+		data = hist_data->actions[i];
+
+		if (data->handler == HANDLER_ONMATCH) {
+			ret = onmatch_create(hist_data, data);
+			if (ret)
+				break;
+		} else if (data->handler == HANDLER_ONMAX ||
+			   data->handler == HANDLER_ONCHANGE) {
+			ret = track_data_create(hist_data, data);
+			if (ret)
+				break;
+		} else {
+			ret = -EINVAL;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static void print_actions(struct seq_file *m,
+			  struct hist_trigger_data *hist_data,
+			  struct tracing_map_elt *elt)
+{
+	unsigned int i;
+
+	for (i = 0; i < hist_data->n_actions; i++) {
+		struct action_data *data = hist_data->actions[i];
+
+		if (data->action == ACTION_SNAPSHOT)
+			continue;
+
+		if (data->handler == HANDLER_ONMAX ||
+		    data->handler == HANDLER_ONCHANGE)
+			track_data_print(m, hist_data, elt, data);
+	}
+}
+
+static void print_action_spec(struct seq_file *m,
+			      struct hist_trigger_data *hist_data,
+			      struct action_data *data)
+{
+	unsigned int i;
+
+	if (data->action == ACTION_SAVE) {
+		for (i = 0; i < hist_data->n_save_vars; i++) {
+			seq_printf(m, "%s", hist_data->save_vars[i]->var->var.name);
+			if (i < hist_data->n_save_vars - 1)
+				seq_puts(m, ",");
+		}
+	} else if (data->action == ACTION_TRACE) {
+		if (data->use_trace_keyword)
+			seq_printf(m, "%s", data->synth_event_name);
+		for (i = 0; i < data->n_params; i++) {
+			if (i || data->use_trace_keyword)
+				seq_puts(m, ",");
+			seq_printf(m, "%s", data->params[i]);
+		}
+	}
+}
+
+static void print_track_data_spec(struct seq_file *m,
+				  struct hist_trigger_data *hist_data,
+				  struct action_data *data)
+{
+	if (data->handler == HANDLER_ONMAX)
+		seq_puts(m, ":onmax(");
+	else if (data->handler == HANDLER_ONCHANGE)
+		seq_puts(m, ":onchange(");
+	seq_printf(m, "%s", data->track_data.var_str);
+	seq_printf(m, ").%s(", data->action_name);
+
+	print_action_spec(m, hist_data, data);
+
+	seq_puts(m, ")");
+}
+
+static void print_onmatch_spec(struct seq_file *m,
+			       struct hist_trigger_data *hist_data,
+			       struct action_data *data)
+{
+	seq_printf(m, ":onmatch(%s.%s).", data->match_data.event_system,
+		   data->match_data.event);
+
+	seq_printf(m, "%s(", data->action_name);
+
+	print_action_spec(m, hist_data, data);
+
+	seq_puts(m, ")");
+}
+
+static bool actions_match(struct hist_trigger_data *hist_data,
+			  struct hist_trigger_data *hist_data_test)
+{
+	unsigned int i, j;
+
+	if (hist_data->n_actions != hist_data_test->n_actions)
+		return false;
+
+	for (i = 0; i < hist_data->n_actions; i++) {
+		struct action_data *data = hist_data->actions[i];
+		struct action_data *data_test = hist_data_test->actions[i];
+		char *action_name, *action_name_test;
+
+		if (data->handler != data_test->handler)
+			return false;
+		if (data->action != data_test->action)
+			return false;
+
+		if (data->n_params != data_test->n_params)
+			return false;
+
+		for (j = 0; j < data->n_params; j++) {
+			if (strcmp(data->params[j], data_test->params[j]) != 0)
+				return false;
+		}
+
+		if (data->use_trace_keyword)
+			action_name = data->synth_event_name;
+		else
+			action_name = data->action_name;
+
+		if (data_test->use_trace_keyword)
+			action_name_test = data_test->synth_event_name;
+		else
+			action_name_test = data_test->action_name;
+
+		if (strcmp(action_name, action_name_test) != 0)
+			return false;
+
+		if (data->handler == HANDLER_ONMATCH) {
+			if (strcmp(data->match_data.event_system,
+				   data_test->match_data.event_system) != 0)
+				return false;
+			if (strcmp(data->match_data.event,
+				   data_test->match_data.event) != 0)
+				return false;
+		} else if (data->handler == HANDLER_ONMAX ||
+			   data->handler == HANDLER_ONCHANGE) {
+			if (strcmp(data->track_data.var_str,
+				   data_test->track_data.var_str) != 0)
+				return false;
+		}
+	}
+
+	return true;
+}
+
+
+static void print_actions_spec(struct seq_file *m,
+			       struct hist_trigger_data *hist_data)
+{
+	unsigned int i;
+
+	for (i = 0; i < hist_data->n_actions; i++) {
+		struct action_data *data = hist_data->actions[i];
+
+		if (data->handler == HANDLER_ONMATCH)
+			print_onmatch_spec(m, hist_data, data);
+		else if (data->handler == HANDLER_ONMAX ||
+			 data->handler == HANDLER_ONCHANGE)
+			print_track_data_spec(m, hist_data, data);
+	}
+}
+
+static void destroy_field_var_hists(struct hist_trigger_data *hist_data)
+{
+	unsigned int i;
+
+	for (i = 0; i < hist_data->n_field_var_hists; i++) {
+		kfree(hist_data->field_var_hists[i]->cmd);
+		kfree(hist_data->field_var_hists[i]);
+	}
+}
+
+static void destroy_hist_data(struct hist_trigger_data *hist_data)
+{
+	if (!hist_data)
+		return;
+
+	destroy_hist_trigger_attrs(hist_data->attrs);
+	destroy_hist_fields(hist_data);
+	tracing_map_destroy(hist_data->map);
+
+	destroy_actions(hist_data);
+	destroy_field_vars(hist_data);
+	destroy_field_var_hists(hist_data);
+
+	kfree(hist_data);
+}
+
+static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
+{
+	struct tracing_map *map = hist_data->map;
+	struct ftrace_event_field *field;
+	struct hist_field *hist_field;
+	int i, idx = 0;
+
+	for_each_hist_field(i, hist_data) {
+		hist_field = hist_data->fields[i];
+		if (hist_field->flags & HIST_FIELD_FL_KEY) {
+			tracing_map_cmp_fn_t cmp_fn;
+
+			field = hist_field->field;
+
+			if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
+				cmp_fn = tracing_map_cmp_none;
+			else if (!field || hist_field->flags & HIST_FIELD_FL_CPU)
+				cmp_fn = tracing_map_cmp_num(hist_field->size,
+							     hist_field->is_signed);
+			else if (is_string_field(field))
+				cmp_fn = tracing_map_cmp_string;
+			else
+				cmp_fn = tracing_map_cmp_num(field->size,
+							     field->is_signed);
+			idx = tracing_map_add_key_field(map,
+							hist_field->offset,
+							cmp_fn);
+		} else if (!(hist_field->flags & HIST_FIELD_FL_VAR))
+			idx = tracing_map_add_sum_field(map);
+
+		if (idx < 0)
+			return idx;
+
+		if (hist_field->flags & HIST_FIELD_FL_VAR) {
+			idx = tracing_map_add_var(map);
+			if (idx < 0)
+				return idx;
+			hist_field->var.idx = idx;
+			hist_field->var.hist_data = hist_data;
+		}
+	}
+
+	return 0;
+}
+
+static struct hist_trigger_data *
+create_hist_data(unsigned int map_bits,
+		 struct hist_trigger_attrs *attrs,
+		 struct trace_event_file *file,
+		 bool remove)
+{
+	const struct tracing_map_ops *map_ops = NULL;
+	struct hist_trigger_data *hist_data;
+	int ret = 0;
+
+	hist_data = kzalloc(sizeof(*hist_data), GFP_KERNEL);
+	if (!hist_data)
+		return ERR_PTR(-ENOMEM);
+
+	hist_data->attrs = attrs;
+	hist_data->remove = remove;
+	hist_data->event_file = file;
+
+	ret = parse_actions(hist_data);
+	if (ret)
+		goto free;
+
+	ret = create_hist_fields(hist_data, file);
+	if (ret)
+		goto free;
+
+	ret = create_sort_keys(hist_data);
+	if (ret)
+		goto free;
+
+	map_ops = &hist_trigger_elt_data_ops;
+
+	hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
+					    map_ops, hist_data);
+	if (IS_ERR(hist_data->map)) {
+		ret = PTR_ERR(hist_data->map);
+		hist_data->map = NULL;
+		goto free;
+	}
+
+	ret = create_tracing_map_fields(hist_data);
+	if (ret)
+		goto free;
+ out:
+	return hist_data;
+ free:
+	hist_data->attrs = NULL;
+
+	destroy_hist_data(hist_data);
+
+	hist_data = ERR_PTR(ret);
+
+	goto out;
+}
+
+static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
+				    struct tracing_map_elt *elt,
+				    struct trace_buffer *buffer, void *rec,
+				    struct ring_buffer_event *rbe,
+				    u64 *var_ref_vals)
+{
+	struct hist_elt_data *elt_data;
+	struct hist_field *hist_field;
+	unsigned int i, var_idx;
+	u64 hist_val;
+
+	elt_data = elt->private_data;
+	elt_data->var_ref_vals = var_ref_vals;
+
+	for_each_hist_val_field(i, hist_data) {
+		hist_field = hist_data->fields[i];
+		hist_val = hist_fn_call(hist_field, elt, buffer, rbe, rec);
+		if (hist_field->flags & HIST_FIELD_FL_VAR) {
+			var_idx = hist_field->var.idx;
+
+			if (hist_field->flags & HIST_FIELD_FL_STRING) {
+				unsigned int str_start, var_str_idx, idx;
+				char *str, *val_str;
+				unsigned int size;
+
+				str_start = hist_data->n_field_var_str +
+					hist_data->n_save_var_str;
+				var_str_idx = hist_field->var_str_idx;
+				idx = str_start + var_str_idx;
+
+				str = elt_data->field_var_str[idx];
+				val_str = (char *)(uintptr_t)hist_val;
+
+				size = min(hist_field->size, STR_VAR_LEN_MAX);
+				strscpy(str, val_str, size);
+
+				hist_val = (u64)(uintptr_t)str;
+			}
+			tracing_map_set_var(elt, var_idx, hist_val);
+			continue;
+		}
+		tracing_map_update_sum(elt, i, hist_val);
+	}
+
+	for_each_hist_key_field(i, hist_data) {
+		hist_field = hist_data->fields[i];
+		if (hist_field->flags & HIST_FIELD_FL_VAR) {
+			hist_val = hist_fn_call(hist_field, elt, buffer, rbe, rec);
+			var_idx = hist_field->var.idx;
+			tracing_map_set_var(elt, var_idx, hist_val);
+		}
+	}
+
+	update_field_vars(hist_data, elt, buffer, rbe, rec);
+}
+
+static inline void add_to_key(char *compound_key, void *key,
+			      struct hist_field *key_field, void *rec)
+{
+	size_t size = key_field->size;
+
+	if (key_field->flags & HIST_FIELD_FL_STRING) {
+		struct ftrace_event_field *field;
+
+		field = key_field->field;
+		if (field->filter_type == FILTER_DYN_STRING ||
+		    field->filter_type == FILTER_RDYN_STRING)
+			size = *(u32 *)(rec + field->offset) >> 16;
+		else if (field->filter_type == FILTER_STATIC_STRING)
+			size = field->size;
+
+		/* ensure NULL-termination */
+		if (size > key_field->size - 1)
+			size = key_field->size - 1;
+
+		strncpy(compound_key + key_field->offset, (char *)key, size);
+	} else
+		memcpy(compound_key + key_field->offset, key, size);
+}
+
+static void
+hist_trigger_actions(struct hist_trigger_data *hist_data,
+		     struct tracing_map_elt *elt,
+		     struct trace_buffer *buffer, void *rec,
+		     struct ring_buffer_event *rbe, void *key,
+		     u64 *var_ref_vals)
+{
+	struct action_data *data;
+	unsigned int i;
+
+	for (i = 0; i < hist_data->n_actions; i++) {
+		data = hist_data->actions[i];
+		data->fn(hist_data, elt, buffer, rec, rbe, key, data, var_ref_vals);
+	}
+}
+
+static void event_hist_trigger(struct event_trigger_data *data,
+			       struct trace_buffer *buffer, void *rec,
+			       struct ring_buffer_event *rbe)
+{
+	struct hist_trigger_data *hist_data = data->private_data;
+	bool use_compound_key = (hist_data->n_keys > 1);
+	unsigned long entries[HIST_STACKTRACE_DEPTH];
+	u64 var_ref_vals[TRACING_MAP_VARS_MAX];
+	char compound_key[HIST_KEY_SIZE_MAX];
+	struct tracing_map_elt *elt = NULL;
+	struct hist_field *key_field;
+	u64 field_contents;
+	void *key = NULL;
+	unsigned int i;
+
+	if (unlikely(!rbe))
+		return;
+
+	memset(compound_key, 0, hist_data->key_size);
+
+	for_each_hist_key_field(i, hist_data) {
+		key_field = hist_data->fields[i];
+
+		if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
+			memset(entries, 0, HIST_STACKTRACE_SIZE);
+			stack_trace_save(entries, HIST_STACKTRACE_DEPTH,
+					 HIST_STACKTRACE_SKIP);
+			key = entries;
+		} else {
+			field_contents = hist_fn_call(key_field, elt, buffer, rbe, rec);
+			if (key_field->flags & HIST_FIELD_FL_STRING) {
+				key = (void *)(unsigned long)field_contents;
+				use_compound_key = true;
+			} else
+				key = (void *)&field_contents;
+		}
+
+		if (use_compound_key)
+			add_to_key(compound_key, key, key_field, rec);
+	}
+
+	if (use_compound_key)
+		key = compound_key;
+
+	if (hist_data->n_var_refs &&
+	    !resolve_var_refs(hist_data, key, var_ref_vals, false))
+		return;
+
+	elt = tracing_map_insert(hist_data->map, key);
+	if (!elt)
+		return;
+
+	hist_trigger_elt_update(hist_data, elt, buffer, rec, rbe, var_ref_vals);
+
+	if (resolve_var_refs(hist_data, key, var_ref_vals, true))
+		hist_trigger_actions(hist_data, elt, buffer, rec, rbe, key, var_ref_vals);
+}
+
+static void hist_trigger_stacktrace_print(struct seq_file *m,
+					  unsigned long *stacktrace_entries,
+					  unsigned int max_entries)
+{
+	unsigned int spaces = 8;
+	unsigned int i;
+
+	for (i = 0; i < max_entries; i++) {
+		if (!stacktrace_entries[i])
+			return;
+
+		seq_printf(m, "%*c", 1 + spaces, ' ');
+		seq_printf(m, "%pS\n", (void*)stacktrace_entries[i]);
+	}
+}
+
+static void hist_trigger_print_key(struct seq_file *m,
+				   struct hist_trigger_data *hist_data,
+				   void *key,
+				   struct tracing_map_elt *elt)
+{
+	struct hist_field *key_field;
+	bool multiline = false;
+	const char *field_name;
+	unsigned int i;
+	u64 uval;
+
+	seq_puts(m, "{ ");
+
+	for_each_hist_key_field(i, hist_data) {
+		key_field = hist_data->fields[i];
+
+		if (i > hist_data->n_vals)
+			seq_puts(m, ", ");
+
+		field_name = hist_field_name(key_field, 0);
+
+		if (key_field->flags & HIST_FIELD_FL_HEX) {
+			uval = *(u64 *)(key + key_field->offset);
+			seq_printf(m, "%s: %llx", field_name, uval);
+		} else if (key_field->flags & HIST_FIELD_FL_SYM) {
+			uval = *(u64 *)(key + key_field->offset);
+			seq_printf(m, "%s: [%llx] %-45ps", field_name,
+				   uval, (void *)(uintptr_t)uval);
+		} else if (key_field->flags & HIST_FIELD_FL_SYM_OFFSET) {
+			uval = *(u64 *)(key + key_field->offset);
+			seq_printf(m, "%s: [%llx] %-55pS", field_name,
+				   uval, (void *)(uintptr_t)uval);
+		} else if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
+			struct hist_elt_data *elt_data = elt->private_data;
+			char *comm;
+
+			if (WARN_ON_ONCE(!elt_data))
+				return;
+
+			comm = elt_data->comm;
+
+			uval = *(u64 *)(key + key_field->offset);
+			seq_printf(m, "%s: %-16s[%10llu]", field_name,
+				   comm, uval);
+		} else if (key_field->flags & HIST_FIELD_FL_SYSCALL) {
+			const char *syscall_name;
+
+			uval = *(u64 *)(key + key_field->offset);
+			syscall_name = get_syscall_name(uval);
+			if (!syscall_name)
+				syscall_name = "unknown_syscall";
+
+			seq_printf(m, "%s: %-30s[%3llu]", field_name,
+				   syscall_name, uval);
+		} else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
+			seq_puts(m, "stacktrace:\n");
+			hist_trigger_stacktrace_print(m,
+						      key + key_field->offset,
+						      HIST_STACKTRACE_DEPTH);
+			multiline = true;
+		} else if (key_field->flags & HIST_FIELD_FL_LOG2) {
+			seq_printf(m, "%s: ~ 2^%-2llu", field_name,
+				   *(u64 *)(key + key_field->offset));
+		} else if (key_field->flags & HIST_FIELD_FL_BUCKET) {
+			unsigned long buckets = key_field->buckets;
+			uval = *(u64 *)(key + key_field->offset);
+			seq_printf(m, "%s: ~ %llu-%llu", field_name,
+				   uval, uval + buckets -1);
+		} else if (key_field->flags & HIST_FIELD_FL_STRING) {
+			seq_printf(m, "%s: %-50s", field_name,
+				   (char *)(key + key_field->offset));
+		} else {
+			uval = *(u64 *)(key + key_field->offset);
+			seq_printf(m, "%s: %10llu", field_name, uval);
+		}
+	}
+
+	if (!multiline)
+		seq_puts(m, " ");
+
+	seq_puts(m, "}");
+}
+
+/* Get the 100 times of the percentage of @val in @total */
+static inline unsigned int __get_percentage(u64 val, u64 total)
+{
+	if (!total)
+		goto div0;
+
+	if (val < (U64_MAX / 10000))
+		return (unsigned int)div64_ul(val * 10000, total);
+
+	total = div64_u64(total, 10000);
+	if (!total)
+		goto div0;
+
+	return (unsigned int)div64_ul(val, total);
+div0:
+	return val ? UINT_MAX : 0;
+}
+
+#define BAR_CHAR '#'
+
+static inline const char *__fill_bar_str(char *buf, int size, u64 val, u64 max)
+{
+	unsigned int len = __get_percentage(val, max);
+	int i;
+
+	if (len == UINT_MAX) {
+		snprintf(buf, size, "[ERROR]");
+		return buf;
+	}
+
+	len = len * size / 10000;
+	for (i = 0; i < len && i < size; i++)
+		buf[i] = BAR_CHAR;
+	while (i < size)
+		buf[i++] = ' ';
+	buf[size] = '\0';
+
+	return buf;
+}
+
+struct hist_val_stat {
+	u64 max;
+	u64 total;
+};
+
+static void hist_trigger_print_val(struct seq_file *m, unsigned int idx,
+				   const char *field_name, unsigned long flags,
+				   struct hist_val_stat *stats,
+				   struct tracing_map_elt *elt)
+{
+	u64 val = tracing_map_read_sum(elt, idx);
+	unsigned int pc;
+	char bar[21];
+
+	if (flags & HIST_FIELD_FL_PERCENT) {
+		pc = __get_percentage(val, stats[idx].total);
+		if (pc == UINT_MAX)
+			seq_printf(m, " %s (%%):[ERROR]", field_name);
+		else
+			seq_printf(m, " %s (%%): %3u.%02u", field_name,
+					pc / 100, pc % 100);
+	} else if (flags & HIST_FIELD_FL_GRAPH) {
+		seq_printf(m, " %s: %20s", field_name,
+			   __fill_bar_str(bar, 20, val, stats[idx].max));
+	} else if (flags & HIST_FIELD_FL_HEX) {
+		seq_printf(m, " %s: %10llx", field_name, val);
+	} else {
+		seq_printf(m, " %s: %10llu", field_name, val);
+	}
+}
+
+static void hist_trigger_entry_print(struct seq_file *m,
+				     struct hist_trigger_data *hist_data,
+				     struct hist_val_stat *stats,
+				     void *key,
+				     struct tracing_map_elt *elt)
+{
+	const char *field_name;
+	unsigned int i = HITCOUNT_IDX;
+	unsigned long flags;
+
+	hist_trigger_print_key(m, hist_data, key, elt);
+
+	/* At first, show the raw hitcount always */
+	hist_trigger_print_val(m, i, "hitcount", 0, stats, elt);
+
+	for (i = 1; i < hist_data->n_vals; i++) {
+		field_name = hist_field_name(hist_data->fields[i], 0);
+		flags = hist_data->fields[i]->flags;
+
+		if (flags & HIST_FIELD_FL_VAR || flags & HIST_FIELD_FL_EXPR)
+			continue;
+
+		seq_puts(m, " ");
+		hist_trigger_print_val(m, i, field_name, flags, stats, elt);
+	}
+
+	print_actions(m, hist_data, elt);
+
+	seq_puts(m, "\n");
+}
+
+static int print_entries(struct seq_file *m,
+			 struct hist_trigger_data *hist_data)
+{
+	struct tracing_map_sort_entry **sort_entries = NULL;
+	struct tracing_map *map = hist_data->map;
+	int i, j, n_entries;
+	struct hist_val_stat *stats = NULL;
+	u64 val;
+
+	n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
+					     hist_data->n_sort_keys,
+					     &sort_entries);
+	if (n_entries < 0)
+		return n_entries;
+
+	/* Calculate the max and the total for each field if needed. */
+	for (j = 0; j < hist_data->n_vals; j++) {
+		if (!(hist_data->fields[j]->flags &
+			(HIST_FIELD_FL_PERCENT | HIST_FIELD_FL_GRAPH)))
+			continue;
+		if (!stats) {
+			stats = kcalloc(hist_data->n_vals, sizeof(*stats),
+				       GFP_KERNEL);
+			if (!stats) {
+				n_entries = -ENOMEM;
+				goto out;
+			}
+		}
+		for (i = 0; i < n_entries; i++) {
+			val = tracing_map_read_sum(sort_entries[i]->elt, j);
+			stats[j].total += val;
+			if (stats[j].max < val)
+				stats[j].max = val;
+		}
+	}
+
+	for (i = 0; i < n_entries; i++)
+		hist_trigger_entry_print(m, hist_data, stats,
+					 sort_entries[i]->key,
+					 sort_entries[i]->elt);
+
+	kfree(stats);
+out:
+	tracing_map_destroy_sort_entries(sort_entries, n_entries);
+
+	return n_entries;
+}
+
+static void hist_trigger_show(struct seq_file *m,
+			      struct event_trigger_data *data, int n)
+{
+	struct hist_trigger_data *hist_data;
+	int n_entries;
+
+	if (n > 0)
+		seq_puts(m, "\n\n");
+
+	seq_puts(m, "# event histogram\n#\n# trigger info: ");
+	data->ops->print(m, data);
+	seq_puts(m, "#\n\n");
+
+	hist_data = data->private_data;
+	n_entries = print_entries(m, hist_data);
+	if (n_entries < 0)
+		n_entries = 0;
+
+	track_data_snapshot_print(m, hist_data);
+
+	seq_printf(m, "\nTotals:\n    Hits: %llu\n    Entries: %u\n    Dropped: %llu\n",
+		   (u64)atomic64_read(&hist_data->map->hits),
+		   n_entries, (u64)atomic64_read(&hist_data->map->drops));
+}
+
+static int hist_show(struct seq_file *m, void *v)
+{
+	struct event_trigger_data *data;
+	struct trace_event_file *event_file;
+	int n = 0, ret = 0;
+
+	mutex_lock(&event_mutex);
+
+	event_file = event_file_data(m->private);
+	if (unlikely(!event_file)) {
+		ret = -ENODEV;
+		goto out_unlock;
+	}
+
+	list_for_each_entry(data, &event_file->triggers, list) {
+		if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
+			hist_trigger_show(m, data, n++);
+	}
+
+ out_unlock:
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+static int event_hist_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = tracing_open_file_tr(inode, file);
+	if (ret)
+		return ret;
+
+	/* Clear private_data to avoid warning in single_open() */
+	file->private_data = NULL;
+	return single_open(file, hist_show, file);
+}
+
+const struct file_operations event_hist_fops = {
+	.open = event_hist_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = tracing_single_release_file_tr,
+};
+
+#ifdef CONFIG_HIST_TRIGGERS_DEBUG
+static void hist_field_debug_show_flags(struct seq_file *m,
+					unsigned long flags)
+{
+	seq_puts(m, "      flags:\n");
+
+	if (flags & HIST_FIELD_FL_KEY)
+		seq_puts(m, "        HIST_FIELD_FL_KEY\n");
+	else if (flags & HIST_FIELD_FL_HITCOUNT)
+		seq_puts(m, "        VAL: HIST_FIELD_FL_HITCOUNT\n");
+	else if (flags & HIST_FIELD_FL_VAR)
+		seq_puts(m, "        HIST_FIELD_FL_VAR\n");
+	else if (flags & HIST_FIELD_FL_VAR_REF)
+		seq_puts(m, "        HIST_FIELD_FL_VAR_REF\n");
+	else
+		seq_puts(m, "        VAL: normal u64 value\n");
+
+	if (flags & HIST_FIELD_FL_ALIAS)
+		seq_puts(m, "        HIST_FIELD_FL_ALIAS\n");
+	else if (flags & HIST_FIELD_FL_CONST)
+		seq_puts(m, "        HIST_FIELD_FL_CONST\n");
+}
+
+static int hist_field_debug_show(struct seq_file *m,
+				 struct hist_field *field, unsigned long flags)
+{
+	if ((field->flags & flags) != flags) {
+		seq_printf(m, "ERROR: bad flags - %lx\n", flags);
+		return -EINVAL;
+	}
+
+	hist_field_debug_show_flags(m, field->flags);
+	if (field->field)
+		seq_printf(m, "      ftrace_event_field name: %s\n",
+			   field->field->name);
+
+	if (field->flags & HIST_FIELD_FL_VAR) {
+		seq_printf(m, "      var.name: %s\n", field->var.name);
+		seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
+			   field->var.idx);
+	}
+
+	if (field->flags & HIST_FIELD_FL_CONST)
+		seq_printf(m, "      constant: %llu\n", field->constant);
+
+	if (field->flags & HIST_FIELD_FL_ALIAS)
+		seq_printf(m, "      var_ref_idx (into hist_data->var_refs[]): %u\n",
+			   field->var_ref_idx);
+
+	if (field->flags & HIST_FIELD_FL_VAR_REF) {
+		seq_printf(m, "      name: %s\n", field->name);
+		seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
+			   field->var.idx);
+		seq_printf(m, "      var.hist_data: %p\n", field->var.hist_data);
+		seq_printf(m, "      var_ref_idx (into hist_data->var_refs[]): %u\n",
+			   field->var_ref_idx);
+		if (field->system)
+			seq_printf(m, "      system: %s\n", field->system);
+		if (field->event_name)
+			seq_printf(m, "      event_name: %s\n", field->event_name);
+	}
+
+	seq_printf(m, "      type: %s\n", field->type);
+	seq_printf(m, "      size: %u\n", field->size);
+	seq_printf(m, "      is_signed: %u\n", field->is_signed);
+
+	return 0;
+}
+
+static int field_var_debug_show(struct seq_file *m,
+				struct field_var *field_var, unsigned int i,
+				bool save_vars)
+{
+	const char *vars_name = save_vars ? "save_vars" : "field_vars";
+	struct hist_field *field;
+	int ret = 0;
+
+	seq_printf(m, "\n    hist_data->%s[%d]:\n", vars_name, i);
+
+	field = field_var->var;
+
+	seq_printf(m, "\n      %s[%d].var:\n", vars_name, i);
+
+	hist_field_debug_show_flags(m, field->flags);
+	seq_printf(m, "      var.name: %s\n", field->var.name);
+	seq_printf(m, "      var.idx (into tracing_map_elt.vars[]): %u\n",
+		   field->var.idx);
+
+	field = field_var->val;
+
+	seq_printf(m, "\n      %s[%d].val:\n", vars_name, i);
+	if (field->field)
+		seq_printf(m, "      ftrace_event_field name: %s\n",
+			   field->field->name);
+	else {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	seq_printf(m, "      type: %s\n", field->type);
+	seq_printf(m, "      size: %u\n", field->size);
+	seq_printf(m, "      is_signed: %u\n", field->is_signed);
+out:
+	return ret;
+}
+
+static int hist_action_debug_show(struct seq_file *m,
+				  struct action_data *data, int i)
+{
+	int ret = 0;
+
+	if (data->handler == HANDLER_ONMAX ||
+	    data->handler == HANDLER_ONCHANGE) {
+		seq_printf(m, "\n    hist_data->actions[%d].track_data.var_ref:\n", i);
+		ret = hist_field_debug_show(m, data->track_data.var_ref,
+					    HIST_FIELD_FL_VAR_REF);
+		if (ret)
+			goto out;
+
+		seq_printf(m, "\n    hist_data->actions[%d].track_data.track_var:\n", i);
+		ret = hist_field_debug_show(m, data->track_data.track_var,
+					    HIST_FIELD_FL_VAR);
+		if (ret)
+			goto out;
+	}
+
+	if (data->handler == HANDLER_ONMATCH) {
+		seq_printf(m, "\n    hist_data->actions[%d].match_data.event_system: %s\n",
+			   i, data->match_data.event_system);
+		seq_printf(m, "    hist_data->actions[%d].match_data.event: %s\n",
+			   i, data->match_data.event);
+	}
+out:
+	return ret;
+}
+
+static int hist_actions_debug_show(struct seq_file *m,
+				   struct hist_trigger_data *hist_data)
+{
+	int i, ret = 0;
+
+	if (hist_data->n_actions)
+		seq_puts(m, "\n  action tracking variables (for onmax()/onchange()/onmatch()):\n");
+
+	for (i = 0; i < hist_data->n_actions; i++) {
+		struct action_data *action = hist_data->actions[i];
+
+		ret = hist_action_debug_show(m, action, i);
+		if (ret)
+			goto out;
+	}
+
+	if (hist_data->n_save_vars)
+		seq_puts(m, "\n  save action variables (save() params):\n");
+
+	for (i = 0; i < hist_data->n_save_vars; i++) {
+		ret = field_var_debug_show(m, hist_data->save_vars[i], i, true);
+		if (ret)
+			goto out;
+	}
+out:
+	return ret;
+}
+
+static void hist_trigger_debug_show(struct seq_file *m,
+				    struct event_trigger_data *data, int n)
+{
+	struct hist_trigger_data *hist_data;
+	int i, ret;
+
+	if (n > 0)
+		seq_puts(m, "\n\n");
+
+	seq_puts(m, "# event histogram\n#\n# trigger info: ");
+	data->ops->print(m, data);
+	seq_puts(m, "#\n\n");
+
+	hist_data = data->private_data;
+
+	seq_printf(m, "hist_data: %p\n\n", hist_data);
+	seq_printf(m, "  n_vals: %u\n", hist_data->n_vals);
+	seq_printf(m, "  n_keys: %u\n", hist_data->n_keys);
+	seq_printf(m, "  n_fields: %u\n", hist_data->n_fields);
+
+	seq_puts(m, "\n  val fields:\n\n");
+
+	seq_puts(m, "    hist_data->fields[0]:\n");
+	ret = hist_field_debug_show(m, hist_data->fields[0],
+				    HIST_FIELD_FL_HITCOUNT);
+	if (ret)
+		return;
+
+	for (i = 1; i < hist_data->n_vals; i++) {
+		seq_printf(m, "\n    hist_data->fields[%d]:\n", i);
+		ret = hist_field_debug_show(m, hist_data->fields[i], 0);
+		if (ret)
+			return;
+	}
+
+	seq_puts(m, "\n  key fields:\n");
+
+	for (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
+		seq_printf(m, "\n    hist_data->fields[%d]:\n", i);
+		ret = hist_field_debug_show(m, hist_data->fields[i],
+					    HIST_FIELD_FL_KEY);
+		if (ret)
+			return;
+	}
+
+	if (hist_data->n_var_refs)
+		seq_puts(m, "\n  variable reference fields:\n");
+
+	for (i = 0; i < hist_data->n_var_refs; i++) {
+		seq_printf(m, "\n    hist_data->var_refs[%d]:\n", i);
+		ret = hist_field_debug_show(m, hist_data->var_refs[i],
+					    HIST_FIELD_FL_VAR_REF);
+		if (ret)
+			return;
+	}
+
+	if (hist_data->n_field_vars)
+		seq_puts(m, "\n  field variables:\n");
+
+	for (i = 0; i < hist_data->n_field_vars; i++) {
+		ret = field_var_debug_show(m, hist_data->field_vars[i], i, false);
+		if (ret)
+			return;
+	}
+
+	ret = hist_actions_debug_show(m, hist_data);
+	if (ret)
+		return;
+}
+
+static int hist_debug_show(struct seq_file *m, void *v)
+{
+	struct event_trigger_data *data;
+	struct trace_event_file *event_file;
+	int n = 0, ret = 0;
+
+	mutex_lock(&event_mutex);
+
+	event_file = event_file_data(m->private);
+	if (unlikely(!event_file)) {
+		ret = -ENODEV;
+		goto out_unlock;
+	}
+
+	list_for_each_entry(data, &event_file->triggers, list) {
+		if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
+			hist_trigger_debug_show(m, data, n++);
+	}
+
+ out_unlock:
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+static int event_hist_debug_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = tracing_open_file_tr(inode, file);
+	if (ret)
+		return ret;
+
+	/* Clear private_data to avoid warning in single_open() */
+	file->private_data = NULL;
+	return single_open(file, hist_debug_show, file);
+}
+
+const struct file_operations event_hist_debug_fops = {
+	.open = event_hist_debug_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = tracing_single_release_file_tr,
+};
+#endif
+
+static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
+{
+	const char *field_name = hist_field_name(hist_field, 0);
+
+	if (hist_field->var.name)
+		seq_printf(m, "%s=", hist_field->var.name);
+
+	if (hist_field->flags & HIST_FIELD_FL_CPU)
+		seq_puts(m, "common_cpu");
+	else if (hist_field->flags & HIST_FIELD_FL_CONST)
+		seq_printf(m, "%llu", hist_field->constant);
+	else if (field_name) {
+		if (hist_field->flags & HIST_FIELD_FL_VAR_REF ||
+		    hist_field->flags & HIST_FIELD_FL_ALIAS)
+			seq_putc(m, '$');
+		seq_printf(m, "%s", field_name);
+	} else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)
+		seq_puts(m, "common_timestamp");
+
+	if (hist_field->flags) {
+		if (!(hist_field->flags & HIST_FIELD_FL_VAR_REF) &&
+		    !(hist_field->flags & HIST_FIELD_FL_EXPR)) {
+			const char *flags = get_hist_field_flags(hist_field);
+
+			if (flags)
+				seq_printf(m, ".%s", flags);
+		}
+	}
+	if (hist_field->buckets)
+		seq_printf(m, "=%ld", hist_field->buckets);
+}
+
+static int event_hist_trigger_print(struct seq_file *m,
+				    struct event_trigger_data *data)
+{
+	struct hist_trigger_data *hist_data = data->private_data;
+	struct hist_field *field;
+	bool have_var = false;
+	unsigned int i;
+
+	seq_puts(m, HIST_PREFIX);
+
+	if (data->name)
+		seq_printf(m, "%s:", data->name);
+
+	seq_puts(m, "keys=");
+
+	for_each_hist_key_field(i, hist_data) {
+		field = hist_data->fields[i];
+
+		if (i > hist_data->n_vals)
+			seq_puts(m, ",");
+
+		if (field->flags & HIST_FIELD_FL_STACKTRACE)
+			seq_puts(m, "stacktrace");
+		else
+			hist_field_print(m, field);
+	}
+
+	seq_puts(m, ":vals=");
+
+	for_each_hist_val_field(i, hist_data) {
+		field = hist_data->fields[i];
+		if (field->flags & HIST_FIELD_FL_VAR) {
+			have_var = true;
+			continue;
+		}
+
+		if (i == HITCOUNT_IDX)
+			seq_puts(m, "hitcount");
+		else {
+			seq_puts(m, ",");
+			hist_field_print(m, field);
+		}
+	}
+
+	if (have_var) {
+		unsigned int n = 0;
+
+		seq_puts(m, ":");
+
+		for_each_hist_val_field(i, hist_data) {
+			field = hist_data->fields[i];
+
+			if (field->flags & HIST_FIELD_FL_VAR) {
+				if (n++)
+					seq_puts(m, ",");
+				hist_field_print(m, field);
+			}
+		}
+	}
+
+	seq_puts(m, ":sort=");
+
+	for (i = 0; i < hist_data->n_sort_keys; i++) {
+		struct tracing_map_sort_key *sort_key;
+		unsigned int idx, first_key_idx;
+
+		/* skip VAR vals */
+		first_key_idx = hist_data->n_vals - hist_data->n_vars;
+
+		sort_key = &hist_data->sort_keys[i];
+		idx = sort_key->field_idx;
+
+		if (WARN_ON(idx >= HIST_FIELDS_MAX))
+			return -EINVAL;
+
+		if (i > 0)
+			seq_puts(m, ",");
+
+		if (idx == HITCOUNT_IDX)
+			seq_puts(m, "hitcount");
+		else {
+			if (idx >= first_key_idx)
+				idx += hist_data->n_vars;
+			hist_field_print(m, hist_data->fields[idx]);
+		}
+
+		if (sort_key->descending)
+			seq_puts(m, ".descending");
+	}
+	seq_printf(m, ":size=%u", (1 << hist_data->map->map_bits));
+	if (hist_data->enable_timestamps)
+		seq_printf(m, ":clock=%s", hist_data->attrs->clock);
+
+	print_actions_spec(m, hist_data);
+
+	if (data->filter_str)
+		seq_printf(m, " if %s", data->filter_str);
+
+	if (data->paused)
+		seq_puts(m, " [paused]");
+	else
+		seq_puts(m, " [active]");
+
+	seq_putc(m, '\n');
+
+	return 0;
+}
+
+static int event_hist_trigger_init(struct event_trigger_data *data)
+{
+	struct hist_trigger_data *hist_data = data->private_data;
+
+	if (!data->ref && hist_data->attrs->name)
+		save_named_trigger(hist_data->attrs->name, data);
+
+	data->ref++;
+
+	return 0;
+}
+
+static void unregister_field_var_hists(struct hist_trigger_data *hist_data)
+{
+	struct trace_event_file *file;
+	unsigned int i;
+	char *cmd;
+	int ret;
+
+	for (i = 0; i < hist_data->n_field_var_hists; i++) {
+		file = hist_data->field_var_hists[i]->hist_data->event_file;
+		cmd = hist_data->field_var_hists[i]->cmd;
+		ret = event_hist_trigger_parse(&trigger_hist_cmd, file,
+					       "!hist", "hist", cmd);
+		WARN_ON_ONCE(ret < 0);
+	}
+}
+
+static void event_hist_trigger_free(struct event_trigger_data *data)
+{
+	struct hist_trigger_data *hist_data = data->private_data;
+
+	if (WARN_ON_ONCE(data->ref <= 0))
+		return;
+
+	data->ref--;
+	if (!data->ref) {
+		if (data->name)
+			del_named_trigger(data);
+
+		trigger_data_free(data);
+
+		remove_hist_vars(hist_data);
+
+		unregister_field_var_hists(hist_data);
+
+		destroy_hist_data(hist_data);
+	}
+}
+
+static struct event_trigger_ops event_hist_trigger_ops = {
+	.trigger		= event_hist_trigger,
+	.print			= event_hist_trigger_print,
+	.init			= event_hist_trigger_init,
+	.free			= event_hist_trigger_free,
+};
+
+static int event_hist_trigger_named_init(struct event_trigger_data *data)
+{
+	data->ref++;
+
+	save_named_trigger(data->named_data->name, data);
+
+	event_hist_trigger_init(data->named_data);
+
+	return 0;
+}
+
+static void event_hist_trigger_named_free(struct event_trigger_data *data)
+{
+	if (WARN_ON_ONCE(data->ref <= 0))
+		return;
+
+	event_hist_trigger_free(data->named_data);
+
+	data->ref--;
+	if (!data->ref) {
+		del_named_trigger(data);
+		trigger_data_free(data);
+	}
+}
+
+static struct event_trigger_ops event_hist_trigger_named_ops = {
+	.trigger		= event_hist_trigger,
+	.print			= event_hist_trigger_print,
+	.init			= event_hist_trigger_named_init,
+	.free			= event_hist_trigger_named_free,
+};
+
+static struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
+							    char *param)
+{
+	return &event_hist_trigger_ops;
+}
+
+static void hist_clear(struct event_trigger_data *data)
+{
+	struct hist_trigger_data *hist_data = data->private_data;
+
+	if (data->name)
+		pause_named_trigger(data);
+
+	tracepoint_synchronize_unregister();
+
+	tracing_map_clear(hist_data->map);
+
+	if (data->name)
+		unpause_named_trigger(data);
+}
+
+static bool compatible_field(struct ftrace_event_field *field,
+			     struct ftrace_event_field *test_field)
+{
+	if (field == test_field)
+		return true;
+	if (field == NULL || test_field == NULL)
+		return false;
+	if (strcmp(field->name, test_field->name) != 0)
+		return false;
+	if (strcmp(field->type, test_field->type) != 0)
+		return false;
+	if (field->size != test_field->size)
+		return false;
+	if (field->is_signed != test_field->is_signed)
+		return false;
+
+	return true;
+}
+
+static bool hist_trigger_match(struct event_trigger_data *data,
+			       struct event_trigger_data *data_test,
+			       struct event_trigger_data *named_data,
+			       bool ignore_filter)
+{
+	struct tracing_map_sort_key *sort_key, *sort_key_test;
+	struct hist_trigger_data *hist_data, *hist_data_test;
+	struct hist_field *key_field, *key_field_test;
+	unsigned int i;
+
+	if (named_data && (named_data != data_test) &&
+	    (named_data != data_test->named_data))
+		return false;
+
+	if (!named_data && is_named_trigger(data_test))
+		return false;
+
+	hist_data = data->private_data;
+	hist_data_test = data_test->private_data;
+
+	if (hist_data->n_vals != hist_data_test->n_vals ||
+	    hist_data->n_fields != hist_data_test->n_fields ||
+	    hist_data->n_sort_keys != hist_data_test->n_sort_keys)
+		return false;
+
+	if (!ignore_filter) {
+		if ((data->filter_str && !data_test->filter_str) ||
+		   (!data->filter_str && data_test->filter_str))
+			return false;
+	}
+
+	for_each_hist_field(i, hist_data) {
+		key_field = hist_data->fields[i];
+		key_field_test = hist_data_test->fields[i];
+
+		if (key_field->flags != key_field_test->flags)
+			return false;
+		if (!compatible_field(key_field->field, key_field_test->field))
+			return false;
+		if (key_field->offset != key_field_test->offset)
+			return false;
+		if (key_field->size != key_field_test->size)
+			return false;
+		if (key_field->is_signed != key_field_test->is_signed)
+			return false;
+		if (!!key_field->var.name != !!key_field_test->var.name)
+			return false;
+		if (key_field->var.name &&
+		    strcmp(key_field->var.name, key_field_test->var.name) != 0)
+			return false;
+	}
+
+	for (i = 0; i < hist_data->n_sort_keys; i++) {
+		sort_key = &hist_data->sort_keys[i];
+		sort_key_test = &hist_data_test->sort_keys[i];
+
+		if (sort_key->field_idx != sort_key_test->field_idx ||
+		    sort_key->descending != sort_key_test->descending)
+			return false;
+	}
+
+	if (!ignore_filter && data->filter_str &&
+	    (strcmp(data->filter_str, data_test->filter_str) != 0))
+		return false;
+
+	if (!actions_match(hist_data, hist_data_test))
+		return false;
+
+	return true;
+}
+
+static bool existing_hist_update_only(char *glob,
+				      struct event_trigger_data *data,
+				      struct trace_event_file *file)
+{
+	struct hist_trigger_data *hist_data = data->private_data;
+	struct event_trigger_data *test, *named_data = NULL;
+	bool updated = false;
+
+	if (!hist_data->attrs->pause && !hist_data->attrs->cont &&
+	    !hist_data->attrs->clear)
+		goto out;
+
+	if (hist_data->attrs->name) {
+		named_data = find_named_trigger(hist_data->attrs->name);
+		if (named_data) {
+			if (!hist_trigger_match(data, named_data, named_data,
+						true))
+				goto out;
+		}
+	}
+
+	if (hist_data->attrs->name && !named_data)
+		goto out;
+
+	list_for_each_entry(test, &file->triggers, list) {
+		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+			if (!hist_trigger_match(data, test, named_data, false))
+				continue;
+			if (hist_data->attrs->pause)
+				test->paused = true;
+			else if (hist_data->attrs->cont)
+				test->paused = false;
+			else if (hist_data->attrs->clear)
+				hist_clear(test);
+			updated = true;
+			goto out;
+		}
+	}
+ out:
+	return updated;
+}
+
+static int hist_register_trigger(char *glob,
+				 struct event_trigger_data *data,
+				 struct trace_event_file *file)
+{
+	struct hist_trigger_data *hist_data = data->private_data;
+	struct event_trigger_data *test, *named_data = NULL;
+	struct trace_array *tr = file->tr;
+	int ret = 0;
+
+	if (hist_data->attrs->name) {
+		named_data = find_named_trigger(hist_data->attrs->name);
+		if (named_data) {
+			if (!hist_trigger_match(data, named_data, named_data,
+						true)) {
+				hist_err(tr, HIST_ERR_NAMED_MISMATCH, errpos(hist_data->attrs->name));
+				ret = -EINVAL;
+				goto out;
+			}
+		}
+	}
+
+	if (hist_data->attrs->name && !named_data)
+		goto new;
+
+	lockdep_assert_held(&event_mutex);
+
+	list_for_each_entry(test, &file->triggers, list) {
+		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+			if (hist_trigger_match(data, test, named_data, false)) {
+				hist_err(tr, HIST_ERR_TRIGGER_EEXIST, 0);
+				ret = -EEXIST;
+				goto out;
+			}
+		}
+	}
+ new:
+	if (hist_data->attrs->cont || hist_data->attrs->clear) {
+		hist_err(tr, HIST_ERR_TRIGGER_ENOENT_CLEAR, 0);
+		ret = -ENOENT;
+		goto out;
+	}
+
+	if (hist_data->attrs->pause)
+		data->paused = true;
+
+	if (named_data) {
+		data->private_data = named_data->private_data;
+		set_named_trigger_data(data, named_data);
+		data->ops = &event_hist_trigger_named_ops;
+	}
+
+	if (data->ops->init) {
+		ret = data->ops->init(data);
+		if (ret < 0)
+			goto out;
+	}
+
+	if (hist_data->enable_timestamps) {
+		char *clock = hist_data->attrs->clock;
+
+		ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
+		if (ret) {
+			hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock));
+			goto out;
+		}
+
+		tracing_set_filter_buffering(file->tr, true);
+	}
+
+	if (named_data)
+		destroy_hist_data(hist_data);
+ out:
+	return ret;
+}
+
+static int hist_trigger_enable(struct event_trigger_data *data,
+			       struct trace_event_file *file)
+{
+	int ret = 0;
+
+	list_add_tail_rcu(&data->list, &file->triggers);
+
+	update_cond_flag(file);
+
+	if (trace_event_trigger_enable_disable(file, 1) < 0) {
+		list_del_rcu(&data->list);
+		update_cond_flag(file);
+		ret--;
+	}
+
+	return ret;
+}
+
+static bool have_hist_trigger_match(struct event_trigger_data *data,
+				    struct trace_event_file *file)
+{
+	struct hist_trigger_data *hist_data = data->private_data;
+	struct event_trigger_data *test, *named_data = NULL;
+	bool match = false;
+
+	lockdep_assert_held(&event_mutex);
+
+	if (hist_data->attrs->name)
+		named_data = find_named_trigger(hist_data->attrs->name);
+
+	list_for_each_entry(test, &file->triggers, list) {
+		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+			if (hist_trigger_match(data, test, named_data, false)) {
+				match = true;
+				break;
+			}
+		}
+	}
+
+	return match;
+}
+
+static bool hist_trigger_check_refs(struct event_trigger_data *data,
+				    struct trace_event_file *file)
+{
+	struct hist_trigger_data *hist_data = data->private_data;
+	struct event_trigger_data *test, *named_data = NULL;
+
+	lockdep_assert_held(&event_mutex);
+
+	if (hist_data->attrs->name)
+		named_data = find_named_trigger(hist_data->attrs->name);
+
+	list_for_each_entry(test, &file->triggers, list) {
+		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+			if (!hist_trigger_match(data, test, named_data, false))
+				continue;
+			hist_data = test->private_data;
+			if (check_var_refs(hist_data))
+				return true;
+			break;
+		}
+	}
+
+	return false;
+}
+
+static void hist_unregister_trigger(char *glob,
+				    struct event_trigger_data *data,
+				    struct trace_event_file *file)
+{
+	struct event_trigger_data *test = NULL, *iter, *named_data = NULL;
+	struct hist_trigger_data *hist_data = data->private_data;
+
+	lockdep_assert_held(&event_mutex);
+
+	if (hist_data->attrs->name)
+		named_data = find_named_trigger(hist_data->attrs->name);
+
+	list_for_each_entry(iter, &file->triggers, list) {
+		if (iter->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+			if (!hist_trigger_match(data, iter, named_data, false))
+				continue;
+			test = iter;
+			list_del_rcu(&test->list);
+			trace_event_trigger_enable_disable(file, 0);
+			update_cond_flag(file);
+			break;
+		}
+	}
+
+	if (test && test->ops->free)
+		test->ops->free(test);
+
+	if (hist_data->enable_timestamps) {
+		if (!hist_data->remove || test)
+			tracing_set_filter_buffering(file->tr, false);
+	}
+}
+
+static bool hist_file_check_refs(struct trace_event_file *file)
+{
+	struct hist_trigger_data *hist_data;
+	struct event_trigger_data *test;
+
+	lockdep_assert_held(&event_mutex);
+
+	list_for_each_entry(test, &file->triggers, list) {
+		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+			hist_data = test->private_data;
+			if (check_var_refs(hist_data))
+				return true;
+		}
+	}
+
+	return false;
+}
+
+static void hist_unreg_all(struct trace_event_file *file)
+{
+	struct event_trigger_data *test, *n;
+	struct hist_trigger_data *hist_data;
+	struct synth_event *se;
+	const char *se_name;
+
+	lockdep_assert_held(&event_mutex);
+
+	if (hist_file_check_refs(file))
+		return;
+
+	list_for_each_entry_safe(test, n, &file->triggers, list) {
+		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+			hist_data = test->private_data;
+			list_del_rcu(&test->list);
+			trace_event_trigger_enable_disable(file, 0);
+
+			se_name = trace_event_name(file->event_call);
+			se = find_synth_event(se_name);
+			if (se)
+				se->ref--;
+
+			update_cond_flag(file);
+			if (hist_data->enable_timestamps)
+				tracing_set_filter_buffering(file->tr, false);
+			if (test->ops->free)
+				test->ops->free(test);
+		}
+	}
+}
+
+static int event_hist_trigger_parse(struct event_command *cmd_ops,
+				    struct trace_event_file *file,
+				    char *glob, char *cmd,
+				    char *param_and_filter)
+{
+	unsigned int hist_trigger_bits = TRACING_MAP_BITS_DEFAULT;
+	struct event_trigger_data *trigger_data;
+	struct hist_trigger_attrs *attrs;
+	struct hist_trigger_data *hist_data;
+	char *param, *filter, *p, *start;
+	struct synth_event *se;
+	const char *se_name;
+	bool remove;
+	int ret = 0;
+
+	lockdep_assert_held(&event_mutex);
+
+	if (WARN_ON(!glob))
+		return -EINVAL;
+
+	if (glob[0]) {
+		hist_err_clear();
+		last_cmd_set(file, param_and_filter);
+	}
+
+	remove = event_trigger_check_remove(glob);
+
+	if (event_trigger_empty_param(param_and_filter))
+		return -EINVAL;
+
+	/*
+	 * separate the trigger from the filter (k:v [if filter])
+	 * allowing for whitespace in the trigger
+	 */
+	p = param = param_and_filter;
+	do {
+		p = strstr(p, "if");
+		if (!p)
+			break;
+		if (p == param_and_filter)
+			return -EINVAL;
+		if (*(p - 1) != ' ' && *(p - 1) != '\t') {
+			p++;
+			continue;
+		}
+		if (p >= param_and_filter + strlen(param_and_filter) - (sizeof("if") - 1) - 1)
+			return -EINVAL;
+		if (*(p + sizeof("if") - 1) != ' ' && *(p + sizeof("if") - 1) != '\t') {
+			p++;
+			continue;
+		}
+		break;
+	} while (1);
+
+	if (!p)
+		filter = NULL;
+	else {
+		*(p - 1) = '\0';
+		filter = strstrip(p);
+		param = strstrip(param);
+	}
+
+	/*
+	 * To simplify arithmetic expression parsing, replace occurrences of
+	 * '.sym-offset' modifier with '.symXoffset'
+	 */
+	start = strstr(param, ".sym-offset");
+	while (start) {
+		*(start + 4) = 'X';
+		start = strstr(start + 11, ".sym-offset");
+	}
+
+	attrs = parse_hist_trigger_attrs(file->tr, param);
+	if (IS_ERR(attrs))
+		return PTR_ERR(attrs);
+
+	if (attrs->map_bits)
+		hist_trigger_bits = attrs->map_bits;
+
+	hist_data = create_hist_data(hist_trigger_bits, attrs, file, remove);
+	if (IS_ERR(hist_data)) {
+		destroy_hist_trigger_attrs(attrs);
+		return PTR_ERR(hist_data);
+	}
+
+	trigger_data = event_trigger_alloc(cmd_ops, cmd, param, hist_data);
+	if (!trigger_data) {
+		ret = -ENOMEM;
+		goto out_free;
+	}
+
+	ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
+	if (ret < 0)
+		goto out_free;
+
+	if (remove) {
+		if (!have_hist_trigger_match(trigger_data, file))
+			goto out_free;
+
+		if (hist_trigger_check_refs(trigger_data, file)) {
+			ret = -EBUSY;
+			goto out_free;
+		}
+
+		event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
+		se_name = trace_event_name(file->event_call);
+		se = find_synth_event(se_name);
+		if (se)
+			se->ref--;
+		ret = 0;
+		goto out_free;
+	}
+
+	if (existing_hist_update_only(glob, trigger_data, file))
+		goto out_free;
+
+	ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
+	if (ret < 0)
+		goto out_free;
+
+	if (get_named_trigger_data(trigger_data))
+		goto enable;
+
+	ret = create_actions(hist_data);
+	if (ret)
+		goto out_unreg;
+
+	if (has_hist_vars(hist_data) || hist_data->n_var_refs) {
+		ret = save_hist_vars(hist_data);
+		if (ret)
+			goto out_unreg;
+	}
+
+	ret = tracing_map_init(hist_data->map);
+	if (ret)
+		goto out_unreg;
+enable:
+	ret = hist_trigger_enable(trigger_data, file);
+	if (ret)
+		goto out_unreg;
+
+	se_name = trace_event_name(file->event_call);
+	se = find_synth_event(se_name);
+	if (se)
+		se->ref++;
+ out:
+	if (ret == 0 && glob[0])
+		hist_err_clear();
+
+	return ret;
+ out_unreg:
+	event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
+ out_free:
+	event_trigger_reset_filter(cmd_ops, trigger_data);
+
+	remove_hist_vars(hist_data);
+
+	kfree(trigger_data);
+
+	destroy_hist_data(hist_data);
+	goto out;
+}
+
+static struct event_command trigger_hist_cmd = {
+	.name			= "hist",
+	.trigger_type		= ETT_EVENT_HIST,
+	.flags			= EVENT_CMD_FL_NEEDS_REC,
+	.parse			= event_hist_trigger_parse,
+	.reg			= hist_register_trigger,
+	.unreg			= hist_unregister_trigger,
+	.unreg_all		= hist_unreg_all,
+	.get_trigger_ops	= event_hist_get_trigger_ops,
+	.set_filter		= set_trigger_filter,
+};
+
+__init int register_trigger_hist_cmd(void)
+{
+	int ret;
+
+	ret = register_event_command(&trigger_hist_cmd);
+	WARN_ON(ret < 0);
+
+	return ret;
+}
+
+static void
+hist_enable_trigger(struct event_trigger_data *data,
+		    struct trace_buffer *buffer,  void *rec,
+		    struct ring_buffer_event *event)
+{
+	struct enable_trigger_data *enable_data = data->private_data;
+	struct event_trigger_data *test;
+
+	list_for_each_entry_rcu(test, &enable_data->file->triggers, list,
+				lockdep_is_held(&event_mutex)) {
+		if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+			if (enable_data->enable)
+				test->paused = false;
+			else
+				test->paused = true;
+		}
+	}
+}
+
+static void
+hist_enable_count_trigger(struct event_trigger_data *data,
+			  struct trace_buffer *buffer,  void *rec,
+			  struct ring_buffer_event *event)
+{
+	if (!data->count)
+		return;
+
+	if (data->count != -1)
+		(data->count)--;
+
+	hist_enable_trigger(data, buffer, rec, event);
+}
+
+static struct event_trigger_ops hist_enable_trigger_ops = {
+	.trigger		= hist_enable_trigger,
+	.print			= event_enable_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_enable_trigger_free,
+};
+
+static struct event_trigger_ops hist_enable_count_trigger_ops = {
+	.trigger		= hist_enable_count_trigger,
+	.print			= event_enable_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_enable_trigger_free,
+};
+
+static struct event_trigger_ops hist_disable_trigger_ops = {
+	.trigger		= hist_enable_trigger,
+	.print			= event_enable_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_enable_trigger_free,
+};
+
+static struct event_trigger_ops hist_disable_count_trigger_ops = {
+	.trigger		= hist_enable_count_trigger,
+	.print			= event_enable_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_enable_trigger_free,
+};
+
+static struct event_trigger_ops *
+hist_enable_get_trigger_ops(char *cmd, char *param)
+{
+	struct event_trigger_ops *ops;
+	bool enable;
+
+	enable = (strcmp(cmd, ENABLE_HIST_STR) == 0);
+
+	if (enable)
+		ops = param ? &hist_enable_count_trigger_ops :
+			&hist_enable_trigger_ops;
+	else
+		ops = param ? &hist_disable_count_trigger_ops :
+			&hist_disable_trigger_ops;
+
+	return ops;
+}
+
+static void hist_enable_unreg_all(struct trace_event_file *file)
+{
+	struct event_trigger_data *test, *n;
+
+	list_for_each_entry_safe(test, n, &file->triggers, list) {
+		if (test->cmd_ops->trigger_type == ETT_HIST_ENABLE) {
+			list_del_rcu(&test->list);
+			update_cond_flag(file);
+			trace_event_trigger_enable_disable(file, 0);
+			if (test->ops->free)
+				test->ops->free(test);
+		}
+	}
+}
+
+static struct event_command trigger_hist_enable_cmd = {
+	.name			= ENABLE_HIST_STR,
+	.trigger_type		= ETT_HIST_ENABLE,
+	.parse			= event_enable_trigger_parse,
+	.reg			= event_enable_register_trigger,
+	.unreg			= event_enable_unregister_trigger,
+	.unreg_all		= hist_enable_unreg_all,
+	.get_trigger_ops	= hist_enable_get_trigger_ops,
+	.set_filter		= set_trigger_filter,
+};
+
+static struct event_command trigger_hist_disable_cmd = {
+	.name			= DISABLE_HIST_STR,
+	.trigger_type		= ETT_HIST_ENABLE,
+	.parse			= event_enable_trigger_parse,
+	.reg			= event_enable_register_trigger,
+	.unreg			= event_enable_unregister_trigger,
+	.unreg_all		= hist_enable_unreg_all,
+	.get_trigger_ops	= hist_enable_get_trigger_ops,
+	.set_filter		= set_trigger_filter,
+};
+
+static __init void unregister_trigger_hist_enable_disable_cmds(void)
+{
+	unregister_event_command(&trigger_hist_enable_cmd);
+	unregister_event_command(&trigger_hist_disable_cmd);
+}
+
+__init int register_trigger_hist_enable_disable_cmds(void)
+{
+	int ret;
+
+	ret = register_event_command(&trigger_hist_enable_cmd);
+	if (WARN_ON(ret < 0))
+		return ret;
+	ret = register_event_command(&trigger_hist_disable_cmd);
+	if (WARN_ON(ret < 0))
+		unregister_trigger_hist_enable_disable_cmds();
+
+	return ret;
+}
diff --git a/kernel/trace/trace_events_inject.c b/kernel/trace/trace_events_inject.c
new file mode 100644
index 000000000..dbecfbb73
--- /dev/null
+++ b/kernel/trace/trace_events_inject.c
@@ -0,0 +1,335 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_events_inject - trace event injection
+ *
+ * Copyright (C) 2019 Cong Wang <cwang@twitter.com>
+ */
+
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/rculist.h>
+
+#include "trace.h"
+
+static int
+trace_inject_entry(struct trace_event_file *file, void *rec, int len)
+{
+	struct trace_event_buffer fbuffer;
+	int written = 0;
+	void *entry;
+
+	rcu_read_lock_sched();
+	entry = trace_event_buffer_reserve(&fbuffer, file, len);
+	if (entry) {
+		memcpy(entry, rec, len);
+		written = len;
+		trace_event_buffer_commit(&fbuffer);
+	}
+	rcu_read_unlock_sched();
+
+	return written;
+}
+
+static int
+parse_field(char *str, struct trace_event_call *call,
+	    struct ftrace_event_field **pf, u64 *pv)
+{
+	struct ftrace_event_field *field;
+	char *field_name;
+	int s, i = 0;
+	int len;
+	u64 val;
+
+	if (!str[i])
+		return 0;
+	/* First find the field to associate to */
+	while (isspace(str[i]))
+		i++;
+	s = i;
+	while (isalnum(str[i]) || str[i] == '_')
+		i++;
+	len = i - s;
+	if (!len)
+		return -EINVAL;
+
+	field_name = kmemdup_nul(str + s, len, GFP_KERNEL);
+	if (!field_name)
+		return -ENOMEM;
+	field = trace_find_event_field(call, field_name);
+	kfree(field_name);
+	if (!field)
+		return -ENOENT;
+
+	*pf = field;
+	while (isspace(str[i]))
+		i++;
+	if (str[i] != '=')
+		return -EINVAL;
+	i++;
+	while (isspace(str[i]))
+		i++;
+	s = i;
+	if (isdigit(str[i]) || str[i] == '-') {
+		char *num, c;
+		int ret;
+
+		/* Make sure the field is not a string */
+		if (is_string_field(field))
+			return -EINVAL;
+
+		if (str[i] == '-')
+			i++;
+
+		/* We allow 0xDEADBEEF */
+		while (isalnum(str[i]))
+			i++;
+		num = str + s;
+		c = str[i];
+		if (c != '\0' && !isspace(c))
+			return -EINVAL;
+		str[i] = '\0';
+		/* Make sure it is a value */
+		if (field->is_signed)
+			ret = kstrtoll(num, 0, &val);
+		else
+			ret = kstrtoull(num, 0, &val);
+		str[i] = c;
+		if (ret)
+			return ret;
+
+		*pv = val;
+		return i;
+	} else if (str[i] == '\'' || str[i] == '"') {
+		char q = str[i];
+
+		/* Make sure the field is OK for strings */
+		if (!is_string_field(field))
+			return -EINVAL;
+
+		for (i++; str[i]; i++) {
+			if (str[i] == '\\' && str[i + 1]) {
+				i++;
+				continue;
+			}
+			if (str[i] == q)
+				break;
+		}
+		if (!str[i])
+			return -EINVAL;
+
+		/* Skip quotes */
+		s++;
+		len = i - s;
+		if (len >= MAX_FILTER_STR_VAL)
+			return -EINVAL;
+
+		*pv = (unsigned long)(str + s);
+		str[i] = 0;
+		/* go past the last quote */
+		i++;
+		return i;
+	}
+
+	return -EINVAL;
+}
+
+static int trace_get_entry_size(struct trace_event_call *call)
+{
+	struct ftrace_event_field *field;
+	struct list_head *head;
+	int size = 0;
+
+	head = trace_get_fields(call);
+	list_for_each_entry(field, head, link) {
+		if (field->size + field->offset > size)
+			size = field->size + field->offset;
+	}
+
+	return size;
+}
+
+static void *trace_alloc_entry(struct trace_event_call *call, int *size)
+{
+	int entry_size = trace_get_entry_size(call);
+	struct ftrace_event_field *field;
+	struct list_head *head;
+	void *entry = NULL;
+
+	/* We need an extra '\0' at the end. */
+	entry = kzalloc(entry_size + 1, GFP_KERNEL);
+	if (!entry)
+		return NULL;
+
+	head = trace_get_fields(call);
+	list_for_each_entry(field, head, link) {
+		if (!is_string_field(field))
+			continue;
+		if (field->filter_type == FILTER_STATIC_STRING)
+			continue;
+		if (field->filter_type == FILTER_DYN_STRING ||
+		    field->filter_type == FILTER_RDYN_STRING) {
+			u32 *str_item;
+			int str_loc = entry_size & 0xffff;
+
+			if (field->filter_type == FILTER_RDYN_STRING)
+				str_loc -= field->offset + field->size;
+
+			str_item = (u32 *)(entry + field->offset);
+			*str_item = str_loc; /* string length is 0. */
+		} else {
+			char **paddr;
+
+			paddr = (char **)(entry + field->offset);
+			*paddr = "";
+		}
+	}
+
+	*size = entry_size + 1;
+	return entry;
+}
+
+#define INJECT_STRING "STATIC STRING CAN NOT BE INJECTED"
+
+/* Caller is responsible to free the *pentry. */
+static int parse_entry(char *str, struct trace_event_call *call, void **pentry)
+{
+	struct ftrace_event_field *field;
+	void *entry = NULL;
+	int entry_size;
+	u64 val = 0;
+	int len;
+
+	entry = trace_alloc_entry(call, &entry_size);
+	*pentry = entry;
+	if (!entry)
+		return -ENOMEM;
+
+	tracing_generic_entry_update(entry, call->event.type,
+				     tracing_gen_ctx());
+
+	while ((len = parse_field(str, call, &field, &val)) > 0) {
+		if (is_function_field(field))
+			return -EINVAL;
+
+		if (is_string_field(field)) {
+			char *addr = (char *)(unsigned long) val;
+
+			if (field->filter_type == FILTER_STATIC_STRING) {
+				strlcpy(entry + field->offset, addr, field->size);
+			} else if (field->filter_type == FILTER_DYN_STRING ||
+				   field->filter_type == FILTER_RDYN_STRING) {
+				int str_len = strlen(addr) + 1;
+				int str_loc = entry_size & 0xffff;
+				u32 *str_item;
+
+				entry_size += str_len;
+				*pentry = krealloc(entry, entry_size, GFP_KERNEL);
+				if (!*pentry) {
+					kfree(entry);
+					return -ENOMEM;
+				}
+				entry = *pentry;
+
+				strlcpy(entry + (entry_size - str_len), addr, str_len);
+				str_item = (u32 *)(entry + field->offset);
+				if (field->filter_type == FILTER_RDYN_STRING)
+					str_loc -= field->offset + field->size;
+				*str_item = (str_len << 16) | str_loc;
+			} else {
+				char **paddr;
+
+				paddr = (char **)(entry + field->offset);
+				*paddr = INJECT_STRING;
+			}
+		} else {
+			switch (field->size) {
+			case 1: {
+				u8 tmp = (u8) val;
+
+				memcpy(entry + field->offset, &tmp, 1);
+				break;
+			}
+			case 2: {
+				u16 tmp = (u16) val;
+
+				memcpy(entry + field->offset, &tmp, 2);
+				break;
+			}
+			case 4: {
+				u32 tmp = (u32) val;
+
+				memcpy(entry + field->offset, &tmp, 4);
+				break;
+			}
+			case 8:
+				memcpy(entry + field->offset, &val, 8);
+				break;
+			default:
+				return -EINVAL;
+			}
+		}
+
+		str += len;
+	}
+
+	if (len < 0)
+		return len;
+
+	return entry_size;
+}
+
+static ssize_t
+event_inject_write(struct file *filp, const char __user *ubuf, size_t cnt,
+		   loff_t *ppos)
+{
+	struct trace_event_call *call;
+	struct trace_event_file *file;
+	int err = -ENODEV, size;
+	void *entry = NULL;
+	char *buf;
+
+	if (cnt >= PAGE_SIZE)
+		return -EINVAL;
+
+	buf = memdup_user_nul(ubuf, cnt);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+	strim(buf);
+
+	mutex_lock(&event_mutex);
+	file = event_file_data(filp);
+	if (file) {
+		call = file->event_call;
+		size = parse_entry(buf, call, &entry);
+		if (size < 0)
+			err = size;
+		else
+			err = trace_inject_entry(file, entry, size);
+	}
+	mutex_unlock(&event_mutex);
+
+	kfree(entry);
+	kfree(buf);
+
+	if (err < 0)
+		return err;
+
+	*ppos += err;
+	return cnt;
+}
+
+static ssize_t
+event_inject_read(struct file *file, char __user *buf, size_t size,
+		  loff_t *ppos)
+{
+	return -EPERM;
+}
+
+const struct file_operations event_inject_fops = {
+	.open = tracing_open_file_tr,
+	.read = event_inject_read,
+	.write = event_inject_write,
+	.release = tracing_release_file_tr,
+};
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
new file mode 100644
index 000000000..94a2e9d21
--- /dev/null
+++ b/kernel/trace/trace_events_synth.c
@@ -0,0 +1,2351 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_events_synth - synthetic trace events
+ *
+ * Copyright (C) 2015, 2020 Tom Zanussi <tom.zanussi@linux.intel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/security.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/stacktrace.h>
+#include <linux/rculist.h>
+#include <linux/tracefs.h>
+
+/* for gfp flag names */
+#include <linux/trace_events.h>
+#include <trace/events/mmflags.h>
+#include "trace_probe.h"
+#include "trace_probe_kernel.h"
+
+#include "trace_synth.h"
+
+#undef ERRORS
+#define ERRORS	\
+	C(BAD_NAME,		"Illegal name"),		\
+	C(INVALID_CMD,		"Command must be of the form: <name> field[;field] ..."),\
+	C(INVALID_DYN_CMD,	"Command must be of the form: s or -:[synthetic/]<name> field[;field] ..."),\
+	C(EVENT_EXISTS,		"Event already exists"),	\
+	C(TOO_MANY_FIELDS,	"Too many fields"),		\
+	C(INCOMPLETE_TYPE,	"Incomplete type"),		\
+	C(INVALID_TYPE,		"Invalid type"),		\
+	C(INVALID_FIELD,        "Invalid field"),		\
+	C(INVALID_ARRAY_SPEC,	"Invalid array specification"),
+
+#undef C
+#define C(a, b)		SYNTH_ERR_##a
+
+enum { ERRORS };
+
+#undef C
+#define C(a, b)		b
+
+static const char *err_text[] = { ERRORS };
+
+static DEFINE_MUTEX(lastcmd_mutex);
+static char *last_cmd;
+
+static int errpos(const char *str)
+{
+	int ret = 0;
+
+	mutex_lock(&lastcmd_mutex);
+	if (!str || !last_cmd)
+		goto out;
+
+	ret = err_pos(last_cmd, str);
+ out:
+	mutex_unlock(&lastcmd_mutex);
+	return ret;
+}
+
+static void last_cmd_set(const char *str)
+{
+	if (!str)
+		return;
+
+	mutex_lock(&lastcmd_mutex);
+	kfree(last_cmd);
+	last_cmd = kstrdup(str, GFP_KERNEL);
+	mutex_unlock(&lastcmd_mutex);
+}
+
+static void synth_err(u8 err_type, u16 err_pos)
+{
+	mutex_lock(&lastcmd_mutex);
+	if (!last_cmd)
+		goto out;
+
+	tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
+			err_type, err_pos);
+ out:
+	mutex_unlock(&lastcmd_mutex);
+}
+
+static int create_synth_event(const char *raw_command);
+static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
+static int synth_event_release(struct dyn_event *ev);
+static bool synth_event_is_busy(struct dyn_event *ev);
+static bool synth_event_match(const char *system, const char *event,
+			int argc, const char **argv, struct dyn_event *ev);
+
+static struct dyn_event_operations synth_event_ops = {
+	.create = create_synth_event,
+	.show = synth_event_show,
+	.is_busy = synth_event_is_busy,
+	.free = synth_event_release,
+	.match = synth_event_match,
+};
+
+static bool is_synth_event(struct dyn_event *ev)
+{
+	return ev->ops == &synth_event_ops;
+}
+
+static struct synth_event *to_synth_event(struct dyn_event *ev)
+{
+	return container_of(ev, struct synth_event, devent);
+}
+
+static bool synth_event_is_busy(struct dyn_event *ev)
+{
+	struct synth_event *event = to_synth_event(ev);
+
+	return event->ref != 0;
+}
+
+static bool synth_event_match(const char *system, const char *event,
+			int argc, const char **argv, struct dyn_event *ev)
+{
+	struct synth_event *sev = to_synth_event(ev);
+
+	return strcmp(sev->name, event) == 0 &&
+		(!system || strcmp(system, SYNTH_SYSTEM) == 0);
+}
+
+struct synth_trace_event {
+	struct trace_entry	ent;
+	u64			fields[];
+};
+
+static int synth_event_define_fields(struct trace_event_call *call)
+{
+	struct synth_trace_event trace;
+	int offset = offsetof(typeof(trace), fields);
+	struct synth_event *event = call->data;
+	unsigned int i, size, n_u64;
+	char *name, *type;
+	bool is_signed;
+	int ret = 0;
+
+	for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
+		size = event->fields[i]->size;
+		is_signed = event->fields[i]->is_signed;
+		type = event->fields[i]->type;
+		name = event->fields[i]->name;
+		ret = trace_define_field(call, type, name, offset, size,
+					 is_signed, FILTER_OTHER);
+		if (ret)
+			break;
+
+		event->fields[i]->offset = n_u64;
+
+		if (event->fields[i]->is_string && !event->fields[i]->is_dynamic) {
+			offset += STR_VAR_LEN_MAX;
+			n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
+		} else {
+			offset += sizeof(u64);
+			n_u64++;
+		}
+	}
+
+	event->n_u64 = n_u64;
+
+	return ret;
+}
+
+static bool synth_field_signed(char *type)
+{
+	if (str_has_prefix(type, "u"))
+		return false;
+	if (strcmp(type, "gfp_t") == 0)
+		return false;
+
+	return true;
+}
+
+static int synth_field_is_string(char *type)
+{
+	if (strstr(type, "char[") != NULL)
+		return true;
+
+	return false;
+}
+
+static int synth_field_is_stack(char *type)
+{
+	if (strstr(type, "long[") != NULL)
+		return true;
+
+	return false;
+}
+
+static int synth_field_string_size(char *type)
+{
+	char buf[4], *end, *start;
+	unsigned int len;
+	int size, err;
+
+	start = strstr(type, "char[");
+	if (start == NULL)
+		return -EINVAL;
+	start += sizeof("char[") - 1;
+
+	end = strchr(type, ']');
+	if (!end || end < start || type + strlen(type) > end + 1)
+		return -EINVAL;
+
+	len = end - start;
+	if (len > 3)
+		return -EINVAL;
+
+	if (len == 0)
+		return 0; /* variable-length string */
+
+	strncpy(buf, start, len);
+	buf[len] = '\0';
+
+	err = kstrtouint(buf, 0, &size);
+	if (err)
+		return err;
+
+	if (size > STR_VAR_LEN_MAX)
+		return -EINVAL;
+
+	return size;
+}
+
+static int synth_field_size(char *type)
+{
+	int size = 0;
+
+	if (strcmp(type, "s64") == 0)
+		size = sizeof(s64);
+	else if (strcmp(type, "u64") == 0)
+		size = sizeof(u64);
+	else if (strcmp(type, "s32") == 0)
+		size = sizeof(s32);
+	else if (strcmp(type, "u32") == 0)
+		size = sizeof(u32);
+	else if (strcmp(type, "s16") == 0)
+		size = sizeof(s16);
+	else if (strcmp(type, "u16") == 0)
+		size = sizeof(u16);
+	else if (strcmp(type, "s8") == 0)
+		size = sizeof(s8);
+	else if (strcmp(type, "u8") == 0)
+		size = sizeof(u8);
+	else if (strcmp(type, "char") == 0)
+		size = sizeof(char);
+	else if (strcmp(type, "unsigned char") == 0)
+		size = sizeof(unsigned char);
+	else if (strcmp(type, "int") == 0)
+		size = sizeof(int);
+	else if (strcmp(type, "unsigned int") == 0)
+		size = sizeof(unsigned int);
+	else if (strcmp(type, "long") == 0)
+		size = sizeof(long);
+	else if (strcmp(type, "unsigned long") == 0)
+		size = sizeof(unsigned long);
+	else if (strcmp(type, "bool") == 0)
+		size = sizeof(bool);
+	else if (strcmp(type, "pid_t") == 0)
+		size = sizeof(pid_t);
+	else if (strcmp(type, "gfp_t") == 0)
+		size = sizeof(gfp_t);
+	else if (synth_field_is_string(type))
+		size = synth_field_string_size(type);
+	else if (synth_field_is_stack(type))
+		size = 0;
+
+	return size;
+}
+
+static const char *synth_field_fmt(char *type)
+{
+	const char *fmt = "%llu";
+
+	if (strcmp(type, "s64") == 0)
+		fmt = "%lld";
+	else if (strcmp(type, "u64") == 0)
+		fmt = "%llu";
+	else if (strcmp(type, "s32") == 0)
+		fmt = "%d";
+	else if (strcmp(type, "u32") == 0)
+		fmt = "%u";
+	else if (strcmp(type, "s16") == 0)
+		fmt = "%d";
+	else if (strcmp(type, "u16") == 0)
+		fmt = "%u";
+	else if (strcmp(type, "s8") == 0)
+		fmt = "%d";
+	else if (strcmp(type, "u8") == 0)
+		fmt = "%u";
+	else if (strcmp(type, "char") == 0)
+		fmt = "%d";
+	else if (strcmp(type, "unsigned char") == 0)
+		fmt = "%u";
+	else if (strcmp(type, "int") == 0)
+		fmt = "%d";
+	else if (strcmp(type, "unsigned int") == 0)
+		fmt = "%u";
+	else if (strcmp(type, "long") == 0)
+		fmt = "%ld";
+	else if (strcmp(type, "unsigned long") == 0)
+		fmt = "%lu";
+	else if (strcmp(type, "bool") == 0)
+		fmt = "%d";
+	else if (strcmp(type, "pid_t") == 0)
+		fmt = "%d";
+	else if (strcmp(type, "gfp_t") == 0)
+		fmt = "%x";
+	else if (synth_field_is_string(type))
+		fmt = "%.*s";
+	else if (synth_field_is_stack(type))
+		fmt = "%s";
+
+	return fmt;
+}
+
+static void print_synth_event_num_val(struct trace_seq *s,
+				      char *print_fmt, char *name,
+				      int size, u64 val, char *space)
+{
+	switch (size) {
+	case 1:
+		trace_seq_printf(s, print_fmt, name, (u8)val, space);
+		break;
+
+	case 2:
+		trace_seq_printf(s, print_fmt, name, (u16)val, space);
+		break;
+
+	case 4:
+		trace_seq_printf(s, print_fmt, name, (u32)val, space);
+		break;
+
+	default:
+		trace_seq_printf(s, print_fmt, name, val, space);
+		break;
+	}
+}
+
+static enum print_line_t print_synth_event(struct trace_iterator *iter,
+					   int flags,
+					   struct trace_event *event)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	struct synth_trace_event *entry;
+	struct synth_event *se;
+	unsigned int i, n_u64;
+	char print_fmt[32];
+	const char *fmt;
+
+	entry = (struct synth_trace_event *)iter->ent;
+	se = container_of(event, struct synth_event, call.event);
+
+	trace_seq_printf(s, "%s: ", se->name);
+
+	for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
+		if (trace_seq_has_overflowed(s))
+			goto end;
+
+		fmt = synth_field_fmt(se->fields[i]->type);
+
+		/* parameter types */
+		if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
+			trace_seq_printf(s, "%s ", fmt);
+
+		snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
+
+		/* parameter values */
+		if (se->fields[i]->is_string) {
+			if (se->fields[i]->is_dynamic) {
+				u32 offset, data_offset;
+				char *str_field;
+
+				offset = (u32)entry->fields[n_u64];
+				data_offset = offset & 0xffff;
+
+				str_field = (char *)entry + data_offset;
+
+				trace_seq_printf(s, print_fmt, se->fields[i]->name,
+						 STR_VAR_LEN_MAX,
+						 str_field,
+						 i == se->n_fields - 1 ? "" : " ");
+				n_u64++;
+			} else {
+				trace_seq_printf(s, print_fmt, se->fields[i]->name,
+						 STR_VAR_LEN_MAX,
+						 (char *)&entry->fields[n_u64],
+						 i == se->n_fields - 1 ? "" : " ");
+				n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
+			}
+		} else if (se->fields[i]->is_stack) {
+			u32 offset, data_offset, len;
+			unsigned long *p, *end;
+
+			offset = (u32)entry->fields[n_u64];
+			data_offset = offset & 0xffff;
+			len = offset >> 16;
+
+			p = (void *)entry + data_offset;
+			end = (void *)p + len - (sizeof(long) - 1);
+
+			trace_seq_printf(s, "%s=STACK:\n", se->fields[i]->name);
+
+			for (; *p && p < end; p++)
+				trace_seq_printf(s, "=> %pS\n", (void *)*p);
+			n_u64++;
+
+		} else {
+			struct trace_print_flags __flags[] = {
+			    __def_gfpflag_names, {-1, NULL} };
+			char *space = (i == se->n_fields - 1 ? "" : " ");
+
+			print_synth_event_num_val(s, print_fmt,
+						  se->fields[i]->name,
+						  se->fields[i]->size,
+						  entry->fields[n_u64],
+						  space);
+
+			if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
+				trace_seq_puts(s, " (");
+				trace_print_flags_seq(s, "|",
+						      entry->fields[n_u64],
+						      __flags);
+				trace_seq_putc(s, ')');
+			}
+			n_u64++;
+		}
+	}
+end:
+	trace_seq_putc(s, '\n');
+
+	return trace_handle_return(s);
+}
+
+static struct trace_event_functions synth_event_funcs = {
+	.trace		= print_synth_event
+};
+
+static unsigned int trace_string(struct synth_trace_event *entry,
+				 struct synth_event *event,
+				 char *str_val,
+				 bool is_dynamic,
+				 unsigned int data_size,
+				 unsigned int *n_u64)
+{
+	unsigned int len = 0;
+	char *str_field;
+	int ret;
+
+	if (is_dynamic) {
+		u32 data_offset;
+
+		data_offset = offsetof(typeof(*entry), fields);
+		data_offset += event->n_u64 * sizeof(u64);
+		data_offset += data_size;
+
+		len = kern_fetch_store_strlen((unsigned long)str_val);
+
+		data_offset |= len << 16;
+		*(u32 *)&entry->fields[*n_u64] = data_offset;
+
+		ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
+
+		(*n_u64)++;
+	} else {
+		str_field = (char *)&entry->fields[*n_u64];
+
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+		if ((unsigned long)str_val < TASK_SIZE)
+			ret = strncpy_from_user_nofault(str_field, (const void __user *)str_val, STR_VAR_LEN_MAX);
+		else
+#endif
+			ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX);
+
+		if (ret < 0)
+			strcpy(str_field, FAULT_STRING);
+
+		(*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
+	}
+
+	return len;
+}
+
+static unsigned int trace_stack(struct synth_trace_event *entry,
+				 struct synth_event *event,
+				 long *stack,
+				 unsigned int data_size,
+				 unsigned int *n_u64)
+{
+	unsigned int len;
+	u32 data_offset;
+	void *data_loc;
+
+	data_offset = struct_size(entry, fields, event->n_u64);
+	data_offset += data_size;
+
+	for (len = 0; len < HIST_STACKTRACE_DEPTH; len++) {
+		if (!stack[len])
+			break;
+	}
+
+	/* Include the zero'd element if it fits */
+	if (len < HIST_STACKTRACE_DEPTH)
+		len++;
+
+	len *= sizeof(long);
+
+	/* Find the dynamic section to copy the stack into. */
+	data_loc = (void *)entry + data_offset;
+	memcpy(data_loc, stack, len);
+
+	/* Fill in the field that holds the offset/len combo */
+	data_offset |= len << 16;
+	*(u32 *)&entry->fields[*n_u64] = data_offset;
+
+	(*n_u64)++;
+
+	return len;
+}
+
+static notrace void trace_event_raw_event_synth(void *__data,
+						u64 *var_ref_vals,
+						unsigned int *var_ref_idx)
+{
+	unsigned int i, n_u64, val_idx, len, data_size = 0;
+	struct trace_event_file *trace_file = __data;
+	struct synth_trace_event *entry;
+	struct trace_event_buffer fbuffer;
+	struct trace_buffer *buffer;
+	struct synth_event *event;
+	int fields_size = 0;
+
+	event = trace_file->event_call->data;
+
+	if (trace_trigger_soft_disabled(trace_file))
+		return;
+
+	fields_size = event->n_u64 * sizeof(u64);
+
+	for (i = 0; i < event->n_dynamic_fields; i++) {
+		unsigned int field_pos = event->dynamic_fields[i]->field_pos;
+		char *str_val;
+
+		val_idx = var_ref_idx[field_pos];
+		str_val = (char *)(long)var_ref_vals[val_idx];
+
+		len = kern_fetch_store_strlen((unsigned long)str_val);
+
+		fields_size += len;
+	}
+
+	/*
+	 * Avoid ring buffer recursion detection, as this event
+	 * is being performed within another event.
+	 */
+	buffer = trace_file->tr->array_buffer.buffer;
+	ring_buffer_nest_start(buffer);
+
+	entry = trace_event_buffer_reserve(&fbuffer, trace_file,
+					   sizeof(*entry) + fields_size);
+	if (!entry)
+		goto out;
+
+	for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
+		val_idx = var_ref_idx[i];
+		if (event->fields[i]->is_string) {
+			char *str_val = (char *)(long)var_ref_vals[val_idx];
+
+			len = trace_string(entry, event, str_val,
+					   event->fields[i]->is_dynamic,
+					   data_size, &n_u64);
+			data_size += len; /* only dynamic string increments */
+		} else if (event->fields[i]->is_stack) {
+			long *stack = (long *)(long)var_ref_vals[val_idx];
+
+			len = trace_stack(entry, event, stack,
+					   data_size, &n_u64);
+			data_size += len;
+		} else {
+			struct synth_field *field = event->fields[i];
+			u64 val = var_ref_vals[val_idx];
+
+			switch (field->size) {
+			case 1:
+				*(u8 *)&entry->fields[n_u64] = (u8)val;
+				break;
+
+			case 2:
+				*(u16 *)&entry->fields[n_u64] = (u16)val;
+				break;
+
+			case 4:
+				*(u32 *)&entry->fields[n_u64] = (u32)val;
+				break;
+
+			default:
+				entry->fields[n_u64] = val;
+				break;
+			}
+			n_u64++;
+		}
+	}
+
+	trace_event_buffer_commit(&fbuffer);
+out:
+	ring_buffer_nest_end(buffer);
+}
+
+static void free_synth_event_print_fmt(struct trace_event_call *call)
+{
+	if (call) {
+		kfree(call->print_fmt);
+		call->print_fmt = NULL;
+	}
+}
+
+static int __set_synth_event_print_fmt(struct synth_event *event,
+				       char *buf, int len)
+{
+	const char *fmt;
+	int pos = 0;
+	int i;
+
+	/* When len=0, we just calculate the needed length */
+#define LEN_OR_ZERO (len ? len - pos : 0)
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
+	for (i = 0; i < event->n_fields; i++) {
+		fmt = synth_field_fmt(event->fields[i]->type);
+		pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
+				event->fields[i]->name, fmt,
+				i == event->n_fields - 1 ? "" : ", ");
+	}
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
+
+	for (i = 0; i < event->n_fields; i++) {
+		if (event->fields[i]->is_string &&
+		    event->fields[i]->is_dynamic)
+			pos += snprintf(buf + pos, LEN_OR_ZERO,
+				", __get_str(%s)", event->fields[i]->name);
+		else if (event->fields[i]->is_stack)
+			pos += snprintf(buf + pos, LEN_OR_ZERO,
+				", __get_stacktrace(%s)", event->fields[i]->name);
+		else
+			pos += snprintf(buf + pos, LEN_OR_ZERO,
+					", REC->%s", event->fields[i]->name);
+	}
+
+#undef LEN_OR_ZERO
+
+	/* return the length of print_fmt */
+	return pos;
+}
+
+static int set_synth_event_print_fmt(struct trace_event_call *call)
+{
+	struct synth_event *event = call->data;
+	char *print_fmt;
+	int len;
+
+	/* First: called with 0 length to calculate the needed length */
+	len = __set_synth_event_print_fmt(event, NULL, 0);
+
+	print_fmt = kmalloc(len + 1, GFP_KERNEL);
+	if (!print_fmt)
+		return -ENOMEM;
+
+	/* Second: actually write the @print_fmt */
+	__set_synth_event_print_fmt(event, print_fmt, len + 1);
+	call->print_fmt = print_fmt;
+
+	return 0;
+}
+
+static void free_synth_field(struct synth_field *field)
+{
+	kfree(field->type);
+	kfree(field->name);
+	kfree(field);
+}
+
+static int check_field_version(const char *prefix, const char *field_type,
+			       const char *field_name)
+{
+	/*
+	 * For backward compatibility, the old synthetic event command
+	 * format did not require semicolons, and in order to not
+	 * break user space, that old format must still work. If a new
+	 * feature is added, then the format that uses the new feature
+	 * will be required to have semicolons, as nothing that uses
+	 * the old format would be using the new, yet to be created,
+	 * feature. When a new feature is added, this will detect it,
+	 * and return a number greater than 1, and require the format
+	 * to use semicolons.
+	 */
+	return 1;
+}
+
+static struct synth_field *parse_synth_field(int argc, char **argv,
+					     int *consumed, int *field_version)
+{
+	const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
+	struct synth_field *field;
+	int len, ret = -ENOMEM;
+	struct seq_buf s;
+	ssize_t size;
+
+	if (!strcmp(field_type, "unsigned")) {
+		if (argc < 3) {
+			synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
+			return ERR_PTR(-EINVAL);
+		}
+		prefix = "unsigned ";
+		field_type = argv[1];
+		field_name = argv[2];
+		*consumed += 3;
+	} else {
+		field_name = argv[1];
+		*consumed += 2;
+	}
+
+	if (!field_name) {
+		synth_err(SYNTH_ERR_INVALID_FIELD, errpos(field_type));
+		return ERR_PTR(-EINVAL);
+	}
+
+	*field_version = check_field_version(prefix, field_type, field_name);
+
+	field = kzalloc(sizeof(*field), GFP_KERNEL);
+	if (!field)
+		return ERR_PTR(-ENOMEM);
+
+	len = strlen(field_name);
+	array = strchr(field_name, '[');
+	if (array)
+		len -= strlen(array);
+
+	field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
+	if (!field->name)
+		goto free;
+
+	if (!is_good_name(field->name)) {
+		synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
+		ret = -EINVAL;
+		goto free;
+	}
+
+	len = strlen(field_type) + 1;
+
+	if (array)
+		len += strlen(array);
+
+	if (prefix)
+		len += strlen(prefix);
+
+	field->type = kzalloc(len, GFP_KERNEL);
+	if (!field->type)
+		goto free;
+
+	seq_buf_init(&s, field->type, len);
+	if (prefix)
+		seq_buf_puts(&s, prefix);
+	seq_buf_puts(&s, field_type);
+	if (array)
+		seq_buf_puts(&s, array);
+	if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
+		goto free;
+
+	s.buffer[s.len] = '\0';
+
+	size = synth_field_size(field->type);
+	if (size < 0) {
+		if (array)
+			synth_err(SYNTH_ERR_INVALID_ARRAY_SPEC, errpos(field_name));
+		else
+			synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
+		ret = -EINVAL;
+		goto free;
+	} else if (size == 0) {
+		if (synth_field_is_string(field->type) ||
+		    synth_field_is_stack(field->type)) {
+			char *type;
+
+			len = sizeof("__data_loc ") + strlen(field->type) + 1;
+			type = kzalloc(len, GFP_KERNEL);
+			if (!type)
+				goto free;
+
+			seq_buf_init(&s, type, len);
+			seq_buf_puts(&s, "__data_loc ");
+			seq_buf_puts(&s, field->type);
+
+			if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
+				goto free;
+			s.buffer[s.len] = '\0';
+
+			kfree(field->type);
+			field->type = type;
+
+			field->is_dynamic = true;
+			size = sizeof(u64);
+		} else {
+			synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
+			ret = -EINVAL;
+			goto free;
+		}
+	}
+	field->size = size;
+
+	if (synth_field_is_string(field->type))
+		field->is_string = true;
+	else if (synth_field_is_stack(field->type))
+		field->is_stack = true;
+
+	field->is_signed = synth_field_signed(field->type);
+ out:
+	return field;
+ free:
+	free_synth_field(field);
+	field = ERR_PTR(ret);
+	goto out;
+}
+
+static void free_synth_tracepoint(struct tracepoint *tp)
+{
+	if (!tp)
+		return;
+
+	kfree(tp->name);
+	kfree(tp);
+}
+
+static struct tracepoint *alloc_synth_tracepoint(char *name)
+{
+	struct tracepoint *tp;
+
+	tp = kzalloc(sizeof(*tp), GFP_KERNEL);
+	if (!tp)
+		return ERR_PTR(-ENOMEM);
+
+	tp->name = kstrdup(name, GFP_KERNEL);
+	if (!tp->name) {
+		kfree(tp);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return tp;
+}
+
+struct synth_event *find_synth_event(const char *name)
+{
+	struct dyn_event *pos;
+	struct synth_event *event;
+
+	for_each_dyn_event(pos) {
+		if (!is_synth_event(pos))
+			continue;
+		event = to_synth_event(pos);
+		if (strcmp(event->name, name) == 0)
+			return event;
+	}
+
+	return NULL;
+}
+
+static struct trace_event_fields synth_event_fields_array[] = {
+	{ .type = TRACE_FUNCTION_TYPE,
+	  .define_fields = synth_event_define_fields },
+	{}
+};
+
+static int register_synth_event(struct synth_event *event)
+{
+	struct trace_event_call *call = &event->call;
+	int ret = 0;
+
+	event->call.class = &event->class;
+	event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
+	if (!event->class.system) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	event->tp = alloc_synth_tracepoint(event->name);
+	if (IS_ERR(event->tp)) {
+		ret = PTR_ERR(event->tp);
+		event->tp = NULL;
+		goto out;
+	}
+
+	INIT_LIST_HEAD(&call->class->fields);
+	call->event.funcs = &synth_event_funcs;
+	call->class->fields_array = synth_event_fields_array;
+
+	ret = register_trace_event(&call->event);
+	if (!ret) {
+		ret = -ENODEV;
+		goto out;
+	}
+	call->flags = TRACE_EVENT_FL_TRACEPOINT;
+	call->class->reg = trace_event_reg;
+	call->class->probe = trace_event_raw_event_synth;
+	call->data = event;
+	call->tp = event->tp;
+
+	ret = trace_add_event_call(call);
+	if (ret) {
+		pr_warn("Failed to register synthetic event: %s\n",
+			trace_event_name(call));
+		goto err;
+	}
+
+	ret = set_synth_event_print_fmt(call);
+	/* unregister_trace_event() will be called inside */
+	if (ret < 0)
+		trace_remove_event_call(call);
+ out:
+	return ret;
+ err:
+	unregister_trace_event(&call->event);
+	goto out;
+}
+
+static int unregister_synth_event(struct synth_event *event)
+{
+	struct trace_event_call *call = &event->call;
+	int ret;
+
+	ret = trace_remove_event_call(call);
+
+	return ret;
+}
+
+static void free_synth_event(struct synth_event *event)
+{
+	unsigned int i;
+
+	if (!event)
+		return;
+
+	for (i = 0; i < event->n_fields; i++)
+		free_synth_field(event->fields[i]);
+
+	kfree(event->fields);
+	kfree(event->dynamic_fields);
+	kfree(event->name);
+	kfree(event->class.system);
+	free_synth_tracepoint(event->tp);
+	free_synth_event_print_fmt(&event->call);
+	kfree(event);
+}
+
+static struct synth_event *alloc_synth_event(const char *name, int n_fields,
+					     struct synth_field **fields)
+{
+	unsigned int i, j, n_dynamic_fields = 0;
+	struct synth_event *event;
+
+	event = kzalloc(sizeof(*event), GFP_KERNEL);
+	if (!event) {
+		event = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	event->name = kstrdup(name, GFP_KERNEL);
+	if (!event->name) {
+		kfree(event);
+		event = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
+	if (!event->fields) {
+		free_synth_event(event);
+		event = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	for (i = 0; i < n_fields; i++)
+		if (fields[i]->is_dynamic)
+			n_dynamic_fields++;
+
+	if (n_dynamic_fields) {
+		event->dynamic_fields = kcalloc(n_dynamic_fields,
+						sizeof(*event->dynamic_fields),
+						GFP_KERNEL);
+		if (!event->dynamic_fields) {
+			free_synth_event(event);
+			event = ERR_PTR(-ENOMEM);
+			goto out;
+		}
+	}
+
+	dyn_event_init(&event->devent, &synth_event_ops);
+
+	for (i = 0, j = 0; i < n_fields; i++) {
+		fields[i]->field_pos = i;
+		event->fields[i] = fields[i];
+
+		if (fields[i]->is_dynamic)
+			event->dynamic_fields[j++] = fields[i];
+	}
+	event->n_dynamic_fields = j;
+	event->n_fields = n_fields;
+ out:
+	return event;
+}
+
+static int synth_event_check_arg_fn(void *data)
+{
+	struct dynevent_arg_pair *arg_pair = data;
+	int size;
+
+	size = synth_field_size((char *)arg_pair->lhs);
+	if (size == 0) {
+		if (strstr((char *)arg_pair->lhs, "["))
+			return 0;
+	}
+
+	return size ? 0 : -EINVAL;
+}
+
+/**
+ * synth_event_add_field - Add a new field to a synthetic event cmd
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event
+ * @type: The type of the new field to add
+ * @name: The name of the new field to add
+ *
+ * Add a new field to a synthetic event cmd object.  Field ordering is in
+ * the same order the fields are added.
+ *
+ * See synth_field_size() for available types. If field_name contains
+ * [n] the field is considered to be an array.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
+			  const char *name)
+{
+	struct dynevent_arg_pair arg_pair;
+	int ret;
+
+	if (cmd->type != DYNEVENT_TYPE_SYNTH)
+		return -EINVAL;
+
+	if (!type || !name)
+		return -EINVAL;
+
+	dynevent_arg_pair_init(&arg_pair, 0, ';');
+
+	arg_pair.lhs = type;
+	arg_pair.rhs = name;
+
+	ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
+	if (ret)
+		return ret;
+
+	if (++cmd->n_fields > SYNTH_FIELDS_MAX)
+		ret = -EINVAL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(synth_event_add_field);
+
+/**
+ * synth_event_add_field_str - Add a new field to a synthetic event cmd
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event
+ * @type_name: The type and name of the new field to add, as a single string
+ *
+ * Add a new field to a synthetic event cmd object, as a single
+ * string.  The @type_name string is expected to be of the form 'type
+ * name', which will be appended by ';'.  No sanity checking is done -
+ * what's passed in is assumed to already be well-formed.  Field
+ * ordering is in the same order the fields are added.
+ *
+ * See synth_field_size() for available types. If field_name contains
+ * [n] the field is considered to be an array.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
+{
+	struct dynevent_arg arg;
+	int ret;
+
+	if (cmd->type != DYNEVENT_TYPE_SYNTH)
+		return -EINVAL;
+
+	if (!type_name)
+		return -EINVAL;
+
+	dynevent_arg_init(&arg, ';');
+
+	arg.str = type_name;
+
+	ret = dynevent_arg_add(cmd, &arg, NULL);
+	if (ret)
+		return ret;
+
+	if (++cmd->n_fields > SYNTH_FIELDS_MAX)
+		ret = -EINVAL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(synth_event_add_field_str);
+
+/**
+ * synth_event_add_fields - Add multiple fields to a synthetic event cmd
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event
+ * @fields: An array of type/name field descriptions
+ * @n_fields: The number of field descriptions contained in the fields array
+ *
+ * Add a new set of fields to a synthetic event cmd object.  The event
+ * fields that will be defined for the event should be passed in as an
+ * array of struct synth_field_desc, and the number of elements in the
+ * array passed in as n_fields.  Field ordering will retain the
+ * ordering given in the fields array.
+ *
+ * See synth_field_size() for available types. If field_name contains
+ * [n] the field is considered to be an array.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int synth_event_add_fields(struct dynevent_cmd *cmd,
+			   struct synth_field_desc *fields,
+			   unsigned int n_fields)
+{
+	unsigned int i;
+	int ret = 0;
+
+	for (i = 0; i < n_fields; i++) {
+		if (fields[i].type == NULL || fields[i].name == NULL) {
+			ret = -EINVAL;
+			break;
+		}
+
+		ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(synth_event_add_fields);
+
+/**
+ * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event
+ * @name: The name of the synthetic event
+ * @mod: The module creating the event, NULL if not created from a module
+ * @args: Variable number of arg (pairs), one pair for each field
+ *
+ * NOTE: Users normally won't want to call this function directly, but
+ * rather use the synth_event_gen_cmd_start() wrapper, which
+ * automatically adds a NULL to the end of the arg list.  If this
+ * function is used directly, make sure the last arg in the variable
+ * arg list is NULL.
+ *
+ * Generate a synthetic event command to be executed by
+ * synth_event_gen_cmd_end().  This function can be used to generate
+ * the complete command or only the first part of it; in the latter
+ * case, synth_event_add_field(), synth_event_add_field_str(), or
+ * synth_event_add_fields() can be used to add more fields following
+ * this.
+ *
+ * There should be an even number variable args, each pair consisting
+ * of a type followed by a field name.
+ *
+ * See synth_field_size() for available types. If field_name contains
+ * [n] the field is considered to be an array.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
+				struct module *mod, ...)
+{
+	struct dynevent_arg arg;
+	va_list args;
+	int ret;
+
+	cmd->event_name = name;
+	cmd->private_data = mod;
+
+	if (cmd->type != DYNEVENT_TYPE_SYNTH)
+		return -EINVAL;
+
+	dynevent_arg_init(&arg, 0);
+	arg.str = name;
+	ret = dynevent_arg_add(cmd, &arg, NULL);
+	if (ret)
+		return ret;
+
+	va_start(args, mod);
+	for (;;) {
+		const char *type, *name;
+
+		type = va_arg(args, const char *);
+		if (!type)
+			break;
+		name = va_arg(args, const char *);
+		if (!name)
+			break;
+
+		if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
+			ret = -EINVAL;
+			break;
+		}
+
+		ret = synth_event_add_field(cmd, type, name);
+		if (ret)
+			break;
+	}
+	va_end(args);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
+
+/**
+ * synth_event_gen_cmd_array_start - Start synthetic event command from an array
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event
+ * @name: The name of the synthetic event
+ * @fields: An array of type/name field descriptions
+ * @n_fields: The number of field descriptions contained in the fields array
+ *
+ * Generate a synthetic event command to be executed by
+ * synth_event_gen_cmd_end().  This function can be used to generate
+ * the complete command or only the first part of it; in the latter
+ * case, synth_event_add_field(), synth_event_add_field_str(), or
+ * synth_event_add_fields() can be used to add more fields following
+ * this.
+ *
+ * The event fields that will be defined for the event should be
+ * passed in as an array of struct synth_field_desc, and the number of
+ * elements in the array passed in as n_fields.  Field ordering will
+ * retain the ordering given in the fields array.
+ *
+ * See synth_field_size() for available types. If field_name contains
+ * [n] the field is considered to be an array.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
+				    struct module *mod,
+				    struct synth_field_desc *fields,
+				    unsigned int n_fields)
+{
+	struct dynevent_arg arg;
+	unsigned int i;
+	int ret = 0;
+
+	cmd->event_name = name;
+	cmd->private_data = mod;
+
+	if (cmd->type != DYNEVENT_TYPE_SYNTH)
+		return -EINVAL;
+
+	if (n_fields > SYNTH_FIELDS_MAX)
+		return -EINVAL;
+
+	dynevent_arg_init(&arg, 0);
+	arg.str = name;
+	ret = dynevent_arg_add(cmd, &arg, NULL);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < n_fields; i++) {
+		if (fields[i].type == NULL || fields[i].name == NULL)
+			return -EINVAL;
+
+		ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
+
+static int __create_synth_event(const char *name, const char *raw_fields)
+{
+	char **argv, *field_str, *tmp_fields, *saved_fields = NULL;
+	struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
+	int consumed, cmd_version = 1, n_fields_this_loop;
+	int i, argc, n_fields = 0, ret = 0;
+	struct synth_event *event = NULL;
+
+	/*
+	 * Argument syntax:
+	 *  - Add synthetic event: <event_name> field[;field] ...
+	 *  - Remove synthetic event: !<event_name> field[;field] ...
+	 *      where 'field' = type field_name
+	 */
+
+	if (name[0] == '\0') {
+		synth_err(SYNTH_ERR_INVALID_CMD, 0);
+		return -EINVAL;
+	}
+
+	if (!is_good_name(name)) {
+		synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
+		return -EINVAL;
+	}
+
+	mutex_lock(&event_mutex);
+
+	event = find_synth_event(name);
+	if (event) {
+		synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
+		ret = -EEXIST;
+		goto err;
+	}
+
+	tmp_fields = saved_fields = kstrdup(raw_fields, GFP_KERNEL);
+	if (!tmp_fields) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	while ((field_str = strsep(&tmp_fields, ";")) != NULL) {
+		argv = argv_split(GFP_KERNEL, field_str, &argc);
+		if (!argv) {
+			ret = -ENOMEM;
+			goto err;
+		}
+
+		if (!argc) {
+			argv_free(argv);
+			continue;
+		}
+
+		n_fields_this_loop = 0;
+		consumed = 0;
+		while (argc > consumed) {
+			int field_version;
+
+			field = parse_synth_field(argc - consumed,
+						  argv + consumed, &consumed,
+						  &field_version);
+			if (IS_ERR(field)) {
+				ret = PTR_ERR(field);
+				goto err_free_arg;
+			}
+
+			/*
+			 * Track the highest version of any field we
+			 * found in the command.
+			 */
+			if (field_version > cmd_version)
+				cmd_version = field_version;
+
+			/*
+			 * Now sort out what is and isn't valid for
+			 * each supported version.
+			 *
+			 * If we see more than 1 field per loop, it
+			 * means we have multiple fields between
+			 * semicolons, and that's something we no
+			 * longer support in a version 2 or greater
+			 * command.
+			 */
+			if (cmd_version > 1 && n_fields_this_loop >= 1) {
+				synth_err(SYNTH_ERR_INVALID_CMD, errpos(field_str));
+				ret = -EINVAL;
+				goto err_free_arg;
+			}
+
+			if (n_fields == SYNTH_FIELDS_MAX) {
+				synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
+				ret = -EINVAL;
+				goto err_free_arg;
+			}
+			fields[n_fields++] = field;
+
+			n_fields_this_loop++;
+		}
+		argv_free(argv);
+
+		if (consumed < argc) {
+			synth_err(SYNTH_ERR_INVALID_CMD, 0);
+			ret = -EINVAL;
+			goto err;
+		}
+
+	}
+
+	if (n_fields == 0) {
+		synth_err(SYNTH_ERR_INVALID_CMD, 0);
+		ret = -EINVAL;
+		goto err;
+	}
+
+	event = alloc_synth_event(name, n_fields, fields);
+	if (IS_ERR(event)) {
+		ret = PTR_ERR(event);
+		event = NULL;
+		goto err;
+	}
+	ret = register_synth_event(event);
+	if (!ret)
+		dyn_event_add(&event->devent, &event->call);
+	else
+		free_synth_event(event);
+ out:
+	mutex_unlock(&event_mutex);
+
+	kfree(saved_fields);
+
+	return ret;
+ err_free_arg:
+	argv_free(argv);
+ err:
+	for (i = 0; i < n_fields; i++)
+		free_synth_field(fields[i]);
+
+	goto out;
+}
+
+/**
+ * synth_event_create - Create a new synthetic event
+ * @name: The name of the new synthetic event
+ * @fields: An array of type/name field descriptions
+ * @n_fields: The number of field descriptions contained in the fields array
+ * @mod: The module creating the event, NULL if not created from a module
+ *
+ * Create a new synthetic event with the given name under the
+ * trace/events/synthetic/ directory.  The event fields that will be
+ * defined for the event should be passed in as an array of struct
+ * synth_field_desc, and the number elements in the array passed in as
+ * n_fields. Field ordering will retain the ordering given in the
+ * fields array.
+ *
+ * If the new synthetic event is being created from a module, the mod
+ * param must be non-NULL.  This will ensure that the trace buffer
+ * won't contain unreadable events.
+ *
+ * The new synth event should be deleted using synth_event_delete()
+ * function.  The new synthetic event can be generated from modules or
+ * other kernel code using trace_synth_event() and related functions.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int synth_event_create(const char *name, struct synth_field_desc *fields,
+		       unsigned int n_fields, struct module *mod)
+{
+	struct dynevent_cmd cmd;
+	char *buf;
+	int ret;
+
+	buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
+
+	ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
+					      fields, n_fields);
+	if (ret)
+		goto out;
+
+	ret = synth_event_gen_cmd_end(&cmd);
+ out:
+	kfree(buf);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(synth_event_create);
+
+static int destroy_synth_event(struct synth_event *se)
+{
+	int ret;
+
+	if (se->ref)
+		return -EBUSY;
+
+	if (trace_event_dyn_busy(&se->call))
+		return -EBUSY;
+
+	ret = unregister_synth_event(se);
+	if (!ret) {
+		dyn_event_remove(&se->devent);
+		free_synth_event(se);
+	}
+
+	return ret;
+}
+
+/**
+ * synth_event_delete - Delete a synthetic event
+ * @event_name: The name of the new synthetic event
+ *
+ * Delete a synthetic event that was created with synth_event_create().
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int synth_event_delete(const char *event_name)
+{
+	struct synth_event *se = NULL;
+	struct module *mod = NULL;
+	int ret = -ENOENT;
+
+	mutex_lock(&event_mutex);
+	se = find_synth_event(event_name);
+	if (se) {
+		mod = se->mod;
+		ret = destroy_synth_event(se);
+	}
+	mutex_unlock(&event_mutex);
+
+	if (mod) {
+		/*
+		 * It is safest to reset the ring buffer if the module
+		 * being unloaded registered any events that were
+		 * used. The only worry is if a new module gets
+		 * loaded, and takes on the same id as the events of
+		 * this module. When printing out the buffer, traced
+		 * events left over from this module may be passed to
+		 * the new module events and unexpected results may
+		 * occur.
+		 */
+		tracing_reset_all_online_cpus();
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(synth_event_delete);
+
+static int check_command(const char *raw_command)
+{
+	char **argv = NULL, *cmd, *saved_cmd, *name_and_field;
+	int argc, ret = 0;
+
+	cmd = saved_cmd = kstrdup(raw_command, GFP_KERNEL);
+	if (!cmd)
+		return -ENOMEM;
+
+	name_and_field = strsep(&cmd, ";");
+	if (!name_and_field) {
+		ret = -EINVAL;
+		goto free;
+	}
+
+	if (name_and_field[0] == '!')
+		goto free;
+
+	argv = argv_split(GFP_KERNEL, name_and_field, &argc);
+	if (!argv) {
+		ret = -ENOMEM;
+		goto free;
+	}
+	argv_free(argv);
+
+	if (argc < 3)
+		ret = -EINVAL;
+free:
+	kfree(saved_cmd);
+
+	return ret;
+}
+
+static int create_or_delete_synth_event(const char *raw_command)
+{
+	char *name = NULL, *fields, *p;
+	int ret = 0;
+
+	raw_command = skip_spaces(raw_command);
+	if (raw_command[0] == '\0')
+		return ret;
+
+	last_cmd_set(raw_command);
+
+	ret = check_command(raw_command);
+	if (ret) {
+		synth_err(SYNTH_ERR_INVALID_CMD, 0);
+		return ret;
+	}
+
+	p = strpbrk(raw_command, " \t");
+	if (!p && raw_command[0] != '!') {
+		synth_err(SYNTH_ERR_INVALID_CMD, 0);
+		ret = -EINVAL;
+		goto free;
+	}
+
+	name = kmemdup_nul(raw_command, p ? p - raw_command : strlen(raw_command), GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+
+	if (name[0] == '!') {
+		ret = synth_event_delete(name + 1);
+		goto free;
+	}
+
+	fields = skip_spaces(p);
+
+	ret = __create_synth_event(name, fields);
+free:
+	kfree(name);
+
+	return ret;
+}
+
+static int synth_event_run_command(struct dynevent_cmd *cmd)
+{
+	struct synth_event *se;
+	int ret;
+
+	ret = create_or_delete_synth_event(cmd->seq.buffer);
+	if (ret)
+		return ret;
+
+	se = find_synth_event(cmd->event_name);
+	if (WARN_ON(!se))
+		return -ENOENT;
+
+	se->mod = cmd->private_data;
+
+	return ret;
+}
+
+/**
+ * synth_event_cmd_init - Initialize a synthetic event command object
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event
+ * @buf: A pointer to the buffer used to build the command
+ * @maxlen: The length of the buffer passed in @buf
+ *
+ * Initialize a synthetic event command object.  Use this before
+ * calling any of the other dyenvent_cmd functions.
+ */
+void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
+{
+	dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
+			  synth_event_run_command);
+}
+EXPORT_SYMBOL_GPL(synth_event_cmd_init);
+
+static inline int
+__synth_event_trace_init(struct trace_event_file *file,
+			 struct synth_event_trace_state *trace_state)
+{
+	int ret = 0;
+
+	memset(trace_state, '\0', sizeof(*trace_state));
+
+	/*
+	 * Normal event tracing doesn't get called at all unless the
+	 * ENABLED bit is set (which attaches the probe thus allowing
+	 * this code to be called, etc).  Because this is called
+	 * directly by the user, we don't have that but we still need
+	 * to honor not logging when disabled.  For the iterated
+	 * trace case, we save the enabled state upon start and just
+	 * ignore the following data calls.
+	 */
+	if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
+	    trace_trigger_soft_disabled(file)) {
+		trace_state->disabled = true;
+		ret = -ENOENT;
+		goto out;
+	}
+
+	trace_state->event = file->event_call->data;
+out:
+	return ret;
+}
+
+static inline int
+__synth_event_trace_start(struct trace_event_file *file,
+			  struct synth_event_trace_state *trace_state,
+			  int dynamic_fields_size)
+{
+	int entry_size, fields_size = 0;
+	int ret = 0;
+
+	fields_size = trace_state->event->n_u64 * sizeof(u64);
+	fields_size += dynamic_fields_size;
+
+	/*
+	 * Avoid ring buffer recursion detection, as this event
+	 * is being performed within another event.
+	 */
+	trace_state->buffer = file->tr->array_buffer.buffer;
+	ring_buffer_nest_start(trace_state->buffer);
+
+	entry_size = sizeof(*trace_state->entry) + fields_size;
+	trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
+							file,
+							entry_size);
+	if (!trace_state->entry) {
+		ring_buffer_nest_end(trace_state->buffer);
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static inline void
+__synth_event_trace_end(struct synth_event_trace_state *trace_state)
+{
+	trace_event_buffer_commit(&trace_state->fbuffer);
+
+	ring_buffer_nest_end(trace_state->buffer);
+}
+
+/**
+ * synth_event_trace - Trace a synthetic event
+ * @file: The trace_event_file representing the synthetic event
+ * @n_vals: The number of values in vals
+ * @args: Variable number of args containing the event values
+ *
+ * Trace a synthetic event using the values passed in the variable
+ * argument list.
+ *
+ * The argument list should be a list 'n_vals' u64 values.  The number
+ * of vals must match the number of field in the synthetic event, and
+ * must be in the same order as the synthetic event fields.
+ *
+ * All vals should be cast to u64, and string vals are just pointers
+ * to strings, cast to u64.  Strings will be copied into space
+ * reserved in the event for the string, using these pointers.
+ *
+ * Return: 0 on success, err otherwise.
+ */
+int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
+{
+	unsigned int i, n_u64, len, data_size = 0;
+	struct synth_event_trace_state state;
+	va_list args;
+	int ret;
+
+	ret = __synth_event_trace_init(file, &state);
+	if (ret) {
+		if (ret == -ENOENT)
+			ret = 0; /* just disabled, not really an error */
+		return ret;
+	}
+
+	if (state.event->n_dynamic_fields) {
+		va_start(args, n_vals);
+
+		for (i = 0; i < state.event->n_fields; i++) {
+			u64 val = va_arg(args, u64);
+
+			if (state.event->fields[i]->is_string &&
+			    state.event->fields[i]->is_dynamic) {
+				char *str_val = (char *)(long)val;
+
+				data_size += strlen(str_val) + 1;
+			}
+		}
+
+		va_end(args);
+	}
+
+	ret = __synth_event_trace_start(file, &state, data_size);
+	if (ret)
+		return ret;
+
+	if (n_vals != state.event->n_fields) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	data_size = 0;
+
+	va_start(args, n_vals);
+	for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
+		u64 val;
+
+		val = va_arg(args, u64);
+
+		if (state.event->fields[i]->is_string) {
+			char *str_val = (char *)(long)val;
+
+			len = trace_string(state.entry, state.event, str_val,
+					   state.event->fields[i]->is_dynamic,
+					   data_size, &n_u64);
+			data_size += len; /* only dynamic string increments */
+		} else {
+			struct synth_field *field = state.event->fields[i];
+
+			switch (field->size) {
+			case 1:
+				*(u8 *)&state.entry->fields[n_u64] = (u8)val;
+				break;
+
+			case 2:
+				*(u16 *)&state.entry->fields[n_u64] = (u16)val;
+				break;
+
+			case 4:
+				*(u32 *)&state.entry->fields[n_u64] = (u32)val;
+				break;
+
+			default:
+				state.entry->fields[n_u64] = val;
+				break;
+			}
+			n_u64++;
+		}
+	}
+	va_end(args);
+out:
+	__synth_event_trace_end(&state);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(synth_event_trace);
+
+/**
+ * synth_event_trace_array - Trace a synthetic event from an array
+ * @file: The trace_event_file representing the synthetic event
+ * @vals: Array of values
+ * @n_vals: The number of values in vals
+ *
+ * Trace a synthetic event using the values passed in as 'vals'.
+ *
+ * The 'vals' array is just an array of 'n_vals' u64.  The number of
+ * vals must match the number of field in the synthetic event, and
+ * must be in the same order as the synthetic event fields.
+ *
+ * All vals should be cast to u64, and string vals are just pointers
+ * to strings, cast to u64.  Strings will be copied into space
+ * reserved in the event for the string, using these pointers.
+ *
+ * Return: 0 on success, err otherwise.
+ */
+int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
+			    unsigned int n_vals)
+{
+	unsigned int i, n_u64, field_pos, len, data_size = 0;
+	struct synth_event_trace_state state;
+	char *str_val;
+	int ret;
+
+	ret = __synth_event_trace_init(file, &state);
+	if (ret) {
+		if (ret == -ENOENT)
+			ret = 0; /* just disabled, not really an error */
+		return ret;
+	}
+
+	if (state.event->n_dynamic_fields) {
+		for (i = 0; i < state.event->n_dynamic_fields; i++) {
+			field_pos = state.event->dynamic_fields[i]->field_pos;
+			str_val = (char *)(long)vals[field_pos];
+			len = strlen(str_val) + 1;
+			data_size += len;
+		}
+	}
+
+	ret = __synth_event_trace_start(file, &state, data_size);
+	if (ret)
+		return ret;
+
+	if (n_vals != state.event->n_fields) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	data_size = 0;
+
+	for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
+		if (state.event->fields[i]->is_string) {
+			char *str_val = (char *)(long)vals[i];
+
+			len = trace_string(state.entry, state.event, str_val,
+					   state.event->fields[i]->is_dynamic,
+					   data_size, &n_u64);
+			data_size += len; /* only dynamic string increments */
+		} else {
+			struct synth_field *field = state.event->fields[i];
+			u64 val = vals[i];
+
+			switch (field->size) {
+			case 1:
+				*(u8 *)&state.entry->fields[n_u64] = (u8)val;
+				break;
+
+			case 2:
+				*(u16 *)&state.entry->fields[n_u64] = (u16)val;
+				break;
+
+			case 4:
+				*(u32 *)&state.entry->fields[n_u64] = (u32)val;
+				break;
+
+			default:
+				state.entry->fields[n_u64] = val;
+				break;
+			}
+			n_u64++;
+		}
+	}
+out:
+	__synth_event_trace_end(&state);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(synth_event_trace_array);
+
+/**
+ * synth_event_trace_start - Start piecewise synthetic event trace
+ * @file: The trace_event_file representing the synthetic event
+ * @trace_state: A pointer to object tracking the piecewise trace state
+ *
+ * Start the trace of a synthetic event field-by-field rather than all
+ * at once.
+ *
+ * This function 'opens' an event trace, which means space is reserved
+ * for the event in the trace buffer, after which the event's
+ * individual field values can be set through either
+ * synth_event_add_next_val() or synth_event_add_val().
+ *
+ * A pointer to a trace_state object is passed in, which will keep
+ * track of the current event trace state until the event trace is
+ * closed (and the event finally traced) using
+ * synth_event_trace_end().
+ *
+ * Note that synth_event_trace_end() must be called after all values
+ * have been added for each event trace, regardless of whether adding
+ * all field values succeeded or not.
+ *
+ * Note also that for a given event trace, all fields must be added
+ * using either synth_event_add_next_val() or synth_event_add_val()
+ * but not both together or interleaved.
+ *
+ * Return: 0 on success, err otherwise.
+ */
+int synth_event_trace_start(struct trace_event_file *file,
+			    struct synth_event_trace_state *trace_state)
+{
+	int ret;
+
+	if (!trace_state)
+		return -EINVAL;
+
+	ret = __synth_event_trace_init(file, trace_state);
+	if (ret) {
+		if (ret == -ENOENT)
+			ret = 0; /* just disabled, not really an error */
+		return ret;
+	}
+
+	if (trace_state->event->n_dynamic_fields)
+		return -ENOTSUPP;
+
+	ret = __synth_event_trace_start(file, trace_state, 0);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(synth_event_trace_start);
+
+static int __synth_event_add_val(const char *field_name, u64 val,
+				 struct synth_event_trace_state *trace_state)
+{
+	struct synth_field *field = NULL;
+	struct synth_trace_event *entry;
+	struct synth_event *event;
+	int i, ret = 0;
+
+	if (!trace_state) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* can't mix add_next_synth_val() with add_synth_val() */
+	if (field_name) {
+		if (trace_state->add_next) {
+			ret = -EINVAL;
+			goto out;
+		}
+		trace_state->add_name = true;
+	} else {
+		if (trace_state->add_name) {
+			ret = -EINVAL;
+			goto out;
+		}
+		trace_state->add_next = true;
+	}
+
+	if (trace_state->disabled)
+		goto out;
+
+	event = trace_state->event;
+	if (trace_state->add_name) {
+		for (i = 0; i < event->n_fields; i++) {
+			field = event->fields[i];
+			if (strcmp(field->name, field_name) == 0)
+				break;
+		}
+		if (!field) {
+			ret = -EINVAL;
+			goto out;
+		}
+	} else {
+		if (trace_state->cur_field >= event->n_fields) {
+			ret = -EINVAL;
+			goto out;
+		}
+		field = event->fields[trace_state->cur_field++];
+	}
+
+	entry = trace_state->entry;
+	if (field->is_string) {
+		char *str_val = (char *)(long)val;
+		char *str_field;
+
+		if (field->is_dynamic) { /* add_val can't do dynamic strings */
+			ret = -EINVAL;
+			goto out;
+		}
+
+		if (!str_val) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		str_field = (char *)&entry->fields[field->offset];
+		strscpy(str_field, str_val, STR_VAR_LEN_MAX);
+	} else {
+		switch (field->size) {
+		case 1:
+			*(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
+			break;
+
+		case 2:
+			*(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
+			break;
+
+		case 4:
+			*(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
+			break;
+
+		default:
+			trace_state->entry->fields[field->offset] = val;
+			break;
+		}
+	}
+ out:
+	return ret;
+}
+
+/**
+ * synth_event_add_next_val - Add the next field's value to an open synth trace
+ * @val: The value to set the next field to
+ * @trace_state: A pointer to object tracking the piecewise trace state
+ *
+ * Set the value of the next field in an event that's been opened by
+ * synth_event_trace_start().
+ *
+ * The val param should be the value cast to u64.  If the value points
+ * to a string, the val param should be a char * cast to u64.
+ *
+ * This function assumes all the fields in an event are to be set one
+ * after another - successive calls to this function are made, one for
+ * each field, in the order of the fields in the event, until all
+ * fields have been set.  If you'd rather set each field individually
+ * without regard to ordering, synth_event_add_val() can be used
+ * instead.
+ *
+ * Note however that synth_event_add_next_val() and
+ * synth_event_add_val() can't be intermixed for a given event trace -
+ * one or the other but not both can be used at the same time.
+ *
+ * Note also that synth_event_trace_end() must be called after all
+ * values have been added for each event trace, regardless of whether
+ * adding all field values succeeded or not.
+ *
+ * Return: 0 on success, err otherwise.
+ */
+int synth_event_add_next_val(u64 val,
+			     struct synth_event_trace_state *trace_state)
+{
+	return __synth_event_add_val(NULL, val, trace_state);
+}
+EXPORT_SYMBOL_GPL(synth_event_add_next_val);
+
+/**
+ * synth_event_add_val - Add a named field's value to an open synth trace
+ * @field_name: The name of the synthetic event field value to set
+ * @val: The value to set the named field to
+ * @trace_state: A pointer to object tracking the piecewise trace state
+ *
+ * Set the value of the named field in an event that's been opened by
+ * synth_event_trace_start().
+ *
+ * The val param should be the value cast to u64.  If the value points
+ * to a string, the val param should be a char * cast to u64.
+ *
+ * This function looks up the field name, and if found, sets the field
+ * to the specified value.  This lookup makes this function more
+ * expensive than synth_event_add_next_val(), so use that or the
+ * none-piecewise synth_event_trace() instead if efficiency is more
+ * important.
+ *
+ * Note however that synth_event_add_next_val() and
+ * synth_event_add_val() can't be intermixed for a given event trace -
+ * one or the other but not both can be used at the same time.
+ *
+ * Note also that synth_event_trace_end() must be called after all
+ * values have been added for each event trace, regardless of whether
+ * adding all field values succeeded or not.
+ *
+ * Return: 0 on success, err otherwise.
+ */
+int synth_event_add_val(const char *field_name, u64 val,
+			struct synth_event_trace_state *trace_state)
+{
+	return __synth_event_add_val(field_name, val, trace_state);
+}
+EXPORT_SYMBOL_GPL(synth_event_add_val);
+
+/**
+ * synth_event_trace_end - End piecewise synthetic event trace
+ * @trace_state: A pointer to object tracking the piecewise trace state
+ *
+ * End the trace of a synthetic event opened by
+ * synth_event_trace__start().
+ *
+ * This function 'closes' an event trace, which basically means that
+ * it commits the reserved event and cleans up other loose ends.
+ *
+ * A pointer to a trace_state object is passed in, which will keep
+ * track of the current event trace state opened with
+ * synth_event_trace_start().
+ *
+ * Note that this function must be called after all values have been
+ * added for each event trace, regardless of whether adding all field
+ * values succeeded or not.
+ *
+ * Return: 0 on success, err otherwise.
+ */
+int synth_event_trace_end(struct synth_event_trace_state *trace_state)
+{
+	if (!trace_state)
+		return -EINVAL;
+
+	__synth_event_trace_end(trace_state);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(synth_event_trace_end);
+
+static int create_synth_event(const char *raw_command)
+{
+	char *fields, *p;
+	const char *name;
+	int len, ret = 0;
+
+	raw_command = skip_spaces(raw_command);
+	if (raw_command[0] == '\0')
+		return ret;
+
+	last_cmd_set(raw_command);
+
+	name = raw_command;
+
+	/* Don't try to process if not our system */
+	if (name[0] != 's' || name[1] != ':')
+		return -ECANCELED;
+	name += 2;
+
+	p = strpbrk(raw_command, " \t");
+	if (!p) {
+		synth_err(SYNTH_ERR_INVALID_CMD, 0);
+		return -EINVAL;
+	}
+
+	fields = skip_spaces(p);
+
+	/* This interface accepts group name prefix */
+	if (strchr(name, '/')) {
+		len = str_has_prefix(name, SYNTH_SYSTEM "/");
+		if (len == 0) {
+			synth_err(SYNTH_ERR_INVALID_DYN_CMD, 0);
+			return -EINVAL;
+		}
+		name += len;
+	}
+
+	len = name - raw_command;
+
+	ret = check_command(raw_command + len);
+	if (ret) {
+		synth_err(SYNTH_ERR_INVALID_CMD, 0);
+		return ret;
+	}
+
+	name = kmemdup_nul(raw_command + len, p - raw_command - len, GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+
+	ret = __create_synth_event(name, fields);
+
+	kfree(name);
+
+	return ret;
+}
+
+static int synth_event_release(struct dyn_event *ev)
+{
+	struct synth_event *event = to_synth_event(ev);
+	int ret;
+
+	if (event->ref)
+		return -EBUSY;
+
+	if (trace_event_dyn_busy(&event->call))
+		return -EBUSY;
+
+	ret = unregister_synth_event(event);
+	if (ret)
+		return ret;
+
+	dyn_event_remove(ev);
+	free_synth_event(event);
+	return 0;
+}
+
+static int __synth_event_show(struct seq_file *m, struct synth_event *event)
+{
+	struct synth_field *field;
+	unsigned int i;
+	char *type, *t;
+
+	seq_printf(m, "%s\t", event->name);
+
+	for (i = 0; i < event->n_fields; i++) {
+		field = event->fields[i];
+
+		type = field->type;
+		t = strstr(type, "__data_loc");
+		if (t) { /* __data_loc belongs in format but not event desc */
+			t += sizeof("__data_loc");
+			type = t;
+		}
+
+		/* parameter values */
+		seq_printf(m, "%s %s%s", type, field->name,
+			   i == event->n_fields - 1 ? "" : "; ");
+	}
+
+	seq_putc(m, '\n');
+
+	return 0;
+}
+
+static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
+{
+	struct synth_event *event = to_synth_event(ev);
+
+	seq_printf(m, "s:%s/", event->class.system);
+
+	return __synth_event_show(m, event);
+}
+
+static int synth_events_seq_show(struct seq_file *m, void *v)
+{
+	struct dyn_event *ev = v;
+
+	if (!is_synth_event(ev))
+		return 0;
+
+	return __synth_event_show(m, to_synth_event(ev));
+}
+
+static const struct seq_operations synth_events_seq_op = {
+	.start	= dyn_event_seq_start,
+	.next	= dyn_event_seq_next,
+	.stop	= dyn_event_seq_stop,
+	.show	= synth_events_seq_show,
+};
+
+static int synth_events_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+		ret = dyn_events_release_all(&synth_event_ops);
+		if (ret < 0)
+			return ret;
+	}
+
+	return seq_open(file, &synth_events_seq_op);
+}
+
+static ssize_t synth_events_write(struct file *file,
+				  const char __user *buffer,
+				  size_t count, loff_t *ppos)
+{
+	return trace_parse_run_command(file, buffer, count, ppos,
+				       create_or_delete_synth_event);
+}
+
+static const struct file_operations synth_events_fops = {
+	.open           = synth_events_open,
+	.write		= synth_events_write,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release        = seq_release,
+};
+
+/*
+ * Register dynevent at core_initcall. This allows kernel to setup kprobe
+ * events in postcore_initcall without tracefs.
+ */
+static __init int trace_events_synth_init_early(void)
+{
+	int err = 0;
+
+	err = dyn_event_register(&synth_event_ops);
+	if (err)
+		pr_warn("Could not register synth_event_ops\n");
+
+	return err;
+}
+core_initcall(trace_events_synth_init_early);
+
+static __init int trace_events_synth_init(void)
+{
+	struct dentry *entry = NULL;
+	int err = 0;
+	err = tracing_init_dentry();
+	if (err)
+		goto err;
+
+	entry = tracefs_create_file("synthetic_events", TRACE_MODE_WRITE,
+				    NULL, NULL, &synth_events_fops);
+	if (!entry) {
+		err = -ENODEV;
+		goto err;
+	}
+
+	return err;
+ err:
+	pr_warn("Could not create tracefs 'synthetic_events' entry\n");
+
+	return err;
+}
+
+fs_initcall(trace_events_synth_init);
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
new file mode 100644
index 000000000..918730d74
--- /dev/null
+++ b/kernel/trace/trace_events_trigger.c
@@ -0,0 +1,1982 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_events_trigger - trace event triggers
+ *
+ * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
+ */
+
+#include <linux/security.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/rculist.h>
+
+#include "trace.h"
+
+static LIST_HEAD(trigger_commands);
+static DEFINE_MUTEX(trigger_cmd_mutex);
+
+void trigger_data_free(struct event_trigger_data *data)
+{
+	if (data->cmd_ops->set_filter)
+		data->cmd_ops->set_filter(NULL, data, NULL);
+
+	/* make sure current triggers exit before free */
+	tracepoint_synchronize_unregister();
+
+	kfree(data);
+}
+
+/**
+ * event_triggers_call - Call triggers associated with a trace event
+ * @file: The trace_event_file associated with the event
+ * @rec: The trace entry for the event, NULL for unconditional invocation
+ *
+ * For each trigger associated with an event, invoke the trigger
+ * function registered with the associated trigger command.  If rec is
+ * non-NULL, it means that the trigger requires further processing and
+ * shouldn't be unconditionally invoked.  If rec is non-NULL and the
+ * trigger has a filter associated with it, rec will checked against
+ * the filter and if the record matches the trigger will be invoked.
+ * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
+ * in any case until the current event is written, the trigger
+ * function isn't invoked but the bit associated with the deferred
+ * trigger is set in the return value.
+ *
+ * Returns an enum event_trigger_type value containing a set bit for
+ * any trigger that should be deferred, ETT_NONE if nothing to defer.
+ *
+ * Called from tracepoint handlers (with rcu_read_lock_sched() held).
+ *
+ * Return: an enum event_trigger_type value containing a set bit for
+ * any trigger that should be deferred, ETT_NONE if nothing to defer.
+ */
+enum event_trigger_type
+event_triggers_call(struct trace_event_file *file,
+		    struct trace_buffer *buffer, void *rec,
+		    struct ring_buffer_event *event)
+{
+	struct event_trigger_data *data;
+	enum event_trigger_type tt = ETT_NONE;
+	struct event_filter *filter;
+
+	if (list_empty(&file->triggers))
+		return tt;
+
+	list_for_each_entry_rcu(data, &file->triggers, list) {
+		if (data->paused)
+			continue;
+		if (!rec) {
+			data->ops->trigger(data, buffer, rec, event);
+			continue;
+		}
+		filter = rcu_dereference_sched(data->filter);
+		if (filter && !filter_match_preds(filter, rec))
+			continue;
+		if (event_command_post_trigger(data->cmd_ops)) {
+			tt |= data->cmd_ops->trigger_type;
+			continue;
+		}
+		data->ops->trigger(data, buffer, rec, event);
+	}
+	return tt;
+}
+EXPORT_SYMBOL_GPL(event_triggers_call);
+
+bool __trace_trigger_soft_disabled(struct trace_event_file *file)
+{
+	unsigned long eflags = file->flags;
+
+	if (eflags & EVENT_FILE_FL_TRIGGER_MODE)
+		event_triggers_call(file, NULL, NULL, NULL);
+	if (eflags & EVENT_FILE_FL_SOFT_DISABLED)
+		return true;
+	if (eflags & EVENT_FILE_FL_PID_FILTER)
+		return trace_event_ignore_this_pid(file);
+	return false;
+}
+EXPORT_SYMBOL_GPL(__trace_trigger_soft_disabled);
+
+/**
+ * event_triggers_post_call - Call 'post_triggers' for a trace event
+ * @file: The trace_event_file associated with the event
+ * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
+ *
+ * For each trigger associated with an event, invoke the trigger
+ * function registered with the associated trigger command, if the
+ * corresponding bit is set in the tt enum passed into this function.
+ * See @event_triggers_call for details on how those bits are set.
+ *
+ * Called from tracepoint handlers (with rcu_read_lock_sched() held).
+ */
+void
+event_triggers_post_call(struct trace_event_file *file,
+			 enum event_trigger_type tt)
+{
+	struct event_trigger_data *data;
+
+	list_for_each_entry_rcu(data, &file->triggers, list) {
+		if (data->paused)
+			continue;
+		if (data->cmd_ops->trigger_type & tt)
+			data->ops->trigger(data, NULL, NULL, NULL);
+	}
+}
+EXPORT_SYMBOL_GPL(event_triggers_post_call);
+
+#define SHOW_AVAILABLE_TRIGGERS	(void *)(1UL)
+
+static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
+{
+	struct trace_event_file *event_file = event_file_data(m->private);
+
+	if (t == SHOW_AVAILABLE_TRIGGERS) {
+		(*pos)++;
+		return NULL;
+	}
+	return seq_list_next(t, &event_file->triggers, pos);
+}
+
+static bool check_user_trigger(struct trace_event_file *file)
+{
+	struct event_trigger_data *data;
+
+	list_for_each_entry_rcu(data, &file->triggers, list,
+				lockdep_is_held(&event_mutex)) {
+		if (data->flags & EVENT_TRIGGER_FL_PROBE)
+			continue;
+		return true;
+	}
+	return false;
+}
+
+static void *trigger_start(struct seq_file *m, loff_t *pos)
+{
+	struct trace_event_file *event_file;
+
+	/* ->stop() is called even if ->start() fails */
+	mutex_lock(&event_mutex);
+	event_file = event_file_data(m->private);
+	if (unlikely(!event_file))
+		return ERR_PTR(-ENODEV);
+
+	if (list_empty(&event_file->triggers) || !check_user_trigger(event_file))
+		return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
+
+	return seq_list_start(&event_file->triggers, *pos);
+}
+
+static void trigger_stop(struct seq_file *m, void *t)
+{
+	mutex_unlock(&event_mutex);
+}
+
+static int trigger_show(struct seq_file *m, void *v)
+{
+	struct event_trigger_data *data;
+	struct event_command *p;
+
+	if (v == SHOW_AVAILABLE_TRIGGERS) {
+		seq_puts(m, "# Available triggers:\n");
+		seq_putc(m, '#');
+		mutex_lock(&trigger_cmd_mutex);
+		list_for_each_entry_reverse(p, &trigger_commands, list)
+			seq_printf(m, " %s", p->name);
+		seq_putc(m, '\n');
+		mutex_unlock(&trigger_cmd_mutex);
+		return 0;
+	}
+
+	data = list_entry(v, struct event_trigger_data, list);
+	data->ops->print(m, data);
+
+	return 0;
+}
+
+static const struct seq_operations event_triggers_seq_ops = {
+	.start = trigger_start,
+	.next = trigger_next,
+	.stop = trigger_stop,
+	.show = trigger_show,
+};
+
+static int event_trigger_regex_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	mutex_lock(&event_mutex);
+
+	if (unlikely(!event_file_data(file))) {
+		mutex_unlock(&event_mutex);
+		return -ENODEV;
+	}
+
+	if ((file->f_mode & FMODE_WRITE) &&
+	    (file->f_flags & O_TRUNC)) {
+		struct trace_event_file *event_file;
+		struct event_command *p;
+
+		event_file = event_file_data(file);
+
+		list_for_each_entry(p, &trigger_commands, list) {
+			if (p->unreg_all)
+				p->unreg_all(event_file);
+		}
+	}
+
+	if (file->f_mode & FMODE_READ) {
+		ret = seq_open(file, &event_triggers_seq_ops);
+		if (!ret) {
+			struct seq_file *m = file->private_data;
+			m->private = file;
+		}
+	}
+
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+int trigger_process_regex(struct trace_event_file *file, char *buff)
+{
+	char *command, *next;
+	struct event_command *p;
+	int ret = -EINVAL;
+
+	next = buff = skip_spaces(buff);
+	command = strsep(&next, ": \t");
+	if (next) {
+		next = skip_spaces(next);
+		if (!*next)
+			next = NULL;
+	}
+	command = (command[0] != '!') ? command : command + 1;
+
+	mutex_lock(&trigger_cmd_mutex);
+	list_for_each_entry(p, &trigger_commands, list) {
+		if (strcmp(p->name, command) == 0) {
+			ret = p->parse(p, file, buff, command, next);
+			goto out_unlock;
+		}
+	}
+ out_unlock:
+	mutex_unlock(&trigger_cmd_mutex);
+
+	return ret;
+}
+
+static ssize_t event_trigger_regex_write(struct file *file,
+					 const char __user *ubuf,
+					 size_t cnt, loff_t *ppos)
+{
+	struct trace_event_file *event_file;
+	ssize_t ret;
+	char *buf;
+
+	if (!cnt)
+		return 0;
+
+	if (cnt >= PAGE_SIZE)
+		return -EINVAL;
+
+	buf = memdup_user_nul(ubuf, cnt);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	strim(buf);
+
+	mutex_lock(&event_mutex);
+	event_file = event_file_data(file);
+	if (unlikely(!event_file)) {
+		mutex_unlock(&event_mutex);
+		kfree(buf);
+		return -ENODEV;
+	}
+	ret = trigger_process_regex(event_file, buf);
+	mutex_unlock(&event_mutex);
+
+	kfree(buf);
+	if (ret < 0)
+		goto out;
+
+	*ppos += cnt;
+	ret = cnt;
+ out:
+	return ret;
+}
+
+static int event_trigger_regex_release(struct inode *inode, struct file *file)
+{
+	mutex_lock(&event_mutex);
+
+	if (file->f_mode & FMODE_READ)
+		seq_release(inode, file);
+
+	mutex_unlock(&event_mutex);
+
+	return 0;
+}
+
+static ssize_t
+event_trigger_write(struct file *filp, const char __user *ubuf,
+		    size_t cnt, loff_t *ppos)
+{
+	return event_trigger_regex_write(filp, ubuf, cnt, ppos);
+}
+
+static int
+event_trigger_open(struct inode *inode, struct file *filp)
+{
+	/* Checks for tracefs lockdown */
+	return event_trigger_regex_open(inode, filp);
+}
+
+static int
+event_trigger_release(struct inode *inode, struct file *file)
+{
+	return event_trigger_regex_release(inode, file);
+}
+
+const struct file_operations event_trigger_fops = {
+	.open = event_trigger_open,
+	.read = seq_read,
+	.write = event_trigger_write,
+	.llseek = tracing_lseek,
+	.release = event_trigger_release,
+};
+
+/*
+ * Currently we only register event commands from __init, so mark this
+ * __init too.
+ */
+__init int register_event_command(struct event_command *cmd)
+{
+	struct event_command *p;
+	int ret = 0;
+
+	mutex_lock(&trigger_cmd_mutex);
+	list_for_each_entry(p, &trigger_commands, list) {
+		if (strcmp(cmd->name, p->name) == 0) {
+			ret = -EBUSY;
+			goto out_unlock;
+		}
+	}
+	list_add(&cmd->list, &trigger_commands);
+ out_unlock:
+	mutex_unlock(&trigger_cmd_mutex);
+
+	return ret;
+}
+
+/*
+ * Currently we only unregister event commands from __init, so mark
+ * this __init too.
+ */
+__init int unregister_event_command(struct event_command *cmd)
+{
+	struct event_command *p, *n;
+	int ret = -ENODEV;
+
+	mutex_lock(&trigger_cmd_mutex);
+	list_for_each_entry_safe(p, n, &trigger_commands, list) {
+		if (strcmp(cmd->name, p->name) == 0) {
+			ret = 0;
+			list_del_init(&p->list);
+			goto out_unlock;
+		}
+	}
+ out_unlock:
+	mutex_unlock(&trigger_cmd_mutex);
+
+	return ret;
+}
+
+/**
+ * event_trigger_print - Generic event_trigger_ops @print implementation
+ * @name: The name of the event trigger
+ * @m: The seq_file being printed to
+ * @data: Trigger-specific data
+ * @filter_str: filter_str to print, if present
+ *
+ * Common implementation for event triggers to print themselves.
+ *
+ * Usually wrapped by a function that simply sets the @name of the
+ * trigger command and then invokes this.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+static int
+event_trigger_print(const char *name, struct seq_file *m,
+		    void *data, char *filter_str)
+{
+	long count = (long)data;
+
+	seq_puts(m, name);
+
+	if (count == -1)
+		seq_puts(m, ":unlimited");
+	else
+		seq_printf(m, ":count=%ld", count);
+
+	if (filter_str)
+		seq_printf(m, " if %s\n", filter_str);
+	else
+		seq_putc(m, '\n');
+
+	return 0;
+}
+
+/**
+ * event_trigger_init - Generic event_trigger_ops @init implementation
+ * @data: Trigger-specific data
+ *
+ * Common implementation of event trigger initialization.
+ *
+ * Usually used directly as the @init method in event trigger
+ * implementations.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_init(struct event_trigger_data *data)
+{
+	data->ref++;
+	return 0;
+}
+
+/**
+ * event_trigger_free - Generic event_trigger_ops @free implementation
+ * @data: Trigger-specific data
+ *
+ * Common implementation of event trigger de-initialization.
+ *
+ * Usually used directly as the @free method in event trigger
+ * implementations.
+ */
+static void
+event_trigger_free(struct event_trigger_data *data)
+{
+	if (WARN_ON_ONCE(data->ref <= 0))
+		return;
+
+	data->ref--;
+	if (!data->ref)
+		trigger_data_free(data);
+}
+
+int trace_event_trigger_enable_disable(struct trace_event_file *file,
+				       int trigger_enable)
+{
+	int ret = 0;
+
+	if (trigger_enable) {
+		if (atomic_inc_return(&file->tm_ref) > 1)
+			return ret;
+		set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
+		ret = trace_event_enable_disable(file, 1, 1);
+	} else {
+		if (atomic_dec_return(&file->tm_ref) > 0)
+			return ret;
+		clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
+		ret = trace_event_enable_disable(file, 0, 1);
+	}
+
+	return ret;
+}
+
+/**
+ * clear_event_triggers - Clear all triggers associated with a trace array
+ * @tr: The trace array to clear
+ *
+ * For each trigger, the triggering event has its tm_ref decremented
+ * via trace_event_trigger_enable_disable(), and any associated event
+ * (in the case of enable/disable_event triggers) will have its sm_ref
+ * decremented via free()->trace_event_enable_disable().  That
+ * combination effectively reverses the soft-mode/trigger state added
+ * by trigger registration.
+ *
+ * Must be called with event_mutex held.
+ */
+void
+clear_event_triggers(struct trace_array *tr)
+{
+	struct trace_event_file *file;
+
+	list_for_each_entry(file, &tr->events, list) {
+		struct event_trigger_data *data, *n;
+		list_for_each_entry_safe(data, n, &file->triggers, list) {
+			trace_event_trigger_enable_disable(file, 0);
+			list_del_rcu(&data->list);
+			if (data->ops->free)
+				data->ops->free(data);
+		}
+	}
+}
+
+/**
+ * update_cond_flag - Set or reset the TRIGGER_COND bit
+ * @file: The trace_event_file associated with the event
+ *
+ * If an event has triggers and any of those triggers has a filter or
+ * a post_trigger, trigger invocation needs to be deferred until after
+ * the current event has logged its data, and the event should have
+ * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
+ * cleared.
+ */
+void update_cond_flag(struct trace_event_file *file)
+{
+	struct event_trigger_data *data;
+	bool set_cond = false;
+
+	lockdep_assert_held(&event_mutex);
+
+	list_for_each_entry(data, &file->triggers, list) {
+		if (data->filter || event_command_post_trigger(data->cmd_ops) ||
+		    event_command_needs_rec(data->cmd_ops)) {
+			set_cond = true;
+			break;
+		}
+	}
+
+	if (set_cond)
+		set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
+	else
+		clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
+}
+
+/**
+ * register_trigger - Generic event_command @reg implementation
+ * @glob: The raw string used to register the trigger
+ * @data: Trigger-specific data to associate with the trigger
+ * @file: The trace_event_file associated with the event
+ *
+ * Common implementation for event trigger registration.
+ *
+ * Usually used directly as the @reg method in event command
+ * implementations.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+static int register_trigger(char *glob,
+			    struct event_trigger_data *data,
+			    struct trace_event_file *file)
+{
+	struct event_trigger_data *test;
+	int ret = 0;
+
+	lockdep_assert_held(&event_mutex);
+
+	list_for_each_entry(test, &file->triggers, list) {
+		if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
+			ret = -EEXIST;
+			goto out;
+		}
+	}
+
+	if (data->ops->init) {
+		ret = data->ops->init(data);
+		if (ret < 0)
+			goto out;
+	}
+
+	list_add_rcu(&data->list, &file->triggers);
+
+	update_cond_flag(file);
+	ret = trace_event_trigger_enable_disable(file, 1);
+	if (ret < 0) {
+		list_del_rcu(&data->list);
+		update_cond_flag(file);
+	}
+out:
+	return ret;
+}
+
+/**
+ * unregister_trigger - Generic event_command @unreg implementation
+ * @glob: The raw string used to register the trigger
+ * @test: Trigger-specific data used to find the trigger to remove
+ * @file: The trace_event_file associated with the event
+ *
+ * Common implementation for event trigger unregistration.
+ *
+ * Usually used directly as the @unreg method in event command
+ * implementations.
+ */
+static void unregister_trigger(char *glob,
+			       struct event_trigger_data *test,
+			       struct trace_event_file *file)
+{
+	struct event_trigger_data *data = NULL, *iter;
+
+	lockdep_assert_held(&event_mutex);
+
+	list_for_each_entry(iter, &file->triggers, list) {
+		if (iter->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
+			data = iter;
+			list_del_rcu(&data->list);
+			trace_event_trigger_enable_disable(file, 0);
+			update_cond_flag(file);
+			break;
+		}
+	}
+
+	if (data && data->ops->free)
+		data->ops->free(data);
+}
+
+/*
+ * Event trigger parsing helper functions.
+ *
+ * These functions help make it easier to write an event trigger
+ * parsing function i.e. the struct event_command.parse() callback
+ * function responsible for parsing and registering a trigger command
+ * written to the 'trigger' file.
+ *
+ * A trigger command (or just 'trigger' for short) takes the form:
+ *   [trigger] [if filter]
+ *
+ * The struct event_command.parse() callback (and other struct
+ * event_command functions) refer to several components of a trigger
+ * command.  Those same components are referenced by the event trigger
+ * parsing helper functions defined below.  These components are:
+ *
+ *   cmd               - the trigger command name
+ *   glob              - the trigger command name optionally prefaced with '!'
+ *   param_and_filter  - text following cmd and ':'
+ *   param             - text following cmd and ':' and stripped of filter
+ *   filter            - the optional filter text following (and including) 'if'
+ *
+ * To illustrate the use of these componenents, here are some concrete
+ * examples. For the following triggers:
+ *
+ *   echo 'traceon:5 if pid == 0' > trigger
+ *     - 'traceon' is both cmd and glob
+ *     - '5 if pid == 0' is the param_and_filter
+ *     - '5' is the param
+ *     - 'if pid == 0' is the filter
+ *
+ *   echo 'enable_event:sys:event:n' > trigger
+ *     - 'enable_event' is both cmd and glob
+ *     - 'sys:event:n' is the param_and_filter
+ *     - 'sys:event:n' is the param
+ *     - there is no filter
+ *
+ *   echo 'hist:keys=pid if prio > 50' > trigger
+ *     - 'hist' is both cmd and glob
+ *     - 'keys=pid if prio > 50' is the param_and_filter
+ *     - 'keys=pid' is the param
+ *     - 'if prio > 50' is the filter
+ *
+ *   echo '!enable_event:sys:event:n' > trigger
+ *     - 'enable_event' the cmd
+ *     - '!enable_event' is the glob
+ *     - 'sys:event:n' is the param_and_filter
+ *     - 'sys:event:n' is the param
+ *     - there is no filter
+ *
+ *   echo 'traceoff' > trigger
+ *     - 'traceoff' is both cmd and glob
+ *     - there is no param_and_filter
+ *     - there is no param
+ *     - there is no filter
+ *
+ * There are a few different categories of event trigger covered by
+ * these helpers:
+ *
+ *  - triggers that don't require a parameter e.g. traceon
+ *  - triggers that do require a parameter e.g. enable_event and hist
+ *  - triggers that though they may not require a param may support an
+ *    optional 'n' param (n = number of times the trigger should fire)
+ *    e.g.: traceon:5 or enable_event:sys:event:n
+ *  - triggers that do not support an 'n' param e.g. hist
+ *
+ * These functions can be used or ignored as necessary - it all
+ * depends on the complexity of the trigger, and the granularity of
+ * the functions supported reflects the fact that some implementations
+ * may need to customize certain aspects of their implementations and
+ * won't need certain functions.  For instance, the hist trigger
+ * implementation doesn't use event_trigger_separate_filter() because
+ * it has special requirements for handling the filter.
+ */
+
+/**
+ * event_trigger_check_remove - check whether an event trigger specifies remove
+ * @glob: The trigger command string, with optional remove(!) operator
+ *
+ * The event trigger callback implementations pass in 'glob' as a
+ * parameter.  This is the command name either with or without a
+ * remove(!)  operator.  This function simply parses the glob and
+ * determines whether the command corresponds to a trigger removal or
+ * a trigger addition.
+ *
+ * Return: true if this is a remove command, false otherwise
+ */
+bool event_trigger_check_remove(const char *glob)
+{
+	return (glob && glob[0] == '!') ? true : false;
+}
+
+/**
+ * event_trigger_empty_param - check whether the param is empty
+ * @param: The trigger param string
+ *
+ * The event trigger callback implementations pass in 'param' as a
+ * parameter.  This corresponds to the string following the command
+ * name minus the command name.  This function can be called by a
+ * callback implementation for any command that requires a param; a
+ * callback that doesn't require a param can ignore it.
+ *
+ * Return: true if this is an empty param, false otherwise
+ */
+bool event_trigger_empty_param(const char *param)
+{
+	return !param;
+}
+
+/**
+ * event_trigger_separate_filter - separate an event trigger from a filter
+ * @param_and_filter: String containing trigger and possibly filter
+ * @param: outparam, will be filled with a pointer to the trigger
+ * @filter: outparam, will be filled with a pointer to the filter
+ * @param_required: Specifies whether or not the param string is required
+ *
+ * Given a param string of the form '[trigger] [if filter]', this
+ * function separates the filter from the trigger and returns the
+ * trigger in @param and the filter in @filter.  Either the @param
+ * or the @filter may be set to NULL by this function - if not set to
+ * NULL, they will contain strings corresponding to the trigger and
+ * filter.
+ *
+ * There are two cases that need to be handled with respect to the
+ * passed-in param: either the param is required, or it is not
+ * required.  If @param_required is set, and there's no param, it will
+ * return -EINVAL.  If @param_required is not set and there's a param
+ * that starts with a number, that corresponds to the case of a
+ * trigger with :n (n = number of times the trigger should fire) and
+ * the parsing continues normally; otherwise the function just returns
+ * and assumes param just contains a filter and there's nothing else
+ * to do.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_separate_filter(char *param_and_filter, char **param,
+				  char **filter, bool param_required)
+{
+	int ret = 0;
+
+	*param = *filter = NULL;
+
+	if (!param_and_filter) {
+		if (param_required)
+			ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Here we check for an optional param. The only legal
+	 * optional param is :n, and if that's the case, continue
+	 * below. Otherwise we assume what's left is a filter and
+	 * return it as the filter string for the caller to deal with.
+	 */
+	if (!param_required && param_and_filter && !isdigit(param_and_filter[0])) {
+		*filter = param_and_filter;
+		goto out;
+	}
+
+	/*
+	 * Separate the param from the filter (param [if filter]).
+	 * Here we have either an optional :n param or a required
+	 * param and an optional filter.
+	 */
+	*param = strsep(&param_and_filter, " \t");
+
+	/*
+	 * Here we have a filter, though it may be empty.
+	 */
+	if (param_and_filter) {
+		*filter = skip_spaces(param_and_filter);
+		if (!**filter)
+			*filter = NULL;
+	}
+out:
+	return ret;
+}
+
+/**
+ * event_trigger_alloc - allocate and init event_trigger_data for a trigger
+ * @cmd_ops: The event_command operations for the trigger
+ * @cmd: The cmd string
+ * @param: The param string
+ * @private_data: User data to associate with the event trigger
+ *
+ * Allocate an event_trigger_data instance and initialize it.  The
+ * @cmd_ops are used along with the @cmd and @param to get the
+ * trigger_ops to assign to the event_trigger_data.  @private_data can
+ * also be passed in and associated with the event_trigger_data.
+ *
+ * Use event_trigger_free() to free an event_trigger_data object.
+ *
+ * Return: The trigger_data object success, NULL otherwise
+ */
+struct event_trigger_data *event_trigger_alloc(struct event_command *cmd_ops,
+					       char *cmd,
+					       char *param,
+					       void *private_data)
+{
+	struct event_trigger_data *trigger_data;
+	struct event_trigger_ops *trigger_ops;
+
+	trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
+
+	trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
+	if (!trigger_data)
+		return NULL;
+
+	trigger_data->count = -1;
+	trigger_data->ops = trigger_ops;
+	trigger_data->cmd_ops = cmd_ops;
+	trigger_data->private_data = private_data;
+
+	INIT_LIST_HEAD(&trigger_data->list);
+	INIT_LIST_HEAD(&trigger_data->named_list);
+	RCU_INIT_POINTER(trigger_data->filter, NULL);
+
+	return trigger_data;
+}
+
+/**
+ * event_trigger_parse_num - parse and return the number param for a trigger
+ * @param: The param string
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Parse the :n (n = number of times the trigger should fire) param
+ * and set the count variable in the trigger_data to the parsed count.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_parse_num(char *param,
+			    struct event_trigger_data *trigger_data)
+{
+	char *number;
+	int ret = 0;
+
+	if (param) {
+		number = strsep(&param, ":");
+
+		if (!strlen(number))
+			return -EINVAL;
+
+		/*
+		 * We use the callback data field (which is a pointer)
+		 * as our counter.
+		 */
+		ret = kstrtoul(number, 0, &trigger_data->count);
+	}
+
+	return ret;
+}
+
+/**
+ * event_trigger_set_filter - set an event trigger's filter
+ * @cmd_ops: The event_command operations for the trigger
+ * @file: The event file for the trigger's event
+ * @param: The string containing the filter
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Set the filter for the trigger.  If the filter is NULL, just return
+ * without error.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_set_filter(struct event_command *cmd_ops,
+			     struct trace_event_file *file,
+			     char *param,
+			     struct event_trigger_data *trigger_data)
+{
+	if (param && cmd_ops->set_filter)
+		return cmd_ops->set_filter(param, trigger_data, file);
+
+	return 0;
+}
+
+/**
+ * event_trigger_reset_filter - reset an event trigger's filter
+ * @cmd_ops: The event_command operations for the trigger
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Reset the filter for the trigger to no filter.
+ */
+void event_trigger_reset_filter(struct event_command *cmd_ops,
+				struct event_trigger_data *trigger_data)
+{
+	if (cmd_ops->set_filter)
+		cmd_ops->set_filter(NULL, trigger_data, NULL);
+}
+
+/**
+ * event_trigger_register - register an event trigger
+ * @cmd_ops: The event_command operations for the trigger
+ * @file: The event file for the trigger's event
+ * @glob: The trigger command string, with optional remove(!) operator
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Register an event trigger.  The @cmd_ops are used to call the
+ * cmd_ops->reg() function which actually does the registration.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_register(struct event_command *cmd_ops,
+			   struct trace_event_file *file,
+			   char *glob,
+			   struct event_trigger_data *trigger_data)
+{
+	return cmd_ops->reg(glob, trigger_data, file);
+}
+
+/**
+ * event_trigger_unregister - unregister an event trigger
+ * @cmd_ops: The event_command operations for the trigger
+ * @file: The event file for the trigger's event
+ * @glob: The trigger command string, with optional remove(!) operator
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Unregister an event trigger.  The @cmd_ops are used to call the
+ * cmd_ops->unreg() function which actually does the unregistration.
+ */
+void event_trigger_unregister(struct event_command *cmd_ops,
+			      struct trace_event_file *file,
+			      char *glob,
+			      struct event_trigger_data *trigger_data)
+{
+	cmd_ops->unreg(glob, trigger_data, file);
+}
+
+/*
+ * End event trigger parsing helper functions.
+ */
+
+/**
+ * event_trigger_parse - Generic event_command @parse implementation
+ * @cmd_ops: The command ops, used for trigger registration
+ * @file: The trace_event_file associated with the event
+ * @glob: The raw string used to register the trigger
+ * @cmd: The cmd portion of the string used to register the trigger
+ * @param_and_filter: The param and filter portion of the string used to register the trigger
+ *
+ * Common implementation for event command parsing and trigger
+ * instantiation.
+ *
+ * Usually used directly as the @parse method in event command
+ * implementations.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+static int
+event_trigger_parse(struct event_command *cmd_ops,
+		    struct trace_event_file *file,
+		    char *glob, char *cmd, char *param_and_filter)
+{
+	struct event_trigger_data *trigger_data;
+	char *param, *filter;
+	bool remove;
+	int ret;
+
+	remove = event_trigger_check_remove(glob);
+
+	ret = event_trigger_separate_filter(param_and_filter, &param, &filter, false);
+	if (ret)
+		return ret;
+
+	ret = -ENOMEM;
+	trigger_data = event_trigger_alloc(cmd_ops, cmd, param, file);
+	if (!trigger_data)
+		goto out;
+
+	if (remove) {
+		event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
+		kfree(trigger_data);
+		ret = 0;
+		goto out;
+	}
+
+	ret = event_trigger_parse_num(param, trigger_data);
+	if (ret)
+		goto out_free;
+
+	ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
+	if (ret < 0)
+		goto out_free;
+
+	/* Up the trigger_data count to make sure reg doesn't free it on failure */
+	event_trigger_init(trigger_data);
+
+	ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
+	if (ret)
+		goto out_free;
+
+	/* Down the counter of trigger_data or free it if not used anymore */
+	event_trigger_free(trigger_data);
+ out:
+	return ret;
+
+ out_free:
+	event_trigger_reset_filter(cmd_ops, trigger_data);
+	kfree(trigger_data);
+	goto out;
+}
+
+/**
+ * set_trigger_filter - Generic event_command @set_filter implementation
+ * @filter_str: The filter string for the trigger, NULL to remove filter
+ * @trigger_data: Trigger-specific data
+ * @file: The trace_event_file associated with the event
+ *
+ * Common implementation for event command filter parsing and filter
+ * instantiation.
+ *
+ * Usually used directly as the @set_filter method in event command
+ * implementations.
+ *
+ * Also used to remove a filter (if filter_str = NULL).
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int set_trigger_filter(char *filter_str,
+		       struct event_trigger_data *trigger_data,
+		       struct trace_event_file *file)
+{
+	struct event_trigger_data *data = trigger_data;
+	struct event_filter *filter = NULL, *tmp;
+	int ret = -EINVAL;
+	char *s;
+
+	if (!filter_str) /* clear the current filter */
+		goto assign;
+
+	s = strsep(&filter_str, " \t");
+
+	if (!strlen(s) || strcmp(s, "if") != 0)
+		goto out;
+
+	if (!filter_str)
+		goto out;
+
+	/* The filter is for the 'trigger' event, not the triggered event */
+	ret = create_event_filter(file->tr, file->event_call,
+				  filter_str, false, &filter);
+	/*
+	 * If create_event_filter() fails, filter still needs to be freed.
+	 * Which the calling code will do with data->filter.
+	 */
+ assign:
+	tmp = rcu_access_pointer(data->filter);
+
+	rcu_assign_pointer(data->filter, filter);
+
+	if (tmp) {
+		/* Make sure the call is done with the filter */
+		tracepoint_synchronize_unregister();
+		free_event_filter(tmp);
+	}
+
+	kfree(data->filter_str);
+	data->filter_str = NULL;
+
+	if (filter_str) {
+		data->filter_str = kstrdup(filter_str, GFP_KERNEL);
+		if (!data->filter_str) {
+			free_event_filter(rcu_access_pointer(data->filter));
+			data->filter = NULL;
+			ret = -ENOMEM;
+		}
+	}
+ out:
+	return ret;
+}
+
+static LIST_HEAD(named_triggers);
+
+/**
+ * find_named_trigger - Find the common named trigger associated with @name
+ * @name: The name of the set of named triggers to find the common data for
+ *
+ * Named triggers are sets of triggers that share a common set of
+ * trigger data.  The first named trigger registered with a given name
+ * owns the common trigger data that the others subsequently
+ * registered with the same name will reference.  This function
+ * returns the common trigger data associated with that first
+ * registered instance.
+ *
+ * Return: the common trigger data for the given named trigger on
+ * success, NULL otherwise.
+ */
+struct event_trigger_data *find_named_trigger(const char *name)
+{
+	struct event_trigger_data *data;
+
+	if (!name)
+		return NULL;
+
+	list_for_each_entry(data, &named_triggers, named_list) {
+		if (data->named_data)
+			continue;
+		if (strcmp(data->name, name) == 0)
+			return data;
+	}
+
+	return NULL;
+}
+
+/**
+ * is_named_trigger - determine if a given trigger is a named trigger
+ * @test: The trigger data to test
+ *
+ * Return: true if 'test' is a named trigger, false otherwise.
+ */
+bool is_named_trigger(struct event_trigger_data *test)
+{
+	struct event_trigger_data *data;
+
+	list_for_each_entry(data, &named_triggers, named_list) {
+		if (test == data)
+			return true;
+	}
+
+	return false;
+}
+
+/**
+ * save_named_trigger - save the trigger in the named trigger list
+ * @name: The name of the named trigger set
+ * @data: The trigger data to save
+ *
+ * Return: 0 if successful, negative error otherwise.
+ */
+int save_named_trigger(const char *name, struct event_trigger_data *data)
+{
+	data->name = kstrdup(name, GFP_KERNEL);
+	if (!data->name)
+		return -ENOMEM;
+
+	list_add(&data->named_list, &named_triggers);
+
+	return 0;
+}
+
+/**
+ * del_named_trigger - delete a trigger from the named trigger list
+ * @data: The trigger data to delete
+ */
+void del_named_trigger(struct event_trigger_data *data)
+{
+	kfree(data->name);
+	data->name = NULL;
+
+	list_del(&data->named_list);
+}
+
+static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
+{
+	struct event_trigger_data *test;
+
+	list_for_each_entry(test, &named_triggers, named_list) {
+		if (strcmp(test->name, data->name) == 0) {
+			if (pause) {
+				test->paused_tmp = test->paused;
+				test->paused = true;
+			} else {
+				test->paused = test->paused_tmp;
+			}
+		}
+	}
+}
+
+/**
+ * pause_named_trigger - Pause all named triggers with the same name
+ * @data: The trigger data of a named trigger to pause
+ *
+ * Pauses a named trigger along with all other triggers having the
+ * same name.  Because named triggers share a common set of data,
+ * pausing only one is meaningless, so pausing one named trigger needs
+ * to pause all triggers with the same name.
+ */
+void pause_named_trigger(struct event_trigger_data *data)
+{
+	__pause_named_trigger(data, true);
+}
+
+/**
+ * unpause_named_trigger - Un-pause all named triggers with the same name
+ * @data: The trigger data of a named trigger to unpause
+ *
+ * Un-pauses a named trigger along with all other triggers having the
+ * same name.  Because named triggers share a common set of data,
+ * unpausing only one is meaningless, so unpausing one named trigger
+ * needs to unpause all triggers with the same name.
+ */
+void unpause_named_trigger(struct event_trigger_data *data)
+{
+	__pause_named_trigger(data, false);
+}
+
+/**
+ * set_named_trigger_data - Associate common named trigger data
+ * @data: The trigger data to associate
+ * @named_data: The common named trigger to be associated
+ *
+ * Named triggers are sets of triggers that share a common set of
+ * trigger data.  The first named trigger registered with a given name
+ * owns the common trigger data that the others subsequently
+ * registered with the same name will reference.  This function
+ * associates the common trigger data from the first trigger with the
+ * given trigger.
+ */
+void set_named_trigger_data(struct event_trigger_data *data,
+			    struct event_trigger_data *named_data)
+{
+	data->named_data = named_data;
+}
+
+struct event_trigger_data *
+get_named_trigger_data(struct event_trigger_data *data)
+{
+	return data->named_data;
+}
+
+static void
+traceon_trigger(struct event_trigger_data *data,
+		struct trace_buffer *buffer, void *rec,
+		struct ring_buffer_event *event)
+{
+	struct trace_event_file *file = data->private_data;
+
+	if (file) {
+		if (tracer_tracing_is_on(file->tr))
+			return;
+
+		tracer_tracing_on(file->tr);
+		return;
+	}
+
+	if (tracing_is_on())
+		return;
+
+	tracing_on();
+}
+
+static void
+traceon_count_trigger(struct event_trigger_data *data,
+		      struct trace_buffer *buffer, void *rec,
+		      struct ring_buffer_event *event)
+{
+	struct trace_event_file *file = data->private_data;
+
+	if (file) {
+		if (tracer_tracing_is_on(file->tr))
+			return;
+	} else {
+		if (tracing_is_on())
+			return;
+	}
+
+	if (!data->count)
+		return;
+
+	if (data->count != -1)
+		(data->count)--;
+
+	if (file)
+		tracer_tracing_on(file->tr);
+	else
+		tracing_on();
+}
+
+static void
+traceoff_trigger(struct event_trigger_data *data,
+		 struct trace_buffer *buffer, void *rec,
+		 struct ring_buffer_event *event)
+{
+	struct trace_event_file *file = data->private_data;
+
+	if (file) {
+		if (!tracer_tracing_is_on(file->tr))
+			return;
+
+		tracer_tracing_off(file->tr);
+		return;
+	}
+
+	if (!tracing_is_on())
+		return;
+
+	tracing_off();
+}
+
+static void
+traceoff_count_trigger(struct event_trigger_data *data,
+		       struct trace_buffer *buffer, void *rec,
+		       struct ring_buffer_event *event)
+{
+	struct trace_event_file *file = data->private_data;
+
+	if (file) {
+		if (!tracer_tracing_is_on(file->tr))
+			return;
+	} else {
+		if (!tracing_is_on())
+			return;
+	}
+
+	if (!data->count)
+		return;
+
+	if (data->count != -1)
+		(data->count)--;
+
+	if (file)
+		tracer_tracing_off(file->tr);
+	else
+		tracing_off();
+}
+
+static int
+traceon_trigger_print(struct seq_file *m, struct event_trigger_data *data)
+{
+	return event_trigger_print("traceon", m, (void *)data->count,
+				   data->filter_str);
+}
+
+static int
+traceoff_trigger_print(struct seq_file *m, struct event_trigger_data *data)
+{
+	return event_trigger_print("traceoff", m, (void *)data->count,
+				   data->filter_str);
+}
+
+static struct event_trigger_ops traceon_trigger_ops = {
+	.trigger		= traceon_trigger,
+	.print			= traceon_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_trigger_free,
+};
+
+static struct event_trigger_ops traceon_count_trigger_ops = {
+	.trigger		= traceon_count_trigger,
+	.print			= traceon_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_trigger_free,
+};
+
+static struct event_trigger_ops traceoff_trigger_ops = {
+	.trigger		= traceoff_trigger,
+	.print			= traceoff_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_trigger_free,
+};
+
+static struct event_trigger_ops traceoff_count_trigger_ops = {
+	.trigger		= traceoff_count_trigger,
+	.print			= traceoff_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_trigger_free,
+};
+
+static struct event_trigger_ops *
+onoff_get_trigger_ops(char *cmd, char *param)
+{
+	struct event_trigger_ops *ops;
+
+	/* we register both traceon and traceoff to this callback */
+	if (strcmp(cmd, "traceon") == 0)
+		ops = param ? &traceon_count_trigger_ops :
+			&traceon_trigger_ops;
+	else
+		ops = param ? &traceoff_count_trigger_ops :
+			&traceoff_trigger_ops;
+
+	return ops;
+}
+
+static struct event_command trigger_traceon_cmd = {
+	.name			= "traceon",
+	.trigger_type		= ETT_TRACE_ONOFF,
+	.parse			= event_trigger_parse,
+	.reg			= register_trigger,
+	.unreg			= unregister_trigger,
+	.get_trigger_ops	= onoff_get_trigger_ops,
+	.set_filter		= set_trigger_filter,
+};
+
+static struct event_command trigger_traceoff_cmd = {
+	.name			= "traceoff",
+	.trigger_type		= ETT_TRACE_ONOFF,
+	.flags			= EVENT_CMD_FL_POST_TRIGGER,
+	.parse			= event_trigger_parse,
+	.reg			= register_trigger,
+	.unreg			= unregister_trigger,
+	.get_trigger_ops	= onoff_get_trigger_ops,
+	.set_filter		= set_trigger_filter,
+};
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+static void
+snapshot_trigger(struct event_trigger_data *data,
+		 struct trace_buffer *buffer, void *rec,
+		 struct ring_buffer_event *event)
+{
+	struct trace_event_file *file = data->private_data;
+
+	if (file)
+		tracing_snapshot_instance(file->tr);
+	else
+		tracing_snapshot();
+}
+
+static void
+snapshot_count_trigger(struct event_trigger_data *data,
+		       struct trace_buffer *buffer, void *rec,
+		       struct ring_buffer_event *event)
+{
+	if (!data->count)
+		return;
+
+	if (data->count != -1)
+		(data->count)--;
+
+	snapshot_trigger(data, buffer, rec, event);
+}
+
+static int
+register_snapshot_trigger(char *glob,
+			  struct event_trigger_data *data,
+			  struct trace_event_file *file)
+{
+	if (tracing_alloc_snapshot_instance(file->tr) != 0)
+		return 0;
+
+	return register_trigger(glob, data, file);
+}
+
+static int
+snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data)
+{
+	return event_trigger_print("snapshot", m, (void *)data->count,
+				   data->filter_str);
+}
+
+static struct event_trigger_ops snapshot_trigger_ops = {
+	.trigger		= snapshot_trigger,
+	.print			= snapshot_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_trigger_free,
+};
+
+static struct event_trigger_ops snapshot_count_trigger_ops = {
+	.trigger		= snapshot_count_trigger,
+	.print			= snapshot_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_trigger_free,
+};
+
+static struct event_trigger_ops *
+snapshot_get_trigger_ops(char *cmd, char *param)
+{
+	return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
+}
+
+static struct event_command trigger_snapshot_cmd = {
+	.name			= "snapshot",
+	.trigger_type		= ETT_SNAPSHOT,
+	.parse			= event_trigger_parse,
+	.reg			= register_snapshot_trigger,
+	.unreg			= unregister_trigger,
+	.get_trigger_ops	= snapshot_get_trigger_ops,
+	.set_filter		= set_trigger_filter,
+};
+
+static __init int register_trigger_snapshot_cmd(void)
+{
+	int ret;
+
+	ret = register_event_command(&trigger_snapshot_cmd);
+	WARN_ON(ret < 0);
+
+	return ret;
+}
+#else
+static __init int register_trigger_snapshot_cmd(void) { return 0; }
+#endif /* CONFIG_TRACER_SNAPSHOT */
+
+#ifdef CONFIG_STACKTRACE
+#ifdef CONFIG_UNWINDER_ORC
+/* Skip 2:
+ *   event_triggers_post_call()
+ *   trace_event_raw_event_xxx()
+ */
+# define STACK_SKIP 2
+#else
+/*
+ * Skip 4:
+ *   stacktrace_trigger()
+ *   event_triggers_post_call()
+ *   trace_event_buffer_commit()
+ *   trace_event_raw_event_xxx()
+ */
+#define STACK_SKIP 4
+#endif
+
+static void
+stacktrace_trigger(struct event_trigger_data *data,
+		   struct trace_buffer *buffer,  void *rec,
+		   struct ring_buffer_event *event)
+{
+	struct trace_event_file *file = data->private_data;
+
+	if (file)
+		__trace_stack(file->tr, tracing_gen_ctx(), STACK_SKIP);
+	else
+		trace_dump_stack(STACK_SKIP);
+}
+
+static void
+stacktrace_count_trigger(struct event_trigger_data *data,
+			 struct trace_buffer *buffer, void *rec,
+			 struct ring_buffer_event *event)
+{
+	if (!data->count)
+		return;
+
+	if (data->count != -1)
+		(data->count)--;
+
+	stacktrace_trigger(data, buffer, rec, event);
+}
+
+static int
+stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data)
+{
+	return event_trigger_print("stacktrace", m, (void *)data->count,
+				   data->filter_str);
+}
+
+static struct event_trigger_ops stacktrace_trigger_ops = {
+	.trigger		= stacktrace_trigger,
+	.print			= stacktrace_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_trigger_free,
+};
+
+static struct event_trigger_ops stacktrace_count_trigger_ops = {
+	.trigger		= stacktrace_count_trigger,
+	.print			= stacktrace_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_trigger_free,
+};
+
+static struct event_trigger_ops *
+stacktrace_get_trigger_ops(char *cmd, char *param)
+{
+	return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
+}
+
+static struct event_command trigger_stacktrace_cmd = {
+	.name			= "stacktrace",
+	.trigger_type		= ETT_STACKTRACE,
+	.flags			= EVENT_CMD_FL_POST_TRIGGER,
+	.parse			= event_trigger_parse,
+	.reg			= register_trigger,
+	.unreg			= unregister_trigger,
+	.get_trigger_ops	= stacktrace_get_trigger_ops,
+	.set_filter		= set_trigger_filter,
+};
+
+static __init int register_trigger_stacktrace_cmd(void)
+{
+	int ret;
+
+	ret = register_event_command(&trigger_stacktrace_cmd);
+	WARN_ON(ret < 0);
+
+	return ret;
+}
+#else
+static __init int register_trigger_stacktrace_cmd(void) { return 0; }
+#endif /* CONFIG_STACKTRACE */
+
+static __init void unregister_trigger_traceon_traceoff_cmds(void)
+{
+	unregister_event_command(&trigger_traceon_cmd);
+	unregister_event_command(&trigger_traceoff_cmd);
+}
+
+static void
+event_enable_trigger(struct event_trigger_data *data,
+		     struct trace_buffer *buffer,  void *rec,
+		     struct ring_buffer_event *event)
+{
+	struct enable_trigger_data *enable_data = data->private_data;
+
+	if (enable_data->enable)
+		clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
+	else
+		set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
+}
+
+static void
+event_enable_count_trigger(struct event_trigger_data *data,
+			   struct trace_buffer *buffer,  void *rec,
+			   struct ring_buffer_event *event)
+{
+	struct enable_trigger_data *enable_data = data->private_data;
+
+	if (!data->count)
+		return;
+
+	/* Skip if the event is in a state we want to switch to */
+	if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
+		return;
+
+	if (data->count != -1)
+		(data->count)--;
+
+	event_enable_trigger(data, buffer, rec, event);
+}
+
+int event_enable_trigger_print(struct seq_file *m,
+			       struct event_trigger_data *data)
+{
+	struct enable_trigger_data *enable_data = data->private_data;
+
+	seq_printf(m, "%s:%s:%s",
+		   enable_data->hist ?
+		   (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
+		   (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
+		   enable_data->file->event_call->class->system,
+		   trace_event_name(enable_data->file->event_call));
+
+	if (data->count == -1)
+		seq_puts(m, ":unlimited");
+	else
+		seq_printf(m, ":count=%ld", data->count);
+
+	if (data->filter_str)
+		seq_printf(m, " if %s\n", data->filter_str);
+	else
+		seq_putc(m, '\n');
+
+	return 0;
+}
+
+void event_enable_trigger_free(struct event_trigger_data *data)
+{
+	struct enable_trigger_data *enable_data = data->private_data;
+
+	if (WARN_ON_ONCE(data->ref <= 0))
+		return;
+
+	data->ref--;
+	if (!data->ref) {
+		/* Remove the SOFT_MODE flag */
+		trace_event_enable_disable(enable_data->file, 0, 1);
+		trace_event_put_ref(enable_data->file->event_call);
+		trigger_data_free(data);
+		kfree(enable_data);
+	}
+}
+
+static struct event_trigger_ops event_enable_trigger_ops = {
+	.trigger		= event_enable_trigger,
+	.print			= event_enable_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_enable_trigger_free,
+};
+
+static struct event_trigger_ops event_enable_count_trigger_ops = {
+	.trigger		= event_enable_count_trigger,
+	.print			= event_enable_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_enable_trigger_free,
+};
+
+static struct event_trigger_ops event_disable_trigger_ops = {
+	.trigger		= event_enable_trigger,
+	.print			= event_enable_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_enable_trigger_free,
+};
+
+static struct event_trigger_ops event_disable_count_trigger_ops = {
+	.trigger		= event_enable_count_trigger,
+	.print			= event_enable_trigger_print,
+	.init			= event_trigger_init,
+	.free			= event_enable_trigger_free,
+};
+
+int event_enable_trigger_parse(struct event_command *cmd_ops,
+			       struct trace_event_file *file,
+			       char *glob, char *cmd, char *param_and_filter)
+{
+	struct trace_event_file *event_enable_file;
+	struct enable_trigger_data *enable_data;
+	struct event_trigger_data *trigger_data;
+	struct trace_array *tr = file->tr;
+	char *param, *filter;
+	bool enable, remove;
+	const char *system;
+	const char *event;
+	bool hist = false;
+	int ret;
+
+	remove = event_trigger_check_remove(glob);
+
+	if (event_trigger_empty_param(param_and_filter))
+		return -EINVAL;
+
+	ret = event_trigger_separate_filter(param_and_filter, &param, &filter, true);
+	if (ret)
+		return ret;
+
+	system = strsep(&param, ":");
+	if (!param)
+		return -EINVAL;
+
+	event = strsep(&param, ":");
+
+	ret = -EINVAL;
+	event_enable_file = find_event_file(tr, system, event);
+	if (!event_enable_file)
+		goto out;
+
+#ifdef CONFIG_HIST_TRIGGERS
+	hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
+		(strcmp(cmd, DISABLE_HIST_STR) == 0));
+
+	enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
+		  (strcmp(cmd, ENABLE_HIST_STR) == 0));
+#else
+	enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
+#endif
+	ret = -ENOMEM;
+
+	enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
+	if (!enable_data)
+		goto out;
+
+	enable_data->hist = hist;
+	enable_data->enable = enable;
+	enable_data->file = event_enable_file;
+
+	trigger_data = event_trigger_alloc(cmd_ops, cmd, param, enable_data);
+	if (!trigger_data) {
+		kfree(enable_data);
+		goto out;
+	}
+
+	if (remove) {
+		event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
+		kfree(trigger_data);
+		kfree(enable_data);
+		ret = 0;
+		goto out;
+	}
+
+	/* Up the trigger_data count to make sure nothing frees it on failure */
+	event_trigger_init(trigger_data);
+
+	ret = event_trigger_parse_num(param, trigger_data);
+	if (ret)
+		goto out_free;
+
+	ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
+	if (ret < 0)
+		goto out_free;
+
+	/* Don't let event modules unload while probe registered */
+	ret = trace_event_try_get_ref(event_enable_file->event_call);
+	if (!ret) {
+		ret = -EBUSY;
+		goto out_free;
+	}
+
+	ret = trace_event_enable_disable(event_enable_file, 1, 1);
+	if (ret < 0)
+		goto out_put;
+
+	ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
+	if (ret)
+		goto out_disable;
+
+	event_trigger_free(trigger_data);
+ out:
+	return ret;
+ out_disable:
+	trace_event_enable_disable(event_enable_file, 0, 1);
+ out_put:
+	trace_event_put_ref(event_enable_file->event_call);
+ out_free:
+	event_trigger_reset_filter(cmd_ops, trigger_data);
+	event_trigger_free(trigger_data);
+	kfree(enable_data);
+
+	goto out;
+}
+
+int event_enable_register_trigger(char *glob,
+				  struct event_trigger_data *data,
+				  struct trace_event_file *file)
+{
+	struct enable_trigger_data *enable_data = data->private_data;
+	struct enable_trigger_data *test_enable_data;
+	struct event_trigger_data *test;
+	int ret = 0;
+
+	lockdep_assert_held(&event_mutex);
+
+	list_for_each_entry(test, &file->triggers, list) {
+		test_enable_data = test->private_data;
+		if (test_enable_data &&
+		    (test->cmd_ops->trigger_type ==
+		     data->cmd_ops->trigger_type) &&
+		    (test_enable_data->file == enable_data->file)) {
+			ret = -EEXIST;
+			goto out;
+		}
+	}
+
+	if (data->ops->init) {
+		ret = data->ops->init(data);
+		if (ret < 0)
+			goto out;
+	}
+
+	list_add_rcu(&data->list, &file->triggers);
+
+	update_cond_flag(file);
+	ret = trace_event_trigger_enable_disable(file, 1);
+	if (ret < 0) {
+		list_del_rcu(&data->list);
+		update_cond_flag(file);
+	}
+out:
+	return ret;
+}
+
+void event_enable_unregister_trigger(char *glob,
+				     struct event_trigger_data *test,
+				     struct trace_event_file *file)
+{
+	struct enable_trigger_data *test_enable_data = test->private_data;
+	struct event_trigger_data *data = NULL, *iter;
+	struct enable_trigger_data *enable_data;
+
+	lockdep_assert_held(&event_mutex);
+
+	list_for_each_entry(iter, &file->triggers, list) {
+		enable_data = iter->private_data;
+		if (enable_data &&
+		    (iter->cmd_ops->trigger_type ==
+		     test->cmd_ops->trigger_type) &&
+		    (enable_data->file == test_enable_data->file)) {
+			data = iter;
+			list_del_rcu(&data->list);
+			trace_event_trigger_enable_disable(file, 0);
+			update_cond_flag(file);
+			break;
+		}
+	}
+
+	if (data && data->ops->free)
+		data->ops->free(data);
+}
+
+static struct event_trigger_ops *
+event_enable_get_trigger_ops(char *cmd, char *param)
+{
+	struct event_trigger_ops *ops;
+	bool enable;
+
+#ifdef CONFIG_HIST_TRIGGERS
+	enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
+		  (strcmp(cmd, ENABLE_HIST_STR) == 0));
+#else
+	enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
+#endif
+	if (enable)
+		ops = param ? &event_enable_count_trigger_ops :
+			&event_enable_trigger_ops;
+	else
+		ops = param ? &event_disable_count_trigger_ops :
+			&event_disable_trigger_ops;
+
+	return ops;
+}
+
+static struct event_command trigger_enable_cmd = {
+	.name			= ENABLE_EVENT_STR,
+	.trigger_type		= ETT_EVENT_ENABLE,
+	.parse			= event_enable_trigger_parse,
+	.reg			= event_enable_register_trigger,
+	.unreg			= event_enable_unregister_trigger,
+	.get_trigger_ops	= event_enable_get_trigger_ops,
+	.set_filter		= set_trigger_filter,
+};
+
+static struct event_command trigger_disable_cmd = {
+	.name			= DISABLE_EVENT_STR,
+	.trigger_type		= ETT_EVENT_ENABLE,
+	.parse			= event_enable_trigger_parse,
+	.reg			= event_enable_register_trigger,
+	.unreg			= event_enable_unregister_trigger,
+	.get_trigger_ops	= event_enable_get_trigger_ops,
+	.set_filter		= set_trigger_filter,
+};
+
+static __init void unregister_trigger_enable_disable_cmds(void)
+{
+	unregister_event_command(&trigger_enable_cmd);
+	unregister_event_command(&trigger_disable_cmd);
+}
+
+static __init int register_trigger_enable_disable_cmds(void)
+{
+	int ret;
+
+	ret = register_event_command(&trigger_enable_cmd);
+	if (WARN_ON(ret < 0))
+		return ret;
+	ret = register_event_command(&trigger_disable_cmd);
+	if (WARN_ON(ret < 0))
+		unregister_trigger_enable_disable_cmds();
+
+	return ret;
+}
+
+static __init int register_trigger_traceon_traceoff_cmds(void)
+{
+	int ret;
+
+	ret = register_event_command(&trigger_traceon_cmd);
+	if (WARN_ON(ret < 0))
+		return ret;
+	ret = register_event_command(&trigger_traceoff_cmd);
+	if (WARN_ON(ret < 0))
+		unregister_trigger_traceon_traceoff_cmds();
+
+	return ret;
+}
+
+__init int register_trigger_cmds(void)
+{
+	register_trigger_traceon_traceoff_cmds();
+	register_trigger_snapshot_cmd();
+	register_trigger_stacktrace_cmd();
+	register_trigger_enable_disable_cmds();
+	register_trigger_hist_enable_disable_cmds();
+	register_trigger_hist_cmd();
+
+	return 0;
+}
diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
new file mode 100644
index 000000000..bff699fe9
--- /dev/null
+++ b/kernel/trace/trace_events_user.c
@@ -0,0 +1,1922 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021, Microsoft Corporation.
+ *
+ * Authors:
+ *   Beau Belgrave <beaub@linux.microsoft.com>
+ */
+
+#include <linux/bitmap.h>
+#include <linux/cdev.h>
+#include <linux/hashtable.h>
+#include <linux/list.h>
+#include <linux/io.h>
+#include <linux/uio.h>
+#include <linux/ioctl.h>
+#include <linux/jhash.h>
+#include <linux/refcount.h>
+#include <linux/trace_events.h>
+#include <linux/tracefs.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+/* Reminder to move to uapi when everything works */
+#ifdef CONFIG_COMPILE_TEST
+#include <linux/user_events.h>
+#else
+#include <uapi/linux/user_events.h>
+#endif
+#include "trace.h"
+#include "trace_dynevent.h"
+
+#define USER_EVENTS_PREFIX_LEN (sizeof(USER_EVENTS_PREFIX)-1)
+
+#define FIELD_DEPTH_TYPE 0
+#define FIELD_DEPTH_NAME 1
+#define FIELD_DEPTH_SIZE 2
+
+/*
+ * Limits how many trace_event calls user processes can create:
+ * Must be a power of two of PAGE_SIZE.
+ */
+#define MAX_PAGE_ORDER 0
+#define MAX_PAGES (1 << MAX_PAGE_ORDER)
+#define MAX_BYTES (MAX_PAGES * PAGE_SIZE)
+#define MAX_EVENTS (MAX_BYTES * 8)
+
+/* Limit how long of an event name plus args within the subsystem. */
+#define MAX_EVENT_DESC 512
+#define EVENT_NAME(user_event) ((user_event)->tracepoint.name)
+#define MAX_FIELD_ARRAY_SIZE 1024
+
+/*
+ * The MAP_STATUS_* macros are used for taking a index and determining the
+ * appropriate byte and the bit in the byte to set/reset for an event.
+ *
+ * The lower 3 bits of the index decide which bit to set.
+ * The remaining upper bits of the index decide which byte to use for the bit.
+ *
+ * This is used when an event has a probe attached/removed to reflect live
+ * status of the event wanting tracing or not to user-programs via shared
+ * memory maps.
+ */
+#define MAP_STATUS_BYTE(index) ((index) >> 3)
+#define MAP_STATUS_MASK(index) BIT((index) & 7)
+
+/*
+ * Internal bits (kernel side only) to keep track of connected probes:
+ * These are used when status is requested in text form about an event. These
+ * bits are compared against an internal byte on the event to determine which
+ * probes to print out to the user.
+ *
+ * These do not reflect the mapped bytes between the user and kernel space.
+ */
+#define EVENT_STATUS_FTRACE BIT(0)
+#define EVENT_STATUS_PERF BIT(1)
+#define EVENT_STATUS_OTHER BIT(7)
+
+/*
+ * Stores the pages, tables, and locks for a group of events.
+ * Each logical grouping of events has its own group, with a
+ * matching page for status checks within user programs. This
+ * allows for isolation of events to user programs by various
+ * means.
+ */
+struct user_event_group {
+	struct page *pages;
+	char *register_page_data;
+	char *system_name;
+	struct hlist_node node;
+	struct mutex reg_mutex;
+	DECLARE_HASHTABLE(register_table, 8);
+	DECLARE_BITMAP(page_bitmap, MAX_EVENTS);
+};
+
+/* Group for init_user_ns mapping, top-most group */
+static struct user_event_group *init_group;
+
+/*
+ * Stores per-event properties, as users register events
+ * within a file a user_event might be created if it does not
+ * already exist. These are globally used and their lifetime
+ * is tied to the refcnt member. These cannot go away until the
+ * refcnt reaches one.
+ */
+struct user_event {
+	struct user_event_group *group;
+	struct tracepoint tracepoint;
+	struct trace_event_call call;
+	struct trace_event_class class;
+	struct dyn_event devent;
+	struct hlist_node node;
+	struct list_head fields;
+	struct list_head validators;
+	refcount_t refcnt;
+	int index;
+	int flags;
+	int min_size;
+	char status;
+};
+
+/*
+ * Stores per-file events references, as users register events
+ * within a file this structure is modified and freed via RCU.
+ * The lifetime of this struct is tied to the lifetime of the file.
+ * These are not shared and only accessible by the file that created it.
+ */
+struct user_event_refs {
+	struct rcu_head rcu;
+	int count;
+	struct user_event *events[];
+};
+
+struct user_event_file_info {
+	struct user_event_group *group;
+	struct user_event_refs *refs;
+};
+
+#define VALIDATOR_ENSURE_NULL (1 << 0)
+#define VALIDATOR_REL (1 << 1)
+
+struct user_event_validator {
+	struct list_head link;
+	int offset;
+	int flags;
+};
+
+typedef void (*user_event_func_t) (struct user_event *user, struct iov_iter *i,
+				   void *tpdata, bool *faulted);
+
+static int user_event_parse(struct user_event_group *group, char *name,
+			    char *args, char *flags,
+			    struct user_event **newuser);
+
+static u32 user_event_key(char *name)
+{
+	return jhash(name, strlen(name), 0);
+}
+
+static void set_page_reservations(char *pages, bool set)
+{
+	int page;
+
+	for (page = 0; page < MAX_PAGES; ++page) {
+		void *addr = pages + (PAGE_SIZE * page);
+
+		if (set)
+			SetPageReserved(virt_to_page(addr));
+		else
+			ClearPageReserved(virt_to_page(addr));
+	}
+}
+
+static void user_event_group_destroy(struct user_event_group *group)
+{
+	if (group->register_page_data)
+		set_page_reservations(group->register_page_data, false);
+
+	if (group->pages)
+		__free_pages(group->pages, MAX_PAGE_ORDER);
+
+	kfree(group->system_name);
+	kfree(group);
+}
+
+static char *user_event_group_system_name(struct user_namespace *user_ns)
+{
+	char *system_name;
+	int len = sizeof(USER_EVENTS_SYSTEM) + 1;
+
+	if (user_ns != &init_user_ns) {
+		/*
+		 * Unexpected at this point:
+		 * We only currently support init_user_ns.
+		 * When we enable more, this will trigger a failure so log.
+		 */
+		pr_warn("user_events: Namespace other than init_user_ns!\n");
+		return NULL;
+	}
+
+	system_name = kmalloc(len, GFP_KERNEL);
+
+	if (!system_name)
+		return NULL;
+
+	snprintf(system_name, len, "%s", USER_EVENTS_SYSTEM);
+
+	return system_name;
+}
+
+static inline struct user_event_group
+*user_event_group_from_user_ns(struct user_namespace *user_ns)
+{
+	if (user_ns == &init_user_ns)
+		return init_group;
+
+	return NULL;
+}
+
+static struct user_event_group *current_user_event_group(void)
+{
+	struct user_namespace *user_ns = current_user_ns();
+	struct user_event_group *group = NULL;
+
+	while (user_ns) {
+		group = user_event_group_from_user_ns(user_ns);
+
+		if (group)
+			break;
+
+		user_ns = user_ns->parent;
+	}
+
+	return group;
+}
+
+static struct user_event_group
+*user_event_group_create(struct user_namespace *user_ns)
+{
+	struct user_event_group *group;
+
+	group = kzalloc(sizeof(*group), GFP_KERNEL);
+
+	if (!group)
+		return NULL;
+
+	group->system_name = user_event_group_system_name(user_ns);
+
+	if (!group->system_name)
+		goto error;
+
+	group->pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, MAX_PAGE_ORDER);
+
+	if (!group->pages)
+		goto error;
+
+	group->register_page_data = page_address(group->pages);
+
+	set_page_reservations(group->register_page_data, true);
+
+	/* Zero all bits beside 0 (which is reserved for failures) */
+	bitmap_zero(group->page_bitmap, MAX_EVENTS);
+	set_bit(0, group->page_bitmap);
+
+	mutex_init(&group->reg_mutex);
+	hash_init(group->register_table);
+
+	return group;
+error:
+	if (group)
+		user_event_group_destroy(group);
+
+	return NULL;
+};
+
+static __always_inline
+void user_event_register_set(struct user_event *user)
+{
+	int i = user->index;
+
+	user->group->register_page_data[MAP_STATUS_BYTE(i)] |= MAP_STATUS_MASK(i);
+}
+
+static __always_inline
+void user_event_register_clear(struct user_event *user)
+{
+	int i = user->index;
+
+	user->group->register_page_data[MAP_STATUS_BYTE(i)] &= ~MAP_STATUS_MASK(i);
+}
+
+static __always_inline __must_check
+bool user_event_last_ref(struct user_event *user)
+{
+	return refcount_read(&user->refcnt) == 1;
+}
+
+static __always_inline __must_check
+size_t copy_nofault(void *addr, size_t bytes, struct iov_iter *i)
+{
+	size_t ret;
+
+	pagefault_disable();
+
+	ret = copy_from_iter_nocache(addr, bytes, i);
+
+	pagefault_enable();
+
+	return ret;
+}
+
+static struct list_head *user_event_get_fields(struct trace_event_call *call)
+{
+	struct user_event *user = (struct user_event *)call->data;
+
+	return &user->fields;
+}
+
+/*
+ * Parses a register command for user_events
+ * Format: event_name[:FLAG1[,FLAG2...]] [field1[;field2...]]
+ *
+ * Example event named 'test' with a 20 char 'msg' field with an unsigned int
+ * 'id' field after:
+ * test char[20] msg;unsigned int id
+ *
+ * NOTE: Offsets are from the user data perspective, they are not from the
+ * trace_entry/buffer perspective. We automatically add the common properties
+ * sizes to the offset for the user.
+ *
+ * Upon success user_event has its ref count increased by 1.
+ */
+static int user_event_parse_cmd(struct user_event_group *group,
+				char *raw_command, struct user_event **newuser)
+{
+	char *name = raw_command;
+	char *args = strpbrk(name, " ");
+	char *flags;
+
+	if (args)
+		*args++ = '\0';
+
+	flags = strpbrk(name, ":");
+
+	if (flags)
+		*flags++ = '\0';
+
+	return user_event_parse(group, name, args, flags, newuser);
+}
+
+static int user_field_array_size(const char *type)
+{
+	const char *start = strchr(type, '[');
+	char val[8];
+	char *bracket;
+	int size = 0;
+
+	if (start == NULL)
+		return -EINVAL;
+
+	if (strscpy(val, start + 1, sizeof(val)) <= 0)
+		return -EINVAL;
+
+	bracket = strchr(val, ']');
+
+	if (!bracket)
+		return -EINVAL;
+
+	*bracket = '\0';
+
+	if (kstrtouint(val, 0, &size))
+		return -EINVAL;
+
+	if (size > MAX_FIELD_ARRAY_SIZE)
+		return -EINVAL;
+
+	return size;
+}
+
+static int user_field_size(const char *type)
+{
+	/* long is not allowed from a user, since it's ambigious in size */
+	if (strcmp(type, "s64") == 0)
+		return sizeof(s64);
+	if (strcmp(type, "u64") == 0)
+		return sizeof(u64);
+	if (strcmp(type, "s32") == 0)
+		return sizeof(s32);
+	if (strcmp(type, "u32") == 0)
+		return sizeof(u32);
+	if (strcmp(type, "int") == 0)
+		return sizeof(int);
+	if (strcmp(type, "unsigned int") == 0)
+		return sizeof(unsigned int);
+	if (strcmp(type, "s16") == 0)
+		return sizeof(s16);
+	if (strcmp(type, "u16") == 0)
+		return sizeof(u16);
+	if (strcmp(type, "short") == 0)
+		return sizeof(short);
+	if (strcmp(type, "unsigned short") == 0)
+		return sizeof(unsigned short);
+	if (strcmp(type, "s8") == 0)
+		return sizeof(s8);
+	if (strcmp(type, "u8") == 0)
+		return sizeof(u8);
+	if (strcmp(type, "char") == 0)
+		return sizeof(char);
+	if (strcmp(type, "unsigned char") == 0)
+		return sizeof(unsigned char);
+	if (str_has_prefix(type, "char["))
+		return user_field_array_size(type);
+	if (str_has_prefix(type, "unsigned char["))
+		return user_field_array_size(type);
+	if (str_has_prefix(type, "__data_loc "))
+		return sizeof(u32);
+	if (str_has_prefix(type, "__rel_loc "))
+		return sizeof(u32);
+
+	/* Uknown basic type, error */
+	return -EINVAL;
+}
+
+static void user_event_destroy_validators(struct user_event *user)
+{
+	struct user_event_validator *validator, *next;
+	struct list_head *head = &user->validators;
+
+	list_for_each_entry_safe(validator, next, head, link) {
+		list_del(&validator->link);
+		kfree(validator);
+	}
+}
+
+static void user_event_destroy_fields(struct user_event *user)
+{
+	struct ftrace_event_field *field, *next;
+	struct list_head *head = &user->fields;
+
+	list_for_each_entry_safe(field, next, head, link) {
+		list_del(&field->link);
+		kfree(field);
+	}
+}
+
+static int user_event_add_field(struct user_event *user, const char *type,
+				const char *name, int offset, int size,
+				int is_signed, int filter_type)
+{
+	struct user_event_validator *validator;
+	struct ftrace_event_field *field;
+	int validator_flags = 0;
+
+	field = kmalloc(sizeof(*field), GFP_KERNEL);
+
+	if (!field)
+		return -ENOMEM;
+
+	if (str_has_prefix(type, "__data_loc "))
+		goto add_validator;
+
+	if (str_has_prefix(type, "__rel_loc ")) {
+		validator_flags |= VALIDATOR_REL;
+		goto add_validator;
+	}
+
+	goto add_field;
+
+add_validator:
+	if (strstr(type, "char") != NULL)
+		validator_flags |= VALIDATOR_ENSURE_NULL;
+
+	validator = kmalloc(sizeof(*validator), GFP_KERNEL);
+
+	if (!validator) {
+		kfree(field);
+		return -ENOMEM;
+	}
+
+	validator->flags = validator_flags;
+	validator->offset = offset;
+
+	/* Want sequential access when validating */
+	list_add_tail(&validator->link, &user->validators);
+
+add_field:
+	field->type = type;
+	field->name = name;
+	field->offset = offset;
+	field->size = size;
+	field->is_signed = is_signed;
+	field->filter_type = filter_type;
+
+	list_add(&field->link, &user->fields);
+
+	/*
+	 * Min size from user writes that are required, this does not include
+	 * the size of trace_entry (common fields).
+	 */
+	user->min_size = (offset + size) - sizeof(struct trace_entry);
+
+	return 0;
+}
+
+/*
+ * Parses the values of a field within the description
+ * Format: type name [size]
+ */
+static int user_event_parse_field(char *field, struct user_event *user,
+				  u32 *offset)
+{
+	char *part, *type, *name;
+	u32 depth = 0, saved_offset = *offset;
+	int len, size = -EINVAL;
+	bool is_struct = false;
+
+	field = skip_spaces(field);
+
+	if (*field == '\0')
+		return 0;
+
+	/* Handle types that have a space within */
+	len = str_has_prefix(field, "unsigned ");
+	if (len)
+		goto skip_next;
+
+	len = str_has_prefix(field, "struct ");
+	if (len) {
+		is_struct = true;
+		goto skip_next;
+	}
+
+	len = str_has_prefix(field, "__data_loc unsigned ");
+	if (len)
+		goto skip_next;
+
+	len = str_has_prefix(field, "__data_loc ");
+	if (len)
+		goto skip_next;
+
+	len = str_has_prefix(field, "__rel_loc unsigned ");
+	if (len)
+		goto skip_next;
+
+	len = str_has_prefix(field, "__rel_loc ");
+	if (len)
+		goto skip_next;
+
+	goto parse;
+skip_next:
+	type = field;
+	field = strpbrk(field + len, " ");
+
+	if (field == NULL)
+		return -EINVAL;
+
+	*field++ = '\0';
+	depth++;
+parse:
+	name = NULL;
+
+	while ((part = strsep(&field, " ")) != NULL) {
+		switch (depth++) {
+		case FIELD_DEPTH_TYPE:
+			type = part;
+			break;
+		case FIELD_DEPTH_NAME:
+			name = part;
+			break;
+		case FIELD_DEPTH_SIZE:
+			if (!is_struct)
+				return -EINVAL;
+
+			if (kstrtou32(part, 10, &size))
+				return -EINVAL;
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	if (depth < FIELD_DEPTH_SIZE || !name)
+		return -EINVAL;
+
+	if (depth == FIELD_DEPTH_SIZE)
+		size = user_field_size(type);
+
+	if (size == 0)
+		return -EINVAL;
+
+	if (size < 0)
+		return size;
+
+	*offset = saved_offset + size;
+
+	return user_event_add_field(user, type, name, saved_offset, size,
+				    type[0] != 'u', FILTER_OTHER);
+}
+
+static int user_event_parse_fields(struct user_event *user, char *args)
+{
+	char *field;
+	u32 offset = sizeof(struct trace_entry);
+	int ret = -EINVAL;
+
+	if (args == NULL)
+		return 0;
+
+	while ((field = strsep(&args, ";")) != NULL) {
+		ret = user_event_parse_field(field, user, &offset);
+
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static struct trace_event_fields user_event_fields_array[1];
+
+static const char *user_field_format(const char *type)
+{
+	if (strcmp(type, "s64") == 0)
+		return "%lld";
+	if (strcmp(type, "u64") == 0)
+		return "%llu";
+	if (strcmp(type, "s32") == 0)
+		return "%d";
+	if (strcmp(type, "u32") == 0)
+		return "%u";
+	if (strcmp(type, "int") == 0)
+		return "%d";
+	if (strcmp(type, "unsigned int") == 0)
+		return "%u";
+	if (strcmp(type, "s16") == 0)
+		return "%d";
+	if (strcmp(type, "u16") == 0)
+		return "%u";
+	if (strcmp(type, "short") == 0)
+		return "%d";
+	if (strcmp(type, "unsigned short") == 0)
+		return "%u";
+	if (strcmp(type, "s8") == 0)
+		return "%d";
+	if (strcmp(type, "u8") == 0)
+		return "%u";
+	if (strcmp(type, "char") == 0)
+		return "%d";
+	if (strcmp(type, "unsigned char") == 0)
+		return "%u";
+	if (strstr(type, "char[") != NULL)
+		return "%s";
+
+	/* Unknown, likely struct, allowed treat as 64-bit */
+	return "%llu";
+}
+
+static bool user_field_is_dyn_string(const char *type, const char **str_func)
+{
+	if (str_has_prefix(type, "__data_loc ")) {
+		*str_func = "__get_str";
+		goto check;
+	}
+
+	if (str_has_prefix(type, "__rel_loc ")) {
+		*str_func = "__get_rel_str";
+		goto check;
+	}
+
+	return false;
+check:
+	return strstr(type, "char") != NULL;
+}
+
+#define LEN_OR_ZERO (len ? len - pos : 0)
+static int user_dyn_field_set_string(int argc, const char **argv, int *iout,
+				     char *buf, int len, bool *colon)
+{
+	int pos = 0, i = *iout;
+
+	*colon = false;
+
+	for (; i < argc; ++i) {
+		if (i != *iout)
+			pos += snprintf(buf + pos, LEN_OR_ZERO, " ");
+
+		pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", argv[i]);
+
+		if (strchr(argv[i], ';')) {
+			++i;
+			*colon = true;
+			break;
+		}
+	}
+
+	/* Actual set, advance i */
+	if (len != 0)
+		*iout = i;
+
+	return pos + 1;
+}
+
+static int user_field_set_string(struct ftrace_event_field *field,
+				 char *buf, int len, bool colon)
+{
+	int pos = 0;
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", field->type);
+	pos += snprintf(buf + pos, LEN_OR_ZERO, " ");
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", field->name);
+
+	if (str_has_prefix(field->type, "struct "))
+		pos += snprintf(buf + pos, LEN_OR_ZERO, " %d", field->size);
+
+	if (colon)
+		pos += snprintf(buf + pos, LEN_OR_ZERO, ";");
+
+	return pos + 1;
+}
+
+static int user_event_set_print_fmt(struct user_event *user, char *buf, int len)
+{
+	struct ftrace_event_field *field, *next;
+	struct list_head *head = &user->fields;
+	int pos = 0, depth = 0;
+	const char *str_func;
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
+
+	list_for_each_entry_safe_reverse(field, next, head, link) {
+		if (depth != 0)
+			pos += snprintf(buf + pos, LEN_OR_ZERO, " ");
+
+		pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s",
+				field->name, user_field_format(field->type));
+
+		depth++;
+	}
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
+
+	list_for_each_entry_safe_reverse(field, next, head, link) {
+		if (user_field_is_dyn_string(field->type, &str_func))
+			pos += snprintf(buf + pos, LEN_OR_ZERO,
+					", %s(%s)", str_func, field->name);
+		else
+			pos += snprintf(buf + pos, LEN_OR_ZERO,
+					", REC->%s", field->name);
+	}
+
+	return pos + 1;
+}
+#undef LEN_OR_ZERO
+
+static int user_event_create_print_fmt(struct user_event *user)
+{
+	char *print_fmt;
+	int len;
+
+	len = user_event_set_print_fmt(user, NULL, 0);
+
+	print_fmt = kmalloc(len, GFP_KERNEL);
+
+	if (!print_fmt)
+		return -ENOMEM;
+
+	user_event_set_print_fmt(user, print_fmt, len);
+
+	user->call.print_fmt = print_fmt;
+
+	return 0;
+}
+
+static enum print_line_t user_event_print_trace(struct trace_iterator *iter,
+						int flags,
+						struct trace_event *event)
+{
+	/* Unsafe to try to decode user provided print_fmt, use hex */
+	trace_print_hex_dump_seq(&iter->seq, "", DUMP_PREFIX_OFFSET, 16,
+				 1, iter->ent, iter->ent_size, true);
+
+	return trace_handle_return(&iter->seq);
+}
+
+static struct trace_event_functions user_event_funcs = {
+	.trace = user_event_print_trace,
+};
+
+static int user_event_set_call_visible(struct user_event *user, bool visible)
+{
+	int ret;
+	const struct cred *old_cred;
+	struct cred *cred;
+
+	cred = prepare_creds();
+
+	if (!cred)
+		return -ENOMEM;
+
+	/*
+	 * While by default tracefs is locked down, systems can be configured
+	 * to allow user_event files to be less locked down. The extreme case
+	 * being "other" has read/write access to user_events_data/status.
+	 *
+	 * When not locked down, processes may not have permissions to
+	 * add/remove calls themselves to tracefs. We need to temporarily
+	 * switch to root file permission to allow for this scenario.
+	 */
+	cred->fsuid = GLOBAL_ROOT_UID;
+
+	old_cred = override_creds(cred);
+
+	if (visible)
+		ret = trace_add_event_call(&user->call);
+	else
+		ret = trace_remove_event_call(&user->call);
+
+	revert_creds(old_cred);
+	put_cred(cred);
+
+	return ret;
+}
+
+static int destroy_user_event(struct user_event *user)
+{
+	int ret = 0;
+
+	/* Must destroy fields before call removal */
+	user_event_destroy_fields(user);
+
+	ret = user_event_set_call_visible(user, false);
+
+	if (ret)
+		return ret;
+
+	dyn_event_remove(&user->devent);
+
+	user_event_register_clear(user);
+	clear_bit(user->index, user->group->page_bitmap);
+	hash_del(&user->node);
+
+	user_event_destroy_validators(user);
+	kfree(user->call.print_fmt);
+	kfree(EVENT_NAME(user));
+	kfree(user);
+
+	return ret;
+}
+
+static struct user_event *find_user_event(struct user_event_group *group,
+					  char *name, u32 *outkey)
+{
+	struct user_event *user;
+	u32 key = user_event_key(name);
+
+	*outkey = key;
+
+	hash_for_each_possible(group->register_table, user, node, key)
+		if (!strcmp(EVENT_NAME(user), name)) {
+			refcount_inc(&user->refcnt);
+			return user;
+		}
+
+	return NULL;
+}
+
+static int user_event_validate(struct user_event *user, void *data, int len)
+{
+	struct list_head *head = &user->validators;
+	struct user_event_validator *validator;
+	void *pos, *end = data + len;
+	u32 loc, offset, size;
+
+	list_for_each_entry(validator, head, link) {
+		pos = data + validator->offset;
+
+		/* Already done min_size check, no bounds check here */
+		loc = *(u32 *)pos;
+		offset = loc & 0xffff;
+		size = loc >> 16;
+
+		if (likely(validator->flags & VALIDATOR_REL))
+			pos += offset + sizeof(loc);
+		else
+			pos = data + offset;
+
+		pos += size;
+
+		if (unlikely(pos > end))
+			return -EFAULT;
+
+		if (likely(validator->flags & VALIDATOR_ENSURE_NULL))
+			if (unlikely(*(char *)(pos - 1) != '\0'))
+				return -EFAULT;
+	}
+
+	return 0;
+}
+
+/*
+ * Writes the user supplied payload out to a trace file.
+ */
+static void user_event_ftrace(struct user_event *user, struct iov_iter *i,
+			      void *tpdata, bool *faulted)
+{
+	struct trace_event_file *file;
+	struct trace_entry *entry;
+	struct trace_event_buffer event_buffer;
+	size_t size = sizeof(*entry) + i->count;
+
+	file = (struct trace_event_file *)tpdata;
+
+	if (!file ||
+	    !(file->flags & EVENT_FILE_FL_ENABLED) ||
+	    trace_trigger_soft_disabled(file))
+		return;
+
+	/* Allocates and fills trace_entry, + 1 of this is data payload */
+	entry = trace_event_buffer_reserve(&event_buffer, file, size);
+
+	if (unlikely(!entry))
+		return;
+
+	if (unlikely(!copy_nofault(entry + 1, i->count, i)))
+		goto discard;
+
+	if (!list_empty(&user->validators) &&
+	    unlikely(user_event_validate(user, entry, size)))
+		goto discard;
+
+	trace_event_buffer_commit(&event_buffer);
+
+	return;
+discard:
+	*faulted = true;
+	__trace_event_discard_commit(event_buffer.buffer,
+				     event_buffer.event);
+}
+
+#ifdef CONFIG_PERF_EVENTS
+/*
+ * Writes the user supplied payload out to perf ring buffer.
+ */
+static void user_event_perf(struct user_event *user, struct iov_iter *i,
+			    void *tpdata, bool *faulted)
+{
+	struct hlist_head *perf_head;
+
+	perf_head = this_cpu_ptr(user->call.perf_events);
+
+	if (perf_head && !hlist_empty(perf_head)) {
+		struct trace_entry *perf_entry;
+		struct pt_regs *regs;
+		size_t size = sizeof(*perf_entry) + i->count;
+		int context;
+
+		perf_entry = perf_trace_buf_alloc(ALIGN(size, 8),
+						  &regs, &context);
+
+		if (unlikely(!perf_entry))
+			return;
+
+		perf_fetch_caller_regs(regs);
+
+		if (unlikely(!copy_nofault(perf_entry + 1, i->count, i)))
+			goto discard;
+
+		if (!list_empty(&user->validators) &&
+		    unlikely(user_event_validate(user, perf_entry, size)))
+			goto discard;
+
+		perf_trace_buf_submit(perf_entry, size, context,
+				      user->call.event.type, 1, regs,
+				      perf_head, NULL);
+
+		return;
+discard:
+		*faulted = true;
+		perf_swevent_put_recursion_context(context);
+	}
+}
+#endif
+
+/*
+ * Update the register page that is shared between user processes.
+ */
+static void update_reg_page_for(struct user_event *user)
+{
+	struct tracepoint *tp = &user->tracepoint;
+	char status = 0;
+
+	if (atomic_read(&tp->key.enabled) > 0) {
+		struct tracepoint_func *probe_func_ptr;
+		user_event_func_t probe_func;
+
+		rcu_read_lock_sched();
+
+		probe_func_ptr = rcu_dereference_sched(tp->funcs);
+
+		if (probe_func_ptr) {
+			do {
+				probe_func = probe_func_ptr->func;
+
+				if (probe_func == user_event_ftrace)
+					status |= EVENT_STATUS_FTRACE;
+#ifdef CONFIG_PERF_EVENTS
+				else if (probe_func == user_event_perf)
+					status |= EVENT_STATUS_PERF;
+#endif
+				else
+					status |= EVENT_STATUS_OTHER;
+			} while ((++probe_func_ptr)->func);
+		}
+
+		rcu_read_unlock_sched();
+	}
+
+	if (status)
+		user_event_register_set(user);
+	else
+		user_event_register_clear(user);
+
+	user->status = status;
+}
+
+/*
+ * Register callback for our events from tracing sub-systems.
+ */
+static int user_event_reg(struct trace_event_call *call,
+			  enum trace_reg type,
+			  void *data)
+{
+	struct user_event *user = (struct user_event *)call->data;
+	int ret = 0;
+
+	if (!user)
+		return -ENOENT;
+
+	switch (type) {
+	case TRACE_REG_REGISTER:
+		ret = tracepoint_probe_register(call->tp,
+						call->class->probe,
+						data);
+		if (!ret)
+			goto inc;
+		break;
+
+	case TRACE_REG_UNREGISTER:
+		tracepoint_probe_unregister(call->tp,
+					    call->class->probe,
+					    data);
+		goto dec;
+
+#ifdef CONFIG_PERF_EVENTS
+	case TRACE_REG_PERF_REGISTER:
+		ret = tracepoint_probe_register(call->tp,
+						call->class->perf_probe,
+						data);
+		if (!ret)
+			goto inc;
+		break;
+
+	case TRACE_REG_PERF_UNREGISTER:
+		tracepoint_probe_unregister(call->tp,
+					    call->class->perf_probe,
+					    data);
+		goto dec;
+
+	case TRACE_REG_PERF_OPEN:
+	case TRACE_REG_PERF_CLOSE:
+	case TRACE_REG_PERF_ADD:
+	case TRACE_REG_PERF_DEL:
+		break;
+#endif
+	}
+
+	return ret;
+inc:
+	refcount_inc(&user->refcnt);
+	update_reg_page_for(user);
+	return 0;
+dec:
+	update_reg_page_for(user);
+	refcount_dec(&user->refcnt);
+	return 0;
+}
+
+static int user_event_create(const char *raw_command)
+{
+	struct user_event_group *group;
+	struct user_event *user;
+	char *name;
+	int ret;
+
+	if (!str_has_prefix(raw_command, USER_EVENTS_PREFIX))
+		return -ECANCELED;
+
+	raw_command += USER_EVENTS_PREFIX_LEN;
+	raw_command = skip_spaces(raw_command);
+
+	name = kstrdup(raw_command, GFP_KERNEL);
+
+	if (!name)
+		return -ENOMEM;
+
+	group = current_user_event_group();
+
+	if (!group) {
+		kfree(name);
+		return -ENOENT;
+	}
+
+	mutex_lock(&group->reg_mutex);
+
+	ret = user_event_parse_cmd(group, name, &user);
+
+	if (!ret)
+		refcount_dec(&user->refcnt);
+
+	mutex_unlock(&group->reg_mutex);
+
+	if (ret)
+		kfree(name);
+
+	return ret;
+}
+
+static int user_event_show(struct seq_file *m, struct dyn_event *ev)
+{
+	struct user_event *user = container_of(ev, struct user_event, devent);
+	struct ftrace_event_field *field, *next;
+	struct list_head *head;
+	int depth = 0;
+
+	seq_printf(m, "%s%s", USER_EVENTS_PREFIX, EVENT_NAME(user));
+
+	head = trace_get_fields(&user->call);
+
+	list_for_each_entry_safe_reverse(field, next, head, link) {
+		if (depth == 0)
+			seq_puts(m, " ");
+		else
+			seq_puts(m, "; ");
+
+		seq_printf(m, "%s %s", field->type, field->name);
+
+		if (str_has_prefix(field->type, "struct "))
+			seq_printf(m, " %d", field->size);
+
+		depth++;
+	}
+
+	seq_puts(m, "\n");
+
+	return 0;
+}
+
+static bool user_event_is_busy(struct dyn_event *ev)
+{
+	struct user_event *user = container_of(ev, struct user_event, devent);
+
+	return !user_event_last_ref(user);
+}
+
+static int user_event_free(struct dyn_event *ev)
+{
+	struct user_event *user = container_of(ev, struct user_event, devent);
+
+	if (!user_event_last_ref(user))
+		return -EBUSY;
+
+	return destroy_user_event(user);
+}
+
+static bool user_field_match(struct ftrace_event_field *field, int argc,
+			     const char **argv, int *iout)
+{
+	char *field_name = NULL, *dyn_field_name = NULL;
+	bool colon = false, match = false;
+	int dyn_len, len;
+
+	if (*iout >= argc)
+		return false;
+
+	dyn_len = user_dyn_field_set_string(argc, argv, iout, dyn_field_name,
+					    0, &colon);
+
+	len = user_field_set_string(field, field_name, 0, colon);
+
+	if (dyn_len != len)
+		return false;
+
+	dyn_field_name = kmalloc(dyn_len, GFP_KERNEL);
+	field_name = kmalloc(len, GFP_KERNEL);
+
+	if (!dyn_field_name || !field_name)
+		goto out;
+
+	user_dyn_field_set_string(argc, argv, iout, dyn_field_name,
+				  dyn_len, &colon);
+
+	user_field_set_string(field, field_name, len, colon);
+
+	match = strcmp(dyn_field_name, field_name) == 0;
+out:
+	kfree(dyn_field_name);
+	kfree(field_name);
+
+	return match;
+}
+
+static bool user_fields_match(struct user_event *user, int argc,
+			      const char **argv)
+{
+	struct ftrace_event_field *field, *next;
+	struct list_head *head = &user->fields;
+	int i = 0;
+
+	list_for_each_entry_safe_reverse(field, next, head, link)
+		if (!user_field_match(field, argc, argv, &i))
+			return false;
+
+	if (i != argc)
+		return false;
+
+	return true;
+}
+
+static bool user_event_match(const char *system, const char *event,
+			     int argc, const char **argv, struct dyn_event *ev)
+{
+	struct user_event *user = container_of(ev, struct user_event, devent);
+	bool match;
+
+	match = strcmp(EVENT_NAME(user), event) == 0 &&
+		(!system || strcmp(system, USER_EVENTS_SYSTEM) == 0);
+
+	if (match && argc > 0)
+		match = user_fields_match(user, argc, argv);
+
+	return match;
+}
+
+static struct dyn_event_operations user_event_dops = {
+	.create = user_event_create,
+	.show = user_event_show,
+	.is_busy = user_event_is_busy,
+	.free = user_event_free,
+	.match = user_event_match,
+};
+
+static int user_event_trace_register(struct user_event *user)
+{
+	int ret;
+
+	ret = register_trace_event(&user->call.event);
+
+	if (!ret)
+		return -ENODEV;
+
+	ret = user_event_set_call_visible(user, true);
+
+	if (ret)
+		unregister_trace_event(&user->call.event);
+
+	return ret;
+}
+
+/*
+ * Parses the event name, arguments and flags then registers if successful.
+ * The name buffer lifetime is owned by this method for success cases only.
+ * Upon success the returned user_event has its ref count increased by 1.
+ */
+static int user_event_parse(struct user_event_group *group, char *name,
+			    char *args, char *flags,
+			    struct user_event **newuser)
+{
+	int ret;
+	int index;
+	u32 key;
+	struct user_event *user;
+
+	/* Prevent dyn_event from racing */
+	mutex_lock(&event_mutex);
+	user = find_user_event(group, name, &key);
+	mutex_unlock(&event_mutex);
+
+	if (user) {
+		*newuser = user;
+		/*
+		 * Name is allocated by caller, free it since it already exists.
+		 * Caller only worries about failure cases for freeing.
+		 */
+		kfree(name);
+		return 0;
+	}
+
+	index = find_first_zero_bit(group->page_bitmap, MAX_EVENTS);
+
+	if (index == MAX_EVENTS)
+		return -EMFILE;
+
+	user = kzalloc(sizeof(*user), GFP_KERNEL);
+
+	if (!user)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&user->class.fields);
+	INIT_LIST_HEAD(&user->fields);
+	INIT_LIST_HEAD(&user->validators);
+
+	user->group = group;
+	user->tracepoint.name = name;
+
+	ret = user_event_parse_fields(user, args);
+
+	if (ret)
+		goto put_user;
+
+	ret = user_event_create_print_fmt(user);
+
+	if (ret)
+		goto put_user;
+
+	user->call.data = user;
+	user->call.class = &user->class;
+	user->call.name = name;
+	user->call.flags = TRACE_EVENT_FL_TRACEPOINT;
+	user->call.tp = &user->tracepoint;
+	user->call.event.funcs = &user_event_funcs;
+	user->class.system = group->system_name;
+
+	user->class.fields_array = user_event_fields_array;
+	user->class.get_fields = user_event_get_fields;
+	user->class.reg = user_event_reg;
+	user->class.probe = user_event_ftrace;
+#ifdef CONFIG_PERF_EVENTS
+	user->class.perf_probe = user_event_perf;
+#endif
+
+	mutex_lock(&event_mutex);
+
+	ret = user_event_trace_register(user);
+
+	if (ret)
+		goto put_user_lock;
+
+	user->index = index;
+
+	/* Ensure we track self ref and caller ref (2) */
+	refcount_set(&user->refcnt, 2);
+
+	dyn_event_init(&user->devent, &user_event_dops);
+	dyn_event_add(&user->devent, &user->call);
+	set_bit(user->index, group->page_bitmap);
+	hash_add(group->register_table, &user->node, key);
+
+	mutex_unlock(&event_mutex);
+
+	*newuser = user;
+	return 0;
+put_user_lock:
+	mutex_unlock(&event_mutex);
+put_user:
+	user_event_destroy_fields(user);
+	user_event_destroy_validators(user);
+	kfree(user->call.print_fmt);
+	kfree(user);
+	return ret;
+}
+
+/*
+ * Deletes a previously created event if it is no longer being used.
+ */
+static int delete_user_event(struct user_event_group *group, char *name)
+{
+	u32 key;
+	struct user_event *user = find_user_event(group, name, &key);
+
+	if (!user)
+		return -ENOENT;
+
+	refcount_dec(&user->refcnt);
+
+	if (!user_event_last_ref(user))
+		return -EBUSY;
+
+	return destroy_user_event(user);
+}
+
+/*
+ * Validates the user payload and writes via iterator.
+ */
+static ssize_t user_events_write_core(struct file *file, struct iov_iter *i)
+{
+	struct user_event_file_info *info = file->private_data;
+	struct user_event_refs *refs;
+	struct user_event *user = NULL;
+	struct tracepoint *tp;
+	ssize_t ret = i->count;
+	int idx;
+
+	if (unlikely(copy_from_iter(&idx, sizeof(idx), i) != sizeof(idx)))
+		return -EFAULT;
+
+	if (idx < 0)
+		return -EINVAL;
+
+	rcu_read_lock_sched();
+
+	refs = rcu_dereference_sched(info->refs);
+
+	/*
+	 * The refs->events array is protected by RCU, and new items may be
+	 * added. But the user retrieved from indexing into the events array
+	 * shall be immutable while the file is opened.
+	 */
+	if (likely(refs && idx < refs->count))
+		user = refs->events[idx];
+
+	rcu_read_unlock_sched();
+
+	if (unlikely(user == NULL))
+		return -ENOENT;
+
+	if (unlikely(i->count < user->min_size))
+		return -EINVAL;
+
+	tp = &user->tracepoint;
+
+	/*
+	 * It's possible key.enabled disables after this check, however
+	 * we don't mind if a few events are included in this condition.
+	 */
+	if (likely(atomic_read(&tp->key.enabled) > 0)) {
+		struct tracepoint_func *probe_func_ptr;
+		user_event_func_t probe_func;
+		struct iov_iter copy;
+		void *tpdata;
+		bool faulted;
+
+		if (unlikely(fault_in_iov_iter_readable(i, i->count)))
+			return -EFAULT;
+
+		faulted = false;
+
+		rcu_read_lock_sched();
+
+		probe_func_ptr = rcu_dereference_sched(tp->funcs);
+
+		if (probe_func_ptr) {
+			do {
+				copy = *i;
+				probe_func = probe_func_ptr->func;
+				tpdata = probe_func_ptr->data;
+				probe_func(user, &copy, tpdata, &faulted);
+			} while ((++probe_func_ptr)->func);
+		}
+
+		rcu_read_unlock_sched();
+
+		if (unlikely(faulted))
+			return -EFAULT;
+	} else
+		return -EBADF;
+
+	return ret;
+}
+
+static int user_events_open(struct inode *node, struct file *file)
+{
+	struct user_event_group *group;
+	struct user_event_file_info *info;
+
+	group = current_user_event_group();
+
+	if (!group)
+		return -ENOENT;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+
+	if (!info)
+		return -ENOMEM;
+
+	info->group = group;
+
+	file->private_data = info;
+
+	return 0;
+}
+
+static ssize_t user_events_write(struct file *file, const char __user *ubuf,
+				 size_t count, loff_t *ppos)
+{
+	struct iovec iov;
+	struct iov_iter i;
+
+	if (unlikely(*ppos != 0))
+		return -EFAULT;
+
+	if (unlikely(import_single_range(ITER_SOURCE, (char __user *)ubuf,
+					 count, &iov, &i)))
+		return -EFAULT;
+
+	return user_events_write_core(file, &i);
+}
+
+static ssize_t user_events_write_iter(struct kiocb *kp, struct iov_iter *i)
+{
+	return user_events_write_core(kp->ki_filp, i);
+}
+
+static int user_events_ref_add(struct user_event_file_info *info,
+			       struct user_event *user)
+{
+	struct user_event_group *group = info->group;
+	struct user_event_refs *refs, *new_refs;
+	int i, size, count = 0;
+
+	refs = rcu_dereference_protected(info->refs,
+					 lockdep_is_held(&group->reg_mutex));
+
+	if (refs) {
+		count = refs->count;
+
+		for (i = 0; i < count; ++i)
+			if (refs->events[i] == user)
+				return i;
+	}
+
+	size = struct_size(refs, events, count + 1);
+
+	new_refs = kzalloc(size, GFP_KERNEL);
+
+	if (!new_refs)
+		return -ENOMEM;
+
+	new_refs->count = count + 1;
+
+	for (i = 0; i < count; ++i)
+		new_refs->events[i] = refs->events[i];
+
+	new_refs->events[i] = user;
+
+	refcount_inc(&user->refcnt);
+
+	rcu_assign_pointer(info->refs, new_refs);
+
+	if (refs)
+		kfree_rcu(refs, rcu);
+
+	return i;
+}
+
+static long user_reg_get(struct user_reg __user *ureg, struct user_reg *kreg)
+{
+	u32 size;
+	long ret;
+
+	ret = get_user(size, &ureg->size);
+
+	if (ret)
+		return ret;
+
+	if (size > PAGE_SIZE)
+		return -E2BIG;
+
+	if (size < offsetofend(struct user_reg, write_index))
+		return -EINVAL;
+
+	ret = copy_struct_from_user(kreg, sizeof(*kreg), ureg, size);
+
+	if (ret)
+		return ret;
+
+	kreg->size = size;
+
+	return 0;
+}
+
+/*
+ * Registers a user_event on behalf of a user process.
+ */
+static long user_events_ioctl_reg(struct user_event_file_info *info,
+				  unsigned long uarg)
+{
+	struct user_reg __user *ureg = (struct user_reg __user *)uarg;
+	struct user_reg reg;
+	struct user_event *user;
+	char *name;
+	long ret;
+
+	ret = user_reg_get(ureg, &reg);
+
+	if (ret)
+		return ret;
+
+	name = strndup_user((const char __user *)(uintptr_t)reg.name_args,
+			    MAX_EVENT_DESC);
+
+	if (IS_ERR(name)) {
+		ret = PTR_ERR(name);
+		return ret;
+	}
+
+	ret = user_event_parse_cmd(info->group, name, &user);
+
+	if (ret) {
+		kfree(name);
+		return ret;
+	}
+
+	ret = user_events_ref_add(info, user);
+
+	/* No longer need parse ref, ref_add either worked or not */
+	refcount_dec(&user->refcnt);
+
+	/* Positive number is index and valid */
+	if (ret < 0)
+		return ret;
+
+	put_user((u32)ret, &ureg->write_index);
+	put_user(user->index, &ureg->status_bit);
+
+	return 0;
+}
+
+/*
+ * Deletes a user_event on behalf of a user process.
+ */
+static long user_events_ioctl_del(struct user_event_file_info *info,
+				  unsigned long uarg)
+{
+	void __user *ubuf = (void __user *)uarg;
+	char *name;
+	long ret;
+
+	name = strndup_user(ubuf, MAX_EVENT_DESC);
+
+	if (IS_ERR(name))
+		return PTR_ERR(name);
+
+	/* event_mutex prevents dyn_event from racing */
+	mutex_lock(&event_mutex);
+	ret = delete_user_event(info->group, name);
+	mutex_unlock(&event_mutex);
+
+	kfree(name);
+
+	return ret;
+}
+
+/*
+ * Handles the ioctl from user mode to register or alter operations.
+ */
+static long user_events_ioctl(struct file *file, unsigned int cmd,
+			      unsigned long uarg)
+{
+	struct user_event_file_info *info = file->private_data;
+	struct user_event_group *group = info->group;
+	long ret = -ENOTTY;
+
+	switch (cmd) {
+	case DIAG_IOCSREG:
+		mutex_lock(&group->reg_mutex);
+		ret = user_events_ioctl_reg(info, uarg);
+		mutex_unlock(&group->reg_mutex);
+		break;
+
+	case DIAG_IOCSDEL:
+		mutex_lock(&group->reg_mutex);
+		ret = user_events_ioctl_del(info, uarg);
+		mutex_unlock(&group->reg_mutex);
+		break;
+	}
+
+	return ret;
+}
+
+/*
+ * Handles the final close of the file from user mode.
+ */
+static int user_events_release(struct inode *node, struct file *file)
+{
+	struct user_event_file_info *info = file->private_data;
+	struct user_event_group *group;
+	struct user_event_refs *refs;
+	struct user_event *user;
+	int i;
+
+	if (!info)
+		return -EINVAL;
+
+	group = info->group;
+
+	/*
+	 * Ensure refs cannot change under any situation by taking the
+	 * register mutex during the final freeing of the references.
+	 */
+	mutex_lock(&group->reg_mutex);
+
+	refs = info->refs;
+
+	if (!refs)
+		goto out;
+
+	/*
+	 * The lifetime of refs has reached an end, it's tied to this file.
+	 * The underlying user_events are ref counted, and cannot be freed.
+	 * After this decrement, the user_events may be freed elsewhere.
+	 */
+	for (i = 0; i < refs->count; ++i) {
+		user = refs->events[i];
+
+		if (user)
+			refcount_dec(&user->refcnt);
+	}
+out:
+	file->private_data = NULL;
+
+	mutex_unlock(&group->reg_mutex);
+
+	kfree(refs);
+	kfree(info);
+
+	return 0;
+}
+
+static const struct file_operations user_data_fops = {
+	.open = user_events_open,
+	.write = user_events_write,
+	.write_iter = user_events_write_iter,
+	.unlocked_ioctl	= user_events_ioctl,
+	.release = user_events_release,
+};
+
+static struct user_event_group *user_status_group(struct file *file)
+{
+	struct seq_file *m = file->private_data;
+
+	if (!m)
+		return NULL;
+
+	return m->private;
+}
+
+/*
+ * Maps the shared page into the user process for checking if event is enabled.
+ */
+static int user_status_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	char *pages;
+	struct user_event_group *group = user_status_group(file);
+	unsigned long size = vma->vm_end - vma->vm_start;
+
+	if (size != MAX_BYTES)
+		return -EINVAL;
+
+	if (!group)
+		return -EINVAL;
+
+	pages = group->register_page_data;
+
+	return remap_pfn_range(vma, vma->vm_start,
+			       virt_to_phys(pages) >> PAGE_SHIFT,
+			       size, vm_get_page_prot(VM_READ));
+}
+
+static void *user_seq_start(struct seq_file *m, loff_t *pos)
+{
+	if (*pos)
+		return NULL;
+
+	return (void *)1;
+}
+
+static void *user_seq_next(struct seq_file *m, void *p, loff_t *pos)
+{
+	++*pos;
+	return NULL;
+}
+
+static void user_seq_stop(struct seq_file *m, void *p)
+{
+}
+
+static int user_seq_show(struct seq_file *m, void *p)
+{
+	struct user_event_group *group = m->private;
+	struct user_event *user;
+	char status;
+	int i, active = 0, busy = 0, flags;
+
+	if (!group)
+		return -EINVAL;
+
+	mutex_lock(&group->reg_mutex);
+
+	hash_for_each(group->register_table, i, user, node) {
+		status = user->status;
+		flags = user->flags;
+
+		seq_printf(m, "%d:%s", user->index, EVENT_NAME(user));
+
+		if (flags != 0 || status != 0)
+			seq_puts(m, " #");
+
+		if (status != 0) {
+			seq_puts(m, " Used by");
+			if (status & EVENT_STATUS_FTRACE)
+				seq_puts(m, " ftrace");
+			if (status & EVENT_STATUS_PERF)
+				seq_puts(m, " perf");
+			if (status & EVENT_STATUS_OTHER)
+				seq_puts(m, " other");
+			busy++;
+		}
+
+		seq_puts(m, "\n");
+		active++;
+	}
+
+	mutex_unlock(&group->reg_mutex);
+
+	seq_puts(m, "\n");
+	seq_printf(m, "Active: %d\n", active);
+	seq_printf(m, "Busy: %d\n", busy);
+	seq_printf(m, "Max: %ld\n", MAX_EVENTS);
+
+	return 0;
+}
+
+static const struct seq_operations user_seq_ops = {
+	.start = user_seq_start,
+	.next  = user_seq_next,
+	.stop  = user_seq_stop,
+	.show  = user_seq_show,
+};
+
+static int user_status_open(struct inode *node, struct file *file)
+{
+	struct user_event_group *group;
+	int ret;
+
+	group = current_user_event_group();
+
+	if (!group)
+		return -ENOENT;
+
+	ret = seq_open(file, &user_seq_ops);
+
+	if (!ret) {
+		/* Chain group to seq_file */
+		struct seq_file *m = file->private_data;
+
+		m->private = group;
+	}
+
+	return ret;
+}
+
+static const struct file_operations user_status_fops = {
+	.open = user_status_open,
+	.mmap = user_status_mmap,
+	.read = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release,
+};
+
+/*
+ * Creates a set of tracefs files to allow user mode interactions.
+ */
+static int create_user_tracefs(void)
+{
+	struct dentry *edata, *emmap;
+
+	edata = tracefs_create_file("user_events_data", TRACE_MODE_WRITE,
+				    NULL, NULL, &user_data_fops);
+
+	if (!edata) {
+		pr_warn("Could not create tracefs 'user_events_data' entry\n");
+		goto err;
+	}
+
+	/* mmap with MAP_SHARED requires writable fd */
+	emmap = tracefs_create_file("user_events_status", TRACE_MODE_WRITE,
+				    NULL, NULL, &user_status_fops);
+
+	if (!emmap) {
+		tracefs_remove(edata);
+		pr_warn("Could not create tracefs 'user_events_mmap' entry\n");
+		goto err;
+	}
+
+	return 0;
+err:
+	return -ENODEV;
+}
+
+static int __init trace_events_user_init(void)
+{
+	int ret;
+
+	init_group = user_event_group_create(&init_user_ns);
+
+	if (!init_group)
+		return -ENOMEM;
+
+	ret = create_user_tracefs();
+
+	if (ret) {
+		pr_warn("user_events could not register with tracefs\n");
+		user_event_group_destroy(init_group);
+		init_group = NULL;
+		return ret;
+	}
+
+	if (dyn_event_register(&user_event_dops))
+		pr_warn("user_events could not register with dyn_events\n");
+
+	return 0;
+}
+
+fs_initcall(trace_events_user_init);
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
new file mode 100644
index 000000000..58f394608
--- /dev/null
+++ b/kernel/trace/trace_export.c
@@ -0,0 +1,192 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_export.c - export basic ftrace utilities to user space
+ *
+ * Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
+ */
+#include <linux/stringify.h>
+#include <linux/kallsyms.h>
+#include <linux/seq_file.h>
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include "trace_output.h"
+
+/* Stub function for events with triggers */
+static int ftrace_event_register(struct trace_event_call *call,
+				 enum trace_reg type, void *data)
+{
+	return 0;
+}
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM	ftrace
+
+/*
+ * The FTRACE_ENTRY_REG macro allows ftrace entry to define register
+ * function and thus become accessible via perf.
+ */
+#undef FTRACE_ENTRY_REG
+#define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print, regfn) \
+	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
+
+/* not needed for this file */
+#undef __field_struct
+#define __field_struct(type, item)
+
+#undef __field
+#define __field(type, item)				type item;
+
+#undef __field_fn
+#define __field_fn(type, item)				type item;
+
+#undef __field_desc
+#define __field_desc(type, container, item)		type item;
+
+#undef __field_packed
+#define __field_packed(type, container, item)		type item;
+
+#undef __array
+#define __array(type, item, size)			type item[size];
+
+#undef __array_desc
+#define __array_desc(type, container, item, size)	type item[size];
+
+#undef __dynamic_array
+#define __dynamic_array(type, item)			type item[];
+
+#undef F_STRUCT
+#define F_STRUCT(args...)				args
+
+#undef F_printk
+#define F_printk(fmt, args...) fmt, args
+
+#undef FTRACE_ENTRY
+#define FTRACE_ENTRY(name, struct_name, id, tstruct, print)		\
+struct ____ftrace_##name {						\
+	tstruct								\
+};									\
+static void __always_unused ____ftrace_check_##name(void)		\
+{									\
+	struct ____ftrace_##name *__entry = NULL;			\
+									\
+	/* force compile-time check on F_printk() */			\
+	printk(print);							\
+}
+
+#undef FTRACE_ENTRY_DUP
+#define FTRACE_ENTRY_DUP(name, struct_name, id, tstruct, print)		\
+	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
+
+#include "trace_entries.h"
+
+#undef __field_ext
+#define __field_ext(_type, _item, _filter_type) {			\
+	.type = #_type, .name = #_item,					\
+	.size = sizeof(_type), .align = __alignof__(_type),		\
+	is_signed_type(_type), .filter_type = _filter_type },
+
+
+#undef __field_ext_packed
+#define __field_ext_packed(_type, _item, _filter_type) {	\
+	.type = #_type, .name = #_item,				\
+	.size = sizeof(_type), .align = 1,			\
+	is_signed_type(_type), .filter_type = _filter_type },
+
+#undef __field
+#define __field(_type, _item) __field_ext(_type, _item, FILTER_OTHER)
+
+#undef __field_fn
+#define __field_fn(_type, _item) __field_ext(_type, _item, FILTER_TRACE_FN)
+
+#undef __field_desc
+#define __field_desc(_type, _container, _item) __field_ext(_type, _item, FILTER_OTHER)
+
+#undef __field_packed
+#define __field_packed(_type, _container, _item) __field_ext_packed(_type, _item, FILTER_OTHER)
+
+#undef __array
+#define __array(_type, _item, _len) {					\
+	.type = #_type"["__stringify(_len)"]", .name = #_item,		\
+	.size = sizeof(_type[_len]), .align = __alignof__(_type),	\
+	is_signed_type(_type), .filter_type = FILTER_OTHER,			\
+	.len = _len },
+
+#undef __array_desc
+#define __array_desc(_type, _container, _item, _len) __array(_type, _item, _len)
+
+#undef __dynamic_array
+#define __dynamic_array(_type, _item) {					\
+	.type = #_type "[]", .name = #_item,				\
+	.size = 0, .align = __alignof__(_type),				\
+	is_signed_type(_type), .filter_type = FILTER_OTHER },
+
+#undef FTRACE_ENTRY
+#define FTRACE_ENTRY(name, struct_name, id, tstruct, print)		\
+static struct trace_event_fields ftrace_event_fields_##name[] = {	\
+	tstruct								\
+	{} };
+
+#include "trace_entries.h"
+
+#undef __entry
+#define __entry REC
+
+#undef __field
+#define __field(type, item)
+
+#undef __field_fn
+#define __field_fn(type, item)
+
+#undef __field_desc
+#define __field_desc(type, container, item)
+
+#undef __field_packed
+#define __field_packed(type, container, item)
+
+#undef __array
+#define __array(type, item, len)
+
+#undef __array_desc
+#define __array_desc(type, container, item, len)
+
+#undef __dynamic_array
+#define __dynamic_array(type, item)
+
+#undef F_printk
+#define F_printk(fmt, args...) __stringify(fmt) ", "  __stringify(args)
+
+#undef FTRACE_ENTRY_REG
+#define FTRACE_ENTRY_REG(call, struct_name, etype, tstruct, print, regfn) \
+static struct trace_event_class __refdata event_class_ftrace_##call = {	\
+	.system			= __stringify(TRACE_SYSTEM),		\
+	.fields_array		= ftrace_event_fields_##call,		\
+	.fields			= LIST_HEAD_INIT(event_class_ftrace_##call.fields),\
+	.reg			= regfn,				\
+};									\
+									\
+struct trace_event_call __used event_##call = {				\
+	.class			= &event_class_ftrace_##call,		\
+	{								\
+		.name			= #call,			\
+	},								\
+	.event.type		= etype,				\
+	.print_fmt		= print,				\
+	.flags			= TRACE_EVENT_FL_IGNORE_ENABLE,		\
+};									\
+static struct trace_event_call __used						\
+__section("_ftrace_events") *__event_##call = &event_##call;
+
+#undef FTRACE_ENTRY
+#define FTRACE_ENTRY(call, struct_name, etype, tstruct, print)		\
+	FTRACE_ENTRY_REG(call, struct_name, etype,			\
+			 PARAMS(tstruct), PARAMS(print), NULL)
+
+bool ftrace_event_is_function(struct trace_event_call *call)
+{
+	return call == &event_function;
+}
+
+#include "trace_entries.h"
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
new file mode 100644
index 000000000..9f1bfbe10
--- /dev/null
+++ b/kernel/trace/trace_functions.c
@@ -0,0 +1,974 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ring buffer based function tracer
+ *
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ *
+ * Based on code from the latency_tracer, that is:
+ *
+ *  Copyright (C) 2004-2006 Ingo Molnar
+ *  Copyright (C) 2004 Nadia Yvette Chambers
+ */
+#include <linux/ring_buffer.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+
+#include "trace.h"
+
+static void tracing_start_function_trace(struct trace_array *tr);
+static void tracing_stop_function_trace(struct trace_array *tr);
+static void
+function_trace_call(unsigned long ip, unsigned long parent_ip,
+		    struct ftrace_ops *op, struct ftrace_regs *fregs);
+static void
+function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
+			  struct ftrace_ops *op, struct ftrace_regs *fregs);
+static void
+function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
+			       struct ftrace_ops *op, struct ftrace_regs *fregs);
+static void
+function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
+				     struct ftrace_ops *op,
+				     struct ftrace_regs *fregs);
+static struct tracer_flags func_flags;
+
+/* Our option */
+enum {
+
+	TRACE_FUNC_NO_OPTS		= 0x0, /* No flags set. */
+	TRACE_FUNC_OPT_STACK		= 0x1,
+	TRACE_FUNC_OPT_NO_REPEATS	= 0x2,
+
+	/* Update this to next highest bit. */
+	TRACE_FUNC_OPT_HIGHEST_BIT	= 0x4
+};
+
+#define TRACE_FUNC_OPT_MASK	(TRACE_FUNC_OPT_HIGHEST_BIT - 1)
+
+int ftrace_allocate_ftrace_ops(struct trace_array *tr)
+{
+	struct ftrace_ops *ops;
+
+	/* The top level array uses the "global_ops" */
+	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
+		return 0;
+
+	ops = kzalloc(sizeof(*ops), GFP_KERNEL);
+	if (!ops)
+		return -ENOMEM;
+
+	/* Currently only the non stack version is supported */
+	ops->func = function_trace_call;
+	ops->flags = FTRACE_OPS_FL_PID;
+
+	tr->ops = ops;
+	ops->private = tr;
+
+	return 0;
+}
+
+void ftrace_free_ftrace_ops(struct trace_array *tr)
+{
+	kfree(tr->ops);
+	tr->ops = NULL;
+}
+
+int ftrace_create_function_files(struct trace_array *tr,
+				 struct dentry *parent)
+{
+	/*
+	 * The top level array uses the "global_ops", and the files are
+	 * created on boot up.
+	 */
+	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
+		return 0;
+
+	if (!tr->ops)
+		return -EINVAL;
+
+	ftrace_create_filter_files(tr->ops, parent);
+
+	return 0;
+}
+
+void ftrace_destroy_function_files(struct trace_array *tr)
+{
+	ftrace_destroy_filter_files(tr->ops);
+	ftrace_free_ftrace_ops(tr);
+}
+
+static ftrace_func_t select_trace_function(u32 flags_val)
+{
+	switch (flags_val & TRACE_FUNC_OPT_MASK) {
+	case TRACE_FUNC_NO_OPTS:
+		return function_trace_call;
+	case TRACE_FUNC_OPT_STACK:
+		return function_stack_trace_call;
+	case TRACE_FUNC_OPT_NO_REPEATS:
+		return function_no_repeats_trace_call;
+	case TRACE_FUNC_OPT_STACK | TRACE_FUNC_OPT_NO_REPEATS:
+		return function_stack_no_repeats_trace_call;
+	default:
+		return NULL;
+	}
+}
+
+static bool handle_func_repeats(struct trace_array *tr, u32 flags_val)
+{
+	if (!tr->last_func_repeats &&
+	    (flags_val & TRACE_FUNC_OPT_NO_REPEATS)) {
+		tr->last_func_repeats = alloc_percpu(struct trace_func_repeats);
+		if (!tr->last_func_repeats)
+			return false;
+	}
+
+	return true;
+}
+
+static int function_trace_init(struct trace_array *tr)
+{
+	ftrace_func_t func;
+	/*
+	 * Instance trace_arrays get their ops allocated
+	 * at instance creation. Unless it failed
+	 * the allocation.
+	 */
+	if (!tr->ops)
+		return -ENOMEM;
+
+	func = select_trace_function(func_flags.val);
+	if (!func)
+		return -EINVAL;
+
+	if (!handle_func_repeats(tr, func_flags.val))
+		return -ENOMEM;
+
+	ftrace_init_array_ops(tr, func);
+
+	tr->array_buffer.cpu = raw_smp_processor_id();
+
+	tracing_start_cmdline_record();
+	tracing_start_function_trace(tr);
+	return 0;
+}
+
+static void function_trace_reset(struct trace_array *tr)
+{
+	tracing_stop_function_trace(tr);
+	tracing_stop_cmdline_record();
+	ftrace_reset_array_ops(tr);
+}
+
+static void function_trace_start(struct trace_array *tr)
+{
+	tracing_reset_online_cpus(&tr->array_buffer);
+}
+
+static void
+function_trace_call(unsigned long ip, unsigned long parent_ip,
+		    struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	struct trace_array *tr = op->private;
+	struct trace_array_cpu *data;
+	unsigned int trace_ctx;
+	int bit;
+	int cpu;
+
+	if (unlikely(!tr->function_enabled))
+		return;
+
+	bit = ftrace_test_recursion_trylock(ip, parent_ip);
+	if (bit < 0)
+		return;
+
+	trace_ctx = tracing_gen_ctx();
+
+	cpu = smp_processor_id();
+	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+	if (!atomic_read(&data->disabled))
+		trace_function(tr, ip, parent_ip, trace_ctx);
+
+	ftrace_test_recursion_unlock(bit);
+}
+
+#ifdef CONFIG_UNWINDER_ORC
+/*
+ * Skip 2:
+ *
+ *   function_stack_trace_call()
+ *   ftrace_call()
+ */
+#define STACK_SKIP 2
+#else
+/*
+ * Skip 3:
+ *   __trace_stack()
+ *   function_stack_trace_call()
+ *   ftrace_call()
+ */
+#define STACK_SKIP 3
+#endif
+
+static void
+function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
+			  struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	struct trace_array *tr = op->private;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	long disabled;
+	int cpu;
+	unsigned int trace_ctx;
+
+	if (unlikely(!tr->function_enabled))
+		return;
+
+	/*
+	 * Need to use raw, since this must be called before the
+	 * recursive protection is performed.
+	 */
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+	disabled = atomic_inc_return(&data->disabled);
+
+	if (likely(disabled == 1)) {
+		trace_ctx = tracing_gen_ctx_flags(flags);
+		trace_function(tr, ip, parent_ip, trace_ctx);
+		__trace_stack(tr, trace_ctx, STACK_SKIP);
+	}
+
+	atomic_dec(&data->disabled);
+	local_irq_restore(flags);
+}
+
+static inline bool is_repeat_check(struct trace_array *tr,
+				   struct trace_func_repeats *last_info,
+				   unsigned long ip, unsigned long parent_ip)
+{
+	if (last_info->ip == ip &&
+	    last_info->parent_ip == parent_ip &&
+	    last_info->count < U16_MAX) {
+		last_info->ts_last_call =
+			ring_buffer_time_stamp(tr->array_buffer.buffer);
+		last_info->count++;
+		return true;
+	}
+
+	return false;
+}
+
+static inline void process_repeats(struct trace_array *tr,
+				   unsigned long ip, unsigned long parent_ip,
+				   struct trace_func_repeats *last_info,
+				   unsigned int trace_ctx)
+{
+	if (last_info->count) {
+		trace_last_func_repeats(tr, last_info, trace_ctx);
+		last_info->count = 0;
+	}
+
+	last_info->ip = ip;
+	last_info->parent_ip = parent_ip;
+}
+
+static void
+function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
+			       struct ftrace_ops *op,
+			       struct ftrace_regs *fregs)
+{
+	struct trace_func_repeats *last_info;
+	struct trace_array *tr = op->private;
+	struct trace_array_cpu *data;
+	unsigned int trace_ctx;
+	unsigned long flags;
+	int bit;
+	int cpu;
+
+	if (unlikely(!tr->function_enabled))
+		return;
+
+	bit = ftrace_test_recursion_trylock(ip, parent_ip);
+	if (bit < 0)
+		return;
+
+	cpu = smp_processor_id();
+	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+	if (atomic_read(&data->disabled))
+		goto out;
+
+	/*
+	 * An interrupt may happen at any place here. But as far as I can see,
+	 * the only damage that this can cause is to mess up the repetition
+	 * counter without valuable data being lost.
+	 * TODO: think about a solution that is better than just hoping to be
+	 * lucky.
+	 */
+	last_info = per_cpu_ptr(tr->last_func_repeats, cpu);
+	if (is_repeat_check(tr, last_info, ip, parent_ip))
+		goto out;
+
+	local_save_flags(flags);
+	trace_ctx = tracing_gen_ctx_flags(flags);
+	process_repeats(tr, ip, parent_ip, last_info, trace_ctx);
+
+	trace_function(tr, ip, parent_ip, trace_ctx);
+
+out:
+	ftrace_test_recursion_unlock(bit);
+}
+
+static void
+function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
+				     struct ftrace_ops *op,
+				     struct ftrace_regs *fregs)
+{
+	struct trace_func_repeats *last_info;
+	struct trace_array *tr = op->private;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	long disabled;
+	int cpu;
+	unsigned int trace_ctx;
+
+	if (unlikely(!tr->function_enabled))
+		return;
+
+	/*
+	 * Need to use raw, since this must be called before the
+	 * recursive protection is performed.
+	 */
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+	disabled = atomic_inc_return(&data->disabled);
+
+	if (likely(disabled == 1)) {
+		last_info = per_cpu_ptr(tr->last_func_repeats, cpu);
+		if (is_repeat_check(tr, last_info, ip, parent_ip))
+			goto out;
+
+		trace_ctx = tracing_gen_ctx_flags(flags);
+		process_repeats(tr, ip, parent_ip, last_info, trace_ctx);
+
+		trace_function(tr, ip, parent_ip, trace_ctx);
+		__trace_stack(tr, trace_ctx, STACK_SKIP);
+	}
+
+ out:
+	atomic_dec(&data->disabled);
+	local_irq_restore(flags);
+}
+
+static struct tracer_opt func_opts[] = {
+#ifdef CONFIG_STACKTRACE
+	{ TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
+#endif
+	{ TRACER_OPT(func-no-repeats, TRACE_FUNC_OPT_NO_REPEATS) },
+	{ } /* Always set a last empty entry */
+};
+
+static struct tracer_flags func_flags = {
+	.val = TRACE_FUNC_NO_OPTS, /* By default: all flags disabled */
+	.opts = func_opts
+};
+
+static void tracing_start_function_trace(struct trace_array *tr)
+{
+	tr->function_enabled = 0;
+	register_ftrace_function(tr->ops);
+	tr->function_enabled = 1;
+}
+
+static void tracing_stop_function_trace(struct trace_array *tr)
+{
+	tr->function_enabled = 0;
+	unregister_ftrace_function(tr->ops);
+}
+
+static struct tracer function_trace;
+
+static int
+func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
+{
+	ftrace_func_t func;
+	u32 new_flags;
+
+	/* Do nothing if already set. */
+	if (!!set == !!(func_flags.val & bit))
+		return 0;
+
+	/* We can change this flag only when not running. */
+	if (tr->current_trace != &function_trace)
+		return 0;
+
+	new_flags = (func_flags.val & ~bit) | (set ? bit : 0);
+	func = select_trace_function(new_flags);
+	if (!func)
+		return -EINVAL;
+
+	/* Check if there's anything to change. */
+	if (tr->ops->func == func)
+		return 0;
+
+	if (!handle_func_repeats(tr, new_flags))
+		return -ENOMEM;
+
+	unregister_ftrace_function(tr->ops);
+	tr->ops->func = func;
+	register_ftrace_function(tr->ops);
+
+	return 0;
+}
+
+static struct tracer function_trace __tracer_data =
+{
+	.name		= "function",
+	.init		= function_trace_init,
+	.reset		= function_trace_reset,
+	.start		= function_trace_start,
+	.flags		= &func_flags,
+	.set_flag	= func_set_flag,
+	.allow_instances = true,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest	= trace_selftest_startup_function,
+#endif
+};
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+static void update_traceon_count(struct ftrace_probe_ops *ops,
+				 unsigned long ip,
+				 struct trace_array *tr, bool on,
+				 void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+	long *count;
+	long old_count;
+
+	/*
+	 * Tracing gets disabled (or enabled) once per count.
+	 * This function can be called at the same time on multiple CPUs.
+	 * It is fine if both disable (or enable) tracing, as disabling
+	 * (or enabling) the second time doesn't do anything as the
+	 * state of the tracer is already disabled (or enabled).
+	 * What needs to be synchronized in this case is that the count
+	 * only gets decremented once, even if the tracer is disabled
+	 * (or enabled) twice, as the second one is really a nop.
+	 *
+	 * The memory barriers guarantee that we only decrement the
+	 * counter once. First the count is read to a local variable
+	 * and a read barrier is used to make sure that it is loaded
+	 * before checking if the tracer is in the state we want.
+	 * If the tracer is not in the state we want, then the count
+	 * is guaranteed to be the old count.
+	 *
+	 * Next the tracer is set to the state we want (disabled or enabled)
+	 * then a write memory barrier is used to make sure that
+	 * the new state is visible before changing the counter by
+	 * one minus the old counter. This guarantees that another CPU
+	 * executing this code will see the new state before seeing
+	 * the new counter value, and would not do anything if the new
+	 * counter is seen.
+	 *
+	 * Note, there is no synchronization between this and a user
+	 * setting the tracing_on file. But we currently don't care
+	 * about that.
+	 */
+	count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
+	old_count = *count;
+
+	if (old_count <= 0)
+		return;
+
+	/* Make sure we see count before checking tracing state */
+	smp_rmb();
+
+	if (on == !!tracer_tracing_is_on(tr))
+		return;
+
+	if (on)
+		tracer_tracing_on(tr);
+	else
+		tracer_tracing_off(tr);
+
+	/* Make sure tracing state is visible before updating count */
+	smp_wmb();
+
+	*count = old_count - 1;
+}
+
+static void
+ftrace_traceon_count(unsigned long ip, unsigned long parent_ip,
+		     struct trace_array *tr, struct ftrace_probe_ops *ops,
+		     void *data)
+{
+	update_traceon_count(ops, ip, tr, 1, data);
+}
+
+static void
+ftrace_traceoff_count(unsigned long ip, unsigned long parent_ip,
+		      struct trace_array *tr, struct ftrace_probe_ops *ops,
+		      void *data)
+{
+	update_traceon_count(ops, ip, tr, 0, data);
+}
+
+static void
+ftrace_traceon(unsigned long ip, unsigned long parent_ip,
+	       struct trace_array *tr, struct ftrace_probe_ops *ops,
+	       void *data)
+{
+	if (tracer_tracing_is_on(tr))
+		return;
+
+	tracer_tracing_on(tr);
+}
+
+static void
+ftrace_traceoff(unsigned long ip, unsigned long parent_ip,
+		struct trace_array *tr, struct ftrace_probe_ops *ops,
+		void *data)
+{
+	if (!tracer_tracing_is_on(tr))
+		return;
+
+	tracer_tracing_off(tr);
+}
+
+#ifdef CONFIG_UNWINDER_ORC
+/*
+ * Skip 3:
+ *
+ *   function_trace_probe_call()
+ *   ftrace_ops_assist_func()
+ *   ftrace_call()
+ */
+#define FTRACE_STACK_SKIP 3
+#else
+/*
+ * Skip 5:
+ *
+ *   __trace_stack()
+ *   ftrace_stacktrace()
+ *   function_trace_probe_call()
+ *   ftrace_ops_assist_func()
+ *   ftrace_call()
+ */
+#define FTRACE_STACK_SKIP 5
+#endif
+
+static __always_inline void trace_stack(struct trace_array *tr)
+{
+	unsigned int trace_ctx;
+
+	trace_ctx = tracing_gen_ctx();
+
+	__trace_stack(tr, trace_ctx, FTRACE_STACK_SKIP);
+}
+
+static void
+ftrace_stacktrace(unsigned long ip, unsigned long parent_ip,
+		  struct trace_array *tr, struct ftrace_probe_ops *ops,
+		  void *data)
+{
+	trace_stack(tr);
+}
+
+static void
+ftrace_stacktrace_count(unsigned long ip, unsigned long parent_ip,
+			struct trace_array *tr, struct ftrace_probe_ops *ops,
+			void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+	long *count;
+	long old_count;
+	long new_count;
+
+	if (!tracing_is_on())
+		return;
+
+	/* unlimited? */
+	if (!mapper) {
+		trace_stack(tr);
+		return;
+	}
+
+	count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
+
+	/*
+	 * Stack traces should only execute the number of times the
+	 * user specified in the counter.
+	 */
+	do {
+		old_count = *count;
+
+		if (!old_count)
+			return;
+
+		new_count = old_count - 1;
+		new_count = cmpxchg(count, old_count, new_count);
+		if (new_count == old_count)
+			trace_stack(tr);
+
+		if (!tracing_is_on())
+			return;
+
+	} while (new_count != old_count);
+}
+
+static int update_count(struct ftrace_probe_ops *ops, unsigned long ip,
+			void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+	long *count = NULL;
+
+	if (mapper)
+		count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
+
+	if (count) {
+		if (*count <= 0)
+			return 0;
+		(*count)--;
+	}
+
+	return 1;
+}
+
+static void
+ftrace_dump_probe(unsigned long ip, unsigned long parent_ip,
+		  struct trace_array *tr, struct ftrace_probe_ops *ops,
+		  void *data)
+{
+	if (update_count(ops, ip, data))
+		ftrace_dump(DUMP_ALL);
+}
+
+/* Only dump the current CPU buffer. */
+static void
+ftrace_cpudump_probe(unsigned long ip, unsigned long parent_ip,
+		     struct trace_array *tr, struct ftrace_probe_ops *ops,
+		     void *data)
+{
+	if (update_count(ops, ip, data))
+		ftrace_dump(DUMP_ORIG);
+}
+
+static int
+ftrace_probe_print(const char *name, struct seq_file *m,
+		   unsigned long ip, struct ftrace_probe_ops *ops,
+		   void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+	long *count = NULL;
+
+	seq_printf(m, "%ps:%s", (void *)ip, name);
+
+	if (mapper)
+		count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
+
+	if (count)
+		seq_printf(m, ":count=%ld\n", *count);
+	else
+		seq_puts(m, ":unlimited\n");
+
+	return 0;
+}
+
+static int
+ftrace_traceon_print(struct seq_file *m, unsigned long ip,
+		     struct ftrace_probe_ops *ops,
+		     void *data)
+{
+	return ftrace_probe_print("traceon", m, ip, ops, data);
+}
+
+static int
+ftrace_traceoff_print(struct seq_file *m, unsigned long ip,
+			 struct ftrace_probe_ops *ops, void *data)
+{
+	return ftrace_probe_print("traceoff", m, ip, ops, data);
+}
+
+static int
+ftrace_stacktrace_print(struct seq_file *m, unsigned long ip,
+			struct ftrace_probe_ops *ops, void *data)
+{
+	return ftrace_probe_print("stacktrace", m, ip, ops, data);
+}
+
+static int
+ftrace_dump_print(struct seq_file *m, unsigned long ip,
+			struct ftrace_probe_ops *ops, void *data)
+{
+	return ftrace_probe_print("dump", m, ip, ops, data);
+}
+
+static int
+ftrace_cpudump_print(struct seq_file *m, unsigned long ip,
+			struct ftrace_probe_ops *ops, void *data)
+{
+	return ftrace_probe_print("cpudump", m, ip, ops, data);
+}
+
+
+static int
+ftrace_count_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
+		  unsigned long ip, void *init_data, void **data)
+{
+	struct ftrace_func_mapper *mapper = *data;
+
+	if (!mapper) {
+		mapper = allocate_ftrace_func_mapper();
+		if (!mapper)
+			return -ENOMEM;
+		*data = mapper;
+	}
+
+	return ftrace_func_mapper_add_ip(mapper, ip, init_data);
+}
+
+static void
+ftrace_count_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
+		  unsigned long ip, void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+
+	if (!ip) {
+		free_ftrace_func_mapper(mapper, NULL);
+		return;
+	}
+
+	ftrace_func_mapper_remove_ip(mapper, ip);
+}
+
+static struct ftrace_probe_ops traceon_count_probe_ops = {
+	.func			= ftrace_traceon_count,
+	.print			= ftrace_traceon_print,
+	.init			= ftrace_count_init,
+	.free			= ftrace_count_free,
+};
+
+static struct ftrace_probe_ops traceoff_count_probe_ops = {
+	.func			= ftrace_traceoff_count,
+	.print			= ftrace_traceoff_print,
+	.init			= ftrace_count_init,
+	.free			= ftrace_count_free,
+};
+
+static struct ftrace_probe_ops stacktrace_count_probe_ops = {
+	.func			= ftrace_stacktrace_count,
+	.print			= ftrace_stacktrace_print,
+	.init			= ftrace_count_init,
+	.free			= ftrace_count_free,
+};
+
+static struct ftrace_probe_ops dump_probe_ops = {
+	.func			= ftrace_dump_probe,
+	.print			= ftrace_dump_print,
+	.init			= ftrace_count_init,
+	.free			= ftrace_count_free,
+};
+
+static struct ftrace_probe_ops cpudump_probe_ops = {
+	.func			= ftrace_cpudump_probe,
+	.print			= ftrace_cpudump_print,
+};
+
+static struct ftrace_probe_ops traceon_probe_ops = {
+	.func			= ftrace_traceon,
+	.print			= ftrace_traceon_print,
+};
+
+static struct ftrace_probe_ops traceoff_probe_ops = {
+	.func			= ftrace_traceoff,
+	.print			= ftrace_traceoff_print,
+};
+
+static struct ftrace_probe_ops stacktrace_probe_ops = {
+	.func			= ftrace_stacktrace,
+	.print			= ftrace_stacktrace_print,
+};
+
+static int
+ftrace_trace_probe_callback(struct trace_array *tr,
+			    struct ftrace_probe_ops *ops,
+			    struct ftrace_hash *hash, char *glob,
+			    char *cmd, char *param, int enable)
+{
+	void *count = (void *)-1;
+	char *number;
+	int ret;
+
+	/* hash funcs only work with set_ftrace_filter */
+	if (!enable)
+		return -EINVAL;
+
+	if (glob[0] == '!')
+		return unregister_ftrace_function_probe_func(glob+1, tr, ops);
+
+	if (!param)
+		goto out_reg;
+
+	number = strsep(&param, ":");
+
+	if (!strlen(number))
+		goto out_reg;
+
+	/*
+	 * We use the callback data field (which is a pointer)
+	 * as our counter.
+	 */
+	ret = kstrtoul(number, 0, (unsigned long *)&count);
+	if (ret)
+		return ret;
+
+ out_reg:
+	ret = register_ftrace_function_probe(glob, tr, ops, count);
+
+	return ret < 0 ? ret : 0;
+}
+
+static int
+ftrace_trace_onoff_callback(struct trace_array *tr, struct ftrace_hash *hash,
+			    char *glob, char *cmd, char *param, int enable)
+{
+	struct ftrace_probe_ops *ops;
+
+	if (!tr)
+		return -ENODEV;
+
+	/* we register both traceon and traceoff to this callback */
+	if (strcmp(cmd, "traceon") == 0)
+		ops = param ? &traceon_count_probe_ops : &traceon_probe_ops;
+	else
+		ops = param ? &traceoff_count_probe_ops : &traceoff_probe_ops;
+
+	return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
+					   param, enable);
+}
+
+static int
+ftrace_stacktrace_callback(struct trace_array *tr, struct ftrace_hash *hash,
+			   char *glob, char *cmd, char *param, int enable)
+{
+	struct ftrace_probe_ops *ops;
+
+	if (!tr)
+		return -ENODEV;
+
+	ops = param ? &stacktrace_count_probe_ops : &stacktrace_probe_ops;
+
+	return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
+					   param, enable);
+}
+
+static int
+ftrace_dump_callback(struct trace_array *tr, struct ftrace_hash *hash,
+			   char *glob, char *cmd, char *param, int enable)
+{
+	struct ftrace_probe_ops *ops;
+
+	if (!tr)
+		return -ENODEV;
+
+	ops = &dump_probe_ops;
+
+	/* Only dump once. */
+	return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
+					   "1", enable);
+}
+
+static int
+ftrace_cpudump_callback(struct trace_array *tr, struct ftrace_hash *hash,
+			   char *glob, char *cmd, char *param, int enable)
+{
+	struct ftrace_probe_ops *ops;
+
+	if (!tr)
+		return -ENODEV;
+
+	ops = &cpudump_probe_ops;
+
+	/* Only dump once. */
+	return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
+					   "1", enable);
+}
+
+static struct ftrace_func_command ftrace_traceon_cmd = {
+	.name			= "traceon",
+	.func			= ftrace_trace_onoff_callback,
+};
+
+static struct ftrace_func_command ftrace_traceoff_cmd = {
+	.name			= "traceoff",
+	.func			= ftrace_trace_onoff_callback,
+};
+
+static struct ftrace_func_command ftrace_stacktrace_cmd = {
+	.name			= "stacktrace",
+	.func			= ftrace_stacktrace_callback,
+};
+
+static struct ftrace_func_command ftrace_dump_cmd = {
+	.name			= "dump",
+	.func			= ftrace_dump_callback,
+};
+
+static struct ftrace_func_command ftrace_cpudump_cmd = {
+	.name			= "cpudump",
+	.func			= ftrace_cpudump_callback,
+};
+
+static int __init init_func_cmd_traceon(void)
+{
+	int ret;
+
+	ret = register_ftrace_command(&ftrace_traceoff_cmd);
+	if (ret)
+		return ret;
+
+	ret = register_ftrace_command(&ftrace_traceon_cmd);
+	if (ret)
+		goto out_free_traceoff;
+
+	ret = register_ftrace_command(&ftrace_stacktrace_cmd);
+	if (ret)
+		goto out_free_traceon;
+
+	ret = register_ftrace_command(&ftrace_dump_cmd);
+	if (ret)
+		goto out_free_stacktrace;
+
+	ret = register_ftrace_command(&ftrace_cpudump_cmd);
+	if (ret)
+		goto out_free_dump;
+
+	return 0;
+
+ out_free_dump:
+	unregister_ftrace_command(&ftrace_dump_cmd);
+ out_free_stacktrace:
+	unregister_ftrace_command(&ftrace_stacktrace_cmd);
+ out_free_traceon:
+	unregister_ftrace_command(&ftrace_traceon_cmd);
+ out_free_traceoff:
+	unregister_ftrace_command(&ftrace_traceoff_cmd);
+
+	return ret;
+}
+#else
+static inline int init_func_cmd_traceon(void)
+{
+	return 0;
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+__init int init_function_trace(void)
+{
+	init_func_cmd_traceon();
+	return register_tracer(&function_trace);
+}
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
new file mode 100644
index 000000000..203204cad
--- /dev/null
+++ b/kernel/trace/trace_functions_graph.c
@@ -0,0 +1,1367 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *
+ * Function graph tracer.
+ * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
+ * Mostly borrowed from function tracer which
+ * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
+ *
+ */
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+
+#include "trace.h"
+#include "trace_output.h"
+
+/* When set, irq functions will be ignored */
+static int ftrace_graph_skip_irqs;
+
+struct fgraph_cpu_data {
+	pid_t		last_pid;
+	int		depth;
+	int		depth_irq;
+	int		ignore;
+	unsigned long	enter_funcs[FTRACE_RETFUNC_DEPTH];
+};
+
+struct fgraph_data {
+	struct fgraph_cpu_data __percpu *cpu_data;
+
+	/* Place to preserve last processed entry. */
+	struct ftrace_graph_ent_entry	ent;
+	struct ftrace_graph_ret_entry	ret;
+	int				failed;
+	int				cpu;
+};
+
+#define TRACE_GRAPH_INDENT	2
+
+unsigned int fgraph_max_depth;
+
+static struct tracer_opt trace_opts[] = {
+	/* Display overruns? (for self-debug purpose) */
+	{ TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
+	/* Display CPU ? */
+	{ TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
+	/* Display Overhead ? */
+	{ TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
+	/* Display proc name/pid */
+	{ TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
+	/* Display duration of execution */
+	{ TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
+	/* Display absolute time of an entry */
+	{ TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
+	/* Display interrupts */
+	{ TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
+	/* Display function name after trailing } */
+	{ TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
+	/* Include sleep time (scheduled out) between entry and return */
+	{ TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
+
+#ifdef CONFIG_FUNCTION_PROFILER
+	/* Include time within nested functions */
+	{ TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
+#endif
+
+	{ } /* Empty entry */
+};
+
+static struct tracer_flags tracer_flags = {
+	/* Don't display overruns, proc, or tail by default */
+	.val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
+	       TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS |
+	       TRACE_GRAPH_SLEEP_TIME | TRACE_GRAPH_GRAPH_TIME,
+	.opts = trace_opts
+};
+
+static struct trace_array *graph_array;
+
+/*
+ * DURATION column is being also used to display IRQ signs,
+ * following values are used by print_graph_irq and others
+ * to fill in space into DURATION column.
+ */
+enum {
+	FLAGS_FILL_FULL  = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
+	FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
+	FLAGS_FILL_END   = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
+};
+
+static void
+print_graph_duration(struct trace_array *tr, unsigned long long duration,
+		     struct trace_seq *s, u32 flags);
+
+int __trace_graph_entry(struct trace_array *tr,
+				struct ftrace_graph_ent *trace,
+				unsigned int trace_ctx)
+{
+	struct trace_event_call *call = &event_funcgraph_entry;
+	struct ring_buffer_event *event;
+	struct trace_buffer *buffer = tr->array_buffer.buffer;
+	struct ftrace_graph_ent_entry *entry;
+
+	event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
+					  sizeof(*entry), trace_ctx);
+	if (!event)
+		return 0;
+	entry	= ring_buffer_event_data(event);
+	entry->graph_ent			= *trace;
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit_nostack(buffer, event);
+
+	return 1;
+}
+
+static inline int ftrace_graph_ignore_irqs(void)
+{
+	if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
+		return 0;
+
+	return in_hardirq();
+}
+
+int trace_graph_entry(struct ftrace_graph_ent *trace)
+{
+	struct trace_array *tr = graph_array;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	unsigned int trace_ctx;
+	long disabled;
+	int ret;
+	int cpu;
+
+	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
+		return 0;
+
+	/*
+	 * Do not trace a function if it's filtered by set_graph_notrace.
+	 * Make the index of ret stack negative to indicate that it should
+	 * ignore further functions.  But it needs its own ret stack entry
+	 * to recover the original index in order to continue tracing after
+	 * returning from the function.
+	 */
+	if (ftrace_graph_notrace_addr(trace->func)) {
+		trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT);
+		/*
+		 * Need to return 1 to have the return called
+		 * that will clear the NOTRACE bit.
+		 */
+		return 1;
+	}
+
+	if (!ftrace_trace_task(tr))
+		return 0;
+
+	if (ftrace_graph_ignore_func(trace))
+		return 0;
+
+	if (ftrace_graph_ignore_irqs())
+		return 0;
+
+	/*
+	 * Stop here if tracing_threshold is set. We only write function return
+	 * events to the ring buffer.
+	 */
+	if (tracing_thresh)
+		return 1;
+
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+	disabled = atomic_inc_return(&data->disabled);
+	if (likely(disabled == 1)) {
+		trace_ctx = tracing_gen_ctx_flags(flags);
+		ret = __trace_graph_entry(tr, trace, trace_ctx);
+	} else {
+		ret = 0;
+	}
+
+	atomic_dec(&data->disabled);
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static void
+__trace_graph_function(struct trace_array *tr,
+		unsigned long ip, unsigned int trace_ctx)
+{
+	u64 time = trace_clock_local();
+	struct ftrace_graph_ent ent = {
+		.func  = ip,
+		.depth = 0,
+	};
+	struct ftrace_graph_ret ret = {
+		.func     = ip,
+		.depth    = 0,
+		.calltime = time,
+		.rettime  = time,
+	};
+
+	__trace_graph_entry(tr, &ent, trace_ctx);
+	__trace_graph_return(tr, &ret, trace_ctx);
+}
+
+void
+trace_graph_function(struct trace_array *tr,
+		unsigned long ip, unsigned long parent_ip,
+		unsigned int trace_ctx)
+{
+	__trace_graph_function(tr, ip, trace_ctx);
+}
+
+void __trace_graph_return(struct trace_array *tr,
+				struct ftrace_graph_ret *trace,
+				unsigned int trace_ctx)
+{
+	struct trace_event_call *call = &event_funcgraph_exit;
+	struct ring_buffer_event *event;
+	struct trace_buffer *buffer = tr->array_buffer.buffer;
+	struct ftrace_graph_ret_entry *entry;
+
+	event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
+					  sizeof(*entry), trace_ctx);
+	if (!event)
+		return;
+	entry	= ring_buffer_event_data(event);
+	entry->ret				= *trace;
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit_nostack(buffer, event);
+}
+
+void trace_graph_return(struct ftrace_graph_ret *trace)
+{
+	struct trace_array *tr = graph_array;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	unsigned int trace_ctx;
+	long disabled;
+	int cpu;
+
+	ftrace_graph_addr_finish(trace);
+
+	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
+		trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
+		return;
+	}
+
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+	disabled = atomic_inc_return(&data->disabled);
+	if (likely(disabled == 1)) {
+		trace_ctx = tracing_gen_ctx_flags(flags);
+		__trace_graph_return(tr, trace, trace_ctx);
+	}
+	atomic_dec(&data->disabled);
+	local_irq_restore(flags);
+}
+
+void set_graph_array(struct trace_array *tr)
+{
+	graph_array = tr;
+
+	/* Make graph_array visible before we start tracing */
+
+	smp_mb();
+}
+
+static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
+{
+	ftrace_graph_addr_finish(trace);
+
+	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
+		trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
+		return;
+	}
+
+	if (tracing_thresh &&
+	    (trace->rettime - trace->calltime < tracing_thresh))
+		return;
+	else
+		trace_graph_return(trace);
+}
+
+static struct fgraph_ops funcgraph_thresh_ops = {
+	.entryfunc = &trace_graph_entry,
+	.retfunc = &trace_graph_thresh_return,
+};
+
+static struct fgraph_ops funcgraph_ops = {
+	.entryfunc = &trace_graph_entry,
+	.retfunc = &trace_graph_return,
+};
+
+static int graph_trace_init(struct trace_array *tr)
+{
+	int ret;
+
+	set_graph_array(tr);
+	if (tracing_thresh)
+		ret = register_ftrace_graph(&funcgraph_thresh_ops);
+	else
+		ret = register_ftrace_graph(&funcgraph_ops);
+	if (ret)
+		return ret;
+	tracing_start_cmdline_record();
+
+	return 0;
+}
+
+static void graph_trace_reset(struct trace_array *tr)
+{
+	tracing_stop_cmdline_record();
+	if (tracing_thresh)
+		unregister_ftrace_graph(&funcgraph_thresh_ops);
+	else
+		unregister_ftrace_graph(&funcgraph_ops);
+}
+
+static int graph_trace_update_thresh(struct trace_array *tr)
+{
+	graph_trace_reset(tr);
+	return graph_trace_init(tr);
+}
+
+static int max_bytes_for_cpu;
+
+static void print_graph_cpu(struct trace_seq *s, int cpu)
+{
+	/*
+	 * Start with a space character - to make it stand out
+	 * to the right a bit when trace output is pasted into
+	 * email:
+	 */
+	trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
+}
+
+#define TRACE_GRAPH_PROCINFO_LENGTH	14
+
+static void print_graph_proc(struct trace_seq *s, pid_t pid)
+{
+	char comm[TASK_COMM_LEN];
+	/* sign + log10(MAX_INT) + '\0' */
+	char pid_str[11];
+	int spaces = 0;
+	int len;
+	int i;
+
+	trace_find_cmdline(pid, comm);
+	comm[7] = '\0';
+	sprintf(pid_str, "%d", pid);
+
+	/* 1 stands for the "-" character */
+	len = strlen(comm) + strlen(pid_str) + 1;
+
+	if (len < TRACE_GRAPH_PROCINFO_LENGTH)
+		spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
+
+	/* First spaces to align center */
+	for (i = 0; i < spaces / 2; i++)
+		trace_seq_putc(s, ' ');
+
+	trace_seq_printf(s, "%s-%s", comm, pid_str);
+
+	/* Last spaces to align center */
+	for (i = 0; i < spaces - (spaces / 2); i++)
+		trace_seq_putc(s, ' ');
+}
+
+
+static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
+{
+	trace_seq_putc(s, ' ');
+	trace_print_lat_fmt(s, entry);
+	trace_seq_puts(s, " | ");
+}
+
+/* If the pid changed since the last trace, output this event */
+static void
+verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
+{
+	pid_t prev_pid;
+	pid_t *last_pid;
+
+	if (!data)
+		return;
+
+	last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
+
+	if (*last_pid == pid)
+		return;
+
+	prev_pid = *last_pid;
+	*last_pid = pid;
+
+	if (prev_pid == -1)
+		return;
+/*
+ * Context-switch trace line:
+
+ ------------------------------------------
+ | 1)  migration/0--1  =>  sshd-1755
+ ------------------------------------------
+
+ */
+	trace_seq_puts(s, " ------------------------------------------\n");
+	print_graph_cpu(s, cpu);
+	print_graph_proc(s, prev_pid);
+	trace_seq_puts(s, " => ");
+	print_graph_proc(s, pid);
+	trace_seq_puts(s, "\n ------------------------------------------\n\n");
+}
+
+static struct ftrace_graph_ret_entry *
+get_return_for_leaf(struct trace_iterator *iter,
+		struct ftrace_graph_ent_entry *curr)
+{
+	struct fgraph_data *data = iter->private;
+	struct ring_buffer_iter *ring_iter = NULL;
+	struct ring_buffer_event *event;
+	struct ftrace_graph_ret_entry *next;
+
+	/*
+	 * If the previous output failed to write to the seq buffer,
+	 * then we just reuse the data from before.
+	 */
+	if (data && data->failed) {
+		curr = &data->ent;
+		next = &data->ret;
+	} else {
+
+		ring_iter = trace_buffer_iter(iter, iter->cpu);
+
+		/* First peek to compare current entry and the next one */
+		if (ring_iter)
+			event = ring_buffer_iter_peek(ring_iter, NULL);
+		else {
+			/*
+			 * We need to consume the current entry to see
+			 * the next one.
+			 */
+			ring_buffer_consume(iter->array_buffer->buffer, iter->cpu,
+					    NULL, NULL);
+			event = ring_buffer_peek(iter->array_buffer->buffer, iter->cpu,
+						 NULL, NULL);
+		}
+
+		if (!event)
+			return NULL;
+
+		next = ring_buffer_event_data(event);
+
+		if (data) {
+			/*
+			 * Save current and next entries for later reference
+			 * if the output fails.
+			 */
+			data->ent = *curr;
+			/*
+			 * If the next event is not a return type, then
+			 * we only care about what type it is. Otherwise we can
+			 * safely copy the entire event.
+			 */
+			if (next->ent.type == TRACE_GRAPH_RET)
+				data->ret = *next;
+			else
+				data->ret.ent.type = next->ent.type;
+		}
+	}
+
+	if (next->ent.type != TRACE_GRAPH_RET)
+		return NULL;
+
+	if (curr->ent.pid != next->ent.pid ||
+			curr->graph_ent.func != next->ret.func)
+		return NULL;
+
+	/* this is a leaf, now advance the iterator */
+	if (ring_iter)
+		ring_buffer_iter_advance(ring_iter);
+
+	return next;
+}
+
+static void print_graph_abs_time(u64 t, struct trace_seq *s)
+{
+	unsigned long usecs_rem;
+
+	usecs_rem = do_div(t, NSEC_PER_SEC);
+	usecs_rem /= 1000;
+
+	trace_seq_printf(s, "%5lu.%06lu |  ",
+			 (unsigned long)t, usecs_rem);
+}
+
+static void
+print_graph_rel_time(struct trace_iterator *iter, struct trace_seq *s)
+{
+	unsigned long long usecs;
+
+	usecs = iter->ts - iter->array_buffer->time_start;
+	do_div(usecs, NSEC_PER_USEC);
+
+	trace_seq_printf(s, "%9llu us |  ", usecs);
+}
+
+static void
+print_graph_irq(struct trace_iterator *iter, unsigned long addr,
+		enum trace_type type, int cpu, pid_t pid, u32 flags)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *ent = iter->ent;
+
+	if (addr < (unsigned long)__irqentry_text_start ||
+		addr >= (unsigned long)__irqentry_text_end)
+		return;
+
+	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
+		/* Absolute time */
+		if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
+			print_graph_abs_time(iter->ts, s);
+
+		/* Relative time */
+		if (flags & TRACE_GRAPH_PRINT_REL_TIME)
+			print_graph_rel_time(iter, s);
+
+		/* Cpu */
+		if (flags & TRACE_GRAPH_PRINT_CPU)
+			print_graph_cpu(s, cpu);
+
+		/* Proc */
+		if (flags & TRACE_GRAPH_PRINT_PROC) {
+			print_graph_proc(s, pid);
+			trace_seq_puts(s, " | ");
+		}
+
+		/* Latency format */
+		if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
+			print_graph_lat_fmt(s, ent);
+	}
+
+	/* No overhead */
+	print_graph_duration(tr, 0, s, flags | FLAGS_FILL_START);
+
+	if (type == TRACE_GRAPH_ENT)
+		trace_seq_puts(s, "==========>");
+	else
+		trace_seq_puts(s, "<==========");
+
+	print_graph_duration(tr, 0, s, flags | FLAGS_FILL_END);
+	trace_seq_putc(s, '\n');
+}
+
+void
+trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
+{
+	unsigned long nsecs_rem = do_div(duration, 1000);
+	/* log10(ULONG_MAX) + '\0' */
+	char usecs_str[21];
+	char nsecs_str[5];
+	int len;
+	int i;
+
+	sprintf(usecs_str, "%lu", (unsigned long) duration);
+
+	/* Print msecs */
+	trace_seq_printf(s, "%s", usecs_str);
+
+	len = strlen(usecs_str);
+
+	/* Print nsecs (we don't want to exceed 7 numbers) */
+	if (len < 7) {
+		size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
+
+		snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
+		trace_seq_printf(s, ".%s", nsecs_str);
+		len += strlen(nsecs_str) + 1;
+	}
+
+	trace_seq_puts(s, " us ");
+
+	/* Print remaining spaces to fit the row's width */
+	for (i = len; i < 8; i++)
+		trace_seq_putc(s, ' ');
+}
+
+static void
+print_graph_duration(struct trace_array *tr, unsigned long long duration,
+		     struct trace_seq *s, u32 flags)
+{
+	if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
+	    !(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
+		return;
+
+	/* No real adata, just filling the column with spaces */
+	switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
+	case FLAGS_FILL_FULL:
+		trace_seq_puts(s, "              |  ");
+		return;
+	case FLAGS_FILL_START:
+		trace_seq_puts(s, "  ");
+		return;
+	case FLAGS_FILL_END:
+		trace_seq_puts(s, " |");
+		return;
+	}
+
+	/* Signal a overhead of time execution to the output */
+	if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
+		trace_seq_printf(s, "%c ", trace_find_mark(duration));
+	else
+		trace_seq_puts(s, "  ");
+
+	trace_print_graph_duration(duration, s);
+	trace_seq_puts(s, "|  ");
+}
+
+/* Case of a leaf function on its call entry */
+static enum print_line_t
+print_graph_entry_leaf(struct trace_iterator *iter,
+		struct ftrace_graph_ent_entry *entry,
+		struct ftrace_graph_ret_entry *ret_entry,
+		struct trace_seq *s, u32 flags)
+{
+	struct fgraph_data *data = iter->private;
+	struct trace_array *tr = iter->tr;
+	struct ftrace_graph_ret *graph_ret;
+	struct ftrace_graph_ent *call;
+	unsigned long long duration;
+	int cpu = iter->cpu;
+	int i;
+
+	graph_ret = &ret_entry->ret;
+	call = &entry->graph_ent;
+	duration = graph_ret->rettime - graph_ret->calltime;
+
+	if (data) {
+		struct fgraph_cpu_data *cpu_data;
+
+		cpu_data = per_cpu_ptr(data->cpu_data, cpu);
+
+		/*
+		 * Comments display at + 1 to depth. Since
+		 * this is a leaf function, keep the comments
+		 * equal to this depth.
+		 */
+		cpu_data->depth = call->depth - 1;
+
+		/* No need to keep this function around for this depth */
+		if (call->depth < FTRACE_RETFUNC_DEPTH &&
+		    !WARN_ON_ONCE(call->depth < 0))
+			cpu_data->enter_funcs[call->depth] = 0;
+	}
+
+	/* Overhead and duration */
+	print_graph_duration(tr, duration, s, flags);
+
+	/* Function */
+	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
+		trace_seq_putc(s, ' ');
+
+	trace_seq_printf(s, "%ps();\n", (void *)call->func);
+
+	print_graph_irq(iter, graph_ret->func, TRACE_GRAPH_RET,
+			cpu, iter->ent->pid, flags);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t
+print_graph_entry_nested(struct trace_iterator *iter,
+			 struct ftrace_graph_ent_entry *entry,
+			 struct trace_seq *s, int cpu, u32 flags)
+{
+	struct ftrace_graph_ent *call = &entry->graph_ent;
+	struct fgraph_data *data = iter->private;
+	struct trace_array *tr = iter->tr;
+	int i;
+
+	if (data) {
+		struct fgraph_cpu_data *cpu_data;
+		int cpu = iter->cpu;
+
+		cpu_data = per_cpu_ptr(data->cpu_data, cpu);
+		cpu_data->depth = call->depth;
+
+		/* Save this function pointer to see if the exit matches */
+		if (call->depth < FTRACE_RETFUNC_DEPTH &&
+		    !WARN_ON_ONCE(call->depth < 0))
+			cpu_data->enter_funcs[call->depth] = call->func;
+	}
+
+	/* No time */
+	print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
+
+	/* Function */
+	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
+		trace_seq_putc(s, ' ');
+
+	trace_seq_printf(s, "%ps() {\n", (void *)call->func);
+
+	if (trace_seq_has_overflowed(s))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	/*
+	 * we already consumed the current entry to check the next one
+	 * and see if this is a leaf.
+	 */
+	return TRACE_TYPE_NO_CONSUME;
+}
+
+static void
+print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
+		     int type, unsigned long addr, u32 flags)
+{
+	struct fgraph_data *data = iter->private;
+	struct trace_entry *ent = iter->ent;
+	struct trace_array *tr = iter->tr;
+	int cpu = iter->cpu;
+
+	/* Pid */
+	verif_pid(s, ent->pid, cpu, data);
+
+	if (type)
+		/* Interrupt */
+		print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
+
+	if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
+		return;
+
+	/* Absolute time */
+	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
+		print_graph_abs_time(iter->ts, s);
+
+	/* Relative time */
+	if (flags & TRACE_GRAPH_PRINT_REL_TIME)
+		print_graph_rel_time(iter, s);
+
+	/* Cpu */
+	if (flags & TRACE_GRAPH_PRINT_CPU)
+		print_graph_cpu(s, cpu);
+
+	/* Proc */
+	if (flags & TRACE_GRAPH_PRINT_PROC) {
+		print_graph_proc(s, ent->pid);
+		trace_seq_puts(s, " | ");
+	}
+
+	/* Latency format */
+	if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
+		print_graph_lat_fmt(s, ent);
+
+	return;
+}
+
+/*
+ * Entry check for irq code
+ *
+ * returns 1 if
+ *  - we are inside irq code
+ *  - we just entered irq code
+ *
+ * returns 0 if
+ *  - funcgraph-interrupts option is set
+ *  - we are not inside irq code
+ */
+static int
+check_irq_entry(struct trace_iterator *iter, u32 flags,
+		unsigned long addr, int depth)
+{
+	int cpu = iter->cpu;
+	int *depth_irq;
+	struct fgraph_data *data = iter->private;
+
+	/*
+	 * If we are either displaying irqs, or we got called as
+	 * a graph event and private data does not exist,
+	 * then we bypass the irq check.
+	 */
+	if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
+	    (!data))
+		return 0;
+
+	depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
+
+	/*
+	 * We are inside the irq code
+	 */
+	if (*depth_irq >= 0)
+		return 1;
+
+	if ((addr < (unsigned long)__irqentry_text_start) ||
+	    (addr >= (unsigned long)__irqentry_text_end))
+		return 0;
+
+	/*
+	 * We are entering irq code.
+	 */
+	*depth_irq = depth;
+	return 1;
+}
+
+/*
+ * Return check for irq code
+ *
+ * returns 1 if
+ *  - we are inside irq code
+ *  - we just left irq code
+ *
+ * returns 0 if
+ *  - funcgraph-interrupts option is set
+ *  - we are not inside irq code
+ */
+static int
+check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
+{
+	int cpu = iter->cpu;
+	int *depth_irq;
+	struct fgraph_data *data = iter->private;
+
+	/*
+	 * If we are either displaying irqs, or we got called as
+	 * a graph event and private data does not exist,
+	 * then we bypass the irq check.
+	 */
+	if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
+	    (!data))
+		return 0;
+
+	depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
+
+	/*
+	 * We are not inside the irq code.
+	 */
+	if (*depth_irq == -1)
+		return 0;
+
+	/*
+	 * We are inside the irq code, and this is returning entry.
+	 * Let's not trace it and clear the entry depth, since
+	 * we are out of irq code.
+	 *
+	 * This condition ensures that we 'leave the irq code' once
+	 * we are out of the entry depth. Thus protecting us from
+	 * the RETURN entry loss.
+	 */
+	if (*depth_irq >= depth) {
+		*depth_irq = -1;
+		return 1;
+	}
+
+	/*
+	 * We are inside the irq code, and this is not the entry.
+	 */
+	return 1;
+}
+
+static enum print_line_t
+print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
+			struct trace_iterator *iter, u32 flags)
+{
+	struct fgraph_data *data = iter->private;
+	struct ftrace_graph_ent *call = &field->graph_ent;
+	struct ftrace_graph_ret_entry *leaf_ret;
+	static enum print_line_t ret;
+	int cpu = iter->cpu;
+
+	if (check_irq_entry(iter, flags, call->func, call->depth))
+		return TRACE_TYPE_HANDLED;
+
+	print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
+
+	leaf_ret = get_return_for_leaf(iter, field);
+	if (leaf_ret)
+		ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
+	else
+		ret = print_graph_entry_nested(iter, field, s, cpu, flags);
+
+	if (data) {
+		/*
+		 * If we failed to write our output, then we need to make
+		 * note of it. Because we already consumed our entry.
+		 */
+		if (s->full) {
+			data->failed = 1;
+			data->cpu = cpu;
+		} else
+			data->failed = 0;
+	}
+
+	return ret;
+}
+
+static enum print_line_t
+print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
+		   struct trace_entry *ent, struct trace_iterator *iter,
+		   u32 flags)
+{
+	unsigned long long duration = trace->rettime - trace->calltime;
+	struct fgraph_data *data = iter->private;
+	struct trace_array *tr = iter->tr;
+	pid_t pid = ent->pid;
+	int cpu = iter->cpu;
+	int func_match = 1;
+	int i;
+
+	if (check_irq_return(iter, flags, trace->depth))
+		return TRACE_TYPE_HANDLED;
+
+	if (data) {
+		struct fgraph_cpu_data *cpu_data;
+		int cpu = iter->cpu;
+
+		cpu_data = per_cpu_ptr(data->cpu_data, cpu);
+
+		/*
+		 * Comments display at + 1 to depth. This is the
+		 * return from a function, we now want the comments
+		 * to display at the same level of the bracket.
+		 */
+		cpu_data->depth = trace->depth - 1;
+
+		if (trace->depth < FTRACE_RETFUNC_DEPTH &&
+		    !WARN_ON_ONCE(trace->depth < 0)) {
+			if (cpu_data->enter_funcs[trace->depth] != trace->func)
+				func_match = 0;
+			cpu_data->enter_funcs[trace->depth] = 0;
+		}
+	}
+
+	print_graph_prologue(iter, s, 0, 0, flags);
+
+	/* Overhead and duration */
+	print_graph_duration(tr, duration, s, flags);
+
+	/* Closing brace */
+	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
+		trace_seq_putc(s, ' ');
+
+	/*
+	 * If the return function does not have a matching entry,
+	 * then the entry was lost. Instead of just printing
+	 * the '}' and letting the user guess what function this
+	 * belongs to, write out the function name. Always do
+	 * that if the funcgraph-tail option is enabled.
+	 */
+	if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
+		trace_seq_puts(s, "}\n");
+	else
+		trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
+
+	/* Overrun */
+	if (flags & TRACE_GRAPH_PRINT_OVERRUN)
+		trace_seq_printf(s, " (Overruns: %u)\n",
+				 trace->overrun);
+
+	print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
+			cpu, pid, flags);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t
+print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
+		    struct trace_iterator *iter, u32 flags)
+{
+	struct trace_array *tr = iter->tr;
+	unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
+	struct fgraph_data *data = iter->private;
+	struct trace_event *event;
+	int depth = 0;
+	int ret;
+	int i;
+
+	if (data)
+		depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
+
+	print_graph_prologue(iter, s, 0, 0, flags);
+
+	/* No time */
+	print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
+
+	/* Indentation */
+	if (depth > 0)
+		for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
+			trace_seq_putc(s, ' ');
+
+	/* The comment */
+	trace_seq_puts(s, "/* ");
+
+	switch (iter->ent->type) {
+	case TRACE_BPUTS:
+		ret = trace_print_bputs_msg_only(iter);
+		if (ret != TRACE_TYPE_HANDLED)
+			return ret;
+		break;
+	case TRACE_BPRINT:
+		ret = trace_print_bprintk_msg_only(iter);
+		if (ret != TRACE_TYPE_HANDLED)
+			return ret;
+		break;
+	case TRACE_PRINT:
+		ret = trace_print_printk_msg_only(iter);
+		if (ret != TRACE_TYPE_HANDLED)
+			return ret;
+		break;
+	default:
+		event = ftrace_find_event(ent->type);
+		if (!event)
+			return TRACE_TYPE_UNHANDLED;
+
+		ret = event->funcs->trace(iter, sym_flags, event);
+		if (ret != TRACE_TYPE_HANDLED)
+			return ret;
+	}
+
+	if (trace_seq_has_overflowed(s))
+		goto out;
+
+	/* Strip ending newline */
+	if (s->buffer[s->seq.len - 1] == '\n') {
+		s->buffer[s->seq.len - 1] = '\0';
+		s->seq.len--;
+	}
+
+	trace_seq_puts(s, " */\n");
+ out:
+	return trace_handle_return(s);
+}
+
+
+enum print_line_t
+print_graph_function_flags(struct trace_iterator *iter, u32 flags)
+{
+	struct ftrace_graph_ent_entry *field;
+	struct fgraph_data *data = iter->private;
+	struct trace_entry *entry = iter->ent;
+	struct trace_seq *s = &iter->seq;
+	int cpu = iter->cpu;
+	int ret;
+
+	if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
+		per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
+		return TRACE_TYPE_HANDLED;
+	}
+
+	/*
+	 * If the last output failed, there's a possibility we need
+	 * to print out the missing entry which would never go out.
+	 */
+	if (data && data->failed) {
+		field = &data->ent;
+		iter->cpu = data->cpu;
+		ret = print_graph_entry(field, s, iter, flags);
+		if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
+			per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
+			ret = TRACE_TYPE_NO_CONSUME;
+		}
+		iter->cpu = cpu;
+		return ret;
+	}
+
+	switch (entry->type) {
+	case TRACE_GRAPH_ENT: {
+		/*
+		 * print_graph_entry() may consume the current event,
+		 * thus @field may become invalid, so we need to save it.
+		 * sizeof(struct ftrace_graph_ent_entry) is very small,
+		 * it can be safely saved at the stack.
+		 */
+		struct ftrace_graph_ent_entry saved;
+		trace_assign_type(field, entry);
+		saved = *field;
+		return print_graph_entry(&saved, s, iter, flags);
+	}
+	case TRACE_GRAPH_RET: {
+		struct ftrace_graph_ret_entry *field;
+		trace_assign_type(field, entry);
+		return print_graph_return(&field->ret, s, entry, iter, flags);
+	}
+	case TRACE_STACK:
+	case TRACE_FN:
+		/* dont trace stack and functions as comments */
+		return TRACE_TYPE_UNHANDLED;
+
+	default:
+		return print_graph_comment(s, entry, iter, flags);
+	}
+
+	return TRACE_TYPE_HANDLED;
+}
+
+static enum print_line_t
+print_graph_function(struct trace_iterator *iter)
+{
+	return print_graph_function_flags(iter, tracer_flags.val);
+}
+
+static enum print_line_t
+print_graph_function_event(struct trace_iterator *iter, int flags,
+			   struct trace_event *event)
+{
+	return print_graph_function(iter);
+}
+
+static void print_lat_header(struct seq_file *s, u32 flags)
+{
+	static const char spaces[] = "                "	/* 16 spaces */
+		"    "					/* 4 spaces */
+		"                 ";			/* 17 spaces */
+	int size = 0;
+
+	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
+		size += 16;
+	if (flags & TRACE_GRAPH_PRINT_REL_TIME)
+		size += 16;
+	if (flags & TRACE_GRAPH_PRINT_CPU)
+		size += 4;
+	if (flags & TRACE_GRAPH_PRINT_PROC)
+		size += 17;
+
+	seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
+	seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
+	seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
+	seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
+	seq_printf(s, "#%.*s||| /                      \n", size, spaces);
+}
+
+static void __print_graph_headers_flags(struct trace_array *tr,
+					struct seq_file *s, u32 flags)
+{
+	int lat = tr->trace_flags & TRACE_ITER_LATENCY_FMT;
+
+	if (lat)
+		print_lat_header(s, flags);
+
+	/* 1st line */
+	seq_putc(s, '#');
+	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
+		seq_puts(s, "     TIME       ");
+	if (flags & TRACE_GRAPH_PRINT_REL_TIME)
+		seq_puts(s, "   REL TIME     ");
+	if (flags & TRACE_GRAPH_PRINT_CPU)
+		seq_puts(s, " CPU");
+	if (flags & TRACE_GRAPH_PRINT_PROC)
+		seq_puts(s, "  TASK/PID       ");
+	if (lat)
+		seq_puts(s, "||||   ");
+	if (flags & TRACE_GRAPH_PRINT_DURATION)
+		seq_puts(s, "  DURATION   ");
+	seq_puts(s, "               FUNCTION CALLS\n");
+
+	/* 2nd line */
+	seq_putc(s, '#');
+	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
+		seq_puts(s, "      |         ");
+	if (flags & TRACE_GRAPH_PRINT_REL_TIME)
+		seq_puts(s, "      |         ");
+	if (flags & TRACE_GRAPH_PRINT_CPU)
+		seq_puts(s, " |  ");
+	if (flags & TRACE_GRAPH_PRINT_PROC)
+		seq_puts(s, "   |    |        ");
+	if (lat)
+		seq_puts(s, "||||   ");
+	if (flags & TRACE_GRAPH_PRINT_DURATION)
+		seq_puts(s, "   |   |      ");
+	seq_puts(s, "               |   |   |   |\n");
+}
+
+static void print_graph_headers(struct seq_file *s)
+{
+	print_graph_headers_flags(s, tracer_flags.val);
+}
+
+void print_graph_headers_flags(struct seq_file *s, u32 flags)
+{
+	struct trace_iterator *iter = s->private;
+	struct trace_array *tr = iter->tr;
+
+	if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
+		return;
+
+	if (tr->trace_flags & TRACE_ITER_LATENCY_FMT) {
+		/* print nothing if the buffers are empty */
+		if (trace_empty(iter))
+			return;
+
+		print_trace_header(s, iter);
+	}
+
+	__print_graph_headers_flags(tr, s, flags);
+}
+
+void graph_trace_open(struct trace_iterator *iter)
+{
+	/* pid and depth on the last trace processed */
+	struct fgraph_data *data;
+	gfp_t gfpflags;
+	int cpu;
+
+	iter->private = NULL;
+
+	/* We can be called in atomic context via ftrace_dump() */
+	gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
+
+	data = kzalloc(sizeof(*data), gfpflags);
+	if (!data)
+		goto out_err;
+
+	data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags);
+	if (!data->cpu_data)
+		goto out_err_free;
+
+	for_each_possible_cpu(cpu) {
+		pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
+		int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
+		int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
+		int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
+
+		*pid = -1;
+		*depth = 0;
+		*ignore = 0;
+		*depth_irq = -1;
+	}
+
+	iter->private = data;
+
+	return;
+
+ out_err_free:
+	kfree(data);
+ out_err:
+	pr_warn("function graph tracer: not enough memory\n");
+}
+
+void graph_trace_close(struct trace_iterator *iter)
+{
+	struct fgraph_data *data = iter->private;
+
+	if (data) {
+		free_percpu(data->cpu_data);
+		kfree(data);
+	}
+}
+
+static int
+func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
+{
+	if (bit == TRACE_GRAPH_PRINT_IRQS)
+		ftrace_graph_skip_irqs = !set;
+
+	if (bit == TRACE_GRAPH_SLEEP_TIME)
+		ftrace_graph_sleep_time_control(set);
+
+	if (bit == TRACE_GRAPH_GRAPH_TIME)
+		ftrace_graph_graph_time_control(set);
+
+	return 0;
+}
+
+static struct trace_event_functions graph_functions = {
+	.trace		= print_graph_function_event,
+};
+
+static struct trace_event graph_trace_entry_event = {
+	.type		= TRACE_GRAPH_ENT,
+	.funcs		= &graph_functions,
+};
+
+static struct trace_event graph_trace_ret_event = {
+	.type		= TRACE_GRAPH_RET,
+	.funcs		= &graph_functions
+};
+
+static struct tracer graph_trace __tracer_data = {
+	.name		= "function_graph",
+	.update_thresh	= graph_trace_update_thresh,
+	.open		= graph_trace_open,
+	.pipe_open	= graph_trace_open,
+	.close		= graph_trace_close,
+	.pipe_close	= graph_trace_close,
+	.init		= graph_trace_init,
+	.reset		= graph_trace_reset,
+	.print_line	= print_graph_function,
+	.print_header	= print_graph_headers,
+	.flags		= &tracer_flags,
+	.set_flag	= func_graph_set_flag,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest	= trace_selftest_startup_function_graph,
+#endif
+};
+
+
+static ssize_t
+graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
+		  loff_t *ppos)
+{
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	fgraph_max_depth = val;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static ssize_t
+graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
+		 loff_t *ppos)
+{
+	char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
+	int n;
+
+	n = sprintf(buf, "%d\n", fgraph_max_depth);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
+}
+
+static const struct file_operations graph_depth_fops = {
+	.open		= tracing_open_generic,
+	.write		= graph_depth_write,
+	.read		= graph_depth_read,
+	.llseek		= generic_file_llseek,
+};
+
+static __init int init_graph_tracefs(void)
+{
+	int ret;
+
+	ret = tracing_init_dentry();
+	if (ret)
+		return 0;
+
+	trace_create_file("max_graph_depth", TRACE_MODE_WRITE, NULL,
+			  NULL, &graph_depth_fops);
+
+	return 0;
+}
+fs_initcall(init_graph_tracefs);
+
+static __init int init_graph_trace(void)
+{
+	max_bytes_for_cpu = snprintf(NULL, 0, "%u", nr_cpu_ids - 1);
+
+	if (!register_trace_event(&graph_trace_entry_event)) {
+		pr_warn("Warning: could not register graph trace events\n");
+		return 1;
+	}
+
+	if (!register_trace_event(&graph_trace_ret_event)) {
+		pr_warn("Warning: could not register graph trace events\n");
+		return 1;
+	}
+
+	return register_tracer(&graph_trace);
+}
+
+core_initcall(init_graph_trace);
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
new file mode 100644
index 000000000..b791524a6
--- /dev/null
+++ b/kernel/trace/trace_hwlat.c
@@ -0,0 +1,891 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_hwlat.c - A simple Hardware Latency detector.
+ *
+ * Use this tracer to detect large system latencies induced by the behavior of
+ * certain underlying system hardware or firmware, independent of Linux itself.
+ * The code was developed originally to detect the presence of SMIs on Intel
+ * and AMD systems, although there is no dependency upon x86 herein.
+ *
+ * The classical example usage of this tracer is in detecting the presence of
+ * SMIs or System Management Interrupts on Intel and AMD systems. An SMI is a
+ * somewhat special form of hardware interrupt spawned from earlier CPU debug
+ * modes in which the (BIOS/EFI/etc.) firmware arranges for the South Bridge
+ * LPC (or other device) to generate a special interrupt under certain
+ * circumstances, for example, upon expiration of a special SMI timer device,
+ * due to certain external thermal readings, on certain I/O address accesses,
+ * and other situations. An SMI hits a special CPU pin, triggers a special
+ * SMI mode (complete with special memory map), and the OS is unaware.
+ *
+ * Although certain hardware-inducing latencies are necessary (for example,
+ * a modern system often requires an SMI handler for correct thermal control
+ * and remote management) they can wreak havoc upon any OS-level performance
+ * guarantees toward low-latency, especially when the OS is not even made
+ * aware of the presence of these interrupts. For this reason, we need a
+ * somewhat brute force mechanism to detect these interrupts. In this case,
+ * we do it by hogging all of the CPU(s) for configurable timer intervals,
+ * sampling the built-in CPU timer, looking for discontiguous readings.
+ *
+ * WARNING: This implementation necessarily introduces latencies. Therefore,
+ *          you should NEVER use this tracer while running in a production
+ *          environment requiring any kind of low-latency performance
+ *          guarantee(s).
+ *
+ * Copyright (C) 2008-2009 Jon Masters, Red Hat, Inc. <jcm@redhat.com>
+ * Copyright (C) 2013-2016 Steven Rostedt, Red Hat, Inc. <srostedt@redhat.com>
+ *
+ * Includes useful feedback from Clark Williams <williams@redhat.com>
+ *
+ */
+#include <linux/kthread.h>
+#include <linux/tracefs.h>
+#include <linux/uaccess.h>
+#include <linux/cpumask.h>
+#include <linux/delay.h>
+#include <linux/sched/clock.h>
+#include "trace.h"
+
+static struct trace_array	*hwlat_trace;
+
+#define U64STR_SIZE		22			/* 20 digits max */
+
+#define BANNER			"hwlat_detector: "
+#define DEFAULT_SAMPLE_WINDOW	1000000			/* 1s */
+#define DEFAULT_SAMPLE_WIDTH	500000			/* 0.5s */
+#define DEFAULT_LAT_THRESHOLD	10			/* 10us */
+
+static struct dentry *hwlat_sample_width;	/* sample width us */
+static struct dentry *hwlat_sample_window;	/* sample window us */
+static struct dentry *hwlat_thread_mode;	/* hwlat thread mode */
+
+enum {
+	MODE_NONE = 0,
+	MODE_ROUND_ROBIN,
+	MODE_PER_CPU,
+	MODE_MAX
+};
+static char *thread_mode_str[] = { "none", "round-robin", "per-cpu" };
+
+/* Save the previous tracing_thresh value */
+static unsigned long save_tracing_thresh;
+
+/* runtime kthread data */
+struct hwlat_kthread_data {
+	struct task_struct	*kthread;
+	/* NMI timestamp counters */
+	u64			nmi_ts_start;
+	u64			nmi_total_ts;
+	int			nmi_count;
+	int			nmi_cpu;
+};
+
+static struct hwlat_kthread_data hwlat_single_cpu_data;
+static DEFINE_PER_CPU(struct hwlat_kthread_data, hwlat_per_cpu_data);
+
+/* Tells NMIs to call back to the hwlat tracer to record timestamps */
+bool trace_hwlat_callback_enabled;
+
+/* If the user changed threshold, remember it */
+static u64 last_tracing_thresh = DEFAULT_LAT_THRESHOLD * NSEC_PER_USEC;
+
+/* Individual latency samples are stored here when detected. */
+struct hwlat_sample {
+	u64			seqnum;		/* unique sequence */
+	u64			duration;	/* delta */
+	u64			outer_duration;	/* delta (outer loop) */
+	u64			nmi_total_ts;	/* Total time spent in NMIs */
+	struct timespec64	timestamp;	/* wall time */
+	int			nmi_count;	/* # NMIs during this sample */
+	int			count;		/* # of iterations over thresh */
+};
+
+/* keep the global state somewhere. */
+static struct hwlat_data {
+
+	struct mutex lock;		/* protect changes */
+
+	u64	count;			/* total since reset */
+
+	u64	sample_window;		/* total sampling window (on+off) */
+	u64	sample_width;		/* active sampling portion of window */
+
+	int	thread_mode;		/* thread mode */
+
+} hwlat_data = {
+	.sample_window		= DEFAULT_SAMPLE_WINDOW,
+	.sample_width		= DEFAULT_SAMPLE_WIDTH,
+	.thread_mode		= MODE_ROUND_ROBIN
+};
+
+static struct hwlat_kthread_data *get_cpu_data(void)
+{
+	if (hwlat_data.thread_mode == MODE_PER_CPU)
+		return this_cpu_ptr(&hwlat_per_cpu_data);
+	else
+		return &hwlat_single_cpu_data;
+}
+
+static bool hwlat_busy;
+
+static void trace_hwlat_sample(struct hwlat_sample *sample)
+{
+	struct trace_array *tr = hwlat_trace;
+	struct trace_event_call *call = &event_hwlat;
+	struct trace_buffer *buffer = tr->array_buffer.buffer;
+	struct ring_buffer_event *event;
+	struct hwlat_entry *entry;
+
+	event = trace_buffer_lock_reserve(buffer, TRACE_HWLAT, sizeof(*entry),
+					  tracing_gen_ctx());
+	if (!event)
+		return;
+	entry	= ring_buffer_event_data(event);
+	entry->seqnum			= sample->seqnum;
+	entry->duration			= sample->duration;
+	entry->outer_duration		= sample->outer_duration;
+	entry->timestamp		= sample->timestamp;
+	entry->nmi_total_ts		= sample->nmi_total_ts;
+	entry->nmi_count		= sample->nmi_count;
+	entry->count			= sample->count;
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit_nostack(buffer, event);
+}
+
+/* Macros to encapsulate the time capturing infrastructure */
+#define time_type	u64
+#define time_get()	trace_clock_local()
+#define time_to_us(x)	div_u64(x, 1000)
+#define time_sub(a, b)	((a) - (b))
+#define init_time(a, b)	(a = b)
+#define time_u64(a)	a
+
+void trace_hwlat_callback(bool enter)
+{
+	struct hwlat_kthread_data *kdata = get_cpu_data();
+
+	if (!kdata->kthread)
+		return;
+
+	/*
+	 * Currently trace_clock_local() calls sched_clock() and the
+	 * generic version is not NMI safe.
+	 */
+	if (!IS_ENABLED(CONFIG_GENERIC_SCHED_CLOCK)) {
+		if (enter)
+			kdata->nmi_ts_start = time_get();
+		else
+			kdata->nmi_total_ts += time_get() - kdata->nmi_ts_start;
+	}
+
+	if (enter)
+		kdata->nmi_count++;
+}
+
+/*
+ * hwlat_err - report a hwlat error.
+ */
+#define hwlat_err(msg) ({							\
+	struct trace_array *tr = hwlat_trace;					\
+										\
+	trace_array_printk_buf(tr->array_buffer.buffer, _THIS_IP_, msg);	\
+})
+
+/**
+ * get_sample - sample the CPU TSC and look for likely hardware latencies
+ *
+ * Used to repeatedly capture the CPU TSC (or similar), looking for potential
+ * hardware-induced latency. Called with interrupts disabled and with
+ * hwlat_data.lock held.
+ */
+static int get_sample(void)
+{
+	struct hwlat_kthread_data *kdata = get_cpu_data();
+	struct trace_array *tr = hwlat_trace;
+	struct hwlat_sample s;
+	time_type start, t1, t2, last_t2;
+	s64 diff, outer_diff, total, last_total = 0;
+	u64 sample = 0;
+	u64 thresh = tracing_thresh;
+	u64 outer_sample = 0;
+	int ret = -1;
+	unsigned int count = 0;
+
+	do_div(thresh, NSEC_PER_USEC); /* modifies interval value */
+
+	kdata->nmi_total_ts = 0;
+	kdata->nmi_count = 0;
+	/* Make sure NMIs see this first */
+	barrier();
+
+	trace_hwlat_callback_enabled = true;
+
+	init_time(last_t2, 0);
+	start = time_get(); /* start timestamp */
+	outer_diff = 0;
+
+	do {
+
+		t1 = time_get();	/* we'll look for a discontinuity */
+		t2 = time_get();
+
+		if (time_u64(last_t2)) {
+			/* Check the delta from outer loop (t2 to next t1) */
+			outer_diff = time_to_us(time_sub(t1, last_t2));
+			/* This shouldn't happen */
+			if (outer_diff < 0) {
+				hwlat_err(BANNER "time running backwards\n");
+				goto out;
+			}
+			if (outer_diff > outer_sample)
+				outer_sample = outer_diff;
+		}
+		last_t2 = t2;
+
+		total = time_to_us(time_sub(t2, start)); /* sample width */
+
+		/* Check for possible overflows */
+		if (total < last_total) {
+			hwlat_err("Time total overflowed\n");
+			break;
+		}
+		last_total = total;
+
+		/* This checks the inner loop (t1 to t2) */
+		diff = time_to_us(time_sub(t2, t1));     /* current diff */
+
+		if (diff > thresh || outer_diff > thresh) {
+			if (!count)
+				ktime_get_real_ts64(&s.timestamp);
+			count++;
+		}
+
+		/* This shouldn't happen */
+		if (diff < 0) {
+			hwlat_err(BANNER "time running backwards\n");
+			goto out;
+		}
+
+		if (diff > sample)
+			sample = diff; /* only want highest value */
+
+	} while (total <= hwlat_data.sample_width);
+
+	barrier(); /* finish the above in the view for NMIs */
+	trace_hwlat_callback_enabled = false;
+	barrier(); /* Make sure nmi_total_ts is no longer updated */
+
+	ret = 0;
+
+	/* If we exceed the threshold value, we have found a hardware latency */
+	if (sample > thresh || outer_sample > thresh) {
+		u64 latency;
+
+		ret = 1;
+
+		/* We read in microseconds */
+		if (kdata->nmi_total_ts)
+			do_div(kdata->nmi_total_ts, NSEC_PER_USEC);
+
+		hwlat_data.count++;
+		s.seqnum = hwlat_data.count;
+		s.duration = sample;
+		s.outer_duration = outer_sample;
+		s.nmi_total_ts = kdata->nmi_total_ts;
+		s.nmi_count = kdata->nmi_count;
+		s.count = count;
+		trace_hwlat_sample(&s);
+
+		latency = max(sample, outer_sample);
+
+		/* Keep a running maximum ever recorded hardware latency */
+		if (latency > tr->max_latency) {
+			tr->max_latency = latency;
+			latency_fsnotify(tr);
+		}
+	}
+
+out:
+	return ret;
+}
+
+static struct cpumask save_cpumask;
+
+static void move_to_next_cpu(void)
+{
+	struct cpumask *current_mask = &save_cpumask;
+	struct trace_array *tr = hwlat_trace;
+	int next_cpu;
+
+	/*
+	 * If for some reason the user modifies the CPU affinity
+	 * of this thread, then stop migrating for the duration
+	 * of the current test.
+	 */
+	if (!cpumask_equal(current_mask, current->cpus_ptr))
+		goto change_mode;
+
+	cpus_read_lock();
+	cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask);
+	next_cpu = cpumask_next(raw_smp_processor_id(), current_mask);
+	cpus_read_unlock();
+
+	if (next_cpu >= nr_cpu_ids)
+		next_cpu = cpumask_first(current_mask);
+
+	if (next_cpu >= nr_cpu_ids) /* Shouldn't happen! */
+		goto change_mode;
+
+	cpumask_clear(current_mask);
+	cpumask_set_cpu(next_cpu, current_mask);
+
+	set_cpus_allowed_ptr(current, current_mask);
+	return;
+
+ change_mode:
+	hwlat_data.thread_mode = MODE_NONE;
+	pr_info(BANNER "cpumask changed while in round-robin mode, switching to mode none\n");
+}
+
+/*
+ * kthread_fn - The CPU time sampling/hardware latency detection kernel thread
+ *
+ * Used to periodically sample the CPU TSC via a call to get_sample. We
+ * disable interrupts, which does (intentionally) introduce latency since we
+ * need to ensure nothing else might be running (and thus preempting).
+ * Obviously this should never be used in production environments.
+ *
+ * Executes one loop interaction on each CPU in tracing_cpumask sysfs file.
+ */
+static int kthread_fn(void *data)
+{
+	u64 interval;
+
+	while (!kthread_should_stop()) {
+
+		if (hwlat_data.thread_mode == MODE_ROUND_ROBIN)
+			move_to_next_cpu();
+
+		local_irq_disable();
+		get_sample();
+		local_irq_enable();
+
+		mutex_lock(&hwlat_data.lock);
+		interval = hwlat_data.sample_window - hwlat_data.sample_width;
+		mutex_unlock(&hwlat_data.lock);
+
+		do_div(interval, USEC_PER_MSEC); /* modifies interval value */
+
+		/* Always sleep for at least 1ms */
+		if (interval < 1)
+			interval = 1;
+
+		if (msleep_interruptible(interval))
+			break;
+	}
+
+	return 0;
+}
+
+/*
+ * stop_stop_kthread - Inform the hardware latency sampling/detector kthread to stop
+ *
+ * This kicks the running hardware latency sampling/detector kernel thread and
+ * tells it to stop sampling now. Use this on unload and at system shutdown.
+ */
+static void stop_single_kthread(void)
+{
+	struct hwlat_kthread_data *kdata = get_cpu_data();
+	struct task_struct *kthread;
+
+	cpus_read_lock();
+	kthread = kdata->kthread;
+
+	if (!kthread)
+		goto out_put_cpus;
+
+	kthread_stop(kthread);
+	kdata->kthread = NULL;
+
+out_put_cpus:
+	cpus_read_unlock();
+}
+
+
+/*
+ * start_single_kthread - Kick off the hardware latency sampling/detector kthread
+ *
+ * This starts the kernel thread that will sit and sample the CPU timestamp
+ * counter (TSC or similar) and look for potential hardware latencies.
+ */
+static int start_single_kthread(struct trace_array *tr)
+{
+	struct hwlat_kthread_data *kdata = get_cpu_data();
+	struct cpumask *current_mask = &save_cpumask;
+	struct task_struct *kthread;
+	int next_cpu;
+
+	cpus_read_lock();
+	if (kdata->kthread)
+		goto out_put_cpus;
+
+	kthread = kthread_create(kthread_fn, NULL, "hwlatd");
+	if (IS_ERR(kthread)) {
+		pr_err(BANNER "could not start sampling thread\n");
+		cpus_read_unlock();
+		return -ENOMEM;
+	}
+
+	/* Just pick the first CPU on first iteration */
+	cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask);
+
+	if (hwlat_data.thread_mode == MODE_ROUND_ROBIN) {
+		next_cpu = cpumask_first(current_mask);
+		cpumask_clear(current_mask);
+		cpumask_set_cpu(next_cpu, current_mask);
+
+	}
+
+	set_cpus_allowed_ptr(kthread, current_mask);
+
+	kdata->kthread = kthread;
+	wake_up_process(kthread);
+
+out_put_cpus:
+	cpus_read_unlock();
+	return 0;
+}
+
+/*
+ * stop_cpu_kthread - Stop a hwlat cpu kthread
+ */
+static void stop_cpu_kthread(unsigned int cpu)
+{
+	struct task_struct *kthread;
+
+	kthread = per_cpu(hwlat_per_cpu_data, cpu).kthread;
+	if (kthread)
+		kthread_stop(kthread);
+	per_cpu(hwlat_per_cpu_data, cpu).kthread = NULL;
+}
+
+/*
+ * stop_per_cpu_kthreads - Inform the hardware latency sampling/detector kthread to stop
+ *
+ * This kicks the running hardware latency sampling/detector kernel threads and
+ * tells it to stop sampling now. Use this on unload and at system shutdown.
+ */
+static void stop_per_cpu_kthreads(void)
+{
+	unsigned int cpu;
+
+	cpus_read_lock();
+	for_each_online_cpu(cpu)
+		stop_cpu_kthread(cpu);
+	cpus_read_unlock();
+}
+
+/*
+ * start_cpu_kthread - Start a hwlat cpu kthread
+ */
+static int start_cpu_kthread(unsigned int cpu)
+{
+	struct task_struct *kthread;
+
+	/* Do not start a new hwlatd thread if it is already running */
+	if (per_cpu(hwlat_per_cpu_data, cpu).kthread)
+		return 0;
+
+	kthread = kthread_run_on_cpu(kthread_fn, NULL, cpu, "hwlatd/%u");
+	if (IS_ERR(kthread)) {
+		pr_err(BANNER "could not start sampling thread\n");
+		return -ENOMEM;
+	}
+
+	per_cpu(hwlat_per_cpu_data, cpu).kthread = kthread;
+
+	return 0;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void hwlat_hotplug_workfn(struct work_struct *dummy)
+{
+	struct trace_array *tr = hwlat_trace;
+	unsigned int cpu = smp_processor_id();
+
+	mutex_lock(&trace_types_lock);
+	mutex_lock(&hwlat_data.lock);
+	cpus_read_lock();
+
+	if (!hwlat_busy || hwlat_data.thread_mode != MODE_PER_CPU)
+		goto out_unlock;
+
+	if (!cpumask_test_cpu(cpu, tr->tracing_cpumask))
+		goto out_unlock;
+
+	start_cpu_kthread(cpu);
+
+out_unlock:
+	cpus_read_unlock();
+	mutex_unlock(&hwlat_data.lock);
+	mutex_unlock(&trace_types_lock);
+}
+
+static DECLARE_WORK(hwlat_hotplug_work, hwlat_hotplug_workfn);
+
+/*
+ * hwlat_cpu_init - CPU hotplug online callback function
+ */
+static int hwlat_cpu_init(unsigned int cpu)
+{
+	schedule_work_on(cpu, &hwlat_hotplug_work);
+	return 0;
+}
+
+/*
+ * hwlat_cpu_die - CPU hotplug offline callback function
+ */
+static int hwlat_cpu_die(unsigned int cpu)
+{
+	stop_cpu_kthread(cpu);
+	return 0;
+}
+
+static void hwlat_init_hotplug_support(void)
+{
+	int ret;
+
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "trace/hwlat:online",
+				hwlat_cpu_init, hwlat_cpu_die);
+	if (ret < 0)
+		pr_warn(BANNER "Error to init cpu hotplug support\n");
+
+	return;
+}
+#else /* CONFIG_HOTPLUG_CPU */
+static void hwlat_init_hotplug_support(void)
+{
+	return;
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
+/*
+ * start_per_cpu_kthreads - Kick off the hardware latency sampling/detector kthreads
+ *
+ * This starts the kernel threads that will sit on potentially all cpus and
+ * sample the CPU timestamp counter (TSC or similar) and look for potential
+ * hardware latencies.
+ */
+static int start_per_cpu_kthreads(struct trace_array *tr)
+{
+	struct cpumask *current_mask = &save_cpumask;
+	unsigned int cpu;
+	int retval;
+
+	cpus_read_lock();
+	/*
+	 * Run only on CPUs in which hwlat is allowed to run.
+	 */
+	cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask);
+
+	for_each_cpu(cpu, current_mask) {
+		retval = start_cpu_kthread(cpu);
+		if (retval)
+			goto out_error;
+	}
+	cpus_read_unlock();
+
+	return 0;
+
+out_error:
+	cpus_read_unlock();
+	stop_per_cpu_kthreads();
+	return retval;
+}
+
+static void *s_mode_start(struct seq_file *s, loff_t *pos)
+{
+	int mode = *pos;
+
+	mutex_lock(&hwlat_data.lock);
+
+	if (mode >= MODE_MAX)
+		return NULL;
+
+	return pos;
+}
+
+static void *s_mode_next(struct seq_file *s, void *v, loff_t *pos)
+{
+	int mode = ++(*pos);
+
+	if (mode >= MODE_MAX)
+		return NULL;
+
+	return pos;
+}
+
+static int s_mode_show(struct seq_file *s, void *v)
+{
+	loff_t *pos = v;
+	int mode = *pos;
+
+	if (mode == hwlat_data.thread_mode)
+		seq_printf(s, "[%s]", thread_mode_str[mode]);
+	else
+		seq_printf(s, "%s", thread_mode_str[mode]);
+
+	if (mode < MODE_MAX - 1) /* if mode is any but last */
+		seq_puts(s, " ");
+
+	return 0;
+}
+
+static void s_mode_stop(struct seq_file *s, void *v)
+{
+	seq_puts(s, "\n");
+	mutex_unlock(&hwlat_data.lock);
+}
+
+static const struct seq_operations thread_mode_seq_ops = {
+	.start		= s_mode_start,
+	.next		= s_mode_next,
+	.show		= s_mode_show,
+	.stop		= s_mode_stop
+};
+
+static int hwlat_mode_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &thread_mode_seq_ops);
+};
+
+static void hwlat_tracer_start(struct trace_array *tr);
+static void hwlat_tracer_stop(struct trace_array *tr);
+
+/**
+ * hwlat_mode_write - Write function for "mode" entry
+ * @filp: The active open file structure
+ * @ubuf: The user buffer that contains the value to write
+ * @cnt: The maximum number of bytes to write to "file"
+ * @ppos: The current position in @file
+ *
+ * This function provides a write implementation for the "mode" interface
+ * to the hardware latency detector. hwlatd has different operation modes.
+ * The "none" sets the allowed cpumask for a single hwlatd thread at the
+ * startup and lets the scheduler handle the migration. The default mode is
+ * the "round-robin" one, in which a single hwlatd thread runs, migrating
+ * among the allowed CPUs in a round-robin fashion. The "per-cpu" mode
+ * creates one hwlatd thread per allowed CPU.
+ */
+static ssize_t hwlat_mode_write(struct file *filp, const char __user *ubuf,
+				 size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = hwlat_trace;
+	const char *mode;
+	char buf[64];
+	int ret, i;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	mode = strstrip(buf);
+
+	ret = -EINVAL;
+
+	/*
+	 * trace_types_lock is taken to avoid concurrency on start/stop
+	 * and hwlat_busy.
+	 */
+	mutex_lock(&trace_types_lock);
+	if (hwlat_busy)
+		hwlat_tracer_stop(tr);
+
+	mutex_lock(&hwlat_data.lock);
+
+	for (i = 0; i < MODE_MAX; i++) {
+		if (strcmp(mode, thread_mode_str[i]) == 0) {
+			hwlat_data.thread_mode = i;
+			ret = cnt;
+		}
+	}
+
+	mutex_unlock(&hwlat_data.lock);
+
+	if (hwlat_busy)
+		hwlat_tracer_start(tr);
+	mutex_unlock(&trace_types_lock);
+
+	*ppos += cnt;
+
+
+
+	return ret;
+}
+
+/*
+ * The width parameter is read/write using the generic trace_min_max_param
+ * method. The *val is protected by the hwlat_data lock and is upper
+ * bounded by the window parameter.
+ */
+static struct trace_min_max_param hwlat_width = {
+	.lock		= &hwlat_data.lock,
+	.val		= &hwlat_data.sample_width,
+	.max		= &hwlat_data.sample_window,
+	.min		= NULL,
+};
+
+/*
+ * The window parameter is read/write using the generic trace_min_max_param
+ * method. The *val is protected by the hwlat_data lock and is lower
+ * bounded by the width parameter.
+ */
+static struct trace_min_max_param hwlat_window = {
+	.lock		= &hwlat_data.lock,
+	.val		= &hwlat_data.sample_window,
+	.max		= NULL,
+	.min		= &hwlat_data.sample_width,
+};
+
+static const struct file_operations thread_mode_fops = {
+	.open		= hwlat_mode_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+	.write		= hwlat_mode_write
+};
+/**
+ * init_tracefs - A function to initialize the tracefs interface files
+ *
+ * This function creates entries in tracefs for "hwlat_detector".
+ * It creates the hwlat_detector directory in the tracing directory,
+ * and within that directory is the count, width and window files to
+ * change and view those values.
+ */
+static int init_tracefs(void)
+{
+	int ret;
+	struct dentry *top_dir;
+
+	ret = tracing_init_dentry();
+	if (ret)
+		return -ENOMEM;
+
+	top_dir = tracefs_create_dir("hwlat_detector", NULL);
+	if (!top_dir)
+		return -ENOMEM;
+
+	hwlat_sample_window = tracefs_create_file("window", TRACE_MODE_WRITE,
+						  top_dir,
+						  &hwlat_window,
+						  &trace_min_max_fops);
+	if (!hwlat_sample_window)
+		goto err;
+
+	hwlat_sample_width = tracefs_create_file("width", TRACE_MODE_WRITE,
+						 top_dir,
+						 &hwlat_width,
+						 &trace_min_max_fops);
+	if (!hwlat_sample_width)
+		goto err;
+
+	hwlat_thread_mode = trace_create_file("mode", TRACE_MODE_WRITE,
+					      top_dir,
+					      NULL,
+					      &thread_mode_fops);
+	if (!hwlat_thread_mode)
+		goto err;
+
+	return 0;
+
+ err:
+	tracefs_remove(top_dir);
+	return -ENOMEM;
+}
+
+static void hwlat_tracer_start(struct trace_array *tr)
+{
+	int err;
+
+	if (hwlat_data.thread_mode == MODE_PER_CPU)
+		err = start_per_cpu_kthreads(tr);
+	else
+		err = start_single_kthread(tr);
+	if (err)
+		pr_err(BANNER "Cannot start hwlat kthread\n");
+}
+
+static void hwlat_tracer_stop(struct trace_array *tr)
+{
+	if (hwlat_data.thread_mode == MODE_PER_CPU)
+		stop_per_cpu_kthreads();
+	else
+		stop_single_kthread();
+}
+
+static int hwlat_tracer_init(struct trace_array *tr)
+{
+	/* Only allow one instance to enable this */
+	if (hwlat_busy)
+		return -EBUSY;
+
+	hwlat_trace = tr;
+
+	hwlat_data.count = 0;
+	tr->max_latency = 0;
+	save_tracing_thresh = tracing_thresh;
+
+	/* tracing_thresh is in nsecs, we speak in usecs */
+	if (!tracing_thresh)
+		tracing_thresh = last_tracing_thresh;
+
+	if (tracer_tracing_is_on(tr))
+		hwlat_tracer_start(tr);
+
+	hwlat_busy = true;
+
+	return 0;
+}
+
+static void hwlat_tracer_reset(struct trace_array *tr)
+{
+	hwlat_tracer_stop(tr);
+
+	/* the tracing threshold is static between runs */
+	last_tracing_thresh = tracing_thresh;
+
+	tracing_thresh = save_tracing_thresh;
+	hwlat_busy = false;
+}
+
+static struct tracer hwlat_tracer __read_mostly =
+{
+	.name		= "hwlat",
+	.init		= hwlat_tracer_init,
+	.reset		= hwlat_tracer_reset,
+	.start		= hwlat_tracer_start,
+	.stop		= hwlat_tracer_stop,
+	.allow_instances = true,
+};
+
+__init static int init_hwlat_tracer(void)
+{
+	int ret;
+
+	mutex_init(&hwlat_data.lock);
+
+	ret = register_tracer(&hwlat_tracer);
+	if (ret)
+		return ret;
+
+	hwlat_init_hotplug_support();
+
+	init_tracefs();
+
+	return 0;
+}
+late_initcall(init_hwlat_tracer);
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
new file mode 100644
index 000000000..ba37f768e
--- /dev/null
+++ b/kernel/trace/trace_irqsoff.c
@@ -0,0 +1,752 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace irqs off critical timings
+ *
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ *
+ * From code in the latency_tracer, that is:
+ *
+ *  Copyright (C) 2004-2006 Ingo Molnar
+ *  Copyright (C) 2004 Nadia Yvette Chambers
+ */
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+#include <linux/kprobes.h>
+
+#include "trace.h"
+
+#include <trace/events/preemptirq.h>
+
+#if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER)
+static struct trace_array		*irqsoff_trace __read_mostly;
+static int				tracer_enabled __read_mostly;
+
+static DEFINE_PER_CPU(int, tracing_cpu);
+
+static DEFINE_RAW_SPINLOCK(max_trace_lock);
+
+enum {
+	TRACER_IRQS_OFF		= (1 << 1),
+	TRACER_PREEMPT_OFF	= (1 << 2),
+};
+
+static int trace_type __read_mostly;
+
+static int save_flags;
+
+static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
+static int start_irqsoff_tracer(struct trace_array *tr, int graph);
+
+#ifdef CONFIG_PREEMPT_TRACER
+static inline int
+preempt_trace(int pc)
+{
+	return ((trace_type & TRACER_PREEMPT_OFF) && pc);
+}
+#else
+# define preempt_trace(pc) (0)
+#endif
+
+#ifdef CONFIG_IRQSOFF_TRACER
+static inline int
+irq_trace(void)
+{
+	return ((trace_type & TRACER_IRQS_OFF) &&
+		irqs_disabled());
+}
+#else
+# define irq_trace() (0)
+#endif
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+static int irqsoff_display_graph(struct trace_array *tr, int set);
+# define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
+#else
+static inline int irqsoff_display_graph(struct trace_array *tr, int set)
+{
+	return -EINVAL;
+}
+# define is_graph(tr) false
+#endif
+
+/*
+ * Sequence count - we record it when starting a measurement and
+ * skip the latency if the sequence has changed - some other section
+ * did a maximum and could disturb our measurement with serial console
+ * printouts, etc. Truly coinciding maximum latencies should be rare
+ * and what happens together happens separately as well, so this doesn't
+ * decrease the validity of the maximum found:
+ */
+static __cacheline_aligned_in_smp	unsigned long max_sequence;
+
+#ifdef CONFIG_FUNCTION_TRACER
+/*
+ * Prologue for the preempt and irqs off function tracers.
+ *
+ * Returns 1 if it is OK to continue, and data->disabled is
+ *            incremented.
+ *         0 if the trace is to be ignored, and data->disabled
+ *            is kept the same.
+ *
+ * Note, this function is also used outside this ifdef but
+ *  inside the #ifdef of the function graph tracer below.
+ *  This is OK, since the function graph tracer is
+ *  dependent on the function tracer.
+ */
+static int func_prolog_dec(struct trace_array *tr,
+			   struct trace_array_cpu **data,
+			   unsigned long *flags)
+{
+	long disabled;
+	int cpu;
+
+	/*
+	 * Does not matter if we preempt. We test the flags
+	 * afterward, to see if irqs are disabled or not.
+	 * If we preempt and get a false positive, the flags
+	 * test will fail.
+	 */
+	cpu = raw_smp_processor_id();
+	if (likely(!per_cpu(tracing_cpu, cpu)))
+		return 0;
+
+	local_save_flags(*flags);
+	/*
+	 * Slight chance to get a false positive on tracing_cpu,
+	 * although I'm starting to think there isn't a chance.
+	 * Leave this for now just to be paranoid.
+	 */
+	if (!irqs_disabled_flags(*flags) && !preempt_count())
+		return 0;
+
+	*data = per_cpu_ptr(tr->array_buffer.data, cpu);
+	disabled = atomic_inc_return(&(*data)->disabled);
+
+	if (likely(disabled == 1))
+		return 1;
+
+	atomic_dec(&(*data)->disabled);
+
+	return 0;
+}
+
+/*
+ * irqsoff uses its own tracer function to keep the overhead down:
+ */
+static void
+irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip,
+		    struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	struct trace_array *tr = irqsoff_trace;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	unsigned int trace_ctx;
+
+	if (!func_prolog_dec(tr, &data, &flags))
+		return;
+
+	trace_ctx = tracing_gen_ctx_flags(flags);
+
+	trace_function(tr, ip, parent_ip, trace_ctx);
+
+	atomic_dec(&data->disabled);
+}
+#endif /* CONFIG_FUNCTION_TRACER */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+static int irqsoff_display_graph(struct trace_array *tr, int set)
+{
+	int cpu;
+
+	if (!(is_graph(tr) ^ set))
+		return 0;
+
+	stop_irqsoff_tracer(irqsoff_trace, !set);
+
+	for_each_possible_cpu(cpu)
+		per_cpu(tracing_cpu, cpu) = 0;
+
+	tr->max_latency = 0;
+	tracing_reset_online_cpus(&irqsoff_trace->array_buffer);
+
+	return start_irqsoff_tracer(irqsoff_trace, set);
+}
+
+static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
+{
+	struct trace_array *tr = irqsoff_trace;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	unsigned int trace_ctx;
+	int ret;
+
+	if (ftrace_graph_ignore_func(trace))
+		return 0;
+	/*
+	 * Do not trace a function if it's filtered by set_graph_notrace.
+	 * Make the index of ret stack negative to indicate that it should
+	 * ignore further functions.  But it needs its own ret stack entry
+	 * to recover the original index in order to continue tracing after
+	 * returning from the function.
+	 */
+	if (ftrace_graph_notrace_addr(trace->func))
+		return 1;
+
+	if (!func_prolog_dec(tr, &data, &flags))
+		return 0;
+
+	trace_ctx = tracing_gen_ctx_flags(flags);
+	ret = __trace_graph_entry(tr, trace, trace_ctx);
+	atomic_dec(&data->disabled);
+
+	return ret;
+}
+
+static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
+{
+	struct trace_array *tr = irqsoff_trace;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	unsigned int trace_ctx;
+
+	ftrace_graph_addr_finish(trace);
+
+	if (!func_prolog_dec(tr, &data, &flags))
+		return;
+
+	trace_ctx = tracing_gen_ctx_flags(flags);
+	__trace_graph_return(tr, trace, trace_ctx);
+	atomic_dec(&data->disabled);
+}
+
+static struct fgraph_ops fgraph_ops = {
+	.entryfunc		= &irqsoff_graph_entry,
+	.retfunc		= &irqsoff_graph_return,
+};
+
+static void irqsoff_trace_open(struct trace_iterator *iter)
+{
+	if (is_graph(iter->tr))
+		graph_trace_open(iter);
+	else
+		iter->private = NULL;
+}
+
+static void irqsoff_trace_close(struct trace_iterator *iter)
+{
+	if (iter->private)
+		graph_trace_close(iter);
+}
+
+#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
+			    TRACE_GRAPH_PRINT_PROC | \
+			    TRACE_GRAPH_PRINT_REL_TIME | \
+			    TRACE_GRAPH_PRINT_DURATION)
+
+static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
+{
+	/*
+	 * In graph mode call the graph tracer output function,
+	 * otherwise go with the TRACE_FN event handler
+	 */
+	if (is_graph(iter->tr))
+		return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
+
+	return TRACE_TYPE_UNHANDLED;
+}
+
+static void irqsoff_print_header(struct seq_file *s)
+{
+	struct trace_array *tr = irqsoff_trace;
+
+	if (is_graph(tr))
+		print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
+	else
+		trace_default_header(s);
+}
+
+static void
+__trace_function(struct trace_array *tr,
+		 unsigned long ip, unsigned long parent_ip,
+		 unsigned int trace_ctx)
+{
+	if (is_graph(tr))
+		trace_graph_function(tr, ip, parent_ip, trace_ctx);
+	else
+		trace_function(tr, ip, parent_ip, trace_ctx);
+}
+
+#else
+#define __trace_function trace_function
+
+static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
+{
+	return TRACE_TYPE_UNHANDLED;
+}
+
+static void irqsoff_trace_open(struct trace_iterator *iter) { }
+static void irqsoff_trace_close(struct trace_iterator *iter) { }
+
+#ifdef CONFIG_FUNCTION_TRACER
+static void irqsoff_print_header(struct seq_file *s)
+{
+	trace_default_header(s);
+}
+#else
+static void irqsoff_print_header(struct seq_file *s)
+{
+	trace_latency_header(s);
+}
+#endif /* CONFIG_FUNCTION_TRACER */
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+/*
+ * Should this new latency be reported/recorded?
+ */
+static bool report_latency(struct trace_array *tr, u64 delta)
+{
+	if (tracing_thresh) {
+		if (delta < tracing_thresh)
+			return false;
+	} else {
+		if (delta <= tr->max_latency)
+			return false;
+	}
+	return true;
+}
+
+static void
+check_critical_timing(struct trace_array *tr,
+		      struct trace_array_cpu *data,
+		      unsigned long parent_ip,
+		      int cpu)
+{
+	u64 T0, T1, delta;
+	unsigned long flags;
+	unsigned int trace_ctx;
+
+	T0 = data->preempt_timestamp;
+	T1 = ftrace_now(cpu);
+	delta = T1-T0;
+
+	trace_ctx = tracing_gen_ctx();
+
+	if (!report_latency(tr, delta))
+		goto out;
+
+	raw_spin_lock_irqsave(&max_trace_lock, flags);
+
+	/* check if we are still the max latency */
+	if (!report_latency(tr, delta))
+		goto out_unlock;
+
+	__trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx);
+	/* Skip 5 functions to get to the irq/preempt enable function */
+	__trace_stack(tr, trace_ctx, 5);
+
+	if (data->critical_sequence != max_sequence)
+		goto out_unlock;
+
+	data->critical_end = parent_ip;
+
+	if (likely(!is_tracing_stopped())) {
+		tr->max_latency = delta;
+		update_max_tr_single(tr, current, cpu);
+	}
+
+	max_sequence++;
+
+out_unlock:
+	raw_spin_unlock_irqrestore(&max_trace_lock, flags);
+
+out:
+	data->critical_sequence = max_sequence;
+	data->preempt_timestamp = ftrace_now(cpu);
+	__trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx);
+}
+
+static nokprobe_inline void
+start_critical_timing(unsigned long ip, unsigned long parent_ip)
+{
+	int cpu;
+	struct trace_array *tr = irqsoff_trace;
+	struct trace_array_cpu *data;
+
+	if (!tracer_enabled || !tracing_is_enabled())
+		return;
+
+	cpu = raw_smp_processor_id();
+
+	if (per_cpu(tracing_cpu, cpu))
+		return;
+
+	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+
+	if (unlikely(!data) || atomic_read(&data->disabled))
+		return;
+
+	atomic_inc(&data->disabled);
+
+	data->critical_sequence = max_sequence;
+	data->preempt_timestamp = ftrace_now(cpu);
+	data->critical_start = parent_ip ? : ip;
+
+	__trace_function(tr, ip, parent_ip, tracing_gen_ctx());
+
+	per_cpu(tracing_cpu, cpu) = 1;
+
+	atomic_dec(&data->disabled);
+}
+
+static nokprobe_inline void
+stop_critical_timing(unsigned long ip, unsigned long parent_ip)
+{
+	int cpu;
+	struct trace_array *tr = irqsoff_trace;
+	struct trace_array_cpu *data;
+	unsigned int trace_ctx;
+
+	cpu = raw_smp_processor_id();
+	/* Always clear the tracing cpu on stopping the trace */
+	if (unlikely(per_cpu(tracing_cpu, cpu)))
+		per_cpu(tracing_cpu, cpu) = 0;
+	else
+		return;
+
+	if (!tracer_enabled || !tracing_is_enabled())
+		return;
+
+	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+
+	if (unlikely(!data) ||
+	    !data->critical_start || atomic_read(&data->disabled))
+		return;
+
+	atomic_inc(&data->disabled);
+
+	trace_ctx = tracing_gen_ctx();
+	__trace_function(tr, ip, parent_ip, trace_ctx);
+	check_critical_timing(tr, data, parent_ip ? : ip, cpu);
+	data->critical_start = 0;
+	atomic_dec(&data->disabled);
+}
+
+/* start and stop critical timings used to for stoppage (in idle) */
+void start_critical_timings(void)
+{
+	if (preempt_trace(preempt_count()) || irq_trace())
+		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+}
+EXPORT_SYMBOL_GPL(start_critical_timings);
+NOKPROBE_SYMBOL(start_critical_timings);
+
+void stop_critical_timings(void)
+{
+	if (preempt_trace(preempt_count()) || irq_trace())
+		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+}
+EXPORT_SYMBOL_GPL(stop_critical_timings);
+NOKPROBE_SYMBOL(stop_critical_timings);
+
+#ifdef CONFIG_FUNCTION_TRACER
+static bool function_enabled;
+
+static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
+{
+	int ret;
+
+	/* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
+	if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
+		return 0;
+
+	if (graph)
+		ret = register_ftrace_graph(&fgraph_ops);
+	else
+		ret = register_ftrace_function(tr->ops);
+
+	if (!ret)
+		function_enabled = true;
+
+	return ret;
+}
+
+static void unregister_irqsoff_function(struct trace_array *tr, int graph)
+{
+	if (!function_enabled)
+		return;
+
+	if (graph)
+		unregister_ftrace_graph(&fgraph_ops);
+	else
+		unregister_ftrace_function(tr->ops);
+
+	function_enabled = false;
+}
+
+static int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
+{
+	if (!(mask & TRACE_ITER_FUNCTION))
+		return 0;
+
+	if (set)
+		register_irqsoff_function(tr, is_graph(tr), 1);
+	else
+		unregister_irqsoff_function(tr, is_graph(tr));
+	return 1;
+}
+#else
+static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
+{
+	return 0;
+}
+static void unregister_irqsoff_function(struct trace_array *tr, int graph) { }
+static inline int irqsoff_function_set(struct trace_array *tr, u32 mask, int set)
+{
+	return 0;
+}
+#endif /* CONFIG_FUNCTION_TRACER */
+
+static int irqsoff_flag_changed(struct trace_array *tr, u32 mask, int set)
+{
+	struct tracer *tracer = tr->current_trace;
+
+	if (irqsoff_function_set(tr, mask, set))
+		return 0;
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	if (mask & TRACE_ITER_DISPLAY_GRAPH)
+		return irqsoff_display_graph(tr, set);
+#endif
+
+	return trace_keep_overwrite(tracer, mask, set);
+}
+
+static int start_irqsoff_tracer(struct trace_array *tr, int graph)
+{
+	int ret;
+
+	ret = register_irqsoff_function(tr, graph, 0);
+
+	if (!ret && tracing_is_enabled())
+		tracer_enabled = 1;
+	else
+		tracer_enabled = 0;
+
+	return ret;
+}
+
+static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
+{
+	tracer_enabled = 0;
+
+	unregister_irqsoff_function(tr, graph);
+}
+
+static bool irqsoff_busy;
+
+static int __irqsoff_tracer_init(struct trace_array *tr)
+{
+	if (irqsoff_busy)
+		return -EBUSY;
+
+	save_flags = tr->trace_flags;
+
+	/* non overwrite screws up the latency tracers */
+	set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
+	set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
+	/* without pause, we will produce garbage if another latency occurs */
+	set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, 1);
+
+	tr->max_latency = 0;
+	irqsoff_trace = tr;
+	/* make sure that the tracer is visible */
+	smp_wmb();
+
+	ftrace_init_array_ops(tr, irqsoff_tracer_call);
+
+	/* Only toplevel instance supports graph tracing */
+	if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
+				      is_graph(tr))))
+		printk(KERN_ERR "failed to start irqsoff tracer\n");
+
+	irqsoff_busy = true;
+	return 0;
+}
+
+static void __irqsoff_tracer_reset(struct trace_array *tr)
+{
+	int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
+	int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
+	int pause_flag = save_flags & TRACE_ITER_PAUSE_ON_TRACE;
+
+	stop_irqsoff_tracer(tr, is_graph(tr));
+
+	set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
+	set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
+	set_tracer_flag(tr, TRACE_ITER_PAUSE_ON_TRACE, pause_flag);
+	ftrace_reset_array_ops(tr);
+
+	irqsoff_busy = false;
+}
+
+static void irqsoff_tracer_start(struct trace_array *tr)
+{
+	tracer_enabled = 1;
+}
+
+static void irqsoff_tracer_stop(struct trace_array *tr)
+{
+	tracer_enabled = 0;
+}
+
+#ifdef CONFIG_IRQSOFF_TRACER
+/*
+ * We are only interested in hardirq on/off events:
+ */
+void tracer_hardirqs_on(unsigned long a0, unsigned long a1)
+{
+	if (!preempt_trace(preempt_count()) && irq_trace())
+		stop_critical_timing(a0, a1);
+}
+NOKPROBE_SYMBOL(tracer_hardirqs_on);
+
+void tracer_hardirqs_off(unsigned long a0, unsigned long a1)
+{
+	if (!preempt_trace(preempt_count()) && irq_trace())
+		start_critical_timing(a0, a1);
+}
+NOKPROBE_SYMBOL(tracer_hardirqs_off);
+
+static int irqsoff_tracer_init(struct trace_array *tr)
+{
+	trace_type = TRACER_IRQS_OFF;
+
+	return __irqsoff_tracer_init(tr);
+}
+
+static void irqsoff_tracer_reset(struct trace_array *tr)
+{
+	__irqsoff_tracer_reset(tr);
+}
+
+static struct tracer irqsoff_tracer __read_mostly =
+{
+	.name		= "irqsoff",
+	.init		= irqsoff_tracer_init,
+	.reset		= irqsoff_tracer_reset,
+	.start		= irqsoff_tracer_start,
+	.stop		= irqsoff_tracer_stop,
+	.print_max	= true,
+	.print_header   = irqsoff_print_header,
+	.print_line     = irqsoff_print_line,
+	.flag_changed	= irqsoff_flag_changed,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest    = trace_selftest_startup_irqsoff,
+#endif
+	.open           = irqsoff_trace_open,
+	.close          = irqsoff_trace_close,
+	.allow_instances = true,
+	.use_max_tr	= true,
+};
+#endif /*  CONFIG_IRQSOFF_TRACER */
+
+#ifdef CONFIG_PREEMPT_TRACER
+void tracer_preempt_on(unsigned long a0, unsigned long a1)
+{
+	if (preempt_trace(preempt_count()) && !irq_trace())
+		stop_critical_timing(a0, a1);
+}
+
+void tracer_preempt_off(unsigned long a0, unsigned long a1)
+{
+	if (preempt_trace(preempt_count()) && !irq_trace())
+		start_critical_timing(a0, a1);
+}
+
+static int preemptoff_tracer_init(struct trace_array *tr)
+{
+	trace_type = TRACER_PREEMPT_OFF;
+
+	return __irqsoff_tracer_init(tr);
+}
+
+static void preemptoff_tracer_reset(struct trace_array *tr)
+{
+	__irqsoff_tracer_reset(tr);
+}
+
+static struct tracer preemptoff_tracer __read_mostly =
+{
+	.name		= "preemptoff",
+	.init		= preemptoff_tracer_init,
+	.reset		= preemptoff_tracer_reset,
+	.start		= irqsoff_tracer_start,
+	.stop		= irqsoff_tracer_stop,
+	.print_max	= true,
+	.print_header   = irqsoff_print_header,
+	.print_line     = irqsoff_print_line,
+	.flag_changed	= irqsoff_flag_changed,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest    = trace_selftest_startup_preemptoff,
+#endif
+	.open		= irqsoff_trace_open,
+	.close		= irqsoff_trace_close,
+	.allow_instances = true,
+	.use_max_tr	= true,
+};
+#endif /* CONFIG_PREEMPT_TRACER */
+
+#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
+
+static int preemptirqsoff_tracer_init(struct trace_array *tr)
+{
+	trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
+
+	return __irqsoff_tracer_init(tr);
+}
+
+static void preemptirqsoff_tracer_reset(struct trace_array *tr)
+{
+	__irqsoff_tracer_reset(tr);
+}
+
+static struct tracer preemptirqsoff_tracer __read_mostly =
+{
+	.name		= "preemptirqsoff",
+	.init		= preemptirqsoff_tracer_init,
+	.reset		= preemptirqsoff_tracer_reset,
+	.start		= irqsoff_tracer_start,
+	.stop		= irqsoff_tracer_stop,
+	.print_max	= true,
+	.print_header   = irqsoff_print_header,
+	.print_line     = irqsoff_print_line,
+	.flag_changed	= irqsoff_flag_changed,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest    = trace_selftest_startup_preemptirqsoff,
+#endif
+	.open		= irqsoff_trace_open,
+	.close		= irqsoff_trace_close,
+	.allow_instances = true,
+	.use_max_tr	= true,
+};
+#endif
+
+__init static int init_irqsoff_tracer(void)
+{
+#ifdef CONFIG_IRQSOFF_TRACER
+	register_tracer(&irqsoff_tracer);
+#endif
+#ifdef CONFIG_PREEMPT_TRACER
+	register_tracer(&preemptoff_tracer);
+#endif
+#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
+	register_tracer(&preemptirqsoff_tracer);
+#endif
+
+	return 0;
+}
+core_initcall(init_irqsoff_tracer);
+#endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */
diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c
new file mode 100644
index 000000000..59857a1ee
--- /dev/null
+++ b/kernel/trace/trace_kdb.c
@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kdb helper for dumping the ftrace buffer
+ *
+ * Copyright (C) 2010 Jason Wessel <jason.wessel@windriver.com>
+ *
+ * ftrace_dump_buf based on ftrace_dump:
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ *
+ */
+#include <linux/init.h>
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+#include <linux/ftrace.h>
+
+#include "trace.h"
+#include "trace_output.h"
+
+static struct trace_iterator iter;
+static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
+
+static void ftrace_dump_buf(int skip_entries, long cpu_file)
+{
+	struct trace_array *tr;
+	unsigned int old_userobj;
+	int cnt = 0, cpu;
+
+	tr = iter.tr;
+
+	old_userobj = tr->trace_flags;
+
+	/* don't look at user memory in panic mode */
+	tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
+
+	kdb_printf("Dumping ftrace buffer:\n");
+	if (skip_entries)
+		kdb_printf("(skipping %d entries)\n", skip_entries);
+
+	trace_iterator_reset(&iter);
+	iter.iter_flags |= TRACE_FILE_LAT_FMT;
+
+	if (cpu_file == RING_BUFFER_ALL_CPUS) {
+		for_each_tracing_cpu(cpu) {
+			iter.buffer_iter[cpu] =
+			ring_buffer_read_prepare(iter.array_buffer->buffer,
+						 cpu, GFP_ATOMIC);
+			ring_buffer_read_start(iter.buffer_iter[cpu]);
+			tracing_iter_reset(&iter, cpu);
+		}
+	} else {
+		iter.cpu_file = cpu_file;
+		iter.buffer_iter[cpu_file] =
+			ring_buffer_read_prepare(iter.array_buffer->buffer,
+						 cpu_file, GFP_ATOMIC);
+		ring_buffer_read_start(iter.buffer_iter[cpu_file]);
+		tracing_iter_reset(&iter, cpu_file);
+	}
+
+	while (trace_find_next_entry_inc(&iter)) {
+		if (!cnt)
+			kdb_printf("---------------------------------\n");
+		cnt++;
+
+		if (!skip_entries) {
+			print_trace_line(&iter);
+			trace_printk_seq(&iter.seq);
+		} else {
+			skip_entries--;
+		}
+
+		if (KDB_FLAG(CMD_INTERRUPT))
+			goto out;
+	}
+
+	if (!cnt)
+		kdb_printf("   (ftrace buffer empty)\n");
+	else
+		kdb_printf("---------------------------------\n");
+
+out:
+	tr->trace_flags = old_userobj;
+
+	for_each_tracing_cpu(cpu) {
+		if (iter.buffer_iter[cpu]) {
+			ring_buffer_read_finish(iter.buffer_iter[cpu]);
+			iter.buffer_iter[cpu] = NULL;
+		}
+	}
+}
+
+/*
+ * kdb_ftdump - Dump the ftrace log buffer
+ */
+static int kdb_ftdump(int argc, const char **argv)
+{
+	int skip_entries = 0;
+	long cpu_file;
+	char *cp;
+	int cnt;
+	int cpu;
+
+	if (argc > 2)
+		return KDB_ARGCOUNT;
+
+	if (argc) {
+		skip_entries = simple_strtol(argv[1], &cp, 0);
+		if (*cp)
+			skip_entries = 0;
+	}
+
+	if (argc == 2) {
+		cpu_file = simple_strtol(argv[2], &cp, 0);
+		if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 ||
+		    !cpu_online(cpu_file))
+			return KDB_BADINT;
+	} else {
+		cpu_file = RING_BUFFER_ALL_CPUS;
+	}
+
+	kdb_trap_printk++;
+
+	trace_init_global_iter(&iter);
+	iter.buffer_iter = buffer_iter;
+
+	for_each_tracing_cpu(cpu) {
+		atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
+	}
+
+	/* A negative skip_entries means skip all but the last entries */
+	if (skip_entries < 0) {
+		if (cpu_file == RING_BUFFER_ALL_CPUS)
+			cnt = trace_total_entries(NULL);
+		else
+			cnt = trace_total_entries_cpu(NULL, cpu_file);
+		skip_entries = max(cnt + skip_entries, 0);
+	}
+
+	ftrace_dump_buf(skip_entries, cpu_file);
+
+	for_each_tracing_cpu(cpu) {
+		atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
+	}
+
+	kdb_trap_printk--;
+
+	return 0;
+}
+
+static kdbtab_t ftdump_cmd = {
+	.name = "ftdump",
+	.func = kdb_ftdump,
+	.usage = "[skip_#entries] [cpu]",
+	.help = "Dump ftrace log; -skip dumps last #entries",
+	.flags = KDB_ENABLE_ALWAYS_SAFE,
+};
+
+static __init int kdb_ftrace_register(void)
+{
+	kdb_register(&ftdump_cmd);
+	return 0;
+}
+
+late_initcall(kdb_ftrace_register);
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
new file mode 100644
index 000000000..e3993d196
--- /dev/null
+++ b/kernel/trace/trace_kprobe.c
@@ -0,0 +1,2133 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Kprobes-based tracing events
+ *
+ * Created by Masami Hiramatsu <mhiramat@redhat.com>
+ *
+ */
+#define pr_fmt(fmt)	"trace_kprobe: " fmt
+
+#include <linux/bpf-cgroup.h>
+#include <linux/security.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/rculist.h>
+#include <linux/error-injection.h>
+
+#include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
+
+#include "trace_dynevent.h"
+#include "trace_kprobe_selftest.h"
+#include "trace_probe.h"
+#include "trace_probe_tmpl.h"
+#include "trace_probe_kernel.h"
+
+#define KPROBE_EVENT_SYSTEM "kprobes"
+#define KRETPROBE_MAXACTIVE_MAX 4096
+
+/* Kprobe early definition from command line */
+static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
+
+static int __init set_kprobe_boot_events(char *str)
+{
+	strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
+	disable_tracing_selftest("running kprobe events");
+
+	return 1;
+}
+__setup("kprobe_event=", set_kprobe_boot_events);
+
+static int trace_kprobe_create(const char *raw_command);
+static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
+static int trace_kprobe_release(struct dyn_event *ev);
+static bool trace_kprobe_is_busy(struct dyn_event *ev);
+static bool trace_kprobe_match(const char *system, const char *event,
+			int argc, const char **argv, struct dyn_event *ev);
+
+static struct dyn_event_operations trace_kprobe_ops = {
+	.create = trace_kprobe_create,
+	.show = trace_kprobe_show,
+	.is_busy = trace_kprobe_is_busy,
+	.free = trace_kprobe_release,
+	.match = trace_kprobe_match,
+};
+
+/*
+ * Kprobe event core functions
+ */
+struct trace_kprobe {
+	struct dyn_event	devent;
+	struct kretprobe	rp;	/* Use rp.kp for kprobe use */
+	unsigned long __percpu *nhit;
+	const char		*symbol;	/* symbol name */
+	struct trace_probe	tp;
+};
+
+static bool is_trace_kprobe(struct dyn_event *ev)
+{
+	return ev->ops == &trace_kprobe_ops;
+}
+
+static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
+{
+	return container_of(ev, struct trace_kprobe, devent);
+}
+
+/**
+ * for_each_trace_kprobe - iterate over the trace_kprobe list
+ * @pos:	the struct trace_kprobe * for each entry
+ * @dpos:	the struct dyn_event * to use as a loop cursor
+ */
+#define for_each_trace_kprobe(pos, dpos)	\
+	for_each_dyn_event(dpos)		\
+		if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
+
+static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
+{
+	return tk->rp.handler != NULL;
+}
+
+static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
+{
+	return tk->symbol ? tk->symbol : "unknown";
+}
+
+static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
+{
+	return tk->rp.kp.offset;
+}
+
+static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
+{
+	return kprobe_gone(&tk->rp.kp);
+}
+
+static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
+						 struct module *mod)
+{
+	int len = strlen(module_name(mod));
+	const char *name = trace_kprobe_symbol(tk);
+
+	return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
+}
+
+static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
+{
+	char *p;
+	bool ret;
+
+	if (!tk->symbol)
+		return false;
+	p = strchr(tk->symbol, ':');
+	if (!p)
+		return true;
+	*p = '\0';
+	rcu_read_lock_sched();
+	ret = !!find_module(tk->symbol);
+	rcu_read_unlock_sched();
+	*p = ':';
+
+	return ret;
+}
+
+static bool trace_kprobe_is_busy(struct dyn_event *ev)
+{
+	struct trace_kprobe *tk = to_trace_kprobe(ev);
+
+	return trace_probe_is_enabled(&tk->tp);
+}
+
+static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
+					    int argc, const char **argv)
+{
+	char buf[MAX_ARGSTR_LEN + 1];
+
+	if (!argc)
+		return true;
+
+	if (!tk->symbol)
+		snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
+	else if (tk->rp.kp.offset)
+		snprintf(buf, sizeof(buf), "%s+%u",
+			 trace_kprobe_symbol(tk), tk->rp.kp.offset);
+	else
+		snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
+	if (strcmp(buf, argv[0]))
+		return false;
+	argc--; argv++;
+
+	return trace_probe_match_command_args(&tk->tp, argc, argv);
+}
+
+static bool trace_kprobe_match(const char *system, const char *event,
+			int argc, const char **argv, struct dyn_event *ev)
+{
+	struct trace_kprobe *tk = to_trace_kprobe(ev);
+
+	return (event[0] == '\0' ||
+		strcmp(trace_probe_name(&tk->tp), event) == 0) &&
+	    (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
+	    trace_kprobe_match_command_head(tk, argc, argv);
+}
+
+static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
+{
+	unsigned long nhit = 0;
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		nhit += *per_cpu_ptr(tk->nhit, cpu);
+
+	return nhit;
+}
+
+static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
+{
+	return !(list_empty(&tk->rp.kp.list) &&
+		 hlist_unhashed(&tk->rp.kp.hlist));
+}
+
+/* Return 0 if it fails to find the symbol address */
+static nokprobe_inline
+unsigned long trace_kprobe_address(struct trace_kprobe *tk)
+{
+	unsigned long addr;
+
+	if (tk->symbol) {
+		addr = (unsigned long)
+			kallsyms_lookup_name(trace_kprobe_symbol(tk));
+		if (addr)
+			addr += tk->rp.kp.offset;
+	} else {
+		addr = (unsigned long)tk->rp.kp.addr;
+	}
+	return addr;
+}
+
+static nokprobe_inline struct trace_kprobe *
+trace_kprobe_primary_from_call(struct trace_event_call *call)
+{
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return NULL;
+
+	return container_of(tp, struct trace_kprobe, tp);
+}
+
+bool trace_kprobe_on_func_entry(struct trace_event_call *call)
+{
+	struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
+
+	return tk ? (kprobe_on_func_entry(tk->rp.kp.addr,
+			tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
+			tk->rp.kp.addr ? 0 : tk->rp.kp.offset) == 0) : false;
+}
+
+bool trace_kprobe_error_injectable(struct trace_event_call *call)
+{
+	struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
+
+	return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
+	       false;
+}
+
+static int register_kprobe_event(struct trace_kprobe *tk);
+static int unregister_kprobe_event(struct trace_kprobe *tk);
+
+static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
+static int kretprobe_dispatcher(struct kretprobe_instance *ri,
+				struct pt_regs *regs);
+
+static void free_trace_kprobe(struct trace_kprobe *tk)
+{
+	if (tk) {
+		trace_probe_cleanup(&tk->tp);
+		kfree(tk->symbol);
+		free_percpu(tk->nhit);
+		kfree(tk);
+	}
+}
+
+/*
+ * Allocate new trace_probe and initialize it (including kprobes).
+ */
+static struct trace_kprobe *alloc_trace_kprobe(const char *group,
+					     const char *event,
+					     void *addr,
+					     const char *symbol,
+					     unsigned long offs,
+					     int maxactive,
+					     int nargs, bool is_return)
+{
+	struct trace_kprobe *tk;
+	int ret = -ENOMEM;
+
+	tk = kzalloc(struct_size(tk, tp.args, nargs), GFP_KERNEL);
+	if (!tk)
+		return ERR_PTR(ret);
+
+	tk->nhit = alloc_percpu(unsigned long);
+	if (!tk->nhit)
+		goto error;
+
+	if (symbol) {
+		tk->symbol = kstrdup(symbol, GFP_KERNEL);
+		if (!tk->symbol)
+			goto error;
+		tk->rp.kp.symbol_name = tk->symbol;
+		tk->rp.kp.offset = offs;
+	} else
+		tk->rp.kp.addr = addr;
+
+	if (is_return)
+		tk->rp.handler = kretprobe_dispatcher;
+	else
+		tk->rp.kp.pre_handler = kprobe_dispatcher;
+
+	tk->rp.maxactive = maxactive;
+	INIT_HLIST_NODE(&tk->rp.kp.hlist);
+	INIT_LIST_HEAD(&tk->rp.kp.list);
+
+	ret = trace_probe_init(&tk->tp, event, group, false);
+	if (ret < 0)
+		goto error;
+
+	dyn_event_init(&tk->devent, &trace_kprobe_ops);
+	return tk;
+error:
+	free_trace_kprobe(tk);
+	return ERR_PTR(ret);
+}
+
+static struct trace_kprobe *find_trace_kprobe(const char *event,
+					      const char *group)
+{
+	struct dyn_event *pos;
+	struct trace_kprobe *tk;
+
+	for_each_trace_kprobe(tk, pos)
+		if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
+		    strcmp(trace_probe_group_name(&tk->tp), group) == 0)
+			return tk;
+	return NULL;
+}
+
+static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
+{
+	int ret = 0;
+
+	if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
+		if (trace_kprobe_is_return(tk))
+			ret = enable_kretprobe(&tk->rp);
+		else
+			ret = enable_kprobe(&tk->rp.kp);
+	}
+
+	return ret;
+}
+
+static void __disable_trace_kprobe(struct trace_probe *tp)
+{
+	struct trace_kprobe *tk;
+
+	list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
+		if (!trace_kprobe_is_registered(tk))
+			continue;
+		if (trace_kprobe_is_return(tk))
+			disable_kretprobe(&tk->rp);
+		else
+			disable_kprobe(&tk->rp.kp);
+	}
+}
+
+/*
+ * Enable trace_probe
+ * if the file is NULL, enable "perf" handler, or enable "trace" handler.
+ */
+static int enable_trace_kprobe(struct trace_event_call *call,
+				struct trace_event_file *file)
+{
+	struct trace_probe *tp;
+	struct trace_kprobe *tk;
+	bool enabled;
+	int ret = 0;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENODEV;
+	enabled = trace_probe_is_enabled(tp);
+
+	/* This also changes "enabled" state */
+	if (file) {
+		ret = trace_probe_add_file(tp, file);
+		if (ret)
+			return ret;
+	} else
+		trace_probe_set_flag(tp, TP_FLAG_PROFILE);
+
+	if (enabled)
+		return 0;
+
+	list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
+		if (trace_kprobe_has_gone(tk))
+			continue;
+		ret = __enable_trace_kprobe(tk);
+		if (ret)
+			break;
+		enabled = true;
+	}
+
+	if (ret) {
+		/* Failed to enable one of them. Roll back all */
+		if (enabled)
+			__disable_trace_kprobe(tp);
+		if (file)
+			trace_probe_remove_file(tp, file);
+		else
+			trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
+	}
+
+	return ret;
+}
+
+/*
+ * Disable trace_probe
+ * if the file is NULL, disable "perf" handler, or disable "trace" handler.
+ */
+static int disable_trace_kprobe(struct trace_event_call *call,
+				struct trace_event_file *file)
+{
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENODEV;
+
+	if (file) {
+		if (!trace_probe_get_file_link(tp, file))
+			return -ENOENT;
+		if (!trace_probe_has_single_file(tp))
+			goto out;
+		trace_probe_clear_flag(tp, TP_FLAG_TRACE);
+	} else
+		trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
+
+	if (!trace_probe_is_enabled(tp))
+		__disable_trace_kprobe(tp);
+
+ out:
+	if (file)
+		/*
+		 * Synchronization is done in below function. For perf event,
+		 * file == NULL and perf_trace_event_unreg() calls
+		 * tracepoint_synchronize_unregister() to ensure synchronize
+		 * event. We don't need to care about it.
+		 */
+		trace_probe_remove_file(tp, file);
+
+	return 0;
+}
+
+#if defined(CONFIG_DYNAMIC_FTRACE) && \
+	!defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
+static bool __within_notrace_func(unsigned long addr)
+{
+	unsigned long offset, size;
+
+	if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
+		return false;
+
+	/* Get the entry address of the target function */
+	addr -= offset;
+
+	/*
+	 * Since ftrace_location_range() does inclusive range check, we need
+	 * to subtract 1 byte from the end address.
+	 */
+	return !ftrace_location_range(addr, addr + size - 1);
+}
+
+static bool within_notrace_func(struct trace_kprobe *tk)
+{
+	unsigned long addr = trace_kprobe_address(tk);
+	char symname[KSYM_NAME_LEN], *p;
+
+	if (!__within_notrace_func(addr))
+		return false;
+
+	/* Check if the address is on a suffixed-symbol */
+	if (!lookup_symbol_name(addr, symname)) {
+		p = strchr(symname, '.');
+		if (!p)
+			return true;
+		*p = '\0';
+		addr = (unsigned long)kprobe_lookup_name(symname, 0);
+		if (addr)
+			return __within_notrace_func(addr);
+	}
+
+	return true;
+}
+#else
+#define within_notrace_func(tk)	(false)
+#endif
+
+/* Internal register function - just handle k*probes and flags */
+static int __register_trace_kprobe(struct trace_kprobe *tk)
+{
+	int i, ret;
+
+	ret = security_locked_down(LOCKDOWN_KPROBES);
+	if (ret)
+		return ret;
+
+	if (trace_kprobe_is_registered(tk))
+		return -EINVAL;
+
+	if (within_notrace_func(tk)) {
+		pr_warn("Could not probe notrace function %s\n",
+			trace_kprobe_symbol(tk));
+		return -EINVAL;
+	}
+
+	for (i = 0; i < tk->tp.nr_args; i++) {
+		ret = traceprobe_update_arg(&tk->tp.args[i]);
+		if (ret)
+			return ret;
+	}
+
+	/* Set/clear disabled flag according to tp->flag */
+	if (trace_probe_is_enabled(&tk->tp))
+		tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
+	else
+		tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
+
+	if (trace_kprobe_is_return(tk))
+		ret = register_kretprobe(&tk->rp);
+	else
+		ret = register_kprobe(&tk->rp.kp);
+
+	return ret;
+}
+
+/* Internal unregister function - just handle k*probes and flags */
+static void __unregister_trace_kprobe(struct trace_kprobe *tk)
+{
+	if (trace_kprobe_is_registered(tk)) {
+		if (trace_kprobe_is_return(tk))
+			unregister_kretprobe(&tk->rp);
+		else
+			unregister_kprobe(&tk->rp.kp);
+		/* Cleanup kprobe for reuse and mark it unregistered */
+		INIT_HLIST_NODE(&tk->rp.kp.hlist);
+		INIT_LIST_HEAD(&tk->rp.kp.list);
+		if (tk->rp.kp.symbol_name)
+			tk->rp.kp.addr = NULL;
+	}
+}
+
+/* Unregister a trace_probe and probe_event */
+static int unregister_trace_kprobe(struct trace_kprobe *tk)
+{
+	/* If other probes are on the event, just unregister kprobe */
+	if (trace_probe_has_sibling(&tk->tp))
+		goto unreg;
+
+	/* Enabled event can not be unregistered */
+	if (trace_probe_is_enabled(&tk->tp))
+		return -EBUSY;
+
+	/* If there's a reference to the dynamic event */
+	if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp)))
+		return -EBUSY;
+
+	/* Will fail if probe is being used by ftrace or perf */
+	if (unregister_kprobe_event(tk))
+		return -EBUSY;
+
+unreg:
+	__unregister_trace_kprobe(tk);
+	dyn_event_remove(&tk->devent);
+	trace_probe_unlink(&tk->tp);
+
+	return 0;
+}
+
+static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
+					 struct trace_kprobe *comp)
+{
+	struct trace_probe_event *tpe = orig->tp.event;
+	int i;
+
+	list_for_each_entry(orig, &tpe->probes, tp.list) {
+		if (strcmp(trace_kprobe_symbol(orig),
+			   trace_kprobe_symbol(comp)) ||
+		    trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
+			continue;
+
+		/*
+		 * trace_probe_compare_arg_type() ensured that nr_args and
+		 * each argument name and type are same. Let's compare comm.
+		 */
+		for (i = 0; i < orig->tp.nr_args; i++) {
+			if (strcmp(orig->tp.args[i].comm,
+				   comp->tp.args[i].comm))
+				break;
+		}
+
+		if (i == orig->tp.nr_args)
+			return true;
+	}
+
+	return false;
+}
+
+static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
+{
+	int ret;
+
+	ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
+	if (ret) {
+		/* Note that argument starts index = 2 */
+		trace_probe_log_set_index(ret + 1);
+		trace_probe_log_err(0, DIFF_ARG_TYPE);
+		return -EEXIST;
+	}
+	if (trace_kprobe_has_same_kprobe(to, tk)) {
+		trace_probe_log_set_index(0);
+		trace_probe_log_err(0, SAME_PROBE);
+		return -EEXIST;
+	}
+
+	/* Append to existing event */
+	ret = trace_probe_append(&tk->tp, &to->tp);
+	if (ret)
+		return ret;
+
+	/* Register k*probe */
+	ret = __register_trace_kprobe(tk);
+	if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
+		pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
+		ret = 0;
+	}
+
+	if (ret)
+		trace_probe_unlink(&tk->tp);
+	else
+		dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
+
+	return ret;
+}
+
+/* Register a trace_probe and probe_event */
+static int register_trace_kprobe(struct trace_kprobe *tk)
+{
+	struct trace_kprobe *old_tk;
+	int ret;
+
+	mutex_lock(&event_mutex);
+
+	old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
+				   trace_probe_group_name(&tk->tp));
+	if (old_tk) {
+		if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
+			trace_probe_log_set_index(0);
+			trace_probe_log_err(0, DIFF_PROBE_TYPE);
+			ret = -EEXIST;
+		} else {
+			ret = append_trace_kprobe(tk, old_tk);
+		}
+		goto end;
+	}
+
+	/* Register new event */
+	ret = register_kprobe_event(tk);
+	if (ret) {
+		if (ret == -EEXIST) {
+			trace_probe_log_set_index(0);
+			trace_probe_log_err(0, EVENT_EXIST);
+		} else
+			pr_warn("Failed to register probe event(%d)\n", ret);
+		goto end;
+	}
+
+	/* Register k*probe */
+	ret = __register_trace_kprobe(tk);
+	if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
+		pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
+		ret = 0;
+	}
+
+	if (ret < 0)
+		unregister_kprobe_event(tk);
+	else
+		dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
+
+end:
+	mutex_unlock(&event_mutex);
+	return ret;
+}
+
+/* Module notifier call back, checking event on the module */
+static int trace_kprobe_module_callback(struct notifier_block *nb,
+				       unsigned long val, void *data)
+{
+	struct module *mod = data;
+	struct dyn_event *pos;
+	struct trace_kprobe *tk;
+	int ret;
+
+	if (val != MODULE_STATE_COMING)
+		return NOTIFY_DONE;
+
+	/* Update probes on coming module */
+	mutex_lock(&event_mutex);
+	for_each_trace_kprobe(tk, pos) {
+		if (trace_kprobe_within_module(tk, mod)) {
+			/* Don't need to check busy - this should have gone. */
+			__unregister_trace_kprobe(tk);
+			ret = __register_trace_kprobe(tk);
+			if (ret)
+				pr_warn("Failed to re-register probe %s on %s: %d\n",
+					trace_probe_name(&tk->tp),
+					module_name(mod), ret);
+		}
+	}
+	mutex_unlock(&event_mutex);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block trace_kprobe_module_nb = {
+	.notifier_call = trace_kprobe_module_callback,
+	.priority = 1	/* Invoked after kprobe module callback */
+};
+
+static int count_symbols(void *data, unsigned long unused)
+{
+	unsigned int *count = data;
+
+	(*count)++;
+
+	return 0;
+}
+
+struct sym_count_ctx {
+	unsigned int count;
+	const char *name;
+};
+
+static int count_mod_symbols(void *data, const char *name,
+			     struct module *module, unsigned long unused)
+{
+	struct sym_count_ctx *ctx = data;
+
+	if (strcmp(name, ctx->name) == 0)
+		ctx->count++;
+
+	return 0;
+}
+
+static unsigned int number_of_same_symbols(char *func_name)
+{
+	struct sym_count_ctx ctx = { .count = 0, .name = func_name };
+
+	kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count);
+
+	module_kallsyms_on_each_symbol(count_mod_symbols, &ctx);
+
+	return ctx.count;
+}
+
+static int __trace_kprobe_create(int argc, const char *argv[])
+{
+	/*
+	 * Argument syntax:
+	 *  - Add kprobe:
+	 *      p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
+	 *  - Add kretprobe:
+	 *      r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
+	 *    Or
+	 *      p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
+	 *
+	 * Fetch args:
+	 *  $retval	: fetch return value
+	 *  $stack	: fetch stack address
+	 *  $stackN	: fetch Nth of stack (N:0-)
+	 *  $comm       : fetch current task comm
+	 *  @ADDR	: fetch memory at ADDR (ADDR should be in kernel)
+	 *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
+	 *  %REG	: fetch register REG
+	 * Dereferencing memory fetch:
+	 *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
+	 * Alias name of args:
+	 *  NAME=FETCHARG : set NAME as alias of FETCHARG.
+	 * Type of args:
+	 *  FETCHARG:TYPE : use TYPE instead of unsigned long.
+	 */
+	struct trace_kprobe *tk = NULL;
+	int i, len, ret = 0;
+	bool is_return = false;
+	char *symbol = NULL, *tmp = NULL;
+	const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
+	enum probe_print_type ptype;
+	int maxactive = 0;
+	long offset = 0;
+	void *addr = NULL;
+	char buf[MAX_EVENT_NAME_LEN];
+	char gbuf[MAX_EVENT_NAME_LEN];
+	unsigned int flags = TPARG_FL_KERNEL;
+
+	switch (argv[0][0]) {
+	case 'r':
+		is_return = true;
+		break;
+	case 'p':
+		break;
+	default:
+		return -ECANCELED;
+	}
+	if (argc < 2)
+		return -ECANCELED;
+
+	trace_probe_log_init("trace_kprobe", argc, argv);
+
+	event = strchr(&argv[0][1], ':');
+	if (event)
+		event++;
+
+	if (isdigit(argv[0][1])) {
+		if (!is_return) {
+			trace_probe_log_err(1, MAXACT_NO_KPROBE);
+			goto parse_error;
+		}
+		if (event)
+			len = event - &argv[0][1] - 1;
+		else
+			len = strlen(&argv[0][1]);
+		if (len > MAX_EVENT_NAME_LEN - 1) {
+			trace_probe_log_err(1, BAD_MAXACT);
+			goto parse_error;
+		}
+		memcpy(buf, &argv[0][1], len);
+		buf[len] = '\0';
+		ret = kstrtouint(buf, 0, &maxactive);
+		if (ret || !maxactive) {
+			trace_probe_log_err(1, BAD_MAXACT);
+			goto parse_error;
+		}
+		/* kretprobes instances are iterated over via a list. The
+		 * maximum should stay reasonable.
+		 */
+		if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
+			trace_probe_log_err(1, MAXACT_TOO_BIG);
+			goto parse_error;
+		}
+	}
+
+	/* try to parse an address. if that fails, try to read the
+	 * input as a symbol. */
+	if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
+		trace_probe_log_set_index(1);
+		/* Check whether uprobe event specified */
+		if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
+			ret = -ECANCELED;
+			goto error;
+		}
+		/* a symbol specified */
+		symbol = kstrdup(argv[1], GFP_KERNEL);
+		if (!symbol)
+			return -ENOMEM;
+
+		tmp = strchr(symbol, '%');
+		if (tmp) {
+			if (!strcmp(tmp, "%return")) {
+				*tmp = '\0';
+				is_return = true;
+			} else {
+				trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
+				goto parse_error;
+			}
+		}
+
+		/* TODO: support .init module functions */
+		ret = traceprobe_split_symbol_offset(symbol, &offset);
+		if (ret || offset < 0 || offset > UINT_MAX) {
+			trace_probe_log_err(0, BAD_PROBE_ADDR);
+			goto parse_error;
+		}
+		if (is_return)
+			flags |= TPARG_FL_RETURN;
+		ret = kprobe_on_func_entry(NULL, symbol, offset);
+		if (ret == 0)
+			flags |= TPARG_FL_FENTRY;
+		/* Defer the ENOENT case until register kprobe */
+		if (ret == -EINVAL && is_return) {
+			trace_probe_log_err(0, BAD_RETPROBE);
+			goto parse_error;
+		}
+	}
+
+	if (symbol && !strchr(symbol, ':')) {
+		unsigned int count;
+
+		count = number_of_same_symbols(symbol);
+		if (count > 1) {
+			/*
+			 * Users should use ADDR to remove the ambiguity of
+			 * using KSYM only.
+			 */
+			trace_probe_log_err(0, NON_UNIQ_SYMBOL);
+			ret = -EADDRNOTAVAIL;
+
+			goto error;
+		} else if (count == 0) {
+			/*
+			 * We can return ENOENT earlier than when register the
+			 * kprobe.
+			 */
+			trace_probe_log_err(0, BAD_PROBE_ADDR);
+			ret = -ENOENT;
+
+			goto error;
+		}
+	}
+
+	trace_probe_log_set_index(0);
+	if (event) {
+		ret = traceprobe_parse_event_name(&event, &group, gbuf,
+						  event - argv[0]);
+		if (ret)
+			goto parse_error;
+	}
+
+	if (!event) {
+		/* Make a new event name */
+		if (symbol)
+			snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
+				 is_return ? 'r' : 'p', symbol, offset);
+		else
+			snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
+				 is_return ? 'r' : 'p', addr);
+		sanitize_event_name(buf);
+		event = buf;
+	}
+
+	/* setup a probe */
+	tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
+			       argc - 2, is_return);
+	if (IS_ERR(tk)) {
+		ret = PTR_ERR(tk);
+		/* This must return -ENOMEM, else there is a bug */
+		WARN_ON_ONCE(ret != -ENOMEM);
+		goto out;	/* We know tk is not allocated */
+	}
+	argc -= 2; argv += 2;
+
+	/* parse arguments */
+	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
+		trace_probe_log_set_index(i + 2);
+		ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], flags);
+		if (ret)
+			goto error;	/* This can be -ENOMEM */
+	}
+
+	ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
+	ret = traceprobe_set_print_fmt(&tk->tp, ptype);
+	if (ret < 0)
+		goto error;
+
+	ret = register_trace_kprobe(tk);
+	if (ret) {
+		trace_probe_log_set_index(1);
+		if (ret == -EILSEQ)
+			trace_probe_log_err(0, BAD_INSN_BNDRY);
+		else if (ret == -ENOENT)
+			trace_probe_log_err(0, BAD_PROBE_ADDR);
+		else if (ret != -ENOMEM && ret != -EEXIST)
+			trace_probe_log_err(0, FAIL_REG_PROBE);
+		goto error;
+	}
+
+out:
+	trace_probe_log_clear();
+	kfree(symbol);
+	return ret;
+
+parse_error:
+	ret = -EINVAL;
+error:
+	free_trace_kprobe(tk);
+	goto out;
+}
+
+static int trace_kprobe_create(const char *raw_command)
+{
+	return trace_probe_create(raw_command, __trace_kprobe_create);
+}
+
+static int create_or_delete_trace_kprobe(const char *raw_command)
+{
+	int ret;
+
+	if (raw_command[0] == '-')
+		return dyn_event_release(raw_command, &trace_kprobe_ops);
+
+	ret = trace_kprobe_create(raw_command);
+	return ret == -ECANCELED ? -EINVAL : ret;
+}
+
+static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
+{
+	return create_or_delete_trace_kprobe(cmd->seq.buffer);
+}
+
+/**
+ * kprobe_event_cmd_init - Initialize a kprobe event command object
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event
+ * @buf: A pointer to the buffer used to build the command
+ * @maxlen: The length of the buffer passed in @buf
+ *
+ * Initialize a synthetic event command object.  Use this before
+ * calling any of the other kprobe_event functions.
+ */
+void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
+{
+	dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
+			  trace_kprobe_run_command);
+}
+EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
+
+/**
+ * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event
+ * @kretprobe: Is this a return probe?
+ * @name: The name of the kprobe event
+ * @loc: The location of the kprobe event
+ * @...: Variable number of arg (pairs), one pair for each field
+ *
+ * NOTE: Users normally won't want to call this function directly, but
+ * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
+ * adds a NULL to the end of the arg list.  If this function is used
+ * directly, make sure the last arg in the variable arg list is NULL.
+ *
+ * Generate a kprobe event command to be executed by
+ * kprobe_event_gen_cmd_end().  This function can be used to generate the
+ * complete command or only the first part of it; in the latter case,
+ * kprobe_event_add_fields() can be used to add more fields following this.
+ *
+ * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
+ * returns -EINVAL if @loc == NULL.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
+				 const char *name, const char *loc, ...)
+{
+	char buf[MAX_EVENT_NAME_LEN];
+	struct dynevent_arg arg;
+	va_list args;
+	int ret;
+
+	if (cmd->type != DYNEVENT_TYPE_KPROBE)
+		return -EINVAL;
+
+	if (!loc)
+		return -EINVAL;
+
+	if (kretprobe)
+		snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
+	else
+		snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
+
+	ret = dynevent_str_add(cmd, buf);
+	if (ret)
+		return ret;
+
+	dynevent_arg_init(&arg, 0);
+	arg.str = loc;
+	ret = dynevent_arg_add(cmd, &arg, NULL);
+	if (ret)
+		return ret;
+
+	va_start(args, loc);
+	for (;;) {
+		const char *field;
+
+		field = va_arg(args, const char *);
+		if (!field)
+			break;
+
+		if (++cmd->n_fields > MAX_TRACE_ARGS) {
+			ret = -EINVAL;
+			break;
+		}
+
+		arg.str = field;
+		ret = dynevent_arg_add(cmd, &arg, NULL);
+		if (ret)
+			break;
+	}
+	va_end(args);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
+
+/**
+ * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event
+ * @...: Variable number of arg (pairs), one pair for each field
+ *
+ * NOTE: Users normally won't want to call this function directly, but
+ * rather use the kprobe_event_add_fields() wrapper, which
+ * automatically adds a NULL to the end of the arg list.  If this
+ * function is used directly, make sure the last arg in the variable
+ * arg list is NULL.
+ *
+ * Add probe fields to an existing kprobe command using a variable
+ * list of args.  Fields are added in the same order they're listed.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
+{
+	struct dynevent_arg arg;
+	va_list args;
+	int ret = 0;
+
+	if (cmd->type != DYNEVENT_TYPE_KPROBE)
+		return -EINVAL;
+
+	dynevent_arg_init(&arg, 0);
+
+	va_start(args, cmd);
+	for (;;) {
+		const char *field;
+
+		field = va_arg(args, const char *);
+		if (!field)
+			break;
+
+		if (++cmd->n_fields > MAX_TRACE_ARGS) {
+			ret = -EINVAL;
+			break;
+		}
+
+		arg.str = field;
+		ret = dynevent_arg_add(cmd, &arg, NULL);
+		if (ret)
+			break;
+	}
+	va_end(args);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
+
+/**
+ * kprobe_event_delete - Delete a kprobe event
+ * @name: The name of the kprobe event to delete
+ *
+ * Delete a kprobe event with the give @name from kernel code rather
+ * than directly from the command line.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int kprobe_event_delete(const char *name)
+{
+	char buf[MAX_EVENT_NAME_LEN];
+
+	snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
+
+	return create_or_delete_trace_kprobe(buf);
+}
+EXPORT_SYMBOL_GPL(kprobe_event_delete);
+
+static int trace_kprobe_release(struct dyn_event *ev)
+{
+	struct trace_kprobe *tk = to_trace_kprobe(ev);
+	int ret = unregister_trace_kprobe(tk);
+
+	if (!ret)
+		free_trace_kprobe(tk);
+	return ret;
+}
+
+static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
+{
+	struct trace_kprobe *tk = to_trace_kprobe(ev);
+	int i;
+
+	seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
+	if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
+		seq_printf(m, "%d", tk->rp.maxactive);
+	seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
+				trace_probe_name(&tk->tp));
+
+	if (!tk->symbol)
+		seq_printf(m, " 0x%p", tk->rp.kp.addr);
+	else if (tk->rp.kp.offset)
+		seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
+			   tk->rp.kp.offset);
+	else
+		seq_printf(m, " %s", trace_kprobe_symbol(tk));
+
+	for (i = 0; i < tk->tp.nr_args; i++)
+		seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
+	seq_putc(m, '\n');
+
+	return 0;
+}
+
+static int probes_seq_show(struct seq_file *m, void *v)
+{
+	struct dyn_event *ev = v;
+
+	if (!is_trace_kprobe(ev))
+		return 0;
+
+	return trace_kprobe_show(m, ev);
+}
+
+static const struct seq_operations probes_seq_op = {
+	.start  = dyn_event_seq_start,
+	.next   = dyn_event_seq_next,
+	.stop   = dyn_event_seq_stop,
+	.show   = probes_seq_show
+};
+
+static int probes_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+		ret = dyn_events_release_all(&trace_kprobe_ops);
+		if (ret < 0)
+			return ret;
+	}
+
+	return seq_open(file, &probes_seq_op);
+}
+
+static ssize_t probes_write(struct file *file, const char __user *buffer,
+			    size_t count, loff_t *ppos)
+{
+	return trace_parse_run_command(file, buffer, count, ppos,
+				       create_or_delete_trace_kprobe);
+}
+
+static const struct file_operations kprobe_events_ops = {
+	.owner          = THIS_MODULE,
+	.open           = probes_open,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release        = seq_release,
+	.write		= probes_write,
+};
+
+/* Probes profiling interfaces */
+static int probes_profile_seq_show(struct seq_file *m, void *v)
+{
+	struct dyn_event *ev = v;
+	struct trace_kprobe *tk;
+	unsigned long nmissed;
+
+	if (!is_trace_kprobe(ev))
+		return 0;
+
+	tk = to_trace_kprobe(ev);
+	nmissed = trace_kprobe_is_return(tk) ?
+		tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
+	seq_printf(m, "  %-44s %15lu %15lu\n",
+		   trace_probe_name(&tk->tp),
+		   trace_kprobe_nhit(tk),
+		   nmissed);
+
+	return 0;
+}
+
+static const struct seq_operations profile_seq_op = {
+	.start  = dyn_event_seq_start,
+	.next   = dyn_event_seq_next,
+	.stop   = dyn_event_seq_stop,
+	.show   = probes_profile_seq_show
+};
+
+static int profile_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	return seq_open(file, &profile_seq_op);
+}
+
+static const struct file_operations kprobe_profile_ops = {
+	.owner          = THIS_MODULE,
+	.open           = profile_open,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release        = seq_release,
+};
+
+/* Kprobe specific fetch functions */
+
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline int
+fetch_store_strlen_user(unsigned long addr)
+{
+	return kern_fetch_store_strlen_user(addr);
+}
+
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline int
+fetch_store_strlen(unsigned long addr)
+{
+	return kern_fetch_store_strlen(addr);
+}
+
+/*
+ * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
+ * with max length and relative data location.
+ */
+static nokprobe_inline int
+fetch_store_string_user(unsigned long addr, void *dest, void *base)
+{
+	return kern_fetch_store_string_user(addr, dest, base);
+}
+
+/*
+ * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
+ * length and relative data location.
+ */
+static nokprobe_inline int
+fetch_store_string(unsigned long addr, void *dest, void *base)
+{
+	return kern_fetch_store_string(addr, dest, base);
+}
+
+static nokprobe_inline int
+probe_mem_read_user(void *dest, void *src, size_t size)
+{
+	const void __user *uaddr =  (__force const void __user *)src;
+
+	return copy_from_user_nofault(dest, uaddr, size);
+}
+
+static nokprobe_inline int
+probe_mem_read(void *dest, void *src, size_t size)
+{
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+	if ((unsigned long)src < TASK_SIZE)
+		return probe_mem_read_user(dest, src, size);
+#endif
+	return copy_from_kernel_nofault(dest, src, size);
+}
+
+/* Note that we don't verify it, since the code does not come from user space */
+static int
+process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
+		   void *base)
+{
+	struct pt_regs *regs = rec;
+	unsigned long val;
+
+retry:
+	/* 1st stage: get value from context */
+	switch (code->op) {
+	case FETCH_OP_REG:
+		val = regs_get_register(regs, code->param);
+		break;
+	case FETCH_OP_STACK:
+		val = regs_get_kernel_stack_nth(regs, code->param);
+		break;
+	case FETCH_OP_STACKP:
+		val = kernel_stack_pointer(regs);
+		break;
+	case FETCH_OP_RETVAL:
+		val = regs_return_value(regs);
+		break;
+	case FETCH_OP_IMM:
+		val = code->immediate;
+		break;
+	case FETCH_OP_COMM:
+		val = (unsigned long)current->comm;
+		break;
+	case FETCH_OP_DATA:
+		val = (unsigned long)code->data;
+		break;
+#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
+	case FETCH_OP_ARG:
+		val = regs_get_kernel_argument(regs, code->param);
+		break;
+#endif
+	case FETCH_NOP_SYMBOL:	/* Ignore a place holder */
+		code++;
+		goto retry;
+	default:
+		return -EILSEQ;
+	}
+	code++;
+
+	return process_fetch_insn_bottom(code, val, dest, base);
+}
+NOKPROBE_SYMBOL(process_fetch_insn)
+
+/* Kprobe handler */
+static nokprobe_inline void
+__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
+		    struct trace_event_file *trace_file)
+{
+	struct kprobe_trace_entry_head *entry;
+	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
+	struct trace_event_buffer fbuffer;
+	int dsize;
+
+	WARN_ON(call != trace_file->event_call);
+
+	if (trace_trigger_soft_disabled(trace_file))
+		return;
+
+	dsize = __get_data_size(&tk->tp, regs);
+
+	entry = trace_event_buffer_reserve(&fbuffer, trace_file,
+					   sizeof(*entry) + tk->tp.size + dsize);
+	if (!entry)
+		return;
+
+	fbuffer.regs = regs;
+	entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
+	entry->ip = (unsigned long)tk->rp.kp.addr;
+	store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
+
+	trace_event_buffer_commit(&fbuffer);
+}
+
+static void
+kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
+{
+	struct event_file_link *link;
+
+	trace_probe_for_each_link_rcu(link, &tk->tp)
+		__kprobe_trace_func(tk, regs, link->file);
+}
+NOKPROBE_SYMBOL(kprobe_trace_func);
+
+/* Kretprobe handler */
+static nokprobe_inline void
+__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
+		       struct pt_regs *regs,
+		       struct trace_event_file *trace_file)
+{
+	struct kretprobe_trace_entry_head *entry;
+	struct trace_event_buffer fbuffer;
+	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
+	int dsize;
+
+	WARN_ON(call != trace_file->event_call);
+
+	if (trace_trigger_soft_disabled(trace_file))
+		return;
+
+	dsize = __get_data_size(&tk->tp, regs);
+
+	entry = trace_event_buffer_reserve(&fbuffer, trace_file,
+					   sizeof(*entry) + tk->tp.size + dsize);
+	if (!entry)
+		return;
+
+	fbuffer.regs = regs;
+	entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
+	entry->func = (unsigned long)tk->rp.kp.addr;
+	entry->ret_ip = get_kretprobe_retaddr(ri);
+	store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
+
+	trace_event_buffer_commit(&fbuffer);
+}
+
+static void
+kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
+		     struct pt_regs *regs)
+{
+	struct event_file_link *link;
+
+	trace_probe_for_each_link_rcu(link, &tk->tp)
+		__kretprobe_trace_func(tk, ri, regs, link->file);
+}
+NOKPROBE_SYMBOL(kretprobe_trace_func);
+
+/* Event entry printers */
+static enum print_line_t
+print_kprobe_event(struct trace_iterator *iter, int flags,
+		   struct trace_event *event)
+{
+	struct kprobe_trace_entry_head *field;
+	struct trace_seq *s = &iter->seq;
+	struct trace_probe *tp;
+
+	field = (struct kprobe_trace_entry_head *)iter->ent;
+	tp = trace_probe_primary_from_call(
+		container_of(event, struct trace_event_call, event));
+	if (WARN_ON_ONCE(!tp))
+		goto out;
+
+	trace_seq_printf(s, "%s: (", trace_probe_name(tp));
+
+	if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
+		goto out;
+
+	trace_seq_putc(s, ')');
+
+	if (print_probe_args(s, tp->args, tp->nr_args,
+			     (u8 *)&field[1], field) < 0)
+		goto out;
+
+	trace_seq_putc(s, '\n');
+ out:
+	return trace_handle_return(s);
+}
+
+static enum print_line_t
+print_kretprobe_event(struct trace_iterator *iter, int flags,
+		      struct trace_event *event)
+{
+	struct kretprobe_trace_entry_head *field;
+	struct trace_seq *s = &iter->seq;
+	struct trace_probe *tp;
+
+	field = (struct kretprobe_trace_entry_head *)iter->ent;
+	tp = trace_probe_primary_from_call(
+		container_of(event, struct trace_event_call, event));
+	if (WARN_ON_ONCE(!tp))
+		goto out;
+
+	trace_seq_printf(s, "%s: (", trace_probe_name(tp));
+
+	if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
+		goto out;
+
+	trace_seq_puts(s, " <- ");
+
+	if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
+		goto out;
+
+	trace_seq_putc(s, ')');
+
+	if (print_probe_args(s, tp->args, tp->nr_args,
+			     (u8 *)&field[1], field) < 0)
+		goto out;
+
+	trace_seq_putc(s, '\n');
+
+ out:
+	return trace_handle_return(s);
+}
+
+
+static int kprobe_event_define_fields(struct trace_event_call *event_call)
+{
+	int ret;
+	struct kprobe_trace_entry_head field;
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(event_call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENOENT;
+
+	DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
+
+	return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
+}
+
+static int kretprobe_event_define_fields(struct trace_event_call *event_call)
+{
+	int ret;
+	struct kretprobe_trace_entry_head field;
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(event_call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENOENT;
+
+	DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
+	DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
+
+	return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
+}
+
+#ifdef CONFIG_PERF_EVENTS
+
+/* Kprobe profile handler */
+static int
+kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
+{
+	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
+	struct kprobe_trace_entry_head *entry;
+	struct hlist_head *head;
+	int size, __size, dsize;
+	int rctx;
+
+	if (bpf_prog_array_valid(call)) {
+		unsigned long orig_ip = instruction_pointer(regs);
+		int ret;
+
+		ret = trace_call_bpf(call, regs);
+
+		/*
+		 * We need to check and see if we modified the pc of the
+		 * pt_regs, and if so return 1 so that we don't do the
+		 * single stepping.
+		 */
+		if (orig_ip != instruction_pointer(regs))
+			return 1;
+		if (!ret)
+			return 0;
+	}
+
+	head = this_cpu_ptr(call->perf_events);
+	if (hlist_empty(head))
+		return 0;
+
+	dsize = __get_data_size(&tk->tp, regs);
+	__size = sizeof(*entry) + tk->tp.size + dsize;
+	size = ALIGN(__size + sizeof(u32), sizeof(u64));
+	size -= sizeof(u32);
+
+	entry = perf_trace_buf_alloc(size, NULL, &rctx);
+	if (!entry)
+		return 0;
+
+	entry->ip = (unsigned long)tk->rp.kp.addr;
+	memset(&entry[1], 0, dsize);
+	store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
+	perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
+			      head, NULL);
+	return 0;
+}
+NOKPROBE_SYMBOL(kprobe_perf_func);
+
+/* Kretprobe profile handler */
+static void
+kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
+		    struct pt_regs *regs)
+{
+	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
+	struct kretprobe_trace_entry_head *entry;
+	struct hlist_head *head;
+	int size, __size, dsize;
+	int rctx;
+
+	if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
+		return;
+
+	head = this_cpu_ptr(call->perf_events);
+	if (hlist_empty(head))
+		return;
+
+	dsize = __get_data_size(&tk->tp, regs);
+	__size = sizeof(*entry) + tk->tp.size + dsize;
+	size = ALIGN(__size + sizeof(u32), sizeof(u64));
+	size -= sizeof(u32);
+
+	entry = perf_trace_buf_alloc(size, NULL, &rctx);
+	if (!entry)
+		return;
+
+	entry->func = (unsigned long)tk->rp.kp.addr;
+	entry->ret_ip = get_kretprobe_retaddr(ri);
+	store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
+	perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
+			      head, NULL);
+}
+NOKPROBE_SYMBOL(kretprobe_perf_func);
+
+int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
+			const char **symbol, u64 *probe_offset,
+			u64 *probe_addr, bool perf_type_tracepoint)
+{
+	const char *pevent = trace_event_name(event->tp_event);
+	const char *group = event->tp_event->class->system;
+	struct trace_kprobe *tk;
+
+	if (perf_type_tracepoint)
+		tk = find_trace_kprobe(pevent, group);
+	else
+		tk = trace_kprobe_primary_from_call(event->tp_event);
+	if (!tk)
+		return -EINVAL;
+
+	*fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
+					      : BPF_FD_TYPE_KPROBE;
+	if (tk->symbol) {
+		*symbol = tk->symbol;
+		*probe_offset = tk->rp.kp.offset;
+		*probe_addr = 0;
+	} else {
+		*symbol = NULL;
+		*probe_offset = 0;
+		*probe_addr = (unsigned long)tk->rp.kp.addr;
+	}
+	return 0;
+}
+#endif	/* CONFIG_PERF_EVENTS */
+
+/*
+ * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
+ *
+ * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
+ * lockless, but we can't race with this __init function.
+ */
+static int kprobe_register(struct trace_event_call *event,
+			   enum trace_reg type, void *data)
+{
+	struct trace_event_file *file = data;
+
+	switch (type) {
+	case TRACE_REG_REGISTER:
+		return enable_trace_kprobe(event, file);
+	case TRACE_REG_UNREGISTER:
+		return disable_trace_kprobe(event, file);
+
+#ifdef CONFIG_PERF_EVENTS
+	case TRACE_REG_PERF_REGISTER:
+		return enable_trace_kprobe(event, NULL);
+	case TRACE_REG_PERF_UNREGISTER:
+		return disable_trace_kprobe(event, NULL);
+	case TRACE_REG_PERF_OPEN:
+	case TRACE_REG_PERF_CLOSE:
+	case TRACE_REG_PERF_ADD:
+	case TRACE_REG_PERF_DEL:
+		return 0;
+#endif
+	}
+	return 0;
+}
+
+static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
+{
+	struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
+	int ret = 0;
+
+	raw_cpu_inc(*tk->nhit);
+
+	if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
+		kprobe_trace_func(tk, regs);
+#ifdef CONFIG_PERF_EVENTS
+	if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
+		ret = kprobe_perf_func(tk, regs);
+#endif
+	return ret;
+}
+NOKPROBE_SYMBOL(kprobe_dispatcher);
+
+static int
+kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
+{
+	struct kretprobe *rp = get_kretprobe(ri);
+	struct trace_kprobe *tk;
+
+	/*
+	 * There is a small chance that get_kretprobe(ri) returns NULL when
+	 * the kretprobe is unregister on another CPU between kretprobe's
+	 * trampoline_handler and this function.
+	 */
+	if (unlikely(!rp))
+		return 0;
+
+	tk = container_of(rp, struct trace_kprobe, rp);
+	raw_cpu_inc(*tk->nhit);
+
+	if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
+		kretprobe_trace_func(tk, ri, regs);
+#ifdef CONFIG_PERF_EVENTS
+	if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
+		kretprobe_perf_func(tk, ri, regs);
+#endif
+	return 0;	/* We don't tweak kernel, so just return 0 */
+}
+NOKPROBE_SYMBOL(kretprobe_dispatcher);
+
+static struct trace_event_functions kretprobe_funcs = {
+	.trace		= print_kretprobe_event
+};
+
+static struct trace_event_functions kprobe_funcs = {
+	.trace		= print_kprobe_event
+};
+
+static struct trace_event_fields kretprobe_fields_array[] = {
+	{ .type = TRACE_FUNCTION_TYPE,
+	  .define_fields = kretprobe_event_define_fields },
+	{}
+};
+
+static struct trace_event_fields kprobe_fields_array[] = {
+	{ .type = TRACE_FUNCTION_TYPE,
+	  .define_fields = kprobe_event_define_fields },
+	{}
+};
+
+static inline void init_trace_event_call(struct trace_kprobe *tk)
+{
+	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
+
+	if (trace_kprobe_is_return(tk)) {
+		call->event.funcs = &kretprobe_funcs;
+		call->class->fields_array = kretprobe_fields_array;
+	} else {
+		call->event.funcs = &kprobe_funcs;
+		call->class->fields_array = kprobe_fields_array;
+	}
+
+	call->flags = TRACE_EVENT_FL_KPROBE;
+	call->class->reg = kprobe_register;
+}
+
+static int register_kprobe_event(struct trace_kprobe *tk)
+{
+	init_trace_event_call(tk);
+
+	return trace_probe_register_event_call(&tk->tp);
+}
+
+static int unregister_kprobe_event(struct trace_kprobe *tk)
+{
+	return trace_probe_unregister_event_call(&tk->tp);
+}
+
+#ifdef CONFIG_PERF_EVENTS
+
+/* create a trace_kprobe, but don't add it to global lists */
+struct trace_event_call *
+create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
+			  bool is_return)
+{
+	enum probe_print_type ptype;
+	struct trace_kprobe *tk;
+	int ret;
+	char *event;
+
+	if (func) {
+		unsigned int count;
+
+		count = number_of_same_symbols(func);
+		if (count > 1)
+			/*
+			 * Users should use addr to remove the ambiguity of
+			 * using func only.
+			 */
+			return ERR_PTR(-EADDRNOTAVAIL);
+		else if (count == 0)
+			/*
+			 * We can return ENOENT earlier than when register the
+			 * kprobe.
+			 */
+			return ERR_PTR(-ENOENT);
+	}
+
+	/*
+	 * local trace_kprobes are not added to dyn_event, so they are never
+	 * searched in find_trace_kprobe(). Therefore, there is no concern of
+	 * duplicated name here.
+	 */
+	event = func ? func : "DUMMY_EVENT";
+
+	tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
+				offs, 0 /* maxactive */, 0 /* nargs */,
+				is_return);
+
+	if (IS_ERR(tk)) {
+		pr_info("Failed to allocate trace_probe.(%d)\n",
+			(int)PTR_ERR(tk));
+		return ERR_CAST(tk);
+	}
+
+	init_trace_event_call(tk);
+
+	ptype = trace_kprobe_is_return(tk) ?
+		PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
+	if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	ret = __register_trace_kprobe(tk);
+	if (ret < 0)
+		goto error;
+
+	return trace_probe_event_call(&tk->tp);
+error:
+	free_trace_kprobe(tk);
+	return ERR_PTR(ret);
+}
+
+void destroy_local_trace_kprobe(struct trace_event_call *event_call)
+{
+	struct trace_kprobe *tk;
+
+	tk = trace_kprobe_primary_from_call(event_call);
+	if (unlikely(!tk))
+		return;
+
+	if (trace_probe_is_enabled(&tk->tp)) {
+		WARN_ON(1);
+		return;
+	}
+
+	__unregister_trace_kprobe(tk);
+
+	free_trace_kprobe(tk);
+}
+#endif /* CONFIG_PERF_EVENTS */
+
+static __init void enable_boot_kprobe_events(void)
+{
+	struct trace_array *tr = top_trace_array();
+	struct trace_event_file *file;
+	struct trace_kprobe *tk;
+	struct dyn_event *pos;
+
+	mutex_lock(&event_mutex);
+	for_each_trace_kprobe(tk, pos) {
+		list_for_each_entry(file, &tr->events, list)
+			if (file->event_call == trace_probe_event_call(&tk->tp))
+				trace_event_enable_disable(file, 1, 0);
+	}
+	mutex_unlock(&event_mutex);
+}
+
+static __init void setup_boot_kprobe_events(void)
+{
+	char *p, *cmd = kprobe_boot_events_buf;
+	int ret;
+
+	strreplace(kprobe_boot_events_buf, ',', ' ');
+
+	while (cmd && *cmd != '\0') {
+		p = strchr(cmd, ';');
+		if (p)
+			*p++ = '\0';
+
+		ret = create_or_delete_trace_kprobe(cmd);
+		if (ret)
+			pr_warn("Failed to add event(%d): %s\n", ret, cmd);
+
+		cmd = p;
+	}
+
+	enable_boot_kprobe_events();
+}
+
+/*
+ * Register dynevent at core_initcall. This allows kernel to setup kprobe
+ * events in postcore_initcall without tracefs.
+ */
+static __init int init_kprobe_trace_early(void)
+{
+	int ret;
+
+	ret = dyn_event_register(&trace_kprobe_ops);
+	if (ret)
+		return ret;
+
+	if (register_module_notifier(&trace_kprobe_module_nb))
+		return -EINVAL;
+
+	return 0;
+}
+core_initcall(init_kprobe_trace_early);
+
+/* Make a tracefs interface for controlling probe points */
+static __init int init_kprobe_trace(void)
+{
+	int ret;
+
+	ret = tracing_init_dentry();
+	if (ret)
+		return 0;
+
+	/* Event list interface */
+	trace_create_file("kprobe_events", TRACE_MODE_WRITE,
+			  NULL, NULL, &kprobe_events_ops);
+
+	/* Profile interface */
+	trace_create_file("kprobe_profile", TRACE_MODE_READ,
+			  NULL, NULL, &kprobe_profile_ops);
+
+	setup_boot_kprobe_events();
+
+	return 0;
+}
+fs_initcall(init_kprobe_trace);
+
+
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+static __init struct trace_event_file *
+find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
+{
+	struct trace_event_file *file;
+
+	list_for_each_entry(file, &tr->events, list)
+		if (file->event_call == trace_probe_event_call(&tk->tp))
+			return file;
+
+	return NULL;
+}
+
+/*
+ * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
+ * stage, we can do this lockless.
+ */
+static __init int kprobe_trace_self_tests_init(void)
+{
+	int ret, warn = 0;
+	int (*target)(int, int, int, int, int, int);
+	struct trace_kprobe *tk;
+	struct trace_event_file *file;
+
+	if (tracing_is_disabled())
+		return -ENODEV;
+
+	if (tracing_selftest_disabled)
+		return 0;
+
+	target = kprobe_trace_selftest_target;
+
+	pr_info("Testing kprobe tracing: ");
+
+	ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
+	if (WARN_ON_ONCE(ret)) {
+		pr_warn("error on probing function entry.\n");
+		warn++;
+	} else {
+		/* Enable trace point */
+		tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
+		if (WARN_ON_ONCE(tk == NULL)) {
+			pr_warn("error on getting new probe.\n");
+			warn++;
+		} else {
+			file = find_trace_probe_file(tk, top_trace_array());
+			if (WARN_ON_ONCE(file == NULL)) {
+				pr_warn("error on getting probe file.\n");
+				warn++;
+			} else
+				enable_trace_kprobe(
+					trace_probe_event_call(&tk->tp), file);
+		}
+	}
+
+	ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
+	if (WARN_ON_ONCE(ret)) {
+		pr_warn("error on probing function return.\n");
+		warn++;
+	} else {
+		/* Enable trace point */
+		tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
+		if (WARN_ON_ONCE(tk == NULL)) {
+			pr_warn("error on getting 2nd new probe.\n");
+			warn++;
+		} else {
+			file = find_trace_probe_file(tk, top_trace_array());
+			if (WARN_ON_ONCE(file == NULL)) {
+				pr_warn("error on getting probe file.\n");
+				warn++;
+			} else
+				enable_trace_kprobe(
+					trace_probe_event_call(&tk->tp), file);
+		}
+	}
+
+	if (warn)
+		goto end;
+
+	ret = target(1, 2, 3, 4, 5, 6);
+
+	/*
+	 * Not expecting an error here, the check is only to prevent the
+	 * optimizer from removing the call to target() as otherwise there
+	 * are no side-effects and the call is never performed.
+	 */
+	if (ret != 21)
+		warn++;
+
+	/* Disable trace points before removing it */
+	tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
+	if (WARN_ON_ONCE(tk == NULL)) {
+		pr_warn("error on getting test probe.\n");
+		warn++;
+	} else {
+		if (trace_kprobe_nhit(tk) != 1) {
+			pr_warn("incorrect number of testprobe hits\n");
+			warn++;
+		}
+
+		file = find_trace_probe_file(tk, top_trace_array());
+		if (WARN_ON_ONCE(file == NULL)) {
+			pr_warn("error on getting probe file.\n");
+			warn++;
+		} else
+			disable_trace_kprobe(
+				trace_probe_event_call(&tk->tp), file);
+	}
+
+	tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
+	if (WARN_ON_ONCE(tk == NULL)) {
+		pr_warn("error on getting 2nd test probe.\n");
+		warn++;
+	} else {
+		if (trace_kprobe_nhit(tk) != 1) {
+			pr_warn("incorrect number of testprobe2 hits\n");
+			warn++;
+		}
+
+		file = find_trace_probe_file(tk, top_trace_array());
+		if (WARN_ON_ONCE(file == NULL)) {
+			pr_warn("error on getting probe file.\n");
+			warn++;
+		} else
+			disable_trace_kprobe(
+				trace_probe_event_call(&tk->tp), file);
+	}
+
+	ret = create_or_delete_trace_kprobe("-:testprobe");
+	if (WARN_ON_ONCE(ret)) {
+		pr_warn("error on deleting a probe.\n");
+		warn++;
+	}
+
+	ret = create_or_delete_trace_kprobe("-:testprobe2");
+	if (WARN_ON_ONCE(ret)) {
+		pr_warn("error on deleting a probe.\n");
+		warn++;
+	}
+
+end:
+	ret = dyn_events_release_all(&trace_kprobe_ops);
+	if (WARN_ON_ONCE(ret)) {
+		pr_warn("error on cleaning up probes.\n");
+		warn++;
+	}
+	/*
+	 * Wait for the optimizer work to finish. Otherwise it might fiddle
+	 * with probes in already freed __init text.
+	 */
+	wait_for_kprobe_optimizer();
+	if (warn)
+		pr_cont("NG: Some tests are failed. Please check them.\n");
+	else
+		pr_cont("OK\n");
+	return 0;
+}
+
+late_initcall(kprobe_trace_self_tests_init);
+
+#endif
diff --git a/kernel/trace/trace_kprobe_selftest.c b/kernel/trace/trace_kprobe_selftest.c
new file mode 100644
index 000000000..16548ee4c
--- /dev/null
+++ b/kernel/trace/trace_kprobe_selftest.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Function used during the kprobe self test. This function is in a separate
+ * compile unit so it can be compile with CC_FLAGS_FTRACE to ensure that it
+ * can be probed by the selftests.
+ */
+int kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
+{
+	return a1 + a2 + a3 + a4 + a5 + a6;
+}
diff --git a/kernel/trace/trace_kprobe_selftest.h b/kernel/trace/trace_kprobe_selftest.h
new file mode 100644
index 000000000..c4fc7268b
--- /dev/null
+++ b/kernel/trace/trace_kprobe_selftest.h
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Function used during the kprobe self test. This function is in a separate
+ * compile unit so it can be compile with CC_FLAGS_FTRACE to ensure that it
+ * can be probed by the selftests.
+ */
+int kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6);
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
new file mode 100644
index 000000000..64e77b513
--- /dev/null
+++ b/kernel/trace/trace_mmiotrace.c
@@ -0,0 +1,362 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Memory mapped I/O tracing
+ *
+ * Copyright (C) 2008 Pekka Paalanen <pq@iki.fi>
+ */
+
+#include <linux/kernel.h>
+#include <linux/mmiotrace.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+
+#include <linux/atomic.h>
+
+#include "trace.h"
+#include "trace_output.h"
+
+struct header_iter {
+	struct pci_dev *dev;
+};
+
+static struct trace_array *mmio_trace_array;
+static bool overrun_detected;
+static unsigned long prev_overruns;
+static atomic_t dropped_count;
+
+static void mmio_reset_data(struct trace_array *tr)
+{
+	overrun_detected = false;
+	prev_overruns = 0;
+
+	tracing_reset_online_cpus(&tr->array_buffer);
+}
+
+static int mmio_trace_init(struct trace_array *tr)
+{
+	pr_debug("in %s\n", __func__);
+	mmio_trace_array = tr;
+
+	mmio_reset_data(tr);
+	enable_mmiotrace();
+	return 0;
+}
+
+static void mmio_trace_reset(struct trace_array *tr)
+{
+	pr_debug("in %s\n", __func__);
+
+	disable_mmiotrace();
+	mmio_reset_data(tr);
+	mmio_trace_array = NULL;
+}
+
+static void mmio_trace_start(struct trace_array *tr)
+{
+	pr_debug("in %s\n", __func__);
+	mmio_reset_data(tr);
+}
+
+static void mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
+{
+	int i;
+	resource_size_t start, end;
+	const struct pci_driver *drv = pci_dev_driver(dev);
+
+	trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
+			 dev->bus->number, dev->devfn,
+			 dev->vendor, dev->device, dev->irq);
+	for (i = 0; i < 7; i++) {
+		start = dev->resource[i].start;
+		trace_seq_printf(s, " %llx",
+			(unsigned long long)(start |
+			(dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
+	}
+	for (i = 0; i < 7; i++) {
+		start = dev->resource[i].start;
+		end = dev->resource[i].end;
+		trace_seq_printf(s, " %llx",
+			dev->resource[i].start < dev->resource[i].end ?
+			(unsigned long long)(end - start) + 1 : 0);
+	}
+	if (drv)
+		trace_seq_printf(s, " %s\n", drv->name);
+	else
+		trace_seq_puts(s, " \n");
+}
+
+static void destroy_header_iter(struct header_iter *hiter)
+{
+	if (!hiter)
+		return;
+	pci_dev_put(hiter->dev);
+	kfree(hiter);
+}
+
+static void mmio_pipe_open(struct trace_iterator *iter)
+{
+	struct header_iter *hiter;
+	struct trace_seq *s = &iter->seq;
+
+	trace_seq_puts(s, "VERSION 20070824\n");
+
+	hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
+	if (!hiter)
+		return;
+
+	hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
+	iter->private = hiter;
+}
+
+/* XXX: This is not called when the pipe is closed! */
+static void mmio_close(struct trace_iterator *iter)
+{
+	struct header_iter *hiter = iter->private;
+	destroy_header_iter(hiter);
+	iter->private = NULL;
+}
+
+static unsigned long count_overruns(struct trace_iterator *iter)
+{
+	unsigned long cnt = atomic_xchg(&dropped_count, 0);
+	unsigned long over = ring_buffer_overruns(iter->array_buffer->buffer);
+
+	if (over > prev_overruns)
+		cnt += over - prev_overruns;
+	prev_overruns = over;
+	return cnt;
+}
+
+static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
+				char __user *ubuf, size_t cnt, loff_t *ppos)
+{
+	ssize_t ret;
+	struct header_iter *hiter = iter->private;
+	struct trace_seq *s = &iter->seq;
+	unsigned long n;
+
+	n = count_overruns(iter);
+	if (n) {
+		/* XXX: This is later than where events were lost. */
+		trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
+		if (!overrun_detected)
+			pr_warn("mmiotrace has lost events\n");
+		overrun_detected = true;
+		goto print_out;
+	}
+
+	if (!hiter)
+		return 0;
+
+	mmio_print_pcidev(s, hiter->dev);
+	hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
+
+	if (!hiter->dev) {
+		destroy_header_iter(hiter);
+		iter->private = NULL;
+	}
+
+print_out:
+	ret = trace_seq_to_user(s, ubuf, cnt);
+	return (ret == -EBUSY) ? 0 : ret;
+}
+
+static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
+{
+	struct trace_entry *entry = iter->ent;
+	struct trace_mmiotrace_rw *field;
+	struct mmiotrace_rw *rw;
+	struct trace_seq *s	= &iter->seq;
+	unsigned long long t	= ns2usecs(iter->ts);
+	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
+	unsigned secs		= (unsigned long)t;
+
+	trace_assign_type(field, entry);
+	rw = &field->rw;
+
+	switch (rw->opcode) {
+	case MMIO_READ:
+		trace_seq_printf(s,
+			"R %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
+			rw->width, secs, usec_rem, rw->map_id,
+			(unsigned long long)rw->phys,
+			rw->value, rw->pc, 0);
+		break;
+	case MMIO_WRITE:
+		trace_seq_printf(s,
+			"W %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
+			rw->width, secs, usec_rem, rw->map_id,
+			(unsigned long long)rw->phys,
+			rw->value, rw->pc, 0);
+		break;
+	case MMIO_UNKNOWN_OP:
+		trace_seq_printf(s,
+			"UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
+			"%02lx 0x%lx %d\n",
+			secs, usec_rem, rw->map_id,
+			(unsigned long long)rw->phys,
+			(rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
+			(rw->value >> 0) & 0xff, rw->pc, 0);
+		break;
+	default:
+		trace_seq_puts(s, "rw what?\n");
+		break;
+	}
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t mmio_print_map(struct trace_iterator *iter)
+{
+	struct trace_entry *entry = iter->ent;
+	struct trace_mmiotrace_map *field;
+	struct mmiotrace_map *m;
+	struct trace_seq *s	= &iter->seq;
+	unsigned long long t	= ns2usecs(iter->ts);
+	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
+	unsigned secs		= (unsigned long)t;
+
+	trace_assign_type(field, entry);
+	m = &field->map;
+
+	switch (m->opcode) {
+	case MMIO_PROBE:
+		trace_seq_printf(s,
+			"MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
+			secs, usec_rem, m->map_id,
+			(unsigned long long)m->phys, m->virt, m->len,
+			0UL, 0);
+		break;
+	case MMIO_UNPROBE:
+		trace_seq_printf(s,
+			"UNMAP %u.%06lu %d 0x%lx %d\n",
+			secs, usec_rem, m->map_id, 0UL, 0);
+		break;
+	default:
+		trace_seq_puts(s, "map what?\n");
+		break;
+	}
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
+{
+	struct trace_entry *entry = iter->ent;
+	struct print_entry *print = (struct print_entry *)entry;
+	const char *msg		= print->buf;
+	struct trace_seq *s	= &iter->seq;
+	unsigned long long t	= ns2usecs(iter->ts);
+	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
+	unsigned secs		= (unsigned long)t;
+
+	/* The trailing newline must be in the message. */
+	trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t mmio_print_line(struct trace_iterator *iter)
+{
+	switch (iter->ent->type) {
+	case TRACE_MMIO_RW:
+		return mmio_print_rw(iter);
+	case TRACE_MMIO_MAP:
+		return mmio_print_map(iter);
+	case TRACE_PRINT:
+		return mmio_print_mark(iter);
+	default:
+		return TRACE_TYPE_HANDLED; /* ignore unknown entries */
+	}
+}
+
+static struct tracer mmio_tracer __read_mostly =
+{
+	.name		= "mmiotrace",
+	.init		= mmio_trace_init,
+	.reset		= mmio_trace_reset,
+	.start		= mmio_trace_start,
+	.pipe_open	= mmio_pipe_open,
+	.close		= mmio_close,
+	.read		= mmio_read,
+	.print_line	= mmio_print_line,
+	.noboot		= true,
+};
+
+__init static int init_mmio_trace(void)
+{
+	return register_tracer(&mmio_tracer);
+}
+device_initcall(init_mmio_trace);
+
+static void __trace_mmiotrace_rw(struct trace_array *tr,
+				struct trace_array_cpu *data,
+				struct mmiotrace_rw *rw)
+{
+	struct trace_event_call *call = &event_mmiotrace_rw;
+	struct trace_buffer *buffer = tr->array_buffer.buffer;
+	struct ring_buffer_event *event;
+	struct trace_mmiotrace_rw *entry;
+	unsigned int trace_ctx;
+
+	trace_ctx = tracing_gen_ctx_flags(0);
+	event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,
+					  sizeof(*entry), trace_ctx);
+	if (!event) {
+		atomic_inc(&dropped_count);
+		return;
+	}
+	entry	= ring_buffer_event_data(event);
+	entry->rw			= *rw;
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
+}
+
+void mmio_trace_rw(struct mmiotrace_rw *rw)
+{
+	struct trace_array *tr = mmio_trace_array;
+	struct trace_array_cpu *data = per_cpu_ptr(tr->array_buffer.data, smp_processor_id());
+	__trace_mmiotrace_rw(tr, data, rw);
+}
+
+static void __trace_mmiotrace_map(struct trace_array *tr,
+				struct trace_array_cpu *data,
+				struct mmiotrace_map *map)
+{
+	struct trace_event_call *call = &event_mmiotrace_map;
+	struct trace_buffer *buffer = tr->array_buffer.buffer;
+	struct ring_buffer_event *event;
+	struct trace_mmiotrace_map *entry;
+	unsigned int trace_ctx;
+
+	trace_ctx = tracing_gen_ctx_flags(0);
+	event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,
+					  sizeof(*entry), trace_ctx);
+	if (!event) {
+		atomic_inc(&dropped_count);
+		return;
+	}
+	entry	= ring_buffer_event_data(event);
+	entry->map			= *map;
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
+}
+
+void mmio_trace_mapping(struct mmiotrace_map *map)
+{
+	struct trace_array *tr = mmio_trace_array;
+	struct trace_array_cpu *data;
+
+	preempt_disable();
+	data = per_cpu_ptr(tr->array_buffer.data, smp_processor_id());
+	__trace_mmiotrace_map(tr, data, map);
+	preempt_enable();
+}
+
+int mmio_trace_printk(const char *fmt, va_list args)
+{
+	return trace_vprintk(0, fmt, args);
+}
diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c
new file mode 100644
index 000000000..50523f953
--- /dev/null
+++ b/kernel/trace/trace_nop.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * nop tracer
+ *
+ * Copyright (C) 2008 Steven Noonan <steven@uplinklabs.net>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/ftrace.h>
+
+#include "trace.h"
+
+/* Our two options */
+enum {
+	TRACE_NOP_OPT_ACCEPT = 0x1,
+	TRACE_NOP_OPT_REFUSE = 0x2
+};
+
+/* Options for the tracer (see trace_options file) */
+static struct tracer_opt nop_opts[] = {
+	/* Option that will be accepted by set_flag callback */
+	{ TRACER_OPT(test_nop_accept, TRACE_NOP_OPT_ACCEPT) },
+	/* Option that will be refused by set_flag callback */
+	{ TRACER_OPT(test_nop_refuse, TRACE_NOP_OPT_REFUSE) },
+	{ } /* Always set a last empty entry */
+};
+
+static struct tracer_flags nop_flags = {
+	/* You can check your flags value here when you want. */
+	.val = 0, /* By default: all flags disabled */
+	.opts = nop_opts
+};
+
+static struct trace_array	*ctx_trace;
+
+static void start_nop_trace(struct trace_array *tr)
+{
+	/* Nothing to do! */
+}
+
+static void stop_nop_trace(struct trace_array *tr)
+{
+	/* Nothing to do! */
+}
+
+static int nop_trace_init(struct trace_array *tr)
+{
+	ctx_trace = tr;
+	start_nop_trace(tr);
+	return 0;
+}
+
+static void nop_trace_reset(struct trace_array *tr)
+{
+	stop_nop_trace(tr);
+}
+
+/* It only serves as a signal handler and a callback to
+ * accept or refuse the setting of a flag.
+ * If you don't implement it, then the flag setting will be
+ * automatically accepted.
+ */
+static int nop_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
+{
+	/*
+	 * Note that you don't need to update nop_flags.val yourself.
+	 * The tracing Api will do it automatically if you return 0
+	 */
+	if (bit == TRACE_NOP_OPT_ACCEPT) {
+		printk(KERN_DEBUG "nop_test_accept flag set to %d: we accept."
+			" Now cat trace_options to see the result\n",
+			set);
+		return 0;
+	}
+
+	if (bit == TRACE_NOP_OPT_REFUSE) {
+		printk(KERN_DEBUG "nop_test_refuse flag set to %d: we refuse."
+			" Now cat trace_options to see the result\n",
+			set);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+
+struct tracer nop_trace __read_mostly =
+{
+	.name		= "nop",
+	.init		= nop_trace_init,
+	.reset		= nop_trace_reset,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest	= trace_selftest_startup_nop,
+#endif
+	.flags		= &nop_flags,
+	.set_flag	= nop_set_flag,
+	.allow_instances = true,
+};
+
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
new file mode 100644
index 000000000..26111b0ca
--- /dev/null
+++ b/kernel/trace/trace_osnoise.c
@@ -0,0 +1,2442 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * OS Noise Tracer: computes the OS Noise suffered by a running thread.
+ * Timerlat Tracer: measures the wakeup latency of a timer triggered IRQ and thread.
+ *
+ * Based on "hwlat_detector" tracer by:
+ *   Copyright (C) 2008-2009 Jon Masters, Red Hat, Inc. <jcm@redhat.com>
+ *   Copyright (C) 2013-2016 Steven Rostedt, Red Hat, Inc. <srostedt@redhat.com>
+ *   With feedback from Clark Williams <williams@redhat.com>
+ *
+ * And also based on the rtsl tracer presented on:
+ *  DE OLIVEIRA, Daniel Bristot, et al. Demystifying the real-time linux
+ *  scheduling latency. In: 32nd Euromicro Conference on Real-Time Systems
+ *  (ECRTS 2020). Schloss Dagstuhl-Leibniz-Zentrum fur Informatik, 2020.
+ *
+ * Copyright (C) 2021 Daniel Bristot de Oliveira, Red Hat, Inc. <bristot@redhat.com>
+ */
+
+#include <linux/kthread.h>
+#include <linux/tracefs.h>
+#include <linux/uaccess.h>
+#include <linux/cpumask.h>
+#include <linux/delay.h>
+#include <linux/sched/clock.h>
+#include <uapi/linux/sched/types.h>
+#include <linux/sched.h>
+#include "trace.h"
+
+#ifdef CONFIG_X86_LOCAL_APIC
+#include <asm/trace/irq_vectors.h>
+#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
+#endif /* CONFIG_X86_LOCAL_APIC */
+
+#include <trace/events/irq.h>
+#include <trace/events/sched.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/osnoise.h>
+
+/*
+ * Default values.
+ */
+#define BANNER			"osnoise: "
+#define DEFAULT_SAMPLE_PERIOD	1000000			/* 1s */
+#define DEFAULT_SAMPLE_RUNTIME	1000000			/* 1s */
+
+#define DEFAULT_TIMERLAT_PERIOD	1000			/* 1ms */
+#define DEFAULT_TIMERLAT_PRIO	95			/* FIFO 95 */
+
+/*
+ * trace_array of the enabled osnoise/timerlat instances.
+ */
+struct osnoise_instance {
+	struct list_head	list;
+	struct trace_array	*tr;
+};
+
+static struct list_head osnoise_instances;
+
+static bool osnoise_has_registered_instances(void)
+{
+	return !!list_first_or_null_rcu(&osnoise_instances,
+					struct osnoise_instance,
+					list);
+}
+
+/*
+ * osnoise_instance_registered - check if a tr is already registered
+ */
+static int osnoise_instance_registered(struct trace_array *tr)
+{
+	struct osnoise_instance *inst;
+	int found = 0;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(inst, &osnoise_instances, list) {
+		if (inst->tr == tr)
+			found = 1;
+	}
+	rcu_read_unlock();
+
+	return found;
+}
+
+/*
+ * osnoise_register_instance - register a new trace instance
+ *
+ * Register a trace_array *tr in the list of instances running
+ * osnoise/timerlat tracers.
+ */
+static int osnoise_register_instance(struct trace_array *tr)
+{
+	struct osnoise_instance *inst;
+
+	/*
+	 * register/unregister serialization is provided by trace's
+	 * trace_types_lock.
+	 */
+	lockdep_assert_held(&trace_types_lock);
+
+	inst = kmalloc(sizeof(*inst), GFP_KERNEL);
+	if (!inst)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD_RCU(&inst->list);
+	inst->tr = tr;
+	list_add_tail_rcu(&inst->list, &osnoise_instances);
+
+	return 0;
+}
+
+/*
+ *  osnoise_unregister_instance - unregister a registered trace instance
+ *
+ * Remove the trace_array *tr from the list of instances running
+ * osnoise/timerlat tracers.
+ */
+static void osnoise_unregister_instance(struct trace_array *tr)
+{
+	struct osnoise_instance *inst;
+	int found = 0;
+
+	/*
+	 * register/unregister serialization is provided by trace's
+	 * trace_types_lock.
+	 */
+	list_for_each_entry_rcu(inst, &osnoise_instances, list,
+				lockdep_is_held(&trace_types_lock)) {
+		if (inst->tr == tr) {
+			list_del_rcu(&inst->list);
+			found = 1;
+			break;
+		}
+	}
+
+	if (!found)
+		return;
+
+	kvfree_rcu(inst);
+}
+
+/*
+ * NMI runtime info.
+ */
+struct osn_nmi {
+	u64	count;
+	u64	delta_start;
+};
+
+/*
+ * IRQ runtime info.
+ */
+struct osn_irq {
+	u64	count;
+	u64	arrival_time;
+	u64	delta_start;
+};
+
+#define IRQ_CONTEXT	0
+#define THREAD_CONTEXT	1
+/*
+ * sofirq runtime info.
+ */
+struct osn_softirq {
+	u64	count;
+	u64	arrival_time;
+	u64	delta_start;
+};
+
+/*
+ * thread runtime info.
+ */
+struct osn_thread {
+	u64	count;
+	u64	arrival_time;
+	u64	delta_start;
+};
+
+/*
+ * Runtime information: this structure saves the runtime information used by
+ * one sampling thread.
+ */
+struct osnoise_variables {
+	struct task_struct	*kthread;
+	bool			sampling;
+	pid_t			pid;
+	struct osn_nmi		nmi;
+	struct osn_irq		irq;
+	struct osn_softirq	softirq;
+	struct osn_thread	thread;
+	local_t			int_counter;
+};
+
+/*
+ * Per-cpu runtime information.
+ */
+DEFINE_PER_CPU(struct osnoise_variables, per_cpu_osnoise_var);
+
+/*
+ * this_cpu_osn_var - Return the per-cpu osnoise_variables on its relative CPU
+ */
+static inline struct osnoise_variables *this_cpu_osn_var(void)
+{
+	return this_cpu_ptr(&per_cpu_osnoise_var);
+}
+
+#ifdef CONFIG_TIMERLAT_TRACER
+/*
+ * Runtime information for the timer mode.
+ */
+struct timerlat_variables {
+	struct task_struct	*kthread;
+	struct hrtimer		timer;
+	u64			rel_period;
+	u64			abs_period;
+	bool			tracing_thread;
+	u64			count;
+};
+
+DEFINE_PER_CPU(struct timerlat_variables, per_cpu_timerlat_var);
+
+/*
+ * this_cpu_tmr_var - Return the per-cpu timerlat_variables on its relative CPU
+ */
+static inline struct timerlat_variables *this_cpu_tmr_var(void)
+{
+	return this_cpu_ptr(&per_cpu_timerlat_var);
+}
+
+/*
+ * tlat_var_reset - Reset the values of the given timerlat_variables
+ */
+static inline void tlat_var_reset(void)
+{
+	struct timerlat_variables *tlat_var;
+	int cpu;
+	/*
+	 * So far, all the values are initialized as 0, so
+	 * zeroing the structure is perfect.
+	 */
+	for_each_cpu(cpu, cpu_online_mask) {
+		tlat_var = per_cpu_ptr(&per_cpu_timerlat_var, cpu);
+		memset(tlat_var, 0, sizeof(*tlat_var));
+	}
+}
+#else /* CONFIG_TIMERLAT_TRACER */
+#define tlat_var_reset()	do {} while (0)
+#endif /* CONFIG_TIMERLAT_TRACER */
+
+/*
+ * osn_var_reset - Reset the values of the given osnoise_variables
+ */
+static inline void osn_var_reset(void)
+{
+	struct osnoise_variables *osn_var;
+	int cpu;
+
+	/*
+	 * So far, all the values are initialized as 0, so
+	 * zeroing the structure is perfect.
+	 */
+	for_each_cpu(cpu, cpu_online_mask) {
+		osn_var = per_cpu_ptr(&per_cpu_osnoise_var, cpu);
+		memset(osn_var, 0, sizeof(*osn_var));
+	}
+}
+
+/*
+ * osn_var_reset_all - Reset the value of all per-cpu osnoise_variables
+ */
+static inline void osn_var_reset_all(void)
+{
+	osn_var_reset();
+	tlat_var_reset();
+}
+
+/*
+ * Tells NMIs to call back to the osnoise tracer to record timestamps.
+ */
+bool trace_osnoise_callback_enabled;
+
+/*
+ * osnoise sample structure definition. Used to store the statistics of a
+ * sample run.
+ */
+struct osnoise_sample {
+	u64			runtime;	/* runtime */
+	u64			noise;		/* noise */
+	u64			max_sample;	/* max single noise sample */
+	int			hw_count;	/* # HW (incl. hypervisor) interference */
+	int			nmi_count;	/* # NMIs during this sample */
+	int			irq_count;	/* # IRQs during this sample */
+	int			softirq_count;	/* # softirqs during this sample */
+	int			thread_count;	/* # threads during this sample */
+};
+
+#ifdef CONFIG_TIMERLAT_TRACER
+/*
+ * timerlat sample structure definition. Used to store the statistics of
+ * a sample run.
+ */
+struct timerlat_sample {
+	u64			timer_latency;	/* timer_latency */
+	unsigned int		seqnum;		/* unique sequence */
+	int			context;	/* timer context */
+};
+#endif
+
+/*
+ * Protect the interface.
+ */
+struct mutex interface_lock;
+
+/*
+ * Tracer data.
+ */
+static struct osnoise_data {
+	u64	sample_period;		/* total sampling period */
+	u64	sample_runtime;		/* active sampling portion of period */
+	u64	stop_tracing;		/* stop trace in the internal operation (loop/irq) */
+	u64	stop_tracing_total;	/* stop trace in the final operation (report/thread) */
+#ifdef CONFIG_TIMERLAT_TRACER
+	u64	timerlat_period;	/* timerlat period */
+	u64	print_stack;		/* print IRQ stack if total > */
+	int	timerlat_tracer;	/* timerlat tracer */
+#endif
+	bool	tainted;		/* infor users and developers about a problem */
+} osnoise_data = {
+	.sample_period			= DEFAULT_SAMPLE_PERIOD,
+	.sample_runtime			= DEFAULT_SAMPLE_RUNTIME,
+	.stop_tracing			= 0,
+	.stop_tracing_total		= 0,
+#ifdef CONFIG_TIMERLAT_TRACER
+	.print_stack			= 0,
+	.timerlat_period		= DEFAULT_TIMERLAT_PERIOD,
+	.timerlat_tracer		= 0,
+#endif
+};
+
+#ifdef CONFIG_TIMERLAT_TRACER
+static inline bool timerlat_enabled(void)
+{
+	return osnoise_data.timerlat_tracer;
+}
+
+static inline int timerlat_softirq_exit(struct osnoise_variables *osn_var)
+{
+	struct timerlat_variables *tlat_var = this_cpu_tmr_var();
+	/*
+	 * If the timerlat is enabled, but the irq handler did
+	 * not run yet enabling timerlat_tracer, do not trace.
+	 */
+	if (!tlat_var->tracing_thread) {
+		osn_var->softirq.arrival_time = 0;
+		osn_var->softirq.delta_start = 0;
+		return 0;
+	}
+	return 1;
+}
+
+static inline int timerlat_thread_exit(struct osnoise_variables *osn_var)
+{
+	struct timerlat_variables *tlat_var = this_cpu_tmr_var();
+	/*
+	 * If the timerlat is enabled, but the irq handler did
+	 * not run yet enabling timerlat_tracer, do not trace.
+	 */
+	if (!tlat_var->tracing_thread) {
+		osn_var->thread.delta_start = 0;
+		osn_var->thread.arrival_time = 0;
+		return 0;
+	}
+	return 1;
+}
+#else /* CONFIG_TIMERLAT_TRACER */
+static inline bool timerlat_enabled(void)
+{
+	return false;
+}
+
+static inline int timerlat_softirq_exit(struct osnoise_variables *osn_var)
+{
+	return 1;
+}
+static inline int timerlat_thread_exit(struct osnoise_variables *osn_var)
+{
+	return 1;
+}
+#endif
+
+#ifdef CONFIG_PREEMPT_RT
+/*
+ * Print the osnoise header info.
+ */
+static void print_osnoise_headers(struct seq_file *s)
+{
+	if (osnoise_data.tainted)
+		seq_puts(s, "# osnoise is tainted!\n");
+
+	seq_puts(s, "#                                _-------=> irqs-off\n");
+	seq_puts(s, "#                               / _------=> need-resched\n");
+	seq_puts(s, "#                              | / _-----=> need-resched-lazy\n");
+	seq_puts(s, "#                              || / _----=> hardirq/softirq\n");
+	seq_puts(s, "#                              ||| / _---=> preempt-depth\n");
+	seq_puts(s, "#                              |||| / _--=> preempt-lazy-depth\n");
+	seq_puts(s, "#                              ||||| / _-=> migrate-disable\n");
+
+	seq_puts(s, "#                              |||||| /          ");
+	seq_puts(s, "                                     MAX\n");
+
+	seq_puts(s, "#                              ||||| /                         ");
+	seq_puts(s, "                    SINGLE      Interference counters:\n");
+
+	seq_puts(s, "#                              |||||||               RUNTIME   ");
+	seq_puts(s, "   NOISE  %% OF CPU  NOISE    +-----------------------------+\n");
+
+	seq_puts(s, "#           TASK-PID      CPU# |||||||   TIMESTAMP    IN US    ");
+	seq_puts(s, "   IN US  AVAILABLE  IN US     HW    NMI    IRQ   SIRQ THREAD\n");
+
+	seq_puts(s, "#              | |         |   |||||||      |           |      ");
+	seq_puts(s, "       |    |            |      |      |      |      |      |\n");
+}
+#else /* CONFIG_PREEMPT_RT */
+static void print_osnoise_headers(struct seq_file *s)
+{
+	if (osnoise_data.tainted)
+		seq_puts(s, "# osnoise is tainted!\n");
+
+	seq_puts(s, "#                                _-----=> irqs-off\n");
+	seq_puts(s, "#                               / _----=> need-resched\n");
+	seq_puts(s, "#                              | / _---=> hardirq/softirq\n");
+	seq_puts(s, "#                              || / _--=> preempt-depth\n");
+	seq_puts(s, "#                              ||| / _-=> migrate-disable     ");
+	seq_puts(s, "                    MAX\n");
+	seq_puts(s, "#                              |||| /     delay               ");
+	seq_puts(s, "                    SINGLE      Interference counters:\n");
+
+	seq_puts(s, "#                              |||||               RUNTIME   ");
+	seq_puts(s, "   NOISE  %% OF CPU  NOISE    +-----------------------------+\n");
+
+	seq_puts(s, "#           TASK-PID      CPU# |||||   TIMESTAMP    IN US    ");
+	seq_puts(s, "   IN US  AVAILABLE  IN US     HW    NMI    IRQ   SIRQ THREAD\n");
+
+	seq_puts(s, "#              | |         |   |||||      |           |      ");
+	seq_puts(s, "       |    |            |      |      |      |      |      |\n");
+}
+#endif /* CONFIG_PREEMPT_RT */
+
+/*
+ * osnoise_taint - report an osnoise error.
+ */
+#define osnoise_taint(msg) ({							\
+	struct osnoise_instance *inst;						\
+	struct trace_buffer *buffer;						\
+										\
+	rcu_read_lock();							\
+	list_for_each_entry_rcu(inst, &osnoise_instances, list) {		\
+		buffer = inst->tr->array_buffer.buffer;				\
+		trace_array_printk_buf(buffer, _THIS_IP_, msg);			\
+	}									\
+	rcu_read_unlock();							\
+	osnoise_data.tainted = true;						\
+})
+
+/*
+ * Record an osnoise_sample into the tracer buffer.
+ */
+static void
+__trace_osnoise_sample(struct osnoise_sample *sample, struct trace_buffer *buffer)
+{
+	struct trace_event_call *call = &event_osnoise;
+	struct ring_buffer_event *event;
+	struct osnoise_entry *entry;
+
+	event = trace_buffer_lock_reserve(buffer, TRACE_OSNOISE, sizeof(*entry),
+					  tracing_gen_ctx());
+	if (!event)
+		return;
+	entry	= ring_buffer_event_data(event);
+	entry->runtime		= sample->runtime;
+	entry->noise		= sample->noise;
+	entry->max_sample	= sample->max_sample;
+	entry->hw_count		= sample->hw_count;
+	entry->nmi_count	= sample->nmi_count;
+	entry->irq_count	= sample->irq_count;
+	entry->softirq_count	= sample->softirq_count;
+	entry->thread_count	= sample->thread_count;
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit_nostack(buffer, event);
+}
+
+/*
+ * Record an osnoise_sample on all osnoise instances.
+ */
+static void trace_osnoise_sample(struct osnoise_sample *sample)
+{
+	struct osnoise_instance *inst;
+	struct trace_buffer *buffer;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(inst, &osnoise_instances, list) {
+		buffer = inst->tr->array_buffer.buffer;
+		__trace_osnoise_sample(sample, buffer);
+	}
+	rcu_read_unlock();
+}
+
+#ifdef CONFIG_TIMERLAT_TRACER
+/*
+ * Print the timerlat header info.
+ */
+#ifdef CONFIG_PREEMPT_RT
+static void print_timerlat_headers(struct seq_file *s)
+{
+	seq_puts(s, "#                                _-------=> irqs-off\n");
+	seq_puts(s, "#                               / _------=> need-resched\n");
+	seq_puts(s, "#                              | / _-----=> need-resched-lazy\n");
+	seq_puts(s, "#                              || / _----=> hardirq/softirq\n");
+	seq_puts(s, "#                              ||| / _---=> preempt-depth\n");
+	seq_puts(s, "#                              |||| / _--=> preempt-lazy-depth\n");
+	seq_puts(s, "#                              ||||| / _-=> migrate-disable\n");
+	seq_puts(s, "#                              |||||| /\n");
+	seq_puts(s, "#                              |||||||             ACTIVATION\n");
+	seq_puts(s, "#           TASK-PID      CPU# |||||||   TIMESTAMP    ID     ");
+	seq_puts(s, "       CONTEXT                LATENCY\n");
+	seq_puts(s, "#              | |         |   |||||||      |         |      ");
+	seq_puts(s, "            |                       |\n");
+}
+#else /* CONFIG_PREEMPT_RT */
+static void print_timerlat_headers(struct seq_file *s)
+{
+	seq_puts(s, "#                                _-----=> irqs-off\n");
+	seq_puts(s, "#                               / _----=> need-resched\n");
+	seq_puts(s, "#                              | / _---=> hardirq/softirq\n");
+	seq_puts(s, "#                              || / _--=> preempt-depth\n");
+	seq_puts(s, "#                              ||| / _-=> migrate-disable\n");
+	seq_puts(s, "#                              |||| /     delay\n");
+	seq_puts(s, "#                              |||||            ACTIVATION\n");
+	seq_puts(s, "#           TASK-PID      CPU# |||||   TIMESTAMP   ID      ");
+	seq_puts(s, "      CONTEXT                 LATENCY\n");
+	seq_puts(s, "#              | |         |   |||||      |         |      ");
+	seq_puts(s, "            |                       |\n");
+}
+#endif /* CONFIG_PREEMPT_RT */
+
+static void
+__trace_timerlat_sample(struct timerlat_sample *sample, struct trace_buffer *buffer)
+{
+	struct trace_event_call *call = &event_osnoise;
+	struct ring_buffer_event *event;
+	struct timerlat_entry *entry;
+
+	event = trace_buffer_lock_reserve(buffer, TRACE_TIMERLAT, sizeof(*entry),
+					  tracing_gen_ctx());
+	if (!event)
+		return;
+	entry	= ring_buffer_event_data(event);
+	entry->seqnum			= sample->seqnum;
+	entry->context			= sample->context;
+	entry->timer_latency		= sample->timer_latency;
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit_nostack(buffer, event);
+}
+
+/*
+ * Record an timerlat_sample into the tracer buffer.
+ */
+static void trace_timerlat_sample(struct timerlat_sample *sample)
+{
+	struct osnoise_instance *inst;
+	struct trace_buffer *buffer;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(inst, &osnoise_instances, list) {
+		buffer = inst->tr->array_buffer.buffer;
+		__trace_timerlat_sample(sample, buffer);
+	}
+	rcu_read_unlock();
+}
+
+#ifdef CONFIG_STACKTRACE
+
+#define	MAX_CALLS	256
+
+/*
+ * Stack trace will take place only at IRQ level, so, no need
+ * to control nesting here.
+ */
+struct trace_stack {
+	int		stack_size;
+	int		nr_entries;
+	unsigned long	calls[MAX_CALLS];
+};
+
+static DEFINE_PER_CPU(struct trace_stack, trace_stack);
+
+/*
+ * timerlat_save_stack - save a stack trace without printing
+ *
+ * Save the current stack trace without printing. The
+ * stack will be printed later, after the end of the measurement.
+ */
+static void timerlat_save_stack(int skip)
+{
+	unsigned int size, nr_entries;
+	struct trace_stack *fstack;
+
+	fstack = this_cpu_ptr(&trace_stack);
+
+	size = ARRAY_SIZE(fstack->calls);
+
+	nr_entries = stack_trace_save(fstack->calls, size, skip);
+
+	fstack->stack_size = nr_entries * sizeof(unsigned long);
+	fstack->nr_entries = nr_entries;
+
+	return;
+
+}
+
+static void
+__timerlat_dump_stack(struct trace_buffer *buffer, struct trace_stack *fstack, unsigned int size)
+{
+	struct trace_event_call *call = &event_osnoise;
+	struct ring_buffer_event *event;
+	struct stack_entry *entry;
+
+	event = trace_buffer_lock_reserve(buffer, TRACE_STACK, sizeof(*entry) + size,
+					  tracing_gen_ctx());
+	if (!event)
+		return;
+
+	entry = ring_buffer_event_data(event);
+
+	memcpy(&entry->caller, fstack->calls, size);
+	entry->size = fstack->nr_entries;
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit_nostack(buffer, event);
+}
+
+/*
+ * timerlat_dump_stack - dump a stack trace previously saved
+ */
+static void timerlat_dump_stack(u64 latency)
+{
+	struct osnoise_instance *inst;
+	struct trace_buffer *buffer;
+	struct trace_stack *fstack;
+	unsigned int size;
+
+	/*
+	 * trace only if latency > print_stack config, if enabled.
+	 */
+	if (!osnoise_data.print_stack || osnoise_data.print_stack > latency)
+		return;
+
+	preempt_disable_notrace();
+	fstack = this_cpu_ptr(&trace_stack);
+	size = fstack->stack_size;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(inst, &osnoise_instances, list) {
+		buffer = inst->tr->array_buffer.buffer;
+		__timerlat_dump_stack(buffer, fstack, size);
+
+	}
+	rcu_read_unlock();
+	preempt_enable_notrace();
+}
+#else /* CONFIG_STACKTRACE */
+#define timerlat_dump_stack(u64 latency) do {} while (0)
+#define timerlat_save_stack(a) do {} while (0)
+#endif /* CONFIG_STACKTRACE */
+#endif /* CONFIG_TIMERLAT_TRACER */
+
+/*
+ * Macros to encapsulate the time capturing infrastructure.
+ */
+#define time_get()	trace_clock_local()
+#define time_to_us(x)	div_u64(x, 1000)
+#define time_sub(a, b)	((a) - (b))
+
+/*
+ * cond_move_irq_delta_start - Forward the delta_start of a running IRQ
+ *
+ * If an IRQ is preempted by an NMI, its delta_start is pushed forward
+ * to discount the NMI interference.
+ *
+ * See get_int_safe_duration().
+ */
+static inline void
+cond_move_irq_delta_start(struct osnoise_variables *osn_var, u64 duration)
+{
+	if (osn_var->irq.delta_start)
+		osn_var->irq.delta_start += duration;
+}
+
+#ifndef CONFIG_PREEMPT_RT
+/*
+ * cond_move_softirq_delta_start - Forward the delta_start of a running softirq.
+ *
+ * If a softirq is preempted by an IRQ or NMI, its delta_start is pushed
+ * forward to discount the interference.
+ *
+ * See get_int_safe_duration().
+ */
+static inline void
+cond_move_softirq_delta_start(struct osnoise_variables *osn_var, u64 duration)
+{
+	if (osn_var->softirq.delta_start)
+		osn_var->softirq.delta_start += duration;
+}
+#else /* CONFIG_PREEMPT_RT */
+#define cond_move_softirq_delta_start(osn_var, duration) do {} while (0)
+#endif
+
+/*
+ * cond_move_thread_delta_start - Forward the delta_start of a running thread
+ *
+ * If a noisy thread is preempted by an softirq, IRQ or NMI, its delta_start
+ * is pushed forward to discount the interference.
+ *
+ * See get_int_safe_duration().
+ */
+static inline void
+cond_move_thread_delta_start(struct osnoise_variables *osn_var, u64 duration)
+{
+	if (osn_var->thread.delta_start)
+		osn_var->thread.delta_start += duration;
+}
+
+/*
+ * get_int_safe_duration - Get the duration of a window
+ *
+ * The irq, softirq and thread varaibles need to have its duration without
+ * the interference from higher priority interrupts. Instead of keeping a
+ * variable to discount the interrupt interference from these variables, the
+ * starting time of these variables are pushed forward with the interrupt's
+ * duration. In this way, a single variable is used to:
+ *
+ *   - Know if a given window is being measured.
+ *   - Account its duration.
+ *   - Discount the interference.
+ *
+ * To avoid getting inconsistent values, e.g.,:
+ *
+ *	now = time_get()
+ *		--->	interrupt!
+ *			delta_start -= int duration;
+ *		<---
+ *	duration = now - delta_start;
+ *
+ *	result: negative duration if the variable duration before the
+ *	interrupt was smaller than the interrupt execution.
+ *
+ * A counter of interrupts is used. If the counter increased, try
+ * to capture an interference safe duration.
+ */
+static inline s64
+get_int_safe_duration(struct osnoise_variables *osn_var, u64 *delta_start)
+{
+	u64 int_counter, now;
+	s64 duration;
+
+	do {
+		int_counter = local_read(&osn_var->int_counter);
+		/* synchronize with interrupts */
+		barrier();
+
+		now = time_get();
+		duration = (now - *delta_start);
+
+		/* synchronize with interrupts */
+		barrier();
+	} while (int_counter != local_read(&osn_var->int_counter));
+
+	/*
+	 * This is an evidence of race conditions that cause
+	 * a value to be "discounted" too much.
+	 */
+	if (duration < 0)
+		osnoise_taint("Negative duration!\n");
+
+	*delta_start = 0;
+
+	return duration;
+}
+
+/*
+ *
+ * set_int_safe_time - Save the current time on *time, aware of interference
+ *
+ * Get the time, taking into consideration a possible interference from
+ * higher priority interrupts.
+ *
+ * See get_int_safe_duration() for an explanation.
+ */
+static u64
+set_int_safe_time(struct osnoise_variables *osn_var, u64 *time)
+{
+	u64 int_counter;
+
+	do {
+		int_counter = local_read(&osn_var->int_counter);
+		/* synchronize with interrupts */
+		barrier();
+
+		*time = time_get();
+
+		/* synchronize with interrupts */
+		barrier();
+	} while (int_counter != local_read(&osn_var->int_counter));
+
+	return int_counter;
+}
+
+#ifdef CONFIG_TIMERLAT_TRACER
+/*
+ * copy_int_safe_time - Copy *src into *desc aware of interference
+ */
+static u64
+copy_int_safe_time(struct osnoise_variables *osn_var, u64 *dst, u64 *src)
+{
+	u64 int_counter;
+
+	do {
+		int_counter = local_read(&osn_var->int_counter);
+		/* synchronize with interrupts */
+		barrier();
+
+		*dst = *src;
+
+		/* synchronize with interrupts */
+		barrier();
+	} while (int_counter != local_read(&osn_var->int_counter));
+
+	return int_counter;
+}
+#endif /* CONFIG_TIMERLAT_TRACER */
+
+/*
+ * trace_osnoise_callback - NMI entry/exit callback
+ *
+ * This function is called at the entry and exit NMI code. The bool enter
+ * distinguishes between either case. This function is used to note a NMI
+ * occurrence, compute the noise caused by the NMI, and to remove the noise
+ * it is potentially causing on other interference variables.
+ */
+void trace_osnoise_callback(bool enter)
+{
+	struct osnoise_variables *osn_var = this_cpu_osn_var();
+	u64 duration;
+
+	if (!osn_var->sampling)
+		return;
+
+	/*
+	 * Currently trace_clock_local() calls sched_clock() and the
+	 * generic version is not NMI safe.
+	 */
+	if (!IS_ENABLED(CONFIG_GENERIC_SCHED_CLOCK)) {
+		if (enter) {
+			osn_var->nmi.delta_start = time_get();
+			local_inc(&osn_var->int_counter);
+		} else {
+			duration = time_get() - osn_var->nmi.delta_start;
+
+			trace_nmi_noise(osn_var->nmi.delta_start, duration);
+
+			cond_move_irq_delta_start(osn_var, duration);
+			cond_move_softirq_delta_start(osn_var, duration);
+			cond_move_thread_delta_start(osn_var, duration);
+		}
+	}
+
+	if (enter)
+		osn_var->nmi.count++;
+}
+
+/*
+ * osnoise_trace_irq_entry - Note the starting of an IRQ
+ *
+ * Save the starting time of an IRQ. As IRQs are non-preemptive to other IRQs,
+ * it is safe to use a single variable (ons_var->irq) to save the statistics.
+ * The arrival_time is used to report... the arrival time. The delta_start
+ * is used to compute the duration at the IRQ exit handler. See
+ * cond_move_irq_delta_start().
+ */
+void osnoise_trace_irq_entry(int id)
+{
+	struct osnoise_variables *osn_var = this_cpu_osn_var();
+
+	if (!osn_var->sampling)
+		return;
+	/*
+	 * This value will be used in the report, but not to compute
+	 * the execution time, so it is safe to get it unsafe.
+	 */
+	osn_var->irq.arrival_time = time_get();
+	set_int_safe_time(osn_var, &osn_var->irq.delta_start);
+	osn_var->irq.count++;
+
+	local_inc(&osn_var->int_counter);
+}
+
+/*
+ * osnoise_irq_exit - Note the end of an IRQ, sava data and trace
+ *
+ * Computes the duration of the IRQ noise, and trace it. Also discounts the
+ * interference from other sources of noise could be currently being accounted.
+ */
+void osnoise_trace_irq_exit(int id, const char *desc)
+{
+	struct osnoise_variables *osn_var = this_cpu_osn_var();
+	s64 duration;
+
+	if (!osn_var->sampling)
+		return;
+
+	duration = get_int_safe_duration(osn_var, &osn_var->irq.delta_start);
+	trace_irq_noise(id, desc, osn_var->irq.arrival_time, duration);
+	osn_var->irq.arrival_time = 0;
+	cond_move_softirq_delta_start(osn_var, duration);
+	cond_move_thread_delta_start(osn_var, duration);
+}
+
+/*
+ * trace_irqentry_callback - Callback to the irq:irq_entry traceevent
+ *
+ * Used to note the starting of an IRQ occurece.
+ */
+static void trace_irqentry_callback(void *data, int irq,
+				    struct irqaction *action)
+{
+	osnoise_trace_irq_entry(irq);
+}
+
+/*
+ * trace_irqexit_callback - Callback to the irq:irq_exit traceevent
+ *
+ * Used to note the end of an IRQ occurece.
+ */
+static void trace_irqexit_callback(void *data, int irq,
+				   struct irqaction *action, int ret)
+{
+	osnoise_trace_irq_exit(irq, action->name);
+}
+
+/*
+ * arch specific register function.
+ */
+int __weak osnoise_arch_register(void)
+{
+	return 0;
+}
+
+/*
+ * arch specific unregister function.
+ */
+void __weak osnoise_arch_unregister(void)
+{
+	return;
+}
+
+/*
+ * hook_irq_events - Hook IRQ handling events
+ *
+ * This function hooks the IRQ related callbacks to the respective trace
+ * events.
+ */
+static int hook_irq_events(void)
+{
+	int ret;
+
+	ret = register_trace_irq_handler_entry(trace_irqentry_callback, NULL);
+	if (ret)
+		goto out_err;
+
+	ret = register_trace_irq_handler_exit(trace_irqexit_callback, NULL);
+	if (ret)
+		goto out_unregister_entry;
+
+	ret = osnoise_arch_register();
+	if (ret)
+		goto out_irq_exit;
+
+	return 0;
+
+out_irq_exit:
+	unregister_trace_irq_handler_exit(trace_irqexit_callback, NULL);
+out_unregister_entry:
+	unregister_trace_irq_handler_entry(trace_irqentry_callback, NULL);
+out_err:
+	return -EINVAL;
+}
+
+/*
+ * unhook_irq_events - Unhook IRQ handling events
+ *
+ * This function unhooks the IRQ related callbacks to the respective trace
+ * events.
+ */
+static void unhook_irq_events(void)
+{
+	osnoise_arch_unregister();
+	unregister_trace_irq_handler_exit(trace_irqexit_callback, NULL);
+	unregister_trace_irq_handler_entry(trace_irqentry_callback, NULL);
+}
+
+#ifndef CONFIG_PREEMPT_RT
+/*
+ * trace_softirq_entry_callback - Note the starting of a softirq
+ *
+ * Save the starting time of a softirq. As softirqs are non-preemptive to
+ * other softirqs, it is safe to use a single variable (ons_var->softirq)
+ * to save the statistics. The arrival_time is used to report... the
+ * arrival time. The delta_start is used to compute the duration at the
+ * softirq exit handler. See cond_move_softirq_delta_start().
+ */
+static void trace_softirq_entry_callback(void *data, unsigned int vec_nr)
+{
+	struct osnoise_variables *osn_var = this_cpu_osn_var();
+
+	if (!osn_var->sampling)
+		return;
+	/*
+	 * This value will be used in the report, but not to compute
+	 * the execution time, so it is safe to get it unsafe.
+	 */
+	osn_var->softirq.arrival_time = time_get();
+	set_int_safe_time(osn_var, &osn_var->softirq.delta_start);
+	osn_var->softirq.count++;
+
+	local_inc(&osn_var->int_counter);
+}
+
+/*
+ * trace_softirq_exit_callback - Note the end of an softirq
+ *
+ * Computes the duration of the softirq noise, and trace it. Also discounts the
+ * interference from other sources of noise could be currently being accounted.
+ */
+static void trace_softirq_exit_callback(void *data, unsigned int vec_nr)
+{
+	struct osnoise_variables *osn_var = this_cpu_osn_var();
+	s64 duration;
+
+	if (!osn_var->sampling)
+		return;
+
+	if (unlikely(timerlat_enabled()))
+		if (!timerlat_softirq_exit(osn_var))
+			return;
+
+	duration = get_int_safe_duration(osn_var, &osn_var->softirq.delta_start);
+	trace_softirq_noise(vec_nr, osn_var->softirq.arrival_time, duration);
+	cond_move_thread_delta_start(osn_var, duration);
+	osn_var->softirq.arrival_time = 0;
+}
+
+/*
+ * hook_softirq_events - Hook softirq handling events
+ *
+ * This function hooks the softirq related callbacks to the respective trace
+ * events.
+ */
+static int hook_softirq_events(void)
+{
+	int ret;
+
+	ret = register_trace_softirq_entry(trace_softirq_entry_callback, NULL);
+	if (ret)
+		goto out_err;
+
+	ret = register_trace_softirq_exit(trace_softirq_exit_callback, NULL);
+	if (ret)
+		goto out_unreg_entry;
+
+	return 0;
+
+out_unreg_entry:
+	unregister_trace_softirq_entry(trace_softirq_entry_callback, NULL);
+out_err:
+	return -EINVAL;
+}
+
+/*
+ * unhook_softirq_events - Unhook softirq handling events
+ *
+ * This function hooks the softirq related callbacks to the respective trace
+ * events.
+ */
+static void unhook_softirq_events(void)
+{
+	unregister_trace_softirq_entry(trace_softirq_entry_callback, NULL);
+	unregister_trace_softirq_exit(trace_softirq_exit_callback, NULL);
+}
+#else /* CONFIG_PREEMPT_RT */
+/*
+ * softirq are threads on the PREEMPT_RT mode.
+ */
+static int hook_softirq_events(void)
+{
+	return 0;
+}
+static void unhook_softirq_events(void)
+{
+}
+#endif
+
+/*
+ * thread_entry - Record the starting of a thread noise window
+ *
+ * It saves the context switch time for a noisy thread, and increments
+ * the interference counters.
+ */
+static void
+thread_entry(struct osnoise_variables *osn_var, struct task_struct *t)
+{
+	if (!osn_var->sampling)
+		return;
+	/*
+	 * The arrival time will be used in the report, but not to compute
+	 * the execution time, so it is safe to get it unsafe.
+	 */
+	osn_var->thread.arrival_time = time_get();
+
+	set_int_safe_time(osn_var, &osn_var->thread.delta_start);
+
+	osn_var->thread.count++;
+	local_inc(&osn_var->int_counter);
+}
+
+/*
+ * thread_exit - Report the end of a thread noise window
+ *
+ * It computes the total noise from a thread, tracing if needed.
+ */
+static void
+thread_exit(struct osnoise_variables *osn_var, struct task_struct *t)
+{
+	s64 duration;
+
+	if (!osn_var->sampling)
+		return;
+
+	if (unlikely(timerlat_enabled()))
+		if (!timerlat_thread_exit(osn_var))
+			return;
+
+	duration = get_int_safe_duration(osn_var, &osn_var->thread.delta_start);
+
+	trace_thread_noise(t, osn_var->thread.arrival_time, duration);
+
+	osn_var->thread.arrival_time = 0;
+}
+
+/*
+ * trace_sched_switch - sched:sched_switch trace event handler
+ *
+ * This function is hooked to the sched:sched_switch trace event, and it is
+ * used to record the beginning and to report the end of a thread noise window.
+ */
+static void
+trace_sched_switch_callback(void *data, bool preempt,
+			    struct task_struct *p,
+			    struct task_struct *n,
+			    unsigned int prev_state)
+{
+	struct osnoise_variables *osn_var = this_cpu_osn_var();
+
+	if (p->pid != osn_var->pid)
+		thread_exit(osn_var, p);
+
+	if (n->pid != osn_var->pid)
+		thread_entry(osn_var, n);
+}
+
+/*
+ * hook_thread_events - Hook the insturmentation for thread noise
+ *
+ * Hook the osnoise tracer callbacks to handle the noise from other
+ * threads on the necessary kernel events.
+ */
+static int hook_thread_events(void)
+{
+	int ret;
+
+	ret = register_trace_sched_switch(trace_sched_switch_callback, NULL);
+	if (ret)
+		return -EINVAL;
+
+	return 0;
+}
+
+/*
+ * unhook_thread_events - *nhook the insturmentation for thread noise
+ *
+ * Unook the osnoise tracer callbacks to handle the noise from other
+ * threads on the necessary kernel events.
+ */
+static void unhook_thread_events(void)
+{
+	unregister_trace_sched_switch(trace_sched_switch_callback, NULL);
+}
+
+/*
+ * save_osn_sample_stats - Save the osnoise_sample statistics
+ *
+ * Save the osnoise_sample statistics before the sampling phase. These
+ * values will be used later to compute the diff betwneen the statistics
+ * before and after the osnoise sampling.
+ */
+static void
+save_osn_sample_stats(struct osnoise_variables *osn_var, struct osnoise_sample *s)
+{
+	s->nmi_count = osn_var->nmi.count;
+	s->irq_count = osn_var->irq.count;
+	s->softirq_count = osn_var->softirq.count;
+	s->thread_count = osn_var->thread.count;
+}
+
+/*
+ * diff_osn_sample_stats - Compute the osnoise_sample statistics
+ *
+ * After a sample period, compute the difference on the osnoise_sample
+ * statistics. The struct osnoise_sample *s contains the statistics saved via
+ * save_osn_sample_stats() before the osnoise sampling.
+ */
+static void
+diff_osn_sample_stats(struct osnoise_variables *osn_var, struct osnoise_sample *s)
+{
+	s->nmi_count = osn_var->nmi.count - s->nmi_count;
+	s->irq_count = osn_var->irq.count - s->irq_count;
+	s->softirq_count = osn_var->softirq.count - s->softirq_count;
+	s->thread_count = osn_var->thread.count - s->thread_count;
+}
+
+/*
+ * osnoise_stop_tracing - Stop tracing and the tracer.
+ */
+static __always_inline void osnoise_stop_tracing(void)
+{
+	struct osnoise_instance *inst;
+	struct trace_array *tr;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(inst, &osnoise_instances, list) {
+		tr = inst->tr;
+		trace_array_printk_buf(tr->array_buffer.buffer, _THIS_IP_,
+				"stop tracing hit on cpu %d\n", smp_processor_id());
+
+		tracer_tracing_off(tr);
+	}
+	rcu_read_unlock();
+}
+
+/*
+ * notify_new_max_latency - Notify a new max latency via fsnotify interface.
+ */
+static void notify_new_max_latency(u64 latency)
+{
+	struct osnoise_instance *inst;
+	struct trace_array *tr;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(inst, &osnoise_instances, list) {
+		tr = inst->tr;
+		if (tracer_tracing_is_on(tr) && tr->max_latency < latency) {
+			tr->max_latency = latency;
+			latency_fsnotify(tr);
+		}
+	}
+	rcu_read_unlock();
+}
+
+/*
+ * run_osnoise - Sample the time and look for osnoise
+ *
+ * Used to capture the time, looking for potential osnoise latency repeatedly.
+ * Different from hwlat_detector, it is called with preemption and interrupts
+ * enabled. This allows irqs, softirqs and threads to run, interfering on the
+ * osnoise sampling thread, as they would do with a regular thread.
+ */
+static int run_osnoise(void)
+{
+	struct osnoise_variables *osn_var = this_cpu_osn_var();
+	u64 start, sample, last_sample;
+	u64 last_int_count, int_count;
+	s64 noise = 0, max_noise = 0;
+	s64 total, last_total = 0;
+	struct osnoise_sample s;
+	unsigned int threshold;
+	u64 runtime, stop_in;
+	u64 sum_noise = 0;
+	int hw_count = 0;
+	int ret = -1;
+
+	/*
+	 * Considers the current thread as the workload.
+	 */
+	osn_var->pid = current->pid;
+
+	/*
+	 * Save the current stats for the diff
+	 */
+	save_osn_sample_stats(osn_var, &s);
+
+	/*
+	 * if threshold is 0, use the default value of 5 us.
+	 */
+	threshold = tracing_thresh ? : 5000;
+
+	/*
+	 * Make sure NMIs see sampling first
+	 */
+	osn_var->sampling = true;
+	barrier();
+
+	/*
+	 * Transform the *_us config to nanoseconds to avoid the
+	 * division on the main loop.
+	 */
+	runtime = osnoise_data.sample_runtime * NSEC_PER_USEC;
+	stop_in = osnoise_data.stop_tracing * NSEC_PER_USEC;
+
+	/*
+	 * Start timestemp
+	 */
+	start = time_get();
+
+	/*
+	 * "previous" loop.
+	 */
+	last_int_count = set_int_safe_time(osn_var, &last_sample);
+
+	do {
+		/*
+		 * Get sample!
+		 */
+		int_count = set_int_safe_time(osn_var, &sample);
+
+		noise = time_sub(sample, last_sample);
+
+		/*
+		 * This shouldn't happen.
+		 */
+		if (noise < 0) {
+			osnoise_taint("negative noise!");
+			goto out;
+		}
+
+		/*
+		 * Sample runtime.
+		 */
+		total = time_sub(sample, start);
+
+		/*
+		 * Check for possible overflows.
+		 */
+		if (total < last_total) {
+			osnoise_taint("total overflow!");
+			break;
+		}
+
+		last_total = total;
+
+		if (noise >= threshold) {
+			int interference = int_count - last_int_count;
+
+			if (noise > max_noise)
+				max_noise = noise;
+
+			if (!interference)
+				hw_count++;
+
+			sum_noise += noise;
+
+			trace_sample_threshold(last_sample, noise, interference);
+
+			if (osnoise_data.stop_tracing)
+				if (noise > stop_in)
+					osnoise_stop_tracing();
+		}
+
+		/*
+		 * In some cases, notably when running on a nohz_full CPU with
+		 * a stopped tick PREEMPT_RCU has no way to account for QSs.
+		 * This will eventually cause unwarranted noise as PREEMPT_RCU
+		 * will force preemption as the means of ending the current
+		 * grace period. We avoid this problem by calling
+		 * rcu_momentary_dyntick_idle(), which performs a zero duration
+		 * EQS allowing PREEMPT_RCU to end the current grace period.
+		 * This call shouldn't be wrapped inside an RCU critical
+		 * section.
+		 *
+		 * Note that in non PREEMPT_RCU kernels QSs are handled through
+		 * cond_resched()
+		 */
+		if (IS_ENABLED(CONFIG_PREEMPT_RCU)) {
+			local_irq_disable();
+			rcu_momentary_dyntick_idle();
+			local_irq_enable();
+		}
+
+		/*
+		 * For the non-preemptive kernel config: let threads runs, if
+		 * they so wish.
+		 */
+		cond_resched();
+
+		last_sample = sample;
+		last_int_count = int_count;
+
+	} while (total < runtime && !kthread_should_stop());
+
+	/*
+	 * Finish the above in the view for interrupts.
+	 */
+	barrier();
+
+	osn_var->sampling = false;
+
+	/*
+	 * Make sure sampling data is no longer updated.
+	 */
+	barrier();
+
+	/*
+	 * Save noise info.
+	 */
+	s.noise = time_to_us(sum_noise);
+	s.runtime = time_to_us(total);
+	s.max_sample = time_to_us(max_noise);
+	s.hw_count = hw_count;
+
+	/* Save interference stats info */
+	diff_osn_sample_stats(osn_var, &s);
+
+	trace_osnoise_sample(&s);
+
+	notify_new_max_latency(max_noise);
+
+	if (osnoise_data.stop_tracing_total)
+		if (s.noise > osnoise_data.stop_tracing_total)
+			osnoise_stop_tracing();
+
+	return 0;
+out:
+	return ret;
+}
+
+static struct cpumask osnoise_cpumask;
+static struct cpumask save_cpumask;
+
+/*
+ * osnoise_sleep - sleep until the next period
+ */
+static void osnoise_sleep(void)
+{
+	u64 interval;
+	ktime_t wake_time;
+
+	mutex_lock(&interface_lock);
+	interval = osnoise_data.sample_period - osnoise_data.sample_runtime;
+	mutex_unlock(&interface_lock);
+
+	/*
+	 * differently from hwlat_detector, the osnoise tracer can run
+	 * without a pause because preemption is on.
+	 */
+	if (!interval) {
+		/* Let synchronize_rcu_tasks() make progress */
+		cond_resched_tasks_rcu_qs();
+		return;
+	}
+
+	wake_time = ktime_add_us(ktime_get(), interval);
+	__set_current_state(TASK_INTERRUPTIBLE);
+
+	while (schedule_hrtimeout_range(&wake_time, 0, HRTIMER_MODE_ABS)) {
+		if (kthread_should_stop())
+			break;
+	}
+}
+
+/*
+ * osnoise_main - The osnoise detection kernel thread
+ *
+ * Calls run_osnoise() function to measure the osnoise for the configured runtime,
+ * every period.
+ */
+static int osnoise_main(void *data)
+{
+
+	while (!kthread_should_stop()) {
+		run_osnoise();
+		osnoise_sleep();
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_TIMERLAT_TRACER
+/*
+ * timerlat_irq - hrtimer handler for timerlat.
+ */
+static enum hrtimer_restart timerlat_irq(struct hrtimer *timer)
+{
+	struct osnoise_variables *osn_var = this_cpu_osn_var();
+	struct timerlat_variables *tlat;
+	struct timerlat_sample s;
+	u64 now;
+	u64 diff;
+
+	/*
+	 * I am not sure if the timer was armed for this CPU. So, get
+	 * the timerlat struct from the timer itself, not from this
+	 * CPU.
+	 */
+	tlat = container_of(timer, struct timerlat_variables, timer);
+
+	now = ktime_to_ns(hrtimer_cb_get_time(&tlat->timer));
+
+	/*
+	 * Enable the osnoise: events for thread an softirq.
+	 */
+	tlat->tracing_thread = true;
+
+	osn_var->thread.arrival_time = time_get();
+
+	/*
+	 * A hardirq is running: the timer IRQ. It is for sure preempting
+	 * a thread, and potentially preempting a softirq.
+	 *
+	 * At this point, it is not interesting to know the duration of the
+	 * preempted thread (and maybe softirq), but how much time they will
+	 * delay the beginning of the execution of the timer thread.
+	 *
+	 * To get the correct (net) delay added by the softirq, its delta_start
+	 * is set as the IRQ one. In this way, at the return of the IRQ, the delta
+	 * start of the sofitrq will be zeroed, accounting then only the time
+	 * after that.
+	 *
+	 * The thread follows the same principle. However, if a softirq is
+	 * running, the thread needs to receive the softirq delta_start. The
+	 * reason being is that the softirq will be the last to be unfolded,
+	 * resseting the thread delay to zero.
+	 *
+	 * The PREEMPT_RT is a special case, though. As softirqs run as threads
+	 * on RT, moving the thread is enough.
+	 */
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT) && osn_var->softirq.delta_start) {
+		copy_int_safe_time(osn_var, &osn_var->thread.delta_start,
+				   &osn_var->softirq.delta_start);
+
+		copy_int_safe_time(osn_var, &osn_var->softirq.delta_start,
+				    &osn_var->irq.delta_start);
+	} else {
+		copy_int_safe_time(osn_var, &osn_var->thread.delta_start,
+				    &osn_var->irq.delta_start);
+	}
+
+	/*
+	 * Compute the current time with the expected time.
+	 */
+	diff = now - tlat->abs_period;
+
+	tlat->count++;
+	s.seqnum = tlat->count;
+	s.timer_latency = diff;
+	s.context = IRQ_CONTEXT;
+
+	trace_timerlat_sample(&s);
+
+	if (osnoise_data.stop_tracing) {
+		if (time_to_us(diff) >= osnoise_data.stop_tracing) {
+
+			/*
+			 * At this point, if stop_tracing is set and <= print_stack,
+			 * print_stack is set and would be printed in the thread handler.
+			 *
+			 * Thus, print the stack trace as it is helpful to define the
+			 * root cause of an IRQ latency.
+			 */
+			if (osnoise_data.stop_tracing <= osnoise_data.print_stack) {
+				timerlat_save_stack(0);
+				timerlat_dump_stack(time_to_us(diff));
+			}
+
+			osnoise_stop_tracing();
+			notify_new_max_latency(diff);
+
+			wake_up_process(tlat->kthread);
+
+			return HRTIMER_NORESTART;
+		}
+	}
+
+	wake_up_process(tlat->kthread);
+
+	if (osnoise_data.print_stack)
+		timerlat_save_stack(0);
+
+	return HRTIMER_NORESTART;
+}
+
+/*
+ * wait_next_period - Wait for the next period for timerlat
+ */
+static int wait_next_period(struct timerlat_variables *tlat)
+{
+	ktime_t next_abs_period, now;
+	u64 rel_period = osnoise_data.timerlat_period * 1000;
+
+	now = hrtimer_cb_get_time(&tlat->timer);
+	next_abs_period = ns_to_ktime(tlat->abs_period + rel_period);
+
+	/*
+	 * Save the next abs_period.
+	 */
+	tlat->abs_period = (u64) ktime_to_ns(next_abs_period);
+
+	/*
+	 * If the new abs_period is in the past, skip the activation.
+	 */
+	while (ktime_compare(now, next_abs_period) > 0) {
+		next_abs_period = ns_to_ktime(tlat->abs_period + rel_period);
+		tlat->abs_period = (u64) ktime_to_ns(next_abs_period);
+	}
+
+	set_current_state(TASK_INTERRUPTIBLE);
+
+	hrtimer_start(&tlat->timer, next_abs_period, HRTIMER_MODE_ABS_PINNED_HARD);
+	schedule();
+	return 1;
+}
+
+/*
+ * timerlat_main- Timerlat main
+ */
+static int timerlat_main(void *data)
+{
+	struct osnoise_variables *osn_var = this_cpu_osn_var();
+	struct timerlat_variables *tlat = this_cpu_tmr_var();
+	struct timerlat_sample s;
+	struct sched_param sp;
+	u64 now, diff;
+
+	/*
+	 * Make the thread RT, that is how cyclictest is usually used.
+	 */
+	sp.sched_priority = DEFAULT_TIMERLAT_PRIO;
+	sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
+
+	tlat->count = 0;
+	tlat->tracing_thread = false;
+
+	hrtimer_init(&tlat->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
+	tlat->timer.function = timerlat_irq;
+	tlat->kthread = current;
+	osn_var->pid = current->pid;
+	/*
+	 * Anotate the arrival time.
+	 */
+	tlat->abs_period = hrtimer_cb_get_time(&tlat->timer);
+
+	wait_next_period(tlat);
+
+	osn_var->sampling = 1;
+
+	while (!kthread_should_stop()) {
+		now = ktime_to_ns(hrtimer_cb_get_time(&tlat->timer));
+		diff = now - tlat->abs_period;
+
+		s.seqnum = tlat->count;
+		s.timer_latency = diff;
+		s.context = THREAD_CONTEXT;
+
+		trace_timerlat_sample(&s);
+
+		notify_new_max_latency(diff);
+
+		timerlat_dump_stack(time_to_us(diff));
+
+		tlat->tracing_thread = false;
+		if (osnoise_data.stop_tracing_total)
+			if (time_to_us(diff) >= osnoise_data.stop_tracing_total)
+				osnoise_stop_tracing();
+
+		wait_next_period(tlat);
+	}
+
+	hrtimer_cancel(&tlat->timer);
+	return 0;
+}
+#else /* CONFIG_TIMERLAT_TRACER */
+static int timerlat_main(void *data)
+{
+	return 0;
+}
+#endif /* CONFIG_TIMERLAT_TRACER */
+
+/*
+ * stop_kthread - stop a workload thread
+ */
+static void stop_kthread(unsigned int cpu)
+{
+	struct task_struct *kthread;
+
+	kthread = per_cpu(per_cpu_osnoise_var, cpu).kthread;
+	if (kthread)
+		kthread_stop(kthread);
+	per_cpu(per_cpu_osnoise_var, cpu).kthread = NULL;
+}
+
+/*
+ * stop_per_cpu_kthread - Stop per-cpu threads
+ *
+ * Stop the osnoise sampling htread. Use this on unload and at system
+ * shutdown.
+ */
+static void stop_per_cpu_kthreads(void)
+{
+	int cpu;
+
+	cpus_read_lock();
+
+	for_each_online_cpu(cpu)
+		stop_kthread(cpu);
+
+	cpus_read_unlock();
+}
+
+/*
+ * start_kthread - Start a workload tread
+ */
+static int start_kthread(unsigned int cpu)
+{
+	struct task_struct *kthread;
+	void *main = osnoise_main;
+	char comm[24];
+
+	if (timerlat_enabled()) {
+		snprintf(comm, 24, "timerlat/%d", cpu);
+		main = timerlat_main;
+	} else {
+		snprintf(comm, 24, "osnoise/%d", cpu);
+	}
+
+	kthread = kthread_run_on_cpu(main, NULL, cpu, comm);
+
+	if (IS_ERR(kthread)) {
+		pr_err(BANNER "could not start sampling thread\n");
+		stop_per_cpu_kthreads();
+		return -ENOMEM;
+	}
+
+	per_cpu(per_cpu_osnoise_var, cpu).kthread = kthread;
+
+	return 0;
+}
+
+/*
+ * start_per_cpu_kthread - Kick off per-cpu osnoise sampling kthreads
+ *
+ * This starts the kernel thread that will look for osnoise on many
+ * cpus.
+ */
+static int start_per_cpu_kthreads(void)
+{
+	struct cpumask *current_mask = &save_cpumask;
+	int retval = 0;
+	int cpu;
+
+	cpus_read_lock();
+	/*
+	 * Run only on online CPUs in which osnoise is allowed to run.
+	 */
+	cpumask_and(current_mask, cpu_online_mask, &osnoise_cpumask);
+
+	for_each_possible_cpu(cpu)
+		per_cpu(per_cpu_osnoise_var, cpu).kthread = NULL;
+
+	for_each_cpu(cpu, current_mask) {
+		retval = start_kthread(cpu);
+		if (retval) {
+			cpus_read_unlock();
+			stop_per_cpu_kthreads();
+			return retval;
+		}
+	}
+
+	cpus_read_unlock();
+
+	return retval;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void osnoise_hotplug_workfn(struct work_struct *dummy)
+{
+	unsigned int cpu = smp_processor_id();
+
+	mutex_lock(&trace_types_lock);
+
+	if (!osnoise_has_registered_instances())
+		goto out_unlock_trace;
+
+	mutex_lock(&interface_lock);
+	cpus_read_lock();
+
+	if (!cpumask_test_cpu(cpu, &osnoise_cpumask))
+		goto out_unlock;
+
+	start_kthread(cpu);
+
+out_unlock:
+	cpus_read_unlock();
+	mutex_unlock(&interface_lock);
+out_unlock_trace:
+	mutex_unlock(&trace_types_lock);
+}
+
+static DECLARE_WORK(osnoise_hotplug_work, osnoise_hotplug_workfn);
+
+/*
+ * osnoise_cpu_init - CPU hotplug online callback function
+ */
+static int osnoise_cpu_init(unsigned int cpu)
+{
+	schedule_work_on(cpu, &osnoise_hotplug_work);
+	return 0;
+}
+
+/*
+ * osnoise_cpu_die - CPU hotplug offline callback function
+ */
+static int osnoise_cpu_die(unsigned int cpu)
+{
+	stop_kthread(cpu);
+	return 0;
+}
+
+static void osnoise_init_hotplug_support(void)
+{
+	int ret;
+
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "trace/osnoise:online",
+				osnoise_cpu_init, osnoise_cpu_die);
+	if (ret < 0)
+		pr_warn(BANNER "Error to init cpu hotplug support\n");
+
+	return;
+}
+#else /* CONFIG_HOTPLUG_CPU */
+static void osnoise_init_hotplug_support(void)
+{
+	return;
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
+/*
+ * osnoise_cpus_read - Read function for reading the "cpus" file
+ * @filp: The active open file structure
+ * @ubuf: The userspace provided buffer to read value into
+ * @cnt: The maximum number of bytes to read
+ * @ppos: The current "file" position
+ *
+ * Prints the "cpus" output into the user-provided buffer.
+ */
+static ssize_t
+osnoise_cpus_read(struct file *filp, char __user *ubuf, size_t count,
+		  loff_t *ppos)
+{
+	char *mask_str;
+	int len;
+
+	mutex_lock(&interface_lock);
+
+	len = snprintf(NULL, 0, "%*pbl\n", cpumask_pr_args(&osnoise_cpumask)) + 1;
+	mask_str = kmalloc(len, GFP_KERNEL);
+	if (!mask_str) {
+		count = -ENOMEM;
+		goto out_unlock;
+	}
+
+	len = snprintf(mask_str, len, "%*pbl\n", cpumask_pr_args(&osnoise_cpumask));
+	if (len >= count) {
+		count = -EINVAL;
+		goto out_free;
+	}
+
+	count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
+
+out_free:
+	kfree(mask_str);
+out_unlock:
+	mutex_unlock(&interface_lock);
+
+	return count;
+}
+
+/*
+ * osnoise_cpus_write - Write function for "cpus" entry
+ * @filp: The active open file structure
+ * @ubuf: The user buffer that contains the value to write
+ * @cnt: The maximum number of bytes to write to "file"
+ * @ppos: The current position in @file
+ *
+ * This function provides a write implementation for the "cpus"
+ * interface to the osnoise trace. By default, it lists all  CPUs,
+ * in this way, allowing osnoise threads to run on any online CPU
+ * of the system. It serves to restrict the execution of osnoise to the
+ * set of CPUs writing via this interface. Why not use "tracing_cpumask"?
+ * Because the user might be interested in tracing what is running on
+ * other CPUs. For instance, one might run osnoise in one HT CPU
+ * while observing what is running on the sibling HT CPU.
+ */
+static ssize_t
+osnoise_cpus_write(struct file *filp, const char __user *ubuf, size_t count,
+		   loff_t *ppos)
+{
+	cpumask_var_t osnoise_cpumask_new;
+	int running, err;
+	char buf[256];
+
+	if (count >= 256)
+		return -EINVAL;
+
+	if (copy_from_user(buf, ubuf, count))
+		return -EFAULT;
+
+	if (!zalloc_cpumask_var(&osnoise_cpumask_new, GFP_KERNEL))
+		return -ENOMEM;
+
+	err = cpulist_parse(buf, osnoise_cpumask_new);
+	if (err)
+		goto err_free;
+
+	/*
+	 * trace_types_lock is taken to avoid concurrency on start/stop.
+	 */
+	mutex_lock(&trace_types_lock);
+	running = osnoise_has_registered_instances();
+	if (running)
+		stop_per_cpu_kthreads();
+
+	mutex_lock(&interface_lock);
+	/*
+	 * osnoise_cpumask is read by CPU hotplug operations.
+	 */
+	cpus_read_lock();
+
+	cpumask_copy(&osnoise_cpumask, osnoise_cpumask_new);
+
+	cpus_read_unlock();
+	mutex_unlock(&interface_lock);
+
+	if (running)
+		start_per_cpu_kthreads();
+	mutex_unlock(&trace_types_lock);
+
+	free_cpumask_var(osnoise_cpumask_new);
+	return count;
+
+err_free:
+	free_cpumask_var(osnoise_cpumask_new);
+
+	return err;
+}
+
+/*
+ * osnoise/runtime_us: cannot be greater than the period.
+ */
+static struct trace_min_max_param osnoise_runtime = {
+	.lock	= &interface_lock,
+	.val	= &osnoise_data.sample_runtime,
+	.max	= &osnoise_data.sample_period,
+	.min	= NULL,
+};
+
+/*
+ * osnoise/period_us: cannot be smaller than the runtime.
+ */
+static struct trace_min_max_param osnoise_period = {
+	.lock	= &interface_lock,
+	.val	= &osnoise_data.sample_period,
+	.max	= NULL,
+	.min	= &osnoise_data.sample_runtime,
+};
+
+/*
+ * osnoise/stop_tracing_us: no limit.
+ */
+static struct trace_min_max_param osnoise_stop_tracing_in = {
+	.lock	= &interface_lock,
+	.val	= &osnoise_data.stop_tracing,
+	.max	= NULL,
+	.min	= NULL,
+};
+
+/*
+ * osnoise/stop_tracing_total_us: no limit.
+ */
+static struct trace_min_max_param osnoise_stop_tracing_total = {
+	.lock	= &interface_lock,
+	.val	= &osnoise_data.stop_tracing_total,
+	.max	= NULL,
+	.min	= NULL,
+};
+
+#ifdef CONFIG_TIMERLAT_TRACER
+/*
+ * osnoise/print_stack: print the stacktrace of the IRQ handler if the total
+ * latency is higher than val.
+ */
+static struct trace_min_max_param osnoise_print_stack = {
+	.lock	= &interface_lock,
+	.val	= &osnoise_data.print_stack,
+	.max	= NULL,
+	.min	= NULL,
+};
+
+/*
+ * osnoise/timerlat_period: min 100 us, max 1 s
+ */
+u64 timerlat_min_period = 100;
+u64 timerlat_max_period = 1000000;
+static struct trace_min_max_param timerlat_period = {
+	.lock	= &interface_lock,
+	.val	= &osnoise_data.timerlat_period,
+	.max	= &timerlat_max_period,
+	.min	= &timerlat_min_period,
+};
+#endif
+
+static const struct file_operations cpus_fops = {
+	.open		= tracing_open_generic,
+	.read		= osnoise_cpus_read,
+	.write		= osnoise_cpus_write,
+	.llseek		= generic_file_llseek,
+};
+
+#ifdef CONFIG_TIMERLAT_TRACER
+#ifdef CONFIG_STACKTRACE
+static int init_timerlat_stack_tracefs(struct dentry *top_dir)
+{
+	struct dentry *tmp;
+
+	tmp = tracefs_create_file("print_stack", TRACE_MODE_WRITE, top_dir,
+				  &osnoise_print_stack, &trace_min_max_fops);
+	if (!tmp)
+		return -ENOMEM;
+
+	return 0;
+}
+#else /* CONFIG_STACKTRACE */
+static int init_timerlat_stack_tracefs(struct dentry *top_dir)
+{
+	return 0;
+}
+#endif /* CONFIG_STACKTRACE */
+
+/*
+ * init_timerlat_tracefs - A function to initialize the timerlat interface files
+ */
+static int init_timerlat_tracefs(struct dentry *top_dir)
+{
+	struct dentry *tmp;
+
+	tmp = tracefs_create_file("timerlat_period_us", TRACE_MODE_WRITE, top_dir,
+				  &timerlat_period, &trace_min_max_fops);
+	if (!tmp)
+		return -ENOMEM;
+
+	return init_timerlat_stack_tracefs(top_dir);
+}
+#else /* CONFIG_TIMERLAT_TRACER */
+static int init_timerlat_tracefs(struct dentry *top_dir)
+{
+	return 0;
+}
+#endif /* CONFIG_TIMERLAT_TRACER */
+
+/*
+ * init_tracefs - A function to initialize the tracefs interface files
+ *
+ * This function creates entries in tracefs for "osnoise" and "timerlat".
+ * It creates these directories in the tracing directory, and within that
+ * directory the use can change and view the configs.
+ */
+static int init_tracefs(void)
+{
+	struct dentry *top_dir;
+	struct dentry *tmp;
+	int ret;
+
+	ret = tracing_init_dentry();
+	if (ret)
+		return -ENOMEM;
+
+	top_dir = tracefs_create_dir("osnoise", NULL);
+	if (!top_dir)
+		return 0;
+
+	tmp = tracefs_create_file("period_us", TRACE_MODE_WRITE, top_dir,
+				  &osnoise_period, &trace_min_max_fops);
+	if (!tmp)
+		goto err;
+
+	tmp = tracefs_create_file("runtime_us", TRACE_MODE_WRITE, top_dir,
+				  &osnoise_runtime, &trace_min_max_fops);
+	if (!tmp)
+		goto err;
+
+	tmp = tracefs_create_file("stop_tracing_us", TRACE_MODE_WRITE, top_dir,
+				  &osnoise_stop_tracing_in, &trace_min_max_fops);
+	if (!tmp)
+		goto err;
+
+	tmp = tracefs_create_file("stop_tracing_total_us", TRACE_MODE_WRITE, top_dir,
+				  &osnoise_stop_tracing_total, &trace_min_max_fops);
+	if (!tmp)
+		goto err;
+
+	tmp = trace_create_file("cpus", TRACE_MODE_WRITE, top_dir, NULL, &cpus_fops);
+	if (!tmp)
+		goto err;
+
+	ret = init_timerlat_tracefs(top_dir);
+	if (ret)
+		goto err;
+
+	return 0;
+
+err:
+	tracefs_remove(top_dir);
+	return -ENOMEM;
+}
+
+static int osnoise_hook_events(void)
+{
+	int retval;
+
+	/*
+	 * Trace is already hooked, we are re-enabling from
+	 * a stop_tracing_*.
+	 */
+	if (trace_osnoise_callback_enabled)
+		return 0;
+
+	retval = hook_irq_events();
+	if (retval)
+		return -EINVAL;
+
+	retval = hook_softirq_events();
+	if (retval)
+		goto out_unhook_irq;
+
+	retval = hook_thread_events();
+	/*
+	 * All fine!
+	 */
+	if (!retval)
+		return 0;
+
+	unhook_softirq_events();
+out_unhook_irq:
+	unhook_irq_events();
+	return -EINVAL;
+}
+
+static void osnoise_unhook_events(void)
+{
+	unhook_thread_events();
+	unhook_softirq_events();
+	unhook_irq_events();
+}
+
+/*
+ * osnoise_workload_start - start the workload and hook to events
+ */
+static int osnoise_workload_start(void)
+{
+	int retval;
+
+	/*
+	 * Instances need to be registered after calling workload
+	 * start. Hence, if there is already an instance, the
+	 * workload was already registered. Otherwise, this
+	 * code is on the way to register the first instance,
+	 * and the workload will start.
+	 */
+	if (osnoise_has_registered_instances())
+		return 0;
+
+	osn_var_reset_all();
+
+	retval = osnoise_hook_events();
+	if (retval)
+		return retval;
+
+	/*
+	 * Make sure that ftrace_nmi_enter/exit() see reset values
+	 * before enabling trace_osnoise_callback_enabled.
+	 */
+	barrier();
+	trace_osnoise_callback_enabled = true;
+
+	retval = start_per_cpu_kthreads();
+	if (retval) {
+		trace_osnoise_callback_enabled = false;
+		/*
+		 * Make sure that ftrace_nmi_enter/exit() see
+		 * trace_osnoise_callback_enabled as false before continuing.
+		 */
+		barrier();
+
+		osnoise_unhook_events();
+		return retval;
+	}
+
+	return 0;
+}
+
+/*
+ * osnoise_workload_stop - stop the workload and unhook the events
+ */
+static void osnoise_workload_stop(void)
+{
+	/*
+	 * Instances need to be unregistered before calling
+	 * stop. Hence, if there is a registered instance, more
+	 * than one instance is running, and the workload will not
+	 * yet stop. Otherwise, this code is on the way to disable
+	 * the last instance, and the workload can stop.
+	 */
+	if (osnoise_has_registered_instances())
+		return;
+
+	/*
+	 * If callbacks were already disabled in a previous stop
+	 * call, there is no need to disable then again.
+	 *
+	 * For instance, this happens when tracing is stopped via:
+	 * echo 0 > tracing_on
+	 * echo nop > current_tracer.
+	 */
+	if (!trace_osnoise_callback_enabled)
+		return;
+
+	trace_osnoise_callback_enabled = false;
+	/*
+	 * Make sure that ftrace_nmi_enter/exit() see
+	 * trace_osnoise_callback_enabled as false before continuing.
+	 */
+	barrier();
+
+	stop_per_cpu_kthreads();
+
+	osnoise_unhook_events();
+}
+
+static void osnoise_tracer_start(struct trace_array *tr)
+{
+	int retval;
+
+	/*
+	 * If the instance is already registered, there is no need to
+	 * register it again.
+	 */
+	if (osnoise_instance_registered(tr))
+		return;
+
+	retval = osnoise_workload_start();
+	if (retval)
+		pr_err(BANNER "Error starting osnoise tracer\n");
+
+	osnoise_register_instance(tr);
+}
+
+static void osnoise_tracer_stop(struct trace_array *tr)
+{
+	osnoise_unregister_instance(tr);
+	osnoise_workload_stop();
+}
+
+static int osnoise_tracer_init(struct trace_array *tr)
+{
+	/*
+	 * Only allow osnoise tracer if timerlat tracer is not running
+	 * already.
+	 */
+	if (timerlat_enabled())
+		return -EBUSY;
+
+	tr->max_latency = 0;
+
+	osnoise_tracer_start(tr);
+	return 0;
+}
+
+static void osnoise_tracer_reset(struct trace_array *tr)
+{
+	osnoise_tracer_stop(tr);
+}
+
+static struct tracer osnoise_tracer __read_mostly = {
+	.name		= "osnoise",
+	.init		= osnoise_tracer_init,
+	.reset		= osnoise_tracer_reset,
+	.start		= osnoise_tracer_start,
+	.stop		= osnoise_tracer_stop,
+	.print_header	= print_osnoise_headers,
+	.allow_instances = true,
+};
+
+#ifdef CONFIG_TIMERLAT_TRACER
+static void timerlat_tracer_start(struct trace_array *tr)
+{
+	int retval;
+
+	/*
+	 * If the instance is already registered, there is no need to
+	 * register it again.
+	 */
+	if (osnoise_instance_registered(tr))
+		return;
+
+	retval = osnoise_workload_start();
+	if (retval)
+		pr_err(BANNER "Error starting timerlat tracer\n");
+
+	osnoise_register_instance(tr);
+
+	return;
+}
+
+static void timerlat_tracer_stop(struct trace_array *tr)
+{
+	int cpu;
+
+	osnoise_unregister_instance(tr);
+
+	/*
+	 * Instruct the threads to stop only if this is the last instance.
+	 */
+	if (!osnoise_has_registered_instances()) {
+		for_each_online_cpu(cpu)
+			per_cpu(per_cpu_osnoise_var, cpu).sampling = 0;
+	}
+
+	osnoise_workload_stop();
+}
+
+static int timerlat_tracer_init(struct trace_array *tr)
+{
+	/*
+	 * Only allow timerlat tracer if osnoise tracer is not running already.
+	 */
+	if (osnoise_has_registered_instances() && !osnoise_data.timerlat_tracer)
+		return -EBUSY;
+
+	/*
+	 * If this is the first instance, set timerlat_tracer to block
+	 * osnoise tracer start.
+	 */
+	if (!osnoise_has_registered_instances())
+		osnoise_data.timerlat_tracer = 1;
+
+	tr->max_latency = 0;
+	timerlat_tracer_start(tr);
+
+	return 0;
+}
+
+static void timerlat_tracer_reset(struct trace_array *tr)
+{
+	timerlat_tracer_stop(tr);
+
+	/*
+	 * If this is the last instance, reset timerlat_tracer allowing
+	 * osnoise to be started.
+	 */
+	if (!osnoise_has_registered_instances())
+		osnoise_data.timerlat_tracer = 0;
+}
+
+static struct tracer timerlat_tracer __read_mostly = {
+	.name		= "timerlat",
+	.init		= timerlat_tracer_init,
+	.reset		= timerlat_tracer_reset,
+	.start		= timerlat_tracer_start,
+	.stop		= timerlat_tracer_stop,
+	.print_header	= print_timerlat_headers,
+	.allow_instances = true,
+};
+
+__init static int init_timerlat_tracer(void)
+{
+	return register_tracer(&timerlat_tracer);
+}
+#else /* CONFIG_TIMERLAT_TRACER */
+__init static int init_timerlat_tracer(void)
+{
+	return 0;
+}
+#endif /* CONFIG_TIMERLAT_TRACER */
+
+__init static int init_osnoise_tracer(void)
+{
+	int ret;
+
+	mutex_init(&interface_lock);
+
+	cpumask_copy(&osnoise_cpumask, cpu_all_mask);
+
+	ret = register_tracer(&osnoise_tracer);
+	if (ret) {
+		pr_err(BANNER "Error registering osnoise!\n");
+		return ret;
+	}
+
+	ret = init_timerlat_tracer();
+	if (ret) {
+		pr_err(BANNER "Error registering timerlat!\n");
+		return ret;
+	}
+
+	osnoise_init_hotplug_support();
+
+	INIT_LIST_HEAD_RCU(&osnoise_instances);
+
+	init_tracefs();
+
+	return 0;
+}
+late_initcall(init_osnoise_tracer);
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
new file mode 100644
index 000000000..bf1965b18
--- /dev/null
+++ b/kernel/trace/trace_output.c
@@ -0,0 +1,1585 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_output.c
+ *
+ * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ */
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/ftrace.h>
+#include <linux/kprobes.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/mm.h>
+
+#include "trace_output.h"
+
+/* must be a power of 2 */
+#define EVENT_HASHSIZE	128
+
+DECLARE_RWSEM(trace_event_sem);
+
+static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
+
+static int next_event_type = __TRACE_LAST_TYPE;
+
+enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
+{
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *entry = iter->ent;
+	struct bputs_entry *field;
+
+	trace_assign_type(field, entry);
+
+	trace_seq_puts(s, field->str);
+
+	return trace_handle_return(s);
+}
+
+enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
+{
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *entry = iter->ent;
+	struct bprint_entry *field;
+
+	trace_assign_type(field, entry);
+
+	trace_seq_bprintf(s, field->fmt, field->buf);
+
+	return trace_handle_return(s);
+}
+
+enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
+{
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *entry = iter->ent;
+	struct print_entry *field;
+
+	trace_assign_type(field, entry);
+
+	trace_seq_puts(s, field->buf);
+
+	return trace_handle_return(s);
+}
+
+const char *
+trace_print_flags_seq(struct trace_seq *p, const char *delim,
+		      unsigned long flags,
+		      const struct trace_print_flags *flag_array)
+{
+	unsigned long mask;
+	const char *str;
+	const char *ret = trace_seq_buffer_ptr(p);
+	int i, first = 1;
+
+	for (i = 0;  flag_array[i].name && flags; i++) {
+
+		mask = flag_array[i].mask;
+		if ((flags & mask) != mask)
+			continue;
+
+		str = flag_array[i].name;
+		flags &= ~mask;
+		if (!first && delim)
+			trace_seq_puts(p, delim);
+		else
+			first = 0;
+		trace_seq_puts(p, str);
+	}
+
+	/* check for left over flags */
+	if (flags) {
+		if (!first && delim)
+			trace_seq_puts(p, delim);
+		trace_seq_printf(p, "0x%lx", flags);
+	}
+
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+EXPORT_SYMBOL(trace_print_flags_seq);
+
+const char *
+trace_print_symbols_seq(struct trace_seq *p, unsigned long val,
+			const struct trace_print_flags *symbol_array)
+{
+	int i;
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	for (i = 0;  symbol_array[i].name; i++) {
+
+		if (val != symbol_array[i].mask)
+			continue;
+
+		trace_seq_puts(p, symbol_array[i].name);
+		break;
+	}
+
+	if (ret == (const char *)(trace_seq_buffer_ptr(p)))
+		trace_seq_printf(p, "0x%lx", val);
+
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+EXPORT_SYMBOL(trace_print_symbols_seq);
+
+#if BITS_PER_LONG == 32
+const char *
+trace_print_flags_seq_u64(struct trace_seq *p, const char *delim,
+		      unsigned long long flags,
+		      const struct trace_print_flags_u64 *flag_array)
+{
+	unsigned long long mask;
+	const char *str;
+	const char *ret = trace_seq_buffer_ptr(p);
+	int i, first = 1;
+
+	for (i = 0;  flag_array[i].name && flags; i++) {
+
+		mask = flag_array[i].mask;
+		if ((flags & mask) != mask)
+			continue;
+
+		str = flag_array[i].name;
+		flags &= ~mask;
+		if (!first && delim)
+			trace_seq_puts(p, delim);
+		else
+			first = 0;
+		trace_seq_puts(p, str);
+	}
+
+	/* check for left over flags */
+	if (flags) {
+		if (!first && delim)
+			trace_seq_puts(p, delim);
+		trace_seq_printf(p, "0x%llx", flags);
+	}
+
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+EXPORT_SYMBOL(trace_print_flags_seq_u64);
+
+const char *
+trace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val,
+			 const struct trace_print_flags_u64 *symbol_array)
+{
+	int i;
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	for (i = 0;  symbol_array[i].name; i++) {
+
+		if (val != symbol_array[i].mask)
+			continue;
+
+		trace_seq_puts(p, symbol_array[i].name);
+		break;
+	}
+
+	if (ret == (const char *)(trace_seq_buffer_ptr(p)))
+		trace_seq_printf(p, "0x%llx", val);
+
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+EXPORT_SYMBOL(trace_print_symbols_seq_u64);
+#endif
+
+const char *
+trace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
+			unsigned int bitmask_size)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_bitmask(p, bitmask_ptr, bitmask_size * 8);
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(trace_print_bitmask_seq);
+
+/**
+ * trace_print_hex_seq - print buffer as hex sequence
+ * @p: trace seq struct to write to
+ * @buf: The buffer to print
+ * @buf_len: Length of @buf in bytes
+ * @concatenate: Print @buf as single hex string or with spacing
+ *
+ * Prints the passed buffer as a hex sequence either as a whole,
+ * single hex string if @concatenate is true or with spacing after
+ * each byte in case @concatenate is false.
+ */
+const char *
+trace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len,
+		    bool concatenate)
+{
+	int i;
+	const char *ret = trace_seq_buffer_ptr(p);
+	const char *fmt = concatenate ? "%*phN" : "%*ph";
+
+	for (i = 0; i < buf_len; i += 16)
+		trace_seq_printf(p, fmt, min(buf_len - i, 16), &buf[i]);
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+EXPORT_SYMBOL(trace_print_hex_seq);
+
+const char *
+trace_print_array_seq(struct trace_seq *p, const void *buf, int count,
+		      size_t el_size)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+	const char *prefix = "";
+	void *ptr = (void *)buf;
+	size_t buf_len = count * el_size;
+
+	trace_seq_putc(p, '{');
+
+	while (ptr < buf + buf_len) {
+		switch (el_size) {
+		case 1:
+			trace_seq_printf(p, "%s0x%x", prefix,
+					 *(u8 *)ptr);
+			break;
+		case 2:
+			trace_seq_printf(p, "%s0x%x", prefix,
+					 *(u16 *)ptr);
+			break;
+		case 4:
+			trace_seq_printf(p, "%s0x%x", prefix,
+					 *(u32 *)ptr);
+			break;
+		case 8:
+			trace_seq_printf(p, "%s0x%llx", prefix,
+					 *(u64 *)ptr);
+			break;
+		default:
+			trace_seq_printf(p, "BAD SIZE:%zu 0x%x", el_size,
+					 *(u8 *)ptr);
+			el_size = 1;
+		}
+		prefix = ",";
+		ptr += el_size;
+	}
+
+	trace_seq_putc(p, '}');
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+EXPORT_SYMBOL(trace_print_array_seq);
+
+const char *
+trace_print_hex_dump_seq(struct trace_seq *p, const char *prefix_str,
+			 int prefix_type, int rowsize, int groupsize,
+			 const void *buf, size_t len, bool ascii)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_putc(p, '\n');
+	trace_seq_hex_dump(p, prefix_str, prefix_type,
+			   rowsize, groupsize, buf, len, ascii);
+	trace_seq_putc(p, 0);
+	return ret;
+}
+EXPORT_SYMBOL(trace_print_hex_dump_seq);
+
+int trace_raw_output_prep(struct trace_iterator *iter,
+			  struct trace_event *trace_event)
+{
+	struct trace_event_call *event;
+	struct trace_seq *s = &iter->seq;
+	struct trace_seq *p = &iter->tmp_seq;
+	struct trace_entry *entry;
+
+	event = container_of(trace_event, struct trace_event_call, event);
+	entry = iter->ent;
+
+	if (entry->type != event->event.type) {
+		WARN_ON_ONCE(1);
+		return TRACE_TYPE_UNHANDLED;
+	}
+
+	trace_seq_init(p);
+	trace_seq_printf(s, "%s: ", trace_event_name(event));
+
+	return trace_handle_return(s);
+}
+EXPORT_SYMBOL(trace_raw_output_prep);
+
+void trace_event_printf(struct trace_iterator *iter, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	trace_check_vprintf(iter, trace_event_format(iter, fmt), ap);
+	va_end(ap);
+}
+EXPORT_SYMBOL(trace_event_printf);
+
+static int trace_output_raw(struct trace_iterator *iter, char *name,
+			    char *fmt, va_list ap)
+{
+	struct trace_seq *s = &iter->seq;
+
+	trace_seq_printf(s, "%s: ", name);
+	trace_seq_vprintf(s, trace_event_format(iter, fmt), ap);
+
+	return trace_handle_return(s);
+}
+
+int trace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, fmt);
+	ret = trace_output_raw(iter, name, fmt, ap);
+	va_end(ap);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(trace_output_call);
+
+static inline const char *kretprobed(const char *name, unsigned long addr)
+{
+	if (is_kretprobe_trampoline(addr))
+		return "[unknown/kretprobe'd]";
+	return name;
+}
+
+void
+trace_seq_print_sym(struct trace_seq *s, unsigned long address, bool offset)
+{
+#ifdef CONFIG_KALLSYMS
+	char str[KSYM_SYMBOL_LEN];
+	const char *name;
+
+	if (offset)
+		sprint_symbol(str, address);
+	else
+		kallsyms_lookup(address, NULL, NULL, NULL, str);
+	name = kretprobed(str, address);
+
+	if (name && strlen(name)) {
+		trace_seq_puts(s, name);
+		return;
+	}
+#endif
+	trace_seq_printf(s, "0x%08lx", address);
+}
+
+#ifndef CONFIG_64BIT
+# define IP_FMT "%08lx"
+#else
+# define IP_FMT "%016lx"
+#endif
+
+static int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
+			     unsigned long ip, unsigned long sym_flags)
+{
+	struct file *file = NULL;
+	unsigned long vmstart = 0;
+	int ret = 1;
+
+	if (s->full)
+		return 0;
+
+	if (mm) {
+		const struct vm_area_struct *vma;
+
+		mmap_read_lock(mm);
+		vma = find_vma(mm, ip);
+		if (vma) {
+			file = vma->vm_file;
+			vmstart = vma->vm_start;
+		}
+		if (file) {
+			ret = trace_seq_path(s, &file->f_path);
+			if (ret)
+				trace_seq_printf(s, "[+0x%lx]",
+						 ip - vmstart);
+		}
+		mmap_read_unlock(mm);
+	}
+	if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
+		trace_seq_printf(s, " <" IP_FMT ">", ip);
+	return !trace_seq_has_overflowed(s);
+}
+
+int
+seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
+{
+	if (!ip) {
+		trace_seq_putc(s, '0');
+		goto out;
+	}
+
+	trace_seq_print_sym(s, ip, sym_flags & TRACE_ITER_SYM_OFFSET);
+
+	if (sym_flags & TRACE_ITER_SYM_ADDR)
+		trace_seq_printf(s, " <" IP_FMT ">", ip);
+
+ out:
+	return !trace_seq_has_overflowed(s);
+}
+
+/**
+ * trace_print_lat_fmt - print the irq, preempt and lockdep fields
+ * @s: trace seq struct to write to
+ * @entry: The trace entry field from the ring buffer
+ *
+ * Prints the generic fields of irqs off, in hard or softirq, preempt
+ * count.
+ */
+int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
+{
+	char hardsoft_irq;
+	char need_resched;
+	char irqs_off;
+	int hardirq;
+	int softirq;
+	int bh_off;
+	int nmi;
+
+	nmi = entry->flags & TRACE_FLAG_NMI;
+	hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
+	softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
+	bh_off = entry->flags & TRACE_FLAG_BH_OFF;
+
+	irqs_off =
+		(entry->flags & TRACE_FLAG_IRQS_OFF && bh_off) ? 'D' :
+		(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
+		bh_off ? 'b' :
+		(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
+		'.';
+
+	switch (entry->flags & (TRACE_FLAG_NEED_RESCHED |
+				TRACE_FLAG_PREEMPT_RESCHED)) {
+	case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_PREEMPT_RESCHED:
+		need_resched = 'N';
+		break;
+	case TRACE_FLAG_NEED_RESCHED:
+		need_resched = 'n';
+		break;
+	case TRACE_FLAG_PREEMPT_RESCHED:
+		need_resched = 'p';
+		break;
+	default:
+		need_resched = '.';
+		break;
+	}
+
+	hardsoft_irq =
+		(nmi && hardirq)     ? 'Z' :
+		nmi                  ? 'z' :
+		(hardirq && softirq) ? 'H' :
+		hardirq              ? 'h' :
+		softirq              ? 's' :
+		                       '.' ;
+
+	trace_seq_printf(s, "%c%c%c",
+			 irqs_off, need_resched, hardsoft_irq);
+
+	if (entry->preempt_count & 0xf)
+		trace_seq_printf(s, "%x", entry->preempt_count & 0xf);
+	else
+		trace_seq_putc(s, '.');
+
+	if (entry->preempt_count & 0xf0)
+		trace_seq_printf(s, "%x", entry->preempt_count >> 4);
+	else
+		trace_seq_putc(s, '.');
+
+	return !trace_seq_has_overflowed(s);
+}
+
+static int
+lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
+{
+	char comm[TASK_COMM_LEN];
+
+	trace_find_cmdline(entry->pid, comm);
+
+	trace_seq_printf(s, "%8.8s-%-7d %3d",
+			 comm, entry->pid, cpu);
+
+	return trace_print_lat_fmt(s, entry);
+}
+
+#undef MARK
+#define MARK(v, s) {.val = v, .sym = s}
+/* trace overhead mark */
+static const struct trace_mark {
+	unsigned long long	val; /* unit: nsec */
+	char			sym;
+} mark[] = {
+	MARK(1000000000ULL	, '$'), /* 1 sec */
+	MARK(100000000ULL	, '@'), /* 100 msec */
+	MARK(10000000ULL	, '*'), /* 10 msec */
+	MARK(1000000ULL		, '#'), /* 1000 usecs */
+	MARK(100000ULL		, '!'), /* 100 usecs */
+	MARK(10000ULL		, '+'), /* 10 usecs */
+};
+#undef MARK
+
+char trace_find_mark(unsigned long long d)
+{
+	int i;
+	int size = ARRAY_SIZE(mark);
+
+	for (i = 0; i < size; i++) {
+		if (d > mark[i].val)
+			break;
+	}
+
+	return (i == size) ? ' ' : mark[i].sym;
+}
+
+static int
+lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
+{
+	struct trace_array *tr = iter->tr;
+	unsigned long verbose = tr->trace_flags & TRACE_ITER_VERBOSE;
+	unsigned long in_ns = iter->iter_flags & TRACE_FILE_TIME_IN_NS;
+	unsigned long long abs_ts = iter->ts - iter->array_buffer->time_start;
+	unsigned long long rel_ts = next_ts - iter->ts;
+	struct trace_seq *s = &iter->seq;
+
+	if (in_ns) {
+		abs_ts = ns2usecs(abs_ts);
+		rel_ts = ns2usecs(rel_ts);
+	}
+
+	if (verbose && in_ns) {
+		unsigned long abs_usec = do_div(abs_ts, USEC_PER_MSEC);
+		unsigned long abs_msec = (unsigned long)abs_ts;
+		unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
+		unsigned long rel_msec = (unsigned long)rel_ts;
+
+		trace_seq_printf(
+			s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
+			ns2usecs(iter->ts),
+			abs_msec, abs_usec,
+			rel_msec, rel_usec);
+
+	} else if (verbose && !in_ns) {
+		trace_seq_printf(
+			s, "[%016llx] %lld (+%lld): ",
+			iter->ts, abs_ts, rel_ts);
+
+	} else if (!verbose && in_ns) {
+		trace_seq_printf(
+			s, " %4lldus%c: ",
+			abs_ts,
+			trace_find_mark(rel_ts * NSEC_PER_USEC));
+
+	} else { /* !verbose && !in_ns */
+		trace_seq_printf(s, " %4lld: ", abs_ts);
+	}
+
+	return !trace_seq_has_overflowed(s);
+}
+
+static void trace_print_time(struct trace_seq *s, struct trace_iterator *iter,
+			     unsigned long long ts)
+{
+	unsigned long secs, usec_rem;
+	unsigned long long t;
+
+	if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
+		t = ns2usecs(ts);
+		usec_rem = do_div(t, USEC_PER_SEC);
+		secs = (unsigned long)t;
+		trace_seq_printf(s, " %5lu.%06lu", secs, usec_rem);
+	} else
+		trace_seq_printf(s, " %12llu", ts);
+}
+
+int trace_print_context(struct trace_iterator *iter)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *entry = iter->ent;
+	char comm[TASK_COMM_LEN];
+
+	trace_find_cmdline(entry->pid, comm);
+
+	trace_seq_printf(s, "%16s-%-7d ", comm, entry->pid);
+
+	if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
+		unsigned int tgid = trace_find_tgid(entry->pid);
+
+		if (!tgid)
+			trace_seq_printf(s, "(-------) ");
+		else
+			trace_seq_printf(s, "(%7d) ", tgid);
+	}
+
+	trace_seq_printf(s, "[%03d] ", iter->cpu);
+
+	if (tr->trace_flags & TRACE_ITER_IRQ_INFO)
+		trace_print_lat_fmt(s, entry);
+
+	trace_print_time(s, iter, iter->ts);
+	trace_seq_puts(s, ": ");
+
+	return !trace_seq_has_overflowed(s);
+}
+
+int trace_print_lat_context(struct trace_iterator *iter)
+{
+	struct trace_entry *entry, *next_entry;
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	unsigned long verbose = (tr->trace_flags & TRACE_ITER_VERBOSE);
+	u64 next_ts;
+
+	next_entry = trace_find_next_entry(iter, NULL, &next_ts);
+	if (!next_entry)
+		next_ts = iter->ts;
+
+	/* trace_find_next_entry() may change iter->ent */
+	entry = iter->ent;
+
+	if (verbose) {
+		char comm[TASK_COMM_LEN];
+
+		trace_find_cmdline(entry->pid, comm);
+
+		trace_seq_printf(
+			s, "%16s %7d %3d %d %08x %08lx ",
+			comm, entry->pid, iter->cpu, entry->flags,
+			entry->preempt_count & 0xf, iter->idx);
+	} else {
+		lat_print_generic(s, entry, iter->cpu);
+	}
+
+	lat_print_timestamp(iter, next_ts);
+
+	return !trace_seq_has_overflowed(s);
+}
+
+/**
+ * ftrace_find_event - find a registered event
+ * @type: the type of event to look for
+ *
+ * Returns an event of type @type otherwise NULL
+ * Called with trace_event_read_lock() held.
+ */
+struct trace_event *ftrace_find_event(int type)
+{
+	struct trace_event *event;
+	unsigned key;
+
+	key = type & (EVENT_HASHSIZE - 1);
+
+	hlist_for_each_entry(event, &event_hash[key], node) {
+		if (event->type == type)
+			return event;
+	}
+
+	return NULL;
+}
+
+static LIST_HEAD(ftrace_event_list);
+
+static int trace_search_list(struct list_head **list)
+{
+	struct trace_event *e = NULL, *iter;
+	int next = __TRACE_LAST_TYPE;
+
+	if (list_empty(&ftrace_event_list)) {
+		*list = &ftrace_event_list;
+		return next;
+	}
+
+	/*
+	 * We used up all possible max events,
+	 * lets see if somebody freed one.
+	 */
+	list_for_each_entry(iter, &ftrace_event_list, list) {
+		if (iter->type != next) {
+			e = iter;
+			break;
+		}
+		next++;
+	}
+
+	/* Did we used up all 65 thousand events??? */
+	if (next > TRACE_EVENT_TYPE_MAX)
+		return 0;
+
+	if (e)
+		*list = &e->list;
+	else
+		*list = &ftrace_event_list;
+	return next;
+}
+
+void trace_event_read_lock(void)
+{
+	down_read(&trace_event_sem);
+}
+
+void trace_event_read_unlock(void)
+{
+	up_read(&trace_event_sem);
+}
+
+/**
+ * register_trace_event - register output for an event type
+ * @event: the event type to register
+ *
+ * Event types are stored in a hash and this hash is used to
+ * find a way to print an event. If the @event->type is set
+ * then it will use that type, otherwise it will assign a
+ * type to use.
+ *
+ * If you assign your own type, please make sure it is added
+ * to the trace_type enum in trace.h, to avoid collisions
+ * with the dynamic types.
+ *
+ * Returns the event type number or zero on error.
+ */
+int register_trace_event(struct trace_event *event)
+{
+	unsigned key;
+	int ret = 0;
+
+	down_write(&trace_event_sem);
+
+	if (WARN_ON(!event))
+		goto out;
+
+	if (WARN_ON(!event->funcs))
+		goto out;
+
+	INIT_LIST_HEAD(&event->list);
+
+	if (!event->type) {
+		struct list_head *list = NULL;
+
+		if (next_event_type > TRACE_EVENT_TYPE_MAX) {
+
+			event->type = trace_search_list(&list);
+			if (!event->type)
+				goto out;
+
+		} else {
+
+			event->type = next_event_type++;
+			list = &ftrace_event_list;
+		}
+
+		if (WARN_ON(ftrace_find_event(event->type)))
+			goto out;
+
+		list_add_tail(&event->list, list);
+
+	} else if (WARN(event->type > __TRACE_LAST_TYPE,
+			"Need to add type to trace.h")) {
+		goto out;
+	} else {
+		/* Is this event already used */
+		if (ftrace_find_event(event->type))
+			goto out;
+	}
+
+	if (event->funcs->trace == NULL)
+		event->funcs->trace = trace_nop_print;
+	if (event->funcs->raw == NULL)
+		event->funcs->raw = trace_nop_print;
+	if (event->funcs->hex == NULL)
+		event->funcs->hex = trace_nop_print;
+	if (event->funcs->binary == NULL)
+		event->funcs->binary = trace_nop_print;
+
+	key = event->type & (EVENT_HASHSIZE - 1);
+
+	hlist_add_head(&event->node, &event_hash[key]);
+
+	ret = event->type;
+ out:
+	up_write(&trace_event_sem);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_trace_event);
+
+/*
+ * Used by module code with the trace_event_sem held for write.
+ */
+int __unregister_trace_event(struct trace_event *event)
+{
+	hlist_del(&event->node);
+	list_del(&event->list);
+	return 0;
+}
+
+/**
+ * unregister_trace_event - remove a no longer used event
+ * @event: the event to remove
+ */
+int unregister_trace_event(struct trace_event *event)
+{
+	down_write(&trace_event_sem);
+	__unregister_trace_event(event);
+	up_write(&trace_event_sem);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(unregister_trace_event);
+
+/*
+ * Standard events
+ */
+
+enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
+				  struct trace_event *event)
+{
+	trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type);
+
+	return trace_handle_return(&iter->seq);
+}
+
+static void print_fn_trace(struct trace_seq *s, unsigned long ip,
+			   unsigned long parent_ip, int flags)
+{
+	seq_print_ip_sym(s, ip, flags);
+
+	if ((flags & TRACE_ITER_PRINT_PARENT) && parent_ip) {
+		trace_seq_puts(s, " <-");
+		seq_print_ip_sym(s, parent_ip, flags);
+	}
+}
+
+/* TRACE_FN */
+static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
+					struct trace_event *event)
+{
+	struct ftrace_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	print_fn_trace(s, field->ip, field->parent_ip, flags);
+	trace_seq_putc(s, '\n');
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
+				      struct trace_event *event)
+{
+	struct ftrace_entry *field;
+
+	trace_assign_type(field, iter->ent);
+
+	trace_seq_printf(&iter->seq, "%lx %lx\n",
+			 field->ip,
+			 field->parent_ip);
+
+	return trace_handle_return(&iter->seq);
+}
+
+static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
+				      struct trace_event *event)
+{
+	struct ftrace_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	SEQ_PUT_HEX_FIELD(s, field->ip);
+	SEQ_PUT_HEX_FIELD(s, field->parent_ip);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
+				      struct trace_event *event)
+{
+	struct ftrace_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	SEQ_PUT_FIELD(s, field->ip);
+	SEQ_PUT_FIELD(s, field->parent_ip);
+
+	return trace_handle_return(s);
+}
+
+static struct trace_event_functions trace_fn_funcs = {
+	.trace		= trace_fn_trace,
+	.raw		= trace_fn_raw,
+	.hex		= trace_fn_hex,
+	.binary		= trace_fn_bin,
+};
+
+static struct trace_event trace_fn_event = {
+	.type		= TRACE_FN,
+	.funcs		= &trace_fn_funcs,
+};
+
+/* TRACE_CTX an TRACE_WAKE */
+static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
+					     char *delim)
+{
+	struct ctx_switch_entry *field;
+	char comm[TASK_COMM_LEN];
+	int S, T;
+
+
+	trace_assign_type(field, iter->ent);
+
+	T = task_index_to_char(field->next_state);
+	S = task_index_to_char(field->prev_state);
+	trace_find_cmdline(field->next_pid, comm);
+	trace_seq_printf(&iter->seq,
+			 " %7d:%3d:%c %s [%03d] %7d:%3d:%c %s\n",
+			 field->prev_pid,
+			 field->prev_prio,
+			 S, delim,
+			 field->next_cpu,
+			 field->next_pid,
+			 field->next_prio,
+			 T, comm);
+
+	return trace_handle_return(&iter->seq);
+}
+
+static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
+					 struct trace_event *event)
+{
+	return trace_ctxwake_print(iter, "==>");
+}
+
+static enum print_line_t trace_wake_print(struct trace_iterator *iter,
+					  int flags, struct trace_event *event)
+{
+	return trace_ctxwake_print(iter, "  +");
+}
+
+static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
+{
+	struct ctx_switch_entry *field;
+	int T;
+
+	trace_assign_type(field, iter->ent);
+
+	if (!S)
+		S = task_index_to_char(field->prev_state);
+	T = task_index_to_char(field->next_state);
+	trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
+			 field->prev_pid,
+			 field->prev_prio,
+			 S,
+			 field->next_cpu,
+			 field->next_pid,
+			 field->next_prio,
+			 T);
+
+	return trace_handle_return(&iter->seq);
+}
+
+static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
+				       struct trace_event *event)
+{
+	return trace_ctxwake_raw(iter, 0);
+}
+
+static enum print_line_t trace_wake_raw(struct trace_iterator *iter, int flags,
+					struct trace_event *event)
+{
+	return trace_ctxwake_raw(iter, '+');
+}
+
+
+static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
+{
+	struct ctx_switch_entry *field;
+	struct trace_seq *s = &iter->seq;
+	int T;
+
+	trace_assign_type(field, iter->ent);
+
+	if (!S)
+		S = task_index_to_char(field->prev_state);
+	T = task_index_to_char(field->next_state);
+
+	SEQ_PUT_HEX_FIELD(s, field->prev_pid);
+	SEQ_PUT_HEX_FIELD(s, field->prev_prio);
+	SEQ_PUT_HEX_FIELD(s, S);
+	SEQ_PUT_HEX_FIELD(s, field->next_cpu);
+	SEQ_PUT_HEX_FIELD(s, field->next_pid);
+	SEQ_PUT_HEX_FIELD(s, field->next_prio);
+	SEQ_PUT_HEX_FIELD(s, T);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
+				       struct trace_event *event)
+{
+	return trace_ctxwake_hex(iter, 0);
+}
+
+static enum print_line_t trace_wake_hex(struct trace_iterator *iter, int flags,
+					struct trace_event *event)
+{
+	return trace_ctxwake_hex(iter, '+');
+}
+
+static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
+					   int flags, struct trace_event *event)
+{
+	struct ctx_switch_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	SEQ_PUT_FIELD(s, field->prev_pid);
+	SEQ_PUT_FIELD(s, field->prev_prio);
+	SEQ_PUT_FIELD(s, field->prev_state);
+	SEQ_PUT_FIELD(s, field->next_cpu);
+	SEQ_PUT_FIELD(s, field->next_pid);
+	SEQ_PUT_FIELD(s, field->next_prio);
+	SEQ_PUT_FIELD(s, field->next_state);
+
+	return trace_handle_return(s);
+}
+
+static struct trace_event_functions trace_ctx_funcs = {
+	.trace		= trace_ctx_print,
+	.raw		= trace_ctx_raw,
+	.hex		= trace_ctx_hex,
+	.binary		= trace_ctxwake_bin,
+};
+
+static struct trace_event trace_ctx_event = {
+	.type		= TRACE_CTX,
+	.funcs		= &trace_ctx_funcs,
+};
+
+static struct trace_event_functions trace_wake_funcs = {
+	.trace		= trace_wake_print,
+	.raw		= trace_wake_raw,
+	.hex		= trace_wake_hex,
+	.binary		= trace_ctxwake_bin,
+};
+
+static struct trace_event trace_wake_event = {
+	.type		= TRACE_WAKE,
+	.funcs		= &trace_wake_funcs,
+};
+
+/* TRACE_STACK */
+
+static enum print_line_t trace_stack_print(struct trace_iterator *iter,
+					   int flags, struct trace_event *event)
+{
+	struct stack_entry *field;
+	struct trace_seq *s = &iter->seq;
+	unsigned long *p;
+	unsigned long *end;
+
+	trace_assign_type(field, iter->ent);
+	end = (unsigned long *)((long)iter->ent + iter->ent_size);
+
+	trace_seq_puts(s, "<stack trace>\n");
+
+	for (p = field->caller; p && p < end && *p != ULONG_MAX; p++) {
+
+		if (trace_seq_has_overflowed(s))
+			break;
+
+		trace_seq_puts(s, " => ");
+		seq_print_ip_sym(s, *p, flags);
+		trace_seq_putc(s, '\n');
+	}
+
+	return trace_handle_return(s);
+}
+
+static struct trace_event_functions trace_stack_funcs = {
+	.trace		= trace_stack_print,
+};
+
+static struct trace_event trace_stack_event = {
+	.type		= TRACE_STACK,
+	.funcs		= &trace_stack_funcs,
+};
+
+/* TRACE_USER_STACK */
+static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
+						int flags, struct trace_event *event)
+{
+	struct trace_array *tr = iter->tr;
+	struct userstack_entry *field;
+	struct trace_seq *s = &iter->seq;
+	struct mm_struct *mm = NULL;
+	unsigned int i;
+
+	trace_assign_type(field, iter->ent);
+
+	trace_seq_puts(s, "<user stack trace>\n");
+
+	if (tr->trace_flags & TRACE_ITER_SYM_USEROBJ) {
+		struct task_struct *task;
+		/*
+		 * we do the lookup on the thread group leader,
+		 * since individual threads might have already quit!
+		 */
+		rcu_read_lock();
+		task = find_task_by_vpid(field->tgid);
+		if (task)
+			mm = get_task_mm(task);
+		rcu_read_unlock();
+	}
+
+	for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
+		unsigned long ip = field->caller[i];
+
+		if (!ip || trace_seq_has_overflowed(s))
+			break;
+
+		trace_seq_puts(s, " => ");
+		seq_print_user_ip(s, mm, ip, flags);
+		trace_seq_putc(s, '\n');
+	}
+
+	if (mm)
+		mmput(mm);
+
+	return trace_handle_return(s);
+}
+
+static struct trace_event_functions trace_user_stack_funcs = {
+	.trace		= trace_user_stack_print,
+};
+
+static struct trace_event trace_user_stack_event = {
+	.type		= TRACE_USER_STACK,
+	.funcs		= &trace_user_stack_funcs,
+};
+
+/* TRACE_HWLAT */
+static enum print_line_t
+trace_hwlat_print(struct trace_iterator *iter, int flags,
+		  struct trace_event *event)
+{
+	struct trace_entry *entry = iter->ent;
+	struct trace_seq *s = &iter->seq;
+	struct hwlat_entry *field;
+
+	trace_assign_type(field, entry);
+
+	trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%lld.%09ld count:%d",
+			 field->seqnum,
+			 field->duration,
+			 field->outer_duration,
+			 (long long)field->timestamp.tv_sec,
+			 field->timestamp.tv_nsec, field->count);
+
+	if (field->nmi_count) {
+		/*
+		 * The generic sched_clock() is not NMI safe, thus
+		 * we only record the count and not the time.
+		 */
+		if (!IS_ENABLED(CONFIG_GENERIC_SCHED_CLOCK))
+			trace_seq_printf(s, " nmi-total:%llu",
+					 field->nmi_total_ts);
+		trace_seq_printf(s, " nmi-count:%u",
+				 field->nmi_count);
+	}
+
+	trace_seq_putc(s, '\n');
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t
+trace_hwlat_raw(struct trace_iterator *iter, int flags,
+		struct trace_event *event)
+{
+	struct hwlat_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	trace_seq_printf(s, "%llu %lld %lld %09ld %u\n",
+			 field->duration,
+			 field->outer_duration,
+			 (long long)field->timestamp.tv_sec,
+			 field->timestamp.tv_nsec,
+			 field->seqnum);
+
+	return trace_handle_return(s);
+}
+
+static struct trace_event_functions trace_hwlat_funcs = {
+	.trace		= trace_hwlat_print,
+	.raw		= trace_hwlat_raw,
+};
+
+static struct trace_event trace_hwlat_event = {
+	.type		= TRACE_HWLAT,
+	.funcs		= &trace_hwlat_funcs,
+};
+
+/* TRACE_OSNOISE */
+static enum print_line_t
+trace_osnoise_print(struct trace_iterator *iter, int flags,
+		    struct trace_event *event)
+{
+	struct trace_entry *entry = iter->ent;
+	struct trace_seq *s = &iter->seq;
+	struct osnoise_entry *field;
+	u64 ratio, ratio_dec;
+	u64 net_runtime;
+
+	trace_assign_type(field, entry);
+
+	/*
+	 * compute the available % of cpu time.
+	 */
+	net_runtime = field->runtime - field->noise;
+	ratio = net_runtime * 10000000;
+	do_div(ratio, field->runtime);
+	ratio_dec = do_div(ratio, 100000);
+
+	trace_seq_printf(s, "%llu %10llu %3llu.%05llu %7llu",
+			 field->runtime,
+			 field->noise,
+			 ratio, ratio_dec,
+			 field->max_sample);
+
+	trace_seq_printf(s, " %6u", field->hw_count);
+	trace_seq_printf(s, " %6u", field->nmi_count);
+	trace_seq_printf(s, " %6u", field->irq_count);
+	trace_seq_printf(s, " %6u", field->softirq_count);
+	trace_seq_printf(s, " %6u", field->thread_count);
+
+	trace_seq_putc(s, '\n');
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t
+trace_osnoise_raw(struct trace_iterator *iter, int flags,
+		  struct trace_event *event)
+{
+	struct osnoise_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	trace_seq_printf(s, "%lld %llu %llu %u %u %u %u %u\n",
+			 field->runtime,
+			 field->noise,
+			 field->max_sample,
+			 field->hw_count,
+			 field->nmi_count,
+			 field->irq_count,
+			 field->softirq_count,
+			 field->thread_count);
+
+	return trace_handle_return(s);
+}
+
+static struct trace_event_functions trace_osnoise_funcs = {
+	.trace		= trace_osnoise_print,
+	.raw		= trace_osnoise_raw,
+};
+
+static struct trace_event trace_osnoise_event = {
+	.type		= TRACE_OSNOISE,
+	.funcs		= &trace_osnoise_funcs,
+};
+
+/* TRACE_TIMERLAT */
+static enum print_line_t
+trace_timerlat_print(struct trace_iterator *iter, int flags,
+		     struct trace_event *event)
+{
+	struct trace_entry *entry = iter->ent;
+	struct trace_seq *s = &iter->seq;
+	struct timerlat_entry *field;
+
+	trace_assign_type(field, entry);
+
+	trace_seq_printf(s, "#%-5u context %6s timer_latency %9llu ns\n",
+			 field->seqnum,
+			 field->context ? "thread" : "irq",
+			 field->timer_latency);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t
+trace_timerlat_raw(struct trace_iterator *iter, int flags,
+		   struct trace_event *event)
+{
+	struct timerlat_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	trace_seq_printf(s, "%u %d %llu\n",
+			 field->seqnum,
+			 field->context,
+			 field->timer_latency);
+
+	return trace_handle_return(s);
+}
+
+static struct trace_event_functions trace_timerlat_funcs = {
+	.trace		= trace_timerlat_print,
+	.raw		= trace_timerlat_raw,
+};
+
+static struct trace_event trace_timerlat_event = {
+	.type		= TRACE_TIMERLAT,
+	.funcs		= &trace_timerlat_funcs,
+};
+
+/* TRACE_BPUTS */
+static enum print_line_t
+trace_bputs_print(struct trace_iterator *iter, int flags,
+		   struct trace_event *event)
+{
+	struct trace_entry *entry = iter->ent;
+	struct trace_seq *s = &iter->seq;
+	struct bputs_entry *field;
+
+	trace_assign_type(field, entry);
+
+	seq_print_ip_sym(s, field->ip, flags);
+	trace_seq_puts(s, ": ");
+	trace_seq_puts(s, field->str);
+
+	return trace_handle_return(s);
+}
+
+
+static enum print_line_t
+trace_bputs_raw(struct trace_iterator *iter, int flags,
+		struct trace_event *event)
+{
+	struct bputs_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	trace_seq_printf(s, ": %lx : ", field->ip);
+	trace_seq_puts(s, field->str);
+
+	return trace_handle_return(s);
+}
+
+static struct trace_event_functions trace_bputs_funcs = {
+	.trace		= trace_bputs_print,
+	.raw		= trace_bputs_raw,
+};
+
+static struct trace_event trace_bputs_event = {
+	.type		= TRACE_BPUTS,
+	.funcs		= &trace_bputs_funcs,
+};
+
+/* TRACE_BPRINT */
+static enum print_line_t
+trace_bprint_print(struct trace_iterator *iter, int flags,
+		   struct trace_event *event)
+{
+	struct trace_entry *entry = iter->ent;
+	struct trace_seq *s = &iter->seq;
+	struct bprint_entry *field;
+
+	trace_assign_type(field, entry);
+
+	seq_print_ip_sym(s, field->ip, flags);
+	trace_seq_puts(s, ": ");
+	trace_seq_bprintf(s, field->fmt, field->buf);
+
+	return trace_handle_return(s);
+}
+
+
+static enum print_line_t
+trace_bprint_raw(struct trace_iterator *iter, int flags,
+		 struct trace_event *event)
+{
+	struct bprint_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	trace_seq_printf(s, ": %lx : ", field->ip);
+	trace_seq_bprintf(s, field->fmt, field->buf);
+
+	return trace_handle_return(s);
+}
+
+static struct trace_event_functions trace_bprint_funcs = {
+	.trace		= trace_bprint_print,
+	.raw		= trace_bprint_raw,
+};
+
+static struct trace_event trace_bprint_event = {
+	.type		= TRACE_BPRINT,
+	.funcs		= &trace_bprint_funcs,
+};
+
+/* TRACE_PRINT */
+static enum print_line_t trace_print_print(struct trace_iterator *iter,
+					   int flags, struct trace_event *event)
+{
+	struct print_entry *field;
+	struct trace_seq *s = &iter->seq;
+	int max = iter->ent_size - offsetof(struct print_entry, buf);
+
+	trace_assign_type(field, iter->ent);
+
+	seq_print_ip_sym(s, field->ip, flags);
+	trace_seq_printf(s, ": %.*s", max, field->buf);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
+					 struct trace_event *event)
+{
+	struct print_entry *field;
+	int max = iter->ent_size - offsetof(struct print_entry, buf);
+
+	trace_assign_type(field, iter->ent);
+
+	trace_seq_printf(&iter->seq, "# %lx %.*s", field->ip, max, field->buf);
+
+	return trace_handle_return(&iter->seq);
+}
+
+static struct trace_event_functions trace_print_funcs = {
+	.trace		= trace_print_print,
+	.raw		= trace_print_raw,
+};
+
+static struct trace_event trace_print_event = {
+	.type	 	= TRACE_PRINT,
+	.funcs		= &trace_print_funcs,
+};
+
+static enum print_line_t trace_raw_data(struct trace_iterator *iter, int flags,
+					 struct trace_event *event)
+{
+	struct raw_data_entry *field;
+	int i;
+
+	trace_assign_type(field, iter->ent);
+
+	trace_seq_printf(&iter->seq, "# %x buf:", field->id);
+
+	for (i = 0; i < iter->ent_size - offsetof(struct raw_data_entry, buf); i++)
+		trace_seq_printf(&iter->seq, " %02x",
+				 (unsigned char)field->buf[i]);
+
+	trace_seq_putc(&iter->seq, '\n');
+
+	return trace_handle_return(&iter->seq);
+}
+
+static struct trace_event_functions trace_raw_data_funcs = {
+	.trace		= trace_raw_data,
+	.raw		= trace_raw_data,
+};
+
+static struct trace_event trace_raw_data_event = {
+	.type	 	= TRACE_RAW_DATA,
+	.funcs		= &trace_raw_data_funcs,
+};
+
+static enum print_line_t
+trace_func_repeats_raw(struct trace_iterator *iter, int flags,
+			 struct trace_event *event)
+{
+	struct func_repeats_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	trace_seq_printf(s, "%lu %lu %u %llu\n",
+			 field->ip,
+			 field->parent_ip,
+			 field->count,
+			 FUNC_REPEATS_GET_DELTA_TS(field));
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t
+trace_func_repeats_print(struct trace_iterator *iter, int flags,
+			 struct trace_event *event)
+{
+	struct func_repeats_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	print_fn_trace(s, field->ip, field->parent_ip, flags);
+	trace_seq_printf(s, " (repeats: %u, last_ts:", field->count);
+	trace_print_time(s, iter,
+			 iter->ts - FUNC_REPEATS_GET_DELTA_TS(field));
+	trace_seq_puts(s, ")\n");
+
+	return trace_handle_return(s);
+}
+
+static struct trace_event_functions trace_func_repeats_funcs = {
+	.trace		= trace_func_repeats_print,
+	.raw		= trace_func_repeats_raw,
+};
+
+static struct trace_event trace_func_repeats_event = {
+	.type	 	= TRACE_FUNC_REPEATS,
+	.funcs		= &trace_func_repeats_funcs,
+};
+
+static struct trace_event *events[] __initdata = {
+	&trace_fn_event,
+	&trace_ctx_event,
+	&trace_wake_event,
+	&trace_stack_event,
+	&trace_user_stack_event,
+	&trace_bputs_event,
+	&trace_bprint_event,
+	&trace_print_event,
+	&trace_hwlat_event,
+	&trace_osnoise_event,
+	&trace_timerlat_event,
+	&trace_raw_data_event,
+	&trace_func_repeats_event,
+	NULL
+};
+
+__init int init_events(void)
+{
+	struct trace_event *event;
+	int i, ret;
+
+	for (i = 0; events[i]; i++) {
+		event = events[i];
+		ret = register_trace_event(event);
+		WARN_ONCE(!ret, "event %d failed to register", event->type);
+	}
+
+	return 0;
+}
diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h
new file mode 100644
index 000000000..4c954636c
--- /dev/null
+++ b/kernel/trace/trace_output.h
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef __TRACE_EVENTS_H
+#define __TRACE_EVENTS_H
+
+#include <linux/trace_seq.h>
+#include "trace.h"
+
+extern enum print_line_t
+trace_print_bputs_msg_only(struct trace_iterator *iter);
+extern enum print_line_t
+trace_print_bprintk_msg_only(struct trace_iterator *iter);
+extern enum print_line_t
+trace_print_printk_msg_only(struct trace_iterator *iter);
+
+extern int
+seq_print_ip_sym(struct trace_seq *s, unsigned long ip,
+		unsigned long sym_flags);
+
+extern void trace_seq_print_sym(struct trace_seq *s, unsigned long address, bool offset);
+extern int trace_print_context(struct trace_iterator *iter);
+extern int trace_print_lat_context(struct trace_iterator *iter);
+
+extern void trace_event_read_lock(void);
+extern void trace_event_read_unlock(void);
+extern struct trace_event *ftrace_find_event(int type);
+
+extern enum print_line_t trace_nop_print(struct trace_iterator *iter,
+					 int flags, struct trace_event *event);
+extern int
+trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry);
+
+/* used by module unregistering */
+extern int __unregister_trace_event(struct trace_event *event);
+extern struct rw_semaphore trace_event_sem;
+
+#define SEQ_PUT_FIELD(s, x)				\
+	trace_seq_putmem(s, &(x), sizeof(x))
+
+#define SEQ_PUT_HEX_FIELD(s, x)				\
+	trace_seq_putmem_hex(s, &(x), sizeof(x))
+
+#endif
+
diff --git a/kernel/trace/trace_preemptirq.c b/kernel/trace/trace_preemptirq.c
new file mode 100644
index 000000000..1e130da1b
--- /dev/null
+++ b/kernel/trace/trace_preemptirq.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * preemptoff and irqoff tracepoints
+ *
+ * Copyright (C) Joel Fernandes (Google) <joel@joelfernandes.org>
+ */
+
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+#include <linux/kprobes.h>
+#include "trace.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/preemptirq.h>
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+/* Per-cpu variable to prevent redundant calls when IRQs already off */
+static DEFINE_PER_CPU(int, tracing_irq_cpu);
+
+/*
+ * Like trace_hardirqs_on() but without the lockdep invocation. This is
+ * used in the low level entry code where the ordering vs. RCU is important
+ * and lockdep uses a staged approach which splits the lockdep hardirq
+ * tracking into a RCU on and a RCU off section.
+ */
+void trace_hardirqs_on_prepare(void)
+{
+	if (this_cpu_read(tracing_irq_cpu)) {
+		if (!in_nmi())
+			trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1);
+		tracer_hardirqs_on(CALLER_ADDR0, CALLER_ADDR1);
+		this_cpu_write(tracing_irq_cpu, 0);
+	}
+}
+EXPORT_SYMBOL(trace_hardirqs_on_prepare);
+NOKPROBE_SYMBOL(trace_hardirqs_on_prepare);
+
+void trace_hardirqs_on(void)
+{
+	if (this_cpu_read(tracing_irq_cpu)) {
+		if (!in_nmi())
+			trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+		tracer_hardirqs_on(CALLER_ADDR0, CALLER_ADDR1);
+		this_cpu_write(tracing_irq_cpu, 0);
+	}
+
+	lockdep_hardirqs_on_prepare();
+	lockdep_hardirqs_on(CALLER_ADDR0);
+}
+EXPORT_SYMBOL(trace_hardirqs_on);
+NOKPROBE_SYMBOL(trace_hardirqs_on);
+
+/*
+ * Like trace_hardirqs_off() but without the lockdep invocation. This is
+ * used in the low level entry code where the ordering vs. RCU is important
+ * and lockdep uses a staged approach which splits the lockdep hardirq
+ * tracking into a RCU on and a RCU off section.
+ */
+void trace_hardirqs_off_finish(void)
+{
+	if (!this_cpu_read(tracing_irq_cpu)) {
+		this_cpu_write(tracing_irq_cpu, 1);
+		tracer_hardirqs_off(CALLER_ADDR0, CALLER_ADDR1);
+		if (!in_nmi())
+			trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1);
+	}
+
+}
+EXPORT_SYMBOL(trace_hardirqs_off_finish);
+NOKPROBE_SYMBOL(trace_hardirqs_off_finish);
+
+void trace_hardirqs_off(void)
+{
+	lockdep_hardirqs_off(CALLER_ADDR0);
+
+	if (!this_cpu_read(tracing_irq_cpu)) {
+		this_cpu_write(tracing_irq_cpu, 1);
+		tracer_hardirqs_off(CALLER_ADDR0, CALLER_ADDR1);
+		if (!in_nmi())
+			trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+	}
+}
+EXPORT_SYMBOL(trace_hardirqs_off);
+NOKPROBE_SYMBOL(trace_hardirqs_off);
+
+__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
+{
+	if (this_cpu_read(tracing_irq_cpu)) {
+		if (!in_nmi())
+			trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
+		tracer_hardirqs_on(CALLER_ADDR0, caller_addr);
+		this_cpu_write(tracing_irq_cpu, 0);
+	}
+
+	lockdep_hardirqs_on_prepare();
+	lockdep_hardirqs_on(caller_addr);
+}
+EXPORT_SYMBOL(trace_hardirqs_on_caller);
+NOKPROBE_SYMBOL(trace_hardirqs_on_caller);
+
+__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
+{
+	lockdep_hardirqs_off(caller_addr);
+
+	if (!this_cpu_read(tracing_irq_cpu)) {
+		this_cpu_write(tracing_irq_cpu, 1);
+		tracer_hardirqs_off(CALLER_ADDR0, caller_addr);
+		if (!in_nmi())
+			trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
+	}
+}
+EXPORT_SYMBOL(trace_hardirqs_off_caller);
+NOKPROBE_SYMBOL(trace_hardirqs_off_caller);
+#endif /* CONFIG_TRACE_IRQFLAGS */
+
+#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
+
+void trace_preempt_on(unsigned long a0, unsigned long a1)
+{
+	if (!in_nmi())
+		trace_preempt_enable_rcuidle(a0, a1);
+	tracer_preempt_on(a0, a1);
+}
+
+void trace_preempt_off(unsigned long a0, unsigned long a1)
+{
+	if (!in_nmi())
+		trace_preempt_disable_rcuidle(a0, a1);
+	tracer_preempt_off(a0, a1);
+}
+#endif
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
new file mode 100644
index 000000000..29f6e9543
--- /dev/null
+++ b/kernel/trace/trace_printk.c
@@ -0,0 +1,400 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace binary printk
+ *
+ * Copyright (C) 2008 Lai Jiangshan <laijs@cn.fujitsu.com>
+ *
+ */
+#include <linux/seq_file.h>
+#include <linux/security.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/ftrace.h>
+#include <linux/string.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/ctype.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+#include "trace.h"
+
+#ifdef CONFIG_MODULES
+
+/*
+ * modules trace_printk()'s formats are autosaved in struct trace_bprintk_fmt
+ * which are queued on trace_bprintk_fmt_list.
+ */
+static LIST_HEAD(trace_bprintk_fmt_list);
+
+/* serialize accesses to trace_bprintk_fmt_list */
+static DEFINE_MUTEX(btrace_mutex);
+
+struct trace_bprintk_fmt {
+	struct list_head list;
+	const char *fmt;
+};
+
+static inline struct trace_bprintk_fmt *lookup_format(const char *fmt)
+{
+	struct trace_bprintk_fmt *pos;
+
+	if (!fmt)
+		return ERR_PTR(-EINVAL);
+
+	list_for_each_entry(pos, &trace_bprintk_fmt_list, list) {
+		if (!strcmp(pos->fmt, fmt))
+			return pos;
+	}
+	return NULL;
+}
+
+static
+void hold_module_trace_bprintk_format(const char **start, const char **end)
+{
+	const char **iter;
+	char *fmt;
+
+	/* allocate the trace_printk per cpu buffers */
+	if (start != end)
+		trace_printk_init_buffers();
+
+	mutex_lock(&btrace_mutex);
+	for (iter = start; iter < end; iter++) {
+		struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter);
+		if (tb_fmt) {
+			if (!IS_ERR(tb_fmt))
+				*iter = tb_fmt->fmt;
+			continue;
+		}
+
+		fmt = NULL;
+		tb_fmt = kmalloc(sizeof(*tb_fmt), GFP_KERNEL);
+		if (tb_fmt) {
+			fmt = kmalloc(strlen(*iter) + 1, GFP_KERNEL);
+			if (fmt) {
+				list_add_tail(&tb_fmt->list, &trace_bprintk_fmt_list);
+				strcpy(fmt, *iter);
+				tb_fmt->fmt = fmt;
+			} else
+				kfree(tb_fmt);
+		}
+		*iter = fmt;
+
+	}
+	mutex_unlock(&btrace_mutex);
+}
+
+static int module_trace_bprintk_format_notify(struct notifier_block *self,
+		unsigned long val, void *data)
+{
+	struct module *mod = data;
+	if (mod->num_trace_bprintk_fmt) {
+		const char **start = mod->trace_bprintk_fmt_start;
+		const char **end = start + mod->num_trace_bprintk_fmt;
+
+		if (val == MODULE_STATE_COMING)
+			hold_module_trace_bprintk_format(start, end);
+	}
+	return NOTIFY_OK;
+}
+
+/*
+ * The debugfs/tracing/printk_formats file maps the addresses with
+ * the ASCII formats that are used in the bprintk events in the
+ * buffer. For userspace tools to be able to decode the events from
+ * the buffer, they need to be able to map the address with the format.
+ *
+ * The addresses of the bprintk formats are in their own section
+ * __trace_printk_fmt. But for modules we copy them into a link list.
+ * The code to print the formats and their addresses passes around the
+ * address of the fmt string. If the fmt address passed into the seq
+ * functions is within the kernel core __trace_printk_fmt section, then
+ * it simply uses the next pointer in the list.
+ *
+ * When the fmt pointer is outside the kernel core __trace_printk_fmt
+ * section, then we need to read the link list pointers. The trick is
+ * we pass the address of the string to the seq function just like
+ * we do for the kernel core formats. To get back the structure that
+ * holds the format, we simply use container_of() and then go to the
+ * next format in the list.
+ */
+static const char **
+find_next_mod_format(int start_index, void *v, const char **fmt, loff_t *pos)
+{
+	struct trace_bprintk_fmt *mod_fmt;
+
+	if (list_empty(&trace_bprintk_fmt_list))
+		return NULL;
+
+	/*
+	 * v will point to the address of the fmt record from t_next
+	 * v will be NULL from t_start.
+	 * If this is the first pointer or called from start
+	 * then we need to walk the list.
+	 */
+	if (!v || start_index == *pos) {
+		struct trace_bprintk_fmt *p;
+
+		/* search the module list */
+		list_for_each_entry(p, &trace_bprintk_fmt_list, list) {
+			if (start_index == *pos)
+				return &p->fmt;
+			start_index++;
+		}
+		/* pos > index */
+		return NULL;
+	}
+
+	/*
+	 * v points to the address of the fmt field in the mod list
+	 * structure that holds the module print format.
+	 */
+	mod_fmt = container_of(v, typeof(*mod_fmt), fmt);
+	if (mod_fmt->list.next == &trace_bprintk_fmt_list)
+		return NULL;
+
+	mod_fmt = container_of(mod_fmt->list.next, typeof(*mod_fmt), list);
+
+	return &mod_fmt->fmt;
+}
+
+static void format_mod_start(void)
+{
+	mutex_lock(&btrace_mutex);
+}
+
+static void format_mod_stop(void)
+{
+	mutex_unlock(&btrace_mutex);
+}
+
+#else /* !CONFIG_MODULES */
+__init static int
+module_trace_bprintk_format_notify(struct notifier_block *self,
+		unsigned long val, void *data)
+{
+	return NOTIFY_OK;
+}
+static inline const char **
+find_next_mod_format(int start_index, void *v, const char **fmt, loff_t *pos)
+{
+	return NULL;
+}
+static inline void format_mod_start(void) { }
+static inline void format_mod_stop(void) { }
+#endif /* CONFIG_MODULES */
+
+static bool __read_mostly trace_printk_enabled = true;
+
+void trace_printk_control(bool enabled)
+{
+	trace_printk_enabled = enabled;
+}
+
+__initdata_or_module static
+struct notifier_block module_trace_bprintk_format_nb = {
+	.notifier_call = module_trace_bprintk_format_notify,
+};
+
+int __trace_bprintk(unsigned long ip, const char *fmt, ...)
+{
+	int ret;
+	va_list ap;
+
+	if (unlikely(!fmt))
+		return 0;
+
+	if (!trace_printk_enabled)
+		return 0;
+
+	va_start(ap, fmt);
+	ret = trace_vbprintk(ip, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__trace_bprintk);
+
+int __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap)
+{
+	if (unlikely(!fmt))
+		return 0;
+
+	if (!trace_printk_enabled)
+		return 0;
+
+	return trace_vbprintk(ip, fmt, ap);
+}
+EXPORT_SYMBOL_GPL(__ftrace_vbprintk);
+
+int __trace_printk(unsigned long ip, const char *fmt, ...)
+{
+	int ret;
+	va_list ap;
+
+	if (!trace_printk_enabled)
+		return 0;
+
+	va_start(ap, fmt);
+	ret = trace_vprintk(ip, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__trace_printk);
+
+int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
+{
+	if (!trace_printk_enabled)
+		return 0;
+
+	return trace_vprintk(ip, fmt, ap);
+}
+EXPORT_SYMBOL_GPL(__ftrace_vprintk);
+
+bool trace_is_tracepoint_string(const char *str)
+{
+	const char **ptr = __start___tracepoint_str;
+
+	for (ptr = __start___tracepoint_str; ptr < __stop___tracepoint_str; ptr++) {
+		if (str == *ptr)
+			return true;
+	}
+	return false;
+}
+
+static const char **find_next(void *v, loff_t *pos)
+{
+	const char **fmt = v;
+	int start_index;
+	int last_index;
+
+	start_index = __stop___trace_bprintk_fmt - __start___trace_bprintk_fmt;
+
+	if (*pos < start_index)
+		return __start___trace_bprintk_fmt + *pos;
+
+	/*
+	 * The __tracepoint_str section is treated the same as the
+	 * __trace_printk_fmt section. The difference is that the
+	 * __trace_printk_fmt section should only be used by trace_printk()
+	 * in a debugging environment, as if anything exists in that section
+	 * the trace_prink() helper buffers are allocated, which would just
+	 * waste space in a production environment.
+	 *
+	 * The __tracepoint_str sections on the other hand are used by
+	 * tracepoints which need to map pointers to their strings to
+	 * the ASCII text for userspace.
+	 */
+	last_index = start_index;
+	start_index = __stop___tracepoint_str - __start___tracepoint_str;
+
+	if (*pos < last_index + start_index)
+		return __start___tracepoint_str + (*pos - last_index);
+
+	start_index += last_index;
+	return find_next_mod_format(start_index, v, fmt, pos);
+}
+
+static void *
+t_start(struct seq_file *m, loff_t *pos)
+{
+	format_mod_start();
+	return find_next(NULL, pos);
+}
+
+static void *t_next(struct seq_file *m, void * v, loff_t *pos)
+{
+	(*pos)++;
+	return find_next(v, pos);
+}
+
+static int t_show(struct seq_file *m, void *v)
+{
+	const char **fmt = v;
+	const char *str = *fmt;
+	int i;
+
+	if (!*fmt)
+		return 0;
+
+	seq_printf(m, "0x%lx : \"", *(unsigned long *)fmt);
+
+	/*
+	 * Tabs and new lines need to be converted.
+	 */
+	for (i = 0; str[i]; i++) {
+		switch (str[i]) {
+		case '\n':
+			seq_puts(m, "\\n");
+			break;
+		case '\t':
+			seq_puts(m, "\\t");
+			break;
+		case '\\':
+			seq_putc(m, '\\');
+			break;
+		case '"':
+			seq_puts(m, "\\\"");
+			break;
+		default:
+			seq_putc(m, str[i]);
+		}
+	}
+	seq_puts(m, "\"\n");
+
+	return 0;
+}
+
+static void t_stop(struct seq_file *m, void *p)
+{
+	format_mod_stop();
+}
+
+static const struct seq_operations show_format_seq_ops = {
+	.start = t_start,
+	.next = t_next,
+	.show = t_show,
+	.stop = t_stop,
+};
+
+static int
+ftrace_formats_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	return seq_open(file, &show_format_seq_ops);
+}
+
+static const struct file_operations ftrace_formats_fops = {
+	.open = ftrace_formats_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+static __init int init_trace_printk_function_export(void)
+{
+	int ret;
+
+	ret = tracing_init_dentry();
+	if (ret)
+		return 0;
+
+	trace_create_file("printk_formats", TRACE_MODE_READ, NULL,
+				    NULL, &ftrace_formats_fops);
+
+	return 0;
+}
+
+fs_initcall(init_trace_printk_function_export);
+
+static __init int init_trace_printk(void)
+{
+	return register_module_notifier(&module_trace_bprintk_format_nb);
+}
+
+early_initcall(init_trace_printk);
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
new file mode 100644
index 000000000..eef9806bb
--- /dev/null
+++ b/kernel/trace/trace_probe.c
@@ -0,0 +1,1234 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Common code for probe-based Dynamic events.
+ *
+ * This code was copied from kernel/trace/trace_kprobe.c written by
+ * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
+ *
+ * Updates to make this generic:
+ * Copyright (C) IBM Corporation, 2010-2011
+ * Author:     Srikar Dronamraju
+ */
+#define pr_fmt(fmt)	"trace_probe: " fmt
+
+#include "trace_probe.h"
+
+#undef C
+#define C(a, b)		b
+
+static const char *trace_probe_err_text[] = { ERRORS };
+
+static const char *reserved_field_names[] = {
+	"common_type",
+	"common_flags",
+	"common_preempt_count",
+	"common_pid",
+	"common_tgid",
+	FIELD_STRING_IP,
+	FIELD_STRING_RETIP,
+	FIELD_STRING_FUNC,
+};
+
+/* Printing  in basic type function template */
+#define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt)			\
+int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
+{									\
+	trace_seq_printf(s, fmt, *(type *)data);			\
+	return !trace_seq_has_overflowed(s);				\
+}									\
+const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
+
+DEFINE_BASIC_PRINT_TYPE_FUNC(u8,  u8,  "%u")
+DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
+DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
+DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
+DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  s8,  "%d")
+DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
+DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
+DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
+DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
+DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
+DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
+DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
+
+int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
+{
+	trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
+	return !trace_seq_has_overflowed(s);
+}
+const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
+
+/* Print type function for string type */
+int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
+{
+	int len = *(u32 *)data >> 16;
+
+	if (!len)
+		trace_seq_puts(s, FAULT_STRING);
+	else
+		trace_seq_printf(s, "\"%s\"",
+				 (const char *)get_loc_data(data, ent));
+	return !trace_seq_has_overflowed(s);
+}
+
+const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
+
+/* Fetch type information table */
+static const struct fetch_type probe_fetch_types[] = {
+	/* Special types */
+	__ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1,
+			    "__data_loc char[]"),
+	__ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
+			    "__data_loc char[]"),
+	__ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1,
+			    "__data_loc char[]"),
+	/* Basic types */
+	ASSIGN_FETCH_TYPE(u8,  u8,  0),
+	ASSIGN_FETCH_TYPE(u16, u16, 0),
+	ASSIGN_FETCH_TYPE(u32, u32, 0),
+	ASSIGN_FETCH_TYPE(u64, u64, 0),
+	ASSIGN_FETCH_TYPE(s8,  u8,  1),
+	ASSIGN_FETCH_TYPE(s16, u16, 1),
+	ASSIGN_FETCH_TYPE(s32, u32, 1),
+	ASSIGN_FETCH_TYPE(s64, u64, 1),
+	ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
+	ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
+	ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
+	ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
+	ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
+
+	ASSIGN_FETCH_TYPE_END
+};
+
+static const struct fetch_type *find_fetch_type(const char *type)
+{
+	int i;
+
+	if (!type)
+		type = DEFAULT_FETCH_TYPE_STR;
+
+	/* Special case: bitfield */
+	if (*type == 'b') {
+		unsigned long bs;
+
+		type = strchr(type, '/');
+		if (!type)
+			goto fail;
+
+		type++;
+		if (kstrtoul(type, 0, &bs))
+			goto fail;
+
+		switch (bs) {
+		case 8:
+			return find_fetch_type("u8");
+		case 16:
+			return find_fetch_type("u16");
+		case 32:
+			return find_fetch_type("u32");
+		case 64:
+			return find_fetch_type("u64");
+		default:
+			goto fail;
+		}
+	}
+
+	for (i = 0; probe_fetch_types[i].name; i++) {
+		if (strcmp(type, probe_fetch_types[i].name) == 0)
+			return &probe_fetch_types[i];
+	}
+
+fail:
+	return NULL;
+}
+
+static struct trace_probe_log trace_probe_log;
+
+void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
+{
+	trace_probe_log.subsystem = subsystem;
+	trace_probe_log.argc = argc;
+	trace_probe_log.argv = argv;
+	trace_probe_log.index = 0;
+}
+
+void trace_probe_log_clear(void)
+{
+	memset(&trace_probe_log, 0, sizeof(trace_probe_log));
+}
+
+void trace_probe_log_set_index(int index)
+{
+	trace_probe_log.index = index;
+}
+
+void __trace_probe_log_err(int offset, int err_type)
+{
+	char *command, *p;
+	int i, len = 0, pos = 0;
+
+	if (!trace_probe_log.argv)
+		return;
+
+	/* Recalculate the length and allocate buffer */
+	for (i = 0; i < trace_probe_log.argc; i++) {
+		if (i == trace_probe_log.index)
+			pos = len;
+		len += strlen(trace_probe_log.argv[i]) + 1;
+	}
+	command = kzalloc(len, GFP_KERNEL);
+	if (!command)
+		return;
+
+	if (trace_probe_log.index >= trace_probe_log.argc) {
+		/**
+		 * Set the error position is next to the last arg + space.
+		 * Note that len includes the terminal null and the cursor
+		 * appears at pos + 1.
+		 */
+		pos = len;
+		offset = 0;
+	}
+
+	/* And make a command string from argv array */
+	p = command;
+	for (i = 0; i < trace_probe_log.argc; i++) {
+		len = strlen(trace_probe_log.argv[i]);
+		strcpy(p, trace_probe_log.argv[i]);
+		p[len] = ' ';
+		p += len + 1;
+	}
+	*(p - 1) = '\0';
+
+	tracing_log_err(NULL, trace_probe_log.subsystem, command,
+			trace_probe_err_text, err_type, pos + offset);
+
+	kfree(command);
+}
+
+/* Split symbol and offset. */
+int traceprobe_split_symbol_offset(char *symbol, long *offset)
+{
+	char *tmp;
+	int ret;
+
+	if (!offset)
+		return -EINVAL;
+
+	tmp = strpbrk(symbol, "+-");
+	if (tmp) {
+		ret = kstrtol(tmp, 0, offset);
+		if (ret)
+			return ret;
+		*tmp = '\0';
+	} else
+		*offset = 0;
+
+	return 0;
+}
+
+/* @buf must has MAX_EVENT_NAME_LEN size */
+int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
+				char *buf, int offset)
+{
+	const char *slash, *event = *pevent;
+	int len;
+
+	slash = strchr(event, '/');
+	if (!slash)
+		slash = strchr(event, '.');
+
+	if (slash) {
+		if (slash == event) {
+			trace_probe_log_err(offset, NO_GROUP_NAME);
+			return -EINVAL;
+		}
+		if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
+			trace_probe_log_err(offset, GROUP_TOO_LONG);
+			return -EINVAL;
+		}
+		strlcpy(buf, event, slash - event + 1);
+		if (!is_good_system_name(buf)) {
+			trace_probe_log_err(offset, BAD_GROUP_NAME);
+			return -EINVAL;
+		}
+		*pgroup = buf;
+		*pevent = slash + 1;
+		offset += slash - event + 1;
+		event = *pevent;
+	}
+	len = strlen(event);
+	if (len == 0) {
+		if (slash) {
+			*pevent = NULL;
+			return 0;
+		}
+		trace_probe_log_err(offset, NO_EVENT_NAME);
+		return -EINVAL;
+	} else if (len > MAX_EVENT_NAME_LEN) {
+		trace_probe_log_err(offset, EVENT_TOO_LONG);
+		return -EINVAL;
+	}
+	if (!is_good_name(event)) {
+		trace_probe_log_err(offset, BAD_EVENT_NAME);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
+
+static int parse_probe_vars(char *arg, const struct fetch_type *t,
+			struct fetch_insn *code, unsigned int flags, int offs)
+{
+	unsigned long param;
+	int ret = 0;
+	int len;
+
+	if (flags & TPARG_FL_TPOINT) {
+		if (code->data)
+			return -EFAULT;
+		code->data = kstrdup(arg, GFP_KERNEL);
+		if (!code->data)
+			return -ENOMEM;
+		code->op = FETCH_OP_TP_ARG;
+	} else if (strcmp(arg, "retval") == 0) {
+		if (flags & TPARG_FL_RETURN) {
+			code->op = FETCH_OP_RETVAL;
+		} else {
+			trace_probe_log_err(offs, RETVAL_ON_PROBE);
+			ret = -EINVAL;
+		}
+	} else if ((len = str_has_prefix(arg, "stack"))) {
+		if (arg[len] == '\0') {
+			code->op = FETCH_OP_STACKP;
+		} else if (isdigit(arg[len])) {
+			ret = kstrtoul(arg + len, 10, &param);
+			if (ret) {
+				goto inval_var;
+			} else if ((flags & TPARG_FL_KERNEL) &&
+				    param > PARAM_MAX_STACK) {
+				trace_probe_log_err(offs, BAD_STACK_NUM);
+				ret = -EINVAL;
+			} else {
+				code->op = FETCH_OP_STACK;
+				code->param = (unsigned int)param;
+			}
+		} else
+			goto inval_var;
+	} else if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
+		code->op = FETCH_OP_COMM;
+#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
+	} else if (((flags & TPARG_FL_MASK) ==
+		    (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) &&
+		   (len = str_has_prefix(arg, "arg"))) {
+		ret = kstrtoul(arg + len, 10, &param);
+		if (ret) {
+			goto inval_var;
+		} else if (!param || param > PARAM_MAX_STACK) {
+			trace_probe_log_err(offs, BAD_ARG_NUM);
+			return -EINVAL;
+		}
+		code->op = FETCH_OP_ARG;
+		code->param = (unsigned int)param - 1;
+#endif
+	} else
+		goto inval_var;
+
+	return ret;
+
+inval_var:
+	trace_probe_log_err(offs, BAD_VAR);
+	return -EINVAL;
+}
+
+static int str_to_immediate(char *str, unsigned long *imm)
+{
+	if (isdigit(str[0]))
+		return kstrtoul(str, 0, imm);
+	else if (str[0] == '-')
+		return kstrtol(str, 0, (long *)imm);
+	else if (str[0] == '+')
+		return kstrtol(str + 1, 0, (long *)imm);
+	return -EINVAL;
+}
+
+static int __parse_imm_string(char *str, char **pbuf, int offs)
+{
+	size_t len = strlen(str);
+
+	if (str[len - 1] != '"') {
+		trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
+		return -EINVAL;
+	}
+	*pbuf = kstrndup(str, len - 1, GFP_KERNEL);
+	if (!*pbuf)
+		return -ENOMEM;
+	return 0;
+}
+
+/* Recursive argument parser */
+static int
+parse_probe_arg(char *arg, const struct fetch_type *type,
+		struct fetch_insn **pcode, struct fetch_insn *end,
+		unsigned int flags, int offs)
+{
+	struct fetch_insn *code = *pcode;
+	unsigned long param;
+	int deref = FETCH_OP_DEREF;
+	long offset = 0;
+	char *tmp;
+	int ret = 0;
+
+	switch (arg[0]) {
+	case '$':
+		ret = parse_probe_vars(arg + 1, type, code, flags, offs);
+		break;
+
+	case '%':	/* named register */
+		if (flags & TPARG_FL_TPOINT) {
+			/* eprobes do not handle registers */
+			trace_probe_log_err(offs, BAD_VAR);
+			break;
+		}
+		ret = regs_query_register_offset(arg + 1);
+		if (ret >= 0) {
+			code->op = FETCH_OP_REG;
+			code->param = (unsigned int)ret;
+			ret = 0;
+		} else
+			trace_probe_log_err(offs, BAD_REG_NAME);
+		break;
+
+	case '@':	/* memory, file-offset or symbol */
+		if (isdigit(arg[1])) {
+			ret = kstrtoul(arg + 1, 0, &param);
+			if (ret) {
+				trace_probe_log_err(offs, BAD_MEM_ADDR);
+				break;
+			}
+			/* load address */
+			code->op = FETCH_OP_IMM;
+			code->immediate = param;
+		} else if (arg[1] == '+') {
+			/* kprobes don't support file offsets */
+			if (flags & TPARG_FL_KERNEL) {
+				trace_probe_log_err(offs, FILE_ON_KPROBE);
+				return -EINVAL;
+			}
+			ret = kstrtol(arg + 2, 0, &offset);
+			if (ret) {
+				trace_probe_log_err(offs, BAD_FILE_OFFS);
+				break;
+			}
+
+			code->op = FETCH_OP_FOFFS;
+			code->immediate = (unsigned long)offset;  // imm64?
+		} else {
+			/* uprobes don't support symbols */
+			if (!(flags & TPARG_FL_KERNEL)) {
+				trace_probe_log_err(offs, SYM_ON_UPROBE);
+				return -EINVAL;
+			}
+			/* Preserve symbol for updating */
+			code->op = FETCH_NOP_SYMBOL;
+			code->data = kstrdup(arg + 1, GFP_KERNEL);
+			if (!code->data)
+				return -ENOMEM;
+			if (++code == end) {
+				trace_probe_log_err(offs, TOO_MANY_OPS);
+				return -EINVAL;
+			}
+			code->op = FETCH_OP_IMM;
+			code->immediate = 0;
+		}
+		/* These are fetching from memory */
+		if (++code == end) {
+			trace_probe_log_err(offs, TOO_MANY_OPS);
+			return -EINVAL;
+		}
+		*pcode = code;
+		code->op = FETCH_OP_DEREF;
+		code->offset = offset;
+		break;
+
+	case '+':	/* deref memory */
+	case '-':
+		if (arg[1] == 'u') {
+			deref = FETCH_OP_UDEREF;
+			arg[1] = arg[0];
+			arg++;
+		}
+		if (arg[0] == '+')
+			arg++;	/* Skip '+', because kstrtol() rejects it. */
+		tmp = strchr(arg, '(');
+		if (!tmp) {
+			trace_probe_log_err(offs, DEREF_NEED_BRACE);
+			return -EINVAL;
+		}
+		*tmp = '\0';
+		ret = kstrtol(arg, 0, &offset);
+		if (ret) {
+			trace_probe_log_err(offs, BAD_DEREF_OFFS);
+			break;
+		}
+		offs += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
+		arg = tmp + 1;
+		tmp = strrchr(arg, ')');
+		if (!tmp) {
+			trace_probe_log_err(offs + strlen(arg),
+					    DEREF_OPEN_BRACE);
+			return -EINVAL;
+		} else {
+			const struct fetch_type *t2 = find_fetch_type(NULL);
+
+			*tmp = '\0';
+			ret = parse_probe_arg(arg, t2, &code, end, flags, offs);
+			if (ret)
+				break;
+			if (code->op == FETCH_OP_COMM ||
+			    code->op == FETCH_OP_DATA) {
+				trace_probe_log_err(offs, COMM_CANT_DEREF);
+				return -EINVAL;
+			}
+			if (++code == end) {
+				trace_probe_log_err(offs, TOO_MANY_OPS);
+				return -EINVAL;
+			}
+			*pcode = code;
+
+			code->op = deref;
+			code->offset = offset;
+		}
+		break;
+	case '\\':	/* Immediate value */
+		if (arg[1] == '"') {	/* Immediate string */
+			ret = __parse_imm_string(arg + 2, &tmp, offs + 2);
+			if (ret)
+				break;
+			code->op = FETCH_OP_DATA;
+			code->data = tmp;
+		} else {
+			ret = str_to_immediate(arg + 1, &code->immediate);
+			if (ret)
+				trace_probe_log_err(offs + 1, BAD_IMM);
+			else
+				code->op = FETCH_OP_IMM;
+		}
+		break;
+	}
+	if (!ret && code->op == FETCH_OP_NOP) {
+		/* Parsed, but do not find fetch method */
+		trace_probe_log_err(offs, BAD_FETCH_ARG);
+		ret = -EINVAL;
+	}
+	return ret;
+}
+
+#define BYTES_TO_BITS(nb)	((BITS_PER_LONG * (nb)) / sizeof(long))
+
+/* Bitfield type needs to be parsed into a fetch function */
+static int __parse_bitfield_probe_arg(const char *bf,
+				      const struct fetch_type *t,
+				      struct fetch_insn **pcode)
+{
+	struct fetch_insn *code = *pcode;
+	unsigned long bw, bo;
+	char *tail;
+
+	if (*bf != 'b')
+		return 0;
+
+	bw = simple_strtoul(bf + 1, &tail, 0);	/* Use simple one */
+
+	if (bw == 0 || *tail != '@')
+		return -EINVAL;
+
+	bf = tail + 1;
+	bo = simple_strtoul(bf, &tail, 0);
+
+	if (tail == bf || *tail != '/')
+		return -EINVAL;
+	code++;
+	if (code->op != FETCH_OP_NOP)
+		return -EINVAL;
+	*pcode = code;
+
+	code->op = FETCH_OP_MOD_BF;
+	code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
+	code->rshift = BYTES_TO_BITS(t->size) - bw;
+	code->basesize = t->size;
+
+	return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
+}
+
+/* String length checking wrapper */
+static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
+		struct probe_arg *parg, unsigned int flags, int offset)
+{
+	struct fetch_insn *code, *scode, *tmp = NULL;
+	char *t, *t2, *t3;
+	char *arg;
+	int ret, len;
+
+	arg = kstrdup(argv, GFP_KERNEL);
+	if (!arg)
+		return -ENOMEM;
+
+	ret = -EINVAL;
+	len = strlen(arg);
+	if (len > MAX_ARGSTR_LEN) {
+		trace_probe_log_err(offset, ARG_TOO_LONG);
+		goto out;
+	} else if (len == 0) {
+		trace_probe_log_err(offset, NO_ARG_BODY);
+		goto out;
+	}
+
+	ret = -ENOMEM;
+	parg->comm = kstrdup(arg, GFP_KERNEL);
+	if (!parg->comm)
+		goto out;
+
+	ret = -EINVAL;
+	t = strchr(arg, ':');
+	if (t) {
+		*t = '\0';
+		t2 = strchr(++t, '[');
+		if (t2) {
+			*t2++ = '\0';
+			t3 = strchr(t2, ']');
+			if (!t3) {
+				offset += t2 + strlen(t2) - arg;
+				trace_probe_log_err(offset,
+						    ARRAY_NO_CLOSE);
+				goto out;
+			} else if (t3[1] != '\0') {
+				trace_probe_log_err(offset + t3 + 1 - arg,
+						    BAD_ARRAY_SUFFIX);
+				goto out;
+			}
+			*t3 = '\0';
+			if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
+				trace_probe_log_err(offset + t2 - arg,
+						    BAD_ARRAY_NUM);
+				goto out;
+			}
+			if (parg->count > MAX_ARRAY_LEN) {
+				trace_probe_log_err(offset + t2 - arg,
+						    ARRAY_TOO_BIG);
+				goto out;
+			}
+		}
+	}
+
+	/*
+	 * Since $comm and immediate string can not be dereferenced,
+	 * we can find those by strcmp. But ignore for eprobes.
+	 */
+	if (!(flags & TPARG_FL_TPOINT) &&
+	    (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
+	     strncmp(arg, "\\\"", 2) == 0)) {
+		/* The type of $comm must be "string", and not an array. */
+		if (parg->count || (t && strcmp(t, "string")))
+			goto out;
+		parg->type = find_fetch_type("string");
+	} else
+		parg->type = find_fetch_type(t);
+	if (!parg->type) {
+		trace_probe_log_err(offset + (t ? (t - arg) : 0), BAD_TYPE);
+		goto out;
+	}
+	parg->offset = *size;
+	*size += parg->type->size * (parg->count ?: 1);
+
+	ret = -ENOMEM;
+	if (parg->count) {
+		len = strlen(parg->type->fmttype) + 6;
+		parg->fmt = kmalloc(len, GFP_KERNEL);
+		if (!parg->fmt)
+			goto out;
+		snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
+			 parg->count);
+	}
+
+	code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
+	if (!code)
+		goto out;
+	code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
+
+	ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
+			      flags, offset);
+	if (ret)
+		goto fail;
+
+	ret = -EINVAL;
+	/* Store operation */
+	if (parg->type->is_string) {
+		if (!strcmp(parg->type->name, "symstr")) {
+			if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
+			    code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
+			    code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
+				trace_probe_log_err(offset + (t ? (t - arg) : 0),
+						    BAD_SYMSTRING);
+				goto fail;
+			}
+		} else {
+			if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
+			    code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
+			    code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
+				trace_probe_log_err(offset + (t ? (t - arg) : 0),
+						    BAD_STRING);
+				goto fail;
+			}
+		}
+		if (!strcmp(parg->type->name, "symstr") ||
+		    (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
+		     code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
+		     parg->count) {
+			/*
+			 * IMM, DATA and COMM is pointing actual address, those
+			 * must be kept, and if parg->count != 0, this is an
+			 * array of string pointers instead of string address
+			 * itself.
+			 * For the symstr, it doesn't need to dereference, thus
+			 * it just get the value.
+			 */
+			code++;
+			if (code->op != FETCH_OP_NOP) {
+				trace_probe_log_err(offset, TOO_MANY_OPS);
+				goto fail;
+			}
+		}
+		/* If op == DEREF, replace it with STRING */
+		if (!strcmp(parg->type->name, "ustring") ||
+		    code->op == FETCH_OP_UDEREF)
+			code->op = FETCH_OP_ST_USTRING;
+		else if (!strcmp(parg->type->name, "symstr"))
+			code->op = FETCH_OP_ST_SYMSTR;
+		else
+			code->op = FETCH_OP_ST_STRING;
+		code->size = parg->type->size;
+		parg->dynamic = true;
+	} else if (code->op == FETCH_OP_DEREF) {
+		code->op = FETCH_OP_ST_MEM;
+		code->size = parg->type->size;
+	} else if (code->op == FETCH_OP_UDEREF) {
+		code->op = FETCH_OP_ST_UMEM;
+		code->size = parg->type->size;
+	} else {
+		code++;
+		if (code->op != FETCH_OP_NOP) {
+			trace_probe_log_err(offset, TOO_MANY_OPS);
+			goto fail;
+		}
+		code->op = FETCH_OP_ST_RAW;
+		code->size = parg->type->size;
+	}
+	scode = code;
+	/* Modify operation */
+	if (t != NULL) {
+		ret = __parse_bitfield_probe_arg(t, parg->type, &code);
+		if (ret) {
+			trace_probe_log_err(offset + t - arg, BAD_BITFIELD);
+			goto fail;
+		}
+	}
+	ret = -EINVAL;
+	/* Loop(Array) operation */
+	if (parg->count) {
+		if (scode->op != FETCH_OP_ST_MEM &&
+		    scode->op != FETCH_OP_ST_STRING &&
+		    scode->op != FETCH_OP_ST_USTRING) {
+			trace_probe_log_err(offset + (t ? (t - arg) : 0),
+					    BAD_STRING);
+			goto fail;
+		}
+		code++;
+		if (code->op != FETCH_OP_NOP) {
+			trace_probe_log_err(offset, TOO_MANY_OPS);
+			goto fail;
+		}
+		code->op = FETCH_OP_LP_ARRAY;
+		code->param = parg->count;
+	}
+	code++;
+	code->op = FETCH_OP_END;
+
+	ret = 0;
+	/* Shrink down the code buffer */
+	parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
+	if (!parg->code)
+		ret = -ENOMEM;
+	else
+		memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
+
+fail:
+	if (ret) {
+		for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
+			if (code->op == FETCH_NOP_SYMBOL ||
+			    code->op == FETCH_OP_DATA)
+				kfree(code->data);
+	}
+	kfree(tmp);
+out:
+	kfree(arg);
+
+	return ret;
+}
+
+/* Return 1 if name is reserved or already used by another argument */
+static int traceprobe_conflict_field_name(const char *name,
+					  struct probe_arg *args, int narg)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
+		if (strcmp(reserved_field_names[i], name) == 0)
+			return 1;
+
+	for (i = 0; i < narg; i++)
+		if (strcmp(args[i].name, name) == 0)
+			return 1;
+
+	return 0;
+}
+
+int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
+				unsigned int flags)
+{
+	struct probe_arg *parg = &tp->args[i];
+	const char *body;
+
+	/* Increment count for freeing args in error case */
+	tp->nr_args++;
+
+	body = strchr(arg, '=');
+	if (body) {
+		if (body - arg > MAX_ARG_NAME_LEN) {
+			trace_probe_log_err(0, ARG_NAME_TOO_LONG);
+			return -EINVAL;
+		} else if (body == arg) {
+			trace_probe_log_err(0, NO_ARG_NAME);
+			return -EINVAL;
+		}
+		parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
+		body++;
+	} else {
+		/* If argument name is omitted, set "argN" */
+		parg->name = kasprintf(GFP_KERNEL, "arg%d", i + 1);
+		body = arg;
+	}
+	if (!parg->name)
+		return -ENOMEM;
+
+	if (!is_good_name(parg->name)) {
+		trace_probe_log_err(0, BAD_ARG_NAME);
+		return -EINVAL;
+	}
+	if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
+		trace_probe_log_err(0, USED_ARG_NAME);
+		return -EINVAL;
+	}
+	/* Parse fetch argument */
+	return traceprobe_parse_probe_arg_body(body, &tp->size, parg, flags,
+					       body - arg);
+}
+
+void traceprobe_free_probe_arg(struct probe_arg *arg)
+{
+	struct fetch_insn *code = arg->code;
+
+	while (code && code->op != FETCH_OP_END) {
+		if (code->op == FETCH_NOP_SYMBOL ||
+		    code->op == FETCH_OP_DATA)
+			kfree(code->data);
+		code++;
+	}
+	kfree(arg->code);
+	kfree(arg->name);
+	kfree(arg->comm);
+	kfree(arg->fmt);
+}
+
+int traceprobe_update_arg(struct probe_arg *arg)
+{
+	struct fetch_insn *code = arg->code;
+	long offset;
+	char *tmp;
+	char c;
+	int ret = 0;
+
+	while (code && code->op != FETCH_OP_END) {
+		if (code->op == FETCH_NOP_SYMBOL) {
+			if (code[1].op != FETCH_OP_IMM)
+				return -EINVAL;
+
+			tmp = strpbrk(code->data, "+-");
+			if (tmp)
+				c = *tmp;
+			ret = traceprobe_split_symbol_offset(code->data,
+							     &offset);
+			if (ret)
+				return ret;
+
+			code[1].immediate =
+				(unsigned long)kallsyms_lookup_name(code->data);
+			if (tmp)
+				*tmp = c;
+			if (!code[1].immediate)
+				return -ENOENT;
+			code[1].immediate += offset;
+		}
+		code++;
+	}
+	return 0;
+}
+
+/* When len=0, we just calculate the needed length */
+#define LEN_OR_ZERO (len ? len - pos : 0)
+static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
+			   enum probe_print_type ptype)
+{
+	struct probe_arg *parg;
+	int i, j;
+	int pos = 0;
+	const char *fmt, *arg;
+
+	switch (ptype) {
+	case PROBE_PRINT_NORMAL:
+		fmt = "(%lx)";
+		arg = ", REC->" FIELD_STRING_IP;
+		break;
+	case PROBE_PRINT_RETURN:
+		fmt = "(%lx <- %lx)";
+		arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
+		break;
+	case PROBE_PRINT_EVENT:
+		fmt = "";
+		arg = "";
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		return 0;
+	}
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
+
+	for (i = 0; i < tp->nr_args; i++) {
+		parg = tp->args + i;
+		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
+		if (parg->count) {
+			pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
+					parg->type->fmt);
+			for (j = 1; j < parg->count; j++)
+				pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
+						parg->type->fmt);
+			pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
+		} else
+			pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
+					parg->type->fmt);
+	}
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
+
+	for (i = 0; i < tp->nr_args; i++) {
+		parg = tp->args + i;
+		if (parg->count) {
+			if (parg->type->is_string)
+				fmt = ", __get_str(%s[%d])";
+			else
+				fmt = ", REC->%s[%d]";
+			for (j = 0; j < parg->count; j++)
+				pos += snprintf(buf + pos, LEN_OR_ZERO,
+						fmt, parg->name, j);
+		} else {
+			if (parg->type->is_string)
+				fmt = ", __get_str(%s)";
+			else
+				fmt = ", REC->%s";
+			pos += snprintf(buf + pos, LEN_OR_ZERO,
+					fmt, parg->name);
+		}
+	}
+
+	/* return the length of print_fmt */
+	return pos;
+}
+#undef LEN_OR_ZERO
+
+int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
+{
+	struct trace_event_call *call = trace_probe_event_call(tp);
+	int len;
+	char *print_fmt;
+
+	/* First: called with 0 length to calculate the needed length */
+	len = __set_print_fmt(tp, NULL, 0, ptype);
+	print_fmt = kmalloc(len + 1, GFP_KERNEL);
+	if (!print_fmt)
+		return -ENOMEM;
+
+	/* Second: actually write the @print_fmt */
+	__set_print_fmt(tp, print_fmt, len + 1, ptype);
+	call->print_fmt = print_fmt;
+
+	return 0;
+}
+
+int traceprobe_define_arg_fields(struct trace_event_call *event_call,
+				 size_t offset, struct trace_probe *tp)
+{
+	int ret, i;
+
+	/* Set argument names as fields */
+	for (i = 0; i < tp->nr_args; i++) {
+		struct probe_arg *parg = &tp->args[i];
+		const char *fmt = parg->type->fmttype;
+		int size = parg->type->size;
+
+		if (parg->fmt)
+			fmt = parg->fmt;
+		if (parg->count)
+			size *= parg->count;
+		ret = trace_define_field(event_call, fmt, parg->name,
+					 offset + parg->offset, size,
+					 parg->type->is_signed,
+					 FILTER_OTHER);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+static void trace_probe_event_free(struct trace_probe_event *tpe)
+{
+	kfree(tpe->class.system);
+	kfree(tpe->call.name);
+	kfree(tpe->call.print_fmt);
+	kfree(tpe);
+}
+
+int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
+{
+	if (trace_probe_has_sibling(tp))
+		return -EBUSY;
+
+	list_del_init(&tp->list);
+	trace_probe_event_free(tp->event);
+
+	tp->event = to->event;
+	list_add_tail(&tp->list, trace_probe_probe_list(to));
+
+	return 0;
+}
+
+void trace_probe_unlink(struct trace_probe *tp)
+{
+	list_del_init(&tp->list);
+	if (list_empty(trace_probe_probe_list(tp)))
+		trace_probe_event_free(tp->event);
+	tp->event = NULL;
+}
+
+void trace_probe_cleanup(struct trace_probe *tp)
+{
+	int i;
+
+	for (i = 0; i < tp->nr_args; i++)
+		traceprobe_free_probe_arg(&tp->args[i]);
+
+	if (tp->event)
+		trace_probe_unlink(tp);
+}
+
+int trace_probe_init(struct trace_probe *tp, const char *event,
+		     const char *group, bool alloc_filter)
+{
+	struct trace_event_call *call;
+	size_t size = sizeof(struct trace_probe_event);
+	int ret = 0;
+
+	if (!event || !group)
+		return -EINVAL;
+
+	if (alloc_filter)
+		size += sizeof(struct trace_uprobe_filter);
+
+	tp->event = kzalloc(size, GFP_KERNEL);
+	if (!tp->event)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&tp->event->files);
+	INIT_LIST_HEAD(&tp->event->class.fields);
+	INIT_LIST_HEAD(&tp->event->probes);
+	INIT_LIST_HEAD(&tp->list);
+	list_add(&tp->list, &tp->event->probes);
+
+	call = trace_probe_event_call(tp);
+	call->class = &tp->event->class;
+	call->name = kstrdup(event, GFP_KERNEL);
+	if (!call->name) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	tp->event->class.system = kstrdup(group, GFP_KERNEL);
+	if (!tp->event->class.system) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	return 0;
+
+error:
+	trace_probe_cleanup(tp);
+	return ret;
+}
+
+static struct trace_event_call *
+find_trace_event_call(const char *system, const char *event_name)
+{
+	struct trace_event_call *tp_event;
+	const char *name;
+
+	list_for_each_entry(tp_event, &ftrace_events, list) {
+		if (!tp_event->class->system ||
+		    strcmp(system, tp_event->class->system))
+			continue;
+		name = trace_event_name(tp_event);
+		if (!name || strcmp(event_name, name))
+			continue;
+		return tp_event;
+	}
+
+	return NULL;
+}
+
+int trace_probe_register_event_call(struct trace_probe *tp)
+{
+	struct trace_event_call *call = trace_probe_event_call(tp);
+	int ret;
+
+	lockdep_assert_held(&event_mutex);
+
+	if (find_trace_event_call(trace_probe_group_name(tp),
+				  trace_probe_name(tp)))
+		return -EEXIST;
+
+	ret = register_trace_event(&call->event);
+	if (!ret)
+		return -ENODEV;
+
+	ret = trace_add_event_call(call);
+	if (ret)
+		unregister_trace_event(&call->event);
+
+	return ret;
+}
+
+int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
+{
+	struct event_file_link *link;
+
+	link = kmalloc(sizeof(*link), GFP_KERNEL);
+	if (!link)
+		return -ENOMEM;
+
+	link->file = file;
+	INIT_LIST_HEAD(&link->list);
+	list_add_tail_rcu(&link->list, &tp->event->files);
+	trace_probe_set_flag(tp, TP_FLAG_TRACE);
+	return 0;
+}
+
+struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
+						  struct trace_event_file *file)
+{
+	struct event_file_link *link;
+
+	trace_probe_for_each_link(link, tp) {
+		if (link->file == file)
+			return link;
+	}
+
+	return NULL;
+}
+
+int trace_probe_remove_file(struct trace_probe *tp,
+			    struct trace_event_file *file)
+{
+	struct event_file_link *link;
+
+	link = trace_probe_get_file_link(tp, file);
+	if (!link)
+		return -ENOENT;
+
+	list_del_rcu(&link->list);
+	kvfree_rcu(link);
+
+	if (list_empty(&tp->event->files))
+		trace_probe_clear_flag(tp, TP_FLAG_TRACE);
+
+	return 0;
+}
+
+/*
+ * Return the smallest index of different type argument (start from 1).
+ * If all argument types and name are same, return 0.
+ */
+int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
+{
+	int i;
+
+	/* In case of more arguments */
+	if (a->nr_args < b->nr_args)
+		return a->nr_args + 1;
+	if (a->nr_args > b->nr_args)
+		return b->nr_args + 1;
+
+	for (i = 0; i < a->nr_args; i++) {
+		if ((b->nr_args <= i) ||
+		    ((a->args[i].type != b->args[i].type) ||
+		     (a->args[i].count != b->args[i].count) ||
+		     strcmp(a->args[i].name, b->args[i].name)))
+			return i + 1;
+	}
+
+	return 0;
+}
+
+bool trace_probe_match_command_args(struct trace_probe *tp,
+				    int argc, const char **argv)
+{
+	char buf[MAX_ARGSTR_LEN + 1];
+	int i;
+
+	if (tp->nr_args < argc)
+		return false;
+
+	for (i = 0; i < argc; i++) {
+		snprintf(buf, sizeof(buf), "%s=%s",
+			 tp->args[i].name, tp->args[i].comm);
+		if (strcmp(buf, argv[i]))
+			return false;
+	}
+	return true;
+}
+
+int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
+{
+	int argc = 0, ret = 0;
+	char **argv;
+
+	argv = argv_split(GFP_KERNEL, raw_command, &argc);
+	if (!argv)
+		return -ENOMEM;
+
+	if (argc)
+		ret = createfn(argc, (const char **)argv);
+
+	argv_free(argv);
+
+	return ret;
+}
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
new file mode 100644
index 000000000..f48b3ed20
--- /dev/null
+++ b/kernel/trace/trace_probe.h
@@ -0,0 +1,479 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Common header file for probe-based Dynamic events.
+ *
+ * This code was copied from kernel/trace/trace_kprobe.h written by
+ * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
+ *
+ * Updates to make this generic:
+ * Copyright (C) IBM Corporation, 2010-2011
+ * Author:     Srikar Dronamraju
+ */
+
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+#include <linux/tracefs.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/ptrace.h>
+#include <linux/perf_event.h>
+#include <linux/kprobes.h>
+#include <linux/stringify.h>
+#include <linux/limits.h>
+#include <linux/uaccess.h>
+#include <linux/bitops.h>
+#include <asm/bitsperlong.h>
+
+#include "trace.h"
+#include "trace_output.h"
+
+#define MAX_TRACE_ARGS		128
+#define MAX_ARGSTR_LEN		63
+#define MAX_ARRAY_LEN		64
+#define MAX_ARG_NAME_LEN	32
+#define MAX_STRING_SIZE		PATH_MAX
+
+/* Reserved field names */
+#define FIELD_STRING_IP		"__probe_ip"
+#define FIELD_STRING_RETIP	"__probe_ret_ip"
+#define FIELD_STRING_FUNC	"__probe_func"
+
+#undef DEFINE_FIELD
+#define DEFINE_FIELD(type, item, name, is_signed)			\
+	do {								\
+		ret = trace_define_field(event_call, #type, name,	\
+					 offsetof(typeof(field), item),	\
+					 sizeof(field.item), is_signed, \
+					 FILTER_OTHER);			\
+		if (ret)						\
+			return ret;					\
+	} while (0)
+
+
+/* Flags for trace_probe */
+#define TP_FLAG_TRACE		1
+#define TP_FLAG_PROFILE		2
+
+/* data_loc: data location, compatible with u32 */
+#define make_data_loc(len, offs)	\
+	(((u32)(len) << 16) | ((u32)(offs) & 0xffff))
+#define get_loc_len(dl)		((u32)(dl) >> 16)
+#define get_loc_offs(dl)	((u32)(dl) & 0xffff)
+
+static nokprobe_inline void *get_loc_data(u32 *dl, void *ent)
+{
+	return (u8 *)ent + get_loc_offs(*dl);
+}
+
+static nokprobe_inline u32 update_data_loc(u32 loc, int consumed)
+{
+	u32 maxlen = get_loc_len(loc);
+	u32 offset = get_loc_offs(loc);
+
+	return make_data_loc(maxlen - consumed, offset + consumed);
+}
+
+/* Printing function type */
+typedef int (*print_type_func_t)(struct trace_seq *, void *, void *);
+
+enum fetch_op {
+	FETCH_OP_NOP = 0,
+	// Stage 1 (load) ops
+	FETCH_OP_REG,		/* Register : .param = offset */
+	FETCH_OP_STACK,		/* Stack : .param = index */
+	FETCH_OP_STACKP,	/* Stack pointer */
+	FETCH_OP_RETVAL,	/* Return value */
+	FETCH_OP_IMM,		/* Immediate : .immediate */
+	FETCH_OP_COMM,		/* Current comm */
+	FETCH_OP_ARG,		/* Function argument : .param */
+	FETCH_OP_FOFFS,		/* File offset: .immediate */
+	FETCH_OP_DATA,		/* Allocated data: .data */
+	// Stage 2 (dereference) op
+	FETCH_OP_DEREF,		/* Dereference: .offset */
+	FETCH_OP_UDEREF,	/* User-space Dereference: .offset */
+	// Stage 3 (store) ops
+	FETCH_OP_ST_RAW,	/* Raw: .size */
+	FETCH_OP_ST_MEM,	/* Mem: .offset, .size */
+	FETCH_OP_ST_UMEM,	/* Mem: .offset, .size */
+	FETCH_OP_ST_STRING,	/* String: .offset, .size */
+	FETCH_OP_ST_USTRING,	/* User String: .offset, .size */
+	FETCH_OP_ST_SYMSTR,	/* Kernel Symbol String: .offset, .size */
+	// Stage 4 (modify) op
+	FETCH_OP_MOD_BF,	/* Bitfield: .basesize, .lshift, .rshift */
+	// Stage 5 (loop) op
+	FETCH_OP_LP_ARRAY,	/* Array: .param = loop count */
+	FETCH_OP_TP_ARG,	/* Trace Point argument */
+	FETCH_OP_END,
+	FETCH_NOP_SYMBOL,	/* Unresolved Symbol holder */
+};
+
+struct fetch_insn {
+	enum fetch_op op;
+	union {
+		unsigned int param;
+		struct {
+			unsigned int size;
+			int offset;
+		};
+		struct {
+			unsigned char basesize;
+			unsigned char lshift;
+			unsigned char rshift;
+		};
+		unsigned long immediate;
+		void *data;
+	};
+};
+
+/* fetch + deref*N + store + mod + end <= 16, this allows N=12, enough */
+#define FETCH_INSN_MAX	16
+#define FETCH_TOKEN_COMM	(-ECOMM)
+
+/* Fetch type information table */
+struct fetch_type {
+	const char		*name;		/* Name of type */
+	size_t			size;		/* Byte size of type */
+	bool			is_signed;	/* Signed flag */
+	bool			is_string;	/* String flag */
+	print_type_func_t	print;		/* Print functions */
+	const char		*fmt;		/* Format string */
+	const char		*fmttype;	/* Name in format file */
+};
+
+/* For defining macros, define string/string_size types */
+typedef u32 string;
+typedef u32 string_size;
+
+#define PRINT_TYPE_FUNC_NAME(type)	print_type_##type
+#define PRINT_TYPE_FMT_NAME(type)	print_type_format_##type
+
+/* Printing  in basic type function template */
+#define DECLARE_BASIC_PRINT_TYPE_FUNC(type)				\
+int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, void *data, void *ent);\
+extern const char PRINT_TYPE_FMT_NAME(type)[]
+
+DECLARE_BASIC_PRINT_TYPE_FUNC(u8);
+DECLARE_BASIC_PRINT_TYPE_FUNC(u16);
+DECLARE_BASIC_PRINT_TYPE_FUNC(u32);
+DECLARE_BASIC_PRINT_TYPE_FUNC(u64);
+DECLARE_BASIC_PRINT_TYPE_FUNC(s8);
+DECLARE_BASIC_PRINT_TYPE_FUNC(s16);
+DECLARE_BASIC_PRINT_TYPE_FUNC(s32);
+DECLARE_BASIC_PRINT_TYPE_FUNC(s64);
+DECLARE_BASIC_PRINT_TYPE_FUNC(x8);
+DECLARE_BASIC_PRINT_TYPE_FUNC(x16);
+DECLARE_BASIC_PRINT_TYPE_FUNC(x32);
+DECLARE_BASIC_PRINT_TYPE_FUNC(x64);
+
+DECLARE_BASIC_PRINT_TYPE_FUNC(string);
+DECLARE_BASIC_PRINT_TYPE_FUNC(symbol);
+
+/* Default (unsigned long) fetch type */
+#define __DEFAULT_FETCH_TYPE(t) x##t
+#define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
+#define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
+#define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
+
+#define __ADDR_FETCH_TYPE(t) u##t
+#define _ADDR_FETCH_TYPE(t) __ADDR_FETCH_TYPE(t)
+#define ADDR_FETCH_TYPE _ADDR_FETCH_TYPE(BITS_PER_LONG)
+
+#define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, str, _fmttype)	\
+	{.name = _name,					\
+	 .size = _size,					\
+	 .is_signed = (bool)sign,			\
+	 .is_string = (bool)str,			\
+	 .print = PRINT_TYPE_FUNC_NAME(ptype),		\
+	 .fmt = PRINT_TYPE_FMT_NAME(ptype),		\
+	 .fmttype = _fmttype,				\
+	}
+
+/* Non string types can use these macros */
+#define _ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype)	\
+	__ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, 0, #_fmttype)
+#define ASSIGN_FETCH_TYPE(ptype, ftype, sign)			\
+	_ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, ptype)
+
+/* If ptype is an alias of atype, use this macro (show atype in format) */
+#define ASSIGN_FETCH_TYPE_ALIAS(ptype, atype, ftype, sign)		\
+	_ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, atype)
+
+#define ASSIGN_FETCH_TYPE_END {}
+#define MAX_ARRAY_LEN	64
+
+#ifdef CONFIG_KPROBE_EVENTS
+bool trace_kprobe_on_func_entry(struct trace_event_call *call);
+bool trace_kprobe_error_injectable(struct trace_event_call *call);
+#else
+static inline bool trace_kprobe_on_func_entry(struct trace_event_call *call)
+{
+	return false;
+}
+
+static inline bool trace_kprobe_error_injectable(struct trace_event_call *call)
+{
+	return false;
+}
+#endif /* CONFIG_KPROBE_EVENTS */
+
+struct probe_arg {
+	struct fetch_insn	*code;
+	bool			dynamic;/* Dynamic array (string) is used */
+	unsigned int		offset;	/* Offset from argument entry */
+	unsigned int		count;	/* Array count */
+	const char		*name;	/* Name of this argument */
+	const char		*comm;	/* Command of this argument */
+	char			*fmt;	/* Format string if needed */
+	const struct fetch_type	*type;	/* Type of this argument */
+};
+
+struct trace_uprobe_filter {
+	rwlock_t		rwlock;
+	int			nr_systemwide;
+	struct list_head	perf_events;
+};
+
+/* Event call and class holder */
+struct trace_probe_event {
+	unsigned int			flags;	/* For TP_FLAG_* */
+	struct trace_event_class	class;
+	struct trace_event_call		call;
+	struct list_head 		files;
+	struct list_head		probes;
+	struct trace_uprobe_filter	filter[];
+};
+
+struct trace_probe {
+	struct list_head		list;
+	struct trace_probe_event	*event;
+	ssize_t				size;	/* trace entry size */
+	unsigned int			nr_args;
+	struct probe_arg		args[];
+};
+
+struct event_file_link {
+	struct trace_event_file		*file;
+	struct list_head		list;
+};
+
+static inline bool trace_probe_test_flag(struct trace_probe *tp,
+					 unsigned int flag)
+{
+	return !!(tp->event->flags & flag);
+}
+
+static inline void trace_probe_set_flag(struct trace_probe *tp,
+					unsigned int flag)
+{
+	tp->event->flags |= flag;
+}
+
+static inline void trace_probe_clear_flag(struct trace_probe *tp,
+					  unsigned int flag)
+{
+	tp->event->flags &= ~flag;
+}
+
+static inline bool trace_probe_is_enabled(struct trace_probe *tp)
+{
+	return trace_probe_test_flag(tp, TP_FLAG_TRACE | TP_FLAG_PROFILE);
+}
+
+static inline const char *trace_probe_name(struct trace_probe *tp)
+{
+	return trace_event_name(&tp->event->call);
+}
+
+static inline const char *trace_probe_group_name(struct trace_probe *tp)
+{
+	return tp->event->call.class->system;
+}
+
+static inline struct trace_event_call *
+	trace_probe_event_call(struct trace_probe *tp)
+{
+	return &tp->event->call;
+}
+
+static inline struct trace_probe_event *
+trace_probe_event_from_call(struct trace_event_call *event_call)
+{
+	return container_of(event_call, struct trace_probe_event, call);
+}
+
+static inline struct trace_probe *
+trace_probe_primary_from_call(struct trace_event_call *call)
+{
+	struct trace_probe_event *tpe = trace_probe_event_from_call(call);
+
+	return list_first_entry_or_null(&tpe->probes, struct trace_probe, list);
+}
+
+static inline struct list_head *trace_probe_probe_list(struct trace_probe *tp)
+{
+	return &tp->event->probes;
+}
+
+static inline bool trace_probe_has_sibling(struct trace_probe *tp)
+{
+	struct list_head *list = trace_probe_probe_list(tp);
+
+	return !list_empty(list) && !list_is_singular(list);
+}
+
+static inline int trace_probe_unregister_event_call(struct trace_probe *tp)
+{
+	/* tp->event is unregistered in trace_remove_event_call() */
+	return trace_remove_event_call(&tp->event->call);
+}
+
+static inline bool trace_probe_has_single_file(struct trace_probe *tp)
+{
+	return !!list_is_singular(&tp->event->files);
+}
+
+int trace_probe_init(struct trace_probe *tp, const char *event,
+		     const char *group, bool alloc_filter);
+void trace_probe_cleanup(struct trace_probe *tp);
+int trace_probe_append(struct trace_probe *tp, struct trace_probe *to);
+void trace_probe_unlink(struct trace_probe *tp);
+int trace_probe_register_event_call(struct trace_probe *tp);
+int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file);
+int trace_probe_remove_file(struct trace_probe *tp,
+			    struct trace_event_file *file);
+struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
+						struct trace_event_file *file);
+int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b);
+bool trace_probe_match_command_args(struct trace_probe *tp,
+				    int argc, const char **argv);
+int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **));
+
+#define trace_probe_for_each_link(pos, tp)	\
+	list_for_each_entry(pos, &(tp)->event->files, list)
+#define trace_probe_for_each_link_rcu(pos, tp)	\
+	list_for_each_entry_rcu(pos, &(tp)->event->files, list)
+
+#define TPARG_FL_RETURN BIT(0)
+#define TPARG_FL_KERNEL BIT(1)
+#define TPARG_FL_FENTRY BIT(2)
+#define TPARG_FL_TPOINT BIT(3)
+#define TPARG_FL_MASK	GENMASK(3, 0)
+
+extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i,
+				const char *argv, unsigned int flags);
+
+extern int traceprobe_update_arg(struct probe_arg *arg);
+extern void traceprobe_free_probe_arg(struct probe_arg *arg);
+
+extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
+int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
+				char *buf, int offset);
+
+enum probe_print_type {
+	PROBE_PRINT_NORMAL,
+	PROBE_PRINT_RETURN,
+	PROBE_PRINT_EVENT,
+};
+
+extern int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype);
+
+#ifdef CONFIG_PERF_EVENTS
+extern struct trace_event_call *
+create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
+			  bool is_return);
+extern void destroy_local_trace_kprobe(struct trace_event_call *event_call);
+
+extern struct trace_event_call *
+create_local_trace_uprobe(char *name, unsigned long offs,
+			  unsigned long ref_ctr_offset, bool is_return);
+extern void destroy_local_trace_uprobe(struct trace_event_call *event_call);
+#endif
+extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
+					size_t offset, struct trace_probe *tp);
+
+#undef ERRORS
+#define ERRORS	\
+	C(FILE_NOT_FOUND,	"Failed to find the given file"),	\
+	C(NO_REGULAR_FILE,	"Not a regular file"),			\
+	C(BAD_REFCNT,		"Invalid reference counter offset"),	\
+	C(REFCNT_OPEN_BRACE,	"Reference counter brace is not closed"), \
+	C(BAD_REFCNT_SUFFIX,	"Reference counter has wrong suffix"),	\
+	C(BAD_UPROBE_OFFS,	"Invalid uprobe offset"),		\
+	C(MAXACT_NO_KPROBE,	"Maxactive is not for kprobe"),		\
+	C(BAD_MAXACT,		"Invalid maxactive number"),		\
+	C(MAXACT_TOO_BIG,	"Maxactive is too big"),		\
+	C(BAD_PROBE_ADDR,	"Invalid probed address or symbol"),	\
+	C(NON_UNIQ_SYMBOL,	"The symbol is not unique"),		\
+	C(BAD_RETPROBE,		"Retprobe address must be an function entry"), \
+	C(BAD_ADDR_SUFFIX,	"Invalid probed address suffix"), \
+	C(NO_GROUP_NAME,	"Group name is not specified"),		\
+	C(GROUP_TOO_LONG,	"Group name is too long"),		\
+	C(BAD_GROUP_NAME,	"Group name must follow the same rules as C identifiers"), \
+	C(NO_EVENT_NAME,	"Event name is not specified"),		\
+	C(EVENT_TOO_LONG,	"Event name is too long"),		\
+	C(BAD_EVENT_NAME,	"Event name must follow the same rules as C identifiers"), \
+	C(EVENT_EXIST,		"Given group/event name is already used by another event"), \
+	C(RETVAL_ON_PROBE,	"$retval is not available on probe"),	\
+	C(BAD_STACK_NUM,	"Invalid stack number"),		\
+	C(BAD_ARG_NUM,		"Invalid argument number"),		\
+	C(BAD_VAR,		"Invalid $-valiable specified"),	\
+	C(BAD_REG_NAME,		"Invalid register name"),		\
+	C(BAD_MEM_ADDR,		"Invalid memory address"),		\
+	C(BAD_IMM,		"Invalid immediate value"),		\
+	C(IMMSTR_NO_CLOSE,	"String is not closed with '\"'"),	\
+	C(FILE_ON_KPROBE,	"File offset is not available with kprobe"), \
+	C(BAD_FILE_OFFS,	"Invalid file offset value"),		\
+	C(SYM_ON_UPROBE,	"Symbol is not available with uprobe"),	\
+	C(TOO_MANY_OPS,		"Dereference is too much nested"), 	\
+	C(DEREF_NEED_BRACE,	"Dereference needs a brace"),		\
+	C(BAD_DEREF_OFFS,	"Invalid dereference offset"),		\
+	C(DEREF_OPEN_BRACE,	"Dereference brace is not closed"),	\
+	C(COMM_CANT_DEREF,	"$comm can not be dereferenced"),	\
+	C(BAD_FETCH_ARG,	"Invalid fetch argument"),		\
+	C(ARRAY_NO_CLOSE,	"Array is not closed"),			\
+	C(BAD_ARRAY_SUFFIX,	"Array has wrong suffix"),		\
+	C(BAD_ARRAY_NUM,	"Invalid array size"),			\
+	C(ARRAY_TOO_BIG,	"Array number is too big"),		\
+	C(BAD_TYPE,		"Unknown type is specified"),		\
+	C(BAD_STRING,		"String accepts only memory argument"),	\
+	C(BAD_SYMSTRING,	"Symbol String doesn't accept data/userdata"),	\
+	C(BAD_BITFIELD,		"Invalid bitfield"),			\
+	C(ARG_NAME_TOO_LONG,	"Argument name is too long"),		\
+	C(NO_ARG_NAME,		"Argument name is not specified"),	\
+	C(BAD_ARG_NAME,		"Argument name must follow the same rules as C identifiers"), \
+	C(USED_ARG_NAME,	"This argument name is already used"),	\
+	C(ARG_TOO_LONG,		"Argument expression is too long"),	\
+	C(NO_ARG_BODY,		"No argument expression"),		\
+	C(BAD_INSN_BNDRY,	"Probe point is not an instruction boundary"),\
+	C(FAIL_REG_PROBE,	"Failed to register probe event"),\
+	C(DIFF_PROBE_TYPE,	"Probe type is different from existing probe"),\
+	C(DIFF_ARG_TYPE,	"Argument type or name is different from existing probe"),\
+	C(SAME_PROBE,		"There is already the exact same probe event"),\
+	C(NO_EVENT_INFO,	"This requires both group and event name to attach"),\
+	C(BAD_ATTACH_EVENT,	"Attached event does not exist"),\
+	C(BAD_ATTACH_ARG,	"Attached event does not have this field"),\
+	C(NO_EP_FILTER,		"No filter rule after 'if'"),
+
+#undef C
+#define C(a, b)		TP_ERR_##a
+
+/* Define TP_ERR_ */
+enum { ERRORS };
+
+/* Error text is defined in trace_probe.c */
+
+struct trace_probe_log {
+	const char	*subsystem;
+	const char	**argv;
+	int		argc;
+	int		index;
+};
+
+void trace_probe_log_init(const char *subsystem, int argc, const char **argv);
+void trace_probe_log_set_index(int index);
+void trace_probe_log_clear(void);
+void __trace_probe_log_err(int offset, int err);
+
+#define trace_probe_log_err(offs, err)	\
+	__trace_probe_log_err(offs, TP_ERR_##err)
diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h
new file mode 100644
index 000000000..2da70be83
--- /dev/null
+++ b/kernel/trace/trace_probe_kernel.h
@@ -0,0 +1,101 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __TRACE_PROBE_KERNEL_H_
+#define __TRACE_PROBE_KERNEL_H_
+
+/*
+ * This depends on trace_probe.h, but can not include it due to
+ * the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c.
+ * Which means that any other user must include trace_probe.h before including
+ * this file.
+ */
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline int
+kern_fetch_store_strlen_user(unsigned long addr)
+{
+	const void __user *uaddr =  (__force const void __user *)addr;
+
+	return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
+}
+
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline int
+kern_fetch_store_strlen(unsigned long addr)
+{
+	int ret, len = 0;
+	u8 c;
+
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+	if (addr < TASK_SIZE)
+		return kern_fetch_store_strlen_user(addr);
+#endif
+
+	do {
+		ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);
+		len++;
+	} while (c && ret == 0 && len < MAX_STRING_SIZE);
+
+	return (ret < 0) ? ret : len;
+}
+
+static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base)
+{
+	if (ret < 0)
+		ret = 0;
+	*(u32 *)dest = make_data_loc(ret, __dest - base);
+}
+
+/*
+ * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
+ * with max length and relative data location.
+ */
+static nokprobe_inline int
+kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)
+{
+	const void __user *uaddr =  (__force const void __user *)addr;
+	int maxlen = get_loc_len(*(u32 *)dest);
+	void *__dest;
+	long ret;
+
+	if (unlikely(!maxlen))
+		return -ENOMEM;
+
+	__dest = get_loc_data(dest, base);
+
+	ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
+	set_data_loc(ret, dest, __dest, base);
+
+	return ret;
+}
+
+/*
+ * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
+ * length and relative data location.
+ */
+static nokprobe_inline int
+kern_fetch_store_string(unsigned long addr, void *dest, void *base)
+{
+	int maxlen = get_loc_len(*(u32 *)dest);
+	void *__dest;
+	long ret;
+
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+	if ((unsigned long)addr < TASK_SIZE)
+		return kern_fetch_store_string_user(addr, dest, base);
+#endif
+
+	if (unlikely(!maxlen))
+		return -ENOMEM;
+
+	__dest = get_loc_data(dest, base);
+
+	/*
+	 * Try to get string again, since the string can be changed while
+	 * probing.
+	 */
+	ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
+	set_data_loc(ret, dest, __dest, base);
+
+	return ret;
+}
+
+#endif /* __TRACE_PROBE_KERNEL_H_ */
diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h
new file mode 100644
index 000000000..3e2f5a43b
--- /dev/null
+++ b/kernel/trace/trace_probe_tmpl.h
@@ -0,0 +1,283 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Traceprobe fetch helper inlines
+ */
+
+static nokprobe_inline void
+fetch_store_raw(unsigned long val, struct fetch_insn *code, void *buf)
+{
+	switch (code->size) {
+	case 1:
+		*(u8 *)buf = (u8)val;
+		break;
+	case 2:
+		*(u16 *)buf = (u16)val;
+		break;
+	case 4:
+		*(u32 *)buf = (u32)val;
+		break;
+	case 8:
+		//TBD: 32bit signed
+		*(u64 *)buf = (u64)val;
+		break;
+	default:
+		*(unsigned long *)buf = val;
+	}
+}
+
+static nokprobe_inline void
+fetch_apply_bitfield(struct fetch_insn *code, void *buf)
+{
+	switch (code->basesize) {
+	case 1:
+		*(u8 *)buf <<= code->lshift;
+		*(u8 *)buf >>= code->rshift;
+		break;
+	case 2:
+		*(u16 *)buf <<= code->lshift;
+		*(u16 *)buf >>= code->rshift;
+		break;
+	case 4:
+		*(u32 *)buf <<= code->lshift;
+		*(u32 *)buf >>= code->rshift;
+		break;
+	case 8:
+		*(u64 *)buf <<= code->lshift;
+		*(u64 *)buf >>= code->rshift;
+		break;
+	}
+}
+
+/*
+ * These functions must be defined for each callsite.
+ * Return consumed dynamic data size (>= 0), or error (< 0).
+ * If dest is NULL, don't store result and return required dynamic data size.
+ */
+static int
+process_fetch_insn(struct fetch_insn *code, void *rec,
+		   void *dest, void *base);
+static nokprobe_inline int fetch_store_strlen(unsigned long addr);
+static nokprobe_inline int
+fetch_store_string(unsigned long addr, void *dest, void *base);
+static nokprobe_inline int fetch_store_strlen_user(unsigned long addr);
+static nokprobe_inline int
+fetch_store_string_user(unsigned long addr, void *dest, void *base);
+static nokprobe_inline int
+probe_mem_read(void *dest, void *src, size_t size);
+static nokprobe_inline int
+probe_mem_read_user(void *dest, void *src, size_t size);
+
+static nokprobe_inline int
+fetch_store_symstrlen(unsigned long addr)
+{
+	char namebuf[KSYM_SYMBOL_LEN];
+	int ret;
+
+	ret = sprint_symbol(namebuf, addr);
+	if (ret < 0)
+		return 0;
+
+	return ret + 1;
+}
+
+/*
+ * Fetch a null-terminated symbol string + offset. Caller MUST set *(u32 *)buf
+ * with max length and relative data location.
+ */
+static nokprobe_inline int
+fetch_store_symstring(unsigned long addr, void *dest, void *base)
+{
+	int maxlen = get_loc_len(*(u32 *)dest);
+	void *__dest;
+
+	if (unlikely(!maxlen))
+		return -ENOMEM;
+
+	__dest = get_loc_data(dest, base);
+
+	return sprint_symbol(__dest, addr);
+}
+
+/* From the 2nd stage, routine is same */
+static nokprobe_inline int
+process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
+			   void *dest, void *base)
+{
+	struct fetch_insn *s3 = NULL;
+	int total = 0, ret = 0, i = 0;
+	u32 loc = 0;
+	unsigned long lval = val;
+
+stage2:
+	/* 2nd stage: dereference memory if needed */
+	do {
+		if (code->op == FETCH_OP_DEREF) {
+			lval = val;
+			ret = probe_mem_read(&val, (void *)val + code->offset,
+					     sizeof(val));
+		} else if (code->op == FETCH_OP_UDEREF) {
+			lval = val;
+			ret = probe_mem_read_user(&val,
+				 (void *)val + code->offset, sizeof(val));
+		} else
+			break;
+		if (ret)
+			return ret;
+		code++;
+	} while (1);
+
+	s3 = code;
+stage3:
+	/* 3rd stage: store value to buffer */
+	if (unlikely(!dest)) {
+		switch (code->op) {
+		case FETCH_OP_ST_STRING:
+			ret = fetch_store_strlen(val + code->offset);
+			code++;
+			goto array;
+		case FETCH_OP_ST_USTRING:
+			ret = fetch_store_strlen_user(val + code->offset);
+			code++;
+			goto array;
+		case FETCH_OP_ST_SYMSTR:
+			ret = fetch_store_symstrlen(val + code->offset);
+			code++;
+			goto array;
+		default:
+			return -EILSEQ;
+		}
+	}
+
+	switch (code->op) {
+	case FETCH_OP_ST_RAW:
+		fetch_store_raw(val, code, dest);
+		break;
+	case FETCH_OP_ST_MEM:
+		probe_mem_read(dest, (void *)val + code->offset, code->size);
+		break;
+	case FETCH_OP_ST_UMEM:
+		probe_mem_read_user(dest, (void *)val + code->offset, code->size);
+		break;
+	case FETCH_OP_ST_STRING:
+		loc = *(u32 *)dest;
+		ret = fetch_store_string(val + code->offset, dest, base);
+		break;
+	case FETCH_OP_ST_USTRING:
+		loc = *(u32 *)dest;
+		ret = fetch_store_string_user(val + code->offset, dest, base);
+		break;
+	case FETCH_OP_ST_SYMSTR:
+		loc = *(u32 *)dest;
+		ret = fetch_store_symstring(val + code->offset, dest, base);
+		break;
+	default:
+		return -EILSEQ;
+	}
+	code++;
+
+	/* 4th stage: modify stored value if needed */
+	if (code->op == FETCH_OP_MOD_BF) {
+		fetch_apply_bitfield(code, dest);
+		code++;
+	}
+
+array:
+	/* the last stage: Loop on array */
+	if (code->op == FETCH_OP_LP_ARRAY) {
+		if (ret < 0)
+			ret = 0;
+		total += ret;
+		if (++i < code->param) {
+			code = s3;
+			if (s3->op != FETCH_OP_ST_STRING &&
+			    s3->op != FETCH_OP_ST_USTRING) {
+				dest += s3->size;
+				val += s3->size;
+				goto stage3;
+			}
+			code--;
+			val = lval + sizeof(char *);
+			if (dest) {
+				dest += sizeof(u32);
+				*(u32 *)dest = update_data_loc(loc, ret);
+			}
+			goto stage2;
+		}
+		code++;
+		ret = total;
+	}
+
+	return code->op == FETCH_OP_END ? ret : -EILSEQ;
+}
+
+/* Sum up total data length for dynamic arrays (strings) */
+static nokprobe_inline int
+__get_data_size(struct trace_probe *tp, struct pt_regs *regs)
+{
+	struct probe_arg *arg;
+	int i, len, ret = 0;
+
+	for (i = 0; i < tp->nr_args; i++) {
+		arg = tp->args + i;
+		if (unlikely(arg->dynamic)) {
+			len = process_fetch_insn(arg->code, regs, NULL, NULL);
+			if (len > 0)
+				ret += len;
+		}
+	}
+
+	return ret;
+}
+
+/* Store the value of each argument */
+static nokprobe_inline void
+store_trace_args(void *data, struct trace_probe *tp, void *rec,
+		 int header_size, int maxlen)
+{
+	struct probe_arg *arg;
+	void *base = data - header_size;
+	void *dyndata = data + tp->size;
+	u32 *dl;	/* Data location */
+	int ret, i;
+
+	for (i = 0; i < tp->nr_args; i++) {
+		arg = tp->args + i;
+		dl = data + arg->offset;
+		/* Point the dynamic data area if needed */
+		if (unlikely(arg->dynamic))
+			*dl = make_data_loc(maxlen, dyndata - base);
+		ret = process_fetch_insn(arg->code, rec, dl, base);
+		if (arg->dynamic && likely(ret > 0)) {
+			dyndata += ret;
+			maxlen -= ret;
+		}
+	}
+}
+
+static inline int
+print_probe_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
+		 u8 *data, void *field)
+{
+	void *p;
+	int i, j;
+
+	for (i = 0; i < nr_args; i++) {
+		struct probe_arg *a = args + i;
+
+		trace_seq_printf(s, " %s=", a->name);
+		if (likely(!a->count)) {
+			if (!a->type->print(s, data + a->offset, field))
+				return -ENOMEM;
+			continue;
+		}
+		trace_seq_putc(s, '{');
+		p = data + a->offset;
+		for (j = 0; j < a->count; j++) {
+			if (!a->type->print(s, p, field))
+				return -ENOMEM;
+			trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
+			p += a->type->size;
+		}
+	}
+	return 0;
+}
diff --git a/kernel/trace/trace_recursion_record.c b/kernel/trace/trace_recursion_record.c
new file mode 100644
index 000000000..a520b11af
--- /dev/null
+++ b/kernel/trace/trace_recursion_record.c
@@ -0,0 +1,233 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/seq_file.h>
+#include <linux/kallsyms.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+#include <linux/fs.h>
+
+#include "trace_output.h"
+
+struct recursed_functions {
+	unsigned long		ip;
+	unsigned long		parent_ip;
+};
+
+static struct recursed_functions recursed_functions[CONFIG_FTRACE_RECORD_RECURSION_SIZE];
+static atomic_t nr_records;
+
+/*
+ * Cache the last found function. Yes, updates to this is racey, but
+ * so is memory cache ;-)
+ */
+static unsigned long cached_function;
+
+void ftrace_record_recursion(unsigned long ip, unsigned long parent_ip)
+{
+	int index = 0;
+	int i;
+	unsigned long old;
+
+ again:
+	/* First check the last one recorded */
+	if (ip == cached_function)
+		return;
+
+	i = atomic_read(&nr_records);
+	/* nr_records is -1 when clearing records */
+	smp_mb__after_atomic();
+	if (i < 0)
+		return;
+
+	/*
+	 * If there's two writers and this writer comes in second,
+	 * the cmpxchg() below to update the ip will fail. Then this
+	 * writer will try again. It is possible that index will now
+	 * be greater than nr_records. This is because the writer
+	 * that succeeded has not updated the nr_records yet.
+	 * This writer could keep trying again until the other writer
+	 * updates nr_records. But if the other writer takes an
+	 * interrupt, and that interrupt locks up that CPU, we do
+	 * not want this CPU to lock up due to the recursion protection,
+	 * and have a bug report showing this CPU as the cause of
+	 * locking up the computer. To not lose this record, this
+	 * writer will simply use the next position to update the
+	 * recursed_functions, and it will update the nr_records
+	 * accordingly.
+	 */
+	if (index < i)
+		index = i;
+	if (index >= CONFIG_FTRACE_RECORD_RECURSION_SIZE)
+		return;
+
+	for (i = index - 1; i >= 0; i--) {
+		if (recursed_functions[i].ip == ip) {
+			cached_function = ip;
+			return;
+		}
+	}
+
+	cached_function = ip;
+
+	/*
+	 * We only want to add a function if it hasn't been added before.
+	 * Add to the current location before incrementing the count.
+	 * If it fails to add, then increment the index (save in i)
+	 * and try again.
+	 */
+	old = cmpxchg(&recursed_functions[index].ip, 0, ip);
+	if (old != 0) {
+		/* Did something else already added this for us? */
+		if (old == ip)
+			return;
+		/* Try the next location (use i for the next index) */
+		index++;
+		goto again;
+	}
+
+	recursed_functions[index].parent_ip = parent_ip;
+
+	/*
+	 * It's still possible that we could race with the clearing
+	 *    CPU0                                    CPU1
+	 *    ----                                    ----
+	 *                                       ip = func
+	 *  nr_records = -1;
+	 *  recursed_functions[0] = 0;
+	 *                                       i = -1
+	 *                                       if (i < 0)
+	 *  nr_records = 0;
+	 *  (new recursion detected)
+	 *      recursed_functions[0] = func
+	 *                                            cmpxchg(recursed_functions[0],
+	 *                                                    func, 0)
+	 *
+	 * But the worse that could happen is that we get a zero in
+	 * the recursed_functions array, and it's likely that "func" will
+	 * be recorded again.
+	 */
+	i = atomic_read(&nr_records);
+	smp_mb__after_atomic();
+	if (i < 0)
+		cmpxchg(&recursed_functions[index].ip, ip, 0);
+	else if (i <= index)
+		atomic_cmpxchg(&nr_records, i, index + 1);
+}
+EXPORT_SYMBOL_GPL(ftrace_record_recursion);
+
+static DEFINE_MUTEX(recursed_function_lock);
+static struct trace_seq *tseq;
+
+static void *recursed_function_seq_start(struct seq_file *m, loff_t *pos)
+{
+	void *ret = NULL;
+	int index;
+
+	mutex_lock(&recursed_function_lock);
+	index = atomic_read(&nr_records);
+	if (*pos < index) {
+		ret = &recursed_functions[*pos];
+	}
+
+	tseq = kzalloc(sizeof(*tseq), GFP_KERNEL);
+	if (!tseq)
+		return ERR_PTR(-ENOMEM);
+
+	trace_seq_init(tseq);
+
+	return ret;
+}
+
+static void *recursed_function_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	int index;
+	int p;
+
+	index = atomic_read(&nr_records);
+	p = ++(*pos);
+
+	return p < index ? &recursed_functions[p] : NULL;
+}
+
+static void recursed_function_seq_stop(struct seq_file *m, void *v)
+{
+	kfree(tseq);
+	mutex_unlock(&recursed_function_lock);
+}
+
+static int recursed_function_seq_show(struct seq_file *m, void *v)
+{
+	struct recursed_functions *record = v;
+	int ret = 0;
+
+	if (record) {
+		trace_seq_print_sym(tseq, record->parent_ip, true);
+		trace_seq_puts(tseq, ":\t");
+		trace_seq_print_sym(tseq, record->ip, true);
+		trace_seq_putc(tseq, '\n');
+		ret = trace_print_seq(m, tseq);
+	}
+
+	return ret;
+}
+
+static const struct seq_operations recursed_function_seq_ops = {
+	.start  = recursed_function_seq_start,
+	.next   = recursed_function_seq_next,
+	.stop   = recursed_function_seq_stop,
+	.show   = recursed_function_seq_show
+};
+
+static int recursed_function_open(struct inode *inode, struct file *file)
+{
+	int ret = 0;
+
+	mutex_lock(&recursed_function_lock);
+	/* If this file was opened for write, then erase contents */
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+		/* disable updating records */
+		atomic_set(&nr_records, -1);
+		smp_mb__after_atomic();
+		memset(recursed_functions, 0, sizeof(recursed_functions));
+		smp_wmb();
+		/* enable them again */
+		atomic_set(&nr_records, 0);
+	}
+	if (file->f_mode & FMODE_READ)
+		ret = seq_open(file, &recursed_function_seq_ops);
+	mutex_unlock(&recursed_function_lock);
+
+	return ret;
+}
+
+static ssize_t recursed_function_write(struct file *file,
+				       const char __user *buffer,
+				       size_t count, loff_t *ppos)
+{
+	return count;
+}
+
+static int recursed_function_release(struct inode *inode, struct file *file)
+{
+	if (file->f_mode & FMODE_READ)
+		seq_release(inode, file);
+	return 0;
+}
+
+static const struct file_operations recursed_functions_fops = {
+	.open           = recursed_function_open,
+	.write		= recursed_function_write,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release        = recursed_function_release,
+};
+
+__init static int create_recursed_functions(void)
+{
+
+	trace_create_file("recursed_functions", TRACE_MODE_WRITE,
+			  NULL, NULL, &recursed_functions_fops);
+	return 0;
+}
+
+fs_initcall(create_recursed_functions);
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
new file mode 100644
index 000000000..c9ffdcfe6
--- /dev/null
+++ b/kernel/trace/trace_sched_switch.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace context switch
+ *
+ * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
+ *
+ */
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+#include <trace/events/sched.h>
+
+#include "trace.h"
+
+#define RECORD_CMDLINE	1
+#define RECORD_TGID	2
+
+static int		sched_cmdline_ref;
+static int		sched_tgid_ref;
+static DEFINE_MUTEX(sched_register_mutex);
+
+static void
+probe_sched_switch(void *ignore, bool preempt,
+		   struct task_struct *prev, struct task_struct *next,
+		   unsigned int prev_state)
+{
+	int flags;
+
+	flags = (RECORD_TGID * !!sched_tgid_ref) +
+		(RECORD_CMDLINE * !!sched_cmdline_ref);
+
+	if (!flags)
+		return;
+	tracing_record_taskinfo_sched_switch(prev, next, flags);
+}
+
+static void
+probe_sched_wakeup(void *ignore, struct task_struct *wakee)
+{
+	int flags;
+
+	flags = (RECORD_TGID * !!sched_tgid_ref) +
+		(RECORD_CMDLINE * !!sched_cmdline_ref);
+
+	if (!flags)
+		return;
+	tracing_record_taskinfo_sched_switch(current, wakee, flags);
+}
+
+static int tracing_sched_register(void)
+{
+	int ret;
+
+	ret = register_trace_sched_wakeup(probe_sched_wakeup, NULL);
+	if (ret) {
+		pr_info("wakeup trace: Couldn't activate tracepoint"
+			" probe to kernel_sched_wakeup\n");
+		return ret;
+	}
+
+	ret = register_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
+	if (ret) {
+		pr_info("wakeup trace: Couldn't activate tracepoint"
+			" probe to kernel_sched_wakeup_new\n");
+		goto fail_deprobe;
+	}
+
+	ret = register_trace_sched_switch(probe_sched_switch, NULL);
+	if (ret) {
+		pr_info("sched trace: Couldn't activate tracepoint"
+			" probe to kernel_sched_switch\n");
+		goto fail_deprobe_wake_new;
+	}
+
+	return ret;
+fail_deprobe_wake_new:
+	unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
+fail_deprobe:
+	unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
+	return ret;
+}
+
+static void tracing_sched_unregister(void)
+{
+	unregister_trace_sched_switch(probe_sched_switch, NULL);
+	unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
+	unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
+}
+
+static void tracing_start_sched_switch(int ops)
+{
+	bool sched_register;
+
+	mutex_lock(&sched_register_mutex);
+	sched_register = (!sched_cmdline_ref && !sched_tgid_ref);
+
+	switch (ops) {
+	case RECORD_CMDLINE:
+		sched_cmdline_ref++;
+		break;
+
+	case RECORD_TGID:
+		sched_tgid_ref++;
+		break;
+	}
+
+	if (sched_register && (sched_cmdline_ref || sched_tgid_ref))
+		tracing_sched_register();
+	mutex_unlock(&sched_register_mutex);
+}
+
+static void tracing_stop_sched_switch(int ops)
+{
+	mutex_lock(&sched_register_mutex);
+
+	switch (ops) {
+	case RECORD_CMDLINE:
+		sched_cmdline_ref--;
+		break;
+
+	case RECORD_TGID:
+		sched_tgid_ref--;
+		break;
+	}
+
+	if (!sched_cmdline_ref && !sched_tgid_ref)
+		tracing_sched_unregister();
+	mutex_unlock(&sched_register_mutex);
+}
+
+void tracing_start_cmdline_record(void)
+{
+	tracing_start_sched_switch(RECORD_CMDLINE);
+}
+
+void tracing_stop_cmdline_record(void)
+{
+	tracing_stop_sched_switch(RECORD_CMDLINE);
+}
+
+void tracing_start_tgid_record(void)
+{
+	tracing_start_sched_switch(RECORD_TGID);
+}
+
+void tracing_stop_tgid_record(void)
+{
+	tracing_stop_sched_switch(RECORD_TGID);
+}
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
new file mode 100644
index 000000000..0469a04a3
--- /dev/null
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -0,0 +1,820 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace task wakeup timings
+ *
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ *
+ * Based on code from the latency_tracer, that is:
+ *
+ *  Copyright (C) 2004-2006 Ingo Molnar
+ *  Copyright (C) 2004 Nadia Yvette Chambers
+ */
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+#include <linux/sched/rt.h>
+#include <linux/sched/deadline.h>
+#include <trace/events/sched.h>
+#include "trace.h"
+
+static struct trace_array	*wakeup_trace;
+static int __read_mostly	tracer_enabled;
+
+static struct task_struct	*wakeup_task;
+static int			wakeup_cpu;
+static int			wakeup_current_cpu;
+static unsigned			wakeup_prio = -1;
+static bool			wakeup_rt;
+static bool			wakeup_dl;
+static bool			tracing_dl;
+
+static arch_spinlock_t wakeup_lock =
+	(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+
+static void wakeup_reset(struct trace_array *tr);
+static void __wakeup_reset(struct trace_array *tr);
+static int start_func_tracer(struct trace_array *tr, int graph);
+static void stop_func_tracer(struct trace_array *tr, int graph);
+
+static int save_flags;
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+# define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
+#else
+# define is_graph(tr) false
+#endif
+
+#ifdef CONFIG_FUNCTION_TRACER
+
+static bool function_enabled;
+
+/*
+ * Prologue for the wakeup function tracers.
+ *
+ * Returns 1 if it is OK to continue, and preemption
+ *            is disabled and data->disabled is incremented.
+ *         0 if the trace is to be ignored, and preemption
+ *            is not disabled and data->disabled is
+ *            kept the same.
+ *
+ * Note, this function is also used outside this ifdef but
+ *  inside the #ifdef of the function graph tracer below.
+ *  This is OK, since the function graph tracer is
+ *  dependent on the function tracer.
+ */
+static int
+func_prolog_preempt_disable(struct trace_array *tr,
+			    struct trace_array_cpu **data,
+			    unsigned int *trace_ctx)
+{
+	long disabled;
+	int cpu;
+
+	if (likely(!wakeup_task))
+		return 0;
+
+	*trace_ctx = tracing_gen_ctx();
+	preempt_disable_notrace();
+
+	cpu = raw_smp_processor_id();
+	if (cpu != wakeup_current_cpu)
+		goto out_enable;
+
+	*data = per_cpu_ptr(tr->array_buffer.data, cpu);
+	disabled = atomic_inc_return(&(*data)->disabled);
+	if (unlikely(disabled != 1))
+		goto out;
+
+	return 1;
+
+out:
+	atomic_dec(&(*data)->disabled);
+
+out_enable:
+	preempt_enable_notrace();
+	return 0;
+}
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+static int wakeup_display_graph(struct trace_array *tr, int set)
+{
+	if (!(is_graph(tr) ^ set))
+		return 0;
+
+	stop_func_tracer(tr, !set);
+
+	wakeup_reset(wakeup_trace);
+	tr->max_latency = 0;
+
+	return start_func_tracer(tr, set);
+}
+
+static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
+{
+	struct trace_array *tr = wakeup_trace;
+	struct trace_array_cpu *data;
+	unsigned int trace_ctx;
+	int ret = 0;
+
+	if (ftrace_graph_ignore_func(trace))
+		return 0;
+	/*
+	 * Do not trace a function if it's filtered by set_graph_notrace.
+	 * Make the index of ret stack negative to indicate that it should
+	 * ignore further functions.  But it needs its own ret stack entry
+	 * to recover the original index in order to continue tracing after
+	 * returning from the function.
+	 */
+	if (ftrace_graph_notrace_addr(trace->func))
+		return 1;
+
+	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
+		return 0;
+
+	ret = __trace_graph_entry(tr, trace, trace_ctx);
+	atomic_dec(&data->disabled);
+	preempt_enable_notrace();
+
+	return ret;
+}
+
+static void wakeup_graph_return(struct ftrace_graph_ret *trace)
+{
+	struct trace_array *tr = wakeup_trace;
+	struct trace_array_cpu *data;
+	unsigned int trace_ctx;
+
+	ftrace_graph_addr_finish(trace);
+
+	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
+		return;
+
+	__trace_graph_return(tr, trace, trace_ctx);
+	atomic_dec(&data->disabled);
+
+	preempt_enable_notrace();
+	return;
+}
+
+static struct fgraph_ops fgraph_wakeup_ops = {
+	.entryfunc = &wakeup_graph_entry,
+	.retfunc = &wakeup_graph_return,
+};
+
+static void wakeup_trace_open(struct trace_iterator *iter)
+{
+	if (is_graph(iter->tr))
+		graph_trace_open(iter);
+	else
+		iter->private = NULL;
+}
+
+static void wakeup_trace_close(struct trace_iterator *iter)
+{
+	if (iter->private)
+		graph_trace_close(iter);
+}
+
+#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
+			    TRACE_GRAPH_PRINT_CPU |  \
+			    TRACE_GRAPH_PRINT_REL_TIME | \
+			    TRACE_GRAPH_PRINT_DURATION | \
+			    TRACE_GRAPH_PRINT_OVERHEAD | \
+			    TRACE_GRAPH_PRINT_IRQS)
+
+static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
+{
+	/*
+	 * In graph mode call the graph tracer output function,
+	 * otherwise go with the TRACE_FN event handler
+	 */
+	if (is_graph(iter->tr))
+		return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
+
+	return TRACE_TYPE_UNHANDLED;
+}
+
+static void wakeup_print_header(struct seq_file *s)
+{
+	if (is_graph(wakeup_trace))
+		print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
+	else
+		trace_default_header(s);
+}
+#endif /* else CONFIG_FUNCTION_GRAPH_TRACER */
+
+/*
+ * wakeup uses its own tracer function to keep the overhead down:
+ */
+static void
+wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
+		   struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	struct trace_array *tr = wakeup_trace;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	unsigned int trace_ctx;
+
+	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
+		return;
+
+	local_irq_save(flags);
+	trace_function(tr, ip, parent_ip, trace_ctx);
+	local_irq_restore(flags);
+
+	atomic_dec(&data->disabled);
+	preempt_enable_notrace();
+}
+
+static int register_wakeup_function(struct trace_array *tr, int graph, int set)
+{
+	int ret;
+
+	/* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
+	if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
+		return 0;
+
+	if (graph)
+		ret = register_ftrace_graph(&fgraph_wakeup_ops);
+	else
+		ret = register_ftrace_function(tr->ops);
+
+	if (!ret)
+		function_enabled = true;
+
+	return ret;
+}
+
+static void unregister_wakeup_function(struct trace_array *tr, int graph)
+{
+	if (!function_enabled)
+		return;
+
+	if (graph)
+		unregister_ftrace_graph(&fgraph_wakeup_ops);
+	else
+		unregister_ftrace_function(tr->ops);
+
+	function_enabled = false;
+}
+
+static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
+{
+	if (!(mask & TRACE_ITER_FUNCTION))
+		return 0;
+
+	if (set)
+		register_wakeup_function(tr, is_graph(tr), 1);
+	else
+		unregister_wakeup_function(tr, is_graph(tr));
+	return 1;
+}
+#else /* CONFIG_FUNCTION_TRACER */
+static int register_wakeup_function(struct trace_array *tr, int graph, int set)
+{
+	return 0;
+}
+static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
+static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
+{
+	return 0;
+}
+#endif /* else CONFIG_FUNCTION_TRACER */
+
+#ifndef CONFIG_FUNCTION_GRAPH_TRACER
+static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
+{
+	return TRACE_TYPE_UNHANDLED;
+}
+
+static void wakeup_trace_open(struct trace_iterator *iter) { }
+static void wakeup_trace_close(struct trace_iterator *iter) { }
+
+static void wakeup_print_header(struct seq_file *s)
+{
+	trace_default_header(s);
+}
+#endif /* !CONFIG_FUNCTION_GRAPH_TRACER */
+
+static void
+__trace_function(struct trace_array *tr,
+		 unsigned long ip, unsigned long parent_ip,
+		 unsigned int trace_ctx)
+{
+	if (is_graph(tr))
+		trace_graph_function(tr, ip, parent_ip, trace_ctx);
+	else
+		trace_function(tr, ip, parent_ip, trace_ctx);
+}
+
+static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set)
+{
+	struct tracer *tracer = tr->current_trace;
+
+	if (wakeup_function_set(tr, mask, set))
+		return 0;
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	if (mask & TRACE_ITER_DISPLAY_GRAPH)
+		return wakeup_display_graph(tr, set);
+#endif
+
+	return trace_keep_overwrite(tracer, mask, set);
+}
+
+static int start_func_tracer(struct trace_array *tr, int graph)
+{
+	int ret;
+
+	ret = register_wakeup_function(tr, graph, 0);
+
+	if (!ret && tracing_is_enabled())
+		tracer_enabled = 1;
+	else
+		tracer_enabled = 0;
+
+	return ret;
+}
+
+static void stop_func_tracer(struct trace_array *tr, int graph)
+{
+	tracer_enabled = 0;
+
+	unregister_wakeup_function(tr, graph);
+}
+
+/*
+ * Should this new latency be reported/recorded?
+ */
+static bool report_latency(struct trace_array *tr, u64 delta)
+{
+	if (tracing_thresh) {
+		if (delta < tracing_thresh)
+			return false;
+	} else {
+		if (delta <= tr->max_latency)
+			return false;
+	}
+	return true;
+}
+
+static void
+probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu)
+{
+	if (task != wakeup_task)
+		return;
+
+	wakeup_current_cpu = cpu;
+}
+
+static void
+tracing_sched_switch_trace(struct trace_array *tr,
+			   struct task_struct *prev,
+			   struct task_struct *next,
+			   unsigned int trace_ctx)
+{
+	struct trace_event_call *call = &event_context_switch;
+	struct trace_buffer *buffer = tr->array_buffer.buffer;
+	struct ring_buffer_event *event;
+	struct ctx_switch_entry *entry;
+
+	event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
+					  sizeof(*entry), trace_ctx);
+	if (!event)
+		return;
+	entry	= ring_buffer_event_data(event);
+	entry->prev_pid			= prev->pid;
+	entry->prev_prio		= prev->prio;
+	entry->prev_state		= task_state_index(prev);
+	entry->next_pid			= next->pid;
+	entry->next_prio		= next->prio;
+	entry->next_state		= task_state_index(next);
+	entry->next_cpu	= task_cpu(next);
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
+}
+
+static void
+tracing_sched_wakeup_trace(struct trace_array *tr,
+			   struct task_struct *wakee,
+			   struct task_struct *curr,
+			   unsigned int trace_ctx)
+{
+	struct trace_event_call *call = &event_wakeup;
+	struct ring_buffer_event *event;
+	struct ctx_switch_entry *entry;
+	struct trace_buffer *buffer = tr->array_buffer.buffer;
+
+	event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
+					  sizeof(*entry), trace_ctx);
+	if (!event)
+		return;
+	entry	= ring_buffer_event_data(event);
+	entry->prev_pid			= curr->pid;
+	entry->prev_prio		= curr->prio;
+	entry->prev_state		= task_state_index(curr);
+	entry->next_pid			= wakee->pid;
+	entry->next_prio		= wakee->prio;
+	entry->next_state		= task_state_index(wakee);
+	entry->next_cpu			= task_cpu(wakee);
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
+}
+
+static void notrace
+probe_wakeup_sched_switch(void *ignore, bool preempt,
+			  struct task_struct *prev, struct task_struct *next,
+			  unsigned int prev_state)
+{
+	struct trace_array_cpu *data;
+	u64 T0, T1, delta;
+	unsigned long flags;
+	long disabled;
+	int cpu;
+	unsigned int trace_ctx;
+
+	tracing_record_cmdline(prev);
+
+	if (unlikely(!tracer_enabled))
+		return;
+
+	/*
+	 * When we start a new trace, we set wakeup_task to NULL
+	 * and then set tracer_enabled = 1. We want to make sure
+	 * that another CPU does not see the tracer_enabled = 1
+	 * and the wakeup_task with an older task, that might
+	 * actually be the same as next.
+	 */
+	smp_rmb();
+
+	if (next != wakeup_task)
+		return;
+
+	/* disable local data, not wakeup_cpu data */
+	cpu = raw_smp_processor_id();
+	disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
+	if (likely(disabled != 1))
+		goto out;
+
+	local_irq_save(flags);
+	trace_ctx = tracing_gen_ctx_flags(flags);
+
+	arch_spin_lock(&wakeup_lock);
+
+	/* We could race with grabbing wakeup_lock */
+	if (unlikely(!tracer_enabled || next != wakeup_task))
+		goto out_unlock;
+
+	/* The task we are waiting for is waking up */
+	data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
+
+	__trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, trace_ctx);
+	tracing_sched_switch_trace(wakeup_trace, prev, next, trace_ctx);
+	__trace_stack(wakeup_trace, trace_ctx, 0);
+
+	T0 = data->preempt_timestamp;
+	T1 = ftrace_now(cpu);
+	delta = T1-T0;
+
+	if (!report_latency(wakeup_trace, delta))
+		goto out_unlock;
+
+	if (likely(!is_tracing_stopped())) {
+		wakeup_trace->max_latency = delta;
+		update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu, NULL);
+	}
+
+out_unlock:
+	__wakeup_reset(wakeup_trace);
+	arch_spin_unlock(&wakeup_lock);
+	local_irq_restore(flags);
+out:
+	atomic_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
+}
+
+static void __wakeup_reset(struct trace_array *tr)
+{
+	wakeup_cpu = -1;
+	wakeup_prio = -1;
+	tracing_dl = false;
+
+	if (wakeup_task)
+		put_task_struct(wakeup_task);
+
+	wakeup_task = NULL;
+}
+
+static void wakeup_reset(struct trace_array *tr)
+{
+	unsigned long flags;
+
+	tracing_reset_online_cpus(&tr->array_buffer);
+
+	local_irq_save(flags);
+	arch_spin_lock(&wakeup_lock);
+	__wakeup_reset(tr);
+	arch_spin_unlock(&wakeup_lock);
+	local_irq_restore(flags);
+}
+
+static void
+probe_wakeup(void *ignore, struct task_struct *p)
+{
+	struct trace_array_cpu *data;
+	int cpu = smp_processor_id();
+	long disabled;
+	unsigned int trace_ctx;
+
+	if (likely(!tracer_enabled))
+		return;
+
+	tracing_record_cmdline(p);
+	tracing_record_cmdline(current);
+
+	/*
+	 * Semantic is like this:
+	 *  - wakeup tracer handles all tasks in the system, independently
+	 *    from their scheduling class;
+	 *  - wakeup_rt tracer handles tasks belonging to sched_dl and
+	 *    sched_rt class;
+	 *  - wakeup_dl handles tasks belonging to sched_dl class only.
+	 */
+	if (tracing_dl || (wakeup_dl && !dl_task(p)) ||
+	    (wakeup_rt && !dl_task(p) && !rt_task(p)) ||
+	    (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
+		return;
+
+	disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
+	if (unlikely(disabled != 1))
+		goto out;
+
+	trace_ctx = tracing_gen_ctx();
+
+	/* interrupts should be off from try_to_wake_up */
+	arch_spin_lock(&wakeup_lock);
+
+	/* check for races. */
+	if (!tracer_enabled || tracing_dl ||
+	    (!dl_task(p) && p->prio >= wakeup_prio))
+		goto out_locked;
+
+	/* reset the trace */
+	__wakeup_reset(wakeup_trace);
+
+	wakeup_cpu = task_cpu(p);
+	wakeup_current_cpu = wakeup_cpu;
+	wakeup_prio = p->prio;
+
+	/*
+	 * Once you start tracing a -deadline task, don't bother tracing
+	 * another task until the first one wakes up.
+	 */
+	if (dl_task(p))
+		tracing_dl = true;
+	else
+		tracing_dl = false;
+
+	wakeup_task = get_task_struct(p);
+
+	data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
+	data->preempt_timestamp = ftrace_now(cpu);
+	tracing_sched_wakeup_trace(wakeup_trace, p, current, trace_ctx);
+	__trace_stack(wakeup_trace, trace_ctx, 0);
+
+	/*
+	 * We must be careful in using CALLER_ADDR2. But since wake_up
+	 * is not called by an assembly function  (where as schedule is)
+	 * it should be safe to use it here.
+	 */
+	__trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, trace_ctx);
+
+out_locked:
+	arch_spin_unlock(&wakeup_lock);
+out:
+	atomic_dec(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
+}
+
+static void start_wakeup_tracer(struct trace_array *tr)
+{
+	int ret;
+
+	ret = register_trace_sched_wakeup(probe_wakeup, NULL);
+	if (ret) {
+		pr_info("wakeup trace: Couldn't activate tracepoint"
+			" probe to kernel_sched_wakeup\n");
+		return;
+	}
+
+	ret = register_trace_sched_wakeup_new(probe_wakeup, NULL);
+	if (ret) {
+		pr_info("wakeup trace: Couldn't activate tracepoint"
+			" probe to kernel_sched_wakeup_new\n");
+		goto fail_deprobe;
+	}
+
+	ret = register_trace_sched_switch(probe_wakeup_sched_switch, NULL);
+	if (ret) {
+		pr_info("sched trace: Couldn't activate tracepoint"
+			" probe to kernel_sched_switch\n");
+		goto fail_deprobe_wake_new;
+	}
+
+	ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
+	if (ret) {
+		pr_info("wakeup trace: Couldn't activate tracepoint"
+			" probe to kernel_sched_migrate_task\n");
+		goto fail_deprobe_sched_switch;
+	}
+
+	wakeup_reset(tr);
+
+	/*
+	 * Don't let the tracer_enabled = 1 show up before
+	 * the wakeup_task is reset. This may be overkill since
+	 * wakeup_reset does a spin_unlock after setting the
+	 * wakeup_task to NULL, but I want to be safe.
+	 * This is a slow path anyway.
+	 */
+	smp_wmb();
+
+	if (start_func_tracer(tr, is_graph(tr)))
+		printk(KERN_ERR "failed to start wakeup tracer\n");
+
+	return;
+fail_deprobe_sched_switch:
+	unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
+fail_deprobe_wake_new:
+	unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
+fail_deprobe:
+	unregister_trace_sched_wakeup(probe_wakeup, NULL);
+}
+
+static void stop_wakeup_tracer(struct trace_array *tr)
+{
+	tracer_enabled = 0;
+	stop_func_tracer(tr, is_graph(tr));
+	unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
+	unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
+	unregister_trace_sched_wakeup(probe_wakeup, NULL);
+	unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL);
+}
+
+static bool wakeup_busy;
+
+static int __wakeup_tracer_init(struct trace_array *tr)
+{
+	save_flags = tr->trace_flags;
+
+	/* non overwrite screws up the latency tracers */
+	set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
+	set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);
+
+	tr->max_latency = 0;
+	wakeup_trace = tr;
+	ftrace_init_array_ops(tr, wakeup_tracer_call);
+	start_wakeup_tracer(tr);
+
+	wakeup_busy = true;
+	return 0;
+}
+
+static int wakeup_tracer_init(struct trace_array *tr)
+{
+	if (wakeup_busy)
+		return -EBUSY;
+
+	wakeup_dl = false;
+	wakeup_rt = false;
+	return __wakeup_tracer_init(tr);
+}
+
+static int wakeup_rt_tracer_init(struct trace_array *tr)
+{
+	if (wakeup_busy)
+		return -EBUSY;
+
+	wakeup_dl = false;
+	wakeup_rt = true;
+	return __wakeup_tracer_init(tr);
+}
+
+static int wakeup_dl_tracer_init(struct trace_array *tr)
+{
+	if (wakeup_busy)
+		return -EBUSY;
+
+	wakeup_dl = true;
+	wakeup_rt = false;
+	return __wakeup_tracer_init(tr);
+}
+
+static void wakeup_tracer_reset(struct trace_array *tr)
+{
+	int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
+	int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
+
+	stop_wakeup_tracer(tr);
+	/* make sure we put back any tasks we are tracing */
+	wakeup_reset(tr);
+
+	set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
+	set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
+	ftrace_reset_array_ops(tr);
+	wakeup_busy = false;
+}
+
+static void wakeup_tracer_start(struct trace_array *tr)
+{
+	wakeup_reset(tr);
+	tracer_enabled = 1;
+}
+
+static void wakeup_tracer_stop(struct trace_array *tr)
+{
+	tracer_enabled = 0;
+}
+
+static struct tracer wakeup_tracer __read_mostly =
+{
+	.name		= "wakeup",
+	.init		= wakeup_tracer_init,
+	.reset		= wakeup_tracer_reset,
+	.start		= wakeup_tracer_start,
+	.stop		= wakeup_tracer_stop,
+	.print_max	= true,
+	.print_header	= wakeup_print_header,
+	.print_line	= wakeup_print_line,
+	.flag_changed	= wakeup_flag_changed,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest    = trace_selftest_startup_wakeup,
+#endif
+	.open		= wakeup_trace_open,
+	.close		= wakeup_trace_close,
+	.allow_instances = true,
+	.use_max_tr	= true,
+};
+
+static struct tracer wakeup_rt_tracer __read_mostly =
+{
+	.name		= "wakeup_rt",
+	.init		= wakeup_rt_tracer_init,
+	.reset		= wakeup_tracer_reset,
+	.start		= wakeup_tracer_start,
+	.stop		= wakeup_tracer_stop,
+	.print_max	= true,
+	.print_header	= wakeup_print_header,
+	.print_line	= wakeup_print_line,
+	.flag_changed	= wakeup_flag_changed,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest    = trace_selftest_startup_wakeup,
+#endif
+	.open		= wakeup_trace_open,
+	.close		= wakeup_trace_close,
+	.allow_instances = true,
+	.use_max_tr	= true,
+};
+
+static struct tracer wakeup_dl_tracer __read_mostly =
+{
+	.name		= "wakeup_dl",
+	.init		= wakeup_dl_tracer_init,
+	.reset		= wakeup_tracer_reset,
+	.start		= wakeup_tracer_start,
+	.stop		= wakeup_tracer_stop,
+	.print_max	= true,
+	.print_header	= wakeup_print_header,
+	.print_line	= wakeup_print_line,
+	.flag_changed	= wakeup_flag_changed,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest    = trace_selftest_startup_wakeup,
+#endif
+	.open		= wakeup_trace_open,
+	.close		= wakeup_trace_close,
+	.allow_instances = true,
+	.use_max_tr	= true,
+};
+
+__init static int init_wakeup_tracer(void)
+{
+	int ret;
+
+	ret = register_tracer(&wakeup_tracer);
+	if (ret)
+		return ret;
+
+	ret = register_tracer(&wakeup_rt_tracer);
+	if (ret)
+		return ret;
+
+	ret = register_tracer(&wakeup_dl_tracer);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+core_initcall(init_wakeup_tracer);
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
new file mode 100644
index 000000000..a2d301f58
--- /dev/null
+++ b/kernel/trace/trace_selftest.c
@@ -0,0 +1,1287 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Include in trace.c */
+
+#include <uapi/linux/sched/types.h>
+#include <linux/stringify.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+
+static inline int trace_valid_entry(struct trace_entry *entry)
+{
+	switch (entry->type) {
+	case TRACE_FN:
+	case TRACE_CTX:
+	case TRACE_WAKE:
+	case TRACE_STACK:
+	case TRACE_PRINT:
+	case TRACE_BRANCH:
+	case TRACE_GRAPH_ENT:
+	case TRACE_GRAPH_RET:
+		return 1;
+	}
+	return 0;
+}
+
+static int trace_test_buffer_cpu(struct array_buffer *buf, int cpu)
+{
+	struct ring_buffer_event *event;
+	struct trace_entry *entry;
+	unsigned int loops = 0;
+
+	while ((event = ring_buffer_consume(buf->buffer, cpu, NULL, NULL))) {
+		entry = ring_buffer_event_data(event);
+
+		/*
+		 * The ring buffer is a size of trace_buf_size, if
+		 * we loop more than the size, there's something wrong
+		 * with the ring buffer.
+		 */
+		if (loops++ > trace_buf_size) {
+			printk(KERN_CONT ".. bad ring buffer ");
+			goto failed;
+		}
+		if (!trace_valid_entry(entry)) {
+			printk(KERN_CONT ".. invalid entry %d ",
+				entry->type);
+			goto failed;
+		}
+	}
+	return 0;
+
+ failed:
+	/* disable tracing */
+	tracing_disabled = 1;
+	printk(KERN_CONT ".. corrupted trace buffer .. ");
+	return -1;
+}
+
+/*
+ * Test the trace buffer to see if all the elements
+ * are still sane.
+ */
+static int __maybe_unused trace_test_buffer(struct array_buffer *buf, unsigned long *count)
+{
+	unsigned long flags, cnt = 0;
+	int cpu, ret = 0;
+
+	/* Don't allow flipping of max traces now */
+	local_irq_save(flags);
+	arch_spin_lock(&buf->tr->max_lock);
+
+	cnt = ring_buffer_entries(buf->buffer);
+
+	/*
+	 * The trace_test_buffer_cpu runs a while loop to consume all data.
+	 * If the calling tracer is broken, and is constantly filling
+	 * the buffer, this will run forever, and hard lock the box.
+	 * We disable the ring buffer while we do this test to prevent
+	 * a hard lock up.
+	 */
+	tracing_off();
+	for_each_possible_cpu(cpu) {
+		ret = trace_test_buffer_cpu(buf, cpu);
+		if (ret)
+			break;
+	}
+	tracing_on();
+	arch_spin_unlock(&buf->tr->max_lock);
+	local_irq_restore(flags);
+
+	if (count)
+		*count = cnt;
+
+	return ret;
+}
+
+static inline void warn_failed_init_tracer(struct tracer *trace, int init_ret)
+{
+	printk(KERN_WARNING "Failed to init %s tracer, init returned %d\n",
+		trace->name, init_ret);
+}
+#ifdef CONFIG_FUNCTION_TRACER
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+static int trace_selftest_test_probe1_cnt;
+static void trace_selftest_test_probe1_func(unsigned long ip,
+					    unsigned long pip,
+					    struct ftrace_ops *op,
+					    struct ftrace_regs *fregs)
+{
+	trace_selftest_test_probe1_cnt++;
+}
+
+static int trace_selftest_test_probe2_cnt;
+static void trace_selftest_test_probe2_func(unsigned long ip,
+					    unsigned long pip,
+					    struct ftrace_ops *op,
+					    struct ftrace_regs *fregs)
+{
+	trace_selftest_test_probe2_cnt++;
+}
+
+static int trace_selftest_test_probe3_cnt;
+static void trace_selftest_test_probe3_func(unsigned long ip,
+					    unsigned long pip,
+					    struct ftrace_ops *op,
+					    struct ftrace_regs *fregs)
+{
+	trace_selftest_test_probe3_cnt++;
+}
+
+static int trace_selftest_test_global_cnt;
+static void trace_selftest_test_global_func(unsigned long ip,
+					    unsigned long pip,
+					    struct ftrace_ops *op,
+					    struct ftrace_regs *fregs)
+{
+	trace_selftest_test_global_cnt++;
+}
+
+static int trace_selftest_test_dyn_cnt;
+static void trace_selftest_test_dyn_func(unsigned long ip,
+					 unsigned long pip,
+					 struct ftrace_ops *op,
+					 struct ftrace_regs *fregs)
+{
+	trace_selftest_test_dyn_cnt++;
+}
+
+static struct ftrace_ops test_probe1 = {
+	.func			= trace_selftest_test_probe1_func,
+};
+
+static struct ftrace_ops test_probe2 = {
+	.func			= trace_selftest_test_probe2_func,
+};
+
+static struct ftrace_ops test_probe3 = {
+	.func			= trace_selftest_test_probe3_func,
+};
+
+static void print_counts(void)
+{
+	printk("(%d %d %d %d %d) ",
+	       trace_selftest_test_probe1_cnt,
+	       trace_selftest_test_probe2_cnt,
+	       trace_selftest_test_probe3_cnt,
+	       trace_selftest_test_global_cnt,
+	       trace_selftest_test_dyn_cnt);
+}
+
+static void reset_counts(void)
+{
+	trace_selftest_test_probe1_cnt = 0;
+	trace_selftest_test_probe2_cnt = 0;
+	trace_selftest_test_probe3_cnt = 0;
+	trace_selftest_test_global_cnt = 0;
+	trace_selftest_test_dyn_cnt = 0;
+}
+
+static int trace_selftest_ops(struct trace_array *tr, int cnt)
+{
+	int save_ftrace_enabled = ftrace_enabled;
+	struct ftrace_ops *dyn_ops;
+	char *func1_name;
+	char *func2_name;
+	int len1;
+	int len2;
+	int ret = -1;
+
+	printk(KERN_CONT "PASSED\n");
+	pr_info("Testing dynamic ftrace ops #%d: ", cnt);
+
+	ftrace_enabled = 1;
+	reset_counts();
+
+	/* Handle PPC64 '.' name */
+	func1_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
+	func2_name = "*" __stringify(DYN_FTRACE_TEST_NAME2);
+	len1 = strlen(func1_name);
+	len2 = strlen(func2_name);
+
+	/*
+	 * Probe 1 will trace function 1.
+	 * Probe 2 will trace function 2.
+	 * Probe 3 will trace functions 1 and 2.
+	 */
+	ftrace_set_filter(&test_probe1, func1_name, len1, 1);
+	ftrace_set_filter(&test_probe2, func2_name, len2, 1);
+	ftrace_set_filter(&test_probe3, func1_name, len1, 1);
+	ftrace_set_filter(&test_probe3, func2_name, len2, 0);
+
+	register_ftrace_function(&test_probe1);
+	register_ftrace_function(&test_probe2);
+	register_ftrace_function(&test_probe3);
+	/* First time we are running with main function */
+	if (cnt > 1) {
+		ftrace_init_array_ops(tr, trace_selftest_test_global_func);
+		register_ftrace_function(tr->ops);
+	}
+
+	DYN_FTRACE_TEST_NAME();
+
+	print_counts();
+
+	if (trace_selftest_test_probe1_cnt != 1)
+		goto out;
+	if (trace_selftest_test_probe2_cnt != 0)
+		goto out;
+	if (trace_selftest_test_probe3_cnt != 1)
+		goto out;
+	if (cnt > 1) {
+		if (trace_selftest_test_global_cnt == 0)
+			goto out;
+	}
+
+	DYN_FTRACE_TEST_NAME2();
+
+	print_counts();
+
+	if (trace_selftest_test_probe1_cnt != 1)
+		goto out;
+	if (trace_selftest_test_probe2_cnt != 1)
+		goto out;
+	if (trace_selftest_test_probe3_cnt != 2)
+		goto out;
+
+	/* Add a dynamic probe */
+	dyn_ops = kzalloc(sizeof(*dyn_ops), GFP_KERNEL);
+	if (!dyn_ops) {
+		printk("MEMORY ERROR ");
+		goto out;
+	}
+
+	dyn_ops->func = trace_selftest_test_dyn_func;
+
+	register_ftrace_function(dyn_ops);
+
+	trace_selftest_test_global_cnt = 0;
+
+	DYN_FTRACE_TEST_NAME();
+
+	print_counts();
+
+	if (trace_selftest_test_probe1_cnt != 2)
+		goto out_free;
+	if (trace_selftest_test_probe2_cnt != 1)
+		goto out_free;
+	if (trace_selftest_test_probe3_cnt != 3)
+		goto out_free;
+	if (cnt > 1) {
+		if (trace_selftest_test_global_cnt == 0)
+			goto out_free;
+	}
+	if (trace_selftest_test_dyn_cnt == 0)
+		goto out_free;
+
+	DYN_FTRACE_TEST_NAME2();
+
+	print_counts();
+
+	if (trace_selftest_test_probe1_cnt != 2)
+		goto out_free;
+	if (trace_selftest_test_probe2_cnt != 2)
+		goto out_free;
+	if (trace_selftest_test_probe3_cnt != 4)
+		goto out_free;
+
+	/* Remove trace function from probe 3 */
+	func1_name = "!" __stringify(DYN_FTRACE_TEST_NAME);
+	len1 = strlen(func1_name);
+
+	ftrace_set_filter(&test_probe3, func1_name, len1, 0);
+
+	DYN_FTRACE_TEST_NAME();
+
+	print_counts();
+
+	if (trace_selftest_test_probe1_cnt != 3)
+		goto out_free;
+	if (trace_selftest_test_probe2_cnt != 2)
+		goto out_free;
+	if (trace_selftest_test_probe3_cnt != 4)
+		goto out_free;
+	if (cnt > 1) {
+		if (trace_selftest_test_global_cnt == 0)
+			goto out_free;
+	}
+	if (trace_selftest_test_dyn_cnt == 0)
+		goto out_free;
+
+	DYN_FTRACE_TEST_NAME2();
+
+	print_counts();
+
+	if (trace_selftest_test_probe1_cnt != 3)
+		goto out_free;
+	if (trace_selftest_test_probe2_cnt != 3)
+		goto out_free;
+	if (trace_selftest_test_probe3_cnt != 5)
+		goto out_free;
+
+	ret = 0;
+ out_free:
+	unregister_ftrace_function(dyn_ops);
+	kfree(dyn_ops);
+
+ out:
+	/* Purposely unregister in the same order */
+	unregister_ftrace_function(&test_probe1);
+	unregister_ftrace_function(&test_probe2);
+	unregister_ftrace_function(&test_probe3);
+	if (cnt > 1)
+		unregister_ftrace_function(tr->ops);
+	ftrace_reset_array_ops(tr);
+
+	/* Make sure everything is off */
+	reset_counts();
+	DYN_FTRACE_TEST_NAME();
+	DYN_FTRACE_TEST_NAME();
+
+	if (trace_selftest_test_probe1_cnt ||
+	    trace_selftest_test_probe2_cnt ||
+	    trace_selftest_test_probe3_cnt ||
+	    trace_selftest_test_global_cnt ||
+	    trace_selftest_test_dyn_cnt)
+		ret = -1;
+
+	ftrace_enabled = save_ftrace_enabled;
+
+	return ret;
+}
+
+/* Test dynamic code modification and ftrace filters */
+static int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
+						  struct trace_array *tr,
+						  int (*func)(void))
+{
+	int save_ftrace_enabled = ftrace_enabled;
+	unsigned long count;
+	char *func_name;
+	int ret;
+
+	/* The ftrace test PASSED */
+	printk(KERN_CONT "PASSED\n");
+	pr_info("Testing dynamic ftrace: ");
+
+	/* enable tracing, and record the filter function */
+	ftrace_enabled = 1;
+
+	/* passed in by parameter to fool gcc from optimizing */
+	func();
+
+	/*
+	 * Some archs *cough*PowerPC*cough* add characters to the
+	 * start of the function names. We simply put a '*' to
+	 * accommodate them.
+	 */
+	func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
+
+	/* filter only on our function */
+	ftrace_set_global_filter(func_name, strlen(func_name), 1);
+
+	/* enable tracing */
+	ret = tracer_init(trace, tr);
+	if (ret) {
+		warn_failed_init_tracer(trace, ret);
+		goto out;
+	}
+
+	/* Sleep for a 1/10 of a second */
+	msleep(100);
+
+	/* we should have nothing in the buffer */
+	ret = trace_test_buffer(&tr->array_buffer, &count);
+	if (ret)
+		goto out;
+
+	if (count) {
+		ret = -1;
+		printk(KERN_CONT ".. filter did not filter .. ");
+		goto out;
+	}
+
+	/* call our function again */
+	func();
+
+	/* sleep again */
+	msleep(100);
+
+	/* stop the tracing. */
+	tracing_stop();
+	ftrace_enabled = 0;
+
+	/* check the trace buffer */
+	ret = trace_test_buffer(&tr->array_buffer, &count);
+
+	ftrace_enabled = 1;
+	tracing_start();
+
+	/* we should only have one item */
+	if (!ret && count != 1) {
+		trace->reset(tr);
+		printk(KERN_CONT ".. filter failed count=%ld ..", count);
+		ret = -1;
+		goto out;
+	}
+
+	/* Test the ops with global tracing running */
+	ret = trace_selftest_ops(tr, 1);
+	trace->reset(tr);
+
+ out:
+	ftrace_enabled = save_ftrace_enabled;
+
+	/* Enable tracing on all functions again */
+	ftrace_set_global_filter(NULL, 0, 1);
+
+	/* Test the ops with global tracing off */
+	if (!ret)
+		ret = trace_selftest_ops(tr, 2);
+
+	return ret;
+}
+
+static int trace_selftest_recursion_cnt;
+static void trace_selftest_test_recursion_func(unsigned long ip,
+					       unsigned long pip,
+					       struct ftrace_ops *op,
+					       struct ftrace_regs *fregs)
+{
+	/*
+	 * This function is registered without the recursion safe flag.
+	 * The ftrace infrastructure should provide the recursion
+	 * protection. If not, this will crash the kernel!
+	 */
+	if (trace_selftest_recursion_cnt++ > 10)
+		return;
+	DYN_FTRACE_TEST_NAME();
+}
+
+static void trace_selftest_test_recursion_safe_func(unsigned long ip,
+						    unsigned long pip,
+						    struct ftrace_ops *op,
+						    struct ftrace_regs *fregs)
+{
+	/*
+	 * We said we would provide our own recursion. By calling
+	 * this function again, we should recurse back into this function
+	 * and count again. But this only happens if the arch supports
+	 * all of ftrace features and nothing else is using the function
+	 * tracing utility.
+	 */
+	if (trace_selftest_recursion_cnt++)
+		return;
+	DYN_FTRACE_TEST_NAME();
+}
+
+static struct ftrace_ops test_rec_probe = {
+	.func			= trace_selftest_test_recursion_func,
+	.flags			= FTRACE_OPS_FL_RECURSION,
+};
+
+static struct ftrace_ops test_recsafe_probe = {
+	.func			= trace_selftest_test_recursion_safe_func,
+};
+
+static int
+trace_selftest_function_recursion(void)
+{
+	int save_ftrace_enabled = ftrace_enabled;
+	char *func_name;
+	int len;
+	int ret;
+
+	/* The previous test PASSED */
+	pr_cont("PASSED\n");
+	pr_info("Testing ftrace recursion: ");
+
+
+	/* enable tracing, and record the filter function */
+	ftrace_enabled = 1;
+
+	/* Handle PPC64 '.' name */
+	func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
+	len = strlen(func_name);
+
+	ret = ftrace_set_filter(&test_rec_probe, func_name, len, 1);
+	if (ret) {
+		pr_cont("*Could not set filter* ");
+		goto out;
+	}
+
+	ret = register_ftrace_function(&test_rec_probe);
+	if (ret) {
+		pr_cont("*could not register callback* ");
+		goto out;
+	}
+
+	DYN_FTRACE_TEST_NAME();
+
+	unregister_ftrace_function(&test_rec_probe);
+
+	ret = -1;
+	/*
+	 * Recursion allows for transitions between context,
+	 * and may call the callback twice.
+	 */
+	if (trace_selftest_recursion_cnt != 1 &&
+	    trace_selftest_recursion_cnt != 2) {
+		pr_cont("*callback not called once (or twice) (%d)* ",
+			trace_selftest_recursion_cnt);
+		goto out;
+	}
+
+	trace_selftest_recursion_cnt = 1;
+
+	pr_cont("PASSED\n");
+	pr_info("Testing ftrace recursion safe: ");
+
+	ret = ftrace_set_filter(&test_recsafe_probe, func_name, len, 1);
+	if (ret) {
+		pr_cont("*Could not set filter* ");
+		goto out;
+	}
+
+	ret = register_ftrace_function(&test_recsafe_probe);
+	if (ret) {
+		pr_cont("*could not register callback* ");
+		goto out;
+	}
+
+	DYN_FTRACE_TEST_NAME();
+
+	unregister_ftrace_function(&test_recsafe_probe);
+
+	ret = -1;
+	if (trace_selftest_recursion_cnt != 2) {
+		pr_cont("*callback not called expected 2 times (%d)* ",
+			trace_selftest_recursion_cnt);
+		goto out;
+	}
+
+	ret = 0;
+out:
+	ftrace_enabled = save_ftrace_enabled;
+
+	return ret;
+}
+#else
+# define trace_selftest_startup_dynamic_tracing(trace, tr, func) ({ 0; })
+# define trace_selftest_function_recursion() ({ 0; })
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+static enum {
+	TRACE_SELFTEST_REGS_START,
+	TRACE_SELFTEST_REGS_FOUND,
+	TRACE_SELFTEST_REGS_NOT_FOUND,
+} trace_selftest_regs_stat;
+
+static void trace_selftest_test_regs_func(unsigned long ip,
+					  unsigned long pip,
+					  struct ftrace_ops *op,
+					  struct ftrace_regs *fregs)
+{
+	struct pt_regs *regs = ftrace_get_regs(fregs);
+
+	if (regs)
+		trace_selftest_regs_stat = TRACE_SELFTEST_REGS_FOUND;
+	else
+		trace_selftest_regs_stat = TRACE_SELFTEST_REGS_NOT_FOUND;
+}
+
+static struct ftrace_ops test_regs_probe = {
+	.func		= trace_selftest_test_regs_func,
+	.flags		= FTRACE_OPS_FL_SAVE_REGS,
+};
+
+static int
+trace_selftest_function_regs(void)
+{
+	int save_ftrace_enabled = ftrace_enabled;
+	char *func_name;
+	int len;
+	int ret;
+	int supported = 0;
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+	supported = 1;
+#endif
+
+	/* The previous test PASSED */
+	pr_cont("PASSED\n");
+	pr_info("Testing ftrace regs%s: ",
+		!supported ? "(no arch support)" : "");
+
+	/* enable tracing, and record the filter function */
+	ftrace_enabled = 1;
+
+	/* Handle PPC64 '.' name */
+	func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
+	len = strlen(func_name);
+
+	ret = ftrace_set_filter(&test_regs_probe, func_name, len, 1);
+	/*
+	 * If DYNAMIC_FTRACE is not set, then we just trace all functions.
+	 * This test really doesn't care.
+	 */
+	if (ret && ret != -ENODEV) {
+		pr_cont("*Could not set filter* ");
+		goto out;
+	}
+
+	ret = register_ftrace_function(&test_regs_probe);
+	/*
+	 * Now if the arch does not support passing regs, then this should
+	 * have failed.
+	 */
+	if (!supported) {
+		if (!ret) {
+			pr_cont("*registered save-regs without arch support* ");
+			goto out;
+		}
+		test_regs_probe.flags |= FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED;
+		ret = register_ftrace_function(&test_regs_probe);
+	}
+	if (ret) {
+		pr_cont("*could not register callback* ");
+		goto out;
+	}
+
+
+	DYN_FTRACE_TEST_NAME();
+
+	unregister_ftrace_function(&test_regs_probe);
+
+	ret = -1;
+
+	switch (trace_selftest_regs_stat) {
+	case TRACE_SELFTEST_REGS_START:
+		pr_cont("*callback never called* ");
+		goto out;
+
+	case TRACE_SELFTEST_REGS_FOUND:
+		if (supported)
+			break;
+		pr_cont("*callback received regs without arch support* ");
+		goto out;
+
+	case TRACE_SELFTEST_REGS_NOT_FOUND:
+		if (!supported)
+			break;
+		pr_cont("*callback received NULL regs* ");
+		goto out;
+	}
+
+	ret = 0;
+out:
+	ftrace_enabled = save_ftrace_enabled;
+
+	return ret;
+}
+
+/*
+ * Simple verification test of ftrace function tracer.
+ * Enable ftrace, sleep 1/10 second, and then read the trace
+ * buffer to see if all is in order.
+ */
+__init int
+trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
+{
+	int save_ftrace_enabled = ftrace_enabled;
+	unsigned long count;
+	int ret;
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+	if (ftrace_filter_param) {
+		printk(KERN_CONT " ... kernel command line filter set: force PASS ... ");
+		return 0;
+	}
+#endif
+
+	/* make sure msleep has been recorded */
+	msleep(1);
+
+	/* start the tracing */
+	ftrace_enabled = 1;
+
+	ret = tracer_init(trace, tr);
+	if (ret) {
+		warn_failed_init_tracer(trace, ret);
+		goto out;
+	}
+
+	/* Sleep for a 1/10 of a second */
+	msleep(100);
+	/* stop the tracing. */
+	tracing_stop();
+	ftrace_enabled = 0;
+
+	/* check the trace buffer */
+	ret = trace_test_buffer(&tr->array_buffer, &count);
+
+	ftrace_enabled = 1;
+	trace->reset(tr);
+	tracing_start();
+
+	if (!ret && !count) {
+		printk(KERN_CONT ".. no entries found ..");
+		ret = -1;
+		goto out;
+	}
+
+	ret = trace_selftest_startup_dynamic_tracing(trace, tr,
+						     DYN_FTRACE_TEST_NAME);
+	if (ret)
+		goto out;
+
+	ret = trace_selftest_function_recursion();
+	if (ret)
+		goto out;
+
+	ret = trace_selftest_function_regs();
+ out:
+	ftrace_enabled = save_ftrace_enabled;
+
+	/* kill ftrace totally if we failed */
+	if (ret)
+		ftrace_kill();
+
+	return ret;
+}
+#endif /* CONFIG_FUNCTION_TRACER */
+
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+/* Maximum number of functions to trace before diagnosing a hang */
+#define GRAPH_MAX_FUNC_TEST	100000000
+
+static unsigned int graph_hang_thresh;
+
+/* Wrap the real function entry probe to avoid possible hanging */
+static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace)
+{
+	/* This is harmlessly racy, we want to approximately detect a hang */
+	if (unlikely(++graph_hang_thresh > GRAPH_MAX_FUNC_TEST)) {
+		ftrace_graph_stop();
+		printk(KERN_WARNING "BUG: Function graph tracer hang!\n");
+		if (ftrace_dump_on_oops) {
+			ftrace_dump(DUMP_ALL);
+			/* ftrace_dump() disables tracing */
+			tracing_on();
+		}
+		return 0;
+	}
+
+	return trace_graph_entry(trace);
+}
+
+static struct fgraph_ops fgraph_ops __initdata  = {
+	.entryfunc		= &trace_graph_entry_watchdog,
+	.retfunc		= &trace_graph_return,
+};
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+noinline __noclone static void trace_direct_tramp(void) { }
+#endif
+
+/*
+ * Pretty much the same than for the function tracer from which the selftest
+ * has been borrowed.
+ */
+__init int
+trace_selftest_startup_function_graph(struct tracer *trace,
+					struct trace_array *tr)
+{
+	int ret;
+	unsigned long count;
+	char *func_name __maybe_unused;
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+	if (ftrace_filter_param) {
+		printk(KERN_CONT " ... kernel command line filter set: force PASS ... ");
+		return 0;
+	}
+#endif
+
+	/*
+	 * Simulate the init() callback but we attach a watchdog callback
+	 * to detect and recover from possible hangs
+	 */
+	tracing_reset_online_cpus(&tr->array_buffer);
+	set_graph_array(tr);
+	ret = register_ftrace_graph(&fgraph_ops);
+	if (ret) {
+		warn_failed_init_tracer(trace, ret);
+		goto out;
+	}
+	tracing_start_cmdline_record();
+
+	/* Sleep for a 1/10 of a second */
+	msleep(100);
+
+	/* Have we just recovered from a hang? */
+	if (graph_hang_thresh > GRAPH_MAX_FUNC_TEST) {
+		disable_tracing_selftest("recovering from a hang");
+		ret = -1;
+		goto out;
+	}
+
+	tracing_stop();
+
+	/* check the trace buffer */
+	ret = trace_test_buffer(&tr->array_buffer, &count);
+
+	/* Need to also simulate the tr->reset to remove this fgraph_ops */
+	tracing_stop_cmdline_record();
+	unregister_ftrace_graph(&fgraph_ops);
+
+	tracing_start();
+
+	if (!ret && !count) {
+		printk(KERN_CONT ".. no entries found ..");
+		ret = -1;
+		goto out;
+	}
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	tracing_reset_online_cpus(&tr->array_buffer);
+	set_graph_array(tr);
+
+	/*
+	 * Some archs *cough*PowerPC*cough* add characters to the
+	 * start of the function names. We simply put a '*' to
+	 * accommodate them.
+	 */
+	func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
+	ftrace_set_global_filter(func_name, strlen(func_name), 1);
+
+	/*
+	 * Register direct function together with graph tracer
+	 * and make sure we get graph trace.
+	 */
+	ret = register_ftrace_direct((unsigned long) DYN_FTRACE_TEST_NAME,
+				     (unsigned long) trace_direct_tramp);
+	if (ret)
+		goto out;
+
+	ret = register_ftrace_graph(&fgraph_ops);
+	if (ret) {
+		warn_failed_init_tracer(trace, ret);
+		goto out;
+	}
+
+	DYN_FTRACE_TEST_NAME();
+
+	count = 0;
+
+	tracing_stop();
+	/* check the trace buffer */
+	ret = trace_test_buffer(&tr->array_buffer, &count);
+
+	unregister_ftrace_graph(&fgraph_ops);
+
+	ret = unregister_ftrace_direct((unsigned long) DYN_FTRACE_TEST_NAME,
+				       (unsigned long) trace_direct_tramp);
+	if (ret)
+		goto out;
+
+	tracing_start();
+
+	if (!ret && !count) {
+		ret = -1;
+		goto out;
+	}
+
+	/* Enable tracing on all functions again */
+	ftrace_set_global_filter(NULL, 0, 1);
+#endif
+
+	/* Don't test dynamic tracing, the function tracer already did */
+out:
+	/* Stop it if we failed */
+	if (ret)
+		ftrace_graph_stop();
+
+	return ret;
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+
+#ifdef CONFIG_IRQSOFF_TRACER
+int
+trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
+{
+	unsigned long save_max = tr->max_latency;
+	unsigned long count;
+	int ret;
+
+	/* start the tracing */
+	ret = tracer_init(trace, tr);
+	if (ret) {
+		warn_failed_init_tracer(trace, ret);
+		return ret;
+	}
+
+	/* reset the max latency */
+	tr->max_latency = 0;
+	/* disable interrupts for a bit */
+	local_irq_disable();
+	udelay(100);
+	local_irq_enable();
+
+	/*
+	 * Stop the tracer to avoid a warning subsequent
+	 * to buffer flipping failure because tracing_stop()
+	 * disables the tr and max buffers, making flipping impossible
+	 * in case of parallels max irqs off latencies.
+	 */
+	trace->stop(tr);
+	/* stop the tracing. */
+	tracing_stop();
+	/* check both trace buffers */
+	ret = trace_test_buffer(&tr->array_buffer, NULL);
+	if (!ret)
+		ret = trace_test_buffer(&tr->max_buffer, &count);
+	trace->reset(tr);
+	tracing_start();
+
+	if (!ret && !count) {
+		printk(KERN_CONT ".. no entries found ..");
+		ret = -1;
+	}
+
+	tr->max_latency = save_max;
+
+	return ret;
+}
+#endif /* CONFIG_IRQSOFF_TRACER */
+
+#ifdef CONFIG_PREEMPT_TRACER
+int
+trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
+{
+	unsigned long save_max = tr->max_latency;
+	unsigned long count;
+	int ret;
+
+	/*
+	 * Now that the big kernel lock is no longer preemptible,
+	 * and this is called with the BKL held, it will always
+	 * fail. If preemption is already disabled, simply
+	 * pass the test. When the BKL is removed, or becomes
+	 * preemptible again, we will once again test this,
+	 * so keep it in.
+	 */
+	if (preempt_count()) {
+		printk(KERN_CONT "can not test ... force ");
+		return 0;
+	}
+
+	/* start the tracing */
+	ret = tracer_init(trace, tr);
+	if (ret) {
+		warn_failed_init_tracer(trace, ret);
+		return ret;
+	}
+
+	/* reset the max latency */
+	tr->max_latency = 0;
+	/* disable preemption for a bit */
+	preempt_disable();
+	udelay(100);
+	preempt_enable();
+
+	/*
+	 * Stop the tracer to avoid a warning subsequent
+	 * to buffer flipping failure because tracing_stop()
+	 * disables the tr and max buffers, making flipping impossible
+	 * in case of parallels max preempt off latencies.
+	 */
+	trace->stop(tr);
+	/* stop the tracing. */
+	tracing_stop();
+	/* check both trace buffers */
+	ret = trace_test_buffer(&tr->array_buffer, NULL);
+	if (!ret)
+		ret = trace_test_buffer(&tr->max_buffer, &count);
+	trace->reset(tr);
+	tracing_start();
+
+	if (!ret && !count) {
+		printk(KERN_CONT ".. no entries found ..");
+		ret = -1;
+	}
+
+	tr->max_latency = save_max;
+
+	return ret;
+}
+#endif /* CONFIG_PREEMPT_TRACER */
+
+#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
+int
+trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr)
+{
+	unsigned long save_max = tr->max_latency;
+	unsigned long count;
+	int ret;
+
+	/*
+	 * Now that the big kernel lock is no longer preemptible,
+	 * and this is called with the BKL held, it will always
+	 * fail. If preemption is already disabled, simply
+	 * pass the test. When the BKL is removed, or becomes
+	 * preemptible again, we will once again test this,
+	 * so keep it in.
+	 */
+	if (preempt_count()) {
+		printk(KERN_CONT "can not test ... force ");
+		return 0;
+	}
+
+	/* start the tracing */
+	ret = tracer_init(trace, tr);
+	if (ret) {
+		warn_failed_init_tracer(trace, ret);
+		goto out_no_start;
+	}
+
+	/* reset the max latency */
+	tr->max_latency = 0;
+
+	/* disable preemption and interrupts for a bit */
+	preempt_disable();
+	local_irq_disable();
+	udelay(100);
+	preempt_enable();
+	/* reverse the order of preempt vs irqs */
+	local_irq_enable();
+
+	/*
+	 * Stop the tracer to avoid a warning subsequent
+	 * to buffer flipping failure because tracing_stop()
+	 * disables the tr and max buffers, making flipping impossible
+	 * in case of parallels max irqs/preempt off latencies.
+	 */
+	trace->stop(tr);
+	/* stop the tracing. */
+	tracing_stop();
+	/* check both trace buffers */
+	ret = trace_test_buffer(&tr->array_buffer, NULL);
+	if (ret)
+		goto out;
+
+	ret = trace_test_buffer(&tr->max_buffer, &count);
+	if (ret)
+		goto out;
+
+	if (!ret && !count) {
+		printk(KERN_CONT ".. no entries found ..");
+		ret = -1;
+		goto out;
+	}
+
+	/* do the test by disabling interrupts first this time */
+	tr->max_latency = 0;
+	tracing_start();
+	trace->start(tr);
+
+	preempt_disable();
+	local_irq_disable();
+	udelay(100);
+	preempt_enable();
+	/* reverse the order of preempt vs irqs */
+	local_irq_enable();
+
+	trace->stop(tr);
+	/* stop the tracing. */
+	tracing_stop();
+	/* check both trace buffers */
+	ret = trace_test_buffer(&tr->array_buffer, NULL);
+	if (ret)
+		goto out;
+
+	ret = trace_test_buffer(&tr->max_buffer, &count);
+
+	if (!ret && !count) {
+		printk(KERN_CONT ".. no entries found ..");
+		ret = -1;
+		goto out;
+	}
+
+out:
+	tracing_start();
+out_no_start:
+	trace->reset(tr);
+	tr->max_latency = save_max;
+
+	return ret;
+}
+#endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */
+
+#ifdef CONFIG_NOP_TRACER
+int
+trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr)
+{
+	/* What could possibly go wrong? */
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_SCHED_TRACER
+
+struct wakeup_test_data {
+	struct completion	is_ready;
+	int			go;
+};
+
+static int trace_wakeup_test_thread(void *data)
+{
+	/* Make this a -deadline thread */
+	static const struct sched_attr attr = {
+		.sched_policy = SCHED_DEADLINE,
+		.sched_runtime = 100000ULL,
+		.sched_deadline = 10000000ULL,
+		.sched_period = 10000000ULL
+	};
+	struct wakeup_test_data *x = data;
+
+	sched_setattr(current, &attr);
+
+	/* Make it know we have a new prio */
+	complete(&x->is_ready);
+
+	/* now go to sleep and let the test wake us up */
+	set_current_state(TASK_INTERRUPTIBLE);
+	while (!x->go) {
+		schedule();
+		set_current_state(TASK_INTERRUPTIBLE);
+	}
+
+	complete(&x->is_ready);
+
+	set_current_state(TASK_INTERRUPTIBLE);
+
+	/* we are awake, now wait to disappear */
+	while (!kthread_should_stop()) {
+		schedule();
+		set_current_state(TASK_INTERRUPTIBLE);
+	}
+
+	__set_current_state(TASK_RUNNING);
+
+	return 0;
+}
+int
+trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
+{
+	unsigned long save_max = tr->max_latency;
+	struct task_struct *p;
+	struct wakeup_test_data data;
+	unsigned long count;
+	int ret;
+
+	memset(&data, 0, sizeof(data));
+
+	init_completion(&data.is_ready);
+
+	/* create a -deadline thread */
+	p = kthread_run(trace_wakeup_test_thread, &data, "ftrace-test");
+	if (IS_ERR(p)) {
+		printk(KERN_CONT "Failed to create ftrace wakeup test thread ");
+		return -1;
+	}
+
+	/* make sure the thread is running at -deadline policy */
+	wait_for_completion(&data.is_ready);
+
+	/* start the tracing */
+	ret = tracer_init(trace, tr);
+	if (ret) {
+		warn_failed_init_tracer(trace, ret);
+		return ret;
+	}
+
+	/* reset the max latency */
+	tr->max_latency = 0;
+
+	while (p->on_rq) {
+		/*
+		 * Sleep to make sure the -deadline thread is asleep too.
+		 * On virtual machines we can't rely on timings,
+		 * but we want to make sure this test still works.
+		 */
+		msleep(100);
+	}
+
+	init_completion(&data.is_ready);
+
+	data.go = 1;
+	/* memory barrier is in the wake_up_process() */
+
+	wake_up_process(p);
+
+	/* Wait for the task to wake up */
+	wait_for_completion(&data.is_ready);
+
+	/* stop the tracing. */
+	tracing_stop();
+	/* check both trace buffers */
+	ret = trace_test_buffer(&tr->array_buffer, NULL);
+	if (!ret)
+		ret = trace_test_buffer(&tr->max_buffer, &count);
+
+
+	trace->reset(tr);
+	tracing_start();
+
+	tr->max_latency = save_max;
+
+	/* kill the thread */
+	kthread_stop(p);
+
+	if (!ret && !count) {
+		printk(KERN_CONT ".. no entries found ..");
+		ret = -1;
+	}
+
+	return ret;
+}
+#endif /* CONFIG_SCHED_TRACER */
+
+#ifdef CONFIG_BRANCH_TRACER
+int
+trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
+{
+	unsigned long count;
+	int ret;
+
+	/* start the tracing */
+	ret = tracer_init(trace, tr);
+	if (ret) {
+		warn_failed_init_tracer(trace, ret);
+		return ret;
+	}
+
+	/* Sleep for a 1/10 of a second */
+	msleep(100);
+	/* stop the tracing. */
+	tracing_stop();
+	/* check the trace buffer */
+	ret = trace_test_buffer(&tr->array_buffer, &count);
+	trace->reset(tr);
+	tracing_start();
+
+	if (!ret && !count) {
+		printk(KERN_CONT ".. no entries found ..");
+		ret = -1;
+	}
+
+	return ret;
+}
+#endif /* CONFIG_BRANCH_TRACER */
+
diff --git a/kernel/trace/trace_selftest_dynamic.c b/kernel/trace/trace_selftest_dynamic.c
new file mode 100644
index 000000000..c364cf777
--- /dev/null
+++ b/kernel/trace/trace_selftest_dynamic.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/compiler.h>
+#include "trace.h"
+
+noinline __noclone int DYN_FTRACE_TEST_NAME(void)
+{
+	/* used to call mcount */
+	return 0;
+}
+
+noinline __noclone int DYN_FTRACE_TEST_NAME2(void)
+{
+	/* used to call mcount */
+	return 0;
+}
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
new file mode 100644
index 000000000..9c90b3a7d
--- /dev/null
+++ b/kernel/trace/trace_seq.c
@@ -0,0 +1,405 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_seq.c
+ *
+ * Copyright (C) 2008-2014 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ * The trace_seq is a handy tool that allows you to pass a descriptor around
+ * to a buffer that other functions can write to. It is similar to the
+ * seq_file functionality but has some differences.
+ *
+ * To use it, the trace_seq must be initialized with trace_seq_init().
+ * This will set up the counters within the descriptor. You can call
+ * trace_seq_init() more than once to reset the trace_seq to start
+ * from scratch.
+ * 
+ * The buffer size is currently PAGE_SIZE, although it may become dynamic
+ * in the future.
+ *
+ * A write to the buffer will either succeed or fail. That is, unlike
+ * sprintf() there will not be a partial write (well it may write into
+ * the buffer but it wont update the pointers). This allows users to
+ * try to write something into the trace_seq buffer and if it fails
+ * they can flush it and try again.
+ *
+ */
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+#include <linux/trace_seq.h>
+
+/* How much buffer is left on the trace_seq? */
+#define TRACE_SEQ_BUF_LEFT(s) seq_buf_buffer_left(&(s)->seq)
+
+/*
+ * trace_seq should work with being initialized with 0s.
+ */
+static inline void __trace_seq_init(struct trace_seq *s)
+{
+	if (unlikely(!s->seq.size))
+		trace_seq_init(s);
+}
+
+/**
+ * trace_print_seq - move the contents of trace_seq into a seq_file
+ * @m: the seq_file descriptor that is the destination
+ * @s: the trace_seq descriptor that is the source.
+ *
+ * Returns 0 on success and non zero on error. If it succeeds to
+ * write to the seq_file it will reset the trace_seq, otherwise
+ * it does not modify the trace_seq to let the caller try again.
+ */
+int trace_print_seq(struct seq_file *m, struct trace_seq *s)
+{
+	int ret;
+
+	__trace_seq_init(s);
+
+	ret = seq_buf_print_seq(m, &s->seq);
+
+	/*
+	 * Only reset this buffer if we successfully wrote to the
+	 * seq_file buffer. This lets the caller try again or
+	 * do something else with the contents.
+	 */
+	if (!ret)
+		trace_seq_init(s);
+
+	return ret;
+}
+
+/**
+ * trace_seq_printf - sequence printing of trace information
+ * @s: trace sequence descriptor
+ * @fmt: printf format string
+ *
+ * The tracer may use either sequence operations or its own
+ * copy to user routines. To simplify formatting of a trace
+ * trace_seq_printf() is used to store strings into a special
+ * buffer (@s). Then the output may be either used by
+ * the sequencer or pulled into another buffer.
+ */
+void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+{
+	unsigned int save_len = s->seq.len;
+	va_list ap;
+
+	if (s->full)
+		return;
+
+	__trace_seq_init(s);
+
+	va_start(ap, fmt);
+	seq_buf_vprintf(&s->seq, fmt, ap);
+	va_end(ap);
+
+	/* If we can't write it all, don't bother writing anything */
+	if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+		s->seq.len = save_len;
+		s->full = 1;
+	}
+}
+EXPORT_SYMBOL_GPL(trace_seq_printf);
+
+/**
+ * trace_seq_bitmask - write a bitmask array in its ASCII representation
+ * @s:		trace sequence descriptor
+ * @maskp:	points to an array of unsigned longs that represent a bitmask
+ * @nmaskbits:	The number of bits that are valid in @maskp
+ *
+ * Writes a ASCII representation of a bitmask string into @s.
+ */
+void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+		      int nmaskbits)
+{
+	unsigned int save_len = s->seq.len;
+
+	if (s->full)
+		return;
+
+	__trace_seq_init(s);
+
+	seq_buf_printf(&s->seq, "%*pb", nmaskbits, maskp);
+
+	if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+		s->seq.len = save_len;
+		s->full = 1;
+	}
+}
+EXPORT_SYMBOL_GPL(trace_seq_bitmask);
+
+/**
+ * trace_seq_vprintf - sequence printing of trace information
+ * @s: trace sequence descriptor
+ * @fmt: printf format string
+ *
+ * The tracer may use either sequence operations or its own
+ * copy to user routines. To simplify formatting of a trace
+ * trace_seq_printf is used to store strings into a special
+ * buffer (@s). Then the output may be either used by
+ * the sequencer or pulled into another buffer.
+ */
+void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
+{
+	unsigned int save_len = s->seq.len;
+
+	if (s->full)
+		return;
+
+	__trace_seq_init(s);
+
+	seq_buf_vprintf(&s->seq, fmt, args);
+
+	/* If we can't write it all, don't bother writing anything */
+	if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+		s->seq.len = save_len;
+		s->full = 1;
+	}
+}
+EXPORT_SYMBOL_GPL(trace_seq_vprintf);
+
+/**
+ * trace_seq_bprintf - Write the printf string from binary arguments
+ * @s: trace sequence descriptor
+ * @fmt: The format string for the @binary arguments
+ * @binary: The binary arguments for @fmt.
+ *
+ * When recording in a fast path, a printf may be recorded with just
+ * saving the format and the arguments as they were passed to the
+ * function, instead of wasting cycles converting the arguments into
+ * ASCII characters. Instead, the arguments are saved in a 32 bit
+ * word array that is defined by the format string constraints.
+ *
+ * This function will take the format and the binary array and finish
+ * the conversion into the ASCII string within the buffer.
+ */
+void trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
+{
+	unsigned int save_len = s->seq.len;
+
+	if (s->full)
+		return;
+
+	__trace_seq_init(s);
+
+	seq_buf_bprintf(&s->seq, fmt, binary);
+
+	/* If we can't write it all, don't bother writing anything */
+	if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+		s->seq.len = save_len;
+		s->full = 1;
+		return;
+	}
+}
+EXPORT_SYMBOL_GPL(trace_seq_bprintf);
+
+/**
+ * trace_seq_puts - trace sequence printing of simple string
+ * @s: trace sequence descriptor
+ * @str: simple string to record
+ *
+ * The tracer may use either the sequence operations or its own
+ * copy to user routines. This function records a simple string
+ * into a special buffer (@s) for later retrieval by a sequencer
+ * or other mechanism.
+ */
+void trace_seq_puts(struct trace_seq *s, const char *str)
+{
+	unsigned int len = strlen(str);
+
+	if (s->full)
+		return;
+
+	__trace_seq_init(s);
+
+	if (len > TRACE_SEQ_BUF_LEFT(s)) {
+		s->full = 1;
+		return;
+	}
+
+	seq_buf_putmem(&s->seq, str, len);
+}
+EXPORT_SYMBOL_GPL(trace_seq_puts);
+
+/**
+ * trace_seq_putc - trace sequence printing of simple character
+ * @s: trace sequence descriptor
+ * @c: simple character to record
+ *
+ * The tracer may use either the sequence operations or its own
+ * copy to user routines. This function records a simple character
+ * into a special buffer (@s) for later retrieval by a sequencer
+ * or other mechanism.
+ */
+void trace_seq_putc(struct trace_seq *s, unsigned char c)
+{
+	if (s->full)
+		return;
+
+	__trace_seq_init(s);
+
+	if (TRACE_SEQ_BUF_LEFT(s) < 1) {
+		s->full = 1;
+		return;
+	}
+
+	seq_buf_putc(&s->seq, c);
+}
+EXPORT_SYMBOL_GPL(trace_seq_putc);
+
+/**
+ * trace_seq_putmem - write raw data into the trace_seq buffer
+ * @s: trace sequence descriptor
+ * @mem: The raw memory to copy into the buffer
+ * @len: The length of the raw memory to copy (in bytes)
+ *
+ * There may be cases where raw memory needs to be written into the
+ * buffer and a strcpy() would not work. Using this function allows
+ * for such cases.
+ */
+void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
+{
+	if (s->full)
+		return;
+
+	__trace_seq_init(s);
+
+	if (len > TRACE_SEQ_BUF_LEFT(s)) {
+		s->full = 1;
+		return;
+	}
+
+	seq_buf_putmem(&s->seq, mem, len);
+}
+EXPORT_SYMBOL_GPL(trace_seq_putmem);
+
+/**
+ * trace_seq_putmem_hex - write raw memory into the buffer in ASCII hex
+ * @s: trace sequence descriptor
+ * @mem: The raw memory to write its hex ASCII representation of
+ * @len: The length of the raw memory to copy (in bytes)
+ *
+ * This is similar to trace_seq_putmem() except instead of just copying the
+ * raw memory into the buffer it writes its ASCII representation of it
+ * in hex characters.
+ */
+void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+			 unsigned int len)
+{
+	unsigned int save_len = s->seq.len;
+
+	if (s->full)
+		return;
+
+	__trace_seq_init(s);
+
+	/* Each byte is represented by two chars */
+	if (len * 2 > TRACE_SEQ_BUF_LEFT(s)) {
+		s->full = 1;
+		return;
+	}
+
+	/* The added spaces can still cause an overflow */
+	seq_buf_putmem_hex(&s->seq, mem, len);
+
+	if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+		s->seq.len = save_len;
+		s->full = 1;
+		return;
+	}
+}
+EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
+
+/**
+ * trace_seq_path - copy a path into the sequence buffer
+ * @s: trace sequence descriptor
+ * @path: path to write into the sequence buffer.
+ *
+ * Write a path name into the sequence buffer.
+ *
+ * Returns 1 if we successfully written all the contents to
+ *   the buffer.
+ * Returns 0 if we the length to write is bigger than the
+ *   reserved buffer space. In this case, nothing gets written.
+ */
+int trace_seq_path(struct trace_seq *s, const struct path *path)
+{
+	unsigned int save_len = s->seq.len;
+
+	if (s->full)
+		return 0;
+
+	__trace_seq_init(s);
+
+	if (TRACE_SEQ_BUF_LEFT(s) < 1) {
+		s->full = 1;
+		return 0;
+	}
+
+	seq_buf_path(&s->seq, path, "\n");
+
+	if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+		s->seq.len = save_len;
+		s->full = 1;
+		return 0;
+	}
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(trace_seq_path);
+
+/**
+ * trace_seq_to_user - copy the sequence buffer to user space
+ * @s: trace sequence descriptor
+ * @ubuf: The userspace memory location to copy to
+ * @cnt: The amount to copy
+ *
+ * Copies the sequence buffer into the userspace memory pointed to
+ * by @ubuf. It starts from the last read position (@s->readpos)
+ * and writes up to @cnt characters or till it reaches the end of
+ * the content in the buffer (@s->len), which ever comes first.
+ *
+ * On success, it returns a positive number of the number of bytes
+ * it copied.
+ *
+ * On failure it returns -EBUSY if all of the content in the
+ * sequence has been already read, which includes nothing in the
+ * sequence (@s->len == @s->readpos).
+ *
+ * Returns -EFAULT if the copy to userspace fails.
+ */
+int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, int cnt)
+{
+	__trace_seq_init(s);
+	return seq_buf_to_user(&s->seq, ubuf, cnt);
+}
+EXPORT_SYMBOL_GPL(trace_seq_to_user);
+
+int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str,
+		       int prefix_type, int rowsize, int groupsize,
+		       const void *buf, size_t len, bool ascii)
+{
+	unsigned int save_len = s->seq.len;
+
+	if (s->full)
+		return 0;
+
+	__trace_seq_init(s);
+
+	if (TRACE_SEQ_BUF_LEFT(s) < 1) {
+		s->full = 1;
+		return 0;
+	}
+
+	seq_buf_hex_dump(&(s->seq), prefix_str,
+		   prefix_type, rowsize, groupsize,
+		   buf, len, ascii);
+
+	if (unlikely(seq_buf_has_overflowed(&s->seq))) {
+		s->seq.len = save_len;
+		s->full = 1;
+		return 0;
+	}
+
+	return 1;
+}
+EXPORT_SYMBOL(trace_seq_hex_dump);
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
new file mode 100644
index 000000000..5a48dba91
--- /dev/null
+++ b/kernel/trace/trace_stack.c
@@ -0,0 +1,582 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
+ *
+ */
+#include <linux/sched/task_stack.h>
+#include <linux/stacktrace.h>
+#include <linux/security.h>
+#include <linux/kallsyms.h>
+#include <linux/seq_file.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+#include <linux/module.h>
+#include <linux/sysctl.h>
+#include <linux/init.h>
+
+#include <asm/setup.h>
+
+#include "trace.h"
+
+#define STACK_TRACE_ENTRIES 500
+
+static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES];
+static unsigned stack_trace_index[STACK_TRACE_ENTRIES];
+
+static unsigned int stack_trace_nr_entries;
+static unsigned long stack_trace_max_size;
+static arch_spinlock_t stack_trace_max_lock =
+	(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+
+DEFINE_PER_CPU(int, disable_stack_tracer);
+static DEFINE_MUTEX(stack_sysctl_mutex);
+
+int stack_tracer_enabled;
+
+static void print_max_stack(void)
+{
+	long i;
+	int size;
+
+	pr_emerg("        Depth    Size   Location    (%d entries)\n"
+			   "        -----    ----   --------\n",
+			   stack_trace_nr_entries);
+
+	for (i = 0; i < stack_trace_nr_entries; i++) {
+		if (i + 1 == stack_trace_nr_entries)
+			size = stack_trace_index[i];
+		else
+			size = stack_trace_index[i] - stack_trace_index[i+1];
+
+		pr_emerg("%3ld) %8d   %5d   %pS\n", i, stack_trace_index[i],
+				size, (void *)stack_dump_trace[i]);
+	}
+}
+
+/*
+ * The stack tracer looks for a maximum stack at each call from a function. It
+ * registers a callback from ftrace, and in that callback it examines the stack
+ * size. It determines the stack size from the variable passed in, which is the
+ * address of a local variable in the stack_trace_call() callback function.
+ * The stack size is calculated by the address of the local variable to the top
+ * of the current stack. If that size is smaller than the currently saved max
+ * stack size, nothing more is done.
+ *
+ * If the size of the stack is greater than the maximum recorded size, then the
+ * following algorithm takes place.
+ *
+ * For architectures (like x86) that store the function's return address before
+ * saving the function's local variables, the stack will look something like
+ * this:
+ *
+ *   [ top of stack ]
+ *    0: sys call entry frame
+ *   10: return addr to entry code
+ *   11: start of sys_foo frame
+ *   20: return addr to sys_foo
+ *   21: start of kernel_func_bar frame
+ *   30: return addr to kernel_func_bar
+ *   31: [ do trace stack here ]
+ *
+ * The save_stack_trace() is called returning all the functions it finds in the
+ * current stack. Which would be (from the bottom of the stack to the top):
+ *
+ *   return addr to kernel_func_bar
+ *   return addr to sys_foo
+ *   return addr to entry code
+ *
+ * Now to figure out how much each of these functions' local variable size is,
+ * a search of the stack is made to find these values. When a match is made, it
+ * is added to the stack_dump_trace[] array. The offset into the stack is saved
+ * in the stack_trace_index[] array. The above example would show:
+ *
+ *        stack_dump_trace[]        |   stack_trace_index[]
+ *        ------------------        +   -------------------
+ *  return addr to kernel_func_bar  |          30
+ *  return addr to sys_foo          |          20
+ *  return addr to entry            |          10
+ *
+ * The print_max_stack() function above, uses these values to print the size of
+ * each function's portion of the stack.
+ *
+ *  for (i = 0; i < nr_entries; i++) {
+ *     size = i == nr_entries - 1 ? stack_trace_index[i] :
+ *                    stack_trace_index[i] - stack_trace_index[i+1]
+ *     print "%d %d %d %s\n", i, stack_trace_index[i], size, stack_dump_trace[i]);
+ *  }
+ *
+ * The above shows
+ *
+ *     depth size  location
+ *     ----- ----  --------
+ *  0    30   10   kernel_func_bar
+ *  1    20   10   sys_foo
+ *  2    10   10   entry code
+ *
+ * Now for architectures that might save the return address after the functions
+ * local variables (saving the link register before calling nested functions),
+ * this will cause the stack to look a little different:
+ *
+ * [ top of stack ]
+ *  0: sys call entry frame
+ * 10: start of sys_foo_frame
+ * 19: return addr to entry code << lr saved before calling kernel_func_bar
+ * 20: start of kernel_func_bar frame
+ * 29: return addr to sys_foo_frame << lr saved before calling next function
+ * 30: [ do trace stack here ]
+ *
+ * Although the functions returned by save_stack_trace() may be the same, the
+ * placement in the stack will be different. Using the same algorithm as above
+ * would yield:
+ *
+ *        stack_dump_trace[]        |   stack_trace_index[]
+ *        ------------------        +   -------------------
+ *  return addr to kernel_func_bar  |          30
+ *  return addr to sys_foo          |          29
+ *  return addr to entry            |          19
+ *
+ * Where the mapping is off by one:
+ *
+ *   kernel_func_bar stack frame size is 29 - 19 not 30 - 29!
+ *
+ * To fix this, if the architecture sets ARCH_RET_ADDR_AFTER_LOCAL_VARS the
+ * values in stack_trace_index[] are shifted by one to and the number of
+ * stack trace entries is decremented by one.
+ *
+ *        stack_dump_trace[]        |   stack_trace_index[]
+ *        ------------------        +   -------------------
+ *  return addr to kernel_func_bar  |          29
+ *  return addr to sys_foo          |          19
+ *
+ * Although the entry function is not displayed, the first function (sys_foo)
+ * will still include the stack size of it.
+ */
+static void check_stack(unsigned long ip, unsigned long *stack)
+{
+	unsigned long this_size, flags; unsigned long *p, *top, *start;
+	static int tracer_frame;
+	int frame_size = READ_ONCE(tracer_frame);
+	int i, x;
+
+	this_size = ((unsigned long)stack) & (THREAD_SIZE-1);
+	this_size = THREAD_SIZE - this_size;
+	/* Remove the frame of the tracer */
+	this_size -= frame_size;
+
+	if (this_size <= stack_trace_max_size)
+		return;
+
+	/* we do not handle interrupt stacks yet */
+	if (!object_is_on_stack(stack))
+		return;
+
+	/* Can't do this from NMI context (can cause deadlocks) */
+	if (in_nmi())
+		return;
+
+	local_irq_save(flags);
+	arch_spin_lock(&stack_trace_max_lock);
+
+	/* In case another CPU set the tracer_frame on us */
+	if (unlikely(!frame_size))
+		this_size -= tracer_frame;
+
+	/* a race could have already updated it */
+	if (this_size <= stack_trace_max_size)
+		goto out;
+
+	stack_trace_max_size = this_size;
+
+	stack_trace_nr_entries = stack_trace_save(stack_dump_trace,
+					       ARRAY_SIZE(stack_dump_trace) - 1,
+					       0);
+
+	/* Skip over the overhead of the stack tracer itself */
+	for (i = 0; i < stack_trace_nr_entries; i++) {
+		if (stack_dump_trace[i] == ip)
+			break;
+	}
+
+	/*
+	 * Some archs may not have the passed in ip in the dump.
+	 * If that happens, we need to show everything.
+	 */
+	if (i == stack_trace_nr_entries)
+		i = 0;
+
+	/*
+	 * Now find where in the stack these are.
+	 */
+	x = 0;
+	start = stack;
+	top = (unsigned long *)
+		(((unsigned long)start & ~(THREAD_SIZE-1)) + THREAD_SIZE);
+
+	/*
+	 * Loop through all the entries. One of the entries may
+	 * for some reason be missed on the stack, so we may
+	 * have to account for them. If they are all there, this
+	 * loop will only happen once. This code only takes place
+	 * on a new max, so it is far from a fast path.
+	 */
+	while (i < stack_trace_nr_entries) {
+		int found = 0;
+
+		stack_trace_index[x] = this_size;
+		p = start;
+
+		for (; p < top && i < stack_trace_nr_entries; p++) {
+			/*
+			 * The READ_ONCE_NOCHECK is used to let KASAN know that
+			 * this is not a stack-out-of-bounds error.
+			 */
+			if ((READ_ONCE_NOCHECK(*p)) == stack_dump_trace[i]) {
+				stack_dump_trace[x] = stack_dump_trace[i++];
+				this_size = stack_trace_index[x++] =
+					(top - p) * sizeof(unsigned long);
+				found = 1;
+				/* Start the search from here */
+				start = p + 1;
+				/*
+				 * We do not want to show the overhead
+				 * of the stack tracer stack in the
+				 * max stack. If we haven't figured
+				 * out what that is, then figure it out
+				 * now.
+				 */
+				if (unlikely(!tracer_frame)) {
+					tracer_frame = (p - stack) *
+						sizeof(unsigned long);
+					stack_trace_max_size -= tracer_frame;
+				}
+			}
+		}
+
+		if (!found)
+			i++;
+	}
+
+#ifdef ARCH_FTRACE_SHIFT_STACK_TRACER
+	/*
+	 * Some archs will store the link register before calling
+	 * nested functions. This means the saved return address
+	 * comes after the local storage, and we need to shift
+	 * for that.
+	 */
+	if (x > 1) {
+		memmove(&stack_trace_index[0], &stack_trace_index[1],
+			sizeof(stack_trace_index[0]) * (x - 1));
+		x--;
+	}
+#endif
+
+	stack_trace_nr_entries = x;
+
+	if (task_stack_end_corrupted(current)) {
+		print_max_stack();
+		BUG();
+	}
+
+ out:
+	arch_spin_unlock(&stack_trace_max_lock);
+	local_irq_restore(flags);
+}
+
+/* Some archs may not define MCOUNT_INSN_SIZE */
+#ifndef MCOUNT_INSN_SIZE
+# define MCOUNT_INSN_SIZE 0
+#endif
+
+static void
+stack_trace_call(unsigned long ip, unsigned long parent_ip,
+		 struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	unsigned long stack;
+
+	preempt_disable_notrace();
+
+	/* no atomic needed, we only modify this variable by this cpu */
+	__this_cpu_inc(disable_stack_tracer);
+	if (__this_cpu_read(disable_stack_tracer) != 1)
+		goto out;
+
+	/* If rcu is not watching, then save stack trace can fail */
+	if (!rcu_is_watching())
+		goto out;
+
+	ip += MCOUNT_INSN_SIZE;
+
+	check_stack(ip, &stack);
+
+ out:
+	__this_cpu_dec(disable_stack_tracer);
+	/* prevent recursion in schedule */
+	preempt_enable_notrace();
+}
+
+static struct ftrace_ops trace_ops __read_mostly =
+{
+	.func = stack_trace_call,
+};
+
+static ssize_t
+stack_max_size_read(struct file *filp, char __user *ubuf,
+		    size_t count, loff_t *ppos)
+{
+	unsigned long *ptr = filp->private_data;
+	char buf[64];
+	int r;
+
+	r = snprintf(buf, sizeof(buf), "%ld\n", *ptr);
+	if (r > sizeof(buf))
+		r = sizeof(buf);
+	return simple_read_from_buffer(ubuf, count, ppos, buf, r);
+}
+
+static ssize_t
+stack_max_size_write(struct file *filp, const char __user *ubuf,
+		     size_t count, loff_t *ppos)
+{
+	long *ptr = filp->private_data;
+	unsigned long val, flags;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, count, 10, &val);
+	if (ret)
+		return ret;
+
+	local_irq_save(flags);
+
+	/*
+	 * In case we trace inside arch_spin_lock() or after (NMI),
+	 * we will cause circular lock, so we also need to increase
+	 * the percpu disable_stack_tracer here.
+	 */
+	__this_cpu_inc(disable_stack_tracer);
+
+	arch_spin_lock(&stack_trace_max_lock);
+	*ptr = val;
+	arch_spin_unlock(&stack_trace_max_lock);
+
+	__this_cpu_dec(disable_stack_tracer);
+	local_irq_restore(flags);
+
+	return count;
+}
+
+static const struct file_operations stack_max_size_fops = {
+	.open		= tracing_open_generic,
+	.read		= stack_max_size_read,
+	.write		= stack_max_size_write,
+	.llseek		= default_llseek,
+};
+
+static void *
+__next(struct seq_file *m, loff_t *pos)
+{
+	long n = *pos - 1;
+
+	if (n >= stack_trace_nr_entries)
+		return NULL;
+
+	m->private = (void *)n;
+	return &m->private;
+}
+
+static void *
+t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	(*pos)++;
+	return __next(m, pos);
+}
+
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+	local_irq_disable();
+
+	__this_cpu_inc(disable_stack_tracer);
+
+	arch_spin_lock(&stack_trace_max_lock);
+
+	if (*pos == 0)
+		return SEQ_START_TOKEN;
+
+	return __next(m, pos);
+}
+
+static void t_stop(struct seq_file *m, void *p)
+{
+	arch_spin_unlock(&stack_trace_max_lock);
+
+	__this_cpu_dec(disable_stack_tracer);
+
+	local_irq_enable();
+}
+
+static void trace_lookup_stack(struct seq_file *m, long i)
+{
+	unsigned long addr = stack_dump_trace[i];
+
+	seq_printf(m, "%pS\n", (void *)addr);
+}
+
+static void print_disabled(struct seq_file *m)
+{
+	seq_puts(m, "#\n"
+		 "#  Stack tracer disabled\n"
+		 "#\n"
+		 "# To enable the stack tracer, either add 'stacktrace' to the\n"
+		 "# kernel command line\n"
+		 "# or 'echo 1 > /proc/sys/kernel/stack_tracer_enabled'\n"
+		 "#\n");
+}
+
+static int t_show(struct seq_file *m, void *v)
+{
+	long i;
+	int size;
+
+	if (v == SEQ_START_TOKEN) {
+		seq_printf(m, "        Depth    Size   Location"
+			   "    (%d entries)\n"
+			   "        -----    ----   --------\n",
+			   stack_trace_nr_entries);
+
+		if (!stack_tracer_enabled && !stack_trace_max_size)
+			print_disabled(m);
+
+		return 0;
+	}
+
+	i = *(long *)v;
+
+	if (i >= stack_trace_nr_entries)
+		return 0;
+
+	if (i + 1 == stack_trace_nr_entries)
+		size = stack_trace_index[i];
+	else
+		size = stack_trace_index[i] - stack_trace_index[i+1];
+
+	seq_printf(m, "%3ld) %8d   %5d   ", i, stack_trace_index[i], size);
+
+	trace_lookup_stack(m, i);
+
+	return 0;
+}
+
+static const struct seq_operations stack_trace_seq_ops = {
+	.start		= t_start,
+	.next		= t_next,
+	.stop		= t_stop,
+	.show		= t_show,
+};
+
+static int stack_trace_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	return seq_open(file, &stack_trace_seq_ops);
+}
+
+static const struct file_operations stack_trace_fops = {
+	.open		= stack_trace_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+static int
+stack_trace_filter_open(struct inode *inode, struct file *file)
+{
+	struct ftrace_ops *ops = inode->i_private;
+
+	/* Checks for tracefs lockdown */
+	return ftrace_regex_open(ops, FTRACE_ITER_FILTER,
+				 inode, file);
+}
+
+static const struct file_operations stack_trace_filter_fops = {
+	.open = stack_trace_filter_open,
+	.read = seq_read,
+	.write = ftrace_filter_write,
+	.llseek = tracing_lseek,
+	.release = ftrace_regex_release,
+};
+
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+int
+stack_trace_sysctl(struct ctl_table *table, int write, void *buffer,
+		   size_t *lenp, loff_t *ppos)
+{
+	int was_enabled;
+	int ret;
+
+	mutex_lock(&stack_sysctl_mutex);
+	was_enabled = !!stack_tracer_enabled;
+
+	ret = proc_dointvec(table, write, buffer, lenp, ppos);
+
+	if (ret || !write || (was_enabled == !!stack_tracer_enabled))
+		goto out;
+
+	if (stack_tracer_enabled)
+		register_ftrace_function(&trace_ops);
+	else
+		unregister_ftrace_function(&trace_ops);
+ out:
+	mutex_unlock(&stack_sysctl_mutex);
+	return ret;
+}
+
+static char stack_trace_filter_buf[COMMAND_LINE_SIZE+1] __initdata;
+
+static __init int enable_stacktrace(char *str)
+{
+	int len;
+
+	if ((len = str_has_prefix(str, "_filter=")))
+		strncpy(stack_trace_filter_buf, str + len, COMMAND_LINE_SIZE);
+
+	stack_tracer_enabled = 1;
+	return 1;
+}
+__setup("stacktrace", enable_stacktrace);
+
+static __init int stack_trace_init(void)
+{
+	int ret;
+
+	ret = tracing_init_dentry();
+	if (ret)
+		return 0;
+
+	trace_create_file("stack_max_size", TRACE_MODE_WRITE, NULL,
+			&stack_trace_max_size, &stack_max_size_fops);
+
+	trace_create_file("stack_trace", TRACE_MODE_READ, NULL,
+			NULL, &stack_trace_fops);
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+	trace_create_file("stack_trace_filter", TRACE_MODE_WRITE, NULL,
+			  &trace_ops, &stack_trace_filter_fops);
+#endif
+
+	if (stack_trace_filter_buf[0])
+		ftrace_set_early_filter(&trace_ops, stack_trace_filter_buf, 1);
+
+	if (stack_tracer_enabled)
+		register_ftrace_function(&trace_ops);
+
+	return 0;
+}
+
+device_initcall(stack_trace_init);
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
new file mode 100644
index 000000000..bb247beec
--- /dev/null
+++ b/kernel/trace/trace_stat.c
@@ -0,0 +1,364 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Infrastructure for statistic tracing (histogram output).
+ *
+ * Copyright (C) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
+ *
+ * Based on the code from trace_branch.c which is
+ * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
+ *
+ */
+
+#include <linux/security.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/rbtree.h>
+#include <linux/tracefs.h>
+#include "trace_stat.h"
+#include "trace.h"
+
+
+/*
+ * List of stat red-black nodes from a tracer
+ * We use a such tree to sort quickly the stat
+ * entries from the tracer.
+ */
+struct stat_node {
+	struct rb_node		node;
+	void			*stat;
+};
+
+/* A stat session is the stats output in one file */
+struct stat_session {
+	struct list_head	session_list;
+	struct tracer_stat	*ts;
+	struct rb_root		stat_root;
+	struct mutex		stat_mutex;
+	struct dentry		*file;
+};
+
+/* All of the sessions currently in use. Each stat file embed one session */
+static LIST_HEAD(all_stat_sessions);
+static DEFINE_MUTEX(all_stat_sessions_mutex);
+
+/* The root directory for all stat files */
+static struct dentry		*stat_dir;
+
+static void __reset_stat_session(struct stat_session *session)
+{
+	struct stat_node *snode, *n;
+
+	rbtree_postorder_for_each_entry_safe(snode, n, &session->stat_root, node) {
+		if (session->ts->stat_release)
+			session->ts->stat_release(snode->stat);
+		kfree(snode);
+	}
+
+	session->stat_root = RB_ROOT;
+}
+
+static void reset_stat_session(struct stat_session *session)
+{
+	mutex_lock(&session->stat_mutex);
+	__reset_stat_session(session);
+	mutex_unlock(&session->stat_mutex);
+}
+
+static void destroy_session(struct stat_session *session)
+{
+	tracefs_remove(session->file);
+	__reset_stat_session(session);
+	mutex_destroy(&session->stat_mutex);
+	kfree(session);
+}
+
+static int insert_stat(struct rb_root *root, void *stat, cmp_func_t cmp)
+{
+	struct rb_node **new = &(root->rb_node), *parent = NULL;
+	struct stat_node *data;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	data->stat = stat;
+
+	/*
+	 * Figure out where to put new node
+	 * This is a descendent sorting
+	 */
+	while (*new) {
+		struct stat_node *this;
+		int result;
+
+		this = container_of(*new, struct stat_node, node);
+		result = cmp(data->stat, this->stat);
+
+		parent = *new;
+		if (result >= 0)
+			new = &((*new)->rb_left);
+		else
+			new = &((*new)->rb_right);
+	}
+
+	rb_link_node(&data->node, parent, new);
+	rb_insert_color(&data->node, root);
+	return 0;
+}
+
+/*
+ * For tracers that don't provide a stat_cmp callback.
+ * This one will force an insertion as right-most node
+ * in the rbtree.
+ */
+static int dummy_cmp(const void *p1, const void *p2)
+{
+	return -1;
+}
+
+/*
+ * Initialize the stat rbtree at each trace_stat file opening.
+ * All of these copies and sorting are required on all opening
+ * since the stats could have changed between two file sessions.
+ */
+static int stat_seq_init(struct stat_session *session)
+{
+	struct tracer_stat *ts = session->ts;
+	struct rb_root *root = &session->stat_root;
+	void *stat;
+	int ret = 0;
+	int i;
+
+	mutex_lock(&session->stat_mutex);
+	__reset_stat_session(session);
+
+	if (!ts->stat_cmp)
+		ts->stat_cmp = dummy_cmp;
+
+	stat = ts->stat_start(ts);
+	if (!stat)
+		goto exit;
+
+	ret = insert_stat(root, stat, ts->stat_cmp);
+	if (ret)
+		goto exit;
+
+	/*
+	 * Iterate over the tracer stat entries and store them in an rbtree.
+	 */
+	for (i = 1; ; i++) {
+		stat = ts->stat_next(stat, i);
+
+		/* End of insertion */
+		if (!stat)
+			break;
+
+		ret = insert_stat(root, stat, ts->stat_cmp);
+		if (ret)
+			goto exit_free_rbtree;
+	}
+
+exit:
+	mutex_unlock(&session->stat_mutex);
+	return ret;
+
+exit_free_rbtree:
+	__reset_stat_session(session);
+	mutex_unlock(&session->stat_mutex);
+	return ret;
+}
+
+
+static void *stat_seq_start(struct seq_file *s, loff_t *pos)
+{
+	struct stat_session *session = s->private;
+	struct rb_node *node;
+	int n = *pos;
+	int i;
+
+	/* Prevent from tracer switch or rbtree modification */
+	mutex_lock(&session->stat_mutex);
+
+	/* If we are in the beginning of the file, print the headers */
+	if (session->ts->stat_headers) {
+		if (n == 0)
+			return SEQ_START_TOKEN;
+		n--;
+	}
+
+	node = rb_first(&session->stat_root);
+	for (i = 0; node && i < n; i++)
+		node = rb_next(node);
+
+	return node;
+}
+
+static void *stat_seq_next(struct seq_file *s, void *p, loff_t *pos)
+{
+	struct stat_session *session = s->private;
+	struct rb_node *node = p;
+
+	(*pos)++;
+
+	if (p == SEQ_START_TOKEN)
+		return rb_first(&session->stat_root);
+
+	return rb_next(node);
+}
+
+static void stat_seq_stop(struct seq_file *s, void *p)
+{
+	struct stat_session *session = s->private;
+	mutex_unlock(&session->stat_mutex);
+}
+
+static int stat_seq_show(struct seq_file *s, void *v)
+{
+	struct stat_session *session = s->private;
+	struct stat_node *l = container_of(v, struct stat_node, node);
+
+	if (v == SEQ_START_TOKEN)
+		return session->ts->stat_headers(s);
+
+	return session->ts->stat_show(s, l->stat);
+}
+
+static const struct seq_operations trace_stat_seq_ops = {
+	.start		= stat_seq_start,
+	.next		= stat_seq_next,
+	.stop		= stat_seq_stop,
+	.show		= stat_seq_show
+};
+
+/* The session stat is refilled and resorted at each stat file opening */
+static int tracing_stat_open(struct inode *inode, struct file *file)
+{
+	int ret;
+	struct seq_file *m;
+	struct stat_session *session = inode->i_private;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	ret = stat_seq_init(session);
+	if (ret)
+		return ret;
+
+	ret = seq_open(file, &trace_stat_seq_ops);
+	if (ret) {
+		reset_stat_session(session);
+		return ret;
+	}
+
+	m = file->private_data;
+	m->private = session;
+	return ret;
+}
+
+/*
+ * Avoid consuming memory with our now useless rbtree.
+ */
+static int tracing_stat_release(struct inode *i, struct file *f)
+{
+	struct stat_session *session = i->i_private;
+
+	reset_stat_session(session);
+
+	return seq_release(i, f);
+}
+
+static const struct file_operations tracing_stat_fops = {
+	.open		= tracing_stat_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= tracing_stat_release
+};
+
+static int tracing_stat_init(void)
+{
+	int ret;
+
+	ret = tracing_init_dentry();
+	if (ret)
+		return -ENODEV;
+
+	stat_dir = tracefs_create_dir("trace_stat", NULL);
+	if (!stat_dir) {
+		pr_warn("Could not create tracefs 'trace_stat' entry\n");
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+static int init_stat_file(struct stat_session *session)
+{
+	int ret;
+
+	if (!stat_dir && (ret = tracing_stat_init()))
+		return ret;
+
+	session->file = tracefs_create_file(session->ts->name, TRACE_MODE_WRITE,
+					    stat_dir, session,
+					    &tracing_stat_fops);
+	if (!session->file)
+		return -ENOMEM;
+	return 0;
+}
+
+int register_stat_tracer(struct tracer_stat *trace)
+{
+	struct stat_session *session, *node;
+	int ret = -EINVAL;
+
+	if (!trace)
+		return -EINVAL;
+
+	if (!trace->stat_start || !trace->stat_next || !trace->stat_show)
+		return -EINVAL;
+
+	/* Already registered? */
+	mutex_lock(&all_stat_sessions_mutex);
+	list_for_each_entry(node, &all_stat_sessions, session_list) {
+		if (node->ts == trace)
+			goto out;
+	}
+
+	ret = -ENOMEM;
+	/* Init the session */
+	session = kzalloc(sizeof(*session), GFP_KERNEL);
+	if (!session)
+		goto out;
+
+	session->ts = trace;
+	INIT_LIST_HEAD(&session->session_list);
+	mutex_init(&session->stat_mutex);
+
+	ret = init_stat_file(session);
+	if (ret) {
+		destroy_session(session);
+		goto out;
+	}
+
+	ret = 0;
+	/* Register */
+	list_add_tail(&session->session_list, &all_stat_sessions);
+ out:
+	mutex_unlock(&all_stat_sessions_mutex);
+
+	return ret;
+}
+
+void unregister_stat_tracer(struct tracer_stat *trace)
+{
+	struct stat_session *node, *tmp;
+
+	mutex_lock(&all_stat_sessions_mutex);
+	list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) {
+		if (node->ts == trace) {
+			list_del(&node->session_list);
+			destroy_session(node);
+			break;
+		}
+	}
+	mutex_unlock(&all_stat_sessions_mutex);
+}
diff --git a/kernel/trace/trace_stat.h b/kernel/trace/trace_stat.h
new file mode 100644
index 000000000..31d7dc5bf
--- /dev/null
+++ b/kernel/trace/trace_stat.h
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef __TRACE_STAT_H
+#define __TRACE_STAT_H
+
+#include <linux/seq_file.h>
+
+/*
+ * If you want to provide a stat file (one-shot statistics), fill
+ * an iterator with stat_start/stat_next and a stat_show callbacks.
+ * The others callbacks are optional.
+ */
+struct tracer_stat {
+	/* The name of your stat file */
+	const char		*name;
+	/* Iteration over statistic entries */
+	void			*(*stat_start)(struct tracer_stat *trace);
+	void			*(*stat_next)(void *prev, int idx);
+	/* Compare two entries for stats sorting */
+	cmp_func_t		stat_cmp;
+	/* Print a stat entry */
+	int			(*stat_show)(struct seq_file *s, void *p);
+	/* Release an entry */
+	void			(*stat_release)(void *stat);
+	/* Print the headers of your stat entries */
+	int			(*stat_headers)(struct seq_file *s);
+};
+
+/*
+ * Destroy or create a stat file
+ */
+extern int register_stat_tracer(struct tracer_stat *trace);
+extern void unregister_stat_tracer(struct tracer_stat *trace);
+
+#endif /* __TRACE_STAT_H */
diff --git a/kernel/trace/trace_synth.h b/kernel/trace/trace_synth.h
new file mode 100644
index 000000000..43f6fb607
--- /dev/null
+++ b/kernel/trace/trace_synth.h
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef __TRACE_SYNTH_H
+#define __TRACE_SYNTH_H
+
+#include "trace_dynevent.h"
+
+#define SYNTH_SYSTEM		"synthetic"
+#define SYNTH_FIELDS_MAX	64
+
+#define STR_VAR_LEN_MAX		MAX_FILTER_STR_VAL /* must be multiple of sizeof(u64) */
+
+struct synth_field {
+	char *type;
+	char *name;
+	size_t size;
+	unsigned int offset;
+	unsigned int field_pos;
+	bool is_signed;
+	bool is_string;
+	bool is_dynamic;
+	bool is_stack;
+};
+
+struct synth_event {
+	struct dyn_event			devent;
+	int					ref;
+	char					*name;
+	struct synth_field			**fields;
+	unsigned int				n_fields;
+	struct synth_field			**dynamic_fields;
+	unsigned int				n_dynamic_fields;
+	unsigned int				n_u64;
+	struct trace_event_class		class;
+	struct trace_event_call			call;
+	struct tracepoint			*tp;
+	struct module				*mod;
+};
+
+extern struct synth_event *find_synth_event(const char *name);
+
+#endif /* __TRACE_SYNTH_H */
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
new file mode 100644
index 000000000..942ddbdac
--- /dev/null
+++ b/kernel/trace/trace_syscalls.c
@@ -0,0 +1,808 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <trace/syscall.h>
+#include <trace/events/syscalls.h>
+#include <linux/syscalls.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/module.h>	/* for MODULE_NAME_LEN via KSYM_SYMBOL_LEN */
+#include <linux/ftrace.h>
+#include <linux/perf_event.h>
+#include <linux/xarray.h>
+#include <asm/syscall.h>
+
+#include "trace_output.h"
+#include "trace.h"
+
+static DEFINE_MUTEX(syscall_trace_lock);
+
+static int syscall_enter_register(struct trace_event_call *event,
+				 enum trace_reg type, void *data);
+static int syscall_exit_register(struct trace_event_call *event,
+				 enum trace_reg type, void *data);
+
+static struct list_head *
+syscall_get_enter_fields(struct trace_event_call *call)
+{
+	struct syscall_metadata *entry = call->data;
+
+	return &entry->enter_fields;
+}
+
+extern struct syscall_metadata *__start_syscalls_metadata[];
+extern struct syscall_metadata *__stop_syscalls_metadata[];
+
+static DEFINE_XARRAY(syscalls_metadata_sparse);
+static struct syscall_metadata **syscalls_metadata;
+
+#ifndef ARCH_HAS_SYSCALL_MATCH_SYM_NAME
+static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)
+{
+	/*
+	 * Only compare after the "sys" prefix. Archs that use
+	 * syscall wrappers may have syscalls symbols aliases prefixed
+	 * with ".SyS" or ".sys" instead of "sys", leading to an unwanted
+	 * mismatch.
+	 */
+	return !strcmp(sym + 3, name + 3);
+}
+#endif
+
+#ifdef ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
+/*
+ * Some architectures that allow for 32bit applications
+ * to run on a 64bit kernel, do not map the syscalls for
+ * the 32bit tasks the same as they do for 64bit tasks.
+ *
+ *     *cough*x86*cough*
+ *
+ * In such a case, instead of reporting the wrong syscalls,
+ * simply ignore them.
+ *
+ * For an arch to ignore the compat syscalls it needs to
+ * define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS as well as
+ * define the function arch_trace_is_compat_syscall() to let
+ * the tracing system know that it should ignore it.
+ */
+static int
+trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
+{
+	if (unlikely(arch_trace_is_compat_syscall(regs)))
+		return -1;
+
+	return syscall_get_nr(task, regs);
+}
+#else
+static inline int
+trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
+{
+	return syscall_get_nr(task, regs);
+}
+#endif /* ARCH_TRACE_IGNORE_COMPAT_SYSCALLS */
+
+static __init struct syscall_metadata *
+find_syscall_meta(unsigned long syscall)
+{
+	struct syscall_metadata **start;
+	struct syscall_metadata **stop;
+	char str[KSYM_SYMBOL_LEN];
+
+
+	start = __start_syscalls_metadata;
+	stop = __stop_syscalls_metadata;
+	kallsyms_lookup(syscall, NULL, NULL, NULL, str);
+
+	if (arch_syscall_match_sym_name(str, "sys_ni_syscall"))
+		return NULL;
+
+	for ( ; start < stop; start++) {
+		if ((*start)->name && arch_syscall_match_sym_name(str, (*start)->name))
+			return *start;
+	}
+	return NULL;
+}
+
+static struct syscall_metadata *syscall_nr_to_meta(int nr)
+{
+	if (IS_ENABLED(CONFIG_HAVE_SPARSE_SYSCALL_NR))
+		return xa_load(&syscalls_metadata_sparse, (unsigned long)nr);
+
+	if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
+		return NULL;
+
+	return syscalls_metadata[nr];
+}
+
+const char *get_syscall_name(int syscall)
+{
+	struct syscall_metadata *entry;
+
+	entry = syscall_nr_to_meta(syscall);
+	if (!entry)
+		return NULL;
+
+	return entry->name;
+}
+
+static enum print_line_t
+print_syscall_enter(struct trace_iterator *iter, int flags,
+		    struct trace_event *event)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *ent = iter->ent;
+	struct syscall_trace_enter *trace;
+	struct syscall_metadata *entry;
+	int i, syscall;
+
+	trace = (typeof(trace))ent;
+	syscall = trace->nr;
+	entry = syscall_nr_to_meta(syscall);
+
+	if (!entry)
+		goto end;
+
+	if (entry->enter_event->event.type != ent->type) {
+		WARN_ON_ONCE(1);
+		goto end;
+	}
+
+	trace_seq_printf(s, "%s(", entry->name);
+
+	for (i = 0; i < entry->nb_args; i++) {
+
+		if (trace_seq_has_overflowed(s))
+			goto end;
+
+		/* parameter types */
+		if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
+			trace_seq_printf(s, "%s ", entry->types[i]);
+
+		/* parameter values */
+		trace_seq_printf(s, "%s: %lx%s", entry->args[i],
+				 trace->args[i],
+				 i == entry->nb_args - 1 ? "" : ", ");
+	}
+
+	trace_seq_putc(s, ')');
+end:
+	trace_seq_putc(s, '\n');
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t
+print_syscall_exit(struct trace_iterator *iter, int flags,
+		   struct trace_event *event)
+{
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *ent = iter->ent;
+	struct syscall_trace_exit *trace;
+	int syscall;
+	struct syscall_metadata *entry;
+
+	trace = (typeof(trace))ent;
+	syscall = trace->nr;
+	entry = syscall_nr_to_meta(syscall);
+
+	if (!entry) {
+		trace_seq_putc(s, '\n');
+		goto out;
+	}
+
+	if (entry->exit_event->event.type != ent->type) {
+		WARN_ON_ONCE(1);
+		return TRACE_TYPE_UNHANDLED;
+	}
+
+	trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
+				trace->ret);
+
+ out:
+	return trace_handle_return(s);
+}
+
+#define SYSCALL_FIELD(_type, _name) {					\
+	.type = #_type, .name = #_name,					\
+	.size = sizeof(_type), .align = __alignof__(_type),		\
+	.is_signed = is_signed_type(_type), .filter_type = FILTER_OTHER }
+
+static int __init
+__set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
+{
+	int i;
+	int pos = 0;
+
+	/* When len=0, we just calculate the needed length */
+#define LEN_OR_ZERO (len ? len - pos : 0)
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
+	for (i = 0; i < entry->nb_args; i++) {
+		pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
+				entry->args[i], sizeof(unsigned long),
+				i == entry->nb_args - 1 ? "" : ", ");
+	}
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
+
+	for (i = 0; i < entry->nb_args; i++) {
+		pos += snprintf(buf + pos, LEN_OR_ZERO,
+				", ((unsigned long)(REC->%s))", entry->args[i]);
+	}
+
+#undef LEN_OR_ZERO
+
+	/* return the length of print_fmt */
+	return pos;
+}
+
+static int __init set_syscall_print_fmt(struct trace_event_call *call)
+{
+	char *print_fmt;
+	int len;
+	struct syscall_metadata *entry = call->data;
+
+	if (entry->enter_event != call) {
+		call->print_fmt = "\"0x%lx\", REC->ret";
+		return 0;
+	}
+
+	/* First: called with 0 length to calculate the needed length */
+	len = __set_enter_print_fmt(entry, NULL, 0);
+
+	print_fmt = kmalloc(len + 1, GFP_KERNEL);
+	if (!print_fmt)
+		return -ENOMEM;
+
+	/* Second: actually write the @print_fmt */
+	__set_enter_print_fmt(entry, print_fmt, len + 1);
+	call->print_fmt = print_fmt;
+
+	return 0;
+}
+
+static void __init free_syscall_print_fmt(struct trace_event_call *call)
+{
+	struct syscall_metadata *entry = call->data;
+
+	if (entry->enter_event == call)
+		kfree(call->print_fmt);
+}
+
+static int __init syscall_enter_define_fields(struct trace_event_call *call)
+{
+	struct syscall_trace_enter trace;
+	struct syscall_metadata *meta = call->data;
+	int offset = offsetof(typeof(trace), args);
+	int ret = 0;
+	int i;
+
+	for (i = 0; i < meta->nb_args; i++) {
+		ret = trace_define_field(call, meta->types[i],
+					 meta->args[i], offset,
+					 sizeof(unsigned long), 0,
+					 FILTER_OTHER);
+		if (ret)
+			break;
+		offset += sizeof(unsigned long);
+	}
+
+	return ret;
+}
+
+static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
+{
+	struct trace_array *tr = data;
+	struct trace_event_file *trace_file;
+	struct syscall_trace_enter *entry;
+	struct syscall_metadata *sys_data;
+	struct trace_event_buffer fbuffer;
+	unsigned long args[6];
+	int syscall_nr;
+	int size;
+
+	syscall_nr = trace_get_syscall_nr(current, regs);
+	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
+		return;
+
+	/* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */
+	trace_file = rcu_dereference_sched(tr->enter_syscall_files[syscall_nr]);
+	if (!trace_file)
+		return;
+
+	if (trace_trigger_soft_disabled(trace_file))
+		return;
+
+	sys_data = syscall_nr_to_meta(syscall_nr);
+	if (!sys_data)
+		return;
+
+	size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
+
+	entry = trace_event_buffer_reserve(&fbuffer, trace_file, size);
+	if (!entry)
+		return;
+
+	entry = ring_buffer_event_data(fbuffer.event);
+	entry->nr = syscall_nr;
+	syscall_get_arguments(current, regs, args);
+	memcpy(entry->args, args, sizeof(unsigned long) * sys_data->nb_args);
+
+	trace_event_buffer_commit(&fbuffer);
+}
+
+static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
+{
+	struct trace_array *tr = data;
+	struct trace_event_file *trace_file;
+	struct syscall_trace_exit *entry;
+	struct syscall_metadata *sys_data;
+	struct trace_event_buffer fbuffer;
+	int syscall_nr;
+
+	syscall_nr = trace_get_syscall_nr(current, regs);
+	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
+		return;
+
+	/* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */
+	trace_file = rcu_dereference_sched(tr->exit_syscall_files[syscall_nr]);
+	if (!trace_file)
+		return;
+
+	if (trace_trigger_soft_disabled(trace_file))
+		return;
+
+	sys_data = syscall_nr_to_meta(syscall_nr);
+	if (!sys_data)
+		return;
+
+	entry = trace_event_buffer_reserve(&fbuffer, trace_file, sizeof(*entry));
+	if (!entry)
+		return;
+
+	entry = ring_buffer_event_data(fbuffer.event);
+	entry->nr = syscall_nr;
+	entry->ret = syscall_get_return_value(current, regs);
+
+	trace_event_buffer_commit(&fbuffer);
+}
+
+static int reg_event_syscall_enter(struct trace_event_file *file,
+				   struct trace_event_call *call)
+{
+	struct trace_array *tr = file->tr;
+	int ret = 0;
+	int num;
+
+	num = ((struct syscall_metadata *)call->data)->syscall_nr;
+	if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
+		return -ENOSYS;
+	mutex_lock(&syscall_trace_lock);
+	if (!tr->sys_refcount_enter)
+		ret = register_trace_sys_enter(ftrace_syscall_enter, tr);
+	if (!ret) {
+		rcu_assign_pointer(tr->enter_syscall_files[num], file);
+		tr->sys_refcount_enter++;
+	}
+	mutex_unlock(&syscall_trace_lock);
+	return ret;
+}
+
+static void unreg_event_syscall_enter(struct trace_event_file *file,
+				      struct trace_event_call *call)
+{
+	struct trace_array *tr = file->tr;
+	int num;
+
+	num = ((struct syscall_metadata *)call->data)->syscall_nr;
+	if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
+		return;
+	mutex_lock(&syscall_trace_lock);
+	tr->sys_refcount_enter--;
+	RCU_INIT_POINTER(tr->enter_syscall_files[num], NULL);
+	if (!tr->sys_refcount_enter)
+		unregister_trace_sys_enter(ftrace_syscall_enter, tr);
+	mutex_unlock(&syscall_trace_lock);
+}
+
+static int reg_event_syscall_exit(struct trace_event_file *file,
+				  struct trace_event_call *call)
+{
+	struct trace_array *tr = file->tr;
+	int ret = 0;
+	int num;
+
+	num = ((struct syscall_metadata *)call->data)->syscall_nr;
+	if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
+		return -ENOSYS;
+	mutex_lock(&syscall_trace_lock);
+	if (!tr->sys_refcount_exit)
+		ret = register_trace_sys_exit(ftrace_syscall_exit, tr);
+	if (!ret) {
+		rcu_assign_pointer(tr->exit_syscall_files[num], file);
+		tr->sys_refcount_exit++;
+	}
+	mutex_unlock(&syscall_trace_lock);
+	return ret;
+}
+
+static void unreg_event_syscall_exit(struct trace_event_file *file,
+				     struct trace_event_call *call)
+{
+	struct trace_array *tr = file->tr;
+	int num;
+
+	num = ((struct syscall_metadata *)call->data)->syscall_nr;
+	if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
+		return;
+	mutex_lock(&syscall_trace_lock);
+	tr->sys_refcount_exit--;
+	RCU_INIT_POINTER(tr->exit_syscall_files[num], NULL);
+	if (!tr->sys_refcount_exit)
+		unregister_trace_sys_exit(ftrace_syscall_exit, tr);
+	mutex_unlock(&syscall_trace_lock);
+}
+
+static int __init init_syscall_trace(struct trace_event_call *call)
+{
+	int id;
+	int num;
+
+	num = ((struct syscall_metadata *)call->data)->syscall_nr;
+	if (num < 0 || num >= NR_syscalls) {
+		pr_debug("syscall %s metadata not mapped, disabling ftrace event\n",
+				((struct syscall_metadata *)call->data)->name);
+		return -ENOSYS;
+	}
+
+	if (set_syscall_print_fmt(call) < 0)
+		return -ENOMEM;
+
+	id = trace_event_raw_init(call);
+
+	if (id < 0) {
+		free_syscall_print_fmt(call);
+		return id;
+	}
+
+	return id;
+}
+
+static struct trace_event_fields __refdata syscall_enter_fields_array[] = {
+	SYSCALL_FIELD(int, __syscall_nr),
+	{ .type = TRACE_FUNCTION_TYPE,
+	  .define_fields = syscall_enter_define_fields },
+	{}
+};
+
+struct trace_event_functions enter_syscall_print_funcs = {
+	.trace		= print_syscall_enter,
+};
+
+struct trace_event_functions exit_syscall_print_funcs = {
+	.trace		= print_syscall_exit,
+};
+
+struct trace_event_class __refdata event_class_syscall_enter = {
+	.system		= "syscalls",
+	.reg		= syscall_enter_register,
+	.fields_array	= syscall_enter_fields_array,
+	.get_fields	= syscall_get_enter_fields,
+	.raw_init	= init_syscall_trace,
+};
+
+struct trace_event_class __refdata event_class_syscall_exit = {
+	.system		= "syscalls",
+	.reg		= syscall_exit_register,
+	.fields_array	= (struct trace_event_fields[]){
+		SYSCALL_FIELD(int, __syscall_nr),
+		SYSCALL_FIELD(long, ret),
+		{}
+	},
+	.fields		= LIST_HEAD_INIT(event_class_syscall_exit.fields),
+	.raw_init	= init_syscall_trace,
+};
+
+unsigned long __init __weak arch_syscall_addr(int nr)
+{
+	return (unsigned long)sys_call_table[nr];
+}
+
+void __init init_ftrace_syscalls(void)
+{
+	struct syscall_metadata *meta;
+	unsigned long addr;
+	int i;
+	void *ret;
+
+	if (!IS_ENABLED(CONFIG_HAVE_SPARSE_SYSCALL_NR)) {
+		syscalls_metadata = kcalloc(NR_syscalls,
+					sizeof(*syscalls_metadata),
+					GFP_KERNEL);
+		if (!syscalls_metadata) {
+			WARN_ON(1);
+			return;
+		}
+	}
+
+	for (i = 0; i < NR_syscalls; i++) {
+		addr = arch_syscall_addr(i);
+		meta = find_syscall_meta(addr);
+		if (!meta)
+			continue;
+
+		meta->syscall_nr = i;
+
+		if (!IS_ENABLED(CONFIG_HAVE_SPARSE_SYSCALL_NR)) {
+			syscalls_metadata[i] = meta;
+		} else {
+			ret = xa_store(&syscalls_metadata_sparse, i, meta,
+					GFP_KERNEL);
+			WARN(xa_is_err(ret),
+				"Syscall memory allocation failed\n");
+		}
+
+	}
+}
+
+#ifdef CONFIG_PERF_EVENTS
+
+static DECLARE_BITMAP(enabled_perf_enter_syscalls, NR_syscalls);
+static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls);
+static int sys_perf_refcount_enter;
+static int sys_perf_refcount_exit;
+
+static int perf_call_bpf_enter(struct trace_event_call *call, struct pt_regs *regs,
+			       struct syscall_metadata *sys_data,
+			       struct syscall_trace_enter *rec)
+{
+	struct syscall_tp_t {
+		unsigned long long regs;
+		unsigned long syscall_nr;
+		unsigned long args[SYSCALL_DEFINE_MAXARGS];
+	} param;
+	int i;
+
+	*(struct pt_regs **)&param = regs;
+	param.syscall_nr = rec->nr;
+	for (i = 0; i < sys_data->nb_args; i++)
+		param.args[i] = rec->args[i];
+	return trace_call_bpf(call, &param);
+}
+
+static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
+{
+	struct syscall_metadata *sys_data;
+	struct syscall_trace_enter *rec;
+	struct hlist_head *head;
+	unsigned long args[6];
+	bool valid_prog_array;
+	int syscall_nr;
+	int rctx;
+	int size;
+
+	syscall_nr = trace_get_syscall_nr(current, regs);
+	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
+		return;
+	if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
+		return;
+
+	sys_data = syscall_nr_to_meta(syscall_nr);
+	if (!sys_data)
+		return;
+
+	head = this_cpu_ptr(sys_data->enter_event->perf_events);
+	valid_prog_array = bpf_prog_array_valid(sys_data->enter_event);
+	if (!valid_prog_array && hlist_empty(head))
+		return;
+
+	/* get the size after alignment with the u32 buffer size field */
+	size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
+	size = ALIGN(size + sizeof(u32), sizeof(u64));
+	size -= sizeof(u32);
+
+	rec = perf_trace_buf_alloc(size, NULL, &rctx);
+	if (!rec)
+		return;
+
+	rec->nr = syscall_nr;
+	syscall_get_arguments(current, regs, args);
+	memcpy(&rec->args, args, sizeof(unsigned long) * sys_data->nb_args);
+
+	if ((valid_prog_array &&
+	     !perf_call_bpf_enter(sys_data->enter_event, regs, sys_data, rec)) ||
+	    hlist_empty(head)) {
+		perf_swevent_put_recursion_context(rctx);
+		return;
+	}
+
+	perf_trace_buf_submit(rec, size, rctx,
+			      sys_data->enter_event->event.type, 1, regs,
+			      head, NULL);
+}
+
+static int perf_sysenter_enable(struct trace_event_call *call)
+{
+	int ret = 0;
+	int num;
+
+	num = ((struct syscall_metadata *)call->data)->syscall_nr;
+
+	mutex_lock(&syscall_trace_lock);
+	if (!sys_perf_refcount_enter)
+		ret = register_trace_sys_enter(perf_syscall_enter, NULL);
+	if (ret) {
+		pr_info("event trace: Could not activate syscall entry trace point");
+	} else {
+		set_bit(num, enabled_perf_enter_syscalls);
+		sys_perf_refcount_enter++;
+	}
+	mutex_unlock(&syscall_trace_lock);
+	return ret;
+}
+
+static void perf_sysenter_disable(struct trace_event_call *call)
+{
+	int num;
+
+	num = ((struct syscall_metadata *)call->data)->syscall_nr;
+
+	mutex_lock(&syscall_trace_lock);
+	sys_perf_refcount_enter--;
+	clear_bit(num, enabled_perf_enter_syscalls);
+	if (!sys_perf_refcount_enter)
+		unregister_trace_sys_enter(perf_syscall_enter, NULL);
+	mutex_unlock(&syscall_trace_lock);
+}
+
+static int perf_call_bpf_exit(struct trace_event_call *call, struct pt_regs *regs,
+			      struct syscall_trace_exit *rec)
+{
+	struct syscall_tp_t {
+		unsigned long long regs;
+		unsigned long syscall_nr;
+		unsigned long ret;
+	} param;
+
+	*(struct pt_regs **)&param = regs;
+	param.syscall_nr = rec->nr;
+	param.ret = rec->ret;
+	return trace_call_bpf(call, &param);
+}
+
+static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
+{
+	struct syscall_metadata *sys_data;
+	struct syscall_trace_exit *rec;
+	struct hlist_head *head;
+	bool valid_prog_array;
+	int syscall_nr;
+	int rctx;
+	int size;
+
+	syscall_nr = trace_get_syscall_nr(current, regs);
+	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
+		return;
+	if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
+		return;
+
+	sys_data = syscall_nr_to_meta(syscall_nr);
+	if (!sys_data)
+		return;
+
+	head = this_cpu_ptr(sys_data->exit_event->perf_events);
+	valid_prog_array = bpf_prog_array_valid(sys_data->exit_event);
+	if (!valid_prog_array && hlist_empty(head))
+		return;
+
+	/* We can probably do that at build time */
+	size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
+	size -= sizeof(u32);
+
+	rec = perf_trace_buf_alloc(size, NULL, &rctx);
+	if (!rec)
+		return;
+
+	rec->nr = syscall_nr;
+	rec->ret = syscall_get_return_value(current, regs);
+
+	if ((valid_prog_array &&
+	     !perf_call_bpf_exit(sys_data->exit_event, regs, rec)) ||
+	    hlist_empty(head)) {
+		perf_swevent_put_recursion_context(rctx);
+		return;
+	}
+
+	perf_trace_buf_submit(rec, size, rctx, sys_data->exit_event->event.type,
+			      1, regs, head, NULL);
+}
+
+static int perf_sysexit_enable(struct trace_event_call *call)
+{
+	int ret = 0;
+	int num;
+
+	num = ((struct syscall_metadata *)call->data)->syscall_nr;
+
+	mutex_lock(&syscall_trace_lock);
+	if (!sys_perf_refcount_exit)
+		ret = register_trace_sys_exit(perf_syscall_exit, NULL);
+	if (ret) {
+		pr_info("event trace: Could not activate syscall exit trace point");
+	} else {
+		set_bit(num, enabled_perf_exit_syscalls);
+		sys_perf_refcount_exit++;
+	}
+	mutex_unlock(&syscall_trace_lock);
+	return ret;
+}
+
+static void perf_sysexit_disable(struct trace_event_call *call)
+{
+	int num;
+
+	num = ((struct syscall_metadata *)call->data)->syscall_nr;
+
+	mutex_lock(&syscall_trace_lock);
+	sys_perf_refcount_exit--;
+	clear_bit(num, enabled_perf_exit_syscalls);
+	if (!sys_perf_refcount_exit)
+		unregister_trace_sys_exit(perf_syscall_exit, NULL);
+	mutex_unlock(&syscall_trace_lock);
+}
+
+#endif /* CONFIG_PERF_EVENTS */
+
+static int syscall_enter_register(struct trace_event_call *event,
+				 enum trace_reg type, void *data)
+{
+	struct trace_event_file *file = data;
+
+	switch (type) {
+	case TRACE_REG_REGISTER:
+		return reg_event_syscall_enter(file, event);
+	case TRACE_REG_UNREGISTER:
+		unreg_event_syscall_enter(file, event);
+		return 0;
+
+#ifdef CONFIG_PERF_EVENTS
+	case TRACE_REG_PERF_REGISTER:
+		return perf_sysenter_enable(event);
+	case TRACE_REG_PERF_UNREGISTER:
+		perf_sysenter_disable(event);
+		return 0;
+	case TRACE_REG_PERF_OPEN:
+	case TRACE_REG_PERF_CLOSE:
+	case TRACE_REG_PERF_ADD:
+	case TRACE_REG_PERF_DEL:
+		return 0;
+#endif
+	}
+	return 0;
+}
+
+static int syscall_exit_register(struct trace_event_call *event,
+				 enum trace_reg type, void *data)
+{
+	struct trace_event_file *file = data;
+
+	switch (type) {
+	case TRACE_REG_REGISTER:
+		return reg_event_syscall_exit(file, event);
+	case TRACE_REG_UNREGISTER:
+		unreg_event_syscall_exit(file, event);
+		return 0;
+
+#ifdef CONFIG_PERF_EVENTS
+	case TRACE_REG_PERF_REGISTER:
+		return perf_sysexit_enable(event);
+	case TRACE_REG_PERF_UNREGISTER:
+		perf_sysexit_disable(event);
+		return 0;
+	case TRACE_REG_PERF_OPEN:
+	case TRACE_REG_PERF_CLOSE:
+	case TRACE_REG_PERF_ADD:
+	case TRACE_REG_PERF_DEL:
+		return 0;
+#endif
+	}
+	return 0;
+}
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
new file mode 100644
index 000000000..127c78aec
--- /dev/null
+++ b/kernel/trace/trace_uprobe.c
@@ -0,0 +1,1669 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * uprobes-based tracing events
+ *
+ * Copyright (C) IBM Corporation, 2010-2012
+ * Author:	Srikar Dronamraju <srikar@linux.vnet.ibm.com>
+ */
+#define pr_fmt(fmt)	"trace_uprobe: " fmt
+
+#include <linux/bpf-cgroup.h>
+#include <linux/security.h>
+#include <linux/ctype.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/uprobes.h>
+#include <linux/namei.h>
+#include <linux/string.h>
+#include <linux/rculist.h>
+#include <linux/filter.h>
+
+#include "trace_dynevent.h"
+#include "trace_probe.h"
+#include "trace_probe_tmpl.h"
+
+#define UPROBE_EVENT_SYSTEM	"uprobes"
+
+struct uprobe_trace_entry_head {
+	struct trace_entry	ent;
+	unsigned long		vaddr[];
+};
+
+#define SIZEOF_TRACE_ENTRY(is_return)			\
+	(sizeof(struct uprobe_trace_entry_head) +	\
+	 sizeof(unsigned long) * (is_return ? 2 : 1))
+
+#define DATAOF_TRACE_ENTRY(entry, is_return)		\
+	((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
+
+static int trace_uprobe_create(const char *raw_command);
+static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev);
+static int trace_uprobe_release(struct dyn_event *ev);
+static bool trace_uprobe_is_busy(struct dyn_event *ev);
+static bool trace_uprobe_match(const char *system, const char *event,
+			int argc, const char **argv, struct dyn_event *ev);
+
+static struct dyn_event_operations trace_uprobe_ops = {
+	.create = trace_uprobe_create,
+	.show = trace_uprobe_show,
+	.is_busy = trace_uprobe_is_busy,
+	.free = trace_uprobe_release,
+	.match = trace_uprobe_match,
+};
+
+/*
+ * uprobe event core functions
+ */
+struct trace_uprobe {
+	struct dyn_event		devent;
+	struct uprobe_consumer		consumer;
+	struct path			path;
+	struct inode			*inode;
+	char				*filename;
+	unsigned long			offset;
+	unsigned long			ref_ctr_offset;
+	unsigned long			nhit;
+	struct trace_probe		tp;
+};
+
+static bool is_trace_uprobe(struct dyn_event *ev)
+{
+	return ev->ops == &trace_uprobe_ops;
+}
+
+static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev)
+{
+	return container_of(ev, struct trace_uprobe, devent);
+}
+
+/**
+ * for_each_trace_uprobe - iterate over the trace_uprobe list
+ * @pos:	the struct trace_uprobe * for each entry
+ * @dpos:	the struct dyn_event * to use as a loop cursor
+ */
+#define for_each_trace_uprobe(pos, dpos)	\
+	for_each_dyn_event(dpos)		\
+		if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos)))
+
+static int register_uprobe_event(struct trace_uprobe *tu);
+static int unregister_uprobe_event(struct trace_uprobe *tu);
+
+struct uprobe_dispatch_data {
+	struct trace_uprobe	*tu;
+	unsigned long		bp_addr;
+};
+
+static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
+static int uretprobe_dispatcher(struct uprobe_consumer *con,
+				unsigned long func, struct pt_regs *regs);
+
+#ifdef CONFIG_STACK_GROWSUP
+static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
+{
+	return addr - (n * sizeof(long));
+}
+#else
+static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
+{
+	return addr + (n * sizeof(long));
+}
+#endif
+
+static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
+{
+	unsigned long ret;
+	unsigned long addr = user_stack_pointer(regs);
+
+	addr = adjust_stack_addr(addr, n);
+
+	if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
+		return 0;
+
+	return ret;
+}
+
+/*
+ * Uprobes-specific fetch functions
+ */
+static nokprobe_inline int
+probe_mem_read(void *dest, void *src, size_t size)
+{
+	void __user *vaddr = (void __force __user *)src;
+
+	return copy_from_user(dest, vaddr, size) ? -EFAULT : 0;
+}
+
+static nokprobe_inline int
+probe_mem_read_user(void *dest, void *src, size_t size)
+{
+	return probe_mem_read(dest, src, size);
+}
+
+/*
+ * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
+ * length and relative data location.
+ */
+static nokprobe_inline int
+fetch_store_string(unsigned long addr, void *dest, void *base)
+{
+	long ret;
+	u32 loc = *(u32 *)dest;
+	int maxlen  = get_loc_len(loc);
+	u8 *dst = get_loc_data(dest, base);
+	void __user *src = (void __force __user *) addr;
+
+	if (unlikely(!maxlen))
+		return -ENOMEM;
+
+	if (addr == FETCH_TOKEN_COMM)
+		ret = strlcpy(dst, current->comm, maxlen);
+	else
+		ret = strncpy_from_user(dst, src, maxlen);
+	if (ret >= 0) {
+		if (ret == maxlen)
+			dst[ret - 1] = '\0';
+		else
+			/*
+			 * Include the terminating null byte. In this case it
+			 * was copied by strncpy_from_user but not accounted
+			 * for in ret.
+			 */
+			ret++;
+		*(u32 *)dest = make_data_loc(ret, (void *)dst - base);
+	} else
+		*(u32 *)dest = make_data_loc(0, (void *)dst - base);
+
+	return ret;
+}
+
+static nokprobe_inline int
+fetch_store_string_user(unsigned long addr, void *dest, void *base)
+{
+	return fetch_store_string(addr, dest, base);
+}
+
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline int
+fetch_store_strlen(unsigned long addr)
+{
+	int len;
+	void __user *vaddr = (void __force __user *) addr;
+
+	if (addr == FETCH_TOKEN_COMM)
+		len = strlen(current->comm) + 1;
+	else
+		len = strnlen_user(vaddr, MAX_STRING_SIZE);
+
+	return (len > MAX_STRING_SIZE) ? 0 : len;
+}
+
+static nokprobe_inline int
+fetch_store_strlen_user(unsigned long addr)
+{
+	return fetch_store_strlen(addr);
+}
+
+static unsigned long translate_user_vaddr(unsigned long file_offset)
+{
+	unsigned long base_addr;
+	struct uprobe_dispatch_data *udd;
+
+	udd = (void *) current->utask->vaddr;
+
+	base_addr = udd->bp_addr - udd->tu->offset;
+	return base_addr + file_offset;
+}
+
+/* Note that we don't verify it, since the code does not come from user space */
+static int
+process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
+		   void *base)
+{
+	struct pt_regs *regs = rec;
+	unsigned long val;
+
+	/* 1st stage: get value from context */
+	switch (code->op) {
+	case FETCH_OP_REG:
+		val = regs_get_register(regs, code->param);
+		break;
+	case FETCH_OP_STACK:
+		val = get_user_stack_nth(regs, code->param);
+		break;
+	case FETCH_OP_STACKP:
+		val = user_stack_pointer(regs);
+		break;
+	case FETCH_OP_RETVAL:
+		val = regs_return_value(regs);
+		break;
+	case FETCH_OP_IMM:
+		val = code->immediate;
+		break;
+	case FETCH_OP_COMM:
+		val = FETCH_TOKEN_COMM;
+		break;
+	case FETCH_OP_DATA:
+		val = (unsigned long)code->data;
+		break;
+	case FETCH_OP_FOFFS:
+		val = translate_user_vaddr(code->immediate);
+		break;
+	default:
+		return -EILSEQ;
+	}
+	code++;
+
+	return process_fetch_insn_bottom(code, val, dest, base);
+}
+NOKPROBE_SYMBOL(process_fetch_insn)
+
+static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
+{
+	rwlock_init(&filter->rwlock);
+	filter->nr_systemwide = 0;
+	INIT_LIST_HEAD(&filter->perf_events);
+}
+
+static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
+{
+	return !filter->nr_systemwide && list_empty(&filter->perf_events);
+}
+
+static inline bool is_ret_probe(struct trace_uprobe *tu)
+{
+	return tu->consumer.ret_handler != NULL;
+}
+
+static bool trace_uprobe_is_busy(struct dyn_event *ev)
+{
+	struct trace_uprobe *tu = to_trace_uprobe(ev);
+
+	return trace_probe_is_enabled(&tu->tp);
+}
+
+static bool trace_uprobe_match_command_head(struct trace_uprobe *tu,
+					    int argc, const char **argv)
+{
+	char buf[MAX_ARGSTR_LEN + 1];
+	int len;
+
+	if (!argc)
+		return true;
+
+	len = strlen(tu->filename);
+	if (strncmp(tu->filename, argv[0], len) || argv[0][len] != ':')
+		return false;
+
+	if (tu->ref_ctr_offset == 0)
+		snprintf(buf, sizeof(buf), "0x%0*lx",
+				(int)(sizeof(void *) * 2), tu->offset);
+	else
+		snprintf(buf, sizeof(buf), "0x%0*lx(0x%lx)",
+				(int)(sizeof(void *) * 2), tu->offset,
+				tu->ref_ctr_offset);
+	if (strcmp(buf, &argv[0][len + 1]))
+		return false;
+
+	argc--; argv++;
+
+	return trace_probe_match_command_args(&tu->tp, argc, argv);
+}
+
+static bool trace_uprobe_match(const char *system, const char *event,
+			int argc, const char **argv, struct dyn_event *ev)
+{
+	struct trace_uprobe *tu = to_trace_uprobe(ev);
+
+	return (event[0] == '\0' ||
+		strcmp(trace_probe_name(&tu->tp), event) == 0) &&
+	   (!system || strcmp(trace_probe_group_name(&tu->tp), system) == 0) &&
+	   trace_uprobe_match_command_head(tu, argc, argv);
+}
+
+static nokprobe_inline struct trace_uprobe *
+trace_uprobe_primary_from_call(struct trace_event_call *call)
+{
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return NULL;
+
+	return container_of(tp, struct trace_uprobe, tp);
+}
+
+/*
+ * Allocate new trace_uprobe and initialize it (including uprobes).
+ */
+static struct trace_uprobe *
+alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
+{
+	struct trace_uprobe *tu;
+	int ret;
+
+	tu = kzalloc(struct_size(tu, tp.args, nargs), GFP_KERNEL);
+	if (!tu)
+		return ERR_PTR(-ENOMEM);
+
+	ret = trace_probe_init(&tu->tp, event, group, true);
+	if (ret < 0)
+		goto error;
+
+	dyn_event_init(&tu->devent, &trace_uprobe_ops);
+	tu->consumer.handler = uprobe_dispatcher;
+	if (is_ret)
+		tu->consumer.ret_handler = uretprobe_dispatcher;
+	init_trace_uprobe_filter(tu->tp.event->filter);
+	return tu;
+
+error:
+	kfree(tu);
+
+	return ERR_PTR(ret);
+}
+
+static void free_trace_uprobe(struct trace_uprobe *tu)
+{
+	if (!tu)
+		return;
+
+	path_put(&tu->path);
+	trace_probe_cleanup(&tu->tp);
+	kfree(tu->filename);
+	kfree(tu);
+}
+
+static struct trace_uprobe *find_probe_event(const char *event, const char *group)
+{
+	struct dyn_event *pos;
+	struct trace_uprobe *tu;
+
+	for_each_trace_uprobe(tu, pos)
+		if (strcmp(trace_probe_name(&tu->tp), event) == 0 &&
+		    strcmp(trace_probe_group_name(&tu->tp), group) == 0)
+			return tu;
+
+	return NULL;
+}
+
+/* Unregister a trace_uprobe and probe_event */
+static int unregister_trace_uprobe(struct trace_uprobe *tu)
+{
+	int ret;
+
+	if (trace_probe_has_sibling(&tu->tp))
+		goto unreg;
+
+	/* If there's a reference to the dynamic event */
+	if (trace_event_dyn_busy(trace_probe_event_call(&tu->tp)))
+		return -EBUSY;
+
+	ret = unregister_uprobe_event(tu);
+	if (ret)
+		return ret;
+
+unreg:
+	dyn_event_remove(&tu->devent);
+	trace_probe_unlink(&tu->tp);
+	free_trace_uprobe(tu);
+	return 0;
+}
+
+static bool trace_uprobe_has_same_uprobe(struct trace_uprobe *orig,
+					 struct trace_uprobe *comp)
+{
+	struct trace_probe_event *tpe = orig->tp.event;
+	struct inode *comp_inode = d_real_inode(comp->path.dentry);
+	int i;
+
+	list_for_each_entry(orig, &tpe->probes, tp.list) {
+		if (comp_inode != d_real_inode(orig->path.dentry) ||
+		    comp->offset != orig->offset)
+			continue;
+
+		/*
+		 * trace_probe_compare_arg_type() ensured that nr_args and
+		 * each argument name and type are same. Let's compare comm.
+		 */
+		for (i = 0; i < orig->tp.nr_args; i++) {
+			if (strcmp(orig->tp.args[i].comm,
+				   comp->tp.args[i].comm))
+				break;
+		}
+
+		if (i == orig->tp.nr_args)
+			return true;
+	}
+
+	return false;
+}
+
+static int append_trace_uprobe(struct trace_uprobe *tu, struct trace_uprobe *to)
+{
+	int ret;
+
+	ret = trace_probe_compare_arg_type(&tu->tp, &to->tp);
+	if (ret) {
+		/* Note that argument starts index = 2 */
+		trace_probe_log_set_index(ret + 1);
+		trace_probe_log_err(0, DIFF_ARG_TYPE);
+		return -EEXIST;
+	}
+	if (trace_uprobe_has_same_uprobe(to, tu)) {
+		trace_probe_log_set_index(0);
+		trace_probe_log_err(0, SAME_PROBE);
+		return -EEXIST;
+	}
+
+	/* Append to existing event */
+	ret = trace_probe_append(&tu->tp, &to->tp);
+	if (!ret)
+		dyn_event_add(&tu->devent, trace_probe_event_call(&tu->tp));
+
+	return ret;
+}
+
+/*
+ * Uprobe with multiple reference counter is not allowed. i.e.
+ * If inode and offset matches, reference counter offset *must*
+ * match as well. Though, there is one exception: If user is
+ * replacing old trace_uprobe with new one(same group/event),
+ * then we allow same uprobe with new reference counter as far
+ * as the new one does not conflict with any other existing
+ * ones.
+ */
+static int validate_ref_ctr_offset(struct trace_uprobe *new)
+{
+	struct dyn_event *pos;
+	struct trace_uprobe *tmp;
+	struct inode *new_inode = d_real_inode(new->path.dentry);
+
+	for_each_trace_uprobe(tmp, pos) {
+		if (new_inode == d_real_inode(tmp->path.dentry) &&
+		    new->offset == tmp->offset &&
+		    new->ref_ctr_offset != tmp->ref_ctr_offset) {
+			pr_warn("Reference counter offset mismatch.");
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+/* Register a trace_uprobe and probe_event */
+static int register_trace_uprobe(struct trace_uprobe *tu)
+{
+	struct trace_uprobe *old_tu;
+	int ret;
+
+	mutex_lock(&event_mutex);
+
+	ret = validate_ref_ctr_offset(tu);
+	if (ret)
+		goto end;
+
+	/* register as an event */
+	old_tu = find_probe_event(trace_probe_name(&tu->tp),
+				  trace_probe_group_name(&tu->tp));
+	if (old_tu) {
+		if (is_ret_probe(tu) != is_ret_probe(old_tu)) {
+			trace_probe_log_set_index(0);
+			trace_probe_log_err(0, DIFF_PROBE_TYPE);
+			ret = -EEXIST;
+		} else {
+			ret = append_trace_uprobe(tu, old_tu);
+		}
+		goto end;
+	}
+
+	ret = register_uprobe_event(tu);
+	if (ret) {
+		if (ret == -EEXIST) {
+			trace_probe_log_set_index(0);
+			trace_probe_log_err(0, EVENT_EXIST);
+		} else
+			pr_warn("Failed to register probe event(%d)\n", ret);
+		goto end;
+	}
+
+	dyn_event_add(&tu->devent, trace_probe_event_call(&tu->tp));
+
+end:
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+/*
+ * Argument syntax:
+ *  - Add uprobe: p|r[:[GRP/][EVENT]] PATH:OFFSET[%return][(REF)] [FETCHARGS]
+ */
+static int __trace_uprobe_create(int argc, const char **argv)
+{
+	struct trace_uprobe *tu;
+	const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
+	char *arg, *filename, *rctr, *rctr_end, *tmp;
+	char buf[MAX_EVENT_NAME_LEN];
+	char gbuf[MAX_EVENT_NAME_LEN];
+	enum probe_print_type ptype;
+	struct path path;
+	unsigned long offset, ref_ctr_offset;
+	bool is_return = false;
+	int i, ret;
+
+	ref_ctr_offset = 0;
+
+	switch (argv[0][0]) {
+	case 'r':
+		is_return = true;
+		break;
+	case 'p':
+		break;
+	default:
+		return -ECANCELED;
+	}
+
+	if (argc < 2)
+		return -ECANCELED;
+
+	if (argv[0][1] == ':')
+		event = &argv[0][2];
+
+	if (!strchr(argv[1], '/'))
+		return -ECANCELED;
+
+	filename = kstrdup(argv[1], GFP_KERNEL);
+	if (!filename)
+		return -ENOMEM;
+
+	/* Find the last occurrence, in case the path contains ':' too. */
+	arg = strrchr(filename, ':');
+	if (!arg || !isdigit(arg[1])) {
+		kfree(filename);
+		return -ECANCELED;
+	}
+
+	trace_probe_log_init("trace_uprobe", argc, argv);
+	trace_probe_log_set_index(1);	/* filename is the 2nd argument */
+
+	*arg++ = '\0';
+	ret = kern_path(filename, LOOKUP_FOLLOW, &path);
+	if (ret) {
+		trace_probe_log_err(0, FILE_NOT_FOUND);
+		kfree(filename);
+		trace_probe_log_clear();
+		return ret;
+	}
+	if (!d_is_reg(path.dentry)) {
+		trace_probe_log_err(0, NO_REGULAR_FILE);
+		ret = -EINVAL;
+		goto fail_address_parse;
+	}
+
+	/* Parse reference counter offset if specified. */
+	rctr = strchr(arg, '(');
+	if (rctr) {
+		rctr_end = strchr(rctr, ')');
+		if (!rctr_end) {
+			ret = -EINVAL;
+			rctr_end = rctr + strlen(rctr);
+			trace_probe_log_err(rctr_end - filename,
+					    REFCNT_OPEN_BRACE);
+			goto fail_address_parse;
+		} else if (rctr_end[1] != '\0') {
+			ret = -EINVAL;
+			trace_probe_log_err(rctr_end + 1 - filename,
+					    BAD_REFCNT_SUFFIX);
+			goto fail_address_parse;
+		}
+
+		*rctr++ = '\0';
+		*rctr_end = '\0';
+		ret = kstrtoul(rctr, 0, &ref_ctr_offset);
+		if (ret) {
+			trace_probe_log_err(rctr - filename, BAD_REFCNT);
+			goto fail_address_parse;
+		}
+	}
+
+	/* Check if there is %return suffix */
+	tmp = strchr(arg, '%');
+	if (tmp) {
+		if (!strcmp(tmp, "%return")) {
+			*tmp = '\0';
+			is_return = true;
+		} else {
+			trace_probe_log_err(tmp - filename, BAD_ADDR_SUFFIX);
+			ret = -EINVAL;
+			goto fail_address_parse;
+		}
+	}
+
+	/* Parse uprobe offset. */
+	ret = kstrtoul(arg, 0, &offset);
+	if (ret) {
+		trace_probe_log_err(arg - filename, BAD_UPROBE_OFFS);
+		goto fail_address_parse;
+	}
+
+	/* setup a probe */
+	trace_probe_log_set_index(0);
+	if (event) {
+		ret = traceprobe_parse_event_name(&event, &group, gbuf,
+						  event - argv[0]);
+		if (ret)
+			goto fail_address_parse;
+	}
+
+	if (!event) {
+		char *tail;
+		char *ptr;
+
+		tail = kstrdup(kbasename(filename), GFP_KERNEL);
+		if (!tail) {
+			ret = -ENOMEM;
+			goto fail_address_parse;
+		}
+
+		ptr = strpbrk(tail, ".-_");
+		if (ptr)
+			*ptr = '\0';
+
+		snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
+		event = buf;
+		kfree(tail);
+	}
+
+	argc -= 2;
+	argv += 2;
+
+	tu = alloc_trace_uprobe(group, event, argc, is_return);
+	if (IS_ERR(tu)) {
+		ret = PTR_ERR(tu);
+		/* This must return -ENOMEM otherwise there is a bug */
+		WARN_ON_ONCE(ret != -ENOMEM);
+		goto fail_address_parse;
+	}
+	tu->offset = offset;
+	tu->ref_ctr_offset = ref_ctr_offset;
+	tu->path = path;
+	tu->filename = filename;
+
+	/* parse arguments */
+	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
+		trace_probe_log_set_index(i + 2);
+		ret = traceprobe_parse_probe_arg(&tu->tp, i, argv[i],
+					is_return ? TPARG_FL_RETURN : 0);
+		if (ret)
+			goto error;
+	}
+
+	ptype = is_ret_probe(tu) ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
+	ret = traceprobe_set_print_fmt(&tu->tp, ptype);
+	if (ret < 0)
+		goto error;
+
+	ret = register_trace_uprobe(tu);
+	if (!ret)
+		goto out;
+
+error:
+	free_trace_uprobe(tu);
+out:
+	trace_probe_log_clear();
+	return ret;
+
+fail_address_parse:
+	trace_probe_log_clear();
+	path_put(&path);
+	kfree(filename);
+
+	return ret;
+}
+
+int trace_uprobe_create(const char *raw_command)
+{
+	return trace_probe_create(raw_command, __trace_uprobe_create);
+}
+
+static int create_or_delete_trace_uprobe(const char *raw_command)
+{
+	int ret;
+
+	if (raw_command[0] == '-')
+		return dyn_event_release(raw_command, &trace_uprobe_ops);
+
+	ret = trace_uprobe_create(raw_command);
+	return ret == -ECANCELED ? -EINVAL : ret;
+}
+
+static int trace_uprobe_release(struct dyn_event *ev)
+{
+	struct trace_uprobe *tu = to_trace_uprobe(ev);
+
+	return unregister_trace_uprobe(tu);
+}
+
+/* Probes listing interfaces */
+static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev)
+{
+	struct trace_uprobe *tu = to_trace_uprobe(ev);
+	char c = is_ret_probe(tu) ? 'r' : 'p';
+	int i;
+
+	seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, trace_probe_group_name(&tu->tp),
+			trace_probe_name(&tu->tp), tu->filename,
+			(int)(sizeof(void *) * 2), tu->offset);
+
+	if (tu->ref_ctr_offset)
+		seq_printf(m, "(0x%lx)", tu->ref_ctr_offset);
+
+	for (i = 0; i < tu->tp.nr_args; i++)
+		seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
+
+	seq_putc(m, '\n');
+	return 0;
+}
+
+static int probes_seq_show(struct seq_file *m, void *v)
+{
+	struct dyn_event *ev = v;
+
+	if (!is_trace_uprobe(ev))
+		return 0;
+
+	return trace_uprobe_show(m, ev);
+}
+
+static const struct seq_operations probes_seq_op = {
+	.start  = dyn_event_seq_start,
+	.next   = dyn_event_seq_next,
+	.stop   = dyn_event_seq_stop,
+	.show   = probes_seq_show
+};
+
+static int probes_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+		ret = dyn_events_release_all(&trace_uprobe_ops);
+		if (ret)
+			return ret;
+	}
+
+	return seq_open(file, &probes_seq_op);
+}
+
+static ssize_t probes_write(struct file *file, const char __user *buffer,
+			    size_t count, loff_t *ppos)
+{
+	return trace_parse_run_command(file, buffer, count, ppos,
+					create_or_delete_trace_uprobe);
+}
+
+static const struct file_operations uprobe_events_ops = {
+	.owner		= THIS_MODULE,
+	.open		= probes_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+	.write		= probes_write,
+};
+
+/* Probes profiling interfaces */
+static int probes_profile_seq_show(struct seq_file *m, void *v)
+{
+	struct dyn_event *ev = v;
+	struct trace_uprobe *tu;
+
+	if (!is_trace_uprobe(ev))
+		return 0;
+
+	tu = to_trace_uprobe(ev);
+	seq_printf(m, "  %s %-44s %15lu\n", tu->filename,
+			trace_probe_name(&tu->tp), tu->nhit);
+	return 0;
+}
+
+static const struct seq_operations profile_seq_op = {
+	.start  = dyn_event_seq_start,
+	.next   = dyn_event_seq_next,
+	.stop   = dyn_event_seq_stop,
+	.show	= probes_profile_seq_show
+};
+
+static int profile_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = security_locked_down(LOCKDOWN_TRACEFS);
+	if (ret)
+		return ret;
+
+	return seq_open(file, &profile_seq_op);
+}
+
+static const struct file_operations uprobe_profile_ops = {
+	.owner		= THIS_MODULE,
+	.open		= profile_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+struct uprobe_cpu_buffer {
+	struct mutex mutex;
+	void *buf;
+};
+static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
+static int uprobe_buffer_refcnt;
+
+static int uprobe_buffer_init(void)
+{
+	int cpu, err_cpu;
+
+	uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
+	if (uprobe_cpu_buffer == NULL)
+		return -ENOMEM;
+
+	for_each_possible_cpu(cpu) {
+		struct page *p = alloc_pages_node(cpu_to_node(cpu),
+						  GFP_KERNEL, 0);
+		if (p == NULL) {
+			err_cpu = cpu;
+			goto err;
+		}
+		per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
+		mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
+	}
+
+	return 0;
+
+err:
+	for_each_possible_cpu(cpu) {
+		if (cpu == err_cpu)
+			break;
+		free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
+	}
+
+	free_percpu(uprobe_cpu_buffer);
+	return -ENOMEM;
+}
+
+static int uprobe_buffer_enable(void)
+{
+	int ret = 0;
+
+	BUG_ON(!mutex_is_locked(&event_mutex));
+
+	if (uprobe_buffer_refcnt++ == 0) {
+		ret = uprobe_buffer_init();
+		if (ret < 0)
+			uprobe_buffer_refcnt--;
+	}
+
+	return ret;
+}
+
+static void uprobe_buffer_disable(void)
+{
+	int cpu;
+
+	BUG_ON(!mutex_is_locked(&event_mutex));
+
+	if (--uprobe_buffer_refcnt == 0) {
+		for_each_possible_cpu(cpu)
+			free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
+							     cpu)->buf);
+
+		free_percpu(uprobe_cpu_buffer);
+		uprobe_cpu_buffer = NULL;
+	}
+}
+
+static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
+{
+	struct uprobe_cpu_buffer *ucb;
+	int cpu;
+
+	cpu = raw_smp_processor_id();
+	ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
+
+	/*
+	 * Use per-cpu buffers for fastest access, but we might migrate
+	 * so the mutex makes sure we have sole access to it.
+	 */
+	mutex_lock(&ucb->mutex);
+
+	return ucb;
+}
+
+static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
+{
+	mutex_unlock(&ucb->mutex);
+}
+
+static void __uprobe_trace_func(struct trace_uprobe *tu,
+				unsigned long func, struct pt_regs *regs,
+				struct uprobe_cpu_buffer *ucb, int dsize,
+				struct trace_event_file *trace_file)
+{
+	struct uprobe_trace_entry_head *entry;
+	struct trace_event_buffer fbuffer;
+	void *data;
+	int size, esize;
+	struct trace_event_call *call = trace_probe_event_call(&tu->tp);
+
+	WARN_ON(call != trace_file->event_call);
+
+	if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
+		return;
+
+	if (trace_trigger_soft_disabled(trace_file))
+		return;
+
+	esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
+	size = esize + tu->tp.size + dsize;
+	entry = trace_event_buffer_reserve(&fbuffer, trace_file, size);
+	if (!entry)
+		return;
+
+	if (is_ret_probe(tu)) {
+		entry->vaddr[0] = func;
+		entry->vaddr[1] = instruction_pointer(regs);
+		data = DATAOF_TRACE_ENTRY(entry, true);
+	} else {
+		entry->vaddr[0] = instruction_pointer(regs);
+		data = DATAOF_TRACE_ENTRY(entry, false);
+	}
+
+	memcpy(data, ucb->buf, tu->tp.size + dsize);
+
+	trace_event_buffer_commit(&fbuffer);
+}
+
+/* uprobe handler */
+static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
+			     struct uprobe_cpu_buffer *ucb, int dsize)
+{
+	struct event_file_link *link;
+
+	if (is_ret_probe(tu))
+		return 0;
+
+	rcu_read_lock();
+	trace_probe_for_each_link_rcu(link, &tu->tp)
+		__uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
+	rcu_read_unlock();
+
+	return 0;
+}
+
+static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
+				 struct pt_regs *regs,
+				 struct uprobe_cpu_buffer *ucb, int dsize)
+{
+	struct event_file_link *link;
+
+	rcu_read_lock();
+	trace_probe_for_each_link_rcu(link, &tu->tp)
+		__uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
+	rcu_read_unlock();
+}
+
+/* Event entry printers */
+static enum print_line_t
+print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
+{
+	struct uprobe_trace_entry_head *entry;
+	struct trace_seq *s = &iter->seq;
+	struct trace_uprobe *tu;
+	u8 *data;
+
+	entry = (struct uprobe_trace_entry_head *)iter->ent;
+	tu = trace_uprobe_primary_from_call(
+		container_of(event, struct trace_event_call, event));
+	if (unlikely(!tu))
+		goto out;
+
+	if (is_ret_probe(tu)) {
+		trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
+				 trace_probe_name(&tu->tp),
+				 entry->vaddr[1], entry->vaddr[0]);
+		data = DATAOF_TRACE_ENTRY(entry, true);
+	} else {
+		trace_seq_printf(s, "%s: (0x%lx)",
+				 trace_probe_name(&tu->tp),
+				 entry->vaddr[0]);
+		data = DATAOF_TRACE_ENTRY(entry, false);
+	}
+
+	if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0)
+		goto out;
+
+	trace_seq_putc(s, '\n');
+
+ out:
+	return trace_handle_return(s);
+}
+
+typedef bool (*filter_func_t)(struct uprobe_consumer *self,
+				enum uprobe_filter_ctx ctx,
+				struct mm_struct *mm);
+
+static int trace_uprobe_enable(struct trace_uprobe *tu, filter_func_t filter)
+{
+	int ret;
+
+	tu->consumer.filter = filter;
+	tu->inode = d_real_inode(tu->path.dentry);
+
+	if (tu->ref_ctr_offset)
+		ret = uprobe_register_refctr(tu->inode, tu->offset,
+				tu->ref_ctr_offset, &tu->consumer);
+	else
+		ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
+
+	if (ret)
+		tu->inode = NULL;
+
+	return ret;
+}
+
+static void __probe_event_disable(struct trace_probe *tp)
+{
+	struct trace_uprobe *tu;
+
+	tu = container_of(tp, struct trace_uprobe, tp);
+	WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter));
+
+	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
+		if (!tu->inode)
+			continue;
+
+		uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
+		tu->inode = NULL;
+	}
+}
+
+static int probe_event_enable(struct trace_event_call *call,
+			struct trace_event_file *file, filter_func_t filter)
+{
+	struct trace_probe *tp;
+	struct trace_uprobe *tu;
+	bool enabled;
+	int ret;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENODEV;
+	enabled = trace_probe_is_enabled(tp);
+
+	/* This may also change "enabled" state */
+	if (file) {
+		if (trace_probe_test_flag(tp, TP_FLAG_PROFILE))
+			return -EINTR;
+
+		ret = trace_probe_add_file(tp, file);
+		if (ret < 0)
+			return ret;
+	} else {
+		if (trace_probe_test_flag(tp, TP_FLAG_TRACE))
+			return -EINTR;
+
+		trace_probe_set_flag(tp, TP_FLAG_PROFILE);
+	}
+
+	tu = container_of(tp, struct trace_uprobe, tp);
+	WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter));
+
+	if (enabled)
+		return 0;
+
+	ret = uprobe_buffer_enable();
+	if (ret)
+		goto err_flags;
+
+	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
+		ret = trace_uprobe_enable(tu, filter);
+		if (ret) {
+			__probe_event_disable(tp);
+			goto err_buffer;
+		}
+	}
+
+	return 0;
+
+ err_buffer:
+	uprobe_buffer_disable();
+
+ err_flags:
+	if (file)
+		trace_probe_remove_file(tp, file);
+	else
+		trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
+
+	return ret;
+}
+
+static void probe_event_disable(struct trace_event_call *call,
+				struct trace_event_file *file)
+{
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return;
+
+	if (!trace_probe_is_enabled(tp))
+		return;
+
+	if (file) {
+		if (trace_probe_remove_file(tp, file) < 0)
+			return;
+
+		if (trace_probe_is_enabled(tp))
+			return;
+	} else
+		trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
+
+	__probe_event_disable(tp);
+	uprobe_buffer_disable();
+}
+
+static int uprobe_event_define_fields(struct trace_event_call *event_call)
+{
+	int ret, size;
+	struct uprobe_trace_entry_head field;
+	struct trace_uprobe *tu;
+
+	tu = trace_uprobe_primary_from_call(event_call);
+	if (unlikely(!tu))
+		return -ENODEV;
+
+	if (is_ret_probe(tu)) {
+		DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
+		DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
+		size = SIZEOF_TRACE_ENTRY(true);
+	} else {
+		DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
+		size = SIZEOF_TRACE_ENTRY(false);
+	}
+
+	return traceprobe_define_arg_fields(event_call, size, &tu->tp);
+}
+
+#ifdef CONFIG_PERF_EVENTS
+static bool
+__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
+{
+	struct perf_event *event;
+
+	if (filter->nr_systemwide)
+		return true;
+
+	list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
+		if (event->hw.target->mm == mm)
+			return true;
+	}
+
+	return false;
+}
+
+static inline bool
+trace_uprobe_filter_event(struct trace_uprobe_filter *filter,
+			  struct perf_event *event)
+{
+	return __uprobe_perf_filter(filter, event->hw.target->mm);
+}
+
+static bool trace_uprobe_filter_remove(struct trace_uprobe_filter *filter,
+				       struct perf_event *event)
+{
+	bool done;
+
+	write_lock(&filter->rwlock);
+	if (event->hw.target) {
+		list_del(&event->hw.tp_list);
+		done = filter->nr_systemwide ||
+			(event->hw.target->flags & PF_EXITING) ||
+			trace_uprobe_filter_event(filter, event);
+	} else {
+		filter->nr_systemwide--;
+		done = filter->nr_systemwide;
+	}
+	write_unlock(&filter->rwlock);
+
+	return done;
+}
+
+/* This returns true if the filter always covers target mm */
+static bool trace_uprobe_filter_add(struct trace_uprobe_filter *filter,
+				    struct perf_event *event)
+{
+	bool done;
+
+	write_lock(&filter->rwlock);
+	if (event->hw.target) {
+		/*
+		 * event->parent != NULL means copy_process(), we can avoid
+		 * uprobe_apply(). current->mm must be probed and we can rely
+		 * on dup_mmap() which preserves the already installed bp's.
+		 *
+		 * attr.enable_on_exec means that exec/mmap will install the
+		 * breakpoints we need.
+		 */
+		done = filter->nr_systemwide ||
+			event->parent || event->attr.enable_on_exec ||
+			trace_uprobe_filter_event(filter, event);
+		list_add(&event->hw.tp_list, &filter->perf_events);
+	} else {
+		done = filter->nr_systemwide;
+		filter->nr_systemwide++;
+	}
+	write_unlock(&filter->rwlock);
+
+	return done;
+}
+
+static int uprobe_perf_close(struct trace_event_call *call,
+			     struct perf_event *event)
+{
+	struct trace_probe *tp;
+	struct trace_uprobe *tu;
+	int ret = 0;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENODEV;
+
+	tu = container_of(tp, struct trace_uprobe, tp);
+	if (trace_uprobe_filter_remove(tu->tp.event->filter, event))
+		return 0;
+
+	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
+		ret = uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static int uprobe_perf_open(struct trace_event_call *call,
+			    struct perf_event *event)
+{
+	struct trace_probe *tp;
+	struct trace_uprobe *tu;
+	int err = 0;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENODEV;
+
+	tu = container_of(tp, struct trace_uprobe, tp);
+	if (trace_uprobe_filter_add(tu->tp.event->filter, event))
+		return 0;
+
+	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
+		err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
+		if (err) {
+			uprobe_perf_close(call, event);
+			break;
+		}
+	}
+
+	return err;
+}
+
+static bool uprobe_perf_filter(struct uprobe_consumer *uc,
+				enum uprobe_filter_ctx ctx, struct mm_struct *mm)
+{
+	struct trace_uprobe_filter *filter;
+	struct trace_uprobe *tu;
+	int ret;
+
+	tu = container_of(uc, struct trace_uprobe, consumer);
+	filter = tu->tp.event->filter;
+
+	read_lock(&filter->rwlock);
+	ret = __uprobe_perf_filter(filter, mm);
+	read_unlock(&filter->rwlock);
+
+	return ret;
+}
+
+static void __uprobe_perf_func(struct trace_uprobe *tu,
+			       unsigned long func, struct pt_regs *regs,
+			       struct uprobe_cpu_buffer *ucb, int dsize)
+{
+	struct trace_event_call *call = trace_probe_event_call(&tu->tp);
+	struct uprobe_trace_entry_head *entry;
+	struct hlist_head *head;
+	void *data;
+	int size, esize;
+	int rctx;
+
+#ifdef CONFIG_BPF_EVENTS
+	if (bpf_prog_array_valid(call)) {
+		u32 ret;
+
+		ret = bpf_prog_run_array_sleepable(call->prog_array, regs, bpf_prog_run);
+		if (!ret)
+			return;
+	}
+#endif /* CONFIG_BPF_EVENTS */
+
+	esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
+
+	size = esize + tu->tp.size + dsize;
+	size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
+	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
+		return;
+
+	preempt_disable();
+	head = this_cpu_ptr(call->perf_events);
+	if (hlist_empty(head))
+		goto out;
+
+	entry = perf_trace_buf_alloc(size, NULL, &rctx);
+	if (!entry)
+		goto out;
+
+	if (is_ret_probe(tu)) {
+		entry->vaddr[0] = func;
+		entry->vaddr[1] = instruction_pointer(regs);
+		data = DATAOF_TRACE_ENTRY(entry, true);
+	} else {
+		entry->vaddr[0] = instruction_pointer(regs);
+		data = DATAOF_TRACE_ENTRY(entry, false);
+	}
+
+	memcpy(data, ucb->buf, tu->tp.size + dsize);
+
+	if (size - esize > tu->tp.size + dsize) {
+		int len = tu->tp.size + dsize;
+
+		memset(data + len, 0, size - esize - len);
+	}
+
+	perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
+			      head, NULL);
+ out:
+	preempt_enable();
+}
+
+/* uprobe profile handler */
+static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
+			    struct uprobe_cpu_buffer *ucb, int dsize)
+{
+	if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
+		return UPROBE_HANDLER_REMOVE;
+
+	if (!is_ret_probe(tu))
+		__uprobe_perf_func(tu, 0, regs, ucb, dsize);
+	return 0;
+}
+
+static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
+				struct pt_regs *regs,
+				struct uprobe_cpu_buffer *ucb, int dsize)
+{
+	__uprobe_perf_func(tu, func, regs, ucb, dsize);
+}
+
+int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type,
+			const char **filename, u64 *probe_offset,
+			u64 *probe_addr, bool perf_type_tracepoint)
+{
+	const char *pevent = trace_event_name(event->tp_event);
+	const char *group = event->tp_event->class->system;
+	struct trace_uprobe *tu;
+
+	if (perf_type_tracepoint)
+		tu = find_probe_event(pevent, group);
+	else
+		tu = trace_uprobe_primary_from_call(event->tp_event);
+	if (!tu)
+		return -EINVAL;
+
+	*fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE
+				    : BPF_FD_TYPE_UPROBE;
+	*filename = tu->filename;
+	*probe_offset = tu->offset;
+	*probe_addr = 0;
+	return 0;
+}
+#endif	/* CONFIG_PERF_EVENTS */
+
+static int
+trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
+		      void *data)
+{
+	struct trace_event_file *file = data;
+
+	switch (type) {
+	case TRACE_REG_REGISTER:
+		return probe_event_enable(event, file, NULL);
+
+	case TRACE_REG_UNREGISTER:
+		probe_event_disable(event, file);
+		return 0;
+
+#ifdef CONFIG_PERF_EVENTS
+	case TRACE_REG_PERF_REGISTER:
+		return probe_event_enable(event, NULL, uprobe_perf_filter);
+
+	case TRACE_REG_PERF_UNREGISTER:
+		probe_event_disable(event, NULL);
+		return 0;
+
+	case TRACE_REG_PERF_OPEN:
+		return uprobe_perf_open(event, data);
+
+	case TRACE_REG_PERF_CLOSE:
+		return uprobe_perf_close(event, data);
+
+#endif
+	default:
+		return 0;
+	}
+}
+
+static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
+{
+	struct trace_uprobe *tu;
+	struct uprobe_dispatch_data udd;
+	struct uprobe_cpu_buffer *ucb;
+	int dsize, esize;
+	int ret = 0;
+
+
+	tu = container_of(con, struct trace_uprobe, consumer);
+	tu->nhit++;
+
+	udd.tu = tu;
+	udd.bp_addr = instruction_pointer(regs);
+
+	current->utask->vaddr = (unsigned long) &udd;
+
+	if (WARN_ON_ONCE(!uprobe_cpu_buffer))
+		return 0;
+
+	dsize = __get_data_size(&tu->tp, regs);
+	esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
+
+	ucb = uprobe_buffer_get();
+	store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);
+
+	if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE))
+		ret |= uprobe_trace_func(tu, regs, ucb, dsize);
+
+#ifdef CONFIG_PERF_EVENTS
+	if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE))
+		ret |= uprobe_perf_func(tu, regs, ucb, dsize);
+#endif
+	uprobe_buffer_put(ucb);
+	return ret;
+}
+
+static int uretprobe_dispatcher(struct uprobe_consumer *con,
+				unsigned long func, struct pt_regs *regs)
+{
+	struct trace_uprobe *tu;
+	struct uprobe_dispatch_data udd;
+	struct uprobe_cpu_buffer *ucb;
+	int dsize, esize;
+
+	tu = container_of(con, struct trace_uprobe, consumer);
+
+	udd.tu = tu;
+	udd.bp_addr = func;
+
+	current->utask->vaddr = (unsigned long) &udd;
+
+	if (WARN_ON_ONCE(!uprobe_cpu_buffer))
+		return 0;
+
+	dsize = __get_data_size(&tu->tp, regs);
+	esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
+
+	ucb = uprobe_buffer_get();
+	store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);
+
+	if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE))
+		uretprobe_trace_func(tu, func, regs, ucb, dsize);
+
+#ifdef CONFIG_PERF_EVENTS
+	if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE))
+		uretprobe_perf_func(tu, func, regs, ucb, dsize);
+#endif
+	uprobe_buffer_put(ucb);
+	return 0;
+}
+
+static struct trace_event_functions uprobe_funcs = {
+	.trace		= print_uprobe_event
+};
+
+static struct trace_event_fields uprobe_fields_array[] = {
+	{ .type = TRACE_FUNCTION_TYPE,
+	  .define_fields = uprobe_event_define_fields },
+	{}
+};
+
+static inline void init_trace_event_call(struct trace_uprobe *tu)
+{
+	struct trace_event_call *call = trace_probe_event_call(&tu->tp);
+	call->event.funcs = &uprobe_funcs;
+	call->class->fields_array = uprobe_fields_array;
+
+	call->flags = TRACE_EVENT_FL_UPROBE | TRACE_EVENT_FL_CAP_ANY;
+	call->class->reg = trace_uprobe_register;
+}
+
+static int register_uprobe_event(struct trace_uprobe *tu)
+{
+	init_trace_event_call(tu);
+
+	return trace_probe_register_event_call(&tu->tp);
+}
+
+static int unregister_uprobe_event(struct trace_uprobe *tu)
+{
+	return trace_probe_unregister_event_call(&tu->tp);
+}
+
+#ifdef CONFIG_PERF_EVENTS
+struct trace_event_call *
+create_local_trace_uprobe(char *name, unsigned long offs,
+			  unsigned long ref_ctr_offset, bool is_return)
+{
+	enum probe_print_type ptype;
+	struct trace_uprobe *tu;
+	struct path path;
+	int ret;
+
+	ret = kern_path(name, LOOKUP_FOLLOW, &path);
+	if (ret)
+		return ERR_PTR(ret);
+
+	if (!d_is_reg(path.dentry)) {
+		path_put(&path);
+		return ERR_PTR(-EINVAL);
+	}
+
+	/*
+	 * local trace_kprobes are not added to dyn_event, so they are never
+	 * searched in find_trace_kprobe(). Therefore, there is no concern of
+	 * duplicated name "DUMMY_EVENT" here.
+	 */
+	tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
+				is_return);
+
+	if (IS_ERR(tu)) {
+		pr_info("Failed to allocate trace_uprobe.(%d)\n",
+			(int)PTR_ERR(tu));
+		path_put(&path);
+		return ERR_CAST(tu);
+	}
+
+	tu->offset = offs;
+	tu->path = path;
+	tu->ref_ctr_offset = ref_ctr_offset;
+	tu->filename = kstrdup(name, GFP_KERNEL);
+	if (!tu->filename) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	init_trace_event_call(tu);
+
+	ptype = is_ret_probe(tu) ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
+	if (traceprobe_set_print_fmt(&tu->tp, ptype) < 0) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	return trace_probe_event_call(&tu->tp);
+error:
+	free_trace_uprobe(tu);
+	return ERR_PTR(ret);
+}
+
+void destroy_local_trace_uprobe(struct trace_event_call *event_call)
+{
+	struct trace_uprobe *tu;
+
+	tu = trace_uprobe_primary_from_call(event_call);
+
+	free_trace_uprobe(tu);
+}
+#endif /* CONFIG_PERF_EVENTS */
+
+/* Make a trace interface for controlling probe points */
+static __init int init_uprobe_trace(void)
+{
+	int ret;
+
+	ret = dyn_event_register(&trace_uprobe_ops);
+	if (ret)
+		return ret;
+
+	ret = tracing_init_dentry();
+	if (ret)
+		return 0;
+
+	trace_create_file("uprobe_events", TRACE_MODE_WRITE, NULL,
+				    NULL, &uprobe_events_ops);
+	/* Profile interface */
+	trace_create_file("uprobe_profile", TRACE_MODE_READ, NULL,
+				    NULL, &uprobe_profile_ops);
+	return 0;
+}
+
+fs_initcall(init_uprobe_trace);
diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c
new file mode 100644
index 000000000..a4dcf0f24
--- /dev/null
+++ b/kernel/trace/tracing_map.c
@@ -0,0 +1,1139 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * tracing_map - lock-free map for tracing
+ *
+ * Copyright (C) 2015 Tom Zanussi <tom.zanussi@linux.intel.com>
+ *
+ * tracing_map implementation inspired by lock-free map algorithms
+ * originated by Dr. Cliff Click:
+ *
+ * http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable
+ * http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf
+ */
+
+#include <linux/vmalloc.h>
+#include <linux/jhash.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include <linux/kmemleak.h>
+
+#include "tracing_map.h"
+#include "trace.h"
+
+/*
+ * NOTE: For a detailed description of the data structures used by
+ * these functions (such as tracing_map_elt) please see the overview
+ * of tracing_map data structures at the beginning of tracing_map.h.
+ */
+
+/**
+ * tracing_map_update_sum - Add a value to a tracing_map_elt's sum field
+ * @elt: The tracing_map_elt
+ * @i: The index of the given sum associated with the tracing_map_elt
+ * @n: The value to add to the sum
+ *
+ * Add n to sum i associated with the specified tracing_map_elt
+ * instance.  The index i is the index returned by the call to
+ * tracing_map_add_sum_field() when the tracing map was set up.
+ */
+void tracing_map_update_sum(struct tracing_map_elt *elt, unsigned int i, u64 n)
+{
+	atomic64_add(n, &elt->fields[i].sum);
+}
+
+/**
+ * tracing_map_read_sum - Return the value of a tracing_map_elt's sum field
+ * @elt: The tracing_map_elt
+ * @i: The index of the given sum associated with the tracing_map_elt
+ *
+ * Retrieve the value of the sum i associated with the specified
+ * tracing_map_elt instance.  The index i is the index returned by the
+ * call to tracing_map_add_sum_field() when the tracing map was set
+ * up.
+ *
+ * Return: The sum associated with field i for elt.
+ */
+u64 tracing_map_read_sum(struct tracing_map_elt *elt, unsigned int i)
+{
+	return (u64)atomic64_read(&elt->fields[i].sum);
+}
+
+/**
+ * tracing_map_set_var - Assign a tracing_map_elt's variable field
+ * @elt: The tracing_map_elt
+ * @i: The index of the given variable associated with the tracing_map_elt
+ * @n: The value to assign
+ *
+ * Assign n to variable i associated with the specified tracing_map_elt
+ * instance.  The index i is the index returned by the call to
+ * tracing_map_add_var() when the tracing map was set up.
+ */
+void tracing_map_set_var(struct tracing_map_elt *elt, unsigned int i, u64 n)
+{
+	atomic64_set(&elt->vars[i], n);
+	elt->var_set[i] = true;
+}
+
+/**
+ * tracing_map_var_set - Return whether or not a variable has been set
+ * @elt: The tracing_map_elt
+ * @i: The index of the given variable associated with the tracing_map_elt
+ *
+ * Return true if the variable has been set, false otherwise.  The
+ * index i is the index returned by the call to tracing_map_add_var()
+ * when the tracing map was set up.
+ */
+bool tracing_map_var_set(struct tracing_map_elt *elt, unsigned int i)
+{
+	return elt->var_set[i];
+}
+
+/**
+ * tracing_map_read_var - Return the value of a tracing_map_elt's variable field
+ * @elt: The tracing_map_elt
+ * @i: The index of the given variable associated with the tracing_map_elt
+ *
+ * Retrieve the value of the variable i associated with the specified
+ * tracing_map_elt instance.  The index i is the index returned by the
+ * call to tracing_map_add_var() when the tracing map was set
+ * up.
+ *
+ * Return: The variable value associated with field i for elt.
+ */
+u64 tracing_map_read_var(struct tracing_map_elt *elt, unsigned int i)
+{
+	return (u64)atomic64_read(&elt->vars[i]);
+}
+
+/**
+ * tracing_map_read_var_once - Return and reset a tracing_map_elt's variable field
+ * @elt: The tracing_map_elt
+ * @i: The index of the given variable associated with the tracing_map_elt
+ *
+ * Retrieve the value of the variable i associated with the specified
+ * tracing_map_elt instance, and reset the variable to the 'not set'
+ * state.  The index i is the index returned by the call to
+ * tracing_map_add_var() when the tracing map was set up.  The reset
+ * essentially makes the variable a read-once variable if it's only
+ * accessed using this function.
+ *
+ * Return: The variable value associated with field i for elt.
+ */
+u64 tracing_map_read_var_once(struct tracing_map_elt *elt, unsigned int i)
+{
+	elt->var_set[i] = false;
+	return (u64)atomic64_read(&elt->vars[i]);
+}
+
+int tracing_map_cmp_string(void *val_a, void *val_b)
+{
+	char *a = val_a;
+	char *b = val_b;
+
+	return strcmp(a, b);
+}
+
+int tracing_map_cmp_none(void *val_a, void *val_b)
+{
+	return 0;
+}
+
+static int tracing_map_cmp_atomic64(void *val_a, void *val_b)
+{
+	u64 a = atomic64_read((atomic64_t *)val_a);
+	u64 b = atomic64_read((atomic64_t *)val_b);
+
+	return (a > b) ? 1 : ((a < b) ? -1 : 0);
+}
+
+#define DEFINE_TRACING_MAP_CMP_FN(type)					\
+static int tracing_map_cmp_##type(void *val_a, void *val_b)		\
+{									\
+	type a = (type)(*(u64 *)val_a);					\
+	type b = (type)(*(u64 *)val_b);					\
+									\
+	return (a > b) ? 1 : ((a < b) ? -1 : 0);			\
+}
+
+DEFINE_TRACING_MAP_CMP_FN(s64);
+DEFINE_TRACING_MAP_CMP_FN(u64);
+DEFINE_TRACING_MAP_CMP_FN(s32);
+DEFINE_TRACING_MAP_CMP_FN(u32);
+DEFINE_TRACING_MAP_CMP_FN(s16);
+DEFINE_TRACING_MAP_CMP_FN(u16);
+DEFINE_TRACING_MAP_CMP_FN(s8);
+DEFINE_TRACING_MAP_CMP_FN(u8);
+
+tracing_map_cmp_fn_t tracing_map_cmp_num(int field_size,
+					 int field_is_signed)
+{
+	tracing_map_cmp_fn_t fn = tracing_map_cmp_none;
+
+	switch (field_size) {
+	case 8:
+		if (field_is_signed)
+			fn = tracing_map_cmp_s64;
+		else
+			fn = tracing_map_cmp_u64;
+		break;
+	case 4:
+		if (field_is_signed)
+			fn = tracing_map_cmp_s32;
+		else
+			fn = tracing_map_cmp_u32;
+		break;
+	case 2:
+		if (field_is_signed)
+			fn = tracing_map_cmp_s16;
+		else
+			fn = tracing_map_cmp_u16;
+		break;
+	case 1:
+		if (field_is_signed)
+			fn = tracing_map_cmp_s8;
+		else
+			fn = tracing_map_cmp_u8;
+		break;
+	}
+
+	return fn;
+}
+
+static int tracing_map_add_field(struct tracing_map *map,
+				 tracing_map_cmp_fn_t cmp_fn)
+{
+	int ret = -EINVAL;
+
+	if (map->n_fields < TRACING_MAP_FIELDS_MAX) {
+		ret = map->n_fields;
+		map->fields[map->n_fields++].cmp_fn = cmp_fn;
+	}
+
+	return ret;
+}
+
+/**
+ * tracing_map_add_sum_field - Add a field describing a tracing_map sum
+ * @map: The tracing_map
+ *
+ * Add a sum field to the key and return the index identifying it in
+ * the map and associated tracing_map_elts.  This is the index used
+ * for instance to update a sum for a particular tracing_map_elt using
+ * tracing_map_update_sum() or reading it via tracing_map_read_sum().
+ *
+ * Return: The index identifying the field in the map and associated
+ * tracing_map_elts, or -EINVAL on error.
+ */
+int tracing_map_add_sum_field(struct tracing_map *map)
+{
+	return tracing_map_add_field(map, tracing_map_cmp_atomic64);
+}
+
+/**
+ * tracing_map_add_var - Add a field describing a tracing_map var
+ * @map: The tracing_map
+ *
+ * Add a var to the map and return the index identifying it in the map
+ * and associated tracing_map_elts.  This is the index used for
+ * instance to update a var for a particular tracing_map_elt using
+ * tracing_map_update_var() or reading it via tracing_map_read_var().
+ *
+ * Return: The index identifying the var in the map and associated
+ * tracing_map_elts, or -EINVAL on error.
+ */
+int tracing_map_add_var(struct tracing_map *map)
+{
+	int ret = -EINVAL;
+
+	if (map->n_vars < TRACING_MAP_VARS_MAX)
+		ret = map->n_vars++;
+
+	return ret;
+}
+
+/**
+ * tracing_map_add_key_field - Add a field describing a tracing_map key
+ * @map: The tracing_map
+ * @offset: The offset within the key
+ * @cmp_fn: The comparison function that will be used to sort on the key
+ *
+ * Let the map know there is a key and that if it's used as a sort key
+ * to use cmp_fn.
+ *
+ * A key can be a subset of a compound key; for that purpose, the
+ * offset param is used to describe where within the compound key
+ * the key referenced by this key field resides.
+ *
+ * Return: The index identifying the field in the map and associated
+ * tracing_map_elts, or -EINVAL on error.
+ */
+int tracing_map_add_key_field(struct tracing_map *map,
+			      unsigned int offset,
+			      tracing_map_cmp_fn_t cmp_fn)
+
+{
+	int idx = tracing_map_add_field(map, cmp_fn);
+
+	if (idx < 0)
+		return idx;
+
+	map->fields[idx].offset = offset;
+
+	map->key_idx[map->n_keys++] = idx;
+
+	return idx;
+}
+
+static void tracing_map_array_clear(struct tracing_map_array *a)
+{
+	unsigned int i;
+
+	if (!a->pages)
+		return;
+
+	for (i = 0; i < a->n_pages; i++)
+		memset(a->pages[i], 0, PAGE_SIZE);
+}
+
+static void tracing_map_array_free(struct tracing_map_array *a)
+{
+	unsigned int i;
+
+	if (!a)
+		return;
+
+	if (!a->pages)
+		goto free;
+
+	for (i = 0; i < a->n_pages; i++) {
+		if (!a->pages[i])
+			break;
+		kmemleak_free(a->pages[i]);
+		free_page((unsigned long)a->pages[i]);
+	}
+
+	kfree(a->pages);
+
+ free:
+	kfree(a);
+}
+
+static struct tracing_map_array *tracing_map_array_alloc(unsigned int n_elts,
+						  unsigned int entry_size)
+{
+	struct tracing_map_array *a;
+	unsigned int i;
+
+	a = kzalloc(sizeof(*a), GFP_KERNEL);
+	if (!a)
+		return NULL;
+
+	a->entry_size_shift = fls(roundup_pow_of_two(entry_size) - 1);
+	a->entries_per_page = PAGE_SIZE / (1 << a->entry_size_shift);
+	a->n_pages = n_elts / a->entries_per_page;
+	if (!a->n_pages)
+		a->n_pages = 1;
+	a->entry_shift = fls(a->entries_per_page) - 1;
+	a->entry_mask = (1 << a->entry_shift) - 1;
+
+	a->pages = kcalloc(a->n_pages, sizeof(void *), GFP_KERNEL);
+	if (!a->pages)
+		goto free;
+
+	for (i = 0; i < a->n_pages; i++) {
+		a->pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
+		if (!a->pages[i])
+			goto free;
+		kmemleak_alloc(a->pages[i], PAGE_SIZE, 1, GFP_KERNEL);
+	}
+ out:
+	return a;
+ free:
+	tracing_map_array_free(a);
+	a = NULL;
+
+	goto out;
+}
+
+static void tracing_map_elt_clear(struct tracing_map_elt *elt)
+{
+	unsigned i;
+
+	for (i = 0; i < elt->map->n_fields; i++)
+		if (elt->fields[i].cmp_fn == tracing_map_cmp_atomic64)
+			atomic64_set(&elt->fields[i].sum, 0);
+
+	for (i = 0; i < elt->map->n_vars; i++) {
+		atomic64_set(&elt->vars[i], 0);
+		elt->var_set[i] = false;
+	}
+
+	if (elt->map->ops && elt->map->ops->elt_clear)
+		elt->map->ops->elt_clear(elt);
+}
+
+static void tracing_map_elt_init_fields(struct tracing_map_elt *elt)
+{
+	unsigned int i;
+
+	tracing_map_elt_clear(elt);
+
+	for (i = 0; i < elt->map->n_fields; i++) {
+		elt->fields[i].cmp_fn = elt->map->fields[i].cmp_fn;
+
+		if (elt->fields[i].cmp_fn != tracing_map_cmp_atomic64)
+			elt->fields[i].offset = elt->map->fields[i].offset;
+	}
+}
+
+static void tracing_map_elt_free(struct tracing_map_elt *elt)
+{
+	if (!elt)
+		return;
+
+	if (elt->map->ops && elt->map->ops->elt_free)
+		elt->map->ops->elt_free(elt);
+	kfree(elt->fields);
+	kfree(elt->vars);
+	kfree(elt->var_set);
+	kfree(elt->key);
+	kfree(elt);
+}
+
+static struct tracing_map_elt *tracing_map_elt_alloc(struct tracing_map *map)
+{
+	struct tracing_map_elt *elt;
+	int err = 0;
+
+	elt = kzalloc(sizeof(*elt), GFP_KERNEL);
+	if (!elt)
+		return ERR_PTR(-ENOMEM);
+
+	elt->map = map;
+
+	elt->key = kzalloc(map->key_size, GFP_KERNEL);
+	if (!elt->key) {
+		err = -ENOMEM;
+		goto free;
+	}
+
+	elt->fields = kcalloc(map->n_fields, sizeof(*elt->fields), GFP_KERNEL);
+	if (!elt->fields) {
+		err = -ENOMEM;
+		goto free;
+	}
+
+	elt->vars = kcalloc(map->n_vars, sizeof(*elt->vars), GFP_KERNEL);
+	if (!elt->vars) {
+		err = -ENOMEM;
+		goto free;
+	}
+
+	elt->var_set = kcalloc(map->n_vars, sizeof(*elt->var_set), GFP_KERNEL);
+	if (!elt->var_set) {
+		err = -ENOMEM;
+		goto free;
+	}
+
+	tracing_map_elt_init_fields(elt);
+
+	if (map->ops && map->ops->elt_alloc) {
+		err = map->ops->elt_alloc(elt);
+		if (err)
+			goto free;
+	}
+	return elt;
+ free:
+	tracing_map_elt_free(elt);
+
+	return ERR_PTR(err);
+}
+
+static struct tracing_map_elt *get_free_elt(struct tracing_map *map)
+{
+	struct tracing_map_elt *elt = NULL;
+	int idx;
+
+	idx = atomic_inc_return(&map->next_elt);
+	if (idx < map->max_elts) {
+		elt = *(TRACING_MAP_ELT(map->elts, idx));
+		if (map->ops && map->ops->elt_init)
+			map->ops->elt_init(elt);
+	}
+
+	return elt;
+}
+
+static void tracing_map_free_elts(struct tracing_map *map)
+{
+	unsigned int i;
+
+	if (!map->elts)
+		return;
+
+	for (i = 0; i < map->max_elts; i++) {
+		tracing_map_elt_free(*(TRACING_MAP_ELT(map->elts, i)));
+		*(TRACING_MAP_ELT(map->elts, i)) = NULL;
+	}
+
+	tracing_map_array_free(map->elts);
+	map->elts = NULL;
+}
+
+static int tracing_map_alloc_elts(struct tracing_map *map)
+{
+	unsigned int i;
+
+	map->elts = tracing_map_array_alloc(map->max_elts,
+					    sizeof(struct tracing_map_elt *));
+	if (!map->elts)
+		return -ENOMEM;
+
+	for (i = 0; i < map->max_elts; i++) {
+		*(TRACING_MAP_ELT(map->elts, i)) = tracing_map_elt_alloc(map);
+		if (IS_ERR(*(TRACING_MAP_ELT(map->elts, i)))) {
+			*(TRACING_MAP_ELT(map->elts, i)) = NULL;
+			tracing_map_free_elts(map);
+
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+static inline bool keys_match(void *key, void *test_key, unsigned key_size)
+{
+	bool match = true;
+
+	if (memcmp(key, test_key, key_size))
+		match = false;
+
+	return match;
+}
+
+static inline struct tracing_map_elt *
+__tracing_map_insert(struct tracing_map *map, void *key, bool lookup_only)
+{
+	u32 idx, key_hash, test_key;
+	int dup_try = 0;
+	struct tracing_map_entry *entry;
+	struct tracing_map_elt *val;
+
+	key_hash = jhash(key, map->key_size, 0);
+	if (key_hash == 0)
+		key_hash = 1;
+	idx = key_hash >> (32 - (map->map_bits + 1));
+
+	while (1) {
+		idx &= (map->map_size - 1);
+		entry = TRACING_MAP_ENTRY(map->map, idx);
+		test_key = entry->key;
+
+		if (test_key && test_key == key_hash) {
+			val = READ_ONCE(entry->val);
+			if (val &&
+			    keys_match(key, val->key, map->key_size)) {
+				if (!lookup_only)
+					atomic64_inc(&map->hits);
+				return val;
+			} else if (unlikely(!val)) {
+				/*
+				 * The key is present. But, val (pointer to elt
+				 * struct) is still NULL. which means some other
+				 * thread is in the process of inserting an
+				 * element.
+				 *
+				 * On top of that, it's key_hash is same as the
+				 * one being inserted right now. So, it's
+				 * possible that the element has the same
+				 * key as well.
+				 */
+
+				dup_try++;
+				if (dup_try > map->map_size) {
+					atomic64_inc(&map->drops);
+					break;
+				}
+				continue;
+			}
+		}
+
+		if (!test_key) {
+			if (lookup_only)
+				break;
+
+			if (!cmpxchg(&entry->key, 0, key_hash)) {
+				struct tracing_map_elt *elt;
+
+				elt = get_free_elt(map);
+				if (!elt) {
+					atomic64_inc(&map->drops);
+					entry->key = 0;
+					break;
+				}
+
+				memcpy(elt->key, key, map->key_size);
+				/*
+				 * Ensure the initialization is visible and
+				 * publish the elt.
+				 */
+				smp_wmb();
+				WRITE_ONCE(entry->val, elt);
+				atomic64_inc(&map->hits);
+
+				return entry->val;
+			} else {
+				/*
+				 * cmpxchg() failed. Loop around once
+				 * more to check what key was inserted.
+				 */
+				dup_try++;
+				continue;
+			}
+		}
+
+		idx++;
+	}
+
+	return NULL;
+}
+
+/**
+ * tracing_map_insert - Insert key and/or retrieve val from a tracing_map
+ * @map: The tracing_map to insert into
+ * @key: The key to insert
+ *
+ * Inserts a key into a tracing_map and creates and returns a new
+ * tracing_map_elt for it, or if the key has already been inserted by
+ * a previous call, returns the tracing_map_elt already associated
+ * with it.  When the map was created, the number of elements to be
+ * allocated for the map was specified (internally maintained as
+ * 'max_elts' in struct tracing_map), and that number of
+ * tracing_map_elts was created by tracing_map_init().  This is the
+ * pre-allocated pool of tracing_map_elts that tracing_map_insert()
+ * will allocate from when adding new keys.  Once that pool is
+ * exhausted, tracing_map_insert() is useless and will return NULL to
+ * signal that state.  There are two user-visible tracing_map
+ * variables, 'hits' and 'drops', which are updated by this function.
+ * Every time an element is either successfully inserted or retrieved,
+ * the 'hits' value is incremented.  Every time an element insertion
+ * fails, the 'drops' value is incremented.
+ *
+ * This is a lock-free tracing map insertion function implementing a
+ * modified form of Cliff Click's basic insertion algorithm.  It
+ * requires the table size be a power of two.  To prevent any
+ * possibility of an infinite loop we always make the internal table
+ * size double the size of the requested table size (max_elts * 2).
+ * Likewise, we never reuse a slot or resize or delete elements - when
+ * we've reached max_elts entries, we simply return NULL once we've
+ * run out of entries.  Readers can at any point in time traverse the
+ * tracing map and safely access the key/val pairs.
+ *
+ * Return: the tracing_map_elt pointer val associated with the key.
+ * If this was a newly inserted key, the val will be a newly allocated
+ * and associated tracing_map_elt pointer val.  If the key wasn't
+ * found and the pool of tracing_map_elts has been exhausted, NULL is
+ * returned and no further insertions will succeed.
+ */
+struct tracing_map_elt *tracing_map_insert(struct tracing_map *map, void *key)
+{
+	return __tracing_map_insert(map, key, false);
+}
+
+/**
+ * tracing_map_lookup - Retrieve val from a tracing_map
+ * @map: The tracing_map to perform the lookup on
+ * @key: The key to look up
+ *
+ * Looks up key in tracing_map and if found returns the matching
+ * tracing_map_elt.  This is a lock-free lookup; see
+ * tracing_map_insert() for details on tracing_map and how it works.
+ * Every time an element is retrieved, the 'hits' value is
+ * incremented.  There is one user-visible tracing_map variable,
+ * 'hits', which is updated by this function.  Every time an element
+ * is successfully retrieved, the 'hits' value is incremented.  The
+ * 'drops' value is never updated by this function.
+ *
+ * Return: the tracing_map_elt pointer val associated with the key.
+ * If the key wasn't found, NULL is returned.
+ */
+struct tracing_map_elt *tracing_map_lookup(struct tracing_map *map, void *key)
+{
+	return __tracing_map_insert(map, key, true);
+}
+
+/**
+ * tracing_map_destroy - Destroy a tracing_map
+ * @map: The tracing_map to destroy
+ *
+ * Frees a tracing_map along with its associated array of
+ * tracing_map_elts.
+ *
+ * Callers should make sure there are no readers or writers actively
+ * reading or inserting into the map before calling this.
+ */
+void tracing_map_destroy(struct tracing_map *map)
+{
+	if (!map)
+		return;
+
+	tracing_map_free_elts(map);
+
+	tracing_map_array_free(map->map);
+	kfree(map);
+}
+
+/**
+ * tracing_map_clear - Clear a tracing_map
+ * @map: The tracing_map to clear
+ *
+ * Resets the tracing map to a cleared or initial state.  The
+ * tracing_map_elts are all cleared, and the array of struct
+ * tracing_map_entry is reset to an initialized state.
+ *
+ * Callers should make sure there are no writers actively inserting
+ * into the map before calling this.
+ */
+void tracing_map_clear(struct tracing_map *map)
+{
+	unsigned int i;
+
+	atomic_set(&map->next_elt, -1);
+	atomic64_set(&map->hits, 0);
+	atomic64_set(&map->drops, 0);
+
+	tracing_map_array_clear(map->map);
+
+	for (i = 0; i < map->max_elts; i++)
+		tracing_map_elt_clear(*(TRACING_MAP_ELT(map->elts, i)));
+}
+
+static void set_sort_key(struct tracing_map *map,
+			 struct tracing_map_sort_key *sort_key)
+{
+	map->sort_key = *sort_key;
+}
+
+/**
+ * tracing_map_create - Create a lock-free map and element pool
+ * @map_bits: The size of the map (2 ** map_bits)
+ * @key_size: The size of the key for the map in bytes
+ * @ops: Optional client-defined tracing_map_ops instance
+ * @private_data: Client data associated with the map
+ *
+ * Creates and sets up a map to contain 2 ** map_bits number of
+ * elements (internally maintained as 'max_elts' in struct
+ * tracing_map).  Before using, map fields should be added to the map
+ * with tracing_map_add_sum_field() and tracing_map_add_key_field().
+ * tracing_map_init() should then be called to allocate the array of
+ * tracing_map_elts, in order to avoid allocating anything in the map
+ * insertion path.  The user-specified map size reflects the maximum
+ * number of elements that can be contained in the table requested by
+ * the user - internally we double that in order to keep the table
+ * sparse and keep collisions manageable.
+ *
+ * A tracing_map is a special-purpose map designed to aggregate or
+ * 'sum' one or more values associated with a specific object of type
+ * tracing_map_elt, which is attached by the map to a given key.
+ *
+ * tracing_map_create() sets up the map itself, and provides
+ * operations for inserting tracing_map_elts, but doesn't allocate the
+ * tracing_map_elts themselves, or provide a means for describing the
+ * keys or sums associated with the tracing_map_elts.  All
+ * tracing_map_elts for a given map have the same set of sums and
+ * keys, which are defined by the client using the functions
+ * tracing_map_add_key_field() and tracing_map_add_sum_field().  Once
+ * the fields are defined, the pool of elements allocated for the map
+ * can be created, which occurs when the client code calls
+ * tracing_map_init().
+ *
+ * When tracing_map_init() returns, tracing_map_elt elements can be
+ * inserted into the map using tracing_map_insert().  When called,
+ * tracing_map_insert() grabs a free tracing_map_elt from the pool, or
+ * finds an existing match in the map and in either case returns it.
+ * The client can then use tracing_map_update_sum() and
+ * tracing_map_read_sum() to update or read a given sum field for the
+ * tracing_map_elt.
+ *
+ * The client can at any point retrieve and traverse the current set
+ * of inserted tracing_map_elts in a tracing_map, via
+ * tracing_map_sort_entries().  Sorting can be done on any field,
+ * including keys.
+ *
+ * See tracing_map.h for a description of tracing_map_ops.
+ *
+ * Return: the tracing_map pointer if successful, ERR_PTR if not.
+ */
+struct tracing_map *tracing_map_create(unsigned int map_bits,
+				       unsigned int key_size,
+				       const struct tracing_map_ops *ops,
+				       void *private_data)
+{
+	struct tracing_map *map;
+	unsigned int i;
+
+	if (map_bits < TRACING_MAP_BITS_MIN ||
+	    map_bits > TRACING_MAP_BITS_MAX)
+		return ERR_PTR(-EINVAL);
+
+	map = kzalloc(sizeof(*map), GFP_KERNEL);
+	if (!map)
+		return ERR_PTR(-ENOMEM);
+
+	map->map_bits = map_bits;
+	map->max_elts = (1 << map_bits);
+	atomic_set(&map->next_elt, -1);
+
+	map->map_size = (1 << (map_bits + 1));
+	map->ops = ops;
+
+	map->private_data = private_data;
+
+	map->map = tracing_map_array_alloc(map->map_size,
+					   sizeof(struct tracing_map_entry));
+	if (!map->map)
+		goto free;
+
+	map->key_size = key_size;
+	for (i = 0; i < TRACING_MAP_KEYS_MAX; i++)
+		map->key_idx[i] = -1;
+ out:
+	return map;
+ free:
+	tracing_map_destroy(map);
+	map = ERR_PTR(-ENOMEM);
+
+	goto out;
+}
+
+/**
+ * tracing_map_init - Allocate and clear a map's tracing_map_elts
+ * @map: The tracing_map to initialize
+ *
+ * Allocates a clears a pool of tracing_map_elts equal to the
+ * user-specified size of 2 ** map_bits (internally maintained as
+ * 'max_elts' in struct tracing_map).  Before using, the map fields
+ * should be added to the map with tracing_map_add_sum_field() and
+ * tracing_map_add_key_field().  tracing_map_init() should then be
+ * called to allocate the array of tracing_map_elts, in order to avoid
+ * allocating anything in the map insertion path.  The user-specified
+ * map size reflects the max number of elements requested by the user
+ * - internally we double that in order to keep the table sparse and
+ * keep collisions manageable.
+ *
+ * See tracing_map.h for a description of tracing_map_ops.
+ *
+ * Return: the tracing_map pointer if successful, ERR_PTR if not.
+ */
+int tracing_map_init(struct tracing_map *map)
+{
+	int err;
+
+	if (map->n_fields < 2)
+		return -EINVAL; /* need at least 1 key and 1 val */
+
+	err = tracing_map_alloc_elts(map);
+	if (err)
+		return err;
+
+	tracing_map_clear(map);
+
+	return err;
+}
+
+static int cmp_entries_dup(const void *A, const void *B)
+{
+	const struct tracing_map_sort_entry *a, *b;
+	int ret = 0;
+
+	a = *(const struct tracing_map_sort_entry **)A;
+	b = *(const struct tracing_map_sort_entry **)B;
+
+	if (memcmp(a->key, b->key, a->elt->map->key_size))
+		ret = 1;
+
+	return ret;
+}
+
+static int cmp_entries_sum(const void *A, const void *B)
+{
+	const struct tracing_map_elt *elt_a, *elt_b;
+	const struct tracing_map_sort_entry *a, *b;
+	struct tracing_map_sort_key *sort_key;
+	struct tracing_map_field *field;
+	tracing_map_cmp_fn_t cmp_fn;
+	void *val_a, *val_b;
+	int ret = 0;
+
+	a = *(const struct tracing_map_sort_entry **)A;
+	b = *(const struct tracing_map_sort_entry **)B;
+
+	elt_a = a->elt;
+	elt_b = b->elt;
+
+	sort_key = &elt_a->map->sort_key;
+
+	field = &elt_a->fields[sort_key->field_idx];
+	cmp_fn = field->cmp_fn;
+
+	val_a = &elt_a->fields[sort_key->field_idx].sum;
+	val_b = &elt_b->fields[sort_key->field_idx].sum;
+
+	ret = cmp_fn(val_a, val_b);
+	if (sort_key->descending)
+		ret = -ret;
+
+	return ret;
+}
+
+static int cmp_entries_key(const void *A, const void *B)
+{
+	const struct tracing_map_elt *elt_a, *elt_b;
+	const struct tracing_map_sort_entry *a, *b;
+	struct tracing_map_sort_key *sort_key;
+	struct tracing_map_field *field;
+	tracing_map_cmp_fn_t cmp_fn;
+	void *val_a, *val_b;
+	int ret = 0;
+
+	a = *(const struct tracing_map_sort_entry **)A;
+	b = *(const struct tracing_map_sort_entry **)B;
+
+	elt_a = a->elt;
+	elt_b = b->elt;
+
+	sort_key = &elt_a->map->sort_key;
+
+	field = &elt_a->fields[sort_key->field_idx];
+
+	cmp_fn = field->cmp_fn;
+
+	val_a = elt_a->key + field->offset;
+	val_b = elt_b->key + field->offset;
+
+	ret = cmp_fn(val_a, val_b);
+	if (sort_key->descending)
+		ret = -ret;
+
+	return ret;
+}
+
+static void destroy_sort_entry(struct tracing_map_sort_entry *entry)
+{
+	if (!entry)
+		return;
+
+	if (entry->elt_copied)
+		tracing_map_elt_free(entry->elt);
+
+	kfree(entry);
+}
+
+/**
+ * tracing_map_destroy_sort_entries - Destroy an array of sort entries
+ * @entries: The entries to destroy
+ * @n_entries: The number of entries in the array
+ *
+ * Destroy the elements returned by a tracing_map_sort_entries() call.
+ */
+void tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries,
+				      unsigned int n_entries)
+{
+	unsigned int i;
+
+	for (i = 0; i < n_entries; i++)
+		destroy_sort_entry(entries[i]);
+
+	vfree(entries);
+}
+
+static struct tracing_map_sort_entry *
+create_sort_entry(void *key, struct tracing_map_elt *elt)
+{
+	struct tracing_map_sort_entry *sort_entry;
+
+	sort_entry = kzalloc(sizeof(*sort_entry), GFP_KERNEL);
+	if (!sort_entry)
+		return NULL;
+
+	sort_entry->key = key;
+	sort_entry->elt = elt;
+
+	return sort_entry;
+}
+
+static void detect_dups(struct tracing_map_sort_entry **sort_entries,
+		      int n_entries, unsigned int key_size)
+{
+	unsigned int total_dups = 0;
+	int i;
+	void *key;
+
+	if (n_entries < 2)
+		return;
+
+	sort(sort_entries, n_entries, sizeof(struct tracing_map_sort_entry *),
+	     (int (*)(const void *, const void *))cmp_entries_dup, NULL);
+
+	key = sort_entries[0]->key;
+	for (i = 1; i < n_entries; i++) {
+		if (!memcmp(sort_entries[i]->key, key, key_size)) {
+			total_dups++;
+			continue;
+		}
+		key = sort_entries[i]->key;
+	}
+
+	WARN_ONCE(total_dups > 0,
+		  "Duplicates detected: %d\n", total_dups);
+}
+
+static bool is_key(struct tracing_map *map, unsigned int field_idx)
+{
+	unsigned int i;
+
+	for (i = 0; i < map->n_keys; i++)
+		if (map->key_idx[i] == field_idx)
+			return true;
+	return false;
+}
+
+static void sort_secondary(struct tracing_map *map,
+			   const struct tracing_map_sort_entry **entries,
+			   unsigned int n_entries,
+			   struct tracing_map_sort_key *primary_key,
+			   struct tracing_map_sort_key *secondary_key)
+{
+	int (*primary_fn)(const void *, const void *);
+	int (*secondary_fn)(const void *, const void *);
+	unsigned i, start = 0, n_sub = 1;
+
+	if (is_key(map, primary_key->field_idx))
+		primary_fn = cmp_entries_key;
+	else
+		primary_fn = cmp_entries_sum;
+
+	if (is_key(map, secondary_key->field_idx))
+		secondary_fn = cmp_entries_key;
+	else
+		secondary_fn = cmp_entries_sum;
+
+	for (i = 0; i < n_entries - 1; i++) {
+		const struct tracing_map_sort_entry **a = &entries[i];
+		const struct tracing_map_sort_entry **b = &entries[i + 1];
+
+		if (primary_fn(a, b) == 0) {
+			n_sub++;
+			if (i < n_entries - 2)
+				continue;
+		}
+
+		if (n_sub < 2) {
+			start = i + 1;
+			n_sub = 1;
+			continue;
+		}
+
+		set_sort_key(map, secondary_key);
+		sort(&entries[start], n_sub,
+		     sizeof(struct tracing_map_sort_entry *),
+		     (int (*)(const void *, const void *))secondary_fn, NULL);
+		set_sort_key(map, primary_key);
+
+		start = i + 1;
+		n_sub = 1;
+	}
+}
+
+/**
+ * tracing_map_sort_entries - Sort the current set of tracing_map_elts in a map
+ * @map: The tracing_map
+ * @sort_keys: The sort key to use for sorting
+ * @n_sort_keys: hitcount, always have at least one
+ * @sort_entries: outval: pointer to allocated and sorted array of entries
+ *
+ * tracing_map_sort_entries() sorts the current set of entries in the
+ * map and returns the list of tracing_map_sort_entries containing
+ * them to the client in the sort_entries param.  The client can
+ * access the struct tracing_map_elt element of interest directly as
+ * the 'elt' field of a returned struct tracing_map_sort_entry object.
+ *
+ * The sort_key has only two fields: idx and descending.  'idx' refers
+ * to the index of the field added via tracing_map_add_sum_field() or
+ * tracing_map_add_key_field() when the tracing_map was initialized.
+ * 'descending' is a flag that if set reverses the sort order, which
+ * by default is ascending.
+ *
+ * The client should not hold on to the returned array but should use
+ * it and call tracing_map_destroy_sort_entries() when done.
+ *
+ * Return: the number of sort_entries in the struct tracing_map_sort_entry
+ * array, negative on error
+ */
+int tracing_map_sort_entries(struct tracing_map *map,
+			     struct tracing_map_sort_key *sort_keys,
+			     unsigned int n_sort_keys,
+			     struct tracing_map_sort_entry ***sort_entries)
+{
+	int (*cmp_entries_fn)(const void *, const void *);
+	struct tracing_map_sort_entry *sort_entry, **entries;
+	int i, n_entries, ret;
+
+	entries = vmalloc(array_size(sizeof(sort_entry), map->max_elts));
+	if (!entries)
+		return -ENOMEM;
+
+	for (i = 0, n_entries = 0; i < map->map_size; i++) {
+		struct tracing_map_entry *entry;
+
+		entry = TRACING_MAP_ENTRY(map->map, i);
+
+		if (!entry->key || !entry->val)
+			continue;
+
+		entries[n_entries] = create_sort_entry(entry->val->key,
+						       entry->val);
+		if (!entries[n_entries++]) {
+			ret = -ENOMEM;
+			goto free;
+		}
+	}
+
+	if (n_entries == 0) {
+		ret = 0;
+		goto free;
+	}
+
+	if (n_entries == 1) {
+		*sort_entries = entries;
+		return 1;
+	}
+
+	detect_dups(entries, n_entries, map->key_size);
+
+	if (is_key(map, sort_keys[0].field_idx))
+		cmp_entries_fn = cmp_entries_key;
+	else
+		cmp_entries_fn = cmp_entries_sum;
+
+	set_sort_key(map, &sort_keys[0]);
+
+	sort(entries, n_entries, sizeof(struct tracing_map_sort_entry *),
+	     (int (*)(const void *, const void *))cmp_entries_fn, NULL);
+
+	if (n_sort_keys > 1)
+		sort_secondary(map,
+			       (const struct tracing_map_sort_entry **)entries,
+			       n_entries,
+			       &sort_keys[0],
+			       &sort_keys[1]);
+
+	*sort_entries = entries;
+
+	return n_entries;
+ free:
+	tracing_map_destroy_sort_entries(entries, n_entries);
+
+	return ret;
+}
diff --git a/kernel/trace/tracing_map.h b/kernel/trace/tracing_map.h
new file mode 100644
index 000000000..2c765ee2a
--- /dev/null
+++ b/kernel/trace/tracing_map.h
@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef __TRACING_MAP_H
+#define __TRACING_MAP_H
+
+#define TRACING_MAP_BITS_DEFAULT	11
+#define TRACING_MAP_BITS_MAX		17
+#define TRACING_MAP_BITS_MIN		7
+
+#define TRACING_MAP_KEYS_MAX		3
+#define TRACING_MAP_VALS_MAX		3
+#define TRACING_MAP_FIELDS_MAX		(TRACING_MAP_KEYS_MAX + \
+					 TRACING_MAP_VALS_MAX)
+#define TRACING_MAP_VARS_MAX		16
+#define TRACING_MAP_SORT_KEYS_MAX	2
+
+typedef int (*tracing_map_cmp_fn_t) (void *val_a, void *val_b);
+
+/*
+ * This is an overview of the tracing_map data structures and how they
+ * relate to the tracing_map API.  The details of the algorithms
+ * aren't discussed here - this is just a general overview of the data
+ * structures and how they interact with the API.
+ *
+ * The central data structure of the tracing_map is an initially
+ * zeroed array of struct tracing_map_entry (stored in the map field
+ * of struct tracing_map).  tracing_map_entry is a very simple data
+ * structure containing only two fields: a 32-bit unsigned 'key'
+ * variable and a pointer named 'val'.  This array of struct
+ * tracing_map_entry is essentially a hash table which will be
+ * modified by a single function, tracing_map_insert(), but which can
+ * be traversed and read by a user at any time (though the user does
+ * this indirectly via an array of tracing_map_sort_entry - see the
+ * explanation of that data structure in the discussion of the
+ * sorting-related data structures below).
+ *
+ * The central function of the tracing_map API is
+ * tracing_map_insert().  tracing_map_insert() hashes the
+ * arbitrarily-sized key passed into it into a 32-bit unsigned key.
+ * It then uses this key, truncated to the array size, as an index
+ * into the array of tracing_map_entries.  If the value of the 'key'
+ * field of the tracing_map_entry found at that location is 0, then
+ * that entry is considered to be free and can be claimed, by
+ * replacing the 0 in the 'key' field of the tracing_map_entry with
+ * the new 32-bit hashed key.  Once claimed, that tracing_map_entry's
+ * 'val' field is then used to store a unique element which will be
+ * forever associated with that 32-bit hashed key in the
+ * tracing_map_entry.
+ *
+ * That unique element now in the tracing_map_entry's 'val' field is
+ * an instance of tracing_map_elt, where 'elt' in the latter part of
+ * that variable name is short for 'element'.  The purpose of a
+ * tracing_map_elt is to hold values specific to the particular
+ * 32-bit hashed key it's associated with.  Things such as the unique
+ * set of aggregated sums associated with the 32-bit hashed key, along
+ * with a copy of the full key associated with the entry, and which
+ * was used to produce the 32-bit hashed key.
+ *
+ * When tracing_map_create() is called to create the tracing map, the
+ * user specifies (indirectly via the map_bits param, the details are
+ * unimportant for this discussion) the maximum number of elements
+ * that the map can hold (stored in the max_elts field of struct
+ * tracing_map).  This is the maximum possible number of
+ * tracing_map_entries in the tracing_map_entry array which can be
+ * 'claimed' as described in the above discussion, and therefore is
+ * also the maximum number of tracing_map_elts that can be associated
+ * with the tracing_map_entry array in the tracing_map.  Because of
+ * the way the insertion algorithm works, the size of the allocated
+ * tracing_map_entry array is always twice the maximum number of
+ * elements (2 * max_elts).  This value is stored in the map_size
+ * field of struct tracing_map.
+ *
+ * Because tracing_map_insert() needs to work from any context,
+ * including from within the memory allocation functions themselves,
+ * both the tracing_map_entry array and a pool of max_elts
+ * tracing_map_elts are pre-allocated before any call is made to
+ * tracing_map_insert().
+ *
+ * The tracing_map_entry array is allocated as a single block by
+ * tracing_map_create().
+ *
+ * Because the tracing_map_elts are much larger objects and can't
+ * generally be allocated together as a single large array without
+ * failure, they're allocated individually, by tracing_map_init().
+ *
+ * The pool of tracing_map_elts are allocated by tracing_map_init()
+ * rather than by tracing_map_create() because at the time
+ * tracing_map_create() is called, there isn't enough information to
+ * create the tracing_map_elts.  Specifically,the user first needs to
+ * tell the tracing_map implementation how many fields the
+ * tracing_map_elts contain, and which types of fields they are (key
+ * or sum).  The user does this via the tracing_map_add_sum_field()
+ * and tracing_map_add_key_field() functions, following which the user
+ * calls tracing_map_init() to finish up the tracing map setup.  The
+ * array holding the pointers which make up the pre-allocated pool of
+ * tracing_map_elts is allocated as a single block and is stored in
+ * the elts field of struct tracing_map.
+ *
+ * There is also a set of structures used for sorting that might
+ * benefit from some minimal explanation.
+ *
+ * struct tracing_map_sort_key is used to drive the sort at any given
+ * time.  By 'any given time' we mean that a different
+ * tracing_map_sort_key will be used at different times depending on
+ * whether the sort currently being performed is a primary or a
+ * secondary sort.
+ *
+ * The sort key is very simple, consisting of the field index of the
+ * tracing_map_elt field to sort on (which the user saved when adding
+ * the field), and whether the sort should be done in an ascending or
+ * descending order.
+ *
+ * For the convenience of the sorting code, a tracing_map_sort_entry
+ * is created for each tracing_map_elt, again individually allocated
+ * to avoid failures that might be expected if allocated as a single
+ * large array of struct tracing_map_sort_entry.
+ * tracing_map_sort_entry instances are the objects expected by the
+ * various internal sorting functions, and are also what the user
+ * ultimately receives after calling tracing_map_sort_entries().
+ * Because it doesn't make sense for users to access an unordered and
+ * sparsely populated tracing_map directly, the
+ * tracing_map_sort_entries() function is provided so that users can
+ * retrieve a sorted list of all existing elements.  In addition to
+ * the associated tracing_map_elt 'elt' field contained within the
+ * tracing_map_sort_entry, which is the object of interest to the
+ * user, tracing_map_sort_entry objects contain a number of additional
+ * fields which are used for caching and internal purposes and can
+ * safely be ignored.
+*/
+
+struct tracing_map_field {
+	tracing_map_cmp_fn_t		cmp_fn;
+	union {
+		atomic64_t			sum;
+		unsigned int			offset;
+	};
+};
+
+struct tracing_map_elt {
+	struct tracing_map		*map;
+	struct tracing_map_field	*fields;
+	atomic64_t			*vars;
+	bool				*var_set;
+	void				*key;
+	void				*private_data;
+};
+
+struct tracing_map_entry {
+	u32				key;
+	struct tracing_map_elt		*val;
+};
+
+struct tracing_map_sort_key {
+	unsigned int			field_idx;
+	bool				descending;
+};
+
+struct tracing_map_sort_entry {
+	void				*key;
+	struct tracing_map_elt		*elt;
+	bool				elt_copied;
+	bool				dup;
+};
+
+struct tracing_map_array {
+	unsigned int entries_per_page;
+	unsigned int entry_size_shift;
+	unsigned int entry_shift;
+	unsigned int entry_mask;
+	unsigned int n_pages;
+	void **pages;
+};
+
+#define TRACING_MAP_ARRAY_ELT(array, idx)				\
+	(array->pages[idx >> array->entry_shift] +			\
+	 ((idx & array->entry_mask) << array->entry_size_shift))
+
+#define TRACING_MAP_ENTRY(array, idx)					\
+	((struct tracing_map_entry *)TRACING_MAP_ARRAY_ELT(array, idx))
+
+#define TRACING_MAP_ELT(array, idx)					\
+	((struct tracing_map_elt **)TRACING_MAP_ARRAY_ELT(array, idx))
+
+struct tracing_map {
+	unsigned int			key_size;
+	unsigned int			map_bits;
+	unsigned int			map_size;
+	unsigned int			max_elts;
+	atomic_t			next_elt;
+	struct tracing_map_array	*elts;
+	struct tracing_map_array	*map;
+	const struct tracing_map_ops	*ops;
+	void				*private_data;
+	struct tracing_map_field	fields[TRACING_MAP_FIELDS_MAX];
+	unsigned int			n_fields;
+	int				key_idx[TRACING_MAP_KEYS_MAX];
+	unsigned int			n_keys;
+	struct tracing_map_sort_key	sort_key;
+	unsigned int			n_vars;
+	atomic64_t			hits;
+	atomic64_t			drops;
+};
+
+/**
+ * struct tracing_map_ops - callbacks for tracing_map
+ *
+ * The methods in this structure define callback functions for various
+ * operations on a tracing_map or objects related to a tracing_map.
+ *
+ * For a detailed description of tracing_map_elt objects please see
+ * the overview of tracing_map data structures at the beginning of
+ * this file.
+ *
+ * All the methods below are optional.
+ *
+ * @elt_alloc: When a tracing_map_elt is allocated, this function, if
+ *	defined, will be called and gives clients the opportunity to
+ *	allocate additional data and attach it to the element
+ *	(tracing_map_elt->private_data is meant for that purpose).
+ *	Element allocation occurs before tracing begins, when the
+ *	tracing_map_init() call is made by client code.
+ *
+ * @elt_free: When a tracing_map_elt is freed, this function is called
+ *	and allows client-allocated per-element data to be freed.
+ *
+ * @elt_clear: This callback allows per-element client-defined data to
+ *	be cleared, if applicable.
+ *
+ * @elt_init: This callback allows per-element client-defined data to
+ *	be initialized when used i.e. when the element is actually
+ *	claimed by tracing_map_insert() in the context of the map
+ *	insertion.
+ */
+struct tracing_map_ops {
+	int			(*elt_alloc)(struct tracing_map_elt *elt);
+	void			(*elt_free)(struct tracing_map_elt *elt);
+	void			(*elt_clear)(struct tracing_map_elt *elt);
+	void			(*elt_init)(struct tracing_map_elt *elt);
+};
+
+extern struct tracing_map *
+tracing_map_create(unsigned int map_bits,
+		   unsigned int key_size,
+		   const struct tracing_map_ops *ops,
+		   void *private_data);
+extern int tracing_map_init(struct tracing_map *map);
+
+extern int tracing_map_add_sum_field(struct tracing_map *map);
+extern int tracing_map_add_var(struct tracing_map *map);
+extern int tracing_map_add_key_field(struct tracing_map *map,
+				     unsigned int offset,
+				     tracing_map_cmp_fn_t cmp_fn);
+
+extern void tracing_map_destroy(struct tracing_map *map);
+extern void tracing_map_clear(struct tracing_map *map);
+
+extern struct tracing_map_elt *
+tracing_map_insert(struct tracing_map *map, void *key);
+extern struct tracing_map_elt *
+tracing_map_lookup(struct tracing_map *map, void *key);
+
+extern tracing_map_cmp_fn_t tracing_map_cmp_num(int field_size,
+						int field_is_signed);
+extern int tracing_map_cmp_string(void *val_a, void *val_b);
+extern int tracing_map_cmp_none(void *val_a, void *val_b);
+
+extern void tracing_map_update_sum(struct tracing_map_elt *elt,
+				   unsigned int i, u64 n);
+extern void tracing_map_set_var(struct tracing_map_elt *elt,
+				unsigned int i, u64 n);
+extern bool tracing_map_var_set(struct tracing_map_elt *elt, unsigned int i);
+extern u64 tracing_map_read_sum(struct tracing_map_elt *elt, unsigned int i);
+extern u64 tracing_map_read_var(struct tracing_map_elt *elt, unsigned int i);
+extern u64 tracing_map_read_var_once(struct tracing_map_elt *elt, unsigned int i);
+
+extern void tracing_map_set_field_descr(struct tracing_map *map,
+					unsigned int i,
+					unsigned int key_offset,
+					tracing_map_cmp_fn_t cmp_fn);
+extern int
+tracing_map_sort_entries(struct tracing_map *map,
+			 struct tracing_map_sort_key *sort_keys,
+			 unsigned int n_sort_keys,
+			 struct tracing_map_sort_entry ***sort_entries);
+
+extern void
+tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries,
+				 unsigned int n_entries);
+#endif /* __TRACING_MAP_H */
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
new file mode 100644
index 000000000..f23144af5
--- /dev/null
+++ b/kernel/tracepoint.c
@@ -0,0 +1,787 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2008-2014 Mathieu Desnoyers
+ */
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/jhash.h>
+#include <linux/list.h>
+#include <linux/rcupdate.h>
+#include <linux/tracepoint.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/task.h>
+#include <linux/static_key.h>
+
+enum tp_func_state {
+	TP_FUNC_0,
+	TP_FUNC_1,
+	TP_FUNC_2,
+	TP_FUNC_N,
+};
+
+extern tracepoint_ptr_t __start___tracepoints_ptrs[];
+extern tracepoint_ptr_t __stop___tracepoints_ptrs[];
+
+DEFINE_SRCU(tracepoint_srcu);
+EXPORT_SYMBOL_GPL(tracepoint_srcu);
+
+enum tp_transition_sync {
+	TP_TRANSITION_SYNC_1_0_1,
+	TP_TRANSITION_SYNC_N_2_1,
+
+	_NR_TP_TRANSITION_SYNC,
+};
+
+struct tp_transition_snapshot {
+	unsigned long rcu;
+	unsigned long srcu;
+	bool ongoing;
+};
+
+/* Protected by tracepoints_mutex */
+static struct tp_transition_snapshot tp_transition_snapshot[_NR_TP_TRANSITION_SYNC];
+
+static void tp_rcu_get_state(enum tp_transition_sync sync)
+{
+	struct tp_transition_snapshot *snapshot = &tp_transition_snapshot[sync];
+
+	/* Keep the latest get_state snapshot. */
+	snapshot->rcu = get_state_synchronize_rcu();
+	snapshot->srcu = start_poll_synchronize_srcu(&tracepoint_srcu);
+	snapshot->ongoing = true;
+}
+
+static void tp_rcu_cond_sync(enum tp_transition_sync sync)
+{
+	struct tp_transition_snapshot *snapshot = &tp_transition_snapshot[sync];
+
+	if (!snapshot->ongoing)
+		return;
+	cond_synchronize_rcu(snapshot->rcu);
+	if (!poll_state_synchronize_srcu(&tracepoint_srcu, snapshot->srcu))
+		synchronize_srcu(&tracepoint_srcu);
+	snapshot->ongoing = false;
+}
+
+/* Set to 1 to enable tracepoint debug output */
+static const int tracepoint_debug;
+
+#ifdef CONFIG_MODULES
+/*
+ * Tracepoint module list mutex protects the local module list.
+ */
+static DEFINE_MUTEX(tracepoint_module_list_mutex);
+
+/* Local list of struct tp_module */
+static LIST_HEAD(tracepoint_module_list);
+#endif /* CONFIG_MODULES */
+
+/*
+ * tracepoints_mutex protects the builtin and module tracepoints.
+ * tracepoints_mutex nests inside tracepoint_module_list_mutex.
+ */
+static DEFINE_MUTEX(tracepoints_mutex);
+
+static struct rcu_head *early_probes;
+static bool ok_to_free_tracepoints;
+
+/*
+ * Note about RCU :
+ * It is used to delay the free of multiple probes array until a quiescent
+ * state is reached.
+ */
+struct tp_probes {
+	struct rcu_head rcu;
+	struct tracepoint_func probes[];
+};
+
+/* Called in removal of a func but failed to allocate a new tp_funcs */
+static void tp_stub_func(void)
+{
+	return;
+}
+
+static inline void *allocate_probes(int count)
+{
+	struct tp_probes *p  = kmalloc(struct_size(p, probes, count),
+				       GFP_KERNEL);
+	return p == NULL ? NULL : p->probes;
+}
+
+static void srcu_free_old_probes(struct rcu_head *head)
+{
+	kfree(container_of(head, struct tp_probes, rcu));
+}
+
+static void rcu_free_old_probes(struct rcu_head *head)
+{
+	call_srcu(&tracepoint_srcu, head, srcu_free_old_probes);
+}
+
+static __init int release_early_probes(void)
+{
+	struct rcu_head *tmp;
+
+	ok_to_free_tracepoints = true;
+
+	while (early_probes) {
+		tmp = early_probes;
+		early_probes = tmp->next;
+		call_rcu(tmp, rcu_free_old_probes);
+	}
+
+	return 0;
+}
+
+/* SRCU is initialized at core_initcall */
+postcore_initcall(release_early_probes);
+
+static inline void release_probes(struct tracepoint_func *old)
+{
+	if (old) {
+		struct tp_probes *tp_probes = container_of(old,
+			struct tp_probes, probes[0]);
+
+		/*
+		 * We can't free probes if SRCU is not initialized yet.
+		 * Postpone the freeing till after SRCU is initialized.
+		 */
+		if (unlikely(!ok_to_free_tracepoints)) {
+			tp_probes->rcu.next = early_probes;
+			early_probes = &tp_probes->rcu;
+			return;
+		}
+
+		/*
+		 * Tracepoint probes are protected by both sched RCU and SRCU,
+		 * by calling the SRCU callback in the sched RCU callback we
+		 * cover both cases. So let us chain the SRCU and sched RCU
+		 * callbacks to wait for both grace periods.
+		 */
+		call_rcu(&tp_probes->rcu, rcu_free_old_probes);
+	}
+}
+
+static void debug_print_probes(struct tracepoint_func *funcs)
+{
+	int i;
+
+	if (!tracepoint_debug || !funcs)
+		return;
+
+	for (i = 0; funcs[i].func; i++)
+		printk(KERN_DEBUG "Probe %d : %p\n", i, funcs[i].func);
+}
+
+static struct tracepoint_func *
+func_add(struct tracepoint_func **funcs, struct tracepoint_func *tp_func,
+	 int prio)
+{
+	struct tracepoint_func *old, *new;
+	int iter_probes;	/* Iterate over old probe array. */
+	int nr_probes = 0;	/* Counter for probes */
+	int pos = -1;		/* Insertion position into new array */
+
+	if (WARN_ON(!tp_func->func))
+		return ERR_PTR(-EINVAL);
+
+	debug_print_probes(*funcs);
+	old = *funcs;
+	if (old) {
+		/* (N -> N+1), (N != 0, 1) probes */
+		for (iter_probes = 0; old[iter_probes].func; iter_probes++) {
+			if (old[iter_probes].func == tp_stub_func)
+				continue;	/* Skip stub functions. */
+			if (old[iter_probes].func == tp_func->func &&
+			    old[iter_probes].data == tp_func->data)
+				return ERR_PTR(-EEXIST);
+			nr_probes++;
+		}
+	}
+	/* + 2 : one for new probe, one for NULL func */
+	new = allocate_probes(nr_probes + 2);
+	if (new == NULL)
+		return ERR_PTR(-ENOMEM);
+	if (old) {
+		nr_probes = 0;
+		for (iter_probes = 0; old[iter_probes].func; iter_probes++) {
+			if (old[iter_probes].func == tp_stub_func)
+				continue;
+			/* Insert before probes of lower priority */
+			if (pos < 0 && old[iter_probes].prio < prio)
+				pos = nr_probes++;
+			new[nr_probes++] = old[iter_probes];
+		}
+		if (pos < 0)
+			pos = nr_probes++;
+		/* nr_probes now points to the end of the new array */
+	} else {
+		pos = 0;
+		nr_probes = 1; /* must point at end of array */
+	}
+	new[pos] = *tp_func;
+	new[nr_probes].func = NULL;
+	*funcs = new;
+	debug_print_probes(*funcs);
+	return old;
+}
+
+static void *func_remove(struct tracepoint_func **funcs,
+		struct tracepoint_func *tp_func)
+{
+	int nr_probes = 0, nr_del = 0, i;
+	struct tracepoint_func *old, *new;
+
+	old = *funcs;
+
+	if (!old)
+		return ERR_PTR(-ENOENT);
+
+	debug_print_probes(*funcs);
+	/* (N -> M), (N > 1, M >= 0) probes */
+	if (tp_func->func) {
+		for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
+			if ((old[nr_probes].func == tp_func->func &&
+			     old[nr_probes].data == tp_func->data) ||
+			    old[nr_probes].func == tp_stub_func)
+				nr_del++;
+		}
+	}
+
+	/*
+	 * If probe is NULL, then nr_probes = nr_del = 0, and then the
+	 * entire entry will be removed.
+	 */
+	if (nr_probes - nr_del == 0) {
+		/* N -> 0, (N > 1) */
+		*funcs = NULL;
+		debug_print_probes(*funcs);
+		return old;
+	} else {
+		int j = 0;
+		/* N -> M, (N > 1, M > 0) */
+		/* + 1 for NULL */
+		new = allocate_probes(nr_probes - nr_del + 1);
+		if (new) {
+			for (i = 0; old[i].func; i++) {
+				if ((old[i].func != tp_func->func ||
+				     old[i].data != tp_func->data) &&
+				    old[i].func != tp_stub_func)
+					new[j++] = old[i];
+			}
+			new[nr_probes - nr_del].func = NULL;
+			*funcs = new;
+		} else {
+			/*
+			 * Failed to allocate, replace the old function
+			 * with calls to tp_stub_func.
+			 */
+			for (i = 0; old[i].func; i++) {
+				if (old[i].func == tp_func->func &&
+				    old[i].data == tp_func->data)
+					WRITE_ONCE(old[i].func, tp_stub_func);
+			}
+			*funcs = old;
+		}
+	}
+	debug_print_probes(*funcs);
+	return old;
+}
+
+/*
+ * Count the number of functions (enum tp_func_state) in a tp_funcs array.
+ */
+static enum tp_func_state nr_func_state(const struct tracepoint_func *tp_funcs)
+{
+	if (!tp_funcs)
+		return TP_FUNC_0;
+	if (!tp_funcs[1].func)
+		return TP_FUNC_1;
+	if (!tp_funcs[2].func)
+		return TP_FUNC_2;
+	return TP_FUNC_N;	/* 3 or more */
+}
+
+static void tracepoint_update_call(struct tracepoint *tp, struct tracepoint_func *tp_funcs)
+{
+	void *func = tp->iterator;
+
+	/* Synthetic events do not have static call sites */
+	if (!tp->static_call_key)
+		return;
+	if (nr_func_state(tp_funcs) == TP_FUNC_1)
+		func = tp_funcs[0].func;
+	__static_call_update(tp->static_call_key, tp->static_call_tramp, func);
+}
+
+/*
+ * Add the probe function to a tracepoint.
+ */
+static int tracepoint_add_func(struct tracepoint *tp,
+			       struct tracepoint_func *func, int prio,
+			       bool warn)
+{
+	struct tracepoint_func *old, *tp_funcs;
+	int ret;
+
+	if (tp->regfunc && !static_key_enabled(&tp->key)) {
+		ret = tp->regfunc();
+		if (ret < 0)
+			return ret;
+	}
+
+	tp_funcs = rcu_dereference_protected(tp->funcs,
+			lockdep_is_held(&tracepoints_mutex));
+	old = func_add(&tp_funcs, func, prio);
+	if (IS_ERR(old)) {
+		WARN_ON_ONCE(warn && PTR_ERR(old) != -ENOMEM);
+		return PTR_ERR(old);
+	}
+
+	/*
+	 * rcu_assign_pointer has as smp_store_release() which makes sure
+	 * that the new probe callbacks array is consistent before setting
+	 * a pointer to it.  This array is referenced by __DO_TRACE from
+	 * include/linux/tracepoint.h using rcu_dereference_sched().
+	 */
+	switch (nr_func_state(tp_funcs)) {
+	case TP_FUNC_1:		/* 0->1 */
+		/*
+		 * Make sure new static func never uses old data after a
+		 * 1->0->1 transition sequence.
+		 */
+		tp_rcu_cond_sync(TP_TRANSITION_SYNC_1_0_1);
+		/* Set static call to first function */
+		tracepoint_update_call(tp, tp_funcs);
+		/* Both iterator and static call handle NULL tp->funcs */
+		rcu_assign_pointer(tp->funcs, tp_funcs);
+		static_key_enable(&tp->key);
+		break;
+	case TP_FUNC_2:		/* 1->2 */
+		/* Set iterator static call */
+		tracepoint_update_call(tp, tp_funcs);
+		/*
+		 * Iterator callback installed before updating tp->funcs.
+		 * Requires ordering between RCU assign/dereference and
+		 * static call update/call.
+		 */
+		fallthrough;
+	case TP_FUNC_N:		/* N->N+1 (N>1) */
+		rcu_assign_pointer(tp->funcs, tp_funcs);
+		/*
+		 * Make sure static func never uses incorrect data after a
+		 * N->...->2->1 (N>1) transition sequence.
+		 */
+		if (tp_funcs[0].data != old[0].data)
+			tp_rcu_get_state(TP_TRANSITION_SYNC_N_2_1);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
+
+	release_probes(old);
+	return 0;
+}
+
+/*
+ * Remove a probe function from a tracepoint.
+ * Note: only waiting an RCU period after setting elem->call to the empty
+ * function insures that the original callback is not used anymore. This insured
+ * by preempt_disable around the call site.
+ */
+static int tracepoint_remove_func(struct tracepoint *tp,
+		struct tracepoint_func *func)
+{
+	struct tracepoint_func *old, *tp_funcs;
+
+	tp_funcs = rcu_dereference_protected(tp->funcs,
+			lockdep_is_held(&tracepoints_mutex));
+	old = func_remove(&tp_funcs, func);
+	if (WARN_ON_ONCE(IS_ERR(old)))
+		return PTR_ERR(old);
+
+	if (tp_funcs == old)
+		/* Failed allocating new tp_funcs, replaced func with stub */
+		return 0;
+
+	switch (nr_func_state(tp_funcs)) {
+	case TP_FUNC_0:		/* 1->0 */
+		/* Removed last function */
+		if (tp->unregfunc && static_key_enabled(&tp->key))
+			tp->unregfunc();
+
+		static_key_disable(&tp->key);
+		/* Set iterator static call */
+		tracepoint_update_call(tp, tp_funcs);
+		/* Both iterator and static call handle NULL tp->funcs */
+		rcu_assign_pointer(tp->funcs, NULL);
+		/*
+		 * Make sure new static func never uses old data after a
+		 * 1->0->1 transition sequence.
+		 */
+		tp_rcu_get_state(TP_TRANSITION_SYNC_1_0_1);
+		break;
+	case TP_FUNC_1:		/* 2->1 */
+		rcu_assign_pointer(tp->funcs, tp_funcs);
+		/*
+		 * Make sure static func never uses incorrect data after a
+		 * N->...->2->1 (N>2) transition sequence. If the first
+		 * element's data has changed, then force the synchronization
+		 * to prevent current readers that have loaded the old data
+		 * from calling the new function.
+		 */
+		if (tp_funcs[0].data != old[0].data)
+			tp_rcu_get_state(TP_TRANSITION_SYNC_N_2_1);
+		tp_rcu_cond_sync(TP_TRANSITION_SYNC_N_2_1);
+		/* Set static call to first function */
+		tracepoint_update_call(tp, tp_funcs);
+		break;
+	case TP_FUNC_2:		/* N->N-1 (N>2) */
+		fallthrough;
+	case TP_FUNC_N:
+		rcu_assign_pointer(tp->funcs, tp_funcs);
+		/*
+		 * Make sure static func never uses incorrect data after a
+		 * N->...->2->1 (N>2) transition sequence.
+		 */
+		if (tp_funcs[0].data != old[0].data)
+			tp_rcu_get_state(TP_TRANSITION_SYNC_N_2_1);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
+	release_probes(old);
+	return 0;
+}
+
+/**
+ * tracepoint_probe_register_prio_may_exist -  Connect a probe to a tracepoint with priority
+ * @tp: tracepoint
+ * @probe: probe handler
+ * @data: tracepoint data
+ * @prio: priority of this function over other registered functions
+ *
+ * Same as tracepoint_probe_register_prio() except that it will not warn
+ * if the tracepoint is already registered.
+ */
+int tracepoint_probe_register_prio_may_exist(struct tracepoint *tp, void *probe,
+					     void *data, int prio)
+{
+	struct tracepoint_func tp_func;
+	int ret;
+
+	mutex_lock(&tracepoints_mutex);
+	tp_func.func = probe;
+	tp_func.data = data;
+	tp_func.prio = prio;
+	ret = tracepoint_add_func(tp, &tp_func, prio, false);
+	mutex_unlock(&tracepoints_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tracepoint_probe_register_prio_may_exist);
+
+/**
+ * tracepoint_probe_register_prio -  Connect a probe to a tracepoint with priority
+ * @tp: tracepoint
+ * @probe: probe handler
+ * @data: tracepoint data
+ * @prio: priority of this function over other registered functions
+ *
+ * Returns 0 if ok, error value on error.
+ * Note: if @tp is within a module, the caller is responsible for
+ * unregistering the probe before the module is gone. This can be
+ * performed either with a tracepoint module going notifier, or from
+ * within module exit functions.
+ */
+int tracepoint_probe_register_prio(struct tracepoint *tp, void *probe,
+				   void *data, int prio)
+{
+	struct tracepoint_func tp_func;
+	int ret;
+
+	mutex_lock(&tracepoints_mutex);
+	tp_func.func = probe;
+	tp_func.data = data;
+	tp_func.prio = prio;
+	ret = tracepoint_add_func(tp, &tp_func, prio, true);
+	mutex_unlock(&tracepoints_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tracepoint_probe_register_prio);
+
+/**
+ * tracepoint_probe_register -  Connect a probe to a tracepoint
+ * @tp: tracepoint
+ * @probe: probe handler
+ * @data: tracepoint data
+ *
+ * Returns 0 if ok, error value on error.
+ * Note: if @tp is within a module, the caller is responsible for
+ * unregistering the probe before the module is gone. This can be
+ * performed either with a tracepoint module going notifier, or from
+ * within module exit functions.
+ */
+int tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data)
+{
+	return tracepoint_probe_register_prio(tp, probe, data, TRACEPOINT_DEFAULT_PRIO);
+}
+EXPORT_SYMBOL_GPL(tracepoint_probe_register);
+
+/**
+ * tracepoint_probe_unregister -  Disconnect a probe from a tracepoint
+ * @tp: tracepoint
+ * @probe: probe function pointer
+ * @data: tracepoint data
+ *
+ * Returns 0 if ok, error value on error.
+ */
+int tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data)
+{
+	struct tracepoint_func tp_func;
+	int ret;
+
+	mutex_lock(&tracepoints_mutex);
+	tp_func.func = probe;
+	tp_func.data = data;
+	ret = tracepoint_remove_func(tp, &tp_func);
+	mutex_unlock(&tracepoints_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
+
+static void for_each_tracepoint_range(
+		tracepoint_ptr_t *begin, tracepoint_ptr_t *end,
+		void (*fct)(struct tracepoint *tp, void *priv),
+		void *priv)
+{
+	tracepoint_ptr_t *iter;
+
+	if (!begin)
+		return;
+	for (iter = begin; iter < end; iter++)
+		fct(tracepoint_ptr_deref(iter), priv);
+}
+
+#ifdef CONFIG_MODULES
+bool trace_module_has_bad_taint(struct module *mod)
+{
+	return mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP) |
+			       (1 << TAINT_UNSIGNED_MODULE) |
+			       (1 << TAINT_TEST));
+}
+
+static BLOCKING_NOTIFIER_HEAD(tracepoint_notify_list);
+
+/**
+ * register_tracepoint_module_notifier - register tracepoint coming/going notifier
+ * @nb: notifier block
+ *
+ * Notifiers registered with this function are called on module
+ * coming/going with the tracepoint_module_list_mutex held.
+ * The notifier block callback should expect a "struct tp_module" data
+ * pointer.
+ */
+int register_tracepoint_module_notifier(struct notifier_block *nb)
+{
+	struct tp_module *tp_mod;
+	int ret;
+
+	mutex_lock(&tracepoint_module_list_mutex);
+	ret = blocking_notifier_chain_register(&tracepoint_notify_list, nb);
+	if (ret)
+		goto end;
+	list_for_each_entry(tp_mod, &tracepoint_module_list, list)
+		(void) nb->notifier_call(nb, MODULE_STATE_COMING, tp_mod);
+end:
+	mutex_unlock(&tracepoint_module_list_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_tracepoint_module_notifier);
+
+/**
+ * unregister_tracepoint_module_notifier - unregister tracepoint coming/going notifier
+ * @nb: notifier block
+ *
+ * The notifier block callback should expect a "struct tp_module" data
+ * pointer.
+ */
+int unregister_tracepoint_module_notifier(struct notifier_block *nb)
+{
+	struct tp_module *tp_mod;
+	int ret;
+
+	mutex_lock(&tracepoint_module_list_mutex);
+	ret = blocking_notifier_chain_unregister(&tracepoint_notify_list, nb);
+	if (ret)
+		goto end;
+	list_for_each_entry(tp_mod, &tracepoint_module_list, list)
+		(void) nb->notifier_call(nb, MODULE_STATE_GOING, tp_mod);
+end:
+	mutex_unlock(&tracepoint_module_list_mutex);
+	return ret;
+
+}
+EXPORT_SYMBOL_GPL(unregister_tracepoint_module_notifier);
+
+/*
+ * Ensure the tracer unregistered the module's probes before the module
+ * teardown is performed. Prevents leaks of probe and data pointers.
+ */
+static void tp_module_going_check_quiescent(struct tracepoint *tp, void *priv)
+{
+	WARN_ON_ONCE(tp->funcs);
+}
+
+static int tracepoint_module_coming(struct module *mod)
+{
+	struct tp_module *tp_mod;
+
+	if (!mod->num_tracepoints)
+		return 0;
+
+	/*
+	 * We skip modules that taint the kernel, especially those with different
+	 * module headers (for forced load), to make sure we don't cause a crash.
+	 * Staging, out-of-tree, unsigned GPL, and test modules are fine.
+	 */
+	if (trace_module_has_bad_taint(mod))
+		return 0;
+
+	tp_mod = kmalloc(sizeof(struct tp_module), GFP_KERNEL);
+	if (!tp_mod)
+		return -ENOMEM;
+	tp_mod->mod = mod;
+
+	mutex_lock(&tracepoint_module_list_mutex);
+	list_add_tail(&tp_mod->list, &tracepoint_module_list);
+	blocking_notifier_call_chain(&tracepoint_notify_list,
+			MODULE_STATE_COMING, tp_mod);
+	mutex_unlock(&tracepoint_module_list_mutex);
+	return 0;
+}
+
+static void tracepoint_module_going(struct module *mod)
+{
+	struct tp_module *tp_mod;
+
+	if (!mod->num_tracepoints)
+		return;
+
+	mutex_lock(&tracepoint_module_list_mutex);
+	list_for_each_entry(tp_mod, &tracepoint_module_list, list) {
+		if (tp_mod->mod == mod) {
+			blocking_notifier_call_chain(&tracepoint_notify_list,
+					MODULE_STATE_GOING, tp_mod);
+			list_del(&tp_mod->list);
+			kfree(tp_mod);
+			/*
+			 * Called the going notifier before checking for
+			 * quiescence.
+			 */
+			for_each_tracepoint_range(mod->tracepoints_ptrs,
+				mod->tracepoints_ptrs + mod->num_tracepoints,
+				tp_module_going_check_quiescent, NULL);
+			break;
+		}
+	}
+	/*
+	 * In the case of modules that were tainted at "coming", we'll simply
+	 * walk through the list without finding it. We cannot use the "tainted"
+	 * flag on "going", in case a module taints the kernel only after being
+	 * loaded.
+	 */
+	mutex_unlock(&tracepoint_module_list_mutex);
+}
+
+static int tracepoint_module_notify(struct notifier_block *self,
+		unsigned long val, void *data)
+{
+	struct module *mod = data;
+	int ret = 0;
+
+	switch (val) {
+	case MODULE_STATE_COMING:
+		ret = tracepoint_module_coming(mod);
+		break;
+	case MODULE_STATE_LIVE:
+		break;
+	case MODULE_STATE_GOING:
+		tracepoint_module_going(mod);
+		break;
+	case MODULE_STATE_UNFORMED:
+		break;
+	}
+	return notifier_from_errno(ret);
+}
+
+static struct notifier_block tracepoint_module_nb = {
+	.notifier_call = tracepoint_module_notify,
+	.priority = 0,
+};
+
+static __init int init_tracepoints(void)
+{
+	int ret;
+
+	ret = register_module_notifier(&tracepoint_module_nb);
+	if (ret)
+		pr_warn("Failed to register tracepoint module enter notifier\n");
+
+	return ret;
+}
+__initcall(init_tracepoints);
+#endif /* CONFIG_MODULES */
+
+/**
+ * for_each_kernel_tracepoint - iteration on all kernel tracepoints
+ * @fct: callback
+ * @priv: private data
+ */
+void for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
+		void *priv)
+{
+	for_each_tracepoint_range(__start___tracepoints_ptrs,
+		__stop___tracepoints_ptrs, fct, priv);
+}
+EXPORT_SYMBOL_GPL(for_each_kernel_tracepoint);
+
+#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
+
+/* NB: reg/unreg are called while guarded with the tracepoints_mutex */
+static int sys_tracepoint_refcount;
+
+int syscall_regfunc(void)
+{
+	struct task_struct *p, *t;
+
+	if (!sys_tracepoint_refcount) {
+		read_lock(&tasklist_lock);
+		for_each_process_thread(p, t) {
+			set_task_syscall_work(t, SYSCALL_TRACEPOINT);
+		}
+		read_unlock(&tasklist_lock);
+	}
+	sys_tracepoint_refcount++;
+
+	return 0;
+}
+
+void syscall_unregfunc(void)
+{
+	struct task_struct *p, *t;
+
+	sys_tracepoint_refcount--;
+	if (!sys_tracepoint_refcount) {
+		read_lock(&tasklist_lock);
+		for_each_process_thread(p, t) {
+			clear_task_syscall_work(t, SYSCALL_TRACEPOINT);
+		}
+		read_unlock(&tasklist_lock);
+	}
+}
+#endif
diff --git a/kernel/tsacct.c b/kernel/tsacct.c
new file mode 100644
index 000000000..4252f0645
--- /dev/null
+++ b/kernel/tsacct.c
@@ -0,0 +1,182 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * tsacct.c - System accounting over taskstats interface
+ *
+ * Copyright (C) Jay Lan,	<jlan@sgi.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/cputime.h>
+#include <linux/tsacct_kern.h>
+#include <linux/acct.h>
+#include <linux/jiffies.h>
+#include <linux/mm.h>
+
+/*
+ * fill in basic accounting fields
+ */
+void bacct_add_tsk(struct user_namespace *user_ns,
+		   struct pid_namespace *pid_ns,
+		   struct taskstats *stats, struct task_struct *tsk)
+{
+	const struct cred *tcred;
+	u64 utime, stime, utimescaled, stimescaled;
+	u64 now_ns, delta;
+	time64_t btime;
+
+	BUILD_BUG_ON(TS_COMM_LEN < TASK_COMM_LEN);
+
+	/* calculate task elapsed time in nsec */
+	now_ns = ktime_get_ns();
+	/* store whole group time first */
+	delta = now_ns - tsk->group_leader->start_time;
+	/* Convert to micro seconds */
+	do_div(delta, NSEC_PER_USEC);
+	stats->ac_tgetime = delta;
+	delta = now_ns - tsk->start_time;
+	do_div(delta, NSEC_PER_USEC);
+	stats->ac_etime = delta;
+	/* Convert to seconds for btime (note y2106 limit) */
+	btime = ktime_get_real_seconds() - div_u64(delta, USEC_PER_SEC);
+	stats->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX);
+	stats->ac_btime64 = btime;
+
+	if (tsk->flags & PF_EXITING)
+		stats->ac_exitcode = tsk->exit_code;
+	if (thread_group_leader(tsk) && (tsk->flags & PF_FORKNOEXEC))
+		stats->ac_flag |= AFORK;
+	if (tsk->flags & PF_SUPERPRIV)
+		stats->ac_flag |= ASU;
+	if (tsk->flags & PF_DUMPCORE)
+		stats->ac_flag |= ACORE;
+	if (tsk->flags & PF_SIGNALED)
+		stats->ac_flag |= AXSIG;
+	stats->ac_nice	 = task_nice(tsk);
+	stats->ac_sched	 = tsk->policy;
+	stats->ac_pid	 = task_pid_nr_ns(tsk, pid_ns);
+	stats->ac_tgid   = task_tgid_nr_ns(tsk, pid_ns);
+	rcu_read_lock();
+	tcred = __task_cred(tsk);
+	stats->ac_uid	 = from_kuid_munged(user_ns, tcred->uid);
+	stats->ac_gid	 = from_kgid_munged(user_ns, tcred->gid);
+	stats->ac_ppid	 = pid_alive(tsk) ?
+		task_tgid_nr_ns(rcu_dereference(tsk->real_parent), pid_ns) : 0;
+	rcu_read_unlock();
+
+	task_cputime(tsk, &utime, &stime);
+	stats->ac_utime = div_u64(utime, NSEC_PER_USEC);
+	stats->ac_stime = div_u64(stime, NSEC_PER_USEC);
+
+	task_cputime_scaled(tsk, &utimescaled, &stimescaled);
+	stats->ac_utimescaled = div_u64(utimescaled, NSEC_PER_USEC);
+	stats->ac_stimescaled = div_u64(stimescaled, NSEC_PER_USEC);
+
+	stats->ac_minflt = tsk->min_flt;
+	stats->ac_majflt = tsk->maj_flt;
+
+	strncpy(stats->ac_comm, tsk->comm, sizeof(stats->ac_comm));
+}
+
+
+#ifdef CONFIG_TASK_XACCT
+
+#define KB 1024
+#define MB (1024*KB)
+#define KB_MASK (~(KB-1))
+/*
+ * fill in extended accounting fields
+ */
+void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
+{
+	struct mm_struct *mm;
+
+	/* convert pages-nsec/1024 to Mbyte-usec, see __acct_update_integrals */
+	stats->coremem = p->acct_rss_mem1 * PAGE_SIZE;
+	do_div(stats->coremem, 1000 * KB);
+	stats->virtmem = p->acct_vm_mem1 * PAGE_SIZE;
+	do_div(stats->virtmem, 1000 * KB);
+	mm = get_task_mm(p);
+	if (mm) {
+		/* adjust to KB unit */
+		stats->hiwater_rss   = get_mm_hiwater_rss(mm) * PAGE_SIZE / KB;
+		stats->hiwater_vm    = get_mm_hiwater_vm(mm)  * PAGE_SIZE / KB;
+		mmput(mm);
+	}
+	stats->read_char	= p->ioac.rchar & KB_MASK;
+	stats->write_char	= p->ioac.wchar & KB_MASK;
+	stats->read_syscalls	= p->ioac.syscr & KB_MASK;
+	stats->write_syscalls	= p->ioac.syscw & KB_MASK;
+#ifdef CONFIG_TASK_IO_ACCOUNTING
+	stats->read_bytes	= p->ioac.read_bytes & KB_MASK;
+	stats->write_bytes	= p->ioac.write_bytes & KB_MASK;
+	stats->cancelled_write_bytes = p->ioac.cancelled_write_bytes & KB_MASK;
+#else
+	stats->read_bytes	= 0;
+	stats->write_bytes	= 0;
+	stats->cancelled_write_bytes = 0;
+#endif
+}
+#undef KB
+#undef MB
+
+static void __acct_update_integrals(struct task_struct *tsk,
+				    u64 utime, u64 stime)
+{
+	u64 time, delta;
+
+	if (!likely(tsk->mm))
+		return;
+
+	time = stime + utime;
+	delta = time - tsk->acct_timexpd;
+
+	if (delta < TICK_NSEC)
+		return;
+
+	tsk->acct_timexpd = time;
+	/*
+	 * Divide by 1024 to avoid overflow, and to avoid division.
+	 * The final unit reported to userspace is Mbyte-usecs,
+	 * the rest of the math is done in xacct_add_tsk.
+	 */
+	tsk->acct_rss_mem1 += delta * get_mm_rss(tsk->mm) >> 10;
+	tsk->acct_vm_mem1 += delta * READ_ONCE(tsk->mm->total_vm) >> 10;
+}
+
+/**
+ * acct_update_integrals - update mm integral fields in task_struct
+ * @tsk: task_struct for accounting
+ */
+void acct_update_integrals(struct task_struct *tsk)
+{
+	u64 utime, stime;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	task_cputime(tsk, &utime, &stime);
+	__acct_update_integrals(tsk, utime, stime);
+	local_irq_restore(flags);
+}
+
+/**
+ * acct_account_cputime - update mm integral after cputime update
+ * @tsk: task_struct for accounting
+ */
+void acct_account_cputime(struct task_struct *tsk)
+{
+	__acct_update_integrals(tsk, tsk->utime, tsk->stime);
+}
+
+/**
+ * acct_clear_integrals - clear the mm integral fields in task_struct
+ * @tsk: task_struct whose accounting fields are cleared
+ */
+void acct_clear_integrals(struct task_struct *tsk)
+{
+	tsk->acct_timexpd = 0;
+	tsk->acct_rss_mem1 = 0;
+	tsk->acct_vm_mem1 = 0;
+}
+#endif
diff --git a/kernel/ucount.c b/kernel/ucount.c
new file mode 100644
index 000000000..ee8e57fd6
--- /dev/null
+++ b/kernel/ucount.c
@@ -0,0 +1,376 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/stat.h>
+#include <linux/sysctl.h>
+#include <linux/slab.h>
+#include <linux/cred.h>
+#include <linux/hash.h>
+#include <linux/kmemleak.h>
+#include <linux/user_namespace.h>
+
+struct ucounts init_ucounts = {
+	.ns    = &init_user_ns,
+	.uid   = GLOBAL_ROOT_UID,
+	.count = ATOMIC_INIT(1),
+};
+
+#define UCOUNTS_HASHTABLE_BITS 10
+static struct hlist_head ucounts_hashtable[(1 << UCOUNTS_HASHTABLE_BITS)];
+static DEFINE_SPINLOCK(ucounts_lock);
+
+#define ucounts_hashfn(ns, uid)						\
+	hash_long((unsigned long)__kuid_val(uid) + (unsigned long)(ns), \
+		  UCOUNTS_HASHTABLE_BITS)
+#define ucounts_hashentry(ns, uid)	\
+	(ucounts_hashtable + ucounts_hashfn(ns, uid))
+
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table_set *
+set_lookup(struct ctl_table_root *root)
+{
+	return &current_user_ns()->set;
+}
+
+static int set_is_seen(struct ctl_table_set *set)
+{
+	return &current_user_ns()->set == set;
+}
+
+static int set_permissions(struct ctl_table_header *head,
+				  struct ctl_table *table)
+{
+	struct user_namespace *user_ns =
+		container_of(head->set, struct user_namespace, set);
+	int mode;
+
+	/* Allow users with CAP_SYS_RESOURCE unrestrained access */
+	if (ns_capable(user_ns, CAP_SYS_RESOURCE))
+		mode = (table->mode & S_IRWXU) >> 6;
+	else
+	/* Allow all others at most read-only access */
+		mode = table->mode & S_IROTH;
+	return (mode << 6) | (mode << 3) | mode;
+}
+
+static struct ctl_table_root set_root = {
+	.lookup = set_lookup,
+	.permissions = set_permissions,
+};
+
+static long ue_zero = 0;
+static long ue_int_max = INT_MAX;
+
+#define UCOUNT_ENTRY(name)					\
+	{							\
+		.procname	= name,				\
+		.maxlen		= sizeof(long),			\
+		.mode		= 0644,				\
+		.proc_handler	= proc_doulongvec_minmax,	\
+		.extra1		= &ue_zero,			\
+		.extra2		= &ue_int_max,			\
+	}
+static struct ctl_table user_table[] = {
+	UCOUNT_ENTRY("max_user_namespaces"),
+	UCOUNT_ENTRY("max_pid_namespaces"),
+	UCOUNT_ENTRY("max_uts_namespaces"),
+	UCOUNT_ENTRY("max_ipc_namespaces"),
+	UCOUNT_ENTRY("max_net_namespaces"),
+	UCOUNT_ENTRY("max_mnt_namespaces"),
+	UCOUNT_ENTRY("max_cgroup_namespaces"),
+	UCOUNT_ENTRY("max_time_namespaces"),
+#ifdef CONFIG_INOTIFY_USER
+	UCOUNT_ENTRY("max_inotify_instances"),
+	UCOUNT_ENTRY("max_inotify_watches"),
+#endif
+#ifdef CONFIG_FANOTIFY
+	UCOUNT_ENTRY("max_fanotify_groups"),
+	UCOUNT_ENTRY("max_fanotify_marks"),
+#endif
+	{ }
+};
+#endif /* CONFIG_SYSCTL */
+
+bool setup_userns_sysctls(struct user_namespace *ns)
+{
+#ifdef CONFIG_SYSCTL
+	struct ctl_table *tbl;
+
+	BUILD_BUG_ON(ARRAY_SIZE(user_table) != UCOUNT_COUNTS + 1);
+	setup_sysctl_set(&ns->set, &set_root, set_is_seen);
+	tbl = kmemdup(user_table, sizeof(user_table), GFP_KERNEL);
+	if (tbl) {
+		int i;
+		for (i = 0; i < UCOUNT_COUNTS; i++) {
+			tbl[i].data = &ns->ucount_max[i];
+		}
+		ns->sysctls = __register_sysctl_table(&ns->set, "user", tbl);
+	}
+	if (!ns->sysctls) {
+		kfree(tbl);
+		retire_sysctl_set(&ns->set);
+		return false;
+	}
+#endif
+	return true;
+}
+
+void retire_userns_sysctls(struct user_namespace *ns)
+{
+#ifdef CONFIG_SYSCTL
+	struct ctl_table *tbl;
+
+	tbl = ns->sysctls->ctl_table_arg;
+	unregister_sysctl_table(ns->sysctls);
+	retire_sysctl_set(&ns->set);
+	kfree(tbl);
+#endif
+}
+
+static struct ucounts *find_ucounts(struct user_namespace *ns, kuid_t uid, struct hlist_head *hashent)
+{
+	struct ucounts *ucounts;
+
+	hlist_for_each_entry(ucounts, hashent, node) {
+		if (uid_eq(ucounts->uid, uid) && (ucounts->ns == ns))
+			return ucounts;
+	}
+	return NULL;
+}
+
+static void hlist_add_ucounts(struct ucounts *ucounts)
+{
+	struct hlist_head *hashent = ucounts_hashentry(ucounts->ns, ucounts->uid);
+	spin_lock_irq(&ucounts_lock);
+	hlist_add_head(&ucounts->node, hashent);
+	spin_unlock_irq(&ucounts_lock);
+}
+
+static inline bool get_ucounts_or_wrap(struct ucounts *ucounts)
+{
+	/* Returns true on a successful get, false if the count wraps. */
+	return !atomic_add_negative(1, &ucounts->count);
+}
+
+struct ucounts *get_ucounts(struct ucounts *ucounts)
+{
+	if (!get_ucounts_or_wrap(ucounts)) {
+		put_ucounts(ucounts);
+		ucounts = NULL;
+	}
+	return ucounts;
+}
+
+struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid)
+{
+	struct hlist_head *hashent = ucounts_hashentry(ns, uid);
+	struct ucounts *ucounts, *new;
+	bool wrapped;
+
+	spin_lock_irq(&ucounts_lock);
+	ucounts = find_ucounts(ns, uid, hashent);
+	if (!ucounts) {
+		spin_unlock_irq(&ucounts_lock);
+
+		new = kzalloc(sizeof(*new), GFP_KERNEL);
+		if (!new)
+			return NULL;
+
+		new->ns = ns;
+		new->uid = uid;
+		atomic_set(&new->count, 1);
+
+		spin_lock_irq(&ucounts_lock);
+		ucounts = find_ucounts(ns, uid, hashent);
+		if (ucounts) {
+			kfree(new);
+		} else {
+			hlist_add_head(&new->node, hashent);
+			get_user_ns(new->ns);
+			spin_unlock_irq(&ucounts_lock);
+			return new;
+		}
+	}
+	wrapped = !get_ucounts_or_wrap(ucounts);
+	spin_unlock_irq(&ucounts_lock);
+	if (wrapped) {
+		put_ucounts(ucounts);
+		return NULL;
+	}
+	return ucounts;
+}
+
+void put_ucounts(struct ucounts *ucounts)
+{
+	unsigned long flags;
+
+	if (atomic_dec_and_lock_irqsave(&ucounts->count, &ucounts_lock, flags)) {
+		hlist_del_init(&ucounts->node);
+		spin_unlock_irqrestore(&ucounts_lock, flags);
+		put_user_ns(ucounts->ns);
+		kfree(ucounts);
+	}
+}
+
+static inline bool atomic_long_inc_below(atomic_long_t *v, int u)
+{
+	long c, old;
+	c = atomic_long_read(v);
+	for (;;) {
+		if (unlikely(c >= u))
+			return false;
+		old = atomic_long_cmpxchg(v, c, c+1);
+		if (likely(old == c))
+			return true;
+		c = old;
+	}
+}
+
+struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid,
+			   enum ucount_type type)
+{
+	struct ucounts *ucounts, *iter, *bad;
+	struct user_namespace *tns;
+	ucounts = alloc_ucounts(ns, uid);
+	for (iter = ucounts; iter; iter = tns->ucounts) {
+		long max;
+		tns = iter->ns;
+		max = READ_ONCE(tns->ucount_max[type]);
+		if (!atomic_long_inc_below(&iter->ucount[type], max))
+			goto fail;
+	}
+	return ucounts;
+fail:
+	bad = iter;
+	for (iter = ucounts; iter != bad; iter = iter->ns->ucounts)
+		atomic_long_dec(&iter->ucount[type]);
+
+	put_ucounts(ucounts);
+	return NULL;
+}
+
+void dec_ucount(struct ucounts *ucounts, enum ucount_type type)
+{
+	struct ucounts *iter;
+	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
+		long dec = atomic_long_dec_if_positive(&iter->ucount[type]);
+		WARN_ON_ONCE(dec < 0);
+	}
+	put_ucounts(ucounts);
+}
+
+long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
+{
+	struct ucounts *iter;
+	long max = LONG_MAX;
+	long ret = 0;
+
+	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
+		long new = atomic_long_add_return(v, &iter->rlimit[type]);
+		if (new < 0 || new > max)
+			ret = LONG_MAX;
+		else if (iter == ucounts)
+			ret = new;
+		max = get_userns_rlimit_max(iter->ns, type);
+	}
+	return ret;
+}
+
+bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
+{
+	struct ucounts *iter;
+	long new = -1; /* Silence compiler warning */
+	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
+		long dec = atomic_long_sub_return(v, &iter->rlimit[type]);
+		WARN_ON_ONCE(dec < 0);
+		if (iter == ucounts)
+			new = dec;
+	}
+	return (new == 0);
+}
+
+static void do_dec_rlimit_put_ucounts(struct ucounts *ucounts,
+				struct ucounts *last, enum rlimit_type type)
+{
+	struct ucounts *iter, *next;
+	for (iter = ucounts; iter != last; iter = next) {
+		long dec = atomic_long_sub_return(1, &iter->rlimit[type]);
+		WARN_ON_ONCE(dec < 0);
+		next = iter->ns->ucounts;
+		if (dec == 0)
+			put_ucounts(iter);
+	}
+}
+
+void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type)
+{
+	do_dec_rlimit_put_ucounts(ucounts, NULL, type);
+}
+
+long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type)
+{
+	/* Caller must hold a reference to ucounts */
+	struct ucounts *iter;
+	long max = LONG_MAX;
+	long dec, ret = 0;
+
+	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
+		long new = atomic_long_add_return(1, &iter->rlimit[type]);
+		if (new < 0 || new > max)
+			goto unwind;
+		if (iter == ucounts)
+			ret = new;
+		max = get_userns_rlimit_max(iter->ns, type);
+		/*
+		 * Grab an extra ucount reference for the caller when
+		 * the rlimit count was previously 0.
+		 */
+		if (new != 1)
+			continue;
+		if (!get_ucounts(iter))
+			goto dec_unwind;
+	}
+	return ret;
+dec_unwind:
+	dec = atomic_long_sub_return(1, &iter->rlimit[type]);
+	WARN_ON_ONCE(dec < 0);
+unwind:
+	do_dec_rlimit_put_ucounts(ucounts, iter, type);
+	return 0;
+}
+
+bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long rlimit)
+{
+	struct ucounts *iter;
+	long max = rlimit;
+	if (rlimit > LONG_MAX)
+		max = LONG_MAX;
+	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
+		long val = get_rlimit_value(iter, type);
+		if (val < 0 || val > max)
+			return true;
+		max = get_userns_rlimit_max(iter->ns, type);
+	}
+	return false;
+}
+
+static __init int user_namespace_sysctl_init(void)
+{
+#ifdef CONFIG_SYSCTL
+	static struct ctl_table_header *user_header;
+	static struct ctl_table empty[1];
+	/*
+	 * It is necessary to register the user directory in the
+	 * default set so that registrations in the child sets work
+	 * properly.
+	 */
+	user_header = register_sysctl("user", empty);
+	kmemleak_ignore(user_header);
+	BUG_ON(!user_header);
+	BUG_ON(!setup_userns_sysctls(&init_user_ns));
+#endif
+	hlist_add_ucounts(&init_ucounts);
+	inc_rlimit_ucounts(&init_ucounts, UCOUNT_RLIMIT_NPROC, 1);
+	return 0;
+}
+subsys_initcall(user_namespace_sysctl_init);
diff --git a/kernel/uid16.c b/kernel/uid16.c
new file mode 100644
index 000000000..af6925d85
--- /dev/null
+++ b/kernel/uid16.c
@@ -0,0 +1,221 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *	Wrapper functions for 16bit uid back compatibility. All nicely tied
+ *	together in the faint hope we can take the out in five years time.
+ */
+
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/prctl.h>
+#include <linux/capability.h>
+#include <linux/init.h>
+#include <linux/highuid.h>
+#include <linux/security.h>
+#include <linux/cred.h>
+#include <linux/syscalls.h>
+
+#include <linux/uaccess.h>
+
+#include "uid16.h"
+
+SYSCALL_DEFINE3(chown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
+{
+	return ksys_chown(filename, low2highuid(user), low2highgid(group));
+}
+
+SYSCALL_DEFINE3(lchown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
+{
+	return ksys_lchown(filename, low2highuid(user), low2highgid(group));
+}
+
+SYSCALL_DEFINE3(fchown16, unsigned int, fd, old_uid_t, user, old_gid_t, group)
+{
+	return ksys_fchown(fd, low2highuid(user), low2highgid(group));
+}
+
+SYSCALL_DEFINE2(setregid16, old_gid_t, rgid, old_gid_t, egid)
+{
+	return __sys_setregid(low2highgid(rgid), low2highgid(egid));
+}
+
+SYSCALL_DEFINE1(setgid16, old_gid_t, gid)
+{
+	return __sys_setgid(low2highgid(gid));
+}
+
+SYSCALL_DEFINE2(setreuid16, old_uid_t, ruid, old_uid_t, euid)
+{
+	return __sys_setreuid(low2highuid(ruid), low2highuid(euid));
+}
+
+SYSCALL_DEFINE1(setuid16, old_uid_t, uid)
+{
+	return __sys_setuid(low2highuid(uid));
+}
+
+SYSCALL_DEFINE3(setresuid16, old_uid_t, ruid, old_uid_t, euid, old_uid_t, suid)
+{
+	return __sys_setresuid(low2highuid(ruid), low2highuid(euid),
+				 low2highuid(suid));
+}
+
+SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruidp, old_uid_t __user *, euidp, old_uid_t __user *, suidp)
+{
+	const struct cred *cred = current_cred();
+	int retval;
+	old_uid_t ruid, euid, suid;
+
+	ruid = high2lowuid(from_kuid_munged(cred->user_ns, cred->uid));
+	euid = high2lowuid(from_kuid_munged(cred->user_ns, cred->euid));
+	suid = high2lowuid(from_kuid_munged(cred->user_ns, cred->suid));
+
+	if (!(retval   = put_user(ruid, ruidp)) &&
+	    !(retval   = put_user(euid, euidp)))
+		retval = put_user(suid, suidp);
+
+	return retval;
+}
+
+SYSCALL_DEFINE3(setresgid16, old_gid_t, rgid, old_gid_t, egid, old_gid_t, sgid)
+{
+	return __sys_setresgid(low2highgid(rgid), low2highgid(egid),
+				 low2highgid(sgid));
+}
+
+SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgidp, old_gid_t __user *, egidp, old_gid_t __user *, sgidp)
+{
+	const struct cred *cred = current_cred();
+	int retval;
+	old_gid_t rgid, egid, sgid;
+
+	rgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->gid));
+	egid = high2lowgid(from_kgid_munged(cred->user_ns, cred->egid));
+	sgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->sgid));
+
+	if (!(retval   = put_user(rgid, rgidp)) &&
+	    !(retval   = put_user(egid, egidp)))
+		retval = put_user(sgid, sgidp);
+
+	return retval;
+}
+
+SYSCALL_DEFINE1(setfsuid16, old_uid_t, uid)
+{
+	return __sys_setfsuid(low2highuid(uid));
+}
+
+SYSCALL_DEFINE1(setfsgid16, old_gid_t, gid)
+{
+	return __sys_setfsgid(low2highgid(gid));
+}
+
+static int groups16_to_user(old_gid_t __user *grouplist,
+    struct group_info *group_info)
+{
+	struct user_namespace *user_ns = current_user_ns();
+	int i;
+	old_gid_t group;
+	kgid_t kgid;
+
+	for (i = 0; i < group_info->ngroups; i++) {
+		kgid = group_info->gid[i];
+		group = high2lowgid(from_kgid_munged(user_ns, kgid));
+		if (put_user(group, grouplist+i))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+static int groups16_from_user(struct group_info *group_info,
+    old_gid_t __user *grouplist)
+{
+	struct user_namespace *user_ns = current_user_ns();
+	int i;
+	old_gid_t group;
+	kgid_t kgid;
+
+	for (i = 0; i < group_info->ngroups; i++) {
+		if (get_user(group, grouplist+i))
+			return  -EFAULT;
+
+		kgid = make_kgid(user_ns, low2highgid(group));
+		if (!gid_valid(kgid))
+			return -EINVAL;
+
+		group_info->gid[i] = kgid;
+	}
+
+	return 0;
+}
+
+SYSCALL_DEFINE2(getgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
+{
+	const struct cred *cred = current_cred();
+	int i;
+
+	if (gidsetsize < 0)
+		return -EINVAL;
+
+	i = cred->group_info->ngroups;
+	if (gidsetsize) {
+		if (i > gidsetsize) {
+			i = -EINVAL;
+			goto out;
+		}
+		if (groups16_to_user(grouplist, cred->group_info)) {
+			i = -EFAULT;
+			goto out;
+		}
+	}
+out:
+	return i;
+}
+
+SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
+{
+	struct group_info *group_info;
+	int retval;
+
+	if (!may_setgroups())
+		return -EPERM;
+	if ((unsigned)gidsetsize > NGROUPS_MAX)
+		return -EINVAL;
+
+	group_info = groups_alloc(gidsetsize);
+	if (!group_info)
+		return -ENOMEM;
+	retval = groups16_from_user(group_info, grouplist);
+	if (retval) {
+		put_group_info(group_info);
+		return retval;
+	}
+
+	groups_sort(group_info);
+	retval = set_current_groups(group_info);
+	put_group_info(group_info);
+
+	return retval;
+}
+
+SYSCALL_DEFINE0(getuid16)
+{
+	return high2lowuid(from_kuid_munged(current_user_ns(), current_uid()));
+}
+
+SYSCALL_DEFINE0(geteuid16)
+{
+	return high2lowuid(from_kuid_munged(current_user_ns(), current_euid()));
+}
+
+SYSCALL_DEFINE0(getgid16)
+{
+	return high2lowgid(from_kgid_munged(current_user_ns(), current_gid()));
+}
+
+SYSCALL_DEFINE0(getegid16)
+{
+	return high2lowgid(from_kgid_munged(current_user_ns(), current_egid()));
+}
diff --git a/kernel/uid16.h b/kernel/uid16.h
new file mode 100644
index 000000000..cdca040f7
--- /dev/null
+++ b/kernel/uid16.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LINUX_UID16_H
+#define LINUX_UID16_H
+
+long __sys_setuid(uid_t uid);
+long __sys_setgid(gid_t gid);
+long __sys_setreuid(uid_t ruid, uid_t euid);
+long __sys_setregid(gid_t rgid, gid_t egid);
+long __sys_setresuid(uid_t ruid, uid_t euid, uid_t suid);
+long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid);
+long __sys_setfsuid(uid_t uid);
+long __sys_setfsgid(gid_t gid);
+
+#endif /* LINUX_UID16_H */
diff --git a/kernel/umh.c b/kernel/umh.c
new file mode 100644
index 000000000..fbf872c62
--- /dev/null
+++ b/kernel/umh.c
@@ -0,0 +1,576 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * umh - the kernel usermode helper
+ */
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/binfmts.h>
+#include <linux/syscalls.h>
+#include <linux/unistd.h>
+#include <linux/kmod.h>
+#include <linux/slab.h>
+#include <linux/completion.h>
+#include <linux/cred.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/fs_struct.h>
+#include <linux/workqueue.h>
+#include <linux/security.h>
+#include <linux/mount.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/resource.h>
+#include <linux/notifier.h>
+#include <linux/suspend.h>
+#include <linux/rwsem.h>
+#include <linux/ptrace.h>
+#include <linux/async.h>
+#include <linux/uaccess.h>
+#include <linux/initrd.h>
+#include <linux/freezer.h>
+
+#include <trace/events/module.h>
+
+#define CAP_BSET	(void *)1
+#define CAP_PI		(void *)2
+
+static kernel_cap_t usermodehelper_bset = CAP_FULL_SET;
+static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET;
+static DEFINE_SPINLOCK(umh_sysctl_lock);
+static DECLARE_RWSEM(umhelper_sem);
+
+static void call_usermodehelper_freeinfo(struct subprocess_info *info)
+{
+	if (info->cleanup)
+		(*info->cleanup)(info);
+	kfree(info);
+}
+
+static void umh_complete(struct subprocess_info *sub_info)
+{
+	struct completion *comp = xchg(&sub_info->complete, NULL);
+	/*
+	 * See call_usermodehelper_exec(). If xchg() returns NULL
+	 * we own sub_info, the UMH_KILLABLE caller has gone away
+	 * or the caller used UMH_NO_WAIT.
+	 */
+	if (comp)
+		complete(comp);
+	else
+		call_usermodehelper_freeinfo(sub_info);
+}
+
+/*
+ * This is the task which runs the usermode application
+ */
+static int call_usermodehelper_exec_async(void *data)
+{
+	struct subprocess_info *sub_info = data;
+	struct cred *new;
+	int retval;
+
+	spin_lock_irq(&current->sighand->siglock);
+	flush_signal_handlers(current, 1);
+	spin_unlock_irq(&current->sighand->siglock);
+
+	/*
+	 * Initial kernel threads share ther FS with init, in order to
+	 * get the init root directory. But we've now created a new
+	 * thread that is going to execve a user process and has its own
+	 * 'struct fs_struct'. Reset umask to the default.
+	 */
+	current->fs->umask = 0022;
+
+	/*
+	 * Our parent (unbound workqueue) runs with elevated scheduling
+	 * priority. Avoid propagating that into the userspace child.
+	 */
+	set_user_nice(current, 0);
+
+	retval = -ENOMEM;
+	new = prepare_kernel_cred(current);
+	if (!new)
+		goto out;
+
+	spin_lock(&umh_sysctl_lock);
+	new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset);
+	new->cap_inheritable = cap_intersect(usermodehelper_inheritable,
+					     new->cap_inheritable);
+	spin_unlock(&umh_sysctl_lock);
+
+	if (sub_info->init) {
+		retval = sub_info->init(sub_info, new);
+		if (retval) {
+			abort_creds(new);
+			goto out;
+		}
+	}
+
+	commit_creds(new);
+
+	wait_for_initramfs();
+	retval = kernel_execve(sub_info->path,
+			       (const char *const *)sub_info->argv,
+			       (const char *const *)sub_info->envp);
+out:
+	sub_info->retval = retval;
+	/*
+	 * call_usermodehelper_exec_sync() will call umh_complete
+	 * if UHM_WAIT_PROC.
+	 */
+	if (!(sub_info->wait & UMH_WAIT_PROC))
+		umh_complete(sub_info);
+	if (!retval)
+		return 0;
+	do_exit(0);
+}
+
+/* Handles UMH_WAIT_PROC.  */
+static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info)
+{
+	pid_t pid;
+
+	/* If SIGCLD is ignored do_wait won't populate the status. */
+	kernel_sigaction(SIGCHLD, SIG_DFL);
+	pid = user_mode_thread(call_usermodehelper_exec_async, sub_info, SIGCHLD);
+	if (pid < 0)
+		sub_info->retval = pid;
+	else
+		kernel_wait(pid, &sub_info->retval);
+
+	/* Restore default kernel sig handler */
+	kernel_sigaction(SIGCHLD, SIG_IGN);
+	umh_complete(sub_info);
+}
+
+/*
+ * We need to create the usermodehelper kernel thread from a task that is affine
+ * to an optimized set of CPUs (or nohz housekeeping ones) such that they
+ * inherit a widest affinity irrespective of call_usermodehelper() callers with
+ * possibly reduced affinity (eg: per-cpu workqueues). We don't want
+ * usermodehelper targets to contend a busy CPU.
+ *
+ * Unbound workqueues provide such wide affinity and allow to block on
+ * UMH_WAIT_PROC requests without blocking pending request (up to some limit).
+ *
+ * Besides, workqueues provide the privilege level that caller might not have
+ * to perform the usermodehelper request.
+ *
+ */
+static void call_usermodehelper_exec_work(struct work_struct *work)
+{
+	struct subprocess_info *sub_info =
+		container_of(work, struct subprocess_info, work);
+
+	if (sub_info->wait & UMH_WAIT_PROC) {
+		call_usermodehelper_exec_sync(sub_info);
+	} else {
+		pid_t pid;
+		/*
+		 * Use CLONE_PARENT to reparent it to kthreadd; we do not
+		 * want to pollute current->children, and we need a parent
+		 * that always ignores SIGCHLD to ensure auto-reaping.
+		 */
+		pid = user_mode_thread(call_usermodehelper_exec_async, sub_info,
+				       CLONE_PARENT | SIGCHLD);
+		if (pid < 0) {
+			sub_info->retval = pid;
+			umh_complete(sub_info);
+		}
+	}
+}
+
+/*
+ * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY
+ * (used for preventing user land processes from being created after the user
+ * land has been frozen during a system-wide hibernation or suspend operation).
+ * Should always be manipulated under umhelper_sem acquired for write.
+ */
+static enum umh_disable_depth usermodehelper_disabled = UMH_DISABLED;
+
+/* Number of helpers running */
+static atomic_t running_helpers = ATOMIC_INIT(0);
+
+/*
+ * Wait queue head used by usermodehelper_disable() to wait for all running
+ * helpers to finish.
+ */
+static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq);
+
+/*
+ * Used by usermodehelper_read_lock_wait() to wait for usermodehelper_disabled
+ * to become 'false'.
+ */
+static DECLARE_WAIT_QUEUE_HEAD(usermodehelper_disabled_waitq);
+
+/*
+ * Time to wait for running_helpers to become zero before the setting of
+ * usermodehelper_disabled in usermodehelper_disable() fails
+ */
+#define RUNNING_HELPERS_TIMEOUT	(5 * HZ)
+
+int usermodehelper_read_trylock(void)
+{
+	DEFINE_WAIT(wait);
+	int ret = 0;
+
+	down_read(&umhelper_sem);
+	for (;;) {
+		prepare_to_wait(&usermodehelper_disabled_waitq, &wait,
+				TASK_INTERRUPTIBLE);
+		if (!usermodehelper_disabled)
+			break;
+
+		if (usermodehelper_disabled == UMH_DISABLED)
+			ret = -EAGAIN;
+
+		up_read(&umhelper_sem);
+
+		if (ret)
+			break;
+
+		schedule();
+		try_to_freeze();
+
+		down_read(&umhelper_sem);
+	}
+	finish_wait(&usermodehelper_disabled_waitq, &wait);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usermodehelper_read_trylock);
+
+long usermodehelper_read_lock_wait(long timeout)
+{
+	DEFINE_WAIT(wait);
+
+	if (timeout < 0)
+		return -EINVAL;
+
+	down_read(&umhelper_sem);
+	for (;;) {
+		prepare_to_wait(&usermodehelper_disabled_waitq, &wait,
+				TASK_UNINTERRUPTIBLE);
+		if (!usermodehelper_disabled)
+			break;
+
+		up_read(&umhelper_sem);
+
+		timeout = schedule_timeout(timeout);
+		if (!timeout)
+			break;
+
+		down_read(&umhelper_sem);
+	}
+	finish_wait(&usermodehelper_disabled_waitq, &wait);
+	return timeout;
+}
+EXPORT_SYMBOL_GPL(usermodehelper_read_lock_wait);
+
+void usermodehelper_read_unlock(void)
+{
+	up_read(&umhelper_sem);
+}
+EXPORT_SYMBOL_GPL(usermodehelper_read_unlock);
+
+/**
+ * __usermodehelper_set_disable_depth - Modify usermodehelper_disabled.
+ * @depth: New value to assign to usermodehelper_disabled.
+ *
+ * Change the value of usermodehelper_disabled (under umhelper_sem locked for
+ * writing) and wakeup tasks waiting for it to change.
+ */
+void __usermodehelper_set_disable_depth(enum umh_disable_depth depth)
+{
+	down_write(&umhelper_sem);
+	usermodehelper_disabled = depth;
+	wake_up(&usermodehelper_disabled_waitq);
+	up_write(&umhelper_sem);
+}
+
+/**
+ * __usermodehelper_disable - Prevent new helpers from being started.
+ * @depth: New value to assign to usermodehelper_disabled.
+ *
+ * Set usermodehelper_disabled to @depth and wait for running helpers to exit.
+ */
+int __usermodehelper_disable(enum umh_disable_depth depth)
+{
+	long retval;
+
+	if (!depth)
+		return -EINVAL;
+
+	down_write(&umhelper_sem);
+	usermodehelper_disabled = depth;
+	up_write(&umhelper_sem);
+
+	/*
+	 * From now on call_usermodehelper_exec() won't start any new
+	 * helpers, so it is sufficient if running_helpers turns out to
+	 * be zero at one point (it may be increased later, but that
+	 * doesn't matter).
+	 */
+	retval = wait_event_timeout(running_helpers_waitq,
+					atomic_read(&running_helpers) == 0,
+					RUNNING_HELPERS_TIMEOUT);
+	if (retval)
+		return 0;
+
+	__usermodehelper_set_disable_depth(UMH_ENABLED);
+	return -EAGAIN;
+}
+
+static void helper_lock(void)
+{
+	atomic_inc(&running_helpers);
+	smp_mb__after_atomic();
+}
+
+static void helper_unlock(void)
+{
+	if (atomic_dec_and_test(&running_helpers))
+		wake_up(&running_helpers_waitq);
+}
+
+/**
+ * call_usermodehelper_setup - prepare to call a usermode helper
+ * @path: path to usermode executable
+ * @argv: arg vector for process
+ * @envp: environment for process
+ * @gfp_mask: gfp mask for memory allocation
+ * @init: an init function
+ * @cleanup: a cleanup function
+ * @data: arbitrary context sensitive data
+ *
+ * Returns either %NULL on allocation failure, or a subprocess_info
+ * structure.  This should be passed to call_usermodehelper_exec to
+ * exec the process and free the structure.
+ *
+ * The init function is used to customize the helper process prior to
+ * exec.  A non-zero return code causes the process to error out, exit,
+ * and return the failure to the calling process
+ *
+ * The cleanup function is just before the subprocess_info is about to
+ * be freed.  This can be used for freeing the argv and envp.  The
+ * Function must be runnable in either a process context or the
+ * context in which call_usermodehelper_exec is called.
+ */
+struct subprocess_info *call_usermodehelper_setup(const char *path, char **argv,
+		char **envp, gfp_t gfp_mask,
+		int (*init)(struct subprocess_info *info, struct cred *new),
+		void (*cleanup)(struct subprocess_info *info),
+		void *data)
+{
+	struct subprocess_info *sub_info;
+	sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask);
+	if (!sub_info)
+		goto out;
+
+	INIT_WORK(&sub_info->work, call_usermodehelper_exec_work);
+
+#ifdef CONFIG_STATIC_USERMODEHELPER
+	sub_info->path = CONFIG_STATIC_USERMODEHELPER_PATH;
+#else
+	sub_info->path = path;
+#endif
+	sub_info->argv = argv;
+	sub_info->envp = envp;
+
+	sub_info->cleanup = cleanup;
+	sub_info->init = init;
+	sub_info->data = data;
+  out:
+	return sub_info;
+}
+EXPORT_SYMBOL(call_usermodehelper_setup);
+
+/**
+ * call_usermodehelper_exec - start a usermode application
+ * @sub_info: information about the subprocess
+ * @wait: wait for the application to finish and return status.
+ *        when UMH_NO_WAIT don't wait at all, but you get no useful error back
+ *        when the program couldn't be exec'ed. This makes it safe to call
+ *        from interrupt context.
+ *
+ * Runs a user-space application.  The application is started
+ * asynchronously if wait is not set, and runs as a child of system workqueues.
+ * (ie. it runs with full root capabilities and optimized affinity).
+ *
+ * Note: successful return value does not guarantee the helper was called at
+ * all. You can't rely on sub_info->{init,cleanup} being called even for
+ * UMH_WAIT_* wait modes as STATIC_USERMODEHELPER_PATH="" turns all helpers
+ * into a successful no-op.
+ */
+int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
+{
+	unsigned int state = TASK_UNINTERRUPTIBLE;
+	DECLARE_COMPLETION_ONSTACK(done);
+	int retval = 0;
+
+	if (!sub_info->path) {
+		call_usermodehelper_freeinfo(sub_info);
+		return -EINVAL;
+	}
+	helper_lock();
+	if (usermodehelper_disabled) {
+		retval = -EBUSY;
+		goto out;
+	}
+
+	/*
+	 * If there is no binary for us to call, then just return and get out of
+	 * here.  This allows us to set STATIC_USERMODEHELPER_PATH to "" and
+	 * disable all call_usermodehelper() calls.
+	 */
+	if (strlen(sub_info->path) == 0)
+		goto out;
+
+	/*
+	 * Set the completion pointer only if there is a waiter.
+	 * This makes it possible to use umh_complete to free
+	 * the data structure in case of UMH_NO_WAIT.
+	 */
+	sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done;
+	sub_info->wait = wait;
+
+	queue_work(system_unbound_wq, &sub_info->work);
+	if (wait == UMH_NO_WAIT)	/* task has freed sub_info */
+		goto unlock;
+
+	if (wait & UMH_FREEZABLE)
+		state |= TASK_FREEZABLE;
+
+	if (wait & UMH_KILLABLE) {
+		retval = wait_for_completion_state(&done, state | TASK_KILLABLE);
+		if (!retval)
+			goto wait_done;
+
+		/* umh_complete() will see NULL and free sub_info */
+		if (xchg(&sub_info->complete, NULL))
+			goto unlock;
+
+		/*
+		 * fallthrough; in case of -ERESTARTSYS now do uninterruptible
+		 * wait_for_completion_state(). Since umh_complete() shall call
+		 * complete() in a moment if xchg() above returned NULL, this
+		 * uninterruptible wait_for_completion_state() will not block
+		 * SIGKILL'ed processes for long.
+		 */
+	}
+	wait_for_completion_state(&done, state);
+
+wait_done:
+	retval = sub_info->retval;
+out:
+	call_usermodehelper_freeinfo(sub_info);
+unlock:
+	helper_unlock();
+	return retval;
+}
+EXPORT_SYMBOL(call_usermodehelper_exec);
+
+/**
+ * call_usermodehelper() - prepare and start a usermode application
+ * @path: path to usermode executable
+ * @argv: arg vector for process
+ * @envp: environment for process
+ * @wait: wait for the application to finish and return status.
+ *        when UMH_NO_WAIT don't wait at all, but you get no useful error back
+ *        when the program couldn't be exec'ed. This makes it safe to call
+ *        from interrupt context.
+ *
+ * This function is the equivalent to use call_usermodehelper_setup() and
+ * call_usermodehelper_exec().
+ */
+int call_usermodehelper(const char *path, char **argv, char **envp, int wait)
+{
+	struct subprocess_info *info;
+	gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
+
+	info = call_usermodehelper_setup(path, argv, envp, gfp_mask,
+					 NULL, NULL, NULL);
+	if (info == NULL)
+		return -ENOMEM;
+
+	return call_usermodehelper_exec(info, wait);
+}
+EXPORT_SYMBOL(call_usermodehelper);
+
+static int proc_cap_handler(struct ctl_table *table, int write,
+			 void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table t;
+	unsigned long cap_array[_KERNEL_CAPABILITY_U32S];
+	kernel_cap_t new_cap;
+	int err, i;
+
+	if (write && (!capable(CAP_SETPCAP) ||
+		      !capable(CAP_SYS_MODULE)))
+		return -EPERM;
+
+	/*
+	 * convert from the global kernel_cap_t to the ulong array to print to
+	 * userspace if this is a read.
+	 */
+	spin_lock(&umh_sysctl_lock);
+	for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++)  {
+		if (table->data == CAP_BSET)
+			cap_array[i] = usermodehelper_bset.cap[i];
+		else if (table->data == CAP_PI)
+			cap_array[i] = usermodehelper_inheritable.cap[i];
+		else
+			BUG();
+	}
+	spin_unlock(&umh_sysctl_lock);
+
+	t = *table;
+	t.data = &cap_array;
+
+	/*
+	 * actually read or write and array of ulongs from userspace.  Remember
+	 * these are least significant 32 bits first
+	 */
+	err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
+	if (err < 0)
+		return err;
+
+	/*
+	 * convert from the sysctl array of ulongs to the kernel_cap_t
+	 * internal representation
+	 */
+	for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++)
+		new_cap.cap[i] = cap_array[i];
+
+	/*
+	 * Drop everything not in the new_cap (but don't add things)
+	 */
+	if (write) {
+		spin_lock(&umh_sysctl_lock);
+		if (table->data == CAP_BSET)
+			usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap);
+		if (table->data == CAP_PI)
+			usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap);
+		spin_unlock(&umh_sysctl_lock);
+	}
+
+	return 0;
+}
+
+struct ctl_table usermodehelper_table[] = {
+	{
+		.procname	= "bset",
+		.data		= CAP_BSET,
+		.maxlen		= _KERNEL_CAPABILITY_U32S * sizeof(unsigned long),
+		.mode		= 0600,
+		.proc_handler	= proc_cap_handler,
+	},
+	{
+		.procname	= "inheritable",
+		.data		= CAP_PI,
+		.maxlen		= _KERNEL_CAPABILITY_U32S * sizeof(unsigned long),
+		.mode		= 0600,
+		.proc_handler	= proc_cap_handler,
+	},
+	{ }
+};
diff --git a/kernel/up.c b/kernel/up.c
new file mode 100644
index 000000000..a38b8b095
--- /dev/null
+++ b/kernel/up.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Uniprocessor-only support functions.  The counterpart to kernel/smp.c
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/smp.h>
+#include <linux/hypervisor.h>
+
+int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
+				int wait)
+{
+	unsigned long flags;
+
+	if (cpu != 0)
+		return -ENXIO;
+
+	local_irq_save(flags);
+	func(info);
+	local_irq_restore(flags);
+
+	return 0;
+}
+EXPORT_SYMBOL(smp_call_function_single);
+
+int smp_call_function_single_async(int cpu, struct __call_single_data *csd)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	csd->func(csd->info);
+	local_irq_restore(flags);
+	return 0;
+}
+EXPORT_SYMBOL(smp_call_function_single_async);
+
+/*
+ * Preemption is disabled here to make sure the cond_func is called under the
+ * same conditions in UP and SMP.
+ */
+void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
+			   void *info, bool wait, const struct cpumask *mask)
+{
+	unsigned long flags;
+
+	preempt_disable();
+	if ((!cond_func || cond_func(0, info)) && cpumask_test_cpu(0, mask)) {
+		local_irq_save(flags);
+		func(info);
+		local_irq_restore(flags);
+	}
+	preempt_enable();
+}
+EXPORT_SYMBOL(on_each_cpu_cond_mask);
+
+int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
+{
+	int ret;
+
+	if (cpu != 0)
+		return -ENXIO;
+
+	if (phys)
+		hypervisor_pin_vcpu(0);
+	ret = func(par);
+	if (phys)
+		hypervisor_pin_vcpu(-1);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(smp_call_on_cpu);
diff --git a/kernel/user-return-notifier.c b/kernel/user-return-notifier.c
new file mode 100644
index 000000000..870ecd7c6
--- /dev/null
+++ b/kernel/user-return-notifier.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/user-return-notifier.h>
+#include <linux/percpu.h>
+#include <linux/sched.h>
+#include <linux/export.h>
+
+static DEFINE_PER_CPU(struct hlist_head, return_notifier_list);
+
+/*
+ * Request a notification when the current cpu returns to userspace.  Must be
+ * called in atomic context.  The notifier will also be called in atomic
+ * context.
+ */
+void user_return_notifier_register(struct user_return_notifier *urn)
+{
+	set_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
+	hlist_add_head(&urn->link, this_cpu_ptr(&return_notifier_list));
+}
+EXPORT_SYMBOL_GPL(user_return_notifier_register);
+
+/*
+ * Removes a registered user return notifier.  Must be called from atomic
+ * context, and from the same cpu registration occurred in.
+ */
+void user_return_notifier_unregister(struct user_return_notifier *urn)
+{
+	hlist_del(&urn->link);
+	if (hlist_empty(this_cpu_ptr(&return_notifier_list)))
+		clear_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
+}
+EXPORT_SYMBOL_GPL(user_return_notifier_unregister);
+
+/* Calls registered user return notifiers */
+void fire_user_return_notifiers(void)
+{
+	struct user_return_notifier *urn;
+	struct hlist_node *tmp2;
+	struct hlist_head *head;
+
+	head = &get_cpu_var(return_notifier_list);
+	hlist_for_each_entry_safe(urn, tmp2, head, link)
+		urn->on_user_return(urn);
+	put_cpu_var(return_notifier_list);
+}
diff --git a/kernel/user.c b/kernel/user.c
new file mode 100644
index 000000000..e2cf8c22b
--- /dev/null
+++ b/kernel/user.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * The "user cache".
+ *
+ * (C) Copyright 1991-2000 Linus Torvalds
+ *
+ * We have a per-user structure to keep track of how many
+ * processes, files etc the user has claimed, in order to be
+ * able to have per-user limits for system resources. 
+ */
+
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/bitops.h>
+#include <linux/key.h>
+#include <linux/sched/user.h>
+#include <linux/interrupt.h>
+#include <linux/export.h>
+#include <linux/user_namespace.h>
+#include <linux/proc_ns.h>
+
+/*
+ * userns count is 1 for root user, 1 for init_uts_ns,
+ * and 1 for... ?
+ */
+struct user_namespace init_user_ns = {
+	.uid_map = {
+		.nr_extents = 1,
+		{
+			.extent[0] = {
+				.first = 0,
+				.lower_first = 0,
+				.count = 4294967295U,
+			},
+		},
+	},
+	.gid_map = {
+		.nr_extents = 1,
+		{
+			.extent[0] = {
+				.first = 0,
+				.lower_first = 0,
+				.count = 4294967295U,
+			},
+		},
+	},
+	.projid_map = {
+		.nr_extents = 1,
+		{
+			.extent[0] = {
+				.first = 0,
+				.lower_first = 0,
+				.count = 4294967295U,
+			},
+		},
+	},
+	.ns.count = REFCOUNT_INIT(3),
+	.owner = GLOBAL_ROOT_UID,
+	.group = GLOBAL_ROOT_GID,
+	.ns.inum = PROC_USER_INIT_INO,
+#ifdef CONFIG_USER_NS
+	.ns.ops = &userns_operations,
+#endif
+	.flags = USERNS_INIT_FLAGS,
+#ifdef CONFIG_KEYS
+	.keyring_name_list = LIST_HEAD_INIT(init_user_ns.keyring_name_list),
+	.keyring_sem = __RWSEM_INITIALIZER(init_user_ns.keyring_sem),
+#endif
+};
+EXPORT_SYMBOL_GPL(init_user_ns);
+
+/*
+ * UID task count cache, to get fast user lookup in "alloc_uid"
+ * when changing user ID's (ie setuid() and friends).
+ */
+
+#define UIDHASH_BITS	(CONFIG_BASE_SMALL ? 3 : 7)
+#define UIDHASH_SZ	(1 << UIDHASH_BITS)
+#define UIDHASH_MASK		(UIDHASH_SZ - 1)
+#define __uidhashfn(uid)	(((uid >> UIDHASH_BITS) + uid) & UIDHASH_MASK)
+#define uidhashentry(uid)	(uidhash_table + __uidhashfn((__kuid_val(uid))))
+
+static struct kmem_cache *uid_cachep;
+static struct hlist_head uidhash_table[UIDHASH_SZ];
+
+/*
+ * The uidhash_lock is mostly taken from process context, but it is
+ * occasionally also taken from softirq/tasklet context, when
+ * task-structs get RCU-freed. Hence all locking must be softirq-safe.
+ * But free_uid() is also called with local interrupts disabled, and running
+ * local_bh_enable() with local interrupts disabled is an error - we'll run
+ * softirq callbacks, and they can unconditionally enable interrupts, and
+ * the caller of free_uid() didn't expect that..
+ */
+static DEFINE_SPINLOCK(uidhash_lock);
+
+/* root_user.__count is 1, for init task cred */
+struct user_struct root_user = {
+	.__count	= REFCOUNT_INIT(1),
+	.uid		= GLOBAL_ROOT_UID,
+	.ratelimit	= RATELIMIT_STATE_INIT(root_user.ratelimit, 0, 0),
+};
+
+/*
+ * These routines must be called with the uidhash spinlock held!
+ */
+static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)
+{
+	hlist_add_head(&up->uidhash_node, hashent);
+}
+
+static void uid_hash_remove(struct user_struct *up)
+{
+	hlist_del_init(&up->uidhash_node);
+}
+
+static struct user_struct *uid_hash_find(kuid_t uid, struct hlist_head *hashent)
+{
+	struct user_struct *user;
+
+	hlist_for_each_entry(user, hashent, uidhash_node) {
+		if (uid_eq(user->uid, uid)) {
+			refcount_inc(&user->__count);
+			return user;
+		}
+	}
+
+	return NULL;
+}
+
+static int user_epoll_alloc(struct user_struct *up)
+{
+#ifdef CONFIG_EPOLL
+	return percpu_counter_init(&up->epoll_watches, 0, GFP_KERNEL);
+#else
+	return 0;
+#endif
+}
+
+static void user_epoll_free(struct user_struct *up)
+{
+#ifdef CONFIG_EPOLL
+	percpu_counter_destroy(&up->epoll_watches);
+#endif
+}
+
+/* IRQs are disabled and uidhash_lock is held upon function entry.
+ * IRQ state (as stored in flags) is restored and uidhash_lock released
+ * upon function exit.
+ */
+static void free_user(struct user_struct *up, unsigned long flags)
+	__releases(&uidhash_lock)
+{
+	uid_hash_remove(up);
+	spin_unlock_irqrestore(&uidhash_lock, flags);
+	user_epoll_free(up);
+	kmem_cache_free(uid_cachep, up);
+}
+
+/*
+ * Locate the user_struct for the passed UID.  If found, take a ref on it.  The
+ * caller must undo that ref with free_uid().
+ *
+ * If the user_struct could not be found, return NULL.
+ */
+struct user_struct *find_user(kuid_t uid)
+{
+	struct user_struct *ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&uidhash_lock, flags);
+	ret = uid_hash_find(uid, uidhashentry(uid));
+	spin_unlock_irqrestore(&uidhash_lock, flags);
+	return ret;
+}
+
+void free_uid(struct user_struct *up)
+{
+	unsigned long flags;
+
+	if (!up)
+		return;
+
+	if (refcount_dec_and_lock_irqsave(&up->__count, &uidhash_lock, &flags))
+		free_user(up, flags);
+}
+
+struct user_struct *alloc_uid(kuid_t uid)
+{
+	struct hlist_head *hashent = uidhashentry(uid);
+	struct user_struct *up, *new;
+
+	spin_lock_irq(&uidhash_lock);
+	up = uid_hash_find(uid, hashent);
+	spin_unlock_irq(&uidhash_lock);
+
+	if (!up) {
+		new = kmem_cache_zalloc(uid_cachep, GFP_KERNEL);
+		if (!new)
+			return NULL;
+
+		new->uid = uid;
+		refcount_set(&new->__count, 1);
+		if (user_epoll_alloc(new)) {
+			kmem_cache_free(uid_cachep, new);
+			return NULL;
+		}
+		ratelimit_state_init(&new->ratelimit, HZ, 100);
+		ratelimit_set_flags(&new->ratelimit, RATELIMIT_MSG_ON_RELEASE);
+
+		/*
+		 * Before adding this, check whether we raced
+		 * on adding the same user already..
+		 */
+		spin_lock_irq(&uidhash_lock);
+		up = uid_hash_find(uid, hashent);
+		if (up) {
+			user_epoll_free(new);
+			kmem_cache_free(uid_cachep, new);
+		} else {
+			uid_hash_insert(new, hashent);
+			up = new;
+		}
+		spin_unlock_irq(&uidhash_lock);
+	}
+
+	return up;
+}
+
+static int __init uid_cache_init(void)
+{
+	int n;
+
+	uid_cachep = kmem_cache_create("uid_cache", sizeof(struct user_struct),
+			0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+
+	for(n = 0; n < UIDHASH_SZ; ++n)
+		INIT_HLIST_HEAD(uidhash_table + n);
+
+	if (user_epoll_alloc(&root_user))
+		panic("root_user epoll percpu counter alloc failed");
+
+	/* Insert the root user immediately (init already runs as root) */
+	spin_lock_irq(&uidhash_lock);
+	uid_hash_insert(&root_user, uidhashentry(GLOBAL_ROOT_UID));
+	spin_unlock_irq(&uidhash_lock);
+
+	return 0;
+}
+subsys_initcall(uid_cache_init);
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
new file mode 100644
index 000000000..54211dbd5
--- /dev/null
+++ b/kernel/user_namespace.c
@@ -0,0 +1,1408 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/export.h>
+#include <linux/nsproxy.h>
+#include <linux/slab.h>
+#include <linux/sched/signal.h>
+#include <linux/user_namespace.h>
+#include <linux/proc_ns.h>
+#include <linux/highuid.h>
+#include <linux/cred.h>
+#include <linux/securebits.h>
+#include <linux/security.h>
+#include <linux/keyctl.h>
+#include <linux/key-type.h>
+#include <keys/user-type.h>
+#include <linux/seq_file.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <linux/ctype.h>
+#include <linux/projid.h>
+#include <linux/fs_struct.h>
+#include <linux/bsearch.h>
+#include <linux/sort.h>
+
+static struct kmem_cache *user_ns_cachep __read_mostly;
+static DEFINE_MUTEX(userns_state_mutex);
+
+static bool new_idmap_permitted(const struct file *file,
+				struct user_namespace *ns, int cap_setid,
+				struct uid_gid_map *map);
+static void free_user_ns(struct work_struct *work);
+
+static struct ucounts *inc_user_namespaces(struct user_namespace *ns, kuid_t uid)
+{
+	return inc_ucount(ns, uid, UCOUNT_USER_NAMESPACES);
+}
+
+static void dec_user_namespaces(struct ucounts *ucounts)
+{
+	return dec_ucount(ucounts, UCOUNT_USER_NAMESPACES);
+}
+
+static void set_cred_user_ns(struct cred *cred, struct user_namespace *user_ns)
+{
+	/* Start with the same capabilities as init but useless for doing
+	 * anything as the capabilities are bound to the new user namespace.
+	 */
+	cred->securebits = SECUREBITS_DEFAULT;
+	cred->cap_inheritable = CAP_EMPTY_SET;
+	cred->cap_permitted = CAP_FULL_SET;
+	cred->cap_effective = CAP_FULL_SET;
+	cred->cap_ambient = CAP_EMPTY_SET;
+	cred->cap_bset = CAP_FULL_SET;
+#ifdef CONFIG_KEYS
+	key_put(cred->request_key_auth);
+	cred->request_key_auth = NULL;
+#endif
+	/* tgcred will be cleared in our caller bc CLONE_THREAD won't be set */
+	cred->user_ns = user_ns;
+}
+
+static unsigned long enforced_nproc_rlimit(void)
+{
+	unsigned long limit = RLIM_INFINITY;
+
+	/* Is RLIMIT_NPROC currently enforced? */
+	if (!uid_eq(current_uid(), GLOBAL_ROOT_UID) ||
+	    (current_user_ns() != &init_user_ns))
+		limit = rlimit(RLIMIT_NPROC);
+
+	return limit;
+}
+
+/*
+ * Create a new user namespace, deriving the creator from the user in the
+ * passed credentials, and replacing that user with the new root user for the
+ * new namespace.
+ *
+ * This is called by copy_creds(), which will finish setting the target task's
+ * credentials.
+ */
+int create_user_ns(struct cred *new)
+{
+	struct user_namespace *ns, *parent_ns = new->user_ns;
+	kuid_t owner = new->euid;
+	kgid_t group = new->egid;
+	struct ucounts *ucounts;
+	int ret, i;
+
+	ret = -ENOSPC;
+	if (parent_ns->level > 32)
+		goto fail;
+
+	ucounts = inc_user_namespaces(parent_ns, owner);
+	if (!ucounts)
+		goto fail;
+
+	/*
+	 * Verify that we can not violate the policy of which files
+	 * may be accessed that is specified by the root directory,
+	 * by verifying that the root directory is at the root of the
+	 * mount namespace which allows all files to be accessed.
+	 */
+	ret = -EPERM;
+	if (current_chrooted())
+		goto fail_dec;
+
+	/* The creator needs a mapping in the parent user namespace
+	 * or else we won't be able to reasonably tell userspace who
+	 * created a user_namespace.
+	 */
+	ret = -EPERM;
+	if (!kuid_has_mapping(parent_ns, owner) ||
+	    !kgid_has_mapping(parent_ns, group))
+		goto fail_dec;
+
+	ret = security_create_user_ns(new);
+	if (ret < 0)
+		goto fail_dec;
+
+	ret = -ENOMEM;
+	ns = kmem_cache_zalloc(user_ns_cachep, GFP_KERNEL);
+	if (!ns)
+		goto fail_dec;
+
+	ns->parent_could_setfcap = cap_raised(new->cap_effective, CAP_SETFCAP);
+	ret = ns_alloc_inum(&ns->ns);
+	if (ret)
+		goto fail_free;
+	ns->ns.ops = &userns_operations;
+
+	refcount_set(&ns->ns.count, 1);
+	/* Leave the new->user_ns reference with the new user namespace. */
+	ns->parent = parent_ns;
+	ns->level = parent_ns->level + 1;
+	ns->owner = owner;
+	ns->group = group;
+	INIT_WORK(&ns->work, free_user_ns);
+	for (i = 0; i < UCOUNT_COUNTS; i++) {
+		ns->ucount_max[i] = INT_MAX;
+	}
+	set_userns_rlimit_max(ns, UCOUNT_RLIMIT_NPROC, enforced_nproc_rlimit());
+	set_userns_rlimit_max(ns, UCOUNT_RLIMIT_MSGQUEUE, rlimit(RLIMIT_MSGQUEUE));
+	set_userns_rlimit_max(ns, UCOUNT_RLIMIT_SIGPENDING, rlimit(RLIMIT_SIGPENDING));
+	set_userns_rlimit_max(ns, UCOUNT_RLIMIT_MEMLOCK, rlimit(RLIMIT_MEMLOCK));
+	ns->ucounts = ucounts;
+
+	/* Inherit USERNS_SETGROUPS_ALLOWED from our parent */
+	mutex_lock(&userns_state_mutex);
+	ns->flags = parent_ns->flags;
+	mutex_unlock(&userns_state_mutex);
+
+#ifdef CONFIG_KEYS
+	INIT_LIST_HEAD(&ns->keyring_name_list);
+	init_rwsem(&ns->keyring_sem);
+#endif
+	ret = -ENOMEM;
+	if (!setup_userns_sysctls(ns))
+		goto fail_keyring;
+
+	set_cred_user_ns(new, ns);
+	return 0;
+fail_keyring:
+#ifdef CONFIG_PERSISTENT_KEYRINGS
+	key_put(ns->persistent_keyring_register);
+#endif
+	ns_free_inum(&ns->ns);
+fail_free:
+	kmem_cache_free(user_ns_cachep, ns);
+fail_dec:
+	dec_user_namespaces(ucounts);
+fail:
+	return ret;
+}
+
+int unshare_userns(unsigned long unshare_flags, struct cred **new_cred)
+{
+	struct cred *cred;
+	int err = -ENOMEM;
+
+	if (!(unshare_flags & CLONE_NEWUSER))
+		return 0;
+
+	cred = prepare_creds();
+	if (cred) {
+		err = create_user_ns(cred);
+		if (err)
+			put_cred(cred);
+		else
+			*new_cred = cred;
+	}
+
+	return err;
+}
+
+static void free_user_ns(struct work_struct *work)
+{
+	struct user_namespace *parent, *ns =
+		container_of(work, struct user_namespace, work);
+
+	do {
+		struct ucounts *ucounts = ns->ucounts;
+		parent = ns->parent;
+		if (ns->gid_map.nr_extents > UID_GID_MAP_MAX_BASE_EXTENTS) {
+			kfree(ns->gid_map.forward);
+			kfree(ns->gid_map.reverse);
+		}
+		if (ns->uid_map.nr_extents > UID_GID_MAP_MAX_BASE_EXTENTS) {
+			kfree(ns->uid_map.forward);
+			kfree(ns->uid_map.reverse);
+		}
+		if (ns->projid_map.nr_extents > UID_GID_MAP_MAX_BASE_EXTENTS) {
+			kfree(ns->projid_map.forward);
+			kfree(ns->projid_map.reverse);
+		}
+		retire_userns_sysctls(ns);
+		key_free_user_ns(ns);
+		ns_free_inum(&ns->ns);
+		kmem_cache_free(user_ns_cachep, ns);
+		dec_user_namespaces(ucounts);
+		ns = parent;
+	} while (refcount_dec_and_test(&parent->ns.count));
+}
+
+void __put_user_ns(struct user_namespace *ns)
+{
+	schedule_work(&ns->work);
+}
+EXPORT_SYMBOL(__put_user_ns);
+
+/**
+ * idmap_key struct holds the information necessary to find an idmapping in a
+ * sorted idmap array. It is passed to cmp_map_id() as first argument.
+ */
+struct idmap_key {
+	bool map_up; /* true  -> id from kid; false -> kid from id */
+	u32 id; /* id to find */
+	u32 count; /* == 0 unless used with map_id_range_down() */
+};
+
+/**
+ * cmp_map_id - Function to be passed to bsearch() to find the requested
+ * idmapping. Expects struct idmap_key to be passed via @k.
+ */
+static int cmp_map_id(const void *k, const void *e)
+{
+	u32 first, last, id2;
+	const struct idmap_key *key = k;
+	const struct uid_gid_extent *el = e;
+
+	id2 = key->id + key->count - 1;
+
+	/* handle map_id_{down,up}() */
+	if (key->map_up)
+		first = el->lower_first;
+	else
+		first = el->first;
+
+	last = first + el->count - 1;
+
+	if (key->id >= first && key->id <= last &&
+	    (id2 >= first && id2 <= last))
+		return 0;
+
+	if (key->id < first || id2 < first)
+		return -1;
+
+	return 1;
+}
+
+/**
+ * map_id_range_down_max - Find idmap via binary search in ordered idmap array.
+ * Can only be called if number of mappings exceeds UID_GID_MAP_MAX_BASE_EXTENTS.
+ */
+static struct uid_gid_extent *
+map_id_range_down_max(unsigned extents, struct uid_gid_map *map, u32 id, u32 count)
+{
+	struct idmap_key key;
+
+	key.map_up = false;
+	key.count = count;
+	key.id = id;
+
+	return bsearch(&key, map->forward, extents,
+		       sizeof(struct uid_gid_extent), cmp_map_id);
+}
+
+/**
+ * map_id_range_down_base - Find idmap via binary search in static extent array.
+ * Can only be called if number of mappings is equal or less than
+ * UID_GID_MAP_MAX_BASE_EXTENTS.
+ */
+static struct uid_gid_extent *
+map_id_range_down_base(unsigned extents, struct uid_gid_map *map, u32 id, u32 count)
+{
+	unsigned idx;
+	u32 first, last, id2;
+
+	id2 = id + count - 1;
+
+	/* Find the matching extent */
+	for (idx = 0; idx < extents; idx++) {
+		first = map->extent[idx].first;
+		last = first + map->extent[idx].count - 1;
+		if (id >= first && id <= last &&
+		    (id2 >= first && id2 <= last))
+			return &map->extent[idx];
+	}
+	return NULL;
+}
+
+static u32 map_id_range_down(struct uid_gid_map *map, u32 id, u32 count)
+{
+	struct uid_gid_extent *extent;
+	unsigned extents = map->nr_extents;
+	smp_rmb();
+
+	if (extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+		extent = map_id_range_down_base(extents, map, id, count);
+	else
+		extent = map_id_range_down_max(extents, map, id, count);
+
+	/* Map the id or note failure */
+	if (extent)
+		id = (id - extent->first) + extent->lower_first;
+	else
+		id = (u32) -1;
+
+	return id;
+}
+
+static u32 map_id_down(struct uid_gid_map *map, u32 id)
+{
+	return map_id_range_down(map, id, 1);
+}
+
+/**
+ * map_id_up_base - Find idmap via binary search in static extent array.
+ * Can only be called if number of mappings is equal or less than
+ * UID_GID_MAP_MAX_BASE_EXTENTS.
+ */
+static struct uid_gid_extent *
+map_id_up_base(unsigned extents, struct uid_gid_map *map, u32 id)
+{
+	unsigned idx;
+	u32 first, last;
+
+	/* Find the matching extent */
+	for (idx = 0; idx < extents; idx++) {
+		first = map->extent[idx].lower_first;
+		last = first + map->extent[idx].count - 1;
+		if (id >= first && id <= last)
+			return &map->extent[idx];
+	}
+	return NULL;
+}
+
+/**
+ * map_id_up_max - Find idmap via binary search in ordered idmap array.
+ * Can only be called if number of mappings exceeds UID_GID_MAP_MAX_BASE_EXTENTS.
+ */
+static struct uid_gid_extent *
+map_id_up_max(unsigned extents, struct uid_gid_map *map, u32 id)
+{
+	struct idmap_key key;
+
+	key.map_up = true;
+	key.count = 1;
+	key.id = id;
+
+	return bsearch(&key, map->reverse, extents,
+		       sizeof(struct uid_gid_extent), cmp_map_id);
+}
+
+static u32 map_id_up(struct uid_gid_map *map, u32 id)
+{
+	struct uid_gid_extent *extent;
+	unsigned extents = map->nr_extents;
+	smp_rmb();
+
+	if (extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+		extent = map_id_up_base(extents, map, id);
+	else
+		extent = map_id_up_max(extents, map, id);
+
+	/* Map the id or note failure */
+	if (extent)
+		id = (id - extent->lower_first) + extent->first;
+	else
+		id = (u32) -1;
+
+	return id;
+}
+
+/**
+ *	make_kuid - Map a user-namespace uid pair into a kuid.
+ *	@ns:  User namespace that the uid is in
+ *	@uid: User identifier
+ *
+ *	Maps a user-namespace uid pair into a kernel internal kuid,
+ *	and returns that kuid.
+ *
+ *	When there is no mapping defined for the user-namespace uid
+ *	pair INVALID_UID is returned.  Callers are expected to test
+ *	for and handle INVALID_UID being returned.  INVALID_UID
+ *	may be tested for using uid_valid().
+ */
+kuid_t make_kuid(struct user_namespace *ns, uid_t uid)
+{
+	/* Map the uid to a global kernel uid */
+	return KUIDT_INIT(map_id_down(&ns->uid_map, uid));
+}
+EXPORT_SYMBOL(make_kuid);
+
+/**
+ *	from_kuid - Create a uid from a kuid user-namespace pair.
+ *	@targ: The user namespace we want a uid in.
+ *	@kuid: The kernel internal uid to start with.
+ *
+ *	Map @kuid into the user-namespace specified by @targ and
+ *	return the resulting uid.
+ *
+ *	There is always a mapping into the initial user_namespace.
+ *
+ *	If @kuid has no mapping in @targ (uid_t)-1 is returned.
+ */
+uid_t from_kuid(struct user_namespace *targ, kuid_t kuid)
+{
+	/* Map the uid from a global kernel uid */
+	return map_id_up(&targ->uid_map, __kuid_val(kuid));
+}
+EXPORT_SYMBOL(from_kuid);
+
+/**
+ *	from_kuid_munged - Create a uid from a kuid user-namespace pair.
+ *	@targ: The user namespace we want a uid in.
+ *	@kuid: The kernel internal uid to start with.
+ *
+ *	Map @kuid into the user-namespace specified by @targ and
+ *	return the resulting uid.
+ *
+ *	There is always a mapping into the initial user_namespace.
+ *
+ *	Unlike from_kuid from_kuid_munged never fails and always
+ *	returns a valid uid.  This makes from_kuid_munged appropriate
+ *	for use in syscalls like stat and getuid where failing the
+ *	system call and failing to provide a valid uid are not an
+ *	options.
+ *
+ *	If @kuid has no mapping in @targ overflowuid is returned.
+ */
+uid_t from_kuid_munged(struct user_namespace *targ, kuid_t kuid)
+{
+	uid_t uid;
+	uid = from_kuid(targ, kuid);
+
+	if (uid == (uid_t) -1)
+		uid = overflowuid;
+	return uid;
+}
+EXPORT_SYMBOL(from_kuid_munged);
+
+/**
+ *	make_kgid - Map a user-namespace gid pair into a kgid.
+ *	@ns:  User namespace that the gid is in
+ *	@gid: group identifier
+ *
+ *	Maps a user-namespace gid pair into a kernel internal kgid,
+ *	and returns that kgid.
+ *
+ *	When there is no mapping defined for the user-namespace gid
+ *	pair INVALID_GID is returned.  Callers are expected to test
+ *	for and handle INVALID_GID being returned.  INVALID_GID may be
+ *	tested for using gid_valid().
+ */
+kgid_t make_kgid(struct user_namespace *ns, gid_t gid)
+{
+	/* Map the gid to a global kernel gid */
+	return KGIDT_INIT(map_id_down(&ns->gid_map, gid));
+}
+EXPORT_SYMBOL(make_kgid);
+
+/**
+ *	from_kgid - Create a gid from a kgid user-namespace pair.
+ *	@targ: The user namespace we want a gid in.
+ *	@kgid: The kernel internal gid to start with.
+ *
+ *	Map @kgid into the user-namespace specified by @targ and
+ *	return the resulting gid.
+ *
+ *	There is always a mapping into the initial user_namespace.
+ *
+ *	If @kgid has no mapping in @targ (gid_t)-1 is returned.
+ */
+gid_t from_kgid(struct user_namespace *targ, kgid_t kgid)
+{
+	/* Map the gid from a global kernel gid */
+	return map_id_up(&targ->gid_map, __kgid_val(kgid));
+}
+EXPORT_SYMBOL(from_kgid);
+
+/**
+ *	from_kgid_munged - Create a gid from a kgid user-namespace pair.
+ *	@targ: The user namespace we want a gid in.
+ *	@kgid: The kernel internal gid to start with.
+ *
+ *	Map @kgid into the user-namespace specified by @targ and
+ *	return the resulting gid.
+ *
+ *	There is always a mapping into the initial user_namespace.
+ *
+ *	Unlike from_kgid from_kgid_munged never fails and always
+ *	returns a valid gid.  This makes from_kgid_munged appropriate
+ *	for use in syscalls like stat and getgid where failing the
+ *	system call and failing to provide a valid gid are not options.
+ *
+ *	If @kgid has no mapping in @targ overflowgid is returned.
+ */
+gid_t from_kgid_munged(struct user_namespace *targ, kgid_t kgid)
+{
+	gid_t gid;
+	gid = from_kgid(targ, kgid);
+
+	if (gid == (gid_t) -1)
+		gid = overflowgid;
+	return gid;
+}
+EXPORT_SYMBOL(from_kgid_munged);
+
+/**
+ *	make_kprojid - Map a user-namespace projid pair into a kprojid.
+ *	@ns:  User namespace that the projid is in
+ *	@projid: Project identifier
+ *
+ *	Maps a user-namespace uid pair into a kernel internal kuid,
+ *	and returns that kuid.
+ *
+ *	When there is no mapping defined for the user-namespace projid
+ *	pair INVALID_PROJID is returned.  Callers are expected to test
+ *	for and handle INVALID_PROJID being returned.  INVALID_PROJID
+ *	may be tested for using projid_valid().
+ */
+kprojid_t make_kprojid(struct user_namespace *ns, projid_t projid)
+{
+	/* Map the uid to a global kernel uid */
+	return KPROJIDT_INIT(map_id_down(&ns->projid_map, projid));
+}
+EXPORT_SYMBOL(make_kprojid);
+
+/**
+ *	from_kprojid - Create a projid from a kprojid user-namespace pair.
+ *	@targ: The user namespace we want a projid in.
+ *	@kprojid: The kernel internal project identifier to start with.
+ *
+ *	Map @kprojid into the user-namespace specified by @targ and
+ *	return the resulting projid.
+ *
+ *	There is always a mapping into the initial user_namespace.
+ *
+ *	If @kprojid has no mapping in @targ (projid_t)-1 is returned.
+ */
+projid_t from_kprojid(struct user_namespace *targ, kprojid_t kprojid)
+{
+	/* Map the uid from a global kernel uid */
+	return map_id_up(&targ->projid_map, __kprojid_val(kprojid));
+}
+EXPORT_SYMBOL(from_kprojid);
+
+/**
+ *	from_kprojid_munged - Create a projiid from a kprojid user-namespace pair.
+ *	@targ: The user namespace we want a projid in.
+ *	@kprojid: The kernel internal projid to start with.
+ *
+ *	Map @kprojid into the user-namespace specified by @targ and
+ *	return the resulting projid.
+ *
+ *	There is always a mapping into the initial user_namespace.
+ *
+ *	Unlike from_kprojid from_kprojid_munged never fails and always
+ *	returns a valid projid.  This makes from_kprojid_munged
+ *	appropriate for use in syscalls like stat and where
+ *	failing the system call and failing to provide a valid projid are
+ *	not an options.
+ *
+ *	If @kprojid has no mapping in @targ OVERFLOW_PROJID is returned.
+ */
+projid_t from_kprojid_munged(struct user_namespace *targ, kprojid_t kprojid)
+{
+	projid_t projid;
+	projid = from_kprojid(targ, kprojid);
+
+	if (projid == (projid_t) -1)
+		projid = OVERFLOW_PROJID;
+	return projid;
+}
+EXPORT_SYMBOL(from_kprojid_munged);
+
+
+static int uid_m_show(struct seq_file *seq, void *v)
+{
+	struct user_namespace *ns = seq->private;
+	struct uid_gid_extent *extent = v;
+	struct user_namespace *lower_ns;
+	uid_t lower;
+
+	lower_ns = seq_user_ns(seq);
+	if ((lower_ns == ns) && lower_ns->parent)
+		lower_ns = lower_ns->parent;
+
+	lower = from_kuid(lower_ns, KUIDT_INIT(extent->lower_first));
+
+	seq_printf(seq, "%10u %10u %10u\n",
+		extent->first,
+		lower,
+		extent->count);
+
+	return 0;
+}
+
+static int gid_m_show(struct seq_file *seq, void *v)
+{
+	struct user_namespace *ns = seq->private;
+	struct uid_gid_extent *extent = v;
+	struct user_namespace *lower_ns;
+	gid_t lower;
+
+	lower_ns = seq_user_ns(seq);
+	if ((lower_ns == ns) && lower_ns->parent)
+		lower_ns = lower_ns->parent;
+
+	lower = from_kgid(lower_ns, KGIDT_INIT(extent->lower_first));
+
+	seq_printf(seq, "%10u %10u %10u\n",
+		extent->first,
+		lower,
+		extent->count);
+
+	return 0;
+}
+
+static int projid_m_show(struct seq_file *seq, void *v)
+{
+	struct user_namespace *ns = seq->private;
+	struct uid_gid_extent *extent = v;
+	struct user_namespace *lower_ns;
+	projid_t lower;
+
+	lower_ns = seq_user_ns(seq);
+	if ((lower_ns == ns) && lower_ns->parent)
+		lower_ns = lower_ns->parent;
+
+	lower = from_kprojid(lower_ns, KPROJIDT_INIT(extent->lower_first));
+
+	seq_printf(seq, "%10u %10u %10u\n",
+		extent->first,
+		lower,
+		extent->count);
+
+	return 0;
+}
+
+static void *m_start(struct seq_file *seq, loff_t *ppos,
+		     struct uid_gid_map *map)
+{
+	loff_t pos = *ppos;
+	unsigned extents = map->nr_extents;
+	smp_rmb();
+
+	if (pos >= extents)
+		return NULL;
+
+	if (extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+		return &map->extent[pos];
+
+	return &map->forward[pos];
+}
+
+static void *uid_m_start(struct seq_file *seq, loff_t *ppos)
+{
+	struct user_namespace *ns = seq->private;
+
+	return m_start(seq, ppos, &ns->uid_map);
+}
+
+static void *gid_m_start(struct seq_file *seq, loff_t *ppos)
+{
+	struct user_namespace *ns = seq->private;
+
+	return m_start(seq, ppos, &ns->gid_map);
+}
+
+static void *projid_m_start(struct seq_file *seq, loff_t *ppos)
+{
+	struct user_namespace *ns = seq->private;
+
+	return m_start(seq, ppos, &ns->projid_map);
+}
+
+static void *m_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	(*pos)++;
+	return seq->op->start(seq, pos);
+}
+
+static void m_stop(struct seq_file *seq, void *v)
+{
+	return;
+}
+
+const struct seq_operations proc_uid_seq_operations = {
+	.start = uid_m_start,
+	.stop = m_stop,
+	.next = m_next,
+	.show = uid_m_show,
+};
+
+const struct seq_operations proc_gid_seq_operations = {
+	.start = gid_m_start,
+	.stop = m_stop,
+	.next = m_next,
+	.show = gid_m_show,
+};
+
+const struct seq_operations proc_projid_seq_operations = {
+	.start = projid_m_start,
+	.stop = m_stop,
+	.next = m_next,
+	.show = projid_m_show,
+};
+
+static bool mappings_overlap(struct uid_gid_map *new_map,
+			     struct uid_gid_extent *extent)
+{
+	u32 upper_first, lower_first, upper_last, lower_last;
+	unsigned idx;
+
+	upper_first = extent->first;
+	lower_first = extent->lower_first;
+	upper_last = upper_first + extent->count - 1;
+	lower_last = lower_first + extent->count - 1;
+
+	for (idx = 0; idx < new_map->nr_extents; idx++) {
+		u32 prev_upper_first, prev_lower_first;
+		u32 prev_upper_last, prev_lower_last;
+		struct uid_gid_extent *prev;
+
+		if (new_map->nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+			prev = &new_map->extent[idx];
+		else
+			prev = &new_map->forward[idx];
+
+		prev_upper_first = prev->first;
+		prev_lower_first = prev->lower_first;
+		prev_upper_last = prev_upper_first + prev->count - 1;
+		prev_lower_last = prev_lower_first + prev->count - 1;
+
+		/* Does the upper range intersect a previous extent? */
+		if ((prev_upper_first <= upper_last) &&
+		    (prev_upper_last >= upper_first))
+			return true;
+
+		/* Does the lower range intersect a previous extent? */
+		if ((prev_lower_first <= lower_last) &&
+		    (prev_lower_last >= lower_first))
+			return true;
+	}
+	return false;
+}
+
+/**
+ * insert_extent - Safely insert a new idmap extent into struct uid_gid_map.
+ * Takes care to allocate a 4K block of memory if the number of mappings exceeds
+ * UID_GID_MAP_MAX_BASE_EXTENTS.
+ */
+static int insert_extent(struct uid_gid_map *map, struct uid_gid_extent *extent)
+{
+	struct uid_gid_extent *dest;
+
+	if (map->nr_extents == UID_GID_MAP_MAX_BASE_EXTENTS) {
+		struct uid_gid_extent *forward;
+
+		/* Allocate memory for 340 mappings. */
+		forward = kmalloc_array(UID_GID_MAP_MAX_EXTENTS,
+					sizeof(struct uid_gid_extent),
+					GFP_KERNEL);
+		if (!forward)
+			return -ENOMEM;
+
+		/* Copy over memory. Only set up memory for the forward pointer.
+		 * Defer the memory setup for the reverse pointer.
+		 */
+		memcpy(forward, map->extent,
+		       map->nr_extents * sizeof(map->extent[0]));
+
+		map->forward = forward;
+		map->reverse = NULL;
+	}
+
+	if (map->nr_extents < UID_GID_MAP_MAX_BASE_EXTENTS)
+		dest = &map->extent[map->nr_extents];
+	else
+		dest = &map->forward[map->nr_extents];
+
+	*dest = *extent;
+	map->nr_extents++;
+	return 0;
+}
+
+/* cmp function to sort() forward mappings */
+static int cmp_extents_forward(const void *a, const void *b)
+{
+	const struct uid_gid_extent *e1 = a;
+	const struct uid_gid_extent *e2 = b;
+
+	if (e1->first < e2->first)
+		return -1;
+
+	if (e1->first > e2->first)
+		return 1;
+
+	return 0;
+}
+
+/* cmp function to sort() reverse mappings */
+static int cmp_extents_reverse(const void *a, const void *b)
+{
+	const struct uid_gid_extent *e1 = a;
+	const struct uid_gid_extent *e2 = b;
+
+	if (e1->lower_first < e2->lower_first)
+		return -1;
+
+	if (e1->lower_first > e2->lower_first)
+		return 1;
+
+	return 0;
+}
+
+/**
+ * sort_idmaps - Sorts an array of idmap entries.
+ * Can only be called if number of mappings exceeds UID_GID_MAP_MAX_BASE_EXTENTS.
+ */
+static int sort_idmaps(struct uid_gid_map *map)
+{
+	if (map->nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+		return 0;
+
+	/* Sort forward array. */
+	sort(map->forward, map->nr_extents, sizeof(struct uid_gid_extent),
+	     cmp_extents_forward, NULL);
+
+	/* Only copy the memory from forward we actually need. */
+	map->reverse = kmemdup(map->forward,
+			       map->nr_extents * sizeof(struct uid_gid_extent),
+			       GFP_KERNEL);
+	if (!map->reverse)
+		return -ENOMEM;
+
+	/* Sort reverse array. */
+	sort(map->reverse, map->nr_extents, sizeof(struct uid_gid_extent),
+	     cmp_extents_reverse, NULL);
+
+	return 0;
+}
+
+/**
+ * verify_root_map() - check the uid 0 mapping
+ * @file: idmapping file
+ * @map_ns: user namespace of the target process
+ * @new_map: requested idmap
+ *
+ * If a process requests mapping parent uid 0 into the new ns, verify that the
+ * process writing the map had the CAP_SETFCAP capability as the target process
+ * will be able to write fscaps that are valid in ancestor user namespaces.
+ *
+ * Return: true if the mapping is allowed, false if not.
+ */
+static bool verify_root_map(const struct file *file,
+			    struct user_namespace *map_ns,
+			    struct uid_gid_map *new_map)
+{
+	int idx;
+	const struct user_namespace *file_ns = file->f_cred->user_ns;
+	struct uid_gid_extent *extent0 = NULL;
+
+	for (idx = 0; idx < new_map->nr_extents; idx++) {
+		if (new_map->nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+			extent0 = &new_map->extent[idx];
+		else
+			extent0 = &new_map->forward[idx];
+		if (extent0->lower_first == 0)
+			break;
+
+		extent0 = NULL;
+	}
+
+	if (!extent0)
+		return true;
+
+	if (map_ns == file_ns) {
+		/* The process unshared its ns and is writing to its own
+		 * /proc/self/uid_map.  User already has full capabilites in
+		 * the new namespace.  Verify that the parent had CAP_SETFCAP
+		 * when it unshared.
+		 * */
+		if (!file_ns->parent_could_setfcap)
+			return false;
+	} else {
+		/* Process p1 is writing to uid_map of p2, who is in a child
+		 * user namespace to p1's.  Verify that the opener of the map
+		 * file has CAP_SETFCAP against the parent of the new map
+		 * namespace */
+		if (!file_ns_capable(file, map_ns->parent, CAP_SETFCAP))
+			return false;
+	}
+
+	return true;
+}
+
+static ssize_t map_write(struct file *file, const char __user *buf,
+			 size_t count, loff_t *ppos,
+			 int cap_setid,
+			 struct uid_gid_map *map,
+			 struct uid_gid_map *parent_map)
+{
+	struct seq_file *seq = file->private_data;
+	struct user_namespace *map_ns = seq->private;
+	struct uid_gid_map new_map;
+	unsigned idx;
+	struct uid_gid_extent extent;
+	char *kbuf = NULL, *pos, *next_line;
+	ssize_t ret;
+
+	/* Only allow < page size writes at the beginning of the file */
+	if ((*ppos != 0) || (count >= PAGE_SIZE))
+		return -EINVAL;
+
+	/* Slurp in the user data */
+	kbuf = memdup_user_nul(buf, count);
+	if (IS_ERR(kbuf))
+		return PTR_ERR(kbuf);
+
+	/*
+	 * The userns_state_mutex serializes all writes to any given map.
+	 *
+	 * Any map is only ever written once.
+	 *
+	 * An id map fits within 1 cache line on most architectures.
+	 *
+	 * On read nothing needs to be done unless you are on an
+	 * architecture with a crazy cache coherency model like alpha.
+	 *
+	 * There is a one time data dependency between reading the
+	 * count of the extents and the values of the extents.  The
+	 * desired behavior is to see the values of the extents that
+	 * were written before the count of the extents.
+	 *
+	 * To achieve this smp_wmb() is used on guarantee the write
+	 * order and smp_rmb() is guaranteed that we don't have crazy
+	 * architectures returning stale data.
+	 */
+	mutex_lock(&userns_state_mutex);
+
+	memset(&new_map, 0, sizeof(struct uid_gid_map));
+
+	ret = -EPERM;
+	/* Only allow one successful write to the map */
+	if (map->nr_extents != 0)
+		goto out;
+
+	/*
+	 * Adjusting namespace settings requires capabilities on the target.
+	 */
+	if (cap_valid(cap_setid) && !file_ns_capable(file, map_ns, CAP_SYS_ADMIN))
+		goto out;
+
+	/* Parse the user data */
+	ret = -EINVAL;
+	pos = kbuf;
+	for (; pos; pos = next_line) {
+
+		/* Find the end of line and ensure I don't look past it */
+		next_line = strchr(pos, '\n');
+		if (next_line) {
+			*next_line = '\0';
+			next_line++;
+			if (*next_line == '\0')
+				next_line = NULL;
+		}
+
+		pos = skip_spaces(pos);
+		extent.first = simple_strtoul(pos, &pos, 10);
+		if (!isspace(*pos))
+			goto out;
+
+		pos = skip_spaces(pos);
+		extent.lower_first = simple_strtoul(pos, &pos, 10);
+		if (!isspace(*pos))
+			goto out;
+
+		pos = skip_spaces(pos);
+		extent.count = simple_strtoul(pos, &pos, 10);
+		if (*pos && !isspace(*pos))
+			goto out;
+
+		/* Verify there is not trailing junk on the line */
+		pos = skip_spaces(pos);
+		if (*pos != '\0')
+			goto out;
+
+		/* Verify we have been given valid starting values */
+		if ((extent.first == (u32) -1) ||
+		    (extent.lower_first == (u32) -1))
+			goto out;
+
+		/* Verify count is not zero and does not cause the
+		 * extent to wrap
+		 */
+		if ((extent.first + extent.count) <= extent.first)
+			goto out;
+		if ((extent.lower_first + extent.count) <=
+		     extent.lower_first)
+			goto out;
+
+		/* Do the ranges in extent overlap any previous extents? */
+		if (mappings_overlap(&new_map, &extent))
+			goto out;
+
+		if ((new_map.nr_extents + 1) == UID_GID_MAP_MAX_EXTENTS &&
+		    (next_line != NULL))
+			goto out;
+
+		ret = insert_extent(&new_map, &extent);
+		if (ret < 0)
+			goto out;
+		ret = -EINVAL;
+	}
+	/* Be very certain the new map actually exists */
+	if (new_map.nr_extents == 0)
+		goto out;
+
+	ret = -EPERM;
+	/* Validate the user is allowed to use user id's mapped to. */
+	if (!new_idmap_permitted(file, map_ns, cap_setid, &new_map))
+		goto out;
+
+	ret = -EPERM;
+	/* Map the lower ids from the parent user namespace to the
+	 * kernel global id space.
+	 */
+	for (idx = 0; idx < new_map.nr_extents; idx++) {
+		struct uid_gid_extent *e;
+		u32 lower_first;
+
+		if (new_map.nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
+			e = &new_map.extent[idx];
+		else
+			e = &new_map.forward[idx];
+
+		lower_first = map_id_range_down(parent_map,
+						e->lower_first,
+						e->count);
+
+		/* Fail if we can not map the specified extent to
+		 * the kernel global id space.
+		 */
+		if (lower_first == (u32) -1)
+			goto out;
+
+		e->lower_first = lower_first;
+	}
+
+	/*
+	 * If we want to use binary search for lookup, this clones the extent
+	 * array and sorts both copies.
+	 */
+	ret = sort_idmaps(&new_map);
+	if (ret < 0)
+		goto out;
+
+	/* Install the map */
+	if (new_map.nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS) {
+		memcpy(map->extent, new_map.extent,
+		       new_map.nr_extents * sizeof(new_map.extent[0]));
+	} else {
+		map->forward = new_map.forward;
+		map->reverse = new_map.reverse;
+	}
+	smp_wmb();
+	map->nr_extents = new_map.nr_extents;
+
+	*ppos = count;
+	ret = count;
+out:
+	if (ret < 0 && new_map.nr_extents > UID_GID_MAP_MAX_BASE_EXTENTS) {
+		kfree(new_map.forward);
+		kfree(new_map.reverse);
+		map->forward = NULL;
+		map->reverse = NULL;
+		map->nr_extents = 0;
+	}
+
+	mutex_unlock(&userns_state_mutex);
+	kfree(kbuf);
+	return ret;
+}
+
+ssize_t proc_uid_map_write(struct file *file, const char __user *buf,
+			   size_t size, loff_t *ppos)
+{
+	struct seq_file *seq = file->private_data;
+	struct user_namespace *ns = seq->private;
+	struct user_namespace *seq_ns = seq_user_ns(seq);
+
+	if (!ns->parent)
+		return -EPERM;
+
+	if ((seq_ns != ns) && (seq_ns != ns->parent))
+		return -EPERM;
+
+	return map_write(file, buf, size, ppos, CAP_SETUID,
+			 &ns->uid_map, &ns->parent->uid_map);
+}
+
+ssize_t proc_gid_map_write(struct file *file, const char __user *buf,
+			   size_t size, loff_t *ppos)
+{
+	struct seq_file *seq = file->private_data;
+	struct user_namespace *ns = seq->private;
+	struct user_namespace *seq_ns = seq_user_ns(seq);
+
+	if (!ns->parent)
+		return -EPERM;
+
+	if ((seq_ns != ns) && (seq_ns != ns->parent))
+		return -EPERM;
+
+	return map_write(file, buf, size, ppos, CAP_SETGID,
+			 &ns->gid_map, &ns->parent->gid_map);
+}
+
+ssize_t proc_projid_map_write(struct file *file, const char __user *buf,
+			      size_t size, loff_t *ppos)
+{
+	struct seq_file *seq = file->private_data;
+	struct user_namespace *ns = seq->private;
+	struct user_namespace *seq_ns = seq_user_ns(seq);
+
+	if (!ns->parent)
+		return -EPERM;
+
+	if ((seq_ns != ns) && (seq_ns != ns->parent))
+		return -EPERM;
+
+	/* Anyone can set any valid project id no capability needed */
+	return map_write(file, buf, size, ppos, -1,
+			 &ns->projid_map, &ns->parent->projid_map);
+}
+
+static bool new_idmap_permitted(const struct file *file,
+				struct user_namespace *ns, int cap_setid,
+				struct uid_gid_map *new_map)
+{
+	const struct cred *cred = file->f_cred;
+
+	if (cap_setid == CAP_SETUID && !verify_root_map(file, ns, new_map))
+		return false;
+
+	/* Don't allow mappings that would allow anything that wouldn't
+	 * be allowed without the establishment of unprivileged mappings.
+	 */
+	if ((new_map->nr_extents == 1) && (new_map->extent[0].count == 1) &&
+	    uid_eq(ns->owner, cred->euid)) {
+		u32 id = new_map->extent[0].lower_first;
+		if (cap_setid == CAP_SETUID) {
+			kuid_t uid = make_kuid(ns->parent, id);
+			if (uid_eq(uid, cred->euid))
+				return true;
+		} else if (cap_setid == CAP_SETGID) {
+			kgid_t gid = make_kgid(ns->parent, id);
+			if (!(ns->flags & USERNS_SETGROUPS_ALLOWED) &&
+			    gid_eq(gid, cred->egid))
+				return true;
+		}
+	}
+
+	/* Allow anyone to set a mapping that doesn't require privilege */
+	if (!cap_valid(cap_setid))
+		return true;
+
+	/* Allow the specified ids if we have the appropriate capability
+	 * (CAP_SETUID or CAP_SETGID) over the parent user namespace.
+	 * And the opener of the id file also has the appropriate capability.
+	 */
+	if (ns_capable(ns->parent, cap_setid) &&
+	    file_ns_capable(file, ns->parent, cap_setid))
+		return true;
+
+	return false;
+}
+
+int proc_setgroups_show(struct seq_file *seq, void *v)
+{
+	struct user_namespace *ns = seq->private;
+	unsigned long userns_flags = READ_ONCE(ns->flags);
+
+	seq_printf(seq, "%s\n",
+		   (userns_flags & USERNS_SETGROUPS_ALLOWED) ?
+		   "allow" : "deny");
+	return 0;
+}
+
+ssize_t proc_setgroups_write(struct file *file, const char __user *buf,
+			     size_t count, loff_t *ppos)
+{
+	struct seq_file *seq = file->private_data;
+	struct user_namespace *ns = seq->private;
+	char kbuf[8], *pos;
+	bool setgroups_allowed;
+	ssize_t ret;
+
+	/* Only allow a very narrow range of strings to be written */
+	ret = -EINVAL;
+	if ((*ppos != 0) || (count >= sizeof(kbuf)))
+		goto out;
+
+	/* What was written? */
+	ret = -EFAULT;
+	if (copy_from_user(kbuf, buf, count))
+		goto out;
+	kbuf[count] = '\0';
+	pos = kbuf;
+
+	/* What is being requested? */
+	ret = -EINVAL;
+	if (strncmp(pos, "allow", 5) == 0) {
+		pos += 5;
+		setgroups_allowed = true;
+	}
+	else if (strncmp(pos, "deny", 4) == 0) {
+		pos += 4;
+		setgroups_allowed = false;
+	}
+	else
+		goto out;
+
+	/* Verify there is not trailing junk on the line */
+	pos = skip_spaces(pos);
+	if (*pos != '\0')
+		goto out;
+
+	ret = -EPERM;
+	mutex_lock(&userns_state_mutex);
+	if (setgroups_allowed) {
+		/* Enabling setgroups after setgroups has been disabled
+		 * is not allowed.
+		 */
+		if (!(ns->flags & USERNS_SETGROUPS_ALLOWED))
+			goto out_unlock;
+	} else {
+		/* Permanently disabling setgroups after setgroups has
+		 * been enabled by writing the gid_map is not allowed.
+		 */
+		if (ns->gid_map.nr_extents != 0)
+			goto out_unlock;
+		ns->flags &= ~USERNS_SETGROUPS_ALLOWED;
+	}
+	mutex_unlock(&userns_state_mutex);
+
+	/* Report a successful write */
+	*ppos = count;
+	ret = count;
+out:
+	return ret;
+out_unlock:
+	mutex_unlock(&userns_state_mutex);
+	goto out;
+}
+
+bool userns_may_setgroups(const struct user_namespace *ns)
+{
+	bool allowed;
+
+	mutex_lock(&userns_state_mutex);
+	/* It is not safe to use setgroups until a gid mapping in
+	 * the user namespace has been established.
+	 */
+	allowed = ns->gid_map.nr_extents != 0;
+	/* Is setgroups allowed? */
+	allowed = allowed && (ns->flags & USERNS_SETGROUPS_ALLOWED);
+	mutex_unlock(&userns_state_mutex);
+
+	return allowed;
+}
+
+/*
+ * Returns true if @child is the same namespace or a descendant of
+ * @ancestor.
+ */
+bool in_userns(const struct user_namespace *ancestor,
+	       const struct user_namespace *child)
+{
+	const struct user_namespace *ns;
+	for (ns = child; ns->level > ancestor->level; ns = ns->parent)
+		;
+	return (ns == ancestor);
+}
+
+bool current_in_userns(const struct user_namespace *target_ns)
+{
+	return in_userns(target_ns, current_user_ns());
+}
+EXPORT_SYMBOL(current_in_userns);
+
+static inline struct user_namespace *to_user_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct user_namespace, ns);
+}
+
+static struct ns_common *userns_get(struct task_struct *task)
+{
+	struct user_namespace *user_ns;
+
+	rcu_read_lock();
+	user_ns = get_user_ns(__task_cred(task)->user_ns);
+	rcu_read_unlock();
+
+	return user_ns ? &user_ns->ns : NULL;
+}
+
+static void userns_put(struct ns_common *ns)
+{
+	put_user_ns(to_user_ns(ns));
+}
+
+static int userns_install(struct nsset *nsset, struct ns_common *ns)
+{
+	struct user_namespace *user_ns = to_user_ns(ns);
+	struct cred *cred;
+
+	/* Don't allow gaining capabilities by reentering
+	 * the same user namespace.
+	 */
+	if (user_ns == current_user_ns())
+		return -EINVAL;
+
+	/* Tasks that share a thread group must share a user namespace */
+	if (!thread_group_empty(current))
+		return -EINVAL;
+
+	if (current->fs->users != 1)
+		return -EINVAL;
+
+	if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	cred = nsset_cred(nsset);
+	if (!cred)
+		return -EINVAL;
+
+	put_user_ns(cred->user_ns);
+	set_cred_user_ns(cred, get_user_ns(user_ns));
+
+	if (set_cred_ucounts(cred) < 0)
+		return -EINVAL;
+
+	return 0;
+}
+
+struct ns_common *ns_get_owner(struct ns_common *ns)
+{
+	struct user_namespace *my_user_ns = current_user_ns();
+	struct user_namespace *owner, *p;
+
+	/* See if the owner is in the current user namespace */
+	owner = p = ns->ops->owner(ns);
+	for (;;) {
+		if (!p)
+			return ERR_PTR(-EPERM);
+		if (p == my_user_ns)
+			break;
+		p = p->parent;
+	}
+
+	return &get_user_ns(owner)->ns;
+}
+
+static struct user_namespace *userns_owner(struct ns_common *ns)
+{
+	return to_user_ns(ns)->parent;
+}
+
+const struct proc_ns_operations userns_operations = {
+	.name		= "user",
+	.type		= CLONE_NEWUSER,
+	.get		= userns_get,
+	.put		= userns_put,
+	.install	= userns_install,
+	.owner		= userns_owner,
+	.get_parent	= ns_get_owner,
+};
+
+static __init int user_namespaces_init(void)
+{
+	user_ns_cachep = KMEM_CACHE(user_namespace, SLAB_PANIC | SLAB_ACCOUNT);
+	return 0;
+}
+subsys_initcall(user_namespaces_init);
diff --git a/kernel/usermode_driver.c b/kernel/usermode_driver.c
new file mode 100644
index 000000000..8303f4c7c
--- /dev/null
+++ b/kernel/usermode_driver.c
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * umd - User mode driver support
+ */
+#include <linux/shmem_fs.h>
+#include <linux/pipe_fs_i.h>
+#include <linux/mount.h>
+#include <linux/fs_struct.h>
+#include <linux/task_work.h>
+#include <linux/usermode_driver.h>
+
+static struct vfsmount *blob_to_mnt(const void *data, size_t len, const char *name)
+{
+	struct file_system_type *type;
+	struct vfsmount *mnt;
+	struct file *file;
+	ssize_t written;
+	loff_t pos = 0;
+
+	type = get_fs_type("tmpfs");
+	if (!type)
+		return ERR_PTR(-ENODEV);
+
+	mnt = kern_mount(type);
+	put_filesystem(type);
+	if (IS_ERR(mnt))
+		return mnt;
+
+	file = file_open_root_mnt(mnt, name, O_CREAT | O_WRONLY, 0700);
+	if (IS_ERR(file)) {
+		kern_unmount(mnt);
+		return ERR_CAST(file);
+	}
+
+	written = kernel_write(file, data, len, &pos);
+	if (written != len) {
+		int err = written;
+		if (err >= 0)
+			err = -ENOMEM;
+		filp_close(file, NULL);
+		kern_unmount(mnt);
+		return ERR_PTR(err);
+	}
+
+	fput(file);
+
+	/* Flush delayed fput so exec can open the file read-only */
+	flush_delayed_fput();
+	task_work_run();
+	return mnt;
+}
+
+/**
+ * umd_load_blob - Remember a blob of bytes for fork_usermode_driver
+ * @info: information about usermode driver
+ * @data: a blob of bytes that can be executed as a file
+ * @len:  The lentgh of the blob
+ *
+ */
+int umd_load_blob(struct umd_info *info, const void *data, size_t len)
+{
+	struct vfsmount *mnt;
+
+	if (WARN_ON_ONCE(info->wd.dentry || info->wd.mnt))
+		return -EBUSY;
+
+	mnt = blob_to_mnt(data, len, info->driver_name);
+	if (IS_ERR(mnt))
+		return PTR_ERR(mnt);
+
+	info->wd.mnt = mnt;
+	info->wd.dentry = mnt->mnt_root;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(umd_load_blob);
+
+/**
+ * umd_unload_blob - Disassociate @info from a previously loaded blob
+ * @info: information about usermode driver
+ *
+ */
+int umd_unload_blob(struct umd_info *info)
+{
+	if (WARN_ON_ONCE(!info->wd.mnt ||
+			 !info->wd.dentry ||
+			 info->wd.mnt->mnt_root != info->wd.dentry))
+		return -EINVAL;
+
+	kern_unmount(info->wd.mnt);
+	info->wd.mnt = NULL;
+	info->wd.dentry = NULL;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(umd_unload_blob);
+
+static int umd_setup(struct subprocess_info *info, struct cred *new)
+{
+	struct umd_info *umd_info = info->data;
+	struct file *from_umh[2];
+	struct file *to_umh[2];
+	int err;
+
+	/* create pipe to send data to umh */
+	err = create_pipe_files(to_umh, 0);
+	if (err)
+		return err;
+	err = replace_fd(0, to_umh[0], 0);
+	fput(to_umh[0]);
+	if (err < 0) {
+		fput(to_umh[1]);
+		return err;
+	}
+
+	/* create pipe to receive data from umh */
+	err = create_pipe_files(from_umh, 0);
+	if (err) {
+		fput(to_umh[1]);
+		replace_fd(0, NULL, 0);
+		return err;
+	}
+	err = replace_fd(1, from_umh[1], 0);
+	fput(from_umh[1]);
+	if (err < 0) {
+		fput(to_umh[1]);
+		replace_fd(0, NULL, 0);
+		fput(from_umh[0]);
+		return err;
+	}
+
+	set_fs_pwd(current->fs, &umd_info->wd);
+	umd_info->pipe_to_umh = to_umh[1];
+	umd_info->pipe_from_umh = from_umh[0];
+	umd_info->tgid = get_pid(task_tgid(current));
+	return 0;
+}
+
+static void umd_cleanup(struct subprocess_info *info)
+{
+	struct umd_info *umd_info = info->data;
+
+	/* cleanup if umh_setup() was successful but exec failed */
+	if (info->retval)
+		umd_cleanup_helper(umd_info);
+}
+
+/**
+ * umd_cleanup_helper - release the resources which were allocated in umd_setup
+ * @info: information about usermode driver
+ */
+void umd_cleanup_helper(struct umd_info *info)
+{
+	fput(info->pipe_to_umh);
+	fput(info->pipe_from_umh);
+	put_pid(info->tgid);
+	info->tgid = NULL;
+}
+EXPORT_SYMBOL_GPL(umd_cleanup_helper);
+
+/**
+ * fork_usermode_driver - fork a usermode driver
+ * @info: information about usermode driver (shouldn't be NULL)
+ *
+ * Returns either negative error or zero which indicates success in
+ * executing a usermode driver. In such case 'struct umd_info *info'
+ * is populated with two pipes and a tgid of the process. The caller is
+ * responsible for health check of the user process, killing it via
+ * tgid, and closing the pipes when user process is no longer needed.
+ */
+int fork_usermode_driver(struct umd_info *info)
+{
+	struct subprocess_info *sub_info;
+	const char *argv[] = { info->driver_name, NULL };
+	int err;
+
+	if (WARN_ON_ONCE(info->tgid))
+		return -EBUSY;
+
+	err = -ENOMEM;
+	sub_info = call_usermodehelper_setup(info->driver_name,
+					     (char **)argv, NULL, GFP_KERNEL,
+					     umd_setup, umd_cleanup, info);
+	if (!sub_info)
+		goto out;
+
+	err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
+out:
+	return err;
+}
+EXPORT_SYMBOL_GPL(fork_usermode_driver);
+
+
diff --git a/kernel/utsname.c b/kernel/utsname.c
new file mode 100644
index 000000000..b1ac3ca87
--- /dev/null
+++ b/kernel/utsname.c
@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Copyright (C) 2004 IBM Corporation
+ *
+ *  Author: Serge Hallyn <serue@us.ibm.com>
+ */
+
+#include <linux/export.h>
+#include <linux/uts.h>
+#include <linux/utsname.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/cred.h>
+#include <linux/user_namespace.h>
+#include <linux/proc_ns.h>
+#include <linux/sched/task.h>
+
+static struct kmem_cache *uts_ns_cache __ro_after_init;
+
+static struct ucounts *inc_uts_namespaces(struct user_namespace *ns)
+{
+	return inc_ucount(ns, current_euid(), UCOUNT_UTS_NAMESPACES);
+}
+
+static void dec_uts_namespaces(struct ucounts *ucounts)
+{
+	dec_ucount(ucounts, UCOUNT_UTS_NAMESPACES);
+}
+
+static struct uts_namespace *create_uts_ns(void)
+{
+	struct uts_namespace *uts_ns;
+
+	uts_ns = kmem_cache_alloc(uts_ns_cache, GFP_KERNEL);
+	if (uts_ns)
+		refcount_set(&uts_ns->ns.count, 1);
+	return uts_ns;
+}
+
+/*
+ * Clone a new ns copying an original utsname, setting refcount to 1
+ * @old_ns: namespace to clone
+ * Return ERR_PTR(-ENOMEM) on error (failure to allocate), new ns otherwise
+ */
+static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns,
+					  struct uts_namespace *old_ns)
+{
+	struct uts_namespace *ns;
+	struct ucounts *ucounts;
+	int err;
+
+	err = -ENOSPC;
+	ucounts = inc_uts_namespaces(user_ns);
+	if (!ucounts)
+		goto fail;
+
+	err = -ENOMEM;
+	ns = create_uts_ns();
+	if (!ns)
+		goto fail_dec;
+
+	err = ns_alloc_inum(&ns->ns);
+	if (err)
+		goto fail_free;
+
+	ns->ucounts = ucounts;
+	ns->ns.ops = &utsns_operations;
+
+	down_read(&uts_sem);
+	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
+	ns->user_ns = get_user_ns(user_ns);
+	up_read(&uts_sem);
+	return ns;
+
+fail_free:
+	kmem_cache_free(uts_ns_cache, ns);
+fail_dec:
+	dec_uts_namespaces(ucounts);
+fail:
+	return ERR_PTR(err);
+}
+
+/*
+ * Copy task tsk's utsname namespace, or clone it if flags
+ * specifies CLONE_NEWUTS.  In latter case, changes to the
+ * utsname of this process won't be seen by parent, and vice
+ * versa.
+ */
+struct uts_namespace *copy_utsname(unsigned long flags,
+	struct user_namespace *user_ns, struct uts_namespace *old_ns)
+{
+	struct uts_namespace *new_ns;
+
+	BUG_ON(!old_ns);
+	get_uts_ns(old_ns);
+
+	if (!(flags & CLONE_NEWUTS))
+		return old_ns;
+
+	new_ns = clone_uts_ns(user_ns, old_ns);
+
+	put_uts_ns(old_ns);
+	return new_ns;
+}
+
+void free_uts_ns(struct uts_namespace *ns)
+{
+	dec_uts_namespaces(ns->ucounts);
+	put_user_ns(ns->user_ns);
+	ns_free_inum(&ns->ns);
+	kmem_cache_free(uts_ns_cache, ns);
+}
+
+static inline struct uts_namespace *to_uts_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct uts_namespace, ns);
+}
+
+static struct ns_common *utsns_get(struct task_struct *task)
+{
+	struct uts_namespace *ns = NULL;
+	struct nsproxy *nsproxy;
+
+	task_lock(task);
+	nsproxy = task->nsproxy;
+	if (nsproxy) {
+		ns = nsproxy->uts_ns;
+		get_uts_ns(ns);
+	}
+	task_unlock(task);
+
+	return ns ? &ns->ns : NULL;
+}
+
+static void utsns_put(struct ns_common *ns)
+{
+	put_uts_ns(to_uts_ns(ns));
+}
+
+static int utsns_install(struct nsset *nsset, struct ns_common *new)
+{
+	struct nsproxy *nsproxy = nsset->nsproxy;
+	struct uts_namespace *ns = to_uts_ns(new);
+
+	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
+	    !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	get_uts_ns(ns);
+	put_uts_ns(nsproxy->uts_ns);
+	nsproxy->uts_ns = ns;
+	return 0;
+}
+
+static struct user_namespace *utsns_owner(struct ns_common *ns)
+{
+	return to_uts_ns(ns)->user_ns;
+}
+
+const struct proc_ns_operations utsns_operations = {
+	.name		= "uts",
+	.type		= CLONE_NEWUTS,
+	.get		= utsns_get,
+	.put		= utsns_put,
+	.install	= utsns_install,
+	.owner		= utsns_owner,
+};
+
+void __init uts_ns_init(void)
+{
+	uts_ns_cache = kmem_cache_create_usercopy(
+			"uts_namespace", sizeof(struct uts_namespace), 0,
+			SLAB_PANIC|SLAB_ACCOUNT,
+			offsetof(struct uts_namespace, name),
+			sizeof_field(struct uts_namespace, name),
+			NULL);
+}
diff --git a/kernel/utsname_sysctl.c b/kernel/utsname_sysctl.c
new file mode 100644
index 000000000..f50398cb7
--- /dev/null
+++ b/kernel/utsname_sysctl.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Copyright (C) 2007
+ *
+ *  Author: Eric Biederman <ebiederm@xmision.com>
+ */
+
+#include <linux/export.h>
+#include <linux/uts.h>
+#include <linux/utsname.h>
+#include <linux/random.h>
+#include <linux/sysctl.h>
+#include <linux/wait.h>
+#include <linux/rwsem.h>
+
+#ifdef CONFIG_PROC_SYSCTL
+
+static void *get_uts(struct ctl_table *table)
+{
+	char *which = table->data;
+	struct uts_namespace *uts_ns;
+
+	uts_ns = current->nsproxy->uts_ns;
+	which = (which - (char *)&init_uts_ns) + (char *)uts_ns;
+
+	return which;
+}
+
+/*
+ *	Special case of dostring for the UTS structure. This has locks
+ *	to observe. Should this be in kernel/sys.c ????
+ */
+static int proc_do_uts_string(struct ctl_table *table, int write,
+		  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table uts_table;
+	int r;
+	char tmp_data[__NEW_UTS_LEN + 1];
+
+	memcpy(&uts_table, table, sizeof(uts_table));
+	uts_table.data = tmp_data;
+
+	/*
+	 * Buffer the value in tmp_data so that proc_dostring() can be called
+	 * without holding any locks.
+	 * We also need to read the original value in the write==1 case to
+	 * support partial writes.
+	 */
+	down_read(&uts_sem);
+	memcpy(tmp_data, get_uts(table), sizeof(tmp_data));
+	up_read(&uts_sem);
+	r = proc_dostring(&uts_table, write, buffer, lenp, ppos);
+
+	if (write) {
+		/*
+		 * Write back the new value.
+		 * Note that, since we dropped uts_sem, the result can
+		 * theoretically be incorrect if there are two parallel writes
+		 * at non-zero offsets to the same sysctl.
+		 */
+		add_device_randomness(tmp_data, sizeof(tmp_data));
+		down_write(&uts_sem);
+		memcpy(get_uts(table), tmp_data, sizeof(tmp_data));
+		up_write(&uts_sem);
+		proc_sys_poll_notify(table->poll);
+	}
+
+	return r;
+}
+#else
+#define proc_do_uts_string NULL
+#endif
+
+static DEFINE_CTL_TABLE_POLL(hostname_poll);
+static DEFINE_CTL_TABLE_POLL(domainname_poll);
+
+// Note: update 'enum uts_proc' to match any changes to this table
+static struct ctl_table uts_kern_table[] = {
+	{
+		.procname	= "arch",
+		.data		= init_uts_ns.name.machine,
+		.maxlen		= sizeof(init_uts_ns.name.machine),
+		.mode		= 0444,
+		.proc_handler	= proc_do_uts_string,
+	},
+	{
+		.procname	= "ostype",
+		.data		= init_uts_ns.name.sysname,
+		.maxlen		= sizeof(init_uts_ns.name.sysname),
+		.mode		= 0444,
+		.proc_handler	= proc_do_uts_string,
+	},
+	{
+		.procname	= "osrelease",
+		.data		= init_uts_ns.name.release,
+		.maxlen		= sizeof(init_uts_ns.name.release),
+		.mode		= 0444,
+		.proc_handler	= proc_do_uts_string,
+	},
+	{
+		.procname	= "version",
+		.data		= init_uts_ns.name.version,
+		.maxlen		= sizeof(init_uts_ns.name.version),
+		.mode		= 0444,
+		.proc_handler	= proc_do_uts_string,
+	},
+	{
+		.procname	= "hostname",
+		.data		= init_uts_ns.name.nodename,
+		.maxlen		= sizeof(init_uts_ns.name.nodename),
+		.mode		= 0644,
+		.proc_handler	= proc_do_uts_string,
+		.poll		= &hostname_poll,
+	},
+	{
+		.procname	= "domainname",
+		.data		= init_uts_ns.name.domainname,
+		.maxlen		= sizeof(init_uts_ns.name.domainname),
+		.mode		= 0644,
+		.proc_handler	= proc_do_uts_string,
+		.poll		= &domainname_poll,
+	},
+	{}
+};
+
+static struct ctl_table uts_root_table[] = {
+	{
+		.procname	= "kernel",
+		.mode		= 0555,
+		.child		= uts_kern_table,
+	},
+	{}
+};
+
+#ifdef CONFIG_PROC_SYSCTL
+/*
+ * Notify userspace about a change in a certain entry of uts_kern_table,
+ * identified by the parameter proc.
+ */
+void uts_proc_notify(enum uts_proc proc)
+{
+	struct ctl_table *table = &uts_kern_table[proc];
+
+	proc_sys_poll_notify(table->poll);
+}
+#endif
+
+static int __init utsname_sysctl_init(void)
+{
+	register_sysctl_table(uts_root_table);
+	return 0;
+}
+
+device_initcall(utsname_sysctl_init);
diff --git a/kernel/watch_queue.c b/kernel/watch_queue.c
new file mode 100644
index 000000000..442bb9221
--- /dev/null
+++ b/kernel/watch_queue.c
@@ -0,0 +1,701 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Watch queue and general notification mechanism, built on pipes
+ *
+ * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * See Documentation/core-api/watch_queue.rst
+ */
+
+#define pr_fmt(fmt) "watchq: " fmt
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/printk.h>
+#include <linux/miscdevice.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/poll.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <linux/file.h>
+#include <linux/security.h>
+#include <linux/cred.h>
+#include <linux/sched/signal.h>
+#include <linux/watch_queue.h>
+#include <linux/pipe_fs_i.h>
+
+MODULE_DESCRIPTION("Watch queue");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL");
+
+#define WATCH_QUEUE_NOTE_SIZE 128
+#define WATCH_QUEUE_NOTES_PER_PAGE (PAGE_SIZE / WATCH_QUEUE_NOTE_SIZE)
+
+/*
+ * This must be called under the RCU read-lock, which makes
+ * sure that the wqueue still exists. It can then take the lock,
+ * and check that the wqueue hasn't been destroyed, which in
+ * turn makes sure that the notification pipe still exists.
+ */
+static inline bool lock_wqueue(struct watch_queue *wqueue)
+{
+	spin_lock_bh(&wqueue->lock);
+	if (unlikely(!wqueue->pipe)) {
+		spin_unlock_bh(&wqueue->lock);
+		return false;
+	}
+	return true;
+}
+
+static inline void unlock_wqueue(struct watch_queue *wqueue)
+{
+	spin_unlock_bh(&wqueue->lock);
+}
+
+static void watch_queue_pipe_buf_release(struct pipe_inode_info *pipe,
+					 struct pipe_buffer *buf)
+{
+	struct watch_queue *wqueue = (struct watch_queue *)buf->private;
+	struct page *page;
+	unsigned int bit;
+
+	/* We need to work out which note within the page this refers to, but
+	 * the note might have been maximum size, so merely ANDing the offset
+	 * off doesn't work.  OTOH, the note must've been more than zero size.
+	 */
+	bit = buf->offset + buf->len;
+	if ((bit & (WATCH_QUEUE_NOTE_SIZE - 1)) == 0)
+		bit -= WATCH_QUEUE_NOTE_SIZE;
+	bit /= WATCH_QUEUE_NOTE_SIZE;
+
+	page = buf->page;
+	bit += page->index;
+
+	set_bit(bit, wqueue->notes_bitmap);
+	generic_pipe_buf_release(pipe, buf);
+}
+
+// No try_steal function => no stealing
+#define watch_queue_pipe_buf_try_steal NULL
+
+/* New data written to a pipe may be appended to a buffer with this type. */
+static const struct pipe_buf_operations watch_queue_pipe_buf_ops = {
+	.release	= watch_queue_pipe_buf_release,
+	.try_steal	= watch_queue_pipe_buf_try_steal,
+	.get		= generic_pipe_buf_get,
+};
+
+/*
+ * Post a notification to a watch queue.
+ *
+ * Must be called with the RCU lock for reading, and the
+ * watch_queue lock held, which guarantees that the pipe
+ * hasn't been released.
+ */
+static bool post_one_notification(struct watch_queue *wqueue,
+				  struct watch_notification *n)
+{
+	void *p;
+	struct pipe_inode_info *pipe = wqueue->pipe;
+	struct pipe_buffer *buf;
+	struct page *page;
+	unsigned int head, tail, mask, note, offset, len;
+	bool done = false;
+
+	spin_lock_irq(&pipe->rd_wait.lock);
+
+	mask = pipe->ring_size - 1;
+	head = pipe->head;
+	tail = pipe->tail;
+	if (pipe_full(head, tail, pipe->ring_size))
+		goto lost;
+
+	note = find_first_bit(wqueue->notes_bitmap, wqueue->nr_notes);
+	if (note >= wqueue->nr_notes)
+		goto lost;
+
+	page = wqueue->notes[note / WATCH_QUEUE_NOTES_PER_PAGE];
+	offset = note % WATCH_QUEUE_NOTES_PER_PAGE * WATCH_QUEUE_NOTE_SIZE;
+	get_page(page);
+	len = n->info & WATCH_INFO_LENGTH;
+	p = kmap_atomic(page);
+	memcpy(p + offset, n, len);
+	kunmap_atomic(p);
+
+	buf = &pipe->bufs[head & mask];
+	buf->page = page;
+	buf->private = (unsigned long)wqueue;
+	buf->ops = &watch_queue_pipe_buf_ops;
+	buf->offset = offset;
+	buf->len = len;
+	buf->flags = PIPE_BUF_FLAG_WHOLE;
+	smp_store_release(&pipe->head, head + 1); /* vs pipe_read() */
+
+	if (!test_and_clear_bit(note, wqueue->notes_bitmap)) {
+		spin_unlock_irq(&pipe->rd_wait.lock);
+		BUG();
+	}
+	wake_up_interruptible_sync_poll_locked(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM);
+	done = true;
+
+out:
+	spin_unlock_irq(&pipe->rd_wait.lock);
+	if (done)
+		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
+	return done;
+
+lost:
+	buf = &pipe->bufs[(head - 1) & mask];
+	buf->flags |= PIPE_BUF_FLAG_LOSS;
+	goto out;
+}
+
+/*
+ * Apply filter rules to a notification.
+ */
+static bool filter_watch_notification(const struct watch_filter *wf,
+				      const struct watch_notification *n)
+{
+	const struct watch_type_filter *wt;
+	unsigned int st_bits = sizeof(wt->subtype_filter[0]) * 8;
+	unsigned int st_index = n->subtype / st_bits;
+	unsigned int st_bit = 1U << (n->subtype % st_bits);
+	int i;
+
+	if (!test_bit(n->type, wf->type_filter))
+		return false;
+
+	for (i = 0; i < wf->nr_filters; i++) {
+		wt = &wf->filters[i];
+		if (n->type == wt->type &&
+		    (wt->subtype_filter[st_index] & st_bit) &&
+		    (n->info & wt->info_mask) == wt->info_filter)
+			return true;
+	}
+
+	return false; /* If there is a filter, the default is to reject. */
+}
+
+/**
+ * __post_watch_notification - Post an event notification
+ * @wlist: The watch list to post the event to.
+ * @n: The notification record to post.
+ * @cred: The creds of the process that triggered the notification.
+ * @id: The ID to match on the watch.
+ *
+ * Post a notification of an event into a set of watch queues and let the users
+ * know.
+ *
+ * The size of the notification should be set in n->info & WATCH_INFO_LENGTH and
+ * should be in units of sizeof(*n).
+ */
+void __post_watch_notification(struct watch_list *wlist,
+			       struct watch_notification *n,
+			       const struct cred *cred,
+			       u64 id)
+{
+	const struct watch_filter *wf;
+	struct watch_queue *wqueue;
+	struct watch *watch;
+
+	if (((n->info & WATCH_INFO_LENGTH) >> WATCH_INFO_LENGTH__SHIFT) == 0) {
+		WARN_ON(1);
+		return;
+	}
+
+	rcu_read_lock();
+
+	hlist_for_each_entry_rcu(watch, &wlist->watchers, list_node) {
+		if (watch->id != id)
+			continue;
+		n->info &= ~WATCH_INFO_ID;
+		n->info |= watch->info_id;
+
+		wqueue = rcu_dereference(watch->queue);
+		wf = rcu_dereference(wqueue->filter);
+		if (wf && !filter_watch_notification(wf, n))
+			continue;
+
+		if (security_post_notification(watch->cred, cred, n) < 0)
+			continue;
+
+		if (lock_wqueue(wqueue)) {
+			post_one_notification(wqueue, n);
+			unlock_wqueue(wqueue);
+		}
+	}
+
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(__post_watch_notification);
+
+/*
+ * Allocate sufficient pages to preallocation for the requested number of
+ * notifications.
+ */
+long watch_queue_set_size(struct pipe_inode_info *pipe, unsigned int nr_notes)
+{
+	struct watch_queue *wqueue = pipe->watch_queue;
+	struct page **pages;
+	unsigned long *bitmap;
+	unsigned long user_bufs;
+	int ret, i, nr_pages;
+
+	if (!wqueue)
+		return -ENODEV;
+	if (wqueue->notes)
+		return -EBUSY;
+
+	if (nr_notes < 1 ||
+	    nr_notes > 512) /* TODO: choose a better hard limit */
+		return -EINVAL;
+
+	nr_pages = (nr_notes + WATCH_QUEUE_NOTES_PER_PAGE - 1);
+	nr_pages /= WATCH_QUEUE_NOTES_PER_PAGE;
+	user_bufs = account_pipe_buffers(pipe->user, pipe->nr_accounted, nr_pages);
+
+	if (nr_pages > pipe->max_usage &&
+	    (too_many_pipe_buffers_hard(user_bufs) ||
+	     too_many_pipe_buffers_soft(user_bufs)) &&
+	    pipe_is_unprivileged_user()) {
+		ret = -EPERM;
+		goto error;
+	}
+
+	nr_notes = nr_pages * WATCH_QUEUE_NOTES_PER_PAGE;
+	ret = pipe_resize_ring(pipe, roundup_pow_of_two(nr_notes));
+	if (ret < 0)
+		goto error;
+
+	ret = -ENOMEM;
+	pages = kcalloc(sizeof(struct page *), nr_pages, GFP_KERNEL);
+	if (!pages)
+		goto error;
+
+	for (i = 0; i < nr_pages; i++) {
+		pages[i] = alloc_page(GFP_KERNEL);
+		if (!pages[i])
+			goto error_p;
+		pages[i]->index = i * WATCH_QUEUE_NOTES_PER_PAGE;
+	}
+
+	bitmap = bitmap_alloc(nr_notes, GFP_KERNEL);
+	if (!bitmap)
+		goto error_p;
+
+	bitmap_fill(bitmap, nr_notes);
+	wqueue->notes = pages;
+	wqueue->notes_bitmap = bitmap;
+	wqueue->nr_pages = nr_pages;
+	wqueue->nr_notes = nr_notes;
+	return 0;
+
+error_p:
+	while (--i >= 0)
+		__free_page(pages[i]);
+	kfree(pages);
+error:
+	(void) account_pipe_buffers(pipe->user, nr_pages, pipe->nr_accounted);
+	return ret;
+}
+
+/*
+ * Set the filter on a watch queue.
+ */
+long watch_queue_set_filter(struct pipe_inode_info *pipe,
+			    struct watch_notification_filter __user *_filter)
+{
+	struct watch_notification_type_filter *tf;
+	struct watch_notification_filter filter;
+	struct watch_type_filter *q;
+	struct watch_filter *wfilter;
+	struct watch_queue *wqueue = pipe->watch_queue;
+	int ret, nr_filter = 0, i;
+
+	if (!wqueue)
+		return -ENODEV;
+
+	if (!_filter) {
+		/* Remove the old filter */
+		wfilter = NULL;
+		goto set;
+	}
+
+	/* Grab the user's filter specification */
+	if (copy_from_user(&filter, _filter, sizeof(filter)) != 0)
+		return -EFAULT;
+	if (filter.nr_filters == 0 ||
+	    filter.nr_filters > 16 ||
+	    filter.__reserved != 0)
+		return -EINVAL;
+
+	tf = memdup_array_user(_filter->filters, filter.nr_filters, sizeof(*tf));
+	if (IS_ERR(tf))
+		return PTR_ERR(tf);
+
+	ret = -EINVAL;
+	for (i = 0; i < filter.nr_filters; i++) {
+		if ((tf[i].info_filter & ~tf[i].info_mask) ||
+		    tf[i].info_mask & WATCH_INFO_LENGTH)
+			goto err_filter;
+		/* Ignore any unknown types */
+		if (tf[i].type >= WATCH_TYPE__NR)
+			continue;
+		nr_filter++;
+	}
+
+	/* Now we need to build the internal filter from only the relevant
+	 * user-specified filters.
+	 */
+	ret = -ENOMEM;
+	wfilter = kzalloc(struct_size(wfilter, filters, nr_filter), GFP_KERNEL);
+	if (!wfilter)
+		goto err_filter;
+	wfilter->nr_filters = nr_filter;
+
+	q = wfilter->filters;
+	for (i = 0; i < filter.nr_filters; i++) {
+		if (tf[i].type >= WATCH_TYPE__NR)
+			continue;
+
+		q->type			= tf[i].type;
+		q->info_filter		= tf[i].info_filter;
+		q->info_mask		= tf[i].info_mask;
+		q->subtype_filter[0]	= tf[i].subtype_filter[0];
+		__set_bit(q->type, wfilter->type_filter);
+		q++;
+	}
+
+	kfree(tf);
+set:
+	pipe_lock(pipe);
+	wfilter = rcu_replace_pointer(wqueue->filter, wfilter,
+				      lockdep_is_held(&pipe->mutex));
+	pipe_unlock(pipe);
+	if (wfilter)
+		kfree_rcu(wfilter, rcu);
+	return 0;
+
+err_filter:
+	kfree(tf);
+	return ret;
+}
+
+static void __put_watch_queue(struct kref *kref)
+{
+	struct watch_queue *wqueue =
+		container_of(kref, struct watch_queue, usage);
+	struct watch_filter *wfilter;
+	int i;
+
+	for (i = 0; i < wqueue->nr_pages; i++)
+		__free_page(wqueue->notes[i]);
+	kfree(wqueue->notes);
+	bitmap_free(wqueue->notes_bitmap);
+
+	wfilter = rcu_access_pointer(wqueue->filter);
+	if (wfilter)
+		kfree_rcu(wfilter, rcu);
+	kfree_rcu(wqueue, rcu);
+}
+
+/**
+ * put_watch_queue - Dispose of a ref on a watchqueue.
+ * @wqueue: The watch queue to unref.
+ */
+void put_watch_queue(struct watch_queue *wqueue)
+{
+	kref_put(&wqueue->usage, __put_watch_queue);
+}
+EXPORT_SYMBOL(put_watch_queue);
+
+static void free_watch(struct rcu_head *rcu)
+{
+	struct watch *watch = container_of(rcu, struct watch, rcu);
+
+	put_watch_queue(rcu_access_pointer(watch->queue));
+	atomic_dec(&watch->cred->user->nr_watches);
+	put_cred(watch->cred);
+	kfree(watch);
+}
+
+static void __put_watch(struct kref *kref)
+{
+	struct watch *watch = container_of(kref, struct watch, usage);
+
+	call_rcu(&watch->rcu, free_watch);
+}
+
+/*
+ * Discard a watch.
+ */
+static void put_watch(struct watch *watch)
+{
+	kref_put(&watch->usage, __put_watch);
+}
+
+/**
+ * init_watch - Initialise a watch
+ * @watch: The watch to initialise.
+ * @wqueue: The queue to assign.
+ *
+ * Initialise a watch and set the watch queue.
+ */
+void init_watch(struct watch *watch, struct watch_queue *wqueue)
+{
+	kref_init(&watch->usage);
+	INIT_HLIST_NODE(&watch->list_node);
+	INIT_HLIST_NODE(&watch->queue_node);
+	rcu_assign_pointer(watch->queue, wqueue);
+}
+
+static int add_one_watch(struct watch *watch, struct watch_list *wlist, struct watch_queue *wqueue)
+{
+	const struct cred *cred;
+	struct watch *w;
+
+	hlist_for_each_entry(w, &wlist->watchers, list_node) {
+		struct watch_queue *wq = rcu_access_pointer(w->queue);
+		if (wqueue == wq && watch->id == w->id)
+			return -EBUSY;
+	}
+
+	cred = current_cred();
+	if (atomic_inc_return(&cred->user->nr_watches) > task_rlimit(current, RLIMIT_NOFILE)) {
+		atomic_dec(&cred->user->nr_watches);
+		return -EAGAIN;
+	}
+
+	watch->cred = get_cred(cred);
+	rcu_assign_pointer(watch->watch_list, wlist);
+
+	kref_get(&wqueue->usage);
+	kref_get(&watch->usage);
+	hlist_add_head(&watch->queue_node, &wqueue->watches);
+	hlist_add_head_rcu(&watch->list_node, &wlist->watchers);
+	return 0;
+}
+
+/**
+ * add_watch_to_object - Add a watch on an object to a watch list
+ * @watch: The watch to add
+ * @wlist: The watch list to add to
+ *
+ * @watch->queue must have been set to point to the queue to post notifications
+ * to and the watch list of the object to be watched.  @watch->cred must also
+ * have been set to the appropriate credentials and a ref taken on them.
+ *
+ * The caller must pin the queue and the list both and must hold the list
+ * locked against racing watch additions/removals.
+ */
+int add_watch_to_object(struct watch *watch, struct watch_list *wlist)
+{
+	struct watch_queue *wqueue;
+	int ret = -ENOENT;
+
+	rcu_read_lock();
+
+	wqueue = rcu_access_pointer(watch->queue);
+	if (lock_wqueue(wqueue)) {
+		spin_lock(&wlist->lock);
+		ret = add_one_watch(watch, wlist, wqueue);
+		spin_unlock(&wlist->lock);
+		unlock_wqueue(wqueue);
+	}
+
+	rcu_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL(add_watch_to_object);
+
+/**
+ * remove_watch_from_object - Remove a watch or all watches from an object.
+ * @wlist: The watch list to remove from
+ * @wq: The watch queue of interest (ignored if @all is true)
+ * @id: The ID of the watch to remove (ignored if @all is true)
+ * @all: True to remove all objects
+ *
+ * Remove a specific watch or all watches from an object.  A notification is
+ * sent to the watcher to tell them that this happened.
+ */
+int remove_watch_from_object(struct watch_list *wlist, struct watch_queue *wq,
+			     u64 id, bool all)
+{
+	struct watch_notification_removal n;
+	struct watch_queue *wqueue;
+	struct watch *watch;
+	int ret = -EBADSLT;
+
+	rcu_read_lock();
+
+again:
+	spin_lock(&wlist->lock);
+	hlist_for_each_entry(watch, &wlist->watchers, list_node) {
+		if (all ||
+		    (watch->id == id && rcu_access_pointer(watch->queue) == wq))
+			goto found;
+	}
+	spin_unlock(&wlist->lock);
+	goto out;
+
+found:
+	ret = 0;
+	hlist_del_init_rcu(&watch->list_node);
+	rcu_assign_pointer(watch->watch_list, NULL);
+	spin_unlock(&wlist->lock);
+
+	/* We now own the reference on watch that used to belong to wlist. */
+
+	n.watch.type = WATCH_TYPE_META;
+	n.watch.subtype = WATCH_META_REMOVAL_NOTIFICATION;
+	n.watch.info = watch->info_id | watch_sizeof(n.watch);
+	n.id = id;
+	if (id != 0)
+		n.watch.info = watch->info_id | watch_sizeof(n);
+
+	wqueue = rcu_dereference(watch->queue);
+
+	if (lock_wqueue(wqueue)) {
+		post_one_notification(wqueue, &n.watch);
+
+		if (!hlist_unhashed(&watch->queue_node)) {
+			hlist_del_init_rcu(&watch->queue_node);
+			put_watch(watch);
+		}
+
+		unlock_wqueue(wqueue);
+	}
+
+	if (wlist->release_watch) {
+		void (*release_watch)(struct watch *);
+
+		release_watch = wlist->release_watch;
+		rcu_read_unlock();
+		(*release_watch)(watch);
+		rcu_read_lock();
+	}
+	put_watch(watch);
+
+	if (all && !hlist_empty(&wlist->watchers))
+		goto again;
+out:
+	rcu_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL(remove_watch_from_object);
+
+/*
+ * Remove all the watches that are contributory to a queue.  This has the
+ * potential to race with removal of the watches by the destruction of the
+ * objects being watched or with the distribution of notifications.
+ */
+void watch_queue_clear(struct watch_queue *wqueue)
+{
+	struct watch_list *wlist;
+	struct watch *watch;
+	bool release;
+
+	rcu_read_lock();
+	spin_lock_bh(&wqueue->lock);
+
+	/*
+	 * This pipe can be freed by callers like free_pipe_info().
+	 * Removing this reference also prevents new notifications.
+	 */
+	wqueue->pipe = NULL;
+
+	while (!hlist_empty(&wqueue->watches)) {
+		watch = hlist_entry(wqueue->watches.first, struct watch, queue_node);
+		hlist_del_init_rcu(&watch->queue_node);
+		/* We now own a ref on the watch. */
+		spin_unlock_bh(&wqueue->lock);
+
+		/* We can't do the next bit under the queue lock as we need to
+		 * get the list lock - which would cause a deadlock if someone
+		 * was removing from the opposite direction at the same time or
+		 * posting a notification.
+		 */
+		wlist = rcu_dereference(watch->watch_list);
+		if (wlist) {
+			void (*release_watch)(struct watch *);
+
+			spin_lock(&wlist->lock);
+
+			release = !hlist_unhashed(&watch->list_node);
+			if (release) {
+				hlist_del_init_rcu(&watch->list_node);
+				rcu_assign_pointer(watch->watch_list, NULL);
+
+				/* We now own a second ref on the watch. */
+			}
+
+			release_watch = wlist->release_watch;
+			spin_unlock(&wlist->lock);
+
+			if (release) {
+				if (release_watch) {
+					rcu_read_unlock();
+					/* This might need to call dput(), so
+					 * we have to drop all the locks.
+					 */
+					(*release_watch)(watch);
+					rcu_read_lock();
+				}
+				put_watch(watch);
+			}
+		}
+
+		put_watch(watch);
+		spin_lock_bh(&wqueue->lock);
+	}
+
+	spin_unlock_bh(&wqueue->lock);
+	rcu_read_unlock();
+}
+
+/**
+ * get_watch_queue - Get a watch queue from its file descriptor.
+ * @fd: The fd to query.
+ */
+struct watch_queue *get_watch_queue(int fd)
+{
+	struct pipe_inode_info *pipe;
+	struct watch_queue *wqueue = ERR_PTR(-EINVAL);
+	struct fd f;
+
+	f = fdget(fd);
+	if (f.file) {
+		pipe = get_pipe_info(f.file, false);
+		if (pipe && pipe->watch_queue) {
+			wqueue = pipe->watch_queue;
+			kref_get(&wqueue->usage);
+		}
+		fdput(f);
+	}
+
+	return wqueue;
+}
+EXPORT_SYMBOL(get_watch_queue);
+
+/*
+ * Initialise a watch queue
+ */
+int watch_queue_init(struct pipe_inode_info *pipe)
+{
+	struct watch_queue *wqueue;
+
+	wqueue = kzalloc(sizeof(*wqueue), GFP_KERNEL);
+	if (!wqueue)
+		return -ENOMEM;
+
+	wqueue->pipe = pipe;
+	kref_init(&wqueue->usage);
+	spin_lock_init(&wqueue->lock);
+	INIT_HLIST_HEAD(&wqueue->watches);
+
+	pipe->watch_queue = wqueue;
+	return 0;
+}
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
new file mode 100644
index 000000000..45693fb3e
--- /dev/null
+++ b/kernel/watchdog.c
@@ -0,0 +1,875 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Detect hard and soft lockups on a system
+ *
+ * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
+ *
+ * Note: Most of this code is borrowed heavily from the original softlockup
+ * detector, so thanks to Ingo for the initial implementation.
+ * Some chunks also taken from the old x86-specific nmi watchdog code, thanks
+ * to those contributors as well.
+ */
+
+#define pr_fmt(fmt) "watchdog: " fmt
+
+#include <linux/mm.h>
+#include <linux/cpu.h>
+#include <linux/nmi.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/sysctl.h>
+#include <linux/tick.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/isolation.h>
+#include <linux/stop_machine.h>
+
+#include <asm/irq_regs.h>
+#include <linux/kvm_para.h>
+
+static DEFINE_MUTEX(watchdog_mutex);
+
+#if defined(CONFIG_HARDLOCKUP_DETECTOR) || defined(CONFIG_HAVE_NMI_WATCHDOG)
+# define WATCHDOG_DEFAULT	(SOFT_WATCHDOG_ENABLED | NMI_WATCHDOG_ENABLED)
+# define NMI_WATCHDOG_DEFAULT	1
+#else
+# define WATCHDOG_DEFAULT	(SOFT_WATCHDOG_ENABLED)
+# define NMI_WATCHDOG_DEFAULT	0
+#endif
+
+unsigned long __read_mostly watchdog_enabled;
+int __read_mostly watchdog_user_enabled = 1;
+int __read_mostly nmi_watchdog_user_enabled = NMI_WATCHDOG_DEFAULT;
+int __read_mostly soft_watchdog_user_enabled = 1;
+int __read_mostly watchdog_thresh = 10;
+static int __read_mostly nmi_watchdog_available;
+
+struct cpumask watchdog_cpumask __read_mostly;
+unsigned long *watchdog_cpumask_bits = cpumask_bits(&watchdog_cpumask);
+
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+
+# ifdef CONFIG_SMP
+int __read_mostly sysctl_hardlockup_all_cpu_backtrace;
+# endif /* CONFIG_SMP */
+
+/*
+ * Should we panic when a soft-lockup or hard-lockup occurs:
+ */
+unsigned int __read_mostly hardlockup_panic =
+			IS_ENABLED(CONFIG_BOOTPARAM_HARDLOCKUP_PANIC);
+/*
+ * We may not want to enable hard lockup detection by default in all cases,
+ * for example when running the kernel as a guest on a hypervisor. In these
+ * cases this function can be called to disable hard lockup detection. This
+ * function should only be executed once by the boot processor before the
+ * kernel command line parameters are parsed, because otherwise it is not
+ * possible to override this in hardlockup_panic_setup().
+ */
+void __init hardlockup_detector_disable(void)
+{
+	nmi_watchdog_user_enabled = 0;
+}
+
+static int __init hardlockup_panic_setup(char *str)
+{
+	if (!strncmp(str, "panic", 5))
+		hardlockup_panic = 1;
+	else if (!strncmp(str, "nopanic", 7))
+		hardlockup_panic = 0;
+	else if (!strncmp(str, "0", 1))
+		nmi_watchdog_user_enabled = 0;
+	else if (!strncmp(str, "1", 1))
+		nmi_watchdog_user_enabled = 1;
+	return 1;
+}
+__setup("nmi_watchdog=", hardlockup_panic_setup);
+
+#endif /* CONFIG_HARDLOCKUP_DETECTOR */
+
+/*
+ * These functions can be overridden if an architecture implements its
+ * own hardlockup detector.
+ *
+ * watchdog_nmi_enable/disable can be implemented to start and stop when
+ * softlockup watchdog start and stop. The arch must select the
+ * SOFTLOCKUP_DETECTOR Kconfig.
+ */
+int __weak watchdog_nmi_enable(unsigned int cpu)
+{
+	hardlockup_detector_perf_enable();
+	return 0;
+}
+
+void __weak watchdog_nmi_disable(unsigned int cpu)
+{
+	hardlockup_detector_perf_disable();
+}
+
+/* Return 0, if a NMI watchdog is available. Error code otherwise */
+int __weak __init watchdog_nmi_probe(void)
+{
+	return hardlockup_detector_perf_init();
+}
+
+/**
+ * watchdog_nmi_stop - Stop the watchdog for reconfiguration
+ *
+ * The reconfiguration steps are:
+ * watchdog_nmi_stop();
+ * update_variables();
+ * watchdog_nmi_start();
+ */
+void __weak watchdog_nmi_stop(void) { }
+
+/**
+ * watchdog_nmi_start - Start the watchdog after reconfiguration
+ *
+ * Counterpart to watchdog_nmi_stop().
+ *
+ * The following variables have been updated in update_variables() and
+ * contain the currently valid configuration:
+ * - watchdog_enabled
+ * - watchdog_thresh
+ * - watchdog_cpumask
+ */
+void __weak watchdog_nmi_start(void) { }
+
+/**
+ * lockup_detector_update_enable - Update the sysctl enable bit
+ *
+ * Caller needs to make sure that the NMI/perf watchdogs are off, so this
+ * can't race with watchdog_nmi_disable().
+ */
+static void lockup_detector_update_enable(void)
+{
+	watchdog_enabled = 0;
+	if (!watchdog_user_enabled)
+		return;
+	if (nmi_watchdog_available && nmi_watchdog_user_enabled)
+		watchdog_enabled |= NMI_WATCHDOG_ENABLED;
+	if (soft_watchdog_user_enabled)
+		watchdog_enabled |= SOFT_WATCHDOG_ENABLED;
+}
+
+#ifdef CONFIG_SOFTLOCKUP_DETECTOR
+
+/*
+ * Delay the soflockup report when running a known slow code.
+ * It does _not_ affect the timestamp of the last successdul reschedule.
+ */
+#define SOFTLOCKUP_DELAY_REPORT	ULONG_MAX
+
+#ifdef CONFIG_SMP
+int __read_mostly sysctl_softlockup_all_cpu_backtrace;
+#endif
+
+static struct cpumask watchdog_allowed_mask __read_mostly;
+
+/* Global variables, exported for sysctl */
+unsigned int __read_mostly softlockup_panic =
+			IS_ENABLED(CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC);
+
+static bool softlockup_initialized __read_mostly;
+static u64 __read_mostly sample_period;
+
+/* Timestamp taken after the last successful reschedule. */
+static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
+/* Timestamp of the last softlockup report. */
+static DEFINE_PER_CPU(unsigned long, watchdog_report_ts);
+static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);
+static DEFINE_PER_CPU(bool, softlockup_touch_sync);
+static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts);
+static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
+static unsigned long soft_lockup_nmi_warn;
+
+static int __init softlockup_panic_setup(char *str)
+{
+	softlockup_panic = simple_strtoul(str, NULL, 0);
+	return 1;
+}
+__setup("softlockup_panic=", softlockup_panic_setup);
+
+static int __init nowatchdog_setup(char *str)
+{
+	watchdog_user_enabled = 0;
+	return 1;
+}
+__setup("nowatchdog", nowatchdog_setup);
+
+static int __init nosoftlockup_setup(char *str)
+{
+	soft_watchdog_user_enabled = 0;
+	return 1;
+}
+__setup("nosoftlockup", nosoftlockup_setup);
+
+static int __init watchdog_thresh_setup(char *str)
+{
+	get_option(&str, &watchdog_thresh);
+	return 1;
+}
+__setup("watchdog_thresh=", watchdog_thresh_setup);
+
+static void __lockup_detector_cleanup(void);
+
+/*
+ * Hard-lockup warnings should be triggered after just a few seconds. Soft-
+ * lockups can have false positives under extreme conditions. So we generally
+ * want a higher threshold for soft lockups than for hard lockups. So we couple
+ * the thresholds with a factor: we make the soft threshold twice the amount of
+ * time the hard threshold is.
+ */
+static int get_softlockup_thresh(void)
+{
+	return watchdog_thresh * 2;
+}
+
+/*
+ * Returns seconds, approximately.  We don't need nanosecond
+ * resolution, and we don't need to waste time with a big divide when
+ * 2^30ns == 1.074s.
+ */
+static unsigned long get_timestamp(void)
+{
+	return running_clock() >> 30LL;  /* 2^30 ~= 10^9 */
+}
+
+static void set_sample_period(void)
+{
+	/*
+	 * convert watchdog_thresh from seconds to ns
+	 * the divide by 5 is to give hrtimer several chances (two
+	 * or three with the current relation between the soft
+	 * and hard thresholds) to increment before the
+	 * hardlockup detector generates a warning
+	 */
+	sample_period = get_softlockup_thresh() * ((u64)NSEC_PER_SEC / 5);
+	watchdog_update_hrtimer_threshold(sample_period);
+}
+
+static void update_report_ts(void)
+{
+	__this_cpu_write(watchdog_report_ts, get_timestamp());
+}
+
+/* Commands for resetting the watchdog */
+static void update_touch_ts(void)
+{
+	__this_cpu_write(watchdog_touch_ts, get_timestamp());
+	update_report_ts();
+}
+
+/**
+ * touch_softlockup_watchdog_sched - touch watchdog on scheduler stalls
+ *
+ * Call when the scheduler may have stalled for legitimate reasons
+ * preventing the watchdog task from executing - e.g. the scheduler
+ * entering idle state.  This should only be used for scheduler events.
+ * Use touch_softlockup_watchdog() for everything else.
+ */
+notrace void touch_softlockup_watchdog_sched(void)
+{
+	/*
+	 * Preemption can be enabled.  It doesn't matter which CPU's watchdog
+	 * report period gets restarted here, so use the raw_ operation.
+	 */
+	raw_cpu_write(watchdog_report_ts, SOFTLOCKUP_DELAY_REPORT);
+}
+
+notrace void touch_softlockup_watchdog(void)
+{
+	touch_softlockup_watchdog_sched();
+	wq_watchdog_touch(raw_smp_processor_id());
+}
+EXPORT_SYMBOL(touch_softlockup_watchdog);
+
+void touch_all_softlockup_watchdogs(void)
+{
+	int cpu;
+
+	/*
+	 * watchdog_mutex cannpt be taken here, as this might be called
+	 * from (soft)interrupt context, so the access to
+	 * watchdog_allowed_cpumask might race with a concurrent update.
+	 *
+	 * The watchdog time stamp can race against a concurrent real
+	 * update as well, the only side effect might be a cycle delay for
+	 * the softlockup check.
+	 */
+	for_each_cpu(cpu, &watchdog_allowed_mask) {
+		per_cpu(watchdog_report_ts, cpu) = SOFTLOCKUP_DELAY_REPORT;
+		wq_watchdog_touch(cpu);
+	}
+}
+
+void touch_softlockup_watchdog_sync(void)
+{
+	__this_cpu_write(softlockup_touch_sync, true);
+	__this_cpu_write(watchdog_report_ts, SOFTLOCKUP_DELAY_REPORT);
+}
+
+static int is_softlockup(unsigned long touch_ts,
+			 unsigned long period_ts,
+			 unsigned long now)
+{
+	if ((watchdog_enabled & SOFT_WATCHDOG_ENABLED) && watchdog_thresh){
+		/* Warn about unreasonable delays. */
+		if (time_after(now, period_ts + get_softlockup_thresh()))
+			return now - touch_ts;
+	}
+	return 0;
+}
+
+/* watchdog detector functions */
+bool is_hardlockup(void)
+{
+	unsigned long hrint = __this_cpu_read(hrtimer_interrupts);
+
+	if (__this_cpu_read(hrtimer_interrupts_saved) == hrint)
+		return true;
+
+	__this_cpu_write(hrtimer_interrupts_saved, hrint);
+	return false;
+}
+
+static void watchdog_interrupt_count(void)
+{
+	__this_cpu_inc(hrtimer_interrupts);
+}
+
+static DEFINE_PER_CPU(struct completion, softlockup_completion);
+static DEFINE_PER_CPU(struct cpu_stop_work, softlockup_stop_work);
+
+/*
+ * The watchdog feed function - touches the timestamp.
+ *
+ * It only runs once every sample_period seconds (4 seconds by
+ * default) to reset the softlockup timestamp. If this gets delayed
+ * for more than 2*watchdog_thresh seconds then the debug-printout
+ * triggers in watchdog_timer_fn().
+ */
+static int softlockup_fn(void *data)
+{
+	update_touch_ts();
+	complete(this_cpu_ptr(&softlockup_completion));
+
+	return 0;
+}
+
+/* watchdog kicker functions */
+static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
+{
+	unsigned long touch_ts, period_ts, now;
+	struct pt_regs *regs = get_irq_regs();
+	int duration;
+	int softlockup_all_cpu_backtrace = sysctl_softlockup_all_cpu_backtrace;
+
+	if (!watchdog_enabled)
+		return HRTIMER_NORESTART;
+
+	/* kick the hardlockup detector */
+	watchdog_interrupt_count();
+
+	/* kick the softlockup detector */
+	if (completion_done(this_cpu_ptr(&softlockup_completion))) {
+		reinit_completion(this_cpu_ptr(&softlockup_completion));
+		stop_one_cpu_nowait(smp_processor_id(),
+				softlockup_fn, NULL,
+				this_cpu_ptr(&softlockup_stop_work));
+	}
+
+	/* .. and repeat */
+	hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period));
+
+	/*
+	 * Read the current timestamp first. It might become invalid anytime
+	 * when a virtual machine is stopped by the host or when the watchog
+	 * is touched from NMI.
+	 */
+	now = get_timestamp();
+	/*
+	 * If a virtual machine is stopped by the host it can look to
+	 * the watchdog like a soft lockup. This function touches the watchdog.
+	 */
+	kvm_check_and_clear_guest_paused();
+	/*
+	 * The stored timestamp is comparable with @now only when not touched.
+	 * It might get touched anytime from NMI. Make sure that is_softlockup()
+	 * uses the same (valid) value.
+	 */
+	period_ts = READ_ONCE(*this_cpu_ptr(&watchdog_report_ts));
+
+	/* Reset the interval when touched by known problematic code. */
+	if (period_ts == SOFTLOCKUP_DELAY_REPORT) {
+		if (unlikely(__this_cpu_read(softlockup_touch_sync))) {
+			/*
+			 * If the time stamp was touched atomically
+			 * make sure the scheduler tick is up to date.
+			 */
+			__this_cpu_write(softlockup_touch_sync, false);
+			sched_clock_tick();
+		}
+
+		update_report_ts();
+		return HRTIMER_RESTART;
+	}
+
+	/* Check for a softlockup. */
+	touch_ts = __this_cpu_read(watchdog_touch_ts);
+	duration = is_softlockup(touch_ts, period_ts, now);
+	if (unlikely(duration)) {
+		/*
+		 * Prevent multiple soft-lockup reports if one cpu is already
+		 * engaged in dumping all cpu back traces.
+		 */
+		if (softlockup_all_cpu_backtrace) {
+			if (test_and_set_bit_lock(0, &soft_lockup_nmi_warn))
+				return HRTIMER_RESTART;
+		}
+
+		/* Start period for the next softlockup warning. */
+		update_report_ts();
+
+		pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",
+			smp_processor_id(), duration,
+			current->comm, task_pid_nr(current));
+		print_modules();
+		print_irqtrace_events(current);
+		if (regs)
+			show_regs(regs);
+		else
+			dump_stack();
+
+		if (softlockup_all_cpu_backtrace) {
+			trigger_allbutself_cpu_backtrace();
+			clear_bit_unlock(0, &soft_lockup_nmi_warn);
+		}
+
+		add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK);
+		if (softlockup_panic)
+			panic("softlockup: hung tasks");
+	}
+
+	return HRTIMER_RESTART;
+}
+
+static void watchdog_enable(unsigned int cpu)
+{
+	struct hrtimer *hrtimer = this_cpu_ptr(&watchdog_hrtimer);
+	struct completion *done = this_cpu_ptr(&softlockup_completion);
+
+	WARN_ON_ONCE(cpu != smp_processor_id());
+
+	init_completion(done);
+	complete(done);
+
+	/*
+	 * Start the timer first to prevent the NMI watchdog triggering
+	 * before the timer has a chance to fire.
+	 */
+	hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	hrtimer->function = watchdog_timer_fn;
+	hrtimer_start(hrtimer, ns_to_ktime(sample_period),
+		      HRTIMER_MODE_REL_PINNED_HARD);
+
+	/* Initialize timestamp */
+	update_touch_ts();
+	/* Enable the perf event */
+	if (watchdog_enabled & NMI_WATCHDOG_ENABLED)
+		watchdog_nmi_enable(cpu);
+}
+
+static void watchdog_disable(unsigned int cpu)
+{
+	struct hrtimer *hrtimer = this_cpu_ptr(&watchdog_hrtimer);
+
+	WARN_ON_ONCE(cpu != smp_processor_id());
+
+	/*
+	 * Disable the perf event first. That prevents that a large delay
+	 * between disabling the timer and disabling the perf event causes
+	 * the perf NMI to detect a false positive.
+	 */
+	watchdog_nmi_disable(cpu);
+	hrtimer_cancel(hrtimer);
+	wait_for_completion(this_cpu_ptr(&softlockup_completion));
+}
+
+static int softlockup_stop_fn(void *data)
+{
+	watchdog_disable(smp_processor_id());
+	return 0;
+}
+
+static void softlockup_stop_all(void)
+{
+	int cpu;
+
+	if (!softlockup_initialized)
+		return;
+
+	for_each_cpu(cpu, &watchdog_allowed_mask)
+		smp_call_on_cpu(cpu, softlockup_stop_fn, NULL, false);
+
+	cpumask_clear(&watchdog_allowed_mask);
+}
+
+static int softlockup_start_fn(void *data)
+{
+	watchdog_enable(smp_processor_id());
+	return 0;
+}
+
+static void softlockup_start_all(void)
+{
+	int cpu;
+
+	cpumask_copy(&watchdog_allowed_mask, &watchdog_cpumask);
+	for_each_cpu(cpu, &watchdog_allowed_mask)
+		smp_call_on_cpu(cpu, softlockup_start_fn, NULL, false);
+}
+
+int lockup_detector_online_cpu(unsigned int cpu)
+{
+	if (cpumask_test_cpu(cpu, &watchdog_allowed_mask))
+		watchdog_enable(cpu);
+	return 0;
+}
+
+int lockup_detector_offline_cpu(unsigned int cpu)
+{
+	if (cpumask_test_cpu(cpu, &watchdog_allowed_mask))
+		watchdog_disable(cpu);
+	return 0;
+}
+
+static void __lockup_detector_reconfigure(void)
+{
+	cpus_read_lock();
+	watchdog_nmi_stop();
+
+	softlockup_stop_all();
+	set_sample_period();
+	lockup_detector_update_enable();
+	if (watchdog_enabled && watchdog_thresh)
+		softlockup_start_all();
+
+	watchdog_nmi_start();
+	cpus_read_unlock();
+	/*
+	 * Must be called outside the cpus locked section to prevent
+	 * recursive locking in the perf code.
+	 */
+	__lockup_detector_cleanup();
+}
+
+void lockup_detector_reconfigure(void)
+{
+	mutex_lock(&watchdog_mutex);
+	__lockup_detector_reconfigure();
+	mutex_unlock(&watchdog_mutex);
+}
+
+/*
+ * Create the watchdog infrastructure and configure the detector(s).
+ */
+static __init void lockup_detector_setup(void)
+{
+	/*
+	 * If sysctl is off and watchdog got disabled on the command line,
+	 * nothing to do here.
+	 */
+	lockup_detector_update_enable();
+
+	if (!IS_ENABLED(CONFIG_SYSCTL) &&
+	    !(watchdog_enabled && watchdog_thresh))
+		return;
+
+	mutex_lock(&watchdog_mutex);
+	__lockup_detector_reconfigure();
+	softlockup_initialized = true;
+	mutex_unlock(&watchdog_mutex);
+}
+
+#else /* CONFIG_SOFTLOCKUP_DETECTOR */
+static void __lockup_detector_reconfigure(void)
+{
+	cpus_read_lock();
+	watchdog_nmi_stop();
+	lockup_detector_update_enable();
+	watchdog_nmi_start();
+	cpus_read_unlock();
+}
+void lockup_detector_reconfigure(void)
+{
+	__lockup_detector_reconfigure();
+}
+static inline void lockup_detector_setup(void)
+{
+	__lockup_detector_reconfigure();
+}
+#endif /* !CONFIG_SOFTLOCKUP_DETECTOR */
+
+static void __lockup_detector_cleanup(void)
+{
+	lockdep_assert_held(&watchdog_mutex);
+	hardlockup_detector_perf_cleanup();
+}
+
+/**
+ * lockup_detector_cleanup - Cleanup after cpu hotplug or sysctl changes
+ *
+ * Caller must not hold the cpu hotplug rwsem.
+ */
+void lockup_detector_cleanup(void)
+{
+	mutex_lock(&watchdog_mutex);
+	__lockup_detector_cleanup();
+	mutex_unlock(&watchdog_mutex);
+}
+
+/**
+ * lockup_detector_soft_poweroff - Interface to stop lockup detector(s)
+ *
+ * Special interface for parisc. It prevents lockup detector warnings from
+ * the default pm_poweroff() function which busy loops forever.
+ */
+void lockup_detector_soft_poweroff(void)
+{
+	watchdog_enabled = 0;
+}
+
+#ifdef CONFIG_SYSCTL
+
+/* Propagate any changes to the watchdog infrastructure */
+static void proc_watchdog_update(void)
+{
+	/* Remove impossible cpus to keep sysctl output clean. */
+	cpumask_and(&watchdog_cpumask, &watchdog_cpumask, cpu_possible_mask);
+	__lockup_detector_reconfigure();
+}
+
+/*
+ * common function for watchdog, nmi_watchdog and soft_watchdog parameter
+ *
+ * caller             | table->data points to      | 'which'
+ * -------------------|----------------------------|--------------------------
+ * proc_watchdog      | watchdog_user_enabled      | NMI_WATCHDOG_ENABLED |
+ *                    |                            | SOFT_WATCHDOG_ENABLED
+ * -------------------|----------------------------|--------------------------
+ * proc_nmi_watchdog  | nmi_watchdog_user_enabled  | NMI_WATCHDOG_ENABLED
+ * -------------------|----------------------------|--------------------------
+ * proc_soft_watchdog | soft_watchdog_user_enabled | SOFT_WATCHDOG_ENABLED
+ */
+static int proc_watchdog_common(int which, struct ctl_table *table, int write,
+				void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int err, old, *param = table->data;
+
+	mutex_lock(&watchdog_mutex);
+
+	if (!write) {
+		/*
+		 * On read synchronize the userspace interface. This is a
+		 * racy snapshot.
+		 */
+		*param = (watchdog_enabled & which) != 0;
+		err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+	} else {
+		old = READ_ONCE(*param);
+		err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+		if (!err && old != READ_ONCE(*param))
+			proc_watchdog_update();
+	}
+	mutex_unlock(&watchdog_mutex);
+	return err;
+}
+
+/*
+ * /proc/sys/kernel/watchdog
+ */
+int proc_watchdog(struct ctl_table *table, int write,
+		  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return proc_watchdog_common(NMI_WATCHDOG_ENABLED|SOFT_WATCHDOG_ENABLED,
+				    table, write, buffer, lenp, ppos);
+}
+
+/*
+ * /proc/sys/kernel/nmi_watchdog
+ */
+int proc_nmi_watchdog(struct ctl_table *table, int write,
+		      void *buffer, size_t *lenp, loff_t *ppos)
+{
+	if (!nmi_watchdog_available && write)
+		return -ENOTSUPP;
+	return proc_watchdog_common(NMI_WATCHDOG_ENABLED,
+				    table, write, buffer, lenp, ppos);
+}
+
+/*
+ * /proc/sys/kernel/soft_watchdog
+ */
+int proc_soft_watchdog(struct ctl_table *table, int write,
+			void *buffer, size_t *lenp, loff_t *ppos)
+{
+	return proc_watchdog_common(SOFT_WATCHDOG_ENABLED,
+				    table, write, buffer, lenp, ppos);
+}
+
+/*
+ * /proc/sys/kernel/watchdog_thresh
+ */
+int proc_watchdog_thresh(struct ctl_table *table, int write,
+			 void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int err, old;
+
+	mutex_lock(&watchdog_mutex);
+
+	old = READ_ONCE(watchdog_thresh);
+	err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+
+	if (!err && write && old != READ_ONCE(watchdog_thresh))
+		proc_watchdog_update();
+
+	mutex_unlock(&watchdog_mutex);
+	return err;
+}
+
+/*
+ * The cpumask is the mask of possible cpus that the watchdog can run
+ * on, not the mask of cpus it is actually running on.  This allows the
+ * user to specify a mask that will include cpus that have not yet
+ * been brought online, if desired.
+ */
+int proc_watchdog_cpumask(struct ctl_table *table, int write,
+			  void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int err;
+
+	mutex_lock(&watchdog_mutex);
+
+	err = proc_do_large_bitmap(table, write, buffer, lenp, ppos);
+	if (!err && write)
+		proc_watchdog_update();
+
+	mutex_unlock(&watchdog_mutex);
+	return err;
+}
+
+static const int sixty = 60;
+
+static struct ctl_table watchdog_sysctls[] = {
+	{
+		.procname       = "watchdog",
+		.data		= &watchdog_user_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler   = proc_watchdog,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "watchdog_thresh",
+		.data		= &watchdog_thresh,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_watchdog_thresh,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= (void *)&sixty,
+	},
+	{
+		.procname       = "nmi_watchdog",
+		.data		= &nmi_watchdog_user_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= NMI_WATCHDOG_SYSCTL_PERM,
+		.proc_handler   = proc_nmi_watchdog,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "watchdog_cpumask",
+		.data		= &watchdog_cpumask_bits,
+		.maxlen		= NR_CPUS,
+		.mode		= 0644,
+		.proc_handler	= proc_watchdog_cpumask,
+	},
+#ifdef CONFIG_SOFTLOCKUP_DETECTOR
+	{
+		.procname       = "soft_watchdog",
+		.data		= &soft_watchdog_user_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler   = proc_soft_watchdog,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "softlockup_panic",
+		.data		= &softlockup_panic,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#ifdef CONFIG_SMP
+	{
+		.procname	= "softlockup_all_cpu_backtrace",
+		.data		= &sysctl_softlockup_all_cpu_backtrace,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#endif /* CONFIG_SMP */
+#endif
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+	{
+		.procname	= "hardlockup_panic",
+		.data		= &hardlockup_panic,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#ifdef CONFIG_SMP
+	{
+		.procname	= "hardlockup_all_cpu_backtrace",
+		.data		= &sysctl_hardlockup_all_cpu_backtrace,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#endif /* CONFIG_SMP */
+#endif
+	{}
+};
+
+static void __init watchdog_sysctl_init(void)
+{
+	register_sysctl_init("kernel", watchdog_sysctls);
+}
+#else
+#define watchdog_sysctl_init() do { } while (0)
+#endif /* CONFIG_SYSCTL */
+
+void __init lockup_detector_init(void)
+{
+	if (tick_nohz_full_enabled())
+		pr_info("Disabling watchdog on nohz_full cores by default\n");
+
+	cpumask_copy(&watchdog_cpumask,
+		     housekeeping_cpumask(HK_TYPE_TIMER));
+
+	if (!watchdog_nmi_probe())
+		nmi_watchdog_available = true;
+	lockup_detector_setup();
+	watchdog_sysctl_init();
+}
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
new file mode 100644
index 000000000..1e8a49dc9
--- /dev/null
+++ b/kernel/watchdog_hld.c
@@ -0,0 +1,296 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Detect hard lockups on a system
+ *
+ * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
+ *
+ * Note: Most of this code is borrowed heavily from the original softlockup
+ * detector, so thanks to Ingo for the initial implementation.
+ * Some chunks also taken from the old x86-specific nmi watchdog code, thanks
+ * to those contributors as well.
+ */
+
+#define pr_fmt(fmt) "NMI watchdog: " fmt
+
+#include <linux/nmi.h>
+#include <linux/atomic.h>
+#include <linux/module.h>
+#include <linux/sched/debug.h>
+
+#include <asm/irq_regs.h>
+#include <linux/perf_event.h>
+
+static DEFINE_PER_CPU(bool, hard_watchdog_warn);
+static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
+static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
+static DEFINE_PER_CPU(struct perf_event *, dead_event);
+static struct cpumask dead_events_mask;
+
+static unsigned long hardlockup_allcpu_dumped;
+static atomic_t watchdog_cpus = ATOMIC_INIT(0);
+
+notrace void arch_touch_nmi_watchdog(void)
+{
+	/*
+	 * Using __raw here because some code paths have
+	 * preemption enabled.  If preemption is enabled
+	 * then interrupts should be enabled too, in which
+	 * case we shouldn't have to worry about the watchdog
+	 * going off.
+	 */
+	raw_cpu_write(watchdog_nmi_touch, true);
+}
+EXPORT_SYMBOL(arch_touch_nmi_watchdog);
+
+#ifdef CONFIG_HARDLOCKUP_CHECK_TIMESTAMP
+static DEFINE_PER_CPU(ktime_t, last_timestamp);
+static DEFINE_PER_CPU(unsigned int, nmi_rearmed);
+static ktime_t watchdog_hrtimer_sample_threshold __read_mostly;
+
+void watchdog_update_hrtimer_threshold(u64 period)
+{
+	/*
+	 * The hrtimer runs with a period of (watchdog_threshold * 2) / 5
+	 *
+	 * So it runs effectively with 2.5 times the rate of the NMI
+	 * watchdog. That means the hrtimer should fire 2-3 times before
+	 * the NMI watchdog expires. The NMI watchdog on x86 is based on
+	 * unhalted CPU cycles, so if Turbo-Mode is enabled the CPU cycles
+	 * might run way faster than expected and the NMI fires in a
+	 * smaller period than the one deduced from the nominal CPU
+	 * frequency. Depending on the Turbo-Mode factor this might be fast
+	 * enough to get the NMI period smaller than the hrtimer watchdog
+	 * period and trigger false positives.
+	 *
+	 * The sample threshold is used to check in the NMI handler whether
+	 * the minimum time between two NMI samples has elapsed. That
+	 * prevents false positives.
+	 *
+	 * Set this to 4/5 of the actual watchdog threshold period so the
+	 * hrtimer is guaranteed to fire at least once within the real
+	 * watchdog threshold.
+	 */
+	watchdog_hrtimer_sample_threshold = period * 2;
+}
+
+static bool watchdog_check_timestamp(void)
+{
+	ktime_t delta, now = ktime_get_mono_fast_ns();
+
+	delta = now - __this_cpu_read(last_timestamp);
+	if (delta < watchdog_hrtimer_sample_threshold) {
+		/*
+		 * If ktime is jiffies based, a stalled timer would prevent
+		 * jiffies from being incremented and the filter would look
+		 * at a stale timestamp and never trigger.
+		 */
+		if (__this_cpu_inc_return(nmi_rearmed) < 10)
+			return false;
+	}
+	__this_cpu_write(nmi_rearmed, 0);
+	__this_cpu_write(last_timestamp, now);
+	return true;
+}
+#else
+static inline bool watchdog_check_timestamp(void)
+{
+	return true;
+}
+#endif
+
+static struct perf_event_attr wd_hw_attr = {
+	.type		= PERF_TYPE_HARDWARE,
+	.config		= PERF_COUNT_HW_CPU_CYCLES,
+	.size		= sizeof(struct perf_event_attr),
+	.pinned		= 1,
+	.disabled	= 1,
+};
+
+/* Callback function for perf event subsystem */
+static void watchdog_overflow_callback(struct perf_event *event,
+				       struct perf_sample_data *data,
+				       struct pt_regs *regs)
+{
+	/* Ensure the watchdog never gets throttled */
+	event->hw.interrupts = 0;
+
+	if (!watchdog_check_timestamp())
+		return;
+
+	if (__this_cpu_read(watchdog_nmi_touch) == true) {
+		__this_cpu_write(watchdog_nmi_touch, false);
+		return;
+	}
+
+	/* check for a hardlockup
+	 * This is done by making sure our timer interrupt
+	 * is incrementing.  The timer interrupt should have
+	 * fired multiple times before we overflow'd.  If it hasn't
+	 * then this is a good indication the cpu is stuck
+	 */
+	if (is_hardlockup()) {
+		int this_cpu = smp_processor_id();
+
+		/* only print hardlockups once */
+		if (__this_cpu_read(hard_watchdog_warn) == true)
+			return;
+
+		pr_emerg("Watchdog detected hard LOCKUP on cpu %d\n",
+			 this_cpu);
+		print_modules();
+		print_irqtrace_events(current);
+		if (regs)
+			show_regs(regs);
+		else
+			dump_stack();
+
+		/*
+		 * Perform all-CPU dump only once to avoid multiple hardlockups
+		 * generating interleaving traces
+		 */
+		if (sysctl_hardlockup_all_cpu_backtrace &&
+				!test_and_set_bit(0, &hardlockup_allcpu_dumped))
+			trigger_allbutself_cpu_backtrace();
+
+		if (hardlockup_panic)
+			nmi_panic(regs, "Hard LOCKUP");
+
+		__this_cpu_write(hard_watchdog_warn, true);
+		return;
+	}
+
+	__this_cpu_write(hard_watchdog_warn, false);
+	return;
+}
+
+static int hardlockup_detector_event_create(void)
+{
+	unsigned int cpu = smp_processor_id();
+	struct perf_event_attr *wd_attr;
+	struct perf_event *evt;
+
+	wd_attr = &wd_hw_attr;
+	wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);
+
+	/* Try to register using hardware perf events */
+	evt = perf_event_create_kernel_counter(wd_attr, cpu, NULL,
+					       watchdog_overflow_callback, NULL);
+	if (IS_ERR(evt)) {
+		pr_debug("Perf event create on CPU %d failed with %ld\n", cpu,
+			 PTR_ERR(evt));
+		return PTR_ERR(evt);
+	}
+	this_cpu_write(watchdog_ev, evt);
+	return 0;
+}
+
+/**
+ * hardlockup_detector_perf_enable - Enable the local event
+ */
+void hardlockup_detector_perf_enable(void)
+{
+	if (hardlockup_detector_event_create())
+		return;
+
+	/* use original value for check */
+	if (!atomic_fetch_inc(&watchdog_cpus))
+		pr_info("Enabled. Permanently consumes one hw-PMU counter.\n");
+
+	perf_event_enable(this_cpu_read(watchdog_ev));
+}
+
+/**
+ * hardlockup_detector_perf_disable - Disable the local event
+ */
+void hardlockup_detector_perf_disable(void)
+{
+	struct perf_event *event = this_cpu_read(watchdog_ev);
+
+	if (event) {
+		perf_event_disable(event);
+		this_cpu_write(watchdog_ev, NULL);
+		this_cpu_write(dead_event, event);
+		cpumask_set_cpu(smp_processor_id(), &dead_events_mask);
+		atomic_dec(&watchdog_cpus);
+	}
+}
+
+/**
+ * hardlockup_detector_perf_cleanup - Cleanup disabled events and destroy them
+ *
+ * Called from lockup_detector_cleanup(). Serialized by the caller.
+ */
+void hardlockup_detector_perf_cleanup(void)
+{
+	int cpu;
+
+	for_each_cpu(cpu, &dead_events_mask) {
+		struct perf_event *event = per_cpu(dead_event, cpu);
+
+		/*
+		 * Required because for_each_cpu() reports  unconditionally
+		 * CPU0 as set on UP kernels. Sigh.
+		 */
+		if (event)
+			perf_event_release_kernel(event);
+		per_cpu(dead_event, cpu) = NULL;
+	}
+	cpumask_clear(&dead_events_mask);
+}
+
+/**
+ * hardlockup_detector_perf_stop - Globally stop watchdog events
+ *
+ * Special interface for x86 to handle the perf HT bug.
+ */
+void __init hardlockup_detector_perf_stop(void)
+{
+	int cpu;
+
+	lockdep_assert_cpus_held();
+
+	for_each_online_cpu(cpu) {
+		struct perf_event *event = per_cpu(watchdog_ev, cpu);
+
+		if (event)
+			perf_event_disable(event);
+	}
+}
+
+/**
+ * hardlockup_detector_perf_restart - Globally restart watchdog events
+ *
+ * Special interface for x86 to handle the perf HT bug.
+ */
+void __init hardlockup_detector_perf_restart(void)
+{
+	int cpu;
+
+	lockdep_assert_cpus_held();
+
+	if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED))
+		return;
+
+	for_each_online_cpu(cpu) {
+		struct perf_event *event = per_cpu(watchdog_ev, cpu);
+
+		if (event)
+			perf_event_enable(event);
+	}
+}
+
+/**
+ * hardlockup_detector_perf_init - Probe whether NMI event is available at all
+ */
+int __init hardlockup_detector_perf_init(void)
+{
+	int ret = hardlockup_detector_event_create();
+
+	if (ret) {
+		pr_info("Perf NMI watchdog permanently disabled\n");
+	} else {
+		perf_event_release_kernel(this_cpu_read(watchdog_ev));
+		this_cpu_write(watchdog_ev, NULL);
+	}
+	return ret;
+}
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
new file mode 100644
index 000000000..f3b6ac232
--- /dev/null
+++ b/kernel/workqueue.c
@@ -0,0 +1,6137 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kernel/workqueue.c - generic async execution with shared worker pool
+ *
+ * Copyright (C) 2002		Ingo Molnar
+ *
+ *   Derived from the taskqueue/keventd code by:
+ *     David Woodhouse <dwmw2@infradead.org>
+ *     Andrew Morton
+ *     Kai Petzke <wpp@marie.physik.tu-berlin.de>
+ *     Theodore Ts'o <tytso@mit.edu>
+ *
+ * Made to use alloc_percpu by Christoph Lameter.
+ *
+ * Copyright (C) 2010		SUSE Linux Products GmbH
+ * Copyright (C) 2010		Tejun Heo <tj@kernel.org>
+ *
+ * This is the generic async execution mechanism.  Work items as are
+ * executed in process context.  The worker pool is shared and
+ * automatically managed.  There are two worker pools for each CPU (one for
+ * normal work items and the other for high priority ones) and some extra
+ * pools for workqueues which are not bound to any specific CPU - the
+ * number of these backing pools is dynamic.
+ *
+ * Please read Documentation/core-api/workqueue.rst for details.
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/signal.h>
+#include <linux/completion.h>
+#include <linux/workqueue.h>
+#include <linux/slab.h>
+#include <linux/cpu.h>
+#include <linux/notifier.h>
+#include <linux/kthread.h>
+#include <linux/hardirq.h>
+#include <linux/mempolicy.h>
+#include <linux/freezer.h>
+#include <linux/debug_locks.h>
+#include <linux/lockdep.h>
+#include <linux/idr.h>
+#include <linux/jhash.h>
+#include <linux/hashtable.h>
+#include <linux/rculist.h>
+#include <linux/nodemask.h>
+#include <linux/moduleparam.h>
+#include <linux/uaccess.h>
+#include <linux/sched/isolation.h>
+#include <linux/nmi.h>
+#include <linux/kvm_para.h>
+
+#include "workqueue_internal.h"
+
+enum {
+	/*
+	 * worker_pool flags
+	 *
+	 * A bound pool is either associated or disassociated with its CPU.
+	 * While associated (!DISASSOCIATED), all workers are bound to the
+	 * CPU and none has %WORKER_UNBOUND set and concurrency management
+	 * is in effect.
+	 *
+	 * While DISASSOCIATED, the cpu may be offline and all workers have
+	 * %WORKER_UNBOUND set and concurrency management disabled, and may
+	 * be executing on any CPU.  The pool behaves as an unbound one.
+	 *
+	 * Note that DISASSOCIATED should be flipped only while holding
+	 * wq_pool_attach_mutex to avoid changing binding state while
+	 * worker_attach_to_pool() is in progress.
+	 */
+	POOL_MANAGER_ACTIVE	= 1 << 0,	/* being managed */
+	POOL_DISASSOCIATED	= 1 << 2,	/* cpu can't serve workers */
+
+	/* worker flags */
+	WORKER_DIE		= 1 << 1,	/* die die die */
+	WORKER_IDLE		= 1 << 2,	/* is idle */
+	WORKER_PREP		= 1 << 3,	/* preparing to run works */
+	WORKER_CPU_INTENSIVE	= 1 << 6,	/* cpu intensive */
+	WORKER_UNBOUND		= 1 << 7,	/* worker is unbound */
+	WORKER_REBOUND		= 1 << 8,	/* worker was rebound */
+
+	WORKER_NOT_RUNNING	= WORKER_PREP | WORKER_CPU_INTENSIVE |
+				  WORKER_UNBOUND | WORKER_REBOUND,
+
+	NR_STD_WORKER_POOLS	= 2,		/* # standard pools per cpu */
+
+	UNBOUND_POOL_HASH_ORDER	= 6,		/* hashed by pool->attrs */
+	BUSY_WORKER_HASH_ORDER	= 6,		/* 64 pointers */
+
+	MAX_IDLE_WORKERS_RATIO	= 4,		/* 1/4 of busy can be idle */
+	IDLE_WORKER_TIMEOUT	= 300 * HZ,	/* keep idle ones for 5 mins */
+
+	MAYDAY_INITIAL_TIMEOUT  = HZ / 100 >= 2 ? HZ / 100 : 2,
+						/* call for help after 10ms
+						   (min two ticks) */
+	MAYDAY_INTERVAL		= HZ / 10,	/* and then every 100ms */
+	CREATE_COOLDOWN		= HZ,		/* time to breath after fail */
+
+	/*
+	 * Rescue workers are used only on emergencies and shared by
+	 * all cpus.  Give MIN_NICE.
+	 */
+	RESCUER_NICE_LEVEL	= MIN_NICE,
+	HIGHPRI_NICE_LEVEL	= MIN_NICE,
+
+	WQ_NAME_LEN		= 24,
+};
+
+/*
+ * Structure fields follow one of the following exclusion rules.
+ *
+ * I: Modifiable by initialization/destruction paths and read-only for
+ *    everyone else.
+ *
+ * P: Preemption protected.  Disabling preemption is enough and should
+ *    only be modified and accessed from the local cpu.
+ *
+ * L: pool->lock protected.  Access with pool->lock held.
+ *
+ * X: During normal operation, modification requires pool->lock and should
+ *    be done only from local cpu.  Either disabling preemption on local
+ *    cpu or grabbing pool->lock is enough for read access.  If
+ *    POOL_DISASSOCIATED is set, it's identical to L.
+ *
+ * A: wq_pool_attach_mutex protected.
+ *
+ * PL: wq_pool_mutex protected.
+ *
+ * PR: wq_pool_mutex protected for writes.  RCU protected for reads.
+ *
+ * PW: wq_pool_mutex and wq->mutex protected for writes.  Either for reads.
+ *
+ * PWR: wq_pool_mutex and wq->mutex protected for writes.  Either or
+ *      RCU for reads.
+ *
+ * WQ: wq->mutex protected.
+ *
+ * WR: wq->mutex protected for writes.  RCU protected for reads.
+ *
+ * MD: wq_mayday_lock protected.
+ */
+
+/* struct worker is defined in workqueue_internal.h */
+
+struct worker_pool {
+	raw_spinlock_t		lock;		/* the pool lock */
+	int			cpu;		/* I: the associated cpu */
+	int			node;		/* I: the associated node ID */
+	int			id;		/* I: pool ID */
+	unsigned int		flags;		/* X: flags */
+
+	unsigned long		watchdog_ts;	/* L: watchdog timestamp */
+
+	/*
+	 * The counter is incremented in a process context on the associated CPU
+	 * w/ preemption disabled, and decremented or reset in the same context
+	 * but w/ pool->lock held. The readers grab pool->lock and are
+	 * guaranteed to see if the counter reached zero.
+	 */
+	int			nr_running;
+
+	struct list_head	worklist;	/* L: list of pending works */
+
+	int			nr_workers;	/* L: total number of workers */
+	int			nr_idle;	/* L: currently idle workers */
+
+	struct list_head	idle_list;	/* L: list of idle workers */
+	struct timer_list	idle_timer;	/* L: worker idle timeout */
+	struct timer_list	mayday_timer;	/* L: SOS timer for workers */
+
+	/* a workers is either on busy_hash or idle_list, or the manager */
+	DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
+						/* L: hash of busy workers */
+
+	struct worker		*manager;	/* L: purely informational */
+	struct list_head	workers;	/* A: attached workers */
+	struct completion	*detach_completion; /* all workers detached */
+
+	struct ida		worker_ida;	/* worker IDs for task name */
+
+	struct workqueue_attrs	*attrs;		/* I: worker attributes */
+	struct hlist_node	hash_node;	/* PL: unbound_pool_hash node */
+	int			refcnt;		/* PL: refcnt for unbound pools */
+
+	/*
+	 * Destruction of pool is RCU protected to allow dereferences
+	 * from get_work_pool().
+	 */
+	struct rcu_head		rcu;
+};
+
+/*
+ * The per-pool workqueue.  While queued, the lower WORK_STRUCT_FLAG_BITS
+ * of work_struct->data are used for flags and the remaining high bits
+ * point to the pwq; thus, pwqs need to be aligned at two's power of the
+ * number of flag bits.
+ */
+struct pool_workqueue {
+	struct worker_pool	*pool;		/* I: the associated pool */
+	struct workqueue_struct *wq;		/* I: the owning workqueue */
+	int			work_color;	/* L: current color */
+	int			flush_color;	/* L: flushing color */
+	int			refcnt;		/* L: reference count */
+	int			nr_in_flight[WORK_NR_COLORS];
+						/* L: nr of in_flight works */
+
+	/*
+	 * nr_active management and WORK_STRUCT_INACTIVE:
+	 *
+	 * When pwq->nr_active >= max_active, new work item is queued to
+	 * pwq->inactive_works instead of pool->worklist and marked with
+	 * WORK_STRUCT_INACTIVE.
+	 *
+	 * All work items marked with WORK_STRUCT_INACTIVE do not participate
+	 * in pwq->nr_active and all work items in pwq->inactive_works are
+	 * marked with WORK_STRUCT_INACTIVE.  But not all WORK_STRUCT_INACTIVE
+	 * work items are in pwq->inactive_works.  Some of them are ready to
+	 * run in pool->worklist or worker->scheduled.  Those work itmes are
+	 * only struct wq_barrier which is used for flush_work() and should
+	 * not participate in pwq->nr_active.  For non-barrier work item, it
+	 * is marked with WORK_STRUCT_INACTIVE iff it is in pwq->inactive_works.
+	 */
+	int			nr_active;	/* L: nr of active works */
+	int			max_active;	/* L: max active works */
+	struct list_head	inactive_works;	/* L: inactive works */
+	struct list_head	pwqs_node;	/* WR: node on wq->pwqs */
+	struct list_head	mayday_node;	/* MD: node on wq->maydays */
+
+	/*
+	 * Release of unbound pwq is punted to system_wq.  See put_pwq()
+	 * and pwq_unbound_release_workfn() for details.  pool_workqueue
+	 * itself is also RCU protected so that the first pwq can be
+	 * determined without grabbing wq->mutex.
+	 */
+	struct work_struct	unbound_release_work;
+	struct rcu_head		rcu;
+} __aligned(1 << WORK_STRUCT_FLAG_BITS);
+
+/*
+ * Structure used to wait for workqueue flush.
+ */
+struct wq_flusher {
+	struct list_head	list;		/* WQ: list of flushers */
+	int			flush_color;	/* WQ: flush color waiting for */
+	struct completion	done;		/* flush completion */
+};
+
+struct wq_device;
+
+/*
+ * The externally visible workqueue.  It relays the issued work items to
+ * the appropriate worker_pool through its pool_workqueues.
+ */
+struct workqueue_struct {
+	struct list_head	pwqs;		/* WR: all pwqs of this wq */
+	struct list_head	list;		/* PR: list of all workqueues */
+
+	struct mutex		mutex;		/* protects this wq */
+	int			work_color;	/* WQ: current work color */
+	int			flush_color;	/* WQ: current flush color */
+	atomic_t		nr_pwqs_to_flush; /* flush in progress */
+	struct wq_flusher	*first_flusher;	/* WQ: first flusher */
+	struct list_head	flusher_queue;	/* WQ: flush waiters */
+	struct list_head	flusher_overflow; /* WQ: flush overflow list */
+
+	struct list_head	maydays;	/* MD: pwqs requesting rescue */
+	struct worker		*rescuer;	/* MD: rescue worker */
+
+	int			nr_drainers;	/* WQ: drain in progress */
+	int			saved_max_active; /* WQ: saved pwq max_active */
+
+	struct workqueue_attrs	*unbound_attrs;	/* PW: only for unbound wqs */
+	struct pool_workqueue	*dfl_pwq;	/* PW: only for unbound wqs */
+
+#ifdef CONFIG_SYSFS
+	struct wq_device	*wq_dev;	/* I: for sysfs interface */
+#endif
+#ifdef CONFIG_LOCKDEP
+	char			*lock_name;
+	struct lock_class_key	key;
+	struct lockdep_map	lockdep_map;
+#endif
+	char			name[WQ_NAME_LEN]; /* I: workqueue name */
+
+	/*
+	 * Destruction of workqueue_struct is RCU protected to allow walking
+	 * the workqueues list without grabbing wq_pool_mutex.
+	 * This is used to dump all workqueues from sysrq.
+	 */
+	struct rcu_head		rcu;
+
+	/* hot fields used during command issue, aligned to cacheline */
+	unsigned int		flags ____cacheline_aligned; /* WQ: WQ_* flags */
+	struct pool_workqueue __percpu *cpu_pwqs; /* I: per-cpu pwqs */
+	struct pool_workqueue __rcu *numa_pwq_tbl[]; /* PWR: unbound pwqs indexed by node */
+};
+
+static struct kmem_cache *pwq_cache;
+
+static cpumask_var_t *wq_numa_possible_cpumask;
+					/* possible CPUs of each node */
+
+static bool wq_disable_numa;
+module_param_named(disable_numa, wq_disable_numa, bool, 0444);
+
+/* see the comment above the definition of WQ_POWER_EFFICIENT */
+static bool wq_power_efficient = IS_ENABLED(CONFIG_WQ_POWER_EFFICIENT_DEFAULT);
+module_param_named(power_efficient, wq_power_efficient, bool, 0444);
+
+static bool wq_online;			/* can kworkers be created yet? */
+
+static bool wq_numa_enabled;		/* unbound NUMA affinity enabled */
+
+/* buf for wq_update_unbound_numa_attrs(), protected by CPU hotplug exclusion */
+static struct workqueue_attrs *wq_update_unbound_numa_attrs_buf;
+
+static DEFINE_MUTEX(wq_pool_mutex);	/* protects pools and workqueues list */
+static DEFINE_MUTEX(wq_pool_attach_mutex); /* protects worker attach/detach */
+static DEFINE_RAW_SPINLOCK(wq_mayday_lock);	/* protects wq->maydays list */
+/* wait for manager to go away */
+static struct rcuwait manager_wait = __RCUWAIT_INITIALIZER(manager_wait);
+
+static LIST_HEAD(workqueues);		/* PR: list of all workqueues */
+static bool workqueue_freezing;		/* PL: have wqs started freezing? */
+
+/* PL&A: allowable cpus for unbound wqs and work items */
+static cpumask_var_t wq_unbound_cpumask;
+
+/* CPU where unbound work was last round robin scheduled from this CPU */
+static DEFINE_PER_CPU(int, wq_rr_cpu_last);
+
+/*
+ * Local execution of unbound work items is no longer guaranteed.  The
+ * following always forces round-robin CPU selection on unbound work items
+ * to uncover usages which depend on it.
+ */
+#ifdef CONFIG_DEBUG_WQ_FORCE_RR_CPU
+static bool wq_debug_force_rr_cpu = true;
+#else
+static bool wq_debug_force_rr_cpu = false;
+#endif
+module_param_named(debug_force_rr_cpu, wq_debug_force_rr_cpu, bool, 0644);
+
+/* the per-cpu worker pools */
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS], cpu_worker_pools);
+
+static DEFINE_IDR(worker_pool_idr);	/* PR: idr of all pools */
+
+/* PL: hash of all unbound pools keyed by pool->attrs */
+static DEFINE_HASHTABLE(unbound_pool_hash, UNBOUND_POOL_HASH_ORDER);
+
+/* I: attributes used when instantiating standard unbound pools on demand */
+static struct workqueue_attrs *unbound_std_wq_attrs[NR_STD_WORKER_POOLS];
+
+/* I: attributes used when instantiating ordered pools on demand */
+static struct workqueue_attrs *ordered_wq_attrs[NR_STD_WORKER_POOLS];
+
+struct workqueue_struct *system_wq __read_mostly;
+EXPORT_SYMBOL(system_wq);
+struct workqueue_struct *system_highpri_wq __read_mostly;
+EXPORT_SYMBOL_GPL(system_highpri_wq);
+struct workqueue_struct *system_long_wq __read_mostly;
+EXPORT_SYMBOL_GPL(system_long_wq);
+struct workqueue_struct *system_unbound_wq __read_mostly;
+EXPORT_SYMBOL_GPL(system_unbound_wq);
+struct workqueue_struct *system_freezable_wq __read_mostly;
+EXPORT_SYMBOL_GPL(system_freezable_wq);
+struct workqueue_struct *system_power_efficient_wq __read_mostly;
+EXPORT_SYMBOL_GPL(system_power_efficient_wq);
+struct workqueue_struct *system_freezable_power_efficient_wq __read_mostly;
+EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq);
+
+static int worker_thread(void *__worker);
+static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
+static void show_pwq(struct pool_workqueue *pwq);
+static void show_one_worker_pool(struct worker_pool *pool);
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/workqueue.h>
+
+#define assert_rcu_or_pool_mutex()					\
+	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
+			 !lockdep_is_held(&wq_pool_mutex),		\
+			 "RCU or wq_pool_mutex should be held")
+
+#define assert_rcu_or_wq_mutex_or_pool_mutex(wq)			\
+	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
+			 !lockdep_is_held(&wq->mutex) &&		\
+			 !lockdep_is_held(&wq_pool_mutex),		\
+			 "RCU, wq->mutex or wq_pool_mutex should be held")
+
+#define for_each_cpu_worker_pool(pool, cpu)				\
+	for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0];		\
+	     (pool) < &per_cpu(cpu_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \
+	     (pool)++)
+
+/**
+ * for_each_pool - iterate through all worker_pools in the system
+ * @pool: iteration cursor
+ * @pi: integer used for iteration
+ *
+ * This must be called either with wq_pool_mutex held or RCU read
+ * locked.  If the pool needs to be used beyond the locking in effect, the
+ * caller is responsible for guaranteeing that the pool stays online.
+ *
+ * The if/else clause exists only for the lockdep assertion and can be
+ * ignored.
+ */
+#define for_each_pool(pool, pi)						\
+	idr_for_each_entry(&worker_pool_idr, pool, pi)			\
+		if (({ assert_rcu_or_pool_mutex(); false; })) { }	\
+		else
+
+/**
+ * for_each_pool_worker - iterate through all workers of a worker_pool
+ * @worker: iteration cursor
+ * @pool: worker_pool to iterate workers of
+ *
+ * This must be called with wq_pool_attach_mutex.
+ *
+ * The if/else clause exists only for the lockdep assertion and can be
+ * ignored.
+ */
+#define for_each_pool_worker(worker, pool)				\
+	list_for_each_entry((worker), &(pool)->workers, node)		\
+		if (({ lockdep_assert_held(&wq_pool_attach_mutex); false; })) { } \
+		else
+
+/**
+ * for_each_pwq - iterate through all pool_workqueues of the specified workqueue
+ * @pwq: iteration cursor
+ * @wq: the target workqueue
+ *
+ * This must be called either with wq->mutex held or RCU read locked.
+ * If the pwq needs to be used beyond the locking in effect, the caller is
+ * responsible for guaranteeing that the pwq stays online.
+ *
+ * The if/else clause exists only for the lockdep assertion and can be
+ * ignored.
+ */
+#define for_each_pwq(pwq, wq)						\
+	list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node,		\
+				 lockdep_is_held(&(wq->mutex)))
+
+#ifdef CONFIG_DEBUG_OBJECTS_WORK
+
+static const struct debug_obj_descr work_debug_descr;
+
+static void *work_debug_hint(void *addr)
+{
+	return ((struct work_struct *) addr)->func;
+}
+
+static bool work_is_static_object(void *addr)
+{
+	struct work_struct *work = addr;
+
+	return test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work));
+}
+
+/*
+ * fixup_init is called when:
+ * - an active object is initialized
+ */
+static bool work_fixup_init(void *addr, enum debug_obj_state state)
+{
+	struct work_struct *work = addr;
+
+	switch (state) {
+	case ODEBUG_STATE_ACTIVE:
+		cancel_work_sync(work);
+		debug_object_init(work, &work_debug_descr);
+		return true;
+	default:
+		return false;
+	}
+}
+
+/*
+ * fixup_free is called when:
+ * - an active object is freed
+ */
+static bool work_fixup_free(void *addr, enum debug_obj_state state)
+{
+	struct work_struct *work = addr;
+
+	switch (state) {
+	case ODEBUG_STATE_ACTIVE:
+		cancel_work_sync(work);
+		debug_object_free(work, &work_debug_descr);
+		return true;
+	default:
+		return false;
+	}
+}
+
+static const struct debug_obj_descr work_debug_descr = {
+	.name		= "work_struct",
+	.debug_hint	= work_debug_hint,
+	.is_static_object = work_is_static_object,
+	.fixup_init	= work_fixup_init,
+	.fixup_free	= work_fixup_free,
+};
+
+static inline void debug_work_activate(struct work_struct *work)
+{
+	debug_object_activate(work, &work_debug_descr);
+}
+
+static inline void debug_work_deactivate(struct work_struct *work)
+{
+	debug_object_deactivate(work, &work_debug_descr);
+}
+
+void __init_work(struct work_struct *work, int onstack)
+{
+	if (onstack)
+		debug_object_init_on_stack(work, &work_debug_descr);
+	else
+		debug_object_init(work, &work_debug_descr);
+}
+EXPORT_SYMBOL_GPL(__init_work);
+
+void destroy_work_on_stack(struct work_struct *work)
+{
+	debug_object_free(work, &work_debug_descr);
+}
+EXPORT_SYMBOL_GPL(destroy_work_on_stack);
+
+void destroy_delayed_work_on_stack(struct delayed_work *work)
+{
+	destroy_timer_on_stack(&work->timer);
+	debug_object_free(&work->work, &work_debug_descr);
+}
+EXPORT_SYMBOL_GPL(destroy_delayed_work_on_stack);
+
+#else
+static inline void debug_work_activate(struct work_struct *work) { }
+static inline void debug_work_deactivate(struct work_struct *work) { }
+#endif
+
+/**
+ * worker_pool_assign_id - allocate ID and assign it to @pool
+ * @pool: the pool pointer of interest
+ *
+ * Returns 0 if ID in [0, WORK_OFFQ_POOL_NONE) is allocated and assigned
+ * successfully, -errno on failure.
+ */
+static int worker_pool_assign_id(struct worker_pool *pool)
+{
+	int ret;
+
+	lockdep_assert_held(&wq_pool_mutex);
+
+	ret = idr_alloc(&worker_pool_idr, pool, 0, WORK_OFFQ_POOL_NONE,
+			GFP_KERNEL);
+	if (ret >= 0) {
+		pool->id = ret;
+		return 0;
+	}
+	return ret;
+}
+
+/**
+ * unbound_pwq_by_node - return the unbound pool_workqueue for the given node
+ * @wq: the target workqueue
+ * @node: the node ID
+ *
+ * This must be called with any of wq_pool_mutex, wq->mutex or RCU
+ * read locked.
+ * If the pwq needs to be used beyond the locking in effect, the caller is
+ * responsible for guaranteeing that the pwq stays online.
+ *
+ * Return: The unbound pool_workqueue for @node.
+ */
+static struct pool_workqueue *unbound_pwq_by_node(struct workqueue_struct *wq,
+						  int node)
+{
+	assert_rcu_or_wq_mutex_or_pool_mutex(wq);
+
+	/*
+	 * XXX: @node can be NUMA_NO_NODE if CPU goes offline while a
+	 * delayed item is pending.  The plan is to keep CPU -> NODE
+	 * mapping valid and stable across CPU on/offlines.  Once that
+	 * happens, this workaround can be removed.
+	 */
+	if (unlikely(node == NUMA_NO_NODE))
+		return wq->dfl_pwq;
+
+	return rcu_dereference_raw(wq->numa_pwq_tbl[node]);
+}
+
+static unsigned int work_color_to_flags(int color)
+{
+	return color << WORK_STRUCT_COLOR_SHIFT;
+}
+
+static int get_work_color(unsigned long work_data)
+{
+	return (work_data >> WORK_STRUCT_COLOR_SHIFT) &
+		((1 << WORK_STRUCT_COLOR_BITS) - 1);
+}
+
+static int work_next_color(int color)
+{
+	return (color + 1) % WORK_NR_COLORS;
+}
+
+/*
+ * While queued, %WORK_STRUCT_PWQ is set and non flag bits of a work's data
+ * contain the pointer to the queued pwq.  Once execution starts, the flag
+ * is cleared and the high bits contain OFFQ flags and pool ID.
+ *
+ * set_work_pwq(), set_work_pool_and_clear_pending(), mark_work_canceling()
+ * and clear_work_data() can be used to set the pwq, pool or clear
+ * work->data.  These functions should only be called while the work is
+ * owned - ie. while the PENDING bit is set.
+ *
+ * get_work_pool() and get_work_pwq() can be used to obtain the pool or pwq
+ * corresponding to a work.  Pool is available once the work has been
+ * queued anywhere after initialization until it is sync canceled.  pwq is
+ * available only while the work item is queued.
+ *
+ * %WORK_OFFQ_CANCELING is used to mark a work item which is being
+ * canceled.  While being canceled, a work item may have its PENDING set
+ * but stay off timer and worklist for arbitrarily long and nobody should
+ * try to steal the PENDING bit.
+ */
+static inline void set_work_data(struct work_struct *work, unsigned long data,
+				 unsigned long flags)
+{
+	WARN_ON_ONCE(!work_pending(work));
+	atomic_long_set(&work->data, data | flags | work_static(work));
+}
+
+static void set_work_pwq(struct work_struct *work, struct pool_workqueue *pwq,
+			 unsigned long extra_flags)
+{
+	set_work_data(work, (unsigned long)pwq,
+		      WORK_STRUCT_PENDING | WORK_STRUCT_PWQ | extra_flags);
+}
+
+static void set_work_pool_and_keep_pending(struct work_struct *work,
+					   int pool_id)
+{
+	set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT,
+		      WORK_STRUCT_PENDING);
+}
+
+static void set_work_pool_and_clear_pending(struct work_struct *work,
+					    int pool_id)
+{
+	/*
+	 * The following wmb is paired with the implied mb in
+	 * test_and_set_bit(PENDING) and ensures all updates to @work made
+	 * here are visible to and precede any updates by the next PENDING
+	 * owner.
+	 */
+	smp_wmb();
+	set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, 0);
+	/*
+	 * The following mb guarantees that previous clear of a PENDING bit
+	 * will not be reordered with any speculative LOADS or STORES from
+	 * work->current_func, which is executed afterwards.  This possible
+	 * reordering can lead to a missed execution on attempt to queue
+	 * the same @work.  E.g. consider this case:
+	 *
+	 *   CPU#0                         CPU#1
+	 *   ----------------------------  --------------------------------
+	 *
+	 * 1  STORE event_indicated
+	 * 2  queue_work_on() {
+	 * 3    test_and_set_bit(PENDING)
+	 * 4 }                             set_..._and_clear_pending() {
+	 * 5                                 set_work_data() # clear bit
+	 * 6                                 smp_mb()
+	 * 7                               work->current_func() {
+	 * 8				      LOAD event_indicated
+	 *				   }
+	 *
+	 * Without an explicit full barrier speculative LOAD on line 8 can
+	 * be executed before CPU#0 does STORE on line 1.  If that happens,
+	 * CPU#0 observes the PENDING bit is still set and new execution of
+	 * a @work is not queued in a hope, that CPU#1 will eventually
+	 * finish the queued @work.  Meanwhile CPU#1 does not see
+	 * event_indicated is set, because speculative LOAD was executed
+	 * before actual STORE.
+	 */
+	smp_mb();
+}
+
+static void clear_work_data(struct work_struct *work)
+{
+	smp_wmb();	/* see set_work_pool_and_clear_pending() */
+	set_work_data(work, WORK_STRUCT_NO_POOL, 0);
+}
+
+static inline struct pool_workqueue *work_struct_pwq(unsigned long data)
+{
+	return (struct pool_workqueue *)(data & WORK_STRUCT_WQ_DATA_MASK);
+}
+
+static struct pool_workqueue *get_work_pwq(struct work_struct *work)
+{
+	unsigned long data = atomic_long_read(&work->data);
+
+	if (data & WORK_STRUCT_PWQ)
+		return work_struct_pwq(data);
+	else
+		return NULL;
+}
+
+/**
+ * get_work_pool - return the worker_pool a given work was associated with
+ * @work: the work item of interest
+ *
+ * Pools are created and destroyed under wq_pool_mutex, and allows read
+ * access under RCU read lock.  As such, this function should be
+ * called under wq_pool_mutex or inside of a rcu_read_lock() region.
+ *
+ * All fields of the returned pool are accessible as long as the above
+ * mentioned locking is in effect.  If the returned pool needs to be used
+ * beyond the critical section, the caller is responsible for ensuring the
+ * returned pool is and stays online.
+ *
+ * Return: The worker_pool @work was last associated with.  %NULL if none.
+ */
+static struct worker_pool *get_work_pool(struct work_struct *work)
+{
+	unsigned long data = atomic_long_read(&work->data);
+	int pool_id;
+
+	assert_rcu_or_pool_mutex();
+
+	if (data & WORK_STRUCT_PWQ)
+		return work_struct_pwq(data)->pool;
+
+	pool_id = data >> WORK_OFFQ_POOL_SHIFT;
+	if (pool_id == WORK_OFFQ_POOL_NONE)
+		return NULL;
+
+	return idr_find(&worker_pool_idr, pool_id);
+}
+
+/**
+ * get_work_pool_id - return the worker pool ID a given work is associated with
+ * @work: the work item of interest
+ *
+ * Return: The worker_pool ID @work was last associated with.
+ * %WORK_OFFQ_POOL_NONE if none.
+ */
+static int get_work_pool_id(struct work_struct *work)
+{
+	unsigned long data = atomic_long_read(&work->data);
+
+	if (data & WORK_STRUCT_PWQ)
+		return work_struct_pwq(data)->pool->id;
+
+	return data >> WORK_OFFQ_POOL_SHIFT;
+}
+
+static void mark_work_canceling(struct work_struct *work)
+{
+	unsigned long pool_id = get_work_pool_id(work);
+
+	pool_id <<= WORK_OFFQ_POOL_SHIFT;
+	set_work_data(work, pool_id | WORK_OFFQ_CANCELING, WORK_STRUCT_PENDING);
+}
+
+static bool work_is_canceling(struct work_struct *work)
+{
+	unsigned long data = atomic_long_read(&work->data);
+
+	return !(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_CANCELING);
+}
+
+/*
+ * Policy functions.  These define the policies on how the global worker
+ * pools are managed.  Unless noted otherwise, these functions assume that
+ * they're being called with pool->lock held.
+ */
+
+static bool __need_more_worker(struct worker_pool *pool)
+{
+	return !pool->nr_running;
+}
+
+/*
+ * Need to wake up a worker?  Called from anything but currently
+ * running workers.
+ *
+ * Note that, because unbound workers never contribute to nr_running, this
+ * function will always return %true for unbound pools as long as the
+ * worklist isn't empty.
+ */
+static bool need_more_worker(struct worker_pool *pool)
+{
+	return !list_empty(&pool->worklist) && __need_more_worker(pool);
+}
+
+/* Can I start working?  Called from busy but !running workers. */
+static bool may_start_working(struct worker_pool *pool)
+{
+	return pool->nr_idle;
+}
+
+/* Do I need to keep working?  Called from currently running workers. */
+static bool keep_working(struct worker_pool *pool)
+{
+	return !list_empty(&pool->worklist) && (pool->nr_running <= 1);
+}
+
+/* Do we need a new worker?  Called from manager. */
+static bool need_to_create_worker(struct worker_pool *pool)
+{
+	return need_more_worker(pool) && !may_start_working(pool);
+}
+
+/* Do we have too many workers and should some go away? */
+static bool too_many_workers(struct worker_pool *pool)
+{
+	bool managing = pool->flags & POOL_MANAGER_ACTIVE;
+	int nr_idle = pool->nr_idle + managing; /* manager is considered idle */
+	int nr_busy = pool->nr_workers - nr_idle;
+
+	return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy;
+}
+
+/*
+ * Wake up functions.
+ */
+
+/* Return the first idle worker.  Called with pool->lock held. */
+static struct worker *first_idle_worker(struct worker_pool *pool)
+{
+	if (unlikely(list_empty(&pool->idle_list)))
+		return NULL;
+
+	return list_first_entry(&pool->idle_list, struct worker, entry);
+}
+
+/**
+ * wake_up_worker - wake up an idle worker
+ * @pool: worker pool to wake worker from
+ *
+ * Wake up the first idle worker of @pool.
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(pool->lock).
+ */
+static void wake_up_worker(struct worker_pool *pool)
+{
+	struct worker *worker = first_idle_worker(pool);
+
+	if (likely(worker))
+		wake_up_process(worker->task);
+}
+
+/**
+ * wq_worker_running - a worker is running again
+ * @task: task waking up
+ *
+ * This function is called when a worker returns from schedule()
+ */
+void wq_worker_running(struct task_struct *task)
+{
+	struct worker *worker = kthread_data(task);
+
+	if (!worker->sleeping)
+		return;
+
+	/*
+	 * If preempted by unbind_workers() between the WORKER_NOT_RUNNING check
+	 * and the nr_running increment below, we may ruin the nr_running reset
+	 * and leave with an unexpected pool->nr_running == 1 on the newly unbound
+	 * pool. Protect against such race.
+	 */
+	preempt_disable();
+	if (!(worker->flags & WORKER_NOT_RUNNING))
+		worker->pool->nr_running++;
+	preempt_enable();
+	worker->sleeping = 0;
+}
+
+/**
+ * wq_worker_sleeping - a worker is going to sleep
+ * @task: task going to sleep
+ *
+ * This function is called from schedule() when a busy worker is
+ * going to sleep.
+ */
+void wq_worker_sleeping(struct task_struct *task)
+{
+	struct worker *worker = kthread_data(task);
+	struct worker_pool *pool;
+
+	/*
+	 * Rescuers, which may not have all the fields set up like normal
+	 * workers, also reach here, let's not access anything before
+	 * checking NOT_RUNNING.
+	 */
+	if (worker->flags & WORKER_NOT_RUNNING)
+		return;
+
+	pool = worker->pool;
+
+	/* Return if preempted before wq_worker_running() was reached */
+	if (worker->sleeping)
+		return;
+
+	worker->sleeping = 1;
+	raw_spin_lock_irq(&pool->lock);
+
+	/*
+	 * Recheck in case unbind_workers() preempted us. We don't
+	 * want to decrement nr_running after the worker is unbound
+	 * and nr_running has been reset.
+	 */
+	if (worker->flags & WORKER_NOT_RUNNING) {
+		raw_spin_unlock_irq(&pool->lock);
+		return;
+	}
+
+	pool->nr_running--;
+	if (need_more_worker(pool))
+		wake_up_worker(pool);
+	raw_spin_unlock_irq(&pool->lock);
+}
+
+/**
+ * wq_worker_last_func - retrieve worker's last work function
+ * @task: Task to retrieve last work function of.
+ *
+ * Determine the last function a worker executed. This is called from
+ * the scheduler to get a worker's last known identity.
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(rq->lock)
+ *
+ * This function is called during schedule() when a kworker is going
+ * to sleep. It's used by psi to identify aggregation workers during
+ * dequeuing, to allow periodic aggregation to shut-off when that
+ * worker is the last task in the system or cgroup to go to sleep.
+ *
+ * As this function doesn't involve any workqueue-related locking, it
+ * only returns stable values when called from inside the scheduler's
+ * queuing and dequeuing paths, when @task, which must be a kworker,
+ * is guaranteed to not be processing any works.
+ *
+ * Return:
+ * The last work function %current executed as a worker, NULL if it
+ * hasn't executed any work yet.
+ */
+work_func_t wq_worker_last_func(struct task_struct *task)
+{
+	struct worker *worker = kthread_data(task);
+
+	return worker->last_func;
+}
+
+/**
+ * worker_set_flags - set worker flags and adjust nr_running accordingly
+ * @worker: self
+ * @flags: flags to set
+ *
+ * Set @flags in @worker->flags and adjust nr_running accordingly.
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(pool->lock)
+ */
+static inline void worker_set_flags(struct worker *worker, unsigned int flags)
+{
+	struct worker_pool *pool = worker->pool;
+
+	WARN_ON_ONCE(worker->task != current);
+
+	/* If transitioning into NOT_RUNNING, adjust nr_running. */
+	if ((flags & WORKER_NOT_RUNNING) &&
+	    !(worker->flags & WORKER_NOT_RUNNING)) {
+		pool->nr_running--;
+	}
+
+	worker->flags |= flags;
+}
+
+/**
+ * worker_clr_flags - clear worker flags and adjust nr_running accordingly
+ * @worker: self
+ * @flags: flags to clear
+ *
+ * Clear @flags in @worker->flags and adjust nr_running accordingly.
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(pool->lock)
+ */
+static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
+{
+	struct worker_pool *pool = worker->pool;
+	unsigned int oflags = worker->flags;
+
+	WARN_ON_ONCE(worker->task != current);
+
+	worker->flags &= ~flags;
+
+	/*
+	 * If transitioning out of NOT_RUNNING, increment nr_running.  Note
+	 * that the nested NOT_RUNNING is not a noop.  NOT_RUNNING is mask
+	 * of multiple flags, not a single flag.
+	 */
+	if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING))
+		if (!(worker->flags & WORKER_NOT_RUNNING))
+			pool->nr_running++;
+}
+
+/**
+ * find_worker_executing_work - find worker which is executing a work
+ * @pool: pool of interest
+ * @work: work to find worker for
+ *
+ * Find a worker which is executing @work on @pool by searching
+ * @pool->busy_hash which is keyed by the address of @work.  For a worker
+ * to match, its current execution should match the address of @work and
+ * its work function.  This is to avoid unwanted dependency between
+ * unrelated work executions through a work item being recycled while still
+ * being executed.
+ *
+ * This is a bit tricky.  A work item may be freed once its execution
+ * starts and nothing prevents the freed area from being recycled for
+ * another work item.  If the same work item address ends up being reused
+ * before the original execution finishes, workqueue will identify the
+ * recycled work item as currently executing and make it wait until the
+ * current execution finishes, introducing an unwanted dependency.
+ *
+ * This function checks the work item address and work function to avoid
+ * false positives.  Note that this isn't complete as one may construct a
+ * work function which can introduce dependency onto itself through a
+ * recycled work item.  Well, if somebody wants to shoot oneself in the
+ * foot that badly, there's only so much we can do, and if such deadlock
+ * actually occurs, it should be easy to locate the culprit work function.
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(pool->lock).
+ *
+ * Return:
+ * Pointer to worker which is executing @work if found, %NULL
+ * otherwise.
+ */
+static struct worker *find_worker_executing_work(struct worker_pool *pool,
+						 struct work_struct *work)
+{
+	struct worker *worker;
+
+	hash_for_each_possible(pool->busy_hash, worker, hentry,
+			       (unsigned long)work)
+		if (worker->current_work == work &&
+		    worker->current_func == work->func)
+			return worker;
+
+	return NULL;
+}
+
+/**
+ * move_linked_works - move linked works to a list
+ * @work: start of series of works to be scheduled
+ * @head: target list to append @work to
+ * @nextp: out parameter for nested worklist walking
+ *
+ * Schedule linked works starting from @work to @head.  Work series to
+ * be scheduled starts at @work and includes any consecutive work with
+ * WORK_STRUCT_LINKED set in its predecessor.
+ *
+ * If @nextp is not NULL, it's updated to point to the next work of
+ * the last scheduled work.  This allows move_linked_works() to be
+ * nested inside outer list_for_each_entry_safe().
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(pool->lock).
+ */
+static void move_linked_works(struct work_struct *work, struct list_head *head,
+			      struct work_struct **nextp)
+{
+	struct work_struct *n;
+
+	/*
+	 * Linked worklist will always end before the end of the list,
+	 * use NULL for list head.
+	 */
+	list_for_each_entry_safe_from(work, n, NULL, entry) {
+		list_move_tail(&work->entry, head);
+		if (!(*work_data_bits(work) & WORK_STRUCT_LINKED))
+			break;
+	}
+
+	/*
+	 * If we're already inside safe list traversal and have moved
+	 * multiple works to the scheduled queue, the next position
+	 * needs to be updated.
+	 */
+	if (nextp)
+		*nextp = n;
+}
+
+/**
+ * get_pwq - get an extra reference on the specified pool_workqueue
+ * @pwq: pool_workqueue to get
+ *
+ * Obtain an extra reference on @pwq.  The caller should guarantee that
+ * @pwq has positive refcnt and be holding the matching pool->lock.
+ */
+static void get_pwq(struct pool_workqueue *pwq)
+{
+	lockdep_assert_held(&pwq->pool->lock);
+	WARN_ON_ONCE(pwq->refcnt <= 0);
+	pwq->refcnt++;
+}
+
+/**
+ * put_pwq - put a pool_workqueue reference
+ * @pwq: pool_workqueue to put
+ *
+ * Drop a reference of @pwq.  If its refcnt reaches zero, schedule its
+ * destruction.  The caller should be holding the matching pool->lock.
+ */
+static void put_pwq(struct pool_workqueue *pwq)
+{
+	lockdep_assert_held(&pwq->pool->lock);
+	if (likely(--pwq->refcnt))
+		return;
+	if (WARN_ON_ONCE(!(pwq->wq->flags & WQ_UNBOUND)))
+		return;
+	/*
+	 * @pwq can't be released under pool->lock, bounce to
+	 * pwq_unbound_release_workfn().  This never recurses on the same
+	 * pool->lock as this path is taken only for unbound workqueues and
+	 * the release work item is scheduled on a per-cpu workqueue.  To
+	 * avoid lockdep warning, unbound pool->locks are given lockdep
+	 * subclass of 1 in get_unbound_pool().
+	 */
+	schedule_work(&pwq->unbound_release_work);
+}
+
+/**
+ * put_pwq_unlocked - put_pwq() with surrounding pool lock/unlock
+ * @pwq: pool_workqueue to put (can be %NULL)
+ *
+ * put_pwq() with locking.  This function also allows %NULL @pwq.
+ */
+static void put_pwq_unlocked(struct pool_workqueue *pwq)
+{
+	if (pwq) {
+		/*
+		 * As both pwqs and pools are RCU protected, the
+		 * following lock operations are safe.
+		 */
+		raw_spin_lock_irq(&pwq->pool->lock);
+		put_pwq(pwq);
+		raw_spin_unlock_irq(&pwq->pool->lock);
+	}
+}
+
+static void pwq_activate_inactive_work(struct work_struct *work)
+{
+	struct pool_workqueue *pwq = get_work_pwq(work);
+
+	trace_workqueue_activate_work(work);
+	if (list_empty(&pwq->pool->worklist))
+		pwq->pool->watchdog_ts = jiffies;
+	move_linked_works(work, &pwq->pool->worklist, NULL);
+	__clear_bit(WORK_STRUCT_INACTIVE_BIT, work_data_bits(work));
+	pwq->nr_active++;
+}
+
+static void pwq_activate_first_inactive(struct pool_workqueue *pwq)
+{
+	struct work_struct *work = list_first_entry(&pwq->inactive_works,
+						    struct work_struct, entry);
+
+	pwq_activate_inactive_work(work);
+}
+
+/**
+ * pwq_dec_nr_in_flight - decrement pwq's nr_in_flight
+ * @pwq: pwq of interest
+ * @work_data: work_data of work which left the queue
+ *
+ * A work either has completed or is removed from pending queue,
+ * decrement nr_in_flight of its pwq and handle workqueue flushing.
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(pool->lock).
+ */
+static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, unsigned long work_data)
+{
+	int color = get_work_color(work_data);
+
+	if (!(work_data & WORK_STRUCT_INACTIVE)) {
+		pwq->nr_active--;
+		if (!list_empty(&pwq->inactive_works)) {
+			/* one down, submit an inactive one */
+			if (pwq->nr_active < pwq->max_active)
+				pwq_activate_first_inactive(pwq);
+		}
+	}
+
+	pwq->nr_in_flight[color]--;
+
+	/* is flush in progress and are we at the flushing tip? */
+	if (likely(pwq->flush_color != color))
+		goto out_put;
+
+	/* are there still in-flight works? */
+	if (pwq->nr_in_flight[color])
+		goto out_put;
+
+	/* this pwq is done, clear flush_color */
+	pwq->flush_color = -1;
+
+	/*
+	 * If this was the last pwq, wake up the first flusher.  It
+	 * will handle the rest.
+	 */
+	if (atomic_dec_and_test(&pwq->wq->nr_pwqs_to_flush))
+		complete(&pwq->wq->first_flusher->done);
+out_put:
+	put_pwq(pwq);
+}
+
+/**
+ * try_to_grab_pending - steal work item from worklist and disable irq
+ * @work: work item to steal
+ * @is_dwork: @work is a delayed_work
+ * @flags: place to store irq state
+ *
+ * Try to grab PENDING bit of @work.  This function can handle @work in any
+ * stable state - idle, on timer or on worklist.
+ *
+ * Return:
+ *
+ *  ========	================================================================
+ *  1		if @work was pending and we successfully stole PENDING
+ *  0		if @work was idle and we claimed PENDING
+ *  -EAGAIN	if PENDING couldn't be grabbed at the moment, safe to busy-retry
+ *  -ENOENT	if someone else is canceling @work, this state may persist
+ *		for arbitrarily long
+ *  ========	================================================================
+ *
+ * Note:
+ * On >= 0 return, the caller owns @work's PENDING bit.  To avoid getting
+ * interrupted while holding PENDING and @work off queue, irq must be
+ * disabled on entry.  This, combined with delayed_work->timer being
+ * irqsafe, ensures that we return -EAGAIN for finite short period of time.
+ *
+ * On successful return, >= 0, irq is disabled and the caller is
+ * responsible for releasing it using local_irq_restore(*@flags).
+ *
+ * This function is safe to call from any context including IRQ handler.
+ */
+static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
+			       unsigned long *flags)
+{
+	struct worker_pool *pool;
+	struct pool_workqueue *pwq;
+
+	local_irq_save(*flags);
+
+	/* try to steal the timer if it exists */
+	if (is_dwork) {
+		struct delayed_work *dwork = to_delayed_work(work);
+
+		/*
+		 * dwork->timer is irqsafe.  If del_timer() fails, it's
+		 * guaranteed that the timer is not queued anywhere and not
+		 * running on the local CPU.
+		 */
+		if (likely(del_timer(&dwork->timer)))
+			return 1;
+	}
+
+	/* try to claim PENDING the normal way */
+	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
+		return 0;
+
+	rcu_read_lock();
+	/*
+	 * The queueing is in progress, or it is already queued. Try to
+	 * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
+	 */
+	pool = get_work_pool(work);
+	if (!pool)
+		goto fail;
+
+	raw_spin_lock(&pool->lock);
+	/*
+	 * work->data is guaranteed to point to pwq only while the work
+	 * item is queued on pwq->wq, and both updating work->data to point
+	 * to pwq on queueing and to pool on dequeueing are done under
+	 * pwq->pool->lock.  This in turn guarantees that, if work->data
+	 * points to pwq which is associated with a locked pool, the work
+	 * item is currently queued on that pool.
+	 */
+	pwq = get_work_pwq(work);
+	if (pwq && pwq->pool == pool) {
+		debug_work_deactivate(work);
+
+		/*
+		 * A cancelable inactive work item must be in the
+		 * pwq->inactive_works since a queued barrier can't be
+		 * canceled (see the comments in insert_wq_barrier()).
+		 *
+		 * An inactive work item cannot be grabbed directly because
+		 * it might have linked barrier work items which, if left
+		 * on the inactive_works list, will confuse pwq->nr_active
+		 * management later on and cause stall.  Make sure the work
+		 * item is activated before grabbing.
+		 */
+		if (*work_data_bits(work) & WORK_STRUCT_INACTIVE)
+			pwq_activate_inactive_work(work);
+
+		list_del_init(&work->entry);
+		pwq_dec_nr_in_flight(pwq, *work_data_bits(work));
+
+		/* work->data points to pwq iff queued, point to pool */
+		set_work_pool_and_keep_pending(work, pool->id);
+
+		raw_spin_unlock(&pool->lock);
+		rcu_read_unlock();
+		return 1;
+	}
+	raw_spin_unlock(&pool->lock);
+fail:
+	rcu_read_unlock();
+	local_irq_restore(*flags);
+	if (work_is_canceling(work))
+		return -ENOENT;
+	cpu_relax();
+	return -EAGAIN;
+}
+
+/**
+ * insert_work - insert a work into a pool
+ * @pwq: pwq @work belongs to
+ * @work: work to insert
+ * @head: insertion point
+ * @extra_flags: extra WORK_STRUCT_* flags to set
+ *
+ * Insert @work which belongs to @pwq after @head.  @extra_flags is or'd to
+ * work_struct flags.
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(pool->lock).
+ */
+static void insert_work(struct pool_workqueue *pwq, struct work_struct *work,
+			struct list_head *head, unsigned int extra_flags)
+{
+	struct worker_pool *pool = pwq->pool;
+
+	/* record the work call stack in order to print it in KASAN reports */
+	kasan_record_aux_stack_noalloc(work);
+
+	/* we own @work, set data and link */
+	set_work_pwq(work, pwq, extra_flags);
+	list_add_tail(&work->entry, head);
+	get_pwq(pwq);
+
+	if (__need_more_worker(pool))
+		wake_up_worker(pool);
+}
+
+/*
+ * Test whether @work is being queued from another work executing on the
+ * same workqueue.
+ */
+static bool is_chained_work(struct workqueue_struct *wq)
+{
+	struct worker *worker;
+
+	worker = current_wq_worker();
+	/*
+	 * Return %true iff I'm a worker executing a work item on @wq.  If
+	 * I'm @worker, it's safe to dereference it without locking.
+	 */
+	return worker && worker->current_pwq->wq == wq;
+}
+
+/*
+ * When queueing an unbound work item to a wq, prefer local CPU if allowed
+ * by wq_unbound_cpumask.  Otherwise, round robin among the allowed ones to
+ * avoid perturbing sensitive tasks.
+ */
+static int wq_select_unbound_cpu(int cpu)
+{
+	static bool printed_dbg_warning;
+	int new_cpu;
+
+	if (likely(!wq_debug_force_rr_cpu)) {
+		if (cpumask_test_cpu(cpu, wq_unbound_cpumask))
+			return cpu;
+	} else if (!printed_dbg_warning) {
+		pr_warn("workqueue: round-robin CPU selection forced, expect performance impact\n");
+		printed_dbg_warning = true;
+	}
+
+	if (cpumask_empty(wq_unbound_cpumask))
+		return cpu;
+
+	new_cpu = __this_cpu_read(wq_rr_cpu_last);
+	new_cpu = cpumask_next_and(new_cpu, wq_unbound_cpumask, cpu_online_mask);
+	if (unlikely(new_cpu >= nr_cpu_ids)) {
+		new_cpu = cpumask_first_and(wq_unbound_cpumask, cpu_online_mask);
+		if (unlikely(new_cpu >= nr_cpu_ids))
+			return cpu;
+	}
+	__this_cpu_write(wq_rr_cpu_last, new_cpu);
+
+	return new_cpu;
+}
+
+static void __queue_work(int cpu, struct workqueue_struct *wq,
+			 struct work_struct *work)
+{
+	struct pool_workqueue *pwq;
+	struct worker_pool *last_pool;
+	struct list_head *worklist;
+	unsigned int work_flags;
+	unsigned int req_cpu = cpu;
+
+	/*
+	 * While a work item is PENDING && off queue, a task trying to
+	 * steal the PENDING will busy-loop waiting for it to either get
+	 * queued or lose PENDING.  Grabbing PENDING and queueing should
+	 * happen with IRQ disabled.
+	 */
+	lockdep_assert_irqs_disabled();
+
+
+	/* if draining, only works from the same workqueue are allowed */
+	if (unlikely(wq->flags & __WQ_DRAINING) &&
+	    WARN_ON_ONCE(!is_chained_work(wq)))
+		return;
+	rcu_read_lock();
+retry:
+	/* pwq which will be used unless @work is executing elsewhere */
+	if (wq->flags & WQ_UNBOUND) {
+		if (req_cpu == WORK_CPU_UNBOUND)
+			cpu = wq_select_unbound_cpu(raw_smp_processor_id());
+		pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
+	} else {
+		if (req_cpu == WORK_CPU_UNBOUND)
+			cpu = raw_smp_processor_id();
+		pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
+	}
+
+	/*
+	 * If @work was previously on a different pool, it might still be
+	 * running there, in which case the work needs to be queued on that
+	 * pool to guarantee non-reentrancy.
+	 */
+	last_pool = get_work_pool(work);
+	if (last_pool && last_pool != pwq->pool) {
+		struct worker *worker;
+
+		raw_spin_lock(&last_pool->lock);
+
+		worker = find_worker_executing_work(last_pool, work);
+
+		if (worker && worker->current_pwq->wq == wq) {
+			pwq = worker->current_pwq;
+		} else {
+			/* meh... not running there, queue here */
+			raw_spin_unlock(&last_pool->lock);
+			raw_spin_lock(&pwq->pool->lock);
+		}
+	} else {
+		raw_spin_lock(&pwq->pool->lock);
+	}
+
+	/*
+	 * pwq is determined and locked.  For unbound pools, we could have
+	 * raced with pwq release and it could already be dead.  If its
+	 * refcnt is zero, repeat pwq selection.  Note that pwqs never die
+	 * without another pwq replacing it in the numa_pwq_tbl or while
+	 * work items are executing on it, so the retrying is guaranteed to
+	 * make forward-progress.
+	 */
+	if (unlikely(!pwq->refcnt)) {
+		if (wq->flags & WQ_UNBOUND) {
+			raw_spin_unlock(&pwq->pool->lock);
+			cpu_relax();
+			goto retry;
+		}
+		/* oops */
+		WARN_ONCE(true, "workqueue: per-cpu pwq for %s on cpu%d has 0 refcnt",
+			  wq->name, cpu);
+	}
+
+	/* pwq determined, queue */
+	trace_workqueue_queue_work(req_cpu, pwq, work);
+
+	if (WARN_ON(!list_empty(&work->entry)))
+		goto out;
+
+	pwq->nr_in_flight[pwq->work_color]++;
+	work_flags = work_color_to_flags(pwq->work_color);
+
+	if (likely(pwq->nr_active < pwq->max_active)) {
+		trace_workqueue_activate_work(work);
+		pwq->nr_active++;
+		worklist = &pwq->pool->worklist;
+		if (list_empty(worklist))
+			pwq->pool->watchdog_ts = jiffies;
+	} else {
+		work_flags |= WORK_STRUCT_INACTIVE;
+		worklist = &pwq->inactive_works;
+	}
+
+	debug_work_activate(work);
+	insert_work(pwq, work, worklist, work_flags);
+
+out:
+	raw_spin_unlock(&pwq->pool->lock);
+	rcu_read_unlock();
+}
+
+/**
+ * queue_work_on - queue work on specific cpu
+ * @cpu: CPU number to execute work on
+ * @wq: workqueue to use
+ * @work: work to queue
+ *
+ * We queue the work to a specific CPU, the caller must ensure it
+ * can't go away.  Callers that fail to ensure that the specified
+ * CPU cannot go away will execute on a randomly chosen CPU.
+ *
+ * Return: %false if @work was already on a queue, %true otherwise.
+ */
+bool queue_work_on(int cpu, struct workqueue_struct *wq,
+		   struct work_struct *work)
+{
+	bool ret = false;
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+		__queue_work(cpu, wq, work);
+		ret = true;
+	}
+
+	local_irq_restore(flags);
+	return ret;
+}
+EXPORT_SYMBOL(queue_work_on);
+
+/**
+ * workqueue_select_cpu_near - Select a CPU based on NUMA node
+ * @node: NUMA node ID that we want to select a CPU from
+ *
+ * This function will attempt to find a "random" cpu available on a given
+ * node. If there are no CPUs available on the given node it will return
+ * WORK_CPU_UNBOUND indicating that we should just schedule to any
+ * available CPU if we need to schedule this work.
+ */
+static int workqueue_select_cpu_near(int node)
+{
+	int cpu;
+
+	/* No point in doing this if NUMA isn't enabled for workqueues */
+	if (!wq_numa_enabled)
+		return WORK_CPU_UNBOUND;
+
+	/* Delay binding to CPU if node is not valid or online */
+	if (node < 0 || node >= MAX_NUMNODES || !node_online(node))
+		return WORK_CPU_UNBOUND;
+
+	/* Use local node/cpu if we are already there */
+	cpu = raw_smp_processor_id();
+	if (node == cpu_to_node(cpu))
+		return cpu;
+
+	/* Use "random" otherwise know as "first" online CPU of node */
+	cpu = cpumask_any_and(cpumask_of_node(node), cpu_online_mask);
+
+	/* If CPU is valid return that, otherwise just defer */
+	return cpu < nr_cpu_ids ? cpu : WORK_CPU_UNBOUND;
+}
+
+/**
+ * queue_work_node - queue work on a "random" cpu for a given NUMA node
+ * @node: NUMA node that we are targeting the work for
+ * @wq: workqueue to use
+ * @work: work to queue
+ *
+ * We queue the work to a "random" CPU within a given NUMA node. The basic
+ * idea here is to provide a way to somehow associate work with a given
+ * NUMA node.
+ *
+ * This function will only make a best effort attempt at getting this onto
+ * the right NUMA node. If no node is requested or the requested node is
+ * offline then we just fall back to standard queue_work behavior.
+ *
+ * Currently the "random" CPU ends up being the first available CPU in the
+ * intersection of cpu_online_mask and the cpumask of the node, unless we
+ * are running on the node. In that case we just use the current CPU.
+ *
+ * Return: %false if @work was already on a queue, %true otherwise.
+ */
+bool queue_work_node(int node, struct workqueue_struct *wq,
+		     struct work_struct *work)
+{
+	unsigned long flags;
+	bool ret = false;
+
+	/*
+	 * This current implementation is specific to unbound workqueues.
+	 * Specifically we only return the first available CPU for a given
+	 * node instead of cycling through individual CPUs within the node.
+	 *
+	 * If this is used with a per-cpu workqueue then the logic in
+	 * workqueue_select_cpu_near would need to be updated to allow for
+	 * some round robin type logic.
+	 */
+	WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND));
+
+	local_irq_save(flags);
+
+	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+		int cpu = workqueue_select_cpu_near(node);
+
+		__queue_work(cpu, wq, work);
+		ret = true;
+	}
+
+	local_irq_restore(flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(queue_work_node);
+
+void delayed_work_timer_fn(struct timer_list *t)
+{
+	struct delayed_work *dwork = from_timer(dwork, t, timer);
+
+	/* should have been called from irqsafe timer with irq already off */
+	__queue_work(dwork->cpu, dwork->wq, &dwork->work);
+}
+EXPORT_SYMBOL(delayed_work_timer_fn);
+
+static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
+				struct delayed_work *dwork, unsigned long delay)
+{
+	struct timer_list *timer = &dwork->timer;
+	struct work_struct *work = &dwork->work;
+
+	WARN_ON_ONCE(!wq);
+	WARN_ON_ONCE(timer->function != delayed_work_timer_fn);
+	WARN_ON_ONCE(timer_pending(timer));
+	WARN_ON_ONCE(!list_empty(&work->entry));
+
+	/*
+	 * If @delay is 0, queue @dwork->work immediately.  This is for
+	 * both optimization and correctness.  The earliest @timer can
+	 * expire is on the closest next tick and delayed_work users depend
+	 * on that there's no such delay when @delay is 0.
+	 */
+	if (!delay) {
+		__queue_work(cpu, wq, &dwork->work);
+		return;
+	}
+
+	dwork->wq = wq;
+	dwork->cpu = cpu;
+	timer->expires = jiffies + delay;
+
+	if (unlikely(cpu != WORK_CPU_UNBOUND))
+		add_timer_on(timer, cpu);
+	else
+		add_timer(timer);
+}
+
+/**
+ * queue_delayed_work_on - queue work on specific CPU after delay
+ * @cpu: CPU number to execute work on
+ * @wq: workqueue to use
+ * @dwork: work to queue
+ * @delay: number of jiffies to wait before queueing
+ *
+ * Return: %false if @work was already on a queue, %true otherwise.  If
+ * @delay is zero and @dwork is idle, it will be scheduled for immediate
+ * execution.
+ */
+bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
+			   struct delayed_work *dwork, unsigned long delay)
+{
+	struct work_struct *work = &dwork->work;
+	bool ret = false;
+	unsigned long flags;
+
+	/* read the comment in __queue_work() */
+	local_irq_save(flags);
+
+	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+		__queue_delayed_work(cpu, wq, dwork, delay);
+		ret = true;
+	}
+
+	local_irq_restore(flags);
+	return ret;
+}
+EXPORT_SYMBOL(queue_delayed_work_on);
+
+/**
+ * mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU
+ * @cpu: CPU number to execute work on
+ * @wq: workqueue to use
+ * @dwork: work to queue
+ * @delay: number of jiffies to wait before queueing
+ *
+ * If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise,
+ * modify @dwork's timer so that it expires after @delay.  If @delay is
+ * zero, @work is guaranteed to be scheduled immediately regardless of its
+ * current state.
+ *
+ * Return: %false if @dwork was idle and queued, %true if @dwork was
+ * pending and its timer was modified.
+ *
+ * This function is safe to call from any context including IRQ handler.
+ * See try_to_grab_pending() for details.
+ */
+bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
+			 struct delayed_work *dwork, unsigned long delay)
+{
+	unsigned long flags;
+	int ret;
+
+	do {
+		ret = try_to_grab_pending(&dwork->work, true, &flags);
+	} while (unlikely(ret == -EAGAIN));
+
+	if (likely(ret >= 0)) {
+		__queue_delayed_work(cpu, wq, dwork, delay);
+		local_irq_restore(flags);
+	}
+
+	/* -ENOENT from try_to_grab_pending() becomes %true */
+	return ret;
+}
+EXPORT_SYMBOL_GPL(mod_delayed_work_on);
+
+static void rcu_work_rcufn(struct rcu_head *rcu)
+{
+	struct rcu_work *rwork = container_of(rcu, struct rcu_work, rcu);
+
+	/* read the comment in __queue_work() */
+	local_irq_disable();
+	__queue_work(WORK_CPU_UNBOUND, rwork->wq, &rwork->work);
+	local_irq_enable();
+}
+
+/**
+ * queue_rcu_work - queue work after a RCU grace period
+ * @wq: workqueue to use
+ * @rwork: work to queue
+ *
+ * Return: %false if @rwork was already pending, %true otherwise.  Note
+ * that a full RCU grace period is guaranteed only after a %true return.
+ * While @rwork is guaranteed to be executed after a %false return, the
+ * execution may happen before a full RCU grace period has passed.
+ */
+bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork)
+{
+	struct work_struct *work = &rwork->work;
+
+	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+		rwork->wq = wq;
+		call_rcu(&rwork->rcu, rcu_work_rcufn);
+		return true;
+	}
+
+	return false;
+}
+EXPORT_SYMBOL(queue_rcu_work);
+
+/**
+ * worker_enter_idle - enter idle state
+ * @worker: worker which is entering idle state
+ *
+ * @worker is entering idle state.  Update stats and idle timer if
+ * necessary.
+ *
+ * LOCKING:
+ * raw_spin_lock_irq(pool->lock).
+ */
+static void worker_enter_idle(struct worker *worker)
+{
+	struct worker_pool *pool = worker->pool;
+
+	if (WARN_ON_ONCE(worker->flags & WORKER_IDLE) ||
+	    WARN_ON_ONCE(!list_empty(&worker->entry) &&
+			 (worker->hentry.next || worker->hentry.pprev)))
+		return;
+
+	/* can't use worker_set_flags(), also called from create_worker() */
+	worker->flags |= WORKER_IDLE;
+	pool->nr_idle++;
+	worker->last_active = jiffies;
+
+	/* idle_list is LIFO */
+	list_add(&worker->entry, &pool->idle_list);
+
+	if (too_many_workers(pool) && !timer_pending(&pool->idle_timer))
+		mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT);
+
+	/* Sanity check nr_running. */
+	WARN_ON_ONCE(pool->nr_workers == pool->nr_idle && pool->nr_running);
+}
+
+/**
+ * worker_leave_idle - leave idle state
+ * @worker: worker which is leaving idle state
+ *
+ * @worker is leaving idle state.  Update stats.
+ *
+ * LOCKING:
+ * raw_spin_lock_irq(pool->lock).
+ */
+static void worker_leave_idle(struct worker *worker)
+{
+	struct worker_pool *pool = worker->pool;
+
+	if (WARN_ON_ONCE(!(worker->flags & WORKER_IDLE)))
+		return;
+	worker_clr_flags(worker, WORKER_IDLE);
+	pool->nr_idle--;
+	list_del_init(&worker->entry);
+}
+
+static struct worker *alloc_worker(int node)
+{
+	struct worker *worker;
+
+	worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, node);
+	if (worker) {
+		INIT_LIST_HEAD(&worker->entry);
+		INIT_LIST_HEAD(&worker->scheduled);
+		INIT_LIST_HEAD(&worker->node);
+		/* on creation a worker is in !idle && prep state */
+		worker->flags = WORKER_PREP;
+	}
+	return worker;
+}
+
+/**
+ * worker_attach_to_pool() - attach a worker to a pool
+ * @worker: worker to be attached
+ * @pool: the target pool
+ *
+ * Attach @worker to @pool.  Once attached, the %WORKER_UNBOUND flag and
+ * cpu-binding of @worker are kept coordinated with the pool across
+ * cpu-[un]hotplugs.
+ */
+static void worker_attach_to_pool(struct worker *worker,
+				   struct worker_pool *pool)
+{
+	mutex_lock(&wq_pool_attach_mutex);
+
+	/*
+	 * The wq_pool_attach_mutex ensures %POOL_DISASSOCIATED remains
+	 * stable across this function.  See the comments above the flag
+	 * definition for details.
+	 */
+	if (pool->flags & POOL_DISASSOCIATED)
+		worker->flags |= WORKER_UNBOUND;
+	else
+		kthread_set_per_cpu(worker->task, pool->cpu);
+
+	if (worker->rescue_wq)
+		set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask);
+
+	list_add_tail(&worker->node, &pool->workers);
+	worker->pool = pool;
+
+	mutex_unlock(&wq_pool_attach_mutex);
+}
+
+/**
+ * worker_detach_from_pool() - detach a worker from its pool
+ * @worker: worker which is attached to its pool
+ *
+ * Undo the attaching which had been done in worker_attach_to_pool().  The
+ * caller worker shouldn't access to the pool after detached except it has
+ * other reference to the pool.
+ */
+static void worker_detach_from_pool(struct worker *worker)
+{
+	struct worker_pool *pool = worker->pool;
+	struct completion *detach_completion = NULL;
+
+	mutex_lock(&wq_pool_attach_mutex);
+
+	kthread_set_per_cpu(worker->task, -1);
+	list_del(&worker->node);
+	worker->pool = NULL;
+
+	if (list_empty(&pool->workers))
+		detach_completion = pool->detach_completion;
+	mutex_unlock(&wq_pool_attach_mutex);
+
+	/* clear leftover flags without pool->lock after it is detached */
+	worker->flags &= ~(WORKER_UNBOUND | WORKER_REBOUND);
+
+	if (detach_completion)
+		complete(detach_completion);
+}
+
+/**
+ * create_worker - create a new workqueue worker
+ * @pool: pool the new worker will belong to
+ *
+ * Create and start a new worker which is attached to @pool.
+ *
+ * CONTEXT:
+ * Might sleep.  Does GFP_KERNEL allocations.
+ *
+ * Return:
+ * Pointer to the newly created worker.
+ */
+static struct worker *create_worker(struct worker_pool *pool)
+{
+	struct worker *worker;
+	int id;
+	char id_buf[16];
+
+	/* ID is needed to determine kthread name */
+	id = ida_alloc(&pool->worker_ida, GFP_KERNEL);
+	if (id < 0)
+		return NULL;
+
+	worker = alloc_worker(pool->node);
+	if (!worker)
+		goto fail;
+
+	worker->id = id;
+
+	if (pool->cpu >= 0)
+		snprintf(id_buf, sizeof(id_buf), "%d:%d%s", pool->cpu, id,
+			 pool->attrs->nice < 0  ? "H" : "");
+	else
+		snprintf(id_buf, sizeof(id_buf), "u%d:%d", pool->id, id);
+
+	worker->task = kthread_create_on_node(worker_thread, worker, pool->node,
+					      "kworker/%s", id_buf);
+	if (IS_ERR(worker->task))
+		goto fail;
+
+	set_user_nice(worker->task, pool->attrs->nice);
+	kthread_bind_mask(worker->task, pool->attrs->cpumask);
+
+	/* successful, attach the worker to the pool */
+	worker_attach_to_pool(worker, pool);
+
+	/* start the newly created worker */
+	raw_spin_lock_irq(&pool->lock);
+	worker->pool->nr_workers++;
+	worker_enter_idle(worker);
+	wake_up_process(worker->task);
+	raw_spin_unlock_irq(&pool->lock);
+
+	return worker;
+
+fail:
+	ida_free(&pool->worker_ida, id);
+	kfree(worker);
+	return NULL;
+}
+
+/**
+ * destroy_worker - destroy a workqueue worker
+ * @worker: worker to be destroyed
+ *
+ * Destroy @worker and adjust @pool stats accordingly.  The worker should
+ * be idle.
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(pool->lock).
+ */
+static void destroy_worker(struct worker *worker)
+{
+	struct worker_pool *pool = worker->pool;
+
+	lockdep_assert_held(&pool->lock);
+
+	/* sanity check frenzy */
+	if (WARN_ON(worker->current_work) ||
+	    WARN_ON(!list_empty(&worker->scheduled)) ||
+	    WARN_ON(!(worker->flags & WORKER_IDLE)))
+		return;
+
+	pool->nr_workers--;
+	pool->nr_idle--;
+
+	list_del_init(&worker->entry);
+	worker->flags |= WORKER_DIE;
+	wake_up_process(worker->task);
+}
+
+static void idle_worker_timeout(struct timer_list *t)
+{
+	struct worker_pool *pool = from_timer(pool, t, idle_timer);
+
+	raw_spin_lock_irq(&pool->lock);
+
+	while (too_many_workers(pool)) {
+		struct worker *worker;
+		unsigned long expires;
+
+		/* idle_list is kept in LIFO order, check the last one */
+		worker = list_entry(pool->idle_list.prev, struct worker, entry);
+		expires = worker->last_active + IDLE_WORKER_TIMEOUT;
+
+		if (time_before(jiffies, expires)) {
+			mod_timer(&pool->idle_timer, expires);
+			break;
+		}
+
+		destroy_worker(worker);
+	}
+
+	raw_spin_unlock_irq(&pool->lock);
+}
+
+static void send_mayday(struct work_struct *work)
+{
+	struct pool_workqueue *pwq = get_work_pwq(work);
+	struct workqueue_struct *wq = pwq->wq;
+
+	lockdep_assert_held(&wq_mayday_lock);
+
+	if (!wq->rescuer)
+		return;
+
+	/* mayday mayday mayday */
+	if (list_empty(&pwq->mayday_node)) {
+		/*
+		 * If @pwq is for an unbound wq, its base ref may be put at
+		 * any time due to an attribute change.  Pin @pwq until the
+		 * rescuer is done with it.
+		 */
+		get_pwq(pwq);
+		list_add_tail(&pwq->mayday_node, &wq->maydays);
+		wake_up_process(wq->rescuer->task);
+	}
+}
+
+static void pool_mayday_timeout(struct timer_list *t)
+{
+	struct worker_pool *pool = from_timer(pool, t, mayday_timer);
+	struct work_struct *work;
+
+	raw_spin_lock_irq(&pool->lock);
+	raw_spin_lock(&wq_mayday_lock);		/* for wq->maydays */
+
+	if (need_to_create_worker(pool)) {
+		/*
+		 * We've been trying to create a new worker but
+		 * haven't been successful.  We might be hitting an
+		 * allocation deadlock.  Send distress signals to
+		 * rescuers.
+		 */
+		list_for_each_entry(work, &pool->worklist, entry)
+			send_mayday(work);
+	}
+
+	raw_spin_unlock(&wq_mayday_lock);
+	raw_spin_unlock_irq(&pool->lock);
+
+	mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL);
+}
+
+/**
+ * maybe_create_worker - create a new worker if necessary
+ * @pool: pool to create a new worker for
+ *
+ * Create a new worker for @pool if necessary.  @pool is guaranteed to
+ * have at least one idle worker on return from this function.  If
+ * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is
+ * sent to all rescuers with works scheduled on @pool to resolve
+ * possible allocation deadlock.
+ *
+ * On return, need_to_create_worker() is guaranteed to be %false and
+ * may_start_working() %true.
+ *
+ * LOCKING:
+ * raw_spin_lock_irq(pool->lock) which may be released and regrabbed
+ * multiple times.  Does GFP_KERNEL allocations.  Called only from
+ * manager.
+ */
+static void maybe_create_worker(struct worker_pool *pool)
+__releases(&pool->lock)
+__acquires(&pool->lock)
+{
+restart:
+	raw_spin_unlock_irq(&pool->lock);
+
+	/* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */
+	mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT);
+
+	while (true) {
+		if (create_worker(pool) || !need_to_create_worker(pool))
+			break;
+
+		schedule_timeout_interruptible(CREATE_COOLDOWN);
+
+		if (!need_to_create_worker(pool))
+			break;
+	}
+
+	del_timer_sync(&pool->mayday_timer);
+	raw_spin_lock_irq(&pool->lock);
+	/*
+	 * This is necessary even after a new worker was just successfully
+	 * created as @pool->lock was dropped and the new worker might have
+	 * already become busy.
+	 */
+	if (need_to_create_worker(pool))
+		goto restart;
+}
+
+/**
+ * manage_workers - manage worker pool
+ * @worker: self
+ *
+ * Assume the manager role and manage the worker pool @worker belongs
+ * to.  At any given time, there can be only zero or one manager per
+ * pool.  The exclusion is handled automatically by this function.
+ *
+ * The caller can safely start processing works on false return.  On
+ * true return, it's guaranteed that need_to_create_worker() is false
+ * and may_start_working() is true.
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(pool->lock) which may be released and regrabbed
+ * multiple times.  Does GFP_KERNEL allocations.
+ *
+ * Return:
+ * %false if the pool doesn't need management and the caller can safely
+ * start processing works, %true if management function was performed and
+ * the conditions that the caller verified before calling the function may
+ * no longer be true.
+ */
+static bool manage_workers(struct worker *worker)
+{
+	struct worker_pool *pool = worker->pool;
+
+	if (pool->flags & POOL_MANAGER_ACTIVE)
+		return false;
+
+	pool->flags |= POOL_MANAGER_ACTIVE;
+	pool->manager = worker;
+
+	maybe_create_worker(pool);
+
+	pool->manager = NULL;
+	pool->flags &= ~POOL_MANAGER_ACTIVE;
+	rcuwait_wake_up(&manager_wait);
+	return true;
+}
+
+/**
+ * process_one_work - process single work
+ * @worker: self
+ * @work: work to process
+ *
+ * Process @work.  This function contains all the logics necessary to
+ * process a single work including synchronization against and
+ * interaction with other workers on the same cpu, queueing and
+ * flushing.  As long as context requirement is met, any worker can
+ * call this function to process a work.
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(pool->lock) which is released and regrabbed.
+ */
+static void process_one_work(struct worker *worker, struct work_struct *work)
+__releases(&pool->lock)
+__acquires(&pool->lock)
+{
+	struct pool_workqueue *pwq = get_work_pwq(work);
+	struct worker_pool *pool = worker->pool;
+	bool cpu_intensive = pwq->wq->flags & WQ_CPU_INTENSIVE;
+	unsigned long work_data;
+	struct worker *collision;
+#ifdef CONFIG_LOCKDEP
+	/*
+	 * It is permissible to free the struct work_struct from
+	 * inside the function that is called from it, this we need to
+	 * take into account for lockdep too.  To avoid bogus "held
+	 * lock freed" warnings as well as problems when looking into
+	 * work->lockdep_map, make a copy and use that here.
+	 */
+	struct lockdep_map lockdep_map;
+
+	lockdep_copy_map(&lockdep_map, &work->lockdep_map);
+#endif
+	/* ensure we're on the correct CPU */
+	WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) &&
+		     raw_smp_processor_id() != pool->cpu);
+
+	/*
+	 * A single work shouldn't be executed concurrently by
+	 * multiple workers on a single cpu.  Check whether anyone is
+	 * already processing the work.  If so, defer the work to the
+	 * currently executing one.
+	 */
+	collision = find_worker_executing_work(pool, work);
+	if (unlikely(collision)) {
+		move_linked_works(work, &collision->scheduled, NULL);
+		return;
+	}
+
+	/* claim and dequeue */
+	debug_work_deactivate(work);
+	hash_add(pool->busy_hash, &worker->hentry, (unsigned long)work);
+	worker->current_work = work;
+	worker->current_func = work->func;
+	worker->current_pwq = pwq;
+	work_data = *work_data_bits(work);
+	worker->current_color = get_work_color(work_data);
+
+	/*
+	 * Record wq name for cmdline and debug reporting, may get
+	 * overridden through set_worker_desc().
+	 */
+	strscpy(worker->desc, pwq->wq->name, WORKER_DESC_LEN);
+
+	list_del_init(&work->entry);
+
+	/*
+	 * CPU intensive works don't participate in concurrency management.
+	 * They're the scheduler's responsibility.  This takes @worker out
+	 * of concurrency management and the next code block will chain
+	 * execution of the pending work items.
+	 */
+	if (unlikely(cpu_intensive))
+		worker_set_flags(worker, WORKER_CPU_INTENSIVE);
+
+	/*
+	 * Wake up another worker if necessary.  The condition is always
+	 * false for normal per-cpu workers since nr_running would always
+	 * be >= 1 at this point.  This is used to chain execution of the
+	 * pending work items for WORKER_NOT_RUNNING workers such as the
+	 * UNBOUND and CPU_INTENSIVE ones.
+	 */
+	if (need_more_worker(pool))
+		wake_up_worker(pool);
+
+	/*
+	 * Record the last pool and clear PENDING which should be the last
+	 * update to @work.  Also, do this inside @pool->lock so that
+	 * PENDING and queued state changes happen together while IRQ is
+	 * disabled.
+	 */
+	set_work_pool_and_clear_pending(work, pool->id);
+
+	raw_spin_unlock_irq(&pool->lock);
+
+	lock_map_acquire(&pwq->wq->lockdep_map);
+	lock_map_acquire(&lockdep_map);
+	/*
+	 * Strictly speaking we should mark the invariant state without holding
+	 * any locks, that is, before these two lock_map_acquire()'s.
+	 *
+	 * However, that would result in:
+	 *
+	 *   A(W1)
+	 *   WFC(C)
+	 *		A(W1)
+	 *		C(C)
+	 *
+	 * Which would create W1->C->W1 dependencies, even though there is no
+	 * actual deadlock possible. There are two solutions, using a
+	 * read-recursive acquire on the work(queue) 'locks', but this will then
+	 * hit the lockdep limitation on recursive locks, or simply discard
+	 * these locks.
+	 *
+	 * AFAICT there is no possible deadlock scenario between the
+	 * flush_work() and complete() primitives (except for single-threaded
+	 * workqueues), so hiding them isn't a problem.
+	 */
+	lockdep_invariant_state(true);
+	trace_workqueue_execute_start(work);
+	worker->current_func(work);
+	/*
+	 * While we must be careful to not use "work" after this, the trace
+	 * point will only record its address.
+	 */
+	trace_workqueue_execute_end(work, worker->current_func);
+	lock_map_release(&lockdep_map);
+	lock_map_release(&pwq->wq->lockdep_map);
+
+	if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
+		pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n"
+		       "     last function: %ps\n",
+		       current->comm, preempt_count(), task_pid_nr(current),
+		       worker->current_func);
+		debug_show_held_locks(current);
+		dump_stack();
+	}
+
+	/*
+	 * The following prevents a kworker from hogging CPU on !PREEMPTION
+	 * kernels, where a requeueing work item waiting for something to
+	 * happen could deadlock with stop_machine as such work item could
+	 * indefinitely requeue itself while all other CPUs are trapped in
+	 * stop_machine. At the same time, report a quiescent RCU state so
+	 * the same condition doesn't freeze RCU.
+	 */
+	cond_resched();
+
+	raw_spin_lock_irq(&pool->lock);
+
+	/* clear cpu intensive status */
+	if (unlikely(cpu_intensive))
+		worker_clr_flags(worker, WORKER_CPU_INTENSIVE);
+
+	/* tag the worker for identification in schedule() */
+	worker->last_func = worker->current_func;
+
+	/* we're done with it, release */
+	hash_del(&worker->hentry);
+	worker->current_work = NULL;
+	worker->current_func = NULL;
+	worker->current_pwq = NULL;
+	worker->current_color = INT_MAX;
+	pwq_dec_nr_in_flight(pwq, work_data);
+}
+
+/**
+ * process_scheduled_works - process scheduled works
+ * @worker: self
+ *
+ * Process all scheduled works.  Please note that the scheduled list
+ * may change while processing a work, so this function repeatedly
+ * fetches a work from the top and executes it.
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(pool->lock) which may be released and regrabbed
+ * multiple times.
+ */
+static void process_scheduled_works(struct worker *worker)
+{
+	while (!list_empty(&worker->scheduled)) {
+		struct work_struct *work = list_first_entry(&worker->scheduled,
+						struct work_struct, entry);
+		process_one_work(worker, work);
+	}
+}
+
+static void set_pf_worker(bool val)
+{
+	mutex_lock(&wq_pool_attach_mutex);
+	if (val)
+		current->flags |= PF_WQ_WORKER;
+	else
+		current->flags &= ~PF_WQ_WORKER;
+	mutex_unlock(&wq_pool_attach_mutex);
+}
+
+/**
+ * worker_thread - the worker thread function
+ * @__worker: self
+ *
+ * The worker thread function.  All workers belong to a worker_pool -
+ * either a per-cpu one or dynamic unbound one.  These workers process all
+ * work items regardless of their specific target workqueue.  The only
+ * exception is work items which belong to workqueues with a rescuer which
+ * will be explained in rescuer_thread().
+ *
+ * Return: 0
+ */
+static int worker_thread(void *__worker)
+{
+	struct worker *worker = __worker;
+	struct worker_pool *pool = worker->pool;
+
+	/* tell the scheduler that this is a workqueue worker */
+	set_pf_worker(true);
+woke_up:
+	raw_spin_lock_irq(&pool->lock);
+
+	/* am I supposed to die? */
+	if (unlikely(worker->flags & WORKER_DIE)) {
+		raw_spin_unlock_irq(&pool->lock);
+		WARN_ON_ONCE(!list_empty(&worker->entry));
+		set_pf_worker(false);
+
+		set_task_comm(worker->task, "kworker/dying");
+		ida_free(&pool->worker_ida, worker->id);
+		worker_detach_from_pool(worker);
+		kfree(worker);
+		return 0;
+	}
+
+	worker_leave_idle(worker);
+recheck:
+	/* no more worker necessary? */
+	if (!need_more_worker(pool))
+		goto sleep;
+
+	/* do we need to manage? */
+	if (unlikely(!may_start_working(pool)) && manage_workers(worker))
+		goto recheck;
+
+	/*
+	 * ->scheduled list can only be filled while a worker is
+	 * preparing to process a work or actually processing it.
+	 * Make sure nobody diddled with it while I was sleeping.
+	 */
+	WARN_ON_ONCE(!list_empty(&worker->scheduled));
+
+	/*
+	 * Finish PREP stage.  We're guaranteed to have at least one idle
+	 * worker or that someone else has already assumed the manager
+	 * role.  This is where @worker starts participating in concurrency
+	 * management if applicable and concurrency management is restored
+	 * after being rebound.  See rebind_workers() for details.
+	 */
+	worker_clr_flags(worker, WORKER_PREP | WORKER_REBOUND);
+
+	do {
+		struct work_struct *work =
+			list_first_entry(&pool->worklist,
+					 struct work_struct, entry);
+
+		pool->watchdog_ts = jiffies;
+
+		if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) {
+			/* optimization path, not strictly necessary */
+			process_one_work(worker, work);
+			if (unlikely(!list_empty(&worker->scheduled)))
+				process_scheduled_works(worker);
+		} else {
+			move_linked_works(work, &worker->scheduled, NULL);
+			process_scheduled_works(worker);
+		}
+	} while (keep_working(pool));
+
+	worker_set_flags(worker, WORKER_PREP);
+sleep:
+	/*
+	 * pool->lock is held and there's no work to process and no need to
+	 * manage, sleep.  Workers are woken up only while holding
+	 * pool->lock or from local cpu, so setting the current state
+	 * before releasing pool->lock is enough to prevent losing any
+	 * event.
+	 */
+	worker_enter_idle(worker);
+	__set_current_state(TASK_IDLE);
+	raw_spin_unlock_irq(&pool->lock);
+	schedule();
+	goto woke_up;
+}
+
+/**
+ * rescuer_thread - the rescuer thread function
+ * @__rescuer: self
+ *
+ * Workqueue rescuer thread function.  There's one rescuer for each
+ * workqueue which has WQ_MEM_RECLAIM set.
+ *
+ * Regular work processing on a pool may block trying to create a new
+ * worker which uses GFP_KERNEL allocation which has slight chance of
+ * developing into deadlock if some works currently on the same queue
+ * need to be processed to satisfy the GFP_KERNEL allocation.  This is
+ * the problem rescuer solves.
+ *
+ * When such condition is possible, the pool summons rescuers of all
+ * workqueues which have works queued on the pool and let them process
+ * those works so that forward progress can be guaranteed.
+ *
+ * This should happen rarely.
+ *
+ * Return: 0
+ */
+static int rescuer_thread(void *__rescuer)
+{
+	struct worker *rescuer = __rescuer;
+	struct workqueue_struct *wq = rescuer->rescue_wq;
+	struct list_head *scheduled = &rescuer->scheduled;
+	bool should_stop;
+
+	set_user_nice(current, RESCUER_NICE_LEVEL);
+
+	/*
+	 * Mark rescuer as worker too.  As WORKER_PREP is never cleared, it
+	 * doesn't participate in concurrency management.
+	 */
+	set_pf_worker(true);
+repeat:
+	set_current_state(TASK_IDLE);
+
+	/*
+	 * By the time the rescuer is requested to stop, the workqueue
+	 * shouldn't have any work pending, but @wq->maydays may still have
+	 * pwq(s) queued.  This can happen by non-rescuer workers consuming
+	 * all the work items before the rescuer got to them.  Go through
+	 * @wq->maydays processing before acting on should_stop so that the
+	 * list is always empty on exit.
+	 */
+	should_stop = kthread_should_stop();
+
+	/* see whether any pwq is asking for help */
+	raw_spin_lock_irq(&wq_mayday_lock);
+
+	while (!list_empty(&wq->maydays)) {
+		struct pool_workqueue *pwq = list_first_entry(&wq->maydays,
+					struct pool_workqueue, mayday_node);
+		struct worker_pool *pool = pwq->pool;
+		struct work_struct *work, *n;
+		bool first = true;
+
+		__set_current_state(TASK_RUNNING);
+		list_del_init(&pwq->mayday_node);
+
+		raw_spin_unlock_irq(&wq_mayday_lock);
+
+		worker_attach_to_pool(rescuer, pool);
+
+		raw_spin_lock_irq(&pool->lock);
+
+		/*
+		 * Slurp in all works issued via this workqueue and
+		 * process'em.
+		 */
+		WARN_ON_ONCE(!list_empty(scheduled));
+		list_for_each_entry_safe(work, n, &pool->worklist, entry) {
+			if (get_work_pwq(work) == pwq) {
+				if (first)
+					pool->watchdog_ts = jiffies;
+				move_linked_works(work, scheduled, &n);
+			}
+			first = false;
+		}
+
+		if (!list_empty(scheduled)) {
+			process_scheduled_works(rescuer);
+
+			/*
+			 * The above execution of rescued work items could
+			 * have created more to rescue through
+			 * pwq_activate_first_inactive() or chained
+			 * queueing.  Let's put @pwq back on mayday list so
+			 * that such back-to-back work items, which may be
+			 * being used to relieve memory pressure, don't
+			 * incur MAYDAY_INTERVAL delay inbetween.
+			 */
+			if (pwq->nr_active && need_to_create_worker(pool)) {
+				raw_spin_lock(&wq_mayday_lock);
+				/*
+				 * Queue iff we aren't racing destruction
+				 * and somebody else hasn't queued it already.
+				 */
+				if (wq->rescuer && list_empty(&pwq->mayday_node)) {
+					get_pwq(pwq);
+					list_add_tail(&pwq->mayday_node, &wq->maydays);
+				}
+				raw_spin_unlock(&wq_mayday_lock);
+			}
+		}
+
+		/*
+		 * Put the reference grabbed by send_mayday().  @pool won't
+		 * go away while we're still attached to it.
+		 */
+		put_pwq(pwq);
+
+		/*
+		 * Leave this pool.  If need_more_worker() is %true, notify a
+		 * regular worker; otherwise, we end up with 0 concurrency
+		 * and stalling the execution.
+		 */
+		if (need_more_worker(pool))
+			wake_up_worker(pool);
+
+		raw_spin_unlock_irq(&pool->lock);
+
+		worker_detach_from_pool(rescuer);
+
+		raw_spin_lock_irq(&wq_mayday_lock);
+	}
+
+	raw_spin_unlock_irq(&wq_mayday_lock);
+
+	if (should_stop) {
+		__set_current_state(TASK_RUNNING);
+		set_pf_worker(false);
+		return 0;
+	}
+
+	/* rescuers should never participate in concurrency management */
+	WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING));
+	schedule();
+	goto repeat;
+}
+
+/**
+ * check_flush_dependency - check for flush dependency sanity
+ * @target_wq: workqueue being flushed
+ * @target_work: work item being flushed (NULL for workqueue flushes)
+ *
+ * %current is trying to flush the whole @target_wq or @target_work on it.
+ * If @target_wq doesn't have %WQ_MEM_RECLAIM, verify that %current is not
+ * reclaiming memory or running on a workqueue which doesn't have
+ * %WQ_MEM_RECLAIM as that can break forward-progress guarantee leading to
+ * a deadlock.
+ */
+static void check_flush_dependency(struct workqueue_struct *target_wq,
+				   struct work_struct *target_work)
+{
+	work_func_t target_func = target_work ? target_work->func : NULL;
+	struct worker *worker;
+
+	if (target_wq->flags & WQ_MEM_RECLAIM)
+		return;
+
+	worker = current_wq_worker();
+
+	WARN_ONCE(current->flags & PF_MEMALLOC,
+		  "workqueue: PF_MEMALLOC task %d(%s) is flushing !WQ_MEM_RECLAIM %s:%ps",
+		  current->pid, current->comm, target_wq->name, target_func);
+	WARN_ONCE(worker && ((worker->current_pwq->wq->flags &
+			      (WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM),
+		  "workqueue: WQ_MEM_RECLAIM %s:%ps is flushing !WQ_MEM_RECLAIM %s:%ps",
+		  worker->current_pwq->wq->name, worker->current_func,
+		  target_wq->name, target_func);
+}
+
+struct wq_barrier {
+	struct work_struct	work;
+	struct completion	done;
+	struct task_struct	*task;	/* purely informational */
+};
+
+static void wq_barrier_func(struct work_struct *work)
+{
+	struct wq_barrier *barr = container_of(work, struct wq_barrier, work);
+	complete(&barr->done);
+}
+
+/**
+ * insert_wq_barrier - insert a barrier work
+ * @pwq: pwq to insert barrier into
+ * @barr: wq_barrier to insert
+ * @target: target work to attach @barr to
+ * @worker: worker currently executing @target, NULL if @target is not executing
+ *
+ * @barr is linked to @target such that @barr is completed only after
+ * @target finishes execution.  Please note that the ordering
+ * guarantee is observed only with respect to @target and on the local
+ * cpu.
+ *
+ * Currently, a queued barrier can't be canceled.  This is because
+ * try_to_grab_pending() can't determine whether the work to be
+ * grabbed is at the head of the queue and thus can't clear LINKED
+ * flag of the previous work while there must be a valid next work
+ * after a work with LINKED flag set.
+ *
+ * Note that when @worker is non-NULL, @target may be modified
+ * underneath us, so we can't reliably determine pwq from @target.
+ *
+ * CONTEXT:
+ * raw_spin_lock_irq(pool->lock).
+ */
+static void insert_wq_barrier(struct pool_workqueue *pwq,
+			      struct wq_barrier *barr,
+			      struct work_struct *target, struct worker *worker)
+{
+	unsigned int work_flags = 0;
+	unsigned int work_color;
+	struct list_head *head;
+
+	/*
+	 * debugobject calls are safe here even with pool->lock locked
+	 * as we know for sure that this will not trigger any of the
+	 * checks and call back into the fixup functions where we
+	 * might deadlock.
+	 */
+	INIT_WORK_ONSTACK(&barr->work, wq_barrier_func);
+	__set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work));
+
+	init_completion_map(&barr->done, &target->lockdep_map);
+
+	barr->task = current;
+
+	/* The barrier work item does not participate in pwq->nr_active. */
+	work_flags |= WORK_STRUCT_INACTIVE;
+
+	/*
+	 * If @target is currently being executed, schedule the
+	 * barrier to the worker; otherwise, put it after @target.
+	 */
+	if (worker) {
+		head = worker->scheduled.next;
+		work_color = worker->current_color;
+	} else {
+		unsigned long *bits = work_data_bits(target);
+
+		head = target->entry.next;
+		/* there can already be other linked works, inherit and set */
+		work_flags |= *bits & WORK_STRUCT_LINKED;
+		work_color = get_work_color(*bits);
+		__set_bit(WORK_STRUCT_LINKED_BIT, bits);
+	}
+
+	pwq->nr_in_flight[work_color]++;
+	work_flags |= work_color_to_flags(work_color);
+
+	debug_work_activate(&barr->work);
+	insert_work(pwq, &barr->work, head, work_flags);
+}
+
+/**
+ * flush_workqueue_prep_pwqs - prepare pwqs for workqueue flushing
+ * @wq: workqueue being flushed
+ * @flush_color: new flush color, < 0 for no-op
+ * @work_color: new work color, < 0 for no-op
+ *
+ * Prepare pwqs for workqueue flushing.
+ *
+ * If @flush_color is non-negative, flush_color on all pwqs should be
+ * -1.  If no pwq has in-flight commands at the specified color, all
+ * pwq->flush_color's stay at -1 and %false is returned.  If any pwq
+ * has in flight commands, its pwq->flush_color is set to
+ * @flush_color, @wq->nr_pwqs_to_flush is updated accordingly, pwq
+ * wakeup logic is armed and %true is returned.
+ *
+ * The caller should have initialized @wq->first_flusher prior to
+ * calling this function with non-negative @flush_color.  If
+ * @flush_color is negative, no flush color update is done and %false
+ * is returned.
+ *
+ * If @work_color is non-negative, all pwqs should have the same
+ * work_color which is previous to @work_color and all will be
+ * advanced to @work_color.
+ *
+ * CONTEXT:
+ * mutex_lock(wq->mutex).
+ *
+ * Return:
+ * %true if @flush_color >= 0 and there's something to flush.  %false
+ * otherwise.
+ */
+static bool flush_workqueue_prep_pwqs(struct workqueue_struct *wq,
+				      int flush_color, int work_color)
+{
+	bool wait = false;
+	struct pool_workqueue *pwq;
+
+	if (flush_color >= 0) {
+		WARN_ON_ONCE(atomic_read(&wq->nr_pwqs_to_flush));
+		atomic_set(&wq->nr_pwqs_to_flush, 1);
+	}
+
+	for_each_pwq(pwq, wq) {
+		struct worker_pool *pool = pwq->pool;
+
+		raw_spin_lock_irq(&pool->lock);
+
+		if (flush_color >= 0) {
+			WARN_ON_ONCE(pwq->flush_color != -1);
+
+			if (pwq->nr_in_flight[flush_color]) {
+				pwq->flush_color = flush_color;
+				atomic_inc(&wq->nr_pwqs_to_flush);
+				wait = true;
+			}
+		}
+
+		if (work_color >= 0) {
+			WARN_ON_ONCE(work_color != work_next_color(pwq->work_color));
+			pwq->work_color = work_color;
+		}
+
+		raw_spin_unlock_irq(&pool->lock);
+	}
+
+	if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_pwqs_to_flush))
+		complete(&wq->first_flusher->done);
+
+	return wait;
+}
+
+/**
+ * __flush_workqueue - ensure that any scheduled work has run to completion.
+ * @wq: workqueue to flush
+ *
+ * This function sleeps until all work items which were queued on entry
+ * have finished execution, but it is not livelocked by new incoming ones.
+ */
+void __flush_workqueue(struct workqueue_struct *wq)
+{
+	struct wq_flusher this_flusher = {
+		.list = LIST_HEAD_INIT(this_flusher.list),
+		.flush_color = -1,
+		.done = COMPLETION_INITIALIZER_ONSTACK_MAP(this_flusher.done, wq->lockdep_map),
+	};
+	int next_color;
+
+	if (WARN_ON(!wq_online))
+		return;
+
+	lock_map_acquire(&wq->lockdep_map);
+	lock_map_release(&wq->lockdep_map);
+
+	mutex_lock(&wq->mutex);
+
+	/*
+	 * Start-to-wait phase
+	 */
+	next_color = work_next_color(wq->work_color);
+
+	if (next_color != wq->flush_color) {
+		/*
+		 * Color space is not full.  The current work_color
+		 * becomes our flush_color and work_color is advanced
+		 * by one.
+		 */
+		WARN_ON_ONCE(!list_empty(&wq->flusher_overflow));
+		this_flusher.flush_color = wq->work_color;
+		wq->work_color = next_color;
+
+		if (!wq->first_flusher) {
+			/* no flush in progress, become the first flusher */
+			WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);
+
+			wq->first_flusher = &this_flusher;
+
+			if (!flush_workqueue_prep_pwqs(wq, wq->flush_color,
+						       wq->work_color)) {
+				/* nothing to flush, done */
+				wq->flush_color = next_color;
+				wq->first_flusher = NULL;
+				goto out_unlock;
+			}
+		} else {
+			/* wait in queue */
+			WARN_ON_ONCE(wq->flush_color == this_flusher.flush_color);
+			list_add_tail(&this_flusher.list, &wq->flusher_queue);
+			flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
+		}
+	} else {
+		/*
+		 * Oops, color space is full, wait on overflow queue.
+		 * The next flush completion will assign us
+		 * flush_color and transfer to flusher_queue.
+		 */
+		list_add_tail(&this_flusher.list, &wq->flusher_overflow);
+	}
+
+	check_flush_dependency(wq, NULL);
+
+	mutex_unlock(&wq->mutex);
+
+	wait_for_completion(&this_flusher.done);
+
+	/*
+	 * Wake-up-and-cascade phase
+	 *
+	 * First flushers are responsible for cascading flushes and
+	 * handling overflow.  Non-first flushers can simply return.
+	 */
+	if (READ_ONCE(wq->first_flusher) != &this_flusher)
+		return;
+
+	mutex_lock(&wq->mutex);
+
+	/* we might have raced, check again with mutex held */
+	if (wq->first_flusher != &this_flusher)
+		goto out_unlock;
+
+	WRITE_ONCE(wq->first_flusher, NULL);
+
+	WARN_ON_ONCE(!list_empty(&this_flusher.list));
+	WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);
+
+	while (true) {
+		struct wq_flusher *next, *tmp;
+
+		/* complete all the flushers sharing the current flush color */
+		list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) {
+			if (next->flush_color != wq->flush_color)
+				break;
+			list_del_init(&next->list);
+			complete(&next->done);
+		}
+
+		WARN_ON_ONCE(!list_empty(&wq->flusher_overflow) &&
+			     wq->flush_color != work_next_color(wq->work_color));
+
+		/* this flush_color is finished, advance by one */
+		wq->flush_color = work_next_color(wq->flush_color);
+
+		/* one color has been freed, handle overflow queue */
+		if (!list_empty(&wq->flusher_overflow)) {
+			/*
+			 * Assign the same color to all overflowed
+			 * flushers, advance work_color and append to
+			 * flusher_queue.  This is the start-to-wait
+			 * phase for these overflowed flushers.
+			 */
+			list_for_each_entry(tmp, &wq->flusher_overflow, list)
+				tmp->flush_color = wq->work_color;
+
+			wq->work_color = work_next_color(wq->work_color);
+
+			list_splice_tail_init(&wq->flusher_overflow,
+					      &wq->flusher_queue);
+			flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
+		}
+
+		if (list_empty(&wq->flusher_queue)) {
+			WARN_ON_ONCE(wq->flush_color != wq->work_color);
+			break;
+		}
+
+		/*
+		 * Need to flush more colors.  Make the next flusher
+		 * the new first flusher and arm pwqs.
+		 */
+		WARN_ON_ONCE(wq->flush_color == wq->work_color);
+		WARN_ON_ONCE(wq->flush_color != next->flush_color);
+
+		list_del_init(&next->list);
+		wq->first_flusher = next;
+
+		if (flush_workqueue_prep_pwqs(wq, wq->flush_color, -1))
+			break;
+
+		/*
+		 * Meh... this color is already done, clear first
+		 * flusher and repeat cascading.
+		 */
+		wq->first_flusher = NULL;
+	}
+
+out_unlock:
+	mutex_unlock(&wq->mutex);
+}
+EXPORT_SYMBOL(__flush_workqueue);
+
+/**
+ * drain_workqueue - drain a workqueue
+ * @wq: workqueue to drain
+ *
+ * Wait until the workqueue becomes empty.  While draining is in progress,
+ * only chain queueing is allowed.  IOW, only currently pending or running
+ * work items on @wq can queue further work items on it.  @wq is flushed
+ * repeatedly until it becomes empty.  The number of flushing is determined
+ * by the depth of chaining and should be relatively short.  Whine if it
+ * takes too long.
+ */
+void drain_workqueue(struct workqueue_struct *wq)
+{
+	unsigned int flush_cnt = 0;
+	struct pool_workqueue *pwq;
+
+	/*
+	 * __queue_work() needs to test whether there are drainers, is much
+	 * hotter than drain_workqueue() and already looks at @wq->flags.
+	 * Use __WQ_DRAINING so that queue doesn't have to check nr_drainers.
+	 */
+	mutex_lock(&wq->mutex);
+	if (!wq->nr_drainers++)
+		wq->flags |= __WQ_DRAINING;
+	mutex_unlock(&wq->mutex);
+reflush:
+	__flush_workqueue(wq);
+
+	mutex_lock(&wq->mutex);
+
+	for_each_pwq(pwq, wq) {
+		bool drained;
+
+		raw_spin_lock_irq(&pwq->pool->lock);
+		drained = !pwq->nr_active && list_empty(&pwq->inactive_works);
+		raw_spin_unlock_irq(&pwq->pool->lock);
+
+		if (drained)
+			continue;
+
+		if (++flush_cnt == 10 ||
+		    (flush_cnt % 100 == 0 && flush_cnt <= 1000))
+			pr_warn("workqueue %s: %s() isn't complete after %u tries\n",
+				wq->name, __func__, flush_cnt);
+
+		mutex_unlock(&wq->mutex);
+		goto reflush;
+	}
+
+	if (!--wq->nr_drainers)
+		wq->flags &= ~__WQ_DRAINING;
+	mutex_unlock(&wq->mutex);
+}
+EXPORT_SYMBOL_GPL(drain_workqueue);
+
+static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
+			     bool from_cancel)
+{
+	struct worker *worker = NULL;
+	struct worker_pool *pool;
+	struct pool_workqueue *pwq;
+
+	might_sleep();
+
+	rcu_read_lock();
+	pool = get_work_pool(work);
+	if (!pool) {
+		rcu_read_unlock();
+		return false;
+	}
+
+	raw_spin_lock_irq(&pool->lock);
+	/* see the comment in try_to_grab_pending() with the same code */
+	pwq = get_work_pwq(work);
+	if (pwq) {
+		if (unlikely(pwq->pool != pool))
+			goto already_gone;
+	} else {
+		worker = find_worker_executing_work(pool, work);
+		if (!worker)
+			goto already_gone;
+		pwq = worker->current_pwq;
+	}
+
+	check_flush_dependency(pwq->wq, work);
+
+	insert_wq_barrier(pwq, barr, work, worker);
+	raw_spin_unlock_irq(&pool->lock);
+
+	/*
+	 * Force a lock recursion deadlock when using flush_work() inside a
+	 * single-threaded or rescuer equipped workqueue.
+	 *
+	 * For single threaded workqueues the deadlock happens when the work
+	 * is after the work issuing the flush_work(). For rescuer equipped
+	 * workqueues the deadlock happens when the rescuer stalls, blocking
+	 * forward progress.
+	 */
+	if (!from_cancel &&
+	    (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer)) {
+		lock_map_acquire(&pwq->wq->lockdep_map);
+		lock_map_release(&pwq->wq->lockdep_map);
+	}
+	rcu_read_unlock();
+	return true;
+already_gone:
+	raw_spin_unlock_irq(&pool->lock);
+	rcu_read_unlock();
+	return false;
+}
+
+static bool __flush_work(struct work_struct *work, bool from_cancel)
+{
+	struct wq_barrier barr;
+
+	if (WARN_ON(!wq_online))
+		return false;
+
+	if (WARN_ON(!work->func))
+		return false;
+
+	lock_map_acquire(&work->lockdep_map);
+	lock_map_release(&work->lockdep_map);
+
+	if (start_flush_work(work, &barr, from_cancel)) {
+		wait_for_completion(&barr.done);
+		destroy_work_on_stack(&barr.work);
+		return true;
+	} else {
+		return false;
+	}
+}
+
+/**
+ * flush_work - wait for a work to finish executing the last queueing instance
+ * @work: the work to flush
+ *
+ * Wait until @work has finished execution.  @work is guaranteed to be idle
+ * on return if it hasn't been requeued since flush started.
+ *
+ * Return:
+ * %true if flush_work() waited for the work to finish execution,
+ * %false if it was already idle.
+ */
+bool flush_work(struct work_struct *work)
+{
+	return __flush_work(work, false);
+}
+EXPORT_SYMBOL_GPL(flush_work);
+
+struct cwt_wait {
+	wait_queue_entry_t		wait;
+	struct work_struct	*work;
+};
+
+static int cwt_wakefn(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
+{
+	struct cwt_wait *cwait = container_of(wait, struct cwt_wait, wait);
+
+	if (cwait->work != key)
+		return 0;
+	return autoremove_wake_function(wait, mode, sync, key);
+}
+
+static bool __cancel_work_timer(struct work_struct *work, bool is_dwork)
+{
+	static DECLARE_WAIT_QUEUE_HEAD(cancel_waitq);
+	unsigned long flags;
+	int ret;
+
+	do {
+		ret = try_to_grab_pending(work, is_dwork, &flags);
+		/*
+		 * If someone else is already canceling, wait for it to
+		 * finish.  flush_work() doesn't work for PREEMPT_NONE
+		 * because we may get scheduled between @work's completion
+		 * and the other canceling task resuming and clearing
+		 * CANCELING - flush_work() will return false immediately
+		 * as @work is no longer busy, try_to_grab_pending() will
+		 * return -ENOENT as @work is still being canceled and the
+		 * other canceling task won't be able to clear CANCELING as
+		 * we're hogging the CPU.
+		 *
+		 * Let's wait for completion using a waitqueue.  As this
+		 * may lead to the thundering herd problem, use a custom
+		 * wake function which matches @work along with exclusive
+		 * wait and wakeup.
+		 */
+		if (unlikely(ret == -ENOENT)) {
+			struct cwt_wait cwait;
+
+			init_wait(&cwait.wait);
+			cwait.wait.func = cwt_wakefn;
+			cwait.work = work;
+
+			prepare_to_wait_exclusive(&cancel_waitq, &cwait.wait,
+						  TASK_UNINTERRUPTIBLE);
+			if (work_is_canceling(work))
+				schedule();
+			finish_wait(&cancel_waitq, &cwait.wait);
+		}
+	} while (unlikely(ret < 0));
+
+	/* tell other tasks trying to grab @work to back off */
+	mark_work_canceling(work);
+	local_irq_restore(flags);
+
+	/*
+	 * This allows canceling during early boot.  We know that @work
+	 * isn't executing.
+	 */
+	if (wq_online)
+		__flush_work(work, true);
+
+	clear_work_data(work);
+
+	/*
+	 * Paired with prepare_to_wait() above so that either
+	 * waitqueue_active() is visible here or !work_is_canceling() is
+	 * visible there.
+	 */
+	smp_mb();
+	if (waitqueue_active(&cancel_waitq))
+		__wake_up(&cancel_waitq, TASK_NORMAL, 1, work);
+
+	return ret;
+}
+
+/**
+ * cancel_work_sync - cancel a work and wait for it to finish
+ * @work: the work to cancel
+ *
+ * Cancel @work and wait for its execution to finish.  This function
+ * can be used even if the work re-queues itself or migrates to
+ * another workqueue.  On return from this function, @work is
+ * guaranteed to be not pending or executing on any CPU.
+ *
+ * cancel_work_sync(&delayed_work->work) must not be used for
+ * delayed_work's.  Use cancel_delayed_work_sync() instead.
+ *
+ * The caller must ensure that the workqueue on which @work was last
+ * queued can't be destroyed before this function returns.
+ *
+ * Return:
+ * %true if @work was pending, %false otherwise.
+ */
+bool cancel_work_sync(struct work_struct *work)
+{
+	return __cancel_work_timer(work, false);
+}
+EXPORT_SYMBOL_GPL(cancel_work_sync);
+
+/**
+ * flush_delayed_work - wait for a dwork to finish executing the last queueing
+ * @dwork: the delayed work to flush
+ *
+ * Delayed timer is cancelled and the pending work is queued for
+ * immediate execution.  Like flush_work(), this function only
+ * considers the last queueing instance of @dwork.
+ *
+ * Return:
+ * %true if flush_work() waited for the work to finish execution,
+ * %false if it was already idle.
+ */
+bool flush_delayed_work(struct delayed_work *dwork)
+{
+	local_irq_disable();
+	if (del_timer_sync(&dwork->timer))
+		__queue_work(dwork->cpu, dwork->wq, &dwork->work);
+	local_irq_enable();
+	return flush_work(&dwork->work);
+}
+EXPORT_SYMBOL(flush_delayed_work);
+
+/**
+ * flush_rcu_work - wait for a rwork to finish executing the last queueing
+ * @rwork: the rcu work to flush
+ *
+ * Return:
+ * %true if flush_rcu_work() waited for the work to finish execution,
+ * %false if it was already idle.
+ */
+bool flush_rcu_work(struct rcu_work *rwork)
+{
+	if (test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&rwork->work))) {
+		rcu_barrier();
+		flush_work(&rwork->work);
+		return true;
+	} else {
+		return flush_work(&rwork->work);
+	}
+}
+EXPORT_SYMBOL(flush_rcu_work);
+
+static bool __cancel_work(struct work_struct *work, bool is_dwork)
+{
+	unsigned long flags;
+	int ret;
+
+	do {
+		ret = try_to_grab_pending(work, is_dwork, &flags);
+	} while (unlikely(ret == -EAGAIN));
+
+	if (unlikely(ret < 0))
+		return false;
+
+	set_work_pool_and_clear_pending(work, get_work_pool_id(work));
+	local_irq_restore(flags);
+	return ret;
+}
+
+/*
+ * See cancel_delayed_work()
+ */
+bool cancel_work(struct work_struct *work)
+{
+	return __cancel_work(work, false);
+}
+EXPORT_SYMBOL(cancel_work);
+
+/**
+ * cancel_delayed_work - cancel a delayed work
+ * @dwork: delayed_work to cancel
+ *
+ * Kill off a pending delayed_work.
+ *
+ * Return: %true if @dwork was pending and canceled; %false if it wasn't
+ * pending.
+ *
+ * Note:
+ * The work callback function may still be running on return, unless
+ * it returns %true and the work doesn't re-arm itself.  Explicitly flush or
+ * use cancel_delayed_work_sync() to wait on it.
+ *
+ * This function is safe to call from any context including IRQ handler.
+ */
+bool cancel_delayed_work(struct delayed_work *dwork)
+{
+	return __cancel_work(&dwork->work, true);
+}
+EXPORT_SYMBOL(cancel_delayed_work);
+
+/**
+ * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish
+ * @dwork: the delayed work cancel
+ *
+ * This is cancel_work_sync() for delayed works.
+ *
+ * Return:
+ * %true if @dwork was pending, %false otherwise.
+ */
+bool cancel_delayed_work_sync(struct delayed_work *dwork)
+{
+	return __cancel_work_timer(&dwork->work, true);
+}
+EXPORT_SYMBOL(cancel_delayed_work_sync);
+
+/**
+ * schedule_on_each_cpu - execute a function synchronously on each online CPU
+ * @func: the function to call
+ *
+ * schedule_on_each_cpu() executes @func on each online CPU using the
+ * system workqueue and blocks until all CPUs have completed.
+ * schedule_on_each_cpu() is very slow.
+ *
+ * Return:
+ * 0 on success, -errno on failure.
+ */
+int schedule_on_each_cpu(work_func_t func)
+{
+	int cpu;
+	struct work_struct __percpu *works;
+
+	works = alloc_percpu(struct work_struct);
+	if (!works)
+		return -ENOMEM;
+
+	cpus_read_lock();
+
+	for_each_online_cpu(cpu) {
+		struct work_struct *work = per_cpu_ptr(works, cpu);
+
+		INIT_WORK(work, func);
+		schedule_work_on(cpu, work);
+	}
+
+	for_each_online_cpu(cpu)
+		flush_work(per_cpu_ptr(works, cpu));
+
+	cpus_read_unlock();
+	free_percpu(works);
+	return 0;
+}
+
+/**
+ * execute_in_process_context - reliably execute the routine with user context
+ * @fn:		the function to execute
+ * @ew:		guaranteed storage for the execute work structure (must
+ *		be available when the work executes)
+ *
+ * Executes the function immediately if process context is available,
+ * otherwise schedules the function for delayed execution.
+ *
+ * Return:	0 - function was executed
+ *		1 - function was scheduled for execution
+ */
+int execute_in_process_context(work_func_t fn, struct execute_work *ew)
+{
+	if (!in_interrupt()) {
+		fn(&ew->work);
+		return 0;
+	}
+
+	INIT_WORK(&ew->work, fn);
+	schedule_work(&ew->work);
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(execute_in_process_context);
+
+/**
+ * free_workqueue_attrs - free a workqueue_attrs
+ * @attrs: workqueue_attrs to free
+ *
+ * Undo alloc_workqueue_attrs().
+ */
+void free_workqueue_attrs(struct workqueue_attrs *attrs)
+{
+	if (attrs) {
+		free_cpumask_var(attrs->cpumask);
+		kfree(attrs);
+	}
+}
+
+/**
+ * alloc_workqueue_attrs - allocate a workqueue_attrs
+ *
+ * Allocate a new workqueue_attrs, initialize with default settings and
+ * return it.
+ *
+ * Return: The allocated new workqueue_attr on success. %NULL on failure.
+ */
+struct workqueue_attrs *alloc_workqueue_attrs(void)
+{
+	struct workqueue_attrs *attrs;
+
+	attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
+	if (!attrs)
+		goto fail;
+	if (!alloc_cpumask_var(&attrs->cpumask, GFP_KERNEL))
+		goto fail;
+
+	cpumask_copy(attrs->cpumask, cpu_possible_mask);
+	return attrs;
+fail:
+	free_workqueue_attrs(attrs);
+	return NULL;
+}
+
+static void copy_workqueue_attrs(struct workqueue_attrs *to,
+				 const struct workqueue_attrs *from)
+{
+	to->nice = from->nice;
+	cpumask_copy(to->cpumask, from->cpumask);
+	/*
+	 * Unlike hash and equality test, this function doesn't ignore
+	 * ->no_numa as it is used for both pool and wq attrs.  Instead,
+	 * get_unbound_pool() explicitly clears ->no_numa after copying.
+	 */
+	to->no_numa = from->no_numa;
+}
+
+/* hash value of the content of @attr */
+static u32 wqattrs_hash(const struct workqueue_attrs *attrs)
+{
+	u32 hash = 0;
+
+	hash = jhash_1word(attrs->nice, hash);
+	hash = jhash(cpumask_bits(attrs->cpumask),
+		     BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash);
+	return hash;
+}
+
+/* content equality test */
+static bool wqattrs_equal(const struct workqueue_attrs *a,
+			  const struct workqueue_attrs *b)
+{
+	if (a->nice != b->nice)
+		return false;
+	if (!cpumask_equal(a->cpumask, b->cpumask))
+		return false;
+	return true;
+}
+
+/**
+ * init_worker_pool - initialize a newly zalloc'd worker_pool
+ * @pool: worker_pool to initialize
+ *
+ * Initialize a newly zalloc'd @pool.  It also allocates @pool->attrs.
+ *
+ * Return: 0 on success, -errno on failure.  Even on failure, all fields
+ * inside @pool proper are initialized and put_unbound_pool() can be called
+ * on @pool safely to release it.
+ */
+static int init_worker_pool(struct worker_pool *pool)
+{
+	raw_spin_lock_init(&pool->lock);
+	pool->id = -1;
+	pool->cpu = -1;
+	pool->node = NUMA_NO_NODE;
+	pool->flags |= POOL_DISASSOCIATED;
+	pool->watchdog_ts = jiffies;
+	INIT_LIST_HEAD(&pool->worklist);
+	INIT_LIST_HEAD(&pool->idle_list);
+	hash_init(pool->busy_hash);
+
+	timer_setup(&pool->idle_timer, idle_worker_timeout, TIMER_DEFERRABLE);
+
+	timer_setup(&pool->mayday_timer, pool_mayday_timeout, 0);
+
+	INIT_LIST_HEAD(&pool->workers);
+
+	ida_init(&pool->worker_ida);
+	INIT_HLIST_NODE(&pool->hash_node);
+	pool->refcnt = 1;
+
+	/* shouldn't fail above this point */
+	pool->attrs = alloc_workqueue_attrs();
+	if (!pool->attrs)
+		return -ENOMEM;
+	return 0;
+}
+
+#ifdef CONFIG_LOCKDEP
+static void wq_init_lockdep(struct workqueue_struct *wq)
+{
+	char *lock_name;
+
+	lockdep_register_key(&wq->key);
+	lock_name = kasprintf(GFP_KERNEL, "%s%s", "(wq_completion)", wq->name);
+	if (!lock_name)
+		lock_name = wq->name;
+
+	wq->lock_name = lock_name;
+	lockdep_init_map(&wq->lockdep_map, lock_name, &wq->key, 0);
+}
+
+static void wq_unregister_lockdep(struct workqueue_struct *wq)
+{
+	lockdep_unregister_key(&wq->key);
+}
+
+static void wq_free_lockdep(struct workqueue_struct *wq)
+{
+	if (wq->lock_name != wq->name)
+		kfree(wq->lock_name);
+}
+#else
+static void wq_init_lockdep(struct workqueue_struct *wq)
+{
+}
+
+static void wq_unregister_lockdep(struct workqueue_struct *wq)
+{
+}
+
+static void wq_free_lockdep(struct workqueue_struct *wq)
+{
+}
+#endif
+
+static void rcu_free_wq(struct rcu_head *rcu)
+{
+	struct workqueue_struct *wq =
+		container_of(rcu, struct workqueue_struct, rcu);
+
+	wq_free_lockdep(wq);
+
+	if (!(wq->flags & WQ_UNBOUND))
+		free_percpu(wq->cpu_pwqs);
+	else
+		free_workqueue_attrs(wq->unbound_attrs);
+
+	kfree(wq);
+}
+
+static void rcu_free_pool(struct rcu_head *rcu)
+{
+	struct worker_pool *pool = container_of(rcu, struct worker_pool, rcu);
+
+	ida_destroy(&pool->worker_ida);
+	free_workqueue_attrs(pool->attrs);
+	kfree(pool);
+}
+
+/* This returns with the lock held on success (pool manager is inactive). */
+static bool wq_manager_inactive(struct worker_pool *pool)
+{
+	raw_spin_lock_irq(&pool->lock);
+
+	if (pool->flags & POOL_MANAGER_ACTIVE) {
+		raw_spin_unlock_irq(&pool->lock);
+		return false;
+	}
+	return true;
+}
+
+/**
+ * put_unbound_pool - put a worker_pool
+ * @pool: worker_pool to put
+ *
+ * Put @pool.  If its refcnt reaches zero, it gets destroyed in RCU
+ * safe manner.  get_unbound_pool() calls this function on its failure path
+ * and this function should be able to release pools which went through,
+ * successfully or not, init_worker_pool().
+ *
+ * Should be called with wq_pool_mutex held.
+ */
+static void put_unbound_pool(struct worker_pool *pool)
+{
+	DECLARE_COMPLETION_ONSTACK(detach_completion);
+	struct worker *worker;
+
+	lockdep_assert_held(&wq_pool_mutex);
+
+	if (--pool->refcnt)
+		return;
+
+	/* sanity checks */
+	if (WARN_ON(!(pool->cpu < 0)) ||
+	    WARN_ON(!list_empty(&pool->worklist)))
+		return;
+
+	/* release id and unhash */
+	if (pool->id >= 0)
+		idr_remove(&worker_pool_idr, pool->id);
+	hash_del(&pool->hash_node);
+
+	/*
+	 * Become the manager and destroy all workers.  This prevents
+	 * @pool's workers from blocking on attach_mutex.  We're the last
+	 * manager and @pool gets freed with the flag set.
+	 * Because of how wq_manager_inactive() works, we will hold the
+	 * spinlock after a successful wait.
+	 */
+	rcuwait_wait_event(&manager_wait, wq_manager_inactive(pool),
+			   TASK_UNINTERRUPTIBLE);
+	pool->flags |= POOL_MANAGER_ACTIVE;
+
+	while ((worker = first_idle_worker(pool)))
+		destroy_worker(worker);
+	WARN_ON(pool->nr_workers || pool->nr_idle);
+	raw_spin_unlock_irq(&pool->lock);
+
+	mutex_lock(&wq_pool_attach_mutex);
+	if (!list_empty(&pool->workers))
+		pool->detach_completion = &detach_completion;
+	mutex_unlock(&wq_pool_attach_mutex);
+
+	if (pool->detach_completion)
+		wait_for_completion(pool->detach_completion);
+
+	/* shut down the timers */
+	del_timer_sync(&pool->idle_timer);
+	del_timer_sync(&pool->mayday_timer);
+
+	/* RCU protected to allow dereferences from get_work_pool() */
+	call_rcu(&pool->rcu, rcu_free_pool);
+}
+
+/**
+ * get_unbound_pool - get a worker_pool with the specified attributes
+ * @attrs: the attributes of the worker_pool to get
+ *
+ * Obtain a worker_pool which has the same attributes as @attrs, bump the
+ * reference count and return it.  If there already is a matching
+ * worker_pool, it will be used; otherwise, this function attempts to
+ * create a new one.
+ *
+ * Should be called with wq_pool_mutex held.
+ *
+ * Return: On success, a worker_pool with the same attributes as @attrs.
+ * On failure, %NULL.
+ */
+static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
+{
+	u32 hash = wqattrs_hash(attrs);
+	struct worker_pool *pool;
+	int node;
+	int target_node = NUMA_NO_NODE;
+
+	lockdep_assert_held(&wq_pool_mutex);
+
+	/* do we already have a matching pool? */
+	hash_for_each_possible(unbound_pool_hash, pool, hash_node, hash) {
+		if (wqattrs_equal(pool->attrs, attrs)) {
+			pool->refcnt++;
+			return pool;
+		}
+	}
+
+	/* if cpumask is contained inside a NUMA node, we belong to that node */
+	if (wq_numa_enabled) {
+		for_each_node(node) {
+			if (cpumask_subset(attrs->cpumask,
+					   wq_numa_possible_cpumask[node])) {
+				target_node = node;
+				break;
+			}
+		}
+	}
+
+	/* nope, create a new one */
+	pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, target_node);
+	if (!pool || init_worker_pool(pool) < 0)
+		goto fail;
+
+	lockdep_set_subclass(&pool->lock, 1);	/* see put_pwq() */
+	copy_workqueue_attrs(pool->attrs, attrs);
+	pool->node = target_node;
+
+	/*
+	 * no_numa isn't a worker_pool attribute, always clear it.  See
+	 * 'struct workqueue_attrs' comments for detail.
+	 */
+	pool->attrs->no_numa = false;
+
+	if (worker_pool_assign_id(pool) < 0)
+		goto fail;
+
+	/* create and start the initial worker */
+	if (wq_online && !create_worker(pool))
+		goto fail;
+
+	/* install */
+	hash_add(unbound_pool_hash, &pool->hash_node, hash);
+
+	return pool;
+fail:
+	if (pool)
+		put_unbound_pool(pool);
+	return NULL;
+}
+
+static void rcu_free_pwq(struct rcu_head *rcu)
+{
+	kmem_cache_free(pwq_cache,
+			container_of(rcu, struct pool_workqueue, rcu));
+}
+
+/*
+ * Scheduled on system_wq by put_pwq() when an unbound pwq hits zero refcnt
+ * and needs to be destroyed.
+ */
+static void pwq_unbound_release_workfn(struct work_struct *work)
+{
+	struct pool_workqueue *pwq = container_of(work, struct pool_workqueue,
+						  unbound_release_work);
+	struct workqueue_struct *wq = pwq->wq;
+	struct worker_pool *pool = pwq->pool;
+	bool is_last = false;
+
+	/*
+	 * when @pwq is not linked, it doesn't hold any reference to the
+	 * @wq, and @wq is invalid to access.
+	 */
+	if (!list_empty(&pwq->pwqs_node)) {
+		if (WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND)))
+			return;
+
+		mutex_lock(&wq->mutex);
+		list_del_rcu(&pwq->pwqs_node);
+		is_last = list_empty(&wq->pwqs);
+		mutex_unlock(&wq->mutex);
+	}
+
+	mutex_lock(&wq_pool_mutex);
+	put_unbound_pool(pool);
+	mutex_unlock(&wq_pool_mutex);
+
+	call_rcu(&pwq->rcu, rcu_free_pwq);
+
+	/*
+	 * If we're the last pwq going away, @wq is already dead and no one
+	 * is gonna access it anymore.  Schedule RCU free.
+	 */
+	if (is_last) {
+		wq_unregister_lockdep(wq);
+		call_rcu(&wq->rcu, rcu_free_wq);
+	}
+}
+
+/**
+ * pwq_adjust_max_active - update a pwq's max_active to the current setting
+ * @pwq: target pool_workqueue
+ *
+ * If @pwq isn't freezing, set @pwq->max_active to the associated
+ * workqueue's saved_max_active and activate inactive work items
+ * accordingly.  If @pwq is freezing, clear @pwq->max_active to zero.
+ */
+static void pwq_adjust_max_active(struct pool_workqueue *pwq)
+{
+	struct workqueue_struct *wq = pwq->wq;
+	bool freezable = wq->flags & WQ_FREEZABLE;
+	unsigned long flags;
+
+	/* for @wq->saved_max_active */
+	lockdep_assert_held(&wq->mutex);
+
+	/* fast exit for non-freezable wqs */
+	if (!freezable && pwq->max_active == wq->saved_max_active)
+		return;
+
+	/* this function can be called during early boot w/ irq disabled */
+	raw_spin_lock_irqsave(&pwq->pool->lock, flags);
+
+	/*
+	 * During [un]freezing, the caller is responsible for ensuring that
+	 * this function is called at least once after @workqueue_freezing
+	 * is updated and visible.
+	 */
+	if (!freezable || !workqueue_freezing) {
+		bool kick = false;
+
+		pwq->max_active = wq->saved_max_active;
+
+		while (!list_empty(&pwq->inactive_works) &&
+		       pwq->nr_active < pwq->max_active) {
+			pwq_activate_first_inactive(pwq);
+			kick = true;
+		}
+
+		/*
+		 * Need to kick a worker after thawed or an unbound wq's
+		 * max_active is bumped. In realtime scenarios, always kicking a
+		 * worker will cause interference on the isolated cpu cores, so
+		 * let's kick iff work items were activated.
+		 */
+		if (kick)
+			wake_up_worker(pwq->pool);
+	} else {
+		pwq->max_active = 0;
+	}
+
+	raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
+}
+
+/* initialize newly allocated @pwq which is associated with @wq and @pool */
+static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq,
+		     struct worker_pool *pool)
+{
+	BUG_ON((unsigned long)pwq & WORK_STRUCT_FLAG_MASK);
+
+	memset(pwq, 0, sizeof(*pwq));
+
+	pwq->pool = pool;
+	pwq->wq = wq;
+	pwq->flush_color = -1;
+	pwq->refcnt = 1;
+	INIT_LIST_HEAD(&pwq->inactive_works);
+	INIT_LIST_HEAD(&pwq->pwqs_node);
+	INIT_LIST_HEAD(&pwq->mayday_node);
+	INIT_WORK(&pwq->unbound_release_work, pwq_unbound_release_workfn);
+}
+
+/* sync @pwq with the current state of its associated wq and link it */
+static void link_pwq(struct pool_workqueue *pwq)
+{
+	struct workqueue_struct *wq = pwq->wq;
+
+	lockdep_assert_held(&wq->mutex);
+
+	/* may be called multiple times, ignore if already linked */
+	if (!list_empty(&pwq->pwqs_node))
+		return;
+
+	/* set the matching work_color */
+	pwq->work_color = wq->work_color;
+
+	/* sync max_active to the current setting */
+	pwq_adjust_max_active(pwq);
+
+	/* link in @pwq */
+	list_add_rcu(&pwq->pwqs_node, &wq->pwqs);
+}
+
+/* obtain a pool matching @attr and create a pwq associating the pool and @wq */
+static struct pool_workqueue *alloc_unbound_pwq(struct workqueue_struct *wq,
+					const struct workqueue_attrs *attrs)
+{
+	struct worker_pool *pool;
+	struct pool_workqueue *pwq;
+
+	lockdep_assert_held(&wq_pool_mutex);
+
+	pool = get_unbound_pool(attrs);
+	if (!pool)
+		return NULL;
+
+	pwq = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, pool->node);
+	if (!pwq) {
+		put_unbound_pool(pool);
+		return NULL;
+	}
+
+	init_pwq(pwq, wq, pool);
+	return pwq;
+}
+
+/**
+ * wq_calc_node_cpumask - calculate a wq_attrs' cpumask for the specified node
+ * @attrs: the wq_attrs of the default pwq of the target workqueue
+ * @node: the target NUMA node
+ * @cpu_going_down: if >= 0, the CPU to consider as offline
+ * @cpumask: outarg, the resulting cpumask
+ *
+ * Calculate the cpumask a workqueue with @attrs should use on @node.  If
+ * @cpu_going_down is >= 0, that cpu is considered offline during
+ * calculation.  The result is stored in @cpumask.
+ *
+ * If NUMA affinity is not enabled, @attrs->cpumask is always used.  If
+ * enabled and @node has online CPUs requested by @attrs, the returned
+ * cpumask is the intersection of the possible CPUs of @node and
+ * @attrs->cpumask.
+ *
+ * The caller is responsible for ensuring that the cpumask of @node stays
+ * stable.
+ *
+ * Return: %true if the resulting @cpumask is different from @attrs->cpumask,
+ * %false if equal.
+ */
+static bool wq_calc_node_cpumask(const struct workqueue_attrs *attrs, int node,
+				 int cpu_going_down, cpumask_t *cpumask)
+{
+	if (!wq_numa_enabled || attrs->no_numa)
+		goto use_dfl;
+
+	/* does @node have any online CPUs @attrs wants? */
+	cpumask_and(cpumask, cpumask_of_node(node), attrs->cpumask);
+	if (cpu_going_down >= 0)
+		cpumask_clear_cpu(cpu_going_down, cpumask);
+
+	if (cpumask_empty(cpumask))
+		goto use_dfl;
+
+	/* yeap, return possible CPUs in @node that @attrs wants */
+	cpumask_and(cpumask, attrs->cpumask, wq_numa_possible_cpumask[node]);
+
+	if (cpumask_empty(cpumask)) {
+		pr_warn_once("WARNING: workqueue cpumask: online intersect > "
+				"possible intersect\n");
+		return false;
+	}
+
+	return !cpumask_equal(cpumask, attrs->cpumask);
+
+use_dfl:
+	cpumask_copy(cpumask, attrs->cpumask);
+	return false;
+}
+
+/* install @pwq into @wq's numa_pwq_tbl[] for @node and return the old pwq */
+static struct pool_workqueue *numa_pwq_tbl_install(struct workqueue_struct *wq,
+						   int node,
+						   struct pool_workqueue *pwq)
+{
+	struct pool_workqueue *old_pwq;
+
+	lockdep_assert_held(&wq_pool_mutex);
+	lockdep_assert_held(&wq->mutex);
+
+	/* link_pwq() can handle duplicate calls */
+	link_pwq(pwq);
+
+	old_pwq = rcu_access_pointer(wq->numa_pwq_tbl[node]);
+	rcu_assign_pointer(wq->numa_pwq_tbl[node], pwq);
+	return old_pwq;
+}
+
+/* context to store the prepared attrs & pwqs before applying */
+struct apply_wqattrs_ctx {
+	struct workqueue_struct	*wq;		/* target workqueue */
+	struct workqueue_attrs	*attrs;		/* attrs to apply */
+	struct list_head	list;		/* queued for batching commit */
+	struct pool_workqueue	*dfl_pwq;
+	struct pool_workqueue	*pwq_tbl[];
+};
+
+/* free the resources after success or abort */
+static void apply_wqattrs_cleanup(struct apply_wqattrs_ctx *ctx)
+{
+	if (ctx) {
+		int node;
+
+		for_each_node(node)
+			put_pwq_unlocked(ctx->pwq_tbl[node]);
+		put_pwq_unlocked(ctx->dfl_pwq);
+
+		free_workqueue_attrs(ctx->attrs);
+
+		kfree(ctx);
+	}
+}
+
+/* allocate the attrs and pwqs for later installation */
+static struct apply_wqattrs_ctx *
+apply_wqattrs_prepare(struct workqueue_struct *wq,
+		      const struct workqueue_attrs *attrs,
+		      const cpumask_var_t unbound_cpumask)
+{
+	struct apply_wqattrs_ctx *ctx;
+	struct workqueue_attrs *new_attrs, *tmp_attrs;
+	int node;
+
+	lockdep_assert_held(&wq_pool_mutex);
+
+	ctx = kzalloc(struct_size(ctx, pwq_tbl, nr_node_ids), GFP_KERNEL);
+
+	new_attrs = alloc_workqueue_attrs();
+	tmp_attrs = alloc_workqueue_attrs();
+	if (!ctx || !new_attrs || !tmp_attrs)
+		goto out_free;
+
+	/*
+	 * Calculate the attrs of the default pwq with unbound_cpumask
+	 * which is wq_unbound_cpumask or to set to wq_unbound_cpumask.
+	 * If the user configured cpumask doesn't overlap with the
+	 * wq_unbound_cpumask, we fallback to the wq_unbound_cpumask.
+	 */
+	copy_workqueue_attrs(new_attrs, attrs);
+	cpumask_and(new_attrs->cpumask, new_attrs->cpumask, unbound_cpumask);
+	if (unlikely(cpumask_empty(new_attrs->cpumask)))
+		cpumask_copy(new_attrs->cpumask, unbound_cpumask);
+
+	/*
+	 * We may create multiple pwqs with differing cpumasks.  Make a
+	 * copy of @new_attrs which will be modified and used to obtain
+	 * pools.
+	 */
+	copy_workqueue_attrs(tmp_attrs, new_attrs);
+
+	/*
+	 * If something goes wrong during CPU up/down, we'll fall back to
+	 * the default pwq covering whole @attrs->cpumask.  Always create
+	 * it even if we don't use it immediately.
+	 */
+	ctx->dfl_pwq = alloc_unbound_pwq(wq, new_attrs);
+	if (!ctx->dfl_pwq)
+		goto out_free;
+
+	for_each_node(node) {
+		if (wq_calc_node_cpumask(new_attrs, node, -1, tmp_attrs->cpumask)) {
+			ctx->pwq_tbl[node] = alloc_unbound_pwq(wq, tmp_attrs);
+			if (!ctx->pwq_tbl[node])
+				goto out_free;
+		} else {
+			ctx->dfl_pwq->refcnt++;
+			ctx->pwq_tbl[node] = ctx->dfl_pwq;
+		}
+	}
+
+	/* save the user configured attrs and sanitize it. */
+	copy_workqueue_attrs(new_attrs, attrs);
+	cpumask_and(new_attrs->cpumask, new_attrs->cpumask, cpu_possible_mask);
+	ctx->attrs = new_attrs;
+
+	ctx->wq = wq;
+	free_workqueue_attrs(tmp_attrs);
+	return ctx;
+
+out_free:
+	free_workqueue_attrs(tmp_attrs);
+	free_workqueue_attrs(new_attrs);
+	apply_wqattrs_cleanup(ctx);
+	return NULL;
+}
+
+/* set attrs and install prepared pwqs, @ctx points to old pwqs on return */
+static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx)
+{
+	int node;
+
+	/* all pwqs have been created successfully, let's install'em */
+	mutex_lock(&ctx->wq->mutex);
+
+	copy_workqueue_attrs(ctx->wq->unbound_attrs, ctx->attrs);
+
+	/* save the previous pwq and install the new one */
+	for_each_node(node)
+		ctx->pwq_tbl[node] = numa_pwq_tbl_install(ctx->wq, node,
+							  ctx->pwq_tbl[node]);
+
+	/* @dfl_pwq might not have been used, ensure it's linked */
+	link_pwq(ctx->dfl_pwq);
+	swap(ctx->wq->dfl_pwq, ctx->dfl_pwq);
+
+	mutex_unlock(&ctx->wq->mutex);
+}
+
+static void apply_wqattrs_lock(void)
+{
+	/* CPUs should stay stable across pwq creations and installations */
+	cpus_read_lock();
+	mutex_lock(&wq_pool_mutex);
+}
+
+static void apply_wqattrs_unlock(void)
+{
+	mutex_unlock(&wq_pool_mutex);
+	cpus_read_unlock();
+}
+
+static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
+					const struct workqueue_attrs *attrs)
+{
+	struct apply_wqattrs_ctx *ctx;
+
+	/* only unbound workqueues can change attributes */
+	if (WARN_ON(!(wq->flags & WQ_UNBOUND)))
+		return -EINVAL;
+
+	/* creating multiple pwqs breaks ordering guarantee */
+	if (!list_empty(&wq->pwqs)) {
+		if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
+			return -EINVAL;
+
+		wq->flags &= ~__WQ_ORDERED;
+	}
+
+	ctx = apply_wqattrs_prepare(wq, attrs, wq_unbound_cpumask);
+	if (!ctx)
+		return -ENOMEM;
+
+	/* the ctx has been prepared successfully, let's commit it */
+	apply_wqattrs_commit(ctx);
+	apply_wqattrs_cleanup(ctx);
+
+	return 0;
+}
+
+/**
+ * apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue
+ * @wq: the target workqueue
+ * @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs()
+ *
+ * Apply @attrs to an unbound workqueue @wq.  Unless disabled, on NUMA
+ * machines, this function maps a separate pwq to each NUMA node with
+ * possibles CPUs in @attrs->cpumask so that work items are affine to the
+ * NUMA node it was issued on.  Older pwqs are released as in-flight work
+ * items finish.  Note that a work item which repeatedly requeues itself
+ * back-to-back will stay on its current pwq.
+ *
+ * Performs GFP_KERNEL allocations.
+ *
+ * Assumes caller has CPU hotplug read exclusion, i.e. cpus_read_lock().
+ *
+ * Return: 0 on success and -errno on failure.
+ */
+int apply_workqueue_attrs(struct workqueue_struct *wq,
+			  const struct workqueue_attrs *attrs)
+{
+	int ret;
+
+	lockdep_assert_cpus_held();
+
+	mutex_lock(&wq_pool_mutex);
+	ret = apply_workqueue_attrs_locked(wq, attrs);
+	mutex_unlock(&wq_pool_mutex);
+
+	return ret;
+}
+
+/**
+ * wq_update_unbound_numa - update NUMA affinity of a wq for CPU hot[un]plug
+ * @wq: the target workqueue
+ * @cpu: the CPU coming up or going down
+ * @online: whether @cpu is coming up or going down
+ *
+ * This function is to be called from %CPU_DOWN_PREPARE, %CPU_ONLINE and
+ * %CPU_DOWN_FAILED.  @cpu is being hot[un]plugged, update NUMA affinity of
+ * @wq accordingly.
+ *
+ * If NUMA affinity can't be adjusted due to memory allocation failure, it
+ * falls back to @wq->dfl_pwq which may not be optimal but is always
+ * correct.
+ *
+ * Note that when the last allowed CPU of a NUMA node goes offline for a
+ * workqueue with a cpumask spanning multiple nodes, the workers which were
+ * already executing the work items for the workqueue will lose their CPU
+ * affinity and may execute on any CPU.  This is similar to how per-cpu
+ * workqueues behave on CPU_DOWN.  If a workqueue user wants strict
+ * affinity, it's the user's responsibility to flush the work item from
+ * CPU_DOWN_PREPARE.
+ */
+static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
+				   bool online)
+{
+	int node = cpu_to_node(cpu);
+	int cpu_off = online ? -1 : cpu;
+	struct pool_workqueue *old_pwq = NULL, *pwq;
+	struct workqueue_attrs *target_attrs;
+	cpumask_t *cpumask;
+
+	lockdep_assert_held(&wq_pool_mutex);
+
+	if (!wq_numa_enabled || !(wq->flags & WQ_UNBOUND) ||
+	    wq->unbound_attrs->no_numa)
+		return;
+
+	/*
+	 * We don't wanna alloc/free wq_attrs for each wq for each CPU.
+	 * Let's use a preallocated one.  The following buf is protected by
+	 * CPU hotplug exclusion.
+	 */
+	target_attrs = wq_update_unbound_numa_attrs_buf;
+	cpumask = target_attrs->cpumask;
+
+	copy_workqueue_attrs(target_attrs, wq->unbound_attrs);
+	pwq = unbound_pwq_by_node(wq, node);
+
+	/*
+	 * Let's determine what needs to be done.  If the target cpumask is
+	 * different from the default pwq's, we need to compare it to @pwq's
+	 * and create a new one if they don't match.  If the target cpumask
+	 * equals the default pwq's, the default pwq should be used.
+	 */
+	if (wq_calc_node_cpumask(wq->dfl_pwq->pool->attrs, node, cpu_off, cpumask)) {
+		if (cpumask_equal(cpumask, pwq->pool->attrs->cpumask))
+			return;
+	} else {
+		goto use_dfl_pwq;
+	}
+
+	/* create a new pwq */
+	pwq = alloc_unbound_pwq(wq, target_attrs);
+	if (!pwq) {
+		pr_warn("workqueue: allocation failed while updating NUMA affinity of \"%s\"\n",
+			wq->name);
+		goto use_dfl_pwq;
+	}
+
+	/* Install the new pwq. */
+	mutex_lock(&wq->mutex);
+	old_pwq = numa_pwq_tbl_install(wq, node, pwq);
+	goto out_unlock;
+
+use_dfl_pwq:
+	mutex_lock(&wq->mutex);
+	raw_spin_lock_irq(&wq->dfl_pwq->pool->lock);
+	get_pwq(wq->dfl_pwq);
+	raw_spin_unlock_irq(&wq->dfl_pwq->pool->lock);
+	old_pwq = numa_pwq_tbl_install(wq, node, wq->dfl_pwq);
+out_unlock:
+	mutex_unlock(&wq->mutex);
+	put_pwq_unlocked(old_pwq);
+}
+
+static int alloc_and_link_pwqs(struct workqueue_struct *wq)
+{
+	bool highpri = wq->flags & WQ_HIGHPRI;
+	int cpu, ret;
+
+	if (!(wq->flags & WQ_UNBOUND)) {
+		wq->cpu_pwqs = alloc_percpu(struct pool_workqueue);
+		if (!wq->cpu_pwqs)
+			return -ENOMEM;
+
+		for_each_possible_cpu(cpu) {
+			struct pool_workqueue *pwq =
+				per_cpu_ptr(wq->cpu_pwqs, cpu);
+			struct worker_pool *cpu_pools =
+				per_cpu(cpu_worker_pools, cpu);
+
+			init_pwq(pwq, wq, &cpu_pools[highpri]);
+
+			mutex_lock(&wq->mutex);
+			link_pwq(pwq);
+			mutex_unlock(&wq->mutex);
+		}
+		return 0;
+	}
+
+	cpus_read_lock();
+	if (wq->flags & __WQ_ORDERED) {
+		ret = apply_workqueue_attrs(wq, ordered_wq_attrs[highpri]);
+		/* there should only be single pwq for ordering guarantee */
+		WARN(!ret && (wq->pwqs.next != &wq->dfl_pwq->pwqs_node ||
+			      wq->pwqs.prev != &wq->dfl_pwq->pwqs_node),
+		     "ordering guarantee broken for workqueue %s\n", wq->name);
+	} else {
+		ret = apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]);
+	}
+	cpus_read_unlock();
+
+	return ret;
+}
+
+static int wq_clamp_max_active(int max_active, unsigned int flags,
+			       const char *name)
+{
+	int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE;
+
+	if (max_active < 1 || max_active > lim)
+		pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n",
+			max_active, name, 1, lim);
+
+	return clamp_val(max_active, 1, lim);
+}
+
+/*
+ * Workqueues which may be used during memory reclaim should have a rescuer
+ * to guarantee forward progress.
+ */
+static int init_rescuer(struct workqueue_struct *wq)
+{
+	struct worker *rescuer;
+	int ret;
+
+	if (!(wq->flags & WQ_MEM_RECLAIM))
+		return 0;
+
+	rescuer = alloc_worker(NUMA_NO_NODE);
+	if (!rescuer)
+		return -ENOMEM;
+
+	rescuer->rescue_wq = wq;
+	rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", wq->name);
+	if (IS_ERR(rescuer->task)) {
+		ret = PTR_ERR(rescuer->task);
+		kfree(rescuer);
+		return ret;
+	}
+
+	wq->rescuer = rescuer;
+	kthread_bind_mask(rescuer->task, cpu_possible_mask);
+	wake_up_process(rescuer->task);
+
+	return 0;
+}
+
+__printf(1, 4)
+struct workqueue_struct *alloc_workqueue(const char *fmt,
+					 unsigned int flags,
+					 int max_active, ...)
+{
+	size_t tbl_size = 0;
+	va_list args;
+	struct workqueue_struct *wq;
+	struct pool_workqueue *pwq;
+
+	/*
+	 * Unbound && max_active == 1 used to imply ordered, which is no
+	 * longer the case on NUMA machines due to per-node pools.  While
+	 * alloc_ordered_workqueue() is the right way to create an ordered
+	 * workqueue, keep the previous behavior to avoid subtle breakages
+	 * on NUMA.
+	 */
+	if ((flags & WQ_UNBOUND) && max_active == 1)
+		flags |= __WQ_ORDERED;
+
+	/* see the comment above the definition of WQ_POWER_EFFICIENT */
+	if ((flags & WQ_POWER_EFFICIENT) && wq_power_efficient)
+		flags |= WQ_UNBOUND;
+
+	/* allocate wq and format name */
+	if (flags & WQ_UNBOUND)
+		tbl_size = nr_node_ids * sizeof(wq->numa_pwq_tbl[0]);
+
+	wq = kzalloc(sizeof(*wq) + tbl_size, GFP_KERNEL);
+	if (!wq)
+		return NULL;
+
+	if (flags & WQ_UNBOUND) {
+		wq->unbound_attrs = alloc_workqueue_attrs();
+		if (!wq->unbound_attrs)
+			goto err_free_wq;
+	}
+
+	va_start(args, max_active);
+	vsnprintf(wq->name, sizeof(wq->name), fmt, args);
+	va_end(args);
+
+	max_active = max_active ?: WQ_DFL_ACTIVE;
+	max_active = wq_clamp_max_active(max_active, flags, wq->name);
+
+	/* init wq */
+	wq->flags = flags;
+	wq->saved_max_active = max_active;
+	mutex_init(&wq->mutex);
+	atomic_set(&wq->nr_pwqs_to_flush, 0);
+	INIT_LIST_HEAD(&wq->pwqs);
+	INIT_LIST_HEAD(&wq->flusher_queue);
+	INIT_LIST_HEAD(&wq->flusher_overflow);
+	INIT_LIST_HEAD(&wq->maydays);
+
+	wq_init_lockdep(wq);
+	INIT_LIST_HEAD(&wq->list);
+
+	if (alloc_and_link_pwqs(wq) < 0)
+		goto err_unreg_lockdep;
+
+	if (wq_online && init_rescuer(wq) < 0)
+		goto err_destroy;
+
+	if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
+		goto err_destroy;
+
+	/*
+	 * wq_pool_mutex protects global freeze state and workqueues list.
+	 * Grab it, adjust max_active and add the new @wq to workqueues
+	 * list.
+	 */
+	mutex_lock(&wq_pool_mutex);
+
+	mutex_lock(&wq->mutex);
+	for_each_pwq(pwq, wq)
+		pwq_adjust_max_active(pwq);
+	mutex_unlock(&wq->mutex);
+
+	list_add_tail_rcu(&wq->list, &workqueues);
+
+	mutex_unlock(&wq_pool_mutex);
+
+	return wq;
+
+err_unreg_lockdep:
+	wq_unregister_lockdep(wq);
+	wq_free_lockdep(wq);
+err_free_wq:
+	free_workqueue_attrs(wq->unbound_attrs);
+	kfree(wq);
+	return NULL;
+err_destroy:
+	destroy_workqueue(wq);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(alloc_workqueue);
+
+static bool pwq_busy(struct pool_workqueue *pwq)
+{
+	int i;
+
+	for (i = 0; i < WORK_NR_COLORS; i++)
+		if (pwq->nr_in_flight[i])
+			return true;
+
+	if ((pwq != pwq->wq->dfl_pwq) && (pwq->refcnt > 1))
+		return true;
+	if (pwq->nr_active || !list_empty(&pwq->inactive_works))
+		return true;
+
+	return false;
+}
+
+/**
+ * destroy_workqueue - safely terminate a workqueue
+ * @wq: target workqueue
+ *
+ * Safely destroy a workqueue. All work currently pending will be done first.
+ */
+void destroy_workqueue(struct workqueue_struct *wq)
+{
+	struct pool_workqueue *pwq;
+	int node;
+
+	/*
+	 * Remove it from sysfs first so that sanity check failure doesn't
+	 * lead to sysfs name conflicts.
+	 */
+	workqueue_sysfs_unregister(wq);
+
+	/* drain it before proceeding with destruction */
+	drain_workqueue(wq);
+
+	/* kill rescuer, if sanity checks fail, leave it w/o rescuer */
+	if (wq->rescuer) {
+		struct worker *rescuer = wq->rescuer;
+
+		/* this prevents new queueing */
+		raw_spin_lock_irq(&wq_mayday_lock);
+		wq->rescuer = NULL;
+		raw_spin_unlock_irq(&wq_mayday_lock);
+
+		/* rescuer will empty maydays list before exiting */
+		kthread_stop(rescuer->task);
+		kfree(rescuer);
+	}
+
+	/*
+	 * Sanity checks - grab all the locks so that we wait for all
+	 * in-flight operations which may do put_pwq().
+	 */
+	mutex_lock(&wq_pool_mutex);
+	mutex_lock(&wq->mutex);
+	for_each_pwq(pwq, wq) {
+		raw_spin_lock_irq(&pwq->pool->lock);
+		if (WARN_ON(pwq_busy(pwq))) {
+			pr_warn("%s: %s has the following busy pwq\n",
+				__func__, wq->name);
+			show_pwq(pwq);
+			raw_spin_unlock_irq(&pwq->pool->lock);
+			mutex_unlock(&wq->mutex);
+			mutex_unlock(&wq_pool_mutex);
+			show_one_workqueue(wq);
+			return;
+		}
+		raw_spin_unlock_irq(&pwq->pool->lock);
+	}
+	mutex_unlock(&wq->mutex);
+
+	/*
+	 * wq list is used to freeze wq, remove from list after
+	 * flushing is complete in case freeze races us.
+	 */
+	list_del_rcu(&wq->list);
+	mutex_unlock(&wq_pool_mutex);
+
+	if (!(wq->flags & WQ_UNBOUND)) {
+		wq_unregister_lockdep(wq);
+		/*
+		 * The base ref is never dropped on per-cpu pwqs.  Directly
+		 * schedule RCU free.
+		 */
+		call_rcu(&wq->rcu, rcu_free_wq);
+	} else {
+		/*
+		 * We're the sole accessor of @wq at this point.  Directly
+		 * access numa_pwq_tbl[] and dfl_pwq to put the base refs.
+		 * @wq will be freed when the last pwq is released.
+		 */
+		for_each_node(node) {
+			pwq = rcu_access_pointer(wq->numa_pwq_tbl[node]);
+			RCU_INIT_POINTER(wq->numa_pwq_tbl[node], NULL);
+			put_pwq_unlocked(pwq);
+		}
+
+		/*
+		 * Put dfl_pwq.  @wq may be freed any time after dfl_pwq is
+		 * put.  Don't access it afterwards.
+		 */
+		pwq = wq->dfl_pwq;
+		wq->dfl_pwq = NULL;
+		put_pwq_unlocked(pwq);
+	}
+}
+EXPORT_SYMBOL_GPL(destroy_workqueue);
+
+/**
+ * workqueue_set_max_active - adjust max_active of a workqueue
+ * @wq: target workqueue
+ * @max_active: new max_active value.
+ *
+ * Set max_active of @wq to @max_active.
+ *
+ * CONTEXT:
+ * Don't call from IRQ context.
+ */
+void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
+{
+	struct pool_workqueue *pwq;
+
+	/* disallow meddling with max_active for ordered workqueues */
+	if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
+		return;
+
+	max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
+
+	mutex_lock(&wq->mutex);
+
+	wq->flags &= ~__WQ_ORDERED;
+	wq->saved_max_active = max_active;
+
+	for_each_pwq(pwq, wq)
+		pwq_adjust_max_active(pwq);
+
+	mutex_unlock(&wq->mutex);
+}
+EXPORT_SYMBOL_GPL(workqueue_set_max_active);
+
+/**
+ * current_work - retrieve %current task's work struct
+ *
+ * Determine if %current task is a workqueue worker and what it's working on.
+ * Useful to find out the context that the %current task is running in.
+ *
+ * Return: work struct if %current task is a workqueue worker, %NULL otherwise.
+ */
+struct work_struct *current_work(void)
+{
+	struct worker *worker = current_wq_worker();
+
+	return worker ? worker->current_work : NULL;
+}
+EXPORT_SYMBOL(current_work);
+
+/**
+ * current_is_workqueue_rescuer - is %current workqueue rescuer?
+ *
+ * Determine whether %current is a workqueue rescuer.  Can be used from
+ * work functions to determine whether it's being run off the rescuer task.
+ *
+ * Return: %true if %current is a workqueue rescuer. %false otherwise.
+ */
+bool current_is_workqueue_rescuer(void)
+{
+	struct worker *worker = current_wq_worker();
+
+	return worker && worker->rescue_wq;
+}
+
+/**
+ * workqueue_congested - test whether a workqueue is congested
+ * @cpu: CPU in question
+ * @wq: target workqueue
+ *
+ * Test whether @wq's cpu workqueue for @cpu is congested.  There is
+ * no synchronization around this function and the test result is
+ * unreliable and only useful as advisory hints or for debugging.
+ *
+ * If @cpu is WORK_CPU_UNBOUND, the test is performed on the local CPU.
+ * Note that both per-cpu and unbound workqueues may be associated with
+ * multiple pool_workqueues which have separate congested states.  A
+ * workqueue being congested on one CPU doesn't mean the workqueue is also
+ * contested on other CPUs / NUMA nodes.
+ *
+ * Return:
+ * %true if congested, %false otherwise.
+ */
+bool workqueue_congested(int cpu, struct workqueue_struct *wq)
+{
+	struct pool_workqueue *pwq;
+	bool ret;
+
+	rcu_read_lock();
+	preempt_disable();
+
+	if (cpu == WORK_CPU_UNBOUND)
+		cpu = smp_processor_id();
+
+	if (!(wq->flags & WQ_UNBOUND))
+		pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
+	else
+		pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
+
+	ret = !list_empty(&pwq->inactive_works);
+	preempt_enable();
+	rcu_read_unlock();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(workqueue_congested);
+
+/**
+ * work_busy - test whether a work is currently pending or running
+ * @work: the work to be tested
+ *
+ * Test whether @work is currently pending or running.  There is no
+ * synchronization around this function and the test result is
+ * unreliable and only useful as advisory hints or for debugging.
+ *
+ * Return:
+ * OR'd bitmask of WORK_BUSY_* bits.
+ */
+unsigned int work_busy(struct work_struct *work)
+{
+	struct worker_pool *pool;
+	unsigned long flags;
+	unsigned int ret = 0;
+
+	if (work_pending(work))
+		ret |= WORK_BUSY_PENDING;
+
+	rcu_read_lock();
+	pool = get_work_pool(work);
+	if (pool) {
+		raw_spin_lock_irqsave(&pool->lock, flags);
+		if (find_worker_executing_work(pool, work))
+			ret |= WORK_BUSY_RUNNING;
+		raw_spin_unlock_irqrestore(&pool->lock, flags);
+	}
+	rcu_read_unlock();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(work_busy);
+
+/**
+ * set_worker_desc - set description for the current work item
+ * @fmt: printf-style format string
+ * @...: arguments for the format string
+ *
+ * This function can be called by a running work function to describe what
+ * the work item is about.  If the worker task gets dumped, this
+ * information will be printed out together to help debugging.  The
+ * description can be at most WORKER_DESC_LEN including the trailing '\0'.
+ */
+void set_worker_desc(const char *fmt, ...)
+{
+	struct worker *worker = current_wq_worker();
+	va_list args;
+
+	if (worker) {
+		va_start(args, fmt);
+		vsnprintf(worker->desc, sizeof(worker->desc), fmt, args);
+		va_end(args);
+	}
+}
+EXPORT_SYMBOL_GPL(set_worker_desc);
+
+/**
+ * print_worker_info - print out worker information and description
+ * @log_lvl: the log level to use when printing
+ * @task: target task
+ *
+ * If @task is a worker and currently executing a work item, print out the
+ * name of the workqueue being serviced and worker description set with
+ * set_worker_desc() by the currently executing work item.
+ *
+ * This function can be safely called on any task as long as the
+ * task_struct itself is accessible.  While safe, this function isn't
+ * synchronized and may print out mixups or garbages of limited length.
+ */
+void print_worker_info(const char *log_lvl, struct task_struct *task)
+{
+	work_func_t *fn = NULL;
+	char name[WQ_NAME_LEN] = { };
+	char desc[WORKER_DESC_LEN] = { };
+	struct pool_workqueue *pwq = NULL;
+	struct workqueue_struct *wq = NULL;
+	struct worker *worker;
+
+	if (!(task->flags & PF_WQ_WORKER))
+		return;
+
+	/*
+	 * This function is called without any synchronization and @task
+	 * could be in any state.  Be careful with dereferences.
+	 */
+	worker = kthread_probe_data(task);
+
+	/*
+	 * Carefully copy the associated workqueue's workfn, name and desc.
+	 * Keep the original last '\0' in case the original is garbage.
+	 */
+	copy_from_kernel_nofault(&fn, &worker->current_func, sizeof(fn));
+	copy_from_kernel_nofault(&pwq, &worker->current_pwq, sizeof(pwq));
+	copy_from_kernel_nofault(&wq, &pwq->wq, sizeof(wq));
+	copy_from_kernel_nofault(name, wq->name, sizeof(name) - 1);
+	copy_from_kernel_nofault(desc, worker->desc, sizeof(desc) - 1);
+
+	if (fn || name[0] || desc[0]) {
+		printk("%sWorkqueue: %s %ps", log_lvl, name, fn);
+		if (strcmp(name, desc))
+			pr_cont(" (%s)", desc);
+		pr_cont("\n");
+	}
+}
+
+static void pr_cont_pool_info(struct worker_pool *pool)
+{
+	pr_cont(" cpus=%*pbl", nr_cpumask_bits, pool->attrs->cpumask);
+	if (pool->node != NUMA_NO_NODE)
+		pr_cont(" node=%d", pool->node);
+	pr_cont(" flags=0x%x nice=%d", pool->flags, pool->attrs->nice);
+}
+
+static void pr_cont_work(bool comma, struct work_struct *work)
+{
+	if (work->func == wq_barrier_func) {
+		struct wq_barrier *barr;
+
+		barr = container_of(work, struct wq_barrier, work);
+
+		pr_cont("%s BAR(%d)", comma ? "," : "",
+			task_pid_nr(barr->task));
+	} else {
+		pr_cont("%s %ps", comma ? "," : "", work->func);
+	}
+}
+
+static void show_pwq(struct pool_workqueue *pwq)
+{
+	struct worker_pool *pool = pwq->pool;
+	struct work_struct *work;
+	struct worker *worker;
+	bool has_in_flight = false, has_pending = false;
+	int bkt;
+
+	pr_info("  pwq %d:", pool->id);
+	pr_cont_pool_info(pool);
+
+	pr_cont(" active=%d/%d refcnt=%d%s\n",
+		pwq->nr_active, pwq->max_active, pwq->refcnt,
+		!list_empty(&pwq->mayday_node) ? " MAYDAY" : "");
+
+	hash_for_each(pool->busy_hash, bkt, worker, hentry) {
+		if (worker->current_pwq == pwq) {
+			has_in_flight = true;
+			break;
+		}
+	}
+	if (has_in_flight) {
+		bool comma = false;
+
+		pr_info("    in-flight:");
+		hash_for_each(pool->busy_hash, bkt, worker, hentry) {
+			if (worker->current_pwq != pwq)
+				continue;
+
+			pr_cont("%s %d%s:%ps", comma ? "," : "",
+				task_pid_nr(worker->task),
+				worker->rescue_wq ? "(RESCUER)" : "",
+				worker->current_func);
+			list_for_each_entry(work, &worker->scheduled, entry)
+				pr_cont_work(false, work);
+			comma = true;
+		}
+		pr_cont("\n");
+	}
+
+	list_for_each_entry(work, &pool->worklist, entry) {
+		if (get_work_pwq(work) == pwq) {
+			has_pending = true;
+			break;
+		}
+	}
+	if (has_pending) {
+		bool comma = false;
+
+		pr_info("    pending:");
+		list_for_each_entry(work, &pool->worklist, entry) {
+			if (get_work_pwq(work) != pwq)
+				continue;
+
+			pr_cont_work(comma, work);
+			comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED);
+		}
+		pr_cont("\n");
+	}
+
+	if (!list_empty(&pwq->inactive_works)) {
+		bool comma = false;
+
+		pr_info("    inactive:");
+		list_for_each_entry(work, &pwq->inactive_works, entry) {
+			pr_cont_work(comma, work);
+			comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED);
+		}
+		pr_cont("\n");
+	}
+}
+
+/**
+ * show_one_workqueue - dump state of specified workqueue
+ * @wq: workqueue whose state will be printed
+ */
+void show_one_workqueue(struct workqueue_struct *wq)
+{
+	struct pool_workqueue *pwq;
+	bool idle = true;
+	unsigned long flags;
+
+	for_each_pwq(pwq, wq) {
+		if (pwq->nr_active || !list_empty(&pwq->inactive_works)) {
+			idle = false;
+			break;
+		}
+	}
+	if (idle) /* Nothing to print for idle workqueue */
+		return;
+
+	pr_info("workqueue %s: flags=0x%x\n", wq->name, wq->flags);
+
+	for_each_pwq(pwq, wq) {
+		raw_spin_lock_irqsave(&pwq->pool->lock, flags);
+		if (pwq->nr_active || !list_empty(&pwq->inactive_works)) {
+			/*
+			 * Defer printing to avoid deadlocks in console
+			 * drivers that queue work while holding locks
+			 * also taken in their write paths.
+			 */
+			printk_deferred_enter();
+			show_pwq(pwq);
+			printk_deferred_exit();
+		}
+		raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
+		/*
+		 * We could be printing a lot from atomic context, e.g.
+		 * sysrq-t -> show_all_workqueues(). Avoid triggering
+		 * hard lockup.
+		 */
+		touch_nmi_watchdog();
+	}
+
+}
+
+/**
+ * show_one_worker_pool - dump state of specified worker pool
+ * @pool: worker pool whose state will be printed
+ */
+static void show_one_worker_pool(struct worker_pool *pool)
+{
+	struct worker *worker;
+	bool first = true;
+	unsigned long flags;
+	unsigned long hung = 0;
+
+	raw_spin_lock_irqsave(&pool->lock, flags);
+	if (pool->nr_workers == pool->nr_idle)
+		goto next_pool;
+
+	/* How long the first pending work is waiting for a worker. */
+	if (!list_empty(&pool->worklist))
+		hung = jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000;
+
+	/*
+	 * Defer printing to avoid deadlocks in console drivers that
+	 * queue work while holding locks also taken in their write
+	 * paths.
+	 */
+	printk_deferred_enter();
+	pr_info("pool %d:", pool->id);
+	pr_cont_pool_info(pool);
+	pr_cont(" hung=%lus workers=%d", hung, pool->nr_workers);
+	if (pool->manager)
+		pr_cont(" manager: %d",
+			task_pid_nr(pool->manager->task));
+	list_for_each_entry(worker, &pool->idle_list, entry) {
+		pr_cont(" %s%d", first ? "idle: " : "",
+			task_pid_nr(worker->task));
+		first = false;
+	}
+	pr_cont("\n");
+	printk_deferred_exit();
+next_pool:
+	raw_spin_unlock_irqrestore(&pool->lock, flags);
+	/*
+	 * We could be printing a lot from atomic context, e.g.
+	 * sysrq-t -> show_all_workqueues(). Avoid triggering
+	 * hard lockup.
+	 */
+	touch_nmi_watchdog();
+
+}
+
+/**
+ * show_all_workqueues - dump workqueue state
+ *
+ * Called from a sysrq handler or try_to_freeze_tasks() and prints out
+ * all busy workqueues and pools.
+ */
+void show_all_workqueues(void)
+{
+	struct workqueue_struct *wq;
+	struct worker_pool *pool;
+	int pi;
+
+	rcu_read_lock();
+
+	pr_info("Showing busy workqueues and worker pools:\n");
+
+	list_for_each_entry_rcu(wq, &workqueues, list)
+		show_one_workqueue(wq);
+
+	for_each_pool(pool, pi)
+		show_one_worker_pool(pool);
+
+	rcu_read_unlock();
+}
+
+/* used to show worker information through /proc/PID/{comm,stat,status} */
+void wq_worker_comm(char *buf, size_t size, struct task_struct *task)
+{
+	int off;
+
+	/* always show the actual comm */
+	off = strscpy(buf, task->comm, size);
+	if (off < 0)
+		return;
+
+	/* stabilize PF_WQ_WORKER and worker pool association */
+	mutex_lock(&wq_pool_attach_mutex);
+
+	if (task->flags & PF_WQ_WORKER) {
+		struct worker *worker = kthread_data(task);
+		struct worker_pool *pool = worker->pool;
+
+		if (pool) {
+			raw_spin_lock_irq(&pool->lock);
+			/*
+			 * ->desc tracks information (wq name or
+			 * set_worker_desc()) for the latest execution.  If
+			 * current, prepend '+', otherwise '-'.
+			 */
+			if (worker->desc[0] != '\0') {
+				if (worker->current_work)
+					scnprintf(buf + off, size - off, "+%s",
+						  worker->desc);
+				else
+					scnprintf(buf + off, size - off, "-%s",
+						  worker->desc);
+			}
+			raw_spin_unlock_irq(&pool->lock);
+		}
+	}
+
+	mutex_unlock(&wq_pool_attach_mutex);
+}
+
+#ifdef CONFIG_SMP
+
+/*
+ * CPU hotplug.
+ *
+ * There are two challenges in supporting CPU hotplug.  Firstly, there
+ * are a lot of assumptions on strong associations among work, pwq and
+ * pool which make migrating pending and scheduled works very
+ * difficult to implement without impacting hot paths.  Secondly,
+ * worker pools serve mix of short, long and very long running works making
+ * blocked draining impractical.
+ *
+ * This is solved by allowing the pools to be disassociated from the CPU
+ * running as an unbound one and allowing it to be reattached later if the
+ * cpu comes back online.
+ */
+
+static void unbind_workers(int cpu)
+{
+	struct worker_pool *pool;
+	struct worker *worker;
+
+	for_each_cpu_worker_pool(pool, cpu) {
+		mutex_lock(&wq_pool_attach_mutex);
+		raw_spin_lock_irq(&pool->lock);
+
+		/*
+		 * We've blocked all attach/detach operations. Make all workers
+		 * unbound and set DISASSOCIATED.  Before this, all workers
+		 * must be on the cpu.  After this, they may become diasporas.
+		 * And the preemption disabled section in their sched callbacks
+		 * are guaranteed to see WORKER_UNBOUND since the code here
+		 * is on the same cpu.
+		 */
+		for_each_pool_worker(worker, pool)
+			worker->flags |= WORKER_UNBOUND;
+
+		pool->flags |= POOL_DISASSOCIATED;
+
+		/*
+		 * The handling of nr_running in sched callbacks are disabled
+		 * now.  Zap nr_running.  After this, nr_running stays zero and
+		 * need_more_worker() and keep_working() are always true as
+		 * long as the worklist is not empty.  This pool now behaves as
+		 * an unbound (in terms of concurrency management) pool which
+		 * are served by workers tied to the pool.
+		 */
+		pool->nr_running = 0;
+
+		/*
+		 * With concurrency management just turned off, a busy
+		 * worker blocking could lead to lengthy stalls.  Kick off
+		 * unbound chain execution of currently pending work items.
+		 */
+		wake_up_worker(pool);
+
+		raw_spin_unlock_irq(&pool->lock);
+
+		for_each_pool_worker(worker, pool) {
+			kthread_set_per_cpu(worker->task, -1);
+			if (cpumask_intersects(wq_unbound_cpumask, cpu_active_mask))
+				WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, wq_unbound_cpumask) < 0);
+			else
+				WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_possible_mask) < 0);
+		}
+
+		mutex_unlock(&wq_pool_attach_mutex);
+	}
+}
+
+/**
+ * rebind_workers - rebind all workers of a pool to the associated CPU
+ * @pool: pool of interest
+ *
+ * @pool->cpu is coming online.  Rebind all workers to the CPU.
+ */
+static void rebind_workers(struct worker_pool *pool)
+{
+	struct worker *worker;
+
+	lockdep_assert_held(&wq_pool_attach_mutex);
+
+	/*
+	 * Restore CPU affinity of all workers.  As all idle workers should
+	 * be on the run-queue of the associated CPU before any local
+	 * wake-ups for concurrency management happen, restore CPU affinity
+	 * of all workers first and then clear UNBOUND.  As we're called
+	 * from CPU_ONLINE, the following shouldn't fail.
+	 */
+	for_each_pool_worker(worker, pool) {
+		kthread_set_per_cpu(worker->task, pool->cpu);
+		WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task,
+						  pool->attrs->cpumask) < 0);
+	}
+
+	raw_spin_lock_irq(&pool->lock);
+
+	pool->flags &= ~POOL_DISASSOCIATED;
+
+	for_each_pool_worker(worker, pool) {
+		unsigned int worker_flags = worker->flags;
+
+		/*
+		 * We want to clear UNBOUND but can't directly call
+		 * worker_clr_flags() or adjust nr_running.  Atomically
+		 * replace UNBOUND with another NOT_RUNNING flag REBOUND.
+		 * @worker will clear REBOUND using worker_clr_flags() when
+		 * it initiates the next execution cycle thus restoring
+		 * concurrency management.  Note that when or whether
+		 * @worker clears REBOUND doesn't affect correctness.
+		 *
+		 * WRITE_ONCE() is necessary because @worker->flags may be
+		 * tested without holding any lock in
+		 * wq_worker_running().  Without it, NOT_RUNNING test may
+		 * fail incorrectly leading to premature concurrency
+		 * management operations.
+		 */
+		WARN_ON_ONCE(!(worker_flags & WORKER_UNBOUND));
+		worker_flags |= WORKER_REBOUND;
+		worker_flags &= ~WORKER_UNBOUND;
+		WRITE_ONCE(worker->flags, worker_flags);
+	}
+
+	raw_spin_unlock_irq(&pool->lock);
+}
+
+/**
+ * restore_unbound_workers_cpumask - restore cpumask of unbound workers
+ * @pool: unbound pool of interest
+ * @cpu: the CPU which is coming up
+ *
+ * An unbound pool may end up with a cpumask which doesn't have any online
+ * CPUs.  When a worker of such pool get scheduled, the scheduler resets
+ * its cpus_allowed.  If @cpu is in @pool's cpumask which didn't have any
+ * online CPU before, cpus_allowed of all its workers should be restored.
+ */
+static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu)
+{
+	static cpumask_t cpumask;
+	struct worker *worker;
+
+	lockdep_assert_held(&wq_pool_attach_mutex);
+
+	/* is @cpu allowed for @pool? */
+	if (!cpumask_test_cpu(cpu, pool->attrs->cpumask))
+		return;
+
+	cpumask_and(&cpumask, pool->attrs->cpumask, cpu_online_mask);
+
+	/* as we're called from CPU_ONLINE, the following shouldn't fail */
+	for_each_pool_worker(worker, pool)
+		WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, &cpumask) < 0);
+}
+
+int workqueue_prepare_cpu(unsigned int cpu)
+{
+	struct worker_pool *pool;
+
+	for_each_cpu_worker_pool(pool, cpu) {
+		if (pool->nr_workers)
+			continue;
+		if (!create_worker(pool))
+			return -ENOMEM;
+	}
+	return 0;
+}
+
+int workqueue_online_cpu(unsigned int cpu)
+{
+	struct worker_pool *pool;
+	struct workqueue_struct *wq;
+	int pi;
+
+	mutex_lock(&wq_pool_mutex);
+
+	for_each_pool(pool, pi) {
+		mutex_lock(&wq_pool_attach_mutex);
+
+		if (pool->cpu == cpu)
+			rebind_workers(pool);
+		else if (pool->cpu < 0)
+			restore_unbound_workers_cpumask(pool, cpu);
+
+		mutex_unlock(&wq_pool_attach_mutex);
+	}
+
+	/* update NUMA affinity of unbound workqueues */
+	list_for_each_entry(wq, &workqueues, list)
+		wq_update_unbound_numa(wq, cpu, true);
+
+	mutex_unlock(&wq_pool_mutex);
+	return 0;
+}
+
+int workqueue_offline_cpu(unsigned int cpu)
+{
+	struct workqueue_struct *wq;
+
+	/* unbinding per-cpu workers should happen on the local CPU */
+	if (WARN_ON(cpu != smp_processor_id()))
+		return -1;
+
+	unbind_workers(cpu);
+
+	/* update NUMA affinity of unbound workqueues */
+	mutex_lock(&wq_pool_mutex);
+	list_for_each_entry(wq, &workqueues, list)
+		wq_update_unbound_numa(wq, cpu, false);
+	mutex_unlock(&wq_pool_mutex);
+
+	return 0;
+}
+
+struct work_for_cpu {
+	struct work_struct work;
+	long (*fn)(void *);
+	void *arg;
+	long ret;
+};
+
+static void work_for_cpu_fn(struct work_struct *work)
+{
+	struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work);
+
+	wfc->ret = wfc->fn(wfc->arg);
+}
+
+/**
+ * work_on_cpu_key - run a function in thread context on a particular cpu
+ * @cpu: the cpu to run on
+ * @fn: the function to run
+ * @arg: the function arg
+ * @key: The lock class key for lock debugging purposes
+ *
+ * It is up to the caller to ensure that the cpu doesn't go offline.
+ * The caller must not hold any locks which would prevent @fn from completing.
+ *
+ * Return: The value @fn returns.
+ */
+long work_on_cpu_key(int cpu, long (*fn)(void *),
+		     void *arg, struct lock_class_key *key)
+{
+	struct work_for_cpu wfc = { .fn = fn, .arg = arg };
+
+	INIT_WORK_ONSTACK_KEY(&wfc.work, work_for_cpu_fn, key);
+	schedule_work_on(cpu, &wfc.work);
+	flush_work(&wfc.work);
+	destroy_work_on_stack(&wfc.work);
+	return wfc.ret;
+}
+EXPORT_SYMBOL_GPL(work_on_cpu_key);
+
+/**
+ * work_on_cpu_safe_key - run a function in thread context on a particular cpu
+ * @cpu: the cpu to run on
+ * @fn:  the function to run
+ * @arg: the function argument
+ * @key: The lock class key for lock debugging purposes
+ *
+ * Disables CPU hotplug and calls work_on_cpu(). The caller must not hold
+ * any locks which would prevent @fn from completing.
+ *
+ * Return: The value @fn returns.
+ */
+long work_on_cpu_safe_key(int cpu, long (*fn)(void *),
+			  void *arg, struct lock_class_key *key)
+{
+	long ret = -ENODEV;
+
+	cpus_read_lock();
+	if (cpu_online(cpu))
+		ret = work_on_cpu_key(cpu, fn, arg, key);
+	cpus_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(work_on_cpu_safe_key);
+#endif /* CONFIG_SMP */
+
+#ifdef CONFIG_FREEZER
+
+/**
+ * freeze_workqueues_begin - begin freezing workqueues
+ *
+ * Start freezing workqueues.  After this function returns, all freezable
+ * workqueues will queue new works to their inactive_works list instead of
+ * pool->worklist.
+ *
+ * CONTEXT:
+ * Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's.
+ */
+void freeze_workqueues_begin(void)
+{
+	struct workqueue_struct *wq;
+	struct pool_workqueue *pwq;
+
+	mutex_lock(&wq_pool_mutex);
+
+	WARN_ON_ONCE(workqueue_freezing);
+	workqueue_freezing = true;
+
+	list_for_each_entry(wq, &workqueues, list) {
+		mutex_lock(&wq->mutex);
+		for_each_pwq(pwq, wq)
+			pwq_adjust_max_active(pwq);
+		mutex_unlock(&wq->mutex);
+	}
+
+	mutex_unlock(&wq_pool_mutex);
+}
+
+/**
+ * freeze_workqueues_busy - are freezable workqueues still busy?
+ *
+ * Check whether freezing is complete.  This function must be called
+ * between freeze_workqueues_begin() and thaw_workqueues().
+ *
+ * CONTEXT:
+ * Grabs and releases wq_pool_mutex.
+ *
+ * Return:
+ * %true if some freezable workqueues are still busy.  %false if freezing
+ * is complete.
+ */
+bool freeze_workqueues_busy(void)
+{
+	bool busy = false;
+	struct workqueue_struct *wq;
+	struct pool_workqueue *pwq;
+
+	mutex_lock(&wq_pool_mutex);
+
+	WARN_ON_ONCE(!workqueue_freezing);
+
+	list_for_each_entry(wq, &workqueues, list) {
+		if (!(wq->flags & WQ_FREEZABLE))
+			continue;
+		/*
+		 * nr_active is monotonically decreasing.  It's safe
+		 * to peek without lock.
+		 */
+		rcu_read_lock();
+		for_each_pwq(pwq, wq) {
+			WARN_ON_ONCE(pwq->nr_active < 0);
+			if (pwq->nr_active) {
+				busy = true;
+				rcu_read_unlock();
+				goto out_unlock;
+			}
+		}
+		rcu_read_unlock();
+	}
+out_unlock:
+	mutex_unlock(&wq_pool_mutex);
+	return busy;
+}
+
+/**
+ * thaw_workqueues - thaw workqueues
+ *
+ * Thaw workqueues.  Normal queueing is restored and all collected
+ * frozen works are transferred to their respective pool worklists.
+ *
+ * CONTEXT:
+ * Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's.
+ */
+void thaw_workqueues(void)
+{
+	struct workqueue_struct *wq;
+	struct pool_workqueue *pwq;
+
+	mutex_lock(&wq_pool_mutex);
+
+	if (!workqueue_freezing)
+		goto out_unlock;
+
+	workqueue_freezing = false;
+
+	/* restore max_active and repopulate worklist */
+	list_for_each_entry(wq, &workqueues, list) {
+		mutex_lock(&wq->mutex);
+		for_each_pwq(pwq, wq)
+			pwq_adjust_max_active(pwq);
+		mutex_unlock(&wq->mutex);
+	}
+
+out_unlock:
+	mutex_unlock(&wq_pool_mutex);
+}
+#endif /* CONFIG_FREEZER */
+
+static int workqueue_apply_unbound_cpumask(const cpumask_var_t unbound_cpumask)
+{
+	LIST_HEAD(ctxs);
+	int ret = 0;
+	struct workqueue_struct *wq;
+	struct apply_wqattrs_ctx *ctx, *n;
+
+	lockdep_assert_held(&wq_pool_mutex);
+
+	list_for_each_entry(wq, &workqueues, list) {
+		if (!(wq->flags & WQ_UNBOUND))
+			continue;
+
+		/* creating multiple pwqs breaks ordering guarantee */
+		if (!list_empty(&wq->pwqs)) {
+			if (wq->flags & __WQ_ORDERED_EXPLICIT)
+				continue;
+			wq->flags &= ~__WQ_ORDERED;
+		}
+
+		ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs, unbound_cpumask);
+		if (!ctx) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		list_add_tail(&ctx->list, &ctxs);
+	}
+
+	list_for_each_entry_safe(ctx, n, &ctxs, list) {
+		if (!ret)
+			apply_wqattrs_commit(ctx);
+		apply_wqattrs_cleanup(ctx);
+	}
+
+	if (!ret) {
+		mutex_lock(&wq_pool_attach_mutex);
+		cpumask_copy(wq_unbound_cpumask, unbound_cpumask);
+		mutex_unlock(&wq_pool_attach_mutex);
+	}
+	return ret;
+}
+
+/**
+ *  workqueue_set_unbound_cpumask - Set the low-level unbound cpumask
+ *  @cpumask: the cpumask to set
+ *
+ *  The low-level workqueues cpumask is a global cpumask that limits
+ *  the affinity of all unbound workqueues.  This function check the @cpumask
+ *  and apply it to all unbound workqueues and updates all pwqs of them.
+ *
+ *  Return:	0	- Success
+ *  		-EINVAL	- Invalid @cpumask
+ *  		-ENOMEM	- Failed to allocate memory for attrs or pwqs.
+ */
+int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
+{
+	int ret = -EINVAL;
+
+	/*
+	 * Not excluding isolated cpus on purpose.
+	 * If the user wishes to include them, we allow that.
+	 */
+	cpumask_and(cpumask, cpumask, cpu_possible_mask);
+	if (!cpumask_empty(cpumask)) {
+		apply_wqattrs_lock();
+		if (cpumask_equal(cpumask, wq_unbound_cpumask)) {
+			ret = 0;
+			goto out_unlock;
+		}
+
+		ret = workqueue_apply_unbound_cpumask(cpumask);
+
+out_unlock:
+		apply_wqattrs_unlock();
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_SYSFS
+/*
+ * Workqueues with WQ_SYSFS flag set is visible to userland via
+ * /sys/bus/workqueue/devices/WQ_NAME.  All visible workqueues have the
+ * following attributes.
+ *
+ *  per_cpu	RO bool	: whether the workqueue is per-cpu or unbound
+ *  max_active	RW int	: maximum number of in-flight work items
+ *
+ * Unbound workqueues have the following extra attributes.
+ *
+ *  pool_ids	RO int	: the associated pool IDs for each node
+ *  nice	RW int	: nice value of the workers
+ *  cpumask	RW mask	: bitmask of allowed CPUs for the workers
+ *  numa	RW bool	: whether enable NUMA affinity
+ */
+struct wq_device {
+	struct workqueue_struct		*wq;
+	struct device			dev;
+};
+
+static struct workqueue_struct *dev_to_wq(struct device *dev)
+{
+	struct wq_device *wq_dev = container_of(dev, struct wq_device, dev);
+
+	return wq_dev->wq;
+}
+
+static ssize_t per_cpu_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
+{
+	struct workqueue_struct *wq = dev_to_wq(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)!(wq->flags & WQ_UNBOUND));
+}
+static DEVICE_ATTR_RO(per_cpu);
+
+static ssize_t max_active_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct workqueue_struct *wq = dev_to_wq(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", wq->saved_max_active);
+}
+
+static ssize_t max_active_store(struct device *dev,
+				struct device_attribute *attr, const char *buf,
+				size_t count)
+{
+	struct workqueue_struct *wq = dev_to_wq(dev);
+	int val;
+
+	if (sscanf(buf, "%d", &val) != 1 || val <= 0)
+		return -EINVAL;
+
+	workqueue_set_max_active(wq, val);
+	return count;
+}
+static DEVICE_ATTR_RW(max_active);
+
+static struct attribute *wq_sysfs_attrs[] = {
+	&dev_attr_per_cpu.attr,
+	&dev_attr_max_active.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(wq_sysfs);
+
+static ssize_t wq_pool_ids_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct workqueue_struct *wq = dev_to_wq(dev);
+	const char *delim = "";
+	int node, written = 0;
+
+	cpus_read_lock();
+	rcu_read_lock();
+	for_each_node(node) {
+		written += scnprintf(buf + written, PAGE_SIZE - written,
+				     "%s%d:%d", delim, node,
+				     unbound_pwq_by_node(wq, node)->pool->id);
+		delim = " ";
+	}
+	written += scnprintf(buf + written, PAGE_SIZE - written, "\n");
+	rcu_read_unlock();
+	cpus_read_unlock();
+
+	return written;
+}
+
+static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
+{
+	struct workqueue_struct *wq = dev_to_wq(dev);
+	int written;
+
+	mutex_lock(&wq->mutex);
+	written = scnprintf(buf, PAGE_SIZE, "%d\n", wq->unbound_attrs->nice);
+	mutex_unlock(&wq->mutex);
+
+	return written;
+}
+
+/* prepare workqueue_attrs for sysfs store operations */
+static struct workqueue_attrs *wq_sysfs_prep_attrs(struct workqueue_struct *wq)
+{
+	struct workqueue_attrs *attrs;
+
+	lockdep_assert_held(&wq_pool_mutex);
+
+	attrs = alloc_workqueue_attrs();
+	if (!attrs)
+		return NULL;
+
+	copy_workqueue_attrs(attrs, wq->unbound_attrs);
+	return attrs;
+}
+
+static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct workqueue_struct *wq = dev_to_wq(dev);
+	struct workqueue_attrs *attrs;
+	int ret = -ENOMEM;
+
+	apply_wqattrs_lock();
+
+	attrs = wq_sysfs_prep_attrs(wq);
+	if (!attrs)
+		goto out_unlock;
+
+	if (sscanf(buf, "%d", &attrs->nice) == 1 &&
+	    attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE)
+		ret = apply_workqueue_attrs_locked(wq, attrs);
+	else
+		ret = -EINVAL;
+
+out_unlock:
+	apply_wqattrs_unlock();
+	free_workqueue_attrs(attrs);
+	return ret ?: count;
+}
+
+static ssize_t wq_cpumask_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct workqueue_struct *wq = dev_to_wq(dev);
+	int written;
+
+	mutex_lock(&wq->mutex);
+	written = scnprintf(buf, PAGE_SIZE, "%*pb\n",
+			    cpumask_pr_args(wq->unbound_attrs->cpumask));
+	mutex_unlock(&wq->mutex);
+	return written;
+}
+
+static ssize_t wq_cpumask_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct workqueue_struct *wq = dev_to_wq(dev);
+	struct workqueue_attrs *attrs;
+	int ret = -ENOMEM;
+
+	apply_wqattrs_lock();
+
+	attrs = wq_sysfs_prep_attrs(wq);
+	if (!attrs)
+		goto out_unlock;
+
+	ret = cpumask_parse(buf, attrs->cpumask);
+	if (!ret)
+		ret = apply_workqueue_attrs_locked(wq, attrs);
+
+out_unlock:
+	apply_wqattrs_unlock();
+	free_workqueue_attrs(attrs);
+	return ret ?: count;
+}
+
+static ssize_t wq_numa_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
+{
+	struct workqueue_struct *wq = dev_to_wq(dev);
+	int written;
+
+	mutex_lock(&wq->mutex);
+	written = scnprintf(buf, PAGE_SIZE, "%d\n",
+			    !wq->unbound_attrs->no_numa);
+	mutex_unlock(&wq->mutex);
+
+	return written;
+}
+
+static ssize_t wq_numa_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct workqueue_struct *wq = dev_to_wq(dev);
+	struct workqueue_attrs *attrs;
+	int v, ret = -ENOMEM;
+
+	apply_wqattrs_lock();
+
+	attrs = wq_sysfs_prep_attrs(wq);
+	if (!attrs)
+		goto out_unlock;
+
+	ret = -EINVAL;
+	if (sscanf(buf, "%d", &v) == 1) {
+		attrs->no_numa = !v;
+		ret = apply_workqueue_attrs_locked(wq, attrs);
+	}
+
+out_unlock:
+	apply_wqattrs_unlock();
+	free_workqueue_attrs(attrs);
+	return ret ?: count;
+}
+
+static struct device_attribute wq_sysfs_unbound_attrs[] = {
+	__ATTR(pool_ids, 0444, wq_pool_ids_show, NULL),
+	__ATTR(nice, 0644, wq_nice_show, wq_nice_store),
+	__ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store),
+	__ATTR(numa, 0644, wq_numa_show, wq_numa_store),
+	__ATTR_NULL,
+};
+
+static struct bus_type wq_subsys = {
+	.name				= "workqueue",
+	.dev_groups			= wq_sysfs_groups,
+};
+
+static ssize_t wq_unbound_cpumask_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	int written;
+
+	mutex_lock(&wq_pool_mutex);
+	written = scnprintf(buf, PAGE_SIZE, "%*pb\n",
+			    cpumask_pr_args(wq_unbound_cpumask));
+	mutex_unlock(&wq_pool_mutex);
+
+	return written;
+}
+
+static ssize_t wq_unbound_cpumask_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	cpumask_var_t cpumask;
+	int ret;
+
+	if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))
+		return -ENOMEM;
+
+	ret = cpumask_parse(buf, cpumask);
+	if (!ret)
+		ret = workqueue_set_unbound_cpumask(cpumask);
+
+	free_cpumask_var(cpumask);
+	return ret ? ret : count;
+}
+
+static struct device_attribute wq_sysfs_cpumask_attr =
+	__ATTR(cpumask, 0644, wq_unbound_cpumask_show,
+	       wq_unbound_cpumask_store);
+
+static int __init wq_sysfs_init(void)
+{
+	int err;
+
+	err = subsys_virtual_register(&wq_subsys, NULL);
+	if (err)
+		return err;
+
+	return device_create_file(wq_subsys.dev_root, &wq_sysfs_cpumask_attr);
+}
+core_initcall(wq_sysfs_init);
+
+static void wq_device_release(struct device *dev)
+{
+	struct wq_device *wq_dev = container_of(dev, struct wq_device, dev);
+
+	kfree(wq_dev);
+}
+
+/**
+ * workqueue_sysfs_register - make a workqueue visible in sysfs
+ * @wq: the workqueue to register
+ *
+ * Expose @wq in sysfs under /sys/bus/workqueue/devices.
+ * alloc_workqueue*() automatically calls this function if WQ_SYSFS is set
+ * which is the preferred method.
+ *
+ * Workqueue user should use this function directly iff it wants to apply
+ * workqueue_attrs before making the workqueue visible in sysfs; otherwise,
+ * apply_workqueue_attrs() may race against userland updating the
+ * attributes.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int workqueue_sysfs_register(struct workqueue_struct *wq)
+{
+	struct wq_device *wq_dev;
+	int ret;
+
+	/*
+	 * Adjusting max_active or creating new pwqs by applying
+	 * attributes breaks ordering guarantee.  Disallow exposing ordered
+	 * workqueues.
+	 */
+	if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
+		return -EINVAL;
+
+	wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL);
+	if (!wq_dev)
+		return -ENOMEM;
+
+	wq_dev->wq = wq;
+	wq_dev->dev.bus = &wq_subsys;
+	wq_dev->dev.release = wq_device_release;
+	dev_set_name(&wq_dev->dev, "%s", wq->name);
+
+	/*
+	 * unbound_attrs are created separately.  Suppress uevent until
+	 * everything is ready.
+	 */
+	dev_set_uevent_suppress(&wq_dev->dev, true);
+
+	ret = device_register(&wq_dev->dev);
+	if (ret) {
+		put_device(&wq_dev->dev);
+		wq->wq_dev = NULL;
+		return ret;
+	}
+
+	if (wq->flags & WQ_UNBOUND) {
+		struct device_attribute *attr;
+
+		for (attr = wq_sysfs_unbound_attrs; attr->attr.name; attr++) {
+			ret = device_create_file(&wq_dev->dev, attr);
+			if (ret) {
+				device_unregister(&wq_dev->dev);
+				wq->wq_dev = NULL;
+				return ret;
+			}
+		}
+	}
+
+	dev_set_uevent_suppress(&wq_dev->dev, false);
+	kobject_uevent(&wq_dev->dev.kobj, KOBJ_ADD);
+	return 0;
+}
+
+/**
+ * workqueue_sysfs_unregister - undo workqueue_sysfs_register()
+ * @wq: the workqueue to unregister
+ *
+ * If @wq is registered to sysfs by workqueue_sysfs_register(), unregister.
+ */
+static void workqueue_sysfs_unregister(struct workqueue_struct *wq)
+{
+	struct wq_device *wq_dev = wq->wq_dev;
+
+	if (!wq->wq_dev)
+		return;
+
+	wq->wq_dev = NULL;
+	device_unregister(&wq_dev->dev);
+}
+#else	/* CONFIG_SYSFS */
+static void workqueue_sysfs_unregister(struct workqueue_struct *wq)	{ }
+#endif	/* CONFIG_SYSFS */
+
+/*
+ * Workqueue watchdog.
+ *
+ * Stall may be caused by various bugs - missing WQ_MEM_RECLAIM, illegal
+ * flush dependency, a concurrency managed work item which stays RUNNING
+ * indefinitely.  Workqueue stalls can be very difficult to debug as the
+ * usual warning mechanisms don't trigger and internal workqueue state is
+ * largely opaque.
+ *
+ * Workqueue watchdog monitors all worker pools periodically and dumps
+ * state if some pools failed to make forward progress for a while where
+ * forward progress is defined as the first item on ->worklist changing.
+ *
+ * This mechanism is controlled through the kernel parameter
+ * "workqueue.watchdog_thresh" which can be updated at runtime through the
+ * corresponding sysfs parameter file.
+ */
+#ifdef CONFIG_WQ_WATCHDOG
+
+static unsigned long wq_watchdog_thresh = 30;
+static struct timer_list wq_watchdog_timer;
+
+static unsigned long wq_watchdog_touched = INITIAL_JIFFIES;
+static DEFINE_PER_CPU(unsigned long, wq_watchdog_touched_cpu) = INITIAL_JIFFIES;
+
+static void wq_watchdog_reset_touched(void)
+{
+	int cpu;
+
+	wq_watchdog_touched = jiffies;
+	for_each_possible_cpu(cpu)
+		per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies;
+}
+
+static void wq_watchdog_timer_fn(struct timer_list *unused)
+{
+	unsigned long thresh = READ_ONCE(wq_watchdog_thresh) * HZ;
+	bool lockup_detected = false;
+	unsigned long now = jiffies;
+	struct worker_pool *pool;
+	int pi;
+
+	if (!thresh)
+		return;
+
+	rcu_read_lock();
+
+	for_each_pool(pool, pi) {
+		unsigned long pool_ts, touched, ts;
+
+		if (list_empty(&pool->worklist))
+			continue;
+
+		/*
+		 * If a virtual machine is stopped by the host it can look to
+		 * the watchdog like a stall.
+		 */
+		kvm_check_and_clear_guest_paused();
+
+		/* get the latest of pool and touched timestamps */
+		if (pool->cpu >= 0)
+			touched = READ_ONCE(per_cpu(wq_watchdog_touched_cpu, pool->cpu));
+		else
+			touched = READ_ONCE(wq_watchdog_touched);
+		pool_ts = READ_ONCE(pool->watchdog_ts);
+
+		if (time_after(pool_ts, touched))
+			ts = pool_ts;
+		else
+			ts = touched;
+
+		/* did we stall? */
+		if (time_after(now, ts + thresh)) {
+			lockup_detected = true;
+			pr_emerg("BUG: workqueue lockup - pool");
+			pr_cont_pool_info(pool);
+			pr_cont(" stuck for %us!\n",
+				jiffies_to_msecs(now - pool_ts) / 1000);
+		}
+	}
+
+	rcu_read_unlock();
+
+	if (lockup_detected)
+		show_all_workqueues();
+
+	wq_watchdog_reset_touched();
+	mod_timer(&wq_watchdog_timer, jiffies + thresh);
+}
+
+notrace void wq_watchdog_touch(int cpu)
+{
+	if (cpu >= 0)
+		per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies;
+
+	wq_watchdog_touched = jiffies;
+}
+
+static void wq_watchdog_set_thresh(unsigned long thresh)
+{
+	wq_watchdog_thresh = 0;
+	del_timer_sync(&wq_watchdog_timer);
+
+	if (thresh) {
+		wq_watchdog_thresh = thresh;
+		wq_watchdog_reset_touched();
+		mod_timer(&wq_watchdog_timer, jiffies + thresh * HZ);
+	}
+}
+
+static int wq_watchdog_param_set_thresh(const char *val,
+					const struct kernel_param *kp)
+{
+	unsigned long thresh;
+	int ret;
+
+	ret = kstrtoul(val, 0, &thresh);
+	if (ret)
+		return ret;
+
+	if (system_wq)
+		wq_watchdog_set_thresh(thresh);
+	else
+		wq_watchdog_thresh = thresh;
+
+	return 0;
+}
+
+static const struct kernel_param_ops wq_watchdog_thresh_ops = {
+	.set	= wq_watchdog_param_set_thresh,
+	.get	= param_get_ulong,
+};
+
+module_param_cb(watchdog_thresh, &wq_watchdog_thresh_ops, &wq_watchdog_thresh,
+		0644);
+
+static void wq_watchdog_init(void)
+{
+	timer_setup(&wq_watchdog_timer, wq_watchdog_timer_fn, TIMER_DEFERRABLE);
+	wq_watchdog_set_thresh(wq_watchdog_thresh);
+}
+
+#else	/* CONFIG_WQ_WATCHDOG */
+
+static inline void wq_watchdog_init(void) { }
+
+#endif	/* CONFIG_WQ_WATCHDOG */
+
+static void __init wq_numa_init(void)
+{
+	cpumask_var_t *tbl;
+	int node, cpu;
+
+	if (num_possible_nodes() <= 1)
+		return;
+
+	if (wq_disable_numa) {
+		pr_info("workqueue: NUMA affinity support disabled\n");
+		return;
+	}
+
+	for_each_possible_cpu(cpu) {
+		if (WARN_ON(cpu_to_node(cpu) == NUMA_NO_NODE)) {
+			pr_warn("workqueue: NUMA node mapping not available for cpu%d, disabling NUMA support\n", cpu);
+			return;
+		}
+	}
+
+	wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs();
+	BUG_ON(!wq_update_unbound_numa_attrs_buf);
+
+	/*
+	 * We want masks of possible CPUs of each node which isn't readily
+	 * available.  Build one from cpu_to_node() which should have been
+	 * fully initialized by now.
+	 */
+	tbl = kcalloc(nr_node_ids, sizeof(tbl[0]), GFP_KERNEL);
+	BUG_ON(!tbl);
+
+	for_each_node(node)
+		BUG_ON(!zalloc_cpumask_var_node(&tbl[node], GFP_KERNEL,
+				node_online(node) ? node : NUMA_NO_NODE));
+
+	for_each_possible_cpu(cpu) {
+		node = cpu_to_node(cpu);
+		cpumask_set_cpu(cpu, tbl[node]);
+	}
+
+	wq_numa_possible_cpumask = tbl;
+	wq_numa_enabled = true;
+}
+
+/**
+ * workqueue_init_early - early init for workqueue subsystem
+ *
+ * This is the first half of two-staged workqueue subsystem initialization
+ * and invoked as soon as the bare basics - memory allocation, cpumasks and
+ * idr are up.  It sets up all the data structures and system workqueues
+ * and allows early boot code to create workqueues and queue/cancel work
+ * items.  Actual work item execution starts only after kthreads can be
+ * created and scheduled right before early initcalls.
+ */
+void __init workqueue_init_early(void)
+{
+	int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL };
+	int i, cpu;
+
+	BUILD_BUG_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));
+
+	BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL));
+	cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_WQ));
+	cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_DOMAIN));
+
+	pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);
+
+	/* initialize CPU pools */
+	for_each_possible_cpu(cpu) {
+		struct worker_pool *pool;
+
+		i = 0;
+		for_each_cpu_worker_pool(pool, cpu) {
+			BUG_ON(init_worker_pool(pool));
+			pool->cpu = cpu;
+			cpumask_copy(pool->attrs->cpumask, cpumask_of(cpu));
+			pool->attrs->nice = std_nice[i++];
+			pool->node = cpu_to_node(cpu);
+
+			/* alloc pool ID */
+			mutex_lock(&wq_pool_mutex);
+			BUG_ON(worker_pool_assign_id(pool));
+			mutex_unlock(&wq_pool_mutex);
+		}
+	}
+
+	/* create default unbound and ordered wq attrs */
+	for (i = 0; i < NR_STD_WORKER_POOLS; i++) {
+		struct workqueue_attrs *attrs;
+
+		BUG_ON(!(attrs = alloc_workqueue_attrs()));
+		attrs->nice = std_nice[i];
+		unbound_std_wq_attrs[i] = attrs;
+
+		/*
+		 * An ordered wq should have only one pwq as ordering is
+		 * guaranteed by max_active which is enforced by pwqs.
+		 * Turn off NUMA so that dfl_pwq is used for all nodes.
+		 */
+		BUG_ON(!(attrs = alloc_workqueue_attrs()));
+		attrs->nice = std_nice[i];
+		attrs->no_numa = true;
+		ordered_wq_attrs[i] = attrs;
+	}
+
+	system_wq = alloc_workqueue("events", 0, 0);
+	system_highpri_wq = alloc_workqueue("events_highpri", WQ_HIGHPRI, 0);
+	system_long_wq = alloc_workqueue("events_long", 0, 0);
+	system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND,
+					    WQ_UNBOUND_MAX_ACTIVE);
+	system_freezable_wq = alloc_workqueue("events_freezable",
+					      WQ_FREEZABLE, 0);
+	system_power_efficient_wq = alloc_workqueue("events_power_efficient",
+					      WQ_POWER_EFFICIENT, 0);
+	system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_power_efficient",
+					      WQ_FREEZABLE | WQ_POWER_EFFICIENT,
+					      0);
+	BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq ||
+	       !system_unbound_wq || !system_freezable_wq ||
+	       !system_power_efficient_wq ||
+	       !system_freezable_power_efficient_wq);
+}
+
+/**
+ * workqueue_init - bring workqueue subsystem fully online
+ *
+ * This is the latter half of two-staged workqueue subsystem initialization
+ * and invoked as soon as kthreads can be created and scheduled.
+ * Workqueues have been created and work items queued on them, but there
+ * are no kworkers executing the work items yet.  Populate the worker pools
+ * with the initial workers and enable future kworker creations.
+ */
+void __init workqueue_init(void)
+{
+	struct workqueue_struct *wq;
+	struct worker_pool *pool;
+	int cpu, bkt;
+
+	/*
+	 * It'd be simpler to initialize NUMA in workqueue_init_early() but
+	 * CPU to node mapping may not be available that early on some
+	 * archs such as power and arm64.  As per-cpu pools created
+	 * previously could be missing node hint and unbound pools NUMA
+	 * affinity, fix them up.
+	 *
+	 * Also, while iterating workqueues, create rescuers if requested.
+	 */
+	wq_numa_init();
+
+	mutex_lock(&wq_pool_mutex);
+
+	for_each_possible_cpu(cpu) {
+		for_each_cpu_worker_pool(pool, cpu) {
+			pool->node = cpu_to_node(cpu);
+		}
+	}
+
+	list_for_each_entry(wq, &workqueues, list) {
+		wq_update_unbound_numa(wq, smp_processor_id(), true);
+		WARN(init_rescuer(wq),
+		     "workqueue: failed to create early rescuer for %s",
+		     wq->name);
+	}
+
+	mutex_unlock(&wq_pool_mutex);
+
+	/* create the initial workers */
+	for_each_online_cpu(cpu) {
+		for_each_cpu_worker_pool(pool, cpu) {
+			pool->flags &= ~POOL_DISASSOCIATED;
+			BUG_ON(!create_worker(pool));
+		}
+	}
+
+	hash_for_each(unbound_pool_hash, bkt, pool, hash_node)
+		BUG_ON(!create_worker(pool));
+
+	wq_online = true;
+	wq_watchdog_init();
+}
+
+/*
+ * Despite the naming, this is a no-op function which is here only for avoiding
+ * link error. Since compile-time warning may fail to catch, we will need to
+ * emit run-time warning from __flush_workqueue().
+ */
+void __warn_flushing_systemwide_wq(void) { }
+EXPORT_SYMBOL(__warn_flushing_systemwide_wq);
diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h
new file mode 100644
index 000000000..e00b1204a
--- /dev/null
+++ b/kernel/workqueue_internal.h
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * kernel/workqueue_internal.h
+ *
+ * Workqueue internal header file.  Only to be included by workqueue and
+ * core kernel subsystems.
+ */
+#ifndef _KERNEL_WORKQUEUE_INTERNAL_H
+#define _KERNEL_WORKQUEUE_INTERNAL_H
+
+#include <linux/workqueue.h>
+#include <linux/kthread.h>
+#include <linux/preempt.h>
+
+struct worker_pool;
+
+/*
+ * The poor guys doing the actual heavy lifting.  All on-duty workers are
+ * either serving the manager role, on idle list or on busy hash.  For
+ * details on the locking annotation (L, I, X...), refer to workqueue.c.
+ *
+ * Only to be used in workqueue and async.
+ */
+struct worker {
+	/* on idle list while idle, on busy hash table while busy */
+	union {
+		struct list_head	entry;	/* L: while idle */
+		struct hlist_node	hentry;	/* L: while busy */
+	};
+
+	struct work_struct	*current_work;	/* L: work being processed */
+	work_func_t		current_func;	/* L: current_work's fn */
+	struct pool_workqueue	*current_pwq;	/* L: current_work's pwq */
+	unsigned int		current_color;	/* L: current_work's color */
+	struct list_head	scheduled;	/* L: scheduled works */
+
+	/* 64 bytes boundary on 64bit, 32 on 32bit */
+
+	struct task_struct	*task;		/* I: worker task */
+	struct worker_pool	*pool;		/* A: the associated pool */
+						/* L: for rescuers */
+	struct list_head	node;		/* A: anchored at pool->workers */
+						/* A: runs through worker->node */
+
+	unsigned long		last_active;	/* L: last active timestamp */
+	unsigned int		flags;		/* X: flags */
+	int			id;		/* I: worker id */
+	int			sleeping;	/* None */
+
+	/*
+	 * Opaque string set with work_set_desc().  Printed out with task
+	 * dump for debugging - WARN, BUG, panic or sysrq.
+	 */
+	char			desc[WORKER_DESC_LEN];
+
+	/* used only by rescuers to point to the target workqueue */
+	struct workqueue_struct	*rescue_wq;	/* I: the workqueue to rescue */
+
+	/* used by the scheduler to determine a worker's last known identity */
+	work_func_t		last_func;
+};
+
+/**
+ * current_wq_worker - return struct worker if %current is a workqueue worker
+ */
+static inline struct worker *current_wq_worker(void)
+{
+	if (in_task() && (current->flags & PF_WQ_WORKER))
+		return kthread_data(current);
+	return NULL;
+}
+
+/*
+ * Scheduler hooks for concurrency managed workqueue.  Only to be used from
+ * sched/ and workqueue.c.
+ */
+void wq_worker_running(struct task_struct *task);
+void wq_worker_sleeping(struct task_struct *task);
+work_func_t wq_worker_last_func(struct task_struct *task);
+
+#endif /* _KERNEL_WORKQUEUE_INTERNAL_H */